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Umwelttoxikologie - Aktuelle Forschungsartikel renommierter Fachzeitschriften


 
Aktuelle Fachartikel zur Umwelttoxikologie, sortiert nach Erscheinungsdatum.

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Auf dieser Seite beruecksichtige naturwissenschaftliche Journale:


Ecotoxicology Ecotoxicology - published by Springer -
... is an international journal devoted to the publication of fundamental research on the effects of toxic chemicals on populations, communities and terrestrial, freshwater and marine ecosystems.

Environmental Toxicology - published by Wiley-Interscience -
The journal publishes in the areas of toxicity and toxicology of environmental pollutants in air, dust, sediment, soil and water, and natural toxins in the environment.



Aktuelle wissenschaftliche Fachartikel der genannten Journale:


Effects of heavy metals on the expression of a zinc-inducible metallothionein-III gene and antioxidant enzyme activities in Crassostrea gigas

Abstract  
Sequestration by metallothioneins and antioxidant defense are two kinds of important defense mechanisms employed by mollusks to minimize adverse effects caused by heavy metal contaminants in marine environment. In the present study, a novel metallothionein gene, CgMT-III, was cloned from Crassostrea gigas, consisting of eighteen conserved cysteine residues and encoding a MT III-like protein with two tandem β domains. The expression level of CgMT-III transcript induced by zinc was much higher than that induced by cadmium exposure. It suggested that CgMT-III was perhaps mainly involved in homeostatic control of zinc metabolism, which was distinct from previously identified MTs in C. gigas. Among the tested antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), SOD and GPx showed varying up-regulations in a tissue-specific manner, while CAT activities were inhibited in both gill and hepatopancreas from C. gigas exposed to heavy metals. It can be inferred that CgMT-III was mainly involved in zinc homeostasis, and CgMT-III gene together with CAT enzyme could be potential biomarkers to indicate heavy metal, especially zinc pollution in marine organisms.

  • Content Type Journal Article
  • Pages 1-9
  • DOI 10.1007/s10646-012-0926-z
  • Authors
    • Ming Cong, Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai, 264003 Shandong, People’s Republic of China
    • Huifeng Wu, Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai, 264003 Shandong, People’s Republic of China
    • Xiaoli Liu, Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai, 264003 Shandong, People’s Republic of China
    • Jianmin Zhao, Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai, 264003 Shandong, People’s Republic of China
    • Xuan Wang, Ocean University of China, Qingdao, 266100 Shandong, People’s Republic of China
    • Jiasen Lv, Ocean School of Yantai University, Yantai, 264005 Shandong, People’s Republic of China
    • Lin Hou, Ocean School of Yantai University, Yantai, 264005 Shandong, People’s Republic of China

Quelle: Ecotoxicology (Browse Results) | 22 May 2012 | 10:27 am CEST

Effects of imidacloprid, a neonicotinoid pesticide, on reproduction in worker bumble bees (Bombus terrestris)

Abstract  
Bumble bees are important pollinators whose populations have declined over recent years, raising widespread concern. One conspicuous threat to bumble bees is their unintended exposure to trace residues of systemic neonicotinoid pesticides, such as imidacloprid, which are ingested when bees forage on the nectar and pollen of treated crops. However, the demographic consequences for bumble bees of exposure to dietary neonicotinoids have yet to be fully established. To determine whether environmentally realistic levels of imidacloprid are capable of making a demographic impact on bumble bees, we exposed queenless microcolonies of worker bumble bees, Bombus terrestris, to a range of dosages of dietary imidacloprid between zero and 125 Î¼g L−1 and examined the effects on ovary development and fecundity. Microcolonies showed a dose-dependent decline in fecundity, with environmentally realistic dosages in the range of 1 Î¼g L−1 capable of reducing brood production by one third. In contrast, ovary development was unimpaired by dietary imidacloprid except at the highest dosage. Imidacloprid reduced feeding on both syrup and pollen but, after controlling statistically for dosage, microcolonies that consumed more syrup and pollen produced more brood. We therefore speculate that the detrimental effects of imidacloprid on fecundity emerge principally from nutrient limitation imposed by the failure of individuals to feed. Our findings raise concern about the impact of neonicotinoids on wild bumble bee populations. However, we recognize that to fully evaluate impacts on wild colonies it will be necessary to establish the effect of dietary neonicotinoids on the fecundity of bumble bee queens.

  • Content Type Journal Article
  • Pages 1-9
  • DOI 10.1007/s10646-012-0927-y
  • Authors
    • Ian Laycock, Department of Biosciences, College of Life & Environmental Sciences, University of Exeter, Hatherly Laboratories, Prince of Wales Road, Exeter, EX4 4PS UK
    • Kate M. Lenthall, Department of Biosciences, College of Life & Environmental Sciences, University of Exeter, Hatherly Laboratories, Prince of Wales Road, Exeter, EX4 4PS UK
    • Andrew T. Barratt, Department of Mathematics and Computer Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Harrison Building, North Park Road, Exeter, EX4 4QF UK
    • James E. Cresswell, Department of Biosciences, College of Life & Environmental Sciences, University of Exeter, Hatherly Laboratories, Prince of Wales Road, Exeter, EX4 4PS UK

Quelle: Ecotoxicology (Browse Results) | 22 May 2012 | 10:27 am CEST

The potential for adaptation in a natural Daphnia magna population: broad and narrow-sense heritability of net reproductive rate under Cd stress at two temperatures

Abstract  
The existence of genetic variability is a key element of the adaptive potential of a natural population to stress. In this study we estimated the additive and non-additive components of the genetic variability of net reproductive rate (R0) in a natural Daphnia magna population exposed to Cd stress at two different temperatures. To this end, life-table experiments were conducted with 20 parental and 39 offspring clonal lineages following a 2 Ã— 2 design with Cd concentration (control vs. 3.7 Î¼g Cd/L) and temperature (20 vs. 24 Â°C) as factors. Offspring lineages were obtained through inter-clonal crossing of the different parental lineages. The population mean, additive and non-additive genetic components of variation in each treatment were estimated by fitting an Animal Model to the observed R0 values using restricted maximum likelihood estimation. From those estimates broad-sense heritabilities (H2), narrow-sense heritabilities (h2), total (CVG) and additive genetic coefficients of variation (CVA) of R0 were calculated. The exposure to Cd imposed a considerable level of stress to the population, as shown by the fact that the population mean of R0 exposed to Cd was significantly lower than in the control at the corresponding temperature, i.e. by 23 % at 20 Â°C and by 88 % at 24 Â°C. The latter difference indicates that increasing temperature increased the stress level imposed by Cd. The H² and CVG were significantly greater than 0 in all treatments, suggesting that there is a considerable degree of genetic determination of R0 in this population and that clonal selection could rapidly lead to increasing population mean fitness under all investigated conditions. More specifically, the H² was 0.392 at 20 Â°C+Cd and 0.563 at 24 Â°C+Cd; the CVG was 30.0 % at 20 Â°C+Cd and was significantly higher (147.6 %) in the 24 Â°C+Cd treatment. Significant values of h2 (= 0.23) and CVA (= 89.7 %) were only found in the 24 Â°C+Cd treatment, suggesting that the ability to produce more offspring under this stressful condition may be inherited across sexual generations. In contrast, in the less stressful 20 Â°C+Cd treatment the h2 (0.06) and CVA (7.0 %) were very low and not significantly higher than zero. Collectively our data indicate that both the asexual and sexual reproduction phases in cyclic parthenogenetic D. magna populations may play a role in the long-term adaptive potential of Daphnia populations to chemical stress (with Cd as the current example) and that environmental variables which influence the stress level of that chemical may influence this adaptive potential (with temperature as current example).

  • Content Type Journal Article
  • Pages 1-12
  • DOI 10.1007/s10646-012-0923-2
  • Authors
    • M. Messiaen, Laboratory of Environmental Toxicology and Aquatic Ecology, Department Applied Ecology and Environmental Biology, Ghent University, Jozef Plateaustraat 22, 9000 Ghent, Belgium
    • C. R. Janssen, Laboratory of Environmental Toxicology and Aquatic Ecology, Department Applied Ecology and Environmental Biology, Ghent University, Jozef Plateaustraat 22, 9000 Ghent, Belgium
    • O. Thas, Department of Mathematical Modelling Statistics and Bio-informatics, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
    • K. A. C. De Schamphelaere, Laboratory of Environmental Toxicology and Aquatic Ecology, Department Applied Ecology and Environmental Biology, Ghent University, Jozef Plateaustraat 22, 9000 Ghent, Belgium

Quelle: Ecotoxicology (Browse Results) | 22 May 2012 | 10:27 am CEST

Benzo[a]pyrene modulation of acute immunologic responses in red Sea bream pretreated with lipopolysaccharide

Abstract

The effects of polycyclic aromatic hydrocarbons (PAHs) have been reported to modulate the immune response in aquatic animals, but the collected information of their effects on fish immunity is so far ambiguous. This study demonstrated that Benzo[a]pyrene (BaP) exposure altered the expression pattern of an antimicrobial peptide hepcidin (PM-hepc) gene and the activities of some immune-associated parameters in the lipopolysaccharide (LPS)-challenged red sea bream (Pagrus major). It was observed that LPS could increase respiratory burst, lysozyme and antibacterial activity in P. major. However when the P. major was exposed to different concentrations of BaP (1, 4, or 8 μg L−1) for 14 days and then challenged with LPS there was no significant change in the lysozyme and antibacterial activity. It was further observed that LPS could induce the PM-hepc mRNA expression at 3, 6, and 12-h post-LPS challenge. However, when P. major was exposed first to BaP for 14 days and then challenged with LPS, the expression of PM-hepc mRNA was delayed in the liver until 24 h and not significantly induced until 48 and 96 h. The mRNA expression pattern was completely different from that only with LPS challenge, showing that BaP exposure changed the PM-hepc mRNA expression pattern of fish with LPS challenge. This study demonstrated that BaP exposure can weaken or inhibit the induction of lysozyme and antibacterial activity in the LPS-challenged P. major; conversely BaP exposure could enhance the mRNA expression of PM-hepc gene, indicating that the effect of BaP has different modulatory mechanism on hepcidin genes and immune-associated parameters. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 19 May 2012 | 1:12 pm CEST

Responses of biomarkers of a standardized (Cyprinus carpio) and a native (Pimelodella laticeps) fish species after in situ exposure in a periurban zone of Luján river (Argentina)

Abstract

The Luján River basin, which is located in the northwest area of the province of Buenos Aires, Argentina, receives different anthropogenic inputs before reaching the Río de la Plata estuary. The aim of this study was to assess the adverse impact of the river in the middle part of the basin. To this end, an in situ cage assay was conducted in two sites of the river (S1 and S2) near Luján city, and the responses of hepatic biomarkers of both a standardized (Cyprinus carpio) and a native (Pimelodella laticeps) species were evaluated. The biomarkers studied were the condition factor and liver somatic indices (LSI), the enzymatic activities of catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST), lipid peroxidation levels (thiobarbituric acid reactive substances, TBARS) and the induction of hepatic cytochrome P450 1A (CYP1A) and vitellogenin (Vtg) proteins. After 14 days, LSI and GST activity increased, and TBARS levels decreased in both species exposed at S1 and S2. In addition, exposure at both sites promoted an increase in SOD activity and CYP1A induction in C. carpio, while Vtg expression was observed only at S1. A shorter exposure period (7 days) caused an initial response only at S2 mediated only by CAT in P. laticeps. Finally, our results demonstrate that a 14-day period of in situ exposure in Luján River could lead to antioxidant and biotransformation processes in C. carpio and to phase II biotransformation responses in P. laticeps. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 19 May 2012 | 1:12 pm CEST

Human dna damage by the synergistic action of 4-aminobiphenyl and nitric oxide: An immunochemical study

Abstract

4-Aminobiphenyl (4-ABP), an aromatic amine is a major environmental carcinogen found mainly in cigarette smoke. It has been vastly implicated in mutagenesis and cancer development. In this study, commercially available human placental DNA was exposed to 4-ABP (1.3 mM) in presence of sodium nitroprusside (SNP; 8 mM) at 37°C for 3 h. The 4-ABP + SNP-mediated structural changes in human DNA were studied by ultraviolet, circular dichroism and fluorescence spectroscopy, thermal melting profile, agarose gel electrophoresis, and nuclease S1 digestibility assay. Spectroscopical analysis and melting temperature studies suggest structural perturbations in the DNA as a result of modification. This might be due to generation of single-stranded regions and destabilization of hydrogen bonds. Modification was also visualized in agarose gel electrophoresis. Furthermore, nuclease S1 digestibility confirmed the generation of single strand breaks. Rabbits challenged with 4-ABP-SNP-modified human DNA-induced high-titer immunogen-specific antibodies, which showed Cross-reaction with modified/unmodified DNA bases and ss-DNA in competitive inhibition assay. The immunogen specificity of induced antibodies against 4-ABP-SNP-modified human DNA was further confirmed in gel retardation assay. It may be concluded that induction of anti-modified DNA antibodies could be due to perturbation in the DNA structure and its subsequent recognition by immunoregulatory cells as a foreign molecule. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 19 May 2012 | 1:12 pm CEST

Assessment of the genotoxic effects of organophosphorus insecticides phorate and trichlorfon in human lymphocytes

Abstract

In vitro genotoxic effects of organophosphorus insecticides Phorate (PHR) and Trichlorfon (TCF) were investigated using four genotoxicity endpoints. Different concentration ranges between 0.25–2.00 μg mL−1 of PHR and 2.34–37.50 μg mL−1 of TCF were applied to lymphocytes. PHR and TCF significantly increased the frequency of chromosomal aberrations (except 2.34 μg mL−1 for TCF) and sister chromatid exchanges at all treatment times and concentrations. Most of the used concentrations induced a significant increase in the frequency of micronuclei. Furthermore, PHR and TCF significantly decreased the mitotic index at the higher concentrations after 24- and 48-h treatments. In the comet assay, PHR and TCF significantly increased the comet tail at all concentrations. However, the comet tail intensity was significantly increased at only the highest concentration of PHR and at all concentrations of TCF. According to these results, PHR and TCF possess clastogenic, mutagenic, and DNA damaging effects in human lymphocytes in vitro. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 19 May 2012 | 1:12 pm CEST

Fluoride decreased osteoclastic bone resorption through the inhibition of NFATc1 gene expression

Abstract

Over the past two decades, fluoride effects on osteoclasts have been evaluated; however, its molecular mechanisms remain unclear. In this study, we investigated the effect of fluoride on osteoclast formation, function, and regulation using osteoclasts formed from mice bone marrow macrophages treated with the receptor activator of NF-κB ligand and macrophage colony-stimulating factor. Our data showed that fluoride levels ≤ 8 mg/L had no effect on osteoclast formation; however, it significantly reduced osteoclast resorption at 0.5 mg/L. Fluoride activity on bone resorption occurred through the inhibition of nuclear factor of active T cells (NFAT) c1 expression. Furthermore, the expression of its downstream genes, including the dendritic cell-specific transmembrane protein, c-Src, the d2 isoform of vacuolar (H+) ATPase v0 domain, matrix metalloproteinase 9, and cathepsin K were decreased, leading to impaired osteoclast acidification, reduced secretion of proteolytic enzymes, and decreased bone resorption. In summary, our results suggested that fluoride has different roles in osteoclast formation and function. Fluoride ≤ 8 mg/L did not impact osteoclast formation; however, it significantly decreased the resorption activity of newly formed osteoclasts. The molecular mechanism of fluoride action may involve inhibition of NFATc1 and its downstream genes. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 19 May 2012 | 1:12 pm CEST

Perinatal exposure to di-(2-ethylhexyl)-phthalate leads to cognitive dysfunction and phospho-tau level increase in aged rats

Abstract

Di-(2-ethylhexyl)-Phthalate (DEHP) can affect glucose and insulin homeostasis in periphery and lead to insulin resistance, especially exposure of DEHP during critical developmental period. Given the potential relationship between insulin resistance and pathogenesis of Alzheimer's disease (AD) in elderly life, we investigated the relationship between perinatal DEHP exposure and AD pathogenesis. Our results suggested that perinatal exposure to DEHP can affect the expression of insulin and insulin-Akt- GSK-3β signal pathway in hippocampus. Furthermore, impaired cognitive ability and increased level of phospho-Tau was observed in DEHP-exposed rat offspring (1.25 ± 0.11 vs. 0.47 ± 0.07, P < 0.05). The present study demonstrates that perinatal exposure to DEHP may be a potential risk factor for AD pathogenesis associated with insulin resistance and insulin metabolism disorder in the hippocampus. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 19 May 2012 | 1:11 pm CEST

An evaluation of the combined effects of phenolic endocrine disruptors on vitellogenin induction in goldfish Carassius auratus

Abstract  
Phenolic compounds are widely distributed in the natural environment, typically existing as a mixture at the nanogram or microgram per liter level. Among the phenolic compounds, 4-nonylphenol, 4-t-octylphenol, bisphenol A and 2,4-dichlorophenol attract the most concern due to their abundance and risks within the natural environment. The former three chemicals are known as endocrine disruptors causing feminization in various organisms, whereas the latter one requires further clarification concerning its feminization effect. This study aims to evaluate the combined effects of these chemicals using vitellogenin protein induction in male juvenile goldfish Carassius auratus as an endpoint after 15 days of exposure. The results showed that all these chemicals can induce vitellogenin with a relative potency of 4-t-octylphenol > bisphenol A > 4-nonylphenol â‰« 2,4-dichlorophenol. 2,4-dichlorophenol showed a very weak estrogenic effect with an induction of vitellogenin concentration of <1 % of positive control, and it is therefore omitted in further tests to evaluate their combined effect. The other three chemicals were mixed in two ways, at an equipotent ratio and at an equal environmental level ratio, and their combined effects were evaluated with both the toxicity units method and concentration addition model. The resulting effect of exposure to both mixtures showed that these chemicals generally exhibited an additive effect. The ecological risk of phenolic chemicals may therefore be underestimated if based on the presence of single chemicals whereas their combined effects warrant further consideration.

  • Content Type Journal Article
  • Pages 1-9
  • DOI 10.1007/s10646-012-0925-0
  • Authors
    • Zhengyan Li, College of Environmental Science and Engineering, Ocean University of China, 238 Songling Road, 266100 Qingdao, People’s Republic of China
    • Haili Zhang, College of Environmental Science and Engineering, Ocean University of China, 238 Songling Road, 266100 Qingdao, People’s Republic of China
    • Mark Gibson, Department of Process Engineering and Applied Science, Dalhousie University, Sexton Campus, 1360 Barrington St., P.O. Box 15000, Halifax, NS B3J 2X4, Canada
    • Ping Liu, College of Environmental Science and Engineering, Ocean University of China, 238 Songling Road, 266100 Qingdao, People’s Republic of China

Quelle: Ecotoxicology (Browse Results) | 17 May 2012 | 5:16 pm CEST

Effects of alkali stress on growth, free amino acids and carbohydrates metabolism in Kentucky bluegrass (Poa pratensis)

Abstract  
Soil alkalization is one of the most prominent adverse environmental factors limiting plant growth, while alkali stress affects amino acids and carbohydrates metabolism. The objective of this study was conducted to investigate the effects of alkali stress on growth, amino acids and carbohydrates metabolism in Kentucky bluegrass (Poa pratensis). Seventy-day-old plants were subjected to four pH levels: 6.0 (control), 8.0 (low), 9.4 (moderate) and 10.3 (severe) for 7 days. Moderate to severe alkali stress (pH >9.4) caused a significant decline in turf quality and growth rate in Kentucky bluegrass. Soluble protein was unchanged in shoots, but decreased in roots as pH increased. The levels of amino acids was kept at the same level as control level at 4 days after treatment (DAT) in shoots, but greater at 7 DAT, when plants were subjected to severe (pH 10.3) alkali stress. The alkali stressed plants had a greater level of starch, water soluble carbohydrate and sucrose content, but lower level of fructose and glucose. Fructan and total non-structural carbohydrate (TNC) increased at 4 DAT and decreased at 7 DAT for alkali stressed plants. These results suggested that the decrease in fructose and glucose contributed to the growth reduction under alkali stress, while the increase in amino acids, sucrose and storage form of carbohydrate (fructan, starch) could be an adaptative mechanism in Kentucky bluegrass under alkali stress.

  • Content Type Journal Article
  • Pages 1-8
  • DOI 10.1007/s10646-012-0924-1
  • Authors
    • Pingping Zhang, Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, Hubei 430074, People’s Republic of China
    • Jinmin Fu, Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, Hubei 430074, People’s Republic of China
    • Longxing Hu, Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, Hubei 430074, People’s Republic of China

Quelle: Ecotoxicology (Browse Results) | 17 May 2012 | 5:16 pm CEST

Intraspecific competition increases toxicant effects in outdoor pond microcosms

Abstract  
Competition is a ubiquitous factor in natural populations and has been reported to alter the ecological impact of xenobiotics. We investigated conditions that mirror the natural variation of environmental factors. For this, different treatments were applied to 96 outdoor pond microcosms by shading the ponds and harvesting the communities. Then, the effect of esfenvalerate (0.03, 0.3, and 3 Î¼g/L) on populations of Daphnia spp. was investigated. The pesticide effect and the sensitivity of Daphnia spp. in the context of a zooplankton community was increased by intraspecific competition 11 days after contamination. This relationship was most pronounced at 0.03 and 0.3 Î¼g/L esfenvalerate, which were the concentrations that led to partial mortality. In contrast, interspecific interaction did not significantly alter the effect of the toxicant on Daphnia spp. Modelled concentration–response curves showed that the negative effects of the pesticide differed by a factor of up to 100 depending on the strength of intraspecific competition. In addition, a wider range of concentrations led to negative effects at high levels of intraspecific competition than at low levels. We argue that increased intraspecific competition reduces the availability of resources at the individual level and thereby increases the effect of contaminants. This knowledge about the interaction between competition and the response to toxicants is important in assessing the effects of these factors under field conditions.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0919-y
  • Authors
    • Saskia Knillmann, Department of System-Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany
    • Nathalie C. Stampfli, Department of System-Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany
    • Mikhail A. Beketov, Department of System-Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany
    • Matthias Liess, Department of System-Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany

Quelle: Ecotoxicology (Browse Results) | 10 May 2012 | 8:11 am CEST

Antimicrobial effects of commercial silver nanoparticles are attenuated in natural streamwater and sediment

Abstract  
Given the demonstrated antimicrobial properties of silver nanoparticles (AgNPs), and the key role that microorganisms play in performing critical ecosystem functions such as decomposition and nutrient cycling, there is growing concern that AgNP pollution may negatively impact ecosystems. We examined the response of streamwater and sediment microorganisms to commercially available 21 Â± 17 nm AgNPs, and compared AgNP impacts to those of dissolved-Ag added as AgNO3. We show that in streamwater, AgNPs and AgNO3 decreased respiration in proportion to dissolved-Ag concentrations at the end of the incubation (r2 = 0.78), while in sediment the only measurable effect of AgNPs was a 14 % decrease in sulfate concentration. This contrasts with the stronger effects of dissolved-Ag additions in both streamwater and sediment. In streamwater, addition of dissolved-Ag at a level equivalent to the lowest AgNP dose led to respiration below detection, a 55 % drop in phosphatase enzyme activity, and a 10-fold increase in phosphate concentration. In sediment, AgNO3 addition at a level equivalent to the highest AgNP addition led to a 34 % decrease in respiration, a 55 % increase in microbial biomass, and a shift in bacterial community composition. The results of this study suggest that, in similar freshwater environments, the short-term biological impacts of AgNPs on microbes are attenuated by the physical and chemical properties of streamwater and sediment.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0920-5
  • Authors
    • Benjamin P. Colman, Department of Biology, Duke University, Durham, NC, USA
    • Si-Yi Wang, Department of Biology, Duke University, Durham, NC, USA
    • Melanie Auffan, International Consortium for the Environmental Implications of NanoTechnology (iCEINT), CEREGE UMR 7330-CNRS/Aix-Marseille Université, Europôle de L’Arbois, 13545 Aix-en-Provence, France
    • Mark R. Wiesner, Civil and Environmental Engineering Department, Duke University, Durham, NC, USA
    • Emily S. Bernhardt, Department of Biology, Duke University, Durham, NC, USA

Quelle: Ecotoxicology (Browse Results) | 9 May 2012 | 7:53 am CEST

Toxicokinetic-toxicodynamic modelling of survival of Gammarus pulex in multiple pulse exposures to propiconazole: model assumptions, calibration data requirements and predictive power

Abstract  
Toxicokinetic-toxicodynamic (TKTD) models quantify the time-course of internal concentration, which is defined by uptake, elimination and biotransformation (TK), and the processes which lead to the toxic effects (TD). TKTD models show potential in predicting pesticide effects in fluctuating concentrations, but the data requirements and validity of underlying model assumptions are not known. We calibrated TKTD models to predict survival of Gammarus pulex in propiconazole exposure and investigated the data requirements. In order to assess the need of TK in survival models, we included or excluded simulated internal concentrations based on pre-calibrated TK. Adding TK did not improve goodness of fits. Moreover, different types of calibration data could be used to model survival, which might affect model parameterization. We used two types of data for calibration: acute toxicity (standard LC50, 4 d) or pulsed toxicity data (total length 10 d). The calibration data set influenced how well the survival in the other exposure scenario was predicted (acute to pulsed scenario or vice versa). We also tested two contrasting assumptions in ecotoxicology: stochastic death and individual tolerance distribution. Neither assumption fitted to data better than the other. We observed in 10-d toxicity experiments that pulsed treatments killed more organisms than treatments with constant concentration. All treatments received the same dose, i.e. the time-weighted average concentration was equal. We studied mode of toxic action of propiconazole and it likely acts as a baseline toxicant in G. pulex during 10-days of exposure for the endpoint survival.

  • Content Type Journal Article
  • Pages 1-13
  • DOI 10.1007/s10646-012-0917-0
  • Authors
    • Anna-Maija Nyman, Department of Environmental Toxicology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
    • Kristin Schirmer, Department of Environmental Toxicology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
    • Roman Ashauer, Department of Environmental Toxicology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland

Quelle: Ecotoxicology (Browse Results) | 5 May 2012 | 8:03 am CEST

Atorvastatin up-regulate toxicologically relevant genes in rainbow trout gills

Abstract  
There are large and increasing discharges of statins into the aquatic environment. Statins are cholesterol-lowering pharmaceuticals, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, an enzyme in the cholesterol synthesis pathway. Earlier studies have shown that statins will affect the expression of a range of genes in mammalian tissues and this group of pharmaceuticals has also been shown to affect membrane transporters. Changes in gene expression and ion transport in aquatic organisms may have dramatic consequences for the individual. The aim of the present study was to clarify whether waterborne exposure to a selected statin, atorvastatin, would affect gene expression in rainbow trout (Oncorhynchus mykiss) gill or liver or ion regulation in gills. Juvenile rainbow trout were exposed to two atorvastatin acid and atorvastatin lactone concentrations for 7 days (nominal concentrations 200 ng L−1 and 10 Î¼g L−1). The exposures caused up-regulated gene expression in gill, not liver, and only at the lowest concentration. Genes involved in membrane transport (pgp, mrp1), oxidative stress response (sod, mt), apoptosis (bax) and biotransformation (sult2b) were differentially expressed whereas the expression of genes involved in cholesterol biosynthesis (hmgr, fdps) or peroxisomal proliferation (ppar) were not affected. There were no significant changes in gill Na+/K+ ATPase activity following exposure to atorvastatin. The pattern of differentially expressed genes in rainbow trout gills differ from responses previously observed in mammalian tissues following statin exposure.

  • Content Type Journal Article
  • Pages 1-16
  • DOI 10.1007/s10646-012-0918-z
  • Authors
    • Kathrin Sabine Ellesat, Department of Biology, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, Norway
    • Tor Fredrik Holth, Department of Biology, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, Norway
    • Marcin WÅ‚odzimierz Wojewodzic, Department of Biology, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, Norway
    • Ketil Hylland, Department of Biology, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, Norway

Quelle: Ecotoxicology (Browse Results) | 4 May 2012 | 7:31 pm CEST

Effects of the fungicide metiram in outdoor freshwater microcosms: responses of invertebrates, primary producers and microbes

Abstract  
The ecological impact of the dithiocarbamate fungicide metiram was studied in outdoor freshwater microcosms, consisting of 14 enclosures placed in an experimental ditch. The microcosms were treated three times (interval 7 days) with the formulated product BAS 222 28F (Polyram®). Intended metiram concentrations in the overlying water were 0, 4, 12, 36, 108 and 324 Î¼g a.i./L. Responses of zooplankton, macroinvertebrates, phytoplankton, macrophytes, microbes and community metabolism endpoints were investigated. Dissipation half-life (DT50) of metiram was approximately 1–6 h in the water column of the microcosm test system and the metabolites formed were not persistent. Multivariate analysis indicated treatment-related effects on the zooplankton (NOECcommunity = 36 Î¼g a.i./L). Consistent treatment-related effects on the phytoplankton and macroinvertebrate communities and on the sediment microbial community could not be demonstrated or were minor. There was no evidence that metiram affected the biomass, abundance or functioning of aquatic hyphomycetes on decomposing alder leaves. The most sensitive populations in the microcosms comprised representatives of Rotifera with a NOEC of 12 Î¼g a.i./L on isolated sampling days and a NOEC of 36 Î¼g a.i./L on consecutive samplings. At the highest treatment-level populations of Copepoda (zooplankton) and the blue-green alga Anabaena (phytoplankton) also showed a short-term decline on consecutive sampling days (NOEC = 108 Î¼g a.i./L). Indirect effects in the form of short-term increases in the abundance of a few macroinvertebrate and several phytoplankton taxa were also observed. The overall community and population level no-observed-effect concentration (NOECmicrocosm) was 12–36 Î¼g a.i./L. At higher treatment levels, including the test systems that received the highest dose, ecological recovery of affected measurement endpoints was fast (effect period < 8 weeks).

  • Content Type Journal Article
  • Pages 1-20
  • DOI 10.1007/s10646-012-0909-0
  • Authors
    • Ronghua Lin, Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA, Wageningen, The Netherlands
    • Laura Buijse, Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA, Wageningen, The Netherlands
    • Mauricio R. Dimitrov, Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands
    • Peter Dohmen, BASF SE, Agricultural Center, APD/EE-L1425, Speyerer Str. 2, 67117 Limburgerhof, Germany
    • Sujitra Kosol, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, S10 2TN UK
    • Lorraine Maltby, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, S10 2TN UK
    • Ivo Roessink, Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA, Wageningen, The Netherlands
    • Jos A. Sinkeldam, Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA, Wageningen, The Netherlands
    • Hauke Smidt, Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands
    • René P. A. Van Wijngaarden, Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA, Wageningen, The Netherlands
    • Theo C. M. Brock, Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA, Wageningen, The Netherlands

Quelle: Ecotoxicology (Browse Results) | 4 May 2012 | 7:31 pm CEST

Effect of different spiking procedures on the distribution and toxicity of ZnO nanoparticles in soil

Abstract  
Due to the difficulty in dispersing some engineered nanomaterials in exposure media, realizing homogeneous distributions of nanoparticles (NP) in soil may pose major challenges. The present study investigated the distribution of zinc oxide (ZnO) NP (30 nm) and non-nano ZnO (200 nm) in natural soil using two different spiking procedures, i.e. as dry powder and as suspension in soil extract. Both spiking procedures showed a good recovery (>85 %) of zinc and based on total zinc concentrations no difference was found between the two spiking methods. Both spiking procedures resulted in a fairly homogeneous distribution of the ZnO particles in soil, as evidenced by the low variation in total zinc concentration between replicate samples (<12 % in most cases). Survival of Folsomia candida in soil spiked at concentrations up to 6,400 mg Zn kg−1 d.w. was not affected for both compounds. Reproduction was reduced in a concentration-dependent manner with EC50 values of 3,159 and 2,914 mg Zn kg−1 d.w. for 30 and 200 nm ZnO spiked as dry powder and 3,593 and 5,633 mg Zn kg−1 d.w. introduced as suspension. Toxicity of ZnO at 30 and 200 nm did not differ. We conclude that the ZnO particle toxicity is not size related and that the spiking of the soil with ZnO as dry powder or as a suspension in soil extract does not affect its toxicity to F. candida.

  • Content Type Journal Article
  • Pages 1-8
  • DOI 10.1007/s10646-012-0914-3
  • Authors
    • Pauline L. Waalewijn-Kool, Department of Animal Ecology, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
    • Maria Diez Ortiz, Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB, UK
    • Cornelis A. M. van Gestel, Department of Animal Ecology, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands

Quelle: Ecotoxicology (Browse Results) | 3 May 2012 | 9:37 am CEST

Grape marc extract acts as elicitor of plant defence responses

Abstract  
Plant protection based on novel alternative strategies is a major concern in agriculture to sustain pest management. The marc extract of red grape cultivars reveals plant defence inducer properties. Treatment with grape marc extract efficiently induced hypersensitive reaction-like lesions with cell death evidenced by Evans Blue staining of tobacco leaves. Examination of the infiltration zone and the surrounding areas under UV light revealed the accumulation of autofluorescent compounds. Both leaf infiltration and a foliar spray of the red grape extract on tobacco leaves induced defence gene expression. The PR1 and PR2 target genes were upregulated locally and systemically in tobacco plants following grape marc extract treatment. The grape extract elicited an array of plant defence responses making this natural compound a potential phytosanitary product with a challenging issue and a rather attractive option for sustainable agriculture and environmentally friendly practices.

  • Content Type Journal Article
  • Pages 1-9
  • DOI 10.1007/s10646-012-0908-1
  • Authors
    • Pascale Goupil, Clermont Université, Université Blaise Pascal, UMR 547 PIAF, BP 10448, 63000 Clermont-Ferrand, France
    • Razik Benouaret, Clermont Université, Université Blaise Pascal, UMR 547 PIAF, BP 10448, 63000 Clermont-Ferrand, France
    • Olivia Charrier, Clermont Université, Université Blaise Pascal, UMR 547 PIAF, BP 10448, 63000 Clermont-Ferrand, France
    • Alexandra ter Halle, Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, Equipe Photochimie, BP 10448, 63000 Clermont-Ferrand, France
    • Claire Richard, Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, Equipe Photochimie, BP 10448, 63000 Clermont-Ferrand, France
    • Boris Eyheraguibel, Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, Equipe Photochimie, BP 10448, 63000 Clermont-Ferrand, France
    • Denis Thiery, UMR 1065 Santé et Agroécologie du Vignoble, Institut des Sciences de la Vigne et du Vin, INRA BP 81, 33883 Villenave-d’Ornon Cedex, France
    • Gérard Ledoigt, Clermont Université, Université Blaise Pascal, UMR 547 PIAF, BP 10448, 63000 Clermont-Ferrand, France

Quelle: Ecotoxicology (Browse Results) | 1 May 2012 | 8:01 am CEST

The effects of glyphosate and aminopyralid on a multi-species plant field trial

Abstract  
In the United States, the US EPA has the responsibility for the registration of pesticides. For the protection of nontarget terrestrial plants this requires two simple greenhouse tests (seedling emergence and vegetative vigor), each done with ten species grown individually. Indications of unacceptable effects levels equivalent to environmental exposure can lead to field testing which is not well-defined. Our objective was to develop a regional field test that is simple, economical, geographically flexible and with endpoints of ecological significance and compare the results with the standard greenhouse tests. Three native Oregon plant species were grown together with an introduced species. The experiment was replicated at two locations and repeated for 3 years with glyphosate applied at 0, 0.01 (8.3 g/ha), 0.1 (83.2 g/ha), and 0.2 (166.4 g/ha) Ã— FAR (Field Application Rate of 832 gm/ha acid equivalent) and 2 years with aminopyralid applied at 0, 0.037 (4.6 g/ha), 0.136 (16.7 g/ha), and 0.5 (61.5 g/ha) Ã— FAR (123 g/ha acid equivalent). With glyphosate, plant height and volume decreased with increasing herbicide concentration for all species, and for nearly all farm Ã— year combinations. With aminopyralid, one species died at nearly all concentrations, sites and years, while the effects on the other three species were less pronounced and variable. The relative rank in glyphosate sensitivity among species in the field studies differed from the ranking from greenhouse studies, with Cynososurs echinatus the most sensitive in the field but Prunella vulgaris the most sensitive in the greenhouse. With aminopyralid, sensitivity generally was similar for all species in the greenhouse as in the field. The results suggest that a simple field test can be successfully designed to investigate the ecological effects of herbicides on plant communities and supplement information gained from greenhouse tests performed in controlled environments.

  • Content Type Journal Article
  • Pages 1-17
  • DOI 10.1007/s10646-012-0912-5
  • Authors
    • Thomas Pfleeger, US Environmental Protection Agency, Western Ecology Division, National Health and Environmental Effects Research Laboratory, 200 SW 35th St., Corvallis, OR 97333, USA
    • Matthew Blakeley-Smith, US Environmental Protection Agency, Western Ecology Division, National Health and Environmental Effects Research Laboratory, 200 SW 35th St., Corvallis, OR 97333, USA
    • George King, Dynamac Corporation, 200 SW 35th St., Corvallis, OR 97333, USA
    • E. Henry Lee, US Environmental Protection Agency, Western Ecology Division, National Health and Environmental Effects Research Laboratory, 200 SW 35th St., Corvallis, OR 97333, USA
    • Milton Plocher, Dynamac Corporation, 200 SW 35th St., Corvallis, OR 97333, USA
    • David Olszyk, US Environmental Protection Agency, Western Ecology Division, National Health and Environmental Effects Research Laboratory, 200 SW 35th St., Corvallis, OR 97333, USA

Quelle: Ecotoxicology (Browse Results) | 1 May 2012 | 8:01 am CEST

Zebrafish (Danio rerio) life-cycle exposure to chronic low doses of ethinylestradiol modulates p53 gene transcription within the gonads, but not NER pathways

Abstract  
Parental full life-cycle exposure to ethinylestradiol (EE2) significantly affects embryo development and survival. One of the possible mechanisms of action of EE2 may involve the impairment of an organism’s ability to repair DNA damage. DNA repair mechanisms have sophistically evolved to overcome DNA damaging hazards that threaten the integrity of the genome. In the present study, changes in the transcription levels of key genes involved in two of the most thoroughly studied DNA repair systems in mammals were evaluated in adult zebrafish (Danio rerio) gonad upon full life-cycle exposure to chronic environmentally low levels of EE2 (i.e., 0.5, 1 and 2 ng/L EE2). Real time PCR was used to analyse the expression levels of nucleotide excision repair genes (NER) as well as the tumor suppressor p53 and downstream selected effectors, i.e., p21 (cyclin-dependent kinase inhibitor), GADD45α (growth arrest and DNA damage induced 45, alpha), bax (bcl2-associated X protein) and p53 key regulator MDM2 (murine double minute 2 protein). NER genes transcription levels in gonads did not differ significantly among treatments. In contrast, the number of transcripts of p53 gene was significantly increased in male gonads at all EE2 exposure concentrations and in females at 1 ng/L EE2. Despite the increase in p53 transcripts, transcription levels of p21, GADD45α and bax genes were not affected upon EE2 treatment, whereas MDM2 gene expression significantly increased in females at the intermediate EE2 dose (1 ng/L). Overall, the present study indicate that chronic low levels of EE2 significantly modulates the transcription of p53, a key gene involved in DNA repair, particularly in male zebrafish gonads, which supports the hypothesis of an impact of EE2 in male gonad DNA repair pathways.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0905-4
  • Authors
    • J. Soares, Laboratory of Environmental Toxicology, CIMAR/CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal
    • L. Filipe C. Castro, Laboratory of Cellular, Molecular and Analytical Studies, CIMAR/CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal
    • M. A. Reis-Henriques, Laboratory of Environmental Toxicology, CIMAR/CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal
    • N. M. Monteiro, CEBIMED, FCS-UFP, Faculty of Health Sciences, University Fernando Pessoa, Oporto, Portugal
    • M. M. Santos, Laboratory of Environmental Toxicology, CIMAR/CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal

Quelle: Ecotoxicology (Browse Results) | 28 Apr 2012 | 7:59 am CEST

Biodiversity and structure of spider communities along a metal pollution gradient

Abstract  
The objective of the study was to determine whether long-term metal pollution affects communities of epigeal spiders (Aranea), studied at three taxonomic levels: species, genera, and families. Biodiversity was defined by three indices: the Hierarchical Richness Index (HRI), Margalef index (DM) and Pielou evenness index (J). In different ways the indices describe taxa richness and the distribution of individuals among taxa. The dominance pattern of the communities was described with four measures: number of dominant species at a site, percentage of dominant species at a site, average dominant species abundance at a site, and the share of the most numerous species (Alopecosa cuneata) at a site. Spiders were collected along a metal pollution gradient in southern Poland, extending ca. 33 km from zinc and lead smelter to an uncontaminated area. The zinc concentration in soil was used as the pollution index.The study revealed a significant effect of metal pollution on spider biodiversity as described by HRI for species (p = 0.039), genera (p = 0.0041) and families (p = 0.0147), and by DM for genera (p = 0.0259) and families (p = 0.0028). HRI correlated negatively with pollution level, while DM correlated positively. This means that although broadly described HRI diversity decreased with increasing pollution level, species richness increased with increasing contamination. Mesophilic meadows were generally richer. Pielou (J) did not show any significant correlations. There were a few evidences for the intermediate disturbance hypothesis: certain indices reached their highest values at moderate pollution levels rather than at the cleanest or most polluted sites.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0906-3
  • Authors
    • Sebatian Å»mudzki, Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, 30-387 Kraków, Poland
    • Ryszard Laskowski, Institute of Environmental Sciences, Jagiellonian University, ul. Gronostajowa 7, 30-387 Kraków, Poland

Quelle: Ecotoxicology (Browse Results) | 28 Apr 2012 | 7:59 am CEST

Effects of 1,1,1-trichloroethane on enzymatic activity and bacterial community in anaerobic microcosm form sequencing batch reactors

Abstract  
1,1,1-Trichloroethane (TCA), a major organic and groundwater contaminant, has very strong toxic effects on humans, plants and microorganisms. Effects of TCA on enzymatic activity and microbial diversity were investigated in the anaerobic sequencing batch reactor (ASBR) under methanogenic, nitrate-reducing, sulfate-reducing and benzene/toluene degrading conditions. The activities of three enzymes (lactate dehydrogenase, phosphatase and protease) were significantly decreased in the presence of 5 mg/L TCA. Within these three affected enzymes, phosphatase activity may serve as a noteworthy marker of bacterial toxicity. The activity of phosphatase was 0.2 U/L in methanogenic conditions with 5 mg/L TCA, which was 99% lower than the controls, and the enzyme activity was 18.6 U/L in methanogenic conditions with 1 mg/L TCA, which was 7% lower than the controls. DGGE profiles showed that TCA altered the bacterial community distribution and diversity obviously during the 21 day of TCA exposure. The enzyme activities decreased second lowest but TCA degrading strains Clostridium sp. DhR-2/LM-G01, Bacterial clone DCE25 and Bacterial clone DPHB06 were enriched in the methanogenic ASBR amended TCA.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0896-1
  • Authors
    • Hui Li, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Wei Zhang, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Lu Li, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Yong-Di Liu, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Kuang-Fei Lin, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Shu-Guang Lu, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Bo-Zhong Mu, State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Xiao-Ming Du, Department of Soil Pollution Control, Chinese Research Academy of Environmental Sciences, Beijing, 100012 People’s Republic of China
    • Qiang Lu, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Qian Zhang, State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Ting-Ting Shen, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Bing-Zhi Li, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Li-Ming Zhao, State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 People’s Republic of China
    • Yang-Yang Li, Shanghai Research Institute of Chemical Industry, Shanghai, 200062 People’s Republic of China

Quelle: Ecotoxicology (Browse Results) | 28 Apr 2012 | 7:59 am CEST

Short-term uptake of microcystin-LR by Coregonus lavaretus: GST activity and genotoxicity

Abstract  
In the present study, juvenile whitefish weighing 2 g were exposed by force-feeding to two ecologically relevant doses (0.05 and 0.5 Î¼g per fish) of microcystin-LR (MC-LR). Then over 96 h the MC uptake in fish liver and muscle was measured, as the activity of the detoxification enzyme glutathione S-transferase (GST) in the liver, and the genotoxicity impact on red blood cells. Results show that (1) the MC-LR equivalent concentrations increased for both doses and in both organs of whitefish with approximately threefold lower concentrations for the low dose compared to the high dose in both organs and threefold lower concentrations in the muscle compared to the liver for each dose (2) the liver GST activity increased during the first 48 h of exposure with fivefold higher GST activity for the highest dose at 48 h compared to control and (3) MC-LR leads to deoxyribonucleic acid strand breaks that were detected by the comet assay and shown to be partially repaired. This work demonstrates that European whitefish could be impacted by cyanobacteria toxins due to rapid microcystin uptake, especially in the context of chronic contamination, which can occur during long bloom episodes.

  • Content Type Journal Article
  • Pages 1-9
  • DOI 10.1007/s10646-012-0913-4
  • Authors
    • Benoît Sotton, INRA, UMR CARRTEL, 75 av. de Corzent, 74203 Thonon Les Bains, France
    • Alain Devaux, LEHNA, UMR 5023, ENTPE, Université de Lyon, 3 rue Maurice Audin, 69518 Vaulx en Velin Cedex, France
    • Nicolas Givaudan, INRA, UMR CARRTEL, 75 av. de Corzent, 74203 Thonon Les Bains, France
    • Jean Guillard, INRA, UMR CARRTEL, 75 av. de Corzent, 74203 Thonon Les Bains, France
    • Isabelle Domaizon, INRA, UMR CARRTEL, 75 av. de Corzent, 74203 Thonon Les Bains, France
    • Sylvie Bony, LEHNA, UMR 5023, ENTPE, Université de Lyon, 3 rue Maurice Audin, 69518 Vaulx en Velin Cedex, France
    • Orlane Anneville, INRA, UMR CARRTEL, 75 av. de Corzent, 74203 Thonon Les Bains, France

Quelle: Ecotoxicology (Browse Results) | 27 Apr 2012 | 7:54 am CEST

Direct and indirect effects of the glyphosate formulation Glifosato Atanor® on freshwater microbial communities

Abstract  
Glyphosate-based formulations are among the most widely used herbicides in the world. The effect of the formulation Glifosato Atanor® on freshwater microbial communities (phytoplankton, bacterioplankton, periphyton and zooplankton) was assessed through a manipulative experiment using six small outdoor microcosms of small volume. Three of the microcosms were added with 3.5 mg l−1 of glyphosate whereas the other three were left as controls without the herbicide. The treated microcosms showed a significant increase in total phosphorus, not fully explained by the glyphosate present in the Glifosato Atanor®. Therefore, part of the phosphorus should have come from the surfactants of the formulation. The results showed significant direct and indirect effects of Glifosato Atanor® on the microbial communities. A single application of the herbicide caused a fast increase both in the abundance of bacterioplankton and planktonic picocyanobacteria and in chlorophyll a concentration in the water column. Although metabolic alterations related to oxidative stress were induced in the periphyton community, the herbicide favored its development, with a large contribution of filamentous algae typical of nutrient-rich systems, with shallow and calm waters. An indirect effect of the herbicide on the zooplankton was observed due to the increase in the abundance of the rotifer Lecane spp. as a consequence of the improved food availability given by picocyanobacteria and bacteria. The formulation affected directly a fraction of copepods as a target. It was concluded that the Glifosato Atanor® accelerates the deterioration of the water quality, especially when considering small-volume water systems.

  • Content Type Journal Article
  • Pages 1-12
  • DOI 10.1007/s10646-012-0915-2
  • Authors
    • María Solange Vera, Laboratorio de Limnología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina
    • Eugenia Di Fiori, Laboratorio de Limnología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina
    • Leonardo Lagomarsino, Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB-INTECH), CC 164, 7130, Chascomús, Buenos Aires, Argentina
    • Rodrigo Sinistro, Laboratorio de Limnología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina
    • Roberto Escaray, Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (IIB-INTECH), CC 164, 7130, Chascomús, Buenos Aires, Argentina
    • María Mercedes Iummato, Laboratorio de Enzimología, Estrés Oxidativo y Metabolismo, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina
    • Angela Juárez, Laboratorio de Enzimología, Estrés Oxidativo y Metabolismo, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina
    • María del Carmen Ríos de Molina, Laboratorio de Enzimología, Estrés Oxidativo y Metabolismo, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina
    • Guillermo Tell, Laboratorio de Limnología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina
    • Haydée Pizarro, Laboratorio de Limnología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Ciudad de Buenos Aires, Argentina

Quelle: Ecotoxicology (Browse Results) | 27 Apr 2012 | 7:54 am CEST

Effects of the organophosphate fenthion for control of the red-billed quelea Quelea quelea on cholinesterase and haemoglobin concentrations in the blood of target and non-target birds

Abstract  
The red-billed quelea bird Quelea quelea is one of sub-Saharan Africa’s most damaging pests, attacking small-grain crops throughout semi-arid zones. It is routinely controlled by spraying its breeding colonies and roosts with organophosphate pesticides, actions often associated with detrimental effects on non-target organisms. Attributions of mortality and morbidity of non-targets to the sprays are difficult to confirm unequivocally but can be achieved by assessing depressions in cholinesterase activities since these are reduced by exposure to organophosphates. Here we report on surveys of birds caught before and after sprays that were examined for their blood cholinesterase activities to assess the extent to which these became depressed. Blood samples from birds were taken before and after sprays with fenthion against red-billed quelea in colonies or roosts, and at other unsprayed sites, in Botswana and Tanzania and analysed for levels of haemoglobin (Hb) and activities of whole blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Background activities of AChE, BChE and Hb concentrations varied with bird species, subspecies, mass, age and gender. Contrary to expectation, since avian erythrocytes are often reported to lack cholinesterases, acetylcholinesterase activities in pre-spray samples of adult birds were positively correlated with Hb concentrations. When these factors were taken into account there were highly significant declines (P < 0.0001) in AChE and BChE and increases in Hb after contact with fenthion in both target and non-target birds. BChE generally declined further (up to 87 % depression) from baseline levels than AChE (up to 83 % depression) but did so at a slower rate in a sample of quelea nestlings. Baseline activities of AChE and BChE and levels of Hb were higher in the East African subspecies of the red-billed quelea Q. q. aethiopica than in the southern African subspecies Q. q. lathamii, with the exception of BChE activities for adult males which were equivalent.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0911-6
  • Authors
    • Robert A. Cheke, Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB UK
    • Andrew N. McWilliam, The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH Scotland, UK
    • Collen Mbereki, Division of Plant Protection, Ministry of Agriculture, Gaborone, Botswana
    • Etienne van der Walt, ARC, Plant Protection Research Institute, Pretoria, South Africa
    • Boaz Mtobesya, Plant Health Services, Ministry of Agriculture Food Security and Cooperatives, Arusha, Tanzania
    • Richard N. Magoma, Plant Health Services, Ministry of Agriculture Food Security and Cooperatives, Arusha, Tanzania
    • Stephen Young, Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB UK
    • J. Patrick Eberly, EQM Research, 2814 Urwiler Ave., Cincinnati, OH 45211, USA

Quelle: Ecotoxicology (Browse Results) | 27 Apr 2012 | 7:54 am CEST

Antagonistic toxicity of arsenate and cadmium in a freshwater amphipod (Gammarus pulex)

Abstract  
Because toxicants rarely occur alone in the environment, a major challenge in risk assessment is to address the combined effects of chemicals on aquatic organisms. This work is aimed at investigating the joint toxicity action of binary mixtures of cadmium and arsenate on Gammarus pulex. Individuals were exposed during 240 h to four single arsenate or cadmium concentrations and binary mixtures of these metals according to a complete factorial plane. Observed mortality in binary mixtures was compared to observed mortality in single arsenate or cadmium exposures. In addition, interactive effects (antagonistic, additive or synergistic) were evaluated using a predictive model for the theoretically expected interactive effect of chemicals. For all the tested concentration combinations, we observed an antagonist ‘between-metals’ interaction on G. pulex mortality. This antagonistic effect was more marked for the lowest than for the highest (i.e. 1502.0 Î¼gAsV L−1 and 28.5 Î¼gCd L−1) tested concentrations of individual metals in binary mixtures. Metal concentrations in body tissues were evaluated and were significantly lower in binary mixtures than in single metal exposures at similar concentration, especially for combinations corresponding to the highest concentrations of both metals (1502.0 Î¼gAsV L−1 and 28.5 Î¼gCd L−1). Results were discussed in terms of (1) mechanisms of uptake and bioconcentration and (2) relationships between metal concentration in gammarid body and observed toxicity.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0916-1
  • Authors
    • Céline Vellinger, Laboratoire des Interactions Ecotoxicologie Biodiversité Ecosystèmes (LIEBE), Université de Lorraine (UDL), CNRS UMR 7146, Campus Bridoux, Rue du Général Delestraint, 57070 Metz, France
    • Marc Parant, Laboratoire des Interactions Ecotoxicologie Biodiversité Ecosystèmes (LIEBE), Université de Lorraine (UDL), CNRS UMR 7146, Campus Bridoux, Rue du Général Delestraint, 57070 Metz, France
    • Philippe Rousselle, Laboratoire des Interactions Ecotoxicologie Biodiversité Ecosystèmes (LIEBE), Université de Lorraine (UDL), CNRS UMR 7146, Campus Bridoux, Rue du Général Delestraint, 57070 Metz, France
    • Philippe Usseglio-Polatera, Laboratoire des Interactions Ecotoxicologie Biodiversité Ecosystèmes (LIEBE), Université de Lorraine (UDL), CNRS UMR 7146, Campus Bridoux, Rue du Général Delestraint, 57070 Metz, France

Quelle: Ecotoxicology (Browse Results) | 26 Apr 2012 | 8:26 am CEST

DNA damage and oxidative stress induced by endosulfan exposure in zebrafish (Danio rerio)

Abstract  
Endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzo-dioxathiepin-3-oxide), an organochlorine pesticide, is prevalently used all around the world. It is considered to be a new candidate for the persistent organic pollutants group. Endosulfan residues in the environment may cause serious damage to ecosystems, especially in aquatic environments. The present study was conducted to investigate the effect of endosulfan on antioxidant enzymes [catalase (CAT) and superoxide dismutase (SOD)], reactive oxygen species (ROS) generation and DNA damage in zebrafish. Male and female zebrafish were separated and exposed to a control solution and four concentrations of endosulfan (0.01, 0.1, 1, and 10 Î¼g L−1) and were sampled after 7, 14, 21, and 28 days. It is noteworthy that the present research explored the correlation among the three indicators induced by endosulfan. Low endosulfan concentrations (0.01 Î¼g L−1) induced a slight increase of SOD and CAT activity, which kept ROS in a stable level. High endosulfan concentration (10 Î¼g L−1) induced excessive ROS production which exceeded the capacity of the cellular antioxidants and exhausted the enzyme including CAT and SOD. The DNA damage of zebrafish was evaluated by single-cell gel electrophoresis and was enhanced with increasing endosulfan concentration. In conclusion, the present study showed that endosulfan (0.01–10 Î¼g L−1) has toxic effects on zebrafish.

  • Content Type Journal Article
  • Pages 1-8
  • DOI 10.1007/s10646-012-0907-2
  • Authors
    • Bo Shao, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Lusheng Zhu, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Miao Dong, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Jun Wang, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Jinhua Wang, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Hui Xie, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Qingming Zhang, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Zhongkun Du, College of Resources and Environment, Key Laboratory of Agricultural Environment in Universities of Shandong, Shandong Agricultural University, 61 Daizong Road, Taian, 271018 China
    • Shaoyuan Zhu, College of Marine Life Sciences, Ocean University of China, Qingdao, 266109 China

Quelle: Ecotoxicology (Browse Results) | 26 Apr 2012 | 8:26 am CEST

Use of polar organic chemical integrative samplers to assess the effects of chronic pesticide exposure on biofilms

Abstract  
The responses of aquatic organisms to chronic exposure to environmental concentrations of toxicants, often found in mixtures, are poorly documented. Here passive sampler extracts were used in experimental contamination of laboratory channels, to investigate their effects on natural biofilm communities. A realistic mixture of pesticides extracted from Polar Organic Chemical Integrative Samplers was used to expose biofilms in laboratory channels to total pesticide concentrations averaging 0.5 Â± 0.1 Î¼g l−1. The level of exposure was representative of field conditions in terms of relative proportions of the substances but the exposure concentration was not maintained (decreasing concentrations between contamination occasions). The impact on the structural as well as the functional characteristics of the autotrophic and heterotrophic components was determined, using biofilm grown in uncontaminated conditions (reference site) and in sites exposed to pesticides (contaminated site). The exposure imposed did not significantly modify the structure or functions of reference biofilms, nor did it modify tolerance as measured by mixture EC50 (EC50 mix). In contrast, the communities from the more contaminated downstream section lost tolerance following decreased dose exposure, but community composition remained fairly stable. Overall, these results indicate that low levels of contamination did not lead to strong changes in community structure, and 14-day changes in tolerance seemed to depend mainly on physiological adaptation, suggesting that other environmental factors or longer-lasting processes prevailed. This study reports the first attempt to use passive sampler extracts as a realistic composite contaminant for experimental exposure of biofilms, with promising perspectives in further ecotoxicology studies.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0910-7
  • Authors
    • Soizic Morin, Irstea, UR REBX, 50 Avenue de Verdun, 33612 Cestas Cedex, France
    • Stéphane Pesce, Irstea, UR MALY, 3 Bis Quai Chauveau–CP220, 69336 Lyon, France
    • Sandra Kim-Tiam, Irstea, UR REBX, 50 Avenue de Verdun, 33612 Cestas Cedex, France
    • Xavier Libert, Irstea, UR REBX, 50 Avenue de Verdun, 33612 Cestas Cedex, France
    • Marina Coquery, Irstea, UR MALY, 3 Bis Quai Chauveau–CP220, 69336 Lyon, France
    • Nicolas Mazzella, Irstea, UR REBX, 50 Avenue de Verdun, 33612 Cestas Cedex, France

Quelle: Ecotoxicology (Browse Results) | 25 Apr 2012 | 8:22 am CEST

Plants as models for chromium and nickel risk assessment

Abstract  
The adverse effects of Cr(III), Cr(VI), and Ni(II) expressed as root and shoot growth inhibition, metal accumulation and translocation throughout plants, and genotoxicity study were examined. To examine phytoxicity and metal accumulation, Vicia sativa, Raphanus sativus, Zea mays and Sinapis alba plants were used. Except for S. alba root growth inhibition, Ni had the strongest inhibitory effect on root and shoot growth. The inhibitory rank order based on IC50 values was Ni(II) > Cr(VI) > Cr(III). Z. mays was the least sensitive to all metals. While the accumulation of Cr was higher in the roots than the upper plant parts, Ni transport to shoots was at least two times higher than that of Cr. The highest accumulation of Cr was found in Z. mays and that of Ni in V. sativa and Z. mays roots. For all plants, the translocation factor was higher for Cr(VI) than for Cr(III). The translocation factor for Ni was several times higher than those of Cr. For mutagenicity assay, root tips of V. sativa, R. sativus and Z. mays were used. All metals exerted a significant increase of chromosomal aberrations and the rank order of aberrations was: Cr(VI) > Ni(II) > Cr(III). Genotoxic effects of metals were also determined by analysis of micronuclei frequency in the pollen tetrads of Tradescantia plants. None of metals significantly stimulated micronuclei frequency and the genotoxic effect decreased in the following order: Cr(VI) â‰¥ Ni(II) > Cr(III).

  • Content Type Journal Article
  • Pages 1-8
  • DOI 10.1007/s10646-012-0901-8
  • Authors
    • A. FargaÅ¡ová, Department of Ecosozology and Physiotactics, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, 842 15 Bratislava, Slovakia

Quelle: Ecotoxicology (Browse Results) | 24 Apr 2012 | 10:19 am CEST

Decomposition analysis of LTREs may facilitate the design of short-term ecotoxicological tests

Abstract  
This study compared two methods, based on re-analyzed data from a partly published life table response experiment (LTRE), to help determine the optimal approach for designing ecotoxicological assessments. The 36-day LTRE data recorded the toxic effects of cadmium (Cd) and imidacloprid, alone and in combination, on the reproduction and survivorship of aphids (Acyrthosiphon pisum Harris). We used this data to construct an age-classified matrix model (six age classes, each 6 days long) to estimate aphid population growth rate (λ) under each treatment. For each treatment, an elasticity analysis and a demographic decomposition analysis were performed, and results were compared. Despite different results expected from the two toxicants, the elasticity values were very similar. The elasticity of λ with respect to survival was highest in the first age class, and that with respect to fertility was highest in the second age class. The demographic decomposition analysis examined how changes in life-history traits contributed to differences in λ between control and treated populations (Δλ). This indicated that the most important contributors to Δλ were the differences in survival (resulting from both demographic sensitivity and toxicity) in the first and the second age classes of aphids and differences in fertility in the third and the fourth age classes. Additionally, the toxicants acted differently. Cd reduced Δλ by impairing fertility at third age class and reducing survivorship from the second to the third age class. Imidacloprid mostly reduced survivorship at the first and second age classes. The elasticity and decomposition analyses showed different results, because these methods addressed different questions about the interaction of organism life history and sensitivity to toxicants. This study indicated that the LTRE may be useful for designing individual-level ecotoxicological experiments that account for both the effects of the toxicant and the demographic sensitivity of the organism.

  • Content Type Journal Article
  • Pages 1-9
  • DOI 10.1007/s10646-012-0904-5
  • Authors
    • Natnael T. Hamda, Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
    • Dragan M. Jevtić, Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
    • Ryszard Laskowski, Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland

Quelle: Ecotoxicology (Browse Results) | 23 Apr 2012 | 2:53 pm CEST

Acute toxicity of three strobilurin fungicide formulations and their active ingredients to tadpoles

Abstract  
Fungicide applications in the United States have increased tenfold in the last 5 years. Formulations and active ingredients (AIs) have been demonstrated to cause acute mortality to amphibian life stages. However, there has been little to no discrimination between the toxicity of fungicide formulations and their AIs. Therefore, we compared the acute toxicity of the active ingredients and formulations of the fungicides Headline®, Stratego®, and Quilt® using Bufo cognatus tadpoles exposed to four concentrations and a control. All fungicides, including AIs and formulations, demonstrated toxicity to tadpoles, with Headline® and Stratego® causing 100 % mortality at the highest concentrations. Exposure to Quilt® formulation and its AIs resulted in 50–60 % tadpole mortality. Overall, toxicity was comparable between AIs and formulations for all fungicides and concentrations, with the exception of Headline® at 5 Î¼g/L, where formulation exposure resulted in 79 % mortality versus no mortality from exposure to the AI. Results suggest the AIs are responsible for most mortality for Quilt® and Stratego®. Results for Headline® however suggest that although the AI is toxic to tadpoles at environmentally relevant concentrations, adjuvant(s) in the Headline® formulation also contribute to mortality, making it the most toxic of the fungicides studied.

  • Content Type Journal Article
  • Pages 1-7
  • DOI 10.1007/s10646-012-0899-y
  • Authors
    • Emily A. Hooser, Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA
    • Jason B. Belden, Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA
    • Loren M. Smith, Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA
    • Scott T. McMurry, Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA

Quelle: Ecotoxicology (Browse Results) | 18 Apr 2012 | 8:22 am CEST

Divergent teratogenicity of agonists of retinoid X receptors in embryos of zebrafish (Danio rerio)

Abstract  
Zebrafish (Danio rerio) embryos were comparably exposed to seven known agonists of retinoid X receptors (RXRs) including two endogenous compounds (9-cis-retinoic acid and docosahexaenoic acid), four man-made selective ligands (LGD1069, SR11237, fluorobexarotene and CD3254), and a biocide (triphenyltin). The dominant phenotypes of malformation were sharp mouths and small caudal fins in 1 mg/L SR11237-treated group after 5 days exposure. 9-cis-retinoic acid and LGD1069 induced multiple malformations including small eyes, bent notochords, reduced brain, enlarged proctodaems, absence of fins, short tails and edema after 5 days exposure. Fluorobexarotene and CD3254 induced similar phenotypes of malformations after 5 days exposure at low concentration (20 Î¼g/L) to those after the 1st d exposure at high concentrations (50 and 100 Î¼g/L). Triphenlytin induced multiple malformations including deformed eyes, bent notochords, bent tails, and edema in hearts after 5 days exposure at concentrations of 1–10 Î¼g Sn/L. In contrast, no discernible malformations were observed in triphenlytin-treated groups after each separate day exposure. These agonists not only showed different ability of teratogenicity but also induced different phenotypes of malformation in zebrafish embryos. In addition, the sensitive stages of zebrafish embryos were different in response to these agonists. Therefore, our results suggest that the agonists of RXRs had divergent teratogenicity in zebrafish embryos.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0900-9
  • Authors
    • Huahong Shi, State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062 China
    • Pan Zhu, Key Laboratory of Urbanization and Ecological Restoration, Department of Environmental Science, East China Normal University, Shanghai, 200062 China
    • Zhi Sun, Key Laboratory of Urbanization and Ecological Restoration, Department of Environmental Science, East China Normal University, Shanghai, 200062 China
    • Bo Yang, Key Laboratory of Urbanization and Ecological Restoration, Department of Environmental Science, East China Normal University, Shanghai, 200062 China
    • Liang Zheng, State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062 China

Quelle: Ecotoxicology (Browse Results) | 17 Apr 2012 | 8:23 am CEST

Effects of organic pollutants on Eobania vermiculata measured with five biomarkers

Abstract  
In the present study, the effect of organic pollution on land snails Eobania vermiculata was investigated. Five pollution biomarkers (neutral red retention assay, morphometry of lysosomes and neutral lipids, acetylcholinesterase activity and metallothioneins content, were applied on tissues of the land snails. The results showed intense differentiations between the snails treated with organic pollutants and the control ones, as indicated by the results obtained. Statistically significant correlations among the results obtained emphasize the usefulness of these biomarkers.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0902-7
  • Authors
    • A. Itziou, Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
    • V. K. Dimitriadis, Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece

Quelle: Ecotoxicology (Browse Results) | 17 Apr 2012 | 8:23 am CEST

Indicators of environmental stress: cellular biomarkers and reproductive responses in the Sydney rock oyster (Saccostrea glomerata)

Abstract  
We measured a suite of common biomarker responses for the first time in the Sydney rock oyster Saccostrea glomerata to evaluate their utility as biological effects measures for pollution monitoring. To examine the relationship between biomarker responses and population level effects, fertilisation and embryo development assays were also conducted. Adult oysters were deployed in two contaminated estuaries and a reference estuary in Sydney, Australia. The concentrations of various contaminants (metals and polycyclic aromatic hydrocarbon, PAHs) were quantified in oyster’s tissue from each site and both metals and total PAHs were significantly elevated in contaminated estuaries relative to the reference estuary. Lysosomal membrane destabilisation, lipid peroxidation levels and glutathione (GSH) concentrations were measured in the digestive gland of oysters. Of all biomarkers measured, lysosomal membrane destabilisation proved to be the most useful indicator of oysters facing anthropogenic stress and we suggest this may be an especially useful biomarker for incorporation into local environmental monitoring programs. Moreover, lysosomal membrane destabilisation showed good correlations with fertilisation, normal embryo development and estuary status. GSH and lipid peroxidation were not as valuable for distinguishing between estuaries exposed to differing levels of anthropogenic stress, but did provide additional valuable information regarding overall health status of the oysters.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0895-2
  • Authors
    • Katelyn J. Edge, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
    • Emma L. Johnston, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
    • Anthony C. Roach, Centre for Ecotoxicology, NSW Office of Environment and Heritage, Lidcombe, NSW, Australia
    • Amy H. Ringwood, Department of Biology, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA

Quelle: Ecotoxicology (Browse Results) | 17 Apr 2012 | 8:23 am CEST

Are the toxic sediments deposited at Flix reservoir affecting the Ebro river biota? Purple heron eggs and nestlings as indicators

Abstract  
The Flix reservoir, in the low course of the Ebro River, contains thousands of tons of polluted sediments, accumulated from the activities of a chemical factory. An ongoing project is working toward removing these pollutants. Piscivore birds like the purple heron (Ardea purpurea) may be useful bioindicators, so eggs and nestling feathers were sampled during the 2006–2008 breeding seasons at three localities: a reference site situated upstream and two potentially affected by the toxic muds; one at the focal area and one at a distal area, the Ebro Delta. The samples were analyzed for isotopic signatures of 15N and 13C and concentrations of heavy metals and selenium. Baseline nitrogen signatures were higher in riverine sites than in the delta. Nitrogen together with carbon signatures adequately discriminated riverine and deltaic ecosystems. Mercury levels are highly influenced by the polluted sediments at Flix and pose potential risks for the birds, as they are among the highest ever recorded in heron species. Selenium and copper concentrations probably derive from other sources. Except for mercury, heavy metals and selenium levels were below toxic levels. Purple heron eggs and nestling feathers have demonstrated their usefulness as bioindicators for pollution in the river biota; feathers in particular show pollutant impacts on a strict local basis. A long series of study years is necessary in dynamic ecosystems such as this, so continued monitoring of the heron population at Flix is advisable to trace the effects of the toxic muds, particularly during their removal, because of the high levels of mercury detected.

  • Content Type Journal Article
  • Pages 1-12
  • DOI 10.1007/s10646-012-0893-4
  • Authors
    • Javier Cotín, Department Biologia Animal, Facultat de Biologia, Univesitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
    • Manuel García-Tarrasón, Department Biologia Animal, Facultat de Biologia, Univesitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
    • Lluis Jover, Department Salut Pública, Facultat de Medicina, Universitat de Barcelona, Casanova 143, 08036 Barcelona, Spain
    • Carolina Sanpera, Department Biologia Animal, Facultat de Biologia, Univesitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain

Quelle: Ecotoxicology (Browse Results) | 17 Apr 2012 | 8:23 am CEST

Differential genotoxicity of Roundup® formulation and its constituents in blood cells of fish (Anguilla anguilla): considerations on chemical interactions and DNA damaging mechanisms

Abstract  
It has been widely recognized that pesticides represent a potential threat in aquatic ecosystems. However, the knowledge on the genotoxicity of pesticides to fish is still limited. Moreover, genotoxic studies have been almost exclusively focused on the active ingredients, whereas the effect of adjuvants is frequently ignored. Hence, the present study addressed the herbicide Roundup®, evaluating the relative contribution of the active ingredient (glyphosate) and the surfactant (polyethoxylated amine; POEA) to the genotoxicity of the commercial formulation on Anguilla anguilla. Fish were exposed to equivalent concentrations of Roundup® (58, 116 Î¼g L−1), glyphosate (17.9, 35.7 Î¼g L−1) and POEA (9.3, 18.6 Î¼g L−1), during 1 and 3 days. The comet assay was applied to blood cells, either as the standard procedure, or with an extra step involving DNA lesion-specific repair enzymes in an attempt to clarify DNA damaging mechanisms. The results confirmed the genotoxicity of Roundup®, also demonstrating the genotoxic potential of glyphosate and POEA individually. Though both components contributed to the overall genotoxicity of the pesticide formulation, the sum of their individual effects was never observed, pointing out an antagonistic interaction. Although POEA is far from being considered biologically inert, it did not increase the risk associated to glyphosate when the two were combined. The analysis of oxidatively induced breaks suggested that oxidation of DNA bases was not a dominant mechanism of damage. The present findings highlighted the risk posed to fish populations by the assessed chemicals, jointly or individually, emphasizing the need to define regulatory thresholds for all the formulation components and recommending, in particular, the revision of the hazard classification of POEA.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0892-5
  • Authors
    • S. Guilherme, Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
    • M. A. Santos, Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
    • C. Barroso, Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
    • I. Gaivão, CECAV and Department of Genetics and Biotechnology, Trás-os-Montes and Alto Douro University, 5001-801 Vila Real, Portugal
    • M. Pacheco, Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal

Quelle: Ecotoxicology (Browse Results) | 17 Apr 2012 | 8:23 am CEST

Cyanobacteria-blooming water samples from Lake Taihu induce endoplasmic reticulum stress in liver and kidney of mice

Abstract  
To investigate whether endoplasmic reticulum (ER) stress was involved in apoptosis induced by cyanobacteria-blooming water, healthy male ICR mice were fed with water samples from cyanobacteria-blooming regions of Lake Taihu (China), including Meiliang Bay (M1 and M2), central lake region (H), macrophyte-dominated Xukou Bay (X), and tap water (control group) for three consecutive months. Hepatic and renal mRNA and protein expression of ER stress signaling molecules were measured with quantitative real-time PCR and western blotting. Compared to macrophyte-dominated and control water samples, cyanobacteria-blooming water changed hepatic ER stress signaling molecules. M1 water treatment increased the mRNA and protein levels of glucose regulation protein 78 (GRP78) and C/EBP homologous protein (CHOP), and decreased the mRNA levels of B-cell lymphoma 2 (Bcl-2). M2 water treatment up-regulated GRP78 mRNA and protein expression, whereas H water treatment up-regulated mRNA and protein expression of GRP78 and caspase-12. Cyanobacteria-blooming water exposure also changed mRNA and protein expression of ER stress signaling molecules in the kidneys. M1 water exposure up-regulated GRP78 mRNA and protein expression and CHOP mRNA expression, whereas M2 water treatment up-regulated caspase-12 and Bcl-2 mRNA expression. M1 and M2 cyanobacteria-blooming water exposure significantly increased relative liver weights, and induced hepatic cell apoptosis. However, cyanobacteria-blooming water treatment did not change kidney weights, and did not induce renal apoptosis compared to macrophyte-dominated and control water samples. Hence, cyanobacteria-blooming water induces hepatic apoptosis via ER stress, and ER stress may play an important role in the apparent anti-apoptotic effects on renal cells exposed to cyanobacteria-blooming water.

  • Content Type Journal Article
  • Pages 1-9
  • DOI 10.1007/s10646-012-0903-6
  • Authors
    • Wendi Qin, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210046 People’s Republic of China
    • Liuyan Yang, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210046 People’s Republic of China
    • Xuxiang Zhang, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210046 People’s Republic of China
    • Zongyao Zhang, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210046 People’s Republic of China
    • Lizhi Xu, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, 22 Hankou Road, Nanjing, 210093 People’s Republic of China
    • Jun Wu, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210046 People’s Republic of China
    • Jing An, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210046 People’s Republic of China
    • Yaping Wang, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, 22 Hankou Road, Nanjing, 210093 People’s Republic of China

Quelle: Ecotoxicology (Browse Results) | 17 Apr 2012 | 8:23 am CEST

Hydrogen peroxide induces adaptive response and differential gene expression in human embryo lung fibroblast cells

Abstract

Hydrogen peroxide (H2O2), a substance involved in cellular oxidative stress, has been observed to induce an adaptive response, which is characterized by a protection against the toxic effect of H2O2 at higher concentrations. However, the molecular mechanism for the adaptive response remains unclear. In particular, the existing reports on H2O2-induced adaptive response are limited to animal cells and human tumor cells, and relatively normal human cells have never been observed for an adaptive response to H2O2. In this study, a human embryo lung fibroblast (MRC-5) cell line was used to model an adaptive response to H2O2, and the relevant differential gene expressions by using fluoro mRNA differential display RT-PCR. The results showed significant suppression of cytotoxicity of H2O2 (1100 μM, 1 h) after pretreatment of the cells with H2O2 at lower concentrations (0.088–8.8 μM, 24 h), as indicated by cell survival, lactate dehydrogenase release, and the rate of apoptotic cells. Totally 60 mRNA components were differentially expressed compared to untreated cells, and five of them (sizing 400–600 bp) which demonstrated the greatest increase in expression were cloned and sequenced. They showed identity with known genes, such as BCL-2, eIF3S5, NDUFS4, and RPS10. Real time RT-PCR analysis of the five genes displayed a pattern of differential expression consistent with that by the last method. These five genes may be involved in the induction of adaptive response by H2O2 in human cells, at least in this particular cell type. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 7 Apr 2012 | 2:22 pm CEST

Sediment organic tin contamination promotes impoverishment of non-biting midge species communities in the Archipelago Sea, S-W Finland

Abstract  
Chironomid species are a vital component in many benthic and terrestrial food webs; they have an important role in the detritus cycle, and are an important source of food for many species. We studied how tributyltin (TBT) in brackish water sediments affect the composition of chironomid species communities. Emergence traps were used at selected sites on a TBT gradient in the Archipelago Sea, S-W Finland. Increased sediment TBT concentration was associated with significant chironomid species turnover, which in turn was related to decreased species diversity (number of species and genera). However, the overall number of individuals did not decrease markedly with increasing TBT contamination. This suggests that the ecological role of chironomids in the food web may be preserved even under severe impoverishment of the chironomid community due to organic tin contamination. The increased prevalence of more TBT tolerant species can potentially lead to a transport of organic tin compounds between aquatic and terrestrial food webs. Furthermore, the reduced diversity of an ecologically influential group might lower the resistance of the entire food web to other environmental hazards and perturbations.

  • Content Type Journal Article
  • Pages 1-12
  • DOI 10.1007/s10646-012-0887-2
  • Authors
    • T. Lilley, Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland
    • L. Ruokolainen, Department of Biosciences, Helsinki University, P.O. Box 65, 00014 Helsinki, Finland
    • E. Vesterinen, Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland
    • L. Paasivirta, Ruuhikoskenkatu 17 B 5, 24240 Salo, Finland
    • K. Norrdahl, Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland

Quelle: Ecotoxicology (Browse Results) | 5 Apr 2012 | 5:47 pm CEST

Differential transcription of heat shock protein 90 (HSP90) in the dinoflagellate Prorocentrum minimum by copper and endocrine-disrupting chemicals

Abstract  
The dinoflagellate algae survive variations in water temperature as well as sudden exposures to toxic substances; heat shock proteins (HSPs) seem to function as part of their cell survival strategy. In the present study, we determined the complete open reading frame (ORF) of HSP90 gene in the dinoflagellate Prorocentrum minimum (PmHSP90), and examined the expression levels of the gene after exposure to thermal stressors, copper metal, and endocrine-disrupting chemicals, including bisphenol A (BPA) and polychlorinated biphenyl (PCB). The complete ORF of PmHSP90 was 2,130-bp long, encoding a 709-amino acid-long polypeptide (81.62 kDa), and bearing characteristics of the HSP90 family and conserved domains. Real-time (RT)-PCR analyses revealed different expression patterns after exposure to heat, metals, and chemicals. The expression of PmHSP90 was significantly upregulated by increased thermal stresses, with the highest changes of 2.4-fold and 1.9-fold occurring after 24 h at 25 Â°C and 30 Â°C, respectively. The gene expression dramatically increased (2.1 to 8.9-fold changes) with increasing concentrations of copper (one-way ANOVA, P < 0.01). Treatment with BPA or PCB, however, did not induce significant changes in PmHSP90 expression. These data suggest that the dinoflagellate HSP90 responds to thermal stressors, but may differentially respond to toxic substances such as metals and endocrine-disrupting chemicals.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0898-z
  • Authors
    • Ruoyu Guo, Department of Green Life Science, Sangmyung University, Seoul, 110-743 Korea
    • Jang-Seu Ki, Department of Green Life Science, Sangmyung University, Seoul, 110-743 Korea

Quelle: Ecotoxicology (Browse Results) | 5 Apr 2012 | 8:36 am CEST

Recovery potential of periphytic biofilms translocated in artificial streams after industrial contamination (Cd and Zn)

Abstract  
Metal wastes can significantly disturb aquatic communities, particularly photosynthetic organisms, the main primary producers in freshwater running ecosystems. In this study, biofilms and diatoms were used as bioindicators to characterize the kinetics of biofilm recovery. An experimental decontamination study was conducted under laboratory conditions, after biofilm colonisation at a site subject to discharge of industrial metals (Zn and Cd) and in parallel at an upstream site, metal-free, considered as a control. After 24 days of colonisation, biofilms were translocated and maintained in the laboratory for 56 days under clean conditions (control and decontamination) or metal contamination. Various tests were conducted from the community level—measures of metal bioaccumulation, cell densities and taxonomic investigations, to the individual level—measures of teratological forms. After 56 days of decontamination, Zn and Cd concentrations in decontaminated biofilms showed a sharp decline, respectively ranging from 6.7 Â± 2 to 4 Â± 2.5 mg Zn g−1 DW and from 207.6 Â± 24.5 to 45.4 Â± 9.9 Î¼g Cd g−1 DW. However, at the end of the experiment bioaccumulations remained significantly higher than concentrations in control biofilms. Despite a diatom evolution in biofilm assemblages, taxonomic inventories did not demonstrate a complete restoration of diatom communities in biofilms under decontamination conditions compared with controls, since metal-resistant species initially present after colonisation at the contaminated site, such as Eolimna minima, persisted in high abundance in decontaminated biofilms. Biofilms kept under metal pressure showed very high bioaccumulation capacities and a sharp decline of species diversity which allowed identification of some resistant species. Regarding these first results on the behaviour of diatom biofilms under experimental decontamination conditions, improvement of the natural hydrosystem’s chemical state appears quickly, but an eventual return to good ecological status appears delayed, with the persistence of metal-tolerant species even after 56 days.

  • Content Type Journal Article
  • Pages 1-12
  • DOI 10.1007/s10646-012-0894-3
  • Authors
    • Adeline Arini, Université Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France
    • Agnès Feurtet-Mazel, Université Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France
    • Régine Maury-Brachet, Université Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France
    • Oleg S. Pokrovsky, Laboratoire Geoscience and Environment Toulouse (GET) UMR 5563, CNRS OMP-Université Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France
    • Michel Coste, Cemagref/Irstea, UR REBX, 50 Avenue de Verdun, 33612 Cestas, France
    • François Delmas., Cemagref/Irstea, UR REBX, 50 Avenue de Verdun, 33612 Cestas, France

Quelle: Ecotoxicology (Browse Results) | 5 Apr 2012 | 8:36 am CEST

A metabolomics based test of independent action and concentration addition using the earthworm Lumbricus rubellus

Abstract  
A major challenge in ecotoxicology is to understand the effects of multiple toxicants on organisms. Here we assess the effects on survival, weight change, cocoon production and metabolism caused by exposure to two similarly acting (imidacloprid/thiacloprid) and two dissimilarly acting (chlorpyrifos/Nickel) chemicals on the earthworm Lumbricus rubellus. We assessed the standard models of concentration addition (CA) and independent action (IA), in conjunction with a metabolomics based approach to elucidate mechanisms of effect. For imidacloprid and thiacloprid the reproductive effects indicated probable additivity. Although this suggests joint effects through a similar mechanism, metabolite changes for each pesticide actually indicated distinct effects. Further, earthworms exposed to a 0.5 toxic unit equitoxic mixture demonstrated metabolic effects intermediate between those for each pesticide, indicating a non-interactive, independent joint effect. For higher effect level mixtures (1 and 1.5 toxic units), metabolite changes associated with thiacloprid exposure began to dominate. The metabolomic effects of the two dissimilarly acting chemicals were distinct, confirming separate modes of action and both proved more toxic than anticipated from previous studies. In the mixtures, phenotypic effects were in accordance with IA estimates, while metabolite changes were dominated by Ni effects, even though chlorpyrifos contributed most to reproductive toxicity. This could be attributed to the greater systematic effect of Ni when compared to the more specifically acting chlorpyrifos.

  • Content Type Journal Article
  • Pages 1-12
  • DOI 10.1007/s10646-012-0897-0
  • Authors
    • A. J. Baylay, Department of Biochemistry, University of Cambridge, The Sanger Building, 80 Tennis Court Road, Cambridge, CB2 1GA UK
    • D. J. Spurgeon, Centre for Ecology and Hydrology, MacLean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxon OX10 8BB, UK
    • C. Svendsen, Centre for Ecology and Hydrology, MacLean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxon OX10 8BB, UK
    • J. L. Griffin, Department of Biochemistry, University of Cambridge, The Sanger Building, 80 Tennis Court Road, Cambridge, CB2 1GA UK
    • Suresh C. Swain, School of Biomedical Sciences, Analytical and Environmental Sciences Division, King’s College London, 150 Stamford Street, London, SE1 9NH UK
    • Stephen R. Sturzenbaum, School of Biomedical Sciences, Analytical and Environmental Sciences Division, King’s College London, 150 Stamford Street, London, SE1 9NH UK
    • O. A. H. Jones, School of Applied Sciences, RMIT University, GPO Box 2476V, Melbourne, VIC 3001, Australia

Quelle: Ecotoxicology (Browse Results) | 5 Apr 2012 | 8:36 am CEST

Cytotoxicity and genotoxicity of chlorhexidine on macrophages in vitro

Abstract

Chlorhexidine (CHX) is the most widely used antiseptic for wound, skin disinfection, and dental hygiene. The aim of this study is to investigate the possible correlation between CHX-induced cytogenotoxicity and alterations in normal cell cycle on RAW264.7 macrophages. The cytotoxicity, mechanism of cell death, mitotic activity, and reactive oxygen species (ROS) generation were determined by tetrazolium bromide reduction assay, flow cytometry, cytokinesis-block proliferation index, and superoxide dismutase-inhibitable reduction of ferricytochrome c, respectively. The genotoxicity was measured using comet assay and cytokinesis-block micronucleus assay. The cytotoxicity of CHX in RAW264.7 cells presented a dose- and time-dependent manner (p < 0.05). The mode of cell death shifted from apoptosis to necrosis when the dosage of CHX increased. The genotoxicity of CHX in RAW264.7 cells had shown DNA damage in a dose-dependent manner (p < 0.05). Prolongation of cell cycle and the increase of ROS generation also expressed in a dose-dependent manner (p < 0.05). Taken together, the data suggested that CHX-induced cytotoxicity and genotoxicity on macrophages may be via ROS generation. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 4 Apr 2012 | 2:16 pm CEST

Inhibition of polyisoprenylated methylated protein methyl esterase by synthetic musks induces cell degeneration

Abstract

Synthetic fragrances are persistent environmental pollutants that tend to bioaccumulate in animal tissues. They are widely used in personal care products and cleaning agents. Worldwide production of Galaxolide and Tonalide are in excess of 4500 tons annually. Because of their widespread production and use, they have been detected in surface waters and fish in the US and Europe. Consumption of contaminated water and fish from such sources leads to bioaccumulation and eventual toxicity. Since fragrances and flavors bear structural similarities to polyisoprenes, it was of interest to determine whether toxicity by Galaxolide and Tonalide may be linked with polyisoprenylated methylated protein methyl esterase (PMPMEase) inhibition. A concentration-dependent study of PMPMEase inhibition by Galaxolide and Tonalide as well as their effects on the degeneration of cultured cells were conducted. Galaxolide and Tonalide inhibited purified porcine liver PMPMEase with Ki values of 11 and 14 μM, respectively. Galaxolide and Tonalide also induced human cancer cell degeneration with EC50 values of 26 and 98 μM (neuroblastoma SH-SY5Y cells) and 58 and 14 μM (lung cancer A549 cells), respectively. The effects on cell viability correlate well with the inhibition of PMPMEase activity in the cultured cells. Molecular docking analysis revealed that the binding interactions are most likely between the fragrance molecules and hydrophobic amino acids in the active site of the enzyme. These results appear to suggest that the reported neurotoxicity of these compounds may be associated with their inhibition of PMPMEase. Exposure to fragrances may pose a significant risk to individuals predisposed to developing degenerative disorders. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 4 Apr 2012 | 2:16 pm CEST

Toxicity thresholds for juvenile freshwater mussels Echyridella menziesii and crayfish Paranephrops planifrons, after acute or chronic exposure to Microcystis sp.

Abstract

Survival of juvenile freshwater mussels (Echyridella menziesii (Gray, 1843) formerly known as Hyridella menziesi) and crayfish (Paranephrops planifrons, White, 1842) decreased after four days exposure to microcystin-containing cell-free extracts (MCFE) of Microcystis sp. at concentrations typical of severe cyanobacterial blooms. Crayfish survival was 100, 80, and 50% in microcystin concentrations of 1339, 2426, and 11146 μg L−1 respectively, and shade- and shelter-seeking behavior was negatively affected when concentrations were ≥2426 μg L−1. Mussel survival decreased to 92% and reburial rates decreased to 16% after exposure for 96 h to MCFE containing microcystins at concentrations of 5300 μg L−1. Crayfish survival was 100% when fed freeze-dried Microcystis sp. incorporated into an artificial diet (6–100 μg microcystin kg−1 ww) at dietary doses from 0.03 to 0.55 μg g−1 body weight d−1 for 27 days. Specific growth rate was significantly lower in crayfish fed ≥0.15 μg g−1 body weight day−1 compared with controls, but not compared with a diet incorporating nontoxic cyanobacteria. Microcystins accumulated preferentially in crayfish hepatopancreas and mussel digesta as MCFE or dietary concentrations increased. These laboratory data indicate that, assuming dissolved oxygen concentrations remain adequate, and no simultaneous exposure to live Microcystis sp. cells, cell-free microcystins will only be a significant stressor to juvenile crayfish and mussels in severe Microcystis sp. blooms. In contrast, crayfish were negatively affected by relatively low concentrations of microcystins in artificial diets compared with those measured locally in benthic cyanobacterial mats. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 4 Apr 2012 | 2:16 pm CEST

Extensive Ace2 duplication and multiple mutations on Ace1 and Ace2 are related with high level of organophosphates resistance in Aphis gossypii

Abstract

Aphis gossypii (Glover) has been found to possess multiple mutations in the acetylcholinesterase (AChE) gene (Ace) that might involve target site insensitivity. In vitro functional expression of AChEs reveals that the resistant Ace1 (Ace1R) and Ace2 (Ace2R) were significantly less inhibited by eserine, omethoate, and malaoxon than the susceptible Ace1 (Ace1S) and Ace2 (Ace2S). Furthermore, in both the mutant and susceptible AChEs, Ace2 was significantly less sensitive to eserine, omethoate, and malaoxon than Ace1. These results suggested that both the mutant Ace1 and Ace2 were responsible for omethoate resistance, while the mutant Ace2 played a major role in insecticide resistance. The DNA copy number and transcription level of Ace2 were 1.52- and 1.88-fold higher in the ORR strain than in the OSS strain. Furthermore, the DNA copy number and transcription level of Ace2 were significantly higher than that of Ace1 in either OSS or ORR strains, demonstrating the involvement of Ace2 gene duplication in resistance. Thus, the authors conclude that omethoate resistance in cotton aphids appears to have evolved through a combination of multiple mutations and extensive Ace2R gene duplication. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 4 Apr 2012 | 2:15 pm CEST

Prenatal di-n-butyl phthalate exposure alters reproductive functions at adulthood in male rats

Abstract

This study was aimed to investigate the reproductive health in adult male rats exposed to di-n-butyl phthalate (DBP) during embryonic development. Pregnant rats were injected with DBP and F1 male rats were weaned and on postnatal day 100, used for mating with normal cycling females to assess reproductive performance. After completion of cohabitation period, rats were analyzed for other reproductive end points. Transplacental exposure to DBP significantly decreased fertility in adult male rats. Prenatal exposure to DBP significantly decreased sperm density, number of motile sperms, viable sperms, and hypoosmotic swelling tail coiled sperms with an increase in morphological abnormalities in sperms. Testicular steroidogenic enzyme activity levels and serum testosterone levels were significantly decreased in rats exposed to DBP during embryonic development. In conclusion, transplacental exposure to DBP impairs male reproductive performance by decreasing steroidogenesis and spermatogenesis. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 4 Apr 2012 | 2:15 pm CEST

Polybrominated diphenyl ethers disrupt molting in neonatal Daphnia magna

Abstract  
Polybrominated diphenyl ethers (PBDEs) are flame-retardants which can bioaccumulate and biomagnify and are found worldwide despite their banned usage in some countries. In recent years, the possibility that PBDEs may disrupt endocrine functions in vertebrates has been well investigated, but little attention has been paid to the endocrine disrupting potential in aquatic invertebrates. The current study aimed to investigate whether PBDEs affect molting in neonatal Daphnia magna. Prior to molting studies, 48 h LC50 values were tested for several environmentally prevalent PBDEs: PBDEs-28, -47, -99, -100 and -209. The 48 h LC50s determined were 110.7, 7.9, 2.6, and 11.1 Î¼g/L for PBDEs-28, -47, -99, and -100, respectively, but the highest concentration of PBDEs-209 tested (2.5 mg/L) did not affect survival at 48 h. Sublethal concentrations of these were used to investigate their potential effects on molting, assessed by the time taken to reach 4 molts. Molting studies found that PBDE-28 at 12 Î¼g/L significantly increased the time it took to complete 4 molts. PBDE-47 at 20 Î¼g/L inhibited daphnid molting initially but such an inhibitory effect disappeared with the prolongation of exposure due to the death of sensitive individuals. No other PBDEs affected molting at the concentrations tested, while still maintaining relatively high survival rates. In conclusion, this study found that PBDEs-28 and -47 can delay molting at μg/L concentrations, which raises concern for disrupted molting in crustaceans exposed to PBDEs.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0891-6
  • Authors
    • Rebecca Davies, Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
    • Enmin Zou, Department of Biological Sciences, Nicholls State University, Thibodaux, LA 70310, USA

Quelle: Ecotoxicology (Browse Results) | 2 Apr 2012 | 6:03 pm CEST

Erratum to: Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment

Erratum to: Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment

  • Content Type Journal Article
  • Category Erratum
  • Pages 1-1
  • DOI 10.1007/s10646-012-0890-7
  • Authors
    • Tjeerd Blacquière, Plant Research International, Wageningen University & Research, PO Box 69, 6700 AB Wageningen, The Netherlands
    • Guy Smagghe, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
    • Cornelis A. M. van Gestel, Department of Animal Ecology, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
    • Veerle Mommaerts, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium

Quelle: Ecotoxicology (Browse Results) | 2 Apr 2012 | 6:03 pm CEST

Oxidation of retinoic acids in hepatic microsomes of wild bullfrogs Lithobates catesbeianus environmentally-exposed to a gradient of agricultural contamination

Abstract  
Agricultural contaminants are suspected of contributing to the increased incidence of deformities and the decline of amphibians populations worldwide. Many authors have further suggested that a retinoid effect could be implicated in teratogenic mechanisms since the reported deformities resemble those caused by abnormal levels of retinoic acid (RA). We previously reported altered retinoid concentrations in male bullfrogs from the Yamaska River basin (Québec, Canada) associated with moderate-to-high agricultural activity, and the findings were consistent with a possible effect on hepatic RA oxidation. An in vitro assay was therefore optimized and hepatic microsomal RA oxidation in bullfrogs was found to be quite different from that of other vertebrates. With either all-transRA (atRA) or 13cisRA as the substrate, the major metabolite generated was at4-oxo-RA. The reaction with 13cisRA as substrate, markedly greater compared with atRA, was enhanced in the presence of a reducing agent and inhibited by cytochrome P450 inhibitors in a dose-dependent manner. Hepatic RA oxidation in male bullfrogs showed significant differences between sites with no clear relationship to a gradient of agricultural activity or 13cis-4-oxo-RA quantified in plasma. In contrast, the in vitro RA oxidation in females increased with the levels of contamination and coincided in vivo with higher plasma 13cis-4-oxo-RA concentration. The levels of circulating 4-oxo-derivatives could be influenced by hepatic RA oxidative metabolism as well as isomerization conditions or RA precursor levels.

  • Content Type Journal Article
  • Pages 1-13
  • DOI 10.1007/s10646-012-0889-0
  • Authors
    • Janik Thibodeau, Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, QC H3C 3P8, Canada
    • Sébastien Filion, Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, QC H3C 3P8, Canada
    • Philip Spear, Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, QC H3C 3P8, Canada
    • Joanne Paquin, Département de Chimie, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, QC H3C 3P8, Canada
    • Monique Boily, Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, QC H3C 3P8, Canada

Quelle: Ecotoxicology (Browse Results) | 31 Mar 2012 | 5:51 pm CEST

Acanthocephalan parasites: help or burden in gammarid amphipods exposed to cadmium?

Abstract  
We investigated the influence of the acanthocephalan parasite Polymorphus minutus on the mortality of its intermediate host, Gammarus roeseli, exposed to cadmium, by the measure of LC50–96h values as well as the bioaccumulation of cadmium both in the host and in its parasite. LC50 results revealed that infected G. roeseli males died less under cadmium stress than uninfected ones; while the converse has been observed in females. Cadmium resistance of infected males could be explained by a weaker bioconcentration factor (BCF) than in females. The lower BCF in infected individuals was closely related with an uptake of cadmium by P. minutus in its host. Nevertheless, although infected females had both weaker BCF and cadmium concentration in their body, the presence of P. minutus did not induce lower mortality than uninfected females. On the contrary, their sensitivity to cadmium was increased by the presence of P. minutus. We discuss the hypothesis that differences of mortality between uninfected and infected gammarids could be explained by a difference of cadmium bioconcentration in host, and by the cadmium bioaccumulation in the parasite. Indeed, results suggested that P. minutus could help G. roeseli to face with stress, what contributed to keep the host alive and favour the parasite transmission.

  • Content Type Journal Article
  • Pages 1188-1193
  • DOI 10.1007/s10646-012-0873-8
  • Authors
    • E. Gismondi, Laboratoire des Interactions Ecotoxicologie Biodiversité Ecosystèmes (LIEBE) Laboratory, CNRS UMR 7146, Université de Lorraine (UdL), Campus Bridoux, Avenue du Général Delestraint, 57070 Metz, France
    • C. Cossu-Leguille, Laboratoire des Interactions Ecotoxicologie Biodiversité Ecosystèmes (LIEBE) Laboratory, CNRS UMR 7146, Université de Lorraine (UdL), Campus Bridoux, Avenue du Général Delestraint, 57070 Metz, France
    • J.-N. Beisel, Laboratoire des Interactions Ecotoxicologie Biodiversité Ecosystèmes (LIEBE) Laboratory, CNRS UMR 7146, Université de Lorraine (UdL), Campus Bridoux, Avenue du Général Delestraint, 57070 Metz, France

Quelle: Ecotoxicology (Browse Results) | 30 Mar 2012 | 7:49 am CEST

Coelomic fluid: a complimentary biological medium to assess sub-lethal endosulfan exposure using 1H NMR-based earthworm metabolomics

Abstract  
Endosulfan is an environmentally persistent pesticide and has been shown to be genotoxic, neurotoxic and carcinogenic to surrounding organisms. Earthworms are widely used in environmental metabolomic studies to assess soil ecotoxicity. Previous nuclear magnetic resonance (NMR)-based metabolomic studies have analyzed earthworm tissue extracts after exposure to endosulfan and identified some key metabolic indicators that can be used as biomarkers of stress. However, some metabolites may have been masked due to overlap with other metabolites in the tissue extract. Therefore, in this study, the coelomic fluid (CF) and the tissue extract of the earthworm, Eisenia fetida, were both investigated using 1H NMR-based metabolomics to analyze their metabolic profile in response to endosulfan exposure at three sub-lethal (below LC50) concentrations. Principal component analysis determined the earthworm CF and earthworm tissue extract to both have significant separation between the exposed and control at the two highest sub-lethal endosulfan exposures (1.0 and 2.0 Î¼g cm−2). Alanine, glycine, malate, α-ketoglutarate, succinate, betaine, myo-inositol, lactate and spermidine in the earthworm CF and alanine, glutamine, fumarate, glutamate, maltose, melibiose, ATP and lactate in earthworm tissue extract were all detected as having significant fluctuations after endosulfan exposure. An increase in ATP production was detected by the increase activity in the citric acid cycle and by anaerobic metabolism. A significant decrease in the polyamine, spermidine after endosulfan exposure describes an apoptotic mode of protection which correlates to a previous endosulfan exposure study where DNA damage has been reported. This study highlights that earthworm CF is a complementary biological medium to tissue extracts and can be helpful to better understand the toxic mode of action of contaminants at sub-lethal levels in the environment.

  • Content Type Journal Article
  • Pages 1-13
  • DOI 10.1007/s10646-012-0884-5
  • Authors
    • Jimmy Yuk, Department of Chemistry, Scarborough College, University of Toronto, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
    • Myrna J. Simpson, Department of Chemistry, Scarborough College, University of Toronto, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
    • André J. Simpson, Department of Chemistry, Scarborough College, University of Toronto, 1265 Military Trail, Toronto, ON M1C 1A4, Canada

Quelle: Ecotoxicology (Browse Results) | 26 Mar 2012 | 6:10 pm CEST

Lethal effect of imidacloprid on the coccinellid predator Serangium japonicum and sublethal effects on predator voracity and on functional response to the whitefly Bemisia tabaci

Abstract  
Neonicotinoid insecticides are widely used for controlling sucking pests, and sublethal effects can be expected in beneficial arthropods like natural enemies. Serangium japonicum is an important predator in many agricultural systems in China, and a potential biological control agent against Bemisia tabaci. We evaluated the toxicity of imidacloprid to S. japonicum and its impact on the functional response to B. tabaci eggs. S. japonicum adults exposed through contact to dried residues of imidacloprid at the recommended field rate on cotton against B. tabaci (4 g active ingredient per 100 l, i.e. 40 ppm [part per million]), and reduced rates (25, 20, 15 and 10 ppm) for 24 h showed high mortality rates. The mortality induced by a lowest rate, 5 ppm, was not significantly different than the control group and thus it was considered as a sublethal rate. The lethal rate 50 and hazard quotient (HQ) were estimated to be 11.54 ppm and 3.47 respectively, indicating a risk for S. japonicum in treated fields (HQ > 2). When exposed to dried residues of imidacloprid at the sublethal rate (5 ppm) on cotton leaves, functional response of S. japonicum to B. tabaci eggs was affected with an increase in handling time and a reduction in peak consumption of eggs. Imidacloprid residues also disturbed predator voracity, the number of B. tabaci eggs consumed on treated leaves being significantly lower than on untreated leaves. All effects disappeared within a few hours after transfer to untreated cotton leaves. Imidacloprid systemically applied at the recommended field rate (for cotton) showed no toxicity to S. japonicum, nor affected the functional response of the predator. Sublethal effects of imidacloprid on S. japonicum observed in our study likely negatively affect S. japonicum development and reproductive capacity and may ultimately reduce predator population growth. These results hint at the importance of assessing potential effects of imidacloprid on S. japonicum for developing effective integrated pest management programs of B. tabaci in China.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0883-6
  • Authors
    • Yuxian He, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, 350013 People’s Republic of China
    • Jianwei Zhao, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, 350013 People’s Republic of China
    • Yu Zheng, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, 350013 People’s Republic of China
    • Nicolas Desneux, French National Institute for Agricultural Research (INRA), 400 Route des Chappes, 06903 Sophia Antipolis, France
    • Kongming Wu, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China

Quelle: Ecotoxicology (Browse Results) | 23 Mar 2012 | 6:49 pm CET

Rodenticide exposure in wood mouse and house mouse populations on farms and potential secondary risk to predators

Abstract  
We compared capture rates and exposure to SGARs of wood mice (Apodemus sylvaticus) and house mice (Mus domesticus) in autumn/winter on farms that currently used, had previously used, and never used SGARs. 6–10 weeks after baiting programmes began, 15 % of 55 wood mice and 33 % of 12 house mice had detectable liver SGAR residues. Wood mice with residues occurred on farms not using rodenticides, reflecting the high mobility of these animals, and four had multiple liver residues, possibly due to cross-contamination of baits. The winter decline in wood mouse numbers was similar on farms that did and did not use SGARs, suggesting little long-term impact of SGARs on populations on farms. Our results indicate residual levels of rodenticides will be ever present in small mammal prey across the agricultural landscape unless all farms in a locality cease application. The implications for secondary exposure and poisoning of predators are discussed.

  • Content Type Journal Article
  • Pages 1-8
  • DOI 10.1007/s10646-012-0886-3
  • Authors
    • David G. Tosh, School of Biological Sciences, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7BL Northern Ireland, UK
    • Robbie A. McDonald, Environment and Sustainability Institute, The University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, UK
    • Stuart Bearhop, Centre for Ecology and Conservation, The University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, UK
    • Neville R. Llewellyn, Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP UK
    • W. Ian Montgomery, School of Biological Sciences, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7BL Northern Ireland, UK
    • Richard F. Shore, Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP UK

Quelle: Ecotoxicology (Browse Results) | 23 Mar 2012 | 6:49 pm CET

Unraveling the concentration-dependent metabolic response of Pseudomonas sp. HF-1 to nicotine stress by 1H NMR-based metabolomics

Abstract  
Nicotine can cause oxidative damage to organisms; however, some bacteria, for example Pseudomonas sp. HF-1, are resistant to such oxidative stress. In the present study, we analyzed the concentration-dependent metabolic response of Pseudomonas sp. HF-1 to nicotine stress using 1H NMR spectroscopy coupled with multivariate data analysis. We found that the dominant metabolites in Pseudomonas sp. HF-1 were eight aliphatic organic acids, six amino acids, three sugars and 11 nucleotides. After 18 h of cultivation, 1 g/L nicotine caused significant elevation of sugar (glucose, trehalose and maltose), succinate and nucleic acid metabolites (cytidine, 5′-CMP, guanine 2′,3′-cyclic phosphate and adenosine 2′,3′-cyclic phosphate), but decrease of glutamate, putrescine, pyrimidine, 2-propanol, diethyl ether and acetamide levels. Similar metabolomic changes were induced by 2 g/L nicotine, except that no significant change in trehalose, 5′-UMP levels and diethyl ether were found. However, 3 g/L nicotine led to a significant elevation in the two sugars (trehalose and maltose) levels and decrease in the levels of glutamate, putrescine, pyrimidine and 2-propanol. Our findings indicated that nicotine resulted in the enhanced nucleotide biosynthesis, decreased glucose catabolism, elevated succinate accumulation, severe disturbance in osmoregulation and complex antioxidant strategy. And a further increase of nicotine level was a critical threshold value that triggered the change of metabolic flow in Pseudomonas sp. HF-1. These findings revealed the comprehensive insights into the metabolic response of nicotine-degrading bacteria to nicotine-induced oxidative toxicity.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0885-4
  • Authors
    • Yangfang Ye, School of Marine Science, Ningbo University, 818 Fenghua Road, Ningbo, 315211 China
    • Xin Wang, College of Life Science, Zhejiang University, 388 Yuhangtang Road, Hangzhou, 310058 China
    • Limin Zhang, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, West No. 30 Xiaohongsan, Wuhan, 430071 China
    • Zhenmei Lu, College of Life Science, Zhejiang University, 388 Yuhangtang Road, Hangzhou, 310058 China
    • Xiaojun Yan, School of Marine Science, Ningbo University, 818 Fenghua Road, Ningbo, 315211 China

Quelle: Ecotoxicology (Browse Results) | 22 Mar 2012 | 12:24 pm CET

Acute and chronic effects of atrazine and sodium dodecyl sulfate on the tropical freshwater cladoceran Pseudosida ramosa

Abstract  
Toxicities of atrazine and sodium dodecyl sulfate (SDS) to the tropical freshwater cladoceran Pseudosida ramosa were studied in the laboratory. Acute tests showed that the 48-h LC50 of atrazine was 20.9 mg l−1, while that of SDS was 11.1 mg l−1. P. ramosa showed to be slightly more sensitive than the other species of temperate cladocerans, in the assay conditions specified for each one. Long-term exposure of P. ramosa individuals to atrazine decreased the 21-day fecundity, the 21-day fertility and r m, at concentrations ranging from 0.8 to 3.2 mg l−1. Furthermore, fecundity and fertility at each brood decreased from the first to the fifth, at concentrations ranging from 0.8 to 3.2 mg l−1 and for the first three broods at the concentration of 0.4 mg l−1. Long-term exposure of female P. ramosa to SDS decreased the 21-day fecundity, the 21-day fertility and r m, at concentrations of 2 and 4 mg l−1. Fecundity and fertility of each brood were reduced from the first to the fifth, at concentrations of 2–4 mg l−1, and for the first three at concentrations of 0.5 and 1 mg l−1. The survival and moulting of the adult females were not affected by either chemical at the concentrations tested. Many water quality criteria in tropical regions are based on ecotoxicological tests with non-native species and this may lead to errors in setting the maximum permissible levels of chemicals in water bodies. Therefore, we reiterate here the idea of using native species in ecotoxicological assessments.

  • Content Type Journal Article
  • Pages 1-11
  • DOI 10.1007/s10646-012-0888-1
  • Authors
    • Emanuela Cristina Freitas, Post-Graduate Program of Ecology and Natural Resources, Department of Ecology and Evolutionary Biology, Federal University of São Carlos, Rodovia Washington Luis, km 235, São Carlos, SP CEP 13565-905, Brazil
    • Odete Rocha, Department of Ecology and Evolutionary Biology, Federal University of São Carlos, Rodovia Washington Luis, km 235, São Carlos, SP CEP 13565-905, Brazil

Quelle: Ecotoxicology (Browse Results) | 20 Mar 2012 | 5:52 pm CET

Synergistic interactions between PBDEs and PCBs in human neuroblastoma cells

Abstract

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants. Exposure to these chemicals has been associated with developmental neurotoxicity, endocrine dysfunction, and reproductive disorders. Humans and wildlife are generally exposed to a mixture of these environmental pollutants, highlighting the need to evaluate the potential effects of combined exposures. In this study, we investigated the cytotoxic effects of the combined exposure to two PBDEs and two PCBs in a human neuronal cell line. 2,2′,4,4′-Tetrabromodiphenyl ether, 2,2′,4,4′,5-pentabromodiphenyl ether, PCB-126 (3,3′,4,4′,5-pentachlorobiphenyl; a dioxin-like PCB), and PCB-153 (2,2′,4,4′,5,5′-hexachlorobiphenyl; a non-dioxin-like PCB) were chosen, because their concentrations are among the highest in human tissues and the environment. The results suggest that the nature of interactions is related to the PCB structure. Mixtures of PCB-153 and both PBDEs had a prevalently synergistic effect. In contrast, mixtures of each PBDE congener with PCB-126 showed additive effects at threshold concentrations, and synergistic effects at higher concentrations. These results emphasize the concept that the toxicity of xenobiotics may be affected by possible interactions, which may be of significance given the common coexposures to multiple contaminants. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 20 Mar 2012 | 11:57 am CET

The roles of endoplasmic reticulum stress and mitochondrial apoptotic signaling pathway in quercetin-mediated cell death of human prostate cancer PC-3 cells

Abstract

Prostate cancer has its highest incidence and is becoming a major concern. Many studies have shown that traditional Chinese medicine exhibited antitumor responses. Quercetin, a natural polyphenolic compound, has been shown to induce apoptosis in many human cancer cell lines. Although numerous evidences show multiple possible signaling pathways of quercetin in apoptosis, there is no report to address the role of endoplasmic reticulum (ER) stress in quercetin-induced apoptosis in PC-3 cells. The purpose of this study was to investigate the effects of quercetin on the induction of the apoptotic pathway in human prostate cancer PC-3 cells. Cells were treated with quercetin for 24 and 48 h and at various doses (50–200 μM), and cell morphology and viability decreased significantly in dose-dependent manners. Flow cytometric assay indicated that quercetin at 150 μM caused G0/G1 phase arrest (31.4–49.7%) and sub-G1 phase cells (19.77%) for 36 h treatment and this effect is a time-dependent manner. Western blotting analysis indicated that quercetin induces the G0/G1 phase arrest via decreasing the levels of CDK2, cyclins E, and D proteins. Quercetin also stimulated the protein expression of ATF, GRP78, and GADD153 which is a hall marker of ER stress. Furthermore, PC-3 cells after incubation with quercetin for 48 h showed an apoptotic cell death and DNA damage which are confirmed by DAPI and Comet assays, leading to decrease the antiapoptotic Bcl-2 protein and level of ΔΨm, and increase the proapoptotic Bax protein and the activations of caspase-3, -8, and -9. Moreover, quercetin promoted the trafficking of AIF protein released from mitochondria to nuclei. These data suggest that quercetin may induce apoptosis by direct activation of caspase cascade through mitochondrial pathway and ER stress in PC-3 cells. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 20 Mar 2012 | 11:56 am CET

Monitoring toxigenic Microcystis strains in the Missisquoi bay, Quebec, by PCR targeting multiple toxic gene loci

Abstract

The increasing incidence of mixed assemblages of toxic and nontoxic cyanobacterial blooms in Quebec's freshwater bodies over the last decade, coupled with inherent inadequacies of current monitoring approaches, warrants development of sensitive and reliable tools for assessing the toxigenic potential of these water blooms. In this study, we applied three independent polymerase chain reaction (PCR) assays that simultaneously target the microcystin synthetase (mcy) genes A, E, and G to rapidly and reliably detect and quantify potentially toxic Microcystis genotypes in the Missisquoi bay, Quebec, Canada. Linear regressions of quantitative PCR threshold cycles (Ct) against the logarithm of their respective Microcystis cell number equivalents resulted in highly significant linear curves with coefficients of determination (R2) greater than 0.99 (p < 0.0001, n = 6) and reaction efficiencies of 91.0, 95.8, and 92.7%, respectively, for the mcyA, mcyE, and mcyG-based quantitative real-time PCR (qPCR) assays. The three assays successfully estimated potential microcystin-producing Microcystis genotypes from all field samples. The proportions of MicrocystismcyA, mcyE, and mcyG genotypes to total Microcystis cell counts showed substantial spatial variability ranging between 1.7–21.6%, 1.9–11.2%, and 2.2–22.6%, respectively. Correlation of microscopically determined total Microcystis counts to qPCR-based MicrocystismcyA, mcyE, or mcyG cell number equivalents resulted in highly significant associations with R2 > 0.90. Thus, PCR-based assays targeting the mcyA, mcyG, and/or mcyE genes can serve as powerful screening tools for rapid and sensitive estimation of microcystin-producing Microcystis genotypes in freshwater water bodies. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 20 Mar 2012 | 11:56 am CET

Effects of 4-nonylphenol on balance of steroid and thyroid hormones in sexually immature male yellowfin seabream (Acanthopagrus latus)

Abstract

Nonylphenol (NP) is an endocrine disrupting chemical which has been shown to be able to modulate the endocrine system of various organisms by different mechanisms. The objective of this study was to investigate the potential effects of 4-NP on steroid and thyroid hormone levels in sexually immature male yellowfin seabream (Acanthopagrus latus), a protandrous hermaphrodite species. For this, the fish were injected with ascending doses (10, 50, 100, and 200 μg g−1 body weight) of 4-nonylphenol (4-NP) or vehicle during 2 weeks. After 7 and 14 days the fish were anesthetized, blood sample were collected and plasma steroid and thyroid hormone concentrations were quantified by radioimmunoassay. The result showed that 4-NP induced a significant increase in 17β-etradiol levels at dose 10 μg g−1, while the levels of this hormone in the higher doses decreased compared with the control group. However, 4-NP treatment did not have any significant effect on plasma levels of testosterone. In addition, it was observed that 4-NP affect the level of thyroid hormones in fish. Plasma thyroxine levels increased in a dose-dependent manner after 7 and 14 days of the exposure. In contrast, a significant decrease in triiodothyronine levels was observed during the experiment period. Moreover, no significant change was detected for thyroid stimulating hormone levels in 4-NP-treated fish. These results indicated that 4-NP could lead to disturb the balance of steroid and thyroid hormones with potential consequences for sexually immature male yellowfin seabream. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 20 Mar 2012 | 11:56 am CET

The surface reactivity and implied toxicity of ash produced from sugarcane burning

Abstract

Sugarcane combustion generates fine-grained particulate that has the potential to be a respiratory health hazard because of its grain size and composition. In particular, conversion of amorphous silica to crystalline forms during burning may provide a source of toxic particles. In this study, we investigate and evaluate the toxicity of sugarcane ash and bagasse ash formed from commercial sugarcane burning. Experiments to determine the main physicochemical properties of the particles, known to modulate biological responses, were combined with cellular toxicity assays to gain insight into the potential reactions that could occur at the particle-lung interface following inhalation. The specific surface area of the particles ranged from ∼16 to 90 m2 g−1. The samples did not generate hydroxyl- or carbon-centered radicals in cell-free tests. However, all samples were able to ‘scavenge’ an external source of hydroxyl radicals, which may be indicative of defects on the particle surfaces that may interfere with cellular processes. The bioavailable iron on the particle surfaces was low (2–3 μmol m−2), indicating a low propensity for iron-catalyzed radical generation. The sample surfaces were all hydrophilic and slightly acidic, which may be due to the presence of oxygenated (functional) groups. The ability to cause oxidative stress and membrane rupture in red blood cells (hemolysis) was found to be low, indicating that the samples are not toxic by the mechanisms tested. Cytotoxicity of sugarcane ash was observed, by measuring lactate dehydrogenase release, after incubation of relatively high concentrations of ash with murine alveolar macrophage cells. All samples induced nitrogen oxide release (although only at very high concentrations) and reactive oxygen species generation (although the bagasse samples were less potent than the sugarcane ash). However, the samples induced significantly lower cytotoxic effects and nitrogen oxide generation when compared with the positive control. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 20 Mar 2012 | 11:30 am CET

Biodegradation of bensulfuron-methyl and its effect on bacterial community in paddy soils

Abstract  
Bensulfuron-methyl (BSM) is a new kind of sulfonylurea herbicide widely used to control broad-leaf weeds in rice paddies. The aim of this work was to study BSM biodegradation in paddy soils with BSM-degrading bacteria Bacillus megaterium L1 and Brevibacterium sp. BH and its effect on the structures of soil bacterial community. More than 90 % of BSM could be degraded in paddy soils with 0.0355 mg kg−1 BSM concentration. Addition of BSM-degrading bacterial strains Bacillus megaterium L1 into BSM contaminated paddy soil could have the half-life time of BSM compared to treatment without Bacillus megaterium L1 inoculation. Denaturing gradient gel electrophoresis and principle component analysis indicated that the diversity of the soil microbial community structure changed along with the addition of BSM, which recovered at the end of the experiment (5 weeks). Addition of BSM-degrading bacteria Bacillus megaterium L1 enriched the diversity of soil microbial community structure in paddy soils. This study provides information on the biodegradation of BSM and BSM’s influences on the soil bacteria microbial community structures.

  • Content Type Journal Article
  • Pages 1-10
  • DOI 10.1007/s10646-012-0882-7
  • Authors
    • Xiao-Yan Lin, Rice Product Quality Inspection and Supervision Testing Center, China National Rice Research Institute, Hangzhou, 310006 People’s Republic of China
    • Yu-Yi Yang, School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan, 430073 People’s Republic of China
    • Yu-Hua Zhao, Institute of Microbiology, College of Life Sciences, Zhejiang University, Zijingang, Hangzhou, 310058 People’s Republic of China
    • Qing-Lin Fu, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021 People’s Republic of China

Quelle: Ecotoxicology (Browse Results) | 19 Mar 2012 | 6:12 pm CET

Protective role of zinc during aluminum-induced hepatotoxicity

Abstract

The study was carried out to assess the role of zinc (Zn) in mitigating the biochemical alterations induced by aluminum (Al) in rat liver. Rats were divided into four groups: normal control, Al treated (AlCl3, 100 mg/kg b.wt./day), Zn treated (ZnSO4, 227 mg/L drinking water), and combined Al + Zn treated. Al and zinc treatments were given for a total duration of 2 months. Al treatment caused a significant increase in the activity of alkaline phosphatase (ALP), but decreased aspartate aminotransferase (AST) and alanine aminotranferase (ALT) activities, which showed the reverse trend following Zn supplementation. Levels of lipid peroxidation (LPx) and activities of catalase and glutathione-S-transferase (GST) were significantly decreased following Al treatment, which, however, were increased significantly in Zn co-treated rats. Further Al exposure showed a significant increase in reduced glutathione (GSH) content as well as activities, of superoxide dismutase (SOD) and glutathione reductase (GR). However, Zn supplementation to Al-treated rats brought down the raised levels of reduced (GSH) and SOD to within normal limits, but caused no effect on GR activity. Furthermore, Al treatment also resulted in alterations in liver histoarchitecture with disruption of hepatic cords and increased vacuolization, which were close to normal following Zn supplementation. The present study reveals that Zn is effective in attenuating the liver damage inflicted by Al toxicity. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 16 Mar 2012 | 8:46 am CET

Effects of carbofuran and deltamethrin on acetylcholinesterase activity in brain and muscle of the common carp

Abstract

This work investigated the effect from exposure to insecticides carbofuran and deltamethrin on acetylcholinesterase (AChE) activity in the brain and muscle of common carp (Cyprinus carpio). Both pesticides were evaluated through two separate experiments, and carp were exposed in a semi-static system to three different concentrations of carbofuran (10, 50, and 100 μg/L) and deltamethrin (0.08, 0.4, and 0.8 μg/L) during a month with sampling times at 0, 4, 15, and 30 days (n = 7 from each aquarium). AChE activity was significantly inhibited in both organs of carps exposed to carbofuran at all sampling times depending on dose and time, reaching inhibition values of 73.5 and 67.1%, in brain and muscle tissues respectively, after 30 days with the highest concentration. On the contrary, AChE activity was not significantly affected after deltamethrin exposure at all concentrations and times of the assay. This study shows that the measurement of brain and muscle AChE activity in Cyprinus carpio is a useful biomarker of carbamates exposure and/or effects, but has no application with pyrethroids. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 16 Mar 2012 | 8:45 am CET

Tissue-specific copper accumulation, zinc levels, induction, and purification of metallothionein in freshwater crab Sinopotamon henanense exposed to subacute waterborne copper

Abstract

Copper (Cu) is one of the most important essential metals for crustaceans, buttoxic in excess. Metallothioneins (MT) are a family of low molecular weight, cysteine-rich, metal-binding proteins, which play important roles in metal homeostasis, detoxification, and cytoprotection. In the present study, Sinopotamon henanense were exposed to 0 (controls), 2.86, and 14.3 mg L−1 waterborne Cu, Cu accumulation, zinc (Zn) levels and MT induction in gills and hepatopancreas were determined with Cd/Hemoglobin saturation assay and atomic absorption spectrophotometry method. Results showed that Cu accumulation and MT levels were both tissue-specific and revealed some time-dependent and dose-dependent, respectively. The highest Cu accumulations of 82.10 ± 16.38 μg g−1 w wt were observed in the gill after 15 days of 14.3 mg L−1 Cu exposure, the peak MT induction of 136.16 ± 19.39 μg g−1 w wt were observed in the hepatopancreas after 3 day of 14.3 mg L−1 Cu exposure.In addition, the essential metal homeostasis of Zn was disturbed in some ways by subacute Cu exposure. The calculated ratios of actual Cu to theoretical maximum metal bound by MT indicating that the hepatopancreas had much greater Cu-binding potentials than the gills. Positive correlation were shown between MT induction and Cu accumulation both in hepatopancreas and gills, indicating that MT induction in S. henanense can be considered as a biomarker for subacute waterborne Cu pollution. Furthermore, the Cu induced MT (CuMT) from S. henanense was purified using acetone precipitation (50–80%), followed by gel filtration chromatography and anion exchange chromatography. SDS-PAGE and time-of-flight mass spectrometry analysis showed that S. henanense CuMT possess two isoforms and both mainly existed as monomer and dimmer forms. These present studies will be helpful to increase the database information of heavy metal-induced MT in terms of crustaceans. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 16 Mar 2012 | 8:04 am CET

Practical considerations for conducting ecotoxicity test methods with manufactured nanomaterials: what have we learnt so far?

Abstract  
This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test media during ecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensions during experiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench.

  • Content Type Journal Article
  • Pages 933-972
  • DOI 10.1007/s10646-012-0862-y
  • Authors
    • Richard D. Handy, Ecotoxicology Research and Innovation Centre, School of Biomedical & Biological Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA UK
    • Nico van den Brink, Alterra, Wageningen UR, Box 47, Wageningen, NL6700AA The Netherlands
    • Mark Chappell, U.S. Army Engineer Research & Development Center, Vicksburg, MS, USA
    • Martin Mühling, Institute of Biological Sciences, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
    • Renata Behra, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
    • Maria DuÅ¡inská, Health Effects Laboratory, CEE, NILU (Norwegian Institute for Air Research), P.O. Box 100, 2027 Kjeller, Norway
    • Peter Simpson, WCA Environment, Brunel House, Volunteer Way, Faringdon, SN7 7YR UK
    • Jukka Ahtiainen, Finnish Safety and Chemicals Agency, P.O. Box 66, 00521 Helsinki, Finland
    • Awadhesh N. Jha, Ecotoxicology Research and Innovation Centre, School of Biomedical & Biological Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA UK
    • Jennifer Seiter, U.S. Army Engineer Research & Development Center, Vicksburg, MS, USA
    • Anthony Bednar, U.S. Army Engineer Research & Development Center, Vicksburg, MS, USA
    • Alan Kennedy, U.S. Army Engineer Research & Development Center, Vicksburg, MS, USA
    • Teresa F. Fernandes, School of Life Sciences, Heriot-Watt University, Edinburgh, EH14 4AS Scotland, UK
    • Michael Riediker, Institute for Work and Health, IST, Bugnon 21, 1011 Lausanne, Switzerland

Quelle: Ecotoxicology (Browse Results) | 15 Mar 2012 | 6:14 pm CET

Sublethal effects of atrazine on embryo-larval development of Rhinella arenarum (Anura: Bufonidae)

Abstract  
Atrazine (ATR), one of the most widely used herbicides in the world, affects not only target organisms but also the biota in general. Here, the teratogenic and neurotoxic effects of ATR on Rhinella arenarum (South American toad) embryos, and larvae were evaluated by means of standardized bioassays during acute and chronic exposures. The herbicide had a significant incidence of malformations, with a Teratogenic Index (TI) of 3.28. The main effects were delayed development, reduced body size, microcephaly, axial flexures, wavy tail and edema. In addition, delayed development, reduced development of forelimbs, and edema were recorded at metamorphosis stages. Scanning electron microscopy allowed observing different degrees of cellular dissociation and persistent cilliar cells in specific regions like the adhesive structure and tail fin. Results obtained by ATR 24 h pulse exposures at six developmental stages pointed out blastula as the most susceptible developmental stage both for immediate and delayed adverse effects. A noteworthy recovery capacity from acute toxic effects was recorded from the neural plate stage onwards. Regarding neurotoxic effects, abnormal, and erratic swimming and spasmodic contractions were recorded. Both the teratogenic and neurotoxic effects reported in this study demonstrate the importance of evaluating sublethal effects in non-target organisms as they could imply reduced fitness of individuals and eventually a population decline. The Hazard Quotients (HQ) for ATR ranged from 0.14 to 10.80, and the fact that some of these values are above USEPA’s level of concern indicate that ATR is likely a risk to R. arenarum.

  • Content Type Journal Article
  • Pages 1251-1259
  • DOI 10.1007/s10646-012-0880-9
  • Authors
    • Gabriela V. Svartz, Instituto de Ciencias Ambientales y Salud. Fundación PROSAMA, 752 (1405) Paysandú, Buenos Aires, Argentina
    • Jorge Herkovits, Instituto de Ciencias Ambientales y Salud. Fundación PROSAMA, 752 (1405) Paysandú, Buenos Aires, Argentina
    • Cristina S. Pérez-Coll, Instituto de Investigación e Ingeniería Ambiental-3iA (UNSAM), Belgrano, 3563 (1650) San Martín, Buenos Aires, Argentina

Quelle: Ecotoxicology (Browse Results) | 14 Mar 2012 | 6:00 pm CET

Finding biomarkers is getting easier

Abstract  
Single biomarkers are rarely accurate. Even suites of biomarkers can give conflicting results. Ideally potent combinations of variables are isolated which accurately identify specific analytes and their level of toxicity. The search for such combinations can be done by reducing the thousands of candidate variables to the small number necessary for treatment classification. When the key variables are recognized by machine learning (ML) the results are quite surprising, given the apparent failure of other searching methods to produce good diagnostics. Proteins seem especially useful for portable field tests of a variety of adverse conditions. This review shows how ML, in particular artificial neural networks, can find potent biomarkers embedded in any type of expression data, mainly proteins in this article. A computer does multiple iterations to produce sets of proteins which systematically identify (to near 100% accuracy) the treatment classes of interest. Whether these proteins are useful in actual diagnoses is tested by presenting the computer model with unknown classes. Finding the biomarkers is getting easier but there still must be confirmation, by multivariable statistics and with field studies.

  • Content Type Journal Article
  • Category Review Article
  • Pages 631-636
  • DOI 10.1007/s10646-011-0848-1
  • Authors
    • Brian Patrick Bradley, Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA

Quelle: Ecotoxicology (Browse Results) | 12 Mar 2012 | 6:29 pm CET

An approach to detecting estrogenic endocrine disruption via choriogenin expression in an estuarine model fish species

Abstract  
A large body of work has established a link between endocrine disrupting compounds (EDCs) and a number of abnormalities in fishes. However, most EDC studies use several standard laboratory denizens to assess impacts, so assumptions about sensitivity are primarily based on these few species. Additionally, existing methods rely on obtaining sufficient plasma to measure EDC biomarkers. Our objectives were (a) to establish a new model species for estuarine fishes, (b) to evaluate endocrine impacts with a highly sensitive and specific biomarker, and (c) to develop a method for the analysis of this biomarker in small fish that do not possess sufficient blood plasma for protein measurement. As such, we created a polyclonal antibody (Ab) to the estrogen-responsive proteins chorion (Ch) and choriogenin (Chg) in Menidia beryllina, found throughout coastal North America and already utilized in EPA Whole Effluent Testing. We then validated the Ab by using it to measure the response to aqueous ethinylestradiol (EE2) through the development an ELISA using Menidia whole body homogenate (WBH). Sensitivity of the Ab to Menidia WBH is greater than that of the commercially available option. ELISA sensitivity, with a detection limit of 5 ng/ml and a working range of 22.6–1370.9 ng/ml, is comparable to ELISAs developed to measure plasma Chg. To our knowledge this is the first ELISA method developed for the detection of Chg using WBH. Including additional model species and methods allowing the evaluation of alternative sample matrices will contribute to an enhanced understanding of inter-species differences in EDC response.

  • Content Type Journal Article
  • Category Technical Note
  • Pages 1272-1280
  • DOI 10.1007/s10646-012-0879-2
  • Authors
    • Susanne M. Brander, Department of Environmental Toxicology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
    • Bryan J. Cole, Bodega Marine Laboratory, University of California, Davis, P.O. Box 247, Bodega Bay, CA 94923, USA
    • Gary N. Cherr, Departments of Environmental Toxicology and Nutrition, Bodega Marine Laboratory, University of California, Davis, P.O. Box 247, Bodega Bay, CA 94923, USA

Quelle: Ecotoxicology (Browse Results) | 12 Mar 2012 | 6:29 pm CET

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors

Abstract  
In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms’ ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms’ response to glyphosate, it had little influence on biofilms’ response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC50 = 11.7 mg L−1) than of high-light adapted communities (EC50 = 35.6 mg L−1). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

  • Content Type Journal Article
  • Pages 1208-1224
  • DOI 10.1007/s10646-012-0876-5
  • Authors
    • Chloé Bonnineau, Institute of Aquatic Ecology, Facultat de Ciències, Universitat de Girona, Avinguda Montilivi s/n, 17071 Girona, Spain
    • Irene Gallardo Sague, Institute of Aquatic Ecology, Facultat de Ciències, Universitat de Girona, Avinguda Montilivi s/n, 17071 Girona, Spain
    • Gemma Urrea, Institute of Aquatic Ecology, Facultat de Ciències, Universitat de Girona, Avinguda Montilivi s/n, 17071 Girona, Spain
    • Helena Guasch, Institute of Aquatic Ecology, Facultat de Ciències, Universitat de Girona, Avinguda Montilivi s/n, 17071 Girona, Spain

Quelle: Ecotoxicology (Browse Results) | 10 Mar 2012 | 5:44 pm CET

Perinatal exposure to low doses of tributyltin chloride advances puberty and affects patterns of estrous cyclicity in female mice

Abstract

Tributyltin (TBT), a proven endocrine-disrupting chemical, is well known to induce imposex in female gastropods. Herein we demonstrate the effects of low doses of tributyltin chloride (TBTCl) on the female offspring of KM mice. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. TBTCl dramatically advanced the age of onset of vaginal opening (VO) and first vaginal estrus, and reduced body weights at VO and first estrus. Furthermore, perinatal treatment with TBTCl significantly reduced the number of days between VO and first estrus. In addition, female offspring from dams exposed to 10 and 100 μg kg−1 TBTCl exhibited altered patterns of estrous cyclicity in adulthood. In conclusion, perinatal exposure to low doses TBTCl result in early puberty and impaired estrous cyclicity in female mice, which suggest that TBTCl might act as an estrogen agonist or/and a disruptor on hypothalamic–pituitary function in the present study. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 24 Feb 2012 | 8:10 am CET

Toxicity of pamam-coated gold nanoparticles in different unicellular models

Abstract

Polyamidoamine (PAMAM) dendrimers are used for many pharmaceutical and biomedical applications. However, the toxicological risks of several PAMAM-based compounds are still not fully evaluated, despite evidences of PAMAM deleterious effects on biological membranes, leading to toxicity. In this report, we investigated the toxicity of generation 0 PAMAM-coated gold nanoparticles (AuG0 NPs) in four different models to determine how different cellular systems are affected by PAMAM-coated NPs. Toxicity was evaluated in two mammalian cell lines, Neuro 2A and Vero, in the green alga Chlamydomonas reinhardtii and the bacteria Vibrio fischeri. AuG0 NP treatments reduced cell metabolic activity in algal and bacterial cells, measured by esterase enzymatic activity (C. reinhardtii) and luminescence emission (V. fischeri). EC50 value after 30 min of treatment was similar in both organisms, with 0.114 and 0.167 mg mL−1 for C. reinhardtii and V. fischeri, respectively. On the other hand, AuG0 NPs induced no change of mitochondrial activity in mammalian cells after 24 h of treatment to up to 0.4 mg mL−1 AuG0 NPs. Change in the absorption spectra of AuG0 NP in the mammalian cell culture media may indicate an alteration of NP properties that contributed to the low toxicity of AuG0 NPs in mammalian cells. For a safe development of PAMAM-based nanomaterials, the difference of sensitivity between mammalian and microbial cells, as well as the modulation of NPs toxicity by medium properties, should be taken into account when designing PAMAM NPs for applications that may lead to their introduction in the environment. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:42 pm CET

Cell death in relation to DNA damage after exposure to the jellyfish Pelagia noctiluca nematocysts

Abstract

Studies on the toxicity of Mediterranean jellyfish have gained attention owing to their weak toxic properties. Our research has been mainly performed on the Scyphomedusae. Pelagia noctiluca is a scyphozoan jellyfish which causes a danger to sea bathers and fishery damages in the Mediterranean Sea. To check whether the cytotoxicity of Pelagia noctiluca nematocysts was associated to DNA lesions, we have looked for DNA fragmentation by means of the Comet and chromosome aberration assays. To specify cell death pathway, we have investigated caspase-3 activation. Our results have shown that nematocysts reduced cell viability and induced DNA fragmentation in a concentration-dependent manner with a maximum effect at 150 000 nematocysts mL−1. The high percentage of chromosome aberrations also emphasized the genotoxic character of Pelagia noctiluca nematocysts in Vero cells. This fragmentation was correlated to apoptosis induction which was confirmed by caspase-3 activation. In conclusion, the present report has suggested that Pelagia noctiluca nematocysts were able to promote apoptosis in Vero cells and therefore may be useful in cancer therapy. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:40 pm CET

Scutellaria barbata inhibits angiogenesis through downregulation of HIF-1 α in lung tumor

Abstract

Hypoxia, a hallmark of many solid tumors, is associated with angiogenesis and tumor progression. Hypoxia-inducible factor-1 (HIF-1) plays a significant role in tumor angiogenesis. In this study, the authors constructed a selective platform to screen the traditional Chinese medicine as anti-angiogenic agent. The authors examined the molecular mechanism by which Scutellaria barbata regulates HIF-1-dependent expression of vascular endothelial growth factor (VEGF), which is an important angiogenic factor. Hypoxia promotes angiogenesis by increasing VEGF expression and secretion. Herein, the expression of VEGF was decreased by treatment with S. barbata in tumor cells. Meanwhile, S. barbata reduced the migration and proliferation of endothelial cells under hypoxic condition. S. barbata inhibited the expression of HIF-1α, as well as phosphorylated their upstream signal mediators AKT. S. barbata significantly inhibited the tumor growth in vivo and immunohistochemical studies in the tumors revealed decreased intratumoral microvessel density. These results suggest that the traditional Chinese medicine therapy using S. barbata, which exerts anti-angiogenic activities, represents a promising strategy for the treatment of tumors. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:39 pm CET

Water-insoluble fraction of airborne particulate matter (PM10) induces oxidative stress in human lung epithelial A549 cells

Abstract

Exposure to ambient airborne particulate matter (PM) with an aerodynamic diameter less than 10 μm (PM10) links with public health hazards and increases risk for lung cancer and other diseases. Recent studies have suggested that oxidative stress is a key mechanism underlying the toxic effects of exposure to PM10. Several components of water-soluble fraction of PM10 (sPM10) have been known to be capable of inducing oxidative stress in in vitro studies. In this study, we investigated if water-insoluble fraction of PM10 (iPM10) could be also capable of inducing oxidative stress and oxidative damage. Human lung epithelial A549 cells were exposed to 10 μg/mL of sPM10, iPM10 or total PM10 (tPM10) preparation for 24 h. Here, we observed that all three PM10 preparations reduced cell viability and induced apoptotic cell death in A549 cells. We further found that, similar to the exposure to sPM10 and tPM10, the intracellular level of hydrogen peroxide (H2O2) in the iPM10-exposed cells was increased significantly; meanwhile the activity of catalase was decreased significantly as compared with the unexposed control cells, resulting in significant DNA damage. Our data obtained from inductively coupled plasma-mass spectrometry (ICP-MS) assays showed that iron is the most abundant metal in all three PM10 preparations. Thus, we have demonstrated that, similar to sPM10, iPM10 is also capable of inducing oxidative stress by probably inducing generation of H2O2 and impairing enzymatic antioxidant defense, resulting in oxidative DNA damage and even apoptotic cell death through the iron-catalyzed Fenton reaction. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:38 pm CET

Effects of cadmium alone and in combination with low molecular weight chitosan on metallothionein, glutathione-S-transferase, acid phosphatase, and ATPase of freshwater crab Sinopotamon yangtsekiense

Abstract

Cadmium (Cd) is an environmental contaminant showing a variety of deleterious effects, including the potential threat for the ecological environment and human health via food chains. Low molecular weight chitosan (LMWC) has been demonstrated to be an effective antioxidant. Metallothionein (MT) mRNA levels and activities of glutathione-S-transferase (GST), superoxide dismutase (SOD), acid phosphatase (ACP), Na+,K+-ATPase, and Ca2+-ATPase as well as malondialdehyde (MDA) contents in the gills of the freshwater crab Sinopotamon yangtsekiense were analyzed in vivo in order to determine the injury of Cd exposure on the gill tissues as well as the protective effect of LMWC against this injury. The results showed that there was an apparent accumulation of Cd in the gills, which was lessened by the presence of LMWC. Moreover, Cd2+ significantly increased the gill MT mRNA levels, ACP activity and MDA content while decreasing the activities of SOD, GST, Na+,K+-ATPase, and Ca2+-ATPase in the crabs relative to the control. Cotreatment with LMWC reduced the levels of MT mRNA and ACP but raised the activities of GST, Na+,K+-ATPase, and Ca2+-ATPase in gill tissues compared with the crabs exposed to Cd2+ alone. These results suggest that LMWC may exert its protective effect through chelating Cd2+ to form LMWC-Cd2+ complex, elevating the antioxidative activities of GST, Na+,K+-ATPase, and Ca2+-ATPase as well as alleviating the stress pressure on MT and ACP, consequently protecting the cell from the adverse effects of Cd. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:32 pm CET

Evaluation of the cytotoxicity of organic dust components on THP1 monocytes-derived macrophages using high content analysis

Abstract

Organic dust contains pathogen-associated molecular patterns (PAMPs) which can induce significant airway diseases following chronic exposure. Mononuclear phagocytes are key protecting cells of the respiratory tract. Several studies have investigated the effects of PAMPs and mainly endotoxins, on cytokine production. However the sublethal cytotoxicity of organic dust components on macrophages has not been tested yet. The novel technology of high content analysis (HCA) is already used to assess subclinical drug-induced toxicity. It combines the capabilities of flow cytometry, intracellular fluorescence probes, and image analysis and enables rapid multiple analyses in large numbers of samples. In this study, HCA was used to investigate the cytotoxicity of the three major PAMPs contained in organic dust, i.e., endotoxin (LPS), peptidoglycan (PGN) and β-glucans (zymosan) on THP-1 monocyte-derived macrophages. LPS was used at concentrations of 0.005, 0.01, 0.02, 0.05, 0.1, and 1 μg/mL; PGN and zymosan were used at concentrations of 1, 5, 10, 50, 100, and 500 μg/mL. Cells were exposed to PAMPs for 24 h. In addition, the oxidative burst and the phagocytic capabilities of the cells were tested. An overlap between PGN intrinsic fluorescence and red/far-red fluorescent dyes occurred, rendering the evaluation of some parameters impossible for PGN. LPS induced sublethal cytotoxicity at the lowest dose (from 50 ng/mL). However, the greatest cytotoxic changes occurred with zymosan. In addition, zymosan, but not LPS, induced phagosome maturation and oxidative burst. Given the fact that β-glucans can be up to 100-fold more concentrated in organic dust than LPS, these results suggest that β-glucans could play a major role in macrophage impairment following heavy dust exposure and will merit further investigation in the near future. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:31 pm CET

Acute exposure to pure cylindrospermopsin results in oxidative stress and pathological alterations in tilapia (Oreochromis niloticus)

Abstract

Cylindrospermopsin (CYN) is increasingly recognized as a potential threat to drinking water safety, due to its ubiquity. This cyanotoxin has been found to cause toxic effects in mammals, and although fish could be in contact with this toxin, acute toxicity studies on fish are nonexistent. This is the first study showing that single doses of CYN pure standard (200 or 400 μg CYN/kg fish bw) by oral route (gavage) generate histopathological effects in fish (Tilapia—Oreochromis niloticus) exposed to the toxin under laboratory condition. Among the morphological changes, disorganized parenchymal architecture in the liver, dilated Bowman's space in the kidney, fibrolysis in the heart, necrotic enteritis in the intestines, and hemorrhages in the gills, were observed. Moreover, some oxidative stress biomarkers in the liver and kidney of tilapias were altered. Thus, CYN exposure induced increased protein oxidation products in both organs, NADPH oxidase activity was significantly increased with the kidney being the most affected organ, and decreased GSH contents were also detected in both organs, at the higher dose assayed. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:31 pm CET

Cytotoxicity and apoptosis induction by nanoscale talc particles from two different geographical regions in human lung epithelial cells

Abstract

We have characterized the physicochemical properties of nanotalc particles from two different geographical regions and examined their toxicity mechanisms in human lung epithelial (A549) cells. Indigenous nanotalc (IN) of Indian origin and commercial nanotalc (CN) of American origin were used in this study. Physicochemical properties of nanotalc particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), Brunauer-Emmet-Teller (BET), and dynamic light scattering (DLS). Results showed that both IN and CN particles significantly induce cytotoxicity and alteration in cell cycle phases. Both IN and CN particles were found to induce oxidative stress indicated by induction of reactive oxygen species (ROS), lipid peroxidation, and depletion of antioxidant levels. DNA fragmentation and caspase-3 enzyme activation due to IN and CN particles exposure were also observed. We further showed that after iron chelation, IN and CN particles produce significantly less cytotoxicity, oxidative stress, and genotoxicity to A549 cells as compared with nonchelated particles. In conclusion, this study demonstrated that redox active iron plays significant role in the toxicity of IN and CN particles, which may be mediated through ROS generation and oxidative stress. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 13 Feb 2012 | 12:31 pm CET

Cloperastine rescues impairment of passive avoidance response in mice prenatally exposed to diethylstilbestrol

Abstract

We previously reported that prenatal exposure to diethylstilbestrol (DES) impaired passive avoidance responses in mice. Apart from the above, we also found that cloperastine, a centrally acting antitussive, ameliorated depression-like and anxiety-like behaviors in rodents at antitussive-effective doses. In this study, we investigated whether or not cloperastine rescues impairment of passive avoidance responses in mice prenatally exposed to DES. Male DES-exposed mice were subcutaneously administered cloperastine at 10 or 30 mg/kg twice a day from 32 to 41 days after birth and subjected to behavioral testing 42 to 46 days after birth. Cloperastine at 10 and 30 mg/kg ameliorated DES-induced impairment of passive avoidance responses. In addition, cloperastine affected the levels of 5-HT1A receptors, GIRK and BDNF in the hippocampus of DES-exposed mice. However, the number of BrdU-positive cells in the hippocampus of DES-exposed mice was not changed by chronic administration of cloperastine. These findings suggest that the action of endocrine disruptors in the brain may not always be irreversible, and that the symptoms caused by endocrine disruptors might be curable with drugs such as cloperastine. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:45 am CET

Exposure to 17α-ethinylestradiol decreases motility and ATP in sperm of male fighting fish Betta splendens

Abstract

The synthetic estrogen 17α-ethinylestradiol (EE2) is an endocrine-disrupting chemical released into aquatic environments from sewage treatment facilities. We tested the effects of two environmentally relevant concentrations of waterborne EE2, 10 and 100 ng L−1, on reproductive endpoints in the teleost fish Betta splendens. In the first experiment, testes were removed from males and sperm were exposed to EE2 directly through the activation water. Direct exposure to EE2 had no effect on any measure of sperm swimming performance. In the second experiment, we exposed sexually mature male B. splendens to EE2 using a semi-static exposure protocol for 4 weeks. There were no significant treatment effects in the 10 ng L−1 treatment group, but at the 100 ng L−1 dose we found that fish had smaller gonads and reduced sperm swimming velocity. When allowed to interact freely with female conspecifics, males exposed to 100 ng L−1 EE2 built smaller nests and showed a nonsignificant decrease in fertilization success. To investigate further the potential mechanism underlying the decrease in sperm quality, we repeated the chronic exposure experiment and analyzed the ATP content of sperm from fish in each treatment group. We found that males exposed to 100 ng L−1 of EE2 had fewer moles of ATP per sperm than did fish in the other two treatment groups, suggesting that a decrease in intracellular ATP caused a reduction in sperm swimming velocity. The current study adds to the growing body of literature that indicates the risks to aquatic organisms of exposure to environmentally relevant concentrations of EE2. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:44 am CET

Organic insecticide spinosad causes in vivo oxidative effects in the brain of Oreochromis niloticus

Abstract

Spinosad is an organic insecticide derived from a naturally occurring soil bacterium and is used in organic farming worldwide. The aim of this study was to evaluate in vivo toxic effects of spinosad in the brain of Oreochromis niloticus as a model organism. The fish were exposed to sublethal spinosad concentrations (25, 50, 75 mg L−1) for 24–48–72 h to determine tGSH, GSH, GSSG, and TBARS contents, GSH/GSSG ratio, and GPx, GR, GST enzymes activities using spectrophotometrical methods, and Hsp70 content by an ELISA technique. Spinosad caused elevations in the contents of tGSH, GSH, GSSG, Hsp70, and reductions in the ratio of GSH/GSSG and GPx activity and an induction in the GR activity. The results indicated that spinosad had oxidative effects in the brain tissue by altering the parameters in GSH-related antioxidant system and Hsp70. It was also suggested that spinosad-induced free-radicals were eliminated by GSH-related antioxidant system in the brain of Oreochromis niloticus. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:44 am CET

Affinity purification using recombinant PXR as a tool to characterize environmental ligands

Abstract

Many environmental endocrine disrupting compounds act as ligands for nuclear receptors. The human pregnane X receptor (hPXR), for instance, is activated by a variety of environmental ligands such as steroids, pharmaceutical drugs, pesticides, alkylphenols, polychlorinated biphenyls and polybromo diethylethers. Some of us have previously reported the occurrence of hPXR ligands in environmental samples but failed to identify them. The aim of this study was to test whether a PXR-affinity column, in which recombinant hPXR was immobilized on solid support, could help the purification of these chemicals. Using PXR ligands of different affinity (10 nM < EC50 < 10 μM), we demonstrated that the PXR-affinity preferentially column captured ligands with medium to high affinities (EC50 < 1 μM). Furthermore, by using the PXR-affinity column to analyze an environmental sample containing ERα, AhR, AR, and PXR activities, we show that (i) half of the PXR activity of the sample was due to compounds with medium to high affinity for PXR and (ii) PXR shared ligands with ERα, AR, and AhR. These findings demonstrate that the newly developed PXR-affinity column coupled to reporter cell lines represents a valuable tool for the characterization of the nature of PXR active compounds and should therefore guide and facilitate their further analysis. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:44 am CET

Cell cycle deregulation by methyl isocyanate: Implications in liver carcinogenesis

Abstract

Liver is often exposed to plethora of chemical toxins. Owing to its profound physiological role and central function in metabolism and homeostasis, pertinent succession of cell cycle in liver epithelial cells is of prime importance to maintain cellular proliferation. Although recent evidence has displayed a strong association between exposures to methyl isocyanate (MIC), one of the most toxic isocyanates, and neoplastic transformation, molecular characterization of the longitudinal effects of MIC on cell cycle regulation has never been performed. Here, we sequentially delineated the status of different proteins arbitrating the deregulation of cell cycle in liver epithelial cells treated with MIC. Our data reaffirms the oncogenic capability of MIC with elevated DNA damage response proteins pATM and γ-H2AX, deregulation of DNA damage check point genes CHK1 and CHK2, altered expression of p53 and p21 proteins involved in cell cycle arrest with perturbation in GADD-45 expression in the treated cells. Further, alterations in cyclin A, cyclin E, CDK2 levels along with overexpression of mitotic spindle checkpoints proteins Aurora A/B, centrosomal pericentrin protein, chromosomal aberrations, and loss of Pot1a was observed. Thus, MIC impacts key proteins involved in cell cycle regulation to trigger genomic instability as a possible mechanism of developmental basis of liver carcinogenesis. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:24 am CET

Excitotoxicity and oxidative damages induced by methylmercury in rat cerebral cortex and the protective effects of tea polyphenols

Abstract

Methylmercury (MeHg) is a highly neurotoxic environmental pollutant that has a high appetency to the central nervous system. The underlying mechanisms of MeHg-induced neurotoxicity have not been elucidated clearly until now. Therefore, to explore the mechanisms contribute to MeHg-induced neurotoxicity, rats were exposed to different dosage of methylmercury chloride (CH3ClHg) (0, 4, and 12 μmol kg−1) for 4 weeks to evaluate the neurotoxic effects of MeHg. In addition, considering the antioxidative properties of tea polyphenols (TP), 1 mmol kg−1 TP was pretreated to observe the possible protective effects on MeHg-induced neurotoxicity. Then Hg, glutamate (Glu) and glutamine (Gln) levels, glutamine synthetase (GS), phosphate-activated glutaminase (PAG), Na+-K+-ATPase, and Ca2+-ATPase activities, intracellular Ca2+ level were examined, glutathione (GSH), malondialdehyde (MDA), protein sulfhydryl, carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and reactive oxygen species (ROS) levels, N-methyl-D-aspartate receptors (NMDARs) mRNA and protein expressions, apoptosis level and morphological changes in the cerebral cortex were also investigated. Study results showed that compared with those in control, exposure to CH3ClHg resulted in excitotoxicity in a concentration-dependent manner, which was shown by the Glu-Gln cycle disruption and intracellular Ca2+ homeostasis disturbance. On the other hand, CH3ClHg exposure resulted in oxidative damages of brain, which were supported by the significant changes on GSH, MDA, sulfhydryl, carbonyl, 8-OHdG, and ROS levels. Moreover, apoptosis rate increased obviously and many morphological changes were found after CH3ClHg exposure. Furthermore, this research indicated that TP pretreatment significantly mitigated the toxic effects of MeHg. In conclusion, findings from this study indicated that exposure to MeHg could induce excitotoxicity and oxidative damage in cerebral cortex while TP might antagonize the MeHg-induced neurotoxicity. © 2011 Wiley Periodicals, Inc. Environ Toxicol 21:, 2011.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:23 am CET

Spatial learning and memory impairment and pathological change in rats induced by acute exposure to microcystin-LR

Abstract

Microcystin-LR (MCLR) is a commonly encountered blue–green algal hepatotoxin and a known inhibitor of cellular protein phosphatase. However, little is known about its neurotoxicity. By using Morris water maze, histopathological and biochemical analysis, we investigated MCLR-induced neurotoxicity on the hippocampus of rat brain. After rats were intrahippocampally injected with MCLR (1 and 10 μg/L), their learning and memory function was greatly impaired, suggesting the neurotoxic potential of MCLR. Meanwhile, obvious histological and ultrastructural injuries and serious oxidative damage were also observed in the hippocampus. These results suggested that oxidative stress might be involved in the MCLR-induced pathological damage in hippocampus, subsequently leading to the spatial learning and memory deficit of rat. Taken together, our results highlighted the MCLR-induced neurotoxicity in the rat, as well as the importance of oxidative stress and pathological impairment in this procedure. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:23 am CET

Protein phosphatases 2A as well as reactive oxygen species involved in tributyltin-induced apoptosis in mouse livers

Abstract

Tributyltin (TBT), a highly toxic environmental contaminant, has been shown to induce caspase-3-dependent apoptosis in human amniotic cells through protein phosphatase 2A (PP2A) inhibition and consequent JNK activation. This in vivo study was undertaken to further verify the results derived from our previous in vitro study. Mice were orally dosed with 0, 10, 20, and 60 mg/kg of body weight TBT, and levels of PP2A, reactive oxygen species (ROS), mitogen-activated protein kinase (MAPK), Bax/Bcl-2, and caspase-3 were detected in the mouse livers. Apoptosis was also evaluated using the TUNEL assay. The results showed that PP2A activity was inhibited, ROS levels were elevated, and MAPKs including ERK, JNK, and p38 were activated in mouse livers treated with the highest dose of TBT. Additionally, the ratio of Bax/Bcl-2 was increased, caspase-3 was activated, and apoptosis in mouse livers could be detected in the highest dose group. Therefore, a possible signaling pathway in TBT-induced apoptosis in mouse livers involves PP2A inhibition and ROS elevation serving a pivotal function as upstream activators of MAPKs; activation of MAPKs in turn leads to an increase in the Bax/Bcl-2 ratio, ultimately leading to the activation of caspase-3. The results give a comprehensive and novel description of the mechanism of TBT-induced toxicity. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 6 Jan 2012 | 5:23 am CET

Acetaminophen increases the risk of arsenic-mediated development of hepatic damage in rats by enhancing redox-signaling mechanism

Abstract

We evaluated whether the commonly used analgesic-antipyretic drug acetaminophen can modify the arsenic-induced hepatic oxidative stress and also whether withdrawal of acetaminophen administration during the course of long-term arsenic exposure can increase susceptibility of liver to arsenic toxicity. Acetaminophen was co-administered orally to rats for 3 days following 28 days of arsenic pre-exposure (Phase-I) and thereafter, acetaminophen was withdrawn, but arsenic exposure was continued for another 28 days (Phase-II). Arsenic increased lipid peroxidation and reactive oxygen species (ROS) generation, depleted glutathione (GSH), and decreased superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione reductase (GR) activities. Acetaminophen caused exacerbation of arsenic-mediated lipid peroxidation and ROS generation and further enhancement of serum alanine aminotransferase and aspartate aminotransferase activities. In Phase-I, acetaminophen caused further GSH depletion and reduction in SOD, catalase, GPx and GR activities, but in Phase-II, only GPx and GR activities were more affected. Arsenic did not alter basal and inducible nitric oxide synthase (iNOS)-mediated NO production, but decreased constitutive NOS (cNOS)-mediated NO release. Arsenic reduced expression of endothelial NOS (eNOS) and iNOS genes. Acetaminophen up-regulated eNOS and iNOS expression and NO production in Phase-I, but reversed these effects in Phase-II. Results reveal that acetaminophen increased the risk of arsenic-mediated hepatic oxidative damage. Withdrawal of acetaminophen administration also increased susceptibility of liver to hepatotoxicity. Both ROS and NO appeared to mediate lipid peroxidation in Phase-I, whereas only ROS appeared responsible for peroxidative damage in Phase-II. © 2011 Wiley-Liss, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 25 Nov 2011 | 10:17 am CET

Molecular and cellular effects of chemicals disrupting steroidogenesis during early ovarian development of brown trout (Salmo trutta fario)

Abstract

A range of chemicals found in the aquatic environment have the potential to influence endocrine function and affect sexual development by mimicking or antagonizing the effects of hormones, or by altering the synthesis and metabolism of hormones. The aim of this study was to evaluate whether the effects of chemicals interfering with sex hormone synthesis may affect the regulation of early ovarian development via the modulation of sex steroid and insulin-like growth factor (IGF) systems. To this end, ex vivo ovary cultures of juvenile brown trout (Salmo trutta fario) were exposed for 2 days to either 1,4,6-androstatriene-3,17-dione (ATD, a specific aromatase inhibitor), prochloraz (an imidazole fungicide), or tributyltin (TBT, a persistent organic pollutant). Further, juvenile female brown trout were exposed in vivo for 2 days to prochloraz or TBT. The ex vivo and in vivo ovarian gene expression of the aromatase (CYP19), responsible for estrogen production, and of IGF1 and 2 were compared. Moreover, 17β-estradiol (E2) and testosterone (T) production from ex vivo ovary cultures was assessed. Ex vivo exposure to ATD inhibited ovarian E2 synthesis, while T levels accumulated. However, ATD did not affect ex vivo expression of cyp19, igf1, or igf2. Ex vivo exposure to prochloraz inhibited ovarian E2 production, but did not affect T levels. Further prochloraz up-regulated igf1 expression in both ex vivo and in vivo exposures. TBT exposure did not modify ex vivo synthesis of either E2 or T. However, in vivo exposure to TBT down-regulated igf2 expression. The results indicate that ovarian inhibition of E2 production in juvenile brown trout might not directly affect cyp19 and igf gene expression. Thus, we suggest that the test chemicals may interfere with both sex steroid and IGF systems in an independent manner, and based on published literature, potentially lead to endocrine dysfunction and altered sexual development. © 2011 Wiley-Liss, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 25 Nov 2011 | 4:57 am CET

Antioxidant effect of propolis against exposure to chromium in Cyprinus carpio

Abstract

The aim of the present study was to investigate the ameliorative properties of propolis against the toxic effects of chromium (VI) by examining oxidative damage markers such as lipid peroxidation and the antioxidant defence system components in carp (Cyprinus carpio). The fish were exposed to sublethal concentrations of chromium. Propolis was simultaneously administered to chromium-exposed fish. Treatment was continued for 28 days, and at the end of this period, blood and tissue (liver, kidney, spleen, and gill) samples were collected. Levels of malondialdehyde (MDA) and reduced glutathione (GSH) as well as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were determined in blood and tissues for measurement of oxidant–antioxidant status. The levels of MDA, as an index of lipid peroxidation, increased in blood and tissues. Antioxidant enzyme activities in blood and tissues were modified in chromium groups compared to controls. Simultaneous administration of propolis ameliorated these parameters. The present results suggest that administration of propolis might alleviate chromium-induced oxidative stress. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 Nov 2011 | 8:17 am CET

Silymarin prevents the toxicity induced by benzo(a)pyrene in human erythrocytes by preserving its membrane integrity: An in vitro study

Abstract

Silymarin, the purified extract from milk thistle Silybum marianum (L.) Gaertn, consists mainly of four isomeric flavonolignans: silibinin, isosilibinin, silidianin, and silichristin. The present study was carried out to evaluate the protective potential of silymarin in human erythrocytes against in vitro exposure to the carcinogen benzo(a)pyrene (B(a)P). Erythrocytes isolated from human blood were divided into four groups and treated with Vehicle [Group I], B(a)P (300 μM) [Group II], Silymarin (500 μM) + B(a)P (300 μM) [Group III], and Silymarin alone (500 μM)] [Group IV]. Silymarin treatment maintains the integrity of erythrocytes by preventing hemolysis, protein thiol oxidation and by decreasing the activity of AChE. SEM observations indicate that B(a)P induced significant alteration in the morphology of erythrocytes to echinocytes, which may be due to the interaction of B(a)P with the membrane's outer phopholipid monolayer. The light microscopic and SEM images show that silymarin treatment maintains the normal discocytic morphology of erythrocytes. The protective effect of silymarin might be attributed to its chemical structure and membranotrophic nature. The components silibinin, silydianin, and silychristin have OH in the 3rd, 5th, and 7th carbon atoms that may account for its increased antioxidant activity and removal of ROS formed during B(a)P metabolism. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Nov 2011 | 1:35 pm CET

Stage-dependent toxicity of bisphenol a on Rhinella arenarum (anura, bufonidae) embryos and larvae

Abstract

The acute and chronic toxicity of bisphenol A (BPA) was evaluated on the common South American toad Rhinella arenarum embryos and larvae by means of continuous and pulse exposure treatments. Embryos were treated continuously from early blastula (S.4) up to complete operculum (S.25), during early larval stages and by means of 24 h pulse exposures of BPA in concentrations ranging between 1.25 and 40 mg L−1, in order to evaluate the susceptibility to this compound in different developmental stages. For lethal effects, S.25 was the most sensitive and gastrula was the most resistant to BPA. The Teratogenic Index for neurula, the most sensitive embryonic stage for sublethal effects was 4.7. The main morphological alterations during early stages were: delayed or arrested development, reduced body size, persistent yolk plug, microcephaly, axial/tail flexures, edemas, blisters, waving fin, underdeveloped gills, mouth malformations, and cellular dissociation. BPA caused a remarkable narcotic effect from gill circulation stage (S.20) onwards in all the organisms exposed after 3 h of treatment with 10 mg L−1 BPA. After recovering, the embryos exhibited scarce response to stimuli, erratic or circular swimming, and spasmodic contractions from 5 mg L−1 onwards. Our results highlight the lethal and sublethal effectsof BPA on R. arenarum embryos and larvae, in the last case both at structural and functional levels. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Nov 2011 | 1:34 pm CET

Effects of malachite green on the mRNA expression of detoxification-related genes in Nile tilapia (Oreochromis niloticus) and other major Chinese freshwater fishes

Abstract

The use of malachite green (MG) in fish farming is prohibited in China due to its potentially toxicological and carcinogenic nature, but it is still illegally used in some places. The aim of this study was to investigate the time and concentration-dependent responses of xenobiotic metabolizing and detoxification-related genes in diverse fishes exposed to MG both in vivo and in vitro. Experimental fish were administered to two exposure groups of malachite green (MG) (0.10 and 0.50 mg L−1) for 8 h. The hepatocytes isolated from Nile tilapia were incubated with MG (0.5, 1.0, and 2.0 mg L−1) for 8 and 24 h, respectively. In vivo, exposure to 0.10 and 0.50 mg L−1 MG for 8 h caused significant changes of the detoxification-related genes on the mRNA expression levels. Low-concentration (0.10 mg L−1) level of MG induced significant increase on the mRNA expression level of GSTR gene in Nile tilapia and other fishes. The mRNA expression of grass carp UCP2 was significantly induced when exposed to 0.5 mg L−1 MG. However, the mRNA expression levels of GSTA, CYP1A, and GPX were inhibited significantly by 0.5 mg L−1 MG in Nile tilapia, grass carp, and Taiwan snakehead. In vitro, the significant increase of mRNA expression of these genes was detected after exposure to 0.5 mg L−1 MG (UCP2), and 1.0 mg L−1 MG (CYP1A1, GSTA, GSTR, and UCP2). The induction of hepatic CYP1A1, GSTA, GSTR, and UCP2 in response to MG suggested a potential role of fish CYP1A1, GSTA, GSTR, and UCP2 in MG metabolism. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Nov 2011 | 1:34 pm CET

Acute and chronic toxicity of chromium and cadmium to the tropical cladoceran pseudosida ramosa and the implications for ecotoxicological studies

Abstract

In this study, the acute and chronic toxicity of the metals chromium and cadmium were tested against the tropical freshwater cladoceran Pseudosida ramosa. Acute tests showed that the 48-h LC50 of chromium was 29 μg L−1, while that of cadmium was 12 μg L−1. P. ramosa had a similar sensitivity to those of other cladoceran species cultured in the same conditions as in this study, or a higher sensitivity when water hardness was raised. Long-term chronic exposure of P. ramosa to chromium decreased maternal survival, fecundity, and fertility at a concentration of 10 μg L−1. For cadmium, reductions in the same endpoints were observed at a concentration of 3 μg L−1. Moreover, the degree of toxicity of the chromium and cadmium to P. ramosa after release of the first brood was similar to the result obtained after 21 days, using reproduction as the endpoint. Brazilian water bodies located near industrial areas already show concentrations of chromium and cadmium higher than levels causing acute and chronic toxicity to P. ramosa in our study. Many water quality criteria in tropical regions are based on ecotoxicological tests with non-native species and, consequently, this may lead to errors of interpretation when the permitted maximum levels of for each toxic substance are established. Therefore, we reinforce the idea of using native species to establish the maximum concentrations of toxic substances in water quality criteria, especially for metals, since their effects are related to water hardness, pH, and temperature specific to each region. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 29 Oct 2011 | 1:43 pm CEST

Potassium bromate causes cell lysis and induces oxidative stress in human erythrocytes

Abstract

In the present study, we have studied the effect of KBrO3 on human erythrocytes under in vitro conditions. Erythrocytes were isolated from the blood of healthy nonsmoking volunteers and incubated with different concentrations of KBrO3 at 37°C for 60 min. This resulted in marked hemolysis in a KBrO3-concentration dependent manner. Lysates were prepared from KBrO3-treated and control erythrocytes and assayed for various parameters. KBrO3 treatment caused significant increase in protein oxidation, lipid peroxidation, hydrogen peroxide levels, and decrease in total sulfhydryl content, which indicates induction of oxidative stress in human erythrocytes. Methemoglobin levels and methemoglobin reductase activity were significantly increased while the total antioxidant power of lysates was greatly reduced upon KBrO3 treatment. Intracellular production of reactive oxygen species increased in a dose dependent manner. Exposure of erythrocytes to KBrO3 also caused decrease in the activities of catalase, glutathione peroxidase, thioredoxin reductase, glucose 6-phosphate dehydrogenase and glutathione reductase whereas the activities of Cu-Zn superoxide dismutase and glutathione-S-transferase were increased. These results show that KBrO3 induces oxidative stress in human erythrocytes through the generation of reactive oxygen species and alters the cellular antioxidant defense system. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 19 Oct 2011 | 2:14 pm CEST

DNA damage and repair following In vitro exposure to two different forms of titanium dioxide nanoparticles on trout erythrocyte

Abstract

TiO2 has been widely used to promote organic compounds degradation on waste aqueous solution, however, data on TiO2 nanotoxicity to aquatic life are still limited. In this in vitro study, we compare the toxicity of two different families of TiO2 nanoparticles on erythrocytes from Oncorhynchus mykiss trout. The crystal structure of the two TiO2 nanoparticles was analyzed by XRD and the results indicated that one sample is composed of TiO2 in the anatase crystal phase, while the other sample contains a mixture of both the anatase and the rutile forms of TiO2 in a 2:8 ratio. Further characterization of the two families of TiO2 nanoparticles was determined by SEM high resolution images and BET technique. The toxicity results indicate that both TiO2 nanoparticles increase the hemolysis rate in a dose dependent way (1.6, 3.2, 4.8 μg mL−1) but they do not influence superoxide anion production due to NADH addition measured by chemiluminescence. Moreover, TiO2 nanoparticles (4.8 μg mL−1) induce DNA damage and the entity of the damage is independent from the type of TiO2 nanoparticles used. Modified comet assay (Endo III and Fpg) shows that TiO2 oxidizes not only purine but also pyrimidine bases. In our experimental conditions, the exposure to TiO2 nanoparticles does not affect the DNA repair system functionality. The data obtained contribute to better characterize the aqueous environmental risks linked to TiO2 nanoparticles exposure. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 19 Oct 2011 | 2:13 pm CEST

Effects of low-dose exposure to pesticide mixture on physiological responses of the pacific oyster, Crassostrea gigas

Abstract

This study investigated the effects on the physiology of Pacific oyster, Crassostrea gigas, of a mixture of pesticides containing 0.8 μg L−1 alachlor, 0.6 μg L−1 metolachlor, 0.7 μg L−1 atrazine, 0.6 μg L−1 terbuthylazine, 0.5 μg L−1 diuron, 0.6 μg L−1 fosetyl aluminum, 0.05 μg L−1 carbaryl, and 0.7 μg L−1 glyphosate for a total concentration of 4.55 μg L−1. The total nominal concentration of pesticides mixture corresponds to the pesticide concentrations in the shellfish culture area of the Marennes-Oleron basin. Two varieties of C. gigas were selected on the foreshore, based on their characteristics in terms of resistance to summer mortality, to assess the effects of the pesticide mixture after 7 days of exposure under controlled conditions. The early effects of the mixture were assessed using enzyme biomarkers of nitrogen metabolism (GS, glutamine synthetase), detoxification metabolism (GST, glutathione S-transferase), and oxidative stress (CAT, catalase). Sublethal effects on hemocyte parameters (phagocytosis and esterase activity) and DNA damages (DNA adducts) were also measured. Changes in metabolic activities were characterized by increases in GS, GST, and CAT levels on the first day of exposure for the “resistant†oysters and after 3–7 days of exposure for the “susceptible†oysters. The formation of DNA adducts was detected after 7 days of exposure. The percentage of hemocyte esterase-positive cells was reduced in the resistant oysters, as was the hemocyte phagocytic capacity in both oyster varieties after 7 days of exposure to the pesticide mixture. This study highlights the need to consider the low doses and the mixture of pesticides to evaluate the effects of these molecules on organisms. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 19 Oct 2011 | 1:58 pm CEST

Comparison of the protective effects of antioxidant compounds in the liver and kidney of Cd- and Cr-exposed common carp

Abstract

The aim of this study was to see whether the taurine (TAU), alpha-lipoic acid (LA), curcumin (CUR), and N-acetylcysteine (NAC) protection against oxidative stress caused by heavy metals is owed to the metal-decreasing or antioxidative effect. In this context, liver and kidney tissues of common carp (Cyprinus carpio carpio L.) were exposed in vivo to model toxicants cadmium (Cd) and chromium (Cr). The tissues were dissected 96 h after intraperitoneal injection of the metals and antioxidant substances. Cd and Cr levels were determined in the liver using the ICP-OES, but we could not obtain enough kidney tissue to make the same measurements in the kidney. The enzymatic activities of SOD, CAT, and GPx, and the GSH redox status and lipid peroxidation levels were analyzed using spectrophotometric methods. Of all investigated antioxidants, only NAC decreased metal levels in the liver. Cd had little effect on oxidative stress parameters, while Cr showed a weak prooxidative effect. Cotreatment with TAU/LA/CUR/NAC and Cr significantly increased liver SOD activity. Chromium induced kidney SOD and CAT, but all antioxidants lowered CAT activity. Cadmium reduced liver and increased kidney GSSG. NAC increased liver GSH, but the increase did not correlate with decrease in Cd. Curcumin given with Cd increased kidney and decreased liver lipid peroxidation, whereas TAU with Cr increased lipid peroxidation in both tissues. N-Acetylcysteine was the most effective antioxidative agent, owing to its metal-decreasing function as well as to its effects on the GSH redox status. We believe that the investigated antioxidant substances which may have been involved in the reduction of Cr caused an increase in SOD activity and a decrease in CAT activity. Changes in the GSSG levels in both tissues might be an adaptive response to the prooxidative potential of Cd. Because of their respective tissue- and metal-dependent prooxidative effects, CUR and TAU deserve particular attention in regard to their use against metal toxicity, Cr in particular. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 11 Oct 2011 | 7:07 am CEST

Pesticide induced alterations in marrow physiology and depletion of stem and stromal progenitor population: An experimental model to study the toxic effects of pesticide

Abstract

Long-term exposure of agriculturally used organochloride and organophosphate pesticides have been shown to cause long-lasting hematotoxicity and increased incidence of aplastic anemia in humans. The mechanisms involved in pesticide induced hematotoxicity and the features of toxicity that may play a major role in bone marrow suppression are not known. The aim of the present study was to investigate the hematological consequences of pesticide exposure in swiss albino mice exposed to aqueous mixture of common agriculturally used pesticides for 6 h/day, 5 days/week for 13 weeks. After the end of last exposure, without a recovery period, the strong hematotoxic effect of pesticide was assessed in mice with long-term bone marrow explant culture (LTBMC-Ex) system and cell colony forming assays. Bone marrow explant culture from the pesticide exposed group of mice failed to generate a supportive stromal matrix and did not produce adequate number of hematopoietic cells and found to contain largely the adipogenic precursors. The decreased cell colony numbers in the pesticide exposed group indicated defective maturational and functional status of different marrow cell lineages. As a whole, exposure of mice to the mixture of pesticides reduced the total number of bone marrow cells (granulocytes are the major targets of pesticide toxicity), hematopoietic, and non-hematopoietic progenitor cells and most of the hematological parameters. Replication of primitive stem/progenitor cells in the marrow was decreased following pesticide exposure with G0/G1-phase arrest of most of the cells. The progenitor cells showed decreased percentage of cells in S/G2/M-phase. The increased apoptosis profile of the marrow progenitors (Increased CD95 expression) and primitive stem cells (High Annexin-V positivity on Sca1+ cells) with an elevated intracellular cleaved caspase-3 level on the Sca1+ bone marrow cells provided the base necessary for explaining the deranged bone marrow microenvironmental structure which was evident from scanning electron micrographs. These results clearly indicate a strong, long lasting toxic effect of pesticides on the bone marrow microenvironment and different microenvironmental components which ultimately leads to the formation of a degenerative disease like aplastic anemia. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 11 Oct 2011 | 7:06 am CEST

Attenuation of low dose methylmercury and glutamate induced-cytotoxicity and tau phosphorylation by an N-methyl-D-aspartate antagonist in human neuroblastoma (SHSY5Y) cells

Abstract

Methylmercury (MeHg), a known neurotoxin, has been reported to alter glutamate homeostasis in the neuronal environment resulting in excitotoxicity. This study was conducted to investigate whether, and if so, under what conditions, that low dose MeHg would enhance the toxicity of glutamate and to what extent that blockade of NMDA receptors would alter MeHg and glutamate's toxicity in cultured neuroblastoma cells. Neuroblastoma cells (SH-SY5Y) were used in a cell culture model to study effects of MeHg, glutamate (glu), a calcium chelator (BAPTA-AM), and a noncompetitive NMDA antagonist, MK-801 on cell growth, cell survival, and phosphorylation of tau protein, as a measure of cellular events associated with tauopathies. Exposure of cells to a combination of MeHg (50 nM) and glutamate (1 mM) resulted in both a greater decrease in cell viability as well as a greater induction in tau phosphorylation, as compared to exposures with MeHg and glutamate alone. MK-801, an NMDA receptor antagonist, and the intracellular calcium chelator, BAPTA-AM, both significantly inhibited tau hyperphosphorylation and protected cells from the effects of combination exposures to glutamate and MeHg. These results may indicate that exposure to even nontoxic levels of MeHg may prime neuronal cells to be more susceptible to neuronal injury from excitotoxicants such as glutamate and thus may increase the likelihood of neurological disease states. In conclusion, low-dose MeHg-induced toxicity may be related to an increase in the cellular response to glutamate and that NMDA receptor antagonists may provide a potential treatment for MeHg-associated neurological diseases. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 5 Oct 2011 | 9:24 am CEST

Effects of di(2-ethylhexyl)phthalate on testicular oxidant/antioxidant status in selenium-deficient and selenium-supplemented rats

Abstract

Di(ethylhexyl)phthalate (DEHP), the most widely used plasticizer, was investigated to determine whether an oxidative stress process was one of the underlying mechanisms for its testicular toxicity potential. To evaluate the effects of selenium (Se), status on the toxicity of DEHP was further objective of this study, as Se is known to play a critical role in testis and in the modulation of intracellular redox equilibrium. Se deficiency was produced in 3-weeks-old Sprague–Dawley rats feeding them ≤0.05 mg Se /kg diet for 5 weeks, and Se-supplementation group was on 1 mg Se/kg diet. DEHP-treated groups received 1000 mg/kg dose by gavage during the last 10 days of the feeding period. Activities of antioxidant selenoenzymes [glutathione peroxidase 1 (GPx1), glutathione peroxidase 4 (GPx4), thioredoxin reductase (TrxR)], catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST); concentrations of reduced glutathione (GSH), oxidized glutathione (GSSG), and thus the GSH/GSSG redox ratio; and thiobarbituric acid reactive substance (TBARS) levels were measured. DEHP was found to induce oxidative stress in rat testis, as evidenced by significant decrease in GSH/GSSG redox ratio (>10-fold) and marked increase in TBARS levels, and its effects were more pronounced in Se-deficient rats with ∼18.5-fold decrease in GSH/GSSG redox ratio and a significant decrease in GPx4 activity, whereas Se supplementation was protective by providing substantial elevation of redox ratio and reducing the lipid peroxidation. These findings emphasized the critical role of Se as an effective redox regulator and the importance of Se status in protecting testicular tissue from the oxidant stressor activity of DEHP. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 5 Oct 2011 | 9:24 am CEST

The impact of paracetamol on selected biomarkers of the mollusc species Corbicula fluminea

Abstract

The Asian clam Corbicula fluminea is an invasive bivalve that has recently spread in Europe and currently represents a large portion of the aquatic biomass in specific areas. Because of the impacts that the species may have in invaded ecosystems, increased knowledge on the physiologic features of the species life-cycle under different environmental scenarios (e.g., contamination events) is critical to understand the dynamics of the invasion and resulting ecosystem imbalance. The presence of pharmaceutical residues in the aquatic environment has recently received great attention since high levels of contamination have been found, not only in sewage treatment plant effluents, but also in open waters. The present article reports toxicological biochemical effects of paracetamol to Corbicula fluminea following short- and long-term exposures. Oxidative stress parameters were specially focused namely catalase (CAT), glutathione S-transferases (GSTs), and glutathione reductase (GRed). The effect of tested substances on lipid peroxidation was also investigated. Paracetamol did not induce alterations on CAT activity, caused a significant decrease of GSTs activity following short- and long-term exposure (LOEC values of 532.78 mg L−1 and 30.98 μg L−1, respectively), and was responsible for a significant and dose-dependent decrease of GRed activity in short- and long-term exposures. These results indicate that exposure to paracetamol can provoke significant alterations on the cellular redox status of C. fluminea. 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 29 Sep 2011 | 9:09 am CEST

Exogenous application of salicylic acid to alleviate the toxic effects of insecticides in Vicia faba L

Abstract

The present study investigated the possible mediatory role of salicylic acid (SA) in protecting plants from insecticides toxicity. The seeds of Vicia faba var IIVR Selection-1 were treated with different concentrations (1.5, 3.0, and 6.0 ppm) of the insecticides alphamethrin (AM) and endosulfan (ES) for 6 h with and without 12 h conditioning treatment of SA (0.01 mM). Insecticides treatment caused a significant decrease in mitotic index (MI) and induction of different types of chromosomal abnormalities in the meristematic cells of broad bean roots. Pretreatment of seeds with SA resulted in increased MI and significant reduction of chromosomal abnormalities. SA application also regulated proline accumulation and carotenoid content in the leaf tissues. SA resulted in the decrement of insecticides induced increase in proline content and increased the carotenoids content. These results illustrate the ameliorating effect of SA under stress conditions and reveal that SA is more effective in alleviating the toxic effects of insecticides at higher concentrations than that at lower concentrations. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 26 Sep 2011 | 9:03 am CEST

Effects of benzene and its metabolites on global DNA methylation in human normal hepatic l02 cells

Abstract

Benzene is an important industrial chemical that is also widely present in cigarette smoke, automobile exhaust, and gasoline. It is reported that benzene can cause hematopoietic disorders and has been recognized as a human carcinogen. However, the mechanisms by which it increases the risk of carcinogenesis are only partially understood. Aberrant DNA methylation is a major epigenetic mechanism associated with the toxicity of carcinogens. To understand the carcinogenic capacity of benzene, experiments were designed to investigate whether exposure to benzene and its metabolites would change the global DNA methylation status in human normal hepatic L02 cells and then to evaluate whether the changes would be induced by variation of DNA methyltransferase (DNMT) activity in HaeIII DNMT-mediated methylation assay in vitro. Our results showed that hydroquinone and 1,4-benzoquinone could induce global DNA hypomethylation with statistically significant difference from control (p < 0.05), but no significant global DNA methylation changes were observed in L02 cells with benzene, phenol, and 1,2,4-trihydroxybenzene exposure. Benzene metabolites could not influence HaeIII DNMT activity except that 1,4-benzoquinone shows significantly inhibiting effect on enzymatic methylation reaction at concentrations of 5 μM (p < 0.05). These results suggest that benzene metabolites, hydroquinone, and 1,4-benzoquinone can disrupt global DNA methylation, and the potential epigenetic mechanism by which that global DNA hypomethylation induced by 1,4-benzoquinone may work through the inhibiting effects of DNMT activity at 10 μM (p < 0.05). © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 23 Sep 2011 | 6:22 am CEST

A subchronic in situ exposure method for evaluating effects in small-bodied fish at contaminated sites

Abstract

In situ fish-caging studies at contaminated sites can provide information that is more realistic compared to traditional laboratory-based studies. However, few methods have been developed for exposing sentinel fish species for subchronic durations, and fewer still are optimized for exposing small-bodied fish while maintaining fish health and growth throughout the caging trial. Those methods typically lack a feeding regimen during the fish caging trial. While that may be acceptable or even appropriate for typical short-term toxicity testing, it does limit the duration of the exposure, and may not be suitable when post-caging trials or observations are necessary. Returning healthy fish to the lab following the in situ exposure would be important, for example, in studies designed to examine long-term or multigenerational effects following an in situ exposure. In this article we describe a subchronic method for caging small fish at contaminated sites while maintaining growth and reproductive development. Fathead minnow (Pimephales promelas) were caged in situ for 6 weeks, after which time they were returned to the lab where they were evaluated for health and reproductive performance. Growth and reproductive endpoints revealed no adverse effect on fish due to fish caging and related handling, demonstrating the suitability of our caging and feeding method for long-term caging studies. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 20 Sep 2011 | 8:58 am CEST

Immune dysfunction and liver damage of mice following exposure to lanthanoids

Abstract

In an effort to investigate the effects of exposure to lanthanoids (Ln) on the immune response and liver function, mice were orally exposed to LaCl3, CeCl3, and NdCl3 at 2, 10, and 20 mg/kg doses for 30 days, respectively; lymphocyte counts, serum IgM level, hematological indices, biochemical parameters of liver functions, and histopathological changes in Ln3+-treated mice were assessed. Indeed, 20 mg/kg Ln3+ significantly inhibited mice growth and reduced the counts of white blood cells, platelets, and reticulocyte in mice blood. Specifically, in these Ln3+-treated mice, CD3+, CD4+, CD8+, CD19+ and NK cells, and CD4+/CD8+ ratio as well as serum IgM level were decreased. Furthermore, liver function was disrupted, as evidenced by the increased alanine aminotransferase, total bilirubin, total bile acid and triglycerides, and the decreased glucose and ratio of albumin to globulin. The cytoarchitecture damage and fatty degeneration in liver caused by Ln3+ at 20 mg/kg dose were also observed. Our findings showed that exposure to Ln affected the cell and humoral immunity and disturbed liver function in mice. In addition, Ce3+ was found to exhibit higher toxicity than La3+ and Nd3+. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 16 Sep 2011 | 1:36 pm CEST

Developmental toxicity of benzyl benzoate in rats after maternal exposure throughout pregnancy

Abstract

The maternal and fetal toxicity of benzyl benzoate, commonly used as antiparasitic insecticide, was evaluated in pregnant rats after a daily oral dose of 25 and 100 mg/kg. Biochemical, histopathological, and morphological examinations were performed. Dams were observed for maternal body weights and food and water consumption and subjected to caesarean section on (GD) 20. Maternal and fetal liver, kidney, heart, brain, and placenta were examined histopathologically under light microscope. Maternal and fetal liver and placenta were stained immunohistochemically for vascular endothelial growth factor (VEGF). Morphometric analysis of fetal body lengths, placental measurements, and fetal skeletal stainings was performed. Statistically significant alterations in biochemical parameters and placental and skeletal measurements were determined in treatment groups. In addition to histopathological changes, considerable differences were observed in the immunolocalization of VEGF in treatment groups. These results demonstrated that benzyl benzoate and its metabolites can transport to the placenta and eventually enter the fetuses. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 16 Sep 2011 | 12:58 pm CEST

Bufalin-inhibited migration and invasion in human osteosarcoma U-2 OS cells is carried out by suppression of the matrix metalloproteinase-2, ERK, and JNK signaling pathways

Abstract

Bufalin has been shown to exhibit multiple pharmacological activities, including induction of apoptosis in many types of cancer cell lines. Osteosarcoma is a type of cancer which is difficult to treat and the purpose of this study was to investigate the effects of bufalin on the migration and invasion of human osteosarcoma U-2 OS cells. The wound healing assay and Boyden chamber transwell assay were used for examining the migration of U-2 OS cells. Western blotting and gelatin zymography assays were used for theexpression and activities of metalloproteinase (MMP)-2, MMP-7 or MMP-9 levels. Western blotting analysis also was used for measuring the levels of growth factor receptor-bound protein 2 (GRB2), son of sevenless homolog 1 (SOS1), c-Jun N-terminal kinases 1/2 (JNK1/2), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 in bufalin-treated U-2 OS cells. Bufalin inhibited the cell migration and invasion of U-2 OS cells in vitro. Moreover, bufalin reduced MMP-2 and MMP-9 enzyme activities of U-2 OS cells. Bufalin also suppressed the protein level of MMP-2 and reduced the levels of mitogen-activated protein kinases (MAPKs) such as JNK1/2 and ERK1/2 signals in U-2 OS cells. Our results suggest that signaling pathways for bufalin-inhibited migration and invasion of U-2 OS cells might be mediated through blocking MAPK signaling and resulting in the inhibition of MMP-2. Bufalin could be a useful agent to develop as a novel antitumor agent by virtue of its ability to inhibit tumor cell migration and invasion. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011..

Quelle: Environmental Toxicology | 16 Sep 2011 | 12:57 pm CEST

Ecotoxicological study of arsenic and lead contaminated soils in former orchards at the Hanford site, USA

Abstract

The purpose of this study was to assess ecotoxicity of former orchard soils contaminated with lead arsenate pesticides at the Hanford Site in Washington state (USA). Surface soil, plant, and invertebrate samples were collected from 11 sites in former orchard areas. Mean (standard deviation [SD]) for As and Pb in soil were 39.5 (40.6) and 208 (142) mg/kg dry wt, respectively (n = 11). These concentrations exceeded Hanford background levels but were similar to orchard soils elsewhere. In our study, As and Pb soil concentrations were positively and significantly correlated (r = 0.87, Bonferroni P < 0.05). Speciation of total inorganic As in soil (n = 6) demonstrated that As+5 was the dominant form (>99%). Mean (SD) for As and Pb in cheatgrass were 3.9 (7.9) and 12.4 (20.0) mg/kg dry wt, respectively (n = 11), while mean (SD) for As and Pb in darkling beetles were 5.4 (2.6) and 3.9 (3.0) mg/kg dry wt, respectively (n = 8). Linear regressions were constructed to estimate soil to cheatgrass and soil to darkling beetle uptake for As and Pb. These were significant (Bonferroni P < 0.05) only for cheatgrass versus soil (As) and darkling beetle versus soil (Pb). Standardized lettuce seedling and earthworm bioassays were performed with a subset of soil samples (n = 6). No significant effects (P > 0.05) were observed in lettuce survival or growth nor in earthworm survival or sublethal effects. Based on these bioassays, unbounded no observed effect concentrations (NOECs) in soil for As and Pb were 128 and 390 mg/kg dry wt, respectively. However, our range of soil concentrations generally overlapped a set of ecotoxicological benchmarks reported in the literature. Given uncertainty and limited sampling related to our NOECs, as well as uncertainty in generic benchmarks from the literature, further study is needed to refine characterization of As and Pb ecotoxicity in former orchard soils at the Hanford Site. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 16 Sep 2011 | 12:30 pm CEST

Sublethal toxicity of esbiothrin relationship with total antioxidant status and in vivo genotoxicity assessment in fish (Cyprinus carpio L., 1758) using the micronucleus test and comet assay

Abstract

Esbiothrin, synthetic pyrethroid with quick activity against insects, is widely used against household pests and in public health. Despite widespread use, data on ecotoxicity and genotoxic effects are extremely scarce. The aim of the present study is to evaluate the genotoxic potential of esbiothrin on a model fish species Cyprinus carpio L., 1758 (Pisces: Cyprinidae, koi) using the micronucleus test and comet assay in peripheral blood erythrocytes. Effects of two sublethal exposure concentrations on plasma total antioxidant status (TAS mmol/L), and Hct values were examined. On the basis of the 96 h LC50 data from U.S. EPA ecotox database (32 μg/L) two sublethal exposure concentrations (5 and 10 μg/L) were used together with ethyl methanesulfonate (EMS) (5 mg/L) as positive control. Five fish were used for each dose/duration group (24, 48, and 72 h) under controlled laboratory conditions. The fish showed behavioral changes at the higher dose. Plasma TAS (mmol/L) levels decreased in 24 h; an increase was observed slightly for 48 and obviously for 72 h in both exposure doses. Similarly, hematocrit (Hct) values differed between exposure duration but no significant differences in mean values were found between groups of the same exposure time. The general trend was a rise after 48 h, which decreased afterwards. Our results revealed significant increases in the frequencies of micronuclei and levels of DNA strand breaks and thus demonstrated the genotoxic potential of this pesticide on fish, a nontarget organism of the aquatic ecosystem. To our knowledge this is the first study to report observable genotoxic effects of esbiothrin on fish. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 13 Sep 2011 | 10:47 am CEST

Impairment of the mitochondrial oxidative phosphorylation system and oxidative stress in liver of crucian carp (Carassius auratus L.) exposed to microcystins

Abstract

Hepatotoxic microcystins (MCs) are produced by cyanobacteria in diverse water bodies and the pathophysiology includes induction of reactive oxygen species and adenosine triphosphate (ATP) depletion in cells. In this study, we evaluated MCs induced changes in the oxidative phosphorylation (OXPHOS) system in mitochondria of crucian carp liver. Fish were subdivided into two groups that were intraperitoneally injected with two doses of MCs (50 and 200 MC-LReq μg/kg bw) and were sacrificed at 1, 3, 12, 24, and 48 h postinjection. The activities of five enzyme complexes of electron transport chain and mRNA expression of mitochondrial-encoded genes (cox1, cox2, cox3, and atp6) were significantly reduced in a time-dependent pattern after injection. There were also changes in mitochondrial ultrastructure, decreases in ATPase activities and reduction in antioxidant level after MCs exposure. Disorder in the OXPHOS system and decreased activities of antioxidative enzymes might contribute to bioenergy deficiency and consequent hepatocyte damage induced by MCs. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 13 Sep 2011 | 10:46 am CEST

Effects of decabromodiphenyl ether (BDE-209) on mRNA transcription of thyroid hormone pathway and spermatogenesis associated genes in Chinese rare minnow (Gobiocypris rarus)

Abstract

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants, which are ubiquitous environmental contaminant found in both abiotic and biotic environmental samples. Deca-BDE (BDE-209) is the principal component, which is currently used worldwide. In this study, the effect of BDE-209 on the mRNA levels of thyroid hormone (TH) related genes and spermatogenesis associated genes were determined from larvae and adult rare minnow (Gobiocypris rarus) exposed to concentrations 0.01, 0.1, 1, and 10 μg/L for 21 days. The results showed that the type II deiodinase (dio2) and sodium iodide symporter (nis) mRNA levels were significantly up-regulated in the larvae at 10 μg/L treatment. In adult, histopathological observations showed that liver of female fish were degenerated at 10 μg/L treatment, and inhibition of spermatogenesis were observed in testis of male fish. In addition, the thyroid hormone receptor α (trα), dio2, and nis mRNA levels in the liver of male and female fish were significantly up-regulated, whereas dio2 and nis mRNA levels were significantly down-regulated in the brain. These results indicate that exposure to BDE-209 could result in tissue-specific alternations of TH-related genes expression in adults. Moreover, the mRNA levels of the testis-specific apoptosis genes, the spermatogenesis-associated 4 (spata4) and spermatogenesis-associated 17 (spata17), were down-regulated at 10 μg/L treatment in testis of male fish. Our results suggest that BDE-209 may pose threat to normal thyroid and reproductive function in fish. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Sep 2011 | 3:47 pm CEST

Metals (Ag+, Cd2+, Cr6+) affect ATPase activity in the gill, kidney, and muscle of freshwater fish Oreochromis niloticus following acute and chronic exposures

Abstract

Freshwater fish Oreochromis niloticus were individually acutely exposed to different concentrations (0, 0.1, 0.5, 1.0, and 1.5 μg/mL) of Cd2+, Cr6+, and Ag+ for 96 h and 0.05 μg/mL concentration of the same metals for different periods (0, 5, 10, 20, and 30 days) chronically. Following each experimental protocol, Na+/K+-ATPase, Mg2+-ATPase, and Ca2+-ATPase activities were measured in the gill, kidney, and muscle of O. niloticus. In vitro experiments were also performed to determine the direct effects of metal ions (0, 0.1, 0.5, 1.0, and 1.5 μg/mL) on ATPases. Except Ag+, none of the metals caused fish mortality within 30 days. Silver killed all the fishes within 16 days. Metal exposures generally decreased Na+/K+-ATPase and Ca2+-ATPase activities in the tissues of O. niloticus, although there were some fluctuations in Mg2+-ATPase activity. Ag+ and Cd2+ were found to be more toxic to ATPase activities than Cr6+. It was also observed that metal efficiency was higher in the gill than in the other tissues. Results indicated that the response of ATPases varied depending on metals, exposure types, and tissues. Because ATPases are sensitive to metal toxicity, their activity can give valuable data about fish physiology. Therefore, they may be used as a sensitive biomarker in environmental monitoring in contaminated waters. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Sep 2011 | 3:47 pm CEST

Quercetin attenuates lambda cyhalothrin-induced reproductive toxicity in male rats

Abstract

The aim of this study was to evaluate the possible protective effects of Quercetin (Qe) against oxidative stress induced by λ cyhalothrin (LTC) in reproductive system. Thirty-two male rats were divided into four groups. First group was allocated as the control group. Second group was given a Qe alone while the third group received a LTC alone. Animals in the fourth group were given a Qe with LTC. Caudae epididymis was removed for sperm analysis. Lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and reduced glutathione (GSH) were determined in the testis. Additionally, the different histopathologic changes were observed in the testis of animals. LTC exposure significantly increased the abnormal morphology and LPO. On the contrary, sperm motility, viability and count, levels of GSH, and activities of SOD, CAT, GPx, and GST were significantly decreased compared to controls. Qe with LTC offset the decrease in functional sperm parameters, antioxidants enzymatic activities, and nonenzymatic antioxidant levels when compared with LTC-treated rats. Furthermore, LTC showed irregular seminiferous tubules containing only Sertoli cells and Qe with LTC caused regular seminiferous tubules showing spermatogenesis at level of spermatocytes. We conclude that LTC-induced oxidative stress and functional sperm parameters in male rats, and dietary of Qe attenuates the reproductive toxicity of LTC to restore the antioxidant system and sperm parameters in male rats. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 2 Sep 2011 | 10:09 am CEST

Classification of polycyclic aromatic hydrocarbons based on mutagenicity in lung tissue through DNA microarray

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants produced in the combustion of organic matter. Exposure to PAHs raises the risk of lung cancer and inflammatory and allergic disorders such as asthma. DNA microarray technologies have been applied to research on toxicogenomics in the recent years. To evaluate the mutagenicity of PAHs and constituents of environmental pollutants in lung tissue, including metabolic activation, human alveolar epithelial type II cells (A549) were treated with nonmutagenic PAH pyrene and with the mutagenic PAHs benzo-[a]-pyrene, 1-nitropyrene, or 1,8-dinitropyrene. Comparison of genome-wide microarray expression profiles between a nonmutagenic and a mutagenic PAH-treated group revealed that xenobiotic response genes such as CYP1B1 were commonly upregulated in two groups and that DNA damage induced genes, especially p53-downstream genes such as p21 (CDKN1A) were upregulated only in the mutagenic PAH-treated group. Pretreatment with cytochrome P450 inhibitor α-naphthoflavone or p53 inhibitor pifithrin-α inhibited the benzo-[a]-pyrene-induced p21 expression. These data suggest that when PAHs enter the cells, lung epithelium induces PAH metabolic activating enzymes, and then the DNA damages-recognition signal is converged with p53 downstream genes. This metabolic activation and DNA damage is induced in lung epithelium, and the mutagenicity of PAHs can be classified by DNA microarray expression profiles. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 2 Sep 2011 | 10:09 am CEST

Protective effects of vitamin E and selenium against dimethoate-induced cardiotoxicity in vivo: Biochemical and histological studies

Abstract

There is considerable interest in the study of free radical-mediated damage to biological systems due to pesticide exposure. However, there is a lack of consensus as to which determinations are best used to quantify future risks arising from xenobiotic exposure and natural antioxidant interventions. Our study investigated the potential ability of selenium and/or vitamin E, used as nutritional supplements, to alleviate cardiotoxicity induced by dimethoate. Female Wistar rats were exposed for 30 days either to dimethoate (0.2 g L−1 of drinking water), dimethoate+selenium (0.5 mg kg−1 of diet), dimethoate+vitamin E (100 mg kg−1 of diet), or dimethoate+selenium+vitamin E. The exposure of rats to dimethoate promoted oxidative stress with a rise in malondialdehyde, advanced protein oxidation, and protein carbonyl levels. An increase of glutathione peroxidase, superoxide dismutase, and catalase activities was also noted. A fall in acetylcholinesterase and Na+K+-ATPase activities, glutathione, nonprotein thiols, vitamins C and E levels was observed. Plasma levels of cholesterol, triglycerides, and low density lipoprotein-cholesterol increased and those of high density lipoprotein-cholesterol decreased. Coadministration of selenium or vitamin E to the diet of dimethoate-treated rats ameliorated the biochemical parameters cited above. The histopathological findings confirmed the biochemical results and the potential protective effects of selenium and vitamin E against cardiotoxicity induced by dimethoate. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 2 Sep 2011 | 10:08 am CEST

Estrogen-like response of perfluorooctyl iodide in male medaka (Oryzias latipes) based on hepatic vitellogenin induction

Abstract

Using the in vivo male medaka model, we investigated the estrogen-like response of perfluorooctyl iodide (PFOI) which is a potential source of perfluorinated carboxylic acids. Using real-time quantitative polymerase chain reaction, the expression levels of related estrogenic genes including estrogenic receptor α (ERα), ERβ, vitellogenin I (VTG I), and VTG II in the livers of male medaka exposed to PFOI were analyzed. The results showed that PFOI upregulated the expression levels of the tested genes in a dose-dependent manner. VTG protein levels increased in both dose- and time-dependent manners due to PFOI exposure. The results suggested that PFOI is a potential estrogenic compound. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 2 Sep 2011 | 10:08 am CEST

Gallic acid provokes DNA damage and suppresses DNA repair gene expression in human prostate cancer PC-3 cells

Abstract

Our earlier studies have demonstrated that gallic acid (GA) induced cytotoxic effects including induction of apoptosis and DNA damage and inhibited the cell migration and invasion in human cancer cells. However, GA-affected DNA damage and repair gene expressions in human prostate cancer cells are still unclear. In this study, we investigated whether or not GA induces DNA damage and inhibits DNA repair gene expression in a human prostate cancer cell line (PC-3). The results from flow cytometric assay indicated that GA decreased the percentage of viable PC-3 cells in a dose- and time-dependent manner. PC-3 cells after exposure to different doses (50, 100, and 200 μM) of GA and various periods of time (12, 24, and 48 h) led to a longer DNA migration smear (comet tail) occurred based on the single cell gel electrophoresis (comet assay). These observations indicated that GA-induced DNA damage in PC-3 cells, which also confirmed by 4,6-diamidino-2-phenylindole dihydrochloride staining and DNA agarose gel electrophoresis. Alternatively, results from real-time polymerase chain reaction assay also indicated that GA inhibited ataxia telangiectasia mutated, ataxia-telangiectasia and Rad3-related, O6-methylguanine-DNA methyltransferase, DNA-dependent serine/threonine protein kinase, and p53 mRNA expressions in PC-3 cells. Taken together, the present study showed that GA caused DNA damage and inhibited DNA repair genes as well as both effects may be the critical factors for GA-inhibited growth of PC-3 cells in vitro. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 2 Sep 2011 | 7:04 am CEST

Cadmium impairment of reproduction in the female wall lizard Podarcis sicula

Abstract

The exposure to environmental toxicants such cadmium (Cd) is an important research area in wildlife protection. In this study, the effect of Cd oral administration on the ovarian structure and function and on reproductive performance of the Italian wall lizard Podarcis sicula was studied. In vivo, adult female lizards were randomly assigned to three groups. Cd was given with food in single dose and in multiple doses 3 days/week for 4 weeks at dose of 1.0 μg/g body weight. Following euthanasia, the ovaries were removed and analyzed for morpho-functional changes. Results demonstrated that Cd increases prefollicular germ cells number; the evaluation of the number of follicles detects significantly higher number of atretic growing follicles, whereas primary follicles remain unchanged with respect to controls. After Cd treatments, follicles are deformed by the presence of large protrusions and a general dysregulation in the follicle organization is observed. The zona pellucida is also affected. Cd causes alteration in sugar metabolism and in metallothionein gene expression. Finally, Cd administration significantly reduces clutch size and dramatically increases embryo mortality. In conclusion, data here described show that Cd induces morpho-functional alterations in lizard follicles and indicates that these are responsible for a significant impairment of oogenesis. The effects of the dose are time independent, persisting essentially unchanged regardless of single or multiple administration, so it can be concluded that even occasional, sublethal Cd contamination may significantly impair reproductive performance in these animals. © 2011 Wiley Periodicals, Inc.Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 31 Aug 2011 | 1:45 pm CEST

The antioxidant effects of pumpkin seed oil on subacute aflatoxin poisoning in mice

Abstract

This study was aimed at the investigation of the antioxidant effect of pumpkin seed oil against the oxidative stress-inducing potential of aflatoxin. For this purpose, 48 male BALB/c mice were used. Four groups, each comprising 12 mice, were established. Group 1 was maintained as the control group. Group 2 was administered with pumpkin seed oil alone at a dose of 1.5 mL/kg.bw/day (∼1375mg/kg.bw/day). Group 3 received aflatoxin (82.45% AFB1, 10.65% AFB2, 4.13% AFG1, and 2.77% AFG2) alone at a dose of 625 μg/kg.bw/day. Finally, group 4 was given both 1.5 mL/kg.bw/day pumpkin seed oil and 625 μg/kg.bw/day aflatoxin. All administrations were oral, performed with the aid of a gastric tube and continued for a period of 21 days. At the end of day 21, the liver, lungs, kidneys, brain, heart, and spleen of the animals were excised, and the extirpated tissues were homogenized appropriately. Malondialdehyde (MDA) levels and catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities were determined in tissue homogenates. In conclusion, it was determined that aflatoxin exhibited adverse effects on most of the oxidative stress markers. The administration of pumpkin seed oil diminished aflatoxin-induced adverse effects. In other words, the values of the group, which was administered with both aflatoxin and pumpkin seed oil, were observed to have drawn closer to the values of the control group. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 31 Aug 2011 | 1:43 pm CEST

Arsenic methylation metabolism and liver injury of acute promyelocytic leukemia patients undergoing arsenic trioxide treatment

Abstract

Although arsenic is effective in the treatment of acute promyelocytic leukemia (APL), as a well-known environmental toxicant, the side effects of arsenic treatment and arsenic methylation metabolism of the patients are rarely reported. In this manuscript, we investigated 23 APL patients treated with 10 mg arsenic trioxide daily, detected the arsenic metabolites in urine samples collected on the 0, 10th, and 20th day of arsenic treatment. At the same time, liver function and blood routine examination were also investigated in these APL patients. We found that, urinary monomethylated arsenic proportion (MMA%) increased, but dimethylated arsenic proportion (DMA%), the first methylation ratio (FMR) and the secondary methylation ratio (SMR) decreased with consecutive administration of arsenic trioxide. After adjustment for age impact, no statistical difference was observed in urinary arsenic concentrations and arsenic methylation capacity between male and female at the same treatment time point. During arsenic trioxide treatment of APL, transient elevation of serum aminotransferases was found in the blood samples, which indicated that liver injury occurred and probably reversible. Leukocytosis developed in 5 of the 23 patients with the administration of arsenic trioxide. No statistical difference was observed in the other blood routine examination parameters. These results demonstrated that the capacity of arsenic methylation decreased and transient liver injury occurred during arsenic trioxide treatment of APL, which indicated that the side effects of clinical arsenic treatment can not be ignored. © Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 31 Aug 2011 | 12:05 pm CEST

Protective effect of lycopene on oxidative stress and antioxidant status in Cyprinus carpio during cypermethrin exposure

Abstract

The aim of this study was to investigate the ameliorative properties of lycopene against the toxic effects of cypermethrin (CYP) by examining oxidative damage markers such as lipid peroxidation and the antioxidant defense system components in carp (Cyprinus carpio). The fish were divided into seven groups of 10 fish each and received the following treatments: group 1, no treatment; group 2, orally administered corn oil; group 3, oral lycopene (10 mg/kg body weight); group 4, exposure to 0.202 μg/L CYP; group 5, exposure to 0.202 μg/L CYP plus oral administration of 10 mg/kg lycopene; group 6, exposure to 0.404 μg/L CYP; and group 7, exposure to 0.404 μg/L CYP plus oral administration of 10 mg/kg lycopene. Treatment was continued for 28 days, and at the end of this period, blood and tissue (liver, kidney, and gill) samples were collected. Levels of malondialdehyde (MDA) and reduced glutathione (GSH) as well as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were determined in blood and tissues for measurement of oxidant-antioxidant status. MDA level, as an index of lipid peroxidation, increased in blood and tissues. Antioxidant enzyme activities in blood and tissues were modified in CYP groups compared with controls. Administration of lycopene ameliorated these parameters. The present results suggest that administration of lycopene might alleviate CYP-induced oxidative stress. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 25 Aug 2011 | 7:45 am CEST

Indium chloride-induced micronuclei via reactive oxygen species in Chinese hamster lung fibroblast V79 cells

Abstract

We study the cytotoxicity of indium chloride (InCl3) in Chinese hamster lung fibroblasts, the V79 cells, using MTT assay. The results showed that InCl3 did not induce significant cytotoxicity at various concentrations tested. In addition, the frequency of micronuclei (MN) was assayed to evaluate the genotoxic effects of InCl3 in V79 cells. InCl3 at concentrations ranged 0.1–1 μM significantly increased MN frequency in a concentration-dependent manner. Both catalase and superoxide dismutase at concentrations of 75 and 150 μg/mL significantly inhibited InCl3-induced MN. Similarly, Germanium oxide (GeO2) and dimercaprol expressed antigenotoxic effects. From these findings, it is concluded that InCl3 is a potent genotoxic chemical, which may be mediated partly by inducing oxidative stress. The significance of this study shows that the workers in the semiconductor factories should be cautious in exposing to the hazardous genotoxic InCl3. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 24 Aug 2011 | 11:51 am CEST

Glucose and lipid homeostasis in adult rat is impaired by early-life exposure to perfluorooctane sulfonate

Abstract

Perfluorooctane sulfonate (PFOS), which belongs to the degradation product of many perfluorinated compounds, is on the list of persistent organic pollutants (POPs) and is currently detected in both wildlife and humans. The consequence of gestational and lactational exposure to PFOS on prediabetes effect in offspring was investigated in rats in the present study. Maternal rats were treated with vehicle, 0.5 mg/kg/day or 1.5 mg/kg/day PFOS respectively from gestation day 0 to postnatal day 21. The glucose and lipid metabolism effects were investigated on the offspring in adulthood. The gestational and lactational exposure to PFOS led to low body weight from birth to weaning, and evoked signs of a prediabetic state, with elevated fasting serum insulin and leptin level, impaired glucose tolerance, though the fasting serum glucose and glycosylated serum protein level were normal. Abnormal lipid homeostasis was also observed by the phenomenon of hepatic steatosis and increased gonadal fat pad weight. However, the circulating serum level of fasting triglyceride and cholesterol level were no different from controls. Our results suggested that developmental exposure to PFOS may contribute to glucose and lipid metabolic disorder in adulthood. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 24 Aug 2011 | 11:50 am CEST

Prenatal exposure to permethrin influences vascular development of fetal brain and adult behavior in mice offspring

Abstract

Pyrethroids are one of the most widely used classes of insecticides and show neurotoxic effects that induce oxidative stress in the neonatal rat brain. However, little is still known about effects of prenatal exposure to permethrin on vascular development in fetal brain, central nervous system development, and adult offspring behaviors. In this study, the effects of prenatal exposure to permethrin on the development of cerebral arteries in fetal brains, neurotransmitter in neonatal brains, and locomotor activities in offspring mice were investigated. Permethrin (0, 2, 10, 50, and 75 mg/kg) was orally administered to pregnant females once on gestation day 10.5. The brains of permethrin-treated fetuses showed altered vascular formation involving shortened lengths of vessels, an increased number of small branches, and, in some cases, insufficient fusion of the anterior communicating arteries in the area of circle of Willis. The prenatal exposure to permethrin altered neocortical and hippocampus thickness in the mid brain and significantly increased norepinephrine and dopamine levels at postnatal day 7 mice. For spontaneous behavior, the standing ability test using a viewing jar and open-field tests showed significant decrease of the standing ability and locomotor activity in male mice at 8 or 12 weeks of age, respectively. The results suggest that prenatal exposure to permethrin may affect insufficient development of the brain through alterations of vascular development. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 24 Aug 2011 | 11:01 am CEST

Safrole suppresses murine myelomonocytic leukemia WEHI-3 cells in vivo, and stimulates macrophage phagocytosis and natural killer cell cytotoxicity in leukemic mice

Abstract

Many anticancer drugs are obtained from phytochemicals and natural products. However, some phytochemicals have mutagenic effects. Safrole, a component of Piper betle inflorescence, has been reported to be a carcinogen. We have previously reported that safrole induced apoptosis in human oral cancer cells in vitro and inhibited the human oral tumor xenograft growth in vivo. Until now, there is no information addressing if safrole promotes immune responses in vivo. To evaluate whether safrole modulated immune function, BALB/c mice were intraperitoneally injected with murine myelomonocytic WEHI-3 leukemia cells to establish leukemia and then were treated with or without safrole at 4 and 16 mg/kg. Animals were sacrificed after 2 weeks post-treatment with safrole for examining the immune cell populations, phagocytosis of macrophages and the natural killer (NK) cells' cytotoxicity. Results indicated that safrole increased the body weight, and decreased the weights of spleen and liver in leukemic mice. Furthermore, safrole promoted the activities of macrophages phagocytosis and NK cells' cytotoxicity in leukemic mice when compared with untreated leukemic mice. After determining the cell marker population, we found that safrole promoted the levels of CD3 (T cells), CD19 (B cells) and Mac-3 (macrophages), but it did not affect CD11b (monocytes) in leukemic mice. In conclusion, safrole altered the immune modulation and inhibited the leukemia WEHI-3 cells in vivo. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 24 Aug 2011 | 11:00 am CEST

In vivoexamination of the genotoxicity of the urban air and surface soil pollutant, 3,6-dinitrobenzo[e]pyrene, with intraperitoneal and intratracheal administration

Abstract

3,6-Dinitrobenzo[e]pyrene (3,6-DNBeP) was identified as a new potent mutagen toward Salmonella strains in surface soil and airborne particles. Because data of in vivo examination of the genotoxicity of 3,6-DNBeP are limited, micronucleus test was performed in peripheral blood and bone marrow, and comet assay in the lungs of mice treated with 3,6-DNBeP. In male ICR mice intraperitoneally (i.p.) injected with 3,6-DNBeP, the frequency of micronuclated polychromatic erythrocytes (MNPCEs) was increased in the peripheral blood and bone marrow after 24 h in a dose-dependent manner. Compared to controls, the highest dose of 3,6-DNBeP (40 mg/kg B.W.) induced 7.3- and 8.7-fold increases of MNPCE frequency in the peripheral blood and bone marrow, respectively. Furthermore, when 3,6-DNBeP was intratracheally (i.t.) instilled to male ICR mice, 3,6-DNBeP at the highest dose of 0.1 mg/kg body exhibited 3.1-fold increase of DNA tail moment in the lungs at 3 h after the instillation compared to controls. The values of DNA tail moment at 9 and 24 h after the instillation were increased up to 3.5 and 4.2-fold, respectively. These data indicate that 3,6-DNBeP is genotoxic to mammalians in in vivo and suggest that 3,6-DNBeP may be a carcinogenic compound present in the human environment. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 24 Aug 2011 | 10:59 am CEST

Effects of perinatal exposure to low doses of tributyltin chloride on pregnancy outcome and postnatal development in mouse offspring

Abstract

Tributyltin (TBT), an endocrine-disrupting chemical, is well known to induce imposex in female gastropods. In this study, we assessed the effects of low doses of tributyltin chloride (TBTCl) on dams and their offspring. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. There were no TBT treatment-related deaths or clinical signs of toxicity for dams, and no treatment-related effects on body weight, litter sizes, gestational length of dams, and sex ratio, lactational body weight, postnatal survival, age at eruption of incisors, and eye opening of pups. However, at 100 μg/kg, TBTCl retarded the testes descent of male offspring. Behavioral tests showed a significant delay in cliff-drop aversion response in offspring of 10 and 100 μg/kg groups, but no significant difference in the righting reflex between control and TBT-exposed offspring was detectable. These results indicate that neurobehavioral toxicity seems to be one sensitive indicator to assess the risk of low doses of TBT. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 24 Aug 2011 | 10:59 am CEST

Nerium indicum, a botanical pesticide affects ultimobranchial gland of the catfish Heteropneustes fossilis

Abstract

Heteropneustes fossilis were subjected to 11.27 mg L−1 (80% of 96 h LC50) and 2.81 mg L−1 (20% of 96 h LC50) of Nerium indicum leaf extract for short-term and long-term, respectively. After sacrificing the fish, blood was collected on 24, 48, 72, and 96 h in short-term and after 7, 14, 21, and 28 days in long-term experiment and analyzed for plasma calcium levels. Also, ultimobranchial glands (UBG) were fixed on these intervals. Serum calcium levels of H. fossilis exhibited a decline after 48 h following exposure to Nerium indicum leaf extract. This decrease continued till the end of the experiment (96 h). Ultimobranchial cells exhibited a decrease in the cytoplasmic staining response after 72 h following the treatment. The nuclear volumes of these cells were slightly decreased. These changes were exaggerated after 96 h following the treatment. Chronically exposed fish exhibited a decline in serum calcium levels of H. fossilis on day 14. The level progressively declined till the end of the experiment. Up to day 14 following the treatment there was no change in the histological structure of UBG. A decrease in the nuclear volume of ultimobranchial cells was noticed on day 21. Moreover, the cytoplasm of these cells displayed weakstaining response. The nuclear volume of these cells recorded a further decrease following 28-day treatment. Also there was noticed vacuolization and degeneration at certain places. To the best of our knowledge, the effects of any botanical pesticides on fish UBG have not been reported yet. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 24 Aug 2011 | 10:58 am CEST

Is cell death induced by nematocysts extract of medusa Pelagia noctiluca related to oxidative stress?

Abstract

Pelagia noctiluca, a jellyfish widely distributed in the Mediterranean waters, especially in coastal areas of Tunisia, has garnered attention because of its stinging capacity and the resulting public health hazard. Crude extracts of P. noctiluca nematocysts have been tested for their cytotoxicity on Vero cells. Our results clearly showed that nematocysts induced cell mortality in a dose- and time-dependent manner. A cytoprotective effect against cell mortality was obtained when Vero cells were treated with Vitamin E. This process was further confirmed by the generation of reactive oxygen species (ROS) and the induction of Hsp 70 and 27 protein expressions. Thus, our findings suggested that oxidative stress is involved in the toxicity of pelagia nematocysts and may therefore constitute the major mechanism of this medusa nematocysts toxicity. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 2 Aug 2011 | 2:33 am CEST

Sodium arsenite induced reactive oxygen species generation, nuclear factor (erythroid-2 related) factor 2 activation, heme oxygenase-1 expression, and glutathione elevation in Chang human hepatocytes

Abstract

Liver is one of the major target organs of arsenic toxicity and carcinogenesis. Nuclear factor (erythroid-2 related) factor 2 (Nrf2) is a redox-sensitive transcription factor, regulating critically cellular defense responses against the toxic metallic arsenic in many cell types and tissues. This study was conducted to evaluate the hepato-cellular Nrf2 and Nrf2-regulated antioxidant reactions of sodium arsenite exposure in Chang human hepatocytes. Nrf2 and heme oxygenase-1 (HO-1) protein levels were detected by Western blot, and Nrf2-regulated HO-1 mRNA expressions were determined using semiquantitative RT-PCR by 0∼50 μmol/L of sodium arsenite exposure for 2, 6, 12, and 24 h. We also observed the changes of intracellular reactive oxygen species (ROS) and total cellular glutathione (GSH) by flow cytometry and spectrophotometry, respectively. Our results showed that intracellular ROS were both dose- and time-dependent induced by inorganic arsenic; Cellular Nrf2 protein levels increased rapidly after 2 h of exposure, elevated significantly at 6 h, and reached the maximum at 12 h. The endogenous Nrf2-regulated downstream HO-1 mRNA and protein were also induced dramatically and lasted for as long as 24 h. In addition, intracellular GSH levels elevated in consistent with Nrf2 activation. Our findings here suggest that inorganic arsenic alters cellular redox balance in hepatocytes to trigger Nrf2-regulated antioxidant responses promptly, which may represent an adaptive cell defense mechanism against inorganic arsenic induced liver injuries and hepatoxicity. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 2 Aug 2011 | 2:33 am CEST

Induction of apoptosis by curcumin in murine myelomonocytic leukemia WEHI-3 cells is mediated via endoplasmic reticulum stress and mitochondria-dependent pathways

Abstract

Curcumin, derived from the food flavoring spice turmeric (Curcuma longa), has been shown to exhibit anticancer activities and induce apoptosis in many types of cancer cell lines. In our previous study, curcumin was able to inhibit murine myelomonocytic leukemia WEHI-3 cells in vivo. However, there is no report addressing the cytotoxic responses and the mechanisms underlying curcumin-induced apoptotic cell death in WEHI-3 cells. Therefore, we hypothesized that that curcumin affected WEHI-3 cells and triggered cell death through apoptotic signaling pathways. The effects of curcumin on WEHI-3 cells were investigated by using flow cytometric analysis, comet assay, confocal laser microscopy and Western blotting. In this study, we found that curcumin induced apoptosis in WEHI-3 cells in a dose-dependent (5–20 μM) manner. Interestingly, curcumin enhanced the level of the antiapoptotic protein Bcl-2 which might show that curcumin-induced apoptosis is done through the ER stress signaling pathways based on the increase of CIEBP homologous protein (CHOP), activating transcription factor 6 (ATF-6), inositol-requiring enzyme 1 (IRE1), and caspase-12 in WEHI-3 cells. Moreover, curcumin increased the reactive oxygen species (ROS) production and cytosolic Ca2+ release, and induced DNA damage, but decreased the level of mitochondrial membrane potential (ΔΨm) in WEHI-3 cells. In conclusion, curcumin-induced apoptosis occurs through the ROS-affected, mitochondria-mediated and ER stress-dependent pathways. The evaluation of curcumin as a potential therapeutic agent for treatment of leukemia seems warranted. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 26 Jul 2011 | 8:59 pm CEST

Maternal exposure to the mixture of organophosphorus pesticides induces reproductive dysfunction in the offspring

Abstract

Organophosphorus pesticide residues are found in many food samples due to increasing use of multiple organophosphorus pesticides (OPs) in agriculture. Toxicity of individual organophosphorus has been well-studied in previous epidemiological and laboratory investigations. This study focused on reproductive toxicity of perinatal exposure to the mixture of organophosphorus pesticides (MOPs). The MOPs consists of three most commonly used pesticides, i.e., Dichlorovos, Dimethoate, and Malathion which individually does not cause significant effects on the reproductive system at the similar concentration levels based on previous studies. Using the Sprague-Dawley rats, we established a perinatal exposure model by oral gavage and observed significant endometrial hyperplasia and thickened uterine walls in the F0 rats after administration of high doses of the MOPs. We further monitored several key developmental and behavioral indices in the F1 generation after maternal exposure to the MOPs, and observed significantly delayed physical development and weakened mental development. Moreover, we found increased weights of the reproductive organs (the uterus and the testis) and abnormal levels of key sex hormones (progestin and testosterone) in the MOPs groups. It is more important that we observed a significantly lower pregnancy rate and live birth rate in the high-dose MOPs group. These results indicate that the MOPs may be more detrimental to the maternal endometria and the reproductive functions in the offspring than individual organophosphorus. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 26 Jul 2011 | 8:00 pm CEST

Lanthanum chloride promotes mitochondrial apoptotic pathway in primary cultured rat astrocytes

Abstract

Population surveys and animal experiments have shown that rare earth elements (REEs) cause neurological defects. However, the detailed mechanisms underlying these effects are still unclear. Given that lanthanum is commonly used for investigating into REEs-induced neurological defects, this study chose lanthanum chloride (LaCl3) to show that LaCl3 promotes mitochondrial apoptotic pathway in primary cultured rat astrocytes by regulating expression of Bcl-2 family proteins. The main findings of this study are (1) LaCl3 treatment (0.25, 0.5, and 1.0 mM for 12–48 h) induced the astrocytes damages with a concentration-dependent manner, which were confirmed with methyl thiazolyl tetrazolium and lactate dehydrogenase release assays, and morphological examination. (2) A 24 h treatment of LaCl3 concentration-dependently decreased mitochondrial membrane potential, increased cytochrome c release from mitochondria into cytosol, elevated caspase 9 and 3 expression, and promoted astrocyte apoptosis. (3) LaCl3 treatment increased the ratio of pro-apoptotic Bax and antiapoptotic Bcl-2 proteins, which in turn broke the balance among pro-apoptotic and antiapoptotic Bcl-2 family proteins, leading to astrocyte apoptosis. Our results indicate that LaCl3 alters Bcl-2 family protein expressions, which in turn promote mitochondrial apoptotic pathway, and thus astrocytic damage. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 26 Jul 2011 | 8:00 pm CEST

Resveratrol protects against methylglyoxal-induced apoptosis and disruption of embryonic development in mouse blastocysts

Abstract

Methylglyoxal (MG) is a glucose metabolite. Diabetic patients have increased serum levels of MG, and MG is also implicated in tissue injury during embryonic development. In the present work, we show that MG induces apoptosis in the inner cell mass of mouse blastocysts and inhibits cell proliferation. Both effects are suppressed by resveratrol, a grape-derived phytoalexin with known antioxidant and anti-inflammatory properties. MG-treated blastocysts displayed lower levels of implantation (compared to controls) when plated on culture dishes in vitro and a reduced ability to proceed to later stages of embryonic development. Pretreatment with resveratrol prevented MG-induced disruption of embryonic development, both in vitro and in vivo. Further investigation of these processes revealed that MG directly promotes reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential (MMP), and activation of caspase-3, whereas resveratrol effectively blocks MG-induced ROS production and the accompanying apoptotic biochemical changes. Our results collectively imply that MG triggers the mitochondrion-dependent apoptotic pathway via ROS generation, and the antioxidant activity of resveratrol prevents MG-induced toxicity. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 26 Jul 2011 | 8:00 pm CEST

Evaluation of factors associated with cadmium exposure and kidney function in the general population

Abstract

Cadmium (Cd) is a nonessential toxic metal which is widely distributed in the environment. The general population is exposed to low levels of Cd and the kidney is the organ most sensitive to Cd toxicity. This study was performed to simultaneously evaluate Cd exposure, kidney function, and oxidative stress biomarkers in the general population. A total of 643 adults were interviewed to document demographic characteristics, lifestyles, past-medical history, and diet during the last 24 h. We estimated daily Cd intake based on the diet of study subjects who had not been exposed to Cd occupationally. Whole blood and urine samples were collected and analyzed to determine Cd concentrations and kidney function indices (β2-microglobulin [β2-MG], N-acetyl-β-D-glucosaminidase [NAG], metallothionein [MT]). The oxidative stress index (malondialdehyde [MDA]) was determined from the urine. The daily Cd intake from diet was established as 7.07 μg/day. The mean concentration of Cd measured in the blood was 1.22 μg/L and urine was 0.95 μg/g creatinine. The concentrations of Cd in blood and urine were higher in females than in males. The blood levels of Cd were affected by sex, age, and smoking, and urine Cd was influenced by sex, age, and blood Cd. The urine Cd was positively correlated with MT, NAG activity, and MDA in females, but with NAG only in males. The blood Cd was associated with MT in males. Increased NAG activity was observed when Cd in urine reached 1.0 μg Cd/g creatinine and was also affected by age, hypertension, and diabetes mellitus. Urinary MT only responded to Cd in urine or blood. In summary, exposure to Cd in the general population was influenced by various factors including sex, age, and smoking habits. Such exposure might eventually cause tubular damage in the kidneys through the oxidative stress mechanism, and females might be more susceptible than males to Cd exposure under the environment. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011

Quelle: Environmental Toxicology | 22 Jul 2011 | 4:51 pm CEST

Evaluation of DNA damage and cytotoxicity induced by three commonly used organophosphate pesticides individually and in mixture, in rat tissues

Abstract

Organophosphate pesticides are among the most widely used synthetic chemicals for controlling a wide variety of pests. Chlorpyrifos (CPF), methyl parathion (MPT), and malathion (MLT) are among the most extensively used organophosphate (OP) pesticides. The main target of action of OP compounds is the central and peripheral nervous system, although it has also been postulated that these compounds in both acute and chronic intoxication, disturb the redox processes and thus induce oxidative stress. The excessive generation of reactive oxygen species (ROS) causes damage to all vital macromolecules including lipids, proteins, and DNA. This study was aimed to investigate the genotoxicity and cytotoxicity of CPF, MPT, and MLT when given singly or in combination. The DNA damage was measured by alkaline single-cell gel electrophoresis or comet assay and expressed as DNA damage index. The results showed that both acute and chronic exposure with CPF, MPT, and MLT, caused significantly marked DNA damage in rat tissues namely, liver, brain, kidney, and spleen, when measured 24 hour posttreatment. It was also observed that MPT caused highest level of DNA damage and brain was maximally affected by these OP compounds. When these pesticides were given in mixture, the damage was not the sum of damage caused by individual pesticide, confirming that these pesticides do not potentiate the toxicity of each other. When the DNA damage was measured 48 and 72 hour posttreatment, the damage was partially repaired. Pesticide exposure also caused histopathological changes in rat tissues. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011

Quelle: Environmental Toxicology | 22 Jul 2011 | 4:51 pm CEST

Cytogenetic effects of commercial formulations of deltamethrin and/or thiacloprid on Wistar rat bone marrow cells

Abstract

Deltamethrin (DEL) and thiacloprid (THIA) are two insecticides that are widely used in agriculture either separately or in combination. Studies on genotoxicity and cytotoxicity of TIA and the mixture of DEL and THIA insecticides have not been reported so far. Therefore, we investigated the cytotoxic and genotoxic effects of commercial formulations DEL and/or THIA in rat bone marrow cells, using mitotic index (MI), micronucleus (MN) and chromosome aberrations (CA) assay. In vivo cytokinesis-block micronucleus (CBMN) assay using cytochalasin-B in bone marrow cells was performed for the first time in this study. Rats were orally gavaged with a single dose of DEL (15 mg/kg), THIA (112.5 mg/kg) or DEL + THIA (15 + 112.5 mg/kg) for 24 h (acute treatments), or DEL (3 mg/kg/day), THIA (22.5 mg/kg/day) or DEL + THIA (3 + 22.5 mg/kg/day) for 30 days (subacute treatments). A corn oil vehicle control group and cyclophosphamide (50 mg/kg) positive control group were also included. All DEL and/or THIA treatments significantly decreased MI and binucleated (BN) cell numbers, and significantly increased CA, as compared to the vehicle control group. The results of CBMN assay indicated that the combination of DEL and THIA for both treatment times and the 30-day treatment with THIA alone caused a significant increase in micronucleus formation in BN cells. The present findings indicated the combined exposure of DEL and THIA showed genotoxic and cytotoxic effects more than those of individual exposure of DEL or THIA in rat bone marrow cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 22 Jul 2011 | 4:51 pm CEST

Induction of reactive oxygen species in Chlamydomonas reinhardtii in response to contrasting trace metal exposures

Abstract

The toxicity of metals to organisms is, in-part, related to the formation of reactive oxygen species (ROS) in cells and subsequent oxidative stress. ROS are by-products of normal respiration and photosynthesis processes in organisms, but environmental factors, like metal exposure, can stimulate excess production. Metals involved in several different mechanisms such as Haber-Weiss cycling and Fenton-type reactions can produce ROS. Some metals, such as Cd, may contribute to oxidative stress indirectly by depleting cellular antioxidants. We investigated the measurement of ROS as a sensitive biomarker of metal toxicity (that could possibly be implemented in a biotic ligand model for algae) and we compared ROS induction in response to several contrasting transition metals (Cu, V, Ni, Zn, and Cd). We also compared the ROS response to glutathione and growth toxicity endpoints measured in a previous study. The cell-permeable dye, 2′7′dichlorodihydrofluorescein diacetate, was used as a probe to detect formation of ROS in Chlamydomonas reinhardtii cells. Metal-exposed cells were incubated with the fluorescent dye in a 96-well plate and monitored over 5.5 h. A dose-response of ROS formation was observed with Cu exposure in the range of 20–500 nM. Cu produced more ROS compared with either Zn or Cd (both nonredox active metals). The redox-active metal V produced increased ROS with increased concentration. The measurement of ROS may be a useful indicator of Cu toxicity, but the signal to noise ratio was better for the glutathione endpoint assay. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 22 Jul 2011 | 4:50 pm CEST

cDNA microarray analysis of the gene expression of murine leukemia RAW 264.7 cells after exposure to propofol

Abstract

Propofol (2,6-diisopropylphenol) is the most extensively used general anesthetic-sedative agent and it is employed in clinical patients. It has been shown that propofol exhibits anticancer activities. However, there is no available information to address propofol-induced cytotoxic effects and affected gene expressions on murine leukemia cells. Therefore, we investigated the effects of propofol on the levels of protein and gene expression, which are associated with apoptotic death in mouse leukemia RAW 264.7 cells in vitro. Results indicated that propofol induced cell morphological changes, cytotoxicity, and induction of apoptosis in RAW 264.7 cells in vitro. Western blot analysis demonstrated that propofol promoted Fas, cytochrome c, caspase-9 and −3 active form and Bax levels, but inhibited Bcl-xl protein level which led to cell apoptosis. Furthermore, cDNA microarray assay indicated that propofol significantly enhanced 5 gene expressions (Gm4884; Gm10883; Lce1c; Lrg1; and LOC100045878) and significantly suppressed 26 gene expressions (Gm10679; Zfp617; LOC621831; LOC621831; Gm5929; Snord116; Gm3994; LOC380994; Gm5592; LOC380994; Gm4638; LOC280487; Gm4638; Tex24; A530064D06Rik; BC094916; EG668725; Gm189; Hist2h3c2; Gm8020; Snord115; Gm3079; Olfr198; Tdh; Snord115; and Olfr1249). Based on these observations, propofol-altered apoptosis-related proteins might result from induction of apoptotic gene expression and inhibition of cell growth gene expression, which finally led to apoptosis in a mouse leukemia cell line (RAW 264.7) in vitro. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 22 Jul 2011 | 4:50 pm CEST

Relationship between intracellular Ca2+ and ROS during fluoride-induced injury in SH-SY5Y cells

Abstract

The mechanisms underlying the neurotoxicology of endemic fluorosis still remain obscure. To explore lactate dehydrogenase (LDH) leakage, intracellular Ca2+ concentration ([Ca2+]i) and reactive oxygen species (ROS) production induced by fluoride, human neuroblastoma (SH-SY5Y) cells were incubated with sodium fluoride (NaF, 20, 40, 80 mg/L) for 24 h, with 40 mg/L NaF for 3, 6, 12, 18, 24 h, and N-acetyl-L-cysteine (NAC), ethyleneglycol-bis-(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA), 1,2-bis(O-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetra(acetoxymethyl) ester (BAPTA-AM) alone or combined with fluoride (40 mg/L) respectively for 12 h in vitro. The results showed that the LDH levels in the 40 and 80 mg/L fluoride-treated groups were significantly higher than that of the control group (in the test level of 0.05, the difference were statistical significance). [Ca2+]i and ROS reached a peak at 3 h and 12 h respectively after exposure to 40 mg/L fluoride. Fluoride coincubated with NAC (antioxidant) dramatically decreased ROS and LDH levels compared with the fluoride only group (in the test level of 0.05, the difference were statistical significance). However, fluoride-induced increase in [Ca2+]i was not affected by NAC. BAPTA-AM (intracellular calcium chelator) markedly lowered fluoride-induced increase of [Ca2+]i, ROS and LDH levels while EGTA (extracellular calcium chelator) have no effects on them. These results indicate that fluoride-related Ca2+ release from the site of intracellular calcium storage causes the elevation of ROS contributing to the cytotoxicity in SH-SY5Y cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 22 Jul 2011 | 4:50 pm CEST

Zebrafish neurotoxicity from aphantoxins—cyanobacterial paralytic shellfish poisons (PSPs) from Aphanizomenon flos-aquae DC-1

Abstract

Aphanizomenon flos-aquae (A. flos-aquae), a cyanobacterium frequently encountered in water blooms worldwide, is source of neurotoxins known as PSPs or aphantoxins that present a major threat to the environment and to human health. Although the molecular mechanism of PSP action is well known, many unresolved questions remain concerning its mechanisms of toxicity. Aphantoxins purified from a natural isolate of A. flos-aquae DC-1 were analyzed by high-performance liquid chromatography (HPLC), the major component toxins were the gonyautoxins1 and 5 (GTX1 and GTX5, 34.04% and 21.28%, respectively) and the neosaxitoxin (neoSTX, 12.77%). The LD50 of the aphantoxin preparation was determined to be 11.33 μg/kg (7.75 μg saxitoxin equivalents (STXeq) per kg) following intraperitoneal injection of zebrafish (Danio rerio). To address the neurotoxicology of the aphantoxin preparation, zebrafish were injected with low and high sublethal doses of A. flos-aquae DC-1 toxins 7.73 and 9.28 μg /kg (5.3 and 6.4 μg STXeq/kg, respectively) and brain tissues were analyzed by electron microscopy and RT-PCR at different timepoints postinjection. Low-dose aphantoxin exposure was associated with chromatin condensation, cell-membrane blebbing, and the appearance of apoptotic bodies. High-dose exposure was associated with cytoplasmic vacuolization, mitochondrial swelling, and expansion of the endoplasmic reticulum. At early timepoints (3 h) many cells exhibited characteristic features of both apoptosis and necrosis. At later timepoints apoptosis appeared to predominate in the low-dose group, whereas necrosis predominated in the high-dose group. RT-PCR revealed that mRNA levels of the apoptosis-related genes encoding p53, Bax, caspase-3, and c-Jun were upregulated after aphantoxin exposure, but there was no evidence of DNA laddering; apoptosis could take place by pathways independent of DNA fragmentation. These results demonstrate that aphantoxin exposure can cause cell death in zebrafish brain tissue, with low doses inducing apoptosis and higher doses inducing necrosis. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 25 Jun 2011 | 12:22 am CEST

Bioaccumulation of algal toxins and changes in physiological parameters in Mediterranean mussels from the North Adriatic Sea (Italy)

Abstract

The Northwestern Adriatic Sea is a commercially important area in aquaculture, accounting for about 90% of the Italian mussel production, and it was subjected to recurring cases of mussel farm closures due to toxic algae poisoning. A spatial and temporal survey of four sites along the North Adriatic Sea coasts of Emilia Romagna (Italy) was undertaken to study the possible impairments of physiological parameters in Mytilus galloprovincialis naturally exposed to algal toxins. The sites were selected as part of the monitoring network for the assessment of algal toxins bioaccumulation by the competent Authority. Samples positive to paralytic shellfish toxins and to lipophilic toxins were detected through the mouse bioassay. Lipophilic toxins were assessed by HPLC. Decreasing yessotoxins (YTX) levels were observed in mussels from June to December, while homo-YTX contents increased concomitantly. Lysosome membrane stability (LMS), glutathione S-transferase and catalase activities, and multixenobiotic resistance (MXR)-related gene expressions were assessed as parameters related to the mussel health status and widely utilized in environmental biomonitoring. Levels of cAMP were also measured, as possibly involved in the algal toxin mechanisms of action. Low LMS values were observed in hemocytes from mussels positive to the mouse bioassay. MXR-related gene expressions were greatly inhibited in mussels positive to the mouse bioassay. Clear correlations were established between increasing homo-YTX contents (and decreasing YTX) and increasing cAMP levels in the tissues. Similarly, significant correlations were established between the increase of homo-YTX and cAMP levels, and the expressions of three MXR-related genes at submaximal toxin concentrations. In conclusion, YTXs may affect mussel physiological parameters, including hemocyte functionality, gene expression and cell signaling. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 21 Jun 2011 | 3:46 pm CEST

Diallyl sulfide, diallyl disulfide, and diallyl trisulfide inhibit migration and invasion in human colon cancer colo 205 cells through the inhibition of matrix metalloproteinase-2, -7, and -9 expressions

Abstract

Diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS) are major organosulfur compounds exiting in garlic (Allium sativum). These compounds are reported to exhibit various pharmacological properties such as antibacteria, antiangiogenesis, anticancer, and anticoagulation, and they also induce cytotoxicity and induction of apoptosis in human cancer cells. Although these compounds show wide spectrum of biological activities, there are no reports to show that DAS, DADS, and DATS affected migration and invasion of human colon cancer cells, and their exact molecular mechanisms are not well investigated. Therefore, the purpose of this study was to determine whether DAS, DADS, and DATS affected the invasion and migration abilities of colo 205 human colon cancer cells. The results indicate that DAS, DADS, and DATS at 10 and 25 μM inhibited the migration and invasion of colo 205 cells in the order of DATS < DADS < DAS. DATS is the highest for inhibition of migration and invasion of colo 205 cells. DAS, DADS, and DATS induce downregulation expression of PI3K, Ras, MEKK3, MKK7, ERK1/2, JNK1/2, and p38 and then lead to the inhibition of MMP-2, -7, and -9. DAS, DADS, and DATS inhibited NF-κB and COX-2 for leading to the inhibition of cell proliferation. Taken together, these results demonstrated that application of DAS, DADS, and DATS might serve as potential antimetastatic drugs. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 21 Jun 2011 | 3:46 pm CEST

Life-cycle exposure to the estrogenic mycotoxin zearalenone affects zebrafish (Danio rerio) development and reproduction

Abstract

Zearalenone (ZON) is one of the worldwide most common mycotoxin and exhibits estrogenic activity in the range of natural steroid estrogens. The occurrence of ZON has been reported in soil, drainage water, wastewater effluents, and rivers, but its ecotoxicological effects on fish have hardly been investigated. The consequences of continuous long-term ZON exposure, including a subsequent depuration period, as well as transgenerational effects of F0 short-term exposure on F1 generation were investigated. Effects on growth, reproduction activity, physiology, and morphology of zebrafish (Danio rerio) were examined in a 182 day live-cycle experiment. Life-long exposure to ZON for 140 days increased wet weight, body length, and condition factor of female fish at 1000 ng/L, and sex ratio was shifted toward female from 320 ng/L ZON. Only females at 1000 ng/L ZON revealed a 1.5-fold induction of plasma vitellogenin (VTG). Relative fecundity at 1000 ng/L recovered significantly during the depuration period. An increased condition factor in adult female F1 fish implies that exposure of F0 generation to 1000 ng/L ZON affected growth of F1 generation. A negative correlation between relative fecundity in the F1 generation (all groups exposed to 320 ng/L ZON) and the nominal ZON concentrations of the F0 exposure might indicate an influence of F0 exposure on reproductive performance of F1 generation. No exposure scenario affected fertility, hatch, embryo survival, and gonad morphology of zebrafish. Evaluating the environmental relevance of this data, the risk for fish to be harmed by exposure to ZON solely seems rather marginal, but ZON might contribute to the overall estrogenicity in the environment. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 21 Jun 2011 | 3:45 pm CEST

Prochloraz effects on biomarkers activity in zebrafish early life stages and adults

Abstract

Zebrafish early life stages (ELS) assays have been increasingly used to assess the toxicity of chemicals and waste waters, showing a great potential due to the wide variety of endpoints that can be incorporated in the test. Moreover, zebrafish ELS test have been proposed, mainly for ethical reasons, as a surrogate for tests with adults. In this work, the fungicide Prochloraz (PCZ) was used as a chemical model to compare sensitivities of embryos/larvae and adult zebrafish focusing on lethality and biomarkers as endpoints. Effects on embryo development were also assessed. Organization for economic cooperation and development (OECD) guidelines were followed and adapted to include the analyses of the biomarkers cholinesterase, glutathione S-transferase, and lactate dehydrogenase. The acute toxicity of PCZ for zebrafish ELS and adults seemed to be similar with 96h-LC50 values of 8.5 and 4.6 mg/L, respectively. However, biomarkers were only responsive in larvae indicating a higher sensitivity of this life stage at sublethal level. PCZ also proved to be teratogenic: at intermediate concentrations effects on embryo development could be noticed, including spine deformations, edemas, lack of pigmentation, slower heart rate, and complete hatching failure. At the lowest concentrations, the more relevant effects (edemas and abnormal absorption of the yolk sac) were observed after hatching. The measurement of biomarkers in the zebrafish ELS assay seems to a useful tool in the detection of chemical effects showing higher sensitivity than adults. Further research should focus on the link between biomarkers responses in larvae and effects at later life stages of zebrafish. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:49 pm CEST

Assessment of reproductive biomarkers in three-spined stickleback (Gasterosteus aculeatus) from sewage effluent recipients

Abstract

The aim of this study was to examine the occurrence of endocrine disruption close to sewage treatment plant effluent discharges along the Finnish Baltic Sea coast using a set of reproductive biomarkers present in adult three-spined stickleback (Gasterosteus aculeatus). Possible variation and sensitivity of the biomarkers during an entire reproductive period were also examined. The analysis of vitellogenin (VTG) for estrogenic activity and spiggin for androgenic activity, together with histopathological analysis indicated that sticklebacks were exposed to estrogenic loads sufficient to cause inappropriate production of VTG and to disrupt normal testicular structure in adult male sticklebacks. No androgenic disruption was observed. The results emphasize the need of a combination of several reproductive biomarkers in fish and repeated sampling for the detection of potential endocrine modulating substances under field condition. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:49 pm CEST

Antioxidative and antigenotoxic effect of vitamin E against patulin cytotoxicity and genotoxicity in HepG2 cells

Abstract

Patulin (PAT) is a mycotoxin produced in fruits, mainly in apples, by certain species of Penicillium, Aspergillus, and Byssochlamys. It has been shown that PAT is cytotoxic, genotoxic, and mutagenic in different cell types. Several studies incriminate the oxidative stress as a mechanism of PAT-mediated toxicity. In this context, our aim was to investigate the protective role of Vitamin E (Vit E), an antioxidant agent, against PAT induced cytotoxicity and genotoxicity in cultured HepG2 cells. The obtained results showed that addition of Vit E in cells treated with PAT significantly reduce cell mortality induced by this toxin. In the same conditions, Vit E decreased the intracellular level of ROS, reduced PAT induced p53 expression, and reversed PAT induced DNA damage. In addition, Vit E prevented significantly the percentage of chromosome aberrations induced by PAT in HepG2 cells in a concentration dependant manner. These results suggest that Vit E, an exogenous antioxidant agent, plays an important role in defense against PAT-induced cytotoxicity and genotoxicity, which confirms the involvement of oxidative stress in the induction of DNA damage by PAT in HepG2 cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:49 pm CEST

Catalase activity and innate immune response of Caenorhabditis elegans against the heavy metal toxin lead

Abstract

The heavy metal lead-induced oxidative stress on Caenorhabditis elegans was examined at the level of catalase activity and on innate immunity. Stress-induced C. elegans was exposed to Pseudomonas aeruginosaPA14::GFP for monitoring the impact at the physiological level. Role of catalase on the innate-immune responses of C. elegans was examined. PA14::GFP did not colonize lead pretreated C. elegans intestinal cells significantly compared to untreated controls, indicating stress-mediated upregulation of host-immunity. Semiquantitative PCR analyses of lead-exposed and PA14-infected C. elegans mRNA showed significant upregulation of candidate antimicrobial enzyme gene lys-7 after 24 h of exposures. Upregulation of metallothionein(mtl-1) when compared to mtl-2 in response to the lead suggesting active detoxification of metal by mtl-1. Exogenously provided Catalase (0.4–3.2 U) induced significant upregulation of lys-7 compared to controls. lys-7 upregulation during lead exposure was reconfirmed by real-time PCR. Confocal microscopy and fluorescence spectrophotometer analyses indicated that the lead pretreated C. elegans was significantly less colonized by PA14::GFP when compared to controls. Relative expression of ctl-1 and ctl-2 mRNA was measured using real time PCR and found to be regulated during lead exposures. Over all, the upregulation of antimicrobial gene expression appears to be correlated with the level of catalase during stress emphasizing their key roles in defensive mechanism(s). These results provide a link between the stress and related immune responses which can be explored in higher systems. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:48 pm CEST

Molecular mechanism of inflammatory response in mouse liver caused by exposure to CeCl3

Abstract

To investigate the molecular mechanism of inflammatory response in the mouse liver caused by exposure to CeCl3, we measured the liver indices, and cerium content, evaluated the liver histopathological section, detected serum biochemical parameters of liver function, and the immunoglobulin M (IgM) content, analyzed the liver mRNA and protein expression levels of Toll-like receptor 2, 4 (TLR2, TLR4), and inflammatory cytokines in liver using real-time quantitative reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. The results showed that exposure to CeCl3 decreased body weight and caused cerium accumulation in the mouse liver and histopathological changes of liver (such as inflammatory cell infiltration). Furthermore, biochemical assays suggested that CeCl3 could promote the activities of alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, pseudocholinesterase, and leucine aminopeptidase, decrease serum IgM, upregulate the levels of TLR2, TLR4, nuclear factor-κB (NF-κB), NF-κBp52, NF-κBp65, NF-κB-inducing kinase (NIK), IκB kinase α (IKK-α), IκB kinase β (IKK-β), and tumor necrosis factor-α (TNF-α) expression, and suppress NF-κB-inhibiting factor (IκB) and interleukin-2 (IL-2) expression in liver. Taken together, the inflammation of mice liver caused by exposure to CeCl3 might be closely associated with the alteration of inflammatory cytokine expressions in the mouse liver, the signal-transducing events happening in CeCl3-induced macrophages of liver sequentially might occur via activation of TLRs→TNF-α→NIK→IκB kinase (including IKK1, IKK2)→NF-κB (including NF-κBP52, NF-κBP65)→ inflammation. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:48 pm CEST

Investigation of biochemical responses of Bacopa monnieri L. upon exposure to arsenate

Abstract

Widespread contamination of arsenic (As) is recognized as a global problem due to its well-known accumulation by edible and medicinal plants and associated health risks for the humans. In this study, phytotoxicity imposed upon exposure to arsenate [As(V); 0–250 μM for 1–7 days] and ensuing biochemical responses were investigated in a medicinal herb Bacopa monnieri L. vis-à-vis As accumulation. Plants accumulated substantial amount of As (total 768 μg g−1 dw at 250 μM As(V) after 7 days) with the maximum As retention being in roots (60%) followed by stem (23%) and leaves (17%). The level of cysteine and total nonprotein thiols (NP-SH) increased significantly at all exposure concentrations and durations. Besides, the level of metalloid binding ligands viz., glutathione (GSH) and phytochelatins (PCs) increased significantly at the studied concentrations [50 and 250 μM As(V)] in both roots and leaves. The activities of various enzymes viz., arsenate reductase (AR), glutathione reductase (GR), superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and catalase (CAT) showed differential but coordinated stimulation in leaves and roots to help plants combat As toxicity up to moderate exposure concentrations (50 μM). However, beyond 50 μM, biomass production was found to decrease along with photosynthetic pigments and total soluble proteins, whereas lipid peroxidation increased. In conclusion, As accumulation potential of Bacopa may warrant its use as a phytoremediator but if Bacopa growing in contaminated areas is consumed by humans, it may prove to be toxic for health. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:48 pm CEST

Adverse influence of coumestrol on secretory function of bovine luteal cells in the first trimester of pregnancy

Abstract

Coumestrol is one of a few biologically active substances present in leguminous plants, which are widely used as fodder for ruminants. Depending on the doses, coumestrol acts on the reproductive processes as an estrogen-like factor or antiestrogen to evoke a decrease in ovulation frequency, elongation of estrous cycle duration. The aim of the current investigations was to study the influence of coumestrol on secretory function of luteal cells obtained from first trimester of pregnant cows. Luteal cells (2.5 × 105/mL) from 3rd to 5th, 6th to 8th, and 9th to 12th week of pregnancy were preincubated for 24 h and incubated with coumestrol (1 × 10−6 M) for successive 48 h and the medium concentrations of progesterone (P4), oxytocin (OT), prostaglandin (PG) E2 and F2α were determined. Moreover, the expression of mRNA for neurophysin-I/oxytocin (NP-I/OT; precursor of OT) and peptidyl-glycine-α-amidating mono-oxygenase (PGA, an enzyme responsible for post-translational OT synthesis) was determined after 8 h of treatment. Coumestrol did not affect P4 secretion but increased the secretion of OT from the cells collected at all stages of gestation studied. Hence, the ratio of P4 to OT was markedly decreased. Simultaneously, coumestrol increased the expression of NP-I/OT mRNA during 9th to 12th weeks of pregnancy, and mRNA for PGA during 3rd to 5th and 9th to 12th weeks of gestation. Furthermore, coumestrol decreased PGE2 secretion from luteal cells in all studied stages of pregnancy, while it affected PGF2α metabolite (PGFM) concentration only from week 3 to 5 of pregnancy. Obtained results suggest that coumestrol impairs secretory function of the corpus luteum (CL) and this way it can affect the maintenance of pregnancy in the cow. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:48 pm CEST

Multiwall carbon nano-onions induce DNA damage and apoptosis in human umbilical vein endothelial cells

Abstract

Growing evidence has indicated the potential adverse effects on cardiovascular system of some nanomaterials, including fullerenes. In this study, we have evaluated the biological effects of multiwall carbon nano-onions (MWCNOs) (average size of 31.2 nm, ζ potential of 1.6 mV) on human umbilical vein endothelial cells (HUVECs). It was found that MWCNOs exhibited a dose-dependent inhibitory effect on cell growth; EC50 was 44.12 μg/mL. Thus, three concentrations were chosen (0.2, 1, and 5 μg/mL) for further experiments. Flow cytometry analysis revealed that 1 and 5 μg/mL MWCNOs could induce apoptosis in HUVECs, the apoptotic rates were 12% and 24% at 24 h after exposure. On the other hand, MWCNOs did not affect the cell cycle distribution during 24 h period. Using γH2AX foci formation as an indicator for DNA damage, it was shown that 5 μg/mL MWCNOs can induce γH2AX foci formation in HUVECs at 6, 12, and 24 h after treatment, whereas 0.2 μg/mL MWCNOs induced γH2AX foci formation only at 6 h after treatment. In addition, all three concentrations of MWCNOs induced the generation of reactive oxygen species (ROS), and inhibition of ROS generation can partially decrease the γH2AX foci formation induced by MWCNOs. Taken together, these data first suggested that MWCNOs can induce DNA damage and apoptosis in HUVECs, and that ROS might be involved in this process. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Jun 2011 | 3:48 pm CEST

Phenethyl isothiocyanate promotes immune responses in normal BALB/c mice, inhibits murine leukemia WEHI-3 cells, and stimulates immunomodulations in vivo

Abstract

Enhanced cruciferous vegetable consumption is associated with the reduction of cancer incidence as shown in epidemiological studies. Phenethyl isothiocyanate (PEITC), one of the important compounds in cruciferous vegetables, has been shown to induce apoptosis in many types of human cancer cell lines, but there is no available information addressing the effects on normal and leukemia mice in vivo. The purpose of this study is to focus on the in vivo effects of PEITC on immune responses of normal and WEHI-3 leukemia BALB/c mice in vivo. Influences of PEITC on BALB/c mice after intraperitoneal (i.p.) injection with WEHI-3 cells and normal mice were investigated. In normal BALB/c mice, PEITC did not affect the body weight when compared to the olive oil treated animals. Moreover, PEITC promoted phagocytosis by macrophages from peripheral blood mononuclear cells (PBMC) and peritoneal cavity, increased the levels of CD11b and Mac-3, decreased the level of CD19 and promoted natural killer (NK) cell cytotoxic activity, but it did not alter the level of CD3. Also, PEITC enhanced T cell proliferation after concanavalin A (Con A) stimulation. Otherwise, PEITC increased the body weight, but decreased the weight of liver and spleen as compared to the olive oil-treated WEHI-3 leukemia mice. PEITC also increased the level of CD19, decreased the levels of CD3 and Mac-3 rather than influence in the level of CD11b, suggesting that the differentiation of the precursor of macrophages and T cells was inhibited, but the differentiation of the precursor of B cells was promoted in leukemia mice. Furthermore, PEITC enhanced phagocytosis by monocytes and macrophages from PBMC and peritoneal cavity, and also promoted the NK cell cytotoxic activity in comparison with the group of leukemia mice. Based on these observations, the biological properties of PEITC can promote immune responses in normal and WEHI-3 leukemia mice in vivo. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 27 May 2011 | 3:34 pm CEST

Retinoic acid influences the embryoid body formation in mouse embryonic stem cells by induction of caspase and p38 MAPK/JNK-mediated apoptosis

Abstract

Although all-trans retinoic acid (RA), the oxidative metabolite of vitamin A, is essential for normal development, high levels are teratogenic in many species. RA results in immediate effects on the preimplantation embryo and on blastocyst development in vitro and in vivo. To further elucidate the cellular mechanisms of early postimplantation embryo development induced by RA, we present an embryonic cell line, B5, as a candidate system for the investigation of these processes. We used undifferentiated ES cells as the model, which is from the undifferentiated status to differentiated status [embryoid body (EB) formation] mimicking postimplantation embryo development (egg-cylinder stage of embryo formation) to clarify the cellular mechanism of action of RA in the implanted blastocysts and cell apoptosis following the series of exposures to differing RA concentrations. Using an in vitro model, we identified the impact of RA on undifferentiated embryonic stem (ES) cells, including inhibition of cell proliferation and induction of cell apoptosis. JNK, P-38 and caspase activation were shown in the nature of RA-triggered apoptotic signaling in ES cells. The carry-on influences of RA on the ES cell were shown in the formation of EB from the pretreated ES cells. RA resulted in apparent impact on undifferentiated ES cells in vitro, with increased numbers of apoptotic cells initially and inhibited cell proliferation, which led to decreased size of EB. The process of EB formation (mimicking the early postimplantation embryo development) is regulated by RA-induced apoptosis through the activation of caspase and P38 MAPK/JNK pathway. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 27 May 2011 | 3:34 pm CEST

Excessive fluoride induces endoplasmic reticulum stress and interferes enamel proteinases secretion

Abstract

Protein retention in the enamel layer during tooth formation is well known to be associated with dental fluorosis but the underlying mechanism is unclear. The functions of the endoplasmic reticulum (ER) correlate directly with secreted protein metabolism. We used an ameloblast-derived cell line to determine whether excessive amounts of fluoride cause ER stress, and whether this interferes with the secretion of enamel matrix proteinases. ER stress activates a signaling network called the unfolded protein response (UPR). Here, we used real-time RT-PCR and immunofluorescence to study the effect of fluoride on the expression, translation, and secretion of UPR transcription factors in ameloblast-like cells. Measurement of both the gene and protein expression of UPR transcription factors indicated that high-dose fluoride increases the expression of UPR transcription factors in a dose-dependent manner. We also used ELISA to detect and quantify the enamel proteinases secreted by ameloblasts. We found a corresponding decrease in extracellular secretion of the enamel proteinases matrix metalloproteinase-20 and kallikrein-4, after exposure to fluoride. Furthermore, correlation analysis indicated that the expression of UPR transcription factors showed a strong inverse correlation with that of enamel proteinases. The results suggest that high-dose fluoride initiates an ER stress response in ameloblasts and induces the UPR, which interferes with the synthesis and secretion of enamel proteinases. Taken together, these results suggest that excessive ingestion of fluoride during tooth formation can decrease the secretion of proteinases, thus causing protein retention in the enamel layer, indicating that the ER stress response may be responsible for dental fluorosis. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 27 May 2011 | 3:33 pm CEST

Influence of increasing temperature and salinity on herbicide toxicity in estuarine phytoplankton

Abstract

Ecological risk assessments are, in part, based on results of toxicity tests conducted under standard exposure conditions. Global climate change will have a wide range of effects on estuarine habitats, including potentially increasing water temperature and salinity, which may alter the risk assessment of estuarine pollutants. We examined the effects of increasing temperature and salinity on the toxicity of common herbicides (irgarol, diuron, atrazine, and ametryn) to the phytoplankton species Dunaliella tertiolecta. Static 96-h algal bioassays were conducted for each herbicide under four exposure scenarios: standard temperature and salinity (25°C, 20 ppt), standard temperature and elevated salinity (25°C, 40 ppt), elevated temperature and standard salinity (35°C, 20 ppt), and elevated temperature and elevated salinity (35°C, 40 ppt). The endpoints assessed were algal cell density at 96 h, growth rate, chlorophyll a content, lipid content, and starch content. Increasing exposure temperature reduced growth rate and 96-h cell density but increased the cellular chlorophyll and lipid concentrations of the control algae. Exposure condition did not alter starch content of control algae. Herbicides were found to decrease growth rate, 96 h cell density, and cellular chlorophyll and lipid concentrations, while starch concentrations increased with herbicide exposure. Herbicide effects under standard test conditions were then compared with those observed under elevated temperature and salinity. Herbicide effects on growth rate, cell density, and starch content were more pronounced under elevated salinity and temperature conditions. To encompass the natural variability in estuarine temperature and salinity, and to account for future changes in climate, toxicity tests should be conducted under a wider range of environmental conditions. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 27 May 2011 | 3:33 pm CEST

Developmental exposure to decabrominated diphenyl ether (BDE-209): Effects on sperm oxidative stress and chromatin dna damage in mouse offspring

Abstract

Polybrominated diphenyl ethers (PBDEs) are used as brominated flame retardants and have been found in human milk in recent years. This study investigates whether prenatal exposure to decabrominated diphenyl ether (BDE-209) induces sperm dysfunction in male offspring. Pregnant CD-1 mice were gavaged once daily with corn oil (control), 10, 500, and 1500 mg kg−1 body weight of BDE-209 from day 0 of gestation to day 17. The outcomes of male reproductive parameters were assessed on postnatal day 71. Anogenital distance, sperm-head abnormalities, and testicular histopathology were significantly affected in male offspring prenatally exposed to 1500 mg kg−1. Significant increases in the tendency for sperm DNA denaturation (αT) induction and the DNA fragmentation index (DFI) were found in those exposed to 10, 500, and 1500 mg kg−1 (P < 0.05). We observed a significant increase of sperm hydrogen peroxide (H2O2) generation in the 10 and 1500 mg/kg/day groups compared to the control group (P < 0.05). Although our findings suggested that the mechanisms underlying BDE-209-induced sperm DNA damage and H2O2 generation might not be represented as a dose-response relationship, we found that the greater the excess production of sperm H2O2, the greater the sperm αT (r = 0.65, P = 0.0155) and DFI (r = 0.53, P = 0.002). In conclusion, developmental exposure to BDE-209 induced sperm-head abnormality, oxidative stress, chromatin DNA damage, and testicular histopathological changes. These findings suggest that BDE-209-induced male reproductive effects might involve the formation of sperm H2O2 which attacks nucleic acids via H2O2 generation. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 27 May 2011 | 3:33 pm CEST

Inhibition of PP2A and the consequent activation of JNK/c-Jun are involved in tributyltin-induced apoptosis in human amnionic cells

Abstract

Tributyltin (TBT), a highly toxic environmental contaminant, has been shown to induce mitochondrial-dependent apoptosis in several mammalian cells. However, the upstream signal transduction pathways involved in TBT-induced apoptosis are still not fully elucidated. In this study, the protein phosphatase (PP) 2A, microtubule organization, and mitogen-activated protein kinases (MAPKs), including JNK, p38 and their downstream transcription factors, c-Jun and ATF-2, respectively, were investigated in human amnionic cells treated by TBT. Furthermore, the activation of procaspase-3 after blocking either one of these MAPK pathways was also observed. The results showed that TBT effectively induced apoptosis characterized by caspase-3 activation. In apoptotic cells, the inhibition of PP2A activity and microtubule depolymerization was detected. Additionally, JNK and p38, as well as their downstream targets, c-Jun and ATF-2, were activated. Moreover, a JNK inhibitor, but not p38 inhibitor, significantly reduced caspase-3 activation. It can be concluded that the inhibition of PP2A may (1) play as a role in the activation of JNK and c-Jun and the concomitant promotion of microtubule depolymerization and (2) lead to the activation of caspase-3 in TBT-induced apoptotic cells. The results of this study suggest a critical role of PP2A in the TBT toxicity mechanism. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 27 May 2011 | 3:33 pm CEST

The toxic effects of nickel chloride on liver, erythropoiesis, and development in Wistar albino preimplanted rats can be reversed with selenium pretreatment

Abstract

The exposure to nickel chloride (NiCl2) can cause hematotoxicity and hepatotoxicity and canaffect development. The present study pertains to the protective effect of selenium (Se) against NiCl2-induced toxicity in preimplanted Wistar albino rats. The subcutaneous (s.c.) administration of 25 or 50 mg/kg of NiCl2 to Wistar albino rats on day 3 of gestation induced an immediate and significant decrease in maternal body weight and anemia 2 days after treatment. In addition, an increase in plasma aspartate aminotransferase (AST) was observed. These effects were maintained on day 20 of gestation. Moreover, a significant increase in plasma alanine aminotransferase (ALT) levels was observed with the administration of 25 mg/kg of NiCl2. Conversely, administration of 50 mg/kg of NiCl2 by s.c. injection increased erythropoiesis at day 20 of gestation and decreased platelets counts. In addition, administration of 100 mg/kg of NiCl2 markedly reduced the maternal body weight and number of live fetuses and increased fetal loss, predominantly at the end of the experimental period. All dose levels of NiCl2 caused an alteration in the hepatic histoarchitecture. When 0.3-mg/kg Se was injected s.c. with 100-mg/kg NiCl2, the levels of plasma AST and ALT and the structure of the liver were restored. Administration of 20 mg/L/day of NiCl2 in the drinking water significantly reduced the maternal body weight at day five of gestation as well as erythropoiesis during the exposure period. The present study suggests that Se can counteract the nocuous effect of nickel on the liver; however this antioxidant did not prevent alterations in development and erythropoiesis. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 26 May 2011 | 5:32 pm CEST

Bio-distribution and in vivo antioxidant effects of cerium oxide nanoparticles in mice

Abstract

Cerium oxide nanoparticles have oxygen defects in their lattice structure that enables them to act as a regenerative free radical scavenger in a physiological environment. We performed a comprehensive in vivo analysis of the biological distribution and antioxidant capabilities of nanoceria administered to mice perorally (PO), intravenously (IV), or intraperitoneally (IP) by dosing animals weekly for 2 or 5 weeks with 0.5 mg kg−1 nanoceria. Next, we examined if nanoceria administration would decrease ROS production in mice treated with carbon tetrachloride (CCl4). Our results showed that the most extensive and cumulative nano-deposition was via IV and IP administered while PO administration showed mice excreted greater than 95% of their nanoceria within 24 h. Organ deposition for IV and IP mice was greatest in the spleen followed by the liver, lungs, and kidneys. Elimination for all administration routes was through feces. Nanoceria administration showed no overt toxicity, however, WBC counts were elevated with IV and IP administration. Our in vivo studies show that nanoceria administration to mice with induced liver toxicity (by CCl4) showed similar findings to mice treated with N-acetyl cystine (NAC), a common therapeutic to reduce oxidative stress. Taken together, our studies show that nanoceria remains deposited in tissues and may decrease ROS, thereby suggesting that cerium oxide nanoparticles may be a useful antioxidant treatment for oxidative stress. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 26 May 2011 | 5:32 pm CEST

Safrole induces cell death in human tongue squamous cancer SCC-4 cells through mitochondria-dependent caspase activation cascade apoptotic signaling pathways

Abstract

Safrole is one of important food-borne phytotoxin that exhibits in many natural products such as oil of sassafras and spices such as anise, basil, nutmeg, and pepper. This study was performed to elucidate safrole-induced apoptosis in human tongue squamous carcinoma SCC-4 cells. The effect of safrole on apoptosis was measured by flow cytometry and DAPI staining and its regulatory molecules were studied by Western blotting analysis. Safrole-induced apoptosis was accompanied with up-regulation of the protein expression of Bax and Bid and down-regulation of the protein levels of Bcl-2 (up-regulation of the ratio of Bax/Bcl-2), resulting in cytochrome c release, promoted Apaf-1 level and sequential activation of caspase-9 and caspase-3 in a time-dependent manner. We also used real-time PCR to show safrole promoted the mRNA expressions of caspase-3, -8, and -9 in SCC-4 cells. These findings indicate that safrole has a cytotoxic effect in human tongue squamous carcinoma SCC-4 cells by inducing apoptosis. The induction of apoptosis of SCC-4 cells by safrole is involved in mitochondria- and caspase-dependent signal pathways. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 17 May 2011 | 4:14 pm CEST

Effects of exogenous methionine on arsenic burden and NO metabolism in brain of mice exposed to arsenite through drinking water

Abstract

The aim of this study was to explore the effects of exogenous methionine (Met) on arsenic burden and metabolism of nitric oxide (NO) in the brain of mice exposed to arsenite via drinking water. Mice were exposed to sodium arsenite through drinking water contaminated with 50 mg/L arsenic for four consecutive weeks, and treated intraperitoneally with saline solution, 100 mg/kg body weight (b.w), 200 mg/kg b.w or 400 mg/kg b.w of Met, respectively at the fourth week. Levels of inorganic arsenic (iAs), monomethylarsenic acid (MMAs), and dimethylarsenic acid (DMAs) in the liver, blood and brain were determined by method of hydride generation coupled with atomic absorption spectrophotometry. Nitric oxide synthase (NOS) activities and NO levels in the brain were determined by colorimetric method. Compared with mice exposed to arsenite alone, administration of Met increased significantly the primary methylation ratio in the liver, which resulted in decrease of percent iAs and increase of percent DMAs in the liver, and decrease of iAs, MMAs and total arsenic levels (TAs) in the blood and DMAs and TAs in the brain. NOS activities and NO levels in the brain of mice exposed to arsenite alone were significantly lower than those in control, however administration of Met could increase significantly NO levels. Findings from this study suggested that exogenous Met could benefit the primary arsenic methylation in the liver, which might increase the production of methylated arsenicals and facilitate arsenic excretion. As a consequence, arsenic burden in both blood and brain was reduced, and toxic effects on NO metabolism in the brain were ameliorated. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 10 May 2011 | 3:49 pm CEST

Metiram-induced nephrotoxicity in albino mice: Effect of licorice aqueous extract

Abstract

The present study was designed to estimate the effect of aqueous extract of licorice on metiram toxicity in mice. Treating mice with metiram at a dose level of [1/2] LD50 daily for 3 weeks induced many histological changes in the kidney cortex. The renal tubules lost their characteristic appearance and their lining epithelial cells were degenerated. The glomeruli were atrophied and the renal blood vessels were congested. The intertubular spaces infiltrated by inflammatory leukocytic cells. Metiram caused an increase in proliferating cell nuclear antigen (PCNA) expression in nuclei of tubular epithelial cells. Metiram also caused marked elevation in serum creatinine and blood urea nitrogen. Treating animals with metiram and licorice aqueous extract led to an improvement, in both biochemical and histopathological alterations. These results proved that licorice had an ameliorative effect against kidney injury induced by metiram and this effect may be attributed to its antioxidant activity. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:04 pm CEST

Study of cytoskeletal changes induced by okadaic acid in HL-7702 liver cells and development of a fluorimetric microplate assay for detecting diarrhetic shellfish poisoning

Abstract

Diarrhetic shellfish poisoning (DSP) is a gastrointestinal illness with symptoms such as diarrhea, nausea, vomiting, headache, chills and moderate to severe abdominal pain. DSP has been recognized as a worldwide public health problem, causing great concern to the shellfish industry. Accumulation of DSP in shellfish is an unpredictable phenomenon that necessitates the implementation of a widespread collection and thorough monitoring program for mollusk toxicity. Therefore, development of accurate analytical protocols for the rapid determination of toxicity levels would be necessary. In this study we investigated cytoskeletal changes induced by okadaic acid in HL-7702 Liver Cells and developed a new cytotoxicity assay for detection and quantitation of DSP. This assay is based on fluorometric of F-actin depolymerization induced by okadaic acid (OA) compounds in HL-7702 liver cell line. The measurable range of OA was 2.5 ∼ 40 nmol/L. The detection limit of the F-actin assay for OA was 2.01 μg/100 g muscles in shellfish extracts. The performance of this assay has been evaluated by comparative analysis of shellfish samples by the fluorescent assay, mouse bioassay, and ELISA assay. Comparison of the results by all three methods revealed excellent consistency, the results of fluorescent assay were in significant correlation with ELISA assay (R2 = 0.830). Examination of F-actin assay is very convenient, rapid, and sensitive, which can be used to quantify the amount of OA in shellfish samples. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:04 pm CEST

Fetal adrenal development: Comparing effects of combined exposures to PCB 118 and PCB 153 in a sheep model

Abstract

This study investigated the effects of exposure to the ubiquitous contaminants polychlorinated biphenyls (PCBs) on the fetal adrenal cortex and on plasma cortisol using the domestic sheep (Ovis aries) as a model. Pregnant ewes were intendedly subjected to oral treatment with PCB 153 (98 μg/kg bw/day), PCB 118 (49 μg/kg bw/day) or the vehicle corn oil from mating until euthanasia on gestation day 134 (±0.25 SE). However, because of accidental cross-contamination occurring twice causing a mixed exposure scenario in all three groups, the focus of this paper is to compare three distinct groups of fetuses with different adipose tissue PCB levels (PCB 153high, PCB 118high and low, combined groups) rather than comparing animals exposed to single PCB congeners to those of a control group. When comparing endocrine and anatomical parameters from fetuses in the PCB 153high (n = 13) or PCB 118high (n = 14) groups with the low, combined group (n = 14), there was a significant decrease in fetal body weight (P < 0.05), plasma cortisol concentration (P < 0.001) and adrenal cortex thickness (P < 0.001). Furthermore, adrenal weight was decreased and plasma ACTH was increased only in the PCB 118high group. Expression of several genes encoding enzymes and receptors related to steroid hormone synthesis was also affected and mostly down-regulated in fetuses with high PCB tissue levels. In conclusion, we suggest that mono-and di-ortho PCBs were able to interfere with growth, adrenal development and cortisol production in the fetal sheep model. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:04 pm CEST

Effects of quercetin and chrysin on 2,3,7,8-tetrachlorodibenzo-p-dioxin induced hepatotoxicity in rats

Abstract

The objective of current study is to investigate the effects of the administration of chrysin (CH) and quercetin (Q) on rat liver in which oxidative and histological damage had been induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Rats were randomly divided into six equal groups. TCDD was orally administered at the dose of 2 μg/kg/week, and Q and CH were orally administered at the doses of 20 mg/kg day and 50 mg/kg/day, respectively, by gavages dissolved in corn oil. The liver samples to be analyzed for the determination of oxidative and histological alternations were taken from rats at 60 days. The results indicated that although 2,3,7,8-TCDD significantly induced (P ≤ 0.01) lipid peroxidation (increase of MDA levels), it positively affected oxidant/antioxidant system (a decline in the levels of GSH, CAT, GSH-Px, and CuZn-SOD) in rats significantly. The histological changes observed in the liver correlated with the biochemical findings. However, these effects of TCDD on oxidative and histological changes were eliminated by Q and CH treatment. In conclusion, TCDD caused an adverse effect on rat's liver. When Q and CH were given together with TCDD, they prevented hepatotoxicty induced by TCDD. Thus, it is thought that Q and CH may be useful as a new category of anti-TCDD toxicity agent. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:03 pm CEST

Bacterial biosensors for evaluating potential impacts of estrogenic endocrine disrupting compounds in multiple species

Abstract

To study the effects and possible mechanisms of suspected endocrine disrupting compounds (EDCs), a wide variety of assays have been developed. In this work, we generated engineered Escherichia coli biosensor strains that incorporate the ligand-binding domains (LBDs) of the β-subtype estrogen receptors (ERβ) from Solea solea (sole), and Sus scrofa (pig). These strains indicate the presence of ligands for these receptors by changes in growth phenotype, and can differentiate agonist from antagonist and give a rough indication of binding affinity via dose-response curves. The resulting strains were compared with our previously reported Homo sapiens ERβ biosensor strain. In initial tests, all three of the strains correctly identified estrogenic test compounds with a high degree of certainly (Z′ typically greater than 0.5), including the weakly binding test compound bisphenol A (BPA) (Z′ ≈ 0.1–0.3). The modular design of the sensing element in this strain allows quick development of new species-based biosensors by simple LBD swapping, suggesting its use in initial comparative analysis of EDC impacts across multiple species. Interestingly, the growth phenotypes of the biosensor strains indicate similar binding for highly estrogenic control compounds, but suggest differences in ligand binding for more weakly binding EDCs. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:03 pm CEST

Effects of trifluralin on the mouse ovary

Abstract

Trifluralin, a herbicide used to protect many arable and horticultural crops, was evaluated for its potential toxicity on the mammalian ovary. To this end, adult female mice were fed or not (control) with a trifluralin-enriched diet (150 mg/kg body weight/day) during gestation and lactation. After weaning, 3-week-old female mice from either trifluralin-treated or control groups were used to evaluate whether the exposure to this herbicide in utero and during lactation could induce stress responses in the ovary. It was found that trifluralin exposure caused a significantly higher level of p53, but not of pRb, in the whole ovary, and in particular in granulosa cells. TUNEL staining showed that herbicide treatment did not increase the apoptotic index of the somatic compartment. Also oocyte fertilizability was unaffected, as metaphase II oocytes retrieved from treated mice were capable of forming male and female pronuclei after in vitro fertilization as control mice. However, trifluralin determined a slightly higher number of oocytes with cytoplasmic degeneration compared with control animals. In conclusion, our results suggest that exposure to a low trifluralin dose during pregnancy and lactation does not impair oocyte quality, but can induce a stress response in ovarian somatic cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:03 pm CEST

Acute toxicity and superficial damage to goldfish from the ionic liquid 1-methyl-3-octylimidazolium bromide

Abstract

In the present study, goldfish toxicity and superficial damage from 1-methyl-3-octylimidazolium bromide ([C8mim]Br) exposure were evaluated by an acute toxicity test. These results show that the 24-h 50% lethal concentration for [C8mim]Br in goldfish is 244 mg L−1, and this indicates that [C8mim]Br is a chemical with moderate or low toxicity to organisms. Scanning electronic microscope and histological observations revealed that acute exposure to [C8mim]Br induced obvious superficial damage to the skin, gill filaments, and intestinal villi of the goldfish, and this suggests that the skin, gills, and intestines may be the first direct targets of the ionic liquid in this fish. Histological examination also indicated that [C8mim]Br-exposure caused damage to the goldfish's hepatopancreas and kidney, consisting mainly of hepatic cords in a loose connection, hepatic cytoplasmic vacuolation, renal parenchyma vacuolization, and intumescence of the renal tubule. In addition, we found that [C8mim]Br caused a significant increase in malondialdehyde (MDA) level in the hepatopancreases from these goldfish, and thus we suggest that the MDA level may be a biomarker of [C8mim]Br-toxicity in goldfish. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:03 pm CEST

Toxicologic and immunologic effects of perinatal exposure to the brominated diphenyl ether (BDE) mixture DE-71 in the Sprague-Dawley rat

Abstract

Brominated diphenyl ethers (BDEs) are persistent environmental contaminants found in human blood, tissues, and milk. To assess the impact of the commercial BDE mixture DE-71 on the developing immune system in relation to hepatic and thyroid changes, adult (F0) rats were exposed to DE-71 by gavage at doses of 0, 0.5, 5, or 25 mg/kg body weight (bw)/d for 21 weeks. F0 rats were bred and exposure continued through gestation, lactation and postweaning. F1 pups were weaned and exposed to DE-71 by gavage from postnatal day (PND) 22 to 42. On PND 42, half of the F1 rats were assessed for toxicologic changes. The remaining F1 rats were challenged with the T-dependent antigen keyhole limpet hemocyanin (KLH) and immune function was assessed on PND 56. Dose-dependent increases in total BDE concentrations were detected in the liver and adipose of all F0 and F1 rats. In F0 rats, increased liver weight, hepatocellular hypertrophy, and decreased serum thyroxine (T4) were characteristic of DE-71 exposure. In F1 rats perinatal DE-71 exposure caused a nondose-dependent increase in body weight and dose-dependent increases in liver weight and hepatocellular hypertrophy. Serum T3 and T4 levels were decreased. In spleen from DE-71 exposed rats the area occupied by B cells declined while the area occupied by T cells increased; however, cellular and humoral immune responses to KLH challenge were not altered. Thus hepatic and thyroid changes in rats exposed perinatally to DE-71 were associated with altered splenic lymphocyte populations, an effect which has been linked to hypothyroidism. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:03 pm CEST

PFOS and PCB 153 have direct adverse effects on neonatal testis modeled using a coculture of primary gonocyte and sertoli cells

Abstract

Perfluorooctane sulfonate (PFOS) is widely used in industry; it is nonbiodegradable and persistent in the human body and in the environment. Although reports have indicated that young people might have higher PFOS levels in serum or blood than do older people, its adverse effects on neonatal testicular cells had not been investigated previously. PCB 153 is one of the most prevalent polychlorinated biphenyl (PCB) congeners in biological tissues, but the direct adverse effect of PCB 153 on neonatal testis remains unclear. In this study, we exposed a neonatal Sertoli cell/gonocyte coculture system to PFOS and PCB 153 individually at concentrations of 0, 1, 10, 50, and 100 μM for 24 h. Exposure to either compound reduced the cell viability and induced the production of reactive oxygen species (ROS) in dose-dependent manners, with PCB 153 having a greater effect than PFOS. Whereas PCB 153 induced apoptosis significantly from 10 μM, PFOS induced no obvious change. Morphologically, both PCB 153 and PFOS induced changes in the vimentin and actin filaments in the Sertoli cells, as investigated using confocal argon ion laser scanning microscopy; here, PFOS exhibited a more dramatic effect than did PCB 153. Furthermore, doses of 50 μM for PFOS and 10 μM for PCB 153 were the key concentrations that produced significant differences between the control and exposure groups. We suggest that both PCB 153 and PFOS directly affect neonatal gonocyte and Sertoli cells; the production of ROS and the change in the cytoskeleton in Sertoli cells might be causes. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:03 pm CEST

Involvement of oxidative stress in methyl parathion and parathion-induced toxicity and genotoxicity to human liver carcinoma (HepG2) cells

Abstract

Methyl parathion (C8H10NO5PS) and parathion (C10H14NO5PS) are both organophosphate insecticides (OPI) widely used for household and agricultural applications. They are known for their ability to irreversibly inhibit acetylcholinesterase which often leads to a profound effect on the nervous system of exposed organisms. Many recently published studies have indicated that human exposure to OPI may be associated with neurologic, hematopoietic, cardiovascular, and reproductive adverse effects. Studies have also linked OPI exposure to a number of degenerative diseases including Parkinson's, Alzheimer's, and amyotrophic lateral sclerosis. Also, oxidative stress (OS) has been reported as a possible mechanism of OPI toxicity in humans. Hence, the aim of the present investigation was to use human liver carcinoma (HepG2) cells as a test model to evaluate the role of OS in methyl parathion- and parathion-induced toxicity. To achieve this goal, we performed the MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay for cell viability, lipid peroxidation assay for malondialdehyde (MDA) production, and Comet assay for DNA damage, respectively. Results from MTT assay indicated that methyl parathion and parathion gradually reduce the viability of HepG2 cells in a dose-dependent manner, showing 48 h-LD50 values of 26.20 mM and 23.58 mM, respectively. Lipid peroxidation assay resulted in a significant increase (P < 0.05) of MDA level in methyl parathion- and parathion-treated HepG2 cells compared with controls, suggesting that OS plays a key role in OPI-induced toxicity. Comet assay indicated a significant increase in genotoxicity at higher concentrations of OPI exposure. Overall, we found that methyl-parathion is slightly less toxic than parathion to HepG2 cells. The cytotoxic effect of these OPI was found to be associated, at least in part, with oxidative cell/tissue damage. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 4 May 2011 | 5:03 pm CEST

Effects of waterborne acephate exposure on antioxidant responses and acetylcholinesterase activities in Synechogobius hasta

Abstract

The present study was conducted to determine the 24, 48, 72, and 96-h median lethal concentration (LC50) of acephate and investigate the antioxidant response and acetylcholinesterase (AChE) activities in liver, gill, and spleen of Synechogobius hasta exposed to 0 (control), 5, and 10 mg/L acephate, at the fixed interval time of 24, 48, 72, and 96 h, respectively. LC50 value was 60.83 mg/L at 24 h, 51.36 mg/L at 48 h, 47.07 mg/L at 72 h and 40.13 mg/L at 96 h, respectively. Dismutase (SOD), catalase (CAT), AChE activities, and malondialdehyde (MDA) levels in these tissues for the control remained stable over the exposure period. However, for the two tested groups, tissue-, dose-, and time-dependent responses of these parameters were observed in S. hasta. In general, hepatic SOD and CAT activities were significantly inhibited at 24 h, activated, and increased at 48 h, but again inhibited from 48 to 96 h in fish exposed to the two tested concentrations. Hepatic MDA levels of fish for the two tested concentration peaked at 48 h, significantly higher than the control. Hepatic AChE activity was inhibited at 24 h, peaked at 48 h, and then declined at 72 h for the two tested groups. For gills, the highest SOD and CAT activities for the two tested groups were observed at 48 h, higher than the control. AChE activities for the two tested groups were significantly inhibited at 24 h, but activated at 48 h. At 96 h, AChE activities among the treatments showed no significant differences. Gill MDA levels at 48 h for the tested groups were significantly higher than the control, but showed no significant differences at 24 and 72 h among the treatments. In spleen, SOD and CAT activities at 48 h for the two tested groups were significantly higher than those in the control, but at 96 h the vice versa was true. Spleenic AChE activities and MDA levels for the two tested groups were inhibited at 24 h, activated at 48 h, and then were again inhibited at 72 h. Based on these observations earlier, the results obtained in our study will have important toxicological implications for waterborne acephate pollution and, meantime, provide the basis for the effective risk assessment of acephate in water environment and appropriate safety recommendations for fish. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 1 Apr 2011 | 2:54 pm CEST

Impact of dihydrolipoic acid on mouse embryonic stem cells and related regulatory mechanisms

Abstract

α-Lipoic acid (LA) is a thiol with antioxidant properties that protects against oxidative stress-induced apoptosis. LA is absorbed from the diet, taken up by cells and tissues, and subsequently reduced to dihydrolipoic acid (DHLA). Recently, DHLA has been used as the hydrophilic nanomaterial preparations, and therefore, determination of its bio-safety profile is essential. In this article, we show that DHLA (50–100 μM) induces apoptotic processes in mouse embryonic stem cells (ESC-B5), but exerts no injury effects at treatment dosages below 50 μM. Higher concentrations of DHLA (50–100 μM) directly increased the reactive oxygen species (ROS) content in ESC-B5 cells, along with a significant increase in cytoplasmic free calcium and nitric oxide (NO) levels, loss of mitochondrial membrane potential (MMP), activation of caspases-9 and −3, and cell death. Pretreatment with NO scavengers suppressed the apoptotic biochemical changes induced by 100 μM DHLA and promoted the gene expression levels of p53 and p21 involved in apoptotic signaling. Our results collectively indicate that DHLA at concentrations of 50–100 μM triggers apoptosis of ESC-B5 cells, which involves both ROS and NO. Importantly, at doses of less than 50 μM (0–25 μM), DHLA does not exert hazardous effects on ESC-B5 cell properties, including viability, development and differentiation. These results provide important information in terms of dosage safety and biocompatibility of DHLA to facilitate its further use as a precursor for biomaterial preparation. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 1 Apr 2011 | 2:53 pm CEST

Micronucleus test and comet assay for the evaluation of zebrafish genomic damage induced by erythromycin and lincomycin

Abstract

An enormous quantity of pharmacologically active principles are currently being introduced into the environment, with consequent escalation of environmental problems, but only a small number of studies are focusing on an assessment of their genotoxic effects. The aim of this article is to assess the genotoxic effects of erythromycin, lincomycin, and of a combination of these two antibiotics on the genome of the zebrafish. The genotoxicity of the two antibiotics was assessed by applying the micronucleus test to erythrocytes and performing a Comet assay on erythrocytes and hepatocytes. The fish were exposed to antibiotics at different concentrations and times of exposure, under standard laboratory conditions. Depending on the different experimental conditions, erythromycin and lincomycin induced a significant increase in DNA migration (tail moment) and a significant increase in micronuleus frequency. We also conducted an analysis on the activation of repair mechanisms when the genotoxic agent was removed. Only a few of the cells displayed a decrease in damage under these test conditions.© 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:49 pm CET

Acute toxicity of commonly used forestry herbicide mixtures to Ceriodaphnia dubia and Pimephales promelas

Abstract

Because many herbicides selectively control specific species or types of vegetation, they are often applied as mixtures to achieve better control over undesirable vegetation. When herbicides are applied in forest ecosystems, streams, ponds, and other bodies of water are typically protected by buffer zones in which no herbicide is applied. However, in some landscapes, small wetlands and streams are difficult to see and avoid, thus the potential acute toxicity of herbicide mixtures to aquatic organisms is of interest, yet it has not been well-studied. We examined the acute toxicity of 23 different herbicide mixtures to Ceriodaphnia dubia and fathead minnows (Pimephales promelas) at environmentally relevant concentrations, and, where possible, characterized mixture interactions using Marking's Additive Index. Maximum exposure concentrations were equivalent to applying the maximum allowable rate for each component directly to the surface of a 6-in. deep pond with no dissipation following application. Under the conditions of this study, herbicide formulations containing Accord Concentrate (glyphosate), Arsenal AC (imazapyr), Chopper (imazapyr), Escort (metsulfuron methyl), Oust XP (sulfometuron methyl), and Velpar L (hexazinone) were not associated with appreciable acute toxicity to fathead minnows or C. dubia when used alone or in mixtures with each other and various surfactants and adjuvants. Herbicide mixtures for which Additive Indexes could be calculated exhibited primarily antagonistic or simple additive toxicity. In the few cases where synergistic toxicity was observed, the degree of synergism was slight, never exceeding approximately twice the effect estimated based on additive toxicity. Based on the results of this study, neither acute toxicity nor enhanced acute aquatic toxicity due to synergistic mixture effects appears to be a significant concern for applications of the herbicide mixtures most commonly used in forestry. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:49 pm CET

Evaluation of chlorinated benz[a]anthracene on hepatic toxicity in rats and mutagenic activity in Salmonella typhimurium

Abstract

Chlorinated benz[a]anthracenes (Cl-BaA) are halogenated aromatic compounds (typified by dioxins) found in the environment at relatively high concentrations. Fischer 344 rats were intragastrically administered 0, 1, or 10 mg of Cl-BaA or its parent compound benz[a]anthracene (BaA) per kg of body weight for 14 consecutive days. Both chemicals at 10 mg/kg/day inhibited the gain in body weight, and consequent increase in relative liver weight. Hepatic gene expression of cytochrome P450 (CYP) 1A1, 1A2, and 1B1 was significantly stimulated by administration of BaA (10 mg/kg/day) compared with the control. After administration of Cl-BaA, only the CYP1A2 gene was significantly induced, even at the lower dosage; CYP1A1 and 1B1 mRNA levels remained unchanged in Cl-BaA-treated rats compared with controls. To elucidate the role of such Cl-BaA exposure and induced CYPs at toxicity onset, we investigated the mutagenicity of BaA and Cl-BaA using Salmonella typhimurium TA98 and TA100. BaA and Cl-BaA at 10 μg/plate produced positive results in both strains in the presence of rat S-9. Incubation of Cl-BaA with recombinant rat CYP1A2 produced a significantly higher number of revertant colonies in TA98 and TA100 than in controls, but no such change was observed for BaA. In conclusion, BaA changes its own physiological and toxicological actions by its chlorination; (1) daily exposure to Cl-BaA selectively induces hepatic CYP1A2 in rats and (2) Cl-BaA induces frameshift mutations in the presence of CYP1A2, although BaA does not exert mutagenicity. This indicates that CYP1A2 may metabolize Cl-BaA to active forms. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:49 pm CET

p,p'-DDE induces apoptosis and mRNA expression of apoptosis-associated genes in testes of pubertal rats

Abstract

One,1-dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p'-DDE), the major metabolite of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p'-DDE exposure causes male reproductive toxicity remains unknown. To elucidate the mechanism underpinning the testicular effects of p,p'-DDE, we sought to investigate apoptotic effects and mRNA expression of apoptosis-associated genes in the testis of pubertal rats, including Fas, FasL, calpain-1, cytochrome c, Bax, Bcl-w, Bak, and caspase-3, -8, -9, -12. Animals were administered with different doses of p,p'-DDE (0, 20, 60, 100 mg/kg body weight) every other day by intraperitoneal injection for 10 days. The results indicated that p,p'-DDE exposure at over 20 mg/kg body weight showed the induction of apoptotic cell death. p,p'-DDE could induce decrease in SOD and GSH-Px activity of serum in 60 mg/kg body weight group. Significant elevations in the mRNA levels of Fas, FasL, calpain-1, cytochrome c, Bax, Bak, and caspase-3, -8, -9, -12 were observed in testis of rat treated with p,p'-DDE. Taken together, these results lead us to speculate that in vivo exposure to p,p'-DDE might induce testicular apoptosis in pubertal rats through the involvement of Fas/FasL, mitochondria and endoplasmic reticulum-mediated pathways. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:48 pm CET

Chromium(III) oxide nanoparticles induced remarkable oxidative stress and apoptosis on culture cells

Abstract

Chromium(III) oxide (Cr2O3) is used for industrial applications such as catalysts and pigments. In the classical form, namely the fine particle, Cr2O3 is insoluble and chemically stable. It is classified as a low-toxicity chromium compound. Recently, industrial application of nanoparticles (a new form composed of small particles with a diameter of ≤100 nm, in at least one dimension) has been increasing. Cellular effects induced by Cr2O3 nanoparticles are not known. To shed light upon this, the release of soluble chromium from Cr2O3 nano- and fine-particles in culture medium was compared. Fine Cr2O3 particles were insoluble in the culture medium; on the contrary, Cr2O3 nanoparticles released soluble hexavalent chromium into the culture medium. Cr2O3 nanoparticles showed severe cytotoxicity. The effect of Cr2O3 nanoparticles on cell viability was higher than that of fine particles. Cr2O3 nanoparticles showed cytotoxicity equal to that of hexavalent chromium (K2Cr2O7). Human lung carcinoma A549 cells and human keratinocyte HaCaT cells showed an increase in intracellular reactive oxygen species (ROS) level and activation of antioxidant defense systems on exposure to Cr2O3 nanoparticles. Exposure of Cr2O3 nanoparticles led to caspase-3 activation, showing that the decrease in cell viability by exposure to Cr2O3 nanoparticles was caused by apoptosis. Cellular responses were stronger in the Cr2O3 nanoparticles-exposed cells than in fine Cr2O3- and CrCl3-exposed cells. Cellular uptake of Cr2O3 particles were observed in nano- and fine-particles. The cellular influence of the extracellular soluble trivalent chromium was lower than that of Cr2O3 nanoparticles. Cr2O3 nanoparticles showed cytotoxicity by hexavalent chromium released at outside and inside of cells. The cellular influences of Cr2O3 nanoparticles matched those of hexavalent chromium. In conclusion, Cr2O3 nanoparticles have a high cytotoxic potential. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:48 pm CET

Signal pathway of hippocampal apoptosis and cognitive impairment of mice caused by cerium chloride

Abstract

Experimental studies have demonstrated that lanthanides could impair cognitive functions of children and animals, but very little is known about the hippocampal apoptosis and its molecular mechanism. The study investigated the signal pathway of hippocampal apoptosis induced by intragastric administration of CeCl3 for 60 consecutive days. It showed that cerium had been significantly accumulated in the mouse hippocampus, and CeCl3 caused hippocampal apoptosis and impairment of spatial recognition memory of mice. CeCl3 effectively activated caspase-3 and -9, inhibited Bcl-2, and increased the levels of Bax and cytochrome c, promoted accumulation of reactive oxygen species in the mouse hippocampus. It implied that CeCl3-induced apoptosis in the mouse hippocampus could be triggered via mitochondrion-mediated pathway. Our findings suggest the need for great caution to handle the lanthanides for workers and consumers. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:48 pm CET

Inflammatory cytokine gene expression in THP-1 cells exposed to Stachybotrys chartarum and Aspergillus versicolor

Abstract

Very little is known about the mechanisms that occur in human cells upon exposure to fungi as well as their mycotoxins. A better understanding of toxin-regulated gene expression would be helpful to identify safe levels of exposure and could eventually be the basis for establishing guidelines for remediation scenarios following a water intrusion event. In this research, cytokine mRNA expression patterns were investigated in the human monocytic THP-1 cell line exposed to fungal extracts of various fragment sizes obtained from Stachybotrys chartarum RTI 5802 and/or Aspergillus versicolor RTI 3843, two common and well-studied mycotoxin producing fungi. Cytokine mRNA expression was generally upregulated 2–10 times following a 24 h exposure to fungal extracts. Expression of the proinflammatory interleukin-1β, interleukin-8, and tumor necrosis factor-α genes increased while the anti-inflammatory gene interleukin-10 also increased albeit at very low level, suggesting that negative feedback regulation mechanism of production of proinflammatory cytokines initiated upon 24 h of incubation. In addition, submicron size extracts of A. versicolor caused significant death of THP-1 cells, whereas extracts of S. chartarum caused no cell death while the mixture of the two fungi had an intermediate effect. There was no general correlation between gene expression and fragment sizes, which suggests that all submicron fragments may contribute to inflammatory response. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:48 pm CET

In vitro toxicology of ambient particulate matter: Correlation of cellular effects with particle size and components

Abstract

High concentrations of airborne particulate matter (PM) have been associated with increased rates of morbidity and mortality among exposed populations. Although certain components of PM were suggested to influence these effects, no clear-cut correlation was determined thus far. One of the possible modes of action is the induction of oxidative stress by inhaled PM triggering inflammatory responses. Therefore, the in vitro formation of reactive oxygen species (ROS) in three cell lines in the presence of five subfractions of PM10, collected in Münster, Germany was investigated. The PM components chloride, nitrate, ammonium, sulfate, 68 chemical elements, and endotoxin were quantified. The highest concentration of endotoxin was found in particles of 0.42–1.2 μm aerodynamic diameters, and therefore probably subject to long-range transport. Intracellular ROS formation in three well established mammalian cell lines (CaCo2, human; MDCK, canine; RAW264.7, mouse) only correlated positively with particle size. The two smallest PM size fractions provoked the highest rise in ROS. However, the latter did not correlate with the concentration of any PM components investigated. The smallest PM size fractions significantly dominated the number of particles. Therefore, the particle number may be most effective in inducing oxidative stress in vitro. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:48 pm CET

Multiple biomarkers responses in juvenile rainbow trout, Oncorhynchus mykiss, after acute exposure to a fungicide propiconazole

Abstract

In this study, the toxic effects of propiconazole (PCZ), a triazole fungicide present in aquatic environment, were studied in juvenile rainbow trout, Oncorhynchus mykiss, by acute toxicity test with the concentration of 5.04 mg/L (96 h LC50). Morphological indices, hematological parameters, liver xenobiotic-metabolizing response, and tissue antioxidant status were evaluated. Compared with the control group, fish exposed to PCZ showed significantly higher Leuko, PCV, MCHC, and hepatic EROD, and significantly lower MCV. CF and HSI were not significantly different among groups. SOD, CAT, GPx, and GR activities increased significantly in liver of experimental groups, but decreased significantly in gill. In general, antioxidant enzyme activity in intestine was less evident than in liver. Oxidative stress indices (levels of LPO and CP) were significantly higher in gill. Additionally, through chemometrics of all parameters measured in this study, two groups with 67.29% of total accumulated variance were distinguished. In short, the physiological and biochemical responses in different tissues of fish indicated that PCZ-induced the stressful environmental conditions. But according to PCZ residual status in the natural environment, more long-term experiments at lower concentrations will be necessary in the future. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:48 pm CET

In vivo and in vitro liver and gill EROD activity in rainbow trout (Oncorhynchus mykiss) exposed to the beta-blocker propranolol

Abstract

The conservation of common physiological systems across vertebrate classes suggests the potential for certain pharmaceuticals, which have been detected in surface waters, to produce biological effects in nontarget vertebrates such as fish. However, previous studies assessing the effects of such compounds in fish have not taken into account the potential for metabolism and elimination. This study aimed to assess if propranolol, a β-adrenergic receptor antagonist or β-blocker, could modulate EROD activity (indicative of CYP1A activity) in rainbow trout (Oncorhynchus mykiss) gills and liver. For this, an in vivo time course exposure with 1 mg/L was conducted. Additionally, using measured in vivo plasma concentrations, an in vitro exposure at human therapeutic levels was undertaken. This allowed comparison of in vitro and in vivo rates of EROD activity, thus investigating the applicability of cell preparations as surrogates for whole animal enzyme activity analysis. In vitro exposure of suspended liver and gill cells at concentrations similar to in vivo levels resulted in EROD activity in both tissues, but with significantly higher rates (up to six times in vivo levels). These results show that propranolol exposure elevated EROD activity in the liver and gill of rainbow trout, and that this is demonstrable both in vivo (albeit nonsignificantly in the liver) and in vitro, thus supporting the use of the latter as a surrogate of the former. These data also provide an insight into the potential role of the gill as a site of metabolism of pharmaceuticals in trout, suggesting that propranolol (and feasibly other pharmaceuticals) may undergo “first pass†metabolism in this organ. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 7 Mar 2011 | 2:11 pm CET

Toxic effects of chromium (VI) by maternal ingestion on liver function of female rats and their suckling pups

Abstract

Potassium dichromate (K2Cr2O7) is an environmental contaminant widely recognized as a carcinogen, mutagen, and teratogen toward humans and animals. This study investigated the effects of K2Cr2O7 on the hepatic function of pregnant and lactating rats and their suckling pups. Experiments were carried out on female Wistar rats given 700 ppm of K2Cr2O7 in their drinking water from the 14th day of pregnancy until day 14 after delivery. Hepatotoxicity was objectified by the significant increase in liver malondialdehyde content and a significant accumulation of chromium in this soft tissue. Moreover, exposure to K2Cr2O7 induced a decrease of glutathione, nonprotein thiols, and vitamin C in the liver of mothers and their suckling pups. Alteration of the antioxidant system in the treated group was confirmed by the significant decline of antioxidant enzyme activities such as catalase, glutathione peroxidase, while liver superoxide dismutase activity increased in mothers and decreased in their offspring. It was found that K2Cr2O7 induced liver damages as evidenced by the elevation of plasma aminotransferases, lactate dehydrogenase activities, and bilirubin levels. Impairment of the hepatic function corresponded histologically. Our investigation revealed hemorrhage, leukocytes infiltration cells, and necrosis, which were more pronounced in the hepatocytes of mothers than in those of their suckling pups. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 5:01 pm CET

Oxidative stress in ventral prostate, ovary, and breast by 2,4-dichlorophenoxyacetic acid in pre- and postnatal exposed rats

Abstract

The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been widely used in agriculture and forestry since the 1940s. 2,4-D has been shown to produce a wide range of adverse effects—from embryotoxicity and teratogenicity to neurotoxicity—on animal and human health. The purpose of this study was to determine the possible effects of pre- and postnatal exposure to 2,4-D on oxidative stress in ventral prostate, ovary and breast. Pregnant rats were daily exposed to oral doses of 70 mg/kg/day of 2,4-D from 16 days of gestation up to 23 days after delivery. Then, the pups were sacrificed by decapitation at postnatal day (PND) 45, 60, or 90. Antioxidant enzyme activities and some parameters of the oxidative stress were assessed in ventral prostate, breast, and ovary. Results show that 2,4-D produced three different effects. First, it increased the concentration of some radical oxygen species and the rates of lipid peroxidation and protein oxidation in ventral prostate, thereby causing oxidative stress at all ages studied. Although an increase in the activity of some antioxidant enzymes was detected, this seemed to have been not enough to counteract the oxidative stress. Second, 2,4-D promoted the oxidative stress in the breasts, mainly during puberty and adulthood, probably because the developing gland is more sensitive to xenobiotics than the adult organ. Third, 2,4-D altered the activity of some antioxidant enzymes and increased lipid peroxide concentration in the ovary. This effect could reflect the variety of ovarian cell types and their different responses to endocrine changes during development. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 5:01 pm CET

Necrosis and apoptosis of renal tubular epithelial cells in rats exposed to 3-methyl-4-nitrophenol

Abstract

The 3-methyl-4-nitrophenol (4-nitro-m-cresol; PNMC) exists in diesel exhaust particles (DEP), and is also one of the degradation products of insecticide fenitrothion. To assess potential nephrotoxicity of PNMC, male Sprague-Dawley (SD) rats were subcutaneously dosed with PNMC at 1, 10, and 100 mg/kg/day for five consecutive days. No significant changes were detected in body weights and relative weights of kidneys by the treatment of PNMC. However, the extent of cellular necrosis was found to be severe in renal tubular epithelial cells of PNMC-treated rats. In addition, PNMC exposure significantly increased the number of terminal deoxynucleotidyle transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells compared to the control in renal tubule of PNMC-treated rats. Moreover, immunohistochemical results indicated that significant decrease in the B-cell lymphoma 2 (Bcl-2) expressions andincrease in the Bcl-2 associated × protein (Bax) expression were detected in PNMC-treated rats. The ratio of Bcl-2/Bax was also reduced significantly at PNMC-treated rats dosed at 10 or 100 mg kg−1. Furthermore, the significant increase of FAS (CD95/APO-1) expression was found in the groups dosed at 10 or 100 mg kg−1 of PNMC. The expression of Caspase-3 was higher in PNMC-treated rats, compared to the control group. Our results indicated that activation of mitochondria and Caspase-3 protease may contribute to the PNMC-induced apoptosis, suggesting that PNMC could cause both necrosis and apoptosis resulting in cell death of renal epithelium cells and could induce renal toxicity. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 5:01 pm CET

Ecotoxicological effects of Mikado® and Viper® on algae and daphnids

Abstract

The toxicity of single and combined formulated herbicides (Mikado® and Viper®) was assessed on several endpoints in species from two trophic levels: algae growth—Pseudokirchneriella subcapitata and Chlorella vulgaris—immobilization and life-history traits (only for single compound toxicity) of daphnids—Daphnia longispina and Daphnia magna. Viper was the most toxic formulated herbicide. It was hypothesized that the toxicity of both formulated herbicides could have been enhanced by adjuvants, especially for Viper. In most cases, the sublethal endpoints were the most sensitive and affected by both formulations, comparatively to their acute effects. Concentration addition (CA) and independent action (IA) models provided an accurate description of Mikado and Viper joint action on algae growth and immobilization of daphnids, although significant deviations were always detected. A low-dose antagonism and high-dose synergism were identified for P. subcapitata, whereas C. vulgaris response deviated antagonistically from CA and synergistically from IA. For both daphnids, however, synergistic effects were observed for higher mixture concentrations. Under a regulatory standpoint, CA provided the most conservative estimation either because the mixture effects were overestimated or less subestimated than IA. Overall, the great sensitivity differences observed within species did not allow the conclusion that one trophic level was more tolerant than the other. Instead, P. subcapitata was always the most sensitive species to both herbicide formulations, followed by D. longispina, while D. magna and C. vulgaris were the most tolerant species. On a whole, further studies are needed toward a comprehensive understanding of herbicides mode of action, their effects at lower biological-level endpoints, and under different mixture designs. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 5:01 pm CET

Physiological responses of three marine microalgae exposed to cypermethrin

Abstract

The effects of cypermethrin on physiological responses of three typical marine microalgal species Skeletonema costatum (Bacillariophyceae), Scrippsiella trochoidea (Dinophyceae), and Chattonella marina (Raphidophyceae), were investigated by 96-h growth tests in a batch-culture system. The 96-h median inhibition concentrations (IC50) were 71.4, 205, and 191 μg L−1 for S. costatum, S. trochoidea, and C. marina, respectively. Quick and significant physiological responses occurred when algal cells were exposed to cypermethrin, and all biochemical parameters varied significantly within 6- or 12-h exposure. Cypermethrin affected algal growth, protein content, and superoxide dismutase (SOD) activity by stimulation at low concentrations (1, 5 μg L−1) and inhibition at high concentrations (>50 μg L−1). A general increase in malondialdehyde (MDA) level was observed in all test groups, which suggested that the toxic effects of cypermethrin were probably exerted through free radical generation. These results suggest that the activation of SOD and promotion of protein at early exposure are important to counteract the oxidative stress induced by cypermethrin, and the inactivation of SOD may be crucial to the growth inhibition of microalgae by cypermethrin. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 5:01 pm CET

Effects of bioreactive acrolein from automotive exhaust gases on human cells in vitro

Abstract

Acrolein is a toxic unsaturated aldehyde and widespread environmental pollutant produced during lipid peroxidation and also by burning of tobacco or liquid fuels. Inhalation or dermal exposure to acrolein could be toxic to organisms. This very reactive aldehyde has a strong affinity for binding to proteins thus forming pathogenic protein-adducts. In the present study we have analyzed formation of bioreactive acrolein-protein adducts in bovine serum albumin solution exposed to exhaust gases of mineral diesel fuel and of mineral diesel fuel supplemented with different amounts of a novel diesel fuel additive denoted Ecodiesel (produced by a genuine procedure of recycling of plant oils used for food preparation). The effects of acrolein-protein adducts were tested on human microvascular endothelial cells and on human osteosarcoma cells that are sensitive to bioactivities of lipid peroxidation products. The results have shown a reduction of the bioreactive acrolein in exhaust gases when mineral diesel was supplemented with 5–20% Ecodiesel. Moreover, acrolein-protein adducts obtained from mineral diesel supplemented with Ecodiesel were less toxic than those obtained from mineral diesel alone. Thus, we assume that supplementing mineral diesel fuel with Ecodiesel would be of benefit for the use of renewable energy, for environment and for human health due to reduced environmental pollution with bioreactive acrolein. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 5:00 pm CET

Physiological, anatomical, biochemical, and cytogenetic effects of thiamethoxam treatment on Allium cepa (amaryllidaceae) L.

Abstract

n the present study, toxic effects of active substance thiamethoxam of the insecticide Eforia were investigated on Allium cepa L. For this aim, we used the germination percentage, root length, weight gain, malondialdehyde (MDA) level, frequency of micronucleus (MN), chromosomal aberrations (CAs), and mitotic index (MI) as indicators of toxicity. Also, the changes in the root anatomy of A. cepa seeds treated with thiamethoxam were examined. The seeds in all the treatment groups were treated with three different doses (100, 250, and 500 mg/kg) of thiamethoxam for 72 h. The results showed that there were significant alterations in the germination percentage, root length, weight gain, MDA level, MN, CAs, and MI frequency depending on application dose in the seeds exposed to thiamethoxam compared to control group. Thiamethoxam treatments significantly reduced the germination percentage, root length, and weight gain in all the treatment groups (P < 0.05). But, it caused an increase in MN and CAs formation (P < 0.05). It was also found that thiamethoxam has a mito-depressive action on mitosis, and the MI was decreased depending on the dose of applied-thiamethoxam (P < 0.05). About 100, 250, and 500 mg/kg doses of thiamethoxam significantly enhanced the lipid peroxidation and caused an increase in MDA levels at each dose treatment (P < 0.05). Some anatomical damages such as necrotic cell death, unclear vascular tissue, unclear epidermis layer, cell deformation, and unusual form of cell nucleus were observed by using light micrographs. Each dose of thiamethoxam caused severe toxic effects on A. cepa cells, and the maximum toxic effect was observed at the dose level of 500 mg/kg. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 5:00 pm CET

Acute and chronic toxicity of Betanal®Expert and its active ingredients on nontarget aquatic organisms from different trophic levels

Abstract

As a way to improve the efficacy to target organisms, new pesticide generation is based on technologically advanced coformulations of two or more active ingredients. One example is Betanal®Expert, a postemergence herbicide composed of an Advanced Micro Droplet coformulation of phenmedipham, desmedipham, and ethofumesate. Although its composed formulation brings an increase in the pesticide performance, it can also enhance its toxicity to nontarget species. Therefore, the present study intends to contribute with relevant information on ecotoxicological effects of Betanal®Expert and its active ingredients on a battery of bioassays using aquatic species from different trophic levels: bacteria (Vibriofischeri), microalgae (Pseudokirchneriella subcapitata, Chlorella vulgaris, and Chlamydomonas pseudocostata), macrophyte (Lemna minor), and cladocerans (Daphnia magna and Daphnia longispina) species. Across the organisms tested and endpoints measured, different responses concerning the toxicity of the active ingredients were found: (i) phenmedipham was the most toxic to V. fischeri and L. minor; (ii) desmedipham was the most toxic to P. subcapitata, D. magna, and D. longispina; (iii) and ethofumesate was the most toxic to C. pseudocostata and C. vulgaris. Furthermore, for C. pseudocostata and daphnids, the toxicity observed for some active ingredients was higher than the toxicity of the commercial formulation. In fact, in an attempt to evaluate the contribution of each active ingredient to the overall toxicity of Betanal®Expert, it was observed that, in general, the toxicity values obtained for desmedipham and phenmedipham were close or even lower to the values determined for Betanal®Expert, indicating that the ethofumesate can act as an antagonist in the three-way coformulation. In spite of the most impaired species being the photosynthetic ones, this study also showed pernicious effects on nonphotosynthetic organisms with distinct target sites. Therefore, our results underline the importance of clarifying the mode of action and metabolic pathways of these compounds on nonphotosynthetic species. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 4:59 pm CET

Mercury transfer in a subtropical coastal lagoon food web (SE Gulf of California) under two contrasting climatic conditions

Abstract

Mercury (Hg) transference through an established and defined food web from an urbanized subtropical coastal lagoon (SE Gulf of California) was examined by using carbon and nitrogen stable isotope and Hg analyses. Concentrations of Hg in seawater (0.045–0.078 μg L−1), predominantly incorporated to the particulate fraction (60% of total), were lower than those found in highly contaminated coastal areas around the world (0.18–16 μg L−1). Although levels of Hg available for the biota (e.g., associated to the reactive and pyrite fractions; 0.11–0.15 μg g−1) were within of effects range-low (ER-L, 0.15–0.71 μg g−1) these concentrations represented from 46.6 to 67.0% of the total Hg pool that may be transferred through food web. The sequence of bio-accumulation of Hg in studied species was according with their functional guild: tertiary consumer (0.85–1.15 μg g−1) > secondary consumers (0.084–0.168 μg g−1) > primary consumers (0.014–0.160 μg g−1) > primary producers (0.016–0.056 μg g−1). Hg concentrations increased for each successive trophic position estimate through δ15N isotopic values, although these relationships showed differences between dry and rainy seasons (R2 = 0.37 and R2 = 0.39 between δ15N vs. Hg in organisms, respectively). We concluded that Hg is being positively transferred (biomagnification factor >1) through the studied food web probably enhanced by the favorable environmental conditions for Hg-methylation (e.g., fine sediments rich in organic matter, and environmental conditions changes of the redox, pH, and temperature) found in this urbanized coastal water, however, the study of processes methlylation and biomagnifcation of Hg need further investigations. © 2011Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 3 Mar 2011 | 4:59 pm CET

Effects of cypermethrin on Allium cepa

Abstract

In this study, toxic effects of the cypermethrin in Allium cepa L. cells were investigated. For this aim, we investigated the changes in pigment contents, antioxidant enzymes, mitotic index and chromosomal abnormalities as indicators of toxicity. The seeds were treated with different doses (1.5, 3.0, 6.0 ppm) of cypermethrin for 72 h. The result showed that there was a significant alteration in the tested parameters depending on treatment dose in the seeds exposed to cypermethrin when compared to the control group. Cypermethrin exposure significantly reduced the carotenoid, chlorophyll a and b pigments in all treatment groups. The activity of superoxide dismutase showed a concentration-time dependent increase and the maximum increase was observed on day 15 of treatment at 6.0 ppm cypermethrin exposure. The activity of catalase increased gradually with increasing cypermethrin concentration, but a soft decrease in CAT activity was decreased after 15 days of 1.5 ppm and 3.0 ppm cypermethrin treatment. In the roots treated with 1.5, 3.0, and 6.0 ppm cypermethrin, the level of malondialdehyde was about 1.8, 2.4, and 3.4 times higher than the control group, respectively. It was also found that cypermethrin has a mitodepressive action on mitosis, and the MI was decreased depending on the dose of cyprmethrin. All of the concentrations of cypermethrin induced chromosomal abnormalities and the most common abnormality observed in the present study was chromosome bridges. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2011.

Quelle: Environmental Toxicology | 2 Mar 2011 | 7:58 pm CET

In utero and lactational exposure to PCB 118 and PCB 153 alter ovarian follicular dynamics and GnRH-induced luteinizing hormone secretion in female lambs

Abstract

The effects of in utero and lactational exposure to two structurally different polychlorinated biphenyl (PCB) congeners on follicular dynamics and the pituitary-gonadal axis in female lambs were investigated. Pregnant ewes received corn oil, PCB 118, or PCB 153, and offspring was maintained until 60 days postpartum. Ovarian follicles were quantified using stereology. Plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured using radioimmunoassay before and after administration of a gonadotropin releasing hormone (GnRH) analog. PCB 118 exposure increased numbers of transitional, secondary, and the sum of secondary, early antral, and antral (Σsecondary-antral) follicles, PCB 153 exposure only increased the number of primary follicles. GnRH-induced LH levels were significantly elevated in the PCB 153 exposure group. We conclude that PCB 153 and PCB 118 alter follicular dynamics in lambs and modulate the responsiveness of the pituitary gland to GnRH. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 22 Feb 2011 | 6:07 pm CET

Aryl hydrocarbon receptor-independent up-regulation of intracellular calcium concentration by environmental polycyclic aromatic hydrocarbons in human endothelial HMEC-1 cells

Abstract

Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (B(a)P) constitute a major family of widely-distributed environmental toxic contaminants, known as potent ligands of the aryl hydrocarbon receptor (AhR). B(a)P has been recently shown to trigger an early and transient increase of intracellular calcium concentration ([Ca2+]i), involved in AhR-related up-regulation of target genes by B(a)P. This study was designed to determine whether AhR may play a role in [Ca2+]i induction provoked by B(a)P. We demonstrated that, in addition to B(a)P, various PAHs, including pyrene and benzo(e)pyrene, known to not or only very poorly interact with AhR, similarly up-regulated [Ca2+]i in human endothelial HMEC-1 cells. Moreover, α-naphthoflavone, a flavonoïd antagonist of AhR, was also able to induce [Ca2+]i. Knocking-down AhR expression in HMEC-1 cells through transfection of siRNAs, was finally demonstrated to not prevent B(a)P-mediated induction of [Ca2+]i, whereas it efficiently counteracted B(a)P-mediated induction of the referent AhR target gene cytochrome P-450 1B1. Taken together, these data demonstrate that environmental PAHs trigger [Ca2+]i induction in an AhR-independent manner. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 22 Feb 2011 | 6:07 pm CET

Peripheral DNA damage in active pulmonary tuberculosis

Abstract

In pulmonary tuberculosis patients, little is known about peripheral DNA damage, although increased oxidative stress is a well documented entity. Therefore, we aimed to investigate DNA damage along with oxidative status parameters in pulmonary tuberculosis patients. Twenty-seven pulmonary tuberculosis patients and 26 controls were included. DNA damage was assessed by comet assay. Total oxidant and antioxidant status, and oxidative stress index were determined. DNA damage, total oxidant status and oxidative stress index were higher in pulmonary tuberculosis patients than controls (all P < 0.05), while total antioxidant status was lower (P < 0.05). DNA damage was correlated with total oxidant and antioxidant status, and oxidative stress index (r = 0.69, P < 0.05; r = 0.48, P < 0.05, r = −0.47, P < 0.05; respectively) in pulmonary tuberculosis patients. Oxidative stress and DNA damage are increased in pulmonary tuberculosis patients. Increased oxidative stress associated DNA damage may be one of the pathogenetic mechanisms involved in the disorders suggested to be associated with pulmonary tuberculosis. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 22 Feb 2011 | 6:06 pm CET

Induction of oxidative stress in liver and kidney of rats exposed to Nigerian bonny light crude oil

Abstract

The local population of Niger-Delta in the Southern part of Nigeria have used bonny light crude oil (BLCO) as a remedy for various ailments and are exposed to some extent to this widespread environmental contaminant or its metabolites through the food chain. BLCO's hepatorenal toxicity was studied using oxidative stress indices to elucidate the precise nature and mechanism of action. BLCO was orally administered at concentrations of 0, 200, 400, and 800 mg kg−1 to adult male rats for 7 days. After exposure, kidney weight was unaffected, but liver weight decreased significantly at 800 mg kg−1 only compared with control. BLCO exposure resulted in dose-dependent elevation of serum aminotransferases, total bilirubin, urea, and creatinine. Activities of superoxide dismutase and catalase decreased significantly, whereas γ-glutamyltransferase activity and the level of glutathione increased significantly in BLCO-treated animals compared with control in both liver and kidney of rat. Renal activities of glucose-6-phosphatase and 5′-nucleotidase markedly decreased in a dose-dependent manner in BLCO-exposed rats. In addition, the levels of hydrogen peroxide and lipid peroxidation significantly increased, dose dependently, in liver and kidney of BLCO-treated rats compared with control. BLCO-treated rats showed marked degeneration of kidney evident in cortical hemorrhages, tubular necrosis, protein casts, and cellular infiltration. However, no treatment-related liver histopathology was observed. The results suggested that BLCO elicits disruption of antioxidant status and concomitant elevation of hydrogen peroxide and lipid peroxidation differentially in liver and kidney of rats. The hepatorenal toxicity of BLCO could be due to induction of oxidative stress in liver and kidney. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 9 Feb 2011 | 9:10 pm CET

Oxidative damage and OGG1 expression induced by a combined effect of titanium dioxide nanoparticles and lead acetate in human hepatocytes

Abstract

Titanium dioxide (TiO2) is a widely used nanomaterial that can cause biological damage through oxidative stress. At low concentrations, TiO2 can interact with lead acetate (PbAc) to produce different toxic responses, compared with TiO2 or PbAc alone. In this study, we utilized the following as indicators of toxic responses in human embryo hepatocytes (L02): reactive oxygen species (ROS), reduced glutathione (GSH), superoxide dismutase (SOD), and the DNA adducts 8-hydroxydeoxyguanosine (8-OHdG) and 8-oxoguanine DNA glycosylase homolog 1 (OGG1). These were used to evaluate the oxidative stress of TiO2 (at 0.001, 0.01, 0.1, 1, and 10 μg mL−1) mixed with PbAc (1 μg mL−1) on L02 cells without photoactivation. Compared with the negative control (1‰ dimethyl sulfoxide), TiO2 mixed with PbAc induced increased release of ROS (at 0.001, 0.01, 0.1, 1, 10 μg mL−1 TiO2), intracellular SOD activity (at 0.1 and 0.01 μg mL−1 TiO2), GSH levels (at 0.01–1 μg mL−1 TiO2), 8-OHdG levels (at 1 and 10 μg mL−1 TiO2), OGG1 expression (at 0.001–1 μg mL−1 TiO2), and cytotoxicity (at 0.1, 1, and 10 μg mL−1 TiO2) in L02 cells. There were no significant changes in ROS, GSH, SOD, 8-OHdG, or OGG1 levels when L02 cells were treated with TiO2 alone or PbAc alone. These findings indicate that TiO2 and PbAc in combination induce cytotoxicity and oxidative stress in L02 cells in the absence of photoactivation. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 20 Jan 2011 | 10:16 pm CET

Low-dose methylmercury-induced oxidative stress, cytotoxicity, and tau-hyperphosphorylation in human neuroblastoma (SH-SY5Y) cells

Abstract

Acute neurotoxic effects of high-dose methylmercury (MeHg) in humans have been well documented in the scientific literature. However, low-dose effects are less well described. This study was designed to evaluate the effects of low-dose MeHg (<100 nM) on human brain cells in a tissue culture model. Neuroblastoma (NB) cells (SH-SY5Y) were used in the cell culture model to study low-dose effects of MeHg on cell growth, cell survival, reactive oxygen species (ROS), and the phosphorylation of tau protein, as a measure of potential markers of cellular events associated with tauopathies. When cells were incubated in culture with MeHg (50 and 100 nM), there were significant decreases in cell viability as well as significant increase in ROS generation as determined by fluorescent dye analysis (H2DCFDA). Furthermore, a concomitant decrease in glutathione levels to 25% of control was observed at both 50 and 100 nM MeHg. In addition, the level of phosphorylated tau was significantly increased after treatment at both 50 and 100 nM MeHg, compared with controls. Pretreatment of NB cells with the antioxidant, N-acetylcysteine (1.25 mM) and the calpain inhibitor, MDL-28170 (10 μM), significantly attenuated the effects of MeHg (50 and 100 nM) on cell viability as well as on tau phosphorylation. These results indicate that low-dose MeHg toxicity may be related to an induction of tau phosphorylation through an oxidative stress-dependent mechanism and that blockade of this pathway may attenuate the toxic effects of MeHg. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 20 Jan 2011 | 10:15 pm CET

Toxicity of food contaminant furan on liver and kidney of growing male rats

Abstract

Furan is a chemical used in some industrial products and occurs naturally in heat-treated foods. We aimed to investigate the effects of orally administered furan on liver and kidney in growing Wistar male rats for 90 days. In this respect, biochemical, morphological, histopathological, and histomorphometrical examinations were performed. Three- to 4-week aged rats were divided into five groups of eight animals each; control, oil control; 2, 4, 8 mg/kg/day furan treatment groups. At the end of the experiment, antioxidant enzyme activities and serum AST, ALT, HDL, Urea, etc. levels were analyzed. Malondialdehyde (MDA) levels, superoxide dismutase (SOD), catalase (CAT), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were also measured in liver homogenates. Also, liver and kidney were examined morphologically and histopathologically under light microscopy. According to the results of biochemical analysis, ALT, ALP, and LDL levels in treatment groups were significantly different compared with control groups. While LDL levels in treatment groups increased significantly, ALT and ALP levels decreased significantly. No significant changes were observed in liver MDA levels, superoxide dismutase and catalase activities in treatment groups. While IL-6 levels did not change in treatment groups, furan caused dose-dependent increases in liver TNF-α level of rats. In treatment groups, absolute and relative liver weights changed significantly, however, no significant changes were observed in kidney and relative kidney weights. Hyperemic blood vessels in the liver and congestion, edema, fibrosis, and tubular damage in the kidney of rats treated with furan were observed histopathologically. According to histomorphometric examinations, glomeruli diameters and glomerular volume decreased in the kidneys of rats in treatment groups. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 20 Jan 2011 | 10:15 pm CET

Rutin inhibits human leukemia tumor growth in a murine xenograft model in vivo

Abstract

Numerous studies have shown that rutin has anticancer effects. We have previously reported that rutin induced cell cycle arrest and apoptosis in murine leukemia WEHI-3 cells in vitro and in vivo. However, there are no data showing that rutin inhibits human leukemia HL-60 cells in vivo in a murine xenograft animal model. Human leukemia HL-60 cells were implanted into mice and treated with vehicle (1% DMSO), rutin (120 mg/kg of body weight) or vinblastine (120 μg/kg of body weight). Compounds and agents were injected once every four days intraperitoneally (i.p.) for 36 days. Treatment with 120 mg/kg of rutin or with 120 μg/kg of vinblastine resulted in a reduction of tumor weight and volume when compared with the control groups. Tumor size in xenograft mice treated with 120 mg/kg of rutin was significantly smaller than that in the untreated-control group. These novel findings indicate that rutin inhibits tumor growth in a xenograft animal model. Rutin may be useful in treating leukemia but certainly much more research is needed. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Quelle: Environmental Toxicology | 20 Jan 2011 | 10:15 pm CET

Antiapoptotic efficacy of folic acid and vitamin B12 against arsenic-induced toxicity

Abstract

Earlier, we proposed that the ability of folic acid and vitamin B12 to preserve systemic and mitochondrial function after short-term exposure to arsenic may prevent further progression to more permanent injury and pathological changes leading to cell death. To elucidate its mechanism, the present study examined the antiapoptotic efficacy of folic acid and vitamin B12 against short-term arsenic exposure-induced hepatic mitochondria oxidative stress and dysfunction. Sixteen to eighteen weeks old male albino rats weighing 140–150 × g were divided into five groups: Control (A), Arsenic-treated (B), Arsenic + folic acid (C), Arsenic +vitamin B12 (D), and Arsenic + folic acid + vitamin B12 (E). Data generated indicated that folic acid and vitamin B12 separately or in combination can give significant protection against alterations in oxidative stress and apoptotic marker parameters and downstream changes in mitochondria, namely pro-oxidative (NO, TBARS, OH−) and antioxidative defense (SOD, CAT, GSH) markers, iNOS protein expression, mitochondrial swelling, cytochrome c oxidase and Ca2+-ATPase activity, Ca2+ content, caspase-3 activity. Additionally, results of hepatic cell DNA fragmentation, arsenic load of blood, hepatic tissue and urine, and histological observations, all strongly support that both these supplements have efficacy in preventing apoptotic changes and cellular damage. As the mechanisms of actions of both of these supplements are methylation related, a combined application was more effective. Results further reveal new molecular targets through which folic acid and vitamin B12 separately or in combination work to alleviate one critical component of arsenic-induced liver injury: mitochondria dysfunction. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 8 Dec 2010 | 3:50 pm CET

Biochemical and genotoxic effect of triclosan on earthworms (Eisenia fetida) using contact and soil tests

Abstract

Triclosan (TCS) is a broad-spectrum bactericide that is used for a variety of antimicrobial functions. TCS is frequently detected in the terrestrial environment due to application of sewage sludge to agricultural land. In the present study, 48-h paper contact and 28-day spiked soil tests were conducted to examine the toxic effects of TCS on the antioxidative and genetic indices of earthworms (Eisenia fetida). The activity of antioxidative enzymes (superoxide dismutase, SOD; catalase, CAT) and the content of the lipid peroxidation product (malondialdehyde, MDA) were determined as biomarkers of oxidative stress in E. fetida. Moreover, single cell gel electrophoresis (SCGE) was used as a biomarker of genotoxicity. The results showed that triclosan induced a significant increase (P < 0.05) in antioxidative enzyme activities and MDA content. Of all of the biomarkers examined, CAT activity was most sensitive to TCS, and the CAT activity increased significantly (P < 0.05) at bactericidal concentrations of 7.86 ng cm−2 in the contact test and 10 mg kg−1 in the spiked soil test. The comet assay showed that TCS treatments significantly induced (P < 0.05) DNA damage in E. fetida, and that 78.6 ng cm−2 caused significant genotoxic effects in the acute test (48 h). Clear dose-dependent DNA damage to E. fetida was observed both in contact and spiked soil tests. These results imply that TCS may have potential biochemical and genetic toxicity toward earthworms (E. fetida). A battery of biomarkers covering multiple molecular targets of acute toxicity can be combined to better understand the impacts of TCS on E. fetida. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 8 Dec 2010 | 3:50 pm CET

Antioxidant enzyme activities and lipid peroxidation in earthworm Eisenia fetida exposed to 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-γ-2-benzopyran

Abstract

Polycyclic musks have been indicated to cause lethal and sublethal effects on exposed biota. However, knowledge about the effect of polycyclic musks on the antioxidant defense system in earthworms is vague. In this work, the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) exposed to 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-γ-2-benzopyran (HHCB) were systematically investigated. The investigation shows that their activities are closely related to the exposed dose and time of HHCB. For SOD and CAT, the activities increased monotonically with increased exposed dose of HHCB, which indicates a dose-dependent change pattern. POD exhibited its peak activity in 0.0157 μg cm−2 HHCB treatment and decreased at higher concentrations. These two changing patterns were complementary, which reveals the cooperation of enzymes in response to oxidative stress. MDA content in earthworms was basically unaffected with a 1-day exposure and significantly increased after 2-day and 3-day exposures, correlating with changes in the activities of SOD and CAT when the concentration of HHCB was high. It was also found that the sensitivity of Eisenia fetida to HHCB increased over time. These results may support the theoretical hypothesis that oxidative stress is an important component for the response of earthworms to the toxicity of HHCB in environment. Among the studied enzymes, SOD and CAT appeared to be the most responsive biomarkers of oxidative stress caused by HHCB. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 8 Dec 2010 | 3:50 pm CET

Effect of sublethal hexavalent chromium exposure on the pituitary-ovarian axis of a teleost, Channa punctatus (Bloch)

Abstract

Exposure to sublethal hexavalent chromium (as 2 and 4 mg L−1 potassium dichromate for 1 and 2 months) during late preparatory to mid prespawning phase of annual reproductive cycle severely affected the pituitary-ovarian axis of a teleost Channa punctatus. Gonadosomatic index (GSI), ovarian histopathology, immunocytochemistry of the pituitary gonadotrophs (LHβ-immunoreactive cells), and serum 17β-estradiol level revealed distinct dose and duration-dependent effects. Gonadosomatic index was declined. Diameter of ovary as well as ovarian follicles was reduced along with a distinct variation in the percentage of follicles. The greater percentage of previtellogenic follicles (stage I) and decline in vitellogenic ones (stage II and stage III) compared to control indicated the arrest of follicular development. The percentage of atretic follicles was also increased indicating toxic impact of metal on ovary. Decreased serum level of ovarian steroid 17β-estradiol further indicated the same. Chromium interference of the pituitary was demonstrated as atrophy and less immunointensity of LH-immunoreactive gonadotrophs. Thus, the hexavalent chromium impaired the pituitary-ovarian axis affecting at the sites of both pituitary and ovary. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:38 pm CET

Effect of agropesticides use on male reproductive function: A study on farmers in Djutitsa (Cameroon)

Abstract

This study aimed at investigating the effect of agropesticides on male reproductive function in farmers in Djutitsa (West Cameroon). To this end, 47 farmers in Djutitsa were asked questions on their health status and pesticide use in agriculture. Thereafter, their blood samples were collected for assessment of sex hormones including serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), androstenedione, testosterone, as well as sex hormone binding globulin (SHBG). Their serum triiodothyronine (T3) and thyroxine (T4) levels were also measured. Thirty seven men not exposed to agropesticides were recruited as control group. Fifty six pesticides containing 25 active substances were currently used by farmers enrolled in our study, and most of their symptoms were related to spread/use of these chemicals. Compared to the control group, there was no significant difference in FSH, LH, SHBG, estradiol, and thyroid hormones (T3 and T4) levels. Farmers had significantly lower serum testosterone (20.93 ± 1.03 nM vs. 24.32 ± 1.32 nM; P < 0.05) and higher androstenedione level (3.83 ± 0.20 nM vs. 2.80 ± 0.15 nM; P < 0.001). Their serum free testosterone as well as bioavailable testosterone were unchanged, while estradiol/testosterone and androstenedione/testosterone ratios were significantly increased (0.45 ± 0.03% vs. 0.33 ± 0.02%; P < 0.01 and 12.26 ± 3.64 vs 19.31 ± 6.82; P < 0.001, respectively). Our results suggest that male farmers of Djutitsa (West Cameroon) are exposed to agropesticides due to improper protective tool, and this exposure may impair their reproductive function through inhibition of testosterone synthesis; probably by inhibition of testicular 17β- hydroxysteroid dehydrogenase (17HSD3) and induction of aromatase (CYP19). © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:38 pm CET

Microcystin-producing genotypes from cyanobacteria in Brazilian reservoirs

Abstract

The aim of this study was to evaluate the use of new oligonucleotide primers (mcyB-F/R, mcyB-F/R-A, and mcyB-F/R-B) designed from Brazilian cyanobacteria for the detection of microcystin-producing genotypes in 27 environmental samples from water reservoirs and 11 strains of Microcystis. Microcystins were found using HPLC in all 11 strains and 19 of the environmental samples. The new oligonucleotide primers amplified fragments of microcystin-producing genes, including the eight environmental samples in which no microcystins were detected by HPLC, but which presented amplified fragments, thereby demonstrating the existence of microcystin-producing genes. The new oligonucleotide primers exhibited better specificity when used with environmental samples and were more reliable in comparison with those described in the literature (mcyB-FAA/RAA and mcyA-Cd/FR), which generate false-negative results. The better performance of these new oligonucleotide primers underline the need for designing molecular markers that are well fitted to the regional biological diversity. As this is a fast predictive technique for determining the presence or absence of microcystins, it could be used either alone or in conjunction with other techniques, such as the screening of samples to be sent for quantitative toxicological analysis using HPLC, thereby reducing monitoring cost and time. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:38 pm CET

Main partitioning criteria for the characterization of the health status in the freshwater mussel Anodonta cygnea from spontaneously polluted area in western ukraine

Abstract

The aim of this study was to appreciate the consequences of spontaneous human activity for freshwater mollusks in the generally ecologically sustainable area in Western Ukraine. For this, bivalve mollusk, Anodonta cygnea, at three sites, with mixed agricultural and municipal activities (A), close to a municipal water inlet (F) and the cooling pond of a nuclear power plant (N), were studied in spring, summer, and autumn. The set of parameters included the characteristics of oxidative stress (activity of catalase (CAT), levels of protein carbonyls (PC)), levels of reduced and oxidized glutathione (GSH, GSSG, respectively), activities of lactate dehydrogenase (LD), cholinesterase (ChE), ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST) in the digestive gland, and concentrations of vitellogenin-like proteins (Vtg-LP) in gonads and also morphological indices. Although the discriminant functional analysis confirmed the general seasonal regularities for studied groups, it allowed to discriminate between sites (P < 0.05). At site A, oxidative stress; high levels of LD, EROD, and GST; and low levels of ChE and condition factor were reflected. This demonstrated the sensitivity of mussels to constant effect of mixed pollution. At site N, oxidative injury was shown that might be explained by the constantly high temperature. At site F, abrupt elevations of Vtg-LP and EROD levels in autumn were probably related to an emergency situation on the nearby dump. So, both chronic and temporal environmental effects were reflected by a set of markers in mollusk. The classification and regression tree (CART) algorithm selected GSH and PC in the digestive gland and Vtg-LP as partitioning criteria for the characterization of mussel health status. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:37 pm CET

Analysis of neuroglobin mRNA expression in rat brain due to arsenite-induced oxidative stress

Abstract

Arsenic (As) in drinking water is a toxicant causing several health problems including nervous system disturbance. Neuroglobin (Ngb) is a tissue globin in nervous system playing protective role against oxidative stress in many injuries. This study was to investigate how long arsenite exposure (sodium arsenite 7.5 mg/kg/day) could induce oxidative stress in blood and brain of rats and to determine whether Ngb expression in rat brain changed due to oxidative stress. Results showed that superoxide dismutase (SOD) activity and malondialdehyde (MDA) level in serum and brain homogenates and reactive oxygen species (ROS) generation in red blood cells (RBCs) did not change in the rats exposed to arsenite for 8 weeks. In the rats exposed to arsenite for 16 weeks, SOD activity decreased (serum: P < 0.05; brain homogenates: P < 0.01) and MDA level increased (P < 0.01) in serum and brain homogenates; ROS production increased (P < 0.01) in RBC. When oxidative stress occurred, Ngb mRNA expression did not change in whole brain, cerebral cortex, midbrain, and hippocampus; however, Ngb mRNA expression increased significantly (P < 0.05) in cerebellum compared to the control group. This study suggests that arsenite exposure for 16 weeks can lead to oxidative stress of blood and brain of rats. Ngb may play a protective role incerebellum when oxidative stress occurs due to arsenite exposure. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:37 pm CET

Lead exposure in pheochromocytoma cells induces persistent changes in amyloid precursor protein gene methylation patterns

Abstract

It has been suggested that lead (Pb) exposure in early life may increase amyloid precursor protein (APP) expression and promote the pathogenesis of Alzheimer's disease in old age. The current study examined whether the DNA methylation patterns of APP gene in rat pheochromocytoma (PC12) cells changed after Pb acetate exposure. Undifferentiated PC12 cells were exposed to three doses of Pb acetate (50, 250, and 500 nM) and one control for 2 days or 1 week. The methylation patterns of APP promoter and global DNA methylation were analyzed. The DNA methyltransferase 1 (DNMT1) expression and the level of amyloid β peptide (Aβ) were also investigated. The results showed that the exposure of the three concentrations of Pb acetate could make the APP promoter hypomethylated. The global DNA methylation level and the expression of DNMT1 were changed in the 500 nM group after 2 days exposure and in the 250 and 500 nM group after 7 days exposure. Thus, Pb may exert neurotoxic effects through mechanisms that alter the global and promoter methylation patterns of APP gene. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:37 pm CET

Toxicity of silver and copper to Cucurbita pepo: Differential effects of nano and bulk-size particles

Abstract

The phytotoxicity of bulk and nanoparticle Cu and Ag was directly compared. NP Ag reduced biomass and transpiration by 66–84% when compared with bulk Ag. The Ag ion concentration was 4.4–10-times greater in NP than bulk particle solutions. The Cu ion concentration was 1.4–4.4-times greater in bulk than NP amended solutions. Humic acid (50 mg/L) decreased the ion content of bulk Cu solution by 38–42% but increased ion Cu content of NP solutions by 1.4–2.9 times. Bulk and NP Cu were highly phytotoxic; growth and transpiration were reduced by 60–70% relative to untreated controls. NP Cu phytotoxicity was unaffected by solution type, but humic acid (50 mg/L) completely alleviated phytotoxicity caused by bulk Cu. The data demonstrate differential toxicity of Ag NP relative to bulk Ag. The finding that humic acid and solution chemistry differentially impact bulk and NP behavior highlights the importance of evaluating nanoparticles under environmentally relevant conditions. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:37 pm CET

Comparing toxicity endpoints on Lecane quadridentata (Rotifera: Monogononta) exposed to two anticholinesterases pesticides

Abstract

Toxicity tests were performed on the freshwater rotifer Lecane quadridentata exposed to the pesticides carbaryl and methyl parathion (lethal, sublethal, and chronic) to compare the sensitivity between different endpoints: (a) 48-h mortality; (b) 30-min in vivo inhibition of esterase activity; (c) 5-day inhibition of the instantaneous growth rate. The emphasis of this work was to find the most appropriate endpoint to evaluate the toxicity of these pesticides in view of their sensitivity, duration, and ecological relevance. The comparison between the three toxicity tests show that the 5-day chronic tests have the lowest EC50 (2.22 and 6.6 mg/L), lowest-observed-effect concentration (2.5 and 2.5 mg/L), and no-observed-effect concentration (1.0 and 1.2 mg/L) values for carbaryl and methyl parathion, respectively. This indicates that the estimate of the instantaneous rate of natural increase r is the most sensitive endpoint regarding the toxicity of these pesticides. This sensitivity might be due to the effect on reducing the growth potential form the first generation on. Lethal and sublethal tests are closely related, suggesting that the immediate effect after inhibition of esterases is death. In general, the sensitivity of L. quadridentata is similar to other species of rotifers exposed to methyl parathion. Therefore, the 5-day chronic toxicity test with the freshwater rotifer L. quadridentata should be considered a good candidate to evaluate the effect of anticholinesterase pesticides, due to its high sensitivity and ecological relevance. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Nov 2010 | 9:37 pm CET

Toxic effect on tissues and differentially expressed genes in hepatopancreas identified by suppression subtractive hybridization of freshwater pearl mussel (Hyriopsis cumingii) following microcystin-LR challenge

Abstract

Microcystins are a family of potent hepatotoxins produced by freshwater cyanobacteria and can cause animal intoxications and human diseases. In this study, the effect of microcystin-LR (MC-LR) on the tissues of freshwater pearl mussel (Hyriopsis cumingii) was evaluated and differentially expressed genes in the hepatopancreas of the mussel exposed to MC-LR were identified. HPLC analysis of cell extracts from various tissues of the mussel indicated that the hepatopancreas had the highest MC-LR levels (55.78 ± 6.73 μg g−1 DW) after15-day exposure. The MC-LR concentration in gill or muscle was an order of magnitude less than in hepatopancreas or gonad. Subtractive cDNA library was constructed by suppression subtractive hybridization (SSH), and ∼400 positive clones were sequenced, from which 98 high quality sequences were obtained by BLAST analysis. The screening identified numerous genes involved in apoptosis, signal transduction, cytoskeletal remodel, innate immunity, material and energy metabolism, translation and transcription which were extensively discussed. The results of this study add large amount of information to the mussel genome data, and for the first time present the basic data on toxicity effect of MC-LR on mussel. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 18 Oct 2010 | 8:46 pm CEST

Antioxidant and metabolic impairment result in DNA damage in arsenic-exposed individuals with severe dermatological manifestations in Eastern India

Abstract

Arsenic is an environmental toxicant, free-radical generator, carcinogenic agent, and aging promoter. Recently, blood samples were analyzed from individuals (control- male 12, female 13; arsenic-exposed- male 16, female 14; and exposed to ≥100 μg/L As, ≥10 y) with dermatological symptoms in few affected villages in Eastern India to unravel their hematopoietic, metabolic, and antioxidant profiles. White blood cells recovered from buffy coat were used for DNA fragmentation test. Present observation suggests that significant number of individuals developed pigmentation and palmoplantar hyperkeratosis with black-brownish patch on their body and many of those developed carcinomas. Hematopoietic data show a significant increase in eosinophil and decrease in monocyte count in either sex. Though insignificant, an increase in neutrophil in female and lymphocyte count in male arsenic-exposed individuals are supported by the earlier report on sex dimorphic immune sensitization. Significant increase in serum alanine transaminase in both sexes and bilirubin only in male suggests the eventuality of hepatic disintegration. Arsenic exposure significantly decreased serum amylase in female. A significant decrease in antioxidant components like catalase, soluble thiol, and recently recognized uric acid worsened the situation by generating free radicals as observed in significant rise in malondialdehyde level, which finally increased DNA fragmentation and arsenic-associated mutagenesis and carcinogenesis. This could attribute to lowering in immune competence and related necrotic and/or apoptotic manifestations. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 5 Oct 2010 | 10:52 pm CEST

Capsaicin induces apoptosis in SCC-4 human tongue cancer cells through mitochondria-dependent and -independent pathways

Abstract

Although there have been advances in the fields of surgery, radiotherapy, and chemotherapy of tongue cancer, the cure rates are still not substantially satisfactory. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is the major pungent ingredient of hot chili pepper and has been reported to have an antitumor effect on many human cancer cell types. The molecular mechanisms of the antitumor effect of capsaicin are not yet completely understood. Herein, we investigated whether capsaicin induces apoptosis in human tongue cancer cells. Capsaicin decreased the percentage of viable cells in a dose-dependent manner in human tongue cancer SCC-4 cells. In addition, capsaicin produced DNA fragmentation, decreased the DNA contents (sub-G1 phase), and induced G0/G1 phase arrest in SCC-4 cells. We demonstrated that capsaicin-induced apoptosis is associated with an increase in reactive oxygen species and Ca2+ generations and a disruption of the mitochondrial transmenbrane potential (ΔΨm). Treatment with capsaicin induced a dramatic increase in caspase-3 and -9 activities, as assessed by flow cytometric methods. A possible mechanism of capsaicin-induced apoptosis is involved in the activation of caspase-3 (one of the apoptosis-executing enzyme). Confocal laser microscope examination also showed that capsaicin induced the releases of AIF, ATF-4, and GADD153 from mitochondria of SCC-4 cells. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 5 Oct 2010 | 10:52 pm CEST

Arsenic trioxide (As2O3) inhibits murine WEHI-3 leukemia in BALB/c mice in vivo

Abstract

Arsenic trioxide (As2O3) is used clinically to treat acute promyelocytic leukemia (APL) and has activity in vitro for induction of apoptosis in several solid tumor cell lines. To investigate the potential therapeutic application of As2O3 for leukemia, we analyzed the effects of As2O3 on the WEHI-3 cells-induced orthotopic leukemia animal model in vivo in this study. We established the WEHI-3 cells leukemia mice through the injection of murine WEHI-3 cells into BALB/c mice, and they were then treated with As2O3 (0.9 and 4.5 mg kg−1; p.o.) and/or combined with all-trans-retinoic acid (ATRA), (30 mg kg−1; i.p.). The results indicated that (1) As2O3 alone or As2O3 combined with ATRA promoted the total survival rate of leukemia mice and these effects are dose-dependent; (2) As2O3 did not affect the body weight but decreased the spleen weight; however, it did not affect liver weight; (3) As2O3 alone or As2O3 combined with ATRA increased the levels of CD3 and CD19, indicating that the differentiation of T and B cells were promoted; and (4) As2O3 alone or As2O3 combined with ATRA did not change the levels of Mac-3 and CD11b markers, indicating that the differentiation of the precursor of macrophage were not inhibited. Based on these observations, As2O3 alone or As2O3 combined with ATRA have efficacious antileukemia activity in WEHI-3 cells leukemia in vivo. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 30 Sep 2010 | 6:21 pm CEST

The effect of sodium metabisulphite on active avoidance performance in hypercholesterolemic rats

Abstract

The purpose of this study was to investigate the effects of hypercholesterolemia and sulphite on active avoidance learning. Male Wistar rats were divided into eight groups as follows: Control (C), Sulphite (S), Vitamin E (E), Sulphite + Vitamin E (SE), Hypercholesterolemia (H), Hypercholesterolemia + Sulphite (HS), Hypercholesterolemia + Vitamin E (HE), and Hypercholesterolemia + Sulphite + Vitamin E (HSE). At the end of the experimental period, the serum cholesterol level (mean ± SD) was significantly higher in H group (111.5 ± 11.11 mg dL−1) as compared to C group (63.5 ± 4.9 mg dL−1). Levels of thiobarbituric acid reactive substances (TBARS) were increased in HS group as compared to C, H, and S groups. Vitamin E reduced TBARS levels in HSE group compared with HS group. Active avoidance results indicated that hypercholesterolemia was associated with learning impairment. Our data clearly revealed that the combination of hypercholesterolemia and sulphite results in exaggerated impairment of active avoidance. Vitamin E improved active avoidance in HSE group compared with HS group. Therefore, the synergistic effect of hypercholesterolemia and sulphite may be associated with a considerable health risk. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Sep 2010 | 9:58 pm CEST

The effects of ammonium perchlorate on thyroid homeostasis and thyroid-specific gene expression in rat

Abstract

Perchlorate, a kind of inorganic chemical, is mainly used in defense industry and widely used in other civilian areas. It was well known that perchlorate exerts its thyrotoxicant effect on thyroid homeostasis via competitive inhibition of iodide uptake. However, some details of mechanism by which perchlorate disturb thyroid homeostasis are unknown and remain to be elucidated. The present study aimed to investigate if iodide insufficiency in the thyroid is the main mechanism by which perchlorate exerts its effect on the thyroid gland. We highlighted and measured the gene expression of NIS, Tg, and TPO which involved in thyroid hormone biosynthesis. Thyroid effects of perchlorate were identified by assessing different responses of these genes at the treatments of perchlorate and iodine deficiency. The results indicated that high dose perchlorate (520 mg kg−1 b.wt.) can induce a significant decrease in body weight and cause hypertrophy of thyroid gland, with a decreased level of FT3, FT4 and a remarkable increased level of TSH. In addition, the significant decreased gene expression of Thyroglobulin (Tg) and thyroperoxidase (TPO) were both observed at the treatment of high dose perchlorate. These results suggested that perchlorate can suppress gene expression of Tg and TPO which directly involved in biosynthesis of thyroid hormones, and may therefore aggravate the perturbation of thyroid homeostasis in addition to competitive inhibition of iodide uptake. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Sep 2010 | 9:57 pm CEST

1H NMR-based metabolomics approach to assess toxicity of bunker a heavy oil to freshwater carp, Cyprinus carpio

Abstract

Using a 1H NMR metabolomics approach, the effects of dietary exposure of bunker A heavy oil (0.01, 0.1, 1, and 5% in diet) on freshwater carp, Cyprinus carpio, were examined. Statistical analysis by PCA score plots showed that the amount of metabolites in exposure groups 0.1, 1, and 5% differed from those in the control group. Although no discernible effects on metabolites were noted in the 0.1% exposure group as well as in the lowest concentration (0.01%) group, several metabolites such as amino acid (e.g., leucine, isoleucine, valine, glutamine, histidine, proline, and methionine), 3-D-hydroxybutyrate, and glycerol were elevated, while another metabolite such as formate was reduced in 1 and 5% groups. These changes in the metabolites associated with the tri-carboxylic-acid (TCA) cycle suggest that oil exposure resulted in the disturbance of the TCA cycle in the liver of the carp. Isobutyrate, a marker of anoxia, was also increased in 1 and 5% exposures groups and was directly related to low hemoglobin concentrations leading to reduced oxygen transport by blood. In addition, significant elevation of creatinine in the plasma of carps exposed to 5% heavy oil suggests disturbance in kidney function. Thus, metabolomics approach can detect toxic effects of hazardous pollutants on fish. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Quelle: Environmental Toxicology | 29 Sep 2010 | 9:57 pm CEST

Environmental nitration processes enhance the mutagenic potency of aromatic compounds

Abstract

This work is an attempt to establish if aromatic nitration processes are always associated with an increase of genotoxicity. We determined the mutagenic and genotoxic effects of Benzene (B), Nitrobenzene (NB), Phenol (P), 2-Nitrophenol (2-NP), 2,4-Dinitrophenol (2,4-DNP), Pyrene (Py), 1-Nitropyrene (1-NPy), 1,3-Dinitropyrene (1,3-DNPy), 1,6-Dinitropyrene (1,6-DNPy), and 1,8-Dinitropyrene (1,8-DNPy). The mutagenic activities were evaluated with umuC test in presence and in absence of metabolic activation with S9 mix. Then, we used both cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes on human lymphocytes in order to evaluate the genotoxic effects. Analysis of all results shows that nitro polycyclic aromatic hydrocarbons (PAHs) are definitely environmental genotoxic/mutagenic hazards and confirms that environmental aromatic nitration reactions lead to an increase in genotoxicity and mutagenicity properties. Particularly 1-NPy and 1,8-DNPy can be considered as human potential carcinogens. They seem to be significant markers of the genotoxicity, mutagenicity, and potential carcinogenicity of complex PAHs mixtures present in traffic emission and industrial environment. In prevention of environmental carcinogenic risk 1-NPy and 1,8-DNPy must therefore be systematically analyzed in environmental complex mixtures in association with combined umuC test, CBMN assay, and FISH on cultured human lymphocytes. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Quelle: Environmental Toxicology | 24 Aug 2010 | 6:27 pm CEST

Retracted: Long-term copper toxicity in apple trees (Malus pumila Mill) and bioaccumulation in fruits

Abstract

The following article from Environmental Toxicology, ‘Long-term Copper Toxicity in Apple Trees (Malus pumila Mill) and Bioaccumulation in Fruits’ by Bai-Ye Sun, Shi- Hong Kan, Yan-Zong Zhang, Jun Wu, Shi-Huai Deng, Chun-Sheng Liu and Gang Yang, published online on January 15, 2010 in Wiley InterScience (www.interscience.wiley.com; DOI: 10.1002/tox.20565), has been retracted by agreement between the authors, the journal Editor in Chief, Dr. Paul Tchounwou, and Wiley Periodicals, Inc. The retraction has been agreed at the request of the authors due to overlap with ‘Copper Toxicity and Bioaccumulation in Chinese Cabbage (Brassica pekinensis Rupr.)’ by Zhi-Ting Xiong and Hai Wang, published in Environmental Toxicology, Volume 20, pages 188–194, 2005.

Quelle: Environmental Toxicology | 15 Jan 2010 | 6:00 am CET




 


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