Middle school students co-author research on enzyme for activating promising disease-fighters

Grown-ups aren't the only ones making exciting scientific discoveries these days. Two middle school students from Wisconsin joined a team of scientists who are reporting the first glimpse of the innermost structure of a key bacterial enzyme. It helps activate certain antibiotics and anti-cancer agents so that those substances do their job. Their study appears in ACS' weekly journal Biochemistry. The student co-authors of the study are from Edgewood Campus Middle School in Madison and participated in Project CRYSTAL, a special program that provides middle school students with hands-on laboratory experience.

In the report, study leader Hazel Holden and colleagues note intense scientific interest in a chemical process called methylation, which increases the activity of DNA, proteins, and other substances in the body by transferring methyl (CH₃) groups to them. Special enzymes called methyltransferases make methylation possible, and these proteins are very important in a myriad of key biological processes.

Holden and colleagues studied a bacterial methyltransferase involved in the production of tetronitrose, a component of the promising anti-cancer agent, tetrocarcin, and the antibiotic kijanimicin. The methyltransferase seems to play a key role in activating these disease-fighters. The scientists identified the 3D structure of this methyltransferase, a key step in determining how it works and how it might be modified for potential use in medicine.

Biochemistry: "Molecular Architecture of a C-3'-Methyltransferase Involved in the Biosynthesis of D-Tetronitrose" [Biochemistry, 2010, 49 (28), pp 5891?5898; DOI: 10.1021/bi100782b].

The fungus among us: A new way of decomposing BPA-containing plastic

Just as cooking helps people digest food, pretreating polycarbonate plastic - source of a huge environmental headache because of its bisphenol A (BPA) content - may be the key to disposing of the waste in an eco-friendly way, scientists have found.

Their new study is in ACS' Biomacromolecules, a monthly journal.

Mukesh Doble and Trishul Artham note that manufacturers produce about 2.7 million tons of plastic containing BPA each year. Polycarbonate is an extremely recalcitrant plastic, used in everything from screwdriver handles to eyeglass lenses, DVDs, and CDs. Some studies have suggested that the BPA may have a range of adverse health effects, sparking the search for an environmentally safe way of disposing of waste plastic to avoid release of BPA.

The scientists pretreated polycarbonate with ultraviolet light and heat and exposed it to three kinds of fungi - including the fabled white-rot fungus, used commercially for environmental remediation of the toughest pollutants. The scientists found that fungi grew better on pretreated plastic, using its BPA and other ingredients as a source of energy and breaking down the plastic. After 12 months, there was almost no decomposition of the untreated plastic, compared to substantial decomposition of the pretreated plastic, with no release of BPA.

Biomacromolecules:

"Biodegradation of Physiochemically Treated Polycarbonate by Fungi" [Biomacromolecules, 2010, 11 (1), pp 20?28; DOI: 10.1021/bm9008099].

Cow-a-bella - making eco-friendly diesel fuel from butter

The search for new raw materials for making biodiesel fuel has led scientists to an unlikely farm product - butter. In a new study in ACS' bi-weekly Journal of Agricultural and Food Chemistry, they report that butter could be used as an eco-friendly feedstock, or raw material, for making diesel fuel.

Michael Haas and colleagues cite rising global demand for biodiesel, and the desire to expand the feedstock base, as motivating factors for their research. The United States alone has committed to producing 36 billion gallons of biofuel by 2022, a major increase from the current annual production level of about 11 billion gallons. Most of that was ethanol. Biodiesel production, now approaching 1 billion gallons annually in the U.S., is also slated to increase. As researchers seek additional and affordable feedstocks for biodiesel production, these scientists turned to butter, one billion pounds of which are produced annually. Could surplus, spoiled, or nonfood-grade butter be used to make biodiesel at competitive prices?

In an effort to find out, the scientists recovered the fat from a quarter-ton of butter and converted it into the fatty acid esters that constitute biodiesel. They found that the resulting material met all but one of the official test standards for biodiesel. The study concluded that with further purification or by blending with biodiesel from other feedstocks butter biodiesel could add to the supply of biobased fuel for diesel engines.

Journal of Agricultural and Food Chemistry: "Butter as a Feedstock for Biodiesel Production" [J. Agric. Food Chem., 2010, 58 (13), pp 7680?7684; DOI: 10.1021/jf1003754].

Small materials poised for big impact in construction

Bricks, blocks, and steel I-beams - step aside. A new genre of construction materials, made from stuff barely 1/50,000th the width of a human hair, is about to debut in the building of homes, offices, bridges, and other structures. And a new report is highlighting both the potential benefits of these nanomaterials in improving construction materials and the need for guidelines to regulate their use and disposal. The report appears in the monthly journal ACS Nano.

Pedro Alvarez and colleagues note that nanomaterials likely will have a greater impact on the construction industry than any other sector of the economy, except biomedical and electronics applications. Certain nanomaterials can improve the strength of concrete, serve as self-cleaning and self-sanitizing coatings, and provide many other construction benefits. Concerns exist, however, about the potential adverse health and environmental effects of construction nanomaterials.

The scientists analyzed more than 140 studies on the benefits and risks of nanomaterials. They found that the materials can provide a wide variety of benefits for the construction industry, ranging from greater strength and durability to improved energy efficiency. The report also identified potential adverse health and environmental effects, and cites the importance of developing guidelines to regulate the use and disposal of construction nanomaterials.

ACS Nano: "Nanomaterials in the Construction Industry: A Review of Their Applications and Environmental Health and Safety Considerations" [ACS Nano, 2010, 4 (7), pp 3580?3590; DOI: 10.1021/nn100866w].

Toward a new generation of superplastics

Scientists are reporting an in-depth validation of the discovery of the world's first mass producible, low-cost, organoclays for plastics. The powdered material, made from natural clay, would be a safer, more environmentally friendly replacement for the compound widely used to make plastics nanocomposites. A report on the research appears in ACS' Macromolecules, a bi-weekly journal.

Miriam Rafailovich and colleagues focused on a new organoclay developed and patented by a team of scientists headed by David Abecassis. The scientists explain that so-called quaternary amine-treated organoclays have been pioneering nanoparticles in the field of plastics nanotechnology. Just small amounts of the substances make plastics flame retardant, stronger, and more resistant to damage from ultraviolet light and chemicals. They also allow plastics to be mixed together into hybrid materials from plastics that otherwise would not exist. However, quaternary amine organoclays are difficult to produce because of the health and environmental risks associated with quaternary amines, as well as the need to manufacture them in small batches. These and other disadvantages, including high cost, limit use of the materials.

The new organoclay uses resorcinol diphenyl phosphate (which is normally a flame retardant), to achieve mass producible organoclays which can be made in continuous processing. In addition these organoclays are cheaper, generate less dust, and are thermostable to much higher temperatures (beyond 600 degrees Fahrenheit). This clay has also been proven to be superior for flame retardance applications. In addition, unlike most quaternary amine based organoclays, it works well in styrene plastics, one of the most widely used kinds of plastic.

Macromolecules: "The Role of Surface Interactions in the Synergizing Polymer /Clay Flame Retardant Properties" [Macromolecules, 2010, 43 (12), pp 5338?5351; DOI: 10.1021/ma100669g].

New evidence that chili pepper ingredient fights fat

Capsaicin, the stuff that gives chili peppers their kick, may cause weight loss and fight fat buildup by triggering certain beneficial protein changes in the body, according to a new study on the topic. The report, which could lead to new treatments for obesity, appears in ACS' monthly Journal of Proteome Research.

Jong Won Yun and colleagues point out that obesity is a major public health threat worldwide, linked to diabetes, high blood pressure, heart disease, and other health problems. Laboratory studies have hinted that capsaicin may help fight obesity by decreasing calorie intake, shrinking fat tissue, and lowering fat levels in the blood. Nobody, however, knows exactly how capsaicin might trigger such beneficial effects.

In an effort to find out, the scientists fed high-fat diets with or without capsaicin to lab rats used to study obesity. The capsaicin-treated rats lost 8 percent of their body weight and showed changes in levels of at least 20 key proteins found in fat. The altered proteins work to break down fats. "These changes provide valuable new molecular insights into the mechanism of the antiobesity effects of capsaicin," the scientists say.

Journal of Proteome Research: "Proteomic Analysis for Antiobesity Potential of Capsaicin on White Adipose Tissue in Rats Fed with a High Fat Diet" [J. Proteome Res., 2010, 9 (6), pp 2977?2987; DOI: 10.1021/pr901175w].

Gulf oil dispersants unlikely to be endocrine disruptors and have relatively low cell toxicity

Government scientists are reporting that eight of the most commonly used oil dispersants used to fight oil spills, such as the massive episode in the Gulf of Mexico, appear unlikely to act as endocrine disruptors - hormone-like substances that can interfere with reproduction, development, and other biological processes. The tested dispersants also had a relatively low potential for cytotoxicity (cell death), with JD-2000 and SAF-RON GOLD showing the least potential. The scientists are with the U. S. Environmental Protection Agency and the National Institutes of Health Chemical Genomics Center. Their findings appear in ACS' semi-monthly journal Environmental Science & Technology.

Richard Judson and colleagues note that more than 1.5 million gallons of dispersants have been used so far in the Deepwater Horizon spill. These detergent-like chemicals break up oil slicks into small drops. Scientists are concerned that some dispersants contain ingredients that turn into endocrine disruptors in the environment, and could harm marine mammals, fish, and humans. But only limited toxicity testing data is available on currently-used dispersants, and this is only results from the first round of EPA dispersant testing, they state.

With an urgent need for such information in the Deepwater Horizon spill, the scientists applied a rapid screening method using mammalian cells to determine the eight dispersants' potential to act as endocrine disruptors and relative toxicity to living cells. The dispersants included a type widely being used to treat the Gulf oil spill. None of the substances showed significant endocrine disruption activity and cytotoxicity was not seen until dispersants were tested at concentrations above 10 parts per million, the scientists said. However, they note that "there are other routes by which chemicals can cause endocrine disruption, as well as other types of toxicity that have not been tested for here."

Environmental Science & Technology: "Analysis of Eight Oil Spill Dispersants Using Rapid, In Vitro Tests for Endocrine and Other Biological Activity" [Environ. Sci. Technol., Article ASAP; DOI: 10.1021/es102150z].

New antibacterial material for bandages, food packaging, shoes

A new form of paper with the built-in ability to fight disease-causing bacteria could have applications that range from anti-bacterial bandages to food packaging that keeps food fresher longer to shoes that ward off foot odor. A report about the new material, which consists of the thinnest possible sheets of carbon, appears in ACS Nano, a monthly journal.

Chunhai Fan, Qing Huang, and colleagues explained that scientists in the United Kingdom first discovered the material, known as graphene, in 2004. Since then, the race has been on to find commercial and industrial uses for graphene. Scientists have tried to use graphene in solar cells, computer chips, and sensors. Fan and Huang decided to see how graphene affects living cells.

So they made sheets of paper from graphene oxide, and then tried to grow bacteria and human cells on top. Bacteria were unable to grow on the paper, and it had little adverse effect on human cells. "Given the superior antibacterial effect of graphene oxide and the fact that it can be mass-produced and easily processed to make freestanding and flexible paper with low-cost, we expect this new carbon nanomaterial may find important environmental and clinical applications," the reports states.

Nano: "Graphene-Based Antibacterial Paper" in

[ACS Nano, Article ASAP; DOI: 10.1021/nn101097v].

Toward making 'extended blood group typing' more widely available

Scientists are reporting an advance toward enabling more blood banks to adopt so-called "extended blood group typing," which increases transfusion safety by better matching donors and recipients. Their report on a new, automated genetic method for determining a broader range of blood types appears in ACS' Analytical Chemistry, a semi-monthly journal.

Christophe Marquette and colleagues explain that most blood banks still use a century-old blood approach to blood typing. It identifies blood group antigens on red blood cells - proteins that must match in donor and recipient to avoid potentially serious transfusion reactions. Most blood currently is typed for only a few of the 29 known human blood groups, even though some rare blood groups can affect the outcome of a transfusion. Commercial technology does exist for extended typing with DNA tests. However, it is expensive, difficult to use, and suited more for research labs than high-volume blood centers, they state. Wide adoption of extended blood group typing, they note, requires a test that can handle the high volume of blood processed each year - 14 million donations in the United States, for instance, and 20 million in Europe.

The study describes evaluation of the new more affordable method, called the HiFi Blood 96, which types blood with DNA testing in a high-speed automated procedure. Tests on 293 human blood samples demonstrated the performance and reliability of the new method. The report compares HiFi Blood 96 to existing commercial tests, and discusses improvements that are underway.

Analytical Chemistry: "Robust, High-Throughput Solution for Blood Group Genotyping" [Anal. Chem., Article ASAP; June 18, 2010; DOI: 10.1021/ac101008d].

Supercharged proteins enter biology's forbidden zone

Scientists are reporting discovery of a way to help proteins such as the new generation of protein-based drugs - sometimes heralded as tomorrow's potential "miracle cures" - get past the biochemical "Entrance Forbidden" barrier that keeps them from entering cells and doing their work. The new technique, described in the monthly journal, ACS Chemical Biology, represents a new use for an engineered form of green fluorescent protein, the topic of the 2008 Nobel Prize in Chemistry that is one of the most important research tools in biosciences.

In the report, David Liu and his colleagues describe the difficulty of delivering proteins from the outside of mammalian cells into their interiors. For that reason, nearly all of the blockbuster drugs that are proteins must do their work on the exterior of cells, activating receptors that send signals to the interior. This constraint greatly limits the scope of protein-based drugs. Liu's solution: Attaching proteins to molecules of "supercharged" green fluorescent protein, which they mutated to give it a very high positive charge. When the hybrid proteins bump into the surface of a cell, they get pulled inside by negatively charged molecules called proteoglycans.

Liu and his team tested the hybrid proteins on five types of cells, and found that they were extremely good at carrying their protein cargo inside. In fact, the supercharged protein was up to 100 times better at getting proteins into cells compared to other approaches. The delivered proteins were able to go to their target locations in the cell, such as the nucleus or cytoplasm, and perform their jobs. "To our knowledge, this is the first report of functional delivery of an enzyme into retinal cells in vivo," the researchers state.

Chemical Biology: "Potent Delivery of Functional Proteins into Mammalian Cells in Vitro and in Vivo Using a Supercharged Protein" [ACS Chem. Biol., Article ASAP; DOI: 10.1021/cb1001153].

Mercury levels are increasing in popular species of game fish in Lake Erie

Mercury levels in a popular species of game fish in Lake Erie are increasing after two decades of steady decline, scientists are reporting. The study, the most comprehensive to date on mercury levels in Great Lakes fish, is in ACS' Environmental Science & Technology, a semi-monthly journal.

Satyendra Bhavsar and colleagues note that the Great Lakes is the largest group of freshwater lakes in the world. The lakes are of significant economic importance to the United States and Canada due to the area's $7 billion fishing industry. High levels of mercury in fish can potentially cause adverse health effects in people. Although government regulations and improved emissions control technologies have greatly reduced mercury emissions in the environment, their impact on mercury levels in Great Lakes fish is unclear.

The scientists studied mercury levels in 5807 fish samples collected from the lakes between the 1970s and 2007. The samples included lake trout and walleye, two of the most common species of game fish caught in the region. The researchers found that mercury levels in the fish steadily declined from the mid-1970s to 2007 in the upper Great Lakes (Superior and Huron). In recent years (between 1990 and 2007), however, the mercury concentrations leveled-off in Lake Ontario walleye but appear to be increasing in Lake Erie walleye. The mercury increases in Lake Erie walleye are likely caused by a combination of factors, including modifications in Lake Erie's foodweb due to invasions of dreissenid mussels and round goby, the scientists suggest.

Environmental Science & Technology: "Changes in Mercury Levels in Great Lakes Fish Between 1970s and 2007" [Environ. Sci. Technol., 2010, 44 (9), pp 3273?3279; DOI: 10.1021/es903874x].

Submarines could use new nanotube technology for sonar and stealth

Speakers made from carbon nanotube sheets that are a fraction of the width of a human hair can both generate sound and cancel out noise - properties ideal for submarine sonar to probe the ocean depths and make subs invisible to enemies. That's the topic of a report on these "nanotube speakers," which appears in ACS' Nano Letters, a monthly journal.

Ali Aliev and colleagues explain that thin films of nanotubes can generate sound waves via a thermoacoustic effect. Every time that an electrical pulse passes through the microscopic layer of carbon tubes, the air around them heats up and creates a sound wave. Chinese scientists first discovered that effect in 2008, and applied it in building flexible speakers. In a remarkable demonstration, which made its way onto YouTube, the Chinese nanoscientists stuck a sheet of nanotubes onto the side of a flag, and attached it to an mp3 player. They used the nanotube-coated flag to play a song while it flapped in the breeze. But they did not test its ability to operate under water.

Aliev's group took that step, showing that nanotube sheets produce the kind of low-frequency sound waves that enable sonar to determine the location, depth, and speed of underwater objects. They also verified that the speakers can be tuned to specific frequencies to cancel out noise, such as the sound of a submarine moving through the depths.

Nano Letters: "Underwater Sound Generation Using Carbon Nanotube Projectors" [Nano Lett., Article ASAP; May 27, 2010; DOI: 10.1021/nl100235n].