Chemistry News Archive November 2009

'Smell of old books' offers clues to help preserve them

Scientists may not be able to tell a good book by its cover, but they now can tell the condition of an old book by its smell. In a report in ACS' Analytical Chemistry, a semi-monthly journal, they describe development of a new test that can measure the degradation of old books and precious historical documents based on their smell. The nondestructive "sniff" test could help libraries and museums preserve a range of prized paper-based objects, some of which are degrading rapidly due to advancing age, the scientists say.

Matija Strlic and colleagues note in the new study that the familiar musty smell of an old book, as readers leaf through the pages, is the result of hundreds of so-called volatile organic compounds (VOCs) released into the air from the paper. Those substances hold clues to the paper's condition, they say. Conventional methods for analyzing library and archival materials involve removing samples of the document and then testing them with traditional laboratory equipment. But this approach destroys part of the document.

The new technique, called "material degradomics," analyzes the gases emitted by old books and documents without altering the documents themselves. They used it to "sniff" 72 historical papers from the 19th and 20th centuries, including papers containing rosin (pine tar) and wood fiber, which are the most rapidly degrading paper types in old books. The scientists identified 15 VOCs that seem good candidates as markers to track the degradation of paper in order to optimize their preservation. The method also could help preserve other historic artifacts, they add.

Analytical Chemistry: "Material Degradomics: On the Smell of Old Books" [Anal. Chem., 2009, 81 (20), pp 8617?8622; DOI: 10.1021/ac9016049].

The buzz on fruit flies: New role in the search for addiction treatments

Fruit flies may seem like unlikely heroes in the battle against drug abuse, but new research suggests that these insects - already used to study dozens of human disease - could claim that role. Scientists are reporting that fruit flies can be used as a simpler and more convenient animal model for studying the effects of cocaine and other drugs of abuse on the brain. Their study appears online in ACS Chemical Neuroscience, a new monthly journal.

Andrew Ewing and colleagues note that laboratory mice, rats, and monkeys have been mainstays in research with the ultimate goal of finding effective medicines for treating addiction. Although these mammals have helped establish the behavioral effects of cocaine on the body, they provide relatively complicated models to study the effects of cocaine and other illicit drugs on the brain and nerves. In the hope for a new simpler animal model they turned to fruit flies, which have many biological similarities to mammals, but are easier to study.

The scientists confirmed those hopes in research that involved giving cocaine, amphetamine, methamphetamine, and methylphenidate to fruit flies and then studying brain chemistry with a microelectrode one-twentieth the diameter of a human hair. The results demonstrate that fruit flies are a valid model for studying drug addiction in humans, the scientists say.

ACS Chemical Neuroscience: "Using in Vivo Electrocemistry To Study the Physiological Effects of Cocaine and Other Stimulants on the Drosophila melanogaster Dopamine Transporter" [ACS Chem. Neurosci., Article ASAP; DOI: 10.1021/cn900017w].

Discovery of the Jekyll-and-Hyde factors in 'coral bleaching'

Scientists are reporting the first identification of substances involved in the Jekyll-and-Hyde transformation that changes harmless marine bacteria into killers that cause "coral bleaching." Their study appears in ACS' Environmental Science & Technology, a semi-monthly journal.

Dan Bearden and colleagues note that bleaching already has destroyed up to 30 percent of the world's coral reefs, and scientists are searching for ways to slow or stop the damage. One known culprit is an ocean-dwelling bacterium, Vibrio coralliilyticus (V. coralliilyticus) that chokes-off corals' energy supply and kills these shell-clad marine animals. At lower temperatures, the bacteria are harmless to coral. But at warmer temperatures (above 75 degrees Fahrenheit) the bacteria become virulent and can kill coral.

The new study reports identification of three chemicals - betaine, glutamate, and succinate - that V. coralliilyticus produces in warmer water and are involved in the transformation. The discovery opens the door to understanding the biology involved in the complex interactions between corals and bacteria and unraveling the mystery of coral bleaching, the scientists indicated.

Environmental Science & Technology: "NMR-Based Microbial Metabolomics and the Temperature-Dependent Coral Pathogen Vibrio coralliilyticus" [Environ. Sci. Technol., 2009, 43 (20), pp 7658?7664; DOI: 10.1021/es901675w].

Smokeless tobacco called 'moist snuff' is contaminated with harmful substances

A new study on the smokeless tobacco product called moist snuff - placed between lip and gum - has led scientists in Minnesota to urge the tobacco industry to change manufacturing practices to reduce snuff's content of carcinogens. Their study is published online in ACS' monthly journal Chemical Research in Toxicology. It reports that this category of tobacco products contains surprisingly high levels of certain toxic and cancer-causing substances. Called polycyclic aromatic hydrocarbons (PAHs), they may contribute to carcinogenic effects associated with smokeless tobacco use.

Irina Stepanov and colleagues note that use of moist snuff increased by almost 80 fold between 1986-2003, partially because of the notion that it is safer then cigarettes. While smokeless tobacco use is indeed associated with lower risk of cancer as compared to cigarette smoking, it can lead to precancerous oral lesions and oral, esophageal, and pancreatic cancer. Only trace amounts of one of the PAHs has been reported to be present in smokeless tobacco prior to the recent discovery by Stepanov and colleagues that at least eight PAHs are present in smokeless tobacco. This finding inspired the new research.

The scientists analyzed the PAHs in 23 moist snuff samples that included various flavors of the most popular brands sold in the U.S. They identified 23 different PAHs in the samples, of which 9 are classified as carcinogens. They conclude that PAHs are one of the most abundant groups of cancer-causing substances in moist snuff. "Urgent measures are required from the U.S. tobacco industry to modify manufacturing processes so that the levels of these toxicants and carcinogens in U.S. moist snuff are greatly reduced," the article notes.

Chemical Research in Toxicology: "Analysis of 23 Polycyclic Aromatic Hydrocarbons in Smokeless Tobacco by Gas Chromatography-Mass Spectrometry" [Chem. Res. Toxicol., Article ASAP; DOI: 10.1021/tx900281u].

New on-off 'switch' triggers and reverses paralysis in animals with a beam of light

In an advance with overtones of Star Trek phasers and other sci-fi ray guns, scientists in Canada are reporting development of an internal on-off "switch" that paralyzes animals when exposed to a beam of ultraviolet light. The animals stay paralyzed even when the light is turned off. When exposed to ordinary light, the animals become unparalyzed and wake up. Their study appears in the Journal of the American Chemical Society (JACS). It reports the first demonstration of such a light-activated switch in animals.

Neil Branda and colleagues point out that such "photoswitches" - light-sensitive materials that undergo photoreactions - have been available for years. Scientists use them in research. Doctors use light-sensitive materials and photoreactions in medicine in photodynamic therapy to treat certain forms of cancer. Those light-sensitive materials, however, do not have the reversibility that exists in photoswitching.

The JACS report describes development and successful testing of a photoswitch composed of the light-sensitive material, dithienylethene. The scientists grew transparent, pinhead-sized worms (C. elegans) and fed them a dithienylethene. When exposed to ultraviolet light, the worms turned blue and became paralyzed. When exposed to visible light, the dithienylethene became colorless again and the worms' paralysis ended. Many of the worms lived through the paralyze-unparalyze cycle. Scientists were not sure how the switch causes paralysis. The study demonstrates that photoswitches may have great potential in turning photodynamic therapy on and off, and for other applications in medicine and research, they indicate.

Journal of the American Chemical Society: "A Photocontrolled Molecular Switch Regulates Paralysis in a Living Organism" [J. Am. Chem. Soc., 2009, 131 (44), pp 15966?15967, DOI: 10.1021/ja903070u].

See also: Methods and video file of reversible nematode paralysis [AVI 18,9 MB]

Toward explaining why hepatitis B hits men harder than women

Scientists in China are reporting discovery of unusual liver proteins, found only in males, that may help explain the long-standing mystery of why the hepatitis B virus (HBV) sexually discriminates - hitting men harder than women. Their study has been published online in ACS' Journal of Proteome Research, a monthly publication.

Shuhan Sun, Fang Wang and colleagues note that chronic hepatitis B seems to progress and cause liver damage faster in men, with men the main victims of the virus's most serious complications - cirrhosis and liver cancer. Men infected with HBV also are 6 times more likely than women to develop a chronic form of the disease. About 400 million people worldwide have chronic hepatitis B, including a form that is highly infectious and can be transmitted through blood, saliva, and sexual contact.

In experiments with laboratory mice, the scientists found abnormal forms of apolipoprotein A-I (Apo A-I), a protein involved in fighting inflammation, in the livers of infected male mice but not infected females. They then identified abnormal forms of these Apo A-I proteins in blood of men infected with HBV, but not in women. In addition to explaining the gender differences, the proteins may provide important markers for tracking the progression of hepatitis B, the scientists suggest.

Journal of Proteome Research: "An altered pattern of liver apolipoprotein A-I is implicated in male chronic hepatitis B progression" [J. Proteome Res., Article ASAP, DOI: 10.1021/pr900593r].

Saliva proteins change as women age

In a step toward using human saliva to tell whether those stiff joints, memory lapses, and other telltale signs of aging are normal or red flags for disease, scientists are describing how the protein content of women's saliva change with advancing age. The discovery could lead to a simple, noninvasive test for better diagnosing and treating certain age-related diseases in women, they suggest in a report in ACS' Journal of Proteome Research, a monthly publication. These diseases include lupus, Sj?rens syndrome (associated with dry mouth and dry eye), and other immune-related disorders that affect millions of women worldwide, often at higher rates than in men.

John Yates and colleagues note that human saliva contains many different proteins involved in digestion, disease fighting, and other functions. Scientists are seeking ways to use the proteins as molecular "fingerprints" to develop quick diagnostic tests that provide an alternative to the needle sticks currently needed for blood tests. To do that, they need detailed information on how normal aging affects these proteins.

The scientists analyzed saliva proteins in healthy women aged 20-30 and 55-65. They identified 293 proteins differed between the two age groups. Most were involved in the immune system's defenses against infection. Older women had almost twice as many immune-related proteins than younger women. The results suggest that "it is critical to take into consideration these normal differences in protein expression when searching for clinically relevant, disease specific biomarkers," the article notes.

Journal of Proteome Research: "Quantitative Analysis of Age Specific Variation in the Abundance of Human Female Parotid Salivary Proteins" [J. Proteome Res., 2009, 8 (11), pp 5093?5102, DOI: 10.1021/pr900478h].

Hidden threat: Elevated pollution levels near regional airports

Scientists are reporting evidence that air pollution - a well-recognized problem at major airports - may pose an important but largely overlooked health concern for people living near smaller regional airports. Those airports are becoming an increasingly important component of global air transport systems. The study, one of only a handful to examine airborne pollutants near regional airports, suggests that officials should pay closer attention to these overlooked emissions, which could cause health problems for local residents. It appears online in ACS' Environmental Science & Technology, a semi-monthly journal.

In the new study, Suzanne Paulson and colleagues note that scientists have known for years that aircraft emissions from fuel burned during takeoffs and landings can have a serious impact on air quality near major airports. Aircraft exhaust includes pollutants linked to a variety of health problems. However, researchers know little about the impact of such emissions at general aviation or regional airports, which tend to be located closer to residential neighborhoods than major airports, the article notes.

The scientists measured a range of air pollutants near a general aviation airport for private planes and corporate jets in Southern California (Santa Monica Airport) in the spring and summer of 2008. They found that emissions of so-called ultrafine particles, which are less than 1/500th width of a human hair, were significantly elevated when compared to background pollution levels. Levels of these pollutants were up to 10 times higher at a downwind distance from the airport equal to about one football field and as much as 2.5 times higher at distance equal to about six football fields. The study suggests that "current land-use practices of reduced buffer areas around local airports may be insufficient."

Environmental Science & Technology: "Aircraft Emission Impacts in a Neighborhood Adjacent to a General Aviation Airport in Southern California" [Environ. Sci. Technol., 2009, 43 (21), pp 8039?8045, DOI: 10.1021/es900975f].

New evidence that dark chocolate helps ease emotional stress

The "chocolate cure" for emotional stress is getting new support from a clinical trial published online in ACS' Journal of Proteome Research. It found that eating about an ounce and a half of dark chocolate a day for two weeks reduced levels of stress hormones in the bodies of people feeling highly stressed. Everyone's favorite treat also partially corrected other stress-related biochemical imbalances.

Sunil Kochhar and colleagues note growing scientific evidence that antioxidants and other beneficial substances in dark chocolate may reduce risk factors for heart disease and other physical conditions. Studies also suggest that chocolate may ease emotional stress. Until now, however, there was little evidence from research in humans on exactly how chocolate might have those stress-busting effects.

In the study, scientists identified reductions in stress hormones and other stress-related biochemical changes in volunteers who rated themselves as highly stressed and ate dark chocolate for two weeks. "The study provides strong evidence that a daily consumption of 40 grams [1.4 ounces] during a period of 2 weeks is sufficient to modify the metabolism of healthy human volunteers," the scientists say.

Journal of Proteome Research: "Metabolic Effects of Dark Chocolate Consumption on Energy, Gut Microbiota, and Stress-Related Metabolism in Free-Living Subjects" [J. Proteome Res., Article ASAP, DOI: 10.1021/pr900607v].

Largest-ever database for liver proteins may lead to treatments for hepatitis

Scientists at a group of 11 research centers in China are reporting for the first time assembly of the largest-ever collection of data about the proteins produced by genes in a single human organ. Their focus was the liver, and their massive database in both protein and transcript levels could become a roadmap for finding possible new biomarkers and treatments for liver disease. Those include hepatitis and liver cancer, which is at epidemic levels in China and affects millions of people worldwide. Part of the China Human Liver Proteome Project, which was officially launched by the Ministry of Science and Technology of China (MOST) and chaired by Fuchu He.

He and colleagues point out that the liver plays many essential roles in the body, such as producing digestive enzymes, hormones, most of the proteins in the blood, storing carbohydrates for use in supplying energy to the muscles, and activates and breaks down drugs. Despite that key role, huge gaps likely exist in scientific knowledge about proteins involved in these activities.

Using 10 tissue samples of healthy liver from volunteers, they identified 6,788 non-redundant proteins in the liver samples, the largest group of proteins ever identified by scientists in any human organ. Half of the proteins have never been seen in the human liver before. One intriguing and unexplained discovery: Many of the new-found proteins appear related to diseases in the nervous system.

Journal of Proteome Research: "First Insight into the Human Liver Proteome from PROTEOME^SKY -LIVER^Hu 1.0, a Publicly Available Database" [J. Proteome Res., Article ASAP, DOI: 10.1021/pr900532r].

Exploration by explosion: Studying the inner realm of living cells

Scientists in Washington, DC, are reporting development and successful tests of a new way for exploring the insides of living cells, the microscopic building blocks of all known plants and animals. They explode the cell while it is still living inside a plant or animal, vaporize its contents, and sniff.

Akos Vertes and Bindesh Shrestha note that knowing the contents of cells is the key to understanding how healthy cells differ from those in disease. Until now, however, the only way to "look" inside an individual cell was to remove it from its natural environment in an animal or plant, or change its environment. But doing so changed the cell. Scientists never knew whether one cell differed from another because of the disease, or because they had removed it to a new environment.

The new report describes development of a new technique that uses laser pulses focused through a tiny glass fiber to explode a cell and turn its contents into vapor. Scientists then use a laboratory instrument to analyze the vapor and get a profile of the chemicals inside. It can reveal differences between diseased and healthy cells, even between adjacent cells in the same tissue. The scientists used this new technique to analyze the contents of living plant and animal cells and show that it quickly and accurately identified important chemical details that would have been overlooked using conventional techniques.

Analytical Chemistry: "In Situ Metabolic Profiling of Single Cells by Laser Ablation Electrospray Ionization Mass Spectrometry" [Anal. Chem., 2009, 81 (20), pp 8265?8271, DOI: 10.1021/ac901525g].

Telling an old book by its smell:
Aroma hints at ways of preserving treasured documents

WASHINGTON, DC - Scientists may not be able to tell a good book by its cover, but they now can tell the condition of an old book by its odor. In a report published in the American Chemical Society's Analytical Chemistry, a semi-monthly journal, they describe development of a new test that can measure the degradation of old books and precious historical documents on the basis of their aroma. The non-destructive "sniff" test could help libraries and museums preserve a range of prized paper-based objects, some of which are degrading rapidly due to advancing age, the scientists say.

Matija Strlič and colleagues note in the new study that the well-known musty smell of an old book, as readers leaf through the pages, is the result of hundreds of so-called volatile organic compounds (VOCs) relea sed into the air from the paper.

"The aroma of an old book is familiar to every user of a traditional library," the report notes. "A combination of grassy notes with a tang of acids and a hint of vanilla over an underlying mustiness, this unmistakable smell is as much a part of the book as its contents. It is the result of the several hundred VOCs off-gassing from paper and the object in general. The particular blend of compounds is a result of a network of degradation pathways and is dependent on the original composition of the object including paper substrate, applied media, and binding."

Those substances hold clues to the paper's condition, they say. Conventional methods for analyzing library and archival materials involve removing samples of the document and then testing them with traditional laboratory equipment. But this approach involves damage to the document.

The new technique - an approach called "material degradomics" - analyzes the gases emitted by old books and documents without altering the documents themselves. The scientists used it to "sniff" 72 historical papers from the 19th and 20th centuries. Some of the papers contained rosin (pine tar) and wood fiber, which are the most rapidly degrading types of paper found in old books. The scientists identified 15 VOCs that seem good candidates as markers to track the degradation of paper in order to optimize their preservation. The method also could help preserve other historic artifacts, they add.

Matija Strlič et al: "Material Degradomics: On the Smell of Old Books" [Anal. Chem., 2009, 81 (20), pp 8617?8622, DOI: 10.1021/ac9016049]

An inexpensive 'dipstick' test for pesticides in foods

Scientists in Canada are reporting the development of a fast, inexpensive "dipstick" test to identify small amounts of pesticides that may exist in foods and beverages. Their paper-strip test is more practical than conventional pesticide tests, producing results in minutes rather than hours by means of an easy-to-read color-change, they say.

The study is in the November 1 issue of ACS' Analytical Chemistry, a semi-monthly journal. John Brennan and colleagues note in the new study that conventional tests for detecting pesticides tend to use expensive and complex equipment and in some cases can take several hours to produce results. They cite a growing need for cheaper, more convenient, and more eco-friendly tests for pesticides, particularly in the food industry.

The scientists describe the development of a new paper-based test strip that changes color shades depending on the amount of pesticide present. In laboratory studies using food and beverage samples intentionally contaminated with common pesticides, the test strips accurately identified minute amounts of pesticides. The test strips, which produced results in less than 5 minutes, could be particularly useful in developing countries or remote areas that may lack access to expensive testing equipment and electricity, they note.

Analytical Chemistry: "Reagentless Bidirectional Lateral Flow Bioactive Paper Sensors for Detection of Pesticides in Beverage and Food Samples" [Anal. Chem., 2009, 81 (21), pp 9055?9064; DOI: 10.1021/ac901714h].

Curry-cure? Spicing up the effectiveness of a potential disease-fighter

Scientists are reporting development of a nano-size capsule that boosts the body's uptake of curcumin, an ingredient in yellow curry now being evaluated in clinical trials for treatment of several diseases. Their study is in ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Koji Wada and colleagues note that curcumin is a potent antioxidant found in the spice, turmeric. Clinical trials are checking its safety and effectiveness for colon cancer, psoriasis, and Alzheimer's disease. However, digestive juice in the gastrointestinal tract quickly destroys curcumin so that little actually gets into the blood.

Scientists have known for years that encapsulating insulin and certain other drugs into structures called liposomes can boost absorption. The scientists prepared the liposomes encapsulating curcumin and fed them to laboratory rats. Encapsulating more than quadrupled absorption of curcumin, and also boosted antioxidant levels in the blood. The encapsulating process could be an answer to the problem of increasing curcumin's absorption in the digestive environment of the gastrointestinal tract, they suggest.

Journal of Agricultural and Food Chemistry: "Evaluation of an Oral Carrier System in Rats: Bioavailability and Antioxidant Properties of Liposome-Encapsulated Curcumin" [J. Agric. Food Chem., 2009, 57 (19), pp 9141?9146; DOI: 10.1021/jf9013923].

New evidence supports 19th century idea on formation of oil and gas

Scientists in Washington, D.C. are reporting laboratory evidence supporting the possibility that some of Earth's oil and natural gas may have formed in a way much different than the traditional process described in science textbooks.

Their study is scheduled for Nov./Dec. issue of ACS' Energy & Fuels, a bi-monthly publication. Anurag Sharma and colleagues note that the traditional process involves biology: Prehistoric plants died and changed into oil and gas while sandwiched between layers of rock in the hot, high-pressure environment deep below Earth's surface. Some scientists, however, believe that oil and gas originated in other ways, including chemical reactions between carbon dioxide and hydrogen below Earth' surface.

The new study describes a test of that idea, which dates to at least 1877 and famous Russian chemist Dimitri Mendeelev. They combined ingredients for this so-called abiotic synthesis of methane, the main ingredient in natural gas, in a diamond-anvil cell and monitored in-situ the progress of the reaction. The diamond anvils can generate high pressures and temperatures similar to those that occur deep below Earth's surface and allow for in-situ optical spectroscopy at the extreme environments. The results "strongly suggest" that some methane could form strictly from chemical reactions in a variety of chemical environments. This study further highlights the role of reaction pathways and fluid immiscibility in the extent of hydrocarbon formation at extreme conditions simulating deep subsurface.

Energy & Fuels: "In Situ Diamond-Anvil Cell Observations of Methanogenesis at High Pressures and Temperatures" [Energy Fuels, Article ASAP; DOI: 10.1021/ef9006017].

Toward home-brewed electricity with 'personalized solar energy'

New scientific discoveries are moving society toward the era of "personalized solar energy," in which the focus of electricity production shifts from huge central generating stations to individuals in their own homes and communities. That's the topic of a report by an international expert on solar energy scheduled for the November 2 issue of ACS' Inorganic Chemistry, a bi-weekly journal. It describes a long-awaited, inexpensive method for solar energy storage that could help power homes and plug-in cars in the future while helping keep the environment clean.

Daniel Nocera explains that the global energy need will double by mid-century and triple by 2100 due to rising standards of living world population growth. Personalized solar energy - the capture and storage of solar energy at the individual or home level - could meet that demand in a sustainable way, especially in poorer areas of the world.

The report describes development of a practical, inexpensive storage system for achieving personalized solar energy. At its heart is an innovative catalyst that splits water molecules into oxygen and hydrogen that become fuel for producing electricity in a fuel cell. The new oxygen-evolving catalyst works like photosynthesis, the method plants use to make energy, producing clean energy from sunlight and water. "Because energy use scales with wealth, point-of-use solar energy will put individuals, in the smallest village in the nonlegacy world and in the largest city of the legacy world, on a more level playing field," the report states.

Inorganic Chemistry: "Chemistry of Personalized Solar Energy" [Inorg. Chem., 2009, 48 (21), pp 10001?10017; DOI: 10.1021/ic901328v].