Chemistry News Archive November 2008

Microcapsules act as "roach motel" to kill harmful bacteria

Researchers in New Mexico and Florida are reporting development of microscopic particles that act as chemical booby traps for bacteria. The traps attract and kill up to 95 percent of nearby bacteria, including microbes responsible for worrisome hospital-based infections. The scientists describe their discovery as micro-sized "roach motels" for harmful bacteria. Their study went online November 24 in the premiere issue of ACS Applied Materials & Interfaces,a new monthly journal. It is scheduled for the January 28 print edition.

In the report, David G. Whitten of the University of New Mexico and Kirk S. Schanze of the University of Florida, working together with a team of faculty and graduate student collaborators, point out that bacterial contamination of medical devices causes up to 1.4 million deaths per year. In addition, bacteria are becoming more resistant to standard disinfection methods. Scientists also are increasingly concerned about the possibility of intentional release of harmful bacteria by terrorists. As a result, researchers are attempting to develop new and improved methods of disinfection.

The New Mexico and Florida groups describe an advance toward this goal. It involves the development of light-activated, hollow microcapsules composed of an organic conducting polymer. The antibacterial microcapsules can attract, capture, and kill bacteria. In controlled laboratory tests, the researchers exposed the capsules to either Pseudomonas aeruginosa, one of the deadliest and most common hospital-based pathogens, or Cobetia marina, a type of bacterium that fouls the hulls of ships and other marine equipment. After one hour of light exposure, the light-activated capsules killed more than 95 percent of the exposed bacteria, the researchers say. The microcapsules can be applied to a variety of surfaces, including medical equipment, they add. - MTS

ACS Applied Materials & Interfaces: "Conjugated Polyelectrolyte Capsules: Light-Activated Anti-microbial Micro 'Roach Motels'".

Key advance toward treatment for most common adult form of muscular dystrophy

Scientists in New York are reporting a critical first step toward development of a long-sought drug to treat myotonic muscular dystrophy (MMD), the most common form of muscular dystrophy in adults. MMD affects about 1 in 8,000 people. Their findings are scheduled for publication in the November 8 issue of ACS' weekly Journal of the American Chemical Society.

In the study, Benjamin Miller and colleagues point out that MMD differs from typical hereditary diseases. They result from mutated DNA in genes that encodes an erroneous message that RNA picks up and passes along. As a result, cells produce faulty proteins. Those proteins disrupt cells' activity and cause symptoms of the disease. Rather, MMD is caused by wayward or "toxic" strands of RNA.

The researchers describe discovery of a family of drug-like molecules that target the errant strands of RNA, preventing production of the defective protein. The discovery, they said, provides scientists for the first time with substances that target the root cause of MMD and represent molecules that could be developed into drugs. They note that drugs more commonly target DNA or proteins, with the RNA approach offering a different and potentially valuable route to developing new medications for certain diseases. - JS

Journal of the American Chemical Society: "Dynamic Combinatorial Selection of Molecules Capable of Inhibiting the (CUG) Repeat RNA-MBNL1 Interaction In Vitro: Discovery of Lead Compounds Targeting Myotonic Dystrophy (DM1)".

Toward healthier bread and other whole grain foods

Bread, pasta, and other foods made from whole grains - known to help protect against heart disease, cancer and diabetes - may get even healthier in the future. Scientists in Europe collaborating in the European Union HEALTHGRAIN project are reporting the largest study to date comparing nutrient levels in the world's different grain varieties, which could lead to the development of healthier varieties of grain and grain-based foods, they say. Their findings will be described in a group of papers scheduled for the November 26 issue of the ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

In the new study, Peter R. Shewry and colleagues point out that whole grain foods, including wheat, rye and oats, have been widely touted in recent years for having greater health benefits than refined grains. Health-promoting ingredients in whole grains include fiber, antioxidants, folate, and other plant chemicals. As nutrient levels can vary from grain to grain, however, it is unclear which grain varieties pack the most nutritional punch, the researchers note.

To find out, the scientists grew 150 wheat varieties used for bread-making and 50 other small-grain varieties (including oats, rye, and barley) on a single farm in Hungary over a one year period. The grains, grown from lines originating worldwide, were then harvested, milled, and analyzed for a range of plant chemicals and fiber components considered to have health benefits. The researchers identified grain varieties with high levels of healthy components that could be used to breed new, nutrient-rich varieties of grain for healthier whole grain foods.

Journal of Agricultural and Food Chemistry: "The HEALTHGRAIN Cereal Diversity Screen: Concept, Results, and Prospects".

Gene "silencing" may improve success of islet cell transplants for diabetes

Scientists in Tennessee are reporting that a gene therapy technique called "gene silencing" shows promise for improving the effectiveness and expanded use of transplants of insulin-producing cells to treat diabetes. The study is scheduled for the December 1 issue of ACS' Molecular Pharmaceutics, a bi-monthly journal.

In the new study, Ram Mahato, Guofeng Cheng, and Lin Zhu point out that transplantation of the pancreas's insulin producing cells, called islet cells, has great potential for treating patients with insulin-dependent diabetes. However, the procedure currently is ineffective for most people due to a tendency of the body's immune system to reject transplanted cells. Studies by others indicate that a specific enzyme, caspase-3, plays a key role in carrying-out this destructive process.

To address this problem, the scientists genetically modified islet cells in the laboratory to turn off, or "silence" the gene responsible for producing caspase-3. When the modified cells were transplanted into the kidneys of mice with insulin-dependent diabetes, the blood glucose levels of the mice became normal for up to 32 days, the scientists say. When the cells were removed, the blood glucose levels of the mice returned to high levels similar to pre-transplantation levels, confirming that the transplanted cells were functional and effective, the researchers say. - MTS

Molecular Pharmaceutics: "Caspase-3 Gene Silencing for Inhibiting Apoptosis in Insulinoma Cells and Human Islets".

Concerns on mercury emissions may foster new $500 million per year industry

Proposed government regulations limiting emissions of mercury from electricity-generating stations may foster development of a new half-billion-dollar per year industry offering technology for removing mercury from power plant smokestacks, according to an article scheduled for the November 24 issue of Chemical & Engineering News, ACS' weekly newsmagazine.

In the article, C&EN Senior Correspondent Marc Reisch points out that mercury is a toxic metal that can cause nerve damage and birth defects in humans. The nation's 1,100 coal-burning power plants spew 48 tons of mercury into the air each year, posing an invisible but serious public health hazard, the article notes.

To reduce that threat, federal regulators have proposed new restrictions on mercury emissions from electric power plants. When they do go into effect, suppliers of environmental technologies designed to reduce mercury emissions expect a future market of $500 million a year or more. One of the most promising mercury removal technologies is activated carbon, which can reduce mercury emissions by 90 percent or more, according to the article. But new and improved technologies for mercury removal are under development, including catalysts made of gold, platinum, or titanium dioxide. The payoff could mean a sizable new source of sales and income for some suppliers, the article notes.

Chemical & Engineering News: "Getting Rid of Mercury".

Toward a new generation of paper-thin loudspeakers

In research that may redefine ear buds, earphones, stereo loudspeakers, and other devices for producing sound, researchers in China are reporting development of flexible loudspeakers thinner than paper that might be inserted into the ears with an index finger or attached to clothing, walls, or windows. Their report on what may be the world's thinnest loudspeakers, made from transparent carbon nanotube films, is scheduled for the December 10 issue of ACS' Nano Letters, a monthly journal.

Kaili Jiang, Shoushan Fan, and colleagues note that most of today's loudspeakers are relatively bulky, complex, and inflexible, consisting of a permanent magnet fixed to a voice coil and a cone. To meet the growing demand for smaller speakers for portable digital consumer electronics devices, manufacturers need new technology, they say.

The scientists describe the development of super-thin carbon nanotube (CNT) films - 1/1,000th the width of a single human hair - that are capable of transmitting music and other sounds. In laboratory tests, the researchers mounted a thin CNT film onto two electrodes to form a simple loudspeaker. The speaker produced sound with the same excellent quality as conventional loudspeakers, but without magnets and moving components, the researchers say. They also demonstrated that the flexible film could be used just as effectively to play music from an iPod and while pasted to a flexible, waving flag (please see accompanying video of the article).

"These CNT thin film loudspeakers are transparent, flexible, and stretchable, which can be tailored into many shapes and mounted on a variety of insulating surfaces, such as room walls, ceilings, pillars, windows , flags, and clothes without limitations. Furthermore, CNT thin films can also be made into small area devices, such as earphones and buzzers. There is no doubt that more and more applications will be developed as time goes on. This technique might open new applications of and approaches to manufacturing loudspeakers and other acoustic devices."- MTS

Nano Letters: "Flexible, Stretchable, Transparent Carbon Nanotube Thin Film Loudspeakers".

A faster test for the food protein that triggers celiac disease

Researchers in Spain and the United Kingdom are reporting development of a faster test for identifying the food protein that triggers celiac disease, a difficult-to-diagnose digestive disease involving the inability to digest protein called gluten that occurs in wheat, oats, rye, and barley. The finding could help millions of people avoid diarrhea, bloating, and other symptoms that occur when they unknowingly eat foods containing gluten. The study is scheduled for the December 15 issue of Analytical Chemistry, a semi-monthly journal.

In the new report, Alex Fragoso, Ciara O'Sullivan and colleagues note that patients with celiac disease can avoid symptoms by avoiding foods that contain gluten. Doing so can be tricky, however, because gluten may be a hidden ingredient in unsuspected foods, such as soy sauce, canned soups, and licorice candy. Some prepared foods list gluten content on package labels, but identifying its presence remains difficult and time-consuming.

The scientists describe development of a new sensor that detects antibodies to the protein gliadin, a component of gluten. Laboratory tests showed that it is superior to the so-called enzyme-linked immunosorbent assay (ELISA), now the standard test for gliadin. It took the new test barely 90 minutes to detect gliadin in the parts per billion range, compared to 8 hours for the ELISA test. Although both tests were equally accurate, the new sensor would be easier to use at food manufacturing plants, the researchers note. - MTS

Analytical Chemistry: "Electrochemical Immunosensor for Detection of Celiac Disease Toxic Gliadin in Foodstuff".

"Powerhouses" from living cells power new explosives detector

Researchers in Missouri have borrowed the technology that living cells use to produce energy to develop a tiny, self-powered sensor for rapid detection of hidden explosives. The experimental sensor, about the size of a postage stamp, represents the first of its kind to be powered by mitochondria, the microscopic "powerhouses" that provide energy to living cells, the researchers say. Their study is scheduled for the November 26 issue of the weekly Journal of the American Chemical Society.

In the new study, Shelley Minteer, Marguerite Germain, and Robert Arechederra point out that today's explosives detectors are expensive, bulky, and complex. Society needs smaller, cheaper, simpler detection devices, based on technology that perhaps could be incorporated into cell phones and portable digital music players, the researchers suggest.

The scientists describe development of an experimental sensor built from a special biofuel cell, essentially a battery-like device consisting of a thin layer of mitochondria sandwiched between a carbon-based electrode and a gas-permeable electrode. In laboratory studies using nitrobenzene as a test compound, the sensor showed a significant boost in electrical power in the presence of the substance, demonstrating the sensor's potential for detecting TNT and related explosives, the researchers say. - MTS

Journal of the American Chemical Society: "Nitroaromatic Actuation of Mitochondrial Bioelectrocatalysis for Self-Powered Explosive Sensors".

Healthful plant nutrients also found in meat and milk

Counterintuitive as it may seem, those healthful phytoestrogen nutrients that consumers usually associate with fruits and vegetables also exist in foods of animal origin. After all, "phyto" means "plant." Now the first comprehensive study of phytoestrogen content in foods has identified the best sources of these nutrients. The study is scheduled for the November 26 issue of ACS' bi-weekly Journal of Agricultural and Food Chemistry.

In the study, Gunter G. C. Kuhnle, Laure Thomas and colleagues point out that phytoestrogens have garnered increasing attention for their beneficial role in preventing several diseases, including osteoporosis, type-2 diabetes and certain cancers. But much of the scientific research on these compounds has focused on their occurrence in plant-based foods, which has led to an underestimation of actual amounts people consume, the study says.

The researchers analyzed 115 foods of animal origin and found that all food groups studied contained phytoestrogens. Isoflavones - one of the three major classes of these compounds - were considerably higher in soy-based foods. In fact, the amount of phytoestrogens in soy-based infant formula was more than 300 times higher than in normal infant formula. In animal products, phytoestrogens are low when compared to foods containing soy, the paper notes, but the range is similar to that of many commonly consumed vegetables. - JS

Journal of Agricultural and Food Chemistry: "Phytoestrogen Content of Foods of Animal Origin: Dairy Products, Eggs, Meat, Fish, and Seafood".

Toward greener, more energy-efficient buildings

In the face of growing environmental concerns and a renewed interest in energy efficiency, the construction of homes and businesses that emphasize "green" construction materials is on the rise, according to an article scheduled for the November 17 issue of Chemical & Engineering News, ACS' weekly newsmagazine.

In the two-part C&EN cover story, Senior Business Editor Melody Voith notes that while green building materials were once viewed as a trendy environmental statement focusing on natural or recyclable items, these materials now are emerging as practical, high-performance products that also provide energy efficiency. The market for green building products and services was $12 billion in 2007 and experts project it to increase to $60 billion by 2010, the article notes.

Today, a "green building" usually refers to a commercial building or home that has been certified as such by the U.S. Green Building Council (USGBC) for its use of environmentally-friendly materials, among other considerations. The USGBC plans to release updated certification standards in 2009 that emphasize lower energy use and reduced greenhouse gas emissions, the article notes. The U.S. Department of Energy, meanwhile, assists builders in making homes more energy efficient by publishing guideline specifications for insulation, windows, ductwork, appliances, and other items. Says one producer of construction materials, "All of a sudden, green is becoming serious and growing up. It is a huge shift in how buildings are designed and constructed."

Chemical & Engineering News: "High-Performance Buildings".

New insights into thalidomide-birth defect episode

Scientists in Germany have discovered why the medication thalidomide appeared safe in animal tests before going on the market 50 years ago, only to cause perhaps the most extensive outbreak of drug-induced birth defects in medical history. Their study is scheduled for the December 1 edition of ACS' Molecular Pharmaceutics, a bimonthly journal.

Jurgen Knobloch, Ulrich Ruther and colleagues note that more than 10,000 children were born with severe birth defects after drug regulators in Europe approved the medication for treating nausea and vomiting in pregnant women. The drug, never approved for that use in the United States, is available for certain conditions, including multiple myeloma and leprosy. The birth defects outbreak puzzled scientists because pre-marketing tests in lab mice and rats showed no sign of a birth defect risk.

The researchers point out that those animals proved to be resistant to thalidomide's adverse effects, and in the new study they describe discovery of the biochemical basis for that resistance. It involves a key difference between human embryonic cells and those of mice. They found in mice cells advanced antioxidant defenses compared to those in humans and other thalidomide-susceptible species. Therefore, thalidomide is not able to induce the generation of large quantities of damaging free radicals called superoxides in mouse embryonic cells as it does in human embryonic cells (where subsequent cell death is believed to be responsible for birth defects.) - JS

Molecular Pharmaceutics: "Thalidomide Resistance Is Based on the Capacity of the Glutathione-Dependent Antioxidant Defense".

Chemical magic in the mouth

Scientists in Switzerland are reporting that bacteria in the human mouth play a role in creating the distinctive flavors of certain foods. They found that these bacteria actually produce food odors from odorless components of food, allowing people to fully savor fruits and vegetables. Their study is scheduled for the November 12 edition of the ACS bi-weekly Journal of Agricultural and Food Chemistry.

In the study, Christian Starkenmann and colleagues point out that some fruits and vegetables release characteristic odors only after being swallowed. While scientists have previously reported that volatile compounds produced from precursors found in these foods are responsible for this 'retroaromatic' effect, the details of this transformation were not understood.

To fill that knowledge gap, the scientists performed sensory tests on 30 trained panelists to evaluate the odor intensity of volatile compounds � known as thiols � that are released from odorless sulfur compounds found naturally in grapes, onions, and bell peppers. When given samples of the odorless compounds, it took participants 20 to 30 seconds to perceive the aroma of the thiols � and this perception persisted for three minutes. The researchers also determined that the odorless compounds are transformed into the thiols by anaerobic bacteria residing in the mouth � causing the characteristic 'retroaromatic' effect. "The mouth acts as a reactor, adding another dimension to odor perceptions," they explain. However, the authors conclude, it is saliva's ability to trap these free thiols that helps modulate the long-lasting flavors. - KSD

Journal of Agricultural and Food Chemistry:
"Olfactory Perception of Cysteine � S-Conjugates from Fruits and Vegetables".

"Liquid mirror" advance may lead to better eye exams, improved telescopes

Scientists in Canada are reporting progress toward a new type of "liquid mirror" - mirrors made with highly reflective liquids - whose shape can be changed to provide superior optical properties over conventional solid mirrors. The advance could lead to improved instruments for diagnosing eye disease, more powerful telescopes, and other applications, the researchers say. Their research will be described in the November 25 issue of ACS' Chemistry of Materials, a bi-weekly journal.

In the report, Anna Ritcey, Jean-Philippe Dery, and Ermanno Borra note that "liquid mirrors" are not new. Scientists have long recognized that these liquids could provide a low-cost, easy-to-use alternative to solid mirrors for a variety of optical applications while offering the potential for less image distortion. Researchers have recently developed liquid-mirror telescopes that use mercury as the reflective material. Mercury, however, is toxic and the shape of the surface can't be deformed or adjusted.

The scientists describe development of a new type of deformable "liquid mirror" composed of magnetic iron particles, ethylene glycol (a component of automotive antifreeze), and a coating of silver nanoparticles. These materials form a highly reflective mirror whose shape can be changed by adjusting the voltage applied to electromagnets placed below the liquid, allowing the user to fine-tune the mirror's optical properties. In lab studies, the new material showed better reflectivity and stability than current liquid-mirror materials, the scientists say. - MTS

Chemistry of Materials: "Ethylene Glycol Based Ferrofluid for the Fabrication of Magnetically Deformable Liquid Mirrors".

A new way to remove unwanted heparin from blood

Scientists in Poland are reporting development of a potential new way to quickly remove the anticoagulant heparin from patients' blood in order to avoid unwanted side effects that can happen with the current use of that blood thinner. Their new polymer material will be described in the December 8 issue of ACS' Biomacromolecules, a monthly journal.

In the new study, Krzysztof Szczubialka and colleagues point out doctors often want to remove heparin from the blood of patients undergoing surgery or other procedures immediately after completing the procedure. Leaving the heparin alone could lead to unwanted bleeding. Doctors now eliminate heparin by giving patients protamine, a drug that stops heparin's anticoagulant effects. However, they are seeking a better drug because protamine carries a risk of serious side effects.

The scientists describe development of a potential new approach that involves use of microscopic beads of a polymer made from modified chitosan, a material obtained from shellfish. In laboratory tests, the beads reduced concentrations of heparin to nearly zero within 10 minutes. - MTS

Biomacromolecules: "pH-Sensitive Genipin-Cross-Linked Chitosan Microspheres For Heparin Removal".

Terrorism crackdown threatens chemisty hobbyists

Laws and regulations intended to crack down on terrorists, illicit drug manufacture, and other criminal activities are stifling an elite cadre of individuals who pursue chemistry as a hobby and have a home chemistry lab, according to an article scheduled for the Nov. 10 issue of Chemical & Engineering News, ACS' weekly newsmagazine.

In the article, C&EN Associate Editor Bethany Halford notes that having a lab in the basement, garage, or backyard shed was once a rite of passage for scientifically minded kids and a relatively common hobby for science curious-adults. Some of these labs have even produced significant contributions to chemistry, including vulcanized rubber and aniline dyes, the article notes.

Now, in an ongoing battle against bomb-makers and illegal methamphetamine labs, home-based chemistry is increasingly coming under attack. Thousands of people who want to pursue chemistry as a do-it-yourself hobby or home-school lesson must navigate through a maze of federal, state, and local laws that target hazardous substances - or run the risk of fines or laboratory shutdowns, the article notes. "Not all of us are mad bombers or drug makers and we would like to be able to practice our hobby in peace if there's a reasonable way for us to figure out the guidelines," says one authority on hobby chemists.

Chemical & Engineering News: "Underground Science".

Record high performance with new solar cells

Researchers in China and Switzerland are reporting the highest efficiency ever for a promising new genre of solar cells, which many scientists think offer the best hope for making the sun a mainstay source of energy in the future. The photovoltaic cells, called dye-sensitized solar cells or Gr�tzel cells, could expand the use of solar energy for homes, businesses, and other practical applications, the scientists say. Their study is scheduled for the November 13 issue of ACS' The Journal of Physical Chemistry C, a weekly publication.

The research, conducted by Peng Wang and colleagues - who include Michael Gr�tzel, inventor of the first dye-sensitized solar cell - involves photovoltaic cells composed of titanium dioxide and powerful light-harvesting dyes. Gr�tzel cells are less expensive than standard silicon-based solar cells and can be made into flexible sheets or coatings. Although promising, Gr�tzel cells until now have had serious drawbacks. They have not been efficient enough at converting light into electricity. And their performance dropped after relatively short exposures to sunlight.

In the new study, researchers describe lab tests of solar cells made with a new type of ruthenium-based dye that helps boost the light-harvesting ability. The new cells showed efficiencies as high as 10 percent, a record for this type of solar cell. The new cells also showed greater stability at high temperatures than previous formulas, retaining more than 90 percent of their initial output after 1,000 hours in full sunlight. - MTS

The Journal of Physical Chemistry C: "New Efficiency Records for Stable Dye-Sensitized Solar Cells with Low-Volatility and Ionic Liquid Electrolytes".

Tale of two snails reveals secrets about the biochemistry of evolution

Researchers in Spain are reporting deep new insights into how evolution changes the biochemistry of living things, helping them to adapt to new environments. Their study, based on an analysis of proteins produced by two populations of marine snails, reveals chemical differences that give one population a survival-of-the fittest edge for life in its cold, wave-exposed environment. Their report is scheduled for the November 7 issue of ACS' Journal of Proteome Research, a monthly publication.

In the new study, Emilio Rol�n-Alvarez and colleagues note that scientists long have known that animals of the same species can have different physical characteristics enabling them to survive in different habitats. One famous example is the different beak sizes and shapes that evolved in Darwin's finches, enabling the birds to live on different foods in different habitats on the Galapagos Islands. Until now, however, scientists knew little about the invisible biochemical changes behind such adaptations.

To help fill those gaps, the scientists studied two populations of marine snails that live only a few feet apart on the Spanish coast. One group lives on the lower shore, typically submerged in water and protected from large changes in temperature. The other group lives on the upper shore exposed to daily changes in temperature, humidity and other environmental conditions. Tests with mass spectrometry showed major differences in about 12 percent of the proteins in the snail, a subset of proteins that apparently enables the snails to survive in different environmental conditions. - MTS

Journal of Proteome Research: "Proteomic Comparison between Two Marine Snail Ecotypes Reveals Details about the Biochemistry of Adaptation".

Tiny DNA tweezers can catch and release objects on-demand

Researchers in China are reporting development of a new DNA "tweezers" that are the first of their kind capable of grasping and releasing objects on-demand. The microscopic tweezers could have several potential uses, the researchers note. Those include microsurgery, drug and gene delivery for gene therapy, and in the manufacturing of nano-sized circuits for futuristic electronics. Their study is scheduled for the November 12 issue of the weekly Journal of the American Chemical Society.

Zhaoxiang Deng and colleagues note that other scientists have developed tweezers made of DNA, the double helix molecule and chemical blueprint of life. Those tweezers can open and close by responding to complementary chemical components found in DNA's backbone. However, getting the tweezers to grasp and release objects like real tweezers has remained a bioengineering challenge until now.

The scientists describe development of a pair of DNA tweezers composed of four DNA strands - three which act as the "arms." In laboratory studies, the scientists showed that they could grab a piece of target DNA in the arms of the tweezers and release it on-demand using a controlled series of hydrogen bonding and pH changes. The scientists used fluorescent gel imaging to confirm the effectiveness of the tweezers' operation. - MTS

Journal of the American Chemical Society: "Catch and Release: DNA Tweezers that Can Capture, Hold, and Release an Object under Control".

DNA fingerprinting method may thwart false labeling of shark meat

Researchers in Spain are reporting that a new DNA identification method could thwart false labeling of shark species used in various seafood products, including the expensive Chinese delicacy known as shark fin soup. Their study is scheduled for the November 26 issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Maria Blanco, Ricardo Perez-Martin, and Carmen G. Sotelo note that consumption of shark meat appears to be on the rise worldwide, with some seafood companies reportedly having substituted cheaper shark species for more expensive species and incorrectly labeling their products. European Union regulations now require listing the species name on shark products to avoid fraud and to help conserve certain shark species. However, a fast, reliable method for distinguishing between different species of shark remains elusive.

The scientists describe the use of a relatively new technique called forensically informative nucleotide sequencing (FINS), in which DNA isolated from unknown biologic samples is compared to a database of DNA markers from known species. In the new study, the scientists collected DNA markers from nine different commercial seafood samples containing shark meat and compared them to known DNA markers from 23 different shark species. The scientists found that two of the nine shark products analyzed had been labeled with incorrect species names, demonstrating the effectiveness for the FINS method. - MTS

Journal of Agricultural and Food Chemistry: "Identification of Shark Species in Seafood Products by Forensically Informative Nucleotide Sequencing".

Toward a safer, more effective method for preserving museum specimens

Some of the most fascinating creatures ever to inhabit the Earth can be seen today only in the form of preserved museum specimens. Researchers now are reporting progress toward a safer, more effective method of preserving these precious biological specimens in order to prolong their study and enjoyment for future generations, according to an article scheduled for the Nov. 3 issue of Chemical & Engineering News, ACS' weekly newsmagazine.

In the article, C&EN Assistant Editor Carmen Drahl notes that the most widely-used substances for long-term museum conservation are solutions of alcohols, such as ethanol, and formalin, a dilute solution of formaldehyde. Although used for centuries as effective preservatives, these solutions have several disadvantages. For example, alcohol is highly flammable and discolors specimens, while formalin has been linked to cancer in animals and also causes discoloration.

Scientists at the Smithsonian's National Museum of Natural History in Washington, D.C. are now experimenting with a promising new solution to help preserve its prized 24-foot long giant squid specimen. Called "Novec," the transparent solution is a nontoxic, non-flammable hydrofluoroether originally developed by 3M Corporation for electronics industry applications. Novec works by forming a chemical envelope around already preserved specimens, much like repelling water from a car's surface by applying a fresh coat of wax. Novec does not get cloudy over time, and unlike traditional preservatives, it protects specimens from color changes. Thus, the Smithsonian's giant squid has become an ongoing experiment in modern preservation methods. "We're very interested in seeing how it will all turn out," says one researcher.

Chemical & Engineering News: "Seeking an Eternal Solution".