Internetchemie: Chemie Meldungen in dieser Woche

"Snow flea antifreeze protein" could help improve organ preservation

Scientists in Illinois and Pennsylvania are reporting development of a way to make the antifreeze protein that enables billions of Canadian snow fleas to survive frigid winter temperatures. Their laboratory-produced first-of-a-kind proteins could have practical uses in extending the storage life of donor organs and tissues for human transplantation, the researchers indicate in a report scheduled for the July 9 issue of the Journal of the American Chemical Society, a weekly publication.

In the study, Stephen B. H. Kent and colleagues point out that scientists have tried for years to decipher the molecular structure and produce from chemicals in a laboratory the so-called "snow flea antifreeze protein (sfAFP)." Those steps are critical for obtaining larger amounts of the protein, which exists naturally in only minute quantities in snow fleas. The larger synthetic quantities can be used for further research and potential medical and commercial uses, they say.

The researchers made synthetic sfAFP, and showed that it has the same activity as the natural protein. They also produced variants, including one form of sfAFP with a molecular architecture that is the reverse, or "mirror image," of natural sfAFP and different from any other protein found in living things on Earth. The mirror-image form of sfAFP appears less likely to trigger harmful antibodies and more resistant to destruction by natural enzymes, making it potentially more effective than the native form for use in organ and tissue preservation, the scientists note. "Our most significant advance was the use of the two mirror image forms of the protein to determine the previously unknown crystal structure of this unique protein," said Kent. "That is a first in the history of protein X-ray crystallography." - MTS

Journal of the American Chemical Society: "Mirror Image Forms of Snow Flea Antifreeze Protein Prepared by Total Chemical Synthesis Have Identical Antifreeze Activities".

New findings on Mother Earth's earthy scent

That evocative "earthy" scent of the soil returning to life in spring - and nasty earthy tastes and odors in fish and drinking water - actually results from two substances released by soil bacteria. Researchers in Rhode Island now report identifying how one of these substances forms, an understanding that could lead to improvements in the quality of water and food products. Their study, the first substantial research on the topic in 30 years, is scheduled for the July 23 issue of the weekly Journal of the American Chemical Society.

In the new study, David E. Cane and Chieh-Mei Wang point out that these two substances, geosmin and methylisoborneol, are volatile organic substances produced by certain soil bacteria. Although they are not harmful to health, these substances are difficult to remove from food and water products. The researchers recently identified the mechanism by which geosmin forms, but little is known about how methylisoborneol forms, they say.

To find out, the scientists studied the formation of methylisoborneol from Streptomyces coelicolor, a common soil bacterium. They found that that the substance is formed in an assembly line process directed by two recently discovered genes. A better understanding of this process could lead to new ways to prevent the formation of the odor-causing substance and may lead to consumer products with improved taste and smells, the researchers suggest. - MTS

Journal of the American Chemical Society: "Biochemistry and Molecular Genetics of the Biosynthesis of the Earthy Odorant Methylisoborneol in Streptomyces coelicolor".

A new-generation of simpler sensors for detecting disease-causing microbes and toxins

 
Scientists in Singapore are reporting development of a complete, palm-sized sensor that can detect disease-causing microbes, toxins, and other biological threats instantly without the need for an external power source or a computer. The long-awaited device, ideal for remote medical clinics, battlefields, and other sites, represents the next-generation of faster, simpler biosensors, according to a study scheduled for the August 1 issue of ACS' Analytical Chemistry, a semi-monthly journal.

In the new study, Pavel Neuzil and Julien Reboud explain that the new device uses an existing method for detecting DNA, proteins or cells based on their interaction with light shown on the nanostructured surface when these materials come into contact with it. Most existing biosensors of this type require the use of an external power source, a complex and costly analyzer and rely on an external personal computer to report the results.

Their self-contained analyzer relies on simpler components, such as four light-emitting diodes (LEDs) that light up in specific patters to produce test results without a computer, the researchers say. - MTS

Analytical Chemistry:

"Palm-Sized Biodetection System Based on Localized Surface Plasmon Resonance".

Killer Kevlar - clothing that shields from germs

Protective clothing worn by firemen and other emergency workers may soon get a germ-fighting upgrade. Researchers in South Dakota report progress toward the first Kevlar fabrics that can kill a wide range of infectious agents, including bacteria, viruses, and the spores that cause anthrax. Their study is scheduled for the August 6 issue of ACS' Industrial & Engineering Chemistry Research, a bi-weekly journal.

In the new study, Yuyu Sun and Jie Luo point out that Kevlar fabrics are widely used as fire-resistant materials for firefighters, police and emergency medical workers. But amid increased threats of bioterrorism, there's a growing need for new protective clothing that can also provide multiple protection against a wide variety of dangerous microorganisms.

The scientists developed a special process to coat Kevlar samples with acyclic N-Halamine, a potent germ-fighting substance. They then exposed coated and uncoated fabric samples to E. coli, Staphylococcus aureus, Candida tropicalis (a fungus), MS2 virus, and Bacillus subtilis spores (to mimic anthrax). After a short time, large amounts of microorganisms stuck to untreated fabric samples, but the coated fabrics showed little to no adherence of the infectious agents, the researchers say. The coating is long-lasting, can be reactivated, and does not cause any loss of fabric comfort or strength, they add. - MTS

Industrial & Engineering Chemistry Research: "Acyclic N-Halamine Coated Kevlar Fabric Materials: Preparation and Biocidal Functions".

Screening of tiny chemical fragments may pay big dividends in drug discovery

Scientists who develop new drugs are closely following the progress through clinical trials of a cache of drugs developed with counter-intuitive strategy that defies conventional wisdom, according to an article scheduled for the July 21 issue of Chemical & Engineering News.

In the cover story, C&EN Associate Editor Sarah Everts points out that in traditional drug discovery approaches researchers sort through millions of large, full-sized molecules to find promising substances that can bind strongly to their intended biological targets, a strategy called high-throughput screening (HTS). In so-called fragment-based lead discovery (FBLD), researchers instead sort through a few thousand tiny chemical fragments that bind weakly to their targets. After screening, these weakly-binding fragments are then expanded into more potent substances by adding chemical groups or linking a sequence of promising fragments together piece by piece, the article states.

Although no FBLD-based drugs are on the consumer market yet, about 10 are now in clinical trials. But whether the new strategy will be judged successful or not may have to wait until 2011, the earliest year that drugs developed from FBLD techniques will hit the market, the article notes.

Chemical & Engineering News: "Piece by Piece".