News From The American Chemical Society June 18, 2008

Main Category: Biology / Biochemistry
Also Included In: Public Health;  Nutrition / Diet;  Water - Air Quality / Agriculture
Article Date: 24 Jun 2008 - 5:00 PDT

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Prions are not degraded by conventional sewage treatment processes

Scientists in Wisconsin are reporting in a paper scheduled for the July 1 issue of ACS' Environmental Science & Technology that typical wastewater treatment processes do not degrade prions. Prions, rogue proteins that cause incurable brain infections such as Mad Cow disease and its human equivalent, variant Creutzfeldt-Jakob Disease, are difficult to inactivate, resisting extreme heat, chemical disinfectants, and irradiation. Until now, scientists did not know whether prions entering sewers and septic tanks from slaughterhouses, meatpacking facilities, or private game dressing, could survive and pass through conventional sewage treatment plants.

Joel Pedersen and colleagues used laboratory experiments with simulated wastewater treatment to show that prions can be recovered from wastewater sludge after 20 days, remaining in the "biosolids," a byproduct of sewage treatment sometimes used to fertilize farm fields.

Although emphasizing that prions have never been reported in wastewater treatment plant water or biosolids, the researchers note that existing tests are not sufficiently sensitive to detect the extremely low levels of prions possible in those materials. - AD

ARTICLE: "Persistence of Pathogenic Prion Protein during Simulated Wastewater Treatment Processes" http://dx.doi.org/10.1021/es703186e

CONTACT:
Joel A. Pedersen, Ph.D.
University of Wisconsin
Madison, Wisconsin

New test for more reliable product expiration labels

Beer gets a "skunky" taste. Wine develops an unpleasant flavor termed "light-struck." And exposure to light causes off flavors, colors, and aromas in hundreds of other foods and beverages and decreases shelf life. Now, researchers in Italy report development of a more reliable method for predicting shelf-life that accounts for light sensitivity for the first time and may help consumers choose fresher, tastier food products. Their study is scheduled for the June 25 issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

In the new study, Lara Manzocco and colleagues note that the bright, intense light of retail displays is widely known to cause the formation of off-flavors, loss of nutrients, and color fading in food and beverages. But conventional methods to test the shelf-life of these products focus on the effect of heat and ignore the effect of light, leading to underestimations in shelf-life shown on product expiration labels. A more reliable test is needed, the researchers say.

The scientists exposed a soft drink containing saffron, which contains light-sensitive substances, to different levels of light at increasing temperatures. They found that the beverage grew lighter in color as light intensity increased, confirming that light can cause a dramatic decrease in beverage quality. Based on these observations, the scientists developed a new mathematical model that measures light-sensitivity as well as temperature to provide a more reliable method for predicting shelf-life. - MTS

ARTICLE: Shelf Life Modeling of Photosensitive Food: The Case of Colored Beverages" http://dx.doi.org/10.1021/jf800072u

CONTACT:
Lara Manzocco, Ph.D.
Università di Udine
Udine, Italy

New research reports that 12 million molecules share 143 basic shapes

Chemists in Ohio have discovered that half of all of the known chemical compounds in the world have an amazing similarity in sharing only 143 basic molecular shapes. That sharply limits the number of molecular building blocks that chemists often deploy in efforts to develop new drugs and other products, the researchers say in a study scheduled for the June 20 issue of the bi-weekly ACS' Journal of Organic Chemistry.

Alan H. Lipkus and colleagues note that researchers have known for years that certain features of molecules, such as rings of atoms and the bonds than link them together, appear time after time in hundreds of life-saving medications, food additives, and other widely used products.

Scientists often tend to focus on these well-known types of molecular scaffolding in their quest to select the most promising rings, linkers, and other components for building new drugs while overlooking less familiar structures, the researchers say.

In the new study, they analyzed the chemical frameworks of more than 24 million organic substances found in the ACS' Chemical Abstracts Service (CAS) Registry, the world's most comprehensive database of disclosed molecules. They found that half of the substances could be described by only 143 basic framework shapes. By paying more attention to a multitude of other molecular shapes, chemists might discover an array of useful rings, linkers, and other building blocks for tomorrow's drugs and other medical, commercial, and industrial products, the study concluded. - MTS

ARTICLE: "Structural Diversity of Organic Chemistry. A Scaffold Analysis of the CAS Registry" http://dx.doi.org/10.1021/jo8001276

CONTACT:
Eric Shively
Chemical Abstracts Service
Columbus, Ohio 43210

Building giant 'nanoassemblies' that sense their environment

Researchers in Texas are reporting the design, construction, and assembly of nano-size building blocks into the first giant structures that can sense and respond to changes in environmental conditions. The study, scheduled for the July 9 issue of ACS's Nano Letters, a monthly journal, terms those structures "giant" because they are about the size of a grain of rice - millions of times larger than anything in the submicroscopic realm of the nanoworld.

In the new study, Pulickel M. Ajayan and colleagues point out that such structures are a step toward the development of futuristic nanomachines with practical applications in delivering medicines to patients, labs-on-a-chip, and other products. Until now, scientists have had difficulty in using nanomaterials to build more complex, multifunctional objects needed for those applications.

The researchers describe development of a hybrid nanowire consisting of segments with water-repelling carbon nanotubes on one end and water-attracting metal nanowires on the other end. In laboratory tests, they showed that the nanowires could assemble themselves into larger, more complex structures when placed in water. The structures also sensed and responded to their environment by making movements when exposed to chemicals, magnets, and light. The findings "could lead to the creation of smart materials that are a cornerstone for the development of nanotechnology-based applications," the study notes.

ARTICLE: "Controlled Manipulation of Giant Hybrid Inorganic Nanowire Assemblies" http://dx.doi.org/10.1021/nl080407i

CONTACT:
Pulickel M. Ajayan, Ph.D.
Rice University
Houston, Texas 77251-1892

Chemists develop healthier foods

From carrots to grapefruits to tortillas, researchers worldwide are giving common foods a more nutritious makeover by removing unhealthy substances and adding or enhancing those that may help fight diseases such as cancer and heart disease, according to an article scheduled for the June 23 issue of Chemical & Engineering News. Some of these products could soon appear at a grocery store near you.

In the C&EN cover story, Associate Editor Rachel Petkewich points out that, amid growing consumer interest in leading a healthier lifestyle, scientists are identifying an increasing number of disease-fighting substances in foods and using them to enhance food crops. As evidence for this skyrocketing interest in healthier foods, the article notes that the number of published papers exploring the disease-fighting properties of food components has quintupled since 2003. Scientists have already developed carrots with super-high antioxidant levels. Other foods designed to target cancer, high cholesterol, and other health conditions may soon be on the way.

But creating healthier foods that are still appealing to consumer taste can be tricky, as changing certain food components makes flavor and texture unappetizing. Scientists are now working on creating substances that can boost nutrition without loosing the qualities consumers find appealing.

ARTICLE: "Devising Healthier Foods" http://pubs.acs.org/cen/coverstory/86/8625cover.html

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Article adapted by Medical News Today from original press release.
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The American Chemical Society - the world's largest scientific society - is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

Source: Michael Woods
American Chemical Society