SALMONELLA COULD HELP IN ANTHRAX VACCINE
A microbiologist at the University of Texas Health Science Center at San Antonio is exploring the use of salmonella bacteria to deliver vaccines for anthrax and tularemia, two potential biological weapons. Anthrax, a common soil bacterium, is considered the ideal bioterrorism weapon because of the ease with which it can be spread. To spur the body's immune system to knock out these bacteria before they cause damage, Karl Klose, Ph.D. is looking to salmonella, a bacterium that causes food poisoning. "We have crippled the salmonella strain so that it can live in the intestine without causing disease," Klose says. "Next, we want to insert a small piece of anthrax -- the portion that comprises the current injectable vaccine -- into the salmonella." It will be vaccinated into mice and other animals to see if they develop resistance to anthrax or tularemia. The researchers are trying to develop a safer, less expensive and more effective vaccine that would be easy to administer and that would protect people against biowarfare. The U.S. military instituted mandatory anthrax vaccinations for its personnel during the Gulf War. Some in the military objected to the vaccine because it can cause serious reactions after the third or fourth injection, including flu-like symptoms and vision distortions.
DNA BIOCHIP MAY LEAD TO GENETIC SCREENING
A University of Houston scientist has developed a chemical process for building a device that could help doctors predict a patient's response to drugs or screen patients for thousands of genetic mutations and diseases. The DNA chip, is similar to a computer chip, but imbedded with DNA molecules instead of electronic circuitry. It's designed to probe a biological sample for genetic information that indicates whether the person has a genetic predisposition for certain diseases or conditions. "We have put thousands of strands of DNA onto a chip that can screen for the genes linked to breast cancer, cystic fibrosis or prostate cancer," says Xiaolian Gao. "This highly parallel technology allows us to do thousands or tens of thousands of experiments all at once." According to Gao, there are many other biochip technologies available or in development but various devices differ in the technology used to fabricate the chips. The quality, suitability and cost of biochip products need to be significantly improved before most researchers or doctors can afford to use them, she says. "Our novel platform technology will allow scientists to make custom-designed biochips containing not only DNA, but other types of molecules, such as RNA, peptides or libraries of organic molecules," Gao says.
COMPLEX CARBOHYDRATE REGULATES PLANT GROWTH
Twenty-five years ago, Alan Darvill described one of the most complex carbohydrates found in nature -- rhamnogalacturan II or RG-II -- found in plant cell walls. The carbohydrate is found in all higher plants and it requires a host of different proteins to manufacture. Yet for more than two decades, scientists haven't had a clue about its function. "In a sense, we've been on a quest to understand what it's doing in plants ever since we discovered it," says Darvill. In Science, Malcolm O'Neill and colleagues at the University of Georgia say that normal plant growth depends on how RG-II is organized in cell walls and how normal plant growth depends on the ability of RG-II strands to cross-link with boron and form a network in the cell wall matrix. Boron cross-links RG-II strands together in a fishnet-like structure that holds other components in the cell wall in place. "You can think of the cell wall as a bit like reinforced concrete," O'Neill says. "Tiny cellulose fibers are the steel rods and the matrix is the concrete. Only in the cell wall, the concrete has the consistency of jello."
LECITHIN KEEPS CHOLESTEROL FROM BEING ABSORBED
Nutrition researchers at Kansas State University say they have been issued a patent for the finding that the absorption of cholesterol is reduced by another compound in the egg -- lecithin. Sung I. Koo, Yonghzhi Jiang and Sang K. Noh say in nutrition that egg phosphatidylcholine decreases the lymphatic absorption of cholesterol in rats. Many people believe that dietary cholesterol directly contributes to raising blood cholesterol. Since eggs provide about half the dietary cholesterol in a typical Western diet, the public has been advised to limit its egg consumption. Under the experimental conditions using an animal model that closely mimics human physiology, Koo found that a particular egg phospholipid interferes with the absorption of egg cholesterol and markedly lowers its uptake by the intestine. Even though a good amount of cholesterol is consumed when an egg is eaten, much of the cholesterol becomes "unavailable for absorption" in the presence of the phospholipid, Koo says. This may be a reason why so many studies found no association between egg intake and blood cholesterol," he says. "The phospholipid, or lecithin, found in egg markedly inhibits the cholesterol absorption."
(EDITOR: For more information, about BIOCHIP, call 713 743-8192; about CARBOHYDRATE, call 706 583-0913; about LECITHIN, call 785 532-0153.)
