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Archive - Jul 15, 2009

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Genome of Schistosomiasis Parasite Sequenced

Scientists have sequenced the genome of the parasitic flatworm (Schistosoma mansoni) that causes intestinal schistosomiasis (also called snail fever), a devastating tropical disease that afflicts more than 200 million people in the developing world. "We have used state-of-the-art genetic and computational approaches to decipher the genome of this pathogen and to facilitate drug discovery," said Dr. Najib El-Sayed, senior author of the paper. "Many promising leads for drug development targets have emerged." Schistosomiasis is one of several neglected tropical diseases prevalent across much of Africa, Asia, and South America and affects mainly poor populations living in areas where water is unsafe, sanitation inadequate, and basic health care unavailable. It impacts adults’ and children's capacity to work and learn, and often leads to death. With knowledge of this parasite's genome sequence, scientists will now possibly be able to develop much-needed new treatments for schistosomiasis, for which a vaccine does not yet exist. The drug commonly used to treat this parasitic infection does not prevent re-infection, and there are growing reports of drug resistance and treatment failures. The term “snail fever” comes from part of the S. mansoni parasite’s complex life cycle. The parasite's eggs hatch in water, enter into snail hosts, and then travel to human hosts through contaminated water sources, such as bathing and swimming areas. The mature worm grows in the human blood vessel system, depositing eggs around the bladder or intestines, which triggers the formation of excess connective tissue in those regions. The parasite's eggs are passed to the liver or exit through the urine or feces, continuing the cycle of infection. The genome sequencing of S.

Citrus Chemical Prevents Obesity in Mice

Researchers have reported that a particular flavonoid (naringenin) derived from citrus fruit shows promise for preventing weight gain and other signs of metabolic syndrome, which can lead to type 2 diabetes and increased risk of cardiovascular disease. Metabolic syndrome is characterized by a group of metabolic risk factors present in one person. These risk factors include abdominal obesity, blood fat disorders, elevated blood pressure, and insulin resistance or glucose intolerance. In the current study, one group of mice was fed a high-fat (western) diet to induce the symptoms of metabolic syndrome. A second group was fed the exact same diet and treated with naringenin. Naringenin corrected the elevations in triglyceride and cholesterol, prevented the development of insulin resistance, and completely normalized glucose metabolism. The researchers found that naringenin worked by genetically reprogramming the liver to burn up excess fat, rather than store it. "Furthermore, the marked obesity that develops in these mice was completely prevented by naringenin," said Dr. Murray Huff, senior author of the study. "What was unique about the study was that the effects were independent of caloric intake, meaning the mice ate exactly the same amount of food and the same amount of fat. There was no suppression of appetite or decreased food intake, which are often the basis of strategies to reduce weight gain and its metabolic consequences,” Dr. Huff said.

Animal Evidence That Dietary Supplement May Help Prevent, Treat Cataracts

New evidence, obtained in a rat model, supports earlier suggestions that the dietary supplement carnosine might be effective in preventing and treating cataracts. Cataracts are a clouding of the lens of the eye and are a leading cause of vision loss worldwide. Cataracts develop when the main structural protein in the lens, alpha-crystallin, forms abnormal clumps. The clumps make the lens cloudy and impair vision. Previous studies had hinted that carnosine might help block the formation of these clumps. In the current work, scientists from the University of Catania in Italy, and colleagues, exposed tissue cultures of healthy rat lenses to either guanidine, a substance known to induce the formation of cataracts, or to a combination of guanidine and carnosine. The guanidine lenses became completely cloudy, while the guanidine/carnosine lenses developed 50 to 60 percent less cloudiness. Carnosine also restored most of the clarity to clouded lenses. The results demonstrate the potential of using carnosine for preventing and treating cataracts, the scientists said. The study is scheduled to be published in the July 28 edition of Biochemistry. [Press release]