Monday, April 14, 2008

Antibiotic Alligator: Promising Proteins Lurk in Reptile Blood

Article by Rachel Ehrenberg /
Researchers hunting for new antibiotics might get some aid from gator blood. Scientists are zeroing in on snippets of proteins found in American alligator blood that kill a wide range of disease-causing microbes and bacteria, including the formidable MRSA or methicillin-resistant Staphylococcus aureus.

Previous experiments have revealed that gator blood extract cripples many human pathogens, including E. coli, the herpes simplex virus and some strains of the yeast Candida albicans. The serum's antimicrobial power probably derives from protein bits called peptides. Widespread among reptiles and amphibians, several such germ-fighting peptides have been isolated from the skin of frogs in recent years. Many of these critters live in "sort of nasty places" that are polluted, and gators probably eat all kinds of sick animals, comments Paul Klein, a reptile infectious disease specialist at the University of Florida College of Medicine in Gainesville.

Fierce battles with prey and other gators can leave gaping flesh wounds—but the animals are fairly hardy. These peptides provide a first line of defense—important in the lower vertebrates, who have a slower antibody response than humans, says Klein. "It seems Mother Nature has built in a circulating system of antimicrobial factories that protect the animals while they are waiting to develop the cell-mediated response that we would develop quickly," he says.

Fishing around in the reptile's blood, the scientists identified four or five super-active peptides, reports chemistry doctoral student Lancia Darville of Louisiana State University in Baton Rouge. She collaborated with LSU chemist Kermit Murray and with Mark Merchant of McNeese State University in Lake Charles, La., and presented the work in New Orleans April 6th at a meeting of the American Chemical Society.

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