Shark Bites Microbe

SCIENTISTS HAVE LONG WONDERED WHY SHARKS never seem to get sick. Despite a relatively primitive immune system, they almost never get infected after suffering wounds, and they seem to be cancer-free. Now a team of scientists, working with dogfish taken from the Gulf of Maine, think they may have the answer: a powerful antibiotic found in virtually every cell of the shark's body. The new compound, a chemical cousin of cholesterol, does not belong to any known class of antibiotics, according to a report published by the National Academy of Sciences. But it is surprisingly effective against a broad range of microbes, including fungi, bacteria and parasites. A synthetic version of the dogfish drug is now being tested against a variety of human diseases.