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Book Excerpt: Supergerm Warfare

Dragon's drool, frog's glands and shark's stomachs have all been recruited for the fight against drug-resistant bacteria

As the president of antibody systems, a small, Texasbased biotech company, Terry Fredeking had dedicated himself to the search for peptides and other natural substances in animals, the more exotic the better, that might lead to drugs for resistant pathogens. Michael Zasloff’s discovery had made his work possible; one of Zasloff’s former students was in his employ. Some of his samples—which included parasites from Tasmanian devils, among other odd things—showed promise in vitro, but Fredeking hungered for more. In truth, he was a bit of a showboater, eager to make his name, with the sort of chutzpah that made lab scientists shudder but sometimes got things done. “There’s got to be something bigger than this,” he said one day to one of his consultants, George Stewart, professor of parasitology and immunology at the University of Texas. “What can we do next that’s dangerous, exciting and will advance science?”

 

“How about Komodo dragons?” Stewart suggested.

 

“Komodo dragons?” Fredeking echoed. “What in the heck are they?”

 

Stewart explained that the world’s largest lizard, formally known as Varanus komodoensis, was justly famous for being one of a handful of predators big and fearless enough to prey on human beings on a somewhat regular basis. In fact, humans were by no means its largest prey: full-grown Komodos were known to bring down 2,000-pound water buffalo. Found only on the Indonesian islands of Komodo, Flores and Rinca, the dragons were descendants of mososaurs, massive aquatic reptiles that roamed the seas 100 million years ago. Though the Komodo dragon did often hunt down and devour its prey, it also had a craftier method of killing that hinted at the presence of antibiotic peptides. A stealth hunter, the dragon lay in wait for sambar deer, crab-eating macaque monkeys and other mammals of its habitat, then lunged for the abdomen of its passing prey with toothy jaws as strong as a crocodile’s. Almost always, its wounded victims escaped, because the dragons, many of them heavier than a fat, six-foot-tall man, could run only in short bursts. But because the dragons often feasted on rotting carcasses, their jaws teemed with virulent bacteria. Within 72 hours of being bitten by the great lizard, animals would die of bloodstream infections brought on by these bacteria. Eventually the dragon would come lumbering over to take his meal at last.

 

Both because of its lethal saliva, and because the dragon ate carrion teeming with more bacteria, zoologists had long wondered what made the dragons immune to all these pathogens. Whatever it was had to be really powerful, because of an evolutionary oddity about the dragon’s teeth. Razor-sharp as they were, and serrated like a shark’s, the dragon’s teeth were actually covered by its gums. When it snapped its jaws shut on its prey, the teeth cut through the gums. The dragon’s lethal saliva, then, had access to its bloodstream. Yet the Komodo remained uninfected. “In all likelihood,” Stewart finished, “the dragon’s bacteria has been battling with its immune system for millions of years, with both sides getting stronger and stronger over time to keep each other in balance.”

 

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