Surprising Benefits from Bad Biters
Some environmental organizations try to tweak the public conscience by appealing to human self-interest. Take care of Earth's creatures, their messages say, because you never can tell which ones may prove useful.
You've probably seen such advertisements. One of the more popular shows a picture of a handsome little flower, accompanied by text explaining that this endangered Madagascar periwinkle contains compounds useful against a form of leukemia.
Recently, a new green hero has joined the periwinkle. Portraits of the shaggy Pacific yew have begun to appear in the ads. These trees, once seen mostly as trash and nuisances to the lumber industry, are now cherished as the sole source of taxol, a drug useful against some forms of cancer.
The environmental advertisements may feature plants, but their message is more broad: valuable uses may lie hidden in unsuspected places, so saving the creatures of the natural world amounts to a wise investment. Judging by the results of some recent studies, that pragmatic, pro-conservation statement is more accurate than comfortable. It's proved true for some creatures that few people would like to see protected.
Consider, for example, one of the world's most unloved animals: the vampire bat. We speak here of the real vampire bat, not the infamous and fictitious kin of Count Dracula. It lives from South America to Mexico, where it makes a nuisance of itself by nipping hunks out of its prey and lapping up the blood that flows into the gouge. Though not as gruesome as fictional vampires' bloodsucking, the feeding behavior of genuine vampire bats can debilitate livestock and does spread diseases.
People have been trying to wipe out vampire bats for about as long as the two species have shared terrain, but the bats have survived. Which, as it turns out, may offer a definite benefit for people everywhere. Vampire bat saliva contains a potent anticoagulant that helps keep their victims' blood flowing. It also dissolves blood clots, and blood clots are responsible for many heart attacks. Better yet, vampire anticoagulant seems to affect clots without increasing the risk of internal bleeding. And it works swiftly. Researchers working for the pharmaceutical company Merck, Sharp & Dohme found that the active ingredient in vampire-bat saliva opens clogged arteries twice as fast as the present drug of choice for the purpose.
The most popular of the drugs presently used for clot-busting is known as Activase, and it is produced by Genentech, a rival of Merck in developing biotechnology. Genentech scientists responded to the challenge, and think they have found another component in a natural product that, added to their drug, will increase the speed and effectiveness of Activase. The useful component is a protein known as kistrin, and it is also found in the saliva of an animal most people would cheerfully do without: the poisonous Malayan pit viper snake.
In the high-stakes poker game that modern drug development has become, Genentech's bid seems to be, "I'll see your bat spit and raise you one snake spit." It sounds bizarre, and it does conjure images of the adventurousness of drug researchers--imagine collecting vampire drool, much less toxin-laden snake slobber, for a living! Yet the competition is one which all of us, with our fallible hearts, will win.
As will the environmental organizations trying to remind us that we can't predict the creatures that will prove beneficial. Still, though, they're better off sticking with pictures of pretty flowers in their ads. Neither vampire bats nor pit vipers have the same instant appeal.
