National Geographic : 2013 Feb
82 national geographic • february 2013 and skin cancers, as well as glioma, potentially saving or prolonging millions of lives every year. No drugs based on scorpion toxins have yet been approved, but these toxins represent a ver- satile chemical arsenal. One may be a cancer foe, others the basis of cardiac, painkilling, anti- seizure, and antimalarial drugs. There’s even a possible pesticide among them. The cone snail lacks the menacing air of a scorpion, but as I’d learned with Takacs in Fiji, there’s a beast in this beauty. Cone snails have no jaws and no claws. “ They have only a very precarious tether for grabbing their prey,” says Baldomero Olivera, a Conus expert at the Uni- versity of Utah. “So they compensate by hav- ing 50 or more venom components working on different levels.” The fish-eating species Conus purpurascens, one of Olivera’s favorites, uses its extendable, venom-loaded proboscis to essen- tially Taser a fish, immobilizing it in an instant. That gives time for multiple toxins in the venom to disperse and destroy muscle activity. Being stung by a cone snail, Olivera says, “is like being bitten by a cobra and eating fugu at the same time.” (The fugu’s TTX is more than a thou- sand times deadlier to humans than cyanide.) Cone snails, Olivera says, “are like little drug companies that have engineered their own com- pounds to suit their needs.” Conotoxins in snail venom shut down nerve cell processes—which, it turns out, is an effective way to mask pain in people with late-stage cancer. Snail venom pep- tides called conantokins, which have exception- ally precise molecular targets, are being tested with some success against epileptic seizures. Both conotoxins and conantokins may be protective n society Grant Zoltan Takacs’s toxinology research was funded in part by your Society membership.