Our relationship to food changes as we age. Our metabolisms slow. We start carrying antacids when going out to dinner. Sometimes well even intentionally eat vegetables. But our transformation has nothing on the brown snake, whose venom gradually morphs to accommodate its new eating habits. Researchers described the snakes enviable aging process in the journal Comparative Biochemistry and Physiology, Part C: Toxicology & Pharmacology. Australian brown snakes (genus Pseudonaja) pack some of the most deadly venom in the world. As the authors of the new paper note, brown snakes are also responsible for the majority of medically important human envenomations in Australia. And that’s saying something. To better understand how that venom works, researchers collected samples from adult and juvenile snakes from nine known Pseudonaja species. Then they tested each venoms effect on blood and other substances. Eight out of the nine species showed a distinct change in venom action between the snakes youth and adulthood. Brown snake venom is known for its anticoagulant, or blood clotpreventing, properties, which can lead to deadly strokes in small animals and internal bleeding in humans. But only the grown-ups venom contained anticoagulants. The babies toxic spit had its own power: attacking the nervous system, causing paralysis. The venoms transformation over time is not random, lead author Bryan Fry, of the University of Queensland, says, but a brilliant adaptation to the snakes preferred diet at different stages in its life. Baby brown snakes eat tiny lizards, while adults prefer meatierbut scrappiermammalian fare like rodents. They need a venom that knocks out their opponents fast. “Young brown snakes may produce clinical symptoms like that of a death adder, as they seek out and paralyse sleeping lizards, Fry said in a statement. “Once older, their venom contains toxins that cause devastating interference with blood clotting, causing rodent prey to become immobilised by stroke. Within the adult snakes venom lay another surprise. Scientists knew that brown snake venom worked by converting one blood protein into another, but other snakes do that, too, and their venom isnt as fast-acting. Some other, hidden process, was going on, and Fry and his colleagues found it. “Our team discovered brown snakes are potent in activating Factor VII, another blood-clotting enzyme, which is the missing (dark matter) element of brown snake envenomations, he said. “The feedback loop created by this enzyme would become a venomous vortex and dramatically accelerate the effects upon the blood.” Reminder: Its not that brown snakes want to be responsible for medically important human envenomations. Like sharks and bears, theyd much rather be left to go about their business. So the best thing for you, and them, is to leave them alone.
Metal Floss, 21 May 2017 ;http://mentalfloss.com/ ;