A Healing Bite

By Jennifer S. Holland
2/4/2013 10:08:42 AM

Photo from the February 2013 edition of National Geographic

All content for this article is from the February issue of National Geographic magazine. To see the rest of the photo gallery, click here. To read the rest of the article, click here.

"Venom-the stuff that drips from the fangs and stingers of creatures lurking on the hiking trail or hiding in the cellar or under the woodpile-is nature's most efficient killer. Venom is exquisitely honed to stop a body in its tracks. The complex soup swirls with toxic proteins and peptides-short strings of amino acids similar to proteins. The molecules may have different targets and effects, but they work synergistically for the mightiest punch. Some go for the nervous system, paralyzing by blocking messages between nerves and muscle. Some eat away at molecules so that cells and tissues collapse. Venom can kill by clotting blood and stopping the heart or by preventing clotting and triggering a killer bleed.

Venom from snakes like the Jameson's mamba, seen here in Cameroon, may soon combat heart disease. © Mattias Klum /National Geographic

All venom is multifaceted and multitasking. (The difference between venom and poison is that venom is injected, or dibbled, into victims by way of specialized body parts, and poison is ingested.) Dozens, even hundreds, of toxins can be delivered in a single bite, some with redundant jobs and others with unique ones. In the evolutionary arms race between predator and prey, weapons and defenses are constantly tweaked. Drastically potent concoctions can result: Imagine administering poison to an adversary, then jabbing him with a knife, then finishing him off with a bullet to the head. That's venom at work.

Venom expert Zoltan Takacs grabs a yellow-lipped sea krait in Fijian waters. This snake's toxic bite causes paralysis, which keeps its strong and speedy eel prey from escaping. © Mattias Klum /National Geographic

Ironically, the properties that make venom deadly are also what make it so valuable for medicine. Many venom toxins target the same molecules that need to be controlled to treat diseases. Venom works fast and is highly specific. Its active components-those peptides and proteins, working as toxins and enzymes-target particular molecules, fitting into them like keys into locks. Most medicines work the same way, fitting into and controlling molecular locks to thwart ill effects. It's a challenge to find the toxin that hits only a certain target, but already top medicines for heart disease and diabetes have been derived from venom. New treatments for autoimmune diseases, cancer, and pain could be available within a decade..." This excerpt is from the February issue of National Geographic magazine. Read more.

The hollow fangs of the Jameson's mamba deliver toxins that can lead to respiratory paralysis-and a person's death within hours. © Mattias Klum /National Geographic

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