It is virtually impossible kill a tardigrade. You can freeze it, boil it, crush it, zap it with radiation, and deprive it of food and water—for years!—and it will wiggle back to life.
An eight-legged, microscopic creature, the tardigrade is also known as a water bear or moss piglet thanks to its puffy, disarming appearance under a microscope. Observers have described it variously as “tubby,” “an adorable little many-legged bear,” and a “cannon wearing a pair of wrinkled khakis.” (Personally we see an embryonic version of the Ghostbusters’ Stay Puft Marshmallow Man. Either way, it’s adorable.)
Their legendary indestructibility has fascinated scientists for decades. New research sheds light on one of tardigrades’ most remarkable death cheats: the ability to dry out completely for up to 10 years. Previously, scientists believed that tardigrades naturally produce a sugar called trehalose, which allows animals like the wood frog to harden into ice-like statues under extreme cold and then thaw without apparent damage, a process known as vitrification. Yet not all 700 tardigrade species have trehalose, and others possess it only in minute amounts.
Instead, a new paper in the journal Molecular Cell posits that the animals survive desiccation thanks to something called tardigrade-specific intrinsically disordered proteins, or TDPs. As a tardigrade dries, its body sends a signal to the TDPs to vitrify, a process that essentially turns its cells temporarily into glass and suspends the animal’s function. When water is added, the cells return to their normal state.
Vitrification has important implications for humans. Scientists have been studying the process as a potential means of long-term preservation of donated organs, fragile drugs, and vaccines. Down the road, these newly-discovered TDPs could help fix fragile vaccines or medications in a stable state at room temperature so they could be stored and transported without expensive refrigeration, biologist and study co-author Thomas C. Boothby told Wired.
Enthusiasts of cryonics—the practice of long-term cold storing human bodies or brains for eventual reanimation—have embraced vitrification as well. And if it is somehow possible to bring humans back one day, the hardy tardigrade will almost certainly still be around.
Image by Rosa Menkman on Flickr, licensed under CC-BY-2.0. It has been cropped.