Tardigrades are famend for his or her skill to resist excessive environments – now we all know how they do it. Tiny molecular sensors of their cells can detect after they produce too many damaging molecules known as free radicals, triggering a dormant state.

Generally known as water bears, tardigrades are eight-legged, microscopic invertebrates that may be discovered all over the world. In antagonistic circumstances, similar to freezing temperatures or intense radiation, the critters shrivel up right into a dry ball known as a tun and enter a state of deep hibernation.

“Tardigrades don’t thrive beneath excessive circumstances, however they’ll overwinter them,” says Derrick Kolling at Marshall College in West Virginia. “We needed to grasp how they’re ready to enter that.”

To analyze, Kolling and his colleagues uncovered tardigrades to excessive ranges of hydrogen peroxide, sugar or salt, or −80°C (−112°F) temperatures to induce tuns. Because of these stresses, the tardigrades produce dangerous, extremely reactive molecules known as oxygen free radicals.

The free radicals then go on to react with different molecules, says crew member Leslie Hicks on the College of North Carolina at Chapel Hill. Crucially, the crew discovered that the free radicals oxidise an amino acid known as cysteine, one of many constructing blocks of proteins within the physique. These reactions trigger proteins to vary their construction and performance, signalling the onset of the dormant state.

In experiments the place cysteine oxidation was prevented, the tardigrades weren’t capable of enter a tun state. “Cysteine acts like a type of regulatory sensor,” says Hicks. “It permits tardigrades to really feel their surroundings and react to emphasize.”

When circumstances improved, the crew discovered that cysteine was now not oxidised, which informed the tardigrades to get up from their tuns.

“Whether or not it is a universally conserved safety mechanism and whether or not that is conserved throughout tardigrade species are actually necessary questions,” says Hicks. The solutions could assist us higher perceive the ageing course of and even how one can obtain long-term house journey, she says.