The non-killable water bear uses a fluorescent shield to withstand deadly...

Tardigrades are practically impossible to kill. The microscopic creatures commonly known as “water bears” can tolerate stress that would kill most other organisms. The vacuum of space? No problem for the moss piglets. Extreme pressure and extreme temperatures? Child’s play. Radiation? Pfft. Tardigrades can handle that too. you Maybe he even survived a crash landing on the moon.

A new species, discovered by scientists in a sample of moss grown on a concrete wall in Bengaluru, India, has its own protective superpowers: it can survive ultraviolet (UV) radiation with a “fluorescent shield”.

In a study published Tuesday in the journal Biology Letters, a team of Indian researchers looked at the new species called Paramicrobiotus BLR. The team knew how resilient the creatures are and put them to the test. First, they found that the strain survived germicidal levels of UV radiation within 24 hours – enough to kill another less robust tardigrade species commonly used in experiments known as H. exemplaris.

UV radiation can damage DNA, tear it apart, and cause cells to wither and die. But Paramicrobiotus survived exposure for 30 days.

The researchers write that the next finding was “by chance”. When examining the creatures under UV light, they found that test tubes with Paramicrobiotus BLR glowed or “fluoresced”, while this was not the case with the H. exemplaris tubes. They suspected that the fluorescence could protect the creatures from the dangerous effects of UV radiation.

To test whether the fluorescence is related to the UV shielding, they “homogenized” 300 Paramicrobiotus. That’s a nice, scientific way of saying they mixed 300 creatures together with some water in a tissue grinder. The resulting solution contained the chemicals apparently used by Paramicrobiotus for UV protection.

Scientists added this solution to a plate containing microscopic worms and the H. exemplaris tardigrades to see if it would offer a protective effect. It did. The worms and tardigrades showed higher survival rates after exposure to UV radiation that would normally kill them.

The fluorescent chemical compound Paramicrobiotus BLR, which is used as a protective shield, has yet to be determined. Perhaps other proteins protect against UV radiation – and they would also be present in the homogenized solution, which had a protective effect.

Other known microorganisms use a wide range of tactics to deal with radiation. Bacteria like Deinococcus radiodurans have developed their own methods. A current experiment on the International Space Station showed that the microorganism can quickly repair UV-induced DNA damage and that bacterial pellets can survive exposure to UV radiation for three years. And mushrooms near the Chernobyl nuclear power plant can feed on radiationand converted it into chemical energy.

The research team believes that the tardigrade may have developed its fluorescent protection to counteract the high levels of UV radiation in tropical southern India. While other tardigrades have shown resistance to UV radiation, the mechanism for that protection has remained elusive. As you find out which compounds are responsible for protecting it, new sunscreens or materials that protect against the harmful effects of UV rays may be developed. Maybe we could even coat our spacesuits with tardigrad mud.