GabyTardigrades, also known as water bears, are truly the most indestructible creatures on Earth. These microscopic animals, measuring between 0.05 and 1.4 mm in length and moving on eight short legs, seem capable of withstanding anything and emerging unscathed. The strategies behind their superhero-like survival are numerous: from a damage-suppressing protein that protects their DNA to a dehydrated state of anabiosis that they enter when external conditions become unbearable. Recently, scientists have uncovered new possibilities for these water bears. A team led by biologist Courtney Clark-Hachtel from the University of North Carolina at Asheville tested tardigrades for their resistance to high doses of radiation. The researchers bombarded the tiny creatures with gamma rays and observed their reactions. “What we saw surprised us. Tardigrades did things we absolutely did not expect,” said biologist Bob Goldstein. According to him, scientists knew that some species of these creatures could withstand ionizing radiation, even doses that are 1,000 times lethal to humans. Researchers believe that this remarkable ability is due to a damage-suppressing protein known as Dsup. However, not all water bears possess it. Thus, scientists hypothesized that there are other survival mechanisms at play, as reported by Science Alert.
How the Research Was Conducted
To uncover this mystery, the team studied the effects of gamma radiation on the tardigrade species Hypsibius exemplaris. They placed the animals in a tabletop irradiator, exposing them to gamma rays produced by the beta decay of cesium-137. Initially, the creatures were subjected to a lower dose within acceptable limits, followed by a significantly higher, lethal dose. To the surprise of the biologists, the Dsup protein did not protect Hypsibius exemplaris from radiation exposure, despite its presence. The DNA of the tiny subjects did suffer considerable damage from the radiation. However, instead of a preventative defense, the tardigrades ramped up the production of DNA repair genes to such an extent that these products became some of the most prevalent in their microscopic bodies. Within a day after the radiation exposure, the water bears had repaired much of the DNA that had been damaged by the radiation. Thus, as the researchers discovered, Hypsibius exemplaris can endure doses of ionizing radiation that would easily obliterate other animals. As Clark-Hachtel summarized, tardigrades exhibit an incredible response to radiation, and this seems to be the secret behind their extreme survival abilities. “Understanding how tardigrades cope with radiation stress could help us generate new ideas for protecting other animals and microorganisms from harmful radiation,” she added. The results of the study were published in the journal Current Biology.
