Scientists Discover the Secret Behind Water Bear's Indestructibility, Radiation Resistance
A new study from Tokyo University has uncovered the secrets behind the ability of the microscopic animals called tardigrades, commonly known as "water bears," to survive in some of the most extreme environmental conditions.
The study, published in the journal Nature Communications, is considered to be the most comprehensive genome sequence of tardigrade species up to date. It revealed that these microscopic animals have more copies of enzymes and genes responsible for counteracting oxidative stress and DNA repair. Furthermore, water bears also have a certain kind of protein capable of withstanding radiation.
"A striking feature of tardigrades is that they have developed -- and abundantly express -- tardigrade-unique genes, and some of them likely play important roles in tolerance," lead author Professor Takekazu Kunieda, from University of Tokyo, told Gizmodo.
For the study, the researchers conducted a genetic analysis of Ramazzottius variornatus, which is considered to be the toughest and most resilient species of tardigrades. The researchers observed that the genome of tardigrades have more copies of anti-oxidant enzymes and DNA-repair genes than any other animal. The anti-oxidant enzymes help counteract oxidative stress when the water bear is dehydrated, while the DNA-repair genes help in the recovery of damaged DNA.
Furthermore, the researchers were also able to find a certain kind of protein called "Dsup" (short for "damage suppressor") attached to the tardigrade's DNA. These proteins act like a shield that protects the DNA of tardigrades against the harmful effects of radiation, explaining why the water bears are impervious to radiation and survive the vacuum of space.
To test out the protective properties of Dsup, the researchers inserted the protein into laboratory-grown human cells and exposed the modified cells to X-rays. The researchers noted that the Dsup-treated cell suffered 40 percent less damage from the radiation.
The researchers believe that if the Dsup proteins are transplanted to humans, it may improve our radiation tolerance. However, the researchers noted that Dsup proteins only reduce the damage caused by radiation in half, suggesting that there are other mechanisms at work to provide the tardigrades' ability to completely withstand radiation.