A new species of tardigrade confirms a special ability to resist extreme radiation

Tardigrades, also known as ‘water bears’, are small invertebrate animals no larger than a millimeter. They are characterized by a very long list of abilities that continue to fascinate scientists and other specialists; For example, They can survive in extreme environmental conditions and are the most resistant animals to ionizing radiation that we know of. These creatures withstand doses of gamma radiation a thousand times higher than the lethal limit for humans.

Many researchers around the world have been studying them for some time to understand the molecular mechanisms that regulate their incredible abilities. In a study published in the journal Sciencea team of Chinese researchers shared the discovery of Hypsibius henanensis, a hitherto unknown species of tardigrade. By mapping its genome, they identified at least three mechanisms that protect the organism from extreme radiation exposure.

Adaptation to environmental stress

In 2016, a study identified a tardigrade DNA damage suppressor protein, called “Dsup,” that protected genes implanted in human cells from radiation damage. However, it was not yet clear whether this type of protection mechanism was sufficient to explain the ability of these organisms to resist extreme radiation. Since there were other tardigrade species that lacked Dsup, but had the same tolerance to extreme conditions, the researchers suggested that other factors could be at play.

After an investigation lasting six years, the specialists of the report published in Science confirm a sophisticated defense system in the H. henanensis. Specifically, the team observed that exposing specimens of this species to high levels of radiation causes the activation of 285 genes related in some way to the response to ‘environmental stress’. “A factor similar to that of factories that, in times of war, were reused to produce ammunition,” explains Bob Goldstrein, a tardigrade biologist at the University of North Carolina, in an article in Nature.

It turns out that tardigrades do suffer from radiation, but they go away quickly

Two studies reveal new clues about how tardigrades can survive intense radiation. It’s not that it doesn’t damage your DNA; they can simply repair that damage very quickly.

What genes protect them from radiation?

The authors found that the Trid1 protein, whose production in tardigrades is induced by extreme conditions, is capable of accelerating the repair of DNA damage. Likewise, the manufacture of two proteins involved in the functioning of mitochondria; cellular organelles responsible for producing Adenosine Triphosphate (ATP), is particularly stimulated by exposure to radiation. According to specialists, these proteins protect the mitochondria from any destruction.

Finally, Dopa dioxygenase 1, a gene that tardigrades acquire from bacteria through a mechanism known as “horizontal transfer,” encodes the production of betalain molecules.capable of eliminating free radicals that form after exposure to high levels of gamma or authors of the study.

At the moment, these observations have no practical applications, but it is hoped that this type of research will lead to finding new ways to protect astronauts from radiation during upcoming space missions.

Article originally published in WIRED Italy. Adapted by Alondra Flores.