Known to survive in extremely hostile environments, tardigrades are however quite sensitive to radiation. On the other hand, unlike humans and most living beings, these creatures manage the effects of these same radiations very well. How is it possible ?
Tardigrades can suffer from radiation
Tardigrades (or water bears), whose length is between 0.1 and 1 mm, are extremophile animals. In other words, they can withstand extremely hostile environments. Indeed, they are notably capable of surviving extreme temperatures from -272°C to +150°C or at pressures of up to 6,000 bars. Tardigrades also survive in anhydrous environments (with almost no free water), in the vacuum of space, or even in exposure to UV or X-rays. Science also thought that tardigrades were insensitive to radiation. This is actually not the case, as explained by a study published in the journal Current Biology on April 12, 2024.
A team of biologists and chemists from the University of North Carolina at Chapel Hill (United States) has indeed discovered that tardigrades can suffer from the effects of radiation. On the other hand, these creatures are still capable of survive radiation a thousand times more intense than those capable of endangering human life.
A very surprising resilience
Remember that in humans, ionizing radiation can have short-term effects, notably burns, but also long-term effects with the appearance of cancers. In addition, radiation can also generate malformations in unborn children people exposed. More resistant than humans, tardigrades are however not immune. Indeed, researchers discovered that strong radiation could cause these animals to suffer from breaks in the strands of the double helix structure of their DNA.
On the other hand, the enormous difference with humans lies in the fact that tardigrades are capable of repairing this DNA damage. In their organism are found specific proteins : the “damage suppressor” (DSUP) and the “Tardigrade DNA damage response 1” (TDR1). In the event of damage, tardigrades can increase the production of these genes and thus repair the DNA damage while preserving the organization of their chromosomes. However, those responsible for the study did not spare the tardigrades. Indeed, they were bombarded with gamma rays, a high-frequency electromagnetic radiation that is deadly to humans.
One question still remains: when and how did tardigrades learn to be so resilient to radiation? Pending a clear explanation, the discovery could initially help protect other microorganisms from the effects of radiation. Ultimately, it may one day be possible to find a way to protect humans from the harmful effects of cosmic radiation during long-term space travel.
