How do tardigrades defy death in extreme conditions?

Tardigrade, these small, graceful eight-legged invertebrates, are renowned for their incredible ability to survive extreme conditions. Known as “water bears,” these microorganisms can withstand extreme stresses such as high osmotic pressure, freezing temperatures, and complete dehydration. This resilience is mainly attributed to their ability to enter the nome state “Tune”where their metabolic activity is drastically reduced, allowing them to survive otherwise lethal conditions. Until now, the mechanisms triggering tune formation in tardigrades remained largely unknown. However, a recent study shed light on this mystery.

Central role of reactive oxygen species (ROS).

Extensive research has revealed that tons in tardigrades are regulated by structure Reactive Oxygen Species (ROS). These molecules, often considered harmful byproducts of cellular metabolism, actually play a critical role in cell signaling, especially under stressful conditions. Studies show that tons are formed in response to an increase in ROS in tardigrade cells, which initiates a series of biochemical reactions.

Reversible oxidation of cysteines: a key mechanism

The most surprising aspect of this invention is the role Reversible oxidation of cysteine, a type of amino acid found in proteins. When tardigrades are under stress, the cysteines in their cells undergo oxidation, changing their form and function. This change is reversible, allowing the tardigrades to quickly resume their normal functions once the stress is removed. This mechanism of oxidation and reduction of cysteines is therefore essential for their entry and exit from the tune.

Significant survival through different cryptobiotic states

Research has also explored the ability of tardigrades to survive in different cryptobiotic states, such as Osmobiosis and cryobiosis, in addition to chemobiosis. Studies have shown that tardigrades can be induced to reproducibly enter these states, and that they maintain high survival rates after exiting them. This opens the door for future research to further explore the survival mechanisms of tardigrades under various extreme conditions.

We now know a lot about tardigrades

This discovery marks a turning point in our understanding of cryptobiosis in tardigrades. By identifying reversible cysteine ​​oxidation as a key mechanism in regulating tardigrade survival, scientists have unlocked one of nature’s deepest mysteries. This not only deepens our knowledge of these fascinating organisms but also opens up promising prospects for biomedical and technological applications, drawing on the remarkable resilience of tardigrades.

Source de l'étude : https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0295062