Of chubby appearance -and surreal- tardigrades have intrigued researchers for years. And this animal eight legs, whose extension does not exceed the millimeterand which can be found in almost all habitats in the world, has the unsurpassed ability to survive in the most difficult situations. extreme.
Neither the lack of oxygen or water, nor the most scorching or freezing temperatures, nor the radiation from outer space makes an impact on the so-called “water bears,” which survive these conditions by entering a deep state of suspended animation. This aptitude has allowed them to inhabit the Earth for at least 600 million years, and successfully overcome the planet’s five mass extinction events.
As a team of researchers discovered, the key mechanism that contributes to their resilience is a kind of molecular switch which initiates the state of suspended animation. This molecular sensor detects harmful conditions in the environment, and tells the invertebrate when to go dormant and when it can resume normal life.
The study – led by researchers Derrick RJ Kolling of Marshall University and Leslie M. Hicks of the University of North Carolina at Chapel Hill, United States – was published in the journal PLOS ONE.
Experiment
To understand the mechanism, the researchers exposed tardigrades – also popularly known by the endearing nickname of “moss piglets” – at freezing temperatures, high levels of hydrogen peroxide, salt and sugar. In response to these extreme conditions, the animals’ cells produced highly reactive harmful molecules called free radicals.
The free radicals then reacted with other molecules, Hicks told the magazine. New Scientist. Thus, they discovered that free radicals oxidize an amino acid called cysteine, one of the basic components of proteins in the body. These reactions cause proteins to change their structure and function, and this sends a signal to initiate dormancy.
On the other hand, in the experiments in which the researchers used chemicals to block cysteine, water bears failed to detect free radicals and therefore they could not enter the latency state. ““Cysteine acts as a kind of regulatory sensor.”says Hicks. “It allows tardigrades to sense their surroundings and react to stress.”
When external conditions improved, they discovered that cysteine was no longer oxidized, giving the tardigrades the signal to wake up from their state of suspended animation. The result of the research shows that the cysteine oxidation it’s a vital regulatory mechanism which contributes to the remarkable resilience of water bears and helps them survive in ever-changing environments.
The researchers hope that, in the long term, their work will help to better understand the aging process, as well as the impact of space travel on the body, since both are influenced by the damage caused by free radicals to the machinery. vital cell such as DNA and proteins.
