"Résurrection" et reproduction de tardigrades congelés depuis plus de 30 ans (en anglais)

Des scientifiques ont réussi à ressusciter et à faire se reproduire des tardigrades congelés depuis 1983 ! (en anglais)
Scientists from the Japanese National Institute of Polar Research (NIPR) have reported* that they have retrieved rigid tiny organisms called “tardigrades” collected from moss samples under frozen conditions (-20°C) after 30 years, the longest recorded cryptobiotic duration of survival for tardigrades as animals or eggs.

In the Cryobiology Journal, they explained* that they managed to resuscitate and have them reproduce although they had been frozen since 1983! These tardigrades aka “sea teddy bears” represent an animal sub-phylum close to arthropods. Consisting of about one thousand marine, fresh water and terrestrial species, they are widely represented all over the planet. Highly resistant, once they are kept in a cryptobiosis status, they seem to be indestructible. Cryptobiosis designates the state of an organism whose metabolic activity has come to a sustainable standstill. These stages of dormant life are supposed to help an individual withstand changes occurring within its natural habitat until the conditions are back to normal. Also, they can put up very well with extreme cold conditions. Some of these organisms survived after 24 hours stored at temperatures approaching absolute zero (-273,10°C). In order to do so, tardigrades put themselves into a specific cryptobiosis state called “cryobiosis”. Replacing most of their water with disaccharide (trehalose) and shriveling into a ball, they maintain their cells unchanged. In our case, two individual tardigrades revived after rehydration. One of them even proceeded to reproduction. One rehydrated egg hatched. The present Japanese study extended the known length of long-term survival in tardigrade species considerably.

* Recovery and reproduction of an Antarctic tardigrade retrieved from a moss sample frozen for over 30 years, Tsujimoto M. et al.