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Rotifers are microscopic multicellular organisms living in freshwater. It is known to freeze (even in liquid nitrogen), boil, dry and hold radiation, and the group has lasted for millions of years without having sex. The humble but very hard bdelloid rotifero has been re-investigated by researchers final examination They found 24,000-year-old Siberian permafrost and found live (or at least resuscitative) rotifers there. Surviving frozen for 24,000 years is a new record for the species.
Rotifers are not the only living organisms that emerge from permafrost or ice. The same researchers behind this latest discovery found an approximately 40,000-year-old baby viable round worms in the permafrost of the region. Ancient mosses, seeds, viruses and bacteria have shown spectacular durability when frozen legal concern whether or not harmful pathogens can be released glaciers and permafrost melt.
Considering that bdelloids are generally a threat to bacteria, algae, and detritus, there is little concern about this particular finding. When they are the most important underlying actors in the food chain, re-emerging rotifers indicate that we should perhaps think about how species that have not been seen for thousands of years can be introduced into modern ecosystems.
The Soil Cryology Laboratory in Pushchino (Russia) has been excavating Siberian permafrost for ten years in search of ancient organisms. The group calculates the age of the organisms found using radiocarbonate from nearby soil samples (evidence has shown that there is no vertical movement in the permafrost layers). For example, last year, researchers “frozen zoo”The estimated 35 viable protists (non-core animals, plants or fungi) were estimated to be between hundreds and thousands of years old.
In the latest discovery, cryological researchers found live bdeloids after working with soil samples for about a month. Among rotifers, bdeloids have a relatively unusual ability to reproduce parthenogenetically, i.e., by cloning, and so they began to make original grains. Although the clones made it difficult to identify ancient parents, this made it easier to investigate the characteristics and behavior of unfrozen strain.
Throughout all previous permafrost studies, there has always been concern about contamination of samples by current organisms. In addition to using techniques designed to prevent this, the team also addressed this issue by examining the DNA in the soil samples, confirming that contamination was very difficult. Phylogenetic analysis also showed that this species did not match modern known rotifers, although a closely related species was found in Belgium.
The team was naturally interested in a better understanding of the freezing process and how these rotifers lasted so long. As a first step, the researchers froze the selection of cloned rotifers at -15 ° C for a week and collected videos of the recycled rotifers.
The researchers found that not all clones survived. Surprisingly, the clones generally tolerated no more frost than contemporary rotifers in the tropics of Iceland, Alaska, Europe, North America, and Asia and Africa. They had a higher frost tolerance than their closest genetic relative, but the difference was marginal.
The researchers found that rotifers can last a relatively slow freezing process (about 45 minutes). This is noteworthy, gradually, because ice crystals formed inside the cells of animals — a development that is often a disaster for living organisms. In fact, anyone in the cryopreservation business is very supportive of the protection mechanisms against it, making the latest discovery particularly appealing from that perspective.
Although the authors are not very good at this business, they plan additional experiments to better understand cryptobiosis – a state of almost completely stopped metabolism that allowed the survival of rotifers. With regard to the research on cryopreservation of larger organisms, the authors suggest that this is more difficult as the organism in question becomes more complex. However, rotifers are among the most complicated species to be cryopreserved to date, with organs such as the brain and gut.
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