Scientists who have worked in the Arctic Circle for more than a dozen years say that the melting of eternal ice can bring much more problems than previously thought. Under the impenetrable layer of Arctic ice, dozens of ancient viruses can be hidden, awaiting their awakening. This can happen if the permafrost in which they are located subsides.
In 2015, a French group of scientists led by Jean-Michel Clavry and Chantal Abergel discovered Mollivirus sibericum, a virus 30 thousand years old, in the snows of Siberia. Delivery of it to the laboratory and experiments showed that the virus infects the Acanthamoeba amoeba.
In the early 90s, in the ice of the Russian tundra, scientists first discovered mimivirus, initially mistaken for a bacterium. Unlike viruses, mimiviruses have genes for the production of amino acids and complex proteins. A detailed study of the most complex genome (contain up to 1200 genes, for comparison: HIV has only 9) of the mimivirus is still ongoing. Mimiviruses are so large that they can be seen with an ordinary optical microscope. About 0.5 micrometer in size. Mimiviruses occupy an intermediate position between viruses and microbes, mimicking the latter (hence the name).
Recently, some scientists have suggested that these giant viruses can get out into the wild and infect many people. Fortunately, the vast majority of researchers say it sounds more like a 90s horror scenario.
The likelihood of such a scenario is extremely low, according to New York Times science columnist Carl Zimmer, who recently published the book Planet of Viruses, in which he details the known viruses and the diseases they cause. Even unlikely.
“This particular type of virus only affects amoebas. If you are an amoeba, then of course you should be worried,”Zimmer told Business Insider in 2015.
“Not a single pathogen dangerous to humans has yet escaped from the permafrost of Siberia. Of course, this does not exclude the possibility of new viruses emerging in the future, but now living organisms have so many viruses of their own that I would put all these frozen viruses at the very bottom of our list of possible concerns.
The other day, Zimmer, in an email with Business Insider, again raised this topic and added that all samples of these giant viruses were found in laboratory conditions in water samples obtained from collected ice samples. In other words, at the moment viruses still remain frozen and do not move around the Russian tundra, like some microscopic "Frankenstein", killing everything around.
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“They didn't get out on their own. They were carefully defrosted already in laboratory conditions. In my opinion, this is another evidence in favor of the fact that the danger of an outbreak of ancient viruses is extremely low. I would even say unlikely,”Zimmer said.
Be that as it may, the importance of such an ancient find for science is undeniable. Indeed, with the help of these samples, we will be able to better understand the true nature of viruses, which, apparently, can be much more complex than previously thought. Speaking of the same size, these giant viruses turned out to be about 30 times larger than normal ones.
The photo below shows how the Mollivirus sibericum virus looks under a microscope:
In addition to its unusual size, Mollivirus sibericum also differs from common viruses in that it possesses more than 500 separate genes responsible for the production of complex proteins.
“These things are really very interesting and make us think about what viruses really are,” says Zimmer.
From a technical point of view, viruses are considered to be non-living infectious agents (that is, they can only reproduce inside living cells that infect). However, the mimiviruses under consideration today show some of the characteristics inherent in living things - they have a functioning metabolism.
NIKOLAY KHIZHNYAK
