Karen Hopkin: What has a head, a foot, and an origin story? No, this is not a weird new superhero. This is a tiny worm called a rotifer, which came back to life after being locked in the Arctic permafrost for about 25,000 years. Its story is recorded in the journal “Contemporary Biology”. [Shmakova et al., A living bdelloid rotifer from 24,000-year-old Arctic permafrost.]
Stas Malavan: So this is a long-term theme of this laboratory.
Hopkin: Stas Malavin of the Institute of Physical Chemistry and Biological Issues in Pushino Social Sciences, Russia. He and his colleagues have spent decades exploring the permafrost in Siberia. They managed to resurrect various interesting creatures. From plant seeds and simple bacteria to dozens of more complex single-celled organisms.
Marathi: We have isolated about 30 or 40 single-celled eukaryotes.
Hopkin: But for some reason, people were not completely stunned by the resurrected amoeba.
Marathi: Yes, they don’t respect them, of course. Rotifers are much better.
Hopkin: Rotifers are better-or at least more interesting-because they are multicellular animals… have a head and body… can eat, crawl around, and make more rotifers. Considering that they are more or less tiny worms, they are actually cute little ones.
Marathi: No, none of them. They are all women. [laugh]
Hopkin: In fact, these little women reproduce asexually… lay eggs and hatch into the next generation of self-reproducing rotifers. So they are easy to grow in the laboratory… although it is not so easy to collect in the lowlands of Siberia.
Marathi: So this place is far away. First we take two or three planes, and then we go to those places by boat or helicopter.
Hopkin: Then they drilled.
Marathi: One or two or more drill holes. In the past, people used the first drill hole as a refrigerator to store subsequent cores.
Hopkin: Nowadays, portable freezers can help them refrigerate samples until they reach the laboratory. There, Malavin and his team cut a small piece from the core center…to prevent potential contamination by modern microbes. Then they put it in a nice warm petri dish.
Marathi: This is called enrichment culture in microbiology. Because these creatures are attached to the particles, they are twisted and folded, and we can’t even see them even with a microscope. So we need to wait until they are reactivated from this crypto-living creature, come out of this permafrost block, start to move and multiply, and so on.
Hopkin: Not every sample will succeed.
Marathi: Usually we can’t see anything. When living things are isolated from this core, this is a relatively rare event. This is also considered to be indirect evidence that it is not pollution. Because you know whether it is like every sample, or every sample will produce some living organisms. Here, it is about one in 20 or even rarer.
Hopkin: In a sample collected in 2015, researchers discovered this small rotifer. They allowed it to reproduce and performed some DNA analysis, and the results showed that although their frozen rotifers are similar to modern varieties, they are not exactly the same.
Marathi: So we think it…a new species of science.
Hopkin: Based on the radiocarbon dating of other organic materials in the permafrost samples, they believe that it is between 20,000 and 30,000 years old.
Marathi: This is an approximate value, but in any case it is two orders of magnitude or three orders of magnitude higher than the known cryptozoal creatures of those animals.
Hopkin: So, the previous record of frozen rotifers is about ten years. This guy…I mean, gal…it was nearby when the mammoth walked on the earth.
Hopkin: Now, the fact that rotifers can be resurrected after thawing is not surprising. Entering a hidden state, even modern rotifers can survive the seasonal changes in the local environment… and more otherworldly attacks.
Marathi: They were actually sent into space, into open space, they survived and so on.
Hopkin: The next step is to study how rotifers can cool down over thousands of years and still maintain their cellular integrity.
Marathi: The main mechanism is actually the animation pause, the metabolism pauses to almost zero or even zero state. So they don’t need energy, almost no energy.
Hopkin: They also produce special proteins that act as antifreeze…or control the formation of ice crystals…These discoveries can enhance the preservation of human tissues and organs.
Marathi: This is why we want to study the proteins that help rotifers survive under these conditions.
Hopkin: When they figure it out…
Marathi: Maybe we will cry, “Yeah! We did it!” Ha. Or something similar.
[The above text is a transcript of this podcast.]