Biologists from the University of Tokyo found out the cause of invulnerability sluggish

Tiny living organisms, which are called "slow moving" are well known in the scientific community for their insensitivity to external factors. High or low temperature? No problem, sluggish animals survive in incredibly difficult conditions, when even the most resistant microorganisms die.

For the first time, the German pastor I.A. Goetz, calling it "little water bear." These creatures received their modern name in 1777 thanks to the Italian scientist Spallanzani .

The sluggish ones are very small, their body size is 0.1-1.5 mm. The body of these creatures is translucent, consists of four segments and a “head”. Each body segment has a pair of short and thick limbs. Slow-moving at a speed of 2-3 mm per minute. They have no respiratory or circulatory system.
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There are legends about the survival of the Slow Moves, and not only among scientists. These animals can be kept for 20 months (and even more) in liquid oxygen at a temperature of -193 ° C. In liquid helium, they can be about 8 hours, coming to life during thawing. Slow-moving heating to 60-65 ° C is maintained for 10 hours, and up to 100 ° C - for one hour.

Slow pressure withstand about 6000 atmospheres. Moreover, it does not matter in what conditions is a slow-moving - water, perfluorocarbon or carbon dioxide. It does not affect the results of survival. Slow-moving and in a vacuum feel good, withstanding both cosmic radiation and ultraviolet A and B irradiation (wavelength 280-400 nm).

If a group of sluggish individuals is irradiated with radiation (570,000 X-rays), then about 50% of the “subjects” survive. In this case, the lethal dose of radiation for a person is only 500 roentgens.

Slow-roosters withstand extreme dehydration, with the preservation of the proportion of water in 1-2% of body weight. After this creature enters a wet environment, they return to normal.

So why are sluts so hardy?

No other creature is able to withstand something like this without harm to itself. There are creatures that are resistant to cold, there are organisms that are not afraid of heat or vacuum. But to withstand all external factors together, no other living being, except sluggish, is incapable. What is the reason for such a high degree of survival?



The answer to this question was tried to be given by Japanese scientists who sequenced the DNA of the slow-waves. The results of deciphering the genetic material of these creatures gave an answer to some of the questions of interest to biologists in relation to sluggishness for many tens or even hundreds of years. As it turned out, several defense mechanisms work at once, which are due to the presence of special proteins in their bodies.

Japanese researchers have shown that with the introduction of these proteins into human cells, they become more resistant to the effects of X-rays. According to the authors of the study, the DNA chains of human cells with the introduction of one of the proteins, which provide resistance to slow radiation to hard radiation, is damaged by 40% less. “We were very surprised,” says Takuma Hashimoto of the University of Tokyo.

Scientists studied only one of the slug species, Ramazzottius varieornatus, which is one of the most resistant to external factors. In the body of this species of slug species, scientists have found a protein designated in work as Dsup (Damage Suppressor), which reduces the level of negative influence of external factors on the organism of these creatures.

Dsup, according to the researchers, is a DNA-associated protein that protects the chains and improves the resistance to radioactive radiation in the cell. Dsup works best with hard radiation. “X-ray resistance is a side effect of the slug mechanism for extreme dehydration,” says Takekazu Kunieda, another member of the research team.

To obtain Dsup in sufficient quantities, the corresponding gene was transplanted into the genome of Escherichia coli. And then the protein was transferred to the culture of human cells.

If Dsup could have been introduced into the human body, and not just a cell culture, it would probably make us more resistant to radiation. In the process of “exodus,” one encounters hard cosmic radiation, which represents a significant danger to the life and health of astronauts, therefore this “modification” is important for human civilization in the event of further expansion beyond planet Earth.

The results of the work of Japanese scientists interested in other countries. For example, Ingemar Jönsson from Kristianstad University (Sweden) considers research important for medicine.

The study also adds fuel to the fire of the discussion of a large number of third-party genes in the sluggish genotype. Previously it was thought that the percentage of such genes obtained by slow moving from third-party species was about 20%. Japanese scientists claim that this result is incorrect, in fact, the number of third-party genes for slow-moving animals is approximately 2% of the total number of genes in the genotype of these creatures. And the result obtained earlier is an error resulting from contamination of a sample of genetic material.


1.2% - 2% of third-party genes - a completely normal result not only for sluggish, but also for most other living organisms. Some of the defense mechanisms of the species Ramazzottius varieornatus are actually derived from other creatures. But the most part nevertheless has arisen as a result of evolution, all this “achievement” of the slow-moving ducts themselves.

The fact that these creatures are extremely resistant to negative external factors is not the result of obtaining third-party genes, but truly evolutionary acquisitions, as the Japanese claim. They published the results of their research in the authoritative publication Nature Communications .

Japanese scientists claim that the species Ramazzottius varieornatus (and possibly other slug species) simply does not have genes that include the body’s response to stress. For example, when there is a shortage of water, most living things start the process of cell death. A similar situation is observed in the absence of the required amount of nutrients or the impact of other negative factors. Tikhohodok nothing. They simply “do not understand” that the environment threatens their existence if adverse conditions occur.