“Steklobloki” protects the animals from drying
To protect from dehydration tardigrades use proteins instead of carbohydrates.
Strange creatures called tardigrades have done in the past year a lot of noise in September in Nature Communications published an article which told the secret of the incredible stability of animals to radiation and desiccation.
Tihohodka. (Photo: jakattack555 / Flickr.com.)
Electron micrograph of six animals. (Photo: Thomas Boothby University of North Carolina, Chapel Hill.)”
That they are able to survive in very difficult conditions, has been known before . First, it turned out that they can be found literally everywhere, from the Himalayan mountains, at an altitude of 6000 m, to ocean depths of 4000 m, from glaciers to hot springs; then it turned out that tardigrades few months can withstand the temperature of liquid oxygen (-193°C) that they can withstand the pressure of 6,000 atmospheres and a dose of radiation, which is more than a thousand times greater than that lethal to humans.
“Water bears” (the second name of animals, common in English literature) sent into outer space, where many of them come back alive and even relatively successfully bred. But how do they do it for a long time remained a mystery, and the authors of the aforementioned article in Nature Communications tried to cover it – they managed to find the genome of animals by some “anti-radiation” gene, whereby the DNA of the animals is relatively easy to tolerate huge doses of hard radiation. (Just in case we will specify that from a molecular point of view, anti-radiation effect is not itself a gene, but encodes a protein.)
Before draining, then it is likely that the animals triggered a different mechanism. In General, for a long time it was thought that they solve the problem by using the carbohydrate trehalose, which the loss of water turns into a glassy mass. Many animals are able to withstand severe prolonged drying, stand it thanks to trehalose, but in the body of the animalcules trehalose proved to be too little to have something to protect. But there is a substitute – in an article in Molecular Cell , researchers from the University of North Carolina at chapel hill and the University of California at Berkeley argue that the animalcules there are special proteins that behave similarly to trehalose.
First, Thomas Boothby (Thomas Boothby) and his colleagues found three different species of animals such genes, whose activity was increased upon loss of water – obviously, the proteins encoded by such genes, must somehow help to survive in difficult conditions. If I turned it off, tardigrades were transferred to the worse: if “protivostojanie” genes transplanted the yeast and bacteria, they have resistance to dehydration increased. Then began to study the properties of the protein itself: it turned out that they support the functioning of enzymes that due to lack of water could stop working, and if you try to dry these proteins, they form a glassy mass, like that which turns out with trehalose.
“Stellabelle” animalcules have been called TDP – acronym stands for “internally disordered Becky of bear animalcules”. Under the internal disorder, then you know that the protein molecules have no stable three-dimensional structure.
We have repeatedly written about the fact that the spatial stacking of the amino acid chain is unique for each protein and determines its functions, however, many proteins have no stable three-dimensional “portrait”, and not just due to their spatial amorphous they can perform quite specific tasks. In this case molecules with a disordered three-dimensional structure during dehydration turn into non-crystalline amorphous mass, which does not allow cell membranes to collapse and explode, thereby maintaining the structure of cells and their organelles.
How such method of protection from desiccation is widespread among animals, will show further research: while the TDP was found only in three species, and there are more than 1200. Perhaps having studied in detail the mechanisms of tolerance of animals, we will be able to learn more about how to cope with the adverse conditions of other living organisms.
According to the materials of The Scientist.