The tardigrades or water bears are tiny animals, between 0.1 mm and 1.5 mm, and multicellular invertebrates. The cub of water the tardigrade name means "slow walker" is named by Lazzaro Spallanzani in 1777. The tardigrades are eight small legs ending in claws. Their characteristic is to live in different environments around the globe, from polar regions to the equator, preferring mossy areas, such as forests and tundra, as the lichen is their favorite food.
Ingemar Jönsson of the University of Kristiangard in collaboration with ESA, has launched the Tardis (tardigrades in space) to test the resistance of tardigrades. September 14, 2007 embedded in a Soyuz rocket, two species of tardigrades (see nota), among 1150 existing species were exposed to conditions in space. In the words of the article published in Current Biology, ultraviolet radiation, 1000 times higher than on Earth, would have destroyed its chromosomes. But after ten days, the tardigrades for the most part survived. We already knew tardigrades can withstand a huge temperature range of -270 ° C to +150 ° C, vacuum or pressure of a huge ocean hypothetical 60,000 meters or 600 mega Pascal (6 000 bar). Swedish researchers believe that tardigrades in space does not emerge unscathed from their trip because the UV damaged DNA. However, some animals have managed to "repair" to survive. On land, they are also present in the sand, foam roofs wetlands, sediment saline or freshwater. Their life is not really known, however, tardigrades are able to stop their metabolism and become immortal (state cryptobiosis). These qualities make it an amazing super champion resistance animal. In the laboratory, scientists have managed to maintain eight years in a state of cryptobiosis and tardigrades have returned to life. To enter cryptobiosis, tardigrades retract their eight legs and is almost completely dehydrated. They lose more than 99% of their water, replacing it with a sugar they synthesize.
This kind of antifreeze protects its cells. During this period he protects himself in a small ball of wax called microscopic barrel that limits water loss. When favorable conditions return, water covers the Pooh to life. Some insects, frogs and crustaceans are as capable of entering into cryptobiosis tardigrade, but the tardigrade can hold this for thousands of years and wait for warmer conditions for life miraculously recovered. Tardigrades were found in an ice sheet 2,000 years and came back to life. This form of resistance allows it to suspend time, but also to survive extreme temperatures.
But whence comes this exceptional resistance?
Nature does not create living over equipped, compared to their environment, for nothing. How natural selection has done to test these features aliens?
The tardigrade is so resistant to extreme cold, that one wonders why. Since these conditions are absent on the Earth. This oversupply of tardigrade is it due to chance or origins outside our planet?
The tardigrade is still an exceptional animal that could teach us a lot about life in the universe. Therefore, the scientific community shows towards this gifted, interest infinity.
NB: The two species of tardigrades chosen to be tested in space are the species Richtersius coronifer and Milnesium tardigradum. 4 samples of animals, each including about 30 animals and 30 eggs were prepared for Tardis (Tardigrades in space) mission. Because of the loss due to dehydration of the preparation, in the final samples are slightly lower than 30. Samples Richtersius coronifer adults were obtained from a population found in the south of Sweden. The Milnesium tardigradum adults were obtained from a population of laboratory reared in the Department of Zoology (University of Stuttgart), but from a population found in the German countryside.
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Image: Tardigrades, measuring between 0.1 mm and 1.5 mm, are equipped with eight short legs ending in claws. NB: The cryptobiosis refers to a state completely stopped the metabolism of an organism. It is truly a completely inactive state, the animal becomes almost indestructible and immortal.
On land, they are everywhere some is the middle. Tardigrades are able to stop their metabolism and become immortal (state cryptobiosis).
To enter cryptobiosis, tardigrades retract their eight legs and is almost completely dehydrated.
This form of resistance allows it to suspend time, but also to survive extreme conditions.