Nearly microscopic and truely ancient the Tardigrades are aka moss piglets or water bears. Discovered back in 1773 they are high resilient organisms just found everywhere. Fossils of them have been dated back to over 500mya. Individual species can survive extreme conditions which are fatal to nearly all known forms of life. They are known to withstand extreme temperature conditions as low as – 272°C and as high as 150°C.
Recently discovered in the clump of moss found in the parking lot in Tsuruoka City, Japan, new species of tardigrades is named Macrobiotus shonaicus. It’s a mix of characteristics form other species with eggs having flexible filaments.
Crush them, freeze them, boil them, dry them out or blast them into space, tardigrades will survive it all and come back for more!
A space mission TARDIS conducted in 2007 showed that they could survive exposure to vacuum in space.
Where it’s completely impossible to imagine life without water for almost all organisms they can survive extreme desiccation. They curl up into dry shell upon drying, a state called ‘tun state’. These amazing creatures can live in tun state for decades reducing their metabolic activity to 0.01% of the normal levels. In 1995 dried tardigrades were brought back to life after 10 years. They have unique anti dehydration proteins called tardigrades specific intrinsically disordered proteins. These proteins are jelly like in water and turn to glass like structures during desiccation protecting all the dehydration sensitive material from damage. They can tolerate ice formation within their cells, by producing chemicals called ice-nucleating agents which help in crystal formation outside the cells hence protecting vital molecules. They are immense pressure resistant too and can survive pressure of 600Megapascals.
They have a protein called Dsup which protects them from radiation and damaging X-rays. Researchers have been able to transfer that resilience to human cells, which suppressed x-ray induced damage by 40%. These findings may help radiation therapy patients. Tardigrada genome holds great genetic treasures and we are just at the beginning of exploring it.
by
Priyadarshini Singh
Department of Zoology
BHU