by Ramachandra Dilip, Sri Shakti Institute of Engineering and Technology (SIET), Coimbatore, India.
Tardigrade also known as water bear are one of the extremophiles which are said to have survived five mass extinction events. This tardigrades species are so stress tolerant that it can survive the vacuum of space, high and low temperatures, and strong doses of ionizing radiations. Ramazzotius varieornatus is one of tardigrade species, which have the genome size of 75 to 800 mbp of DNA, revealed to have about 19000 proteins.The genome is protected by a protein called DSUP, is one kind of a protein found in tardigrades that tend to bind around the DNA helping it to withstand radiation. DSUP protein allows these species to protect its DNA from harmful radiation and it was able to save a human cell line with less than 40% damage. The protein could with stand median lethal dose of 5000 Gy(gammarays), 6200Gy(heavyion) while hydrated animals were able to tolerate only5-10Gy.