抄録
Tardigrades are hydrophilous invertebrates with four pairs of lobopodous legs forming a phylum and inhabit various environments throughout the world. Terrestrial tardigrades lose their body water almost completely and contract their body into a form called as "tun" when the surrounding water disappears. Although the dried tardigrades show no sign of life, they will recover their activity if a drop of water is given. This ametabolic dry state is called "anhydrobiosis". Anhydrobiotic tardigrades are known to tolerate a variety of extreme environments: they can survive a wide range of temperatures from -273℃ to 151℃, vacuum, hydrostatic pressure up to 600 MPa, ionizing radiation (X-rays, y-rays and ultraviolet rays) and chemicals (alcohol and methyl bromide). Tardigrades may provide a useful model system to study extreme environmental biology in the future, although the mechanisms of tolerance to extreme environments remain unknown. We will summarize extraordinary high stress tolerance in tardigrades and discuss the possible mechanism responsible for it.
