Response of methanogens from Siberian permafrost to extreme conditions of terrestrial and extraterrestrial permafrost

The characterization of survival potential of microorganisms which are able to thrive in extreme environments are receiving a great attention in astrobioogical research as driven by the possibility of their existence in extraterrestrial extreme niches. Since ESA mission Mars Express determined water on Mars, fundamental requirement for life, and presence of CH4 in the Martian atmosphere, which could be originated only from active volcanism or from biological sources, it is obviously that microbial life could still exist on Mars, for example in form of subsurface lithoautotrophic ecosystems, which are also exist in permafrost regions on Earth.Present work deals with the resistance investigation of methanogenic archaea from Siberian permafrost to different extreme life conditions of terrestrial or extraterrestrial permafrost: desiccation, temperature extremes, radiation, high salt concentration and simulated Mars conditions. The methanogenic archaea in pure cultures as well as in their natural environment of Siberian permafrost represent high survival potential under these extreme conditions. Significant CH4 formation appeared even by incubation with saturated salt solution (0.02 nmol CH4 h-1 g-1), radiation dose up to 5000 Jm-2 (0.8 nmol CH4 h 1 g 1), desiccation for more than 3 weeks (5.24 nmol CH4 h-1 ml-1), extremely low temperatures of -80°C (5.57 nmol CH4 h-1 ml-1) and Mars simulation for 22 days. Investigation of the survival potential of these high specialized organisms can provide a unique insight to explore the life on the red planet.