Antarctic permafrost soils have not received as much geocryological and biological study as has been devoted to the ice sheet, though the permafrost is more stable and older and inhabited by more microbes. This makes these soils potentially more informative and a more significant microbial repository than ice sheets. Due to the stability of the subsurface physicochemical regime, Antarctic permafrost is not an extreme environment but a balanced natural one. Up to 10(4) viable cells/g, whose age presumably corresponds to the longevity of the permanently frozen state of the sediments, have been isolated from Antarctic permafrost. Along with the microbes, metabolic by-products are preserved. This presumed natural cryopreservation makes it possible to observe what may be the oldest microbial communities on Earth. Here, we describe the Antarctic permafrost habitat and biodiversity and provide a model for martian ecosystems.

This study describes the biodiversity of the indigenous microbial community in the sodium-chloride water brines (cryopegs) derived from ancient marine sediments and sandwiched within permafrost 100-120,000 years ago after the Arctic Ocean regression. Cryopegs remain liquid at the in situ temperature of -9 to -11 degrees C and make up the only habitat on the Earth that is characterized by permanently subzero temperatures, high salinity, and the absence of external influence during geological time. From these cryopegs, anaerobic and aerobic, spore-less and spore-forming, halotolerant and halophilic, psychrophilic and psychrotrophic bacteria, mycelial fungi and yeast were isolated and their activity was detected below 0 degrees C.

No abstract

No abstract

Out of 36 strains of fungi of the genus Penicillium , some of which were isolated from ancient permafrost, 14 strains synthesized mycophenolic acid (MPA). Maximal (over 500 mg/l) accumulation of MPA in culture liquid was observed in P. brevicompactum strains (VKM F-457, VKM F-477, and VKM F-1150). This was the first study to detect MPA in representatives of the species P. rugulosum ; in three strains of this species , the level of MPA accumulation exceeded 300 mg/l. The time course of the synthesis of MPA by P. rugulosum strain VKM FW-733 was studied. It was shown that the synthesis of this metabolite was dramatically intensified during the stationary growth phase (ten days).