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.

This study describes brine lenses (cryopegs) found in Siberian permafrost derived from ancient marine sediment layers of the Arctic Ocean. The cryopegs were formed and isolated from sediment ~100,000-120,000 years ago. They remain liquid at the in situ temperature of -10°C as a result of their high salt content (170-300 g/L). [¹⁴C] Glucose is taken up by the cryopeg biomass at -15°C, indicating microbial metabolism at low temperatures in this habitat. Furthermore, aerobic, anaerobic heterotrophs, sulfate reducers, acetogens, and methanogens were detected by most probable number analysis. Two psychrophilic microbes were isolated from the cryopegs, a Clostridium and a Psychrobacter. The closest relatives of each were previously isolated from Antarctica. The cryopeg econiche might serve as a model for extraterrestrial life, and hence is of particular interest to astrobiology.

This study summarizes the findings of our research on the genesis of methane, its content and distribution in permafrost horizons of different age an

Culture-based study of the faecal microbiome in two adult female subjects revealed the presence of two obligately anaerobic, non-spore-forming, rod-shaped, non-motile, Gram-negative bacterial strains that represent novel species. The first strain, designated 627^T, was a fastidious, slow-growing, indole-positive bacterium with a non-fermentative type of metabolism. The strain was characterized by the production of acetic and succinic acids as metabolic end products, the prevalence of iso-C_15 : 0fatty acid and the presence of menaquinones MK-10 and MK-11. The DNA G+C content was found to be 56.6 mol%. The second strain, designated 177^T, was capable of fermenting a rich collection of carbohydrate substrates, producing acetic acid as a terminal product. The strain was indole-negative and resistant to bile. The major cellular fatty acids were iso-C_15 : 0and anteiso-C_15 : 0(in a 1 : 1 ratio) and the predominant menaquinone was MK-11. The DNA G+C content was 37.8 mol%. A phylogenomic analysis of the draft genomes of strains 627^Tand 177^Tplaced these bacteria in the generaAlistipes(familyRikenellaceae) andCoprobacter(familyPorphyromonadaceae), respectively.On the basis of the phenotypic and genotypic properties of strains 627^Tand 177^T, we conclude that these strains from human faeces represent two novel bacterial species, for which the namesAlistipes inopssp. nov. (type strain 627^T = DSM 28863^T = VKM B-2859^T) andCoprobacter secundussp. nov. (type strain 177^T = DSM 28864^T = VKM B-2857^T) are proposed.

A methanogenic archaeon, strain MK4^T, was isolated from ancient permafrost after long-term selective anaerobic cultivation. The cells were rods, 2.0–8.0 μm long and 0.40–0.45 μm wide, and stained Gram-negative. Optimal growth was observed at 28 °C and pH 7.0–7.2 and in 0.05 M NaCl. The isolate used H₂plus CO₂, methylamine plus H₂and methanol plus H₂as sources for growth and methanogenesis. Phylogenetic analysis of the 16S rRNA gene sequence of the strain showed close affinity withMethanobacterium bryantii(similarity >99 % to the type strain). On the basis of the level of DNA–DNA hybridization (62 %) between strain MK4^TandMethanobacterium bryantiiVKM B-1629^Tand phenotypic and phylogenetic differences, strain MK4^Twas assigned to a novel species of the genusMethanobacterium,Methanobacterium veterumsp. nov., with the type strain MK4^T(=DSM 19849^T=VKM B-2440^T).