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A psychrotolerant non-spore-forming sulfate-reducing bacterium, strain K3S T , was isolated from a Yamal Peninsula cryopeg within permafrost. Strain K3S T grew at subzero temperatures and required Na + for growth. The new bacterium was able to use lactate, formate, pyruvate, fumarate, alanine, ethanol and molecular hydrogen as electron donors in the presence of sulfate, and used sulfate, sulfite, thiosulfate and elemental sulfur as electron acceptors in the presence of lactate. Fe(III)-citrate and Fe(III)-EDTA were reduced without visible growth. Major polar lipids were рhosphatidylserine, рhosphatidylethanolamine, phospholipids, cardiolipin and aminolipid; major cellular fatty acids were C16 : 1ω7, C16 : 0 and C18 : 1ω7; and the predominant isoprenoid quinone was MK-6 (H2). The genomic DNA G+C content was found to be 42.33 mol%. Phylogenetic analysis showed that the closest relative of the new isolate was Desulfovibrio ferrireducens strain 61 T with 97.1 % 16S rRNA gene similarity. In addition, the ANI value between strain K3S T and D. ferrireducens 61 T was 82.1 %. On the basis of the genomic and polyphasic taxonomy data of strain K3S T , we conclude that the strain is a representative of a novel species Desulfovibrio gilichinskyi sp. nov. (=VKM B-2877 T =DSM 100341 T ).

In the present study, we used culture-independent methods to investigate the diversity of methanogenic archaea and their distribution in five permafrost samples collected from a borehole in the Kolyma River Lowland (north-east of Russia). Total DNA was extracted from methane-containing permafrost samples of different age and amplified by PCR. The resulting DNA fragments were cloned. Phylogenetic analysis of the sequences showed the presence of archaea in all studied samples; 60%-95% of sequences belonged to the Euryarchaeota. Methanogenic archaea were novel representatives of Methanosarcinales, Methanomicrobiales, Methanobacteriales and Methanocellales orders. Bathyarchaeota (Miscellaneous Crenarchaeota Group) representatives were found among nonmethanogenic archaea in all the samples studied. The Thaumarchaeota representatives were not found in the upper sample, whereas Woesearchaeota (formerly DHVEG-6) were found in the three deepest samples. Unexpectedly, the greatest diversity of archaea was observed at a depth of 22.3 m, probably due to the availability of the labile organic carbon and/or due to the migration of the microbial cells during the freezing front towards the bottom., (© FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

An anaerobic, saccharolytic bacterial strain designated GLS2T was isolated from aggregates of the psychrotolerant archaeon Methanosarcina mazei strain JL01 isolated from arctic permafrost. Bacterial cells were non-motile, spherical, ovoid and annular with diameter 0.2-4 μm. They were chemoorganoheterotrophs using a wide range of mono-, di- and trisaccharides as carbon and energy sources. The novel isolate required yeast extract and vitamins for growth. The bacteria exhibited resistance to a number of β-lactam antibiotics, rifampicin, streptomycin and vancomycin. Optimum growth was observed between 30 and 34 °C, at pH 6.8-7.5 and with 1-2 g NaCl l- 1. Isolate GLS2T was a strict anaerobe but it tolerated oxygen exposure. On the basis of 16S rRNA gene sequence similarity, strain GLS2T was shown to belong to the genus Sphaerochaeta within the family Spirochaetaceae. Its closest relatives were Sphaerochaeta globosa BuddyT (99.3 % 16S rRNA gene sequence similarity) and Sphaerochaeta pleomorpha GrapesT (95.4 % similarity). The G+C content of DNA was 47.2 mol%. The level of DNA-DNA hybridization between strains GLS2T and BuddyT was 34.7 ± 8.8 %. Major polar lipids were phosphoglycolipids, phospholipids and glycolipids; major fatty acids were C14 : 0, C16 : 0, C16 : 0 3-OH, C16 : 0 dimethyl acetal (DMA), C16 : 1n8 and C16 : 1 DMA; respiratory quinones were not detected. The results of DNA-DNA hybridization, physiological and biochemical tests demonstrated genotypic and phenotypic differentiation of strain GLS2T from the four species of the genus Sphaerochaeta with validly published names that allowed its separation into a new lineage at the species level. Strain GLS2T therefore represents a novel species, for which the name Sphaerochaeta associata sp. nov. is proposed, with the type strain GLS2T ( = DSM 26261T = VKM B-2742T).

A new strain of methanogenic archaea, designated VTT, was isolated from a sample of Spitsbergen permafrost. The cells were nonmotile curved rods, 2.7–5.3 × 0.3 µm. The optimal conditions for growth were 20°C, pH 6.6, and NaCl concentrations 0.03–0.05 M. The H2/CO2 gas mixture was the only substrate used. In the presence of H2/CO2, growth was stimulated by addition of yeast extract or rumen fluid. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strain VTT belonged to the genus Methanobacterium and was most closely related to M. lacus 17A1T (97.02% similarity). Comparison of the sequenced and assembled genome of strain VTT with the genomes of other members of this genus confirmed these results and revealed species-level differences. Our results indicate that this methanogenic isolate belongs to a new species of methanogenic archaea, for which the name Methanobacterium spitsbergense sp. nov. was proposed, with the type strain VTT (=VKM B-3566T = JCM 39284T). [ABSTRACT FROM AUTHOR]

An agreement between the content of amorphous (oxalate-extractable) iron and morphochromatic features of gley attests to the modern activity of gleyzation processes in tundra soils of the Kolyma Lowland, especially within lower parts of gentle and steep slopes. A suprapermafrost reduced gley horizon thawing out in the warmest years is considered a relic of the warmer and wetter stage of soil formation. An integrated analysis of data on the contents of mobile iron and annotated metagenomes indicates that microorganisms affiliated with the Proteobacteria phylum capable of iron reduction predominate in sediments formed under hydromorphic conditions and in modern mineral soil. In laboratory experiments, the process of microbial iron reduction was more active at 5°C than at 20°C. Therefore, it can be assumed that the majority of cultivated communities of iron-reducing bacteria have been adapted to low Arctic temperatures. Under conditions of climate warming and an increase in precipitation, permafrost temperature, and thickness of the seasonally thawed layer, iron reduction processes in the soils rich in the total iron will play an even greater role and create favorable redox conditions for the formation of methane, one of the most important greenhouse gases. [ABSTRACT FROM AUTHOR]

Polysaccharide was revealed in the cytoplasm of spore-forming Clostridium algoriphilum 14D1 = VKM B-2271 = DSM 16153 grown on glucose at 5°C. This polymer was isolated, purified, and identified as a glycogen-like compound based on analysis of its hydrolysis products. The ratio of the polysaccharide to the dry biomass weight did not change in the course of culture growth. Limitation of C. algoriphilum 14D1 growth by nitrogen resulted in a doubling of the polysaccharide/dry biomass ratio. The transition of C. algoriphilum 14D1 cells from optimal conditions into carbon-free medium resulted in utilization of intracellular polysaccharide. The amount of polysaccharide was shown to depend on glucose concentration, type of the carbon substrate, and growth temperature. Future investigations of polysaccharide functions in C. algoriphilum 14D1 cells are discussed. [ABSTRACT FROM AUTHOR]

Hydrogenotrophic and acetoclastic methanogenesis was measured at temperature between 5 and -16.5 °C with H14CO3- and 14CH3CO2- as substrates in Siberian permafrost soils. The rate of methane formation was reduced approximately 2-fold over the temperature range from 5 to -1.8 °C. For the most active sample “a” temperature dependence of CH4, production at negative temperatures was approximately a 100-fold reduction for a range of -1.8 to -16.5 °C for both substrates. According to the Arrhenius equation, the activation energy of methane generation from bicarbonate and acetate for the temperature interval -5 to -16.5 °C was reduced by a factor of 3 and 1.5, respectively, in comparison with the temperatures above zero. In the experiments we tested the geological time series, showing the ability of microorganisms to carry out redox reactions after thousands to millions years of existence in permafrost. From the Climate Change point of view, it is important that the recovered organisms are quickly involved anew in present-day ecological processes after instances of permafrost thawing, and may be vital in nutrient recycling and in the production and consumption of greenhouse gases over a large portion of the Earth’s surface. From an exobiological point of view, the terrestrial permafrost, inhabited by cold adapted microbes and protecting the cells against unfavorable conditions, can be considered as an extraterrestrial model. The methanogenic bacteria and their metabolic end-products found in the Earth’s permafrost provide a range of analogues that could be used in the search for possible ecosystems and potential inhabitants on extraterrestrial cryogenic bodies free of oxygen. [Copyright &y& Elsevier]