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Venus has always been one of the priorities of the space research program in Russia. The history of successful investigations of Venus in the Soviet Union is primarily associated with delivering a whole series of spacecraft to it and implementing the first ever landing on its surface. In the last few years, the study of Venus in astrobiological direction has been rapidly developing. To date, a fairly large number of theoretical papers have been published, the main purpose of which is to estimate the possibility of the existence of living organisms on Venus. The most likely ecosystem, in which Earth-type organisms could develop, is considered to be a dense cloud layer of Venus. It is supposed that, in this layer, hypothetical microbial communities could exist in aerosols being a concentrated aqueous solution of sulfuric acid. Microorganisms in such a specific air habitat are to be exposed to several extreme factors at once, the main among which are very low values of pH and water activity. The principal strategies for survival under these conditions should be the availability of effective biochemical mechanisms of resistance to the impact of adverse environmental factors and the use of all possible ways of extracting energy in such an ecosystem to maintain the biomass of organisms at a level for stable reproduction. [ABSTRACT FROM AUTHOR]

Methane fluxes from municipal solid waste landfills in Surgut and Khanty-Mansiysk are assessed in August 2015 by the inverse modeling method. It is revealed that the methane flux values vary from 0.3 to 5.8 g CH/(m hour). The highest value of the methane flux is typical of a landfill that is currently used for the waste disposal and is not covered with the soil layer, whereas the lowest value was obtained for a closed small-capacity landfill covered with soil and vegetation. [ABSTRACT FROM AUTHOR]

Methane production and archaeal community composition were studied in samples from an acidic peat bog incubated at different temperatures and pH values. H2-dependent methanogenesis increased strongly at the lowest pH, 3.8, and Methanobacteriaceae became important except for Methanomicrobiaceae and Methanosarcinaceae. An acidophilic and psychrotolerant Methanobacterium sp. was isolated using H2-plus-CO2-supplemented medium at pH 4.5. [ABSTRACT FROM AUTHOR]

Anaerobic conversion of organic matter leads to the intermediate formation of volatile fatty acids (VFA), primarily butyrate, propionate and acetate. The present investigation examined methanogenesis from the VFA by microbial populations associated with natural and man-made cold habitats. Sites that were investigated included lake sediments, tundra wetland soil, sludge lagoons, manure store and anaerobic reactors operated at 3-9 deg. C. Sharp increases in methanogenesis from VFA were observed as incubation temperatures were increased to 30 deg. C. Low temperatures resulted in significant methane production, and butyrate was identified as an important VFA intermediate formed and degraded during sample incubations. The addition of butyrate and propionate to samples indicated that butyrate is degraded preferentially over propionate. Dilution of samples and, hence, microbial populations led to the accumulation of acetate and hydrogen when butyrate and propionate were degraded. Thus, at low temperatures, a highdensity of hydrogen- and acetate-utilizing methanogens is needed for methanogenesis from VFA to occur. An aggregation of proton-reducing acetogenic bacteria and methanogens accelerates this process. [ABSTRACT FROM AUTHOR]

Abstract The AstroScience Exploration Network (ASEN) is the latest innovative initiative from the Network of Researchers on the Chemical Emergence of Life (NoRCEL). Materializing on the vibrancy of the African continent, recognizing its people as a key asset, and building on specific strategic advantages, ASEN will funnel the appetite for scientific knowledge through an educational hub that paves the way for the Global South to come to the fore in new global endeavors and will eventually help build a variety of career paths in a diversifying economy.

The article shows the compatibility of the concept of thermodynamic inversion (TI) of the origin of life with the theory of stress in (micro)biology. According to the proposed TI concept, the first microorganisms on Earth were formed through an effective (intensified and purposeful) response of organic microsystems to incessant oscillations of physicochemical parameters (i.e., to periodic stress) in a hydrothermal environment. This approach allows us to explain the ability of contemporary microorganisms to respond to stress at the individual and population levels. The ability of microorganisms to effectively react to environmental stress factors is corroborated by a number of molecular and other mechanisms that are described in the article.

Sulfuricurvum kujiense Kodama and Watanabe 2004 is the type species of the monotypic genus Sulfuricurvum, which belongs to the family Helicobacteraceae in the class Epsilonproteobacteria. The species is of interest because it is frequently found in crude oil and oil sands where it utilizes various reduced sulfur compounds such as elemental sulfur, sulfide and thiosulfate as electron donors. Members of the species do not utilize sugars, organic acids or hydrocarbons as carbon and energy sources. This genome sequence represents the type strain of the only species in the genus Sulfuricurvum. The genome, which consists of a circular chromosome of 2,574,824 bp length and four plasmids of 118,585 bp, 71,513 bp, 51,014 bp, and 3,421 bp length, respectively, harboring a total of 2,879 protein-coding and 61 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

Pedobacter saltans Steyn et al. 1998 is one of currently 32 species in the genus Pedobacter within the family Sphingobacteriaceae. The species is of interest for its isolated location in the tree of life. Like other members of the genus P. saltans is heparinolytic. Cells of P. saltans show a peculiar gliding, dancing motility and can be distinguished from other Pedobacter strains by their ability to utilize glycerol and the inability to assimilate D-cellobiose. The genome presented here is only the second completed genome sequence of a type strain from a member of the family Sphingobacteriaceae to be published. The 4,635,236 bp long genome with its 3,854 protein-coding and 67 RNA genes consists of one chromosome, and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

The formation of methane in various ecosystems is due to the functioning of an anaerobic community, which combines trophically different groups of microorganisms. The methanogenic microbial community is a complex biological system, which responds to low temperatures by changes in its trophic structure resulting in redistributing matter flows. The enhanced activity of homoacetogenic bacteria at low temperature plays a significant role in this redistribution. Due to their relatively high growth rates and metabolic versatility, homoacetogens can successfully compete with fermenting bacteria and hydrogenotrophic methanogenic archaea for common substrates. The concentration of hydrogen is an important regulatory factor in the psychroactive methanogenic community. At low temperature methanogenic archaea possessing a higher affinity for hydrogen than homoacetogens provide for interspecies H2 transport in syntrophic reactions of fatty acid decomposition. The formation of a balanced community at low temperature is a longtime process. Cold terrestrial ecosystems are dominated by psychroactive (psychrotolerant) microorganisms, which can grow over a wide range of ambient temperatures.

In most terrestrial ecosystems of boreal and northern climate zones degradation of organic matter with methane production occurs at low temperature. Two psychrophilic methanogenic archaea and four acetogenic bacteria were described until now. Recently, we isolated 12 new strains of methanogenic archaea and 3 strains of acetogenic bacteria from different natural and man-made cold environments including tundra permafrost wet land, sediments of deep lakes, silt of sludge disposal pond, pig and cattle manure digested at 6 degrees C, and an anaerobic EGSB-reactor operated at 9 degrees C. The temperature characteristics of microorganisms isolated from cold environments are discussed. All isolates are able to grow below 10 degrees C, most of them grow at such low temperature as 1 degrees C. The upper temperature limit for most growing at low temperature acetogens is 30 degrees C, and the temperature optima is 20 degrees C and below. Most isolated methanogens have temperature optima around 25 degrees C, and upper temperature limits at 30-40 degrees C. Whether microorganisms able to grow at low temperature are classified as mesophiles, psychrophiles, or psychrotrophs (psychrotolerants) is an issue of this article. We propose to modify the basic temperature definition of anaerobic microorganisms growing at low temperature.

A new psychrophilic, anaerobic, acetogenic bacterium from the tundra wetland soil of Polar Ural is described. The organism fermented H2/CO2, formate, methanol, and several sugars to acetate as the sole end-product. The temperature range for growth was 1-30 degrees C with an optimum at 20 degrees C. The bacterium showed no growth at 32 degrees C. Cells were gram-positive, oval-shaped, flagellated rods 0.7-1.l x 1.1-4.0 microm in size when grown at 1-20 degrees C. At 25-30 degrees C, the cell size increased up to 2-3 x 10-15 microm due to a defect in cell division. The DNA G+C content of the organism was 39.2 mol%. Based upon 16S rDNA analysis and DNA-DNA reassociation studies, the organism was classified in the genus Acetobacterium as a new species, for which the name Acetobacterium tundrae sp. nov. is proposed. The type strain is Z-4493 (=DSM 9173T).