Гидрохимический и микроэлементный состав воды и донных осадков был определен в транзитной зоне смешения подземных и поверхностных вод в термальном источнике Кучигер (Байкальская рифтовая зона). Поступление химических веществ с подземными водами и высокие температуры создают благоприятные и специфические условия для развития микроорганизмов. Изучено таксономическое разнообразие микробного сообщества воды и донных осадков с использованием анализа ампликонов гена 16SрРНК . Проанализировано 107 619 нуклеотидных последовательностей, отнесенных к 211 ОТЕ. В изученных образцах воды и донных осадков доминировали бактерии, представители архей составляли 0,2-3,1 %. В микробных сообществах филум Proteobacteriaявлялся доминирующим. Субдоминантами в изученных образцах являлись филумы Firmicutes, Chloroflexi, Nitrospirae, Acetothermia и Actinobacteria, где их соотношение варьировало в зависимости от биотопа. Характерная особенность микробного сообщества в термальном источнике Кучигер - доминирование хемолитотрофных бактерий. The hydrochemical and microelement composition of water and bot tom sediments was determined in the Kuchiger thermal spring (Baikal rift zone). The entry of chemicals with groundwater and high temperatures create favorable and specific conditions for the development of microorganisms. The taxonomic diversity of the microbial community of water and bottom sediments was studied using the analysis of 16S rRNA gene aplicons. 107619 nucleotide sequences assigned to 211 OTUs were analyzed. In the studied samples of water and bottom sediments, bacteria dominated, representatives of archaea accounted for 0.2-3.1 %. The phylum Proteobacteria dominated in microbial communities. The subdominants in the studied samples were the phyla Firmicutes, Chloroflexi, Nitrospirae, Acetothermia, and Actinobacteria, where their ratio varied depending on the biotope. A characteristic feature of the microbial community in the Kuchiger thermal spring is the dominance of chemolithotrophic bacteria.

The hydrochemical and microelement composition of water and bottom sediments has been determined in the Kuchiger thermal spring (Baikal rift zone). The entry of chemicals with groundwater and high temperatures create favorable and specific conditions for the development of microorganisms. The taxonomic diversity of the microbial community of water and bottom sediments is studied using the analysis of 16S rRNA gene aplicons, and 107 619 nucleotide sequences assigned to 211 operational taxonomic units (OTUs) are analyzed. In the studied samples of water and bottom sediments, bacteria dominate; representatives of archaea account for 0.2–3.1

Институт общей и экспериментальной биологии СО РАН Россия, 670011, г.Улан-Удэ

Аннотация. Изучено таксономическое разнообразие микробного сообщества микроб

The Buryatian horse is an ancient breed and, as an indigenous breed, they have unique adaptive abilities to use scarce pastures, graze in winter, and survive in harsh conditions with minimal human care. In this study, fecal microbiota of Buryatian horses grazing in the warm and cold seasons were investigated using NGS technology on the Illumina MiSeq platform. We hypothesized that the composition of microbial communities in the feces of horses maintained on pasture would change in the different seasons, depending on the grass availability and different plant diets. We conducted microhistological fecal studies of horse diet composition on steppe pasture. The alpha diversity analysis showed horses had a more abundant and diverse gut microbiota in summer. There were significant effects on the beta diversity of microbial families, which were clustered by the warm and cold season in a principal coordinate analysis (PCoA), with 45% of the variation explained by two principal coordinates. This clustering by season was further confirmed by the significant differences observed in the relative abundances of microbial families and genera. The obtained results can serve as an experimental substantiation for further study of the impact of pasture grasses, which have a pharmacological effect, on the diversity of the gut microbiome and horse health.

Аннотация.Из донных осадков содового озера Нухэ-Нур выделены две алкалогалофильные культуры бактерии.На основании анализа последовательности гена 16S рРНК культуры отнесены к родам Alkalimonas и Paenibacillus.Изучена внеклеточная пептидазная активность штаммов.Показано, что секретируемые пептидазы культуры NN22n обладают широкой субстратной специфичностью, тогда как пептидаза культуры NN22s -узкой субстратной специфичностью и гидролизует белки и пара-нитроанилидные субстраты, проявляя максимальную активность по гидролизу L-лейцилn-нитроанилида (LpNa).Культура NN22n продуцирует как эндопептидазы, так и экзопептидазы, тогда как культура NN22s -только экзопептидазы, что свидетельствует об особенности конкретного вида бактерии и его способности

Аннотация.Методом секвенирования гена 16S рРНК изучено разнообразие микробного сообщества в различных биотопах горячего источника Алла.В сообществах воды, микробных матов и осадка выявлены филотипы, принадлежащие к 17 филумам домена Bacteria и 1 -домена Archaea.Видовое богатство и разнообразие микробного сообщества было выше в микробных матах и донных осадках, чем в воде.Особенностью таксономического состава донных осадков является присутствие

The diversity and functional activity of the microbial community of the bottom sediments and water of the thermal alkaline Umkhei Lake (Baikal Rift Zone), which was formed as a result of groundwater discharge, has been studied. The lake water is shown to be thermal hydrocarbonate–sulphate–sodium water of the Kuldur type. Lake sediments are characterized by higher temperatures and greater saturation with microelements. A comparative analysis of the species abundance of the microbial community of water and bottom sediments shows high indices of diversity in all layers of sediments, while the diversity in water is low. An analysis of taxonomic diversity reveals the predominance of the members of Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Chloroflexi phyla in the community of water and bottom sediments. The presence of bacteria with various metabolic pathways of substance and energy transformation in both production and destruction processes is determined. The sequences belonging to the genus Hydrogenophaga (class β-Proteobacteria, phylum Proteobacteria), which is an indicator of the deep geochemical processes of hydrogen production, are found in the bottom layers of sediments. The rates of microbial processes of photosynthesis, dark assimilation of CO2, sulfate reduction, and methanogenesis are determined to characterize the functional activity. The main part of the organic-matter production in water is found to be formed as a result of the activity of chemolithoautotrophic prokaryotes. In the microbial community, the producers synthesize organic matter using volcanogenic carbon dioxide enriched in the heavy isotope (δ13C). An analysis of the rates of terminal processes indicates that sulfate reduction is the main process.

The Badain Jaran desert is located in the western part of Inner Mongolia (China) in the Alashan Highland. The investigated soda-salt lakes combine high pH (more than 9) and mineralization (up to 400 g/dm3), where conditions for the development of an alkali-halophilic microbial community are created. The purpose of our work was to isolate and study pure alkali-halophilic microorganisms in the lakes of the Badain Jaran desert. From the accumulative cultures of the cortex salt and the microbial mats of the lakes of the Badain Jaran desert, pure cultures belonging to the family Bacillaceae (the phylum Firmicutes) were isolated and described. With the help of biochemical methods, the ecological and physiological properties of the isolated bacteria were determined. The isolated bacteria exhibit the properties of alkalophiles and obligate alkalophiles and develop at pH 7–10.5, the optima ranging from 9 to 10. With respect to the concentration of NaCl, the strains showed the properties of obligate halophiles and extreme halophiles. With respect to temperature, the isolated microorganisms are mesophiles growing at 10–50 °C, the optimal growth being at 30–40 °C. With respect to the substrates used, the isolated cultures are noted for extensive metabolic activity and, when in their natural habitats, are supposedly active participants of the destruction of organic matter. To study the hydrochemical indicators of water, the following methods were used: atomic emission spectrometry with inductively coupled plasma, ion chromatography and capillary electrophoresis. As a result, it was found that a sodium cation and anions of carbonate, bicarbonate of chlorine and sulphate dominate in the soda-salt lakes of the Badain Jaran desert in a multicomponent composition. The results obtained broaden the notion of the diversity and ecological significance of bacteria in the extreme natural ecosystems of the Badain Jaran desert. The isolated strains are of interest for biotechnology as producers of enzymes resistant to high pH and mineralization.

Hydrolytic bacteria (in particular, proteolytics) are the primary destructors in hot springs. The proteolytic bacteria are able to secrete enzymes that are active in wide ranges of pH and temperature. The aim of this work was to study the taxonomic composition, the structure of the bacterial microbial mat, and to study the distribution of peptidases in the thermophilic microbial Garga community. For the study, we sampled the microbial mat at a water temperature of 54.2 °C and a pH of 8.3. Hydrochemical analysis of water showed a high content of sulfates, 390 mg/dm3. The microelement composition of water showed that the Garga water had increased concentrations of B, Rb, Li, Ba, Sr. We analyzed the taxonomic diversity of the microbial community in the hot spring Garga at a temperature zone of 54 °C. The structure of the microbial mat is represented by various phylogenetic groups of mesophilic and thermophilic bacteria, with various metabolic and ecological functions. The dominant group in this community was the phylum Firmicutes (64 %). The analysis of the collected metagenomic sequences of the microbial community allowed the detected peptidases in the microbial community in the hot spring Garga to be for the first time systematized and characterized. Comparisons of metagenomic sequences of representative data showed a dominance of serine peptidase class enzymes. Natural peptidases in the investigated microbial community ensure the hydrolysis of biopolymers at the first stages of the destruction of organic matter and may have biotechnological relevance.

In this study the bacterial diversity of thermophilic microbial mats (40 to 65°C) in three alkaline hot springs of the Baikal Rift Zone (BRZ) was determined through pyrosequencing of 16S rRNA gene libraries. Significant diversity of bacterial species was found in the biomats of the hot springs with total number of detected phylotypes of 607. The highest share of the microbial community was represented by the phyla Chloroflexi (Seya Spring, 76.4%), Deinococcus-Thermus (Alla Spring, 45.1%), Nitrospira (Alla Spring, 36.1%), Cyanobacteria (Tsenkher Spring, 33.1%), and Proteobacteria (Tsenkher Spring, 22.6%), but their ratio varied significantly in different springs. A comparison of the biodiversity and composition of microbial communities between hot springs showed a decrease in biodiversity with increasing temperature. A large number of sequences showed a low degree of similarity with cultivated representatives in public databases. Microbial communities showed intensive rates of production and destruction of organic compounds, as revealed by the quantitative assessment of their functional activity.

The goal of the work was to reveal the differences in the structure of microbial communities of Transbaikalia alkaline lakes stemming from the differences in their salinity and hydrochemical parameters. The lakes studied were Verkhnee Beloe (Buryat Republic, Russia), as well as Khilganta, Gorbunka, and Borzinskoe (Transbaikal krai, Russia) with salinity from 12.3 to 430 g/L, which differed in the mineral composition of the sediments and hydrochemical parameters. Lake sediments were found to contain 47 prokaryotic phyla (42 bacterial and 5 archaeal ones). The phyla Proteobacteria, Euryarchaeota, Bacteroides, Chloroflexi, Actinobacteria, and Firmicutes were predominant, comprising over 95% of the classified sequences. Comparative abundance of archaea increased with salinity from below 1% in Lake Verkhnee Beloe to 35% in Lake Borzinskoe. The most numerous bacterial OTUs belonged to gammaproteobacteria of the genus Halomonas (up to 15% of the number of classified sequences). The most numerous archaeal OTUs were identified at the genus level as members of the genera Halorubrum and Halohasta belonging to the family Halorubraceae, which comprises extremely halophilic Euryarchaeota.

Three strains of haloalkaliphilic bacteria were isolated from microbial mats of soda-saline lakes of the Badain Jaran Desert, Inner Mongolia (China). Based on the data on ribosomal phylogeny, they were identified as members of the genus Halomonas. These bacteria were moderate alkaliphiles and extreme halophiles. The peptidases secreted by these bacteria were shown to have narrow substrate specificity. They hydrolyzed proteins and para-nitroanilide substrates and showed maximal activity in the hydrolysis of L-leucyl-p-nitroanilides (LpNA). The maximum activity of the peptidases occurred at alkaline pH values (8–10) and elevated salinity (50–100 g/L); the enzymes were thermostable (up to 50°С). The results of inhibitor analysis and substrate specificity examination of extracellular enzymes indicated them to belong to the class of aminopeptidase-like metallopeptidases.

Alkaline hydrotherms of the Baikal region are extreme aquatic ecosystems characterized by the presence of the specific microbial communities, mats. A study of the carbohydrate composition of the biomass of microbial maths from four hydrothermal waters of the Baikal region (Alla, Garga, Seya, Umkhei) showed the presence of mannitol (1,93–7,25 mg/g, from the dry weight), uronic acids (1,15–15,85 mg/g) and neutral monosaccharides. The latter were galactose (2,02–56,56 mg/g), glucose (2,00–45,96 mg/g), mannose (4,83–78,86 mg/g), xylose (1,18–10,53 mg/g), fucose (0,23–2,40 mg/g), and arabinose and rhamnose as a trace. It is shown that the mats from the studied hydrothermal waters of the Baikal region characterized by the different ratio of carbohydrate groups and a specific monosaccharide composition. A fraction of water-soluble polysaccharides was isolated from the biomass of the microbial mat of Seya hydrotherm. It was a mixture of seven components with molecular masses from 122 to 1700 kDa. The dominant polymer Se-WSPS-07 with a molecular weight 122 kDa was isolated and preliminarily characterized as a heteropolysaccharide containing galactose, glucose, mannose as dominant monosaccharides, and protein (5,92%). It was found that Se-WSPS-07 possesses biological activity demonstrating its perspectiveness for the further study as a therapeutic agent. The chemical characteristics of the carbohydrate components of microbial maths from the alkaline hydrotherms of the Baikal region were realized for the first time.

Pyrosequencing of the 16S rRNA gene fragments was used to investigate the bacterial community of an Alla hot spring microbial mat. The mat community was mainly represented by the members of five phyla: Deinococcus-Thermus, Nitrospirae, Atribacteria (OP9), Proteobacteria, Chloroflexi, and Firmicutes, with other groups responsible for not more than 2% of the total number. From hot springs of the Baikal Rift Zone (Buryatia, Russia), 13 strains of aerobic alkaliphilic thermophilic organotrophic bacteria were isolated, and their morphology, ecology, physiology, and phylogenetic position were studied. Based on analysis of their 16S rRNA gene sequences, the isolates were identified as members of the family Bacillaceae. Strains Al-9-1, Se-1, Ga-1-1, Ga-9-2, and Se-1-10 were assigned to the genus Anoxybacillus; strains Ur-6, Br-2-2, А2, and Um-09m, to the genus Bacillus; strains Gor-10s and Gа-35, to the genus Paenabacillus. Secreted endopeptidases of the isolates were shown to have relatively narrow substrate specificity. The investigated enzymes were characterized by high pH (6.3–11.4) and temperature stability (23–70°C), which makes it possible to carry out organic matter degradation in the environment under variable ecological conditions.