Fermented milk products (FMPs) have numerous health properties, making them an important part of our nutrient budget. Based on traditions, history and geography, there are different preferences and recipes for FMP preparation in distinct regions of the world and Russia in particular. A number of dairy products, both widely occurring and region-specific, were sampled in the households and local markets of the Caucasus republics, Buryatia, Altai, and the Far East and European regions of Russia. The examined FMPs were produced from cow, camel, mare’s or mixed milk, in the traditional way, without adding commercial starter cultures. Lactate and acetate were the major volatile fatty acids (VFA) of the studied FMPs, while succinate, formate, propionate and n-butyrate were present in lower concentrations. Bacterial communities analyzed by 16S rRNA gene V4 fragment amplicon sequencing showed that Firmicutes (Lactococcus, Lactobacillus, Streptococcus, Lentilactobacillus and Leuconostoc) was the predominant phylum in all analyzed FMPs, followed by Proteobacteria (Acetobacter, Klebsiella, Pseudomonas and Citrobacter). Lactobacillus (mainly in beverages) or Lactococcus (mainly in creamy and solid products) were the most abundant community-forming genera in FMPs where raw milk was used and fermentation took place at (or below) room temperature. In turn, representatives of Streptococcus genus dominated the FMPs made from melted or pasteurized milk and fermented at elevated temperatures (such as ryazhenka, cottage cheese and matsoni-like products). It was revealed that the microbial diversity of koumiss, shubat, ryazhenka, matsoni-like products, chegen, sour cream and bryndza varied slightly within each type and correlated well with the same products from other regions and countries. On the other hand, the microbiomes of kefir, prostokvasha, ayran, cottage cheese and suluguni-like cheese were more variable and were shaped by the influence of particular factors linked with regional differences and traditions expressed in specificities in the production process. The microbial diversity of aarts, khurunga, khuruud, tan, ayran and suluguni-like cheese was studied here, to our knowledge, for the first time. The results of this study emphasize the overall similarity of the microbial communities of various FMPs on the one hand, and specificities of regional products on the other. The latter are of particular value in the age of globalization when people have begun searching for new and unusual products and properties. Speaking more specifically, these novel products, with their characteristic communities, might be used for the development of novel microbial associations (i.e., starters) to produce novel products with improved or unique properties.

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.

In the vast expanse of Baikal Siberia, indigenous nomadic animal groups have been conserved, grazing on pastures throughout the year. It is believed that the fecal microbiota of these diverse nomadic animal species is unique to each species and closely tied to their feeding environments. We conducted a pioneering comparative analysis of the taxonomic structure and the diversity of fecal microbiota in indigenous nomadic animals inhabiting Baikal Siberia. Our study encompassed 20 deer, 23 yaks, 24 camels, and 29 sheep, using high-throughput 16S rRNA gene profiling. In the fecal microbiota of these animals, we observed a predominant presence of the phyla Bacillota, Bacteroidota, and Verrucomicrobiota, collectively comprising over 88% of the microbial communities. Moreover, these proportions exhibited variations according to the host species. The unculturable Bacillota UCG-005 and UCG-010 are the key groups for all animals. However, at the genus level, distinctive compositions of fecal microbiota were discernible within each animal group. We identified a total of 37 dominant genera across the fecal samples from these four animal species. Principal component analysis (PCA) and cluster analysis demonstrated that the fecal microbiota composition clustered among individuals of the same animal species. Linear discriminant analysis effect size (LEfSe) indicated that camels exhibited higher abundances of the family Akkermansiaceae and the uncultured clostridial lineage UCG-010, while deer featured Lachnospiraceae; sheep had Ruminococcaceae; and yaks displayed Monoglobaceae, Bacteroidaceae, and methanogenic archaea from the family Methanobacteriaceae as distinctive marker taxa. Our studies showed that the studied nomadic animals feed mainly on plants belonging to the families Poaceae, Cyperaceae, Asteraceae, and Rosaceae. Our research indicated that the identity of the host species and, to a lesser degree, their diets and habitats, significantly shape the composition of fecal microbiota in these studied nomadic ruminant animals.

Soil microbial communities play key roles in biogeochemical cycles and greenhouse gas formation during the decomposition of the released organic matter in the thawing permafrost. The aim of our research was to assess the taxonomic prokaryotic diversity in soil-ecological niches of the Darkhituy-Khaimisan transect during the initial period of soil thawing. We investigated changes in the microbial communities present in the active layer of four sites representing distinct habitats (larch forest, birch forest, meadow steppe and thermokarst lake). We explore the relationship between the biogeochemical differences among habitats and the active layer microbial community via a spatial (across habitats, and with depth through the active layer) community survey using high-throughput Illumina sequencing. Microbial communities showed significant differences between active and frozen layers and across ecosystem types, including a high relative abundance of Alphaproteobacteria, Firmicutes, Crenarchaeota, Bacteroidota and Gemmatimonadota in the active layer and a high relative abundance of Actinobacteriota and Desulfobacterota in the frozen layer. Soil pH, temperature and moisture were the most significant parameters underlying the variations in the microbial community composition. CCA suggested that the differing environmental conditions between the four soil habitats had strong influences on microbial distribution and diversity and further explained the variability of soil microbial community structures.

This is the first report on comparative characterization of the taxonomic diversity of microbial communities in the hydrotherms of the Baikal Region with various physicochemical conditions by molecular genetic methods. Comparative analysis of the composition of the dominant taxa revealed the differences depending on sampling site and sample type. The community of high-temperature areas with a water temperature of 55–73°С was shown to contain a high proportion of thermophilic bacteria Deinococcota, Acetothermia, Aquificota and, Armatimonadota; at temperatures below 35°С, the representatives of Bacteroidota were predominant. The members of the phyla Pseudomonadota and Bacillota were found within a wide temperature range of hydrotherms under study, which was indicative of their broad adaptive potential. In thermal and subthermal springs, the main factors determining the diversity of communities were mineralization, sodium, chloride and sulfate ion content, as well as temperature.