SARS-CoV accessory protein Orf8b is involved in suppressing interferon-mediated immune response of the infected cell and this might lead to supposition that the corresponding protein 2019-nCoV Orf8 shares the same role. But the tertiary structures of these proteins are still unknown, and the primary structures demonstrate very low homology and different calculating parameters. This time they both are affected by stabilizing selection and in natural viral populations do not tend to be deleted. The question whether in this case very different proteins could share the same function rises from the present data.

The functioning of well-studied key groups of soil microorganisms depends on the microbial ecosystem in which they function in interaction with species belonging to other ecological groups. An analysis of the composition of the soil microbiota, and the possibility of analyzing the number of representatives of specific species, remains an urgent task of soil microbiology. Such analysis could be performed using modern and expensive methods such as metagenomics and mass-spectrometry, but some questions could also be answered using real-time PCR. This well-known approach is rather cheap for massive analysis and is ready to present reproducible results for practical agricultural applications. Understanding the variability of the primary structure of 16S rRNA is key to the reliable identification of bacterial species and provides an opportunity to choose the optimal pathways for their detection by PCR. In this work, analysis of the sequences of 16S rRNA of two species of soil bacteria, Acinetobacter lwoffii and Paenibacillus taichungensis is carried out. The most variable and most conservative areas on the level of species are detected. It was proved that conventional variable and conservative areas of the gene have on average nearly the same level of variability on the intraspecies level.

The structure of soil microbial communities and the factors that control it are still poorly understood and cause ongoing interest. The diversity of soil bacteria reflects the diversity of existing ecological niches and trophic connections between them and with other components of the ecosystem. The presence of certain taxa with their own characteristic properties depends on the specific environmental conditions. Analysis of the composition of soil microbiota in various physicochemical conditions allows identify landmarks for understanding the principles by which it is formed. Of particular interest in this regard are the features of cultivated fertile soils that assist agricultural production. In this paper, we have assessed the occurrence of representatives of different families of bacteria in arable and nonarable chernozems of three subtypes. The methodology of 16S microbial profiling was used. The general features of the taxonomic structure of bacterial communities of chernozem remain similar, with a high occurrence of the families Sphingomonadaceae, Xanthobacteraceae, Rubrobacteraceae and Chitinophagaceae. Notably, Gemmatimonadaceae, one of the most commonly occurring families, is approximately twice as represented in arable soils as in nonarable ones. Differences between subtypes of chernozem and between arable and nonarable areas concerned different sets of bacterial families. Among others, the occurrence of representatives of families characterized by nitrogen fixation, nitrite oxidation and reduction, ethanol oxidation, biodegradation and microbial predation is touched upon. The obtained results raise the question of the factors limiting the number of certain groups of bacteria in various soil conditions and so limiting their contribution to the properties of the ecosystem.

Soil microbial communities perform a number of important functions ensuring fertility. They depend on physical and chemical composition of soil and applied agricultural technology. To control the state of the soil, it is necessary to use methods that allow to quickly assess the dynamics of the structure of microbial communities. To develop convenient method for analysis of microbiota the set of taxon-specific primers for RT PCR, recognizing 16S rRNA genes of domain Bacteria, six bacterial phyla and one class was chosen. Calculation of the percentages of lower-order taxa in the upper-order taxon was carried out based on the number of amplification cycles required to achieve the threshold value of fluorescence intensity taking into account the values of amplification factors. Taxonomic structure of the bacterial component of the soil microbial community was analyzed using as an example a sample of the surface layer of arable black soil enriched with regular application of organic fertilizers. The compiled analysis protocol made it possible to obtain data on the percentages of phyla Firmicutes, Bacteroidetes, Actinobacteria, Verrucomicrobia, and of class Gammaproteobacteria belonging to phylum Proteobacteria.

The main goal of the work was to assess variability of 16S rRNA gene sequence within the nitrifying bacterial genus Nitrosomonas to find specific sequences for its detection. To achieve it, we had to find and to assess sequences that are highly conservative on the level of the genus and to find and to assess sequences variable on the level of genus but conserved on the level of species. In the SILVA database of ribosomal RNA sequences, 231 sequences of 16S rRNAs of bacteria of the genus Nitrosomonas were collected, of which were sorted 132 sequences by length from 1400 to 1541 (full-sized gene) nucleotides. We conducted an analysis of the taxon-specificity of sequences conserved at the genus level. More than a hundred full matches were found by the BLAST program in the nr database with other genera of the same and other families. So, in Nitrosomonas 16S rRNA gene are present some highly conservative regions, but they are not genus-specific due to high coincidence with other genera. Wherein, a variable region 994-1041 is highly species-specific for the species N. eutropha. Generally, the sequence of 994-1041 region of Nitrosomonas 16S rRNA genes tends to be clustered, being very close between some species.