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A short-term chronosequence of paleosols buried under different structures in the big Essentuksky 1 kurgan (North Caucasus) was studied. The kurgan was constructed in the second quarter of the 4th millennium BC (the Maikop culture). According to archaeological data, the kurgan construction continued for several decades. During this time, the morphological pattern and physicochemical properties of soils changed: the thickness of the humus profile and the content of organic carbon decreased, the contents of gypsum and carbonates increased, the zone of their accumulation shifted upwards the soil profile, and the transformation of carbonate pedofeatures took place. The most “arid” properties were found in the soil buried last in the studied chronosequence: the humus horizon of this soil is the lightest in color and has the lowest organic carbon content; the soil profile is most enriched in carbonates, which is manifested both at the macro- and microlevels of observation; the highest content of exchangeable sodium and magnesium is noted in the composition of exchangeable bases; a decrease in the magnetic susceptibility and a maximum in the gypsum content are observed in the second meter of the soil profile. During the construction of the kurgan, Calcic Chernozems (Loamic, Pachic) evolved into Haplic Calcisols (Loamic). A palynological analysis revealed a decrease in the area of forest vegetation and an increase in the share of herbaceous vegetation in the spectrum, including the appearance of steppe species and xerophytes in the region over the studied time. The climate of the studied time interval (the early stage of the Maikop culture in the North Caucasus) was arid and warmer than that at present.

Whole-genome sequencing of bacteria Bacillus velezensis BIM B-439D has revealed that its genome is represented by a single circular chromosome 3 978 954 bp in size and contains 3969 predicted genes. Chromosome has 10 conserved loci that determine the production of antimicrobial compounds of varying chemical nature, namely lipopeptides (surfactin, bacillomycin, fengycin), polyketides (bacillaene, difficidin/oxydifficidin, macrolactin), bacillibactin siderophore, dipeptide bacilysin, a protein/polyketide of uncertain composition, and amylocyclicin bacteriocin. Mutants with impaired surfactin synthesis have been obtained by direct mutagenesis; they were characterized by an increased production of bacillomycin and fengycin. The obtained mutants demonstrated high antimicrobial activity towards a number of bacterial and fungal pathogens (Penicillium expansum, Alternaria tenuis, Botrytis cinerea,Bipolaris sorokiniana), but they inhibited the growth of the Fusarium genus fungi to a lesser degree.

The published data and our own data on the mechanisms of the influence of microbial probiotics, prebiotics, and their combinations on the processes of symbiotic digestion have been considered and generalized. It is shown that the effects on an organism are associated with the enhanced metabolic activity of intestinal bacteria: stimulation of bacterial fermentation of carbohydrates and formation of short-chained fatty acids, an increase in the blotting capacity of the intestines due to elongation of villi and deepening of crypts, and a decrease in secretion of toxic proteolytic products (ammonia, phenols, thiols, indoles, etc.). It has been shown that a combination of probiotics and prebiotic enhances the biological efficiency of a complex preparation, which contributes to activation of carbohydrate, protein, and mineral metabolism.