GENETIC CHARACTERISTICS OF THE ADAPTIVE POTENTIAL OF BIFIDOBACTERIA IN THE BIOTOPE OF DISTAL HUMAN INTESTINE

Aim. Determination of distinctive parameters of the B. bifidum and B. longum genomes, which characterizes their adaptive potential applied to distal intestine biotope of the human gut. Materials and methods. 5 strains of bifidobacteria have been used: B. bifidum ICIS-310, B. bifidum ICIS-643, B. bifidum ICIS-791, B. longum ICIS-505 (clinical isolates) и B. longum MC-42. Whole Genome Sequencing (WGS) has been performed by «MiSeq» DNA sequencer and «Nextera» DNA library preparation kit (Illumiina). Annotation and the primary analysis of known homologues gene content has been performed by RAST service (NMPDR). Results. B. bifidum ICIS-310 has not revealed lactose and galactose permease genes, that present in two other sequenced B. bifidum strains, but two exo-alph-sialidase genes has remained, as well as additional gene of DNA-methyltransferases family. Clinical isolates of B. longum has demonstrated a slightly more differences between each other: B. longum ICIS-505 strain contains more than 200 genes more than B. longum MC-42 reference strain, where are 29 genes - homologoues with known function. These genes are distributed uniformly by functional groups. Conclusion. Obtained data of genome analysis of the bifidobacteria reflect their specialization in occupied biotope and mutu-alistic reliability, determining dominance role of bifidoflora in human gut microsymbiocoenosis. Genome size, stability of signal census and predictability of reactions of the bifidobacteria allow to use them as a general model suitable for studying of symbiotic relations of human and his/her microbiota as well as construction of the experimental systems of intermicrobial interactions.

bifidobacteria, WGS, signal census, evolution of microsymbionts, symbiosis