[Applyed aspects of molecular biology of Bifidobacteria and Lactobacillus].

The data obtained in the molecular genetic studies of the representatives of the genera Bifidobacterium and Lactobacillus are given. At present the genomes of Bifidobacterium longum, Lactobacillus acidophilus and Lactobacillus plantarum sized 2,256.640, 1,993.564 and 3,308.274 base pairs respectively, were completely sequenced. The use of different methods of gene indication and gene typing essentially widened the existing notions of the species variety of these bacteria, made it possible to change the classification of known species and to find out new ones, vegetating in different biotopes of the human body. Molecular genetic approaches also ascertained the taxonomic position of production strains of lactic-acid bacteria used in food industry, helped determine the kinetics of the passage of probiotic strains of bifidobacteria and lactobacilli along the gastrointestinal tract, as well as determine the duration of their preservation in the intestine after oral administration. In addition, the data on the evaluation of the therapeutic effect of some preparations, probiotics and synbiotics, with determination of the population level of endogenic and orally introduced exogenic bifidobacteria and lactobacilli are presented.