Whole-genome DNA sequencing of Lactobacillus D75 and D76 strains (Vitaflor, Russia) was determined using the PacBio RS II platform, which was followed by de novo assembly with SMRT Portal 2.3.0. The average nucleotide identity (ANI) test showed that both strains belong to the Lactobacillus helveticus, but not to the L. acidophilus, as previously assumed. In addition, 31 exopolysaccharide (EPS) production genes (nine of which form a single genetic cluster), 13 adhesion genes, 38 milk protein and 11 milk sugar utilization genes, 13 genes for and against specific antagonistic activity, eight antibiotic resistance genes, and also three CRISPR blocks and eight Cas I-B system genes were identified in the genomes of both strains. The expression of bacteriocin helveticin J genes was confirmed. In fact, the presence of identified genes suggests that L. helveticus D75 and D76 are able to form biofilms on the outer mucin layer, inhibit the growth of pathogens and pathobionts, utilize milk substrates with the formation of digestible milk sugars and bioactive peptides, resist bacteriophages, show some genome-determined resistance to antibiotics, and stimulate the host’s immune system. Pathogenicity genes have not been identified. The study results confirm the safety and high probiotic potential of the strains.

The growth in the number of chronic non-communicable diseases in the second half of the past century and in the first two decades of the new century is largely due to the disruption of the relationship between the human body and its symbiotic microbiota, and not pathogens. The interaction of the human immune system with symbionts is not accompanied by inflammation, but is a physiological norm. This is achieved via microbiota control by the immune system through a complex balance of pro-inflammatory and suppressive responses, and only a disturbance of this balance can trigger pathophysiological mechanisms. This review discusses the establishment of homeostatic relationships during immune system development and intestinal bacterial colonization through the interaction of milk glycans, mucins, and secretory immunoglobulins. In particular, the role of fucose and fucosylated glycans in the mechanism of interactions between host epithelial and immune cells is discussed.

One of the aspects of bacterial symbiosis with the host is the exchange of metabolites. Stimulation of the growth of beneficial bacteria in the microbiota using the metabiotic Actoflor®-S led to a change in the composition of the flow of its metabolites. Analysis of the blood metabolome of mice by GC-MS showed that the animals receiving Actoflor®-S had an increased concentration of almost all amino acids and a decreased concentration of most carboxylic acids and their derivatives, including lactic acid. Comparison of the obtained results with literature data showed that the action of Actoflor®-S leads to normalization of the concentration of at least 10 marker compounds, whose concentration was significantly changed in patients with ulcerative colitis. The property to normalize the composition of the metabolome turned out to be inherent only to the entire set of Actoflor®-S components, but not to its parts, which is an indicator of the emergent properties of the metabiotic. Overall, the results of the work also indicate that all metabolites of the metabolome are important participants in maintaining health; often, they have individual activity, but in most cases, their activity is a consequence of their combined action.

The aim of the current work was to search for bioactive peptides Ile-Pro-Pro (IPP) and Val-Pro-Pro (VPP) with antihypertensive action in the culture medium (CM) of probiotic Lactobacillus helveticus D75 and D76 strains when cultured in milk. The CM composition was analyzed using HPLC-UV, HPLC-MS, and MALDI Fourier transformation ion-cyclotron resonance mass spectrometry (MALDI FT-ICR MS, Varian). Direct analysis of CM using FT-ICR failed to detect peptides in the original CM due to the high concentration of concomitant components, but after preliminary fractionation of CM by HPLC, both peptides were detected. The masses (m/z) of characteristic ions were 312.19 (VPP) and 326.21 (IPP). Peptides were quantified using a single reference method with HPLC and time-of-flight mass spectrometry. The concentrations of VPP and IPP in the CM of the D75 strain, respectively, reached 18.0 µg/mL and 25.4 µg/mL, in the CM of the D76 strain they were lower (12.7 µg/mL and 16.2 µg/mL), and in the mixed CM (both strains) the concentrations reached intermediate values of 15.7 µg/mL and 24.0 µg/mL. The data obtained indicate the existence of an active complex of extracellular enzymes in L. helveticus D75 and D76, which provide the production of IPP and VPP peptides with antihypertensive effect. The results also confirm the symbiotic properties of D75 and D76 strains (synergism and syntrophy). Functional foods based on milk fermented by probiotic L. helveticus D75 and D76 strains, which contains IPP and VPP peptides in effective doses (>3.0 mg/day), can be considered a safe and effective non-pharmacological intervention in patients with mild hypertension.