The consortium of symbiotic strains of lactobacilli Lactobacillus plantarum MDIIE 2165 and Lactobacillus rhamnosus MDIIE 2166, deposited in the All-Russian Collection of Microorganisms (IBFM RAS), is the most suitable starter for obtaining a fermented beet juice (FBJ). These innovative probiotic lactobacilli ensure a deep processing of raw materials and allow a specialized food product with high organoleptic characteristics, biological value and adaptogenic properties to be obtained. FBJ can be used as a specialized nutrition product to improve the performance of athletes and people working and living in extreme conditions, as well as to prolong the professional longevity of the population.

The use of a biomodel of the confluent monolayer Caco-2 of enterocytes allowed us to reveal the ability of the S-protein isolated from strain LC2029 to prevent permeability disorders resulting from intestinal infections induced by pathogens (E. coli O157: H7, C. jejuni ATCC 33291, S. enteritidis ATCC 25928). This is important for maintaining the efficiency of the intestinal barrier.

In order to solve the demographic problem that has arisen in Russia, comprehensive multilateral approaches are required, aimed at increasing the birth rate and reducing child and adult mortality. One approach to solve this problem is directed regulation of the human microbiome.

Bacteriocins are bacterial proteins or peptides exhibiting antimicrobial activity and synthesized on ribosomes. For a high molecular weight bacteriocin produced by the Limosilactobacillus fermentum IIE MD-150 strain and having the GRAS status (Generally Recognized as Safe), an amino acid sequence homology with enterolysin A produced by the Enterococus faecalis LMG 2333 strain was found. Lactobacillus fermentum IIE MD-150 can be used in the prevention and complex treatment of infectious diseases caused by antibiotic-resistant strains of Staphylococcus aureus.

This paper shows that in the solid-state cultivation of Lactobacillus plantarum 8R-A3 on wheat bran, a biofilm was formed on the surface of the carrier within 48 h. Prolongation of fermentation caused a drop in the number of CFU from 96% of the initial total number of cells to 8.8% by 72 h. When the temperature was raised from 37 to 45°C, which led to drying of the fermentation mass, the CFU index decreased to <104. According to fluorescence microscopy data, up to 40% of bacteria with signs of life survived in the dry specimens. After keeping the mice on a diet with the introduction of 0.05% of fermented bran dried for 72 hours, a strain genetically identical to the L. plantarum 8R-A3 was extracted from the colon. In animals with amikacin-inhibited intestinal lactobacilli, their normal level recovered. It is suggested that L. plantarum 8R-A3 generates uncultivable forms, which are reanimated by passage through the animal organism and exhibit probiotic activity. The biofilm formed in the solid-state cultivation contributes to the survival of lactobacilli cells in drying of the fermentation mass.

Structural and functional properties of recombinant IL-4delta2, a naturally occurring splice variant of human IL-4 with a deletion of the loop region 22-37, have been analyzed. IL-4delta2 has alpha-helical structure and most likely preserves the "up-up-down-down" topology typical of the four-helix-bundle cytokines. IL-4delta2 interacts specifically with the alpha chain of IL-4R and competes effectively with IL-4 for the common binding sites. Thus, IL-4delta2 may act as a regulator of the cytokine net, being the natural antagonist of IL-4.

Yersinia pestis capsular antigen Caf1 is shown to be a beta-structural protein that in polymeric form possesses very high conformational stability. Different approaches show that a dimer is the minimal cooperative block of Caf1 adhesin. Caf1 dimer interacts effectively with IL-1 receptors of human macrophage and epithelial cells. The specificity of such interaction is confirmed by the inhibition of IL-1alpha binding by Caf1. The Caf1 role in pneumonic plague pathogenesis is discussed.

A comparative study of the structural and functional properties of recombinant Yersinia pestis Caf1 and human IL-1beta was performed. According to Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) data, IL-1beta and Caf1 are typical beta-structural proteins. Neither protein interacts with the hydrophobic probe ANS (8-anilino-1-naphthalenesulfonate) under physiological conditions. Specific binding of Caf1 [K(d) = (5.4 +/- 0.1) x 10(-10) M] to interleukin-1 receptors (IL-1Rs) on the surface of finite mouse fibroblasts (line NIH 3T3) was observed. Caf1 is able to inhibit high-affinity binding of (125)I-labeled IL-1beta to NIH 3T3 cells, and in the presence of Caf1, the binding of [(125)I]IL-1beta is characterized by a K(d) of (2.0 +/- 0.3) x 10(-9) M. Caf1 binding to IL-1R could reflect adhesive properties of the capsular subunits responsible for the contact of bacteria with the host immunocompetent cells. In its turn, this may represent a signal for the initiation of the expression and secretion of the proteins of Y. pestis Yop virulon. Thus, these results help to explain the importance of Caf1 in the interaction of Y. pestis with the host immune system.

The priming effect of insulin on the fMLP-induced respiratory burst of mouse neutrophils as well as the involvement of tyrosine protein kinases and phosphatases in this process have been studied. Peritoneal evoked neutrophils of NMRI strain mice were incubated with 0.01-100 nM insulin for 1-60 min at 22, 30, or 37°C and activated by 0.1-50 μM N-formyl-methionyl-leucyl-phenylalanine (fMLP). The production of reactive oxygen species (ROS) by neutrophils was monitored by luminol-dependent chemiluminescence. We found that 125I-labeled insulin binding by mouse neutrophils occurred with saturation and high affinity. Insulin itself did not change the basal level of the ROS production but could modulate fMLP-induced respiratory burst. The effect of insulin depended on temperature and duration of pretreatment of the neutrophils with insulin and the concentration combination of the insulin and fMLP. The tyrosine kinase inhibitor tyrphostin 51 decreased the fMLP-induced respiratory burst significantly. Insulin did not change the fMLP response of neutrophils pretreated with tyrphostin. However, the effect of tyrphostin on the response to 50 μM fMLP was considerably decreased in neutrophils treated with insulin. There was no such effect during activation by 5 μM fMLP, for which the priming effect of insulin was not observed. Insulin did not increase the fMLP-induced respiratory burst in neutrophils treated with the protein phosphatase inhibitors orthovanadate and pyrophosphate. If the inhibitors were added after insulin, the combined effect was nearly additive. It is possible that priming by insulin of the fMLP-induced respiratory burst is triggered by tyrosine phosphorylation, realized with its participation, and involves the signaling pathways initiated by tyrosine phosphorylation but subsequently is not dependent on the latter. The role of protein phosphatases in priming by insulin is of little importance. The data indirectly confirm the idea that priming of the neutrophil respiratory burst is a result of crosstalk of signaling pathways of the insulin and fMLP receptors with the participation of tyrosine phosphorylation.

The role of conformational changes in the mechanism of cryoprecipitation of human monoclonal immunoglobulin M (IgM) was studied. It was demonstrated that the variable moiety of the Fab-region of cryo-IgM has a site which comprises 5 to 6 charged amino acid residues. This site is responsible for intermolecular electrostatic interactions which lead to the formation of a precipitate with a decrease in temperature. This interaction is cooperative and stabilized by dipole molecules of H2O. The chain growth during aggregation is nuclear. The primary nucleus contains three IgM macromolecules. stability of the three-molecule nucleus is provided for by 16--17 intermolecular links. Using circular dichroism and fluorescent methods, it was found that the formation of a cryoprecipitate is accompanied by ionic pair release and conformational changes.

A chemical modification of carboxylic groups of monoclonal human cryoglobulin M has been studied. The modification by a chromophoric carbodiimide was accompanied by complete loss of IgM cryoprecipitating properties. The number of carboxylic groups important for biological activity was estimated by the Tsou method and found to be 2. The cryoprecipitation dependence on ionic strength has been investigated and the number of ions per binding site isolated upon formation of intermolecular ion couples has been estimated. Mechanism of cryoprecipitation stipulated by intermolecular cooperative electrostatic interactions is proposed.

The effect of the chemical modification of lysine, histidine, arginine, tyrosine, tryptophan residues and carboxylic groups on the cryoproperties of monoclonal human cryoglobulin M has been studied. The modification of 35–40 lysine residues and that of 42–45 arginine residues in the molecule of cryo-IgM has been shown to result in practically complete inhibition of the cryoprecipitation. The same effect is observed on the modification of 60 histidine residues per molecule and on modification of 50or 51 carboxylic groups. At the same time the modification of practically all the reagent-exposed tryptophan (10 residues per molecule) and tyrosine residues (55 residues per molecule) does not lead to any noticeable decrease in the cryoprecipitation. The conformation of the modified and native proteins are identical according to the circular dichroism data.