The development of new effective preparations for the correction of microecological disorders based on probiotic derivatives requires a comprehensive study of the biological activity of the latter. We studied the proliferative activity and biofilm formation by clinical isolates: Escherichia coli and Pseudomonas aeruginosa under the influence of cell-free extracts containing structural components and metabolites of the Bifidobacterium bifidum and Lactobacillus reuteri probiotic strains. Cell-free extracts were obtained from disintegrates and cultures of probiotics. Disintegrates were prepared by cyclic freezing-thawing of probiotic cell suspensions. The cultures were obtained by cultivating probiotic microorganisms in their own disintegrates. The obtained disintegrates and cultures were filtered. The proliferative activity of the test cultures was studied using the spectrophotometric microtiter plate method after an hour-long exposure in undiluted cell-free extracts and subsequent cultivation in a nutrient medium containing 30%vol of the studied extracts at 37 °C for 24 hours. The biofilm formation of the test cultures was studied with 30% vol content of cell-free extracts in the cultivation medium using the spectrophotometric microtiter plate method. All the studied extracts exerted a similar effect on the proliferative activity and biofilm formation by E. coli and P. aeruginosa. Exposure of the test cultures in all undiluted extracts during an hour led to a significant decrease in the optical density of the test samples: optical density of the test wells ranged from 36.5% to 49.8% of the control wells. The test cultures that were exposed to the extracts: filtrate of L. reuteri disintegrate (L), filtrate of В. bifidum disintegrate (B) and filtrate of В. bifidum culture, grown in В. bifidum disintegrate (MB) after dilution and subsequent cultivation over the next 24 hours completely restored the ability to proliferate. The proliferative activity of the test cultures that were exposed to the extracts: filtrate of L. reuteri culture, grown in L. reuteri disintegrate (ML) and filtrate of L. reuteri culture, grown in L. reuteri disintegrate supplemented with 0.8 M glycerol and 0.4 M glucose (MLG), was significantly inhibited after dilution and subsequent cultivation. The inhibition indices calculated for the ML extract were: 25.9% (E. coli) and 53.0% (P. aeruginosa). Inhibition indices calculated for the MLG extract were: 62.0% (E. coli) and 96.9% (P. aeruginosa). MLG extract had more pronounced inhibitory effect on the proliferation of the test cultures than ML extract. All the studied extracts exerted significant inhibitory effect on the biofilm formation of the test cultures. Analysis of the results of the study shows that cell-free extracts of L. reuteri culture grown in its disintegrate without supplementation or supplemented with glycerol and glucose have the highest antimicrobial activity and can be used as metabiotics to prevent overgrowth of potentially pathogenic bacteria, as well as inoculation and proliferation of pathogenic gram-negative bacteria in the gastrointestinal tract. They can be used alone or in combination with cellular probiotics to enhance their probiotic action. This study encourages further careful investigation of the biochemical composition of cell-free extracts and clarifying the mechanism of their action.

The influence of basic physical factors caused by magnetite nanoparticles (constant magnetic field and sorption) on microorganisms by examining the reactions of the intensity of free radical lipid peroxidation (FRLP) and bacteriostatic action was studied. It was well established that the magnetite nanoparticles caused unequal reaction in intensity of FRLP on different groups of microorganisms. It was determined that the most significant factor that influenced on the ultimate indicator of the intensity of luminescence on C. albicans, E. coli and P. aeruginosa was constant magnetic field which induced by nanoparticles. On the contrary, sorption was the most significant factor on S. aureus. It was found that the rate of consumption of free radicals lipid reduced reliably on all microorganisms after their processing by magnetite nanoparticles. The results of microbiological studies of E. coli, K. pneumoniae and S. aureus showed that bacteriostatic effect was detected after exposure by magnetite nanoparticles. Visually, it was detected by decreasing the number of colonies on the nutritious medium in comparison with the control. It was revealed an interesting fact that saline NaCl, which had previously been processed by magnetite nanoparticles also significantly had a marked bacteriostatic effect on the studied microorganisms. This effect could be explained by mechanism of change the polarization structure water of microorganisms by magnetite nanoparticles. It was discovered that degree of expression of bacteriostatic action which induced by magnetite nanoparticles had correlation with marks of reactions intensity of FRLP. Maximum bacteriostatic effect on S. aureus was expressed in second variant application of magnetite nanoparticles where mechanism of sorption was more significant than action of the magnetic field. On the contrary, maximum bacteriostatic effect on E. coli and K. pneumoniae was revealed in third variant, where time exposition of contact with microorganisms nanoparticles and, consequently, action of a constant magnetic field was determinative.

Recent studies have shown that alterations of the immune response in the gastrointestinal mucosa are key components of the mechanism of the probiotic action of beneficial bacteria. Most of the beneficial effects of probiotics are due to the action of their structural components and metabolites. Macrophages are first-line defense cells of the immune system, which not only participate in the detection, phagocytosis and destruction of harmful microorganisms, but also determine the nature of the subsequent immune response by presenting antigens to T-cells and initiating inflammation by releasing cytokines. We researched the effect of two types of cell-free extracts (CFEs) containing probiotic derivatives (structural components and metabolites of bacteria) Bifidobacterium bifidum 1 (BbCFE) and Lactobacillus reuteri DSM 17938 (LrCFE) on the activity of mouse peritoneal macrophages and on the ability of peripheral human blood mononuclear cells to produce cytokines. CFEs were obtained by culturing probiotics in their own disintegrates and then removing cells and cell debris by centrifugation and filtration. Peritoneal macrophages were isolated from mice. Some of them were infected in vitro by Salmonella thyphimurium. Uninfected and infected macrophages were incubated in culture medium containing (30% vol) or not containing CFEs at 37 °С in a microaerobic atmosphere (5% СО2) for 18 hours. After incubation, peritoneal macrophages were lysed. The obtained suspensions were centrifuged and supernatants were carefully collected. Macrophages activity was assessed by the nitrites level, superoxide dismutase (SOD), lactate dehydrogenase (LDH) activity and antiinflammatory cytokines levels in supernatants using spectrophotometric method. Peripheral mononuclear cells were isolated from the blood of healthy volunteers. The ability of peripheral mononuclear blood cells to produce antiinflammatory cytokines was evaluated after cell stimulation with lipopolysaccharide (LPS) and incubation with or without CFEs. Cytokine levels in supernatants were determined using enzyme-linked immunosorbent assay (ELISA). After infection with S. thyphimurium in macrophages, nitrite levels increased 5.5-fold, SOD activity 4.8-fold, and LDH 2-fold. Both studied CFEs exerted a similar effect on the macrophages’ activity. Addition of BbCFE to the incubation medium of infected macrophages resulted in a 4-fold decrease in nitrite levels, and the addition of LrCFE was accompanied by a decrease in nitrite levels to levels in intact cells. Under the influence of both CFEs, the activity of SOD and LDH was significantly reduced and did not differ significantly from the activity of these enzymes in intact cells. BbCFE and LrCFE did not have a significant effect on nitrite levels, SOD and LDH activity in intact macrophages. Under the influence of BbCFE, there was a 2-fold decrease in the production of TNF, a 2-fold increase in IL10 production, and a 30% increase in IL6 production by mononuclear cells. LrCFE caused a decrease in TNF production by 26.7% and IL6 by 36%, and IL10 by 1.9 times. Thus, the studied CFEs normalized the nitrite levels in peritoneal macrophages infected with S. thyphymurium and infection-induced activation of SOD and LDH enzymes. This demonstrates their ability to modulate oxidative processes in macrophages. In addition, under the influence of the investigated CFEs, there was a decrease in the production of pro-inflammatory cytokines (TNFα and IL-6) and increased production of anti-inflammatory cytokine (IL-10) by human peripheral mononuclear cells. The results of the study indicate the ability of CFEs by influencing the functions of innate immunity cells to restrict the inflammatory response and oxidative stress. Based on this, CFEs can be considered as promising agents for the treatment of inflammatory diseases.

The aim: analysis of literature data concerning the study on the relationship between changes in the composition, metabolic activity of the intestinal microbiota and the development of neuropsychiatric disorders and diseases. Results. Despite the different etiopathogenesis and clinical manifestations, neuropsychiatric disorders and diseases share common pathogenetic links: intestinal dysbiosis with depletion of microbial diversity, an increase in the representation of “pro-inflammatory” taxa and changes in the metabolism of the intestinal microbiota; damage of the mucosal barrier and increased permeability of the intestinal wall; immune response activation with the development of systemic inflammation and neuroinflammation; impairment of the nervous, endocrine and metabolic mechanisms of signal transmission within the gut-brain axis. Specific changes in the composition and metabolic activity of the intestinal microbiota act as biomarkers or additional diagnostic criteria at some neuropsychiatric diseases. Therapeutic approaches aimed at correcting the composition and metabolic activity of the intestinal microbiota: fecal transplantation, the use of psychobiotics and neuroactive derivatives of probiotic bacteria demonstrate a positive effect. Conclusions. The mechanisms of the specific microorganisms and their derivatives for influencing the functional activity of the central nervous system require further study. The gut microbiome should be considered as a target organ in the diagnosis and treatment of neuropsychiatric disorders and diseases. The microbiome-based approach contributes to early diagnosis and prediction of the clinical course severity. Targeting the correction of the intestinal microbiota composition and functional activity is a promising strategy for increasing the effectiveness of the neuropsychiatric pathology treatment.

The influence of basic physical factors caused by magnetite nanoparticles (constant magnetic field and sorption) on microorganisms by examining the reactions of the intensity of free radical lipid peroxidation (FRLP) and bacteriostatic action was studied. It was well established that the magnetite nanoparticles caused unequal reaction in intensity of FRLP on different groups of microorganisms. It was determined that the most significant factor that influenced on the ultimate indicator of the intensity of luminescence on Candida albicans, Escherichia coli and Pseudomonas aeruginosa was constant magnetic field which induced by nanoparticles. On the contrary, sorption was the most significant factor on staphylococcus aureus. It was found that the rate of consumption of free radicals lipid reduced reliably on all microorganisms after their processing by magnetite nanoparticles. The results of microbiological studies of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus showed that bacteriostatic effect was detected after exposure by magnetite nanoparticles. Visually, it was detected by decreasing the number of colonies on the nutritious medium in comparison with the control. It was revealed an interesting fact that physiological salt solution (saline NaCl), which had previously been processed by magnetite nanoparticles also significantly had a marked bacteriostatic effect on the studied microorganisms. This effect could be explained by mechanism of change the polarization structure water of microorganisms by magnetite nanoparticles. It was discovered that degree of expression of bacteriostatic action which induced by magnetite nanoparticles had correlation with marks of reactions intensity of FRLP. Maximum bacteriostatic effect on staphylococcus aureus was expressed in second variant application of magnetite nanoparticles where mechanism of sorption was more significant than action of the magnetic field. On the contrary, maximum bacteriostatic effect on Escherichia coli and Klebsiella pneumoniae was revealed in third variant, where time exposition of contact with microorganisms nanoparticles and, consequently, action of a constant magnetic field was determinative.