ИСТИНА

Apart from performing hormonal and neuromediator functions, biogenic amines (BAs), including catecholamines (dopamine, norepinephrine, and epinephrine) and serotonin, are involved in bidirectional host organism—microbiota interactivity. Catecholamines drastically stimulate the growth and virulence of pathogenic enterobacteria [1]. The growth of a non-pathogenic E.coli strain is accelerated by catecholamines and also by serotonin [2]. The microbiota, including E. coli and lactobacilli, produce their own BAs [2] that might influence the host organism. The goal of this work was to find out whether BAs have an effect on the growth of lactobacilli. Materials and Methods. The growth of Lactobacillus acidophila on BS medium was monitored nephelometrically ( = 252 nm) and by measuring medium acidification. Freshly prepared aqueous solutions of serotonin, dopamine, and norepinephrine hydrochloride were added to the culture upon inoculation. Results. Within the physiological concentration range (10 nM to 100 M), the tested BAs only insignificantly (maximally by ~10% of the control value) increased the growth of L. acidophila. At a supraphysiological concentration (1 mM), dopamine inhibited lactobacterial growth. Conclusions. Our findings in conjunction with literature data suggest that BAs negatively influence the microbiota composition by stimulating the growth of pathogenic rather than probiotic bacteria. BAs, and particularly catecholamines, are produced in large amounts by the host under stress and, therefore, their dysbiosis-promoting influence might aggravate the detrimental effects of stress on the host’s health. In conformity with V.P. Skulachev’s “phenoptosis” hypothesis [3], BAs-stimulated pathogenic microorganisms might be implicated in eliminating stressed individual¬s—a potential burden for the whole population¬ involved. 1. Lyte, M., The microbial organ in the gut as a driver of homeostasis and disease, Medical Hypotheses, 2010, vol. 74, pp. 634–638. 2. Oleskin, A.V., El’-Registan, G.I., and Shenderov, B.A. Role of Neuromediators in the Functioning of the Human Microbiota: “Business Talks” among Microorganisms and the Microbiota-Host Dialogue, Microbiology, 2016, vol. 85, No. 1, pp. 1–22. 3. Skulachev, V.P. Phenoptosis. Programmed organism death. Biochemistry (Moscow),1999, vol. 64, pp.1679-1688.