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Investigation of Lactobacilli properties E.V.Bulycheva, E.I.Korotkova, O.A.Voronova, A.A.Kustova National Research Tomsk Polytechnic University, Russia, 634050, Lenina st. 30 E-mail: [email protected] Key words: lactobacilli, luminescence, the luminescence spectrum, the viability of the bacterial cell, the identification of the components. Introduction Lactic acid bacteria (Lactobacilli) are the microorganisms which are the main part of the normal human intestinal micro flora. They have saccharolytic type of metabolism [1,2]. They have good antagonistic activity against pathogenic microorganisms [3]. Lactobacilli are used not only in medicine, as a means to improve of digestion, but also in food industry as a useful additive to yogurts, milk, etc. Use of lactic acid bacteria as a test object for analysis of natural water toxicity is a new approach of these microorganisms application. Elaboration of the methodology of water toxicity determination is complicated and time consuming process, so, the first stage of this research was investigation of the Lactobacilli culture and their metabolites by fluorescence analysis. Obligatory condition of lactobacilli application as a test object is their viability, so, the aim of this work was to investigate the vital activity of the Lactobacilli on the example of the medicine "Lactobacterin". For this research was applied luminescent method that is based on the study of the metabolism products luminescence spectra of the Lactodacilli. These metabolites can be the markers of the bacterial viability. Materials and methods Reagents Medicine "Lactobacterin" is a microbial mass of antagonistically active living lactobacilli strains Lactobacillus plantarum 8P-A3, or L.plantarum 38 or L.fermentum 90T-C4 or L.fermentum 39, lyophilized in the culture medium with the addition of protective sucrose or gelatin sucrose-gelatinlactose medium. Equipment All investigations were done on a spectrofluorometer "Fluorat-02 Panorama", produced by "Lumex" St. - Petersburg. This device allows you to perform various investigations in a wide range of wavelengths. As a certified analyzer spectrofluorometer "Panorama" is used for the analytical control of the environment, health monitoring and process control. Methods According to instruction of the medicine "Lactobacterin" suspension was prepared by dissolving the contents of the vial in water, 5 ml of water per 1 dose of medicine. One vial contains 5 doses. For dissolving was taken 25 ml of water at room temperature. After dissolution of the medicine we had homogeneous suspension wits light yellow colour. The luminescence spectrum was obtained by synchronous scan with shift of the registration wavelength from excitation wavelength of 20 nm. Results and discussion Luminescence spectrum is a graphic dependence between signal intensity of the sample and wavelength [4]. Figure 1 shows luminescence spectrum of the medicine "Lactobacterin" Figure 1. Luminescence spectrum of the medicine "Lactobacterin" It is known that the peak on the wavelength 340 nm is NADH (reduced nicotinamide adenine dinucleotide). This substance is a participant of the Lactobacilli metabolism. Its presence shows that the bacteria is alive, so for the next study was selected wavelength 340 nm. To investigate changes of signal intensity depending on the additives were prepared some water samples with addition of different amounts of the Lactobacilli suspension. Figure 2 shows calibration dependence between signal intensity and content of the bacteria in the sample. Signal intensity, r.u 2 1,8 y = 1,6827x + 0,0423 1,6 R2 = 0,9949 1,4 1,2 1 0,8 0,6 0,4 0,2 0 0 0,2 0,4 0,6 0,8 1 1,2 Quantity of Lactobacilli, ml Figure 2. Calibration dependence between signal intensity and content of the bacteria in the sample. For the Lactobacilli viability investigation determination of the signals nature in the wavelength from 380 nm to 440 nm, luminescence spectra were obtained immediately after preparation of the suspension, and after 2 hours (Fig. 3). Luminescence spectrum is different, than previous. It is probably due to the fact that for the analysis was taken medicine from another manufacturer, but with the same content. Peaks in the spectrum differ only in intensity and doesn’t differ in the position. We can use this medicine for the next study. Figure.3. Luminescence spectra of the medicine immediately after suspension preparation (1), and after 2 hours (2) It can be concluded that the signal at the wavelengths from 380 nm to 440 nm are from components of culture medium. Luminescence spectrum of the medicine was obtained. It can be divided into three signals areas: 280 – 300 nm - nucleic acid, 340 nm – NADH, 360 – 440 nm – components of culture medium. Vital activity of Lactobacilli was investigated. The changing of the peak height at 340 nm, that matches NADH, with time, can be a marker of the bacterial cell metabolism and therefore on its vital activity. In this report it is shown, that after 2 hours bacterial cells are alive, and can be used as a test object. This study was supported by state task “Science” № 1.1310.2014 Literature references 1. U.O.Shulpekova, Lactic acid bacteria: their role in the regulation of gut motility, J.RJGGI. 3 (2010) 1-3. 2. G.G.Onischenko, V.A.Alyoshkin, S.S.Afanasev, V.V.Pospelova mmunobiological preparations and perspectives of their application in infectology, Moscow, 2002. 3. N.A.Glushanova, Biological properties of Lactobacilli, J. Bulletin of Siberian Medicine. 4 (2003) 2-3. 4. M.A.Konstantinova-Shlezinger, Luminescence analysis, Moscow, 1961.