The influence of non-tuberculous mycobacteria on the interaction of opportunistic microorganisms with erythrocytes.

Getting into a weakened organism, non-tuberculosis mycobacteria (NTMB) contact not only with the cells of the microorganism but also with the microflora of the human body; however, these interactions are poorly understood. The purpose of this work was to study the effect of NTMB supernatants on the properties of conditionally pathogenic microorganisms in their interaction with red blood cells. We used strains of non-tuberculous mycobacteria Mycobacterium iranicum and M. rutilum, as well as strains of Staphylococcus epidermidis and Escherichia coli. Using the fluorescence in situ hybridisation (FISH) method, the processes of adhesion to the surface of erythrocytes and the intra-erythrocyte penetration of cells of S. epidermidis and E. coli under the influence of NTMB supernatants were studied. To study changes in the haemoglobin molecule under the action of the supernatants of NTMB, spectral analysis was performed. Statistical processing was performed using STATISTIKA 6.0. The results showed that the supernatants of M. iranicum and M. rutilum increased the adhesion of conditionally pathogenic bacteria with a low level of AntiHbA to the surface of erythrocytes by 3-4 times. It also increased the intra-erythrocyte penetration of cells of S. epidermidis and E. coli relative to the control values. As a result of studying the haemoglobin spectrum of erythrocytes under the influence of M. iranicum, a decrease in the optical density values of oxyhaemoglobin by a factor of 2 relative to the values in the control sample was noted. Thus, the supernatants of NTMB have a multidirectional effect on the interaction of opportunistic microorganisms with erythrocytes, increasing the adhesive activity and the penetration of cells into the erythrocytes, as well as reducing the optical density of oxyhaemoglobin.

[Catalase activity of hydrocarbon-oxidizing bacteria].

The dynamics of catalase activity of the hydrocarbon-oxidizing bacteria Cordona terrae, Rhodococcus rubropertinctus, and Rhodococcus erythropolis during petroleum product destruction has been studied. A direct relationship between decreasing catalase activity of hydrocarbon-oxidizing microorganisms and the intensity of petroleum product destruction has been established experimentally. The revealed dependence allows one to consider the catalase activity of bacteria as an indicator of the initial stage of petroleum product oxidation and may be used for choosing destructor strains to construct biopreparations suitable for natural ecosystem remediation.

[Regulation of symbiotic interactions in algobacterial associations].

AIM: To study mechanisms of survival and regulation of natural algobacterial associations. MATERIALS AND METHODS: Lysozyme, antilysozyme, catalase and antagonistic activity as well as hydrogen peroxide production were determined in algobacterial associations formed by green algae or cyanobacteria and satellite bacteria. For assessment of reactions of microbial interactions, derivates of Escherichia coli, which differ on the presence of antilysozyme and catalase signs, were used. RESULTS: Multidirectional effects of symbionts in biocenosis were revealed. Involvement of functional systems lysozyme-antilysozyme and hydrogen peroxide-catalase in regulation of associative interactions in algae-bacterial biocenosis was established. In conditions of antibacterial action of algae's hydrogen peroxide, catalase activity of associate bacteria provides survival of microorganisms in association with algae, whereas high level of catalase activity promotes domination of associate bacteria in algobacterial communities. Antagonistic activity allows the microalgae to suppress growth of undesirable microorganisms and regulate their number in algobacterial cenosis. CONCLUSION: Functional systems lysozyme-antilysozyme, hydrogen peroxide-catalase as well as antagonistic activity of symbionts form the basis for regulation of symbiotic interactions in associations of water microorganisms, which has ecological and sanitary-hygienic implications.

[Effect of bacterial satellites on Chlamydomonas reinhardtii growth in an algo-bacterial community].

The growth characteristics of an algo-bacterial community (Chlamydomonas reinhardtii and bacterial satellites) were studied, as well as the mechanism and patterns of bacterial effect on algae. Four strains of predominant bacteria were isolated and partially characterized. They were assigned to the following taxa: Rhodococcus terrea, Micrococcus roseus, and Bacillus spp. A pure culture of the alga under study was obtained by plating serial dilutions on agarized media with ampicillin. Within the algo-bacterial association, the alga had a higher growth rate (0.76 day(-1)) and yield (60 microg chlorophyll/ml culture) than in pure cultures (0.4 day(-1) and 10 microg chlorophyll/ml culture, respectively). The viability of the algal cells within the association was retained longer than in pure culture. Among the isolated bacterial satellites, strains B1 and Y1, assigned to the species Rhodococcus terrae, had the highest stimulatory effect on algal growth. The culture liquid of bacteria incubated under the conditions not permitting growth stimulated algal growth; the culture liquid of actively growing bacteria had an opposite effect.