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Antibiotic salvin obtained from Salvia officinalis has been studied for its effect on the growth and ultrastructure of Staphylococcus aureus 209P. The antibiotic in the sub-bacteriostatic concentration considerably elongates the lag-phase (up to 11-12 h) exerting no significant effect on the growth rate of the staphylococcus population as well as it prolongs duration of the exponential phase. The analysis of electronograms of staphylococcus cells subjected to the action of salvin in the concentrations similar to the minimal inhibitory concentration (MIC), has revealed the cell thinning, inhibition and destruction of the division. The introduction of 5MIC antibiotic into the exponentially grown culture made a cell wall considerably thinner, destructing its external layer; the number of lyzed cells sharply increased. The appearance of bodies not described previously with a membrane envelope and ribosomes as well as of mesosomal structures was observed.

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Bacteria capable of hexavalent chromium (Cr6+) reduction can be found in Cr6+-containing sewage and sediments of purification tanks of industrial plants. They cannot be detected in water and soil samples containing no chromium compounds. Bacteria reducing chromium belong to the genera Aeromonas, Escherichia, Pseudomonas and Enterobacter. Their activity of Cr6+ reduction correlates with the high resistance to the elevated content of this ion in the medium. The fine cell structure of these bacteria is described.

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The effect of antibiotic Al-87 on the ultrastructure of staphylococcal cells was studied. The cells of a control culture of a sensitive strain of S. aureus, 209P at the early exponential growth phase were characterized by thin walls (20-22 nm) and septa (30 nm). In the presence of the subbacteriostatic concentration of antibiotic AL-87 (0.02 microgram/ml) the thickness of the cell walls and septa increased up to 80-90 and 150 nm, respectively. Segregation of the septa was retarded and 4 cell conglomerates formed. The cell division appeared to be highly active: the septa were detected in 80-90 per cent of the sections against 40 per cent in the control. Therefore, antibiotic AL-87 induced significant thickening of the cell walls and impairment of the cell division regulation. Investigation of the staphylococcal variant resistant to the antibiotic showed that there were no significant differences between the cells grown in the absence and presence of antibiotic AL-87 (in a concentration of 200 micrograms/ml). In both the experiments there were detected cells in their majority with thinner walls, L-form-like structures, protoplasts and single conglomerates of the cells with thicker walls and anomalous division and the cells at the moment of lysis. It suggested that the effect of antibiotic AL-87 on the cell wall structure was not direct i. e. by inhibition of protein synthesis but mediated i. e. due to shifts in lipid synthesis inducing changes in lipid-dependent synthesis of the cell wall polymers.

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On studying the ultrathin sections of the Candida yeast cells, continuously and periodically cultured in the mineral medium with n-alkanes it has been shown that microbodies (peroxisomes) may be present both in the nucleus and in the perinuclear zone form which they are able to migrate into the cytoplasm. The endoplasmatic reticulum, the Golgi apparatus and mitochondria are not presumably involved structurally in the appearance of microbodies. The data were presented on close structural and functional resemblance between microbodies and mitochondria. It is supposed that in n-alkane-assimilating cells Candida microbodies may be precursors of mitochondria.

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A large number of bacterial strains assimilating chemical ethanol has been isolated using an original technique. Active growth of strains belonging to the genera Pseudomonas and, particularly, Acinetobacter was registered on mineral media containing ethanol. A mathematical model was constructed select a strain of Acinetobacter calcoaceticus K-9 during its continuous cultivation on media containing ethanol. The model makes it possible to determine conditions for producing a present amount of the biomass, the percentage of its yield, and the produc;iveness as a function of the dilution rate, temperature, and the concentration of ethanol and phosphoric acid in the medium. The main characteristics of the growth process in the studied factor space were established. The optimum conditions were calculated for growth of the strain with respect to each of the criteria. Under various conditions of bacterial growth, changes in the morphology and ultra-fine structure of the cells correlated with their physiological activity. The volume of the cells increased with the rate of dilution of the medium: the process can be described by a saturation curve. The presence of mesosomal structures is typical of the cells growing at low flow rates.

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In the C. tropicalis K-41 cells fixed by glutaraldehyde and osmium most membranes consisted of two electron-transparent and one electron-dense layer. Morphologo-structural peculiarities of the cell fraction grown at 39 degrees testify to a certain disconnection of energetic and constructive metabolism, inhibition of synthetic processes. Cell division was more active at 29 degrees.

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