Sporulation of Bacillus subtilis in Binary Cultures with Ultramicrobacteria.

The effect of ultramicrobacterial epibionts of the genera Kaistia (strain NF1), Chryseobacterium (strain NF4), and Stenotrophomonas (strain FM3) on the process of sporulation of Bacillus subtilis ATCC 6633 was studied. The investigated strains of ultramicrobacteria (UMB) were found to inhibit the sporulation process of B. subtilis ATCC 6633 in binary mixed cultures, exhibiting a 3-day delay of the onset of sporulation compared to the control one, an extended period of the prospore maturation, formation of the fraction of immature spores, and development of ultrastructural defects in many endospores. Thus, investigation of binary mixed cultures of B. subtilis and UMB revealed that, apart from suppression of reproduction and lysis of host vegetative cells, inhibition of spore formation and destruction of endospores was yet another feature of intermicrobial parasitism. The UMB parasites of the studied genera are assumed to participate in the regulation of development and reproduction of B. subtilis in natural habitats of this spore-forming bacterium.

[Effect of cold plasma on the E. coli cell wall and plasma membrane].

The effect of cold plasma on E. coli cells was studied. It was shown that the treatment of E. coli cells with cold plasma caused partial or total disruption of the plasma membrane integrity, which was accompanied by a release ofintracellular substances into the extracellular environment. A quantitative assessment of the extent of the damage to the cell membrane showed that a loss of no more than 23.6% of intracellular substances (calculated by the proportion of the intracellular nucleotide release) is sufficient to lead to cell death. The use of media with different ionic strength levels to create osmotic shock showed that the treatment of E. coli cells with cold plasma significantly decreased the cell wall strength.

[Corrosive activity of natural microbial associations at various conditions of cultivation].

Influence of microbial associations isolated from different ecological niches on corrosion of mild steel was changed depending on composition of medium and aeration regime. Both decrease and increase in corrosion losses were observed, which indicated that the subdivision of microorganisms into destructors and passivators of corrosion is merely conventional.

[Electron microscopic detection and in situ characterization of bacterial nanoforms in extreme biotopes].

The morphology, ultrastructure, and quantity of bacterial nanoforms were studied in extreme biotopes: East Siberia permafrost soil (1-3 Ma old), petroleum-containing slimes (35 years old), and biofilms from subsurface oil pipelines. The morphology and ultrastructure of microbial cells in natural biotopes in situ were investigated by high-resolution transmission electron microscopy and various methods of sample preparation: ultrathin sectioning, cell replicas, and cryofractography. It was shown that the biotopes under study contained high numbers of bacterial nanoforms (29-43% of the total number of microorganisms) that could be assigned to ultramicrobacteria due to their size (diameter of < or =0.3 microm and volume of < or =0.014 microm3) and structural characteristics (the presence of the outer and cytoplasmic membranes, nucleoid, and cell wall, as well as their division patterns). Seven different morphostructural types of nanoforms of vegetative cells, as well as nanospores and cyst-like cells were described, potentially representing new species of ultramicrobacteria. In petroleum-containing slimes, a peculiar type of nanocells was discovered, gram-negative cells mostly 0.18-0.20 x 0.20-0.30 microm in size, forming spherical aggregates (microcolonies) of dividing cells in situ. The data obtained promoted the isolation of pure cultures of ultramicrobacteria from petroleum-containing slimes; they resembled the ultramicrobacterium observed in situ in their morphology and ultrastructure.

[Corrosion of pipe steel samples and conjugated conversion of sulfur compounds by thiobacteria Halothiobacillus neapolitanus DSM 15147].

The kinetics of conversion of sulfur compounds by Halothiobacillus neapolitanus DSM 15147 bacteria was studied in the presence of steel samples. It was shown that the presence of steel altered the known pathway of sulfur compound oxidation by thiobacteria. Production of atomic hydrogen via the interaction between biogenic sulfuric acid and steel enhanced secondary production of intermediates and decreased the content of sulfate produced previously. The process was accompanied by pH elevation and continuation of intense growth of the thiobacterium culture. Thiobacteria formed a corrosive medium, which caused metal destruction. The protective properties of anticorrosive coatings 225 LS and 640 mk were tested. It was shown that these coatings protected steel from the destructive effect of biogenic sulfuric acid.

[Rapid assay for the assessment of a potential of chemical biocides to microbial destructors of industrial materials]. / Ekspress-metod opredeleniia aktivnosti khimicheskikh biotsidov po otnosheniiu k mikroorganizmam-destruktoram promyshlennykh materialov.

A colorimetric rapid assay for estimating the biocide potential of various chemicals towards metal biocorrosive and petroleum product degrading microbes was developed based on the reducing potential of live microbial cell. A water-soluble organic redox indicator, blue in the oxidized form and pink in the reduced form, was used as an indicator of the reducing potential of microbial cells. Once added to a suspension of vital microbial cells, it was reduced and changed in color. A good correlation between the results of this assay and viability control was obtained by employing surfactants and heavy metal ions.

[Microbiological degradation of asymmetrical dimethylhydrazine--a toxic component of rocket fuel]. / Mikdrobiologicheskaia degradatsiia nesimmetrichnogo dimetilgidrazina--toksichnogo komponenta raketnogo topliva.

A possibility of microbiological cleaning of water and soil polluted with asymmetric dimethylhydrazine (ADMH), a highly toxic rocket fuel ingredient (RFI), was studied. Several isolates (bacteria, yeast, and micromycetes) capable of utilizing ADMH as the only source of nitrogen, carbon, and energy were isolated from RFI-polluted tundra soil. Acceleration of RFI biodegradation was achieved using a biosorbent that involved cells of the degrader strain immobilized on granulated activated carbon. Biological testing in Escherichia coli and cereals (wheat and barley) demonstrated that biodegradation significantly decreased the integral toxicity of solutions containing ADMH, suggesting its utility for microbiological cleaning of polluted territories.

[Initial stages of steel biocorrosion]. / Issledovanie nachal'nykh étapov biokorrozii stali.

Initial stages of corrosion of mild steel induced by Klebsiela rhinoscleromatis BO2 were studied in various media. The effect of the microorganism was detected 8-10 h after inoculation. The number of viable cells were virtually unchanged within one month in all media, but the corrosive activity of the strain decreased. The corrosive activity of microorganisms can be determined by spectrophotometry even only after incubation for 24 h. At a low level of organic substrate, even strong colonization with microorganisms does not inevitably result in a significant damage to metals.

[Effect of space flight conditions on properties of hydrocarbon-oxidizing bacteria]. / Vliianie uslovii kosmicheskogo poleta na svoistva uglevodorodokisliaiushchikh bakterii.

Results of experiments on the Mir space station (EO-25 and EO-26) demonstrated that the conditions of orbital flight, primarily the cosmic radiation, was a mutagenic factor affecting both the genotype and phenotype of an oil-oxidizing bacterial strain, Mycobacterium flavescens EX-91. The emerging mutants differed from original culture by the rate of colony growth and the ability to ferment certain carbohydrates or synthesize beta-galactosidase. Changes in the rate of utilization of raw oil and individual hydrocarbon types (constituting model mixtures) suggest that cosmic radiation may serve as a means of obtaining mutant clones of microorganisms with new properties.

[Study of the integral toxicity of aqueous media, polluted by petroleum and petroleum products using bacterial tests]. / Issledovanie integral'noi toksichnosti vodnoi sredy, zagriaznennoi neft'iu i nefteproduktami, s ispol'zovaniem bakterial'nykh testov.

A biotest kit was used to assess the integral toxicity level of aquatic medium contamination with petroleum and petroleum-based products. The integral toxicity dynamics was also monitored during biodegradation of petroleum and petroleum-based products by an association of petroleum-degrading strains including Acinetobacter sp., Mycobacterium flavescens, and Rhodococcus sp. The following bacterial tests were used: the bioluminescence (BL) test based on Photobacterium leiognathi; electro-orientation (EO), optoosmotic (OO), and growth test; as well as the reducing activity (RA) test based on the Agrobacterium radiobacter culture. No significant increase in the integral toxicity level of aquatic medium was observed when diesel fuel and kerosene contamination had been subjected to biodegradation. Although express biotests (EO, OO, RA, and BL) detected a pronounced increase in the integral toxicity of aquatic medium, long-term growth biotest revealed no statistically significant increase in the toxicity level.

[Plant biotests of soil and water, polluted with petroleum and petroleum products]. / Biotestirovanie pochvy i vody, zagriaznennykh neft'iu i nefteproduktami, s pomoshch'iu rastenii.

Reactiona of higher plants (mustard, oat, rye, salad, dill and barley) and microalgae (Euglena gracilis) on the contamination of soil and water with petroleum and oil products was studied. The germination of seeds was analyzed. The length of sprouts, dry biomass and length of plant roots, as well as the optical density of micro-algal broth culture were determined. Negative effects of soil and water contamination with petroleum and oil products on plant and microalgal parameters examined was shown. After biological destruction of contaminants by an association of destructor strains (Acinetobacter sp., Mycobacterium flavescens and Rhodoccocus sp.), the toxicity of contaminated mediums decreased. The data suggest that the integral toxicity of soil and water contaminated with petroleum and oil products and toxicity change during biodestruction of these pollutants can be analyzed by using plant test organisms.

[Development and testing of "Ekosorb" biosorbent based on association of petroleum-oxidizing bacteria for purifying petroleum-polluted soils]. / Razrabotka i ispytaniia biosorbenta "Ekosorb" na osnove assotsiatsii nefteokisliaiushchikh baketerii dlia ochistki neftezagriaznennykh pochv.

A biosorbent containing an association of oil-oxidizing bacteria as a main constituent was developed, in which Lessorb, a product of moss and wood thermal processing, was used as a carrier. Xeroprotectors preserving the cell viability and oil-oxidizing activity in the biosorbent on drying and after long-term storage were selected. The use of this biosorbent for cleaning oil-polluted sod-podzol soils showed a two-threefold cleanup rate acceleration at different pollution levels (8 and 24 l/m2), especially in the presence of a nitrogen-phosphate fertilizer. The biosorbent increased the populations of certain groups of soil microorganisms and the total soil biological activity.

[Chemical-microbiological diagnosis of stress-corrosive damage to pipelines]]. / Khimiko-mikrobiologicheskaia diagnostika stress-korrozionnykh povrezhdenii magistral'nykh truboprovodov.

Samples of soil, ground, electrolyte, corrosion products, and protective coating were taken after excavating pipelines. The depth of stress corrosion cracks of the pipe steel was mostly related to the numbers of sulfate-reducing and denitrifying bacteria. In certain types of soil, damage correlated with the number of acid-producing microorganisms and aerobic chemoorganotrophs (saprophytes). A correlation was found between the extent of stress-corrosion damage to pipelines and the contents of reduced iron, sulfides, and organic carbon in surrounding ground.

[Direct quantitative method for evaluating the effect of biocides on Pseudomonas fluorescens in different culture media]. / Priamoi kolichestvennyi metod otsenki deistviia biotsidov na Pseudomonas fluorescens na raznykh pitatel'nykh sredakh.

A method for quantitative evaluation of the effects of biocides is presented. The method was tested in experiments with Pseudomonas fluorescens grown on various agar nutrient media. The effective concentrations of biocides that decreased the maximum specific rate of the colony biomass growth (mu'm) were called S (suppressing) concentrations, and concentrations that decreased the number of colony-forming units (CFU) were taken as L (sublethal) concentrations. The efficiency of the reported approach was demonstrated in experiments with three biocides tested in four nutrient media. It was found that the biocide sensitivity of Pseudomonas fluorescens varied by a factor of 30, depending on the amount and the type of the nutrient substrate.

[Increase in the ecological danger upon the use of biocides for fighting corrosion induced by microorganisms]. / Povyshenie ékologicheskoi bezopastnosti pri ispol'zovanii biotsidov dlia bor'by s korroziei, indutsiruemoi mikroorganizmami.

Five synergistic combinations of biocides were found, among which the combination of kathon + copper sulfate was the most efficient against Serratia marcescens. Depending on the ratio of these biocides, the synergistic effect of this pair allowed 4-20-fold decreases in the effective concentrations. Combinations of biocides with salts (carbonates and phosphates) that facilitate passivation of steel were found, which considerably decreased the corrosion losses of mild steel in comparison to isolated treatment with biocides or salts. The data showed that biocides must be added to corrosion-prone systems simultaneously with the beginning of their exploitation. Otherwise, considerably excessive amounts of biocides or their synergistic compositions are needed.

[Creation and use of a liquid substance based on association of petroleum-oxidizing bacteria]. / Sozdanie i primenenie zhidkogo preparata na osnove assotsiatsii nefteokisliaiushchikh bakterii.

An association of four bacterial strains with high oil-oxidizing and bioemulsifying activities, psychrophilicity, resistance to chemical pollutants, and lack of pathogenicity was selected from a collection of natural oil-oxidizing microorganisms. A new liquid preparation containing stabilizers and preservatives that maintain the cell viability and oil-oxidizing activity during long-term storage was developed. A field experiment in oil-polluted sod-podzol and clay sand soils demonstrated that this preparation accelerated the biodegradation of oil and its individual fractions, especially in the presence of mineral and organic fertilizers. Treatment of oil-polluted soil with this preparation and additives decreased the oil-induced suppression of certain groups of soil microflora.

[Simplified model of increase in colony diameter during growth of unicellular microorganisms and its use in evaluating the effect of biocides on microbial cells]. / Uproshchennaia model' rosta diametra kolonii odnokletochnykh mikroorganizmov i ee ispol'zovanie dlia otsenki vozdeistviia biotsidov na mikrobnye kletki.

A simplified model of increase in colony diameter is proposed. The model uses the size of single cells and several measurements of colony diameter during linear growth for calculating with good approximation the growth curve for the culture from the moment of inoculation. The parameter mu(m)', which is approximately 10% lower than the maximum specific growth rate of the colony biomass, could be also calculated. The effect of copper sulfate on the colony growth of Pseudomonas sp. G-1 was studied using the model. A high concentration of Cu2+ ions was found to result in decreases in the value of mu(m)', colony diameter, and the rate of increase in the colony diameter.

[Effect of water pollution by oil and oil products on barrier functions of bacterial cell cytoplasmic membranes]. / Vliianie zagriazneniia vodnoi sredy neft'iu i nefteproduktami na bar'ernye svoistva tsitoplazmaticheskikh membran bakterial'nykh kletok.

The effects of oil, diesel fuel, and kerosene on the electroorientational spectra and osmo-optical characteristics of bacterial cells were studied. Electroorientational spectra were found to be affected over the entire frequency range studied; changes in low-frequency (< 100 kHz) electroorientation were related to alterations in the cell surface, and those in high-frequency electroorientation, to the impairment of the barrier function of the plasma membrane. The membranotropic activity of petroleum products was also demonstrated by the osmo-optical method. Of nine bacterial species studied, Pseudomonas fluorescens VKM B-894, P. oleovorans VKM B-1522, and P. stutzeri VKM B-903 were most susceptible to the membranotropic action of kerosene; P. putida VKM B-1292 was the most resistant. Other bacterial strains studied were moderately sensitive.

[Transport of amino acids and calcium in the fungus, Phytophthora infestans].

Amino acid transport in the cells of calcium-dependent fungus Phytophthora infestans has been largely studied with respect to phenylalanine. It is defined as an active process in a number of characteristics. The reasons for that are as follows: 1) accumulation of amino acids is inhibited by carbodiimide and ruthenium red, which suggests the participation of an intermediate; 2) the transport is energy-dependent, since it is inhibited by potassium cyanide, sodium azide and 2,4-dinitrophenol. Cold-osmotic shock results in the inhibition of the amino acid and glucose transport 20-80 times without inhibiting calcium transport. The data obtained suggest that the transport systems of amino acids and calcium are probably not interrelated.

Energy-dependent transport of manganese into yeast cells and distribution of accumulated ions.

Manganese transport into yeast cells is energy-dependent. It is dependent on endogenous sources of energy and is inhibited by olygomycin (12.5-25 microgramg/ml), 2,4-dinitrophenol (1 mM), 2-deoxyglucose (1-50 mM) and sodium azide (1-10 mM), but is stimulated by cyanide and glucose. The stimulating effect of glucose is eliminated by N-ethylmaleimide and iodoacetate, which apparently inhibit the transport of glucose itself. About 75% of the manganese accumulated in the presence of glucose is found in yeast protoplasts and nearly 25% in the cell walls. A major portion of the accumulated manganese is found in vacuoles. The concentration of osmotically free manganese in the cytosol did not exceed 2 mM, but the concentration in vacuoles was up to 14 mM. The tonoplast is assumed to have a transport system for divalent cations, thereby regulating their concentration in the cytosol.