Chemically defined media for growing anaerobic bacteria of the genus Veillonella

A chemically defined medium for Veillonella parvula and V. alcalescens is described. Some nutritional aspects of the two strains used were examined: the optimum concentration of reducing agents, the requirement for amino acids, diamines, vitamins and other growth factors, and the conditions needed for well balanced nutrition.No specific requirements for single amino acids were observed. A combination of l-cysteine, dl-aspartic acid, l-glutamic acid, l-serine and l-tyrosine, promoted growth. In V. alcalescens, serine could substitute both arginine and tryptophan (or histidine). No growth was obtained with ammonium salts as the sole N source.Decarboxylation of l-ornithine, l-lysine and l-arginine was not demonstrated in the Veillonella parvula strain, which required putrescine or cadaverine for growth. Spermine, spermidine, l-lysine, l-ornithine and l-arginine, could not substitute putrescine in Veillonella parvula. Veillonella alcalescens, which does not require putrescine in the medium, was able to decarboxylate l-ornithine while forming putrescine.     

Carbon dioxide evolution by bacteria of the genus Enterobacter that utilize glucose and glycerin

The activity of decarboxylase from two bacterial species belonging to the genus Aerobacter was studied in media containing different carbon sources. It has been shown that A. aerogenes and A. cloacae, in model experiments with media containing glycerol, evolve 1.2-3.5 times less CO2 (42-107 micrograms) as compared with the medium containing glucose (143-149 micrograms). The activity of decarboxylase of the bacterium in media with the tested sources of carbon correlated with the rate of acetoin biosynthesis.     

Beta-lactamase activity of bacteria of the genus Proteus]

beta-Lactamases of Proteus and their role in the mechanism of the microbe resistance to penicillins and ceporin were studied. It was found that the beta-lactamase of Proteus had low activity and were produced by both beta-lactamide resistant and sensitive clinical strains of Proteus. The resistant cultures of Proteus produced enzymes more frequently (3.4--5 times) than the sensitive ones. The synthesis of beta-lactamase in the clinical Proteus strains was inducable. The high induction coefficient was achieved only in the presence of high concentrations of the inductor. No significant dependence of the culture sensitivity level of ampicillin and ceporin on the induction level was observed. The most significant part of the constitutive enzyme in Proteus was intracellular, while that of the inducable enzyme was extracellular. No correlative dependence between the culture resistance levels to penicillins and ceporin and the enzyme activity was noted. The beta-lactamase activity was not found in the transconjugants with the in vitro acquired R-factor controlling the ampicillin and ceporin resistance, as well as in the resistant mutants selected on the media with increasing concentrations of the above antibiotics. Induction of beta-lactamase synthesis was not found in these strains either. The ability of Proteus to synthesize beta-lactamase can be lost on the strain storage under laboratory conditions which was not always accompanied by reduction of the culture sensitivity to ampicillin and ceporin. The enzymatic destruction of beta-lactamides was not the main mechanism of Proteus resistance to the above antibiotics.     

The antilysozyme activity of bacteria in the genus Klebsiella

The ability to inactivate lysozyme was found in representatives of three species of the genus Klebsiella bacteria: K. pneumoniae (117 strains), K. rhinoscleromatis (104 strains), K. ozaenae (90 cultures). The test cultures displayed a different antilysozyme activity, inactivating from 2 to 30 micrograms/ml of the enzyme. Taking into account the lysozyme role in the immunity and chitin synthesis processes in the organism of insects, the inactivation of the enzyme by Klebsiella may be considered as one of possible mechanisms of the entomopathogenic action of these bacteria.     

Biofilm formation in environmental bacteria is influenced by different macromolecules depending on genus and species

The formation of biofilms by diverse bacteria isolated from contaminated soil and groundwater on model substrata with different surface properties was assessed in a multifactorial screen. Diverse attachment phenotypes were observed as measured by crystal violet dye retention and confocal laser scanning microscopy (CLSM). Bulk measurements of cell hydrophobicity had little predictive ability in determining whether biofilms would develop on hydrophobic or hydrophilic substrata. Therefore selected pairs of bacteria from the genera Rhodococcus, Pseudomonas and Sphingomonas that exhibited different attachment phenotypes were examined in more detail using CLSM and the lipophilic dye, Nile Red. The association of Rhodococcus sp. cell membranes with lipids was shown to influence the attachment properties of these cells, but this approach was not informative for Pseudomonas and Sphingomonas sp. Confocal Raman Microspectroscopy of Rhodococcus biofilms confirmed the importance of lipids in their formation and indicated that in Pseudomonas and Sphingomonas biofilms, nucleic acids and proteins, respectively, were important in identifying the differences in attachment phenotypes of the selected strains. Treatment of biofilms with DNase I confirmed a determining role for nucleic acids as predicted for Pseudomonas. This work demonstrates that the attachment phenotypes of microbes from environmental samples to different substrata varies markedly, a diverse range of macromolecules may be involved and that these differ significantly between genera. A combination of CLSM and Raman spectroscopy distinguished between phenotypes and could be used to identify the key macromolecules involved in cell attachment to surfaces for the specific cases studied.     

Fibrinolytic activity of bacteria from Pseudomonas genus]

A strain of the genera Pseudomonas genera was found to possess hemolytic, fibrinolytic and thrombolytic activities. The fibrinolytic activity of the lyophilized unpurified preparation was 900 conventional units/mg. After incubation in the blood plasma, the activity completely remained. The preparation (1 microgram/ml, 750 micrograms of protein) obtained by precipitation with ammonium sulfate (80% saturation) completely lysed in vitro human blood thrombi for 50 min. The strain studied can find practical applications in medical industry.     

Effects of suboptimal environmental conditions on immobilized bacteria growing in continuous culture

Two immobilized bacterial cultures with the ability to metabolize 6-amino-2-naphthalenesulfonic acid (6A2NS) and 2-naphthalene-sulfonic acid (2NS) were investigated under suboptimal environmental growth conditions. The cultures were employed in continuously operated airlift loop-reactors. The physico-chemical growth parameters such as pH, temperature and dissolved oxygen concentration were varied. It was found that a decreasing growth rate in suboptimal conditions was compensated by increasing biomass concentration over a wide range. Operated continuously for more than 20 months, the 6A2NS-degrading system appeared to be reliable. After pH-shockloadings and long-term oxygen default, the immobilized microorganisms recovered almost immediately and stable operating conditions were achieved again within less than 48 h. These remarkable results were sustained with the 2NS degrading system.     

Alteration of phagocyte functional activity depending on the presence of pR50 plasmid in bacteria

The relationship between the presence, or the absence, of conjugative plasmid pR50 detected in Klebsiella oxytoca 89, in the isogenic pairs of attenuated strains Shigella flexneri 2a 516 Near and Salmonella typhimurium 129 Rifr and the regeneration of the active forms of oxygen by mouse peritoneal phagocytizing cells was studied. As indicated by the data obtained in the course of the experiment, plasmids pR50 could influence the chemiluminescent response of phagocytes. The inhibition of the synthesis of oxygen metabolites was found to occur at the primary stage of the infectious process, that later this synthesis increased, that facilitated the survival of the animals infected with the cultures carrying plasmid pR50.     

Detection of cellulolytic activity of bacteria and fungi growing on agar surfaces

Summary Cellulolytic activity of four fungal species growing on solid medium containing acid-swollen cellulose could be detected much more easily if fungal growth was partly inhibited by the detergent Triton X-100. The dye, aniline blue-black, did not affect growth but increased the sensitivity of detection of cellulolytic activity of both fungi and bacteria. Separating fungi from cellulose fibres by a layer of agar or by filters showed that cell-fibre contact is not necessary for cellulose degradation. Such degradation is clearer when contact is prevented.     

State of several parts of immune system in mice, infected by enterotoxigenic bacteria of Enterobacter genus

Influence of thermolabile enterotoxin bacteria of Enterobacter genus on the immune system of mice was studied. Assessment of phagocytic functions of the immune system as well as antigen-presenting functions of macrophages during infection with enterotoxin-producing strains of bacteria from Enterobacter genus revealed pleiotropic effect of the toxin which is characterized by inhibition of antigen-presenting and processing functions of macrophages.     

The effect of the cultivation conditions on lectin production by representative bacteria in the genus Bacillus

Dynamics of the lectin activity accumulation in the culture liquid was studied through the example of certain representatives of spore-forming aerobic bacteria in the process of their growth. The environmental factors (the temperature, pH value, the presence of definite carbohydrates in the medium) were investigated for their effect on the biosynthesis of extracellular lectins by producers. Based on these studies it was possible to establish optimal conditions of cultivation and to obtain the high specific lectin activity of the culture liquid for each strain.     

Antagonistic activity of bacteria from Bacillus genus against dermatophyte fungi

Antagonistic properties of the strain Bacillus subtilis IB-54 with respect to dermatophyte fungi Trichophyton rubrum, T. mentagrophytes var. gypseum, Microsporum canis was studied. The studied strains of bacilli effectively inhibited growth and development of dermatophytes when were cultivated on the media containing different carbon sources. Experiments on laboratory animals showed that B. subtilis IB-54 displayed no virulence, toxicity, and toxigenicity and can be considered as perspective object for development of antimycotic drugs.     

Screening of plasmids in the bacteria of the genus Bacillus with antilysozyme activity

In the study of the microbiocenosis of the distal section of the patients' large intestine Bacillus strains with antilysozyme activity (ALA) were isolated. In B. cereus strain 26 with pronounced expression of antilysozyme factor the plasmid sized approximately 100 kb was detected. The transformation of the isolated plasmid in cells of B. cereus non-plasmid strain IP5832 the localization of genes encoding ALA and resistance to kanamycin was determined. The production of ALA factor in the recombinant clone of B. cereus strain IP5832 corresponded to the clinical isolate of B. cereus 26. The replicon of the detected plasmid could be used for the determination of the coding sequence of the antilysozyme sign of bacilli. Genetic determinants of antilysozyme factors and kanamycin resistance may be used for the construction of vector systems of cloning in bacilli.     

Sensitivity of Proteus hauseri bacteria to chemotherapeutic preparations depending on the cultivation conditions and on the composition of the nutrient medium]

Sensitivity of 227 Proteus strains isolated from patients was studied comparatively using the agar-diffusion method (disks) and the method of serial dilutions. Marked differences in the numbers of the strains resistant to benzylpenicillin and chloramphenicol were found with the above methods. It was shown that the ingredients of Ploskirev's medium significantly (by 2.8--13.5 times) inhibited the antibacterial activity of streptomycin, neomycin, monomycin, kanamycin, ampicillin and nalidixic acid and had practically no effect on the activity of benzylpenicillin, chloramphenicol and furazolidone. The values of the MIC of the drugs used in the experiment with liquid media correlated with those obtained with Sabouro's medium, which provided recommendation of the latter for determination of Proteus sensitivity by the method of serial dilutions in the solid medium, Cultivation of Proteus at a temperature of 40 degrees C resulted in a decrease of the resistance to most of the drugs tested by (by 3--12.4 times).     

Impact of heavy metals on the trophic activity of daphnia depending on feeding conditions and age of crustaceans

This paper studies how exposure conditions affect the trophic activity of Daphnia crustaceans and their sensitivity to heavy metals. To register the trophic activity of crustaceans, the change in intensity of the zero level of rapid fluorescence in chlorella alga utilized as feed is used. The optimal conditions (stocking density, age of test organisms, feeding schedule, and exposure time) are determined under which a high level of the trophic activity and sensitivity of crustaceans to pollution are registered. An experimental design is suggested in which crustaceans are first exposed to a toxicant and then a suspension of the alga is introduced into a cultivation medium.