Russian Kefir Grains Microbial Composition and Its Changes during Production Process.

By combining DGGE-PCR method, classical microbiological analysis and light- and electron microscopic observations, it was found that the composition of microbial communities of central Russia regions kefir grains, starter and kefir drink include bacteria of the genera Lactobacillus, Leuconostoc and Lactococcus, and yeast anamorphs of the genera Saccharomyces, Kazachstania and Gibellulopsis. Fifteen prokaryotic and four eukaryotic pure cultures of microorganisms were isolated and identified from kefir grains. It has been shown that members of the genus Lactobacillus prevailed in kefir grains, whereas strains Leuconostoc pseudomesenteroides and Lactococcus lactis dominated in the final product - kefir drink. Yeasts contained in kefir grains in small amounts have reached a significant number of cells in the process of development of this dairy product. The possibility of reverse cell aggregation has been attempted in a mixed cultivation of all isolated pure cultures, but full formation kefir grains is not yet observed after 1.5 years of observation and reinoculations.

[Surviving Forms in Antibiotic-Treated Pseudomonas aeruginosa].

Survival of bacterial populations treated with lethal doses of antibiotics is ensured by the presence of very small numbers of persister cells. Unlike antibiotic-resistant cells, antibiotic tolerance of persisters is not inheritable and reversible. The present work provides evidence supporting the hypothesis of transformation (maturation) of persisters of an opportunistic pathogen Pseudomonas aeruginosa revealed by ciprofloxacin (CF) treatment (25-100 µg/mL) into dormant cystlike cells (CLC) and non-culturable cells (NC), as was described previously for a number. of non-spore-forming bacteria. Subpopulations of type 1 and type 2 persisters, which survived antibiotic treatment and developed into dormant forms, were heterogeneous in their capacity to form colonies or microcolonies upon germination, in resistance to heating at 70 degrees C, and in cell morphology Type 1 persisters, which were formed after 1-month incubation in the stationary-phase cultures in the medium with decreased C and N concentrations, developed in several types of surviving cells, including those similar to CLC in cell morphology. In the course of 1-month incubation of type 2 persisters, which were formed in exponentially growing cultures, other types of surviving cells developed: immature CLC and L-forms. Unlike P. aeruginosa CLC formed in the control post-stationary phase cultures without antibiotic treatment, most of 1-month persisters, especially type 2 ones, were characterized by the loss of colony-forming capacity, probably due to transition into an uncultured state with relatively high numbers of live intact cells (Live/Dead test). Another survival strategy of P. aeruginosa populations was ensured by a minor subpopulation of CF-tolerant and CF-resistant cells able to grow in the form of microcolonies or regular colonies of decreased size in the presence of the antibiotic. The described P. aeruginosa dormant forms may be responsible for persistent forms in bacteria carriers and latent infections and, together with antibiotic-resistant cells, are important as components of test systems to assay the of efficiency of potential pharmaceuticals against resistant infections.

[Identification of Target Extracellular Proteases--Activators of Proteins of Haemostasis System Produced by Micromycetes Aspergillus ochraceus and Aspergillus terreus].

Effects of extracellular proteases of Aspergillus ochraceus and Aspergillus terreus on plasma hemostasis proteins, consist of initiating the activation of prothrombin complex proteins, was detected. Was discovered, that A. ochraceus proteases have a direct influence on protein C and coagulation factor X, and A. terreus proteases causes their activation indirectly through kallikrein system stimulation. The ability of extracellular proteases of micromycetes activate prekallikrein in human blood plasma on the example of A. terreus was first demonstrated.

[Methanogenic destruction of (amino)aromatic compounds by anaerobic microbial communities].

Destruction of a number of aromatic substrates by anaerobic microbial communities was studied. Active methanogenic microbial communities decomposing aminoaromatic acids and azo dyes into CH4 and CO2 were isolated. Products of primary conversion were found to be 2-hydroxybenzyl and benzyl alcohols gradually transforming into benzoate. It was shown that isolated microbial communities are capable of converting the initial substrates--benzyl alcohol, benzoate, salicylic acid, and golden yellow azo dye--into biogas without a lag-phase but with different velocities. Aromatic and linear intermediates of biodestruction of aromatic amines by obtained enrichment cultures were determined for the first time. Selective effect of aromatic substrates on a microbial community that was expressed in decrease in diversity and gradual change of dominant morphotypes was revealed.

[Special traits of decomposition of azo dies by anaerobic microbial communities].

We present the results of an investigation into the special traits of conversion of azo dies golden yellow, acid orange, methyl orange, and methyl red under anaerobic conditions in comparison to aerobic conditions. In the presence of oxygen, only methyl red underwent decomposition, while under oxygen-free conditions, all remaining substances were fully discolored under the action of a methanogenous consortium of organisms. The products of reduction of the azo bond are determined in the case of each die. Introduction of additional acceptors of electrons (sulfate and nitrate) had a negative influence on the discoloration of azo dies. Addition of ethanol as an available organic cosubstrate accelerated decomposition of azo dies both under methanogenous and sulfate- and nitrate-reducing conditions. There is no direct correlation between the rates of conversion of azo dies under anaerobic conditions or their toxicity to acetoclastic methanogens. Changes in the morphological composition of the community discoloring an azo die depended on the duration of its impact on microorganisms. The mechanism of the reduction of the azo bond under the action of substances acting as mediators is explained. These substances are products of the metabolism of the microbial community in anaerobic conditions. It is shown that the supposed mediators NADH and sulfide efficiently discolor azo dies in a cell-free system, while riboflavin significantly increased the rate of conversion of substrates in recurrent cycles of discoloration only in the presence of an anaerobic microbial consortium.

[Anaerobic microbial associations degrading aromatic amino acids].

Anaerobic microbial associations have been isolated that degrade aromatic amino acids to methane and carbon dioxide at high rates. Significant differences between the morphological, cytological, and physiological traits of cultures isolated from samples of adapted and unadapted sludge are shown. The effects of cultivation temperature, illumination, and presence of mineral nitrogen and bicarbonate in the medium upon adaptation of enrichment cultures to substrates and subsequent behavior of the anaerobic associations have been studied. Intermediate and final products of degradation of aminoaromatic compounds and the sequence of their formation in the cultures have been determined. We have also studied the effects of exogenous electron acceptors and additional carbon sources on the degradation of aminoaromatic compounds.

[Novel L-glutamate oxidase producing organisms: Streptomyces litmocidini and Streptomyces cremeus]. / Novye produtsenty L-glutamatoksidazy-Streptomyces litmocidini i Streptomyces cremeus.

Two novel strains i.e. Streptomyces cremeus 510 and Streptomyces litmocidini 447 producing L-glutamate oxidase were isolated from soil samples and identified. Mathematical design of the experiments made it possible to optimize the fermentation medium composition which provided at least a 5-fold increase of the strain L-glutamate oxidase activity by comparison with the initial activity in the standard medium.

[The use of preparations of protozoan origin as agents for the prevention and early therapy of combined radiation-thermal injuries]. / Ispol'zovanie preparatov protozoinogo proiskhozhdeniia v kachestve sredstv profilaktiki i rannei terapii kombinirovannykh radiatsionno-termicheskikh porazhenii.

Radioprotective and therapeutic effects of astazian and astazilide, the drugs of protozoan origin, were studied in comparison with known modifiers of biological reactions (bacterial polysaccharides, synthetic polypeptides) in combined radiation-thermal injuries (CRTI). The efficiency of drugs under examination was found to be time- and dose-dependent. Application of the drugs of protozoan nature 24 hours prior to or 1 hour following CRTI provided 30 to 50% survival of experimental animals for 30 days as compared to 4.5% in the group of untreated mice. Administration of the drugs 3-7 days following CRTI exerted no therapeutic effect.

[Combined immobilized cultures producing fibrinolytic proteinases]. / Kombinirovannye immobilizovannye kul'tury, produtsiruiushchie fibrinoliticheskie proteinazy.

The authors obtained combined immobilised systems composed of a culture producing fibrinolytic proteinases and a stimulating strain. The optimal ratio between the two cultures in gel was selected at a high starting cell density. Highly stable immobilised cultures were produced by growing the cells in gel particles. The interrelationship of the partners was studied in the binary immobilised culture. The biosynthetic activity of the system fell down to the level of a monoculture when the cells of the stimulating strain were eliminated from gel. The producing and stimulating strains are at equilibrium in associative immobilised cultures obtained by growing the cells in gel, and Arthrobacter is not eliminated. The mechanism of biosynthesis stimulation in a combined immobilised culture has been studied. Apparently, the procedure of immobilisation and the action of a stimulating compound exert the synergistic effect.