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D N Ostrovskiĭ

Publications and source records attributed to D N Ostrovskiĭ.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

[Immunomodulatory properties of 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate and search for its new derivatives].

A strong immunomodulatory effect of 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEC) responsible for the survival of bacteria was shown on isolated macrophages and in experimental infections in mice (typhoid and tularemia). Derivatives of MEC were found by 1H-NMR spectroscopy under stress conditions in colorless mutants of the bacteria and isolated to be subsequently purified and used for modulation of the immune system of animals.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Effect of levomycetin (chloramphenicol) on the biosynthesis of membrane proteins, structure and some functions of Micrococcus lysodeikticus bacterial membranes].

Levomycetin (chloroamphenicol), an inhibitor of protein synthesis, caused drastic changes in the molecular organization of bacterial membranes being introduced into the cultural medium of Micrococcus lysodeikiticus (50-100 mkg/ml. Isolated membranes of levomycetin-treated cells are enriched with lipids as compared with the control, they are more labile and they lose the X protein component and a considerable part of dehydrogenases, which results in the significant inhibition of all the respiration chain. At the same time the content of cytochrome alpha was increased by 17%, and the activity of malate dehydrogenase (as estimated in cell lysates) was two-fold increased in levomycetin-treated cell as compared with the control. It means that biosynthesis of some membrane proteins can be twice more resistant to the action of the antibiotic than the biosynthesis of other proteins, the total protein biosynthesis being significantly depressed (the incorporation of labelled leucine in membrane proteins is inhibited by 78%, and in cytoplasmic proteins-by 83%). The ratio of the respiration rate of intact levomycetin-treated cells to the protein content or to the cell bulk was similar to that of the control culture, which testifies the stability of membranes in vivo even under considerable "fattening". The loss of dehydrogenases and the X protein from the membranes apparently takes place at the moment of the cell rupture during the lysis in hypotonic medium. The ratio of the respiration rate of intact levomycetin-treated cells to the content of cytochromes a, b, c was 1.15-1.55 times as low as that of control cells which is probably due to the tendency of respiration components to the independent translocation in the membrane and is the result of the decrease in the concentration of the respiration components under the less than fattening greater than of the membrane.

Bacterial Proteins↗
PubMedDate not supplied

[Lateral diffusion of the protein components of the respiratory assembly of Microsoccus lysodeikticus].

Preparations with a selectively decreased (by 85-90%) content of NADH dehydrogenase were isolated by means of heating treatment of M. lysodeikticus isolated membranes. The degree of the reduction of the NADH dehydrogenase nearest neighbour in the respiration chain of cytochrome b556 in heated membranes is similar to that in intact membranes. It is concluded that cytochrome b556 and (or) NADH dehydrogenase are capable to lateral migration in the membrane of M. lysodeikticus, resulting in the inter-chain electrone transport. A coefficient of their lateral diffusion is calculated (D equals 8-10(-10)-2-10(-9) CM2SEC-1 At 30 degrees C) on the basis of kinetics of cytochrome reduction by NADH dehydrogenase. The electron transport, due to a diffusion of respiration carriers from one assambly to another, proceeds 100 times as slow as the electrone transport in the respiratory chain. The data obtained allow to consider the aggregation of respiration enzymes as a dynamic formation.

Biological Transport↗
PubMedDate not supplied

[Properties of 2-C-methyl-D-erythritol 2,4-cyclopyrophosphate--an intermediate in the non-mevalonate isoprenoid biosynthesis].

Extraction and purification from the biomass of Corynebacterium ammoniagenes of 2-C-methyl-D-erhythritol 2,4-cyclopyrophosphate (MEC) was associated with its spontaneous transformation into a number of derivatives (which was due to pyrophosphate bond lability and the formation of complexes with metals). These derivatives included 1,2-cyclophospho-4-phosphate, 2,4-diphosphate, 2,3-cyclophosphate, 1,4-diphosphate, and 3,5-diphosphate (identified by 1H, 31P, and 13C NMR spectroscopy) and accounted for about 10% MEC. When added to a solution of DNA in the presence of the Fenton reagent, MEC prevented DNA decomposition. In addition, MEC slowed down the interaction of the reagent with tempol radicals, which indicates that complexation of ferrous ions by MEC attenuates their ability to catalyze the formation of hydroxyl radicals from hydrogen peroxide. In the presence of 0.23 mM MEC, the rate of respiration of rat liver mitochondria increased 1.8 times. At 0.1-1.0 mM, MEC activated in vitro proliferation of human Vgamma9 T-cells. It is suggested that MEC acts as an endogenous stabilizing agent for bacterial cells subjected to oxidative stress and as an immunomodulator for eukaryotic hosts.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Free radicals in mercury-resistant bacteria indicate a novel metabolic pathway].

A mercury resistant-soil bacterium P.10.15, identified as a close relative of Pseudomonas veronii, was shown to accumulate a specific compound in the stationary phase of growth. This compound is converted to a long-lived free radical under oxidizing conditions, as registered by its EPR signal at room temperature. The compound was purified by ion-exchange and gel-filtration chromatography and identified by mass spectroscopy, 2D NMR, and EPR as a trisaccharide beta-D-GlcpNOH,CH3-(1-->6)-alpha-D-Glcp-(1-->1)-alpha-D-Glcp, or, in other words, as 6-O-(2-deoxy-2-[N-methyl]hydroxylamino-beta-D- glucopyranosyl)-alpha-alpha-trehalose, previously discovered in Micrococcus luteus (lysodeikticus) and named lysodektose. The compound is suggested to be a novel intermediate of a previously unknown basic metabolic pathway of trehalose transformation in bacteria, a potential target for antibacterial drug development.

Chromatography, Gel↗
PubMedDate not supplied

[Prevalence of nonmevalonate and mevalonate pathways for isoprenoid biosynthesis among bacteria of different systematic groups].

The effect of fosmidomycin and mevinoline, inhibitors of the nonmevalonate and the mevalonate pathway of isoprenoid biosynthesis, respectively, on the growth of 34 anaerobic and 10 aerobic prokaryotic strains was studied. Fosmidomycin at the concentrations used was shown to inhibit the growth of 9 (of 10) representatives of the family Microbacteriaceae, 4 (of 5) strains of Thermoanaerobacter, and 11 (of 12) strains of Clostridium, whereas mevinoline inhibited the growth of lactobacilli (Carnobacterium), methanogenic and sulfate-reducing bacteria insensitive to fosmidomycin. During the late growth phase, four strains of actinobacteria (of nine) accumulate the compound, which, upon oxidation, generates a long-lived free radical; three strains synthesize 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEC). It was concluded that the difference in the sensitivity of the organisms to fosmidomycin and mevinoline might serve as a test to differentiate several representatives of the family Microbacteriaceae. The use of mevinoline for inhibiting methanogens in ecological investigations seems to be promising.

Bacteria↗
PubMedDate not supplied

[Isoprenoid pigments in representatives of the family Microbacteriaceae].

By using fosmidomycin and mevinolin (inhibitors of the synthesis of isoprenoid pigments), spectrophotometry, and mass spectrometry, the presence of isoprenoid pigments is shown in 71 of the 78 strains under study. All of these strains belong to 11 genera of the family Microbacteriaceae. Yellow, orange, and red pigments are found to have absorption spectra typical of C40-carotenoids. Eight out of the sixteen strains of the genus Microbacterium are able to synthesize neurosporene, a precursor of lycopene and beta-carotene. The biosynthesis of carotenoids in some representatives of the genera Agromyces, Leifsonia, and Microbacterium is induced by light. Inhibition of the biosynthesis of isoprenoid pigments by fosmidomycin suggests that they are synthesized via the nonmevalonate pathway. Twelve strains are found to exhibit both the nonmevalonate and mevalonate pathways of isoprenoid synthesis. These data, together with the difference in the inhibitory concentration of fosmidomycin, can be used for differentiating various taxa within the family Microbacteriaceae.

Actinomycetales↗
PubMedDate not supplied

[Comparative characteristics of the metabolism of E. coli cells with various activity of penicillin acylase].

A correlation between the synthesis and secretion of penicillin acylase (PA; EC 3.5.1.11) and the membrane phospholipid composition was observed in three E. coli strains. In cells with overproduction of PA, the phospholipid/protein ratio decreases, while the cardiolipin/phosphatidylglycerol ratio increases. The differences in the functioning of the electron transport system were revealed in cells with different levels of PA synthesis and secretion. The O2 consumption rate was 3 times lower in the cells with overproduction of PA than in those of less productive strains. On the contrary, membrane particles isolated from the cells of PA producers had no significant differences in the O2-reduction rate. The sensitivity of the strains to the inhibitor of terminal oxidases, sodium cyanide, and to the uncoupler of redox phosphorylation, chlorocarbonyl-phenylhydrazone, was different. Thus the E. coli cells with PA overproduction are characterized by significant changes in energetics and constructive metabolism. The interrelations between PA overproduction, phospholipid metabolism and the respiratory chain activity are discussed.

Electron Transport↗
PubMedDate not supplied

[The cell wall of Bacillus brevis producing gramicidin S, a cyclodecapeptide antibiotic].

Gramicidin S is tritiated in Bacillus brevis G.-B. intact cells by activated tritium atoms (which is indicative of its surface localisation). The cell wall protein is tritiated very weakly, which shows that it is screened, apparently, by gramicidin adsorbed on its surface. The cell wall protein is not a glycoprotein and its interaction with exogenous gramicidin S causes cell aggregation. As follows from the Rf value after the chromatographic separation of B. brevis lipids, the reaction of staining, and the data of H-NMR spectroscopy for the fraction of phospholipids, the main membrane phospholipid is an anionic acetylated phosphatidyl ethanolamine.

Bacillus↗
PubMedDate not supplied

[Membrane potential in Escherichia coli bacteria subjected to the action of low temperature freezing and blood serum complement].

The action of a blood serum complement on Escherichia coli cells or their freezing does not cause cell destruction visible in the electron microscope, but the permeability barrier is disordered and exogenous substrates can penetrate into the cell. When these exogenous respiration substrates are oxidised, the energy-dependent uptake of phenyl dicarboundecarborane (PCB-), a lipophilic anion and an indicator of the membrane potential, is observed. Apparently, the uptake of PCB- is associated with the generation of local membrane potentials when the permeability barrier of cells is damaged.

Complement System Proteins↗
PubMedDate not supplied

[Effect of pesticides on bacterial membranes].

The effect of pure preparation of ordram, fosalon, DDT, methoxychlorine, hydrel, dihydrel, 2,4-D, 2M-4C and of technical preparations of saturn, linuron, ronstar and keltan on the membrane functions (respiration and motility) of Azospirillum brasilense and Chromatium minutissimum cells and on malate and NADH oxidation by the isolated membranes of Micrococcus lysodeikticus was investigated. The effect varied from irreversible impairment to undetectable impairment of the measured activities depending on the type of bacteria and on the chemical used. The ordram induced permeability of the A. brasilense membranes without inhibition of the respiratory chain activity and selective inhibition of malate oxidase accompanied by stimulation of NADH oxidation in the M. lysodeikticus membranes indicates a possibility of ordram application as a regulator of bacterial metabolism.

Bacteria↗
PubMedDate not supplied

[Changes in the structural function of the membrane of M. lysodeikticus as affected by preparations of the bacterial autoregulatory factors D1].

Introduction of factors D1 isolated from the culture fluids of B. cereus and Ps. carboxydoflava into cytoplasmic membranes of M. lysodeikticus resulted in a higher microviscosity of the lipid phase. Factor d1 changes the ion permeability of an artificial bilayer membrane as well as reduces the content of free water in the bacterial paste. It is assumed that registered structural changes may result from the interaction of the factor molecules with membrane lipids and be the main reason of changes in the functioning of membrane-bound enzymes and dehydration of the microbial cell as well.

Bacillus cereus↗