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Biomedical subjects

V V Ignatov

Publications and source records attributed to V V Ignatov.

At least 37 records · Page 2Linked to original sources
PubMed1975

[The role of the carotenoid pigments of staphylococcus in the response of cells to temperature changes].

A study was made of the reaction of the membranous apparatus of the pigmented strains of staphylococcus 209-P and its four apigmented variants to the action of various temperatures measured by the exit from the cells of the low molecular components. Permeability of the cell membranes in case of the action of the extreme temperatures of the 209-P strain altered much more than that of the apigment variants. It is supposed that the carotinoid pigments of the apathogenic staphylococci took part in the formation of functional lability of the bacterial membranes.

Carotenoids↗
PubMed1975

[Acetyl-CoA-synthetase activity of pigmented staphylococci].

In 19 strains of staphylococci a study was made of the activity of acetyl-CoA-synthetase reaction. All the strains possessed an active enzymatic system transforming the acetate into an active form. The activity of acetyl-CoA-synthetase proved to be much greater in the pigmented staphyloccus strains than in the nonpigmented ones. It is supposed that there existed an association between the acetyl-CoA-synthetase and the biogenesis of carotinoid pigments in Staph. aureus.

Acetate-CoA Ligase↗
PubMedDate not supplied

[Hemagglutinating activity of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler]].

The hemagglutinating (HA) activity of the submerged mycelium and the culture liquid (CL) of four strains of Lentinus edodes was studied. The HA activity of CLs proved to be much higher than that of mycelia. The carbohydrate specificity of fungal agglutinating factors was determined. HA activity was investigated as a function of the inoculum size, cultivation temperature, and culture age. The agglutinating activity of different morphogenetic structures of L. edodes F-249, including mycelium, brown mycelial mat (MM), primordia, and fruiting bodies, was studied, MM was found to possess the maximum HA activity, which can be explained by the possible involvement of agglutinins in the formation of MM, which is composed of glued hyphae.

Carbohydrate Metabolism↗
PubMedDate not supplied

[Initial stages of interaction of Azospirillum brasilense bacteria with wheat germ roots: adsorption, deformation of root hairs].

The initial stages of colonization of wheat roots by cells of Azospirillum brasilense strains 75 and 80 isolated from soils of the Saratov oblast were studied. The adsorption of azospirilla on root hairs of soft spring wheats rapidly increased in the first hours of incubation, going then to a plateau phase. Within the first 15 h of incubation, exponential-phase cells were adsorbed more intensively than stationary-phase cells. Conversely, stationary-phase cells were adsorbed more intensively than exponential-phase cells, if the period of azospirilla incubation with the wheat roots was extended. As the time of incubation increased, the attachment of azospirilla to the wheat roots became stronger. The effect of cell attachment to root hairs was strain-dependent; the number of adsorbed cells of a given strain of azospirilla was greater in the case of host wheat cultivars. The deformation of wheat root hairs was affected by the polysaccharide-containing complexes isolated from the capsular material of azospirilla. The suggestion is made that common receptor systems are involved in the adsorption of azospirilla on roots and in root hair deformation.

Azospirillum brasilense↗
PubMedDate not supplied

[Destruction of chlorinated derivatives of phenol: ortho-chlorophenol, para-chlorophenol, and 2,4-dichlorophenoxyacetic acid by bacteria communities in anaerobic sludge].

The bacterial community of anaerobic sludge could degrade ortho-chlorophenol, para-chlorophenol, and 2,4-dichlorophenoxyacetic acid at concentrations as high as 100 mg/l. The time needed for the degradation of a given chlorinated phenol derivative increased 1.5- to 2-fold upon a twofold increase in its concentration (from 50 to 100 mg/l). The duration of the adaptation period depended on the compound studied and on its concentration. The degradation of 2,4-dichlorophenoxyacetic acid proceeded via 2,4-dichlorophenol and p-chlorophenol as intermediates; the degradation of o-chlorophenol occurred with the formation of phenol. The dynamics of p-chlorophenol degradation and chloride ion accumulation were studied.

2,4-Dichlorophenoxyacetic Acid↗
PubMedDate not supplied

[Study of acetyl-CoA-synthetase from staphylococcus aureus].

Acetyl-CoA-synthetase was isolated from cells of St. aureus 209-P. The method of isolation and partial purification of the enzyme is worked out. Km values of the enzyme for acetate, CoA and ATP are calculated. p-Chloromercuribenzoate and monoiodoacetate were shown to inhibit the enzyme activity. The enzyme activity is estimated depending on the age of the cell culture and on the presence of acetate in the culture medium.

Acetate-CoA Ligase↗
PubMedDate not supplied

[Respiratory activity of bacteria Acinetobacter calcoaceticus TM-31 during assimilation of alkane hydrocarbons].

The respiratory activity of Acinetobacter calcoaceticus TM-31 with resect to alkane hydrocarbons was studied. The dynamics of oxygen consumption by the cells while assimilating n-hexadecane was assayed by a modified technique using an oxygen electrode. The dependence of cell respiratory activity on the amount of n-hexadecane within the concentration range of 0.03-0.66% was determined. It was demonstrated that the cells also displayed respiratory activity towards other medium-chain n-alkanes: hexane, octane, decane, tridecane, and heptadecane. Thus, we demonstrated the possibility of determining alkanes by measuring the respiratory activities of microorganisms.

Acinetobacter calcoaceticus↗
PubMedDate not supplied

[Reserve capacities of blood coagulation and total lytic activities in patients with benign prostatic hyperplasia].

Prior to and after the double local arm hypoxia test, whole blood thromboelastography under lowered contact activation was used to examine hemostasis and total blood lytic activity in 27 males aged 59-68 years who had moderate benign prostatic hyperplasia (BPH) as assessed by the International Scale. The control group included 25 apparently healthy males. Only 40.7% of patients were found have adequate reserve capacities of the study systems. BPH induced tension of reserve capacities of total blood lytic activity in 37% of cases and their depletion in 22.3%, even then moderate symptoms of the disease occurred.

Aged↗
PubMedDate not supplied

[The role of polysaccharide-containing components of the Azospirillum brasilense capsule in adsorbing bacteria on wheat seedling roots].

Azospirillum brasilense cells deprived of capsular exopolysaccharides completely lost their ability to bind wheat germ agglutinin (WGA) and much of their ability to attach to wheat seedling roots. The decapsulation of bacterial cells by washing them with a NaCl solution led to an increase in the relative hydrophobicity of the cell surface. The pretreatment of wheat seedling roots with N-acetyl-D-glucosamine (GlcNAc) or the GlcNAc-containing polysaccharide complexes stripped from Azospirillum cells reduced their attachment to the roots. Under the experimental conditions, 3-h incubation of wheat seedling roots with exponential-phase azospirilla, bacterial adsorption is mainly driven by the attachment of the cells to the roots, whose operation is due to the capsular polysaccharide components and the WGA present on the wheat seedling roots.

Azospirillum brasilense↗
PubMedDate not supplied

[Electrooptical properties of soil nitrogen-fixing bacterium Azospirillum brasilense: effect of copper ions].

The effects of copper ions on the uptake of some essential metals in the biomass and the electrooptical properties of cell suspensions of the nitrogen-fixing soil bacterium Azospirillum brasilense sp. 245 were studied. Copper cations were shown to be effectively taken up by the cell biomass from the culture medium. The addition of copper ions increased the rate of uptake of some other metals present in the culture medium. This was accompanied by changes in the electrooptical characteristics of cell suspension as measured within the orienting electric field frequency range of 10 to 10,000 kHz. The effects observed during short-term incubation of A. brasilense in the presence of copper cations were less significant than during long-term incubation. These results can be used for rapid screening of microbial cultures for enhanced efficiency of sorption and uptake of metals.

Azospirillum brasilense↗
PubMedDate not supplied

[Proteolytic activity of lectins from the nitrogen-fixing bacterium Bacillus polymyxa].

Two lectins (LI and LII) stripped from the surface of Bacillus polymyxa 1460 cells were found to possess proteolytic activity, which was associated with their hemagglutinating activity. The inhibition of the hemagglutinating activity of lectins by specific carbohydrate haptens changed their enzyme activities. The inhibition of hemagglutinating activity by glucuronic acid or fructose 1,6-diphosphate decreased the proteolytic activities of both lectins, whereas the blocking of this activity with D-glucosamine or D-galactosamine increased the proteolytic activity of LII. The molecules of the B. polymyxa lectins are suggested to contain two active centers responsible for hemagglutinating and proteolytic activities.

Bacillus↗
PubMedDate not supplied

[Role of the surface and extracellular substances of the phytopathogenic bacterium Xanthomonas campestris in its interactions with cabbage plants].

Changes in some physiological and biochemical characteristics of cabbage (cv. Slava) seedling roots in response to inoculation with the phytopathogen Xanthomonas campestris and its surface and extracellular substances were evaluated. Seven days after the inoculation, the growth of the roots was slightly suppressed and they contained increased amounts of peroxidase. The effect of the lipopolysaccharides stripped from the cell surface or isolated from the culture liquid of X. campestris was similar to that of the whole cells of the phytopathogen. The bacterial lectin isolated from the cell surface material did not induce any defense response in cabbage plants but, presumably, could play a role in the contact interactions between bacteria and plants.

Brassica↗
PubMedDate not supplied

[Participation of azospirillium polysaccharides in interaction with wheat root surface].

The present study was undertaken to comparatively investigate the attachment capacities of Azospirillum brasilense Sp245 and its lipopolysaccharide-defective Omegon-Km mutants KM018 and KM252, as well as their activities with respect to the alteration of the morphology of wheat seedling root hairs. The adsorption dynamics of the parent Sp245 and mutant KM252 strains of azospirilla on the seedling roots of the soft spring wheat cv. Saratovskaya 29 were similar; however, the attachment capacity of the mutant KM252 was lower than that of the parent strain throughout the incubation period (15 min to 48 h). The mutation led to a considerable decrease in the hydrophobicity of the Azospirillum cell surface. The lipopolysaccharides extracted from the outer membrane of A. brasilense Sp245 and mutant cells with hot phenol and purified by chromatographic methods were found to induce the deformation of the wheat seedling root hairs, the lipopolysaccharide of the parent strain being the most active in this respect. The role of the carbohydrate moiety of lipopolysaccharides in the interaction of Azospirillum cells with plants is discussed.

Azospirillum brasilense↗