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Biomedical subjects

V V Ignatov

Publications and source records attributed to V V Ignatov.

65 records · Page 4Linked to original sources
PubMedDate not supplied

[A bioelectrochemical study of a suspension of Escherichia coli cells metabolizing glucose and lactose].

The metabolism of glucose and lactose in E. coli K-12 cells has been studied using a bioelectrochemical (BEC) approach. The magnitude and the duration of the response of a BEC anode were found to be functions of the composition of nutrient media and the concentration of bacterial cells. The amount of electricity that is generated enzymatically during the metabolism of a particular substrate depends on the activity of the relevant enzymes. This suggests that the BEC approach can be used for evaluating the activity of particular enzyme systems.

Biosensing Techniques↗
PubMedDate not supplied

[Chemical composition and immunochemical characteristics of the lipopolysaccharide of nitrogen-fixing rhizobacterium Azospirillum brasilense CD].

The chemical composition of the lipopolysaccharide of the associative diazotrophic rhizobacterium Azospirillum brasilense Cd has been studied. Among the main components of the hydrophobic part of the lipopolysaccharide, we identified 3-hydroxytetradecanoic, hexadecenoic, 3-hydroxyhexadecanoic, hexadecanoic, octadecenoic, and nanodecanoic fatty acids; the carbohydrate part contained rhamnose, galactose, and mannose. Polyclonal antibodies against the preparation under study were raised in rabbits. Serological relations between A. brasilense Cd and other strains of Azospirillum spp. were studied using double radial immunodiffusion and enzyme-linked immunosorbent assay.

Azospirillum brasilense↗
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

[Fluorescent probe study of staphylococcal cell wall charges].

The effect of pH and MgCl2 concentration on the fluorescence of 1-anilinonaphthalene-8-sulfonate (ANS), an anion probe, was studied in suspensions of Staphylococcus aureus. The maximum of ANS fluorescence shifted towards the short wavelength region of the spectrum and its intensity increased when the cells were incubated in the medium with low pH and high ionic strength. The results are discussed in terms of electrostatic interactions between the anions of the probe and the negative space charge of the cell wall.

Anilino Naphthalenesulfonates↗
PubMedDate not supplied

[Properties of polysaccharide complexes produced by Azospirillum brasilense and polysaccharides isolated from these complexes].

Azospirillum brasilense strains Sp7, Sp7 (S-form), Sp107, Sp245, Sp246, S17, and 15 when cultivated in a liquid synthetic malate medium up to the end of the logarithmic phase of growth were shown to produce at least two complex polysaccharide-containing components. The components were arbitrarily called lipopolysaccharide-protein complex (LPPC) and polysaccharide-lipid complex (PSLC). The LPPCs and PSLCs from the strains Sp7, Sp107, Sp245, Sp246, and S17 were shown to interact with a wheat germ agglutinin (WGA). From PSLCs, acidic polysaccharides (PS) were isolated and their specific rotation, molecular masses, affinity for WGA, and monosaccharide composition were determined. The PSs of all strains contained rhamnose, galacturonic acid, and galactose (except the strain Sp246), and glucosamine (except the strain Sp7 (S-form)), while the PSs of the strains Sp7 and S17 also contained fucose and mannose, respectively. It is suggested that LPPCs and PSLCs may be involved in the process of interaction of azospirilla with wheat root surfaces, and that PSsare probably active parts of the LPPCs and PSLCs. The ability of LPPCs and PSs to interact with Congo red in aqueous solutions was investigated.

Azospirillum brasilense↗
PubMedDate not supplied

[Cell wall of pigmentless variants of Staphylococcus aureus].

Physico-chemical properties and chemical composition of the cell wall of pigmentless variants B-3 and B-6 differ from those of the parent strain of Staphylococcus aureus 209-P. As to morphology, the wall is more thick and loose. The mutants differ also by the phagotype, the ability for sorption of acridine orange, and the rate of sedimentation of cell suspensions. The properties of teichoic acids and the content of peptides in peptidoglycan change in the cell wall of the mutants.

Cell Wall↗