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Biomedical subjects

A S Gordienko

Publications and source records attributed to A S Gordienko.

11 recordsLinked to original sources
PubMedDate not supplied

[Protective action of electromagnetic radiation (40.68 MHz) on Saccharomyces cerevisiae UCM Y-517].

Electromagnetic radiation (EMR) (40.68 MHz, 15 and 30 W) has been studied for its effect on survivability of cells of Saccharomyces cerevisiae UCM Y-517 under the extremal influence of the environment factors (pH, freezing-thawing, nistatin (1.0 microg/ml)). It is shown that even short-term irradiation of the yeast suspension (during 5 min) takes protective effect under the conditions of stress factors, displayed in the increase of the number of live intact cells. It was established by cytochemical methods that 50-70 % of cells were characterized as damaged and dead in the control samples after yeast exposition under the stress conditions. Such an effect was not observed in the samples of preliminary irradiated cells. The pool of extracellular nucleotides was shown to decrease as a result of the yeast cells irradiation; one could also observe the decrease of these cells ability to acidity the culture medium. The increase of activity of intracellular enzymes of dehydrogenase complex was noted as well. Stability of electrostatic characteristics of the cell surface (zeta-potential) and catalase activity under the effect of EMR of radio-frequency range has been demonstrated. The found effect of protective action of EMR of the above frequency is of nonspecific character, which allows its mechanism universality to be supposed.

Antifungal Agents↗
PubMedDate not supplied

[Interaction of some Pseudomonas genus representatives with high-dispersed silicon dioxide particles].

The effect of increase of a negative charge in the cell during contact interaction with silicon dioxide particles similar to those previously obtained for methanotrophic bacteria was observed in pseudomonads. The microelectrophoretic method application has allowed to find a capsule and consists of uncharged components in Pseudomonas batumici bacterial cells; the capsule thickness was determined by conditions of microorganisms cultivation. The effect of increase of a negative charge took place for the cells grown on the Kozer medium where they formed a capsule of smaller dimensions. It is supposed that the sorption of silicon dioxide particles on the bacterial surface initiates the conformational changes of porins. As a result, the quantity of the charged groups increases and thickness of the surface layer in which these groups are located also augments.

Bacterial Adhesion↗
PubMedDate not supplied

[Chemotaxis and growth of Bradyrhizobium japonicum in the presence of fine-dispersed silica].

The chemotactic properties of the soybean nodule bacterium Bradyrhizobium japonicum were studied in the presence of synthetic fine-dispersed materials. It was shown that fine-dispersed silica (FDS) and its variety modified with aluminum oxide (MFDS) reduce bacterial chemotaxis to glucose. In addition, FDS increases the irregular motility of B. japonicum, and MFDS decreases it. This is in agreement with the effect of the materials on the rate of nodule bacterium growth.

Aluminum Oxide↗
PubMedDate not supplied

[Effect of cultivation conditions of Bacillus subtilis IMV B-7023 on surface properties of cells].

It has been established that the cells of Bacillus subtilis IMV B-7023 grown on the medium where peptone or calcium glycerophosphate served as the only source of carbon and energy have similar acid type of the surface and are characterized by a high negative charge even at low values of pH of the dispersion medium. This may be determined by the presence of phosphate groups, teichoic acids being their carriers in Gram-positive bacteria. Glucose addition to peptone or glycerophosphate leads to the change of the bacteria surface type, i.e., at low values of pH the cells have total positive charge, that allows to suppose availability of protein nature components in the surface layers of the cell wall. Bacteria grown in these conditions are also characterized by the higher degree of adhesion to inert carrier (glass).

Bacillus subtilis↗
PubMedDate not supplied

[Hydrophilic-hydrophobic properties of microorganisms under various culturing conditions].

The index of hydrophobicity and the hydrophilic-hydrophobic properties of seven microbial cultures were determined by studying their adhesion to n-hexadecane. The index of hydrophobicity was shown to be a stable characteristic of a culture grown in media with different carbon sources. As was found for Escherichia coli K-12 and Acinetobacter calcoaceticus K-9 whose hydrophobicity indicates were quite different, the character of cell hydration was virtually independent of the growth phase and did not change upon either submerged or superficial cultivation.

Acinetobacter↗
PubMedDate not supplied

[Sorption of microorganisms by fiber materials].

Candida guilliermondii and Escherichia coli cells were adsorbed on glass and basalt fibres with a similar specific surface, but with a different charge. The quantity of adsorbed microorganisms did not depend on the type and charge of a fibre surface. However, cells were adsorbed faster and more firmly on positively charged and uncharged fibres than on negatively charged fibres.

Adsorption↗
PubMedDate not supplied

[Microelectrophoresis apparatus].

The described installation for microelectrophoresis is distinguished by the open-type electrode cameras. Platinum electrodes now employed considerably simplify its construction and operation. The design of this installation allows easy replacement of damaged blocks. It is recommended for studying the electrokinetic properties of microorganisms, blood cells and other dispersed particles.

Electrophoresis↗