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Biomedical subjects

R A Pshenichnov

Publications and source records attributed to R A Pshenichnov.

11 recordsLinked to original sources
PubMed1977

[Certain data on the protoplast ultrastructure].

A study was made of the structure of Bac. subtilis and Listeria monocytogenes protoplasts by the method of scanning electron microscopy. The mechanism of protoplast formation in Gram-positive bacteria and in spheroplasts of Gram-negative bacteria proved to differ. A loss of the rigid form of the cell, round protrusions on cell surface, and an escape of the cytoplasm through the ruptured cell wall in some one place was noted in case of protoplasts. Individual cells can coalesce with one another with the formation of shapeless masses. The formation of small spheroid bodies by budding, and also a division of protoplasts by constriction was described.

Bacillus subtilis↗
PubMedDate not supplied

[Effect of antibacterial factors and cell metabolism biostimulants on bacterial luminescence].

Bioluminescence was used as an index of effects of a series of factors (differing in origin and structure) on cell metabolism. Luminescence of intact cells of Escherichia coli lum+ (a genetically modified strain) was measured on exposure to antibiotics, probiotics, phages, and biostimulators. The sensitivity of E. coli lum+ to antibiotics correlated with the antibiotic-induced luminescence quenching. Bioluminescence-based assessment of the antagonistic activity of the main probiotics (bificoll, bifidobacterin, acylact, colibacterin, and a composite probiotic preparation), each taken at a concentration of 1 dose/ml demonstrated that bacterial luminescence was inhibited by 75-99.9% (exposure time, 30 min). Bioluminescence changes reflected cell damage associated with phage infection. It was shown that bioluminescence stimulation could be used as an index of the effect of immunomodulators (olexin and vermin) on cell metabolism in bacterial cultures.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Changes in the redox potential and pO2 in heat shock to Escherichia coli].

When the growing culture of Escherichia coli was subjected to a temperature above 37 degrees C, the pO2 fell abruptly at 42 degrees C; a reversible decrease in the redox potential (ROP) down to the range of negative values was detected if the growth ceased at 46 degrees C. The drop in the ROP took from 6 to 10 min, with the maximal deviation of 42.5 mV. Such changes in the pO2 and ROP were not caused by a heat shock in the stationary cultures. The change in the ROP was not due to a change in the pH and pO2 of the medium. The authors believe that the effect should be attributed to an elimination of the ionic gradients and the electrochemical gradient delta muH+.

Escherichia coli↗
PubMedDate not supplied

[Changes in the redox potential in Escherichia coli growth cessation].

Escherichia coli strains K-12 and M-17 were grown in batch and continuous cultures, with pulse addition of glucose or a nitrogen source as limiting substrates; the redox potential decreased when the growth ceased. The maximal deviation of the Eh was 150 mV when the strain K-12 ceased to grow. The Eh decreased rapidly for 25 min in the strain K-12 and for about 10--12 min in the strain M-17; then the Eh returned slowly to the initial level. The second phase took about 150 min in the strain K-12 and 40 to 60 min in the strain M-17. No changes in the Eh were found when the culture was grown under the anaerobic conditions.

Culture Media↗