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Your search keyword '"Muzyka, Nadezda"' showing total 23 results
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23 results on '"Muzyka, Nadezda"'

1. Changes in Physiological Parameters of Escherichia coli During Antibiotic-Induced Stress Response

Author

Tyulenev, Aleksey V., Smirnova, Galina V., Muzyka, Nadezda G., Samoilova, Zoya Y., Oktyabrsky, Oleg N., Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Isaeva, Ekaterina, editor, and Rocha, Álvaro, editor

Published
2023
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14. Influence of Growth Medium Composition on Physiological Responses of Escherichia coli to the Action of Chloramphenicol and Ciprofloxacin.

Author

Smirnova, Galina, Tyulenev, Aleksey, Muzyka, Nadezda, Ushakov, Vadim, Samoilova, Zoya, and Oktyabrsky, Oleg

Subjects
CHLORAMPHENICOL, ESCHERICHIA coli, BACTERICIDAL action, ELECTROCHEMICAL sensors, MEMBRANE potential, CIPROFLOXACIN, HYDROGEN sulfide
Abstract

The ability of hydrogen sulfide (H2S) to protect bacteria from bactericidal antibiotics has previously been described. The main source of H2S is the desulfurization of cysteine, which is either synthesized by cells from sulfate or transported from the medium, depending on its composition. Applying electrochemical sensors and a complex of biochemical and microbiological methods, changes in growth, respiration, membrane potential, SOS response, H2S production and bacterial survival under the action of bactericidal ciprofloxacin and bacteriostatic chloramphenicol in commonly used media were studied. Chloramphenicol caused a sharp inhibition of metabolism in all studied media. The physiological response of bacteria to ciprofloxacin strongly depended on its dose. In rich LB medium, cells retained metabolic activity at higher concentrations of ciprofloxacin than in minimal M9 medium. This decreased number of surviving cells (CFU) by 2–3 orders of magnitude in LB compared to M9 medium, and shifted optimal bactericidal concentration (OBC) from 0.3 µg/mL in M9 to 3 µg/mL in LB. Both drugs induced transient production of H2S in M9 medium. In media containing cystine, H2S was produced independently of antibiotics. Thus, medium composition significantly modifies physiological response of E. coli to bactericidal antibiotic, which should be taken into account when interpreting data and developing drugs. [ABSTRACT FROM AUTHOR]

Published
2023
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23. The role of antioxidant enzymes in response of Escherichia colito osmotic upshift

Author

Smirnova, Galina V., Muzyka, Nadezda G., and Oktyabrsky, Oleg N.

Abstract

Aerobic growth of Escherichia coli sodAsodBand katEmutants lacking cytosolic superoxide dismutases and catalase hydroperoxidase II was inhibited by osmotic upshift to a greater extent than of their wild‐type parent strains. The furmutation leading to an intracellular overload of iron also increased sensitivity of growing E. colicells to osmotic upshift. Using lacZfusions, it was shown that expression of antioxidant genes soxSand katEwas stimulated by an increase in osmolarity. These data suggest that in aerobically growing E. colicells, moderate osmotic upshift causes activation of certain antioxidant systems.

Published
2000
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