| Autor: |
Bryan, L. E., Kwan, Sallene |
| Zdroj: |
Journal of Antimicrobial Chemotherapy (JAC); 1981, Vol. 8 Issue suppl_D, p1-8, 8p |
| Abstrakt: |
An Escherichia coli strain without respiratory quinones (Q−) did not transport aminoglycosides whereas transport occurred in that strain when quinone sufficient or in an isogenic quinone-sufficient transductant. Phenazine methosulphate and ascorbate stimulated gentamicin uptake in Q− bacteria including Clostridium perfringens. All of this uptake was retained under anaerobic conditions or in the presence of 1 mM KCN. Phenazine methosulphate and ascorbate also increased gentamicin uptake in quinone-sufficient bacteria and most of this was resistant to inhibition by anaerobiosis or 1 mM KCN. Gentamicin uptake was measured at five values of proton motive force utilizing varying external K+ concentrations and valinomycin-treated Bacillus subtilis. Preliminary results showed that gentamicin uptake increased with membrane potential (Δψ). A minimal value of Δψ appeared necessary before gentamicin uptake was initiated. A preliminary value of Δψ for Cl. perfringens was determined for growing cells at pH 6.2 and was 137 mV. We conclude that a quinone oxidation-reduction cycle is needed to transport aminoglycosides. Resistance of anaerobic bacteria or facultative bacteria grown anaerobically results from an absence or low activity of the quinone cycle and/or a low or absent membrane potential (Δψ). [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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