[The status and the role of glutathione under disturbed ionic balance and pH homeostasis in Escherichia coli].
The study of glutathione status in aerobically grown Escherichia coli cultures showed that the total intracellular glutathione (GSHin + GSSGin) level falls by 63% in response to a rapid downshift in the extracellular pH from 6.5 to 5.5. The incubation of E. coli cells in the presence of 50 mM acetate or 10 micrograms/ml gramicidin S decreased the total intracellular glutathione level by 50 and 25%, respectively. The fall in the total intracellular glutathione level was accompanied by a significant decrease in the (GSHin:GSSGin) ratio. The most profound effect on the extracellular glutathione level was exerted by gramicidin S, which augmented the total glutathione level by 1.8 times and the (GSHout:GSSGout) ratio by 2.1 times. The gramicidin S treatment and acetate stress inhibited the growth of mutant E. coli cells defective in glutathione synthesis 5 and 2 times more severely than the growth of the parent cells. The pH downshift and the exposure of E. coli cells to gramicidin S and 50 mM acetate enhanced the expression of the sodA gene coding for superoxide dismutase SodA.
Smirnova
G V
GV
Institute of Ecology and Genetics of Microorganisms, Ural Division, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081 Russia. smirnova@ecology.psu.ru
Torchova
O A
OA
Oktiabr'skiĭ
O N
ON
D000085:Acetates; D000332:Aerobiosis; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005978:Glutathione / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D006096:Gramicidin; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
D000085:Acetates; D006096:Gramicidin; D013482:Superoxide Dismutase; D005978:Glutathione