[The role of antioxidant systems in response of bacteria Escherichia coli to heat shock].
Shifting the temperature from 30 to 45 degrees C in an aerobic Escherichia coli culture inhibited the expression of the antioxidant genes katG, katE, sodA, and gor. The expression was evaluated by measuring beta-galactosidase activity in E. coli strains that contained fusions of the antioxidant gene promoters with the lacZ operon. Heat shock inhibited catalase and glutathione reductase, lowered the intracellular level of glutathione, and increased its extracellular level. It also suppressed the growth of mutants deficient in the katG-encoded catalase HPI, whereas the sensitivity of the wild-type and sodA sodB mutant cells to heat shock was almost the same. In the E. coli culture adapted to growth at 42 degrees C, the content of both intracellular and extracellular glutathione was two times higher than in the culture grown at 30 degrees C. The temperature-adapted cells grown aerobically at 42 degrees C showed an increased ability to express the fused katG-lacZ genes.
Smirnova
G V
GV
Institute of Ecology and Genetics of Microorganisms, Ural Division, Russian Academy of Sciences, ul. Lenina 11, Perm, 614600 Russia.
Zakirova
O N
ON
Oktiabr'skiĭ
O N
ON
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D017930:Genes, Reporter; D005978:Glutathione / Q000235:genetics / Q000378:metabolism; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D007763:Lac Operon; D009154:Mutation; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D010544:Peroxidases; C102664:hydroperoxidase II; D002374:Catalase; C076136:catalase HPI; C095500:SodA protein, Bacteria; C087504:SodB protein, Bacteria; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D001616:beta-Galactosidase; D005978:Glutathione
Rol' antioksidantnykh sistem v otklike bakteriĭ Escherichia coil na teplovoĭ shok.