Oxidative Stress Resistance of Escherichia coli Strains Deficient in Glutathione Biosynthesis

G. V. Smirnova, N. G. Muzyka, M. N. Glukhovchenko, T. A. Krasnykh, and O. N. Oktyabrsky^*

Institute of Ecology and Genetics of Microorganisms, Ural Branch of the Russian Academy of Sciences, ul. Goleva 13, Perm, 614081 Russia; fax: (3422) 646-711; E-mail: mike@iegm.perm.su

^* To whom correspondence should be addressed.

Received January 6, 1999; Revision received May 20, 1999

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Sensitivity to various oxidants was determined for Escherichia coli strains JTG10 and 821 deficient in biosynthesis of glutathione (gsh^-) and their common parental strain AB1157 (gsh⁺). The three strains showed identical sensitivity to H₂O₂. E. coli 821 was more resistant than AB1157 and JTG10 to menadione, cumene hydroperoxide, and N-ethylmaleimide. This resistance was not related to the gsh mutation because the other gsh^- mutant and the parental strain showed similar sensitivity to these oxidants. The measured activities of NADPH:menadione diaphorase and glucose-6-phosphate dehydrogenase and the extracellular level of menadione suggested that the enhanced resistance of E. coli 821 to menadione might be due to decreased diaphorase activity, but not to a lowered rate of menadione uptake.

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KEY WORDS: Escherichia coli, oxidants, menadione, glutathione

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