Effects of oxygen stress on membrane functions in Escherichia coli: role of HPI catalase

Abstract

Different conditions of oxidative stress were used to study their effects on membrane transport in Escherichia coli K-12. The oxidizing conditions included H2O2, plumbagin (a redox cycling compound that generates superoxide radicals [O2-]), and increased partial pressure of oxygen. Both superoxide radical-generating conditions and H2O2 treatments were found to cause a rapid decrease in proton motive force-dependent and -independent transport. H2O2-pretreated cells had the ability to rapidly recover both proton motive force-dependent and -independent transport. The induction required transcription and translation and was dependent on oxyR+ and katG+, providing evidence that these genes play crucial roles in the rapid recovery of transport. The effects of oxidatively induced loss of proton motive force on cell growth and macromolecular synthesis were also investigated.