The Role of Thiol Redox Systems in the Resistance
of Escherichia coli in the Stationary Phase
The effect of glutathione (gshA), thioredoxin (trxA), and thioredoxin reductase (trxB) mutations on the adaptation of Escherichia coli to prolonged glucose starvation was investigated. The trxB mutation had the worst consequences for the stationary phase cells. These bacteria exhibited decreased survival, increased sensitivity to oxidants, and decreased expression of the katE and sulA genes. As the stationary phase proceeded, the physiological resistance to antibiotics increased in all the strains tested; however, the thiol redox-system mutants were far less able to develop antibiotic resistance than the parent strain cells. During the stationary phase, a considerable shift was observed in the redox status of intra and extracellular glutathione toward the oxidative values. These results indicate that the thiol redox systems play an important role in the adaptation of Escherichia coli to prolonged starvation and antibiotic resistance.