[Changes in the redox potential and the number of accessible sulfhydryl groups in Escherichia coli and Bacillus subtilis cultures during transient processes].

It was shown that changes in the redox potential can be due to the influence of compounds which alter the intracellular pH (acetate or propionate, protonophore carbonyl-cyanide-m-chlorophenyl hydrazone, permeate cation TPP+). A correlation was found between the redox potential changes and the number of SH-groups in the medium and on cell surface. It was shown also that the previously reported redox potential shifts during the transition of E. coli and B. subtilis cultures to the stationary phase under glucose or ammonium exhaustion are due to the increase in the number of SH-groups in the medium and on cell surface. A hypothesis is put forward, according to which the changes in intracellular pH play a trigger role, whereas those in the thiol: disulfide ratio inside and outside the cells are thought to amplify regulatory signals.