Evidence that bacteriophage ? Lysogens may induce in response to the proton motive force uncoupler cccp

Abstract

We describe a genetic ß-galactoside reporter system using a disk diffusion assay on MacConkey Lactose agar petri plates to monitor maintenance of the bacteriophage ? prophage state and viral induction in Escherichia coli K-12. Evidence is presented that the phage ? major lytic promoters, pL and pR, are activated when cells containing the reporters are exposed to the energy poison carbonyl cyanide m-chlorophenyl hydrazine, CCCP. This uncoupler of oxidative phosphorylation inhibits ATP synthesis by collapsing the proton motive force. Expression of the ? lytic promoters in response to CCCP requires host RecA function and an autocleavable CI repressor, as does SOS induction of the ? prophage that occurs by a DNA damage-dependent pathway. ? Cro function is required for CCCP-mediated activation of the ? lytic promoters. CCCP does not induce an sfi-lacZ SOS reporter.