Plasmid DNA Supercoiling and Gyrase Activity in <i>Escherichia coli</i> Wild-Type and <i>rpoS</i> Stationary-Phase Cells

Abstract

Stationary-phase cells displayed a distribution of relaxed plasmids and had the ability to recover plasmid supercoiling as soon as nutrients became available. Preexisting gyrase molecules in these cells were responsible for this recovery. Stationary-phase rpoS cells showed a bimodal distribution of plasmids and failed to supercoil plasmids after the addition of nutrients, suggesting that rpoS plays a role in the regulation of plasmid topology during the stationary phase.