DNA gyrase reactivation in stationary-phase cells with low levels of polyphosphate, polyP. Cells grown in LB-MOPS media at 37°C. The strains used were BW25113 (wt) and BW25113 Δppk, bearing the reporter plasmid pMS01. To induce the recovery of the DNA SC level in stationary-phase cells, cell cultures were diluted 1:10 in pre-warmed LB-MOPS medium. 1) Exponentially growing cells, 2) 48 hr stationary-phase cells, 3) stationary-phase cells diluted 1:10 in LB-MOPS and incubated for 30 sec, and 4) stationary-phase cells diluted 1:10 in LB-MOPS and incubated for 1 min. Plasmid topoisomers were isolated and separated as described in Figure 1. Similar results were obtained in at least three independent experiments.