Figure 3.

Viability of wild type and zwf-knock-out mutant E. coli JM101 in paraquat-containing media. Exponentially growing cultures were treated with the indicated concentrations of paraquat for 45 min and then plated on LB medium for 20 to 36 h. Colony survival units plotted are expressed as a percentage of viable counts in cultures not exposed to paraquat. The experiment was repeated three times.