
Competition assays. Strains SQ2518/p19Cr (wt) and SQ2518/p19Crmut (mut) were grown in competition with a reference strain, SQ2518lacZ/p19Cr, over 10 generations of growth in LB medium at 37°C. The ratios of the strains after competitive growth were normalized to the ratio of the strains prior to competitive growth. Standard deviations, as indicated, are derived from 10 experiments for each set of competing strains. P < 0.05 using the matched-pair test.










