FIG 5.

Bacterial survival after UV irradiation. Exponentially growing cultures of S. pneumoniae strains were washed and resuspended in PBS and then challenged with 15 mJ of UV light. Percent survival was quantified by plating bacteria for CFU before and after UV exposure. The uvrA deletion mutant (ΔuvrA) was complemented (ΔuvrA/uvrA) by placing the full gene and native promoter at neutral-gene locus SPD_0022. WT, wild type. Statistical analyses were performed using a nonparametric Mann-Whitney U two-sample rank test (**, P ≤ 0.002; ns, nonsignificant).