Figure 4

Nitrosoguanidine mutagenesis identifies additional regulators of sigS expression. (A) The SH1000 sigS-lacZ fusion strain was subjected to MNNG mutagenesis. Two resulting clones were selected for further analysis during growth in TSB at 37°C. HKM15 and HKM16 were grown along side the parent strain, SH1000, with samples collected at 5 hours. β-Galactosidase activity was measured using 4-MUG as a substrate to determine sigS expression levels. Assays were performed on duplicate samples and the values averaged. The results presented are from three independent experiments. Error bars are shown as ± SEM. (B) qPCR for sigS expression was performed on SH1000 strains containing a mutation in either lacR or kdpD. Error bars are shown as ± SEM. Significance was determined using a Student t test; *indicates a p value of <0.05.