Figure 8.

Induction of rpoS-activating sRNAs and activation of rpoS translation upon acid challenge. Overnight cultures of wild-type and ΔrpoS cells were diluted 1:100 in LB medium and grown for 2 h at 37°C. Cultures were split into two and either maintained or subjected to pH 5.0 (LB buffered by 100 mmol/L MES), then further incubated at 37°C. Aliquots were sampled at specific time intervals for Northern blot analysis (A), and for growth curves (B). Cells containing a rpoS-lacZ translational fusion (SG30013) was also shifted to pH 5.0 and aliquots were sampled for β-galactosidase assay (C).