FIG. 2.

Comparison of CyaR expression under different conditions. (A) β-Galactosidase assays of strain CV8000, which contains a lacZ transcriptional fusion to the cyaR promoter, grown at 37°C in LB liquid medium with or without glucose. β-Galactosidase assays were performed using samples taken from the cultures during log phase, late log phase, or stationary phase. (B) β-Galactosidase assays of strain CV8000 (WT) or derivatives of strain CV8000 harboring a cya deletion (NRD351) or a crp deletion (NRD352) grown at 37°C in LB liquid medium. β-Galactosidase assays were performed using samples taken from cultures of each strain during log phase or late log phase. The data in panels A and B are averages of three independent experiments. (C) Northern blot analysis of total RNA from a culture of strain NRD359/pNRD405 grown in LB liquid medium containing ampicillin and IPTG (control) (lane 1), from log-phase and late-log-phase cultures of wild-type strain MG1655 (WT) (lanes 3 and 4, respectively), or from log-phase and late-log-phase cultures of the Δcrp strain NRD345 (lanes 5 and 6, respectively) grown in LB liquid medium at 37°C. Five times more RNA was loaded in lanes 5 and 6 (Δcrp) than in lanes 3 and 4 (wild type). The ryeEprobe1 was used to detect RNA encoding cyaR.