FIG. 6.
Expression of dsrA from PBAD. A. Strains of E. coli or S. enterica with an rpoS-lac [pr] fusion in the bacterial chromosome, deleted for dsrA, and also carrying a plasmid PBAD-dsrA construct from the species indicated, were induced with 0.02% arabinose and grown overnight to stationary phase in LB-Amp medium at 32°C. Activity of β-galactosidase is plotted for each strain, normalized to the expression seen with a vector control. B and C. Northern analysis of DsrA accumulation in E. coli and S. enterica strains carrying plasmids expressing either S. enterica dsrA (B) or E. coli dsrA (C) under the control of the PBAD promoter. Strains carrying the appropriate empty vector were used as controls. Culture conditions, RNA purification, and Northern blotting were carried out as described in Materials and Methods. Strains were TE9416, TE9418, TE9419, TE9422, TE9424, TE9425, TE9426, TE9427, TE9428, TE9429, TE9430, and TE9431.