Figure 4

Expression of rgsA - lacZ and hcnA'-'lacZ fusions. a. β-Galactosidase activities of an rgsA _PAO1 -lacZ transcriptional fusion (pME7235) were determined in the P. aeruginosa wild-type PAO1 (squares) and in the gacA mutant PAO6281 (triangles). b. β-Galactosidase activities of an rgsA _CHA0 -lacZ transcriptional fusion (pME7234) were determined in the P. fluorescens wild-type CHA0 (squares) and in the gacA mutant CHA89 (triangles). c. β-Galactosidase activities of a chromosomal hcnA'-'lacZ translational fusion were determined in a P. fluorescens wild-type context (CHA207) carrying the empty pME6032 vector (filled squares) or the rgsA overexpressing plasmid pME7236 (open squares), and in the rsmXYZ triple mutant (CHA1145) carrying pME6032 (filled diamonds) or pME7236 (open diamonds). 1 mM IPTG was added when the cultures were inoculated. Each value in a, b and c is the average from three different cultures ± standard deviation. d. Verification of the overexpression of RgsA sRNA by Northern blot. Total RNA was purified from cultures of P. fluorescens CHA0 (wild type) and CHA815 (rpoS mutant) grown to stationary phase, carrying the empty pME6032 vector (-) or the rgsA overexpressing plasmid pME7236 (+).