Northern blot revealing RsmZ RNA. Total RNA (4 μg) from P. aeruginosa PAO1 and PAO6354 was electrophoresed in a urea-8% acrylamide-0.4% bisacrylamide gel and hybridized with an rsmZ digoxigenin-labeled probe (see Materials and Methods). (A) Lane 1, PAO1; lane 2, PAO6354 (ΔrsmZ). (B) Lane 1, PAO1/pME6000 vector control; lane 2, PAO1/pME3337.1 (rsmZ++). nt, nucleotides.