Figure 5.

Expression of gacA (A), rsmA (B), rpoS (C), and relA (D) in logarithmic phase wild-type PAO1 and the ΔrpoN, ΔrpoS, ΔrpoNΔrpoS, and ΔrpoN/rpoN⁺ mutants grown in the LB medium in the presence of 32 μg/ml tobramycin. The transcript levels were measured by qRT-PCR, were normalized to omlA expression, and are expressed relative to wild-type PAO1 at time = 0 h. The time points at which the cells were sampled for transcriptional analysis were t = 0 h and t = 3 h after the addition of tobramycin, as indicated. All results are the average of at least three independent experiments, and the error bars represent SDs. P ≤ 0.05 (^*), ≤0.01 (^**).