Figure 5
From: Pseudomonas aeruginosa β-lactamase induction requires two permeases, AmpG and AmpP
Relative β-lactamase activity in PAO ampP and PAO ampG mutants. Assays were performed on the parental PAO1, and the mutants, PAOampP and PAOampG in the presence of benzyl-penicillin at a concentration gradient of 0 to 125 μg/ml. Cultures at OD600 of 0.6-0.8 were induced for three hours before harvesting. Assays were performed on sonicated lysate using nitrocefin as a chromogenic substrate. The β-lactamase activity of PAO1 at 100 μg/ml of benzyl-penicillin was taken as 100%. Each value is the mean of at least three independent experiments. The asterisk refers to p-values of < 0.05 with respect to PAO1, which were calculated using the two-tailed Student's t-test.