FIG 2.

AmpC induction by cell wall inhibitors. The graph shows the induction of the C. freundii ampC reporter plasmid in the presence of cell wall-active compounds. Expression of ampC was detected upon cleavage of the colorimetric β-lactam analog nitrocefin, as measured by the A₄₉₀. Induction was calculated as the A₄₉₀/OD₆₀₀ ratio to correct for cell density. The LpxC inhibitor was CHIR-90 (29). The effects of compounds 1 and 2 on the reporter are also shown.