FIG 5.

Expression of the PA5530-lacZ reporter is dependent on the mifR gene. Expression of the PA5530-lacZ reporter was reduced by >95% in a ΔmifR mutant of P. aeruginosa PAO1 compared to that observed in wild-type cells. Cells harboring a dctD transposon insertion (dctD::Tn) displayed wild-type levels of LacZ activity. However, deletion of the mifR gene in dctD::Tn cells eliminated the expression of PA5530-lacZ. These findings suggest that MifR regulates C₅-dicarboxylate transport, whereas DctD is involved in the transport of C₄-dicarboxylates. Note that all strains were grown in nutrient broth no. 2 (Oxoid) to an OD₆₀₀ of 0.3 and then induced with 20 mM α-KG. LacZ activity was measured at 90 min postinduction. Data points represent mean values ± SD (n = 3). Analysis of variance was performed by using Dunnett's post hoc test (α-value of 0.05) to identify significant changes (P < 0.0001), which are marked (asterisks).