FIG. 1.

Western blot analyses of MucD in P. aeruginosa. (A) Effect of algT polar insertions (algTp) on detection of MucD in strains of PAO and FRD backgrounds. Cultures were grown in L broth to an optical density of 600 nm (OD₆₀₀) of 1.0 and lysed. Proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were probed with rabbit MucD antibodies. Lanes: 1, PAO1 (wild type); 2, PDO-LS586 (algT::aacCIΩ) (29); 3, PDO300 (mucA22; mucoid) (18); 4, PDO350 (ΔmucD::aacCIΩ, mucoid); 5, FRD1 (wild type, mucA22, mucoid) (23); 6, FRD440 (algT::Tn501) (9). MucD protein was detected in all strains except PDO350 (ΔmucD). (B) Effect of a polar insertion in mucB on downstream mucD expression and MucD protein levels. Culturing and immunodetection methods were the same as described for panel A. Samples of PAO1 (10, 20, or 40 μg protein in lanes 1, 2, and 3, respectively) or PDO353 mucB::aacCIΩ (10, 20, or 40 μg protein in lanes 4, 5, and 6, respectively) were compared. Densitometry (performed in triplicate) was used to determine cellular levels of MucD protein.