FIG. 1.

Analysis of A. pleuropneumoniae AP76 wt (lanes 1), ΔureC (lanes 2), ΔexbB (lanes 3), and ΔureC ΔexbB (lanes 4) strains. Lanes M, size markers; lanes N, negative controls for PCR. (A) PCR using primers ureC2 and ureX (left) and RE1 and BA7 (right). (B) Southern blot analysis using the ureC gene (left) and the exbB gene (right) as probes. The ureC probe is cut by BstEII and SphI, with BstEII located outside and SphI located within the deletion site. The exbB probe is not cut by EcoRV and PacI, with EcoRV located outside and PacI located within the deletion site. (C) PFGE of ApaI-, AscI-, and NotI-digested DNA showing that no gross rearrangements have occurred. (D) Coomassie blue-stained gel (left) and Western blots developed with serum directed against the TbpB protein (middle) and the ExbB protein (right) of whole cell lysates obtained from cultures grown under iron-restricted conditions, showing that TbpB expression in the exbB mutants (ΔexbB and ΔureC ΔexbB) is unaffected. The open arrowhead indicates the position of the TbpB protein; the solid arrowhead indicates the position of the ExbB protein.