Effects of the B. cenocepacia cblS, cblT, and cblR mutations on cable pilus expression. Transmission electron micrographs of wild-type strain BC7 (A), the cblS null strain CM543 (B), the cblS null strain transcomplemented with pVN3 (C), the cblT null strain CM506 (D), the cblR null strain CM434 (E), and the cblR null strain transcomplemented with pMT66 (F) are shown. Bars = 0.5 μm.