FIG. 3.

Assays of pilus function for mutants defective in pilus retraction. (A) Subsurface TM assays were performed as described in Fig. 1. The bar represents 1 cm. (B) Graph depicting average twitching zone diameters for the indicated strains. Shown are the means ± the SD (n = 5) The residual zone observed in the ΔpilT and ΔpilB strains represents colony growth and is similar to that of the ΔpilA strain. (C) Surface structures (SS) and intracellular (WC) preparations of the indicated strains were immunoblotted with a polyclonal antibody to PilA (α-pilA) or to FliC (α-FliC), as described in Fig. 2.