FIG. 9.

Curli expression during pellicle formation. Bacteria were grown in LBNS broth for 3 days at 26°C. (A) Western blots of the wt (lanes 1 and 2), the A59 crl⁺ strain (lanes 3 and 4), the C24 csgFG⁺ strain (lanes 5 and 6), and the A59 crl mutant (lanes 7 and 8). Since the C24 csgFG mutant did not form a pellicle, planktonic bacteria from the liquid culture and aggregates at the bottom were collected for Western analysis (lanes 11 and 12). A mixture of pellicle, planktonic cells, and aggregates of the wt strain was used as the control (lanes 9 and 10). Samples were pretreated with (+) or without (−) HFIP before being loaded onto an SDS-polyacrylamide gel and probed with CsgA antibody. (B) Transmission electron microscopy of the wt, A59 crl⁺, C24 csgFG⁺, and A59 crl strains collected from pellicles. Scale bars are equal to 500 nm.