D. Immunohistochemical analysis of FadA in log and stationary phases. Fn12230 (Fn), fadA-deletion mutant US1 (∆fadA) and spontaneous mutant lam in log and stationary phase were fixed before being placed onto glass slides and stained by mAb 7H7 at 1:800 dilution, followed by incubation of HRP-conjugated anti-mouse IgG and developed by DAB. The large FadA aggregates are detected specifically in wild-type Fn 12230 in the stationary but not in log phase. FadA was detected on lam, but without secreted aggregates. No FadA was detected in US1. The imagines were taken using 40X objective. Scale bar equals 20 μm. 