C. jejuni Cia protein secretion requires a functional flagellar apparatus. C. jejuni cells were precultured on Mueller-Hinton plates (lane 1) and Mueller-Hinton plates supplemented with deoxycholate (lanes 2 to 10), and labeled in minimal essential medium in the presence (A) and absence (B) of FBS. Lanes: 1, C. jejuni F38011 (Mueller-Hinton plate); 2, C. jejuni F38011 (Mueller-Hinton deoxycholate plate); 3, C. jejuni F38011 flgB mutant; 4, C. jejuni F38011 flgC mutant; 5, C. jejuni F38011 flgE2 mutant; 6, C. jejuni 81116; 7, C. jejuni 81116 flaA flaB (GRK7) mutant; 8, C. jejuni 81116 flaA (flaB+) (GRK17) mutant; 9, C. jejuni F38011; and 10, C. jejuni F38011 fliD mutant. C. jejuni strains were deemed positive for protein secretion based on the presence of multiple bands in a lane (i.e., panel A, lanes 1, 2, 6, 8, 9, and 10). The positions of molecular mass standards are indicated on the left (in kilodaltons).