Transformation of a C. jejuni flaA flaB strain with a recombinant plasmid harboring either flaA or flaB restores Cia secretion. C. jejuni cells were precultured on Mueller-Hinton plates supplemented with deoxycholate and labeled in minimal essential medium in the presence of FBS. Lanes: 1, C. jejuni 81116 wild-type strain; 2, C. jejuni 81116 flaA flaB (GRK7) mutant harboring pMEK3502 (flaA+); 3, C. jejuni 81116 flaA flaB (GRK7) mutant; 4, C. jejuni 81116 flaA flaB (GRK7) mutant harboring pMEK3503 (flaB+); 5, C. jejuni 81116 flaA (flaB+) (GRK17) mutant. The positions of molecular mass standards are indicated on the left (in kilodaltons).