FIG. 6.
Analysis of flaA expression and FlaA secretion mediated by the FEA. (A) Arylsulfatase assays for analysis of expression of flaA::astA in the C. jejuni 81-176 Smr wild-type strain or strains with a secretion-impaired FEA. The results are the results of a typical assay in which each strain was tested in triplicate. The values for each strain are the average arylsulfatase activity ± standard deviation relative to the level of expression of each transcriptional fusion in wild-type strain 81-176 Smr ΔastA, which was defined as 100 arylsulfatase units. For expression of flaA::astA, the strains used included (from left to right) wild-type strain DRH655 (WT), DRH1070, SNJ365, SNJ427, SNJ1033, SNJ1034, SNJ1038, and SNJ1042. The type of mutation in each strain is indicated below the graph. (B) Immunoblot analysis of FlaA production in WCLs and secretion to the outer membrane of wild-type and FEA mutant strains. WCL and outer membrane (OM) fractions were isolated from wild-type and mutant strains of C. jejuni. Anti-FlaA LL-1 antiserum was used to detect the FlaA proteins (42). The strains used included (from left to right) wild-type strain DRH212 (WT), DRH724, DRH655, SNJ471, SNJ464, SNJ428, SNJ475, SNJ438, and DRH2257.