To investigate whether z66 is regulated by FliA like other biphasic S. fliA mutants were affected by the osmotic environment , an ompR mutant was also prepared .
These results indicate that the fliA operon itself is under the positive control of FliA .
In this investigation , we observed that ( i ) the in-vitro generation times of flgM mutant and wild-type strains of S. typhimurium were indistinguishable , as were the amounts of flagellin produced by the strains ; ( ii ) the 50 % lethal doses of fliA mutant and wild-type strains of S. typhimurium were similar in orally infected mice ; and ( iii ) inactivation of the FliA-regulated flagellin gene fliC in an flgM S. typhimurium mutant resulted in a virulent phenotype .