Fig. 2. An ompL null mutation does not restore the motility defect of a dsbA null mutant. Bacterial motility was monitored after 8 h of incubation at 37°C on soft agar plates. A typical set of results showing the radial growth of the dsbA and ompL single mutants and of the dsbA ompL double mutant compared with the parental strain MG1655 (WT) is presented. The ompL allele shown here is the ompL::mini-Tn10Kan^R allele (Dartigalongue et al., 2000).