FIG 6.

Ectopic csrT expression inhibits motility via a conserved mechanism. (A) Western analysis of flagellin protein was performed on PE-phase cultures of L. pneumophila strain Lp02 carrying pcsrA (MB1389) or pcsrT (MB1383), induced (+) or not induced (−) with IPTG as indicated. Lp02 WT with no vector (MB110) was used as a positive control, and a flaA mutant (MB1390) was used as a negative control. The percentage of bacteria that were motile was judged by phase microscopy of wet mounts. Shown are results of one experiment that is representative of at least three others. (B to E) B. subtilis swarming motility was assessed on swarm agar plates every 30 min for WT (filled circles; strain 3610) and fliW sow3 mutants, which are insensitive to B. subtilis CsrA repression mutant (open circles; DS6530) with no vector (B), induced expression of B. subtilis csrA (DS4940 and DK1469) (C), induced expression of L. pneumophila csrT (DK677 and DK1471) (D), or induced expression of L. pneumophila csrA (DK675 and DK1470) (E). Plots represent the means of triplicate plates from one experiment.