FIG. 6.

CcpA mediates carbon catabolite repression of C. perfringens gliding motility. (A) Gliding motility phenotypes of the CcpA-proficient (ccpA⁺) C. perfringens strain 13 and its isogenic CcpA-deficient derivate KO13 (see Materials and Methods for details). A motility assay was performed according to the protocol described in the above figure legends. Top-bottom photographs were taken after 40 h of anaerobic incubation on TYA plates supplemented or not supplemented with glucose (glu) as indicated in the figure. Black dotted circles indicate the initial sizes of the colonies immediately after drop inoculation. (B) Expression of pilT-gusA and pilD-gusA reporter fusions in ccpA⁺ and ccpA cultures of isogenic C. perfringens strains 13 and KO13 grown for 30 h on TY broth in the absence (−) or presence (+) of 1% glucose. β-Glucuronidase activity was calculated as indicated in Fig. 5. For panels A and B, a representative set of results obtained from five independent experiments is shown.