FIG. 4.

Regulation of zmpB by the cepIR and cciIR quorum-sensing genes. Plasmid pBS9 containing a zmpB::luxCDABE fusion was introduced into K56-2 quorum-sensing mutants. Cultures were grown for 20 h, and luminescence in counts per second (CPS) and turbidity at an absorbance of 600 nm were measured using a Wallac Victor² 1420 multilabel counter. Values shown are the mean relative CPS (±standard deviation) for triplicate cultures and are representative of three independent experiments. *, significantly different from result for K56-2 (P < 0.05 by analysis of variance).