Genomic organization of the luxS region in Salmonella Typhimurium. Coding sequences are depicted with arrows. Mutated regions in different luxS mutants are indicated. The figure is drawn to scale. a The putative -10 and -35 regions of MicA as reported by Udekwu et al. . b 5' end of the luxS fragment with own promoter for the construction of the complementation construct pCMPG5664 as reported by De Keersmaecker et al. .