FIG 2.
(A) Genetic map of the Pshp1518-lacZ reporter and β-galactosidase expression in the wild-type strain and Δrgg mutants. The reporter was constructed by homologous recombination of pHDY06 plasmid (tetM: tetracycline resistant) into the bgaA locus of the parental strain CP2000 (−LacZ). (B) Colony color phenotype of wild-type (Pshp1518-lacZ) and Δrgg reporter strains after 40 h of growth in CDM (glucose) sandwich agar supplemented with 400 μg/mL X-Gal; −LacZ: the parental strain without the lacZ gene; +LacZ, a LacZ reporter strain where lacZ expression is driven by a constitutive kanamycin promoter; Δrgg, knockouts of a corresponding rgg regulator. (C) Synthetic C12 activates Rgg/SHP1518 quorum sensing in a dose-dependent manner in CDM. Gradient amounts of C12 peptides were incubated with wild-type and Δrgg1518 strains for 30 min. A Miller assay was performed to monitor LacZ expression of the three strains (recorded as UV420 absorbance). Data represent the average of three technical replicates.