FIG. 4.

Expression of sinI is dependent on sinR and is induced by expR and Sin AHLs. sinI expression was measured as EGFP fluorescence in strains carrying plasmid pLK64 in the absence (dark gray bars) and presence (light bars) of synthetic oxo-C₁₄-HL (abbreviated as o-C₁₄-HL). Background fluorescence was determined in Rm1021 devoid of plasmid pLK64 and is shown at the far right of the graph. Strains are included as follows: lane 1, Rm1021 (sinI⁺ expR); lane 2, Rm8530 (sinI⁺ expR⁺); lane 3, Rm11511 (sinI expR); lane 4, Rm11527 (sinI expR⁺); lane 5, Rm1021 sinR (sinR sinI⁺ expR); lane 6, Rm8530 sinR (sinR sinI⁺ expR⁺).