FIG 4.

rio84 encodes the signaling peptide for the Rgg1518 quorum sensing system. (A) Schematic of the luciferase reporter integrated into the bgaA locus of S. pneumoniae D39. The black arrows indicate the promoter. (B) P₁₅₁₇ is induced when grown in CDM and upon the constitutive expression of rio84 in the background of the Δrio83 Δrio84 strain. (C) Induction of P₁₅₁₇ upon the addition of 10 μM synthetic C6, C8, and C12 Rio84 peptides. The data shown are representative of results from three independent experiments.