Fig. 2.

(A) Polymorphism in the CqsS receptors of Vibrio species. The C170 residue in V. cholerae is substituted with phenylalanine in multiple Vibrio species including V. harveyi.B. The V. harveyi CqsS-dependent quorum-sensing response to various CAI-1 type molecules. Activation of bioluminescence expression was measured in V. harveyi strain JMH626 in the presence of exogenously added CAI-1 type molecules. ΔcqsA and WT denote cell-free culture fluids prepared from a V. harveyi mutant lacking or containing the CqsA synthase respectively. See Fig. 1A for the structures of the different molecules. RLU denotes relative light units which is Lux/OD₆₀₀.