QS activities were not affected by the deletion of mdpA and dppA3 genes.

(A-C) QS activity in PsdR variant derivatives with or without mdpA and dppA3 genes. PsdR variant strains carrying QS reporter plasmids were grown in casein broth for 12 h. Las (A), Rhl (B) and PQS (C) QS activities were estimated by the expression of PlasR-GFP, PrhlA-GFP and PpqsA-GFP reporter plasmids. Fluorescence values were determined using a flow cytometer (FITC channel). (B) Pyocyanin production (OD₆₉₅/OD₆₀₀ values) in shown strains. (C) Cyanide production by these strains. The cyanide-sensitive filter paper was photographed after growth of the bacteria in 24-well plates at 37°C for 18 h. Data are presented as mean ± SD (n ≧ 4).

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