2-heptyl-3-hydroxy-4 (1H) -Quinolone

2-heptyl-3-hydroxy-4 (1H) -Quinolone (Pseudomonas Quinolone Signal) is a quorum-sensing signalling molecule produced by Pseudomonas aeruginosa in response to increased cell density. It increases the expression of the lasB gene in P. aeruginosa, the secretion of the metabolites pyocyanin and the lectin PA-IL, as well as increasing biofilm production in P. aeruginosa populations. It also reduces the iron content of the P. aeruginosa growth medium when used at a concentration of 40 μM and acts as an iron chelator in iron sulphate solutions.