Control of Quorum Sensing Systems in Pseudomonas aeruginosa by Acyl Homoserine Lactone Analogues

Abstract

Three N-acylhomoserine lactone analogues, N-butyryl-, N-hexanoyl-, and N-octanoyl-cyclopentylamides were synthesized and examined for their effects on the las and rhl quorum sensing systems in Pseudomonas aeruginosa. The lasB- and rhlA-lacZ reporter gene assays revealed that these analogues inhibited the induction of the lasB and rhlA. N-Octanoyl-cyclopentylamide (C8-CPA) showed the strongest inhibitory effects on the induction of the reporter genes. C8-CPA depressed expression of elastase, which is one of virulence factors controlled by the quorum sensing systems in P. aeruginosa. The concentration of C8-CPA resulting in 50% inhibition of elastolytic activity was 220 µM. C8-CPA also inhibited biofilm formation of P. aeruginosa. These results demonstrate that N-acyl cyclopentylamides act as antagonists to intervene the quorum sensing systems in P. aeruginosa.