Solenopsin A, a Venom Alkaloid from the Fire Ant Solenopsis invicta, Inhibits Quorum-Sensing Signaling in Pseudomonas aeruginosa.

In Pseudomonas aeruginosa, quorum-sensing (QS) signaling regulates the expression of virulence factors and thus represents an attractive new target for anti-infective therapy. In the present study, we investigated whether solenopsin A, a venom alkaloid from the fire ant, possessed agonistic or antagonistic QS signaling activity in P. aeruginosa.We evaluated the modulation of virulence factor expression and transcriptional levels of QS-regulated genes in P. aeruginosa by solenopsinAand demonstrated that solenopsin A efficiently disrupted QS signaling. Interestingly, exogenously added C₄-homoserine lactone (HSL), but not 3-oxo-C₁₂-HSL, restored P. aeruginosa QS signaling, suggesting that solenopsin A targets the C₄-HSL- dependent rhl QS system. [ABSTRACT FROM AUTHOR]