Identification of Quorum-Sensing Molecules of -Acyl-Homoserine Lactone in Strains by Liquid Chromatography-Tandem Mass Spectrometry.

Many Gram-negative bacteria can regulate gene expression in a cell density-dependent manner via quorum-sensing systems using -acyl-homoserine lactones (AHLs), which are typical quorum-sensing signaling molecules, and thus modulate physiological characteristics. -acyl-homoserine lactones are small chemical molecules produced at low concentrations by bacteria and are, therefore, difficult to detect. Here, a biosensor system method and liquid chromatography-tandem mass spectrometry were combined to detect and assay AHL production. As demonstrated by liquid chromatography-tandem mass spectrometry, CGMCC No. 2955, a Gram-negative acetic acid-producing bacterium and a typical bacterial cellulose (BC) biosynthesis strain, produces six different AHLs, including -acetyl-homoserine lactone, -butanoyl-homoserine lactone, -hexanoyl-homoserine lactone, -3-oxo-decanoyl-homoserine lactone, -dodecanoyl-homoserine lactone, and -tetradecanoyl-homoserine lactone. strain SX-1, another Gram-negative acetic acid-producing bacterium, which can synthesize BC, produces seven different AHLs including -acetyl-homoserine lactone, -butanoyl-homoserine lactone, -hexanoyl-homoserine lactone, -3-oxo-octanoyl-homoserine lactone, -decanoyl-homoserine lactone, -dodecanoyl-homoserine lactone, and -tetradecanoyl-homoserine lactone. These results lay the foundation for investigating the relationship between BC biosynthesis and quorum-sensing systems.