• bioassay;
  • LC-MS;
  • AHLs;
  • morphological observation


Quorum sensing (QS) is a system of cell-to-cell communication by means of intercellular signaling molecules to coordinate a set of targeted gene expression or repression in many Gram-negative bacteria; it plays important roles for bacteria in adaptation to adverse environmental conditions. In this study, we first demonstrated that Microcystis aeruginosa PCC-7820 could produce QS-related signal acylated homoserine lactones (AHLs) among the metabolite of axenic M. aeruginosa, based on bioassay and liquid chromatography–mass spectrometry (LC-MS) analysis. The concentration of the AHLs in the culture medium was cell density dependent and reached a maximum of 18 nM at 1.03 × 107 cells mL−1, 30 days after inoculation. The regulation mechanism of QS in M. aeruginosa and its possible role in bloom formation are discussed.