Involvement ofN‐acyl‐l‐homoserine lactone autoinducers in controlling the multicellular behaviour ofSerratia liquefaciens

摘要

SummarySeveral bacterial species possess the ability to differentiate into highly motile swarmer cells capable of rapid surface colonization. InSerratia liquefaciens, we demonstrate that initiation of swarmer‐cell differentiation involves diffusible signal molecules that are released into the growth medium. Using high‐performance liquid chromatography (HPLC), high resolution mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, we identifiedN‐butanoyl‐l‐homoserine lactone (BHL) andN‐hexanoyl‐l‐homoserine lactone (HHL) in cell‐freeSerratiaculture supernatants. BHL and HHL are present in a ratio of approximately 10:1 and their structures were unequivocally confirmed by chemical synthesis. Theswrlswarmer initiation) gene, the predicted translation product of which exhibits substantial homology to the Luxl family of putativeNacyl homoserine lactone (AHL) synthases is responsible for directing synthesis of both BHL and HHL. In answrlmutant, swarming motility is abolished but can be restored by the addition of an exogenous AHL. These results add swarming motility to the rapidly expanding list of phenotypes known to be controlled throu