title: Evidence for quorum sensing in Clostridium botulinum 56A.
abstract: OBJECTIVE
  Experiments were designed to detect quorum-sensing signals produced by Clostridium botulinum.
  
  
  RESULTS
  Clostridium botulinum 56A cell-free supernatants obtained at the end of lag phase, the mid-exponential phase and early stationary phase of growth were assayed for bioluminescence in the Vibrio harveyi quorum-sensing assay system. Twelve and 16-h culture supernatants induced bioluminescence in the auto-inducer 2 (AI-2) but not the auto-inducer 1 (AI-1) assay. Intra-species quorum sensing was also assayed as the ability of the supernatants to promote spore germination and outgrowth in a microtitre plate system. Spore populations exposed to C. botulinum supernatant from the end of lag phase became positive for growth sooner than controls.
  
  
  CONCLUSIONS
  The influence of cell-free supernatant on ungerminated spores and detection of bioluminescence in the AI-2 assay are evidence for a signalling molecule(s) and provide a first step in characterizing C. botulinum quorum sensing.
  
  
  CONCLUSIONS
  This study suggests that spores do not behave independently of each other and may explain the inocula size effects observed in challenge studies. Whether AI-2 production in C. botulinum serves as an inter-species signal or as a detoxification mechanism remains to be determined.
authors.affiliation: Department of Food Science, Cook College, The New Jersey Agricultural Experiment Station, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901-8520, USA.
authors.forename: L
authors.initials: L
authors.lastname: Zhao
authors.forename: T J
authors.initials: TJ
authors.lastname: Montville
authors.forename: D W
authors.initials: DW
authors.lastname: Schaffner
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000032:analysis; D003014:Clostridium botulinum / Q000254:growth & development / Q000502:physiology*; D003470:Culture Media; D006714:Homoserine / Q000031:analogs & derivatives* / Q000032:analysis; D007783:Lactones / Q000032:analysis*; D008163:Luminescent Measurements / Q000379:methods; D015398:Signal Transduction; D013171:Spores, Bacterial / Q000187:drug effects / Q000254:growth & development; D014733:Vibrio / Q000737:chemistry
chemical_list: D003470:Culture Media; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine; C030654:N-(3-oxohexanoyl)-3-aminodihydro-2(3H)-furanone; D015107:4-Butyrolactone