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Updated: Aug 13, 2026

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Published on: May 23, 2020
Evidence for quorum sensing in Clostridium botulinum 56A
L Zhao1, T J Montville, D W Schaffner
1Department of Food Science, Cook College, The New Jersey Agricultural Experiment Station, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901-8520, USA.
Aims:
Experiments were designed to detect quorum-sensing signals produced by Clostridium botulinum.
Methods And 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.
Significance And Impact Of The Study:
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.
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