We thank Er. K. Sekhar Director, DRDE Gwalior for providing all facilities and support required for this study. We also extend our gratitude to Dr. Praveen Kumar and Mr. P. C. Jatav for their invaluable help in animal experimentation.
Production and Stability Studies of a Neurotoxin Produced by Clostridium sp. RKD
Version of Record online: 30 JUN 2006
Journal of Food Science
Volume 71, Issue 3, pages M121–M125, April 2006
How to Cite
Dixit, A., Alam, S. I., Dhaked, R. K. and Singh, L. (2006), Production and Stability Studies of a Neurotoxin Produced by Clostridium sp. RKD. Journal of Food Science, 71: M121–M125. doi: 10.1111/j.1365-2621.2006.tb15635.x
- Issue online: 30 JUN 2006
- Version of Record online: 30 JUN 2006
- MS 20050456 Submitted 7/29/05, Revised 12/20/05, Accepted 1/26/06.
- Clostridium sp.;
- botulinum neurotoxin;
- mouse bioassay;
- toxin stability
ABSTRACT: A neurotoxigenic Clostridium sp. (RKD) isolated from intestine of decaying fish produced a neurotoxin that was neutralized by botulinum antitoxin (A+B+E) when tested by mouse protection bioassay. An amplicon of expected size (approximately 700 bp) was generated with primers specific for BoNT/B. Toxin was maximally released in the culture supernatant in the late stationary phase and was dependent on media composition. Growth was optimal in trypticase peptone yeast-extract glucose (TPYG) medium in a pH range of 7.5 to 8.0 and at a temperature between 35°C to 40°C while toxin production was optimum at 37°C (3 to 4 × 103 minimum lethal dose per milliliter) without any protease treatment. There was no correlation between growth and toxin production when cells were grown in media containing different concentrations of NaCl (0% to 5%). Toxin in the culture supernatant was more stable (50% reduction at 50°C in 90 min) than the partially purified fraction. Toxicity was destroyed gradually after increasing the number of freeze-thaw cycles and was almost completely inactivated after 5 cycles. It was completely inactivated by overnight treatment of 1 N NaOH while it retained 1.5% activity with a similar treatment with 1 N HCl.