Repression of toxin production by tryptophan in Clostridium botulinum type E
- 71 Downloads
Of the seven amino acids required by Clostridium botulinum type E, tryptophan is the most essential and may provide the cell with nitrogen. The addition of excess tryptophan (10–20 mM) or other nitrogenous nutrients to minimal growth medium markedly decreased toxin formation but did not affect growth in C. botulinum type E. On the other hand, the addition of an enzymatic digest of casein (NZ Case) stimulated toxin formation and overcame repression by tryptophan. Immunoblots of proteins in culture fluids using antibodies to type E toxin indicated that tryptophan-repressed cultures produced less neurotoxin protein. Inhibitors of neurotoxin did not accumulate in cultures grown in minimal medium supplemented with high tryptophan. The results suggest that tryptophan availability in foods or in the intestine may be important for toxin formation by C. botulinum type E.
Key wordsClostridium botulinum type E Tryptophan metabolism Nitrogen repression Botulinum neurotoxin formation
Unable to display preview. Download preview PDF.
- Cato EP, George L, Finegold SM (1986) Genus Clostridium Prazmowski 1880, 23AL. In: Sneath PHA, Mair NS, Sharpe ME, Holt JG (eds) Bergey's manual of systematic bacteriology Williams and Wilkins, Baltimore London Los Angeles Sydney, pp 1141–1200Google Scholar
- Dolman CE (1964) Botulism as a world health problem. In: Lewis KH, Lassel KJr (ed) Botulism, Proceedings of a symposium. U.S. Department of Health, Education, and Welfare, Cininatti, pp 5–32Google Scholar
- Eklund MW, Poyski F (1970) Distribution of Clostridium botulinum on the Pacific Coast of the United States. In: Herzberg M (ed) Proceedings of the first U.S.-Japan conference on toxic microorganisms. U.S. Department of the Interior, Washington, DC, pp 304–308Google Scholar
- Hauschild AHW, Gavreau L (1985) Food-borne botulism in Canada, 1971–1984. J Can Med Assoc 133: 1141–1146Google Scholar
- Reed LJ, Muench H (1938) A simple method of estimating fifty percent endpoints. Br J Exp Pathol 17: 335–341Google Scholar
- Schantz EJ, Kautter DA (1978) Standardized assay for Clostridium botulinum toxins. J Assoc Off Anal Chem 61: 96–99Google Scholar
- Smith L, Sugiyama H (1988) Botulism. Thomas, Springfield, ILGoogle Scholar
- Whitmer ME, Johnson EA (1988) Development of improved defned media for Clostridium botulinum serotypes A, B, and E. Appl Environ Microbiol 53: 753–759Google Scholar