Clostridium Molecular toxicity

O Sullivan G, Mohammed N, Foran P, Lawrence G, Dolly O (1999) Rescue of exocytosis in botulinum toxin A-poisoned chromaffin cells by expression of cleavage-resistant SNAP-25. Identification of the minimal essential C-terminal residues. J Biol Chem 274 36897-904 Oberg SG, Kelly RB (1976) The mechanism of beta-bungarotoxin action. I. modification of transmitter release at the neuromuscular junction. J Neurobiol 7 129 11 Ohishi I, Sugii S, Sakaguchi G (1977) Oral toxicities of Clostridium botulinum toxins in response to molecular size. Infect Immun 16 107-9... 

Ohishi, I., Sugii, S., Sakaguchi, G. (1977). Oral toxicities of Clostridium botulinum toxins in response to molecular size. Infect. Immun. 16 107-9. 

Enterotoxins. Toxic proteins formed by bacteria with molecular masses in the range from 27000 to 30000 which are usually excreted into the medium ( exotoxins). E. can be taken up with contaminated food or be formed by the bacteria colonizing the intestinal walls. Finally, the bacteria can penetrate the intestinal walls and then start to excrete the E. Some E. are thermally very stable and survive when food is boiled. E. from Salmonella and Staphylococcus species are the most frequent causes of food poisoning. Shortly after uptake, the symptoms of nausea, vomiting, diarrhea, and circulatory complaints occur. Deaths are rare and occur only when the subject is already in a weakened state. The sites of attack by E. vary, e.g., at intestinal epithelial cells or in the vegetative nervous system. For the production of antitoxins, E. are obtained by lysis of bacterial cells or from cell-free culture filtrates. E. have been detected, e. g., in the following bacterial species Bacillus cereus, Clostridium perfringens, Escherichia coli. Vibrio cholerae. Staphylococcus aureus, and Streptococcus faecalis. 

Fig. 4. Organization and fragmentation of botulinum neurotoxin. Botulinum neurotoxin is a protein with a molecular weight of 150,000 to 160,000. It is synthesized as a single chain polypeptide in the Clostridium bacteria. It is nicked by endogenous protease to yield a dichain molecule linked by a disulfide bond. This nicking is usually associated with activation of its toxicity. The nicked molecule is separated into heavy and light chains by reduction of the disulfide bond.

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