Susceptibility of mink to Clostridium botulinum type C toxin

Investigations to determine the exact susceptibility of mink to Clostridium botulinum type C toxin clearly showed that mink were considerably less resistant to this toxin than has previously been described. Mink weighing approximately 900 g were killed by 360 MLD when toxin was mixed into the feed. By subcutaneous injection, the lethal dose was determined to be in the range of 18 to 36 MLD.When comparing the susceptibility per g of body weight after parenteral application of the toxin, mink proved to be less resistant than mice to this type of toxin. Continued feeding tests in mink with suspected material is pointed out as a preferable method for practical demonstrations of Clostridium botulinum type C toxin in cases where the toxin content in the suspected material is very low (1 MLD per g or less).     

Susceptibility of mink to Clostridium botulinum type E toxin

Experiments aiming at elucidation of the toxicity of Clostridium botulinum type E for mink are described. The observations indicate that amounts in the order of 2 x10^s intraperitoneal MLD (mice) or approximately 200 MLD per g of type E toxin will kill a mink after oral administration. The symptoms observed in the animals were atypical as there was an unusually short period between administration of the toxin and the onset of symptoms and deaths of the animals. Similar results were obtained when Clostridium botulinum type E toxin was fed to Swiss mice. When mice were protected by subcutaneous injections of type E antitoxin prior to feeding the animals survived without showing any symptoms.Subcutaneous injection of type E toxin in amounts of the order of 2 x10^s intraperitoneal MLD (mice) killed mink, and typical symptoms of botulism were observed. This quantity corresponds to ap-proximately 2 intraperitoneal MLD (mice) per g.Comparison is made with previous observations obtained in similar experiments made with Clostridium botulinum type C toxin. It is shown that mink arc substantially less susceptible to type E than to type C toxin when the toxins are given by mouth. On this basis previous results in reports on outbreaks of botulism in mink caused by Clostridium botulinum type E may be regarded as questionable.     

Association between the cell-wall peptidoglycan and the progenitor toxin of Clostridium botulinum type C

Clostridium botulinum type C progenitor toxin with a molecular weight of 500 k daltons (C1 L toxin), purified from the bacterial cells, bound at pH 2 to the cell-wall peptidoglycan derived from certain strains. The carbohydrate moiety of the peptidoglycan contained arabinose and galactose at a certain ratio, both of which may directly be associated with the binding. The binding, being dependent on the quality and quantity of the sugars, enhanced the oral toxicity of the toxin to the chicken as well as the mouse.     

Detection of Clostridium botulinum types C and D toxin by ELISA

An ELISA to detect Clostridium botulinum type D toxin was developed using polyclonal antibodies to a semi-purified toxic complex of the neurotoxin. Sensitivity of the ELISA for detecting type C and type D toxin compared with mouse inoculation was 70% and specificity 96% on samples from animals with botulism diagnosed on clinical signs and herd history. However, both mouse inoculation and the ELISA failed to detect toxin in many animals with a presumptive diagnosis of botulism. Some cross-reaction was seen with Clostridium novyi type A, but not with other clostridial species. While the ELISA described here cannot replace mouse inoculation for the diagnosis of botulism, it is a useful additional test.     

肉毒梭菌毒素灭鼠研究进展

就肉毒梭菌毒素用于灭鼠的研究和应用情况进行了综述，充分肯定了C型肉毒梭菌毒素灭鼠制剂毒力强，适口性好，对非靶动物毒性低，作用缓慢，无2次中毒，易降解和适合于规模灭鼠的特点，为鼠害防治提供了新的思路。     

The taxonomic position of Clostridium botulinum type c.

Experimental evidence is produced to justify abandoning the practice of subdividing Costridium botulinum Type C into type Calpha and Cbeta.     

The gene for component-II of botulinum C2 toxin

The gene encoding component-II of the Clostridium botulinum C2 toxin was cloned from the chromosomal DNA of C. botulinum type C strain (C)-203U28, and the nucleotide sequence was determined. The gene (bc2h) encodes a protein with 721 amino acid residues and is located at 247 bp downstream of the gene for component-I. The N-terminal 16 amino acids were identical to those obtained by analysis of the purified component-II toxin. The ORF for bc2h had only 39% homology at the amino acid level with the C. perfringens iota-Ib protein and an ATP/GTP binding site which is present in the iota-Ib protein is missing from the protein encoded by bc2h. Both genes had a homologous region that predicts a transmembrane segment.     

Proteases of Clostridium botulinum. VI. The role of trypsin, Clostridium botulinum proteases and protease inhibitors in the formation and activation of toxin in growing cultures of Clostridium botulinum

In this study the influence of bovine serum protease inhibitors, trypsin and proteases produced by different types of Clostridium botulinum has been investigated. Trypsin and botulinum proteases had the capability of increasing the toxicity in growing cultures in Clostridium botulinum types A, B and E. Trypsin increased the toxin level to a greater extent than proteases from Clostridium botulinum types A, B, C and F. Protease inhibitors did not influence the toxin formation to any extent compared with the controls. The combined effects of proteases and protease inhibitors on the development of toxin in Clostridium botulinum type B were also investigated by adding proteases and protease inhibitors to the same culture at different time intervals. Protease inhibitors did not reduce the toxicity of the cultures as compared to the controls. Altogether a complex relationship seems to exist between protoxin, toxin, proteases and inhibitors in the culture, and the order and time sequence of addition seem to be of importance. The results obtained in this investigation indicate that proteases of Clostridium botulinum play a part in the formation and/or activation of toxin in growing cultures of proteolytic strains such as Clostridium botulinum types A and B. As to the activation of protoxin and progenitor toxin produced by non-proteolytic Clostridium botulinum types B and E, botulinum proteases showed a marked capability of increasing the toxicity in these cultures. Trypsinization may be valuable for the detection of Clostridium botulinum types A and B in foods, as well as for type E, where it is commonly used.     

Oral dosing of mice with Clostridium botulinum type C cultures and culture filtrates

In two of 14 tests in which adult mice were dosed per os, whole broth culture of Clostridium botulinum type C was more lethal than culture sterilised by membrane filtration. The results indicated that occasionally--though not usually--significant bacterial multiplication and toxigenesis occurred in the gut.