ボツリヌスC型，D型毒素遺伝子の解析による菌の分類に関する研究

Clostridium botulinum types C and D toxin production is governed by the specific bacteriophages. A type C phage,c-st,was isolated from a toxigenic strain of C-Stockholm,and its whole genome sequence was determined.The genome was a linear double-stranded 185,681bp DNA with a G＋C content of 26.2%, and identical 403-bp sequences were found at each end of the genome. From the DNA research, 198 potential protein-coding regions (ORFs)were identified. The genes for type C progenitor toxin and C3 exoenzyme were identified, but no type D toxin gene was found.A number of genes were homologous to those of a Bacillus subtilis bacteriophage,SP D. On Southern blot analysis between type C and D cell DNAs and the specific probes for H and L chains of C and D neurotoxins, it became clear that type C and D strains posses only one type of toxin gene.From these findings, it is concluded that cross-neutralization observed between toxins (types C and D)and their antiserums can be caused by the common-antigens in C and D toxins.

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