Clostridium perfringens KZ1340, previously classified as
Clostridium plagarum, is an isolate from Antarctic soil, and was identified as an α-, θ-, and κ-toxin non-producing variant. On Southern hybridization, the variant was found to be defective in the
pfoA (θ-toxin) gene, but the
plc (α-toxin) and
colA (κ-toxin) genes were present on the same
EcoRI fragment as in the standard strain, NCTC8237. Northern analysis revealed that mature
plc mRNA was transcribed in KZ1340 though less efficiently than in NCTC8237, while no mature
colA mRNA was present in KZ1340. After transformation of the
pfoA and
plc genes into the KZ1340 via shuttle vector, pJIR418, the
pfoA gene was successfully expressed but the
plc gene was not efficiently expressed, suggesting that in KZ1340 there is negative regulation of
plc gene expression. Toxin-deficient
C. perfringens KZ1340 might be a suitable host for expression analysis of the
pfoA gene and other clostridial virulence genes, if expressed efficiently, because it produces a small amount of extracellular toxins.
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