The toxin of
Clostridium botulinum, which gives rise to food poisoning when ingested by man and animals, has been described as a true exotoxin. The toxin of
Cl. botulinum type A was obtained in crystalline form (Abrams
et al., 1946; Lamanna
et al., 1946) and those of other types have been purified (Lamanna and Glassman, 1947;
Duff
et al., 1957; Cardella
et al., 1958; Cardella
et al., 1960; Sterne and Wentzel, 1950; Gordon
et al., 1957) from cell free culture filtrate or whole culture. These reports also indicated that the toxins of
Cl. botulinum types A, B, C, D, and E are simple protein. Accordingly the procedures employed in purifying the toxins were those that had been used in the isolation of proteins.
The recent knowledge on the toxin production by
Cl. botulinum tells that the toxin is formed through activation of the atoxic precursor, which is synthesized in bacterial cells (Sakaguchi and Tohyama, 1955 a, b ; Boroff
et al., 1952; Bonventre and Kempe, 1960) . Activation is accomplished by certain bacterial enzymes (Sakaguchi and Tohyama, 1955 a, b ; Dolman, 1957; Bonventre and Kempe, 1960) or trypsin (
Duff
et al., 1956) .
It has also been found that type E toxin has neutral or weakly basic property, whereas the precursor strongly acidic property, which was ascribed to the ribonucleic acid in the precursor molecules (Sakaguchi and Sakaguchi, 1959) .
The authors attempted to purify type E botulinal toxin according to the principle derived from the foregoing knowledge. In the attempt, young bacterial cells were used as the starting material instead of cell free filtrate or whole culture. The extract of the bacterial cells contained a large amount of ribonucleic acid and the precursor. The trypsinization of the extract released the toxin free from ribonucleic acid, which was precipitated with ammonium sulfate. It was found that the toxin purified from the bacterial cells by the method reported here has a potency higher than those described by other workers (cordon
et al., 1957; Gerwing
et al., 1961; Fiock
et al., 1961) .
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