著者

川田 十三夫 佐藤 成美 山下 彦王 宅見 賢二 采見 憲男 渡辺 健二

出版者

公益社団法人 日本食品衛生学会

雑誌

食品衛生学雑誌 (ISSN:00156426)

巻号頁・発行日

vol.9, no.5, pp.358-363, 1968

被引用文献数

1

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Cells of <I>Clostridium botulinum</I> type A strain 190 grown in thioglycolate medium (GYPT medium) autolysed after having reached a maximum growth. This strain was dissociated into large and small colony-forming types in semisolid media. The cells obtained from the large colony type autolysed more rapidly than those from small one. Washed cells harvested at logarithmic growth phase lysed in phosphate buffer at 37&deg;C within 2-3 hours. Autolysis rose above pH 6.0 and was optimal near pH 7.0. The potential for autolysis reached a maximum toward the end of the logarithmic growth phase and thereafter the cells became resistant to autolysis. The autolytic activity was destreyed by heating the cells at 60&deg;C for 10 minutes and was slightly affected by cysteine (10<SUP>-2</SUP>M), N-ethylmaleimide (10<SUP>-2</SUP>M) and mercaptoethanol (10<SUP>-1</SUP>M).<BR>During autolysis nitrogen, protein, nucleic acids, reducing sugars, amino sugars and botulinum toxin were released from the cells as the reduction of the turbidity in cell suspension occurred. Electron microscopic observations on the process of autolysis revealed that the partial lysis of walls occurred first at the end of the organism and the cytoplasmic contents were lost through such lesions. The lysis of the wall centripetally spread and finally the morphological entity of the wall was completely lost. From these findings it is suggested that the autolysis may be proceded by auto-digestion of the cell wall at the end of the organism.

著者

川田 十三夫 宅見 賢二 佐藤 成美 山下 彦王

出版者

Japanese Society for Food Hygiene and Safety

雑誌

食品衛生学雑誌 (ISSN:00156426)

巻号頁・発行日

vol.9, no.5, pp.364-368, 1968-10-05 (Released:2010-03-01)

参考文献数

15

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Most of the cells of Clostridium botulinum type A strain 190 harvested at logarithmic growth phase in GYPT medium were converted autolytically to spheroplasts in 0.5M sucrose-phosphate buffer within 2-3 hours at 37°C. Electron microscopic observations on the formation of spheroplasts demonstrated that the cytoplasmic contents were extruded through partly dissolved walls at the end of the organism and formed spherical bodies.Crude wall fraction, isolated from logarithmic phase cultures by sonication and fraction-ation, rapidly autolysed in phosphate buffer. The wall fraction isolated from the large colony type of the strain lysed more rapidly than those from the small one as reported on the whole cells. Reducing sugars and amino sugars being main constituents of the wall were released from the wall fraction as wall-autolysis occurred. Electron micorscopic study showed that the rigid structure of the wall was completely lost and only fragile membranous or amorphous components remained as residues. Heated wall preparations digested with trypsin and nagarse were dissolved by a soluble wall-autolysate, but not by a soluble cytoplasmic fraction. It seems likely that autolytic enzyme system may exist at or near the cell wall.