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

佐藤 成美

出版者

社団法人 腐食防食協会

雑誌

防蝕技術 (ISSN:00109355)

巻号頁・発行日

vol.9, no.2, pp.79-80, 1960-02-25 (Released:2009-11-25)

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.

著者

佐藤 成美 山内 さつき 高林 範子 石井 裕

出版者

岡山県立大学保健福祉学部

雑誌

岡山県立大学保健福祉学部紀要 = BULLETIN OF FACULTY OF HEALTH AND WELFARE SCIENCE, OKAYAMA PREFECTURAL UNIVERSITY (ISSN:13412531)

巻号頁・発行日

vol.21, pp.45-55, 2015-03-12

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本研究の目的は、マスク着用による音声への影響と話し手の音声の特徴が聞き手の聞き易さにどう影響しているかを、音声分析により明らかにすることである。音声実験では、被験者6 名に日常生活会話と同程度に話す「標準音声」、大きく・はっきり・ゆっくりと、を意識して話す「明確音声」をマスク非着用時と着用時で録音した。次に聴取実験では、別の被験者10 名に録音した音声を聞かせ、どちらが聞き易いか【声の大きさ・声の高さ・話す速度・間隔・アクセント】を基準に評価させた。その結果、マスク着用時の「標準音声」と「明確音声」の声の大きさには、有意な差は認められなかった。これは、マスク着用により発声が妨げられたことによるものと考えられた。また、聞き易い音声とは声の大きさだけではなく、抑揚をつけ話す速度も遅くすることが聞き易い音声にとって必要な項目であり、マスク着用時の円滑なコミュニケーションに繋がるという示唆が得られた。