Role of carbon dioxide in acid resistance of Escherichia coli 

作成者 Sun, Lianle
作成者の別表記 孫, 蓮楽
キーワード等 acid risistance, acid challenge, adaptation, respose, Escherichia coli Carbon dioxide
日本十進分類法 (NDC) 490
内容 学位:千大院医薬博甲第医薬15号
抄録:It was reported that amino acids, such as arginine, glutamate, lysine, histidine and ornithine, participate in the acid resistance (AR) of Escherichia coli, and it was also proposed that amines produced from amino acids have an essential role in the acid resistance. In this study, the role of carbon dioxide was analyzed in the expression of the cad operon and acid resistance of Escherichia coli, The following results were obtained in this study: (i) When carbon dioxide was supplied at both the acid adaptation and challenge stages, the acid resistance of Escherichia coll increased more than that measured under other conditions, and the carbon dioxide supply was more significant at the adaptation than challenge stage, (ii) The expression of the cad operon was reduced by carbon dioxide at acidic pH. (iii) Respiration suppressed on the expression of the cad operon at acidic pH. (iv) Global regulators IHF and HU positively regulated the expression of the cad operon. (v) Glucose increased the expression of the cad operon under both aerobic and anaerobic growth conditions at acidic pH. (vi) A high level of the expression of the cad operon in crp mutant strain was suppressed by glucose. Based on these results, carbon dioxide was found to able to protect cells against cell death under acidic conditions in Escherichia coli. Also, IHF and HU was shown to play an indispensable role for the survival under extreme acidic condition via regulation of the expression in amino acid decarboxylases functioning at acidic pH in Escherichia coli.

コンテンツの種類 博士論文 Doctoral Thesis
DCMI資源タイプ text
ファイル形式 application/pdf
言語 英語

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