Lactobacillus reuteri於酸性與膽鹽環境中之蛋白質體研究;The proteomic analsis of proteins induced by low pH and bile salts in Lactobacillus reuteri

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题名:	Lactobacillus reuteri於酸性與膽鹽環境中之蛋白質體研究;The proteomic analsis of proteins induced by low pH and bile salts in Lactobacillus reuteri
作者:	黃郁芳;Yu-Feng Huang
贡献者:	生命科學研究所
关键词:	蛋白質體學;proteomics;Lactobacillus reuteri
日期:	2002-07-02
上传时间:	2009-09-22 10:16:49 (UTC+8)
出版者:	國立中央大學圖書館
摘要:	摘要乳酸菌一般常用來作為益生菌與食品發酵微生物。在目前已知之腸內菌中，Lactobacillus reuteri為分佈較為廣泛之菌種。當乳酸菌藉由食物之攝取進入胃腸道，將會分別在胃部遭受酸之刺激與小腸中膽鹽之壓力。透過在不同程度的酸與不同膽鹽濃度之活性測試，發現pH 2.0與0.3%膽鹽濃度會對L. reuteri造成壓力。此菌屬耐酸性之乳酸菌，具相當高之產業價值，以pH 2.0處理3小時，存活率可達48%；而在含0.3%膽鹽環境則2小時後僅達3.0%。本研究擬以蛋白體學方法研究二種胃腸道壓力對此菌造成之蛋白質表現差異。以二維電泳分離蛋白質，經分析為被誘發者，續以介質輔助雷射揮離離子化飛行時間（matrix-assisted laser desorption ionization-time of flight, MALDI-TOF）質譜儀分析並透過在資料庫中比對?肽質量指紋以鑑定之。比較各實驗組中蛋白質之表現，分別在pH 2.0酸性環境、含0.3%膽鹽濃度與模擬腸道條件下，各有11、9與6個蛋白質點被誘發。在本研究中除了參與轉錄調節作用之?54與?S外，與蛋白質摺疊相關之GroEL以及參與脫氮作用之nitrous oxide reductase (NosL)亦在二種壓力環境中被誘發。酸休克蛋白、ornithine carbamoyltransferase、ATPase ?與?次單位只在酸性環境中被誘發。而保護蛋白GroES和ClpB、逆境蛋白AhpC、ATP-binding cassette (ABC) transporter則只有在處理膽鹽時增加其表現量。再者可以在膽鹽存在之環境中被誘發之D-alanine-D-alanine lygase是有關膽鹽可能造成細胞壁傷害之發現。 Abstract Lactic acid bacteria (LAB) are commonly used as probiotics or starter cultures in the fermented foods. Among them, Lactobacillus reuteri is the only enterolactobacillus known to be indigenous in a broad spectrum of hosts. When lactic acid bacteria were eaten with food, the microorganisms suffer the stresses of acid and bile salts in stomach and in duodenum, respectively. To investigate the proteome of stress response from lactic acid bacteria under these two types of stress, the viability of the bacterium under different pH and bile salts concentration was studied. Treated with Men-Rogosa-sharp (MRS) (pH 2.0) medium for 2 hours, 48% of Lactobacillus reuteri ATCC23272 survived. The survival rate was 3.0% under 0.3% bile salts in MRS (pH 5.7) medium for 2 hours. The proteomes of L. reuteri ATCC23272 treated with pH 2.0 or 0.3% bile salts were analyzed by two-dimensional polyacrylamide gel electrophoresis (2-DE) and quantified by Commassie blue staining. The peptide mass fingerprints of induced proteins were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry via searching the SWISS-PROT and TrEMBL databases. Comparing the protein patterns of cell extracts from MRS media, there are 11, 9, and 6 spots induced by pH 2.0, 0.3% bile salts and the combination of two conditions, respectively. In addition to ?54 and ?S involved in the regulation of transcription, protein involved in folding such as GroEL is induced by two types of stress. Nitrous oxide reductase (NosL) is also induced by two types of stress. The acid shock protein, ornithine carbamoyltransferase, ATPase ? and ? subunit are acid response proteins induced by acid only. And GroES, ClpB, alkyl hydroperoxide reductase (AhpC) and ATP-binding cassette (ABC) transporter are induced when L. reuteri is treated with bile salts. The induction of D-alanine-D-alanine lygase (Ddl) by bile salts indicates bile salts may damage bacterial cell wall.
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