- 學位論文
Lactobacillus casei ATCC 334 的AI-2生產、純化與分析
Production、purification and analysis of AI-2 of Lactobacillus casei ATCC 334
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摘要
Quorum sensing是一種細菌會偵測族群密度而改變性狀的現象，藉由分泌一些被稱為autoinducer的信號分子並偵測其濃度來達成。Autoinducer-2 (AI-2)是一種通用於多種細菌間的信號分子，由LuxS所合成，只要具有luxS基因都有可能分泌AI-2。Lactobacillus casei ATCC 334是一株基因體全定序的乳酸菌，具有luxS基因，也可偵測到AI-2活性。為了研究AI-2在Lactobacillus casei ATCC 334會控制哪些性狀，以直接添加AI-2的方式來做研究。所以我們純化了LuxS的重組蛋白，以之合成AI-2並純化之。以GC-MS及NMR氫原子光譜確認了合成的AI-2與文獻中記載的一樣。以AI-2測試是否會影響乳酸菌的biofilm、抑菌力、抗氧化力三種性狀，結果是不會影響。
並列摘要
Quorum sensing is a phenomenon with which bacteria detect high population density and change their phenotype. Bacteria secrete some signal molecules called autoinducer, then detect autoinducer concentration to achieve quorum sensing. Autoinducer-2 (AI-2) is a signal molecule in common use among many bacterial species, and it is synthesized by LuxS . If there is a luxS gene in a bacterial genome, the bacteria may secrete the AI-2. Lactobacillus casei ATCC 334 is a lactic acid bacteria of which the genome has been sequenced completely. It has luxS gene, and AI-2 activity can be detected . In order to study which phenotype is controlled by AI-2 in Lactobacillus casei ATCC 334, we directly added AI-2 to incubate Lactobacillus casei ATCC 334. We purified recombinant protein LuxS and used it to synthesize AI-2 for purification. We used GC-MS and NMR proton spectrum to determine whether the enzyme product was AI-2. We tested the effects of AI-2 on three phenotypes：biofilm、antibacterial ability and antioxidative ability. There is no significant difference.
參考文獻
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