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  • 學位論文

貝萊斯芽孢桿菌AC菌株的鑑定及抗氧化能力分析

Identification of a Bacillus sp. AC strain and analysis of its antioxidant ability

指導教授 : 劉嚞睿
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摘要


近年來,由於科學證據不斷地表明益生菌對人類健康有益,有關益生菌的保健食品已經在商業市場上占據一席之地。益生菌具有免疫調節、抗發炎、抗氧化等功效,且益生菌易被攝取和其經濟價值高。本實驗針對土壤中篩選出的Bacillus sp. AC,進行基本分子與生化特性分析。經鑑定試驗結果顯示,AC屬於Bacillus velezensis。本實驗並探討AC及其産物之抗氧化活性,一方面從清除1,1-diphenyl-2-picrylhydrazyl(DPPH)自由基能力測定和清除氫氧自由基能力測定;另一方面,以人類胚肺成纖維細胞MRC-5建立早期衰老細胞模式,以過氧化氫(H2O2)誘導MRC-5使細胞衰老,並以流式細胞儀分析細胞老化週期,以及將芽孢桿菌及其產物以預處理方式在過氧化氫誘導細胞老化前給予保護作用。結果顯示,Bacillus velezensis AC其清除DPPH自由基能力和清除氫氧自由基能力在特定濃度下有顯著提升。在過氧化氫誘導氧化損傷之前,MRC-5細胞用AC或其細胞成分進行預處理。對MRC-5細胞氧化損傷主要指標為超氧化物歧化酶(superoxide dismutase, SOD)、穀胱甘肽過氧化物酶(glutathione peroxidase, GPx)等抗氧化酶的表達進行分析,結果表明其胞內液(intracellular fraction, ICF)具有較高的抗氧化酶活性。在這項研究中,我們證明 B. velezensis AC 的細胞胞內液具有顯著的自由基清除能力和抗氧化活性。通過細胞模型實驗,我們也證明 B. velezensis AC 可能是益生菌食品補充劑的候選者。綜上所述, B. velezensis AC 具有清除自由基的分子,且富含抗氧化活性,期望未來在動物實驗上能有好的表現並發展爲健康保健食品。

並列摘要


Probiotic health foods belong to an essential health supplement category in the commercial market. There is ever-growing scientific evidence demonstrating their health promoting benefits to human and animal health. Administration of probiotics has been demonstrated to confer immunomodulatory, anti-inflammatory, and antioxidant effects on the host. In this research, Bacillus sp. AC, a bacterial strain previously isolated from soil, was characterized and investigated for its potentiality as food or feed additives. Based on molecular and biochemical identification, Bacillus sp. AC strain belongs to the species Bacillus velezensis. The antioxidant activities, including the scavenging 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) radicals and hydroxyl radicals ability, of B. velezensis AC and its intracellular and cell wall fractions were analyzed. The results demonstrated that the intracellular fraction (ICF) of B. veleznesis AC showed a significant high scavenging ability against DPPH free radicals and hydroxyl radicals. For further demonstration of the beneficial effects of B. veleznesis AC, a senescence cell model by treating human lung fibroblast MRC-5 cells with hydrogen peroxide was established, and the flow cytometric analysis was performed to study the cell cycle of these oxidative damage cells. Before hydrogen peroxide (H2O2) induced oxidative damage, the MRC-5 cells were pretreated with B. veleznesis AC or its cellular fractions. The analyses of major indices of oxidative damage and the expressions of antioxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the MRC-5 cells, the results showed that ICF has high antioxidant enzyme activity and ICF also has significantly difference with negative control in the GPx assay. In this study, we demonstrated the intracellular fraction of B. velezensis AC has a significant free radical scavenging ability and antioxidant activity. With ongoing cell model experiments, we aim to demonstrate B. velezensis AC could be a candidate for probiotic food supplement.

參考文獻


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