【作者】 潘硕； 耿伟涛； 汤伟； 王艳萍；

【Author】 Shuo Pan;Weitao Geng;Wei Tang;Yanping Wang;Tianjin University of Science & Technology;

【机构】 天津科技大学食品工程与生物技术学院；

【摘要】 植物乳杆菌MA2分离于西藏农家开菲尔粒中,前期研究表明该菌株在体外实验、细胞抗氧化模型和小鼠衰老模型中表现出了良好的抗氧化性能。利用分子生物学技术从该菌株中克隆出8个抗氧化功能相关的基因,它们在由H₂O₂诱导的氧化应激中发挥了重要的作用。本研究对植物乳杆菌MA2中谷胱甘肽过氧化物酶基因Gpx编码蛋白进行了异源表达。该酶的比活力均值为110.97U/mg,最适温度为37℃,最适pH为8.0。为了研究Gpx基因在菌株抵御氧化应激过程中的作用,将其克隆至乳酸菌表达载体pMG36e上,转化植物乳杆菌MA2形成过表达菌株。SDS-PAGE蛋白电泳显示该基因在MA2中成功进行了过表达。测定重组菌株抵御氧化应激的能力,并与野生型进行比较。发现在外源添加谷胱甘肽的条件下,重组菌株相较于野生型菌株表现出更强的抵御H2O2胁迫的能力。初步验证了Gpx编码的谷胱甘肽过氧化物酶在菌株抵御氧化应激过程中的作用,为深入研究乳酸菌的抗氧化机制提供了思路。更多还原

【Abstract】 In the previous work, Lactobacillus plantarum MA2, a strain with antioxidant capacity, was isolated from the kefir grains. The experiments have showed that L. plantarum MA2 had good resistance to oxidative stress in vivo and vitro. Eight antioxidant-related genes were identified by molecular biology technology, which play an important role in oxidative stress induced by H₂O₂. Heterologous expression of the protein encoding by glutathione peroxidase gene in L.plantarum MA2 was studied in this study. The activity of the enzyme was measured with 110.97 U/mg. The optimum temperature of the enzyme was 37 ℃, and the optimum pH was 8.0.In order to study the function of Gpx gene in the process of resisting oxidative stress, the gene was inserted into plasmid pMG36 e for the recombinant expression, and then transformed into L.plantarum MA2 to overexpress. The ability to resist oxidative stress was measured and compared with the wild strain. The research showed that the recombinant strain could tolerate more H₂O₂ stress than the wild strain with the addition of GSH. The function of glutathione peroxidase encoding by Gpx in the process of resisting oxidative stress was preliminarily verified. And the research provides a way for further study about the antioxidant mechanism of lactic acid bacteria.更多还原