【摘要】 在格瑞斯瓦尔德磁螺菌(Magnetospirillum gryphiswa ldense)MSR-1中分别过量表达3种抗氧化酶Fe-超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶HPII,并分析过量表达这3种酶对趋磁螺菌MSR-1耐氧性的影响。通过PCR分别扩增大肠杆菌DH5α的Fe-超氧化物歧化酶(sodB)、谷胱甘肽过氧化物酶(btuE)、过氧化氢酶HPⅡ(katE)基因序列,将前两个片段分别连接到广宿主质粒pBBR1MCS-2上,后一个片段连接到广宿主质粒pBBR1MCS-5上,构建成表达质粒pBBR1MCS-sodB,pBBR1MCS-btuE和pBBR1MCS-katE,将3个质粒通过双亲接合转移的方法分别转入趋磁螺菌MSR-1。3种抗氧化酶过表达对趋磁螺菌MSR-1耐氧性影响的试验结果为过量表达Fe-超氧化物歧化酶对菌体生长影响不明显;过量表达谷胱甘肽过氧化物酶、过氧化氢酶HPII使趋磁螺菌MSR-1致死。上述试验结果表明抗氧化酶系在菌体耐氧过程中的全局协调调控的重要性。更多还原

【Abstract】 In this study,genes of Fe-superoxide dismutase(sodB),glutathione-peroxidase(btuE) and catalase HPII(katE) were over-expressed in the Magnetospirillum gryphiswaldense MSR-1,respectively.The effects of these three enzymes over-expression on the oxygen tolerance of MSR-1 were analyzed.sodB,btuE and katE gene were amplified by PCR from E.coli DH5α.sodB and butE gene were connected with pBBR1MCS-2,and katE gene was connected with pBBR1MCS-5 to construct the expression plasmid pBBR1MCS-sodB,pBBR1MCS-btuE and pBBR1MCS-katE,and then,these three expression plasmids were transferred to Magnetospirillum gryphiswaldense MSR-1 by conjugation,respectively.The results of tolerance of MSR-1 to oxygen showed that the over-expression of Fe-superoxide dismutase in MSR-1 had no obvious effects on cell growth,and the over-expression of glutathione-peroxidase and catalase HPⅡ resulted in the death of MSR-1.This research revealed that the coordination regulation of antioxidant enzyme system in bacteria was important.更多还原