【摘要】 为了查明Cu²⁺胁迫影响Acidithiobacillus ferrooxidans（At.ferrooxidans）亚铁氧化代谢机制,本研究设计了由低到高Cu²⁺浓度（0～25 g/L）胁迫环境,利用邻菲啰啉分光光度法、实时荧光定量PCR和循环伏安法等分析手段分别探究了不同Cu²⁺浓度胁迫下At.ferrooxidans亚铁氧化率、亚铁氧化电子传递链rus operon相关基因表达及胞外电子传递的响应情况。结果表明:Cu²⁺胁迫浓度由0 g/L增加至25 g/L时,At.ferrooxidans菌亚铁氧化活性显著降低(25 g/L Cu²⁺,对应下24 h亚铁氧化抑制率约为50%),rus operon相关基因表达显著下调（尤其是细胞内膜蛋白编码基因Cyc1和细胞色素c氧化酶编码基因CoxBACD分别下调12.4倍和4～6倍）,Fe²⁺氧化胞外传递电子能力也降低(循环伏安曲线还原峰值29.0μA(对照组,0 g/L Cu²⁺)和26.5μA(25 g/L Cu²⁺))。综上所述,高浓度Cu²⁺胁迫引起At.ferrooxidans菌亚铁氧化代谢Rus operon相关基因表达显著下调,造成胞外电子传递速率降低,最终导致At.ferrooxidans菌亚铁氧化率降低。更多还原

【Abstract】 The effects of Cu²⁺ stress（0-25 g/L） on the ferrous oxidation efficiency,expression of Rus operon genes and extracellular electron transfer of Acidithzobaczllus ferrooxidans（At.ferrooxidans） were investigated by using phenanthroline spectrophotometry,real-time quantitative PCR and cyclic voltammetry.The obtained results indicate that the increased concentrations of Cu²⁺ stress from 0 g/L to 25 g/L inhibit the ferrous oxidation activity of At.ferrooxidans.Under the stress of 25 g/L Cu²⁺,the 24 h ferrous oxidation inhibition efficiency is about 50% in comparison to the control(0 g/L Cu²⁺).The high concentration of Cu²⁺ stress also decreases the transcriptional levels of Rus operon genes.Especially,Cycl and CoxBACD are decreased by 12.4 fold and 4-6 fold,respectively.Meanwhile,the decreased rate of extocelluler electron transfer in At.ferrooxidans under the stress of 25 g/L Cu²⁺（26.5 μA） is found in comparison to that in the control(0 g/L Cu²⁺,29.0 μA).In conclusion,the high concentration of Cu²⁺ stress results in the down-regulated expression of Rus operon genes related to Fe²⁺ oxidation,afterwards inhibiting the electron transport from Fe²⁺ oxidation,and finally leading to a decrease in the rate of ferrous oxidation.更多还原