In recent years, bioremediation is considered as an efficient method to remove the pollutants from the industrial wastewater. In this study, quantitative gene expressions (Real-time RT-PCR) of mtr gene cluster (mtrA, mtrB, mtrC, mtrD, mtrE, mtrF and omcA) in five different uranium concentrations (0.1, 0.25, 0.5, 1 and 2 mM) were performed with ICP and microscopic live cell counting analysis under anaerobic condition, by Shewanella RCRI7 as a native bacterium. The results indicated that the amount of uranium removal and live-cell counting were decreased in the higher uranium concentrations (1 and 2 mM), due to the uranium toxicity, suggesting 0.5 mM as the optimum uranium concentration for Shewanella RCRI7 resistance. The expression of mtrCED and omcA genes presented increasing trend in the lower uranium concentrations (0.1, 0.25 and 0.5 mM) and a decreasing trend in 1 and 2 mM, while mtrABF, presented an inverse pattern, proving the alternative role of mtrF for mtrC and omcA, as the substantial multiheme cytochromes in Extracellular Electron Transfer (EET) pathway. These data are a proof of these gene vital roles in the EET pathway, proposing them for genetic engineering toward EET optimization, as the certain pathway in heavy metal bioremediation process.

中文翻译：

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铀去除过程中希瓦氏菌 RCRI7 中 mtr 簇表达的评估

近年来，生物修复被认为是去除工业废水中污染物的有效方法。在本研究中，mtr 基因簇（mtrA、mtrB、mtrC、mtrD、mtrE、mtrF 和 omcA）在五种不同铀浓度（0.1、0.25、0.5、1 和 2 mM）中的定量基因表达（实时 RT-PCR） ) 在厌氧条件下通过 ICP 和显微活细胞计数分析进行，由 Shewanella RCRI7 作为天然细菌进行。结果表明，由于铀毒性，在较高的铀浓度（1 和 2 mM）下，铀去除量和活细胞计数降低，表明 0.5 mM 作为 Shewanella RCRI7 抗性的最佳铀浓度。mtrCED 和 omcA 基因的表达在较低的铀浓度（0.1、0.25 和 0. 5 mM) 和 1 和 2 mM 的下降趋势，而 mtrABF 呈现相反的模式，证明 mtrF 对 mtrC 和 omcA 的替代作用，作为细胞外电子转移 (EET) 途径中的大量多血红素细胞色素。这些数据证明了这些基因在 EET 途径中的重要作用，建议将它们用于 EET 优化的基因工程，作为重金属生物修复过程中的某些途径。