School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
College of Life Science and Technology, Southwest Minzu University, Chengdu 610041, China.
Int J Mol Sci. 2019 Apr 10;20(7):1766. doi: 10.3390/ijms20071766.
Two strains, the first being a highly stress-resistant ATCC 9372 strain and the Ua strain identified from a chromium mine by our lab, differ in their abilities to tolerate and remove Uranium (VI) from contaminated water. An increase in U(VI) concentration in growth media led to a decrease in the tolerance and bio-remedial capacity of both strains. However, under high concentrations of U(VI) in the growth media, the ATCC 9372 strain demonstrated a higher tolerance and a higher removal capacity than the Ua strain. Two approaches, transcriptome sequencing and transgenic technology, were used to elucidate the relationship between particular genes within these two strains and their U(VI) removal capacity. Sequencing confirmed the expression of two genes unique to the Ua strain, previously designated B and A. They encode putative proteins that show the highest levels of identity to carbonic anhydrase and cytochrome bd terminal oxidase I, respectively. Using the pBE-S DNA vector, B and A were transformed into the ATCC 9372 strain of . Under a U(VI) concentration of 120 mg/L, the removal rates of the transgenic ATCC 9372-B and ATCC 9372-A strains decreased by 7.55% and 7.43%, respectively, compared to the removal rate of the control strain transformed with empty plasmid. The results suggest that both A and B genes have a negative influence on the uranium removing capacity of . This finding will help to elucidate the molecular mechanisms of uranium removal by bacteria.
两种菌株，第一种是高度抗应激的 ATCC 9372 菌株，第二种是我们实验室从铬矿中鉴定出的 Ua 菌株，它们在耐受和去除受污染水中铀（VI）的能力上有所不同。生长培养基中 U(VI)浓度的增加导致两种菌株的耐受性和生物修复能力下降。然而，在生长培养基中存在高浓度的 U(VI)的情况下，ATCC 9372 菌株表现出比 Ua 菌株更高的耐受性和更高的去除能力。采用转录组测序和转基因技术两种方法，阐明了这两种菌株中特定基因与其 U(VI)去除能力之间的关系。测序证实了 Ua 菌株中两个特有基因 B 和 A 的表达，这两个基因先前被指定为 B 和 A。它们编码的假定蛋白分别与碳酸酐酶和细胞色素 bd 末端氧化酶 I 的同源性最高。使用 pBE-S DNA 载体，将 B 和 A 转化到 ATCC 9372 菌株中。在 U(VI)浓度为 120mg/L 时，与转化空质粒的对照菌株相比，转基因 ATCC 9372-B 和 ATCC 9372-A 菌株的去除率分别下降了 7.55%和 7.43%。这表明 A 和 B 基因对 的铀去除能力都有负面影响。这一发现将有助于阐明细菌去除铀的分子机制。
