Chang Jin-Soo, Yoon In-Ho, Kim Kyoung-Woong
Arsenic Geoenvironment Laboratory (National Research Laboratory), Department of Environment Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.
J Microbiol Biotechnol. 2007 May;17(5):812-21.
The ecosystems of certain abandoned mines contain arsenic-resistant bacteria capable of performing detoxification when an ars gene is present in the bacterial genome. The ars gene has already been isolated from Pseudomonas putida and identified as a member of the membrane transport regulatory deoxyribonucleic acid family. The arsenite-oxidizing bacterial strains isolated in the present study were found to grow in the presence of 66.7 mM sodium arsenate (V; Na2HAsO4.7H2O), yet experienced inhibited growth when the sodium arsenite (III; NaAsO2) concentration was higher than 26 mM. Batch experiment results showed that Pseudomonas putida strain OS-5 completely oxidized 1 mM of As(III) to As(V) within 35 h. An arsB gene encoding a membrane transport regulatory protein was observed in arsenite-oxidizing Pseudomonas putida strain OS-5, whereas arsB, arsH, and arrA were detected in strain OS-19, arsD and arsB were isolated from strain RW-18, and arsR, arsD, and arsB were found in E. coli strain OS-80. The leader gene of arsR, -arsD, was observed in a weak acid position. Thus, for bacteria exposed to weak acidity, the ars system may cause changes to the ecosystems of As-contaminated mines. Accordingly, the present results suggest that arsR, arsD, arsAB, arsA, arsB, arsC, arsH, arrA, arrB, aoxA, aoxB, aoxC, aoxD, aroA, and aroB may be useful for arsenite-oxidizing bacteria in abandoned arsenic-contaminated mines.
某些废弃矿山的生态系统中含有抗砷细菌，当细菌基因组中存在ars基因时，这些细菌能够进行解毒。ars基因已从恶臭假单胞菌中分离出来，并被鉴定为膜转运调节脱氧核糖核酸家族的成员。在本研究中分离出的亚砷酸盐氧化细菌菌株在66.7 mM砷酸钠（V；Na2HAsO4·7H2O）存在的情况下能够生长，但当亚砷酸钠（III；NaAsO2）浓度高于26 mM时，生长受到抑制。批次实验结果表明，恶臭假单胞菌菌株OS-5在35小时内将1 mM的As(III)完全氧化为As(V)。在亚砷酸盐氧化恶臭假单胞菌菌株OS-5中观察到一个编码膜转运调节蛋白的arsB基因，而在菌株OS-19中检测到arsB、arsH和arrA，从菌株RW-18中分离出arsD和arsB，在大肠杆菌菌株OS-80中发现arsR、arsD和arsB。arsR、-arsD的前导基因在弱酸位置被观察到。因此，对于暴露于弱酸性环境的细菌，ars系统可能会导致砷污染矿山生态系统发生变化。相应地，目前的结果表明，arsR、arsD、arsAB、arsA、arsB、arsC、arsH、arrA、arrB、aoxA、aoxB、aoxC、aoxD、aroA和aroB可能对废弃砷污染矿山中的亚砷酸盐氧化细菌有用。
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