Identification of genes conferring arsenic resistance to Escherichia coli from an effluent treatment plant sludge metagenomic library
Identification of genes conferring arsenic resistance to Escherichia coli from an effluent treatment plant sludge metagenomic library
复制标题
DOI：
10.1111/j.1574-6941.2008.00613.x
复制
发表时间：
2009-01-01
影响因子：
4.2
通讯作者：
Sharma, Rakesh
中科院分区：
文献类型：
--
作者：
Chauhan, Nar Singh;Ranjan, Ravi;Sharma, Rakesh
大多数细菌无法在实验室培养。宏基因组方法提供了对整个细菌群落的基因库的培养独立的访问。以某工业污水处理厂污泥为材料，构建了含1.25 Gb微生物群落DNA的宏基因组文库。从宏基因组文库中筛选出2个抗砷克隆。无性系MT3和MT6对砷酸钠的抗性分别比亲本高8倍和18倍。无性系对亚砷酸盐的抗性也增强了，但对锑的抗性没有增强。序列分析揭示了砷酸盐还原酶和亚砷酸盐外排泵的编码基因。从克隆MT6中鉴定出一个新的砷酸盐抗性基因（arsN），该基因编码与乙酰转移酶相似的蛋白。在许多细菌基因组中发现砷同源物与抗砷基因密切相关。在嗜石油甲基lium PM1和脱卤厌氧杆菌2CP-C中发现砷酸盐还原酶与砷酸盐同源物融合，在越南伯克霍尔德菌G4中发现砷酸盐伴侣物。ArsN单独导致野生型大肠杆菌W3110对砷酸钠的抗性提高约6倍。
The majority of bacteria elude culture in the laboratory. A metagenomic approach provides culture-independent access to the gene pool of the whole bacterial community. A metagenomic library was constructed from an industrial effluent treatment plant sludge containing about 1.25 Gb of microbial community DNA. Two arsenic-resistant clones were selected from the metagenomic library. Clones MT3 and MT6 had eight- and 18-fold higher resistance to sodium arsenate in comparison with the parent strain, respectively. The clones also showed increased resistance to arsenite but not to antimony. Sequence analysis of the clones revealed genes encoding for putative arsenate reductases and arsenite efflux pumps. A novel arsenate resistance gene (arsN) encoding a protein with similarity to acetyltransferases was identified from clone MT6. ArsN homologues were found to be closely associated with arsenic resistance genes in many bacterial genomes. ArsN homologues were found fused to putative arsenate reductases in Methylibium petroleiphilum PM1 and Anaeromyxobacter dehalogenans 2CP-C and with a putative arsenite chaperone in Burkholderia vietnamiensis G4. ArsN alone resulted in an approximately sixfold higher resistance to sodium arsenate in wild-type Escherichia coli W3110.