Detection, diversity and expression of aerobic bacterial arsenite oxidase genes
Detection, diversity and expression of aerobic bacterial arsenite oxidase genes
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DOI：
10.1111/j.1462-2920.2006.01215.x
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发表时间：
2007-04-01
影响因子：
5.1
通讯作者：
Santini, Joanne M.
中科院分区：
文献类型：
--
作者：
Inskeep, William P.;Macur, Richard E.;Santini, Joanne M.
南亚和东南亚的砷 (As) 饮用水危机激发了人们对土壤-水系统中控制砷氧化还原循环的微生物过程的深入研究。亚砷酸盐的微生物氧化是全球砷循环中的关键环节，并且已经从各种水生和土壤环境中分离出了系统发育多样化的亚砷酸盐氧化微生物。然而，尽管在各种纯培养物中砷的代谢特征方面取得了进展，但尚未开发出功能基因方法来确定亚砷酸盐氧化基因在土壤-水-沉积物系统中的重要性和分布。在这里，我们首次报道从已知亚砷酸盐被氧化的各种土壤沉积物和地热环境中成功扩增亚砷酸盐氧化酶样基因（aroA/asoA/aoxB）。在目前的工作之前，GenBank 中只有 16 个 aroA/asoA/aoxB 样基因序列，其中大多数是全基因组同源性搜索的推定分配。尽管 aroA/asoA/aoxB 基因序列在不同的门中并不是高度保守的，但简并引物已成功地用于表征来自 10 个地理上孤立的砷污染位点和 13 个亚砷酸盐氧化生物体的 160 多个不同的 aroA 样序列。引物组还可用于确认亚砷酸盐氧化生物体和亚砷酸盐氧化成砷酸盐的地热环境中 aroA 样基因的表达。本研究获得的aroA样序列的系统发育和生态多样性表明，好氧亚砷酸盐氧化基因广泛分布在细菌领域，广泛存在于含砷的土壤-水系统中，并在砷的生物地球化学循环中发挥着关键作用。
The arsenic (As) drinking water crisis in south and south-east Asia has stimulated intense study of the microbial processes controlling the redox cycling of As in soil-water systems. Microbial oxidation of arsenite is a critical link in the global As cycle, and phylogenetically diverse arsenite-oxidizing microorganisms have been isolated from various aquatic and soil environments. However, despite progress characterizing the metabolism of As in various pure cultures, no functional gene approaches have been developed to determine the importance and distribution of arsenite-oxidizing genes in soil-water-sediment systems. Here we report for the first time the successful amplification of arsenite oxidase-like genes (aroA/asoA/aoxB) from a variety of soil-sediment and geothermal environments where arsenite is known to be oxidized. Prior to the current work, only 16 aroA/asoA/aoxB-like gene sequences were available in GenBank, most of these being putative assignments from homology searches of whole genomes. Although aroA/asoA/aoxB gene sequences are not highly conserved across disparate phyla, degenerate primers were used successfully to characterize over 160 diverse aroA-like sequences from 10 geographically isolated, arsenic-contaminated sites and from 13 arsenite-oxidizing organisms. The primer sets were also useful for confirming the expression of aroA-like genes in an arsenite-oxidizing organism and in geothermal environments where arsenite is oxidized to arsenate. The phylogenetic and ecological diversity of aroA-like sequences obtained from this study suggests that genes for aerobic arsenite oxidation are widely distributed in the bacterial domain, are widespread in soil-water systems containing As, and play a critical role in the biogeochemical cycling of As.