College of Resources and Environmental Science, Hunan Normal University, Hunan 410081, China.
Environ Sci Technol. 2012 Oct 16;46(20):11259-66. doi: 10.1021/es300454b. Epub 2012 Oct 4.
Microbes play an important role in arsenic transformation and cycling in the environment. Microbial arsenic oxidation and reduction were demonstrated in the growth media of arsenic hyperaccumulator Pteris vittata L. All arsenite (AsIII) at 0.1 mM in the media was oxidized after 48 h incubation. Oxidation was largely inhibited by antibiotics, indicating that bacteria played a dominant role. To identify AsIII oxidizing bacteria, degenerate primers were used to amplify ∼500 bp of the AsIII oxidase gene aioA (aroA) using DNA extracted from the media. One aioA (aroA)-like sequence (MG-1, tentatively identified as Acinetobacter sp.) was amplified, exhibiting 82% and 91% identity in terms of gene and deduced protein sequence to those from Acinetobacter sp. 33. In addition, four bacterial strains with different arsenic tolerance were isolated and identified as Comamonas sp.C-1, Flavobacterium sp. C-2, Staphylococcus sp. C-3, and Pseudomonas sp. C-4 using carbon utilization, fatty acid profiles, and/or sequencing 16s rRNA gene. These isolates exhibited dual capacity for both AsV reduction and AsIII oxidation under ambient conditions. Arsenic-resistant bacteria with strong AsIII oxidizing ability may have potential to improve bioremediation of AsIII-contaminated water using P. vittata and/or other biochemical strategies.
微生物在环境中砷的转化和循环中起着重要作用。在砷超富集植物蜈蚣草的生长培养基中证明了微生物砷的氧化和还原作用。在培养基中，所有 0.1mM 的亚砷酸盐（AsIII）在 48 小时孵育后都被氧化。氧化作用被抗生素强烈抑制，表明细菌起主要作用。为了鉴定 AsIII 氧化细菌，使用了简并引物，从培养基中提取的 DNA 扩增了约 500bp 的 AsIII 氧化酶基因 aioA（aroA）。扩增出一个 aioA（aroA）类似序列（MG-1，暂定鉴定为不动杆菌属），其基因和推导的蛋白序列与不动杆菌属 33 号的同源性分别为 82%和 91%。此外，还分离并鉴定了 4 株具有不同砷耐受性的细菌，分别为 Comamonas sp.C-1、Flavobacterium sp. C-2、Staphylococcus sp. C-3 和 Pseudomonas sp. C-4，使用碳利用、脂肪酸图谱和/或测序 16s rRNA 基因。这些分离株在环境条件下同时具有 AsV 还原和 AsIII 氧化的双重能力。具有强 AsIII 氧化能力的砷抗性细菌可能有潜力利用蜈蚣草和/或其他生化策略来改善砷污染水的生物修复。
