微生物耐砷机理及其在砷地球化学循环中的作用

Arsenic resistance mechanisms in microbes and their roles in arsenic geochemical cycling -A review

摘要:

砷是一种无处不在的有毒类金属,其强致癌性引起了人类的广泛关注。在自然环境中,砷的转化存在物理化学过程和生物过程,其中微生物介导的砷转化是环境砷行为的主要影响因素。微生物的耐砷特性与砷吸收、氧化还原、甲基化、区隔化和外排等过程密切相关。砷在微生物体内的转运转化主要与砷解毒有关,但某些微生物可利用氧化还原过程产生的能量以维持其生长需求。本文综述了微生物介导的砷吸收、转化、区隔化和外排机制,这对阐明砷的地球化学循环过程及指导砷污染土壤和水体修复、阻控农作物砷吸收等方面具有重要意义。

Abstract:

As a ubiquitous metalloid in the environment, arsenic (As) has attracted concerns by humans due to its strong carcinogenic property. Environmental As fate is often affected by physico-chemical and biological factors, of which microbe-mediated arsenic transformation predominates. Arsenic uptake, redox, methylation, sequestration and efflux have been verified to be involved in As resistance in microbes. In some microbes, As transformation contributes to detoxification, while some can obtain the energy for their growth and reproduction from this process. Here we reviewed the mechanisms of microbe-mediated As uptake, transformation, sequestration and efflux, which may help elucidate As geochemical cycling and provide the methods to remediate As-contaminated soils and waters, and to reduce As uptake by crops.