Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra , University Drive, Bruce ACT 2601, Australia.
Environ Sci Technol. 2015 Jan 6;49(1):33-50. doi: 10.1021/es504074z. Epub 2014 Dec 18.
This review investigates the arsenic species produced by and found in marine unicellular algae to determine if unicellular algae contribute to the formation of arsenobetaine (AB) in higher marine organisms. A wide variety of arsenic species have been found in marine unicellular algae including inorganic species (mainly arsenate--As(V)), methylated species (mainly dimethylarsenate (DMA)), arsenoribosides (glycerol, phosphate, and sulfate) and metabolites (dimethylarsenoethanol (DMAE)). Subtle differences in arsenic species distributions exist between chlorophyte and heterokontophyte species with As(V) commonly found in water-soluble cell fractions of chlorophyte species, while DMA is more common in heterokontophyte species. Additionally, different arsenoriboside species are found in each phyla with glycerol and phosphate arsenoribosides produced by chlorophytes, whereas glycerol, phosphate, and sulfate arsenoribosides are produced by heterokontophytes, which is similar to existing data for marine macro-algae. Although arsenoribosides are the major arsenic species in many marine unicellular algal species, AB has not been detected in unicellular algae which supports the hypothesis that AB is formed in marine animals via the ingestion and further metabolism of arsenoribosides. The observation of significant DMAE concentrations in some unicellular algal cultures suggests that unicellular algae-based detritus contains arsenic species that can be further metabolized to form AB in higher marine organisms. Future research establishing how environmental variability influences the production of arsenic species by marine unicellular algae and what effect this has on arsenic cycling within marine food webs is essential to clarify the role of these organisms in marine arsenic cycling.
本综述调查了海洋单细胞藻类中产生和存在的砷形态，以确定单细胞藻类是否有助于海洋高等生物中砷甜菜碱（AB）的形成。在海洋单细胞藻类中发现了多种砷形态，包括无机形态（主要是砷酸盐--As(V)）、甲基化形态（主要是二甲基砷酸盐（DMA））、砷核苷（甘油、磷酸盐和硫酸盐）和代谢物（二甲基砷乙氧基乙醇（DMAE））。在绿藻和异鞭毛藻物种之间，砷形态分布存在细微差异，As(V)通常存在于绿藻物种的水溶性细胞部分，而 DMA 则更为常见于异鞭毛藻物种。此外，在每个门中都发现了不同的砷核苷，甘油和磷酸盐砷核苷由绿藻产生，而甘油、磷酸盐和硫酸盐砷核苷由异鞭毛藻产生，这与现有的海洋大型藻类数据相似。尽管砷核苷是许多海洋单细胞藻类物种中的主要砷形态，但在单细胞藻类中未检测到 AB，这支持了 AB 通过海洋动物摄入和进一步代谢砷核苷形成的假说。在一些单细胞藻类培养物中观察到大量 DMAE 浓度表明，基于单细胞藻类的碎屑中含有可进一步代谢形成 AB 的砷形态。未来的研究建立了环境变异性如何影响海洋单细胞藻类产生砷形态以及这对海洋食物网中砷循环的影响，对于阐明这些生物在海洋砷循环中的作用至关重要。
