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Abstract：
Up to now, complicated organoarsenicals were mainly identified in marine organisms, suggesting that these organisms play a critical role in arsenic biogeochemical cycling because of low phosphate and relatively high arsenic concentration in the marine environment. However, the response of marine macroalgae to inorganic arsenic remains unknown. In this study, Pyropia haitanensis were exposed to arsenate [As(V)] (0.1, 1, 10, 100 μM) or arsenite [As(III)] (0.1, 1, 10 μM) under laboratory conditions for 3 d. The species of water-soluble arsenic, the total concentration of lipid-soluble and cell residue arsenic of the algae cells was analyzed. As(V) was mainly transformed into oxo-arsenosugar-phosphate, with other arsenic compounds such as monomethylated, As(III), demethylated arsenic and oxo-arsenosugar-glycerol being likely the intermediates of arsenosugar synthesis. When high concentration of As(III) was toxic to P. haitanensis, As(III) entered into the cells and was transformed into less toxic organoarsenicals and As(V). Transcriptome results showed genes involved in DNA replication, mismatch repair, base excision repair, and nucleotide excision repair were up-regulated in the algae cells exposed to 10 μM As(V), and multiple genes involved in glutathione metabolism and photosynthetic were up-regulated by 1 μM As(III). A large number of ABC transporters were down-regulated by As(V) while ten genes related to ABC transporters were up-regulated by As(III), indicating that ABC transporters were involved in transporting As(III) to vacuoles in algae cells. These results indicated that P. haitanensis detoxifies inorganic arsenic via transforming them into organoarsenicals and enhancing the isolation of highly toxic As(III) in vacuoles.
摘要：
到目前为止,复杂的有机砷主要在海洋生物中鉴定，表明这些生物在砷生物地球化学循环中起着关键作用，因为海洋环境中磷酸盐含量低，砷浓度相对较高。然而,海洋大型藻类对无机砷的反应仍然未知。在这项研究中,在实验室条件下暴露于砷酸盐[As（V）]（0.1、1、10、100μM）或亚砷酸盐[As（III）]（0.1、1、10μM）3天。水溶性砷，分析了藻类细胞的脂溶性和细胞残留砷的总浓度。As(V)主要转化为氧-砷糖-磷酸,与其他砷化合物如单甲基化，As(III),脱甲基砷和氧代砷糖-甘油可能是砷糖合成的中间体。当高浓度的As（III）对海丹有毒性时，As（III）进入细胞并转化为毒性较小的有机砷和As（V）。转录组结果显示参与DNA复制的基因,失配修复,基底切除修复,在暴露于10μMAs（V）的藻类细胞中，核苷酸切除修复上调，参与谷胱甘肽代谢和光合作用的多个基因被1μMAs（III）上调。As(V)下调了大量ABC转运体,As(III)上调了10个与ABC转运体相关的基因,表明ABC转运蛋白参与将As（III）转运到藻类细胞的液泡中。这些结果表明，海丹生通过将无机砷转化为有机砷并增强液泡中高毒性As（III）的分离来解毒。
