College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China; National Engineering Research Center of Coal Mine Water Hazard Controlling (Suzhou University), Suzhou, Anhui, 234000, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
National Engineering Research Center of Coal Mine Water Hazard Controlling (Suzhou University), Suzhou, Anhui, 234000, China.
Environ Pollut. 2019 Sep;252(Pt B):1755-1763. doi: 10.1016/j.envpol.2019.06.126. Epub 2019 Jul 3.
Only limited information is available on the effects of dissolved organic phosphorus (DOP) on arsenate (As(V)) bioaccumulation and biotransformation in organisms. In this study, we examined the influence of three different DOP forms (β-sodium glycerophosphate (βP), adenosine 5'-triphosphate (ATP), and D-Glucose-6-phosphate disodium (GP) salts) and inorganic phosphate (IP) on As(V) toxicity, accumulation, and biotransformation in Microcystis aeruginosa. Results showed that M. aeruginosa utilized the three DOP forms to sustain its growth. At a subcellular level, the higher phosphorus (P) distribution in metal-sensitive fractions (MSF) observed in the IP treatments could explain the comparatively lower toxic stress of algae compared to the DOP treatments. Meanwhile, the higher MSF distribution of arsenic (As) in M. aeruginosa in the presence of DOP could explain the higher toxicity with lower 96-h half maximal effective concentration (EC) values. Although we observed As(V) and P discrimination in M. aeruginosa under IP treatments with high intracellular P/As, we did not find this discrimination under the DOP treatments. As accumulation in algal cells was therefore greatly enhanced by DOP, especially βP, given its lower transformation rate to phosphate compared to ATP and GP in media. Additionally, As(V) reduction and, subsequently, As(III) methylation were greatly facilitated in M. aeruginosa by the presence of DOP, particularly GP, which was confirmed by the higher relative expression of its two functional genes (arsC and arsM). Our findings indicate that As(V) accumulation and its subsequent biotransformation were enhanced by organic P forms, which provides new insight into how DOP modulates As metabolism in algae.
关于溶解态有机磷（DOP）对生物体中砷酸盐（As(V)）生物积累和生物转化的影响，目前仅有有限的信息。在这项研究中，我们研究了三种不同的 DOP 形式（β-甘油磷酸钠（βP）、腺苷 5'-三磷酸（ATP）和 D-葡萄糖-6-磷酸二钠盐（GP）盐）和无机磷（IP）对铜绿微囊藻（M. aeruginosa）中 As(V)毒性、积累和生物转化的影响。结果表明，铜绿微囊藻利用这三种 DOP 形式来维持其生长。在亚细胞水平上，在 IP 处理中观察到金属敏感部分（MSF）中更高的磷（P）分布，可以解释藻类受到的毒性压力相对较低，而不是 DOP 处理。同时，在 DOP 存在的情况下，铜绿微囊藻中更高的砷（As）在 MSF 中的分布可以解释毒性较高而 96 小时半数最大有效浓度（EC）值较低的原因。虽然我们在 IP 处理中观察到了藻类细胞内高 P/As 条件下对 As(V)和 P 的区分，但在 DOP 处理中没有发现这种区分。因此，DOP 极大地促进了 As 积累，特别是 βP，因为与 ATP 和 GP 相比，其在介质中的转化率较低。此外，DOP，特别是 GP 的存在极大地促进了 As(V)的还原，随后促进了 As(III)的甲基化，这通过其两个功能基因（arsC 和 arsM）的相对表达较高得到了证实。我们的研究结果表明，有机磷形式促进了 As(V)的积累及其随后的生物转化，这为 DOP 如何调节藻类中 As 代谢提供了新的见解。
