Nanocolloids (Ncs) are ubiquitous in natural surface waters. However, the effects of Ncs on the fate and ecotoxicity of graphene oxide (GO, a popular engineered nanomaterial (ENM)) remain largely unknown. Ncs exhibit strong adsorption affinity (KL = 1.93 L/mg) and high adsorption capacity (176.2 mg/g) for GO. After Ncs hybridization, GO nanosheets became scrolls, and the aggregation rate of GO decreased. The influence of humic acid and Ncs on GO toxicity was compared. Humic acid mitigated the phytotoxicity of GO. However, GO and GO-Ncs were found to have an envelopment effect on algal cells, and both could enter algal cells. GO-Ncs induced higher reactive oxygen species (ROS) generation, stronger DNA damage and plasmolysis, and more obvious inhibition of photosynthesis compared to GO. Proteomic analysis revealed that photosystem I- and II-related proteins (e.g., E1ZQR2 and E1ZPG5) were regulated more significantly in the GO-Ncs groups than in the GO groups. A combined proteomic and metabolomic analysis showed that inhibition of carbohydrate, fatty acid, and amino acid metabolism contributed to ROS generation. Given the high concentrations and activity of Ncs, the above results highlight the need for reconsideration of the Ncs-mediated environmental behaviors and risks of ENMs and other pollutants.

中文翻译：

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天然纳米胶体介导氧化石墨烯的植物毒性。

纳米胶体（Ncs）在自然地表水中无处不在。然而，Ncs对氧化石墨烯（GO，一种流行的工程纳米材料（ENM））的命运和生态毒性的影响仍然未知。Ncs对GO具有很强的吸附亲和力（KL = 1.93 L / mg）和高吸附能力（176.2 mg / g）。Ncs杂交后，GO纳米片变成卷状，GO的聚集速率降低。比较了腐殖酸和Ncs对GO毒性的影响。腐殖酸减轻了GO的植物毒性。然而，发现GO和GO-Ncs对藻类细胞有包膜作用，并且两者都可以进入藻类细胞。与GO相比，GO-Ncs诱导了更高的活性氧（ROS）生成，更强的DNA损伤和溶酶作用，以及对光合作用的更明显抑制。蛋白质组学分析表明，GO-Ncs组的光系统I和II相关蛋白（例如，E1ZQR2和E1ZPG5）受调节程度高于GO组。蛋白质组学和代谢组学的组合分析表明，抑制碳水化合物，脂肪酸和氨基酸代谢可促进ROS的产生。鉴于Ncs的高浓度和活性，以上结果突出表明需要重新考虑Ncs介导的环境行为以及ENM和其他污染物的风险。