Humic acid plays an important role in controlling the toxicity of nanoparticles to organisms. However, little is known about the influence of different fractions of dissolved humic acid (DHA) from soil on the toxicity of nanoparticles to organisms. The concentration of γ-Fe2O3 and the exposure time affected the malondialdehyde (MDA) content, reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) activity in P. chrysosporium cells and were inversely proportional to the relative activities of the cells. P. chrysosporium was exposed to γ-Fe2O3 and DHA1 for 3 h, 6 h and 12 h. Catalase (CAT) and peroxidase (POD) activities were generally higher than control. Particularly, under the influence of 50 mg/L DHA1 and different concentrations of γ-Fe2O3 (10 and 50 mg/L), the CAT and POD activities were higher than those of cells exposed to γ-Fe2O3 alone. Conversely, both activities of P. chrysosporium exposed to DHA4 combined with γ-Fe2O3 for 12 h were lower than those of cells exposed to γ-Fe2O3 alone and gradually decreased with increasing DHA4 concentration (0, 10 and 50 mg/L). The μ-XAFS normalized spectrum indicated that Fe3+ entering the cells tended to transform into Fe2+ as the stress time prolonged. TEM analysis confirmed the toxicity of high concentrations of γ-Fe2O3 to P. chrysosporium. The comet assay showed that DHA4 in soil enhanced the toxicity of γ-Fe2O3 to P. chrysosporium more than DHA1 did. Namely, compared to DHA1, DHA4 made it easier for nano-Fe2O3 to enter P. chrysosporium cells, causing more toxicity of γ-Fe2O3 to P. chrysosporium.

中文翻译：

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各种腐殖酸级分与铁纳米颗粒之间的相互作用对白腐真菌毒性的影响。

腐殖酸在控制纳米颗粒对生物体的毒性中起重要作用。但是，关于土壤中不同含量的腐殖酸（DHA）对纳米颗粒对生物体毒性的影响知之甚少。γ-Fe2O3的浓度和暴露时间影响了金孢假单胞菌细胞中丙二醛（MDA）含量，活性氧（ROS）产生和乳酸脱氢酶（LDH）活性，并且与细胞的相对活性成反比。金孢假单胞菌暴露于γ-Fe2O3和DHA1 3小时，6小时和12小时。过氧化氢酶（CAT）和过氧化物酶（POD）活性通常高于对照。特别是在50 mg / L DHA1和不同浓度的γ-Fe2O3（10和50 mg / L）的影响下，CAT和POD活性高于单独暴露于γ-Fe2O3的细胞。相反，暴露于DHA4与γ-Fe2O3结合的金黄色葡萄球菌的两种活性均低于单独暴露于γ-Fe2O3的细胞的活性，并且随着DHA4浓度（0、10和50 mg / L）的增加而逐渐降低。μ-XAFS归一化光谱表明，随着胁迫时间的延长，进入细胞的Fe3 +倾向于转化为Fe2 +。TEM分析证实了高浓度的γ-Fe2O3对金黄色葡萄球菌的毒性。彗星试验表明，土壤中的DHA4比DHA1增强了γ-Fe2O3对金黄色葡萄球菌的毒性。即，与DHA1相比，DHA4使纳米Fe2O3更容易进入金黄色葡萄球菌细胞，引起γ-Fe2O3对金黄色葡萄球菌的更大毒性。暴露于DHA4和γ-Fe2O3混合的金孢菌比单独暴露于γ-Fe2O3的细胞低，并且随着DHA4浓度的增加（0、10和50 mg / L）逐渐降低。μ-XAFS归一化光谱表明，随着胁迫时间的延长，进入细胞的Fe3 +倾向于转化为Fe2 +。TEM分析证实了高浓度的γ-Fe2O3对金黄色葡萄球菌的毒性。彗星试验表明，土壤中的DHA4比DHA1增强了γ-Fe2O3对金黄色葡萄球菌的毒性。即，与DHA1相比，DHA4使纳米Fe2O3更容易进入金黄色葡萄球菌细胞，引起γ-Fe2O3对金黄色葡萄球菌的更大毒性。暴露于DHA4和γ-Fe2O3混合的金孢菌比单独暴露于γ-Fe2O3的细胞低，并且随着DHA4浓度（0、10和50 mg / L）的增加而逐渐降低。μ-XAFS归一化光谱表明，随着胁迫时间的延长，进入细胞的Fe3 +倾向于转化为Fe2 +。TEM分析证实了高浓度的γ-Fe2O3对金黄色葡萄球菌的毒性。彗星试验表明，土壤中的DHA4比DHA1增强了γ-Fe2O3对金黄色葡萄球菌的毒性。即，与DHA1相比，DHA4使纳米Fe2O3更容易进入金黄色葡萄球菌细胞，引起γ-Fe2O3对金黄色葡萄球菌的更大毒性。10和50 mg / L）。μ-XAFS归一化光谱表明，随着胁迫时间的延长，进入细胞的Fe3 +倾向于转化为Fe2 +。TEM分析证实了高浓度的γ-Fe2O3对金黄色葡萄球菌的毒性。彗星试验表明，土壤中的DHA4比DHA1增强了γ-Fe2O3对金黄色葡萄球菌的毒性。即，与DHA1相比，DHA4使纳米Fe2O3更容易进入金黄色葡萄球菌细胞，引起γ-Fe2O3对金黄色葡萄球菌的更大毒性。10和50 mg / L）。μ-XAFS归一化光谱表明，随着胁迫时间的延长，进入细胞的Fe3 +倾向于转化为Fe2 +。TEM分析证实了高浓度的γ-Fe2O3对金黄色葡萄球菌的毒性。彗星试验显示，土壤中的DHA4比DHA1增强了γ-Fe2O3对金黄色葡萄球菌的毒性。即，与DHA1相比，DHA4使纳米Fe2O3更容易进入金黄色葡萄球菌细胞，引起γ-Fe2O3对金黄色葡萄球菌的更大毒性。