全氟辛烷磺酸钾(PFOS)和纳米氧化锌(Nano-ZnO)单独与联合暴露对斑马鱼胚胎的氧化损伤和细胞凋亡的影响

探讨全氟辛烷磺酸钾(PFOS)和纳米氧化锌(Nano-Zn O)复合暴露对斑马鱼机体氧化损伤和细胞凋亡的影响。将斑马鱼胚胎暴露于PFOS(0、0.4、0.8和1.6 mg·L-1)、Nano-Zn O(0、12.5、25和50 mg·L-1)、PFOS+Nano-Zn O(0、0.4+12.5、0.8+25和1.6+50 mg·L-1)溶液中6天后,检测相关的酶活性变化(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(Gpx)、脂质过氧化物(MDA)、半胱氨酸蛋白酶(Caspase-3和Caspase-9)和与细胞凋亡相关基因(Bax,p53和Bcl-2)表达情况。结果表明:PFOS和Nano-Zn O单独与复合暴露均可造成斑马鱼胚胎的氧化损伤和细胞凋亡,但复合暴露组的氧化损伤和细胞凋亡程度明显大于单独暴露组。在PFOS和Nano-Zn O单独和复合暴露组中,随着处理浓度的升高,SOD、Gpx、Caspase-3和Caspase-9酶的活性显著升高。而CAT酶活性随着处理浓度的升高抑制作用显著。PFOS与Nano-Zn O复合暴露组与单独暴露组相比,Bax和p53表达显著上调,而Bcl-2表达显著下调。因此,在实验浓度范围内,等毒性配比1:1条件下,推测NanoZn O可以增强PFOS对斑马鱼胚胎的氧化损伤和细胞凋亡毒性。     

ZnO-NPs对好氧反硝化细菌Zobellella sp. B307的致毒机制

本文以一株筛自胶州湾沉积物中的好氧反硝化细菌Zobellella sp.B307为研究对象，在短期暴露条件下，通过细菌的生长、脱氮能力，相关酶活以及代谢途径等指标的变化，研究纳米氧化锌（ZnO-NPs）对该菌株的毒性效应；结合锌离子溶出试验、CAT和ROS等氧化应激水平测定，探讨ZnO-NPs对该菌株的致毒机制.结果表明，200mg/L的ZnO-NPs会使菌株硝酸盐氮去除率降至57.53%，LDH升高至对照组的378%，ROS水平高达对照组的5.34倍，SOD活性比对照组升高了60.32%，NIR活性仅为对照组的14.46%；ZnO-NPs主要通过诱导菌株活性氧的生成使其膜通透性改变、相关酶活性下降，并使相关蛋白质、氨基酸的合成及基因表达等代谢通路受到影响，进而抑制该菌株的反硝化能力；游离锌离子的产生可能不是ZnO-NPs对菌株的主要致毒途径.     

ZnO纳米颗粒对SBR活性污泥活性的影响

建立了模拟的SBR反应器,并研究了ZnO纳米颗粒(ZnO-NPs)对SBR活性污泥活性的影响.结果表明低浓度(10mg/L)ZnO-NPs对活性污泥活性无明显抑制作用.较高浓度下,ZnO-NPs对活性污泥沉降性能?呼吸速率?EPS和SMP产量及其组成?有机物降解效率等具有明显影响.20,50,100mg/L ZnO-NPs使COD去除率分别降低8.1%, 19.5%和27.7%,使污泥沉降性能分别降低24.2%,35.0%和36.0%,使MLVSS/MLSS比值分别降低8.0%,14.7%和21%,使活性污泥呼吸速率抑制率达到54.0%, 79.0%和80.3%;使EPS产量分别降低29.0%,49.9%和65.4%,使SMP产量分别升高48.9%,102.6%和203.0%.研究表明,较高浓度ZnO-NPs能够抑制污泥代谢,降低活性污泥生物量,显著抑制活性污泥活性.     

Ecotoxicological effect of zinc oxide nanoparticles on soil microorganisms

The widespread production and use of zinc oxide nanoparticles (ZnO-NPs) in recent years have posed potential threat to the ecosystem. This study aimed to investigate the ecotoxicological effect of ZnO-NPs on soil microorganisms using laboratory microcosm test. Respiration, ammonification, dehydrogenase (DH) activity, and fluorescent diacetate hydrolase (FDAH) activity were used as ecotoxicological parameters. The results showed that in the neutral soil treated with 1 mg ZnO-NPs per g soil (fresh, neutral), ammonification was significantly inhibited during the study period of three months, but the inhibition rate decreased over increasing time. Inhibition in respiration was observed in the first month of the test. In various ZnO-NPs treatments (1 mg, 5 mg, and 10 mg ZnO-NPs per g soil), DH activity and FDAH activity were inhibited during the study period of one month. For both enzyme activities, there were positive dose–response relationships between the concentration of ZnO-NPs and the inhibition rates, but the curves changed over time due to changes of ZnO-NPs toxicity. Soil type affected the toxicity of ZnO-NPs in soil. The toxicity was highest in the acid soil, followed by the neutral soil. The toxicity was relatively low in the alkaline soil. The toxicity was not accounted for by the Zn²⁺ released from the ZnO-NPs. Direct interaction of ZnO-NPs with biologic targets might be one of the reasons. The adverse effect of ZnO-NPs on soil microorganisms in neutral and acid soils is worthy of attention.