Key message

AgNPs caused significant toxicity and induced oxidative stress in the microalga N. oculata. Also, the interaction between AgNPs and algae led to cell membrane damage.

Abstract

Silver nanoparticles (AgNPs) have been broadly applied in several industrial sectors, and thus inevitably released into the aquatic environments. In the present study, the effect of various concentrations of AgNPs (up to 50 mg/L) on the microalga Nannochloropsis oculata (N. oculata) was investigated. The obtained results showed that half maximal effective concentration (EC₅₀) of AgNPs for the microalga was 20.88 mg/L. Also, the different applied concentrations of AgNPs inhibited the cell growth as well as the photosynthetic machinery and stimulated the production of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂). AgNP treatments dramatically enhanced the content of carotenoids in the treated algae, while they significantly reduced the quantity of phenolic compounds. Furthermore, AgNPs increased the enzymatic activity of catalase (CAT), ascorbate peroxidase (APX) and lactate dehydrogenase (LDH), while they considerably decreased the activity of polyphenol oxidase (PPO) compared to the control sample. Gas chromatography–mass spectrometry (GC–MS) examination demonstrated that after exposure of N. oculata cells to AgNPs, the amounts of saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) were raised, while the levels of monounsaturated fatty acids (MUFAs) were lessened. The Fourier transform infrared spectroscopy (FTIR) results and the microscopic images revealed the interaction of AgNPs with the cells of N. oculata.

中文翻译：

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银纳米颗粒对拟南芥生长，脂肪酸谱和抗氧化反应的影响

关键信息

AgNPs在微藻N. oculata中引起明显的毒性并引起氧化应激。同样，AgNP和藻类之间的相互作用导致细胞膜受损。

抽象

银纳米颗粒（AgNPs）已广泛应用于多个工业领域，因此不可避免地释放到水生环境中。在本研究中，研究了不同浓度的AgNPs（最高50 mg / L）对微藻Nannochloropsis oculata（N. oculata）的影响。获得的结果表明，微藻的AgNP最大有效浓度的一半（EC ₅₀）为20.88 mg / L。同样，不同浓度的AgNPs会抑制细胞生长以及光合作用机制，并刺激丙二醛（MDA）和过氧化氢（H ₂ O _{2）的产生。}）。AgNP处理显着提高了处理过的藻类中类胡萝卜素的含量，同时显着减少了酚类化合物的量。此外，AgNPs增加了过氧化氢酶（CAT），抗坏血酸过氧化物酶（APX）和乳酸脱氢酶（LDH）的酶活性，而与对照样品相比，它们大大降低了多酚氧化酶（PPO）的活性。气相色谱-质谱（GC-MS）检查表明，暴露于眼球菌后细胞到AgNPs时，饱和脂肪酸（SFAs）和多不饱和脂肪酸（PUFAs）的量增加，而单不饱和脂肪酸（MUFAs）的水平降低。傅里叶变换红外光谱（FTIR）结果和显微图像揭示了AgNPs与眼球猪笼草细胞的相互作用。