Mechanisms of silver nanoparticle toxicity on the marine cyanobacterium Prochlorococcus under environmentally-relevant conditions
Mechanisms of silver nanoparticle toxicity on the marine cyanobacterium Prochlorococcus under environmentally-relevant conditions
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DOI：
10.1016/j.scitotenv.2020.141229
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发表时间：
2020-12-10
影响因子：
9.8
通讯作者：
Christie-Oleza, Joseph A.
中科院分区：
文献类型：
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作者：
Dedman, Craig J.;Newson, Gabrielle C.;Christie-Oleza, Joseph A.
全球对银纳米颗粒（AgNP）的需求及其不可避免地释放到环境中的需求正在迅速增加。银纳米颗粒显示抗菌特性，以前已记录对海洋浮游植物产生不利影响。然而，生态毒理学的研究往往是妥协的使用非生态相关的条件下，在环境条件下的AgNP毒性的机制仍然不清楚。为了研究银纳米粒子对自然海洋生物群落的影响，自然组合暴露于柠檬酸盐稳定的银纳米粒子。在这里，调查证实，海洋优势蓝藻原绿球藻是特别敏感的AgNP暴露。虽然原绿球藻是地球上最丰富的光合生物，对全球初级生产力有着重要贡献，但对这种蓝藻的生态毒理学研究很少。为了解决这个问题，原绿球藻暴露于柠檬酸盐稳定的银纳米粒子，以及银在其离子形式（硫酸银），在模拟的自然条件下。AgNP和离子银在浓度>= 10 μ g L-1时都能使原绿球藻种群减少90%以上，这代表了环境中预测的AgNP浓度上限（10 μ g L-1）。长期评估显示，这是一种不可逆转的扰动。通过使用超氧化物和过氧化氢的猝灭剂，以及与离子银的孵育，揭示了AgNP毒性可能来自于有毒超氧化物物种生成和离子银浸出的协同效应。毒性的程度强烈依赖于细胞密度，并在细胞密度更高的培养物中完全减轻。因此，颗粒与细胞比率的计算和报告表明，该参数对于实验工作的标准化是有效的，并且允许在细胞密度可能变化的研究之间进行直接比较。鉴于海洋蓝藻在全球初级生产和地球化学循环中发挥的关键作用，它们对AgNP暴露的更高敏感性是污染热点地区的一个问题。(C)2020年，任作家。由爱思唯尔公司出版
Global demand for silver nanoparticles (AgNPs), and their inevitable release into the environment, is rapidly increasing. AgNPs display antimicrobial properties and have previously been recorded to exert adverse effects upon marine phytoplankton. However, ecotoxicological research is often compromised by the use of non-ecologically relevant conditions, and the mechanisms of AgNP toxicity under environmental conditions remains unclear. To examine the impact of AgNPs on natural marine communities, a natural assemblage was exposed to citrate-stabilised AgNPs. Here, investigation confirmed that the marine dominant cyanobacteria Prochlorococcus is particularly sensitive to AgNP exposure. Whilst Prochlorococcus represents themost abundant photosynthetic organism on Earth and contributes significantly to global primary productivity, little ecotoxicological research has been carried out on this cyanobacterium. To address this, Prochlorococcus was exposed to citrate-stabilised AgNPs, as well as silver in its ionic form(Ag2SO4), under simulated natural conditions. Both AgNPs and ionic silver were observed to reduce Prochlorococcus populations by over 90% at concentrations >= 10 mu g L-1, representing the upper limit of AgNP concentrations predicted in the environment (10 mu g L-1). Longer-term assessment revealed this to be a perturbation which was irreversible. Through use of quenching agents for superoxide and hydrogen peroxide, alongside incubations with ionic silver, it was revealed that AgNP toxicity likely arises from synergistic effects of toxic superoxide species generation and leaching of ionic silver. The extent of toxicity was strongly dependent on cell density, and completely mitigated in more cell-dense cultures. Hence, the calculation and reporting of the particle-to-cell ratio reveals that this parameter is effective for standardisation of experimental work, and allows for direct comparison between studies where cell density may vary. Given the key role that marine cyanobacteria play in global primary production and biogeochemical cycling, their higher susceptibility to AgNP exposure is a concern in hotspots of pollution. (C) 2020 The Authors. Published by Elsevier B.V.