Komazec Bruno, Vitko Sandra, Balen Biljana, Cindrić Mario, Biba Renata, Peharec Štefanić Petra
Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia.
Ruđer Bošković Institute, POB 1016, HR-10000 Zagreb, Croatia.
Toxics. 2025 Jul 26;13(8):627. doi: 10.3390/toxics13080627.
Due to widespread use of silver nanoparticles (AgNPs), the assessment of their potential harm to microalgal photosynthesis is crucial, as microalgae, together with cyanobacteria, contribute to approximately 50% of global oxygen production. This study investigated photosynthetic pigments, photosynthetic rate, chlorophyll fluorescence, and the expression of photosynthesis-related genes and proteins in green alga after 72 h exposure to citrate- and cetyltrimethylammonium bromide (CTAB)-stabilized AgNPs, as well as silver ions (AgNO), at concentrations allowing 75% cell survival (EC). All treatments impaired photosynthetic performance. The most pronounced decreases in chlorophyll fluorescence parameters and photosynthetic rate, alongside elevated energy dissipation, were observed after exposure to AgNP-CTAB and AgNO. AgNP-citrate had milder effects and induced compensatory responses, reflected in an increased performance index and upregulation of photosynthesis-related proteins. AgNP-CTAB induced the strongest downregulation of gene and protein expression, likely due to its higher EC concentration and cationic surface promoting interaction with photosynthetic structures. Although AgNO caused fewer molecular changes, it significantly disrupted photosynthetic function, suggesting a direct effect of Ag ions on photosynthesis-related proteins. Overall, the results highlight the role of AgNPs' surface coatings and dosage in determining their phytotoxicity, with photosystem disruption and oxidative stress emerging as key mechanisms of action.
由于银纳米颗粒（AgNPs）的广泛使用，评估其对微藻光合作用的潜在危害至关重要，因为微藻与蓝细菌一起贡献了全球约50%的氧气产量。本研究调查了绿藻在暴露于柠檬酸盐和十六烷基三甲基溴化铵（CTAB）稳定的AgNPs以及银离子（AgNO₃）72小时后，光合色素、光合速率、叶绿素荧光以及光合作用相关基因和蛋白质的表达情况，浓度设定为允许75%细胞存活（EC₇₅）。所有处理均损害了光合性能。在暴露于AgNP-CTAB和AgNO₃后，观察到叶绿素荧光参数和光合速率最显著下降，同时能量耗散增加。柠檬酸盐稳定的AgNP（AgNP-柠檬酸盐）影响较温和并诱导了补偿反应，表现为性能指数增加和光合作用相关蛋白质上调。AgNP-CTAB诱导基因和蛋白质表达的下调最强，可能是由于其较高的EC₇₅浓度以及阳离子表面促进了与光合结构的相互作用。尽管AgNO₃引起的分子变化较少，但它显著破坏了光合功能，表明银离子对光合作用相关蛋白质有直接影响。总体而言，结果突出了AgNPs表面涂层和剂量在决定其植物毒性方面的作用，光系统破坏和氧化应激成为关键作用机制。
