Selective serotonin reuptake inhibitor (SSRI) antidepressants are of increasing concern worldwide due to their ubiquitous occurrence and detrimental effects on aquatic organisms. However, little is known regarding their effects on the dominant bloom-forming cyanobacterium, . Here, we investigated the individual and joint effects of two typical SSRIs fluoxetine (FLX) and sertraline (SER) on at physio-biochemical and molecular levels. Results showed that FLX and SER had strong growth inhibitory effects on with the 96-h median effect concentrations (ECs) of 362 and 225 μg/L, respectively. Besides, the mixtures showed an additive effect on microalgal growth. Meanwhile, both individual SSRIs and their mixtures can inhibit photosynthetic pigment synthesis, cause oxidative damage, destroy cell membrane, and promote microcystin−leucine−arginine (MC-LR) synthesis and release. Moreover, the mixtures enhanced the damage to photosynthesis, antioxidant system, and cell membrane and facilitated MC-LR synthesis and release compared to individuals. Furthermore, transcriptomic analysis revealed that the dysregulation of the key genes related to transport, photosystem, protein synthesis, and non-ribosomal peptide structures was the fundamental molecular mechanism underlying the physio-biochemical responses of . These findings provide a better understanding of the toxicity mechanisms of SSRIs to microalgae and their risks to aquatic ecosystems.

中文翻译：

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综合生理生化和转录组分析揭示两种典型抗抑郁药氟西汀和舍曲林对铜绿微囊藻的联合毒性机制

选择性血清素再摄取抑制剂 (SSRI) 抗抑郁药因其普遍存在以及对水生生物的有害影响而受到全世界越来越多的关注。然而，人们对它们对占优势的水华形成蓝细菌的影响知之甚少。在这里，我们研究了两种典型 SSRIs 氟西汀 (FLX) 和舍曲林 (SER) 在生理生化和分子水平上的个体和联合作用。结果表明，FLX和SER具有较强的生长抑制作用，96小时中位效应浓度（EC）分别为362和225 μg/L。此外，混合物对微藻生长表现出累加效应。同时，单独的SSRIs及其混合物均可抑制光合色素合成，引起氧化损伤，破坏细胞膜，促进微囊藻毒素-亮氨酸-精氨酸（MC-LR）的合成和释放。此外，与个体相比，混合物增强了对光合作用、抗氧化系统和细胞膜的损伤，并促进了MC-LR的合成和释放。此外，转录组分析表明，与运输、光系统、蛋白质合成和非核糖体肽结构相关的关键基因的失调是理化反应的基本分子机制。这些发现有助于更好地了解 SSRIs 对微藻的毒性机制及其对水生生态系统的风险。