Ofloxacin (OFL), one of the most widely used fluoroquinolone antibiotics, has been frequently detected in marine environments. Nonetheless, researchers are yet to focus on the effects of OFL on the benthos. In the present study, marine clams (Ruditapes philippinarum) were exposed to OFL (0.5, 50, and 500 μg/L) for 14 d, followed by a 7 d depuration period. The accumulation of OFL, antioxidative defense responses, neurotoxicity, burrowing behavior, and metabolomic changes in clams were evaluated. The results indicated that OFL could accumulate in clams, albeit with a low bioaccumulation capacity. The intermediate (50 μg/L) and high (500 μg/L) levels of OFL induced significant antioxidative responses in the gills and digestive glands of clams, mainly manifesting as the inhibition of catalase activities and the induction of superoxide dismutase and glutathione S-transferase activities, which ultimately elevated the content of malondialdehyde, causing oxidative damage. Furthermore, the significant induction of acetylcholinesterase activities was observed, coinciding with a significant increase in burrowing rates of clams. The high level of OFL affected glycerophospholipid, arachidonic acid, steroid hormone biosynthesis, unsaturated fatty acids biosynthesis, and glycolysis/glycogenesis metabolism. In conclusion, this study has contributed to the understanding of the physiological and biochemical effects and molecular toxicity mechanisms of OFL to marine bivalves.

中文翻译：

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受氧氟沙星暴露干扰的蛤蜊 （Ruditapes philippinarum） 的代谢变化和氧化应激反应


氧氟沙星 （OFL） 是使用最广泛的氟喹诺酮类抗生素之一，经常在海洋环境中检测到。尽管如此，研究人员尚未关注 OFL 对底栖生物的影响。在本研究中，海蛤蜊 （Ruditapes philippinarum） 暴露于 OFL （0.5、50 和 500 μg/L） 14 d，然后是 7 d 的净化期。评价蛤蜊 OFL 的积累、抗氧化防御反应、神经毒性、穴居行为和代谢组学变化。结果表明，OFL 可以在蛤蜊中积累，尽管生物积累能力较低。中度 （50 μg/L） 和高浓度 （500 μg/L） 的 OFL 诱导蛤蜊鳃和消化腺出现显著的抗氧化反应，主要表现为过氧化氢酶活性的抑制和超氧化物歧化酶和谷胱甘肽 S-转移酶活性的诱导，最终提高丙二醛含量，引起氧化损伤。此外，观察到乙酰胆碱酯酶活性的显着诱导，与蛤蜊穴居率的显着增加相吻合。高水平的 OFL 影响甘油磷脂、花生四烯酸、类固醇激素生物合成、不饱和脂肪酸生物合成和糖酵解/糖生成代谢。总之，本研究有助于理解 OFL 对海洋双壳类的生理生化效应和分子毒性机制。