Co-Innovation Center for Sustainable Forestry in Southern China, College of Ecology and Environment, Nanjing Forestry University, No. 159 Longpan Road, Nanjing, Jiangsu, 210037, China; School of Chemical Engineering and Materials, Changzhou Institute of Technology, No. 666 Liaohe Road, Changzhou, Jiangsu, 213032, China.
Co-Innovation Center for Sustainable Forestry in Southern China, College of Ecology and Environment, Nanjing Forestry University, No. 159 Longpan Road, Nanjing, Jiangsu, 210037, China.
Environ Pollut. 2024 Nov 15;361:124887. doi: 10.1016/j.envpol.2024.124887. Epub 2024 Sep 3.
Emerging pollutants such as antibiotics have aroused great concern in recent years. However, the knowledge of low concentration-induced hormesis was not well understood. This study evaluated and quantified hormetic effects of ofloxacin on Chlorella pyrenoidosa. LogNormal model predicted the maximal non-effect concentration was 0.13 mg/L and 2.96 mg/L at 3 and 21 d, respectively. The sensitive alterations in chlorophyll fluorescence suggested PSII was the main target. Transcriptomics revealed ofloxacin inhibited genes related to photosynthetic system while the cyclic electron around PSI decreased the pH value in stroma side and stimulated photoprotection via up-regulating psbS. The stimulation in citrate cycle pathway met the urgent requirements of energy for DNA replication and repair. In addition, the negative feedback of G3P in glycolysis pathway inhibited Calvin cycle. The degradation products illustrated the occurrence of multiple detoxification mechanisms such as demethylation and ring-opening. The mobilization of cytochrome P450 generated the constant detoxication of ofloxacin while glutathione was consumptively involved in biological binding. This study provided new insights into the molecular mechanisms of antibiotic-induced hormesis in microalgae.
新兴污染物如抗生素近年来引起了极大关注。然而，低浓度诱导的激素效应的知识还没有被很好地理解。本研究评估和量化了氧氟沙星对栅藻的激素效应。对数正态模型预测最大无效应浓度分别为 0.13mg/L 和 2.96mg/L，分别在 3d 和 21d。叶绿素荧光的敏感变化表明 PSII 是主要靶标。转录组学揭示，氧氟沙星抑制与光合作用系统相关的基因，而 PSI 周围的循环电子降低了基质侧的 pH 值，并通过上调 psbS 刺激光保护。柠檬酸循环途径的刺激满足了 DNA 复制和修复所需的能量的迫切需求。此外，糖酵解途径中 G3P 的负反馈抑制卡尔文循环。降解产物表明发生了多种解毒机制，如脱甲基和开环。细胞色素 P450 的动员导致氧氟沙星的持续解毒，而谷胱甘肽则消耗性地参与生物结合。本研究为抗生素诱导微藻激素效应的分子机制提供了新的见解。
