College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China.
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China.
Water Res. 2021 Sep 1;202:117448. doi: 10.1016/j.watres.2021.117448. Epub 2021 Jul 20.
Microcystis-dominated cyanobacterial blooms (MCBs) severely threaten ecological health by causing hypoxia and releasing microcystins (MCs). Luteolin has potential as low-cost eco-safe algaecide against Microcystis, but to enhance sustainability of its algicidal effect and elucidate underlying mechanisms at proteomic level are urgently desirable. This study optimally constructed continuous-release microsphere (CRM) of luteolin with strong solidity and durability even after long-term immersion. Applying luteolin CRM, this study developed a long-term algicidal option to strongly inhibit Microcystis growth and MC-release until 49 days, with inhibition ratios of growth and MC-release (both ≥ 98%) and inhibitory effect-lasting time (nearly 50 days) of CRM superior to most former reports, and long-term strong inhibitory effects of CRM on Microcystis growth and MC-release kept stable at various nitrogen levels. Also, luteolin CRM rendered extracellular MCs content decrease to nearby acceptable threshold for drinking water. These signified a promising prospect of luteolin CRM in sustained effective control against toxigenic MCBs in waters of different eutrophic states. Comparative proteomic analysis showed that luteolin CRM significantly up-regulated photosynthesis and protein homestasis, but down-regulated other processes including stress response, MC-synthesis/release, glycolysis, amino acid synthesis, fatty acid synthesis/β-oxidation, tricarboxylic acid cycle, transcription, translation, transport, cell shaping and cell division. These implied that continuous stress of luteolin released from CRM induced Microcystis proteome towards a shift of higher energy storage but lower energy release/consumption, which largely disturbed its physiological metabolic processes and thus negatively impact its growth. Proteomics results shed newly deep insights on algicidal mechanisms of flavonoid in the form of CRM.
微囊藻为主的蓝藻水华（MCBs）通过产生缺氧和释放微囊藻毒素（MCs）严重威胁生态健康。木犀草素作为一种低成本、生态安全的杀藻剂，具有杀灭铜绿微囊藻的潜力，但提高其杀藻效果的可持续性并在蛋白质组水平上阐明其潜在机制是当务之急。本研究优化构建了木犀草素的连续释放微球（CRM），即使在长期浸泡后也具有很强的坚固性和耐用性。应用木犀草素 CRM，本研究开发了一种长期杀藻方法，可强烈抑制微囊藻的生长和 MC 释放，直到 49 天，其生长和 MC 释放的抑制率（均≥98%）以及 CRM 的抑制效果持续时间（近 50 天）均优于大多数先前的报道，并且 CRM 对微囊藻生长和 MC 释放的长期强烈抑制作用在各种氮水平下保持稳定。此外，木犀草素 CRM 使细胞外 MC 含量降低到饮用水的可接受阈值附近。这表明木犀草素 CRM 在不同富营养化状态的水中对产毒 MCBs 进行持续有效控制具有广阔的应用前景。比较蛋白质组学分析表明，木犀草素 CRM 显著上调了光合作用和蛋白质同源性，但下调了其他过程，包括应激反应、MC 合成/释放、糖酵解、氨基酸合成、脂肪酸合成/β-氧化、三羧酸循环、转录、翻译、运输、细胞形态和细胞分裂。这意味着 CRM 持续释放的木犀草素会引起铜绿微囊藻蛋白质组向更高的能量储存但更低的能量释放/消耗转移，从而极大地扰乱了其生理代谢过程，从而对其生长产生负面影响。蛋白质组学结果为 CRM 形式的类黄酮的杀藻机制提供了新的深入见解。
