Abstract：
The secondary outbreak of cyanobacteria after algicide treatment has been a serious problem to water ecosystems. Hydrogen peroxide (H2O2) is an algaecide widely used in practice, but similar re-bloom problems are inevitably encountered. Our work found that Microcystis aeruginosa (M. aeruginosa) temporarily hibernates after H2O2 treatment, but there is still a risk of secondary outbreaks. Interestingly, the dormant period was as long as 20 and 28 days in 5 mg L-1 and 20 mg L-1 H2O2 treatment groups, respectively, but the photosynthetic activity was both restored much earlier (within 14 days). Subsequently, a quantitative imaging flow cytometry-based method was constructed and confirmed that the re-bloom had undergone two stages including first recovery and then re-division. The expression of ftsZ and fabZ genes showed that M. aeruginosa had active transcription processes related to cell division protein and fatty acid synthesis during the dormancy stat. Furthermore, metabolomics suggested that the recovery of M. aeruginosa was mainly by activating folate and salicylic acid synthesis pathways, which promoted environmental stress resistance, DNA synthesis, and cell membrane repair. This study reported the comprehensive mechanisms of secondary outbreak of M. aeruginosa after H2O2 treatment. The findings suggest that optimizing the dosage and frequency of H2O2, as well as exploring the potential use of salicylic acid and folic acid inhibitors, could be promising directions for future algal control strategies.
摘要：
除藻剂处理后蓝藻的二次爆发一直是水生态系统的严重问题。过氧化氢(H2O2)是一种在实践中广泛使用的除藻剂,但是不可避免地会遇到类似的重新开花问题。我们的工作发现铜绿微囊藻(M.铜绿假)H2O2处理后暂时冬眠，但仍有二次爆发的风险。有趣的是,5mgL-1和20mgL-1H2O2治疗组的休眠期长达20和28天，分别,但是光合活性都恢复得更早（在14天内）。随后，我们构建了一种基于流式细胞术的定量成像方法,并证实重新开花经历了两个阶段,包括首先恢复,然后重新分裂.ftsZ和fabZ基因的表达表明，铜绿假单胞菌在休眠期间具有与细胞分裂蛋白和脂肪酸合成相关的活跃转录过程。此外，代谢组学表明铜绿假单胞菌的回收主要通过激活叶酸和水杨酸合成途径,这促进了环境胁迫抗性，DNA合成，和细胞膜修复。本研究报道了H2O2治疗后铜绿假单胞菌二次暴发的综合机制。研究结果表明，优化H2O2的剂量和频率，以及探索水杨酸和叶酸抑制剂的潜在用途，可能是未来藻类控制策略的有希望的方向。
