Dinoflagellates are important aquatic microbes and major harmful algal bloom (HAB) agents that form invasive species through ship ballast transfer. UV-C installations are recommended for ballast treatments and HAB controls, but there is a lack of knowledge in dinoflagellate responses to UV-C. We report here dose-dependent cell cycle delay and viability loss of dinoflagellate cells irradiated with UV-C, with significant proliferative reduction at 800 Jm⁻² doses or higher, but immediate LD50 was in the range of 2400–3200 Jm⁻². At higher dosages, some dinoflagellate cells surprisingly survived after days of recovery incubation, and continued viability loss, with samples exhibiting DNA fragmentations per proliferative resumption. Sequential cell cycle postponements, suggesting DNA damages were repaired over one cell cycle, were revealed with flow cytometric analysis and transcriptomic analysis. Over a sustained level of other DNA damage repair pathways, transcript elevation was observed only for several components of base pair repair and mismatch repair. Cumulatively, our findings demonstrated special DNA damage responses in dinoflagellate cells, which we discussed in relation to their unique chromo-genomic characters, as well as indicating resilience of dinoflagellate cells to UV-C.

中文翻译：

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甲藻细胞对紫外线-C 照射的反应

甲藻是重要的水生微生物和主要的有害藻华 (HAB) 剂，它们通过船舶压舱物转移形成入侵物种。建议将 UV-C 安装用于镇流器处理和 HAB 控制，但对甲藻对 UV-C 的反应缺乏了解。我们在此报告用 UV-C 照射的甲藻细胞的剂量依赖性细胞周期延迟和活力丧失，在 800 Jm ^-2剂量或更高剂量下显着增殖减少，但即时 LD50 在 2400-3200 Jm ^-2范围内. 在较高剂量下，一些甲藻细胞在经过数天的恢复孵育和持续的生存能力丧失后出人意料地存活下来，样本在每次增殖恢复时都显示出 DNA 碎片。通过流式细胞术分析和转录组学分析揭示了连续的细胞周期延迟，表明 DNA 损伤在一个细胞周期内得到修复。在其他 DNA 损伤修复途径的持续水平上，仅观察到碱基对修复和错配修复的几个组成部分的转录物升高。总的来说，我们的研究结果证明了甲藻细胞的特殊 DNA 损伤反应，我们讨论了与它们独特的染色体基因组特征相关的问题，并表明甲藻细胞对 UV-C 的恢复能力。