The mass proliferation of cyanobacteria, episodes known as blooms, is a concern worldwide. One of the most critical aspects during these blooms is the production of toxic secondary metabolites that are not limited to the four cyanotoxins recognized by the World Health Organization. These metabolites comprise a wide range of structurally diverse compounds that possess bioactive functions. Potential human and ecosystem health risks posed by these metabolites and co-produced mixtures remain largely unknown. We studied acute lethal and sublethal effects measured as impaired mobility on the freshwater microcrustaceans for metabolite mixtures from two cyanobacterial strains, a microcystin (MC) producer and a non-MC producer. Both cyanobacterial extracts, from the MC-producer and non-MC-producer, caused acute toxicity with LC (24 h) values of 0.50 and 2.55 mg/mL, respectively, and decreased locomotor activity. Evaluating the contribution of different cyanopeptides revealed that the Micropeptin-K139-dominated fraction from the MC-producer extract contributed significantly to mortality and locomotor impairment of the microcrustaceans, with potential mixture effect with other cyanopeptolins present in this fraction. In the non-MC-producer extract, compounds present in the apolar fraction contributed mainly to mortality, locomotor impairment, and morphological changes in the antennae of the microcrustacean. No lethal or sublethal effects were observed in the fractions dominated by other cyanopetides (Cyanopeptolin 959, Nostoginin BN741). Our findings contribute to the growing body of research indicating that cyanobacterial metabolites beyond traditional cyanotoxins cause detrimental effects. This underscores the importance of toxicological assessments of such compounds, also at sublethal levels.

中文翻译：

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半纯化微囊藻毒素、微肽素和蓝藻非极性化合物对淡水微甲壳类动物的致死和行为影响


蓝藻的大规模增殖（称为水华）是全世界关注的问题。这些水华期间最关键的方面之一是有毒次生代谢物的产生，这些代谢物不仅限于世界卫生组织认可的四种蓝藻毒素。这些代谢物包含多种具有生物活性功能的结构多样的化合物。这些代谢物和共同生产的混合物对人类和生态系统健康造成的潜在风险在很大程度上仍然未知。我们研究了两种蓝藻菌株（一种是微囊藻毒素（MC）生产者和一种非 MC 生产者）的代谢混合物的急性致死和亚致死效应，以淡水微甲壳类动物的活动性受损来衡量。来自 MC 生产者和非 MC 生产者的两种蓝藻提取物均引起急性毒性，LC（24 小时）值分别为 0.50 和 2.55 mg/mL，并降低运动活性。评估不同氰肽的贡献表明，MC 生产者提取物中以微肽素 K139 为主的级分对微甲壳类动物的死亡率和运动损伤有显着贡献，与该级分中存在的其他氰肽素具有潜在的混合效应。在非 MC 生产者提取物中，非极性部分中存在的化合物主要导致微型甲壳类动物的死亡率、运动障碍和触角形态变化。在以其他氰肽（Cyanopeptolin 959、Nostoginin BN741）为主的级分中未观察到致死或亚致死作用。我们的研究结果有助于越来越多的研究表明，传统蓝藻毒素之外的蓝藻代谢物会造成有害影响。 这强调了对此类化合物（包括亚致死水平）进行毒理学评估的重要性。