School of Pharmaceutical Sciences, University of São Paulo, 05508-900, São Paulo, Brazil.
School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom, B15 2TT.
Aquat Toxicol. 2023 Oct;263:106689. doi: 10.1016/j.aquatox.2023.106689. Epub 2023 Sep 9.
Cyanobacterial blooms affect aquatic ecosystems across the globe and one major concern relates to their toxins such as microcystins (MC). Yet, the ecotoxicological risks, particularly non-lethal effects, associated with other co-produced secondary metabolites remain mostly unknown. Here, we assessed survival, morphological alterations, swimming behaviour and cardiovascular functions of zebrafish (Danio rerio) upon exposure to cyanobacterial extracts of two Brazilian Microcystis strains. We verified that only MIRS-04 produced MCs and identified other co-produced cyanopeptides also for the MC non-producer NPCD-01 by LC-HRMS/MS analysis. Both cyanobacterial extracts, from the MC-producer and non-producer, caused acute toxicity in zebrafish with LC values of 0.49 and 0.98 mg/mL, respectively. After exposure to MC-producer extract, additional decreased locomotor activity was observed. The cyanopeptolin (micropeptin K139) contributed 52% of the overall mortality and caused oedemas of the pericardial region. Oedemas of the pericardial area and prevented hatching were also observed upon exposure to the fraction with high abundance of a microginin (Nostoginin BN741) in the extract of the MC non-producer. Our results further add to the yet sparse understanding of lethal and sublethal effects caused by cyanobacterial metabolites other than MCs and the need to better understand the underlying mechanisms of the toxicity. We emphasize the importance of considering mixture toxicity of co-produced metabolites in the ecotoxicological risk assessment of cyanobacterial bloom events, given the importance for predicting adverse outcomes in fish and other organisms.
蓝藻水华影响着全球的水生生态系统，其中一个主要关注点是它们的毒素，如微囊藻毒素（MC）。然而，其他共生次级代谢产物所带来的生态毒理学风险，特别是非致死效应，在很大程度上仍不为人知。在这里，我们评估了暴露于两种巴西微囊藻菌株的蓝藻提取物后斑马鱼（Danio rerio）的存活率、形态改变、游泳行为和心血管功能。我们证实只有 MIRS-04 产生 MC，并通过 LC-HRMS/MS 分析鉴定了 MC 非生产者 NPCD-01 产生的其他共生蓝藻肽。来自 MC 生产者和非生产者的两种蓝藻提取物都对斑马鱼造成了急性毒性，LC 值分别为 0.49 和 0.98mg/mL。暴露于 MC 生产者提取物后，观察到额外的运动活性降低。蓝藻肽（微肽 K139）导致 52%的总死亡率，并引起心包区域水肿。在心包区域水肿和孵化受阻方面，也观察到了 MC 非生产者提取物中高丰度微肌肽（Nostoginin BN741）部分暴露的现象。我们的研究结果进一步补充了关于除 MC 以外的蓝藻代谢物引起的致死和亚致死效应的认识，需要更好地理解毒性的潜在机制。我们强调了在蓝藻水华事件的生态毒理学风险评估中考虑共生代谢物混合物毒性的重要性，因为这对于预测鱼类和其他生物的不良后果非常重要。
