Microcystins (MCs) are potent toxins produced by environmental cyanobacterial blooms. The present study evaluated the effects of a Microcystis aeruginosa cyanobacterial lysate containing 0.1, 1, and 10 μg L−1 MC‐LR equivalent in the C. elegans Bristol N2 wild‐type and the effects caused by equivalent concentrations of a MC‐LR standard. The lysate was prepared from a culture of toxic strain (RST9501) originated from the Patos Lagoon Estuary (RS, Brazil). The minimal concentration necessary to cause significant effects in C. elegans under exposure to M. aeruginosa lysate or to MC‐LR standard were, respectively, 10 and 0.1 μg L−1 MC‐LR equivalent for growth and 10 and 1 μg L−1 MC‐LR equivalent for fertility. Reproduction (ie, brood size) was only affected by the exposure to 10 μg L−1 MC‐LR standard and was not affected by the lysate. The nematodes that were exposed to lysate containing 1 μg L−1 MC‐LR equivalent or MC‐LR were also analyzed for pharyngeal pumping and gene expression using RT‐qPCR. The worms’ rhythmic contractions of the pharynx were similarly affected by the lysate containing 1 μg L−1 of MC‐LR equivalent and the MC‐LR standard. The MC‐LR standard caused down‐regulation of genes related to growth (daf‐16), fertility (spe‐10), and biotransformation (gst‐2). This is the first study to evaluate the effects of a toxic cyanobacterial lysate using the C. elegans model. This study suggests the organism as a potential biotest to evaluate toxicity of natural waters containing M. aeruginosa cells and to environmental risk assessment associated to cyanobacterial bloom events.

中文翻译：

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含有微囊藻毒素的铜绿微囊藻细胞裂解液对线虫秀丽隐杆线虫生理和分子反应的影响

微囊藻毒素 (MC) 是由环境蓝藻大量繁殖产生的强效毒素。本研究评估了含有 0.1、1 和 10 μg L-1 MC-LR 等效物的铜绿微囊藻蓝藻裂解物对秀丽隐杆线虫 Bristol N2 野生型的影响以及等效浓度的 MC-LR 标准品引起的影响. 裂解液是从源自帕托斯泻湖河口（RS，巴西）的有毒菌株（RST9501）的培养物中制备的。在暴露于铜绿假单胞菌裂解物或 MC-LR 标准品的情况下，对秀丽隐杆线虫产生显着影响所需的最低浓度分别为 10 和 0.1 μg L-1 MC-LR 等价物，10 和 1 μg L-1 MC-LR 等价于生育能力。繁殖（即育雏大小）仅受暴露于 10 μg L-1 MC-LR 标准的影响，不受裂解物的影响。还使用 RT-qPCR 分析了暴露于含有 1 μg L-1 MC-LR 等价物或 MC-LR 的裂解液的线虫的咽泵和基因表达。蠕虫的咽部节律性收缩同样受到含有 1 μg L-1 MC-LR 等效物和 MC-LR 标准物的裂解物的影响。MC-LR 标准导致与生长 (daf-16)、生育力 (spe-10) 和生物转化 (gst-2) 相关的基因下调。这是第一项使用秀丽隐杆线虫模型评估有毒蓝藻裂解物影响的研究。该研究表明，该生物体可作为一种潜在的生物测试，用于评估含有铜绿假单胞菌细胞的天然水的毒性以及与蓝藻水华事件相关的环境风险评估。