Transcriptomic responses combined with apical adverse ecologically relevant outcomes have proven to be useful to unravel and anchor molecular mechanisms of action to adverse outcomes. This is the case for feeding inhibition responses in the model ecotoxicological species Daphnia magna. The aim of the present study was to assess the transcriptomic responses in guts dissected from D. magna individuals exposed to concentrations of selected compounds that inhibit feeding and compare them with the responses associated to 2 levels of food restriction (low food and starvation). Chemical treatments included cadmium, copper, fluoranthene, λ-cyhalothrin, and the cyanotoxin anatoxin-a. Although the initial hypothesis was that exposure to chemical feeding inhibitors should elicit similar molecular responses as food limitation, the corresponding gut transcriptomic responses differed significantly. In moderate food limitation conditions, D. magna individuals increased protein and carbohydrate catabolism, likely to be used as energetic sources, whereas under severe starving conditions most metabolism-related pathways appeared down-regulated. Treatment with chemical feeding inhibitors promoted cell turnover–related signaling pathways in the gut, probably to renew tissue damage caused by the reported oxidative stress effects of these compounds, and inhibited the transcription of gut digestive gene enzymes and energetic metabolic pathways. We conclude that chemical feeding inhibitors, rather than mimicking the physiological response to low- or no-food conditions, cause specific toxic effects, preventing Daphnia both from feeding and from adjusting its metabolism to the resulting low energy intake. Environ Toxicol Chem 2021;40:2510–2520. © 2021 SETAC

中文翻译：

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Daphnia magna 肠道特异性转录组对摄食抑制化学品和食物限制的反应

转录组反应与顶端不良生态相关结果相结合已被证明有助于解开和锚定不良结果的分子作用机制。模型生态毒理学物种Daphnia magna的摄食抑制反应就是这种情况。本研究的目的是评估从D. magna解剖的肠道中的转录组学反应暴露于抑制进食的选定化合物浓度的个体，并将它们与与 2 级食物限制（低食物和饥饿）相关的反应进行比较。化学处理包括镉、铜、荧蒽、λ-三氯氟氰菊酯和蓝藻毒素类毒素-a。尽管最初的假设是暴露于化学喂养抑制剂应该引起与食物限制相似的分子反应，但相应的肠道转录组反应显着不同。在适度的食物限制条件下，D. magna个体增加了蛋白质和碳水化合物的分解代谢，可能被用作能量来源，而在严重的饥饿条件下，大多数与代谢相关的途径似乎被下调。用化学喂养抑制剂治疗促进了肠道中与细胞更新相关的信号通路，可能是为了更新由这些化合物的氧化应激效应引起的组织损伤，并抑制肠道消化基因酶和能量代谢途径的转录。我们得出结论，化学喂养抑制剂不是模仿对低食物或无食物条件的生理反应，而是引起特定的毒性作用，防止水蚤进食和调整其代谢以适应由此产生的低能量摄入。环境毒物化学2021；40：2510–2520。© 2021 SETAC