Physiological plasticity and acclimatory responses to salinity stress are ion-specific in the mayfly, Neocloeon triangulifer
Physiological plasticity and acclimatory responses to salinity stress are ion-specific in the mayfly, Neocloeon triangulifer
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蜉蝣 Neocloeon triangulifer 的生理可塑性和对盐度胁迫的适应反应具有离子特异性
DOI：
10.1016/j.envpol.2021.117221
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发表时间：
2021
影响因子：
8.9
通讯作者：
Buchwalter, David B.
中科院分区：
文献类型：
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作者：
Orr, Sarah E.;Negrão Watanabe, Tatiane Terumi;Buchwalter, David B.
淡水盐碱化是一个迅速出现的生态问题，与水生生物多样性的显着下降相关。目前尚不清楚盐度变化如何影响敏感水生昆虫的生理机能。我们使用孤雌蜉蝣，Neocloeon triangulifer，来探究离子暴露历史如何改变生理过程和对随后主要离子暴露的反应。使用放射性示踪剂（22Na、35SO4 和 45Ca），我们观察到长期在高钠或硫酸盐（157 mg L−1Na 或 667 mg L−1SO4）中饲养的蜉蝣的离子摄取率比在稀对照水中饲养的蜉蝣低 2 倍（p < 0.0001）和 8 倍（p < 0.0001） （16 mg L−1Na 和 23 mg L−1SO4），随后分别转移至高盐度。这些适应离子传输的变化为钠的 96 小时毒性生物测定提供了保护，但没有为硫酸盐提供保护。有趣的是，钙的摄取量一致低得多，并且受暴露史的影响最小，但在毒性生物测定中的耐受性很差。通过qRT-PCR，我们观察到蜉蝣中许多离子转运蛋白基因的表达受到盐度升高以离子特异性方式的影响（一般对硫酸盐反应上调，对钙反应下调）。增加钠暴露对相同基因的影响很小。最后，我们提供了马氏小管（昆虫初级排泄系统）上皮内组织形态学变化的新的光学显微镜证据，这些变化经历了继发于钙毒性的细胞变性和坏死。我们得出结论，盐度胁迫的生理可塑性是离子特异性的，并为 N 中离子特异性毒性机制提供了证据。三角藻。
Freshwater salinization is a rapidly emerging ecological issue and is correlated with significant declines in aquatic biodiversity. It remains unclear how changing salinity regimes affect the physiology of sensitive aquatic insects. We used the parthenogenetic mayfly,Neocloeon triangulifer,to ask how ionic exposure history alters physiological processes and responses to subsequent major ion exposures. Using radiotracers (22Na,35SO4, and45Ca), we observed that mayflies chronically reared in elevated sodium or sulfate (157 mg L−1Na or 667 mg L−1SO4) had 2-fold (p < 0.0001) and 8-fold (p < 0.0001) lower ion uptake rates than mayflies reared in dilute control water (16 mg L−1Na and 23 mg L−1SO4) and subsequently transferred to elevated salinities, respectively. These acclimatory ion transport changes provided protection in 96-h toxicity bioassays for sodium, but not sulfate. Interestingly, calcium uptake was uniformly much lower and minimally influenced by exposure history, but was poorly tolerated in the toxicity bioassays. With qRT-PCR, we observed that the expression of many ion transporter genes in mayflies was influenced by elevated salinity in an ion-specific manner (general upregulation in response to sulfate, downregulation in response to calcium). Elevated sodium exposure had minimal influence on the same genes. Finally, we provide novel light microscopic evidence of histomorphological changes within the epithelium of the Malpighian tubules (insect primary excretory system) that undergoes cellular degeneration and necrosis secondary to calcium toxicity. We conclude that physiological plasticity to salinity stress is ion-specific and provide evidence for ion-specific toxicity mechanisms inN. triangulifer.