Department of Microbiology, Dartmouth Medical School, Hanover, NH 03755, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2012 Mar;161(3):320-6. doi: 10.1016/j.cbpa.2011.11.014. Epub 2011 Dec 13.
Estuarine fish, such as the Atlantic killifish (Fundulus heteroclitus), are constantly and rapidly exposed to changes in salinity. Although ion transport in killifish gills during acclimation to increased salinity has been studied extensively, no studies have examined the role of aquaglyceroporin 3 (AQP3), a water, glycerol, urea, and ammonia transporter, during acclimation to increased salinity in this sentinel environmental model organism. The goal of this study was to test the hypothesis that transfer from freshwater to seawater decreases AQP3 gene and protein expression in the gill of killifish. Transfer from freshwater to seawater decreased AQP3 mRNA in the gill after 1 day, but had no effect on total gill AQP3 protein abundance as determined by western blot. Quantitative confocal immunocytochemistry confirmed western blot studies that transfer from freshwater to seawater did not change total AQP3 abundance in the gill; however, immunocytochemistry revealed that the amount of AQP3 in pillar cells of secondary lamellae decreased in seawater fish, whereas the amount of AQP3 in mitochondrion rich cells (MRC) in primary filaments of the gill increased in seawater fish. This response of AQP3 expression is unique to killifish compared to other teleosts. Although the role of AQP3 in the gill of killifish has not been completely elucidated, these results suggest that AQP3 may play an important role in the ability of killifish to acclimate to increased salinity.
河口鱼类，如大西洋小沙丁鱼（Fundulus heteroclitus），经常且迅速地暴露于盐度变化中。尽管在适应高盐度时，小沙丁鱼鳃中的离子转运已被广泛研究，但尚无研究检查水甘油通道蛋白 3（AQP3）在适应增加盐度中的作用，AQP3 是一种水、甘油、尿素和氨转运蛋白，在这个环境哨兵模式生物中。本研究的目的是检验这样一个假设，即从淡水转移到海水会降低鳃中小沙丁鱼的 AQP3 基因和蛋白表达。从淡水转移到海水后，1 天内鳃中的 AQP3 mRNA 减少，但 Western blot 并未显示总鳃 AQP3 蛋白丰度受到影响。定量共聚焦免疫细胞化学证实了 Western blot 研究，即从淡水转移到海水不会改变鳃中总 AQP3 丰度；然而，免疫细胞化学显示，次级鳃片柱细胞中的 AQP3 量在海水鱼中减少，而富含线粒体的细胞（MRC）在鳃的初级丝中增加。与其他硬骨鱼相比，这种 AQP3 表达的反应是小沙丁鱼所特有的。尽管 AQP3 在小沙丁鱼鳃中的作用尚未完全阐明，但这些结果表明 AQP3 可能在小沙丁鱼适应高盐度的能力中发挥重要作用。
