Without Gills: Localization of Osmoregulatory Function in the Copepod Eurytemora affinis
Without Gills: Localization of Osmoregulatory Function in the Copepod Eurytemora affinis
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DOI：
10.1086/674319
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发表时间：
2014-03-01
影响因子：
1.6
通讯作者：
Lee, Carol Eunmi
中科院分区：
文献类型：
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作者：
Johnson, Kelsey Elizabeth;Perreau, Lucile;Lee, Carol Eunmi
泛甲壳纲，包括甲壳类和六足类，已经成功地殖民了海洋，淡水和陆地栖息地。而软甲纲的成员（例如，蟹，虾）通常显示出巨大的生物调节能力，更基部分支的甲壳类动物（例如，桡足类，鳃足类）往往拥有不太专业的调节结构，已经很差的特点。值得注意的是，这些更基础的类群中的一些也定居在不同的栖息地。例如，桡足类Eurytemora affinis最近多次独立入侵淡水栖息地，但缺乏明显的调节结构。为了探索离子交换的定位，我们进行了银染色，免疫组织化学染色和透射电子显微镜。我们的研究结果揭示了离子运输的上颌腺内和四对游泳腿的本地化。银染色显示离子交换的上颌孔和内足和外足的游泳腿P1至P4。免疫组化检测结果显示，上颚腺和游泳腿中存在离子转运酶V型H+-ATP酶和Na+/K+-ATP酶。最后，透射电子显微镜确定专门的离子细胞在这些解剖区域。这些研究发现了游泳腿上的新的调节结构，我们将其命名为Crusalis器官。我们的研究结果确定了专门用于离子运输的特定组织，可能使这种小型甲壳动物能够迅速过渡到淡水栖息地。
The Pancrustacea, which include crustaceans and hexapods, have successfully colonized marine, freshwater, and terrestrial habitats. While members of the class Malacostraca (e.g., crabs, shrimp) often display immense osmoregulatory capacities, more basally branching crustaceans (e.g., copepods, branchiopods) tend to possess less-specialized osmoregulatory structures that have been poorly characterized. Remarkably, some of these more basal taxa have also colonized diverse habitats. For instance, the copepod Eurytemora affinis has recently invaded freshwater habitats multiple times independently but lack obvious osmoregulatory structures. To explore localization of ion exchange, we performed silver staining, immunohistochemical staining, and transmission electron microscopy. Our results revealed localization of ion transport within the maxillary glands and on four pairs of swimming legs. Silver staining revealed ion exchange at the maxillary pores and on the endopods and exopods of swimming legs P1 through P4. Immunohistochemical assays localized ion transport enzymes V-type H+-ATPase and Na+/K+-ATPase in the maxillary glands and swimming legs as well. Finally, transmission electron microscopy identified specialized ionocytes within these anatomical regions. These investigations uncovered novel osmoregulatory structures at the swimming legs, which we designate the Crusalis organs. Our findings identified specific tissues specialized for ion transport, potentially enabling this small crustacean to rapidly transition into freshwater habitats.