Morphological and functional classification of ion-absorbing mitochondria-rich cells in the gills of Mozambique tilapia
Morphological and functional classification of ion-absorbing mitochondria-rich cells in the gills of Mozambique tilapia
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DOI：
10.1242/jeb.025957
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发表时间：
2009-04-01
影响因子：
2.8
通讯作者：
Kaneko, Toyoji
中科院分区：
文献类型：
--
作者：
Inokuchi, Mayu;Hiroi, Junya;Kaneko, Toyoji
为阐明富钠细胞（MR）的离子吸收功能及其分子机制，将莫桑比克罗非鱼（Oreochromis mossambicus）驯化到正常或低Na+/正常Cl-（对照）、正常Na +/低Cl-、低Na+/正常Cl-和低Na+/低Cl-的人工淡水中。扫描电子显微镜（SEM）显示，凹和凸的MR细胞的顶端表面主要发达国家在低Na+和低Cl-沃茨，分别，而小的顶端坑占主导地位，在控制条件。低Na+沃茨（低Na+/正常Cl-和低Na+/低Cl-）使鳃Na+/H+交换体3（NHE 3）mRNA表达增加，而Na+/Cl-协同转运体（NCC）mRNA表达在低Cl-中上调，但在低Na+/低Cl-中不上调。免疫荧光染色显示，在低Na+沃茨中，NHE 3免疫反应阳性区呈凹形或扁平状，而在低Cl-沃茨中，NCC免疫反应阳性区呈凸形。扫描电镜免疫细胞化学显示NHE 3/NCC分布与扫描电镜图像比较，进一步证实NHE 3和NCC分别局限于凹顶和凸顶表面。这些结果表明，小的根尖坑发展成凹的根尖表面，以促进Na+吸收通过NHE 3，并成为凸的根尖表面，以提高Na+/Cl-吸收通过NCC。我们的研究结果整合了莫桑比克罗非鱼离子吸收MR细胞的形态和功能分类。
To clarify ion-absorbing functions and molecular mechanisms of mitochondria-rich (MR) cells, Mozambique tilapia (Oreochromis mossambicus) were acclimated to artificial freshwaters with normal or lowered Na+ and/or Cl- concentration: (1) normal Na+/normal Cl- (control); (2) normal Na+/low Cl-; (3) low Na+/normal Cl-; and (4) low Na+/low Cl-. Scanning electron microscopy (SEM) revealed that concave and convex apical surfaces of MR cells predominantly developed in low Na+ and low Cl- waters, respectively, whereas small apical pits predominated in control conditions. Expression of Na+/H+ exchanger-3 (NHE3) mRNA in the gills was increased in low Na+ waters (low Na+/normal Cl- and low Na+/low Cl-), whereas that of Na+/Cl- cotransporter (NCC) expression was upregulated in low Cl-, but not in low Na+/ low Cl-. Immunofluorescence staining showed that enlarged NHE3-immunoreactive apical regions were concave or flat in low Na+ waters, whereas NCC-immunoreactive regions were enlarged convexly in low Cl- waters. Using SEM immunocytochemistry the distribution of NHE3/NCC was compared with SEM images obtained simultaneously, it was further demonstrated that NHE3 and NCC were confined to concave and convex apical surfaces, respectively. These results indicated that small apical pits developed into concave apical surfaces to facilitate Na+ uptake through NHE3, and into convex apical surfaces to enhance Na+/Cl- uptake through NCC. Our findings integrated morphological and functional classifications of ion-absorbing MR cells in Mozambique tilapia.