Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden
Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden.
Proc Biol Sci. 2018 Nov 14;285(1891):20181676. doi: 10.1098/rspb.2018.1676.
Calcium transport is essential for bivalves to be able to build and maintain their shells. Ionized calcium (Ca) is taken up from the environment and eventually transported through the outer mantle epithelium (OME) to the shell growth area. However, the mechanisms behind this process are poorly understood. The objective of the present study was to characterize the Ca transfer performed by the OME of the Pacific oyster, as well as to develop an Ussing chamber technique for the functional assessment of transport activities in epithelia of marine bivalves. Kinetic studies revealed that the Ca transfer across the OME consists of one saturable and one linear component, of which the saturable component fits best to Michaelis-Menten kinetics and is characterized by a of 6.2 mM and a of 3.3 nM min The transcellular transfer of Ca accounts for approximately 60% of the total Ca transfer across the OME of s at environmental Ca concentrations. The use of the pharmacological inhibitors: verapamil, ouabain and caloxin 1a1 revealed that voltage-gated Ca-channels, plasma-membrane Ca-ATPase and Na/Ca-exchanger all participate in the transcellular Ca transfer across the OME and a model for this Ca transfer is presented and discussed.
钙转运对于双壳类动物能够构建和维持其壳至关重要。离子化钙（Ca）从环境中吸收，并最终通过外膜上皮（OME）运输到壳生长区域。然而，这一过程的机制还知之甚少。本研究的目的是描述太平洋牡蛎 OME 进行的 Ca 转运，并开发一种用于评估海洋双壳类动物上皮细胞转运活性的 Ussing 室技术。动力学研究表明，OME 中的 Ca 转运由一个饱和和一个线性组成，其中饱和组成最符合米氏-门控动力学，其特征是 Km 值为 6.2 mM，Vmax 值为 3.3 nM min。在环境 Ca 浓度下，Ca 通过质膜的跨细胞转运约占 OME 总 Ca 转运的 60%。使用药理学抑制剂维拉帕米、哇巴因和 caloxin 1a1 表明，电压门控 Ca 通道、质膜 Ca-ATP 酶和 Na/Ca 交换器都参与了 OME 中的跨细胞 Ca 转运，并提出并讨论了该 Ca 转运的模型。
