Microtexture of larval shell of oyster, Crassostrea nippona: A FIB-TEM study
Microtexture of larval shell of oyster, Crassostrea nippona: A FIB-TEM study
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DOI：
10.1016/j.jsb.2009.07.014
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发表时间：
2010-01-01
影响因子：
3
通讯作者：
Kogure, Toshihiro
中科院分区：
文献类型：
--
作者：
Kudo, Miki;Kameda, Jun;Kogure, Toshihiro
利用纤维束透射电镜技术研究了日本近江牡蛎（Crassostrea nippona）幼体贝壳的形成和发育过程。受精后14小时（担轮幼虫阶段），幼虫形成100-150 nm厚的初始壳，具有柱状对比。选区电子衍射分析表明，单晶文石图案的c轴垂直于壳表面。平面图TEM分析表明，壳包含高密度的{110}孪晶，这是横截面图像中柱状对比度的来源。受精后72 h（面盘阶段），壳厚达1.2-1.4 μ m，在原壳层和胚之间增加一层颗粒层，形成独特的双层结构。颗粒层也由文石晶体组成，文石晶体共享垂直于壳表面的c轴，但晶体围绕c轴灵活旋转排列，而不仅仅限于{110}孪晶关系。通过观察没有发现无定形碳酸钙（ACC）存在的证据。在本样品中发现的良好调节的晶体学性质意味着初始壳的形成可能是通过直接沉积的结晶文石。(C)2009 Elsevier Inc. All rights reserved.
The initial formation and subsequent development of larval shells in marine bivalve, Crassostrea nippona were investigated using the FIB-TEM technique. Fourteen hours after fertilization (the trochophore stage), larvae form an incipient shell of 100-150 nm thick with a columnar contrast. Selected-area electron diffraction analysis showed a single-crystal aragonite pattern with the c-axis perpendicular to the shell surface. Plan-view TEM analysis suggested that the shell contains high density of {110} twins, which are the origin of the columnar contrast in the cross-sectional images. 72 h after fertilization (the veliger stage), the shell grows up to 1.2-1.4 mu m thick accompanying an additional granular layer between the preexisting layer and embryo to form a distinctive two-layer structure. The granular layer is also composed of aragonite crystals sharing their c-axes perpendicular to the shell surface, but the crystals are arranged with a flexible rotation around the c-axes and not restricted solely to the {110} twin relation. No evidence to suggest the existence of amorphous calcium carbonate (ACC) was found through the observation. The well-regulated crystallographic properties found in the present sample imply initial shell formation probably via a direct deposition of crystalline aragonite. (C) 2009 Elsevier Inc. All rights reserved.