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Analysis of shell formation from calcium carbonate crystals in species specific manner

以物种特异性方式分析碳酸钙晶体的壳形成

基本信息

批准号：
15570055
负责人：
MIYAMOTO Hiroshi
金额：
$ 2.05万
依托单位：
Kinki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

In molluscs, biominerals of CaCO_3 are formed as shells with extremely divergent morphologies among species, enabling classification and identification of species. Shells are genetically regulated biominerals which consist of an external periostracal layer and an inner calcareous layer which is composed of several layers, such as a foliate, crossed lamellar, prismatic and nacreous layer. These layers are composed of CaCO_3, but their crystal types vary according to species ; in most pearl oysters, calcite in the prismatic layer and aragonite in the nacreous layer. The aragonitic nacreous layer is known as mother-of-pearl and consists of compact tablets of several hundreds nm in diameter. It is reported that its toughness is 1000 times greater than simple aragonite crystals produced by a chemical procedure. In addition to CaCO_3, mollusc shells contain as minor components organic matrix proteins, which are thought to be responsible for the toughness on the nacreous layer and to have some critical roles in calcification. In this research, I carried out analysis of genes expressed in the mantle. The results are as follows :1.Several housekeeping genes that are expressed in the oyster mantle were isolated and their primary structure were determined.2.Novel genes encoding glycine-rich proteins were isolated from the oyster mantle and their primary structure were determined. Recombinant proteins produced using the cDNAs inhibited the calcium carboane crystallization.3.The nacrein protein, which is found in the nacreous layer of the pearl oyster, has inhibitory activity in the calcium carbonate crystallization4.Novel genes encoding glycine-rich proteins in the pearl oyster were discovered and their entire nucleotide sequence were determined.

在软体动物中，CaCO_3的生物矿物形成为贝壳，在物种之间具有极其不同的形态，使得物种的分类和鉴定成为可能。贝壳是一种受遗传调控的生物矿物，由外层的角质层和内层的钙质层组成，钙质层由几层组成，如叶状层、交叉层状层、棱柱层和珍珠层。这些层由CaCO_3组成，但它们的晶体类型因种类而异;在大多数珍珠牡蛎中，棱柱层中的方解石和珍珠层中的文石。文石珍珠层被称为珍珠母，由直径数百纳米的致密片组成。据报道，它的韧性是1000倍以上，比简单的文石晶体生产的化学过程。除了CaCO_3外，软体动物贝壳还含有少量的有机基质蛋白，它们被认为是贝壳层韧性的主要来源，并在钙化过程中起着重要作用。在这项研究中，我进行了基因表达的地幔分析。主要研究结果如下：1.从牡蛎外套膜中分离到了几个管家基因，并对其进行了一级结构分析; 2.从牡蛎外套膜中分离到了编码富含甘氨酸蛋白的新基因，并对其进行了一级结构分析。3.珍珠层中的核壳素蛋白对碳酸钙结晶具有抑制活性。4.发现了编码珍珠富含甘氨酸蛋白的新基因，并测定了其核苷酸序列。