珍珠层有机质及其矿化响应研究

Organic matter in nacre and its mineralization effect

珍珠层中的有机质极其重要,它不仅是生物矿物与纯无机矿物的根本区别,而且具有重要的生物矿化响应效应。但珍珠层中有机质含量极低,约为珍珠层体积的5%,致使研究手段受到了很大限制。选择广西、广东、浙江、江苏等地的海水养殖珍珠、淡水养殖珍珠、育珠贝贝壳中的珍珠层以及现代珊瑚、珊瑚化石作为研究对象,通过日立835-50型高速氨基酸分析仪获得了各样品氨基酸的种类和含量,继而进行相关性分析和聚类分析,得到一些具有特点的氨基酸组合或类,结合对珍珠层进行的TEM、SEM等电镜观察结果,发现这些组合和类很可能分别对应于珍珠层中不同空间位置、不同结构、不同种类和不同形态大小的有机大分子。由此认为有机质的矿化响应十分复杂、多样,并可以通过诱导和控制作用形成多样化、相互演化、复杂的无机矿物及珍珠层独特的微结构。这一结论对于阐释珍珠层有机质复杂多样的矿化响应具有重要意义。

Although its concentration is extremely low （about 5 % of the volume of nacre） and its research technique is limited, the organic matrix in nacre not only is the most fundamental difference between biominerals and natural inorganic minerals but also has an important effect on biomineralization. In this study, the nacres of pearls and shells cultured in freshwaters and seawaters in Guangxi, Guangdong, Zhejiang and Jiangsu and those in corals were tested by Hitachi 835-50 High speed Amino Acid Analyzer and, as a result, the sorts and content of amino acids of organic matrix in nacre specimens were acquired. In combination with the microtopograpgy of nacre＇s organics investigated by SEM and HRTEM, the correlation analysis and cluster analysis produced some special amino acid constitutions or categories, which correspond to different organic rnacromolecules in different spatial positions, structures, kinds, shapes or sizes of nacres. These analyses show that the mineralization effect of organic matrix in nacre is characterized by diversity and complexity, which results in the diversity and complexity of inorganic minerals in species, size, evolution. Hence the unique microstructure of nacre can be formed by inducing and controlling. The conclusion obtained by the authors is significant for understanding the effect of organic matrix on biomineralization in nacre.