Some properties of otoconia.
Some properties of otoconia.
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耳石的一些特性。
DOI：
10.1098/rstb.1984.0038
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Pote,KG
中科院分区：
文献类型：
--
作者：
Ross,MD;Pote,KG
耳石是存在于大多数脊椎动物的重力感受器中的动态矿物沉积物;鱼类通常具有称为耳石的单个大质量。耳石通常具有单晶的外观，但含有有机和无机成分，矿物几乎完全是碳酸钙的多晶型物。这两个阶段在结构上密切相关。大鼠耳石的超高分辨透射电镜显示它们是镶嵌的生物矿物。晶粒直径为50-100 nm，具有一些圆形边缘，并且高度有序地形成薄片。这表明微晶播种和生长是有机基质介导的。微晶的不对称性也可以表示压电性。从青蛙和大鼠耳石中获得的电子束衍射图案的相似性进一步发现可能意味着哺乳动物单位的方解石模仿文石。一项比较研究表明，接近哺乳动物干线的海龟在椭圆囊中具有方解石型耳石。短吻鳄与鸟类有着共同的祖先，在所有三个重力感受器中都有这种类型的耳锥，尽管囊状耳锥有各种各样的形式。这种矿物的性质尚不清楚。有机耳石物质的生物化学成分正在研究中，以了解矿物质沉积是如何调节的。大鼠耳石复合体的蛋白质介于a。16 500和100 000 Da以上，囊状和椭圆囊状耳锥复合体的分子量相似。我们通过高效液相色谱法对复合物的氨基酸组成进行了新的分析，结果表明复合物的酸性氨基酸含量高，碱性氨基酸含量低。这与已经报道的含有方解石的其他生物矿化材料的情况相当。
Otoconia are dynamic mineral deposits present in the gravity receptors of most vertebrates; fishes often have a single large mass called an otolith instead. Otoconia generally have the appearance of single crystals but contain organic and inorganic components, the mineral being almost exclusively a polymorph of calcium carbonate. The two phases are closely interrelated structurally. Ultra-high resolution transmission electron microscopy of rat otoconia showed them to be mosaic biominerals. The crystallites were 50-100 nm in diameter, had some rounded edges, and were highly ordered into laminae. This suggests that crystallite seeding and growth is organic matrix mediated. Crystallite asymmetry may also indicate piezoelectricity. A further finding of similarities in electron beam diffraction patterns obtained from some frog and rat otoconia could mean that the calcite of mammalian units mimics aragonite. A comparative study showed that turtles, which are close to the stem line for mammals, had calcite-type otoconia in the utricle. Alligators, which share a common ancestry with birds, had this type otoconium in all three gravity receptors, although saccular otoconia had a variety of forms. The nature of the mineral is unknown. The biochemical composition of the organic otoconial material is under study, to learn how mineral deposition is regulated. Proteins of rat otoconial complexes ranged betweenca. 16 500 and over 100 000 Da in molecular mass and were similar in saccular and utricular otoconial complexes. Our new analysis of the amino acid composition of the complexes by high performance liquid chromatography showed the complexes to be high in the acidic and low in the basic amino acids. This is comparable to what has already been reported for other biomineralized materials that contain calcite.