The otoconia of the guinea pig utricle: Internal structure, surface exposure, and interactions with the filament matrix
The otoconia of the guinea pig utricle: Internal structure, surface exposure, and interactions with the filament matrix
复制标题
DOI：
10.1006/jsbi.2000.4260
复制
发表时间：
2000-07-01
影响因子：
3
通讯作者：
Kachar, B
中科院分区：
文献类型：
--
作者：
Lins, U;Farina, M;Kachar, B
脊椎动物重力感受器球囊和椭圆形的一个独特特征是大量的生物矿物结构，即耳锥，覆盖在感觉上皮表面的凝胶基质上，也称为“耳锥膜”。在哺乳动物中，耳石是碳酸钙的沉积物，呈复合方解石晶体的形式。我们用快速冷冻、深度蚀刻的方法检测了豚鼠椭圆体的耳锥体质量。深度蚀刻步骤暴露了大量完整和断裂的耳石，显示了其内部晶体结构、表面成分和嵌入其中的纤维基质之间的精细结构和关系，每个耳石都有一个紧凑的中心丝芯网络和一个由有序微晶和大分子聚集体组成的复合外壳，20 nm珠状纤维的明显网络覆盖在耳石表面，通过表面黏附和松散的耳锥间纤维基质内的限制将耳石相互连接和固定在凝胶基质上。凝胶基质是由直径22 nm的另一种类型的细丝组成的致密网络，这些细丝通过直径11 nm的较短细丝进行交联。我们的冷冻蚀刻数据为研究耳锥复合体成分的分子性质、它们的机械性能以及耳锥生物合成的生物与化学控制程度提供了一个结构框架，(C)2000学术出版社。
A unique feature of the vertebrate gravity receptor organs, the saccule and utricle, is the mass of biomineral structures, the otoconia, overlying a gelatinous matrix also called "otoconial membrane" on the surface of the sensory epithelium. In mammals, otoconia are deposits of calcium carbonate in the form of composite calcite crystals. We used quick-freezing, deep etching to examine the otoconial mass of the guinea pig utricle. The deep-etching step exposed large expenses of intact and fractured otoconia, showing the fine structure and relationship between their internal crystal structure, their surface components, and the filament matrix in which they are embedded, Each otoconium has a compact central core meshwork of filaments and a composite outer shell of ordered crystallites and macromolecular aggregates, A distinct network of 20-nm beaded filaments covers the surface of the otoconia, The otoconia are interconnected and secured to the gelatinous matrix by surface adhesion and by confinement within a loose interotoconial filament matrix. The gelatinous matrix is a dense network made of yet another type of filament, 22 nm in diameter, which are cross-linked by shorter filaments, characteristically 11 nm in diameter. Our freeze-etching data provide a structural framework for considering the molecular nature of the components of the otoconial complex, their mechanical properties, and the degree of biological versus chemical control of otoconia biosynthesis, (C) 2000 Academic Press.