MINERAL MATRIX RELATIONS IN CALCIFYING TISSUES

这项申请的长期目标是获得新的信息 脊椎动物骨骼组织的组织和化学成分：骨， 软骨和肌腱。正常组和正常组的钙化研究 异常样本将检查矿物晶体和 细胞外基质和胶原蛋白、囊泡和 某些磷酸化蛋白质在矿物成核、生长和 发展。矿化作用将首先在正常雏鸟身上进行研究， 大鼠、小鼠和火鸡作为脊椎动物模型系统 异常钙化包括软骨病，骨质疏松症， 钙质疏松症和骨化症。超微结构，生化， 将应用免疫细胞化学和生物物理方法来确定 矿物和有机基质的存在、性质、位置和关系 各组织中的成分。具体地说，假设是 测试结果是：某些位于胞外有机物质中的磷蛋白 脊椎动物组织的基质是矿物质沉积所必需的 在钙化中。这些磷蛋白与胶原蛋白有关 和/或胞外小泡以提供关键的成核位置 矿物形成。矿物质的生长和发育 成核受到立体化学和物理化学的严格控制。 约束条件。检验这一假说的准确目标是1) 大分子立体化学在钙化体系中的表征 胶原纤维及其空间和结构关系 使用常规和高密度的磷蛋白或胞外小泡 电压电子显微镜、三维计算机图像 重建、显微断层扫描和模拟视频技术；2) 通过电子识别矿物沉积的微观位置 衍射-暗场成像，高分辨率电子探针 微量分析和地形成像与常规和 无水样品制备和3)确定空间和时间 矿物质和磷蛋白、胶原蛋白等之间的相互作用 有机基质成分通过上述成像的相互关系 方法：研究方法。这些数据将有助于了解正常结构， 细胞和细胞外的组织和生理功能 脊椎动物成矿组织基质与基本事件 钙化。

The long term objective of this application is to obtain new information of the organization and chemistry of vertebrate skeletal tissues: bone, cartilage, and tendon. Investigation of calcification in normal and abnormal samples will examine interaction between mineral crystals and extracellular matrix and the precise role of collagen, vesicles, and certain phosphorylated proteins in mineral nucleation, growth and development. Mineralization will be studied initially in normal chicks, rats, mice, and turkeys as vertebrate model systems and later in examples of abnormal calcification including rickets, osteoporosis, calcergy, calciphylaxis, and osteopetrosis. Ultrastructural, biochemical, immunocytochemical, and biophysical methods will be applied to determine the presence, nature, location, and relation of mineral and organic matrix components in the respective tissues. Specifically, the hypothesis to be tested is: Certain phosphoproteins located in extracellular organic matrices of vertebrate tissues are required for the deposition of mineral in calcification. These phosphoproteins are associated with collagen and/or extracellular vesicles to provide critical nucleation sites for mineral formation. Growth and development of mineral subsequent to nucleation is under strict control of stereochemical and physicochemical constraints. The precise aims for examining this hypothesis are to 1) characterize in the calcifying systems the macromolecular stereochemistry of collagen fibrils and their spatial and structural relationship with phosphoproteins or extracellular vesicles using conventional and high voltage electron microscopy, three-dimensional computer image reconstruction, microscopic tomography, and simulated video techniques; 2) identify microscopic sites of mineral deposition through electron diffraction-dark field imaging, high resolution electron probe microanalysis, and topographic imaging in conjunction with conventional and anhydrous sample preparation and 3) determine the spatial and temporal interaction between mineral and phosphoproteins, collagen, and other organic matrix constituents through correlation of the above imaging methods. The data will contribute to knowledge of normal structure, organization, and physiological functions of cells and extracellular matrices of mineralizing tissues and fundamental events of vertebrate calcification.