Acquistion of a High-Pressure Freezing/Freeze Substition System for Electron Tomography and Immunocytochemistry

该合同部分支持为芝加哥大学的电子显微镜(EM)核心设备购买高压冷冻和冷冻替代仪器。这项技术将使生物学家能够利用免疫细胞化学和电子断层扫描的最新发展进行先进的EM。与标准的醛固定相比，冷冻固定具有在毫秒内固定细胞结构的优点，从而避免了常见的固定伪影，如形状变化和膜融合。冷冻固定对于免疫细胞化学是有用的，因为结构可以被很好地保存而不会失去抗原性。在高压下进行冷冻固定，可以冻结相对较厚的样品，而不会受到冰晶形成的破坏。这种方法特别适用于电子断层扫描，它使生物结构能够以纳米分辨率重建三维。近年来，电子断层扫描已成为研究细胞器重塑、膜运输和有丝分裂纺锤体动力学等细胞过程的有力工具。芝加哥大学的几名研究人员与其他机构的研究小组合作，对酵母、原生生物和哺乳动物细胞进行高压冷冻和/或电子断层扫描，这里的其他细胞生物学和生理学研究人员需要这些技术来回答紧迫的科学问题。新技术的用户将包括大学实验室的博士后、研究生和本科生，以及访问大学进行暑期研究实习的本科生。芝加哥或邻近地区还没有高压冷冻系统，所以所要求的系统对附近机构的研究人员来说也是一个有价值的补充。此外，新的设备和方法将纳入研究生和本科生的课堂教学。

This award partially supports the acquisition of a high-pressure freezing and freeze substitution instruments for the electron microscopy (EM) Core facility at the University of Chicago. This technology will allow biologists to perform advanced EM by taking advantage of recent developments in immunocytochemistry and electron tomography. Compared to standard aldehyde fixation, cryofixation has the advantage of immobilizing cellular structures within milliseconds, thereby avoiding common fixation artifacts such as shape changes and membrane fusion. Cryofixation is useful for immunocytochemistry because structure can be well preserved without loss of antigenicity. Performing cryofixation at high pressures allows relatively thick samples to be frozen without being damaged by ice crystal formaton. This method is particularly appropriate for electron tomography, which enables biological structures to be reconstructed in three dimensions at nanometer resolution. In recent years, electron tomography has become a powerful tool for studying cellular processes such as organelle remodeling, membrane trafficking, and mitotic spindle dynamics. Several researchers at the University of Chicago have collaborated with groups at other institutions to perform high-pressure freezing and/or electron tomography of yeast, protist, and mammalian cells, and other cell biology and physiology researchers here need these techniques to answer pressing scientific questions. Users of the new techniques will include postdocs, graduate students, and undergraduates in University labs, as well as undergraduates who visit the University for summer research internships. High-pressure freezing has not been available in Chicago or the immediate vicinity, so the requested system will also be a valuable addition for researchers at nearby institutions. In addition, the new equipment and methods will be incorporated into classroom teaching at the graduate and undergraduate levels.