The long term objective of this project is to provide faculty at the University of Texas at San Antonio with the needed capabilities for using the UTSA Transmission Electron Microscope Facility in their individual research projects. The specific aims of this proposal are 1) to maximize the capacity of the UTSA Transmission Electron Microscope (TEM) Facility for tissue sectioning; and, 2) to provide assistance to faculty for routine embedding, sectioning and photography in order to increase research productivity at the institution. Electron microscopy provides an invaluable technique for localizing both structures and molecules at the subcellular level. There are currently a number of faculty in the Division of Life Sciences at the University of Texas at San Antonio who use, or plan to use, electron microscopy in their research. To accomplish the specific aims of the present proposal, the capacity of the UTSA TEM Facility will be increased by purchasing a rotary microtome. In addition, assistance will be provided for the following routine tasks: tissue fixation, tissue embedding, thick sectioning, thin sectioning, sample analysis, photography and printing. With the increased capacity and available technical assistance, faculty will be able to complete ultrastructural studies in a timely fashion. thereby increasing their research capabilities, and, ultimately, their research productivity.