| Abstract: | Tomography is a powerful tool for obtaining three-dimensional information from transmission electron microscopy, but its application faces unique challenges. A single-axis tilt geometry for data collection results in anisotropic resolution because full angular coverage is not feasible for most specimen preparations. This effect can be minimized by combining two single-axis tilt series that have been collected orthogonal to each other. Rapid freezing has been successfully used to preserve the native structure of biological specimens in a form that can be visualized in the high-vacuum environment required for electron microscopy; however, these preparations are extremely labile to electron exposure. As a result, application of tomography to frozen-hydrated specimens has only recently become feasible with the development of automatic data collection, and with a renewed appreciation for the principle of dose fractionation. Even with the limitations of traditional specimen preparations and conventional methods of data collection, electron microscopic tomography has been successfully employed to probe the structure and function of several important cellular components. Current efforts include combining electron microscopic tomography and video-enhanced light microscopy to correlate ultrastructural variation with the direction of chromosome motion during mitosis. © 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 175–187, 1997 |
