MICROSCOPY Vol.47▶No.2 2012
â– Lecture

Three-Dimensional Reconstruction Techniques for Electron Microscopy and Life Science

Takuo Yasunaga and Ryuzo Azuma

Abstract: Organisms are composed of cells as a unit, which are made of macromolecules, such as proteins, nucleotides and lipids. Their assembly/disassembly such as cytoskeleton or bindings with small ligands are related to physical and/or chemical reactions in the cells, which are essential for life activities. Since the size of them is around nm to micrometer, light microscopy has little ability to observe their structure in the cells directly. Transmission electron microscopy gives us their two-dimensional images at nanometer resolutions but they are projected one. Thus, it is difficult to identify their three-dimensional structure due to their overprint. Even though a very thin section is observed, its thickness is far larger than that of proteins and so their three-dimensional information is hidden. We, therefore, need to restore their 3D structures by three-dimensional electron microscopy to identify them clearly. We here describe the principles of the three-dimensional reconstruction techniques from TEM images and their attentions.

Key words: electron microscopy, three-dimensional reconstruction, electron computed tomography, single particle analysis, projection images