• Applied Microscopy
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• 제47권4호
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• pp.223-225
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• 2017

Cryo-electron microscopy (cryo-EM) is arguably the most powerful tool used in structural biology. It is an important analytical technique that is used for gaining insight into the functional and molecular mechanisms of biomolecules involved in several physiological processes. Cryo-EM can be separated into the following three groups according to the analytical purposes and the features of the biological samples: cryo-electron tomography (cryo-ET), cryo-single-particle reconstruction, and cryo-electron crystallography. Cryo-tomography is a unique EM technique that is used to study intact biomolecular complexes within their original environments; it can provide mechanistic insights that are challenging for other EM-methods. However, the resolution of reconstructed three-dimensional (3D) models generated by cryo-ET is relatively low, while single-particle reconstruction can reproduce biomolecular structures having near-atomic resolution without the need for crystallization unless the samples are large (>200 kDa) and highly symmetrical. Cryo-electron crystallography is subdivided into the following two categories according to the types of samples: one category that deals with two-dimensional (2D) crystalline arrays and the other category that uses 3D crystals. These two categories of electron-crystallographic techniques use different diffraction data obtained from still diffraction and continuous-rotation diffraction. In this paper, we review crystal-based cryo-EM techniques and focus on the recently developed 3D electron-crystallographic technique called microcrystal-electron diffraction.

• Journal of Photoscience
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• 제1권1호
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• pp.63-66
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• 1994

Silver chlorobromoiodide cubic seed emulsion was prepared'in the presence of ammonia and phenylcarbamyl gelatin solution. When benzenethiosulfonate sodium salt (BTS) and 4-hydroxy6-methyl-1,3,3a,7-tetraazaindene (TAI), as growth modifiers, were added in the seed emulsion, the silver halide microcrystals were obtained in the forms of cubo-octahedrons, octahedrons, rhombic dodecahedron by variation of pAg value through controlled double jet. The crystal habits and shapes were determined by means of X-ray diffraction (D/MAX BIB, Rigaku) and electron microscopy (JSM-840, JEOL), respectively.