Methods of study(4) Electron cryomicroscopy(电子低温显微术) reduces the risk of seeing artifacts as may be unavoidable by negative staining. High concentrations of virus are rapidly, frozen in liquid ethane(乙烷) while on carbon grids. Electron micrographs can be digitized and three-dimensional reconstruction performed. Resolutions of 9A have been achieved using this method Electron cryomIcroscopy
Electron cryomicroscopy （电子低温显微术） reduces the risk of seeing artifacts as may be unavoidable by negative staining. High concentrations of virus are rapidly, frozen in liquid ethane（乙烷） while on carbon grids. Electron micrographs can be digitized and three-dimensional reconstruction performed. Resolutions of 9A have been achieved using this method. Electron cryomicroscopy Methods of study（4）
Methods of study(5) X-ray diffraction of virus crystals is the ultimate in determining the ultrastructure of virion morphology.(是对病 毒形态和超显微结构分析的主要方法) At present, only simple viruses can be crystallized. More com plex viruses are analyzed by attem pting to form crystals of sub-particular molecules. The X-ray diffraction pattern of the virion particle allows mathematical processing, which can predict the molecular configuration(分子构型) of the virus particle X-ray diffraction
X-ray diffraction of virus crystals is the ultimate in determining the ultrastructure of virion morphology. （是对病 毒形态和超显微结构分析的主要方法）At present, only simple viruses can be crystallized. More complex viruses are analyzed by attempting to form crystals of sub-particular molecules. The X-ray diffraction pattern of the virion particle allows mathematical processing, which can predict the molecular configuration（分子构型）of the virus particle . X-ray diffraction Methods of study（5）
Summarize methods of studying a Negative-staining technique 口 Electron microscopy a Immunoelectron microscopy a Electron cryomicroscopy 口X- ray diffraction
Summarize methods of studying Negative-staining technique Electron microscopy Immunoelectron microscopy Electron cryomicroscopy X-ray diffraction
Three-dimensiona reconstruction of an icosahedrally symmetric virus partic|e.(-个-面 体对称病毒粒子的三维重建
Three-dimensional reconstruction of an icosahedrally symmetric virus particle.(一个二十面 体对称病毒粒子的三维重建)
l3 Virus symmetry (helical THe capsids of virions tend to have one of two symmetries -helical or cuboid Helical symmetry can be loosely described as having a'spiral staircase structure. The structure has an obvious axis down the center of the helix. the subunits are placed between the turns of the nucleic acid. a diagram of such a structure(tobacco mosaic virus)is shown in the left Fig.. Animal viruses with a similar capsid structure include measles, rabies and influenza
Helical symmetry can be loosely described as having a ‘spiral staircase’ structure. The structure has an obvious axis down the center of the helix. The subunits are placed between the turns of the nucleic acid. A diagram of such a structure (tobacco mosaic virus) is shown in the left Fig.. Animal viruses with a similar capsid structure include measles, rabies and influenza. 3. Virus symmetry（helical） The capsids of virions tend to have one of two symmetries ——helical or cuboid