Belnap D M, Grochulski W D, Olson N H, Baker T S
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
Ultramicroscopy. 1993 Mar;48(3):347-58. doi: 10.1016/0304-3991(93)90110-j.
Accurate magnification calibration for transmission electron microscopy is best achieved with the use of appropriate standards and an objective calibration technique. We have developed a reliable method for calibrating the magnification of images from frozen-hydrated specimens. Invariant features in radial density plots of a standard are compared with the corresponding features in a "defocused" X-ray model of the same standard. Defocused X-ray models were generated to mimic the conditions of cryo-electron microscopy. The technique is demonstrated with polyoma virus, which was used as an internal standard to calibrate micrographs of bovine papilloma virus type 1 and bacteriophage phi X174. Calibrations of the micrographs were estimated to be accurate to 0.35%-0.5%. Accurate scaling of a three-dimensional structure allows additional calibrations to be made with radial density plots computed from two- or three-dimensional data.
透射电子显微镜的精确放大倍数校准最好通过使用适当的标准物和客观校准技术来实现。我们已经开发出一种可靠的方法来校准来自冷冻水合标本图像的放大倍数。将标准物径向密度图中的不变特征与同一标准物的“散焦”X射线模型中的相应特征进行比较。生成散焦X射线模型以模拟冷冻电子显微镜的条件。该技术通过多瘤病毒进行了演示，多瘤病毒被用作内标来校准1型牛乳头瘤病毒和噬菌体φX174的显微照片。显微照片的校准估计精确到0.35%-0.5%。三维结构的精确缩放允许使用从二维或三维数据计算出的径向密度图进行额外的校准。
