title: Magnification calibration and the determination of spherical virus diameters using cryo-microscopy.
abstract: The diameters of several frozen-hydrated, spherical viruses were determined using polyoma virus as either an external or an internal calibration standard. The methods described provide a reproducible and accurate way to calibrate microscope magnification. The measured diameters are in excellent agreement with respective measurements previously reported for aqueous samples at room temperature using X-ray diffraction methods. These results indicate that the native morphology and dimensions of biological macromolecules are better preserved in frozen-hydrated samples when compared with more conventional electron microscopy techniques such as negative-staining, metal shadowing or thin-sectioning.
authors: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
authors: N H
authors: NH
authors: Olson
authors: T S
authors: TS
authors: Baker
mesh_terms: D002138:Calibration; D005615:Freezing; D008854:Microscopy, Electron / Q000379:methods*; D010316:Particle Size; D011309:Preservation, Biological; D015203:Reproducibility of Results; D014771:Virion / Q000648:ultrastructure; D014780:Viruses / Q000648:ultrastructure*