Abstract
A method is described for the estimation of the true width of fibrillar or rod-like structures from electron micrographs of metal-shadowed preparations. The method is based on variations in the image width as a function of the angle (β) between the long axis of the fibril and the direction of the shadow in the plane of the preparation. The image width when β = 0° practically represents the real width of the elongated particle but is often indistinguishable from the background. The fibril image width is conveniently measured at β values between 15° and 90°. The true width is obtained by plotting the image width versus sin β and extrapolating to β = 0°. Latex spheres are sprayed with the fibrils or rods to indicate the direction of shadow. Tobacco mosaic virus (TMV) was used as a model structure because of its known constant diameter of 150 A (5). The width (in the case of TMV equal to the diameter) found by the present method was 150 A ± 8 A.
Full Text
The Full Text of this article is available as a PDF (477.1 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BEER M., ZOBEL C. R. Electron stains. II: Electron microscopic studies on the visibility of stained DNA molecules. J Mol Biol. 1961 Dec;3:717–726. doi: 10.1016/s0022-2836(61)80076-4. [DOI] [PubMed] [Google Scholar]
- BRENNER S., HORNE R. W. A negative staining method for high resolution electron microscopy of viruses. Biochim Biophys Acta. 1959 Jul;34:103–110. doi: 10.1016/0006-3002(59)90237-9. [DOI] [PubMed] [Google Scholar]
- HALL C. E. Measurement of globular protein molecules by electron microscopy. J Biophys Biochem Cytol. 1960 Jul;7:613–618. doi: 10.1083/jcb.7.4.613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HALL C. E. Method for the observation of macromolecules with the electron microscope illustrated with micrographs of DNA. J Biophys Biochem Cytol. 1956 Sep 25;2(5):625–628. doi: 10.1083/jcb.2.5.625. [DOI] [PMC free article] [PubMed] [Google Scholar]
- OHAD I., DANON I. O., HESTRIN S. Synthesis of cellulose by Acetobacter xylinum. V. Ultrastructure of polymer. J Cell Biol. 1962 Jan;12:31–46. doi: 10.1083/jcb.12.1.31. [DOI] [PMC free article] [PubMed] [Google Scholar]