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Results for “Negative Staining”

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At least 271 records · Page 15Linked to original sources
PubMed1982

The wrapping phenomenon in air-dried and negatively stained preparations.

We demonstrate that the interface energies involved in the direct preparation of supramolecular structures onto supporting films leads very frequently to a smooth wrapping of the supporting film around approximately one third to one half of the structure. We conclude that in such cases the structure is more rigid than the supporting film; examples being ribosomes, small viruses and small glass fragments. Other structures are less rigid and become significantly flattened. Complete flattening is frequently observed with empty virus capsids. The sandwich technique, by which a specimen is placed between two supporting films, in general leads to increased flattening. Only in few cases (e.g. ribosomes) are biological particles rigid enough to resist flattening and become wrapped from both sides.

Coliphages↗
PubMed1983

Quantitative evaluation of high-resolution features in images of negatively stained Tobacco Mosaic Virus.

This study investigates the causes of the apparent differences between the optical diffraction pattern of a micrograph of a Tobacco Mosaic Virus (TMV) particle, the optical diffraction pattern of a ten-fold photographically averaged image, and the computed diffraction pattern of the original micrograph. Peak intensities along the layer lines in the transform of the averaged image appear to be quite unlike those in the diffraction pattern of the original micrograph, and the diffraction intensities for the averaged image extend to unexpectedly high resolution. A carefully controlled, quantitative comparison reveals, however, that the optical diffraction pattern of the original micrograph and that of the ten-fold averaged image are essentially equivalent. Using computer-based image processing, we discovered that the peak intensities on the 6th layer line have values very similar in magnitude to the neighboring noise, in contrast to what was expected from the optical diffraction pattern of the original micrograph. This discrepancy was resolved by recording a series of optical diffraction patterns when the original micrograph was immersed in oil. These patterns revealed the presence of a substantial phase grating effect, which exaggerated the peak intensities on the 6th layer line, causing an erroneous impression that the high resolution features possessed a good signal-to-noise ratio. This study thus reveals some pitfalls and misleading results that can be encountered when using optical diffraction patterns to evaluate image quality.

Computers↗
PubMed1985

Comparative electron microscopic studies of single biomolecules negatively stained and freeze-dried metal-shadowed.

This paper deals with the development of physical fixation and contrasting procedures for the electron microscopic structure analysis of isolated biomolecules. It has been shown on isolated antibodies (IgG) that these preparation methods give better preservation of biomolecules than the commonly practiced chemical fixation and staining techniques. With regard to morphology and size, the data from the electron microscopic structure analysis of the tested antibodies (IgG) are in good agreement with those from X-ray structure analysis. With isolated ribosomal 40S subunits, the influence of chemical fixation and staining techniques on both the structure preservation and contrast medium distribution has been demonstrated.

Antibodies↗
PubMed1986

A comparison of negatively stained electron micrographs and projections obtained from single crystal X-ray studies: the lipovitellin complex from lamprey.

The analysis of single crystals of the lipovitellin complex from lamprey has made it possible to compare electron density projections derived from X-ray diffraction and density modification methods with previously published electron micrographs. The close correlation between the images obtained by the two methods demonstrates that the fidelity of images obtained by electron microscopy is excellent despite the loss of specimen order. These correlations also attest to the ability of density modification methods, currently used in macromolecular crystallography, to estimate the phases of small angle X-ray reflections.

Animals↗