Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Negative Staining”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1976

Contrast enhancement of negatively stained macromolecules and biomembranes by single sideband phase contrast interference.

A straightforward procedure is described for the production of contrast enhancement of negatively stained macromolecules and biological membranes by single sideband phase contrast interference (electron optical shadowing). The instrumental adjustment required to produce this type of phase contrast illumination is readily achieved by beam deflection from the strioscopic (dark field) mode. Part of the hollow cone of electrons from the annular condenser aperture that are unscattered by the specimen are permitted to pass through the objective aperture and interfere with the scattered beam. The electron optical shadowing effect is produced because only one side of the unscattered beam is used. Careful adjustment of the beam tilt control, with the ability to tilt in any azimuth, allows optimal illumination conditions to be achieved. The results presented show the increased image contrast obtained using as specimens the purified cylindrical macromolecule from human erythrocyte membranes, purified nuclear envelopes and collagen fibres.

Animals↗
PubMed1984

Electron microscopic observation on the developing rabbit and human vitreous collagen fibrils by negative staining.

The vitreous fibrils of developing eyes of 3-day-old rabbits and 24th week human fetuses were examined by the negative staining method (phosphotungstic acid) electron microscopically. Fibrils about 10 nm in diameter and with no periodic striated pattern as well as adult ones were observed. Peculiar fibers were observed in both vitreous samples preserved at low temperature. Particularly, dimeric segment-long-spacing (SLS) aggregates and fibrous-long-spacing (FLS)-like aggregates were observed in 3-day-old rabbit vitreous. FLS-like aggregates showed a 125-nm light band and 50-nm dark band periodic pattern and seemed to be formed with 300-nm overlapping of dimeric SLS aggregates. The present results indicate that the developing vitreous could possibly form various types of collagen fiber under native conditions.

Adult↗
PubMed1991

Circular harmonic averaging of rotary-shadowed and negatively stained creatine kinase macromolecules.

The structure of mitochondrial creatine kinase is investigated by high-resolution shadowing at very low temperature and conventional negative staining. The electron microscopic images are analyzed with circular harmonic averaging, a method suited for the processing of single molecules. The rotational alignment and averaging is performed with the circular harmonic components, which allows data compression and several steps of noise reduction to be carried out within the averaging procedure. In addition, the symmetry can be deduced. For the mitochondrial creatine kinase, a fourfold symmetry is found that is compatible with the biochemical and biophysical characterization of the molecule.

Creatine Kinase↗
PubMed1991

Demonstration of Epstein-Barr virus in scrape material of lateral border of tongue in heart transplant patients by negative staining electron microscopy.

Scrape material from the lateral border of the tongue of 50 heart transplant patients and 20 controls was studied for the presence of EBV by negative staining electron microscopy. Mild oral hairy leukoplakia was observed in two cases. Particles of the herpes virus were found in 20% of the specimens. Controls were negative for EBV. The study has shown that EBV may be expressed at the lateral border of the tongue during immunosuppression, occasionally resulting in the clinical appearance of hairy leukoplakia.

Adult↗
PubMed1983

Study of negatively stained images of Sendai virus nucleocapsids using minimum-dose system.

Using minimum-dose system and optical diffraction, effects of electron irradiation on negatively stained images of trypsin-straightened nucleocapsids of Sendai virus were semiquantitatively compared for uranyl-acetate (UA) and phosphotungstic acid (PTA). The results confirmed the superiority of UA in display of fine structures and showed that both UA- and PTA-stained images tended to turn from a one-sided to a two-sided image during irradiation, the general contrast of the picture increased in the UA-stained images but not in the PTA-stained ones, and furthermore the electron doses for the richest information were 18 000 to 30 000 e-/nm2 for UA, but 1000 e-/nm2 for PTA, under the condition used. The optical diffraction patterns of the UA-stained nucleocapsids, its analysis by the superposition method, and rotational harmonics of end-on views of nucleocapsids, together indicated that the most probable arrangement of subunits was 13 per turn of a helix with 5-nm periodicity. This helix also had an arrangement of subunits parallel to the axis. The occurrence of 2.5 nm periodicity was probably produced by an arrangement of a UA-penetrable concave substructure of the subunit.

Capsid↗
PubMed1991

Cryoultramicrotomy of muscle: improved preservation and resolution of muscle ultrastructure using negatively stained ultrathin cryosections.

Ultrathin sections of rapidly frozen, briefly pre-treated muscle tissue are cut and thereafter are thawed and contrasted using a negative staining technique. The method has provided micrographs in which the in-vivo order in the muscle fibres has been preserved well enough to enable both a more complete interpretation of X-ray diffraction evidence from muscle, and also a gain of new ultrastructural information on aspects of myofibril and myofilament architecture in different types of fibre. Examples here are taken from chicken, rabbit and fish muscles and show both the M-band and the bridge region of the A-band in great detail. To enhance the detail in the original images, one-dimensional (1-D) and 2-D averaging techniques (lateral smearing and step averaging, respectively) are used. Although there is major shrinkage in section thickness to about one-third of its original value, demonstrated here for the first time is the fact that the characteristic A-band lattice planes are preserved in these sections in 3-D. This confirms the usefulness of cryosections not just for 1-D and 2-D image processing, but also for 3-D reconstruction. Thus, in combination with techniques of image processing, cryoultramicrotomy can give the muscle morphologist the detailed data that are needed to match the molecular biologists, biochemists and immunologists in the interpretation of their data about physiological and pathophysiological events in muscle fibres at the macromolecular level.

Animals↗
PubMed1979

Ultrastructure of rat renal tubular basement membrane--meshwork structure demonstration by negative staining.

The tubular basement membrane (TBM) (i.e. tubular basal lamina) of rat kidney was shown to be a fine meshwork by electron microscopy after negative staining. Strands of the meshwork formed a regular three dimensional lattice work. The pores of the meshwork were polygonal. There were two main pore sizes: one approximately 30 A in diameter, the other 42--60 A. In view of our previous observation that glomerular and alveolar basement membranes were made up fine meshwork, it is quite possible that the basement membranes of other organs are also made up such fine meshwork.

Animals↗
PubMed1984

Dynamical electron scattering from negatively stained protein microcrystals.

Multislice n-beam dynamical calculations have been carried out at 20 and 15.6 A resolution to simulate the electron scattering from a negatively-stained protein microcrystal using a model based on the crystal structure of E. coli matrix porin. Images at t = 100 A, i.e. the thickness of reconstituted vesicle preparation, correspond to the projected potential of the kinematical structure. The kinematical model is valid at least to t = 500 A, beyond which the projected-image symmetry does not correspond to the actual structure. If a crystallographic residual limit R = 0.20 is imposed, the electron diffraction intensity data correspond to the kinematical data up to t = 700 and 1000 A, respectively, for 15.6 and 20 A resolution.

Computers↗
PubMed1987

Effects of two negative staining methods on the Chinese atypical rotavirus.

The Chinese atypical (Group B) rotavirus, previously called the adult diarrhoea rotavirus (ADRV), was examined by transmission electron microscopy using either uranyl acetate or potassium phosphotungstate (PTA) as negative stains. Complete rotavirus particles were seen using uranyl acetate which were indistinguishable morphologically from typical rotaviruses. In the same preparations virus particles with differing degrees of degradation were seen after staining with PTA. This effect was not related to pH of the PTA and could be prevented by fixation of the specimen by 0.1 per cent glutaraldehyde. It is concluded that the use of PTA can give rise to falsely negative results for specimens containing this virus.

Glutaral↗
PubMed1983

Length and appearance of projections on neuronal microtubules in vitro after negative staining: evidence against a crosslinking function for MAPs.

The length and appearance of microtubule-associated proteins (MAPs) on microtubules reconstituted in vitro have been investigated by the negative-staining technique. We found that uranyl acetate (UA) causes the normally extended MAPs on microtubules to coil up into globular projections 7-10 nm in length. This perturbation occurred if the microtubules reacted with UA before they became adsorbed to the grid surface. If the microtubules were adsorbed to the grid surface before staining, the MAPs remained as extended, filamentous molecules, 35-40 nm in length. Glutaraldehyde also caused MAPs to coil into globular structures. In the altered, globular configuration, MAPs served to crosslink pairs of microtubules. In the normal filamentous configuration, MAPs were never seen to crosslink pairs of microtubules. Therefore, we concluded that MAPs do not function as crosslinking proteins between microtubules.

Animals↗
PubMed1977

[Contagious ecthyma with virus demonstration in a negative staining method].

The diagnosis of contagious ecthyma was presumed by history and clinical appearance in a 33-year-old farmer. In electron miscroscopical preparations viral particles were found by the negative staining method. It is proposed to use this method for rapid diagnosis of suspected cases. In old lesions it is more difficult to demonstrate viral particles than in fresh lesions. Differential diagnosis and the position of Orf-virus in the system of viruses are briefly discussed.

Adult↗
PubMed1989

Electron microscopy of negatively stained scallop myosin molecules. Effect of regulatory light chain removal on head structure.

The heads of myosin molecules from the striated adductor muscle of scallop have been studied by electron microscopy after negative staining. In common with vertebrate skeletal muscle myosin visualized by this method, the scallop myosin heads were pear-shaped and often showed pronounced curvature. Staining suggestive of two or, more frequently, three domains could often be observed. Removal of regulatory light chains (R-LCs) resulted in a reduction in the length of the heads of about 2.6 nm, with no significant change in maximum width. In desensitized preparations a majority of heads displayed anticlockwise curvature, whereas intact heads were usually seen curved clockwise. Analysis of the head curvature in both intact and desensitized molecules was consistent with an ability of each head to rotate about its long axis. Desensitization resulted in an increased incidence of heads showing two domains. It seems likely that the reduction in length upon removal of the R-LC is due to the two small domains located in the neck region of the head collapsing into one.

Animals↗
PubMed1980

Spatial filtering of electron micrographs of negatively stained alpha-amylase crystals.

Images of the alpha-amylase molecule from pig pancreas have been obtained in two projections by the application of spatial filtering techniques to electron micrographs of negatively stained microcrystals of the enzyme. The Fourier filtering was performed on a PPD 11/40 digital computer after microdensitometry on an Optronics P-1000 photoscan system. The set of procedures and programs we employed are described herein. We compared these images with equivalent images obtained by three-dimensional X-ray diffraction analysis using conventional isomorphous replacement at approximately twice the resolution. We find that there is quite good agreement between the two kinds of images, and that a number of gross structural features compare quite well. We conclude that the combination of electron microscopy with digital spatial filtering when applied to protein microcrystals yields very respectable results.

Amylases↗
PubMed1983

An ultrastructural investigation of the filamentous surface appendages of suspensions of plaque bacteria as revealed by negative staining.

The filamentous surface appendages of freshly-collected aqueous suspensions of plaque bacteria, obtained from 1 day old supragingival plaque have been examined in the electron microscope by the technique of negative staining with methylamine tungstate. Approximately half of the bacteria revealed surface appendages as either fimbriae (45%), flagella (13%) or both (3%). The appendages were distributed either polarly, intermittently or peri-trichously around the bacteria and varied in length from 0.2 micron to more than 20 micron. It was not possible from these observations alone to determine either the topology of the appendages or their role as they existed originally in dental plaque.

Bacteria↗
PubMedDate not supplied

Effect of succinylation on images of negatively stained arrays of mitochondrial outer membrane channels.

The voltage-dependent anion-selective channels of the outer membrane of Neurospora mitochondria occur in two-dimensional crystalline arrays. Electron microscopic images of negatively stained arrays have been compared for normal membranes and membranes pretreated with succinic anhydride, which changes the functional characteristics of the channel. Succinic anhydride does not alter the lattice parameters or the long-range order in the arrays. Also, it has no significant effect on correlation averages of channel arrays embedded in uranyl acetate. Thus, functional changes induced in the channel by succinic anhydride are probably not due to large-scale conformational changes. The distribution of the anionic stain phosphotungstate on the mitochondrial channel arrays is significantly altered by succinic anhydride pretreatment. There are loci on the channels of reduced phosphotungstate accumulation following succinylation. Since phosphotungstate selectively stains positively charged amino acids, it is proposed that these loci may represent clusters of functionally important, exposed basic amino acids.

Anions↗
PubMed1996

Negative-Stain Immunoelectron-Microscopic Analysis of Small Macromolecules of Immunologic Significance

We have demonstrated that unlabeled antibodies or their antigen-reactive fragments, Fab and F(ab')2, can be readily visualized by negative-stain immunoelectron microscopy and can be quite useful as probes for detailed epitope mapping and structural analysis of relatively small macromolecules. In addition, information on segmental flexibility of the target molecules can be deduced as can information on the geometry and kinetics of immune complex formation in solution. The various target molecules used to illustrate these points include IgG, IgM, C-reactive protein, and complement receptor 1.

Journal Article↗
PubMedDate not supplied

The ultrastructural disruption of the glomerular basement membrane in diabetic nephropathy revealed by "tissue negative staining method".

To clarify the ultrastructural changes of the glomerular basement membrane (GBM) in diabetic nephropathy, the renal tissues of the patients with diabetic nephropathy were examined by electron microscopy using our newly devised "tissue negative staining method." A fine meshwork structure consisting of fibrils forming the small pores are observed in the normal human GBM. The diameter of these pores was slightly smaller than that of human albumin molecules. The GBM in patients with diabetic nephropathy showed irregular thickening. At higher magnification, cavities and tunnel structures, which were not seen in normal controls, were observed in the thickened GBM. As the diameters of the cavities and tunnels were far larger than the dimensions of albumin molecules, these enlarged structures are considered to allow serum protein molecules to pass through the GBM from the capillary lumen to the urinary space. The present results suggest that the cause of massive proteinuria in diabetic nephropathy is the disruption of the size barrier of the GBM.

Basement Membrane↗
PubMed1993

Ultrastructural changes of the glomerular basement membrane in diabetic nephropathy revealed by newly devised tissue negative staining method.

In order to clarify the mechanism of proteinuria in diabetic nephropathy, ultrastructural changes of the glomerular basement membrane (GBM) in patients with diabetic nephropathy were examined by electron microscopy using our newly devised "tissue negative staining method". The normal human GBM showed a fine meshwork structure consisting of fibrils forming the small pores. The diameter of these pores was slightly smaller than that of human albumin molecules. The GBM in patients with diabetic nephropathy showed irregular thickening. At higher magnification, hitherto unknown cavities and tunnel structures, which were not seen in normal controls, were observed in the thickened GBM. In some portions, these cavities presented a honeycomb-like appearance. The diameters of the cavities and tunnels were far larger than the dimensions of albumin molecules. These enlarged structures are believed to allow serum protein molecules to pass through the GBM from the capillary lumen to the urinary space. These results suggest that the cause of massive proteinuria in diabetic nephropathy is the disruption of the size barrier of the GBM.

Basement Membrane↗