Search results for "Uranyl acetate"
showing 8 items of 8 documents
Keyhole limpet haemocyanin: negative staining in the presence of trehalose
1995
Abstract Samples of unpurified and purified haemocyanin from the giant keyhole limpet Megathura crenulata have been studied by transmission electron microscopy (TEM) using mixtures of trehalose with the negative stains, uranyl acetate and ammonium molybdate. Trehalose is a known protein preservative during air and freeze drying, UV irradiation and high temperatures, and therefore offers the possibility of protecting proteins during the drying of negatively-stained specimens and their subsequent electron microscopical study. Evidence is presented that trehalose possesses satisfactory stability within the electron beam during conventional room temperature, negative-staining studies. The combi…
Negative Staining and Cryo-negative Staining: Applications in Biology and Medicine
2013
Negative staining is widely applicable to isolated viruses, protein molecules, macromolecular assemblies and fibrils, subcellular membrane fractions, liposomes and artificial membranes, synthetic DNA arrays, and also to polymer solutions and a variety of nanotechnology samples. Techniques are provided for the preparation of the necessary support films (continuous carbon and holey/perforated carbon). The range of suitable negative stains is presented, with some emphasis on the benefit of using ammonium molybdate and of negative stain-trehalose combinations. Protocols are provided for the single droplet negative staining technique (on continuous and holey carbon support films), the floating a…
Cholesterol binding to amyloid-β fibrils: A TEM study
2008
There is increasing interest in the role of brain cholesterol in Alzheimer's disease and the contribution of cholesterol to the formation of amyloid plaques. This paper presents a TEM study showing the binding of soluble approximately 10 nm diameter cholesterol-PEG 600 micelles to amyloid-beta(1-42) (Abeta(1-42)) fibrils formed either in the presence of this cholesterol derivative or to preformed fibrils generated under four different fibrillogenesis conditions. Specimens negatively stained with uranyl acetate revealed that during 24 h fibrillogenesis at 37 degrees C the cholesterol-PEG micelles bound periodically to Abeta(1-42) protofibrils and apparently also formed a thin smooth unbroken…
Double-Shell Vesicles, Strings of Vesicles and Filaments Found in Crosslinked Micellar Solutions of Poly(1,2-butadiene)-block-poly(ethylene oxide) Di…
2001
Micellar structures of amphiphilic poly(1,2-butadiene)-block-poly(ethylene oxide) diblock copolymers have been crosslinked in aqueous solution by γ-irradiation. By transmission electron microscopy (TEM) of neganively stained specimen it is shown that the precominant structures present are sopolymer sesicles (which appear to be double latered. These fived vesules are stable with respect to their share and can be transferred from water into a good solvent for blue filbeks, such as tetrahydrofuran, this demonstrating the effectiveness of the crosslinking. In addition to the resicles a small number of flexible cylindrichl/filimented structures sequentially fused vesicles/strings of vesicles and…
Alkaline hydrolysis/methylation-acetylation: a new technique for ultrastructural DNA cytochemistry.
1991
SUMMARY A new technique for the visualization of DNA-containing structures in electron microscopy is described. Samples of glutaraldehyde-fixed bone marrow from rats were subjected to alkaline hydrolysis to remove RNA and the phosphate of phospho-proteins, followed by a combined blockage of protein carboxyl and amino groups through methylation-acetylation. After uranyl acetate staining of epoxy-embedded ultrathin sections, chromatin from all cell types showed a highly selective and intense electron opacity. Staining methods for DNA were also positive in semithin sections. This simple procedure could be very useful in ultrastructural cytochemistry of DNA and chromatin.
Influence of saline and pH on collagen type I fibrillogenesis in vitro: Fibril polymorphism and colloidal gold labelling
2007
We have produced different collagen type I fibrils by in vitro fibrillogenesis of acetic acid-soluble collagen within the pH range 2.5-9.0, in the presence and absence of 150 mM NaCl. The varying relatively stable molecular assemblies and polymorphic fibrillar end-products produced after 24 h incubation have been assessed and compared by the TEM study of specimens negatively stained with uranyl acetate. In the presence of 150 mM NaCl, the assembly of collagen at low pH (2.5) leads to the formation of initial molecular aggregates that progressively link together at slightly higher pH (5.0) to form sub-fibrils and spindle-shaped D-banded bundles of sub-fibrils. At pH 6.0 these D-banded bundle…
Negative Staining of Thinly Spread Biological Samples
2007
Negative staining is widely applicable to isolated viruses, protein molecules, macro-molecular assemblies and fibrils, subcellular membrane fractions, liposomes and artificial membranes, synthetic DNA arrays, and also to polymer solutions. In this chapter, techniques are provided for the preparation of the necessary support films (continuous carbon and holey/perforated carbon). The range of suitable negative stains is presented, with some emphasis on the benefit of using ammonium molybdate and of negative stain-trehalose combinations. Protocols are provided for the single-droplet negative staining technique (on continuous and holey carbon support films), the negative staining-carbon film te…
The structure of gas-filled n-butyl-2-cyanoacrylate (BCA) polymer particles
1995
Abstract The structure of gas-filled poly-[n-butyl-2-cyanoacrylate] (BCA) particles has been demonstrated by negative staining with uranyl acetate, platinum-carbon shadowing of air-dried material and thin sectioning of the aqueous suspension of BCA particles, embedded in water-soluble melamine resin. The polymer shell of the hollow particles possesses a globular outer surface and a smoother inner surface.