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At least 217 records · Page 12Linked to original sources
PubMed1970

Isolation of the plasma membrane of the luminal surface of rat bladder epithelium, and the occurrence of a hexagonal lattice of subunits both in negatively stained whole mounts and in sectioned membranes.

A method of isolating the thick luminal membrane from homogenates of bladder epithelium is described, which entails pretreatment of the epithelium with fluorescein mercuric acetate and centrifugation of the homogenate on sucrose density gradients. A hexagonal array of hexamers is illustrated by negative contrast staining in whole mounts of the isolated thick membrane. Subunits are also shown in tangential sections of this thick membrane, in fixed, embedded bladder epithelium. The significance of the subunits is discussed in the context of membrane structure and permeability.

Acetates↗
PubMed1988

Glomerulonephropathy with amyloid-stain-negative microfibrillar glomerular deposits.

A 44-year-old man demonstrated proteinuria, microhematuria and renal dysfunction during the course of hyperthyroidism. Neither cryoglobulinemia nor paraproteinemia including light chains was found. No systemic signs suggestive of amyloidosis appeared. Histological findings showed a diffuse mesangial matrix increase with slight mesangial proliferation and diffuse granular depositions of IgG, IgA, C3, C4, Clq, kappa and lambda light chains. Ultrastructurally, microfibrils of about 20 nm in width were seen to be deposited diffusely in mesangial areas and in glomerular basement membranes. Congo red and thioflavin T staining were negative. These findings support the possible existence of a specific glomerular disease different from amyloidosis.

Adult↗
PubMedDate not supplied

Proteome analysis of polyacrylamide gel-separated proteins visualized by reversible negative staining using imidazole-zinc salts.

Identification and characterization of proteins isolated from natural sources by polyacrylamide gel electrophoresis has become a routine technique. However, efficient sample proteolysis and subsequent peptide extraction is still problematic. Here, we present an improved protocol for the rapid detection of polyacrylamide gel-separated proteins, in situ protein modification, proteolytic digestion and peptide extraction for subsequent protein identification and characterization by capillary high-performance liquid chromatography/tandem mass spectrometry. This simple technique employs the rapid imidazole-zinc reverse stain, in-gel S-pyridylethylation and proteolytic digestion of microcrushed polyacrylamide gel pieces with proteases. This technique obviates the need for buffer exchange or gel lyophilisation due to all of the sample manipulation steps being carried out at near neutral pH and thus lends itself readily to automation.

Acrylic Resins↗
PubMed2006

Cationic hydrous thorium dioxide colloids--a useful tool for staining negatively charged surface matrices of bacteria for use in energy-filtered transmission electron microscopy.

BACKGROUND: Synthesis of cationic hydrous thorium dioxide colloids (ca. 1.0 to 1.7 nm) has been originally described by Müller 22 and Groot 11 and these have been used by Groot to stain acidic glucosaminoglycans for ultrastructure research of different tissues by conventional transmission electron microscopy. RESULTS: Synthesis of colloidal thorium dioxide has been modified and its use as a suitable stain of acidic mucopolysaccharides and other anionic biopolymers from bacteria, either as whole mount preparations or as preembedment labels, is described. The differences in stain behavior relative to commonly used rutheniumred-lysine and Alcian Blue electron dense acidic stains has been investigated and its use is exemplified for Pseudomonas aeruginosa adjacent cell wall biopolymers. For the first time thorificated biopolymers, i.e. bacterial outer cell wall layers, have been analysed at the ultrastructural level with electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI), leading to excellent contrast and signal strength for these extracellular biopolymers. CONCLUSION: Application of cationic hydrous ThO2 colloids for tracing acidic groups of the bacterial surface and/or EPS has been shown to be rather effective by transmission electron microscopy. Because of its high electron density and its good diffusibility it stains and outlines electro-negative charges within these biopolymers. In combination with ESI, based on integrated energy-filtered electron microscopy (EFTEM) Th-densities and thus negative charge densities can be discriminated from other elemental densities, especially in environmental samples, such as biofilms.

Animals↗
PubMed1996

Negative staining with zinc-imidazole of gel electrophoresis-separated nucleic acids.

Zinc and imidazole salts were applied for the detection of nucleic acids on either polyacrylamide of agarose gels. After electrophoresis, polyacrylamide gels are washed in distilled water to remove most of the residual electrophoresis reagents, then incubated in 10 mM zinc sulfate for 10 min, and subsequently immersed in 0.2 M imidazole for 3 min. As a result, zinc salts precipitate on the gel surface, except in the positions occupied by nucleic acids, which appear as transparent, colorless bands. Staining of nucleic acids on agarose gels can be performed by incubation in 40 mM zinc sulfate for 10 min, followed by immersion in 0.2 M imidazole for 5 min to form a deep white-stained background. On soaking in 2 M imidazole for 45 min, the imidazole-induced zinc precipitate is removed from the positions were nucleic acids are located resulting in a negative image of colorless and transparent nucleic acid bands against a white background. The sensitivity of this stain ranges from 5 to 7 ng/band for small (from 1 to 0.2 kbp) DNA, from 7.8 to 13 ng/band for different 22-base oligonucleotides, from 62 to 125 ng/band for large (from 20 to 2 kbp) DNA, and is 1 microgram/band for human peripheral-blood monocyte RNA. After chelation of zinc with EDTA, the nucleic acids can be quantitatively recovered from the gel. The principal advantage of this technique over ethidium bromide staining is evident for preparative purposes. Using zinc-imidazole in the detection of purified pBACIB.1 (2.8 kbp) plasmid DNA and anti-HBsAg single chain Fv antibody fragment (0.7 kbp) DNA, followed by elution from gel slices, ligation and transformation of competent E. coli XL-1 Blue cells, the number of transformants notably increased from 280 (obtained with conventional ethidium bromide staining plus UV-irradiation at 312 nm) to 10,000.

Antibodies, Viral↗