Search results for "Staining"
showing 10 items of 449 documents
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…
Polymorphism of amyloid-beta fibrils and its effects on human erythrocyte catalase binding.
2009
The Alzheimer's amyloid-beta (Abeta) peptide exists as a number of naturally occurring forms due to differential proteolytic processing of its precursor molecule. Many of the Abeta peptides of different lengths form fibrils in vitro, which often show polymorphisms in the fibril structure. This study presents a TEM based analysis of fibril formation by eighteen different Abeta peptides ranging in length from 5 to 43 amino acids. Spectrophotometric analysis of Congo red binding to the fibrillar material has been assessed and the binding of human erythrocyte catalase (HEC) to Abeta fibrils has also been investigated by TEM. The results show that a diverse range of Abeta peptides form fibrils a…
Negative staining across holes: application to fibril and tubular structures.
2007
The negative staining technique, when used with holey carbon support films, presents superior imaging conditions than is the case when samples are adsorbed to continuous carbon films. A demonstration of this negative staining approach is presented, using ammonium molybdate in combination with trehalose, applied to several fibrillar and tubular samples. Fibrils formed from the amyloid-beta peptide and the protease inhibitor pepstain A spread very well unsupported across holes and the different polymorphic fibril forms can be readily assessed. However, tubular forms of amyloid-beta have a tendency to be flattened, due to surface tension forces prior to and during specimen drying. Sub-fibril a…
Multiplexed plasmon sensor for rapid label-free analyte detection.
2013
Efficient and cost-effective multiplexed detection schemes for proteins in small liquid samples would bring drastic advances to fields like disease detection or water quality monitoring. We present a novel multiplexed sensor with randomly deposited aptamer functionalized gold nanorods. The spectral position of plasmon resonances of individual nanorods, monitored by dark-field spectroscopy, respond specifically to different proteins. We demonstrate nanomolar sensitivity, sensor recycling, and the potential to upscale to hundreds or thousands of targets.
Strategies for the enantiomeric determination of amphetamine and related compounds by liquid chromatography.
2002
This paper summarizes recent research on the stereospecific analysis of amphetamine, its analogs and metabolites, by liquid chromatography. The different methods proposed have been evaluated and compared in terms of resolution power, time of analysis, sensitivity, or potential for automation. Chiral derivatization, followed by separation of the diastereomers formed in achiral chromatographic systems, is still the method preferred for the analysis of amphetamines at trace levels, as derivatization also improves analyte detectability. This is the method of choice for the enantiomeric analysis of amphetamines at the low concentrations typically encountered in biological samples. In recent year…
Characterization of cell wall proteins from yeast and mycelial cells of Candida albicans by labelling with biotin: Comparison with other techniques
1992
Candida albicans ATCC 26555 blastoconidia and blastoconidia bearing germ tubes were metabolically labelled by incubating the cells with 14C-labelled protein hydrolysate and were subsequently tagged with biotin. Double-labelled (radioactive and biotinylated) cell wall proteins and glycoproteins were extracted from intact cells of both growth forms by treatment with 2-mercaptoethanol (beta ME) and with beta-glucanases (Zymolyase) after treatment with beta ME. The beta ME- and Zymolyase-extracts were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotted (immunoblotted) to nitrocellulose paper. Polyacrylamide gels were stained with Coomassie blue and process…
Enterococcal meningitis caused by Enterococcus casseliflavus. First case report
2005
Abstract Background Enterococcal meningitis is an uncommon disease usually caused by Enterococcus faecalis and Enterococcus faecium and is associated with a high mortality rate. Enterococcus casseliflavus has been implicated in a wide variety of infections in humans, but never in meningitis. Case presentation A 77-year-old Italian female presented for evaluation of fever, stupor, diarrhea and vomiting of 3 days duration. There was no history of head injury nor of previous surgical procedures. She had been suffering from rheumatoid arthritis for 30 years, for which she was being treated with steroids and methotrexate. On admission, she was febrile, alert but not oriented to time and place. H…
Detection of Type VII collagen in odontogenic keratocyst: An immunohistochemical study
2019
Background Separation of the epithelial lining from the underlying connective tissue wall has been a frequently observed and unique feature in odontogenic keratocysts (OKC), but not in other odontogenic cysts nor neoplasms. No study on OKC has been reported evaluating the role of type VII Collagen, the anchoring fibrils, which function in stabilising the epithelial structure. The purpose of this study was to assess the role of type VII collagen in the fragility of the epithelium leading to a high recurrence rate in OKCs. Material and Methods Immunohistochemical staining with Abcam® Monoclonal Mouse Anti-Collagen VII Antibody [LH7.2] (used at a dilution of 1:200) on 30 tissues of OKC. The ch…
Stain-free virtual histology of Bombus terrestris compound eyes by laboratory phase-contrast nano-CT
2021
The visual systems of pollinating insects are studied to understand the effects of a changing environment, and are to date imaged using microscopy or micro-CT. Microscopy only allows two-dimensional imaging and conventional micro-CT requires heavy-metal staining of the samples. Here we present virtual histology of compound eyes of bumblebee (Bombus terrestris) using a laboratory nano-CT system. Propagation-based phase-contrast CT allows three-dimensional imaging of samples without using any staining. Micrometre-resolution images of the microanatomy of the eyes were reconstructed, and the features identified in CT (cornea, crystalline cones, pigment, photoreceptor cells, basement membrane) w…
Number III Mucous membrane pemphigoid
2005
Mucous membrane pemphigoid (MMP) is a sub-epithelial vesiculobullous disorder. It is now quite evident that a number of sub-epithelial vesiculobullous disorders may produce similar clinical pictures, and also that a range of variants of MMP exist, with antibodies directed against various hemidesmosomal components or components of the epithelial basement membrane. The term immune-mediated sub-epithelial blistering diseases (IMSEBD) has therefore been used. Immunological differences may account for the significant differences in their clinical presentation and responses to therapy, but unfortunately data on this are few. The diagnosis and management of IMSEBD on clinical grounds alone is impo…