scholarly journals Microtubule system of isolated fish melanophores as revealed by immunofluorescence microscopy.

1978 ◽  
Vol 76 (1) ◽  
pp. 229-236 ◽  
Author(s):  
M Schliwa ◽  
M Osborn ◽  
K Weber
Keyword(s):  
Immunofluorescence Microscopy ◽  
Cold Treatment ◽  
Enzymatic Digestion ◽  
Surrounding Tissue ◽  
Moderate Intensity ◽  
Electron Microscopic ◽  
Large Numbers ◽  
Glass Cover Slip ◽  
Electron Microscopic Data ◽  
Pterophyllum Scalare

The microtubule system of melanophores of the angelfish, Pterophyllum scalare, has been studied using antibodies prepared against purified porcine brain tubulin in indirect immunofluorescence microscopy. Melanophores were freed from the surrounding tissue components of isolated scales by mild enzymatic digestion and then allowed to settle on a glass cover slip. In both the dispersed and the aggregated states large numbers of fluorescent fibers are seen. The number and the astral arrangement of these fibers, which run from the central region to the periphery of the cell, are striking. The system of fluorescent fibers is replaced by diffuse fluorescence of moderate intensity after cold treatment, but is restored after rewarming the cells. Differences in the immunofluorescence profiles between cells with dispersed and aggregated pigment are discussed in relation to electron microscopic data available for this system.

Cytoplasmic Granules in Lymphocytes from Rats Dosed with SK&F 14336-D

1971 ◽  
Vol 29 ◽  
pp. 556-557
Author(s):  
T. G. Merrill ◽  
B. J. Payne ◽  
A. J. Tousimis
Keyword(s):  
Lipid Storage ◽  
Pokeweed Mitogen ◽  
Electron Microscopic ◽  
Cytoplasmic Granules ◽  
Storage Diseases ◽  
Tay Sachs Disease ◽  
Large Numbers ◽  
Microscopic Studies ◽  
Neurovisceral Lipidosis

Rats given SK&F 14336-D (9-[3-Dimethylamino propyl]-2-chloroacridane), a tranquilizing drug, developed an increased number of vacuolated lymphocytes as observed by light microscopy. Vacuoles in peripheral blood of rats and humans apparently are rare and are not usually reported in differential counts. Transforming agents such as phytohemagglutinin and pokeweed mitogen induce similar vacuoles in in vitro cultures of lymphocytes. These vacuoles have also been reported in some of the lipid-storage diseases of humans such as amaurotic familial idiocy, familial neurovisceral lipidosis, lipomucopolysaccharidosis and sphingomyelinosis. Electron microscopic studies of Tay-Sachs' disease and of chloroquine treated swine have demonstrated large numbers of “membranous cytoplasmic granules” in the cytoplasm of neurons, in addition to lymphocytes. The present study was undertaken with the purpose of characterizing the membranous inclusions and developing an experimental animal model which may be used for the study of lipid storage diseases.

Morphology and ultrastructure of oral strains of Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus

1980 ◽  
Vol 30 (2) ◽  
pp. 588-600
Author(s):  
S C Holt ◽  
A C Tanner ◽  
S S Socransky
Keyword(s):  
Electron Microscopy ◽  
Ruthenium Red ◽  
Actinobacillus Actinomycetemcomitans ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Large Numbers ◽  
Haemophilus Aphrophilus ◽  
Ruthenium Red Staining ◽  
Amorphous Surface ◽  
Scanning Electron

Selected human oral and nonoral strains of the genera Actinobacillus and Haemophilus were examined by transmission and scanning electron microscopy. The strains examined were morphologically identical to recognized Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus. By transmission electron microscopy, the cells were typically gram negative in morphology, with several strains possessing some extracellular ruthenium red-staining polymeric material. Numerous vesicular structures, morphologically identical to lipopolysaccharide vesicles, were seen to originate from and be continuous with the surface of the outer membrane. Large numbers of these vesicles were also found in the external environment. Scanning electron microscopic observations revealed that both actinobacilli and haemophili possessed surface projections and an amorphous surface material which connected and covered adjacent cells.

Clay particle sizing by electrically-induced birefringence

Clay Minerals ◽  
1982 ◽  
Vol 17 (3) ◽  
pp. 313-325 ◽  
Author(s):  
D. M. Oakley ◽  
B. R. Jennings
Keyword(s):  
Orientational Order ◽  
Decay Rates ◽  
Sufficient Information ◽  
Electron Microscopic ◽  
Experimental Conditions ◽  
Clay Particles ◽  
Electron Microscopic Data ◽  
Rate Of Decay ◽  
Geometry Measurement ◽  
Log Normal

AbstractUnder the influence of a pulsed field, dilute clay sols become birefringent as the particles undergo orientational order. The rate of decay of the birefringence on removal of the field is characteristic of the particle geometry. Measurement of the decay rates under two specific experimental conditions provides sufficient information from which the particle-size distribution can be evaluated in terms of a two-parameter function. Experimental data are reported and analysed in terms of a log-normal distribution of particle sizes for attapulgite (rods), kaolinite (discs) and halloysite (ellipsoids) sols and compared with success to electron microscopic data. The ability of the method to determine size distributions in terms of the major dimensions of the clay particles, rather than those of the often used equivalent sphere, is highlighted.

The Influences of Aqueous Dispersion Media on the Cytotoxic Effect of Zinc Oxide Nanoparticles

2020 ◽  
Vol 19 (05) ◽  
pp. 2050001
Author(s):  
Kim San Tang ◽  
Jey Sern Tan
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Physical Property ◽  
Aqueous Dispersion ◽  
Particle Dispersion ◽  
Oxide Nanoparticles ◽  
Zno Nps ◽  
Electron Microscopic ◽  
Electron Microscopic Data ◽  
Dispersion Media

Zinc oxide nanoparticles (ZnO-NPs) are widely utilized in many applications due to distinct physical and chemical characteristics. There are growing concerns that abundant use of ZnO-NPs can cause harm to humans and the environment. There is a substantial problem with reproducibility in nanotoxicology research due to the inherent properties of nanoparticles. Dispersion media are used for the preparation of nanoparticles. However, the physical and biological behaviors of ZnO-NPs in aqueous dispersion media are poorly understood. In this study, we investigated the effect of ZnO-NPs on the viability of SH-SY5Y cells. Our results showed that ZnO-NPs diluted from water-dispersed stock solution caused significant cell death at a much lower dose compared to their counterpart diluted from the phosphate-buffered saline (PBS)-dispersed stock solution. Electron microscopic data indicated that ZnO-NPs from the PBS-dispersed stock solution form much larger agglomerates compared to the one from the water-dispersed stock solution. From these data, we can conclude that the types of media used for particle dispersion impact the change in the physical property and cytotoxicity of ZnO-NPs.

scholarly journals Mapping of Homologous Interaction Sites in the Hepatitis B Virus Core Protein

1998 ◽  
Vol 72 (6) ◽  
pp. 4997-5005 ◽  
Author(s):  
Sabine König ◽  
Gertrud Beterams ◽  
Michael Nassal
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Main Chain ◽  
Core Protein ◽  
Detectable Effect ◽  
Electron Microscopic ◽  
Protein Variant ◽  
Interaction Sites ◽  
B Virus ◽  
Electron Microscopic Data

ABSTRACT Hepatitis B virus consists of an outer envelope and an inner capsid, or core, that wraps around the small genome plus the viral replication enzyme. The icosahedrally symmetric nucleocapsid is assembled from multiple dimeric subunits of a single 183-residue capsid protein, which must therefore contain interfaces for monomer dimerization and for dimer multimerization. The atomic structure of the protein is not known, but electron microscopy-based image reconstructions suggested a hammerhead shape for the dimer and, very recently, led to a tentative model for the main chain trace. Here we used a combination of interaction screening techniques and functional analyses of core protein variants to define, at the primary sequence level, the regions that mediate capsid assembly. Both the two-hybrid system and the pepscan technique identified a strongly interacting region I between amino acids (aa) 78 and 117 that probably forms part of the dimer interface. Surprisingly, mutations in this region, in the context of a C-terminally truncated but assembly-competent core protein variant, had no detectable effect on assembly. By contrast, mutations in a second region, bordered by aa 113 and 143, markedly influenced capsid stability, strongly suggesting that this region II is the main contributor to dimer multimerization. Based on the electron microscopic data, it must therefore be located at the basal tips of the dimer, experimentally supporting the proposed main chain trace.

A diffusion wake model for tracer ultrastructure-permeability studies in microvessels

1995 ◽  
Vol 269 (6) ◽  
pp. H2124-H2140 ◽  
Author(s):  
B. M. Fu ◽  
F. E. Curry ◽  
S. Weinbaum
Keyword(s):  
Molecular Weight ◽  
Three Dimensional ◽  
Threshold Concentration ◽  
Time Dependent ◽  
Surrounding Tissue ◽  
Low Molecular Weight ◽  
Electron Microscopic ◽  
Small Pore ◽  
Tissue Space ◽  
Transvascular Exchange

We developed a time-dependent diffusion model for analyzing the concentration profiles of low-molecular-weight tracers in the interendothelial clefts of the capillary wall that takes into account the three-dimensional time-dependent filling of the surrounding tissue space. The model provides a connecting link between two methods to investigate transvascular exchange: electron-microscopic experiments to study the time-dependent wake formed by low-molecular-weight tracers (such as lanthanum nitrate) on the tissue side of the junction strand discontinuities in the interendothelial cleft of frog mesentery capillaries (R. H. Adamson and C. C. Michel. J. Physiol. Lond. 466: 303-327, 1993) and confocal-microscopic experiments to measure the spread of low-molecular-weight fluorescent tracers in the tissue space surrounding these microvessels (R. H. Adamson, J. F. Lenz, and F. E. Curry, Microcirculation 1: 251-265, 1994). We show that the interpretation of the presence of tracer as an all-or-none indication of a pathway across the junctional strand is likely to be incorrect for small solutes. Large-pore pathways, in which the local tracer flux densities are high, reach a threshold concentration for detection and are likely to be detected after relatively short perfusion times, whereas distributed small-pore pathways may not be detected until the tissue concentrations surrounding the entire vessel approach threshold concentrations. The analysis using this approach supports the hypothesis advanced by Fu et al. (J. Biomech. Eng. 116: 502-513, 1994) that the principal pathways for water and solutes of < 1.0 nm diameter across the interendothelial cleft may be different and suggests new experiments to test this hypothesis.

scholarly journals Structure of C protein purified from cardiac muscle.

1985 ◽  
Vol 100 (1) ◽  
pp. 208-215 ◽  
Author(s):  
H C Hartzell ◽  
W S Sale
Keyword(s):  
Cardiac Muscle ◽  
Gel Filtration ◽  
Thick Filament ◽  
Protein Molecule ◽  
Striated Muscles ◽  
Electron Microscopic ◽  
C Protein ◽  
Chicken Heart ◽  
Structural Support ◽  
Electron Microscopic Data

C protein is a component of the thick filament of striated muscles. Although the function of C protein remains unknown, a variety of evidence suggests that C protein may regulate actin-myosin interaction or be involved in structural support or elasticity of the sarcomere. We have previously proposed (Hartzell, H. C., 1984, J. Gen. Physiol., 83:563-588) that C protein is involved in regulating twitch relaxation in cardiac muscle. To gain further insight into the function of C protein, we have studied the structure of C protein purified from chicken heart. C protein was purified from extracts of detergent-washed myofibrils by sequential hydroxylapatite and DEAE-Sephacel chromatography. C protein was judged greater than 95% pure by SDS PAGE. The polypeptide subunit had a molecular weight of 155,000 and the native molecule sedimented on linear sucrose or glycerol gradients at 4-5S. For electron microscopy, purified C protein was dialyzed and diluted into a volatile buffer in 50% glycerol, aspirated onto mica, dried under vacuum, and rotary platinum-shadowed. Replicas revealed particles of relatively homogeneous overall dimensions. Over half of the particles were V-shaped. The "arm" lengths of the V-shaped particles were 22 +/- 4.5 nm (SD). Gel filtration on Sephacryl S-300 demonstrated that purified C protein had a Stokes' radius of 5.07 nm. Measurements of viscosity gave an intrinsic viscosity of 16.5 cm3/g. These data are consistent with the electron microscopic data and suggest that C protein in heart muscle is asymmetric. The C protein molecule is large enough to extend from the surface of a thick filament to adjacent thin or thick filaments.

scholarly journals Role of Helicobacter felis in Chronic Canine Gastritis

1992 ◽  
Vol 29 (6) ◽  
pp. 487-494 ◽  
Author(s):  
A. Lee ◽  
S. Krakowka ◽  
J. G. Fox ◽  
G. Otto ◽  
K. A. Eaton ◽  
...  
Keyword(s):  
Gastric Mucosa ◽  
Plasma Cells ◽  
Serum Antibody ◽  
Electron Microscopic Examination ◽  
Gastric Mucus ◽  
Electron Microscopic ◽  
Helicobacter Felis ◽  
Large Numbers ◽  
Histopathologic Changes ◽  
Gastric Parietal Cells

Five gnotobiotic Beagle dogs were orally inoculated with a pure culture of Helicobacter felis. The remaining two littermates served as contact controls. Thirty days after infection, all animals were euthanatized and specimens were collected for evaluation. In infected dogs, H. felis was recovered from all areas of the stomach. Colonization was heaviest in the fundus and antrum. H. felis was not cultured from any segment of the gastrointestinal tract distal to the duodenum. Two weeks after infection, all five infected dogs had detectable IgM and IgG serum antibody to H. felis, whereas control dogs had no measurable H. felis serum antibody throughout the study. Histopathologic changes in the stomachs of infected dogs included large numbers of lymphoid nodules throughout all regions of the gastric mucosa and were most numerous in the fundus and body. A mild, diffuse lymphocytic infiltrate with small numbers of plasma cells and eosinophils was also present in the subglandular region of all portions of the gastric mucosa. Electron microscopic examination revealed large numbers of spiral-shaped H. felis in gastric mucus adjacent to or superimposed over the areas of inflammation. Occasionally, however, H. felis was observed within the canaliculi of gastric parietal cells. Histopathologic changes in the stomachs of the contact control dogs were limited to focal infiltrates of eosinophils and small aggregates of lymphocytes in the subglandular portions of the gastric mucosa in one animal. Infection with H. felis is a likely cause of naturally occurring lymphofollicular gastritis.

Clay mineral mixtures as alteration products in pillow basalts from the eastern flank of Juan de Fuca Ridge: a TEM-AEM study

Clay Minerals ◽  
2001 ◽  
Vol 36 (1) ◽  
pp. 75-91 ◽  
Author(s):  
G. Giorgetti ◽  
P. Marescotti ◽  
R. Cabella ◽  
G. Lucchetti
Keyword(s):  
Electron Microscope ◽  
Juan De Fuca Ridge ◽  
Degree Of Crystallinity ◽  
Electron Microscopic ◽  
Fuca Ridge ◽  
Altered Sample ◽  
Transmission Electron ◽  
Juan De Fuca ◽  
Electron Microscopic Data ◽  
Fe Oxyhydroxides

AbstractTransmission electron microscope-analytical electron microscope analyses have been carried out on secondary minerals from pillow basalts with various degrees of alteration from the Juan de Fuca Ridge (ODP Leg 168). The electron microscopic data indicate that the alteration products consist mainly of phyllosilicate mixtures. The least altered sample shows poorly crystalline phyllosilicates occurrring as flakes with 10 Å -spaced lattice fringes. They have compositions of celadonite mixed with smectite and/or Fe oxyhydroxides and Mg-rich smectite. Proceeding towards older, more altered basalts, the alteration products consist of: (1) poorly crystalline celadonite mixtures and Mg-rich smectite; and (2) phyllosilicates with a higher degree of crystallinity, showing lattice fringes with 9.1 Å -spacing and with a talc-like composition. Changes in phyllosilicate association occur as the type of alteration changes from an oxidizing, water-dominated system (occurrence of celadonite mixtures with Fe hydroxides) to a reducing, rock-dominated system (occurrence of Fe-smectite and talc-like mixtures).

Sign in / Sign up

Export Citation Format

Share Document