View Stock Photo of Smallpox Virus Single Virion As Seen By Negative Stain Electron Microscopy. Find premium, high-resolution photos at Getty Images.
We have developed techniques for studying patch-clamped membranes inside glass pipettes using high voltage electron microscopy (HVEM). To preserve the patch structure with the least possible distortion, we rapidly froze and freeze dried the pipette tip. The pipette is transparent for more than 50 microns from the tip. HVEM images of patches confirm light microscopy observations that the patch is not a bare bilayer, but a membrane-covered bleb of cytoplasm that may include organelles and cytoskeleton. The membrane that spans the pipette is commonly tens of micrometers from the tip of the pipette and occasionally as far as 100 microns. The structure of patches taken from a single cell type is variable but there are consistent differences between patches made from different cell types. With suction applied to the pipette before seal formation, we have seen in the light microscope vesicles swept from the plasmalemma up the pipette. These vesicles are visible in electron micrographs, particularly ...
The structure and distribution of cytoplasmic membranes during mitosis and cytokinesis in maize root tip meristematic cells was investigated by low and high voltage electron microscopy. The electron opacity of the nuclear envelope and endoplasmic reticulum (ER) was enhanced by staining the tissue in …
TY - JOUR. T1 - Solid state amorphization of metastable Al0.5TiZrPdCuNi high entropy alloy investigated by high voltage electron microscopy. AU - Nagase, Takeshi. AU - Takeuchi, Akira. AU - Amiya, Kenji. AU - Egami, Takeshi. PY - 2018/5/1. Y1 - 2018/5/1. N2 - The phase stability of high entropy alloy (HEA), Al0.5TiZrPdCuNi, under fast electron irradiation was studied by in-situ high voltage electron microscopy (HVEM). The initial phase of this alloy quenched from the melt was dependent on cooling rate. At high cooling rates an amorphous phase was obtained, whereas a body-centered cubic (b.c.c.) phase were obtained at low cooling rates. By thermal crystallization of the amorphous phase b.c.c. phase nano-crystals were formed. Upon fast electron irradiation solid state amorphization (SSA) was observed in b.c.c. phase regardless of the initial microstructure (i.e., coarse crystalline structure or nano-crystalline structure with grain boundaries as a sink for point defects). SSA behavior in the ...
TY - JOUR. T1 - Quantitative Electron Microscopic Investigation on Changes of Mitochondria in Long‐Term CPZ Administration in Rat Brain, Liver and Heart. AU - Takeichi, Masashi. AU - Sato, Takeshi. PY - 1987/12. Y1 - 1987/12. N2 - Abstract: The effect of chronic administration of chlorpromazine (CPZ) on mitochondria (MT) in the rat brain (striatum), liver and heart was quantitatively examined with both the electron microscope and computer‐assisted PICTURE ANALYSIS OA‐1. The specimens were taken from six female rats, three controls and three experimentals to which 20 mg/kg body weight of CPZ was administered orally for 15 months from 5 weeks after birth. Thus the quantitative electron microscopic study was made on the mitochondrial sizes (cross‐sectional areas) and cristal densities and the following results were obtained: 1) The sizes of MT from the striatal nerve cells and axo‐dendritic spine postsynapses and liver parenchymal cells were larger in the CPZ‐administered rats than in ...
1963 Conference on Electron Microscopy, Gliwice, chairman: S. Gorczyca, in Polish, 10 papers (unpublished) 1971 II Polish Conference on Electron
Electron microscopic localization of acetylcholinesterase in the superior cervical ganglion of the rat. In: Kolligátum. pp. 274-285. (1967 ...
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TY - JOUR. T1 - A structural study of tin-antimony oxide catalysts by high-resolution electron microscopy. AU - Berry, Frank J.. AU - Smith, David J.. PY - 1984/7. Y1 - 1984/7. N2 - Tin-antimony oxide catalysts prepared by the calcination of precipitates have been investigated by high-resolution electron microscopy. The exposure of the catalysts prepared at low temperatures to gaseous atmospheres containing hydrocabon and oxygen results in a segregation of antimony from the poorly crystalline rutile-type solids and the development of an amorphous material. The catalysts containing low concentrations of antimony are also partially converted to a non-rutile-type crystalline phase. Prolonged calcination in air of the used catalysts at high temperatures leads to the attainment of bulk equilibrium and the formation of solid solutions of antimony in tin(IV) oxide. Treatment of the equilibrated crystalline catalysts prepared at high temperatures in the hydrocarbon and oxygen gas stream gives rise to ...
A method for forming a zoned distribution of particulate material within a fibrous web includes a conveying step for providing a gas entrained supply of the particulate material and a segregating step centrifugally directing at least a portion of the particulate material into an accumulation region. A transferring step selectively directs particulate material from the accumulation region into a delivery gas stream to provide an intermittent flow volume of a selected quantity of particulate material from the accumulation region through a delivery conduit and into a web forming chamber. A fiberizing step provides a flow of a selected fibrous material into the web forming chamber, and a directing step controls the intermittent flow of particulate material from the delivery conduit into the forming chamber. A foraminous forming layer is disposed within the forming chamber for receiving the fibrous material and the particulate material to produce a fibrous web which includes zoned regions having selected,
Mitosis in yeast Saccharomyces cerevisiae was investigated in thick (0-25-I mum) serial sections with a high voltage electron microscope and in preparations of spheroplasts spread on a water surface. Spindle microtubules originate from a plaque-like structure called the spindle pole bosis the SPB duplicates and a set of long and short microtubules develops on each SPB. The spindle arises as the SPBs separate on the nuclear membrane adense and are not individually visible. Genetic studies, however, have indicated that there are 17 linkage groups. The number of microtubules was determined in diploid and haploid spindles on serial stereo micrographs. In diploid mitosis about 40 microtubules issue from a SPB. Most are non-continuous and often they are visibly associated with a chromatin fibre. The spindle in haploid cells is similar except that the number of microtubules is about half that in diploid cells and the SPB is smaller. The pole-to-pole microtubules vary in number from spindle to spindle, ...
TY - JOUR. T1 - The structure of grain boundaries in granite-origin ultramylonite studied by high-resolution electron microscopy. AU - Hiraga, T.. AU - Nagase, Toshiro. AU - Akizuki, M.. PY - 1999/9/1. Y1 - 1999/9/1. N2 - The structure of grain boundaries in a granite-origin ultramylonite, composed mainly of fine-grained feldspar and quartz, was studied by high-resolution electron microscopy (HREM). At most of the boundaries, not only between the same minerals but also between different minerals, lattice fringes in adjacent grains meet at the interface with no other appreciable phases. In these boundaries, some of the straight segments correspond to a low-index plane of one of the connected grains. Boundaries containing voids, with a spheroidal shape elongated along the boundaries, were observed only between quartz grains. It is suggested that these boundaries were formed by healing of microcracks. The structural width of major boundaries, deduced from lattice-fringe imaging, is less than about ...
The Acanthamoeba castellanii myosin-Is were the first unconventional myosins to be discovered, and the myosin-I class has since been found to be one of the more diverse and abundant classes of the myosin superfamily. We used two-dimensional (2D) crystallization on phospholipid monolayers and negative stain electron microscopy to calculate a projection map of a classical myosin-I, Acanthamoeba myosin-IB (MIB), at ∼18 Å resolution. Interpretation of the projection map suggests that the MIB molecules sit upright on the membrane. We also used cryoelectron microscopy and helical image analysis to determine the three-dimensional structure of actin filaments decorated with unphosphorylated (inactive) MIB. The catalytic domain is similar to that of other myosins, whereas the large carboxy-terminal tail domain differs greatly from brush border myosin-I (BBM-I), another member of the myosin-I class. These differences may be relevant to the distinct cellular functions of these two types of myosin-I. ...
Biology is a challenging and complicated mess. Understanding this challenging complexity is the realm of the biological sciences: Trying to make sense of the massive, messy data in terms of discovering patterns and revealing its underlying general rules. Among the most powerful mathematical tools for organizing and helping to structure complex, heterogeneous and noisy data are the tools provided by multivariate statistical analysis (MSA) approaches. These eigenvector/eigenvalue data-compression approaches were first introduced to electron microscopy (EM) in 1980 to help sort out different views of macromolecules in a micrograph. After 35 years of continuous use and developments, new MSA applications are still being proposed regularly. The speed of computing has increased dramatically in the decades since their first use in electron microscopy. However, we have also seen a possibly even more rapid increase in the size and complexity of the EM data sets to be studied. MSA computations had thus become a
A hemagglutination-inhibitory mucoprotein from human urine has been studied with the electron microscope. It consists of filaments, with diameters of 40 to , 240 A, composed of smaller fibrils. In the two-dimensional projection of the electron micrographs, the single fibrils often show a zig-zag course with a periodicity of 100 to 140 A; the single branch of a zig-zag measures about 60 A in length and either 20 or 40 A in width. Still thinner fibrillar elements are observable with diameters of 10 A or less. In three-dimensional aspect, the zig-zag structure might be a helix. The fibril-bundle (or filament) reveals a complicated configuration. Heat treatment at 70°C shows some indication of denaturation (e.g. filaments are shorter), whereas at 80°C almost complete degradation of the protein into individual zig-zag elements or smaller pieces is attained. The interaction between influenza virus particles and inhibitory mucoprotein consists of the attachment of a fiber molecule to the virus ...
EMDB EMD-22958: Negative stain electron microscopy reconstruction of 2P SARS-CoV-2 spike ectodomain in complex with Fabs DH1047 and DH1051
Microplastics collected at sea harbour a high diversity of microorganisms including some Vibrio genus members, raising questions about the role of microplastics as a novel ecological niche for...
Fibrinogen conjugated to colloidal gold or colloidal gold-monoclonal anti-glycoprotein IIb/IIIa (fibrinogen receptor) was used to label the receptor on platelets. Whole mount preparations were examined by stereo pair high voltage electron microscopy and then by scanning electron microscopy to determine the feasibility of this approach in detecting the number of receptors and their location relative to the cytoskeletal and surface structure. Both the ligand-gold and antibody-gold labels were effective. The relative numbers of receptors could be seen and their relationship to cytoskeletal structure could be determined. Marked differences in receptor number and distribution were observed when platelets in different stages of activation were compared. In co-cultured macrophages and platelets, receptors were found exclusively on platelets or on pieces of platelet membrane adherent to macrophages.
The fusion of lysosomes to phagosomes was observed under high voltage electron microscopy, in 4μm thick rat retinal sections with the aid of acid phosphatase cytochemistry. The study of thick sections facilitates the observation of the moment of fusion in stereo view from two tilted pictures. From this study, the contents of the lysosome pored into the phagosome through the orifice, shortly after the collision of the two organelles. The hydrolytic enzymes such as acid phosphatase spread in a sheet under the limiting membrane of the phagosome to finally form a balloon of the reaction product. In some case the ballooning appeared to be doubled. The outer skin of the reaction product may be the result of a wrapping mechanism of phagolysosomes.. ...
Time-lapse images of particulate matter (PM) deposition on diesel particulate filters (DPFs) at the PM-particle scale were obtained via field-emission scanning electron microscopy (FE-SEM). This particle scale time-series visualization showed the detailed processes of PM accumulation inside the DPF. First, PM introduced into a micro-pore of the DPF wall was deposited onto the surface of SiC grains composing the DPF, where it formed dendritic structures. The dendrite structures were locally grown at the contracted flow area between the SiC grains by accumulation of PM, ultimately constructing a bridge and closing the porous channel. To investigate the dominant parameters governing bridge formation, the filtration efficiency by Brownian diffusion and by interception obtained using theoretical filtration efficiency analysis of a spherical collector model were compared with the visualization results. The initial deposition of PM on the SiC grains showed good agreement with theoretical observations, ...
TY - JOUR. T1 - Anatomical and physiological observations on synapses formed on isolated autonomic neurons in tissue culture. AU - Bunge, Richard P.. AU - Rees, Rosemary. AU - Wood, Patrick. AU - Burton, Harold. AU - Ko, Chien Ping. N1 - Funding Information: We benefited from the opportunity to discuss the development of this system with Drs. Dennis Bray, Stanley Crain and Robert Porter. Supported by NIH Grants NS-09923 and NS-09809 and GRS-5 SO1 RR05398.. PY - 1974/2/8. Y1 - 1974/2/8. N2 - Neurons from the superior cervical ganglion of perinatal rats were freed of their supporting cells and established in culture by the method of Bray. To these were added meninges-free explants of embryonic rat thoracic spinal cord to allow interaction between the outgrowing cord neurites and the isolated autonomic neurons. Electron microscopic observations on the autonomic neurons in these preparations revealed the presence of axon terminals of two types. One type (presumably adrenergic) contained pleomorphic ...
Even small amounts of amorphous materials can have a significant effect on the drug product. Are gravimetric vapour sorption techniques an effective solution to characterize amorphous materials?
Methodology to annotate the multiple origins of axonal projections in dense electron microscopy data of mammalian nervous tissue without the need of chemical label conversion is reported.
A light-and electron-microscopic study of pig hepatocytes from late prenatal to early neonatal animals shows changes which reflect an increasing rate of synthetic activity. The granular endoplasmic reticulum (ER) in the prenatal pig hepatocyte is situated along the periphery of the cytoplasm and in the region immediately surrounding the nucleus. Mitochondria are most abundant in the area adjacent to the nucleus, while the Golgi complex is generally located in the region of the bile canaliculus. The remaining portion of the hepatocyte is occupied with glycogen. A few hours after birth the hepatocyte increases about twofold in size with the nucleus shifting from a peripheral to a more centrally located position. The glycogen decreases quickly coincident with a rapid increase in the amount of granular ER and the dispersion of the mitochondria throughout the cell. The Golgi complex becomes distended and numerous vesicles appear in its immediate vicinity containing a moderately dense material. ...
Out of 54 open renal biopsies performed on children, 17 were selected and studied not only by light microscopy but also by electron microscopy. Statistical-mathematical analysis of basement membrane thickness-measurements was carried out. It is concluded that electron microscopic investigation of the renal biopsy material is required in selected cases involving diagnostic or therapeutic problems. In nephrotic syndrome it may help above all to separate minimal changes from early forms or glomerular lesion of the focal sclerosing type. Electron microscopy can also be useful in any of the mono- and oligosymptomatic renal diseases. In those cases only electron microscopy makes it possible to provide exact morphological diagnosis which is necessary to the proper therapy. ...
Partial denaturation pattern of sex factor deoxyribonucleic acid of Escherichia coli was studied by electron microscopy. Clustering of the adenine-plusthymine-rich regions in one part of the molecule was revealed. The positions of these regions were located on the physical map of F by analyzing the partial denaturation pattern of heteroduplexes between F and F-prime factors with various parts of F sequences deleted. ...
TY - CHAP. T1 - Correlative light and electron microscopy of autophagosomes. AU - Gudmundsson, Sigurdur Runar. AU - Kahlhofer, Jenny. AU - Baylac, Nastassia. AU - Kallio, Katri Anneli. AU - Eskelinen, Eeva-Liisa. PY - 2019/1. Y1 - 2019/1. N2 - Live-cell imaging has been widely used to study autophagosome biogenesis and maturation. When combined with correlative electron microscopy, this approach can be extended to reveal ultrastructural details in three dimensions. The resolution of electron microscopy is needed when membrane contact sites and tubular connections between organelles are studied.. AB - Live-cell imaging has been widely used to study autophagosome biogenesis and maturation. When combined with correlative electron microscopy, this approach can be extended to reveal ultrastructural details in three dimensions. The resolution of electron microscopy is needed when membrane contact sites and tubular connections between organelles are studied.. KW - 1182 Biochemistry, cell and molecular ...
Hi, I am Stefan Fischer. I am biologist at the University of Tübingen, working in the department for Evolutionary Biology of Invertebrates (Institute of Evolution and Ecology). My methodological focus is set on electron microscopy. Furthermore I do focus on 3D techniques, be it on basis of semi-thin sections (LM), Ultra-thin sections (ssTEM) and also MicroCT data. For that reason I developed a strong interest in open source software packages and image analysis in order to automate (or semi-automate) some of the tedious parts of my workflows.. ...
Conventional electron microscopy offers a substantial resolution advantage over light microscopy, but requires difficult and often destructive preparation techniques. Recent advances in electron microscopy allow for imaging of hydrated samples, retaining the resolution advantage while removing the difficulty in preparation. Two new techniques, environmental scanning electron microscopy and wet electron microscopy offer this advantage, allowing for new possibilities in biological imaging.
The fine structure of the His bundle is described on the basis of its light and electron microscopic appearance. Electron microscopy was performed on one human and two canine hearts, and light microscopy on over 400 human and 60 canine hearts. The His bundle was identified by its light microscopic appearance. There were no significant differences in the fine structure of human and canine His bundles. In both, the principal cell was a typical Purkinje cell containing few myofibrils and a large perinuclear clear zone; these cells are shorter and broader than working myocardial cells, and their intercellular junctions (which are obliquely rather than transversely oriented) contain a high proportion of nexus formations. Both the human and canine His bundles are partitioned by fine collagen septa, which are longitudinally oriented with comparatively few crossover connections. The general organization of the His bundle is thus into multiple strands of Purkinje cells, and these strands are largely ...
With the use of the method described in the preceding paper (to be referred to subsequently as I) for constructing the displacement fields, the electron microscope image contrast of small dislocation loops and of stacking-fault tetrahedra has been computed from numerical solutions of the Howie-Whelan (1961) equations. The computer-simulated images, displayed in the form of half-tone pictures, have been used to identify the nature and geometry of such defects in ion-irradiated foils. A systematic study of the contrast of small Frank loops in Cu+ ion irradiated copper under a wide variety of diffraction conditions is reported. In particular the variations of the contrast of loops edge-on and inclined to the electron beam with the operating Bragg reflexion, the thickness and inclination of the foil, depth of the defect in the foil and deviation from the Bragg-reflecting condition have been studied. Methods of obtaining useful information, such as the diameters of the loops, are suggested. The ...
A new type of Sr-containing sialon polytypoid phase with the structural formula SrSi10-xAl18+xN32-xOx (x approximate to l) has been found in the Sr-Si-Al-O-N system. The phase was characterised by X-ray powder diffraction (XRPD), and its structure was investigated by electron diffraction (ED) and high resolution electron microscopy (HREM). It is considerably disordered, but the average structure has a rhombohedral unit cell with a=5.335(5)approximate to root 3.a(AIN) and c= 79.1(1)Angstrom approximate to 30.c(AIN). The Sr atoms ave located in layers M-Sr-M, M=(Si/Al), at the origin of the unit cell with 12 X= (O,N) atoms around it, at distances of similar to 3 Angstrom, forming a cubo-octahedron. The X atoms that form a hexagon around the Sr atom in the ab plane are corner shared by M = (Si/Al) tetrahedra with opposite polarity in adjacent layers in which 2/3 of the tetrahedra are occupied. The M-Sr-M layers alternate with normally eight-layer-thick AIN type blocks, although the thickness of ...
The antimalarial drug, artemisinin packs a double whammy -- exploding inside malaria parasites and shutting down the waste disposal system that deals with the damage. Resistance to artemisinin, can be overcome by co-treating parasites with an anti-cancer drug of the proteasome-inhibitor class. Electron microscope images of malaria parasites (blue) generated by Associate Professor Eric Hanssen, University of Melbourne, Australia, and chemical structure of artemisinin.
SMITH, DJ and FREEMAN, LA and MCMAHON, RA and AHMED, H and PITT, MG and PETERS, TB (1984) CHARACTERIZATION OF SI-IMPLANTED AND ELECTRON-BEAM-ANNEALED SILICON-ON-SAPPHIRE USING HIGH-RESOLUTION ELECTRON-MICROSCOPY. J APPL PHYS, 56. pp. 2207-2212. ISSN 0021-8979. Full text not available from this repository ...
RICHMOND, Va., June 7 /PRNewswire-USNewswire/ -- National Environmental Testing Lab Now IDs Carbon Black with Electron-Microscopy.
Learn how your ultrastructural investigations can benefit from modern electron microscope techniques. Correlative microscopy provides you deeper insights about cell structure by combination of light and scanning electron microscopy methods.
TY - JOUR. T1 - The mechanism of vortex connection at a free surface. AU - Zhang, Chiong. AU - Shen, Lian. AU - Yue, Dick K.P.. PY - 1999/4/10. Y1 - 1999/4/10. N2 - Vortex connections al the surface are fundamental and proouncnc features to free-surface vortical flows. To understand the detailed mechanism of such connection, we consider, as a canonical problem, the laminar vortex connections at a free surface when an oblique vortex ring impinges upon thai surface. We perform numerical simulations of the Navier Stokes equations with viscous free-surface boundary conditions. It is found that the key to understanding the mechanism of vortex connection at a free surface is the surface layers: a viscous layer resulting from the dynamic zero-stress boundary conditions at the free surface, and a thicker blockage layer which is due to the kinematic boundary condition at the surface. In the blockage layer, the vertical vorticity component increases due to vortex stretching and vortex turning (from the ...
Cryoelectron microscopy of biological molecules is among the hottest growth areas in biophysics & structural biology at present.Frank, Joachim is the author of Three-Dimensional Electron Microscopy Of Macromolecular Assemblies Visualization Of Biological Molecules In Their Native State, published 2006 under ISBN 9780195182187 and ISBN 0195182189. [read more] ...
TY - JOUR. T1 - Oxidation of bismuth-tungsten bronzes. AU - Jefferson, D. A.. AU - Uppal, M. K.. AU - Smith, David J.. PY - 1984/6. Y1 - 1984/6. N2 - The oxidation of bismuth-tungsten bronzes at 600 and 950°C has been studied using high-resolution electron microscopy at 200 and 500 kV. At the lower temperature, a topotactic transformation to lamellae of Bi2WO6 in a WO3 matrix was observed but at higher temperature larger crystals were produced, primarily of Bi2W2O9 but with some disordered intergrowths.. AB - The oxidation of bismuth-tungsten bronzes at 600 and 950°C has been studied using high-resolution electron microscopy at 200 and 500 kV. At the lower temperature, a topotactic transformation to lamellae of Bi2WO6 in a WO3 matrix was observed but at higher temperature larger crystals were produced, primarily of Bi2W2O9 but with some disordered intergrowths.. UR - http://www.scopus.com/inward/record.url?scp=0021442349&partnerID=8YFLogxK. UR - ...
Results The LVP consists of a broad nucleocapsid surrounding an electron-dense centre, presumably containing the HCV genome. The nucleocapsid is surrounded by an irregular, detergent-sensitive crescent probably composed of lipids. Lipid content may determine particle size. These particles carry HCV E1E2, ApoB and ApoE, as shown in our immuno-EM analysis. Our results also suggest that these putative LVPs circulate in the serum of patients as part of a mixed population, including lipoprotein-like particles and complete viral particles. ...
Results The LVP consists of a broad nucleocapsid surrounding an electron-dense centre, presumably containing the HCV genome. The nucleocapsid is surrounded by an irregular, detergent-sensitive crescent probably composed of lipids. Lipid content may determine particle size. These particles carry HCV E1E2, ApoB and ApoE, as shown in our immuno-EM analysis. Our results also suggest that these putative LVPs circulate in the serum of patients as part of a mixed population, including lipoprotein-like particles and complete viral particles. ...
With the resolution becoming sufficient to reveal individual atoms, HREM is now entering the stage where it can compete with X-ray methods to quantitatively determine atomic structures of materials without much prior knowledge, but with the advantage of being applicable to aperiodic objects such as crystal defects. In our view the future electron microscope will be characterised by a large versatility in experimental settings under computer control such as the illumination conditions (TEM-STEM), CBED, detecting conditions (diffraction, image, ptychography) and many other tunable parameters such as focus (g), voltage, spherical aberration (C-s), beam tilt, etc. Since modem detectors can detect single electrons, also the counting statistics is known. The only limiting factor in the experiment will be the total number of electrons that interact with the object during the experiment due to the limitations in the exposure time or in the object damage. However, instrumental potentialities will never ...
Transmission electron micrographs showing the tracheal epithelium in Ig-deficient mice. The tracheal epithelium in SAL/SAL-treated animals (a) harbored only
An electron microscopic investigation was performed on 28 Clostridium difficile strains isolated from 15 antibiotic-associated diarrhea cases and from 13 healthy infants. Through the use of supernatants of the cultures induced by mitomycin C (1 or 3 micrograms/ml), 18 of the 28 C. difficile strains …
Free Public Domain Picture: Here a negative stain electron micrograph reveals a M (mulberry type) monkeypox virus virion in human vesicular fluid. See PHIL 10817 for | ID: 13540024213919
Schulte, E., 1972: Electron microscopic studies on renal tubules (Malpighian tubules) in Drosophila melanogaster. V. Localization of Na-adenosine triphosphatase
The THO complex participates during eukaryotic mRNA biogenesis in coupling transcription to formation and nuclear export of translation-competent messenger ribonucleoprotein particles. In Saccharomyces cerevisiae, THO has been defined as a heteropentamer composed of the Tho2p, Hpr1p, Tex1p, Mft1p, and Thp2p subunits and the overall three-dimensional shape of the complex has been established by negative stain electron microscopy. Here, we use small-angle X-ray scattering measured for isolated THO components (Mft1p and Thp2p) as well as THO subcomplexes (Mft1p-Thp2p and Mft1p-Thp2p-Tho2p) to construct structural building blocks that allow positioning of each subunit within the complex. To accomplish this, the individual envelopes determined for Mft1p and Thp2p are first fitted inside those of the Mft1p-Thp2p and Mft1p-Thp2p-Tho2p complexes. Next, the ternary complex structure is placed in the context of the five-component electron microscopy structure. Our model reveals not only the position of ...
TY - JOUR. T1 - Efficient three-dimensional reconstruction of synapse with high-voltage electron microscopy. AU - Kea, Joo Lee. AU - Park, Chang Hyun. AU - Rhyu, Im Joo. N1 - Funding Information: The authors would like to thank Dr Kiyoshi Hama for helpful comments on the manuscript. We appreciate the strong support of the HVEM group at KBSI, Dae-Jeon, South Korea. This work was supported by Brain Korea 21 Project for Biomedical Science and grant from the Korean Health 21 R&D Project, Korean Ministry of Health and Welfare (HMP-00-GN-01-0002).. PY - 2005/4. Y1 - 2005/4. N2 - Three-dimensional (3-D) information on nervous tissue is essential for the understanding of brain function. Especially, 3-D synaptic analyses on serial ultrathin sections with transmission electron microscopy (TEM) have contributed to the knowledge on neural plasticity associated with various pathophysiological conditions. The 3-D reconstruction procedures, however, not only require a great amount of expertise but also include ...
Electron microscopic observations on normally differentiating and α-MSH (melanocytestimulating hormone)-treated epidermal melanocytes of newborn mouse skin were carried out. The process of melanocyte differentiation from premelanosome-containing melanoblasts was investigated in detail with respect to melanosomes as markers.. Melanoblasts containing unmelanized premelanosomes gradually decreased in number after birth, while the number of melanocytes rapidly increased. The epidermis of α-MSH-treated 3-day-old mice and normal 6-day-old mice contained melanocytes with numerous fully melanized melanosomes, and with no or only a few melanoblasts.. Changes in other organelles in differentiating melanocytes were also noticeable. Golgi apparatus and RER (rough endoplasmic reticulum) decreased in number during the normal or α-MSH-induced differentiation of the epidermal melanocytes, though the number of mitochondria showed no notable change. The number of SER (smooth endoplasmic reticulum) per cell did ...
The effect of 0.5 mM cadmium (Cd) was studied on the ultrastructural aspects and pectin features of the walls of flax cellulosic fibres when the thickening of secondary wall had just started in the hypocotyl of 10-day old seedlings. As seen by PATAg staining in controls, cell-wall formation displayed two distinct steps, secretion and remodelling, which did not occur simultaneously for all the neighbouring fibres. The inner part of the secondary wall, where the cellulose molecules had just been synthesized, appeared very reactive to PATAg. The outer part, where the cellulose fibrils associated in larger microfibril complexes, became non-reactive to PATAg. Under Cd treatment, we noticed some acceleration of fibre differentiation in terms of fibre number, wall thickness and yield. As revealed by PATAg staining, treated fibres exhibited a disturbed cell-wall texture, indicating a modified adhesion between the matrix polysaccharides and the cellulose microfibrils. The Cd impact on the distribution of highly
The non-clay and clay mineralogy of the British argillaceous sedimentary rocks are discussed. The non-clay mineralogy is only considered in general terms due to the lack of detailed information. The general nature of the clay minerals, their genesis and the effects of burial diagenesis on clay minerals are reviewed. This is followed by a more detailed examination of the clay mineralogy of the Palaeozoic, Mesozoic and Tertiary argillaceous rocks. Consideration is given to the relative importance of the depositional environment and burial diagenesis in forming the clay assemblages now found in British mudrocks.. The petrology of the argillaceous sedimentary rocks is discussed in general terms. The use of electron microscopy in the examination of mudrocks generally and some British examples in particular is reviewed, including a discussion of the nature and origin of fissility. The possibility of using high voltage electron microscopy in future studies of argillaceous sediments is proposed based on ...
Human lenses extracted for cataract 26 years after long-term exposure to an imperfectly shielded radium source were examined by slit-lamp photography, thin-section light microscopy, and electron microscopy. Anterior epithelial cells were fibroblast-like, and germinal epithelium and vacuolated cortical fibres had accumulated at the equator. A zone of light scatter at the anterior pole corresponded to an area of breakdown of cortical lens fibres, where unusual feathery fibres were orientated perpendicular to the lens surface. Two zones of light scatter separated by a 250-microM clear interval were seen in the posterior cortex. The zone at the posterior pole corresponded to an area of fibre liquefaction and large rounded membrane whorls, while the deeper zone comprised small flattened membrane whorls. The characteristic plaques of swollen abnormal cells described in previous histological studies of x-ray cataract were not present. This and other differences probably reflect the extremely long time ...
1. 1. At the growth temperature the total phospholipids isolated from Escherichia coli cells give rise to 31P-NMR spectra which indicate the existence of lamellar, isotropic and hexagonal phases. These phases are also detected by freeze-fracture electron microscopy. In particular, the isotropic phase may contain lipidic particles (possibly inverted micelles) ... read more associated with the lamellar phase. 2. 2. The cytoplasmic membrane isolated from E. coli cells grown at 37°C is mainly lamellar at 25°C, whereas at 37 and 45°C the presence of some almost isotropic phospholipid motion is indicated. The possible significance of the isotropic phase for the functioning of the cytoplasmic membrane is discussed. show less ...
The adult lobster Homarus gammarus is a weak hyper-regulator at low salinity. The objective of this study was to locate the ion-transporting tissues in the branchial chamber of this species, using electron microscopy and confocal laser scanning microscopy with a fluorescent vital stain for mitochondria, DASPMI, which is widely used to locate mitochondria-rich cells in ion-transporting epithelia of fish. A thick mitochondria-rich epithelium is present on the inner side of the branchiostegite and over the entire surface of the epipodites. Ultrastructural observations confirm that this tissue has features typical of an ion-transporting epithelium. When the lobster is transferred to low salinity, these epithelia undergo marked ultrastructural changes, such as an increase in thickness related to the development of basolateral infoldings, the appearance of numerous vesicles and an increase in height of the apical microvilli. In the gills, the branchial filaments are lined by a thin and poorly ...
EVP is an associate professor of computer systems department in School of Natural Sciences in Far Eastern Federal University. He has a Ph.D. in Physics and great experience in electron microscopy. His scientific interests are electron microscopy, physics of condensed matter, image processing, and high-performance computations on GPU. EBM is currently a Ph.D. student of School of Natural Sciences in Far Eastern Federal University. His Ph.D. project focuses on electron microscopy of amorphous and nanocrystalline metallic alloys and their structure changes under external impact. OVV is a Ph.D. student of School of Natural Sciences in Far Eastern Federal University. His Ph.D. project focuses on electron microscopy and electron tomography of structure inhomogeneities in amorphous metallic alloys.ANF holds a BS degree in Information Systems from Far Eastern Federal University. He is currently working toward a masters degree in Information Systems and Technologies at Far Eastern Federal University. He ...
Due to its actin-sequestering properties, thymosin beta-4 (Tβ4) is considered to play a significant role in the cellular metabolism. Several physiological properties of Tβ4 have been reported;, however, many questions concerning its cellular function remain to be ascertained. To better understand the role of this small peptide we have analyzed by means of transmission immunoelectron microscopy techniques the ultrastructural localization of Tβ4 in HepG2 cells. Samples of HepG2 cells were fixed in a mixture of 3% formaldehyde and 0.1% glutaraldehyde in 0.1 M cacodylate buffer and processed for standard electron microscopic techniques. The samples were dehydrated in a cold graded methanol series and embedded in LR gold resin. Ultrathin sections were labeled with rabbit antibodies to Tβ4, followed by gold-labeled goat anti-rabbit, stained with uranyl acetate and bismuth subnitrate, observed and photographed in a JEOL 100S transmission electron microscope. High-resolution electron microscopy ...
After monolayer cultures of rat islets were exposed to [125I]insulin,[125I]glucagon, and [125I]tyrosinyl somatostatin, specific autoradiographic grains associated with each radioactively labeled ligand were found on B, A, and D cells.The density of labeling of the B, A, and D cells with each labeled ligand correlated well with the known actions of the three hormones on each of the islet cells. ...
Ice crystal larger than about 5 μm diameter were separated from interstitial particles in aircraft contrails and evaporated. Residual particles larger than 0.1 μm were analyzed by electron microscopy. Soot, metals, and volatile organic substances, apparently from the aircraft exhaust, were found. However, the residual particles also contained high percentages of minerals, thought to be crustal in origin, that were often mixed with sulfur. The percentages of particles in our samples (representing the larger residual particles from relatively large ice crystals) identified as exhaust-derived and the percentage apparently derived from the ambient aerosol were roughly equal, suggesting that ambient particles may be important in contrail formation. Possible explanations for this are presented ...
The presently acknowledged onset of synaptogenesis in the chick retina from embryonic day 12 (E12) onward stands in contrast with the appearance of spontaneous electrical activity, of presynaptic proteins, or of neurotransmitters during early formation of the inner (E6-E8) and outer (E9) plexiform layers. Therefore, we investigated the chick retina from E6 to E12 at which age first synapses appear by transmission electron microscopy (TEM). The study provides evidence that synaptogenesis in the chick retina begins shortly after the plexiform layers have started to emerge. The first synapses are electrical synapses, which appear on E7, one day after the future inner plexiform layer emerged, and towards the end of E8 in the nascent outer plexiform layer. Conventional chemical synapses appear in both plexiform layers on E8, in the inner plexiform layer (stage 34) only a few hours earlier than in the outer plexiform layer (stage 35). The first synapses are formed close to the apex of the optic fissure and
We report the nanostructure study results, mainly based on plan-view transmission electron microscopy (TEM) on the coalescence process during the overgrowth by metalorganic chemical vapor deposition of GaN nanocolumns grown by molecular beam epitaxy. In cross-section scanning electron microscopy images, one can observe a two-stage coalescence overgrowth process. First, a group of nearby nanocolumns is merged into a thicker column. One of the possible merging processes is the growth of a bridging domain between two columns for their connection. The thicker columns are then developed into horn-shaped structures for the second-stage coalescence. Because different columns may have different crystal orientations, stacking faults can be formed for implementing the coalescence between two domains. Such stacking faults around the boundaries of merged domains represent one of the major kinds of defect after the threading dislocation density is reduced based on the nanocolumn growth technique.. ©2013 ...
In 1981 Taxy et al described first two cases of epithelioid schwannoma. The clinical, gross, and light microscopic features of two epithelioid tumours were not typical of either benign or malignant schwannoma. Electron microscopic features were indicative of benign Schwann cell tumours.. In 1985 Frank et al described electron microscopic features of Schwann cells in epithelioid schwannoma.. It was first reported as cutaneous epithelioid schwannoma by Kindblom et al in 1998.. The tumors are predominantly dermal/subcutaneous in location and involve the lower limb, upper limb, trunk and head/neck. These tumors may cause diagnostic errors due to their increased cellularity and epithelioid morphology. Typical histologic features of classic schwannoma such as Antoni A and B areas, Verocay bodies, and hyalinized vessels are either absent or only present in focal areas. Strong and diffuse S-100 protein expression is seen in both benign and malignant counterparts of epithelioid schwannoma. Type IV ...
TY - JOUR. T1 - An iterative method for obtaining a nonlinear solution for the temperature distribution of a rotating spherical body revolving in an eccentric orbit. AU - Sekiya, Minoru. AU - Shimoda, A. A.. PY - 2014/1/1. Y1 - 2014/1/1. N2 - An iterative method for determining the temperature distribution in a rotating spherical body with an eccentric orbit around a star is developed. The heating term is expanded into the Fourier series with respect to the mean anomaly and the spherical harmonics with respect to the longitude and colatitude of a spherical body. The obtained formula is suitable for the eccentricity less than about 0.7. The remaining procedure to determine the temperature using an iterative method is the same as that described in Sekiya and Shimoda (2013). The method for determining the change rates of orbital elements due to the Yarkovsky effect is also developed. Our method is applicable to any value of the rotation period of a body. The errors of our results are less than 1%. ...
Guinea pigs approximately 8 months old, maintained on a diet of rabbit pellets and carrots, developed abnormalities similar to some of those described for scorbutic guinea pigs (Follis, 1963). Approximately half of the animals developed a fibrovascular proliferation in the thigh muscles which caused up to sixfold increase in the normal volume of the thigh (Meheregon, personal communication). Tissue from the swollen legs grew in culture in Eagle's medium as a confluent, fibroblast-like sheet, whereas normal-sized leg muscles of the same animals did not grow under the same conditions. Increase in cell number occurred for 4 to 6 weeks and then the culture became stationary. This report presents electron microscopic evidence for the presence of virus-like particles, possible developmental forms of a pox virus, in the cells in culture. Cultures were obtained by treatment of the tissues with 0.25% trypsin for 15 min.; the dispersed cells were collected by centrifugation, suspended in tissue culture
Hepatitis A pathogen (HAV) infects African green monkey kidney cells via HAV cellular receptor 1 (havcr-1). to the Fc and hinge portions of human IgG1. D1muc-Fc neutralized 10 occasions more HAV than did D1-Fc. Sedimentation evaluation in sucrose gradients demonstrated that treatment of HAV with 20 to 200 nM D1muc-Fc disrupted a lot of the virions, whereas treatment with 2 nM D1muc-Fc acquired no influence on the sedimentation from the contaminants. Treatment of HAV TAK-875 with 100 nM D1muc-Fc led to low-level deposition of 100- to 125S contaminants. Negative-stain electron microscopy evaluation revealed the fact that 100- to 125S contaminants acquired the features of disrupted virions, such as for example inner staining and diffuse sides. Quantitative PCR evaluation showed the fact that 100- to 125S contaminants included viral RNA. These outcomes indicate that D1 as well as the mucin-like area of havcr-1 must induce conformational adjustments resulting in HAV uncoating. Hepatitis A pathogen ...
The present study was designed to develop a technique to prepare human chromosomes for sequential light and electron microscopic observation and to compare detectability of chromosome aberrations induced by adriamycin and mitomycin C by the two procedures. The technique developed preserved the morphological and structural organization of chromosome while allowing observation of the cells entire chromosome complement. It was rapid and reproducible and chromosomes could be treated and stained for banding. Light microscopic data showed that in cultures of human lymphocytes both drugs induce chromosome aberrations. In comparison with controls both drugs produced significantly more chromosome and chromatid fragments. Electron microscopy revealed greater numbers of chromosome aberrations in both drug groups at higher levels of statistical significance. The differences between chromosome and chromatid fragments observed at the light and electron microscope levels were statistically significant. However, with
Published data are reviewed along with our own data on synaptic plasticity and rearrangements of synaptic organelles in the central nervous system. Contemporary laser scanning and confocal microscopy techniques are discussed, along with the use of serial ultrathin sections for in vivo and in vitro studies of dendritic spines, including those addressing relationships between morphological changes and the efficiency of synaptic transmission, especially in conditions of the long-term potentiation model. Different categories of dendritic spines and postsynaptic densities are analyzed, as are the roles of filopodia in originating spines. The role of serial ultrathin sections for unbiased quantitative stereological analysis and three-dimensional reconstruction is assessed. The authors data on the formation of more than two synapses on single mushroom spines on neurons in hippocampal field CA1 are discussed. Analysis of these data provides evidence for new paradigms in both the organization and ...
Single particle analysis is a group of related computerized image processing techniques used to analyze images from transmission electron microscopy (TEM). These methods were developed to improve and extend the information obtainable from TEM images of particulate samples, typically proteins or other large biological entities such as viruses. Individual images of stained or unstained particles are very noisy, and so hard to interpret. Combining several digitized images of similar particles together gives an image with stronger and more easily interpretable features. An extension of this technique uses single particle methods to build up a three-dimensional reconstruction of the particle. Using cryo-electron microscopy it has become possible to generate reconstructions with sub-nanometer resolution and near-atomic resolution first in the case of highly symmetric viruses, and now in smaller, asymmetric proteins as well. Single particle analysis can be done on both negatively stained and vitreous ...
Fenestrated blood vessels in the rat choroid plexus are permeable to dye-labelled proteins, HRP and ferritin. Most leakage appears to be via fenestrae but some additional escape of marker appears to take place through transient and reversible openings in the junctions between endothelial cells. After they have escaped into the choroidal stroma markers are prevented from entering the CSF by tight junctions between the epithelial cells which cover the choroid plexus, but how they are removed from the extravascular space is not known. Electron microscope study of rats who have been given multiple intravenous injections of ferritin shows that extravascular ferritin is take up both by connective tissue cells in the choroidal stroma and by choroidal epithelial cells. The findings suggest that the ingested protein is subsequently broken down within lysosomal vacuoles in the cytoplasm of these cells. Such intracellular digestion may be the major means of controlling the protein content of the extravascular
The interaction of electrons with solids are briefly reviewed with the emphasis given to elastically and inelastically scattered electrons and the origin of characteristic X-rays, which are used for chemical analysis in electron microscopy. The physical origin of image diffraction and phase contrasts in the transmission electron microscope are discussed. Special attention is paid to the formation of Kikuchi line diffraction patterns. In scanning electron microscopy, Kikuchi lines are used for all orientation imaging techniques (OIM /EBSD) which allow us to determine the orientation of grains and to establish the presence of textures. In the case of transmission electron microscopy, Kikuchi line diffraction patterns are used as crystallographic maps which allow to orient single crystals. It will be explained how simple two beam diffraction contrasts can be obtained and a brief introduction into stereographic 3D methods in scanning and transmission electron microscopy will be given. The students ...
We introduced several membrane-impermeant fluorescent dyes, including Lucifer Yellow, carboxyfluorescein, and fura-2, into the cytoplasmic matrix of J774 cells and thioglycollate-elicited mouse peritoneal macrophages by ATP permeabilization of the plasma membrane and observed the subsequent fate of these dyes. The dyes did not remain within the cytoplasmic matrix; instead they were sequestered within phase-lucent cytoplasmic vacuoles and released into the extracellular medium. We used Lucifer Yellow to study these processes further. In cells incubated at 37 degrees C, 87% of Lucifer Yellow was released from the cells within 30 min after dye loading. The dye that remained within the cells at this time was predominantly within cytoplasmic vacuoles. Lucifer yellow transport was temperature dependent and occurred against a concentration gradient; therefore it appeared to be an energy-requiring process. The fluorescent dyes used in these studies are all organic anions. We therefore examined the ...
The active zone is present in all chemical synapses examined so far and is present in all animal species. The active zones examined so far have at least two features in common, they all have protein dense material that project from the membrane and tethers synaptic vesicles close to the membrane and they have long filamentous projections originating at the membrane and terminating at vesicles slightly farther from the presynaptic membrane. The protein dense projections vary in size and shape depending on the type of synapse examined. One striking example of the dense projection is the ribbon synapse (see below) which contains a ribbon of protein dense material that is surrounded by a halo of synaptic vesicles and extends perpendicular to the presynaptic membrane and can be as long as 500 nm.[3] The glutamate synapse contains smaller pyramid like structures that extend about 50 nm from the membrane.[4] The neuromuscular synapse contains two rows of vesicles with a long proteinaceous band ...
A morphological and ultrastructural study on the prostate of a land snail Nesiohelix samarangae was conducted. The prostate of Nesiohelix samarangae is a tubular gland connected with the large hermaphrodite duct. The lining of the prostate tubules possesses two distinct types of epithelial cells, one secretory and the other non-secretory. The secretory cells contained numerous secretory granules in various sizes and electron density. Most of the secretory granules showed light electron density but some of them showed heavy density. The ciliated cells were non-secreting cells situated only toward the lumen of the tubules and appeared as ordinary epithelial lining cells. The ciliated cells of the epithelium extensively interdigitate with each other and their apical surfaces had numerous cilia and microvilli. The bases of the ciliated cells did not reach the basal region of the secretory cells ...
INTRODUCTION Familial benign hematuria (FBH) (MIM 141200) is an autosomal dominant disease. It is characterized by persistent or recurrent microscopic hematuria, not associated with other abnormalities such as renal failure or deafness1. The diagnosis of this benign disease may be difficult to establish, since it is based on a series of negative findings (absence of proteinuria, renal failure or extrarenal symptoms) and the finding of a non-specific ultrastructural lesion, the thin glomerular basement membrane (GBM), and above all on the results of family investigation demonstrating the absence of progression towards renal failure.. Early stages of Alport Syndrome (AS) can be very similar to FBH, both in its clinical features and the electron microscopic appearance.. AS can be inherited as an X-linked, autosomal dominant or autosomal recessive trait2. X-linked forms account for approximately 85% of AS cases and they are due to mutations in the COL4A5 gene. Autosomal dominant and recessive forms ...
Chair of Ultrapath XVIII - President-elect of the Society for Ultrastructural Pathology. Electron microscopy is a method whose importance for diagnosis and research in Pathology is well established. Unfortunately, the method remains poorly known by the medical profession and is often not part of the standard medical curriculum, precluding its widespread use in diagnosis. Further factors like the use of proper facilities and experience for performing ultrastructural diagnosis have to be addressed but are often underestimated. It is usually acknowledged that many diagnostic applications that in the past relied solely on electron microscopy methods have been replaced by simpler and more accessible methods like immunocytochemistry and molecular biology.. However it must be understood that electron microscopy is still the most reliable way to study macromolecular structure and its relationships within the cell. Electron microscopy is also a catch all method available at the ultrastructural level, ...
Application: To obtain a 3D model for objects that are too thick for single particle electron microscopy (≥ 1 micrometer thick), e.g., small cells, cellular organelles, macromolecules and their complexes, viruses. Method: Samples are vitrified by plunge freezing or by high-pressure freezing, cut into thin slices if necessary, and imaged at various tilt angles in the microscope using the lowest possible electron dose. Imaging under low dose conditions minimizes physical damage of the sample during data acquisition, but leads to extremely low signal-to-noise conditions. Sub-tomogram averaging recovers the signal by an intensive computational procedure, yielding structural resolutions of up to ~1 nm.. ...
To establish the methods of demonstrating early fixation of metal implants to bone, one side of a Cobalt-Chromium (CoCr) based alloy implant surface was seeded with rabbit marrow mesenchymal cells and the other side was left unseeded. The mesenchymal cells were further cultured in the presence of ascorbic acid, β-glycerophosphate and dexamethasone, resulting in the appearance of osteoblasts and bone matrix on the implant surface. Thus, we succeeded in generating tissue-engineered bone on one side of the CoCr implant. The CoCr implants were then implanted in rabbit bone defects. Three weeks after the implantation, evaluations of mechanical test, undecalcified histological section and electron microscope analysis were performed. Histological and electron microscope images of the tissue engineered surface exhibited abundant new bone formation. However, newly formed bone tissue was difficult to detect on the side without cell seeding. In the mechanical test, the mean values of pull-out forces were 77.15 N
Neural circuitry is determined primarily by trillions of synaptic junctions that link cells in the nervous system. Understanding how the structure of the synapse influences its function has been a central goal of cellular neuroscience since synapses were first recognized more than a century ago. Long-term potentiation (LTP), a long lasting enhancement of synaptic efficacy, is a well-characterized cellular correlate of learning and memory that results in dramatic structural remodeling of the synapse. Research has focused heavily on the postsynaptic structural remodeling that occurs to support LTP, but concomitant presynaptic and subcellular remodeling during LTP has been left largely unexplored. To address these questions, three-dimensional reconstructions from serial section electron microscopy of presynaptic boutons, vesicle pools, and dendritic smooth endoplasmic reticulum (SER) in hippocampal area CA1 were created and quantified. The data presented in this dissertation demonstrate that ...
Looking for interconnecting? Find out information about interconnecting. To attach one device to another. A physical port or wireless port used to attach one device to another Explanation of interconnecting
The CAMCOR Alice C. Tyler Nanofabrication and FIB-SEM Facility provides an array of equipment supporting high resolution electron microscopy, nanofabrication, and material characterization techniques. The facility offers high-resolution scanning electron microscopy and ion-beam microscopy services, as well as electron-beam, and ion beam lithography.. The facility is equipped to support sample types from multiple disciplines, providing sample preparation equipment and services for biological, materials, and geological applications.. ...
Myosin has been identified in a variety of non-muscle cells, and is believed to play a role in maintenance of cell shape, locomotion, cytokinesis, exocytosis and other cellular functions. In this paper we describe the purification of myosin from a pancreatic acinar-cell carcinoma of the rat which forms solid tumours, but retains many differentiated functions. The purified myosin was composed of a 200,000 Da heavy chain and two or three classes of light chains. Electron-microscopic examination of rotary-shadowed preparations revealed that individual molecules had two globular heads and a long tail measuring approx. 149 nm. The myosin was soluble in high-salt buffers and became sedimentable as the ionic strength was lowered. Examination of negative-stained preparations showed that this sedimentable myosin consisted of short, bipolar, thick filaments which had a strong tendency to aggregate in a head-to-head manner. The ATPase activity of the purified myosin was stimulated by EDTA or Ca2+, but not ...
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Mitochondria have a central importance: they use electron transport chains and their associated molecular machinery to synthesize ATPs, which provide energy to drive chemical reactions within all eukaryotic cells. Mitochondria are also involved in heme synthesis and lipid metabolism and are highly dynamic, resulting in either large or discrete structures or networks. Characterization of these networks within cells can provide important information about the cells metabolic activity and their overall viability. We have used serial block-face scanning electron microscopy (SBF-SEM) to analyze distributions of mitochondrial network lengths in several types of cells. SBF-SEM can provide high-resolution three-dimensional ultrastructure of large volumes of resin-embedded biological tissue or cells at the nanometer scale, making it possible to image samples extending over ,100 µm in three dimensions, at 10 nm spatial resolution in the plane of the block face (x and y) and 25 nm resolution in the ...
A process for producing flat products from particulate material comprises the steps of forming relatively smooth, castable slurry comprising a suspension of particulate material in an aqueous solution, a film-forming binder material and a dispersion of a particulate synthetic resin in an aqueous solution, depositing a coating of this slurry onto a support surface and, heating the deposited coating to a temperature at which a component of the synthetic resin volatilises. The coating may be removed from the support surface as a flat product either before or after heating to volatilize a component of the synthetic resin.
0046]While various materials have been identified as useful as either high or low threshold percolation concentration materials, as such high and low thresholds are relative terms, certain materials may be usable as either a low or high threshold material, depending upon the threshold percolation wt % concentration of the other conductive particulate material employed. In one embodiment of the invention, the relatively low threshold particulate material and the relatively high threshold particulate material are selected such that their threshold percolation weight percent concentrations are separated by at least 1 wt percent, preferably at least 2 wt percent, more preferably at least 5 wt percent, and most preferably at least 10 wt percent. In a further embodiment, the relatively low threshold particulate material and the relatively high threshold particulate material are selected such that the low threshold particulate material has a percolation threshold wt % concentration of less than 10 ...
In order to reveal the differentiation characteristics of organelles of ciliates under different physiological status, the cellular ultrastructure of Urostyla grandis was studied by transmission electron microscopy. In the resting cells most ciliary shafts, kinetosomes and sub-pellicle microtubules were resorbed, and the endoplasmic reticulum (ER) disappeared with the autophagocytosis taking place within the cytoplasm. As well, the nuclear matrix of the macronucleus was extruded into the cytoplasm, forming pseudopodia-like structures with large quantities of heterochromatin (CH) attached to the inner nuclear membrane. During excystment, membraneous structures developed and gradually increased in number to form the ER. Autophagic vacuoles (AVs) appeared containing mitochondria, paraglycogen particles (PGP), membranous structures, etc. Moreover, the number of nucleoli decreased with the chromatin, condensing in parallel with the process of recombination. Based on these observations, it could be ...
number we have found in this type of neuron is only 10-12. In longitudinal sections the fasciculated microtubules in the initial segment often appear darker than the single microtubules in the rest of the nerve cell and its processes. This appearance is due only partly to overlapping of the microtubules in a bundle within the thickness of the section. In addition, each microtubule is surrounded by a cloud of fine fibrillar material that contributes to the general density of the fascicle. In transverse sections it can be seen that the microtubules are arrayed close together in a curving and sometimes branching line (Figs. 3, 4, and 6). Single or isolated microtubules are rarely encountered in the initial segment. Favorably oriented transverse sections show that the microtubules within the fascicles are bound together by thin, dark crossbars or arms (Figs. 3 and 6). The bundling of the microtubules ceases abruptly at the beginning of the myelin sheath. Whether they continue down the axons as ...