bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of intermediate filaments in mature mammalian skeletal muscle by TEM
Authors: Yagyu Masako , Robson Richard M. , Stromer Marvin H. 
Published: June 2020

It is generally assumed that desmin in mature striated muscle cells is in the form of intermediate filaments (IFs) and that its primary locus is at or near the myofibrillar Z-lines. Although IFs have been identified by transmission electron microscopy (TEM) in embryonic and adult smooth and cardiac muscle cells and in differentiating or diseased skeletal muscle cells, IFs have rarely been unambiguously visualized in adult skeletal muscle (especially mammalian) cells by TEM. This is due in part to the small amount of IF protein in normal mature skeletal muscle, and in part to the heavily-packed, myofibril-dominated, intracellular cytoskeleton of these cells. In order to help ascertain the possible mechanism(s) of attachment of IFs to myofibrils, our objectives in this study were to identify, by TEM, IFs in adult mammalian skeletal muscle and to study the structural relationship of IFs and the muscle Z-lines.Samples of porcine semitendinosus muscle were removed from mature animals immediately after death, isometrically restrained and fixed in Karnovsky's fixative for 3 hours at 25°C, and processed by conventional methods followed by embedment in Epon-Araldite resin.
Actin and α-tubulin immuno-EM labelings reveal differences in intra versus interphotoreceptor matrix
Authors: Järvilehto Matti , Harjula Riitta 
Published: June 2020

The photoreceptor cells in the compound eyes of higher diptera are clustered in groups (ommatidia) of eight receptor cells. The cells from six adjacent ommatidia are organized into optical units, neuro-ommatia sharing the same visual field. In those ommatidia the optical axes of the photopigment containing structures (rhabdomeres) are parallel. The rhabdomeres of the photoreceptor cells are separated from each other by an interstitial i.e innerommatidial space (IOS). In the photoreceptor cell body, besides of the normal cell organelles, a cellular matrix is a structurally apparent component. Similar kind of reticular formation is also found in the IOS containing some unidentified filamentary substance, of which composition and functional significance for optical properties of vision is the aim of this report.The prefixed (2% PA + 0.2% GA in 0.1-n phosphate buffer, pH 7.4, for 1h), frozen section blocks of the compound eye of the blowfly (Calliphora erythrocephala) were prepared by immuno-cryo-techniques. The ultrathin cryosections were incubated with antibodies of monoclonal α-tubulin and polyclonal smooth muscle actin. Control labelings of excess of antigen, non-immune serum and non-present antibody were perforated.
The association of epizootic hemorrhagic disease virus with the cytoskeleton
Authors: Nunamaker R.A. , Wigington J.G. , Nunamaker C.E. 
Published: June 2020

The cells of eukaryotes are characterized by a filamentous network referred to as the cytoskeleton. It is believed that most animal viruses use the cytoplasmic or nuclear skeletal matrix during at least part of their replication cycle.Transmission electron microscopic studies of thin sections of cells infected with epizootic hemorrhagic disease virus(EHDV), a double-stranded RNA virus belonging to the Reoviridae family, have demonstrated the presence of virus-like particles, virus-specific fibrils and tubules, and viral inclusion bodies. Studies of bluetongue virus (a closely related orbivirus) by Eaton et al. and Hyatt et al. confirmed that these virus-specific structures bind to the cytoskeleton of infected cells, and facilitated study of their viral protein content using monoclonal antibodies in immunogold labeling procedures, This study describes cytoskeletal involvement in the replication of EHDV.The grid-cell-culture technique, preparation of cytoskeletons, and immunolabeling procedure were those described by Hyatt et al. Grids were dehydrated in a graded alcohol series, critical point dried in amyl acetate and CO2, coated with carbon and examined with a Philips LS 410 transmission electron microscope operating at 60 kv.
Ultrastructural characteristics on capillary of giant panda
Authors: Xiang-Yuan Zeng , Hang Chong , Wei Lian , Ke-juing Zhang 
Published: June 2020

Electron microscopic observation on ultrastructural characteristics of the capillary ofgiant panda was presented. The samples were taken from mesentery and another samples were taken from mucosa of intestine. They were fixed in 2.5% phosphatebuffered glutaraldehyde and 1% osmic acid, and dehydrated by graded series of acetone. Then they were embedded with Epon 812. For orientation under phasecontrast microscope, 0.5--1.0 u thick sections were prepared from the epoxyembedded material. After that, ultrathin sections (30-50) were taken with ultramicrotome LKB-V type and stained by uranyl acetate and lead citrate and examined under DXB2-12 Electron Microscope.Electron microscopic observation showed the capillary diameter in the mesentery microcirculation is larger and capillary wall is thin. The nucleus in endothelium was large and wasn't regular in the shape. Chromatin was loose in the nucleus. There was little plasma inthe endothelium and it looked loose. Organelles in the cytoplasm were little and vacuoles were more in endothelium. The distribution of plasma in the endothelium was different with endothelium of human body.
Application of Scanning Electron Microscopy for observing glomerulus maturation in human kidney
Authors: Hyodo Toru , Naguro Tomonori , Kameie Toshio , Iino Akihiro , Miyagawa Ikuo 
Published: June 2020

The ultrastructurg of the mammalian kidney has been explored by many authors, both in adult and fetal animals. As one of the most feasible means to elucidate the complicated three dimensional structure, scanning electron microscopy (SEM) has played an important role in the study of the kidney especially on the morphology of renal glomeruli. So far none of the authors has applied SEM to the human fetus for investigating the development of the glomerulus. In the present report SEM has been used to demonstrate the structure of human fetal metanephric glomeruli with special reference to the morphological differentiation of the podocyte.Materials and Methods: The metanephric kidneys were collected from 4 human fetuses ranging from 11 to 14 weeks of gestation, 2-12 h after death following therapeutic or spontaneous abortions. All specimens were fixed with 2.5% glutaraldehyde in phosphate buffer and cut into small pieces with a razor blade.
Structural analysis of the nuclear pore complex and its constituents unveils a pronounced asymmetry of its cytoplasmic and nucleoplasmic faces
Authors: Jarnik M. , Buhle E.L. , Reichelt R. , Engel A. , Aebi U. 
Published: June 2020

The nuclear pore complex (NPC) is an elaborate supramolecular organelle implicated in nucleocytoplasmic transport, enabling small molecules (diameter ≤ 9 nm) to pass freely while mediating active transport of larger molecules. By conventional transmission electron microscopy (CTEM) the NPC consists of 8 radial spokes surrounding a central channel, often appearing plugged, sandwiched between two concentric, 8-fold symmetric rings. Based on quantitative scanning trasmission EM (STEM), the intact NPC has a mass of 125 MD, the cytoplasmic ring (RC) of 32 MD, the nucleoplasmic ring (RN) of 21 MD, the plug-spoke complex (PS) of 65 MD, and the central plug (P) of 13 MD, indicating that molecularly, the NPC may easily contain 100-200 different polypeptides. Here we document the structural asymmetry of the RC and the RN by CTEM.Nuclear envelopes (NE) were manually isolated from Xenopus laevis oocytes and spread onto a carbon/colloidon-coated EM grid with the cytoplasmic side in contact. To obtain specimens comparable to those used for STEM, chemical fixation was omitted. Standard specimens were contrasted with 0.75% uranyl formate (UF) and air-dried.
Localization of pyroantimonate-precipitable calcium in biomineralization with special reference to the calcium carbonate crystals (otoconia)
Authors: Kawamata Seiichi 
Published: June 2020

Biomineralized tissues (otoconia, bones and teeth) incorporate and/or liberate a lot of Ca ion. However, the direct visualization of ionic and loosely-bound Ca has not been successful because of the hardness of these tissues. This problem was partly overcome in the present study. The pyroantimonate technique and a new demineralization method were successfully combined to visualize pyroantimonateprecipi table Ca in the organs where CaCO3 crystals are formed.Tree frogs, with or without 0.8% CaCl2 loading, were decapitated. Their spinal columns containing the endolymphatic sac were sliced and immersed in a fixative that contained 2% glutaraldehyde and 2% K-pyroantimonate in 0.05M K-phosphate buffer (pH 7.4). Rats (2 and 8 weeks of age) anesthesized with ether were perfused via left ventricle first with saline, followed by a fixative containing 3% glutaraldehyde and 2% K-pyroantimonate in 0.1M K-phosphate buffer (pH 7.4). The otolithic organs were removed and immersed in the same fixative. Specimens of the tree frogs and rats were postfixed in 1% OsO4 and 2% K-pyroantimonate.
Electron Microscopic studies on the antennal sensilla and the pheromone-producing glands of two important oil seed pests
Authors: Jamil Kaiser , Jyothi K.N. , Prasuna A.L. 
Published: June 2020

Sensory mechanisms underlying insect chemical communication have been given considerable attention in recent years. A study on the ultrastructural details of the antennal appendages and the pheromone producing structures of Achoea janata L. and Ophiusa algira were studied with scanning electron microscope in order to understand the mechanisms of olfactory perception and pheromone release.For fixation of pheromone producing glands of A.Janata and O.Algira the posterior region of the abdomen was pressed sufficiently and flooded with carnoys fluid for complete excedation of the 9th abdominal along with the ovipositor. The above specimens as well as the antennal appendages were then fixed in 4% glutaraldehyde in phosphate buffer of 7.2 pH dehydrated in increasing grades of ethylalcohol and critical point dried. The specimens were then coated with gold in vacuum evaporator and observed in a Hitachi S-520 evaporator and observed in a Hitachi S-520 SEM operated at 20KV.
New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques
Authors: Hayes S. F. , Corwin M. D. , Schwan T. G. , Dorward D. W. , Burgdorfer W. 
Published: June 2020

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.
High-pressure freezing and freeze substitution of teliospores of the rust fungus Gymnosporangium clavipes
Authors: Roberson Robert W. 
Published: June 2020

The use of cryo-techniques for the preparation of biological specimens in electron microscopy has led to superior preservation of ultrastructural detail. Although these techniques have obvious advantages, a critical limitation is that only 10-40 μm thick cells and tissue layers can be frozen without the formation of distorting ice crystals. However, thicker samples (600 μm) may be frozen well by rapid freezing under high-pressure (2,100 bar). To date, most work using cryo-techniques on fungi have been confined to examining small, thin-walled structures. High-pressure freezing and freeze substitution are used here to analysis pre-germination stages of specialized, sexual spores (teliospores) of the plant pathogenic fungus Gymnosporangium clavipes C & P.Dormant teliospores were incubated in drops of water at room temperature (25°C) to break dormancy and stimulate germination. Spores were collected at approximately 30 min intervals after hydration so that early cytological changes associated with spore germination could be monitored. Prior to high-pressure freezing, the samples were incubated for 5-10 min in a 20% dextran solution for added cryoprotection during freezing. Forty to 50 spores were placed in specimen cups and holders and immediately frozen at high pressure using the Balzers HPM 010 apparatus.
Staining terminal cisternae proteins in rat skeletal muscle triads: Selectivity of a new silver technique
Authors: J Tandler Carlos , de Iraldi Amanda Pellegrino 
Published: June 2020

A selective silver staining of proteins within the lateral components of triads and diads in fixed striated muscle cells and in isolated sarcoplasmic reticulum vesicles using a mercuric acetate postflxation has been demonstrated by us.In the present work we modify the technique in order to study the mechanism of the reaction . First, the mercuric postfixation step was omitted and replaced by a treatment with diluted ammonia, a procedure thought to wash out the excess of the reducing aldehyde fixative. Second, a treatment with mercuric acetate was employed on the ammonia treated muscles. The rat gastrocnemius muscle was fixed by immersion (12-24 h) in 3% glutaraldehyde, washed briefly with water and placed (12-24 h) into an ammonia:distilled water (1:4 v/v) solution. After washing with water, 1% acetic acid and water, muscles were treated overnight with 50% (v/v) ammoniacal silver nitrate at 37°C in darkness, washed with three changes of 5% (w/v) sodium sulphite and water, embedded in Poly B, sectioned and examined unstained with a Siemens Elmiskop I electron microscope.
Studies of anionic sites of the kidney by re-injection of polyethyleneimine (PEI) after disappearance of PEI-particles by initial administration
Authors: Nakono Kiyoko , Yoshimura Ashio , Oniki Hiroaki , Ideura Terukuni , Koshikawa Shozo 
Published: June 2020

As anionic sites of glomerular basement membrane (GBM) stained by intravenous injection of PEI became obscure 2 hours after administration, we studied reappearance of the anionic sites upon re-injection of PEI.The following two experimental groups were prepared: In group A; 10 rats were injected with 0.3ml of 0.5% PEI (MW=1,800) solution, and left nephrectomy was performed after 3 hours (group A-1, N=5) and 5 hours (group A-2, N=5). Each tissue samples was subjected to contrasting/fixation immersion, washing, post-fixation and staining. Immediately after nephrectomy, re-administration of 0.3ml of the same PEI solution was performed on each animal. Right nephrectomy was done 15 minutes after re-injection of PEI, and renal tissue was treated the same way as that of the left kidney (group A-1', group A-2'). In group B; PEI with a molecular weight of 70,000 was used. Injection of PEI solution, nephrectomy and treatment of renal tissues were carried out in the same way as for group A (group B-l and B-l', N=6; group B-2 and B-2', N=8).
A rapid fixation method for transmission and Scanning Electron Microscopy using microwave irradiation
Authors: Hotta Yasuaki , Nozaki Masumi , Honda Nobuhiko , Kato Hiroyuki , Wei Wang Ying , Watari Nakazo 
Published: June 2020

Recently, the validity of microwave irradiation (MWI) for electron microscopy has attracted special interest especially in Japan. Recently, we developed a new maceration method for scanning electron microscopy (microwave maceration) and a rapid polymerization method for tissue embedding using epoxy resin (microwave polymerization). Concerning the tissue fixations using MWI (microwave fixation), there are many problems which are not yet clear. In this study, we intend to reveal the effectiveness and mechanism of microwave fixation for scanning and transmission electron mi c roscopy.Liver and trachea taken from Wistar strain male rats were used in this experiment. The fresh livers and tracheae were cut into small pieces and microwave irradiated using a microwave processor (H2500, Bio-Rad) for 1 or 3 min in 2.5% g1utara 1dehyde (GL) bufferized fixatives regulated at pH 7.3 with 0.1M phosphate buffer solution. To prevent the rising of temperature during MWI, specially designed metal case containing water and ice was used (Fig.1).
Hepatotoxicity of rubber vulcanization fumes in rats
Authors: Rydzynski Konrad , Opalska Barbara , Czerczak Sławomir 
Published: June 2020

Rubber vulcanization fumes are one of the hazardous agents that occur in the workplace atmosphere in the rubber factories. Vulcanization processes generate a whole spectrum of vapours and gases, which contain, among others, benzene, benzo|a|pyrene and nitrozamines. The aim of the present study was to evaluate potential hepatoxic effects of acute and subchronic inhalatory exposures in rats.For that purpose Wistar rats were exposed in dynamic inhalation chambers to rubber vulcanization fumes for 4 hours, at the concentration of 2-3mg/l, (acute exposure) and for 6 hours daily, five times a week, for 28 days, at the concentration of 0.1mg/l (subacute exposure). Controls inhaled air at the same conditions. Liver samples were taken from rats directly after the end of both exposure types, and at 2nd and 14th day after acute exposure to study recovery processes, fixed, dehydrated and embedded according to conventional procedures. The number of fat-storing cells and Kupffer cells was estimated directly on JEOL JEM100C fluorescence screen screen at x2600 (measured area 7500 μm2), and relative volume of lipid droplets in hepatocytes and in fat-storing cells cytoplasm determined using point-counting analysis.
Biological and biomedical applications of collagenous biomaterials
Authors: Kato Yasushi P. , Dunn Michael G. , Silver Frederick H. , Wasserman Arthur J. 
Published: June 2020

Collagenous biomaterials have been used for growing cells in vitro as well as for augmentation and replacement of hard and soft tissues. The substratum used for culturing cells is implicated in the modulation of phenotypic cellular expression, cellular orientation and adhesion. Collagen may have a strong influence on these cellular parameters when used as a substrate in vitro. Clinically, collagen has many applications to wound healing including, skin and bone substitution, tendon, ligament, and nerve replacement. In this report we demonstrate two uses of collagen. First as a fiber to support fibroblast growth in vitro, and second as a demineralized bone/collagen sponge for radial bone defect repair in vivo.For the in vitro study, collagen fibers were prepared as described previously. Primary rat tendon fibroblasts (1° RTF) were isolated and cultured for 5 days on 1 X 15 mm sterile cover slips. Six to seven collagen fibers, were glued parallel to each other onto a circular cover slip (D=18mm) and the 1 X 15mm cover slip populated with 1° RTF was placed at the center perpendicular to the collagen fibers. Fibroblast migration from the 1 x 15mm cover slip onto and along the collagen fibers was measured daily using a phase contrast microscope (Olympus CK-2) with a calibrated eyepiece. Migratory rates for fibroblasts were determined from 36 fibers over 4 days.
SEM immunohistochemistry using alkaline phosphatase-labeled antibody
Authors: Hashimoto Hisashi , Hoshino Kazumasa 
Published: June 2020

Scanning electron microscopic immunohistochemical observations have been performed mainly using antibodies labeled by either virus particle or colloidal gold. In order to observe immunoreactive sites using these markers, however, high magnification is needed, even when the backscattered electron image (BEI) mode is utilized. Using alkaline phosphatase (ALPase)-labeled antibodies, lead phosphate can be deposited on immunoreactive sites and is detectable as strong signals on the BEI. Recent progress in computer technology enabled us to superimpose two or more images using different colors and gray levels. In this study, our attempt was made to detect the localization of prolactin cells in the pituitary gland and of laminin in the kidney using ALPase-labeled antibodies, by superimposing immunoreactive sites indicated by the BEI over their surface structures shown by the secondary electron image (SEI).Anterior pituitary glands obtained from female mice and kidneys from male mice were fixed by perfusion with 4% paraformaldehyde in 0.1M sodium phosphate buffer (SPB). After rinsing with 0.1M SPB, the fixed specimens were transferred into 50% dimethyl sulfoxide, frozen in liquid nitrogen and fractured, and rinsed with 0.1M SPB. The kidneys were pretreated with 0.1% pepsin in 0.01N HCl in order to have immunoreactivity against laminin restored.
Involvement of nucleus in the maturation of dengue-2 virus in C6/36 cells
Authors: Wang Jaang J. , Chen Cheng C. , Shaio Men F. , Liu Chia T. , Lee Chung S. , Yeh Ming Y. 
Published: June 2020

The involvement of nucleus in the maturation processes of Dengue-2 virus in a mosquito cell line, C6/36 cells, has been identified by the electron microscopy and immunocytochemistry. The C6/36 cells were obtained from ATCC and maintained in MEM culture medium containing 10% fetal bovine serum at 28°C. The cell suspensions or cells grown on teflon-coated coverslips were infected with Dengue-2 virus (107/ml) for various time periods of 2 hours, 3, 6, 8, and 10 days. The cells were then fixed in buffered 1.5% glutaraldehyde, and washed in acetone before immunolabeled with monoclonal antibody. An indirect immunocytochemical labeling method of avidin-biotin complex (ABC) conjugated with peroxidase or gold particles (20 nm in diameter) and a flat embedding technique were used to localize the virus particles.At early stages of infections (before 3 days), there were no virion particles detected. After 6 days and on of infections, cytopathic effect (CPE) was observed and showed positive immuno-peroxidase reactions under the light and electron microscopies.
Improved immunolabelling of ultrathin cryosections using antibody conjugated with 1nm gold particles
Authors: Nielsen Morten H. , Bastholm Lone 
Published: June 2020

During the last 5 years the diameter of the gold probes used for immuno-cytochemical staining at the electron microscopical (EM) level has been decreased. The advantage of small diameter gold probes is an overall increased labelling density. The disadvantage is a lower detectability due to the low electron density of smaller gold particles consequently an inconvenient high primary magnification needed for EM examination. Since 1 nm gold particles are barely visible by conventional EM examination the need for enlargement by silverenhancement of the gold particles has increased.In the present study of ultrathin cryosectioned material the results of immunostaining using 5 nm gold conjugated antibody and 1 nm gold conjugated antibodies are compared after silverenhancement of the 1 nm gold particles.Slices of freshly isolated mouse pituitary gland were immersion fixed for 20 min in 2 % glutaraldehyde /2 % paraformaldehyde. Blocks cryoprotected with 2.3 M sucrose were frozen in liquid nitrogen and ultra-cryosectioned on a RMC cryoultra-microtome.