bluuebunny/crossref_metadata_2025_split huggingface dataset:
An investigation of experimental factors affecting the identification of enteroviruses by immunoelectron microscopy
Authors: Lee F. K. , Anderson N. , Doane F. W. 
Published: June 2020

In 1973 Anderson and Doane described a rapid method for serotyping enteroviruses on the EM grid, using immunoelectron microscopy (IEM). By mixing an unknown viral isolate with individual or pooled enterovirus antisera, the resulting typing test could be read by electron microscopy, using the presence of virus-antibody aggregates as indication of a positive result. The reaction was found to be serotype specific when tested with a wide range of enteroviruses (coxsackie, polio, echo). These results were in contrast to those obtained earlier by Chaudhary et al., who observed cross-reactivity among enteroviruses using IEM. In light of the potential usefulness of this method for rapid virus diagnosis, a study was carried out on some of the experimental factors that might affect the reliability of enterovirus serotyping by IEM.The most important factor in avoiding heterologous cross reactions was found to be the concentration of antiserum. As shown in Table I, when antisera were used at low dilutions they produced aggregation not only with the. homologous virus but also with the heterologous strains.
Permissivity of cerebellar explants for neurotropic viruses
Authors: Fournier J. G. 
Published: June 2020

Cerebellar explants from 3 days old new born hamsters were infected with a viral suspension of 105 PFU/mI for measles virus and 106 for herpes (HSV 2) virus.Under measles virus infection, nucleocapsids were observed after 10 days in the cytoplasm under the form of paracristalline structures (Fig. 1), sometimes associated with hidding of the cell surface. After 20 days nucleocapsids were also observed in the nucleus.Under HSV infection cell lysis occured within 48 hours and was preceded by extensive production of nucleocapsids (Fig. 2). Maturation of the particles was visible in the nuclear envelope and the cell membranes.In both infections the apparition of nucleocapsids was correlated with cellular changes, especially in the nucleus. Most alterations were observed in the chromatin, the nucleolus and perichromatin granules. The cell type, glial or neuronal, of the infection was analyzed.
Sendai virus maturation in actinomycin D pretreated and glutamine starved 37 RC and vero cells
Authors: Djaczenko Wiktor , Benedetto Arrigo , Stefania Zaniratti Maria 
Published: June 2020

Actinomycin D (AMD) pretreatment (0. 5 μg/ml, 72h) causes surface glycoprotein accumulation in 37 RC and Vero cells (submitted for publication). On the other hand glutamine starvation in these cells does not inhibit the cell replication but reduces the cell adhesiveness to the plastic and glass substrates probably by depletion of glucosamine pool. In such metabolic conditions the modifications of plasma membrane flexibility could be expected. Since such a flexibility influences Sendai virus maturation we decided to study the replication of this virus in AMD pretreated and glutamine starved cells.Three groups of 37 RC and Vero cells grown in monolayers, one untreated control, one AMD pretreated and one glutamine (G) starved were infected with Sendai virus. At 3. 5h and 24 h of infection corresponding cultures were fixed by: (a) classical methods, (b) TAPO techniqe and (c) ruthenium red method.
High resolution surface structure of foot-and-mouth disease virus
Authors: Breese S. S. , Bachrach H. L. 
Published: June 2020

Models for the structure of foot-and-mouth disease virus (FMDV) have been proposed from chemical and physical measurements (Brown, et al., 1970; Talbot and Brown, 1972; Strohmaier and Adam, 1976) and from rotational image-enhancement electron microscopy (Breese, et al., 1965). In this report we examine the surface structure of FMDV particles by high resolution electron microscopy and compare it with that of particles in which the outermost capsid protein VP3(ca. 30, 000 daltons) has been split into smaller segments, two of which VP3aand VP3bhave molecular weights of about 15, 000 daltons (Bachrach, et al., 1975).Highly purified and concentrated type A12, strain 119 FMDV (5 mg/ml) was prepared as previously described (Bachrach, et al., 1964) and stored at 4°C in 0. 2 M KC1-0. 5 M potassium phosphate buffer at pH 7. 5. For electron microscopy, 1. 0 ml samples of purified virus and trypsin-treated virus were dialyzed at 4°C against 0. 2 M NH4OAC at pH 7. 3, deposited onto carbonized formvar-coated copper screens and stained with phosphotungstic acid, pH 7. 3.
Electron investigations of rhabdovirus-like particles in mexican bean beetles and crickets
Authors: Adams J. R. , Tompkins G. J , Heimpel A. M. , Dougherty E. 
Published: June 2020

As part of a continual search for potential pathogens of insects for use in biological control or on an integrated pest management program, two bacilliform virus-like particles (VLP) of similar morphology have been found in the Mexican bean beetle Epilachna varivestis Mulsant and the house cricket, Acheta domesticus (L. ).Tissues of diseased larvae and adults of E. varivestis and all developmental stages of A. domesticus were fixed according to procedures previously described. While the bean beetles displayed no external symptoms, the diseased crickets displayed a twitching and shaking of the metathoracic legs and a lowered rate of activity.Examinations of larvae and adult Mexican bean beetles collected in the field in 1976 and 1977 in Maryland and field collected specimens brought into the lab in the fall and reared through several generations revealed that specimens from each collection contained vesicles in the cytoplasm of the midgut filled with hundreds of these VLP's which were enveloped and measured approximately 16-25 nm x 55-110 nm, the shorter VLP's generally having the greater width (Fig. 1).
Surface structure of the bacteriophage λ head: location of the gpD
Authors: Wurtz M. , Imber R. , Tosi M. , Hohn T. 
Published: June 2020

The mature bacteriophage λ head contains two major proteins: gene products E and D (gpE and gpD). These proteins are arranged in a composite (gpE/gpD ratio = 1/1) T=7 icosahedral surface lattice.In previous studies using tubular head related forms, “polyheads”, we had proposed models for head maturation and structure. But with the methods used, it was not possible to localize unambiguously the position of the gpD clusters added during the last steps of the head maturation. New experiments are performed to choose between the two different models previously proposed.In a first step we have analysed with optical filtration some structures obtained after self-assembly of guanidine hydrochloride dissociated heads. One sided preferentially stained polyhead (Fig. 1) or monolayer (sheets) (Fig. 2) show the triangular shape clusters which could be the gpD trimers. We were able to get some improvement of the resolution of normal polyhead images by removal of associated debris with a mild treatment of citraconyl anhydride (10 mg/mg of polyhead) before preparing the specimen for the conventional electron microscope (Fig. 3) or the scanning transmission electron microscope (Fig. 4).
Ultrastructure of diplodia maydis infection process in zea mays
Authors: Murphy Judith A. , Thompson Mary R. , Pappelis A. J. 
Published: June 2020

Diplodia maydis(Schw.)Lev.is one of the major pathogens causing stalk rot of corn (Zea mays L), a complex disease resulting in an annual loss of more than one billion bushels of corn. Many studies concerning resistance or susceptibility of corn to D. maydis have been reported but none at the ultrastructure level. Because of the importance of D. maydis as a pathogen, it was the purpose of this study to investigate the host- parasite relationship, to elucidate the penetration phenomenon at the ultrastructural level, and to study any changes apparent in the host cell wall and in the fungal cell during the infection process.Samples for TEM were fixed in cold 3% buffered glutaraldehyde, buffer washed 3-6 times and post-fixed in 1% OSO4. Samples were then dehydrated through a graded EtOH series and propylene oxide and embedded in Epon-Araldite. Sections were cut on a Reichert 0m U2,stained with uranyl acetate/lead citrate or dipotassium tetramethyl osmate and examined in an Hitachi HU11AB at 50 KV.
Membrane biogenesis on isolated protoplasma surface
Authors: Salyaev R. K. , Chernyshov V. I. , Kuzevanov V. Ya. 
Published: June 2020

A number of papers show the formation of a new membrane on the surface of protoplasm run out after cutting of Characeae alga cells in a medium containing bivalent cations.The drops of isolated protoplasm were prepared by cutting of Nitella cells in a special decompression chamber under the conditions of turgor pressure compensation. The drops were transferred into agar microcapsules (Fig. 1), the preparation of which was described in detail earlier (Salyaev, 1968). The walls of agar microcapsule were transparrent therefore protoplasm drops were clearly observed in a light microscope (Fig. II). All other operations such as fixation, dehydratation and embedding in epoxy resins were made in agar microcapsule.Electron microscopic investigation revealed that the method of a drop preparation preserved all components of a protoplasmic ultrastructure: endoplasmic reticulum, ribosomes, mitochondria etc., the hyaloplasm being rather hydrated (Fig. III). The surface of isolated protoplasmic drop was shown to be a typical membrane 80-90Åthick (Fig. IV).
In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.
Authors: Reis D. , Vian B. , Roland J. C. 
Published: June 2020

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.
Mucosubstances of the granulocytes studied by means of electron microscopic radioautography and X-ray microanalysis
Authors: Murata F. , Yoshida K. , Ohno S. , Nagata T. 
Published: June 2020

As a series of histochemical studies on the mucosubstances of the granulocytes in this laboratory, the results obtained by electron microscopic radioautography and X-ray microanalysis have been reported.The femur bone marrows of adult rabbits weighing 1. 0-1. 5kg were diced into small pieces and incubated for 10, 30 and 60 minutes in Eagle's MEM supplemented with 10 % bovine serum, containing radioactive carrier free sulfuric acid at a concentration of lmCi/ml. They were fixed doubly in glutaraldehyde buffered with 0. 1 M phosphate buffer (pH 7. 2) and osmium tetroxide buffered with 0. 1 M phosphate buffer(pH 7. 2), dehydrated through a graded series of ethanol and acetone and embedded in Epon. Ultrathin sections were cut with an LKB ultrotome and radioautographed with Sakura NR-H2 emulsion by wire loop method, exposed for 127-203 days, developed with phenidone developer after gold latensification, stained with lead citrate and observed in Hitachi HS-9 electron microscope.
The cytoskeleton of human platelets at rest and after spreading: whole mounts viewed at 200 KV correlated with negatively stained specimens examined at 50 KV
Authors: Nachmias V. T. , Sullender J. S. 
Published: June 2020

New morphological approaches are needed to determine what changes take place in the cytoskeleton of platelets during activation by spreading or by agonists, for little information can be gained from thin sections alone. For whole mount study, we fixed platelets in plasma at 37°C very briefly with 0. 1% or 2. 5% formaldehyde freshly prepared from paraformaldehyde. We deposited the platelets on carbon-substrated grids, lysed them with 1% triton X 100, critically point dried them and examined them without staining in a JE0L JEM 200A electron microscope at 200 KV. These specimens were compared with unfixed platelets lysed with 1% triton-X 100 and subsequently negatively stained with 2% uranyl acetate and examined at 50 KV.Discoid, resting platelets fixed in suspension and viewed as whole mounts contained a dense interior which was removed to a variable degree by the lytic agent. In favorable specimens, the interior was observed to be made up of globular masses which could be roughly divided into two size classes
The developing nephron of the sea lamprey during metamorphosis
Authors: Ooi E. C. , Youson J. H. 
Published: June 2020

The definitive opisthonephric kidneys of lamprey each contains a single renal corpuscle with multiple nephric capsules surrounding a single compound glomerulus (glomus), which extends the length of the kidney. Each nephric capsule possesses a visceral layer of podocytes and a parietal layer continuous with the tubular epithelium. The development of these renal corpuscles and proximal portions of the tubules in the sea lamprey, Petromyzon marinus L., during metamorphosis was studied using electron microscopy.The nephron rudiments of the definitive opisthonephros arose as condensations of undifferentiated cell mass (Fig. 1) closely associated with the peritoneum. The differentiation of nephron rudiments along the entire nephrogenic cord was initiated synchronously at the onset of metamorphosis resulting in a series of rudimentary nephron units (RNU) which formed connections with the archinephric duct. The branching of RNU gave rise to secondary and tertiary rudimentary nephrons which radiated semicircularly from the original point of attachment to the peritoneum.
Fine structural, cytochemical, and phagocytosis studies of sinusoidal cells (SLC) of the mouse liver
Authors: Stöhr G. , Fahimi H. D. 
Published: June 2020

The mononuclear phagocytes of the rat liver (Kupffer cells) contain an endogenous peroxidase in the endoplasmic reticulum (ER) and nuclear envelope (NE). Phagocytosis studies have revealed that large latex particles (0. 8)μm) are exclusively phagocytized by such peroxidase positive cells. In view of known species differences in localization of peroxidase in mononuclear phagocytes, and since most immunological studies are performed in mice, we have investigated the localization of endogenous peroxidase in SLC of the mouse liver.Livers of male and female Swiss albino mice weighing 25-35 g were fixed by perfusion through the portal vein for 5 min. using 1. 0-5. 0% purified glutaraldehyde buffered with Na-cacodylate, pH 7. 2. Two min. prior to fixation some animals were given an intravenous'injection of 0. 8 μm latex particles (0. 05 ml/100 g). Fifty micron chopper sections were incubated for localization of endogenous peroxidase, followed by processing for electron microscopy.
Incidence of non-specific esterase during cleavage of rat ovum
Authors: Trávník Pavel 
Published: June 2020

For the study of non-specific esterase on electron microscopic level the method with incubation medium described by Hanker et al. (1972) and modified by Trávník (1977) was used. The object of the study was the 1-,2-,4-,8-cell rat ovum, early and late blastocyst. To differentiate organophosphate sensitive and organophosphate resistant esterases, inhibition by means of diethyl-p-nitrophenyl phosphate (E 600) was used in the concentration of 10μ mol/1. As substrates thionaphthylacetate (TNA) at pH 7 and thioacetoxybenzanilide (TAB) at pH 5.6 were used.Distinct activity of organophosphate sensitive esterase has been proved in aggregations of vesicles and tubules of smooth endoplasmic reticulum (Fig. 1). In the course of cleavage the total organophosphate sensitive activity is reduced together with the decrease in the amount of the smooth endoplasmic reticulum. In our opinion the aggregations of vesicles of smooth endoplasmic reticulum represent the site of reserve of hydrolytic enzymes synthetized during oogenesis, as a similar trend has been observed also in acid and alkaline phosphatases (astná 1977, 1978).
Three dimensional analysis of the eggshell fromDrosophila melanogaster
Authors: Margaritis Lukas H. , Kafatos Fotis C. 
Published: June 2020

Formation of the insect eggshell is being studied as a model case of cell differentiation. Because of the potential for genetic analysis, we are concentrating on the eggshell ofDrosophila melanogaster. Here we summarize our understanding of the wild type structure as determined using a variety of ultrastructural methods. Follicles, eggshells or pure endochorion were prepared as described and studied with a Philips 301 TEM, an AMR 1000 SEM, a JSM-35 SEM, and a JEM-1000 high voltage electron microscope. Glutaraldehyde fixation (Figs. 6, 8, 9) followed by OsO4, (Figs. 1, 3, 4, 7, 10, 11) was used.Thin sections (Fig. 1) of stage 14 follicles reveal the following layers of the mature eggshell from the oocyte surface outwards: vitelline membrane (VM), intermediate chorionic layer (ICL), endochorion (END) and exochorion(EX). The amorphous VM and the loosely fibrous EX appear simple in structure. The ICL has been purified and shown by negative staining to have a prominent crystalline structure (Fig. 2) which has been further investigated by optical diffraction and filtering.
Neuron-glia relationship during the early postembryonic development of the nervous system in some oligochaetes
Authors: Djaczenko Wiktor , Calenda Cimmino Carmen 
Published: June 2020

The simplicity of the developing nervous system of oligochaetes makes of it an excellent model for the study of the relationships between glia and neurons. In the present communication we describe the relationships between glia and neurons in the early periods of post-embryonic development in some species of oligochaetes.Tubifex tubifex (Mull. ) and Octolasium complanatum (Dugès) specimens starting from 0. 3 mm of body length were collected from laboratory cultures divided into three groups each group fixed separately by one of the following methods: (a) 4% glutaraldehyde and 1% acrolein fixation followed by osmium tetroxide, (b) TAPO technique, (c) ruthenium red method.Our observations concern the early period of the postembryonic development of the nervous system in oligochaetes. During this period neurons occupy fixed positions in the body the only observable change being the increase in volume of their perikaryons. Perikaryons of glial cells were located at some distance from neurons. Long cytoplasmic processes of glial cells tended to approach the neurons. The superimposed contours of glial cell processes designed from electron micrographs, taken at the same magnification, typical for five successive growth stages of the nervous system of Octolasium complanatum are shown in Fig. 1. Neuron is designed symbolically to facilitate the understanding of the kinetics of the growth process.
Cell junctions in the compound eye of the worker honey bee
Authors: Nickel E. , Scheck G. 
Published: June 2020

The ommatidium of the compound eye of the honey bee consists of visual or retinula cells which form a fused rhabdom. Each ommatidium contains three types of receptors which are sensitive to u. v., blue or green light. The ommatidium is isolated from its neighbours by secondary pigment cells.Electrical recordings from single retinula cells have shown sensitivity curves with double peaks. Basicly these two peaks can arise from two different photopigments in one receptor cell or from electrical coupling between two receptor cells of different spectral sensitivity.The present electron microscopic study was carried out in order to search for Junctional specializations between different cells in the ommatidium of the worker bee. These junctions are of particular functional interest because of their role in restricting extracellular fluid movement as well as in electrical coupling between cells. In freeze-cleaved specimens intercellular junctions can be identified on the characteristic array and size of intramembranous particles.
A scanning electron microscope technique for identifying myelinated axons
Authors: Friedman Peter 
Published: June 2020

A technique is presented here which facilitates the identification of myelinated axons in human spinal nerves and spinal cord using the scanning electron microscope (SEM). By examining the backscattered electron (BSE) image of a modified osmium-thiocarbohydrazide-osmium (OTO) treatment the myelin sheaths of individual axons can be identified.Two factors contribute to this BSE imaging: 1) multiple layers of osmium (mediated by the osmiophilic ligand thiocarbohydrazide, NH2NHCSNHNH2) are deposited in the tissue during the 0T0 treatment, and 2) since the myelin sheath contains the greatest concentration of unsaturated lipids, it incorporates more osmium than any other neural structure. This enhanced mass-density of the myelin sheath will then be imaged in the BSE mode of the SEM as a brighter area due to the greater number of primary electrons being backscattered by the osmium.
Electron microscope study on the glial filaments of astrocytes in the rat brain
Authors: Mori S. , Furukawa K. , Abe H. 
Published: June 2020

With the electron microscope, it was demonstrated that the glial filaments existed in astrocytes and could be impregnated by Cajal's gold chloride sublimate solution. By this conspicuous structure of glial filaments, thus, the astrocytes have long been differentiated from other glial cells from the classical light microscopic studies till the recent electron microscopic observations. Further investigations could add the new knowledge on this important component of glial cells in this laboratory that the actin- like filaments might be contained among the glial filaments. It will be shown in this report that glial filaments of astrocytes are consisted of the heterogenous groups of filaments, and some of them can bind with the heavy meromyosins (HMM).Normal rats (about 120 g body weight) were anesthetized with Nembutal and fixed by perfusion through the heart for 30 minutes with the fixative. This fluid was consisted of 3 % glutaraldehyde, 2 % paraformaldehyde, 4 % sucrose and 0. 5 mM CaCl2 in 0. 1 M phosphate buffer at PH 7. 4.
Ultrastructural studies of pigmented, depigmented and melanomatous skin in lipizzaner horses.
Authors: Gebhart W. , Niebauer G. 
Published: June 2020

Lipizzaner horses - as well as some other graying breeds - undergo progressive depigmentation of their coat color and are regularily affected by melanotic tumors at older age. Although deeply pigmented at birth nearly all individuals loose their dark color at the age of 4 — 6 years and multiple melanotic tumors arise in skin. Unique melanomatosis is frequently present in 20 — 30 years old animal (Gebhart and Niebauer, 1977). These characteristics design the horses of the genetically well-defined Lipizzaner breed as a suitable animal model for studies on depigmentation and tumor formation processes. Histochemical and ultrastructural investigations were performed in order to elucidate the morphological substrates of pigmented and depigmented lesions.Biopsy specimens were obtained by surgical excision from pigmented and depigmented skin and from melanomas of 19 Lipizzaner horses. Immediately after excision the tissue was devided into several portions and processed for routine histology, DOPA-reaction and electron microscopy. Ultrastructural investigations were performed in a ZEISS EM 9S2 and a JEOL lOO C TEMSCAN electron microscope fitted with a computer based energy-dispersive spectrometer (LINK).