bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron microscope study of the secretory activity of epithelial cells in embryonic thymus
Authors: Alasam H. 
Published: June 2020

The possibility that intrathymic T-cell differentiation involves stem cell-lymphoid interactions in embryos led us to study the ultrastructure of epithelial cell in normal embryonic thymus. Studies in adult thymus showed that it produces several peptides that induce T-cell differentiation. Several of them have been chemically characterized, such as thymosin α 1, thymopoietin, thymic humoral factor or the serum thymic factor. It was suggested that most of these factors are secreted by populations of A and B-epithelial cells.Embryonic materials were obtained from inbred matings of Swiss Albino mice. Thymuses were disected from embryos 17 days old and prepared for transmission electron microscopy. Our studies showed that embryonic thymus at this stage contains undifferentiated and differentiated epithelial cells, large lymphoblasts, medium and few small lymphocytes (Fig. 5). No differences were found between cortical and medullary epithelial cells, in contrast to the findings of Van Vlietet al,. Epithelial cells were mostly of the A-type with low electron density in both cytoplasm and nucleus. However few B-type with high electron density were also found (Fig. 7).
Surface morphology of Purkinje cells and myocardial cells following chemical digestion
Authors: Morita Tetsuo , Shimada Tatsuo 
Published: June 2020

From light and transmission electron microscopic studies, it has been long known that Purkinje cells of mammalian hearts have morphological characteristics different from ordinary myocardial cells. In the present study, not only Purkinje cells and myocardial cells but also connective tissue sheaths surrounding these cells were investigated by combined scanning electron microscopy(SEM) and chemical digestion.The moderator band of adult sheep heart was used because it possessed both Purkinje cells and myocardial cells (Fig.1). Tissue blocks were immersed in Karnovsky’s fixative for 3hr or longer. Some fixed tissues were inrrtersed in a 3-5% aqueous solution of NaClO for 1 min to digest the endocardial endothelium, and then were treated with 8N HCl for 30 min at 60°C to remove connection tissue elements. The others were iirmersed in a 2N NaOH or KOH solution for 7 days at room temperature to digest cellular elements. After freeze-cracking in a 40% dimethyl sulfoxide solution, the tissues were washed throughout in a saline solution containing tween 20, placed in a 1% aqueous solution of tannic acid for 2hr and conductive-stained with 1% OsO4 for 2hr.
Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)
Authors: Anna Pabst Maria 
Published: June 2020

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).
Actin filaments may be involved in the morphological changes of the urinary bladder transitional epithelium
Authors: Seguchi Harumichi , Kobayashi Toshihiro , Okada Teruhiko , Xin Zhang Shu , Garcia del Saz Eva 
Published: June 2020

In addition to the unique configuration of the luminal plasma membrane(1), the transitional epithelium of the urinary bladder is characterized by the presence of large numbers of microfilaments. These filaments can be divided into two groups: those of 5 nm, and others of 10 nm in diameter(2). In the present study, these filaments were identified by immunohistochemistry and by the HMM binding technique. Quick-freeze, deep-etching replicas were employed to reveal their three-dimensional arrangement.Light microscopically, the anti-actin immunoreaction was observed in the epithelial layer, as well as in the lamina muscularis mucosae and in the muscular layer. The intensity of the fluorescence in the superficial cells was weaker than in the intermediate and basal cells. The staining pattern of FITC-labeled phalloidin in the urinary bladder was very similar to that of anti-actin. The immunofluorescence of anti-cytokeratin antibody was exclusively observed in the epithelial layer of the urinary bladder. The reaction was evenly distributed throughout the epithelium.
Ultrastructural characteristics of hyaline cells in chick inner ear
Authors: Oesterle E.C. , Cunningham D.E. , Rubel E.W 
Published: June 2020

Recent light-microscopic autoradiographic investigations of the chick auditory end organ suggest that several types of supporting cells adjacent to the receptor end organ, i.e., hyaline cells and/or cuboidal cells, may be precursor cells for regenerating hair cells and supporting cells. Little is known regarding these supporting-cell types. The present study investigated ultrastructural properties of hyaline cells with TEM. Inner ears from four 10-day-old chickens were perfused with a mixture of 2% paraformaldehyde and 2.5% glutaraldehyde in 0.1 M cacodylate buffer. After washes in buffer (0.1 M cacodylate), end-organ dissection, osmication, dehydration in alcohol, and Epon embedding, series of semi-thin (1 um) and ultrathin sections (90 nm) were made, stained with uranyl acetate and lead citrate and observed with a Philips EM 410. Sections from high, mid, and low-frequency regions of the papilla were examined.A light microscopic picture of the inner ear of birds is shown in Figure 1. Hyaline cells are a single layer of cuboidal epithelial cells which rest on the basilar membrane and extend up to the scala media space.
Ultrastructural studies of the relationship between actin filaments and secretory granules
Authors: Holm Nielsen Ellen 
Published: June 2020

In secretory cells a dense and complex network of actin filaments is seen in the subplasmalemmal space attached to the cell membrane. During exocytosis this network is undergoing a rearrangement facilitating access of granules to plasma membrane in order that fusion of the membranes can take place. A filamentous network related to secretory granules has been reported, but its structural organization and composition have not been examined, although this network may be important for exocytosis.Samples of peritoneal mast cells were frozen at -70°C and thawed at 4°C in order to rupture the cells in such a gentle way that the granule membrane is still intact. Unruptured and ruptured cells were fixed in 2% paraformaldehyde and 0.075% glutaraldehyde, dehydrated in ethanol. For TEM (transmission electron microscopy) cells were embedded in Lowicryl K4M at -35°C and for SEM (scanning electron microscopy) they were placed on copper blocks, critical point dried and coated. For immunoelectron microscopy ultrathin sections were incubated with monoclonal anti-actin and colloidal gold labelled IgM. Ruptured cells were also placed on cover glasses, prefixed, and incubated with anti-actin and colloidal gold labelled IgM.
Effects of gamma radiation on muscle ultrastructure and proteinase activity of grass shrimp (Penaeus monodon F.)
Authors: Perng Fang-Shiow , Yang Jui-Sen 
Published: June 2020

Effects of irradiation on ultrastructural changes and proteinase activity of grass shrimp during storage was investigated. Shrimps were irradiated by a 60Co radiation source (total radioactivity 143 KCi and irradiation dose rate 3.0 KGy/hr) at a dose of 40 KGy at frozen temperature. Tissue pieces from the first abdominal segment of the shrimps were primarily fixed in 4 % glutaraldehyde (in 0.1 M K-phosphate buffer containing 3.04 % NaCl and 0.02 % CaCl2, pH 7.2), postfixed in 1 % OsO4, and dehydrated in acetone series and embedded in Spurr’s resin. Sections were stained with uranyl acetate and lead citrate and examined in a Hitachi H-600 transmission electron microscope operated at 75 KV.Small pieces of muscle were dissected from living grass shrimps and immediately incubated with 5 ml of shrimp body fluid for 30 minutes. The body fluid was released from irradiated whole shrimps after storage at ambient temperature for three weeks. The muscle pieces were also incubated with crude proteinase extracted from irradiated hepatopancreas dissected from shrimps or proteinase (EC 3.4.4.16) from Bacillus licheniformis. After incubation the ultrastrucutre of the muscles was prepared for examination by electron microscopy.
Ultrastructure of the miracidium of Schistosomia japonicum
Authors: Jamuar M. P. 
Published: June 2020

Miracidium is the first larval stage emerging frcm the egg produced in the vertebrate host in the life cycle of a Schistosome. They have to find a particular species of snail (the Intermediate host) within few hours for the continuation of the life cycle of the parasite and for which they have to be well equipped. Cilia helps them in the movement and sensory organs aid in locating the host. Some cytolytic substance producing glands helps in their penetration into the host.Miracidia were obtained from livers of mice infected 2 months previously with cercaria of Schistosoma japonlcum, in the Department of Microbiology, University of Chicago, Chicago, USA. The Miracidia were fixed in freshly prepared 6% Glutaraldehyde in 0.2 M phosphate buffer at pH 7.6 at 4°C for 2 hr. and were post fixed for 1 hr. in 1% Os O4 in the same buffer. They were washed twice with double distilled water and dehydrated in graded series of ethanol.
SEM studies of architecture of thoracic chelate appendages of fresh-water prawn, Macrobrachium lamarrei H.M. Edwards (Decapoda-Palaemonidae)
Authors: Sharma U. D. , Shukla Sanjive 
Published: June 2020

Chelate legs of certain crustaceans help in detection and capture, and finally carry the food to the trophic devices. The first and second pair of chelate leges (Periodpods) of M. lamarrei were studied to understand their role in food manipulation. These appendages were detached from the prawn, fixed, and processed. Samples were observed and photographed under an SEM (JEOL JSM 35C).Six types of bristles/setae have been observed on these podomeres (Figs. 1-11). However, the bristles on podomeres of the second leg are sparsely arranged. The toothed and serrate setae are also missing from the propodite of the second leg. The aboral and adoral surfaces of propodite of I chelate leg have two different types of sensory bristles. The serrate setae are aboral, each with a central shaft (120 μm long) and bilateral projections (15.5. μm long); the adoral ones are toothed setae (297 μm) with sunken base and denticulation at the distal end. A third type, the sawtoothed setae, are on the proximal part of the dactylopodite. These are arranged in 7-8 rows of 4-9 setae each.
An ultrastructural study on the shark liver
Authors: Yamada Masako , Tanuma Yutaka 
Published: June 2020

Although many fine structural studies on the vertebrate liver have been reported on mammals, avians, reptiles, amphibians, teleosts and cyclostomes, there are no studies on elasmobranchii liver except one by T. Ito etal. (1962) who studied it on light microscopic level. The purpose of the present study was to as certain the ultrastructural details and cytochemical characteristics of normal elasmobranchii liver and was to compare with the other higher vertebrate ones.Seventeen Scyliorhinus torazame, one kind of elasmobranchii, were obtained from the fish stock of the Ueno Zoo aquarium, Ueno, Tokyo. The sharks weighing about 300-600g were anesthetized with MS-222 (Sigma), and the livers were fixed by perfusion fixation via the portal vein according to the procedure of Y. Saito et al. (1980) for 10 min. Then the liver tissues were immersed in the same fixative for 2 hours and postfixed with 1% OsO4-solution in 0.1 Mc acodylate buffer for one hour. In order to make sure a phagocytic activity of Kupffer cells, latex particles (0.8 μm in diameter, 0.05mg/100 g b.w.) were injected through the portal vein for one min before fixation. For preservation of lipid droplets in the cytoplasm, a series of these procedure were performed under ice cold temperature until the end of dehydration.
Ultrastructure of vacuolated cells in the liver of rock sole and winter flounder living in contaminated environments
Authors: Stehr Carla 
Published: June 2020

Focal and diffuse areas of nonneoplastic vacuolated cells in the liver have been observed with light microscopy in up to 12% of the demersal rock sole (Lepidopsetta bilineata) inhabiting Eagle Harbor, which is a contaminated bay in Puget Sound. A similar type of liver vacuolation has also been observed at higher prevalences in winter flounder (Pseudopleuronectes americanus) inhabiting contaminated areas of Boston Harbor. This paper compares the ultrastructure of vacuolated liver lesions in feral rock sole with that of winter flounder from contaminated areas of Puget Sound and Boston Harbor, respectively.Rock sole from Eagle Harbor, Puget Sound, and winter flounder from Boston Harbor, were collected by bottom trawl from NOAA research vessels. Fish were killed and immediately necropsied. Adjacent pieces of tissue were collected for light and electron microscopy from grossly visible liver lesions or from the center of the liver. Samples collected for histology were fixed in Dietrich's solution, embedded in paraffin and stained with H&E.
Fine structure of dendritic cells in the epithelial cell layer of the ox tongue
Authors: Kobayashi Kan 
Published: June 2020

It is known that some kinds of dendritic cells are distributed in the epithelial cell layer of mucous membrane consisting of stratified squamous epithelium. In the process of exfoliation of the epithelial layer from the underlying connective tissue, dendritic cell bodies exposed on the ruptured surface of the epithelium were detected by scanning electron microscopy. These cells were also observed by light microscopy as well as by transmission electron microscopy.Dorsal mucous membrane of the ox tongue was fixed in Karnovsky's fixative or in 10% formalin. For scanning electron microscopy samples were immersed in 3N-HCl solution for 2-3 weeks at room temperature. The epithelial cell layer was removed from the underlying connective tissue layer1). They were postfixed in tannic acid and then 1% OsO4 for 1 hr. After dehydration in an ethanol series, the specimens were dried by passing through t-butylalcohol, coated with platinum-palladium and observed under an S-800 scanning electron microscope. For transmission electron microscopy, small pieces of the fixed tissue were post-fixed in 1% OsO4 for 1.5 hr and then embedded in Araldite-Epon.
Organization of the thyroglobulin polysome, studied in Endoplasmic Reticulum surface views of rough endoplasmic reticulum in cultured rat thyroid cells
Authors: Kent Christensen A. , Coon Hayden G. 
Published: June 2020

Thyroglobulin is synthesized in the thyroid gland and is subsequently degraded to provide thyroid hormones. Rat thyroglobulin is made up of two identical 330 kD subunits, and the mRNA for each subunit contains about 8,500 nucleotides. Since polysomes have approximately one ribosome for each 90-100 nucleotides of mRNA, a polysome of about 85-95 ribosomes would be expected for thyroglobulin. We have been interested in how this very large polysomes is organized on the membranes of the rough endoplasmic reticulum (RER).It is well known that bound polysomes assume characteristic shapes on the surface of the RER, resembling beads on a string arranged in circles, spirals, loops, hairpins or other forms. These polysomal shapes can be observed in conventional electron micrographs when the membranes of the RER are seen in surface or en face view, rather than in the usual cross section. Clearcut surface views are infrequent, but the likelihood of seeing them is greatly improved when flattened cells in culture are sectioned in the plane of the cell, since the RER in a flattened cell tends to be oriented in that plane.
The study of fine structure of wood of dove tree (davidia involucrata baill.) by SEM
Authors: Fangim Dai , Saoxin Zong , Dalin Dai , Jie Pan , Changhen Liang 
Published: June 2020

The dove tree is a beautiful, ornamental tree which is endemic to western China mainly, both in Sichuan and Guizhou Provunces. The fine structure of its wood has not been studied under SEM, even under LM. Since this tree is a rare species and is suffering from the danger of extinguishment on the earth, which has been protected by RAW, we trace it into consideration and try to provide some information for further exploiting and utilizing it. The method used in this study and the results obtained are stated as follows.The wood sample was furnished by Provincial Institute of Forestry Science, Sichuan, China. It was collected from Mongjing, Guizhou. The sample is cut with a single edge knife into a small cubic block which is mounted on metal stubs using double-sided tape, coated with a mixture of gold-palladium in a JFC-1100 sputter, and observed at 25 W, H-600 I analysis electron microscope with a H-6010A attachment.
Qualitative study on “hydropic degeneration” of The hepatocytes in viral hepatitis
Authors: Meizhao Le , Ming Ye , Xiaoming Song , Jiazhang Xu 
Published: June 2020

“Hydropic degeneration” of the hepatocytes are often found in biopsy of the liver of some kinds of viral hepatitis. Light microscopic observation, compareted with the normal hepatocytes, they are enlarged, sometimes to a marked degree when the term “balloning” degeneration is used. Their cytoplasm rarefied, and show some clearness in the peripheral cytoplasm, so, it causes a hydropic appearance, the cytoplasm around the nuclei is granulated. Up to the present, many studies belive that main ultrastructural chenges of hydropic degeneration of the hepatocytes are results of the RER cristae dilatation with degranulation and disappearance of glycogen granules.The specimens of this study are fixed with the mixed fluid of the osmium acidpotassium of ferricyanide, Epon-812 embed. We have observed 21 cases of biopsy specimens with chronic severe hepatitis and severe chronic active hepatitis, and found that the clear fields in the cytoplasm actually are a accumulating place of massive glycogen. The granules around the nuclei are converging mitochondria, endoplasm reticulum and other organelles.
Unusually large magnetite (Fe3O4) crystals inside a magnetotactic bacterium
Authors: Farina Marcos , Lins de Barros Henrique G.P. , Esquivel Darci M.S. 
Published: June 2020

Magnetite crystals inside magnetotactic microorganisms have been shown to cover a wide range of dimensions and shapes. However in almost all cases reported until now, crystals width and length remain under the magnetite monodomain dimensions when using Butler and Banerjee theoretical curves. We report here one type of magnetotactic bacterium which produces very large magnetite crystals as compared with those described in the literature. In a previous communication we had notified this fact, but without detail.Samples were collected from brakish water from ITAIPU lagoon near Rio de Janeiro (24° Southern hemisphere). In the same sample it was possible to find different magnetotactic microorganisms. After standard isolation treatments we obtained different groups of crystals identifyed as magnetite (Fe3O4) by electron diffraction.
Morphological changes of Helicobacter pylori caused in vitro by cytoprotective anti-ulcer drug, Sofalcone
Authors: Kondo Isamu , Yamaguchi Masashl 
Published: June 2020

Since Helicobacter pylori has recently been regarded as a possible causative agent of a chronic gastritis and a peptic ulcer disease, the susceptibilities of this organism to anti-ulcer agents or antibiotics have attracted much interest of not only clinical docters but also medicobiologists.We have reported that Sofalcone, a cytoprotective anti-ulcer drug, has anti-bacterial and bactericidal activity as well as TDS (tripotassium dicitrats bithmuthate) and Clarithromycin (a derivative of erythromycin), but the other anti-ulcer drugs Including anti-acid or H2 receptor antagonists such as cimetidine could not show such bacterial activity as those shown by the sofalcone (SFC), TDB, and clarithromycin (CLM). It was also found that therewere distinct differences between the morphological damage of H. pylori caused by SFC and those caused by TDB and CLM.
Structures of cotton motes and mote fibers
Authors: Goynes W. R. , Ingber B. F. , Thibodeaux D. P. 
Published: June 2020

A mote is a seedlike structure that is derived from an ovule, but that does not develop into a mature seed. In cotton, motes vary in size from tiny structures having no fibers, to those that appear to be full-sized seed with fibers approximately the length of fully-developed fibers. The size of the mote depends on the stage at which its development was arrested. In the cotton industry these undeveloped seed, as well as the quality of fibers produced by them, are of commercial importance. Results presented here are from an exploratory study to show differences between structures of normal seed and fibers, and motes and mote fibers.Cotton seed develop within a closed boll that is separated into compartments or locules. Embryo development is normally completed within the seed in approximately 35 days. Fiber growth initiates on the seedcoat surface as cells elongate to become thin-walled tubes until approximately 18-20 days postanthesis when the main body of the fiber, the secondary wall, begins to be laid down.
Freeze-substituted fungal cells of Nectria haematococca: A comparison of the macroconidial walls of the adhesion-competent wild type with an adhesion-reduced mutant
Authors: Caesar-Ton That Thecan , Epstein Lynn 
Published: June 2020

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.