bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation of Intracellular Calcium Measurements Using X-Ray Microanalysis and Fluorescence Microscopy Techniques
Authors: Hagler H.K. 
Published: June 2020

It is my thought that calcium plays a major role in the development of irreversible cellular injury in the myocardium.There are two basic forms of calcium within the cell, the active, ionized calcium and the inactive form which may be bound to cell proteins or held in storage sites within the cells.The use of energy dispersive x-ray microanalysis in an analytical electron microscope permits the localization and measurement of the total elemental content of subcellular regions of cells. These measurements generally require that the cells be cryofixed , cryosectioned, cryotransfered and freeze dried in the electron microscope. The Hall method of continuum normalization is then used to convert the x-ray intensity measurements into dry weight concentrations.Because the cells have to be cryofixed, it is not possible to follow the development of elemental changes within a single cell over time, thus many cells have to be frozen at different time intervals to measure time dependent changes of irreversible injury and cell death. Thus, selected time points are identified and sampled for x-ray microanalysis.
Electron Microscopic observations of the aquatic caterpillar Acentropus niveus (Olivier)
Authors: Green I.S. , Smith D. L , Boylen C. W. 
Published: June 2020

Acentropus niveus is of special interest because it is one of a few species
of Lepidoptera that is truly aquatic and because it feeds on Eurasian (Myriophyllum spicatum). M. spicatmn, an introduced aquatic plant, is considered a major nuisance in many lakes in North America and Europe. It has been speculated that A. niveus may act as a biological control agent (1). Although a number of ecological studies of this caterpillar have been done, none has included electron microscopy.A. niveus larvae were collected from recently established milfoil beds in Lake George, New York. Individuals were fixed either overnight in 2% glutaraldehyde in 0.1M Na-cacodylate buffer, pH 7.2, or for several months in 70% ethyl alcohol. Glutaraldehyde fixation was followed by rinsing three times in 0,1M Na-cacodylate buffer for 15 minutes each, dehydration in a graded ethanol series, critical-point drying, and sputter-coating with gold. The ethanol-fixed larvae were dehydrated, critical-point dried, and gold coated. All were examined with an Etec Autoscan SEM operated at 20 KV.
Ultrastructure of the digestive tube of the black mollie
Authors: Caceci Thomas , Hrubec Terry C. 
Published: June 2020

The black mollie (Poecilia spp.) is a teleost fish found in Central American estuaries, and taxonomically related to the carps and goldfish. The common strains sold in pet stores are hybrids of P. mexicana and P. sphenops. The ultrastructure of its digestivetract has not previously been described.As with other Cyprinidontiforms, the gut is anatomically simple, consisting of a relatively undifferentiated tube from esophagus to anus. The tube is lined with a simple columnar epithelium and has an external wall composed of two layers of smooth muscle. A serosal investment covers this external muscular tunic. Six intestines were examined by scanning and transmission EM. The fish were anesthetized by chilling and opened on the left side. The gut was removed, unwound, and fixed intact in a 3.0% glutar-aldehyde/ 2.0% formaldehyde/ 2.5% picric acid mixture at RT and buffered with cacodylate at pH 7.4. After primary fixation, each intestine was arbitrarily divided into a cranial, middle, and caudal segment, and four specimens were post-fixed in osmium tetroxide, dehydrated, and embedded for TEM examination. Two specimens for SEM examination were washed, treated with 1.0% tannic acid, then post-fixed in osmium tetroxide, dehydrated, and critical-point dried through CO2.
Ultrastructure of lymphatic endothelium
Authors: Singh A. , Ezeasor D.N. , Sidhu N.K. 
Published: June 2020

Recently, the lymphatics in the caprine hemal nodes have been described. The present study describes some ultrastructural features of the endothelium in the lymphatics of the goat hemal nodes.Hemal nodes located along the aorta, were collected from 15 clinically healthy, adult, West African dwarf goats. The tissues were fixed by either immersion or perfusion methods. For immersion fixation, the nodes were excised, and immersed temporarily in cold 2.5% glutaraldehyde in 0. IM cacodylate buffer, pH 7.3. After 5 min, the nodes were diced into 1-2 mm cubes and further fixed for 2 h in the same fixative. The par-aortic nodes were fixed by vascular perfusion. The two batches of tissues were post-fixed in 2% osmium tetroxide in cacodylate buffer, and further processing was done by conventional methods for transmission electron microscopy. The thin sections were examined and photographed in a
Hitachi H-7000 electron microscope.The lymphatic wall comprised a continuous layer of fenestrated endothelial cells. The nuclei were oval and contained
heterochromatin. The cytoplasm exhibited fenestrations that were closed by a membrane, and vesicular compartments bound on luminal and/or abluminal aspects by fenestrated membranes(Fig. 1). occasionally lymphocytes(Fig. 2) or erthyrocytes, most probably intransit, occupied these compartments. In material fixed by immersion, most of the vesicles contained flocculent material similar to that contained in the lumen(Fig. 3).
The structure of patch-clamped membranes in high voltage Electron Microscopy
Authors: Ruknudin A. , Song M.J. , Auerbach A. , Sachs F. 
Published: June 2020

The study of single ion channel kinetics in cell electrophysiology has been made possible by the introduction of patch-clamp techniques. Recordings can be made from a patch of membrane either attached to the cell or excised into controlled solutions. Though this technique has been widely used for more than a decade, the structure of the membrane patch and its associated cytoplasmic elements are not known except for recent work done in this laboratory . We have improved this technique to visualize membrane patches using high voltage electron microscope and also identified one class of channels in the patch by immunocytochemistry.The procedure for preserving biological structure in a glass patch pipette is basically same as described earlier as “dry mounting technique” . Briefly, after making a patch, the pipette is removed from the bath and the tip is freeze-fixed in liquid propane. A slight negative pressure is applied to the pipette while freeze-fixing in order to stretch the shape of the patch. Once fixed, the tip is not exposed to temperatures higher than-126° C. A 0.5 cm bit of the pipette tip is broken off, stored in IN2, and then freeze dried between -126° to -80° C under high vaccum (10-6Torr).
Ultrastructural evaluation of hippocampus in rhesus monkeys after intravenous delta-9-tetrahydrocannabinol (THC): 90-day study
Authors: Andrews A.M. , Scallet A.C. , Uemura E. , Ali S.F. , Bailey J.W. , Paule M.G. , Brown R.M. , Slikker Wm. 
Published: June 2020

A previous study of two rhesus monkeys exposed either to intravenous delta-9- tetrahydrocannabinol (THC) or marijuana smoke via inhalation presented ultra- structural evidence of increased synaptic width (Harper et al., 1977). Studies with rats have shown decreased synaptic density and decreased dendritic branching in the hippocampus following withdrawal after 90 days of administration of THC, the major psychoactive ingredient of marijuana (Scallet et al., 1987).Our preliminary study in monkeys was to assess the risk, of potential neuropatho- logical alterations produced by intravenous THC for 90 days in rhesus monkeys to prepare for a longer term study of inhalation exposure.Juvenile male rhesus monkeys, 2-3 years of age and weighing 2.5-3.5 kg were used. 1.0 or 0.1 mg/kg THC or vehicle (4-5 animals per group) were administered intravenously once daily for 90 days. The monkeys were sacrificed the day after completion of treatment. Specimens from 14 rhesus monkeys, perfused with mixed aldehydes as described by Harper et al., 1977, were taken for transmission electron microscopy (TEM) of the mid-body of the hippocampus (Demeter et al., 1985) as well as certain other brain regions. Samples were post-fixed in 4% glutaraldehyde, followed by osmium tetroxide and embedded in Epon-Araldite resin, lμ sections were stained with methylene blue and azure II and examined with the light microscope to select the CA3 region for thin sectioning. The CA3 region was identified by reference to the blades of the dentate gyrus and the presence of mossy fibers. Thin sections (l00nm) were stained with uranyl acetate and lead citrate then examined at 60kV in a Philips 201 TEM.
Spindle shaped bodies in foveolar cones of the baboon retina
Authors: Krebs W. , Krebs I. 
Published: June 2020

Various inclusion bodies occur in vertebrate retinal photoreceptor cells. Most of them are membrane bound and associated with phagocytosis or they are age related residual bodies. We found an additional inclusion body in foveal cone cells of the baboon (Papio anubis) retina.The eyes of a 15 year old baboon were fixed by immersion in cacodylate buffered glutaraldehyde (2%)/formaldehyde (2%) as described in detail elsewhere . Pieces of retina from various locations, including the fovea, were embedded in epoxy resin such that radial or tangential sections could be cut.Spindle shaped inclusion bodies were found in the cytoplasm of only foveal cones. They were abundant in the inner segments, close to the external limiting membrane (Fig. 1). But they also occurred in the outer fibers, the perikarya, and the inner fibers (Henle’s fibers) of the cone cells. The bodies were between 0.5 and 2 μm long. Their central diameter was 0.2 to 0. 3 μm. They always were oriented parallel to the long axis of the cone cells. In longitudinal
sections (Figs. 2,3) they seemed to have a fibrous skeleton that, in cross sections, turned out to consist of plate-like (Fig.4) and tubular profiles (Fig. 5).
Scanning Electron Microscopic study on chicken pituitary cells
Authors: Tai S. , Velasquez C. 
Published: June 2020

The cytology and histology of the vertebrate pituitary glands have been studied extensively under light microscopy and transmission electron microscopy. These informations form the basis for the generally accepted concept that the specific cell types synthesize, store and release their particular hormones. These hormonal products are stored in membrane-bound secretion granules in the cytoplasm.Tanaka developed the 0 smium-DMS 0-0 smium (ODO) method which can remove the excess cytoplasmic matrices from the frozen-fractured surface of pre-fixed cells and revealed intracellular structures of many kind s of cells from liver, retina, etc. In this work, we have used the ODO method and Field Emission SEM to obtain 3-dimensional images of the fine structure of pituitary cells, as a new approach to have a better idea about the intracellular organization of the hormone secretory cells .Chicken pituitary glands were fixed in 0.5% glutaraldehyde in 0.2M phosphate buffer(pH=7.2) for ½ h; rinsed with the same buffer; postfixed in 0.5% OsO4 for another ½h. After been rinsed throughly, specimens were passed through 25% and 50% dimethyl sulfoxide(DMSO) solution for 30 minutes each.
Localization of actin in boar spermatozoa using myosin S1-colloidal gold
Authors: Bozzola J. J. , Peterson R. N. , Hunt W. P. 
Published: June 2020

Actin has been reported to be present in the sperm cells of a number of mammalian species. The location and form of actin (monomeric or polymeric) is variable from species to species with monomeric or G-actin being the predominant type. The cytoskeleton is thought to be involved in maintaining the structural/chemical specialization of the plasma and acrosomal membranes of mammalian sperm cells, since actin has been localized in various regions. Cytochalasin D, a specific inhibitor of actin polymerization, inhibits fertilization of hamster eggs, indicating that F-actin may play an important role in the fertilization process. Since the exact form and location of actin has not been resolved, we used the myosin SI subfragment coupled to colloidal gold to localize F-actin in boar caput and cauda epididymal as well as ejaculated sperm cells.The sperm cells were washed in an F-actin stabilizing buffer (pH 7.0) consisting of 5 mM Na2HP04, 5 mM NaH2P04, 135 mM NaCl, 5 mM MgCl2, 2 mM EGTA, 0.005% PMSF, 0.005% PTAME, and 1 mg/ml soybean trypsin inhibitor.
Enhancement of the fine structure of Pneumocystis carinii using potassium ferrocyanide and tannic acid
Authors: Goheen M.P. , Blumershine P. , Hull M.T. , Bartlett M.S. , Smith J.W. 
Published: June 2020

Pneumocystis carinii (PC) is an obligate parasite found in the lungs of many vertebrates including man. A recent upsurge of interest in this organism is due to its role in producing severe pneumonia in over two thirds of individuals with acquired immunodeficiency syndrome (AIDS). Many studies have been published of the ultra- structure of PC in steroid treated rats or immunocompromised patients. Several laboratories have reported growing PC in culture, but few ultrastructural studies have resulted. Additionally, PC from culture or vertebrates has been difficult to fix in a fashion which would preserve the fine structural detail. This study reports that post-fixation with tannic acid-osmium and ferrocyanide-osmium mixtures greatly improves the ultrastructural morphology of PC from culture.Human embryonic lung fibroblasts were cultured in minimal essential medium with 10% fetal calf serum. The cultures were inoculated with viable trophozoites obtained from steroid treated rat lung and incubated in 5% O2 10% CO2, balance N2 at 35°C for seven days. At this time three aliquots of tissue culture fluid were centrifuged to obtain pellets of PC. The supernatants were decanted and replaced with Karnovsky's fixative, and the pellets allowed to fix for two hours at 20°C. Following a rinse in cacodylate buffer two of the specimens were post-fixed in 1% buffered osmium, and the third specimen was immersed in a mixture of 1.5% OSO4 and 2.5%
Freeze substitution fixation of fungal reproductive structures and spores
Authors: Mims C. W. , Richardson E. A. 
Published: June 2020

The advantages of freeze substitution fixation over conventional chemical fixation for preservation of ultrastructural details in fungi have been discussed by various authors. As most ascomycetes, basidiomycetes and deuteromycetes do not fix well using conventional chemical fixation protocols, freeze substitution has attracted the attention of many individuals interested in fungal ultrastructure. Thus far most workers using this technique on fungi have concentrated on thin walled somatic hyphae. However, in our laboratory we have experimented with the use of freeze substitution on a variety of fungal reproductive structures and spores with promising results.Here we present data on freeze substituted samples of sporangia of the zygomyceteUmbellopsis vinacea, basidia ofExobasidium camelliaevar.gracilis, developing teliospores of the smutSporisorium sorghi, germinating teliospores of the rust Gymnosporangium clavipes, germinating conidia of the deuteromyceteCercosporidium personatum,and developing ascospores ofAscodesmis nigricans.Spores ofG. clavipesandC. personatumwere deposited on moist pieces of sterile dialysis membrane where they hydrated and germinated. Asci ofA. nigricansdeveloped on pieces of dialysis membrane lying on nutrient agar plates.U. vinaceawas cultured on small pieces of agar-coated wire. In the plant pathogensE. camelliaevar.gracilisandS. sorghi, a razor blade was used to remove smal1 pieces of infected host issue. All samples were plunged directly into liquid propane and processed for study according to Hoch.l Samples on dialysis membrane were flat embedded. Serial thin sections were cut using a diamond knife, collected on slot grids, and allowed to dry down onto Formvar coated aluminum racks. Sections were post stained with uranyl acetate and lead citrate.
Preservation of embryo ultrastructure by high-pressure freezing and freeze substitution
Authors: McDonald Kent , Morphew Mary K. 
Published: June 2020

Ultrarapid freezing is a well-established technique for the optimal preservation of cellular ultrastructure. The size of the sample which can be well-frozen is determined by the physics of heat transfer and under normal atmospheric pressure the upper size limit of material without cryoprotectant is about 40 um. However, if one can freeze the sample under high pressure (optimum about 2100 bars) then the maximum sample diameter can be around 0.6 mm. Moor and Riehle provided the theoretical basis and design for the high pressure freezer which has evolved into the commercial instrument (the Balzers HPM 010) now available from Balzers Corporation, Hudson, NH. We have used the Balzers HPM 010 plus the specimen holders designed by Craig et al. for the results presented here.The materials selected for this study include the early embryonic stages of Drosophila melanogaster, Strongylocentrotus purpuratus, Caenorhabditis elegans and oocytes of Xenopus laevis, Samples were mixed with a cryoprotectant (either a yeast paste made up with 10% methanol or 1-hexadecane) and loaded into the specimen holders, making sure that no air spaces remained. The time between loading and freezing was typically less than a minute to minimize prefreezing damage. Tests with S. purpuratus showed that brief exposure to the cryoprotectants had little or no effect on embryo viability.
Localization of acid phosphatase in rice calli
Authors: Huang Y. F. , Chen Y. R. 
Published: June 2020

Acid phosphatase is an important hydrolytic enzyme and widely distributed in plants. The role of acid phosphatase in plant tissues has been suggested involving in mobilization of nutrient reserves, sugar transport, differentiation of plastid, cell autolysis and senescence. In culture, the differentiating calli show the changes in isozyme patterns and activities, and anatomical localization. In this study, subcellular localization of acid phosphatase in regenerating callis is emphasized.Sterized rice seeds(Oryza sativaTainong 67) were grown on modified MS medium containing 2 ppm 2,4-D. After 2 weeks, calli 2 to 3 mm in size were transfered on differentiation medium containing 1 ppm NAA and 2 ppm kinetin. Different stages of calli were collected and cut into thin slice with razor blade. Slices were fixed in 2.5% glutaraldehyde in 0.1M phosphate buffer(pH 7.0) for 2h and then washed, overnight . Specimens were incubated in Gomori solution containing 3mM p- nitrophenyl phosphate as substrate at 37°C for 90 min, postfixed with 1% OsO4for lh, dehydrated in ethanol series and embedded in Spurr's resin. Control experiments were done as follows: l), incubation medium without substrate; 2),incubation medium without lead nitrate; 3), incubation medium containing 0.01% NaF. Sections were doubly stained with uranyl acetate and lead citrate, and finally observed under Hitachi H-600 at 75 KV.
Electron Microscopic study of two strains of bovine viral diarrhea virus (BVDV)
Authors: Alain R. , Cardin S. , Berthiaume L. , Lecomte J. 
Published: June 2020

Bovine viral diarrhea virus (BVDV) is an economically important pathogen of cattle throughout the world, causing a wide range of clinical syndromes. Virion is spherical, 40-70 nm in diameter, with an envelope tightly applied to a spherical nucleocapsid 25-35 nm in diameter with icosahedral symmetry (figure 1 and 2) (Matthews, 1979) . It is presently included in the Togavlridae family, genus Pneumovirus but Collett et al. (1988) have proposed to group this genus in the Flaviviridae family. In the present study, two strains of BVDV were compared by electron microcospy ultrathin sections: one cytopathogenic, NADL strain, and the other non-cytopathogenic, NY-1 strain. These were Inoculated on Madney-Darby Bovine Kidney (MDBK) cells to a multiplicity of infection (m.o.i) between 3,0 and 5,0. Control and virus infected cells were fixed with glutaraldehyde (2,5% in cacodylate buffer) at 24 , 48, 72 and 96 h following incubation at 37°C. Cells were postfixed with osmium tetroxide and embedded in Vestopal.The NADL-CP strain infected cells showed vacuolization of the endoplasmic reticulum, ribosomal activity in the cytoplasm and appearance of virus particles 48h after infection (figure 3). At 72h, an expensive vacuolization was apparent (figure 4). Maximum viral production was seen 96 h after infection (figure 5). From 24 to 72 h post infection, the NY-l-NCP strain of BVD infected cells showed normal vacuolization like in control cells. They produced weak vacuolization with few particles, not apparent before 96h after infection (figure 6). Viral particles of 45-50 nm in endoplasmic reticulum vacuoles were in general homogenous in size while those in smooth membranes, probably of cellular origin, heterogenous in size.
Immunogold labeling of phycobilisomes in a cyanobacterium
Authors: Zianni M. R. 
Published: June 2020

Phycobilisomes are pigment-protein complexes that act as the major light- harvesting antenna, in addition to chlorophyll, for photosynthesis in red algae and Cyanobacteria.In vivo, phycobilisomes transfer their energy mainly to the photosystem II reaction center to which they are assumed to be attached. This assumption will be tested by the use of gold labeling of antibodies raised against photosystem II reaction center components to localize the reaction centers and to compare the location of the antibodies with that of the phycobili- somes. In Cyanobacteria phycobi1isomes are difficult to fix particularly under conditions required for immunocytochemistry. Here, two methods for efficient fixation of phycobi1isomes are described, together with immunocytochemical results to confirm the identity of the phycobilisomes.For phycobilisome detection,Synechocvstissp. PCC 6803 cells were either freeze substituted or fixed in a high molarity buffer followed by cryomicrotomy. For freeze substitution the cells were collected, subjected to ultra-rapid freezing with a slammer device and a copper block at liquid helium temperature, placed in 5% acrolein in ethanol at -85°C for 4 days, and embedded in LR White. For cryo- sectioning the cells were fixed with 1% glutaraldehyde in 0.75M sodium potassium phosphate buffer, pH 7.4, for 2 h, enrobed in 10% gelatin, infused with 1.6M sucrose in 0.1M sodium phosphate buffer,pH 7.2, for 3 h, and frozen in liquid freon. Cryosections were prepared with an RMC CR2000 cryoultramicrotomy unit on an MT-6000 ultramicrotome. In both procedures 0.05% Carnation nonfat dried milk in 0.1M sodium phosphate buffer was used to block nonspecific binding of the anti serum. Sections were treated with rod-phycocyanin (phycobilin protein) anti - serum followed by protein A conjugated to lOnm gold particles. Subsequently the plastic sections were stained with uranyl acetate and lead citrate. The cryosections were subsequently treated with 1% OSO4, 1% tannic acid, uranyl acetate, and alkaline bismuth, dehydrated in ethanol, and embedded in LR White. Sections were observed in a Philips EM201.