bluuebunny/crossref_metadata_2025 huggingface dataset:
Gingival epithelial overgrowth in Renal transplant
Authors: Gonzalez-Jaranay Maximino , Fernández-Segura Eduardo , Moreu Gerardo , Campos Antonio
Published: June 2020

In the past decade cyclosporine (CsA) has reached wide acceptance in therapy for patients undergoing organ transplant. CsA selectively inhibits T cell function while having a minimal effect on humoral immunity. As with drugs which modulate host responses, sequelae such as gingival overgrowth, are common. Different studies have emphasized the cell biology of fibroblast and immune system cells in gingival connective tissue, but few have approached the gingival epithelium with TEM and SEM. This latter procedure not only gives us pictures of the most supercial layer but also produces three-dimensional images of extensive areas of the gingival mocosa.

Specimens of overgrown and healthy tissue obtained during gingivectomy were fixed for TEM in 2.5% cacodylate buffered glutaraldehyde. Postfixation with 1% osmium tetroxide and embedding in Spurr's resin followed. Sections were contrasted with lead citrate and uranyl acetate and examined in a Zeiss EM10C. For SEM specimens after identical fixation, were dehydrated, critical-point dried. Gold sputtercoated and observed in a Philips SEM 505.
Electron Microscopic observation on the semen of HIV-positive men
Authors: Koehler James K. , Coombs Robert W. , Collier Ann C. , Krieger John N. , Corey Lawrence
Published: June 2020

Despite well-documented studies showing HIV transmission by and isolation from semen, relatively little information is available concerning the morphology and cellular characteristics of the semen of HIV positive individuals. We have there fore examined the semen of HIV infected patients with electron microscopy in order to determine cellular ultrastructure and possible sites of virus in this material. Patients were assayed for HIV in peripheral blood, and cell free plasma, as well as semen and CD-4-T-cells were counted. Ejaculates were obtained from 9 HIV positive individuals. Five had symptomatic HIV infections: three had AIDS and were on zidovudine therapy, two had ARC (AIDS Related Complex); four were asymptomatic. All were HIV culture positive from blood, and two were HIV culture positive from semen. Table 1 details the disease category and HIV assay data in these patients. Electron microscopy revealed that semen from the symptomatic AIDS group was infiltrated with macrophages and other white cells with extensive phagocytosis of sperm and other debris (Figure 1).
Ultrastructural characterization of basophils and mast cells derived from CD34+ human bone marrow progenitor cells
Authors: Goff J.P. , Kirshenbaum A. S. , Albert J. P. , Metcalfe D. D.
Published: June 2020

In the mouse, mast cell progenitor cells (Thyl +) have been shown to originate in the bone marrow. In humans, it has been suggested that mast cell progenitors also exist in the bone marrow, are derived from a common stem cell, and mature under cytokine influence in the tissue. Progenitor cells or CD34+ cells comprise approximately 1% of bone marrow mononuclear cells.

Previously we have shown that a heterogenous population of human bone marrow cells cultured over agarose surfaces in the presence of rhIL-3 gives rise to basophils and small numbers of mast cells. Cells were identified as basophils based on characteristic morphology, metachromatic staining with Wright-Giemsa and acid toluidine blue, surface IgE as determined by fluorescence and the presence of histamine by o-Phthaldialdehyde condensation. These cells did not stain for the mast cell specific neutral protease, tryptase. Cells identified as mast cells had IgE receptors, contained histamine and were chloroacetate esterase and human mast cell tryptase positive.
Ultrastructural morphology of neurosecretory neurons in the barnacle Balanus amphitrite
Authors: Tagliafierro Grazia , Crosa Cristiana , Canepa Marco , Zanin Tiziano
Published: June 2020

Barnacles are very specialized Crustacea, with strongly reduced head and abdomen. Their nervous system is rather simple: the brain or supra-oesophageal ganglion (SG) is a small bilobed structure and the toracic ganglia are fused into a single ventral mass, the suboesophageal ganglion (VG). Neurosecretion was shown in barnacle nervous system by histochemical methods and numerous putative hormonal substances were extracted and tested. Recently six different types of dense-core granules were visualized in the median ocellar nerve of Balanus hameri and serotonin and FMRF-amide like substances were immunocytochemically detected in the nervous system of Balanus amphitrite. The aim of the present work is to localize and characterize at ultrastructural level, neurosecretory neuron cell bodies in the VG of Balanus amphitrite.

Specimens of Balanus amphitrite were collected in the port of Genova. The central nervous system were Karnovsky fixed, osmium postfixed, ethanol dehydrated and Durcupan ACM embedded. Ultrathin sections were stained with uranyl acetate and lead citrate. Ultrastructural observations were made on a Philips M 202 and Zeiss 109 T electron microscopy.
Immunolocalization of individual filament-forming proteins in the cytoskeleton of Tetrahymena
Authors: Yi Hong , Williams Norman E. , Dress Virginia M. , Moore Kenneth C.
Published: June 2020

Four polypeptides (tetrins I-IV) have been isolated from the ciliated protozoan Tetrahvmena pyriformis. These polypeptides assemble in vitro into 3-4 nm filaments identical with those present in abundance in a cytoskeletal framework associated with the feeding organelle system (oral apparatus) of this cell type. The polypeptides ranging in molecular weights from 79-89 kDa are not similar to each other in either biochemical or immunological properties. In vivo, the filaments are organized into higher order structures described as cages, cables, and networks. The specific hypothesis arises that the alternate packing arrangements may correlate with different distributions of the individual tetrin polypeptides. We report the production of monoclonal antibodies for each tetrin polypeptide, and the determination of the location of each within the cell using confocal microscopy and immunogold-silver enhancement procedures in conjunction with transmission electron microscopy (TEM).

Cell samples for confocal microscopy were labelled according to conventional immunofluorescent procedures and examined with a Bio-Rad MRC-600 laser scanning confocal microscope.
Scanning Electron Microscopy of antennal sensilla of the Japanese tusser, Antheraea vamamai
Authors: Jian Hong , Cui Hu , Congyin Ye , Qikang Gao
Published: June 2020

Antennal surface structure of the Japanese tusser, Antheraea yamamai was observed by scanning electron microscope. The antennae of male and female were bipectinate with scape, pedicel and 33--37 flagellar segments. There were two pairs of equal long branch on eacli flagellar segment of male (Fig.1), but a pair of longer and a pair of shorter on female's (Fig.2).

Seven types of sensillum, namely sensillum trichodeum, sensillum cheaticum, sensillum coeloconicum, sensillum campaniformlum, sensillum styloconicum, Bohm's bristle and sensillum squamiformium wer found on the antenna both of male and female. The sensillum trichodeum could be subdivided into long and short according to the shape and surface substructure. The long sensillum trichodeum had a diameter of 4.8μm at its base. It was reratively stright and slightly curved at the tip (Fig.3). The short sensillum trichodeum was 2.5--3.6 μm in diameter at the base. It was shorter, strongly bend down near its base and run parallel with the surface of the antenna (Fig.4). The surface of long and short sensilla trichodea were covered with annular ridges (Fig.5).
Ultrastructure of microfilarial sheath and its comparison with egg shell
Authors: Howe Lye , Chun Josephine , Zaman Viqar
Published: June 2020

In this study the ultrastructure of the uterus of Brugia malayi and its contents were studied especially to reveal the relationship between the sheath of the microfilaria and the egg shell, as it is claimed that the egg shell ultimately forms the microfilairal sheath (Rogers et al, 1976).

The cross section of the worm revealed a distinct cuticle, musculature, a single patent fut and paired uteri. The uterine contents were filled with eggs at various stages of development. Inside each egg were embryonic cells which corresponded to the so-called “nuclei” of microfilaria which are seen in the light microscope. The egg shell was discernable as a membrane with minute electron-dense projections on its surface. At higher magnification the egg shell was seen to consist of two structures - a homogenous basement membrane and electron dense projections which rested on it. These projections were found all around the egg shell and consisted of a broad base and a pointed anterior end.
Impact of social environment on the fat body development of worker ants
Authors: Rosell Rosemarie , Wheeler Diana E.
Published: June 2020

In ants, colonies are composed of one or a few queens and many female, but usually sterile, workers. The reproductive capability of workers is inhibited by the queen. In the ant genus,Camponotus, workers can develop the capacity to lay eggs in the absence of the queen. Large workers, termed soldiers, show the greatest tendency to deposit yolk and lay eggs. The insect fat body is the site of synthesis of proteins used in reproduction, most notably vitellogenin. In this study, we compare the development of fat body in soldiers that have been maintained in the presence of the queen (Q+) with those that have been removed from her inhibitory influence (Q-).

Just before the adult molt, pupae were removed fromC. festinatusparent colonies maintained in the laboratory. After emergence, individuals were divided into two groups. Q- individuals were maintained in petri dishes in groups of 25-30 in the absence of the queen. Q+ workers were marked and immediately returned to the parent colony.
The distribution and density of ciliary tufts on the siphons of Anodonta cygnea (Mollusca: Bivalvia)
Authors: Wu Wen-lung
Published: June 2020

The mantle of bivalves has come entirely to enclose the laterally compressed body and the mantle margin has assumed a variety of functions, one of the pricipal ones being sensory. Ciliary tufts, which are probably sensory, have been reported from the mantle and siphons of several bivalves1∽4. Certain regions of the mantle margin are likely to be more or less, sensitive to certain stimuli than others. The inhalant siphon is likely to be particularly sensitive to both chemical and mechanical stimuli, whereas the exhalant siphon will be less sensitive to both. The distribution and density of putative sensory receptors on the in-and ex-halant siphon is compared in this paper.

The excised siphons were fixed in glutaraldehyde and osmium tetroxide, the whole procedure of SEM study is recorded in Wu's thesis.

Type II cilia cover the tips of tentacles, 6.13um. Type IV and type V cilia are found on the surface of tentacles. Type IV cilia are occasionally present at the tips of tentacles, 8 um long. They are the commonest type on the surface of tentacles. Type VI cilia occor in the internal surface of the inhalant siphon, but are not found on the surface of tentacles, 6.7-10um long.
Scanning Electron Microscopic study of bats hair as an aid of species identification
Authors: El Gohary M. , Banerjee R.K. , Nader I.A.
Published: June 2020

Cuticular scales patterns of hair shafts have been studied in order to show variations associated with mammalian species bearing hair. Results of microscopical studies of mid-dorsal hair shafts of certain Philippine bats showed that the type of pigmentation and the cuticular scales did not vary within the genera but did within the families. It is clearly demonstrated that the mammals showed variant patterns of cuticle structure of hair shafts by SEM and could be used for identifying different mammals.

Mid-dorsal hair shafts of 15 species of Saudi Arabian bats (O.Chiroptera) were ultrasonically cleaned, dehydrated, coated with gold/palladium and photographed by JSM-35. The hair cuticle of 15 species of different genera and families of bats were investigated (Rhinopoma microphyllum, Rousettus aegyptiacus, Taphozous perforatus, Tagphozous
A TEM study on the uptake of AMI 25 by sinusoidal liver cells
Authors: Wisse E. , Doucet D. , Van Bossuyt H.
Published: June 2020

Earlier studies have indicated that the liver plays a major role in the clearance of Ami 25 colloidal particles, consisting of dextran-stabilized superparamagnetic ferric oxyhydroxide citrate, used for increasing the contrast during NMR imaging of the liver. The uptake of these particles by different cell types in the rat liver was studied, at time intervals ranging from 3 minutes to 1 month.

Two different dose levels were used, i.e. a single, low dose of 1,1 mg Fe/kg, comparable to the dose given to patients, and a single, tenfold dose of 11,3 mg Fe/kg. Controls received saline injections. I.v. injections were given to young adult male Wistar rats. After perfusion fixation of the liver with isotonic, buffered, 1.5% glutaraldehyde, at 10 - 12 cm H2O pressure during 7 min at 20 °C and a flow rate of 7ml/min, tissue blocks were postfixed in 1% osmium, dehydrated in ethanol, and embedded in Epon. Ultrathin sections were observed in the transmission electron microscope. In addition, Fe determinations were performed on total liver and on isolated sinusoidal cells.
Gold labeling of teichoic acid on adjacent surfaces of staphylococcus aureus
Authors: Hukee Margaret
Published: June 2020

Gold labeling of two antigens (double labeling) is often done on two section surfaces separated by section thickness. Whether labeling is done on both sides of the same section or on two parallel surfaces separated by section thickness (PSSST), comparable results are dependent on an equal number of epitopes being exposed at each surface. We propose a method to study protein labeling within the same field of proteins, by examining two directly adjacent surfaces that were split during sectioning. The number of labeling sites on adjacent surfaces (AS) were compared to sites on PSSST surfaces in individual bacteria.

Since each bacteria needed to be recognizable in all three section surfaces, one-hole grids were used for labeling. One-hole grids require a supporting membrane and excessive handling during labeling often ruptures the membrane. To minimize handling, a labeling chamber was designed that is inexpensive, disposable, minimizes contamination, and uses a minimal amount of solution.
Transmission Electron Microscopy of microorganism fine structure in dry state
Authors: Gerasimov V. , Volkov V.
Published: June 2020

Routine methods for preparing biological specimens for electron microscopy are based on the usage of water solutions of fixatives. The Investigation of microorganisms in anabiosis shows that this results in rehydration of specimens and disturbance of the initial structure. In the paper it is proposed to use the waterless fixatives or the fixatives containing little water in order to analyze the structure of lyophilized microorganisms.

Bacteria and yeasts in dry anabiosis were fixed in dehydrated OsO4 vapor. or in 1-2 % OsO4 solution on the basis of 97-95 % water acetone at room temperature for 24-72 h. After fixation, dehydrated microorganisms were placed on the formvar film by suspending cells in 1-4 % formvar solution on the basis of dichlorethan followed by suspension lyophilization on a glass up to film formation.
Exposure of protein VP7 on the surface of bluetongue virus
Authors: Hyatt A.D.
Published: June 2020

Bluetongue virus (BTV) is the type species os the genus orbivirus in the family Reoviridae. The virus has a fibrillar outer coat containing two major structural proteins VP2 and VP5 which surround an icosahedral core. The core contains two major proteins VP3 and VP7 and three minor proteins VP1, VP4 and VP6. Recent evidence has indicated that the core comprises a neucleoprotein center which is surrounded by two protein layers; VP7, a major constituent of capsomeres comprises the outer and VP3 the inner layer of the core . Antibodies to VP7 are currently used in enzyme-linked immunosorbant assays and immuno-electron microscopical (JEM) tests for the detection of BTV. The tests involve the antibody recognition of VP7 on virus particles. In an attempt to understand how complete viruses can interact with antibodies to VP7 various antibody types and methodologies were utilized to determine the physical accessibility of the core to the external environment.
TEM processing procedure for a bacillus organism grown on solid media
Authors: Payne Jane , Coudron Philip
Published: June 2020

This transmission electron microscopy (TEM) procedure was designed to examine a gram positive spore-forming bacillus in colony on various solid agar media with minimal artifact. Cellular morphology and organization of colonies embedded in Poly/Bed 812 resin (P/B) were studied. It is a modification of procedures used for undecalcified rat bone and Stomatococcus mucilaginosus.

Cultures were fixed and processed at room temperature (RT) under a fume hood. Solutions were added with a Pasteur pipet and removed by gentle vacuum aspiration. Other equipment used is shown in Figure 3. Cultures were fixed for 17-18 h in 10-20 ml of RT 2% phosphate buffered glutaraldehyde (422 mosm/KgH2O) within 5 m after removal from the incubator. After 3 (30 m) changes in 0.15 M phosphate buffer (PB = 209-213 mosm/KgH2O, pH 7.39-7.41), colony cut-outs (CCO) were made with a scalpel.
Ultrastructure of E. coli: An in vitro study of cells cultured in the presence of four gastrointestinal (GI) hormones
Authors: Henz Leo J. , Johnson Frank E.
Published: June 2020

Hormones are found in exocrine secretions entering the gut. They alter the morphology of many eukaryotic cells; whether they affect the morphology of enteric flora is unknown. In this study, we examined the ultrastructure of E. coli, a common bacterium in the mammalian gut, for morphological changes resulting from exposure to GI hormones.

E. coli (#11775 from American Type Culture Collection) were grown in protease-free trypticase soy broth (TSB) at 37°C for 18 hr to a concentration of 2 x 107 cells/ml. Pure synthetic hormones were used: sulfated C-terminal cholecystokinin octapeptide (CCK), pentagastrin (PG), cyclic somatostatin tetradecapeptide (SS), or the porcine form of secretin (SEC). These were individually added to. bacterial cultures in TSB to make 1 x 107 organisms/ml and 0.0, 0.5, 2.5, or 5.0 μg of hormone/ml, then incubated for 30 min at 37°C. The cultures were rapidly chilled and added to equal volumes of cold 6% glutaraldehyde in 0.2 M cacodylate buffer. After 30 min, the bacteria were concentrated by centrifugation (15 min at 4000 RPM) and the pellets suspended in cold 3% glutaraldehyde for an additional 15 min, followed by centrifugation. The pellets were resuspended in cold cacodylate buffer and stored at 2°C for 1-7 d. The cells were again centrifuged and the pellets were blotted with a strip of filter paper to remove excess fluid, then mixed with a drop of warm 2% agar. The agar suspensions were pipetted into cold saline. The resulting solidified extrusions were cut by hand into 2 mm segments for further processing in 1% OsO4 (with or without en bloc staining in 2% uranyl acetate (UA) in ethanol). Following dehydration in ethanol, rinsing in propylene oxide, and encapsulation in Epon-Araldite, thin sections were examined and photographed with a JEOL-100C microscope.
Ultrastructure study of morphogenesis of nuclear polyhydrosis virus of Ectropis grisescens
Authors: Liren Zhang , Dihua Chen , Jianhong Zhang
Published: June 2020

Ectropis grisescens Warren was a major pest of tea in central and southern area of China. A newly isolated baculovirus from the insect, the nuclear polyhedral virus of Ectronis grisescens Warren (EgW-NPV), was able to kill larvas of the insect and belong to single-embedded virus in morphology. We had reported in detail the morphogenesis and assembly of Prodenis Liture NPV, a multi-embedded baculovirus, in vivo.

Recently in our laboratory electron microscopy had been used for observing and analysing the ultrastructure of fine fibres and ribosomes during morphogenesis of EgW-NPV in EgW larvas cells infected by this virus.
The structure of CF1 ATP-synthase isolated from spinach chloroplasts
Authors: Boekema Egbert J.
Published: June 2020

F1 is the soluble part of the ATP-synthase complex, which catalyzes the synthesis of ATP. F1 is built up from five different subunits. Three copies of two large subunits α and β, with a molecular mass of about 55000, form the backbone of the protein. Spinach ATP-synthase has also three smaller subunits: gamma (35700), δ (20000) and ɛ (13000). They are located within the α3β3 structure, which can be seen as a hexagon in projection. By immuno-electronmicroscopy it was demonstrated that in the hexagonal (top view) projection the large α and β subunits are alternating.

No detailed three-dimensional structure of a F1 ATP-synthase is available. Therefore, some important features of the structure are not precisely known. One example is the shape of the large subunits.
An x-ray mapping study of the effects of aluminum on the distribution of calcium, potassium and phorphorus in the roots of Hordeum vulgare var. Kearney
Authors: Nichol B. , Oliveira L.
Published: June 2020

Alumninum toxicity in plants has been shown to reduce root length and the net uptake of nitrate, ammonium, and potassium. In contrast it was demonstrated that phosphate net uptake increased with Al treatment. Additions of calcium to the growth medium were shown to counteract these effects, particularly changes in root length. However the reason(s) for the anti-toxic effect(s) of calcium ions is not understood. One possibility is that Al displaces Ca from the plasmamembrane and/or the cell wall which in turn disrupts Ca-dependent transport processes within and on the cell surface. In this study we report on the effects of Al on Ca, K and P distribution in the roots of the barley variety Kearney using x-ray mapping of freeze-dryed material and discuss the results in terms of the general mechanism of Al toxicity.

Root material was obtained from 5day old plants grown in hydroponic solution with or without 50 μM Al. Excised root tips were mounted on specimen holders and plunged into liquid nitrogen after which the roots were faced off with a cyromicrotome.
Electron Microscope studies (TEM and SEM) of in vitro multiplication of Lavandula stoechas L.: I. regeneration from seedling shoot apex explants
Authors: Mesquita J. F. , Guimarães M. L. , Santos Dias J.D.
Published: June 2020

Available data concerning “in vitro” multiplication of Lavandula sps. are scarce and do not involve cytological studies. In this work, shoot initiation from shoot apex explants of Lavandula stoechas is analysed, for the first time, in light and electron microscopes (TEM, SEM). Following habitual sterilization, seeds of Lavandula stoechas were germinated on MS basal medium with 2% sucrose (W/v). From 9-days old seedlings, explants (shoot tips including a small distal segment of hypocotyl - fig. 1) were aseptically excised and cultivated in that basal medium added with organic components as in B5 medium of Gamborg et al., 10% (V/v) of coconut milk, 0.8% of agar and benzyl-amino-purine (BAP) at different concentrations (0-4 mg/1). The pH was adjusted to 5.6 and cultures were maintained at 25±1°C with fluorescent light (2000 lux) for 16 h/day.

High frequency of multiple shoot formation was achieved on media supplemented with BAP, the concentration of 1mg/l showing to be the optimal one (Table 1).
Dictyosome tubules, a conspicuous membraneous system of the plant cell
Authors: Mollenhauer H.H. , Morré D.J.
Published: June 2020

Tubules of about 30 run diameter are a conspicuous feature of most, if not all, Golgi apparatus cisternae (Fig. 1). The tubules may be configured as fenestrae, networks, or single outward projections around the edges of the cisternae. Coated, vesicle-like membrane buds are a common feature of tubules. Short lengths of tubules connect secretory vesicles to cisternae.

The function of the tubules is not known although they interconnect cisternae of closely spaced dictyosome stacks and have been postulated to be intermediates between endoplasmic reticulum and Golgi apparatus. Additionally, they may play a part, as yet undefined, in the movement of products between cisternae.

This report demonstrates that the peripheral tubules of the Golgi apparatus are a conspicuous membrane system of the cell, equal to, and often exceeding, that of the flattened parts of the Golgi apparatus cisternae.

Tubules were considered as cylinders of constant diameter with total lengths equal to the sum of all tubule segments.
Surface ultrastructure of the gill arch of the Chaetodiptus faber (Broussonet, 1782) (Pisces)
Authors: Eiras-Stofella D. R. , Fanta E.
Published: June 2020

The fish chaetodipterus faber caught at the Paranaguá bay (southern Brazil) had the gills gently removed from the right body side, rinsed with 0.9% NaCl solution, and fixed in 3% glutaraldehyde in 0.15M phosphate buffer (1:1); 1% osmium tetroxide in the same buffer was used for post fixation. After that the gill arches were rinsed and then dehydrated in a graded ethanol series, critical-point dried in liquid CO2, and coated with gold. They were viewed and photographed in a Philips scanning electron microscope.

At the pharingeal region of the branchial arch, the gill raker has many hooks with sharp pointed spines (Fig. 2). Between them and at its base, many taste buds protrude. The epithelium has typical polygonal pavement cells with concentrically arranged surface ridges (Fig. 5). The respiratory lamellae are triangular in shape (Fig. 4), rising from the branchial filaments, irregular in thickness (Fig. 1). At the base some globous structures were found (g). Chloride cell apical crypts are at the surface of the epithelium.
A new method for searching intracellular stereo structures in plant tissues
Authors: Yao Yaqin , Jiang Xuanli , Hu Dongwei
Published: June 2020

The procedure for specimen preparation consist of the following.

1.

fixing the plant tissues routinely;

2.

washing the blocks thoroughly in PBS buffer;

3.

immersing the blocks in a PEG (polyethylene glycol 4000) series (50, 70, 90, 100%) and embedding in pure PEG at 50°C, and cooling slowly to room temperature;

4.

cutting into thin sections 5-10 nm thick by LKB-V microtome;

5.

washing the sections a few times in water, dehydrating in a graded ethanol series, and drying in a critical-point dryer using liquid CO2;

6.

sputter-coating with gold palladium; and

7.

investigating in a Hitachi S-450 scanning electron microscope.

By this method, the distinct, uninjured intracellular stereo structures can be conveniently found without Joss of cell organelles. Moreover, there are advantages to studying their stereo relationships between various components of cells. Using wheat leaves, one can find chloroplasts, mitochondria, nuclei, nucleoli, and parts of the cytoskeleton system in the mesophyll cells and their sizes and distributions directly.
A potassium permanganate fixative for membranes in sections
Authors: Song Jindan
Published: June 2020

Potassium permanganate has been used as a fixative for the botanical specimen and membrane system in thin section by Glauert (1975). A new potassium permanganate fixative ( Trisodium citrate 60mM, Potassium chloride 25mM, Magnesium chloride 35mM, and Potassium permanganate 125mM ) for localizing membranous system in whole_mount cultured cells with standard trasmission electron microscopy and phase_contrast microscopy has been developed). Here, we report that using this new potassium permanganate fixative for membranous system in sections.

Cultured cells, CV_1 (African green monkey kidney epithelial cells), Balb/c 3T3 ( Mouse embryo fibroblast ) and MCF_7 (Human adenocarcinoma cell line) were used for this study. All cells were grown on 35mm plastic dishes in DME medium containing 5% calf serum at 37 c with 100% humidity and 5% CO2. Using the potassium permanganate fixative to fix the cells for about 7 minutes. After fixation, the cells were dehydrated in a graded series of ethanol.
Uranyl acetate staining under different conditions of preparation, storage and use
Authors: Cross R.H.M. , Hodgson A.N. , Bernard R.T.F.
Published: June 2020

Uranyl acetate is routinely used in the staining of thin sections of biological tissue for transmission electron microscopy. Although many methods for its preparation and use have been described, there is seldom reference to the reasons for variations in concentration, solvent, storage time and staining time. Likewise, possible variations in the effects of staining under different conditions are largely ignored. In order to gain clarity on this issue an attempt has been made to test three variables (solvent, storage time and use in light or dark) under controlled experimental conditions.

The tissues used for the experiment were the testis of a marine limpet, the gut epithelium of a fresh-water catfish, and the kidney of a rat; all of which were fixed and embedded by standard methods. The uranyl acetate solutions were prepared at the outset of the experiment and dispensed into small volumes and stored in the dark at 4°C until required.
A Scanning Electron Microscopy study of laser-cut hair
Authors: Hess W. M. , Gardner John S. , Srinivasan R. , Braren Bodil
Published: June 2020

Ablative photodecomposition with an ultraviolet laser was used for making clean holes in organic polymers. The purpose of this study was to determine whether similar procedures could be used to cut hair. Cross-sections of hair makes it possible to characterize shape and size of human and animal hair. The use of a laser provides a means to control the angle of cut and a means to cut hair without applying pressure to the hair shaft, preventing shape distortion. Then accurate cross sectional measurements can be obtained for area and perimeter determinations.

The laser was filled with argon and fluorine with helium as a buffer gas. The emitted pulses had a wavelength of 193 nm. The beam was narrowed by passage through a convex lens made of fused quartz. The intensity was 200 millijoules/sq.cm. and cutting was done in air. The greater the fluence the greater the depth of removal per pulse.
Detection of mRNAGFAP by post-embedding EM in situ hybridization
Authors: Erickson Page A. , Feinstein Stuart C. , Lewis Geoffrey P. , Fisher Steven K.
Published: June 2020

We have developed a technique that allows mRNA molecules to be localized within cells at extremely high (nanometer) resolution. Using a cDNA for glial fibrillary acidic protein (GFAP forms lOnm diameter intermediate filaments), we have localized the mRNAGFAP in three different cell types (optic nerve astrocytes, retinal astrocytes and retinal Miiller cells). One retina was experimentally detached to stimulate GFAP expression in retinal Miiller cells. Cells containing GFAP were identified by immunoelectron microscopy. Cat retinas and optic nerves (n=7) were fixed with 2% or 4% paraformaldehyde for 1.0 hr, dehydrated with dimethylformamide, and embedded in Lowicryl K4M resin. Thin sections, placed on nickel grids, were probed with biotinylated cDNAGFAP (overnight at 37°C) followed by streptavidin-gold conjugate (1.0 hr, 23°C).

In each of the three cell types that contain GFAP, the localization of the mRNAGFAP was the same. In the nuclei gold spheres were localized over amorphous, electron-dense regions within the euchromatin (presumably precursor mRNA).
A technique for the study of histozoic myxosporean cysts: SEM of faces of partially cut wax embedded blocks
Authors: Odense Paul , Cone David
Published: June 2020

Myxosporeans include many histozoic protist parasites of fishes in freshwater and marine environments worldwide and in a number of systems constitute important pathogens. Most species produce trophozoites that form obvious and often grotesque, cyst-like structure s within the host tissue. Traditionally, these trophozoites have been studied by means of either light or transmission electron microscopy. We have developed a simple technique whereby SEM can be used to supplement traditional light microscopical observations.

Specimens of Myxobolus lamellus Grinham and Cone, 1990 were chosen because of the unusual nature of the trophozoite cyst, which is compartmentalized instead of the hollow fluid-filled sac typical of most species. The material was collected from the secondary gill lamellae of Catastomus commersoni living in a small lake in south shore Nova Scotia, 45 km west of the city of Halifax. Live fish were transported to the laboratory and necropsied. Cysts were fixed in 10% neutral buffered formalin for several days before being dehydrated and embedded in Paraplast using routine histological techniques.
Detection of human cytomegalovirus infection in paraffin sections by Grocott’s methenamine silver stain for light and electron microscopy
Authors: Chien K. , Kim Y.K. , Shintaku I.P. , Van de Velde R.L. , Heusser R.C. , Danao F. , Geller S.A.
Published: June 2020

Grocott's methenamine silver stain (GMS) has been used histologically for identifying Pneumocystis carinii and fungal infections in paraffin sections of surgical specimens. However, current studies indicate that aggregates of human cytomegalovirus (HCMV) in the cytoplasm of infected cells are also stained by GMS and can be detected by LM. Since precipitated silver particles are electron dense, the presence of silver labelled HCMV virions can be easily located and confirmed by TEM.

GMS and light green stained paraffin sections positive for HCMV can be processed for TEM either by conventional procedures or as follows: Coverslips are removed by immersion in xylene. A few drops of 1% 0s04, freshly dissolved in xylene, are then pipetted onto each slide for 5 minutes. Prolonged osmication is to be avoided as it will cause reduction of the silver deposits. Slides are then rinsed in xylene and changed to 100% acetone. Substitution of acetone for xylene prior to resin infiltration will produce a better quality block for sectioning. The sections are embedded, polymerized and subsequently separated from slides as previously described. The light green staining is retained in the epoxy block, which facilitates tissue orientation and selection of areas for thin-sectioning.
Neurotoxicity of manganese in the teleost Tilapia
Authors: Herrera Annabelle A. , Catap Elena S.
Published: June 2020

Manganese is considered as an essential element for man and other animals. Although it is one of the trace elements least toxic to mammals, man-made pollution related to the steel industries and exposure to the mining of manganese ore represent potential hazards to organisms in these areas.

One of the target organ systems of manganese is the central nervous system (Beliles, 1975). Intake of its metal dust can lead to chronic manganese poisoning resembling Parkinson’s disease (Ferraz, et.al., 1988). Symptoms of this disease have been observed in human after prolonged chronic exposure to manganese (Scheuhammer and Cherian, 1981).

Studies being reported on manganese deal with mammals and are focused on its neurotoxicity, most of which are based on physiological and neurochemical mechanisms. There has been no report yet of morphological or ultrastructural abnormalities associated with manganese exposure. In this study, the effects of manganese on the morphology and ultrastructure of the brain of Tilapia finger lings will be discussed.

Tilapia fingerlings from Central Luzon State University, Muñoz, Nueva Ecija were acclimated prior to MnCl2 exposure.
Split-thickness calvarial autografts reinforced by hydroxylapatite/plaster for craniofacial bone reconstruction
Authors: Hanker J.S. , Turvey T.A. , Ovelmen-Levitt J. , Gaskin D.D. , Giammara B.L.
Published: June 2020

Calvarial or cranial (membranous) bone offers several advantages over the more generally utilized rib, iliac or pelvic (endochondral) autografts for the surgical reconstruction of craniofacial bone defects. Studies in humans showed that fresh autogenous membranous bone placed in soft tissue maintained its original size for several years. Autogenous endochondral bone from rib, ilium or tibia treated in the same manner was resorbed in 8 to 10 months. Later studies were performed in rabbits where membranous bone from the frontoparietal region was compared with endochondral iliac bone, after each had been implanted either subcutaneously or subperiosteally. Seventy-five percent of implanted endochondral bone was resorbed whereas the volume of implanted membranous bone increased after 1 year.
A simple method for exposing and examining the interior of fragile biological materials
Authors: Wasserman Arthur J. , Pedro Kato Y. , Silver Frederick H.
Published: June 2020

Examining the inside of delicate and fragile dry biomaterials is difficult because they are vulnerable to mechanical damage. Compression and sheering of a sample during exposure of the interior can produce artifacts making interpretation of the ultrastructure difficult. In this report a simple method for exposing and retaining the interior substructure of delicate specimens and mounting them for scanning electron microscopic (SEM) observation is described.

Collagen fibers were prepared as described previously. In brief, 1% collagen dispersion, prepared from bovine hide, was extruded through polyethylene tubing with an inner diameter of 0.28 mm into a 37°C, pH 7.5, fiber formation buffer. After 45 mins in the buffer, the fibers were rinsed in isopropyl alcohol for 4 hrs followed by distilled water for 20 mins. The fibers were then crosslinked.

The interior of collagen fibers were exposed by deep freezing 1 cm segments of fiber in liquid nitrogen. Using iris scissors the first and last piece of each segment (which contained ends previously exposed to the atmosphere) were snapped away and discarded. Each frozen segment was then snapped in half. By this method each half of the original 1 cm segment had a freshly cleaved top and bottom surface. The segments were transferred to an aluminum foil pouch (in liquid nitrogen).
Three-dimensional distribution of ribulose-1, 5-bisphosphate carboxylase/oxygemase during the early development of proplastids in dark-grown Euglena cells transferred to an inorganic medium
Authors: Ehara Tomoko , Sumida Shuji , Osafune Tetsuaki , Hase Eiji
Published: June 2020

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.
Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells
Authors: Ferguson D.J.P. , Berendt A.R. , Tansey J. , Marsh K. , Newbold C.I.
Published: June 2020

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).

We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).
Immunogold localization of fibrinogen (FIB) and its receptor on human platelets by conventional and intermediate-voltage EM (IVEM)
Authors: Hensler Mary E. , Hantgan Roy R. , Willard Andra S. , Lewis Jon C.
Published: June 2020

Platelet aggregation involves fib, which serves as a molecular bridge within hemostatic plugs. The interaction of fib with platelets is mediated by glycoprotein IIb/IIIa (GPIIb/IIIa), which binds fib after platelet activation. Ultrastructural studies have documented relocation of GPIIb/IIIa with long-term activation. However, little is known about GPIIb/IIIa redistribution during early activation. Reported is the use of immunogold chemistry along with thick-section stereo IVEM and TEM stereology to document the location of fib and GPIIb/IIIa during early activation.

Platelets were isolated from anticoagulated blood obtained following informed consent from human volunteers. Plasma proteins were removed by gel-filtration over Sepharose 2B in a Hepes-albumin-Tyrodes buffer. The gel-filtered platelets (GFP) were activated in suspension with 10 umol/L ADP in the presence of 2 mmol/L CaCl2 and in select experiments 100 μg/mL fib. GFP at various activation times were fixed in 1% glutaraldehyde, and the following monoclonal antibodies (mabs) were used to localize GPIIb/IIIa: P2 (AMAC, Inc.), AP-2 (provided by Dr. T. Kunicki), and 7E3 (an activation dependent mab from Dr. B. Coller).
Scanning probe microscopy: A new technology takes off
Authors: Elings Virgil
Published: June 2020

With the expanding use of the scanning tunneling microscope, the technology is developing into other scanning near field microscopes, microscopes whose resolution is determined by the size of the probe, not by some wavelength. The first available “son of STM” will be the atomic force microscope (AFM), a very low force profilometer which has atomic resolution and can profile non-conducting surfaces. The hope is that this microscope may find more applications in biology than the scanning tunneling microscope (STM), which requires a conducting or very thin sample.

In the past five years, the STM has progressed from curiosity to everyday lab tool, imaging surfaces with scans from a few nanometers up to 100 microns. When compared to an SEM, the STM has the advantages of higher resolution, lower cost, operation in air or liquid, real three-dimensional output, and small size. The disadvantages are smaller scan size, slower scan speeds, fewer spectroscopic functions and, of course, not as many of the nice features of the more mature electron microscopes. The AFM has similar features to the STM except that the detector and profiling tips are more complicated and more difficult to operate—disadvantages that will decrease with time.
Three Ways to Look at Muscle
Authors: Goldstein Margaret Ann
Published: June 2020

A pictorial history of muscle morphology from the 1960’s to the 1990’s shows the successive addition of new methodology and the combination of analytical techniques with descriptive approaches. These powerful images express the relationships between the cell components required for cycles of contraction and relaxation.

Although electron micrographs are used as pictures to illustrate a story, they are precise descriptions containing analyzable data. The vast quantities of information contained in a single image has been the impetus to make better procedures and technologies to extract and display selected information. One of the simplest methods of feature extraction that is still widely used is cropping images to limit the field of view. Selective staining allows visualization of long-range ordering of specific features in images from HVEM. Optical diffraction and optical reconstruction provide for enhancement of order, and stereological approaches allow for quantitation in studies of muscle protein lattices.
Generating and Comparing Three-Dimensional Images of Structures Obtained by Electron Microscopy and other Methodologies
Authors: DeRosier D. J.
Published: June 2020

“Subtract the mind,…and the eye is open to no purpose, which before did see.” “Before my eye can see the painting on the wall, this must…be borne into my phantasy, to be assimilated by my understanding.” (both attributed to 14th century philosopher-mystic, Meister Eckhart).

Images of models provide a way to look at structures. A well-executed model can embody the results of many studies in a way that our minds easily grasp. We learn from them, and we teach from them. They are especially important in structural studies because comprehension of spatial relationships is key to our understanding. The computer, with its ability to generate, color and animate three-dimensional objects, is a source of both good and evil when producing images of models.

Models are really analogies intended to illustrate particular attributes of a structure. A “dangerous pitfall is hidden in the very nature of analogies themselves. Every grade [of analogy] can be traced between remote analogies, and analogies which are so close that they pass into identities, and – paradoxically enough – it is often the remote analogies which have the greatest value, while it is the close analogies of which we have to beware. The misuse of an analogy by pressing it to the point at which it is confused with an identity, is one to which biological thought is particularly liable.” (Agnes Arber, 1953).