bluuebunny/crossref_metadata_2025_split huggingface dataset:
Germination and multiplication of Bacillus thuringiensis var. kurstaki in the midgut of Pieris canidia larva: An Electron Microscopic study
Authors: Cheung Wilkin W.K. , Lam Yui F. 
Published: June 2020

Presently Bacillus thuringiensis var. kurstaki (Btk, thuricide) is a popular microbial insecticide on market for controlling lepidopterous pests. The damage of Btk on lepidopterous larvae have been well documented. However, practically few references give sufficient ultrastructural details on the germination and multiplication of Bt spores and bacterial cells after infecting the larvae. The present study is aimed to fill the gap of the necessary information.Pieris canidia L. larvae were immersed in 2.5% (w/v) thuricide (40,000 IU, Sandoz Co.) spore-crystal suspension for 5 sec. dip and were put onto petri dishes for observation in various time intervals after blotted dry with filter paper. Control larvae had not been treated with Btk.
Correlation of ultrastructure with the mechanism of wax filament production in cork cells in Johnsongrass [Sorghum halepense (L.) Pers]
Authors: Paul R. N. , McWhorter C. G. 
Published: June 2020

Wax filament production has been previously reported to be a secretory function of costal and intercostal cork cells in johnsongrass leaf and sheath epidermis. The “waxy bloom” observed on the sheath of johnsongrass during certain stages of plant development is the result of massive quantities of long wax filaments (>200 um) deposited on the sheath cuticle. SEM investigations of intact and dewaxed sheath tissue have indicated that wax filaments are the result of extension of material through cuticular pores. These pores are observed in the cork cell cuticle in dewaxed tissue. The purpose of this investigation is to correlate cork cell ultrastructure with the process of wax filament production through the use of a procedure maximizing lipid retention in epoxy-resin embedded materials.Johnsongrass tissue used in this study was taken from greenhouse-grown plants ranging from 10 cm to 20 cm in height. Sheath tissue subtending the youngest leaves was used.
Portein-gold labelling of ultrathin sections of wheat spot mosaic-affected wheat plants
Authors: Zaychuk K. S. , Chen M. H. , Hiruki C. 
Published: June 2020

Wheat spot mosaic (WSpM), which frequently occurs with wheat streak mosaic virus was first reported in 1956 from Alberta. Singly isolated, WSpM causes chlorotic spots, chlorosis, stunting, and sometimes death of the wheat plants. The vector responsible for transmission is the eriophyid mite,Eriophyes tulipaeKiefer. The examination of leaf ultrastructure by electron microscopy has revealed double membrane bound bodies (DMBB’s) 0.1-0.2 μm in diameter. Dispersed fibrils within these bodies suggested the presence of nucleic acid. However, neither ribosomes characteristic of bacteria, mycoplasma and the psittacosis group of organisms nor an electron dense core characteristic of many viruses was commonly evident.In an attempt to determine if the DMBB’s contain nucleic acids, RNase A, DNase I, and lactoferrin protein were conjugated with 10 nm colloidal gold as previously described. Young root and leaf tissues from WSpM-affected wheat plants were fixed in glutaraldehyde, postfixed in osmium tetroxide,and embedded in Spurr’s resin.
Cytochemical and immunocytochemical localization of the endosperm cells of ginseng
Authors: Kim Eun-Soo , Yu Seong-Cheol , Kim Woo-Kap 
Published: June 2020

Storage material of endosperm cells digested by various enzymes is transported to the embryo. At this time, the cellulose of the endosperm cell wall is guessed to be hydrolyzed by the cellulase in order to help the storage material to move from the endosperm cell to the embryo. Therefore, this study has been carried out to investigate the localization of the cellulase activity on the endosperm cells of Panax ginseng C.A. Meyer with the cytochemical and immunocytochemical techniques during germination.Ripened red fruits of 4-year-old ginseng were collected at the cultivated field in Korea. After the sarcocarps were removed, the seeds were mixed with sands at the ratio of 1 to 5 to split the seed coat along the raphe. They were sown on moist filter paper in petri dishs and kept in the dark at 4 C. For the cytochemistry, tissues were fixed in Karnovsky fixative at 0 C for 1 hr, rinsed in 0.1 M phosphate buffer, pH 7.2, and stored in this buffer at 0 C for 16 hr.
Cytoskeleton in tobacco plant cells after propane jet freezing and freeze substitution
Authors: Ding Biao , Turgeon Robert , Parthasarathy M.V. 
Published: June 2020

Microfilaments in plant cells are very labile and in some cells difficult to preserve by chemical fixation. Single microfilaments are even more labile and are rarely preserved. Cryofixation is so far the best means to preserve these labile cellular components for electron microscopy. However, previous studies only dealt with single plant cells because of the shallow depth of good freezing limited by the technique (plunge freezing). Here we report our results of preserving cytoskeleton in plant leaf and root cells using propane jet freezing and freeze substitution.Tobacco (Nicotiana tabacum L. var. Maryland Mammoth) plants were grown under greenhouse conditions. A developing leaf was cut from a two-month old plant and immersed in a 0.2 M sucrose solution containing 20 mM MES, 20 mM CaCl2 and 20 mM KCl. Samples of 1 mm2 were cut out of the leaf and incubated for 10 to 30 minutes. The leaf samples were then frozen in a commercial propane jet-freezer (Model MF7200, KMC, Tucson, Arizona).
Flat embeddment of monolayer cells, tissue sections, and other cellular materials attached onto glass substrate
Authors: Chang Jeffrey P. , Wang Jaang J. 
Published: June 2020

Flat embeddment of certain specimens for electron microscopy is necessary for three classes of biological materials: namely monolayer cells, tissue sections of paraffin or plastics, as well as cell concentrations, exfoliated cells, and cell smears. The present report concerns a flat-embedding technique which can be applied to all these three classes of materials and which is a modified and improved version of Chang's original methodology.Preparation of coverglasses and microslides. Chemically cleaned coverglasses, 11 × 22 mm or other sizes, are laid in rows on black paper. Ink-mark one coner for identifying the spray-side of the glass for growing cells. Lightly spray with Teflon monomer (Heddy/Contact Inductries, Paterson, NO 07524, U.S.A.) from a pressurized can. Bake the sprayed glasses at 500°F for 45 min on Cover-Glass Ceramic Racks (A. Thomas Co. Philadelphia), for Teflon to polymerize.Monolayer Cells. After sterilization, the Teflon-treated coverglasses, with cells attached, are treated or fixed in situ in Columbia staining dishes (A. Thomas Co., Philadelphia) for subsequent processing.
Analysis of rat adrenocortical cells by analytical color fluorescence EM
Authors: Nakano Tohru , Ning Gang , Fujimoto Toyoshi , Koike Hirotami , Ogawa Kazuo 
Published: June 2020

Distribution of various steroids in adrenocortical cells has not been unequivocally demonstrated, because specific histochemical techniques were not available. In recent years, we have developed an analytical color fluorescence electron microscope (ACFEM) which was assembled on the basis of a high resolution SEM (AKASHI : DS-130). The ACFEM enabled us to detect and analyze cathodoluminescence (CL) which is a very weak light emission under electron beam bombardments, and color CL images could be obtained simultaneously with secondary electron images of the same field. We have previously reported that rat adrenocortical cells emit strong blue-green CL, and intermediary metabolites of the steroid hormones can be separated by CL spectroscopy with the ACFEM. In the present study, effects of hypocholesteremic drugs and adrenocorticotrophic hormone (ACTH) on the lipid droplets of adrenocortical cells were examined by employing the ACFEM.Adult male Wistar rats weighing 250-300g were used, and divided into four groups :
Study on EPM to microvascular cast of human brain
Authors: Zhou Shanmin 
Published: June 2020

While directing the microvascular cast of a sample of fresh brain under binocular microscope with methyl methacrylate, the specimen surface vacuum evaporation treating unit has been sprayed 100aA golden membrane for microvascular cast, on the condition of accelerating voltage 20kV and probe current 0.02nA, with the scanning of EPM Shimadzu Corporation JAPAN. You will find that the corterartery of brain substance artery has various types of the branches, the blood capillary circulation tallies one with another to form well developed blood capillary network and there are cobble-like marks formed by internal cells on the surface of arteriole blood vessels.Mixing nine methyl methacrylate with one methyl acrylate and adding into it 6% benoyl peroxide of the liquids above, putting this mixture into a cone-shaped bottie , and heating the liquid to 80-P5 C, when the solution is gradually getting dense set and is ready to gettogether.
Effect of verapamil on myocardial changes in experimental hypertensive rats
Authors: Yilmazer Selma , Seçkin Ismail , Tasyürekli Mustafa , Arda Oktay , Satiroglu Güngör 
Published: June 2020

Recent experimental and clinical studies have reported on the effectiveness of calcium antagonists in the treatment of hypertension. The influence of such therapy on the morphologic features of heart, however has not been systematically studied. In the present study we have investigated the effect of verapamil, a calcium antagonist, on blood pressure and on ultrastructural features of myocardium in rats made hypertensive with DOCA + salt.Experiments were carried out with 24 female Wistar rats, 4 weeks of age. The animals were divided into 3, 8 animals per group. Group I was considered as the control group. Group II was injected intraperitoneally with 3 mg/kg daily of DOCA for 5 weeks and 154 NaCl was added in their drinking water. Group III received 8mg/kg daily of verapamil hydrochloride (Isoptin, Knoll Pharmaceutical Co.) orally, in additon to DOCA and salt. Five weeks after the start of the experiment systolic blood pressure was recorded and animals were killed. Left ventricle was dissected and prepared for electron microscopy.
Morphologic alterations in porcine endothelial cells by the plant toxin metabolite, monocrotaline pyrrole
Authors: Hogan M.E. , Wagner J.G. , Klomparens K.L. , Roth R.A. 
Published: June 2020

Animals treated with the pyrrolizidine alkaloid metabolite, monocrotaline pyrrole (MCTP), show a progressive pulmonary hypertension associated with interstitial edema and smooth muscle thickening of muscular vessels in the lung. To determine what effect the blood borne toxin has on the endothelium, primary tissue cultures were treated with MCTP and were examined using the scanning electron microscope.Porcine endothelial cells were isolated, cultured, then plated on tissue culture slides and Millipore filters. The effect of cell density was examined by plating at three different concentrations, the most dense (control cells) being confluent at time of fixation. Cells received no treatment, the vehicle (N,Ndimethylformamide), 5μg MCTP/ml or 50μg MCTP/ml 24 hours after plating and were allowed to grow for an additional four days.The most striking changes were cell hypertrophy and an alteration in the cell's plating character at a dose of 50μg MCTP/ml. Hypertrophy of the endothelial cells was evident at the 50μg MCTP/ml dose, at which the treated cells approached 4 to 5 times the size of the untreated cells.
Elemental silicone analysis in human breast and capsular tissue surrounding prostheses and expanders
Authors: Jennings Debby , Morykwas Michael , DeFranzo Anthony , Argenta Louis 
Published: June 2020

polydimethylsiloxane is the most frequently used polymer for manufacture of breast prostheses and soft tissue expanders. The diffusion of lower molecular weight molecules and there lease of silicafiller from the outer shell have been speculated to cause capsular contraction (capsule formation is normal, capsular contraction is pathologic). Previous research has identified silicone in the tissue surrounding gel-filled implants. This preliminary project analyzed human breast tissue and capsular tissue from around expanders and implants for the presence of silicone by electron dispersive x-ray analysis (EDXA).Tissue samples were divided into four categories based on device: single lumen, standard bleed gel filled implant (n=2); single lumen, low bleed gel filled implant (n=2); double lumen (saline outer lumen) gel filled implant (n=3); and expander or inflatable prostheses (nogel) (n=4). Breast and subcutaneous tissue external to the capsules were used as controls (n=4).
Ultrastructural and immunocytochemical studies of the rat hypothalamo-neurohypophysial system processed by rapid freezing and freeze-substitution fixation
Authors: Shioda Seiji , Nakai Yasumitsu , Ichikawa Atsushi , Ochiai Hidehiko , Naito Nobuko 
Published: June 2020

The ultrastructure of neurosecretory cells and glia cells in the supraoptic nucleus (SON) of the hypothalamus and the neurohypophysis (PN) was studied after rapid freezing followed by substituion fixation. Also, the ultrastructural localization of vasopressin (VP) or its carrier protein neurophys in II (NPII) in the SON and PN was demonstrated by using a post-embedding immunoco1loidal gold staining method on the tissue sections processed by rapid freezing and freeze-substitution fixation.Adult male Wistar rat hypothalamus and pituitary gland were quenched by smashing against a copper block surface precooled with liquid helium and freeze-substituted in 3% osmium tetroxide-acetone solutions kept at -80°C for 36-48h. After substituion fixation, the tissue blocks were warmed up to room temperature, washed in acetone and then embedded in an Epon-Araldite mixture. Ultrathin sections mounted on 200 mesh nickel grids were immersed in saturated sodium metaperiodate and then incubated in each of the following solutions: 1 % egg albumin in phosphate buffer, VP or NPII (1/1000-1/5000) antiserum 24h at 4°C, 3) colloidal gold solution (1/20) 1h at 20°C. The sections were washed with distilled waterand dried, then stained with uranylacetate and lead citrate and examined with Hitachi HU-12A and H-800 electron microscopes.
Membranous diffusion of Dil (a phospholipid-like fluorescent probe) in retrogradely labeled neurons: Analysis with the EM
Authors: Cunningham D.E. , von Bartheld C.S. , Rubel E.W 
Published: June 2020

The compound 1,1’-dioctadecyl-3,3,3’,3’-tetramethylindocarbocyanine perchlorate (Dil) is a fluorescent molecule with diffusion properties similar to those of phospholipids. Intramembranous (“lateral”) diffusion of Dil is preserved in aldehyde-fixed tissues and has been used to label neuronal pathways. We found that Dil-label, when illuminated (“photo-converted”) in the presence of diaminobenzidine (DAB), forms an electron-dense reaction product that is suitable for EM analysis. We show that the Dil molecule has a surprising diffusion ability and differential affinitiy to internal membranes after retrograde diffusion along neurites in fixed tissue. This finding may have implications for normal diffusion of phospholipids along intracellular pathways in vivo.Two 20-day old White Leghorn chick embryos were anesthetized and perfused intracardially with 0.1M phosphate buffer (PB, pH 7.4) followed by perfusion with 2% paraformaldehyde and 1% glutaraldehyde in PB.
Horseradish peroxidase as a cytochemical marker for altered cell membrane permeability in cultured myocytes after oxidative stress
Authors: Ashraf M. , Aida K. , Oguro T. 
Published: June 2020

The development of a selective staining technique is important for the study of cell membrane permeability altered under different experimental conditions. This is particularly useful if the same technique or procedure is used for both light and electron microscopy examination. In this study, the effect of oxidative stress in the cultured myocytes using lanthanum (La+++), ruthenium red (RR) and horseradish peroxidase (HRP) as cytochemical markers for leaky myocytes was studied. Myocytes from adult rat hearts were isolated and cultured in modified MEM (Sigma Chemical Co.) at 37°C. Myocytes were exposed to 300 μM H2O2 for 15, 30 and 60 minutes. The cells were then rinsed, incubated in 1% HRP, 5 mM La+++ or 0.3. RR, and were fixed in 2.5% buffered glutaraldehyde for 1 hour. The HRP-treated cells were incubated in diaminobenzidine as described.After treatment with H2O2 for 15 minutes, all myocytes remained rod-shaped, and their number was decreased to 80% after 60 minutes. The staining of cells with La+++ could not be visualized under the light microscope even in the round cells, and with RR, only heavily damaged cells were distinguishable from normal cells. HRP staining yielded excellent results.
Immunogold labeling of the calcium binding protein synexin in isolated adrenal chromaffin granules and chromaffin cells
Authors: Kuijpers Gemma A.J. , Pollard Harvey B. 
Published: June 2020

Exocytotic fusion of granules in the adrenal medulla chromaffin cell is triggered by a rise in the concentration of cytosolic Ca2+upon cell activation. The protein synexin, annexin VII, was originally found in the adrenal medulla and has been shown to cause aggregation and to support fusion of chromaffin granules in a Ca2+-dependent manner. We have previously suggested that synexin may there fore play a role in the exocytotic fusion process. In order to obtain more structural information on synexin, we performed immuno-electron microscopy on frozen ultrathin sections of both isolated chromaffin granules and chromaffin cells.Chromaffin granules were isolated from bovine adrenal medulla, and synexin was isolated from bovine lung. Granules were incubated in the presence or absence of synexin (24 μg per mg granule protein) and Ca2+(1 mM), which induces maximal granule aggregation, in 0.3M sucrose-40m MMES buffer(pH 6.0). Granules were pelleted, washed twice in buffer without synexin and fixed with 2% glutaraldehyde- 2% para formaldehyde in 0.1 M phosphate buffer (GA/PFA) for 30 min. Chromaffin cells were isolated and cultured for 3-5 days, and washed and incubated in Krebs solution with or without 20 uM nicotine. Cells were fixed 90 sec after on set of stimulation with GA/PFA for 30 min. Fixed granule or cell pellets were washed, infiltrated with 2.3 M sucrose in PBS, mounted and frozen in liquid N2.
STEM analysis of Janssen AuroProbe One
Authors: Hainfeld James F. 
Published: June 2020

The announcement of a smaller (1.0 nm) colloidal gold immunolabel by Janssen Life Sciences recently has heightened the hopes of many researchers to be able to label at higher resolution or have a smaller probe that could better access secluded antigens that are frequently accessible to fluorescent labeled antibodies or Fab fragments but not to the usual 3.0 to 5.0 nm colloidal gold immunolabels. Because the 1.0 nm gold is difficult to visualize directly in the TEM, it must usually be enhanced by a silver developer that nucleates on the gold and grows to grains that are of a useful size.While AuroProbe One has met with some success, some shortcomings have been found. One is that the silver developer can self nucleate, giving some false spots. Also, the grains do not grow uniformly and yield an irregular staining.This report, however, takes a look at the AuroProbe One directly using the high (0.25 nm) resolution STEM in darkfield where 1.0 nm particles are easily seen.
Organs of a Baikal seal affected by a morbillivirus
Authors: Belykh O.I. , Likhoshway Ye.V. , Solodun Yu.V. , Goldberg O.A. , Kumarev V.P. 
Published: June 2020

The population of Baikal seals Phoca sibirica has been plagued in 1987-88 by an unknown disease. Oligonucleotide probing of nucleic acids isolated from tissues of ill and dead animals, as well as immunological evidence and clinical data suggested that seals were infected by a morbillivirus. Morbillivirus antigen has been vizualized in dead seal tissues by immunoelectron microscopy (preembedding technique).The present report gives outline of electron microscopic studies of the tissues of infected Baikal seals. Morbillivirus antigens were vizualized as clusters of gold spheres by postembedding technique with monoclonal antibodies against measles virus and protein A-colloid gold conjugates in nuclei and cytoplasm of liver and kidney cells. Some clusters were associated with virus-like particles having a diameter of 80-100 nm. Electron microscopy of ultrathin sections stained with uranyl acetate revealed nucleocapsides having length of up to 1400 nm, and a diameter of 13-17 nm, morphologically similar to measles and seals distemper virus.
Visualization of DNA and DNA-protein complexes by TEM
Authors: Griffith Jack D. 
Published: June 2020

A large class of DNA and DNA-protein complexes of great interest to modern molecular biologists lie in a realm of size and complexity that it is too large for structural approaches using X ray diffraction or NMR techniques. Such complexes are usually highly irregular so that EM methods employing the formation of 2 dimensional crystals or dense-packing followed by image averaging are not usable. Examples of such complexes include topoisomerase II heterodimers bound to supercoiled DNA, plasmid DNAs being replicated by the battery of nearly 20 different proteins that initiate and carry out replication in E. coli, complexes of reverse transcriptase enzyme degrading the RNA strand of an RNA/DNA hybrid duplex, and many of the recombinational intermediates of DNA strand exchanges. In the latter complexes large protein scaffolds built of hundreds of RecA protein monomers form filaments with in which the events of DNA strand exchange occur.To visualize such large and complex structures the demands of the biochemical reactions must be given first prior ity: is ATP, glycerol, or salt required for the on going reactions? Do the reactions occur at room temperature or only at 37 degrees? Efforts in this laboratory have been focused on determining which of the various routes for visualizing macromolecules provides the best general approach to obtaining useful structural information that can be directly related to the biochemical processes.
Analysis of Myofibrillar Organization and Degeneration by Fluorescence Confocal Microscopy
Authors: Sussman Mark A. 
Published: June 2020

Myofibrillar degeneration is an important pathological process in progressive cardiomyopathy leading to heart failure. Loss of myofibrils in vivo has been observed in both adaptive cardiac responses (i.e. hypertrophy) as well as in chemotherapeutic use of antitumor drugs with cardiotoxic side effects (i.e. doxorubicin). The molecular mechanism(s) of myofibrillar degeneration are poorly understood in comparison with the sequence of events involved in myofibrillar assembly and organization. Maintenance of myofibril integrity is dependent upon a variety of factors, including contractile protein stoichiometry and protein kinase activity.The repeating sarcomeric architecture of myofibrils is well suited to structural analysis, since disruption of normal organization is easily visualized by fluorescence microscopy. Many antibodies are available for use in observation of myofibril structure (see Table at right). Confocal microscopy provides advantages in studies of myofilament organization by allowing for direct and accurate measurement of distances to within 0.2 βm and the ability to perform vertical sectioning through individual cells. This vertical (Z-axis) sectioning can be used to select the focal plane within the cell for observation, resulting in higher resolution images by reducing fluorescent signals from above and below the plane. Image analysis software enables the user to create projections of optically sectioned cardiomyocytes which can be rotated to reveal interior structural relationships previously unobserved with single sections or conventional epifluorescence microscopy. Examples of image analysis will highlight useful features such as distance measurement, periodicity, pixel intensity, colocalization of dual labels, and three dimensional reconstruction.