bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron-beam-induced reactions at surfaces
Authors: Smith David J. , McCartney M. R. 
Published: June 2020

It is well-known that the intense electron irradiation needed to record HREM images or micro-analytical spectra is liable to cause permanent microstructural changes in the specimen region undergoing observation or analysis. Beam-induced modifications at surfaces are even more likely because of the increased probability of permanent loss of material and the likelihood of reaction with constituents of the residual microscope vacuum. In this short review, we first survey the mechanisms available for beam-induced surface reactions, then briefly summarize recent observations of surface modifications and finally discuss their validity for surfaces relative to other reaction mechanisms described elsewhere. Since our primary interest here is in the possibilities for eliciting atomic-scale local information using HREM or microanalytical techniques, consideration is restricted to inorganic solids which are far less susceptible to damage by the electron beam than organic materials.Mechanisms. There are two basic mechanisms covered by the generic term “radiation damage” which could lead to electron-beam-induced surface reactions: ballistic or knock-on displacement whereby there is momentum exchange with an incident electron which may be sufficient to cause atomic displacement; and radiolytic processes which involve electron-electron interactions.
Mucous secretion as observed after ultrarapid freezing and freeze substitution
Authors: Luchtel D.L. 
Published: June 2020

Most molecules synthesized for extracellular transport are believed to be secreted from the cell by exocytosis. Exocytosis is also generally accepted as the mechanism of mucous cell secretion. We are studying the control of mucous and fluid secretion in a gastropod mollusc, Agriolimax columbianus, and have shown that it is an excellent model for the study of mucous secretions because of the copiousness and precise control of these secretions and the fact that they are released onto an exposed body surface, rather than within body cavities. Our observations of chemically-fixed material (glutaraldehye followed by osmium) showed “omega figures” typical of mucous vesicle exocytosis. On the other hand, in vivo observations showed that membrane-bound vesicles were shed intact from mucous cells.2 As an alternative to chemical fixation, we used a physical method of fixation, ultrarapid freezing, to determine more accurately the ultrastructural basis of mucous cell secretion.Intact body wall of the terrestrial slug, A. columbianus, was frozen with a Cryopress™ (Med-Vac Inc., St. Louis, MO) by slamming the tissue against the face of a polished copper block cooled in liquid N2 The frozen tissue was then freeze-substituted in cold (-80°C) osmium-containing acetone for several days, then brought to room temperature and embedded in Epon. Sections for EM were observed in a JEOL-100S TEM.
EM immunocytochemical localization of rhodopsin and IRBP during retinal development
Authors: Ulshafer R. J. , Hauswirth W.W. , van der Langerijt A. 
Published: June 2020

Two rod photoreceptor cell-specific proteins, rhodopsin and interphotoreceptor retinoid binding protein (IRBP), were localized during fetal development of the bovine retina using immuncicrytcichemistry. Rhodopsin is the light sensitive protein that, when activated, begins the process of transducing light energy to an electrical response. IRBP is a carrier protein that shuttles light-isomerized vitamin A (retinol) between the rod outer segment and the overlying retinal pigment epithelium where it is recycled to its light-sensitive form. Rhodopsin has been previously imimmocytochemically localized to rod (but not cone) photoreceptor outer segment membranes. IRBP has been localized to the subretinal space using immunocytochemistry.Retinas were obtained from fetuses at approximately 4, 5, 6, 7, and 8 months of gestation, fixed in 4% paraformaldehyde and 0.5% glutaraldehyde, and embedded at 40°C in epoxy resin. Thin sections were mounted on Ni grids and incubated with antibodies raised against the purified antigens: a mouse monoclonal anti-rhodopsin or a rabbit polyclonal anti-IRBP. A second antibody (Goat-anti-mouse or Goat-anti-rabbit) was conjugated with 15 nm Au particles and reacted with the sections. Control incubations were made using pre-immune rabbit serum and mouse monoclonals made against other tissue or bacterial sources.
Midgut infection of

Heliothis Zea

(Lepidoptera: Noctuidae) by cytoplasmic polyhedrosis virus
Authors: Bong C. F. J. 
Published: June 2020

The cytoplasmic polyhedrosis virus (CPV, Family Reoviridae) is an entomopathogen with a very wide host range, affecting mainly lepidopterous insects. The virus often causes chronic infections in insects, infecting mainly the midgut epithelium. Detailed studies of the effects of CPV on silkworm, Bombyx mori, have been done by Japanese workers , but there is very little information on the histopathology of CPV on other insects.In this study, 5-day old corn earworm (H. zea) larvae were infected per os with CPV. Control larvae were fed sterile water. The midgut was dissected out at 20, 48 and 72h post-treatment for both SEM and TEM studies. In the SEM study the midgut was fixed in 2.5% glutaraldehyde in phosphate buffer at pH 7.2, postfixed in buffered 2% osmium tetroxide at room temperature, dehydrated in ethanol, cryofractured in liquid nitrogen, critical-point dried, mounted, coated with gold-palladium and examined in a Hitachi HHS-2R scanning electron microscope at 20 kV. In the TEM study, the tissues were fixed in half-strength Karnovsky's fixative, postfixed in buffered cold 2% osmium tetroxide, en bloc stained in aqueous 0.5% uranyl acetate, dehydrated in ethanol and embedded in Spurr resin. Ultrathin sections were cut with glass knives, sequentially stained in aqueous uranyl acetate and lead citrate, and observed in a Zeiss 109 transmission electron microscope at 50 kV or a Siemens 101 at 80 kV.
Validation of convection-limited cooling for Electron Microscopy
Authors: Bailey Stuart M. 
Published: June 2020

Rapid freezing is a universal method of sample fixation for electron microscopy. Freeze-fracture replication, low temperature embedment and cryo-sectioning, and cryo-microscopy all depend on freezing specimens rapidly enough so that structure can be preserved unaltered. The most common method of rapid freezing is plunging specimens directly into liquid cryogens. In an earlier study, convection from the cryogen to the specimen was predicted to be the limiting step in rapid freezing of small samples for electron microscopy when the Biot modulus, (h V /kA) which determines the ratio of convective to conductive heat transfer, is less than 1. For convection-limited cooling, cooling rates are proportional to the surface area/volume ratio (A/V), independent of the sample thermal conductivity (k), linearly dependent on the heat transfer coefficient between the liquid cryogen and the specimen (h), and inversely proportional to the product of sample density and heat capacity (pCp):Ts and Tc are the sample temperature and the cryogen temperature, respectively.
The effect of 2,3,4-trimethylpentane on the ultrastructure of proximal tubular cells in primary cell culture
Authors: Mattie D.R. , Maslanka J.J. , Del Raso N.J. , Chase M.R. 
Published: June 2020

To aid in the assessment of the risk of Air Force personnel working with hydrocarbon fuels and compounds, an attempt was made to further characterize the nephropathy that results from exposure to hydrocarbons. The purpose of this study was to isolate and establish purified primary cultures of male rat proximal tubular cells suitable for experimental exposure to sublethal concentrations of solubilized 2,3, 4-trimethylpentane (TMP), a model hydrocarbon. Experiments were conducted to evaluate the cytotoxicity and metabolism of solubilized TMP in media containing or lacking the protein albumin.Proximal tubule cells in primary suspension culture were exposed to one of the following levels of TMP: 7.9, 12.0, 15.7, 19.1 or 25.5 mM. After 4 hours of exposure, pelleted cells were fixed for transmission electron microscopy by resuspension in 2% glutaraldehyde and 2.5% paraformaldehyde in 0.1M cacodylate buffer at pH 7.4. After a minimum fixation of at least 24 hours, the cells were post-fixed with 2% osmium tetroxide in 0,1M cacodylate buffer at pH 7.4. Cells were processed into Polybed 812 plastic capsules. Sections one micron thick, were cut in order to verify that cells were intact and suitable for thin sectioning. Thin sections (60- 90 nm) were cut on an ultramicrotome using a diamond knife. Thin sections, stained with uranyl acetate and lead citrate, were examined with a transmission electron microscope at 60 kV. Photographs of representative proximal tubule cells were taken at three levels of magnification.
High-resolution SEM of kidney tissue using cryo-techniques
Authors: Walther P , Herter P , Hentschel J , Hentschel H 
Published: June 2020

The kidney is a complex zonated organ with a variety of different cell types. For the study of the functional and morphological features, the precise localization in the zones is relevant, which requires the evaluation of rather large portions of tissue. Transmission electron microscopy of replicas of tissue is limited by difficulties to obtain sufficiently large specimens. In order to overcome this problem cryopreparation methods and high resolution field emission scanning electron microscopy (SEM) were used.1 mm3 cubes of perfusion fixed rabbit kidneys cryoprotected with glycerol were frozen by plunging into liquid propane. For further preparation two different methods were employed.1: Samples were fractured in liquid nitrogen with a scalpel, freeze substituted using methanol with glutaraldehyde and osmiumtetroxid, warmed to room temperature, critical point dried, and coated by electron gun evaporation with 2 nm of platinum at an angle of 45°, and 10 nm of carbon perpendicularly.
Immunolabeling of vitellogenin in the oocyte of viviparous fish, Poecilia reticulata
Authors: Hori Reiji , Phang Violet , Toong Jin Lam 
Published: June 2020

The guppy is viviparous and fertilization is internal. The spermatozoa are introduced by gonopodium of the male and the fertilization may occur upon the completion of maturation. The maturation of the primary oocyte probably starts immediately after puturition. The present study is to observe the changes of the follicular layer and egg cortex in the oocyte of the guppy and also to observe the accumulation of vitellogenin in the oocyte by use of immunolabeling method.Highly purified vitellogenin from the fish was used as immunogen to obtain rabbit anti-vitel 1ogenin antibody. Immunoglobulin (IgG) fraction was prepared by precipitation of the antiserum with 50% ammonium sulfate followed by gel filtration through Toyopearl HW55S column chromatography.The oocyte of the guppy, Poecilia reticulata were obtained by dissecting the female. Pre-embedding technigue was applied to immunolabeling of vitellogenin. The oocytes fixed for five hours in chille d 1% g l utaraldehyde and 2 % paraformaldehyde solution diluted with 0.1 M phosphate buffer (pH: 7.0)
Cytochemical studies of the multivesicular bodies
Authors: Tang Xueming 
Published: June 2020

Multivesicular bodies were observed frequently in electron microscope photographs of Leydig cells from normal adult rat testes. Their formation, evolution and fate were analyzed morphologically in preparations treated to show cytidine monophosphatase ( CMPase ) activity and in animals sacrificed at various time intervals ranging from 5 minutes to 2 hours after a single intratesticular injection of cationic ferritin. The CMPase medium contains 2mM cerium chloride, 2mM cytidine monophosphate, 5mM manganese chloride and 40mM sodium acetate buffer ( pH 5.0 ) with 4% sucrose. Cationic ferritin was used as a tracer for demonstrating the endocytic activity of Leydig cells.Cytochemical experiments showed that, in contrast to lysosomes which were CMPase positive, the premultivesicular bodies and the pale multivesicular bodies were CMPase negative. The dense multivesicular bodies were frequently apposed to strongly reactive lysosomes and they aquire their hydrolytic enzymes by fusion with lysosomes and showed CMPase activity.
Localization of DNA in chromatin using ESI and osmium ammine staining
Authors: Woodcock C.L. , Horowitz R.A. , Bazett-Jones D. P. , Olins A.L. 
Published: June 2020

In the eukaryotic nucleus, DNA is packaged into nucleosomes, and the nucleosome chain folded into ‘30nm’ chromatin fibers. A number of different model structures, each with a specific location of nucleosomal and linker DNA have been proposed for the arrangment of nucleosomes within the fiber. We are exploring two strategies for testing the models by localizing DNA within chromatin: electron spectroscopic imaging (ESI) of phosphorus atoms, and osmium ammine (OSAM) staining, a method based on the DNA-specific Feulgen reaction.Sperm were obtained from Patiria miniata (starfish), fixed in 2% GA in 150mM NaCl, 15mM HEPES pH 8.0, and embedded In Lowiciyl K11M at -55C. For OSAM staining, sections 100nm to 150nm thick were treated as described, and stereo pairs recorded at 40,000x and 100KV using a Philips CM10 TEM. (The new osmium ammine-B stain is available from Polysciences Inc). Uranyl-lead (U-Pb) staining was as described. ESI was carried out on unstained, very thin (<30 nm) beveled sections at 80KV using a Zeiss EM902. Images were recorded at 20,000x and 30,000x with median energy losses of 110eV, 120eV and 160eV, and a window of 20eV.
Some Ultrastructural Aspects of Chronic Gastritis
Authors: Bartel Hieronim , Orkisz Stanislaw , Chojnacki Jan 
Published: June 2020

Despite numerous observations and publications on the aethiology and pathogenesis of chronic gastritis many questions remain unanswered (1,2,3,4,6). Views on the aethiolcgy of chronic gastritis changed when in 1982 Campylobacter pyloridis (later named Campylobacter pylori CP) was first isolated in Western Australia from the stomach of patients with gastritis lesions and peptic ulceration (5).The aim of this study, carried out with cooperation with gastroenterologist, has been to investigate the ultrastructural changes in gastric surface epithelium and lamina propria in selected patients endoscopicaUy diagnosed gastritis.Observations have been carried out on 20 patients (10 men and 10 women). Biopsy material was obtained during endoscopy. In cases when the presence of bacteria has been confirmed further E M investigations have been introduced. Semithin sections for LM observations and ultrathin sections for EM were prepared according to routine EM technique.CP was found both on the airface of gastric epithelium cells, and what has not been reported so far, inside the lumen of the fundic glands (Fig. 1).
Effects of prenatal ethanol exposure on primate cardiac mitochondria
Authors: Pomphrey M. , Uphoff C. , Nyquist-Battie C. 
Published: June 2020

Fetal alcohol syndrome affects the development of the cardiac tissue in children, causing ventral septal defects and ventricular hypertrophy. Initial ultrastructural studies using rodents revealed mitochondria as the primary organelle affected by ethanol. Mitochondria from these animals displayed the classic pattern of mitochondrial degradation: condensation, crystolysis, and vacuolization. However an inherent problem existed in these models: the rodent heart is still immature at birth and full cardiac development does not occur until 18 days post-partem. This study uses the primate Macaca nemestrina in order to more closely parallel the cardiac development of a human infant.Furthermore, alcohol was administered in periodic doses to simulate binge drinking.Mothers were given weekly doses of one of the following isocaloric treatments: 0.0, 0.3, 0.6. 1.2, 1.8. or 4.1 g ethanol per kg body weight of the dam from week one of pregnancy until full-term. At birth the animals were removed from their mothers and hand-reared with appropriate peer contact.
Oxygen radicals participate in alloxan-induced pulmonary EDEMA
Authors: Kawada Tomoo , Arakawa Michio , Kambara Kenjiro , Segawa Takashi , Ando Fumio , Oda Hiroshi , Nakahara Koji , Hirakawa Senri , Emura Shoichi , Shoumura Shizuko , Isono Hideo 
Published: June 2020

We know that alloxan causes increased-permeability pulmonary edema and that alloxan generates oxygen radicals (H2O2, O2−, ·OH) in blood. Therefore, we hypothesize that alloxan-generated oxygen radicals damage pulmonary capillary endothelial cells, and, possibly, alveolar epithelial cells as well. We examined whether oxygen radical scavengers, such as catalase or dimethylsulfoxide (DMSO), protected against alloxaninduced pulmonary edema.Five dogs in each following group were anesthetized: control group: physiological saline (20ml/kg/h); alloxan group: physiological saline + alloxan (75mg/kg) bolus injection at the beginning of the experiment; catalase group: physiological saline + catalase (150,000u/kg) bolus injection before injection of alloxan; DMSO group: physiological saline + DMSO (0.4mg/kg) bolus injection before alloxan. All dogs had 30-min baseline period and 3-h intervention period. Hemodynamics and circulating substances were measured at the specific points of time. At the end of intervention period, the dogs were killed and had the lungs removed for electron microscopic study and lung water measurement with direct destructive method.
Phagocytosis and hydrogen peroxide production of Eosinophils in the rats spontaneously infected with Mycoplasma pulmonis
Authors: Moriguchi Keiichi , Hirai Kei-Ichi 
Published: June 2020

The ability of hydrogen peroxide (H2O2) production was cytochemically compared in eosinophils (EP) between specific pathogen free (SPF) and spontaneously Mycoplasma pulmonis-infected male rats (Wistar strain).Peritoneal cells including EP (PEP) were harvested with a cold Hanks' balanced salt solution containing 0.1% glucose (HBSSG). Simultaneously, blood granulocytes with eosinophils (BEP) were isolated from the same animals by a Ficoll-Hypaque method. Cells were incubated with latex particles in HBSSG for 60-90 min. Thereafter, cells were washed and transferred into a cerium (Ce) medium consisting of 0.1 M tris - maleate buffer, pH 7.5, 1mM CeCl3, 10 mM sodium azide, 0.1. glucose and 0.25 M sucrose. The incubation was carried out for 20 min at 37°C with occasional stirring. Some cells were incubated for 60 min at 37 °C in a DAB medium containing 0.1% 3.3’-diaminobenzidine 4HCl with particles in 0.1 M phosphate buffer, pH 7.4. All cells were then fixed with glutaraldehyde and osmium tetroxide before processing for electron microscopy, x-ray microanalysis of the subcellular electron-dense reaction deposits was performed under a Tracor-Northern EDX attached to a JEM-1200EX STEM system.
Immunogold localization of calmodulin in root caps of the maize Cultivar Merit
Authors: Nguyen P.T. , Uphoff C. , Stinemetz C.L. 
Published: June 2020

Considerable evidence suggest that the calcium-binding protein calmodulin (CaM) may mediate calcium action and/or transport important in the gravity response of plants. Calmodulin is present in both shoots and roots and is capable of regulating calcium transport in plant vesicles. In roots calmodulin is concentrated in the tip, the gravisensing region of the root; and is reported to be closely associated with amyloplasts, organelles suggested to play a primary role in gravi-perception. Inhibitors of CaM such as chlorpromazine, calmidazolium, and compound 48/80 interfere with the gravitropic response of both snoots and roots. The magnitude of the inhibition corresponded well with the extent to which the drug binds to endogenous CaM. Compound 48/80 and calmidazolium block gravi-induced changes in electrical currents across root tips, a phenomenon thought to be associated with the sensing of the gravity stimulus.In this study, we have investigated the subcellular distribution of CaM in graviresponsive and non-graviresponsive root caps of the maize cultivar Merit.
Some observations on various tissues of mouse with the environmental Scanning Electron Microscopy
Authors: Fujimaki Noboru , Kano Yumiko , Ishikawa Harunori , Ohmori Atsuo , Kawata Shintaro 
Published: June 2020

The environmental scanning electron microscope (ESEM) have recently been developed to permit the observation on wet specimens under environmental gas conditions by improving the differential vacuum system. ESEM has been successfully applied to some fields of material science. However, its application to biological samples is still limited. Hence, we tried to examine the availability of ESEM for the fine structural observation on mammalian soft tissues under saturated water pressure without drying.Adult male DDN mice were used for materials. Fresh tissues without fixation were excised under barbital anesthesia. The tubular viscera were opened and washed with saline after excision and mounted on the ice-chilled specimen holder and examined under ESEM. Internal structures of the parenchymal organs were examined on the exposed surfaces by cutting with razor blades after perfusion fixation with ½ Karnovsky fixative. Some specimens were postfixed with 1 % OsO4. After fixation, the specimens were rinsed with saline and examined under wet condition.
The effect of chemical treatment on thin sections for post-embedding labeling of carbohydrate antigenic sites
Authors: McCaul T. F. , Williams J. C. 
Published: June 2020

Pretreatment of thin sections with Na-m-periodate, an efficient oxidising agent of carbohydrates, has been shown to enhance antigenic recognition by unmasking protein antigenic sites. Such a treatment was not suitable for detecting carbohydrate determinants of phase I lipopolysaccharide (LPS-I) of Coxiella burnetii since the quantity of labelling was reduced. Recent study has demonstrated that immunolabelling of an immunogenic surface protein of similar pathogenic bacterium, C. burnetii, was greatly enhanced after exposure of thin sections at 100°C to a solubilization buffer containing sodium dodecyl sulphate (SDS) and sodium deoxycholate (DOC). In the present study, we report the effect of the solubilization buffer, and proteinase K, which effectively removes peptides and native proteins, on immunolabelling of carbohydrate determinants.C. burnetii (9MIC7), which was purifed from infected yolk sac material of hen eggs by Renografin gradient centrifugation, was fixed for 3 h in 1.5% glutaraldehyde and 0.2% picric acid in 66 mM Na-cacodylate buffer, pH 6.8; pre-embedded in 2% Difco Nobel Agar, and then rinsed once (5 min) in the same buffer. Dehydration was first carried out in 50% methanol (15 min), then in 70% (two changes, 1h each); followed by an intermediate step (66% LR White resin in 70% methanol for 30 min).