Biology Commons^™

Beam Sensitivity Of Globoid Crystals Within Seed Protein Bodies And Commercially Prepared Phytates During X-Ray Microanalysis, Irene Ockenden, John N. A. Lott

Scanning Microscopy

Magnesium, potassium, calcium and phosphorus are stored in seed tissues in spherical particles called globoid crystals. The main component of globoid crystals is phytin, a salt of myo-inositol hexaphosphoric acid. Based on chemical similarity, commercially available phytates may be suitable standards for quantitative energy dispersive X-ray (EDX) microanalysis of globoid crystals. The stability of globoid crystals and commercial phytates was different when analyzed under identical conditions. Phytates in globoid crystals from Cucurbita maxima cotyledons, were relatively stable in the electron beam during EDX microanalysis at room temperature, but there was a loss of potassium. No loss of potassium occurred during …

The Vestibular Epithelia In Experimental Hydrops, K. C. Horner, S. Rydmarker

Scanning Microscopy

Morpho-pathological features, observed by scanning electron microscopy, in guinea pigs with endolymphatic hydrops of 4-14 months included shortening of the hair cell tufts, loss of tufts, retraction of sensory hair cells away from the surrounding tissue and hair cell loss. After 22 months of hydrops, there was complete loss of hair cells with indifferentiation of the epithelium. The loss of ciliary tufts involved loss of both stereocilia and kinocilia identified as short stubs and holes respectively. Control macular epithelia showed no hair tuft loss although ampullae in control ears could show some loss.

Retention Of Calcium Oxalate Crystals In Renal Tubules, Saeed R. Khan, Raymond L. Hackett

Scanning Microscopy

Crystal retention within the renal tubules is essential for nephrolithiasis and the development of urinary stone disease. We studied the mechanisms involved in this process by inducing calcium oxalate crystal deposition within the rat renal tubules and examining them using various microscopic techniques. Crystals appeared to be retained either by attachment to the tubular epithelium or by aggregating with other crystals thus becoming large enough to be retained by their collective size.

Morphological Study Of Calcospherites In Rat And Rabbit Incisor Dentin, H. Mishima, T. Sakae, Y. Kozawa

Scanning Microscopy

Calcospherites from incisors of rats and rabbits were studied, by means of secondary and backscattered electron images, using scanning electron microscopy. Part of each incisor specimen was made anorganic to allow observation of the surface of the mineralization front by scanning electron microscopy; the other part was ground on one side for observation by scanning electron microscopy with a backscattered electron image detector. In both species the labial mineralization front was wavy and the image showed fused calcospherites, whereas the lingual mineralization front appeared to consist of a combination of linear and globular forms. In rat labial dentin the calcospherites …

Seed Coat Surface Patterns And Structures Of Oxytropis Riparia, Oxytropis Campestris, Medicago Sativa, And Astragalus Cicer, D. J. Solum, R. H. Lockerman

Scanning Microscopy

Scanning electron microscopy was used to examine external and internal seed coat structures of Oxytropis riparia Litv., Oxytropis campestris L., Medicago sativa L., and Astragalus cicer L. for characteristics useful in taxonomic classification and to identify hard seed coat components which affect permeability. Seed coat surfaces of the four species were distinctly different. Palisade and hourglass cell lengths and parenchyma and endosperm cell layer thicknesses were similar among species with the exception of O. campestris seeds which lacked an identifiable endosperm layer. Surface pattern differences and the presence of a distinct endosperm layer are useful in separating these genera and …

Scanning Electron Microscopy Of Corrosion Casting In Medicine, M. A. Konerding

Scanning Microscopy

The aims of this review are: 1. to provide a bibliography of the publications that have used the corrosion casting technique; 2. to describe the advantages and limitations of the methodology; 3. to illustrate possible applications in the field of medicine, and 4. to highlight the significance of this method in the teaching of medical students. Thus, this paper is primarily focused on the scanning electron microscopical examination of vascular corrosion casts.

The unsurpassed three-dimensionality of the corrosion casting technique compared to any other means stands out in particular. This can be especially useful when complex vascular-anatomical relationships are present. …

A Technique For Correlative Scanning And Transmission Electron Microscopy Of Individual Human Placental Villi: An Example Demonstrating Syncytial Sprouts In Early Gestation, G. J. Burton, K. W. Thurley, J. N. Skepper

Scanning Microscopy

Correlating the surface appearances of certain features with their internal structure is made particularly difficult in the human placenta by the complex three-dimensional branching pattern of the villous tree. This places a possible limitation on the use of the scanning electron microscope in this field, both for basic research purposes and as a tool in pathological diagnosis. To help overcome this problem, a technique for handling individual placental villi has been devised. By attaching single villi to glass pipette tips it has proved possible to scan the villi, embed them in resin and then section them in a known pre-determined …

Preparation Of Inner Ear Sensory Hair Bundles For High Resolution Scanning Electron Microscopy, M. P. Osborne, S. D. Comis

Scanning Microscopy

Chemical fixation techniques for preservation of sensory hair bundles in the mammalian inner ear for scanning electron microscopy (SEM) are reviewed. Fixatives employed were glutaraldehyde, glutaraldehyde-picrate, glutaraldehyde-tannic acid, glutaraldehyde-formaldehyde, glutaraldehyde followed by postfixation with osmium tetroxide and the osmium thiocarbohydrazide (OTOTO) method. Dehydration was routinely accomplished with ascending grades of acetone followed by critical point drying with liquid CO₂ or fluorocarbon sublimation. Specimens other than those prepared by the OTOTO method were metal coated with gold, gold-palladium or platinum. Material was viewed at high resolution (2-3 nm) in a transmission electron microscope (TEM) fitted with a scanning system and …

Thin Sectioning Of Carbonaceous Adsorbent Spheres For Visualization By Light Microscopy And Scanning Electron Microscopy, Samuel H. Cohen, Ronald A. Segars

Scanning Microscopy

Three different types of Rohm and Haas carbonaceous adsorbent spheres (XE-340, XE-347 and XE-348) were prepared for light and scanning electron microscopy by embedding in resin and by thin sectioning. Spurr's low viscosity resin, because of its penetrating and wetting ability, contributed to the production of the most uniform and artifact free thin sections. In addition to thin sectioning, gas adsorption surface area measurements were made on batches of each type of sphere.

There was an apparent relationship between the surface area measurements of 417.8 m²/g for XE-340, 583.4 m²/g for XE-347 and 752.9 m^{2 …}

Scanning Electron Microscopic Analysis Of Dental Wear On The Heavily Worn Second Molars Of The Wild Japanese Monkey (Macaca Fuscata), Teruyuki Hojo

Scanning Microscopy

Microscopic features on scanning electron micro-graphs of epoxy-replicas of the second molars of nine wild-caught adult female Japanese monkeys, Macaca fuscata, from Oita Takasakiyama, Kyushu, were measured using a digitizer. These monkeys had been fed a monkey-diet during three or four days of captivity before replicas were made. Six of these specimens showed such heavily worn second molars that narrow peripheral enamel bands surrounded large dentin exposures and the cusps of the others had been worn off. Microwear measurements from sites near facet 9 were compared with those of facet 9 of three kinds of hard-object feeding primates from …

Elemental Mapping Of Cryosections From Cnidarian Nematocytes, Karl Zierold, Pierre Tardent, Sergey V. Buravkov

Scanning Microscopy

The distribution of elements in stinging capsules containing cells called nematocytes is shown by pseudocoloured maps representing the X-ray intensity collected from freeze-dried cryosections. This method provides a distinct overview in addition to the quantitative evaluation of single X-ray spectra. Selected examples illustrate the elemental compartmentation in various cnidarian animals. In particular the matrix of capsules in Hydra vulgaris contains high amounts of K in comparison to the tubule, the surrounding capsule wall and the cytoplasm, whereas in Actinia eguina capsules have either high concentration of Ca or Mg, the latter accompanied by S.

Backscattered Electron Imaging For High Resolution Surface Scanning Electron Microscopy With A New Type Yag-Detector, Paul Walther, Rudolf Autrata, Ya Chen, James B. Pawley

Scanning Microscopy

Double Layer Coating for backscattered electron imaging is a coating and imaging method especially suitable for high resolution scanning electron microscopy (SEM) of large biological samples. Since the backscattered electron (BSE) signal from thin metal coating layers is quite low, field emission SEM's and very sensitive BSE-detectors are required for this method. In this study an improved BSE-detector of the YAG type was used with an in-lens type field emission SEM. Two samples were investigated in order to demonstrate and to improve the potential of this new approach: (1) cryo-prepared cultured kidney cells were shadowed by electron beam evaporation with …

The Study Of The Surface Geometry Of Renal Stone Fragments After Shock Wave And Ultrasound Disintegration, Roch Thibert, Rashad Tawashi

Scanning Microscopy

Computerized image analysis was used for characterizing the irregular boundaries of calcium oxalate stone fragments resulting from shock wave and ultrasound disintegration. The complexity of the contour of the fragments was determined to evaluate the surface roughness of the rugged profile of the samples. Crack propagation on the crystal surface of the mineral phase was studied using fractal geometry. A significant difference was observed in the boundary variation of the calcium oxalate stone fragments treated by shock wave and ultrasound. Crack propagation in the mineral phase crystal was found to depend on the method of fragmentation used. There is also …

Scanning Tunneling Microscopy Imaging Of Synthetic Oligonucleotides And Oligonucleotide-Metal Complexes, Yun Kim, Charles M. Lieber

Scanning Microscopy

Scanning tunneling microscopy (STM) has been used to image 12-and 24-base pair (bp) synthetic oligonucleotide duplexes alone or with intercalatively-bound metal complexes with submolecular resolution. The sizes of the 12-and 24-bp oligonucleotides determined from STM images are close to expected values, and images of isolated duplexes resolve the two nucleotide strands of these molecules. The variation of duplex size in our images demonstrates that these features are not due to surface artifacts. In addition, images of the 12-bp duplex in the presence of bis(9, 10-phenanthrenequinone diimine)(2, 2'-bipyridyl) rhodium(III) exhibit a new structural feature at 14 ± 2 Å from the …

Error Voltage Components In Quantitative Voltage Contrast Measurement Systems, D. S. H. Chan, T. S. Low, J. C. H. Phang

Scanning Microscopy

This paper presents the results of computer simulation studies into the respective contributions of the potential barrier, the off-normal incidence injection of secondary electrons (SEs) into the retarding field and analyser geometry on Types I and II local field error voltages for a practical 20 mm wide planar retarding field energy analyser. Results show that the error voltage component due to the off-normal incidence injection effect of SEs into the retarding field dominates the Type I local field error. For type II LFE, the error voltage component due to analyser geometry effect is the higher contributing factor. The presence of …

The Hepatic Microcirculation In Experimental Cirrhosis A Scanning Electron Microscopy Study Of Microcorrosion Casts, E. Gaudio, L. Pannarale, M. Ripani, P. Onori, O. Riggio

Scanning Microscopy

The experimental model of liver cirrhosis induced by intragastric administration of CCl₄ reproduces not only the histological picture of the postnecrotic cirrhosis but also its pathophysiological features.

Corrosion casts of livers affected by CCl₄-induced cirrhosis show the loss of the lobular pattern. Once the cirrhosis has completely developed, the whole microvascular bed appears to be composed of groups of sinusoid nodules of diameters varying between 0.3 and 1.5 mm.. Pre- and post-sinusoidal vessels and anastomoses between the former and the latter are mainly located at the perinodular spaces.

This microvascular situation modifies the normal perfusion gradient within …

Restricted Energy Transfer In Laser Desorption Of High Molecular Weight Biomolecules, Akos Vertes, Renaat Gijbels

Scanning Microscopy

Producing ions from large molecules is of distinguished importance in mass spectrometry. In our present study we survey different laser desorption methods in view of their virtues and drawbacks in volatilization and ion generation. Laser induced thermal desorption and matrix assisted laser desorption are assessed with special emphasis to the recent breakthrough in the field (m/z > 100,000 ions produced by matrix assisted laser desorption). Efforts to understand and describe laser desorption and ionization are also reported. We emphasize the role of restricted energy transfer pathways as a possible explanation to the volatilization of non-degraded large molecules.

Retinal Changes In A Mutant Form Of Goldfish With Megalophthalmia, David T. Yew, Winnie W. Y. Li, C. Au, H. L. Choi, Q. D. Yang, Patrick K. H. Chan

Scanning Microscopy

The retinal changes of a mutant strain of goldfish with megalophthalmia were studied by histology, electron microscopy and biochemistry. Changes in the morphology of the pigment epithelium, decrease in number of photoreceptors, thinning out of retinal layers and the existence of spaces in the retina were all features as the eyes grew in size. Invasion of macrophages was also evident in the retina. A decrease in leucine uptake per milligram of retina was also detected as the eye grew beyond 0.8 millilitre in volume. These changes, although related to volume changes (i.e., growth) of the eyes, were found to have …

The Primary Energy Dependence Of Backscattered Electron Images Up To 100 Kev, I. Geuens, B. Nys, J. Naudts, R. Gijbels, W. Jacob, P. Van Espen

Scanning Microscopy

The backscattered electron coefficient is known to be primarily dependent on the atomic number of the sample. If the atomic number increases, the backscattered electron coefficient increases, which results in a higher intensity in the backscattered electron image. The dependence of the primary electron energy is somewhat more complicated. Using photographic material (with composition AgBr-AgI), it is seen that the contrast in the backscattered electron image increases with the primary electron energy. Using three independent methods, based on image analysis techniques, it is shown that the difference between the backscattered electron coefficient of AgBr and AgI increases with the primary …

Theodore Alvin Hall: A Biographical Sketch And Personal Appreciation, Brij L. Gupta

Scanning Microscopy

As the first in a series of two papers contributed on the occasion of a special program held at the Scanning Microscopy/1989 meeting in Salt Lake City in honour of Dr. T.A. Hall, and in recognition of his achievements for biological electron probe X-ray microanalysis, this paper provides a biographical sketch of Dr. Hall, as well as a bibliography.

Growing And In-Situ Processing Of Cells On Beem Capsule Caps For Scanning Electron Microscopy, Eugene F. Bernard, Tatsuo Hase

Scanning Microscopy

A simple technique for processing cells grown on BEEM capsule caps for scanning electron microscopic (SEM) observation is described. The cells adhere to a substratum on the inner surface of caps coated with either an egg white-polyvinylpyrrolidone solution or a polylysine solution in the case of eukaryotic cells and an agar solution in the case of bacteria. The adhering cells are cultured and then processed in situ for SEM observation. Electron micrographs revealed details of the shape of the cells growing on the surface of the substrate. The technique seems to be particularly well suited for observing sequential morphological changes …

Ultrastructure Of Coronary Arterial Endothelium In Atherosclerotic Swine Suggests Lipid Retro-Endocytosis, Keith A. Robinson, Robert P. Apkarian

Scanning Microscopy

During experimental atherosclerosis, arterial endothelial cells show characteristic ultrastructural changes including the appearance of increased numbers of plasmalemmal and cytoplasmic vesicles. These structures have been shown by tracer studies to participate in the transcellular transport of low-density lipoprotein cholesterol and β-very-low-density lipoprotein cholesterol from the arterial lumen into the abluminal extracellular matrix. Although this probably represents the major lipid transport pathway, other forms of transport may exist. We document the presence of apparent lipid structures averaging approximately 300 nm in diameter at or near the luminal surface of coronary arterial endothelium of atherosclerotic miniature swine. The structures exhibited a particulate …

Scanning Electron Microscopy Of The Forming Enamel Of Rat Incisor: Influence Of Fixative And Treatments Interacting With The Organic Matrix, J. P. Salomon, J. M. Legrand, M. Goldberg

Scanning Microscopy

The forming enamel of rat incisor was either treated before fixation with one of these five treatments: ultrasonication, NaOCl, chloroform/methanol, NaOH or tween 20; or the incisors were first fixed and then submitted to one of these treatments. The structure of the forming enamel, compared with sections fixed with aldehyde and submitted to osmic maceration, depends on the way the samples were treated and on the fixative used. An amorphous material, removed by osmium tetroxide but not by aldehyde solution was seen to be located between fiber-like structures. In the region of inner enamel secretion the thickness of interrod septa …

Ted Hall And The Science Of Biological Microprobe X-Ray Analysis: A Historical Perspective Of Methodology And Biological Dividends, Brij L. Gupta

Scanning Microscopy

This review surveys the emergence of electron probe X-ray microanalysis as a quantitative method for measuring the chemical elements in situ. The extension of the method to the biological sciences under the influence of Ted Hall is reviewed. Some classical experiments by Hall and his colleagues in Cambridge, UK, previously unpublished, are described; as are some of the earliest quantitative results from the cryo-sections obtained in Cambridge and elsewhere. The progress of the methodology is critically evaluated from the earliest starts to the present state of the art. Particular attention has been focused on the application of the method in …

Three-Dimensional Morphological Analysis Of Nerve Cells By Scanning Electron Microscopy. A Review, O. J. Castejón

Scanning Microscopy

The present review provides a rational and new approach to study the three-dimensional morphology of nerve cells in situ at both cellular and macromolecular levels, by means of conventional (SEM) and high resolution scanning electron microscopy (HRSEM). The slicing and ethanol-cryofracturing methods, the freeze-fracture SEM method and tissue preparation for HRSEM have been described. Nerve cell outer surface, axon hillock and initial axon segment, axonal collateral ramifications and dendritic processes were visualized either by the slicing technique or the cryofracture method displaying neuronal geometry in situ. The cleavage plane occurred at the satellite neuroglial sheath exposing somatic hidden surfaces of …

Microvillus Form Of Focal Anchorage In Human Chang Liver Cells Rounded By Antiporter Activation: Scanning Electron Microscopy Profiles And Evidence Of Traction Origin, K. H. Sit, B. H. Bay, K. P. Wong

Scanning Microscopy

Na⁺/H⁺ anti porter activation in human Chang liver cells produces a flat-to-round (FTR) change in cell shape with gross reduction in cell profile area. Scanning electron microscopy (SEM) vividly displays a third phenomenon, viz., the development of focal microvillus anchors. Reduction in cell profile area concomitant with the development of this microvillus form of focal anchorage is quantitated by on-line image analysis during SEM examination. The reduction in profile area is corroborated by spectrophotometric digitization in light microscopy. Transmission electron microscopy (TEM) of rounded cells shows large endocytic channels and endosomes consistent with the observation of internalization …

Fluorescence Recovery After Photobleaching Techniques To Measure Translational Mobility In Microscopic Samples, Ken Jacobson, Fen Zhang, Tsong-Tseh Tsay

Scanning Microscopy

The scope of photobleaching applications and the method itself are briefly reviewed. Two current applications in this laboratory are then outlined. First, the use of spatial Fourier transforms to analyze video photobleaching measurements is presented. This method extracts diffusion coefficients using all the image data and it does not require that the initial condition created by photobleaching be known. Second, the use of genetic engineering methods coupled with photobleaching analysis is discussed as means to uncover the structural determinants of membrane protein lateral mobility.

Three-Dimensional Morphology Of Cerebellar Protoplasmic Islands And Proteoglycan Content Of Mossy Fiber Glomerulus: A Scanning And Transmission Electron Microscope Study, O. J. Castejón, H. V. Castejón

Scanning Microscopy

The present review summarizes the outer and inner surface features of mossy fiber glomeruli in vertebrate cerebellar granular layer as seen by conventional scanning electron microscopy (SEM) and SEM freeze-fracture method. The intracortical trajectory of mossy fibers and their synaptic contacts with granule cell dendrites were traced by the slicing and freeze-fracture techniques revealing the radial distribution of granule cell dendrites around the central mossy rosette. The "en passant" nature of mossy fiber synaptic contacts and the participation of Golgi cell axonal ramifications were demonstrated. The results obtained were compared with available light and transmission electron microscopy data. The freeze-etching …

Alpha-Particle Irradiation-Induced Change In Bronchopulmonary Macrophage Morphology, In Vitro, T. M. Seed, G. K. Niiro

Scanning Microscopy

Bronchopulmonary macrophages, isolated from canine lungs by saline lavage and grown in tissue culture for short periods, were acutely irradiated with a range of doses of either Americium-241 alpha particles (0.03-48 Gy) or 250 keV x-rays (0.5-24 Gy). Following a 24-hour reincubation and "expression" period, cells were examined for radiation-induced changes in overall viability, as well as in cell morphology and ultrastructure. Results indicated that neither quality of radiation had much effect on cell viability over dose ranges examined, but substantial changes in cell volume, surface topography, and cytoplasmic features were noted, especially in the alpha-particle-irradiated specimens. Results support the …

A Scanning Electron Microscopic Morphological And Semi-Quantitative Evaluation Of Rat Stomach Treated With Colloidal Bismuth Subcitrate And Alcohol, C. Winters, S. M. Hinsull, Z. Gregory

Scanning Microscopy

Scanning electron microscopy was utilised to study the effect of absolute alcohol on the normal morphology of the rat stomach, together with the gastroprotective actions of colloidal bismuth subcitrate. Studies on normal gastric morphology revealed that the major portion of the stomach was covered by a protective coating of mucus. However, there was considerable variation in the integrity of the mucosal surface of the control animals, with the loss of surface epithelial cells in some regions which may account for the variation in response to necrotising agents. The long-term administration of the gastrocytoprotective agent colloidal bismuth subcitrate resulted in a …