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Atomic Force Microscopy Study Of Fine Structures Of The Entire Surface Of Red Blood Cells, P. -C. Zhang, C. Bai, Y. -M. Huang, H. Zhao, Y. Fang, N. -X. Wang, Q. Li

Scanning Microscopy

Glutaraldehyde-fixed red blood cells were imaged by tapping mode atomic force microscopy (TMAFM) in air at room temperature. The results show that TMAFM can visualize the morphology of the red blood cell at both cellular and nanometer scales. The scan size covers the range from several hundred nanometers to more than one hundred micrometers. TMAFM not only has a higher resolution than the optical microscope, but also can observe biological samples without precoating as required for scanning electron microscopy (SEM). The AFM images of the entire surface of an uncoated red blood cell with nanometer resolution are successfully reconstructed by …

Vascular Architecture Of The Lactating And Non-Lactating Teat Of The Bitch: A Scanning Electron- And Light Microscope Study, F. J. Pérez-Aparicio, V. Dantzer, M. Navarro, A. Carretero, J. Ruberte

Scanning Microscopy

Tissues from fourteen mammary glands of eight bitches were prepared for scanning electron microscopy of vascular corrosion casts and for histology to study the vasculature of the lactating and non-lactating teats. The densely-meshed mammary dermal capillary network formed ridges and troughs. The teat ducts were vascularized by a relatively densely-meshed capillary network which drained into veins longitudinally oriented to the ducts. Between eight and fifteen teat duct openings were seen on the tip of the teat, that were sometimes divided by a septum. The inner vascularization of the teat showed that the main papillary arteries divided into undulating secondary papillary …

Photoemission And Free Electron Laser Spectromicroscopy: Photoemission At High Lateral Resolution, G. Margaritondo

Scanning Microscopy

The move of photoemission analysis from the macroscopic to the microscopic domain has been accelerated by the advent of new ultrabright synchrotron sources of soft-X-rays. This makes an overview of photoemission spectromicroscopy, photoemission at high lateral resolution, quite timely. The overview begins with the basic concepts and problems, both technical and of data-taking strategy. Then, it presents a small number of examples of results in physics and biology, such as local chemical fluctuations in superconductors, semiconductor interfaces and the microchemistry of biological systems. The presentation includes the first experimental results from two new ultrabright synchrotron facilities: ELETTRA (in Italy) and …

Different Approaches To The Study Of Apoptosis, E. Falcieri, L. Stuppia, A. Di Baldassarre, A. R. Mariani, C. Cinti, M. Columbaro, L. Zamai, M. Vitale

Scanning Microscopy

The morphological features of cell undergoing programmed cell death is well known and has been widely described in a number of experimental models with a variety of apoptotic triggering agents. Despite the similar cell behaviour, underlying molecular events seem variable and only partially understood. A multiple approach appears crucial to better clarify the phenomenon. The first technique, DNA gel electrophoresis, allows the identification of fragmented DNA and has been long considered the hallmark of apoptosis. Different patterns of DNA cleavage, which can be identified by conventional or "pulsed-field gel" electrophoresis, are presented and discussed. "In situ" labelling methods are also …

Oxalate-Induced Damage To Renal Tubular Cells, C. R. Scheid, H. K. Koul, L. Kennington, W. A. Hill, J. Luber-Narod, J. Jonassen, T. Honeyman, M. Menon

Scanning Microscopy

Our own studies and those of others have shown that the incidence of calcium oxalate stones and plaques is markedly increased by nephrotoxins. The possible role of oxalate as a nephrotoxin has not been fully appreciated. However, recent studies in experimental animals and in cultured cells support this possibility. The results of these studies led us to hypothesize that hyperoxaluria promotes stone formation in several ways: by providing a substrate for the formation of the most common form of renal stones, calcium oxalate stones, and by inducing damage to renal epithelial cells. Damaged cells in turn would produce an environment …

Synergistic Induction Of The Heat Shock Response In Escherichia Coli By Simultaneous Treatment With Chemical Inducers, T. K. Van Dyk, T. R. Reed, Amy Cheng Vollmer, R. A. Larossa

Biology Faculty Works

No abstract provided.

Transport And Metabolism Of Alanine And Palmitic Acid By Field-Collected Larvae Of Tedania Ignis (Porifera, Demospongiae): Estimated Consequences Of Limited Label Translocation, William B. Jaeckle

Scholarship

The epidermis of larvae of Tedania ignis(Porifera, Demospongiae) is uniformly ciliated except for the posterior pole. The epidermal cells are long, columnar, and monociliate; each cilium arises from an epidermal crypt; symbiotic bacteria were not observed in larval cells. These lecithotrophic ("nonfeeding") larvae can feed by assimilating dissolved organic materials (DOM) from seawater. Larvae transported both the amino acid alanine (mean = 2.73 pmol larva^-1 h^-1; [S] = 1 µM) and the fatty acid palmitic acid (mean = 16.27 pmol larva^-1 h^-1; [S] = 1 µM) from seawater. Following assimilation, the …

In Situ Hybridization And Monoclonal Antibody Analysis Of Plasma Membrane Ca-Pump Mrna And Protein In Submandibular Glands Of Rabbit, Rat And Man, J. L. Borke, A. E. Zaki, D. R. Eisenmann, S. H. Ashrafi, M. M. Sharawy, S. S. Rahman

Scanning Microscopy

The degree of supersaturation of saliva with calcium (Ca) is related to the mineral phase of enamel in erupted teeth, the incidence of caries, and the formation of calculus. The mechanisms for regulating salivary Ca concentration are therefore of relevance to dentistry. Sections of rabbit, rat and human submandibular gland (SMG) were processed for immuno-histochemistry with a specific anti-plasma membrane Ca-pump antibody, 5F10. Western blots confirm that the molecular weight of the proteins identified by our antibody (135 kDa) is consistent with an appropriate molecular weight for PMCA antigen (135-150 kDa). Tissue sections were also processed for in situ hybridization …

Contribution Of Conventional And High Resolution Scanning Electron Microscopy And Cryofracture Technique To The Study Of Cerebellar Synaptic Junctions, Orlando J. Castejón

Scanning Microscopy

The cerebelli of teleost fishes, primates and humans were processed for conventional and high resolution scanning electron microscopy (SEM) to study the outer and inner surfaces of axo-dendritic, glomerular and axo-somatic synapses. The cryofracture technique, either by slow or fast freezing, exposed the hidden neuronal surfaces of synaptic connections, selectively removing the glial ensheathment. Axo-dendritic junctions of climbing fibers and Golgi axonal ramifications were studied in gold-palladium and chromium coated samples. Chromium coating showed different mass density and topographic contrast between axonal and dendritic profiles. Conventional SEM of cryofractured glomerular synapses exhibited the outer surface view of en passant mossy …

X-Irradiation-Induced Disorganization Of Cytoskeletal Filaments And Cell Contacts In Ht29 Cells, Z. Somosy, M. Sass, G. Bognar, J. Kovacs, G. J. Koteles

Scanning Microscopy

Organization of cytoskeleton and cell contacts were studied by immunochemistry and electron microscopy in confluent HT29 cultured cells following exposure to 0.5 and 1.0 Gy doses of X-ray. Microtubules were resistant to irradiation, whereas, the actin and intermediate filaments disrupted rapidly following the treatment and their components appeared as clumps of actin and cytokeratin aggregates in the cytoplasm as demonstrated by immunochemistry. Loss of cell contacts and decrease in the number of desmosomes was also characteristic of irradiated cells. Electron microscopy revealed intact desmosomes in control cells and abnormal desmosomes in the irradiated samples characterized by the absence of tonofilaments. …

A Second Nitrogenase In Vegetative Cells Of A Heterocyst-Forming Cyanobacterium, T Thiel, E Lyons, J Erker, A Ernst

Biology Department Faculty Works

In many filamentous cyanobacteria nitrogen fixation occurs in differentiated cells called heterocysts. Filamentous strains that do not form heterocysts may fix nitrogen in vegetative cells, primarily under anaerobic conditions. We describe here two functional Mo-dependent nitrogenases in a single organism, the cyanobacterium Anabaena variabilis. Using a lacZ reporter with a fluorescent beta-galactoside substrate for in situ localization of gene expression, we have shown that the two clusters of nif genes are expressed independently. One nitrogenase functions only in heterocysts under either aerobic or anaerobic growth conditions, whereas the second nitrogenase functions only under anaerobic conditions in vegetative cells and heterocysts. …

Dental Abnormalities And Early Diagnosis Of Hyperphosphatasemia, M. J. Bottero-Cornillac, A. Gaucher, C. Wang, M. Chaussidon, J. Yvon

Scanning Microscopy

Dental hard tissue abnormalities have never been described as part of the symptoms associated with hyperphosphatasemia. Fourteen teeth obtained from a young man, who had a mild form of hyperphosphatasemia, were analyzed using scanning electron microscopy (SEM), secondary ion mass spectroscopy (SIMS), X-ray diffraction (XRD), and infrared (IR) spectroscopy. SEM revealed a thin enamel, presenting a prismatic structure with many pits, and atypical cementum and dentin showing numerous resorption areas. The X-ray diffractograms revealed poorly crystallinehydroxyapatite associated with α-tricalcium phosphate and magnesium hydroxide phases. SIMS data showed high Ca concentrations: 40.5 weight % {wt%; standard deviation (SD) = 0.13) …

Atomic Force Microscopy Of Nucleoprotein Complexes, Y. L. Lyubchenko, B. L. Jacobs, S. M. Lindsay, A. Stasiak

Scanning Microscopy

Recent data on the AFM studies of nucleoprotein complexes of different types are reviewed in this paper. The first section describes the progress in the sample preparation methods for AFM studies of nucleic acids and nucleoprotein complexes. The second part of this paper reviews AFM data on studies of complexes of DNA with regulatory proteins. These studies include two different types of DNA distortion induced by proteins binding: local bending of DNA at sites of protein binding and formation of large loops due to protein-protein interactions between molecules bound to distant sites along the DNA molecules (DNA looping). The prospects …

Microvascular Corrosion Casting In The Study Of Tumor Vascularity: A Review, M. A. Konerding, A. J. Miodonski, A. Lametschwandtner

Scanning Microscopy

Tumor blood flow is dependent on the structure and three-dimensional (3-D) architecture of the vascular network. The latter can be best studied by scanning electron microscopy of microvascular corrosion casts. However, literature reviews show that nearly all studies using this technique render comparisons of different tumors more difficult since they are mainly based on descriptive terms that might lead to misunderstandings. Qualitative comparisons of 13 experimental and 3 human primary tumors of different origin show a high degree of similarity in the vasculature. Quantitative analysis of these casts reveals similar ranges of parameters such as diameters, intervascular and interbranching distances. …

Thymocyte Proliferation And Apoptosis Induced By Ionizing Radiation, Vera V. Shaposhnikova, Yuri N. Korystov

Scanning Microscopy

Proliferation and apoptosis of rat and mouse thymocytes caused by ionizing radiation were studied. The percentage of proliferating cells was determined by the method of colchicine metaphases and the apoptosis was estimated as DNA fragmentation. In vitro irradiation with 0.05-0.2 Gy was found to stimulate thymocyte proliferation, the maximum was observed at 0.05 Gy for mouse thymocytes and at 0.1 Gy for rat thymocytes. These doses caused a slight decrease in DNA fragmentation, as compared to control. By raising the radiation dose, proliferation was reduced and DNA fragmentation was increased. The results obtained indicate that low radiation doses stimulate cell …

A Reflection Upon The Applicability Of Electron Beam Induced Current (Ebic) As A Sensitive Microanalytical Technique (Ppb Range) For Silicon Materials Research, Martin Kittler, Winfried Seifert

Scanning Microscopy

This paper discusses the application of electron-beam-induced current (EBIC) technique as a tool which is able to provide at least qualitative microanalytical information not available from other techniques. Three examples are given which demonstrate a sensitivity in the parts per billion (ppb) range: temperature dependence of dislocation contrast as a fingerprint of level of metal (Cu) contamination, iron determination down to 1013 atoms per cm3, and visualization of phosphorous striations in silicon grown by float-zone (FZ) method (FZ-grown Si).

Microanalytical information by EBIC is rather indirect and, usually, identification of the impurity species is not possible. Conclusions about impurity content …

Impact Of Escherichia Coli On Urine Citrate And Urease-Induced Crystallization, A. Edin-Liljegren, H. H. Hedelin, L. Grenabo, S. Pettersson

Scanning Microscopy

Escherichia coli (E. coli) is usually not a urease producer. It is, however, often cultured in urinary phosphate containing calculi including ammonium magnesium phosphate stones. This suggests the possibility that E. coli might be involved in stone forming process. The effect of E. coli on urine citrate and urease-induced crystallization in human urine has been studied in vitro. E. coli was found to strongly reduce urine citrate (after 48 hours). In the E. coli inoculated samples, the urease-induced crystallization was increased. There was a strong correlation, r = 0.8, between the citrate decrease and the increase in calcium precipitation. The …

Apoptosis And Calcification, Kookmin M. Kim

Scanning Microscopy

Calcification in necrosis has long been known. Of the tissue components, the cells are most vulnerable. Nevertheless, little attention has been paid to the role of cell death in calcification. This review attempts to update the mechanism of calcification with an emphasis on the role of apoptosis in calcification. A brief review on the basic sciences relevant to calcification is followed by a discussion of abnormal Ca²⁺ and P_i homeostasis in cell injury and apoptosis. Concomitant increases in Ca²⁺ and P_i in blebs (and matrix vesicles) formed by apoptotic and/or necrotic cells are apparently the primary …

Interactions Of Low-Energy Electrons With Atomic And Molecular Solids, Leon Sanche

Scanning Microscopy

Low energy electrons are involved in a large number of analytical techniques for material analysis either as secondary particles or as the primary excitation source. The interaction of these electrons near the surface of solids can be investigated with high-resolution low-energy electron-beam techniques. The results of experiments performed on atomic and molecular solids in the range 0-30 eV with such techniques are reviewed in the present article. The major types of experiments are briefly described and examples of the results obtained from them are given to illustrate the basic mechanisms which control the electron-solid interactions and to provide a description …

Thermal Stability Of Polystyrene Latex Self-Assembled Arrays Studied By Atomic Force Microscopy, Igor Nevernov, Claudio Nicolini

Scanning Microscopy

Preliminary observation of the heat softening of self-assembled polystyrene latex arrays on the submicron scale using atomic force microscopy is reported. Samples of latex self-assembled arrays have been studied in the temperature range from the room temperature up to 120°C. It has been shown that the submicron scale structure remains stable up to the softening point of polystyrene. The experimental set-up used is described and the results obtained are discussed.

Low Temperature Scanning Electron Microscopy Of Clay And Organic Constituents And Their Relevance To Soil Microstructures, C. Chenu, D. Tessier

Scanning Microscopy

Low temperature scanning electron microscopy (LTSEM) is essential for studying the microstructure of small-sized soil constituents such as clays and organic matter. These hydrated and swelling materials naturally undergo drastic changes in water potential and water content in soils. The cryofixation of clays and organic macromolecules by immersion in cryogens and their LTSEM observation are evaluated. The microstructures of clay minerals, polysaccharide macromolecules and their associations, as revealed by LTSEM, contribute to a better understanding of the water retention properties and physical stabilities of these major soil constituents.

Induction Of Crystallization Of Calcium Oxalate Dihydrate In Micellar Solutions Of Anionic Surfactants, H. Füredi-Milhofer, L. Tunik, N. Filipovic-Vincekovic, D. Skrtic, V. Babic-Ivancic, N. Garti

Scanning Microscopy

Calcium oxalate dihydrate (CaC₂O₄.(2+x)H₂O; COD; x ≤ 0.5) does not readily crystallize from electrolytic solutions but appears as a component in crystalluria. In this paper, we review in vitro studies on the factors responsible for its nucleation and growth with special attention given to the role of surfactants. The following surfactants were tested: dodecyl ammonium chloride (cationic), octaethylene monohexadecylether (non-ionic), sodium dodecyl sulfate (SOS, anionic), dioctyl sulphosuccinate (AOT, anionic), and sodium cholate (NaC, anionic). The cationic and some of the anionic surfactants (SOS, AOT) induced different habit modifications of growing calcium oxalate crystals by …

Low Temperature Techniques As A Tool In Plant Pathology, Sigrun Hippe-Sanwald

Scanning Microscopy

In plant pathology, low temperature preparation techniques now appear to be feasible methods to stabilize the dynamic ultrastructure of the host-(plant)-pathogen (fungi) interaction for an analysis by transmission electron microscopy. A well defined ultrastructure of small organisms (fungi) and large biological samples such as plant material and as well as the plant-pathogen (fungus) infection sites are presented. The mesophyll tissue of Arabidopsis thaliana is characterized by homogeneously structured cytoplasm closely attached to the cell wall. Infection sites of stem rust (Puccinia graminis f. sp. tritici) on primary leaves of wheat (Triticum aestivum) and powdery mildew (Erysiphe …

Work Function Dependence Of Charge Transfer In Desorption And Sputtering Of Atoms From Surfaces, Sarah J. Steuber, Peter Nordlander, Hongxiao Shao, David C. Langreth

Scanning Microscopy

Using a recently developed many-electron theory, we investigate the work function dependence of charge transfer during desorption and sputtering of atoms from metal surfaces. We investigate the effects of substrate bandwidth, atomic velocity and level degeneracy on the charge transfer. We show that many-electron interactions introduce relatively small but measurable effects on the work function dependence of the charge transfer. We find that these effects can be stronger for negative ion states than for positive ion states. The reason is that for negative ions, a strongly correlated Kondo state may be formed near the surface.

Endoarticular Loose Bodies And Calcifications Of The Disk Of The Temporomandibular Joint: Morphological Features And Chemical Composition, C. Piacentini, C. Marchetti, A. Callegari, M. Setti, G. Bernasconi, U. Baciliero, P. Menghini, C. Brusotti

Scanning Microscopy

We studied articular disks and endoarticular loose bodies taken from patients suffering from different types of temporomandibular joint (TMJ) pathology. The scanning electron microscopy (SEM) analysis of the disks and the endoarticular loose bodies was followed by a chemical-compositional analysis using an energy dispersive spectrometer (EDS) and by characterization of the crystalline phases by X-ray powder diffraction (XRD). The articular disks were composed of a central radio-opaque area lacking any evident structural features, surrounded by compact bundles of collagen fibers. EDS and XRD analyses showed that endodiscal radio-opaque areas were hydroxyapatite. By SEM, we observed a fibrous network only in …

Atomic Force Microscopy Of Neuron Networks, A. Cricenti, G. De Stasio, R. Generosi, P. Perfetti, M. T. Ciotti, D. Mercanti

Scanning Microscopy

We imaged uncoated neuron networks by an atomic force microscope in the repulsive regime of contact mode. Images of granule cells and their axons have been clearly revealed with details smaller than 20 nm. The good stability of the sample and the mechanical reproducibility of the microscope allowed the imaging of a neuron culture area of several square microns. By combining tens of images, we were able to reconstruct a highly defined neuronal network. Furthermore, the images were very reproducible over repeated scanning acquisition, demonstrating the mechanical and thermal stability of the instrument-sample system.

Human Skin Physiology Studied By Particle Probe Microanalysis, B. Forslind, M. Lindberg, K. G. Malmqvist, J. Pallon, G. M. Roomans, Y. Werner-Linde

Scanning Microscopy

Particle probe methods (electron probe and proton probe X-ray microanalysis) have been applied to investigate the distribution of elements and water over the different layers of the epidermis. For major elements, electron probe X-ray microanalysis (XRMA) provides the advantage of superior spatial resolution, but for trace element analysis the more sensitive proton probe (particle induced X-ray emission, PIXE) analysis has to be used. On a dry weight basis, the concentration of S is rather constant across the epidermis, whereas the concentrations of P, K, Cl and Na show gradients with high levels in stratum germinativum (basale) and stratum spinosum but …

Comparison Of Dna Fragmentation And Color Thresholding For Objective Quantitation Of Apoptotic Cells, D. R. Plymale, D. S. Ng Tang, C. D. Fermin, D. E. Lewis, D. S. Martin, R. F. Garry

Scanning Microscopy

Apoptosis is a process of cell death characterized by distinctive morphological changes and fragmentation of cellular DNA. Using video imaging and color thresholding techniques, we objectively quantitated the number of cultured CD4 + T-lymphoblastoid cells (HUT78 cells, RH9 subclone) displaying morphological signs of apoptosis before and after exposure to γ-irradiation. The numbers of apoptotic cells measured by objective video imaging techniques were compared to numbers of apoptotic cells measured in the same samples by sensitive apoptotic assays that quantitate DNA fragmentation. DNA fragmentation assays gave consistently higher values compared with the video imaging assays that measured morphological changes associated with …

Imaging Of Cherenkov And Transition Radiation From Thin Films And Particles, N. Yamamoto, A. Toda

Scanning Microscopy

Cherenkov radiation and transition radiation, which are generated by high energy electrons with constant velocity, can be detected in a transmission electron microscope using a cathodoluminescence (CL) detection system. The characteristic peaks due to interference were observed in the emission spectra from thin films of mica, silicon and silver, and their dependence on sample thickness and accelerating voltage was studied. Particles of BaTiO3 and MgO also showed characteristic feature in the spectra which changed with their size. A recently developed imaging system revealed the two-dimensional intensity distribution of these radiations; for example, oscillating contrast, such as equal thickness contour appears …

Crystalline Composition Of Equine Urinary Sabulous Deposits, M. Díaz-Espiñeira, E. Escolar, J. Bellanato, J. A. Medina

Scanning Microscopy

The composition and crystal morphology of 141 equine sabulous deposits were determined by infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The IR analysis revealed that all investigated deposits contained calcium carbonates (calcite, CaCO₃, and/or vaterite, CaCO₃) as major constituents; 42 samples were composed of calcite and vaterite, 33 of calcite, 18 of calcite/vaterite and calcium oxalate, and 17 of vaterite. The remaining specimens contained calcite/vaterite and other compounds (calcium phosphates, sulphate and/or oxalates and/or silica). The examination of 44 selected samples by means of SEM/EDX, revealed the characteristic morphology and …