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Electron Microscope Studies (electron + microscope_studies)
Selected AbstractsLight and Electron Microscope Studies on the Nasopharynx and Nasopharyngeal Tonsil of the HorseANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2001P Kumar Light and electron microscope studies were conducted on the nasopharynx and the nasopharyngeal tonsil of 15 young horses. The nasopharynx and nasopharyngeal tonsil was lined with pseudostratified columnar ciliated epithelium and goblet cells. The lymphoepithelium of the nasopharyngeal tonsil was folded forming crypts, the mucosa of which was modified into follicle associated epithelium characterized by stratified cuboidal epithelium, loss of cilia, absence of goblet cells and infiltration of lymphocytes. The lamina propria mucosae of the nasopharyngeal tonsil contained well-developed lymphoid tissue and clusters of seromucus acini. Scanning electron-microscopy revealed a dense mat of cilia covering the nasopharynx and nasopharyngeal tonsil. The follicle-associated epithelium consisted of different populations of microvillus cells in addition to M cells with very short microvilli and a few squamous and intermediate cells. Microvillus cells in the deeper part of the FAE had larger microvilli and their cytoplasm contained a dense population of mitochondria, smooth and rough endoplasmic reticulum, Golgi complexes and lysosomes. The flat surfaced M cell had a more electron-dense cytoplasm and contained small supranuclear vacuoles in addition to the organelles seen in microvillus cells. [source] Late Wisconsinan Port Eliza Cave deposits and their implications for human coastal migration, Vancouver Island, CanadaGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 4 2006M. Al-Suwaidi Sediments of Port Eliza Cave provide a record of the Last Glacial Maximum (LGM) on Vancouver Island that has important implications for human migration along the debated coastal migration route. Lithofacies changes from nonglacial diamict to glacial laminated silt and clay and till, then a return to nonglacial conditions with oxidized clay, colluvial block beds, and speleothems, along with radiocarbon and U/Th dates, define glacial,nonglacial transitions. Scanning electron microscope studies and clay mineralogy confirm that the laminated fines represent glaciation. Preglacial faunal evidence shows a diverse range from small species, including birds, fish, vole, and marmot, to larger species, such as mountain goat. Pollen data from the same unit show a cold, dry tundra environment with sparse trees. Deglaciation occurred prior to an age of 12.3 ka B.P. based on dated mountain goat bone. These data support the viability of the coastal migration route for humans prior to ,16 ka B.P. and then as early as ,13 ka B.P. © 2006 Wiley Periodicals, Inc. [source] Expression of GABAB Receptors in Magnocellular Neurosecretory Cells of Male, Virgin Female and Lactating RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 7 2005D. S. Richards Abstract GABA is one of the key neurotransmitters that regulate the firing activity of neurones in the supraoptic (SON) and paraventricular (PVN) nuclei. In the present study, we used immunohistochemical techniques to study the distribution and subcellular localisation of metabotropic GABAB receptors in magnocellular neurones in the SON and PVN. Robust GABAB receptor immunoreactivity (GABABR; both subunit 1 and subunit 2 of the heterodimer), was observed in the SON and PVN. At the light microcope level, GABABR immonoreactivity displayed a clustered pattern localised both intracytoplasmically and at the plasma membrane. Densitometry analysis indicated that GABABR immunoreactivity was significantly more intense in vasopressin cells than in oxytocin cells, both in male, virgin female and lactating rats, and was denser in males than in virgin females. Light and electron microscope studies indicated that cytoplasmic GABABR was localised in various organelles, including the Golgi, early endosomes and lysosomes, suggesting the cycling of the receptor within the endocytic and trafficking pathways. Some smaller clusters at the level of the cell plasma membrane were apposed to glutamic acid decarboxylase 67 immunoreactive boutons, and appeared to be colocalised with gephyrin, a constituent protein of the postsynaptic density at inhibitory synapses. The presence of GABABR immunoreactivity at synaptic and extrasynaptic sites was supported by electron microscopy. These results provide anatomical evidence for the expression of postsynaptic GABAB receptors in magnocellular neurosecretory cells. [source] A Contribution to the Identity of Rhododendron Powdery Mildew in EuropeJOURNAL OF PHYTOPATHOLOGY, Issue 1 2000A. J. Inman Abstract Rhododendron powdery mildew has caused serious disease on outdoor Rhododendron in Europe since 1981 yet its identity and origins are still uncertain. Light and scanning electron microscope studies continued previous evidence that conidial specimens on outdoor Rhododendron in Europe are morphologically similar. They could all be placed into the newly erected anamorph taxon. Oidium subgenus Pseudoidium. Cleisiothecia of Microsphaera azaleae on deciduous azalea (Rhododendron luteum) and evergreen rhododendron (Rhododendron hybrid and Rhododendron fortunei) are described in detail for the first time in Europe from Bonn, Germany, together with the previously undescribed anamorph. An earlier record of ,M. azaleae' from Belgium was shown to be a new species, here described as Microsphaera digitata sp. nov. The pseudoidium anamorphs associated with both M. azaleae and M. digitata were similar to those examined on outdoor Rhododendron in Europe. They all conformed to the description of Oidium ericinum from Rhododendron and other Ericaceae. These two Microsphaera species are the first rhododendron powdery mildews in Europe for which the teleomorph-anamorph connections have been described. The possible identities of rhododendron powdery mildews in Europe are discussed. Zusammenfassuiig Ein Beitrag zur Identität des Echten Mehltaus an Rhododendron in Europa Seit 1981 ist der Echte Mehllau der Rhododendron cine bedeutende Krankheit an Freiland- Rhododendron in Europa. obwohl dessen Identität und Herkunft noch unsicher ist. Licht-und rasterelektronenmikroskopische Untersuehungen haben frühere Ergebnisse bestätigt,dass es eine morphologischc Similarilät unten den von Freiland- Rhododendron gewonnen Isolaten gibt. Alle Isolate konnten in dem neuen errichtetcn Anamorphe-Taxon Oidium subgenus Pseudoidium zugeordnet werden. Die Kleislothecien von Microsphaera azaleae an Aizaleen (Rhododendron luteum) sowie an immergrünen Rhododendron (Rhododendron-Hybride und Rhododendron fortunei), die in Bonn. Deutschland gesammelt worden waren. werden zum ersten Mai detalliert beschrieben, zusammen mit dem vorher noch nicht beschriebenen Anamorph. Eine frühere Beschreibung von ,M. azaleae' in Belgien konnte als eine neue Art identifiziert werden, hier als Microsphaera digitata sp. nov. beschrieben. Die Pseudoidium-Amimorphe. die mit M. azaleae und M. digitata assoziiert waren. ähnelten den untersuchlen europäischen FrcWand-Rhododendron. Alle konnlen als Oidium ericinum, bekannt von Rhododendron und anderen Ericaceaen. bestimmt werden. Diese Microsphaera -Spezies sind die ersten Echter Mehltau Arten in Europa, wofür die Teleomorph-Anamorph-Vebindungen beschrieben worden sind. Diskuticrt werden auch die möglichen Identilälen von den Echter Mehllau Arten in Europa. [source] Magnetite in ALH 84001: An origin by shock-induced thermal decomposition of iron carbonateMETEORITICS & PLANETARY SCIENCE, Issue 6 2003Adrian J. BREARLEY Transmission electron microscope studies of carbonate fragments embedded within feldspathic glass show that the fragments contain myriad, nanometer-sized magnetite particles with cuboid, irregular, and teardrop morphologies, frequently associated with voids. The fragments of carbonate must have been incorporated into the melt at temperatures of ,900°C, well above the upper thermal stability of siderite (FeCO3), which decomposes to produce magnetite and CO2 below ,450°C. These observations suggest that most, if not all, of the fine-grained magnetite associated with Fe-bearing carbonate in ALH 84001 could have been formed as result of the thermal decomposition of the siderite (FeCO3) component of the carbonate and is not due to biological activity. [source] Light and Electron Microscope Studies on the Nasopharynx and Nasopharyngeal Tonsil of the HorseANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2001P Kumar Light and electron microscope studies were conducted on the nasopharynx and the nasopharyngeal tonsil of 15 young horses. The nasopharynx and nasopharyngeal tonsil was lined with pseudostratified columnar ciliated epithelium and goblet cells. The lymphoepithelium of the nasopharyngeal tonsil was folded forming crypts, the mucosa of which was modified into follicle associated epithelium characterized by stratified cuboidal epithelium, loss of cilia, absence of goblet cells and infiltration of lymphocytes. The lamina propria mucosae of the nasopharyngeal tonsil contained well-developed lymphoid tissue and clusters of seromucus acini. Scanning electron-microscopy revealed a dense mat of cilia covering the nasopharynx and nasopharyngeal tonsil. The follicle-associated epithelium consisted of different populations of microvillus cells in addition to M cells with very short microvilli and a few squamous and intermediate cells. Microvillus cells in the deeper part of the FAE had larger microvilli and their cytoplasm contained a dense population of mitochondria, smooth and rough endoplasmic reticulum, Golgi complexes and lysosomes. The flat surfaced M cell had a more electron-dense cytoplasm and contained small supranuclear vacuoles in addition to the organelles seen in microvillus cells. [source] | ||||||||||