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  • 1
    Electronic Resource
    Electronic Resource
    Studies on Feeding and Digestion in Protozoa. VII. Ingestion of Polystyrene Latex Particles and its Early Effect on Acid Phosphatase in Paramecium multimicronucleatum and Tetrahymena pyriformis (1965)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 12 (1965), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Food vacuole-free P. multimicronucleatum and T. pyriformis readily ingest non-nutritive Dow polystyrene latex particles (PLP) and form vacuoles containing PLP at a rate comparable to the formation of vacuoles containing bacteria. The particles aggregate within the vacuoles and are egested as balls of the size of the vacuoles. PLP containing vacuoles rapidly acquire acid phosphatase activity, which is demonstrated by histochemical (alpha-naphthyl phosphatehexazonium salt or lead phosphate) methods as a peripheric staining. The total activity of the cell does not significantly change as a consequence of PLP uptake as suggested by the histochemical preparations and confirmed in T. pyriformis by measuring the splitting of p-nitrophenyl phosphate at pH 5. Accordingly, no selection between nutritive and non-nutritive particles could be revealed. The vacuole formation is induced by the mechanical action of the particles. The appearance of acid phosphatase activity in the vacuole seems to be dependent on the vacuole formation and not on its content. This early appearance of activity is due to a redistribution of the preexistent activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1965.tb01807.x
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  • 2
    Electronic Resource
    Electronic Resource
    The photoreceptors and visual pigments of the garter snake (Thamnophis sirtalis): a microspectrophotometric, scanning electron microscopic and immunocytochemical study (1997)
    Springer
    Journal of comparative physiology 181 (1997), S. 89-101 
    Details
    ISSN: 1432-1351
    Keywords: Key words Reptile ; Photopigments ; MSP ; Immunolabelling ; Vision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Scanning electron microscopy, immunocytochemistry, and single cell microspectrophotometry were employed to characterize the photoreceptors and visual pigments in the retina of the garter snake, Thamnophis sirtalis. The photoreceptor population was found to be comprised entirely of cones, of which four distinct types were identified. About 45.5% of the photoreceptors are double cones consisting of a large principal member joined near the outer segment with a much smaller accessory member. About 40% of the photoreceptors are large single cones, and about 14.5% are small single cones forming two subtypes. The outer segments of the large single cones and both the principal and accessory members of the doubles contain the same visual pigment, one with peak absorbance near 554 nm. The small single cones contain either a visual pigment with peak absorbance near 482 nm or one with peak absorbance near 360 nm. Two classes of small single cones could be distinguished also by immunocytochemistry and scanning electron microscopy. The small single cones with the 360-nm pigment provide the garter snake with selective sensitivity to light in the near ultraviolet region of the spectrum. This ultraviolet sensitivity might be important in localization of pheromone trails.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050096
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  • 3
    Electronic Resource
    Electronic Resource
    Demonstration of Acetylcholinesterase on Motor End-plates after embedding in Polyethylene Glycol (1956)
    [s.l.] : Nature Publishing Group
    Nature 178 (1956), S. 1398-1398 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The histochemical localization of acetylcholin-esterase was studied on the motor end-plates of the guinea pig?s intercostal muscle. Polyethylene glycol embedding was performed by the method of Miles and Linder1, and the Koelle acetylthiocholine iodide method modified by Gerebtzoff2 was used to ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/1781398a0
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  • 4
    Electronic Resource
    Electronic Resource
    The effects of calcium on morphology and histamine content in isolated intact mast cell granules (1978)
    Springer
    Inflammation research 8 (1978), S. 381-381 
    Details
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Conclusion These studies on isolated intact mast cell granules, indicate that changes in the concentration of the divalent cations (Ca2+, Mg2+)alone cannot explain the membrane fusions and histamine release during sequential exocytosis in mast cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01968621
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  • 5
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of Vitamin A in the retina and pineal organ of the frog,Rana esculenta (1988)
    Springer
    Histochemistry and cell biology 88 (1988), S. 533-543 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vitamin A immunoreactive sites were studied in the retina and pincal organ of the frog,Rana esculenta, by the peroxidase antiperoxidase, avidin-biotinperoxidase and immunogold methods. Indark-adapted material, strong immunoreaction was found in the outer and inner segments of the photoreceptor cells of both retina and pineal organ, as well as in the pigment epithelium, retinal Müller cells and pineal ependymal cells. Inlight-adapted retina, cones and green (blue-sensitive) rods were immunopositive. At the electron microscopic level, immunogold particles were found on the membranes of the photoreceptor outer segments as well as on the membranes of the endoplasmic reticulum and mitochondria. Individual retinal photoreceptor cells exhibited strong immunoreaction in the distal portion of the inner segment, the ciliary connecting piece and the electron-dense material covering the outer segment. In the pigment epithelium, the immunolabeling varied in intensity in the basal and apical cytoplasm and phagocytosed outer segments. The immunocytochemical results indicate that retinoids (retinal, retinol and possibly retinoic acid) are present not only in the photoreceptor cells of the retina but also in those of the pineal organ. The light-dependent differences in the immunoreactivity of vitamin A underlines its essential role in the visual cycle of the photopigments. Our results suggest that the pineal ependyma plays a role comparable to that of the Müller cells and pigment epithelium of the retina with regard to the transport and storage of vitamin A. The presence of a retinoid in nuclei, mitochondria and cytoplasmic membranes suggests an additional role of vitamin A in other metabolic processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570321
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  • 6
    Electronic Resource
    Electronic Resource
    Freeze-fracture study of the receptor membranes in the olfactory organ of Alburnus alburnus (Teleostei) (1988)
    Springer
    Zoomorphology 108 (1988), S. 41-46 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Olfactory receptor molecules are assumed to be integral membrane proteins which may be visualized on fracture faces of the membrane as intramembrane particles (IMPs). In the present study, the plasma membrane of the receptor dendrites and ciliated epithelial cells in the teleost fish Alburnus alburnus were studied by freeze-fracture electron microscopy. The IMP diameters on the membrane P-faces of both receptor dendrites and ciliated epithelial cells ranged from 5 nm to 11 nm. The average IMP densities on membrane fracture faces of the ciliated and microvillous sensory dendrites were 3130±780 for the cilia, 2070±550 for the microvilli, 2390±1190 on the knob regions and 3050±1130/μm on the lateral dendrite membranes. The IMP densities on the P fracture faces of the cilia and knob regions were compared with the densities found on the lateral membranes of each individual dendrite. The ratios ranged from 0.5 to 0.96 in the case of the cilia/lateral membrane and from 0.5 to 0.90 in that of the knob/lateral membrane, indicating that, in contrast to the average densities, it is the lateral membrane which has the higher IMP densities and not the cilia. The great variations in the average IMP densities, as well as the considerable variety of the ratios, may be explained by the maturation and turnover of the olfactory sensory neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312213
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  • 7
    Electronic Resource
    Electronic Resource
    Electron microscopy of the paraventricular organ in the sparrow (Passer domesticus) (1967)
    Springer
    Cell & tissue research 80 (1967), S. 229-245 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Characteristics of the ependymal cells of the Paraventricular Organ (PVO) in the sparrow are strongly dilated ergastoplasmic cisternae filled with a moderately dense substance, the absence of cilia and a long basal process ending around capillaries. Elongated cells having a pale cytoplasm (“light cells”) are interposed between the ependymal cells. These cells protrude into the ventricle lumen with a bulbous cytoplasmic swelling; centrioles and several dense-core vesicles occur frequently in them. Two types of nerve cells have been identified in the PVO. The more superficial cells — called type-I neurons have a dendrite-like process which, after passing the ependymal layer reach the ventricle surface and end there freely with a bulbous swelling (“club”). The whole neuron contains dense-core vesicles of an average diameter of 840 Å; the extensive Golgi region is located in the dendrite. The larger type-II neurons situated in the deeper layers show a folded nuclear membrane, large mitochondria and rarely dense-core vesicles; the Golgi apparatus is enclosed in the perikaryon. The nerve cells are embedded in a feltwork of glial and neural processes the latters showing often synaptic (axodendritic) junctions. The majority of the synapses are supposed to occur between the axon-like processes of the typeI neuron and dendrites of the type-II neuron. Axo-somatic synapses can be found not infrequently on the perikarya of the latters. The nature of the free ventricular endings of the neurons and the possible function of the PVO are discussed in the text.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337459
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  • 8
    Electronic Resource
    Electronic Resource
    Elektronenmikroskopische Untersuchungen an den Hüllen des N. ischiadicus der Ratte (1961)
    Springer
    Cell & tissue research 53 (1961), S. 299-312 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Das Perineurium des N. ischiadicus der Ratte ist aus parallelen, aufeinanderliegenden platten Zellschichten aufgebaut, zwischen denen feine Fibrillenschichten eingeschaltet sind. Jede Zellschicht besteht — ähnlich wie ein Plattenepithel — aus stark abgeflachten Zellen (durchschnittliche Dicke etwa 90 mμ), deren beiden freien Oberflächen eine homogene, 18 mμ dicke Basalmembran anliegt. Im Zytoplasma dieser Zellen findet man neben dem Zellkern, den Mitochondrien, dem endoplasmatischen Reticulum und Einschlüssen auch Zeichen einer lebhaften Pinozytose. In den Fibrillenschichten verlaufen, in einer homogenen Grundsubstanz eingebettet, feine Fibrillen in der Längsrichtung des Nerven. Der Zusammenhang zwischen der Feinstruktur des Perineuriums und seiner Rolle als Diffusionsbarriere wird besprochen. Das Epineurium, besonders seine innere dichte Schicht, ist aus längsverlaufenden, kollagenen Fibrillenbündeln zusammengesetzt. Zwischen diesen Bündeln findet man rundliche oder bandförmige Anschnitte von Bindegewebszellen, an deren Oberfläche keine Basalmembran erkannt werden kann.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00338726
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  • 9
    Electronic Resource
    Electronic Resource
    Elektronenmikroskopische Beobachtungen an den Sehzellen des Blutegels, Hirudo medicinalis L. (1964)
    Springer
    Cell & tissue research 63 (1964), S. 618-635 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The visual cell of the leech (Hirudo medicinalis) contains a big vacuole filled with a moderate dense substance (“vitreous body”). The wall of the vacuole consists of a system of microvilli (brush border) merging into the substance of the vitreous body. The cytoplasmic zone underneath the brush border has a special structure consisting of flattened sacs and vesicles giving a radial striation to this cell region. The cytoplasm is filled with a great number of mitochondria and small vesicles. Bundles of fine filaments are striking features of the cytoplasm; in the periphery of the cell they are in close contact with the cell membrane (“half desmosomes”). Elements of the endoplasmic reticulum and free ribosomes may also be present. The cells regularly contain membrane-bounded inclusions having a dense granular or cristalline content. The visual fibers (processes of the visual cells) show a certain similarity to the unmyelinated nerve fibers of higher animals. They are ensheathed into sheath cells possibly of glial nature. Processes of these cells often surround the visual cells and are sometimes embedded in their cytoplasm. Both visual and sheath cells are covered with a homogeneous basement membrane. The possible role of the structures and the problems of conduction from the brush border onto the cell surface are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339910
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  • 10
    Electronic Resource
    Electronic Resource
    Elektronenmikroskopischer nachweis saurer mucopolysaccharide in den flaschenzellen der Xenopus-niere (1970)
    Springer
    Cell & tissue research 104 (1970), S. 56-68 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Xenopus laevis ; Flask cells ; Mucopolysaccharides ; Osmotic stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Flaschenzellen, eigenartige flaschenförmige Epithelzellen im Verbindungsstück der Xenopusniere, enthalten ein stark entwickeltes intrazelluläres Kanalsystem, das mit sauren Mucopolysacchariden gefüllt ist. Bei Anwendung der Methode mit kolloidalem Ferriammoniumglyzerat (pH 1,6) erweisen sich das Material im Kanalsystem, in den Vesikeln in der Nachbarschaft der intrazellulären Kanäle, einige Golgi-Zisternen und Autophagosomen als positiv. Ein dichter Belag von positivem Material wurde auch an der luminalen Oberfläche der Epithelzellen des Verbindungsstückes gefunden. In Fröschen, die monatelang in Salzwasser gehalten wurden, war das intrazelluläre Kanalsystem zurückgebildet. Sein reduzierter Inhalt zeigte eine verminderte Reaktion und im Zytoplasma waren nur ausnahmsweise positiv reagierende Vesikel und Golgi-Zisternen zu beobachten. Wenn die Tiere wieder in Süßwasser gesetzt werden, kommt es zu einer Anhäufung positiver Vesikel und Golgiapparate und einer Zunahme des Materials im Kanalsystem.
    Notes: Summary “Flask cells” (Flaschenzellen), peculiar bottle-shaped epithelial cells in the intermediate segment of the Xenopus nephron, contain a highly developed intracellular channel system filled with acid mucopolysaccharides. The cells were studied with the colloidal ferriammoniumglycerate method at pH 1,6 at the electron microscopic level. The material inside the intracellular channels, cytoplasmic vesicles in the neighbourhood of the latters, several cisternae of the Golgi apparatus and some autophagosomes were found to be positive. A thick coat of positive material was observed also on the luminal surface of the epithelial cells in the intermediate segment. In frogs living in salt water for 2 months, the intracellular channels are strongly under-developed, their reduced content shows a weak reaction; positive vesicles and Golgi cisternae occur exceptionally. If the animals were returned to fresh water, an increase of the reactive vesicles and Golgi cisternae as well as the contents of the channels could be observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00340049
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