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  • Ultrastructure  (10)
  • Springer  (10)
  • Cambridge University Press
  • PANGAEA
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Keywords
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  • Springer  (10)
  • Cambridge University Press
  • PANGAEA
Years
  • 1
    Electronic Resource
    Electronic Resource
    Synaptic morphology of the carotid body of the domestic fowl (1975)
    Springer
    Cell & tissue research 162 (1975), S. 459-473 
    Details
    ISSN: 1432-0878
    Keywords: Carotid body ; Domestic fowl ; Reciprocal synapses ; Afferent axons ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Efferent and reciprocal synapses have been demonstrated in the carotid body of the domestic fowl (Gallus gallus domesticus). Synapses were also found with purely afferent morphology, but were probably components of reciprocal synapses. The general morphology of the endings suggested the presence of two types of axon, afferent axons making reciprocal and perhaps afferent synapses with Type I cells, and efferent axons making efferent synapses with Type I cells. A few axo-dendritic synapses were also found. The dense-cored vesicles associated with the afferent components of reciprocal synapses and with the possible true afferent synapses varied in diameter and core but could belong to one population of presynaptic vesicles. These observations are consistent with a new theory for the carotid body receptor mechanism. This proposes a spontaneously discharging afferent axon inhibited by an inhibitory transmitter substance released by the Type I cell via the “afferent” component of its reciprocal synapse, the “efferent” component inhibiting this release. Besides this chemoreceptor modulation of its afferent axon, the Type I cell may also have a general secretory function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209346
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  • 2
    Electronic Resource
    Electronic Resource
    The general ultrastructure of the carotid body of the domestic fowl (1975)
    Springer
    Cell & tissue research 162 (1975), S. 483-497 
    Details
    ISSN: 1432-0878
    Keywords: Carotid body ; Domestic fowl ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic studies of the carotid body of the domestic fowl (Gallus gallus domesticus) have shown Type I and Type II cells combined with axons into compact groups. The many Type I cells in the depths of the organ had a body, containing the nucleus, and an elongated, flared process. Some of the Type I cells in the superficial regions tended to be spindle-shaped. Type I cells were characterised by membrane-bound, dense-cored vesicles about 120 nm in diameter. Type II cells invested the Type I cells and had axons embedded in them as in Schwann cells. The fine structure of the carotid body in the domestic fowl resembles that of the Lovebird (Uroloncha domestica) and of various amphibia and mammals. The possibility is discussed that the Type I cells may have a chemoreceptor or a general secretory function, or even both pathway for functions together. The main role of the Type II cells seems to be to provide a of these axons leading to or from Type I cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209348
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  • 3
    Electronic Resource
    Electronic Resource
    The structure of the rectal papilla in a parasitoid hymenopteran Nasonia vitripennis (Walker) (Hymenoptera Pteromalidae) (1975)
    Springer
    Cell & tissue research 161 (1975), S. 413-419 
    Details
    ISSN: 1432-0878
    Keywords: Rectal papilla ; Insects ; Hymenoptera ; Cell Types ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the rectal papillae of the parasitoid hymenopteran, Nasonia vitripennis (Walk), is described. These organs in this insect consist of four distinct cell types arranged as a closed, hollow cone. The majority of the cells are present in the raised cone, and are characterised by large numbers of mitochondria arranged in a membranous labyrinth. A series of cells form a collar around the base of the cone. Junction cells have been identified which are present at the point of insertion of the cone into the rectal epithelium. The base of the cone consists of cells with elaborately folded plasma membranes facing both the central cavity of the cone, and the haemolymph. The structure of this rectal papilla is compared with those found in other insects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220008
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  • 4
    Electronic Resource
    Electronic Resource
    The ultrastructure of the mid-gut cells of Nasonia vitripennis (Walker) (Hymenoptera, Pteromalidae) (1977)
    Springer
    Cell & tissue research 177 (1977), S. 227-238 
    Details
    ISSN: 1432-0878
    Keywords: Insects ; Nasonia vitripennis ; Mid-gut ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the mid-gut cells of female Nasonia vitripennis is described. The mid-gut consists of a uniform, single-cell epithelium. The cells of different gut regions were analysed using morphometric techniques in order to determine any differences in the components. The structure of the cells is described in the unfed animal, and after varying periods of feeding on host body-fluids. Tissues were sampled after 12 h and 24 h of feeding on host body-fluids and after 24 h feeding/24 h starvation. The cells were found to be complex and contain an organelle component that allows solute-transport and extensive lipid synthesis. A limited cytochemical analysis involving the lysosomal marker enzyme-acid phosphatase — and the respiratory enzyme — cytochrome oxidase was carried out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221084
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of age on the ultrastructure of the mid-gut cells of the hymenopteran Nasonia vitripennis (Walk.) (Hymenoptera, Pteromalidae) (1977)
    Springer
    Cell & tissue research 177 (1977), S. 239-245 
    Details
    ISSN: 1432-0878
    Keywords: Insects ; Mid-gut ; Aging ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the mid-gut cells of aged female Nasonia vitripennis is described. The mid-gut is a shrunken and distorted organ in the aged animal. The individual cells are highly disorganised and the organelle components are altered. The small lipid droplets formed in the apical cell region do not coalesce to form the large central lipid inclusions characteristic of the young animal. The rough endoplasmic reticulum is reduced and some of the mitochondria enlarge. The mid- and apical cell regions also contain large numbers of cytolysosomes. The basal cell region is essentially unchanged, but the channels formed by the infolded basal plasma membranes are dilated. The changes observed are discussed in relation to previous observations on other insect species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221085
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in nurse and follicle cells during late stages of oogenesis in Drosophila melanogaster (1970)
    Springer
    Cell & tissue research 110 (1970), S. 1-8 
    Details
    ISSN: 1432-0878
    Keywords: Oogenesis ; Drosophila ; Ultrastructure ; Nurse cells ; Follicle cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During stages 11 and 12, follicle cells surrounding the nurse cells produce lysosomes which presumably aid in the breakdown of the nurse cells. Accompanying a DNA reduction in nurse cell nuclei are several characteristic morphological changes including the appearance of intranuclear rod-like structures and nuclear granules about 300 Å in diameter. Similarities between structures seen in Drosophila nurse cell nuclei and those seen in other organisms are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343981
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  • 7
    Electronic Resource
    Electronic Resource
    The ultrastructure of oösorption in Locusta migratoria migratorioides (1972)
    Springer
    Cell & tissue research 135 (1972), S. 275-286 
    Details
    ISSN: 1432-0878
    Keywords: Oöcyte ; Resorption ; Locust ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The changes in the ultrastructure of the oöcyte and associated follicle cells during oösorption in Locusta migratoria migratoroides are described. Throughout the process the follicle cells act in a phagocytic manner and invade the oöplasm. Localizatio of acid phosphatase activity indicates that at the start of resorption the Golgi complexes of the follicle cells begin to produce lysosomes on a large scale, and that these are utilised in the breakdown of yolk spheres which have been taken up from the oöcyte. Partly degraded yolk spheres are collected together along with other cell organelles into cytolysomes. The significance of large numbers of microtubules within the follicle cells and of microvillar borders between the cells in late stage resorbing bodies is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315130
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  • 8
    Electronic Resource
    Electronic Resource
    An efficient procedure for isolation of nuclei from plant protoplasts (1985)
    Springer
    Protoplasma 128 (1985), S. 184-189 
    Details
    ISSN: 1615-6102
    Keywords: Nuclear isolation ; pH ; Protoplasts ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The present communication describes an easy, efficient and rapid method for isolation of nuclei from plant protoplasts. Release of nuclei is accomplished by disruption of protoplasts in an appropriate buffer containing a very low concentration (0.01%) of the detergent Triton X-100. The pH of the nuclei isolation buffer (5.3) played a critical role in the recovery of stable nuclei in large numbers. Supplementation of buffer (10 mM MES) with spermine (0.1 mM), dithiothreitol (2.5 mM), ethylenediaminetetraacetic acid (2.5 mM) and Nad and KCl (10 mM each) improved nuclear yield and quality. With the method developed it is possible to routinely recover 95% nuclei from the protoplasts within 30 minutes. The nuclear preparations are of high purity with little detectable cytoplasmic contamination and no clumping of the nuclei. The structural integrity of the nuclei has been assessed and confirmed by Nomarski differential interference contrast optics and ultrastructural observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276340
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  • 9
    Electronic Resource
    Electronic Resource
    Oögenesis in a marine teleost, Blennius pholis L. (1977)
    Springer
    Cell & tissue research 181 (1977), S. 105-128 
    Details
    ISSN: 1432-0878
    Keywords: Oöcyte ; Oögenesis ; Teleost ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Oögenesis in the oviparous marine teleost, Blennius pholis L., is examined. Eleven developmental stages are identified by ultrastructural observations when changes in the distributions of the organelles and inclusions are described. An exogenous source for the protein yolk precursors is indicated, but less clear is the endogenous contribution. Changes in the follicle epithelium are described together with the formation of the zona which is considered to be follicular in origin. Two types of follicle cell are distinguished and these probably function differently in the process of zona formation. The zona becomes divided into the externa and interna, the latter probably resulting from the chemical ordering by disulphide bonding of the proteinaceous material of the former.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222778
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  • 10
    Electronic Resource
    Electronic Resource
    Ultrastructure of melatonin-responsive cells in the ovine pars tuberalis (1991)
    Springer
    Cell & tissue research 263 (1991), S. 529-534 
    Details
    ISSN: 1432-0878
    Keywords: Melatonin ; Pituitary gland, pars tuberalis ; Secretory cells ; Cyclic AMP ; Ultrastructure ; Cell culture ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Functional receptors for melatonin have been localized and characterized on the pars tuberalis (PT) of a number of mammalian species, but the cell-type responsive to melatonin is unknown. The ultrastructure of the ovine pars tuberalis has been examined and these findings correlated with the functional response of the gland to melatonin. This study revealed that two secretory cell types predominate in the ovine PT, which differ in the abundance of dense-core granules. The most abundant of the cells are either agranular or very sparsely granulated and represent 90% of the total population, with the remaining 10% being composed of cells with abundant dense-core vesicles. Few follicular cells were observed. This ratio of secretory cell-types persisted in primary culture, with the two types non-separable by Percoll gradient centrifugation. Using forskolin, as a non-specific stimulant of adenylate cyclase, melatonin was shown to inhibit the formation of cyclic AMP by 80–90% in cells both before and after Percoll centrifugation. The results demonstrate that the agranular secretory cells of the ovine pars tuberalis are the melatonin responsive cell-type of this gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327285
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