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  • Articles: DFG German National Licenses  (11)
  • Electronic Resource  (11)
  • 1980-1984  (11)
  • Cell & Developmental Biology  (11)
  • 1
    Electronic Resource
    Electronic Resource
    Establishment of the site of involution at novel locations on the amphibian embryo (1981)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 169 (1981), S. 149-159 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anuran (Rana) and urodele (Ambystoma) amphibian eggs were subjected to prolonged unnatural orientations in relation to gravity. In some cases eggs were rotated 90°, while in other instances eggs were rotated 180° (complete inversion). Alterations in the pigmentation pattern, cleavage pattern, and site of involution were observed. Despite these unnatural orientations to gravity, the morphogenesis of axial structures was frequently normal. Reorganization of the egg cytoplasm apparently takes place after the unnatural orientation. Rather than being localized in a fixed position in the egg (e.g., the egg cortex), the determinants for the pattern of early embryogenesis are probably located in that portion of the cytoplasm (e.g., “internal” cytoplasm) that orients to gravity.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051690203
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Cytodiffrentiation in the accessory glands of Tenebrio molitor. VI. A congruent map of cells and their secretions in the layered elastic product of the male bean-shaped gland (1980)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 166 (1980), S. 289-322 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of the bean-shaped accessory glands (BAGs) of males of Tenebrio molitor is described. All cells in the secretory epithelium are long and narrow (300-400 mμ × 5 mμ). The seven types of secretory cells are distinguished from one another by the morphology of their secretory granules. Granule substructure varies from simple spheres with homogeneous electrondense contents to complex forms with thickened exterior walls or with crystalline and membranous contents. Individual cell types were mapped by staining whole glands with Oil Red O, and the cell distributions were confirmed by wax histology and ultramicroscopy. The secretions of all seven cell types form a secretory plug composed of seven layers. During mating, the secretory plug from each BAG is forced into the ejaculatory duct by contractions of a sheath of circular muscle. The mirror image plugs from symmetrical BAGs fuse and are transformed into the wall of the spermatophore.
    Additional Material: 69 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051660304
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Morphology of the aedeagal gland of the male mealworm beetle (Tenebrio molitor L.) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 259-281 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The aedeagal gland of male Tenebrio molitor consists of numerous acini containing several secretory units (organules) of three epithelial cells in series. The distal cortical cell and intermediate cell are secretory cells. Secretory products are passed into microvilli-lined extracellular reservoirs. From these storage areas products flow through minute canaliculi and into the efferent ductule. Canaliculi, cuticular trabeculae, and fibrillar material are characteristic features of the efferent ductules within the extracellular reservoirs of secretory cells. After passing from the secretory cells, the efferent ductule penetrates the basal ductule cell. The thin epicuticle that comprises the wall of the ductule is confluent with the epicuticle of the cuticular sheath forming the wall of the genital pocket. Secretory products flow from the cortical cell ductule into the intermediate cell and eventually empty into the genital pocket. A chemical reaction apparently takes place in the intermediate cell ductule, resulting in a frothy secretion product. When released from the ductule, this frothy product forms a foam-like layer that coats the inner wall of the genital pocket. Ultrastructural and probable functional aspects of this gland are described and discussed.
    Additional Material: 30 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051710303
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Cytodifferentiation in the accessory glands of Tenebrio molitor. X. Ultrastructure of the tubular gland in the male pupa (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 97-112 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The tubular accessory gland consists of a simple secretory epithelium surrounded by a muscular coat. Over the pupal instar, the gland increases ten-fold in volume and 15-fold in length. Pupal development is divisible into a phase of mitosis and one of cell growth. During the mitotic phase, cytoplasmic membranes are sparse and nuclei move toward the luminal face of the epithelium to undergo division. In the cell growth phase, the cells become more columnar, a few stacks of rough endoplasmic reticulum are formed, and small dense secretory vesicles appear near the apical surface. The hormonal control of the developmental sequence is discussed.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051720109
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  • 5
    Electronic Resource
    Electronic Resource
    Cytodifferentiation in the accessory glands of Tenebrio molitor. XI. Transitional cell types during establishment of pattern (1983)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 178 (1983), S. 139-154 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The bean-shaped accessory glands of male Tenebrio consist of a single-layered epithelium which is surrounded by a muscular coat. The epithelial layer, which produces precursors of the wall of the spermatophore, contains eight secretory cell types. Each secretory cell type is in one or more homogenous patches, and discharges granules which form one layer of the eight-layered secretory plug. Maturation begins in cell types 4, 7, and 6 on the last pupal day. A newly identified cell (type 8) in the posterolateral epithelium matures last. Cells of individual types mature in synchrony, and their secretory granules “ripen” in a sequence that is characteristic for each type. As the secretory cells of each patch mature, unusual short-lived cells appear at interfaces between patches. In some cases the secretory granules in these boundary cells have ultrastructural features which are mixtures of the definitive characteristics of granules in adjacent cell types. The transitional cell types disappear at 3-4 days after eclosion. Intermediate cell types are absent in the mature gland and boundaries between the patches are distinct. The transitional cells may form granules of intermediate structural characteristics as a dual response to cellular interaction with adjacent and previously differentiated secretory cells.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051780206
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  • 6
    Electronic Resource
    Electronic Resource
    On the activity and fidelity of chromatin-associated hepatic DNA polymerase-β in aging murine species of different life spans (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 106 (1981), S. 435-444 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Activity and accuracy of chromatin-directed DNA replication have been compared in young and aged Mus musculus and Peromyscus leucopus, two murine species with contrasting maximum lifespans. Chromatin isolated from livers of mature adults of both species copied efficiently exogenous DNA templates using predominantly DNA polymerase-β. The DNA synthetic activity of liver chromatin remained constant in both species throughout their lifetimes. The fidelity of chromatin-directed poly [d(A-T)] synthesis was similar for the comparatively short-lived M. musculus and the relatively long-lived P. leucopus and remained unaltered in old animals. The fidelity of poly [d(A-T)] copying catalyzed by DNA polymerase-β dissociated from liver chromatin was comparable to that of the chromatin-directed synthesis. The dissociated enzymes did not exhibit diminished fidelity of poly [d(A-T)] synthesis with age. In all ages of both species examined, the murine liver DNA polymerase-β, both chromatin-associated and solubilized, exhibited high error frequencies; approximately one dGMP was incorporated for every 500-1,000 complementary nucleotides polymerized. The relationship of these results to the accuracy of DNA replication and repair as a determinant of aging is considered.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041060313
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    A cloning assay for 6-thioguanine resistance provides evidence against certain somatic mutational theories of aging (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 121 (1984), S. 309-315 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The frequencies of 6-thioguanine-resistant primary clones from the kidneys and skeletal muscles of aging male cohorts of two F1 hybrid strains of Mus musculus varied from 0.59 to 10.96 × 10-5 and did not increase as a function of donor age (up to 40 months). Resistant clones were shown to be severely deficient in the activity of hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8). These deficiencies presumably resulted from molecular alterations at this X-linked locus, including point mutations. No alterations of the X-chromosome were observed at the level of the light microscope. These results are inconsistent with predictions of the intrinsic mutagenesis and protein synthesis error catastrophe theories of aging. They do not rule out, however, somatic mutational theories that invoke comparatively large-scale chromosomal lesions, many of which would be likely to be lethal at the cellular level.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041210207
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  • 8
    Electronic Resource
    Electronic Resource
    Mouse teratocarcinoma cells resistant to aphidicolin and arabinofuranosyl cytosine: Isolation and initial characterization (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 115 (1983), S. 9-14 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: With the long-range goals of elucidating the biochemical genetics and the phenotypic expression, both in vitro and in vivo, of mutator strains of mammalian cells, we have isolated and partially characterized a series of drug resistant mutants from a subline of a feeder-dependent parental mouse teratocarcinoma line (PSA-1) known to be capable of chimerizing host blastocyts via the injection of inner cell mass. Two series of stable mutants were isolated - one (Aphr) selected on the basis of resistance to aphidicolin (Aph), a specific inhibitor of DNA polymerase-α, and the other (AraCr) selected by resistance to arabinofuranosyl cytosine, an analogue of cytosine. Irrespective of the method of selection, most of the 32 mutants isolated were resistant to both agents, although to different degrees, and with variations in growth characteristics, deoxynucleoside sensitivities, and sensitivities to mutagens (5-bromodeoxyuridine, N-methyl-N′-nitro-N-nitrosoguanidine and ultraviolet light). A protocol of multi-step selection provided stable mutants highly resistant to aphidicolin and only mildly resistant to AraC, even in the absence of prior mutagenesis, and is thus recommended as an approach to the isolation of candidate mutator strains of multipotent teratocarcinomas.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041150103
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  • 9
    Electronic Resource
    Electronic Resource
    Evidence that a critical threshold of DNA polymerase-alpha activity may be required for the initiation of DNA synthesis in mammalian cell heterokaryons (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 113 (1982), S. 141-151 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The specific activity of DNA polymerase (90% alpha) was determined in nine “neoplastoid” cell lines (Martin and Sprague, 1973) and in three different strains of HDF (human diploid fibroblast-like cells), all examined in logarithmic phases of growth. This was compared to the ability of each cell type to “rescue” (reinitiate DNA synthesis in) senescent HDF cells subsequent to polyethylene glycolmediated cell fusions. A sharp “threshold” value of DNA polymerase activity was observed below which reinitiation of DNA synthesis in heterokaryons with senescent HDF does not occur. This threshold was especially obvious when the specific activity of DNA polymerase (p moles dTTP incorporated per mg protein or per cell) was divided by the percent of S-phase cells present in each culture as determined by flow microfluorometry. Our results indicate that the specific activity of DNA polymerase-alpha (or some other factor tightly coregulated with it) in “recessive” cell types (those unable to rescue senescent cells) is only about two times this theoretical “threshold” value, and that fusion of recessive cell types to senescent HDF cells reduces the specific activity in the heterokaryon to below this minimum, thus preventing the cells from entering S phase.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041130123
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Delayed and reduced cell replication and diminishing levels of DNA polymerase-α in regenerating liver of aging mice (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 118 (1984), S. 225-232 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Kinetics of cell replication was compared in regenerating livers of Mus musculus at ages ranging between 6 and 32 months. Incorporation of [3H]-thymidine into DNA and autoradiographic analysis showed that the maximal extent of DNA replication following partial hepatectomy became delayed with age. Furthermore, the total fraction of parenchymal and nonparenchymal cells in S phase at different intervals during regeneration diminished as mice aged. The specific activity of DNA polymerase-α, the putative replicative enzyme, declined progressively during aging. The specific activity of DNA polymerase-β, the purported repair enzyme, declined to an appreciably lesser extent during the lifespan of the mouse. No evidence was found for the appearance of a specific inhibitor of polymerase-α in senescent mouse liver. Also, the bulk of the activities of both hepatic DNA polymerase-α and -β remained localized in the cell nucleus throughout the lifetime of the animal and were mainly associated with chromatin.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041180302
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    Paper (German National Licenses)
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