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  • 1
    Electronic Resource
    Electronic Resource
    A scanning electron microscope study of the mesothoracic and metathoracic scolopophorous organs of Lethocerus (Belostomatidae-heteroptera) (1980)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 163 (1980), S. 27-35 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The presence of scolopophorous organs in aquatic Heteroptera has been reported in a number of species. This study presents a morphological investigation of these sensory structures of Lethocerus (Belostomatidae) as observed with the scanning electron microscope (SEM). Paired mesothoracic and metathoracic organs are present. Externally, each sensory structure consists of a raised sensory membrane. The distal-most portion consists of thickenings of this sensory membrane (sclerite). The receptor neurons of the mesothoracic organ are of two types - one discolopidial sensillum and 12 monoscolopidial sensilla. The former is attached to the internal wall and distal thickening of the sensory membrane, while the latter are dispersed throughout the interior and attached to the internal wall of the sensory membrane. The structure of the organs suggest that an effective stimulus could be a compression of the membrane. A discussion of possible functions (pressure reception and hearing) is included.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051630105
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  • 2
    Electronic Resource
    Electronic Resource
    Localization of the centriole and keratin intermediate filaments in PtK1 cells by double immunofluorescence (1984)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 241-247 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; centrosome ; tonofilaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present observations on the relative location of the centriole and keratin filament cap in motile PtK1 cells. Subconfluent cells were double labeled with anticentriole and antikeratin sera. These preparations revealed that the centriole is separate from, but neighboring, the keratin filament cap. Serial ultrathin sections confirm this observation. These observations are consistent with the idea that the microtubule organizing center and intermediate filament distribution center are not identical or concentric in PtK1 cells.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970040403
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  • 3
    Electronic Resource
    Electronic Resource
    Dynamics of keratin filaments and the intermediate filament distribution center during shape change in PtK1 cells (1984)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 169-181 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; motility ; cell spreading ; epithelial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Reorganization of intermediate filaments during cell spreading is examined by immunofluorescence, electron microscopy, and time-lapse video microscopy. A juxtanuclear cap, believed to correspond to the intermediate filament distribution center, was observed to be spatially related to the organization of the intermediate filament network as cells spread. A keratin cap was observed, which appeared spontaneously in motile PtK1 cells. Cap formation may be a consequence of retraction of intermediate filaments from the cytoplasm as cells move. The position of this juxtanuclear cap is related to the direction of movement, located on the side of the nucleus near the advancing edge of the cell. As the cell spreads, the cap disappears as the keratin filament network returns to the cytoplasm. Evidence presented here is consistent with the hypothesis that the distribution center mediates keratin filament organization during cell shape change.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970040303
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  • 4
    Electronic Resource
    Electronic Resource
    Primary photochemistry in the facultative green photosynthetic bacterium Chloroflexus aurantiacus (1983)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 22 (1983), S. 251-261 
    Details
    ISSN: 0730-2312
    Keywords: Chloroflexus aurantiacus ; primary photochemistry ; reaction centers ; bacterial reaction centers ; bacteriochlorophyll ; bacteriopheophytin ; menaquinone ; ubiquinone ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The mechanism of primary photochemistry has been investigated in purified cytoplasmic membranes and isolated reaction centers of Chloroflexus aurantiacus. Redox titrations on the cytoplasmic membranes indicate that the midpoint redox potential of P870, the primary electron donor bacteriochlorophyll, is +362 mV. An early electron acceptor, presumably menaquinone has Em 8.1 = -50 mV, and a tightly bound photooxidizable cytochrome c554 has Em 8.1 = +245 mV. The isolated reaction center has a bacteriochlorophyll to bacteriopheophytin ratio of 0.94:1. A two-quinone acceptor system is present, and is inhibited by o-phenanthroline. Picosecond transient absorption and kinetic measurements indicate the bacteriopheophytin and bacteriochlorophyll form an earlier electron acceptor complex.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240220407
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  • 5
    Electronic Resource
    Electronic Resource
    Concepts of epithelial-mesenchymal interactions during development: Tooth and lung organogenesis (1984)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 26 (1984), S. 117-125 
    Details
    ISSN: 0730-2312
    Keywords: gene expression ; amelogenins ; cDNA ; type II cells ; pulmonary surfactant ; ameloblasts ; epithelial differentiation ; regional mesenchymal specificity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: One of the major problems in developmental biology concerns how differential gene activity is regionally controlled. One approach to this problem is the use of mesenchyme specification of epithelial-specific gene expression, such as, during tooth morphogenesis or lung morphogenesis. In the example of tooth morphogenesis, dental papilla ectomcsenchyme induces de novo gene expression as assayed by detection of amelogenin transcripts, or immunodetection of amelogenin poly-peptidcs within ameloblast cells. This process does not require serum supplementation or exogenous factors during epithelial-mesenchymal interactions in vitro. In contrast, lung morphogenesis requires hormones to mediate mesenchyme-derived influences upon type II epithelial cell differentiation and the production of pulmonary surfactant (eg, neutral and phospholipids, surfactant proteins). Glucocorticoids are required to stimulate the release of fetal pneumonocyte factor (FPF) from fibroblasts which, in turn, enhance the production of pulmonary surfactant. Thy-roxin appears to regulate the relative responsiveness of progenitor type II cells to steroid-stimulated release of FPF. This review will highlight key concepts associated with these developing organ systems and emphasize the problem of regional controls which regulate epithelial cell-specific gene activity.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240260207
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  • 6
    Electronic Resource
    Electronic Resource
    A basement membrane-associated glycoprotein from skeletal muscle (1982)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 19 (1982), S. 363-381 
    Details
    ISSN: 0730-2312
    Keywords: basement membrane ; extracellular matrix ; muscle ; structural glycoprotein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have isolated a major glycoprotein that appears to be associated with rat skeletal muscle basement membrane. We determined that the glycoprotein was part of the muscle cell surface complex when we found it to be enriched in preparations of muscle ghosts. We isolate the glycoprotein from homogenized muscle preextracted with 4 M and 8 M urea. It elutes as a major component in the presence of 8 M urea/50 mM 2-mercaptoethanol. Its apparent molecular weight on sodium dodecyl sulfate gels is 130,000. Amino acid analysis indicates that it is not a collagen but that it does contain small amounts of hydroxyproline and hydroxylysine. There may be collagenous domains in the glycoprotein molecule, for it is cleaved into three fragments by purified bacterial collagenase. Immunoperoxidase staining confirms that the 130,000-dalton protein is localized at the surface of adult skeletal muscle cells. It is probably a general basement membrane-associated glycoprotein because we found material immunologically cross-reactive with the muscle glycoprotein in basement membrane regions of kidney, liver, brain, and small intestine. We have shown the glycoprotein to be distinct from fibronectin, laminin, and types I, III, IV, and V collagens in enzyme-linked immunosorbent assays.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240190406
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  • 7
    Electronic Resource
    Electronic Resource
    The effects of cold-stress, hibernation, and prolonged inactivity on bone dynamics in the golden hamster, Mesocricetus auratus (1981)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 167 (1981), S. 43-51 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of cold-stress and hibernation on bone dynamics in the femurs of hamsters were investigated using histometric analyses. Control animals were maintained at 27° C for 90 days; experimental animals were kept at 5° C and hibernated for 7, 15, 21, 50, or 90 days. Histometric analyses of cross sections indicated that bone diameter and cortical thickness at the femoral midshaft increased after 83 days of extreme cold and 7 days of hibernation but decreased significantly after 69 days of cold stress and 21 days of hibernation. Osteoporosis was evident although the number of osteons per unit area of bone increased during hibernation. An initial decrease in the number of non-Haversian longitudinal vessels per unit area of bone was seen in experimental animals which was apparently related to a corresponding reduction in cortical thickness. Lacunar area increased in these animals, suggesting that osteocytic osteolysis may be a significant mechanism for calcium regulation during hibernation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051670105
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  • 8
    Electronic Resource
    Electronic Resource
    Regulation of mitotic activity and the cell cycle in primary chick muscle cells by neurotransferrin (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 119 (1984), S. 234-240 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We previously demonstrated that neurotransferrin (NTF), a transferrin extracted from adult chicken peripheral nerves, promotes growth of primary chick muscle cells in the absence of embryo extract. NTF was shown to stimulate DNA synthesis and cell proliferation. In the present study, we demonstrate that NTF is a mitogen using two independent methods; counts of orcein-stained mitotic figures and analysis of cell cycle kinetics with a fluorescence-activated cell sorter. In low-density cultures mitotic activity increases with increasing doses of NTF followed by a plateau at concentrations greater than 6 μg/ml. Residual, embryonic mitotic activity progressively declines with time after plating muscle cells in the absence of NTF. Absence of NTF for 2 days causes cells to lose irreversibly their myogenic potential. In the presence of NTF, mitotic activity increases for 2 days followed by a decline concurrent with myoblast fusion and formation of myotubes. Cell cycle analysis showed that NTF addition causes cell populations to shift from Gt to S and G2 + M within 18.5 hr. Muscle cells, plated at high densities in the absence of NTF, show mitotic activities similar to those plated at low densities in the presence of NTF. Addition of NTF to high-density cultures is ineffective in stimulating mitosis. These studies show that at typical cell plating densities, NTF is a required mitogen for primary chick muscle cell cultures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041190214
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  • 9
    Electronic Resource
    Electronic Resource
    Plasminogen activator: The major secreted neutral protease of cultured skeletal muscle cells (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 110 (1982), S. 190-195 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Clonal mouse skeletal muscle cells which differentiate in culture and from synpases with neuronal cells were found to secrete high levels of protease activity as measured with an 125I-fibrin assay. The secreted proteolytic activity was more than 90% dependent upon the presence of plasminogen in the medium, and had a pH optimum at 7 to 8. This activity was not inhibited by n-ethylmaleimide, pepstatin, EDTA, or EGTA. At millimolar concentrations, greater than 90% inhibition was obtained with either soybean typsin inhibitor, epsilon aminocaproic acid, Trasylol, or leupeptin. Almost complete inhibition occured with 1 mM diisopropylfluorophosphate suggesting the presence of a serine residue at the catalytic site. In contrast to the high levels of secreted activity, a lower steady-state level of cell-associated protease activity was detected in cell lysates. The high level of plasminogen activator secreted into the medium of cultured muscle cells suggests a role for such extracellular protease activity in myogenesis during development and remodeling following muscle injury. Such information may be useful in understanding the initial degeneration of neuromusclar contacts in experimental and pathologic denervation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041100213
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  • 10
    Electronic Resource
    Electronic Resource
    The effects of taurine and hypotaurine on in vitro fertilization in the golden hamster (1981)
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 57-63 
    Details
    ISSN: 0148-7280
    Keywords: taurine ; hypotaurine ; spermatozoa ; in vitro fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Taurine and hypotaurine were examined for their efficacy in replacing sperm motility factor (SMF), prepared from bovine adrenal cortex, for in vitro fertilization in the golden hamster. Combinations of these amino acids at concentrations of 0.001, 0.01, 0.1, and 1 mM together with 16 μM isoproterenol (a catecholamine β-agonist) were added to the sperm incubations. After three hours of sperm preincubation, oviductal eggs were added to the sperm suspensions and examined for penetration and stage of fertilization after three or five hours of culture. At 0.001 mM, neither taurine or hypotaurine was capable of maintaining motility of hamster sperm for four to 4½ hours or of inducing fertilization. With all other concentrations, both amino acids were found to maintain motility of sperm as well as SMF. Hypotaurine stimulated motility to a greater extent than taurine and both required isoproterenol for the greatest motility. A low proportion of cumulus-free ova were fertilized when sperm were preincubated with either amino acid alone over the range of 0.01 to 1 mM; however, over 80% fertilization was consistently obtained when isoproterenol was also present during sperm incubation. Proportions of ova fertilized with taurine or hypotaurine present during sperm preincubation were comparable to those achieved with SMF. The possibility that taurine or hypotaurine is the sperm motility factor is discussed.After three hours of sperm/egg incubation, a lag in the early events of fertilization was observed in experimental groups treated with one of the amino acids (0.01 mM) alone compared with groups treated with isoproterenol present. However, if sperm/egg incubation was extended from three to five hours, no increase in number of eggs penetrated was found. Therefore, the delay observed at three hours was considered a function of fewer numbers of capacitated sperm present in the absence of isoproterenol rather than of the need for an extended capacitation time.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120040109
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