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  • 1
    Electronic Resource
    Electronic Resource
    Injection of isolated centriolar complex to induce mitosis in starfish eggs (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 26 (1990), S. 356-360 
    Details
    ISSN: 1040-452X
    Keywords: Sperm centriolar complex ; Initiation of mitosis ; Oocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: When centriolar complex isolated from starfish spermatozoa was injected into starfish immature oocytes (fully grown, germinal vesicle stage) followed by treating the latter with 1-methyladenine, mitotic events such as condensation and division of chromosomes of the female pronucleus and cytokinesis following completion of meiosis were observed. No cortical reaction detected in the oocytes. Essentially the same was noted for mature oocytes (pronuclear stage) into which the centriolar complex had been injected. The oocytes that had received sperm tail fraction or buffer alone did not initiate cleavage. It would thus appear that sperm centriolar complex is significantly essential to the initiation of cleavage.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080260410
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  • 2
    Electronic Resource
    Electronic Resource
    Cyclic appearance of cytoplasmic NOR-silver-stained particles in sea urchin embryos (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 29 (1991), S. 245-252 
    Details
    ISSN: 1040-452X
    Keywords: Sea urchin ; Cytoplasmic NOR-silverstained particles ; Cell cycle ; Development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: When sea urchin embryos were subjected to nucleolar organizer region (NOR)-silver staining, densely stained particles were observed in the cytoplasm. The appearance of these cytoplasmic particles (CPs) was cell-cycle dependent. During early development, the CPs were detected at interphase, but not during mitosis; they disappeared at metaphase and reappeared at telophase. The CPs appeared periodically even when embryos were treated with cytochalasin B or aphidicolin, which inhibits the progression of cytokinesis and nuclear division, respectively. By contrast, CPs were not detected in the colchicine-treated embryos in which both cytokinesis and nuclear divisions were prevented. The CPs were observed only in the embryos whose stage was early blastula (about 6th to 7th cleavage) or earlier; no CPs were detected even at interphase in the embryos at late blastula (about 8th to 9th cleavage) or later. Electron microscopic evaluation showed CPs to be granular structures, similar to heavy bodies. Also, sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) showed that 95-kDa and 38-kDa proteins were the NOR-silver-staining proteins in sea urchin embroys. These proteins existed during the course of the cell cycles. These results suggest that (1) the cyclic appearance of the CPs or heavy bodies is closely related to the cell cycle as well as the programming of the embryogenesis, but independent of the cycle of cytokinesis and nuclear division; (2) 95-kDa and 38-kDa proteins are the major NOR-silver-staining proteins in sea urchin embryos.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080290306
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  • 3
    Electronic Resource
    Electronic Resource
    The fate of DNA originally existing in the zygote nucleus during achromosomal cleavage of fertilized echinoderm eggs in the presence of aphidicolin: Microscopic studies with anti-DNA antibody (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 124 (1985), S. 9-12 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In fertilized echinoderm eggs, the male and female pronuclei fuse to form the diploid nucleus even in the presence of aphidicolin, a specific inhibitor of eukaryotic DNA polymerase-α. The subsequent first cleavage is independent of chromosomes but dependent on spindle and amphiaster. The fate of DNA originally existing in the fused nucleus during achromosomal cleavage of fertilized sea urchin and starfish eggs induced by aphidicolin was determined using antidenatured DNA antibody. The nucleus is not formed in the divided daughter cells at the two-cell stage but the nuclear-envelope-free chromatin mass which is unassociated with mitotic apparatus remains in the center region of embryos, especially near the first cleavage furrow. These results indicate that the condensed and nonreplicated chromatin can not be associated with spindle and asters in the presence of aphidicolin.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041240103
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  • 4
    Electronic Resource
    Electronic Resource
    Induction of achromosomal cleavage by hydroxyurea in starfish embryo and the reversal by a combination of deoxyadenosine and deoxycytidine: Possible involvement of salvage pathway for deoxynucleoside triphosphate biosynthesis in the presence of hydroxyurea (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 136 (1988), S. 326-332 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Effects of hydroxyurea, an inhibitor of ribonucleotide reductase, on cleavage of starfish embryos were studied. In the presence of 1 mM hydroxyurea, fertilized eggs of the starfish, Asterina pectinifera, cleaved up to the 256-cell stage and decomposed before blastulation. Before the 16-cell stage, each blastomere contained a normal nucleus or chromosomes with mitotic apparatus. The cleveage after the 16-cell stage was slow compared to the control embryos, and not all blastomeres contained a nucleus or normal chromosomes. During the fifth cell division (between 16-cell- and 32-cell-stage embryos), chromatin mass unassociated with the mitotic apparatus remained near the cleavage furrow. When hydroxyurea was removed before the 16-cell stage, the embryos developed to normal bipinnalia larvae via normal blastulae. However, the embryos were disintegrated before blastulation when hydroxyurea was removed after the 32-cell stage. DNA synthesis was normally observed before the 16-cell stage but not after the 16-cell stage, but dNTP contents in the embryos remained low throughout development in the presence of hydroxyurea. The achromosomal cleavage observed in the presence of hydroxyurea was reversed by the combination of extracellular dAR and dCR. Therefore, it is assumed that the synthesis of dNTPs required for DNA synthesis in the presence of hydroxyurea occurs via the salvage pathway using deoxynucleosides (dNR) (dNR to dNTP via dNMP and dNDP).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041360216
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  • 5
    Electronic Resource
    Electronic Resource
    Initiation of cleavage in starfish eggs by the injection of triton-treated spermatozoa (1986)
    New York, NY : Wiley-Blackwell
    Gamete Research 13 (1986), S. 135-141 
    Details
    ISSN: 0148-7280
    Keywords: starfish ; oocytes ; sperm injection ; cortical reaction ; cleavage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Triton X-100-treated spermatozoa were injected into immature (fully grown, germinal vesicle stage) or mature (pronuclear stage) oocytes of the starfish, Asterina pectinifera, to study relation between initiation of cleavage and cortical reaction. Immature oocytes into which Triton X-100-treated spermatozoa were injected were treated with 1-methyladenine. Such immature oocytes initiated cleavage after completion of meiosis without formation of the fertilization membrane. The same results were obtained when Triton X-100-treated spermatozoa were injected into mature oocytes. Control oocytes into which only calcium-free sea water was injected did not cleave. These results indicate that the initiation of cleavage is independent of the cortical reaction but dependent on the existence of spermatozoa (spermatozoon) in the egg cytoplasm.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120130206
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  • 6
    Electronic Resource
    Electronic Resource
    Intracellular localization of argyrophilic proteins in the maturing oocyte, fertilized egg, and spermatozoa of the starfish, Asterina pectinifera (1987)
    New York, NY : Wiley-Blackwell
    Gamete Research 16 (1987), S. 291-301 
    Details
    ISSN: 0148-7280
    Keywords: NOR-silver staining ; GVBD ; yolk-like granules ; sperm nucleus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Changes in intracellular localization of argyrophilic proteins visualized as silver-stained particles by nuclear organizer region (NOR)-silver staining were investigated in starfish oocyte maturation. The silver-stained particles were localized in the germinal vesicle and nucleolus of immature oocytes and dispersed into the cytoplasm at the time of germinal vesicle breakdown (GVBD). In the mature egg cytoplasm, silver-stained particles were distributed on yolk-like granules with diameters of 0.3-1.0 μm. In spermatozoa, silver-stained particles were detected heavily in the acrosome and centrosomes but few were detected in the nucleus, whereas they were present in the male pronucleus of fertilized eggs. The silver-stained particles were removed by pretreatment of eggs with protease but not with nuclease. These results indicate that argyrophilic proteins disperse to the egg cytoplasm during GVBD and might be incorporated to the male pronucleus from the egg cytoplasm in fertilization. The morphological changes from chromosomes through chromosome vesicles to female pronucleus were also observed with light microscopy after NOR-silver staining.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120160403
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  • 7
    Electronic Resource
    Electronic Resource
    Recessive (mediator-) revertants from c-h-ras oncogene-transformed NIH 3T3 cells: Tumorigenicity in nude mice and transient anchorage and serum independence of the recovered tumor cells in culture (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 149 (1991), S. 214-221 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have reported earlier the isolation of two recessive, serum- and anchoragedependent revertants (R116 and R260) from a c-H-ras oncogene-transformed NIH 3T3 line. In both revertants, the oncogene was fully expressed and fusion of either revertant with (untransformed) NIH 3T3 cells, or of the two revertants with one another, resulted in transformed progeny. These, and other data, indicated that the transforming activity of the oncogene was impaired in the two revertants in consequence of defects in distinct genes needed to mediate this activity.We report here that neither revertant could be re-transformed by the K-ras or N-ras oncogene (though they could be re-transformed by several other oncogenes). The two revertants turned out to be tumorigenic in nude mice (though less so than the parental transformed cells). The tumor cells, as recovered, formed foci and had a transformed morphology and a greatly diminished serum and anchorage dependence. Growth of the cells in culture (for 20 passages) resulted in their regaining the characteristics (i.e., anchorage and serum dependence) of cultured R116 and R260 cells. Proliferation of the cells in nude mice was not accompanied by a change in the level of ras oncogene expression or in gene amplification, at least as manifested in the lack of appearance of double-minute chromosomes. The addition of the growth factors TGF alpha and beta to the medium of either revertant did not support anchorage-independent growth.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041490207
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