Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 0886-1544
    Keywords: intermediate filaments ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sea urchin spermatozoa, eggs, and embryos were labeled with the universal antibody against the intermediate filament proteins (anti-IFA) described by Pruss et al. [Cell 27:419-428, 1981] and with anti-beta-tubulin. Localization of these antibodies was by indirect immunofluorescence microscopy. Cytoskeleton of unfertilized eggs, prepared according to a procedure adapted from Kane [Exp. Cell Res. 162:495-506, 1986] or as described by Dufresne et al. [Biochem. Cell Biol. 66:780-791, 1988], and reacted with the anti-IFA demonstrate a uniformly stained background except for the nuclear areas, which appear as dark rings. During the first cell cycle, the anti-IFA staining pattern coincides with that of spindle-associated tubulin but not with the cortical pattern of microtubules. Swimming embryos reacted with the anti-IFA show a labeling located on the cilia and within the cytoplasm of each individual cell of the larva. In spermatozoa, the labeling occurs all along the flagellae. Immunoblots of proteins from eggs and embryos reveal one major protein of 117 kDa and sometimes a component of 66 kDa, both of which cosediment with tubulin during the isolation procedure of microtubules described by Vallee and Bloom [Proc. Natl. Acad. Sci. USA 80:6259-6263, 1983]. These data show that proteins homologous to the intermediate filament proteins reported in vertebrate cells are present in both gametes of sea urchins. The specific localization ofthese proteins in the spindle, the flagella, and the cilia suggest that they may play a significant role in the organization and function of the microtubular lattice of the spermatozoa and of the embryo.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0886-1544
    Keywords: intermediate filaments ; phosphorylation ; sea urchin embryos ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of 6-dimethylaminopurine (6-DMAP) on the length of the cell cycle and on the state of phosphorylation of a putative intermediate filament protein, p117, have been studied in sea urchin embryos. Embryos were transferred into sea water containing 600 μM 6-DMAP at 0.5, 2 or 5 min after insemination, and incubated for 30 or 90 min. The effects of 6-DMAP on cell cycle length were studied by determining the time required for completion of mitosis upon return of the embryos in normal sea water. In all instances, except for the embryos transferred 0.5 min after insemination (AI) and incubated for 30 min, the duration of the M phase was shortened compared to controls, being faster in the embryos incubated for 90 minutes compared to the 30 min incubation period. However, embryos transferred 0.5 min AI have a longer M-phase than those transferred 2 minutes or later after fertilization, suggesting that between 0.5 and 2 min after fertilization, critical phosphorylating events occur which affect the commitment of the cells to enter M-phase.To study the pattern of p117 phosphorylation during the cell cycle, the eggs were transferred 2 minutes after fertilization in presence of 600 μM 6-DMAP and with 200 μCi/ml of 32P-orthophosphate. Analyses of 32P-labelled proteins after exposure of SDS-PAGE gels and their corresponding blots suggested that phosphorylation of p117 greatly increases at the time of pronuclear fusion, and then declines slightly at prophase-metaphase. This decrease is markedly enhanced when the cells are treated with 6-DMAP during metaphase in order to induce a premature breakdown of the mitotic apparatus. A causal link is suggested between the level of phosphorylation of p117 and its state of assembly. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1059-910X
    Keywords: Heparan sulfate proteoglycans ; Nephrogenesis ; Glomerular basement membranes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In vivo labeling of infant rat and mouse glomerular basement membranes (GBMs) with polyclonal anti-laminin IgGs results in binding across the full widths of GBMs at all stages of development. These stages include the pre-fusion, double basement membranes found beneath endothelial cells and podocytes in early glomeruli, and the subepithelial matrix outpockets where newly synthesized GBM is spliced into fused basement membrane during glomerular maturation. Identical binding results are obtained either with peroxidase or post-embedding immunogold techniques. Although injected cationized ferritin also binds abundantly to all developing GBMs, it quickly disappears and, 24 hours after injection, is generally absent from GBMs but remains within mesangial matrices. Injection of newborn mice with monoclonal anti-laminin IgGs results in dense labeling of pre-fusion GBMs but post-fusion GBMs and subepithelial outpockets are weak-negative. Although masking can not be excluded, these results indicate that laminin epitopes are removed during GBM fusion and splicing, either by isoform substitution or proteolytic processing. The loss of bound cationized ferritin is believed to occur mainly through rapid turnover of GBM proteoglycans. © 1994 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We have previously localized an antigen of oviductal origin to the zona pellucida of superovulated hamster oocytes (Kan et al.: Journal of Histochemistry and Cytochemistry 36:1441 - 1447, 1988) and described the intracellular distribution of this antigen in the oviductal epithelium (Kan et al.: Biology of Reproduction 40:585 - 598, 1989). These results led to our hypothesis that the oviduct is a bona fide site of origin of certain components of the zona pellucida. In this report, using the high resolution lectin-gold approach with Helix pomatia lectin (HPL)-colloidal gold complex, we present cytochemical evidence to show that glycoconjugates containing terminal N-acetyl-D-galactosamine residues are absent from the zona pellucida of ovarian oocytes but are synthesized and secreted by the nonciliated secretory cells of the oviduct and later become associated with well-defined structural elements of the zona matrix of oocytes during passage through the oviduct. The nature of the HPL-binding glycoconjugates was determined by biochemical analyses. Electrophoretic and immunological experiments demonstrated that the glycoconjugates correspond to the high molecular weight polydispersed glycoprotein that we have previously described. We have designated this glycoprotein “hamster oviductin 1” (IIm OV-1). Our results further substantiate the belief that the oviduct is a source of origin of zona pellucida constituents.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...