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Egg Interaction (egg + interaction)
Selected AbstractsCharacterization of Xenopus egg membrane microdomains containing uroplakin Ib/III complex: roles of their molecular interactions for subcellular localization and signal transductionGENES TO CELLS, Issue 2 2007A.K.M. Mahbub Hasan A single-transmembrane protein uroplakin III (UPIII) and its tetraspanin binding-partner uroplakin Ib (UPIb) are members of the UP proteins that were originally identified in mammalian urothelium. In Xenopus laevis eggs, these proteins: xUPIII and xUPIb, are components of the cholesterol-enriched membrane microdomains or "rafts" and involved in the sperm,egg membrane interaction and subsequent egg activation signaling via Src tyrosine kinase at fertilization. Here, we investigate whether the xUPIII-xUPIb complex is in close proximity to CD9, a tetraspanin that has been implicated in the sperm,egg fusion in the mouse and GM1, a ganglioside typically enriched in egg rafts. Preparation of the egg membrane microdomains using different non-ionic detergents (Brij 98 and Triton X-100), chemical cross-linking, co-immunoprecipitation, in vitro kinase assay and in vitro fertilization experiments demonstrated that GM1, but not CD9, is in association with the xUPIII-xUPIb complex and contributes to the sperm-dependent egg activation. Transfection experiments using HEK293 cells demonstrated that xUPIII and xUPIb localized efficiently to the cholesterol-dependent membrane microdomains when they were co-expressed, whereas co-expression of xUPIII and CD9, instead of xUPIb, did not show this effect. Furthermore, xUPIII and xUPIb were shown to suppress kinase activity of the wild type, but not a constitutively active form of, Xenopus Src protein co-expressed in HEK293 cells. These results provide novel insight into the molecular architecture of the egg membrane microdomains containing xUPIII, xUPIb and Src, which may contribute to the understanding of sperm,egg interaction and signaling during Xenopus fertilization. [source] The zona pellucida of the koala (Phascolarctos cinereus): its morphogenesis and thicknessJOURNAL OF ANATOMY, Issue 3 2006Jamie A. Chapman Abstract In this study the ultrastructural organization of the koala oocyte and the thickness of the surrounding extracellular coat, the zona pellucida, has been determined to ascertain whether there is coevolution of the morphology of the female gamete with that of the highly divergent male gamete that is found in this marsupial species. Ovaries from several adult koalas were obtained and prepared for transmission electron microscopy. Oocytes in large tertiary follicles were somewhat smaller than those of most other marsupials, although their ultrastructural organization appeared similar and included many yolk vesicles. The zona pellucida surrounding the oocytes in tertiary follicles was approximately 8 µm thick and thus is of similar thickness to that of some eutherian mammals but at least twice as thick as that of most marsupial species so far studied. The results indicate that the koala oocyte is unusually small for a marsupial species whereas the zona pellucida is, by contrast, much thicker. How this relates to sperm,egg interaction at the time of fertilization has yet to be determined. [source] Effects of tributyltin(IV) chloride on fertilization of Styela plicata (Ascidiacea: Tunicata): II.APPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2003Scanning, transmission electron microscopy studies Abstract The morphological aspects of Styela plicata fertilization after treatment with tributyltin(IV) chloride are described by means of scanning and transmission electron microscopy investigations. Alterations have been shown both on female and male gametes; spermatozoa, all the egg envelopes and the mitochondria of the egg cortical cytoplasm are modified in relation to incubation time. As a consequence, the damage to gametes blocks sperm,egg interaction and fertilization does not occur. Copyright © 2003 John Wiley & Sons, Ltd. [source] Egg jelly influences sperm motility in the externally fertilizing frog, Crinia georgianaJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2009L. W. SIMMONS Abstract Recent in vitro fertilization studies have revealed female and male × female interaction effects on the probability of fertilization. These findings suggest a mechanism of cryptic female choice via sperm,egg interactions. The egg jelly of anuran amphibians contains proteins that facilitate the chemoattraction and binding of sperm for fertilization. Here we show that egg jelly also influences the onset of motility and swimming velocity of motile sperm in the frog Crinia georgiana. Moreover, we found significant among female variation in the effects of egg jelly on sperm motility. We discuss this finding with respect to male and female effects on nonrandom fertilization observed in this species. [source] Molecular biology of sperm,egg interactionsANDROLOGIA, Issue 6 2005J. Dean No abstract is available for this article. [source] | ||||||||||