摘要:

AbstractSex cell adhesion in isogamous chlamydomonads is caused by a complementarity between sex‐specific mating type substances, glycoproteins anchored in the flagella membrane of (+) and (\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop - \limits^. $\end{document}) gametes. The systems of mating type substances are species‐specific and condition, by their individuality, gametic incompatibility between species. The adhesion systems of several species share one common feature: the attainment of the agglutination capacity is sensitive to tunicamycin, but in one sex only. The effect is interpreted as due to the interference of tunicamycin with the synthesis of the mating type substances by blocking of their glycosylation in one but not in the other sex. It is postulated that the tunicamycin‐sensitive gametic adhesiveness depends, within the mating‐type‐specific glycoprotein, on an N‐glycosidically bound ligand of carbohydrate nature. A concept on the origin of sibling species by mutative modulations within the proper ligands of the glycoproteinaceous mating type substances i

ISSN:0148-7280    

DOI:10.1002/mrd.1120050102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractStarfish oocyte maturation is triggered by a natural hormone, 1‐methyladenine (1‐MeAde), produced in the follicle cells, or artificially by dithiothreitol (DTT). These substances act on the oocyte surface to produce a cytoplasmic maturation‐promoting factor (MPF), which induces germinal vesicle breakdown (GVBD) and subsequent processes of meiotic maturation. Further, MPF is amplified in immature oocytes that have received the injection of MPF. In this paper the effect of leupeptin and antipain, protease inhibitors of microbial origin, on starfish oocyte maturation was investigated. The protease inhibitors were found to inhibit 1‐MeAde‐induced maturation when they were applied externally or injected into oocytes. DTT‐induced maturation was also inhibited by injection of leupeptin. However, leupeptin did not inhibit the maturation‐inducing action of MPF or MPF amplification. These results show that the protease inhibitors suppress the production of MPF by 1‐MeAde or DTT, suggesting that some endogenous protease(s) acts in the pr

ISSN:0148-7280    

DOI:10.1002/mrd.1120050103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe membrane mobility agent A2C accelerates the onset of the acrosome reaction of guinea pig spermatozoa by promoting capacitation. Spermatozoa incubated in a suspension of A2C particles in Ca2+‐free medium for one hour undergo a synchronous, rapid acrosome reaction upon the addition of Ca2+. These acrosome‐reacted spermatozoa are capable of fertilization as assessed by their ability to penetrate (fuse with) zona‐free hamster eggs.The disulfide‐reducing agent, dithiothreitol (DTT) inhibits A2C‐mediated capacitation. It also blocks fertilization of zone‐free eggs by acrosome‐reacted spermatozoa by preventing attachment of the spermatozoa to the egg plasma membrane.The mode of A2C action on spermatozoa is compared to that of A2C‐induced fusion in somatic cells. The similarity of the molecular events in the sperm membrane during capacitation and the acrosome reaction to these in other fusion events is pointed out.Inhibition of capacitation by DTT points to the importance of membrane and/or submembrane proteins and thiol groups in this process. Oxidation of sperm membrane SH groups may play an important role in in vi

ISSN:0148-7280    

DOI:10.1002/mrd.1120050104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractAutoantigens that appear during spermatogenesis in the rabbit were identified using immunoadsorbent chromatography and SDS‐PAGE. To identify cell‐surface proteins, samples of freshly isolated, staged cells were labeled by the lactoperoxidase or Iodo‐Gen iodination procedure and run on SDS‐PAGE. Autoradiograms of the stained, dried gels were prepared. By correlating the band patterns in the SDS gels of immunocolumn and surface‐labeled samples with the band patterns in the autoradiograms, it was possible to show when the autoantigenic proteins appeared on the cell surface. To further support the identification of membrane autoantigens, surface‐labeled, staged cell samples were lysed in Triton X‐100 and immunoprecipitated with antitestis cell autoantisera.Three types of autoantigens have been identified: (1) late class antigens that are present only on late spermatids and epididymal spermatozoa, but are intracellular in early stages, (2) early class antigens which occur on the surface of pachytene spermatocytes and are present throughout subsequent stages of development, and (3) early class, transient antigens, which appear on spermatogenic cells but are not present on epididyma

ISSN:0148-7280    

DOI:10.1002/mrd.1120050105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractInterphylum crossing was examined between sea urchin eggs (Temnopleurus hardwicki) and oyster sperm (Crassostrea gigas). The eggs could receive the spermatozoa with or without cortical change. The fertilized eggs that elevated the fertilization envelope began their embryogenesis. Electron microscopy revealed that oyster spermatozoa underwent acrosome reaction on the sea urchin vitelline coat, and their acrosomal membrane fused with the egg plasma membrane after the appearance of an intricate membranous structure in the boundary between the acrosomal process and the egg cytoplasm. Oyster spermatozoa penetrated sometimes into sea urchin eggs without stimulating cortical granule discharge and consequently without fertilization envelope formation. The organelles derived from oyster spermatozoa seemed to be functionally inactive in the eggs whose cortex remained unchanged.

ISSN:0148-7280    

DOI:10.1002/mrd.1120050106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe effect of varying the sperm concentration between 2 × 105sperm/ml and 8 × 106sperm/ml on fertilization of cumulus‐free, zona‐intact F1 (CBA × C57BL) mouse ova by QS and F1 (CBA × C57BL) mouse spermatozoa was studied. The spermatozoa from both strains of mice exhibited optimal fertilization rates at 2 × 106 sperm/ml. However, at sperm concentrations greater than 4 × 106 sperm/ml and less than 1 × 106 sperm/ml, fertilization rates were significantly reduced. F1 spermatozoa were more susceptible to dilution than QS spermatozoa. A significant interaction between strain and sperm concentration indicated that the two strains produced different fertilization rates at different sperm densities.Extracts of epididymal fluid, medium from capacitated spermatozoa, or ampulla fluid did not improve the fertilization rate at 2 × 105 sperm/ml, but retaining the cumulus oophorus did. The decrease in fertilization rate at 8 × 106 sperm/ml can in part be attributed to a nondialysable inhibitor from the neat sperm preparation that appeared to be of epidi

ISSN:0148-7280    

DOI:10.1002/mrd.1120050107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120050108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120050109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120050101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY