Ultrastructural investigations on sperm penetration and gamete fusion in the ascidians Boltenia villosa and Phallusia mammillata

1993 ◽  
Vol 116 (1) ◽  
pp. 117-127 ◽  
Author(s):  
M. Xie ◽  
T. G. Honegger
Keyword(s):  
Gamete Fusion ◽  
Boltenia Villosa ◽  
Sperm Penetration

Mammalian gamete fusion depends on the inhibition of ovastacin by fetuin-B

2014 ◽  
Vol 395 (10) ◽  
pp. 1195-1199 ◽  
Author(s):  
Walter Stöcker ◽  
Konstantin Karmilin ◽  
André Hildebrand ◽  
Hagen Westphal ◽  
Irene Yiallouros ◽  
...  
Keyword(s):  
Plasma Protein ◽  
Zona Pellucida ◽  
Cortical Granules ◽  
Gamete Fusion ◽  
Mammalian Oocyte ◽  
Zona Hardening ◽  
Sperm Penetration ◽  
Cortical Vesicles

Abstract The zona pellucida, a glycoprotein matrix surrounding the mammalian oocyte, hardens after intrusion of the first spermatozoon, thus protecting the embryo until implantation and preventing multiple fertilizations (polyspermy). Definitive zona hardening is mediated by the metalloprotease ovastacin, which is released from cortical granules of the oocyte upon sperm penetration. However, traces of ovastacin seep from unfertilized eggs to cause zona hardening even in the absence of sperm. These small amounts of protease are inactivated by the plasma protein fetuin-B, thus keeping eggs fertilizable. Once a sperm has penetrated the egg, ovastacin from cortical vesicles overrides fetuin-B and initiates zona hardening.

In vitro fertilization in inbred BALB/c mice I: isotonic osmolarity and increased calcium-enhanced sperm penetration through the zona pellucida and male pronuclear formation

Zygote ◽  
2008 ◽  
Vol 16 (3) ◽  
pp. 249-257 ◽  
Author(s):  
Seiji Kito ◽  
Yuki Ohta
Keyword(s):  
Calcium Concentration ◽  
Detrimental Effect ◽  
Choline Chloride ◽  
Positive Control ◽  
Basic Medium ◽  
Vitro Fertilization ◽  
Medium Osmolarity ◽  
Sperm Penetration ◽  
Pronuclear Formation

SummaryTo optimize IVF conditions for BALB/c mice, which are known to have poor in vitro fertilizability, the requirements for sperm–ova interaction were studied by use of modified simplex optimization medium (mKSOM) as a basic medium. Modified human tubal fluid (mHTF) was used for sperm preincubation and acted as a positive control. When the two media were compared, neither capacitation nor fertilization was supported in mKSOM. Increasing the calcium concentration in mKSOM to 5 mM or more during sperm: ova coincubation improved zona penetration but not male pronuclear (MPN) formation to the same level as those cells incubated in mHTF. When medium osmolarity was varied from 230–305 mOsmol by NaCl at 5 mM CaCl2, MPN formation improved at 280 mOsmol or higher osmolarity to the same level as that found when using mHTF. When NaCl equivalent to 25–75 mOsmol was substituted with trehalose, no significant reduction in fertilization was observed. Substitution of NaCl equivalent to 75 mOsmol with other osmotic reagents (sucrose, choline chloride and sorbitol) resulted in similar levels of fertilization as found with mHTF, except for sorbitol, which reduced fertilization significantly caused by its detrimental effect on sperm viability. At isotonic osmolarity (305 mOsmol), maximum fertilization was observed at 5 mM CaCl2; lower or higher concentrations of CaCl2 resulted in reduced fertilization. Calcium and osmolarity, therefore, are important for sperm : ova interaction in BALB/c mice and the increases in calcium to 5 mM and osmolarity to 305 mOsmol are optimal for BALB/c sperm to penetrate through the zona and to form MPN.

scholarly journals PACAP-mediated sperm–cumulus cell interaction promotes fertilization

Reproduction ◽  
2011 ◽  
Vol 141 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Ichiro Tanii ◽  
Tadashi Aradate ◽  
Kouhei Matsuda ◽  
Akira Komiya ◽  
Hideki Fuse
Keyword(s):  
Sperm Motility ◽  
Acrosome Reaction ◽  
Cumulus Cell ◽  
Cumulus Cells ◽  
Cell Interaction ◽  
Fertilization Rate ◽  
Type I ◽  
Dependent Manner ◽  
Sperm Penetration

The developing acrosome in spermatids contains pituitary adenylate cyclase-activating polypeptide (PACAP). However, the role of the acrosomal PACAP remains unclear because it has not been detected in mature spermatids and sperm. We reinvestigated whether the sperm acrosome contains PACAP. An antiserum produced against PACAP reacted to the anterior acrosome in epididymal sperm fixed under mild conditions, suggesting that PACAP acts on oocytes and/or cumulus cells at the site of fertilization. Immunolabeling and RT-PCR demonstrated the presence of PACAP type I receptor, a PACAP-specific receptor, in postovulatory cumulus cells. To investigate the role of PACAP in fertilization, we pretreated cumulus–oocyte complexes with the polypeptide. At a low concentration of sperm, the fertilization rate was significantly enhanced by PACAP in a dose-dependent manner. Sperm penetration through the oocyte investment, cumulus layer, and zona pellucida was also enhanced by PACAP. The enhancement was probably due to an enhancement in sperm motility and the zona-induced acrosome reaction, which were stimulated by a cumulus cell-releasing factor. Indeed, PACAP treatment increased the secretion of progesterone from the cumulus–oocyte complexes. These results strongly suggest that in response to PACAP, cumulus cells release a soluble factor that probably stimulates sperm motility and the acrosome reaction, thereby promoting fertilization.

The use of sperm penetration assay in evaluation of men with varicocele*

1987 ◽  
Vol 47 (4) ◽  
pp. 680-683 ◽  
Author(s):  
Stephen R. Plymate ◽  
Rae R. Nagao ◽  
Charles H. Muller ◽  
C. Alvin Paulsen
Keyword(s):  
Sperm Penetration ◽  
Sperm Penetration Assay

Characterization of the Sperm Penetration Bioassay

1982 ◽  
Vol 3 (6) ◽  
pp. 445-451 ◽  
Author(s):  
DON P. WOLF ◽  
JOSEPH E. SOKOLOSKI
Keyword(s):  
Sperm Penetration
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