Mammalian fertilization requires sperm to penetrate the cumulus mass and egg zona pellucida prior to fusion with the egg. Although sperm penetration through these physical barriers is essential, the molecular mechanism has not yet been completely elucidated. In addition to sperm motility, hyaluronan-hydrolyzing and proteolytic enzymes of sperm have been suggested to participate in the penetrati...

To fuse with oocytes, spermatozoa of eutherian mammals must pass through extracellular coats, the cumulus cell layer, and the zona pellucida (ZP). It is generally believed that the acrosome reaction (AR) of spermatozoa, essential for zona penetration and fusion with oocytes, is triggered by sperm contact with the zona pellucida. Therefore, in most previous studies of sperm-oocyte interactions i...

Oocytes collected from superovulated Swiss albino mice were activated by heat-shock and/or fertilized in vitro. Electron microscopy showed that the cortical reaction in heat-treated eggs was incomplete. Digestion of the zona pellucida of untreated, heat-treated and fertilized eggs by pronase showed that zona pellucida hardening did occur but was weaker in heat-treated than in fertilized eggs. F...

A couple with unexplained infertility was referred for routine IVF and ICSI treatment. Ovulation was induced by the GnRH analogue protocol combined with HMG and HCG. Preparation of denuded oocytes revealed a major disorder of the zona pellucida and abnormal oocytes. During preparation of ova for ICSI, 15 retrieved oocytes were denuded, 14 of which underwent ICSI treatment. Four of the oocytes c...

Granulosa cells play an important part in the nutrition of the oocyte during oogenesis (Raven, 1961). Anderson & Beams (1960) suggested that, in the primary follicle, nutritive material synthesized by the granulosa cells reaches the oocyte by diffusion across the zona pellucida. In the rabbit, follicle formation and elaboration of the zona pellucida begin at the end of the second week after bir...

BACKGROUND Assisted hatching (AH) in fresh embryo transfer (ET) could be associated with increased implantation rates. However, very few prospective randomized studies have specifically addressed the issue of AH during frozen-thawed embryo transfers (FET) cycles, those that have reported controversial results. The aim of this study was to evaluate the benefit of an enzymatic zona pellucida trea...

We examined the effect of fetal calf serum (FCS) on meiotic division, subsequent fertilization, and first cleavage to the 2-cell stage of rat oocytes during in vitro maturation. FCS had no effect on the nuclear progression from dictiate to metaphase of the second maturation in vitro and, FCS had no effect on the first cleavage to the 2-cell stage of fertilized oocytes. However, FCS efficiently ...

The changes that occur in the carbohydrate composition of zona pellucida glycoproteins during oocyte maturation in the wild-boar were studied using periodic-acid Schiff (PAS), High Iron Diamine (HID) and Low Iron Diamine (LID). Lectin staining was performed with a panel of 11 HRP-lectin conjugates combined with neuraminidase digestion and chemical treatments. There were few internal glucidic re...

The mammalian zona pellucida has an important function in the fertilization process. The zona pellucida protein 3 (ZP3 or ZPC) is the ligand for primary sperm binding and induces the acrosome reaction. In various species, ZP3 primary structures are highly conserved as revealed by cDNA cloning. The objective of these studies was to localize ZP3 protein using antisera generated against defined sy...

Studies using genetic and biochemical probes have suggested that mouse sperm surface galactosyltransferases may participate during fertilization by binding N- acetylglucosamine (GlcNAc) residues in the egg zona pellucida. In light of these results, we examined sperm surface galactosyltransferase activity during in vitro capacitation to determine whether changes in enzymatic activity correlated ...