We investigated whether the small litter size in the 129 inbred mouse strain results from a reduction in oocyte fertilizability. Sensitivity of the zona pellucida to α-chymotrypsin was examined for oocytes collected at 14 h (shortly after ovulation), 17 h, and 20 h after hCG injection. Passage of spermatozoa through the zona pellucida (using an in vitro fertilization (IVF) technique) and the de...

Background: The oocyte is a unique cell committed to reprogram fertilizing sperm and to support early stages of embryonic development until the species-specific stage of zygote genome activation that occurs around the second to third cell cycle in sheep embryos. In this sense, considering the huge list of oocyte transcripts, we selected some candidates genes based on their roles of regulating di...

The mammalian zona pellucida contains several glycoproteins whose oligosaccharide moieties are known to play a key role in the interaction with spermatozoa. Since zona pellucida defects may represent one of the most likely causes of failed fertilization in human in-vitro reproduction, we have studied the carbohydrate composition and distribution over the human zona pellucida by means of lectins...

Fine structures of the zona radiata in zebrafish, Danio rerio, is examined and compared. The zona radiata (called as zona pellucid in mammals), is a porous structure located between oolemma and follicle cell epithelium in fish, has various functions. The zona radiata is an inner connection surface that regulates essential transition from follicle cells to oocytes and from oocytes to follicular ...

The zebrafish (Danio rerio) is an extremely dynamic organ in which follicles undergo asynchronous development. The oocytes of zebrafish ovary are observed in various phases. The oocyte development of zebrafish was divided into four stages (primary growth, cortical alveolus-previtellogenic, vitellogenic and mature oocyte). Zebrafish follicles contain only a single layer of granulosa cells that a...

Background: Artificial oocyte activation (AOA) has important implications in assisted reproductive technique (ART) with particular importance in somatic cell nuclear transfer (SCNT). Parthenogenesis activation using zona- free oocytes offers an alternative model that could be applied to develop protocols for the activation of reconstructed embryos for cloning. Materials and Methods: To establis...

In mammals, immature oocytes are surrounded by a layer of flattened cells. At this early stage of development, these "follicle cells" and the plasma membrane of the oocyte are in close proximity. As the oocyte matures, the follicle cells multiply and become cuboidal or radially elongated, and a jelly-like substance containing polysaccharides (1) appears between the oocyte cortex and the follicl...

BACKGROUND The aim of this work was to examine the effect of 1,2-propanediol (PrOH) and type of cryopreservation procedure (slow freezing and vitrification) on oocyte physiology. METHODS Intracellular calcium of mouse metaphase II (MII) oocytes was quantified by fluorescence microscopy. The effect of PrOH on cell physiology was further assessed through analysis of zona pellucida hardening and...

Electroejaculate traits and circulating follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone concentrations were analyzed in adult leopard cats (Felis bengalensis), a rare felid species indigenous to east Asia. The ability of leopard cat sperm to bind and penetrate zona-free hamster ova and zona-intact domestic cat oocytes in vitro was examined as a means of testing sp...

The aim of this study was to assess the predictive value of the hypoosmotic sperm swelling test. Good correlations were observed between the percentage of spermatozoa undergoing swelling and the percentage motility both in normal (r = 0.68; p < 0.001) and infertile patients (r = 0.65; p < 0.001). In contrast, sperm swelling did not significandy correlate either with sperm oocyte fusion (assesse...