Oocyte-specific genes play important roles in regulating ovarian development, principally through the proper and timely progression of oogenesis and folliculogenesis. Development of transgenic mouse models has been critical in revealing how oocyte-specific transcripts influence oocyte development and growth, integrity of the oocyte-granulosa cell complex, oocyte maturation, fertilization, and e...

I N the adult hen each oocyte is surrounded by a capsule of follicle cells and all the raw materials that enter the oocyte must pass through this capsule. It is not surprising, therefore, that the morphological relationships between the follicle and the oocyte are of a highly specialized nature. Several workers have studied them, mainly by light microscopy, but their findings have not been unan...

To assess the association of zona pellucida micromanipulation and subsequent development of monozygotic twins, cases of assisted embryo hatching (AH) and intracytoplasmic sperm injection (ICSI) were identified and related to treatment type, implantation and zygosity data. Embryology records from all patients undergoing in-vitro fertilization (IVF) at this centre from January 1995 to March 1998 ...

Zona-free oocytes of the mouse were inseminated at prometaphase I or metaphase I of meiotic maturation in vitro, and the behavior of the sperm nuclei within the oocyte cytoplasm was examined. If the oocytes were penetrated by up to three sperm, maturation continued during subsequent incubation and became arrested at metaphase II. Meanwhile, each sperm nucleus underwent the following changes. Fi...

BACKGROUND Fertilization in mammals comprises the sequential interactions of the sperm with the cumulus oophorus, zona pellucida, and oocyte plasma membrane. Here we investigate proteasome activity in human sperm and its possible involvement during the fertilization process. METHODS Proteasome activity was measured in intact sperm and in sperm extracts using the fluorogenic substrate Suc-Leu-...

The extracellular matrix (ECM) of porcine mature oocytes was revealed by transmission electron microscopy (TEM) after treatment with tannic acid and ruthenium red. Present in the perivitelline space (PVS) and on the surface of the zona pellucida (ZP), it appeared to be composed of thin filaments and granules at the interconnections of the filaments, which were interpreted respectively as hyalur...

The causes of embryonic arrest during pre-implantation development are poorly understood. Attempts to correlate patterns of oocyte gene expression with successful embryo development have been hampered by the lack of reliable and nondestructive predictors of viability at such an early stage. Here we report that zygote viscoelastic properties can predict blastocyst formation in humans and mice wi...

Polymeric nanoparticles (NPs) are produced using bio-compatible and bio-degradable materials such as PLGA (Poly(lactic-co-glycolic acid)). This technology provides a valuable tool to deliver molecules the subcellular level with relatively low risk of cytotoxicity. However their use in field reproductive biotechnology is not yet scientifically substantiated. The aim present study was test if NPs...

1 The avian perivitelline layer, an extracellular matrix homologous to the zona pellucida 2 of mammalian oocytes, is composed mainly by zona pellucida gene family glycoproteins. 3 Our previous studies in Japanese quail have demonstrated that the matrix's components, 4 ZP3 and ZPD, are synthesized in ovarian granulosa cells. Another component, ZP1, is 5 synthesized in the liver. Recently, we dem...