Oocyte quality is the resultant of multifactor interactions that should be carefully taken into account either for in vitro embryo production technologies or for studying follicle dynamics. Different approaches may be used to perform an analysis of variables related to oocyte quality which may focus on the ovary, the follicle, the cumulus-oocyte complex and, finally, the oocyte. The information...

Wen-Shiun Yueh and Ching-Fong Chang (2000) Morphological changes and competence of maturing oocytes in the protandrous black porgy, Acanthopagrus schlegeli. Zoological Studies 39(2): 114-122. The study objectives aimed to investigate the morphological changes of oocytes during final oocyte maturation and ovulation, and the maturational competence of oocytes to respond to maturation-inducing ste...

Ovarian folliculogenesis is regulated by both endocrine and intraovarian mechanisms that coordinate the processes of oocyte growth and somatic cell proliferation and differentiation. Within the follicle, paracrine interactions between the oocyte and surrounding granulosa cells are critical for normal cell development and function. This review focuses on the role of paracrine interactions during...

Fertilization marks the end of oogenesis and the beginning of embryogenesis. The legacy of oogenesis is, however, maintained by virtue of the stored nutritional and regulatory molecules that fuel, and in many cases direct, early development. The signal that stimulates the transition from oocyte to embryo is a sperm-induced increase in the concentration of intracellular free Ca2+. Thus successfu...

Bicaudal-D (Bic-D) is essential for the establishment of oocyte fate and subsequently for polarity formation within the developing Drosophila oocyte. To find out where in the germ cells Bic-D performs its various functions we made transgenic flies expressing a chimeric Bic-D::GFP fusion protein. Once Bic-D::GFP preferentially accumulates in the oocyte, it shows an initial anterior localization ...

In vivo, histone H1 plays an active role in establishing the transcriptionally repressed chromatin state of the oocyte-type 5S RNA genes in the early stages of Xenopus development. By using fully defined in vitro system of chromatin assembly on plasmids with cloned oocyte- or somatic-type 5S gene repeats we found that the oocyte repeat which comprises a 120 bp oocyte-type 5S RNA gene placed wit...

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...

In the present study, various developmental stages of Liza aurata oocyte, especially IV and V stages have been described. On the basis of histological investigations, oocyte development in L. aurata comprises immature (I), the early maturing (II), the late maturing (III), mature (IV), ripe (V), and spent (VI) stages. In the stages I and II, nucleus occupied large volume of oocyte. Vacuolization...

It is known that amphibian oocytes undergo maturation through the formation and activation of maturation-promoting factor (MPF) in response to stimulation by the maturation-inducing hormone progesterone; however, the signal transduction pathway that links the hormonal stimulation on the oocyte surface to the activation of MPF in the oocyte cytoplasm remains a mystery. The aim of this study was ...

Vitrification method is widely used in oocyte cryopreservation for IVF but the birth rates are lower than that of the fresh oocyte. One of the known main reasons is structural instability of meiotic spindle and chromosome systems of mature oocyte. To get the best way for keeping competence of matured oocytes, we studied the best conditions for vitrification focused on equilibration times. The m...