The adverse effects of maternal diabetes on embryo development and pregnancy outcomes have recently been shown to occur as early as the one-cell zygote stage. The hypothesis of this study was that maternally inherited mitochondria in oocytes from diabetic mice are abnormal and thus responsible in part for this latency of developmental compromise. In ovulated oocytes from diabetic mice, transmis...

The orthogonal axes of Drosophila are established during oogenesis through a hierarchical series of symmetry-breaking steps, most of which can be traced back to asymmetries inherent in the architecture of the ovary. Oogenesis begins with the formation of a germline cyst of 16 cells connected by ring canals. Two of these 16 cells have four ring canals, whereas the others have fewer. The first sy...

Over-nutrition in females causesaltered fetal growthduringpregnancy and permanently programs the metabolism of offspring; however, the temporal and mechanistic origins of these changes, and whether they are reversible, are unknown. We now show that, in obese female mice, cumulus-oocyte complexes exhibit endoplasmic reticulum (ER) stress, high levels of intracellular lipid, spindle abnormalities...

OBJECTIVE To evaluate DNA fragmentation in the oocyte of primordial and primary follicles and morphology of these follicles after freezing and thawing of ovarian cortex in sheep using two freezing protocols. DESIGN Fragmentation of DNA was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) technique. SETTING Fertility clinic in a large univ...

Dicer, which is required for the processing of both microRNAs (miRNAs) and small interfering RNAs (siRNAs), is essential for oocyte maturation [1, 2]. Oocytes express both miRNAs and endogenous siRNAs (endo-siRNAs) [3, 4]. To determine whether the abnormalities in Dicer knockout oocytes during meiotic maturation are secondary to the loss of endo-siRNAs and/or miRNAs, we deleted Dgcr8, which enc...

quality and quantity of ovum are major determinants in invitro fertilization. the aim of the present study was to determine effect of the time of oocyte collection and also distance of hcg injection to oviduct flushing on the quantity, quality and fertilizing ability of rabbit oocyte. accordingly, sixty two adult female rabbit selected and randomly allocated to seven groups. the rabbits were su...

In the process of oocyte maturation, gonadotrophins are believed as main stimulators for oocyte meiosis resumption. However, which gonadotrophin (i.e. FSH or LH) is the key hormone in this process is still unknown. This study indicated a close relationship between LH and FSH on activating meiotic maturation of oocyte in vitro. FSH efficiently induced oocyte meiosis at concentration of 50 IU/L, ...

The formation of yolk spheres in the oocyte of the cecropia moth, Hyalophora cecropia (L.), is known immunologically to result largely from uptake of a sex-limited blood protein. Recent electron microscope analyses of insect and other animal oocytes have demonstrated fine structural configurations consistent with uptake of proteins by pinocytosis. An electron microscope analysis of the cecropia...

The PAR-1 kinase is required for the posterior localisation of the germline determinants in C. elegans and Drosophila, and localises to the posterior of the zygote and the oocyte in each case. We show that Drosophila PAR-1 is also required much earlier in oogenesis for the selection of one cell in a germline cyst to become the oocyte. Although the initial steps in oocyte determination are delay...

Mammalian reproduction hinges upon the timely ovulation of a fully differentiated oocyte. This event is the culmination of a complex and dynamic developmental relationship between the oocyte and the antral follicle housing it; the antral follicle constitutes a specialized microenvironment or niche, uniquely suited to the needs of the oocyte as it approaches ovulation. During this time, the oocy...