Keeping the intact germinal vesicle (GV) is essential for maintaining the capacity of mammals including human. It is maintained by very complex procedures along with folliculogenesis and is a critical step for getting competent oocyte. So far, a few mechanisms involved in folliculogenesis are known but GV arrest mechanisms are largely unrevealed. Cyclic AMP, a adenosine derived substance, have been used as inhibitor of germinal vesicle breakdown as a putative oocyte maturation inhibitor. In this study, we examined the potency of adenosine as GV maintainer and a possible signaling mediator for that. A1, A2b, and A3 were detected in cumulus cells of cumulus enclosed-oocyte (CEO). Intact of germinal vesicle was not kept like in follicle but the spontaneous maturation was inhibited by exogenous adenosine. It is inhibited with concentration dependent manners. Intracellular calcium level of cumulus was extensively increased after adenosine treatment. Based on these results it is suggested that one of the pathway for GV arrest by adenosine and its receptors is calcium mediated signaling pathway in CEO.

Egg activation is a crucial step that initiates embryo development upon breaking the meiotic arrest. In mammalian, egg activation is accomplished by fusion with sperm, which induces the repeated intracellular - increases ( oscillation). Researches in mammals support the view of the oscillation and egg activation is triggered by a protein factor from sperm that causes release from endoplasmic reticulum, intracellular store, by persistently activation of phosphoinositide pathway. It represents that the sperm factor generates production of inositol trisphosphate (). Recently a sperm specific form of phospholipase C zeta, referred to as PLCZ was identified. In this paper, we confer the evidence that PLCZ represent the sperm factor that induces oscillation and egg activation and discuss the correlation of PLCZ and infertility.

Cold acclimation of plants is a highly active process resulting from the expression of a number of physiological and metabolic adaptations to low temperature. Major metabolic changes in carbohydrates, protein, nucleic acids, amino acids, and growth regula

Befor fertilization, mammalian oocytes undergo meiotic maturation, which consists of nuclear and cytoplasmic differentiation. In this study, changes of stores in mouse oocytes were examined during meiotic maturation and the role of in the regulation of the maturation was investigated by using monoclonal antibodies against smooth endoplasmic reticulum -ATPase(SERCA-ATPase) and calreticulin. Observations were made under epifluorescence microscope and/or confocal laser scanning microscope. In immature oocytes which did not resume meiotic maturation, SERCA-ATPases were mostly localized in the vicinity of the germinal vesicle and calreticulins were distributed evenly throughout the cytoplasm. In mature oocytes, SERCA-ATPases were observed throughout the cytoplasm, butwere absent from the nuclear region. In contrast, calreticulins were localized mostl in the cortex of the oocyte and were absent from the cytoplasm. However, bright fluoresence stainings were wbserved in the perimeiotic spindle region of mature oocyte when labeled with antibodies against calreticulin. These results indicate that mouse oocytes undergo distinct rearrangement of the localization of -ATPases and calreticulins during meiotic maturation. Thus it can be suggested that redistribution of the stores, as revealed by differential fluorescence stainings, is deeply involved in the regulatory mechanism of mammalian oocyte maturation.