Vertebrate female reproduction is limited by the oocyte stockpiles acquired during embryonic development. These are gradually depleted over the organism's lifetime through the process of apoptosis. The timer that triggers this cell death is yet to be identified. We used the Xenopus egg/oocyte system to examine the hypothesis that nutrient stores can regulate oocyte viability. We show that pento...

Genetic experiments suggest that polarization of the oocyte is linked directly to the initial cell fate determination that singles out the oocyte from its 15 sister cells. Specification of oocyte cell fate as well as establishment and maintenance of a polarized microtubule network within the Drosophila oocyte require the activity of the egalitarian (egl) and BicaudalD (BicD) genes. We have isol...

The 2,3,7,8-tetrachlorodibenzo-p-dioxin-inducible cytochrome P-450 gene family (P1-450 and P3-450 in the C57BL/6N mouse) has recently been localized to mouse chromosome 9. In the present study, HindIII-digested DNA from Chinese hamster, mouse, and 20 Chinese hamster X mouse somatic cell hybrids and subclones segregating hamster chromosomes was probed with the mouse P1-450 and P3-450 full-length...

Hamster sarcomas induced by the Gross pseudotype of Moloney sarcoma virus yielded a virus sarcomagenic for hamsters but not mice. This virus was able to produce foci on hamster embryo cells, but not on mouse embryo cells. A hamster-tropic nonfocus-forming helper virus was also found in the viral stocks. These hamster-tropic viruses are not immunologically related to the murine viruses in the or...

The poultry red mite Dermanyssus gallinae, known as the primarily ectoparasite of laying hens and synanthropic birds (e.g. pigeons), can also bite humans, causing Red-Mite Dermatitis (RMD) with untypical symptoms erythematous maculo-papular rash urticaria-like lesions. In this study, we present first case RMD diagnosed in a 12 year old boy, resulting from bites mites derived his pet hamster. re...

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...

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...