Ovulated eggs possess maternal apoptotic execution machinery that is inhibited for a limited time. The fertilized eggs switch off this time bomb whereas aged unfertilized eggs and parthenogenetically activated eggs fail to stop the timer and die. To investigate the nature of the molecular clock that triggers the egg decision of committing suicide, we introduce here Xenopus eggs as an in vivo sy...

Ovulation in European eel is induced by injection of 17α,20β-dihydroxy-4-pregnen-3-one (DHP) as the maturation-inducing hormone (MIH). Female eels need to ovulate within 18 h after release good quality eggs. Progesterone (P), an upstream precursor DHP, may promote endogenous DHP production and improve egg quality. The purpose this study was therefore compare treatment P with on batch level, vit...

EGG maturation in Limnaea stagnalis has been described by Raven (1945, 1949). It exhibits some peculiarities, by which the Limnaea egg seemed to stand apart from all other animal eggs in which the maturation processes have been accurately studied so far. In the first place it appeared that the second maturation spindle arises by a direct and gradual transformation of the centrosphere at the inn...

BACKGROUND Patients with mutations that inactivate kisspeptin signaling are infertile. Kisspeptin-54, the major circulating isoform of kisspeptin in humans, potently stimulates reproductive hormone secretion in humans. Animal studies suggest that kisspeptin is involved in generation of the luteinizing hormone surge, which is required for ovulation; therefore, we hypothesized that kisspeptin-54 ...

The effect of streptozotocin-induced diabetes mellitus was studied in mice infected with Schistosoma mansoni. Faecal egg excretion was lower in diabetic mice but worm load and total amount of eggs in the intestine tissue were equal to the control group. Evaluation of an oogram showed a great number of immature dead eggs and a low number of mature eggs in diabetic mice. It was therefore conclude...

Background: Assisted fertilization procedures are a currently widespread practice to regulate reproduction in humans and animals. The arising question is why the human being manipulating gametes to generate new individuals, if we do not understand yet the molecular mechanism of fertilization?. Successful completion of fertilization in mammals is dependent on three membrane fusion events: 1. the...

the interaction between molecular biology and embryology made an extensive progress in the research on gametogenesis, fertilization and early embryogenesis in mice. in this article, molecules involving in meiotic maturation and apoptosis of oocytes, sperm-oocyte interactions and early cleavage of fertilized embryos in mice are described including our recent following experiments. 1) phosphatidy...

Attempts on artificial maturation of European eel (Anguilla anguilla) have largely been unsuccessful. The moment of stimulation of final maturation and ovulation is mainly based on weight increase related to the hydration response of the oocytes, which, in the European eel, is irregular. In contrast to Japanese eel, European eels show wide individual variability and much slower response to horm...

A sperm-induced intracellular Ca2+ signal ([Ca2+]i) underlies the initiation of embryo development in most species studied to date. The inositol 1,4,5 trisphosphate receptor type 1 (IP3R1) in mammals, or its homologue in other species, is thought to mediate the majority of this Ca2+ release. IP3R1-mediated Ca2+ release is regulated during oocyte maturation such that it reaches maximal effective...