Intracellular free calcium concentration in the sea urchin egg was calculated to increase from 0.1 mM in an unfertilized egg to 1 mM in a fertilized egg 10 min after fertilization, based on measurement of the dissociation constant between free calcium and sea urchin egg homogenate. The dissociation constant between free calcium (dialyzable calcium) and homogenate of sea urchin eggs was measured...

Intracellular Ca(2+) oscillations at fertilization are responsible for triggering egg activation. The aim of this study was to examine the effect of the age of the oocyte donor and in-vitro maturation on the generation of Ca(2+) transients at fertilization. The results show that <10% of in-vivo and in-vitro matured oocytes from 19-day old mice develop to the blastocyst stage in vitro. In contra...

Oocyte maturation in rodents is characterized by a dramatic reorganization of the endoplasmic reticulum (ER) and an increase in the ability of an oocyte to release Ca(2+) in response to fertilization or inositol 1,4,5-trisphosphate (IP(3)). We examined if human oocytes undergo similar changes during cytoplasmic meiotic maturation both in vivo and in vitro. Immature, germinal vesicle (GV)-stage ...

Self-fertilization occurs in a broad range of hermaphroditic plants and animals, and is often thought to evolve as a reproductive assurance strategy under ecological conditions that disfavour or prevent outcrossing. Nevertheless,selfing ability is far from ubiquitous among hermaphrodites, and may be constrained in taxa where the male and female gametes of the same individual cannot easily meet....

Despite the well-known benefits of omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation on human health, relatively little is known about the effect of n-3 PUFA intake on fertility. More specifically, the aim of this study was to determine how oocyte and preimplantation embryo development might be influenced by n-3 PUFA supply and to understand the possible mechanisms underlying thes...

Background: During spermatogenesis the sperm nucleus exchange histones against cystein rich protamines, which stabilize the sperm chromatin and protects the DNA against damages. At ejaculation the age of the patient, handling routines, processing of the semen sample and the storage of the final sperm suspension might damage the DNA. Sperm chromatin stability and DNA damages are evaluated with d...

The generation of novel hybrid lines is critically limited by the compatibility between pollen and pistil and their ability to achieve successful seed formation. Fertilization in flowering plants requires the successful transfer of the male gametes from the pollen grain to the egg contained within an ovule. This occurs via the formation of a tubular protrusion from the pollen grain – the pollen...

Spermatozoa normally encounter the egg at the fertilization site (in the Fallopian tube) within 24 hr after ovulation. A considerable fraction of the spermatozoa ejaculated into the female reproductive tract of mammals remains motionless in storage sites until ovulation, when the spermatozoa resume maximal motility and reach the fertilization site within minutes. The nature of the signal for sp...

The silkworm, Bombyx mori, has a dimorphic sperm system. The eupyrene sperm is the sperm to fertilize eggs and the apyrene sperm plays a crucial role for assisting fertilization. Heat-treated (33 degrees C for 96h) Daizo (DH) males, one of the strains in the silkworm, produce only eupyrene sperm, while in triploid males only apyrene sperm are functional. Though both types of males are found to ...