Both Neodiplogaster pinicola and Panagrellus redivivoides reproduce amphimictically, with XO type of sex determination. In N. pinicola, primary spermatocytes have six bivalent chromosomes and one univalent; after two meiotic divisions, sperm are produced with either six or seven chromosomes. In primary oocytes, with seven bivalents, meiosis is initiated by entrance of a sperm. After two meiotic...

Frog eggs are normally fertilized after reaching metaphase II. When eggs are inseminated prior to that, several sperm enter, but entry does not activate the egg. When such inseminated, immature eggs were maintained until they became mature and then were artificially activated, the eggs began to cleave. The cleavage furrows were irregular and often multiple, but the eggs developed to blastulae o...

The cryoprotective effects of glycerol in three different semen freezing extenders, Tris-citrate (TRIS), TEST, and Tes-Tris-Egg yolk (TTE), on wild-type (WT) rhesus monkey (Macaca mulatta) sperm cryopreservation have been tested. Sperm motility and viability were examined to evaluate the integrity of frozen-thawed sperm, and the best extender was selected to cryopreserve sperm from transgenic H...

sperms are highly specialized cells for delivering dna from male to the ovum. incredibly, wide degree of diversity in sperm morphology in their basic structures i.e. head, middle piece and tail is found across species. differences in terms of overall size of the sperm, shape and number of sperm produced are also incredible. one of the key for this variations or diversity in sperm may be associa...

Intrauterine insemination (IUI) as a type of artificial insemination involves the placement of sperm directly into the uterus at the time of ovulation, either in a natural menstrual cycle or following ovarian stimulation. The process allows the concentration of sperm in a small volume of culture media and then the concentrated sperm is placed into the uterus through a transcervical catheter. IU...

Mitochondria, important energy centers in the cell, also control sperm cell morphogenesis. Drosophila spermatids have a remarkably large mitochondrial formation called the nebenkern. Immediately following meiosis during sperm development, the mitochondria in the spermatid fuse together into two large aggregates which then wrap around one another to produce the spherical nebenkern: a giant mitoc...

Intrauterine insemination (IUI) as a type of artificial insemination involves the placement of sperm directly into the uterus at the time of ovulation, either in a natural menstrual cycle or following ovarian stimulation. The process allows the concentration of sperm in a small volume of culture media and then the concentrated sperm is placed into the uterus through a transcervical catheter. IU...

In plants, each male meiotic product undergoes mitosis, and then one of the resulting cells divides again, yielding a three-celled pollen grain comprised of a vegetative cell and two sperm cells. Several genes have been found to act in this process, and DUO1 (DUO POLLEN 1), a transcription factor, plays a key role in sperm cell formation by activating expression of several germline genes. But h...

Dopamine is a catecholamine with multiple physiological functions, playing a key role in nervous system; however its participation in reproductive processes and sperm physiology is controversial. High dopamine concentrations have been reported in different portions of the feminine and masculine reproductive tract, although the role fulfilled by this catecholamine in reproductive physiology is a...

Male factor infertility accounts for approximately 50 percent of infertile couples. The male factor-related causes of intracytoplasmic sperm injection failure include the absence of sperm, immotile sperm, immature sperm, abnormally structured sperm, and sperm with nuclear damage. Our knockout and knock-in mice models demonstrated that SEPTIN12 (SEPT12) is vital for the formation of sperm morpho...