SPERM PENETRATION OF PIG EGGS IN UTERO

Sperm Penetration of the Zona Pellucida of the Pig Egg.

In most mammals that have been studied, the first spermatozoon which penetrates an egg stimulates the egg to undergo a reaction—the 'zona reaction'—which bars further spermatozoa from penetrating through the zona pellucida (Braden, Austin & David, 1954). The sequel to the zona reaction may be classified into two categories, according to species: species in which spermatozoa are entirely prevent...

Sperm and scrambled eggs

A newspaper obituary not long ago revealed that its subject was believed to have been both the son and grandson of the lecherous monarch, Edward VII. (Work it out for yourself.) But this is as nothing to the conundrums that Lee Silver sets out in his mesmerizing vision of our genetic future. Within weeks of the eruption of Dolly the sheep into the pages of Nature — and regardless of the doubts ...

Utero-ovarian relationships in the guinea pig.

Observations on Sperm Penetration in the Rat

The structural aspects of sperm penetration in the rat egg were investigated by electron microscopy. Eggs were recovered at intervals between 8 and 10:30 A.M. from females which had mated during the previous night. The oviducts were flushed with hyaluronidase and the eggs transferred into a 2 per cent osmium tetroxide solution, buffered at pH 7.8. After fixation, the eggs were mounted individua...

Quantitative sperm mucus penetration: modified formulae for calculating penetration efficiency.

In 1980 Katz et al. derived a formula for the percentage of successful collisions (PSC) as a quantitative measure of sperm-cervical mucus penetration efficiency. The use of PSC waned after its validity was questioned by reports of values >100% and the observation that PSC varied with the cross-sectional area of the mucus column. The aim of the present study was to develop a more accurate measur...