"Capacitation" is a physiological event which alters sperm to permit rapid penetration through oocyte investments and fusion between gametes. Acrosomal "reaction," the physiological release of acrosomal contents, occurs after this facilitating process. In this study, acrosomal "disruption" of guinea pig and rat sperm was achieved in vitro by incubating sperm together with the follicular content...

Zona-free oocytes of the mouse were inseminated at prometaphase I or metaphase I of meiotic maturation in vitro, and the behavior of the sperm nuclei within the oocyte cytoplasm was examined. If the oocytes were penetrated by up to three sperm, maturation continued during subsequent incubation and became arrested at metaphase II. Meanwhile, each sperm nucleus underwent the following changes. Fi...

OBJECTIVE In assisted reproduction, spermatozoa must be effectively separated from seminal plasma to undergo capacitation, a prerequisite for fertilization. Percoll was recently withdrawn from the American market because of safety concerns. The purpose of this study was to evaluate the quality of sperm separated by two different sperm washing media, and compare these results to sperm quality af...

The aim of this study was to investigate whether the quality of semen has deteriorated during the last decade. Laboratory records containing semen analysis results were reviewed. The records, arranged according to date of birth, are kept in shelves. Every fifth record for analyses performed between 1985 and 1995, and only those of men in infertile relationships, were included. The data were abs...

We perform Large eddy simulations of turbulent compressible convection in stellar-type convection zones by solving the Naviér-Stokes equations in three dimensions. We estimate the extent of penetration into the stable layer above a stellar-type convection zone by varying the rotation rate (Ω), the inclination of the rotation vector (θ) and the relative stability (S) of the upper stable layer Th...

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...

F or successful mammalian fertilization, sperm penetrate the outer investments of female gametes in the ampulla of the oviduct and fuse with the egg plasma membrane. The “fertilizing” sperm traverse the cumulus mass surrounding ovulated eggs, bind temporarily, and then penetrate through the zona pellucida, a structured extracellular glycomatrix, to enter into the perivitelline space (Fig. 1A). ...

Calcium flux is required for the mammalian sperm acrosome reaction, an exocytotic event triggered by egg binding, which results in a dramatic rise in sperm intracellular calcium. Calcium-dependent membrane fusion results in the release of enzymes that facilitate sperm penetration through the zona pellucida during fertilization. We have characterized inositol 1,4,5-trisphosphate (IP3)-gated calc...

Current industry estimates of reproductive performance for cattle, sheep, and swine operations indicate that males contribute significantly to fertility failures. This appears to be due to the use of subfertile individuals and emphasizes the need for additional research in identifying characteristics of sperm that compromise fertilization. In theory, sperm characteristics, such as motility or t...