background: the glycoconjugate content of sperms indicates their physiological and fertility properties. lectin reactivity is indicative of intact, capacitated, and acrosome-reacted sperms. in the epididymis, sperms experience maturation, glycoconjugate modification, and simultaneously, higher l-carnitine (lc) concentrations. the aim of this project was to evaluate the effects of lc and pentoxi...

In order to protect the spermatozoa against cold shock, hen egg yolk is widely used as a cryoprotective agent in semen freezing extenders for domestic animals. The protective action of yolk is largely presumed to be due to low density lipoproteins (LDL). The effects of LDL on sperm quality of bull and northern pike (Esox lucius) after freezing-thawing have been reported, but no study has been m...

The term membrane vesiculation is used in this report to denote the occurrence of multiple unions between two cellular membranes lying in close apposition, with the formation first of a double-walled fenestrated layer and ultimately of an array of separate membrane-bounded vesicles. The stages are illustrated in Fig. 1. The process depicted by these diagrams is essentially the same as that sugg...

We have previously defined distinct localizations of antigens on the surface of the guinea pig sperm using monoclonal antibodies. In the present study we have demonstrated that these antigen localizations are dynamic and can be altered during changes in the functional state of the sperm. Before the sperm is capable of fertilizing the egg, it must undergo capacitation and an exocytic event, the ...

Introduction This study evaluated whether post in vitro capacitation changes sperm could be used to estimate field fertility differences between bulls. Methods Frozen-thawed semen from five bulls (two four ejaculates per bull) previously identified as high (48.1% and 47.7%), intermediary (45.5%) or low (40.7% 43.1%) fertility, based on pregnancy AI (P/AI), were for total progressive motility, p...

Progesterone induces a biphasic Ca(2+) influx and consequent acrosome reaction in human spermatozoa. We have used two procedures to vary the stimulus (dosage and prior receptor desensitization) to investigate the encoding of stimulus strength by intracellular [Ca(2+)] ([Ca(2+)](i)). Acrosome reaction and amplitude (but not kinetics) of the transient [Ca(2+)](i) response (population measurement)...

to determine the effect of different levels of l-glutamine and glycerol on freezing coated sperm, semen were collected from 4 taleshi rams through artificial vagina contact with a tube containing tris-fructose-egg yolk 15%. ejaculates were pooled, centrifuged and supernatant was removed, then cell fractions were used. samples were split into 9 equal parts and 3 (g3), 5 (g5) or 7% (g7) glycerol ...

Capacitation and the acrosome reaction are key phenomena in mammalian fertilization. These phenomena were found more than 60 years ago. However, fundamental questions regarding the nature of capacitation and the timing of the acrosome reaction remain unsolved. Factors were postulated over time, but as their roles were not verified by gene-disruption experiments, widely accepted notions concerni...