The egg jelly of the starfish Asterias amurensis was separated into the fractions J1, J2, and J3 on a Sephadex G-100 column. The Jl fraction induced the acrosome reaction and J2 induced sperm agglutination. Chemical analysis and chromatography revealed that sperm agglutinin is similar to asterosaponin A.

Gene disruption experiments have proven that the acrosomal protein IZUMO1 is essential for sperm-egg fusion in the mouse. However, despite its predicted function, it is not expressed on the surface of ejaculated spermatozoa. Here, we report the dynamics of diffusion of IZUMO1 from the acrosomal membrane to the sperm surface at the time of the acrosome reaction, visualized using a fluorescent pr...

Oestrogens and 1α,25(OH)2-vitamin D3 (1,25-D3) are steroids that can provide effects by binding to their receptors localised in the cytoplasm and in the nucleus or the plasma membrane respectively inducing genomic and non-genomic effects. As confirmed notably by invalidation of the genes, coding for their receptors as tested with mice with in vivo and in vitro treatments, oestrogens and 1,25-D3...

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 ...

Sperm fertilization reactions of Limulus polyphemus were examined by scanning electron and/or light microscopy. The following were considered: sperm motility, attachment of sperm to egg, acrosome reaction, and penetration of the acrosomal filament. The spermatozoa after semination are non-motile and become active only in close proximity to a defined region surrounding the egg. Egg materials dif...

C-type natriuretic peptide (CNP) is a newly discovered type of local regulatory factor that mediates its biological effects through the specific, membrane-bound natriuretic peptide receptor-B (NPR-B). Recent studies have established that CNP is closely related to male reproductive function. The aims of this study were to determine the distribution of CNP/NPR-B in human ejaculated spermatozoa thr...

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)...

Introduction: Oxidative stress (OS) is an important factor in the etiology of male infertility which presents abnormal increase in the production of free radicals with negative influences on reproduction. The aim of present study is evaluation effect of mercury (Hg) (600& 1200 micro molar) and nicotine (0.75 mM), in vitro, on membrane integrity (LPO), GSH content, motility, and acrosome reactio...