In the present study we describe the localization of proteasomes in human spermatozoa by means of immunolabelling with different monoclonal and polyclonal antibodies detected by confocal microscopy. Western blotting confirmed the specificity of the antibodies and has shown that proteasomes are present in spermatozoa and in seminal fluid. In spermatozoa proteasomes are concentrated in the neck r...

Compartmentalization of surface membrane antigens into discrete regions or domains is a characteristic feature of differentiated cells. In mammalian spermatozoa at least 5 surface domains are known, implying the presence of barriers or boundaries within the plasma membrane. Using the technique of fluorescence recovery after photobleaching (FRAP) to measure diffusibility of fluorescent lipid ana...

background: molecules expressed on the surface of infected erythrocytes (ie) with plasmodium falci-parum play important roles in malaria pathogenesis and immune evasion. some of these molecules are specific adhesive ligands mediating adhesion of ie to the vascular endothelium. in the current study, the antigens exposed on the surface of ie with different isolates and various binding subpopulati...

A solid-phase radioimmunoassay was developed for measuring the concentration of antispermatozoa antibodies in the sera of sterile patients. Whole human spermatozoa fixed in methanol and immobilized on plastic microtiter plates were used as antigens, and the spermatozoa-bound antibodies were quantitated with the aid of [125I]protein-A. The assay is specific, simple to perform and up to 1000 test...

Antisera to hCG were incubated with living human spermatozoa. Agglutination and complement-dependent immobilization of the spermatozoa occurred with the anti-hCG sera but not with control sera. The antisera also reacted with human blood cells. The anti-sperm activities were largely removed by absorbing the sera with human blood cells, although these absorptions had no apparent effect on the ant...

The detection of external cues is fundamental for human spermatozoa to locate the oocyte in the female reproductive tract. This task requires a specific chemoreceptor repertoire that is expressed on the surface of human spermatozoa, which is not fully identified to date. Olfactory receptors (ORs) are candidate molecules and have been attributed to be involved in sperm chemotaxis and chemokinesi...

Binding of mammalian spermatozoa to the zona pellucida of homologous eggs is mediated by specific molecules on their surface membranes. In the present investigation we describe the biogenesis, epididymal processing and cellular distribution of a plasma membrane antigen (2B1) on rat spermatozoa that has a potential role in mediating zona binding. 2B1 is expressed postmeiotically in the testis as...

Mammalian spermatozoa must undergo a post-ejaculatory period of maturation, known as capacitation, before they can engage in the process of fertilization. Studies in the mouse have established that capacitation facilitates sperm-zona recognition via mechanisms that involve the appearance of tyrosine phosphorylated chaperone proteins on the sperm surface overlying the acrosome, the site of sperm...

1. A method has been described for separation of heads and tails of mammalian spermatozoa. 2. By means of absorption technique applied to homologous spermatozoal sera, head-specific and tail-specific antigens could be demonstrated. Both are heat-labile. 3. A heat-stable antigen was found to be common to both heads and tails. This substance is species-specific. 4. Antibodies against the head- an...