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Enzymatic and inhibiting activity in boar epididymal fluid
Davidová, Nina ; Ren, Š. ; Liberda, J. ; Jonáková, Věra ; Maňásková-Postlerová, Pavla
Sperm maturation, represents a key step in the reproduction process. Spermatozoa, particularly the plasma membrane, are exposed to epididymal fluid (EF) components representing the natural environment essential for their post-testicular maturation. Changes in the sperm membrane proteins are influenced by proteolytic and glycosidic enzymes present in the EF. Accordingly, the occurrence of inhibitors in this reproductive organ is very important for the regulation of sperm membrane protein processing. In present study, we monitored protease and glycosidase activities, and inhibitors of metallo- and serine proteinases in boar EF. Additionally, we studied acrosin inhibitor in fluid, spermatozoa and tissue along the epididymis. We chromatographically separated boar EF into several fractions. These fractions were subjected to SDS-electrophoresis and the separated proteins were either studied by zymographic methods or transferred to nitrocellulose membranes for detection of metallo- and serine proteinases and their inhibitors, and acrosin inhibitor by specific antibody, respectively. Acrosin inhibitor was monitored also in the sperm and tissue of the boar epididymis. In boar epididymal fluid, several metallo- and serine proteinases with different molecular masses, and inhibitors of metalloproteinase MMP-9 and acrosin were found. We measured strong activity of mannosidase in this fluid. Using specific antibody, we registered the increasing signal of acrosin inhibitor from caput to cauda epididymis in the spermatozoa, fluid and also tissue. Proteinases and their inhibitors in reproductive fluids may play a significant role in reproduction processes. Especially, acrosin inhibitor in the reproductive tract inactivates prematurely released sperm acrosin and protects spermatozoa and reproductive epithelium against proteolytic degradation. High mannosidase activity in boar EF suggests evident role of mannose structures in the sperm interaction during reproductive events.
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Detection of mannosidase in the porcine urogenital tract – study of the sperm releasing from oviductal reservoir
Maňásková, Pavla ; Ren, Š. ; Jelínková, Jitka ; Krejčová, T. ; Liberda, J.
One of the most important steps of reproduction process is the meeting of sperm with oocyte. Binding of sperm with oviductal cells maintains spermatozoa in fertile state. The beginning of sperm capacitation is associated with oocyte ovulation resulting in the sperm release from oviductal reservoir. Hormonal changes after ovulation probably induce distinct oviductal secretion leading to disruption of the sperm protein binding with oviductal saccharide moieties. Another eventuality of the sperm releasing from oviductal reservoir is a change of oviductal environment caused by components of follicular fluid transported with oocyte after ovulation. In the pig, previous studies indicate lectin-type interaction of sperm protein receptors by mannose structures on the surface of oviductal cells. Our study was focused on enzymatic activity of mannosidase and its detection in porcine oviduct (fluid and tissue) and follicular fluid during hormonal cycle. In fluid from follicles in early and late hormonal stages, we measured mannosidase activity by colorimetric methods at physiological and acidic pH. Expression of secreted mannosidase was studied by specific antibody in follicular and oviductal fluids, and oviductal tissues during hormonal cycle. Clearly increased enzymatic activity of secreted mannosidase was found as specific-species in porcine fluid from follicles in late stage of hormonal cycle. On the other hand, detection of secreted mannosidase in follicular fluid as well as in oviductal fluid did not shown any significant differences during hormonal cycle. In oviductal isthmic tissue, we detected decreased protein expression of secreted mannosidase at middle and late follicular phases. These results suggest possible role of follicular mannosidase rather than oviductal one in the sperm releasing from oviductal reservoir in the pig. The additional study of the gene expression of secreted form of mannosidase in oviductal tissue during hormonal cycle should be necessary.
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