Sperm plasma membrane

About: Sperm plasma membrane is a research topic. Over the lifetime, 1016 publications have been published within this topic receiving 49964 citations.

Sperm surface immobilization isoantigens

Abstract: Publisher Summary This chapter focuses on sperm surface immobilization isoantigens. Immobilization antigens, which occur on epididymal, ejaculate, and capacitated spermatozoa but are not necessarily isoantigens, are localized on sperm head and tail regions. In the case of a single, isolated immobilization antigen, the antigen is masked by seminal plasma coating antigens on ejaculate spermatozoa. Within the class of intrinsic sperm plasma membrane isoantigens, at least one is transferred from the sperm to the egg's plasma membrane during fertilization. Unfertilized, ovulated eggs do not lyse in the presence of sperm-specific isoantiserum and complement. However, following fertilization, the zygote is lysed by sperm immobilizing isoantiserum and complement. Sperm isoantigens, distinguished by the immobilization reaction, first appear on the cell surface at approximately the time spermatogenic cells migrate across the blood–testis barrier. From this stage onward, they are continually present until fertilization when at least one is transferred to the egg. As new synthesis of antigen cannot be expected until after sexual maturation of the male, the transferred isoantigens are lost during subsequent embryogenesis.

Investigation of progesterone receptor on human sperm plasma membrane

Abstract: OBJECTIVES To investigate the localization and positive percentage of progesterone receptor (PR) on the human sperm surface. METHODS After in vitro capacitation, progesterone binding sites on the sperm were quantitatively analyzed by fluorescence microscopy and flow cytometry using fluorescein isothiocyanate-labeled bovine serum albumin-progesterone complex (P-BSA-FITC). RESULTS The spermatozoa stained by P-BSA-FITC mainly showed two labeling patterns, with the green fluorescence on the whole acrosomal region or the equatorial acrosomal region only and the stainless postacrosomal and tail regions. The percentage of progesterone-binding sperm was (30.2 +/- 2.4)%. CONCLUSIONS There is selective expression of PR on the human sperm acrosome surface.

Sperm binding properties to uterine epithelial cells in vitro employing a primary porcine endometrium culture system

Abstract: In pig husbandry the conventional method of intrauterine deposition of an 80-100 ml AI volume containing 1-3 x109 fresh spermatozoa is the commonly used procedure. Compared to bovine insemination, where as little as 2 x106 spermatozoa result in gravities, boar ejaculates have only little efficiency. The only way to utilize low doses of boar sperm is to deposit the semen closer to the site of fertilisation, which is in the distal isthmus of the oviduct. The species-specific binding of spermatozoa, to several surface epithelia in the female tract, foregoing capacitation and hyperactivation, encompasses carbohydrate recognition by lectin-like receptors on the sperm plasma membrane. It was therefore assumed that the putative binding of porcine sperm and uterine epithelia is mediated by specific protein-carbohydrate interactions, too. The aim of this thesis was to establish a reproducible in vitro cell culture model from primary uterine epithelial cells of the sow (Sus scrofa) to examine and identify possible reasons for the high numbers needed in porcine fertilisation. Porcine uterine epithelial cells were harvested by layer-enzymatic digestion with Trypsin/EDTA (1x). Dissemination was carried out on collagen (rat tail, type I) coated glass cover slips in six-well culture dishes. Cells started to adhere to the collagen matrix after 12 to 36 hours and colonies were formed after five to seven days. Confluence could be documented after ten to 15 days. Verification for epithelial cells was completed by immune-fluorescence antibody stain using an epithelial cell-specific primary antibody (marking cytokeratin 19). Porcine spermatozoa bound to UEC within minutes and remained motile. Reduced sperm binding was observed for sperm on porcine aortal epithelia as well as porcine foetal fibroblasts, indicating that porcine uterine epithelia possess specific ligands for porcine sperm surface moieties. Sperm as well as uterine epithelia showed high binding density for lectins affine for Glc-NAc and sialic acid as well as Gal-NAc indicated by high binding intensities from lectins affine for these oligosaccharides, namely wheat germ agglutinin (WGA) and succinylated wheat germ agglutinin (sWGA). The blocking of sialic acid residues on the UEC before sperm incubation resulted in diminished binding density. No effect was seen for blocked Glc-NAc ligands. This shows that the main molecule involved in sperm-UEC interactions most likely is sialic acid.

Effect of season on semen quality parameters in Murrah buffalo.

Abstract: Seasonal influence on frozen semen quality in Murrah buffalo breeding bulls was determined. Frozen semen samples of 6 Murrah buffalo bulls were collected and semen frozen in 4 different seasons, viz. winter (Dec-Feb), spring (mid Feb-Apr), summer (May-Jun) and rainy (Jul-Aug) were assessed. Samples (12) of each bull, in a season, were evaluated for sperm motility, viability and acrosome integrity. Motility and other kinematics of spermatozoa during incubation (37°C) at 0, 30, 60, 90 and 120 min of thawing were assessed with computer assisted semen analyzer. Post-thaw sperm total motility and viability differed significantly among the seasons, the highest was in winter. Sperm plasma membrane integrity, acrosome integrity, progressive motility, rapid motility and other CASA evaluated parameters did not differ significantly among the seasons. Higher values of plasma membrane integrity (PMI), progressive motility, rapid motility, average path velocity (VAP), straight line velocity (VSL), curvilinear velocity (VCL), beat cross frequency (BCF), linearity (LIN) and straightness (STR) were obtained in winter season as compared to other seasons. Post-thaw motility at 0 min and 60 min of post-thaw incubation varied significantly between seasons and higher sperm motility was sustained for a longer period in semen cryopreserved in winter followed by rainy season, summer and spring. It can be concluded from this study that buffalo bull semen produced and frozen during winter season resulted in higher sperm motility, viability and postthaw longer survivability in comparison to other seasons.

Original research article Comparative study on the spermicidal activity of organic solvent fractions from hydroethanolic extracts of Achyranthes aspera and Stephania hernandifolia in human and rat sperm

Abstract: Background: This study was conducted to determine the most effective fraction of the hydroethanolic (water:ethanol, 1:1) extracts of Stephania hernandifolia leaves and Achyranthes aspera roots (in a composite manner at a ratio of 1:3, respectively) that will provide maximum spermicidal activity in human and rat spermatozoa out of five different ratios (1:1, 1:3, 1:7, 3:1 and 7:1) that have been studied in pilot experiments. Study Design: n-Hexane, chloroform and ethyl acetate fractions of the hydroethanolic (1:1) extracts of S. hernandifolia and A. aspera were mixed at 1:3. Different concentrations were tested for sperm immobilization, sperm viability, acrosome status, 5′-nucleotidase activity and nuclear chromatin decondensation using human and rat spermatozoa for the selection of the most effective concentration. Results: Out of three fractions of the hydroethanolic (1:1) extracts of the said plants, the n-hexane fraction was most effective, and the chloroform fraction exhibited minimum activity for this purpose. At a concentration of 0.1 g/mL hexane fraction, all sperm of the human sample were immobilized immediately (within 20 s). In case of the rat sample, all epididymal spermatozoa were immobilized immediately (within 20 s) by treatment with hexane fraction at a concentration of 0.004 g/mL. All human sperm were found to be nonviable within 20 min. The activity of acrosome enzymes was reduced, and significant release of 5′-nucleotidase (a plasma membrane marker) into the surrounding medium was noted after treatment with 0.1 g/mL hexane fraction, indicating that the hexane fraction affected the cytoarchitecture of the sperm plasma membrane. The maximum number of human sperm failed to decondense when treated with 0.1 g/mL hexane fraction, and sperm motility was also irreversible. The hexane fraction was tested in rats as vaginal contraceptive and showed 100% efficacy, indicating its potential for development as vaginal contraceptive. Conclusion: The findings indicate that, among the different fractions, the hexane fraction of the hydroethanolic extracts of the two plants produced the most effective spermicidal activity and can be considered as vaginal contraceptive.