Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Vitro binding and some binding parameters of the glycosaminoglycan heparin to viable epididymal or ejaculated bull spermatozoa, ejaculated rabbit spermatozoa, and frozen-thawed rhesus monkey spermatozoa were investigated. Nonspecific binding was affected only by the concentration of 3H-heparin, whereas specific binding was saturable, reversible, and dependent on the pH, temperature, and calcium concentration of the incubation medium. Magnesium concentration dependence was observed in the presence of calcium but could not be detected in the absence of calcium. Bound 3H-heparin was displaced by several orders of magnitude greater concentrations of chondroitin sulfate. Scatchard plot analysis suggested multiple binding affinities for 3H-heparin to spermatozoa. 3H-heparin was shown to bind to sperm heads and flagella. Fluorescein-labeled heparin bound to acrosomal, postacrosomal, and flagellar membranes. It was concluded that the specific binding of heparin involved a proteinaceous component on, or intercalated with, spermatozoal membranes. Thus, glycosaminoglycans present in the female reproductive tract may contribute to sperm capacitation and enhance the likelihood of successful fertilization in mammals.
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PMID:Specific binding of the glycosaminoglycan 3H-heparin to bull, monkey, and rabbit spermatozoa in vitro. 671 57

Fluorescein and carboxyfluorescein have found recent application as probes of intracellular pH. The present study examines several parameters required for interpretation of the spectral information derived from fluorescein and carboxyfluorescein generated intracellularly from their permeant diacetate derivatives. Coefficients were determined for the pH dependence of the difference absorbance, of the absorbance ratios, and of the fluorescence emission intensity ratios at selected wavelength pairs for carboxyfluorescein in aqueous buffers. The effect of light scattering on the apparent pH reported by carboxyfluorescein in dilute cell suspensions was assessed. An apparent intracellular acidification associated with increasing internal dye concentration was found to result probably from interactions of the intracellular probe with itself. Working within the experimental limitations imposed by these considerations, protocols utilizing either direct measurement of absorbance or fluorescence or determination of the null spectral response observed upon release of internal carboxyfluorescein all indicate that the cytosolic space of bovine epididymal sperm is maintained at pH 6.5-6.6. The monovalent-cation-specific, carboxylic acid ionophores, nigericin and monensin, were utilized to produce transmembrane proton gradients in cells that were allowed to generate intracellular carboxyfluorescein in a preliminary incubation, then resuspended in media buffered at the same pH as the sperm cytosol but of varying cation composition. By interpolation to the null response, the initial internal Na+ and K+ concentrations in bovine sperm were estimated as 14 +/- 2 and 120 +/- 5 mM, respectively. The ability of initial transmembrane gradients of either protons or of monovalent cations to promote equivalent changes in internal pH following ionophore addition to sperm suspensions supports application of a simple model that predicts steady state cation distributions. With the assumption that the cytosolic proton buffer has a pKa near the determined internal pH, these experiments allow the additional calculation that this buffer is present at a concentration of 190 +/- 20 meq/liter in the bovine sperm.
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PMID:Examination of the intracellular ionic environment and of ionophore action by null point measurements employing the fluorescein chromophore. 685 88

We have examined the epididymal (caput, corpus and cauda) and ejaculated spermatozoa of bufallo-bull (Bubalus bubalis) employing microscopic and spectroscopic techniques. Fluorescein isothiocyanate conjugated lectins namely concanavalin A (Con A), Dolichos biflorus (DBA), Maclura pomifera (MPA), peanut agglutinin (PNA), soybean agglutinin (SBA) and wheat germ agglutinin (WGA) were used to study the changes in the sperm surface carbohydrate make up as the spermatozoa mature. Quantitative analysis of the lectin binding was made flow cytometrically. 31P-NMR (nuclear magnetic resonance) spectra of the sperms obtained from different regions (head, body and tail) of the epididymis and of the ejaculate were analyzed to assess their metabolic activity. And the kinetics of spin label reduction of these samples was monitored with ESR (electron spin resonance) spectroscopy. These observations are supplemented with the electron microscopic (SEM and TEM) examination of the epididymal and ejaculated spermatozoa.
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PMID:Spectroscopic and microscopic studies of buffalo-bull (Bubalus bubalis) spermatozoa. 838 30

Plasma membrane alterations accompanying in vitro capacitation and acrosome reaction of goat spermatozoa were studied using lectin labelling, scanning electron microscopy, and freeze-fracture methods. Fluorescein isothiocyanate linked lectins namely; Canavalia ensiformis (ConA), Maclura pomifera (MPA), Arachis hypogaea (PNA), Glycine max (SBA) and Triticum vulgaris (WGA) agglutinin were used to examine the distribution of surface carbohydrates during these two events. The head and the sperm tail reveal altered lectin labelling features after capacitation and acrosome reaction. After capacitation the surface coat components for MPA, SBA, and WGA are shed from the spermatozoon head. ConA receptors on the head are retained after capacitation but are partially shed in the acrosome reacted spermatozoa. SBA receptor sites appear on the sperm tail of the capacitated spermatozoa. Unusual morphological changes attending capacitation involve the sperm tail-end which develops a novel entity, which we have termed 'spatula'. The 'spatula' shows strong binding with ConA and WGA only. In the acrosome reacted spermatozoa the spatulated tail-end unwinds with a concomitant loss of lectin labelling. Highly ordered membrane particles, 'ladders' of the middle piece of the epididymal sperm tail, disappear and IMP clearings appear on the middle piece and in the spatulated ends of the capacitated spermatozoa. But in the acrosome reacted sperm IMPs reappear and are randomly disposed on the middle-piece and are clustered in small patches on the principal-piece. IMP free areas appear on the plasma membrane covering the acrosome and the outer acrosomal membrane (OAM) of the capacitated spermatozoa. The plasma membrane and OAM fuse at multiple foci and appear as acrosomal 'ghosts' which remain associated with the sperm head even after acrosome reaction.
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PMID:Capacitated and acrosome reacted spermatozoa of goat (Capra indicus): a fluorescence and electron microscopic study. 851 52

In the present study, we assessed the presence of the ATP-binding-cassette (ABC) transporter molecules ABCA1 in spermatozoa of adult stallions and in testicular and epididymal tissue of prepubertal and adult stallions. For this purpose, semen samples from six fertile Shetland pony stallions aged 4 to 19 years were collected. Semen was collected from each stallion on three consecutive days. Ejaculates were analyzed immediately after collection, and only ejaculates meeting minimal requirements for fertile stallions were further evaluated. ABCA1 immunosignal was localized after staining of semen smears with different antibodies and counterstaining with Fluorescein isothiocyanate (FITC)-peanut agglutinin (PNA) and 4',6-Diamidin-2-phenylindol (DAPI). In a total of three samples, capacitation and acrosome reaction were induced by means of capacitation medium and progesterone substitution, respectively. Testicular and epididymal tissues were obtained from five prepubertal stallions aged 8 to 12 months and five adult stallions aged 4 to 9 years. For quantitative RT-PCR (qPCR), testicular and epididymal tissue of another seven adult (aged 1.5-14.5 years) and five prepupertal stallions (6-8 months) was used. For immunohistochemistry, sections from the caput, corpus, and cauda of the testes and epididymes were stained with the same specific antibodies as for immunocytochemistry. In stallion spermatozoa, strong immunosignal for ABCA1 was detected in the acrosomal area, the equatorial zone, and the principle piece of the flagellum but not in the caudal part of the head and the midpiece. In damaged or acrosome-reacted spermatozoa the FITC-PNA signal vanished together with the ABCA1 signal in most spermatozoa. In testicular tissue, strong immunostaining for ABCA1 was mainly visible in the heads and flagella of round spermatids and weaker signals in late spermatids and released spermatozoa. No staining was assessed in the Sertoli cells and spermatogonia of adult stallions, whereas strong signals in Leydig cells were present in prepubertal stallions. In prepubertal stallions, the ABCA1 messenger RNA level in testicular tissue was significantly higher than in adult stallions. We conclude that the ABCA1 transport molecule is present in adult and prepubertal stallion spermatozoa as well as testicular and epididymal tissue. ABCA1 is supposed to contribute to cholesterol transport and to support capacitation; however, this remains to be proven by functional studies. Species-specific differences concerning the localization inside the spermatozoa membrane are alike.
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PMID:The cholesterol transporter ABCA1 is expressed in stallion spermatozoa and reproductive tract tissues. 2671 2