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)

When rabbit sperm were pretreated with media of high ionic strength (380 mOsM), which had previously been shown to facilitate removal of sperm-bound seminal plasma components, and subsequently treated with follicular fluid the acrosome reaction was completed rapidly. Treatment of the sperm with follicular fluid alone yielded a greatly decreased rate of acrosome reaction completion, and treatment with the high-ionic strength medium alone caused no visible alteration to the sperm. These results suggest that removal of the sperm-bound seminal plasma components destabilizes the acrosome and prepares it to undergo the acrosome reaction. This destabilization is virtually completed after a 5-minute preincubation of the sperm in high-ionic strength media. Direct comparison of epididymal and ejaculated sperm indicated that epididymal sperm acrosomes were apparently in the same stabilized condition as ejaculated sperm. The effect of the pretreatment by high-ionic strength media could be partially mimicked by pretreatment of sperm with alpha- or beta-amylase or neuraminidase but not by beta-glucuronidase, lipase, pronase, or trypsin. Comparison of the ability of bovine follicular fluid, rabbit follicular fluid, and rabbit serum to induce the rabbit acrosome reaction showed that bovine follicular fluid was 3 to 4 times more effective than rabbit follicular fluid and that rabbit serum was totally ineffective in producing the acrosome reaction. The data support a physiologic role for follicular fluids in the process of fertilization and indicate that removal of sperm-bound seminal plasma components is a prerequisite to efficient induction of the acrosome reaction.
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PMID:Removal of sperm-bound seminal plasma components as a prerequisite to induction of the rabbit acrosome reaction. 124 42

The determinant of a mouse sperm maturation antigen was examined morphologically and biochemically with monoclonal antibody T21 as a probe. The plasma membrane components of cauda epididymal spermatozoa were extracted with nonionic detergent Nonidet P-40 and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions and by immunoblotting. Wheat germ agglutinin-lectin staining and immunoblotting indicated that the antigen recognized by T21 is a sialoglycoprotein of about 54,000 daltons (54 kDa). The antigenic determinant was more distinctly exposed after treatment with neuraminidase, as evaluated by immunohistochemistry, immunocytochemistry, and immunoblotting. The cryptic nature of the determinant was further confirmed by immunostaining nitrocellulose strips, subsequently digesting the strips with neuraminidase, and then reimmunostaining them. Results obtained by periodate oxidation treatment suggested that the epitope is a carbohydrate. Immunoperoxidase electron microscopy confirmed that the antigen is distributed on the flagellar plasma membrane of the sperm. This was demonstrated clearly when sperm were desialylated with neuraminidase. These results indicate that the 54 kDa sialoglycoprotein sperm maturation antigen has a cryptodeterminant which can be masked by a sialic acid residue, that is recognized by monoclonal antibody T21.
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PMID:Cryptodeterminant of a sperm maturation antigen on the mouse flagellar surface. 169 31

Molecular forms of esterases were resolved in non-denaturing conditions by using two-dimensional gel electrophoresis with isoelectric focusing in the first dimension and a time-dependent polyacrylamide gradient gel electrophoresis (PAGGE) in the second dimension. This procedure was used to analyse sequential changes in esterase composition along the excurrent genital duct of the mouse and to initiate a specific identification of the androgen-regulated molecular forms. Almost all the 68 variants (pH 3.9-6.4 and 50-300 kDa) revealed by alpha-naphtyl acetate from the fluids of the three parts of the epididymis (caput, corpus, cauda) and vas deferens, could be assigned to the carboxylesterase group as shown by their action on various substrates and sensitivity to inhibitors. Some of these variants co-migrated with those in the serum and testis, whereas other enzyme forms made their first appearance in the caput (13), in the corpus (26) and in the vas deferens (3). The major changes occurred between the caput and the corpus of the epididymis. Only a few acidic spots were not revealed after neuraminidase digestion. Castration of mice (4 weeks) resulted in inhibition of the activity of 34 esterase forms, and thus abolished most of the regional differences in the excurrent duct system. By re-initiating or repressing the synthesis of regional esterase variants, testosterone supplementation (2 and/or 4 weeks) of castrated animals restored the normal esterase pattern in the three epididymal parts, but not in the vas deferens. The major effect of efferent duct ligation (4 weeks) was the emergence in the corpus and cauda of the epididymis of two variants found in the caput of uncastrated mice.
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PMID:Selective action of androgens on the molecular forms of esterases characterized by two-dimensional gel electrophoresis in the epididymis and vas deferens of the mouse. 206 65

Sperm antigen expression during epididymal transit was examined in 4- to 16-week-old intact and castrated ICR mice, using the avidin-biotin complex (ABC) immunohistochemical method with monoclonal antibody T21 against a flagellar surface antigen. On untreated sections, the antigen was first expressed weakly on sperm in the proximal part of the corpus epididymis, and intraluminal components were stained in 4-week-old mice. Epididymal epithelial cells and their stereocilia, and cells in other reproductive organs were not stained. In contrast, on sections treated with neuraminidase, (1) the initial site of antigen appearance is a more proximal position in treated than in untreated sections, (2) stereocilia stained strongly, (3) the staining intensity of sperm and intraluminal components increased, and (4) some clear cells in the epithelium from the distal position of the caput to the corpus epididymis were stained. These results indicate that the antigen is produced by clear cells of the epididymal epithelium, that the antigenic determinant is masked initially by sialic acid residues, and that expression of the antigenic determinant on the sperm surface during epididymal maturation apparently involves desialylation.
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PMID:Masking of sperm maturation antigen by sialic acid in the epididymis of the mouse. An immunohistochemical study. 321 91

The microheterogeneity of androgen-binding protein (ABP) from rat serum and epididymis was examined by subjecting purified native or deglycosylated preparations to analysis by one- or two-dimensional polyacrylamide gel electrophoresis (PAGE) followed by electrophoretic transfer to nitrocellulose and immunochemical localization. Analysis of native ABP by one-dimensional sodium dodecyl sulfate-PAGE confirmed earlier observations that it is composed of subunits and that the subunits of serum ABP had higher apparent molecular weights than those of epididymal ABP. Treatment with neuraminidase, N-glycanase, or O-glycanase, alone or in combination, resulted in decreases in the apparent molecular weight of the subunits. These analyses indicated that terminal sialic acid residues and Asn-linked oligosaccharides were present on both subunits of ABP from the two sources. The fact that the greatest reduction in the Mr of the heavy subunit occurred following treatment with all three enzymes provides evidence that O-linked sugars are present on it. While enzyme treatment did not result in the appearance of a single subunit, chemical deglycosylation did (Mr 39,600). The carbohydrate composition of the heavy and light subunits of intact serum and epididymal ABP was 22 and 9% and 19 and 8%, respectively. Analysis by two-dimensional PAGE indicated that both subunits of the ABPs were composed of isoelectric variants. Although ABP from the two sources had several variants in common, differences were also observed. Treatment of the ABPs with the enzymes resulted in a shift of the pI values to a more basic pH range, indicating that carbohydrate removal also removed charged moieties. The most dramatic shift in the pI values of the isoforms occurred when O-glycanase was present in the enzyme mixture, providing further evidence for the presence of O-linked oligosaccharides on ABP. Isoelectric variants were present even after chemical deglycosylation of ABP.
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PMID:The microheterogeneity of androgen-binding protein in rat serum and epididymis is due to differences in glycosylation of their subunits. 333 17

The treatment of epididymal spermatozoa of guinea pig and ejaculated spermatozoa of rabbit with neuraminidase from Arthrobacter ureafaciens induced significant acrosome reaction while the neuraminidase from Cl. perfringens failed to do so. The addition of the neuraminidase inhibitors kept the enzyme induced acrosome reaction to the control level. The zona-free hamster ova test showed that the treatment of spermatozoa with Arthrobacter neuraminidase rendered 82% of the guinea pig and 69% of the rabbit spermatozoa capable of fertilization. Thus, neuraminidase seems to enhance the rate of acrosome reaction by first capacitating spermatozoa in vitro.
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PMID:Neuraminidase induces capacitation and acrosome reaction in mammalian spermatozoa. 335 41

Ram sperm, isolated from the caput, corpus, and cauda epididymidis, plus ejaculated cells were washed free of loosely bound components and tested for their ability to bind fluorescein-conjugated lectins (Con A, SBA, RCA, PNA, ECA and WGA) as assessed by epiluminescent-fluorescence light microscopy and flow cytometry. Detailed preliminary studies established an appropriate lectin-to-sperm ratio and incubation conditions for quantitative comparisons of sperm cell types and permitted a detailed analysis of both the amount of lectin bound as well as its distribution on the various aspects of the cell surface. Con A (mannose positive) bound weakly over the entire surface, with little change associated with maturation in the male tract. SBA (N-acetylgalactosamine positive) bound moderately strongly to caput sperm, with an emphasis on the apical ridge portion of the cell; during epididymal transit this binding was greatly diminished and was regained upon ejaculation. RCA, PNA, and ECA (galactose positive) gave generally equivalent results, where initially strong binding to the entire sperm surface decreased (over all parts of the surface except the anterior head) during epididymal maturation, with no change associated with ejaculation. WGA (sialic acid positive) binding initially was weak, but increased with epididymal transit and ejaculation. In vitro incubations with beta-galactosidase and neuraminidase confirmed the assignments given above. These data, when coupled with previous reports describing the heterogeneous distribution of proteins and lipids and changes in their distribution associated with epididymal maturation, serve to quantitatively describe changes in those aspects of the cell surface that are probably responsible for the acquisition of the capacity of the sperm to bind successfully to the oocyte.
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PMID:Changes in lectin-binding features of ram sperm surfaces associated with epididymal maturation and ejaculation. 337 79

The structure, relative density, and distribution of anionic sites on the surface of epididymal and ejaculated spermatozoa were studied using polycationic ferritin (CF), colloidal iron hydroxide (CIH), various enzymatic treatments, methylation, and de-acetylation. Macro-molecules containing sugar residues, probably sialic acid, are part of the sperm membrane and show a characteristic distribution and density that is dependent of the sperm region and of its origin. Unlike the spermatozoa of other eutheria examined, the exposure of the stallion spermatozoa to neuraminidase treatment did not produce significant changes in the density of the negative charge of the sperm surface. The ability of purified neuraminidase to act only after saponification suggests that sialic acid may be present in the acetylated form. When CIH was used it is seen that the density of the negative charge is rather uniform within a particular segment of the spermatozoa and abruptly changes at the junction of morphologically distinct segments (Between the acrosomal and post acrosomal region of the sperm head and between the post acrosomal region and middle piece of the flagellum). The acrosome presented more negative groups dissociated at pH 1.8 than the postacrosomal region. A greater concentration of anionic sites over the flagellum was also observed when CIH and CF were used. This asymmetry probably represents different domains that may be related to specific functions. The cytochemical observations and the cellular electrophoretic mobility measurements did not show striking differences on the negative charge of sperm obtained from different regions of epididymis and ejaculates in contrast to previous results in other species. The spermatozoa collected from caput epididymidis bind CIH but not all population present equal response. In corpus and cauda region of epididymis the population displaying the capacity to bind CIH or CF significantly over the head and tail surface was the majority. This study corroborates that the distribution and density of terminal oligosaccharide residues on the sperm plasma membrane has species specific characteristics. The surface charge of the spermatozoa obtained either during the breeding or nonbreeding season, determined by measurements of cellular electrophoretic mobility and by the binding pattern of CIH and CF, does not show significant differences.
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PMID:Cytochemical analysis of the anionic sites on the membrane of the stallion spermatozoa during the epididymal transit. 350 80

When androgen-binding protein (ABP) in unfractionated immature (20-day old) male rat serum was covalently labeled with the site-specific photoaffinity ligand [3H]17 beta-hydroxy-4,6-androstadien-3-one and analyzed on 5.6% polyacrylamide tube gels containing SDS (SDS-PAGE), a protein of Mr 33,700 +/- 1200 was shown to be specifically labeled. Rat epididymal ABP from unfractionated cytosol analyzed under identical conditions exhibited two androgen-specific peaks of radioactivity, Mr 49,900 +/- 600 and Mr 44,100 +/- 800, which correspond to the previously described subunits of ABP. The apparent molecular weight differences between serum and epididymal ABP were further assessed on preparations of serum ABP that had been partially purified by chromatography on Affi-Gel blue (to remove albumin) and on Sephadex G-150 (to remove other proteins). When these preparations of ABP were photolabeled and analyzed by SDS-PAGE as above, two subunits of Mr 61,700 +/- 1300 and Mr 47,100 +/- 700 were resolved. Serum and epididymal ABP were further purified by androgen affinity chromatography. When these preparations were subjected to SDS-PAGE on slab gels containing 10% polyacrylamide and identified by fluorography of photolabeled ABP or by immunochemical localization following electrophoretic transfer to nitrocellulose, differences in the apparent molecular weight of ABP from the two sources persisted. Immunochemical localization studies on ABPs that had been desialylated with neuraminidase indicated that there was an increased mobility of the subunits, as one would anticipate from removal of carbohydrate. Differences in apparent molecular weight of ABPs from the two sources are likely due to differences in glycosylation.
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PMID:The apparent molecular weight of androgen-binding protein (ABP) in the blood of immature rats differs from that of ABP in the epididymis. 366 61

To determine sequential surface glycoprotein changes in ram spermatozoa during epididymal maturation, labeling procedures were used that were specific for galactosyl, galactosaminyl, and sialyl residues. Spermatozoa and fluids were collected from the rete testis through surgically inserted catheters or flushed from the lumen of selected regions of the epididymis: i.e., caput, proximal and distal corpus, and cauda epididymidis. Ejaculated spermatozoa were collected by electrical stimulation. Electrophorectic analysis of galactose (GAO)-sodium boro[3H]hydride (NaB3H4)-treated spermatozoa revealed a sharp overall decrease in carbohydrate residue labeling during sperm transport through the efferent ducts and caput epididymidis, whereas several high molecular weight components in the 600K to 250K zone persisted throughout epididymal transit. Preincubation of spermatozoa with neuraminidase (NEUA) exposed galactose residues that had not been labeled with GAO alone (i.e., 97K, 43K, 24K) in both cauda epididymal and ejaculated spermatozoa. Treatment with sodium metaperiodate-NaB3H4 labeled many of the surface components displayed by NEUA-GAO-treated spermatozoa and revealed an overall shift in sialyl residue labeling from high molecular weight components in immature testicular spermatozoa to low molecular weight components in mature cells. The labeling procedures applied allowed only a qualitative interpretation of the results and they presumably represent the minimum possible changes. Nonetheless, our results demonstrate that glycoproteins are a major factor in surface transformations of ram spermatozoa in the epididymis, especially during the initial stages of maturation.
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PMID:Glycoproteins: a variable factor in surface transformation of ram spermatozoa during epididymal transit. 406 38


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