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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The epithelium of the monkey epididymis was studied by means of freeze-fracture techniques and conventional electron microscopy. For the study of transepithelial permeability lanthanum hydroxide was used as an intercellular tracer. The epididymal epithelium consists mainly of tall columnar cells. The long stereocilia at the apical surface, similarly to microvilli, exhibit after freeze-fracture, two distinct faces: the E face, concave and with fewer membrane-associated particles, and the complementary convex P face. In the lumen unusual groups of smooth-surfaced vacuoles are present. A tight junctional network, which shows some permeability to the lanthanum tracer, is located at the apical end of the cells. Supranuclear cross-fractures clearly show the well developed Golgi cisternae and numerous vacuole profiles. The highly infolded, centrally located nucleus exhibits, after freeze-fracture, an even distribution of nuclear pores. In the perinuclear region the rough endoplasmic reticulum, which also presents pores, displays a sheet-like organization. The basal cytoplasm is filled by numerous globular profiles of membrane-bounded granules. Freeze-cleave exposes large cytoplasmic areas where the types and amount of organelles indicate an intense metabolic activity.
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PMID:Fine structure of the monkey epididymis: a correlated thin-section and freeze-cleave study. 11 68

This paper explores the relationship between the galactose oxidase-sensitive glycoproteins from rat caudal epididymal sperm and fluid and, in addition, their relatedness to the 32,000-Da major acidic secretory glycoproteins of caudal epididymal fluid. The major acidic secretory glycoproteins were purified by a combination of high-resolution anion-exchange (Mono Q) and gel permeation (Bio-Sil TSK 125) chromatographic steps. Immunoprecipitation studies, peptide mapping, and the inability to label the purified glycoprotein by galactose oxidase/sodium boro[3H]hydride clearly established that the galactose oxidase-sensitive fluid and membrane glycoproteins were not related to these acidic secretory glycoproteins. Membrane and fluid tritium-labeled glycoproteins were shown to be closely related, but not identical, polypeptides. Sugar analysis indicated that both glycoproteins contain N- and O-linked saccharide chains and that the galactose oxidase-sensitive residue was present only on O-linked sugars. It was also found that efficient labeling of the 32,000-Da fluid glycoprotein was possible only if protease inhibitors were omitted from all buffers used in the isolation of caudal epididymal fluid and subsequent labeling procedures. This suggests that the fluid glycoprotein was acquired by the unintentional proteolysis of the membrane glycoprotein. Polyclonal antibodies raised against caput sperm plasma membranes immunoprecipitated tritium-labeled glycoproteins from both caudal epididymal fluid and sperm membrane, suggesting that a precursor form of the caudal galactose oxidase-sensitive glycoprotein may be present on caput sperm.
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PMID:Characterization of the maturation-associated galactose oxidase-sensitive glycoproteins of rat caudal sperm plasma membrane and epididymal fluid. 293 Jan 87

Freeze-fracture studies were used to investigate the size, density, and distribution of intramembranous particles (IMPs) in the plasma membrane of the sperm head of two species of Australian hydromyine rodents Pseudomys australis and P. nanus both of which are characterized by having, in addition to a dorsal hook, two long ventral hooks that extend from the antero-concave surface. It was found that on the P face of the plasma membrane over the dorsal hook of caput and upper corpus spermatozoa a paracrystalline arrangement of small, approximately 7nm, IMPs were interspersed with a few large, 9 to 12 nm, IMPs. In the cauda epididymidis the small particles became randomly arranged. On the P face of the plasma membrane over the ventral hooks of caput sperm, and in the postacrosomal region, a much higher density of large, 9 to 12 nm, IMPs was present. In the ventral hooks of cauda sperm the IMPs were increased even further and were arranged in short, variably orientated, ridges; this did not appear to be evident in the plasma membrane over the postacrosomal region. It suggests a change in distribution of the IMPs in the cell membrane over the ventral hooks, but not over the postacrosomal region, during epididymal transit of the spermatozoa. This may indicate that the plasma membrane of these two regions of the head of ejaculated spermatozoa has intrinsic differences in its structure and function.
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PMID:Variation in intramembranous particle distribution in the cell membrane of the sperm head of the plains rat and western chestnut mouse (Pseudomys Spp.). 339 73

The epithelium of caput and cauda epididymidis of the rat was studied with transmission electron microscopy (TEM) and freeze-fracture techniques. In thin sections of both zones, the tissue consisted mainly of tall columnar cells (principal cells) with long sterocilia. Clusters of small membrane-bound vesicles were located in the lumen between or immediately over the stereocilia. Freeze-fracture replicas also displayed groups of smooth-surface vesicles in the same location. Membrane-bound vesicles isolated from the lumen of the rat epididymis were studied by TEM. In thin sections, some of them contained an electron dense material and others looked empty. In addition, the hydrolases: beta-galactosidase, N-acetyl-glycosaminidase, alpha-mannosidase, aryl-sulfatase and beta-glucuronidase were detectable in pellets of vesicles treated with Triton X-100. The results presented here indicate the presence of membrane-bound vesicles observed by two different methodologies in the rat epididymal fluid and demonstrate five glycosidases in their content.
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PMID:Morphological and enzymatic study of membrane-bound vesicles from the lumen of the rat epididymis. 775 84

The organization of sperm chromatin in the dasyurid marsupial, Sminthopsis crassicaudata, was investigated using various morphological techniques. Transmission electron microscopy indicates two quite distinct chromatin regions became evident late in spermiogenesis with an outer globular region containing blocks of very electron-dense chromatin. Fluorescent light microscopical studies after staining with DNA dyes and 7-amino actinomycin D of testicular, caput, and cauda epididymal spermatozoa showed that this region fluoresced less brightly than the rest of the nucleus, indicating the presence of fewer DNA binding sites. Freeze fracture showed that the chromatin in most of the nucleus had randomly arranged particles of various sizes, but that of the outer region was composed entirely of small particles. This outer region was more resistant to low concentrations of the ionic detergent, SDS, whereas both guanidine hydrochloride and urea together with sodium chloride generally dispersed all the chromatin except that in the outer globular region and in a localized area of the nucleus beneath the acrosome. This study has thus revealed that the outer globular chromatin of these spermatozoa responds differently to ionic detergents and protein denaturing agents and has a different chromatin organization than most of the rest of the nucleus. The significance of these differences remains, however, to be determined.
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PMID:Unusual nuclear structure of the spermatozoon in a marsupial, Sminthopsis crassicaudata. 812 34

The changes in distribution of protein and sugar components in, and on, the plasmalemma of the spermatozoon during epididymal transit of a marsupial, the brush-tail possum, Trichosurus vulpecula, are described. Freeze-fracture studies indicate a change in organization of plasmalemma intramembranous particles of both the head and midpiece of the tail as the spermatozoa pass from the caput to cauda epididymides. Staining with fluorescein isothiocyanate (FITC)-lectins shows, that heads of caput spermatozoa stain with Con A, WGA, RCA120, LCA and JAC, whereas those from the cauda epididymides stain only with LCA and JAC, thus suggesting that N-acetyl-beta-D-glucosamine, alpha-D-glucose, or beta-D-galactose may either become lost or masked during epididymal transit. A reduction of alpha-D-mannose is also suggested. Collectively these results show that the plasmalemma of the spermatozoon of at least this marsupial species undergoes both protein and saccharide modification during transit of the epididymis. How these findings relate to sperm maturation in preparation for sperm-egg binding has yet to be determined.
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PMID:Extratesticular sperm maturation in the brush-tail possum, Trichosurus vulpecula. 1064 81

We report use of an in vitro assay (Barbato et al., 1998: Biol Reprod 58:686-699) to assess binding ability of cauda epididymal mouse sperm to a surrogate zona pellucida and effect of a synthetic peptide (Amann et al., 1999: J Androl 20: 42-46) on fertilization ability in in vitro fertilization (IVF) tests. Sperm from C57Bl/6, CD1, and CF1 mice (4 replicates each) were evaluated for binding ability after exposure to 0 (control) and 80-1280 pM peptide. For control sperm, endogenous binding was C57Bl/6 < CD1 = CF1 (P < 0.05, 1-way ANOVA). Across all three strains, exposure to > 320 pM peptide increased relative binding of sperm (P < 0.05; 2-way general linear model; GLM). Strains differed both in basal binding ability and in response to synthetic peptide. To determine if IVF rate increased after exposure of sperm to peptide, ova from B6C3 mice (four replicate pools) were collected after eCG and hCG stimulation. Cumulus-oocyte complexes (COC; 8-15 ova in each of 3-6 drops/treatment) were incubated with hyperactivated C57Bl/6 sperm at approximately 1500 sperm per ovum. Data for incubations were corrected for false-positive classification to yield a better estimate of true cleavage rate, and then related to results observed with a tenfold greater sperm concentration. Relative cleavage rates were 0 peptide (0.48); 420 pM (0.78, P < 0.05); and 840 pM (0.90, P < 0.01; GLM and Tukey tests). IVF rate was increased by exposure of mouse sperm to peptide at concentrations effective in the in vitro assay, and use of peptide allowed use of 1/10 as many sperm.
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PMID:Increased in vitro binding and fertilizing ability of mouse sperm exposed to a synthetic peptide. 1106 70

Freeze-storage of epididymal sperm is an important technique for the preservation of gametes in animals, including those becoming extinct. We froze canine sperm recovered from the cauda epididymis and investigated the fertility. The qualities of sperm from the cauda epididymis before freezing were: mean sperm motility, 89.4 +/- 1.6 (SE) %; sperm viability, 89.1 +/- 1.1%; and these were significantly higher than those of sperm from the caput-corpus epididymis (P<0.01, P<0.05). The number of sperm recovered from both cauda epididymides varied among animals: 6.3-122.3 x 10(7), mean 61.5 +/- 10.0 x 10(7). Freezing was used only for sperm recovered from the cauda epididymis. The sperm motility and viability after thawing were 19.5 +/- 2.5% and 53.1 +/- 3.3%, respectively. These were slightly lower than those of frozen-thawed ejaculated sperm, but the differences were not significant. When 2 x 10(8), 3 x 10(8), or 4 x 10 (8) sperm were inseminated in the unilateral uterus, only one animal inseminated with 3 x 10(8) sperm was fertilized (1/16, 6.3%). When 1 x 10(8) sperm were inseminated in the bilateral uterine tubes, one of six animals (16.7%) was fertilized. Therefore, although the qualities of epididymal sperm after thawing were similar to those of ejaculated sperm, the conception rate obtained with frozen-thawed epididymal sperm was low in beagle dogs. It is necessary to investigate the differences in damage between epididymal sperm after thawing and ejaculated sperm and to develop a method for improving the conception rate.
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PMID:Artificial insemination of frozen epididymal sperm in beagle dogs. 1496 Aug 8

Freeze-fracture replicas of stallion spermatozoa, collected from the proximal caput, corpus and cauda epididymides regions, were analyzed by electron microscopy to explore the distribution and density of intramembrane particles (IMP). Conspicuous differences in density and arrangement of the IMP were observed in the different topographical domains of mature and immature spermatozoa. A reduction of IMP, especially remarkable in the post-acrosomal domain, was observed in mature epididymal spermatozoa when compared with samples collected from ductuli efferentes. Some structural species-specific differences were also observed. The significance of these changes has not been determined, but remodeling of membrane components during developmental processes constitutes a fine control mechanism to ensure that key molecules are in the correct membrane position and during an appropriate timeframe to mediate fertilization.
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PMID:Post-testicular changes in the density and distribution of intramembrane particles of stallion sperm surface domains. 1701 74

Macropod spermatozoa have proven difficult to cryopreserve such that empirical studies using high concentrations of glycerol and/or DSMO have resulted in only 10% post-thaw motility. We examined the ultrastructure and freeze-fracture of caput and cauda epididymal macropod spermatozoa at 35, 4 degrees C and following cryopreservation with and without 20% glycerol. The addition of 20% glycerol resulted in significant damage to the sperm plasma membrane and mitochondria compared to no glycerol at the same temperatures (P<0.05). Following cryopreservation, 20% glycerol significantly improved the preservation of the cauda epididymal sperm plasma membrane and mitochondria and reduced the incidence of axonemal damage and axonemal spaces. For caput epididymal spermatozoa, glycerol only improved the preservation of the plasma membrane following cryopreservation (P<0.05). Freeze fracture microscopy revealed a pattern of helically wound intramembranous particles in the plasma membrane over the fibre network of the mid piece of the sperm tail. The fibre network is an interconnecting cytoskeletal structure found underneath the plasma membrane of the kangaroo sperm midpiece and is thought to add rigidity to the proximal portion of the sperm tail. After thawing, the plasma membrane was damaged such that this structure was missing in patches, and the helical rows of particles were mal-aligned. On the principal piece, particles were arranged randomly at physiological temperatures; however, upon cooling to 4 degrees C with 20% glycerol, the particles become aggregated. Once rewarmed (35 degrees C), particles over the principal piece resumed their random organisation. This finding is further evidence of a reversible phase transition of the macropod sperm plasma membrane during cooling that is not associated with a loss of motility or membrane integrity.
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PMID:Ultrastructural observations of cryoinjury in kangaroo spermatozoa. 1746 21


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