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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 11 (1985), S. 367-377 
    ISSN: 0148-7280
    Keywords: bovine sperm ; cryopreservation ; plasma membrane ; protein loss ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Cryopreservation of bovine sperm in egg-yolk citrate extender (EYC) usually maintains fertility. Since plasma membrane proteins are important for the fertilizing potential of sperm, the possible loss of membrane proteins from sperm subjected to cryopreservation in EYC was evaluated. Sperm were washed and labeled with 125I without significantly reducing motility. Radiolabeled sperm were a) held for 2 hr at 22°C in N-2-hydroxyethylpiperazine-N'-ethanesulfonic acid (HEPES)-buffered saline containing 1% polyvinyl alcohol, b) cooled to 5 °C in glycerol-free EYC and held for 3 hr, or c) frozen-thawed in EYC containing 7% glycerol. Sperm were solubilized and proteins were separated by electrophoresis under denaturing conditions. Freeze-thawing dislodged most egg-yolk proteins from the spermatozoal plasma membrane that were bound to and retained by sperm that only were cooled to 5 °C. Autoradiography resolved 11-18 bands of 125I polypeptides. There was no difference (P 〉 0.05) in the amount of 125I protein retained by frozenthawed and cooled sperm. However, the radioactivity in two polypeptide bands (MW = 105 K and 24.2 K) was less (P 〈 0.05) for sperm held at 22 °C in HEPES-buffered saline. Thus, holding sperm in buffered saline at 22 °C resulted in a greater loss of 125I proteins from the plasma membrane than did cryopreservation of sperm in EYC. Cryopreservation did not induce greater loss of 125I proteins from the plasma membrane than simply cooling sperm to 5 °C in EYC.
    Additional Material: 2 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 17 (1987), S. 213-219 
    ISSN: 0148-7280
    Keywords: membrane integrity ; cryopreservation ; acrosin ; micro-assay ; sperm isolation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Isolation of a self-selected population of motile spermatozoa is possible by using a gradient of bovine serum albumin (BSA). We determined if exposure to BSA altered the sperm or if isolated sperm differed from nonisolated cells in terms of motility or activity of sperm-bound amidase, either before or after subsequent cryopreservation. Exposure of sperm to 6% BSA in egg yolk Tris extender induced changes in the plasma and acrosomal membranes of sperm that resulted in exposure and activation of sperm-bound amidase (P 〈 .01). In experiment 2, semen extended in egg yolk Tris was cooled to 5°C or layered onto a solution of 6% BSA in extender at 37°C, from which the sperm that had swum into the BSA solution were recovered 2 h later and cooled to 5°C. Sperm in both treatments were cryopreserved. The percentage of progressively motile sperm was determined visually and by track motility. Activity of sperm-bound amidase exposed to substrate was evaluated. After recovery of sperm from the 6% BSA solution, 81% were progressively motile as compared to 59% in the starting samples (P 〈 .01). However, the amount of exposed sperm-bound amidase also was greater (P 〈 .05) this was a deleterious change. Immediately after thawing, more (P 〈 .01) sperm were motile in samples of isolated sperm than for nonisolated cells (43 vs 24%), but after incubating the thawed sperm for 1 h at 37°C there was no difference. After freezing and thawing of sperm, amidase activity was higher (P 〈 .05) for the isolated sperm than for nonisolated cells. Thus, isolation of sperm using a 6% BSA gradient increased the proportion of progressively motile sperm, but decreased the percentage of sperm with an intact acrosome, based on measurements of amidase activity.
    Additional Material: 1 Ill.
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