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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1120110404
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