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Phase transition temperature and chilling sensitivity of bovine oocytes.

Author(s) : ARAV A., ZERON Y., LESLIE S. B., BEHBOODI E., ANDERSON G. B., CROWE J. H.

Type of article: Article

Summary

In the present study, the authors examined the phase transition of the membrane lipids of immature and in vitro-matured bovine oocytes during cooling, using Fourier transform infrared spectroscopy. The phase transition of the membrane lipids of oocytes at the germinal vesicle (GV) stage occured between 13 and 20 deg C, while a very broad phase transition, which centered around 10 deg C, was observed for mature oocytes (MII) stage. Thermotropic phase transitions were demonstrated to be related to the temperature at which direct chilling injury affected the integrity of the oocyte membranes. The high rate of polyspermy indicates that a site(s) other than the plasma membrane is affected during cooling of bovine oocytes. Nucleate bovine GV oocytes were electrofused with in vitro-matured and enucleated oocytes, and then cooled to 4 deg C. Evaluation of the membrane integrity of the fused oocytes showed that these oocytes are chilling resistant, which strongly suggests that alteration of the membrane composition of an oocyte can change the cell's susceptibility to low temperatures. This finding led to an improvement in the survival of oocytes after cryopreservation.

Details

  • Original title: Phase transition temperature and chilling sensitivity of bovine oocytes.
  • Record ID : 1998-0602
  • Languages: English
  • Source: Cryobiology - vol. 33 - n. 6
  • Publication date: 1996/12

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