Cryomicroscope investigation and thermodynamic modeling of the freezing of unfertilized hamster ova.
Thermodynamic computer modeling was used to predict the freezing response of single-celled unfertilized hamster ova. The cell membrane transport characteristics were investigated, using a microscope diffusion chamber system. The mean osmotically inactive cell volume was determined to be 21.6% of the initial cell volume. An overall mean value of 0.8 +/- 0.1 micron3/micron2.min.atm (= 18 +/- 2.5 micron/sec) was determined for the membrane hydraulic coefficient, Lp. The effect of the extracellular solute concentration on Lp was determined at room temperature (approximately 23 degrees C). A thermodynamic computer model was used to predict the cell response to freezing. The predicted response was compared to the actual volumetric response observed during freezing on a temperature-controlled cryomicroscope conduction stage. The effect of the cooling rate on the nucleation temperature of unprotected ova and protected ova suspended in a 1.5 M DMSO solution was investigated. Overall mean nucleation temperatures of -13 and -57.1 degrees C were observed for unprotected and protected ova, respectively, where the mean nucleation temperature for protected ova was strongly cooling rate dependent.
Shabana
M
M
Mechanical Engineering Department, Michigan State University, East Lansing 48824.
McGrath
J J
JJ
D000818:Animals; D002463:Cell Membrane Permeability; D003198:Computer Simulation; D006224:Cricetinae; D005260:Female; D005615:Freezing; D008954:Models, Biological; D009995:Osmosis; D010063:Ovum / Q000166:cytology / Q000378:metabolism; D011309:Preservation, Biological; D013816:Thermodynamics; D014867:Water / Q000378:metabolism
D014867:Water