||Thermostability of Sperm Nuclei Assessed by Microinjection into Hamster Oocytes.
Yanagida, K. ;
Perreault, S. D. ;
Kleinfeld, R. G. ;
Yanagimachi, R. ;
||Environmental Protection Agency, Research Triangle Park, NC. Reproductive Toxicology Branch. ;John A. Burns School of Medicine, Honolulu, HI. Dept. of Anatomy and Reproductive Biology.
Cell nucleus ;
Golden hamsters ;
Species specificity ;
Cross-linking reagents ;
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||Nuclei isolated from spermatozoa of various species (golden hamster, mouse, human, rooster, and the fissh tilapia) were heated at 50 - 125 deg for 20-120 min and then microinjected into hamster oocytes to determine whether they could decondense and develop into pronuclei. Mature, mammalian sperm nuclei, which are stabilized by protamine disulfide bonds, were moderately heat resistance. For example, they remained capable of pronucleus formation even after pretreatment for 30 min at 90 C. Indeed, a temperature of 125 C (steam) was required to inactivate hamster sperm nuclei completely. On the other hand, nuclei of rooster and tilapia spermatozoa and those of immature hamster and mouse spermatozoa, which are not stabilized by protamine disulfide bonds, were sensitive to heating; although some of them decondensed after exposure to 90 C, none formed male pronuclei. Furthermore, nuclei of mature hamster sperm became heat labile when they were pretreated with dithiothreitol to reduce their protamine disulfide bonds. These observations suggest that the thermostability shown by the nuclei of mature spermatozoa of eutherian mammals is related to disulfide cross-linking of sperm protamines.
||Pub. in Biology of Reproduction, v44 n3 p440-447 Mar 91. Prepared in cooperation with John A. Burns School of Medicine, Honolulu, HI. Dept. of Anatomy and Reproductive Biology.
|NTIS Title Notes
||Reprint: Thermostability of Sperm Nuclei Assessed by Microinjection into Hamster Oocytes.
||PC A02/MF A01