Pronucleus formation in bovine oocytes activated by a single electric pulse.
Bovine oocytes matured in vitro were stimulated by a single pulse of direct current (DC), then cultured for 0.5-6 h and evaluated by light (LM) and transmission electron microscopy (TEM). At the light microscopic level, the beginning of oocyte chromatin decondensation was first observed 3 h post-activation (14%). A well-developed pronucleus with evenly granulated nucleoplasm surrounded by nuclear membrane was found in 12, 61 and 81% oocytes at 4, 5 and 6 h post-activation, respectively. The TEM evaluation revealed that nuclear membrane vesicules were first visible at 0.5 h post-activation and became even more prominent at 1 h. Based on these observations, it is concluded that a nuclear membrane starts to form immediately after oocyte activation, while a well-developed pronucleus appears at 4-6 h.
Bĕhalová
E
E
Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Libĕchov.
Smith
S D
SD
Hyttel
P
P
Greve
T
T
D000818:Animals; D002417:Cattle; D002467:Cell Nucleus / Q000648:ultrastructure*; D002843:Chromatin / Q000648:ultrastructure; D004558:Electric Stimulation; D005260:Female; D008540:Meiosis; D008854:Microscopy, Electron; D009685:Nuclear Envelope / Q000648:ultrastructure; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure; D010312:Parthenogenesis; D013997:Time Factors
D002843:Chromatin