Parthenogenetic activation of cattle oocytes by a single pulse of direct current

Bovine follicular oocytes cultured in vitro for 26-27 h were exposed to AC/DC cycle. Mature and immature oocytes were effectively parthenogenetically activated by a single DC-pulse of a different voltage. Application of AC/DC cycle with 60 V DC-pulse (30 microseconds) resulted in 96% of activated mature and 94% of activated immature oocytes. The high activation rate was also recorded when oocytes were treated with higher voltage. The exposure of oocytes to 120 V and 240 V pulses increased the number of degenerated oocytes (6% to 46%) and incidence of oocytes with two pronuclei. The resumption of meioses was observed in 92% of mature and 88% of immature oocytes 1 h after DC-pulse and pronuclei formation was recorded in 72% of mature and 40% of immature oocytes after 6 h of IVC. Two-cell stage parthenogenones were obtained after prolonged IVC (22%) or after transfer into mouse oviducts for 44 h (61%). Possible use of parthenogenetic pronuclear oocytes and 2-cell parthenogenones in pronuclear/nuclear microinjection and nuclear transplantation experiments is outlined.