Parthenogenetic Activation of Porcine Oocytes After Nuclear Transfer

Abstract

Mature porcine oocytes are arrested at metaphase II of meiosis. At fertilization, like all mammalian oocytes they exhibit a low frequency Ca(2+) oscillation lasting several hours. This oscillation is thought to be the signal that triggers resumption of meiosis and activates the developmental program of the oocyte. The signal transduction mechanism of the sperm-induced Ca(2+) signal is not known in detail, and attempts to generate the oscillation artificially have met with little success. Nevertheless, artificial activation of the oocyte is a crucial step during nuclear transfer. Methods are available to induce a transient elevation in the intracellular free Ca(2+) concentration to surpass the meiotic arrest and induce development of the constructed embryo. Further studies concentrating on the mechanism of Ca(2+) signaling during fertilization will help to improve the efficiency of the procedures used for parthenogenetic activation of the oocyte.

Intracytoplasmic Sperm Injection in Livestock Species: An Update

“…1993). On the other hand, parthenogenetic activation can be induced through the elevation of cytoplasmic free calcium by several methods (see review by Machaty et al. 1999).…”

“…The primary role of the fertilization calcium signal is to downregulate the activity of the cell cycle regulatory MPF that leads to exit from the metaphase arrest (Lorca et al 1993). On the other hand, parthenogenetic activation can be induced through the elevation of cytoplasmic free calcium by several methods (see review by Machaty et al 1999). Even, spontaneous activation by in vitro oocyte ageing can be performed (Kikuchi et al 1995).…”

Parthenogenetic Activation of Porcine Oocytes by Electric Pulse and/or Butyrolactone I Treatment

“…Activation methods in the pig have been reviewed recently by Machaty, et al (1999). Most activating treatments affect a broad spectrum of cellular components; in addition to the activating effect, physiology of the oocyte may be altered in various ways.…”

Controlled Stress Improves Oocyte Performance – Cell Preconditioning in Assisted Reproduction

“…The HHP treatment did not cause parthenogenetic activation in the studies when TCMH medium was used to hold oocytes during treatment. As various physical (mechanical, electronic, osmotic), chemical and other treatments (Machaty and Prather 1998; Machaty et al. 1999; Somfai et al.…”

“…The HHP treatment did not cause parthenogenetic activation in the studies when TCMH medium was used to hold oocytes during treatment. As various physical (mechanical, electronic, osmotic), chemical and other treatments (Machaty and Prather 1998;Machaty et al 1999;Somfai et al 2007;Tian et al 2007) were reported to cause parthenogenetic activation, further experiments were conducted to investigate the effect of various holding media with different Ca 2+ concentrations on possible-HHP induced parthenogenetic activation of the oocytes. The media included TCMH medium, mannitol-PVA fusion medium with (MPVA+Ca 2+ ) or without Ca 2+ and Mg 2+ (MPVA).…”