Cytoskeletal alteration in aged porcine oocytes and parthenogenesis

Microtubule and microfilament organization in immature, in vitro matured and in vitro fertilized prepubertal goat oocytes

“…Also, disorganized tubulin (not organized as an aster) was observed around condensed sperm heads in 1PN, asynchronous 2PN and polyspermic oocytes. These results are similar to those obtained by Kim et al (1996b) in polyspermic pig oocytes, where multiple spermatic asters were observed in polyspermic oocytes associated with penetrating spermatozoa.…”

DNA synthesis, microtubule and nuclear dynamics in porcine parthenotes

“…Inadequate cytoplasmic maturation of oocytes or activation stimulus impairs the normal function of cytoplasmic organelles and thus results in the lower developmental ability of oocytes used for cloning or parthenogenesis. In a further study, the thick microfilament domain of the cortex was supposed to be important for polar body extrusion and microfilaments around each pronucleus thereafter played an independent role in the cleavage process (Kim et al, 1996b). However, in the present study, microtubules were always observed to be involved directly with second polar body extrusion and the later process of cleavage.…”

Inhibitory effects of calcium ionophore pretreatment of porcine oocytes on polyspermic fertilization

“…These results suggest that a long period is required to establish polyspermic inhibition when oocytes are treated with a moderate concentration of calcium ionophore. It is known that the ageing of oocytes influences their developmental competence (Kim et al, 1996a). In the present study, the treatment of oocytes with calcium ionophore prevented polyspermic fertilization regardless of the maturation period (40 or 44 h).…”