(1) For a brief interval, the two pronuclei sit side by side in the cytoplasm.

(2) The two pronuclei remain roughly in step, but each takes its own time.

(3) The male pronucleus forms when the second meiosis is completed.

(4) But the rate of pronucleus formation and developmental ability of these matured oocytes when fertilized in vitro, were low.

(5) It then swells-for the nuclear material is highly compacted within the sperm-and so becomes a pronucleus.

(6) Short time delay don't result in preimplantation embryos death, but impacted blastula rate of pronucleus embryos.

(7) Objective To investigate the relationship between the first polar body morphology of oocyte and the zygote morphology in pronucleus stage, embryo quality in cleavage stage.

(8) The ooplasm of gynogenetic crucian carp may also lack some high molecules responsible for membrane assembly of male pronucleus.

(9) After fertilization, GSH plays an active role in the formation of the male pronucleus, and has a beneficial effect on early embryogenesis.

(10) After the sperm penetrated into the egg, its nucleus was transformed into a big male pronucleus.