Different phases of oocyte maturation: Oocyte maturation is a complex long-cell procedure containing meiotic cycle development (from
diplotene to Metaphase-II) and reprogramming of cytoplasmic events, enabling oocytes to achieve their fertilization and embryogenesis (Eichenlaub et al.,2013).
Meiosis in oocyte nuclei ceases at the
diplotene stage of prophase I, during which they connect to one another by cytoplasmic bridges.
Role of Greatwall kinase in release of mouse oocytes from
diplotene arrest.
During
diplotene, diakinesis and metaphase I, 16 autosomal bivalents and three univalent sex chromosomes were seen; generally, one chiasma (i.e., interstitial or terminal type) per bivalent was observed (Fig.
All five species analyzed here present a SCS of the X0/XX type, which was confirmed due to the difference of one chromosome between male and female mitotic metaphase cells (except in Mesabolivar togatus, in which females were not analyzed), presence of only one chromosomal univalent in male
diplotene, and occurrence of the X chromosome in only one pole in metaphase II cells.
The presence of primary spermatocytes at two different stages, specifically zygotene and
diplotene, with large nuclei observed in spermatocytes in the
diplotene stage, was the other notable characteristic of this stage.
Reduced AR has an influence on the functions of Sertoli cells in supporting and nurturing germ cells, causing the arrest of spermatogenesis at the
diplotene spermatocyte stage of meiosis [13, 31].
During the
diplotene stage of prophase, when the chromosomes separate, the mitochondria and most other organelles localise to one side of the nucleus forming Balbiani's vitelline body [191, 192].
Primary spermatocytes, stained with the anti-SCP3 antibody, were selected to evaluate the respective percentages of leptotene, zygotene, pachytene and
diplotene stages.
The preleptotene spermatocytes enter prophase I of meiosis, transform into leptotene, zygotene, pachytene and
diplotene cells, which then quickly finish meiosis I forming secondary spermatocytes.