Flow cytometrically-sorted sperm as well as unsorted control sperm from the same bulls were cryopreserved. Hence, the AnT is abruptly truncated and relatively thick compared to the posterior region of the tail which is often obviously bifurcated Figure 3B and invariably tapered too gradually for its distal extremity to be resolved. In summary, the use of non-invasive imaging parameters showed that the start of first cleavage was delayed in the XXO group and that the majority of embryos in the XX0 group had P2 values of less than one hour due to the Type 1 cleavage pattern. Following this, each zygote was cultured separately for re-examination either during first cleavage or at the early 2-cell stage to see if the orientation of axes defined by the PB s appeared to have been conserved. Hence, validation of the use of PHA-treated microspheres as a surface marker depends crucially on demonstrating that they retain their relative position at least through the first cleavage division. There has been no classification reflecting both eggshell formation and embryo development.
There seems to be a close correlation between eggshell formation and formation of area pellucida. One daughter nucleus migrates into adjacent yolk, while the other remains in situ. Central cells in a cleaving embryo seemed to divide very rapidly while peripheral cells, including open cells, divided relatively very slowly. Asymmetric cleavage was initiated as early as from the first cleavage, which triggered radiation-oriented progress from central to peripheral part. Decondensed sperm may pass through the cytoplasm during the initial stage of egg development. By employing this modified classification, it will be feasible to identify and to collect embryos at various intrauterine stages.
Cleavage Events and Sperm Dynamics in Chick Intrauterine Embryos
Differing from mammals, many unfertilized supernumerary sperm heads were observed in the yolk area, as well as in the cytoplasm. Arrows in B1 indicate decondensed sperm nuclei. In mammals, asymmetric, polarized cleavage signs the initiation of differentiation, while in chick, each part of the preblastoderm being separated was still connected to each other at the ventral side even after initial furrowing. Chick embryos begin normal development after numerous sperm penetrate the oocyte cell membrane, suggesting that supernumerary sperm may be important to ensure karyogamy [ 14 ].
ДЛЯ ПОДТВЕРЖДЕНИЯ, ЧТО ВЫ СТАРШЕ 18-ТИ, ПОЖАЛУЙСТА, АВТОРИЗИРУЙТЕСЬ ЧЕРЕЗ ВК
Description: Decondensed sperm may pass through the cytoplasm during the initial stage of egg development. Polyspermic fertilization, with large numbers of decondensed or condensed sperm in an oocyte, was observed. The center region and the periphery region were designated for laterally closed cells and open cells, respectively. Several sperm heads in the yolk were undergoing decondensation.