Vasculogenesis in the early quail
blastodisc as studied with a monoclonal antibody recognizing endothelial cells.
Zygote to cleavage phase began from 0-1 h to 4 h after post fertilization and one day after post fertilization, it characterized with cytoplasmic growth, formation of
blastodisc at the end of animal pole, presence of different perivitelline gape and cleavage phase categorized with a sequence of meiotic partitions that resulted in several blastomeres.
One hour after fertilisation, the cytoplasm was pulled toward the animal pole, and a
blastodisc was formed (1-cell stage) (Fig.
A small circular spot on the upper surface of the yolk mass is detected, it's considered as the
blastodisc. There are also collapsed fat droplets under it (Fig.
The beginning of gastrula marks the end of the blastula stage, and it is followed by epiboly, defined as the movement of the yolk syncytial layer and
blastodisc around the yolk cell.
Gradually the blastoderm formed into several layers due to further cell division which is called
blastodisc. At this stage a space was formed between yolk and blastoderm which is called blastocoel.
On the contrary, avian PGCs originate from the central zone of
blastodisc [23, 26-29] and then migrate anteriorly to extraembryonic region called "germinal crescent" [23, 26].
Early cell divisions were evident at the animal pole (opposite of the oil droplet) and eventually formed the
blastodisc. Divisions progressed until individual blastomeres were no longer distinguishable.
Earliest stage of eggs with asymmetrical
blastodisc (Table 3), though the asymmetry may be an artifact of preservation.
The embryonic developmental stage was ranked as 0 = no embryos present beneath the abdomen; 1 = only yolk visible (newly spawned); 2 =
blastodisc present but no eye pigmentation; 3 = eye pigmentation or eye development visible, cephalothorax and pleon not separated; or 4 = egg present, little yolk, carapace and pleon separate (Bauer and Delahoussaye, 2008).
During this period dividing cells were easily distinguishable prior to
blastodisc formation, and little change in morphometry occurs.
A mathematical technique for estimating
blastodisc: yolk volume ratios instead of egg sizes.
blastodisc - a layer of cells on the inside of the blastula