were observed and developed quickly to the gastrula stage within 2 days.
Skeletogenesis thus resembled development of typical feeding larvae, in which these spicules are secreted by a mass of primary mesenchyme cells that migrate into the blastocoel
shortly before the start of gastrulation (Okazaki 1975).
These differences are also shown in Figure 4A to E, where the HP or HA exposed groups exhibited embryo developmental morphology, blastocoel
cavity expansion, and embryo quality that were superior to the control.
During ingression, the motion of cells from the wall of the blastula into the blastocoel
is accompanied by changes in the expression of cell surface receptors.
5 h Eight-cell embryos 9 h 16-cell embryos 23 h Unhatched blastulae; wrinkled with a clear blastocoel
and irregular blastoderm 47 h * Hatched blastulae; apical tuft visible 73 h Initiation of gastrulation 4 days Mid-stage gastrulae; archenteron about 1/2 way into blastocoel
7 days Gastrulae that are compressed; first spicules visible with cross-polarized light 8 days Prisms 14 days Two-arm plutei with open mouths 33 days Four and six-arm plutei 48 days Formation of lobes begins 79 days Juvenile rudiments with podial buds and pedicellariae 120 days Metamorphosis; juvenile spine count ranges from 5 to 23 * Blastulae were unhatched at 23 and 33 h.
1 Degeneration -- -- Space between the trophoblast -- -- Expanded blastocoel
-- -- Degenerative cells between -- -- the ZP and trophoblasts Trophoblast Microvilli; long -- -- Microvilli; scanty -- -- Degeneration -- -- Lipid droplet; rich + + Lipid droplet; large (mm) (1) p+ 3 p+ 5.
was not visible within the blastula, suggesting that J.
At 9 h after spawning, embryos consisted of a bilayer of cells with no definite blastocoel
Effects of fetal calf serum, amino acids, vitamins and insulin on blastocoel
formation and hatching of in vitro and IVM/IVF derived porcine embryos developing in vitro.
Previous lectin-staining results demonstrated that the mesh-like structure of the extracellular matrix included acid mucopolysaccharides in the blastocoel
of the archenteron-forming P.
As the eggs have abundant small lipids, the blastomeres release lipids into the blastocoel
, causing an increase in cell number at the wrinkled-blastula stage and the embryonic surface becomes smooth (1).
, which first becomes apparent in the 8-cell stage, is very pronounced beginning with the 32-cell stage (Fig.
i] elevation in ciliary ectodermal cells of echinoplutei through a serotonin receptor cell network in the blastocoel
The ingression of cells into the blastocoel
at gastrulation requires those cells to undergo EMT, making the regulation of cell adhesion crucial for the normal development of the organism.
The cells stained weakly with P4 are seen in the blastocoel
of the six-armed pluteus (Fig.