The results revealed that Sox5 transcript was detected at very low levels in embryos at early stages up to the gastrula, but was then upregulated and reached peak expression in the neurula
stage, and then was slightly downregulated between tail-bud and hatching.
Patterns of gene expression suggest that initial left-right asymmetry is established at the late gastrula/early neurula
by nodal expression in anterior somites on the left and later in endoderm on the left together with the expression of the nodal antagonist, lefty, on the right (Yu et al., 2002; Onai et al, 2010, 2012).
A twofold destructive/proliferative action of injury itself is fundamental in the organizative phenomena during the late blastula, gastrula and neurula
stages, as shown in the Bufo arenarum species when specimens are submitted to experimental exogenous injury.
Further studies will compare the effects of both all-trans and 9-cis retinoic acid on early neurula
Table 1 Schedule for development of Asymmetron lucayanum at 27[degrees]C, with notes on embryonic and larval behavior Stage Time after Figure fertilization 1- and 2-cell 1 h 5A-C 4- and 8-cell 2 h 5D 16- and 32-cell 3 h not shown 64- and 128-cell 4 h not shown Blastula 5 h 5E Mid gastrula 9 h 5F Late gastrula (a) 12 h 5G-I (b) Just-hatched neurula
15 h 5J-L Early neurula
19 h 5M, N Mid neurula
(c) 24 h 5O Late neurula
(d) 32 h 5P, Q Hatchet-shaped embryo (d), (c) 50 h 5R-Y Early larva (mouth just open) (f) 3 days 5Z-Z"; 6A-F Feeding larva 5 days 6G-Q (a) Newly produced ectodermal cilia cause embryo to rotate in fertilization envelope.
Electron microscopic study of the development of amphioxus Branchiostoma belcheri tsingtauense: the neurula
Six plasmid cDNA libraries were prepared for EST sequencing, two from mixed blastual and gstrula stages, two from mixed late gastrula and neurula
stages, and two from juvfeniles with 2-3 gill slits.
Furthermore, homologs of neural plate border specifiers Msx, Zic, and Pax3/7 are present within the neural plate border territory in late gastrula/early neurula
, suggesting that the initial steps of the border patterning and specification are already present in cephalochordates (Holland et al., 1999; Sharman et al., 1999; Gostling and Shimeld, 2003).
The search identified numerous clones of GFP from unfertilized egg, gastrula, neurula
, larval, and adult libraries for B.
Cell-lineage of the larval nervous system in the ascidian Ciona intestinalis: neurula
stage through to hatched larva.
These genes are initially expressed in the involuting mesoderm of the gastrula, then in the differentiating somites of the neurula
, followed by the differentiating notochord and finally in the tail bud of the 10-somite stage embryo (15).
Retinoic acid modifies the pattern of cell differentiation in the central nervous system of neurula
stage Xenopus embryos.