(n.) The outer layer of the blastoderm; the ectoderm. See Blastoderm, Delamination.
Example Sentences:
(1) Expansion of the cell sheet following attachment, and the fusion of epiblasts advancing toward each other, does not require the presence of mineralocorticoid.
(2) At the midgastrula stage the epiblast cells have the highest dry weight due to the highest protein concentration in the cytoplasm and the biggest cell volume.
(3) Proliferation occurs throughout the extra-embryonic epiblast during the expansion period.
(4) These observations are consistent with an epiblast origin for the avian germ line, and are strikingly similar to those reported for the early mouse embryo using the same antibody (Hahnel & Eddy, 1986).
(5) IGFBP-2 mRNA was detected throughout the epiblast of the egg cylinder as early as e7, when IGF-II expression was restricted to trophectoderm and other extraembryonic cells.
(6) It is also noted that the inadequate differentiation of the epiblast and endoderm would not have been apparent without microscopic examination.
(7) Both X chromosomes continued to replicate synchronously in the embryonic ectoderm or epiblast at this stage.
(8) The resulting space is not homologous with the primordial amniotic cavity; instead, it is a transitory tropho-epiblastic cavity.
(9) After the yolk has been covered, the epiblast continues to grow, with proliferation restricted largely to band just distal to the advancing edge of the area vasculosa.
(10) Primordial germ cells in the mouse are known to be derived from the epiblast.
(11) In general, the dorsoventral orientation of the previously induced epiblast was retained, but the orientation of the competent epiblast cells was more flexible and could be influenced by the neighbouring neuralised cells.
(12) The results of this study show that the epiblast cells of chick blastoderm at Hamburger-Hamilton stage 1 contain macrobodies which themselves contain particles resembling the 'lining bodies' described by Bellairs.
(13) At one time presumed to be derived from a common "neural" ancestor, all are now deemed to be "neuroendocrine-programmed," arising either in the embryonic epiblast itself or in one of its principal descendants.
(14) Epiblastic cells never gave rise to skeletal myotubes.
(15) The definitive amniotic epithelium forms by the upfolding and mitotic proliferation of the margins of the epiblastic disc; this process is completed in 11-day rhesus, and 9-day human, blastocysts.
(16) At 108 h and 120 h pc the polar trophoblast (Rauber's layer) is an intact epithelium overlying the epiblast of the inner cell mass.
(17) The epiblast cells of the optic bud do not migrate into the brain and the lamina is formed by the proliferation of the central imaginal disc.
(18) By the time of primitive streak formation (stage 4-5) the dorsal surface of the epiblast displayed increased binding sites, while the frequency of sites on the ventral surface of the endoblast was reduced.
(19) A microinjection technique is described for fate mapping the epiblast of avian embryos.
(20) Injection in situ of a short-term lineage label (horse radish peroxidase) into single epiblast cells at 6.7 days p.c.
Gastrulation
Definition:
(n.) The process of invagination, in embryonic development, by which a gastrula is formed.
Example Sentences:
(1) Birthdates of neurons were obtained from autoradiograms of animals receiving tritiated thymidine from gastrulation through 1 month after metamorphosis.
(2) Evx-1 RNA is first detected shortly before the onset of gastrulation in a region of ectoderm containing cells that will soon be found in the primitive streak.
(3) The embryos incubated in vitro at the from blastula stage are characterized by the sharp activation of protein synthesis and the vegetal-animal gradient of protein synthesis, as well as in the control embryos; such embryos gastrulate and proceed to primary differentiation.
(4) Thus, the area with separated HL, which is restricted to the region of the PMC released at the stage of PMC ingression, spreads almost entirely throughout the area of the indenting vegetal plate at gastrulation.
(5) On the basis of hystological studies a description of fission and gastrulation in Microsomacanthus paramicrosoma (gasowska, 1931) is given.
(6) This contrasts with embryos ventralized by UV-irradiation and suggests that XBMP-4-induced ventralization occurs after the onset of gastrulation.
(7) Several lines of experimental evidence indicate that contact with the animal pole locus, or "target" region, is crucial for the change in phenotype of the SMCs: (1) the phenotypic change can be induced precociously by bringing the animal pole region within reach of the tip of the archenteron early in gastrulation.
(8) Gastrulation is accompanied by a sharp increase in the AChE activity which was most pronounced in anterior hypoblast.
(9) In the present study, it was found that cytotactin is first present in the gastrulating chicken embryo.
(10) Experiments are described that examine the state of organisation of the presumptive mesoderm and ectoderm of the Xenopus embryo at stages up to the onset of gastrulation.
(11) As a result, there is a loss of the 'compacted' epithelial surface of the blastula, an inability to close a wounded surface and defective gastrulation.
(12) (d) Tenascin blocks cell adhesion to FN in vitro and gastrulation in vivo.
(13) In contrast, in vitro activity of mannosylphosphoryldolichol synthase, another enzyme in the pathway of N-linked glycosylation, was maximal in membranes from egg and embryos in the early stages of development and declined prior to gastrulation.
(14) As an immediate consequence of neural induction during gastrulation, some neuroectodermal cells acquire the ability to develop a number of specific neuronal and astroglial features, without requiring subsequent chordamesodermal cues.
(15) After gastrulation additional novel non-oogenetic proteins were synthesized for most stages examined.
(16) An analysis of changes in cell shape during the initial phase of gastrulation indicates that there is a stage-dependent shift from cells being columnar to having their apices skewed toward the vegetal plate and an increase in the proportion of cells having basal processes during gastrulation.
(17) In view of the hypocalcaemic properties of calcitonin and the importance of calcium ions in cell aggregation, this phenomenon has been attributed to an alteration in cell adhesion which results in faulty cell migration during gastrulation with consequent abnormalities of the prechordal region of the archenteron roof and the overlying neural plate.
(18) Microtubule distribution was examined in whole mounts of Drosophila embryos from the cellularization of the syncytial blastoderm (stage 6) to the completion of the gastrulation (stage 7) by fluorescence microscopy.
(19) These changes in the dynamic properties of the lipid probe HEDAF during gastrulation suggest that the lipid phase of the plasma membrane of these ectodermal cells undergo structural changes.
(20) In Lytechinus, the late appearing histone, H1g, begins to be synthesized at gastrulation.