(n.) Epibolic invagination. See under Invagination.
Example Sentences:
(1) After 1 day in vitro the explants were partly encircled by epithelium which had proliferated from the cut edges of the explant and from rete ridges near the cut edge (epiboly).
(2) RA was applied for one hour at concentrations ranging from 10(-9) to 10(-6) M to embryos at 50% epiboly, the midgastrula stage, and at 10(-7) M to embryos at early and late gastrula stages.
(3) (1) Radial cell intercalations during epiboly mix cells located deeply in the blastoderm among more superficial ones.
(4) When two deep blastomeres make contact during epiboly stages, they soon break the contact and move apart; they overlap one another only rarely.
(5) These results suggest that epiboly of the EVL may have an active component as well as a passive one.
(6) The most striking of these alterations is the persistence throughout gastrulation of a thick blastocoel roof composed of many cell layers, suggesting that there is an inhibition of posterior spreading of the roof normally associated with epiboly.
(7) Morphometric analysis shows that about half the narrowing of the margin of the EVL during epiboly is accounted for by cell rearrangement and the other half by the associated tapering and narrowing.
(8) In addition to differentiation, keratinocyte migration over the sides of the explant (epiboly) and epithelial proliferation as determined by [3H]thymidine autoradiography were reduced by culture in low calcium medium.
(9) Gastrulae at 50% epiboly exposed continuously to DFP at concentrations between 40 microM and 90 microM completed epiboly, but exhibited a dose-dependent decrease in the number of somites formed, and a parallel decrease in the caudal extent of somite innervation, by 24 hours post-fertilization (h).
(10) Studies of vitronectin on cultured keratinocytes showed that it caused spreading and epiboly but not cellular adhesion to the substratum.
(11) When epiboly of the EVL and the yolk syncytial layer (YSL) commences (stage 14), deep blastomeres clump together as a consolidation mass and then migrate outward as single cells on the YSL.
(12) Implanted skin in the cat's bulla failed to develop a pearl formation but frequently developed an epiboly, in which case the epidermis receded and was partly replaced by mucous membrane, and its stroma was heavily invaded by mucous epithelium, resembling tubular glands.
(13) Using measured pieces of mouse ear skin epithelial outgrowth about floating explants (epiboly) and from adherent explants was studied.
(14) At 100% epiboly, fluorescent cells were located in contact with the YSL within the embryo proper, with the brightest fluorescence in the future head region.
(15) The present report describes Lucifer Yellow (LY) transfer between the syncytial layer of the yolk cell (YSL) and blastodermal cells during epiboly in the teleost fish Barbus conchonius.
(16) Epiboly, involution and convergent extension in zebrafish involve the same kinds of cellular rearrangements as in amphibians, and they occur during comparable stages of embryogenesis.
(17) The domains may signal specification of morphogenesis rather than cell fate, because, shortly after they appear, each assumes a different role during epiboly, the first morphogenetic movement of the embryo.
(18) The two most reliable tests, based on the distance from each deep blastomere within a selected area to its nearest neighboring cell, indicate that the distribution pattern changes from regular during epiboly stages to random during dispersed stages 1 and 2.
(19) Early development in Cynolebias resembles that of other South American annual fishes, such as Austrofundulus, in that a phase of deep blastomere dispersion and reaggregation spatially and temporally separates epiboly from embryogenesis.
(20) The presence, location and morphology of cells containing nuage, an ultrastructural characteristic of primordial germ cells (PGCs), is described from the moment of first morphological recognition of PGC (around 100% epiboly) in embryos of the teleost fish Barbus conchonius.
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.