(n.) The external skin or outer layer of an animal or plant, this being formed in an animal from the epiblast. See Illust. of Blastoderm.
Example Sentences:
(1) Here we report direct measurements of protein kinase C (PKC) activity in uninduced ectoderm, and in neuroectoderm shortly after induction by the involuting mesoderm, in Xenopus laevis embryos.
(2) The Notch locus in Drosophila encodes a transmembrane protein required for the determination of cell fate in ectodermal cells.
(3) The factor was tested on Triturus alpestris by the implantation method, and on isolated ectoderm of Xenopus laevis in solution.
(4) 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.
(5) Cells falling off from ectoderm were observed in normally developing gastrulae of the newt, Cynops pyrrhogaster, in light microscopic examination.
(6) Anhidrotic ectodermal dysplasia is characterized by an absence of seromucous glands in the oropharynx and tracheobronchial tree, making children with this disease prone to viral and bacterial respiratory infections.
(7) The positive reaction for keratin and vimentin confirmed the presence of ectodermal and mesodermal elements respectively in the tumor.
(8) Examination of the two types of tissue fragments revealed that IS-treated ICMs almost invariably retained viable endoderm cells whereas MS-isolated ectoderms did so only exceptionally.
(9) In the present study, ectodermal explants from Xenopus blastulae were shown to have high affinity binding sites for 125I-aFGF (Kd = 1.4 X 10(-10) M).
(10) Ectoderm from Cynops pyrrhogaster reacts like that of Ambystoma when exposed to LiCl, but like Triturus ectoderm it is insensitive to cyclic nucleotides.
(11) Several mouse mutants in the distal region of the mouse t-complex affecting blastocyst and embryonic ectoderm formation also map to this region.
(12) PTN mRNA was also strongly expressed in the basal layers of the tongue epithelium, which is the only epithelium and ectodermal derivative to express PTN mRNA, and this only after birth.
(13) These genes encode membrane proteins with epidermal growth factor repeats and are essential in the decision of an embryonic ectodermal cell to take on the fate of neuroblast or epidermoblast.
(14) We have found that competence of the ectoderm to respond to induction is lost at the same early neurula stage for all three marker genes.
(15) Multiple hamartoma syndrome, also known as Cowden's disease, is a rare genodermatosis with multiple organ system involvement affecting tissues derived from ectodermal, endodermal, and mesodermal tissue layers.
(16) From the right wing bud of stage 19 and 20 (HH) embryos the rim ectoderm was removed in four ways: all of the rim, the anterior third, the middle third (most of the A.E.R.
(17) During feather follicle formation, N-CAM was expressed in the dermal papilla and was closely apposed to the L-CAM-positive papillar ectoderm, while the dermal papilla showed no evidence of laminin or fibronectin.
(18) Initially each primordium forms a shallow depression in the ectodermal surface.
(19) From stage 110 on, a basement membrane differentiates beneath a one-cell thick subperipheral layer, which thus becomes the ectodermal basal layer, the prospective epidermal basal layer.
(20) CAT mRNA was observed in gut, mesenchyme cells and oral ectoderm in these embryos.
Endoderm
Definition:
(n.) The inner layer of the skin or integument of an animal.
(n.) The innermost layer of the blastoderm and the structures derived from it; the hypoblast; the entoblast. See Illust. of Ectoderm.
Example Sentences:
(1) In contrast, F9ACC19, an endodermal cell line derived from F9 cells, synthesizes only minor amounts of lactosaminoglycans and a high proportion of smaller glycopeptides.
(2) Both genes are expressed in the fetal liver, gut, and visceral endoderm of the yolk sac and are repressed shortly after birth in the liver and gut.
(3) Examination of the two types of tissue fragments revealed that IS-treated ICMs almost invariably retained viable endoderm cells whereas MS-isolated ectoderms did so only exceptionally.
(4) LIF inhibits differentiation under several conditions which lead to endodermal and mesodermal cell lineages including skeletal and cardiac muscle.
(5) This epithelial cell was tentatively identified as primitive extraembryonic endoderm by its ultrastructural appearance and its possession of cytokeratin intermediate filaments.
(6) The majority of testicular germ cell tumors in adults are accompanied by neoplastic intratubular germ cells; these cells were uniformly absent in ten pure yolk sac tumors (endodermal sinus tumors) of the testicle in children studied morphologically and immunohistochemically.
(7) After the treatment in toto of the embryos from various species of Anura by cAMP, the number of primordial germ cells (PGC) in genital ridges is strongly reduced; the most part of the PGC are found in the endoderm.
(8) Our experience suggests that the optimal management of patients with primary mediastinal endodermal sinus tumor requires an aggressive multidisciplinary approach guided by the extent of the tumor and the serum tumor marker levels.
(9) The tissues of the endodermal and mesodermal origin were also present in small quantities.
(10) Although the liver first forms as a discrete epithelial bud of endodermal tissue at stage 12-14 (45-53 h after laying), canaliculi were first detected by our antibodies at low levels in 4-day embryos and at high levels in stage 27 (5 days after laying) and later embryos.
(11) The cell cycle time of the gland cells appears to be longer than that of the epithelial cells of the endoderm throughout the animal.
(12) As development proceeded during primitive streak stages, the visceral and parietal endoderm became positively stained.
(13) The F9 cell is a mouse embryonal teratocarcinoma which can be induced to differentiate into visceral endoderm by treatment with retinoic acid (RA).
(14) Multiple hamartoma syndrome, also known as Cowden's disease, is a rare genodermatosis with multiple organ system involvement affecting tissues derived from ectodermal, endodermal, and mesodermal tissue layers.
(15) This finding suggests the identification of a cell population that is analogous to parietal endoderm in some eutherian animals.
(16) We recently showed that yolk sac is involved in the control of metabolism and action of vitamin D in the fetoplacental unit, since its endodermal cells contain a 24-hydroxylase for vitamin D metabolites and the 1,25-dihydroxyvitamin D receptor.
(17) These data thus demonstrate the production and presence of RBP mRNA and TTR mRNA, and the synthesis and secretion of RBP and TTR, by F9 cell embryoid bodies (specifically by visceral endoderm-like cells).
(18) We conclude that yolk-sac-derived teratomas are of endodermal origin because of the fact that the paternal X chromosome is inactivated in the yolk sac endoderm, whereas in the yolk sac mesoderm, as in the embryo, the inactivation is at random.
(19) A particularly interesting proteinase active at alkaline pH values is detected in the trophoblast-endoderm complex.
(20) It is therefore considered that, although there is good evidence that serum AAT is produced by endodermal sinus tumour elements, serum AAT is not a useful monitor of disease activity in these patients, especially when compared with serum AFP, the value of which is well recognized.