(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.
Metazoan
Definition:
(n.) One of the Metazoa.
Example Sentences:
(1) Because ctenophore and all other known metazoan mtDNA is circular, the shared occurrence of linear mtDNA in three of the four cnidarian classes suggests a basal position for the Anthozoa within the phylum.
(2) There is also some evidence that this exists in metazoan cells and is perhaps involved in neoplastic transformation.
(3) The origin of metazoa implies the passage from an eukarote protozoan to a protozygote ancestor of a metazoan zygote.
(4) The protein genes are the same as 12 of the 13 protein genes found in other metazoan mtDNAs: Cyt b, cytochrome b; COI-III, cytochrome c oxidase subunits I-III; ATPase6, Fo ATPase subunit 6; ND1-6 and 4L, NADH dehydrogenase subunits 1-6 and 4L: a gene for ATPase subunit 8, common to other metazoan mtDNAs, has not been identified in nematode mtDNAs.
(5) Yeast counterparts of the metazoan spliceosomal snRNAs (U1, U2, U4, U5 and U6) have been identified but, with the exception of U6, the yeast snRNAs are larger and sequence similarity is limited to short regions.
(6) PCR also proved to be a rapid method for identifying homeobox sequences from diverse metazoan species.
(7) The earliest metazoans, when symmetrical at all, were probably radial in symmetry.
(8) The most probable hypothesis is that of a symbiotic origin of the first zygote by association of two protists one signifying a spherical oocell and the other a flagellated spermatozoan; this could be the first step of the metazoan ontogenesis and therefore also of the phylogenesis.
(9) A summary of the metazoan parasites reported from A. rufa is included.
(10) Comparison of the sequences obtained from the different species indicate that the metazoan lineages all appear to have arisen at approximately the same time and significantly later than the time of divergence of yeast from the common ancestor of the Metazoa.
(11) Movements, manifest as changes in cell arrangements and shape, are an integral part of metazoan development.
(12) The role of convergent extension in gastrulation of other amphibians and other metazoans and its significance to related problems in early development are discussed.
(13) The structure of Pit-1 and its recognition elements suggests that metazoan tissue phenotype is controlled by a family of transcription factors that bind to related cis-active elements and contain several highly conserved domains.
(14) We also mutagenized a portion of the yeast core subdomain, a region conserved in primary and secondary structure among several yeast species but absent from the much smaller metazoan U1 molecule.
(15) Although multiple infections often confounded interpretation it was concluded that the major infectious diseases, of approximately equal importance, were coccidiosis, bacterial septicaemia with Gram-negative organisms, and metazoan parasitism including ascariasis and pentastomiasis.
(16) This work demonstrates that conversion takes place at an appreciable frequency between tandem repeats in metazoan germline.
(17) PI did not cochromatograph with any of the catecholamines commonly thought to be involved in immune responses of dipterans against metazoan parasites, suggesting that it may be a unique substrate for these reactions.
(18) Formation of the 3' end of U1 and U2 small nuclear RNA (snRNA) precursors is directed by a conserved sequence called the 3' box located 9 to 28 nucleotides downstream of all metazoan U1 to U4 snRNA genes sequenced so far.
(19) Cloning of three Antennapedia-related sequences from cnidarians provides evidence of ancient roles for homeobox genes early in metazoan evolution.
(20) Implications of a replicon basis for chromatin structure-function and the evolution of metazoan organisms are considered.