Epiblast


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epiblast

[′ep·ə‚blast]
(embryology)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Epiblast

 

(1) In botany, a squamous growth on the outer side of the embryo of many herbs. The epiblast covers the plumule partially or completely. It is well expressed in most bread grains and meadow grasses, for example, rice, Poa, barley, and bamboo. It is absent in millet, sorghum, corn, and canes. The epiblast protects the plumule. During germination it swells greatly, accumulating moisture like a sponge and participating in dehiscence of the caryopsis. The morphological nature of the epiblast is unclear.

(2) In zoology, the outer epithelial layer of the discoblastula, or blastoderm, in scorpions, cephalopods, mollusks, sharks, and bony fishes, as well as in most reptiles, birds, and lower mammals. The epiblast contains ectodermal and mesodermal material. It is isolated from the cells of the internal layer, or hypoblast, by a cavity known as the blastocoel.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Mouse embryo has the shape of an egg cylinder (showing the apposition the epiblast and visceral endoderm tissues) and human embryo has the shape of a flat disc with two layers of cells known as epiblast and hypoblast.
Two-layered structure appeared with an outer the epiblast and inner hypoblast (Table VI).
Notably, mice mutant for lamcl, which do not form the initial laminin 111 network which is normally found in the epiblast, also do not form an organized collagen IV network; instead, collagen IV was detected in aggregates throughout the embryo [46].
LOS ANGELES, Calif, October 24, 2013 -- Researchers have long been searching for biotech's version of the fountain of youth: ways to encourage embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs) to endlessly self-renew, or divide to produce more stem cells.
"The mouse cells that we utilized, which are pluripotent epiblast stem cells, can make any cell type in body," explained Paul Tesar, an assistant professor of genetics at Case Western Reserve and senior author of the stud.
Epiblast The cells that give rise to the three germ layers of the embryo (ectoderm, mesoderm, and endoderm).
Stern hypothesizes that local movement in the epiblast, the epithelial cells, are "responsible for positioning and shaping the primitive streak" by pushing in among neighboring cells and this "can also explain the polonaise movements without the need for long-range gradients" (p.
Embryo development is rapid and the different organs such as scutellum, epiblast, vascular bundle, and root apex are differentiated by 6 DAF.
This migration occurs along the anterior-posterior portions of the epiblast--a portion of the inner cell mass--and the concentration of migrating cells results in the visible "primitive streak," which, while having a polarity ("cephalic," or head, and "caudal," or tail), is at this point merely a transitory part of the epiblast. Only at the end of the cells' migration through the primitive streak to their appropriate places within the embryo does a structure emerge, called the "neural fold." The neural fold marks the beginning of the central nervous system.
Embryonic stem cells can also adopt different stem cell states, depending on culture conditions mimicking the signalling conditions of embryonic environments at either blastocyst or epiblast stages; yet, cultured cells show epigenetic changes compared to their embryonic counterparts [9].
Then, in 2007, researchers discovered a new type of primitive mouse stem cell known as an epiblast stem cell, derived from cells just a couple of days older than classic mouse ESCs.
"The mouse cells that we utilized, which are pluripotent epiblast stem cells, can make any cell type in body," said Paul Tesar, an assistant professor of genetics at Case Western Reserve and senior author of the study.