scholarly journals Dynamics of Structural Barriers and Innate Immune Components during Incubation of the Avian Egg: Critical Interplay between Autonomous Embryonic Development and Maternal Anticipation

2018 ◽  
Vol 11 (2) ◽  
pp. 111-124 ◽  
Author(s):  
Maxwell T. Hincke ◽  
Mylène Da Silva ◽  
Nicolas Guyot ◽  
Joël Gautron ◽  
Marc D. McKee ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Innate Immune ◽  
Vitelline Membrane ◽  
Structural Barriers ◽  
Embryonic Tissues ◽  
Egg Incubation ◽  
Evolutionary Success ◽  
Protective Structures ◽  
Amniotic Membranes ◽  
Autonomous Development

The integrated innate immune features of the calcareous egg and its contents are a critical underpinning of the remarkable evolutionary success of the Aves clade. Beginning at the time of laying, the initial protective structures of the egg, i.e., the biomineralized eggshell, egg-white antimicrobial peptides, and vitelline membrane, are rapidly and dramatically altered during embryonic development. The embryo-generated extra-embryonic tissues (chorioallantoic/amniotic membranes, yolk sac, and associated chambers) are all critical to counteract degradation of primary egg defenses during development. With a focus on the chick embryo (Gallus gallus domesticus), this review describes the progressive transformation of egg innate immunity by embryo-generated structures and mechanisms over the 21-day course of egg incubation, and also discusses the critical interplay between autonomous development and maternal anticipation.

Mechanics of Embryonic Head Fold Morphogenesis

2008 ◽  
Author(s):  
Victor D. Varner ◽  
Dmitry A. Voronov ◽  
Larry A. Taber
Keyword(s):  
Embryonic Development ◽  
Incubation Period ◽  
Neural Plate ◽  
Vitelline Membrane ◽  
Heart Tube ◽  
Germ Layers ◽  
Embryonic Tissues ◽  
Anterior Extent ◽  
Insight Into ◽  
Embryonic Head

Head fold morphogenesis constitutes the first discernible epithelial folding event in the embryonic development of the chick. It arises at Hamburger and Hamilton (HH) stage 6 (approximately 24 hours into a 21-day incubation period) and establishes the anterior extent of the embryo [1]. At this stage, the embryonic blastoderm is composed of three germ layers (endoderm, mesoderm, and ectoderm), which are organized into a flat layered sheet that overlies the fibrous vitelline membrane (VM). Within this blastodermal sheet, a crescent-shaped head fold develops just anterior to the elongating notochord, spanning across the embryonic midline at the rostral end of neural plate. At the crest of this fold, the bilateral precardiac plates fuse in a cranial to caudal direction and give rise to the primitive heart tube and foregut [2, 3]. An understanding of head fold morphogenesis may thus offer insight into how embryonic tissues are arranged to make ready for proper cardiac formation.

Ultrastructural changes in the avian vitelline membrane during embryonic development

Development ◽  
1969 ◽  
Vol 21 (3) ◽  
pp. 467-484
Author(s):  
Cynthia Jensen
Keyword(s):  
Embryonic Development ◽  
Mechanical Strength ◽  
Dual Role ◽  
Early Embryonic Development ◽  
Ultrastructural Changes ◽  
Vitelline Membrane ◽  
Entire Surface ◽  
Animal Pole ◽  
The Third ◽  
Vegetal Pole

The vitelline (yolk) membrane of the avian egg plays a dual role during early embryonic development; it encloses the yolk and provides a substratum for expansion of the embryo (Fig. 1). Expansion appears to be dependent upon the movement of cells at the edge of the blastoderm which is intimately associated with the inner layer of the vitelline membrane (New, 1959; Bellairs, 1963). The blastoderm (embryonic plus extraembryonic cells) has almost covered the entire surface of the yolk by the third and fourth days of incubation, and when this stage has been reached the vitelline membrane ruptures over the embryo and slips toward the vegetal pole. Rupture of the membrane during development appears to be the consequence of a decrease in its mechanical strength (Moran, 1936), which changes most rapidly at the animal pole (over the embryo).

scholarly journals High air humidity is sufficient for successful egg incubation and early post‐embryonic development in the marbled crayfish ( Procambarus virginalis )

2019 ◽  
Vol 64 (9) ◽  
pp. 1603-1612 ◽  
Author(s):  
Wei Guo ◽  
Jan Kubec ◽  
Lukáš Veselý ◽  
Md Shakhawate Hossain ◽  
Miloš Buřič ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Air Humidity ◽  
Egg Incubation ◽  
Marbled Crayfish

scholarly journals The TALE Homeodomain Protein Pbx2 Is Not Essential for Development and Long-Term Survival

2004 ◽  
Vol 24 (12) ◽  
pp. 5324-5331 ◽  
Author(s):  
Licia Selleri ◽  
Jorge DiMartino ◽  
Jan van Deursen ◽  
Andrea Brendolan ◽  
Mrinmoy Sanyal ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Late Gestation ◽  
Homeodomain Protein ◽  
Mammalian Development ◽  
Term Survival ◽  
Long Term Survival ◽  
Embryonic Tissues ◽  
Adult Mice ◽  
Tale Homeodomain

ABSTRACT Pbx2 is one of four mammalian genes that encode closely related TALE homeodomain proteins, which serve as DNA binding partners for a subset of Hox transcription factors. The expression and contributions of Pbx2 to mammalian development remain undefined, in contrast to the essential roles recently established for family members Pbx1 and Pbx3. Here we report that Pbx2 is widely expressed during embryonic development, particularly in neural and epithelial tissues during late gestation. Despite wide Pbx2 expression, mice homozygous mutant for Pbx2 are born at the expected Mendelian frequencies and exhibit no detectable abnormalities in development and organogenesis or reduction of long-term survival. The lack of an apparent phenotype in Pbx2− /− mice likely reflects functional redundancy, since the Pbx2 protein is present at considerably lower levels than comparable isoforms of Pbx1 and/or Pbx3 in embryonic tissues. In postnatal bone marrow and thymus, however, Pbx2 is the predominant high-molecular-weight (MW)-isoform Pbx protein detectable by immunoblotting. Nevertheless, the absence of Pbx2 has no measurable effect on steady-state hematopoiesis or immune function in adult mice, suggesting possible compensation by low-MW-isoform Pbx proteins present in these tissues. We conclude that the roles of Pbx2 in murine embryonic development, organogenesis, hematopoiesis, immune responses, and long-term survival are not essential.

scholarly journals Downregulation of Extraembryonic Tension Controls Body Axis Formation in Avian Embryos

2021 ◽  
Author(s):  
Daniele Kunz ◽  
Anfu Wang ◽  
Chon U Chan ◽  
Robyn H. Pritchard ◽  
Wenyu Wang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Outer Layer ◽  
Shape Change ◽  
Body Axis ◽  
Vitelline Membrane ◽  
Axis Formation ◽  
Extraembryonic Tissue ◽  
Avian Embryos ◽  
Embryonic Tissues ◽  
Tissue Tension

AbstractEmbryonic tissues undergoing shape change draw mechanical input from extraembryonic substrates. In avian eggs, the early blastoderm disk is under the tension of the vitelline membrane (VM). Here we report that chicken VM characteristically downregulates tension and stiffness to facilitate stage-specific embryo morphogenesis. While early relaxation of the VM impairs blastoderm expansion, maintaining VM tension in later stages resists the convergence of the posterior body causing stalled elongation, open neural tube, and axis rupture. Biochemical and structural analysis shows that VM weakening follows the reduction of its outer-layer glycoprotein fibers, which is caused by an increasing albumen pH due to CO2 release from the egg. Our results identify a previously unrecognized mechanism of body axis defects through mis-regulation of extraembryonic tissue tension.

scholarly journals Preimplantation development in ungulates: a ‘ménage à quatre’ scenario

Reproduction ◽  
2020 ◽  
Vol 159 (3) ◽  
pp. R151-R172 ◽  
Author(s):  
Jérôme Artus ◽  
Isabelle Hue ◽  
Hervé Acloque
Keyword(s):  
Embryonic Development ◽  
Inner Cell Mass ◽  
Current Knowledge ◽  
Cell Mass ◽  
Extended Period ◽  
The Body ◽  
Critical Function ◽  
Embryonic Tissues ◽  
Wide Range ◽  
Implantation Period

In ungulates, early embryonic development differs dramatically from that of mice and humans and is characterized by an extended period of pre- and peri-implantation development in utero. After hatching from the zona pellucida, the ungulate blastocyst will stay free in the uterus for many days before implanting within the uterine wall. During this protracted peri-implantation period, an intimate dialog between the embryo and the uterus is established through a complex series of paracrine signals. The blastocyst elongates, leading to extreme growth of extra-embryonic tissues, and at the same time, the inner cell mass moves up into the trophoblast and evolves into the embryonic disc, which is directly exposed to molecules present in the uterine fluids. In the peri-implantation period, uterine glands secrete a wide range of molecules, including enzymes, growth factors, adhesion proteins, cytokines, hormones, and nutrients like amino and fatty acids, which are collectively referred to as histotroph. The identification, role, and effects of these secretions on the biology of the conceptus are still being described; however, the studies that have been conducted to date have demonstrated that histotroph is essential for embryonic development and serves a critical function during the pre- and peri implantation periods. Here, we present an overview of current knowledge on the molecular dialogue among embryonic, extraembryonic, and maternal tissues prior to implantation. Taken together, the body of work described here demonstrates the extent to which this dialog enables the coordination of the development of the conceptus with respect to the establishment of embryonic and extra-embryonic tissues as well as in preparation for implantation.

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