scholarly journals Trilaminar Embryonic Disc

2020 ◽  
Author(s):  
Keyword(s):  
Embryonic Disc

Second Week: Formation of the Embryonic Disc

Embryogenesis ◽  
1971 ◽  
pp. 18-19 ◽  
Author(s):  
H. Tuchmann-Duplessis ◽  
G. David ◽  
P. Haegel
Keyword(s):  
Embryonic Disc

The Action of Various Agents upon the Rabbit Embryo

Development ◽  
1961 ◽  
Vol 9 (3) ◽  
pp. 468-491
Author(s):  
C. E. Adams ◽  
Mary F. Hay ◽  
Cecilia Lutwak-Mann
Keyword(s):  
Histological Examination ◽  
Severe Damage ◽  
Purine Analogues ◽  
Embryonic Disc ◽  
Rabbit Embryo

In the course of an investigation on the uptake of labelled ions by the rabbit embryo and its environment (Lutwak-Mann, Boursnell, & Bennett, 1960), experiments were done on pre-implantation blastocysts obtained from rabbits which had been treated parenterally with certain purine analogues. Histological examination of such blastocysts by the method of Moog & Lutwak-Mann (1958) showed that, as a result of treatment of the pregnant animals, the embryos had incurred severe damage chiefly localized in the embryonic disc. This observation prompted a wider study, reported below, of the action of various agents upon the early rabbit embryo, following their administration to the mother. Our investigation was chiefly concerned with the pre-implantation 6½-day-old blastocyst, but 5- and 7-day embryos were also examined. At the same time we have studied the influence of some of these agents upon ovulation, fertilization, and cleavage, as well as on implantation and later stages of pregnancy.

Transmission electron microscopy (TEM) of equine conceptuses at 14 and 16 days of gestation

2010 ◽  
Vol 22 (2) ◽  
pp. 405 ◽  
Author(s):  
Ingrid Walter ◽  
Waltraud Tschulenk ◽  
Sven Budik ◽  
Christine Aurich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Specific Cell ◽  
Fluid Uptake ◽  
Embryonic Disc ◽  
Transmission Electron ◽  
Cellular Junctions ◽  
Endodermal Cells ◽  
Specific Cell Surface

The present study gives a detailed ultrastructural description of equine conceptuses at Day 14 (n = 2) and Day 16 (n = 3) after ovulation. Whereas on Day 14 only primitive structures were seen, on Day 16 neurulation and formation of mesodermal somites had taken place. The ectoderm of the embryo itself and the surrounding trophoblast ectodermal cells were characterised by specific cell surface differentiations. At the embryonic ectodermal cell surface (14 and 16 days) remarkable protruded and fused cytoplasmic projections were seen, typically associated with macropinocytotic events involved in macromolecule and fluid uptake. This finding adds an important point to the expansion mode of the hypotone equine conceptus, which is characterised by ‘uphill’ fluid uptake. Numerous microvilli and coated endocytotic pits at the apical trophoblast membrane emphasised its absorptive character. Endodermal cells were arranged loosely with only apically located cellular junctions leaving large intercellular compartments. At the border of the embryonic disc apoptotic cells were regularly observed indicating high remodelling activities in this area. Conspicuous blister-like structures between ectoderm and mesoderm were seen in the trilaminar part of Day-14 and -16 conceptuses. These were strictly circumscribed despite not being sealed by cellular junctions between germinal layers. It is possible that these blisters are involved in embryo positioning; however, further studies are needed to verify this.

193CHARACTERIZATION OF PORCINE TROPHECTODERM-DERIVED CELLS IN THE PRESENCE OF HBMP4 IN THE ABSENCE OF A FEEDER LAYER

2004 ◽  
Vol 16 (2) ◽  
pp. 218 ◽  
Author(s):  
K.B. Stewart ◽  
A.M. Adams ◽  
S.L. Pratt ◽  
S.L. Stice
Keyword(s):  
Extracellular Matrix ◽  
Cell Growth ◽  
Cell Biology ◽  
Collagen Type ◽  
Growth Characteristic ◽  
Calf Serum ◽  
Embryonic Stem ◽  
Collagen Type Iv ◽  
Type Iv ◽  
Embryonic Disc

A porcine trophoblastic cell line could provide a powerful model for understanding trophoblast cell biology as well as placental gene expression and proteomics in vitro. In this experiment, we derived porcine trophoblastic cells from trophectoderm tissue and assessed their growth on three different extracellular matrix substrates and in three different concentrations of human recombinant bone morphogenetic protein 4 (hBMP4). Human BMP4 has been shown to induce differentiation of human embryonic stem cells into trophoblast lineages. Elongated embryos were flushed using DPBS supplemented with 1% fetal calf serum and penicillin-streptomycin (1X) from the hysterectomized uteri of superovulated and bred prepuberal gilts 15 days post-insemination. The embryonic disc was visualized with a dissecting microscope. The trophectoderm tissue was cut 2–3mm away from the embryonic disc with a scalpel and the trophectoderm tissue was manually dissected into cell aggregates. These aggregates were plated on collagen type IV, Matrigel, and human extracellular matrix (laminin, collagen type IV and heparan sulfate proteoglycan derived from human placenta) in culture medium (DMEM with 15% FCS, 0.1mM 2-mercaptoethanol, 4ngmL−1 basic FGF4 and 1X P/S) in the presence or absence of hBMP4 at 0, 10, or 20ngmL−1. Cell outgrowth was observed within 24 hours of culture. After three days of culture, various cell types (based on size and morphology) were present. Among cultures of predominant large cells were colonies of smaller cells with epithelial-type morphology that had a prominent nucleus and a high nuclear-to-cytoplasmic ratio. The epithelial-type cells grew in tight colonies with definite borders and contained cytoplasmic structures resembling lipid-containing vesicles. These colonies initially appeared on all matrices across all hBMP4 concentrations. After seven days in culture the colonies developed distinct differences across groups. Cell growth on collagen was comprised of tight colonies having definite borders among large cells. Colonies on collagen were larger and more pronounced in both the hBMP4-supplemented groups than when cultured without hBMP4. The Matrigel coated plates contained large sheets of epithelial-type cell growth instead of compact colonies. This type of growth characteristic was present in all hBMP4 treatments on Matrigel. In contrast, few cells survived and propagated on human extracellular matrix. Only small colonies having the desired morphology were among the large cells on human extracellular matrix when cultured in medium containing 10ngmL−1 hBMP4. Cells were passaged and only cells growing on Matrigel could be further cultured. These data suggest that both the cell substrate and hBMP4 affect initial trophoblast outgrowths. Further analysis including immunocytochemistry and RT-PCR is currently being performed to better characterize these cells. Epidemiology/Diseases

Embryonic disc development and subsequent viability of cattle embryos following culture in two media under two oxygen concentrations

2004 ◽  
Vol 16 (8) ◽  
pp. 787 ◽  
Author(s):  
A. E. Fischer-Brown ◽  
B. R. Lindsey ◽  
F. A. Ireland ◽  
D. L. Northey ◽  
R. L. Monson ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Latin Square ◽  
Bovine Embryos ◽  
Morphological Evaluation ◽  
Embryonic Disc ◽  
Developmental Capacity ◽  
Series Of Experiments ◽  
Oxygen Concentrations

Bovine embryos were produced in vitro using a 2 × 2 design of modified medium (KSOM or SOF) and oxygen concentration (5% or 20%). Day 7 blastocysts were transferred in bulk (n = 11, on average) to recipient heifers and recovered non-surgically at Day 14. In two replications of a Latin square, eight heifers received embryos from each combination of factors. Recovered embryos were evaluated for trophoblast length and width, as well as the presence and diameter of an embryonic disc (ED). An ED was detected in a higher percentage of embryos that had been cultured in KSOM than SOF (72% v. 46%, respectively; P < 0.05). The aim of a second series of experiments was to associate Day 14 morphology with subsequent developmental capacity. In vitro-produced blastocysts were transferred (n = 17–20) on Day 7 to each of eight heifers and recovered at Day 14. Thirty-eight blastocysts were retransferred to heifers following morphological evaluation. Embryos in which an ED with no signs of degeneration had been detected maintained more pregnancies than other embryos in which an ED had either shown signs of degeneration or had not been detected (5/8 v. 2/30, respectively; P < 0.01). Further investigation into ED integrity at the elongating stage may contribute to our understanding of pregnancy establishment and maintenance.

scholarly journals Morphological characterization of pre- and peri-implantation in vitro cultured, somatic cell nuclear transfer and in vivo derived ovine embryos

Reproduction ◽  
2005 ◽  
Vol 130 (5) ◽  
pp. 681-694 ◽  
Author(s):  
P Tveden-Nyborg ◽  
T T Peura ◽  
K M Hartwich ◽  
S K Walker ◽  
P Maddox-Hyttel
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Morphological Characterization ◽  
Morphological Development ◽  
Embryonic Disc ◽  
Transmission Electron

The processes of cellular differentiation were studied in somatic cell nuclear transfer (SCNT), in vitro cultured (IVC) and in vivo developed (in vivo) ovine embryos on days 7, 9, 11, 13, 17 and 19. SCNT embryos were constructed from in vitro matured oocytes and granulosa cells, and IVC embryos were produced by in vitro culture of in vivo fertilized zygotes. Most SCNT and IVC embryos were transferred to recipients on day 6 while some remained in culture for day 7 processing. In vivo embryos were collected as zygotes, transferred to intermediate recipients and retransferred to final recipients on day 6. All embryos were processed for examination by light and transmission electron microscopy or immunohistochemical labelling for alpha-1-fetoprotein and vimentin. Overall, morphological development of in vivo embryos was superior to IVC and SCNT embryos. Day 7 and particularly day 9 IVC and SCNT embryos had impaired hypoblast development, some lacking identifiable inner cell masses. On day 11, only in vivo and IVC embryos had developed an embryonic disc, and gastrulation was evident in half of in vivo embryos and one IVC embryo. By day 13, all in vivo embryos had completed gastrulation whereas IVC and SCNT embryos remained retarded. On days 17 and 19, in vivo embryos had significantly more somites and a more developed allantois than IVC and SCNT embryos. We conclude that IVC and particularly SCNT procedures cause a retardation of embryo development and cell differentiation at days 7–19 of gestation.

Oxidation of

1993 ◽  
Vol 5 (2) ◽  
pp. 201 ◽  
Author(s):  
RG Wales ◽  
EE Waugh
Keyword(s):  
Yolk Sac ◽  
Metabolic Energy ◽  
Embryonic Tissue ◽  
Co2 Production ◽  
Acetate Metabolism ◽  
Embryonic Disc ◽  
Extraembryonic Membranes

Acetate metabolism by the sheep conceptus was assessed by measuring CO2 production during a 2.5-h incubation of embryos and samples of the extraembryonic membranes in HEPES-buffered media containing 1.12 mM [U-14C]acetate. The rate of oxidation of acetate by embryonic tissue showed little change between Days 13 and 15 of pregnancy but greatly decreased by Days 17 and 19. By contrast, oxidation of the substrate by the trophoblast increased substantially with development and was five times the early rate by Day 19. Oxidation of acetate by the yolk sac also increased 4-fold between Days 17 and 19. The addition of glucose to incubations of extraembryonic membranes resulted in some reduction in the oxidation of acetate by the yolk sac and allantois but had little effect on the trophoblast. At Days 13 and 15, the rate of oxidation of acetate by the embryonic disc was 6-7 times that by the trophoblast. As development progressed, this situation was reversed and by Day 19 the trophoblast metabolized more than five times the amount of acetate per microgram than did the Day-19 embryo. Although acetate metabolism by yolk sac and allantois on Day 17 was low, its metabolism by the yolk sac increased to values similar to those for the trophoblast at Day 19 but its utilization by the allantoic membrane remained low. Comparison of the estimates of ATP generated from acetate by these tissue with those published for glucose demonstrates that acetate is much less effective than glucose for the provision of metabolic energy.

Changes in structure of the trophectoderm of a marsupial in Mid-pregnancy up to the time of implantation

1996 ◽  
Vol 8 (4) ◽  
pp. 797 ◽  
Author(s):  
CT Roberts ◽  
WG Breed
Keyword(s):  
Toluidine Blue ◽  
Functional Activity ◽  
Cell Structure ◽  
Morphological Differentiation ◽  
Trophoblast Differentiation ◽  
Squamous Cells ◽  
Sminthopsis Crassicaudata ◽  
Embryonic Disc ◽  
Columnar Cells ◽  
Yolk Sac Placenta

Pre- and peri-implantation embryos of the dasyurid marsupial Sminthopsis crassicaudata were examined for morphological differentiation of the trophectoderm. The cells of unilaminar blastocysts were all squamous and stained intensely with toluidine blue. In bilaminar blastocysts and embryos at the early embryonic-disc stage, the trophectoderm was similar in appearance to, but stained more lightly than, the underlying endoderm. Trophoblast differentiation did not appear to occur until the mesoderm had begun to migrate between the trophoblast and endoderm beyond the embryonic disc. At this stage, trophoblasts had three distinct morphologies: (1) vacuolated, tall and columnar cells in the trilaminar region; (2) large cuboidal cells in the adjacent bilaminar region; and (3) squamous cells in the abembryonic pole of the bilaminar region. These variations in cell structure correlate with differences in subsequent functional activity in these three regions of the yolk sac placenta.

Cleavage and gastrulation in the egg-brooding, marsupial frog, Gastrotheca riobambae

Development ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 223-232
Author(s):  
Richard P. Elinson ◽  
Eugenia M. Del Pino
Keyword(s):  
Vital Staining ◽  
Yolk Sac ◽  
Small Cells ◽  
Size Difference ◽  
Animal Pole ◽  
Embryonic Disc ◽  
Slow Development ◽  
Vegetal Pole ◽  
Egg Brooding ◽  
Marginal Region

The marsupial frog Gastrotheca riobambae has several reproductive adaptations, most prominent of which is the incubation of the embryo in a pouch on the mother's back. We have followed cleavage and gastrulation by microscopical observation and by vital staining, and have found several alterations in these processes which may reflect the reproductive adaptations. The large, yolky egg has a cap of yolk-poor cytoplasm at the animal pole which is incorporated into a translucent blastocoel roof consisting of a single cell layer. The epithelium of the yolk sac is derived from the roof. The inconspicuous blastoporal lips form near the vegetal pole from cells of the marginal region. Gastrulation movements include the epibolic stretching of the surface towards the blastopore and a contraction of the vegetal surface. The blastoporal lips close over a small archenteron, and the cells of the lips become the embryonic disc, a discrete group of small cells which give rise to most of the embryo's body. The great size difference between animal and vegetal blastomeres during cleavage, the single-celled blastocoel roof, the dissociation in time between archenteron formation and its expansion, the embryonic disc and the slow development distinguish G. riobambae embryos from those of other frogs. The importance of the marginal region which produces the embryonic disc and the unimportance of the most animal region whose fate is primarily yolk sac emphasizes the role of the marginal region in amphibian development.

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