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.

The metabolism of glutamine by the preimplantation sheep conceptus and its interaction with glucose

1994 ◽  
Vol 6 (6) ◽  
pp. 659 ◽  
Author(s):  
RG Wales ◽  
ZF Du
Keyword(s):  
Glucose Oxidation ◽  
Fold Increase ◽  
Insoluble Fraction ◽  
Yolk Sac ◽  
Embryonic Tissue ◽  
Additive Effects ◽  
Stages Of Development ◽  
Early Stages ◽  
Extraembryonic Membranes ◽  
Trophoblastic Tissue

The metabolism of glutamine and glucose, separately and in combination, by the sheep conceptus recovered on Days 2, 6, 13, 15, 17, and 19 of pregnancy was assessed over 2.5 h. At Day 2, the production of CO2 from glutamine was similar to that from glucose, with additive effects seen when both substrates were present. Between Day 2 and Day 6, there was a three-fold increase in glucose oxidation but no change in the oxidation of glutamine. From Day 13 to Day 19, the oxidation of glutamine was relatively high in embryonic tissue, low in trophoblastic tissue and intermediate in the yolk sac but in all tissues decreased as development progressed. Over this latter period the oxidation of glutamine was reduced to approximately 50% by the addition of glucose to the medium but glucose oxidation was unaffected by the addition of glutamine. At the early stages of development, the incorporation of substrate carbon from glutamine was less than that from glucose but in each case, incorporation into the acid-insoluble macromolecular fraction increased 2-3 times between Day 2 and Day 6. Incorporation of glutamine into the Day-17 and Day-19 conceptus was also measured; embryonic tissue exhibited the highest rate of incorporation and trophoblastic tissue the lowest. Incorporation was lower on Day 19 than on Day 17 and the proportion of carbon isolated in the acid-insoluble fraction represented 20% of the total incorporated. At no time did the addition of glucose to the medium alter incorporation of glutamine into either embryonic tissue or extraembryonic membranes.

Characterization of protein production by caprine placental membranes: identification and immunolocalization of retinol-binding protein

1995 ◽  
Vol 146 (3) ◽  
pp. 527-534 ◽  
Author(s):  
K H Liu ◽  
J C Huang ◽  
J D Godkin
Keyword(s):  
Protein Production ◽  
Culture Medium ◽  
De Novo ◽  
Binding Protein ◽  
Yolk Sac ◽  
Retinol Binding Protein ◽  
Minimum Essential Medium ◽  
Placental Membranes ◽  
Extraembryonic Membranes

Abstract Caprine chorion, allantois and amnion from days 23, 28, 35, 39 and 45, and yolk sac from day 23 of pregnancy were isolated by dissection and cultured for 24 h in modified minimum essential medium in the presence of [35S] methionine. De novo-synthesized proteins released into the culture medium were analyzed by two-dimensional PAGE and fluorography. Patterns of protein production by these isolated extraembryonic membranes remained relatively unchanged from days 23 to 45 of pregnancy. Electrophoretic profiles of proteins synthesized by allantois and amnion were identical but distinct from that produced by chorion. Yolk sac was the major source of serum-like proteins. An acidic (pI 5·3–6·3) 22 kDa protein, which consisted of four isoelectric variants, was produced by all extraembryonic membranes and demonstrated to immunoreact with antiserum produced against bovine placental retinol-binding protein (RBP). Limited N-terminal sequence analysis of one major isoform indicated that the protein had complete homology with bovine RBP over the first 15 amino acids. Immunoreactive RBP was localized in epithelial cells lining the chorion, allantois and amnion. In this study, we have characterized and compared protein production by isolated extraembryonic membranes through days 23 to 45 of pregnancy and identified the 22 kDa protein as caprine RBP of placental origin. Journal of Endocrinology (1995) 146, 527–534

scholarly journals Embryonic Annexes

2018 ◽  
Vol 1 (4) ◽  
pp. 301-309
Author(s):  
Mariana Rojas ◽  
Ángel Rodríguez
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Chorionic Villus ◽  
Yolk Sac ◽  
Placental Lactogen ◽  
Mechanical Trauma ◽  
Temperature Changes ◽  
Suspensory Ligament ◽  
Different Types ◽  
Extraembryonic Membranes

In vertebrates, depending on the environment in which an embryo develops, different types of extraembryonic membranes are formed. In placental mammals the following extraembryonic membranes are formed: amnion, yolk sac, allantois, chorion and placenta. Extraembryonic membranes perform functions vital to the embryo. The amnion protects the embryo from drying, the mechanical trauma, temperature changes and adhesions which can distort it. The yolk sac is present in all vertebrates. In mammals allows the formation of the first blood vessels and the first blood, home to the primordial germ cells for some time; however, in fish and birds these have nutritional importance. In birds and mammals such as cattle, sheep and pig the allantois receives urinary wastes; this structure also contributes part of the bladder and at the time of birth becomes the suspensory ligament, urachus. The chorion form chorionic villus, which can produce hormones such as chorionic gonadotropin and human placental lactogen. A portion of the chorionic sac helps form the 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.

An in vitro study of functions of embryonic membranes in the rat

Development ◽  
1972 ◽  
Vol 27 (3) ◽  
pp. 533-542
Author(s):  
G. S. Payne ◽  
E. M. Deuchar
Keyword(s):  
Total Protein ◽  
In Vitro Study ◽  
Axial Rotation ◽  
Yolk Sac ◽  
Amniotic Cavity ◽  
Outer Membranes ◽  
Leucine Uptake ◽  
Visceral Yolk Sac ◽  
Extraembryonic Membranes

Ten-day rat embryos have been cultivated in vitro, with different layers of the extraembryonic membranes removed. The effects of presence or absence of each membrane on the morphology of the embryos, their histodifferentiation and their uptake of leucine into protein have been followed. Explants with all membranes left intact failed to expand fully and to undergo axial rotation of the embryo, but nevertheless showed highest total protein and highest leucine uptake in biochemical estimations and in autoradiographs. Explants with outer membranes removed and the visceral yolk sac left intact showed the most normal morphology and expansion of the extraembryonic cavities when compared with embryos removed from the uterus at 11·5 days” gestation, but they showed less protein and less leucine uptake than the first series. Explants in which the visceral yolk sac was removed underwent little growth or development and had low total protein values and radioactivity counts. The amnion collapsed and the amniotic cavity disappeared. When the amnion was removed there was a greater incidence of death, as well as little or no development, and lower radioactivity counts than in the first two series. It is concluded that the outer membranes and the visceral yolk sac play an important role in the transfer of small metabolites to the embryo, as well as in regulating the volume of the extraembryonic fluids.

The orderly allocation of mesodermal cells to the extraembryonic structures and the anteroposterior axis during gastrulation of the mouse embryo

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4691-4701 ◽  
Author(s):  
S.J. Kinder ◽  
T.E. Tsang ◽  
G.A. Quinlan ◽  
A.K. Hadjantonakis ◽  
A. Nagy ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Mouse Embryo ◽  
Primitive Streak ◽  
Yolk Sac ◽  
Cell Lineages ◽  
Anteroposterior Axis ◽  
Extraembryonic Mesoderm ◽  
Extraembryonic Membranes ◽  
Lateral Mesoderm ◽  
Late Stages

The prospective fate of cells in the primitive streak was examined at early, mid and late stages of mouse gastrula development to determine the order of allocation of primitive streak cells to the mesoderm of the extraembryonic membranes and to the fetal tissues. At the early-streak stage, primitive streak cells contribute predominantly to tissues of the extraembryonic mesoderm as previously found. However, a surprising observation is that the erythropoietic precursors of the yolk sac emerge earlier than the bulk of the vitelline endothelium, which is formed continuously throughout gastrula development. This may suggest that the erythropoietic and the endothelial cell lineages may arise independently of one another. Furthermore, the extraembryonic mesoderm that is localized to the anterior and chorionic side of the yolk sac is recruited ahead of that destined for the posterior and amnionic side. For the mesodermal derivatives in the embryo, those destined for the rostral structures such as heart and forebrain mesoderm ingress through the primitive streak early during a narrow window of development. They are then followed by those for the rest of the cranial mesoderm and lastly the paraxial and lateral mesoderm of the trunk. Results of this study, which represent snapshots of the types of precursor cells in the primitive streak, have provided a better delineation of the timing of allocation of the various mesodermal lineages to specific compartments in the extraembryonic membranes and different locations in the embryonic anteroposterior axis.

scholarly journals RNA-seq reveals conservation of function among the yolk sacs of human, mouse, and chicken

2017 ◽  
Vol 114 (24) ◽  
pp. E4753-E4761 ◽  
Author(s):  
Tereza Cindrova-Davies ◽  
Eric Jauniaux ◽  
Michael G. Elliot ◽  
Sungsam Gong ◽  
Graham J. Burton ◽  
...  
Keyword(s):  
Building Blocks ◽  
Yolk Sac ◽  
Coelomic Fluid ◽  
Rna Seq ◽  
Secondary Phases ◽  
Evolutionary Mechanisms ◽  
Proteomic Data ◽  
Phases Of Development ◽  
Extraembryonic Membranes ◽  
Shed Light

The yolk sac is phylogenetically the oldest of the extraembryonic membranes. The human embryo retains a yolk sac, which goes through primary and secondary phases of development, but its importance is controversial. Although it is known to synthesize proteins, its transport functions are widely considered vestigial. Here, we report RNA-sequencing (RNA-seq) data for the human and murine yolk sacs and compare those data with data for the chicken. We also relate the human RNA-seq data to proteomic data for the coelomic fluid bathing the yolk sac. Conservation of transcriptomes across the species indicates that the human secondary yolk sac likely performs key functions early in development, particularly uptake and processing of macro- and micronutrients, many of which are found in coelomic fluid. More generally, our findings shed light on evolutionary mechanisms that give rise to complex structures such as the placenta. We identify genetic modules that are conserved across mammals and birds, suggesting these modules are part of the core amniote genetic repertoire and are the building blocks for both oviparous and viviparous reproductive modes. We propose that although a choriovitelline placenta is never established physically in the human, the placental villi, the exocoelomic cavity, and the secondary yolk sac function together as a physiological equivalent.

Differentiation of the embryonic disc, amnion, and yolk sac in the rhesus monkey

1986 ◽  
Vol 177 (2) ◽  
pp. 161-185 ◽  
Author(s):  
Allen C. Enders ◽  
Sandra Schlafke ◽  
Andrew G. Hendrickx
Keyword(s):  
Rhesus Monkey ◽  
Yolk Sac ◽  
Embryonic Disc

Incorporation of glucose by the sheep conceptus between days 13 and 19 of pregnancy

1989 ◽  
Vol 1 (2) ◽  
pp. 137 ◽  
Author(s):  
RG Wales ◽  
CL Cuneo ◽  
EE Waugh
Keyword(s):  
Culture Medium ◽  
Soluble Fraction ◽  
Embryonic Disc ◽  
Lactate And Pyruvate ◽  
Extraembryonic Membranes

Incorporation of glucose into the internal biochemical pools of the sheep embryo and samples of extraembryonic membranes was measured during a 2.5 h incubation in the presence of radiolabelled glucose. Very little glucose was incorporated into the glycogen pools by either the embryo or its membranes and never represented more than 5% of total incorporation. Approximately 65% of label was isolated in the non-glycogen acid-soluble fraction of samples and the remainder was incorporated into non-glycogen macromolecules. The embryonic disc of the day-13 conceptus had the highest rate of incorporation per mg dried weight of any structure studied. Synthesis of non-glycogen macromolecules by the day-13 disc was five to six times that of either day-15 or day-17 embryos. On day 19 very low rates of incorporation into the isolated embryo were found during culture. Evidence suggests that this was a result of limitations on the diffusion of substrate into the embryo because incubation of fragmented embryos produced rates similar to those found on days 15 and 17. Incorporation of glucose into the intracellular pools of extraembryonic membranes per mg dried weight remained relatively low and stable over the period studied and there were only minor differences in the rate of incorporation between membranes. Incorporation of glucose by embryos and extraembryonic membranes was equally as good in phosphate-buffered media as in bicarbonate-buffered solutions and was unaffected by changes in the concentration of lactate and pyruvate in the culture medium.

Effect of oxygen concentration on the incorporation of glucose by the sheep conceptus between days 13 and 19 of pregnancy

1993 ◽  
Vol 5 (3) ◽  
pp. 317
Author(s):  
ZF Du ◽  
RG Wales
Keyword(s):  
Oxygen Concentration ◽  
Soluble Fraction ◽  
Embryonic Tissue ◽  
Initial Value ◽  
Glucose Carbon ◽  
O2 Concentration ◽  
Glucose Incorporation ◽  
Extraembryonic Membranes ◽  
Effect Of Oxygen ◽  
Sole Energy

Embryos and extraembryonic membranes recovered from the sheep conceptus on Days 13, 15, 17 and 19 of pregnancy were incubated in medium containing glucose as sole energy substrate. In all components of the conceptus 60-70% of substrate carbon incorporated was recovered in the non-glycogen acid-soluble fraction, 25-30% in non-glycogen macromolecules and 4-8% in the glycogen pools. At all stages of development examined, embryonic tissue accumulated more glucose carbon into all fractions than did yolk sac which in turn was more active than trophoblast. After its appearance, the allantois was at least as active in glucose incorporation as embryonic tissue. Over the period of development examined, incorporation into all tissues of the conceptus fell progressively as pregnancy advanced and, by Day 19, total incorporation was about 60% of the initial value for each component. Reduction in oxygen concentration generally depressed incorporation into all intracellular carbon pools. The most consistent and significant effects were recorded for the two non-glycogen pools where incorporation fell, on average, by 30-40% when O2 concentration was reduced to 1%. Most of the response observed was due to a drop in O2 concentration from 20 to 5% with smaller additional effects when the O2 was further reduced to 1%. Incorporation into all pools isolated tended to follow a similar pattern and incorporation into the three macromolecular components, expressed as a percentage of total incorporation, remained unchanged as O2 concentration was reduced.

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