scholarly journals THE DEPENDENCE OF HEAD CURVATURE ON THE DEVELOPMENT OF THE HEART IN THE CHICK EMBRYO

1937 ◽  
Vol 14 (2) ◽  
pp. 229-231 ◽  
Author(s):  
C. H. WADDINGTON
Keyword(s):  
Chick Embryo ◽  
Blood Vessels ◽  
Brain Region ◽  
Normal Development ◽  
Anterior Part ◽  
Blood System ◽  
Chick Embryos ◽  
Aortic Arches ◽  
The Brain

1. The heart was removed from chick embryos of seven to twelve somites, and the embryos cultivated in vitro. The operation abolished the normal twisting of the anterior part of the embryo on to its left side and the general bending of the brain region into an arc. These two processes therefore seem to be dependent on the normal development of the heart. 2. The embryos showed a bending of the forebrain relative to the midbrain, which is therefore independent of the development of the heart. 3. The embryonic blood system, including the aortic arches, developed normally in many cases, but the blood vessels became enormously dilated. 4. The lateral evaginations of the foregut and the visceral arch mesenchyme underwent the first stages of differentiation in atypical positions, seemingly independently of each other or of any other structures.

Primordial germ cells in normal and transected duck blastoderms

Development ◽  
1968 ◽  
Vol 20 (3) ◽  
pp. 247-260
Author(s):  
Teresa Rogulska
Keyword(s):  
Chick Embryo ◽  
Blood Vessels ◽  
Germ Cells ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
Primitive Streak ◽  
Experimental Investigations ◽  
Suggestive Evidence ◽  
Area Pellucida

Suggestive evidence for the extragonadal origin of germ cells in birds was first presented by Swift (1914), who described primordial germ cells in the chick embryo at as early a stage as the primitive streak. According to Swift, primordial germ cells are originally located extra-embryonically in the anterior part of the blastoderm and occupy a crescent-shaped region (‘germinal crescent’) on the boundary between area opaca and area pellucida. Swift also found that primordial germ cells later enter into the blood vessels, circulate together with the blood throughout the whole blastoderm and finally penetrate into the genital ridges, where they become definitive germ cells. Swift's views have been confirmed in numerous descriptive and experimental investigations. Among the latter, the publications of Willier (1937), Simon (1960) and Dubois (1964a, b, 1965a, b, 1966) merit special attention. Dubois finally proved that the genital ridges exert a strong chemotactic influence on the primordial germ cells.

scholarly journals Effect of cortisol acetate on collagen biosynthesis and on the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase in chick-embryo tendon cells

1977 ◽  
Vol 164 (3) ◽  
pp. 533-539 ◽  
Author(s):  
A Oikarinen
Keyword(s):  
Chick Embryo ◽  
Enzyme Activities ◽  
Collagen Synthesis ◽  
Enzyme Synthesis ◽  
Prolyl Hydroxylase ◽  
Chick Embryos ◽  
Isolated Cells ◽  
Lysyl Hydroxylase ◽  
Tendon Cells

Collagen synthesis and the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase were studied in isolated chick-embryo tendon cells after the administration of cortisol acetate to the chick embryos. When the steroid was injected 1 day before isolation of the tendon cells, collagen synthesis was decreased, even though the enzyme activities were not changed. When cortisol acetate was given as repeated injections over a period of 4 days, both collagen synthesis and the enzyme activities decreased. The hydroxylase activities decreased even more than the two collagen glycosyltransferase activities, both in isolated cells and in whole chick embryos. The amount of prolyl hydroxylase protein diminished to the same extent as the enzyme activity, indicating that cortisol acetate inhibits enzyme synthesis. The inhibitory effect of cortisol acetate on collagen synthesis and on the enzyme activities was partially reversible in 3 days. Total protein synthesis was completely restored within this time. Only massive doses of cortisol acetate inhibited collagen synthesis in vitro. Additional experiments indicated that cortisol acetate did not decrease the rate of the enzyme reactions when added directly to the enzyme incubation mixtures. The results suggest that cortisol acetate decreases collagen synthesis both by its direct effect on collagen polypeptide-chain synthesis and by decreasing the activities of enzymes involved in post-translational modifications.

The Effect of Chloroacetophenone on Chick Embryos Cultured in vitro

Development ◽  
1962 ◽  
Vol 10 (3) ◽  
pp. 373-382
Author(s):  
M. S. Lakshmi
Keyword(s):  
Xenopus Laevis ◽  
Average Length ◽  
Primitive Streak ◽  
Poultry Farm ◽  
Chick Embryos ◽  
Normal Process ◽  
Strong Emphasis ◽  
The Brain

Brachet's (1950) strong emphasis on the role of —SH-containing proteins in the process of induction has stimulated a study of the interference in the normal process of morphogenesis of chick embryos by chloroacetophenone, which has been described by Beatty (1951) as a specific and irreversible —SH inhibitor. He studied the effect of chloroacetophenone on the development of embryos of Rana and Triturus employing different concentrations. Deuchar (1957) also studied the action of the same chemical on the embryos of Xenopus laevis and has recorded abnormalities mainly in the brain and the eye. In the present work ω-chloroacetophenone (CAP) commercially known as phenacyl chloride (ω—C6H5.CO.CH2Cl) was employed. The sample used was a B.D.H. product. Fresh fertilized hens' eggs brought from a local poultry farm were incubated at 37·5° C. for 16 to 18 hours to obtain definitive primitive-streak stages (range of length from 1·75 mm. to 2 mm.) or for about 22 hours to obtain head-process stages (average length of the head process alone 0·56 mm.).

Impaired energy metabolism as an initial step in the mechanism for 6-aminonicotinamide-induced limb malformation

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 217-222
Author(s):  
Yal C. Sheffield ◽  
Robert E. Seegmiller
Keyword(s):  
Amino Acid ◽  
Energy Metabolism ◽  
Chick Embryo ◽  
Chondroitin Sulfate ◽  
Atp Synthesis ◽  
Initial Step ◽  
Chick Embryos ◽  
Impaired Energy Metabolism ◽  
All Treatment

The analogue and antagonist of nicotinamide, 6-aminonicotinamide (6-AN), impairs cartilage formation and results in shortening of the limbs when administered to chick embryos. Studies have shown that 6-AN forms an abnormal NAD analogue which inhibits the activity of NAD-dependent enzymes associated with production of ATP. To determine if an effect on ATP synthesis might be associated with the mechanism of teratogenesis in the chick embryo, ATP levels of cartilage from day-8 chick embryos treated in vitro were assayed in relation to biosynthesis of protein, DNA and chondroitin sulfate. Incorporation of 35SO4− was inhibited by 6 h of treatment with 10 µg/ml of 6-AN, whereas incorporation of [3H]thymidine and [3H]amino acid was not inhibited until 12 h. Incorporation of [3H]- glucosamine was increased at all treatment times. A decrease in the level of ATP preceded any detectable inhibition of precursor incorporation. These results are consistent with the hypothesis that 6-AN inhibits chondroitin sulfate synthesis through a reduction in the level of ATP in chondrocytes.

scholarly journals In vitro crystallization of ribosomes from chick embryos.

1982 ◽  
Vol 95 (2) ◽  
pp. 648-653 ◽  
Author(s):  
R A Milligan ◽  
P N Unwin
Keyword(s):  
Chick Embryo ◽  
Ribosomal Subunit ◽  
Chick Embryos ◽  
Two Dimensional ◽  
Large Ribosomal Subunit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Full Complement ◽  
Polymorphic Forms

A new two-dimensional ribosome crystal, having the tetragonal space group P42(1)2 (a = 593 A), has been grown from ribosome tetramers extracted from hypothermic chick embryos. It is of particular interest because of its larger size (up to 3 x 3 micron2) and greater stability compared to other related polymorphic forms, and because it can easily be grown in large amounts. X-ray diffraction shows the order in the crystal to extend to a resolution of at least 60 A. The crystalline ribosomes appear to contain a full complement of small and large ribosomal subunit proteins and an additional four proteins not characteristic of chick embryo polysomes.

Ultrastructure of Blood Vessels of the Area Pellucida of Control and X-irradiated Chick Embryos

1968 ◽  
Vol 26 ◽  
pp. 118-119
Author(s):  
Margaret H. Sanderson ◽  
S. Phyllis Steamer
Keyword(s):  
Endothelial Cells ◽  
Chick Embryo ◽  
Blood Vessels ◽  
Vascular System ◽  
Smooth Endoplasmic Reticulum ◽  
Chick Embryos ◽  
In Ovo ◽  
Stage Of Development ◽  
Mesenchyme Cells ◽  
Area Pellucida

The chick embryo exposed to lethal doses of ionizing radiations develops a fatal circulatory failure within a few hours. This report describes the blood vessels of the area pellucida (a part of the extra-embryonic membranes of the chick embryo) and the effect of 250 kVp x-radiation upon them.Three-day chick embryos, x-irradiated in ovo with 1000-1200 R, were fixed 1-2 hours after exposure. The area pellucida is a multi-layered membrane consisting of ectoderm, somatic and splanchnic mesoderm, and endoderm (Fig. 1). The vascular system arises from the splanchnic mesoderm. The walls of small and medium-sized vessels are composed of endothelial cells, an occasional pericyte and processes of adjacent mesenchyme cells. Types of vessels cannot be distinguished at this stage of development; a basement membrane is seen only in isolated areas. The wall appears double or triple-layered, but the endothelium is frequently less than 0.1 micron thick (Fig. 2). Endothelial cells contain a large complement of polyribosomes, mitochondria, rough and smooth endoplasmic reticulum, a Golgi complex, pinocytotic vesicles and several kinds of inclusion bodies. The nucleus has a well-defined nucleolus.

An analysis of the aggregation and morphogenesis of area opaca endoderm cells from the primitive-streak chick embryo

Development ◽  
1979 ◽  
Vol 51 (1) ◽  
pp. 121-135
Author(s):  
Nadine Milos ◽  
Sara E. Zalik ◽  
Robert Phillips
Keyword(s):  
Cell Adhesion ◽  
Chick Embryo ◽  
Intrinsic Property ◽  
Primitive Streak ◽  
Chick Embryos ◽  
Embryonic Cells ◽  
Thin Walls ◽  
Cell Layers ◽  
Aggregative Behaviour

The aggregative behaviour and subsequent morphogenesis of extra-embryonic endoderm cells from primitive-streak chick embryos have been investigated. A relatively pure population of area opaca endoderm cells was obtained by differential dissociation, which involves partial separation of epiblast and endoderm cell clumps by sieving through Nitex mesh. For aggregation studies cells were cultured in rotating flasks in Leibovitz (L-15) medium, in saline or in saline supplemented with glucose (1 mg/ml). Aggregation was monitored using the Coulter Counter. In these three media aggregation is rapid; by 10 min an average of 61% of the population had aggregated, to reach a plateau at 30 min when an average percent adhesion value of 83 % was obtained. The aggregates in L-15 medium were large and compact. After several days in culture, they cavitated and formed smooth hollow vesicles with thin walls composed of one or a few cell layers. Aggregates formed in PCS were smaller and looser in appearance; the addition of glucose resulted in a certain degree of compaction. Some morphogenesis occurred under these conditions with the aggregates developing numerous irregular cavities. These experiments suggest that some of the factors that affect cell adhesion in early embryonic cells can be studied in vitro. The results also indicate that the ability to cavitate is an intrinsic property of the endoderm cells of the area opaca since this occurs in the absence of epiblast or mesoderm.

Hepatic induction in the avian embryo: Specificity of reactive endoderm and inductive mesoderm

Development ◽  
1981 ◽  
Vol 63 (1) ◽  
pp. 111-125
Author(s):  
Sumiko Fukuda-Taira
Keyword(s):  
Tissue Specificity ◽  
Normal Development ◽  
Mouse Embryos ◽  
Avian Embryo ◽  
Chick Embryos ◽  
Cardiac Region ◽  
Myocardial Layers ◽  
Cardiac Mesoderm

Mesoderm of precardiac and cardiac region (‘cardiac’ mesoderm) of chick, quail and mouse embryos could induce hepatic epithelium in the endoderm of the anterior half of young quail or chick embryos (anterior endoderm) in vitro as well as in vivo. No species specificity in the induction of hepatic epithelium by the ‘cardiac’ mesoderm could be observed. The hepatic induction, was controlled strictly by tissue specificity of both endoderm and mesoderm. Replacement of the ‘cardiac’ mesoderm or the anterior endoderm by noncardiac mesoderms or endoderms other than the anterior endoderm resulted in failure of hepatic induction. Only the anterior endoderm was found to have competence for hepatic induction, indicating that it was committed, in unknown ways, to react with ‘cardiac’ mesoderm, and can properly be called pre-hepatic endoderm. Comparison between the development of hepatic endoderm and the hepatic induction potency of ‘cardiac’ mesoderm, which was most intense during 1- to 1·5- incubation days and decreased gradually with the increase of the stage, suggests that in normal development the ‘cardiac’ mesoderm actually induces hepatic epithelium in the competent endoderm. Hepaticinduction potency remained up to 6 days, and was found in truncus arteriosus, ventricle and auricle areas and in endocardial and myocardial layers of the heart.

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