scholarly journals CELL CYCLE IN THE PRIMITIVE STREAK AND THE NOTOCHORD OF EARLY CHICK EMBRYOS

1969 ◽  
Vol 10 (3-4) ◽  
pp. 297-311 ◽  
Author(s):  
KENJIRO OZATO
Keyword(s):  
Cell Cycle ◽  
Primitive Streak ◽  
Chick Embryos

The Effect of Chloroacetophenone on the Inducing Capacity of Hensen's Node

Development ◽  
1962 ◽  
Vol 10 (3) ◽  
pp. 383-388
Author(s):  
M. S. Lakshmi
Keyword(s):  
Organizer Region ◽  
High Capacity ◽  
Primitive Streak ◽  
Chick Embryos

In a previous paper (Lakshmi, 1962) the effects of ω-chloroacetophenone (CAP), which is an irreversible —SH inhibitor, on the morphogenesis of chick embryos cultured in vitro were reported. Brachet (1950) suggested that the —SH-containing proteins might be active in induction. Rapkine & Brachet (1951) studied the effect of monoiodoacetate on the amphibian organizer and observed that the organizer region retained a high capacity for induction despite treatment with the inhibitor. The action of monoiodoacetate is reversible, hence it was felt desirable to investigate the action of CAP on the living organiser of chick, namely Hensen's node. Chick embryos at the primitive-streak stage were explanted in vitro by New's (1955) technique. These were treated with 0·0005 M CAP for 15 and 30 minutes, 0·001 M CAP for 15 minutes, and 0·0015 M CAP for 15 minutes. 0·1 ml. of the solution was added to the endodermal surface of the explanted embryos.

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.).

Cell proliferation in the developing wing-bud of normal and talpid3 mutant chick embryos

Development ◽  
1975 ◽  
Vol 34 (3) ◽  
pp. 589-607
Author(s):  
D. A. Ede ◽  
O. P. Flint ◽  
P. Teague
Keyword(s):  
Cell Cycle ◽  
Early Stage ◽  
Mitotic Rate ◽  
Mitotic Division ◽  
Chick Embryos ◽  
Division Rate ◽  
Cell Cycle Time ◽  
Continuous Sampling ◽  
Wing Bud ◽  
Marked Drop

Previous measurements on mitotic division rate or cell cycle time have been made on samples from a few discrete limb regions or by continuous sampling, but only down a unidimensional limb axis, disregarding morphological discontinuities such as the presence or absence of cartilage. This study presents a new analysis on normal and talpid3 mutant chick embryos, measuring mitotic rate and also cell density through the central proximo-distal axis and at the limb periphery, taking into account the development of cartilage regions. Differentiation of cartilage is correlated with a marked drop in mitotic rate, accounting for a proximo-distal gradient of mitosis in central counts which was not observed at the limb periphery. Talpid3 limbs at an early stage show a central mitotic gradient, but the reverse of that observed in normal limbs.

scholarly journals Experiments on Embryonic Induction

1934 ◽  
Vol 11 (3) ◽  
pp. 212-217
Author(s):  
C. H. WADDINGTON
Keyword(s):  
Primitive Streak ◽  
Neural Plate ◽  
Chick Embryos ◽  
Embryonic Induction ◽  
Gut Endoderm

It is shown that the ectoderm of the area opaca of chick embryos of the primitive streak stage can react to primitive streak grafts by the formation of an induced neural plate. The conclusion is drawn that the competence to form neural plate is not conferred on ectoderm by the gut endoderm, which determines the formation of the primitive streak.

Hox-4 gene expression in mouse/chicken heterospecific grafts of signalling regions to limb buds reveals similarities in patterning mechanisms

Development ◽  
1992 ◽  
Vol 115 (2) ◽  
pp. 553-560 ◽  
Author(s):  
J.C. Izpisua-Belmonte ◽  
J.M. Brown ◽  
A. Crawley ◽  
D. Duboule ◽  
C. Tickle
Keyword(s):  
Gene Expression ◽  
Gene Network ◽  
Primitive Streak ◽  
Mouse Embryos ◽  
Limb Bud ◽  
Chick Embryos ◽  
Mouse Limb ◽  
Mouse Cells ◽  
Species Specific ◽  
Genital Tubercle

The products of Hox-4 genes appear to encode position in developing vertebrate limbs. In chick embryos, a number of different signalling regions when grafted to wing buds lead to duplicated digit patterns. We grafted tissue from the equivalent regions in mouse embryos to chick wing buds and assayed expression of Hox-4 genes in both the mouse cells in the grafts and in the chick cells in the responding limb bud using species specific probes. Tissue from the mouse limb polarizing region and anterior primitive streak respecify anterior chick limb bud cells to give posterior structures and lead to activation of all the genes in the complex. Mouse neural tube and genital tubercle grafts, which give much less extensive changes in pattern, do not activate 5′-located Hox-4 genes. Analysis of expression of Hox-4 genes in mouse cells in the grafted signalling regions reveals no relationship between expression of these genes and strength of their signalling activity. Endogenous signals in the chick limb bud activate Hox-4 genes in grafts of mouse anterior limb cells when placed posteriorly and in grafts of mouse anterior primitive streak tissue. The activation of the same gene network by different signalling regions points to a similarity in patterning mechanisms along the axes of the vertebrate body.

Differential mitosis and degeneration patterns in relation to the alterations in the shape of the embryonic ectoderm of early post-implantation mouse embryos

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 33-51
Author(s):  
R. E. Poelmann
Keyword(s):  
Cell Cycle ◽  
Cell Kinetics ◽  
Tritiated Thymidine ◽  
Primitive Streak ◽  
Cell Number ◽  
Mouse Embryos ◽  
Surface Ectoderm ◽  
Dividing Cells ◽  
Post Implantation ◽  
Embryonic Ectoderm

The shape of the embryonic ectoderm of early post-implantation mouse embryos changes greatly in the period of 6·2–7·3 days post coitum. The subcellular morphology of the embryonic ectoderm remains unchanged, except in the primitive-streak region. Cell kinetics differ between ectodermal regions. These differences may be related to the changes in the shape of the ectoderm. The increase in cell number in the lateral ectoderm (the prospective surface ectoderm) exceeds that in the frontal ectoderm (the future neurectoderm). This is not due to differences in the duration of the cell cycle. It can be explained, however, by the occurrence of different relative numbers of dividing and non-dividing cells. These numbers vary between the two regions. The percentage of non-dividing cells in the frontal ectoderm may reach 45, whereas in the lateral ectoderm this percentage is not higher than 15. Autoradiography in tritiated thymidine-treated embryos combined with the mitotic indices gave us all of the parameters necessary to present a model capable of clarifying the growth of the ectoderm during gastrulation, as well as the changes in the shape of the ectoderm.

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