Strong electrical currents leave the primitive streak of 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.

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The Effect of Chloroacetophenone on Chick Embryos Cultured in vitro

Development ◽

10.1242/dev.10.3.373 ◽

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.).

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

Development Growth & Differentiation ◽

10.1111/j.1440-169x.1969.tb00242.x ◽

1969 ◽

Vol 10 (3-4) ◽

pp. 297-311 ◽

Cited By ~ 10

Author(s):

KENJIRO OZATO

Keyword(s):

Cell Cycle ◽

Primitive Streak ◽

Chick Embryos

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Experiments on Embryonic Induction

Journal of Experimental Biology ◽

10.1242/jeb.11.3.212 ◽

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.

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

Development ◽

10.1242/dev.115.2.553 ◽

1992 ◽

Vol 115 (2) ◽

pp. 553-560 ◽

Cited By ~ 8

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.

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REGULATION OF THE INITIATION OF HEMOGLOBIN SYNTHESIS IN THE BLOOD ISLAND CELLS OF CHICK EMBRYOS: I. QUALITATIVE STUDIES OF THE EFFECTS OF ACTINOMYCIN AND δ-AMINOLEVULINIC ACID

Canadian Journal of Biochemistry ◽

10.1139/o66-175 ◽

1966 ◽

Vol 44 (11) ◽

pp. 1543-1560 ◽

Cited By ~ 20

Author(s):

S. D. Wainwright ◽

Lillian K. Wainwright

Keyword(s):

Aminolevulinic Acid ◽

Basal Medium ◽

Primitive Streak ◽

Chick Embryos ◽

Messenger Rnas ◽

Stages Of Development ◽

Linear Rate ◽

Hemoglobin Synthesis ◽

Naked Eye ◽

Somite Stage

Intact and de-embryonated blastodiscs of chick embryos from all stages of development between the definitive primitive streak and the 10-somite stage were incubated on simple solid synthetic media. On the basal medium, blastodiscs at all initial stages of development synthesized hemoglobin readily visible to the naked eye within 24 hours, incorporated leucine into protein at an approximately linear rate for 24 hours, and incorporated uridine into RNA at a roughly linear rate for at least 6 hours after a short lag.Blastodiscs taken before the 1-somite stage failed to synthesize any detectable hemoglobin on medium containing 2 μg/ml of actinomycin, whereas those token at later stages synthesized hemoglobin visible to the naked eye. This concentration of actinomycin totally inhibited the incorporation of uridine into high molecular weight RNA within 2–3 hours, but the incorporation of leucine into protein was not inhibited for 6–8 hours. The residual incorporation of uridine was entirely into the soluble RNA fraction.At 10 μg/ml, actinomycin markedly inhibited the synthesis of hemoglobin by blastodiscs taken at stages earlier than the 6-somite embryo, but did not markedly affect hemoglobin synthesis by the more advanced blastodiscs. This concentration of actinomycin caused only slightly greater inhibition of the incorporation of uridine into acid-precipitable material than the smaller concentration for all blastodiscs, and was not markedly more inhibitory for the incorporation of leucine into protein.The presence of δ-aminolevulinic acid overcame the inhibitions of synthesis of hemoglobin by actinomycin but did not prevent the inhibitions of incorporation of uridine into RNA and of leucine into protein.Regulation of the onset of rapid hemoglobin synthesis appears to be at the translation level, probably through the supply of δ-aminolevulinic acid. The latter is probably regulated through synthesis of RNAs formed at the head-fold stage. Messenger RNAs for globin synthesis are present at the stage of the definitive primitive streak.

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“Neighborhood watch” model: embryonic epiblast cells assess positional information in relation to their neighbors

10.1101/2021.04.22.440894 ◽

2021 ◽

Author(s):

Hyung Chul Lee ◽

Cato Hastings ◽

Nidia M.M. Oliveira ◽

Rubén Pérez-Carrasco ◽

Karen M. Page ◽

...

Keyword(s):

Primitive Streak ◽

Positional Information ◽

Experimental Manipulation ◽

Experimental Results ◽

The Other ◽

Chick Embryos ◽

Neighborhood Watch ◽

Alternative Models

AbstractIn many developing and regenerating systems, tissue pattern is established through gradients of informative morphogens, but we know little about how cells interpret these. Using experimental manipulation of early chick embryos including misexpression of an inducer (VG1 or ACTIVIN) and an inhibitor (BMP4), we test two alternative models for their ability to explain how the site of primitive streak formation is positioned relative to the rest of the embryo. In one model, cells read morphogen concentrations cell-autonomously. In the other, cells sense changes in morphogen status relative to their neighborhood. We find that only the latter model can account for the experimental results, including some counter-intuitive predictions. This mechanism (which we name “neighborhood watch” model) illuminates the classic “French Flag Problem” and how positional information is interpreted by a sheet of cells.TeaserHow do cells know their position in the embryo, to determine where gastrulation will start?

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Segregating expression domains of two goosecoid genes during the transition from gastrulation to neurulation in chick embryos

Development ◽

10.1242/dev.124.8.1443 ◽

1997 ◽

Vol 124 (8) ◽

pp. 1443-1452 ◽

Cited By ~ 7

Author(s):

L. Lemaire ◽

T. Roeser ◽

J.C. Izpisua-Belmonte ◽

M. Kessel

Keyword(s):

Posterior Margin ◽

Anterior Part ◽

Primitive Streak ◽

Neural Plate ◽

Chick Embryos ◽

Positive Part ◽

Full Extension ◽

Isolation And Characterization ◽

Chick Embryogenesis

We report the isolation and characterization of a chicken gene, GSX, containing a homeobox similar to that of the goosecoid gene. The structure of the GSX gene and the deduced GSX protein are highly related to the previously described goosecoid gene. The two homeodomains are 74% identical. In the first few hours of chick embryogenesis, the expression pattern of GSX is similar to GSC, in the posterior margin of the embryo and the young primitive streak. Later during gastrulation, expression of the two genes segregate. GSC is expressed in the anterior part of the primitive streak, then in the node, and finally in the pre-chordal plate. GSX is expressed in the primitive streak excluding the node, and then demarcating the early neural plate around the anterior streak and overlying the pre-chordal plate. We demonstrate that the GSX-positive part of the primitive streak induces gastrulation, while the GSC-expressing part induces neurulation. After full extension of the streak, the fate of cells now characterized by GSX is to undergo neurulation, while those expressing GSC undergo gastrulation. We discuss the effect of a duplicated basic goosecoid identity for the generation of a chordate nervous system in ontogeny and phylogeny.

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

Development ◽

10.1242/dev.51.1.121 ◽

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.

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