THE SECRETION AND THE ROLE OF INSULIN IN CHICK EMBRYOS AND CHICKENS

The role of the notochord in inducing and patterning adjacent neural and mesodermal tissues is well established. We provide evidence that the notochord is also required for one of the earliest known steps in the development of the pancreas, an endodermally derived organ. At a developmental stage in chick embryos when the notochord touches the endoderm, removal of notochord eliminates subsequent expression of several markers of dorsal pancreas bud development, including insulin, glucagon and carboxypeptidase A. Pancreatic gene expression can be initiated and maintained in prepancreatic chick endoderm grown in vitro with notochord. Non-pancreatic endoderm, however, does not express pancreatic genes when recombined with the same notochord. The results suggest that the notochord provides a permissive signal to endoderm to specify pancreatic fate in a stepwise manner.

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Measurements of cell adhesion

Development ◽

10.1242/dev.30.2.499 ◽

1973 ◽

Vol 30 (2) ◽

pp. 499-509

Author(s):

Janet E. Hornby

Keyword(s):

Cell Types ◽

Random Motion ◽

Chick Embryos ◽

Collision Efficiency ◽

20 Nm ◽

Kidney Liver ◽

Different Cell Types ◽

Laminar Shear ◽

Lyophobic Sols

Cell suspensions were prepared from the kidney, liver and heart of chick embryos of 5 or 8 days of incubation, and from the limb-buds of chick embryos of 5, 6, 7, 8 or 9 days of incubation. When these suspensions were aggregated under laminar shear in a Couette viscometer or random motion in a reciprocating shaker they obeyed the theoretical relationships derived for flocculating lyophobic sols. The values of the collision efficiency found for the different cell types under given conditions were used to calculate the force of interaction between cells of each type. The force of interaction ranged between 9 × 10−11 N (8-day heart) and 3 × 10−9 N (8-day liver). The forces of interaction between cells appear to be responsible for aligning the membranes of adjacent cells with a 10–20 nm gap. It is possible to arrange the cell types in a hierarchy based on the forces of interaction between them. The possible role of these forces in cell specificity is considered.

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Protective Role of Thyroxine in Methylparathion Intoxicated Chick Embryos

Drug and Chemical Toxicology ◽

10.3109/01480549809002218 ◽

1998 ◽

Vol 21 (4) ◽

pp. 495-506 ◽

Cited By ~ 1

Author(s):

Ghosh C. Bandyopadhyay ◽

S. Medda

Keyword(s):

Protective Role ◽

Chick Embryos

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The specification of noradrenergic locus coeruleus (LC) neurones depends on bone morphogenetic proteins (BMPs)

Development ◽

10.1242/dev.129.4.983 ◽

2002 ◽

Vol 129 (4) ◽

pp. 983-991 ◽

Cited By ~ 2

Author(s):

Astrid Vogel-Höpker ◽

Hermann Rohrer

Keyword(s):

Transcription Factors ◽

Locus Coeruleus ◽

Bone Morphogenetic Proteins ◽

Chick Embryos ◽

Dorsal Midline ◽

Neural Crest Development ◽

Roof Plate ◽

Rhombic Lip ◽

The Brain

The role of BMPs in the development of the major noradrenergic centre of the brain, the locus coeruleus (LC), was investigated. LC generation is reflected by initial expression of the transcription factors Phox2a and Phox2b in dorsal rhombomere1 (r1), followed by expression of dopamine-β-hydroxylase and tyrosine hydroxylase. Bmp5 is expressed in the dorsal neuroepithelium in proximity to Phox2-expressing cells. BMP inhibition in stage 10 chick embryos resulted in the lack of LC neurones or in their generation at the dorsal midline, and loss of roof plate and rhombic lip, but it did not affect neural crest development. These results reveal late essential BMP functions in the specification of dorsal neuronal phenotypes in r1, including LC neurones, and in the development of dorsal midline structures.

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Role of the chicken homeobox-containing genes GHox-4.6 and GHox-8 in the specification of positional identities during the development of normal and polydactylous chick limb buds

Development ◽

10.1242/dev.115.2.629 ◽

1992 ◽

Vol 115 (2) ◽

pp. 629-637 ◽

Cited By ~ 3

Author(s):

C.N. Coelho ◽

W.B. Upholt ◽

R.A. Kosher

Keyword(s):

Limb Development ◽

Ectopic Expression ◽

Limb Bud ◽

Chick Embryos ◽

Limb Buds ◽

Hox Gene ◽

Wing Bud ◽

Coated Bead ◽

Experimentally Induced

During early stages of normal chick limb development, the homeobox-containing (HOX) gene GHox-4.6 is expressed throughout the posterior mesoderm of the wing bud from which most of the skeletal elements including the digits will develop, whereas GHox-8 is expressed in the anterior limb bud mesoderm which will not give rise to skeletal elements. In the present study, we have examined the expression of GHox-4.6 and GHox-8 in the wing buds of two polydactylous mutant chick embryos, diplopodia-5 and talpid2, from which supernumerary digits develop from anterior limb mesoderm, and have also examined the expression of these genes in response to polarizing zone grafts and retinoic acid-coated bead implants which induce the formation of supernumerary digits from anterior limb mesoderm. We have found that the formation of supernumerary digits from the anterior mesoderm in mutant and experimentally induced polydactylous limb buds is preceded by the ectopic expression of GHox-4.6 in the anterior mesoderm and the coincident suppression of GHox-8 expression in the anterior mesoderm. These observations suggest that the anterior mesoderm of the polydactylous limb buds is “posteriorized” and support the suggestion that GHox-8 and GHox-4.6, respectively, are involved in specifying the anterior non-skeletal and posterior digit-forming regions of the limb bud. Although the anterior mesodermal domain of GHox-8 expression is severely impaired in the mutant and experimentally induced polydactylous limb buds, this gene is expressed by the prolonged, thickened apical ectodermal ridges of the polydactylous limb buds that extend along the distal anterior as well as the distal posterior mesoderm.(ABSTRACT TRUNCATED AT 250 WORDS)

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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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Rôle du mésoderme somitique dans le développement du plumage dorsal chez l'embryon de Poulet

Development ◽

10.1242/dev.28.2.343 ◽

1972 ◽

Vol 28 (2) ◽

pp. 343-366

Author(s):

Par Annick Mauger

Keyword(s):

Early Stage ◽

Cervical Region ◽

Lumbar Region ◽

Chick Embryos ◽

A Chain ◽

Normal Differentiation ◽

Time Of Operation ◽

Somitic Mesoderm ◽

Axial Organs

The role of somitic mesoderm in the development of dorsal plumage in chick embryos. II. Regionalisation. Transplantation and inversion experiments were performed on the somitic mesoderm of 2- to 2·5-day chick embryos in order to study the role of regional and axial determinations in the development of the dorsal plumage. The transposition of a piece of somitic mesoderm from the posterior cervical region (where the spinal pteryla is narrow) to the thoraco-lumbar region (where it is wide) leads to a local and unilateral narrowing of the spinal pteryla at the operation site. Conversely, the transposition of somitic mesoderm from the thoraco-lumbar region to the posterior cervical region results in a local and unilateral widening of the spinal pteryla. Consequently at the time of operation the segmented or not yet segmented somitic mesoderm is already determined to give rise to a definite transverse level of the spinal pteryla. The inversion of the cephalo-caudal polarity of a piece of somitic mesoderm without the ectodermal covering, or of a portion of the axial organs deprived of the overlying ectoderm has no effect on the orientation of feather filaments and feather rows. In contrast, the inversion of the cephalo-caudal polarity of a portion of the axial organs together with the overlying ectoderm results in the development of feathers growing in a cephalad direction and feather chevrons opening towards the head of the embryo. The inversion of the dorso-ventral polarity of a piece of somitic mesoderm does not prevent the normal differentiation of feathers in the operated region. The inversion of the medio-lateral polarity of a piece of unsegmented somitic mesoderm has little effect on the development of the spinal pteryla. On the contrary, the medio-lateral inversion of a chain of somites precludes the formation of the feathers at the level of operation. The somitic mesoderm, even when segmented, is endowed with extensive regulative capacity of its axes, except for the medio-lateral polarity, which is fixed irreversibly at the time of segmentation. The regional determination of the feather-forming somitic mesoderm is acquired at an early stage, at any rate before segmentation. However, at a given transverse level of the cephalo-caudal axis, the somitic cells remain totipotent as concerns their histo-genetic destiny (dermatome, myotome, or sclerotome) until after the onset of segmentation.

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The role of ultimobranchial bodies in the modulation of the response of chick embryos to 1,25-dihydroxycholecalciferol

Development ◽

10.1242/dev.97.1.87 ◽

1986 ◽

Vol 97 (1) ◽

pp. 87-94

Author(s):

Roberto Narbaitz ◽

Jaffar Soleimani Rad

Keyword(s):

Bone Resorption ◽

Ethyl Alcohol ◽

Inorganic Phosphate ◽

Histological Study ◽

Chorioallantoic Membrane ◽

Chick Embryos ◽

Series Of Experiments ◽

Ultrastructural Characteristics ◽

Bone Trabeculae

Ultimobranchial bodies (UBBs) were dissected from 17-day-old chick embryos and grafted onto the chorioallantoic membrane of 8-day-old embryos. The embryos with UBB grafts as well as sham-grafted controls were injected on the 10th day of incubation with 100 ng 1,25(OH)2D3 dissolved in ethyl alcohol or with an equal volume of ethyl alcohol alone; embryos were sacrificed on the 13th day. Grafted UBBs showed ultrastructural characteristics typical of actively secreting glands. A histological study of the tibiae from all embryos showed that while the grafted embryos responded to the injection of 1,25(OH)2D3 with a peripheral rim of undermineralized bone trabeculae, sham-grafted embryos never did so. These results confirm the original hypothesis that the presence of differentiated UBBs is a precondition for the production of undermineralized bone (osteoid) by 1,25(OH)2D3. In a second series of experiments, similarly treated embryos were sacrificed on the 10th, 11th, 12th and 13th day; the levels of calcium and inorganic phosphate were determined in their blood. The injection of 1,25(OH)2D3 produced in all embryos hypercalcaemia and hypophosphataemia. However, the hypophosphataemic response was more prolonged in the embryos with UBB grafts than in sham-grafted ones. These results suggest that the grafted UBBs prolonged the hypophosphataemic response, probably by secreting calcitonin and thus reducing the rate of bone resorption. It is also probable that the prolonged hypophosphataemia produced or contributed to the undermineralization of the peripheral (subperiosteal) trabeculae.

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