Etude autoradiographique des premiers stades du développement de l'ébauche du membre antérieur chez deux espèces de Chéloniens (Testudo graeca L. et Emys orbicularis L.)

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 585-600
Author(s):  
Par J. Vasse
Keyword(s):  
Tritiated Thymidine ◽  
Flank Region ◽  
Autoradiographic Study ◽  
Labelling Index ◽  
Limb Bud ◽  
Chick Embryos ◽  
Emys Orbicularis ◽  
Testudo Graeca ◽  
Histological Sections

Autoradiographic study of early stages of the anterior limb-bud in two species of chelonian embryos Embryos of two chelonian species (Testudo graeca L., Emys orbicularis L.) from 20-somites stage to 34-somites stage, fixed 2–4 h after an injection of tritiated thymidine or uridine or leucine, then emulsion-exposed 12–14 days, showed the following results: (1) When the labelling index was determined in the mesoderm of the somatopleure, the labelling index in the flank region (S13–S16) remained at about 0·3 but the labelling index in the prospective anterior limb region rose to 0·4–0·5 when the processes of the somites S6–S13 reached the somatopleure. The somites seem to induce the proliferation of the somatopleure and the transformation of the somatopleural cells in mesoblastic basophilic cells. (2) The dilated extremities of the processes of somites S6–S12 proliferate cells which become free from the somite and multiply. Thus, the somites S6–S12 participate materially in the constitution of the mesoblastic blastema of the limb-bud. (3) In the mesoblast, regionalizations appear in transverse histological sections – in the cranial-caudal direction. (4) An apical epiblastic crest develops, at 26–27-somites stage, in the area where the mesoblastic cells are the most abundant and the most active (between somites S8 and S11). At 28–29-somites stage, this crest Anlage synthesizes very little DNA; and at 34-somites stage the synthesis of RNA and proteins also decreases. These results are compared with results obtained in other reptiles and chick embryos, in the light of the theories on the role of the somites and of the apical crest in the development of the anterior limb-bud.

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 ◽  
1992 ◽  
Vol 115 (2) ◽  
pp. 629-637 ◽  
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)

Etudes expérimentales sur le rôle des somites au cours des premiers stades du développement du membre antérieur chez l'embryon du Chélonien Emys orbicularis L.

Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 417-430
Author(s):  
Par J. Vasse
Keyword(s):  
Experimental Study ◽  
Developmental Stage ◽  
Limb Development ◽  
Limb Bud ◽  
Stages Of Development ◽  
Emys Orbicularis ◽  
Bud Development ◽  
Early Stages

Experimental study on the role of the somites during the early stages of development of the front limbs of the embryo of the chelonian Emys orbicularis L. Ablation of postotic somites 6–13 on one side in embryos of Emys orbicularis L. at the developmental stage when 20–23 somite pairs were present, led to arrest of forelimb-bud development in the somatopleure adjacent to the ablated somites on the operated side. Limb development in the somatopleure adjacent to intact somites on the operated side was unaffected, attaining the same stage as on the non-operated side. Ablation at later stages (25–33 somite pairs) did not prevent development of the limb adjacent to the ablated somites. When a part of the prospective somatopleure was injured, the remaining part formed a small limb-bud. When an obstacle was placed between the somatopleural mesoderm and the adjacent somite, development of the somatopleure stopped at this level. These results corroborate those obtained from previous studies in various reptilian embryos concerning the role of the ventral somite extensions as activators of proliferation in the somatopleural mesoderm. Injury to the ventral extension alone led to serious disturbances in the somatopleural mesoderm adjacent to this somite.

scholarly journals Further evidence in support of cell-surface-associated deoxyribonucleic acid in tumor cells: an autoradiographic study.

1977 ◽  
Vol 25 (5) ◽  
pp. 359-370 ◽  
Author(s):  
S K Aggarwal
Keyword(s):  
Plasma Membrane ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Membrane Surface ◽  
Autoradiographic Study ◽  
Sarcoma 180 ◽  
Grain Distribution ◽  
Tumor Implant ◽  
Plasma Membrane Surface

Ascites sarcoma-180 cells, when stained with platinum-pyrimidine complexes as the sole electron dense stain, show distinct dense patches to granular appearance on the surface of the plasma membrane which has been suggested to be attributable to deoxyribonucleic acid. Swiss Webster mice, 4-5 weeks of age, weighing 24-26 g with 4 X 10(6) ascites sarcoma-180 cells when injected with 3 X 7.0 micronC of tritiated thymidine on day 5 of the tumor implant, show specific labeling on the plasma membrane surface. The photopositive silver grain distribution in both the light and electron microscope autoradiograms when followed from the nucleus outwards show a distinct peak over the nucleus and the plasma membrane. The quantity and origin and role of this surface-associated deoxyribonucleic acid is not clear.

Cell proliferation in condensing scleral ectomesenchyme associated with the conjunctival papillae in the chick embryo

Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 25-37
Author(s):  
Maarten Van De Kamp ◽  
S. Robert Hilfer
Keyword(s):  
Cell Proliferation ◽  
Chick Embryo ◽  
Tritiated Thymidine ◽  
Chick Embryos ◽  
Short Term ◽  
Thymidine Labelling ◽  
Conjunctival Papillae

The role of cell proliferation in the formation of scleral ectomesenchymal condensations underlying the conjunctival papillae was examined with in vivo tritiated thymidine labelling in chick embryos ranging in age from 8 days 0 h to 10 days 12 h. Percentages of labelled nuclei were determined in both ectomesenchyme and the deeper fibrous sclera for short-term and continuous tritiated thymidine incubations. During formation of the ectomesenchymal condensations the percentages of labelled nuclei were consistently higher within the condensations than in corresponding non-condensing ectomesenchyme between papillae. The consistent differences of labelling percentages observed within the condensing versus noncondensing ectomesenchyme were not found in the fibrous sclera at any stage. All areas of both the ectomesenchyme and fibrous sclera showed decreases in the percentages of labelled nuclei from 8 days Oh to 10 days 12h, although the decline in the ectomesenchymal condensations beneath papillae occurred more slowly than in areas between papillae. The data suggest that the conjunctival papillae directly influence the proliferation in the subjacent condensing ectomesenchyme but have no effect on the ectomesenchyme between papillae or any region of the deeper fibrous sclera. The observations of this investigation are discussed in relation to other studies of the development of the pre-ossicular mesenchyme.

Notochord to endoderm signaling is required for pancreas development

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4243-4252 ◽  
Author(s):  
S.K. Kim ◽  
M. Hebrok ◽  
D.A. Melton
Keyword(s):  
Gene Expression ◽  
Developmental Stage ◽  
Pancreas Development ◽  
Chick Embryos ◽  
Carboxypeptidase A ◽  
Bud Development ◽  
Dorsal Pancreas ◽  
Stepwise Manner

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.

The development of the tectum in Xenopus laevis: an autoradiographic study

Development ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 87-115
Author(s):  
K. Straznicky ◽  
R. M. Gaze
Keyword(s):  
Xenopus Laevis ◽  
Dna Synthesis ◽  
Optic Tectum ◽  
Tritiated Thymidine ◽  
Dorsal Surface ◽  
Autoradiographic Study ◽  
Cell Type ◽  
Pole Cells ◽  
Serial Addition ◽  
The Times

The development of the optic tectum in Xenopus laevis has been studied by the use of autoradiography with tritiated thymidine. The first part of the adult tectum to form is the rostroventral pole; cells in this position undergo their final DNA synthesis between stages 35 and 45 or shortly thereafter. Next, the cells comprising the ventrolateral border of the tectum form. These cells undergo their final DNA synthesis at or shortly after stage 45. Finally the cells comprising the dorsal surface of the adult tectum form, mainly between stages 50–55. This part of the tectum originates from the serial addition of strips of cells medially, which displace the pre-existing tissue laterally and rostrally. The formation of the tectum is virtually complete by stage 58. The tectum in Xenopus thus forms in topographical order from rostroventral to caudo-medial. The distribution of labelled cells, several stages after the time of injection of isotope, indicates that, at any one time, a segment of tectum is forming which runs normal to the tectal surface and includes all layers from the ventricular layer out to the surface. In Xenopus, therefore, the times of origin of tectal cells appear to be related not to cell type or tectal layer but to the topographical position of the cells across the surface of the tectum.

Expression of serologically detectable H-2 antigens on mid-gestation mouse embryonic tissues

Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 207-219
Author(s):  
Katrina J. Kirkwood ◽  
W. D. Billington
Keyword(s):  
Antigen Expression ◽  
Limb Bud ◽  
Major Histocompatibility ◽  
Embryonic Tissues ◽  
Histocompatibility Complex ◽  
Cellular Recognition ◽  
Major Histocompatibility Antigens ◽  
Embryonic Skin ◽  
Specific Haplotype

Mixed haemadsorption assays using antibody-coaled indicator sheep erythrocytes and mouse alloantisera revealed that major histocompatibility complex (H-2) antigens were expressed on cells of 24–72 h cultures of mid-gestation mouse embryonic skin, gut, lung, limb-bud and heart but not of embryonic gonad or kidney. The precise time of detection of H-2 antigen expression and the proportions of cells expressing these determinants depended on inbred strain, specific haplotype, tissue of origin and antiserum batch employed. In all tissues the proportion of cells expressing H-2 increased progressively from day 11–12 postcoitum onwards. The findings are discussed with respect to hypotheses concerning the possible role of major histocompatibility antigens in cellular recognition and interactions during embryogenesis.

Measurements of cell adhesion

Development ◽  
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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