Induction of the primitive streak in the chick blastoderm embryo: patterns of protein synthesis

1986 ◽  
Vol 195 (1) ◽  
pp. 80-83 ◽  
Author(s):  
Nikolas Zagris ◽  
Demetrios Matthopoulos
Development ◽  
1964 ◽  
Vol 12 (4) ◽  
pp. 609-619
Author(s):  
Anna Hell

Enormous progress has been made in the last few years towards the elucidation of the mechanism of protein synthesis, and great interest is centred on the steps leading to cellular differentiation and specific protein synthesis. We know that genetic information is passed on from one generation of cells to the next by deoxyribonucleic acid (DNA), and that this material directs all protein synthesis by the intermediary of the different types of ribonucleic acid (RNA). A simple in vitro system described by O'Brien (1959) seemed to offer an excellent tool for the study of the differentiation of the blood islands, and the initial formation of a well-known protein, haemoglobin (Hb), in chick embryonic tissues. After de-embryonation, chick blastoderms, from the stage of primitive streak onwards, can be cultured in vitro on a saline agar medium supplemented with glucose.


Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 445-459
Author(s):  
B. Levak-Švajger ◽  
A. Švajger

Single germ layers (or combinations of two of them) were isolated from the primitive streak and the head-fold stage rat embryos and grown for 15 days under the kidney capsule of syngeneic adult animals. The resulting teratomas were examined histologically for the presence of mature tissues, with special emphasis on derivatives of the primitive gut. Ectoderm isolated together with the initial mesodermal wings at the primitive streak stage gave rise to tissue derivatives of all three definitive germ layers. Derivatives of the primitive gut were regularly present in these grafts. At the head-fold stage, isolated ectoderm (including the region of the primitive streak) differentiated into ectodermal and mesodermal derivatives only. Endoderm isolated at the primitive streak stage did not develop when grafted and was always completely resorbed. At the head-fold stage, however, definitive endoderm differentiated into derivatives of the primitive gut if grafted together with adjacent mesoderm. These findings indirectly suggest the migration of prospective endodermal cells from the primitive ectoderm, and therefore a general analogy with the course of events during gastrulation in the chick blastoderm.


1980 ◽  
Vol 160 (3) ◽  
pp. 361-367 ◽  
Author(s):  
Ch. Vanroelen ◽  
L. Vakaet ◽  
L. Andries

1975 ◽  
Vol 45 (2) ◽  
pp. 358-365 ◽  
Author(s):  
Hefzibah Eyal-Giladi ◽  
Isaac Farbiasz ◽  
David Ostrovsky ◽  
Jacob Hochman

1934 ◽  
Vol 11 (3) ◽  
pp. 218-223
Author(s):  
C. H. WADDINGTON

1. Two cases of induction by coagulated organisers in the chick are described. The implants consisted of pieces of chick primitive streak, and previous to implantation they were killed and coagulated by immersion in boiling water. After this treatment they still retained the inducing capacity which they have been previously shown to possess in the live state. 2. Grafts of dead material into the chick blastoderm usually become enveloped in mesenchyme and thus isolated from the host ectoderm. 3. It is argued that, although there may in the normal egg be a gradient of inducing capacity, the inducing factor itself cannot be a gradient as such: and reference is made to the most recent work which shows that the factor is actually a chemical substance. 4. It is pointed out that there is as yet no evidence that dead organisers can determine the regional character of the embryonic axes which they induce, as live organisers can. 5. In one of the specimens described, the induced axis is accompanied by induced notochord. The question is raised as to whether this notochord is the direct result of the inducing stimulus acting on the host ectoderm, or whether the influence of the host's individuation field has played a part in its formation.


Development ◽  
1980 ◽  
Vol 58 (1) ◽  
pp. 209-216
Author(s):  
Nikolas Zagris

Morphologically distinct erythroid cell types characteristic of the primitive and the definitiveerythroid cell lines, and embryonic and adult haemoglobins are produced when the unin-cubated chick blastoderm is cultured ventral side down on a filter raft to inhibit morphogeneticmovements and subsequent primitive-streak formation mechanically in serum-free minimalessential medium. The primitive and definitive erythroid cell populations appear consecutivelyin culture even though there is no axis formation nor apparent morphogenesis. The informa-tion to produce both the early and late haemoglobins and erythroid cell types is independentof axis formation and of specific extra-embryonic influences, such as progressive inductionexerted by the yolk mass.


Development ◽  
1958 ◽  
Vol 6 (1) ◽  
pp. 149-161
Author(s):  
Ruth Bellairs

In almost all embryos yolk becomes converted into cytoplasm. It has not previously been possible to describe in any detail the morphological changes involved in this process; indeed, when the yolk drops contained within embryonic cells are examined by light microscopy they seem to remain in much the same condition until they are suddenly used up. For this reason they have frequently been considered to be nothing but ‘inert, inactive’ stores of food. By using an electron microscope, however, it has been possible to trace some of the morphological changes which take place in the chick when intra-cellular yolk drops are converted into cytoplasm, and to show that these are not confined to a single stage of embryonic development. Moreover, the discovery of mitochondria within the yolk drops suggests that the yolk drops are not ‘inert’. The following stages have been examined: medium and long primitive streak (as defined by Waddington, 1932, and Abercrombie, 1950), head process, head fold, and 10–16 pairs of somites.


Development ◽  
1988 ◽  
Vol 104 (4) ◽  
pp. 643-655 ◽  
Author(s):  
D.R. Canning ◽  
C.D. Stern

We report that a monoclonal antibody, HNK-1, identifies specific regions and cell types during primitive streak formation in the chick blastoderm. Immunohistochemical studies show that the cells of the forming hypoblast are HNK-1 positive from the earliest time at which they can be identified. Some cells of the margin of the blastoderm are also positive. The mesoderm cells of the primitive streak stain strongly with the antibody from the time of their initial appearance. In the epiblast, some cells are positive and some negative at pre-primitive-streak stages, but as the primitive streak develops a gradient of staining intensity is seen within the upper layer, increasing towards the primitive streak. At later stages of development, the notochord and the mesenchyme of the headfold are positive, while the rest of the mesoderm (lateral plate) no longer expresses HNK-1 immunoreactivity. This antibody therefore reveals changes associated with mesodermal induction: before induction, it recognizes the ‘inducing’ tissue (the hypoblast) and reveals a mosaic pattern in the responding tissue (the epiblast); after primitive streak formation, the mesoderm of the primitive streak that results from the inductive interactions expresses the epitope strongly. Affinity purification of HNK-1-related proteins in various tissues was carried out, followed by SDS-PAGE to identify them. The hypoblast, mesoderm and epiblast of gastrulating chick embryos have some HNK-1-related proteins in common, while others are unique to specific tissues. Attempts have been made to identify these proteins using Western blots and antibodies known to recognize HNK-1-related molecules, but none of the antibodies used identify the bands unique to any of the tissues studied. We conclude that these proteins may be novel members of the HNK-1/L2 family, and that they may have a role in cell interactions during early development.


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