The origin and movement of nephrogenic cells in the chick embryo as determined by radioautographic mapping

Development ◽  
1970 ◽  
Vol 24 (2) ◽  
pp. 367-380
Author(s):  
Glenn C. Rosenquist

The origin of the presumptive nephrogenic cells in the epiblast of the chick embryo was traced by radioautographic analysis of the movements of tritiated thymidine-labelled grafts excised from medium-streak to 5-somite stage embryos and transplanted to epiblast, streak, and the endoderm-mesoderm layer of similarly staged recipient embryos. The nephrogenic cells originate near the area pellucida margin of the medium-streak-stage embryo, migrate toward the streak, and are invaginated about one-third to one-half the distance from the anterior to the posterior end of the streak, between the definitive-streak and I - to 4-somite stages. Their route into mesoderm is along a relatively narrow pathway between the cells migrating to the paraxial or presomite mesoderm on one side, and those destined for the proximal limbs of the lateral plate on the other. The cells which will form the anterior part of the intermediate mesoderm are the most medially placed cells in epiblast, reach the streak at an earlier stage of development, and are the first nephrogenic cells to migrate into mesoderm. After about the 17– to 19-somite stage, cells from this group which have formed the pronephric cord or duct begin to move posteriorly in relation to the rest of the intermediate mesoderm, toward the future cloaca. The last nephrogenic cells to leave epiblast and enter the streak and mesoderm are those destined for the posterior end of the intermediate mesoderm. This group of cells surrounds the posteriorly migrating pronephric (Wolffian) duct and differentiates into mesonephros.

Development ◽  
1968 ◽  
Vol 20 (3) ◽  
pp. 247-260
Author(s):  
Teresa Rogulska

Suggestive evidence for the extragonadal origin of germ cells in birds was first presented by Swift (1914), who described primordial germ cells in the chick embryo at as early a stage as the primitive streak. According to Swift, primordial germ cells are originally located extra-embryonically in the anterior part of the blastoderm and occupy a crescent-shaped region (‘germinal crescent’) on the boundary between area opaca and area pellucida. Swift also found that primordial germ cells later enter into the blood vessels, circulate together with the blood throughout the whole blastoderm and finally penetrate into the genital ridges, where they become definitive germ cells. Swift's views have been confirmed in numerous descriptive and experimental investigations. Among the latter, the publications of Willier (1937), Simon (1960) and Dubois (1964a, b, 1965a, b, 1966) merit special attention. Dubois finally proved that the genital ridges exert a strong chemotactic influence on the primordial germ cells.


Development ◽  
1992 ◽  
Vol 114 (4) ◽  
pp. 841-852 ◽  
Author(s):  
O. Sundin ◽  
G. Eichele

Chick Ghox 2.9 protein, a homeodomain-containing polypeptide, is first detected in the mid-gastrula stage embryo and its levels increase rapidly in the late gastrula. At this time, the initially narrow band of expression along the primitive streak expands laterally to form a shield-like domain that encompasses almost the entire posterior region of the embryo and extends anteriorly as far as Hensen's node. We have found that this expression domain co-localizes with a morphological feature that consists of a stratum of refractile, thickened mesoderm. Antibody-staining indicates that Ghox 2.9 protein is present in all cells of this mesodermal region. In contrast, expression within the ectoderm overlying the region of refractile mesoderm varies considerably. The highest levels of expression are found in ectoderm near the streak and surrounding Hensen's node, regions that recent fate mapping studies suggest that primarily destined to give rise to neurectoderm. At the definitive streak stage (Hamburger and Hamilton stage 4) the chick embryo is especially sensitive to the induction of axial malformations by retinoic acid. Four hours after the treatment of definitive streak embryos with a pulse of retinoic acid the expression of Ghox 2.9 protein is greatly elevated. This ectopic expression occurs in tissues anterior to Hensen's node, including floor plate, notochord, presumptive neural plate and lateral plate mesoderm, but does not occur in the anteriormost region of the embryo. The ectopic induction of Ghox 2.9 is strongest in ectoderm, and weaker in the underlying mesoderm. Endoderm throughout the embryo is unresponsive. At stage 11, Ghox 2.9 is normally expressed at high levels within rhombomere 4 of the developing hindbrain. In retinoic-acid-treated embryos which have developed to this stage, typical rhombomere boundaries are largely absent. Nevertheless, Ghox 2.9 is still expressed as a discrete band, but one that is widened and displaced to a more anterior position.


Author(s):  
Margaret H. Sanderson ◽  
S. Phyllis Steamer

The chick embryo exposed to lethal doses of ionizing radiations develops a fatal circulatory failure within a few hours. This report describes the blood vessels of the area pellucida (a part of the extra-embryonic membranes of the chick embryo) and the effect of 250 kVp x-radiation upon them.Three-day chick embryos, x-irradiated in ovo with 1000-1200 R, were fixed 1-2 hours after exposure. The area pellucida is a multi-layered membrane consisting of ectoderm, somatic and splanchnic mesoderm, and endoderm (Fig. 1). The vascular system arises from the splanchnic mesoderm. The walls of small and medium-sized vessels are composed of endothelial cells, an occasional pericyte and processes of adjacent mesenchyme cells. Types of vessels cannot be distinguished at this stage of development; a basement membrane is seen only in isolated areas. The wall appears double or triple-layered, but the endothelium is frequently less than 0.1 micron thick (Fig. 2). Endothelial cells contain a large complement of polyribosomes, mitochondria, rough and smooth endoplasmic reticulum, a Golgi complex, pinocytotic vesicles and several kinds of inclusion bodies. The nucleus has a well-defined nucleolus.


Experiments previously reported (Needham, 1932, a, b, c ) have thrown some light on the metabolism of the chick embryo and its accessory structures by manometric determinations of respiratory quotient. These determinations, however, were confined to the blastoderm ( area opaca and area pellucida ) up to the 60th hour of incubation, of the embryo up to the 6th day, and of the yolk-sac between 2½ and 7 days of development. In order to complete the picture, it was necessary to carry out similar determinations on the yolk-sac during the remainder of development and on the allantois, from its first appearance before the 5th day to the time of hatching. These form the subject of the present paper. The extra embryonic membranes of the later stages of development are in some respects easier to deal with than those of the first week. But although they become less fragile they also become more heterogeneous, until at last it may be difficult, if not impossible, to select any portion of the yolk-sac, for example, which shall be representative of the system as a whole. This difficulty will be referred to below. On the other hand, the value of the membranes as sheets of living cells which can be studied manometrically without even the minor degree of traumatism involved in the cutting of razor-slices, should not be underestimated.


Development ◽  
1970 ◽  
Vol 24 (3) ◽  
pp. 497-509
Author(s):  
Glenn C. Rosenquist

The origin of the prelung cells was determined by tracing the movements of [3H]thymidinelabelled grafts excised from medium-streak to 4-somite stage chick embryos and transplanted to the epiblast, streak, and endoderm-mesoderm of similarly staged recipient embryos. At the medium-streak stage the prelung endoderm cells are in the anterior third of the primitive streak; they shortly begin to migrate anteriorly and laterally into the endoderm layer. They are folded into the gut beginning at about the 4-somite stage, and begin to reach their definitive position in the ventrolateral gut wall at the 10- to 16-somite stage. At the ± 22-somite stage the prelung endoderm begins to burrow into the overlying splanchnic layer of mesoderm, pushing the prelung mesoderm ahead of it. At the medium-streak stage the prelung mesoderm is in the epiblast (dorsal) layer about half-way to the lateral margin of the area pellucida on either side of the streak, at a level about half-way between the anterior and posterior ends of the streak. From this position the prelung mesoderm migrates medially to the streak and is invaginated into the mesoderm layer at a position about half-way between the anterior and posterior ends of the streak. As a section of the dorsal mesentery, it migrates anteriorly and laterally from the streak into the splanchnic mesoderm lateral to the somites. From the head process stage to the early somite stages, the prelung mesoderm is located posterior to the prelung endoderm. The prelung mesoderm continues to migrate with the splanchnic mesoderm into the mesentery dorsal to the heart, where it invests the prelung endoderm after the 16- to 19-somite stage. Beginning at about the 22-somite stage, the prelung endoderm penetrates the prelung mesoderm and the bilateral bronchi are formed.


Development ◽  
1971 ◽  
Vol 25 (1) ◽  
pp. 97-113
Author(s):  
Glenn C. Rosenquist

The origin of the prehepatic cells was determined by tracing the movements of [3H]thymidine-labelled grafts excised from medium-streak to 4-somite stage chick embryos and transplanted to the epiblast, streak and endoderm-mesoderm layer of similarly staged recipient embryos. Although exact definition of prehepatic areas was not possible because of the small number of grafts placed at each developmental stage, the study showed in general that at the medium-streak stage, the prehepatic endoderm cells are in the anterior third of the primitive streak; they shortly begin to migrate anteriorly and laterally into the endoderm layer ventral to the precardiac areas of mesoderm. They are in the yolk-sac endoderm at the 2–4-somite stage, and by the 15–17-somite stage are clustered at the anterior intestinal portal. At the 26-somite to early limb-bud stages, the anterior and posterior liver diverticula have formed from these endoderm cells, and some of the branches of the diverticula may have reached the prehepatic mesenchyme, where the two tissues have begun to form cords and sinuses. At the medium-streak stage, the prehepatic mesoderm is located slightly more than halfway from the anterior to the posterior end of the primitive streak. From this position it migrates anteriorly and laterally into the lateral plate mesoderm, and from the head-process to the 2–4-somite stage it is situated posterior to the prehepatic endoderm and posterior and lateral to the heart-forming portion of the splanchnic layer. By the 15–17-somite stage the prehepatic mesoderm has reached a position in the splanchnic layer of mesoderm which forms the dorsolateral wall of the sinus venosus. By the 26-somite to early limb-bud stage the hepatic diverticula have joined with the hepatic mesenchyme to form the rudimentary cords and sinuses of the liver.


Development ◽  
1985 ◽  
Vol 85 (1) ◽  
pp. 65-80
Author(s):  
Robin H. Lovell-Badge ◽  
Martin J. Evans ◽  
Ruth Bellairs

Tissues dissected from early chick embryos were labelled in vitro with [35S]methionine, and their patterns of polypeptide synthesis investigated using the technique of two-dimensional (2–D) polyacrylamide gel electrophoresis. Apart from providing a preliminary description of the molecular changes associated with the processes of gastrulation and segmentation in the chick embryo, this study has revealed a number of polypeptides that may be useful as markers of cell type or function. The protein synthetic patterns of hypoblast from early and late gastrulae (stages 2 and 4, respectively: Hamburger & Hamilton, 1951) and of definitive endoblast and junctional endoblast from late gastrulae all resemble one another closely, but differ markedly from that of the epiblast at either stage. The lower layer tissues are characterized by the presence of eleven polypeptides that are largely absent from the epiblast. These findings are discussed with reference to current theories on the origins of the lower layer tissues. Comparisons between the 2-D patterns for tissues dissected from gastrulae and from embryos undergoing segmentation (stage 12) have revealed ten polypeptides showing stage-specific rather than tissue-specific expression. Apart from these ten polypeptides, the 2–D patterns for epiblast and ectoderm were practically identical, and distinguishable from those of other tissues by a lack of any unique polypeptides. On the other hand, stage-4 endoblast and stage-12 endoderm differed in the expression of many polypeptides. One polypeptide was found that may be considered as a marker of mesodermal cell type, as it was present in lateral plate, segmental plate and somitic mesoderm, but not in tissues of the other germ layers. Lateral plate could be distinguished from the other mesodermal tissues in the expression of a number of polypeptides, but the similarity in the 2–D patterns for segmental plate and somites suggest that the separation of somites from the anterior end of the segmental plate is not accompanied by the synthesis of new polypeptides.


1972 ◽  
Vol 50 (11) ◽  
pp. 1242-1244 ◽  
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright ◽  
I. H. Fraser

Chloramphenicol markedly inhibited the formation of hemoglobin by chick blastodiscs explanted before the 8-somite stage of development onto minimal or egg homogenate medium. Sensitivity to inhibition of hemoglobin formation was reduced at the 8-somite stage. Chloramphenicol had no effect upon the incorporation of leucine into total protein, and only slightly inhibited the cycloheximide-resistant incorporation of leucine.


Author(s):  
Menghan TAO ◽  
Ning XIAO ◽  
Xingfu ZHAO ◽  
Wenbin LIU

New energy vehicles(NEV) as a new thing for sustainable development, in China, on the one hand has faced the rapid expansion of the market; the other hand, for the new NEV users, the current NEVs cannot keep up with the degree of innovation. This paper demonstrates the reasons for the existence of this systematic challenge, and puts forward the method of UX research which is different from the traditional petrol vehicles research in the early stage of development, which studies from the user's essence level, to form the innovative product programs which meet the needs of users and being real attractive.


1983 ◽  
Vol 218 (1210) ◽  
pp. 95-110 ◽  

(i) Following previous work on the morphological and physiological properties of the two distal joints (J2, J3) of the atenna of the rock lobster Palinurus vulgaris , the mechanical, muscular and proprioceptive organization of the two proximal joints between the antennal segments S1 and S2 (J1) and between S1 and the cephalothorax (J0) have now been studied. (ii) Articulated by two classical condyles, J1 moves in a mediolateral plane. One external rotator muscle (ER) and three internal rotator muscles (IR1, IR2, IR3) subserve its movements. J0 is articulated by two different systems: a classical ventrolateral condyle and a complex sliding system constituted by special cuticular structures on the dorsomedial side of the S1 segment and on the rostrum between the two antennae. J0 moves in the dorsoventral plane by means of a levator muscle (Lm) and a depressor muscle (Dm). A third muscle, the lateral tractor muscle (LTm), associated with J0 and lying obliquely across S1, may modulate the level of friction between the S1 segment and the rostrum. (iii) Proprioception in J1 is achieved by a muscle receptor organ AMCO-J1 (antennal myochordotonal organ for the J1 joint) associating a small accessory muscle (S1.am) located in the proximal part of the S1 segment and a chordotonal organ inserted proximally on the S1.am muscle and distally on the S2 segment. J0 proprioception is ensured by a simple chordotonal organ (CO-J0) located in the anterior part of the cephalothorax. (iv) The S1.am muscle is innervated by three motoneurons characterized by their very small diameters and inducing respectively tonic excitatory postsynaptic potentials, phasic excitatory postsynaptic potentials and inhibitory postsynaptic potentials. Anatomical and physiological observations suggest functional correlation between S1.am and IR1 motor innervation. (v) Mechanical and muscular organization of J0 and J1 are compared with that of the other joints of the antenna. The properties of the AMCO-J1 proprioceptor are discussed in relation to the other muscle receptor organs described in crustaceans.


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