Regional developmental capacities of the rat embryonic endoderm at the head-fold stage

A. Švajger; B. Levak-Švajger

doi:10.1242/dev.32.2.461

Regional developmental capacities of the rat embryonic endoderm at the head-fold stage

Development ◽

10.1242/dev.32.2.461 ◽

1974 ◽

Vol 32 (2) ◽

pp. 461-467

Author(s):

A. Švajger ◽

B. Levak-Švajger

Keyword(s):

Adult Male ◽

Primitive Streak ◽

Neural Plate ◽

Male Rats ◽

Germ Layers ◽

Kidney Capsule ◽

Gut Endoderm ◽

Derivatives Of

Three areas, composed of all three germ layers, were isolated from Fischer strain rat embryonic shields at the head-fold stage, and grafted separately under the kidney capsule of adult male rats of the same strain. The areas were from the neural plate, Hensen's node and the primitive streak. The resulting teratomas were examined histologically for the presence of derivatives of the primitive gut. The grafts differed strikingly in their capacity to develop into different segments of the gut. Endoderm underlying the neural plate developed into derivatives of the foregut, while endoderm underlying the primitive streak developed mainly into derivatives of the mid- and hindgut. It was concluded that, at the head-fold stage, the capacities to develop into different segments of the definitive gut are already roughly limited to particular areas of the endoderm.

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Investigation on the origin of the definitive endoderm in the rat embryo

Development ◽

10.1242/dev.32.2.445 ◽

1974 ◽

Vol 32 (2) ◽

pp. 445-459

Author(s):

B. Levak-Švajger ◽

A. Švajger

Keyword(s):

Primitive Streak ◽

Definitive Endoderm ◽

Rat Embryo ◽

Chick Blastoderm ◽

Germ Layers ◽

Kidney Capsule ◽

Rat Embryos ◽

Endodermal Cells ◽

Derivatives Of

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.

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The marginal zone and its contribution to the hypoblast and primitive streak of the chick embryo

Development ◽

10.1242/dev.109.3.667 ◽

1990 ◽

Vol 109 (3) ◽

pp. 667-682 ◽

Cited By ~ 17

Author(s):

C.D. Stern

Keyword(s):

Chick Embryo ◽

Marginal Zone ◽

Primitive Streak ◽

Time Lapse ◽

Study Time ◽

Fate Mapping ◽

Deep Part ◽

Germ Layers ◽

Gut Endoderm ◽

Transplantation Experiments

The marginal zone of the chick embryo has been shown to play an important role in the formation of the hypoblast and of the primitive streak. In this study, time-lapse filming, fate mapping, ablation and transplantation experiments were combined to study its contribution to these structures. It was found that the deep (endodermal) portion of the posterior marginal zone contributes to the hypoblast and to the junctional endoblast, while the epiblast portion of the same region contributes to the epiblast of the primitive streak and to the definitive (gut) endoderm derived from it. Within the deep part of the posterior marginal zone, a subpopulation of HNK-1-positive cells contributes to the hypoblast. Removal of the deep part of the marginal zone prevents regeneration of the hypoblast but not the formation of a primitive streak. Removal of both layers of the marginal zone leads to a primitive streak of abnormal morphology but mesendodermal cells nevertheless differentiate. These results show that the two main properties of the posterior marginal zone (contributing to the hypoblast and controlling the site of primitive streak formation) are separable, and reside in different germ layers. This conclusion does not support the idea that the influence of the posterior marginal zone on the development of axial structures is due to it being the source of secondary hypoblast cells.

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The histogenetic capacity of tissues in the caudal end of the embryonic axis of the mouse

Development ◽

10.1242/dev.82.1.253 ◽

1984 ◽

Vol 82 (1) ◽

pp. 253-266

Author(s):

P. P. L. Tam

Keyword(s):

Developmental Stages ◽

Primitive Streak ◽

Mouse Embryos ◽

Embryonic Axis ◽

Tail Bud ◽

Germ Layers ◽

Kidney Capsule ◽

Caudal Region ◽

Caudal Portion ◽

Adult Body

The caudal end of the embryonic axis consists of the primitive streak and the tail bud. Small fragments of this caudal tissue were transplanted from mouse embryos of various developmental stages to the kidney capsule in order to test their histogenetic capacity. The variety of mature tissues obtained from these small fragments was similar to that obtained by grafting a larger caudal portion of the embryo. Initially, the grafted tissue broke up into loose masses of embryonic mesenchyme and this was later re-organized into more compact tissues and into cysts that were lined with various types of epithelia. After 14 days in the ectopic site, grafted tissues coming from embryos of the primitive-streak, the early-somite and the forelimb-bud stages differentiated into structures that has presumably originated from the three embryonic germ layers. Many of these structures were related to the caudal region of the adult body, such as the mid- and hindgut segments and urogenital derivatives. The histogenetic capacity for endodermal tissues and urogenital organs was lost when the grafted tissue consisted entirely of the tail bud of the hindlimb-bud-stage embryos. The behaviour of the caudal tissues suggested that (1) the primordia for the various parts of embryonic body were derived from a small progenitor population in the primitive streak and the tail bud, and (2) the histogenetic capacity of this population changed during development.

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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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Metabolism of a glutathione conjugate of 2-hydroxyoestradiol-17β in the adult male rat

Biochemical Journal ◽

10.1042/bj1261067 ◽

1972 ◽

Vol 126 (5) ◽

pp. 1067-1071 ◽

Cited By ~ 18

Author(s):

John S. Elce

Keyword(s):

Bile Duct ◽

Adult Male ◽

Analytical Techniques ◽

Male Rats ◽

Male Rat ◽

Glutathione Conjugate ◽

Before And After ◽

Adult Male Rat ◽

Derivatives Of

Adult male rats with cannulated or ligated bile ducts were given S-(2-hydroxyoestradiol-1-yl)[35S]glutathione, S-(2-hydroxy[6,7-3H2]oestradiol-1-yl)glutathione or S-(2-hydroxyoestradiol-1-yl)[glycine-3H]glutathione by intraperitoneal injection. The recovery of radioactivity in the bile of bile duct-cannulated rats was 33–86% and in the urine of bile duct-ligated rats was 54–105%. Oestrogen thioether derivatives of glutathione, cysteinylglycine, cysteine and N-acetylcysteine were isolated from bile; only the N-acetylcysteine derivatives could be identified in the urine. The steroid moiety was characterized by microchemical tests before and after treatment with Raney nickel: 2-hydroxyoestradiol-17β was released from the glutathione conjugate, and 2-hydroxyoestrone and 2-hydroxyoestrone 3-methyl ether from the other conjugates. From intact rats the recovery of administered radioactivity was about 15% in the urine and 5% in the faeces over a period of several days and the radioactivity appeared to be largely protein-bound. The results demonstrate that injected oestrogen–glutathione conjugate undergoes conversion into N-acetylcysteine derivatives in vivo. Oestrogen–glutathione conjugates formed in the intact rat may be excreted in an apparently non-steroidal, possibly protein-bound form, which would not be detected by current analytical techniques.

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Proximal—distal sequence of development of the skeletal tissues in the penis of rat and the inductive effect of epithelium

Development ◽

10.1242/dev.92.1.133 ◽

1986 ◽

Vol 92 (1) ◽

pp. 133-143

Author(s):

Ryutaro Murakami ◽

Takeo Mizuno

Keyword(s):

Adult Male ◽

Inductive Effect ◽

Corpus Cavernosum ◽

Distal Segment ◽

Male Rats ◽

Chronological Order ◽

Adult Rats ◽

Phenotypic Differentiation ◽

Kidney Capsule ◽

Os Penis

The penis of adult rats comprises the corpus cavernosum penis and the proximal and distal segments of os penis which are situated proximal-distally in this order. Androgens are necessary for the phenotypic differentiation of these tissues. In the present study, genital tubercular mesenchyme of foetal rats was recombined with or without homologous or heterologous epithelia and transplanted beneath the kidney capsule of syngeneic adult male rats, and the development of the corpus cavernosum penis and the os penis in the transplants was examined. Only in the presence of epithelia can the genital tubercular mesenchyme acquire the capacity for differentiation into the corpus cavernosum penis, the proximal segment of os penis, and the distal segment of os penis in this chronological order. The inductive effect of epithelium is a permissive step in the differentiation of the os penis of rat. The epithelium seems to be necessary for the process of rudiment formation of the os penis and the corpus cavernosum penis.

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