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

P. P. L. Tam

doi:10.1242/dev.82.1.253

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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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 control of somitogenesis in mouse embryos

Development ◽

10.1242/dev.65.supplement.103 ◽

1981 ◽

Vol 65 (Supplement) ◽

pp. 103-128

Author(s):

P. P. L. Tam

Keyword(s):

Body Size ◽

Primitive Streak ◽

Mouse Embryos ◽

The Body ◽

Whole Body ◽

Axis Formation ◽

Presomitic Mesoderm ◽

Tail Bud ◽

Somite Formation ◽

Somitic Mesoderm

Somitogenesis in the mouse embryo commences with the generation of presumptive somitic mesoderm at the primitive streak and in the tail-bud mesenchyme. The presumptive somitic mesoderm is then organized into somite primordia in the presomitic mesoderm. These primordia undergo morphogenesis leading to the segmentation of somites at the cranial end of the presomitic mesoderm. Somite sizes at the time of segmentation vary according to the position of the somite in the body axis: the size of lumbar and sacral somites is nearly twice that of upper trunk somites and of tail somites. The size of the presomitic mesoderm, which is governed by the balance between the addition of cells at the caudal end and the removal of somites at the cranial end, changes during embryonic development. Somitogenesis is disturbed during the compensatory growth of mouse embryos which have suffered a drastic size reduction at the primitive-streak and early-organogenesis stages. The formation of somites is retarded and the upper trunk somites are formed at a smaller size. The embryo also follows an entirely different growth profile, but a normal body size is restored by the early foetal stage. The somite number is regulated to normal and this is brought about by an altered rate of somite formation and the adjustment of somite size in proportion to the whole body size. It is proposed that axis formation and somitogenesis are related morphogenetic processes and that embryonic growth controls the kinetics of somitogenesis, namely by regulating the number of cells allocated to each somite and the rate of somite formation.

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The somitogenetic potential of cells in the primitive streak and the tail bud of the organogenesis-stage mouse embryo

Development ◽

10.1242/dev.115.3.703 ◽

1992 ◽

Vol 115 (3) ◽

pp. 703-715 ◽

Cited By ~ 27

Author(s):

P.P. Tam ◽

S.S. Tan

Keyword(s):

Primitive Streak ◽

Mouse Embryos ◽

Paraxial Mesoderm ◽

Tail Bud ◽

Matrix Interaction ◽

Cell Matrix ◽

Age Related ◽

Somite Formation ◽

Lateral Mesoderm ◽

Host Embryo

The developmental potency of cells isolated from the primitive streak and the tail bud of 8.5- to 13.5-day-old mouse embryos was examined by analyzing the pattern of tissue colonization after transplanting these cells to the primitive streak of 8.5-day embryos. Cells derived from these progenitor tissues contributed predominantly to tissues of the paraxial and lateral mesoderm. Cells isolated from older embryos could alter their segmental fate and participated in the formation of anterior somites after transplantation to the primitive streak of 8.5-day host embryo. There was, however, a developmental lag in the recruitment of the transplanted cells to the paraxial mesoderm and this lag increased with the extent of mismatch of developmental ages between donor and host embryos. It is postulated that certain forms of cell-cell or cell-matrix interaction are involved in the specification of segmental units and that there may be age-related variations in the interactive capability of the somitic progenitor cells during development. Tail bud mesenchyme isolated from 13.5-day embryos, in which somite formation will shortly cease, was still capable of somite formation after transplantation to 8.5-day embryos. The cessation of somite formation is therefore likely to result from a change in the tissue environment in the tail bud rather than a loss of cellular somitogenetic potency.

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Interaction of epiblast and hypoblast in the formation of the primitive streak and the embryonic axis in chick, as revealed by hypoblast-rotation experiments

Development ◽

10.1242/dev.61.1.133 ◽

1981 ◽

Vol 61 (1) ◽

pp. 133-144

Author(s):

Yehudit Azar ◽

Hefzibah Eyal-Giladi

Keyword(s):

Marginal Zone ◽

Developmental Stages ◽

Primitive Streak ◽

Embryonic Axis

Three types of experiments were performed to determine the interaction between the epiblast and hypoblast for primitive streak formation: (1) Hypoblasts of blastoderms from stages XIII E.G & K to 3 H & H were separated from the epiblasts and rotated by 90° counterclockwise; (2) hypoblasts from stages XIII E.G & K to 3 H & H blastoderms were rotated by 180° (3) hypoblasts were exchanged between blastoderms of different developmental stages and placed at 90° counterclockwise to the axis of the recipient epiblast. In all blastoderms studied only a single PS developed. After rotation of the hypoblast by 90°, the direction of the PS was according to the orientation of the hypoblast at stage XIII, whereas at older stages it gradually shifted towards the axis of the epiblast. At stage 3− H & H the PS is already imprinted in the epiblast and cannot be shifted. After rotation of the hypoblast by 180° the PS originated at the point near the marginal zone at which the inductive part of the hypoblast interacted with a competent epiblast. Conclusions are drawn about the dynamics of the inductiveness of the hypoblast and the competence of the epiblast for the PS formation and orientation.

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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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Oral Character and Attitudes and Behavior Related to Food and Eating

Psychological Reports ◽

10.2466/pr0.1988.63.1.15 ◽

1988 ◽

Vol 63 (1) ◽

pp. 15-18 ◽

Cited By ~ 2

Author(s):

Jon K. Mills ◽

Jean Cunningham

Keyword(s):

Body Weight ◽

Developmental Stages ◽

Female College Students ◽

Adult Personality ◽

Adult Body ◽

Adult Body Weight ◽

Projective Measure ◽

And Behavior ◽

Attitudes And Behavior ◽

Early Developmental

Freudian theory predicts that adult personality characteristics and behavior will reflect unresolved conflicts from early developmental stages. In this study, a card from the Blum's Blacky test was used as a projective measure of oral conflict with 35 male and 61 female college students. The presence of such conflict was significantly associated with deviations from norms for body weight, greater variability in adult body weight, rating food as important, and eating more frequently. However, ratings of preoccupation with food were not significantly related to scores for oral conflict. These findings support predictions from psychoanalytic theory and also point to the continued usefulness of the Blacky test in psychoanalytic research.

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ELECTRON MICROSCOPIC EXAMINATION OF THE SITES OF NUCLEAR RNA SYNTHESIS DURING AMPHIBIAN EMBRYOGENESIS

The Journal of Cell Biology ◽

10.1083/jcb.26.3.937 ◽

1965 ◽

Vol 26 (3) ◽

pp. 937-958 ◽

Cited By ~ 104

Author(s):

Shuichi Karasaki

Keyword(s):

Rna Synthesis ◽

Developmental Stages ◽

Early Embryo ◽

Tail Bud ◽

Electron Microscopic ◽

Electron Microscopic Autoradiography ◽

Nuclear Rna Synthesis ◽

Nuclear Rna ◽

Chromatin Material ◽

Labeled Rna

The site of H3-uridine incorporation and the fate of labeled RNA during early embryo-genesis of the newt Triturus pyrrhogaster were studied with electron microscopic autoradiography. Isolated ectodermal and mesodermal tissues from the embryos were treated in H3-uridine for 3 hours and cultured in cold solution for various periods before fixation with OsO4 and embedding in Epon. At the blastula stage, the only structural component of the nucleus seen in electron micrographs is a mass of chromatin fibrils. At the early gastrula stage, the primary nucleoli originate as small dense fibrous bodies within the chromatin material. These dense fibrous nucleoli enlarge during successive developmental stages by the acquisition of granular components 150 A in diameter, which form a layer around them. Simultaneously larger granules (300 to 500 A) appear in the chromatin, and they fill the interchromatin spaces by the tail bud stage. Autoradiographic examination has demonstrated that nuclear RNA synthesis takes place in both the nucleolus and the chromatin, with the former consistently showing more label per unit area than the latter. When changes in the distribution pattern of radioactivity were studied 3 to 24 hours after immersion in isotope at each developmental stage, the following results were obtained. Labeled RNA is first localized in the fibrous region of the nucleolus and in the peripheral region of chromatin material. After longer culture in non-radioactive medium, labeled materials also appear in the granular region of the nucleolus and in the interchromatin areas. Further incubation gives labeling in cytoplasm.

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Recherches sur le rôle de la température dans la réalisation du phénotype chez des embryons de l'Amphibien Pleurodeles waltlii homozygotes pour la mutation thermosensible ac (ascite caudale)

Development ◽

10.1242/dev.34.1.221 ◽

1975 ◽

Vol 34 (1) ◽

pp. 221-252

Author(s):

Par Maria Fernandez ◽

Jean-Claude Beetschen

Keyword(s):

Embryonic Development ◽

Developmental Stages ◽

Fluid Collection ◽

Temperature Shift ◽

Temperature Sensitive ◽

Tail Bud ◽

Dorsal Fin ◽

Second Shift ◽

Pleurodeles Waltlii

1. At the feeding stage (st. 38), a high percentage (79 %) of Pleurodeles homozygous ac/ac larvae show bent tails after a persistent ascitic blister in the dorsal part of the fin, when embryonic development occurred at 12°C; about only 25 % of them are affected by abdominal and pericardic ascites; about 40 % can feed and survive. The larval phenotype is very different when embryonic development occurred at 23 °C, in which case tail growth appears to be normal, but 95 % larvae die, due to ascitic fluid collection in the abdominal and heart regions, marked anaemia and microcephaly. 2. The exchange of posterior neural plates and dorso-lateral epidermis between normal and mutant neurulae has shown that the localization of the blister in the dorsal fin is not dependent on autonomous properties of the mutant dorsal tissues, but should be considered as resulting from general disturbances in the mutant organism. 3. Experiments were performed, involving a temperature shift from 12 to 23°C or 23 to 12°C, occurring at various developmental stages from the end of gastrulation (stage 13) to the stage of spontaneous embryonic muscle contractions (stage 26). When the temperature shift was applied after the end of neurulation (stage 21), the caudal phenotype was statistically similar to that of larvae which had been bred continuously at the first temperature. Thus temperature-sensitive phases can be characterized between neurula stages 15 and 18 (for a 12–23° shift) or 15 and 21 (for a 23–12° shift). Similarly, abdominal ascites can be induced when embryos are kept at 23 °C till stage 23 (early tail-bud) only, and occurs much less frequently when embryos are kept at 12°C till stage 23 and then transferred to 23°C. 4. It could be concluded from these experiments that the caudal mutant phenotype is already temperature-determined during neurulation, before stage 21. Nevertheless, double temperature-shift experiments showed that the second shift could modify the results which would be obtained if the first shift only occurred. Paradoxical results were obtained, more than 90 % of the tail phenotypes being of the ‘warm type’ when the embryos were first kept at 12°C, then shifted up to 23 °C between stages 22 and 26, and shifted down again to 12°C. Such a treatment markedly lowers the percentage of bent tails (‘cold type’) from the percentage which would occur if ac/ac embryos were constantly kept at 23 °C after stage 21, but this longer warm treatment is of no effect of itself as compared to the case when the whole development occurs at 12°C (bent tails are predominant in this latter case). Thus, whereas the early determination of the position of the caudal blister can be considered as a stable phenomenon under given temperature conditions, it is not irreversible. 5. As compared to cold-bred larvae, thrice as many completely anaemic larvae (66 %) were obtained from ac/ac embryos kept at 23 °C between stages 21 and 26; this offers an opportunity for the experimental study of this anaemia. 6. Implications of these results for further analysis of temperature-sensitive mutations in cold-blooded vertebrates are suggested.

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