Fine structural differentiation of germ layers in the mouse at the time of mesoderm formation

1979 ◽  
Vol 194 (1) ◽  
pp. 125-141 ◽  
Author(s):  
Bruce E. Batten ◽  
Jack L. Haar
Keyword(s):  
Structural Differentiation ◽  
Germ Layers ◽  
Mesoderm Formation

The snail gene required for mesoderm formation in Drosophila is expressed dynamically in derivatives of all three germ layers

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 983-992 ◽  
Author(s):  
A. Alberga ◽  
J.L. Boulay ◽  
E. Kempe ◽  
C. Dennefeld ◽  
M. Haenlin
Keyword(s):  
Zinc Finger Protein ◽  
Regional Distribution ◽  
Second Phase ◽  
Germ Layers ◽  
Mesoderm Formation ◽  
Rna Accumulation ◽  
Genetically Determined ◽  
Derivatives Of ◽  
Late Stages

The zygotic effect gene snail (sna) encodes a zinc-finger protein required for mesoderm formation in Drosophila embryos. By in situ analysis, sna transcripts are first detected at syncytial blastoderm and persist until very late stages of embryogenesis. Expression of sna is transient and is observed in tissues derived from all three germ layers. Prior to germband elongation, sna RNA accumulation is consistent with its genetically determined role in mesoderm formation. Starting at germband elongation, a second phase of sna expression appears to be initiated, characterized by a highly dynamic accumulation of transcripts in the developing central and peripheral nervous systems. Translation of sna RNA is apparently delayed as the sna protein is not detected before the onset of gastrulation. Its regional distribution generally correlates with that of sna transcripts. The complex pattern of sna expression strongly suggests that the function of the gene is not restricted to mesoderm formation.

Mesoderm induction in Xenopus is a zygotic event regulated by maternal VegT via TGFbeta growth factors

Development ◽  
1999 ◽  
Vol 126 (24) ◽  
pp. 5759-5770 ◽  
Author(s):  
M. Kofron ◽  
T. Demel ◽  
J. Xanthos ◽  
J. Lohr ◽  
B. Sun ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Growth Factors ◽  
Body Axis ◽  
Mesoderm Induction ◽  
Equatorial Zone ◽  
Wild Type ◽  
Germ Layers ◽  
Endogenous Factors ◽  
Mesoderm Formation ◽  
Mesodermal Tissue

The maternal transcription factor VegT is important for establishing the primary germ layers in Xenopus. In previous work, we showed that the vegetal masses of embryos lacking maternal VegT do not produce mesoderm-inducing signals and that mesoderm formation in these embryos occurred ectopically, from the vegetal area rather than the equatorial zone of the blastula. Here we have increased the efficiency of the depletion of maternal VegT mRNA and have studied the effects on mesoderm formation. We find that maternal VegT is required for the formation of 90% of mesodermal tissue, as measured by the expression of mesodermal markers MyoD, cardiac actin, Xbra, Xwnt8 and alphaT4 globin. Furthermore, the transcription of FGFs and TGFbetas, Xnr1, Xnr2, Xnr4 and derriere does not occur in VegT-depleted embryos. We test whether these growth factors may be endogenous factors in mesoderm induction, by studying their ability to rescue the phenotype of VegT-depleted embryos, when their expression is restricted to the vegetal mass. We find that Xnr1, Xnr2, Xnr4 and derriere mRNA all rescue mesoderm formation, as well as the formation of blastopores and the wild-type body axis. Derriere rescues trunk and tail while nr1, nr2 and nr4 rescue head, trunk and tail. We conclude that mesoderm induction in Xenopus depends on a maternal transcription factor regulating these zygotic growth factors.

Intraocular differentiation of rat egg cylinders

Development ◽  
1965 ◽  
Vol 13 (3) ◽  
pp. 243-253
Author(s):  
B. Levak-Švajger ◽  
N. Škreb
Keyword(s):  
Anterior Chamber ◽  
The Other ◽  
Rat Embryo ◽  
Germ Layers ◽  
Other Hand ◽  
Mesoderm Formation ◽  
Development Proceeds ◽  
Suitable Environment

The anterior chamber of the eye is a suitable environment for testing the capacities of embryonic shields of the mouse to differentiate, as has been shown by Grobstein (1951). The development proceeds at a slower rate than usually and no morphogenesis is observed, although many identifiable tissues are found. The differentiation progressively increases as later stages are used. On the other hand, if younger stages, e.g. tubal ova or morulae, are transplanted (Runner, 1947), no histogenesis can be obtained although the germ layers are formed. The purpose of the present study has been to test the capacity of differentiation of two distinctly defined stages of rat embryo: one prior to mesoderm formation and the other with the mesoderm already formed. It is well known (Huber, 1916; Wilson, 1954; Mulnard, 1955) that the onset of mesoderm formation occurs in the rat during the 9th day of gestation, and this has been verified by our own material.

The Intertwined Histories of Personality and Social Psychology

2018 ◽  
pp. 10-34
Author(s):  
Thomas F. Pettigrew
Keyword(s):  
Social Psychology ◽  
World War I ◽  
Bounded Rationality ◽  
World War ◽  
Structural Differentiation ◽  
Interaction Models

Personality and social psychology histories have been closely intertwined for more than a century. Several critical differences have at times acted to separate the fields. One such divergence involved their models of humans—whether largely irrational (personality emphasis) or largely rational (social emphasis). This difference has subsided with their joint acceptance of a “bounded rationality.” More important has been their difference in focus—the microlevel of the person versus the mesolevel of the group and situation. Now, both fields largely agree on a variety of interaction models that include both the person and the situation. We trace these tensions between the two fields across eras: (a) origins through World War I (1890–1919); (b) early developments (1920–1935); (c) war influences (1936–1950); (d) structural differentiation and slow acceptance (1951–1965); (e) dual crises (1966–1985); (f) coming back together again (1986–2000); and (7) continued fusion (2001–present).

scholarly journals Reproductive biology, embryonic development and matrotrophy in the phylactolaemate bryozoan Plumatella casmiana

2021 ◽  
Author(s):  
Julian Bibermair ◽  
Andrew N. Ostrovsky ◽  
Andreas Wanninger ◽  
Thomas Schwaha
Keyword(s):  
Embryonic Development ◽  
Embryo Sac ◽  
The Body ◽  
Transcellular Transport ◽  
Cell Contacts ◽  
Transmission Electron ◽  
Distal Side ◽  
Early Embryos ◽  
Mesoderm Formation ◽  
Cytoplasmic Processes

AbstractBryozoa is a phylum of aquatic, colonial suspension-feeders within the Lophotrochozoa. In the Phylactolaemata embryonic development occurs in an internal brood sac on the body wall accompanied by extraembryonic nutrition. Owing to previous contradictive descriptions, many aspects of their sexual reproduction require restudy. Consequently, this study analyses embryogenesis of the freshwater bryozoan Plumatella casmiana by serial sections, 3D reconstruction and transmission electron microscopy. Early embryos cleave and soon develop into blastulae with a small central cavity. The mesoderm forms by delamination starting from the distal side towards the proximal end. In later embryos two polypides form on the posterior side that ultimately will be covered by a ciliated mantle in the larva. Embryos increase in size during development and form temporary cell contacts to the embryo sac. Mesodermal cells of the embryo sac show signs of transcellular transport indicating that embryos are nourished by transferring nutrients from the maternal coelom towards the brood cavity. This study clarifies several details such as mesoderm formation and the onset of bud development. Embryos are connected to their respective embryo sacs by a variety of temporary cytoplasmic processes formed by both tissues during embryogenesis, including a ‘placental’ ring zone. Although ultrastructural data of these cell contacts are not entirely conclusive about their function, we suggest that embryos absorb nutrients via the entire surface. The close opposition of embryos to the embryo sac implies placentation as matrotrophic mode in phylactolaemate bryozoans, with embryo sacs acting as placental analogues.

Concurrent Thoracic Spinal Intradural Extramedullary Epidermoid and Neurenteric Cyst in a Spinal Dysraphism Child

2021 ◽  
pp. 1-7
Author(s):  
Rajeev Sharma ◽  
Swati Mahajan ◽  
Minakshi Bhardwaj ◽  
Laxmi Naraian Gupta ◽  
Deepak Gupta
Keyword(s):  
Surgical Planning ◽  
English Literature ◽  
Spinal Dysraphism ◽  
Neurenteric Cyst ◽  
Germ Layers ◽  
Case Presentation ◽  
Spinal Lesions ◽  
Congenital Origin ◽  
Thoracic Spinal ◽  
Intradural Extramedullary

<b><i>Introduction:</i></b> Intraspinal epidermoid cysts are congenital or acquired in origin; whereas intraspinal neurenteric cysts (NECs) are of congenital origin. Their individual association with spinal dysraphism and vertebral segmentation anomalies is very well known. <b><i>Case presentation:</i></b> We hereby report a case of concurrent intradural extramedullary epidermoid and NEC at adjacent vertebral levels in a spinal dysraphism child, not reported in English Literature till now. <b><i>Conclusion:</i></b> Multiple spinal lesions related to any/all of the 3 germ layers can coexist at same or adjacent vertebral levels in the same patient and surgical planning shown to be done accordingly.

scholarly journals Rhesus iPSC Safe Harbor Gene-Editing Platform for Stable Expression of Transgenes in Differentiated Cells of All Germ Layers

2017 ◽  
Vol 25 (1) ◽  
pp. 44-53 ◽  
Author(s):  
So Gun Hong ◽  
Ravi Chandra Yada ◽  
Kyujoo Choi ◽  
Arnaud Carpentier ◽  
T. Jake Liang ◽  
...  
Keyword(s):  
Gene Editing ◽  
Stable Expression ◽  
Safe Harbor ◽  
Germ Layers ◽  
Differentiated Cells
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