scholarly journals The Many Faces of Xenopus: Xenopus laevis as a Model System to Study Wolf–Hirschhorn Syndrome

2019 ◽  
Vol 10 ◽  
Author(s):  
Micaela Lasser ◽  
Benjamin Pratt ◽  
Connor Monahan ◽  
Seung Woo Kim ◽  
Laura Anne Lowery
Keyword(s):  
Xenopus Laevis ◽  
Model System ◽  
The Many

Coupled-pair theories and Davidson-type corrections for quasidegenerate states: The H4 model revisited

1988 ◽  
Vol 53 (9) ◽  
pp. 1919-1942 ◽  
Author(s):  
Josef Paldus ◽  
Paul E. S. Wormer ◽  
Marc Benard
Keyword(s):  
Electron Correlation ◽  
Model System ◽  
Coupled Cluster ◽  
Electron Model ◽  
Hydrogen Molecules ◽  
Double Zeta ◽  
Correlation Problem ◽  
Variational Approaches ◽  
Cluster Type ◽  
The Many

The performance of various variational and non-variational approaches to the many-electron correlation problem is examined for a simple four-electron model system consisting of two stretched hydrogen molecules in trapezoidal, rectangular and linear configurations, in which the degree of quasi-degeneracy can be continuously varied from a non-degenerate to an almost degenerate situation. In contrast to an earlier work (K. Jankowski and J. Paldus, Int. J. Quantum Chem. 18, 1243 (1980)) we employ a double-zeta plus polarization basis and examine both single reference and multireference configuration interaction and coupled-cluster-type approaches. The performance of various Davidson-type corrections is also investigated.

Opium poppy: a model system to investigate alkaloid biosynthesis in plants

2005 ◽  
Vol 83 (10) ◽  
pp. 1189-1206 ◽  
Author(s):  
Peter J. Facchini ◽  
David A. Bird ◽  
Richard Bourgault ◽  
Jillian M. Hagel ◽  
David K. Liscombe ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Secondary Metabolism ◽  
Secondary Compounds ◽  
Model System ◽  
Opium Poppy ◽  
Mentha Piperita ◽  
Alkaloid Biosynthesis ◽  
Model Legume ◽  
Integrative Research ◽  
The Many

Remarkable progress on the biology of plant secondary metabolism has recently been realized. The application of advanced biochemistry, molecular, cellular, and genomic methodologies has revealed biological paradigms unique to the biosynthesis of secondary metabolites, including alkaloids, flavonoids, glucosinolates, phenylpropanoids, and terpenoids. The use of model plant systems has facilitated integrative research on the biosynthesis and regulation of each group of natural products. The model legume, Medicago truncatula Gaertn., plays a key role in studies on phenylpropanoid and flavonoid metabolism. Mint ( Mentha × piperita L.) and various conifers are the systems of choice to investigate terpenoid metabolism, whereas members of the mustard family (Brassica spp.) are central to work on glucosinolate pathways. Arabidopsis thaliana (L.) Heynh. is also used to study the biosynthesis of most secondary compounds, except alkaloids. Unlike other categories of secondary metabolites, the many structural types of alkaloids are biosynthetically unrelated. The biology of each group is unique, although common paradigms are also apparent. Opium poppy ( Papaver somniferum L.) produces a large number of benzylisoquinoline alkaloids and has begun to challenge Madigascar periwinkle ( Catharanthus roseus (L.) G. Don), which accumulates monoterpenoid indole alkaloids, as the most versatile model system to study alkaloid metabolism. An overview of recent progress on the biology of plant alkaloid biosynthesis, with a focus on benzylisoquinoline alkaloid pathways in opium poppy and related species, highlights the emergence of opium poppy as an important model system to investigate secondary metabolism.

scholarly journals A temporally resolved transcriptome for developing “Keller” explants of the Xenopus laevis dorsal marginal zone

2020 ◽  
Author(s):  
Anneke D. Kakebeen ◽  
Robert Huebner ◽  
Asako Shindo ◽  
Kujin Kwon ◽  
Taejoon Kwon ◽  
...  
Keyword(s):  
Gene Expression ◽  
Xenopus Laevis ◽  
Marginal Zone ◽  
Model System ◽  
Extensive Study ◽  
Convergent Extension ◽  
Time Resolved ◽  
Vertebrate Embryos ◽  
Global Patterns ◽  
Central Paradigm

AbstractExplanted tissues from vertebrate embryos reliably develop in culture and have provided essential paradigms for understanding embryogenesis, from early embryological investigations of induction, to the extensive study of Xenopus animal caps, to the current studies of mammalian gastruloids. Cultured explants of the Xenopus dorsal marginal zone (“Keller” explants) serve as a central paradigm for studies of convergent extension cell movements, yet we know little about the global patterns of gene expression in these explants. In an effort to more thoroughly develop this important model system, we provide here a time-resolved bulk transcriptome for developing Keller explants.

scholarly journals Gastrulation movements provide an early marker of mesoderm induction in Xenopus laevis

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 339-349 ◽  
Author(s):  
K. Symes ◽  
J.C. Smith
Keyword(s):  
Cell Division ◽  
Xenopus Laevis ◽  
Early Response ◽  
Model System ◽  
Mesoderm Induction ◽  
Animal Pole ◽  
Inductive Interaction ◽  
Vegetal Pole ◽  
Pole Cells ◽  
General Appearance

The first inductive interaction in amphibian development is mesoderm induction, in which an equatorial mesodermal rudiment is induced from the animal hemisphere under the influence of a signal from vegetal pole blastomeres. We have recently discovered that the Xenopus XTC cell line secretes a factor which has the properties we would expect of a mesoderm-inducing factor. In this paper, we show that an early response to this factor by isolated Xenopus animal pole regions is a change in shape, involving elongation and constriction. We show by several criteria, including general appearance, timing, rate of elongation and the nonrequirement for cell division that these movements resemble the events of gastrulation. We also demonstrate that the movements provide an early, simple and reliable indicator of mesoderm induction and are of use in providing a ‘model system’ for the study of mesoderm induction and gastrulation. For example, we show that the timing of gastrulation movements does not depend upon the time of receipt of a mesoderm-induction signal, but on an intrinsic gastrulation ‘clock’ which is present even in those animal pole cells that would not nomally require it.

Mesoderm-inducing factors and the control of gastrulation

Development ◽  
1992 ◽  
Vol 116 (Supplement) ◽  
pp. 127-136 ◽  
Author(s):  
J. C. Smith ◽  
J. E. Howard
Keyword(s):  
Xenopus Laevis ◽  
Molecular Basis ◽  
Model System ◽  
Inductive Interaction ◽  
Inducing Factors ◽  
Gastrulation Movement ◽  
Mesoderm Inducing Factors ◽  
Suitable System ◽  
Do So

One of the reasons that we know so little about the control of vertebrate gastrulation is that there are very few systems available in which the process can be studied in vitro. In this paper, we suggest that one suitable system might be provided by the use of mesoderm-inducing factors. In amphibian embryos such as Xenopus laevis, gastrulation is driven by cells of the mesoderm, and the mesoderm itself arises through an inductive interaction in which cells of the vegetal hemisphere of the embryo emit a signal which acts on overlying equatorial cells. Several factors have recently been discovered that modify the pattern of mesodermal differentiation or induce mesoderm from presumptive ectoderm. Some of these mesoderm-inducing factors will also elicit gastrulation movements, which provides a powerful model system for the study of gastrulation, because a population of cells that would not normally undertake the process can be induced to do so. In this paper, we use mesoderm-inducing factors to attempt to answer four questions. How do cells know when to gastrulate? How do cells know what kind of gastrulation movement to undertake? What is the cellular basis of gastrulation? What is the molecular basis of gastrulation?

scholarly journals New frontiers in human cell biology and medicine: Can pluripotent stem cells deliver?

2012 ◽  
Vol 199 (4) ◽  
pp. 577-581 ◽  
Author(s):  
Lawrence S.B. Goldstein
Keyword(s):  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Cell Biology ◽  
Model System ◽  
Human Model ◽  
Human Stem Cells ◽  
Policy Issues ◽  
The Many ◽  
Medical Policy ◽  
Lateral Sclerosis

Human pluripotent stem cells provide enormous opportunities to treat disease using cell therapy. But human stem cells can also drive biomedical and cell biological discoveries in a human model system, which can be directly linked to understanding disease or developing new therapies. Finally, rigorous scientific studies of these cells can and should inform the many science and medical policy issues that confront the translation of these technologies to medicine. In this paper, I discuss these issues using amyotrophic lateral sclerosis as an example.

Optimization for Sustainability of Integrated Ecological-Economic Model System of Planet

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
M. Schwarz ◽  
U. Diwekar
Keyword(s):  
Economic Model ◽  
Model System ◽  
Non Linear Programming ◽  
Ecological Economic ◽  
Regulatory Policies ◽  
Dynamic Relationship ◽  
Economic Framework ◽  
Per Capita ◽  
The Many ◽  
Per Capita Consumption

In order to successfully understand and attempt to increase the sustainability of a system, the dynamic relationship between the many dimensions of sustainability need to be understood. Through the use of mathematical models, future scenarios can be studied which can be used to possibly develop policy guidelines. The model used in this article is an integrated ecological-economic model which incorporates a simplified ecological food web, a macro-economic framework, and a rudimentary legal system. By altering certain constraints within the model, the scenarios of a population explosion and an increase in per capita consumption can be evaluated. Dynamic optimization, specifically discretized non-linear programming, is then used to develop regulatory policies using Fisher Information as a measure of sustainability.

The egg of Xenopus laevis: A model system for studying cell activation

1989 ◽  
Vol 28 (2) ◽  
pp. 71-93 ◽  
Author(s):  
Michel Charbonneau ◽  
Nathalie Grandin
Keyword(s):  
Xenopus Laevis ◽  
Cell Activation ◽  
Model System
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