Articles tagués twt

Modeling Gastrulation in the Chick Embryo: Formation of the Primitive Streak

Modeling Gastrulation in the Chick Embryo: Formation of the Primitive Streak

Bakhtier Vasiev, Ariel Balter, Mark Chaplain, James A. Glazier, Cornelis J. Weijer

PLoS ONE 5(5): e10571. doi:10.1371/journal.pone.0010571


And always, just two vortices 😉

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Non-redundant roles for Profilin2 and Profilin1 during vertebrate gastrulation

Non-redundant roles for Profilin2 and Profilin1 during vertebrate gastrulation

Deepak K. Khadka, Wei Liu and Raymond Habas

Developmental Biology Article in Press, Corrected Proof doi:10.1016/j.ydbio.2009.06.008

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Clarifying tetrapod embryogenesis, a physicist’s point of view

Clarifying tetrapod embryogenesis, a physicist’s point of view

V. Fleury

Eur. Phys. J. Appl. Phys. 45, 30101 (2009) doi: 10.1051/epjap/2009033


Well, Fleury failed to hit my e-mail to announce his paper, despite the fact that he repeatedly tried to troll around. Thanks to SDX I’m informed now and I’ll give it a reading and I’ll comment ASAP.
It’s a pity that the paper didn’t made it to a biology journal and one where comments and questions could be posted. The discussion, if any, will be much more difficult. [edit the paper may be discussed at « Clarifying Tetrapod Embryogenesis, a biologist’s reply« ]
As it is an Free Access paper you can get it easily. Unfortunately not an Open Access one. Lire la suite »

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Superiority, Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs

Superiority, Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs

Stephen L. Brusatte, Michael J. Benton, Marcello Ruta, Graeme T. Lloyd

Science 12 September 2008: Vol. 321. no. 5895, pp. 1485 – 1488 DOI: 10.1126/science.1161833

Je ne m’intéresse pas particulièrement aux dinosaures d’habitude, mais ce papier est une illustration du « météore qui tombe à travers la gueule » du génotype prometteur. Ou, sérieusement, des accidents naturels qui influencent l’évolution, ne tenant pas compte de la direction qu’elle suivait précédemment. Le genre d’exemples qui s’opposent à des points de vues sur le « sens de l’évolution » et qui montrent que l’environnement peut influencer plus que le développement d’un individu particulier 😉


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L2/R2, un an déjà…

L2R2-failw.jpg

Toujours manquants à l’appel !

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Molecular Characterization of the Gastrula in the Turtle Emys orbicularis: An Evolutionary Perspective on Gastrulation

Coolen M, Nicolle D, Plouhinec JL, Gombault A, Sauka-Spengler T, et al. (2008 ) Molecular Characterization of the Gastrula in the Turtle Emys orbicularis: An Evolutionary Perspective on Gastrulation. PLoS ONE 3(7): e2676. doi:10.1371/journal.pone.0002676

Due to the presence of a blastopore as in amphibians, the turtle has been suggested to exemplify a transition form from an amphibian- to an avian-type gastrulation pattern. In order to test this hypothesis and gain insight into the emergence of the unique characteristics of amniotes during gastrulation, we have performed the first molecular characterization of the gastrula in a reptile, the turtle Emys orbicularis. The study of Brachyury, Lim1, Otx2 and Otx5 expression patterns points to a highly conserved dynamic of expression with amniote model organisms and makes it possible to identify the site of mesoderm internalization, which is a long-standing issue in reptiles. Analysis of Brachyury expression also highlights the presence of two distinct phases, less easily recognizable in model organisms and respectively characterized by an early ring-shaped and a later bilateral symmetrical territory. Systematic comparisons with tetrapod model organisms lead to new insights into the relationships of the blastopore/blastoporal plate system shared by all reptiles, with the blastopore of amphibians and the primitive streak of birds and mammals. The biphasic Brachyury expression pattern is also consistent with recent models of emergence of bilateral symmetry, which raises the question of its evolutionary significance.

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Separating genetic and hemodynamic defects in neuropilin 1 knockout embryos

Separating genetic and hemodynamic defects in neuropilin 1 knockout embryos

Elizabeth A. V. Jones, Li Yuan, Christine Breant, Ryan J. Watts and Anne Eichmann

Development 135, 2479-2488 (2008 ) doi: 10.1242/dev.014902

Je ne sais pas si vous avez remarqué, je suis très VEGF ces derniers temps. Isoformes et récepteurs et régulation d’expression de gènes à partir de différentes voies de signalisation, etc. Je suis en train de me régaler avec. Aujourd’hui la récolte a été étonnante, après un croisement de mots clés avec la neuropilin 1, NRP1 pour les intimes. Abondante et avec au moins un petit joyau dedans, pour mon tag « twt » 🙂

En fait il semble bien que « time is telling« , un autre tag à metre en place ? « tit » ? Yep, je vais commencer à l’utiliser à partir de ce post.

Déjà le titre était intéressant (Separating genetic and hemodynamic defects), prometteur …

Eh bien, j’aurais parié pour génétique (vous vous en doutiez non ?) dans la cas du knockout Nrp1.

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Regulatory constraints in the evolution of the tetrapod limb anterior–posterior polarity

Regulatory constraints in the evolution of the tetrapod limb anterior–posterior polarity

Basile Tarchini, Denis Duboule and Marie Kmita

Nature 443, 985-988 (26 October 2006) | doi:10.1038/nature05247

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Tbx6 Regulates Left/Right Patterning in Mouse Embryos through Effects on Nodal Cilia and Perinodal Signaling

Hadjantonakis A-K, Pisano E, Papaioannou VE (2008) Tbx6 Regulates Left/Right Patterning in Mouse Embryos through Effects on Nodal Cilia and Perinodal Signaling. PLoS ONE 3(6): e2511. doi:10.1371/journal.pone.0002511

journal.pone.0002511.g001.png

Figure 1. Laterality defects in E9.5 Tbx6 mutant embryos.
(A) Ventral view of a wild type (wt) embryo with normal heart looping and (B) a Tbx6 homozygous mutant embryo (−/−) with reversed heart looping. The arrow indicates the direction of looping from the inflow to the outflow tract. ( C, D) SEM of the heart of a wild type embryo and mutant embryo with reversed looping, respectively. (E) Embryos still enclosed in the yolk sac with the placenta attached or (F) with the placenta removed and the yolk sac everted. The wild type embryo shows the normal arrangement of placenta, tail, and vitelline vessels, whereas the mutant has reversed orientation.

Une mutation avec des effets morphogéniques, encore une. Mais où vont-ils s’arrêter ? 😀

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An Fgf/Gremlin inhibitory feedback loop triggers termination of limb bud outgrowth

An Fgf/Gremlin inhibitory feedback loop triggers termination of limb bud outgrowth

Jamie M. Verheyden & Xin Sun

Nature, doi:10.1038/nature07085

Encore une de ces études de mutants pour produire un modèle rendant compte d’un mécanisme, qui en plus ose ne pas être mécanique 😉

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