297 research outputs found
Development and degeneration of dorsal root ganglia in the absence of the HMG-domain transcription factor Sox10
No full textThe HMG-domain transcription factor Sox10 is essential for the development of various neural crest derived lineages including glia and neurons of the peripheral nervous system (PNS). Within the PNS the most striking defect is the complete absence of glial differentiation whereas neurogenesis seemed initially normal. A degeneration of motoneurons and sensory neurons occurred later in development. The mechanism that leads to the dramatic effects on the neural crest derived cell lineages in the dorsal root ganglia (DRG), however, has not been examined up to now. Here, we provide a detailed analysis of proliferation and apoptosis in the DRG during the time of their generation and lineage segregation (between E 9.5 and E 11.5). We show that both increased apoptosis as well as decreased proliferation of neural crest cells contribute to the observed hypomorphism
Parasitic copepods from Egyptian Red Sea fishes: Bomolochidae Claus, 1875
No full text© The Author(s) 2015
Open Access - This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The attached file is the published version of the article.NHM Repositor
Terminal differentiation of myelin-forming oligodendrocytes depends on the transcription factor Sox10
No full textSox10 is a high-mobility-group transcriptional regulator in early neural crest. Without Sox10, no glia develop throughout the peripheral nervous system. Here we show that Sox10 is restricted in the central nervous system to myelin-forming oligodendroglia. In Sox10-deficient mice progenitors develop, but terminal differentiation is disrupted. No myelin was generated upon transplantation of Sox10-deficient neural stem cells into wild-type hosts showing the permanent, cell-autonomous nature of the defect. Sox10 directly regulates myelin gene expression in oligodendrocytes, but does not control erbB3 expression as in peripheral glia. Sox10 thus functions in peripheral and central glia at different stages and through different mechanisms
Radial glia phagocytose axonal debris from degenerating over-extending axons in the developing olfactory bulb
No full textAxon targeting during the development of the olfactory system is not always accurate and numerous axons over-extend past the target layer into the deeper layers of the olfactory bulb. To date, the fate of the mis-targeted axons has not been determined. We hypothesised that following over-extension, the axons degenerate, and that cells within the deeper layers of the olfactory bulb phagocytose the axonal debris. We utilised a line of transgenic mice that expresses ZsGreen fluorescent protein in primary olfactory axons. We found that over-extending axons closely followed the filaments of radial glia present in the olfactory bulb during embryonic development. Following over-extension into deeper layers of the olfactory bulb, axons degenerated and radial glia responded by phagocytosing the resulting debris. We used in vitro analysis to confirm that the radial glia had phagocytosed debris from olfactory axons. We also investigated if the fate of over-extending axons was altered when the development of the olfactory bulb was perturbed. In mice that lacked Sox10, a transcription factor essential for normal olfactory bulb development, we observed a disruption to the morphology and positioning of radial glia and an accumulation of olfactory axon debris within the bulb. Our results demonstrate that during early development of the olfactory system, radial glia play an important role in removing over-extended axons from the deeper layers of the olfactory bulb.Full Tex
Semantic model-driven development of web service architectures.
No full textBuilding service-based architectures has become a major area of interest since the advent of Web services. Modelling these architectures is a central activity. Model-driven development is a recent approach to developing software systems based on the idea of making models the central artefacts for design representation, analysis, and code generation.
We propose an ontology-based engineering methodology for semantic model-driven composition and transformation of Web service architectures. Ontology technology as a logic-based knowledge representation and reasoning framework can provide answers to the needs of sharable and reusable semantic models and descriptions needed for service engineering. Based on modelling, composition and code generation techniques for service architectures, our approach provides a methodological framework for ontology-based semantic service architecture
Letter from Hubert Phillips to American Civil Liberties Union of Northern California, August 4, 1942
No full textLetter from Hubert Phillips to American Civil Liberties Union of Northern California, enclosing checks for $57 from F. C. Kellogg, Arthur E. Geschke, Claus Bertelsen, and Hubert Phillips. The letter states that the checks represent "the contributions of about twenty-five people made at a dinner held here recently to consider the phases of the status of citizens of Japanese ancestry and is to be applied specifically to helping prosecute the case of Miss Mitsuye Endo. Mr. F. C. Kellogg of the Fowler High School faculty was the author of the idea and deserves the credit for raising the enclosed contribution."The ACLU-Northern California case file records contain legal documents and correspondence pertaining to the case Ex parte Mitsuye Endo (1944), in which the United States Supreme court unanimously ruled that the federal government could not indefinitely detain United States citizens who were loyal to the government. Files include documents related to the Gordon Hirabayashi Supreme Court case Hirabayashi v. United States
Identification of Sox8 as a modifier gene in a mouse model of Hirschsprung disease reveals underlying molecular defect
No full textAbstractMice carrying heterozygous mutations in the Sox10 gene display aganglionosis of the colon and represent a model for human Hirschsprung disease. Here, we show that the closely related Sox8 functions as a modifier gene for Sox10-dependent enteric nervous system defects as it increases both penetrance and severity of the defect in Sox10 heterozygous mice despite having no detectable influence on enteric nervous system development on its own. Sox8 exhibits an expression pattern very similar to Sox10 with occurrence in vagal and enteric neural crest cells and later confinement to enteric glia. Loss of Sox8 alleles in Sox10 heterozygous mice impaired colonization of the gut by enteric neural crest cells already at early times. Whereas proliferation, apoptosis, and neuronal differentiation were normal for enteric neural crest cells in the gut of mutant mice, apoptosis was dramatically increased in vagal neural crest cells outside the gut. The defects in enteric nervous system development of mice with Sox10 and Sox8 mutations are therefore likely caused by a reduction of the pool of undifferentiated vagal neural crest cells. Our study suggests that Sox8 and Sox10 are jointly required for the maintenance of these vagal neural crest stem cells
The Democratic Welfare State: A European Regime Under the Strain of European Integration. IHS Political Science Series: 2000, No. 68
No full textStates are organizations of governance that apply to the people living in a defined territory. But in order to sustain such governance, the people must not just individually obey the law, but also colletively conceive of themselves as "We, the People..", with whom the law originates. For only if I, the individual citizen, have reasons to trust that, they, my fellow citizens, are actually willing to also obey the law, I’ll do so myself. This indispensible sense of belonging to a civic community can be based upon a variety of factors: ethno-cultural, linguistic, civic republican (as in "constitutional patriotism") or social justice. Applying this notion of an indispensible civic infrastructure to the case of European integration, the author discusses a number of potential sources from which the view might be derived that what happens in Europe is a matter of "us, the Europeans". In the absence of a democratic regime in Europe, as well as a European welfare state (to say nothing about a strictly "European culture"), it is not easy to find out possible foundations of European "identity"
Interannual Variability in Carbon Dioxide Flux from a High Arctic Fen Estimated by Measurements and Modeling
No full textThe response of high arctic ecosystems' carbon dioxide exchange to changing climate is uncertain and may be important from a climate-change perspective. In this study, the net ecosystem carbon dioxide exchange during four growing seasons is examined by combining measurements and modeling from a high arctic fen in northeastern Greenland. The summer-season net ecosystem exchange shows large interannual variations, fluctuating from an uptake of −50 g C m−2 to −123 g C m−2. Through ecosystem modeling, we can observe that leaf area index development and the maximum Rubisco capacity are more important controls on the interannual variability of net ecosystem carbon dioxide exchange than meteorological conditions. Furthermore, we present a hypothesis linking the interannual variability in maximum Rubisco capacity with leaf nitrogen content and leaf area index development. This hypothesis may provide a method to model seasonal net ecosystem carbon dioxide exchange in detail without having to resort to elaborate fitting procedures using measured carbon dioxide flux data.This article was published in Arctic, Antarctic, and Alpine Research (2005), and this Version of Record is archived in RUcore with permission. The published article is available from the Institute of Arctic and Alpine Research (INSTAAR) at: http://instaar.colorado.edu/aaar/journal_issues/abstract.php?id=2353Peer reviewe
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