238 research outputs found
The mean curvature of cylindrically bounded submanifolds
We give an estimate of the mean curvature of a complete submanifold lying
inside a closed cylinder in a product Riemannian manifold
. It follows that a complete hypersurface of given
constant mean curvature lying inside a closed circular cylinder in Euclidean
space cannot be proper if the circular base is of sufficiently small radius. In
particular, any possible counterexample to a conjecture of Calabion complete
minimal hypersurfaces cannot be proper. As another application of our method,
we derive a result about the stochastic incompleteness of submanifolds with
sufficiently small mean curvature.Comment: First version (December 2008). Final version, including new title
(February 2009). To appear in Mathematische Annale
Identification and Analysis of Conserved cis-Regulatory Regions of the MEIS1 Gene
Meis1, a conserved transcription factor of the TALE-homeodomain class, is expressed in a wide variety of tissues during development. Its complex expression pattern is likely to be controlled by an equally complex regulatory landscape. Here we have scanned the Meis1 locus for regulatory elements and found 13 non-coding regions, highly conserved between humans and teleost fishes, that have enhancer activity in stable transgenic zebrafish lines. All these regions are syntenic in most vertebrates. The composite expression of all these enhancer elements recapitulate most of Meis1 expression during early embryogenesis, indicating they comprise a basic set of regulatory elements of the Meis1 gene. Using bioinformatic tools, we identify a number of potential binding sites for transcription factors that are compatible with the regulation of these enhancers. Specifically, HHc2:066650, which is expressed in the developing retina and optic tectum, harbors several predicted Pax6 sites. Biochemical, functional and transgenic assays indicate that pax6 genes directly regulate HHc2:066650 activity.This work was funded through grants BFU2009-07044 (MICINN) and Proyecto de Excelencia CVI 2658 (Junta de Andalucía) to FC and BFU2010-14839 (MICINN), CSD2007-00008 and Proyecto de Excelencia CVI-3488 to JLGS. JLR is a recipient of a JAE-DOC contract from the Spanish National Research Council (CSIC)
Sox21a is requiered for posterior lateral line patterning by regulating Fgf signalling
Resumen del póster presentado al IX Meeting of the Spanish Society for Developmental Biology celebrado en Granada del 12 al 14 de noviembre de 2012.Peer Reviewe
Monitoramento e percepção do ambiente alimentar da Universidade Federal do Rio de Janeiro
Bolsa PIBIC - CNPQAs relações entre os indivíduos e o ambiente têm sido foco de estudos uma vez que os espaços onde são comercializados alimentos podem ser influenciadores das escolhas e comportamentos alimentares. Nessa perspectiva, evidencia-se o ambiente universitário como estratégico, por influenciar as práticas alimentares da comunidade acadêmica. Este trabalho tem como objetivo conhecer a dinâmica do ambiente alimentar da Universidade Federal do Rio de Janeiro, campus Cidade Universitária. Dois inquéritos, o primeiro em 2015 e o segundo em 2017, foram realizados nos serviços de alimentação permissionários localizados no campus Cidade Universitária da Universidade Federal do Rio de Janeiro. Foi utilizado um questionário validado composto por questões sobre caracterização do estabelecimento, oferta de alimentos e bebidas, entre outros temas. Foram avaliados 52 e 58 estabelecimentos, respectivamente, no primeiro e segundo inquérito. Em ambos os momentos de avaliação houve predomínio de estabelecimentos mistos (venda de lanches e refeições) seguido por lanchonete. Observou-se que os alimentos considerados saudáveis ofertados com maior frequência foram os legumes e verduras cruas, leguminosas e legumes e verduras cozidas. Já dentre os alimentos considerados não saudáveis, os molhos industrializados, sanduíches ou crepes, salgados fritos e assados e balas foram os mais disponíveis em ambos inquéritos. Foi realizado um estudo qualitativo por meio da técnica do grupo focal com a participação de docentes, discentes e técnico-administrativos para avaliar a percepção em relação ao ambiente alimentar da universidade. As principais barreiras para a promoção da alimentação saudável descritas foram: falta de estrutura de copas para consumo dos alimentos trazidos de casa, preço dos alimentos considerados saudáveis nos estabelecimentos permissionários de alimentação, fila do restaurante universitário. O ambiente alimentar universitário investigado pouco contribuiu para promoção da alimentação saudável no campus. A avaliação mais abrangente sobre o ambiente alimentar da universidade está sendo realizada para que estratégias que visem mudanças no perfil dos alimentos comercializados sejam testadas e implementadas
Restless Legs Syndrome-associated intronic common variant in Meis1 alters enhancer function in the developing telencephalon
This article, published in Genome Research, is available under a Creative Commons License (Attribution-NonCommercial 3.0 Unported).-- et al.Genome-wide association studies (GWAS) identified the MEIS1 locus for Restless Legs Syndrome (RLS), but causal single nucleotide polymorphisms (SNPs) and their functional relevance remain unknown. This locus contains a large number of highly conserved noncoding regions (HCNRs) potentially functioning as cis-regulatory modules. We analyzed these HCNRs for allele-dependent enhancer activity in zebrafish and mice and found that the risk allele of the lead SNP rs12469063 reduces enhancer activity in the Meis1 expression domain of the murine embryonic ganglionic eminences (GE). CREB1 binds this enhancer and rs12469063 affects its binding in vitro. In addition, MEIS1 target genes suggest a role in the specification of neuronal progenitors in the GE, and heterozygous Meis1-deficient mice exhibit hyperactivity, resembling the RLS phenotype. Thus, in vivo and in vitro analysis of a common SNP with small effect size showed allele-dependent function in the prospective basal ganglia representing the first neurodevelopmental region implicated in RLS.The project was supported by Fritz-Thyssen-Stiftung, Cologne, Germany (10.09.2.146; 10.12.2.183), KKF-TUM (8766156), DAAD (0811963), and COST (“HOX and TALE homeoproteins in Development and Disease”). B.S. was partially supported by DFG grants (WI 1820/4-1; WI 1820/5-1) and a TUM-Excellence stipend. The KORA study was financed by the Helmholtz Zentrum München, which is funded by the German Federal Ministry of Education and Research (BMBF) and by the State of Bavaria. KORA research was supported within the Munich Center of Health Sciences (MC Health), Ludwig-Maximilians-Universität, as part of LMUinnovativ. J.L.G.-S. and F.C. acknowledge funding of the Spanish and the Andalusian Governments and the Feder program for grants (BFU2010-14839, BFU2009-07044, CSD2007-00008, and Proyectos de Excelencia CVI-3488 and CVI 2658). This work was funded in part by a grant from the German Federal Ministry of Education and Research (BMBF) to the German Center for Diabetes Research (DZD), to the German Mouse Clinic (Infrafrontier: 01KX1012), to the German Center for Neurodegenerative Diseases (DZNE), Germany; by the Initiative and Networking Fund of the Helmholtz Association in the framework of the Helmholtz Alliance for Mental Research in an Ageing Society (HA-215); and the Munich Cluster for Systems Neurology (EXC 1010 SyNergy) and its Collaborative Research Center (CRC) 870/2 “Assembly and Function of Neuronal Circuits.”Peer Reviewe
TEAD and YAP regulate the enhancer network of human embryonic pancreatic progenitors
PMCID: PMC4434585.-- et al.The genomic regulatory programmes that underlie human organogenesis are poorly understood. Pancreas development, in particular, has pivotal implications for pancreatic regeneration, cancer and diabetes. We have now characterized the regulatory landscape of embryonic multipotent progenitor cells that give rise to all pancreatic epithelial lineages. Using human embryonic pancreas and embryonic-stem-cell-derived progenitors we identify stage-specific transcripts and associated enhancers, many of which are co-occupied by transcription factors that are essential for pancreas development. We further show that TEAD1, a Hippo signalling effector, is an integral component of the transcription factor combinatorial code of pancreatic progenitor enhancers. TEAD and its coactivator YAP activate key pancreatic signalling mediators and transcription factors, and regulate the expansion of pancreatic progenitors. This work therefore uncovers a central role for TEAD and YAP as signal-responsive regulators of multipotent pancreatic progenitors, and provides a resource for the study of embryonic development of the human pancreas.The research was supported by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre. Work was funded by grants from the Ministerio de Economía y Competitividad (CB07/08/0021, SAF2011-27086, PLE2009-0162 to J.F., BFU2013-41322-P to J.L.G-S.), the Andalusian Government (BIO-396 to J.L.G-S.), the Wellcome Trust (WT088566 and WT097820 to N.A.H., WT101033 to J.F.), the Manchester Biomedical Research Centre, ERC advanced starting grant IMDs (C.H-H.C. and L.V.) and the Cambridge Hospitals National Institute for Health Research Biomedical Research Centre (L.V.). R.E.J. is a Medical Research Council clinical training fellow. The authors are grateful to C. Wright (Vanderbilt University) for zebrafish Pdx1 antiserum, J. Postlethwait (Purdue University) for a Sox9b clone, H. Sasaki (Kumamoto University) for a TEAD–EnR clone, C. Vinod and L. Abi for research nurse assistance, and clinical colleagues at Central Manchester University Hospitals NHS Foundation Trust. The authors thank J. Garcia-Hurtado for technical assistance (IDIBAPS).Peer Reviewe
meis1 regulates cyclin D1 and c-myc expression, and controls the proliferation of the multipotent cells in the early developing zebrafish eye
5 páginas, 4 figuras. Supplementary material for this article is available at http://dev.biologists.org/cgi/content/full/135/5/799/DC1During eye development, retinal progenitors are drawn from a multipotent, proliferative cell population. In Drosophila the maintenance of this cell population requires the function of the TALE-homeodomain transcription factor Hth, although its mechanisms of action are still unknown. Here we investigate whether members of the Meis gene family, the vertebrate homologs of hth, are also involved in early stages of eye development in the zebrafish. We show that meis1 is initially expressed throughout the eye primordium. Later, meis1 becomes repressed as neurogenesis is initiated, and its expression is confined to the ciliary margin, where the retinal stem population resides. Knocking down meis1 function through morpholino injection causes a delay in the G1-to-S phase transition of the eye cells, and results in severely reduced eyes. This role in cell cycle control is mediated by meis1 regulating cyclin D1 and c-myc transcription. The forced maintenance of meis1 expression in cell clones is incompatible with the normal differentiation of the meis1-expressing cells, which in turn tend to reside in undifferentiated regions of the retinal neuroepithelium, such as the ciliary margin. Together, these results implicate meis1 as a positive cell cycle regulator in early retinal cells, and provide evidence of an evolutionary conserved function for Hth/Meis genes in the maintenance of the proliferative, multipotent cell state during early eye development.This work was supported by grants BMC2003-06248 and BFU2006-00349/BMC from the Spanish Ministry of Education and Science, co-funded by FEDER, to F.C. J.B., M.J.T. and J.S. are supported by the Fundação para Ciência e Tecnologia, Portugal. The CABD is institutionally supported by Junta de Andalucía.Peer reviewe
Discrimination of meat produced by Bos taurus and Bos indicus finished under an intensive or extensive system
Research Areas: Agriculture ; Veterinary Sciences ; ZoologyMeat obtained under commercial conditions shows considerable variability, mostly due to genetic background and production system. In this study, meat physicochemical properties and fatty acid profiles were analysed to investigate the feasibility of using them as tools to discriminate between meats produced by different genetic groups and finishing systems. Samples of the Longissimus thoracis were collected from 160 commercial bulls of the B. taurus (n = 75) and B. indicus (n = 85) groups, finished either on pasture (n = 46) or with grain supplementation (n = 114) and analysed by standard procedures. Data were analysed by discriminant analysis using a stepwise procedure, to select the meat characteristics that better contribute to discriminate the various groups. Our results indicate that fatty acid profiles of meat had better discriminating ability than physicochemical properties, especially to identify meat from animals finished on grain or pasture. The overall discrimination of meat from different genetic groups was achieved with a slightly lower reliability. Nonetheless, our results show that reliability of allocation to genetic group can be improved if prior information on finishing system is considered. These results are of high importance because they can be incorporated as tools to assess the authenticity of beef, particularly in meat certification programs.info:eu-repo/semantics/publishedVersio
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