31 research outputs found

    Drosophila protein kinase N (Pkn) is a negative regulator of actin-myosin activity during oogenesis

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    Nurse cell dumping is an actin-myosin based process, where 15 nurse cells of a given egg chamber contract and transfer their cytoplasmic content through the ring canals into the growing oocyte. We isolated two mutant alleles of protein kinase N (pkn) and showed that Pkn negatively-regulates activation of the actin-myosin cytoskeleton during the onset of dumping. Using live-cell imaging analysis we observed that nurse cell dumping rates sharply increase during the onset of fast dumping. Such rate increase was severely impaired in pkn mutant nurse cells due to excessive nurse cell actin-myosin activity and/or loss of tissue integrity. Our work demonstrates that the transition between slow and fast dumping is a discrete event, with at least a five to six-fold dumping rate increase. We show that Pkn negatively regulates nurse cell actin-myosin activity. This is likely to be important for directional cytoplasmic flow. We propose Pim provides a negative feedback loop to help avoid excessive contractility after local activation of Rho GTPase. (C) 2014 Elsevier Inc. All rights reserved.National Portuguese Funding through Grants FCT-Fundacao para Ciencia e Tecnologia [PTDC/SAU-BID/111796/2009, PTDC/BIA-BCM/111822/2009, PTDC/BBB-BQB/0712/2012, PEst-OE/EQB/LA0023/2013]; Fundacao para Ciencia e Tecnologia [SFRH/BD/37587/2007]info:eu-repo/semantics/publishedVersio

    Dificuldades de tradução Inglês-Português : um caso prático

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    Relatório de Estágio apresentado para cumprimento dos requisitos necessários à obtenção do grau de Mestre em TraduçãoO relatório procura descrever a actividade e competência tradutórias recorrendo aos conceitos de «dificuldades de tradução», «operações de tradução» e «análise de texto de relevância tradutória» desenvolvidos por Ana Maria Bernardo, Vinay e Darbelnet e Christiane Nord, respectivamente. O trabalho, de natureza teórico-prática, foca o nosso estágio de 400 horas na Eurologos-Lisboa, em que traduzimos um manual da ONU que visa apoiar os profissionais de justiça penal que trabalham na área do tráfico de seres humanos e imigração ilegal

    Transcription and splicing dynamics during early Drosophila development

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    © 2022 Prudêncio et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society. This article, published in RNA, is available under a Creative Commons License (Attribution 4.0 International), as described at http://creativecommons.org/licenses/by/4.0/.Widespread cotranscriptional splicing has been demonstrated from yeast to human. However, most studies to date addressing the kinetics of splicing relative to transcription used either Saccharomyces cerevisiae or metazoan cultured cell lines. Here, we adapted native elongating transcript sequencing technology (NET-seq) to measure cotranscriptional splicing dynamics during the early developmental stages of Drosophila melanogaster embryos. Our results reveal the position of RNA polymerase II (Pol II) when both canonical and recursive splicing occur. We found heterogeneity in splicing dynamics, with some RNAs spliced immediately after intron transcription, whereas for other transcripts no splicing was observed over the first 100 nt of the downstream exon. Introns that show splicing completion before Pol II has reached the end of the downstream exon are necessarily intron-defined. We studied the splicing dynamics of both nascent pre-mRNAs transcribed in the early embryo, which have few and short introns, as well as pre-mRNAs transcribed later in embryonic development, which contain multiple long introns. As expected, we found a relationship between the proportion of spliced reads and intron size. However, intron definition was observed at all intron sizes. We further observed that genes transcribed in the early embryo tend to be isolated in the genome whereas genes transcribed later are often overlapped by a neighboring convergent gene. In isolated genes, transcription termination occurred soon after the polyadenylation site, while in overlapped genes, Pol II persisted associated with the DNA template after cleavage and polyadenylation of the nascent transcript. Taken together, our data unravel novel dynamic features of Pol II transcription and splicing in the developing Drosophila embryo.This work was supported by funding to M.C.-F. (Fundação para a Ciência e Tecnologia, FCT/Ministério da Ciência, Tecnologia e Ensino Superior - Fundos do Orçamento de Estado [UIDB/50005/2020], and FCT/ FEDER/POR Lisboa 2020, Programa Operacional Regional de Lisboa PORTUGAL 2020, grant LISBOA-01-0145-FEDER-016394) and to R.G.M (FCT grant PTDC/BIA-BID/28441/2017). P.P. was a recipient of an FCT fellowship (SFRH/BD/109689/2015). R.S. was a recipient of an EMBO Long-Term Fellowship (EMBO ALTF 101-2019). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements no. 842695 (Marie Skłodowska- Curie Actions) and no. 857119 (RiboMed)info:eu-repo/semantics/publishedVersio

    Requirement for highly efficient pre-mRNA splicing during Drosophila early embryonic development

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    Drosophila syncytial nuclear divisions limit transcription unit size of early zygotic genes. As mitosis inhibits not only transcription, but also pre-mRNA splicing, we reasoned that constraints on splicing were likely to exist in the early embryo, being splicing avoidance a possible explanation why most early zygotic genes are intronless. We isolated two mutant alleles for a subunit of the NTC/Prp19 complexes, which specifically impaired pre-mRNA splicing of early zygotic but not maternally encoded transcripts. We hypothesized that the requirements for pre-mRNA splicing efficiency were likely to vary during development. Ectopic maternal expression of an early zygotic pre-mRNA was sufficient to suppress its splicing defects in the mutant background. Furthermore, a small early zygotic transcript with multiple introns was poorly spliced in wild-type embryos. Our findings demonstrate for the first time the existence of a developmental pre-requisite for highly efficient splicing during Drosophila early embryonic development and suggest in highly proliferative tissues a need for coordination between cell cycle and gene architecture to ensure correct gene expression and avoid abnormally processed transcripts.FCT-Fundacao para a Ciencia e Tecnologia (Portugal) [PTDC/SAU-BID/111796/2009, PTDC/BIA-BCM/111822/ 2009, PTDC/BBB-BQB/0712/2012, PEst-OE/EQB/LA0023/2013, SFRH/BPD/47957/2008, SFRH/BPD/63869/2009]info:eu-repo/semantics/publishedVersio

    Cutting Forces Assessment in CNC Machining Processes: A Critical Review

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    Machining processes remain an unavoidable technique in the production of high-precision parts. Tool behavior is of the utmost importance in machining productivity and costs. Tool performance can be assessed by the roughness left on the machined surfaces, as well as of the forces developed during the process. There are various techniques to determine these cutting forces, such as cutting force prediction or measurement, using dynamometers and other sensor systems. This technique has often been used by numerous researchers in this area. This paper aims to give a review of the different techniques and devices for measuring the forces developed for machining processes, allowing a quick perception of the advantages and limitations of each technique, through the literature research carried out, using recently published worksThe present work was done and funded under the scope of the project ON-SURF (ANI | P2020 | POCI-01-0247-FEDER-024521, co-funded by Portugal 2020 and FEDER, through COMPETE 2020-Operational Programme for Competitiveness and Internationalisation. F.J.G. Silva also thanks INEGI-Instituto de Ciência e Inovação em Engenharia Mecânica e Engenharia Industria, due to its support.info:eu-repo/semantics/publishedVersio

    Body composition, strength static and isokinetic, and bone health: comparative study between active adults and amateur soccer players

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    The Centro de Investigação do Desporto e Actividade Física (Research Unit for the Study of Sport and Physical Activity, uid/dtp/04213/2019) is being funded by Fundação para a Ciência e a Tecnologia. AOW is supported by São Paulo Research Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) process: 2017/27234-2.Objective: To compare tissue composition, total and regional bone mineral content and bone mineral density, static hand grip and knee joint isokinetic strength between amateur soccer players and Control Group. Methods: Cross-sectional study. Air displacement plethysmography was used to estimate body volume and, in turn, density. Body composition, bone mineral content and bone mineral density were assessed for the whole body and at standardized regions using dual energy X-ray absorptiometry. Static grip strength was assessed with an adjustable dynamometer, and peak torque derived from isokinetic strength dynamometer (concentric muscular knee actions at 60°/s). Magnitude of the differences between groups was examined using d-Cohen. Results: Compared to healthy active adults, soccer players showed larger values of whole body bone mineral content (+651g; d=1.60; p<0.01). In addition, differences between groups were large for whole body bone mineral density (d=1.20 to 1.90; p<0.01): lumbar spine, i.e. L1-L4 (+19.4%), upper limbs (+8.6%) and lower limbs (+16.8%). Soccer players attained larger mean values in strength test given by static hand grip protocol (+5.6kg, d=0.99; p<0.01). Conclusion: Soccer adequately regulates body composition and is associated better bone health parameters (bone mineral content and density at whole-body and at particular sites exposed to mechanical loadings).Objetivo: Comparar a composição de tecidos, o conteúdo mineral ósseo e a densidade mineral óssea totais e por regiões do corpo, a força de preensão manual estática, e força isocinética da articulação do joelho, entre um grupo de jogadores de futebol amadores e um Grupo Controle. Métodos: Estudo transversal utilizando pletismografia de ar deslocado para estimar o volume corporal, para subsequente cálculo da densidade corporal. A composição de tecidos, o conteúdo mineral ósseo e a densidade mineral óssea foram avaliados para o corpo todo e regiões padronizadas através da absorciometria de raios-X de dupla energia. A força de preensão manual estática foi avaliada por um dinamômetro ajustável. Os momentos máximos de força das ações musculares concêntricas para os extensores e flexores do joelho foram avaliados pela dinamometria isocinética (60°/s). Foi calculado o valor d-Cohen para apreciar a magnitude do efeito das diferenças entre grupos. Resultados: Os futebolistas apresentaram níveis superiores de conteúdo mineral ósseo em comparação com os adultos ativos do Grupo Controle (+651g; d=1,60; p<0,01) e obtiveram valores superiores de densidade mineral óssea (d: 1,20 a 1,90; p<0,01) para a coluna lombar, L1-L4 (+19,4%), membros superiores (+8,6%) e membros inferiores (+16,8%). Para a força de preensão (estática) a diferença foi moderada (d=0,99; p<0,01) com valores mais elevados apresentados pelo futebolistas (+5,6kg; d=0,99; p<0,01). Conclusão: A prática de futebol promove uma regulação adequada da composição corporal (tecidos magro e gordo) e ganhos na densidade mineral óssea, mais acentuada em partes do corpo com maior exposição aos impactos mecânicos da atividade motora.info:eu-repo/semantics/publishedVersio

    Morte fetal - a urgência da observação psiquiátrica: Fetal death - the urgency of psychiatric observation

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    Introdução: A morte fetal é um acontecimento único porque envolve simultaneamente nascimento e morte, representando um acontecimento traumático e extremamente doloroso para a maioria dos pais1,2. Em obstetrícia, morte fetal corresponde à morte do feto com idade gestacional igual ou superior a 20 semanas de gestação, uma morte que ocorre antes ou durante o parto3,4,5,6,7. Estas perdas estão associadas a custos psicológicos e sociais substanciais, diretos e indiretos, na mulher, família, profissionais de saúde e sociedade1,8,9,10. Sendo situações de crise que, na maioria dos casos, desorganizam a estrutura interna dos envolvidos e desencadeiam intensa dor e sofrimento5,8,9,11,12,13.Os objetivos deste trabalho são reconhecer as características do luto perante a morte fetal e quais as intervenções que se mostraram efetivas na elaboração do luto, prevenindo complicações na saúde mental.Metodologia: Revisão não sistemática da literatura.Resultados: As reações do luto devem ser interpretadas individualmente, pois são determinadas de modo pessoal, subjetivo e de forma contextual por quem a vivencia além disso, são influenciadas por diversos fatores, como as circunstâncias da morte e outras experiências semelhantes no passado4,6,9,14. O apoio ao casal deve incluir suporte e validação emocional bem como comunicação clara da informação4,12.Conclusões: O luto fetal é um processo global, complexo e multifacetado3. É fundamental que os cuidados de saúde materna sejam prestados por uma equipa multidisciplinar, com o objetivo de diminuir o sofrimento vivido pelo casal e prevenir situações que possam levar à perpetuação do sofrimento psíquico e/ou desencadear quadros patológicos15. Reconstruir a vida sem o seu filho é uma das mais dantescas tarefas da morte fetal e, contudo, no meio deste processo, o crescimento pessoal pode acontecer4

    Mutations at the flavin binding site of ETF:QO yield a MADD-like severe phenotype in Drosophila

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    Following a screening on EMS-induced Drosophila mutants defective for formation and morphogenesis of epithelial cells, we have identified three lethal mutants defective for the production of embryonic cuticle. The mutants are allelic to the CG12140 gene, the fly homologue of electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO). In humans, inherited defects in this inner membrane protein account for multiple acyl-CoA dehydrogenase deficiency (MADD), a metabolic disease of beta-oxidation, with a broad range of clinical phenotypes, varying from embryonic lethal to mild forms. The three mutant alleles carried distinct missense mutations in ETF:QO (G65E, A68V and S104F) and maternal mutant embryos for ETF:QO showed lethal morphogenetic defects and a significant induction of apoptosis following germ-band elongation. This phenotype is accompanied by an embryonic accumulation of short- and medium-chain acylcarnitines (C4. C8 and 02) as well as long-chain acylcarnitines (C14 and C16:1), whose elevation is also found in severe MADD forms in humans under intense metabolic decompensation. In agreement the ETF:QO activity in the mutant embryos is markedly decreased in relation to wild type activity. Amino acid sequence analysis and structural mapping into a molecular model of ETF:QO show that all mutations map at FAD interacting residues, two of which at the nucleotide-binding Rossmann fold. This structural domain is composed by a beta-strand connected by a short loop to an alpha-helix, and its perturbation results in impaired cofactor association via structural destabilisation and consequently enzymatic inactivation. This work thus pinpoints the molecular origins of a severe MADD-like phenotype in the fruit fly and establishes the proof of concept concerning the suitability of this organism as,a potential model organism for MADD. (C) 2012 Elsevier B.V. All rights reserved.Fundacao para a Ciencia e Tecnologia (FCT/MCTES, Portugal) [PTDC/SAU-GMG/70033/2006, PTDC/QUI-BIQ/113027/2009, PTDC/BIA-BCM/111822/2009, PTDC/SAU-BID/111796/2009, SFRH/BPD/41609/2007, SFRH/BPD/74475/2010, SFRH/BPD/34763/2007]; CLIMB UK; [PEst-OE/EQB/LA0004/2011]info:eu-repo/semantics/publishedVersio
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