Síntese proteica em espermatozoides de mamífero

Reversible protein phosphorylation is the key general mechanism for regulating vital sperm cells functions since sperm cells are highly compartmentalized and almost devoid of transcription and translation. However, there is a small area of uncondensed chromatin where transcription and translation are still possible. There is only one study in the literature showing protein synthesis occurs in spermatozoa during capacitation. The main goal of this work was to study if protein translation occurs, both in human and bovine spermatozoa. In order to achieve that, we monitored protein synthesis using the Surface Sensing of Translation (SUnSET) technique, followed by flow cytometry. The results revealed mRNA translation in spermatozoa. Furthermore, we analysed the impact of translation inhibition by mitochondrial and cytoplasmic ribosomes in the expression levels of diverse spermatozoa proteins. The results show that, while some proteins are affected by translation inhibitors, others remain stable. To conclude, our results support protein synthesis occurs in spermatozoa and show, for the first time, SUnSET technique allows to monitor and quantify the global protein synthesis in mammalian spermatozoa.A fosforilação proteica reversível é o principal mecanismo que regula as funções vitais dos espermatozóides, uma vez que, os espermatozóides são altamente compartimentados e praticamente desprovidos de transcrição e tradução. No entanto, existe uma pequena área de cromatina descondensada, na qual a transcrição e tradução ainda são possíveis. Existe apenas um estudo na literatura a demonstrar que ocorre síntese proteica nos espermatozóides durante a capacitação. O principal objetivo deste trabalho foi avaliar se a síntese proteica ocorre em espermatozoides de bovino e de humano. Deste modo, monitorizámos a síntese proteica, utilizando a técnica Surface Sensing of Translation (SUnSET), seguida de citometria de fluxo. Os resultados revelaram tradução de mRNA nos espermatozóides. Para além disso, avaliamos o impacto da inibição da tradução pelos ribossomas mitocondriais e citoplasmáticos nos níveis de expressão de diversas proteínas do espermatozoide. Os resultados demonstraram que, enquanto algumas proteínas são afetadas pelos inibidores da tradução, outras mantêm-se estáveis. Concluindo, os nossos resultados suportam que ocorre síntese proteica nos espermatozoides e demonstram, pela primeira vez, que a técnica SUnSET permite monitorizar e quantificar a síntese global de proteínas em espermatozoides de mamíferos.Mestrado em Biomedicina Molecula

The function of the TGF-beta and Toll signalling pathways in Tribolium dorsoventral patterning

Dorsoventral (DV) patterning in Drosophila melanogaster is one of the most well-known gene regulatory networks (GRN) in biology. To investigate if this GRN is conserved during insect evolution, functional analysis of TGF-beta and Toll pathways in the short-germ beetle Tribolium castaneum was performed. In the first part, the function of several BMP/Dpp extracellular modulators, including the products of Tolloid (Tld) and Twisted-gastrulation/Crossveinless (Tsg-Cv), was investigated in Tribolium via parental RNAi (pRNAi). While Tc-tld pRNAi knock-down decreases embryonic BMP activity, Tc-tsg(cv) knock-down completely abolishes it. These observations are strikingly different from those in Drosophila, where tsg is only required for a subset of Dpp activity. These results suggest that Tsg/Cv-like proteins are essential for BMP signalling in Tribolium. Since duplicated copies of tsg(cv)- and tld-related genes are present in the Drosophila melanogaster genome, duplication followed by sub-functionalization of these modulators might have changed the BMP/Dpp gradient during evolution of the dipteran Drosophila lineage. In the second part, a functional analysis of the Toll pathway was performed. This analysis addressed the question of why the Tribolium Dorsal nuclear gradient is not stable, but rapidly shrinks and disappears, in contrast to the stable Drosophila gradient. Negative feedback accounts for this dynamic behavior: Tc-Dorsal and one of its target genes (Tc-Twist) activate transcription of the I-KappaB homolog Tc-cactus, which in turn terminates Dorsal function. Despite its transient role, Tc-Dorsal is strictly required to initiate DV polarity, as in Drosophila. However, unlike Drosophila, embryos lacking Tc-Dorsal display a periodic pattern of DV cell fates along the AP axis, indicating that a self-organizing ectodermal patterning system operates independently of mesoderm or maternal DV polarity cues. The presence of self-organizing patterning systems in short-germ insects like Tribolium is in agreement with a regulative type of embryogenesis proposed by classical fragmentation studies on hemimetabolous insects. These results also elucidate how extraembryonic tissues are organized in short-germ embryos, and how patterning information is transmitted from the early embryo to the growth zone. Altogether, the functional analysis of the TGF-betA and Toll pathways in Tribolium dorsoventral patterning suggests that extensive changes in this GRN have occurred during insect evolution

VANTAGENS DO PREGÃO ELETRÔNICO NO SETOR PÚBLICO

Aborda-se nesta pesquisa o tema licitação delimitado para vantagens do pregão eletrônico no setor público. Tem-se como objetivo descrever as vantagens que a modalidade de licitação, pregão eletrônico, apresenta para administração pública. Justifica-se a pesquisa deste tema ao fato de que há vantagens na realização do pregão eletrônico para administração pública. Para tanto, usou-se de metodologia científica, com métodos adequados, no desenvolvimento deste estudo. Pelas caracterísitcas da pesquisa, utilizou-se o método qualitativo de análise com abordagem dedutiva, através de uma pesquisa téorica e bibliográfica. O resultado desta pesquisa evidenciou várias vantagens da modalidade de licitação/pregão eletônico, prevista na Lei 8.666/93. Estas vantagens foram agrupadas em três categorias marcantes, as quais agruparam todas as vantagens evidenciadas na pesquisa. São elas: a) Potencial incremento das vantagens econômicas em favor da administração pública; b) Ampliação do universo de fornecedores; e, c) Simplificação dos procedimentos licitatórios. As vantagens do pregão eletrônico, notadamente, explicam a sua rápida adoção por parte da Administração Pública, bem como a sua boa receptividade junto ao mercado fornecedor

phpSAFE: A Security Analysis Tool for OOP Web Application Plugins

There is nowadays an increasing pressure to develop complex web applications at a fast pace. The vast majority is built using frameworks based on third-party server-side plugins that allow developers to easily add new features. However, as many plugin developers have limited programming skills, there is a spread of security vulnerabilities related to their use. Best practices advise the use of systematic code review for assure security, but free tools do not support OOP, which is how most web applications are currently developed. To address this problem we propose phpSAFE, a static code analyzer that identifies vulnerabilities in PHP plugins developed using OOP. We evaluate phpSAFE against two well-known tools using 35 plugins for a widely used CMS. Results show that phpSAFE clearly outperforms other tools, and that plugins are being shipped with a considerable number of vulnerabilities, which tends to increase over time.PEst-OE/EGE/UI4056/201

Endoscopic diagnosis of an intramural hematoma presenting as an anticoagulant ileus

info:eu-repo/semantics/publishedVersio

The role of inequality in explaining the secular stagnation hypothesis

This paper focuses on one of the factors that have been put forward in the literature within the secular stagnation view: Rising inequality. In a two-step procedure, this research first applies the Laubach and Williams (2003) methodology to jointly estimate the natural rate of interest (NRI), potential output and its growth rate for the G7 and we find that the NRI has been decreasing in all countries, which is in accordance with the secular stagnation hypothesis. In a second step, a fixed effects regression for a panel of 7 countries is used to estimate the effect of inequality on the natural rate of interest from 1980 to 2016. We find evidence that rising inequality has contributed to the decline of the time-varying natural rate of interest