O papel evolutivo dos mecanismos epigenéticos: a adaptação de organismos dulçaquicolas às alterações climáticas

Mestrado em Biologia Molecular e CelularFreshwater is a precious resource for humankind. Nevertheless, freshwater systems face not only significant anthropogenic pressure but also numerous transformations induced by climate change. Nowadays, climate change is recognized as a serious threat to freshwater ecosystems and, on a global scale, freshwater biodiversity is in rapid decline. In the last few years, epigenetics has been gaining importance in several scientific fields, such as human health and developmental biology. In fact, epigenetic mechanisms can influence phenotype determination and epigenetically acquired phenotypes are known to be inherited across several generations. Therefore, epigenetics is a promising but unexplored topic in a significant number of scientific fields. Taking into account that the global aim of this work was to explore the resilience of freshwater species to cope with the environmental transformations induced by climate change, its main specific objectives were: i) to review the impacts of climate change on freshwater ecosystems, and explore the link between epigenetic mechanisms and the adaptation of different species to the associated phenomena; ii) to assess the relevance of epigenetic mechanisms in the adaptation of Daphnia magna to an increase in water salinity. An extensive review was made leading to the conclusion that climate change is transforming the composition, biodiversity and functioning of numerous freshwater ecosystems. Additionally, this study highlighted that, in the context of climate change, the rise in water temperature and/or salinity are the major threats to freshwater biodiversity, while epigenetic mechanisms can have a decisive role in constraining both short- and long-term adaptation of different taxonomic groups to the environmental transformations induced by climate change. As the second objective was tackled, the exposure of one generation of Daphnia magna to increased salinity showed that there is a molecular adaptation to the hyperosmotic environment at the epigenetic level. For some genes, this epigenetic adaptation was transferred across three successive generations, none of which exposed to the stressor challenging the parental generation. Generally, this work supports the idea that epigenetic mechanisms are a promising topic in the fields of aquatic toxicology and evolutionary biology, as well as in research undertaken in their intersection.A água doce é um dos recursos mais preciosos para a humanidade. No entanto, para além de serem alvo de significativas pressões antropogénicas, os sistemas dulçaquícolas enfrentam diversas transformações impostas pelas alterações climáticas. Em particular, as alterações climáticas são, hoje em dia, reconhecidas como uma ameaça séria para os ecossistemas dulçaquícolas, sendo que, à escala global, a biodiversidade de água doce está em rápido declínio. Nos últimos anos, a epigenética tem ganho importância em diversos campos científicos, como a saúde humana e a biologia do desenvolvimento. De facto, os mecanismos epigenéticos regulam o aparecimento de novos fenótipos, estando comprovado que os fenótipos determinados epigeneticamente podem ser transmitidos ao longo de sucessivas gerações. Assim, a epigenética é um tema promissor mas largamente inexplorado num grande número de áreas científicas. Procurando avaliar a resiliência das espécies dulçaquícolas para lidar com as transformações ambientais impostas pelas alterações climáticas, este trabalho teve como principais objetivos: i) rever os impactos das alterações climáticas nos ecossistemas dulçaquícolas, explorando a relação entre os mecanismos epigenéticos e a adaptação de diversos grupos de organismos a este fenómeno; ii) avaliar a potencial importância dos mecanismos epigenéticos na adaptação de Daphnia magna a um aumento na salinidade das águas. Uma extensa revisão da literatura foi efetuada, tendo sido concluído que as alterações climáticas estão a alterar a composição, biodiversidade e funcionamento dos ecossistemas dulçaquícolas. Adicionalmente, este trabalho evidenciou que, no contexto das alterações climáticas, o aumento da temperatura e/ou salinidade da água são as principais ameaças para a biodiversidade dulçaquícola, sendo que os mecanismos epigenéticos podem contribuir decisivamente para a adaptação de diferentes grupos taxonómicos, tanto a curto como a longo prazo, às flutuações e transformações ambientais provocadas pelas alterações climáticas. Na abordagem do segundo objetivo desta dissertação, a exposição de uma geração de Daphnia magna a um aumento de salinidade na água induziu uma adaptação molecular, ao nível epigenético, ao ambiente hipertónico. Para alguns genes, esta adaptação epigenética foi transferida ao longo de três sucessivas gerações, nenhuma das quais expostas ao agente de stress a que esteve exposta a geração parental. Globalmente, este trabalho suporta a ideia de que os mecanismos epigenéticos são um tema promissor nas áreas da ecotoxicologia aquática e biologia evolutiva, bem como na interface entre estas duas áreas de investigação

Transgenerational inheritance of DNA hypomethylation in Daphnia magna in response to salinity stress

Epigenetic mechanisms have been found to play important roles in environmental stress response and regulation. These can, theoretically, be transmitted to future unexposed generations, yet few studies have shown persisting stress-induced transgenerational effects, particularly in invertebrates. Here, we focus on the aquatic microcrustacean Daphnia, a parthenogenetic model species, and its response to salinity stress. Salinity is a serious threat to freshwater ecosystems and a relevant form of environmental perturbation affecting freshwater ecosystems. We exposed one generation of D. magna to high levels of salinity (F0) and found that the exposure provoked specific methylation patterns that were transferred to the three consequent nonexposed generations (F1, F2, and F3). This was the case for the hypomethylation of six protein-coding genes with important roles in the organisms' response to environmental change: DNA damage repair, cytoskeleton organization, and protein synthesis. This suggests that epigenetic changes in Daphnia are particularly targeted to genes involved in coping with general cellular stress responses. Our results highlight that epigenetic marks are affected by environmental stressors and can be transferred to subsequent unexposed generations. Epigenetic marks could therefore prove to be useful indicators of past or historic pollution in this parthenogenetic model system. Furthermore, no life history costs seem to be associated with the maintenance of hypomethylation across unexposed generations in Daphnia following a single stress exposure

Secular trend of sports practice of Brazilian children and young people in the decade of mega-sport events

Introduction: Hosting mega-sport events can be an important political strategy for promoting the sport. Brazil had a decade with different mega-sport events, so we want to highlight how many Brazilian young people have been practicing sports throughout this period. Methods: This secular trend was attended by over 37,000 young people during January 2007 and December 2018. This data is part of a project aimed at mapping physical fitness, growth indicators and sports practice of young Brazilians. Data were described using descriptive statistics techniques. Results: The girls' sport practice was always smaller than boys, despite the decrease in the practice of the boys in 2012. We note a substantial upsurge in the years before the Olympic Games. Especially in Brazil, the years before Rio's Olympic Games happened the men's soccer world cup and men's confederations cup. In this year’s we note a substantial upsurge in sports practice. However, soccer, futsal (boys) and volleyball (girls) are the most practiced sports. Implications: From these results, the strategies for promoting sports can be revaluated. Understanding which sports are the most and least practiced by children is a first step towards directing policies for the promotion and democratization of sports, regardless of the sport

Implicações tecnológicas no seio dos trabalhadores da Universidade 11 de Novembro diante das políticas de inovação

Exportado OPUSMade available in DSpace on 2019-08-14T08:39:51Z (GMT). No. of bitstreams: 2 capa_tese_jeremias_pdf.pdf: 172835 bytes, checksum: 4a7ef0fa791a997b0be896d5de2447f9 (MD5) tese_jeremias_pdf.pdf: 7191893 bytes, checksum: 24cd03730367d75f53ab30ac016b66f2 (MD5) Previous issue date: 21O ensino superior em Angola nos últimos anos foi caracterizado pelas novas políticas públicas com objetivo de conferir às universidades maior oferta de vagas e melhor qualidade na formação de técnicos superiores. Implementadas no âmbito, da reorganização do ensino superior, as políticas públicas de expansão, permitiram o surgimento de novas universidades públicas e privadas. As províncias Cabinda e Zaire, contemplam a região académica III sendo a Universidade 11 de Novembro a única instituição pública do ensino superior nesta circunscrição geográfica. A tese intitulada Implicações Tecnológicas no Seio dos Trabalhadores da Universidade 11 de Novembro Diante das Políticas de Inovação, tem como objetivo geral, avaliar o impacto das Tecnologias de Informação e Comunicação (TIC) no seio dos trabalhadores docentes, administrativos e investigadores da Universidade 11 de Novembro por intermédio dos seus discursos. Para alcançar o objetivo foi necessário proceder uma pesquisa bibliográfica da temática com principais conceitos sobre tecnologias e suas implicações, teorias de inovações, tecnologias no ensino, políticas públicas do ensino superior no contexto geral. Os objetivos específicos tiveram como pressupostos fazer abordagens sistemáticas sobre a dinâmica das políticas públicas do Ensino Superior em Angola no período da independência e o contexto da Universidade 11 de Novembro (UON) destacando o papel do executivo de Angola na definição e implementação das políticas de expansão do ensino superior no país, e o plano estratégico de formação de quadros superior na diáspora. A pesquisa revela também os principais fatores que influenciaram o processo de implementação das inovações tecnológicas e o seu impacto no seio dos trabalhadores docentes, administrativos e investigadores da UON. A pesquisa ocorreu entre 2012 e 2015 nos períodos antes, durante e depois da implementação das inovações em causa Para a coleta de dados recorremos à entrevista envolvendo trabalhadores docentes, administrativos e investigadores. A exploração descritiva fenomenológica foi o método selecionado coadjuvado pelas técnicas de observação intensiva e extensiva. A primeira, permitiu a aplicação da entrevista estruturada enquanto a segunda foi necessário o uso do questionário para a coleta de dados que depois da interpretação, conclui-se que os trabalhadores tiveram um posicionamento positivo pelas inovações decorrentes na instituição e a caracterização do grau de implicações pelas inovações é moderado mas acarretando consigo transformações que interferiram subjetiva e subjetivamente no ambiente laboral dos funcionários pela nova realidade, experiências e comportamentos, ao mesmo tempo que descartaram outras construídas historicamente por eles.Higher education in Angola in recent years was characterized by new public policies in order to give the universities greater openings and better quality in the training of senior technicians. Implemented as part of the reorganization of higher education, public policies of expansion, allowed the emergence of new public and private universities. The Cabinda and Zaire provinces include academic Region III and the University November 11 the only public institution of higher education in this geographical constituency. The thesis entitled "Technological Implications among the workers at the University November 11th on innovation policies", has the objective systematic approaches to the Information Technology and Communication and the dynamics of public policies of higher education in Angola. To achieve the goal it was necessary a bibliographical survey of the thematic main concepts of technology and its implications, innovation theories, technology in education, public policies of higher education in the overall context. The specific objectives were as systematic approaches make assumptions about the dynamics of public policies of higher education in Angola in the independence period and the context of the University November 11 (UON) highlighting the role of the executive Angola in the definition and implementation of expansion policies higher education in the country, and the strategic plan of higher abroad staff training. The survey also reveals the main factors that influenced the process of implementation of technological innovations and their impact within the faculty workers, administrative and researchers UON. The research took place between 2012 and 2015 in the periods before, during and after the implementation of innovations concerned, for data collection resorted to interview employees involving teachers, administrative and researchers. The dialectic was the method selected and assisted by intensive and extensive observation techniques. The first allowed the application of structured interview while the second was necessary to use the questionnaire to collect data after interpretation is concluded that workers had a positive attitude for innovation resulting in the institution and to characterize the degree of implications for innovation is moderate but causing changes that can interfere subjective and subjectively in the work environment of employees by the new reality, experiences and behaviors, while others dismissed built historically for the

DNA methylation biomarkers : new tools for the human health and environmental risk assessment of chemicals

Epigenetic mechanisms have gained relevance in the fields of human and environmental health, due to their pivotal role in disease, gene-environment interactions and adaptation to environmental change and/or contamination. Epigenetic mechanisms are highly responsive to external stimuli and a wide range of chemicals has been shown to determine specific epigenetic patterns in several organisms. Furthermore, the mitotic/meiotic inheritance of such epigenetic marks as well as their corresponding changes in gene expression and cell/organismal phenotypes has now been demonstrated. Therefore, epigenetic signatures are very interesting candidates to link environmental exposures to disease as well as they can inform on relevant past exposures to stressors. Accordingly, well developed epigenetic biomarkers can be useful tools in both prospective and retrospective environmental risk assessment (ERA) but their actual application in this context is still not effective due to several data gaps that exist. Here we show that the incorporation of epigenetic biomarkers in the prospective ERA of chemicals can allow a better characterization of hazard potential (exposure and effects), by providing a comprehensive view on the corresponding mode of action or mechanism of toxicity and eventually elucidating on exposure routes, globally contributing to the establishment of Adverse Outcome Pathways. Epigenetic biomarkers can also have an important role in retrospective assessment by allowing to better distinguish fluctuating or historical exposure, as well as providing insights on the resilience of natural populations. By bringing together the epigenetics field and ERA as a comprehensive framework to tackle contamination challenges, promising avenues are open for scientists and regulators

Epigenetic regulation : the cross-talk among development, adaptive strategies, and microevolutionary change

In this chapter, we aim to demonstrate that epigenetic regulation is a central, cohesive and comprehensive process that underpins, reflects in and brings together developmental aspects, phenotypic responses and inheritance that may constrain evolutionary pathways. In particular, evidence on the critical role of epigenetics in developmental biology was compiled, which demonstrates that, despite the stability of such processes, epigenetic mechanisms remain highly responsive to environmental cues, especially during the early stages of life. By exploring how epigenetic changes during development can have persistent effects, often impinging heredity and evolution, epigenetic inheritance is highlighted as the core of the cross-talk between early life, adulthood and transgenerational effects on phenotypes. Accordingly, we then discuss the role of epigenetic changes in shaping species’ adaptive strategies, as well as the role of epigenetic inheritance in defining actual adaptation, therefore highlighting the importance of epigenetic mechanisms and inheritance for evolutionary processes. Moreover, critical data gaps were pointed out throughout the different subjects addressed, thereby opening interesting avenues for epigenetic research on development, ecology, ecotoxicology and evolution