Exploring the evolutionary link between biofilms and spores formation in spore-formers

Bacteria are often thought as single cell organisms, however they can develop into morphologically complex multicellular communities composed of different subpopulations of specialized cell types. Biofilm is an example, in which bacteria organize for protection from harmful conditions in the host and to create nutrient-rich areas. In the last years biofilm have been show to comprise an important aspect of microbial persistence in the human gut. Endospore-formers, although thought not to be major constituents of the microbiota in the human intestine, cause several intestinal diseases, usually associated with antibiotic use. Whether these bacteria persist in the intestine in biofilms or as endospores is not totally elucidated since both, biofilms and endospores, are able to resist to antimicrobial agents. Most likely sporulation and biofilm formation are tightly linked processes. For some endosporeformers, spore differentiation is induced by a sub-population of cells within the biofilm. In this work we tackled the link between bacterial biofilms and endosporulation in Bacillus subtilis. We showed that endospores produced in biofilms have higher resistance to UV radiation. We revealed that a gene, remA, conserved among endosporeformers and essential for biofilm formation is expressed during sporulation. remA is expressed in the forespore soon after asymmetric division and in the mother cell after engulfment completion. GerE represses remA expression in the mother cell at late stages of sporulation. Consequently, we found components of the biofilm matrix, TasA and BslA, on the coat of endospores produced in biofilms. We suggest that components of the biofilm matrix may be part of mature endospores. We hypothesize that some of the structural proteins that confer integrity to the matrix biofilm, as TasA, may have a role as a scaffold for the assembly of the endospore surface layers.A percepção instalada é a de que as bactérias são organismos unicelulares. No entanto, estes organismos são capazes de se organizarem em comunidades multicelulares complexas compostas de subpopulações de células diferenciadas. Os biofilmes são um exemplo deste tipo de organização. Os biofilmes conferem protecção contra as condições desfavoráveis encontradas no hospedeiro, ao mesmo tempo que criam nichos ricos em nutrientes facilitando a implantação da população. Nos últimos anos foi demonstrado que a persistência microbiana no trato gastrointestinal humano se deve em larga medida à formação de biofilmes. Algumas bactérias que podem ser encontradas no trato gastrointestinal humano são ainda capazes de diferenciar um tipo celular altamente resistente a insultos químicos e físicos, o esporo. Nestes casos, não é claro se são os biofilmes ou os endoesporos os principais responsáveis pela persistência destes organismos, já que ambos são resistentes aos antibióticos. Neste trabalho exploramos a ligação genética entre a formação de biofilmes e a esporulação em Bacillus subtilis. Mostramos que os endoesporos produzidos em biofilmes exibem maior resistência aos UV. Mostramos que um gene, remA, conservado em bactérias formadoras de endoesporos e essencial para a formação de biofilmes é expresso durante a esporulação. remA é expresso no pré-esporo após a divisão assimétrica e na célula mãe após o envolvimento do pré-esporo. GerE reprime a expressão de remA na célula mãe em estádios tardios de desenvolvimento. Consequentemente, encontramos componentes da matriz do biofilme no manto de endoesporos maduros. Algumas das proteínas estruturais que conferem integridade à matriz do biofilme, como TasA, poderão servir como base para a montagem das camadas superficiais do esporo

The impact of private equity-backed firms on their peers

Reconhecendo a crescente importância do mercado de private equity, a presente tese tem como objectivo principal estudar a dimensão competitiva desta indústria. Recorrendo a amostras de empresas americanas e canadianas, pretende-se saber se as transacções em private equity têm algum impacte ao nível das concorrentes das empresas participadas. Em particular, considera-se a compensação total do CEO e analisa-se de forma independente cada uma das suas componentes, a fixa e a variável. A estrutura de capital e as características do Conselho de Administração são também alvo de estudo. De acordo com os resultados, a compensação total do CEO diminui perante a existência de investimentos em private equity na indústria. Analisando individualmente a componente fixa e a variável, conclui-se que, muito provavelmente, aquele decréscimo ocorre por via da parte variável da remuneração, já que esta, de acordo com os dados finais, é também reduzida. O salário não sofre alterações. Relativamente à estrutura de capital, identifica-se uma relação entre a ocorrência de investimentos em private equity e um maior nível de endividamento das concorrentes. Não existe evidência de que as variáveis do Conselho de Administração, isto é, a sua dimensão e estrutura, sejam afectadas pela presença de empresas participadas por private equity.Given the growing importance of the private equity market, in this thesis we study the competitive dimension of this industry. By using samples of American and Canadian companies we analyse whether private equity transactions have any effect on the competitors of the invested companies. In particular, we consider the total CEO compensation and its fixed and variable components. We are also interested in the capital structure and in board variables. We provide evidence supporting a reduction in the total CEO compensation of competitors when an investment in private equity occurs. In order to better understand this result we run the model with the fixed component and the variable one. We then show that the variable compensation is very likely the main responsible for that reduction. Concerning the capital structure, the findings suggest an association between private equity transactions and a higher debt level of competitors. According to the results, the board variables, which consist of the size and the structure of the board of directors, are not affected by the presence of private equity investments

Exploring deregulated signals involved in motor neuron-microglia cross-talk in ALS

Part of the results discussed in this thesis was presented in the following meetings: Cunha MI, Cunha C, Vaz AR, Brites D. Studying microglial-motoneuron cross-talk in ALS pathology. 6th iMed.UL Postgraduate Students Meeting, Lisbon, July 2, 2014. [Abstract and Poster] Vaz AR. Motoneuron degeneration and glial reactivity in ALS: insights from cellular to animal models. Neuroscience Seminars at IMM 2012, Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal, June 9, 2014. [Oral Communication (by invitation)]Amyotrophic Lateral Sclerosis (ALS) is the most common neurodegenerative disease affecting motor neurons (MNs). Neuroinflammation has shown to be a prominent pathological feature, highlighted by the presence of activated microglia, which may exert either beneficial or detrimental effects. Mutated MNs may release factors able to induce different microglial responses. However, how cells differently modulate each other remains elusive. Therefore, a better understanding of the MN-microglia signaling pathways compromised in ALS is warranted. Here, we aim (i) to uncover signaling pathways underlying MN injury and (ii) to dissect how MNs are modulating microglial response as well as the contribution of healthy microglia to rescue MN dysfunction. We focused on fractalkine-CX3XR1 axis, MFG-E8-mediated phagocytosis and HMGB1-TLR4 signaling. For this we used a MN-like cell line (NSC-34) stably transfected with human SOD1, either wild-type (wtMNs) or with G93A mutation (mMNs), alone or in mixed cultures with N9 microglial cell line. We observed a compromised viability of microglia in the presence of mMNs, yet they were more activated, as suggested by the increase of CD11b mRNA expression. The dysfunctional mechanisms associated with increased NO and decreased glutamate production by mMNs were not recovered by the presence of healthy microglia. However, the increased activity of matrix metalloproteinase -9 observed in mMNs was decreased in the presence of microglia. In addition, mMNs presented accumulation of membrane-fractalkine and, in mixed cultures, CX3CR1 mRNA expression was up-regulated in their presence. Furthermore, we showed that mMNs expressed higher levels of MFG-E8, which were further increased in the presence of microglia. Finally, both HMGB1 and TLR4 levels were also increased in mMNs, mainly in the presence of microglia. Together, these results highlight an impairment of microglial function caused by MN dysfunction and support the development of immunomodulatory strategies restoring both healthy state of microglia and MNs

Revisiting small and medium-sized enterprises' innovation and resilience during COVID-19: the tourism sector

Every day, companies are exposed to various risks arising from their environment, and Small and Medium Enterprises (SMEs) are the most affected. This study emphasizes innovation and resilience as the starting points to understand how they are influenced by external factors which are independent of the managers' will. To date, we have seen several extreme factors that have conditioned businesses and entrepreneurs of this type of companies, such as the Financial Crisis of 2008. However, last year we saw the beginning of a Worldwide Pandemic: COVID-19 Pandemic. Thus, this research seeks to understand the extent to which this pandemic influenced the resilience and innovation of SMEs in the Tourism area. Thus, eight hypotheses were raised based on four independent variables: Access to Finance, Risk Taking, Working Conditions, and Personal Network. The study of these variables was developed from an online questionnaire and in-depth interviews. After analyzing the results, it is possible to infer that the COVID-19 Pandemic resulted in consequences never observed in previous crises, to such an extent that the study showed that: 1) a company's Network positively influence its resilience; 2) Risk-Taking influences innovation and resilience of these SMEs.Diariamente, as empresas estão expostas a vários riscos provenientes do ambiente onde estão inseridas, sendo as Pequenas e Médias Empresas (PMEs) as mais afetadas. Este estudo enfatiza a inovação e a resiliência como os pontos de partida para perceber de que maneira são estas influenciadas por fatores externos e independentes da vontade dos gestores. Até hoje, assistimos a vários fatores extremos que condicionaram negócios e empresários deste tipo de empresas, como por exemplo a Crise Financeira de 2008. Contudo, no final de 2019 observámos o início de uma Pandemia Mundial - COVID-19, cujas consequências se fizeram sentir a partir de 2020. Desta forma, esta investigação procura compreender em que medida esta pandemia influenciou a resiliência e a inovação das PME na área do Turismo. Desta forma, foram levantadas oito hipóteses com base em quatro variáveis independentes: "Access to Finance", "Risk Taking", "Working Conditions" e "Personal Network". O estudo destas variáveis foi desenvolvido a partir de um questionário "online" e de entrevistas em profundidade. Após a análise dos resultados, é possível inferir que a Pandemia da COVID-19 resultou em consequências nunca observadas em crises anteriores, pelo que o estudo mostrou que: 1) as "Personal Network" de uma empresa influenciam positivamente a sua resiliência; 2) "Risk Taking" influencia a inovação e a resiliência destas PMEs

The efficacy of 1-day soft skills training on master students’ performance

JEL Classification System: M5 Personnel Economics M53 Training O1 Economic Development O15 Human Resources; Human Development; Income Distribution; MigrationNowadays, the student‟s academic performance is based not only on hard skills, but also on soft skills which became more and more important during the last years. Due to the frequent changes in the market, companies look for employees that give them advantage over the competition and interpersonal skills have been highly valorized. This study aims at proving the importance of soft skills trainings in the academic context and foster future implementations of it. This research analyses the efficacy of 1-day training for developing master students‟ soft skills on teamwork and conflict management skills. The efficacy of the training was analysed according to the four levels of the Kirkpatrick training evaluation model, namely reaction, learning, behaviour and results. The benefits were considered in terms of development of teamwork and conflict management skills, as well as greater students‟ performance. It was assessed through online surveys regarding these skills and students were asked to fill at different moments, during the first semester. The results show that the reaction level was considered effective and participants referred very high levels of satisfaction. The learning level was also effective considering the teamwork skills, however it did not show positive results regarding the cognitive learning of conflict management. The results did not provide conclusions that this training intervention was effective at the behaviour and results levels. Nevertheless, the research contributed as an evaluation of the training intervention and as a demonstration of the utility of the Kirkpatrick‟s training evaluation model.Hoje em dia, o desempenho académico dos estudantes é baseado não só em hard skills, mas também em soft skills, que se tornaram cada vez mais importantes nos últimos anos. Devido às frequentes mudanças no mercado, as empresas procuram colaboradores que lhes permitam obter vantagem sobre a concorrência. Neste sentido, os soft skills têm sido altamente valorizados. Este estudo tem como objetivo provar a importância da formação em soft skills no contexto académico e fomentar a organização destas iniciativas. Esta pesquisa analisa a eficácia de uma formação de um dia, no desenvolvimento de soft skills dos estudantes de mestrado, especificamente trabalho em equipa e gestão de conflitos. A eficácia da formação foi analisada através do modelo de avaliação de formação de Kirkpatrick, observaram-se os quatro níveis: reações, aprendizagem, comportamentos e resultados. Os benefícios foram considerados em termos de desenvolvimento de competências de trabalho em equipa e gestão de conflitos, bem como o aumento do desempenho dos estudantes. Os alunos preencheram questionários online sobre as referidas competências, em diferentes momentos, durante o primeiro semestre. Os resultados mostram que o nível de reações foi considerado eficaz, assim como o nível de aprendizagem relativamente às competências de trabalho em equipa. No entanto, não foram apresentados resultados positivos relativos à aprendizagem cognitiva de gestão de conflitos. Este estudo revela que a formação não foi eficaz nos dois últimos níveis de avaliação: comportamentos e resultados. No entanto, a pesquisa contribuiu como avaliação da formação e demonstração da utilidade do modelo de avaliação de Kirkpatrick

Credit risk stress testing: the Portuguese environment, macroeconomic scenarios and the estimation of losses for corporate sectors

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and EconomicsThis study focuses on the development of a macroeconomic credit risk model for the prediction of corporate default rates, conditional on the observed economic environment. Data relative to the Portuguese economy was utilized for the development of the model, regarding the period from 2002 to 2012. The results suggest a clear link between macroeconomic factors, such as GDP, interest rates, unemployment and corporate indebtness, to the default rates observed. Furthermore, the introduction of a Merton-based analysis of the loss distributions permitted the analysis of expected and unexpected losses, alongside Basel II capital requirement evolutions