Browsing by Issue Date, starting with "2018-04"
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- Regulation of bicarbonate secretion in marine fish intestine by the calcium-sensing receptorPublication . Gregorio, Silvia; Fuentes, JuanIn marine fish, high epithelial intestinal HCO3- secretion generates luminal carbonate precipitates of divalent cations that play a key role in water and ion homeostasis. The present study was designed to expose the putative role for calcium and the calcium-sensing receptor (CaSR) in the regulation of HCO3- secretion in the intestine of the sea bream (Sparus aurata L.). Effects on the expression of the CaSR in the intestine were evaluated by qPCR and an increase was observed in the anterior intestine in fed fish compared with unfed fish and with different regions of intestine. CaSR expression reflected intestinal fluid calcium concentration. In addition, anterior intestine tissue was mounted in Ussing chambers to test the putative regulation of HCO3- secretion in vitro using the anterior intestine. HCO3- secretion was sensitive to varying calcium levels in luminal saline and to calcimimetic compounds known to activate/block the CaSR i.e., R 568 and NPS-2143. Subsequent experiments were performed in intestinal sacs to measure water absorption and the sensitivity of water absorption to varying luminal levels of calcium and calcimimetics were exposed as well. It appears, that CaSR mediates HCO3- secretion and water absorption in marine fish as shown by responsiveness to calcium levels and calcimimetic compounds.
- Computational modeling of In vitro swelling of mitochondria: A biophysical approachPublication . Makarov, Vladimir I.; Khmelinskii, Igor; Javadov, SabzaliSwelling of mitochondria plays an important role in the pathogenesis of human diseases by stimulating mitochondria-mediated cell death through apoptosis, necrosis, and autophagy. Changes in the permeability of the inner mitochondrial membrane (IMM) of ions and other substances induce an increase in the colloid osmotic pressure, leading to matrix swelling. Modeling of mitochondrial swelling is important for simulation and prediction of in vivo events in the cell during oxidative and energy stress. In the present study, we developed a computational model that describes the mechanism of mitochondrial swelling based on osmosis, the rigidity of the IMM, and dynamics of ionic/neutral species. The model describes a new biophysical approach to swelling dynamics, where osmotic pressure created in the matrix is compensated for by the rigidity of the IMM, i.e., osmotic pressure induces membrane deformation, which compensates for the osmotic pressure effect. Thus, the effect is linear and reversible at small membrane deformations, allowing the membrane to restore its normal form. On the other hand, the membrane rigidity drops to zero at large deformations, and the swelling becomes irreversible. As a result, an increased number of dysfunctional mitochondria can activate mitophagy and initiate cell death. Numerical modeling analysis produced results that reasonably describe the experimental data reported earlier.
- Editorial: ulcerative colitis submucosal fibrosis and inflammation: more than just stricturesPublication . Magro, F.; Sousa, H. T.
- Persistence of the ABCC6 genes and the emergence of the bony skeleton in vertebratesPublication . Parreira, Bruna; Cardoso, João; Costa, Rita; Couto, Ana Rita; Bruges-Armas, Jacome; Power, Deborah M.The ATP-binding cassette transporter 6 (ABCC6) gene encodes a cellular transmembrane protein transporter (MRP6) that is involved in the regulation of tissue calcification in mammals. Mutations in ABCC6 are associated with human ectopic calcification disorders. To gain insight into its evolution and involvement in tissue calcification we conducted a comparative analysis of the ABCC6 gene and the related gene ABCC1 from invertebrates to vertebrates where a bony endoskeleton first evolved. Taking into consideration the role of ABCC6 in ectopic calcification of human skin we analysed the involvement of both genes in the regeneration of scales, mineralized structures that develop in fish skin. The ABCC6 gene was only found in bony vertebrate genomes and was absent from Elasmobranchs, Agnatha and from invertebrates. In teleost fish the abcc6 gene duplicated but the two genes persisted only in some teleost genomes. Six disease causing amino acid mutations in human MRP6 are a normal feature of abcc6 in fish, suggesting they do not have a deleterious effect on the protein. After scale removal the abcc6 (5 and 10 days) and abcc1 (10 days) gene expression was up-regulated relative to the intact control skin and this coincided with a time of intense scale mineralization.
- Betalains in some species of the amaranthaceae family: A reviewPublication . Miguel, MariaNatural pigments are largely distributed in the plant kingdom. They belong to diverse groups, with distinct biochemical pathways. Betalains with colours that range from yellow to red-violet can de divided into two main subgroups: betaxanthins and betacyanins. These types of pigments are confined into 13 families of the order Caryophyllales and in some genera of higher fungi (Amanita muscaria, Hygrocybe and Hygrophorus). The Amaranthaceae family includes diverse genera in which betalains are present: Alternanthera, Amaranthus, Beta, Chenopodium, Celosia and Gomphrena. The biosynthesis of betalains and their general biological properties were reviwed in the present work. In addition, the types of betalains present in some species of the aforementioned genera, their stability and production, as well as biological attributes, were reviewed.
- Collective electrical oscillations of a diatom population induced by dark stressPublication . Rocha, Paulo R. F.; Silva, Alexandra D.; Godinho, Lia; Dane, Willem; Estrela, Pedro; Vandamme, Lode K. J.; Pereira-Leal, Jose B.; de Leeuw, Dago M.; Leite, RicardoDiatoms are photosynthetic microalgae, a group with a major environmental role on the planet due to the biogeochemical cycling of silica and global fixation of carbon. However, they can evolve into harmful blooms through a resourceful communication mechanism, not yet fully understood. Here, we demonstrate that a population of diatoms under darkness show quasi-periodic electrical oscillations, or intercellular waves. The origin is paracrine signaling, which is a feedback, or survival, mechanism that counteracts changes in the physicochemical environment. The intracellular messenger is related to Ca2+ ions since spatiotemporal changes in their concentration match the characteristics of the intercellular waves. Our conclusion is supported by using a Ca2+ channel inhibitor. The transport of Ca2+ ions through the membrane to the extracellular medium is blocked and the intercellular waves disappear. The translation of microalgae cooperative signaling paves the way for early detection and prevention of harmful blooms and an extensive range of stress-induced alterations in the aquatic ecosystem.
- Organizational culture, internal marketing, and perceived organizational support in portuguese higher education institutionsPublication . Santos, Joana; Gonçalves, Gabriela Maria RamosChanges imposed on public higher education institutions try to adopt some management practices in public organizations. In this study, we intend to understand how organizational culture (support, innovation, goals, rules) and internal marketing can contribute to the organizational support of employees of higher education institutions. The study was developed with a sample of 635 employees. The results show that organizational culture and internal marketing contribute to the explanation of perceived organizational support (POS). Then, through a structural equation model, it was possible to confirm the contribution of support culture and internal marketing to the explanation of POS. More studies are necessary taking students' point of view into account. These results reveal the importance of the fact that organizations need to implement a culture of support and appropriate internal communication networks that allow employees to perceive social support.
- Simulation of the transport of suspended particles and dissolved pollutants by runoff on impervious surfaces: a contribution to urban sanitationPublication . Felice, Jessica Giacchetto; Silveira, Alexandre; MGP Isidoro, Jorge; Gonçalves, Flávio Aparecido; Silva, António Marciano daOne of the impacts of urbanization on the environment is the changes in the rainfall-runoff process, causing changes in water resources quality. The objective of this project was to simulate the transport of suspended particles and pollutants dissolved on runoff, an impermeable surface at laboratory scale. The experimental model consisted on a simulator for the application of artificial rainfall on an impermeable surface with 8,40 m(2), in which sodium chloride and fine sand were distributed in four defined regions, simulating sources of diffuse pollution. The results showed differences between peak transport times of dissolved and suspended pollutants, depending on their position. The first-flush effect was observed for the dissolved pollutants independently of the source position, whereas for the pollutants transported in suspension the same effect was only found when the source was closer to the outlet of the impervious surface.
- «O que se ergue do fogo é um lugar-corpo». Leituras da poesia de Adília CésarPublication . Nogueira, AdrianaUma possível leitura de dois livros de Adília César (Lagos, 1959): "O que se ergue do fogo", de 2016, e "Lugar-corpo", de 2017, enquadrando as questões por eles levantadas nas definições de Vergílio Ferreira («a interrogação está do lado do insondável. A pergunta desenvolve-se na clara horizontalidade; a interrogação, na obscura verticalidade», em "Invocação do meu corpo", p.20), considerando que estes poemas não têm referentes diretos num mundo prático da horizontalidade, mas que há um movimento interior que não se expande, não se expõe. Antecipado pelo primeiro livro, no segundo, esta nova poesia de Adília César acentua a verticalidade das suas interrogações.
- Implementação de um processo integrado de recrutamento, seleção e acolhimento na HubelPublication . Gonçalves, Cidália Baptista Rodrigues; Monteiro, Ileana Pardal; Correia, MarisolEste relatório de projeto discorre sobre a importância de avaliar os métodos de recrutamento e seleção, incluindo a análise de funções e de perfis, a fim de traçar linhas de orientação para a implementação de um projeto que visa facilitar e otimizar o recrutamento e a seleção, bem como a integração e a socialização de pessoas na organização, com particular foco na aplicabilidade das redes sociais online e do E-recrutamento numa empresa do setor privado. Por outro lado, pretende-se demonstrar a importância destes meios digitais na captação de candidatos com os perfis ideais para as funções propostas e como fatores facilitadores da integração e socialização de novos colaboradores. A primeira parte do trabalho incide sobre a descrição de conceitos de recrutamento e seleção, redes sociais online, E-recrutamento e o processo de integração, que foram o objeto do estudo. De seguida é apresentado um projeto empresarial, segundo uma abordagem técnico-científica, baseado na análise de funções e na definição de perfis, cujas informações são obtidas através de entrevistas semiestruturadas a especialistas da área dos recursos humanos e a responsáveis pelo recrutamento e seleção, bem como através de entrevistas a trabalhadores recém contratados na empresa, através das quais se pretende demonstrar a eficácia destes meios na ótica dos candidatos à procura de emprego. Concomitantemente é realizado um estudo de projeto para a implementação de novas ferramentas digitais na empresa. Este trabalho permite concluir que as descrições de funções e a definição de perfis são bases essenciais para os processos de recrutamento e seleção e para a integração de pessoas nas organizações. Por outro lado, o desenvolvimento de um novo Website articulado com Redes Sociais Online, para as quais foram criadas páginas empresariais, e o recurso aos portais de E-recrutamento, são uma mais-valia real para a organização, pois facilitam e aumentam a performance do processo de recrutamento e seleção, no que respeita à divulgação de ofertas de emprego e ao mesmo tempo promovem a imagem da empresa. A implementação destas ferramentas é fundamental para agilização do processo de recrutamento.