Engenharia biológica : uma ferramenta para a conservação

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.Com o aumento da concentração humana em zonas litorais, que se tem vindo a assistir no ultimo século, as comunidades biológicas costeiras ficaram expostas a uma elevada pressão. Assim, quer uma série de actividades económicas e recreativas, quer a urbanização crescente das zonas costeiras provocam a destruição de habitats. Partes significativas da orla costeira são progressivamente substituídas por estruturas artificiais (portos, marinas, pontões, molhes, etc.,), o que e considerado, pela comunidade cientifica, como uma das principais razoes para a degradação dos ecossistemas costeiros. […]. Conscientes desta realidade, a Universidade dos Açores, em colaboração com investigadores do Reino Unido, desenvolveu um estudo em que testou a seguinte hipótese: seria possível aumentar a abundância de espécies ecologicamente importantes e com elevado interesse económico, em estruturas artificiais, recorrendo a engenharia biológica? Ou seja, através da inclusão experimental de micro-habitat nas estruturas artificiais, potenciar a abundância das espécies alvo. […].info:eu-repo/semantics/publishedVersio

Detecção sorológica de riquétsias do grupo da febre maculosa e levantamento acarológico em equinos no Distrito Federal, Brasil

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Agronomia e Veterinária, 2014.A febre maculosa brasileira (FMB) é uma zoonose causada pela bactéria Rickettsia rickettsii e transmitida a humanos por carrapatos. Procurou-se detectar a presença do principal agente etiológico da FMB circulando em equinos apreendidos no Distrito Federal, Brasil. Durante um ano foram coletadas amostras de sangue e ectoparasitos de 122 equinos. Após teste por reação de imunofluorescência indireta (RIFI), para anticorpos IgG anti R. rickettsii 21 amostras foram positivas em titulações variáveis de 1:64 a 1:512. Dos 618 carrapatos coletados, 449 pertenciam ao gênero Anocentor, 113 ao Boophilus e 36 do gênero Amblyomma. Como conclusão foi possível identificar a circulação de Rickettsia em equinos no DF, Brasil. ______________________________________________________________________________________ ABSTRACTThe Brazilian spotted fever (BSF) is a zoonosis caused by the bacteria Rickettsia rickettsii and transmitted to humans by ticks. In this study we tried to detect the BSF ethiological agent in horses apprehended by animal control in Distrito Federal, Brazil. Over one year the blood and ectoparasites were sampled on 122 horses. The samples were tested by indirect imunnofluorescence antibody assay (IFA) for R. rickettsii anti-IgG antibody, 21 samples were positive for titer ranging from 1:64 to 1:512. Among the 618 ticks collected, 449 belonged to the Anocentor genus, 113 to Boophilus and 36 were Amblyomma. The bacteria were detected in horses in Distrito Federal

COMMUNITY STRUCTURE AND DYNAMICS OF THE AZOREAN ROCKY INTERTIDAL: EXPLOITATION OF KEYSTONE SPECIES

Experimental work has shown the importance of grazing by patellid limpets in structuring intertidal assemblages. Little is known, however, about the effects of a largescale and chronic removal of limpets. Here I investigate the ecology of Patella candei, a seldom-studied limpet endemic to Macaronesia, and how its long-term fishery impacts the Azorean rocky intertidal. The specific aims of this thesis are to: examine the processes that affect the distribution of limpets in the Azores at a range of spatial scales; investigate the role of grazing by P. candei in structuring the Azorean rocky intertidal and if its harvesting has impacted the dynamics and functioning of this ecosystem. The distribution of limpets was variable at a range of spatial scales. At the scale of islands, inter-island variation in harvesting intensity affected the abundance and size structure of populations of limpets as well as the balance between grazers, algae and barnacles. Stocks of limpets showed clear signs of exploitation and there was evidence that current legislation, including limpet protected zones, have been largely ineffective in protecting these populations. At smaller spatial scales, substratum micro-topography influenced the distribution and sui-vival of limpets. I also showed that the experimental provision of microhabitats could be used as a measure to mitigate the effects of coastal urbanisation, whilst promoting a local enhancement of the stocks of limpets. Overall my results provide evidence for the population and community level effects of limpet harvesting and show that limpet harvesting has a strong impact on the structure and fiinctioning of the Azorean rocky intertidal.University of the Azores. Marine Biological Association of the U

Subcellular localization and dynamics of transmembrane and membrane associated proteins in Corynebacterium glutamicum

The cytoplasmic membrane of Corynebacterium glutamicum comprises 660 predicted membrane integral proteins of various functional categories, including transport, signal transduction, protein translocation, proteolysis and energy metabolism. Being an important industrial producer of amino acids, studying the membrane proteome of this organism is relevant for a better understanding of its fundamental processes and possible targeted optimizations. Here, we analyzed the subcellular localization of different transmembrane and membrane-associated proteins of Corynebacterium glutamicum, including the fructose specific PtsF and the glucose specific PtsG transporters, the respiratory chain complex II component SdhA, the small-conductance mechanosensitive channel YggB, and the polar/septa scaffold DivIVA. Using widefield and single molecule localization microscopy, we discovered that PtsG and PtsF form membrane embedded clusters with no defined positions. A similar pattern was observed for SdhA, which curiously, seem to colocalize with PtsF in our widefield microscopy experiments. Size, number and fluorescence of the observed PTS clusters change upon presence or absence of the transported substrate. In presence of the transport substrate, clusters significantly increased in size. Photo-activated localization microscopy (PALM) data revealed that, in presence of different carbon sources, the number of EII proteins per cluster remains the same, however the density of these clusters reduces. Our work reveals a simple mechanism for efficient membrane occupancy regulation. Clusters of PTS EII transporters are densely packed in absence of a suitable substrate. In presence of a transported substrate, the EII proteins in individual clusters occupy larger membrane areas. This mechanism allows for efficient use of the limited membrane space under varying growth conditions without need of protein removal and re-synthesis. Clustering was also observed in YggB, that localized in a punctate pattern of different intensities at the membrane. By changing the NaCl concentration in medium, ranging from 0 mM to 170 mM, we could observe C. glutamicum cells under different degrees of osmotic stress, ranging from hypoosmotic to low hyperosmotic. The extreme studied treatments resulted in impaired growth, which suggests that the cells were indeed under constant osmotic stress. Under such conditions, no changes in YggB-mNeonGreen foci number or fluorescence were observed, hinting that yggB expression is constitutive and that prolonged exposure to osmotic stress does not result in the recruitment of more channels to the membrane. Finally, we studied the dynamics of DivIVA in cells of various shapes, including L-form cells with different morphologies by performing widefield microscopy and fluorescence recovery after photobleaching (FRAP) experiments with a strain expressing DivIVA-mCherry. DivIVA is a membrane-associated protein that serves as a scaffold for different proteins related to cell division and cell growth. Cell division in bacterial L-forms is unlike the coordinated and precise division observed in cell-walled bacteria. It takes place randomly, not necessarily linked to the divisome and is highly influenced by perturbations in the surrounding environment. Due to this, it is not uncommon to find L-form cells with multiple, parts of, or no chromosomes. Still, in these cells, DivIVA continues to localize in regions of negative curvatures, characterized as bumps in the cytoplasmic membrane. In completely spherical cells, with no regions of higher negative curvature, DivIVA localize as larger foci. Our FRAP results demonstrated that in regions of bumps, the diffusion rate of DivIVA-mCherry is similar to the one observed for poles of rod-shaped cells, but with a significant lower half-time recovery. Furthermore, the diffusion rate on smooth surfaces was more than double, and the half-time recovery less half as the one observed in bumps. This suggests that DivIVA is significantly more mobile in such regions. Moreover, using novel microscopy techniques, the work presented on this thesis shed a light on unexplored facets of membrane protein compartmentalization in Corynebacterium glutamicum.Die Zytoplasmamembran von Corynebacterium glutamicum beherbergt 660 annotierte Membranintegralproteine, die verschiedene Funktionen in Transport, Signaltransduktion, Proteintranslokation, Proteolyse und Energiestoffwechsel wahrnehmen. Da C. glutamicum eine wichtige Rolle in der industriellen Aminosäureproduktion spielt, ist die Untersuchung des Membran-Proteoms wichtig für ein besseres Verständnis grundlegender Prozesse und gezielter Optimierung der Produktionsprozesse. In dieser Arbeit wurde die subzelluläre Lokalisation verschiedener Transmembran- und membranassoziierter Proteine von C. glutamicum analysiert. Dazu gehörten der Fructose-spezifische PtsF- und der Glucose-spezifische PtsG-Transporter, die Komponente SdhA des Komplexes II der Atmungskette, der mechanosensitive Kanal YggB und das am Zellpol lokalisierte Gerüstprotein DivIVA. Unter Verwendung von Weitfeld- und Einzelmolekül-Lokalisationsmikroskopie konnte gezeigt werden, dass PtsG und PtsF in Membranen eingebettete Cluster ohne definierte Positionen bilden. Ein ähnliches Muster wurde für SdhA beobachtet, das in Weitfeldmikroskopie-Experimenten interessanterweise mit PtsF zu kolokalisieren scheint. Größe, Anzahl und Fluoreszenz der beobachteten PTS-Cluster änderten sich bei Anwesenheit oder Abwesenheit des transportierten Substrats. In Gegenwart des transportierten Substrats nahm die Größe der Cluster signifikant zu. Daten der photoaktivierbaren Lokalisationsmikroskopie (PALM) ergaben, dass in Gegenwart verschiedener Kohlenstoffquellen die Anzahl der EII-Proteine pro Cluster konstant bleibt, die Dichte dieser Cluster jedoch abnimmt. Diese Arbeit zeigt einen einfachen Mechanismus zur effizienten Regulierung der Membranbelegung. Cluster von PTS-EII-Transportern sind in Abwesenheit eines geeigneten Substrats dicht gepackt. In Gegenwart eines transportierten Substrats besetzen die EII-Proteine in einzelnen Clustern größere Membranflächen. Dieser Mechanismus ermöglicht die effiziente Nutzung des begrenzten Membranraums unter verschiedenen Wachstumsbedingungen, ohne dass Proteine entfernt und erneut synthetisiert werden müssen. Clusterbildung wurde auch bei YggB beobachtet, das in einem punktförmigen Muster unterschiedlicher Intensität an der Membran lokalisiert war. Durch Änderung der NaCl-Konzentration im Medium im Bereich von 0 mM bis 170 mM konnten wir C. glutamicum-Zellen unter osmotischem Stress beobachten, der von hypo- bis leicht hyperosmotisch reichte. Unter Extrembedingungen ließ sich ein negativer Effekt auf das Wachstum beobachten, was darauf hindeutet, dass die Zellen tatsächlich einem konstanten osmotischen Stress ausgesetzt waren. Auch unter solchen Bedingungen wurden keine Änderungen der Anzahl an YggB-mNeonGreen-Foci oder der Fluoreszenz beobachtet, was darauf hindeutet, dass die yggB-Expression konstitutiv ist und dass eine längere Exposition gegenüber osmotischem Stress nicht zur Rekrutierung weiterer YggB-Kanäle an die Membran führt. Schließlich wurde die Dynamik von DivIVA in Zellen verschiedener Formen, einschließlich L-Formen mit unterschiedlichen Morphologien, untersucht. Hierfür wurde ein DivIVA-mCherry-exprimierender Stamm sowohl mittels Weitfeldmikroskopie, als auch mittels Fluorescence Recovery After Photobleaching (FRAP) analysiert. DivIVA ist ein membranassoziiertes Protein, das als Gerüst für verschiedene Proteine dient, die mit der Zellteilung und dem Zellwachstum zusammenhängen. Die Zellteilung in bakteriellen L-Formen unterscheidet sich von der koordinierten und präzisen Teilung, die bei Bakterien mit Zellwänden beobachtet wird. Sie findet zufällig statt, ist nicht notwendigerweise mit dem Divisom verbunden und wird stark von Störungen in der Umgebung beeinflusst. Aus diesem Grund ist es nicht ungewöhnlich, L-förmige Zellen mit mehreren, oder auch ganz ohne Chromosomen zu finden. Dennoch lokalisiert DivIVA in diesen Zellen weiterhin in Regionen mit negativen Krümmungen, die als „Ausbuchtungen“ in der Zytoplasmamembran zu sehen sind. In vollständig kugelförmigen Zellen ohne Bereiche mit höherer negativer Krümmung lokalisiert DivIVA in größeren Foci. Unsere FRAP-Experimente zeigten, dass die Diffusionsrate von DivIVA-mCherry in Regionen mit hohes Membrankrümmung der von Polen stäbchenförmiger Bakterien ähnelt, jedoch mit signifikant geringerer Halbwertszeit in der Erholungsphase. Unsere Daten zeigen, dass die DivIVA Dynamik von der Zellgeometrie beeinflusst wird. Da DivIVA über die Rekrutierung des Zellwand-Synthese Apparates an der Ausbildung der Zellmorphologie beteiligt ist, stellt dieses System ein einfaches aber effektives Konzept der bakteriellen Selbstorganisation dar. Darüber hinaus war die Diffusionsrate auf wenig gekrümmten Oberflächen mehr als doppelt so hoch und die Halbwertszeit halb so hoch wie die Diffusionsrate in Regionen mit hohes Membrankrümmung. Dies deutet darauf hin, dass DivIVA in solchen Regionen wesentlich mobiler ist. zusammenfassend klären die in dieser Arbeit vorgestellten Daten mithilfe neuartiger Mikroskopietechniken noch nicht erforschte Facetten der Kompartimentierung von Membranproteinen in Corynebacterium glutamicum auf

Perfil Epidemiológico e clínico de pacientes com doença renal policística do adulto em hospitais de Florianópolis.

Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Clínica Médica

Speaker change detection using BIC: a comparison on two datasets

Abstract — This paper addresses the problem of unsupervised speaker change detection. We assume that there is no prior knowledge on the number of speakers or their identities. Two methods are tested. The first method uses the Bayesian Information Criterion (BIC), investigates the AudioSpectrumCentroid and AudioWaveformEnvelope features, and implements a dynamic thresholding followed by a fusion scheme. The second method is a real-time one that uses a metric-based approach employing line spectral pairs (LSP) and the BIC criterion to validate a potential change point. The experiments are carried out on two different datasets. The first set was created by concatenating speakers from the TIMIT database and is referred to as the TIMIT data set. The second set was created by using recordings from the MPEG-7 test set CD1 and broadcast news and is referred to as the INESC dataset. I

THE APPALACHIAN SYSTEM OF BASINS AND PLATFORMS AS A TECTONOSTRATIGRAPHIC ANALOGUE TO THE BARENTS SEA SHELF: WHERE ARCTIC MEETS THE APPALACHIANS

Divided between Norway and Russia, the Barents Sea shelf (BSS) is an ~1.4 million km2 Arctic province, containing significant hydrocarbon accumulations. However, much of the area is frontier, and geologic data are often restricted or unavailable. One strategy to mitigate lack of geologic data is the use of analogues from well-known, mature basins. Even though there have been attempts to use analogues to study the geology of the BSS, such use is limited. Moreover, no analogue, to my knowledge, has been capable of addressing the regional tectonostratigraphic development of the shelf as a whole. In this research, the Appalachian system of basins and platforms and its included flexural stratigraphic sequences are defined as a tectonostratigraphic analogue, aiding the interpretation of BSS tectonostratigraphic evolution. Although temporally and paleogeographically different, both the Appalachian and BSS areas reflect collisional regimes, characterized by early subduction-related orogenies that concluded with a final collisional event. In the Appalachian foreland basin and adjacent intracratonic areas, each orogeny was defined by one or more, unconformity-bound, flexural stratigraphic sequences, called “tectophase” sequences. The BSS tectonostratigraphic succession exhibits several unconformity-bound stratigraphic sequences that are comparable to tectophase sequences from the Appalachian area. These BSS sequences begin with black shales and end with molasse-like wedges of clastic sediments, which suggest flexural responses to orogeny. Much of this succession was deposited across structural elements that were likely reactivated by far-field responses to periods of Uralian–Pai–Khoi–Novaya Zemlya (Late Permian to Middle Jurassic) tectonism, involving the collision of Siberia-Kazakhstania with northern Baltican parts of Pangea. This widespread structural reactivation is discussed herein by applying the backstripping method for analysis of structural mechanisms, based on sediment thicknesses across various BSS structural elements. As in the Appalachian area, BSS structural reactivation occurred in various ways and times during ongoing Uralian–Pai–Khoi–Novaya Zemlya tectonism. In this context, the only part of the BSS collisional succession with sufficient lithologic data for regional studies is the Upper Triassic–Lower Jurassic (Carnian–Hettangian) stratigraphic succession. This succession includes erosional surfaces, as well as open-marine, marginal-marine and fluvio-deltaic deposits, and the varying nature and thicknesses of these sediments across the several BSS structural elements suggest far-field reactivation by the coeval Novaya Zemlya Orogeny. The Appalachian tectophase cycle is herein used to define pulses (tectophases) of deformational loading and possible sedimentary responses to foreland-basin and forebulge development. Although many BSS models suggest that tectonism in the area did not begin until the Late Triassic–Early Jurassic transition, sedimentary responses similar to those in the Appalachian tectophase model suggest that tectonism may have begun as early as Late Triassic (Norian) time. Even though many questions remain, the use of analogues external to the BSS, has not been a widespread practice. However, mature collisional settings like the Appalachian and BSS areas typically exhibit similar large-scale processes, meaning that analogues from one may provide new sources of information about the other

Impact of chromossomal structure on the evolution of Schizosaccharomyces pombe undergoing Mutation Accumulation

Large chromosomal rearrangements are common in natural populations and thought to be involved in speciation events. In this project, we used experimental evolution to determine how the speed of evolution and the type of accumulated mutations depend on the ancestral chromosomal structure and genotype. We utilized two Wild Type strains and a set of genetically engineered Schizosaccharomyces pombe strains, different solely in the presence of a certain type of chromosomal variant (inversions or translocations), along with respective controls. Previous research has shown that these chromosomal variants have different fitness levels in several environments, probably due to changes in the gene expression along the genome. These strains were propagated in the laboratory at very low population sizes, in which we expect natural selection to be less efficient at purging deleterious mutations. We then measured these strains’ changes in fitness throughout this accumulation of deleterious mutations, comparing the evolutionary trajectories in the different rearrangements to understand if the chromosomal structure affected the speed of evolution. We also tested these mutations for possible epistatic effects and estimated their parameters: the number of arising deleterious mutations per generation (Ud) and each one’s mean effect (sd)

Lapas : pequenas Ilhas de diversidade

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.[…]. Um estudo recente feito por investigadores do Centro de Investigação em Recursos Naturais da Universidade dos Açores examinou a diversidade de organismos que vivem sob as conchas da lapa Patella aspera. As lapas desempenham um papel importante nos ecossistemas uma vez que controlam a abundancia de algas prevenindo desta forma que estas monopolizem o espaço, permitindo assim a fixação de outro tipo de organismos como por exemplo a pequena craca Chthamalus stellatus. No entanto, o presente estudo mostrou que para alem do papel importante na ecologia das nossas costas, as lapas desempenham ainda um outro papel ao suportarem em si mesmas uma extraordinária diversidade. Foram observados um total de 707 conchas de lapa recolhidas em todas as ilhas do arquipélago nas quais se registaram uns surpreendentes 190 registos de espécies diferentes. […].info:eu-repo/semantics/publishedVersio

A urbanização nos ecossistemas costeiros : implicações para a biodiversidade

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.[…]. A urbanização dos habitats costeiros, incluindo a construção de estruturas de defesa costeiras, como paredões, quebra-mares ou espigões, tem vindo a aumentar como resposta às previsões para o aumento do nível do mar, maior ocorrência de tempestades e aumento do transporte marítimo. O efeito destes habitats artificiais numa variedade de organismos marinhos tem recebido pouca atenção, apesar de ser fundamental para estabelecer diretrizes para a correta gestão das áreas costeiras urbanizadas. Existe, por tanto, um claro interesse em compreender as consequências ambientais da urbanização, razão que esteve na base do desenvolvimento dum projeto de investigação levado a cabo pelo grupo de Investigação Aquática Macaronésia (IAM) entre os anos 2013 e 2015. O IAM, integrado no CIIMAR é composto por elementos do Departamento de Biologia da Universidade dos Açores, coordenou o projeto “Estruturas urbanas: um fator de mudança na biodiversidade dos ecossistemas costeiros”. O projeto foi financiado pela Fundação para a Ciência e a Tecnologia e contou com a Prof. Ana I. Neto como investigadora responsável e com a Faculty of Science and Environment da Universidade de Plymouth como entidade colaboradora externa. […].info:eu-repo/semantics/publishedVersio