269 research outputs found

    Do Littoral Macrophytes Influence Crustacean Zooplankton Distribution?

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    In a meso-eutrophic reservoir, cladoceran and copepod assemblages were characterised in two sampling sites: One located in the pelagic zone (site 1) and the other in the shallow littoral zone (site 2), the latter colonised by emergent macrophytes. Samples were collected biweekly from June to July 2001 and from May to July 2002 at the two sites. At site 1, crustacean zooplankton samples were obtained by vertical hauls using a Wisconsin type net of 64 mm mesh size. At site 2 several random samples were obtained using a van Dorn bottle. Those samples were pooled together and the total sample was sieved through a 64 mm mesh size. Macrophyte relative abundance for each species was visually estimated. Macrophyte community was composed of Glyceria declinata, Eleocharis palustris and Carex sp. A Mann-Whitney U-test was carried out to test for statistically significant differences between sites, for environmental parameters and crustacean zooplankton species densities. Alona rectangula, Alona costata, Alona quadrangularis and Chydorus sphaericus were only found in littoral samples. Daphnia longispina, Daphnia pulex, Ceriodaphnia pulchella, Bosmina longirostris, Diaphanosoma brachyurum, Copidodiaptomus numidicus, and Acanthocyclops robustus were found at both sites. However, Daphnia and Bosmina densities did not differ significantly between the pelagic and littoral sites. Ceriodaphnia, Diaphanosoma, and C. numidicus densities were significantly higher in the pelagic site, whereas A. robustus densities showed the opposite pattern.En un embalse meso-eutrofico las comunidades de cladóceros y copépodos fueron caracterizadas en dos estaciones de muestreo. Una localizada en la zona pelágica (estación 1) y la otra en la zona litoral (estación 2). Esta última está colonizada por macrofitos emergidos. Los muestreos fueron efectuados quincenalmente de Junio a Julio de 2001 y de Mayo a Julio de 2002 en las dos estaciones. En la estación 1 los muestreos de crustáceos del zooplancton se obtuvieron mediante arrastre vertical utilizando una red tipo Wisconsin de 64 mm de poro. En la estación 2 se realizaron varias muestras aleatorias con una botella tipo van Dorn. Las muestras obtenidas en la estación 2 se juntaron y la muestra total resultante fue filtrada por una red de 64 mm de poro. La abundancia relativa de cada una de las especies de macrófitos fue estimada visualmente. La comunidad de macrófitos está constituida por Glyceria declinata, Eleocharis palustris y Carex sp. Fue realizado el test de U de Mann-Whitney para detectar las diferencias estadísticamente significativas entre las dos estaciones, para los parámetros ambientales y para las densidades de los crustáceos del zooplancton. Alona rectangula, Alona costata, Alona quadrangularis y Chydorus sphaericus se han observado únicamente en los muestreos obtenidos en el litoral. Daphnia longispina, Daphnia pulex, Ceriodaphnia pulchella, Bosmina longirostris, Diaphanosoma brachyurum, Copidodiaptomus numidicus y Acanthocyclops robustus se han encontrado en ambas estaciones, no obstante las densidades de Daphnia y Bosmina no presentan diferencias estadísticamente significativas entre la zona pelágica y la litoral. Las densidades de Ceriodaphnia, Diaphanosoma y C. numidicus fueran significativamente más elevadas en la zona pelágica, mientras que la densidad de A. robustus presentó un patrón opuesto

    Guest editorial

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    http://www.sciencedirect.com/science/article/B6TYP-46RDF5H-2/1/4d892d8249d5d0271e6b0a8dc9bd23a

    Research information management at ISCTE-IUL: the library’s role

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    ISCTE-IUL is a Portuguese public university with approximately 9000 students enrolled in undergraduate (46%) and postgraduate (54%) programs. The Repository of ISCTE-IUL is running since 2007 sustained by an Open Access Policy approved in the same year. In 2013, the current research information system – Ciência-IUL – became interoperable with the Repository bringing new challenges to SID, and allowing work collaboratively with other services to collect information, improve processes, and reduce duplication of efforts. SID seeks to support researchers throughout the research life cycle aiming to raise awareness of the academic community for Open Science best practices.info:eu-repo/semantics/publishedVersio

    Planar projection of mobile laser scanning data in tunnels

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    Laser scanning is now a common technology in the surveying and monitoring of large engineering infrastructures, such as tunnels, both in motorways and railways. Extended possibilities exist now with the mobile terrestrial laser scanning systems, which produce very large data sets that need efficient processing techniques in order to facilitate their exploitation and usability. This paper deals with the implementation of a methodology for processing and presenting 3D point clouds acquired by laser scanning in tunnels, making use of the approximately cylindrical shape of tunnels. There is a need for a 2D presentation of the 3D point clouds, in order to facilitate the inspection of important features as well as to easily obtain their spatial location. An algorithm was developed to treat automatically point clouds obtained in tunnels in order to produce rectified images that can be analysed. Tests were carried with data acquired with static and mobile Riegl laser scanning systems, by Artescan company, in highway tunnels in Portugal and Spain, with very satisfactory results. The final planar image is an alternative way of data presentation where image analysis tools can be used to analyze the laser intensity in order to detect problems in the tunnel structure

    Whole Genome Analysis of Gene Expression Reveals Coordinated Activation of Signaling and Metabolic Pathways during Pollen-Pistil Interactions in Arabidopsis

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    Plant reproduction depends on the concerted activation of many genes to ensure correct communication between pollen and pistil. Here, we queried the whole transcriptome of Arabidopsis (Arabidopsis thaliana) in order to identify genes with specific reproductive functions. We used the Affymetrix ATH1 whole genome array to profile wild-type unpollinated pistils and unfertilized ovules. By comparing the expression profile of pistils at 0.5, 3.5, and 8.0 h after pollination and applying a number of statistical and bioinformatics criteria, we found 1,373 genes differentially regulated during pollen-pistil interactions. Robust clustering analysis grouped these genes in 16 time-course clusters representing distinct patterns of regulation. Coregulation within each cluster suggests the presence of distinct genetic pathways, which might be under the control of specific transcriptional regulators. A total of 78% of the regulated genes were expressed initially in unpollinated pistil and/or ovules, 15% were initially detected in the pollen data sets as enriched or preferentially expressed, and 7% were induced upon pollination. Among those, we found a particular enrichment for unknown transcripts predicted to encode secreted proteins or representing signaling and cell wall-related proteins, which may function by remodeling the extracellular matrix or as extracellular signaling molecules. A strict regulatory control in various metabolic pathways suggests that fine-tuning of the biochemical and physiological cellular environment is crucial for reproductive success. Our study provides a unique and detailed temporal and spatial gene expression profile of in vivo pollen-pistil interactions, providing a framework to better understand the basis of the molecular mechanisms operating during the reproductive process in higher plants.Fundação para a Ciência e a Tecnologia grants: (FCT–PTDC/QUI/64339/06, SFRH/BD/1128/2000)

    Maximizing Blad-containing oligomerfungicidal activity in sweet cultivars of Lupinus albus seeds

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    During seed germination and plantlet growth, an important aspect of Lupinus β-conglutin proteolysis is the accumulation of blad in the cotyledons. Blad, a 20.4 kDa, 173 residue polypeptide which inhibits fungal growth, is the main subunit of BCO (Blad-containing oligomer), a Lupinus bioactive polypeptide oligomer, which underwent a successful translational research during the last thirty years. The development of this recent broad-spectrum biological fungicide for plant disease control made evident the advantage of being non-toxic to the environment, plants, humans and other animals, an interesting characteristic given the increasing consumer’s concern about food safety. The industrial-scale production of the edible fungicide BCO for agricultural purposes involves germinating and growing for ca. 8 days massive amounts of Lupinus plantlets. Therefore, it becomes economically relevant to maximize/increment the amount of extractable BCO. Although BCO represents an alternative pathway for lupin production in Europe, there is no previous evidence on lupin cultivars concerning BCO activity or its cotyledonary concentration, and therefore on the most promising cultivars for BCO extraction 16 and fungicide production. In this work, the amount of BCO and its level of fungicide activity was evaluated in seven sweet cultivars of L. albus (cvs. Amiga, Energy, Estoril, Ludic, Misak, Multitalia and Rumbo), along 20 days after the onset of germination. In addition, four distinct lots of cv. Energy and six lots of cv Misak, with different harvest years (1997, 2010, 2013 and 2014) and/or different sites of production in Portugal (Alto Alentejo, Baixo Alentejo and Beira Litoral) were also analysed. Quantitative assays demonstrated maximal accumulation of BCO in the cotyledons of 4-days-old L. albus plantlets, apart from significant differences between seeds’ harvest year or production site. The assays also showed that cv. Energy had significant higher accumulation of BCO (31.67 μg mg-1 wet weight) than Rumbo (25.67 μg mg-1) and Misak (22.12 μg mg-1), respectively second and third cultivars with highest accumulation of the oligomer. Additionally, very significant differences were also observed among seeds’ harvest year or production site. These observations reduced dramatically the original purpose of this work on the study of BCO variations at the level of sweet L. albus cultivars, since the ‘noise’ detected in BCO levels caused by the year and location of their production was far greater than its variation among cultivars. The observation that storing for several years the seeds at -20ºC did not seem to decrease BCO activity and suggests that the variation in cotyledonary BCO accumulation is essentially controlled by the prevailing edaphoclimatic conditions during seed formation. Furthermore, the activity tests exhibited significant antifungal activity between 3 and 5 days-old plantlets, with absence of antifungal activity on 8 days-old plantlets or older. Overall this study is of considerable importance to maximize BCO extraction from the cotyledons of sweet L. albus cultivarsinfo:eu-repo/semantics/acceptedVersio

    Genetic diversity increases with depth in red gorgonian populations of the Mediterranean Sea and the Atlantic Ocean

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    In the ocean, the variability of environmental conditions found along depth gradients exposes populations to contrasting levels of perturbation, which can be reflected in the overall patterns of species genetic diversity. At shallow sites, resource availability may structure large, persistent and well-connected populations with higher levels of diversity. In contrast, the more extreme conditions, such as thermal stress during heat waves, can lead to population bottlenecks and genetic erosion, inverting the natural expectation. Here we examine how genetic diversity varies along depth for a long-lived, important ecosystem-structuring species, the red gorgonian, Paramuricea clavata.Agência financiadora CESAM UID/AMB/50017/2019 Portuguese Foundation for Science and Technology FEDER, within the PT2020 Partnership Agreement FEDER, within the Compete 2020 Pew Marine Fellowship (USA) National Geographic Channel through project Deep Reefs, a National Geographic/Waitt grant W153-11 InAqua Conservation Fund (Oceanario de Lisboa) European Regional Development Fund (COMPETE program) Portuguese Foundation for Science and Technology SFRH/BPD/111003/2015 CCMAR/Multi/04326/2013 UID/MAR/04292/2013 PTDC/BIA-BIC/114526/2009 MARES Grant Joint Doctorate programme under Erasmus Mundus by Ghent University FPA 2011-0016info:eu-repo/semantics/publishedVersio

    As Bibliotecas de Ensino Superior e a gestão de ciência

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    As Bibliotecas de Ensino Superior (BES) com sistemas CRIS e repositórios institucionais a seu cargo têm vindo a adaptar-se no sentido de responder às necessidades dos seus utilizadores. Passaram a incluir funções de gestão de ciência com benefícios para a comunidade científica e para a instituição. Com a proliferação de plataformas digitais dedicadas à disseminação e comunicação de ciência surgiu a necessidade de apoiar os docentes e investigadores na atualização da sua produção científica e proceder à validação de metadados, ajudando a manter a qualidade e veracidade da informação e contribuir para a simplificação e transparência dos processos de avaliação da instituição. Pretende-se, com este trabalho, descrever a atividade de uma Biblioteca de Ensino Superior com funções de gestão de ciência, enfatizando a interação CRIS-repositório institucional, o processo de validação de metadados e a atualização de perfil de investigador e respetivos currículos dos docentes e investigadores.info:eu-repo/semantics/publishedVersio

    FACS-based purification of Arabidopsis microspores, sperm cells and vegetative nuclei

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    ABSTRACT: BACKGROUND: The male germline in flowering plants differentiates by asymmetric division of haploid uninucleated microspores, giving rise to a vegetative cell enclosing a smaller generative cell, which eventually undergoes a second mitosis to originate two sperm cells. The vegetative cell and the sperm cells activate distinct genetic and epigenetic mechanisms to control pollen tube growth and germ cell specification, respectively. Therefore, a comprehensive characterization of these processes relies on efficient methods to isolate each of the different cell types throughout male gametogenesis. RESULTS: We developed stable transgenic Arabidopsis lines and reliable purification tools based on Fluorescence-Activated Cell Sorting (FACS) in order to isolate highly pure and viable fractions of each cell/nuclei type before and after pollen mitosis. In the case of mature pollen, this was accomplished by expressing GFP and RFP in the sperm and vegetative nuclei, respectively, resulting in 99% pure sorted populations. Microspores were also purified by FACS taking advantage of their characteristic small size and autofluorescent properties, and were confirmed to be 98% pure. CONCLUSIONS: We provide simple and efficient FACS-based purification protocols for Arabidopsis microspores, vegetative nuclei and sperm cells. This paves the way for subsequent molecular analysis such as transcriptomics, DNA methylation analysis and chromatin immunoprecipitation, in the developmental context of microgametogenesis in Arabidopsis
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