574 research outputs found

    Aurora A triggers Lgl cortical release during symmetric division to control planar spindle orientation

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    Mitotic spindle orientation is essential to control cell-fate specification and epithelial architecture. The tumor suppressor Lgl localizes to the basolateral cortex of epithelial cells, where it acts together with Dlg and Scrib to organize apicobasal polarity. Dlg and Scrib also control planar spindle orientation, but how the organization of polarity complexes is adjusted to control symmetric division is largely unknown. Here, we show that the Dlg complex is remodeled during Drosophila follicular epithelium cell division, when Lgl is released to the cytoplasm. Lgl redistribution during epithelial mitosis is reminiscent of asymmetric cell division, where it is proposed that Aurora A promotes aPKC activation to control the localization of Lgl and cell-fate determinants. We show that Aurora A controls Lgl localization directly, triggering its cortical release at early prophase in both epithelial and S2 cells. This relies on double phosphorylation within the putative aPKC phosphorylation site, which is required and sufficient for Lgl cortical release during mitosis and can be achieved by a combination of aPKC and Aurora A activities. Cortical retention of Lgl disrupts planar spindle orientation, but only when Lgl mutants that can bind Dlg are expressed. Hence, our work reveals that Lgl mitotic cortical release is not specifically linked to the asymmetric segregation of fate determinants, and we propose that Aurora A activation breaks the Dlg/Lgl interaction to allow planar spindle orientation during symmetric division via the Pins (LGN)/Dlg pathway.We thank J. Knoblich, D. St Johnston, D. Bilder, D. Glover, S. Brogna, R. Martinho, H. Maiato, D. Bergstralh, and the Bloomington Stock Center for fly stocks and reagents. This work was funded by FEDER funds through the Operational Competitiveness Programme COMPETE and by National Funds through FCT (Fundação para a Ciência e a Tecnologia) under the project FCOMP-01-0124-FEDER-019738 (PTDC/BIA-BCM/120132/2010), which also supported fellowships to C.C. and S.M. E.M. was funded by a Marie Curie-IEF and currently holds a FCT Investigator position

    Fluorometric Liposome Screen for Inhibitors of a Physiologically Important Bacterial Ion Channel

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    The bacterial K+ homeostasis machinery is widely conserved across bacterial species, and different from that in animals. Dysfunction in components of the machinery has an impact on intracellular turgor, membrane potential, adaptation to changes in both extracellular pH and osmolarity, and in virulence. Using a fluorescence-based liposome flux assay, we have performed a high-throughput screen to identify novel inhibitors of the KtrAB ion channel complex from Bacillus subtilis, a component of the K+ homeostasis machinery that is also present in many bacterial pathogens. The screen identified 41 compounds that inhibited K+ flux and that clustered into eight chemical groups. Many of the identified inhibitors were found to target KtrAB with an in vitro potency in the low µM range. We investigated the mechanisms of inhibition and found that most molecules affected either the membrane component of the channel, KtrB alone or the full KtrAB complex without a preference for the functional conformation of the channel, thus broadening their inhibitory action. A urea derivative molecule that inhibited the membrane component of KtrAB affected cell viability in conditions in which KtrAB activity is essential. With this proof-of-concept study, we demonstrate that targeting components of the K+ homeostasis machinery has the potential as a new antibacterial strategy and that the fluorescence-based flux assay is a robust tool for screening chemical libraries.This work was supported by FEDER funds through COMPETE 2020-POCI, Portugal 2020, and FCT – Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior: POCI-01-0145-FEDER-029863 (PTDC/BIA-BQM/29863/2017), and by “Fundação Luso-Americana para o Desenvolvimento” FLAD Life Science 2020 awarded to JM-C. We acknowledge FCT fellowship SFRH/BPD/105672/2015 and contract DL 57/2016/CP1355/CT0026 awarded to AF, fellowship SFRH/BPD/107785/2015 to AP, and fellowship SFRH/BD/123761/2016 to CT-D

    PSK4 COST-EFFECTIVENESS OF TOPICAL CALCIPOTRIOL/BETAMETHASONE DIPROPIONATE TWOCOMPOUND PRODUCT IN A SCOTTISH CARE MODEL

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    PSK4 COST-EFFECTIVENESS OF TOPICAL CALCIPOTRIOL/BETAMETHASONE DIPROPIONATE TWOCOMPOUND PRODUCT IN A SCOTTISH CARE MODEL

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    Aprovada pel gerent de l'Institut Municipal d'Hisenda el 01-07-200

    In vitro and in vivo performance of methacrylated gellan gum hydrogel formulations for cartilage repair

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    Methacrylated gellan gum (GGMA) formulation is proposed as a second‐generation hydrogel for controlled delivery of cartilage‐forming cells into focal chondral lesions, allowing immediate in situ retention of cells and 3D filling of lesion volume, such approach deemed compatible with an arthroscopic procedure. Formulation optimization was carried out in vitro using chondrocytes and adipose mesenchymal stromal/stem cells (ASCs). A proof‐of‐concept in vivo study was conducted using a rabbit model with induced chondral lesions. Outcomes were compared with microfracture or non‐treated control. Three grading scores were used to evaluate tissue repair after 8 weeks by macroscopic, histological and immunohistochemical analysis. Intense collagen type II and low collagen type I gene and protein expression were achieved in vitro by the ASC + GGMA formulation, in light with development of healthy chondral tissue. In vivo, this formulation promoted significantly superior de novo cartilage formation compared with the non‐treated group. Maintenance of chondral height and integration with native tissue was further accomplished. The physicochemical properties of the proposed GGMA hydrogel exhibited highly favorable characteristics and biological performance both in vitro and in vivo, positioning itself as an attractive xeno‐free biomaterial to be used with chondrogenic cells for a cost‐effective treatment of focal chondral lesions

    Life cycle assessment of Polychlorinated Biphenyl contaminated soil remediation processes

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    Goal and scope. A life-cycle assessment (LCA) was performed to evaluate the environmental impacts of the remediation of industrial soils contaminated by polychlorobiphenyl (PCB). Two new bioremediation treatment options were compared with the usual incineration process. In this attributional LCA, only secondary impacts were considered. The contaminated soil used for the experiments contained 200 mg of PCB per kg. Methods. Three off-site treatments scenarios were studied: 1) bioremediation with mechanical aeration, 2) bioremediation with electric aeration and 3) incineration with natural gas. Bioremediation processes were designed from lab-scale, scale-up and pilot experiments. The incineration technique was inspired by a French plant. A semi-quantitative uncertainty analysis was performed on the data. Environmental impacts were evaluated with the CML 2001 method using the Simapro software program. Results and discussion. In most compared categories, the bioremediation processes are favorable. Of the bioremediation options, the lowest environmental footprint was observed for electric aeration. The uncertainty analysis supported the results that compared incineration and bioremediation but decreased the difference between the options of aeration. The distance of transportation was one of the most sensitive parameters, especially for bioremediation. At equal distances between the polluted sites and the treatment plant, bioremediation had fewer impacts than incineration in eight out of thirteen categories. Conclusions. The use of natural gas for the incineration process generated the most impacts. Irrespective of the aeration option, bioremediation was better than incineration. Recommendations. The time of treatment should be taken into account. More precise and detailed data are required for the incineration scenario. More parameters of biological treatments should be measured. LCA results should be completed using ecological and health risk assessment and an acceptability evaluation

    Serologically defined variations in malaria endemicity in Pará state, Brazil

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    BACKGROUND: Measurement of malaria endemicity is typically based on vector or parasite measures. A complementary approach is the detection of parasite specific IgG antibodies. We determined the antibody levels and seroconversion rates to both P. vivax and P. falciparum merozoite antigens in individuals living in areas of varying P. vivax endemicity in Pará state, Brazilian Amazon region. METHODOLOGY/PRINCIPAL FINDINGS: The prevalence of antibodies to recombinant antigens from P. vivax and P. falciparum was determined in 1,330 individuals. Cross sectional surveys were conducted in the north of Brazil in Anajás, Belém, Goianésia do Pará, Jacareacanga, Itaituba, Trairão, all in the Pará state, and Sucuriju, a free-malaria site in the neighboring state Amapá. Seroprevalence to any P. vivax antigens (MSP1 or AMA-1) was 52.5%, whereas 24.7% of the individuals were seropositive to any P. falciparum antigens (MSP1 or AMA-1). For P. vivax antigens, the seroconversion rates (SCR) ranged from 0.005 (Sucuriju) to 0.201 (Goianésia do Pará), and are strongly correlated to the corresponding Annual Parasite Index (API). We detected two sites with distinct characteristics: Goianésia do Pará where seroprevalence curve does not change with age, and Sucuriju where seroprevalence curve is better described by a model with two SCRs compatible with a decrease in force of infection occurred 14 years ago (from 0.069 to 0.005). For P. falciparum antigens, current SCR estimates varied from 0.002 (Belém) to 0.018 (Goianésia do Pará). We also detected a putative decrease in disease transmission occurred ∼29 years ago in Anajás, Goianésia do Pará, Itaituba, Jacareacanga, and Trairão. CONCLUSIONS: We observed heterogeneity of serological indices across study sites with different endemicity levels and temporal changes in the force of infection in some of the sites. Our study provides further evidence that serology can be used to measure and monitor transmission of both major species of malaria parasite
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