544 research outputs found

    Minimalist Approach for the Design of Microstructured Optical Fiber Sensors

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    We report on recent investigations regarding ultra-simplified designs for microstructured optical fiber sensors. This minimalist approach relies on the utilization of capillary-like fibers—namely embedded-core fibers, surface-core fibers, and capillary fibers—as platforms for the realization of sensing measurements. In these fibers, guidance of light is accomplished in an embedded or surface germanium-doped core or in the hollow part of capillaries. External stimuli can alter fiber wall thickness and/or induce birefringence variations, allowing, for the embedded-core and capillary fibers, to operate as pressure or temperature sensors. For the surface-core fiber design, the interaction between the guided mode and external medium allows the realization of refractive index sensing either by using fiber Bragg gratings or surface plasmon resonance phenomenon. Also, we report the realization of directional curvature sensing with surface-core fibers making use of the off-center core position. The attained sensitivities are comparable to the ones obtained with much more sophisticated structures. The results demonstrate that these novel geometries enable a new route toward the simplification of optical fiber sensors

    Human case of West Nile neuroinvasive disease in Portugal, summer 2015

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    A case of West Nile virus (WNV) infection was reported in the Algarve region, Portugal, in the first week of September 2015. WNV is known to circulate in Portugal, with occasional reports in horses and birds (2004 to 2011) and very sporadically human cases (in 2004 and in 2010). Here we present the clinical and laboratory aspects related to the first human case of West Nile neuroinvasive disease reported in Portugal

    PIG-1 MELK-dependent phosphorylation of nonmuscle myosin II promotes apoptosis through CES-1 Snail partitioning

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    The mechanism(s) through which mammalian kinase MELK promotes tumorigenesis is not understood. We find that the C. elegans orthologue of MELK, PIG-1, promotes apoptosis by partitioning an anti-apoptotic factor. The C. elegans NSM neuroblast divides to produce a larger cell that differentiates into a neuron and a smaller cell that dies. We find that in this context, PIG-1 is required for partitioning of CES-1 Snail, a transcriptional repressor of the pro-apoptotic gene egl-1 BH3-only. pig-1 MELK is controlled by both a ces-1 Snail- and par-4 LKB1-dependent pathway, and may act through phosphorylation and cortical enrichment of nonmuscle myosin II prior to neuroblast division. We propose that pig-1 MELK-induced local contractility of the actomyosin network plays a conserved role in the acquisition of the apoptotic fate. Our work also uncovers an auto-regulatory loop through which ces-1 Snail controls its own activity through the formation of a gradient of CES-1 Snail protein

    West Nile virus [Flavivirus] infection in Portugal. Considerations about a clinical case with febrile syndrome and rash

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    O vírus West Nile [WN] é um flavivírus transmitido por mosquitos e agente etiológico de febre e de doença neuroinvasiva. O vírus WN mantém-se na natureza em ciclos enzoóticos que envolvem mosquitos ornitofílicos, como vectores primários, e algumas espécies de aves como reservatório primário. A sua presença em Portugal é conhecida, surgindo esporadicamente alguns casos de infecção em equinos e humanos. Em 2010 foi identificado um caso humano detectado em toda a época de actividade de mosquitos nesse ano. Neste caso a paciente apresentava quadro febril com hiperpirexia muito irregular, por vezes com calafrios e picos de febre superiores a 39ºC, cefaleias, mialgias, adinamia e astenia acentuada, adenomegalias volumosas e dolorosas na região cervical, assim como exantema eritematoso difuso com maior expressão no tronco. Os exames laboratoriais identificaram seroconversão de anticorpos IgM contra o vírus West Nile

    Different isolation approaches lead to diverse glycosylated extracellular vesicle populations

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    Extracellular vesicles (EVs) are a heterogeneous group of small secreted particles involved in inter-cellular communication and mediating a broad spectrum of biological functions. EVs cargo iscomposed of a large repertoire of molecules, including glycoconjugates. Herein, we report the firststudy on the impact of the isolation strategy on the EV populations’glycosylation profile. The use ofdifferent state-of-the-art protocols, namely differential ultracentrifugation (UC), total exosome isola-tion (TEI), OptiPrepTMdensity gradient (ODG) and size exclusion chromatography (SEC) resulted in EVpopulations displaying different sets of glycoconjugates. The EV populations obtained by UC, ODGand SEC methods displayed similar protein and glycan profiles, whereas TEI methodology isolated themost distinct EV population. In addition, ODG and SEC isolation protocols provided an enhanced EVglycoproteins detection. Remarkably, proteins displaying the tumour-associated glycan sialyl-Tn(STn) were identified as packaged cargo into EVs independently of the isolation methodology. STncarrying EV samples isolated by UC, ODG and SEC presented a considerable set of cancer-relatedproteins that were not detected in EVs isolated by TEI. Our work demonstrates the impact of usingdifferent isolation methodologies in the populations of EVs that are obtained, with consequences inthe glycosylation profile of the isolated population. Furthermore, our results highlight the importanceof selecting adequate EV isolation protocols and cell culture conditions to determine the structuraland functional complexity of the EV glycoconjugates.This work was funded by FEDER funds through theOperational Programme for Competitiveness Factors-COMPETE (POCI-01-0145-FEDER-016585; POCI-01-0145-FEDER-007274; POCI-01-0145-FEDER-028489) and NationalFunds through the Foundation for Science and Technology(FCT), under the projects: PTDC/BBB-EBI/0567/2014 (toCAR), PTDC/MED-ONC/28489/2017 (to AM) and UID/BIM/04293/2013; and the project NORTE-01-0145-FEDER-000029, supported by Norte Portugal Regional Programme(NORTE 2020), under the PORTUGAL 2020 PartnershipAgreement, through the European Regional DevelopmentFund (ERDF). DF acknowledges the FCT PhD Programmesand Programa Operacional Potencial Humano (POPH), speci-fically the Biotech Health Programme (Doctoral Programme onCellular and Molecular Biotechnology Applied to HealthSciences), with the reference PD/0016/2012 funded by FCTand the grant SFRH/BD/110636/2015 from FCT, POPH andFSE (Fundo Social Europeu); MB acknowledges the EuropeanUnion’s Horizon 2020 research and innovation programmeunder the Marie Sklodowska-Curie grant agreement No.748880; and JP acknowledges FCT (SFRH/BD/137319/2018).The authors acknowledge Rede Nacional de Espectrometria deMassa, ROTEIRO/0028/2013, ref. LISBOA-01-0145-FEDER-022125, supported by COMPETE and North PortugalRegional Operational Programme (Norte2020), under thePORTUGAL 2020 Partnership Agreement, through theEuropean Regional Development Fund (ERDF). SV acknowl-edges the Danish National Research Foundation (DNRF107)

    Robust gap repair in the contractile ring ensures timely completion of cytokinesis.

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    Cytokinesis in animal cells requires the constriction of an actomyosin contractile ring, whose architecture and mechanism remain poorly understood. We use laser microsurgery to explore the biophysical properties of constricting rings in Caenorhabditis elegans embryos. Laser cutting causes rings to snap open. However, instead of disintegrating, ring topology recovers and constriction proceeds. In response to severing, a finite gap forms and is repaired by recruitment of new material in an actin polymerization-dependent manner. An open ring is able to constrict, and rings repair from successive cuts. After gap repair, an increase in constriction velocity allows cytokinesis to complete at the same time as controls. Our analysis demonstrates that tension in the ring increases while net cortical tension at the site of ingression decreases throughout constriction and suggests that cytokinesis is accomplished by contractile modules that assemble and contract autonomously, enabling local repair of the actomyosin network. Consequently, cytokinesis is a highly robust process impervious to discontinuities in contractile ring structure.This project has received funding from the European Research Council (grants 640553, 260892, and 338410), Fundo Europeu de Desenvolvimento Regional (FED ER) funds through the Operational Competitiveness Program (COM PETE), national funds through Fundação para a Ciência e a Tecnologia (FCT) under the project FCO MP-01-0124-FED ER-028255 (PTDC/BEX-BCM/0654/2012), Fundação Luso-Americana para o Desenvolvimento Life Science 2020, and the Louis-Jeantet Young Investigator Award to H. Maiato. A.X. Carvalho, R. Gassmann, and I.A. Telley have FCT Investigator positions funded by FCT and cofunded by the European Social Fund through Programa Operacional Temático Potencial Type 4.2 promotion of scientific employment. A.M. Silva holds an FCT fellowship (SFRH/BPD/95707/2013). D.S. Osório was cofunded by the Programa Operacional Regional do Norte under the Quadro de Downloaded from jcb.rupress.org on February 27, 2018 Laser microsurgery in the contractile ring • Silva et al. 799 Referência Estratégico Nacional through FED ER and by FCT grant NOR TE-07-0124-FED ER-000003 (Cell Homeostasis Tissue Organization and Organism Biology)
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