188 research outputs found

    In-depth proteomics identifies a role for autophagy in controlling reactive oxygen species mediated endothelial permeability

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    Endothelial cells (ECs) form the inner layer of blood vessels and physically separate the blood from the surrounding tissue. To support tissues with nutrients and oxygen, the endothelial monolayer is semipermeable. When EC permeability is altered, blood vessels are not functional, and this is associated with disease. A comprehensive knowledge of the mechanisms regulating EC permeability is key in developing strategies to target this mechanism in pathologies. Here we have used an in vitro model of human umbilical vein endothelial cells mimicking the formation of a physiologically permeable vessel and performed time-resolved in-depth molecular profiling using stable isotope labeling by amino acids in cell culture mass spectrometry (MS)-proteomics. Autophagy is induced when ECs are assembled into a physiologically permeable monolayer. By using siRNA and drug treatment to block autophagy in combination with functional assays and MS proteomics, we show that ECs require autophagy flux to maintain intracellular reactive oxygen species levels, and this is required to maintain the physiological permeability of the cells

    Investigation of E-cadherin dynamics in cancer cell adhesion and metastasis

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    E-cadherin is a cell adhesion protein required for epithelial tissue integrity. In many cancer cells mis-regulation of E-cadherin adhesions causes increased progression and invasion of cancer. Alteration in E-cadherin dynamics could therefore serve as an early molecular biomarker of metastasis. In this project, I used E-cadherin FRAP to asses real time dynamics of cadherin junctions in a pancreatic cancer mice model of in a variety of micro-environments. My data showed that p53 mutation drives metastasis through mobilizing E-cadherin in junctions. Also, I used FRAP as a pharmaco-dynamic marker to assess the effect of an anti-invasive drug (dasatinib) in pancreatic tumours in vivo. Moreover, my E-cadherin FRAP data along with cross-linking experiments and disruption of E-cadherin interactions by mutation provided a comprehensive framework for understanding E-cadherin dynamics at cell-cell. Here, I have identified four distinct populations of E-cadherin within regions of cell-cell contact and characterized the interactions governing their mobility using FRAP. These pancreatic cancer cells had the immobile fraction (Fi) of E-cadherin-GFP comprised adhesive and non-adhesive populations. The remaining mobile fraction (Fm) also comprised of non-adhesive and adhesive populations, one population moves at the rate of pure diffusion, and therefore represents free E-cadherin monomers. The other population moves more slowly, and represents E-cadherin monomers turning over within immobile complexes. Inclusion of E-cadherin into either adhesive population requires cis-, trans-, and actin interactions. The signaling pathways in cells dramatically affect the fractions of these cadherin components. I showed that understanding the dynamics of these four populations of E-cadherins could be used to design or interpretation of future pharmacological and genetic experiments to probe the function of E-cadherin in development, disease progression, and response to therapy

    Suzuki-Miyaura C-C Coupling Reactions Catalyzed by Supported Pd Nanoparticles for the Preparation of Fluorinated Biphenyl Derivatives

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    Heterogeneous recyclable catalysts in Suzuki-Miyaura C-C coupling reactions are of great interest in green chemistry as reusable alternatives to homogeneous Pd complexes. Considering the interesting properties of fluorinated compounds for the pharmaceutical industry, as precursors of novel materials, and also as components of liquid crystalline media, this present study describes the preparation of different fluorinated biphenyl derivatives by Suzuki-Miyaura coupling reactions catalyzed by a heterogeneous system (G-COOH-Pd-10) based on Pd nanoparticles supported onto COOH-modified graphene. The catalytic activity of the hybrid material G-COOH-Pd-10 has been tested in Suzuki-Miyaura C–C coupling reactions observing excellent versatility and good conversion rates in the reactions of phenylboronic acid, 4-vinylphenylboronic acid, 4-carboxyphenylboronic acid, and 4-fluorophenylboronic acid with 1-bromo-4-fluorobenzene. In addition, the influence of the arylbromide has been studied by carrying out reactions of 4-fluorophenylboronic acid with 1-bromo-2-fluorobenzene, 1-bromo-3-fluorobenzene, 1-bromo-4-fluorobenzene, 2-bromo-5-fluorotoluene, and 2-bromo-4-fluorotoluene. Finally, catalyst recyclability tests show a good degree of reusability of the system based on G-COOH-Pd-10 as the decrease in catalytic activity after five consecutive catalytic cycles in the reaction of 1-bromo-4-fluorobenzene with 4-florophenylboronic acid at 48 hours of reaction is lower than 8% while in the case of reactions at three hours the recyclability of the systems is much lower.We gratefully acknowledge financial support from the Ministerio de Economía y Competitividad, Spain (Grant no. CTQ2015-66164-R). We would also like to thank Universidad Rey Juan Carlos and Banco de Santander for supporting our Research Group of Excellence QUINANOAP. We would also like to thank Isfahan University of Technology for the partial financial support of the research stay of R.S.E

    Applications of Nanomaterials Based on Magnetite and Mesoporous Silica on the Selective Detection of Zinc Ion in Live Cell Imaging

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    Functionalized magnetite nanoparticles (FMNPs) and functionalized mesoporous silica nanoparticles (FMSNs) were synthesized by the conjugation of magnetite and mesoporous silica with the small and fluorogenic benzothiazole ligand, that is, 2(2-hydroxyphenyl)benzothiazole (hpbtz). The synthesized fluorescent nanoparticles were characterized by FTIR, XRD, XRF, 13C CP MAS NMR, BET, and TEM. The photophysical behavior of FMNPs and FMSNs in ethanol was studied using fluorescence spectroscopy. The modification of magnetite and silica scaffolds with the highly fluorescent benzothiazole ligand enabled the nanoparticles to be used as selective and sensitive optical probes for zinc ion detection. Moreover, the presence of hpbtz in FMNPs and FMSNs induced efficient cell viability and zinc ion uptake, with desirable signaling in the normal human kidney epithelial (Hek293) cell line. The significant viability of FMNPs and FMSNs (80% and 92%, respectively) indicates a potential applicability of these nanoparticles as in vitro imaging agents. The calculated limit of detections (LODs) were found to be 2.53 X 10-6 and 2.55 X 10-6 M for Fe3O4-H@hpbtz and MSN-Et3N-IPTMS-hpbtz-f1, respectively. FMSNs showed more pronounced zinc signaling relative to FMNPs, as a result of the more efficient penetration into the cells.This research was funded by several sources. The URJC authors thank the financial support of theMinisterio de Economía y Competitividad and FEDER (Grants nos. CTQ2015-66164-R and CTQ2017-90802-REDT) and Universidad Rey Juan Carlos-Banco de Santander for supporting our excellence group QUINANOAP. The partial support of this work by the Isfahan University of Technology Research Council (grant number 500/95/24305 and the Iran National Science Foundation through INSF grant number 95828071 is also acknowledged. The CNIC is supported by the Spanish Ministerio de Ciencia, Innovación y Universidades and the Pro-CNIC Foundation and is a Severo Ochoa Center of Excellence (SEV-2015-0505). M.F. would like to thank MEyC for the research grant no. SAF2014-59118-JIN, co-funded by Fondo Europeo de Desarrollo Regional (FEDER) and COST Action CA1520: ‘European Network on NMR Relaxometry-EURELAX’. M.F. would also like to thank the Community of Madrid for research contract num. 2017-T1/BIO-4992 (‘Atraccion de Talento’ Action) cofunded by Universidad Complutense de Madrid

    The prevalence of staphylococcus aureus contamination in the ambulances and on-call emergency medical service personnel of kashan city in iran

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    Objective: Emergency medical services systems are at the first line of dealing with patients who suffer from various infections. Conducting investigations on the bacterial contamination of emergency ambulances play a crucial role to improve the occupational health of staff as well as the quality of patient care. Therefore, the aim of the present study was to investigate the presence of Staphylococcus aureus and other life treating bacteria in the urban and rural ambulances and their on-call emergency medical service personnel. Methods: This descriptive cross-sectional study was conducted on 12 front line pre-hospital emergency urban and rural ambulances in Kashan, Iran, in 2015. A total of 18 sites were sampled in each ambulance and from the nose of personnel. Grown colonies were confirmed based on colony morphology on mannitol salt agar plates, gram stain reaction and biochemical characteristics reactions. Results: The S. aureus contamination was only isolated from the nose of on-call emergency medical service providers of 12 urban and road ambulances, while no sign of contamination was found in 18 sampling sites of these front-line ambulances. Also, further evaluation of these sampling sites revealed the contamination with coagulase-negative staphylococci in all of them and oxygen tank was introduced as the most contaminated site inside the ambulances. Moreover, the prevalence of equipment contamination was significantly higher in urban ambulances. Conclusion: Identifying the rate of pathogens in clinical settings like the pre-hospital ambulance setting is an important issue which should be carefully considered. © 2020 The Author(s)

    Electrolysis of low-grade and saline surface water

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    Review Article Published: 17 February 2020 Electrolysis of low-grade and saline surface water Wenming Tong, Mark Forster, Fabio Dionigi, Sören Dresp, Roghayeh Sadeghi Erami, Peter Strasser, Alexander J. Cowan & Pau Farràs Nature Energy (2020)Cite this article 1779 Accesses 1 Citations 60 Altmetric Metricsdetails Abstract Powered by renewable energy sources such as solar, marine, geothermal and wind, generation of storable hydrogen fuel through water electrolysis provides a promising path towards energy sustainability. However, state-of-the-art electrolysis requires support from associated processes such as desalination of water sources, further purification of desalinated water, and transportation of water, which often contribute financial and energy costs. One strategy to avoid these operations is to develop electrolysers that are capable of operating with impure water feeds directly. Here we review recent developments in electrode materials/catalysts for water electrolysis using low-grade and saline water, a significantly more abundant resource worldwide compared to potable water. We address the associated challenges in design of electrolysers, and discuss future potential approaches that may yield highly active and selective materials for water electrolysis in the presence of common impurities such as metal ions, chloride and bio-organisms.W.T., M.F., R.S.E., A.J.C. and P.F. acknowledge financial support from INTERREG Atlantic Area programme (Grant reference EAPA_190_2016). P.F. acknowledges support from Royal Society Alumni programme. F.D., S.D. and P.S. gratefully acknowledge financial support by the German Research Foundation (DFG) through Grant reference number STR 596/8-1 and the federal ministry for economic affairs and energy (Bundesministerium für Wirtschaft und Energie, BMWi) under grant number 03EIV041F. P.S. acknowledges partial funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany´s Excellence Strategy – EXC 2008/1 – 390540038 (zum Teil gefördert durch die Deutsche Forschungsgemeinschaft (DFG) im Rahmen der Exzellenzstrategie des Bundes und der Länder – EXC 2008/1 – 390540038).peer-reviewed2020-08-1