1,756 research outputs found

    Besnoitia besnoiti infection alters both endogenous cholesterol de novo synthesis and exogenous LDL uptake in host endothelial cells

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    Besnoitia besnoiti, an apicomplexan parasite of cattle being considered as emergent in Europe, replicates fast in host endothelial cells during acute infection and is in considerable need for energy, lipids and other building blocks for offspring formation. Apicomplexa are generally considered as defective in cholesterol synthesis and have to scavenge cholesterol from their host cells for successful replication. Therefore, we here analysed the influence of B. besnoiti on host cellular endogenous cholesterol synthesis and on sterol uptake from exogenous sources. GC-MS-based profiling of cholesterol-related sterols revealed enhanced cholesterol synthesis rates in B. besnoiti-infected cells. Accordingly, lovastatin and zaragozic acid treatments diminished tachyzoite production. Moreover, increased lipid droplet contents and enhanced cholesterol esterification was detected and inhibition of the latter significantly blocked parasite proliferation. Furthermore, artificial increase of host cellular lipid droplet disposability boosted parasite proliferation. Interestingly, lectin-like oxidized low density lipoprotein receptor 1 expression was upregulated in infected endothelial hostcells, whilst low density lipoproteins (LDL) receptor was not affected by parasite infection. However, exogenous supplementations with non-modified and acetylated LDL both boosted B. besnoiti proliferation. Overall, current data show that B. besnoiti simultaneously exploits both, endogenous cholesterol biosynthesis and cholesterol uptake from exogenous sources, during asexual replication

    Valorização de resíduos plásticos na modificação de betumes para pavimentos rodoviários

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    Com o aumento do tráfego rodoviário são colocadas maiores exigências aos pavimentos, surgindo a necessidade de melhorar o seu desempenho. Um método que pode melhorar significativamente a qualidade dos pavimentos flexíveis é a adição de polímeros aos ligantes/misturas betuminosas. Assim, foram produzidos ligantes modificados com polímeros reciclados, em diferentes condições, cujo desempenho foi comparado com o de ligantes convencionais e de um ligante modificado comercial. Os resultados dos ensaios laboratoriais serão utilizados na seleção de resíduos plásticos e das condições de produção do betume modificado para otimizar o seu comportamento, salientando-se que este estudo procura promover a reutilização de resíduos de uma forma mais ecológica e económica.Financiado por Fundos FEDER através do Programa Operacional Fatores de Competitividade – COMPETE e por Fundos Nacionais através da FCT – Fundação para a Ciência e a Tecnologia no âmbito do projeto PLASTIROADS (PTDC/ECM/119179/2010) e do projeto estratégico UI 4047 – 2011-2012

    Utilization of waste materials to improve asphalt mixtures performance

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    This study aims to develop an innovative bitumen with large quantities of waste materials to improve asphalt mixtures performance. Different amounts of waste motor oil and waste HDPE were added to a new bitumen. The bitumen modified with 10% of waste motor oil and 5% of HDPE showed promising characteristics (high softening point temperatures and penetration slightly higher than the conventional bitumen). After the selection of the most promising modified bitumen, three asphalt mixtures were produced with different bitumens (namely conventional bitumen, commercial modified bitumen and the selected modified bitumen). Beyond that, this modified bitumen improved some mechanical characteristics of the asphalt mixture where it was used, in comparison to conventional and modified asphalt mixtures.Portuguese Government and EU/FSE within a PhD fellowship (SFRH/BD98379/2013) of the FCT, in the scope of POPH/QREN, by FEDER through the Competitiveness Factors Operational Programme (COMPETE) and by national funds through the Portuguese Foundation for Science and Technology (FCT) in the scope of PLASTIROAD Project (PTDC/ECM/119179/2010

    The Oesophageal Squamous Cell Carcinoma Cell Line COLO-680N Fails to Support Sustained Cryptosporidium parvum Proliferation

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    Cryptosporidium parvum is an important diarrhoea-associated protozoan, which is difficult to propagate in vitro. In 2017, a report described a continuous culture of C. parvum Moredun strain, in the oesophageal squamous cell carcinoma cell line COLO-680N, as an easy-to-use system for C. parvum propagation and continuous production of oocysts. Here, we report that—using the Köllitsch strain of C. parvum—even though COLO-680N cells, indeed, allowed parasite invasion and early asexual parasite replication, C. parvum proliferation decreased after the second day post infection. Considering recurring studies, reporting on successful production of newly generated Cryptosporidium oocysts in the past, and the subsequent replication failure by other research groups, the current data stand as a reminder of the importance of reproducibility of in vitro systems in cryptosporidiosis research. This is of special importance since it will only be possible to develop promising strategies to fight cryptosporidiosis and its ominous consequences for both human and animal health by a continuous and reliable methodological progress

    First Metabolic Insights into Ex Vivo Cryptosporidium parvum-Infected Bovine Small Intestinal Explants Studied under Physioxic Conditions

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    The apicomplexan Cryptosporidium parvum causes thousands of human deaths yearly. Since bovines represent the most important reservoir of C. parvum, the analysis of infected bovine small intestinal (BSI) explants cultured under physioxia offers a realistic model to study C. parvum–host cell–microbiome interactions. Here, C. parvum-infected BSI explants and primary bovine small intestinal epithelial cells were analysed for parasite development and metabolic reactions. Metabolic conversion rates in supernatants of BSI explants were measured after infection, documenting an immediate parasite-driven metabolic interference. Given that oxygen concentrations affect cellular metabolism, measurements were performed at both 5% O2 (physiological intestinal conditions) and 21% O2 (commonly used, hyperoxic lab conditions). Overall, analyses of C. parvum-infected BSI explants revealed a downregulation of conversion rates of key metabolites—such as glucose, lactate, pyruvate, alanine, and aspartate—at 3 hpi, followed by a rapid increase in the same conversion rates at 6 hpi. Moreover, PCA revealed physioxia as a driving factor of metabolic responses in C. parvum-infected BSI explants. Overall, the ex vivo model described here may allow scientists to address pending questions as to how host cell–microbiome alliances influence intestinal epithelial integrity and support the development of protective intestinal immune reactions against C. parvum infections in a realistic scenario under physioxic conditions

    Mechanical analysis of asphalt mixtures produced with waste plastic modified binders

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    This work compares the viscoelastic properties of an asphalt binder (70/100 pen) modified with different waste plastics and the mechanical properties of the resultant asphalt mixtures. Two different plastic wastes were used, namely recycled HDPE and EVA. Three different polymer modified binders were produced with these plastic wastes: i) 5% HDPE modified binder (P5); ii) 5% EVA modified binder (E5) and; iii) a modified binder with 4% of EVA and 2% HDPE (E4P2). Asphalt mixtures were produced with these modified binders, and their mechanical properties were analysed and compared with a conventional mixture produced with a 30/50 pen bitumen. It was possible to conclude that these recycled polymers are able to improve the mechanical performance of the asphalt mixtures used in road paving.FEDER funds through the Operational Programme for Competitiveness Factors & COMPETE and National Fund s through FCT & Foundation for Science and Technology under the project PLASTIROADS (PTDC/ECM/119179/2010) and Symposium_22 Recycling and Reuse of Wastes into New Composite Materials -2062-of the strategic project UI 4047- 2011-2012 Centre of Territory, Environment and Construction

    Compuestos fenólicos bioactivos y ácidos orgánicos en la decocción de frutos y hojas de Schinus areira L.

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    Se investigaron decocciones de hojas y frutos de Schinus areira L. del noroeste de Argentina. Compuestos fenólicos y ácidos orgánicos se analizaron mediante HPLC. Capacidad antioxidante e inhibición de α-glucosidasa se determinaron in vitro. Se evaluó toxicidad general con Artemia salina. Los principales compuestos fenólicos fueron hiperósido y ácido 3 O-cafeoilquínico en hojas y ácido gálico y catequina en frutos. Los principales ácidos orgánicos cuantificados fueron málico en hojas y cítrico en frutos. Ácido shikímico, precursor del Tamiflu está presente en decocción de frutos con un contenido relativamente importante. La de hojas presenta una mayor riqueza en compuestos bioactivos con actividad antirradicalaria frente a DPPH●, O2●- y ●NO. Las hojas y frutos de S. areira tenían una actividad inhibidora de la α-glucosidasa comparable a la de hiperósido y acarbosa. La decocción de frutas no fue eco-tóxica, pero sí la de hojas que podría ser fuente de compuestos bioactivos con actividad farmacológica.Leaf and fruit decoctions of Schinus areira L. from northwest Argentina were investigated here. Phenolic compounds and organic acids were analyzed by HPLC. Antioxidant capacity and αglucosidase inhibition were determined by using in vitro tests. The general toxicity was assessed against Artemia salina nauplii. Hyperoside and 3 O-caffeoylquinic acid in leaf decoctions; gallic acid and catechin in fruit decoction were the major phenolic compounds. Malic and citric acids were the main organic acid quantified in the leaf and fruit decoctions, respectively. Fruit decoction had a relatively important content of shikimic acid, precursor of Tamiflu. Leaf decoction presents a greater richness in bioactive compounds with antiradical activity against DPPH●, O2●- and ●NO radicals. S. areira leaves and fruits had α-glucosidase inhibitory activity comparable to hyperoside and acarbose. Fruit decoction was not eco-toxic; leaf decoction showed significant eco-toxic activity and could be chosen for the search of other bioactive compounds with pharmacological activity.Fil: Celaya, Liliana Soledad. Universidad Nacional de Misiones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Molina, Ana C.. Universidad Nacional de Jujuy. Facultad de Ingeniería; ArgentinaFil: Gonzalez, Adriana M.. Universidad Nacional de Jujuy. Facultad de Ingeniería; ArgentinaFil: Villa, Walter Cosme. Universidad Nacional de Jujuy. Facultad de Ingeniería; ArgentinaFil: Silva, Luis R.. Universidad de Porto; PortugalFil: Viturro, Carmen Ines. Universidad Nacional de Jujuy. Facultad de Ingeniería; Argentin

    Host-Tailored Sensors for Leucomalachite Green Potentiometric Measurements

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    A new biomimetic sensor for leucomalachite green host-guest interactions and potentiometric transduction is presented. The artificial host was imprinted in methacrylic acid or acrylamido-2-methyl-1-propanesulfonic acid-based polymers. Molecularly imprinted particles were dispersed in 2-nitrophenyloctyl ether and trapped in poly(vinyl chloride). The potentiometric sensors exhibited a near-Nernstian response in steady state evaluations, with slopes and detection limits ranging from 45.8 to 81.2 mV and 0.28 to 1.01 , respectively. They were independent from the pH of test solutions within 3 to 5. Good selectivity was observed towards drugs that may contaminate water near fish cultures, such as oxycycline, doxycycline, enrofloxacin, trimethoprim, creatinine, chloramphenicol, and dopamine. The sensors were successfully applied to field monitoring of leucomalachite green in river samples. The method offered the advantages of simplicity, accuracy, applicability to colored and turbid samples, and automation feasibility

    Fasciola hepatica soluble antigens (FhAg) induce ovine PMN innate immune reactions and NET formation in vitro and in vivo

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    [EN] Fasciola hepatica causes liver fluke disease, a worldwide neglected and re-emerging zoonotic disease, leading to hepatitis in humans and livestock. In the pathogenesis, flukes actively migrate through liver parenchyma provoking tissue damage. Here, parasites must confront leukocytes of the innate immune system in vivo. Polymorphonuclear neutrophils (PMN) are the most abundant granulocytes and first ones arriving at infection sites. PMN may display neutrophil extracellular traps (NETs), consisting of nuclear DNA, decorated with histones, enzymes, and antimicrobial peptides. We investigated for the first time whether F. hepatica soluble antigens (FhAg) can also trigger NETosis and innate immune reactions in exposed ovine PMN. Thus, isolated PMN were co-cultured with FhAg and NET formation was visualized by immunofluorescence and scanning electron microscopy analyses resulting in various phenotypes with spread NETs being the most detected in vitro. In line, NETs quantification via Picogreen®-fluorometric measurements revealed induction of anchored- and cell free NETs phenotypes. Live cell 3D-holotomographic microscopy revealed degranulation of stimulated PMN at 30 min exposure to FhAg. Functional PMN chemotaxis assays showed a significant increase of PMN migration (p = 0.010) and intracellular ROS production significantly increased throughout time (p = 0.028). Contrary, metabolic activities profiles of FhAg-exposed PMN did not significantly increase. Finally, in vivo histopathological analysis on F. hepatica-parasitized liver tissue sections of sheep showed multifocal infiltration of inflammatory cells within liver parenchyma, and further fluorescence microscopy analyses confirmed NETs formation in vivo. Overall, we hypothesized that NET-formation is a relevant host defence mechanism that might have a role in the pathogenesis of fasciolosis in vivo.SIOpen Access funding enabled and organized by Projekt DEAL. The study was funded by Agencia Nacional de Investigación y Desarrollo (ANID) Fondecyt Initiation 2020 number 11200103 entitled “Analysis ofFasciola hepatica-induced extracellular traps formation in sheep: implications of this innate immune reaction in the pathogenesis of liver fluke disease” held by TM
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