Lipid-free Antigen B subunits from echinococcus granulosus: oligomerization, ligand binding, and membrane interaction properties

Background: The hydatid disease parasite Echinococcus granulosus has a restricted lipid metabolism, and needs to harvest essential lipids from the host. Antigen B (EgAgB), an abundant lipoprotein of the larval stage (hydatid cyst), is thought to be important in lipid storage and transport. It contains a wide variety of lipid classes, from highly hydrophobic compounds to phospholipids. Its protein component belongs to the cestode-specific Hydrophobic Ligand Binding Protein family, which includes five 8-kDa isoforms encoded by a multigene family (EgAgB1-EgAgB5). How lipid and protein components are assembled into EgAgB particles remains unknown. EgAgB apolipoproteins self-associate into large oligomers, but the functional contribution of lipids to oligomerization is uncertain. Furthermore, binding of fatty acids to some EgAgB subunits has been reported, but their ability to bind other lipids and transfer them to acceptor membranes has not been studied.<p></p> Methodology/Principal Findings: Lipid-free EgAgB subunits obtained by reverse-phase HPLC were used to analyse their oligomerization, ligand binding and membrane interaction properties. Size exclusion chromatography and cross-linking experiments showed that EgAgB8/2 and EgAgB8/3 can self-associate, suggesting that lipids are not required for oligomerization. Furthermore, using fluorescent probes, both subunits were found to bind fatty acids, but not cholesterol analogues. Analysis of fatty acid transfer to phospholipid vesicles demonstrated that EgAgB8/2 and EgAgB8/3 are potentially capable of transferring fatty acids to membranes, and that the efficiency of transfer is dependent on the surface charge of the vesicles.<p></p> Conclusions/Significance: We show that EgAgB apolipoproteins can oligomerize in the absence of lipids, and can bind and transfer fatty acids to phospholipid membranes. Since imported fatty acids are essential for Echinococcus granulosus, these findings provide a mechanism whereby EgAgB could engage in lipid acquisition and/or transport between parasite tissues. These results may therefore indicate vulnerabilities open to targeting by new types of drugs for hydatidosis therapy.<p></p&gt

The effect of competition on manager's compensation : evidence from a quasi-natural experiment

This paper studies the effect of competition on executive compensation. We estimate the effect of increased product market competition on the performance-pay sensitivity of CEOs, and contrast it with the effect for department managers and other workers in the corporation. We use a recent reform that simplied firm entry regulation in Portugal as a quasi-natural experiment. The empirical strategy exploits the staggered implementation of the reform across municipalities. Using linked employer-employee data for the universe of workers and firms, we show that increased product market competition, following the deregulation, decreased the sensitivity of pay to performance of CEOs and other managers, with no significant effects found for other workers. These findings are consistent with existing theoretical results in a principal-agent framework that a fall in entry costs leads to weaker managerial incentives.Fundação para a Ciência e a Tecnologia through the Applied Microeconomics Research Unit, award no. PEst-OE/EGE/UI3181/2014. Portuguese Ministry of Labor and Social Solidarity and the O¢ce for National Statistics (INE

Chitosan/sulfated locust bean gum nanoparticles: In vitro and in vivo evaluation towards an application in oral immunization

This work proposes the design of nanoparticles based on locus bean gum (LBG) and chitosan to be used as oral immunoadjuvant for vaccination purposes. LBG-based nanoparticles were prepared by mild polyelectrolyte complexation between chitosan (CS) and a synthesized LBG sulfate derivative (LBGS). Morphological characterization suggested that nanoparticles present a solid and compact structure with spherical-like shape. Sizes around 180-200 nm and a positive surface charge between +9 mV and +14 mV were obtained. CS/LBGS nanoparticles did not affect cell viability of Caco-2 cells after 3 h and 24h of exposure when tested at concentrations up to 1.0 mg/mL. Two model antigens (a particulate acellular extract HE of Salmonella enterica serovar Enteritidis, and ovalbumin as soluble antigen) were associated to CS/LBGS nanoparticles with efficiencies around 26% for ovalbumin and 32% for HE, which resulted in loading capacities up to 12%. The process did not affect the antigenicity of the associated antigens. BALB/c mice were orally immunized with ovalbumin-loaded nanoparticles (100 mu g), and results indicate an adjuvant effect of the CS/LBGS nanoparticles, eliciting a balanced Th1/Th2 immune response. Thus, CS/LBGS nanoparticles are promising as antigen mucosal delivery strategy, with particular interest for oral administration. (C) 2017 Elsevier B.V. All rights reserved.National Portuguese funding through FCT- Fundacao para a Ciencia e a Tecnologia, project [PTDC/SAU-FCF/100291/2008, PEst-OE/EQB/LA0023/2011]FEDER - Fundo Europeu de Desenvolvimento RegionalPortuguese funds through FCT - Fundacao para a Ciencia e a Tecnologia/Ministerio da Cienci

Papel de nano-aditivos na funcionalização de argamassas

A manutenção da qualidade do ar no interior dos edifícios é um dos aspetos mais relevantes da construção sustentável e tem forte impacto no nível de conforto dos utilizadores. A introdução de nano-aditivos em materiais de construção permite modificar propriedades fundamentais destes materiais convencionais, com o objetivo de proporcionar novas funcionalidades. Neste trabalho apresentam-se os resultados obtidos com o desenvolvimento de argamassas funcionais que pretendem melhorar a qualidade do ar interior e contribuir para a poupança energética dos edifícios. As formulações foram optimizadas com vista à sua aplicação em construção nova ou reabilitação

Herbal beverages formulations and bioactive properties: a comparative study.

Herbal beverages are among the main products which claim medicinal benefits, specially related with antioxidant properties [1,2]. The definition of herbal beverages (“teas”) as functional drinks might be related with the plant species from which is prepared, formulation or preparation method. In this study the beverages were prepared from Camellia sinensis (black and green tea), Aspalathus linearis (red tea) and Cochlospermum angolensis (borututu tea), available in different formulations (bags, leaves, roots, granulates, powders or liquids), after infusion, solubilisation or by simple direct use. Further than single plants, some mixtures composed by different fruits, plants or algae extracts were also evaluated. For a better understanding of the bioactive potential of these products, the DF50 (dilution factor responsible for 50% of antioxidant activity, AA) was calculated for all the AA assays (scavenging effects, reducing power and lipid peroxidation inhibition). Linear discriminant analysis was used to categorize tea formulations according with their AA and antioxidant compounds

Insights on the formulation of herbal beverages with medicinal claims according with their antioxidant properties

Several herbal beverages claim medicinal benefits due to their antioxidant properties. However, operational factors such as the extracted herbal component, preparation method or concentration levels, might influence their biological activity. To assess this effect, the antioxidant activity of beverages prepared with Camellia sinensis, Aspalathus linearis or Cochlospermum angolensis, used solely or mixed with different fruit, plant or algae extracts, was studied using different formulations (bags, leaves, roots, granulates, powders, liquids) and different preparation methods (infusion, solubilisation or promptly used). The DF50 (dilution factor responsible for 50% of antioxidant activity) values were calculated to compare their antioxidant activity. A linear discriminant analysis was used to categorize the assayed samples according to their antioxidant activity and bioactive molecules profiles. The results indicated that antioxidant activity and antioxidant compounds are significantly affected by formulation and preparation method, but overall the labelled antioxidant benefits were validated. Green tea showed the highest activity, but with different behaviour within each used formulation. The high DF50 values calculated for some products might be used to adjust the dietary dose or formulation, preventing also putative pro-oxidant effects. Hence, the obtained results might be useful to define the formulation of these highly consumed herbal beverages, enhancing their health effects.Portuguese Foundation for Science and Technology (FCT) and to Mountain Research Center. J.C.M. Barreira thanks to FCT, Human Potential Operational Programme- National Strategic Reference Framework (POPH-QREN) and FSE for his grant (SFRH/BPD/72802/2010)

Comparative study of antioxidant properties of different green tea formulations.

Tea, a product made up from leaf and bud of the plant Camellia sinensis, is, after water, the most consumed drink in the world. Particularly, green tea, a “non-fermented” tea (produced by drying and steaming the fresh leaves to inactivate the polyphenol oxidase and thus, non oxidation occurs) has been related to different health benefits such as reduction in the risk of cardiovascular disease and some forms of cancer, and neuroprotective power, as well as other disorders related to oxidative stress. Moreover, it was suggested the ability of green tea, when consumed within a balanced controlled diet, to improve overall the antioxidative status and to protect against oxidative damage in humans [1]

Textile-based pressure sensors for step detection: a preliminary assessment

This paper presents the development and performance assessment of textile-based sensor based on a three layer architecture for the step detection. Two different transducing elements (EeonTex™ LG-SLPA and velostat) and electrodes (Satatex Techniktex P-130 and Elitex yarns) were selected for the construction of the sensors. The performance of the resulting sensors was assessed based on a dynamometer cyclic compression/decompression test with different compressions loads and at different speeds. Additionally, a real-life experiment was conducted to evaluate the sensor response during walking. The results show that all sensors configurations have a non-linear resistance-force relation. The best sensor configuration for the step detection was the combination of EeonTex™ LG-SLPA as a transducing element and the Elitex yarns for the electrodes. In this configuration, the resistance magnitude varies in an order of hundreds of kohms between the stance and the swing phases.This work was partially financed by FEDER funds through the Competitively Factors Operational Programme—COMPETE and by national founds through FCT -Foundation for Science and Technology within the scope of Project POCI-01-0145-FEDER-007136 and Project PEstOE/EEI/UI0319/2014. Authors would like to thanks André Paiva and Sérgio Branco for their collaboration in sensors production and data acquisition, respectively.info:eu-repo/semantics/publishedVersio

Fabrication of calcium phosphates with controlled properties using a modular oscillatory flow reactor

Several technologies and synthesis routes have been implemented to produce calcium phosphates (CaPs) with distinct characteristics for biomedical applications. However, produce CaPs in a controlled way still represents a challenge. Oscillatory flow reactors (OFRs) are a technology ready to deliver in terms of mixing intensification in multiphase systems. In particular, continuous processes in OFRs improve control over the reaction conditions and can be implemented at an industrial scale. The aim of this work was to study for the first time the influence of the oscillation amplitude (x0: 4, 8 and 18 mm) and frequency (f: 1.9, 4 and 6 Hz) as well as residence time (τ: 3.3, 6.6 min) on the final CaP particles’ physicochemical properties using a continuous precipitation process in a novel modular oscillatory flow plate reactor (MOFPR). Furthermore, other parameters such as the initial reagents concentration, initial Ca/P molar ratio (Ca/P = 1.67, 1.33) and temperature (T = 37, 54 ºC) were also assessed. The synthesized particles and overall process were compared with particles obtained using the same methodology in conventional reactors, evidencing the potential of this technology to fabricate CaPs with tailored properties for potential application as nano or microcarriers for biomedical applications.info:eu-repo/semantics/publishedVersio

Motility assessment of the ciliated tetrahymena pyriformis after exposition to toxic compounds using image analysis

PRAXIS XXI