22 research outputs found

    CCR2- and Flt3-Dependent Inflammatory Conventional Type 2 Dendritic Cells Are Necessary for the Induction of Adaptive Immunity by the Human Vaccine Adjuvant System AS01

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    The Adjuvant System AS01 contains monophosphoryl lipid A (MPL) and the saponin QS-21 in a liposomal formulation. AS01 is included in recently developed vaccines against malaria and varicella zoster virus. Like for many other adjuvants, induction of adaptive immunity by AS01 is highly dependent on the ability to recruit and activate dendritic cells (DCs) that migrate to the draining lymph node for T and B cell stimulation. The objective of this study was to more precisely address the contribution of the different conventional (cDC) and monocyte-derived DC (MC) subsets in the orchestration of the adaptive immune response after immunization with AS01 adjuvanted vaccine. The combination of MPL and QS-21 in AS01 induced strong recruitment of CD26+XCR1+ cDC1s, CD26+CD172+ cDC2s and a recently defined CCR2-dependent CD64-expressing inflammatory cDC2 (inf-cDC2) subset to the draining lymph node compared to antigen alone, while CD26-CD64+CD88+ MCs were barely detectable. At 24 h post-vaccination, cDC2s and inf-cDC2s were superior amongst the different subsets in priming antigen-specific CD4+ T cells, while simultaneously presenting antigen to CD8+ T cells. Diphtheria toxin (DT) mediated depletion of all DCs prior to vaccination completely abolished adaptive immune responses, while depletion 24 h after vaccination mainly affected CD8+ T cell responses. Vaccinated mice lacking Flt3 or the chemokine receptor CCR2 showed a marked deficit in inf-cDC2 recruitment and failed to raise proper antibody and T cell responses. Thus, the adjuvant activity of AS01 is associated with the potent activation of subsets of cDC2s, including the newly described inf-cDC2s

    Aphid herbivory as a potential driver of primary succession in coastal dunes

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    Herbivory is a major factor affecting both the performance and the fitness of the species composing a plant community and, ultimately, conditioning its temporal and spatial dynamics. Coastal dunes are a typical example of primary succession where different biotic and abiotic factors determine plant species occurrence; however, the effect of insect herbivory herein has remained little explored. To address this matter, we combined an observational study along a successional gradient with a green-house experiment to determine the occurrence and the impact of plant-aphid interactions. We focused on the species Schizaphis rufula, a widespread and abundant aphid associated with dune grasses in early stages of primary succession in Europe. Firstly, we studied aphid infestation rates on the dune grass Ammophila arenaria along a succession gradient in three locations of the North Sea coast to address the relationship between plant community composition and aphid occurrence; secondly, we tested the effect of aphid herbivory on a set of dune species typical for the different stages of succession. We found that the degree of aphid infestation was inversely correlated with the degree of dune fixation. The results of the experiment showed that aphid multiplication was significantly higher and its effect more pronounced on two early successional grass species, i.e. A. arenaria and Leymus arenarius. Here aphid multiplication resulted in a severe decrease in plant biomass; in late successional grass species, there was limited multiplication and no effect on biomass. The results of the field survey and the green-house experiment indicate that aphids show a clear preference for plants from early successional stages and, moreover, they have a greater impact on these plant species. All this supports the hypothesis of aphid herbivory as a driving factor of primary succession in coastal dunes

    Effect of organic P forms and P present in inorganic colloids on the determination of dissolved P in environmental samples by the diffusive gradient in thin films technique, ion chromatography, and colorimetry

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    The speciation of P in environmental samples is operationally defined, since it depends on the analytical method used. In this study, we compared four methods to measure P in solution: ion chromatography (IC), the malachite green colorimetric method (CM), the diffusive gradient in thin films technique (DGT) and, for total dissolved P, optical inductively coupled plasma (ICP). These methods were compared on three sets of solutions (filtered over <0.45 μm): solutions with model organic P compounds, suspensions of synthesized inorganic Fe and Al colloids loaded with P, and environmental samples. The environmentally relevant organic P compounds were only marginally detected by CM and IC. Substantial fractions of certain organic P compounds contributed to the DGT measurement. Colorimetric analysis of DGT eluates detected in general less P than ICP analysis, indicating that these organic P compounds sorbed on the zero sink layer. Phosphorus associated with inorganic colloids was completely recovered by CM, but not by IC and least by DGT. Measurements on a wide set of 271 environmental samples (soil pore waters, groundwaters, and surface waters) suggest that surface water P is largely present as orthophosphate and phosphate sorbed onto inorganic colloids, whereas organic P contributes more in groundwaters.Christoff Van Moorleghem, Laetitia Six, Fien Degryse, Erik Smolders, and Roel Merck

    Indole alkaloids XVII: Five dihydroindole alkaloids from Aspidosperma verbascifolium

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    A study of Aspidosperma verbascifolium has led to the isolation of four known dihydroindole alkaloids: kopsanone [I], kopsanol [II], 3'‐epikopsanol [III], 10‐oxo‐3'‐epikopsanol [IV] and a new natural product: Nα‐formylkopsanol [VII]. Copyright © 1969 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Disentangling cognition and emotion in older adults: the role of cognitive control and mental health in emotional conflict adaptation

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    Recent research suggests cognition has a bidirectional relationship with emotional processing in older adults, yet the relationship is still poorly understood. We aimed to examine a potential relationship between late-life cognitive function, mental health symptoms, and emotional conflict adaptation. We hypothesized that worse cognitive control abilities would be associated with poorer emotional conflict adaptation. We further hypothesized that a higher severity of mental health symptoms would be associated with poorer emotional conflict adaptation.Participants included 83 cognitively normal community-dwelling older adults who completed a targeted mental health and cognitive battery, and emotion and gender conflict-adaptation tasks.Consistent with our hypothesis, poorer performance on components of cognitive control, specifically attention and working memory, was associated with poorer emotional conflict adaptation. This association with attention and working memory was not observed in the non-affective-based gender conflict adaptation task. Mental health symptoms did not predict emotional conflict adaptation, nor did performance on other cognitive measures.Our findings suggest that emotion conflict adaptation is disrupted in older individuals who have poorer attention and working memory. Components of cognitive control may therefore be an important potential source of inter-individual differences in late-life emotion regulation and cognitive affective deficits. Copyright © 2016 John Wiley & Sons, Ltd

    The Ti-Ni-Me and Cu-Al-Me melt-spun shape memory ribbons: Relation between the microstructure and functional properties

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    A series of the Ti-Ni-Me (Me: Cu, Co, Zr, Hf, Re) and Cu-Al-Me (Me: Ni, Mn, Ti, Nb) rapidly solidified ribbons have been produced by a planar flow casting. Calorimetric and thermomechanical investigations as well as XRD, TEM/SAD and metallography observations have been performed. The martensitic transformation characteristics of the ribbons are studied and compared to those of bulk samples. The functional propel-ties have been measured for unidirectional deformation in cooling/heating cycles under a fixed load (the shape memory schema), and in tension at fixed temperature and subsequent heating/cooling stages (the superelastic, shape memory and I eversion stress schemes). Microstructure features and their influence on the martensitic transformation are analyzed with respect to the variation of functional properties.status: publishe

    CCR2-and Flt3-Dependent Inflammatory Conventional Type 2 Dendritic Cells Are Necessary for the Induction of Adaptive Immunity by the Human Vaccine Adjuvant System AS01

    No full text
    The Adjuvant System AS01 contains monophosphoryl lipid A (MPL) and the saponin QS-21 in a liposomal formulation. AS01 is included in recently developed vaccines against malaria and varicella zoster virus. Like for many other adjuvants, induction of adaptive immunity by AS01 is highly dependent on the ability to recruit and activate dendritic cells (DCs) that migrate to the draining lymph node for T and B cell stimulation. The objective of this study was to more precisely address the contribution of the different conventional (cDC) and monocyte-derived DC (MC) subsets in the orchestration of the adaptive immune response after immunization with AS01 adjuvanted vaccine. The combination of MPL and QS-21 in AS01 induced strong recruitment of CD26+XCR1+ cDC1s, CD26+CD172+ cDC2s and a recently defined CCR2-dependent CD64-expressing inflammatory cDC2 (inf-cDC2) subset to the draining lymph node compared to antigen alone, while CD26-CD64+CD88+ MCs were barely detectable. At 24 h post-vaccination, cDC2s and inf-cDC2s were superior amongst the different subsets in priming antigen-specific CD4+ T cells, while simultaneously presenting antigen to CD8+ T cells. Diphtheria toxin (DT) mediated depletion of all DCs prior to vaccination completely abolished adaptive immune responses, while depletion 24 h after vaccination mainly affected CD8+ T cell responses. Vaccinated mice lacking Flt3 or the chemokine receptor CCR2 showed a marked deficit in inf-cDC2 recruitment and failed to raise proper antibody and T cell responses. Thus, the adjuvant activity of AS01 is associated with the potent activation of subsets of cDC2s, including the newly described inf-cDC2s

    The dissociation kinetics of Cu-dissolved organic matter complexes from soil and soil amendments

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    Complexes between dissolved organic matter (DOM) and copper (Cu) that dissociate very slowly can theoretically facilitate Cu leaching to the groundwater. Data on dissociation kinetics of Cu-DOM complexes present in soil and in soil amendments are limited. The dissociation kinetics of different Cu-DOM complexes from soil, wastewater, pig manure and sewage sludge was measured with the Competitive Ligand Exchange Method (CLEM) and Diffusive Gradient in Thin films (DGT) technique. The solutions were set at constant pH, Ca concentration and free Cu(2+) activity to allow comparison between the different samples. The average dissociation rate constant k(d) of the complexes, as measured by CLEM, was about 10(-3) s(-1) and the fractions of dissolved Cu that were undissociated after 8 h ranged from <1% to 25%. These fractions determined by CLEM were significantly correlated with the non-labile fractions (0-82%) determined in the DGT tests and data analysis show that DGT data can be predicted from CLEM data. The dissociation rates decreased when Cu-DOM complexes had been equilibrated at lower Cu(2+) activities. Increasing the Cu-DOM contact time (7-297 days) decreased the dissociation rate. The non-labile fractions were positively correlated with the specific UV absorbance suggesting that aromatic moieties in DOM hold non-labile Cu. All natural Cu-DOM complexes contained a detectable fraction with a dissociation rate constant k(d) lower than 10(-5)s(-1) which can theoretically lead to non-equilibrium conditions and leaching risks in soil.F. Amery, F. Degryse, C. Van Moorleghem, M. Duyck and E. Smolder
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