References of "Deleu, Magali"
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See detailD-Xylose and L-arabinose laurate esters: Enzymatic synthesis, characterization and physico-chemical properties
Méline, Thomas; Muzard, Murielle; Deleu, Magali ULiege et al

in Enzyme and Microbial Technology (2018), 112

Efficient enzymatic synthesis of D-xylose and L-arabinose lauryl mono- and diesters has been achieved by transesterification reactions catalysed by immobilized Candida antarctica lipase B as biocatalyst, in ... [more ▼]

Efficient enzymatic synthesis of D-xylose and L-arabinose lauryl mono- and diesters has been achieved by transesterification reactions catalysed by immobilized Candida antarctica lipase B as biocatalyst, in organic medium in the presence of D-xylose or L-arabinose and vinyllaurate at 50°C. In case of L-arabinose, one monoester and one diester were obtained in a 57% overall yield. A more complex mixture was produced for Dxylose as two monoesters and two diesters were synthesized in a 74.9% global yield. The structures of all these pentose laurate esters was solved. Results demonstrated that the esterification first occurred regioselectively onto the primary hydroxyl groups. Pentose laurate esters exhibited interesting features such as low critical aggregation concentrations values all inferior to 25μM. Our study demonstrates that the enzymatic production of L-arabinose and D-xylose-based esters represents an interesting approach for the production of green surfactants from lignocellulosic biomass-derived pentoses. [less ▲]

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See detailSurfactin protects wheat against Zymoseptoria tritici and activates both salicylic acid- and jasmonic acid-dependent defense responses
Le Mire, Géraldine ULiege; Siah, Ali; Brisset, Marie-Noëlle et al

in Agriculture (2018), 8

Natural elicitors induce plant resistance against a broad spectrum of diseases, and are currently among the most promising biocontrol tools. The present study focuses on the elicitor properties of the ... [more ▼]

Natural elicitors induce plant resistance against a broad spectrum of diseases, and are currently among the most promising biocontrol tools. The present study focuses on the elicitor properties of the cyclic lipopeptide surfactin on wheat, in order to stimulate the defenses of this major crop against the challenging fungal pathogen Zymoseptoria tritici. The protection efficacy of surfactin extracted from the strain Bacillus amyloliquefaciens S499 was investigated through greenhouse trials. Surfactin protected wheat by 70% against Z. tritici, similarly to the chemical reference elicitor Bion®50WG. In vitro biocidal assays revealed no antifungal activities of surfactin towards the pathogen. A biomolecular RT-qPCR based low-density microarray tool was used to study the relative expression of 23 wheat defense genes. Surfactin significantly induced wheat natural defenses by stimulating both salicylic acid- and jasmonic acid-dependent signaling pathways. Surfactin was successfully tested as an elicitor on the pathosystem wheat–Z. tritici. These results promote further sustainable agricultural practices and the reduction of chemical inputs. [less ▲]

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See detailCould saponins be used to enhance bioremediation of polycyclic aromatic hydrocarbons in aged-contaminated soils ?
Davin, Marie ULiege; Starren, Amandine; Deleu, Magali ULiege et al

in Chemosphere (2018), 194

Polycyclic aromatic hydrocarbons (PAH) are persistent organic compounds of major concern that tend to accumulate in the environment, threatening ecosystems and health. Brownfields represent an important ... [more ▼]

Polycyclic aromatic hydrocarbons (PAH) are persistent organic compounds of major concern that tend to accumulate in the environment, threatening ecosystems and health. Brownfields represent an important tank for PAHs and require remediation. Researches to develop bioremediation and phytoremediation techniques are being conducted as alternatives to environmentally aggressive, expensive and often disruptive soil remediation strategies. The objectives of the present study were to investigate the potential of saponins (natural surfactants) as extracting agents and as bioremediation enhancers on an aged-contaminated soil. Two experiments were conducted on a brownfield soil containing 15 PAHs. In a first experiment, soil samples were extracted with saponins solutions (0; 1; 2; 4 and 8 g.L-1). In a second experiment conducted in microcosms (28°C), soil samples were incubated for 14 or 28 days in presence of saponins (0; 2.5 and 5 mg.g- 1). CO2 emissions were monitored throughout the experiment. After the incubation, dehydrogenase activity was measured as an indicator of microbiological activity and residual PAHs were determined. In both experiments PAHs were determined using High-Performance Liquid Chromatography and Fluorimetric Detection. The 4 g.L-1 saponins solution extracted significantly more acenaphtene, fluorene, phenanthrene, anthracene, and pyrene than water. PAHs remediation was not enhanced in presence of saponins compared to control samples after 28 days. However CO2 emissions and dehydrogenase activities were significantly more important in presence of saponins, suggesting no toxic effect of these surfactants towards soil microbiota. [less ▲]

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See detailStructural Basis for Plant Plasma Membrane Protein Dynamics and Organization into Functional Nanodomains
Gronnier, Julien; Crowet, Jean-Marc ULiege; Habenstein, Birgit et al

in eLife (2017), 6

Plasma Membrane is the primary structure for adjusting to ever changing conditions. PM sub-compartmentalization in domains is thought to orchestrate signalling cascades. Yet, mechanisms governing membrane ... [more ▼]

Plasma Membrane is the primary structure for adjusting to ever changing conditions. PM sub-compartmentalization in domains is thought to orchestrate signalling cascades. Yet, mechanisms governing membrane organization are mostly uncharacterized. The plant-specific proteins REMORINs are factors regulating hormonal crosstalk and host invasion. REMs are the best-characterized PM nanodomain markers targeted to the PM via an uncharacterized moiety called REMORIN C-terminal Anchor. By coupling biophysical methods, super-resolution microscopy and physiology, we decipher an original mechanism regulating the dynamic and organization of nanodomains. We showed that PM targeting is independent of the COP II-dependent secretory pathway and mediated by PI4P and sterol. REM-CA is an unconventional lipid-binding motif that confers nanodomain organization. Analyses of REM-CA mutants by single particle tracking demonstrate that mobility and supramolecular organization are critical for immunity. This study provides a unique mechanistic insight into how the tight control of spatial segregation is critical in the definition of PM domain necessary to support biological function. [less ▲]

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See detailSynthetic Rhamnolipid Bolaforms (SRBs) as inducers of plant innate immunity
Luzuriaga-Loaiza, Patricio ULiege; Schellenberger, Romain; Touchard, Matthieu et al

Conference (2017, June 28)

Natural and synthetic elicitors have demonstrated a high potential for a more sustainable agriculture and the control of plant diseases via the induction of plant defense responses. Microbial ... [more ▼]

Natural and synthetic elicitors have demonstrated a high potential for a more sustainable agriculture and the control of plant diseases via the induction of plant defense responses. Microbial biosurfactants like surfactin (Bacillus spp.) and rhamnolipids (Pseudomonas spp.) have recently been shown to stimulate the plant innate immune system. Unlike canonical elicitors exemplified by bacterial flagellin, some data suggest that surfactin and rhamnolipid perception do not depend on the presence of specific receptors in the plant cell but rather on the direct interaction of the molecules with the lipid phase of the plant plasma membrane. Moreover, surfactin and rhamnolipid interactions with plant cells are thought to depend on their amphipathicity and the length of their acyl chain. In an attempt to mimic the efficacy of these natural biosurfactants, we have synthesized via green chemistry new bio-inspired amphiphilic elicitors. In this work, we present the characterization of Arabidopsis innate immunity in response to synthetic rhamnolipid bolaforms (SRBs) with variable acyl chain lengths. Using an original pluridisciplinary approach that covers biophysical and biological assays, we assessed the capacity of SRBs to interact with plasma membranes and to stimulate defense responses in Arabidopsis thaliana. Our results show that SRBs, depending on the acyl chain length, differentially activated early and late immunityrelated signaling events, defense gene expression and cell death. Moreover, we have demonstrated that an unsaturated SRB containing a C14 acyl chain is effective to induce local resistance against the hemibiotrophic bacteria Pseudomonas syringae pv. tomato. The biophysical studies suggest that a direct interaction of the SRB C14 with the plasma membrane lipids would be involved in the plant perception and induction of plant immunity. [less ▲]

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See detailPlant oxylipins: structure-function relationship
Genva, Manon ULiege; Andersson, Mats X.; Nasir, Mehmet Nail ULiege et al

Conference (2017, May 09)

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See detailComplementary biophysical tools to investigate lipid specificity in the interaction between bioactive peptides and the plasma membrane
Deleu, Magali ULiege; Lins, Laurence ULiege

Conference (2017, March)

Plasma membranes are complex entities common to all living cells. The basic principle of their organization appears very simple, but they are actually of high complexity and represent very dynamic ... [more ▼]

Plasma membranes are complex entities common to all living cells. The basic principle of their organization appears very simple, but they are actually of high complexity and represent very dynamic structures. The interactions between bioactive molecules notably peptides, and lipids are important for numerous processes, from drug bioavailability to viral fusion. The cell membrane is a carefully balanced environment and any changes inflicted upon its structure by a bioactive peptide must be considered in conjunction with the overall effect that this may have on the function and integrity of the membrane. As a general concept, understanding the mechanism at the molecular level by which bioactive molecules interact with cell membranes is of fundamental importance. Lipid specificity is a key factor for the detailed understanding of the penetration and/or activity of lipid-interacting peptides and of mechanisms of some diseases. Further investigation in that way should improve drug discovery and development of membrane-active molecules in many domains such as health, plant protection or microbiology. In this talk, we propose to overview some complementary “in vitro” and “in silico” biophysical approaches that can give information about lipid specificity at a molecular point of view. Our strategy is illustrated on different bioactive peptides such as antimicrobial peptides, peptides involved in human diseases or in plant cell signalling. [less ▲]

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See detailUse of complementary biophysical approaches to study the interactions of fatty acid hydroperoxides with biomimetic plant plasma membranes
Deboever, Estelle ULiege; Nasir, Mehmet Nail ULiege; Deleu, Magali ULiege et al

Poster (2017, January 20)

In the actual context, biopesticides have emerged as a main alternative to conventional agriculture1. Hence, elicitors are metabolites naturally produced by microorganisms, pathogenic or not, and plants ... [more ▼]

In the actual context, biopesticides have emerged as a main alternative to conventional agriculture1. Hence, elicitors are metabolites naturally produced by microorganisms, pathogenic or not, and plants which are able to induce the natural resistance of plants. Also, they have proved to be excellent candidates for biological control. In this context, the lipoxygenase pathway leads to the formation of fatty acid degradation products, called oxylipins, which appear to be crucial agents in plant defence mechanisms2,3. Moreover, with their broad spectrum of action and their possible inducibility, oxylipins appear to be promising candidates for their use as elicitors4. This work focuses on two hydroperoxy-derived oxylipins, the 13(S)-hydroperoxy-octadecadienoic acid (13-HPOD) and the 13(S)-hydroperoxy-octadecatrienoic acid (13-HPOT). The study of the interaction of such compounds with representative plant plasma membrane lipids is essential to understand plant resistance mechanisms. Several in silico and experimental techniques of biophysics showed that acyl-hydroperoxides have significant adsorption capacity and a strong affinity for model membranes. They may also penetrate biological membrane but no permeabilisation effect was observed in this work. Slight conformational differences seem to have a significant impact on their ability to interact with plant plasma membranes. Based on these results, further investigation of the interactions of fatty acids hydroperoxides, even more on the 9-forms, with plant plasma membranes and eventually in the presence of phytopathogenic species, would allow a better understanding of the innate immunity and, on the longer term, could lead to the development of new elicitors with biological mechanisms potentially independent of membrane protein receptors. [less ▲]

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See detailEudicot plant-specific sphingolipids determine host selectivity of microbial NLP cytolysins
Lenarcic, Tea; Albert, Isabell; Bohm, Hannah et al

in Science (2017), 358

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See detailHemicelluloses and Lignin in Biorefineries
wertz, Jean-Luc; Deleu, Magali ULiege; Coppée, Séverine et al

Book published by CRC Press (2017)

Hemicelluloses and Lignin in Biorefineries provides an understanding of lignocellulosic biomass, which is mainly composed of cellulose, hemicelluloses, and lignin. It promotes the valorization of these ... [more ▼]

Hemicelluloses and Lignin in Biorefineries provides an understanding of lignocellulosic biomass, which is mainly composed of cellulose, hemicelluloses, and lignin. It promotes the valorization of these molecules in the context of the bioeconomy and presents hemicelluloses and lignin, which are generated in lignocellulosic biorefineries, as the molecules of the future. The viability of these molecules lies in their renewability and potential. This book covers all aspects of hemicelluloses and lignin including structure, biosynthesis, extraction, biodegradation, and conversion. The book also looks ahead to the socioeconomic and environmental value of biobased industry and emphasizes an understanding of the potential of lignocellulosic biomass. [less ▲]

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See detailDevelopment of coated liposomes loaded with ghrelin for nose-to-brain delivery for the treatment of cachexia
Salade, Laurent; Wauthoz, Nathalie; Deleu, Magali ULiege et al

in International Journal of Nanomedicine (2017), 12

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See detailDifferential interaction of synthetic glycolipids with biomimetic plasma membrane lipids correlates with plant biological response
Nasir, Mehmet Nail ULiege; Lins, Laurence ULiege; Crowet, Jean-Marc ULiege et al

in Langmuir (2017)

Natural and synthetic amphiphilic molecules including lipopeptides, lipopolysaccharides and glycolipids are able to induce defense mechanisms in plants. In the present work, the perception of two ... [more ▼]

Natural and synthetic amphiphilic molecules including lipopeptides, lipopolysaccharides and glycolipids are able to induce defense mechanisms in plants. In the present work, the perception of two synthetic C14 rhamnolipids, namely Alk-RL and Ac-RL, differing only at the level of the lipid tail terminal group, have been investigated using biological and biophysical approaches. We showed that Alk-RL induces a stronger early signaling response in tobacco cell suspensions than does Ac-RL. The interactions of both synthetic RLs with simplified biomimetic membranes were further analyzed using experimental and in silico approaches. Our results indicate that the interactions of Alk-RL and Ac-RL with lipids were different in terms of insertion and molecular responses and were dependent on the lipid composition of model membranes. A more favorable insertion of Alk-RL than Ac-RL into lipid membranes is observed. Alk-RL forms more stable molecular assemblies than Ac-RL with phospholipids and sterols. At the molecular level, the presence of sterols tends to increase the RLs’ interaction with lipid bilayers with a fluidizing effect on the alkyl chains. Taken together, our findings suggest that the perception of these synthetic RLs at the membrane level could be related to a lipid-driven process depending on the organization of the membrane and the orientation of the RLs within the membrane and is correlated with the induction of early signaling responses in tobacco cells. [less ▲]

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See detailChanges in biophysical membrane properties induced by the Budesonide/ Hydroxy-β-cyclodextrin complex
dos Santos, Andreia; Bayiha, Jules; Dufour, Gilles et al

in BBA Biomembranes (2017)

Budesonide (BUD), a poorly soluble anti-inflammatory drug, is used to treat patients suffering from asthma and COPD (Chronic Obstructive Pulmonary Disease). Hydroxypropyl-β-cyclodextrin (HPβCD), a ... [more ▼]

Budesonide (BUD), a poorly soluble anti-inflammatory drug, is used to treat patients suffering from asthma and COPD (Chronic Obstructive Pulmonary Disease). Hydroxypropyl-β-cyclodextrin (HPβCD), a biocompatible cyclodextrin known to interact with cholesterol, is used as a drug-solubilizing agent in pharmaceutical formulations. Budesonide administered as an inclusion complex within HPβCD (BUD:HPβCD) required a quarter of the nominal dose of the suspension formulation and significantly reduced neutrophil induced inflammation in a COPD mouse model exceeding the effect of each molecule administered individually. This suggests the role of lipid domains enriched in cholesterol for inflammatory signaling activation. In this context, we investigated the effect of BUD:HPβCD on the biophysical properties of membrane lipids. On cellular models (A549, lung epithelial cells), BUD:HPβCD extracted cholesterol similarly to HPβCD. On large unilamellar vesicles (LUVs), by using the fluorescent probes diphenylhexatriene (DPH) and calcein, we demonstrated an increase in membrane fluidity and permeability induced by BUD:HPβCD in vesicles containing cholesterol. On giant unilamellar vesicles (GUVs) and lipid monolayers, BUD:HPβCD induced the disruption of cholesterol-enriched raft-like liquid ordered domains as well as changes in lipid packing and lipid desorption from the cholesterol monolayers, respectively. Except for membrane fluidity, all these effects were enhanced when HPβCD was complexed with budesonide as compared with HPβCD. Since cholesterol-enriched domains have been linked to membrane signaling including pathways involved in inflammation processes, we hypothesized the effects of BUD:HPβCD could be partly mediated by changes in the biophysical properties of cholesterol-enriched domains. [less ▲]

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See detailPlant Oxylipins: Structure-function Relationships
Genva, Manon ULiege; Andersson, Mats X.; Nasir, Mehmet Nail ULiege et al

Poster (2017)

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See detailMolecular dynamics study of micelle proeprties according to their size
Lebecque, Simon ULiege; Crowet, Jean-Marc ULiege; Nasir, Mehmet Nail ULiege et al

in Journal of Molecular Graphics and Modelling (2017), 72

Surfactants are molecules able to spontaneously self-assemble to form aggregates with well-defined properties, such as spherical micelles, planar bilayers, cylindrical micelles or vesicles. Micelles have ... [more ▼]

Surfactants are molecules able to spontaneously self-assemble to form aggregates with well-defined properties, such as spherical micelles, planar bilayers, cylindrical micelles or vesicles. Micelles have notably several applications in many domains, such as drug delivery or membrane protein solubilization. In this context, the study of micelle formation in relation with the structural and physico-chemical properties of surfactants is of great interest to better control their use in the different application fields. In this work, we use the MD approach developed by Yoshii et al. and extend it to surfactants with different structures. We aim to systematically investigate different micellar properties as a function of the aggregates size by a molecular dynamics approach, to get an insight into the micellar organization and to collect some relevant descriptors about micelle formation. For this, we perform short MD simulations of preformed micelles of various sizes and analyze three parameters for each micelle size, namely the eccentricity of the micelles, the hydrophobic/hydrophilic surface ratio and the hydrophobic tails hydration. If these parameters are known descriptors of micelles, they were not yet studied in this way by MD. We show that eccentricity, used as “validator” parameter, exhibits minimal values when the aggregate size is close to the experimental aggregation number for surfactants that are known to form spherical micelles. This hence indicates that our methodology gives consistent results. The evolution of the two descriptors follows another scheme, with a sharp increase and decrease, respectively, followed by a leveling-off. The aggregate sizes at which this stabilization starts to occur are close to the respective aggregation number of each surfactant. In our approach, we validate the use of these descriptors to follow micelle formation by MD, from “simple” surfactants to more complex structures, like lipopeptides. Our calculations also suggest that some peculiar behavior, like that of TPC, can be highlighted by our approach. In the context of peptidic surfactants, our methodology could further help to improve computer simulations combined to molecular thermodynamic models to predict micellar properties of those more complex amphiphilic molecules. [less ▲]

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