References of "Lins*, Laurence"
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See detailFunctional and structural characterisation of the Arabidopsis thaliana HMA4 protein
Lekeux, Gilles ULiege; Laurent, Clémentine; Xiao, Zhiguang et al

Poster (2017, July 24)

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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 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 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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See detailMembrane Interactions of Natural Cyclic Lipodepsipeptides of the Viscosin Group
Geudens, Niels; Nasir, Mehmet Nail ULiege; Crowet, Jean-Marc ULiege et al

in Biochimica et Biophysica Acta - Biomembranes (2017), 1859(3), 331-339

Many Pseudomonas spp. produce cyclic lipodepsipeptides (CLPs), which, besides their role in biological functions such as motility, biofilm formation and interspecies interactions, are antimicrobial. It ... [more ▼]

Many Pseudomonas spp. produce cyclic lipodepsipeptides (CLPs), which, besides their role in biological functions such as motility, biofilm formation and interspecies interactions, are antimicrobial. It has been established that interaction with the cellular membrane is central to the mode of action of CLPs. In this work, we focus on the CLPs of the so-called viscosin group, aiming to assess the impact of the main structural variations observed within this group on both the antimicrobial activity and the interaction with model membranes. The antimicrobial activity of viscosin, viscosinamide A, WLIP and pseudodesmin A were all tested on a broad panel of mainly Gram-positive bacteria. Their capacity to permeabilize or fuse PG/PE/cardiolipin model membrane vesicles is assessed using fluorescent probes. We find that the Glu2/Gln2 structural variation within the viscosin group is the main factor that influences both the membrane permeabilization properties and the minimum inhibitory concentration of bacterial growth, while the configuration of the Leu5 residue has no apparent effect. The CLPmembrane interactions were further evaluated using CD and FT-IR spectroscopy on model membranes consisting of PG/PE/cardiolipin or POPC with or without cholesterol. In contrast to previous studies, we observe no conformational change upon membrane insertion. The CLPs interact both with the polar heads and aliphatic tails of model membrane systems, altering bilayer fluidity, while cholesterol reduces CLP insertion depth [less ▲]

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See detailGROMPALA: a membrane-implicit modelling method to screen lipid-interacting molecules
Steinhauer, Sven; Crowet, Jean-Marc ULiege; Brasseur, Robert ULiege et al

in Mukhametov, Azat (Ed.) Software and techniques for Bio-molecular modeling (2016)

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See detailAnalysis of the interactions of fatty acyds hydroperoxides with biomimetic membranes by complementary biophysical approaches
Deboever, Estelle ULiege; Nasir, Mehmet Nail ULiege; Deleu, Magali ULiege et al

Poster (2016, November 16)

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 detailDevelopment of a new method for arabidopsides extraction and purification
Genva, Manon ULiege; Andersson, Mats X; Nasir, Mehmet Nail ULiege et al

Poster (2016, November 16)

In the present work, a new method for arabidopsides extraction and purification was developed.

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

Poster (2016, September)

In the present work, high quantities of arabidopsides were extracted and purified from Arabidopsis thaliana L.

Detailed reference viewed: 45 (13 ULiège)
See detailCaractérisation des mécanismes impliqués dans la perception de rhamnolipides naturels et synthétiques chez Arabidopsis thaliana
Luzuriaga Loaiza, Walter ULiege; Schellenberger, Romain; Obounou Akong, Firmin et al

Scientific conference (2016, July 05)

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See detailCover Letter of The journal of Biological Chemistry
Sautrey, Guillaume; El Khoury, M; Dos Giros, A et al

in The journal of Biological Chemistry (2016), 291(26),

Detailed reference viewed: 33 (1 ULiège)