References of "Lins, Laurence"
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See detailIs it possible to predict the odor of a molecule on the basis of its structure?
Genva, Manon ULiege; Kenne Kemene, Tierry ULiege; Deleu, Magali ULiege et al

in International Journal of Molecular Sciences (in press)

The olfactory sense is the dominant sensory perception for many animals. When Richard Axel and Linda Buck received in 2004 the Nobel Prize for discovering the G-protein coupled receptors role in olfactory ... [more ▼]

The olfactory sense is the dominant sensory perception for many animals. When Richard Axel and Linda Buck received in 2004 the Nobel Prize for discovering the G-protein coupled receptors role in olfactory cells, it highlighted the importance of olfaction to scientific community. Several theories tried to explain how cells are able to distinguish such a wide variety of odorant molecules in a complex context in which enantiomers can result in completely different perceptions and structurally different molecules in the same one. Moreover, sex, age, cultural origin and individual differences contribute to odor perception variations that complicate the picture. Recent advances in olfaction theory will be presented and future trends in human olfaction like structure-based odor prediction or artificial sniffing will be discussed at the frontiers of chemistry, physiology, neurobiology and machine learning. [less ▲]

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See detailMultiple C2 domains and Transmembrane region Proteins (MCTPs) tether membranes at plasmodesmata
Brault, Marie; Petit, Jules ULiege; Immel, Françoise et al

in EMBO Reports (in press)

In eukaryotes, membrane contact sites (MCS) allow direct communication between organelles. Plants have evolved a unique type of MCS, inside intercellular pores, the plasmodesmata, where endoplasmic ... [more ▼]

In eukaryotes, membrane contact sites (MCS) allow direct communication between organelles. Plants have evolved a unique type of MCS, inside intercellular pores, the plasmodesmata, where endoplasmic reticulum (ER) - plasma membrane (PM) contacts coincide with regulation of cell-to-cell signalling. The molecular mechanism and function of membrane tethering within plasmodesmata remains unknown. Here we show that the Multiple C2 domains and Transmembrane region Protein (MCTP) family, key regulators of cell-to-cell signalling in plants, act as ER-PM tethers specifically at plasmodesmata. We report that MCTPs are core plasmodesmata proteins that insert into the ER via their transmembrane region whilst their C2 domains dock to the PM through interaction with anionic phospholipids. A Atmctp3/Atmctp4 loss-of-function mutant induces plant developmental defects while MCTP4 expression in a yeast Δtether mutant partially restores ER-PM tethering. Our data suggest that MCTPs are unique membrane tethers controlling both ER-PM contacts and cell-to-cell signalling. [less ▲]

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See detailSearching for interactions at the membrane interface that confer antagonistic activities on floral regulators FT and TFL1
Pottier, Mathieu ULiege; Orman-Ligeza, Beata; Redouté, Gaëlle et al

Poster (2019, July)

In plants, the switch from leaf- to flower-producing meristems is controlled by the FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1) proteins. FT is a major component of the so-called "florigen", a ... [more ▼]

In plants, the switch from leaf- to flower-producing meristems is controlled by the FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1) proteins. FT is a major component of the so-called "florigen", a systemic signal that moves from leaves to shoot meristems and triggers the floral transition. By contrast, TFL1 is expressed in the shoot meristems and represses flowering, antagonising FT. Despite their opposite functions, FT and TFL1 are both members of the same family, showing homology to PHOSPHATIDYLETHANOLAMINE BINDING PROTEINs (PEBPs). They are unable to bind phosphatidylethanolamines though, but bind phosphatidylcholines that are major phospholipids of plant membranes and whose concentration impacts flowering time (Nakamura et al., 2014). The mechanisms by which FT and TFL1 regulate floral transition have been focused on their ability to complex with the transcription factor FD, which itself regulates floral identity genes. However, the loss of FD function does not abolish flowering and hence other interactors remain to be identified. We are therefore investigating in further detail the ability of Arabidopsis FT and TFL1 proteins to interact with membrane lipids and proteins. Langmuir method and molecular dynamics are currently being undertaken to characterize FT and TFL1 interactions with different phospholipids and to simulate their behaviors in contact with membranes, respectively. In parallel, FT and TFL1 protein interactomes are being investigated. We are performing in vitro pulldown assays using His-FT and His-TFL1 as baits and solubilized membranes proteins from cauliflower meristem as preys, taking advantage of the conservation of flowering genes among Brassicaceae. In parallel, complementation of Arabidopsis ft and tfl1 mutants with FT-GS and TFL1-GS constructs allowed us to perform in vivo co-purification analyses. This work will provide us with a better understanding of FT and TFL1 actions and highlight missing checkpoints of the floral transition. [less ▲]

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See detailStress-related accumulation of arabidopsides: impact on chloroplast membranes
Genva, Manon ULiege; Deleu, Magali ULiege; Andersson, M.X. et al

Poster (2019, April)

Oxylipins are crucial agents in plant defense mechanisms. While free oxylipins are well studied, roles of esterified oxylipins remain unclear. Esterified oxylipins are structurally diverse metabolites ... [more ▼]

Oxylipins are crucial agents in plant defense mechanisms. While free oxylipins are well studied, roles of esterified oxylipins remain unclear. Esterified oxylipins are structurally diverse metabolites that were found in diverse plant species, suggesting that those may be more ubiquitous that currently thought. Among those, galactolipids containing (dn)OPDA were discovered, firstly in A. thaliana, but also in other plants. Those molecules, named arabidopsides, are highly induced under stress conditions, as it accumulates up to 8 percent of plant lipids, but their precise contributions in plant defense mechanisms are still unknown. Arabidopsides are directly formed in plant chloroplast membranes from galactolipids. Accumulation of arabidopsides in such high quantity in chloroplast membranes may modify their properties (e.g. photosynthetic activity). This study aims to understand the impact of arabidopside presence in chloroplast membranes on their properties using biomimetic plant membranes via complementary in silico and in vitro approaches. Interfacial properties of arabidopsides and non-oxidized galactolipids were studied using Langmuir film balance. Results showed that arabidopsides possess different interfacial properties compared to non-oxidized chloroplast lipids. Arabidopsides ability to permeabilize chloroplast membranes was also studied in vitro. Arabidopsides A and B are able to permeabilize chloroplast membranes while arabidopside D is not. In conclusion, arabidopside production by plants under stress conditions may modify chloroplast membrane properties such as its permeability. As chloroplast membrane lipid composition is essential to its photosynthetic ability, such changes may also affect its function. [less ▲]

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See detailInteractions between natural herbicides and lipid bilayers mimicking the plant plasma membrane
Lebecque, Simon ULiege; Lins, Laurence ULiege; Dayan, Franck E. et al

in Frontiers in Plant Science (2019), 10

Natural phytotoxic compounds could become an alternative to traditional herbicides in the framework of sustainable agriculture. Nonanoic acid, sarmentine and sorgoleone are such molecules extracted from ... [more ▼]

Natural phytotoxic compounds could become an alternative to traditional herbicides in the framework of sustainable agriculture. Nonanoic acid, sarmentine and sorgoleone are such molecules extracted from plants and able to inhibit the growth of various plant species. However, their mode of action is not fully understood and despite clues indicating that they could affect the plant plasma membrane, molecular details of such phenomenon are lacking. In this paper, we investigate the interactions between those natural herbicides and artificial bilayers mimicking the plant plasma membrane. First, their ability to affect lipid order and fluidity is evaluated by means of fluorescence measurements. It appears that sorgoleone has a clear ordering effect on lipid bilayers, while nonanoic acid and sarmentine induce no or little change to these parameters. Then, a thermodynamic characterization of interactions of each compound with lipid vesicles is obtained with isothermal titration calorimetry, and their respective affinity for bilayers is found to be ranked as follows: sorgoleone > sarmentine > nonanoic acid. Finally, molecular dynamics simulations give molecular details about the location of each compound within a lipid bilayer and confirm the rigidifying effect of sorgoleone. Data also suggest that mismatch in alkyl chain length between nonanoic acid or sarmentine and lipid hydrophobic tails could be responsible for bilayer destabilization. Results are discussed regarding their implications for the phytotoxicity of these compounds. [less ▲]

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See detailArabidopside interactions with plant membranes
Genva, Manon ULiege; Deleu, Magali ULiege; Andersson, Mats X. et al

Poster (2019, February 04)

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See detailLipids or Proteins: Who is leading the dance at Membrane Contact Sites?
Petit, Jules ULiege; Immel, Françoise; Lins, Laurence ULiege et al

in Frontiers in Plant Science (2019)

Understanding the mode of action of membrane contact sites (MCSs) across eukaryotic organisms at the near-atomic level to infer function at the cellular and tissue levels is a challenge scientists are ... [more ▼]

Understanding the mode of action of membrane contact sites (MCSs) across eukaryotic organisms at the near-atomic level to infer function at the cellular and tissue levels is a challenge scientists are currently facing. These peculiar systems dedicated to inter-organellar communication are perfect examples of cellular processes where the interplay between lipids and proteins is critical. In this mini review, we underline the link between membrane lipid environment, the recruitment of proteins at specialized membrane domains and the function of membrane contact sites. More precisely, we want to give insights on the crucial role of lipids in defining the specificity of plant endoplasmic reticulum (ER)-plasma membrane (PM) MCSs and we further propose approaches to study them at multiple scales. Our goal is not so much to go into detailed description of MCSs, as there are numerous focused reviews on the subject, but rather try to pinpoint the critical elements defining those structures and give an original point of view by considering the subject from a near-atomic angle with a focus on lipids. We review current knowledge as to how lipids can define MCS territories, play a role in the recruitment and function of the MCS-associated proteins and in turn, how the lipid environment can be modified by proteins. [less ▲]

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See detailLinoleic and linolenic acid hydroperoxides interact differentially with biomimetic plant membranes in a lipid specific manner
Deleu, Magali ULiege; Deboever, Estelle ULiege; Nasir, Mehmet Nail et al

in Colloids and Surfaces B: Biointerfaces (2019), 175

Linoleic and linolenic acid hydroperoxides (HPOs) constitute key intermediate oxylipins playing an important role as signaling molecules during plant defense processes in response to biotic or abiotic ... [more ▼]

Linoleic and linolenic acid hydroperoxides (HPOs) constitute key intermediate oxylipins playing an important role as signaling molecules during plant defense processes in response to biotic or abiotic stress. They have also been demonstrated in vitro as antimicrobial agents against plant fungi and bacteria. To reach the phytopathogens in vivo, the HPOs biosynthesized in the plant cells must cross the plant plasma membrane (PPM) where they can also interact with plasma membrane lipids and have an effect on their organization.In the present study, we have investigated the interaction properties of HPOs with PPM at a molecular level using biophysical tools combining in vitro and in silico approaches and using plant biomimetic lipid systems. Our results have shown that HPOs are able to interact with PPM lipids and perturb their lateral organization. Glucosylceramide (GluCer) is a privileged partner, sitosterol lessens their binding and the presence of both GluCer and sitosterol further reduces their interaction. Hydrophobic effect and polar interactions are involved in the binding. The chemical structure of HPOs influences their affinity for PPM lipids. The presence of three double bonds in the HPO molecule gives rise to a higher affinity comparatively to two double bonds, which can be explained by their differential interaction with the lipid polar headgroups. [less ▲]

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See detailHomology modeling and in vivo functional characterization of the zinc permeation pathway in a heavy metal P-type ATPase
Lekeux, Gilles ULiege; Crowet, Jean-Marc; Nouet, Cécile ULiege et al

in Journal of Experimental Botany (2019), 70

The P1B ATPase Heavy Metal ATPase 4 (HMA4) is responsible for zinc and cadmium translocation from roots to shoots in the plant Arabidopsis thaliana. It couples ATP hydrolysis to cytosolic domain movements ... [more ▼]

The P1B ATPase Heavy Metal ATPase 4 (HMA4) is responsible for zinc and cadmium translocation from roots to shoots in the plant Arabidopsis thaliana. It couples ATP hydrolysis to cytosolic domain movements enabling metal transport across the membrane. Thanks to high conservation level within the P-type ATPase family, the role of the HMA4 cytoplasmic catalytic domains can be inferred from well characterized pumps. In contrast, the function of its terminal cytosolic extensions as well as the metal permeation mechanism through the membrane remains elusive. Here, homology modeling of the HMA4 transmembrane region was conducted based on the crystal structure of a ZntA bacterial homolog. The analysis highlighted amino acids forming a metal permeation pathway, whose importance was subsequently investigated functionally through mutagenesis and complementation experiments in plants. Although the zinc pathway displayed overall conservation among the two proteins, significant differences were observed, especially in the entrance area with altered electronegativity and the presence of a salt bridge/H-bond network. The analysis also newly identified amino acids whose mutation results in total or partial loss of the protein function. In addition, comparison of zinc and cadmium accumulation in shoots of A. thaliana complemented lines revealed a number of HMA4 mutants exhibiting different abilities in zinc and cadmium translocation. These observations could be instrumental to design low cadmium accumulating crops, hence decreasing human cadmium exposure . [less ▲]

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See detailNew insights into the biosynthesis of esterified oxylipins and their involvement in plant defense and developmental mechanisms
Genva, Manon ULiege; Obounou Akong, Firmin ULiege; Andersson, Mats X. et al

in Phytochemistry Reviews (2018)

Plant oxylipins produced following oxidation of unsaturated fatty acids are structurally diverse metabolites that play crucial developmental and defensive roles. Whereas free oxylipins are well studied ... [more ▼]

Plant oxylipins produced following oxidation of unsaturated fatty acids are structurally diverse metabolites that play crucial developmental and defensive roles. Whereas free oxylipins are well studied, oxylipins esterified in complex lipids such as galacto- and phospholipids are thought to be rare and have unclear roles. In the last few years, new analytical methods have been developed, leading to the discovery of many esterified oxylipins in a variety of plant species. This suggests that these molecules may be ubiquitous plant metabolites. While their precise functions are unclear, esterified oxylipins seem to play important roles in plant development and defense. This review focuses on new insights regarding diversity, biosynthesis and function of those interesting and understudied molecules. [less ▲]

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See detailOxylipins are involved in plant protections processes and are potential biocontrol agents
Deboever, Estelle ULiege; Genva, Manon ULiege; Deleu, Magali ULiege et al

Conference (2018, September 27)

Nowadays, biopesticides have emerged as a main alternative to conventional agriculture. In this context, plant oxylipins, a vast and diverse family of secondary metabolites originated from polyunsaturated ... [more ▼]

Nowadays, biopesticides have emerged as a main alternative to conventional agriculture. In this context, plant oxylipins, a vast and diverse family of secondary metabolites originated from polyunsaturated fatty acids (PUFAs), appear to be crucial agents in plant defence mechanisms. Among plant oxylipins, the 13-hydroperoxy oxylipins (13-HPO) constitute key intermediate oxylipins (KIOs) as they can be converted into jasmonic acid, OPDA, dn-OPDA or traumatic acid, well-characterized components involved in plant resistance mechanisms [1][2]. Their presumed functions include direct antimicrobial effect, stimulation of plant defence gene expression, and/or regulation of plant cell death [3]. Otherwise, OPDA and dn-OPDA were also found esterified in more complex structures such as galactolipids. Those compounds are called arabidopsides. However, the precise contribution of each of those molecules in plant defence remains unknown. The first part of this study aims to understand the oxylipins action mechanisms and especially their membrane activities. As arabidopsides are produced under stress and localized at the chloroplast membranes, their interactions with those were studied using biomimetic membranes via a complementary in silico informatics and in vitro biophysical approaches. On the other hand, as KIOs are found in the literature to be potential biocontrol agents, there effect on different pathogens of agronomic interest were studied in vitro, by the same approach. As far as arabidopsides are concerned, results show that they possess different interfacial properties compared to major chloroplast lipids, which they are produced from. Arabidopsides modify the fluidity and permeabilize chloroplast membranes. As chloroplast membrane lipid composition is essential to its photosynthetic ability, such changes in its composition under stress will affect its function. Concerning KIOs, they seem to interact with pathogens plasma membranes. Indeed, in vitro assays show that KIOs can hinder growth of some plant microbial pathogens, with differences between strains and KIOs forms. [less ▲]

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See detailHow could the herbicidal effects of selected essential oil compounds be related to their membrane activity ?
Lins, Laurence ULiege; Bettaieb, Ines; Dal Maso, Simon ULiege et al

Poster (2018, September 25)

The European legislation on plant protection products (PPP) is about to undergo important changes in the coming years. The chemical PPP destined to be removed from the European market are responsible for ... [more ▼]

The European legislation on plant protection products (PPP) is about to undergo important changes in the coming years. The chemical PPP destined to be removed from the European market are responsible for the appearance of resistance phenomena to plants pests. It is therefore necessary to explore new alternatives, one of them being the search for natural herbicides. Essential oils (EO) could provide a welcome alternative due to their proven activity as PPP. Even if these compounds seem to have a bright future as PPP, their activity is mainly approached through empirical observations. EO are also a complex mix of of different molecules that could act individually or in synergy. Particularly, very little is known when it comes to molecular mechanisms of action and the relations between structure and activity of the active compounds. This study aims to investigate the structure/activity relationships of some EO molecules, among which cinnamaldehyde (CIN) from cinnamon and citronellal and citronellol from lemongrass. Due to their lipophilic properties, EO tend to interact with one or more of the layers found in the outer plant tissues, among which the cell membranes. For cinnalmaldehyde (and other EO compounds), it has been shown that they are able to interact with bacterial phospholipids and induce change in lipid organization (fluidity, packing,..) on model lipid monolayers (Nowotarska et al, 2014). Citronnellol was notably shown to displace cholesterol from its phospholipid complexes (Lange, Y et al, 2009). However, nothing is known about any interaction with lipids specific to plant plasma membrane (PPM). In this study, we analyzed the effects of the above three EO compounds on model PPM by complementary in vitro and in silico biophysical approaches. We showed that the three compounds have differential effects on plant lipids and different herbicidal properties on plantae. While part of the herbicidal activity could be related to membrane perturbation, some clues remain to be elucidated. Future studies at a molecular point of view would help to better decipher the herbicidal action involving the membrane, other outer plant tissues such as the cuticule and/or and a potential effect on EO compounds on proteins or genomic DNA, as it was shown for CIN on E. Coli (He, TF et al, 2018). [less ▲]

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See detailThe molecular mechanisms of membrane tethering at plasmodesmata intercellular junctions
Petit, Jules ULiege; Brault, Marie; Immel, Françoise et al

Poster (2018, September)

Intercellular communication is critical for multicellularity. It coordinates the activities within individual cells to support the function of an organism as a whole. Plants have developed remarkable ... [more ▼]

Intercellular communication is critical for multicellularity. It coordinates the activities within individual cells to support the function of an organism as a whole. Plants have developed remarkable cellular machines -the Plasmodesmata (PD) pores- which interconnect every single cell within the plant body, establishing direct membrane and cytoplasmic continuity, a situation unique to plants. PD are indispensable for plant life hence human health. They control the flux of molecules between cells and are decisive for development, environmental adaptation and defence signalling. A striking feature of PD organisation, setting them apart from animal cell junctions, is a strand of endoplasmic reticulum (ER) running through the pore, tethered extremely tight (~10nm) to the plasma membrane (PM) by unidentified “spokes”. To date the function of ER-PM contacts at PD remains a complete enigma. We don’t know the molecular mechanisms controlling this highly specialized membrane junctions. Our work focuses on investigating the structure/function of the C2 domains of the Multiple C2 domains and Transmembrane region Proteins (MCTPs) family, which are candidate ER-PM tethers. Sequence analysis of the MCTPs was performed to delimit the C2 domains and molecular modelling was used to build accurate 3D models that were used for molecular dynamic simulations. Our results suggest the ability of C2 domains to dock onto biomimetic lipid bilayers, in an anionic lipid-dependent manner, as a result of electrostatic interactions between basic amino residues and lipid polar heads. [less ▲]

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See detailSynthetic Rhamnolipid Bolaforms trigger an innate immune response in Arabidopsis thaliana
Luzuriaga Loaiza, Walter ULiege; Schellenberger, Romain; De-Gaetano, Yannick et al

in Scientific Reports (2018), 8

Stimulation of plant innate immunity by natural and synthetic elicitors is a promising alternative to conventional pesticides for a more sustainable agriculture. Sugar-based bolaamphiphiles are known for ... [more ▼]

Stimulation of plant innate immunity by natural and synthetic elicitors is a promising alternative to conventional pesticides for a more sustainable agriculture. Sugar-based bolaamphiphiles are known for their biocompatibility, biodegradability and low toxicity. In this work, we show that Synthetic Rhamnolipid Bolaforms (SRBs) that have been synthesized by green chemistry trigger Arabidopsis innate immunity. Using structure-function analysis, we demonstrate that SRBs, depending on the acyl chain length, differentially activate early and late immunity-related plant defense responses and provide local increase in resistance to plant pathogenic bacteria. Our biophysical data suggest that SRBs can interact with plant biomimetic plasma membrane and open the possibility of a lipid driven process for plant-triggered immunity by SRBs. [less ▲]

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See detailHow different serols contribute to cytotoxic action of sea cucumber saponins
Claereboudt, Emily ULiege; Eeckhaut, Igor; Deleu, Magali ULiege et al

Poster (2018, May 24)

Saponins form a diverse class of secondary metabolites found in both plants and some marine invertebrates. Holothuroids, or sea cucumbers, produce these molecules as a chemical defense against predators ... [more ▼]

Saponins form a diverse class of secondary metabolites found in both plants and some marine invertebrates. Holothuroids, or sea cucumbers, produce these molecules as a chemical defense against predators and parasites, but interestingly, tolerate the cytotoxic nature of these chemicals. This tolerance is poorly understood. The aim of this study was therefore to elucidate the mechanisms behind the tolerance of holothuroid cells to the cytotoxic saponins (e.g. Frondoside A) they produce. This investigation was conducted using a suite of complementary biophysical tools, firstly using in vitro techniques such as Isothermal Titration Calorimetry (ITC) and calcein leakage experiments, for measuring interactions between lipid models of various compositions and the saponin Frondoside A, then using in silico approaches such as docking methods and insertion into implicit lipid bilayers, to provide a molecular point of view on our observations. Interactions between Frondoside A and cholesterol were more favorable than those with the holothuroid Δ7 and Δ9(11) sterols. Liposomes containing cholesterol resulted in exothermic interactions with the holothuroid saponin Frondoside A whereas liposomes containing the Δ7 sterol resulted in endothermic interactions. Lipid phase simulations using settings previously developed for plant saponins revealed that the holothuroid saponin Frondoside A has an agglomerating effect on cholesterol domains, similar to that previously observed for the plant saponin α-Hederin. However, when interacting with the Δ7 sterols, the sterol domains were fragmented into small clusters. A significantly lower leakage was observed with liposomes containing the Δ7 holothuroid sterol than that with liposomes containing cholesterol. Our results suggest that the structural peculiarities of holothuroid sterols provide the organisms with a mechanism to mitigate the sterol-agglomerating effect of saponins on the cell membranes, and therefore to protect sea cucumber cells from the cytotoxicity of the saponins they produce. [less ▲]

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See detailInteractions of allelochemicals with plant plasma membrane: a case study with alkaloids from barley
Lebecque, Simon ULiege; Crowet, Jean-Marc; du Jardin, Patrick ULiege et al

Poster (2018, April)

Allelopathy is defined as “any direct or indirect harmful effect by one plant on another through production of chemical compounds that escape into the environment” (Rice, 1974).This phenomenon is seen as ... [more ▼]

Allelopathy is defined as “any direct or indirect harmful effect by one plant on another through production of chemical compounds that escape into the environment” (Rice, 1974).This phenomenon is seen as a potential tool for weeds management within the framework of sustainable agriculture. While many studies investigated the mode of action of various allelochemicals (molecules emitted by allelopathic plants), little attention was given to their initial contact with the plant plasma membrane. In our work, this key step is explored for two alkaloids, gramine and hordenine, that are allelochemicals produced by barley. [less ▲]

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See detailHow different sterols contribute to saponin tolerant plasma membranes in sea cucumbers
Claereboudt, Emily ULiege; Deleu, Magali ULiege; Lins, Laurence ULiege et al

Scientific conference (2018, March 07)

ABSTRACT. Sea cucumbers produce saponins as a chemical defense mechanism, however their cells can tolerate the cytotoxic nature of these chemicals. To elucidate the molecular mechanisms behind this ... [more ▼]

ABSTRACT. Sea cucumbers produce saponins as a chemical defense mechanism, however their cells can tolerate the cytotoxic nature of these chemicals. To elucidate the molecular mechanisms behind this tolerance a suite of complementary biophysical tools was used, firstly using liposomes for in vitro techniques then using in silico approaches for a molecular-level insight. The holothuroid saponin Frondoside A, caused significantly less permeabilization in liposomes containing a Δ7 holothuroid sterol than those containing cholesterol and resulted in endothermic interactions versus exothermic interactions with cholesterol containing liposomes. Lipid phases simulations revealed that Frondoside A has an agglomerating effect on cholesterol domains, however, induced small irregular Δ7 sterol clusters. Our results suggest that the structural peculiarities of holothuroid sterols provide sea cucumbers with a mechanism to mitigate the sterol-agglomerating effect of saponins, and therefore to protect their cells from the cytotoxicity of the saponins they produce. [less ▲]

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See detailUse of molecular dynamics simulations to study the interactions between barley allelochemicals and plant plasma membrane
Lebecque, Simon ULiege; Crowet, Jean-Marc; du Jardin, Patrick ULiege et al

Poster (2018, March)

Gramine and hordenine, two alkaloids produced by barley, were shown to inhibit the growth of a common weed (Matricaria recutita L.). This feature could be useful in order to reach a more sustainable weeds ... [more ▼]

Gramine and hordenine, two alkaloids produced by barley, were shown to inhibit the growth of a common weed (Matricaria recutita L.). This feature could be useful in order to reach a more sustainable weeds management. In vitro experiments have proven that both molecules do interact with lipid bilayers (made of a phosphatidylglycerol (PG) lipid) mimicking plant plasma membranes and are able to modify some of their properties. Moreover, gramine was shown to be more effective than hordenine in both inhibiting weeds growth and altering lipid bilayers properties, suggesting that interactions with membranes could be linked to their mode of action. Molecular dynamics (MD) simulations are carried out in order to get an insight into the molecular mechanisms that underlie these interactions with model membranes and to discriminate between gramine behavior and hordenine behavior. [less ▲]

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