References of "Thonart, Philippe"
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See detailLack of isocitrate lyase in Chlamydomonas leads to changes in carbon metabolism and in the response to oxidative stress under mixotrophic growth.
Plancke, Charlotte; Vigeolas, Hélène ULg; Hohner, Ricarda et al

in The Plant journal : for cell and molecular biology (2014), 77(3), 404-417

Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the ... [more ▼]

Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the tricarboxylic acid (TCA) cycle in which CO2 is evolved. In this paper, a null icl mutant of the green microalga Chlamydomonas reinhardtii is described. Our data show that isocitrate lyase is required for growth in darkness on acetate (heterotrophic conditions), as well as for efficient growth in the light when acetate is supplied (mixotrophic conditions). Under these latter conditions, reduced acetate assimilation and concomitant reduced respiration occur, and biomass composition analysis reveals an increase in total fatty acid content, including neutral lipids and free fatty acids. Quantitative proteomic analysis by 14 N/15 N labelling was performed, and more than 1600 proteins were identified. These analyses reveal a strong decrease in the amounts of enzymes of the glyoxylate cycle and gluconeogenesis in parallel with a shift of the TCA cycle towards amino acid synthesis, accompanied by an increase in free amino acids. The decrease of the glyoxylate cycle and gluconeogenesis, as well as the decrease in enzymes involved in beta-oxidation of fatty acids in the icl mutant are probably major factors that contribute to remodelling of lipids in the icl mutant. These modifications are probably responsible for the elevation of the response to oxidative stress, with significantly augmented levels and activities of superoxide dismutase and ascorbate peroxidase, and increased resistance to paraquat. [less ▲]

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See detailThe facultative bacterial symbiont Serratia symbiotica in Acyrtosiphon pisum confer resistance to Aphidius ervi
Attia, Sabrine; Foray, Vincent; Louâpres, Philippe et al

Poster (2014)

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See detailValorisation et propriétés des substances humiques des lixiviats de décharge
Tahiri, Abdelghani ULg; Destain, Jacqueline ULg; Thonart, Philippe ULg et al

Conference (2013, December 18)

Des expérimentations ont été menées dans notre laboratoire en utilisant des substances humiques (SH) extraites des lixiviats de cEntre d’Enfouissemnt Techique et des une formulation stable de SH « ... [more ▼]

Des expérimentations ont été menées dans notre laboratoire en utilisant des substances humiques (SH) extraites des lixiviats de cEntre d’Enfouissemnt Techique et des une formulation stable de SH « Humifirst » (12%d’acides humiques et 3% d’acides fulviques) de la compagnie TRADECORP s.a. (Espagne) commercialisée sous l’appelation Humifirst en vue d’en étudier leurs effets sur le développement du système racinaire de vitro-plants de bouleau et d’aulne. Les résultats montrent qu‘un traitement à faible concentration (10ppm) pendant la phase d’élongation des racines affecte la formation des racines latérales formée en présence de SH de lixiviat avec une intensité variable selon l’espèce testée. [less ▲]

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See detailEnhancement of thermophillic anaerobic digestion of methane by metal nanoparticles encapsulated in porous silica
Al-Ahmad, Alaa Eddin ULg; Hiligsmann, Serge ULg; Lambert, Stéphanie ULg et al

Poster (2013, December 05)

Increased demand and progressive depletion of fossil fuels, and worldwide concerns about greenhouse gas emissions have resulted in the development of promising technologies for renewable energy production ... [more ▼]

Increased demand and progressive depletion of fossil fuels, and worldwide concerns about greenhouse gas emissions have resulted in the development of promising technologies for renewable energy production. Therefore, potential alternatives for energy generation are intensively studied. One option is the use of biomass feedstock for the production of biogas through anaerobic digestion. This process is a biochemical technological process for the treatment of a wide range of feedstocks (e.g. organic fraction of municipal waste, animal manure and slurry, agricultural crops, etc.) to produce methane-rich biogas which can be used in replacement of fossil fuels in both heat and power generation and as a vehicle fuel. However, there are critical issues, which need to be addressed to make the production of bio-methane techno-economically viable and ecologically acceptable. One of the most important issues is the effect of trace metals addition on anaerobic digestion. These metals can be stimulatory, inhibitory, or even toxic for biochemical reactions, depending on their concentrations. As reported in literature, Ni, Co and Fe are all involved in the methane production biochemical process and serve as cofactors in enzymes which are involved in the biochemistry of methane formation (Zandvoort et al., 2006). Recently, enormous interest has been focused on biological applications of metal nanoparticles NPs due to their small size, high specified surface and their great potential in application to many science fields. The most studied process concerns zero valent palladium and iron NPs improving anaerobic biodegradation of chlorinated hydrocarbons (Windt et al., 2005). Moreover, investigation carried out in our lab showed that iron NPs encapsulated in silicate matrix may enhance hydrogen production by Clostridium butyricum (Beckers et al., 2013). Nevertheless the influences of metal NPs on methane producing anaerobic digestion have seldom been investigated. The present work investigates the enhancement effect of seven different metal NPs on methane production during the thermophilic anaerobic digestion. NPs of Cu, Pd, Pt, Ni, Co, Ag and Fe encapsulated in porous silica (SiO2) to prevent their coagulation and agglomeration, were added at concentration of 10-5mol/L in batch test (125ml serum bottles containing 70mL culture medium with 5g/L acetate monohydrate as the sole carbon substrate. Nickel, cobalt and iron NPs improved methane production from acetate. To confirm the previous results, the NPs were tested at different concentrations (10-4, 10-5, and 10-6 mol/L) with starch and glucose substrates. The results show that the impact increases with the increase of NPs concentrations up to 10-4 mol/L. The modified Gompertz equation was applied to describe the effect of NPs on anaerobic digestion. According to this model, the kinetic of methane production was particularly affected by nanoparticles addition. The values of the maximum methane production rate MPR (ml/day) was significantly higher 72.5% with nickel NPs at a concentration of 10-4 mol/L than the control without NPs. [less ▲]

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See detailTandem MS of -new- antibiotics from Bacillus guided by MALDI Mass Spectrometry Imaging
Debois, Delphine ULg; Jourdan, Emmanuel; Cawoy, Hélène ULg et al

Conference (2013, December 05)

Generally, an antibiotic is thought to have a role in antagonism simply because the producing strain is known to exhibit a potential for pathogen growth inhibition. Some genetic approaches such as PCR ... [more ▼]

Generally, an antibiotic is thought to have a role in antagonism simply because the producing strain is known to exhibit a potential for pathogen growth inhibition. Some genetic approaches such as PCR using specific primers or genome mining using known sequence data of close relatives are also used. Nevertheless, none of these methods allows stating for a link between a specific compound and the observed antagonism. Yet MALDI Mass Spectrometry Imaging (MSI) is a powerful tool to decipher the chemical messengers exchanged by two protagonists [1,2,3;]. Tandem mass spectrometry (MS/MS) may be also used, either on extracts [2,3] or directly on the microbial colonies [4]. The presentation will thus be focused on two examples of application of MALDI MSI combined to in situ tandem mass spectrometry. The first presented case will be the antagonism between soilborne strain Paenibacillus polymyxa Pp56 and the fungal phytopathogen Fusarium oxysporum. Using MALDI MSI, we were able to precisely localize each detected antibiotic, allowing discriminating which LI-F lipopeptides (fusaricidin) were really active against the pathogen progression. Besides, the use of in situ MS/MS allowed us to sequence the peptide moiety of several LI-F lipopeptides, showing that some of them are actually a mixture of several forms. The second example concerns the metabolites that are released by Bacillus amyloliquefaciens S499 cells following their inoculation on 7 days old tomato roots. We developed specific bioassays for time-course monitoring by MALDI MSI. First analyses revealed an efficient secretion of surfactin by Bacillus cells after 3 days when colonization as biofilm-structured populations is well established. Even if the composition of antibiotic mixture does not greatly evolve over time, after long incubation periods (32 or 35 days post inoculation), new series of compounds are detected in the tomato root -surrounding medium. Structural analysis based on exact mass measurements and MS/MS experiments, performed directly on the semi-solid agar medium, allowed us to identify these compounds as new variants of surfactins. [1] Barger, S., et al., Anton Leeuw Int J G, 2012, 102, 435-445. [2] Hoefler, B. C., et al,. Natl Acad Sci USA, 2012, 109, 13082-13087. [3] Moree, W. J., et al., Natl Acad Sci USA, 2012, 109, 13811-13816. [4] Debois, D., et al., J Am Soc Mass Spectrom. 2013, 24, 1202-1213 [less ▲]

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See detailTechnologie de production de masse d’insectes - INSECTECH
Richard, Gaetan ULg; Hance, Thierry; Fauconnier, Marie-Laure ULg et al

Report (2013)

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See detailShort communication - Isolation of amylolytic, xylanolytic, and cellulolytic microorganisms extracted from the gut of the termite Reticulitermes santonensis by means of a micro-aerobic atmosphere
Tarayre, Cédric ULg; Brognaux, Alison ULg; Bauwens, Julien ULg et al

in World Journal of Microbiology & Biotechnology (2013)

The aim of this work was to isolate enzyme-producing microorganisms from the tract of the termite Reticulitermes santonensis. The microorganisms were extracted from the guts and anaerobic (CO2 or CO2/H2 ... [more ▼]

The aim of this work was to isolate enzyme-producing microorganisms from the tract of the termite Reticulitermes santonensis. The microorganisms were extracted from the guts and anaerobic (CO2 or CO2/H2) and micro-aerobic atmospheres were used to stimulate growth. Three different strategies were tried out. First, the sample was spread on Petri dishes containing solid media with carboxymethylcellulose, microcrystalline cellulose or cellobiose. This technique allowed us to isolate two bacteria: Streptomyces sp. strain ABGxAviA1 and Pseudomonas sp. strain ABGxCellA. The second strategy consisted in inoculating a specific liquid medium containing carboxymethylcellulose, microcrystalline cellulose, or cellobiose. The samples were then spread on Petri dishes with the same specific medium containing carboxymethylcellulose, microcrystalline cellulose, or cellobiose. This led to the isolation of the mold Aspergillus sp. strain ABGxAviA2. Finally, the third strategy consisted in heating the first culture and spreading samples on agar plates containing rich medium. This led to the isolation of the bacterium Bacills subtilis strain ABGx. All those steps were achieved in controlled atmospheres. The four enzyme-producing strains which were isolated were obtained by using a micro-aerobic atmosphere. Later, enzymatic assays were performed on the four strains. Streptomyces sp. strain ABGxAviA1 was found to produce only amylase, while Pseudomonas sp. strain ABGxCellA was found to produce β-glucosidase as well. Aspergillus sp. strain ABGxAviA2 showed β-glucosidase, amylase, cellulase, and xylanase activities. Finally, Bacillus subtilis strain ABGx produced xylanase and amylase. [less ▲]

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See detailPeptidomic comparison and characterization of the major components of the venom of the giant ant Dinoponera quadriceps collected in four different areas of Brazil.
Cologna, Camila Takeno; Cardoso, Jaqueline Dos Santos; Jourdan, Emmanuel et al

in Journal of Proteomics (2013), 94

Despite the noxious effects inflicted by Dinoponera ant's envenomation, the information about the biological properties and composition of their venom is still very limited. Ants from the genus Dinoponera ... [more ▼]

Despite the noxious effects inflicted by Dinoponera ant's envenomation, the information about the biological properties and composition of their venom is still very limited. Ants from the genus Dinoponera are believed to be the world's largest living ants with a body length of 3cm. Their occurrence is restricted to tropical areas of South America. In this work, we study the venom of the giant Dinoponera quadriceps ant collected in 4 different regions of Brazil. By using a combination of complementary mass spectrometric approaches, we aim at: (i) characterizing the venom composition of these ants; (ii) establishing a comparative analysis of the venom from four geographically different regions in Brazil. This approach demonstrates that ant venom is a copious source of new compounds. Several peptides were identified and selected for "de novo sequencing". Since most of the new peptides showed similarities with antimicrobial peptides (AMPs), antimicrobial assays were performed with the purpose of evaluating their activity. In regard to the comparative study of the four regions, we observed not only major differences in the venom compositions, but also that the venoms collected in closest areas are more similar than the ones collected in distant regions. These observations seem to highlight an adaption of the ant venoms to the local environment. Concerning the biological assays, the peptides called Dq-3162 and Da-3177 showed a wide-ranging antimicrobial activity. The characterization of new AMPs with a broad spectrum of activity and different scaffolds may aid scientists to design new therapeutic agents and understand the mechanisms of those peptides to interact with microbial membranes. The results obtained betoken the biotechnological potential of ant's venom. BIOLOGICAL SIGNIFICANCE: For the first time this manuscript describes an extensive proteomics characterization of the D. quadriceps venom. In addition this study reports the variation in venom composition of primitive ants from 4 geographically different areas of Brazil. The results reveal the presence of ~335 compounds for each venom/area and inter-colony variations were observed. 16 new peptides were characterized and 2 of them were synthesized and biologically assayed. These findings highlight the considerable and still unexplored diversity of ant's venom which could be used as valuable research tools in different areas of knowledge. [less ▲]

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See detailCharacterisation of fengycin homologues produced by B. amyloliquefaciens (ET) strain isolated from a salt lake (Eastern Algeria)
Ait Kaki, Asma ULg; Noreddine, K.C.; Kara Ali, M. et al

Poster (2013, November 15)

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See detailUse of on-line flow cytometry for the characterization of physiological behavior in stress conditions during the bioprocess
Brognaux, Alison ULg; Han, Shanshan; Soren, Sorensen et al

Poster (2013, November 15)

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See detailReprogramming of fatty acid and oxylipin synthesis in rhizobacteria-induced systemic resistance in tomato
Mariutto, Martin; Fauconnier, Marie-Laure ULg; Ongena, Marc ULg et al

in Plant Molecular Biology (2013), 84(4-5), 455-476

The rhizobacterium Pseudomonas putida BTP1 stimulates induced systemic resistance (ISR) in tomato. A previous work showed that the resistance is associated in leaves with the induction of the first enzyme ... [more ▼]

The rhizobacterium Pseudomonas putida BTP1 stimulates induced systemic resistance (ISR) in tomato. A previous work showed that the resistance is associated in leaves with the induction of the first enzyme of the oxylipin pathway, the lipoxygenase (LOX), leading to a faster accumulation of its product, the free 13-hydroperoxy octadecatrienoic acid (13-HPOT), 2 days after Botrytis cinerea inoculation. In the present study, we further investigated the stimulation of the oxylipin pathway: metabolites and enzymes of the pathway were analyzed to understand the fate of the 13-HPOT in ISR. Actually the stimulation began upstream the LOX: free linolenic acid accumulated faster in P. putida BTP1-treated plants than in control. Downstream, the LOX products 13-fatty acid hydroperoxides esterified to galactolipids and phospholipids were more abundant in bacterized plants than in control before infection. These metabolites could constitute a pool that will be used after pathogen attack to produce free fungitoxic metabolites through the action of phospholipase A2, which is enhanced in bacterized plants upon infection. Enzymatic branches which can use as substrate the fatty acid hydroperoxides were differentially regulated in bacterized plants in comparison to control plants, so as to lead to the accumulation of the most fungitoxic compounds against B. cinerea. Our study, which is the first to demonstrate the accumulation of an esterified defense metabolite during rhizobacteria-mediated induced systemic resistance, showed that the oxylipin pathway is differentially regulated. It suggests that this allows the plant to prepare to a future infection, and to respond faster and in a more effective way to B. cinerea invasion. [less ▲]

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See detailPrésentation des projets Interreg IVB BIOREFINE et RENEW
Tarayre, Cédric ULg; Delvigne, Frank ULg; Destain, Jacqueline ULg et al

Conference (2013, October 22)

Les projets BioRefine et Renew sont financés par le programme de coopération européen Interreg IVB. Leur but est de promouvoir les transferts de compétences, d'informations et de matières entre les ... [more ▼]

Les projets BioRefine et Renew sont financés par le programme de coopération européen Interreg IVB. Leur but est de promouvoir les transferts de compétences, d'informations et de matières entre les différents pays de la zone européenne du Nord-Ouest. Le projet BioRefine a pour but de récupérer les nutriments (N, P et K) ainsi que les éléments traces métalliques à partir de déchets bien spécifiques: le fumier, le lisier, les digestats de méthanisation et les boues de stations d'épuration. Cette récupération requiert l'élaboration de procédés industriels mis en place après une étude en laboratoire. Le projet Renew, lui, est beaucoup plus général. En ce qui concerne le rôle de Gembloux Agro-Bio Tech dans le projet, le travail sera essentiellement focalisé sur la production d'acide succinique à partir de déchets. Cette production sera assurée par la souche bactérienne Actinobacillus succinogenes. [less ▲]

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See detailProjet Termitofuel: les termites et leurs symbiontes pour mieux valoriser la biomasse ligno-cellulosique
Bauwens, Julien ULg; Tarayre, Cédric ULg; Brasseur, Catherine ULg et al

Poster (2013, October 19)

L’exploitation actuelle de la biomasse ligno-cellulosique, extrêmement abondante sur Terre, est liée à la production de déchets relativement peu valorisables. C’est pourquoi le projet TERMITOFUEL étudie ... [more ▼]

L’exploitation actuelle de la biomasse ligno-cellulosique, extrêmement abondante sur Terre, est liée à la production de déchets relativement peu valorisables. C’est pourquoi le projet TERMITOFUEL étudie la digestion du bois chez les termites, grâce à une approche pluridisciplinaire, en vue d’améliorer la production de bioéthanol de seconde génération. Au sein de l’Unité d’Entomologie Fonctionnelle et Evolutive, l’approche protéomique est employée afin d’identifier les micro-organismes présents dans le tube digestif des termites et caractériser les activités enzymatiques. [less ▲]

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See detailUse of on-line flow cytometry to detect segregation in the microbial population
Brognaux, Alison ULg; Zune, Quentin ULg; Han, Shanshan et al

Poster (2013, October 08)

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See detailANAEROBIC DIGESTION OF ORGANIC WASTES FROM AGRO-FOOD ACTIVITIES IN TUNISIA
Mhiri, F; Hiligsmann, Serge ULg; Sayahi, L. et al

Poster (2013, October 01)

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See detailMONITORING OF ANAEROBIC DIGESTION IN MSW LANDFILLS IN TUNISIA
Mhiri, F.; Hiligsmann, Serge ULg; Sayahi, L. et al

in Proceedings Sardinia 2013 (2013, October)

The monitoring of two controlled landfills in Tunisia was carried out for about 10 years by CITET and CWBI. Both landfills were managed by classical methodology i.e. disposal, compaction and, if any ... [more ▼]

The monitoring of two controlled landfills in Tunisia was carried out for about 10 years by CITET and CWBI. Both landfills were managed by classical methodology i.e. disposal, compaction and, if any, biogas and leachate extraction and treatment. One of them is located near Tunis and the other near Sousse with a warmer climate. They received more than 6,000 and 350 thousand cubic metre of MSW respectively from the two cities. Solid samples were collected by boring at different depths up to 18 m. They were analysed for dry weight and for total organic carbon, nitrogen and (hemi-) cellulose. The boreholes were equipped with 200 mm perforated PEHD tubes for further biogas and leachate sampling and analyses (COD, VFA, CH4 content, …) at different seasons. The results indicate an efficient mesophilic anaerobic digestion in both landfills. The high dry weight content (70 – 92%) of 13 solid samples collected in Sousse landfill contrasts however with the high leachate production in the Tunis landfill, filling about completely the majority of boreholes. The results of this monitoring confirm the trends formerly described about biological activity and environmental impact of landfills in Tunisia. Moreover a 200 L pilot-scale anaerobic digester was operated for about 3 years with solid wastes from Tunis landfill to assess the evolution of moisture content and organic matter. [less ▲]

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