References of "Ongena, MARC"
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See detailSugar beet : a source of biofuel an chemicals.
Destain, Jacqueline ULg; Gigot, Cédric ULg; Fauconnier, Marie-Laure ULg et al

Poster (2007, June)

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See detailSugar beet leaves as source of green notes.
Gigot, Cédric ULg; Rabetafika, Holy-Nadia ULg; Fauconnier, Marie-Laure ULg et al

Poster (2007, June)

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See detailThe systemic resistance induced in tomato by a non-pathogenic Pseudomonas strain is associated with the stimulation of the lipoxygenase pathway
Adam, Akram; Duby, Franceline ULg; Ongena, MARC ULg et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2007), 30

Root treatment by the non-pathogenic Pseudomonas putida strain BTP1 reduced by 34% the disease caused by Botrytis cinerea on tomato leaves. This induced systemic resistance phenomenon is associated both ... [more ▼]

Root treatment by the non-pathogenic Pseudomonas putida strain BTP1 reduced by 34% the disease caused by Botrytis cinerea on tomato leaves. This induced systemic resistance phenomenon is associated both with the accumulation of fungitoxic material and with the stimulation of the lipoxygenase pathway in infected leaves. More precisely, we observed a consistent change in the expression of a new tomloxF gene in the leaves from BTP1-treated plants as far as the pathogen is introduced. This suggests that the roots were primed and reacted locally to colonization by bacteria and that defense-related gene expression is turned on systemically upon pathogen perception [less ▲]

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See detailPGPR-induced systemic resistance: activity of amphiphilic elicitors and structural analogues on different plant species
Jourdan, Emmanuel ULg; Ongena, MARC ULg; Adam, Akram et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2007), 30

Some non pathogenic microorganisms can induce disease resistance mechanisms expressed systemically in the host plant thereby rendering it less susceptible to further attack by pathogens. In this study, we ... [more ▼]

Some non pathogenic microorganisms can induce disease resistance mechanisms expressed systemically in the host plant thereby rendering it less susceptible to further attack by pathogens. In this study, we have investigated the role of bacterial compounds as elicitors of the induced systemic resistance. Lipopeptides, especially surfactin and fengycin, produced by Bacillus subtilis strains are able to stimulate bean and tomato plants and decrease the impact of subsequent pathogen infection. Preliminary experiments on tobacco cells showed that surfactine induces some modifications in the phenylpropanoid pathway. Amphiphilic properties of lipopeptides and NABD, the elicitor isolated from Pseudomonas putida strain BTP1, could be responsible for their activities on plant cells [less ▲]

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See detailSugar beet leaves as source of lyase in bioprocess producing green note aldehydes
Rabetafika, Holy-Nadia ULg; Gigot, Cédric ULg; Fauconnier, Marie-Laure ULg et al

Poster (2007)

Sugar beet leaves were used as source of lyase in a biocatalytic process for the production of C6-aldehydes. Their hydroperoxide lyase activity was revealed important. The optimum values of pH and ... [more ▼]

Sugar beet leaves were used as source of lyase in a biocatalytic process for the production of C6-aldehydes. Their hydroperoxide lyase activity was revealed important. The optimum values of pH and temperature for reactions were respectively 6.7 and 22 °C. A simple and fast process providing high molar conversion of hydroperoxides to aldehydes is proposed. The yield of the main product cis-3-hexenal reached 80% after only 2 min and was stabilised by acidifying the reaction medium to pH 2. [less ▲]

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See detailSurfactin and fengycin lipopeptides of Bacillus subtilis as elicitors of induced systemic resistance in plants
Ongena, MARC ULg; Jourdan, Emmanuel ULg; Adam, Akram ULg et al

in Environmental Microbiology (2007), 9(4), 1084-1090

Multiple strains of Bacillus spp. were demonstrated to stimulate plant defence responses. However, very little is known about the nature of molecular determinants secreted by these Gram-positive bacteria ... [more ▼]

Multiple strains of Bacillus spp. were demonstrated to stimulate plant defence responses. However, very little is known about the nature of molecular determinants secreted by these Gram-positive bacteria that are responsible for the elicitation of the induced systemic resistance (ISR) phenomenon. This study shows that the lipopeptides surfactins and fengycins may be involved in this elicitation process. In bean, pure fengycins and surfactins provided a significant ISR-mediated protective effect on bean plants, similar to the one induced by living cells of the producing strain S499. Moreover, experiments conducted on bean and tomato plants showed that overexpression of both surfactin and fengycin biosynthetic genes in the naturally poor producer Bacillus subtilis strain 168 was associated with a significant increase in the potential of the derivatives to induce resistance. In tomato cells, key enzymes of the lipoxygenase pathway appeared to be activated in resistant plants following induction by lipopeptide overproducers. To our knowledge, such lipopeptides constitute a novel class of compounds from non-pathogenic bacteria that can be perceived by plant cells as signals to initiate defence mechanisms. [less ▲]

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See detailRole of lipopeptides in the biological control activity of Bacillus subtilis
Jourdan, Emmanuel ULg; Ongena, Marc ULg; Adam, A. et al

Poster (2006, May)

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See detailPhysicochemical And Biochemical Characterization Of Non-Biodegradable Cellulose In Miocene Gymnosperm Wood From The Entre-Sambre-Et-Meuse, Southern Belgium
Lechien, Valérie; Rodriguez, Christian; Ongena, MARC ULg et al

in Organic Geochemistry (2006), 37(11), 1465-1476

Specimens of Miocene fossil wood from the Entre-Sambre-et-Meuse karsts (southern Belgium) were examined using physicochemical and biochemical techniques in order to understand the reasons for the ... [more ▼]

Specimens of Miocene fossil wood from the Entre-Sambre-et-Meuse karsts (southern Belgium) were examined using physicochemical and biochemical techniques in order to understand the reasons for the exceptional preservation of these fossilized remains after 15 million years. Structural and chemical changes were assessed by comparing the structural features of the fossil samples with those of their modern counterpart, Metaseguoia. Solid state C-13 nuclear magnetic resonance (NMR) and microscopic analysis showed good preservation of the cellulose structure in the fossil wood from the Florennes peat deposit. Despite the substantial cellulose fraction available in the fossil tissue, an enzymatic degradation test and a biochemical methane potential assay showed that the fossil cellulose could not be degraded by cellulases and anaerobic microorganisms usually involved in the biodegradation of organic matter. Moreover, the cellulose structure (crystallinity and surface area) seemed to have no effect on cellulose biodegradability in these Miocene fossil wood samples. On the basis of our observations, we suggest that the presence of a modified lignin structure could greatly influence cellulose preservation/biodegradability. [less ▲]

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See detailRole of lipopeptides in the biological control activity of Bacillus subtilis
Ongena, Marc ULg; Jourdan, E.; Adam, A. et al

Conference (2006)

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See detailPhysiological and physico-chemical factors modulating ISR elicitor production by Pseudomonas putida
Jourdan, Emmanuel ULg; Ongena, MARC ULg; Adam, Akram et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2006), 29(2)

Abstract: A better understanding of biotic and environmental factors that regulate the production of active metabolites by beneficial rhizobacteria is crucial for optimising biocontrol under pratical ... [more ▼]

Abstract: A better understanding of biotic and environmental factors that regulate the production of active metabolites by beneficial rhizobacteria is crucial for optimising biocontrol under pratical conditions. In this study, we wanted to evaluate the effect of some parameters on the production of the plant defence elicitor synthesized by Pseudomonas putida BTP1. This molecule is clearly dependant of the secondary metabolism and chemostat experiments showed that the elicitor is more efficiently produced at a very low cell growth rate. On another hand, the presence of free amino acids in the medium is necessary to obtain an optimal NABD production. A specific positive effect of phenylalanine was evidenced in pulsed continuous cultures suggesting that this residue could play a role as a precursor and/or act as a regulator in the biosynthetic pathway. [less ▲]

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See detailProduction and down-stream processing of an extracellular lipase from the yeast Yarrowia lipolytica
Fickers, Patrick ULg; Ongena, MARC ULg; Destain, Jacqueline ULg et al

in Enzyme & Microbial Technology (2006), 38(6), 756-759

Lipase constitutes an interesting class of enzyme with many biotechnological applications. However, the development of a fruitful process must be set up to obtained a product compatible with the ... [more ▼]

Lipase constitutes an interesting class of enzyme with many biotechnological applications. However, the development of a fruitful process must be set up to obtained a product compatible with the industrial and commercial needs. Here, we report the development of such a process for the extracellular lipase secreted by the yeast Yarrowia lipolytica. The enzyme production, carried out in a 2000 L bioreactor, led to a lipase activity of approximately 1100 U mL(-1) after 53 h of fermentation. The post-culture treatment, consisting of a centrifugation, a filtration and an ultra-filtration steps, led to 15-fold volume reduction and a 8-fold increased of the lipase activity. Finally, addition of 12% of milk powder and 3% of gum arabic before spray-drying dehydration led to a stable powder with a lipolytic activity of 37,500 U g D.W.(-1). (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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