References of "Fauconnier, Marie-Laure"
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See detailGene expression of the lipoxygenase pathway in a tomato species tolerant to salt stress
Ghars, Mohamed Ali ULg; Muhovski, Y.; Ghanem, M. et al

Poster (2010)

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See detailOxylipin profiles of Solanum esculentum and Solanum pennellii under salt stress conditions
Ghars, Mohamed Ali ULg; Frettinger, P.; Ghanem, M. E. et al

Poster (2009, June 05)

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See detailPilot scale biotransformation of vegetal oil into natural green note flavor using sugar beet leaves as sources of hydroperoxide lyase
Gigot, Cédric ULg; Ongena, Marc ULg; Fauconnier, Marie-Laure ULg et al

Poster (2009, June 02)

Natural green note aromas (GLVs) are highly attractive flavors commonly used in the food industry. These are produced in extremely low levels upon physiological stress in plant organs of any sort. This ... [more ▼]

Natural green note aromas (GLVs) are highly attractive flavors commonly used in the food industry. These are produced in extremely low levels upon physiological stress in plant organs of any sort. This weak sporadic presence entails a very expensive extraction step to obtain pure GLVs. Therefore catalytic biotransformations of fatty acid sources, the initial substrate for GLVs, have been developed. Enzymatic defense pathways and particularly the LOX pathway produce the major part of GLVs. Unlike GLV molecules that are emitted in the atmosphere, the enzymes are extractible from the plant material. Thus, a combination of plant enzyme extracts and substrate preparations provides all the ingredients for GLV production. Besides, sugar beet leaves present high levels of hydroperoxide lyase among plant sources and are available in large amounts during three months. In this enzymatic pathway, fatty acids are successively transformed by lipase, lipoxygenase and hydroperoxide lyase into aldehydes and alcohols, final compounds of GLVs pathway. Limiting and problematic steps occur with the action of hydroperoxide lyase, when enzymatic catalysis is followed by an enzyme destabilization. Alternative substrates bind irreversibly to the heme group of the enzyme and end the reaction. This poster briefly describes the development of a complete bioprocess for natural GLV production, from hydrolysis to purification. A high level of biotransformation could be achieved using optimum experimental conditions and a cheap source of plant materials. [less ▲]

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See detailDetermination of phospholipids extracted from Tsukamurella paurometabola C-924 after freeze-drying and during the subsequent storage.
Coulibaly, Ibourahema ULg; Yao, Amenan Anastasie ULg; Dubois Dauphin, Robin ULg et al

Poster (2009, April 01)

The total lipids of Tsukamurella paurometabola C-924 were analysed after freeze-drying. Seven individual lipids classes were identified namly neutral lipids (NLs), fatty acids (FAs), phospholipids (PLs ... [more ▼]

The total lipids of Tsukamurella paurometabola C-924 were analysed after freeze-drying. Seven individual lipids classes were identified namly neutral lipids (NLs), fatty acids (FAs), phospholipids (PLs), sterol ester (SEs), triglycerides (TGs), diglycerides (DGs) and monoglycerides (MGs). The principal fatty acids identified in most lipid classes were palmitic (C16:0), palmitoleic (C16:1), oleic (C18:1), linoleic (C18:2), and linolenic (C18:3). PLs were the major constituents and accounted for 50-60% of the total lipids. PLs were fractionated. . PLs of Tsukamurella paurometabola content phosphatidic acid (PA), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC), sphingomyelin (SM), lysophosphatidylcholine (LPC) and phosphatidylglycerol (PG). It was observed that PG had the highest proportion at most points relative to other PLs and was the predominant component of PLs (30%-56%). Evolution of individual rate was followed during stored at 20°C and 40°C with or without lithothamne400®, respectively. [less ▲]

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See detailSurvival of Freeze-dried Leuconostoc mesenteroides and Lactobacillus plantarum Related to Their Cellular Fatty Acids Composition during Storage
Coulibaly, Ibourahema ULg; Yao, Amenan Anastasie ULg; Lognay, Georges ULg et al

in Applied Biochemistry and Biotechnology (2009), 157(1), 70-84

Lactic acid bacteria strains Lactobacillus plantarum CWBI-B534 and Leuconostoc ssp. mesenteroïdes (L. mesenteroïdes) Kenya MRog2 were produced in bioreactor, concentrated, with or without cryoprotectants ... [more ▼]

Lactic acid bacteria strains Lactobacillus plantarum CWBI-B534 and Leuconostoc ssp. mesenteroïdes (L. mesenteroïdes) Kenya MRog2 were produced in bioreactor, concentrated, with or without cryoprotectants. In general, viable population did not change significantly after freeze-drying (p>0.05). In most cases, viable population for cells added with cryoprotectants was significantly lower than those without (p<0.05). Cellular fatty acids (CFAs) from the two strains in this study were analyzed before and after freeze-drying. Six CFAs were identified, namely, palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1), linoleic (C18:2), and linolenic (C18:3) acids were identified. Four of them, C16:0, C16:1, C18:0, and C18:1, make up more than 94% or 93% of the fatty acids in L. mesenteroides and L. plantarum, respectively, with another one, namely, C18:3, making a smaller (on average 5–6%, respectively) contribution. The C18:2 contributed very small percentages (on average≤1%) to the total in each strain. C16:0 had the highest proportion at most points relative to other fatty acids. Moisture content and water activity (a w) increased significantly during the storage period. It was observed that C16:1/C16:0, C18:0/C16:0 and C18:1/C16:0 ratios for freeze-dried L. mesenteroides or L. plantarum, with or without cryoprotectants, did not change significantly during the storage period. According to the packaging mode and storage temperatures, C18:2/C16:0 and C18:3/C16:0 ratios for freeze-dried L. mesenteroides and L. plantarum with or without cryoprotectants decreased as the storage time increased. However, a higher C18:2/C16:0 or C18:3/C16:0 ratio for L. mesenteroides and L. plantarum was noted in the freeze-dried powder held at 4 °C or under vacuum and in dark than at 20 °C or in the presence of oxygen and light [less ▲]

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See detailYlang-ylang (Cananga odorata (Lam.) Hook. & Thoms. var. genuina) essential oils from Comoros Islands: characterization and variability
Benini, Céline ULg; Wathelet, Jean-Paul ULg; du Jardin, Patrick ULg et al

Poster (2009)

The Union of the Comoros is the world’s biggest producer of ylang-ylang essential oils. Comorian ylang-ylang also provides the most valuable essential oil that can be found on international market. This ... [more ▼]

The Union of the Comoros is the world’s biggest producer of ylang-ylang essential oils. Comorian ylang-ylang also provides the most valuable essential oil that can be found on international market. This product represents a high percentage of Comoros’ annual currency. Ylang-ylang essential oil is obtained by fractionned hydrodistillation or steam distillation of Cananga odorata fresh flowers. This oil is commercialized in five different quality grades (extra S; extra; I; II; III) which possess their own physicochemical properties. [less ▲]

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See detailLipoxygenase pathway and antioxidant system in salt-stressed tomato seedlings (Lycopersicon esculentum Mill.).
Delaplace, Pierre ULg; Frettinger, P.; Ghanem, M. E. et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2009), 13

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See detailPotato (Solanum Tuberosum L.) Tuber Ageing Induces Changes In The Proteome And Antioxidants Associated With The Sprouting Pattern
Delaplace, Pierre ULg; Fauconnier, Marie-Laure ULg; Sergeant, K. et al

in Journal of Experimental Botany (2009), 60(4), 1273-1288

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See detailWheat root ecophysiology: understanding communication between wheat root system and soil microorganisms.
Delaplace, Pierre ULg; d'Ans, Séverine ULg; Wathelet, Jean-Paul ULg et al

Poster (2009)

Studies leading to a better understanding of the mechanisms involved in the communication between soil microorganisms and root system can potentially lead to improved fertility management strategies. Up ... [more ▼]

Studies leading to a better understanding of the mechanisms involved in the communication between soil microorganisms and root system can potentially lead to improved fertility management strategies. Up to now, the characterization of such interactions has been mainly focused on root exsudates but volatile organic compounds (VOC) also play a role as chemical messengers in positive interactions occurring in the rhizosphere. We aim to better understand the VOC-mediated chemical ecophysiology of soil. Wheat (Triticum aestivum L.) was chosen in this project based on its importance for food production and industrial applications. [less ▲]

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See detailAttacks by a piercing-sucking insect (Myzus persicae Sultzer) or a chewing insect (Leptinotarsa decemlineata Say) on potato plants (Solanum tuberosum L.) induce differential changes in volatile compound release and oxylipin synthesis
Gosset, Virginie; Harmel, Nicolas; Goebel, Cornelia et al

in Journal of Experimental Botany (2009), 60(4), 1231-1240

Plant defensive strategies bring into play blends of compounds dependent on the type of attacker and coming from different synthesis pathways. Interest in the field is mainly focused on volatile organic ... [more ▼]

Plant defensive strategies bring into play blends of compounds dependent on the type of attacker and coming from different synthesis pathways. Interest in the field is mainly focused on volatile organic compounds (VOCs) and jasmonic acid (JA). By contrast, little is known about the oxidized polyunsaturated fatty acids (PUFAs), such as PUFA-hydroperoxides, PUFA-hydroxides, or PUFA-ketones. PUFA-hydroperoxides and their derivatives might be involved in stress response and show antimicrobial activities. Hydroperoxides are also precursors of JA and some volatile compounds. In this paper, the differential biochemical response of a plant against insects with distinct feeding behaviours is characterized not only in terms of VOC signature and JA profile but also in terms of their precursors synthesized through the lipoxygenase (LOX)-pathway at the early stage of the plant response. For this purpose, two leading pests of potato with distinct feeding behaviours were used: the Colorado Potato Beetle (Leptinotarsa decemlineata Say), a chewing herbivore, and the Green Peach Aphid (Myzus persicae Sulzer), a piercing-sucking insect. The volatile signatures identified clearly differ in function with the feeding behaviour of the attacker and the aphid, which causes the smaller damages, triggers the emission of a higher number of volatiles. In addition, 9-LOX products, which are usually associated with defence against pathogens, were exclusively activated by aphid attack. Furthermore, a correlation between volatiles and JA accumulation and the evolution of their precursors was determined. Finally, the role of the insect itself on the plant response after insect infestation was highlighted. [less ▲]

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See detailImpact of polyunsaturated fatty acid degradation on survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 during storage
Yao, Amenan Anastasie ULg; Coulibaly, Ibourahema ULg; Lognay, Georges ULg et al

in Applied Microbiology & Biotechnology (2008), 79(6), 1045-1052

Abstract The impact of polyunsaturated fatty acid (PUFA) degradation on the survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 was investigated over 90-days storage at 4 ... [more ▼]

Abstract The impact of polyunsaturated fatty acid (PUFA) degradation on the survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 was investigated over 90-days storage at 4 °C or 20 °C in vacuumsealed aluminium foil or glass tubes with two water activities (aw=0.11 or 0.23). Colony counts, acidification activity (% lactic acid/g), linoleic/palmitic (18:2/16:0) or linolenic/palmitic (18:3/16:0) ratio by gas chromatography and 18:2 or 18:3 oxylipins by reversed phase-high performance liquid chromatography were determined. The viable cells, acidification activity and 18:2/16:0 or 18:3/ 16:0 ratio decreased as the storage time increased. The survival, acidification activity and 18:2/16:0 or 18:3/16:0 ratio were greatest for the freeze-dried strain held in vacuum-sealed aluminium foil at 4 °C. The 18:2/16:0 or 18:3/16:0 ratio decrease was correlated with the accumulation of 18:2 or 18:3 oxylipins during storage in glass tubes. Hydroperoxy PUFAs, hydroxy PUFAs, divinyl ether PUFAs and oxo PUFAs were the main oxylipins identified. A large decrease in the 18:2/16:0 or 18:3/16:0 ratio and a rapid accumulation of oxylipins during storage might be enough to cause high cell death and loss of metabolic activity. These results provide further experimental support for the hypothesis that lipid oxidation and survival or activity of freeze-dried bacteria might be related. [less ▲]

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

in Biotechnology Letters (2008), 30(6), 1115-9

Hydroperoxide lyase activity was found in sugar beet leaves. Its optimum pH and temperature were, respectively, 6.7 and 22 degrees C. Under these conditions, conversion of linolenic acid 13-hydroperoxide ... [more ▼]

Hydroperoxide lyase activity was found in sugar beet leaves. Its optimum pH and temperature were, respectively, 6.7 and 22 degrees C. Under these conditions, conversion of linolenic acid 13-hydroperoxide to cis-3-hexenal with a maximum yield of 80% was reached after only 2 min. The stability of cis-3-hexenal was improved by acidifying the reaction medium. Based on these studies, a bioprocess producing green-note aldehydes in a laboratory-scale was achieved. [less ▲]

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