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See detailLipase from Yarrowia lipolytica.
Destain, Jacqueline ULg; Weber, D.; Thonart, Philippe ULg

in Mededelingen van de Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen (Rijksuniversiteit te Gent) (1997), 62(4a),

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See detailLipase production by Yarrowia lipolytica: study of the effects of operating conditions by factorial design of experiments
Lopes, M.; Gomes, I.; Araújo, C. et al

in European Symposium on Biochemical Engineering Science : book of abstracts”. [S.l. : s.n. 2006] (2006, August)

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See detailLipase production in Yarrowia lipolytica overproducing mutants.
Fickers, Patrick ULg; Nicaud, J. M.; Destain, Jacqueline ULg et al

Poster (2002, July)

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See detailLipase synthesis of fatty acid sugar esters in pure ionic liquids
Galonde, Nadine ULg

Poster (2010, October 14)

Sugar fatty acid esters are broadly consumed in many commercial applications and their synthesis gained a considerable interest since they are biodegradable, tasteless, odorless, non-toxic and non ... [more ▼]

Sugar fatty acid esters are broadly consumed in many commercial applications and their synthesis gained a considerable interest since they are biodegradable, tasteless, odorless, non-toxic and non-irritant. Ionic liquids are organic salts entirely comprised of ions with a melting point below 100°C. This new category of solvent may allow the enzymatic synthesis of sugar fatty acid ester to go toward a “greener” process. Within the purpose of using “green” systems for synthesis of glycosylated compounds, studies on the use of ionic liquids to obtain fatty acid sugar esters with carbohydrates coming from lignocellulosic material as substrates was carried out. The enzymatic synthesis of mannose myristate ionic liquids as enzymatic medium and the yield obtained will be presented in our poster. [less ▲]

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See detailLipase-assisted synthesis of potential bio-based surfactants starting from lignocellulosic carbohydrates
Richard, Gaetan ULg; Nott, Katherine ULg; Paquot, Michel ULg et al

Poster (2010, April)

Surfactants constitute an important class of compounds with a lot of applications, especially in the food and beverage industries (emulsion forming and stabilization, antiadhesive and antimicrobial ... [more ▼]

Surfactants constitute an important class of compounds with a lot of applications, especially in the food and beverage industries (emulsion forming and stabilization, antiadhesive and antimicrobial activities)1. With the prospect of synthesising new active compounds, white biotechnology offers efficient tools. Indeed, the use of enzymes as biocatalysts provides an interesting synthetic route in comparison to the chemical way that often requires high reaction temperatures and suffers from a lack of specificity, resulting in complex mixtures. Among all the biocatalysts available, lipases represent a class of industrial interest 2,3. In parallel, the starting material is also an important parameter : due to the depletion of petroleum reserves, its ever increasing price and various environmental aspects, the use of renewable or biomass resources is inevitable. Within the frame of a biorefinery project, we focused on the lipase-assisted modification of uronic acids. These carbohydrates can be obtained from lignocellulosic material, and, in the presence of fatty alcohols, the Candida antarctica lipase B catalyses the synthesis of amphiphilic compounds. Owing to the initial conditions used and the addition of co-solvents, we optimized the synthesis of these bio-based potential surfactants, and obtained a panel of various structures depending to the acyl acceptor used. The poster will present the details of these syntheses. [less ▲]

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See detailLipase-catalyzed interesterification of butterfat with rapeseed oil: new approaches for the monitoring of the reaction.
Hanon, Emilien ULg; Aguedo, Mario ULg; Danthine, Sabine ULg et al

Poster (2007)

Butterfat (BF) is one main source of diet fats. However, it has been less and less well perceived due to its poor spreadability when refrigerated and cholesterol and saturated fatty acids, promoters of ... [more ▼]

Butterfat (BF) is one main source of diet fats. However, it has been less and less well perceived due to its poor spreadability when refrigerated and cholesterol and saturated fatty acids, promoters of coronary heart diseases. Thus, consumer’s demand for healthy palatable fat spreads with good development of modified butter-based spreads. One ordinary method used by manufacturers for such modifications is enzymatic interesterification of a lipase to restructure triacylglycerides (TAG), i.e. to induce the exchange of fatty acid residues amongst glycerol backbones. This leads to changes in TAG species and in physical properties of the fat, namely in solid fat content (SFC) and in melting profile. Rapeseed oil (RO) contains a large amount of oleic acid and has significant contents of linoleic and linolenic acids, i.e. a high global content of unsaturation-rich residues. Thus, EIE of BF with RO may bring nutritional improvements to the reaction product, when compared to BF alone. The EIE of BF and canola oil (a low-erucic acid RO) catalyzed by the immobilized sn-1,3 specific Rhizopus arrhizus lipase in solvent-free batch and micro-aqueous systems, was previously studied. The aim of the present study was first to assess the evolution of chemical, physical and thermal modifications occurring during solvent-free batch EIE of BF and RO, with the use of lipozyme TL IM. The evolution of TAG profiles, interesterification degree, dropping point, solid fat content and free fatty acids was monitored during the reaction, especially during the first hours. Differential scanning calorimetry was also applied to follow the formed product. Then the establishment of relations between the DP and differential scanning calorimetry data and the interesterification degree was emphasized. [less ▲]

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See detailLipase-catalyzed synthesis of L-cysteine glucosyl esters in organic media
Valepyn, Emmanuel ULg; Nys, Joël ULg; Richel, Aurore ULg et al

in Biocatalysis & Biotransformation (2011), 29(1), 25-30

New sugar amino acids were synthesized by enzymatic esterification of D -glucose with L -cysteine using immobilized lipase B from Candida antarctica in a mixed solvent system composed of 2-methyl-2 ... [more ▼]

New sugar amino acids were synthesized by enzymatic esterification of D -glucose with L -cysteine using immobilized lipase B from Candida antarctica in a mixed solvent system composed of 2-methyl-2-butanol and dimethyl sulfoxide. Addition of small quantities of water to the medium improved the glucose conversion yield by a factor of two. [less ▲]

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See detailLIPASES FROM PSYCHROTROPHIC ANTARCTIC BACTERIA
Feller, Georges ULg; Thiry, M.; Arpigny, J. L. et al

in FEMS Microbiology Letters (1990), 66(1-3), 239-243

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See detailThe lipases from Yarrowia lipolytica: genetics, production, regulation, biochemical characterization and biotechnological applications.
Fickers, Patrick ULg; Marty, Alain; Nicaud, Jean Marc

in Biotechnology advances (2011), 29(6), 632-44

Lipases are serine hydrolases that catalyze in nature the hydrolysis of ester bonds of long chain triacylglycerol into fatty acid and glycerol. However, in favorable thermodynamic conditions, they are ... [more ▼]

Lipases are serine hydrolases that catalyze in nature the hydrolysis of ester bonds of long chain triacylglycerol into fatty acid and glycerol. However, in favorable thermodynamic conditions, they are also able to catalyze reactions of synthesis such as esterification or amidation. The non-conventional yeast Yarrowia lipolytica possesses 16 paralogs of genes coding for lipase. However, little information on all those paralogs has been yet obtained and only three isoenzymes, namely Lip2p, Lip7p and Lip8p have been partly characterized so far. Microarray data suggest that only a few of them could be expressed and that lipase synthesis seems to be dependent on the fatty acid or oil used as carbon source confirming the high adaptation of Y. lipolytica to hydrophobic substrate utilization. This review focuses on the biochemical characterization of those enzymes with special emphasis on the Lip2p lipase which is the isoenzyme mainly synthesized by Y. lipolytica. Crystallographic data highlight that this latter is a lipase sensu stricto with a lid covering the active site of the enzyme in its closed conformation. Recent findings on enzyme conditioning in dehydrated or liquid formulation, in enzyme immobilization by entrapment in natural polymers from either organic or mineral origins are also discussed together with long-term storage strategies. The development of various biotechnological applications in different fields such as cheese ripening, waste treatment, drug synthesis or human therapeutics is also presented. [less ▲]

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See detailLes lipases sont des hydrolases atypiques : principales caractéristiques et applications
Fickers, Patrick ULg; Destain, Jacqueline ULg; Thonart, Philippe ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2008), 12(2), 119-130

Due to their kinetic and substrate specificities, triacylglycerol acyl-hydrolases or lipases are atypical enzymes. In function of their microenvironment, lipases are able to act as hydrolases in aqueous ... [more ▼]

Due to their kinetic and substrate specificities, triacylglycerol acyl-hydrolases or lipases are atypical enzymes. In function of their microenvironment, lipases are able to act as hydrolases in aqueous solution or as biocatalysts in organic synthesis. As hydrolases, they are responsible of the triglycerids catabolism into fatty acids and glycerol. In many organisms, this reaction plays a major role in the fat and lipid metabolism. In addition, lipases are also able to hydrolyse phospholipids and cholesterol esters. In organic solvent, lipases could catalyse reactions such as esterifications, acidolysis or alcoolysis with enantio-, regio- and chimioselectivity. Lipases form a mixed class of enzyme due to their animal, vegetal or microbial origins. All those properties led to the development of many applications in the food and chemical industries but also in the medical and therapeutic field. [less ▲]

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See detailLipid and oxylipin profile during storage of potato tubers
Fauconnier, Marie-Laure ULg; Welti, R.; Delaplace, Pierre ULg et al

Poster (2004, June 01)

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See detailLipid and oxylipin profile during storage of potato tubers
Fauconnier, Marie-Laure ULg; Welti, R.; Delaplace, Pierre ULg et al

Poster (2004, June 03)

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See detailLipid And Oxylipin Profiles During Aging And Sprout Development In Potato Tubers (Solanum Tuberosum L.)
Fauconnier, Marie-Laure ULg; Welti, R.; Blee, E. et al

in Biochimica et Biophysica Acta-Molecular and Cell Biology of Lipids (2003), 1633(2),

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See detailLipid and Protein Composition of the Mammary Tumour Virus and the Milk Fat-Globule Membrane Isolated from the milk of infected Mice
Calberg-Bacq, C. M.; François, C.; Gosselin, L. et al

in Biochemical Society Transactions (1975)

Milk fat globule membranes and mammary tumour virus particles have been obtained from the milk of a swiss albino mice strain. Comparative biochemistry shows that these two structures differ significantly ... [more ▼]

Milk fat globule membranes and mammary tumour virus particles have been obtained from the milk of a swiss albino mice strain. Comparative biochemistry shows that these two structures differ significantly in the phospholipid, polypeptide and glycopeptide patterns and enzymatic activities. However, the lipid profile and the morphology of both structures suggest a filiation with the plasma membrane. Density fractions obtained from the crude virus preparation have been thoroughly investigated. The results sugget that most of these fractions represent degraded virus and/or atipycal virus assembly. [less ▲]

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See detailLIPID INTERACTION PROPERTIES OF NOVEL RHAMNOLIPIDS
Nasir, Mehmet Nail ULg; Crowet, Jean-Marc ULg; Lins, Laurence ULg et al

Conference (2013, November)

Biosurfactants which are surface active molecules produced by micro-organisms present a wide structural diversity (glycolipids, lipoaminoacids, lipopeptides, polymers,...) and numerous advantages compared ... [more ▼]

Biosurfactants which are surface active molecules produced by micro-organisms present a wide structural diversity (glycolipids, lipoaminoacids, lipopeptides, polymers,...) and numerous advantages compared to their chemically synthesized counterparts. Among glycolipids, rhamnolipids which are secondary metabolites produced mainly by strains of Pseudomonas aeruginosa, have drawn particular attention as they have several interesting biological properties such as antimicrobial, antiphytoviral, zoosporicidal and plant defense elicitor activities [1-3]. It is generally recognized that these activities must be linked to the interaction of these molecules with constituents of biological membranes [4] but the detailed mechanism is far from being fully understood. In our laboratory, new rhamnolipids with various chain lengths and with or without a terminal carboxylic acid function were obtained via the development of a synthesis procedure consisting of two biocatalyzed steps involving naringinase and lipase [5]. The objective of this work was to investigate their interaction with model membranes in relation with their structure in order to give insight about the mechanism of their biological action. A range of complementary experimental and modelling methods was used to analyze their interaction with membrane models. Results reveal differential interaction with lipids according to the structure of the rhamnolipid. The nature of the lipid is also a key parameter for the ınteractions. [less ▲]

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See detailThe lipid phosphatase SHIP2 controls insulin sensitivity
Clément, S.; Krause, U.; Desmedt, F. et al

in Nature (2001), 409

Insulin is the primary hormone involved in glucose homeostasis, and impairment of insulin action and/or secretion has a critical role in the pathogenesis of diabetes mellitus. Type-II SH2-domain ... [more ▼]

Insulin is the primary hormone involved in glucose homeostasis, and impairment of insulin action and/or secretion has a critical role in the pathogenesis of diabetes mellitus. Type-II SH2-domain-containing inositol 5-phosphatase, or 'SHIP2', is a member of the inositol polyphosphate 5-phosphatase family. In vitro studies have shown that SHIP2, in response to stimulation by numerous growth factors and insulin, is closely linked to signalling events mediated by both phosphoinositide-3-OH kinase and Ras/mitogen-activated protein kinase. Here we report the generation of mice lacking the SHIP2 gene. Loss of SHIP2 leads to increased sensitivity to insulin, which is characterized by severe neonatal hypoglycaemia, deregulated expression of the genes involved in gluconeogenesis, and perinatal death. Adult mice that are heterozygous for the SHIP2 mutation have increased glucose tolerance and insulin sensitivity associated with an increased recruitment of the GLUT4 glucose transporter and increased glycogen synthesis in skeletal muscles. Our results show that SHIP2 is a potent negative regulator of insulin signalling and insulin sensitivity in vivo [less ▲]

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See detailLipid raft targeting of hematopoietic protein tyrosine phosphatase by protein kinase C theta-mediated phosphorylation.
Nika, Konstantina; Charvet, Celine; Williams, Scott et al

in Molecular & Cellular Biology (2006), 26(5), 1806-16

Protein kinase C theta (PKC theta) is unique among PKC isozymes in its translocation to the center of the immune synapse in T cells and its unique downstream signaling. Here we show that the hematopoietic ... [more ▼]

Protein kinase C theta (PKC theta) is unique among PKC isozymes in its translocation to the center of the immune synapse in T cells and its unique downstream signaling. Here we show that the hematopoietic protein tyrosine phosphatase (HePTP) also accumulates in the immune synapse in a PKC theta-dependent manner upon antigen recognition by T cells and is phosphorylated by PKC theta at Ser-225, which is required for lipid raft translocation. Immune synapse translocation was completely absent in antigen-specific T cells from PKC theta-/- mice. In intact T cells, HePTP-S225A enhanced T-cell receptor (TCR)-induced NFAT/AP-1 transactivation, while the acidic substitution mutant was as efficient as wild-type HePTP. We conclude that HePTP is phosphorylated in the immune synapse by PKC theta and thereby targeted to lipid rafts to temper TCR signaling. This represents a novel mechanism for the active immune synapse recruitment and activation of a phosphatase in TCR signaling. [less ▲]

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