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See detailModification génétique de la levure pour maîtriser la beta-oxydation: exemple de la production de lactone par Yarrowia lipolytica
Waché, Y.; Aguedo, Mario ULg; Marchal, E. et al

in Les outils biologiques dans les procédés et les techniques d'analyse...: conférences et communications scientifiques (2001, March)

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See detailModification génétique de la levure Yarrowia lipolytica pour maîtriser la β-oxydation
Waché, Y.; Aguedo, Mario ULg; LeDall, M.-T. et al

in Journal de la Société de Biologie (2001), 195(4), 459-459

Les biotechnologies font régulièrement appel à la β-oxydation pour produire des composés à haute valeur ajoutée ou dépolluer des effluents industriels. Cette voie métabolique est difficile à maîtriser car ... [more ▼]

Les biotechnologies font régulièrement appel à la β-oxydation pour produire des composés à haute valeur ajoutée ou dépolluer des effluents industriels. Cette voie métabolique est difficile à maîtriser car elle implique un nombre réduit d'enzymes pour une voie très longue. En particulier, la production d'intermédiaires réactionnels est délicate car les enzymes de la voie de reconsommation sont souvent les mêmes que celles impliquées dans la production. Ainsi, la production de γ-décalactone à partir de ricinoléate de méthyle chez Y. lipolytica implique la β-oxydation (Endrizzi et al., 1996). Cette levure est un bon modèle pour étudier le métabolisme des acides gras car elle possède cinq acyl-CoA oxydases (Aox) catalysant la première étape de la β-oxydation (Wang et al., 1999). L'effet d'une invalidation des gènes codant pour les Aox a été étudié sur la production de γ-décalactones. En fonction des Aox présentes dans les souches, différentes lactones sont produites et leur reconsommation peut être nettement ralentie. Cette étude montre qu'on peut maîtriser la β-oxydation en modifiant le matériel génétique des souches et qu'on peut ainsi améliorer les productions existantes mais aussi produire de nouvelles molécules d'intérêt. [less ▲]

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See detailModification of Chloroplast Gene Transmission in Somatic Fusion Products and Vegetative Zygotes of Chlamydomonas Reinhardi by 5-Fluorodeoxyuridine
Matagne, René-Fernand ULg; Hermesse, Marie-Paule

in Genetics (1981), 99(3-4), 371-381

Sexual crosses and somatic fusions were performed between complementing wall-less arg(-) mutant strains bearing chloroplast markers for resistance to antibiotics. The mode of chloroplast allele ... [more ▼]

Sexual crosses and somatic fusions were performed between complementing wall-less arg(-) mutant strains bearing chloroplast markers for resistance to antibiotics. The mode of chloroplast allele transmission was investigated in the diploid colonies developed from both vegetative zygotes and fusion products. Before mating or fusion, one or both of the parental strains were grown for 4 or 8 days on agar containing 5-fluorodeoxyuridine (FUdR, 0.1 to 1.0 mm), which selectively reduces the amount of chloroplast DNA in Chlamydomonas. When one parent was pregrown on FUdR, the frequency of vegetative zygotes transmitting chloroplast alleles of both parents (biparental or BP zygotes) decreased, the reduction being more drastic when the mt(-) parent was treated. Transmission was mainly uniparental maternal (UPm) or paternal (UPp) depending on whether the mt(-) or the mt(+) parent was pregrown for 8 days in the presence of 1.0 mm FUdR. Treatment of both parents led to a strong maternal transmission. In the experiments involving somatic fusion between parent 1 and parent 2 (same or opposite mt), the ratio UP(1)/UP(2), which was approximately equal to 1 in the control, decreased or increased according to whether the cells of parent 1 or 2 were pregrown on FUdR. In parallel, the frequency of BP fusion products always decreased. When both parental strains were treated with FUdR, the frequency of BP fusion products also decreased and the ratio UP(1)/UP(2) was roughly equal to 1. The effect of FUdR can be interpreted in terms of reduction of the input frequencies of parental chloroplast genomes at the time of gametic or somatic cell fusion, the bias in favor of the maternal parent being operational only in sexual crosses. [less ▲]

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See detailA modification of convex approximation methods for structural optimization
Zhang, Wei-Hong; Fleury, Claude ULg

in Computers & Structures (1997), 64(1-4), 89-95

The most popular convex approximation methods used today in structural optimization are discussed in this paper: the convex linearization method (CONLIN), the method of the moving asymptotes (MMA) and the ... [more ▼]

The most popular convex approximation methods used today in structural optimization are discussed in this paper: the convex linearization method (CONLIN), the method of the moving asymptotes (MMA) and the sequential quadratic programming method (SQP). Modifications are made to enhance the reliability of the CONLIN method. In addition, a generalized MMA (GMMA) is established. However, in view of practical difficulties of evaluating second-order derivatives, a fitting scheme is proposed in this work to adjust the convexity of the approximation based on the available function value at the preceding design iteration. Numerical results show that this simple scheme is efficient in our applications. [less ▲]

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See detailModification of diet in renal disease versus chronic kidney disease epidemiology collaboration equation to estimate glomerular filtration rate in obese patients
BOUQUEGNEAU, Antoine ULg; Vidal-Petiot, Emanuelle; Vrtovsnik, François et al

in Nephrology Dialysis Transplantation (2013), 28(4), 122-130

Background Obesity is a recognized risk factor for both the development and progression of chronic kidney disease (CKD). Accurate estimation of glomerular filtration rate (GFR) is thus important in these ... [more ▼]

Background Obesity is a recognized risk factor for both the development and progression of chronic kidney disease (CKD). Accurate estimation of glomerular filtration rate (GFR) is thus important in these patients. We tested the performances of two creatinine-based GFR estimates, the Modification of Diet in Renal Disease (MDRD) and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, in an obese population. Methods Patients with body mass index (BMI) > 30 kg/m2 were included. The reference method for measured GFR (mGFR) was 51Cr-EDTA (single-injection method, two blood samples at 120 and 240 min). Both indexed and non-indexed results were considered. Serum creatinine was measured using the IDMS-traceable compensated Jaffe method. Mean bias (eGFR–mGFR), precision (SD around the bias) and accuracy within 30% (percentage of estimations within 30% of mGFR) were calculated for both equations. Results The population included 366 patients (185 women) from two different areas. Mean age was 55 ± 14 years, and mean BMI was 36 ± 7 kg/m2. Mean mGFR was 56 ± 26 mL/min/1.73 m2 (71 ± 35 mL/min without indexation). In the total population, mean bias was +1.9 ± 14.3 and +4.6 ± 14.7 mL/min/1.73 m2 (P < 0.05), and accuracy 30% was 80 and 76% for the MDRD and CKD-EPI equations (P < 0.05), respectively. In patients with mGFR > 60 mL/min/1.73 m2, mean bias was +4.6 ± 18.4 and +9.3 ± 17.2 mL/min/1.73 m2 (P < 0.05), and accuracy 30% was 81 and 79% (NS) for the MDRD and CKD-EPI equations, respectively. Conclusions The CKD-EPI equation did not outperform the MDRD study equation in this population of obese patients [less ▲]

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See detailModification of hormonal secretion in macroprolactinoma on treatment
VROONEN, Laurent ULg; Rostomyan, Liliya ULg; Potorac, Iulia ULg et al

in 23rd meeting of the Belgian Endocrine Society - Abstract book (2013, October 19)

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See detailModification of immunoreactive EGF receptor after acute tubular necrosis induced by tobramycin or cisplatin
Leonard, I.; Zanen, J.; Nonclercq, D. et al

in Renal Failure (1994), 16(5), 583-608

Acute tubular necrosis induced by aminoglycoside antibiotics and various other nephrotoxins is followed by a regenerative process which leads to the restoration of damaged tubules. Several lines of ... [more ▼]

Acute tubular necrosis induced by aminoglycoside antibiotics and various other nephrotoxins is followed by a regenerative process which leads to the restoration of damaged tubules. Several lines of evidence indicate that tubular regeneration is mediated by polypeptide growth factors such as epidermal growth factor (EGF). Previous studies devoted to cisplatin nephrotoxicity have shown that this agent causes tubular cystic degeneration possibly related to an impairment of renal tissue repair. Thus, we examined on a comparative basis the time course of the regenerative response subsequent to tubular damage induced by tobramycin or cisplatin, particular attention being paid to renal EGF and its receptor. Female Sprague-Dawley rats (160-180 g body weight) were treated during 4 consecutive days with daily doses of 200 mg/kg tobramycin i.p. (BID) or 2 mg/kg cisplatin (once a day). Sham-treated rats were given 0.9% NaCl i.p. following the same protocol. Groups of experimental animals (n = 5-10) were terminated at increasing time intervals (1, 4, 7, 14, 21, 60 days) after cessation of treatment. One hour prior to sacrifice, each individual received i.p. 200 mg/kg 5-bromo-2'-deoxyuridine (BrdU) for the immunohistochemical demonstration of cell proliferation. Blood was collected at the time of sacrifice in order to assess glomerular filtration rate by measuring serum creatinine and BUN levels. Kidneys were analyzed with respect to total EGF determined by RIA in renal tissue homogenates, and soluble EGF was assayed in extracts prepared by centrifugation. Renal tissue was processed for the immunohistochemical detection of S-phase cells, of EGF, of EGF receptors, and of the intermediate filament vimentin, the latter being used as a marker of epithelium dedifferentiation. In absence of nephrotoxic alterations, EGF was immunolocalized in distal tubules, whereas EGF receptor immunostaining was seen in proximal tubules cells. Vimentin immunostaining was confined to glomeruli and blood vessels. Tobramycin and cisplatin caused acute tubular necrosis in proximal convoluted tubules and proximal straight tubules, respectively. Tissue damage was accompanied by renal dysfunction reflected by an elevation of serum creatinine and BUN levels. Tubular necrosis was followed by a proliferative response indicative of tubular regeneration. Regenerative hyperplasia was associated with a reduction of total immunoreactive EGF due to a decrease of tissue-bound proEGF. Tubules undergoing regenerative repair were characterized by a disappearance of EGF receptors and the presence of immunoreactive vimentin. In tobramycin-treated rats, renal dysfunction lasted for 4-7 days and was fully reversible, as indicated by the return of serum markers to normal values. [less ▲]

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See detailModification of the interfacial properties of whey by enzymatic hydrolysis of the residual fat.
Blecker, Christophe ULg; Cerne, V.; Paquot, Michel ULg et al

in Lorient, D.; Dickinson, E. (Eds.) Food Macromolecules and Colloids. (1995)

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See detailModification of the polycarbonate/poly(vinylidene Fluoride) interface by poly(methyl methacrylate). Effect on the interfacial adhesion and interfacial tension
Moussaif, Noureddin; Jérôme, Robert ULg

in Macromolecular Symposia (1999), 139

Polycarbonate (PC) and poly(vinylidene fluoride) (PVDF) are two immiscible polymers which form two-phase blends with weak interfacial adhesion and high interfacial tension This situation may be changed by ... [more ▼]

Polycarbonate (PC) and poly(vinylidene fluoride) (PVDF) are two immiscible polymers which form two-phase blends with weak interfacial adhesion and high interfacial tension This situation may be changed by the addition of poly(methyl methacrylate) (PMMA), which concentrates preferably in the PVDF-rich phase, but also at the PVDF/PC interface. The interfacial activity of PMMA was estimated by the measurement of the interfacial adhesion and interfacial tension in relation to the PMMA content in the PVDF/PC blends. The interfacial adhesion between PC and homogeneous PVDF/PMMA blends of various compositions was measured by the dual cantilever beam technique The imbedded fiber retraction method was used for the measurement of the interfacial tension. A very beneficial effect was observed when PVDF was premixed with PMMA amounts increasing up to ca 35 wt-%., Beyond that content, the improvement tends to level off. [less ▲]

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See detailModification of the Selected Method for the Determination of Serum Iron. Substitution of Bathophenanthroline by Ferene S
Charlier, Corinne ULg; Plomteux, Guy ULg; Vernet, M. et al

in Annales de Biologie Clinique (1992), 50(3), 191-202

The previously selected method (1977) for the measurement of iron in human serum has been modified by the working group on Iron and Iron-Transport Proteins (Societe Francaise de Biologie Clinique). Ferene ... [more ▼]

The previously selected method (1977) for the measurement of iron in human serum has been modified by the working group on Iron and Iron-Transport Proteins (Societe Francaise de Biologie Clinique). Ferene S is used as the chromogen, it is more sensitive and cheaper than bathophenanthroline. The sample size has been reduced from 2 to 0.5 ml. No interference could be shown with high concentrations of bilirubin, copper or hemoglobin. [less ▲]

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See detailModification of the thermoresistance to spray-drying of a cold-adapted subtilisin by genetic engineering
Bare, G.; Diakiese, A.; Zgoulli, S. et al

Poster (1998, May 08)

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See detailModification of the Thermoresistance to Spray-Drying of a Cold-Adapted Subtilisin by Genetic Engineering
Bare, G.; Diakiese, A.; Zgoulli, S. et al

in Applied Biochemistry and Biotechnology (1999), 77-79(Spring), 857-65

The thermoresistance of a cold-adapted subtilisin dried by spray-drying was studied. Proteolytic activity of this enzyme was measured before and after spray-drying. Without chemical additives, spray ... [more ▼]

The thermoresistance of a cold-adapted subtilisin dried by spray-drying was studied. Proteolytic activity of this enzyme was measured before and after spray-drying. Without chemical additives, spray-drying yields ranged from 2-13%. The use of arabic gum and lactose in the composition of the enzyme solutions allowed the strengthening of the enzyme structures and increased water mobility in the product. Increase of water mobility led to a shorter residence time of the product in the spray-drier and a net yield increase was obtained (yield higher than 50%). The effect of two selective mutations on the thermoresistance to spray-drying of the cold-adapted subtilisin was also investigated. Mutation T85D (introduction of an additional link with an ion Ca2+ necessary for enzyme activity, by substitution of Asp for Thr 85) had no effect on the thermoresistance of the subtilisin to spray-drying. Mutation H121W (introduction of an additional aromatic link by substitution of Trp for His 121) reduced the drying yield from 66% (not modified subtilisin) to 52%. This higher thermosensitivity could be explained by an increase of the hygroscopic character of the modified subtilisin (mutation H121W). [less ▲]

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See detailModification of the trapped field in bulk HTS as a result of the drilling of a pattern of artificial holes
Lousberg, G. P.; Fagnard, Jean-François ULg; Ausloos, Marcel ULg et al

in Journal of Physics: Conference Series (2010), 234

The trapped magnetic field is examined in bulk high-temperature superconductors that are artificially drilled along their c-axis. The influence of the hole pattern on the magnetization is studied and ... [more ▼]

The trapped magnetic field is examined in bulk high-temperature superconductors that are artificially drilled along their c-axis. The influence of the hole pattern on the magnetization is studied and compared by means of numerical models and Hall probe mapping techniques. To this aim, we consider two bulk YBCO samples with a rectangular cross-section that are drilled each by six holes arranged either on a rectangular lattice (sample I) or on a centered rectangular lattice (sample II). For the numerical analysis, three different models are considered for calculating the trapped flux: (i), a two-dimensional (2D) Bean model neglecting demagnetizing effects and flux creep, (ii), a 2D finite-element model neglecting demagnetizing effects but incorporating magnetic relaxation in the form of an E – J power law, and, (iii), a 3D finite element analysis that takes into account both the finite height of the sample and flux creep effects. For the experimental analysis, the trapped magnetic flux density is measured above the sample surface by Hall probe mapping performed before and after the drilling process. The maximum trapped flux density in the drilled samples is found to be smaller than that in the plain samples. The smallest magnetization drop is found for sample II, with the centered rectangular lattice. This result is confirmed by the numerical models. In each sample, the relative drops that are calculated independently with the three different models are in good agreement. As observed experimentally, the magnetization drop calculated in the sample II is the smallest one and its relative value is comparable to the measured one. By contrast, the measured magnetization drop in sample (1) is much larger than that predicted by the simulations, most likely because of a change of the microstructure during the drilling process. [less ▲]

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See detailModification ultrastructurale du nucléole au cours de l'ovogenèse chez un poisson téléostéen ovipare Barbus barbus.
Thiry, M.; Lepoint, A.; Poncin, Pascal ULg et al

in Cahiers d'Ethologie Appliquée (1993), 13(2), 247-248

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See detailModifications cognitives liées au vieillissement normal
Collette, Fabienne ULg

Scientific conference (2008, May 27)

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See detailModifications de l’activité cérébrale et troubles mnésiques dans le vieillissement
Collette, Fabienne ULg

Scientific conference (2010, November)

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