References of "Elmoualij, Benaïssa"
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See detailPeculiar hydrophobic properties of the 67-78 fragment of α-synuclein are responsible for membrane destabilization and neurotoxicity
Crowet, Jean-Marc ULg; Lins, Laurence ULg; Dupiereux-Fettweis, Ingrid ULg et al

Poster (2007, March 14)

α-synuclein is a 140 residue protein linked to Parkinson’s disease. Intraneural inclusions called Lewy bodies and Lewy neurites are mainly composed of α-synuclein aggregated in amyloid fibrils. Few years ... [more ▼]

α-synuclein is a 140 residue protein linked to Parkinson’s disease. Intraneural inclusions called Lewy bodies and Lewy neurites are mainly composed of α-synuclein aggregated in amyloid fibrils. Few years ago, tilted peptides have been detected in two other amyloidogenic proteins : the amyloid β peptide involved in Alzheimer’s disease, and the PrP protein linked to Creuztfeldt-Jakob’s disease. Tilted peptides are short protein fragments that adopt an oblique orientation when inserted into biological membranes. Tilted peptides are able to destabilize membranes. In this study, we predicted by sequence analysis and molecular modelling that the 67-78 fragment of α-synuclein is a tilted peptide. Like most of them, the α-syn 67-78 peptide is able to induce lipid mixing and leakage of unilamellar liposomes. A mutant designed by molecular modelling to decrease the destabilizing properties of the peptide was shown to be significantly less fusogenic. The neuronal toxicity was studied using human neuroblastoma cells and we demonstrated that the α-syn 67-78 peptide induces neurotoxicity. In conclusion, we have identified a tilted peptide in α-synuclein which could be involved in the toxicity induced during amyloidogenesis of α-synuclein. [less ▲]

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See detailPeculiar hydrophobic properties of the 67-78 fragment of α-synuclein are responsible for membrane destabilization and neurotoxicity
Crowet, Jean-Marc ULg; Lins, Laurence ULg; Dupiereux-Fettweis, Ingrid ULg et al

Poster (2006, December 18)

α-synuclein is a 140 residue protein linked to Parkinson’s disease. Intraneural inclusions called Lewy bodies and Lewy neurites are mainly composed of α-synuclein aggregated in amyloid fibrils. Few years ... [more ▼]

α-synuclein is a 140 residue protein linked to Parkinson’s disease. Intraneural inclusions called Lewy bodies and Lewy neurites are mainly composed of α-synuclein aggregated in amyloid fibrils. Few years ago, tilted peptides have been detected in two other amyloidogenic proteins : the amyloid β peptide involved in Alzheimer’s disease, and the PrP protein linked to Creuztfeldt-Jakob’s disease. Tilted peptides are short protein fragments that adopt an oblique orientation when inserted into biological membranes. Tilted peptides are able to destabilize membranes. In this study, we predicted by sequence analysis and molecular modelling that the 67-78 fragment of α-synuclein is a tilted peptide. Like most of them, the α-syn 67-78 peptide is able to induce lipid mixing and leakage of unilamellar liposomes. A mutant designed by molecular modelling to decrease the destabilizing properties of the peptide was shown to be significantly less fusogenic. The neuronal toxicity was studied using human neuroblastoma cells and we demonstrated that the α-syn 67-78 peptide induces neurotoxicity. In conclusion, we have identified a tilted peptide in α-synuclein which could be involved in the toxicity induced during amyloidogenesis of α-synuclein. [less ▲]

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See detailTRANSMISSION ET RÉSISTANCE DES PRIONS : LA PRATIQUE DE LA MÉDECINE DENTAIRE EN SERA T-ELLEAFFECTÉE ?
Elmoualij, Benaïssa ULg; Heinen, Ernst ULg; Zorzi, Willy ULg et al

in Journal de l'Ordre des Dentistes du Québec (2006), 43(9), 461-467

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See detailAdvances in immunoproteomics for serological characterization of microbial antigens
Falisse-Poirier, Nandini; Ruelle, Virginie ULg; Elmoualij, Benaïssa ULg et al

in Journal of Microbiological Methods (2006), 67(3), 593-596

We propose a multi-dimensional strategy, associating immunodetection to a protein fractionating two-dimensional liquid chromatography tool, for serological characterization of microbial antigens. The ... [more ▼]

We propose a multi-dimensional strategy, associating immunodetection to a protein fractionating two-dimensional liquid chromatography tool, for serological characterization of microbial antigens. The originality of such immunoproteomic approaches resides in their application in large-scale studies for rapid serotyping of micro-organisms, evaluation of immunomes and could be proposed in the development and monitoring of vaccines. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailImmunoquantitative real-time PCR for detection and quantification of Staphylococcus aureus enterotoxin B in foods
Rajkovic, A.; Elmoualij, Benaïssa ULg; Uyttendaele, M. et al

in Applied and Environmental Microbiology (2006), 72(10), 6593-6599

A real-time immunoquantitative PCR (iqPCR) method for detection of Staphylococcus aureus enterotoxin B (SEB) was developed and evaluated using both pure cultures and foods. The assay consisted of ... [more ▼]

A real-time immunoquantitative PCR (iqPCR) method for detection of Staphylococcus aureus enterotoxin B (SEB) was developed and evaluated using both pure cultures and foods. The assay consisted of immunocapture of SEB and real-time PCR amplification of the DNA probe linked to the detection antibody. iqPCR was compared to an in-house enzyme-linked immunosorbent assay (ELISA) using the same couple of capture-detection antibodies and to commercial kits for detection of S. aureus enterotoxins (SE). The iqPCR was approximately 1,000 times more sensitive (< 10 pg ml(-1)) than the in-house ELISA and had a dynamic range of approximately 10 pg ml(-1) to approximately 30,000 pg ml(-1). iqPCR was not inhibited by any of the foods tested and was able to detect SEB present in these foods. No cross-reactivity with SE other than SEB was observed. Application of iqPCR for detection of SEB in cultures of S. aureus revealed the onset of SEB production after 4 It of incubation at 22, 37, and 42 degrees C, which was in the first half of the exponential growth phase. The total amounts of SEB produced by the two strains tested were larger at 42 degrees C than at 37 degrees C and were strain dependent. [less ▲]

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See detailStudy on the toxic mechanism of prion protein peptide 106-126 in neuronal and non neuronal cells
Dupiereux-Fettweis, Ingrid ULg; Zorzi, Willy ULg; Rachidi, W. et al

in Journal of Neuroscience Research (2006), 84(3), 637-646

A synthetic peptide corresponding to the 106-126 amyloidogenic region of the cellular human prion protein (PrPc) is useful for in vitro study of prion-induced neuronal cell death. The aim of the present ... [more ▼]

A synthetic peptide corresponding to the 106-126 amyloidogenic region of the cellular human prion protein (PrPc) is useful for in vitro study of prion-induced neuronal cell death. The aim of the present work was to examine the implication of the cellular prion protein in the toxicity mechanism induced by PrP 106-126. The effect of PrP 106-126 was investigated both on human neuroblastoma SH-SY5Y cells and on SH-SY5Y over-expressing murine cellular prions (wtPrP). We show by metabolic assay tests and ATP assays that PrPc expression does not modulate the toxicity of the prion peptide. Moreover, we investigated the effect of this peptide on an established non neuronal model, rabbit kidney epithelial A74 cells that express a doxycycline-inducible murine PrPc gene. We show for the first time that the prion peptide 106-126 does not exert any toxic effect on this cell line in the presence or absence of doxycycline. Our results show that the PrP 106-126-induced cell alteration is independent of PrPc expression. Rather, it seems to act via an interaction with lipidic components of the plasma membrane as strengthened by our results showing the differential susceptibility of neuronal and non neuronal cell lines that significantly differ by their membrane fatty acid composition. (c) 2006 Wiley-Liss, Inc. [less ▲]

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See detailDevelopment of a serum-free co-culture of human intestinal epithelium cell-lines (Caco-2/HT29-5M21)
Nollevaux, Géraldine; Deville, Christelle ULg; Elmoualij, Benaïssa ULg et al

in BMC Cell Biology (2006), 7

Background: The absorptive and goblet cells are the main cellular types encountered in the intestine epithelium. The cell lineage Caco-2 is a model commonly used to reproduce the features of the bowel ... [more ▼]

Background: The absorptive and goblet cells are the main cellular types encountered in the intestine epithelium. The cell lineage Caco-2 is a model commonly used to reproduce the features of the bowel epithelium. However, there is a strong debate regarding the value of Caco-2 cell culture to mimick in vivo situation. Indeed, some authors report in Caco-2 a low paracellular permeability and an ease of access of highly diffusible small molecules to the microvilli, due to an almost complete lack of mucus. The HT29-5M21 intestinal cell lineage is a mucin-secreting cellular population. A co-culture system carried out in a serum-free medium and comprising both Caco-2 and HT29-5M21 cells was developed. The systematic use of a co-culture system requires the characterization of the monolayer under a given experimental procedure. Results: In this study, we investigated the activity and localization of the alkaline phosphatase and the expression of IAP and MUC5AC genes to determine a correlation between these markers and the cellular composition of a differentiated monolayer obtained from a mixture of Caco-2 and HT29-5M21 cells. We observed that the culture conditions used ( serum-free medium) did not change the phenotype of each cell type, and produced a reproducible model. The alkaline phosphatase expression characterizing Caco-2 cells was influenced by the presence of HT29-5M21 cells. Conclusion: The culture formed by 75% Caco-2 and 25% HT29-5M21 produce a monolayer containing the two main cell types of human intestinal epithelium and characterized by a reduced permeability to macromolecules. [less ▲]

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See detailImmunoquantitative PCR for prion protein detection in sporadic Creutzfeldt-Jakob disease.
Gofflot, Stéphanie ULg; Deprez, Manuel ULg; Elmoualij, Benaïssa ULg et al

in Clinical Chemistry (2005), 51(9), 1605-11

BACKGROUND: The most common human prion disorder is Creutzfeldt-Jakob disease (CJD); it includes sporadic, familial, iatrogenic, and variant subtypes. Diagnostic tests aim at detection with the highest ... [more ▼]

BACKGROUND: The most common human prion disorder is Creutzfeldt-Jakob disease (CJD); it includes sporadic, familial, iatrogenic, and variant subtypes. Diagnostic tests aim at detection with the highest specificity of very small deposits of abnormal prion protein (PrP). METHODS: We used immunoquantitative PCR (iqPCR) to detect proteinase K-resistant PrP (PrPRes) in tissue from the middle frontal gyrus of 7 patients with sporadic CJD and 7 non-CJD cases. We compared iqPCR with routine optimized ELISA, Western blotting, and immunohistochemical analyses. RESULTS: The 4 methods showed similar 100% sensitivity and specificity for the diagnosis of CJD. Along with high specificity, however, iqPCR had a threshold for PrP(Res) detection at least 10-fold lower than that of the classic ELISA. CONCLUSIONS: iqPCR is a new method for PrPRes detection that combines 100% specificity with a detection threshold at least 10-fold lower than classic techniques. This method may improve the detection of minute PrPRes deposits in tissues and body fluids and thus be useful for diagnostic and sterilization applications. [less ▲]

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See detailInteraction of the 106-126 prion peptide with lipid membranes and potential implication for neurotoxicity.
Dupiereux-Fettweis, Ingrid ULg; Zorzi, Willy ULg; Lins, Laurence ULg et al

in Biochemical and Biophysical Research Communications (2005), 331(4), 894-901

Prion diseases are fatal neurodegenerative disorders characterized by the accumulation in the brain of an abnormally misfolded, protease-resistant, and beta-sheet rich pathogenic isoform (PrP(SC)) of the ... [more ▼]

Prion diseases are fatal neurodegenerative disorders characterized by the accumulation in the brain of an abnormally misfolded, protease-resistant, and beta-sheet rich pathogenic isoform (PrP(SC)) of the cellular prion protein (PrP(C)). In the present work, we were interested to study the mode of prion protein interaction with the membrane using the 106-126 peptide and small unilamellar lipid vesicles as model. As previously demonstrated, we showed by MTS assay that PrP 106-126 induces alterations in the human neuroblastoma SH-SY5Y cell line. We demonstrated for the first time by lipid-mixing assay and by the liposome vesicle leakage test that PrP 106-126, a non-tilted peptide, induces liposome fusion thus a potential cell membrane destabilization, as supported by membrane integrity assay (LDH). By circular dichroism (CD) analysis we showed that the fusogenic property of PrP 106-126 in the presence of liposome is associated with a predominantly beta-sheet structure. These data suggest that the fusogenic property associated with a predominant beta-sheet structure exhibited by the prion peptides contributes to the neurotoxicity of these peptides by destabilizing cellular membranes. The latter might be attached at the membrane surface in a parallel orientation as shown by molecular modeling. [less ▲]

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See detailImmuno-quantitative polymerase chain reaction for detection and quantitation of prion protein
Gofflot, Stéphanie ULg; Elmoualij, Benaïssa ULg; Zorzi, Danièle ULg et al

in Journal of Immunoassay & Immunochemistry (2004), 25(3), 241-258

Immuno-polymerase chain reaction (PCR) is an extremely sensitive detection method, combining the specificity of antibody detection and the sensitivity of PCR. We have developed an immuno-quantitative PCR ... [more ▼]

Immuno-polymerase chain reaction (PCR) is an extremely sensitive detection method, combining the specificity of antibody detection and the sensitivity of PCR. We have developed an immuno-quantitative PCR (iqPCR), exploiting real-time PCR technology, in order to improve this immuno-detection method and make it quantitative. To illustrate the advantages of iqPCR, we have compared it with a conventional enzyme linked immuno sorbent assay (ELISA) technique in experiments aimed at detecting the cellular and the resistant form of prion protein in bovine brain extract. The iqPCR technique proved to be more sensitive than ELISA, so it could be a technique of choice for the diagnosis of infected animals both at an ante mortem and post-mortem stage. [less ▲]

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See detailHuman recombinant thiamine triphosphatase: purification, secondary structure and catalytic properties
Lakaye, Bernard ULg; Makarchikov, Alexander F; Wins, Pierre et al

in International Journal of Biochemistry & Cell Biology (2004), 36(7), 1348-1364

Thiamine triphosphate (ThTP) is found in most living organisms and it may act as a phosphate donor for protein phosphorylation. We have recently cloned the cDNA coding for a highly specific mammalian 25 ... [more ▼]

Thiamine triphosphate (ThTP) is found in most living organisms and it may act as a phosphate donor for protein phosphorylation. We have recently cloned the cDNA coding for a highly specific mammalian 25 kDa thiamine triphosphatase (ThTPase; EC 3.6.1.28). As the enzyme has a high catalytic efficiency and no sequence homology with known phosphohydrolases, it was worth investigating its structure and catalytic properties. For this purpose, we expressed the untagged recombinant human ThTPase (hThTPase) in E. coli, produced the protein on a large scale and purified it to homogeneity. Its kinetic properties were similar to those of the genuine human enzyme, indicating that the recombinant hThTPase is completely functional. Mg2+ ions were required for activity and Ca2+ inhibited the enzyme by competition with Mg2+. With ATP as substrate, the catalytic efficiency was 10(-4)-fold lower than with ThTP, confirming the nearly absolute specificity of the 25 kDa ThTPase for ThTP. The activity was maximum at pH 8.5 and very low at pH 6.0. Zn2+ ions were inhibitory at micromolar concentrations at pH 8.0 but activated at pH 6.0. Kinetic analysis suggests an activator site for Mg2+ and a separate regulatory site for Zn2+. The effects of group-specific reagents such as Woodward's reagent K and diethylpyrocarbonate suggest that at least one carboxyl group in the active site is essential for catalysis, while a positively charged amino group may be involved in substrate binding. The secondary structure of the enzyme, as determined by Fourier-transform infrared spectroscopy, was predominantly beta-sheet and alpha-helix. [less ▲]

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See detailTransport of arginine and ornithine into isolated mitochondria of Saccharomyces cerevisiae.
Soetens, Oriane; Crabeel, Marjolaine; Elmoualij, Benaïssa ULg et al

in European Journal of Biochemistry (1998), 258(2), 702-9

In this work we have characterised the transport of L-arginine and L-ornithine into mitochondria isolated from a wild-type Saccharomyces cerevisiae strain and an isogenic arg11 knock-out mutant. The Arg11 ... [more ▼]

In this work we have characterised the transport of L-arginine and L-ornithine into mitochondria isolated from a wild-type Saccharomyces cerevisiae strain and an isogenic arg11 knock-out mutant. The Arg11 protein (Arg11p) is a mitochondrial carrier required for arginine biosynthesis [Crabeel, M., Soetens, O., De Rijcke, M., Pratiwi, R. & Pankiewicz, R. (1996) J. Biol. Chem. 271, 25011-25019]. Reconstitution experiments have confirmed that it is an L-ornithine carrier also transporting L-arginine and L-lysine by order of decreasing affinity, but not L-histidine [Palmieri, L., De Marco, V., Iacobazzi, V., Palmieri, F., Runswick, M. & Walker, J. (1997) FEBS Lett. 410, 447-451]. Evidence is presented here that the mitochondrial inner membrane contains an L-arginine and L-ornithine transporting system distinct from Arg11p, in keeping with the arginine leaky phenotype of arg11 knock-out mutants. The newly characterised carrier, which we propose to name Bac1p (basic amino acid carrier), behaves as an antiporter catalysing the electroneutral exchange of the basic amino acids L-arginine, L-lysine, L-ornithine and L-histidine and displays the highest affinity for L-arginine (Km of 30 microM). L-Arginine uptake has a pH optimum in the range of 7.5-9 and is inhibited by several sulphydryl reagents, by pyridoxal 5'-phosphate and by cations [less ▲]

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See detailPhylogenetic classification of the mitochondrial carrier family of Saccharomyces cerevisiae.
Elmoualij, Benaïssa ULg; Duyckaerts, Claire ULg; Brasseur, Josette ULg et al

in Yeast (Chichester, England) (1997), 13(6), 573-581

The screening of the open reading frames identified in the whole yeast genome has allowed us to discover 34 proteins belonging to the mitochondrial carrier family. By phylogenetic study, they can be ... [more ▼]

The screening of the open reading frames identified in the whole yeast genome has allowed us to discover 34 proteins belonging to the mitochondrial carrier family. By phylogenetic study, they can be divided into 27 subfamilies including ADP/ATP, phosphate and citrate carriers, putative oxoglutarate and GDC carriers and 22 new subfamilies. Topology predictions using the 'positive inside rule' approach have shown that the yeast carriers are similarly oriented with both extremities exposed to the cytosol. In each subfamily, a strict conservation of the charged residues in the six transmembrane alpha-helices is observed, suggesting a functional role for these residues and the existence of 27 functionally distinct carriers. [less ▲]

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See detailLocalisation mitochondriale du produit du gène levurien RIM2
Elmoualij, Benaïssa ULg

Master's dissertation (1994)

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See detaillocalisation transmembranaire du transporteur mitochondrial présumé RIM2 de Saccharomyces Cerevisiae
Elmoualij, Benaïssa ULg

Master of advanced studies dissertation (1994)

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