References of "Vreuls, Christelle"
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See detailInorganic-binding peptides as tools for surface quality control
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Genin, Alexis ULg et al

in Journal of Inorganic Biochemistry (2010)

This paper highlights an innovative application of inorganic-binding peptides as quality control tools for detecting defects on inorganic surfaces of any shape. The approach involves attaching a ... [more ▼]

This paper highlights an innovative application of inorganic-binding peptides as quality control tools for detecting defects on inorganic surfaces of any shape. The approach involves attaching a fluorescent label to an inorganic-binding peptide and exploiting the peptide's high binding specificity to detect, by simple fluorescence microscopy, chemical composition defects of microm size and crystallographic state defects. Proof of concept was demonstrated by monitoring binding of a previously isolated ZnO-binding peptide to galvanized steel substrates. The approach was further validated for TiO(2) coatings and stainless steel, with two new, specific inorganic-binding peptides isolated by phage display. [less ▲]

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See detailPrevention of bacterial biofilms by covalent immobilization of peptides onto plasma polymer functionalized substrates
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Thierry, Benjamin et al

in Journal of Materials Chemistry (2010), 20

In this study, robust antibacterial coatings were created on stainless steel through the covalent grafting of antibacterial peptides onto an organic-polymeric interlayer deposited by RF-glow discharge ... [more ▼]

In this study, robust antibacterial coatings were created on stainless steel through the covalent grafting of antibacterial peptides onto an organic-polymeric interlayer deposited by RF-glow discharge plasma. X-Ray photoelectron spectroscopy was used to characterize and optimize the two steps of the coating process. The biocidal activity of these surfaces was demonstrated against both Gram+ and Gram- bacteria using ISO tests. 3 to 6 log10 reductions of both Gram+ and Gram- bacterial strains were obtained compared to uncoated stainless steel and depending on the particular antibacterial peptide immobilized. Importantly the antibacterial surfaces were resistant to several cleaning conditions. The latter is significant as the stability of such antibacterial surfaces in close to real life conditions is a major concern and leaching, de-lamination, rearrangement and ageing of the coating can lead to insufficient long term biofilm resistance of the surface. [less ▲]

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See detailBiomolecules in multilayer film for antimicrobial and easy-cleaning stainless steel surface applications
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Garitte, Geoffrey ULg et al

in Biofouling (2010), 26(6), 645-656

Microorganisms are able to attach to, grow on, and ultimately form biofilms on a large variety of surfaces, such as industrial equipment, food contact surfaces, medical implants, prostheses and operating ... [more ▼]

Microorganisms are able to attach to, grow on, and ultimately form biofilms on a large variety of surfaces, such as industrial equipment, food contact surfaces, medical implants, prostheses and operating rooms. Once organized into biofilms, bacteria are difficult to remove and kill, which increases the risk of cross-contamination and infection. One way to address the problem may thus be to develop antibacterial, anti-adhesion, ‘easy cleaning’ surfaces. In this study, stainless steel (SS) surfaces with antibacterial properties were created by embedding several antimicrobial peptides in a multilayer film architecture. The biocidal effect of these surfaces was demonstrated against both Gram-positive and Gram-negative bacteria according to two ISO tests. Also, coating SS surfaces with either mucin or heparin led to a reduction of <i>S. epidermidis</i> adhesion of almost 95% <i>vs</i> the bare substratum. Finally, by combining both antibacterial and anti-adhesion biomolecules in the same multilayer film, SS surfaces with better cleanability were produced. This surface coating property may help to delay the buildup of a dead bacterial layer which is known to progressively reduce exposure of the coating, leading to an undesirable decrease in the antibacterial effect of the surface. [less ▲]

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See detailMultifunctional coatings
Van de Weerdt, Cécile ULg; Detrembleur, Christophe ULg; Charlot, Aurelia et al

Patent (2009)

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See detailNanocoatings of inorganic surfaces by the layer by layer (LbL) technology
Faure, Emilie ULg; Zocchi, Germaine ULg; Lenoir, Sandrine et al

Poster (2009, April 02)

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See detailNanocoatings of steel surfaces by molecular biomimetic
Vreuls, Christelle ULg; Charlot, Aurelia; Farina, Fabrice ULg et al

Scientific conference (2007, June 01)

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See detailGuanidinium chloride denaturation of the dimeric Bacillus licheniformis Blal repressor highlights an independent domain unfolding pathway
Vreuls, Christelle ULg; Filée, Patrice ULg; Van Melckebeke, H. et al

in Biochemical Journal (2004), 384(Pt 1), 179-190

The Bacillus licheniformis 74911 BlaI repressor is a prokaryotic regulator that, in the absence of a P-lactam antibiotic, prevents the transcription of the blaP gene, which encodes the BlaP beta-lactamase ... [more ▼]

The Bacillus licheniformis 74911 BlaI repressor is a prokaryotic regulator that, in the absence of a P-lactam antibiotic, prevents the transcription of the blaP gene, which encodes the BlaP beta-lactamase. The BlaI repressor is composed of two structural domains. The 82-residue NTD (N-terminal domain) is a DNA-binding domain, and the CTD (C-terminal domain) containing the next 46 residues is a dimerization domain. Recent studies have shown the existence of the monomeric, dimeric and tetrameric forms of BlaI in solution. In the present study, we analyse the equilibrium unfolding of BlaI in the presence of GdmCl (guanidinium chloride) using different techniques: intrinsic and ANS (8-anilinonaphthalene-1-sulphonic acid) fluorescence, far- and near-UV CD spectroscopy, cross-linking, analytical ultracentrifugation, size exclusion chromatography and NMR spectroscopy. In addition, the intact NTD and CTD were purified after proteolysis of BlaI by papain, and their unfolding by GdmCl was also studied. GdmCl-induced equilibrium unfolding was shown to be fully reversible for BlaI and for the two isolated fragments. The results demonstrate that the NTD and CTD of BlaI fold/unfold independently in a four-step process, with no significant cooperative interactions between them. During the first step, the unfolding of the Blal CTD occurs, followed in the second step by the formation of an 'ANS-bound' intermediate state. Crosslinking and analytical ultracentrifugation experiments suggest that the dissociation of the dimer into two partially unfolded monomers takes place in the third step. Finally, the unfolding of the Blal NTD occurs at a GdmCI concentration of approx. 4 M. In summary, it is shown that the Blal CTD is structured, more flexible and less stable than the NTD upon GdmCI denaturation. These results contribute to the characterization of the Blal dimerization domain (i.e. CTD) involved in the induction process. [less ▲]

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See detailSolution structural study of BlaI: Implications for the repression of genes involved in beta-lactam antibiotic resistance
Van Melckebeke, H.; Vreuls, Christelle ULg; Gans, P. et al

in Journal of Molecular Biology (2003), 333(4), 711-720

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See detailDimerization and DNA binding properties of the Bacillus licheniformis 749/I BlaI repressor
Filée, Patrice ULg; Vreuls, Christelle ULg; Herman, Raphaël ULg et al

in Journal of Biological Chemistry (2003), 278(19), 16482-16487

In the absence of penicillin, the beta-lactamase encoding gene blaP of Bacillus licheniformis 749/I is negatively regulated by the transcriptional repressor BlaI. Three palindromic operator regions are ... [more ▼]

In the absence of penicillin, the beta-lactamase encoding gene blaP of Bacillus licheniformis 749/I is negatively regulated by the transcriptional repressor BlaI. Three palindromic operator regions are recognized by BlaI: two in the blaP promoter (OP1 and OP2) and one (OP3) in the promoter of the blaI-blaR1 operon. In this study, the dissociation constant of the purified BlaI dimer was estimated at 25 muM by equilibrium ultracentrifugation. Quantitative Western blot analysis indicates that the intracellular concentrations of BlaI in B. licheniformis 749/I and Bacillus subtilis transformed by a multicopy plasmid harboring the beta-lactamase locus (blaP-blaI-blaR1) were lower than (1.9 muM) or in the same range as (75 muM) the dissociation constant, respectively. This suggests that BlaI is partially dimeric in the cytoplasm of these strains and interacts in vivo with its operators as a preformed dimer. This hypothesis is supported by band shift assays on an operator containing a randomized half-operator sequence. The global dissociation constants of the operator-BlaI dimer complexes were measured by band shift assays and estimated as K-dOP1=1.7+/-0.5 10(-15) M-2, K-dOP2=3.3+/-0.9 10(-15) M-2, and K-dOP3=10.5+/-2.5 10(-15) M-2. The role of the DNA binding properties of BlaI on the beta-lactamase regulation is discussed. [less ▲]

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See detailSolution structural study of BlaI: implications for the repression of genes involved in beta-lactam antibiotic resistance.
Melckebeke, Helene Van; Vreuls, Christelle ULg; Gans, Pierre et al

in Journal of Molecular Biology (2003), 333(4), 711-20

beta-Lactamase and penicillin-binding protein PBP2' mediate staphylococcal resistance to beta-lactam antibiotics, which are otherwise highly clinically effective. Two repressors (BlaI and MecI) regulate ... [more ▼]

beta-Lactamase and penicillin-binding protein PBP2' mediate staphylococcal resistance to beta-lactam antibiotics, which are otherwise highly clinically effective. Two repressors (BlaI and MecI) regulate expression of these inducible proteins. Here, we present the first solution structure of the 82 amino acid residue DNA-binding domain of Bacillus licheniformis BlaI which is very similar in primary sequence to the medically significant Staphyloccocal BlaI and MecI proteins. This structure is composed of a compact core of three alpha-helices and a three-stranded beta-sheet typical of the winged helix protein (WHP) family. The protein/DNA complex was studied by NMR chemical shift comparison between the free and complexed forms of BlaI. Residues involved in DNA interaction were identified and a WHP canonical model of interaction with the operators is proposed. In this model, specific contacts occur between the base-pairs of the TACA motif and conserved amino acid residues of the repressor helix H3. These results help toward understanding the repression and induction mechanism of the genes coding for beta-lactamase and PBP2'. [less ▲]

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See detailAdvantages and drawbacks of nanospray for studying noncovalent protein-DNA complexes by mass spectrometry
Gabelica, Valérie ULg; Vreuls, Christelle ULg; Filée, Patrice ULg et al

in Rapid Communications in Mass Spectrometry : RCM (2002), 16(18), 1723-1728

The noncovalent complexes between the BlaI protein dimer (wild-type and GM2 mutant) and its double-stranded DNA operator were studied by nanospray mass spectrometry and tandem mass spectrometry (MS/MS ... [more ▼]

The noncovalent complexes between the BlaI protein dimer (wild-type and GM2 mutant) and its double-stranded DNA operator were studied by nanospray mass spectrometry and tandem mass spectrometry (MS/MS). Reproducibility problems in the nanospray single-stage mass spectra are emphasized. The relative intensities depend greatly on the shape of the capillary tip and on the capillary-cone distance. This results in difficulties in assessing the relative stabilities of the complexes simply from MS' spectra of protein-DNA mixtures. Competition experiments using MS/MS are a better approach to determine relative binding affinities. A competition between histidine-tagged BlaIWT (BlaIWTHis) and the GM2 mutant revealed that the two proteins have similar affinities for the DNA operator, and that they co-dimerize to form heterocomplexes. The low sample consumption of nanospray allows MS/MS spectra to be recorded at different collision energies for different charge states with 1 muL of sample. The MS/MS experiments on the dimers reveal that the GM2 dimer is more kinetically stable in the gas phase than the wild-type dimer. The MS/MS experiments on the complexes shows that the two proteins require the same collision energy to dissociate from the complex. This indicates that the rate-limiting step in the monomer loss from the protein-DNA complex arises from the breaking of the protein-DNA interface rather than the protein-protein interface. The dissociation of the protein-DNA complex proceeds by the loss of a highly charged monomer (carrying about two-thirds of the total charge and one-third of the total mass). MS/MS experiments on a heterocomplex also show that the two proteins BlaIWTHis and BlaIGM2 have slightly different charge distributions in the fragments. This emphasizes the need for better understanding the dissociation mechanisms of biomolecular complexes. [less ▲]

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