References of "De Pauw, Edwin"
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See detailIdentification of aphid salivary proteins: a proteomic investigation of Myzus persicae.
Harmel, Nicolas ULg; Letocart, E.; Cherqui, A. et al

in Insect Molecular Biology (2008), 17(2), 165-74

The role of insect saliva in the first contact between an insect and a plant is crucial during feeding. Some elicitors, particularly in insect regurgitants, have been identified as inducing plant defence ... [more ▼]

The role of insect saliva in the first contact between an insect and a plant is crucial during feeding. Some elicitors, particularly in insect regurgitants, have been identified as inducing plant defence reactions. Here, we focused on the salivary proteome of the green peach aphid, Myzus persicae. Proteins were either directly in-solution digested or were separated by 2D SDS-PAGE before trypsin digestion. Resulting peptides were then identified by mass spectrometry coupled with database investigations. A homemade database was constituted of expressed sequence tags from the pea aphid Acyrtosiphon pisum and M. persicae. The databases were used to identify proteins related to M. persicae with a nonsequenced genome. This procedure enabled us to discover glucose oxidase, glucose dehydrogenase, NADH dehydrogenase, alpha-glucosidase and alpha-amylase in M. persicae saliva. The presence of these enzymes is discussed in terms of plant-aphid interactions. [less ▲]

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See detailDioxin-like compounds in porpoises and seals from the southern North Sea: relationship with biological and ecological factors
Das, Krishna ULg; De Pauw, Edwin ULg; Eppe, Gauthier ULg et al

in Organohalogen Compounds (2008), 70

The North Sea represents a major ecosystem for the harbour porpoise (Phocoena phocoena) and the harbour seal (Phoca vitulina). The grey seal (Halichoerus grypus) occurs more occasionally in the southern ... [more ▼]

The North Sea represents a major ecosystem for the harbour porpoise (Phocoena phocoena) and the harbour seal (Phoca vitulina). The grey seal (Halichoerus grypus) occurs more occasionally in the southern part of the North Sea. Their population over this last decade has experienced major fluctuations likely linked to prey availability and seal epizootics. Despite being banned more than 30 years ago, levels of polychlorinated biphenyls (PCBs) in marine mammals are still of concern due to historical contamination of the North Sea. [less ▲]

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See detailProteome alteration induced by hTERT transfection of human fibroblast cells
Mazzucchelli, Gabriel ULg; Gabelica, Valérie ULg; Smargiasso, Nicolas ULg et al

in Proteome Science (2008), 6(1), 12

Background: Telomerase confers cellular immortality by elongating telomeres, thereby circumventing the Hayflick limit. Extended-life-span cells have been generated by transfection with the human ... [more ▼]

Background: Telomerase confers cellular immortality by elongating telomeres, thereby circumventing the Hayflick limit. Extended-life-span cells have been generated by transfection with the human telomerase reverse transcriptase (hTERT) gene. hTERT transfected cell lines may be of outstanding interest to monitor the effect of drugs targeting the telomerase activity. The incidence of hTERT gene transfection at the proteome level is a prerequisite to that purpose. The effect of the transfection has been studied on the proteome of human fibroblast (W138). Cytosolic and nuclear fractions of W138 cells, empty vector transfected W138 (W138-HPV) and hTERT W138 cells were submitted to a 2D-DIGE (Two-Dimensional Differential In-Gel Electrophoresis) analysis. Only spots that had a similar abundance in W138 and W138-HPV, but were differentially expressed in W138 hTERT were selected for MS identification. This method directly points to the proteins linked with the hTERT expression. Number of false positive differentially expressed proteins has been excluded by using control W138-HPV cells. The proteome alteration induced by hTERT W138 transfection should be taken into account in subsequent use of the cell line for anti-telomerase drugs evaluation. Results: 2D-DIGE experiment shows that 57 spots out of 2246 are significantly differentially expressed in the cytosolic fraction due to hTERT transfection, and 38 were confidently identified. In the nuclear fraction, 44 spots out of 2172 were selected in the differential proteome analysis, and 14 were identified. The results show that, in addition to elongating telomeres, hTERT gene transfection has other physiological roles, among which an enhanced ER capacity and a potent cell protection against apoptosis. Conclusion: We show that the methodology reduces the complexity of the proteome analysis and highlights proteins implicated in other processes than telomere elongation. hTERT induced proteome changes suggest that telomerase expression enhances natural cell repair mechanisms and stress resistance probably required for long term resistance of immortalized cells. Thus, hTERT transfected cells can not be only consider as an immortal equivalent to parental cells but also as cells which are over-resistant to stresses. These findings are the prerequisite for any larger proteomics aiming to evaluate anti-telomerase drugs proteome alteration and thus therapeutics induced cell reactions. [less ▲]

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See detailLNCaP prostate cancer imaging with biologically functionalized gold nanoparticles in 2D and 3D cell culture
Schol, Daureen ULg; Fleron, Maximilien ULg; Greisch, Jean - François et al

in Anticancer Research (2008), 28

One of the main objectives of this project is to realize and validate a versatile lab system composed of functionalized nanoparticles for diagnosis of different superficial and accessible cancers, e.g ... [more ▼]

One of the main objectives of this project is to realize and validate a versatile lab system composed of functionalized nanoparticles for diagnosis of different superficial and accessible cancers, e.g. prostate cancer. Gold nanorods have been synthesized and functionalized with antibodies targeting specific antigens on cancer cell lines. [less ▲]

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See detailOptoacoustic specific detection of prostate cancer using functionalized gold nanorods
Fleron, Maximilien ULg; Schol, Daureen ULg; Greisch, Jean-François et al

Poster (2007, November 16)

A major challenge in prostate cancer oncology is to develop more accurate imaging assessments than those currently available. Indeed, an efficient imaging technique which significantly improves the ... [more ▼]

A major challenge in prostate cancer oncology is to develop more accurate imaging assessments than those currently available. Indeed, an efficient imaging technique which significantly improves the sensitivity and specificity of the diagnostic and predicting the cancer behaviour would be extremely valuable. This project intends to prove the concept of using optoacoustic imaging in combination with biologically functionalized nanoparticles as an integrated biosensor based system for the production of specific and sensitive data for accurate diagnosis of prostate cancer. This concept results on the use of contrast agents which transform an incident luminous energy into local heating inducing a pressure wave detectable by acoustic (echography). For the optoacoustic detection, the nanoparticles used must present a maximum of absorption in the optical transparency window of the human tissues in order to allow their and subsequently the tissue specific excitations while avoiding unwanted destructive energy transfers. According to these characteristics (energy transfer by thermoelastic reaction), rod-like gold nanoparticles (stick form) with a maximum of absorption towards 760 nm were produced by using a “bottom-up” approach with dynamic templates (surfactant). These nanoparticles are then coupled with an antibody directed against the cancerous cells to guarantee the specific detection of the particles. The development of the biosensor is firstly performed to target the Prostate Specific Membrane Antigen (PSMA), a transmembrane protein considered as a suitable biomarker for prostate cancer. Detection and localisation of PSMA on LNCaP fixed cell surface was performed by immunostainning on monolayer cell culture and on spheroid slices. Then, by backscattered electron (BSE) microscopy analysis and two-photon luminescence imaging, detection of nanoparticles on fixed and living cell surface shows the successful binding of the biosensor to the cells expressing PSMA. In prospect, the detection of the biosensor will be tested on spheroids, on human biopsies and finally on in vivo models (mouse xenograft models). [less ▲]

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See detailTop-Down Proteomics using Matrix-Enhanced ISD
Demeure, Kevin ULg; Quinton, Loïc ULg; Gabelica, Valérie ULg et al

Poster (2007, October 11)

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See detailOptoacoustic specific detection of prostate cancer using functionalized gold nanorods
Fleron, Maximilien ULg; Schol, Daureen ULg; Greisch, Jean-François et al

Poster (2007, October 10)

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See detailConformationally driven gas-phase H/D exchange of dinucleotide negative ions
Balbeur, Dorothée ULg; Dehareng, Dominique ULg; De Pauw, Edwin ULg

in Journal of the American Society for Mass Spectrometry (2007), 18(10), 1827-1834

Gas-phase hydrogen/deuterium exchange of six deprotonated dinucleoticles with CD3OD was performed in the second hexapole of a Fourier transform ion-cyclotron resonance (FTICR) mass spectrometer. To ... [more ▼]

Gas-phase hydrogen/deuterium exchange of six deprotonated dinucleoticles with CD3OD was performed in the second hexapole of a Fourier transform ion-cyclotron resonance (FTICR) mass spectrometer. To complete these experiments, dynamic simulations were carried out to investigate the different conformations adopted by the dinucleotides. In the experimental conditions and in integrating the experimental and theoretical results, H/D exchange was shown to be controlled by hydrogen accessibility and not by the chemical nature of the heteroatom bearing the exchangeable hydrogen. A model including simultaneous H/D exchanges at the experimental time scale was used to reproduce the dinucleotide H/D exchange kinetic plots. The relay mechanism was not relevant for dinucleotides. This allowed the H/D exchange rates to be directly linked to conformations. [less ▲]

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See detailExploring the Formation Pathways of DNA G-Quadruplex Architectures
Rosu, Frédéric ULg; Poncelet, Harmonie; Teulade-Fichou, Marie-Paule et al

Conference (2007, September 07)

Guanine-rich DNA strands can form the so-called G-quadruplex architectures due to the formation of quartets of guanines linked by 8 hydrogen bonds. G-quadruplexes are further stabilized by the inclusion ... [more ▼]

Guanine-rich DNA strands can form the so-called G-quadruplex architectures due to the formation of quartets of guanines linked by 8 hydrogen bonds. G-quadruplexes are further stabilized by the inclusion of cations between the G-quartets. The abundance of G-rich regions throughout the genome and their very presence in telomeric regions made G-quadruplexes interesting targets. NMR and crystallographic studies of G-quadruplex structures revealed amazing variety in the G-quadruplex topologies. The next challenge will be to understand the rules governing the formation of the various topologies, in order to predict relevant G-quadruplexes in the genome, and in order to act rationally on their formation or disruption. To date, only few experimental [1] or theoretical [2] studies have been devoted to investigating the mechanisms of G-quadruplex formation. We report here a detailed investigation of DNA G-quadruplex formation pathways using electrospray mass spectrometry (ESI-MS). The sequences TGnT (n = 3-6) were purchased from Eurogentec (Seraing, Beliugm). ESI-MS experiments were performed in the negative ion mode on a Q-TOF Ultima Global (Waters, Manchester, UK). The cation used was ammonium (up to 150 mM). Experiments were performed in the presence and absence of methanol (up to 20%) as co-solvent. ESI-MS allows counting both the number of strands and the number of cations in each intermediate. We could confirm the presence of transient dimer and trimer intermediates in low abundance. More unexpectedly, ESI-MS also reveals unambiguously the formation of pentamers which contain ammonium cations. The pentamers slowly convert into tetramers. Counting the number of included cations also revealed that, in the case of (TG6T)4, inclusion of four ammonium cations is fast, while the inclusion of the last ammonium ion is very slow. We also found that the addition of methanol (initially added to obtain higher ion intensities) significantly increases the rate of G-quadruplex formation. Finally, we also investigated the role of G-quadruplex ligands in the rate of formation of G-quadruplexes. We could classify the ligands according to their increase of G-quadruplex formation kinetics, and distinguish the intermediates. Interestingly, one ligand showed formation of a higher-order structure by bridging two G-quadruplexes. Acknowledgement: The authors thank the FRS-FNRS for their support. References: [1] J. Gros et al., Nucleic Acids Res., 2007, doi:10.1093/nar/gkm111. [2] R. Stefl et al., Biophys. J., 2003, 85(3), 1787-1804. [less ▲]

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See detailDevelopment of a new integrated biosensor system for an accurate diagnosis of prostate cancer using optoacoustic detection
Fleron, Maximilien ULg; Schol, Daureen ULg; Greisch, Jean-François et al

Poster (2007, June 09)

The prostate cancer is the most common male-specific cancer observed in the European Union and is the second leading cause of cancer death in men in our industrialized countries. The choice of treatment ... [more ▼]

The prostate cancer is the most common male-specific cancer observed in the European Union and is the second leading cause of cancer death in men in our industrialized countries. The choice of treatment and its efficiency is largely dependent on the stage and on the degree of advancement of the cancer when it is diagnosed. Screening procedures like digital rectal examination (DRE) and free prostate specific antigen (PSA) level testing are well established but lack accuracy, yielding only 80% of prostate cancers diagnosed in an early stage. By providing a more accurate and precise tool for diagnosing prostate cancer in its early stages, the percentage of curable cancer patients would increase radically. Current imaging techniques have limited value, thus a major challenge in current prostate cancer oncology is to develop more accurate imaging assessments. An efficient imaging technique which significantly improves the sensitivity and specificity of diagnosing, staging and predicting the behaviour of prostate cancer would be extremely valuable. The ADONIS Project intends to prove the concept of using optoacoustic imaging in combination with biologically functionalized nanoparticles as an integrated biosensor based system for the production of specific and sensitive data for accurate diagnosis of prostate cancer. The achievement of this objective requires excellent know-how on a variety of scientific and technologic fields, brought by the partners of ADONIS, coming from five European countries, such as laser and ultrasound technologies and image reconstruction techniques, the bio-functionalization of nanoparticles, the system integration and, finally, experiments and competent evaluation of the results for their application potential. The development of the biosensor is firstly performed to target the Prostate Specific Membrane Antigen (PSMA), a transmembrane protein considered as a suitable biomarker for prostate cancer and which is under intense investigation for use as an imaging and therapeutic target. To allow the detection optimization of the biosensor, a 3D cellular culture technique (Rotating Cell Culture System) is developed with LNCaP cells (a human prostate carcinoma cell line reported to express PSMA) to be closest to the in vivo aspect for which a three-dimensional aspect of tumor for the biosensor detection is needed. Detection and localisation of PSMA on LNCaP cell surface was performed by immunostainning on monolayer culture and on spheroid slices. Then, by backscattered electron (BSE) microscopy analysis, detection of nanoparticles on cells surface shows the successful binding of the biosensor to the cells expressing PSMA. In prospect, the detection of the biosensor will be tested on large spheroids and finally tested on in vivo model. [less ▲]

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See detailDevelopment and validation of a multi-residue method for pesticide determination in honey using on-column liquid-liquid extraction and liquid chromatography-tandem mass spectrometry
PIRARD, Catherine ULg; Widart, Joëlle ULg; Nguyen, Bach Kim ULg et al

in Journal of Chromatography. A (2007), 1152(1-2), 116-123

We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran ... [more ▼]

We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran, Methiocarb, Pirimicarb, Dimethoate, Fipronil, Imidacloprid; herbicides: Amidosulfuron, Rimsulfuron, Atrazine, Simazine, Chloroturon, Linuron, Isoxaflutole, Metosulam; fungicides: Diethofencarb) and 2 metabolites (Methiocarb sulfoxide and 2-Hydroxytertbutylazine) in honey. This method is based on an on-column liquid liquid extraction (OCLLE) using diatomaceous earth as inert solid support and liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS). Method specificity is ensured by checking retention time and theoretical ratio between two transitions from a single precursor ion. Linearity is demonstrated all along the range of concentration that was investigated, from 0.1 to 20 ng g(-1) raw honey, with correlation coefficients ranging from 0.921 to 0.999, depending on chemicals. Recovery rates obtained on home-made quality control samples are between 71 and 90%, well above the range defined by the EC/657/2002 document, but in the range we had fixed to ensure proper quantification, as levels found in real samples could not be corrected for recovery rates. Reproducibility is found to be between 8 and 27%. Calculated CC alpha and CC beta (0.0002-0.943 mg g(-1) for CC alpha, and 0.0002-1.232 ng g(-1) for CCP) show the good sensitivity attained by this rnulti-residue analytical method. The robustness of the method has been tested in analyzing more than 100 raw honey samples collected from different areas in Belgium, as well as some wax and bee samples, with a slightly adapted procedure. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailTop-Down Proteomics using Matrix-Enhanced ISD
Demeure, Kevin ULg; Quinton, Loïc ULg; Gabelica, Valérie ULg et al

Conference (2007, June 05)

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See detailAn immuno-PF2D-MS/MS proteomic approach for bacterial antigenic characterization: To Bacillus and beyond
Ruelle, Virginie ULg; Falisse-Poirier, Nandini; Elmoualij, Benaïssa ULg et al

in Journal of Proteome Research (2007), 6(6), 2168-2175

We are confronted daily to unknown microorganisms that have yet to be characterized, detected, and/ or analyzed. We propose, in this study, a multidimensional strategy using polyclonal antibodies ... [more ▼]

We are confronted daily to unknown microorganisms that have yet to be characterized, detected, and/ or analyzed. We propose, in this study, a multidimensional strategy using polyclonal antibodies, consisting of a novel proteomic tool, the ProteomeLab PF2D, coupled to immunological techniques and mass spectrometry ( i-PF2D-MS/MS). To evaluate this strategy, we have applied it to Bacillus subtilis, considered here as our unknown bacterial model. [less ▲]

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See detailGlobal strategy for the development of estrogenic compounds detection screening test
Collodoro, Mike ULg; Makasinga, Elu; Lemaire, Pascale ULg et al

Poster (2007, May)

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