References of "De Pauw, Edwin"
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See detailFundamental Studies on Poly(2-oxazoline) Side Chain Isomers Using Tandem Mass Spectrometry and Ion Mobility-Mass Spectrometry
Haler, Jean ULiege; de la Rosa, Victor R.; Massonnet, Philippe ULiege et al

in Journal of the American Society for Mass Spectrometry (in press)

When polymer mixtures become increasingly complex, the conventional analysis techniques become insufficient for complete characterization. Mass spectrometric techniques can satisfy this increasing demand ... [more ▼]

When polymer mixtures become increasingly complex, the conventional analysis techniques become insufficient for complete characterization. Mass spectrometric techniques can satisfy this increasing demand for detailed sample characterization. Even though isobaric polymers are indistinguishable using simple mass spectrometry (MS) analyses, more advanced techniques such as tandem MS (MS/MS) or ion mobility (IM) can be used. Here, we report proof of concept for characterizing isomeric polymers, namely poly(2-n-propyl-2-oxazoline) (Pn-PrOx) and poly(2-isopropyl-2-oxazoline) (Pi-PrOx), using MS/MS and IM-MS. Pi-PrOx ions lose in intensity at higher accelerating voltages than Pn-PrOx ions during collision-induced dissociation (CID) MS/MS experiments. A Pn/i-PrOx mixture could also be titrated using survival yield calculations of either precursor ions or cation ejection species. IM-MS yielded shape differences in the degree of polymerization (DP) regions showing the structural rearrangements. Combined MS techniques are thus able to identify and deconvolute the molar mass distributions of the two isomers in a mixture. Finally, the MS/MS and IM-MS behaviors are compared for interpretation. [less ▲]

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See detailFrom noise to signal: Kendrick mass filtering for high-resolution mass spectrometry imaging analysis
Mc Cann, Andréa ULiege; Kune, Christopher ULiege; Arguelles Arias, Anthony ULiege et al

Poster (2019, April 14)

Introduction Over the last years, lots of progress have been done in the development of mass spectrometry imaging, making the technique more and more accessible for various applications, such as ... [more ▼]

Introduction Over the last years, lots of progress have been done in the development of mass spectrometry imaging, making the technique more and more accessible for various applications, such as biomarkers discovery or bioactive compounds identification. However, the progresses made in terms of spatial and instrumental resolution has for consequences the dramatic increase of dataset size, shifting the burden from data production to data analysis. We propose here to use a semi-targeted method based on Kendrick mass defect (KMD) analysis to immediately identify the chemistry-related compounds in mass spectrometry imaging applied to microbiology samples. Thanks to an in-house software, we are now able to better understand the bacteria-bacteria interactions. Materials and methods Bacillus velezensis GA1 and Pseudomonas sp. CMR12a were inoculated on a semi-solid agar-based medium and incubated at 30°C. Region of interest was cut directly from the petri dish and transferred to the target ITO plate, previously covered with double sided conductive carbon tape. This assembly was then put in a vacuum desiccator until complete drying (overnight), and covered with HCCA matrix. Mass spectrometry images were obtained using a FT-ICR mass spectrometer (9.4T SolariX, Bruker Daltonics, Bremen, Germany). Data analysis was performed on an in-house software. Results & Discussion Thanks to the KMD analysis, we were able to directly compare and identify the nature of the compounds detected in MSI such as lipids (1) or lipopeptides (2a), without the need of an extensive database search. It was also possible to identify some lipopeptides degradation occurring nearby Pseudomonas (2b). Thanks to our in-house software, the compounds with a similar chemistry can now be filtrated and the image can be reconstructed, removing thus the noise and focusing only on the signal. [less ▲]

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See detailGas-Phase Dynamics of Collision Induced Unfolding, Collision Induced Dissociation, and Electron Transfer Dissociation-Activated Polymer Ions
Haler, Jean ULiege; Massonnet, Philippe ULiege; Far, Johann ULiege et al

in Journal of the American Society for Mass Spectrometry (2019), 30(4), 563572

Polymer characterizations are often performed using mass spectrometry (MS). Aside from MS and different tandem MS (MS/MS) tech- niques, ion mobility–mass spectrometry (IM-MS) has been recently added to ... [more ▼]

Polymer characterizations are often performed using mass spectrometry (MS). Aside from MS and different tandem MS (MS/MS) tech- niques, ion mobility–mass spectrometry (IM-MS) has been recently added to the inventory of char- acterization technique. However, only few studies have focused on the reproducibility and robust- ness of polymer IM-MS analyses. Here, we per- form collisional and electron-mediated activation of polymer ions before measuring IM drift times, collision cross-sections (CCS), or reduced ion mobilities (K0). The resulting IM behavior of different activated product ions is then compared to non-activated native intact polymer ions. First, we analyzed collision induced unfolding (CIU) of precursor ions to test the robustness of polymer ion shapes. Then, we focused on fragmen- tation product ions to test for shape retentions from the precursor ions: cation ejection species (CES) and product ions with m/z and charge state values identical to native intact polymer ions. The CES species are formed using both collision induced dissociation (CID) and electron transfer dissociation (ETD, formally ETnoD) experiments. Only small drift time, CCS, or K0 deviations between the activated/formed ions are observed compared to the native intact polymer ions. The polymer ion shapes seem to depend solely on their mass and charge state. The experiments were performed on three synthetic homopolymers: poly(ethoxy phosphate) (PEtP), poly(2-n-propyl- 2-oxazoline) (Pn-PrOx), and poly(ethylene oxide) (PEO). These results confirm the robustness of polymer ion CCSs for IM calibration, especially singly charged polymer ions. The results are also discussed in the context of polymer analyses, CCS predictions, and probing ion–drift gas interaction potentials. [less ▲]

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See detailIon mobility mass spectrometry for lipopeptides analysis
Mc Cann, Andréa ULiege; Kune, Christopher ULiege; Far, Johann ULiege et al

Poster (2019, March 31)

Cyclic lipopeptides (CLPs) are produced by bacteria in a ribosome independent manner and consists in a hydrophilic peptide linked to a B-hydroxy fatty acid chain. Despite CLPs have relatively low ... [more ▼]

Cyclic lipopeptides (CLPs) are produced by bacteria in a ribosome independent manner and consists in a hydrophilic peptide linked to a B-hydroxy fatty acid chain. Despite CLPs have relatively low molecular weight (between 800 and 2,000 Da), the analysis of lipopeptides remains challenging due to the wide variety of synthetized isoforms differing in fatty acid chain length, in methyl group branching position, and in the nature of the amino-acids residues. These isoforms are suspected to have different biological activities requiring development of reliable methods for CLPs identification and characterization. In this work, we present an original approach combining UPLC and ion mobility - mass spectrometry at high resolving powers to separate and identify the different species. Lipopeptides were separated by UPLC (I-class, Waters, U.K.) on a C18 BEH column and identified by CID MS/MS mass spectrometry. Ion mobility – mass spectrometry (IM-MS) measurements were performed on a trapped Ion Mobility Mass Spectrometer (TimsTOF, Bruker Daltonics, U.S.A.). Accurate Collison Cross Section (CCS) were obtained in both positive and negative mode and compared with theoretical CCS obtained by the trajectory method from IMoS V2. Separation of lipopeptides such as surfactins, iturins, or mycosubtilins was successfully performed by reverse phase liquid chromatography. Lipopeptides were separated according to lipid chain length and according to the branching position of the methyl group (iso/anteiso/linear). Ion mobility analysis with computational chemistry support gave additional information on the lipopeptides structure and family. Structural information are obtained by experimental and theoretical CCS comparison while the lipopeptides family could be determined with CCS/mass trends. These results pave the way to a new strategy for fast lipopeptides identification and could potentially contribute to lipopeptides structure elucidation. [less ▲]

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See detailDevelopment of bimetallic nanoparticles for Surface-Assisted Laser Desorption/Ionisation Mass Spectrometry imaging of small molecules
Verdin, Alexandre ULiege; Malherbe, Cédric ULiege; Bertrand, Virginie ULiege et al

Poster (2019)

Metallic nanoparticles (NPs) receive increasing attention as desorption/ionization substrate for Surface-Assisted Laser Desorption Ionization-MS (SALDI-MS) [1]. Metallic NPs offer high extinction ... [more ▼]

Metallic nanoparticles (NPs) receive increasing attention as desorption/ionization substrate for Surface-Assisted Laser Desorption Ionization-MS (SALDI-MS) [1]. Metallic NPs offer high extinction coefficients of the ionization laser (in the UV-Visible range of wavelengths) and are able to ionize small molecules with little interferences in the low m/z range with a simple sample preparation [2]. SALDI-MSI is adapted to study the variations of the molecular composition associated with various diseases and to visualize the localization of pertinent small molecules in complex biological tissues. Innovative Au@Ag (core@shell) bimetallic NPs are interesting for SALDI applications, especially because controlling the thickness of the Ag shell around the Au core allows the tuning of the absorption in near-UV. The Au@Ag NPs permits to vary the energy transfer for an efficient ionization and desorption of analytes adsorbed to the NPs. Moreover Au@Ag NPs can also also be used for Surface-Enhanced Raman Spectroscopy (SERS) imaging. We report here a study of ovarian cancer tissue using Au@Ag NPs to localize the tumor by SERS imaging and to gain molecular insight of tumors by SALDI-MSI. [less ▲]

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See detailMicroproteomic Profiling of High-Grade Squamous Intraepithelial Lesion of the Cervix: Insight into Biological Mechanisms of Dysplasia and New Potential Diagnostic Markers
Pottier, Charles ULiege; Kriegsmann, M.; Alberts, D. et al

in Proteomics. Clinical Applications (2019), 13(1)

Purpose: High-grade squamous intraepithelial lesion (HSIL) is a known precursor for squamous cell carcinoma of uterine cervix. Although it is known that SILs are associated to infection by human ... [more ▼]

Purpose: High-grade squamous intraepithelial lesion (HSIL) is a known precursor for squamous cell carcinoma of uterine cervix. Although it is known that SILs are associated to infection by human papillomavirus, downstream biological mechanisms are still poorly described. In this study, we compared the microproteomic profile of HSIL to normal tissues: ectocervix (ectoC) and endocervix (endoC). Experimental design: Tissue regions of endoC, ectoC, and HSlL were collected by laser microdissection (3500 cells each) from five patients. Samples were processed and analyzed using our recently developed laser microdissection-based microproteomic method. Tissues were compared in order to retrieve HSIL's proteomic profile. Potentially interesting proteins for pathology were stained by immunohistochemistry. Results: We identified 3072 proteins among the fifteen samples and 2386 were quantified in at least four out of the five biological replicates of at least one tissue type. We found 236 proteins more abundant in HSIL. Gene ontology enrichments revealed mechanisms of DNA replication and RNA splicing. Despite the squamous nature of HSIL, a common signature between HSIL and endoC could be found. Finally, potential new markers could support diagnosis of dysplasia in SILs. Conclusion and clinical relevance: This microproteomic investigation of HSIL gives insights into the biology of cervical precancerous lesions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [less ▲]

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See detailIdentification of new bioactive peptides from Kefir milk through proteopeptidomics: Bioprospection of antihypertensive molecules
Amorim, F. G.; Coitinho, L. B.; Dias, A. T. et al

in Food Chemistry (2019), 282

Kefir, a probiotic beverage prepared from fermented milk, has been associated with antihypertensive activity. However, the bioactive molecules responsible for this activity still remain unclear. Therefore ... [more ▼]

Kefir, a probiotic beverage prepared from fermented milk, has been associated with antihypertensive activity. However, the bioactive molecules responsible for this activity still remain unclear. Therefore, in this study we aim to evaluate the mechanisms of the antihypertensive effects of Kefir in the two-kidney one-clip hypertension model, and to bioprospect for bioactive peptides identified by proteomic methodologies. Treatment with Kefir was performed via gavage, and resulted in a 37 mmHg reduction in systolic arterial pressure and 19% inhibition of angiotensin converting enzyme (ACE) activity. For the proteopeptidomic study, the protein extract of Kefir beverage and non-fermented bovine milk were analysed by MALDI-TOF mass spectrometry, and their tryptic digestion products sequenced via Shotgun proteomics (Q-Exactive mass spectrometer). A list of 35 peptides with potential hypertensive activity due to ACE inhibition were identified. These results demonstrate the benefits of Kefir products, and may guide the design of new antihypertensive drugs. © 2019 Elsevier Ltd [less ▲]

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See detailTowards the use of ion mobility mass spectrometry-derived collision cross section as a screening approach for unambiguous identification of targeted pesticides in food
Goscinny, Severine; McCullagh, Michael; Far, Johann ULiege et al

in Rapid Communications in Mass Spectrometry (2019)

Rationale Mass Spectrometry (MS) is the reference method for the screening of ultra‐trace residues of pesticides in food because MS offers the required selectivity/sensitivity to gather information and ... [more ▼]

Rationale Mass Spectrometry (MS) is the reference method for the screening of ultra‐trace residues of pesticides in food because MS offers the required selectivity/sensitivity to gather information and enable the analyst to make informed decisions during the identification process. Here we present and discuss the use of collision cross section (CCS) values in addition to mass accuracy and retention times in a pesticide screening method that integrates all the features offered by coupling UPLC with IMS‐MS. Methods All experiments were carried out using UHPLC coupled to a travelling wave ion mobility mass spectrometer equipped with an ESI source working in positive mode. An in‐house library containing 200 pesticides was built using standard solutions and used as reference for a TWCCS calibration study. Matrix extracts were analysed to evaluate the performance of different screening workflows based on TWCCS, mass accuracy and retention times. Results The results proved that TWCCS values are very consistent, as the measured values do not differ more than 1% from the in‐house reference data library and emphasized the importance of the first low m/z mobility calibration point to guarantee full independence from instrument parameters and calibrant. The screening procedure was simplified to a single step by fully exploiting the content of ion mobility without generating any false detections, either positive or negative from spiked samples and a previous proficiency test. Conclusions The screening approach proposed in this study is unconventional and based on large mass accuracy (20 ppm) and retention time windows (0.5 min) to capture; in a first step, a maximum of detected compounds. Compounds of interest are then identified by comparing measured collision cross sections with the measured reference library collision cross sections (with relative error tolerance lower than 2%). [less ▲]

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See detailAnalytical tool for lipopeptide identification
Mc Cann, Andréa ULiege; Kune, Christopher ULiege; Far, Johann ULiege et al

Conference (2018, November 30)

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See detailCombination of Capillary Electrophoresis and Ion mobility coupled to Mass Spectrometry and Theoretical Calculations for cysteine connectivity identification in peptides bearing two intra-molecular disulfide bonds
Delvaux, Cédric ULiege; Massonnet, Philippe ULiege; Kune, Christopher ULiege et al

Conference (2018, November 06)

Disulfide bonds are post translational modification playing essential roles in the biological activity and stability of numerous peptides and proteins. Intra-molecular disulfide bonds are found in various ... [more ▼]

Disulfide bonds are post translational modification playing essential roles in the biological activity and stability of numerous peptides and proteins. Intra-molecular disulfide bonds are found in various natural-occurring peptides such as animal venoms. In such peptides, the appropriate cysteine connectivity provides the required conformation for efficient binding to their molecular targets, which ensures their bioactivity. The characterization of cysteine pairing is still a challenging issue in the analysis of peptides targeting pharmaceutical or pharmacological utilizations. Thus, the use of sensitive, robust and efficient characterization techniques to access the cysteine pairing is crucial. In our workflow,the separation of the disulfide isomers of three peptides bearing two intra-molecular disulfide bonds but different cysteine connectivities have been tested using Capillary Zone Electrophoresis (CZE) and Ion Mobility (IM) coupled to Mass Spectrometry (MS). Results show that CZE-MS and IM-MS act as complementary techniques to unambiguously determine the cysteine connectivity of a given peptide. Indeed, the combination of the relative migration time to a reference peptide in CZE-MS, the drift time in IM-MS and the generation of fragments by Collision Induced Dissociation (CID) led to the attribution of the disulfide connectivities in all studied cases. Finally, theoretical calculations were performed to model the different structures in gas phase and solution, supporting the experimental observations on the basis of the predicted physicochemical properties. [less ▲]

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See detailEffectiveness and limitations of computational chemistry and mass spectrometry in the rational design of target‐specific shift reagents for ion mobility spectrometry
Kune, Christopher ULiege; Haler, Jean ULiege; Far, Johann ULiege et al

in Chemphyschem: A European Journal of Chemical Physics and Physical Chemistry (2018)

Ion mobility spectrometry (IMS) is a gas‐phase separation technique based on ion mobility differences in an electric field. It is largely used for the detection of specific ions such as small molecule ... [more ▼]

Ion mobility spectrometry (IMS) is a gas‐phase separation technique based on ion mobility differences in an electric field. It is largely used for the detection of specific ions such as small molecule explosives. IMS detection system includes the use of e.g. a Faraday plate or mass spectrometry (MS). The presence of interfering ion signals in standalone IMS may lead to the detection of false positives or negatives due to e.g. lacking resolving power. In this case, selective mobility shifts obtained using shift reagents (SR), i.e. ligands complexing a specific target, can bring help. The effectiveness of an SR strategy relies on the SR‐target ion selectivity. The crucial step lies in the SR design. The aim of this paper is to present an efficient interplay of experimental ion mobility mass spectrometry (IMMS) and predictive computational chemistry using various levels of computational efforts for rationally designing target‐specific SR. Mass spectrometry is used to evaluate the efficiency of the SR selectivity with identification and semi‐quantification of free and complexed ions. Minimal computational efforts allow the design of the SR, predict the SR‐target ion relative stabilities, and prediction of ion mobility shifts. We demonstrate our approach using crown ethers and β‐cyclodextrin to selectively shift interfering perchlorate, amino acids and diaminonaphthalene isomers. We also release the software ParsIMoS for straightforward use of ion mobility calculator IMoS. [less ▲]

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See detailMetallic nanoparticles: an interesting option for mass spectrometry imaging of small molecules in tissues
Verdin, Alexandre ULiege; Müller, Wendy ULiege; Bertrand, Virginie ULiege et al

Poster (2018, July 05)

MALDI mass spectrometry imaging is a central technique for the visualisation and identification of a wide variety of molecules in biological samples, especially in tissues slides. However, organic ... [more ▼]

MALDI mass spectrometry imaging is a central technique for the visualisation and identification of a wide variety of molecules in biological samples, especially in tissues slides. However, organic matrices used for the desorption and ionisation of molecules suffers from major limitations, particularly for the analysis of small molecules due to interferences from the matrix in the low m/z range. In this preliminary study we compared the performances of 9-aminoacridine, a well known organic matrix used for small molecules anaylsis, and metallic nanoparticles to evaluate the information obtained from both method. Ionisation by nanoparticles is known as Surface-Assisted Laser Desorption Ionisation (SALDI). Metallic nanoparticles seem to be a promising substrate for MS analysis of small compounds in tissues and reveals information that are complementary to those obtained by MALDI. [less ▲]

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See detailMass spectrometry based techniques for lipopeptides analysis
Mc Cann, Andréa ULiege; Delvaux, Cédric ULiege; Far, Johann ULiege et al

Conference (2018, July 05)

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See detailResolving Poly(2-oxazoline) Side Chain Isomers using Tandem Mass Spectrometry and Ion Mobility-Mass Spectrometry
Haler, Jean ULiege; de la Rosa, Victor R.; Massonnet, Philippe ULiege et al

Poster (2018, July 05)

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See detailIon mobility mass spectrometry for lipopeptides analysis
Mc Cann, Andréa ULiege; Delvaux, Cédric ULiege; Far, Johann ULiege et al

Scientific conference (2018, July 04)

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See detailMicroproteomic profiling og high-grade squamous intraepithelial lesions of the cervix
Pottier, Charles ULiege; Kriegsmann, Mark; Smargiasso, Nicolas ULiege et al

Poster (2018, June 06)

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See detailRevisiting protomers of aniline by high-resolution ion mobility spectrometry, capillary electrophoresis-mass spectrometry, and abinitio calculations
Kune, Christopher ULiege; Delvaux, Cédric ULiege; Haler, Jean ULiege et al

Poster (2018, June 05)

The detection of two stable tautomers of protonated aniline, the amino-protonated and the protonated carbone in para position (“Cpara-protonated”), are already reported in the literature. The use of ... [more ▼]

The detection of two stable tautomers of protonated aniline, the amino-protonated and the protonated carbone in para position (“Cpara-protonated”), are already reported in the literature. The use of traveling wave ion mobility spectrometry (TWIMS) spotlights a possible conversion between both of these tautomers. Moreover, the presence of phenol strongly suggests that water adduct(s) is/are involved during this tautomerisation. The use of high resolution ion mobility - mass spectrometry also suggests tautomers conversion and the presence of other metastable species of protonated aniline than the Cpara-protonated and amino-protonated aniline. These observations support that the measurement of protomers ratio should be affect by gas phase reactions. Aqueous and non-aqueous capillary electrophoresis results show the effect of the solvents. The rate of tautomers conversion seems to be higher in protic solvent (water) than aprotic solvent (acetonitrile). [less ▲]

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See detailResolving Poly(2-oxazoline) Side Chain Isomers using Tandem Mass Spectrometry and Ion Mobility-Mass Spectrometry
Haler, Jean ULiege; de la Rosa, Victor R.; Massonnet, Philippe ULiege et al

Poster (2018, June 05)

Detailed reference viewed: 16 (3 ULiège)