Suche

Segura Jean-Manuel

Professeur-e HES Associé-e, Responsable de l'orientation Chimie analytique

Hauptkompetenzen

Point-of-care diagnostics (POCT)

Professeur-e HES Associé-e, Responsable de l'orientation Chimie analytique

Büro: ENP.19.N507

HES-SO Valais-Wallis - Haute Ecole d'Ingénierie
Rue de l'Industrie 23, 1950 Sion, CH

Bereich
Chimie et sciences de la vie

Hauptstudiengang
Technologies du vivant

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2021

Performance evaluation of the Simtomax® CoronaCheck rapid diagnostic test

Scientifique ArODES

Ducrest Percevent J., Freymond A., Segura Jean-Manuel

Journal of Virological Methods, 2021, vol. 294, article no. 114178

Link zur Publikation

Zusammenfassung:

The aim of this study was to evaluate the diagnostic performance of Simtomax® CoronaCheck, a serology rapid diagnostic test (RDT) for the detection of IgG and IgM against SARS-CoV-2. 48 plasma samples positive for SARS-CoV-2 based on RT-PCR and 98 negative control samples were studied. Diagnostic performance of the IgG/IgM RDT was assessed against RT-PCR and the electro-chemiluminescence immunoassay (ECLIA) Elecsys® Anti-SARS-CoV-2 total Ig. Overall, the RDT sensitivity was 92 % (95 % confidence interval [95 %CI]: 79−97), specificity 97 % (95 % CI: 91−99 %), PPV 94 % (95 % CI: 81−98) and the NPV 96 % (95 % CI: 89−99). When considering only samples collected ≥ 15 days post-symptoms (DPS), the sensitivity increased to 98 % (95 %CI: 86‐100) and the specificity was 97 % (95 % CI: 91−99 %). Two samples with 180 DPS were still positive for IgG. Globally, this IgG/IgM RDT displayed a high diagnostic accuracy for SARS‐CoV‐2 IgG/IgM detection in plasma samples in high COVID‐19 prevalence settings. It could be effectively used, in absence of facilities for routine diagnostic serology, for samples with a DPS between 15 and 180 days.

2020

Analytical platforms at swiss universities of applied sciences

Scientifique ArODES

Berchtold Christian, Christen Verena, Bourgeois Jean-Pascal, Dabros Michal, Nicolet Olivier, Portmann Cyril, Roth Samuel, Vorlet Olivier, Demuth Caspar, Kern Susanne, Yeretzian Chahan, Hoffmann Anika, Kalman Franka, Marcon Nadia, Pfeifer Marc E., Piantini Umberto, Prim Denis, Segura Jean-Manuel, Zollinger Mathieu, Schlotterbeck Götz

CHIMIA International Journal for Chemistry, 2020, vol. 74, no. 7/8, pp. 618-628

Link zur Publikation

Zusammenfassung:

Numerous projects and industrial and academic collaborations benefit from state-of-the-art facilities and expertise in analytical chemistry available at the Swiss Universities of Applied Sciences. This review summarizes areas of expertise in analytical sciences at the University of Applied Sciences and Arts Northwestern Switzerland (FHNW), the University of Applied Sciences and Arts Western Switzerland (HES-SO), and the Zurich University of Applied Sciences (ZHAW). We briefly discuss selected projects in different fields of analytical sciences

2017

Continuous processes and flow chemistry at the Universities of Applied Sciences in Switzerland

Scientifique ArODES

Allemann Christophe, Marti Roger, Vorlet Olivier, Martin Oliver, Riedlberger Peter, Leonhardt Tobias, Gössi Angelo, Riedl Wolfgang, Segura Jean-Manuel, Crelier Simon

CHIMIA International Journal for Chemistry, 2017, vol. 71, no. 7/8, pp. 525-527

Link zur Publikation

Zusammenfassung:

This article provides an overview of activities in the fields of continuous processes, flow chemistry and microreactors at the Universities of Applied Sciences in Switzerland.

A short double-stapled peptide inhibits respiratory syncytial virus entry and spreading

Scientifique ArODES

Gaillard Vanessa, Galloux Marie, Garcin Dominique, Eléouët Jean-François, Le Goffic Ronan, Larcher Thibaut, Rameix-Welti Marie-Anne, Boukadiri Abdelhak, Héritier Julien, Segura Jean-Manuel, Baechler Elodie, Arrell Miriam, Mottet-Osman Geneviève, Nyanguile Origène

Antimicrobial Agents and Chemotherapy, 2017, vol. 61, no. 4, article no. e02241-16

Link zur Publikation

Zusammenfassung:

Synthetic peptides derived from the heptad repeat (HR) of fusion (F) proteins can be used as dominant negative inhibitors to inhibit the fusion mechanism of class I viral F proteins. Here, we have performed a stapled-peptide scan across the HR2 domain of the respiratory syncytial virus (RSV) F protein with the aim to identify a minimal domain capable of disrupting the formation of the postfusion six-helix bundle required for viral cell entry. Constraining the peptides with a single staple was not sufficient to inhibit RSV infection. However, the insertion of double staples led to the identification of novel short stapled peptides that display nanomolar potency in HEp-2 cells and are exceptionally robust to proteolytic degradation. By replacing each amino acid of the peptides by an alanine, we found that the substitution of residues 506 to 509, located in a patch of polar contacts between HR2 and HR1, severely affected inhibition. Finally, we show that intranasal delivery of the most potent peptide to BALB/c mice significantly decreased RSV infection in upper and lower respiratory tracts. The discovery of this minimal HR2 sequence as a means for inhibition of RSV infection provides the basis for further medicinal chemistry efforts toward developing RSV fusion antivirals.

2016

Quantification of the production of hydrogen peroxide H2O2 during accelerated wine oxidation

Scientifique ArODES

Héritier Julien, Bach Benoît, Schönenberger Patrik, Gaillard Vanessa, Ducruet Julien, Segura Jean-Manuel

Food Chemistry, 2016, vol. 211, pp. 957-962

Link zur Publikation

Zusammenfassung:

Understanding how wines react towards oxidation is of primary importance. Here, a novel approach was developed based on the quantitative determination of the key intermediate H2O2 produced during accelerated oxidation by ambient oxygen. The assay makes use of the conversion of the non-fluorescent Amplex Red substrate into a fluorescent product in presence of H2O2. The total production of H2O2 during 30 min was quantified with low within-day and between-day variabilities. Polymerized pigments, but not total polyphenols, played a major role in the determination of H2O2 levels, which were lower in white wines than red wines. H2O2 amounts also increased with temperature and the addition of metal ions, but did not depend on the concentration of many other wine constituents such as SO2. H2O2 levels did not correlate with anti-oxidant properties. We believe that this novel methodology might be generically used to decipher the oxidation mechanisms in wines and food products.

Rapid and straightforward quantification of recombinant proteins using fluorescence polarization

Scientifique ArODES

Condemi Enrico, Prim Denis, Brönnimann Rebecca, Fusco Jonathan, Crelier Simon, Mamula Steiner Olimpia, Segura Jean-Manuel

CHIMIA International Journal for Chemistry, 2016, vol. 70, no. 10, p. 731

Link zur Publikation

2013

Monitoring labeling reactions using fluorescence polarization

Scientifique ArODES

Crittin Yvan, Héritier Julien, Segura Jean-Manuel

CHIMIA International Journal for Chemistry, 2013, vol. 67, no. 10, p. 740-741

Link zur Publikation

Zusammenfassung:

Fluorescence techniques are widely applied in protein research owing to their specificity and sensitivity, but require prior fluorescent labeling. Here we show a novel approach to optimize labeling protocols by monitoring labeling reactions using fluorescence polarization: the larger molecular mass of the fluorescent protein conjugate compared to the dye alone results in an increase in fluorescence anisotropy during the reaction. Thereby, labeling of lysozyme with fluorescein isothiocyanate or carboxyfluorescein succinimidyl ester could be monitored and the influence of parameters such as the pH could be quantitatively assessed. Moreover, the impact and kinetics of side reactions such as hydrolysis were determined. This new method is rapid, easy to implement, and generically applicable.

2011

Coupling of a microfluidic mixer to a Fourier-transform infrared spectrometer for protein-conformation studies

Scientifique ArODES

Prim Denis, Crelier Simon, Segura Jean-Manuel

CHIMIA International Journal for Chemistry, 2011, vol. 65, no. 10, pp. 815-816

Link zur Publikation

Zusammenfassung:

The biological properties of a protein critically depend on its conformation, which can vary as a result of changes in conditions such as pH or following the addition of various substances. Being able to reliably assess the quality of protein structures under various conditions is therefore of crucial importance. Infrared (IR) spectroscopy of the Amide I band of proteins is a powerful method for the determination of protein conformations and further allows the analysis of continuously flowing solutions of the target molecule. Here, a commercial Fourier-transform infrared spectrometer was coupled to a microfluidic mixer to allow the on-line monitoring of protein conformation under varying conditions. The validity of the concept was demonstrated by continuously recording the variations of the IR spectrum of poly-L-lysine resulting from repetitive, pH-induced conformational changes.

Acetylcholine receptor organization in membrane domains in muscle cells

Scientifique ArODES

Piguet Joachim, Schreiter Christoph, Segura Jean-Manuel, Vogel Horst, Hovius Ruud

Journal of Biological Chemistry, 2011, vol. 286, no. 1, pp. 363-369

Link zur Publikation

Zusammenfassung:

Nicotinic acetylcholine receptors (nAChR) in muscle fibers are densely packed in the postsynaptic region at the neuromuscular junction. Rapsyn plays a central role in directing and clustering nAChR during cellular differentiation and neuromuscular junction formation; however, it has not been demonstrated whether rapsyn is the only cause of receptor immobilization. Here, we used single-molecule tracking methods to investigate nAChR mobility in plasma membranes of myoblast cells during their differentiation to myotubes in the presence and absence of rapsyn. We found that in myoblasts the majority of nAChR were immobile and that ∼20% of the receptors showed restricted diffusion in small domains of ∼50 nm. In myoblasts devoid of rapsyn, the fraction of mobile nAChR was considerably increased, accompanied by a 3-fold decrease in the immobile population of nAChR with respect to rapsyn-expressing cells. Half of the mobile receptors were confined to domains of ∼120 nm. Measurements performed in heterologously transfected HEK cells confirmed the direct immobilization of nAChR by rapsyn. However, irrespective of the presence of rapsyn, about one-third of nAChR were confined in 300-nm domains. Our results show (i) that rapsyn efficiently immobilizes nAChR independently of other postsynaptic scaffold components; (ii) nAChR is constrained in confined membrane domains independently of rapsyn; and (iii) in the presence of rapsyn, the size of these domains is strongly reduced.

Errungenschaften

Suche

Segura Jean-Manuel

Professeur-e HES Associé-e, Responsable de l'orientation Chimie analytique

Hauptkompetenzen

In vitro Diagnostics

Point-of-care diagnostics (POCT)

Immunoassays

Fluorescence

Professeur-e HES Associé-e, Responsable de l'orientation Chimie analytique