Philippe Favreau - Academia.edu (original) (raw)
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Papers by Philippe Favreau
Journal of Physiology-Paris, 1998
Nucleic Acids Research, 2012
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2013
Chemistry - A European Journal, 2013
Journal of Physiology-Paris, 1998
Chemosphere, 2016
Hexabromocyclododecane (HBCDD) is a brominated flame retardant (BFR) and major additive to polyst... more Hexabromocyclododecane (HBCDD) is a brominated flame retardant (BFR) and major additive to polystyrene foam thermal insulation that has recently been listed as a persistent organic pollutant by the Stockholm Convention. During a 2013/2014 field analytical survey, we measured HBCDD content ranging from 0.2 to 2.4% by weight in 98 polystyrene samples. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses indicated that expandable (EPS) and extruded (XPS) polystyrene foams significantly differed in the α/γ HBCDD isomer ratio, with a majority of α and γ isomers in XPS and EPS, respectively. Interestingly, this technique indicated that some recent materials did not contain HBCDD, but demonstrated bromine content when analysed with X-ray fluorescence (XRF). Further investigation by Nuclear Magnetic Resonance (NMR) was able to discriminate between the BFRs present. In addition to confirming the absence or presence of HBCDD in polystyrene samples, high-field NMR spectroscopy provided evidence of the use of brominated butadiene styrene (BBS) as copolymer in the production of polystyrene. Use of this alternative flame retardant is expected to cause fewer health and environmental concerns. Our results highlight a trend towards the use of copolymerized BFRs as an alternative to HBCDD in polystyrene foam boards. In addition to providing a rapid NMR method to identify polymeric BFR, our analytical approach is a simple method to discriminate between flame-retardants in polystyrene foam insulating materials.
Journal of Occupational and Environmental Hygiene, 2014
Field-portable X-ray fluorescence (FP-XRF) instruments are important for non-destructive, rapid a... more Field-portable X-ray fluorescence (FP-XRF) instruments are important for non-destructive, rapid and convenient measurements of lead in paint, in view of potential remediation. Using real-life paint samples, we compared measurements from three FP-XRF instruments currently used in Switzerland with laboratory measurements using inductively coupled plasma mass spectrometry after complete sample dissolution. Two FP-XRF devices that functioned by lead L shell excitation frequently underestimated the lead concentration of samples. Lack of accuracy correlated with lead depth and/or the presence of additional metal elements (Zn, Ba or Ti). A radioactive source emitter XRF that enabled the additional K shell excitation showed higher accuracy and precision, regardless of the depth of the lead layer in the sample or the presence of other elements. Inspection of samples by light and electron microscopy revealed the diversity of real-life samples, with multi-layered paints showing various depths of lead and other metals. We conclude that the most accurate measurements of lead in paint are currently obtained with instruments that provide at least sufficient energy for lead K shell excitation.
Chemistry of Materials, 1994
Journal of Physiology-Paris, 1998
Biochemistry Usa, 1999
Two novel alpha-conotoxins were purified and characterized from the venom of the fish-hunting con... more Two novel alpha-conotoxins were purified and characterized from the venom of the fish-hunting cone snail Conus consors. These peptides were identified by screening HPLC fractions of the crude venom and by binding experiments with Torpedo nicotinic acetylcholine receptor. The toxins named alpha-CnIA and alpha-CnIB exhibited sequences of 14 and 12 amino acids, respectively. The alpha-CnIA represents the main alpha-conotoxin contained in the venom, whereas alpha-CnIB is present in a relatively small amount. Chemical synthesis of alpha-CnIA was carried out using the Fmoc methodology by selective disulfide bond formation. The biological activity of the toxin was assessed in fish and mice. The alpha-CnIA inhibited the fixation of iodinated alpha-bungarotoxin to Torpedo nicotinic acetylcholine receptors with an IC50 of 0.19 microM which can be compared to the IC50 of 0.31 microM found for the previously characterized alpha-MI isolated from the piscivorous Conus magus. The synthetic alpha-CnIA blocked spontaneous and evoked synaptic potentials in frog and mouse isolated neuromuscular preparations at sub-micromolar concentrations. Solution NMR of this toxin indicated a conformational heterogeneity with the existence of different conformers in solution, at slow and intermediate exchange rates relative to the NMR chemical shift time scale, similar to that reported for alpha-GI and alpha-MI. NMR structures were calculated for the major NMR signals representing more than 80% of the population at 5 degrees C.
ABSTRACT International Patent Classification: C07K14/435 International Application Number: PCT/IB... more ABSTRACT International Patent Classification: C07K14/435 International Application Number: PCT/IB2006/003147
LC-MS has become the reference profiling technique in peptide analysis such as venomics, providin... more LC-MS has become the reference profiling technique in peptide analysis such as venomics, providing abundant valuable data [1]. Efforts have been mainly focused on the detection part while the chromatographic aspects were not thoroughly investigated. An optimized separation could provide more resolved peaks and thus, more valuable MS data. The new generation of analyzers able to acquire automatic fragmentation data with a higher acquisition rate, allows working with thinner peaks and thus higher peak capacity. Thus, there is a need for higher resolution in the LC dimension. In this study, the use of columns packed with sub-2μm particles and of a Ultra High Pressure LC (UHPLC) system were used in different chromatographic conditions. The goal was to obtain a higher peak capacity when analyzing venom of the marine snail species Conus consors and to model the separation as a function of chromatographic parameters. Theoretically, the use of smaller particles size impact extremely positiv...
International Patent Classification: C07K14/435 International Application Number: PCT/IB2006/003147
With more than 800 Conus species available worldwide, cone snail venoms appear as one of the rich... more With more than 800 Conus species available worldwide, cone snail venoms appear as one of the richest source of natural peptides that exhibit a wide array of biological activity by targeting various molecular entities. Among them, the μ-conotoxin family includes around 10 compounds whose effect consists generally in a blockade of muscle voltage-gated Na channel conductance. We purified a new conotoxin (μ-CnIIIC) from the venom of Conus consors collected in Chesterfield Island (New Caledonia), determined its amino acid sequence (consisting of 22 amino acids folded by 3 disulfide bridges and sharing homology with known μ-conotoxins), and performed its solid-phase synthesis. Synthetic μ-CnIIIC was then used for different biological assays. μ-CnIIIC decreased mouse hemidiaphragm contraction, the effective concentration producing half maximal inhibition (EC50) being 0.15 μM. Comparison of μ-CnIIIC effect to other μ-conotoxins on mouse extensor digitorum longus muscle contraction showed th...
Journal of Physiology-Paris, 1998
Nucleic Acids Research, 2012
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2013
Chemistry - A European Journal, 2013
Journal of Physiology-Paris, 1998
Chemosphere, 2016
Hexabromocyclododecane (HBCDD) is a brominated flame retardant (BFR) and major additive to polyst... more Hexabromocyclododecane (HBCDD) is a brominated flame retardant (BFR) and major additive to polystyrene foam thermal insulation that has recently been listed as a persistent organic pollutant by the Stockholm Convention. During a 2013/2014 field analytical survey, we measured HBCDD content ranging from 0.2 to 2.4% by weight in 98 polystyrene samples. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses indicated that expandable (EPS) and extruded (XPS) polystyrene foams significantly differed in the α/γ HBCDD isomer ratio, with a majority of α and γ isomers in XPS and EPS, respectively. Interestingly, this technique indicated that some recent materials did not contain HBCDD, but demonstrated bromine content when analysed with X-ray fluorescence (XRF). Further investigation by Nuclear Magnetic Resonance (NMR) was able to discriminate between the BFRs present. In addition to confirming the absence or presence of HBCDD in polystyrene samples, high-field NMR spectroscopy provided evidence of the use of brominated butadiene styrene (BBS) as copolymer in the production of polystyrene. Use of this alternative flame retardant is expected to cause fewer health and environmental concerns. Our results highlight a trend towards the use of copolymerized BFRs as an alternative to HBCDD in polystyrene foam boards. In addition to providing a rapid NMR method to identify polymeric BFR, our analytical approach is a simple method to discriminate between flame-retardants in polystyrene foam insulating materials.
Journal of Occupational and Environmental Hygiene, 2014
Field-portable X-ray fluorescence (FP-XRF) instruments are important for non-destructive, rapid a... more Field-portable X-ray fluorescence (FP-XRF) instruments are important for non-destructive, rapid and convenient measurements of lead in paint, in view of potential remediation. Using real-life paint samples, we compared measurements from three FP-XRF instruments currently used in Switzerland with laboratory measurements using inductively coupled plasma mass spectrometry after complete sample dissolution. Two FP-XRF devices that functioned by lead L shell excitation frequently underestimated the lead concentration of samples. Lack of accuracy correlated with lead depth and/or the presence of additional metal elements (Zn, Ba or Ti). A radioactive source emitter XRF that enabled the additional K shell excitation showed higher accuracy and precision, regardless of the depth of the lead layer in the sample or the presence of other elements. Inspection of samples by light and electron microscopy revealed the diversity of real-life samples, with multi-layered paints showing various depths of lead and other metals. We conclude that the most accurate measurements of lead in paint are currently obtained with instruments that provide at least sufficient energy for lead K shell excitation.
Chemistry of Materials, 1994
Journal of Physiology-Paris, 1998
Biochemistry Usa, 1999
Two novel alpha-conotoxins were purified and characterized from the venom of the fish-hunting con... more Two novel alpha-conotoxins were purified and characterized from the venom of the fish-hunting cone snail Conus consors. These peptides were identified by screening HPLC fractions of the crude venom and by binding experiments with Torpedo nicotinic acetylcholine receptor. The toxins named alpha-CnIA and alpha-CnIB exhibited sequences of 14 and 12 amino acids, respectively. The alpha-CnIA represents the main alpha-conotoxin contained in the venom, whereas alpha-CnIB is present in a relatively small amount. Chemical synthesis of alpha-CnIA was carried out using the Fmoc methodology by selective disulfide bond formation. The biological activity of the toxin was assessed in fish and mice. The alpha-CnIA inhibited the fixation of iodinated alpha-bungarotoxin to Torpedo nicotinic acetylcholine receptors with an IC50 of 0.19 microM which can be compared to the IC50 of 0.31 microM found for the previously characterized alpha-MI isolated from the piscivorous Conus magus. The synthetic alpha-CnIA blocked spontaneous and evoked synaptic potentials in frog and mouse isolated neuromuscular preparations at sub-micromolar concentrations. Solution NMR of this toxin indicated a conformational heterogeneity with the existence of different conformers in solution, at slow and intermediate exchange rates relative to the NMR chemical shift time scale, similar to that reported for alpha-GI and alpha-MI. NMR structures were calculated for the major NMR signals representing more than 80% of the population at 5 degrees C.
ABSTRACT International Patent Classification: C07K14/435 International Application Number: PCT/IB... more ABSTRACT International Patent Classification: C07K14/435 International Application Number: PCT/IB2006/003147
LC-MS has become the reference profiling technique in peptide analysis such as venomics, providin... more LC-MS has become the reference profiling technique in peptide analysis such as venomics, providing abundant valuable data [1]. Efforts have been mainly focused on the detection part while the chromatographic aspects were not thoroughly investigated. An optimized separation could provide more resolved peaks and thus, more valuable MS data. The new generation of analyzers able to acquire automatic fragmentation data with a higher acquisition rate, allows working with thinner peaks and thus higher peak capacity. Thus, there is a need for higher resolution in the LC dimension. In this study, the use of columns packed with sub-2μm particles and of a Ultra High Pressure LC (UHPLC) system were used in different chromatographic conditions. The goal was to obtain a higher peak capacity when analyzing venom of the marine snail species Conus consors and to model the separation as a function of chromatographic parameters. Theoretically, the use of smaller particles size impact extremely positiv...
International Patent Classification: C07K14/435 International Application Number: PCT/IB2006/003147
With more than 800 Conus species available worldwide, cone snail venoms appear as one of the rich... more With more than 800 Conus species available worldwide, cone snail venoms appear as one of the richest source of natural peptides that exhibit a wide array of biological activity by targeting various molecular entities. Among them, the μ-conotoxin family includes around 10 compounds whose effect consists generally in a blockade of muscle voltage-gated Na channel conductance. We purified a new conotoxin (μ-CnIIIC) from the venom of Conus consors collected in Chesterfield Island (New Caledonia), determined its amino acid sequence (consisting of 22 amino acids folded by 3 disulfide bridges and sharing homology with known μ-conotoxins), and performed its solid-phase synthesis. Synthetic μ-CnIIIC was then used for different biological assays. μ-CnIIIC decreased mouse hemidiaphragm contraction, the effective concentration producing half maximal inhibition (EC50) being 0.15 μM. Comparison of μ-CnIIIC effect to other μ-conotoxins on mouse extensor digitorum longus muscle contraction showed th...