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1. Pre- and Postnatal Dietary Exposure to a Pesticide Cocktail Disrupts Ovarian Functions in 8-Week-Old Female Mice

Author

Léonie Dopavogui, Florence Cadoret, Gaspard Loison, Sara El Fouikar, François-Xavier Frenois, Frank Giton, Sandrine Ellero-Simatos, Frédéric Lasserre, Arnaud Polizzi, Clémence Rives, Nicolas Loiseau, Roger D. Léandri, Nicolas Gatimel, Laurence Gamet-Payrastre, Toxicologie Intégrative & Métabolisme (ToxAlim-TIM), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), CHU Toulouse [Toulouse], Développement Embryonnaire, Fertilité et Environnement (DEFE), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM), Exposition, Perturbation Endocrino-métabolique et Reproduction (ToxAlim-EXPER), Institut Universitaire du Cancer de Toulouse - Oncopole (IUCT Oncopole - UMR 1037), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-CHU Toulouse [Toulouse]-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Mondor de Recherche Biomédicale (IMRB), Institut National de la Santé et de la Recherche Médicale (INSERM)-IFR10-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), L.D. was supported by a Ph.D. grant from INRAE (Animal Health Department). This work was supported by a grant from the Ministry for Agriculture and Food and the Ministry for an Ecological and Solidary Transition, with the financial support of the French Biodiversity Agency (GepeTho), by ANR France (Syneract), and by Région Occitanie. This work also received funding from Agence de la Biomédecine (AOR 2019).This paper benefited from the Imag’IN Platform of the Institut Universitaire du Cancer from April 2019 to August 2021 https://www.imagin-labs.net/imagin_v2/index.php? lang=EN (last accessed on 5 June 2022). We thank X. Blanc from INRAe SAAJ (Jouy-en-Josas) for his technical support for pellet preparation., ANR-18-CE34-0009,SYNERACT,Activation synergique de recepteurs nucléaires(2018), Centre Hospitalier Universitaire de Toulouse (CHU Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre Hospitalier Universitaire de Toulouse (CHU Toulouse)-Institut National de la Santé et de la Recherche Médicale (INSERM), LESUR, Hélène, and APPEL À PROJETS GÉNÉRIQUE 2018 - Activation synergique de recepteurs nucléaires - - SYNERACT2018 - ANR-18-CE34-0009 - AAPG2018 - VALID

Subjects
pesticide, folliculogenesis, ovary, endocrine disruption, progesterone, [SDV]Life Sciences [q-bio], Organic Chemistry, Pesticide Residues, General Medicine, Catalysis, Computer Science Applications, [SDV] Life Sciences [q-bio], Inorganic Chemistry, Dietary Exposure, Mice, Fruit, Animals, Female, Chlorpyrifos, Physical and Theoretical Chemistry, Pesticides, Molecular Biology, Spectroscopy
Abstract

International audience; Female infertility has a multifactorial origin, and exposure to contaminants, including pesticides, with endocrine-disrupting properties is considered to be involved in this reproductive disorder, especially when it occurs during early life. Pesticides are present in various facets of the environment, and consumers are exposed to a combination of multiple pesticide residues through food intake. The consequences of such exposure with respect to female fertility are not well known. Therefore, we aimed to assess the impact of pre- and postnatal dietary exposure to a pesticide mixture on folliculogenesis, a crucial process in female reproduction. Mice were exposed to the acceptable daily intake levels of six pesticides in a mixture (boscalid, captan, chlorpyrifos, thiacloprid, thiophanate and ziram) from foetal development until 8 weeks old. Female offspring presented with decreased body weight at weaning, which was maintained at 8 weeks old. This was accompanied by an abnormal ovarian ultrastructure, a drastic decrease in the number of corpora lutea and progesterone levels and an increase in ovary cell proliferation. In conclusion, this study shows that this pesticide mixture that can be commonly found in fruits in Europe, causing endocrine disruption in female mice with pre- and postnatal exposure by disturbing folliculogenesis, mainly in the luteinisation process.

Published
2022
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2. A dedicated robust instrument for water vapor generation at low humidity for use with a laser water isotope analyzer in cold and dry polar regions

Author

C. Leroy-Dos Santos, M. Casado, F. Prié, O. Jossoud, E. Kerstel, M. Farradèche, S. Kassi, E. Fourré, A. Landais, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Agence Nationale de la Recherche, ANR Institut Polaire Français Paul Emile Victor, IPEV: 1110, 1205 Prince Albert II of Monaco Foundation: 2487, Financial support. This research has been supported by the Prince Albert II of Monaco Foundation: 2487, Acknowledgements. The development presented in this paper was largely inspired by the initial PhD work of Janek Landsberg, which we gratefully acknowledge here. The research leading to these results has received funding from the Prince Albert II of Monaco Foundation 'ANTARCTIC-SNOW' program, the ANR 'EAIIST' project and the ADELISE 'CNRS-LEFE' program. The deployment of this instrument in the field was made possible by the logistic support from the 'NIVO2' and ADELISE 'IPEV' programs. We thank the two reviewers for their useful comments which greatly improved the article., ANR-16-CE01-0011,EAIIST,Projet International d'exploration de la calotte polaire de l'Antarctique de l'Est(2016), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Atmospheric Science, Spectrum analyzer, 010504 meteorology & atmospheric sciences, δ18O, lcsh:TA715-787, 010401 analytical chemistry, lcsh:Earthwork. Foundations, Humidity, Atmospheric sciences, Laser, 01 natural sciences, 0104 chemical sciences, law.invention, lcsh:Environmental engineering, 13. Climate action, law, Environmental science, Polar, Precipitation, lcsh:TA170-171, Spectroscopy, Water vapor, 0105 earth and related environmental sciences
Abstract

Obtaining precise continuous measurements of water vapor isotopic composition in dry places (polar or high-altitude regions) is an important challenge. The current limitation is the strong influence of humidity on the measured water isotopic composition by laser spectroscopy instruments for low humidity levels (below 3000 ppmv). This problem is addressed by determining the relationships between humidity and measured δ18O and δD of known water standards. Here, we present the development of a robust field instrument able to generate water vapor, down to 70 ppmv, at very stable humidity levels (average 1σ lower than 10 ppmv). This instrument, operated by a Raspberry interface, can be coupled to a commercial laser spectroscopy instrument. We checked the stability of the system as well as its accuracy when expressing the measured isotopic composition of water vapor on the VSMOW–SLAP (Vienna Standard Mean Ocean Water – Standard Light Antarctic Precipitation) scale. It proved to be highly stable during autonomous operation over more than 1 year at the East Antarctic Concordia and Dumont d'Urville stations.

Published
2021

5. Tumour heterogeneity: the key advantages of single-cell analysis

Author

Francois Lamoureux, Marta Tellez-Gabriel, Benjamin Ory, Dominique Heymann, Marie-Françoise Heymann, Laboratorio Hematologia Oncologica y de Transplantes [Barcelona, Spain], Institut Investigacions Biomèdiques (IBB) Sant Pau [Barcelona, Spain]-Hospital de la Santa Creu i Sant Pau, Equipe LIGUE Nationale Contre le Cancer 2012, Physiopathologie des Adaptations Nutritionnelles (PhAN), Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Department of Oncology and Metabolism [Sheffield, UK], The University of Sheffield [Sheffield, U.K.], European Associated Laboratory [Sheffield, UK] (Sarcoma Research Unit), This paper was written as a part of a research project which received funding from the Seventh Framework Programme ([FP7/2007-2013]) under grant agreement n 264817—BONE-NET. This work was supported by the Bone Cancer Research Trust (UK, research project number 144681)., European Project: 264817,EC:FP7:PEOPLE,FP7-PEOPLE-2010-ITN,BONE-NET(2011), Heymann, Dominique, and European Training Network on Cancer-Induced Bone Diseases - BONE-NET - - EC:FP7:PEOPLE2011-02-01 - 2015-01-31 - 264817 - VALID

Subjects
0301 basic medicine, Tumour heterogeneity, circulating tumour cells, [SDV.CAN]Life Sciences [q-bio]/Cancer, Disease, Review, Biology, Bioinformatics, Catalysis, lcsh:Chemistry, Inorganic Chemistry, 03 medical and health sciences, Genetic Heterogeneity, [SDV.MHEP.PED] Life Sciences [q-bio]/Human health and pathology/Pediatrics, Single-cell analysis, [SDV.CAN] Life Sciences [q-bio]/Cancer, single cells, Neoplasms, Gene expression, Biopsy, medicine, Humans, Epigenetics, Physical and Theoretical Chemistry, Neoplasm Metastasis, lcsh:QH301-705.5, Molecular Biology, Spectroscopy, [SDV.MHEP.EM] Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism, [SDV.MHEP.RSOA] Life Sciences [q-bio]/Human health and pathology/Rhumatology and musculoskeletal system, [SDV.MHEP.PED]Life Sciences [q-bio]/Human health and pathology/Pediatrics, medicine.diagnostic_test, Organic Chemistry, General Medicine, [SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism, Neoplastic Cells, Circulating, Phenotype, 3. Good health, Computer Science Applications, 030104 developmental biology, lcsh:Biology (General), lcsh:QD1-999, [SDV.MHEP.RSOA]Life Sciences [q-bio]/Human health and pathology/Rhumatology and musculoskeletal system, Cancer cell, Cancer research, Single-Cell Analysis, heterogeneity
Abstract

International audience; Tumour heterogeneity refers to the fact that different tumour cells can show distinct morphological and phenotypic profiles, including cellular morphology, gene expression, metabolism, motility, proliferation, and metastatic potential. This phenomenon occurs both between tumours (inter-tumour heterogeneity) and within tumours (intra-tumour heterogeneity), and it is caused by genetic and non-genetic factors. The heterogeneity of cancer cells introduces significant challenges in using molecular prognostic markers as well as for classifying patients that might benefit from specific therapies. Thus, research efforts for characterizing heterogeneity would be useful for a better understanding of the causes and progression of disease. It has been suggested that the study of heterogeneity within Circulating Tumour Cells (CTCs) could also reflect the full spectrum of mutations of the disease more accurately than a single biopsy of a primary or metastatic tumour. In the last years many high throughput methodologies have raised for the study of heterogeneity at different levels (i.e.: RNA, DNA, protein, epigenetic events). The aim of the current review is to stress clinical implications of tumour heterogeneity, as well as current available methodologies for their study with a specific attention to those able to assess heterogeneity at the single cell level.

Published
2016

6. Narrow Linewidth Excitonic Emission in Organic-Inorganic Lead Iodide Perovskite Single Crystals

Author

Diab, Hiba, Trippé-Allard, Gaëlle, Lédée, Ferdinand, Jemli, Khaoula, Vilar, Christèle, Bouchez, Guillaume, Jacques, Vincent L.R., Tejeda, Antonio, Even, Jacky, Lauret, Jean-Sébastien, Deleporte, Emmanuelle, Garrot, Damien, Laboratoire Aimé Cotton (LAC), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), École normale supérieure - Cachan (ENS Cachan)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Groupe d'Etude de la Matière Condensée (GEMAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Photonique Quantique et Moléculaire (LPQM), École normale supérieure - Cachan (ENS Cachan)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the grant agreement No 687008. The information and views set out in this paper are those of the author(s) and do not necessarily reflect the official opinion of the European Union. Neither the European Union institutions and bodies nor any person acting on their behalf may be held responsible for the use which may be made of the information contained herein. J.S. Lauret is ajunior member of the Institut Universitaire de France., Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École normale supérieure - Cachan (ENS Cachan), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Photoluminescence, Exciton, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Laser linewidth, Condensed Matter::Materials Science, Condensed Matter::Superconductivity, General Materials Science, Physical and Theoretical Chemistry, Thin film, Spectroscopy, Perovskite (structure), business.industry, Condensed Matter::Other, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Full width at half maximum, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, Crystallite, 0210 nano-technology, business
Abstract

International audience; Hybrid perovskite thin films have demonstrated impressive performance for solar energy conversion and optoelectronic applications. However, further progress will benefit from a better knowledge of the intrinsic photophysics of materials. Here, the temperature-dependent emission properties of CH3NH3PbI3 single crystals are investigated and compared to those of thin polycrystalline films by means of steady-state and time-resolved photoluminescence spectroscopy. Single crystals photoluminescence present a sharp excitonic emission at high energy, with full width at half maximum of only 5 meV, assigned to free excitonic recombination. We highlight a strong thermal broadening of the free excitonic emission, due to exciton–LO-phonon coupling. The emission turned to be very short-lived with a subnanosecond dynamics, mainly induced by the fast trapping of the excitons. The free excitonic emission is completely absent of the thin film spectra, which are dominated by trap state bands.

Published
2016

7. Introduction of Soft X-Ray Spectromicroscopy as an Advanced Technique for Plant Biopolymers Research

Author

Rachid Lahlali, Colleen R. Christensen, Cédric Gaillard, Lisa M. Blair, S. Shea Miller, Vijayan Perumal, Adam P. Hitchcock, Chithra Karunakaran, Canadian Light Source, University of Saskatchewan [Saskatoon] (U of S), National Research Council of Canada (NRC), Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de la Recherche Agronomique (INRA), Canadian Food Inspection Agency (CFIA), Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food [Ottawa] (AAFC), McMaster University, and The research described in this paper was performed at the Canadian Light Source Inc., and the Advanced Light Source. The Canadian Light Source Inc. is supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), National Research Council Canada (NRC), Canadian Institutes of Health Research (CIHR), and the University of Saskatchewan. The Advanced Light Source is supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098.

Subjects
plant stem, Absorption spectroscopy, Lens culinaris, lcsh:Medicine, lignin, soft X ray absorption spectromicroscopy, Infrared spectroscopy, Nanotechnology, image display, engineering.material, lentil, Biopolymers, sensitivity analysis, biopolymer, process optimization, Spectroscopy, Fourier Transform Infrared, [SDV.IDA]Life Sciences [q-bio]/Food engineering, Microscopy, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, lcsh:Science, infrared spectroscopy, intermethod comparison, Absorption (electromagnetic radiation), Spectroscopy, plant cell, X-ray absorption spectroscopy, Multidisciplinary, Plant Stems, lcsh:R, Resolution (electron density), hemicellulose, Plants, cellulose, arabinoxylan, X-Ray Absorption Spectroscopy, phase transition, X ray absorption spectroscopy, microscopy, engineering, polygalacturonic acid, Lens Plant, lcsh:Q, Biopolymer, Research Article, amino acid substitution
Abstract

International audience; Soft X-ray absorption spectroscopy coupled with nano-scale microscopy has been widely used in material science, environmental science, and physical sciences. In this work, the advantages of soft X-ray absorption spectromicroscopy for plant biopolymer research were demonstrated by determining the chemical sensitivity of the technique to identify common plant biopolymers and to map the distributions of biopolymers in plant samples. The chemical sensitivity of soft X-ray spectroscopy to study biopolymers was determined by recording the spectra of common plant biopolymers using soft X-ray and Fourier Transform mid Infrared (FT-IR) spectroscopy techniques. The soft X-ray spectra of lignin, cellulose, and polygalacturonic acid have distinct spectral features. However, there were no distinct differences between cellulose and hemicellulose spectra. Mid infrared spectra of all biopolymers were unique and there were differences between the spectra of water soluble and insoluble xylans. The advantage of nano-scale spatial resolution exploited using soft X-ray spectromicroscopy for plant biopolymer research was demonstrated by mapping plant cell wall biopolymers in a lentil stem section and compared with the FT-IR spectromicroscopy data from the same sample. The soft X-ray spectromicroscopy enables mapping of biopolymers at the sub-cellular (similar to 30 nm) resolution whereas, the limited spatial resolution in the micron scale range in the FT-IR spectromicroscopy made it difficult to identify the localized distribution of biopolymers. The advantages and limitations of soft X-ray and FT-IR spectromicroscopy techniques for biopolymer research are also discussed.

Published
2015

8. Modification of the Elastic Constants of a Peptide-Decorated Lamellar Phase

Author

Marcel Waks, John Kauffman, Wladimir Urbach, Nicolas Tsapis, Alain Chaffotte, John Everett, Peter Kahn, Dror E. Warschawski, R. Ober, Laboratoire de Physique de la Matière Condensée (LPMC), Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Biochimie cellulaire, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de biologie physico-chimique des protéines membranaires (LBPC-PM (UMR_7099)), Institut de biologie physico-chimique (IBPC (FR_550)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Rutgers University System (Rutgers), Laboratoire d'Imagerie Paramétrique (LIP), Université Pierre et Marie Curie - Paris 6 (UPMC)-IFR58-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Statistique de l'ENS (LPS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), N.T. was supported by a 'Société de Secours des Amis des Sciences' fellowship. P.K. acknowledges the support of the New Jersey Agriculture Experiment Station (Paper D-01405-1-01)., Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Surfactants, [SDV]Life Sciences [q-bio], Peptide, 02 engineering and technology, Decane, Peptides and proteins, 01 natural sciences, Stiffness, chemistry.chemical_compound, Lamellar phase, 0103 physical sciences, Electrochemistry, [CHIM]Chemical Sciences, General Materials Science, Vesicles, 010306 general physics, Spectroscopy, chemistry.chemical_classification, Bilayer, Vesicle, Surfaces and Interfaces, Lipid bilayer mechanics, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Crystallography, chemistry, [SDE]Environmental Sciences, 0210 nano-technology, Thickness
Abstract

International audience; We have investigated the effect of the insertion of a triblock peptide (hydrophobic−hydrophilic−hydrophobic) in a nonionic lamellar phase composed of C12E4, decane, and water, stabilized by bilayer thermal fluctuations. Circular dichroism shows the peptide to be unordered in water, whereas its hydrophilic part is rigid and organized in an α-helix in the presence of surfactant bilayers. Surface tension measurements prove that the peptide is located at the hydrophobic−hydrophilic interface. Together with spectrofluorometry, these experiments suggest that the peptide lies on the bilayer surface. The Caillé parameter, η, of the lamellar phase, obtained by SAXS experiments, decreases with peptide concentration. This decrease has been interpreted as an increase of the bilayer effective thickness induced by the peptide and is well fitted by a recent model. The bilayer bending rigidity κ increases linearly with peptide concentration, up to two times the rigidity of a bare bilayer with mole ratio of peptide to surfactant as low as 5.2 × 10-4. The smectic compressibility modulus, B̄, decreases, implying that the peptide presence softens interactions between bilayers.

Published
2002