Publications

2005

• Retinal isomerization dynamics in dry bacteriorhodopsin films
  
  • Colonna Anne
  • Groma Geza I.
  • Vos Marten H.
  Chemical Physics Letters, Elsevier, 2005, 415 (1-3), pp.69-73. The primary photoprocesses in neutral and acid forms of oriented dried bacteriorhodopsin films were investigated by femtosecond absorption spectroscopy. The excitation energy dependence of the signals was used to distinguish photochemistry from processes involving photophysics of photocycle intermediates. Both the kinetics and the quantum yield of all-trans excited state decay by retinal photoisomerization and subsequent J → K transition were found to be very similar as in hydrated environments. Therefore, unlike slower photocycle phases, communication of the retinal with the environment does not play a role in retinal isomerization. Our results are important for understanding recent nonlinear optical applications of such films. (10.1016/j.cplett.2005.08.132)
  DOI : 10.1016/j.cplett.2005.08.132
• Dynamique ultrarapide au sein des protéines vue par spectroscopie optique: interactions hémoprotéines-ligands
  
  • Vos Marten H.
  , 2005.
• 11th Congress of the European Society for Photobiology
  
  • Dartigalongue Thibault
  • Hache François
  , 2005.
• Fourier transform measurement of two-photon excitation spectra: applications to microscopy and optimal control
  
  • Ogilvie Jennifer P.
  • Kubarych Kevin J.
  • Alexandrou Antigoni
  • Joffre Manuel
  Optics Letters, Optical Society of America - OSA Publishing, 2005, 30, pp.911. We report a novel Fourier transform method for measuring two-photon excitation spectra. We demonstrate this method using simple dye molecules and discuss its applications in two-photon fluorescence microscopy and optimal control. This method facilitates an intuitive interpretation of recent control experiments in terms of tuning the nonlinear spectrum of the exciting laser source.
• Chiroptical effects in the second harmonic signal of collagens I and IV
  
  • Pena Ana-Maria
  • Boulesteix Thierry
  • Dartigalongue Thibault
  • Schanne-Klein Marie-Claire
  Journal of the American Chemical Society, American Chemical Society, 2005, 127 (29), pp.10314. We performed polarization-resolved surface second harmonic generation (SHG) experiments on thin films of collagen I and IV molecules, as well as conventional CD measurements. We found that collagen IV presents little CD and no SHG optical activity, whereas collagen I exhibits large chiroptical effects involving both one-electron and excitonic coupling mechanisms. We estimated that these chiral components enhance the SHG signal from fibrillar collagen in biological tissues by typically a factor of 2. By comparing the distinct behaviors of collagens I and IV in SHG microscopy and in surface SHG experiments, we concluded that SHG microscopy is a sensitive probe of the micrometer-scale structural organization of collagen in biological tissues. Cop. 2005 American Chemical Society. (10.1021/ja0520969)
  DOI : 10.1021/ja0520969
• Unstained Drosophila embryo development analysed by velocimetric third harmonic generation microscopy
  
  • Débarre Delphine
  • Supatto Willy
  • Farge Emmanuel
  • Moulia Bruno B.
  • Schanne-Klein Marie-Claire
  • Beaurepaire Emmanuel
  , 2005.
• Sensibilité structurale et sources de contraste en microscopie par génération de troisième harmonique (THG) appliquée à la biologie
  
  • Débarre Delphine
  • Supatto Willy
  • Pena Ana-Maria
  • Fabre Aude
  • Tordjmann T.
  • Combettes Laurent
  • Schanne-Klein Marie-Claire
  • Beaurepaire Emmanuel
  , 2005.
• The temperature dependence of the ultrafast electron transfer in cytochrome c oxidase
  
  • Jasaitis Audrius
  • Rappaport Fabrice
  • Pilet Eric
  • Vos Marten H.
  , 2005.
• Nonlinear optical spectroscopy of chiral molecules
  
  • Hache François
  , 2005.
• Electrical activity alterations induced by chronic absorption of lindane (gamma-hexachlorocyclohexane) trace concentrations in adult rat heart
  
  • Sauviat Martin-Pierre
  • Bouvet Suzanne
  • Godeau Gaston
  • Pages Nicole
  Canadian Journal of Physiology and Pharmacology, NRC Research Press, 2005, 83 (3), pp.243. The heart of adult rat offspring, born to mothers treated with trace concentrations of lindane (0.5 to 2 ppb) through a beverage and to mothers chronically treated with lindane (CL-T) with the same trace concentration, also through a beverage, during lactation and growth has a round shape and accumulates lindane. The left ventricle (LV) presents a hypertrophied area, atrophied papillary muscles, and unorganized collagen bundles and layers. These observations led us to study the electrical activity of their left ventricle papillary muscles (LVPM) by recording action potential using intracellular microelectrodes. CL-T shortened LVPM action potential duration (APD): 1 ppb shortened the plateau; 2 ppb shortened the plateau and the slow repolarizing phase. In CL-T (2 ppb) and untreated groups, low temperature (22 degrees C) decreased the resting potential and prolonged APD. TEA (tetraethylammonium; 1-2 mmol/L) partially lengthened CL-T (2 ppb lindane) APD. Quinidine (0.2 mmol/L) and E-4031 (10 nmol/L) prolonged CL-T APD, suggesting that the rapid delayed outward K+ current (I-Kr) was increased. Our results indicate the silent effects of chronic exposure to trace concentrations of lindane on the morphological and electrical activity of heart muscle. They demonstrate that chronic lindane treatment of female rats alters the tissue integrity and electrical activity in the LV of their offspring. (10.1139/Y04-132)
  DOI : 10.1139/Y04-132