Professeur des Universités, Sorbonne Université
Responsable du pôle de Chimie Physique et Biologique de la Matière Vivante
PASTEUR, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS
24 rue Lhomond, 75005 Paris, France
Email: Ludovic.Jullien@ens.psl.eu or Ludovic.Jullien@sorbonne-universite.fr
Phone: +33 144323333
Office: E142c
Home page: https://ludovicjullien.org/
Publications
2012 |
Energy propagation through a protometabolism leading to the local emergence of singular stationary concentration profiles Article de journal M Emond; T Le Saux; J -F Allemand; P Pelupessy; R Plasson; L Jullien Chemistry - A European Journal, 18 (45), p. 14375–14383, 2012. @article{Emond:2012, title = {Energy propagation through a protometabolism leading to the local emergence of singular stationary concentration profiles}, author = {M Emond and T Le Saux and J -F Allemand and P Pelupessy and R Plasson and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84868034869&doi=10.1002%2fchem.201201974&partnerID=40&md5=de25aef0cd9970e53e4c8d604267fd96}, doi = {10.1002/chem.201201974}, year = {2012}, date = {2012-01-01}, journal = {Chemistry - A European Journal}, volume = {18}, number = {45}, pages = {14375--14383}, abstract = {Living systems rely on chains of energy transfer from an energy source to maintain their metabolism. This task requires functionally identified components and organizations. However, propagation of a sustained energy flux through a cascade of reaction cycles has never been reproduced at a steady state in a simple chemical system. By using energy patterning and a diffusing hub reactant, we achieved the transfer of energy through an abiotic protometabolism. Patterned illumination was applied to a liquid solution of a reversible photoacid. It resulted in the local onset of a proton pump, which subsequently drove an extended reaction-diffusion cycle that involved pH-sensitive reactants. Thus, light has been used for locally setting out of chemical equilibrium a reaction involving "blind" reactants. The spontaneous onset of an energy-transfer chain notably drives the local generation of singular dissipative chemical structures; continuous matter fluxes are dynamically maintained at boundaries between spatially and chemically segregated zones, in the absence of any membrane or predetermined material structure. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Living systems rely on chains of energy transfer from an energy source to maintain their metabolism. This task requires functionally identified components and organizations. However, propagation of a sustained energy flux through a cascade of reaction cycles has never been reproduced at a steady state in a simple chemical system. By using energy patterning and a diffusing hub reactant, we achieved the transfer of energy through an abiotic protometabolism. Patterned illumination was applied to a liquid solution of a reversible photoacid. It resulted in the local onset of a proton pump, which subsequently drove an extended reaction-diffusion cycle that involved pH-sensitive reactants. Thus, light has been used for locally setting out of chemical equilibrium a reaction involving "blind" reactants. The spontaneous onset of an energy-transfer chain notably drives the local generation of singular dissipative chemical structures; continuous matter fluxes are dynamically maintained at boundaries between spatially and chemically segregated zones, in the absence of any membrane or predetermined material structure. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Unfolding of cytochrome c upon interaction with azobenzene-modified copolymers Article de journal J Sun; J Ruchmann; A Pallier; L Jullien; M Desmadril; C Tribet Biomacromolecules, 13 (11), p. 3736–3746, 2012. @article{Sun:2012, title = {Unfolding of cytochrome c upon interaction with azobenzene-modified copolymers}, author = {J Sun and J Ruchmann and A Pallier and L Jullien and M Desmadril and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869024546&doi=10.1021%2fbm301200p&partnerID=40&md5=6a3192fce387a1fce6cb3df6a36f2c5d}, doi = {10.1021/bm301200p}, year = {2012}, date = {2012-01-01}, journal = {Biomacromolecules}, volume = {13}, number = {11}, pages = {3736--3746}, abstract = {Hydrophilic or amphiphilic macromolecules are common organic matrices used to encapsulate and protect fragile drugs such as proteins. Polymer cargoes are in addition designed for remote control of protein delivery, upon imparting the macromolecules with stimuli-responsive properties, such as light-triggered polarity switches. The effect of interaction between polymers and proteins on the stability of the proteins is, however, rarely investigated. Here we studied the unfolding/folding equilibrium of cytochrome c (cyt c) under its oxidized or reduced forms, in the presence of various amphiphilic copolymers (by circular dichroism and intrinsic fluorescence measurements). As models of stimuli-responsive amphiphilic chains, we considered poly(acrylic acid) derivatives, modified to contain hydrophobic, light-responsive azobenzene moieties. These copolymers are, thus, capable to develop both ionic (under their sodium forms at pH > 8) and hydrophobic associations with the basic protein cyt c (isoelectric point of 10.0). In aqueous buffer upon increasing urea concentrations, cyt c underwent unfolding, at [urea] of 9-10 M, which was analyzed under the framework of the equilibrium between two states (native-unfolded). In the presence of polymers, the native folding of cyt c was preserved at low concentrations of urea (typically <4M). However, the presence of polymers facilitated unfolding, which occurred at urea concentrations lowered by 2-4 M as compared to unfolding in the absence of polymers (polymer/cyt c ratio of 1:1 g/g). The predominant contribution of coulombic interactions was shown by both the lack of significant impact of the amount of (neutral) azobenzene moieties in the copolymers and the disappearance of destabilization at ionic strength higher than 150 mM. In addition, stability was similar to that of an isolated cyt c, in the presence of a neutral chain bearing acryloyl(oligoethyleneoxide) units instead of the ionized sodium acrylate moieties. DSC measurements showed that in the presence of polymers, cyt c is thermally unfolded in aqueous buffer at temperatures lowered by >20 °C as compared to thermal unfolding in the absence of polymers. Upon exposure to UV light, properties of the polymers chains were perturbed in situ, upon cis/trans isomerization of the azobenzene groups. In polymers displaying a photoresponsive polarity and hydrophobicity switch (conventional azobenzene), the stability of cyt c was not affected by the exposure to light. In contrast, when photoionization occurred (using an hydroxyl-azobenzene whose pKa can be photoshifted), unfolding was initiated upon exposure to light. Altogether, these results show that coulombic binding is a predominant driving force that facilitates unfolding in water/urea solutions. In regard to the design of light-responsive systems for protein handling and control of folding, we conclude that remote control of the coulombic interaction upon photoionization of chromophores can be more efficient than the more conventional photomodulation of polarity. © 2012 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hydrophilic or amphiphilic macromolecules are common organic matrices used to encapsulate and protect fragile drugs such as proteins. Polymer cargoes are in addition designed for remote control of protein delivery, upon imparting the macromolecules with stimuli-responsive properties, such as light-triggered polarity switches. The effect of interaction between polymers and proteins on the stability of the proteins is, however, rarely investigated. Here we studied the unfolding/folding equilibrium of cytochrome c (cyt c) under its oxidized or reduced forms, in the presence of various amphiphilic copolymers (by circular dichroism and intrinsic fluorescence measurements). As models of stimuli-responsive amphiphilic chains, we considered poly(acrylic acid) derivatives, modified to contain hydrophobic, light-responsive azobenzene moieties. These copolymers are, thus, capable to develop both ionic (under their sodium forms at pH > 8) and hydrophobic associations with the basic protein cyt c (isoelectric point of 10.0). In aqueous buffer upon increasing urea concentrations, cyt c underwent unfolding, at [urea] of 9-10 M, which was analyzed under the framework of the equilibrium between two states (native-unfolded). In the presence of polymers, the native folding of cyt c was preserved at low concentrations of urea (typically <4M). However, the presence of polymers facilitated unfolding, which occurred at urea concentrations lowered by 2-4 M as compared to unfolding in the absence of polymers (polymer/cyt c ratio of 1:1 g/g). The predominant contribution of coulombic interactions was shown by both the lack of significant impact of the amount of (neutral) azobenzene moieties in the copolymers and the disappearance of destabilization at ionic strength higher than 150 mM. In addition, stability was similar to that of an isolated cyt c, in the presence of a neutral chain bearing acryloyl(oligoethyleneoxide) units instead of the ionized sodium acrylate moieties. DSC measurements showed that in the presence of polymers, cyt c is thermally unfolded in aqueous buffer at temperatures lowered by >20 °C as compared to thermal unfolding in the absence of polymers. Upon exposure to UV light, properties of the polymers chains were perturbed in situ, upon cis/trans isomerization of the azobenzene groups. In polymers displaying a photoresponsive polarity and hydrophobicity switch (conventional azobenzene), the stability of cyt c was not affected by the exposure to light. In contrast, when photoionization occurred (using an hydroxyl-azobenzene whose pKa can be photoshifted), unfolding was initiated upon exposure to light. Altogether, these results show that coulombic binding is a predominant driving force that facilitates unfolding in water/urea solutions. In regard to the design of light-responsive systems for protein handling and control of folding, we conclude that remote control of the coulombic interaction upon photoionization of chromophores can be more efficient than the more conventional photomodulation of polarity. © 2012 American Chemical Society. |
2011 |
Autocatalyses Article de journal R Plasson; A Brandenburg; L Jullien; H Bersini Journal of Physical Chemistry A, 115 (28), p. 8073–8085, 2011. @article{Plasson:2011a, title = {Autocatalyses}, author = {R Plasson and A Brandenburg and L Jullien and H Bersini}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960350219&doi=10.1021%2fjp110079p&partnerID=40&md5=5d640b81be3368a9b4b87f7a16fd5119}, doi = {10.1021/jp110079p}, year = {2011}, date = {2011-01-01}, journal = {Journal of Physical Chemistry A}, volume = {115}, number = {28}, pages = {8073--8085}, abstract = {Autocatalysis is a fundamental concept, used in a wide range of domains. From the most general definition of autocatalysis, that is, a process in which a chemical compound is able to catalyze its own formation, several different systems can be described. We detail the different categories of autocatalyses and compare them on the basis of their mechanistic, kinetic, and dynamic properties. It is shown how autocatalytic patterns can be generated by different systems of chemical reactions. With the notion of autocatalysis covering a large variety of mechanistic realizations with very similar behaviors, it is proposed that the key signature of autocatalysis is its kinetic pattern expressed in a mathematical form. © 2011 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Autocatalysis is a fundamental concept, used in a wide range of domains. From the most general definition of autocatalysis, that is, a process in which a chemical compound is able to catalyze its own formation, several different systems can be described. We detail the different categories of autocatalyses and compare them on the basis of their mechanistic, kinetic, and dynamic properties. It is shown how autocatalytic patterns can be generated by different systems of chemical reactions. With the notion of autocatalysis covering a large variety of mechanistic realizations with very similar behaviors, it is proposed that the key signature of autocatalysis is its kinetic pattern expressed in a mathematical form. © 2011 American Chemical Society. |
Autocatalysis: At the root of self-replication Article de journal R Plasson; A Brandenburg; L Jullien; H Bersini Artificial Life, 17 (3), p. 219–236, 2011. @article{Plasson:2011, title = {Autocatalysis: At the root of self-replication}, author = {R Plasson and A Brandenburg and L Jullien and H Bersini}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960494353&doi=10.1162%2fartl_a_00033&partnerID=40&md5=42a275d57ed71a4825c0fab5de24dd7a}, doi = {10.1162/artl_a_00033}, year = {2011}, date = {2011-01-01}, journal = {Artificial Life}, volume = {17}, number = {3}, pages = {219--236}, abstract = {Autocatalysis is a fundamental concept, used in a wide range of domains. From its most general definition, that is, a process in which a chemical compound is able to catalyze its own formation, several different systems can be described. We detail the different categories of autocatalyses, and compare them on the basis of their mechanistic, kinetic, and dynamic properties. It is shown how autocatalytic patterns can be generated by different systems of chemical reactions. The notion of autocatalysis covers a large variety of mechanistic realizations with very similar behaviors; it is proposed that its key signature is its kinetic pattern expressed in a mathematical form. This notion, while describing dynamic behaviors at the most fundamental level, is at the basis for developing higher-level concepts towards life: autocatalytic sets and autopoietic systems. © 2011 Massachusetts Institute of Technology.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Autocatalysis is a fundamental concept, used in a wide range of domains. From its most general definition, that is, a process in which a chemical compound is able to catalyze its own formation, several different systems can be described. We detail the different categories of autocatalyses, and compare them on the basis of their mechanistic, kinetic, and dynamic properties. It is shown how autocatalytic patterns can be generated by different systems of chemical reactions. The notion of autocatalysis covers a large variety of mechanistic realizations with very similar behaviors; it is proposed that its key signature is its kinetic pattern expressed in a mathematical form. This notion, while describing dynamic behaviors at the most fundamental level, is at the basis for developing higher-level concepts towards life: autocatalytic sets and autopoietic systems. © 2011 Massachusetts Institute of Technology. |
Kinetic and thermodynamic characterisation by heating in a microfluidic cell Article de journal K Zrelli; T Barilero; H Berthoumieux; T Le Saux; C Gosse; A Lemarchand; L Jullien Sensor Letters, 9 (6), p. 2332–2335, 2011. @article{Zrelli:2011, title = {Kinetic and thermodynamic characterisation by heating in a microfluidic cell}, author = {K Zrelli and T Barilero and H Berthoumieux and T Le Saux and C Gosse and A Lemarchand and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84862014294&doi=10.1166%2fsl.2011.1819&partnerID=40&md5=faecf5d436b7a9e626512b71f0f19249}, doi = {10.1166/sl.2011.1819}, year = {2011}, date = {2011-01-01}, journal = {Sensor Letters}, volume = {9}, number = {6}, pages = {2332--2335}, abstract = {We describe a technique that allows characterisation of both thermodynamic and kinetic parameters associated to DNA hybridization. This is achieved by means of a microdevice capable of modulating the interaction of the probe with the specific compound in the mixture. Copyright © 2011 American Scientific Publishers All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We describe a technique that allows characterisation of both thermodynamic and kinetic parameters associated to DNA hybridization. This is achieved by means of a microdevice capable of modulating the interaction of the probe with the specific compound in the mixture. Copyright © 2011 American Scientific Publishers All rights reserved. |
Photoinduced pH drops in water Article de journal M Emond; J Sun; J Grégoire; S Maurin; C Tribet; L Jullien Physical Chemistry Chemical Physics, 13 (14), p. 6493–6499, 2011. @article{Emond:2011, title = {Photoinduced pH drops in water}, author = {M Emond and J Sun and J Gr\'{e}goire and S Maurin and C Tribet and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952973660&doi=10.1039%2fc0cp02464c&partnerID=40&md5=34514ef4944c4bfa7ef5ebac9963af48}, doi = {10.1039/c0cp02464c}, year = {2011}, date = {2011-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {13}, number = {14}, pages = {6493--6499}, abstract = {A 2-hydroxyazobenzene platform has been evaluated to photorelease protons in aqueous solutions. Three different systems relying on molecular, supramolecular and polymeric strategies have been investigated in order to tune the water solubility and the thermodynamic and kinetic properties. This paper first reports on the syntheses and the physico chemical analyses for each system. Subsequently, we show that the three strategies are appropriate to reversibly photo-generate tunable pH drops in water up to one pH unit amplitude and at the 10-100 s timescale, upon transient illumination at 365 nm. © 2011 the Owner Societies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A 2-hydroxyazobenzene platform has been evaluated to photorelease protons in aqueous solutions. Three different systems relying on molecular, supramolecular and polymeric strategies have been investigated in order to tune the water solubility and the thermodynamic and kinetic properties. This paper first reports on the syntheses and the physico chemical analyses for each system. Subsequently, we show that the three strategies are appropriate to reversibly photo-generate tunable pH drops in water up to one pH unit amplitude and at the 10-100 s timescale, upon transient illumination at 365 nm. © 2011 the Owner Societies. |
Temperature modulated excitation and phase sensitive detection to selectively image DNA sequences Inproceedings K Zrelli; E Cavatore; T Barilero; H Berthoumieux; V Croquette; T Le Saux; L Jullien; A Lemarchand; C Gosse 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11, p. 2160–2163, 2011. @inproceedings{Zrelli:2011b, title = {Temperature modulated excitation and phase sensitive detection to selectively image DNA sequences}, author = {K Zrelli and E Cavatore and T Barilero and H Berthoumieux and V Croquette and T Le Saux and L Jullien and A Lemarchand and C Gosse}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052114195&doi=10.1109%2fTRANSDUCERS.2011.5969322&partnerID=40&md5=405f3c87fbb8e4447dc5eb485cc046e8}, doi = {10.1109/TRANSDUCERS.2011.5969322}, year = {2011}, date = {2011-01-01}, booktitle = {2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11}, pages = {2160--2163}, abstract = {Temperature oscillations allow one to modulate the concentration of reagents and products with given amplitude and phase shift, both parameters depending on the dynamics of the chemical system under study. We here rely on thermal excitation in a microdevice, associated with fluorescence video microscopy as well as image filtering protocols, to selectively enhance the signal issued from a labeled probe that hybridizes with a targeted oligonucleotide. Furthermore, by simply tuning the stimulation parameters, focus can be put either on the perfect match sequence or on some other one that bears a point mutation. © 2011 IEEE.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Temperature oscillations allow one to modulate the concentration of reagents and products with given amplitude and phase shift, both parameters depending on the dynamics of the chemical system under study. We here rely on thermal excitation in a microdevice, associated with fluorescence video microscopy as well as image filtering protocols, to selectively enhance the signal issued from a labeled probe that hybridizes with a targeted oligonucleotide. Furthermore, by simply tuning the stimulation parameters, focus can be put either on the perfect match sequence or on some other one that bears a point mutation. © 2011 IEEE. |
Temperature modulation and quadrature detection for selective titration of two-state exchanging reactants Article de journal K Zrelli; T Barilero; E Cavatore; H Berthoumieux; T Le Saux; V Croquette; A Lemarchand; C Gosse; L Jullien Analytical Chemistry, 83 (7), p. 2476–2484, 2011. @article{Zrelli:2011a, title = {Temperature modulation and quadrature detection for selective titration of two-state exchanging reactants}, author = {K Zrelli and T Barilero and E Cavatore and H Berthoumieux and T Le Saux and V Croquette and A Lemarchand and C Gosse and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953280715&doi=10.1021%2fac1026034&partnerID=40&md5=27af1d31b99d901d7b3b782f16a0329c}, doi = {10.1021/ac1026034}, year = {2011}, date = {2011-01-01}, journal = {Analytical Chemistry}, volume = {83}, number = {7}, pages = {2476--2484}, abstract = {Biological samples exhibit huge molecular diversity over large concentration ranges. Titrating a given compound in such mixtures is often difficult, and innovative strategies emphasizing selectivity are thus demanded. To overcome limitations inherent to thermodynamics, we here present a generic technique where discrimination relies on the dynamics of interaction between the target of interest and a probe introduced in excess. Considering an ensemble of two-state exchanging reactants submitted to temperature modulation, we first demonstrate that the amplitude of the out-of-phase concentration oscillations is maximum for every compound involved in a reaction whose equilibrium constant is equal to unity and whose relaxation time is equal to the inverse of the excitation angular frequency. Taking advantage of this feature, we next devise a highly specific detection protocol and validate it using a microfabricated resistive heater and an epifluorescence microscope, as well as labeled oligonucleotides to model species displaying various dynamic properties. As expected, quantification of a sought for strand is obtained even if interfering reagents are present in similar amounts. Moreover, our approach does not require any separation and is compatible with imaging. It could then benefit some of the numerous binding assays performed every day in life sciences. © 2011 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Biological samples exhibit huge molecular diversity over large concentration ranges. Titrating a given compound in such mixtures is often difficult, and innovative strategies emphasizing selectivity are thus demanded. To overcome limitations inherent to thermodynamics, we here present a generic technique where discrimination relies on the dynamics of interaction between the target of interest and a probe introduced in excess. Considering an ensemble of two-state exchanging reactants submitted to temperature modulation, we first demonstrate that the amplitude of the out-of-phase concentration oscillations is maximum for every compound involved in a reaction whose equilibrium constant is equal to unity and whose relaxation time is equal to the inverse of the excitation angular frequency. Taking advantage of this feature, we next devise a highly specific detection protocol and validate it using a microfabricated resistive heater and an epifluorescence microscope, as well as labeled oligonucleotides to model species displaying various dynamic properties. As expected, quantification of a sought for strand is obtained even if interfering reagents are present in similar amounts. Moreover, our approach does not require any separation and is compatible with imaging. It could then benefit some of the numerous binding assays performed every day in life sciences. © 2011 American Chemical Society. |
2010 |
2-Hydroxyazobenzenes to tailor pH Pulses and oscillations with light Article de journal M Emond; T L Saux; S Maurin; J -B Baudin; R Plasson; L Jullien Chemistry - A European Journal, 16 (29), p. 8822–8831, 2010. @article{Emond:2010, title = {2-Hydroxyazobenzenes to tailor pH Pulses and oscillations with light}, author = {M Emond and T L Saux and S Maurin and J -B Baudin and R Plasson and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955126007&doi=10.1002%2fchem.201000541&partnerID=40&md5=dcfd1d6c4e29b0265d1f1b84f612f306}, doi = {10.1002/chem.201000541}, year = {2010}, date = {2010-01-01}, journal = {Chemistry - A European Journal}, volume = {16}, number = {29}, pages = {8822--8831}, abstract = {This paper evaluates the 2hydroxyazobenzene platform for tailoring proton concentration pulses and oscillations with monochromatic light. The easily prepared 2-hydroxyazobenzenes exhibit large absorptions in the near-UV range. Photoisomerization was investigated by UV/Vis absorption, 1H NMR spectroscopy, and steady-state fluorescence emission. In the whole investigated series, the trans stereoisomer of the 2-hydroxyazobenzene motif provides the corresponding cis derivative with an action cross section in the 10 3M-1cm-1 range. At the same time, photoisomerization is accompanied by a significant pK drop of the phenol group. According to the phenyl-substituent pattern, cis-to-trans thermal back-isomerization can be tuned in the 10 ms-100 s range. Up to 2 units of reversible pH drops or pH oscillations on the 10 s timescale have been obtained by appropriately tailoring single-wavelength illumination of 2-hydroxyazobenzene solutions. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA. Weinheim.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper evaluates the 2hydroxyazobenzene platform for tailoring proton concentration pulses and oscillations with monochromatic light. The easily prepared 2-hydroxyazobenzenes exhibit large absorptions in the near-UV range. Photoisomerization was investigated by UV/Vis absorption, 1H NMR spectroscopy, and steady-state fluorescence emission. In the whole investigated series, the trans stereoisomer of the 2-hydroxyazobenzene motif provides the corresponding cis derivative with an action cross section in the 10 3M-1cm-1 range. At the same time, photoisomerization is accompanied by a significant pK drop of the phenol group. According to the phenyl-substituent pattern, cis-to-trans thermal back-isomerization can be tuned in the 10 ms-100 s range. Up to 2 units of reversible pH drops or pH oscillations on the 10 s timescale have been obtained by appropriately tailoring single-wavelength illumination of 2-hydroxyazobenzene solutions. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA. Weinheim. |
Photoactivation of the CreERT2 recombinase for conditional site-specific recombination with high spatiotemporal resolution Article de journal D K Sinha; P Neveu; N Gagey; I Aujard; T Le Saux; C Rampon; C Gauron; K Kawakami; C Leucht; L Bally-Cuif; M Volovitch; D Bensimon; L Jullien; S Vriz Zebrafish, 7 (2), p. 199–204, 2010. @article{Sinha:2010a, title = {Photoactivation of the CreERT2 recombinase for conditional site-specific recombination with high spatiotemporal resolution}, author = {D K Sinha and P Neveu and N Gagey and I Aujard and T Le Saux and C Rampon and C Gauron and K Kawakami and C Leucht and L Bally-Cuif and M Volovitch and D Bensimon and L Jullien and S Vriz}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953623529&doi=10.1089%2fzeb.2009.0632&partnerID=40&md5=e5fb039a397abb6510140bcd6b2b258b}, doi = {10.1089/zeb.2009.0632}, year = {2010}, date = {2010-01-01}, journal = {Zebrafish}, volume = {7}, number = {2}, pages = {199--204}, abstract = {We implemented a noninvasive optical method for the fast control of Cre recombinase in single cells of a live zebrafish embryo. Optical uncaging of the caged precursor of a nonendogeneous steroid by one- or two-photon illumination was used to restore Cre activity of the CreERT2 fusion protein in specific target cells. This method labels single cells irreversibly by inducing recombination in an appropriate reporter transgenic animal and thereby can achieve high spatiotemporal resolution in the control of gene expression. This technique could be used more generally to investigate important physiological processes (e.g., in embryogenesis, organ regeneration, or carcinogenesis) with high spatiotemporal resolution (single cell and 10-min scales). © Copyright 2010, Mary Ann Liebert, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We implemented a noninvasive optical method for the fast control of Cre recombinase in single cells of a live zebrafish embryo. Optical uncaging of the caged precursor of a nonendogeneous steroid by one- or two-photon illumination was used to restore Cre activity of the CreERT2 fusion protein in specific target cells. This method labels single cells irreversibly by inducing recombination in an appropriate reporter transgenic animal and thereby can achieve high spatiotemporal resolution in the control of gene expression. This technique could be used more generally to investigate important physiological processes (e.g., in embryogenesis, organ regeneration, or carcinogenesis) with high spatiotemporal resolution (single cell and 10-min scales). © Copyright 2010, Mary Ann Liebert, Inc. |
Photocontrol of protein activity in cultured cells and zebrafish with one- and two-photon illumination Article de journal D K Sinha; P Neveu; N Gagey; I Aujard; C Benbrahim-Bouzidi; T Le Saux; C Rampon; C Gauron; B Goetz; S Dubruille; M Baaden; M Volovitch; D Bensimon; S Vriz; L Jullien ChemBioChem, 11 (5), p. 653–663, 2010. @article{Sinha:2010, title = {Photocontrol of protein activity in cultured cells and zebrafish with one- and two-photon illumination}, author = {D K Sinha and P Neveu and N Gagey and I Aujard and C Benbrahim-Bouzidi and T Le Saux and C Rampon and C Gauron and B Goetz and S Dubruille and M Baaden and M Volovitch and D Bensimon and S Vriz and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949823382&doi=10.1002%2fcbic.201000008&partnerID=40&md5=4ac50ebf9ae4f10b80cc91f729b23969}, doi = {10.1002/cbic.201000008}, year = {2010}, date = {2010-01-01}, journal = {ChemBioChem}, volume = {11}, number = {5}, pages = {653--663}, abstract = {We have implemented a noninvasive optical method for the fast control of protein activity in a live zebrafish embryo. It relies on releasing a protein fused to a modified estrogen receptor ligand binding domain from its complex with cytoplasmic chaperones, upon the local photoactivation of a nonendogenous caged inducer. Molecular dynamics simulations were used to design cyclofen-OH, a photochemically stable inducer of the receptor specific for 4-hydroxy-tamoxifen (ERT2). Cyclofen-OH was easily synthesized in two steps with good yields. At submicromolar concentrations, it activates proteins fused to the ERT2 receptor. This was shown in cultured cells and in zebrafish embryos through emission properties and subcellular localization of properly engineered fluorescent proteins. Cyclofen-OH was successfully caged with various photolabile protecting groups. One particular caged compound was efficient in photoinducing the nuclear translocation of fluorescent proteins either globally (with 365 nm UV illumination) or locally (with a focused UV laser or with two-photon illumination at 750 nm). The present method for photocontrol of protein activity could be used more generally to investigate important physiological processes (e.g., in embryogenesis, organ regeneration and carcinogenesis) with high spatiotemporal resolution. © 2010 Wiley-VCH Verlag GmbH& Co. KGaA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We have implemented a noninvasive optical method for the fast control of protein activity in a live zebrafish embryo. It relies on releasing a protein fused to a modified estrogen receptor ligand binding domain from its complex with cytoplasmic chaperones, upon the local photoactivation of a nonendogenous caged inducer. Molecular dynamics simulations were used to design cyclofen-OH, a photochemically stable inducer of the receptor specific for 4-hydroxy-tamoxifen (ERT2). Cyclofen-OH was easily synthesized in two steps with good yields. At submicromolar concentrations, it activates proteins fused to the ERT2 receptor. This was shown in cultured cells and in zebrafish embryos through emission properties and subcellular localization of properly engineered fluorescent proteins. Cyclofen-OH was successfully caged with various photolabile protecting groups. One particular caged compound was efficient in photoinducing the nuclear translocation of fluorescent proteins either globally (with 365 nm UV illumination) or locally (with a focused UV laser or with two-photon illumination at 750 nm). The present method for photocontrol of protein activity could be used more generally to investigate important physiological processes (e.g., in embryogenesis, organ regeneration and carcinogenesis) with high spatiotemporal resolution. © 2010 Wiley-VCH Verlag GmbH& Co. KGaA. |
Temperature modulation and phase sensitive imaging to detect point mutations Inproceedings K Zrelli; T Barilero; E Cavatore; H Berthoumieux; V Croquette; A Lemarchand; L Jullien; T Le Saux; C Gosse 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010, p. 1271–1273, 2010. @inproceedings{Zrelli:2010, title = {Temperature modulation and phase sensitive imaging to detect point mutations}, author = {K Zrelli and T Barilero and E Cavatore and H Berthoumieux and V Croquette and A Lemarchand and L Jullien and T Le Saux and C Gosse}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884400328&partnerID=40&md5=25428d835811e78ea89388612cd16b98}, year = {2010}, date = {2010-01-01}, booktitle = {14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010}, volume = {2}, pages = {1271--1273}, abstract = {Temperature oscillations allow one to modulate the concentration of reagents and products with given amplitude and phase shift, both parameters depending on the dynamics of the chemical system under study. We here rely on thermal excitation in a microdevice, associated with fluorescence video microscopy as well as image filtering protocols, to selectively enhance the signal issued from a labeled probe that hybridizes with a targeted oligonucleotide. Furthermore, by simply tuning the stimulation parameters, focus can be put either on the perfect match sequence or on some other one that bears a point mutation.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Temperature oscillations allow one to modulate the concentration of reagents and products with given amplitude and phase shift, both parameters depending on the dynamics of the chemical system under study. We here rely on thermal excitation in a microdevice, associated with fluorescence video microscopy as well as image filtering protocols, to selectively enhance the signal issued from a labeled probe that hybridizes with a targeted oligonucleotide. Furthermore, by simply tuning the stimulation parameters, focus can be put either on the perfect match sequence or on some other one that bears a point mutation. |
2009 |
A two-color molecular beacon for microchip thermal mapping Inproceedings T Le Saux; T Barilero; O Jouannot; L Jullien; C Gosse Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, p. 2025–2027, 2009. @inproceedings{LeSaux:2009, title = {A two-color molecular beacon for microchip thermal mapping}, author = {T Le Saux and T Barilero and O Jouannot and L Jullien and C Gosse}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901775127&partnerID=40&md5=60be07b422860df20d0c23c9a147212d}, year = {2009}, date = {2009-01-01}, booktitle = {Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences}, pages = {2025--2027}, abstract = {We introduce a molecular thermometer for ratiometric dual-emission- wavelength measurements. Thermal mapping is performed by epifluorescence microscopy, the acquisition and data treatment procedures ensuring results that neither depend on the probe concentration or on the observation setup imperfections. As an application, we demonstrate Joule heating monitoring during electrokinetic injection. © 2009 CBMS.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } We introduce a molecular thermometer for ratiometric dual-emission- wavelength measurements. Thermal mapping is performed by epifluorescence microscopy, the acquisition and data treatment procedures ensuring results that neither depend on the probe concentration or on the observation setup imperfections. As an application, we demonstrate Joule heating monitoring during electrokinetic injection. © 2009 CBMS. |
Fluorescent thermometers for dual-emission-wavelength measurements: Molecular engineering and application to thermal imaging in a microsystem Article de journal T Barilero; T Le Saux; C Gosse; L Jullien Analytical Chemistry, 81 (19), p. 7988–8000, 2009. @article{Barilero:2009, title = {Fluorescent thermometers for dual-emission-wavelength measurements: Molecular engineering and application to thermal imaging in a microsystem}, author = {T Barilero and T Le Saux and C Gosse and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349624352&doi=10.1021%2fac901027f&partnerID=40&md5=79e5948e7f33f1573c5bd1570160215c}, doi = {10.1021/ac901027f}, year = {2009}, date = {2009-01-01}, journal = {Analytical Chemistry}, volume = {81}, number = {19}, pages = {7988--8000}, abstract = {To facilitate thermal imaging, particularly in microdevices, one has to favor molecular thermometers in which the response is independent of the probe concentration and of the observation setup imperfections. Hence, this paper introduces two temperature fluorescent probes for ratiometric dual-emission-wavelength measurements in aqueous solutions. They are based on a nonathermal chemical reaction, either a conformational transition or a protonation, that induces a modification of their emission spectra as the temperature changes. Relying on both a straightforward theoretical analysis and thorough photophysical, thermodynamic, and kinetic investigations, we demonstrate how the flexible design of these two thermometers can be optimized to face applications with various requirements in terms of operating temperature and wavelength ranges as well as temporal resolution. For instance, the present molecules, which can be used between 5 and 35°C, provide a relative sensitivity up to ∼ 9 × 10-2 K-1 and milli- to microsecond response times. Finally, we utilize a two-color molecular beacon, a probe belonging to the first series of thermometers, to image temperature profiles in a microfluidic cell heated by a resistive strip. The ratiometric analysis of the fluorescence emission at two different wavelengths is performed on a widely available dual-view microscope, illustrating both the simplicity and reliability of the thermal mapping protocol. © 2009 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } To facilitate thermal imaging, particularly in microdevices, one has to favor molecular thermometers in which the response is independent of the probe concentration and of the observation setup imperfections. Hence, this paper introduces two temperature fluorescent probes for ratiometric dual-emission-wavelength measurements in aqueous solutions. They are based on a nonathermal chemical reaction, either a conformational transition or a protonation, that induces a modification of their emission spectra as the temperature changes. Relying on both a straightforward theoretical analysis and thorough photophysical, thermodynamic, and kinetic investigations, we demonstrate how the flexible design of these two thermometers can be optimized to face applications with various requirements in terms of operating temperature and wavelength ranges as well as temporal resolution. For instance, the present molecules, which can be used between 5 and 35°C, provide a relative sensitivity up to ∼ 9 × 10-2 K-1 and milli- to microsecond response times. Finally, we utilize a two-color molecular beacon, a probe belonging to the first series of thermometers, to image temperature profiles in a microfluidic cell heated by a resistive strip. The ratiometric analysis of the fluorescence emission at two different wavelengths is performed on a widely available dual-view microscope, illustrating both the simplicity and reliability of the thermal mapping protocol. © 2009 American Chemical Society. |
Resonant response to temperature modulation for enzymatic dynamics characterization Article de journal H Berthoumieux; C Antoine; L Jullien; A Lemarchand Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 79 (2), 2009. @article{Berthoumieux:2009, title = {Resonant response to temperature modulation for enzymatic dynamics characterization}, author = {H Berthoumieux and C Antoine and L Jullien and A Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-61549099297&doi=10.1103%2fPhysRevE.79.021906&partnerID=40&md5=bde7b045fc3c9d9f1d85e3ffe3d07a17}, doi = {10.1103/PhysRevE.79.021906}, year = {2009}, date = {2009-01-01}, journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics}, volume = {79}, number = {2}, abstract = {We consider enzymes involved in a three-state Michaelis-Menten kinetics and submitted to well-chosen temperature modulations of small amplitude. From the first-order amplitudes of concentration oscillations, we design a response function that is maximum for targeted values of the chemical relaxation times. This resonant function can be used to screen a large set of enzymes and identify the one governed by the desired kinetics. The method gives access to all the dynamical parameters of the targeted enzyme without resorting to a fit. We show how to estimate the precision of this parameter determination and give some hints for experimental validation. © 2009 The American Physical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We consider enzymes involved in a three-state Michaelis-Menten kinetics and submitted to well-chosen temperature modulations of small amplitude. From the first-order amplitudes of concentration oscillations, we design a response function that is maximum for targeted values of the chemical relaxation times. This resonant function can be used to screen a large set of enzymes and identify the one governed by the desired kinetics. The method gives access to all the dynamical parameters of the targeted enzyme without resorting to a fit. We show how to estimate the precision of this parameter determination and give some hints for experimental validation. © 2009 The American Physical Society. |