We are delighted to announce Professor Damien Baigl (ENS/UPMC/CNRS) as the 2016 Soft Matter Lectureship winner.
The Soft Matter Lectureship, now in its seventh year, is an annual award that honours an early-stage career researcher for their significant contribution to the soft matter field. The recipient is selected by the Soft Matter Editorial Board from a list of candidates nominated by the community.
Read on to find out more about …
The reactivity, speciation and solvation structure of CO2 in carbonate melts are relevant both for the fate of carbon in deep geological formations and for its electroreduction to CO, to be used as fuel, by means of solvation in a molten carbonate electrolyte. In particular, the high solubility of CO2 in carbonate melts has been tentatively attributed to the formation of a new carbon species, the pyrocarbonate anion, C2O52-. In this work we study, by _rst principles molecular dynamics simulations, the behaviour of CO2 in molten calcium carbonate. We _nd that pyrocarbonate forms spontaneously and the identity of the CO2 molecule is quickly lost through O2- exchange. The transport of CO2 in this molten carbonate thus occurs in a fashion similar to the Grotthuss mechanism in water, and is three times faster than molecular diffusion. This shows that Grotthuss- like transport is more general than thought so far.
N’hésitez pas à consulter le communiqué de presse associé à cet article : Un étonnant mécanisme de diffusion de CO2 dans les carbonates fondus
References:
Carbon dioxide transport in molten calcium carbonate occurs through an oxo-Grotthuss mechanism via a pyrocarbonate anion
Dario Corradini, François-Xavier Coudert, and Rodolphe Vuilleumier
Nature Chemistry, 2016, Feb.
doi:10.1038/nchem.2450
This paper presents Yellow Fluorescence-Activating and absorption-Shifting Tag (Y-FAST), a small monomeric protein tag, half as large as the green fluorescent protein, enabling fluorescent labeling of proteins in a reversible and specific manner through the reversible binding and activation of a cell-permeant and nontoxic fluorogenic ligand (a socalled fluorogen). A unique fluorogen activation mechanism based on two spectroscopic changes, increase of fluorescence quantum yield and absorption red shift, provides high labeling selectivity. Y-FAST was engineered from the 14-kDa photoactive yellow protein by directed evolution using yeast display and fluorescence-activated cell sorting. Y-FAST is as bright as common fluorescent proteins, exhibits good photostability, and allows the efficient labeling of proteins in various organelles and hosts. Upon fluorogen binding, fluorescence appears instantaneously, allowing monitoring of rapid processes in near real time. Y-FAST distinguishes itself from other tagging systems because the fluorogen binding is highly dynamic and fully reversible, which enables rapid labeling and unlabeling of proteins by addition and withdrawal of the fluorogen, opening new exciting prospects for the development of multiplexing imaging protocols based on sequential labeling.
Consultez le communiqué de presse relatif à cet article : Un interrupteur fluorescent pour le marquage des protéines.
References:
Small fluorescence-activating and absorption-shifting tag for tunable protein imaging in vivo
Marie-Aude Plamont, Emmanuelle Billon-Denis, Sylvie Maurin, Carole Gauron, Frederico M. Pimenta, Christian G. Specht, Jian Shi, Jérôme Quérard, Buyan Pan, Julien Rossignol, Karine Moncoq, Nelly Morellet, Michel Volovitch, Ewen Lescop, Yong Chen, Antoine Triller, Sophie Vriz, Thomas Le Saux, Ludovic Jullien, and Arnaud Gautier
Proceedings of the National Academy of Sciences, Volume 113 n°.3, January 2016, Pages 497-502
Manon Guille-Collignon, Maître de Conférence au Pôle Électrochimie du Département de Chimie de l’ENS, a été nominée « membre junior » à l’Institut Universitaire de France (IUF).
L’IUF a pour mission de favoriser le développement de la recherche de haut niveau dans les universités et de renforcer l’interdisciplinarité. Créé par le décret du 26 août 1991, sous la forme d’un service du ministère de l’Enseignement supérieur et de la Recherche, il vient de fêter ses 20 ans.
Les enseignants-chercheurs qui y sont nommés sont distingués pour l’excellence de leur activité scientifique, attestée par leur rayonnement international.
External control of DNA melting and hybridization, a key step in bio- and DNA nanotechnology, is commonly achieved with temperature. The use of light to direct this process is a challenging alternative, which has been only possible with a DNA modification, such as covalent grafting or mismatch introduction, so far. Here we describe the first photocontrol of DNA melting that relies on the addition of a molecule that noncovalently interacts with unmodified DNA and affects its melting properties in a photoreversible and highly robust manner, without any prerequisite in the length or sequence of the target DNA molecule. We synthesize azobenzene-containing guanidinium derivatives and show that a bivalent molecule with a conformation-dependent binding mode, AzoDiGua, strongly increases the melting temperature (Tm) of DNA under dark conditions because its trans isomer intercalates in the DNA double helix. Upon UV irradiation at 365 nm, the trans–cis isomerization induced the ejection of AzoDiGua from the intercalation binding sites, resulting in a decrease in Tm up to 18 °C. This illumination-dependent Tm shift is observed on many types of DNA, from self-complementary single-stranded or double-stranded oligonucleotides to long genomic duplex DNA molecules. Finally, we show that simply adding AzoDiGua allows us to photoreversibly control the assembly/disassembly of a DNA nanostructure at constant temperature, as demonstrated here with a self-hybridized DNA hairpin. We anticipate that this strategy will be the key ingredient in a new and generic way of placing DNA-based bio- and nanotechnologies under dynamic control by light.
Consultez le communiqué de presse relatif à cet article : ADN (dé)zippé par la lumière !
References:
Photodependent Melting of Unmodified DNA Using a Photosensitive Intercalator: A New and Generic Tool for Photoreversible Assembly of DNA Nanostructures at Constant Temperature
Anna Bergen, Sergii Rudiuk, Mathieu Morel, Thomas Le Saux, Heiko Ihmels, and Damien Baigl
Nano Letters, 2016, 16 (1), pp 773–780
doi : 10.1021/acs.nanolett.5b04762
