Laboratoire P.A.S.T.E.U.R

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Photochemical properties of Spinach and its use in selective imaging

We propose a dynamic model that accounts for the photochemical behavior of the Spinach system, a recently described fluorescent probe for RNA imaging. We exploit the dynamic fluorogen exchange and the unprecedented photoconversion properties in a non-covalent fluorescence turn-on system to significantly improve signal-to-background ratio during long-term microscopy imaging.

Spatiotemporal control of microtubule nucleation and assembly using magnetic nanoparticles

Cell fate decisions and cellular functions are dictated by the spatiotemporal dynamics of molecular signaling networks. However, the techniques available to examine the spatiotemporal properties of these intracellular processes remain limited. Here we report a method to artificially control in space and time such signaling pathways using magnetic nanoparticles conjugated to key regulatory proteins.

Energy propagation throughout a protometabolism leading to the local emergence of singular stationary concentration profiles.

Living systems rely on chains of energy transfer to maintain their metabolism from an energy source. This task requires functionally-identified components and organizations. However propagation of a sustained energy flux throughout a cascade of reaction cycles has never been reproduced at steady-state in a simple chemical system.

Extension of Marcus Picture for Electron Transfer Reactions with Large Solvation Changes

We showed, using first-principle molecular dynamics simulations, that the standard Marcus theory of charge transfer reaction in solution, relying on a linear solvent response approximation, and involving two parameters, the reorganization energy and the reaction free-energy parameter, may fail when the solvation has a different character in the reactant and product state. Such situation arise for even simple half oxydo- reduction reactions involving the Cu+/Cu2+ or Ag/Ag+ couples in water. We proposed theoretical extensions that exhibit the correct non-linear response behavior and reproduce the simulation results quantitatively, whereas Marcus theory breaks down.

Nanoelectrodes for Determination of Reactive Oxygen and Nitrogen Species inside Murine Macrophages

Reactive oxygen and nitrogen species (ROS and RNS) produced by macrophages are essential for protecting a human body against bacteria and viruses through digestion of ingested bodies in specific vacuoles. However, the issue concerning the potential leakage of ROS/RNS from vacuoles has been raised as a tentative explanation to some illness (e.g., gout). The purpose of this work was to investigate quantitatively and kinetically this issue.