title: Anisotropic Brownian motion in ordered phases of DNA fragments.
abstract: Using Fluorescence Recovery After Photobleaching, we investigate the Brownian motion of DNA rod-like fragments in two distinct anisotropic phases with a local nematic symmetry. The height of the measurement volume ensures the averaging of the anisotropy of the in-plane diffusive motion parallel or perpendicular to the local nematic director in aligned domains. Still, as shown in using a model specifically designed to handle such a situation and predicting a non-Gaussian shape for the bleached spot as fluorescence recovery proceeds, the two distinct diffusion coefficients of the DNA particles can be retrieved from data analysis. In the first system investigated (a ternary DNA-lipid lamellar complex), the magnitude and anisotropy of the diffusion coefficient of the DNA fragments confined by the lipid bilayers are obtained for the first time. In the second, binary DNA-solvent system, the magnitude of the diffusion coefficient is found to decrease markedly as DNA concentration is increased from isotropic to cholesteric phase. In addition, the diffusion coefficient anisotropy measured within cholesteric domains in the phase coexistence region increases with concentration, and eventually reaches a high value in the cholesteric phase.
authors.affiliation: Université de Bordeaux, Centre de recherche Paul-Pascal - CNRS, 115 avenue du Docteur-Schweitzer, F-33600, Pessac, France.
authors.forename: J
authors.initials: J
authors.lastname: Dobrindt
authors.forename: E
authors.initials: E
authors.lastname: Rodrigo Teixeira da Silva
authors.forename: C
authors.initials: C
authors.lastname: Alves
authors.forename: C L P
authors.initials: CL
authors.lastname: Oliveira
authors.forename: F
authors.initials: F
authors.lastname: Nallet
authors.forename: E
authors.initials: E
authors.lastname: Andreoli de Oliveira
authors.forename: L
authors.initials: L
authors.lastname: Navailles
mesh_terms: D016880:Anisotropy; D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D053938:DNA Fragmentation; D004058:Diffusion; D005453:Fluorescence; D008051:Lipid Bilayers / Q000737:chemistry; D008956:Models, Chemical; D009038:Motion; D038761:Photobleaching
chemical_list: D008051:Lipid Bilayers; D004247:DNA