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Liquid crystal phases of DNA: Evaluation of DNA organization by two‐photon fluorescence microscopy and polarization analysis
Author(s) -
OlesiakBanska Joanna,
Mojzisova Halina,
Chauvat Dominique,
Zielinski Marcin,
Matczyszyn Katarzyna,
Tauc Patrick,
Zyss Joseph
Publication year - 2011
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.21583
Subject(s) - chemistry , fluorescence , liquid crystal , dna , propidium iodide , fluorescence microscope , microscopy , fluorescence anisotropy , polarized light microscopy , polarization (electrochemistry) , intercalation (chemistry) , polarization microscopy , crystallography , photochemistry , optics , physics , organic chemistry , apoptosis , biochemistry , programmed cell death
We report on the investigation of the structure of DNA liquid crystal (LC) phases by means of polarization sensitive two‐photon microscopy (PSTPM). DNA was stained with fluorescent dyes, an intercalator propidium iodide, or a groove binder Hoechst 3342, and the angular dependence of the intensity of two‐photon excited fluorescence emitted by the dye was collected. The local orientation of DNA molecules in cholesteric and columnar LC phases was established on the basis of the relative angle between the transition dipole of the dye and the long axis of DNA helix. Three‐dimensional images of the cholesteric phase were obtained making use of the intrinsic 3D resolving ability of two‐photon microscopy. We also discuss the influence of dyes on the parameters of DNA LC phases and comment on advantages and limitations of the PSTPM technique in comparison with other LC characterization techniques. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 365–375, 2011