Electric dichroism

Antosiewicz, J., Porschke, D. Electrostatics of hemoglobins from measurements of the electric dichroism and computer simulations. Biophys. J. 68 (1995) 655-664. 

Figure 4.1. Time scales for rotational motions of long DNAs that contribute to the relaxation of the optical anisotropy r(t). Experimental methods used to study these motions in different time ranges are also indicated along with the authors and dates of some early work in each case. FPA, Fluorescence polarization anisotropy (Refs. 15, 18-20, and 87) TPD, transient photodichroism (Refs. 28 and 62) TEB, transient electric birefringence (Refs. 26 and 27) DDLS, depolarized dynamic light scattering (Ref. 116) TED, transient electric dichroism (Refs. 25, 115, and 130) Microscopy, time-resolved fluorescent microscopy (Ref. 176).

Figure 4.11. Longest bending relax- 200 ation time t, as a function of (W-f-1 )A The symbols are the fast 8Q0 components detected in the off-field transient electric dichroism data of...

Electric dichroism data indicate that, when the Z-form is induced by [Co(NH3)6]3 +, the B-Z junctions are not highly flexible.1 130-1 Static light... 

The ability of DNA-binding drugs to induce chromatin condensation calls for in-depth studies, because the biological consequence of chromatin condensation is its loss of transcriptional ability. Therefore it might be a mechanism of transcription inhibition by the reversible DNA binders. The first report in this line (Sen and Crothers, 1986) employed transient electric dichroism to study the ability of the drugs to induce folding of chromatin from the 10- to 30-nm fiber either by... 

Electric dichroism spectroscopy in the vacuum ultraviolet. Thietane, tetrahydrothiophene, and tetrahydrothiopyran. ... 

Fredericq E, Houssier C (1973) Electric Dichroism and Electric Birefringence. Clarendon Press, Oxford... 

Fredericq, E. Houssier, C. "Electric Dichroism and Electric Birefringence" Clarendon Preas Oxford, 1973 P-92. 

Another original approach to the application of electric dichroism for the characterization of colloidal particles is due to Tolstoi et al. ° and, with regard to macromolecular solutions, to Dvorkin et al. ° and later authors. ... 

Hogan M, Dattagupta N, Crothers DM. Transient electric dichroism of rodlike DNA molecules. Proc Natl Acad Sci USA 1978 75 195-199. 

Yamaoka K, Fukudome K, Matsuda K. Electric field orientation of nucleic acids in aqueous solutions. 3. Non-Kerr-law behavior of high molecular weight DNA at weak fields as revealed by electric birefringence and electric dichroism. J Phys Chem 1992 96 7131-7136. 

Matsuda K, Yamaoka K. Electric birefringence and electric dichroism of son-... 

Rau DC, Charney E. Electric dichroism of DNA. Influence of ionic environment on the electric polarizability. Biophys Chem 1983 17 35-50. 

Electric dichroism and bire/ringencelphoto electric dichroismicircular dichroism... 

Electrooptical methods (electrochromism) which are more accurate but which are experimentally more difficult include electric polarization of fluorescence or phosphorescence, electric dichroism, and absorption spectra in the vapor phase in an electric field (Stark effect). 

A. R. Blythe, Electrical Properties of Polymers, Cambridge University Press, Cambridge, 1979. E. Fredericq and C.Houssier, Electric Dichroism and Electric Birefringence, Clarendon Press, Oxford, 1973. 

E. Fredericq and C. Houssier, Electric Dichroism and Electric Birefringence Clarendon, Oxford (1973). 

In solutions and suspensions of anisotropic molecules directing external forces such as a hydrodynamic flow or electric field forces may cause signal changes 55 originating from molecule rotations. In particular optically and electrically anisotropic (dipolar or polarizable) macromolecules exhibit major electric dichroism and electric birefringence. 

The time course of orientational changes induced by electric fields contains information on the orientation mechanism, and on the electrical and geometrical properties (main dipole axis, length) of the aligning and deorienting molecules. For instance, permanent dipole orientation of a given particle type in the presence of a constant electric field builds up with zero slope and has two modes, whereas the build-up of induced dipole orientation starts with maximum slope and is characterized by only one time constant. The deorientation relaxation of a system of identical particles, after termination of the step pulse, is monophasic, independently of the presence of permanent or induced dipoles. Table 3 summarizes the characteristic features of the rotational kinetics indicated by electric dichroism and birefringence for small perturbations. We see that there are a number of specific relationships to differentiate between permanent and induced dipole mechanism. In particular, the technique of field-reversal is a sensitive indicator for the relative contributions of permanent or induced dipoles. 

Sauer and Calvin (1962) demonstrated the orientation of some pigment molecules in spinach quantasomes. These particles exhibit electric birefringence and electric dichroism. Thus the orientation of pigment molecules is not solely related to the whole lamellar system, but is a property of the basic macromolecular particle involved in quantum conversion. 

HYDROPHOBIC REGION OF POLY(STYRENESULFONIC ACID) AS STUDIED BY ELECTRIC DICHROISM MEASUREMENTS... 

The nature of the hydrophobic region in poIy(styrenesuIfonic acid) was studied by the electric dichroism measurements when the polymer intereacted with a metal chelate cation. The chelates used were bis(2-(2-pyridylazo)-I-naphthoI)cobaIt(III), bis(l-(2-pyridylazo)-2-naphthol)cobaIt (III) and bis(10-(2-pyridyIazo)-9-phenanthroI)cobaIt(ni). Far all the systems investigated, the bound chelates were concluded to have their aromatic ligands nicely faced with the phenyl rings of the polyelectrolyte residues. The results are considered to present the molecular basis for the hydrophobicity of the concerned polymer. 

This communication reports that the electric dichroism measurements give an important clue to understanding the hydrophobic interaction of a polymer with a small molecule. Electric dichroism of a polymer solution is caused by the orientation of a polymer chain in the direction of an intense electric field. If a polymer binds a small... 

Electric dichroism was measured for a solution of PSS and the metal chelates at the various P/M ratios. When the square electric field pulse (1 ms, 4 kvolt) was imposed on the solution, the transient change of transmittance was observed as shown in Fig. 5. The amplitude of the signal depended on the ai le (0) between the polarization of a monitoring light and the electric field,5... 

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