Variation in the intensity of scattered light by solutions of DNA subjected to an electric field

✍ Scribed by A. Scheludko; S. Stoylov

• Publisher: Wiley (John Wiley & Sons)
• Year: 1967
• Tongue: English
• Weight: 210 KB
• Volume: 5
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1967.360050806

✦ Synopsis

Preliminary experiments have been carried out which measure the variation in t.he intensity of the light scattered by DNA solutions under the iduence of an electric field.

Data have been collected on the length of DNA molecules, their electric polarizability, and their dispersion behavior.

Recently, several papers have appeared which discuss electro-optical effects of nucleic These papers are concerned with variations in the dichroism2s6 and double birefringen~e~-~p~,~ of DNA solutions subjected to an electric field. It is interesting to note that the results reported in these papers agree only qualitatively. This arises chiefly from differences in the methods of preparation of the samples as well as from differences in experimental conditions, such as concentration and ionic strength. For example, in addition to an error of Dworkin12 which has since been c ~r r e c t e d , ~ there exists lack of agreement in values obtained for the saturation electric field strength. (This is the value of the electric field strength beyond which the optical effect no longer increases.) It appears that the strong dependence of the electric polarizability on the salt content established for rigid particles798 is not always taken into account.

Variation in the intensity of the scattered light has been observed for colloid solutions, such as those of bentonite, polygorskite, and tobacco mosaic virus, in the presence of an electric field.Qp10 This effect can be mathematically expressed as : ff = (I, -Io)/Io