[Structural differences of the supramolecular DNA complex from tumor strain cells].

Elastoviscosimetric examination was carried out to study the structure of supramolecular DNA complexes obtained from transplantable tumor strain cells and those of the same strains showing pronounced growth in synthetic culture media. The supramolecular DNA complex was isolated as a nucleoid and examined by ethidium bromide elastoviscosimetric titration method. Levels of supercoiled DNA were found to be significantly lower in the chromatin of cells of in vitro growing strains, as compared to parental strain cells where the said type of DNA predominated. Two patterns of DNA compact packing--supercoiled-domain and one characterized by a faster bond between DNA and non-histone proteins, and single-stranded DNA areas preexisting in domains--were suggested.