[Dynamic and static chromatin].

It was found that the dependence of the viscosity of calf thymus chromatin dispersions and human leukocytes on ethidium bromide concentration had two peaks indicative of domains with circular supercoiled DNA and varying resistance to ultrasound in the cells and isolated chromatin. The hypothesis of V. D. Paponov and P. S. Gromov (Bull. Exp. Biol. Med., N5, 590, 1985) on the transformation of static relations of nucleosome DNA-containing nuclei into dynamic, after chromatin exposure to ultrasound due to DNA linearization in chromatin domains possessing circular supercoiled DNA, has been confirmed.