Biopolymers and cell. 1988. Volume 4. № 4. 203 - 211

D. Yu. Blokhin, V. A. Struchkov

CAPILLARY VISCOELASTOMETRY OF EUKARYOTIC NUCLEOIDS

Summary

    The method of capillary viscoelastometry was used to study structural peculiarities of supramolecular complexes (SC DNA) at different levels of their organization (nucleoids and alkaline lysates) in eukaryotic cells mud loach sperm, P388, L1210, S37. The de¬pendence of SC DNA viscoelasticity on time of lysic and ionic strength was studied. Velocity constants of nucleoid relaxation of various eukaryotic cells are shown to be significantly different. The curves of viscoelastometric titration of nucleoid of this eukaryotic cells with the ethidium bromide has a biphasic shape typical of supercoiled DNA, obtained by sedimentation. It is detected that the change in viscoelasticitic cha¬racteristics of L1210 nucleoids is not due to the action of endogenic proteases, since the electrophoretic composition of nucleoid proteins remained constant. Under these expe¬rimental conditions the nucleases were not active too. The method of capillary visco¬elastometry appears to be enough informative and sensitive in studies of SC DNA properties.