DNA, SuperhelicalDNADNA DamageDNA ReplicationNucleic Acid ConformationDNA, CircularDNA-Binding ProteinsCells, CulturedDNA Topoisomerases, Type IEthidiumOsmium TetroxidePlasmidsDNA, ViralSimian virus 40Electrophoresis, Agar GelEndonucleasesDeoxyribonucleasesColiphagesEscherichia coliSingle-Strand Specific DNA and RNA EndonucleasesNucleic Acid DenaturationCarbodiimidesDeoxyribonucleoproteinsPolydeoxyribonucleotidesBromosuccinimideHistonesOsmolar ConcentrationDNA, Single-StrandedBase SequenceNucleosomesDNA, BacterialTyrothricinCentrifugation, Density GradientNovobiocinNucleoproteinsKinetics