DNA, SuperhelicalNucleic Acid ConformationDNA, CircularDNA Topoisomerases, Type IEthidiumOsmium TetroxidePlasmidsDNA, ViralSimian virus 40Electrophoresis, Agar GelEndonucleasesDeoxyribonucleasesColiphagesEscherichia coliSingle-Strand Specific DNA and RNA EndonucleasesDNANucleic Acid DenaturationCarbodiimidesDeoxyribonucleoproteinsPolydeoxyribonucleotidesBromosuccinimideHistonesOsmolar ConcentrationDNA, Single-StrandedBase SequenceNucleosomesDNA, BacterialTyrothricinCentrifugation, Density GradientNovobiocinNucleoproteinsKinetics