title: Early and late helix-coil transitions in closed circular DNA. The number of superhelical turns in polyoma DNA.
mesh_terms: D002499:Centrifugation, Density Gradient; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004269:DNA, Bacterial; D004279:DNA, Viral / Q000032:analysis; D003720:Densitometry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008433:Mathematics; D009691:Nucleic Acid Denaturation; D011120:Polyomavirus
chemical_list: D004269:DNA, Bacterial; D004279:DNA, Viral