title: Catenated circular DNA molecules in HeLa cell mitochondria.
mesh_terms: D002499:Centrifugation, Density Gradient; D055598:Chemical Phenomena; D002621:Chemistry; D003582:Cytogenetics; D004273:DNA, Neoplasm / Q000032:analysis*; D005260:Female; D006367:HeLa Cells; D006801:Humans; D008854:Microscopy, Electron; D008928:Mitochondria / Q000032:analysis*; D008956:Models, Chemical
chemical_list: D004273:DNA, Neoplasm