title: Circular deoxyribonucleic acid from Shigella dysenteriae Y6R.
abstract: Circular deoxyribonucleic acid was isolated from Shigella dysenteriae Y6R and was found to consist of six species having molecular weights of 10(6), 1.3 x 10(6), 2.6 x 10(6), 3.8 x 10(6), 20 x 10(6), and 24 x 10(6) daltons. These size classes were partially resolved by sucrose density gradient centrifugation. The minicircles (10(6) and 1.3 x 10(6)) were found to have a buoyant density in CsCl of 1.710 g/ml. The 3.8 x 10(6) dalton class had a density of 1.707 g/ml. The two largest species had a density of 1.702 g/ml. Two other strains, S. sonnei II and S. dysenteriae 60, also contained circular deoxyribonucleic acid.
mesh_terms: D002499:Centrifugation, Density Gradient; D004269:DNA, Bacterial / Q000032:analysis* / Q000302:isolation & purification; D008854:Microscopy, Electron; D008970:Molecular Weight; D010759:Phosphorus Isotopes; D012762:Shigella dysenteriae / Q000032:analysis*; D012764:Shigella sonnei / Q000032:analysis; D014461:Ultracentrifugation
chemical_list: D004269:DNA, Bacterial; D010759:Phosphorus Isotopes