title: Isolation of Dane particles containing a DNA strand by metrizamide density gradient.
abstract: Dane-particle cores labelled with [3H]TTP were subjected to ultracentrifugation in a metrizamide density gradient. Two populations of core particles with different densities were obtained, and radioactivity was found only in the cores that sedimented at the lower density (1.19-1.23 g/cm3). All the cores in this group, when spread in a monolayer, were found to expel a closed circular double-stranded DNA molecule. In contrast, the core particles that sedimented at the higher density (1.23-1.27 g/cm3) were not associated with radioactivity, nor was any DNA strand extruded from them. These results show that metrizamide density gradients allow the separation of complete hepatitis B virions for the study of viral DNA.
mesh_terms: D002499:Centrifugation, Density Gradient; D004270:DNA, Circular / Q000032:analysis*; D004279:DNA, Viral / Q000032:analysis*; D006511:Hepatitis B Antigens / Q000032:analysis / Q000302:isolation & purification*; D008793:Metrizamide
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral; D006511:Hepatitis B Antigens; D008793:Metrizamide