Physical characteristics of DNA from bacteriophages of Agrobacterium tumefaciens.

DNA was extracted from isolates of bacteriophages grown on virulent and avirulent strains of Agrobacterium tumefaciens. Molecular weights of DNA from phages isolated from the virulent A. tumefaciens (IIBV7) were about 41.5 X 10(6) daltons, while those from the avirulent A. tumefaciens (IIBNV6) were about 32.5 X 10(6) daltons. The buoyant densities of the four DNA's ranged from 1.7086 to 1.7089 g/cm3, values that were not significantly different. DNA-DNA hybridization studies also indicated that the four phages were closely related. Attempts to induce tumors with phage DNA were unsuccessful.