Poly(adenosine diphosphate ribose) polymerase purification in an aqueous/organic-solvent system [proceedings].

plasmid DNA. Those fragments represent the homologous Ti-plasmid DNA segment 8,um long (1 5 % of the Ti-plasmid). An argument that this region of the plasmid contains genes essential for the expression of oncogenicity came from the analysis of a deletion mutant in the Ti-plasmid (Hernalsteens et al., 1975). Since this deletion mutant is unable to confer oncogenicity and has lost exactly those two fragments of Ti-plasmid produced by digestion with enzyme EcoRI that are present in all Agrobacterium tumefaciens strains, we have good indications for the correlation between this general Ti-plasmid DNA segment and the ability for tumour induction.