Attempts to induce tumours with nucleic acid preparations from Agrobacterium tumefaciens

Nucleic acid preparations from Agrobacterium tumefaciens (Smith & Townsend) Conn. have been tested for tumorigenic activity on a number of bioassay systems including carrot root explants, sunflower and tobacco stem segments, callus cultures of sunflower, tobacco and carrot, and sunflower stems. The methods used to isolate and test the DNA included those which have been reported to be successful for the induction of tumours. Strict precautions were taken to ensure that the DNA samples used in the tests were free of viable bacterial cells. In the large number of tests carried out under various experimental conditions there was no evidence for the induction of tumours with bacterial DNA.