AGROBACTERIUM TUMEFACIENS CONN II

Abstract

Two strains of A. tumefaciens Conn produced an agent which inhibited the growth of 12 other strains of A. tumefaciens, and of 1 strain each of A. radiobacter and Bacillus subtilis. Inhibition of bacterial growth could be reversed by adding 1 of a number of amino acids or peptides, notably alanylalanine. The antibiotic agent diffused rapidly through agar and dialyzing membranes. Trypsin, ribonuclease, or deoxyribonuclease did not destroy the activity of the antibiotic agent in agar. Water extracts of the agar could be concentrated; the activity of such crude concentrates was not appreciably affected by a few minutes of boiling, by freezing, or by bubbling air through the concentrated extract. The crude concentrates also contained a substance which stimulated the growth of a number of bacteria including A. tumefaciens and B. megaterium. Attempts to correlate the tumor-inducing activity of the bacteria with the above agent, failed.