The Isolation and Composition of the Nucleic Acids of Aerobacter aerogenes

Abstract

SUMMARY: The nucleic acids were isolated from Aerobacter aerogenes by extraction of mechanically disintegrated organisms with 0.14M-sodium chloride at pH 7.5. Upon subsequent isolation, about 80% of the deoxyribonucleic acid (DNA) originally contained in the organisms was obtained, but only about 50% of the ribonucleic acid (RNA). The loss of RNA was mainly due to enzymic degradation. By extraction of A. aerogenes with 1% sodium cholate at 60., enzymic degradation was virtually eliminated and a good yield of both DNA and RNA obtained. They were relatively undegraded and both showed evidence of the presence of hydrogen bonds. The amounts of the purine and pyrimidine bases in both types of nucleic acid were determined. The DNA and RNA from the normal streptomycin-sensitive strain of A. aerogenes differed significantly in base composition from the corresponding nucleic acids from a strain which had been trained to grow in 5% (w/v) streptomycin.