Nucleic acid content and nucleotide composition of DNA in leptospirae

The contents of DNA and RNA were studied in 9 strains of leptospirae and the composition of nitrogen bases of DNA in 20 strains of pathogenic and saprophytic leptospirae. It has been found that leptospirae contain a high per cent ration of nucleic acids. According to the nucleotide composition, the family of Leptospira as a whole belongs to the AT-type. According to overall guanine and cytosine contents, the investigated strains of pathogenic leptospirae fall into 3 groups and differ from the seprophytic strains. With respect to the limited number of the investigated strains, the DNA nucleotide composition of leptospirae can be used as a supplementary biochemical criterion in the classification of leptospirae.