[Nucleotide composition and homology of the DNA of parasitic Leptospira].

The study of DNA in parasitic leptospirae of different serovariants by the method of molecular hybridization has revealed two groups differing in their homology level. The homology of nucleic acids has been found to correlate with serological properties. The serovariants ensuring cross immunity are characterized by the high level of homology of their DNA.

[Significance of an increase in the titer of agglutinins in the microagglutination test in leptospirosis].

The authors considered different views of investigators on the diagnostic antibody titre level in the microagglutination test (MAT) in leptospirosis of man and animals. Some of them took into consideration MAT in low titres (1:10-1:20), and others - in high only (1:400, 1:1000), which gave no possibility to assess the state of leptospirosis morbidity. The authors suggest that the assessment of the level of the titres in single and repeated studies should be approached differentially.

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.