[The study on homology of leptospires with molecular hybridization]

Homology of leptospires from different genus, different serogroups were studied with molecular hybridization. Leptospiral DNAs were extracted and purified with phenolchloroform-isoamylalcohol method. Alpha 32P-dCTP was used to label DNA from L. interrogans serogroup icterohaemorrhagiae serovar lai strain 017 as a DNA probe, and hybridized with DNAs of 2 genus, 5 serogroups of leptospires represented by 6 strains on NC filter. Four serogroups of pathogenic leptospires which caused endemic disease in Sichuan Province were also detected by the probe. The results showed that L. interrogans serogroup icterohaemorrhagiae, serogroup autumnalis and serogroup hebdomadis had a high degree of homology while there was a low degree of homology between L. interrogans and L. biflexa and Leptonema illini. Four major serogroups of pathogenic leptospires in Sichuan Province, with their high degree of homology, could be detected by a radiolabelled probe from serogroup icterohaemorrhagiae. Hybridization may be used as a tool for diagnosis of leptospirosis in human beings and animals.