Characterization and grouping of Trypanosoma cruzi stocks by DNA base-specific fluorochromes and discriminant analysis.

Fluorochromes with G-C and A-T specificity were used for a single-cell DNA analysis of the blood-stream forms of 14 Trypanosoma cruzi stocks in a cytofluorometric assay. The kinetoplast contained 22.3%-37.9% of the total DNA G-C base content and 42.7%-63.5% of the total DNA A-T base content. In spite of these differences, the mean base A-T/G-C ratio of the total DNA was 1.11 and was nearly constant in all stocks. The G-C base ratio of kinetoplast/nucleus resulted in a grouping corresponding with the peanut agglutinin (PNA)- and wheat germ agglutinin (WGA)-type characteristics of the T. cruzi stocks. The discriminant analysis revealed relationships, in that each stock contained some trypanosomes with DNA fluorescence characteristics of common to at least one other stock. After chromomycin A3 staining, the mean hit rates for the classification into group 1 PNA and the WGA group were 99% and 96%, respectively, and the respective rates obtained after DAPI application were 84% and 94%.