Characterization and grouping ofTrypanosoma cruzi stocks by DNA base-specific fluorochromes and discriminant analysis

Abstract

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%.

Taxonomy of Trypanosoma cruzi: a commentary on characterization and nomenclature

“…While there are differences of opinion about the significance of this division (Brisse et al 1998, Souto et al 1998, Macedo & Pena 1998) the basis for the division is well supported (Table). The discovery that microbial lineages maintain their ge- Miles et al (1977) Strain-group 1 Strain-group 2 Miles et al (1978) Type 1 Type 2 Barret et al (1980) Zymodeme 1 Zymodeme 2 Romanha (1979) Zymodeme A Zymodeme B Ebert (1982) Group 1 Group 2 Schottelius (1982) Type 2 (PNA) Type 1 (WGA) Tibayrenc & Miles (1983) Braz ZI Braz Z2 Bol Z2 Zillman & Ebert (1983) Group A Group B Tibayrenc et al (1984) Isoenzyme strain (IS) 1 IS 2e IS 2 Miles et al (1984) Chilean Z1 Chilean Z2a Chilean Z2b Tibayrenc & Ayala (1988) Zymodeme 17 Zymodeme 30 Zymodeme 39 a Muhlpfordt & Berger (1990) DNA group 1 DNA group 2 Clark & Pung (1994) Ribodeme II Ribodeme I Tibayrenc (1995) Group I Group II Genotype 39 Souto et al (1996) Lineage II The Table presents the principal correlations among the many typing schemes proposed by various authors for classifying T. cruzi strains. As the techniques were applied on different collections of strains not all strains or isolates within each subdivision may exactly correspond in all of the studies.…”

Cytometry in Malaria—A Practical Replacement for Microscopy?

“…This dye combination was also used to identify different bacterial species by base composition and was shown to provide reliable quantification of A+T percentage. Such analyses do not demand use of high‐powered, high‐priced cell sorters; base composition differences between trypanosomal strains, which would be expected to yield roughly the same fluorescence intensities as would malaria parasites, can be detected on smears using relatively modest fluorescence imaging cytometry apparatus (Mühlpfordt et al, ; Mühlpfordt and Berger, , ).…”