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Isoenzymatic Characterization of Colombian Strains of Trypanosoma cruzi


Isoenzymatic Characterization of Colombian Strains of Trypanosoma cruzi

Vol. 93(6): 739-740

P Rodríguez, M Montilla*, S Nicholls*, I Zarante**, C Puerta/+

Laboratorio de Parasitología Molecular, Departamento de Microbiología, Facultad de Ciencias, Universidad Javeriana, Carrera 7 No. 43-82, Ed. Felix Restrepo, Of.111, Santafé de Bogotá, Colombia *Laboratorio de Parasitología, Instituto Nacional de Salud, Av. El Dorado con Carrera 50, Santafé de Bogotá, Colombia **Instituto de Genética, Facultad de Medicina, Universidad Javeriana, Carrera 7 No. 40-62, Santafé de Bogotá, Colombia

Key words: isoenzymes - Trypanosoma cruzi - variability


Trypanosoma cruzi, the causative agent of Chagas' disease is a highly pleomorphic parasite with a complex life cycle involving both a vertebrate host and an invertebrate vector. Several studies have been done because of its large biological and genetic variability (M Pereira & R Hoff 1986 Mol Biochem Parasitol 20: 183-189, M Tibayrenc & F Ayala 1988 Evolution 4: 277-292). One of the methods that has been widely used for characterization of T. cruzi strains is isoenzyme analysis. P Ready and M Miles (1980 Trans R Soc Trop Med Hyg 74: 238-242) and M Miles et al. (1980 Trans R Soc Trop Med Hyg 74: 221-237) defined three zymodemes termed I (Z1), II (Z2) and III (Z3), based on Brazilian strains.

In the present study we have analyzed the isoenzyme profiles of seven T. cruzi strains from Colombia (Table I) according to the method described by S Abderrazak et al. (1993 Meth Mol Biol 21: 361-368) modified by M Montilla (1997 Biomédica 17: 125-126). The 13 enzymatic systems employed were Glucose phosphate isomerase (E.C. GPI), Glucose-6-phosphate dehydrogenase (E.C. G6PD), Isocitrate dehydrogenase (E.C. IDH), Malate dehydrogenase (E.C. MDH), Malic enzyme (E.C. ME-1, ME-2), Peptidase (E.C. PE-1, PE-1,2), 6-phosphogluconate dehydrogenase (E.C. 6PGD), Aspartate aminotransferase (E.C. ASAT), Glutamate dehydrogenase (NAD/NADP) (E.C. GDH), and Phosphoglucomutase (E.C. PGM).

In spite of the fact that polymorphism was observed in 8 out of the 11 enzymatic systems analyzed in the T. cruzi strains (Table II), the dendrogram based on Nei's genetic distances (1972 Am Nat 106: 283-292), showed that all the strains conform only one cluster (Fig.) irrespective of their geographic origin. These results are suggestive of ancient establishment of a population heterogeneity of the parasite in Colombia or of a significant circulation of the invertebrate and/or vertebrate host of T. cruzi between the studied areas (Table I).

In addition, comparison with isoenzyme profiles of T. cruzi Colombian strains previously typed (G Widmer et al. 1985 Ann Trop Med Parasitol 79: 253-257, N Saravia et al. 1987 Am J Trop Med Hyg 36 : 59-69, B Travi et al. 1994 Am J Trop Med Hyg 50: 557-565) indicates that all the strains analyzed in the present study belong to zymodeme Z1. Since these isolates were obtained from sylvatic and domestic environments of different geographic regions, the association of zymodeme Z1 to both transmission cycles in Colombia is concluded. Previous reports also indicated the presence of Z1 in domestic and sylvatic environments in some regions in Brazil (T Barret et al. 1980 Trans R Soc Trop Med Hyg 74: 84-90).

Finally, in this study we observed the change of the isoenzyme profile of BM López strain after consecutive in vitro passages during three years for the enzymes: GPI, PEP-1, GDHNAD and 6PGDH. This in vitro variability has been previously reported for other T. cruzi strains (A Alves et al. 1994 J Eukaryot Microbiol 41: 415-419).

+Corresponding author. Fax: +57-12-850503. E-mail:

Received 18 December 1997

Accepted 4 September 1998

Publication Dates

  • Publication in this collection
    08 Jan 1999
  • Date of issue
    Nov 1998
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