Differences in binding of lectin-gold conjugates by Trypanosoma cruzi and Blastocrithidia triatomae (Trypanosomatidae) in the intestine of Triatoma infestans (Reduviidae).

Two species of trypanosomatid flagellates, Trypanosoma cruzi and Blastocrithidia triatomae which develop in the intestine of Triatoma infestans, were incubated with lectin-gold conjugates to demonstrate sugar components of the cell surface with the electron microscope. T. cruzi, strain "Chile 5" (zymodeme 1), bound SBA-gold, revealing N-acetyl-galactosamine and/or galactose residues. WGA-BSA-gold, specific for N-acetylglucosamine, did not bind to the surface of this flagellate. On the other hand, N-acetyl-glucosamine bound WGA-BSA-gold on the cell membrane of epimastigotes and cysts of B. triatomae, whereas SBA-gold was not bound by flagellates which were attached to the midgut epithelium and the rectum cuticle. Among other criteria, these differences in lectin binding may facilitate the discrimination of the two parasite species in the vector of Chagas' disease.