INDUCTION OF TRYPANOSOMA-CRUZI METACYCLOGENESIS IN THE GUT OF THE HEMATOPHAGOUS INSECT VECTOR, RHODNIUS-PROLIXUS, BY HEMOGLOBIN AND PEPTIDES CARRYING ALPHA(D)-GLOBIN SEQUENCES

Induction of Trypanosoma cruzi metacyclogenesis in the gut of the hema tophagous insect vector, Rhodnius prolixus, by hemoglobin and peptides carrying alpha(D)-globin sequences. Experimental Parasitology 81, 255 -261. Trypanosoma cruzi, a protozoan responsible for the American tryp anosomiasis (Chagas disease), multiplies and differentiates in the gut of triatomine insect vectors. The effects of hemoglobin and synthetic peptides carrying alpha(D)-globin fragments on both the growth and th e transformation of T. cruzi epimastigotes (noninfective) into metacyc lic trypomastigotes (infective forms) were studied. This differentiati on in the insect's gut is expressed when hemoglobin and synthetic pept ides corresponding to residues 30-49 and 35-73 of the alpha(D)-globin were added to the plasma diet. However, synthetic peptide 41-73 does n ot induce differentiation of epimastigotes even in the presence of the two former synthetic peptides. Thus, these data delineate an unusual molecular mechanism which modulates the dynamics of transformation of epimastigotes into metacyclic trypomastigotes in the triatomine vector 's gut. (C) 1995 Academic Press, Inc.