TRYPANOSOMA-CRUZI - INHIBITION OF METACYCLOGENESIS BY MANNOSE

Metacyclogenesis of Trypanosoma cruzi epimastigotes was evaluated in a medium supplemented with Triatoma infestans intestinal homogenate in the presence of sugars and derivates as are mannose, galactose, fucose, N-acetylglucosamine, mannose 6-P, and fructose 1,6-P at a concentration of 25 mM. Only mannose significatively inhibited metacyclogenesis. Sodium metaperiodate and trypsin treatment of the intestinal homogenate also inhibited differentiation. In our opinion there exists a proteinic factor in the intestin of the vector that promotes metacyclogenesis and is incorporated by the parasite. Treatment of the intestinal homogenate with alkaline phosphatase had no effect. Instead, high ionic strength in the medium (0.4 M NaCl) strongly inhibited metacyclogenesis indicating that, in these conditions, the possible binding of the differentiation factor to the parasite surface was inhibited. © 1992 Academic Press, Inc.