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Entamoeba histolytica: a eukaryote with trypanothione metabolism instead of glutathione metabolism

1999; Wiley; Volume: 30; Issue: 1 Linguagem: Inglês

10.1111/j.1470-8744.1999.tb01158.x

1470-8744

Raúl N. Ondarza, Angélica Iturbe, Gerardo Hurtado, Elsa Tamayo, Mauricio A. Ondarza, Eva Hernández,

Pneumocystis jirovecii pneumonia detection and treatment

Entamoeba histolytica is a human pathogen that lacks the capacity to synthesize glutathione but can incorporate it, from the growth media or presumably from the human host, to form trypanothione [ N 1 , N 8 ‐bis(glutathionyl)‐spermidine conjugate]. This novel thiol compound has previously been found in trypanosomatids, as has its precursor glutathionyl‐spermidine, which was originally detected in Escherichia coli . Previously we showed the presence of these two thiol compounds in extracts from cultures of Entamoeba histolytica HK9. Here we report that when Entamoeba histolytica HK9 is grown in a culture medium that lacks glutathione (treated with the enzyme γ‐glutamyl transpeptidase), trypanothione is not formed, although the trophozoites can continue dividing for at least 60 h but at 25% lower cell density. The finding of a trypanothione metabolism in Entamoeba histolytica raises many questions: one concerns the possibility of a phylogenetic relationship, in this respect, with trypanosomatids such as Trypanosoma cruzi , T. brucei and Crithidia fasciculata ; another concerns its role in cell metabolism; a third concerns it possible use as a target for a rational drug design strategy against this parasite.