Comparative Two-Dimensional Gel Electrophoresis of Trypanosoma cruzi Mammalian-Stage Forms in an Alkaline pH Range

It is estimated that several million people are currently infected worldwide by the protozoan parasite, Trypanosoma cruzi, which causes Chagas disease. After mammalian host infection, a fundamental event is the differentiation from infective trypomastigotes into replicative amastigotes (amastigogenesis) inside host-cells. To unravel the particularities of both forms, it is essential to identify molecules presented in each form. Since T. cruzi gene expression regulation occurs mainly at posttranscriptional level, a proteomic approach is appropriate. Due to intrinsic difficulties with performing 2-DE in the alkaline pH range, there are no reports on 2-DE-based comparative proteome analysis of T. cruzi mammalianstage forms that focus on alkaline polypeptides. Here, we performed a comparative proteome analysis between tissue culture- derived trypomastigotes and extracellular amastigote-like cells using conditions optimized for the 6-11 pH range followed by identification by MALDI-TOF/TOF technology. The alkaline 2-DE maps from both forms show that proteins with a pI above 7.0 were not underrepresented (= 65% of proteins detected). Moreover the differences in protein expression between the Human-hosted T. cruzi forms corroborated previous proteomic studies and corresponded to their biological traits.