Variable related to the Trypanosoma cruzi (Chagas, 1909) and to the Triatoma brasiliensis vector (Neiva, 1911) that intervenes in the host-parasite relations

by Chaves de, Catarina Andréa

Abstract (Summary)
Despite of the multiclonal structure and genetical variability of Trypanosoma cruzi (Chagas, 1909), several investigations using the eletrophoretic profiles(zymodeme) and molecular techniques were used to characterize subpopulations of this parasite, further defining two main distinct and distant phylogenetic lineages: T. cruzi (TcI and TcII). In the present work, the first topic investigated was the differentiation of the main subpopulations of T. cruzi (TcI and TcII) in vitro using lectins as biochemical marker. To understand the behaviour of the two main lineages of T. cruzi in a concomitant infection, kinetic growth in axenic medium andin the digestive tract of Triatoma brasiliensis (Naiva, 1911) were done. The second part of our work was to investigate the defense mechanisms of T. brasiliensis,knowing that insects synthesize several antimicrobial peptides, when infected by bacteria or other pathogen. In addition, these antimicrobial peptides are compounds which exhibit activity against Gram-positive and Gram-negative bacteria. For this, genes which encoding defensins and lysozyme from the midgut of T. brasiliensiswere isolated, characterized and sequenced. Defensins belong to the cysteine-rich peptides group, presenting activity against Gram-positive bacteria and can be foundin numerous insect species, mammals and plants. Lysozymes are also present in insects belonging to different orders, and in the genus Drosophila and Musca, canperform as digestive enzymes. The expression patterns of these antimicrobial peptides in different regions of the gut of T. brasiliensis were also evaluated, usingin situ hybridization and real-time PCR.
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Ana Maria Jansen-Franken

School:Faculdades Oswaldo Cruz

School Location:Brazil

Source Type:Master's Thesis

Keywords:Triatoma Trypanosoma cruzi Defensinas Muramidase brasiliensis Infection Defensins brasiliensi Host-Parasite Relations


Date of Publication:08/31/2006

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