Variable related to the Trypanosoma cruzi (Chagas, 1909) and to the Triatoma brasiliensis vector (Neiva, 1911) that intervenes in the host-parasite relations / Variáveis relacionadas ao Trypanosoma cruzi (Chagas, 1909) e ao vetor Triatoma brasiliensis (Neiva, 1911) que interferem na interação parasito-hospedeiro

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

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 and in 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. brasiliensis were isolated, characterized and sequenced. Defensins belong to the cysteine-rich peptides group, presenting activity against Gram-positive bacteria and can be found in numerous insect species, mammals and plants. Lysozymes are also present in insects belonging to different orders, and in the genus Drosophila and Musca, can perform as digestive enzymes. The expression patterns of these antimicrobial peptides in different regions of the gut of T. brasiliensis were also evaluated, using in situ hybridization and real-time PCR.

ASSUNTO(S)

relações hospedeiro-parasita defensinas triatoma brasiliensis triatoma brasiliensi triatoma infecção trypanosoma cruzi defensins biologia geral triatoma muramidase host-parasite relations infection trypanosoma cruzi muramidase

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