Resumo

Strigomonas culicis, a monoxenic kinetoplastid belonging to the Trypanosomatidae family, presents a symbiontic relationship with a bacteria that lives in its cytoplasm. Although integrated into the physiology of the parasite, the bacteria can be removed by antibiotic treatment, originating an aposymbiontic strain. Comparisons between the wild and aposymbiontic strains are an interesting strategy to identify metabolic pathways shared by the symbiont and its host, bringing more information about this sophisticated interrelationship. Furthermore, it can also contribute to a better understanding of the evolutionary process involved in the origin of new organelles. In this work, we performed a comparative analysis of the proteome of S. culicis wild strain and the aposymbiontic strain. The experimental setup consisted of two-dimensional gel electrophoresis followed by in gel digestion of proteins with trypsin and MALDI-TOF/TOF protein identification by peptide mass fingerprinting. After determining different stages of cell development, initial, middle and end of exponential phase were selected to proceed with proteomics approach. Quintuplicate 2D electrophoresis was performed for each of the selected stages, and image analysis was conducted to determine spots that shifted abundance across cell development between the strains. A total of 1421 spots were identified, by image analysis, as differentially expressed between the growth stages, among these are spots that are presented in more than one growth stage and spots that are exclusively presented in a specific growth stage of a strain, confirming significant differences between the strains. All spots are being analyzed by mass spectrometry. Further analyses are being performed in order to expand the number of protein identifications and create a panel for strain comparison.