Felipe S. Coelho
Acta Protozoologica, Volume 58, Issue 2, 2019, pp. 81-88
https://doi.org/10.4467/16890027AP.19.011.11420The protein profiles of the epimastigote stages from eight reference strains of Trypanosoma cruzi belonging to three different lineages (TcI, TcII and TcVI) were analyzed by SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis), under standardized conditions. More than 40 protein bands were observed in each strain. Around 55% of them were not shared by all stocks (non-conserved proteins), representing their intra-specific variability. Then, they were coded for processing by numerical taxonomy, using three association coefficients and the UPGMA clustering algorithm. With all coefficients assayed, two major groups were clearly seen, confirming the dichotomy within T. cruzi taxon, as demonstrated by other molecular and biochemical approaches. In the present study, the term peptideme was used to name the groups of strains based on their polypeptide profiles, following the above-cited methodology. Then, two major peptidemes were identified, each one presenting subdivisions. The isolates identified as TcI clustered in the same major peptideme, displaying a subgroup with the opossum isolates (G, SC28, Dm28c) apart from the stock of human origin (Colombian strain). The other major peptideme also showed two subgroups, regardless the coefficient used. One of them included the TcII strains (Y, SF21), both from Brazilian patients, and the other the TcVI stocks, both originally from triatomines from Southern Brazil (CL Brener, FL). As far we know, this is the first report on the parity between the T. cruzi lineages consensually accepted and their grouping into peptidemes based on SDS-PAGE and the numerical analysis of non-conserved proteins.