Estudo morfológico, biológico e caracterização molecular de duas novas espécies de Trypanosoma oriundos de carrapatos naturalmente infectados

Abstract

Parasites of the genus Trypanosoma are unicellular and flagellated microorganisms from the Trypanosomatidae family. This study describes for the first time the encounter of two isolates of the Trypanosoma genus naturally infecting Rhipicephalus microplus and Amblyomma brasiliense characterized through molecular, morphological and biological analyzes. Trypanosoma cultures were obtained by isolation in IDE8 cell lines and maintained in L15B culture environment, incubated at 30°C. The isolates obtained had a good yield spread in an L15B environment at temperatures of 30oC, 32ºC and 34ºC. The culture remained stable over 14 spread passages in axenic culture in L15B environment at a temperature of 30°C. Cryopreservation of the isolated culture presented viability after thawing due to liquid nitrogen storage. The curve of growth and analysis of the evolutionary forms of the isolates in the axenic environment and the cell lines IDE8 and DH82 were performed. The analysis of nucleotide sequences obtained with goals directed at the region 18S rDNA and 24Sα rDNA confirmed the authenticity of this new species. The nucleotide sequences described were deposited to Genbank. Scanning electron microscopy and morphometric analysis revealed a wide morphological diversity of the two described species. Flow cytometry associated with fluorescence microscopy confirmed the internalization of both Trypanosomatid isolates in cells from the IDE8 and DH82 lines even with the inhibition of cellular phagocytosis. Pathogenicity-related aspects, involvement in vertebrate hosts, epidemiology, evolutionary cycle and transmission mechanisms are still unknown. Therefore, more studies will be necessary for the knowledge of life cycle aspects of Trypanosoma rhipicephalis sp. nov. and Trypanosoma amblyommi sp. nov.