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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060 EISSN: 1678-8060
Vol. 113, No. 1, 2018, pp. 1-11
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Bioline Code: oc18008
Full paper language: English
Document type: Research Article
Document available free of charge
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Memórias do Instituto Oswaldo Cruz, Vol. 113, No. 1, 2018, pp. 1-11
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Trypanosoma janseni n. sp. (Trypanosomatida: Trypanosomatidae) isolated from Didelphis aurita (Mammalia: Didelphidae) in the Atlantic Rainforest of Rio de Janeiro, Brazil: integrative taxonomy and phylogeography within the Trypanosoma cruzi clade
Lopes, Camila Madeira Tavares; Menna-Barreto, Rubem Figueiredo Sadok; Pavan, Márcio Galvão; Pereira, Mirian Cláudia de Souza & Roque, André Luiz R
Abstract
BACKGROUND Didelphis spp. are a South American marsupial species that are among the most ancient hosts for the Trypanosoma spp.
OBJECTIVES We characterise a new species (Trypanosoma janseni n. sp.) isolated from the spleen and liver tissues of Didelphis
aurita in the Atlantic Rainforest of Rio de Janeiro, Brazil.
METHODS The parasites were isolated and a growth curve was performed in NNN and Schneider’s media containing 10% foetal
bovine serum. Parasite morphology was evaluated via light microscopy on Giemsa-stained culture smears, as well as scanning
and transmission electron microscopy. Molecular taxonomy was based on a partial region (737-bp) of the small subunit (18S)
ribosomal RNA gene and 708 bp of the nuclear marker, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH)
genes. Maximum likelihood and Bayesian inference methods were used to perform a species coalescent analysis and to generate
individual and concatenated gene trees. Divergence times among species that belong to the T. cruzi clade were also inferred.
FINDINGS In vitro growth curves demonstrated a very short log phase, achieving a maximum growth rate at day 3 followed by a
sharp decline. Only epimastigote forms were observed under light and scanning microscopy. Transmission electron microscopy
analysis showed structures typical to Trypanosoma spp., except one structure that presented as single-membraned, usually
grouped in stacks of three or four. Phylogeography analyses confirmed the distinct species status of T. janseni n. sp. within the T. cruzi clade. Trypanosoma janseni n. sp. clusters with
T. wauwau
in a well-supported clade, which is exclusive and monophyletic.
The separation of the South American T. wauwau + T. janseni coincides with the separation of the Southern Super Continent.
CONCLUSIONS This clade is a sister group of the trypanosomes found in Australian marsupials and its discovery sheds light on
the initial diversification process based on what we currently know about the T. cruzi clade.
Keywords
Trypanosoma janseni; Didelphis aurita; biological characterisation; integrative taxonomy; phylogeography
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