title: Aflagellar epimastigote forms are found in axenic culture of Trypanosoma caninum.
abstract: Representatives of the genus Trypanosoma have been traditionally found in epimastigote, espheromastigote and trypomastigote flagellated forms in axenic cultures. Trypanosoma caninum is a trypanosomatid that has recently been reported infecting dogs in endemic areas of canine leishmaniasis in Brazil. It presents specific biological characteristics and it is found exclusively on healthy skin. Here, we describe the evolutive forms of this parasite showing not only the forms commonly found in culture, but also epimastigote forms with no free flagellum. The study was conducted using scanning and transmission electron microscopy and, we demonstrate that typical flagellated epimastigotes originate from forms without flagellum, although the latter may remain without differentiation in the culture. Two hypotheses are considered and discussed in this paper: (i) the aflagellated epimastigotes are a typical developmental forms of T. caninum and (ii) the emergence of these aflagellated forms could be resultant from a disturbed process during cell division caused by interfering specific proteins, which leads to inability to form and regulate the flagellum length. In any case, considering that T. caninum is a parasite that is still little studied, the information brought by our study adds data which may be useful to clarify aspects on the cell cycle of this intriguing parasite that has been found in different regions of Brazil.
authors.affiliation: Programa de Pós-Graduação em Pesquisa Clínica em Doenças Infecciosas, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, Brazil.
authors.forename: Juliana H S
authors.initials: JH
authors.lastname: Barros
authors.affiliation: Laboratório de Vigilância em Leishmanioses, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, Brazil.
authors.forename: Tatiana S
authors.initials: TS
authors.lastname: Fonseca
authors.affiliation: Plataforma Multiusuários Rudolf Barth, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-360 Rio de Janeiro, Brazil.
authors.forename: Roger M
authors.initials: RM
authors.lastname: Macedo-Silva
authors.affiliation: Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-360 Rio de Janeiro, Brazil.
authors.forename: Suzana
authors.initials: S
authors.lastname: Côrte-Real
authors.affiliation: Laboratório de Diagnóstico Molecular e Hematologia, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, 21491-599 Rio de Janeiro, Brazil.
authors.forename: Helena K
authors.initials: HK
authors.lastname: Toma
authors.affiliation: Laboratório de Vigilância em Leishmanioses, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, Brazil. Electronic address: fatima.madeira@ipec.fiocruz.br.
authors.forename: Maria de Fatima
authors.initials: Mde F
authors.lastname: Madeira
mesh_terms: D000818:Animals; D061245:Axenic Culture; D001938:Brazil; D004285:Dogs; D005407:Flagella / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D014345:Trypanosoma / Q000254:growth & development* / Q000302:isolation & purification / Q000648:ultrastructure*
keywords: Dog; Electron microscopy; Light microscopy; Trypanosomatidae; Ultrastructure