Barros Juliana H S, Fonseca Tatiana S, Macedo-Silva Roger M, Côrte-Real Suzana, Toma Helena K, Madeira Maria de Fatima
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.
Laboratório de Vigilância em Leishmanioses, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, Brazil.
Acta Trop. 2014 Sep;137:147-51. doi: 10.1016/j.actatropica.2014.05.013. Epub 2014 May 29.
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.
传统上，在无细胞培养中发现锥虫属的代表呈现出上鞭毛体、球鞭毛体和锥鞭毛体等鞭毛形态。犬锥虫是一种锥虫，最近有报道称其在巴西犬利什曼病流行地区感染犬类。它具有特定的生物学特性，仅在健康皮肤中发现。在此，我们描述了这种寄生虫的进化形态，不仅展示了培养中常见的形态，还展示了没有游离鞭毛的上鞭毛体形态。该研究使用扫描电子显微镜和透射电子显微镜进行，我们证明典型的有鞭毛上鞭毛体起源于无鞭毛的形态，尽管后者在培养中可能保持未分化状态。本文考虑并讨论了两种假设：（i）无鞭毛上鞭毛体是犬锥虫的典型发育形态；（ii）这些无鞭毛形态的出现可能是由于特定干扰蛋白导致细胞分裂过程受到干扰，从而导致无法形成和调节鞭毛长度。无论如何，鉴于犬锥虫是一种仍未得到充分研究的寄生虫，我们的研究提供的信息增加了数据，可能有助于阐明这种在巴西不同地区发现的有趣寄生虫细胞周期的相关方面。
