Laboratório de Protozoologia, Programa de Pós-graduação em Biodiversidade e Conservação da Natureza, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.
Instituto de Recursos Naturais, Universidade Federal de Itajubá, Itajubá, Minas Gerais, Brazil.
Parasitol Res. 2020 Aug;119(8):2597-2608. doi: 10.1007/s00436-020-06741-0. Epub 2020 Jun 30.
Trichodinid ciliates were isolated from calanoid copepods and were characterized by morphological and molecular techniques. The trichodinids found in this study were morphologically similar to Trichodina acuta, but morphometric differences were observed between our specimens and T. acuta. The T. acuta specimens, isolated from fish in several geographical locations around the world, were slightly larger than specimens in our population. In fact, our morphological and morphometric data are more similar to Trichodina diaptomi populations, also found on copepods. Moreover, our phylogenetic analyses revealed that the 18S rRNA gene sequence from our samples emerged in a clade with two T. acuta sequences, infesting fish hosts in China. These three sequences showed 100% identity. Our data, along with a taxonomic review, suggest that the species T. diaptomi, described recently, is actually a synonym of T. acuta and that this species may be related to fish and copepod hosts. In conclusion, we highlight the urgent need to better investigate the polymorphism and host specificity within the Mobilida, as this data may represent important characters to better understand the evolution into this order.
纤毛虫从哲水蚤中分离出来，并通过形态学和分子技术进行了特征描述。本研究中发现的纤毛虫在形态上与旋口虫（Trichodina acuta）相似，但我们的标本与 T. acuta 之间存在形态差异。从世界上几个不同地理位置的鱼类中分离出的 T. acuta 标本比我们种群中的标本稍大。事实上，我们的形态学和形态计量学数据与也在哲水蚤上发现的 Diaptominae 种群的旋口虫更为相似。此外，我们的系统发育分析表明，我们样本的 18S rRNA 基因序列与来自中国鱼类宿主的两种 T. acuta 序列在一个分支中出现。这三个序列完全一致。我们的数据以及分类学综述表明，最近描述的物种 T. diaptomi 实际上是 T. acuta 的同义词，并且该物种可能与鱼类和哲水蚤宿主有关。总之，我们强调迫切需要更好地研究 Mobilida 内的多态性和宿主特异性，因为这些数据可能代表着更好地理解该目进化的重要特征。
