Dvořáková Nela, Čepička Ivan, Qablan Moneeb A, Gibson Wendy, Blažek Radim, Široký Pavel
Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1/3, 612 42 Brno, Czech Republic; CEITEC-Central European Institute of Technology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1/3, 612 42 Brno, Czech Republic.
Department of Zoology, Faculty of Science, Charles University in Prague, Viničná 7, 120 44 Prague 2, Czech Republic.
Protist. 2015 Dec;166(6):599-608. doi: 10.1016/j.protis.2015.10.002. Epub 2015 Oct 19.
Little is known about host specificity, genetic diversity and phylogenetic relationships of African turtle trypanosomes. Using PCR targeting the SSU rRNA gene, we detected trypanosomes in 24 of 134 (17.9%) wild caught African pelomedusid turtles: Pelusios upembae (n=14), P. bechuanicus (n=1), P. rhodesianus (n=3) and P. subniger (n=6). Mixed infection of Trypanosoma species was confirmed by PCR in three specimens of P. upembae, and in one specimen each of P. bechuanicus, P. rhodesianus, and P. subniger. Microscopic examination of stained blood smears revealed two distinct forms (broad and slender) of trypomastigotes. The broad form coincided in morphology with T. mocambicumPienaar, 1962. Accordingly, we have designated this form as the neotype of T. mocambicum. In phylogenetic analysis of the SSU rRNA gene, all the new turtle trypanosome sequences grouped in a single clade within the strongly supported "aquatic" clade of Trypanosoma species. The turtle trypanosome clade was further subdivided into two subclades, which did not correlate with host turtle species or trypanosome morphology. This study provides the first sequence data of Trypanosoma species isolated from freshwater turtles from tropical Africa and extends knowledge on diversity of trypanosomes in the Afrotropical zoogeographical realm.
关于非洲龟类锥虫的宿主特异性、遗传多样性和系统发育关系，我们所知甚少。通过针对小亚基核糖体RNA（SSU rRNA）基因的聚合酶链式反应（PCR），我们在134只野生捕获的非洲侧颈龟中有24只（17.9%）检测到了锥虫，这些龟包括乌彭巴侧颈龟（Pelusios upembae，n = 14）、贝氏侧颈龟（P. bechuanicus，n = 1）、罗德西亚侧颈龟（P. rhodesianus，n = 3）和黑腹侧颈龟（P. subniger，n = 6）。通过PCR在3只乌彭巴侧颈龟标本中以及在各1只贝氏侧颈龟、罗德西亚侧颈龟和黑腹侧颈龟标本中证实了锥虫种类的混合感染。对染色血涂片的显微镜检查揭示了两种不同形态的锥鞭毛体（宽型和细长型）。宽型在形态上与1962年发现的莫桑比克锥虫（Trypanosoma mocambicum Pienaar）一致。因此，我们将这种形态指定为莫桑比克锥虫的新模式。在对SSU rRNA基因的系统发育分析中，所有新的龟类锥虫序列都聚集在锥虫物种的“水生”进化枝中一个得到有力支持的单系分支内。龟类锥虫分支进一步细分为两个亚分支，这与宿主龟的种类或锥虫形态无关。本研究提供了从热带非洲淡水龟分离出的锥虫物种的首批序列数据，并扩展了对非洲热带动物地理区域内锥虫多样性的认识。
