Ma Jun, He Jun-Jun, Zhou Cheng-Yan, Sun Miao-Miao, Cevallos William, Sugiyama Hiromu, Zhu Xing-Quan, Calvopiña Manuel
State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China.
Carrera de Medicina, Facultad de Ciencias Médicas, Universidad Central del Ecuador, Quito, Ecuador.
Acta Trop. 2019 Jul;195:90-96. doi: 10.1016/j.actatropica.2019.04.025. Epub 2019 Apr 22.
Amphimerus Barker, 1911 is a liver fluke infecting several animal species and humans. Being a digenetic trematode of the Opisthorchiidae family, Amphimerus is closely related to the genera Metorchis, Clonorchis and Opisthorchis. Recently, a high prevalence of Amphimerus infection in humans, cats, and dogs had been demonstrated in a tropical Pacific region of Ecuador. Hence, we determined and characterized the entire mt genome sequences of adult liver flukes, morphologically identified as Amphimerus, collected in the endemic region of Ecuador, and examined its phylogenetic relationships with flukes in the Opisthorchiidae family using Bayesian inference (BI) based on the concatenated amino acid sequences and partial cox1 sequences. The complete mt genome sequence (15, 151 bp in length) of the Amphimerus sp. contains 35 genes, including 12 protein-coding genes (PCGs, without atp8), two rRNAs (rrnL and rrnS) and 21 tRNAs, lacking trnG. The gene content and arrangement of the Ecuadorian Amphimerus mt genome was similar to those of other trematodes in the Opisthorchiidae family. All genes in the circular mt genome of Amphimerus sp. are transcribed from the same strand in one direction, with the A + T content of 60.77%. Genetic distances between Amphimerus sp. and other genera in Opisthorchiidae were rather high, ranging from 26.86% to 28.75% at nucleotide level and 29.37%-31.12% at amino acid level. Phylogenetic analysis placed the Ecuadorian Amphimerus within the branch of Opisthorchiidae, but very distinct from Opisthorchis. Our results indicate that the liver fluke Amphimerus from Ecuador does not belong to the genus Opisthorchis, and that it should be assigned under the genus Amphimerus. The determination of the mt genome of the Ecuadorian Amphimerus provides a new genetic resource for future studies on taxonomy and molecular epidemiology of Opisthorchiidae trematodes.
1911年发现的巴克并殖吸虫是一种可感染多种动物及人类的肝吸虫。作为后睾科的双殖吸虫，并殖吸虫与后睾属、华支睾吸虫属及支睾吸虫属密切相关。近期，在厄瓜多尔一个热带太平洋地区已证实人类、猫和狗中并殖吸虫感染率很高。因此，我们测定并描述了在厄瓜多尔流行地区采集的形态学鉴定为并殖吸虫的成年肝吸虫的完整线粒体基因组序列，并基于串联氨基酸序列和部分细胞色素氧化酶亚基1（cox1）序列，采用贝叶斯推断（BI）研究其与后睾科吸虫的系统发育关系。并殖吸虫属物种的完整线粒体基因组序列（长度为15,151 bp）包含35个基因，包括12个蛋白质编码基因（PCGs，无atp8）、两个核糖体RNA（rrnL和rrnS）和21个转运RNA，缺少trnG。厄瓜多尔并殖吸虫线粒体基因组的基因内容和排列与后睾科其他吸虫相似。并殖吸虫属物种环状线粒体基因组中的所有基因均从同一条链以一个方向转录，A+T含量为60.77%。并殖吸虫属物种与后睾科其他属之间的遗传距离相当高，核苷酸水平为26.86%至28.75%，氨基酸水平为29.37%至31.12%。系统发育分析将厄瓜多尔并殖吸虫置于后睾科分支内，但与支睾吸虫属明显不同。我们的结果表明，来自厄瓜多尔的肝吸虫并殖吸虫不属于支睾吸虫属，应归为并殖吸虫属。厄瓜多尔并殖吸虫线粒体基因组的测定为今后后睾科吸虫的分类学和分子流行病学研究提供了新的遗传资源。
