Le T H, Pham K L T, Doan H T T, Le T K Xuyen, Nguyen K T, Lawton S P
Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam.
Graduate University of Science and Technology (GUST), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam.
J Helminthol. 2020 Mar 6;94:e136. doi: 10.1017/S0022149X20000164.
Many members of Fasciolidae are common trematodes in cattle, buffaloes, sheep, elephants, pigs, with some capable of infecting humans also. In this study, the complete or near-complete sequences of ribosomal transcription unit (rTU or rDNA), each of Fasciola hepatica (Australia), Fascioloides jacksoni (Sri Lanka), Fasciolopsis buski (Vietnam) and three isolates of F. gigantica (Vietnam), were obtained and characterized. The full length of rDNA for each F. hepatica, 'hybrid' Fasciola sp., Fas. jacksoni and Fa. Buski, was 7657 bp, 7966 bp, 7781 bp and 8361 bp, with the complete intergenic spacer region (IGS) (862 bp, 1170 bp, 987 bp and 561 bp), respectively. The rDNA of two 'pure' F. gigantica isolates from Vietnam was 6794 bp with unsequenced IGS. For 28S rRNA genes the Fasciola spp. are equal, 1958 bp for 18S, 160 bp for 5.8S, 3863 bp and 454 bp for ITS1 but ITS2 differ by one nucleotide (Thymine) (359 or 360 bp). The ITS1 of the sensu lato Fa. buski has some distinguishable features, 286 bp for ITS2, 3862 bp for 28S and four repeat units of 356-361 bp each found in ITS1. The 28S rDNA analysis showed the lowest level of divergence (0-0.57%) between F. hepatica and F. gigantica and higher (2.23-2.62%) and highest (6-6.42%) for Fas. jacksoni and Fasciolopsis, respectively. The tree of 43 strains/species clearly produced a well-supported phylogeny, where 18 fasciolids consistently grouped, forming a discrete Fasciolidae clade, distinct from Philophthalmidae, Echinostomatidae and Echinochasmidae in Echinostomatoidea. Fascioloides jacksoni is outside Fasciola spp.: basal with Fas. magna, as previously demonstrated.
片形科的许多成员是牛、水牛、绵羊、大象、猪体内常见的吸虫，有些也能感染人类。在本研究中，获得并鉴定了肝片吸虫（澳大利亚）、杰克逊并殖吸虫（斯里兰卡）、布氏姜片吸虫（越南）以及三种巨片吸虫分离株（越南）的核糖体转录单元（rTU或rDNA）的完整或近乎完整序列。每种肝片吸虫、“杂交”片形吸虫、杰克逊并殖吸虫和布氏姜片吸虫的rDNA全长分别为7657 bp、7966 bp、7781 bp和8361 bp，其完整的基因间隔区（IGS）分别为862 bp、1170 bp、987 bp和561 bp。来自越南的两种“纯”巨片吸虫分离株的rDNA为6794 bp，IGS未测序。对于28S rRNA基因，片形吸虫属的长度相同，18S为1958 bp，5.8S为160 bp，ITS1为3863 bp和454 bp，但ITS2相差一个核苷酸（胸腺嘧啶）（359或360 bp）。广义的布氏姜片吸虫的ITS1有一些可区分的特征，ITS2为286 bp，28S为3862 bp，ITS1中有四个重复单元，每个重复单元为356 - 361 bp。28S rDNA分析表明，肝片吸虫和巨片吸虫之间的差异水平最低（0 - 0.57%），而杰克逊并殖吸虫和姜片吸虫属之间的差异水平较高（2.23 - 2.62%）和最高（6 - 6.42%）。43个菌株/物种的树状图清楚地产生了一个得到充分支持的系统发育树，其中18种片形吸虫始终聚在一起，形成一个离散的片形科分支，与棘口总科中的嗜眼吸虫科、棘口吸虫科和棘隙吸虫科不同。杰克逊并殖吸虫在片形吸虫属之外：如先前所示，与巨片吸虫处于基部位置。
