Molecular characterization of Fasciola spp. from the endemic area of northern Iran based on nuclear ribosomal DNA sequences
Molecular characterization of Fasciola spp. from the endemic area of northern Iran based on nuclear ribosomal DNA sequences
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DOI：
10.1016/j.exppara.2011.03.011
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发表时间：
2011-07-01
影响因子：
2.1
通讯作者：
Ben Slimane, Badreddine
中科院分区：
文献类型：
--
作者：
Amor, Nabil;Halajian, Ali;Ben Slimane, Badreddine
由片形吸虫（Platyhelminthes: Trematoda: Digenea）引起的片形吸虫病被认为是热带国家反刍动物最重要的寄生虫感染，造成了相当大的社会经济问题。在伊朗北部的流行地区，肝片吸虫和巨型片吸虫以前已经根据形态计量学差异进行了表征，但必须使用分子标记来准确区分物种和中间形式。对来自伊朗北部不同地区的水牛和山羊样本进行了形态鉴定，并对其核糖体DNA （rDNA）的第1段（ITS-1）和第2段（ITS-2）内转录间隔段（ITS）序列进行了遗传鉴定。将伊朗北部地区标本的ITS与GenBank中的片形吸虫序列进行比较，结果表明，所检标本的ITS序列与最常见的单倍型肝炎F. （n = 25, 48.1%）和巨型F. （n = 20, 38.45%）序列相同，但在ITS区域序列的不同可变核苷酸位置上存在差异，其中间形式（n = 7, 13.45%）在所有位置上都存在核苷酸重叠。来自水牛和山羊的片形吸虫分离株的ITS序列经历了渗入/杂交，正如先前报道的来自其他反刍动物和人类的分离株一样。根据ITS-1和ITS-2序列，吸虫分散在纯肝螺旋体中。巨型F.和中间片形吸虫枝，表明在伊朗北部，多种基因型的片形吸虫能够感染山羊和水牛。此外，基于ITS-1和ITS-2序列的系统发育树显示，伊朗样本与非洲和亚洲不同地区分离的肝螺旋体和巨型螺旋体有密切的关系。本研究显示，基因间转录间隔序列ITS-1和ITS-2为片形吸虫遗传分化提供了可靠的途径，为进一步研究亚洲流行区肝吸虫、巨型吸虫及其中间形态提供了基础。(C) 2011爱思唯尔公司版权所有。
Fasciolosis caused by Fasciola spp. (Platyhelminthes: Trematoda: Digenea) is considered as the most important helminth infection of ruminants in tropical countries, causing considerable socioeconomic problems. In the endemic regions of the North of Iran, Fasciola hepatica and Fasciola gigantica have been previously characterized on the basis of morphometric differences, but the use of molecular markers is necessary to distinguish exactly between species and intermediate forms. Samples from buffaloes and goats from different localities of northern Iran were identified morphologically and then genetically characterized by sequences of the first (ITS-1) and second (ITS-2) Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA (rDNA). Comparison of the ITS of the northern Iranian samples with sequences of Fasciola spp. from GenBank showed that the examined specimens had sequences identical to those of the most frequent haplotypes of F. hepatica (n = 25, 48.1%) and F. gigantica (n = 20, 38.45%), which differed from each other in different variable nucleotide positions of ITS region sequences, and their intermediate forms (n = 7, 13.45%), which had nucleotides overlapped between the two Fasciola species in all the positions. The ITS sequences from populations of Fasciola isolates in buffaloes and goats had experienced introgression/hybridization as previously reported in isolates from other ruminants and humans. Based on ITS-1 and ITS-2 sequences, flukes are scattered in pure F. hepatica. F. gigantica and intermediate Fasciola clades, revealing that multiple genotypes of Fasciola are able to infect goats and buffaloes in North of Iran. Furthermore, the phylogenetic trees based upon the ITS-1 and ITS-2 sequences showed a close relationship of the Iranian samples with isolates of F. hepatica and F. gigantica from different localities of Africa and Asia. In the present study, the intergenic transcribed spacers ITS-1 and ITS-2 showed to be reliable approaches for the genetic differentiation of Fasciola spp., providing bases for further studies on F. hepatica, F. gigantica and their intermediate forms in the endemic areas in Asia. (C) 2011 Elsevier Inc. All rights reserved.