Su X, Zhang Y, Zheng X, Wang X X, Li Y, Li Q, Wang C R
College of Animal Science and Veterinary Medicine,Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
J Helminthol. 2018 Jul;92(4):484-490. doi: 10.1017/S0022149X17000554. Epub 2017 Jun 27.
Eurytrema pancreaticum is one of the most common trematodes of cattle and sheep, and also infects humans occasionally, causing great economic losses and medical costs. In this study, the sequences of the complete nuclear ribosomal DNA (rDNA) repeat units of five E. pancreaticum individuals were determined for the first time. They were 8306-8310 bp in length, including the small subunit (18S) rDNA, internal transcribed spacer 1 (ITS1), 5.8S rDNA, internal transcribed spacer 2 (ITS2), large subunit (28S) rDNA and intergenic spacer (IGS). There were no length variations in any of the investigated 18S (1996 bp), ITS1 (1103 bp), 5.8S (160 bp), ITS2 (231 bp) or 28S (3669 bp) rDNA sequences, whereas the IGS rDNA sequences of E. pancreaticum had a 4-bp length variation, ranging from 1147 to 1151 bp. The intraspecific variations within E. pancreaticum were 0-0.2% for 18S rDNA, 0-0.5% for ITS1, 0% for 5.8S rDNA and ITS2, 0-0.2% for 28S rDNA and 2.9-20.2% for IGS. There were nine types of repeat sequences in ITS1, two types in 28S rDNA, but none in IGS. A phylogenetic analysis based on the 18S rDNA sequences classified E. pancreaticum in the family Dicrocoeliidae of Plagiorchiata, closely related to the suborder Opisthorchiata. These results provide useful information for the further study of Dicrocoeliidae trematodes.
胰阔盘吸虫是牛羊最常见的吸虫之一，偶尔也会感染人类，造成巨大的经济损失和医疗费用。在本研究中，首次测定了5个胰阔盘吸虫个体的完整核糖体DNA（rDNA）重复单元序列。它们的长度为8306 - 8310 bp，包括小亚基（18S）rDNA、内转录间隔区1（ITS1）、5.8S rDNA、内转录间隔区2（ITS2）、大亚基（28S）rDNA和基因间隔区（IGS）。所研究的18S（1996 bp）、ITS1（1103 bp）、5.8S（160 bp）、ITS2（231 bp）或28S（3669 bp）rDNA序列均无长度变异，而胰阔盘吸虫的IGS rDNA序列有4 bp的长度变异，范围为1147至1151 bp。胰阔盘吸虫种内18S rDNA的变异为0 - 0.2%，ITS1为0 - 0.5%，5.8S rDNA和ITS2为0%，28S rDNA为0 - 0.2%，IGS为2.9 - 20.2%。ITS1中有9种重复序列类型，28S rDNA中有2种，而IGS中没有。基于18S rDNA序列的系统发育分析将胰阔盘吸虫归类于斜睾目双腔科，与后睾亚目关系密切。这些结果为进一步研究双腔科吸虫提供了有用信息。
