Joachim A, von Samson-Himmelstjerna G
Institut für Parasitologie, Tierärztliche Hochschule Hannover, Germany. Baerbel.
Parasitol Res. 2001 Sep;87(9):764-7. doi: 10.1007/s004360100446.
Degenerated primers were used to amplify DNA fragments of the triosephosphate isomerase (TPI) gene from complementary DNA (cDNA) and from genomic DNA of two species of porcine gastrointestinal nematodes, Oesophagostomum dentatum and O.quadrispinulatum. Polymerase chain reaction (PCR) fragments amplified from cDNA were 520 bp in size for both species, while genomic fragments were 1,035 bp for O. dentatum (GC-content: 45%) and 1,331 bp for O. quadrispinulatum (44%). Sequence analyses revealed blocks of high homology in the exons interrupted by more variable parts in the intron regions. Five exons were predicted from the genomic sequences in the conserved regions which corresponded to the respective cDNA sequences with 6% interspecific differences. The predicted protein sequences (161 amino acids) were 98% similar between the species and showed 71% similarity to the putative protein of Caenorhabditis elegans. As a housekeeping gene, TPI could be amplified from cDNA of both infectious third-stage larvae and adults. Interspecific variations in the non-coding regions allow the PCR-based differentiation of the two Oesophagostomum spp.
使用简并引物从两种猪胃肠道线虫——齿状食道口线虫和四棘食道口线虫的互补DNA（cDNA）及基因组DNA中扩增磷酸丙糖异构酶（TPI）基因的DNA片段。从cDNA扩增得到的聚合酶链反应（PCR）片段，两种线虫均为520 bp，而从基因组扩增得到的片段，齿状食道口线虫为1035 bp（GC含量：45%），四棘食道口线虫为1331 bp（44%）。序列分析显示，外显子中有高度同源的区域，被内含子区域中更多可变部分隔开。从保守区域的基因组序列预测出5个外显子，这些外显子与各自的cDNA序列相对应，种间差异为6%。预测的蛋白质序列（161个氨基酸）在两种线虫之间相似度为98%，与秀丽隐杆线虫的假定蛋白质相似度为71%。作为一个管家基因，TPI可以从感染性第三期幼虫和成虫的cDNA中扩增出来。非编码区的种间变异使得基于PCR技术能够区分这两种食道口线虫。
