猪胞内劳森菌16SrRNA基因的克隆及序列分析

Cloning and sequencing analysis of 16SrRNA gene of Lawsonia intracellularis

胞内劳森菌（Lawsonia intracellularis,LI）是猪增生性肠炎的病原,本试验设计3条引物,采用半巢式PCR,从猪的回肠粘膜中扩增出长为1 457 bp的胞内劳森氏菌16SrRNA基因,并进行序列比较分析。结果表明,与不同动物源性（鼠、仓鼠、鹿、马、鸵鸟等）的增生性肠炎胞内菌核苷酸同源性在98.4%-100%之间,与脱硫弧菌同源性达到88.6%,与一般弯曲杆菌和螺旋体同源性较低（71.8%-73.9%）。

Lazvsonia intracellularis （LI）is a newly discovered etiological agent,which causes porcine proliferative enteropathy that cuts down feed conversion rate and threatens hog industry seriously. However,there is a lack of reports on sequencing analysis of this etiological agent gene in domestic. In this study, we designed 3 primers to amplificate LI 16SrRNA gene consisted of 1 457 bp,through semi-nested PCR,and then made sequence analysis. The result showed that the isolate from this study had 98.4% to 100% nucleotide sequence homology with the isolates from other species of anmals （such as mouse,hamster,deer,horse and ostrich etc. ） ,88.6% homology with D. desulfuricans,and low homology （from 71.8% to 73.9%） with Campylobacter species and Spirochaeta. It is a first report on the gene clone and sequence analysis of 16SrRNA gene of Lawsonia intracellularis in domestic,and gives a reference basis to the molecular diagnostic methods and classification for this etiological agent.