实验室保存的恙虫病东方体Karp株与福建省分离株的sta56基因的序列分析

Sequence analysis of the sta 56 genes from the laboratory-preserved and the isolated strains from Fujian province of Orientia tsutsugamushi Karp strain

目的比较实验室保存的恙虫病东方体Karp株、福建省两个分离株的sta 56基因序列的差异。方法提取感染各株恙虫病东方体的Vero细胞的DNA,扩增出sta56的ORF。对不同株的ORF进行测序,对15株恙虫病东方体的sta56构建进化树并进行分析。结果实验室保存的Karp株的sta56基因序列有98%与参考株一致;FQ株和NA株仅有两个碱基的差异,有96%的序列与Karp株一致。结论实验室保存的Karp株sta56基因在长期传代中可发生变异,FQ株和NA株均属于Karp株。

To compare the differences in sequences of the, sta 56 gene of the laboratory-preserved and two isolated strains from Fujian province, the genomic DNAs of different strains of Qrientia tsutsugamushi were extracted from the infected Vero cells, and their open reading frames （ORF） of the sta 56 gene were amplified and sequenced. Phylogenetic tree was constructed on the sta 56 gene of 15 strains. It was found that the sequences of the sta 56 genes of long term-preserved Karp strain showed 98 % of identity with that of the reference strain. There were only two different nucleotides detected between the sequences of two locally isolated strains FQ and NA strain, showing 96 % of consensus sequences with Karp strain. These results indicates that the sta 56 gene of the long term-preserved Karp strain has undergone some variations after numerous passages, and the two locally isolated strains, FQ and NA strain, showing sequence variations are belong to the Karp strain.