斑点热群立克次体中国分离株rOmpA基因片段的克隆和序列分析

用Rr190.70p-602n引物扩增了斑点热群立克次体（spottedfevergrouprickettsiae，SFGR）中国分离株（BJ－90株、Ha－91株和HLJ－054株）及SFGR国际标准株西伯利亚立克次体（Rickettsiasibiricu）246株和派克立克次体（R.parkeri）的rOmpA基因片段，将PCR产物克隆入pGEM－T载体中，用双脱氧法进行序列测定，并与SFGR的rOmpA基因已知序列进行了比较。结果表明，SFGR国际标准株间rOmpA基因片段的核苷酸同源性为90.06%～96.62%，推定氨基酸的同源性为83.05％～94.35％，中国分离株与国际标准株及参考株rOmpA基因片段比较的结果发现：BJ－90株及Ha－91株与西伯利亚立克次体标准株的核苷酸同源性分别为99．06％和98．31％，推定氨基酸的同源性则为98.87％和96.61％，HL－93株和HLJ-054株与日本立克次体（R.japonica）核苷酸同源性较高，分别为96.62％和95.68％，推定氨基酸的同源性为92．09％和89．27％。在中国分离株内，BJ-90株和Ha－91株的核昔酸同源性高达99．2…

CLONING AND SEQUENCE ANALYSIS OF rOmpA GENE FRAGMENT OF SPOTTED FEVER GROUP RICKETTSIAE ISOLATED IN CHINA

Rr 190.70p-602n primers were used to amplify the rOmpA gene fragment of prototype strains (Rickettsia sibirica 246 strain and R parkeri) and Chinese strains (BJ-90, Ha-91 and HLJ-054) of spotted fever group rickettsiae (SFGR). The PCR products were cloned into pGEM-T vector respectively and sequenced by Sanger's dideoxy method. The sequences of the tested strains were compared with the corresponding regions of prototype and reference strains of SFGR. The results showed that the homology of rOmpA gene fragments of prototype strains varied from 90.06%-96.62% in nucleotide and 83.05%-94.35% in putative amino acid respectively.Compared Chinese strains with prototype and reference strains of SFGR. it was found that the homology of BJ-90 stain and Ha-91 strain with R sibirica 246 stain was the highest in nucleotide (99.06% and 98.31%, respectively) and in putative amino acid (98.87% and 96.61%, respectively), whereas HL-93 strain and HLJ-054 strain showed higher homology with R japonica (96.62% and 95.68% in nucleotide,respectively) than others. Among all the Chinese stains, the homology between BJ-90 strain and Ha-91 strain was the highest 99.25% in uncleotide and 97.74% in Putative amino acid. The homology of nucleotide and putative amino acid between HL-93 strain and HLJ-054 stain was 98.12% and 94.92% respectively. The above resultsindicated that all SFGR so far isolated from different scarces seem to be identical or closely related to R sibirica, except for HL-93 and HLJ-54 strains, which could be considered as new members of SFGR.