摘要
目的 :测定蜱中单核细胞埃立克体的 16SrRNA全基因序列 ,鉴定病原菌。方法 :应用从16SrRNA基因构建的特异和通用引物进行PCR ,从越原蜱标本中分段扩增查菲埃立克体DNA ,进行克隆和序列测定 ;将其连成完整序列与埃立克体族中其他微生物进行同源性比较 ,并以相等数量定位碱基的核苷酸序列进行遗传发育分析。结果 :测定序列全长 146 3bp ,与美国查菲埃立克体分离株的 16SrRNA基因序列相差 6个核苷酸 ,同源性为 99.6 % ,遗传发育分析两者无明显差异 ;与犬埃立克体、尤氏埃立克体、小鼠埃立克体的同源性为 97.5%～ 98.0 % ,属于同一个基因群 ;与其他埃立克体种的同源性为 83.0 %～ 92 .9%。结论 :首次报道了我国南方蜱中埃立克体的 16SrRNA全序列 ,确定了其分类位置 。
Objective: To analyze the whole sequence of 16S rRNA gene of monocytic Ehrlichia in ticks in order to identify the pathogenic presence of the organism. Methods: Specific and universal primers derived from the 16S rRNA gene of Ehrlichia chaffeensis were used to amplify ehrlichial DNA in fractions from Haemaphysalis yeni ticks. The PCR products were cloned and sequenced. The whole nucleotide sequence was assembled from the fragments, and compared with other members of the tribe Ehrlichiae for maximal homology. The phylogenetic analysis was conducted using data of homologous sites where alignment of 16S rRNA gene sequence was unambiguous. Results: 1 463 bp nucleotide sequence was assembled, which differed in 6 positions from the 16S rRNA gene sequence of E.chaffeensis isolated from patient in the United States, with a similarity of 99.6%. Phylogenetic analysis did not show obvious difference between the two sequences. The homology with E.canis, E. ewingii and E.muris was from 97.5% to 98.0%,indicating that they belonged to the same genogroup according to the results of phylogenetic analysis,while the level of similarity with other members of the tribe Ehrlichiae ranged from 83.0% to 92.9% . Conclusion: This is the first report of identification of Ehrlichia in ticks based on the whole sequence of 16S rRNA gene. Further studies are required to investigate natural foci of monocytic ehrlichiosis in southern China. [
出处
《军事医学科学院院刊》
CSCD
北大核心
2000年第1期1-4,共4页
Bulletin of the Academy of Military Medical Sciences
基金
国家自然科学基金!(39970 655)
院科技创新启动基金
