不同地理株间日疟原虫环子孢子蛋白基因多态性的特征

CHARACTERISTICS OF POLYMORPHISM OF CIRCUMSPOROZOITE PROTEIN GENE OF PLASMODIUM VIVAX OF DIFFERENT GEOGRAPHICAL STRAINS 

目的：探讨间日疟原虫环子孢子蛋白（ＣＳＰ）基因多态性的地理特征及其实用意义。方法：用ＤＮＡ的ＰＣＲ扩增与电泳切带纯化法，获得所研究的基因片段；用引物标记周期反应测序法，测定ＤＮＡ序列；用图解法分析比较各地ＣＳＰ基因的氨基酸序列的变化。结果：所测定的中国、菲律宾和所罗门的１５个间日疟分离株均属ＰＶ－１型，但各株有较明显的地理性变异。６个中国株与ＮＫ株相似，其中Ｃ－２与ＮＫ株完全一致，而与其他Ⅰ型株有明显区别。结论：根据ＣＳＰ基因中央重复区及重复后可变区推导的氨基酸序列的变异情况，在Ｑａｒｉｔ和Ｍａｎｎ的分组基础上，迄今已发表的所有Ⅰ型株可归纳为２族６个组。分组序列特征有可能用于不同地理株的检出和鉴定，从而在疟疾的流行病学与防治上有实用价值，并将有助于疟原虫的生物学、分类学和种系发生的研究。

AIM: To explore the polymorphism of circumsporozoite protein (CSP) genes of different geographic strains of Plasmodium vivax and its significance. METHOD: PCR amplification and electrophoresis excised purification was used to obtain the studied DNA fragments. Dye primer cycle sequencing was used to sequence the CSP genes. A schematic diagram method was employed to compare and analyse the sequence deviation. RESULTS: All obtained CSP gene sequences of the 15 isolates from China, Philippines and Solomon Islands are P.vivax type I in which some geographic deviations have been found. Six Chinese isolates were similar to NK isolate and one of them, C 2, was identical to NK isolate and remarkably distinct from all other type I isolates. CONCLUSION: Based on the sequence deviation at amino acid level of CSP genes from different parts in the world and on Qarits and Manns grouping, all of type I isolates published so far can be categorized into 2 families including 6 groups. The grouped sequence characteristics might be used to develop a rapid and practical method for the detection and identification of different geographic strains which could be of significance in malaria epidemiology and control, and be useful in the research of biology, taxonomy and phylogenetic of this parasite.