蓝氏贾第鞭毛虫基因分型—磷酸丙糖异构酶(tim)基因序列分析

GENOTYPE IDENTIFICATION OF GIARDIA LAMBLIA:ANALYSIS OF THE TRIOSE PHOSPHATE ISOMERASE (TIM) GENE SEQUENCE

蓝氏贾第鞭毛虫（简称贾第虫）细胞内的磷酸丙糖异构酶（ｔｉｍ）基因编码磷酸丙糖异构酶。对扩增后的ｔｉｍ基因做序列分析，可对来源于不同地理位置和／或不同宿主的贾第虫株进行基因分型，并以此确定它们之间的遗传学关系。为了确定中国虫株的基因型，我们对分离自北京（Ｃ１），四川（Ｃ２）和福建（Ｃ３）３株人源贾第虫ｔｉｍ基因序列进行了分析。结果表明，Ｃ１和Ｃ２具有相同的遗传学特性，可划归为目前公认的分型系统中的第３型（ＧＳ）。Ｃ３含有两种不同的遗传学类型，即第１型（ＷＢ）和第３型（ＧＳ），表明Ｃ３可能为两种不同遗传学类型的混合株。本研究结果进一步表明，用ｔｉｍ基因扩增和序列分析方法，可探寻世界范围内贾第虫株之间的遗传学关系。

The triose phosphate isomerase (tim) gene which encodes a metabolic enzyme is present in all isolates of Glamblia.Sequencing the tim gene has been utilized by investigators to identify the genetic relationship between isolates obtained from different hosts and/or different geographic origins.For identifying the genotype of the Chinese isolates,we have sequenced the tim genes of 3 Glamblia isolates (C1,C2 and C3) isolated from different districts of China.The results demonstrated that C1 and C2 were genetically identical and could be allocated to group 3(GS) of the Barudh’s grouping system.C3 coantained two different genetic types.This indicated that the host from whom it was isolated might have been simultaneously infected with 2 different genetic types of the organism (WB and GS).Sequencing a protein coding gene could constitute a useful means for epidemiological classification of GLamblia.