日本立克次体DNA扩增产物的序列分析及其应用于蜱媒的鉴定

Sequence Analysis of the Amplified Product from Rickettsia japonica DNA and Its Application for the Identification of Tick Vectors

序列分析由日本立克次体ＤＮＡ扩增的５８９－ｂＰＣＲ产物。该扩增引物来自立氏立克次体的１９０ｋＤ蛋白的基因序列。ＰＣＲ产物含有－５３３ｂＰＤＮＡ片段，该片段可被Ｒｒｌ９０．７０ｐ和Ｒｒ１９０．６０２ｎ引物所扩增［６］。日本立克次体的这个ＤＮＡ片段的序列与立氏立克次体进行比较，发现这两种立克次体该部分ＤＮＡ的遗传同源性为９３％。序列分析确定４种内切酶用于ＰＣＲ－ＲＦＬＰ鉴别日本立克次体，用这种技术，长角血蜱被鉴定为东方斑点热病的蜱媒。

A PCR product with a molecular size of 589 base pairs(bp)amplified from Rickettsia japonica DNA by using the primers which were devised from R. rickettsii 190 kD protein gene sequence was sequenced.In the PCR product,a 533-bp DNA fragment which can be amplified by the primers Rr 190.70p and Rr 190.602n[6] was contained.Comparison of the partial sequence of R. japonica with that of R,rickettsii revealed that a high degree of genetic homology(93%)was between the two species. Four restriction enzymes that were fit for the PCR-RFLP in differentiation of R,japonica from other spotted fever group rickettsiae were selected from the sequence. By the PCR-RFLP,a tick,Haemaphysalis longicornis,was identified as the vector of Oriental spotted fever caused by R. japonica.