黄道蚜蝇螺原体的分离及其基本生物学特性

Isolation and characterisation of Spiroplasma sp. from Phytomia zonata(Diptera:Syrphidae)

【目的】调查我国部分昆虫螺原体的存在情况,收集我国的昆虫螺原体资源,并研究它们的基本生物学特性,初步确定其分类地位。【方法】螺原体分离、培养方法,应用暗视野显微镜和透射电子显微镜观察螺原体形态,根据16S rDNA构建系统发育树研究螺原体分离菌株可能的分类地位。【结果】从黄道蚜蝇昆虫体内分离到螺原体YY0801,并对其进行了形态学、基本生物学及分子生物学特性研究。分离菌株在R2液体培养基中生长良好,能通过孔径为0.22μm、0.45μm的微孔滤膜;在R2固体培养基上呈颗粒状菌落;在对数期呈典型的螺旋状;能利用葡萄糖、D-果糖作为碳源;能强烈代谢精氨酸;不能利用尿素;在含氨苄青霉素钠(2000U/mL)的R2液体培养基中生长良好。根据16S rDNA构建的系统发育树显示,分离菌株YY0801与血清组Ⅰ的Spiroplasma melliferum聚类较近。【结论】首次在国内从食蚜蝇科的黄道蚜蝇中(Phytomia zonata)分离到螺原体,分离菌株YY0801可能是Spiroplasma melliferum,但其确切的分类地位需要进行血清学进一步分析。

[Objective] To obtain the spiroplasma resources and characterize the spiroplasmas from insects in China, as well as study the taxonomy of spiroplasma based on biological characteristics. [ Methods] We determined morphology by using dark field and transmission electron microscopy. The biological characteristics of the spiroplasmas were studied by using conventional culture-dependent method and phylogenetie analysis based on 16S rDNA. [ Results] Based on morphological characteristics, biological characteristics and phylogenetic evidences, we studied the taxonomy of the strain YY0801 isolated from Phytomia zonata （Diptera： Syrphidae）. The isolate grew well in R2 liquid medium and could pass through 0.22 μm and 0.45μm filtrate membranes. The colony was grain-like in solid medium. Through electron microscopy, the isolate YY0801 exhibited helicity during their exponential growth phase. The isolate YY0801 was able to ferment glucose and D-fructose and to catabolize arginine, but did not to hydrolyse urea. The isolate was resistant to ampicillin （2000 U/mL）. The phylogenetic relationships based on 16S rDNA supported YY0801 grouped with the serogroup l and was close to S. melliferum. [ Conclusion] The result indicated that the spiroplasma isolate YY0801 was close to S. melliferum, but further designation need support of serological analyses.