分离自我国蜜蜂的一株新的致病螺原体及其基本特性

A new pathogenic spiroplasma isolate obtained from honeybee in China and its basic properties

摘要:

【目的】通过分析分离自我国患病蜜蜂体内的螺原体MF1006的基本生物学特征, 初步确定其分类地位及致病性。【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, 运用常规螺原体分离和培养方法、分子生物学方法和血清学方法研究螺原体分离菌株可能的分类地位, 并采用饲喂接种法研究其致病性。【结果】菌株MF1006具有典型的螺旋形和运动性, 能通过0.22 μm孔径的滤膜, 与我国之前发现的引起蜜蜂螺原体病的参比菌株Spiroplasma melliferum CH-1的基本生物学特征差异较大。S. melliferum CH-1抗血清对其没有抑制作用。根据16S rDNA、ITS序列构建系统发育树显示, 菌株MF1006与在法国发现的引起蜜蜂“五月病”的Spiroplasma apis的亲缘关系最近。此外, 菌株MF1006对供试意蜂有较强的致病性。【结论】分离菌株MF1006是在我国蜜蜂体内发现的除S. melliferum以外的另一种致病螺原体。

Abstract:

[Objective] The purpose of this study was to characterize the isolate MF1006, and to determine the taxonomy and pathogenicity of the spiroplasma obtained from diseased hon-eybees in China. [Methods] The spiroplasma morphology was examined by dark-field micro-scope and transmission electron microscope. The biological characteristic of the spiroplasma was investigated by using conventional culture-dependent method and molecular biology and serological methods. We determined the spiroplasma pathogenicity through feeding tests. [Results] MF1006 exhibited typical properties of spiral morphology and mobility. It was able to pass through membrane filters with pores size of 220 nm. This isolate was very different from the previous reported domestic isolate Spiroplasma melliferum CH-1 which caused hon-eybee spiroplasmosis seriously. S. melliferum CH-1 antiserum could not inhibit MF1006. Phylogenetic analysis based on the 16S rDNA and ITS revealed that MF1006 was close to S. apis which was found in France and associated with a lethal infection (“May disease”) for honeybee. In addition, MF1006 expressed strong pathogenicity to A. mellifera. [Conclusion] MF1006 was the second pathogenic spiroplasma to honeybees in China.