蛭弧菌类菌株JU-PX1的生物学特性和16S rDNA序列分析

The predation characteristics and 16S rDNA sequence analysis of Bdellovibrio-and-like organism strain JU-PX1

摘要:

【目的】研究蛭弧菌类菌株JU-PX1的噬菌特性、形态特征, 并分析16S rDNA序列从而对其进行种属鉴定。【方法】采用双层平板法和三角瓶培养法研究蛭弧菌类菌株JU-PX1的噬菌特性, 通过光镜和电镜观察其形态, 利用16S rDNA序列的蛭弧菌类特异性引物以及细菌通用引物进行PCR扩增。【结果】JU-PX1对10株宿主菌中的6株具有噬菌作用, 特别对大肠杆菌和副溶血弧菌侵噬能力较强。菌体呈弧状或杆状, 单极鞭毛, 大小为(0.2?0.5) μm×(0.8?1.2) μm, 在其增殖阶段也有长约3.2 μm的较长个体。扩增后分别获得了一段长为831 bp和1 515 bp的DNA序列, 进一步通过NCBI BLAST和MEGA?5.10等软件分析并构建了系统发育树。【结论】蛭弧菌类菌株JU-PX1属于噬菌弧菌属(Bacteriovorax), 与海岸噬菌弧菌(Bv. litoralis)亲缘关系最近, 两者的16S rDNA序列相似性为93%。

Abstract:

[Objective] The predation ability, morphological characteristics and 16S rDNA characteristics of Bdellovibrio-and-like organism (BALO) strain JU-PX1 will be studied. [Methods] The predation ability of JU-PX1 have been studied by double-layer agar and conical flask culture. The morphological characteristics of JU-PX1 were examined with optical microscope and transmission electron microscope. Using BALOs-specific primer and universal primer, 16S rDNA fragment of JU-PX1 were obtained by PCR amplification. [Results] Seven of the ten strains tested, especially Escherichia coli and Vibrio parahaemolyticus, could be hunted by JU-PX1. JU-PX1 exhibited typical BALOs pattern, showing vibrioid cell with a single polar flagellum. The cell size was (0.2?0.5) μm×(0.8?1.2) μm, and there was also 3.2?μm elongating cell in exponential phase. Two kinds of 16S rDNA fragment of JU-PX1 were obtained by PCR amplification, which lengths were 831 bp and 1 515 bp, respectively. The 16S rDNA was analysed on phylogenetic tree by NCBI BLAST and MEGA 5.10. [Conclusion] BALO JU-PX1 had the closest relationship with Bacteriovorax litoralis and the similarity was 93%.