一株多环芳烃降解菌的鉴定及GST基因克隆和序列分析

Identification,Cloning and Sequencing of GST Gene of Bacterium Degrading Poly-aromatic Hydrocarbons

由石油污染土壤中分离到一株能以多环芳烃 (菲、芴、萘 )为唯一碳源的细菌 ,经形态观察、生理生化 (Biolog GN)和G +Cmol%分析 ,鉴定该菌为少动鞘氨醇单胞菌 (Sphingomonaspaucimobilis)。与 1 6SrDNA序列同源性的比较进一步确证了鉴定结果。经菲诱导后的细菌谷胱甘肽S 转移酶 (GlutathioneS transferase ,GST)酶活明显高于未诱导前 ,表明谷胱甘肽S 转移酶可能与多环芳烃的降解有关。根据该酶基因的同源性序列设计引物 ,PCR扩增出编码谷胱甘肽S 转移酶基因片段 ,进一步证实在该菌中有GST的存在。测序后基于编码GST的基因所进行的系统发育分析表明 ,该多环芳烃降解菌与其它多环芳烃降解菌在进化上亲缘关系较近。

A bacterium (designated strain ZX4) able to degrade poly aromatic hydrocarbons was isolated from oil-contaminated soil. Based on analysis of the 16S rDNA sequence, whole cell fatty acid, and Biolog-GN, the strain was identified as Sphingomonas paucimobilis. The detection of GST (Glutathione S-transferase) indicated that the GST from the strain had the activity of conjugating with CDNB and it maybe relate with degradation of PAHs. The PCR product of GST gene from the strain confirmed its presence. Phylogeny analysis based on gst sequence indicated that the strain was relatively close with the strain which can degrade PAH likewise.