Quan Xiang-Chun, Tang Hua, Hu Li-Juan, Wang Ran, Zhang Ning
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
Huan Jing Ke Xue. 2009 Sep 15;30(9):2728-34.
With plasmid pJP4 (which contains functional gene cluster (tfd) encoding 2,4-D degradation) carrying genetic microorganism Pseudomonas putida SM1443:: gfp2x (pJP4:: dsRed) as the donor strain, events of plasmid mediated gene horizontal transfer and its effect on 2,4-D degradation was investigated in a biofilm system operated under fed-batch mode. The surviving status of the functional gene element in the gene-augmented system and effects of gene-augmentation on microbial community structure were also investigated. Results showed that introduction of pJP4 carrying strain to the biofilm system with 2, 4-D (initial concentration at 170 mg/L +/- 10 mg/L) as the sole carbon source could enhance the degradation of 2, 4-D. Enhancement was slight during the initial stage of operation, but it increased with increasing of fed batch runs. Difference in 2, 4-D average degradation rate between gene-augmented system and the control system achieved up to 13.3 mg/(L x h) at most. Through detecting functional gene tfdB and reporter gene gfp, pJP4 mediated gene horizontal transfer to the bacteria on biofilm was further approved. Effects of gene augmentation on microbial community structure was analyzed by PCR-DGGE analysis, and results showed that relatively higher stability of microbial community was maintained for the gene-augmented biofilm system compared to the control system when facing 2,4-D shock loadings.
以携带编码2,4 - D降解功能基因簇（tfd）的质粒pJP4的遗传微生物恶臭假单胞菌SM1443::gfp2x（pJP4::dsRed）作为供体菌株，在分批补料模式运行的生物膜系统中研究了质粒介导的基因水平转移事件及其对2,4 - D降解的影响。还研究了功能基因元件在基因强化系统中的存活状态以及基因强化对微生物群落结构的影响。结果表明，将携带pJP4的菌株引入以2,4 - D（初始浓度为170 mg/L±10 mg/L）作为唯一碳源的生物膜系统中，可以增强2,4 - D的降解。在运行初期增强作用较小，但随着分批补料运行次数的增加而增加。基因强化系统与对照系统之间的2,4 - D平均降解速率差异最大达到13.3 mg/(L·h)。通过检测功能基因tfdB和报告基因gfp，进一步证实了pJP4介导的基因水平转移至生物膜上的细菌。通过PCR - DGGE分析对基因强化对微生物群落结构的影响进行了分析，结果表明，与对照系统相比，基因强化生物膜系统在面对2,4 - D冲击负荷时保持了相对较高的微生物群落稳定性。
