Sharma Ashwani, Thakur Indu Shekhar
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India.
J Environ Sci (China). 2009;21(6):858-64. doi: 10.1016/s1001-0742(08)62353-0.
A bacterial consortium was developed by continuous enrichment of microbial population isolated from sediment core of pulp and paper mill effluent in mineral salts medium (MSM) supplemented with pentachlorophenol (PCP) as sole source of carbon and energy in the chemostat. The consortia contained three bacterial strains. They were identified as Escherichia coli, Pseudomonas aeruginosa and Acinetobacter sp. by 16S rRNA gene sequence analysis. Acinetobacter sp. readily degraded PCP through the formation of tetrachloro-p-hydroquinone (TecH), 2-chloro-1,4-benzenediol and products of ortho ring cleavage detected by gas chromatograph/mass spectrometer (GC-MS). Out of the three acclimated PCP degrading bacterial strains only one strain, Acinetobacter sp. showed the presence of integron gene cassette as a marker of its stability and antibiotic resistance. The strain possessed a 4.17 kb amplicon with 22 ORF's. The plasmid isolated from the Acinetobacter sp. was subjected to shotgun cloning through restriction digestion by BamHI, HindIII and SalI, ligated to pUC19 vector and transformed into E. coli XLBlue1alpha, and finally selected on MSM containing PCP as sole source of carbon and energy with ampicillin as antibiotic marker. DNA sequence analysis of recombinant clones indicated homology with integron gene cassette and multiple antibiotic resistance genes.
通过在恒化器中以五氯苯酚（PCP）作为唯一碳源和能源补充的矿物盐培养基（MSM）中连续富集从造纸厂废水沉积物核心分离的微生物群体，构建了一个细菌联合体。该联合体包含三种细菌菌株。通过16S rRNA基因序列分析，它们被鉴定为大肠杆菌、铜绿假单胞菌和不动杆菌属。不动杆菌属通过形成四氯对苯二酚（TecH）、2-氯-1,4-苯二酚以及通过气相色谱/质谱仪（GC-MS）检测到的邻位环裂解产物，很容易地降解PCP。在三种适应PCP降解的细菌菌株中，只有一种菌株，即不动杆菌属，显示出整合子基因盒的存在，作为其稳定性和抗生素抗性的标志。该菌株拥有一个4.17 kb的扩增子，带有22个开放阅读框（ORF）。从不动杆菌属分离的质粒通过用BamHI、HindIII和SalI进行限制性消化进行鸟枪法克隆，连接到pUC19载体上，并转化到大肠杆菌XLBlue1α中，最后在以PCP作为唯一碳源和能源且以氨苄青霉素作为抗生素标记的MSM上进行筛选。重组克隆的DNA序列分析表明与整合子基因盒和多种抗生素抗性基因具有同源性。
