title: [Phylogenetic and degrading genes analysis of a PAH-degrading bacterium TVG9-VII from deep-sea hydrythermal environment].
abstract: OBJECTIVE
  The aim of this study is to identify a polycyclic aromatic hydrocarbons (PAHs)-degrading bacterium isolated from deep-sea hydrothermal environment, including its taxonomy, characteristics and mechanism involved in PAH degradation.
  
  
  METHODS
  The phylogeny was studied by 16S rRNA gene clone, and the degradation rates against different PAHs were determined by GC-MS. Meanwhile, PAH-degrading gene cluster was cloned by the genomic Fosmid library construction; the function of the key degrading-gene expression was examined by RT-PCR and qPCR to observe gene expression in the response to different PAHs.
  
  
  RESULTS
  A PAH-degrading strain TVG9-VII was isolated from the hydrothermal chimney sample of the Lau basin in Southwest Pacific Ocean. It showed 99.7% similarities with 16S rRNA gene of Novosphingobium indicum strain H25(T). The degradation rates of this strain against phenanthrene, fluoranthene and pyrene were 95.2%, 57.3% and 69.6% in 21 days, respectively. A gene cluster, containing PAHs initial dioxygenase genes pheA1a and pheA1b, was obtained from genomic fosmid library, with the insertion size of 12.522 kb. The gene pheA1a was enhanced by 4.2 folds in mRNA expression in presence of phenanthrene, but expression enhancement was not observed in other tested PAHs including naphthalene, pyrene and fluoranthene.
  
  
  CONCLUSIONS
  Strain TVG9-VII is isolated from deep-sea hydrothermal environment in genus Novosphingobium. It can degrade many kinds of PAHs, especially the high-weight-molecular PAHs.
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, Third Institution of Oceanography State Oceanic Administration, Xiamen 361005, China. donnytio@163.com
authors.forename: Chunming
authors.initials: C
authors.lastname: Dong
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.forename: Yueting
authors.initials: Y
authors.lastname: Liao
authors.forename: Zongze
authors.initials: Z
authors.lastname: Shao
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D004777:Environment; D006358:Hot Temperature; D009792:Oceans and Seas; D010802:Phylogeny; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D012623:Seawater / Q000382:microbiology*; D014871:Water Microbiology
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons