title: [Positive regulation in expression of the phenazine-producing operon phz2 mediated by pip in Pseudomonas aeruginosa PAO1].
abstract: Pseudomonas aeruginosa PAO1, an opportunistic pathogenic bacterium, produces phenazine and its derivatives which play a critical role in pathogen-host interaction during its infection. In a biological control strain P. chlororaphis PCL1391, Pip positively regulates PCN production.
  
  
  OBJECTIVE
  Our aim is to identify the function and regulation of an ORF of PA0243 (the homolog of Pip) in Pseudomonas aeruginosa PAO1.
  
  
  METHODS
  We first cloned the fragment of the pip gene from the chromosomal DNA of P. aeruginosa PAO1 and constructed the pip-defect mutant PA-PG with the insertion of gentamycin resistance cassette (aacC1). With construction and introduction of pME10P (containing the whole pip gene region) , complementation of the pip was then carried out. With creation of the mutants PA-PD-Z1G and PA-PG-Z2K, phenazine-1-carboxylic acid and pyocyanin were measured in GA medium in relative mutants, respectively.
  
  
  RESULTS
  In GA medium, production of phenazine-1-carboxylic acid and pyocyanin in the mutant PA-PG decreased dramatically in comparison with that produced in the wild type strain PAO1. The amounts of phenazine-1-carboxylic acid and pyocyanin, however, were recovered with complementation of the derivative PA-PG bearing pME10P. The production of phenazine-1-carboxylic acid and pyocyanin in mutant PA-PG-Z2K were same to those in parental strain PA-Z2K. Phenazine-1-carboxylic acid and pyocyanin produced by the mutant PA-PD-Z1G were lower than those in the original strain PA-Z1G.
  
  
  CONCLUSIONS
  With these results, it is suggested that Pip exerts positively regulation in phenazine biosynthesis by specifically modulating expression of the phz2 operon, not by mediating expression of the phzl operon in P. aeruginosa PAO1.
authors.affiliation: School of Life Sciences, Ludong University, Yantai 264025, China. zhyuan0824@sina.cn
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qinna
authors.initials: Q
authors.lastname: Cui
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhao
authors.forename: Yongfei
authors.initials: Y
authors.lastname: Ming
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Chi
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Feng
authors.forename: Shiwei
authors.initials: S
authors.lastname: Cheng
authors.forename: Weihai
authors.initials: W
authors.lastname: Xie
authors.forename: Yihe
authors.initials: Y
authors.lastname: Ge
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D009876:Operon; D010619:Phenazines / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism*; D011710:Pyocyanine / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; D010619:Phenazines; D014157:Transcription Factors; C037165:1-phenazinecarboxylic acid; D011710:Pyocyanine