title: [Involvement of quorum-sensing in biosynthesis of polyhydroxyalkanoates in Pseudomonas aeruginosa].
abstract: Quorum-sensing (QS) is a regulatory mechanism with which bacteria regulate the gene expression according to their population density. Pseudomonas aeruginosa regulates the expression of multiple genes via a hierarchical quorum-sensing cascade through LasR and RhlR and their cognate signal molecules N-(3-oxododecanoyl)-L-homoserine lactone (30-C12-HSL) and N-(butanoyl)-L-homoserine lactone (C4-HSL).
  
  
  OBJECTIVE
  It aims to explore the regulation of QS on biosynthesis of polyhydroxyalkanoates (PHA) in P. aeruginosa.
  
  
  METHODS
  Wild-type P. aeruginosa PA01 and its QS mutants were used to investigate the effects of quorum-sensing on biosynthesis of PHA by GC and real-time PCR at physiological and molecular level.
  
  
  RESULTS
  After treated with QS signal molecule synthesis inhibitor azithromycin, the accumulation of PHA significantly decreased in P. aeruginosa PA01 and its QS mutant strains. The content of PHA in C4-HSL synthase gene rhlI mutant strain PA0210 had no significant difference compared with that of the wild type. However, the PHA contents were significantly affected in 30C12-HSL synthase gene lasl mutant strain PA055, 30C12-HSL transcriptional regulator gene lasR mutant strain PA056 and lasI/lasR double mutant strain PA057. PHA synthase gene phaC1 expression exhibited a significant reduction in lasI mutant and lasR mutant strains. 30C12-HSL signal molecules complementary experiment shows that the expression of phaC1 can be recovered to the level of the wild type, but the synthesis of PHA is only partially restored in lasI mutant strain.
  
  
  CONCLUSIONS
  The results implicates that lasI/lasR system might be involved in the regulation of intracellular PHA biosynthesis in P. aeruginosa PA01.
authors.affiliation: Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051, China. 2004xucao@163.com
authors.forename: Cao
authors.initials: C
authors.lastname: Xu
authors.forename: Man
authors.initials: M
authors.lastname: Li
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Huang
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.forename: Zirui
authors.initials: Z
authors.lastname: Bian
authors.forename: Shuishan
authors.initials: S
authors.lastname: Song
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology*; D053038:Quorum Sensing
chemical_list: D001426:Bacterial Proteins; D054813:Polyhydroxyalkanoates; C088386:homoserine lactone; D015107:4-Butyrolactone