title: A novel regulator PA5022 (aefA) is involved in swimming motility, biofilm formation and elastase activity of Pseudomonas aeruginosa.
abstract: Pseudomonas aeruginosa is an opportunistic pathogen contributing to a range of nosocomial infections. To identify new genes involved in P. aeruginosa swimming motility, an important mechanism of pathogenesis, mutants with altered swimming motility patterns from Mu transposon mutagenesis library of the P. aeruginosa clinical strain PA68 were isolated and characterized. We identified a mutant with transposon inactivation of PA5022 has completely abolished its swimming motility while still possesses a normal terminal flagellum according to electronic microscopy analysis. Microscopic examination revealed that the PA5022 mutant forms thicker biofilms compared to the PA68 wild-type strain and is impaired in its elastase activity. To exclude the possibility of genetic diversity in affecting gene functions among different strains, we constructed a PA5022 knock out mutant based on the PAK lab strain. The PAKΔPA5022 has similar phenotypes to the PA5022 (PA5022::Mu) mutant of PA68 strain. Furthermore, transcriptional fusion assays were carried out to investigate the regulatory mechanism of PA5022 by using the PlasI-lacZ, PrhlI-lacZ, PrpoN-lacZ, PrpoS-lacZ, PqscR-lacZ, PvqsR-lacZ fusions. β-Galactosidase activity assays indicated that the expression of the vqsR, lasI and rhlI promotors was reduced in the PA5022 mutant compared to the PA68 wild-type. Our study showed that PA5022 links swimming motility and quorum sensing, which might be an important regulator for the pathogenesis of P. aeruginosa.
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China; School of Public Health, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Yingli
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Bai
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Huiming
authors.initials: H
authors.lastname: Xia
authors.affiliation: Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Luning
authors.initials: L
authors.lastname: Zhuang
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Haijin
authors.initials: H
authors.lastname: Xu
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Jin
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Xiuming
authors.initials: X
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Bai
authors.affiliation: College of Life Sciences, Nankai University, Tianjin 300071, China. Electronic address: nk3mlab@yahoo.com.
authors.forename: Mingqiang
authors.initials: M
authors.lastname: Qiao
mesh_terms: D010583:Bacteriophage mu; D018441:Biofilms / Q000254:growth & development*; D005407:Flagella / Q000648:ultrastructure; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008124:Locomotion; D046529:Microscopy, Electron, Transmission; D016254:Mutagenesis, Insertional; D010196:Pancreatic Elastase / Q000096:biosynthesis*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D014157:Transcription Factors; D010196:Pancreatic Elastase
keywords: Biofilm formation; Elastase activity; P. aeruginosa; PA5022 gene; Swimming motility