title: Absence of membrane phosphatidylcholine does not affect virulence and stress tolerance phenotypes in the opportunistic pathogen Pseudomonas aeruginosa.
abstract: During growth in presence of choline, both laboratory and clinical Pseudomonas aeruginosa strains synthesize phosphatidylcholine (PC), and PC makes up ∼4% of the total membrane phospholipid content. In all the strains tested, PC synthesis occurred only when choline is provided exogenously. Mutants defective in synthesis of PC were generated in the strain backgrounds PAO1 and PA14. Minimum inhibitory concentration studies testing sensitivity of PC-deficient strains towards various antibiotics and cationic antimicrobial peptides revealed no differences as compared to wild-type strains. Mutants incapable of synthesizing PC were also found to be unaffected in motility and biofilm formation on abiotic surfaces, colonization of biotic surfaces and virulence in a mouse infection model. A global phenotypic microarray was further used to identify conditions wherein membrane PC may play a role of in P. aeruginosa. No culture conditions were identified wherein wild-type and PC-deficient mutants showed phenotypic differences. Membrane PC may serve a highly specific role during P. aeruginosa interactions with its eukaryotic hosts based on all the clinical strains tested retaining the ability to synthesize it during availability of choline.
authors.affiliation: Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire, United States of America.
authors.forename: Adel A
authors.initials: AA
authors.lastname: Malek
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Wargo
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Hogan
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D015169:Colony Count, Microbial; D006801:Humans; D051379:Mice; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010713:Phosphatidylcholines / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000166:cytology / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology*; D013312:Stress, Physiological / Q000187:drug effects; D013499:Surface Properties / Q000187:drug effects; D014774:Virulence / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D010713:Phosphatidylcholines