title: Long-term anaerobic survival of the opportunistic pathogen Pseudomonas aeruginosa via pyruvate fermentation.
abstract: Denitrification and arginine fermentation are central metabolic processes performed by the opportunistic pathogen Pseudomonas aeruginosa during biofilm formation and infection of lungs of patients with cystic fibrosis. Genome-wide searches for additional components of the anaerobic metabolism identified potential genes for pyruvate-metabolizing NADH-dependent lactate dehydrogenase (ldhA), phosphotransacetylase (pta), and acetate kinase (ackA). While pyruvate fermentation alone does not sustain significant anaerobic growth of P. aeruginosa, it provides the bacterium with the metabolic capacity for long-term survival of up to 18 days. Detected conversion of pyruvate to lactate and acetate is dependent on the presence of intact ldhA and ackA-pta loci, respectively. DNA microarray studies in combination with reporter gene fusion analysis and enzyme activity measurements demonstrated the anr- and ihfA-dependent anaerobic induction of the ackA-pta promoter. Potential Anr and integration host factor binding sites were localized. Pyruvate-dependent anaerobic long-term survival was found to be significantly reduced in anr and ihfA mutants. No obvious ldhA regulation by oxygen tension was observed. Pyruvate fermentation is pH dependent. Nitrate respiration abolished pyruvate fermentation, while arginine fermentation occurs independently of pyruvate utilization.
authors.affiliation: Institute of Microbiology, Technical University Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Eschbach
authors.forename: Kerstin
authors.initials: K
authors.lastname: Schreiber
authors.forename: Katharina
authors.initials: K
authors.lastname: Trunk
authors.forename: Jan
authors.initials: J
authors.lastname: Buer
authors.forename: Dieter
authors.initials: D
authors.lastname: Jahn
authors.forename: Max
authors.initials: M
authors.lastname: Schobert
mesh_terms: D000084:Acetate Kinase / Q000235:genetics / Q000378:metabolism; D000085:Acetates / Q000378:metabolism; D000693:Anaerobiosis; D001120:Arginine / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D017930:Genes, Reporter; D006863:Hydrogen-Ion Concentration; D034982:Integration Host Factors / Q000235:genetics / Q000502:physiology; D007770:L-Lactate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D009154:Mutation; D009566:Nitrates / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010709:Phosphate Acetyltransferase / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D034982:Integration Host Factors; D009566:Nitrates; D015534:Trans-Activators; C072908:ANR protein, Pseudomonas aeruginosa; D019344:Lactic Acid; D019289:Pyruvic Acid; D001120:Arginine; D007770:L-Lactate Dehydrogenase; D010709:Phosphate Acetyltransferase; D000084:Acetate Kinase; D001616:beta-Galactosidase