title: Influence of the Crc regulator on the hierarchical use of carbon sources from a complete medium in Pseudomonas.
abstract: The Crc protein, together with the Hfq protein, participates in catabolite repression in pseudomonads, helping to coordinate metabolism. Little is known about how Crc affects the hierarchy of metabolite assimilation from complex mixtures. Using proton Nuclear Magnetic Resonance (NMR) spectroscopy, we carried out comprehensive metabolite profiling of culture supernatants (metabolic footprinting) over the course of growth of both Pseudomonas putida and P. aeruginosa, and compared the wild-type strains with deletion mutants for crc. A complex metabolite consumption hierarchy was observed, which was broadly similar between the two species, although with some important differences, for example in sugar utilization. The order of metabolite utilization changed upon inactivation of the crc gene, but even in the Crc-null strains some compounds were completely consumed before late metabolites were taken up. This suggests the presence of additional regulatory elements that determine the time and order of consumption of compounds. Unexpectedly, the loss of Crc led both species to excrete acetate and pyruvate as a result of unbalanced growth during exponential phase, compounds that were later consumed in stationary phase. This loss of carbon during growth helps to explain the contribution of the Crc/Hfq regulatory system to evolutionary fitness of pseudomonads.
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049, Madrid, Spain.
authors.forename: Ruggero
authors.identifier: http://orcid.org/0000-0002-6705-3989
authors.initials: R
authors.lastname: La Rosa
authors.affiliation: Department of Life Sciences, University of Roehampton, London, SW15 4DJ, UK.|Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Volker
authors.identifier: http://orcid.org/0000-0003-4855-5497
authors.initials: V
authors.lastname: Behrends
authors.affiliation: Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Huw D
authors.initials: HD
authors.lastname: Williams
authors.affiliation: Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Jacob G
authors.initials: JG
authors.lastname: Bundy
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049, Madrid, Spain.
authors.forename: Fernando
authors.identifier: http://orcid.org/0000-0003-1848-7745
authors.initials: F
authors.lastname: Rojo
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D057465:Catabolite Repression / Q000235:genetics; D003470:Culture Media; D035001:Host Factor 1 Protein / Q000378:metabolism; D011549:Pseudomonas / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism*; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D035001:Host Factor 1 Protein; D012097:Repressor Proteins; C101896:crc protein, Pseudomonas; D002244:Carbon