title: Physiology of Geobacter metallireducens under excess and limitation of electron donors. Part I. Batch cultivation with excess of carbon sources.
abstract: For microorganisms that play an important role in bioremediation, the adaptation to swift changes in the availability of various substrates is a key for survival. The iron-reducing bacterium Geobacter metallireducens was hypothesized to repress utilization of less preferred substrates in the presence of high concentrations of easily degradable compounds. In our experiments, acetate and ethanol were preferred over benzoate, but benzoate was co-consumed with toluene and butyrate. To reveal overall physiological changes caused by different single substrates and a mixture of acetate plus benzoate, a nano-liquid chromatography-tandem mass spectrometry-based proteomic approach (nano-LC-MS/MS) was performed using label-free quantification. Significant differential expression during growth on different substrates was observed for 155 out of 1477 proteins. The benzoyl-CoA pathway was found to be subjected to incomplete repression during exponential growth on acetate in the presence of benzoate and on butyrate as a single substrate. Peripheral pathways of toluene, ethanol, and butyrate degradation were highly expressed only during growth on the corresponding substrates. However, low expression of these pathways was detected in all other tested conditions. Therefore, G. metallireducens seems to lack strong carbon catabolite repression under high substrate concentrations, which might be advantageous for survival in habitats rich in fatty acids and aromatic hydrocarbons.
authors.affiliation: Institute of Groundwater Ecology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors.forename: Sviatlana
authors.initials: S
authors.lastname: Marozava
authors.affiliation: Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
authors.forename: Wilfred F M
authors.initials: WF
authors.lastname: Röling
authors.affiliation: Department Proteomics, Helmholtz Center for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Institute of Animal Nutrition, University of Hohenheim, Emil-Wolff-Str. 10, 70599 Stuttgart, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Seifert
authors.affiliation: Teaching and Research Unit Bioinformatic, Institut für Informatik, Ludwig-Maximilians-Universität München, Amalienstr. 17, 80333 Munich, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Küffner
authors.affiliation: Department Proteomics, Helmholtz Center for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Department Metabolomics, Helmholtz Center for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: von Bergen
authors.affiliation: Institute of Groundwater Ecology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany. Electronic address: rainer.meckenstock@helmholtz-muenchen.de.
authors.forename: Rainer U
authors.initials: RU
authors.lastname: Meckenstock
mesh_terms: D000085:Acetates / Q000378:metabolism; D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000032:analysis; D001565:Benzoates / Q000378:metabolism; D002244:Carbon / Q000378:metabolism*; D002853:Chromatography, Liquid; D003470:Culture Media / Q000737:chemistry*; D045302:Geobacter / Q000254:growth & development* / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D020543:Proteome / Q000032:analysis; D053719:Tandem Mass Spectrometry
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; D001565:Benzoates; D003470:Culture Media; D020543:Proteome; D002244:Carbon
keywords: Carbon catabolite repression; Geobacter metallireducens; Label-free proteomics