title: Differences in metabolism between the biofilm and planktonic response to metal stress.
abstract: Bacterial biofilms are known to withstand the effects of toxic metals better than planktonic cultures of the same species. This phenomenon has been attributed to many features of the sessile lifestyle not present in free-swimming populations, but the contribution of intracellular metabolism has not been previously examined. Here, we use a combined GC-MS and (1)H NMR metabolomic approach to quantify whole-cell metabolism in biofilm and planktonic cultures of the multimetal resistant bacterium Pseudomonas fluorescens exposed to copper ions. Metabolic changes in response to metal exposure were found to be significantly different in biofilms compared to planktonic cultures. Planktonic metabolism indicated an oxidative stress response that was characterized by changes to the TCA cycle, glycolysis, pyruvate and nicotinate and niacotinamide metabolism. Similar metabolic changes were not observed in biofilms, which were instead dominated by shifts in exopolysaccharide related metabolism suggesting that metal stress in biofilms induces a protective response rather than the reactive changes observed for the planktonic cells. From these results, we conclude that differential metabolic shifts play a role in biofilm-specific multimetal resistance and tolerance. An altered metabolic response to metal toxicity represents a novel addition to a growing list of biofilm-specific mechanisms to resist environmental stress.
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Booth
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Workentine
authors.forename: Jing
authors.initials: J
authors.lastname: Wen
authors.forename: Rustem
authors.initials: R
authors.lastname: Shaykhutdinov
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Vogel
authors.forename: Howard
authors.initials: H
authors.lastname: Ceri
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Turner
authors.forename: Aalim M
authors.initials: AM
authors.lastname: Weljie
mesh_terms: D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D002849:Chromatography, Gas; D003300:Copper / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D054750:Ecotoxicology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D053858:Metabolic Networks and Pathways; D055442:Metabolome / Q000187:drug effects / Q000502:physiology; D055432:Metabolomics / Q000379:methods*; D010933:Plankton / Q000187:drug effects / Q000378:metabolism*; D025341:Principal Component Analysis; D011551:Pseudomonas fluorescens / Q000187:drug effects / Q000378:metabolism
chemical_list: D003300:Copper