title: Involvement of fumarase C and NADH oxidase in metabolic adaptation of Pseudomonas fluorescens cells evoked by aluminum and gallium toxicity.
abstract: Iron (Fe) is a critical element in all aerobic organisms as it participates in a variety of metabolic networks. In this study, aluminum (Al) and gallium (Ga), two Fe mimetics, severely impeded the ability of the soil microbe Pseudomonas fluorescens to perform oxidative phosphorylation. This was achieved by disrupting the activity and expression of complexes I, II, and IV. These toxic metals also inactivated aconitase (ACN) and fumarase A (FUM A), two tricarboxylic acid cycle enzymes dependent on Fe for their catalytic activity, while FUM C, an Fe-independent enzyme, displayed an increase in activity and expression under these stressed situations. Furthermore, in the Al- and Ga-exposed cells, the activity and expression of an H(2)O-forming NADH oxidase were markedly increased. The incubation of the Al- and Ga-challenged cells in an Fe-containing medium led to the recovery of the affected enzymatic activities. Taken together, these data provide novel insights into how environmental pollutants such as Al and Ga interfere with cellular Fe metabolism and also illustrate the ability of Pseudomonas fluorescens to modulate metabolic networks to combat this situation.
authors.affiliation: Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6.
authors.forename: Daniel
authors.initials: D
authors.lastname: Chenier
authors.forename: Robin
authors.initials: R
authors.lastname: Beriault
authors.forename: Ryan
authors.initials: R
authors.lastname: Mailloux
authors.forename: Mathurin
authors.initials: M
authors.lastname: Baquie
authors.forename: Gia
authors.initials: G
authors.lastname: Abramia
authors.forename: Joseph
authors.initials: J
authors.lastname: Lemire
authors.forename: Vasu
authors.initials: V
authors.lastname: Appanna
mesh_terms: D000222:Adaptation, Physiological; D000535:Aluminum / Q000633:toxicity*; D003470:Culture Media; D004785:Environmental Pollutants / Q000633:toxicity; D005649:Fumarate Hydratase / Q000235:genetics / Q000378:metabolism*; D005708:Gallium / Q000633:toxicity*; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000502:physiology
chemical_list: D003470:Culture Media; D004785:Environmental Pollutants; D009097:Multienzyme Complexes; D005708:Gallium; D000535:Aluminum; D007501:Iron; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; C095842:fumarase C; D005649:Fumarate Hydratase