Metabolic adaptation and oxaloacetate homeostasis in P. fluorescens exposed to aluminum toxicity.
Microbial systems are known to elaborate intricate metabolic strategies in an effort to fend the toxic impact of numerous metals. In this study, we show that the exposure of Pseudomonas fluorescens to aluminum (Al) resulted in a metabolic shift aimed at diverting oxaloacetate towards the biogenesis of an aluminophore. This metabolic alteration was characterized by uncoupling of two gluconeogenic enzymes, namely pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK). While PC displayed a sharp increase in activity and expression, PEPCK was severely diminished. Malic enzyme (ME) and NAD kinase (NADK), two enzymes involved in maintaining a reductive environment, were markedly increased in the Al-stressed cells. Hence, Al-exposed Pseudomonas fluorescens evoked a metabolic response aimed at generating oxaloacetate and promoting an intracellular reductive environment.
Lemire
Joseph
J
Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada.
Kumar
Puja
P
Mailloux
Ryan
R
Cossar
Kathyrn
K
Appanna
Vasu D
VD
D000535:Aluminum / Q000378:metabolism / Q000633:toxicity*; D001426:Bacterial Proteins / Q000378:metabolism; D002262:Carboxy-Lyases / Q000378:metabolism; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D006706:Homeostasis; D008291:Malate Dehydrogenase / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D062907:Oxaloacetic Acid / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000187:drug effects* / Q000378:metabolism*; D011766:Pyruvate Carboxylase / Q000378:metabolism; D015854:Up-Regulation
D001426:Bacterial Proteins; D062907:Oxaloacetic Acid; D000535:Aluminum; D008291:Malate Dehydrogenase; D017853:Phosphotransferases (Alcohol Group Acceptor); C021844:NAD kinase; D002262:Carboxy-Lyases; D011766:Pyruvate Carboxylase