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Although aluminum is known to be toxic to most organisms, its precise biochemical interactions are not fully understood. In the present study, we demonstrate that aluminum promotes the inhibition of aconitase (Acn) activity via the perturbation of the Fe-S cluster in Pseudomonas fluorescens. Despite the significant decrease in citrate isomerization(More)
The tricarboxylic acid (TCA) cycle is an essential metabolic network in all oxidative organisms and provides precursors for anabolic processes and reducing factors (NADH and FADH(2)) that drive the generation of energy. Here, we show that this metabolic network is also an integral part of the oxidative defence machinery in living organisms and(More)
Aluminum (Al), a known environmental toxicant, has been linked to a variety of pathological conditions such as dialysis dementia, osteomalacia, Alzheimer's disease, and Parkinson's disease. However, its precise role in the pathogenesis of these disorders is not fully understood. Using hepatocytes as a model system, we have probed the impact of this(More)
Gallium (Ga), an iron (Fe) mimetic promoted an oxidative environment and elicited an antioxidative response in Pseudomonas fluorescens. Ga-stressed P. fluorescens was characterized by higher amounts of oxidized lipids and proteins compared to control cells. The oxidative environment provoked by Ga was nullified by increased synthesis of NADPH. The activity(More)
Oxalic acid plays a pivotal role in the adaptation of the soil microbe Pseudomonas fluorescens to aluminum (Al) stress. Its production via the oxidation of glyoxylate necessitates a major reconfiguration of the enzymatic reactions involved in the tricarboxylic acid (TCA) cycle. The demand for glyoxylate, the precursor of oxalic acid appears to enhance the(More)
13C NMR studies with aluminum (Al)-stressed Pseudomonas fluorescens revealed that the trivalent metal was secreted in association with oxalate and phosphatidylethanolamine (PE). These moieties were observed in the insoluble pellet obtained upon incubation of these resting cells in the presence of either Al-citrate or citrate. This extrusion process was(More)
We demonstrate a facile blue native polyacrylamide gel electrophoresis (BN-PAGE) technique to detect two malate-generating enzymes, namely fumarase (FUM), malate synthase (MS) and four oxaloacetate-forming enzymes, namely pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase (PEPCK), citrate lyase (CL) and aspartate aminotransferase (AST). Malate(More)
Aluminum (Al) triggered a marked increase in reactive oxygen species (ROS) such as O(2) (-) and H(2)O(2) in Pseudomonas fluorescens. Although the Al-stressed cells were characterized with higher amounts of oxidized lipids and proteins than controls, NADPH production was markedly increased in these cells. Blue native polyacrylamide gel electrophoresis(More)
Isocitrate lyase, ICL (EC 4.1.3.1), an enzyme that cleaves isocitrate into succinate, and glyoxylate appears to play a pivotal role in the detoxification of aluminum (Al) in Pseudomonas fluorescens. Here, we present evidence that the 4-fold increase in ICL activity observed in Al-stressed cells is due to the overexpression of this enzyme. Blue-Native-PAGE,(More)
Although the tricarboxylic acid (TCA) cycle is essential in almost all aerobic organisms, its precise modulation and integration in global cellular metabolism is not fully understood. Here, we report on an alternative TCA cycle uniquely aimed at generating ATP and oxalate, two metabolites critical for the survival of Pseudomonas fluorescens. The(More)