scholarly journals Involvement of Fumarase C and NADH Oxidase in Metabolic Adaptation of Pseudomonas fluorescens Cells Evoked by Aluminum and Gallium Toxicity

2008 ◽  
Vol 74 (13) ◽  
pp. 3977-3984 ◽  
Author(s):  
Daniel Chenier ◽  
Robin Beriault ◽  
Ryan Mailloux ◽  
Mathurin Baquie ◽  
Gia Abramia ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Metabolic Networks ◽  
Nadh Oxidase ◽  
Tricarboxylic Acid Cycle ◽  
Environmental Pollutants ◽  
Tricarboxylic Acid ◽  
Metabolic Adaptation ◽  
Critical Element ◽  
Acid Cycle ◽  
Fumarase C

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 H2O-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.

scholarly journals Oxidative Stress Evokes a Metabolic Adaptation That Favors Increased NADPH Synthesis and Decreased NADH Production in Pseudomonas fluorescens

2007 ◽  
Vol 189 (18) ◽  
pp. 6665-6675 ◽  
Author(s):  
Ranji Singh ◽  
Ryan J. Mailloux ◽  
Simone Puiseux-Dao ◽  
Vasu D. Appanna
Keyword(s):  
Oxidative Stress ◽  
Metabolic Pathways ◽  
Metabolic Networks ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Metabolic Adaptation ◽  
Atp Production ◽  
Oxidative Challenge ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Oxidative Insult

ABSTRACT The fate of all aerobic organisms is dependent on the varying intracellular concentrations of NADH and NADPH. The former is the primary ingredient that fuels ATP production via oxidative phosphorylation, while the latter helps maintain the reductive environment necessary for this process and other cellular activities. In this study we demonstrate a metabolic network promoting NADPH production and limiting NADH synthesis as a consequence of an oxidative insult. The activity and expression of glucose-6-phosphate dehydrogenase, malic enzyme, and NADP+-isocitrate dehydrogenase, the main generators of NADPH, were markedly increased during oxidative challenge. On the other hand, numerous tricarboxylic acid cycle enzymes that supply the bulk of intracellular NADH were significantly downregulated. These metabolic pathways were further modulated by NAD+ kinase (NADK) and NADP+ phosphatase (NADPase), enzymes known to regulate the levels of NAD+ and NADP+. While in menadione-challenged cells, the former enzyme was upregulated, the phosphatase activity was markedly increased in control cells. Thus, NADK and NADPase play a pivotal role in controlling the cross talk between metabolic networks that produce NADH and NADPH and are integral components of the mechanism involved in fending off oxidative stress.

scholarly journals An ATP and Oxalate Generating Variant Tricarboxylic Acid Cycle Counters Aluminum Toxicity in Pseudomonas fluorescens

PLoS ONE ◽  
2009 ◽  
Vol 4 (10) ◽  
pp. e7344 ◽  
Author(s):  
Ranji Singh ◽  
Joseph Lemire ◽  
Ryan J. Mailloux ◽  
Daniel Chénier ◽  
Robert Hamel ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Aluminum Toxicity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle

THE TRICARBOXYLIC ACID CYCLE, THE GLYOXYLATE CYCLE, AND THE ENZYMES OF GLUCOSE OXIDATION IN PSEUDOMONAS AERUGINOSA

1966 ◽  
Vol 12 (5) ◽  
pp. 1015-1022 ◽  
Author(s):  
Margaret von Tigerstrom ◽  
J. J. R. Campbell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glucose Oxidation ◽  
Nadh Oxidase ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Succinic Dehydrogenase ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
The Glyoxylate Cycle

The enzymes of the glyoxylate cycle, the tricarboxylic acid cycle, glucose oxidation, and hydrogen transport were measured in extracts of Pseudomonas aeruginosa grown with glucose, α-ketoglutarate, or acetate as sole carbon source. The specific activity of isocitritase was increased 25-fold by growth on acetate whereas malate synthetase was increased only 4-fold. All of the enzymes of glucose metabolism, operative at the hexose level, were inducible. The enzymes of the tricarboxylic acid cycle were present under all conditions of growth but extracts from acetate-grown cells contained only one-quarter of the fumarase and pyruvic oxidase activity and half the malate-oxidizing activity of the other extracts. Transhydrogenase, NADH oxidase, and NADPH oxidase activities were similar in each type of extracts. Most of the enzymes were present in the soluble cytoplasm, exceptions being glucose oxidase, succinic dehydrogenase, and NADH oxidase.

scholarly journals Neisseria meningitidis Uses Sibling Small Regulatory RNAs To Switch from Cataplerotic to Anaplerotic Metabolism

mBio ◽  
2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Yvonne Pannekoek ◽  
Robert A. G. Huis in ‘t Veld ◽  
Kim Schipper ◽  
Sandra Bovenkerk ◽  
Gertjan Kramer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Neisseria Meningitidis ◽  
Tricarboxylic Acid Cycle ◽  
Regulation Of Gene Expression ◽  
Stringent Response ◽  
Tricarboxylic Acid ◽  
Metabolic Adaptation ◽  
Acid Cycle ◽  
Small Regulatory Rnas ◽  
Regulatory Rnas

ABSTRACT Neisseria meningitidis (the meningococcus) is primarily a commensal of the human oropharynx that sporadically causes septicemia and meningitis. Meningococci adapt to diverse local host conditions differing in nutrient supply, like the nasopharynx, blood, and cerebrospinal fluid, by changing metabolism and protein repertoire. However, regulatory transcription factors and two-component systems in meningococci involved in adaptation to local nutrient variations are limited. We identified novel sibling small regulatory RNAs ( Neisseria metabolic switch regulators [NmsRs]) regulating switches between cataplerotic and anaplerotic metabolism in this pathogen. Overexpression of NmsRs was tolerated in blood but not in cerebrospinal fluid. Expression of six tricarboxylic acid cycle enzymes was downregulated by direct action of NmsRs. Expression of the NmsRs themselves was under the control of the stringent response through the action of RelA. Small sibling regulatory RNAs of meningococci, controlling general metabolic switches, add an exciting twist to their versatile repertoire in bacterial pathogens. IMPORTANCE Regulatory small RNAs (sRNAs) of pathogens are coming to be recognized as highly important components of riboregulatory networks, involved in the control of essential cellular processes. They play a prominent role in adaptation to physiological changes as represented by different host environments. They can function as posttranscriptional regulators of gene expression to orchestrate metabolic adaptation to nutrient stresses. Here, we identified highly conserved sibling sRNAs in Neisseria meningitidis which are functionally involved in the regulation of gene expression of components of the tricarboxylic acid cycle. These novel sibling sRNAs that function by antisense mechanisms extend the so-called stringent response which connects metabolic status to colonization and possibly virulence as well as pathogenesis in meningococci. IMPORTANCE Regulatory small RNAs (sRNAs) of pathogens are coming to be recognized as highly important components of riboregulatory networks, involved in the control of essential cellular processes. They play a prominent role in adaptation to physiological changes as represented by different host environments. They can function as posttranscriptional regulators of gene expression to orchestrate metabolic adaptation to nutrient stresses. Here, we identified highly conserved sibling sRNAs in Neisseria meningitidis which are functionally involved in the regulation of gene expression of components of the tricarboxylic acid cycle. These novel sibling sRNAs that function by antisense mechanisms extend the so-called stringent response which connects metabolic status to colonization and possibly virulence as well as pathogenesis in meningococci.

Circulating tricarboxylic acid cycle metabolite levels in citrin-deficient children with metabolic adaptation, with and without sodium pyruvate treatment

2017 ◽  
Vol 120 (3) ◽  
pp. 207-212 ◽  
Author(s):  
Hironori Nagasaka ◽  
Haruki Komatsu ◽  
Ayano Inui ◽  
Mariko Nakacho ◽  
Ichiro Morioka ◽  
...  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Metabolic Adaptation ◽  
Sodium Pyruvate ◽  
Acid Cycle

Metabolic adaptation of Pseudomonas pseudoalcaligenes CECT5344 to cyanide: role of malate–quinone oxidoreductases, aconitase and fumarase isoenzymes

2011 ◽  
Vol 39 (6) ◽  
pp. 1849-1853 ◽  
Author(s):  
M. Isabel Igeño ◽  
Gracia Becerra ◽  
M. Isabel Guijo ◽  
Faustino Merchán ◽  
Rafael Blasco
Keyword(s):  
Toxic Effect ◽  
Biological System ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Metabolic Adaptation ◽  
Pseudomonas Pseudoalcaligenes ◽  
Acid Cycle ◽  
Toxic Compound ◽  
Cyanide Resistance

In general, the biodegradation of a toxic compound by a micro-organism requires the concurrence of, at least, two features in the biological system: first, the capability of the micro-organism to metabolize the toxic compound, and secondly, the capacity to resist its toxic effect. Pseudomonas pseudoalcaligenes CECT5344 is a bacterium used in the biodegradation of cyanide because it is capable to use it as a nitrogen source. The present review is mainly focused on the putative role of iron-containing enzymes of the tricarboxylic acid cycle in cyanide resistance by P. pseudoalcaligenes CECT5344.

CO2 fixation and metabolic control in Pseudomonas saccharophila

1973 ◽  
Vol 19 (10) ◽  
pp. 1243-1250
Author(s):  
A. L. Donawa ◽  
M. Ishaque ◽  
M. I. H. Aleem
Keyword(s):  
Nadh Oxidase ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Phosphorylated Sugars ◽  
Increased Activity ◽  
Ribulose Diphosphate Carboxylase ◽  
Glyoxylate Pathway ◽  
Pseudomonas Saccharophila

Hydrogen-dependent CO2-fixation experiments indicated the formation of several products including alanine, aspartate, phosphoglycerate, glutamate, and phosphorylated sugars by Pseudomonas saccharophila. The enzymes that are involved in the fixation are carboxydismutase, phosphoenolpyruvate carboxylase, and the malic enzyme. Ribulose diphosphate carboxylase, ribulose 5-phosphokinase, and ribose 5-phosphoisomerase show decreased activity whereas most of the tricarboxylic acid cycle enzymes and NADH oxidase show increased activity in heterotrophically grown cells. The glyoxylate pathway and permeases specific for the tricarboxylic acid cycle intermediates also vary in levels of activity according to the mode of growth. Although the oxygen tension appears to have an effect on enzyme levels during growth, the carbon source seems to be more important.

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