Influence of RpoN on isocitrate lyase activity in Pseudomonas aeruginosa

Microbiology ◽  
2010 ◽  
Vol 156 (4) ◽  
pp. 1201-1210 ◽  
Author(s):  
Jessica M. Hagins ◽  
Jessica A. Scoffield ◽  
Sang-Jin Suh ◽  
Laura Silo-Suh
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Metabolic Pathways ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Acute Infection ◽  
Carbon Sources ◽  
Pulmonary Infections ◽  
Lyase Activity ◽  
Glyoxylate Pathway ◽  
Knockout Mutation

Pseudomonas aeruginosa is the major aetiological agent of chronic pulmonary infections in patients with cystic fibrosis (CF). The metabolic pathways utilized by P. aeruginosa during these infections, which can persist for decades, are poorly understood. Several lines of evidence suggest that the glyoxylate pathway, which utilizes acetate or fatty acids to replenish intermediates of the tricarboxylic acid cycle, is an important metabolic pathway for P. aeruginosa adapted to the CF lung. Isocitrate lyase (ICL) is one of two major enzymes of the glyoxylate pathway. In a previous study, we determined that P. aeruginosa is dependent upon aceA, which encodes ICL, to cause disease on alfalfa seedlings and in rat lungs. Expression of aceA in PAO1, a P. aeruginosa isolate associated with acute infection, is regulated by carbon sources that utilize the glyoxyate pathway. In contrast, expression of aceA in FRD1, a CF isolate, is constitutively upregulated. Moreover, this deregulation of aceA occurs in other P. aeruginosa isolates associated with chronic infection, suggesting that high ICL activity facilitates adaptation of P. aeruginosa to the CF lung. Complementation of FRD1 with a PAO1 clone bank identified that rpoN negatively regulates aceA. However, the deregulation of aceA in FRD1 was not due to a knockout mutation of rpoN. Regulation of the glyoxylate pathway by RpoN is likely to be indirect, and represents a unique regulatory role for this sigma factor in bacterial metabolism.

Metabolic activity of acetate-grown Bacillus megaterium KM

1970 ◽  
Vol 16 (12) ◽  
pp. 1199-1203 ◽  
Author(s):  
A. Donawa ◽  
W. E. Inniss
Keyword(s):  
Bacillus Megaterium ◽  
Isocitrate Dehydrogenase ◽  
De Novo ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Malate Synthase ◽  
Concerted Action ◽  
Lyase Activity ◽  
Glyoxylate Pathway

Acetate-grown Bacillus megaterium KM possessed high isocitrate lyase and malate synthase activity as compared to glucose-grown cells. Chloramphenicol prevented the increase in isocitrate lyase activity when cells were transferred from glucose to acetate media, indicating that such an increase in activity was probably due to de novo protein synthesis.The affinity of the substrate, isocitrate, was greater for isocitrate dehydrogenase than for isocitrate lyase. Phosphoenolpyruvate was found to inhibit isocitrate lyase non-competitively. The concerted action of glyoxylate and oxaloacetate was capable of inhibiting isocitrate dehydrogenase. The role such factors play in the balancing of the tricarboxylic acid cycle and the glyoxylate pathway in the microorganism is considered.

Impact of glycerol-3-phosphate dehydrogenase on virulence factor production byPseudomonas aeruginosa

2014 ◽  
Vol 60 (12) ◽  
pp. 857-863 ◽  
Author(s):  
Jonathan B. Daniels ◽  
Jessica Scoffield ◽  
Jessica L. Woolnough ◽  
Laura Silo-Suh
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Metabolic Pathways ◽  
Lung Surfactant ◽  
Carbon Sources ◽  
Chronic Infections ◽  
Available Nutrients ◽  
Therapeutic Benefits ◽  
Glycerol Utilization ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Virulence Factor Production

Pseudomonas aeruginosa establishes life-long chronic infections in the cystic fibrosis (CF) lung by utilizing various adaptation strategies. Some of these strategies include altering metabolic pathways to utilize readily available nutrients present in the host environment. The airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphatidylcholine, a major component of lung surfactant. Pseudomonas aeruginosa can degrade phosphatidylcholine to glycerol and fatty acids to increase the availability of usable carbon sources in the CF lung. In this study, we show that some CF-adapted P. aeruginosa isolates utilize glycerol more efficiently as a carbon source than nonadapted isolates. Furthermore, a mutation in a gene required for glycerol utilization impacts the production of several virulence factors in both acute and chronic isolates of P. aeruginosa. Taken together, the results suggest that interference with this metabolic pathway may have potential therapeutic benefits.

scholarly journals Isocitrate Lyase Supplies Precursors for Hydrogen Cyanide Production in a Cystic Fibrosis Isolate of Pseudomonas aeruginosa

2009 ◽  
Vol 191 (20) ◽  
pp. 6335-6339 ◽  
Author(s):  
Jessica M. Hagins ◽  
Robert Locy ◽  
Laura Silo-Suh
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Growth Medium ◽  
Hydrogen Cyanide ◽  
Isocitrate Lyase ◽  
Acid Dehydrogenase ◽  
Amino Acid Dehydrogenase ◽  
Cystic Fibrosis Isolate ◽  
Glyoxylate Pathway

ABSTRACT Pseudomonas aeruginosa colonizes and can persist in the lungs of cystic fibrosis (CF) patients for decades. Adaptation of P. aeruginosa to the CF lung environment causes various genotypic and phenotypic alterations in the bacterium that facilitate persistence. We showed previously that isocitrate lyase (ICL) activity is constitutively upregulated in the P. aeruginosa CF isolate FRD1. We show here that high ICL activity in FRD1 contributes to increased hydrogen cyanide (HCN) production by this isolate. Disruption of aceA, which encodes ICL, results in reduced cyanide production by FRD1 but does not affect cyanide production in the wound isolate PAO1. Cyanide production is restored to the FRD1aceA mutant by addition of glyoxylate, a product of ICL activity, or glycine to the growth medium. Conversion of glyoxylate to glycine may provide a mechanism for increased cyanide production by P. aeruginosa growing on compounds that activate the glyoxylate pathway. Consistent with this hypothesis, disruption of PA5304, encoding a putative d-amino acid dehydrogenase (DadA), led to decreased cyanide production by FRD1. Cyanide production was restored to the FRD1dadA mutant by the addition of glycine, but not glyoxylate, to the growth medium, suggesting that loss of the ability to convert glyoxylate to glycine was associated with the dadA mutation. This was supported by increased glycine production from toluene-treated FRD1 cells with the addition of glyoxylate compared to FRD1dadA cells. This study indicates a larger role for ICL in the physiology and virulence of chronic isolates of P. aeruginosa than previously recognized.

Photo-induction sexuée du pyrénomycète Nectria galligena: influence de la mycosporine sur le rapport des activités NADPM+-socitrate déshydrogénase/isocitrate lyase

1989 ◽  
Vol 67 (2) ◽  
pp. 447-450 ◽  
Author(s):  
B. Dehorter ◽  
L. Lacoste
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Nectria Galligena ◽  
Lyase Activity ◽  
Growth Of Fungi ◽  
The Glyoxylate Cycle

The activity of two enzymes of the tricarboxylic acid cycle (NADP+-isocitrate dehydrogenase, EC 1.1.1.42) and the glyoxylate cycle (isocitrate lyase, EC 4.1.3.1) were assayed in vitro to determine the effects of darkness, light, and mycosporin (P310) on sexual morphogenesis in Nectria galligena Bres. In the absence of mycosporin, high isocitrate lyase activity was associated with vegetative growth of fungi kept in the dark. In contrast, light-induced perithecial development and mycosporin biosynthesis could be correlated with high ratios of isocitrate dehydrogenase to isocitrate lyase activity. This was confirmed by the fact that when mycosporin was added to the nutrient medium with incubation in darkness, the fertility of the fungus was partially expressed and the activity of isocitrate lyase was significantly reduced. Thus this enzyme would be repressed in vivo by mycosporin. Because of its photomimetic role in sexual differentiation and regulation of intermediate metabolism, mycosporin appears to be a biochemical transmitter of light energy required for the formation of ascocarps.

Malate synthase expression is deregulated in the Pseudomonas aeruginosa cystic fibrosis isolate FRD1

2011 ◽  
Vol 57 (3) ◽  
pp. 186-195 ◽  
Author(s):  
Jessica M. Hagins ◽  
Jessica Scoffield ◽  
Sang-Jin Suh ◽  
Laura Silo-Suh
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Carbon Sources ◽  
Malate Synthase ◽  
Current Evidence ◽  
Pathway Expression ◽  
Genes Encoding ◽  
Key Enzyme ◽  
Cystic Fibrosis Isolate ◽  
Glyoxylate Pathway

Pseudomonas aeruginosa causes chronic pulmonary infections, which can persist for decades, in patients with cystic fibrosis (CF). Current evidence suggests that the glyoxylate pathway is an important metabolic pathway for P. aeruginosa growing within the CF lung. In this study, we identified glcB, which encodes for the second key enzyme of the glyoxylate pathway, malate synthase, as a requirement for virulence of P. aeruginosa on alfalfa seedlings. While expression of glcB in PAO1, an acute isolate of P. aeruginosa, responds to some carbon sources that use the glyoxylate pathway, expression of glcB in FRD1, a CF isolate, is constitutively upregulated. Malate synthase activity is moderately affected by glcB expression and is nearly constitutive in both backgrounds, with slightly higher activity in FRD1 than in PAO1. In addition, RpoN negatively regulates glcB in PAO1 but not in FRD1. In summary, the genes encoding for the glyoxylate-specific enzymes appear to be coordinately regulated, even though they are not located within the same operon on the P. aeruginosa genome. Furthermore, both genes encoding for the glyoxylate enzymes can become deregulated during adaptation of the bacterium to the CF lung.

scholarly journals Burkholderia pseudomallei Isocitrate Lyase Is a Persistence Factor in Pulmonary Melioidosis: Implications for the Development of Isocitrate Lyase Inhibitors as Novel Antimicrobials

2009 ◽  
Vol 77 (10) ◽  
pp. 4275-4283 ◽  
Author(s):  
Erin J. van Schaik ◽  
Marina Tom ◽  
Donald E. Woods
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Causative Agent ◽  
Burkholderia Pseudomallei ◽  
Isocitrate Lyase ◽  
Bacterial Pathogens ◽  
Lung Infection ◽  
Clinical Disease ◽  
Latent Infections ◽  
Pulmonary Infections ◽  
Lyase Activity

ABSTRACT Burkholderia pseudomallei, the causative agent of melioidosis, has often been called the great “mimicker,” and clinical disease due to this organism may include acute, chronic, and latent pulmonary infections. Interestingly, chronic pulmonary melioidosis is often mistaken for tuberculosis, and this can have significant consequences, as the treatments for these two infections are radically different. The recurrent misdiagnosis of melioidosis for tuberculosis has caused many to speculate that these two bacterial pathogens use similar pathways to produce latent infections. Here we show that isocitrate lyase is a persistence factor for B. pseudomallei, and inhibiting the activity of this enzyme during experimental chronic B. pseudomallei lung infection forces the infection into an acute state, which can then be treated with antibiotics. We found that if antibiotics are not provided in combination with isocitrate lyase inhibitors, the resulting B. pseudomallei infection overwhelms the host, resulting in death. These results suggest that the inhibition of isocitrate lyase activity does not necessarily attenuate virulence as previously observed for Mycobacterium tuberculosis infections but does force the bacteria into a replicating state where antibiotics are effective. Therefore, isocitrate lyase inhibitors could be developed for chronic B. pseudomallei infections but only for use in combination with effective antibiotics.

Metabolic control in Acinetobacter sp. II. Effect of C4 versus C2 substrates on alpha-ketoglutarate dehydrogenase synthesis

1970 ◽  
Vol 16 (9) ◽  
pp. 817-820 ◽  
Author(s):  
Robert N. Sturm ◽  
Norma J. Herman ◽  
Emily J. Bell
Keyword(s):  
Control Mechanism ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Carbon Sources ◽  
Substrate Oxidation ◽  
Enzyme Synthesis ◽  
Lag Period ◽  
Alpha Ketoglutarate Dehydrogenase ◽  
Acetate Medium ◽  
Ketoglutarate Dehydrogenase

The synthesis of alpha-ketoglutarate dehydrogenase by a species of Acinetobacter growing in the presence of C4 compounds (succinate or malate) and in the presence of a C2 compound (acetate), as sole carbon sources, has been investigated. The rate of synthesis of this enzyme is increased rapidly when cells are inoculated into a succinate medium, and growth is initiated essentially without a lag period. The enzyme is synthesized after some lag period in the presence of malate and growth begins as the rate of enzyme synthesis begins to increase. On the contrary, growth begins immediately upon inoculation of the cells into an acetate medium. After a few hours of growth the level of alpha-ketoglutarate dehydrogenase begins to fall and apparent repression of synthesis occurs. These results are discussed in the light of isocitrate lyase levels in the cells at the same time periods and the evidence indicates that when levels of alpha-ketoglutarate dehydrogenase are high, those of isocitrate lyase are low. This suggests a control mechanism regulating the concurrent operation of the tricarboxylic acid cycle and the glyoxylate by-pass. Data are presented also which correlate substrate oxidation by succinate-grown cells and the cellular levels of alpha-ketoglutarate dehydrogenase.

scholarly journals Effects of Growth Mode and Pyruvate Carboxylase on Succinic Acid Production by Metabolically Engineered Strains of Escherichia coli

2002 ◽  
Vol 68 (4) ◽  
pp. 1715-1727 ◽  
Author(s):  
G. N. Vemuri ◽  
M. A. Eiteman ◽  
E. Altman
Keyword(s):  
Escherichia Coli ◽  
Succinic Acid ◽  
Pyruvate Carboxylase ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Metabolic Flexibility ◽  
Dual Phase ◽  
Anaerobic Conditions ◽  
Carboxylase Activity ◽  
Lyase Activity

ABSTRACT Escherichia coli NZN111, which lacks activities for pyruvate-formate lyase and lactate dehydrogenase, and AFP111, a derivative which contains an additional mutation in ptsG (a gene encoding an enzyme of the glucose phophotransferase system), accumulate significant levels of succinic acid (succinate) under anaerobic conditions. Plasmid pTrc99A-pyc, which expresses the Rhizobium etli pyruvate carboxylase enzyme, was introduced into both strains. We compared growth, substrate consumption, product formation, and activities of seven key enzymes (acetate kinase, fumarate reductase, glucokinase, isocitrate dehydrogenase, isocitrate lyase, phosphoenolpyruvate carboxylase, and pyruvate carboxylase) from glucose for NZN111, NZN111/pTrc99A-pyc, AFP111, and AFP111/pTrc99A-pyc under both exclusively anaerobic and dual-phase conditions (an aerobic growth phase followed by an anaerobic production phase). The highest succinate mass yield was attained with AFP111/pTrc99A-pyc under dual-phase conditions with low pyruvate carboxylase activity. Dual-phase conditions led to significant isocitrate lyase activity in both NZN111 and AFP111, while under exclusively anaerobic conditions, an absence of isocitrate lyase activity resulted in significant pyruvate accumulation. Enzyme assays indicated that under dual-phase conditions, carbon flows not only through the reductive arm of the tricarboxylic acid cycle for succinate generation but also through the glyoxylate shunt and thus provides the cells with metabolic flexibility in the formation of succinate. Significant glucokinase activity in AFP111 compared to NZN111 similarly permits increased metabolic flexibility of AFP111. The differences between the strains and the benefit of pyruvate carboxylase under both exclusively anaerobic and dual-phase conditions are discussed in light of the cellular constraint for a redox balance.

scholarly journals Microbial degradation of hydrocarbons. Catabolism of 1-phenylalkanes by Nocardia salmonicolor

1974 ◽  
Vol 140 (1) ◽  
pp. 31-45 ◽  
Author(s):  
F. Sima Sariaslani ◽  
David B. Harper ◽  
I. John Higgins
Keyword(s):  
Growth Phase ◽  
Isocitrate Lyase ◽  
Carbon Sources ◽  
Maximum Activity ◽  
Ring Cleavage ◽  
Side Chain ◽  
Energy Sources ◽  
Lag Phase ◽  
Lyase Activity ◽  
Diauxic Lag

1. Nocardia salmonicolor grew on a variety of alkanes, 1-phenylalkanes and 1-cyclo-hexylalkanes as sole carbon and energy sources. 2. Growth on 1-phenyldodecane in batch culture was diauxic. Isocitrate lyase activity was induced during lag phase, reaching a maximum activity in the first growth phase, during which both the aromatic ring and the side chain were degraded. However, 4-phenylbutyrate, 4-phenylbut-3-enoate, 4-phenylbut-2-enoate, 3-phenylpropionate, cinnamate and phenylacetate accumulated in the growth medium. These compounds disappeared at the onset of diauxic lag and four hydroxylated compounds accumulated; one was 4-(o-hydroxyphenyl)but-3-enoate and another was identified as 4-(o-hydroxyphenyl)butyrate. These compounds were utilized during the second growth phase. 3. Washed 1-phenyldodecane-grown cells oxidized acetate, cinnamate, 3,4-dihydroxyphenylacetate, homogentisate, o-, m- and p-hydroxyphenylacetate, phenylacetate, and 4-phenylbutyrate rapidly without lag. 4. Extracts of such cells rapidly oxidized homogentisate,3,4-dihydroxyphenylacetate, catechol and protocatechuate. 5. The organism grew readily on 4-phenylbutyrate, phenylacetate, o-hydroxyphenylacetate, homogentisate and 3,4-dihydroxyphenylacetate as sole carbon energy sources, but growth was slow on cinnamate and 4-phenylbut-3-enoate. 6. When cinnamate and phenylacetate were sole carbon sources for growth, phenylacetate and o-hydroxyphenylacetate respectively were detected in culture supernatants. 4-Phenylbut-3-enoate and 4-phenylbutyrate both yielded a mixture of cinnamate and phenylacetate. 7. It is proposed that 1-phenyldodecane is catabolized by ω-oxidation of the terminal methyl group, side-chain β-oxidation to 4-phenylbutyrate, both β- and α-oxidation to phenylacetic acid, hydroxylation to homogentisate via o-hydroxyphenylacetate and ring cleavage to maleylacetoacetate. Catabolism via 3,4-dihydroxyphenylacetate may also occur. 8. Growth on 1-phenylnonane was also diauxic and cinnamic acid, phenylpropionic acid, benzoic acid and hydroxyphenylpentanoic acid accumulated in the medium. Respirometric data and ring-cleavage enzyme activities showed similar patterns to those obtained after growth on 1-phenyldodecane. The results suggest that the main catabolic routes for 1-phenyldodecane and 1-phenylnonane may converge at cinnamate. 9. Possible reasons for diauxie are discussed.

scholarly journals Pseudomonas aeruginosa transcriptome adaptations from colonization to biofilm infection of skin wounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter D’Arpa ◽  
S. L. Rajasekhar Karna ◽  
Tsute Chen ◽  
Kai P. Leung
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbon Source ◽  
Wound Infection ◽  
Glyoxylate Cycle ◽  
Acute Infection ◽  
Carbon Sources ◽  
Myeloid Cell ◽  
Carbon Utilization ◽  
Branched Chain ◽  
Biofilm Infection

AbstractIn burn patients Pseudomonas aeruginosa infection is a major cause of morbidity. Analysis of the pathogen’s gene expression as it transitions from colonization to acute and then biofilm wound infection may provide strategies for infection control. Toward this goal, we seeded log-phase P. aeruginosa (PAO1) into 3-day-old, full-thickness excision wounds (rabbit ear) and harvested the bacteria during colonization (Hrs 2 and 6), acute infection (Hr 24), and biofilm infection (Days 5 and 9) for transcriptome analysis (RNA-Seq). After 2–6 h in the wound, genes for metabolism and cell replication were down-regulated while wound-adaptation genes were up-regulated (vs. expression in log-phase culture). As the infection progressed from acute to biofilm infection, more genes became up-regulated than down-regulated, but the down-regulated genes enriched in more pathways, likely because the genes and pathways that bacteria already colonizing wounds up-regulate to establish biofilm infection are less known. Across the stages of infection, carbon-utilization pathways shifted. During acute infection, itaconate produced by myeloid cells appears to have been a carbon source because myeloid cell infiltration and the expression of the host gene, ACOD1, for itaconate production peaked coincidently with the expression of the PAO1 genes for itaconate transport and catabolism. Additionally, branched-chain amino acids are suggested to be a carbon source in acute infection and in biofilm infection. In biofilm infection, fatty acid degradation was also up-regulated. These carbon sources feed into the glyoxylate cycle that was coincidently up-regulated, suggesting it provided the precursors for P. aeruginosa to synthesize macromolecules in establishing wound infection.

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