Oxygenated monoterpenes citral and carvacrol cause oxidative damage in Escherichia coli without the involvement of tricarboxylic acid cycle and Fenton reaction

2014 ◽  
Vol 189 ◽  
pp. 126-131 ◽  
Author(s):  
Beatriz Chueca ◽  
Rafael Pagán ◽  
Diego García-Gonzalo
Keyword(s):  
Escherichia Coli ◽  
Oxidative Damage ◽  
Fenton Reaction ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Oxygenated Monoterpenes

Metabolic flux analysis of Escherichia coli in glucose-limited continuous culture. I. Growth-rate-dependent metabolic efficiency at steady state

Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 693-706 ◽  
Author(s):  
Anke Kayser ◽  
Jan Weber ◽  
Volker Hecht ◽  
Ursula Rinas
Keyword(s):  
Escherichia Coli ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Linear Increase ◽  
Carbon Substrate ◽  
Carbon Dioxide Evolution ◽  
Continuous Cultures ◽  
Acid Cycle ◽  
Biomass Formation ◽  
Carbon Supply

The Escherichia coli K-12 strain TG1 was grown at 28 °C in aerobic glucose-limited continuous cultures at dilution rates ranging from 0·044 to 0·415 h−1. The rates of biomass formation, the specific rates of glucose, ammonium and oxygen uptake and the specific carbon dioxide evolution rate increased linearly with the dilution rate up to 0·3 h−1. At dilution rates between 0·3 h−1 and 0·4 h−1, a strong deviation from the linear increase to lower specific oxygen uptake and carbon dioxide evolution rates occurred. The biomass formation rate and the specific glucose and ammonium uptake rates did not deviate that strongly from the linear increase up to dilution rates of 0·4 h−1. An increasing percentage of glucose carbon flow towards biomass determined by a reactor mass balance and a decreasing specific ATP production rate concomitant with a decreasing adenylate energy charge indicated higher energetic efficiency of carbon substrate utilization at higher dilution rates. Estimation of metabolic fluxes by a stoichiometric model revealed an increasing activity of the pentose phosphate pathway and a decreasing tricarboxylic acid cycle activity with increasing dilution rates, indicative of the increased NADPH and precursor demand for anabolic purposes at the expense of ATP formation through catabolic activities. Thus, increasing growth rates first result in a more energy-efficient use of the carbon substrate for biomass production, i.e. a lower portion of the carbon substrate is channelled into the respiratory, energy-generating pathway. At dilution rates above 0·4 h−1, close to the wash-out point, respiration rates dropped sharply and accumulation of glucose and acetic acid was observed. Energy generation through acetate formation yields less ATP compared with complete oxidation of the sugar carbon substrate, but is the result of maximized energy generation under conditions of restrictions in the tricarboxylic acid cycle or in respiratory NADH turnover. Thus, the data strongly support the conclusion that, in aerobic glucose-limited continuous cultures of E. coli TG1, two different carbon limitations occur: at low dilution rates, cell growth is limited by cell-carbon supply and, at high dilution rates, by energy-carbon supply.

scholarly journals Role of Phosphoenolpyruvate in the NADP-Isocitrate Dehydrogenase and Isocitrate Lyase Reaction in Escherichia coli

2006 ◽  
Vol 189 (3) ◽  
pp. 1176-1178 ◽  
Author(s):  
Tadashi Ogawa ◽  
Keiko Murakami ◽  
Hirotada Mori ◽  
Nobuyoshi Ishii ◽  
Masaru Tomita ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Isocitrate Dehydrogenase ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Glyoxylate Shunt ◽  
Acid Cycle ◽  
Uncompetitive Inhibition

ABSTRACT Phosphoenolpyruvate inhibited Escherichia coli NADP-isocitrate dehydrogenase allosterically (Ki of 0.31 mM) and isocitrate lyase uncompetitively (Ki ′ of 0.893 mM). Phosphoenolpyruvate enhances the uncompetitive inhibition of isocitrate lyase by increasing isocitrate, which protects isocitrate dehydrogenase from the inhibition, and contributes to the control through the tricarboxylic acid cycle and glyoxylate shunt.

Evaluation of anaerobic glucose utilization by Escherichia coli strains with impaired fermentation ability upon respiration with external and internal electron acceptor

2020 ◽  
Vol 36 (3) ◽  
pp. 25-33
Author(s):  
A.Yu. Gulevich ◽  
V.G. Debabov
Keyword(s):  
Escherichia Coli ◽  
Electron Acceptor ◽  
Glucose Utilization ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Nitrate Respiration ◽  
Activity Levels ◽  
Ammonium Ions ◽  
Acid Fermentation ◽  
Acid Cycle

The characteristics of anaerobic glucose utilization and metabolite production by recombinant Escherichia coli strains with impaired fermentation ability upon respiration with pyruvate as an internal and nitrate as an external electron acceptor have been studied. It was found that respiration processes utilizing pyruvic acid as an endogenous electron acceptor and leading to the lactate and alanine formation were capable of mutual interference. After elimination of ammonium ions from the medium, the native activity levels of respiratory lactate dehydrogenases Did and LldD in E. coli strains deficient in the mixed acid fermentation pathways can almost completely compensate for the loss of activity of respiratory alanine dehydrogenase DadA, but are insufficient to maintain the entire intracellular redox balance. The addition of nitrate ions in the medium abolished alanine production by the strains despite the availability of ammonium ions, while the functionality of respiratory reduction of endogenous pyruvate to lactate retained in the studied strains even in the presence of a strong exogenous oxidant. Respiration with external electron acceptor provoked the activation of the oxidative tricarboxylic acid cycle in the strains. Anaerobic glucose utilization by the strain with interrupted tricarboxylic acid cycle increased during nitrate respiration, but remained restricted by the excessive generation of reducing equivalents in the residual reactions of the cycle. Escherichia coli, glucose, fermentation, respiration, pyruvate, lactate, alanine, nitrate, ammonium. The work was supported by a grant from the Russian Foundation for Basic Research (project #18-04-01222).

scholarly journals [13C]propionate oxidation in wild-type and citrate synthase mutant Escherichia coli: evidence for multiple pathways of propionate utilization

1993 ◽  
Vol 291 (3) ◽  
pp. 927-932 ◽  
Author(s):  
C T Evans ◽  
B Sumegi ◽  
P A Srere ◽  
A D Sherry ◽  
C R Malloy
Keyword(s):  
Escherichia Coli ◽  
Citrate Synthase ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Spin Coupling ◽  
Wild Type ◽  
Acid Cycle ◽  
E Coli ◽  
Cell Extracts ◽  
In Cells

The metabolism of propionate was examined in wild-type Escherichia coli and cells lacking citrate synthase by high-resolution 13C n.m.r. Spectra of cell extracts from wild-type E. coli show that glutamate becomes highly enriched in 13C when 13C-enriched propionate is the sole carbon source. No glutamate labelling was detected when the tricarboxylic acid cycle was blocked either by deletion of citrate synthase or by inhibition of succinate dehydrogenase by malonate. The 13C fractional enrichment in glutamate C-2, C-3 and C-4 in wild-type cells was quantitatively and qualitatively different when [2-13C]propionate as opposed to [3-13C]propionate was supplied. Approximately equal labelling occurred in the C-2, C-3 and C-4 positions of glutamate when [3-13C]propionate was available, and multiplets due to carbon-carbon spin-spin coupling were observed. However, in cells supplied with [2-13C]propionate, very little 13C appeared in the glutamate C-4 position, and the remaining glutamate resonances all appeared as singlets. The unequal and non-identical labelling of glutamate in cells supplied with [2-13C]- as opposed to [3-13C]propionate is consistent with the utilization of propionate by E. coli via two pathways, oxidation of propionate to pyruvate and carboxylation of propionate to succinate. These intermediates are further metabolized to glutamate by the action of the tricarboxylic acid cycle. The existence of an organized tricarboxylic acid cycle is discussed as a consequence of the ability to block utilization of propionate in tricarboxylic acid-cycle-defective E. coli.

scholarly journals Indole-3-acetic acid regulates the central metabolic pathways in Escherichia coli

Microbiology ◽  
2006 ◽  
Vol 152 (8) ◽  
pp. 2421-2431 ◽  
Author(s):  
C. Bianco ◽  
E. Imperlini ◽  
R. Calogero ◽  
B. Senatore ◽  
P. Pucci ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metabolic Pathways ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Mrna Levels ◽  
Glyoxylate Shunt ◽  
Acetyl Coa ◽  
Acid Cycle ◽  
E Coli ◽  
K 12

The physiological changes induced by indoleacetic acid (IAA) treatment were investigated in the totally sequenced Escherichia coli K-12 MG1655. DNA macroarrays were used to measure the mRNA levels for all the 4290 E. coli protein-coding genes; 50 genes (1.1 %) exhibited significantly different expression profiles. In particular, genes involved in the tricarboxylic acid cycle, the glyoxylate shunt and amino acid biosynthesis (leucine, isoleucine, valine and proline) were up-regulated, whereas the fermentative adhE gene was down-regulated. To confirm the indications obtained from the macroarray analysis the activity of 34 enzymes involved in central metabolism was measured; this showed an activation of the tricarboxylic acid cycle and the glyoxylate shunt. The malic enzyme, involved in the production of pyruvate, and pyruvate dehydrogenase, required for the channelling of pyruvate into acetyl-CoA, were also induced in IAA-treated cells. Moreover, it was shown that the enhanced production of acetyl-CoA and the decrease of NADH/NAD+ ratio are connected with the molecular process of the IAA response. The results demonstrate that IAA treatment is a stimulus capable of inducing changes in gene expression, enzyme activity and metabolite level involved in central metabolic pathways in E. coli.

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