scholarly journals The deficient carbohydrate metabolic pathways and the incomplete tricarboxylic acid cycle in an obligately autotrophic hydrogen-oxidizing bacterium.

1982 ◽  
Vol 46 (9) ◽  
pp. 2341-2345 ◽  
Author(s):  
Hirotaka SHIBA ◽  
Toshiyuki KAWASUMI ◽  
Yasuo IGARASHI ◽  
Tohru KODAMA ◽  
Yasuji MINODA
Microbiology ◽  
2006 ◽  
Vol 152 (8) ◽  
pp. 2421-2431 ◽  
Author(s):  
C. Bianco ◽  
E. Imperlini ◽  
R. Calogero ◽  
B. Senatore ◽  
P. Pucci ◽  
...  

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.


mSystems ◽  
2021 ◽  
Author(s):  
Magdalena Modrzejewska ◽  
Adam Kawalek ◽  
Aneta Agnieszka Bartosik

This study shows that BsrA, a LysR-type transcriptional regulator from Pseudomonas aeruginosa , previously identified as a repressor of biofilm synthesis, is part of an intricate global regulatory network. BsrA acts directly and/or indirectly as the repressor and/or activator of genes from vital metabolic pathways (e.g., pyruvate, acetate, and tricarboxylic acid cycle) and is involved in control of transport functions and the formation of surface appendages.


Author(s):  
Jeroen G Koendjbiharie ◽  
Richard van Kranenburg ◽  
Servé W M Kengen

ABSTRACT At the junction between the glycolysis and the tricarboxylic acid cycle—as well as various other metabolic pathways—lies the phosphoenolpyruvate (PEP)-pyruvate-oxaloacetate node (PPO-node). These three metabolites form the core of a network involving at least eleven different types of enzymes, each with numerous subtypes. Obviously, no single organism maintains each of these eleven enzymes; instead, different organisms possess different subsets in their PPO-node, which results in a remarkable degree of variation, despite connecting such deeply conserved metabolic pathways as the glycolysis and the tricarboxylic acid cycle. The PPO-node enzymes play a crucial role in cellular energetics, with most of them involved in (de)phosphorylation of nucleotide phosphates, while those responsible for malate conversion are important redox enzymes. Variations in PPO-node therefore reflect the different energetic niches that organisms can occupy. In this review, we give an overview of the biochemistry of these eleven PPO-node enzymes. We attempt to highlight the variation that exists, both in PPO-node compositions, as well as in the roles that the enzymes can have within those different settings, through various recent discoveries in both bacteria and archaea that reveal deviations from canonical functions.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yiyong Wei ◽  
Donghang Zhang ◽  
Jin Liu ◽  
Mengchan Ou ◽  
Peng Liang ◽  
...  

Abstract Background Metabolic status can be impacted by general anesthesia and surgery. However, the exact effects of general anesthesia and surgery on systemic metabolome remain unclear, which might contribute to postoperative outcomes. Methods Five hundred patients who underwent abdominal surgery were included. General anesthesia was mainly maintained with sevoflurane. The end-tidal sevoflurane concentration (ETsevo) was adjusted to maintain BIS (Bispectral index) value between 40 and 60. The mean ETsevo from 20 min after endotracheal intubation to 2 h after the beginning of surgery was calculated for each patient. The patients were further divided into low ETsevo group (mean − SD) and high ETsevo group (mean + SD) to investigate the possible metabolic changes relevant to the amount of sevoflurane exposure. Results The mean ETsevo of the 500 patients was 1.60% ± 0.34%. Patients with low ETsevo (n = 55) and high ETsevo (n = 59) were selected for metabolomic analysis (1.06% ± 0.13% vs. 2.17% ± 0.16%, P < 0.001). Sevoflurane and abdominal surgery disturbed the tricarboxylic acid cycle as identified by increased citrate and cis-aconitate levels and impacted glycometabolism as identified by increased sucrose and D-glucose levels in these 114 patients. Glutamate metabolism was also impacted by sevoflurane and abdominal surgery in all the patients. In the patients with high ETsevo, levels of L-glutamine, pyroglutamic acid, sphinganine and L-selenocysteine after sevoflurane anesthesia and abdominal surgery were significantly higher than those of the patients with low ETsevo, suggesting that these metabolic changes might be relevant to the amount of sevoflurane exposure. Conclusions Sevoflurane anesthesia and abdominal surgery can impact principal metabolic pathways in clinical patients including tricarboxylic acid cycle, glycometabolism and glutamate metabolism. This study may provide a resource data for future studies about metabolism relevant to general anaesthesia and surgeries. Trial registration www.chictr.org.cn. identifier: ChiCTR1800014327.


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