Pyroptosis ; Ketoglutaric Acids ; Gasdermins ; Intracellular Signaling Peptides and Proteins/metabolism* ; Caspases/metabolism* ; Inflammasomes/metabolism*

L-glutamic acid is the world's largest bulk amino acid product that is widely used in the food, pharmaceutical and chemical industries. Using Corynebacterium glutamicum G01 as the starting strain, the fermentation by-product alanine content was firstly reduced by knocking out the gene encoding alanine aminotransferase (alaT), a major by-product related to alanine synthesis. Secondly, since the α-ketoglutarate node carbon flow plays an important role in glutamate synthesis, the ribosome-binding site (RBS) sequence optimization was used to reduce the activity of α-ketoglutarate dehydrogenase and enhance the glutamate anabolic flow. The endogenous conversion of α-ketoglutarate to glutamate was also enhanced by screening different glutamate dehydrogenase. Subsequently, the glutamate transporter was rationally desgined to improve the glutamate efflux capacity. Finally, the fermentation conditions of the strain constructed using the above strategy were optimized in 5 L fermenters by a gradient temperature increase combined with a batch replenishment strategy. The glutamic acid production reached (135.33±4.68) g/L, which was 41.2% higher than that of the original strain (96.53±2.32) g/L. The yield was 55.8%, which was 11.6% higher than that of the original strain (44.2%). The combined strategy improved the titer and the yield of glutamic acid, which provides a reference for the metabolic modification of glutamic acid producing strains.
Glutamic Acid ; Corynebacterium glutamicum/genetics* ; Ketoglutaric Acids ; Metabolic Engineering ; Alanine

Silver nanoparticles (AgNPs) is known as one of the most valuable metal nanoparticles in antibacterial and anticancer application. AgNPs-resistant bacteria has been documented, but it is unclear whether cancer cells can also escape the anti-cancer effect of AgNPs. In this study, we aimed to investigate this phenomenon and its underlying mechanism. The antibacterial activity and cytotoxicity of AgNPs were measured in the presence of HeLa cell metabolites. The status of AgNPs in the system associated with metabolites were characterized by UV-Vis, Zetasizer Nano ZS, and transmission electron microscopy. Non-targeted metabolomics was used to reveal the metabolites components that bind with AgNPs. HeLa cells were injected intraperitoneally to establish the tumor-bearing mice model, and the stability of AgNPs in mice serum was analyzed. The results manifested that HeLa cell metabolites inhibited the anticancer and antibacterial effects of AgNPs in a dose-dependent manner by causing AgNPs aggregation. Effective metabolites that inhibited the biological activity of AgNPs were stable in 100 ℃, insoluble in chloroform, containing sulfur elements, and had a molecular weight less than 1 kDa in molecular weight. There were 115 compounds bound with AgNPs. In vitro experiments showed that AgNPs aggregation occurred only when the concentration of α-ketoglutarate (AKG) and glutathione (GSH) together reached a certain threshold. Interestingly, the concentration of AKG and GSH in HeLa cellular metabolites was 10 and 6 times higher than that in normal cervical epithelial cells, respectively, which explained why the threshold was reached. Furthermore, the stability of AgNPs in the serum of tumor-bearing mice decreased by 20% (P < 0.05) compared with the healthy mice. In conclusion, our study demonstrates that HeLa cells escaped the anti-cancer effect of AgNPs through the synergistic effect of AKG and GSH, suggesting the need to develop strategies to overcome this limitation.
Humans ; Animals ; Mice ; HeLa Cells ; Silver/pharmacology* ; Ketoglutaric Acids/pharmacology* ; Metal Nanoparticles ; Anti-Bacterial Agents/pharmacology* ; Glutathione ; Microbial Sensitivity Tests

OBJECTIVETo observe metabolomic changes in urine of chronic superficial gastritis (CSG) patients with Pi-qi deficiency syndrome (PQDS) or Pi-Wei dampness-heat syndrome (PWDHS), thereby providing scientific evidence for syndrome typing of them.

METHODSUrine samples were collected from CSG patients with PQDS/PWDHS and healthy volunteers, 10 in each group. Proton nuclear magnetic resonance spectroscopy (1H-NMR) based metabonomic analysis was performed on urine samples. Contents of related biomarkers were analyzed by principal component analysis (PCA), partial least square discriminant analysis (PLS-DA), and urivariate statistical analysis.

RESULTSPLS-DA analysis showed that metabolites among CSG patients with PQDS/PWDHS and healthy volunteers could be mutually distinguished. Seven differentially identified metabolites were screened from urines of CSG patients with PQDS and healthy volunteers included glutamate, methionine, α-oxoglutarate, dimethylglycine, creatinine, taurine, and glucose. Four differentially identified metabolites were screened from urines of CSG patients with PWDHS and healthy volunteers included 2-hydroxybutyric acid, trimethylamine oxide, taurine, and hippuric acid. Eleven differentially identified metabolites were screened from urines of CSG patients with PQDS and PWDHS included fucose, β-hydroxybutyric acid, alanine, glutamate, methionine, succinic acid, citric acid, creatinine, glucose, hippuric acid, and lactic acid.

CONCLUSIONThe metabolic differences of CSG patients PQDS and PWDHS mainly manifested in glycometabolism, lipid metabolism, and amino acids catabolism, and 1H-NMR based metabonomics may be used in classified study of Chinese medical syndrome typing.

Biomarkers ; urine ; Discriminant Analysis ; Gastritis ; urine ; Hot Temperature ; Humans ; Hydroxybutyrates ; Ketoglutaric Acids ; Least-Squares Analysis ; Medicine, Chinese Traditional ; Metabolome ; physiology ; Metabolomics ; Principal Component Analysis ; Proton Magnetic Resonance Spectroscopy ; Qi ; Syndrome

We produced α-ketoglutaric acid (α-KG) from L-glutamic acid, using enzymatic transformation approach with L-glutamate oxidase (LGOX). First, wild strain Streptomyces sp. FMME066 was mutated with NTG, a genetically stable mutant Streptomyces sp. FMME067 was obtained. Under the optimal nutrition conditions with fructose 10 g/L, peptone 7.5 g/L, KH2PO4 1 g/L and CaCl2 0.05 g/L, the maximum LGOX activity reached 0.14 U/mL. The LGOX was stable to pH and temperature, and Mn2+ had a stimulating effect. Finally, after 24 h enzymatic conversion under the optimal conditions, the maximum titer of α-KG reached 38.1 g/L from 47 g/L L-glutamic acid. Enzymatic transformation by LGOX is a potential approach for α-KG production.
Amino Acid Oxidoreductases ; metabolism ; Fermentation ; Glutamic Acid ; metabolism ; Ketoglutaric Acids ; metabolism ; Streptomyces ; genetics ; metabolism

To investigate the intervention effects of Morinda officinalis How. on 'Kidney-yang deficiency syndrome' induced by hydrocortisone in rats, the metabolic profiles of rat urine were characterized using proton nuclear magnetic resonance and principal component analysis (PCA) was applied to study the trajectory of urinary metabolic phenotype of rats with 'Kidney-yang deficiency syndrome' under administration of M. officinalis at different time points. Meanwhile, the intervention effects of M. officinalis on urinary metabolic potential biomarkers associated with 'Kidney-yang deficiency syndrome' were also discussed. The experimental results showed that in accordance to the increased time of administration, an obvious tendency was observed that clustering of the treatment group moved gradually closed to that of the control group. Eight potential biomarkers including citrate, succinate, alpha-ketoglutarate, lactate, betaine, sarcosine, alanine and taurine were definitely up- or down-regulated. In conclusion, the effectiveness of M. oficinalis on 'Kidney-yang deficiency syndrome' is proved using the established metabonomic method and the regulated metabolic pathways involve energy metabolism, transmethylation and transportation of amine. Meanwhile, the administration of M. officinalis can alleviate the kidney impairment induced by 'Kidney-yang deficiency syndrome'.
Alanine ; urine ; Animals ; Betaine ; urine ; Biomarkers ; urine ; Citric Acid ; urine ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Hydrocortisone ; Ketoglutaric Acids ; urine ; Kidney Diseases ; chemically induced ; urine ; Lactic Acid ; urine ; Magnetic Resonance Spectroscopy ; Male ; Metabolomics ; methods ; Morinda ; chemistry ; Plants, Medicinal ; chemistry ; Principal Component Analysis ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sarcosine ; urine ; Succinic Acid ; urine ; Taurine ; urine ; Yang Deficiency ; chemically induced ; urine

Alpha-ketogluratate is one of the key intermediates in the TCA cycle, playing an important role in the connection of carbon and nitrogen metabolism. This article aims at stating recent research progress in the production of alpha-ketoglutarate by microbial fermentation. First, a large group of microbes have been screened to accumulate alpha-ketoglutarate including prokaryotes and eukaryotes. Second, physiological characterization of over-accumulation of alpha-ketoglutarate is caused by thiamine defect and nitrogen starvation. Third, the process of fermentation was controlled and optimized by the manipulation of pH, dissolved oxygen and cofactors. Fourth, many metabolic engineering strategies were also presented for alpha-ketoglutarate production focusing on regeneration of cofactor and manipulation of the pathway. Last, we discussed the limitation of current progress and proposed the future research needs for microbial production of alpha-ketoglutarate.
Bacteria ; growth & development ; metabolism ; Fermentation ; Fungi ; growth & development ; metabolism ; Industrial Microbiology ; methods ; Ketoglutaric Acids ; metabolism ; Metabolic Engineering ; Yarrowia ; growth & development ; metabolism

OBJECTIVETo investigate the toxic effects of Glucoside Tripterygium total on rats with nuclear magnetic resonance (NMR)-based metabonomic method.

METHODThe influence of intragastric administration of Glucoside Tripterygium total suspension at two different doses on endogenetic metabolites in normal rat urine was determined with bio-NMR method then analyzed by pattern recognition technique and partial least-squares discriminant analysis (PLS-DA). Histopathological analysis was carried out.

RESULTEscalations of concentrations of urinary taurine, TMAO and glucose as well as reductions of concentrations of urinary citrate and 2-oxoglutarate were found by analysis of the 1H-NMR spectra, which was coincident with the result of histopathological analysis. The result of pathological examination indicated that pathologic change was not observed in nephridial tissue, but there were obvious changes in hepatic tissue.

CONCLUSIONThe urinary metabomic spectra were closely associated with the hepatic toxicity, which manifested the mitochondrial dysfunctions, the abnormal energy metabolism in TCA cycle as well as the abnormal glucose metabolism.

Animals ; Citric Acid ; urine ; Enteral Nutrition ; Glucose ; metabolism ; Glucosides ; administration & dosage ; Ketoglutaric Acids ; urine ; Least-Squares Analysis ; Liver ; drug effects ; metabolism ; pathology ; Magnetic Resonance Spectroscopy ; methods ; Metabolomics ; Methylamines ; urine ; Plant Extracts ; administration & dosage ; Rats ; Tablets ; administration & dosage ; Taurine ; urine ; Tripterygium ; chemistry

OBJECTIVETo highlight recent researches which may show promise for histomolecular classification and new treatments for gliomas.

DATA SOURCESAll articles cited in this review were mainly searched from PubMed, which were published in English from 1996 to 2010.

STUDY SELECTIONOriginal articles and critical reviews selected were relevant to the isocitrate dehydrogenase-1/2 mutation in gliomas and other tumors.

RESULTSExtraordinary high rates of somatic mutations in isocitrate dehydrogenase-1/2 occur in the majority of World Health Organization grade II and grade III gliomas as well as grade IV secondary glioblastomas. Isocitrate dehydrogenase-1/2 mutations are associated with younger age at diagnosis and a better prognosis in patients with mutated tumors. The functional role of isocitrate dehydrogenase-1/2 mutations in the pathogenesis of gliomas is still unclear.

CONCLUSIONIsocitrate dehydrogenase-1/2 mutations define a specific subtype of gliomas and may have great significance in the diagnosis, prognosis, and treatment of patients with these tumors.

Adult ; Age Factors ; Brain Neoplasms ; genetics ; pathology ; Genes, p53 ; Glioma ; genetics ; pathology ; Glutarates ; metabolism ; Humans ; Isocitrate Dehydrogenase ; genetics ; physiology ; Ketoglutaric Acids ; metabolism ; Middle Aged ; Mutation ; NADP ; metabolism ; Neoplasm Grading ; Prognosis

PURPOSE: A family of organic anion transporters (OAT) has been identified, and several isoforms have been reported. The regulatory mechanisms of OATs functions, however, still remain to be elucidated. The rat OAT1 contributes to move a number of negatively-charged organic compounds between cells and their extracellular milieu. Caveolin (Cav) also plays a role in membrane transport. To address this issue, we investigated the protein-protein interaction between rOAT1 and Cav-1. METHODS: The expressions of rOAT1 and Cav-1 (mRNA and protein) were evaluated using RT-PCR and Western blot analysis. The localization of rOAT1 and Cav-1 was determined in the caveolae-rich membrane fraction isolated by sucrose density gradient ultra-centrifugation. For the direct binding between the rOAT1 and Cav-1 proteins, the immuno-precipitation method and confocal microscopy were employed. To perform functional analysis, a Xenopus oocytes expression system with the antisense oligonucleotides (ODN) technique was used. RESULTS: The expressions of rOAT1 and Cav-1 were detected in the kidney. The caveolae-rich membranous fractions from the kidney contained both rOAT1 and Cav-1 in the same fractions. The immuno-precipitation experiments showed the formation of a complex between the rOAT1 and Cav-1. The confocal microscopy using primary cultured renal proximal epithelial cells also supported the co-localization of rOAT1 and Cav-1 at the plasma membrane. The uptake function of rOAT1, as assessed by using a Xenopus oocytes expression system, was inhibited by the Xenopus Cav-1 antisense ODN. CONCLUSION: rOAT1 co-localizes with caveolin-1 in the caveolae, and caveolin-1 plays an important role in regulating the function of rOAT1.
Animals ; Avena ; Blotting, Western ; Caveolae ; Caveolin 1 ; Cell Membrane ; Epithelial Cells ; Humans ; Ketoglutaric Acids ; Kidney ; Kidney Tubules, Proximal ; Membranes ; Microscopy, Confocal ; Oligonucleotides, Antisense ; Oocytes ; Organic Anion Transporters ; Protein Isoforms ; Proteins ; Rats ; Sucrose ; Xenopus