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

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

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

OBJECTIVETo investigate the clinical, biochemical and genetic profiles of 28 Chinese patients with glutaric aciduria type 1.

METHODTwenty-eight patients with glutaric aciduria type 1 seen in the Department of Pediatrics, Peking University First Hospital from July 2003 to October 2013 were studied. The data of clinical course, laboratory examinations, cranial MRI and GCDH gene mutations of the patients were analyzed.

RESULT(1) Three cases were detected by newborn screening, and the other patients were diagnosed at the age of 2 months to 17 years. (2) 22 patients (79%) were infant onset cases with psychomotor retardation, dystonia, seizures, athetosis, recurrent vomiting, drowsiness or feeding difficulty. Only two of the 22 patients with infant onset got normal intelligence and movement after treatment. Twenty of them were improved slowly with delayed development, dystonia and other neurological problems. Three patients (11%) had late onset. They had motor regression, headache and seizure at the age of 8, 9 and 17 years, respectively. Rapid improvement was observed after treatment. (3) Cranial MRI has been checked in 23 patients; 22 of them showed characteristic widening of the Sylvian fissure, abnormalities of the basal ganglia, leukoencephalopathy and brain atrophy. Thirty-five mutations in GCDH gene of the patients were identified; c.148T>C (p.W50R) was the most common mutation with the frequency of 7.7%; 6 mutations (c.628A>G, c.700C>T, c.731G>T, c.963G>C, c.1031C>T and c.1109T>C) were novel.

CONCLUSIONGlutaric aciduria type 1 usually induced neurological deterioration resulting in severe psychomotor retardation and dystonia. Most of our patients were clinically diagnosed. Patients with early onset usually remained having neurological damage. Phenotype and genotype correlation has not been found in the patients. Neonatal screening for organic acidurias should be expanded in China.

Age of Onset ; Amino Acid Metabolism, Inborn Errors ; diagnosis ; genetics ; metabolism ; Brain Diseases, Metabolic ; diagnosis ; genetics ; metabolism ; DNA Mutational Analysis ; Follow-Up Studies ; Gas Chromatography-Mass Spectrometry ; Glutarates ; urine ; Glutaryl-CoA Dehydrogenase ; deficiency ; genetics ; metabolism ; Humans ; Infant, Newborn ; Intellectual Disability ; etiology ; pathology ; Magnetic Resonance Imaging ; Movement Disorders ; etiology ; pathology ; Mutation ; Neonatal Screening ; methods ; Retrospective Studies

Amino Acid Metabolism, Inborn Errors ; urine ; Female ; Glutarates ; urine ; Humans ; Infant ; Male

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

Amino Acid Metabolism, Inborn Errors ; diagnosis ; genetics ; therapy ; Brain ; diagnostic imaging ; metabolism ; pathology ; Brain Diseases, Metabolic ; diagnosis ; genetics ; therapy ; Child, Preschool ; Diagnosis, Differential ; Glutarates ; metabolism ; Glutaryl-CoA Dehydrogenase ; deficiency ; genetics ; Humans ; Infant ; Infant, Newborn ; Lysine ; metabolism ; Magnetic Resonance Imaging ; Multiple Acyl Coenzyme A Dehydrogenase Deficiency ; diagnosis ; genetics ; therapy ; Mutation ; Neonatal Screening ; methods ; Radiography