Citric Acid Cycle ; Citric Acid ; Malates/metabolism* ; Citrates/metabolism* ; Aspartic Acid/metabolism*

OBJECTIVE: To explore the amino acid metabolomics characteristics of myeloid-derived suppressor cells (MDSCs) in mice with sepsis induced by the cecal ligation and puncture (CLP). METHODS: The sepsis mouse model was prepared by CLP, and the mice were randomly divided into a sham operation group (sham group, n = 10) and a CLP model group (n = 10). On the 7th day after the operation, 5 mice were randomly selected from the surviving mice in each group, and the bone marrow MDSCs of the mice were isolated. Bone marrow MDSCs were separated to measure the oxygen consumption rate (OCR) by using Agilent Seahorse XF technology and to detect the contents of intracellular amino acids and oligopeptides through ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) technology. Different metabolites and potential biomarkers were analyzed by univariate statistical analysis and multivariate statistical analysis. The major metabolic pathways were enriched using the small molecular pathway database (SMPDB). RESULTS: The proportion of MDSCs in the bone marrow of CLP group mice (75.53% ± 6.02%) was significantly greater than that of the sham group (43.15%± 7.42%, t = 7.582, P < 0.001), and the basal respiratory rate [(50.03±1.20) pmol/min], maximum respiration rate [(78.07±2.57) pmol/min] and adenosine triphosphate (ATP) production [(25.30±1.21) pmol/min] of MDSCs in the bone marrow of CLP group mice were significantly greater than the basal respiration rate [(34.53±0.96) pmol/min, (t = 17.41, P < 0.001)], maximum respiration rate [(42.57±1.87) pmol/min, (t = 19.33, P < 0.001)], and ATP production [(12.63±0.96) pmol/min, (t = 14.18, P < 0.001)] of sham group. Leucine, threonine, glycine, etc. were potential biomarkers of septic MDSCs (all P < 0.05). The increased amino acids were mainly enriched in metabolic pathways, such as malate-aspartate shuttle, ammonia recovery, alanine metabolism, glutathione metabolism, phenylalanine and tyrosine metabolism, urea cycle, glycine and serine metabolism, β-alanine metabolism, glutamate metabolism, arginine and proline metabolism. CONCLUSION The enhanced mitochondrial oxidative phosphorylation, malate-aspartate shuttle and alanine metabolism in MDSCs of CLP mice may provide raw materials for mitochondrial aerobic respiration, thereby promoting the immunosuppressive function of MDSCs. Blocking the above metabolic pathways may reduce the risk of secondary infection in sepsis and improve the prognosis.
Adenosine Triphosphate/metabolism* ; Alanine/metabolism* ; Animals ; Aspartic Acid/metabolism* ; Biomarkers/metabolism* ; Chromatography, Liquid ; Glycine/metabolism* ; Malates/metabolism* ; Mice ; Myeloid-Derived Suppressor Cells/metabolism* ; Sepsis/complications* ; Tandem Mass Spectrometry

Aluminum (Al) is the most abundant metal element in the earth's crust. On acid soils, at pH 5.5 or lower, part of insoluble Al-containing minerals become solubilized into soil solution, with resultant highly toxic effects on plant growth and development. Nevertheless, some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity. One such well-documented mechanism is the Al-induced secretion of organic acid anions, including citrate, malate, and oxalate, from plant roots. Once secreted, these anions chelate external Al ions, thus protecting the secreting plant from Al toxicity. Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized, and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance. In this review, we outline the recent history of research into plant Al-tolerance mechanisms, with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots. In particular, we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion. We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.
Aluminum ; toxicity ; Anions ; Biological Transport ; drug effects ; Citric Acid ; metabolism ; Malates ; metabolism ; Oxalic Acid ; metabolism ; Plant Roots ; drug effects ; metabolism ; Signal Transduction ; physiology

To explore the correlation between chemical compositions (organic acids, small molecule sugars, protein and others) of traditional Chinese medicine extracts and the wall stickiness in spray drying. In this study, 55 types of most common used Chinese herbs were selected to determine the content of 7 chemical components such as citric acid and fructose from plant extraction. The status of wall stickiness was observed during the drying process. The principle component analysis (PCA-X), hierarchical clustering analysis(HCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were then used to evaluate the correlation between each chemical compositions and wall stickiness, so as to look for the essential chemical compositions associated with the wall stickiness. All of the above 3 statistical analysis methods showed significant results in distinguishing the two groups (sticky or non-sticky). PCA-X score chart and HCA clustering scatter plot suggested that the small molecular substance was the main factor causing wall stickiness, which was then proved by the reality where some of the traditional herb extracts were in non-sticky state after drying but in sticky state after alcohol precipitation. OPLS-DA results revealed that L-malic acid, citric acid, fructose and glucose were the difference factors for the wall stickiness of the extracts. Under small molecular components, L-malic acid, citric acid, fructose and glucose were the crucial factors that directly led to the hot melt sticky wall of the herbal extracts, and macromolecular substances might ameliorate the function of wall stickiness.
Citric Acid ; Desiccation ; Discriminant Analysis ; Drugs, Chinese Herbal ; chemistry ; Fructose ; Glucose ; Least-Squares Analysis ; Malates ; Medicine, Chinese Traditional ; Plant Extracts ; chemistry ; Principal Component Analysis

The present study isolated 17 compounds from the tubers of Bletilla striata (Orchidaceae), using various chromatographic techniques. Their structures were identified based on their physical-chemical properties and spectroscopic analyses. Among them, two new 2-isobutylmalates, named bletimalates A (1) and B (2), together with other fifteen known compounds (3-17), were isolated and identified. Additionally, compounds 3, 4, and 8 were isolated from this plant for the first time.
Malates ; chemistry ; isolation & purification ; Molecular Structure ; Orchidaceae ; chemistry ; Plant Extracts ; chemistry ; isolation & purification ; Plant Tubers ; chemistry

Ten glucosyloxybenzyl 2-isobutylmalates and one benzyl alcohol glycoside were isolated from the dry tuber of Pleione bulbocodioides, which is a specie of Orchidaceae family and its dry tuber is one of the main sources of traditional Chinese medicine "shanci-gu", by a combination of various column chromatographic methods, including ODS, macroporous adsorbent resin, Sepheadex LH-20, and preparative HPLC. Their structures were identified on the basis of chemical evidences and spectroscopic analysis asloroglossin (1), grammatophylloside A (2), cronupapine (3), (-)-(2R, 3S)-1-(4-β-D-glucopyranosyloxybenzyl)-4-methyl-2-isobutyltartrate (4), vandateroside II (5), grammatophylloside B (6), bis [4-(β-D-glucopyranosyloxy) -benzyl] (S) -2-isopropylmalate (7), gymnoside I (8), militarine (9), dactylorhin A (10), gastrodin (11). Compounds 1-7 were isolated from this genus for the firt time.
Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Glucosides ; chemistry ; isolation & purification ; Malates ; chemistry ; isolation & purification ; Molecular Structure ; Orchidaceae ; chemistry ; Spectrometry, Mass, Electrospray Ionization

To develop a genetic transformation method of Aureobasidium pullulans and T-DNA insertion for high-efficient screening of polymalic acid (PMA) producing strain. Agrobacterium tumefaciens-AGL1, containing the selection genes encoding hygromycin B phosphotase or phosphinothricin acetyltranferase, was used to transform Aureobasidium pullulans CCTCC M2012223 and transformants were confirmed by colony PCR method. Transferred DNA (T-DNA) insertional mutants were cultured in microwell plate, and screened for high-titer PMA producing strain according to the pH response model. DNA walking was used to detect the insertion sites in the mutant. Results show that the selection markers could stably generated in the transformants, and 80 to 120 transformants could be found per 10(7) single cells. A high-titer PMA mutant H27 was obtained, giving a good PMA production caused by the disruption of phosphoglycerate mutase, that increased by 24.5% compared with the control. Agrobacterium tumefaciens-mediated transformation and high-efficient screening method were successfully developed, which will be helpful for genetic transformation of Aureobasidium pullulans and its functional genes discovery.
Agrobacterium tumefaciens ; Ascomycota ; genetics ; metabolism ; DNA, Bacterial ; Malates ; metabolism ; Polymerase Chain Reaction ; Polymers ; metabolism ; Transformation, Genetic

Polymalic acid, known as a bioactive material, is completely biodegradable, and has far reaching application potential in medical field. Combined with our own findings, we summarized advances in polymalic acid metabolism, microbial fermentation synthesis, and application research in the medical field. Finally, prospect for further research was addressed.
Fermentation ; Industrial Microbiology ; Malates ; chemistry ; Polymers ; chemistry

Malic acid is widely used in food, and chemical industries. Through overexpressing pyruvate carboxylase and malate dehydrogenase in pdc1-deficient Saccharomyces cerevisiae, malic acid was successfully produced through the reductive TCA pathway. No malic acid was detected in wild type Saccharomyces cerevisiae, however, 45 mmol/L malic acid was produced in engineered strain, and the concentration of byproduct ethanol also reduced by 18%. The production of malic acid enhanced 6% by increasing the concentration of Ca2+. In addition, the final concentration reached 52.5 mmol/L malic acid by addition of biotin. The increasing is almost 16% higher than that of the original strain.
Citric Acid Cycle ; Fermentation ; Industrial Microbiology ; methods ; Malate Dehydrogenase ; genetics ; metabolism ; Malates ; metabolism ; Metabolic Engineering ; methods ; Metabolic Networks and Pathways ; Oxidation-Reduction ; Pyruvate Carboxylase ; genetics ; metabolism ; Saccharomyces cerevisiae ; genetics ; metabolism ; Signal Transduction

To explore the adaptive mechanisms of plateau zokor (Myospalax baileyi) to the enduring digging activity in the hypoxic environment and of plateau pika (Ochotona curzoniae) to the sprint running activity, the functional differences of malate-aspartate shuttle system (MA) in liver of plateau zokor and plateau pika were studied. The ratio of liver weight to body weight, the parameters of mitochondria in hepatocyte and the contents of lactic acid in serum were measured; the open reading frame of cytoplasmic malate dehydrogenase (MDH1), mitochondrial malate dehydrogenase (MDH2), and the partial sequence of aspartate glutamate carrier (AGC) and oxoglutarate malate carrier (OMC) genes were cloned and sequenced; MDH1, MDH2, AGC and OMC mRNA levels were determined by real-time PCR; the specific activities of MDH1 and MDH2 in liver of plateau zokor and plateau pika were measured using enzymatic methods. The results showed that, (1) the ratio of liver weight to body weight, the number and the specific surface of mitochondria in hepatocyte of plateau zokor were markedly higher than those of plateau pika (P < 0.01 or P < 0.05), but the content of lactic acid in serum of plateau pika was significantly higher than that of plateau zokor (P < 0.01); (2) MDH1 and MDH2 mRNA levels as well as their enzymatic activities in liver of plateau zokor were significantly higher than those of plateau pika (P < 0.01 or 0.05), AGC mRNA level of the zokor was significantly higher than that of the pika (P < 0.01), while no difference was found at OMC mRNA level between them (P > 0.05); (3) mRNA level and enzymatic activity of MDH1 was significantly lower than those of MDH2 in the pika liver (P < 0.01), MDH1 mRNA level of plateau zokor was markedly higher than that of MDH2 (P < 0.01), but the activities had no difference between MDH1 and MDH2 in liver of the zokor (P > 0.05). These results indicate that the plateau zokor obtains ATP in the enduring digging activity by enhancing the function of MA, while plateau pika gets glycogen for their sprint running activity by increasing the process of gluconeogenesis. As a result, plateau pika converts the lactic acid quickly produced in their skeletal muscle by anaerobic glycolysis and reduces dependence on the oxygen.
Adaptation, Physiological ; physiology ; Adenosine Triphosphate ; metabolism ; Altitude ; Animals ; Aspartic Acid ; metabolism ; Cloning, Molecular ; L-Lactate Dehydrogenase ; analysis ; metabolism ; Lactic Acid ; blood ; Lagomorpha ; classification ; physiology ; Liver ; anatomy & histology ; physiology ; Malate Dehydrogenase ; genetics ; metabolism ; Malates ; metabolism ; Membrane Transport Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism