Adipose Tissue Branched Chain Amino Acid (BCAA) Metabolism Modulates Circulating BCAA Levels*

OpenAIRE

Herman, Mark A.; She, Pengxiang; Peroni, Odile D.; Lynch, Christopher J.; Kahn, Barbara B.

2010-01-01

Whereas the role of adipose tissue in glucose and lipid homeostasis is widely recognized, its role in systemic protein and amino acid metabolism is less well-appreciated. In vitro and ex vivo experiments suggest that adipose tissue can metabolize substantial amounts of branched chain amino acids (BCAAs). However, the role of adipose tissue in regulating BCAA metabolism in vivo is controversial. Interest in the contribution of adipose tissue to BCAA metabolism has been renewed with recent obse...

Metabolism of amino acid amides in Pseudomonas putida ATCC 12633

NARCIS (Netherlands)

Hermes, H.F.M.; Croes, L.M.; Peeters, W.P.H.; Peters, P.J.H.; Dijkhuizen, L.

1993-01-01

The metabolism of the natural amino acid L-valine, the unnatural amino acids D-valine, and D-, L-phenylglycine (D-, L-PG), and the unnatural amino acid amides D-, L-phenylglycine amide (D, L-PG-NH2) and L-valine amide (L-Val-NH2) was studied in Pseudomonas putida ATCC 12633. The organism possessed

Decreased Consumption of Branched-Chain Amino Acids Improves Metabolic Health

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Luigi Fontana

2016-07-01

Full Text Available Protein-restricted (PR, high-carbohydrate diets improve metabolic health in rodents, yet the precise dietary components that are responsible for these effects have not been identified. Furthermore, the applicability of these studies to humans is unclear. Here, we demonstrate in a randomized controlled trial that a moderate PR diet also improves markers of metabolic health in humans. Intriguingly, we find that feeding mice a diet specifically reduced in branched-chain amino acids (BCAAs is sufficient to improve glucose tolerance and body composition equivalently to a PR diet via metabolically distinct pathways. Our results highlight a critical role for dietary quality at the level of amino acids in the maintenance of metabolic health and suggest that diets specifically reduced in BCAAs, or pharmacological interventions in this pathway, may offer a translatable way to achieve many of the metabolic benefits of a PR diet.

Mitochondrial thiol modification by a targeted electrophile inhibits metabolism in breast adenocarcinoma cells by inhibiting enzyme activity and protein levels

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M. Ryan Smith

2016-08-01

Full Text Available Many cancer cells follow an aberrant metabolic program to maintain energy for rapid cell proliferation. Metabolic reprogramming often involves the upregulation of glutaminolysis to generate reducing equivalents for the electron transport chain and amino acids for protein synthesis. Critical enzymes involved in metabolism possess a reactive thiolate group, which can be modified by certain oxidants. In the current study, we show that modification of mitochondrial protein thiols by a model compound, iodobutyl triphenylphosphonium (IBTP, decreased mitochondrial metabolism and ATP in MDA-MB 231 (MB231 breast adenocarcinoma cells up to 6 days after an initial 24 h treatment. Mitochondrial thiol modification also depressed oxygen consumption rates (OCR in a dose-dependent manner to a greater extent than a non-thiol modifying analog, suggesting that thiol reactivity is an important factor in the inhibition of cancer cell metabolism. In non-tumorigenic MCF-10A cells, IBTP also decreased OCR; however the extracellular acidification rate was significantly increased at all but the highest concentration (10 µM of IBTP indicating that thiol modification can have significantly different effects on bioenergetics in tumorigenic versus non-tumorigenic cells. ATP and other adenonucleotide levels were also decreased by thiol modification up to 6 days post-treatment, indicating a decreased overall energetic state in MB231 cells. Cellular proliferation of MB231 cells was also inhibited up to 6 days post-treatment with little change to cell viability. Targeted metabolomic analyses revealed that thiol modification caused depletion of both Krebs cycle and glutaminolysis intermediates. Further experiments revealed that the activity of the Krebs cycle enzyme, aconitase, was attenuated in response to thiol modification. Additionally, the inhibition of glutaminolysis corresponded to decreased glutaminase C (GAC protein levels, although other protein levels were

New insights into the metabolism of aspartate-family amino acids in plant seeds.

Science.gov (United States)

Wang, Wenyi; Xu, Mengyun; Wang, Guoping; Galili, Gad

2018-02-05

Aspartate-family amino acids. Aspartate (Asp)-family pathway, via several metabolic branches, leads to four key essential amino acids: Lys, Met, Thr, and Ile. Among these, Lys and Met have received the most attention, as they are the most limiting amino acid in cereals and legumes crops, respectively. The metabolic pathways of these four essential amino acids and their interactions with regulatory networks have been well characterized. Using this knowledge, extensive efforts have been devoted to augmenting the levels of these amino acids in various plant organs, especially seeds, which serve as the main source of human food and livestock feed. Seeds store a number of storage proteins, which are utilized as nutrient and energy resources. Storage proteins are composed of amino acids, to guarantee the continuation of plant progeny. Thus, understanding the seed metabolism, especially with respect to the accumulation of aspartate-derived amino acids Lys and Met, is a crucial factor for sustainable agriculture. In this review, we summarized the Asp-family pathway, with some new examples of accumulated Asp-family amino acids, particularly Lys and Met, in plant seeds. We also discuss the recent advances in understanding the roles of Asp-family amino acids during seed development.

Subcritical Water Hydrolysis of Peptides: Amino Acid Side-Chain Modifications

Science.gov (United States)

Powell, Thomas; Bowra, Steve; Cooper, Helen J.

2017-09-01

Previously we have shown that subcritical water may be used as an alternative to enzymatic digestion in the proteolysis of proteins for bottom-up proteomics. Subcritical water hydrolysis of proteins was shown to result in protein sequence coverages greater than or equal to that obtained following digestion with trypsin; however, the percentage of peptide spectral matches for the samples treated with trypsin were consistently greater than for those treated with subcritical water. This observation suggests that in addition to cleavage of the peptide bond, subcritical water treatment results in other hydrolysis products, possibly due to modifications of amino acid side chains. Here, a model peptide comprising all common amino acid residues (VQSIKCADFLHYMENPTWGR) and two further model peptides (VCFQYMDRGDR and VQSIKADFLHYENPTWGR) were treated with subcritical water with the aim of probing any induced amino acid side-chain modifications. The hydrolysis products were analyzed by direct infusion electrospray tandem mass spectrometry, either collision-induced dissociation or electron transfer dissociation, and liquid chromatography collision-induced dissociation tandem mass spectrometry. The results show preferential oxidation of cysteine to sulfinic and sulfonic acid, and oxidation of methionine. In the absence of cysteine and methionine, oxidation of tryptophan was observed. In addition, water loss from aspartic acid and C-terminal amidation were observed in harsher subcritical water conditions. [Figure not available: see fulltext.

Regulation of intestinal protein metabolism by amino acids.

Science.gov (United States)

Bertrand, Julien; Goichon, Alexis; Déchelotte, Pierre; Coëffier, Moïse

2013-09-01

Gut homeostasis plays a major role in health and may be regulated by quantitative and qualitative food intake. In the intestinal mucosa, an intense renewal of proteins occurs, at approximately 50% per day in humans. In some pathophysiological conditions, protein turnover is altered and may contribute to intestinal or systemic diseases. Amino acids are key effectors of gut protein turnover, both as constituents of proteins and as regulatory molecules limiting intestinal injury and maintaining intestinal functions. Many studies have focused on two amino acids: glutamine, known as the preferential substrate of rapidly dividing cells, and arginine, another conditionally essential amino acid. The effects of glutamine and arginine on protein synthesis appear to be model and condition dependent, as are the involved signaling pathways. The regulation of gut protein degradation by amino acids has been minimally documented until now. This review will examine recent data, helping to better understand how amino acids regulate intestinal protein metabolism, and will explore perspectives for future studies.

The Emerging Role of Branched-Chain Amino Acids in Insulin Resistance and Metabolism

OpenAIRE

Yoon, Mee-Sup

2016-01-01

Insulin is required for maintenance of glucose homeostasis. Despite the importance of insulin sensitivity to metabolic health, the mechanisms that induce insulin resistance remain unclear. Branched-chain amino acids (BCAAs) belong to the essential amino acids, which are both direct and indirect nutrient signals. Even though BCAAs have been reported to improve metabolic health, an increased BCAA plasma level is associated with a high risk of metabolic disorder and future insulin resistance, or...

Effects of Heterologous tRNA Modifications on the Production of Proteins Containing Noncanonical Amino Acids

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Ana Crnković

2018-02-01

Full Text Available Synthesis of proteins with noncanonical amino acids (ncAAs enables the creation of protein-based biomaterials with diverse new chemical properties that may be attractive for material science. Current methods for large-scale production of ncAA-containing proteins, frequently carried out in Escherichia coli, involve the use of orthogonal aminoacyl-tRNA synthetases (o-aaRSs and tRNAs (o-tRNAs. Although o-tRNAs are designed to be orthogonal to endogenous aaRSs, their orthogonality to the components of the E. coli metabolism remains largely unexplored. We systematically investigated how the E. coli tRNA modification machinery affects the efficiency and orthogonality of o-tRNASep used for production of proteins with the ncAA O-phosphoserine (Sep. The incorporation of Sep into a green fluorescent protein (GFP in 42 E. coli strains carrying deletions of single tRNA modification genes identified several genes that affect the o-tRNA activity. Deletion of cysteine desulfurase (iscS increased the yield of Sep-containing GFP more than eightfold, while overexpression of dimethylallyltransferase MiaA and pseudouridine synthase TruB improved the specificity of Sep incorporation. These results highlight the importance of tRNA modifications for the biosynthesis of proteins containing ncAAs, and provide a novel framework for optimization of o-tRNAs.

Creating diversity by site-selective peptide modification: a customizable unit affords amino acids with high optical purity.

Science.gov (United States)

Romero-Estudillo, Ivan; Boto, Alicia

2013-11-15

The development of peptide libraries by site-selective modification of a few parent peptides would save valuable time and materials in discovery processes, but still is a difficult synthetic challenge. Herein natural hydroxyproline is introduced as a "convertible" unit for the production of a variety of optically pure amino acids, including expensive N-alkyl amino acids, and to achieve the mild, efficient, and site-selective modification of peptides.

Dependence of the metabolic fecal amino acids on the amino acid content of the feed. 1

International Nuclear Information System (INIS)

Krawielitzki, K.; Schadereit, R.; Voelker, T.; Reichel, K.

1981-01-01

The amount of metabolic fecal amino acids (MFAA) in dependence on the amino acid intake was determined for graded maize rations in 15 N-labelled rats and the part of labelled endogenous amino acids in feces was calculated by the isotope dilution method. The excretion of amino acids and MFAA in feces are described as functions of the amino acid intake for 17 amino acids and calculated regressively. For all 17 amino acids investigated, there was a more or less steep increase of MFAA according to an increasing amino acid intake. In contrast to N-free feeding, the MFAA increase to the 2- to 4.5-fold value in feeding with pure maize (16.5% crude protein). The thesis of the constancy of the excretion of MFAA can consequently be no longer maintained. The true digestibility according to the conventional method is, on an average of all amino acids, 7.3 units below ascertained according to the 15 N method. The limiting amino acids lysine and threonine revealed the greatest difference. Tryptophane as first limiting amino acid could not be determined. The true digestibility of nearly all amino acids ascertained for maize by the isotope method is above 90%. (author)

Perturbations in amino acids and metabolic pathways in osteoarthritis patients determined by targeted metabolomics analysis.

Science.gov (United States)

Chen, Rui; Han, Su; Liu, Xuefeng; Wang, Kunpeng; Zhou, Yong; Yang, Chundong; Zhang, Xi

2018-05-15

Osteoarthritis (OA) is a degenerative synovial joint disease affecting people worldwide. However, the exact pathogenesis of OA remains unclear. Metabolomics analysis was performed to obtain insight into possible pathogenic mechanisms and diagnostic biomarkers of OA. Ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-TQ-MS), followed by multivariate statistical analysis, was used to determine the serum amino acid profiles of 32 OA patients and 35 healthy controls. Variable importance for project values and Student's t-test were used to determine the metabolic abnormalities in OA. Another 30 OA patients were used as independent samples to validate the alterations in amino acids. MetaboAnalyst was used to identify the key amino acid pathways and construct metabolic networks describing their relationships. A total of 25 amino acids and four biogenic amines were detected by UPLC-TQ-MS. Differences in amino acid profiles were found between the healthy controls and OA patients. Alanine, γ-aminobutyric acid and 4-hydroxy-l-proline were important biomarkers distinguishing OA patients from healthy controls. The metabolic pathways with the most significant effects were involved in metabolism of alanine, aspartate, glutamate, arginine and proline. The results of this study improve understanding of the amino acid metabolic abnormalities and pathogenic mechanisms of OA at the molecular level. The metabolic perturbations may be important for the diagnosis and prevention of OA. Copyright © 2018 Elsevier B.V. All rights reserved.

Covalent immobilization of glucose oxidase on amino MOFs via post-synthetic modification

NARCIS (Netherlands)

Tudisco, C.G.; Zolubas, G.; Seoane de la Cuesta, B.; Zafarani, H.; Kazemzad Asiabi, M.; Gascon Sabate, J.; Hagedoorn, P.L.; Rassaei, L.

2016-01-01

The post-synthetic modification (PSM) of two amino-MOFs with glucose oxidase is reported in this study. The multi-step approach preserved the MOFs' structure and allowed the production of enzyme-functionalized MOFs (MOFs@GOx), which retained the enzymatic activity and showed selective properties

Tetrazine-Containing Amino Acid for Peptide Modification and Live Cell Labeling.

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Zhongqiu Ni

Full Text Available A novel amino acid derivative 3-(4-(1, 2, 4, 5-tetrazine-3-yl phenyl-2-aminopropanoic acid was synthesized in this study. The compound possessed better water-solubility and was synthesized more easily compared with the well-known and commercially available 3-(p-benzylamino-1, 2, 4, 5-tetrazine. Tetrazine-containing amino acid showed excellent stability in biological media and might be used for cancer cell labeling. Moreover, the compound remained relatively stable in 50% TFA/DCM with little decomposition after prolonged exposure at room temperature. The compound could be utilized as phenylalanine or tyrosine analogue in peptide modification, and the tetrazine-containing peptide demonstrated more significant biological activity than that of the parent peptide. The combination of tetrazine group and amino acid offered broad development prospects of the bioorthogonal labeling and peptide synthesis.

Study of Stationary Phase Metabolism Via Isotopomer Analysis of Amino Acids from an Isolated Protein

Energy Technology Data Exchange (ETDEWEB)

Shaikh, AfshanS.; Tang, YinjieJ.; Mukhopadhyay, Aindrila; Martin, Hector Garcia; Gin, Jennifer; Benke, Peter; Keasling, Jay D.

2009-09-14

Microbial production of many commercially important secondary metabolites occurs during stationary phase, and methods to measure metabolic flux during this growth phase would be valuable. Metabolic flux analysis is often based on isotopomer information from proteinogenic amino acids. As such, flux analysis primarily reflects the metabolism pertinent to the growth phase during which most proteins are synthesized. To investigate central metabolism and amino acids synthesis activity during stationary phase, addition of fully 13C-labeled glucose followed by induction of green fluorescent protein (GFP) expression during stationary phase was used. Our results indicate that Escherichia coli was able to produce new proteins (i.e., GFP) in the stationary phase, and the amino acids in GFP were mostly from degraded proteins synthesized during the exponential growth phase. Among amino acid biosynthetic pathways, only those for serine, alanine, glutamate/glutamine, and aspartate/asparagine had significant activity during the stationary phase.

Metabolic fate of lactoferricin-based antimicrobial peptides: effect of truncation and incorporation of amino acid analogs on the in vitro metabolic stability.

Science.gov (United States)

Svenson, Johan; Vergote, Valentijn; Karstad, Rasmus; Burvenich, Christian; Svendsen, John S; De Spiegeleer, Bart

2010-03-01

A series of promising truncated antibacterial tripeptides derived from lactoferricin has been prepared, and their in vitro metabolic stability in the main metabolic compartments, plasma, liver, kidney, stomach, duodenum, and brain, has been investigated for the first time. The potential stabilizing effect of truncation, C-terminal capping, and introduction of the bulky synthetic amino acid biphenylalanine is also investigated. The drug-like peptides displayed large differences in half-lives in the different matrixes ranging from 4.2 min in stomach and duodenum to 355.9 min in liver. Kinetic analysis of the metabolites revealed that several different degrading enzymes simultaneously target the different peptide bonds and that the outcome of the tested strategies to increase the stability is clearly enzyme-specific. Some of the metabolic enzymes even prefer the synthetic modifications incorporated over the natural counterparts. Collectively, it is shown that the necessary antibacterial pharmacophore generates compounds that are not only potent antibacterial peptides, but excellent substrates for the main degrading enzymes. All the amide bonds are thus rapidly targeted by different enzymes despite the short peptidic sequences of the tested compounds. Hence, our results illustrate that several structural changes are needed before these compounds can be considered for oral administration. Strategies to overcome such metabolic challenges are discussed.

Branched chain amino acids requirements and metabolism in pigs

DEFF Research Database (Denmark)

Assadi Soumeh, Elham

2015-01-01

There is an interest to reduce the dietary crude protein (CP) level to promote the gut health of piglets, eliminate the environmental nitrogen load from intensive pig farming, and to reduce diet costs. This is possible by estimating individual amino acid (AA) requirements and by optimizing the diet...... according to the ideal protein profile that is compatible with the animal AA demand for normal body function. During the past decades, it has been tried to understand and characterize branched chain amino acids (BCAA) requirements, biological importance, and mode of actions. This is interesting for two...... of the last “-omics”, is a global analysis and interpretation of metabolome in specific health or nutritional status. Non-targeted metabolomics is used for screening the metabolic profile, and the metabolic signature could be used for hypothesis generation. The results of a non-targeted LC-MS metabolomics...

Volatile profiling reveals intracellular metabolic changes in Aspergillus parasiticus: veA regulates branched chain amino acid and ethanol metabolism

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Roze Ludmila V

2010-08-01

Full Text Available Abstract Background Filamentous fungi in the genus Aspergillus produce a variety of natural products, including aflatoxin, the most potent naturally occurring carcinogen known. Aflatoxin biosynthesis, one of the most highly characterized secondary metabolic pathways, offers a model system to study secondary metabolism in eukaryotes. To control or customize biosynthesis of natural products we must understand how secondary metabolism integrates into the overall cellular metabolic network. By applying a metabolomics approach we analyzed volatile compounds synthesized by Aspergillus parasiticus in an attempt to define the association of secondary metabolism with other metabolic and cellular processes. Results Volatile compounds were examined using solid phase microextraction - gas chromatography/mass spectrometry. In the wild type strain Aspergillus parasiticus SU-1, the largest group of volatiles included compounds derived from catabolism of branched chain amino acids (leucine, isoleucine, and valine; we also identified alcohols, esters, aldehydes, and lipid-derived volatiles. The number and quantity of the volatiles produced depended on media composition, time of incubation, and light-dark status. A block in aflatoxin biosynthesis or disruption of the global regulator veA affected the volatile profile. In addition to its multiple functions in secondary metabolism and development, VeA negatively regulated catabolism of branched chain amino acids and synthesis of ethanol at the transcriptional level thus playing a role in controlling carbon flow within the cell. Finally, we demonstrated that volatiles generated by a veA disruption mutant are part of the complex regulatory machinery that mediates the effects of VeA on asexual conidiation and sclerotia formation. Conclusions 1 Volatile profiling provides a rapid, effective, and powerful approach to identify changes in intracellular metabolic networks in filamentous fungi. 2 VeA coordinates the

Essential amino acid metabolism in infected/non-infected, poor, Guatemalan children

International Nuclear Information System (INIS)

Mazariegos, M.; De Vettorazzi, C.; Solomons, N.W.; Caballero, B.

1994-01-01

Traditional methods used to evaluate protein metabolism left unanswered some of the relevant questions in public health in developing countries, such as growth retardation in children. Particularly, in developing countries, infection (clinical and subclinical) and malnutrition are still relevant problems, and the most important scientific issues for the application of stable isotope tracer methods are related to the impact of infection, such as the oxidative disposal of essential amino acids in well-nourished and malnourished children. The objectives of the present proposal are: (1) To simplify, make less expensive, less time-consuming, and less invasive, methods in clinical research on amino acid metabolism using stable-isotope tracers in children; and (2) To assess the effects of infection (clinical or subclinical) on whole-body protein turnover in children with and without malnutrition. The objectives involve the engineering and assessment of a portable instrument to be used in evaluations of protein oxidation in the developing world. Methodological issues such as intra- and inter-subject variability, which are of great importance for the interpretation of amino acid metabolism and protein turnover, will also be considered. 18 refs, 2 figs

Essential amino acid metabolism in infected/non-infected, poor, Guatemalan children

Energy Technology Data Exchange (ETDEWEB)

Mazariegos, M; De Vettorazzi, C; Solomons, N W [Hospital de Ojos y Oidos ` ` Dr. Rodolfo Robles V.` ` , Guatemala City (Guatemala). Centre for Studies of Sensory Impairment, Aging and Metabolism (CeSSIAM); Caballero, B [Johns Hopkins Univ., Baltimore, MD (United States). Centre for Human Nutrition

1994-12-31

Traditional methods used to evaluate protein metabolism left unanswered some of the relevant questions in public health in developing countries, such as growth retardation in children. Particularly, in developing countries, infection (clinical and subclinical) and malnutrition are still relevant problems, and the most important scientific issues for the application of stable isotope tracer methods are related to the impact of infection, such as the oxidative disposal of essential amino acids in well-nourished and malnourished children. The objectives of the present proposal are: (1) To simplify, make less expensive, less time-consuming, and less invasive, methods in clinical research on amino acid metabolism using stable-isotope tracers in children; and (2) To assess the effects of infection (clinical or subclinical) on whole-body protein turnover in children with and without malnutrition. The objectives involve the engineering and assessment of a portable instrument to be used in evaluations of protein oxidation in the developing world. Methodological issues such as intra- and inter-subject variability, which are of great importance for the interpretation of amino acid metabolism and protein turnover, will also be considered. 18 refs, 2 figs.

Amino-functionalized surface modification of polyacrylonitrile hollow fiber-supported polydimethylsiloxane membranes

Energy Technology Data Exchange (ETDEWEB)

Hu, Leiqing; Cheng, Jun, E-mail: juncheng@zju.edu.cn; Li, Yannan; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

2017-08-15

Highlights: • Amino group was introduced to improve surface polarity of PDMS membrane. • The water contact angle of PDMS membrane decreased after the modification. • The concentration of N atom on surface of PDMS membrane reached up to ∼6%. • The density of PDMS membrane decreased while the swelling degree increased. • CO{sub 2} permeability increased while selectivity decreased after the modification. - Abstract: This study aimed to improve surface polarity of polydimethylsiloxane (PDMS) membranes and provide surface active sites which were easy to react with other chemicals. 3-Aminopropyltriethoxysilane (APTES) containing an amino group was introduced into a PDMS membrane by crosslinking to prepare polyacrylonitrile hollow fiber-supported PDMS membranes with an amino-functionalized surface. Fourier transform infrared and X-ray photoelectron spectroscopic analyses proved the existence of APTES and its amino group in the PDMS membrane. The concentration of N atoms on the PDMS membrane surface reached ∼6% when the mass ratio of APTES/PDMS oligomer in the PDMS coating solution was increased to 4/3. The water contact angle decreased from ∼114° to ∼87.5°, indicating the improved surface polarization of the PDMS membrane. The density and swelling degree of the PDMS membrane decreased and increased, respectively, with increasing APTES content in PDMS. This phenomenon increased CO{sub 2} permeability and decreased CO{sub 2}/H{sub 2} selectivity, CO{sub 2}/CH{sub 4} selectivity, and CO{sub 2}/N{sub 2} selectivity. When the mass ratio of APTES/PDMS oligomer was increased from 0 to 4/3, the CO{sub 2} permeation rate of the hollow fiber-supported PDMS membranes initially decreased from ∼2370 GPU to ∼860 GPU and then increased to ∼2000 GPU due to the change in coating solution viscosity.

Alteration of metabolomic markers of amino-acid metabolism in piglets with in-feed antibiotics.

Science.gov (United States)

Mu, Chunlong; Yang, Yuxiang; Yu, Kaifan; Yu, Miao; Zhang, Chuanjian; Su, Yong; Zhu, Weiyun

2017-04-01

In-feed antibiotics have been used to promote growth in piglets, but its impact on metabolomics profiles associated with host metabolism is largely unknown. In this study, to test the hypothesis that antibiotic treatment may affect metabolite composition both in the gut and host biofluids, metabolomics profiles were analyzed in antibiotic-treated piglets. Piglets were fed a corn-soy basal diet with or without in-feed antibiotics from postnatal day 7 to day 42. The serum biochemical parameters, metabolomics profiles of the serum, urine, and jejunal digesta, and indicators of microbial metabolism (short-chain fatty acids and biogenic amines) were analyzed. Compared to the control group, antibiotics treatment did not have significant effects on serum biochemical parameters except that it increased (P Antibiotics treatment increased the relative concentrations of metabolites involved in amino-acid metabolism in the serum, while decreased the relative concentrations of most amino acids in the jejunal content. Antibiotics reduced urinary 2-ketoisocaproate and hippurate. Furthermore, antibiotics decreased (P Antibiotics significantly affected the concentrations of biogenic amines, which are derived from microbial amino-acid metabolism. The three major amines, putrescine, cadaverine, and spermidine, were all increased (P antibiotics-treated piglets. These results identified the phenomena that in-feed antibiotics may have significant impact on the metabolomic markers of amino-acid metabolism in piglets.

Lifestyle modification in the management of the metabolic syndrome: achievements and challenges

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Marchesini G

2010-11-01

Full Text Available Riccardo Dalle Grave1, Simona Calugi1, Elena Centis2, Rebecca Marzocchi2, Marwan El Ghoch1, Giulio Marchesini21Department of Eating & Weight Disorder, Villa Garda Hospital, Garda (VR, Italy; 2Unit of Metabolic Diseases & Clinical Dietetics, Alma Mater Studiorum – University of Bologna, Bologna, ItalyAbstract: Lifestyle modification based on behavior therapy is the most important and effective strategy to manage the metabolic syndrome. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioral and cognitive strategies. The intervention may be delivered face-to-face or in groups, or in groups combined with individual sessions. The main challenge of treatment is helping patients maintain healthy behavior changes in the long term. In the last few years, several strategies have been evaluated to improve the long-term effect of lifestyle modification. Promising results have been achieved by combining lifestyle modification with pharmacotherapy, using meals replacement, setting higher physical activity goals, and long-term care. The key role of cognitive processes in the success/failure of weight loss and maintenance suggests that new cognitive procedures and strategies should be included in the traditional lifestyle modification interventions, in order to help patients build a mind-set favoring long-term lifestyle changes. These new strategies raise optimistic expectations for an effective treatment of metabolic syndrome with lifestyle modifications, provided public health programs to change the environment where patients live support them.Keywords: metabolic syndrome, obesity, lifestyle modification, cognitive behavior therapy

Hepatocyte heterogeneity in the metabolism of amino acids and ammonia

NARCIS (Netherlands)

Häussinger, D.; Lamers, W. H.; Moorman, A. F.

1992-01-01

With respect to hepatocyte heterogeneity in ammonia and amino acid metabolism, two different patterns of sublobular gene expression are distinguished: 'gradient-type' and 'strict- or compartment-type' zonation. An example for strict-type zonation is the reciprocal distribution of carbamoylphosphate

The Emerging Role of Branched-Chain Amino Acids in Insulin Resistance and Metabolism

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Mee-Sup Yoon

2016-07-01

Full Text Available Insulin is required for maintenance of glucose homeostasis. Despite the importance of insulin sensitivity to metabolic health, the mechanisms that induce insulin resistance remain unclear. Branched-chain amino acids (BCAAs belong to the essential amino acids, which are both direct and indirect nutrient signals. Even though BCAAs have been reported to improve metabolic health, an increased BCAA plasma level is associated with a high risk of metabolic disorder and future insulin resistance, or type 2 diabetes mellitus (T2DM. The activation of mammalian target of rapamycin complex 1 (mTORC1 by BCAAs has been suggested to cause insulin resistance. In addition, defective BCAA oxidative metabolism might occur in obesity, leading to a further accumulation of BCAAs and toxic intermediates. This review provides the current understanding of the mechanism of BCAA-induced mTORC1 activation, as well as the effect of mTOR activation on metabolic health in terms of insulin sensitivity. Furthermore, the effects of impaired BCAA metabolism will be discussed in detail.

Nickel deficiency disrupts metabolism of ureides, amino acids, and organic acids of young pecan foliage.

Science.gov (United States)

Bai, Cheng; Reilly, Charles C; Wood, Bruce W

2006-02-01

The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan.

Amino acid metabolic signaling influences Aedes aegypti midgut microbiome variability.

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Sarah M Short

2017-07-01

Full Text Available The mosquito midgut microbiota has been shown to influence vector competence for multiple human pathogens. The microbiota is highly variable in the field, and the sources of this variability are not well understood, which limits our ability to understand or predict its effects on pathogen transmission. In this work, we report significant variation in female adult midgut bacterial load between strains of A. aegypti which vary in their susceptibility to dengue virus. Composition of the midgut microbiome was similar overall between the strains, with 81-92% of reads coming from the same five bacterial families, though we did detect differences in the presence of some bacterial families including Flavobacteriaceae and Entobacteriaceae. We conducted transcriptomic analysis on the two mosquito strains that showed the greatest difference in bacterial load, and found that they differ in transcript abundance of many genes implicated in amino acid metabolism, in particular the branched chain amino acid degradation pathway. We then silenced this pathway by targeting multiple genes using RNA interference, which resulted in strain-specific bacterial proliferation, thereby eliminating the difference in midgut bacterial load between the strains. This suggests that the branched chain amino acid (BCAA degradation pathway controls midgut bacterial load, though the mechanism underlying this remains unclear. Overall, our results indicate that amino acid metabolism can act to influence the midgut microbiota. Moreover, they suggest that genetic or physiological variation in BCAA degradation pathway activity may in part explain midgut microbiota variation in the field.

Amino Acid Metabolism in Acute Renal Failure: Influence of Intravenous Essential L-Amino Acid Hyperalimentation Therapy

Science.gov (United States)

Abel, Ronald M.; Shih, Vivian E.; Abbott, William M.; Beck, Clyde H.; Fischer, Josef E.

1974-01-01

A solution of 8 essential I-amino acids and hypertonic dextrose was administered to 5 patients in acute postoperative renal failure in a program of hyperalimentation designed to decrease the patient's catabolic state and to accrue certain metabolic benefits. A sixth patient receiving intravenous glucose alone served as a control. The pretreatment plasma concentrations of amino acids in all 6 patients did not differ significantly from normal; following intravenous essential amino acids at a dose of approximately 12.6 gm/24 hours, no significant elevations out of the normal range of these substances occurred. Since urinary excretion rates did not dramatically increase, urinary loss was excluded as a possible cause for the failure of increase of plasma concentrations. The results suggest that the administration of an intravenous solution of 1-amino acids and hypertonic dextrose is associated with rapid clearance from the blood of these substances and, with a failure of increased urinary excretion, indirect evidence of amino acid utilization for protein synthesis has been obtained. Histidine supplementation in patients with acute renal failure is probably unnecessary based on the lack of significant decreases in histidine concentrations in these patients. PMID:4850497

SULPHUR-CONTAINING AMINO ACIDS METABOLISM IN EXPERIMENTAL HYPER- AND HYPOTHYROIDISM IN RATS.

Science.gov (United States)

Nechiporuk, V; Zaichko, N; Korda, М; Melnyk, A; Koloshko, O

2017-10-01

Hyper- and hypothyroidism are some of the most common endocrinopathies that cause many metabolic disorders including amino acids metabolism. However, a specific molecular mechanism of thyroid hormones influence on sulphur-containing amino acids metabolism has not been established. The aim of our research was to investigate experimentally the influence of thyroid gland functional state on the main enzymatic systems of sulphur-containing amino acids metabolism in liver and kidneys, the content of homocysteine, cysteine and H2S in blood. The rats were administered with L-thyroxine and mercazolil to simulate the states of hyper- and hypothyroidism, which were confirmed by the content of fT3, fT4 and TSH in the blood. In liver and kidneys of the animals with hypothyroidism we observed the decrease in the activity of enzymes of remethylation cycle of S-adenosylmethioninsyntase, S-adenosylhomocysteinhyhdrolase, betaine-homocysteine methyltransferase. Suppression of transsulfuration transformation of homocysteine to cysteine in hypothyroidism was mainly due to the inhibition of cystathionine synthase activity of cystathionine-β-synthase, wherein cystathionase activity of cystathionine-γ-lyase was not changed. In animals with hypothyroidism we also noticed the inhibition of cysteine desulfunation reactions: the activity of enzymes of cystathionine-β-synthase, cystathionine-γ-lyase and cysteine aminotransferase significantly decreased in liver and kidneys. Experimental hyperthyroidism was accompanied by increase in activity of remethylation cycle enzymes, increase in cystationine synthase activity of cystathionine-β-synthase in liver and activity of these enzymes in kidneys. The simulation of hyperthyroidism led to the decrease of homocysteine concentration, and of hypothyroidism - to the increase of homocysteine and cysteine concentrations and reduced H2S content in blood of the animals. Thus, the significant risk factors for the development of atherosclerosis

Comparison of bare and amino modified mesoporous silica@poly(ethyleneimine)s xerogel as indomethacin carrier: Superiority of amino modification.

Science.gov (United States)

Li, Jing; Xu, Lu; Wang, Hongyu; Yang, Baixue; Liu, Hongzhuo; Pan, Weisan; Li, Sanming

2016-02-01

The purpose of this study was to facilely develop amino modified mesoporous silica xerogel synthesized using biomimetic method (B-AMSX) and to investigate its potential ability to be a drug carrier for loading poorly water-soluble drug indomethacin (IMC). For comparison, mesoporous silica xerogel without amino modification (B-MSX) was also synthesized using the same method. The changes of characteristics before and after IMC loading were systemically studied using fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS) and nitrogen adsorption/desorption analysis. The results showed that B-MSX and B-AMSX were spherical nanoparticles with mesoporous structure. Compared with B-MSX, IMC loading capacity of B-AMSX was higher because more drug molecules can be loaded through stronger hydrogen bonding force. DSC and SAXS analysis confirmed the amorphous state of IMC after being loaded into B-MSX and B-AMSX. The in vitro drug release study revealed that B-MSX and B-AMSX improved IMC release significantly, and B-AMSX released IMC a little faster than B-MSX because of larger pore diameter of IMC-AMSX. B-MSX and B-AMSX degraded gradually in dissolution medium evidenced by color reaction and absorbance value, and B-AMSX degraded slower than B-MSX due to amino modification. In conclusion, B-AMSX with superiority of higher loading capacity and enhanced dissolution release can be considered to be a good candidate as drug carrier for IMC. Copyright © 2015 Elsevier B.V. All rights reserved.

Transcriptome and Proteome Expression Analysis of the Metabolism of Amino Acids by the Fungus Aspergillus oryzae in Fermented Soy Sauce

Directory of Open Access Journals (Sweden)

Guozhong Zhao

2015-01-01

Full Text Available Amino acids comprise the majority of the flavor compounds in soy sauce. A portion of these amino acids are formed from the biosynthesis and metabolism of the fungus Aspergillus oryzae; however, the metabolic pathways leading to the formation of these amino acids in A. oryzae remain largely unknown. We sequenced the transcriptomes of A. oryzae 100-8 and A. oryzae 3.042 under similar soy sauce fermentation conditions. 2D gel electrophoresis was also used to find some differences in protein expression. We found that many amino acid hydrolases (endopeptidases, aminopeptidases, and X-pro-dipeptidyl aminopeptidase were expressed at much higher levels (mostly greater than double in A. oryzae 100-8 than in A. oryzae 3.042. Our results indicated that glutamate dehydrogenase may activate the metabolism of amino acids. We also found that the expression levels of some genes changed simultaneously in the metabolic pathways of tyrosine and leucine and that these conserved genes may modulate the function of the metabolic pathway. Such variation in the metabolic pathways of amino acids is important as it can significantly alter the flavor of fermented soy sauce.

Transcriptome and Proteome Expression Analysis of the Metabolism of Amino Acids by the Fungus Aspergillus oryzae in Fermented Soy Sauce.

Science.gov (United States)

Zhao, Guozhong; Yao, Yunping; Wang, Chunling; Tian, Fengwei; Liu, Xiaoming; Hou, Lihua; Yang, Zhen; Zhao, Jianxin; Zhang, Hao; Cao, Xiaohong

2015-01-01

Amino acids comprise the majority of the flavor compounds in soy sauce. A portion of these amino acids are formed from the biosynthesis and metabolism of the fungus Aspergillus oryzae; however, the metabolic pathways leading to the formation of these amino acids in A. oryzae remain largely unknown. We sequenced the transcriptomes of A. oryzae 100-8 and A. oryzae 3.042 under similar soy sauce fermentation conditions. 2D gel electrophoresis was also used to find some differences in protein expression. We found that many amino acid hydrolases (endopeptidases, aminopeptidases, and X-pro-dipeptidyl aminopeptidase) were expressed at much higher levels (mostly greater than double) in A. oryzae 100-8 than in A. oryzae 3.042. Our results indicated that glutamate dehydrogenase may activate the metabolism of amino acids. We also found that the expression levels of some genes changed simultaneously in the metabolic pathways of tyrosine and leucine and that these conserved genes may modulate the function of the metabolic pathway. Such variation in the metabolic pathways of amino acids is important as it can significantly alter the flavor of fermented soy sauce.

Carbohydrate metabolism during prolonged exercise and recovery: interactions between pyruvate dehydrogenase, fatty acids, and amino acids

DEFF Research Database (Denmark)

Mourtzakis, Marina; Saltin, B.; Graham, T.

2006-01-01

During prolonged exercise, carbohydrate oxidation may result from decreased pyruvate production and increased fatty acid supply and ultimately lead to reduced pyruvate dehydrogenase (PDH) activity. Pyruvate also interacts with the amino acids alanine, glutamine, and glutamate, whereby the decline...... amino acid taken up during exercise and recovery. Alanine and glutamine were also associated...... with pyruvate metabolism, and they comprised 68% of total amino-acid release during exercise and recovery. Thus reduced pyruvate production was primarily associated with reduced carbohydrate oxidation, whereas the greatest production of pyruvate was related to glutamate, glutamine, and alanine metabolism...

Lifestyle modification in the management of the metabolic syndrome: achievements and challenges

OpenAIRE

Riccardo Dalle Grave; Simona Calugi; Elena Centis; et al

2010-01-01

Riccardo Dalle Grave1, Simona Calugi1, Elena Centis2, Rebecca Marzocchi2, Marwan El Ghoch1, Giulio Marchesini21Department of Eating & Weight Disorder, Villa Garda Hospital, Garda (VR), Italy; 2Unit of Metabolic Diseases & Clinical Dietetics, Alma Mater Studiorum – University of Bologna, Bologna, ItalyAbstract: Lifestyle modification based on behavior therapy is the most important and effective strategy to manage the metabolic syndrome. Modern lifestyle modification t...

Metabolic Diet App Suite for inborn errors of amino acid metabolism.

Science.gov (United States)

Ho, Gloria; Ueda, Keiko; Houben, Roderick F A; Joa, Jeff; Giezen, Alette; Cheng, Barbara; van Karnebeek, Clara D M

2016-03-01

An increasing number of rare inborn errors of metabolism (IEMs) are amenable to targeted metabolic nutrition therapy. Daily adherence is important to attain metabolic control and prevent organ damage. This is challenging however, given the lack of information of disorder specific nutrient content of foods, the limited availability and cost of specialty products as well as difficulties in reliable calculation and tracking of dietary intake and targets. To develop apps for all inborn errors of amino acid metabolism for which the mainstay of treatment is a medical diet, and obtain patient and family feedback throughout the process to incorporate this into subsequent versions. The Metabolic Diet App Suite was created with input from health care professionals as a free, user-friendly, online tool for both mobile devices and desktop computers (http://www.metabolicdietapp.org) for 15 different IEMs. General information is provided for each IEM with links to useful online resources. Nutrient information is based on the MetabolicPro™, a North American food database compiled by the Genetic Metabolic Dietitians International (GMDI) Technology committee. After user registration, a personalized dashboard and management plan including specific nutrient goals are created. Each Diet App has a user-friendly interface and the functions include: nutrient intake counts, adding your own foods and homemade recipes and, managing a daily food diary. Patient and family feedback was overall positive and specific suggestions were used to further improve the App Suite. The Metabolic Diet App Suite aids individuals affected by IEMs to track and plan their meals. Future research should evaluate its impact on patient adherence, metabolic control, quality of life and health-related outcomes. The Suite will be updated and expanded to Apps for other categories of IEMs. Finally, this Suite is a support tool only, and does not replace medical/metabolic nutrition professional advice. Copyright �

The why and how of amino acid analytics in cancer diagnostics and therapy.

Science.gov (United States)

Manig, Friederike; Kuhne, Konstantin; von Neubeck, Cläre; Schwarzenbolz, Uwe; Yu, Zhanru; Kessler, Benedikt M; Pietzsch, Jens; Kunz-Schughart, Leoni A

2017-01-20

Pathological alterations in cell functions are frequently accompanied by metabolic reprogramming including modifications in amino acid metabolism. Amino acid detection is thus integral to the diagnosis of many hereditary metabolic diseases. The development of malignant diseases as metabolic disorders comes along with a complex dysregulation of genetic and epigenetic factors affecting metabolic enzymes. Cancer cells might transiently or permanently become auxotrophic for non-essential or semi-essential amino acids such as asparagine or arginine. Also, transformed cells are often more susceptible to local shortage of essential amino acids such as methionine than normal tissues. This offers new points of attacking unique metabolic features in cancer cells. To better understand these processes, highly sensitive methods for amino acid detection and quantification are required. Our review summarizes the main methodologies for amino acid detection with a particular focus on applications in biomedicine and cancer, provides a historical overview of the methodological pre-requisites in amino acid analytics. We compare classical and modern approaches such as the combination of gas chromatography and liquid chromatography with mass spectrometry (GC-MS/LC-MS). The latter is increasingly applied in clinical routine. We therefore illustrate an LC-MS workflow for analyzing arginine and methionine as well as their precursors and analogs in biological material. Pitfalls during protocol development are discussed, but LC-MS emerges as a reliable and sensitive tool for the detection of amino acids in biological matrices. Quantification is challenging, but of particular interest in cancer research as targeting arginine and methionine turnover in cancer cells represent novel treatment strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

Metabolic regulation of manganese superoxide dismutase expression via essential amino acid deprivation.

Science.gov (United States)

Aiken, Kimberly J; Bickford, Justin S; Kilberg, Michael S; Nick, Harry S

2008-04-18

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging.

Association of Branched and Aromatic Amino Acids Levels with Metabolic Syndrome and Impaired Fasting Glucose in Hypertensive Patients

OpenAIRE

Weng, Liming; Quinlivan, Eoin; Gong, Yan; Beitelshees, Amber L.; Shahin, Mohamed H.; Turner, Stephen T.; Chapman, Arlene B.; Gums, John G.; Johnson, Julie A.; Frye, Reginald F.; Garrett, Timothy J.; Cooper-DeHoff, Rhonda M.

2015-01-01

Background: The three branched amino acids (valine, leucine, and isoleucine) and two aromatic amino acids (tyrosine and phenylalanine) have been associated with many adverse metabolic pathways, including diabetes. However, these associations have been identified primarily in otherwise healthy Caucasian populations. We aimed to investigate the association of this five-amino-acid signature with metabolic syndrome and impaired fasting glucose (IFG) in a hypertensive cohort of Caucasian and Afric...

Urea application promotes amino acid metabolism and membrane lipid peroxidation in Azolla.

Science.gov (United States)

Chen, Jiana; Huang, Min; Cao, Fangbo; Pardha-Saradhi, P; Zou, Yingbin

2017-01-01

A pot experiment was conducted to evaluate the effect of urea on nitrogen metabolism and membrane lipid peroxidation in Azolla pinnata. Compared to controls, the application of urea to A. pinnata resulted in a 44% decrease in nitrogenase activity, no significant change in glutamine synthetase activity, 660% higher glutamic-pyruvic transaminase, 39% increase in free amino acid levels, 22% increase in malondialdehyde levels, 21% increase in Na+/K+- levels, 16% increase in Ca2+/Mg2+-ATPase levels, and 11% decrease in superoxide dismutase activity. In terms of H2O2 detoxifying enzymes, peroxidase activity did not change and catalase activity increased by 64% in urea-treated A. pinnata. These findings suggest that urea application promotes amino acid metabolism and membrane lipid peroxidation in A. pinnata.

Posttranscriptional RNA Modifications: playing metabolic games in a cell's chemical Legoland.

Science.gov (United States)

Helm, Mark; Alfonzo, Juan D

2014-02-20

Nature combines existing biochemical building blocks, at times with subtlety of purpose. RNA modifications are a prime example of this, where standard RNA nucleosides are decorated with chemical groups and building blocks that we recall from our basic biochemistry lectures. The result: a wealth of chemical diversity whose full biological relevance has remained elusive despite being public knowledge for some time. Here, we highlight several modifications that, because of their chemical intricacy, rely on seemingly unrelated pathways to provide cofactors for their synthesis. Besides their immediate role in affecting RNA function, modifications may act as sensors and transducers of information that connect a cell's metabolic state to its translational output, carefully orchestrating a delicate balance between metabolic rate and protein synthesis at a system's level. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nickel Deficiency Disrupts Metabolism of Ureides, Amino Acids, and Organic Acids of Young Pecan Foliage[OA

Science.gov (United States)

Bai, Cheng; Reilly, Charles C.; Wood, Bruce W.

2006-01-01

The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan. PMID:16415214

Combined metabolomic and correlation networks analyses reveal fumarase insufficiency altered amino acid metabolism.

Science.gov (United States)

Hou, Entai; Li, Xian; Liu, Zerong; Zhang, Fuchang; Tian, Zhongmin

2018-04-01

Fumarase catalyzes the interconversion of fumarate and l-malate in the tricarboxylic acid cycle. Fumarase insufficiencies were associated with increased levels of fumarate, decreased levels of malate and exacerbated salt-induced hypertension. To gain insights into the metabolism profiles induced by fumarase insufficiency and identify key regulatory metabolites, we applied a GC-MS based metabolomics platform coupled with a network approach to analyze fumarase insufficient human umbilical vein endothelial cells (HUVEC) and negative controls. A total of 24 altered metabolites involved in seven metabolic pathways were identified as significantly altered, and enriched for the biological module of amino acids metabolism. In addition, Pearson correlation network analysis revealed that fumaric acid, l-malic acid, l-aspartic acid, glycine and l-glutamic acid were hub metabolites according to Pagerank based on their three centrality indices. Alanine aminotransferase and glutamate dehydrogenase activities increased significantly in fumarase deficiency HUVEC. These results confirmed that fumarase insufficiency altered amino acid metabolism. The combination of metabolomics and network methods would provide another perspective on expounding the molecular mechanism at metabolomics level. Copyright © 2017 John Wiley & Sons, Ltd.

Urea application promotes amino acid metabolism and membrane lipid peroxidation in Azolla.

Directory of Open Access Journals (Sweden)

Jiana Chen

Full Text Available A pot experiment was conducted to evaluate the effect of urea on nitrogen metabolism and membrane lipid peroxidation in Azolla pinnata. Compared to controls, the application of urea to A. pinnata resulted in a 44% decrease in nitrogenase activity, no significant change in glutamine synthetase activity, 660% higher glutamic-pyruvic transaminase, 39% increase in free amino acid levels, 22% increase in malondialdehyde levels, 21% increase in Na+/K+- levels, 16% increase in Ca2+/Mg2+-ATPase levels, and 11% decrease in superoxide dismutase activity. In terms of H2O2 detoxifying enzymes, peroxidase activity did not change and catalase activity increased by 64% in urea-treated A. pinnata. These findings suggest that urea application promotes amino acid metabolism and membrane lipid peroxidation in A. pinnata.

Fluorescent D-amino-acids reveal bi-cellular cell wall modifications important for Bdellovibrio bacteriovorus predation.

Science.gov (United States)

Kuru, Erkin; Lambert, Carey; Rittichier, Jonathan; Till, Rob; Ducret, Adrien; Derouaux, Adeline; Gray, Joe; Biboy, Jacob; Vollmer, Waldemar; VanNieuwenhze, Michael; Brun, Yves V; Sockett, R Elizabeth

2017-12-01

Modification of essential bacterial peptidoglycan (PG)-containing cell walls can lead to antibiotic resistance; for example, β-lactam resistance by L,D-transpeptidase activities. Predatory Bdellovibrio bacteriovorus are naturally antibacterial and combat infections by traversing, modifying and finally destroying walls of Gram-negative prey bacteria, modifying their own PG as they grow inside prey. Historically, these multi-enzymatic processes on two similar PG walls have proved challenging to elucidate. Here, with a PG-labelling approach utilizing timed pulses of multiple fluorescent D-amino acids, we illuminate dynamic changes that predator and prey walls go through during the different phases of bacteria:bacteria invasion. We show formation of a reinforced circular port-hole in the prey wall, L,D-transpeptidase Bd -mediated D-amino acid modifications strengthening prey PG during Bdellovibrio invasion, and a zonal mode of predator elongation. This process is followed by unconventional, multi-point and synchronous septation of the intracellular Bdellovibrio, accommodating odd- and even-numbered progeny formation by non-binary division.

Metabolic Regulation of Manganese Superoxide Dismutase Expression via Essential Amino Acid Deprivation*

Science.gov (United States)

Aiken, Kimberly J.; Bickford, Justin S.; Kilberg, Michael S.; Nick, Harry S.

2008-01-01

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging. PMID:18187411

Metabolism of γ-hydroxyl-[1-14C] butyrate by rat brain: relationship to the Krebs cycle and metabolic compartmentation of amino acids

International Nuclear Information System (INIS)

Doherty, J.D.; Roth, R.H.

1978-01-01

Ninhydrin decarboxylation experiments were carried out on the labelled amino acids produced following intraventricular injection of either γ-hydroxy-[1- 14 C] butyric acid (GHB) or [1- 14 C] succinate. The loss of isotope (as 14 CO 2 ) was similar for both substances. The [1- 14 C] GHB metabolites lost 75% of the label and the [1- 14 C] succinate metabolites lost 68%. This observation gives support to the hypothesis that the rat brain has the enzymatic capacity to metabolize [1- 14 C] GHB to succinate and to amino acids that have the isotope in the carboxylic acid group adjacent to the α-amino group. These results also indicate that the label from [1- 14 C] GHB does not enter the Krebs cycle as acetate. The specific activity ratio of radio-labelled glutamine to glutamic acid was determined in order to evaluate which of the two major metabolic compartments prefentially metabolize GHB. It was found that for [1- 14 C] GHB the ratio was 4.20 +- 0.18 (S.E. for n = 7) and for [1- 14 C] succinate the ratio was 7.71 (average of two trials, 7.74 and 7.69). These results suggest that the compartment thought to be associated with glial cells and synaptosomal structures is largely responsible for the metabolism of GHB. Metabolism as it might relate to the neuropharmacological action of GHB is discussed. (author)

Lifestyle modification in the management of the metabolic syndrome: achievements and challenges.

Science.gov (United States)

Dalle Grave, Riccardo; Calugi, Simona; Centis, Elena; Marzocchi, Rebecca; El Ghoch, Marwan; Marchesini, Giulio

2010-11-02

Lifestyle modification based on behavior therapy is the most important and effective strategy to manage the metabolic syndrome. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioral and cognitive strategies. The intervention may be delivered face-to-face or in groups, or in groups combined with individual sessions. The main challenge of treatment is helping patients maintain healthy behavior changes in the long term. In the last few years, several strategies have been evaluated to improve the long-term effect of lifestyle modification. Promising results have been achieved by combining lifestyle modification with pharmacotherapy, using meals replacement, setting higher physical activity goals, and long-term care. The key role of cognitive processes in the success/failure of weight loss and maintenance suggests that new cognitive procedures and strategies should be included in the traditional lifestyle modification interventions, in order to help patients build a mind-set favoring long-term lifestyle changes. These new strategies raise optimistic expectations for an effective treatment of metabolic syndrome with lifestyle modifications, provided public health programs to change the environment where patients live support them.

Protein and amino acid metabolism in skeletal muscle

Energy Technology Data Exchange (ETDEWEB)

Wu, Guoyao.

1989-01-01

Isolated chick extensor digitorum communis (EDC) muscles and, in some experiments, rat skeletal muscles were used to study a number of aspects of protein and amino acid metabolism. (1) Chick EDC muscles synthesize and release large amounts of alanine and glutamine, which indirectly obtain their amino groups from branched-chain amino acids (BCAA). (2) Acetoacetate or DL-{beta}-hydroxybutyrate (4 mM) decrease (P < 0.01) alanine synthesis and BCAA transamination in EDC muscles from 24-h fasted chicks by decreasing (P < 0.01) intracellular concentrations of pyruvate due to inhibition of glycolysis. (3) Glutamine is extensively degraded in skeletal muscles from both chicks and rats, thus challenging the traditional view that glutamine oxidation is negligible in skeletal muscle. The cytosolic glutamine aminotransferases L and K in the rat and the mitochondrial phosphate-activated glutaminase in the chick play important roles in the conversion of glutamine to {alpha}-ketoglutarate for further oxidation. (4) Although methionine has been reported to be extensively transaminated in rat skeletal muscle preparations in the absence of other amino acids, transamination of methionine is absent or negligible in chick and rat skeletal muscles in the presence of physiological concentrations of amino acids. (5) Glutamine at 1.0-15 mM increases (P < 0.01) protein synthesis ({sup 3}H-phenylalanine incorporation), and at 10.0-15.0 mM decreases (P < 0.05) protein degradation ({sup 3}H-phenylalanine release from prelabelled protein in vivo) in EDC muscles from fed chicks as compared to muscles incubated in the absence of glutamine. (6) Acetoacetate or DL-{beta}-hydroxybutyrate (4 mM) has a small but significant inhibitory effect (P < 0.05) on the rate of protein synthesis, but has no effect (P > 0.05) on the rate of protein degradation in EDC muscles from fed chicks.

Adipose tissue branched chain amino acid (BCAA) metabolism modulates circulating BCAA levels.

Science.gov (United States)

Herman, Mark A; She, Pengxiang; Peroni, Odile D; Lynch, Christopher J; Kahn, Barbara B

2010-04-09

Whereas the role of adipose tissue in glucose and lipid homeostasis is widely recognized, its role in systemic protein and amino acid metabolism is less well-appreciated. In vitro and ex vivo experiments suggest that adipose tissue can metabolize substantial amounts of branched chain amino acids (BCAAs). However, the role of adipose tissue in regulating BCAA metabolism in vivo is controversial. Interest in the contribution of adipose tissue to BCAA metabolism has been renewed with recent observations demonstrating down-regulation of BCAA oxidation enzymes in adipose tissue in obese and insulin-resistant humans. Using gene set enrichment analysis, we observe alterations in adipose-tissue BCAA enzyme expression caused by adipose-selective genetic alterations in the GLUT4 glucose-transporter expression. We show that the rate of adipose tissue BCAA oxidation per mg of tissue from normal mice is higher than in skeletal muscle. In mice overexpressing GLUT4 specifically in adipose tissue, we observe coordinate down-regulation of BCAA metabolizing enzymes selectively in adipose tissue. This decreases BCAA oxidation rates in adipose tissue, but not in muscle, in association with increased circulating BCAA levels. To confirm the capacity of adipose tissue to modulate circulating BCAA levels in vivo, we demonstrate that transplantation of normal adipose tissue into mice that are globally defective in peripheral BCAA metabolism reduces circulating BCAA levels by 30% (fasting)-50% (fed state). These results demonstrate for the first time the capacity of adipose tissue to catabolize circulating BCAAs in vivo and that coordinate regulation of adipose-tissue BCAA enzymes may modulate circulating BCAA levels.

Metabolic flux rearrangement in the amino acid metabolism reduces ammonia stress in the α1-antitrypsin producing human AGE1.HN cell line.

Science.gov (United States)

Priesnitz, Christian; Niklas, Jens; Rose, Thomas; Sandig, Volker; Heinzle, Elmar

2012-03-01

This study focused on metabolic changes in the neuronal human cell line AGE1.HN upon increased ammonia stress. Batch cultivations of α(1)-antitrypsin (A1AT) producing AGE1.HN cells were carried out in media with initial ammonia concentrations ranging from 0mM to 5mM. Growth, A1AT production, metabolite dynamics and finally metabolic fluxes calculated by metabolite balancing were compared. Growth and A1AT production decreased with increasing ammonia concentration. The maximum A1AT concentration decreased from 0.63g/l to 0.51g/l. Central energy metabolism remained relatively unaffected exhibiting only slightly increased glycolytic flux at high initial ammonia concentration in the medium. However, the amino acid metabolism was significantly changed. Fluxes through transaminases involved in amino acid degradation were reduced concurrently with a reduced uptake of amino acids. On the other hand fluxes through transaminases working in the direction of amino acid synthesis, i.e., alanine and phosphoserine, were increased leading to increased storage of excess nitrogen in extracellular alanine and serine. Glutamate dehydrogenase flux was reversed increasingly fixing free ammonia with increasing ammonia concentration. Urea production additionally observed was associated with arginine uptake by the cells and did not increase at high ammonia stress. It was therefore not used as nitrogen sink to remove excess ammonia. The results indicate that the AGE1.HN cell line can adapt to ammonia concentrations usually present during the cultivation process to a large extent by changing metabolism but with slightly reduced A1AT production and growth. Copyright © 2012 Elsevier Inc. All rights reserved.

The effects of added sulphur amino acids, threonine and an ideal amino acid ratio on nitrogen metabolism in mature, overweight dogs.

Science.gov (United States)

Bohaty, Robin E; de Godoy, Maria R C; McLeod, Kyle R; Harmon, David L

2012-02-01

The objectives of this study were to investigate the effects of added essential amino acids in conjunction with a dietary lysine/MJ of 0.72 on nitrogen (N) metabolism in dogs. Treatments were; a control diet, a diet that provided an ideal amino acid profile (IAA), a diet with added total sulphur amino acids (TSAA), and a diet with added TSAA and threonine (TT). Diets were fed to eight overweight, mature, female hounds using a replicated 4 x 4 Latin Square design. Food intake was similar across treatments, however, food N intake was higher (p dogs formulated to provide a 0.72 g lysine/MJ ME ratio.

Branched-Chain Amino Acids and Insulin Metabolism: The Insulin Resistance Atherosclerosis Study (IRAS)

OpenAIRE

Lee, C. Christine; Watkins, Steve M.; Lorenzo, Carlos; Wagenknecht, Lynne E.; Il?yasova, Dora; Chen, Yii-Der I.; Haffner, Steven M.; Hanley, Anthony J.

2016-01-01

OBJECTIVE Recent studies using untargeted metabolomics approaches have suggested that plasma branched-chain amino acids (BCAAs) are associated with incident diabetes. However, little is known about the role of plasma BCAAs in metabolic abnormalities underlying diabetes and whether these relationships are consistent across ethnic populations at high risk for diabetes. We investigated the associations of BCAAs with insulin sensitivity (SI), acute insulin response (AIR), and metabolic clearance ...

Metabolism of branched-chain amino acids in leg muscles from tail-cast suspended intact and adrenalectomized rats

Science.gov (United States)

Jaspers, Stephen R.; Henriksen, Erik; Jacob, Stephan; Tischler, Marc E.

1989-01-01

The effects of muscle unloading, adrenalectomy, and cortisol treatment on the metabolism of branched-chain amino acids in the soleus and extensor digitorum longus of tail-cast suspended rats were investigated using C-14-labeled lucine, isoleucine, and valine in incubation studies. It was found that, compared to not suspended controls, the degradation of branched-chain amino acids in hind limb muscles was accelerated in tail-cast suspended rats. Adrenalectomy was found to abolish the aminotransferase flux and to diminish the dehydrogenase flux in the soleus. The data also suggest that cortisol treatment increases the rate of metabolism of branched-chain amino acids at the dehydrogenase step.

Control of amino acid transport coordinates metabolic reprogramming in T-cell malignancy.

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Grzes, K M; Swamy, M; Hukelmann, J L; Emslie, E; Sinclair, L V; Cantrell, D A

2017-12-01

This study explores the regulation and importance of System L amino acid transport in a murine model of T-cell acute lymphoblastic leukemia (T-ALL) caused by deletion of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). There has been a strong focus on glucose transport in leukemias but the present data show that primary T-ALL cells have increased transport of multiple nutrients. Specifically, increased leucine transport in T-ALL fuels mammalian target of rapamycin complex 1 (mTORC1) activity which then sustains expression of hypoxia inducible factor-1α (HIF1α) and c-Myc; drivers of glucose metabolism in T cells. A key finding is that PTEN deletion and phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P 3 ) accumulation is insufficient to initiate leucine uptake, mTORC1 activity, HIF1α or c-Myc expression in T cells and hence cannot drive T-ALL metabolic reprogramming. Instead, a key regulator for leucine transport in T-ALL is identified as NOTCH. Mass spectrometry based proteomics identifies SLC7A5 as the predominant amino acid transporter in primary PTEN -/- T-ALL cells. Importantly, expression of SLC7A5 is critical for the malignant transformation induced by PTEN deletion. These data reveal the importance of regulated amino acid transport for T-cell malignancies, highlighting how a single amino acid transporter can have a key role.

Multi-omics approach to study the growth efficiency and amino acid metabolism in Lactococcus lactis at various specific growth rates

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Arike Liisa

2011-02-01

Full Text Available Abstract Background Lactococcus lactis is recognised as a safe (GRAS microorganism and has hence gained interest in numerous biotechnological approaches. As it is fastidious for several amino acids, optimization of processes which involve this organism requires a thorough understanding of its metabolic regulations during multisubstrate growth. Results Using glucose limited continuous cultivations, specific growth rate dependent metabolism of L. lactis including utilization of amino acids was studied based on extracellular metabolome, global transcriptome and proteome analysis. A new growth medium was designed with reduced amino acid concentrations to increase precision of measurements of consumption of amino acids. Consumption patterns were calculated for all 20 amino acids and measured carbon balance showed good fit of the data at all growth rates studied. It was observed that metabolism of L. lactis became more efficient with rising specific growth rate in the range 0.10 - 0.60 h-1, indicated by 30% increase in biomass yield based on glucose consumption, 50% increase in efficiency of nitrogen use for biomass synthesis, and 40% reduction in energy spilling. The latter was realized by decrease in the overall product formation and higher efficiency of incorporation of amino acids into biomass. L. lactis global transcriptome and proteome profiles showed good correlation supporting the general idea of transcription level control of bacterial metabolism, but the data indicated that substrate transport systems together with lower part of glycolysis in L. lactis were presumably under allosteric control. Conclusions The current study demonstrates advantages of the usage of strictly controlled continuous cultivation methods combined with multi-omics approach for quantitative understanding of amino acid and energy metabolism of L. lactis which is a valuable new knowledge for development of balanced growth media, gene manipulations for desired product

Emerging Perspectives on Essential Amino Acid Metabolism in Obesity and the Insulin-Resistant State12

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Adams, Sean H.

2011-01-01

Dysregulation of insulin action is most often considered in the context of impaired glucose homeostasis, with the defining feature of diabetes mellitus being elevated blood glucose concentration. Complications arising from the hyperglycemia accompanying frank diabetes are well known and epidemiological studies point to higher risk toward development of metabolic disease in persons with impaired glucose tolerance. Although the central role of proper blood sugar control in maintaining metabolic health is well established, recent developments have begun to shed light on associations between compromised insulin action [obesity, prediabetes, and type 2 diabetes mellitus (T2DM)] and altered intermediary metabolism of fats and amino acids. For amino acids, changes in blood concentrations of select essential amino acids and their derivatives, in particular BCAA, sulfur amino acids, tyrosine, and phenylalanine, are apparent with obesity and insulin resistance, often before the onset of clinically diagnosed T2DM. This review provides an overview of these changes and places recent observations from metabolomics research into the context of historical reports in the areas of biochemistry and nutritional biology. Based on this synthesis, a model is proposed that links the FFA-rich environment of obesity/insulin resistance and T2DM with diminution of BCAA catabolic enzyme activity, changes in methionine oxidation and cysteine/cystine generation, and tissue redox balance (NADH/NAD+). PMID:22332087

Aging rather than stress strongly influences amino acid metabolisms in the brain and genital organs of female mice.

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Kodaira, Momoko; Nagasawa, Mao; Yamaguchi, Takeshi; Ikeda, Hiromi; Minaminaka, Kimie; Chowdhury, Vishwajit S; Yasuo, Shinobu; Furuse, Mitsuhiro

2017-03-01

Aging and stress affect quality of life, and proper nourishment is one of means of preventing this effect. Today, there is a focus on the amount of protein consumed by elderly people; however, changes in the amino acid metabolism of individuals have not been fully considered. In addition, the difference between average life span and healthy life years is larger in females than it is in males. To prolong the healthy life years of females, in the present study we evaluated the influence of stress and aging on metabolism and emotional behavior by comparing young and middle-aged female mice. After 28 consecutive days of immobilization stress, behavioral tests were conducted and tissue sampling was performed. The results showed that the body weight of middle-aged mice was severely lowered by stress, but emotional behaviors were hardly influenced by either aging or stress. Aging influenced changes in amino acid metabolism in the brain and increased various amino acid levels in the uterus and ovary. In conclusion, we found that aged mice were more susceptible to stress in terms of body-weight reduction, and that amino acid metabolisms in the brain and genital organs were largely influenced by aging rather than by stress. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Novel metabolic and physiological functions of branched chain amino acids: a review

Institute of Scientific and Technical Information of China (English)

Shihai Zhang; Xiangfang Zeng; Man Ren; Xiangbing Mao; Shiyan Qiao

2017-01-01

It is widely known that branched chain amino acids (BCAA) are not only elementary components for building muscle tissue but also participate in increasing protein synthesis in animals and humans.BCAA (isoleucine,leucine and valine) regulate many key signaling pathways,the most classic of which is the activation of the mTOR signaling pathway.This signaling pathway connects many diverse physiological and metabolic roles.Recent years have witnessed many striking developments in determining the novel functions of BCAA including:(1) Insufficient or excessive levels of BCAA in the diet enhances lipolysis.(2) BCAA,especially isoleucine,play a major role in enhancing glucose consumption and utilization by up-regulating intestinal and muscular glucose transporters.(3)Supplementation of leucine in the diet enhances meat quality in finishing pigs.(4) BCAA are beneficial for mammary health,milk quality and embryo growth.(5) BCAA enhance intestinal development,intestinal amino acid transportation and mucin production.(6) BCAA participate in up-regulating innate and adaptive immune responses.In addition,abnormally elevated BCAA levels in the blood (decreased BCAA catabolism) are a good biomarker for the early detection of obesity,diabetes and other metabolic diseases.This review will provide some insights into these novel metabolic and physiological functions of BCAA.

Novel metabolic and physiological functions of branched chain amino acids: a review.

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Zhang, Shihai; Zeng, Xiangfang; Ren, Man; Mao, Xiangbing; Qiao, Shiyan

2017-01-01

It is widely known that branched chain amino acids (BCAA) are not only elementary components for building muscle tissue but also participate in increasing protein synthesis in animals and humans. BCAA (isoleucine, leucine and valine) regulate many key signaling pathways, the most classic of which is the activation of the mTOR signaling pathway. This signaling pathway connects many diverse physiological and metabolic roles. Recent years have witnessed many striking developments in determining the novel functions of BCAA including: (1) Insufficient or excessive levels of BCAA in the diet enhances lipolysis. (2) BCAA, especially isoleucine, play a major role in enhancing glucose consumption and utilization by up-regulating intestinal and muscular glucose transporters. (3) Supplementation of leucine in the diet enhances meat quality in finishing pigs. (4) BCAA are beneficial for mammary health, milk quality and embryo growth. (5) BCAA enhance intestinal development, intestinal amino acid transportation and mucin production. (6) BCAA participate in up-regulating innate and adaptive immune responses. In addition, abnormally elevated BCAA levels in the blood (decreased BCAA catabolism) are a good biomarker for the early detection of obesity, diabetes and other metabolic diseases. This review will provide some insights into these novel metabolic and physiological functions of BCAA.

Effects of cadmium stress on growth and amino acid metabolism in two Compositae plants.

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Zhu, Guangxu; Xiao, Huayun; Guo, Qingjun; Zhang, Zhongyi; Zhao, Jingjing; Yang, Dan

2018-08-30

Cadmium, a high toxic heavy metal, is one of the most serious contaminants in soil and a potential threat to plant growth and human health. Amino acid metabolism has the central role in heavy metal stress resistance of plants. In this paper, a pot experiment was carried out to study the effects of different concentrations of cadmium (0, 3, 6, 12, 30 mg kg -1 ) on the growth, Cd accumulation and amino acid metabolism in two Compositae plants (Ageratum conyzoides L. and Crassocephalum crepidioides). The results showed that under cadmium stress, C. crepidioides accumulated more Cd in its shoot and was tolerant to Cd, whereas its low Cd-accumulating relative, A. conyzoides, suffered reduced growth. The Cd content in the aerial part of C. crepidioides exceeded the threshold of Cd-hyperaccumulator. Furthermore, the bioaccumulation factor (BCF) and biological transfer factor (BTF) values for Cd in C. crepidioides were > 1. Thus, C. crepidioides can be regarded as Cd-hyperaccumulator. The comparison between both studied plants indicated that Cd stress resulted in a differential but coordinated response of amino acid levels, which are playing a significant role in plant adaptation to Cd stress. Glu, Gln, Asp, Asn, Gaba, Val and Ala dominated the major amino acids. Higher Cd tolerance and Cd accumulation in C. crepidioides was associated with greater accumulation of free amino acids, especially for Gln and Asn, in C. crepidioides than in A. conyzoides. Copyright © 2018 Elsevier Inc. All rights reserved.

Dynamics of human whole body amino acid metabolism

International Nuclear Information System (INIS)

Young, V.R.

1981-01-01

The mechanism of regulation of the nitrogen metabolism in humans under various nutritional and physiological states was examined using stable isotopes. In the simultaneous continuous infusion of 1- [ 13 ] - leucine and α- [ 15 N]- lysine, their fluxed decreased when individuals received lower protein intake. The rates of oxidation and incorporation into body proteins of leucine changed in parallel with the protein intake. Such effects of diet on whole body leucine kinetics were modified by the energy state and dietary energy level. The nitrogen balance was also improved by an excess level of dietary energy. When the intake of dietary protein was lowered below the maintenance level, the whole body flux and de novo synthesis of glycine were lowered, but alanine synthesis was clearly increased. The intravenous infusion of glucose at 4 mg/kg.min, which causes increase in excess blood sugar and plasma insulin, increased the alanine flux, but had no effect on the glycine flux. The rate of albumin synthesis, determined by giving 15 N-glycine orally every 3 hr, decreased with the lowered intake of dietary protein in young men, but not in elderly men. This explains why the serum albumin synthesis increases with the increase in the intake of dietary protein in young men, but not in elderly men. The rate of whole body protein synthesis in young men receiving the L-amino acid diets providing with the required intake of specific amino acid was much lower than that in the men receiving the diets providing with generous intake of specific amino acid. Thus the control mechanism to maintain the homeostasis of body nitrogen and amino acids is related in some unknown way to the nutritional requirement of the hosts. (Kaihara, S.)

Proliferation-dependent changes in amino acid transport and glucose metabolism in glioma cell lines

International Nuclear Information System (INIS)

Sasajima, Toshio; Miyagawa, Tadashi; Oku, Takamitsu; Gelovani, Juri G.; Finn, Ronald; Blasberg, Ronald

2004-01-01

Amino acid imaging is increasingly being used for assessment of brain tumor malignancy, extent of disease, and prognosis. This study explores the relationship between proliferative activity, amino acid transport, and glucose metabolism in three glioma cell lines (U87, Hs683, C6) at different phases of growth in culture. Growth phase was characterized by direct cell counting, proliferation index determined by flow cytometry, and [ 3 H]thymidine (TdR) accumulation, and was compared with the uptake of two non-metabolized amino acids ([ 14 C]aminocyclopentane carboxylic acid (ACPC) and [ 14 C]aminoisobutyric acid (AIB)), and [ 18 F]fluorodeoxyglucose (FDG). Highly significant relationships between cell number (density), proliferation index, and TdR accumulation rate were observed in all cell lines (r>0.99). Influx (K 1 ) of both ACPC and AIB was directly related to cell density, and inversely related to the proliferation index and TdR accumulation in all cell lines. The volume of distribution (V d ) for ACPC and AIB was lowest during rapid growth and highest during the near-plateau growth phase in all cell lines. FDG accumulation in Hs683 and C6 cells was unaffected by proliferation rate, growth phase, and cell density, whereas FDG accumulation was correlated with TdR accumulation, growth phase, and cell density in U87 cells. This study demonstrates that proliferation rate and glucose metabolism are not necessarily co-related in all glioma cell lines. The values of K 1 and V d for ACPC and AIB under different growth conditions suggest that these tumor cell lines can up-regulate amino acid transporters in their cell membranes when their growth conditions become adverse and less than optimal. (orig.)

Multiple stable isotope tracer technique for studying the metabolic kinetics of amino acids in hepatic failure

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Zongqin, Xia; Tengchang, Dai; Jianhua, Zhang; Yaer, Hu; Bingyao, Yu; Xingrong, Xu; Guanlu, Huang; Gengrong, Shen; Yaqiu, Zhou; Hong, Yu

1987-08-01

In order to study the mechanism of the imbalance of amino acid metabolism during hepatic failure, a stable isotope tracer method for observing simultaneously the metabolic kinetics of several amino acids has been established. /sup 15/N-L-Ala, (2,3-D/sub 3/)-Leu and (2,3-D/sub 3/)-Phe were chosen as nonessential, branched chain and aromatic amino acids. A single iv injection of 40 mg N-Ala, 20 mg deuterated Leu and 20 mg deuterated Phe was given to each human subject. Blood samples were taken just before and at different times (up to 60 min) after the injection. Total free amino acids were isolated from the plasma with a small dowex 50 x 8 column and converted to trifluoroacetyl derivatives. Their abundances were then analyzed with a GC-MS system and typical double exponential time course curves were found for all the three labelled amino acids. A two-pool model was designed and applied for compartmental analysis. Significant changes were found in the kinetic parameters of Phe and Leu in patients with fulminant hepatitis or heptic cirrhosis. The half-lives of both Phe pools were longer and the pool sizes were larger than normal subjects, while the half-lives and pool sizes of Leu changes in the opposite direction. No marked change was found in Ala. The significance of intracellular imbalance of Phe and Leu metabolism was discussed. It is evident that the combination of GCMS technique and multiple-tracers labelled with stable isotopes is of great potential for similar purposes.

Essential amino-acid metabolism in infected/non-infected, poor, Guatemalan children

International Nuclear Information System (INIS)

Mazariegos, M.; Solomons, N.W.; Vettorazzi, C.; Caballero, B.

1996-01-01

As mentioned above, it was our intention to develop and test a simplified version of the protocol to assess amino acid metabolism in children. With the combined efforts of a team of experts in the field, a generic protocol was developed as a mandate of the first CRP held at Boston in the fall of 1993. During the beginning of 1994, the final version of such a protocol was released to all the participants of the CRP meeting and arrangements were made in order to apply it and assess its usefulness in the field setting. Therefore, we have shifted our activities to apply, assess and adapt the generic protocol. We are now testing the protocol in the field to establish the variability parameters in both between and within individuals. After testing and refining the protocol, with the help of other groups in developed countries, by validation and/or comparative studies, we would be in a better position to recommend it as a tool to study amino acid metabolism in children in developing countries, whether to describe some specific profiles or to evaluate nutrition interventions. 1 fig., 3 tabs

Amino Acids Are an Ineffective Fertilizer for Dunaliella spp. Growth

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Colin A. Murphree

2017-05-01

Full Text Available Autotrophic microalgae are a promising bioproducts platform. However, the fundamental requirements these organisms have for nitrogen fertilizer severely limit the impact and scale of their cultivation. As an alternative to inorganic fertilizers, we investigated the possibility of using amino acids from deconstructed biomass as a nitrogen source in the genus Dunaliella. We found that only four amino acids (glutamine, histidine, cysteine, and tryptophan rescue Dunaliella spp. growth in nitrogen depleted media, and that supplementation of these amino acids altered the metabolic profile of Dunaliella cells. Our investigations revealed that histidine is transported across the cell membrane, and that glutamine and cysteine are not transported. Rather, glutamine, cysteine, and tryptophan are degraded in solution by a set of oxidative chemical reactions, releasing ammonium that in turn supports growth. Utilization of biomass-derived amino acids is therefore not a suitable option unless additional amino acid nitrogen uptake is enabled through genetic modifications of these algae.

Associations among circulating branched-chain amino acids and tyrosine with muscle volume and glucose metabolism in individuals without diabetes

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Honda, Tatsuro

2016-01-01

Background and Aims: Amino acid metabolites including branched chain amino acids (BCAA) and tyrosine (Tyr) affect glucose metabolism. The effects of BCAA on insulin resistance in patients with diabetes seem to conflict with mechanisms determined in animal models and cultured cells. We investigated the physiological effects of BCAA and Tyr on glucose metabolism among healthy community dwellers to clarify the controversy surrounding the effects of BCAA. Participant and methods: We investigated ...

Defects in muscle branched-chain amino acid oxidation contribute to impaired lipid metabolism.

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Lerin, Carles; Goldfine, Allison B; Boes, Tanner; Liu, Manway; Kasif, Simon; Dreyfuss, Jonathan M; De Sousa-Coelho, Ana Luisa; Daher, Grace; Manoli, Irini; Sysol, Justin R; Isganaitis, Elvira; Jessen, Niels; Goodyear, Laurie J; Beebe, Kirk; Gall, Walt; Venditti, Charles P; Patti, Mary-Elizabeth

2016-10-01

Plasma levels of branched-chain amino acids (BCAA) are consistently elevated in obesity and type 2 diabetes (T2D) and can also prospectively predict T2D. However, the role of BCAA in the pathogenesis of insulin resistance and T2D remains unclear. To identify pathways related to insulin resistance, we performed comprehensive gene expression and metabolomics analyses in skeletal muscle from 41 humans with normal glucose tolerance and 11 with T2D across a range of insulin sensitivity (SI, 0.49 to 14.28). We studied both cultured cells and mice heterozygous for the BCAA enzyme methylmalonyl-CoA mutase (Mut) and assessed the effects of altered BCAA flux on lipid and glucose homeostasis. Our data demonstrate perturbed BCAA metabolism and fatty acid oxidation in muscle from insulin resistant humans. Experimental alterations in BCAA flux in cultured cells similarly modulate fatty acid oxidation. Mut heterozygosity in mice alters muscle lipid metabolism in vivo, resulting in increased muscle triglyceride accumulation, increased plasma glucose, hyperinsulinemia, and increased body weight after high-fat feeding. Our data indicate that impaired muscle BCAA catabolism may contribute to the development of insulin resistance by perturbing both amino acid and fatty acid metabolism and suggest that targeting BCAA metabolism may hold promise for prevention or treatment of T2D.

Amino Acid Metabolism and Transport Mechanisms as Potential Antifungal Targets

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Matthew W. McCarthy

2018-03-01

Full Text Available Discovering new drugs for treatment of invasive fungal infections is an enduring challenge. There are only three major classes of antifungal agents, and no new class has been introduced into clinical practice in more than a decade. However, recent advances in our understanding of the fungal life cycle, functional genomics, proteomics, and gene mapping have enabled the identification of new drug targets to treat these potentially deadly infections. In this paper, we examine amino acid transport mechanisms and metabolism as potential drug targets to treat invasive fungal infections, including pathogenic yeasts, such as species of Candida and Cryptococcus, as well as molds, such as Aspergillus fumigatus. We also explore the mechanisms by which amino acids may be exploited to identify novel drug targets and review potential hurdles to bringing this approach into clinical practice.

The Nitrogen Moieties of Dietary Nonessential Amino Acids Are Distinctively Metabolized in the Gut and Distributed to the Circulation in Rats.

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Nakamura, Hidehiro; Kawamata, Yasuko; Kuwahara, Tomomi; Sakai, Ryosei

2017-08-01

Background: Although previous growth studies in rodents have indicated the importance of dietary nonessential amino acids (NEAAs) as nitrogen sources, individual NEAAs have different growth-promoting activities. This phenomenon might be attributable to differences in the nitrogen metabolism of individual NEAAs. Objective: The aim of this study was to compare nitrogen metabolism across dietary NEAAs with the use of their 15 N isotopologues. Methods: Male Fischer rats (8 wk old) were given 1.0 g amino acid-defined diets containing either 15 N-labeled glutamate, glutamine (amino or amide), aspartate, alanine, proline, glycine, or serine hourly for 5-6 h. Then, steady-state amino acid concentrations and their 15 N enrichments in the gut and in portal and arterial plasma were measured by an amino acid analyzer and LC tandem mass spectrometry, respectively. Results: The intestinal 15 N distribution and portal-arterial balance of 15 N metabolites indicated that most dietary glutamate nitrogen (>90% of dietary input) was incorporated into various amino acids, including alanine, proline, and citrulline, in the gut. Dietary aspartate nitrogen, alanine nitrogen, and amino nitrogen of glutamine were distributed similarly to other amino acids both in the gut and in the circulation. In contrast, incorporation of the nitrogen moieties of dietary proline, serine, and glycine into other amino acids was less than that of other NEAAs, although interconversion between serine and glycine was very active. Cluster analysis of 15 N enrichment data also indicated that dietary glutamate nitrogen, aspartate nitrogen, alanine nitrogen, and the amino nitrogen of glutamine were distributed similarly to intestinal and circulating amino acids. Further, the analysis revealed close relations between intestinal and arterial 15 N enrichment for each amino acid. The steady-state 15 N enrichment of arterial amino acids indicated that substantial amounts of circulating amino acid nitrogen are derived

The Role of Microbial Amino Acid Metabolism in Host Metabolism

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Evelien P. J. G. Neis

2015-04-01

Full Text Available Disruptions in gut microbiota composition and function are increasingly implicated in the pathogenesis of obesity, insulin resistance, and type 2 diabetes mellitus. The functional output of the gut microbiota, including short-chain fatty acids and amino acids, are thought to be important modulators underlying the development of these disorders. Gut bacteria can alter the bioavailability of amino acids by utilization of several amino acids originating from both alimentary and endogenous proteins. In turn, gut bacteria also provide amino acids to the host. This could have significant implications in the context of insulin resistance and type 2 diabetes mellitus, conditions associated with elevated systemic concentrations of certain amino acids, in particular the aromatic and branched-chain amino acids. Moreover, several amino acids released by gut bacteria can serve as precursors for the synthesis of short-chain fatty acids, which also play a role in the development of obesity. In this review, we aim to compile the available evidence on the contribution of microbial amino acids to host amino acid homeostasis, and to assess the role of the gut microbiota as a determinant of amino acid and short-chain fatty acid perturbations in human obesity and type 2 diabetes mellitus.

Clostridium sticklandii, a specialist in amino acid degradation:revisiting its metabolism through its genome sequence

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Pelletier Eric

2010-10-01

Full Text Available Abstract Background Clostridium sticklandii belongs to a cluster of non-pathogenic proteolytic clostridia which utilize amino acids as carbon and energy sources. Isolated by T.C. Stadtman in 1954, it has been generally regarded as a "gold mine" for novel biochemical reactions and is used as a model organism for studying metabolic aspects such as the Stickland reaction, coenzyme-B12- and selenium-dependent reactions of amino acids. With the goal of revisiting its carbon, nitrogen, and energy metabolism, and comparing studies with other clostridia, its genome has been sequenced and analyzed. Results C. sticklandii is one of the best biochemically studied proteolytic clostridial species. Useful additional information has been obtained from the sequencing and annotation of its genome, which is presented in this paper. Besides, experimental procedures reveal that C. sticklandii degrades amino acids in a preferential and sequential way. The organism prefers threonine, arginine, serine, cysteine, proline, and glycine, whereas glutamate, aspartate and alanine are excreted. Energy conservation is primarily obtained by substrate-level phosphorylation in fermentative pathways. The reactions catalyzed by different ferredoxin oxidoreductases and the exergonic NADH-dependent reduction of crotonyl-CoA point to a possible chemiosmotic energy conservation via the Rnf complex. C. sticklandii possesses both the F-type and V-type ATPases. The discovery of an as yet unrecognized selenoprotein in the D-proline reductase operon suggests a more detailed mechanism for NADH-dependent D-proline reduction. A rather unusual metabolic feature is the presence of genes for all the enzymes involved in two different CO2-fixation pathways: C. sticklandii harbours both the glycine synthase/glycine reductase and the Wood-Ljungdahl pathways. This unusual pathway combination has retrospectively been observed in only four other sequenced microorganisms. Conclusions Analysis of the C

Glucose and amino acid metabolism in rat brain during sustained hypoglycemia

International Nuclear Information System (INIS)

Wong, K.L.; Tyce, G.M.

1983-01-01

The metabolism of glucose in brains during sustained hypoglycemia was studied. [U- 14 C]Glucose (20 microCi) was injected into control rats, and into rats at 2.5 hr after a bolus injection of 2 units of insulin followed by a continuous infusion of 0.2 units/100 g rat/hr. This regimen of insulin injection was found to result in steady-state plasma glucose levels between 2.5 and 3.5 mumol per ml. In the brains of control rats carbon was transferred rapidly from glucose to glutamate, glutamine, gamma-aminobutyric acid and aspartate and this carbon was retained in the amino acids for at least 60 min. In the brains of hypoglycemic rats, the conversion of carbon from glucose to amino acids was increased in the first 15 min after injection. After 15 min, the specific activity of the amino acids decreased in insulin-treated rats but not in the controls. The concentrations of alanine, glutamate, and gamma-amino-butyric acid decreased, and the concentration of aspartate increased, in the brains of the hypoglycemic rats. The concentration of pyridoxal-5'-phosphate, a cofactor in many of the reactions whereby these amino acids are formed from tricarboxylic acid cycle intermediates, was less in the insulin-treated rats than in the controls. These data provide evidence that glutamate, glutamine, aspartate, and GABA can serve as energy sources in brain during insulin-induced hypoglycemia

Defects in muscle branched-chain amino acid oxidation contribute to impaired lipid metabolism

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Carles Lerin

2016-10-01

Full Text Available Objective: Plasma levels of branched-chain amino acids (BCAA are consistently elevated in obesity and type 2 diabetes (T2D and can also prospectively predict T2D. However, the role of BCAA in the pathogenesis of insulin resistance and T2D remains unclear. Methods: To identify pathways related to insulin resistance, we performed comprehensive gene expression and metabolomics analyses in skeletal muscle from 41 humans with normal glucose tolerance and 11 with T2D across a range of insulin sensitivity (SI, 0.49 to 14.28. We studied both cultured cells and mice heterozygous for the BCAA enzyme methylmalonyl-CoA mutase (Mut and assessed the effects of altered BCAA flux on lipid and glucose homeostasis. Results: Our data demonstrate perturbed BCAA metabolism and fatty acid oxidation in muscle from insulin resistant humans. Experimental alterations in BCAA flux in cultured cells similarly modulate fatty acid oxidation. Mut heterozygosity in mice alters muscle lipid metabolism in vivo, resulting in increased muscle triglyceride accumulation, increased plasma glucose, hyperinsulinemia, and increased body weight after high-fat feeding. Conclusions: Our data indicate that impaired muscle BCAA catabolism may contribute to the development of insulin resistance by perturbing both amino acid and fatty acid metabolism and suggest that targeting BCAA metabolism may hold promise for prevention or treatment of T2D. Keywords: Insulin sensitivity, BCAA, Fatty acid oxidation, TCA cycle

Branched-chain amino acid metabolism in rat muscle: abnormal regulation in acidosis

International Nuclear Information System (INIS)

May, R.C.; Hara, Y.; Kelly, R.A.; Block, K.P.; Buse, M.G.; Mitch, W.E.

1987-01-01

Branched-chain amino acid (BCAA) metabolism is frequently abnormal in pathological conditions accompanied by chronic metabolic acidosis. To study how metabolic acidosis affects BCAA metabolism in muscle, rats were gavage fed a 14% protein diet with or without 4 mmol NH 4 Cl x 100 g body wt -1 x day -1 . Epitrochlearis muscles were incubated with L-[1- 14 C]-valine and L-[1- 14 C]leucine, and rates of decarboxylation, net transamination, and incorporation into muscle protein were measured. Plasma and muscle BCAA levels were lower in acidotic rats. Rates of valine and leucine decarboxylation and net transamination were higher in muscles from acidotic rats; these differences were associated with a 79% increase in the total activity of branched-chain α-keto acid dehydrogenase and a 146% increase in the activated form of the enzyme. They conclude that acidosis affects the regulation of BCAA metabolism by enhancing flux through the transaminase and by directly stimulating oxidative catabolism through activation of branched-chain α-keto acid dehydrogenase

Branched-chain amino acid metabolism in rat muscle: abnormal regulation in acidosis

Energy Technology Data Exchange (ETDEWEB)

May, R.C.; Hara, Y.; Kelly, R.A.; Block, K.P.; Buse, M.G.; Mitch, W.E.

1987-06-01

Branched-chain amino acid (BCAA) metabolism is frequently abnormal in pathological conditions accompanied by chronic metabolic acidosis. To study how metabolic acidosis affects BCAA metabolism in muscle, rats were gavage fed a 14% protein diet with or without 4 mmol NH/sub 4/Cl x 100 g body wt/sup -1/ x day/sup -1/. Epitrochlearis muscles were incubated with L-(1-/sup 14/C)-valine and L-(1-/sup 14/C)leucine, and rates of decarboxylation, net transamination, and incorporation into muscle protein were measured. Plasma and muscle BCAA levels were lower in acidotic rats. Rates of valine and leucine decarboxylation and net transamination were higher in muscles from acidotic rats; these differences were associated with a 79% increase in the total activity of branched-chain ..cap alpha..-keto acid dehydrogenase and a 146% increase in the activated form of the enzyme. They conclude that acidosis affects the regulation of BCAA metabolism by enhancing flux through the transaminase and by directly stimulating oxidative catabolism through activation of branched-chain ..cap alpha..-keto acid dehydrogenase.

2-Oxoglutarate: linking TCA cycle function with amino acid, glucosinolate, flavonoid, alkaloid, and gibberellin biosynthesis.

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Araújo, Wagner L; Martins, Auxiliadora O; Fernie, Alisdair R; Tohge, Takayuki

2014-01-01

The tricarboxylic acid (TCA) cycle intermediate 2-oxoglutarate (2-OG) is used as an obligatory substrate in a range of oxidative reactions catalyzed by 2-OG-dependent dioxygenases. These enzymes are widespread in nature being involved in several important biochemical processes. We have recently demonstrated that tomato plants in which the TCA cycle enzyme 2-OG dehydrogenase (2-ODD) was antisense inhibited were characterized by early senescence and modified fruit ripening associated with differences in the levels of bioactive gibberellin (GA). Accordingly, there is now compelling evidence that the TCA cycle plays an important role in modulating the rate of flux from 2-OG to amino acid metabolism. Here we discuss recent advances in the biochemistry and molecular biology of 2-OG metabolism occurring in different biological systems indicating the importance of 2-OG and 2-OG dependent dioxygenases not only in glucosinolate, flavonoid and alkaloid metabolism but also in GA and amino acid metabolism. We additionally summarize recent findings regarding the impact of modification of 2-OG metabolism on biosynthetic pathways involving 2-ODDs.

Yearly growth and metabolic changes in earthen pond-cultured meagre Argyrosomus regius

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Luis Vargas-Chacoff

2014-06-01

Full Text Available Metabolic modifications associated with natural environmental conditions were assessed in the meagre Argyrosomus regius cultured in earthen ponds under natural photoperiod and temperature. Juvenile specimens (90-100 g initial weight were sampled (plasma, liver and muscle every two months for 18 months (between December 2004 and May 2006. Specimens showed seasonal variations in growth rate, with the highest values in spring and summer. Plasmatic, hepatic and muscular metabolite levels and hepatic and muscular metabolic enzymes also showed significant variations throughout the year. Enzymatic activity related to carbohydrate metabolism in the liver (HK, FBPase and G6PDH showed great modifications in summer, increasing glycogenogenic pathways, while amino acid metabolism (GDH and GOT activity was enhanced in spring and summer. However lipid-related (G3PDH activity metabolic enzymes did not show a clear seasonal pattern. In muscle, enzymatic activity related to amino acid, lipid and lactate metabolism (LDH-O activity, but not carbohydrate metabolism, showed seasonal changes in parallel with changes in growth rate. Thus A. regius specimens showed a trend to grow in summer months and mobilize their energy reserves in winter. Differences in the hepatic level were observed between the first and the second year of the study, suggesting the possible existence of metabolic changes related to specimen age or size. Our results indicate that growth and metabolic responses in A. regius are environmentally dependent and that this species is a very good candidate for diversification in aquaculture.

Maternal Diabetes Leads to Adaptation in Embryonic Amino Acid Metabolism during Early Pregnancy.

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Gürke, Jacqueline; Hirche, Frank; Thieme, René; Haucke, Elisa; Schindler, Maria; Stangl, Gabriele I; Fischer, Bernd; Navarrete Santos, Anne

2015-01-01

During pregnancy an adequate amino acid supply is essential for embryo development and fetal growth. We have studied amino acid composition and branched chain amino acid (BCAA) metabolism at day 6 p.c. in diabetic rabbits and blastocysts. In the plasma of diabetic rabbits the concentrations of 12 amino acids were altered in comparison to the controls. Notably, the concentrations of the BCAA leucine, isoleucine and valine were approximately three-fold higher in diabetic rabbits than in the control. In the cavity fluid of blastocysts from diabetic rabbits BCAA concentrations were twice as high as those from controls, indicating a close link between maternal diabetes and embryonic BCAA metabolism. The expression of BCAA oxidizing enzymes and BCAA transporter was analysed in maternal tissues and in blastocysts. The RNA amounts of three oxidizing enzymes, i.e. branched chain aminotransferase 2 (Bcat2), branched chain ketoacid dehydrogenase (Bckdha) and dehydrolipoyl dehydrogenase (Dld), were markedly increased in maternal adipose tissue and decreased in liver and skeletal muscle of diabetic rabbits than in those of controls. Blastocysts of diabetic rabbits revealed a higher Bcat2 mRNA and protein abundance in comparison to control blastocysts. The expression of BCAA transporter LAT1 and LAT2 were unaltered in endometrium of diabetic and healthy rabbits, whereas LAT2 transcripts were increased in blastocysts of diabetic rabbits. In correlation to high embryonic BCAA levels the phosphorylation amount of the nutrient sensor mammalian target of rapamycin (mTOR) was enhanced in blastocysts caused by maternal diabetes. These results demonstrate a direct impact of maternal diabetes on BCAA concentrations and degradation in mammalian blastocysts with influence on embryonic mTOR signalling.

Maternal Diabetes Leads to Adaptation in Embryonic Amino Acid Metabolism during Early Pregnancy.

Directory of Open Access Journals (Sweden)

Jacqueline Gürke

Full Text Available During pregnancy an adequate amino acid supply is essential for embryo development and fetal growth. We have studied amino acid composition and branched chain amino acid (BCAA metabolism at day 6 p.c. in diabetic rabbits and blastocysts. In the plasma of diabetic rabbits the concentrations of 12 amino acids were altered in comparison to the controls. Notably, the concentrations of the BCAA leucine, isoleucine and valine were approximately three-fold higher in diabetic rabbits than in the control. In the cavity fluid of blastocysts from diabetic rabbits BCAA concentrations were twice as high as those from controls, indicating a close link between maternal diabetes and embryonic BCAA metabolism. The expression of BCAA oxidizing enzymes and BCAA transporter was analysed in maternal tissues and in blastocysts. The RNA amounts of three oxidizing enzymes, i.e. branched chain aminotransferase 2 (Bcat2, branched chain ketoacid dehydrogenase (Bckdha and dehydrolipoyl dehydrogenase (Dld, were markedly increased in maternal adipose tissue and decreased in liver and skeletal muscle of diabetic rabbits than in those of controls. Blastocysts of diabetic rabbits revealed a higher Bcat2 mRNA and protein abundance in comparison to control blastocysts. The expression of BCAA transporter LAT1 and LAT2 were unaltered in endometrium of diabetic and healthy rabbits, whereas LAT2 transcripts were increased in blastocysts of diabetic rabbits. In correlation to high embryonic BCAA levels the phosphorylation amount of the nutrient sensor mammalian target of rapamycin (mTOR was enhanced in blastocysts caused by maternal diabetes. These results demonstrate a direct impact of maternal diabetes on BCAA concentrations and degradation in mammalian blastocysts with influence on embryonic mTOR signalling.

Radiation-induced reductive modifications of sulfur-containing amino acids within peptides and proteins.

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Chatgilialoglu, Chryssostomos; Ferreri, Carla; Torreggiani, Armida; Salzano, Anna Maria; Renzone, Giovanni; Scaloni, Andrea

2011-10-19

The complex scenario of radical stress reactions affecting peptides/proteins can be better elucidated through the design of biomimetic studies simulating the consequences of the different free radicals attacking amino acids. In this context, ionizing radiations allowed to examine the specific damages caused by H-atoms and electrons coupled with protons, thus establishing the molecular basis of reductive radical stress. This is an innovative concept that complements the well-known oxidative stress also in view of a complete understanding of the global consequences of radical species reactivities on living systems. This review summarizes the knowledge of the chemical changes present in sulfur-containing amino acids occurring in polypeptides under reductive radical conditions, in particular the transformation of Met and Cys residues into α-amino butyric acid and alanine, respectively. Reductive radical stress causing a desulfurization process, is therefore coupled with the formation of S-centered radicals, which in turn can diffuse apart and become responsible of the damage transfer from proteins to lipids. These reductive modifications assayed in different peptide/protein sequences constitute an integration of the molecular inventories that up to now take into account only oxidative transformations. They can be useful to achieve an integrated vision of the free radical reactivities in a multifunctional system and, overall, for wider applications in the redox proteomics field. Copyright © 2011 Elsevier B.V. All rights reserved.

Modification of nucleotide metabolism in relationship with differentiation and in response to irradiation in human tumour cells

International Nuclear Information System (INIS)

Wei, Shuang

1998-01-01

This research thesis reports the study of the metabolism of nucleotides in human tumour cells. The first part addresses the modifications of nucleotide (more specifically purine) metabolism in relationship with human melanoma cell proliferation and differentiation. The second part addresses the modifications of this metabolism in response to an irradiation in human colon tumour cells. For each part, the author proposes a bibliographic synthesis, and a presentation of studied cells and of methods used to grow cells, and respectively to proliferate and differentiate them or to irradiate them, and then discusses the obtained results [fr

Branched-Chain Amino Acid Levels Are Related with Surrogates of Disturbed Lipid Metabolism among Older Men

OpenAIRE

Urho M Kujala; Markku Peltonen; Merja K. Laine; Merja K. Laine; Jaakko Kaprio; Jaakko Kaprio; Jaakko Kaprio; Olli. J. Heinonen; Jouko Sundvall; Johan G. Eriksson; Johan G. Eriksson; Johan G. Eriksson; Antti Jula; Seppo Sarna; Heikki Kainulainen

2016-01-01

Aims/hypothesis Existing studies suggest that decreased branched-chain amino acid (BCAA) catabolism and thus elevated levels in blood are associated with metabolic disturbances. Based on such information we have developed a hypothesis how BCAA degradation mechanistically connects to tricarboxylic acid (TCA) cycle, intramyocellular lipid storage and oxidation thus allowing more efficient mitochondrial energy production from lipids as well as providing better metabolic health. We analyzed wheth...

High Temperature During Rice Grain Filling Enhances Aspartate Metabolism in Grains and Results in Accumulation of Aspartate-Family Amino Acids and Protein Components

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Cheng-gang LIANG

2013-09-01

Full Text Available Global warming causes the exacerbation of rice growing environment, which seriously affects rice growth and reproduction, and finally results in the decrease of rice yield and quality. We investigated the activities of aspartate metabolism enzymes in grains, and the contents of Aspartate-family amino acids and protein components to further understand the effects of high temperature (HT on rice nutritional quality during rice grain filling. Under HT, the average activities of aspartate aminotransferase (AAT and aspartokinase (AK in grains significantly increased, the amino acid contents of aspartate (Asp, lysine (Lys, threonine (Thr, methionine (Met and isoleucine (Ile and the protein contents of albumin, globulin, prolamin and glutelin also significantly increased. The results indicated that HT enhanced Asp metabolism during rice grain filling and the enhancement of Asp metabolism might play an important role in the increase of Asp-family amino acids and protein components in grains. In case of the partial appraisal of the change of Asp-family amino acids and protein components under HT, we introduced eight indicators (amino acid or protein content, ratio of amino acid or protein, amino acid or protein content per grain and amino acid or protein content per panicle to estimate the effects of HT. It is suggested that HT during rice grain filling was benefit for the accumulation of Asp-family amino acids and protein components. Combined with the improvement of Asp-family amino acid ratio in grains under HT, it is suggested that HT during grain filling may improve the rice nutritional quality. However, the yields of parts of Asp-family amino acids and protein components were decreased under HT during rice grain filling.

Novel metabolic and physiological functions of branched chain amino acids: a review

OpenAIRE

Zhang, Shihai; Zeng, Xiangfang; Ren, Man; Mao, Xiangbing; Qiao, Shiyan

2017-01-01

It is widely known that branched chain amino acids (BCAA) are not only elementary components for building muscle tissue but also participate in increasing protein synthesis in animals and humans. BCAA (isoleucine, leucine and valine) regulate many key signaling pathways, the most classic of which is the activation of the mTOR signaling pathway. This signaling pathway connects many diverse physiological and metabolic roles. Recent years have witnessed many striking developments in determining ...

A 48-Hour Vegan Diet Challenge in Healthy Women and Men Induces a BRANCH-Chain Amino Acid Related, Health Associated, Metabolic Signature.

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Draper, Colleen Fogarty; Vassallo, Irene; Di Cara, Alessandro; Milone, Cristiana; Comminetti, Ornella; Monnard, Irina; Godin, Jean-Philippe; Scherer, Max; Su, MingMing; Jia, Wei; Guiraud, Seu-Ping; Praplan, Fabienne; Guignard, Laurence; Ammon Zufferey, Corinne; Shevlyakova, Maya; Emami, Nashmil; Moco, Sofia; Beaumont, Maurice; Kaput, Jim; Martin, Francois-Pierre

2018-02-01

Research is limited on diet challenges to improve health. A short-term, vegan protein diet regimen nutritionally balanced in macronutrient composition compared to an omnivorous diet is hypothesized to improve metabolic measurements of blood sugar regulation, blood lipids, and amino acid metabolism. This randomized, cross-over, controlled vegan versus animal diet challenge is conducted on 21 (11 female,10 male) healthy participants. Fasting plasma is measured during a 3 d diet intervention for clinical biochemistry and metabonomics. Intervention diet plans meet individual caloric needs. Meals are provided and supervised. Diet compliance is monitored. The vegan diet lowers triglycerides, insulin and homeostatic model assessment (HOMA-IR), bile acids, elevated magnesium levels, and changed branched-chain amino acids (BCAAs) metabolism (p vegan versus omnivorous diets. Plasma amino acid and magnesium concentrations positively correlate with dietary amino acids. Polyunsaturated fatty acids and dietary fiber inversely correlate with insulin, HOMA-IR, and triglycerides. Nutritional biochemistries, BCAAs, insulin, and HOMA-IR are impacted by sexual dimorphism. A health-promoting, BCAA-associated metabolic signature is produced from a short-term, healthy, controlled, vegan diet challenge when compared with a healthy, controlled, omnivorous diet. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sulfur amino acids metabolism in magnesium deficient rats

Energy Technology Data Exchange (ETDEWEB)

Tojo, H.; Kosokawa, Y.; Yamaguchi, K.

1984-01-01

Effect of magnesium (Mg) deficiency on sulfur amino acid metabolism was investigated in rats. Young male rats were fed on the diet containing either 2.26 (deficient rats) or 63.18 mg Mg/100g diet (control and low protein rats) for 2 weeks. A remarkable decrease of body weight gain, serum Mg contents and a slight decreases in the hematological parameters such as Hb, Ht and RBC was observed, while the hepatic Mg and Ca was not significantly changed. Erythema and cramps were observed 5 days after feeding on the Mg-depleted diet. The hepatic glutathione and cysteine contents increased in Mg-deficient rats. However, no significant change of cysteine dioxygenase (CDO) activity and taurine content in Mg-deficient rat liver was observed. These results suggest that Mg deficiency affects the utilization and biosynthesis of hepatic glutathione but not the cysteine catabolism.

The Role of Microbial Amino Acid Metabolism in Host Metabolism

OpenAIRE

Evelien P. J. G. Neis; Cornelis H. C. Dejong; Sander S. Rensen

2015-01-01

Disruptions in gut microbiota composition and function are increasingly implicated in the pathogenesis of obesity, insulin resistance, and type 2 diabetes mellitus. The functional output of the gut microbiota, including short-chain fatty acids and amino acids, are thought to be important modulators underlying the development of these disorders. Gut bacteria can alter the bioavailability of amino acids by utilization of several amino acids originating from both alimentary and endogenous protei...

Branched-chain amino acids in metabolic signalling and insulin resistance

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Lynch, Christopher J.; Adams, Sean H.

2015-01-01

Branched-chain amino acids (BCAAs) are important nutrient signals that have direct and indirect effects. Frequently, BCAAs have been reported to mediate antiobesity effects, especially in rodent models. However, circulating levels of BCAAs tend to be increased in individuals with obesity and are associated with worse metabolic health and future insulin resistance or type 2 diabetes mellitus (T2DM). A hypothesized mechanism linking increased levels of BCAAs and T2DM involves leucine-mediated activation of the mammalian target of rapamycin complex 1 (mTORC1), which results in uncoupling of insulin signalling at an early stage. A BCAA dysmetabolism model proposes that the accumulation of mitotoxic metabolites (and not BCAAs per se) promotes β-cell mitochondrial dysfunction, stress signalling and apoptosis associated with T2DM. Alternatively, insulin resistance might promote aminoacidaemia by increasing the protein degradation that insulin normally suppresses, and/or by eliciting an impairment of efficient BCAA oxidative metabolism in some tissues. Whether and how impaired BCAA metabolism might occur in obesity is discussed in this Review. Research on the role of individual and model-dependent differences in BCAA metabolism is needed, as several genes (BCKDHA, PPM1K, IVD and KLF15) have been designated as candidate genes for obesity and/or T2DM in humans, and distinct phenotypes of tissue-specific branched chain ketoacid dehydrogenase complex activity have been detected in animal models of obesity and T2DM. PMID:25287287

Maillard reaction versus other nonenzymatic modifications in neurodegenerative processes.

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Pamplona, Reinald; Ilieva, Ekaterina; Ayala, Victoria; Bellmunt, Maria Josep; Cacabelos, Daniel; Dalfo, Esther; Ferrer, Isidre; Portero-Otin, Manuel

2008-04-01

Nonenzymatic protein modifications are generated from direct oxidation of amino acid side chains and from reaction of the nucleophilic side chains of specific amino acids with reactive carbonyl species. These reactions give rise to specific markers that have been analyzed in different neurodegenerative diseases sharing protein aggregation, such as Alzheimer's disease, Pick's disease, Parkinson's disease, dementia with Lewy bodies, Creutzfeldt-Jakob disease, and amyotrophic lateral sclerosis. Collectively, available data demonstrate that oxidative stress homeostasis, mitochondrial function, and energy metabolism are key factors in determining the disease-specific pattern of protein molecular damage. In addition, these findings suggest the lack of a "gold marker of oxidative stress," and, consequently, they strengthen the need for a molecular dissection of the nonenzymatic reactions underlying neurodegenerative processes.

Muscle protein degradation and amino acid metabolism during prolonged knee-extensor exercise in humans

DEFF Research Database (Denmark)

Van Hall, Gerrit; Saltin, B; Wagenmakers, A J

1999-01-01

to a substantial increase in net muscle protein degradation, and that a lowering of the starting muscle glycogen content leads to a further increase. The carbon atoms of the branched-chain amino acids (BCAA), glutamate, aspartate and asparagine, liberated by protein degradation, and the BCAA and glutamate......The aim of this study was to investigate whether prolonged one-leg knee-extensor exercise enhances net protein degradation in muscle with a normal or low glycogen content. Net amino acid production, as a measure of net protein degradation, was estimated from leg exchange and from changes...... in the concentrations of amino acids that are not metabolized in skeletal muscle. Experiments were performed at rest and during one-leg knee-extensor exercise in six subjects having one leg with a normal glycogen content and the other with a low glycogen content. Exercise was performed for 90 min at a workload of 60...

Gut microbiota metabolites, amino acid metabolites and improvements in insulin sensitivity and glucose metabolism: the POUNDS Lost trial.

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Heianza, Yoriko; Sun, Dianjianyi; Li, Xiang; DiDonato, Joseph A; Bray, George A; Sacks, Frank M; Qi, Lu

2018-06-02

Alterations in gut microbiota have been linked to host insulin resistance, diabetes and impaired amino acid metabolism. We investigated whether changes in gut microbiota-dependent metabolite of trimethylamine N-oxide (TMAO) and its nutrient precursors (choline and L-carnitine) were associated with improvements in glucose metabolism and diabetes-related amino acids in a weight-loss diet intervention. We included 504 overweight and obese adults who were randomly assigned to one of four energy-reduced diets varying in macronutrient intake. The 6-month changes (Δ) in TMAO, choline and L-carnitine levels after the intervention were calculated. Greater decreases in choline and L-carnitine were significantly (p<0.05) associated with greater improvements in fasting insulin concentrations and homeostasis model assessment of insulin resistance (HOMA-IR) at 6 months. The reduction of choline was significantly related to 2-year improvements in glucose and insulin resistance. We found significant linkages between dietary fat intake and ΔTMAO for changes in fasting glucose, insulin and HOMA-IR (p interaction <0.05); a greater increase in TMAO was related to lesser improvements in the outcomes among participants who consumed a high-fat diet. In addition, ΔL-carnitine and Δcholine were significantly related to changes in amino acids (including branched-chain and aromatic amino acids). Interestingly, the associations of ΔTMAO, Δcholine and ΔL-carnitine with diabetes-related traits were independent of the changes in amino acids. Our findings underscore the importance of changes in TMAO, choline and L-carnitine in improving insulin sensitivity during a weight-loss intervention for obese patients. Dietary fat intake may modify the associations of TMAO with insulin sensitivity and glucose metabolism. NCT00072995. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless

Metabolomics identifies perturbations in amino acid metabolism in the prefrontal cortex of the learned helplessness rat model of depression.

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Zhou, Xinyu; Liu, Lanxiang; Zhang, Yuqing; Pu, Juncai; Yang, Lining; Zhou, Chanjuan; Yuan, Shuai; Zhang, Hanping; Xie, Peng

2017-02-20

Major depressive disorder is a serious psychiatric condition associated with high rates of suicide and is a leading cause of health burden worldwide. However, the underlying molecular mechanisms of major depression are still essentially unclear. In our study, a non-targeted gas chromatography-mass spectrometry-based metabolomics approach was used to investigate metabolic changes in the prefrontal cortex of the learned helplessness (LH) rat model of depression. Body-weight measurements and behavioral tests including the active escape test, sucrose preference test, forced swimming test, elevated plus-maze and open field test were used to assess changes in the behavioral spectrum after inescapable footshock stress. Rats in the stress group exhibited significant learned helpless and depression-like behaviors, while without any significant change in anxiety-like behaviors. Using multivariate and univariate statistical analysis, a total of 18 differential metabolites were identified after the footshock stress protocol. Ingenuity Pathways Analysis and MetaboAnalyst were applied for predicted pathways and biological functions analysis. "Amino Acid Metabolism, Molecule Transport, Small Molecule Biochemistry" was the most significantly altered network in the LH model. Amino acid metabolism, particularly glutamate metabolism, cysteine and methionine metabolism, arginine and proline metabolism, was significantly perturbed in the prefrontal cortex of LH rats. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Metabolic Myopathies.

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Tarnopolsky, Mark A

2016-12-01

Metabolic myopathies are genetic disorders that impair intermediary metabolism in skeletal muscle. Impairments in glycolysis/glycogenolysis (glycogen-storage disease), fatty acid transport and oxidation (fatty acid oxidation defects), and the mitochondrial respiratory chain (mitochondrial myopathies) represent the majority of known defects. The purpose of this review is to develop a diagnostic and treatment algorithm for the metabolic myopathies. The metabolic myopathies can present in the neonatal and infant period as part of more systemic involvement with hypotonia, hypoglycemia, and encephalopathy; however, most cases present in childhood or in adulthood with exercise intolerance (often with rhabdomyolysis) and weakness. The glycogen-storage diseases present during brief bouts of high-intensity exercise, whereas fatty acid oxidation defects and mitochondrial myopathies present during a long-duration/low-intensity endurance-type activity or during fasting or another metabolically stressful event (eg, surgery, fever). The clinical examination is often normal between acute events, and evaluation involves exercise testing, blood testing (creatine kinase, acylcarnitine profile, lactate, amino acids), urine organic acids (ketones, dicarboxylic acids, 3-methylglutaconic acid), muscle biopsy (histology, ultrastructure, enzyme testing), MRI/spectroscopy, and targeted or untargeted genetic testing. Accurate and early identification of metabolic myopathies can lead to therapeutic interventions with lifestyle and nutritional modification, cofactor treatment, and rapid treatment of rhabdomyolysis.

Adipose Tissue Dysfunction and Altered Systemic Amino Acid Metabolism Are Associated with Non-Alcoholic Fatty Liver Disease.

Directory of Open Access Journals (Sweden)

Sulin Cheng

Full Text Available Fatty liver is a major cause of obesity-related morbidity and mortality. The aim of this study was to identify early metabolic alterations associated with liver fat accumulation in 50- to 55-year-old men (n = 49 and women (n = 52 with and without NAFLD.Hepatic fat content was measured using proton magnetic resonance spectroscopy (1H MRS. Serum samples were analyzed using a nuclear magnetic resonance (NMR metabolomics platform. Global gene expression profiles of adipose tissues and skeletal muscle were analyzed using Affymetrix microarrays and quantitative PCR. Muscle protein expression was analyzed by Western blot.Increased branched-chain amino acid (BCAA, aromatic amino acid (AAA and orosomucoid were associated with liver fat accumulation already in its early stage, independent of sex, obesity or insulin resistance (p<0.05 for all. Significant down-regulation of BCAA catabolism and fatty acid and energy metabolism was observed in the adipose tissue of the NAFLD group (p<0.001for all, whereas no aberrant gene expression in the skeletal muscle was found. Reduced BCAA catabolic activity was inversely associated with serum BCAA and liver fat content (p<0.05 for all.Liver fat accumulation, already in its early stage, is associated with increased serum branched-chain and aromatic amino acids. The observed associations of decreased BCAA catabolism activity, mitochondrial energy metabolism and serum BCAA concentration with liver fat content suggest that adipose tissue dysfunction may have a key role in the systemic nature of NAFLD pathogenesis.

Oncogenic MYC Activates a Feedforward Regulatory Loop Promoting Essential Amino Acid Metabolism and Tumorigenesis.

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Yue, Ming; Jiang, Jue; Gao, Peng; Liu, Hudan; Qing, Guoliang

2017-12-26

Most tumor cells exhibit obligatory demands for essential amino acids (EAAs), but the regulatory mechanisms whereby tumor cells take up EAAs and EAAs promote malignant transformation remain to be determined. Here, we show that oncogenic MYC, solute carrier family (SLC) 7 member 5 (SLC7A5), and SLC43A1 constitute a feedforward activation loop to promote EAA transport and tumorigenesis. MYC selectively activates Slc7a5 and Slc43a1 transcription through direct binding to specific E box elements within both genes, enabling effective EAA import. Elevated EAAs, in turn, stimulate Myc mRNA translation, in part through attenuation of the GCN2-eIF2α-ATF4 amino acid stress response pathway, leading to MYC-dependent transcriptional amplification. SLC7A5/SLC43A1 depletion inhibits MYC expression, metabolic reprogramming, and tumor cell growth in vitro and in vivo. These findings thus reveal a MYC-SLC7A5/SLC43A1 signaling circuit that underlies EAA metabolism, MYC deregulation, and tumorigenesis. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Time-course changes in circulating branched-chain amino acid levels and metabolism in obese Yucatan minipig.

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Polakof, Sergio; Rémond, Didier; David, Jérémie; Dardevet, Dominique; Savary-Auzeloux, Isabelle

2018-06-01

High-fat high-sucrose diet (HFHS) overfeeding is one of the main factors responsible for the increased prevalence of metabolic disorders. Elevated levels of branched-chain amino acids (BCAAs) have been associated with metabolic dysfunctions, including insulin resistance (IR). The aim of this study was to elucidate whether elevated BCAA levels are the cause or the consequence of IR and to determine the mechanisms and tissues involved in such a phenotype. We performed a 2-mo follow-up on minipigs overfed an HFHS diet and focused on kinetics fasting and postprandial (PP) BCAA levels and BCAA catabolism in key tissues. The study of the fasting BCAA elevation reveals that BCAA accumulation in the plasma compartment is well correlated with IR markers and body weight. Furthermore, the PP excursion of BCAA levels after the last HFHS meal was exacerbated when compared with that of the first meal, suggesting a reduced amino acid oxidation potential. Although only minor changes in BCAA metabolism were observed in liver, muscle, and the visceral adipose tissue, the oxidative deamination potential of the subcutaneous adipose tissue was blunted after 60 d of HFHS feeding. To our knowledge, the present results demonstrated for the first time in a swine model of obesity and IR, the existence of a phenotype related to high-circulating BCAA levels and metabolic dysregulation. The oxidative BCAA capacity reduction specifically in the subcutaneous adipose tissue emerges, at least in the present swine model, as the more plausible metabolic explanation for the elevated blood BCAA phenotype. Copyright © 2017 Elsevier Inc. All rights reserved.

Metabolomic analysis of alterations in lipid oxidation, carbohydrate and amino acid metabolism in dairy goats caused by exposure to Aflotoxin B1.

Science.gov (United States)

Cheng, Jianbo; Huang, Shuai; Fan, Caiyun; Zheng, Nan; Zhang, Yangdong; Li, Songli; Wang, Jiaqi

2017-11-01

The purposes of this study were to investigate the systemic and characteristic metabolites in the serum of dairy goats induced by aflatoxin B1 (AFB1) exposure and to further understand the endogenous metabolic alterations induced by it. A nuclear magnetic resonance (NMR)-based metabonomic approach was used to analyse the metabolic alterations in dairy goats that were induced by low doses of AFB1 (50 µg/kg DM). We found that AFB1 exposure caused significant elevations of glucose, citrate, acetate, acetoacetate, betaine, and glycine yet caused reductions of lactate, ketone bodies (acetate, β-hydroxybutyrate), amino acids (citrulline, leucine/isoleucine, valine, creatine) and cell membrane structures (choline, lipoprotein, N-acetyl glycoproteins) in the serum. These data indicated that AFB1 caused endogenous metabolic changes in various metabolic pathways, including cell membrane-associated metabolism, the tricarboxylic acid cycle, glycolysis, lipids, and amino acid metabolism. These findings provide both a comprehensive insight into the metabolic aspects of AFB1-induced adverse effects on dairy goats and a method for monitoring dairy animals exposed to low doses of AFB1.

Potential use of carbon-11 labeled alpha-aminoisobutyric acid (AIB) as an in vivo tracer of amino acid uptake in differing metabolic states

International Nuclear Information System (INIS)

Conti, P.S.; Starnes, H.F.; Brennan, M.F.

1986-01-01

AIB has been used as a model amino acid for the evaluation of alanine-preferring amino acid transport. Hormonal factors and starvation alter the tissue distribution of amino acids, particularly in liver and muscle. With positron emission tomography and labeling of biochemical tracers with C-11, (t1/2=20.4 min), it is now possible to study amino acid kinetics in vivo using external imaging. In order to investigate the utility of C-11 AIB as an in vivo tracer of altered tissue metabolism, C-14 AIB was studied in groups of rats with either streptozotocin-induced diabetes, insulin-induced hypoglycemia or starvation. The data suggest an increased amino acid uptake in liver in starvation, an increased uptake in muscle in response to insulin and associated hypoglycemia and decreased transport in muscle in starvation, as seen by other investigators. These results suggest that C-11 AIB may be useful as an in vivo monitor of metabolic changes in body tissues

Muscle metabolism and whole blood amino acid profile in patients with liver disease.

Science.gov (United States)

Dam, Gitte; Sørensen, Michael; Buhl, Mads; Sandahl, Thomas D; Møller, Niels; Ott, Peter; Vilstrup, Hendrik

2015-01-01

Branched-chain amino acids (BCAA) are used in liver cirrhosis to promote protein synthesis, support ammonia detoxification, and treat hepatic encephalopathy. Cirrhosis leads to subnormal BCAA plasma concentrations and studies indicate that levels are decreased due to their role in muscle ammonia removal. Muscle contribution has not been fully elucidated. We studied muscle amino acid metabolism in six healthy subjects, 13 cirrhosis patients and six patients with an episode of alcoholic hepatitis. Subjects had catheters inserted into the femoral artery and vein to obtain arterial (A) and venous (V) concentrations of amino acids (μmol/L blood). BCAA concentrations were lower in patients with cirrhosis compared to healthy subjects (p BCAA uptake was variable and on average higher in patients with alcoholic hepatitis and patients with stable cirrhosis compared to healthy subjects (mean A-V difference 0.5 and 32 vs. - 12 μmol/L blood) (p = 0.22). The release of aromatic amino acids (AAA) was comparable in the three groups (P > 0.30). The BCAA/AAA (Fischer's ratio) was lower in patients with cirrhosis and patients with alcoholic hepatitis compared to healthy subjects (mean 1.65, 1.17 and 2.73, both p BCAA and higher AAA blood concentrations compared to healthy subjects. The trend towards an increased muscle uptake of BCAA may have contributed but this was not significant.

PGC-1α-mediated branched-chain amino acid metabolism in the skeletal muscle.

Science.gov (United States)

Hatazawa, Yukino; Tadaishi, Miki; Nagaike, Yuta; Morita, Akihito; Ogawa, Yoshihiro; Ezaki, Osamu; Takai-Igarashi, Takako; Kitaura, Yasuyuki; Shimomura, Yoshiharu; Kamei, Yasutomi; Miura, Shinji

2014-01-01

Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC-1α) is a coactivator of various nuclear receptors and other transcription factors, which is involved in the regulation of energy metabolism, thermogenesis, and other biological processes that control phenotypic characteristics of various organ systems including skeletal muscle. PGC-1α in skeletal muscle is considered to be involved in contractile protein function, mitochondrial function, metabolic regulation, intracellular signaling, and transcriptional responses. Branched-chain amino acid (BCAA) metabolism mainly occurs in skeletal muscle mitochondria, and enzymes related to BCAA metabolism are increased by exercise. Using murine skeletal muscle overexpressing PGC-1α and cultured cells, we investigated whether PGC-1α stimulates BCAA metabolism by increasing the expression of enzymes involved in BCAA metabolism. Transgenic mice overexpressing PGC-1α specifically in the skeletal muscle had increased the expression of branched-chain aminotransferase (BCAT) 2, branched-chain α-keto acid dehydrogenase (BCKDH), which catabolize BCAA. The expression of BCKDH kinase (BCKDK), which phosphorylates BCKDH and suppresses its enzymatic activity, was unchanged. The amount of BCAA in the skeletal muscle was significantly decreased in the transgenic mice compared with that in the wild-type mice. The amount of glutamic acid, a metabolite of BCAA catabolism, was increased in the transgenic mice, suggesting the activation of muscle BCAA metabolism by PGC-1α. In C2C12 cells, the overexpression of PGC-1α significantly increased the expression of BCAT2 and BCKDH but not BCKDK. Thus, PGC-1α in the skeletal muscle is considered to significantly contribute to BCAA metabolism.

Essential polyunsaturated fatty acids in plasma and erythrocytes of children with inborn errors of amino acid metabolism.

NARCIS (Netherlands)

Vlaardingerbroek, H.; Hornstra, G.; Koning, T.J.; Smeitink, J.A.M.; Bakker, H.D.; Klerk, H. de; Rubio-Gozalbo, M.E.

2006-01-01

Essential fatty acids (EFAs), and their longer-chain more-unsaturated derivatives (LCPUFAs) in particular, are essential for normal growth and cognitive development during childhood. Children with inborn errors of amino acid metabolism represent a risk population for a reduced LCPUFA status because

Effects of alkali stress on growth, free amino acids and carbohydrates metabolism in Kentucky bluegrass (Poa pratensis).

Science.gov (United States)

Zhang, Pingping; Fu, Jinmin; Hu, Longxing

2012-10-01

Soil alkalization is one of the most prominent adverse environmental factors limiting plant growth, while alkali stress affects amino acids and carbohydrates metabolism. The objective of this study was conducted to investigate the effects of alkali stress on growth, amino acids and carbohydrates metabolism in Kentucky bluegrass (Poa pratensis). Seventy-day-old plants were subjected to four pH levels: 6.0 (control), 8.0 (low), 9.4 (moderate) and 10.3 (severe) for 7 days. Moderate to severe alkali stress (pH >9.4) caused a significant decline in turf quality and growth rate in Kentucky bluegrass. Soluble protein was unchanged in shoots, but decreased in roots as pH increased. The levels of amino acids was kept at the same level as control level at 4 days after treatment (DAT) in shoots, but greater at 7 DAT, when plants were subjected to severe (pH 10.3) alkali stress. The alkali stressed plants had a greater level of starch, water soluble carbohydrate and sucrose content, but lower level of fructose and glucose. Fructan and total non-structural carbohydrate (TNC) increased at 4 DAT and decreased at 7 DAT for alkali stressed plants. These results suggested that the decrease in fructose and glucose contributed to the growth reduction under alkali stress, while the increase in amino acids, sucrose and storage form of carbohydrate (fructan, starch) could be an adaptative mechanism in Kentucky bluegrass under alkali stress.

Metabolic profiling of plasma amino acids shows that histidine increases following the consumption of pork

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Samman S

2014-06-01

Full Text Available Samir Samman,1 Ben Crossett,2 Miles Somers,1 Kirstine J Bell,1 Nicole T Lai,1,3 David R Sullivan,3 Peter Petocz4 1Discipline of Nutrition and Metabolism, 2Discipline of Proteomics and Biotechnology, School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia; 3Department of Clinical Biochemistry, Royal Prince Alfred Hospital, Sydney, NSW, Australia; 4Department of Statistics, Macquarie University, Sydney, NSW, Australia Abstract: Amino acid (AA status is determined by factors including nutrition, metabolic rate, and interactions between the metabolism of AA, carbohydrates, and lipids. Analysis of the plasma AA profile, together with markers of glucose and lipid metabolism, will shed light on metabolic regulation. The objectives of this study were to investigate the acute responses to the consumption of meals containing either pork (PM or chicken (CM, and to identify relationships between plasma AA and markers of glycemic and lipemic control. A secondary aim was to explore AA predictors of plasma zinc concentrations. Ten healthy adults participated in a postprandial study on two separate occasions. In a randomized cross-over design, participants consumed PM or CM. The concentrations of 21 AA, glucose, insulin, triglycerides, nonesterified fatty acids, and zinc were determined over 5 hours postprandially. The meal composition did not influence glucose, insulin, triglyceride, nonesterified fatty acid, or zinc concentrations. Plasma histidine was higher following the consumption of PM (P=0.014, with consistently higher changes observed after 60 minutes (P<0.001. Greater percentage increases were noted at limited time points for valine and leucine + isoleucine in those who consumed CM compared to PM. In linear regression, some AAs emerged as predictors of the metabolic responses, irrespective of the meal that was consumed. The present study demonstrates that a single meal of PM or CM produces a differential profile of AA in the

Bioactive Compounds Derived from the Yeast Metabolism of Aromatic Amino Acids during Alcoholic Fermentation

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Albert Mas

2014-01-01

Full Text Available Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements.

Inducible arginase 1 deficiency in mice leads to hyperargininemia and altered amino acid metabolism.

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Yuan Yan Sin

Full Text Available Arginase deficiency is a rare autosomal recessive disorder resulting from a loss of the liver arginase isoform, arginase 1 (ARG1, which is the final step in the urea cycle for detoxifying ammonia. ARG1 deficiency leads to hyperargininemia, characterized by progressive neurological impairment, persistent growth retardation and infrequent episodes of hyperammonemia. Using the Cre/loxP-directed conditional gene knockout system, we generated an inducible Arg1-deficient mouse model by crossing "floxed" Arg1 mice with CreER(T2 mice. The resulting mice (Arg-Cre die about two weeks after tamoxifen administration regardless of the starting age of inducing the knockout. These treated mice were nearly devoid of Arg1 mRNA, protein and liver arginase activity, and exhibited symptoms of hyperammonemia. Plasma amino acid analysis revealed pronounced hyperargininemia and significant alterations in amino acid and guanidino compound metabolism, including increased citrulline and guanidinoacetic acid. Despite no alteration in ornithine levels, concentrations of other amino acids such as proline and the branched-chain amino acids were reduced. In summary, we have generated and characterized an inducible Arg1-deficient mouse model exhibiting several pathologic manifestations of hyperargininemia. This model should prove useful for exploring potential treatment options of ARG1 deficiency.

Metabolism-oriented amino acid requirement determination by means of the catabolic rates of 14C- and 15N-labelled lysine under maintenance

International Nuclear Information System (INIS)

Simon, O.; Bergner, H.; Adam, K.

1977-01-01

Male Wistar rats (of 60 g live weight) allotted in 10 groups were fed diets with gradually increasing lysine levels ranging from 1.4 to 7.4 g lysine/16 g N. Feed intake was restricted so much that the experimental animals did not change their live weights during the last 3 days of the 8-day experimental period. On the 7the experimental day, 4 animals of each group were injected, i. p. 14 C-L-lysine, the 14 CO 2 -excretion being subsequently measured over a period of 2 hours. On the next day, 6 animals of each group were applied an i. p. injection of 15 N-L-lysine, the urine being collected over the following 24-hour period to measure the 15 N-frequency. Applying both labelling methods, an increased catabolisation of the amino acid was observed after the metabolically necessary lysine requirement had been covered. The methods are very sensitive and revealed, under the experimental conditions chosen, a lysine requirement coverage of about 3 g lysine/16 g N. The possibility of using also 15 N-labelled compounds in the metabolism-oriented amino acid requirement determination is likely to facilitate the transfer of the methodology to farm animals would thus allow to study the amino acid requirement of man. The metabolism-oriented amino acid requirement determination will likewise allow to estimate exact amino acid requirement data under conditions that cannot be rated on the basis of productive yields. (author)

Characterization of amino acid metabolism by cultured rat kidney cells: Study with 15N

International Nuclear Information System (INIS)

Nissim, I.; States, B.; Yudkoff, M.; Segal, S.

1987-01-01

The present study evaluates the metabolism of glutamine and glutamate by normal rat kidney (NRK) cells. The major aim was to evaluate the effect of acute acidosis on the metabolism of amino acid and ammonia formation by cultured NRK cells. Experiments at either pH 7.0 or 7.4 were conducted with phosphate-buffered saline supplemented with either 1 mM [5- 15 N]glutamine, [2- 15 N]glutamine, or [ 15 N]glutamate. Incubation with either glutamine or glutamate as a precursor showed that production of ammonia and glucose was increased significantly at pH 7.0 vs 7.4. In experiments with [5- 15 N]glutamine, the authors found that ∼57 and 43% of ammonia N was derived from 5-N of glutamine at pH 7.4 and 7.0, respectively. Three major metabolic pathways of [2- 15 N]glutamine or [ 15 N]glutamate disposal were identified: (1) transamination reactions involving the pH-independent formation of [ 15 N] aspartate and [ 15 N]alanine; (2) the synthesis of [6- 15 NH 2 ]adenine nucleotide, a process more active at pH 7.4 vs. 7.0; and (3) glutamine synthesis from [ 15 N]glutamate, especially at pH 7.4. The data indicate that NRK cells in culture consume glutamine and glutamate and generate ammonia and various amino acids, depending on the H + concentration in the media. The studies suggest that these cell lines may provide a useful model for studying various aspects of the effect of pH on rat renal ammoniagenesis

PGC-1α-mediated branched-chain amino acid metabolism in the skeletal muscle.

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Yukino Hatazawa

Full Text Available Peroxisome proliferator-activated receptor (PPAR γ coactivator 1α (PGC-1α is a coactivator of various nuclear receptors and other transcription factors, which is involved in the regulation of energy metabolism, thermogenesis, and other biological processes that control phenotypic characteristics of various organ systems including skeletal muscle. PGC-1α in skeletal muscle is considered to be involved in contractile protein function, mitochondrial function, metabolic regulation, intracellular signaling, and transcriptional responses. Branched-chain amino acid (BCAA metabolism mainly occurs in skeletal muscle mitochondria, and enzymes related to BCAA metabolism are increased by exercise. Using murine skeletal muscle overexpressing PGC-1α and cultured cells, we investigated whether PGC-1α stimulates BCAA metabolism by increasing the expression of enzymes involved in BCAA metabolism. Transgenic mice overexpressing PGC-1α specifically in the skeletal muscle had increased the expression of branched-chain aminotransferase (BCAT 2, branched-chain α-keto acid dehydrogenase (BCKDH, which catabolize BCAA. The expression of BCKDH kinase (BCKDK, which phosphorylates BCKDH and suppresses its enzymatic activity, was unchanged. The amount of BCAA in the skeletal muscle was significantly decreased in the transgenic mice compared with that in the wild-type mice. The amount of glutamic acid, a metabolite of BCAA catabolism, was increased in the transgenic mice, suggesting the activation of muscle BCAA metabolism by PGC-1α. In C2C12 cells, the overexpression of PGC-1α significantly increased the expression of BCAT2 and BCKDH but not BCKDK. Thus, PGC-1α in the skeletal muscle is considered to significantly contribute to BCAA metabolism.

Anaerobic metabolism of nitroaromatic compounds by sulfate-reducing and methanogenic bacteria

Energy Technology Data Exchange (ETDEWEB)

Boopathy, R. [Argonne National Lab., IL (United States); Kulpa, C.F. [Notre Dame Univ., IN (United States). Dept. of Biological Sciences

1994-06-01

Ecological observations suggest that sulfate-reducing and methanogenic bacteria might metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment, but this ability had not been demonstrated until recently. Most studies on the microbial metabolism of nitroaromatic compounds used aerobic microorganisms. In most cases no mineralization of nitroaromatics occurs, and only superficial modifications of the structures are reported. However, under anaerobic sulfate-reducing conditions, the nitroaromatic compounds reportedly undergo a series of reductions with the formation of amino compounds. For example, trinitrotoluene under sulfate-reducing conditions is reduced to triaminotoluene by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of ammonia from triaminotoluene is achieved by reductive deamination catalyzed by the enzyme reductive deaminase, with the production of ammonia and toluene. Some sulfate reducers can metabolize toluene to CO{sub 2}. Similar metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. Many methanogenic bacteria can reduce nitroaromatic compounds to amino compounds. In this paper we review the anaerobic metabolic processes of nitroaromatic compounds under sulfate-reducing And methanogenic conditions.

Anaerobic metabolism of nitroaromatic compounds by sulfate-reducing and methanogenic bacteria

International Nuclear Information System (INIS)

Boopathy, R.; Kulpa, C.F.

1994-01-01

Ecological observations suggest that sulfate-reducing and methanogenic bacteria might metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment, but this ability had not been demonstrated until recently. Most studies on the microbial metabolism of nitroaromatic compounds used aerobic microorganisms. In most cases no mineralization of nitroaromatics occurs, and only superficial modifications of the structures are reported. However, under anaerobic sulfate-reducing conditions, the nitroaromatic compounds reportedly undergo a series of reductions with the formation of amino compounds. For example, trinitrotoluene under sulfate-reducing conditions is reduced to triaminotoluene by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of ammonia from triaminotoluene is achieved by reductive deamination catalyzed by the enzyme reductive deaminase, with the production of ammonia and toluene. Some sulfate reducers can metabolize toluene to CO 2 . Similar metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. Many methanogenic bacteria can reduce nitroaromatic compounds to amino compounds. In this paper we review the anaerobic metabolic processes of nitroaromatic compounds under sulfate-reducing And methanogenic conditions

Irreversible inactivation of snake venom l-amino acid oxidase by covalent modification during catalysis of l-propargylglycine☆

Science.gov (United States)

Mitra, Jyotirmoy; Bhattacharyya, Debasish

2013-01-01

Snake venom l-amino acid oxidase (SV-LAAO, a flavor-enzyme) has attracted considerable attention due to its multifunctional nature, which is manifest in diverse clinical and biological effects such as inhibition of platelet aggregation, induction of cell apoptosis and cytotoxicity against various cells. The majority of these effects are mediated by H2O2 generated during the catalytic conversion of l-amino acids. The substrate analog l-propargylglycine (LPG) irreversibly inhibited the enzyme from Crotalus adamanteus and Crotalus atrox in a dose- and time-dependent manner. Inactivation was irreversible which was significantly protected by the substrate l-phenylalanine. A Kitz–Wilson replot of the inhibition kinetics suggested formation of reversible enzyme–LPG complex, which occurred prior to modification and inactivation of the enzyme. UV–visible and fluorescence spectra of the enzyme and the cofactor strongly suggested formation of covalent adduct between LPG and an active site residue of the enzyme. A molecular modeling study revealed that the FAD-binding, substrate-binding and the helical domains are conserved in SV-LAAOs and both His223 and Arg322 are the important active site residues that are likely to get modified by LPG. Chymotrypsin digest of the LPG inactivated enzyme followed by RP-HPLC and MALDI mass analysis identified His223 as the site of modification. The findings reported here contribute towards complete inactivation of SV-LAAO as a part of snake envenomation management. PMID:23772385

Radiolabeled amino acids : Basic aspects and clinical applications in oncology

NARCIS (Netherlands)

Jager, PL; Vaalburg, W; Pruim, J; de Vries, EGE; Langen, KJ; Piers, DA

As the applications of metabolic imaging are expanding, radiolabeled amino acids may gain increased clinical interest, This review first describes the basic aspects of amino acid metabolism, then continues with basic aspects of radiolabeled amino acids, and finally describes clinical applications,

Branched-Chain Amino Acids

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Matteo Ghiringhelli

2015-07-01

Full Text Available Our study is focused on evaluation and use of the most effective and correct nutrients. In particular, our attention is directed to the role of certain amino acids in cachectic patients. During parenteral nutrition in humans, physician already associates in the PN-bags different formulations including amino acids, lipids and glucose solutions or essential amino acids solution alone or exclusively branched-chain amino acids (BCAA. Studies investigated the effects of dietary BCAA ingestion on different diseases and conditions such as obesity and metabolic disorders, liver disease, muscle atrophy, cancer, impaired immunity or injuries (surgery, trauma, burns, and sepsis. BCAAs have been shown to affect gene expression, protein metabolism, apoptosis and regeneration of hepatocytes, and insulin resistance. They have also been shown to inhibit the proliferation of liver cancer cells in vitro, and are essential for lymphocyte proliferation and dendritic cell maturation. Oral or parenteral administration of these three amino acids will allow us to evaluate the real efficacy of these compounds during a therapy to treat malnutrition in subjects unable to feed themselves.

Perturbations of amino acid metabolism associated with glyphosate-dependent inhibition of shikimic acid metabolism affect cellular redox homeostasis and alter the abundance of proteins involved in photosynthesis and photorespiration.

Science.gov (United States)

Vivancos, Pedro Diaz; Driscoll, Simon P; Bulman, Christopher A; Ying, Liu; Emami, Kaveh; Treumann, Achim; Mauve, Caroline; Noctor, Graham; Foyer, Christine H

2011-09-01

The herbicide glyphosate inhibits the shikimate pathway of the synthesis of amino acids such as phenylalanine, tyrosine, and tryptophan. However, much uncertainty remains concerning precisely how glyphosate kills plants or affects cellular redox homeostasis and related processes in glyphosate-sensitive and glyphosate-resistant crop plants. To address this issue, we performed an integrated study of photosynthesis, leaf proteomes, amino acid profiles, and redox profiles in the glyphosate-sensitive soybean (Glycine max) genotype PAN809 and glyphosate-resistant Roundup Ready Soybean (RRS). RRS leaves accumulated much more glyphosate than the sensitive line but showed relatively few changes in amino acid metabolism. Photosynthesis was unaffected by glyphosate in RRS leaves, but decreased abundance of photosynthesis/photorespiratory pathway proteins was observed together with oxidation of major redox pools. While treatment of a sensitive genotype with glyphosate rapidly inhibited photosynthesis and triggered the appearance of a nitrogen-rich amino acid profile, there was no evidence of oxidation of the redox pools. There was, however, an increase in starvation-associated and defense proteins. We conclude that glyphosate-dependent inhibition of soybean leaf metabolism leads to the induction of defense proteins without sustained oxidation. Conversely, the accumulation of high levels of glyphosate in RRS enhances cellular oxidation, possibly through mechanisms involving stimulation of the photorespiratory pathway.

The cerebral metabolism of amino acids and related metabolites as studied by 13C and 14C labelling

International Nuclear Information System (INIS)

Hassel, B.

1995-11-01

The present investigations show the feasibility of analyzing the cerebral metabolism of amino acids and related metabolites by 13 C-and 14 C-labelling using labelled acetate and glucose as markers for glial and neuronal metabolism, respectively. Using [ 13 C[acetate, it was shown that glial cells export ∼60% of their TCA cycle intermediates, mostly as glutamine, and that this glutamine is used by neurons partly as an energy reserve, and partly it is converted directly to glutamate and GABA. Using [ 13 C[glucose, the glial process or pyruvate carboxylation was shown to compensate fully for the loss of glutamine. The mechanism of action of two neurotoxins, fluorocitrate and 3-nitropropionate was elucidated. The latter toxin was shown to inhibit the TCA cycle of GABAergic neurons selectively. Formation of pyruvate and lactate from glial TCA cycle intermediates was demonstrated in vivo. This pathway may be important for glial inactivation of transmitter glutamate and GABA. The results illustrate glianeuronal interactions, and they suggest the applicability of 13 CNMR spectroscopy to the detailed study of the cerebral metabolism of amino acids in the intact, unanesthetized human brain. 174 refs

Amino acid metabolism of Lemna minor L

International Nuclear Information System (INIS)

Rhodes, D.; Rich, P.J.; Brunk, D.G.

1989-01-01

A serious limitation to the use of N(O,S)-heptafluorobutyryl isobutyl amino acid derivatives in the analysis of 15 N-labeling kinetics of amino acids in plant tissues, is that the amides glutamine and asparagine undergo acid hydrolysis to glutamate and aspartate, respectively, during derivatization. This led us to consider an alternative procedure for derivatization of glutamine and asparagine with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide in pyridine. Gas chromatography-mass spectrometry yielded fragment ions (M-57) of mass 417 and 431 for the [ 14 N]asparagine and [ 14 N]glutamine derivatives, respectively, suitable for monitoring unlabeled, single- 15 N- and double- 15 N-labeled amide species from the ion clusters at mass to charge ratio (m/z) 415 to 423 for asparagine, and m/z 429 to 437 for glutamine. From separate analyses of the specific isotope abundance of the amino-N groups of asparagine and glutamine as their N-heptafluorobutyryl isobutyl derivatives, the specific amide-[ 15 N] abundance of these amino acids was determined

High Glucose-Induced Cardiomyocyte Death May Be Linked to Unbalanced Branched-Chain Amino Acids and Energy Metabolism

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Xi Zhang

2018-04-01

Full Text Available High glucose-induced cardiomyocyte death is a common symptom in advanced-stage diabetic patients, while its metabolic mechanism is still poorly understood. The aim of this study was to explore metabolic changes in high glucose-induced cardiomyocytes and the heart of streptozotocin-induced diabetic rats by 1H-NMR-based metabolomics. We found that high glucose can promote cardiomyocyte death both in vitro and in vivo studies. Metabolomic results show that several metabolites exhibited inconsistent variations in vitro and in vivo. However, we also identified a series of common metabolic changes, including increases in branched-chain amino acids (BCAAs: leucine, isoleucine and valine as well as decreases in aspartate and creatine under high glucose condition. Moreover, a reduced energy metabolism could also be a common metabolic characteristic, as indicated by decreases in ATP in vitro as well as AMP, fumarate and succinate in vivo. Therefore, this study reveals that a decrease in energy metabolism and an increase in BCAAs metabolism could be implicated in high glucose-induced cardiomyocyte death.

Laboratory generated artifacts in plasma amino acid quantitation

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Ananth Nanjunda Rao

2002-10-01

Full Text Available The pace of physicians? involvement in amino acid metabolism has been enormous in the last five decades. With further development of technology to identify and quantitate upto picomoles of amino acids, their metabolites and related peptides, diagnosis and effective medical intervention in cases of inherited metabolic disorders have been well within the reach of the clinician. Automatic amino acid analyzers have become an essential part of major medical and research centers around the world. The technology has come indeed as a boon to physicians who in particular deal with inherited defects of amino acid metabolism. However, the technology comes with the risk of major deviations from the actual results when a few minor variations are not looked into. Trivial variations in basic steps of obtaining the sample, the choice of anticoagulant, hemolysis etc. can cause significant variations in the resulting values, particularly while dealing with inherited defects of amino acid metabolism and their treatment/management. Effects of such factors are revisited here for the benefit of the modern day laboratory personnel.

LED Lighting – Modification of Growth, Metabolism, Yield and Flour Composition in Wheat by Spectral Quality and Intensity

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István Monostori

2018-05-01

Full Text Available The use of light-emitting diode (LED technology for plant cultivation under controlled environmental conditions can result in significant reductions in energy consumption. However, there is still a lack of detailed information on the lighting conditions required for optimal growth of different plant species and the effects of light intensity and spectral composition on plant metabolism and nutritional quality. In the present study, wheat plants were grown under six regimens designed to compare the effects of LED and conventional fluorescent lights on growth and development, leaf photosynthesis, thiol and amino acid metabolism as well as grain yield and flour quality of wheat. Benefits of LED light sources over fluorescent lighting were manifested in both yield and quality of wheat. Elevated light intensities made possible with LEDs increased photosynthetic activity, the number of tillers, biomass and yield. At lower light intensities, blue, green and far-red light operated antagonistically during the stem elongation period. High photosynthetic activity was achieved when at least 50% of red light was applied during cultivation. A high proportion of blue light prolonged the juvenile phase, while the shortest flowering time was achieved when the blue to red ratio was around one. Blue and far-red light affected the glutathione- and proline-dependent redox environment in leaves. LEDs, especially in Blue, Pink and Red Low Light (RedLL regimens improved flour quality by modifying starch and protein content, dough strength and extensibility as demonstrated by the ratios of high to low molecular weight glutenins, ratios of glutenins to gliadins and gluten spread values. These results clearly show that LEDs are efficient for experimental wheat cultivation, and make it possible to optimize the growth conditions and to manipulate metabolism, yield and quality through modification of light quality and quantity.

Repletion of branched chain amino acids reverses mTORC1 signaling but not improved metabolism during dietary protein dilution

DEFF Research Database (Denmark)

Maida, Adriano; Chan, Jessica S K; Sjøberg, Kim Anker

2017-01-01

OBJECTIVE: Dietary protein dilution (PD) has been associated with metabolic advantages such as improved glucose homeostasis and increased energy expenditure. This phenotype involves liver-induced release of FGF21 in response to amino acid insufficiency; however, it has remained unclear whether...... dietary dilution of specific amino acids (AAs) is also required. Circulating branched chain amino acids (BCAAs) are sensitive to protein intake, elevated in the serum of obese humans and mice and thought to promote insulin resistance. We tested whether replenishment of dietary BCAAs to an AA-diluted (AAD......) diet is sufficient to reverse the glucoregulatory benefits of dietary PD. METHODS: We conducted AA profiling of serum from healthy humans and lean and high fat-fed or New Zealand obese (NZO) mice following dietary PD. We fed wildtype and NZO mice one of three amino acid defined diets: control, total...

Epstein–Barr Virus-Induced Metabolic Rearrangements in Human B-Cell Lymphomas

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Pier P. Piccaluga

2018-06-01

Full Text Available Tumor metabolism has been the object of several studies in the past, leading to the pivotal observation of a consistent shift toward aerobic glycolysis (so-called Warburg effect. More recently, several additional investigations proved that tumor metabolism is profoundly affected during tumorigenesis, including glucose, lipid and amino-acid metabolism. It is noticeable that metabolic reprogramming can represent a suitable therapeutic target in many cancer types. Epstein–Barr virus (EBV was the first virus linked with cancer in humans when Burkitt lymphoma (BL was described. Besides other well-known effects, it was recently demonstrated that EBV can induce significant modification in cell metabolism, which may lead or contribute to neoplastic transformation of human cells. Similarly, virus-induced tumorigenesis is characterized by relevant metabolic abnormalities directly induced by the oncoviruses. In this article, the authors critically review the most recent literature concerning EBV-induced metabolism alterations in lymphomas.

Free amino acid content and metabolic activities of setting and aborting soybean ovaries

International Nuclear Information System (INIS)

Ghiasi, H.; Paech, C.; Dybing, C.D.

1987-01-01

Fruits of soybean (glycine max [L.] Merr.) that are destined to abscise shortly after anthesis grow more slowly than fruits that will be retained. In this work, amino acid composition, protein metabolism, and nucleic acid metabolism were studied in setting and abscising soybean ovaries from anthesis to 6 days after anthesis. Principal free amino acids were asparagine, aspartic acid, glutamic acid, serine, and glutamine. Percent aspartate and glutamate declined as the ovaries grew, with aspartate declining more in abscising and glutamate more in setting ovaries. Percent glutamate was positively correlated to percent abscission throughout the period. Proline, serine, and leucine were positively correlated to abscission from 0 to 2 days after anthesis, whereas significant negative correlations were observed at these ages for ethanolamine and arginine. 75 Se fed as selenate and 14 C fed as sucrose, glycine, and alanine were readily incorporated into soluble and insoluble proteins in a 24-hour in vitro incubation. Radioactivity of total proteins, expressed on a per-ovary basis, was negatively correlated with percent abscission and positively correlated with ovary weight. [ 14 C]Glutamine and serine followed the opposite pattern, with greater protein labeling in abscising than in setting ovaries. When data were expressed as disintegrations per minute per milligram ovary fresh weight, protein labeling from alanine was seen to be significantly greater in abscising ovaries at anthesis and throughout the sampling period. Nucleic acid labeling from uridine was highly correlated to ovary weight; labeling from thymidine was greater in setting than abscising ovaries at anthesis and in abscising ovaries at later stages of development

Nontargeted LC–MS Metabolomics Approach for Metabolic Profiling of Plasma and Urine from Pigs Fed Branched Chain Amino Acids for Maximum Growth Performance

DEFF Research Database (Denmark)

Assadi Soumeh, Elham; Hedemann, Mette Skou; Poulsen, Hanne Damgaard

2016-01-01

The metabolic response in plasma and urine of pigs when feeding an optimum level of branched chain amino acids (BCAAs) for best growth performance is unknown. The objective of the current study was to identify the metabolic phenotype associated with the BCAAs intake level that could be linked to ...

A hepatic amino acid/mTOR/S6K-dependent signalling pathway modulates systemic lipid metabolism via neuronal signals.

Science.gov (United States)

Uno, Kenji; Yamada, Tetsuya; Ishigaki, Yasushi; Imai, Junta; Hasegawa, Yutaka; Sawada, Shojiro; Kaneko, Keizo; Ono, Hiraku; Asano, Tomoichiro; Oka, Yoshitomo; Katagiri, Hideki

2015-08-13

Metabolism is coordinated among tissues and organs via neuronal signals. Levels of circulating amino acids (AAs), which are elevated in obesity, activate the intracellular target of rapamycin complex-1 (mTORC1)/S6kinase (S6K) pathway in the liver. Here we demonstrate that hepatic AA/mTORC1/S6K signalling modulates systemic lipid metabolism via a mechanism involving neuronal inter-tissue communication. Hepatic expression of an AA transporter, SNAT2, activates the mTORC1/S6K pathway, and markedly elevates serum triglycerides (TGs), while downregulating adipose lipoprotein lipase (LPL). Hepatic Rheb or active-S6K expression have similar metabolic effects, whereas hepatic expression of dominant-negative-S6K inhibits TG elevation in SNAT2 mice. Denervation, pharmacological deafferentation and β-blocker administration suppress obesity-related hypertriglyceridemia with adipose LPL upregulation, suggesting that signals are transduced between liver and adipose tissue via a neuronal pathway consisting of afferent vagal and efferent sympathetic nerves. Thus, the neuronal mechanism uncovered here serves to coordinate amino acid and lipid levels and contributes to the development of obesity-related hypertriglyceridemia.

Effects of Lysine deficiency and Lys-Lys dipeptide on cellular apoptosis and amino acids metabolism.

Science.gov (United States)

Yin, Jie; Li, Yuying; Han, Hui; Zheng, Jie; Wang, Lijian; Ren, Wenkai; Chen, Shuai; Wu, Fei; Fang, Rejun; Huang, Xingguo; Li, Chunyong; Tan, Bie; Xiong, Xia; Zhang, Yuzhe; Liu, Gang; Yao, Jiming; Li, Tiejun; Yin, Yulong

2017-09-01

Lysine (Lys) is a common limiting amino acids (AA) for humans and animals and plays an important role in cell proliferation and metabolism, while metabolism of Lys deficiency and its dipeptide is still obscure. Thus, this study mainly investigated the effects of Lys deficiency and Lys-Lys dipeptide on apoptosis and AA metabolism in vitro and in vivo models. Lys deficiency induced cell-cycle arrest and apoptosis and upregulated Lys transporters in vitro and in vivo. SLC7A11, a cystine-glutamate antiporter, was markedly upregulated by Lys deficiency and then further mediated cystine uptake and glutamate release, which was negatively regulated by cystine and glutamate transporters. Meanwhile, Lys deprivation upregulated pept1 expression, which might improve Lys-Lys dipeptide absorption to compensate for the reduced Lys availability. Lys-Lys dipeptide alleviated Lys deficiency induced cell-cycle arrest and apoptosis and influenced AA metabolism. Furthermore, the mammalian target of rapamycin signal might be involved in sensing cellular Lys starvation and Lys-Lys dipeptide. Altogether, these studies suggest that Lys deficiency impairs AA metabolism and causes apoptosis. Lys-Lys dipeptide serves as a Lys source and alleviates Lys deficiency induced cellular imbalance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigations into the influence of airborne pollutants on the metabolism of secondary phenolic substances and amino acids. Untersuchungen ueber den Einfluss von Luftschadstoffen auf den Stoffwechsel von phenolischen Sekundaerstoffen und Aminosaeuren

Energy Technology Data Exchange (ETDEWEB)

Strack, D.

1988-10-01

Quantitative analyses of secondary phenols, free amino acids, and of the enzyme activities arginase and asparaginase were carried out on spruce needles from six different forest sites in North-Rhine Westphalia. In addition, the effects of ozone on spruce aged seven to eight years were investigated. The aim of this was to find out whether there is a correlation between the phenol and amino acid metabolism and the damage rate in older spruce (31 to 60 years) and in younger spruce exposed to ozone. No correlation could be established with a single exception: In one site, the free amino acid pattern showed a 10-fold increase of arginine and an accumulation of ornithine and lysine. This indicates a disturbed nitrogen metabolism, in particular a stimulation of the urea cycle, which may be caused by anthropogenic over fertilizing with nitrogen. The findings for the spruce exposed to ozone indicate a more complex effect on the needle metabolism, which affects both the phenol metabolism (strong decrease of the catechine concentration) and the amino acid metabolism (increase of the alanine concentration). This may be caused by damaged membranes (i.e. higher permeability accompanied by sensitive changes in the metabolic compartmenting) or by a potential increase of transaminase activities. (orig./MG).

Metabolic profiling of plasma amino acids shows that histidine increases following the consumption of pork

OpenAIRE

Samman S; Crossett B; Somers M; Bell KJ; Lai NT; Sullivan DR; Petocz P

2014-01-01

Samir Samman,1 Ben Crossett,2 Miles Somers,1 Kirstine J Bell,1 Nicole T Lai,1,3 David R Sullivan,3 Peter Petocz4 1Discipline of Nutrition and Metabolism, 2Discipline of Proteomics and Biotechnology, School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia; 3Department of Clinical Biochemistry, Royal Prince Alfred Hospital, Sydney, NSW, Australia; 4Department of Statistics, Macquarie University, Sydney, NSW, Australia Abstract: Amino acid (AA) status is determined by facto...

Carbon isotopic patterns of amino acids associated with various microbial metabolic pathways and physiological conditions

Science.gov (United States)

Wang, P. L.; Hsiao, K. T.; Lin, L. H.

2017-12-01

Amino acids represent one of the most important categories of biomolecule. Their abundance and isotopic patterns have been broadly used to address issues related to biochemical processes and elemental cycling in natural environments. Previous studies have shown that various carbon assimilative pathways of microorganisms (e.g. autotrophy, heterotrophy and acetotrophy) could be distinguished by carbon isotopic patterns of amino acids. However, the taxonomic and catabolic coverage are limited in previous examination. This study aims to uncover the carbon isotopic patterns of amino acids for microorganisms remaining uncharacterized but bearing biogeochemical and ecological significance in anoxic environments. To fulfill the purpose, two anaerobic strains were isolated from riverine wetland and mud volcano in Taiwan. One strain is a sulfate reducing bacterium (related to Desulfovibrio marrakechensis), which is capable of utilizing either H2 or lactate, and the other is a methanogen (related to Methanolobus profundi), which grows solely with methyl-group compounds. Carbon isotope analyses of amino acids were performed on cells grown in exponential and stationary phase. The isotopic patterns were similar for all examined cultures, showing successive 13C depletion along synthetic pathways. No significant difference was observed for the methanogen and lactate-utilizing sulfate reducer harvested in exponential and stationary phases. In contrast, the H2-utilizing sulfate reducer harvested in stationary phase depleted and enriched 13C in aspartic acid and glycine, respectively when compared with that harvested in exponential phase. Such variations might infer the change of carbon flux during synthesis of these two amino acids in the reverse TCA cycle. In addition, the discriminant function analysis for all available data from culture studies further attests the capability of using carbon isotope patterns of amino acids in identifying microbial metabolisms.

Metabolic engineering of Escherichia coli for the production of riboflavin

OpenAIRE

Lin, Zhenquan; Xu, Zhibo; Li, Yifan; Wang, Zhiwen; Chen, Tao; Zhao, Xueming

2014-01-01

Background Riboflavin (vitamin B2), the precursor of the flavin cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), is used commercially as an animal feed supplement and food colorant. E. coli is a robust host for various genetic manipulations and has been employed for efficient production of biofuels, polymers, amino acids, and bulk chemicals. Thus, the aim of this study was to understand the metabolic capacity of E. coli for the riboflavin production by modification...

Amino Acid Catabolism in Alzheimer’s Disease Brain: Friend or Foe?

Directory of Open Access Journals (Sweden)

Jeddidiah W. D. Griffin

2017-01-01

Full Text Available There is a dire need to discover new targets for Alzheimer’s disease (AD drug development. Decreased neuronal glucose metabolism that occurs in AD brain could play a central role in disease progression. Little is known about the compensatory neuronal changes that occur to attempt to maintain energy homeostasis. In this review using the PubMed literature database, we summarize evidence that amino acid oxidation can temporarily compensate for the decreased glucose metabolism, but eventually altered amino acid and amino acid catabolite levels likely lead to toxicities contributing to AD progression. Because amino acids are involved in so many cellular metabolic and signaling pathways, the effects of altered amino acid metabolism in AD brain are far-reaching. Possible pathological results from changes in the levels of several important amino acids are discussed. Urea cycle function may be induced in endothelial cells of AD patient brains, possibly to remove excess ammonia produced from increased amino acid catabolism. Studying AD from a metabolic perspective provides new insights into AD pathogenesis and may lead to the discovery of dietary metabolite supplements that can partially compensate for alterations of enzymatic function to delay AD or alleviate some of the suffering caused by the disease.

Amino Acid Crossword Puzzle

Science.gov (United States)

Sims, Paul A.

2011-01-01

Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

/sup 1/H-NMR urinalysis. Simultaneous screening of inborn errors of metabolism of amino acid and organic acid disorders

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Hideaki; Yamaguchi, Shuichi

1988-02-01

In an effort to examine the usefulness of /sup 1/H-nuclear magnetic resonance (NMR) urinalysis in the diagnosis of congenital metabolic disorders, 70 kinds of urinary metabolites were analysed in relation to the diagnosis of inborn errors of amino acid and organic acid disorders. Homogated decoupling (HMG) method failed to analyze six metabolites within the undetectable range. When non-decoupling method (NON), in which the materials are dissolved in dimethyl sulfoxide, was used, the identification of signals became possible. The combination of HMG and NON methods was, therefore, considered to identify all of the metabolites. When the urine samples, which were obtained from patients with hyperglycerolemia, hyperornithinemia, glutaric acidemia type II, or glycerol kinase deficiency, were analysed by using both HMG and NON methods, abnormally increased urinary metabolites were detected. /sup 1/H-NMR urinalysis, if used in the combination of HMG and NON methods, may allow simultanenous screening of inborn errors of metabolism of amino acid and organic acid disorders. (Namekawa, K.).

High-level production of C-11-carboxyl-labeled amino acids

International Nuclear Information System (INIS)

Washburn, L.C.; Sun, T.T.; Byrd, B.L.; Hayes, R.L.; Butler, T.A.; Callahan, A.P.

1979-01-01

Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two others for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period

Effect of specific amino acids on hepatic lipid metabolism in fructose-induced non-alcoholic fatty liver disease.

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Jegatheesan, Prasanthi; Beutheu, Stéphanie; Ventura, Gabrielle; Sarfati, Gilles; Nubret, Esther; Kapel, Nathalie; Waligora-Dupriet, Anne-Judith; Bergheim, Ina; Cynober, Luc; De-Bandt, Jean-Pascal

2016-02-01

Fructose diets have been shown to induce insulin resistance and to alter liver metabolism and gut barrier function, ultimately leading to non-alcoholic fatty liver disease. Citrulline, Glutamine and Arginine may improve insulin sensitivity and have beneficial effects on gut trophicity. Our aim was to evaluate their effects on liver and gut functions in a rat model of fructose-induced non-alcoholic fatty liver disease. Male Sprague-Dawley rats (n = 58) received a 4-week fructose (60%) diet or standard chow with or without Citrulline (0.15 g/d) or an isomolar amount of Arginine or Glutamine. All diets were made isonitrogenous by addition of non-essential amino acids. At week 4, nutritional and metabolic status (plasma glucose, insulin, cholesterol, triglycerides and amino acids, net intestinal absorption) was determined; steatosis (hepatic triglycerides content, histological examination) and hepatic function (plasma aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, bilirubin) were assessed; and gut barrier integrity (myeloperoxidase activity, portal endotoxemia, tight junction protein expression and localization) and intestinal and hepatic inflammation were evaluated. We also assessed diets effects on caecal microbiota. In these experimental isonitrogenous fructose diet conditions, fructose led to steatosis with dyslipidemia but without altering glucose homeostasis, liver function or gut permeability. Fructose significantly decreased Bifidobacterium and Lactobacillus and tended to increase endotoxemia. Arginine and Glutamine supplements were ineffective but Citrulline supplementation prevented hypertriglyceridemia and attenuated liver fat accumulation. While nitrogen supply alone can attenuate fructose-induced non-alcoholic fatty liver disease, Citrulline appears to act directly on hepatic lipid metabolism by partially preventing hypertriglyceridemia and steatosis. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition

Metabolism of organic acids, nitrogen and amino acids in chlorotic leaves of 'Honeycrisp' apple (Malus domestica Borkh) with excessive accumulation of carbohydrates.

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Wang, Huicong; Ma, Fangfang; Cheng, Lailiang

2010-07-01

Metabolite profiles and activities of key enzymes in the metabolism of organic acids, nitrogen and amino acids were compared between chlorotic leaves and normal leaves of 'Honeycrisp' apple to understand how accumulation of non-structural carbohydrates affects the metabolism of organic acids, nitrogen and amino acids. Excessive accumulation of non-structural carbohydrates and much lower CO(2) assimilation were found in chlorotic leaves than in normal leaves, confirming feedback inhibition of photosynthesis in chlorotic leaves. Dark respiration and activities of several key enzymes in glycolysis and tricarboxylic acid (TCA) cycle, ATP-phosphofructokinase, pyruvate kinase, citrate synthase, aconitase and isocitrate dehydrogenase were significantly higher in chlorotic leaves than in normal leaves. However, concentrations of most organic acids including phosphoenolpyruvate (PEP), pyruvate, oxaloacetate, 2-oxoglutarate, malate and fumarate, and activities of key enzymes involved in the anapleurotic pathway including PEP carboxylase, NAD-malate dehydrogenase and NAD-malic enzyme were significantly lower in chlorotic leaves than in normal leaves. Concentrations of soluble proteins and most free amino acids were significantly lower in chlorotic leaves than in normal leaves. Activities of key enzymes in nitrogen assimilation and amino acid synthesis, including nitrate reductase, glutamine synthetase, ferredoxin and NADH-dependent glutamate synthase, and glutamate pyruvate transaminase were significantly lower in chlorotic leaves than in normal leaves. It was concluded that, in response to excessive accumulation of non-structural carbohydrates, glycolysis and TCA cycle were up-regulated to "consume" the excess carbon available, whereas the anapleurotic pathway, nitrogen assimilation and amino acid synthesis were down-regulated to reduce the overall rate of amino acid and protein synthesis.

Metabonomics and its role in amino acid nutrition research.

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He, Qinghua; Yin, Yulong; Zhao, Feng; Kong, Xiangfeng; Wu, Guoyao; Ren, Pingping

2011-06-01

Metabonomics combines metabolic profiling and multivariate data analysis to facilitate the high-throughput analysis of metabolites in biological samples. This technique has been developed as a powerful analytical tool and hence has found successful widespread applications in many areas of bioscience. Metabonomics has also become an important part of systems biology. As a sensitive and powerful method, metabonomics can quantitatively measure subtle dynamic perturbations of metabolic pathways in organisms due to changes in pathophysiological, nutritional, and epigenetic states. Therefore, metabonomics holds great promise to enhance our understanding of the complex relationship between amino acids and metabolism to define the roles for dietary amino acids in maintaining health and the development of disease. Such a technique also aids in the studies of functions, metabolic regulation, safety, and individualized requirements of amino acids. Here, we highlight the common workflow of metabonomics and some of the applications to amino acid nutrition research to illustrate the great potential of this exciting new frontier in bioscience.

Amino acid sequence and posttranslational modifications of human factor VIIa from plasma and transfected baby hamster kidney cells

International Nuclear Information System (INIS)

Thim, L.; Bjoern, S.; Christensen, M.; Nicolaisen, E.M.; Lund-Hansen, T.; Pedersen, A.H.; Hedner, U.

1988-01-01

Blood coagulation factor VII is a vitamin K dependent glycoprotein which in its activated form, factor VII a , participates in the coagulation process by activating factor X and/or factor IX in the presence of Ca 2+ and tissue factor. Three types of potential posttranslational modifications exist in the human factor VII a molecule, namely, 10 γ-carboxylated, N-terminally located glutamic acid residues, 1 β-hydroxylated aspartic acid residue, and 2 N-glycosylated asparagine residues. In the present study, the amino acid sequence and posttranslational modifications of recombinant factor VII a as purified from the culture medium of a transfected baby hamster kidney cell line have been compared to human plasma factor VII a . By use of HPLC, amino acid analysis, peptide mapping, and automated Edman degradation, the protein backbone of recombinant factor VII a was found to be identical with human factor VII a . Asparagine residues 145 and 322 were found to be fully N-glycosylated in human plasma factor VII a . In the recombinant factor VII a , asparagine residue 322 was fully glycosylated whereas asparagine residue 145 was only partially (approximately 66%) glycosylated. Besides minor differences in the sialic acid and fucose contents, the overall carbohydrate compositions were nearly identical in recombinant factor VII a and human plasma factor VII a . These results show that factor VII a as produced in the transfected baby hamster kidney cells is very similar to human plasma factor VII a and that this cell line thus might represent an alternative source for human factor VII a

Perturbations of Amino Acid Metabolism Associated with Glyphosate-Dependent Inhibition of Shikimic Acid Metabolism Affect Cellular Redox Homeostasis and Alter the Abundance of Proteins Involved in Photosynthesis and Photorespiration1[W][OA

Science.gov (United States)

Vivancos, Pedro Diaz; Driscoll, Simon P.; Bulman, Christopher A.; Ying, Liu; Emami, Kaveh; Treumann, Achim; Mauve, Caroline; Noctor, Graham; Foyer, Christine H.

2011-01-01

The herbicide glyphosate inhibits the shikimate pathway of the synthesis of amino acids such as phenylalanine, tyrosine, and tryptophan. However, much uncertainty remains concerning precisely how glyphosate kills plants or affects cellular redox homeostasis and related processes in glyphosate-sensitive and glyphosate-resistant crop plants. To address this issue, we performed an integrated study of photosynthesis, leaf proteomes, amino acid profiles, and redox profiles in the glyphosate-sensitive soybean (Glycine max) genotype PAN809 and glyphosate-resistant Roundup Ready Soybean (RRS). RRS leaves accumulated much more glyphosate than the sensitive line but showed relatively few changes in amino acid metabolism. Photosynthesis was unaffected by glyphosate in RRS leaves, but decreased abundance of photosynthesis/photorespiratory pathway proteins was observed together with oxidation of major redox pools. While treatment of a sensitive genotype with glyphosate rapidly inhibited photosynthesis and triggered the appearance of a nitrogen-rich amino acid profile, there was no evidence of oxidation of the redox pools. There was, however, an increase in starvation-associated and defense proteins. We conclude that glyphosate-dependent inhibition of soybean leaf metabolism leads to the induction of defense proteins without sustained oxidation. Conversely, the accumulation of high levels of glyphosate in RRS enhances cellular oxidation, possibly through mechanisms involving stimulation of the photorespiratory pathway. PMID:21757634

Seed and Foliar Application of Amino Acids Improve Variables of Nitrogen Metabolism and Productivity in Soybean Crop.

Science.gov (United States)

Teixeira, Walquíria F; Fagan, Evandro B; Soares, Luis H; Soares, Jérssica N; Reichardt, Klaus; Neto, Durval D

2018-01-01

The application of amino acids in crops has been a common practice in recent years, although most of the time they are associated with products based on algae extracts or on fermented animal or vegetable wastes. However, little is known about the isolated effect of amino acids on the development of crops. Therefore, the objective of this research was to evaluate the effect of the application of isolated amino acids on the in some steps of the soybean nitrogen metabolism and on productivity. Experiments were carried out in a greenhouse and in the field with the application of the amino acids glutamate (Glu), phenylalanine (Phe), cysteine (Cys) and glycine (Gly) and as a set (Glu+Phe+Cys+Gly), as seed treatment (ST), as foliar application (FA) and both (ST+FA), at the V 4 growth stage. Evaluations consisted of nitrate reductase and urease activities, nitrate, ureide, total amino acids and total nitrogen content in leaves, and productivity. The application of Glu to leaves, Cys as ST and a mixture of Glu+Cys+Phe+Gly as ST+FA in the greenhouse experiment increased the total amino acids content. In the field experiment all treatments increased the amino acid content in leaves. At the V 6 stage in the field experiment, all modes of Gly application, Glu as ST and FA, Cys and Phe as ST+FA and Glu+Cys+Phe+Gly as FA increased the nitrate content in leaves. In the greenhouse, application of Cys and Phe as ST increased the production of soybean plants by at least 21%. The isolated application of Cys, Phe, Gly, Glu and the set of these amino acids as ST increased the productivity of soybean plants in the field experiment by at least 22%.

Seed and Foliar Application of Amino Acids Improve Variables of Nitrogen Metabolism and Productivity in Soybean Crop

Science.gov (United States)

Teixeira, Walquíria F.; Fagan, Evandro B.; Soares, Luis H.; Soares, Jérssica N.; Reichardt, Klaus; Neto, Durval D.

2018-01-01

The application of amino acids in crops has been a common practice in recent years, although most of the time they are associated with products based on algae extracts or on fermented animal or vegetable wastes. However, little is known about the isolated effect of amino acids on the development of crops. Therefore, the objective of this research was to evaluate the effect of the application of isolated amino acids on the in some steps of the soybean nitrogen metabolism and on productivity. Experiments were carried out in a greenhouse and in the field with the application of the amino acids glutamate (Glu), phenylalanine (Phe), cysteine (Cys) and glycine (Gly) and as a set (Glu+Phe+Cys+Gly), as seed treatment (ST), as foliar application (FA) and both (ST+FA), at the V4 growth stage. Evaluations consisted of nitrate reductase and urease activities, nitrate, ureide, total amino acids and total nitrogen content in leaves, and productivity. The application of Glu to leaves, Cys as ST and a mixture of Glu+Cys+Phe+Gly as ST+FA in the greenhouse experiment increased the total amino acids content. In the field experiment all treatments increased the amino acid content in leaves. At the V6 stage in the field experiment, all modes of Gly application, Glu as ST and FA, Cys and Phe as ST+FA and Glu+Cys+Phe+Gly as FA increased the nitrate content in leaves. In the greenhouse, application of Cys and Phe as ST increased the production of soybean plants by at least 21%. The isolated application of Cys, Phe, Gly, Glu and the set of these amino acids as ST increased the productivity of soybean plants in the field experiment by at least 22%. PMID:29643860

The cerebral metabolism of amino acids and related metabolites as studied by {sup 13}C and {sup 14}C labelling

Energy Technology Data Exchange (ETDEWEB)

Hassel, B

1995-11-01

The present investigations show the feasibility of analyzing the cerebral metabolism of amino acids and related metabolites by {sup 13}C-and {sup 14}C-labelling using labelled acetate and glucose as markers for glial and neuronal metabolism, respectively. Using [{sup 13}C]acetate, it was shown that glial cells export {approx}60% of their TCA cycle intermediates, mostly as glutamine, and that this glutamine is used by neurons partly as an energy reserve, and partly it is converted directly to glutamate and GABA. Using [{sup 13}C]glucose, the glial process or pyruvate carboxylation was shown to compensate fully for the loss of glutamine. The mechanism of action of two neurotoxins, fluorocitrate and 3-nitropropionate was elucidated. The latter toxin was shown to inhibit the TCA cycle of GABAergic neurons selectively. Formation of pyruvate and lactate from glial TCA cycle intermediates was demonstrated in vivo. This pathway may be important for glial inactivation of transmitter glutamate and GABA. The results illustrate glianeuronal interactions, and they suggest the applicability of {sup 13}CNMR spectroscopy to the detailed study of the cerebral metabolism of amino acids in the intact, unanesthetized human brain. 174 refs.

Nitrogen and amino acid metabolism in dairy cows

NARCIS (Netherlands)

Tamminga, S.

1981-01-01

For the process of milk production, the dairy cow requires nutrients of which energy supplying nutrients and protein or amino acid supplying nutrients are the most important. Amino acid supplying nutrients have to be absorbed from the small intestine and the research reported in this thesis mainly

Simultaneous analysis of amino acid and organic acid by NMR spectrometry, 2. Diagnostic aids for inborn error of metabolism

Energy Technology Data Exchange (ETDEWEB)

Koda, Naoya; Yamaguchi, Shuichi; Mori, Takeshi.

1987-09-01

Analysis of urine from patients with inborn error of metabolism were studied by /sup 1/H-nuclear magnetic resonance (NMR) spectrometry. Diseases studied were as follows; phenylketonuria, biotin responsive multiple carboxylase deficiency, non-ketotic hyperglycinemia, 3-ketothiolase deficiency, alkaptonuria, methylmalonic acidemia, isovaleric acidemia, glutaric aciduria, argininosuccinic aciduria and hyperornithinemia. In each disease, specific metabolites in urine were recognized by NMR spectrometry. This method is accomplished within 10 minutes with non-treated small volume of urine and will be successfully available for the screening andor diagnosis of inherited metabolic diseases of amino acid and organic acid.

Functional Modification of Thioether Groups in Peptides, Polypeptides, and Proteins.

Science.gov (United States)

Deming, Timothy J

2017-03-15

Recent developments in the modification of methionine and other thioether-containing residues in peptides, polypeptides, and proteins are reviewed. Properties and potential applications of the resulting functionalized products are also discussed. While much of this work is focused on natural Met residues, modifications at other side-chain residues have also emerged as new thioether-containing amino acids have been incorporated into peptidic materials. Functional modification of thioether-containing amino acids has many advantages and is a complementary methodology to the widely utilized methods for modification at cysteine residues.

Effect of alternative pathway therapy on branched chain amino acid metabolism in urea cycle disorder patients.

Science.gov (United States)

Scaglia, Fernando; Carter, Susan; O'Brien, William E; Lee, Brendan

2004-04-01

Urea cycle disorders (UCDs) are a group of inborn errors of hepatic metabolism caused by the loss of enzymatic activities that mediate the transfer of nitrogen from ammonia to urea. These disorders often result in life-threatening hyperammonemia and hyperglutaminemia. A combination of sodium phenylbutyrate and sodium phenylacetate/benzoate is used in the clinical management of children with urea cycle defects as a glutamine trap, diverting nitrogen from urea synthesis to alternatives routes of excretion. We have observed that patients treated with these compounds have selective branched chain amino acid (BCAA) deficiency despite adequate dietary protein intake. However, the direct effect of alternative therapy on the steady state levels of plasma branched chain amino acids has not been well characterized. We have measured steady state plasma branched chain and other essential non-branched chain amino acids in control subjects, untreated ornithine transcarbamylase deficiency females and treated null activity urea cycle disorder patients in the fed steady state during the course of stable isotope studies. Steady-state leucine levels were noted to be significantly lower in treated urea cycle disorder patients when compared to either untreated ornithine transcarbamylase deficiency females or control subjects (Purea cycle disorder patients. These findings suggest that better titration of protein restriction could be achieved with branched chain amino acid supplementation in patients with UCDs who are on alternative route therapy.

Formation of taste-active amino acids, amino acid derivatives and peptides in food fermentations - A review.

Science.gov (United States)

Zhao, Cindy J; Schieber, Andreas; Gänzle, Michael G

2016-11-01

Fermented foods are valued for their rich and complex odour and taste. The metabolic activity of food-fermenting microorganisms determines food quality and generates odour and taste compounds. This communication reviews the formation of taste-active amino acids, amino acid derivatives and peptides in food fermentations. Pathways of the generation of taste compounds are presented for soy sauce, cheese, fermented meats, and bread. Proteolysis or autolysis during food fermentations generates taste-active amino acids and peptides; peptides derived from proteolysis particularly impart umami taste (e.g. α-glutamyl peptides) or bitter taste (e.g. hydrophobic peptides containing proline). Taste active peptide derivatives include pyroglutamyl peptides, γ-glutamyl peptides, and succinyl- or lactoyl amino acids. The influence of fermentation microbiota on proteolysis, and peptide hydrolysis, and the metabolism of glutamate and arginine is well understood, however, the understanding of microbial metabolic activities related to the formation of taste-active peptide derivatives is incomplete. Improved knowledge of the interactions between taste-active compounds will enable the development of novel fermentation strategies to develop tastier, less bitter, and low-salt food products, and may provide novel and "clean label" ingredients to improve the taste of other food products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Yuanhuapine-induced intestinal and hepatotoxicity were correlated with disturbance of amino acids, lipids, carbohydrate metabolism and gut microflora function: A rat urine metabonomic study.

Science.gov (United States)

Chen, Yanyan; Duan, Jin-Ao; Guo, Jianming; Shang, Erxin; Tang, Yuping; Qian, Yefei; Tao, Weiwei; Liu, Pei

2016-07-15

This research was designed to study metabonomic characteristics of the toxicity induced by yuanhuapine, a major bioactive diterpenoid in a well-known traditional Chinese medicine-Genkwa Flos. General observation, blood biochemistry and histopathological examination were used to reflect yuanhuapine-induced toxicity. Urine samples from rats in control and yuanhuapine treated rats were analyzed by ultra-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Pattern recognition methods including principal components analysis (PCA), partial least-squared discriminant analysis (PLS-DA), orthogonal partial least-squared discriminant analysis (OPLS-DA) and computational system analysis were integrated to obtain comprehensive metabonomic profiling and pathways of the biological data sets. The results suggested that yuanhuapine could induce intestinal and liver damage. And 14 endogenous metabolites as biomarkers related to the amino acids metabolism, lipids metabolism, carbohydrate metabolism and gut microflora were significantly changed in the urine of yuanhuapine treated rats, which were firstly constructed the metabolomic feature profiling and metabolite interaction network of yuanhuapine-induced injury using pattern recognition methods and Ingenuity Pathway Analysis (IPA) approach. The present study showed that yuanhuapine-induced intestinal and hepatic toxicity were correlated with disturbance of amino acids metabolism, lipids metabolism, carbohydrate metabolism and gut microflora. Copyright © 2015 Elsevier B.V. All rights reserved.

Sex Differences in Energy Metabolism Need to Be Considered with Lifestyle Modifications in Humans

Directory of Open Access Journals (Sweden)

Betty N. Wu

2011-01-01

Full Text Available Women have a higher proportion of body fat compared to men. However, women consume fewer kilojoules per kilogram lean mass and burn fat more preferentially during exercise compared with men. During gestation, women store even greater amounts of fat that cannot be solely attributed to increased energy intake. These observations suggest that the relationship between kilojoules consumed and kilojoules utilised is different in men and women. The reason for these sex differences in energy metabolism is not known; however, it may relate to sex steroids, differences in insulin resistance, or metabolic effects of other hormones such as leptin. When considering lifestyle modifications, sex differences in energy metabolism should be considered. Moreover, elucidating the regulatory role of hormones in energy homeostasis is important for understanding the pathogenesis of obesity and perhaps in the future may lead to ways to reduce body fat with less energy restriction.

Amino acid regulation of autophagosome formation

NARCIS (Netherlands)

Meijer, Alfred J.

2008-01-01

Amino acids are not only substrates for various metabolic pathways, but can also serve as signaling molecules controlling signal transduction pathways. One of these signaling pathways is mTOR-dependent and is activated by amino acids (leucine in particular) in synergy with insulin. Activation of

Inflammation and ER Stress Regulate Branched-Chain Amino Acid Uptake and Metabolism in Adipocytes

Science.gov (United States)

Burrill, Joel S.; Long, Eric K.; Reilly, Brian; Deng, Yingfeng; Armitage, Ian M.; Scherer, Philipp E.

2015-01-01

Inflammation plays a critical role in the pathology of obesity-linked insulin resistance and is mechanistically linked to the effects of macrophage-derived cytokines on adipocyte energy metabolism, particularly that of the mitochondrial branched-chain amino acid (BCAA) and tricarboxylic acid (TCA) pathways. To address the role of inflammation on energy metabolism in adipocytes, we used high fat-fed C57BL/6J mice and lean controls and measured the down-regulation of genes linked to BCAA and TCA cycle metabolism selectively in visceral but not in subcutaneous adipose tissue, brown fat, liver, or muscle. Using 3T3-L1 cells, TNFα, and other proinflammatory cytokine treatments reduced the expression of the genes linked to BCAA transport and oxidation. Consistent with this, [14C]-leucine uptake and conversion to triglycerides was markedly attenuated in TNFα-treated adipocytes, whereas the conversion to protein was relatively unaffected. Because inflammatory cytokines lead to the induction of endoplasmic reticulum stress, we evaluated the effects of tunicamycin or thapsigargin treatment of 3T3-L1 cells and measured a similar down-regulation in the BCAA/TCA cycle pathway. Moreover, transgenic mice overexpressing X-box binding protein 1 in adipocytes similarly down-regulated genes of BCAA and TCA metabolism in vivo. These results indicate that inflammation and endoplasmic reticulum stress attenuate lipogenesis in visceral adipose depots by down-regulating the BCAA/TCA metabolism pathway and are consistent with a model whereby the accumulation of serum BCAA in the obese insulin-resistant state is linked to adipose inflammation. PMID:25635940

Elevated Metabolites of Steroidogenesis and Amino Acid Metabolism in Preadolescent Female Children With High Urinary Bisphenol A Levels: A High-Resolution Metabolomics Study.

Science.gov (United States)

Khan, Adnan; Park, Hyesook; Lee, Hye Ah; Park, Bohyun; Gwak, Hye Sun; Lee, Hye-Ra; Jee, Sun Ha; Park, Youngja H

2017-12-01

Health risks associated with bisphenol A (BPA) exposure are controversially highlighted by numerous studies. High-resolution metabolomics (HRM) can confirm these proposed associations and may provide a mechanistic insight into the connections between BPA exposure and metabolic perturbations. This study was aimed to identify the changes in metabolomics profile due to BPA exposure in urine and serum samples collected from female and male children (n = 18) aged 7-9. Urine was measured for BPA concentration, and the children were subsequently classified into high and low BPA groups. HRM, coupled with Liquid chromatography-mass spectrometry/MS, followed by multivariate statistical analysis using MetaboAnalyst 3.0, were performed on urine to discriminate metabolic profiles between high and low BPA children as well as males and females, followed by further validation of our findings in serum samples obtained from same population. Metabolic pathway analysis showed that biosynthesis of steroid hormones and 7 other pathways-amino acid and nucleotide biosynthesis, phenylalanine metabolism, tryptophan metabolism, tyrosine metabolism, lysine degradation, pyruvate metabolism, and arginine biosynthesis-were affected in high BPA children. Elevated levels of metabolites associated with these pathways in urine and serum were mainly observed in female children, while these changes were negligible in male children. Our results suggest that the steroidogenesis pathway and amino acid metabolism are the main targets of perturbation by BPA in preadolescent girls. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Plasma free amino acid kinetics in rainbow trout (Oncorhynchus mykiss) using a bolus injection of 15N-labeled amino acids.

Science.gov (United States)

Robinson, Jacob William; Yanke, Dan; Mirza, Jeff; Ballantyne, James Stuart

2011-02-01

To gain insight into the metabolic design of the amino acid carrier systems in fish, we injected a bolus of (15)N amino acids into the dorsal aorta in mature rainbow trout (Oncorhynchus mykiss). The plasma kinetic parameters including concentration, pool size, rate of disappearance (R(d)), half-life and turnover rate were determined for 15 amino acids. When corrected for metabolic rate, the R(d) values obtained for trout for most amino acids were largely comparable to human values, with the exception of glutamine (which was lower) and threonine (which was higher). R(d) values ranged from 0.9 μmol 100 g(-1) h(-1) (lysine) to 22.1 μmol 100 g(-1) h(-1) (threonine) with most values falling between 2 and 6 μmol 100 g(-1) h(-1). There was a significant correlation between R(d) and the molar proportion of amino acids in rainbow trout whole body protein hydrolysate. Other kinetic parameters did not correlate significantly with whole body amino acid composition. This indicates that an important design feature of the plasma-free amino acids system involves proportional delivery of amino acids to tissues for protein synthesis.

A randomized controlled trial: branched-chain amino acid levels and glucose metabolism in patients with obesity and sleep apnea.

Science.gov (United States)

Barceló, Antonia; Morell-Garcia, Daniel; Salord, Neus; Esquinas, Cristina; Pérez, Gerardo; Pérez, Antonio; Monasterio, Carmen; Gasa, Merce; Fortuna, Ana Maria; Montserrat, Josep Maria; Mayos, Mercedes

2017-12-01

There is evidence that changes in branched-chain amino acid (BCAA) levels may correlate with the efficacy of therapeutic interventions for affecting improvement in metabolic control. The objective of this study was to evaluate whether serum concentrations of BCAAs (leucine, isoleucine, valine) could mediate in insulin sensitivity and glucose tolerance after continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA). A prospective randomized controlled trial of OSA patients with morbid obesity was conducted. Eighty patients were randomized into two groups: 38 received conservative treatment and 42 received CPAP treatment for 12 weeks. Plasma levels of BCAA, glucose tolerance and insulin resistance were evaluated at baseline and after treatment. After treatment, significant decreases of leucine levels were observed in both groups when compared with baseline levels (P fasting plasma glucose and glycosylated haemoglobin values only in the conservative group (P < 0.05). In summary, we found that the treatment with CPAP for 12 weeks caused similar changes in circulating BCAAs concentrations to conservative treatment and a differential metabolic response of CPAP and conservative treatment was observed between the relationship of BCAAs and glucose homeostasis. Additional studies are needed to determine the interplay between branched-chain amino acids and glucose metabolism in patients with sleep apnea. © 2017 European Sleep Research Society.

Cationic amino acid uptake constitutes a metabolic regulation mechanism and occurs in the flagellar pocket of Trypanosoma cruzi.

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Mariana R Miranda

Full Text Available Trypanosomatids' amino acid permeases are key proteins in parasite metabolism since they participate in the adaptation of parasites to different environments. Here, we report that TcAAP3, a member of a Trypanosoma cruzi multigene family of permeases, is a bona fide arginine transporter. Most higher eukaryotic cells incorporate cationic amino acids through a single transporter. In contrast, T. cruzi can recognize and transport cationic amino acids by mono-specific permeases since a 100-fold molar excess of lysine could not affect the arginine transport in parasites that over-express the arginine permease (TcAAP3 epimastigotes. In order to test if the permease activity regulates downstream processes of the arginine metabolism, the expression of the single T. cruzi enzyme that uses arginine as substrate, arginine kinase, was evaluated in TcAAP3 epimastigotes. In this parasite model, intracellular arginine concentration increases 4-folds and ATP level remains constant until cultures reach the stationary phase of growth, with decreases of about 6-folds in respect to the controls. Interestingly, Western Blot analysis demonstrated that arginine kinase is significantly down-regulated during the stationary phase of growth in TcAAP3 epimastigotes. This decrease could represent a compensatory mechanism for the increase in ATP consumption as a consequence of the displacement of the reaction equilibrium of arginine kinase, when the intracellular arginine concentration augments and the glucose from the medium is exhausted. Using immunofluorescence techniques we also determined that TcAAP3 and the specific lysine transporter TcAAP7 co-localize in a specialized region of the plasma membrane named flagellar pocket, staining a single locus close to the flagellar pocket collar. Taken together these data suggest that arginine transport is closely related to arginine metabolism and cell energy balance. The clinical relevance of studying trypanosomatids' permeases

Plant amino acid-derived vitamins: biosynthesis and function.

Science.gov (United States)

Miret, Javier A; Munné-Bosch, Sergi

2014-04-01

Vitamins are essential organic compounds for humans, having lost the ability to de novo synthesize them. Hence, they represent dietary requirements, which are covered by plants as the main dietary source of most vitamins (through food or livestock's feed). Most vitamins synthesized by plants present amino acids as precursors (B1, B2, B3, B5, B7, B9 and E) and are therefore linked to plant nitrogen metabolism. Amino acids play different roles in their biosynthesis and metabolism, either incorporated into the backbone of the vitamin or as amino, sulfur or one-carbon group donors. There is a high natural variation in vitamin contents in crops and its exploitation through breeding, metabolic engineering and agronomic practices can enhance their nutritional quality. While the underlying biochemical roles of vitamins as cosubstrates or cofactors are usually common for most eukaryotes, the impact of vitamins B and E in metabolism and physiology can be quite different on plants and animals. Here, we first aim at giving an overview of the biosynthesis of amino acid-derived vitamins in plants, with a particular focus on how this knowledge can be exploited to increase vitamin contents in crops. Second, we will focus on the functions of these vitamins in both plants and animals (and humans in particular), to unravel common and specific roles for vitamins in evolutionary distant organisms, in which these amino acid-derived vitamins play, however, an essential role.

Artificial Metalloenzymes through Chemical Modification of Engineered Host Proteins

KAUST Repository

Zernickel, Anna

2014-10-01

With a few exceptions, all organisms are restricted to the 20 canonical amino acids for ribosomal protein biosynthesis. Addition of new amino acids to the genetic code can introduce novel functionalities to proteins, broadening the diversity of biochemical as well as chemical reactions and providing new tools to study protein structure, reactivity, dynamics and protein-protein-interactions. The site directed in vivo incorporation developed by P. G. SCHULTZ and coworkers, using an archeal orthogonal tRNA/aaRS (aminoacyl-tRNA synthase) pair, allows site-specifically insertion of a synthetic unnatural amino acid (UAA) by reprogramming the amber TAG stop codon. A variety of over 80 different UAAs can be introduced by this technique. However by now a very limited number can form kinetically stable bonds to late transition metals. This thesis aims to develop new catalytically active unnatural amino acids or strategies for a posttranslational modification of site-specific amino acids in order to achieve highly enantioselective metallorganic enzyme hybrids (MOEH). As a requirement a stable protein host has to be established, surviving the conditions for incorporation, posttranslational modification and the final catalytic reactions. mTFP* a fluorescent protein was genetically modified by excluding any exposed Cys, His and Met forming a variant mTFP*, which fulfills the required specifications. Posttranslational chemical modification of mTFP* allow the introduction of single site metal chelating moieties. For modification on exposed cysteines different maleiimid containing ligand structures were synthesized. In order to perform copper catalyzed click reactions, suitable unnatural amino acids (para-azido-(L)-phenylalanine, para-ethynyl-(L)-phenylalanine) were synthesized and a non-cytotoxic protocol was established. The triazole ring formed during this reaction may contribute as a moderate σ-donor/π-acceptor ligand to the metal binding site. Since the cell limits the

Treatment of Amino Acid Metabolism Disorders

Science.gov (United States)

... of amino acids. Babies with TYR I may need vitamin D, a vitamin that can help babies who ... Rickets is a condition in which too little vitamin D causes a child’s bones to be ... condition, he may need to take certain medicines. For example: Babies with ...

Novel method for chemical modification and patterning of the SU-8 photoresist

DEFF Research Database (Denmark)

Blagoi, Gabriela; Keller, Stephan Urs; Boisen, Anja

2007-01-01

the wetting behaviour of SU-8. The resolution limit of the AQ photopatterning method was 20 μm when using an uncollimated light source. AQ modification followed by a reaction with amino groups of Alexa-647 cadaverine and a Biotin-amino derivative proved possible modification and patterning of polymeric...

Specific Labeling of Zinc Finger Proteins using Non-canonical Amino Acids and Copper-free Click Chemistry

Science.gov (United States)

Kim, Younghoon; Kim, Sung Hoon; Ferracane, Dean; Katzenellenbogen, John A.

2012-01-01

Zinc finger proteins (ZFPs) play a key role in transcriptional regulation and serve as invaluable tools for gene modification and genetic engineering. Development of efficient strategies for labeling metalloproteins such as ZFPs is essential for understanding and controlling biological processes. In this work, we engineered ZFPs containing cysteine-histidine (Cys2-His2) motifs by metabolic incorporation of the unnatural amino acid azidohomoalanine (AHA), followed by specific protein labeling via click chemistry. We show that cyclooctyne promoted [3 + 2] dipolar cycloaddition with azides, known as copper-free click chemistry, provides rapid and specific labeling of ZFPs at high yields as determined by mass spectrometry analysis. We observe that the DNA-binding activity of ZFPs labeled by conventional copper-mediated click chemistry was completely abolished, whereas ZFPs labeled by copper-free click chemistry retain their sequence-specific DNA-binding activity under native conditions, as determined by electrophoretic mobility shift assays, protein microarrays and kinetic binding assays based on Förster resonance energy transfer (FRET). Our work provides a general framework to label metalloproteins such as ZFPs by metabolic incorporation of unnatural amino acids followed by copper-free click chemistry. PMID:22871171

A Branched-Chain Amino Acid-Related Metabolic Signature Characterizes Obese Adolescents with Non-Alcoholic Fatty Liver Disease

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Martina Goffredo

2017-06-01

Full Text Available Dysregulation of several metabolite pathways, including branched-chain amino acids (BCAAs, are associated with Non-Alcoholic Fatty Liver Disease (NAFLD and insulin resistance in adults, while studies in youth reported conflicting results. We explored whether, independently of obesity and insulin resistance, obese adolescents with NAFLD display a metabolomic signature consistent with disturbances in amino acid and lipid metabolism. A total of 180 plasma metabolites were measured by a targeted metabolomic approach in 78 obese adolescents with (n = 30 or without (n = 48 NAFLD assessed by magnetic resonance imaging (MRI. All subjects underwent an oral glucose tolerance test and subsets of patients underwent a two-step hyperinsulinemic-euglycemic clamp and/or a second MRI after a 2.2 ± 0.8-year follow-up. Adolescents with NAFLD had higher plasma levels of valine (p = 0.02, isoleucine (p = 0.03, tryptophan (p = 0.02, and lysine (p = 0.02 after adjustment for confounding factors. Circulating BCAAs were negatively correlated with peripheral and hepatic insulin sensitivity. Furthermore, higher baseline valine levels predicted an increase in hepatic fat content (HFF at follow-up (p = 0.01. These results indicate that a dysregulation of BCAA metabolism characterizes obese adolescents with NAFLD independently of obesity and insulin resistance and predict an increase in hepatic fat content over time.

Effects of dietary substitution of mixed amino acids for glucose on the splanchnic metabolism of plasma triglycerides, cholesterol, carbohydrates, and amino acids in conscious fed baboons.

Science.gov (United States)

Wolfe, B M; Redinger, R N; Marliss, E B; Grace, D M

1983-04-01

Splanchnic metabolism was studied in the fed state during prolonged constant intravenous administration of tracer amounts of [9,10]-3H palmitic acid and the calculated isocaloric intraduodenal administration (13 mg/min X kg body wt0.75) of either (1) glucose, (2) 15% mixed amino acids and 85% glucose or (3) 45% mixed amino acids and 55% glucose to conscious, restrained female baboons that had been maintained on a similar diet (supplemented in essential nutrients) for the previous 9 days. Secretion of plasma triglycerides from the splanchnic region was quantified from splanchnic flow and radiochemical measurements of transsplanchnic gradients of 3H-labeled free fatty acids and triglycerides. Mean splanchnic secretion of plasma triglycerides increased significantly as the proportion of dietary calories derived from amino acids was varied from 0 to 15 to 45% (mean values 1.1 +/- 0.1, 2.6 +/- 0.2 and 4.2 +/- 0.3 mumol/min kg body wt0.75, respectively, p less than 0.05). Increased triglyceride secretion was attributable to both significantly higher rates of esterification of free fatty acids taken up in the splanchnic region to triglycerides released into hepatic venous blood plasma (mean values 10 +/- 1, 16 +/- 2 and 34 +/- 5%, respectively) and to significantly higher rates of secretion of triglycerides derived from precursors other than free fatty acids. Higher intake of amino acids was also associated with both higher plasma concentrations of cholesterol and higher values for hepatic oxidation of cholesterol to bile acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Application of stable isotope tracer methods to studies of amino acid, protein, and energy metabolism in malnourished populations of developing countries. Report of an IAEA consultants' meeting held in Vienna, Austria, 14-16 December 1992

International Nuclear Information System (INIS)

1993-01-01

A Consultants' Meeting convened by the IAEA in December 1992, made recommendations on the organization of a Co-ordinated Research Programme (CRP) using stable isotopic techniques for international comparative studies of amino acid, protein, and energy metabolism in chronically undernourished people. The CRP will use recent developments in stable isotope tracer techniques ( 13 C and 15 N) to assess the impact of infection in undernourished people on the kinetics of protein breakdown, protein synthesis, amino acid metabolism, and on the synthetic rates of selected plasma proteins. Studies will be conducted in developing countries, particularly in young children. The programme goals are to (i) elaborate methods and model protocols which can be implemented in developing countries to investigate the impact on protein metabolism of infection superimposed on chronic undernutrition; (ii) test they hypothesis that dietary requirements for protein and amino acids are related to the place of nutrition and are altered substantially when infection is superimposed on chronic undernutrition. When feasible, the primary focus on protein/amino acid metabolism will be extended to assessments of protein/energy interactions when H 2 18 O becomes more readily available and/or at research sites with indirect calorimetry equipment. The data generated should be appropriate as a basis for reevaluating amino acid/protein requirements in these populations. Refs

New insights into sulfur amino acids function in gut health and disease

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The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acids (SAAs) metabolism in the body. Aside from their role in protein synthesis, methionine and cysteine are involved in many biological functions and diseases. Methionine (MET) is an indispensable amino acid and is...

Proteomic Investigation of Protein Profile Changes and Amino Acid Residue Level Modification in Cooked Lamb Meat: The Effect of Boiling.

Science.gov (United States)

Yu, Tzer-Yang; Morton, James D; Clerens, Stefan; Dyer, Jolon M

2015-10-21

Hydrothermal treatment (heating in water) is a common method of general food processing and preparation. For red-meat-based foods, boiling is common; however, how the molecular level effects of this treatment correlate to the overall food properties is not yet well-understood. The effects of differing boiling times on lamb meat and the resultant cooking water were here examined through proteomic evaluation. The longer boiling time was found to result in increased protein aggregation involving particularly proteins such as glyceraldehyde-3-phosphate dehydrogenase, as well as truncation in proteins such as in α-actinin-2. Heat-induced protein backbone cleavage was observed adjacent to aspartic acid and asparagine residues. Side-chain modifications of amino acid residues resulting from the heating, including oxidation of phenylalanine and formation of carboxyethyllysine, were characterized in the cooked samples. Actin and myoglobin bands from the cooked meat per se remained visible on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, even after significant cooking time. These proteins were also found to be the major source of observed heat-induced modifications. This study provides new insights into molecular-level modifications occurring in lamb meat proteins during boiling and a protein chemistry basis for better understanding the effect of this common treatment on the nutritional and functional properties of red-meat-based foods.

Enhanced productivity of gamma-amino butyric acid by cascade modifications of a whole-cell biocatalyst.

Science.gov (United States)

Yang, Xinwei; Ke, Chongrong; Zhu, Jiangming; Wang, Yan; Zeng, Wenchao; Huang, Jianzhong

2018-04-01

We previously developed a gamma-amino butyric acid (GABA)-producing strain of Escherichia coli, leading to production of 614.15 g/L GABA at 45 °C from L-glutamic acid (L-Glu) with a productivity of 40.94 g/L/h by three successive whole-cell conversion cycles. However, the increase in pH caused by the accumulation of GABA resulted in inactivation of the biocatalyst and consequently led to relatively lower productivity. In this study, by overcoming the major problem associated with the increase in pH during the production process, a more efficient biocatalyst was obtained through cascade modifications of the previously reported E. coli strain. First, we introduced four amino acid mutations to the codon-optimized GadB protein from Lactococcus lactis to shift its decarboxylation activity toward a neutral pH, resulting in 306.65 g/L of GABA with 99.14 mol% conversion yield and 69.8% increase in GABA productivity. Second, we promoted transportation of L-Glu and GABA by removing the genomic region encoding the C-plug of GadC (a glutamate/GABA antiporter) to allow its transport path to remain open at a neutral pH, which improved the GABA productivity by 16.8% with 99.3 mol% conversion of 3 M L-Glu. Third, we enhanced the expression of soluble GadB by introducing the GroESL molecular chaperones, leading to 20.2% improvement in GABA productivity, with 307.40 g/L of GABA and a 61.48 g/L/h productivity obtained in one cycle. Finally, we inhibited the degradation of GABA by inactivation of gadA and gadB from the E. coli genome, which resulted in almost no GABA degradation after 40 h. After the cascade system modifications, the engineered recombinant E. coli strain achieved a 44.04 g/L/h productivity with a 99.6 mol% conversion of 3 M L-Glu in a 5-L bioreactor, about twofold increase in productivity compared to the starting strain. This increase represents the highest GABA productivity by whole-cell bioconversion using L-Glu as a substrate in one cycle observed

Association of plasma free amino acids with hyperuricemia in relation to diabetes mellitus, dyslipidemia, hypertension and metabolic syndrome

OpenAIRE

Mahbub, MH; Yamaguchi, Natsu; Takahashi, Hidekazu; Hase, Ryosuke; Ishimaru, Yasutaka; Sunagawa, Hiroshi; Amano, Hiroki; Kobayashi-Miura, Mikiko; Kanda, Hideyuki; Fujita, Yasuyuki; Yamamoto, Hiroshi; Yamamoto, Mai; Kikuchi, Shinya; Ikeda, Atsuko; Kageyama, Naoko

2017-01-01

Previous studies demonstrated independent contributions of plasma free amino acids (PFAAs) and high uric acid (UA) concentrations to increased risks of lifestyle-related diseases (LSRDs), but the important associations between these factors and LSRDs remain unknown. We quantified PFAAs and UA amongst Japanese subjects without LSRDs (no-LSRD, n = 2805), and with diabetes mellitus (DM, n = 415), dyslipidemia (n = 3207), hypertension (n = 2736) and metabolic syndrome (MetS, n = 717). The concent...

Emerging Role of D-Amino Acid Metabolism in the Innate Defense

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Jumpei Sasabe

2018-05-01

Full Text Available Mammalian innate and adaptive immune systems use the pattern recognition receptors, such as toll-like receptors, to detect conserved bacterial and viral components. Bacteria synthesize diverse D-amino acids while eukaryotes and archaea generally produce two D-amino acids, raising the possibility that many of bacterial D-amino acids are bacteria-specific metabolites. Although D-amino acids have not been identified to bind to any known pattern recognition receptors, D-amino acids are enantioselectively recognized by some other receptors and enzymes including a flavoenzyme D-amino acid oxidase (DAO in mammals. At host–microbe interfaces in the neutrophils and intestinal mucosa, DAO catalyzes oxidation of bacterial D-amino acids, such as D-alanine, and generates H2O2, which is linked to antimicrobial activity. Intestinal DAO also modifies the composition of microbiota through modulation of growth for some bacteria that are dependent on host nutrition. Furthermore, regulation and recognition of D-amino acids in mammals have additional meanings at various host–microbe interfaces; D-phenylalanine and D-tryptophan regulate chemotaxis of neutrophils through a G-coupled protein receptor, D-serine has a bacteriostatic role in the urinary tract, D-phenylalanine and D-leucine inhibit innate immunity through the sweet taste receptor in the upper airway, and D-tryptophan modulates immune tolerance in the lower airway. This mini-review highlights recent evidence supporting the hypothesis that D-amino acids are utilized as inter-kingdom communication at host–microbe interface to modulate bacterial colonization and host defense.

Amino acid metabolism in plant leaf, 1

International Nuclear Information System (INIS)

Ito, Osamu; Kumazawa, Kikuo

1977-01-01

14C-labelled sodium bicarbonate and 15N-labelled ammonium sulfate were simultaneously vacuum-infiltrated into detached sunflower leaves, and the incorporation of 14C and 15N into free amino acids was chased during 60-min period in the light and in the dark. In the light, the 14C specific activity of aspartic acid, alanine, serine and glycine rapidly increased for 5 min and thereafter decreased. On the other hand, that of glutamic acid continued to increase slowly during the entire 60-min period. In the dark, aspartic acid most actively incorporated 14C. The difference of changes in 14C specific activity between glutamic acid and other amino acids was also observed in the dark as in the light. These results suggest that the carbon skeleton of glutamic acid is synthesized from aspartic acid, alanine, serine and glycine. 15N content of glutamine was the highest of all amino acids investigated in the light, and it was followed by glutamic acid, alanine, aspartic acid, serine and glycine, in this order. In the dark, 15N content of glutamic acid fell remarkably and was lower than that of alanine up to 5 min. From these 15N tracer experiments, it is suggested that the incorporation of ammonium into glutamic acid is strictly dependent on light and that alanine incorporates ammonium by the direct animation besides the transamination from glutamic acid. (auth.)

Amino Acid Prodrugs: An Approach to Improve the Absorption of HIV-1 Protease Inhibitor, Lopinavir

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Mitesh Patel

2014-04-01

Full Text Available Poor systemic concentrations of lopinavir (LPV following oral administration occur due to high cellular efflux by P-glycoprotein (P-gp and multidrug resistance-associated proteins (MRPs and extensive metabolism by CYP3A4 enzymes. In this study, amino acid prodrugs of LPV were designed and investigated for their potential to circumvent efflux processes and first pass effects. Three amino acid prodrugs were synthesized by conjugating isoleucine, tryptophan and methionine to LPV. Prodrug formation was confirmed by the LCMS/MS and NMR technique. Interaction of LPV prodrugs with efflux proteins were carried out in P-gp (MDCK-MDR1 and MRP2 (MDCK-MRP2 transfected cells. Aqueous solubility studies demonstrated that prodrugs generate higher solubility relative to LPV. Prodrugs displayed higher stability under acidic conditions and degraded significantly with rise in pH. Uptake and transport data suggested that prodrugs carry significantly lower affinity towards P-gp and MRP2 relative to LPV. Moreover, prodrugs exhibited higher liver microsomal stability relative to LPV. Hence, amino acid prodrug modification might be a viable approach for enhancing LPV absorption across intestinal epithelial and brain endothelial cells which expresses high levels of P-gp and MRP2.

[The effects of a physical activity-behavior modification combined intervention(PABM-intervention) on metabolic risk factors in overweight and obese elementary school children].

Science.gov (United States)

Tak, Young-Ran; An, Ji-Yeon; Kim, Young-A; Woo, Hae-Young

2007-10-01

The purpose of this study was to identify the effects of a physical activity-behavior modification combined intervention(PABM-intervention) on metabolic risk factors in overweight and obese elementary school children. Thirty-two participants (BMI>or=85 percentile or relative obesity>or=10) were allocated to the PABM-intervention group and behavior modification only intervention group. The PABM-intervention was composed of exercise intervention consisting of 50 minutes of physical activity(Hip-hop dance & gym-based exercises) twice a week and the behavior modification intervention consisted of 50 minutes of instruction for modifying lifestyle habits(diet & exercise) once a week. Effectiveness of intervention was based on waist circumference, BP, HDL-cholesterol, TG, and fasting glucose before and after the intervention. The proportion of subjects with 1, 2, 3 or more metabolic risk factors were 28.1, 43.8, and 15.6%, respectively. After the 8-week intervention, waist circumference, systolic BP, diastolic BP, and HDL-cholesterol changed significantly(p<.01) in the PABM group. This provides evidence that a PABM-intervention is effective in changing metabolic risk factors such as waist circumference, systolic BP, diastolic BP, and HDL-cholesterol in overweight and obese elementary school children.

Determination of N metabolism parameters following 15N-amino acid infusion based on a mathematical model

International Nuclear Information System (INIS)

Pahle, T.; Koehler, R.; Souffrant, W.B.; Gebhardt, G.; Matkowitz, R.; Hartig, W.

1983-01-01

Two female pigs (25 kg live weight) received a continuous infusion of 15 N-glycine and 15 N-lysine solutions, resp., for 45 h and for further 72 h unlabelled amino acid solutions. The main protein and energy sources, however, were administered orally. The time course of the 15 N level and the differential urinary N excretion were determined from blood urea and urine. For the demonstration of synthesis and decay rates of the total body protein a mathematical model has been developed. The suitability of 15 N-lysine and 15 N-glycine for the determination of N metabolism parameters is discussed

Proteomic investigation of protein profile changes and amino acid residue-level modification in cooked lamb longissimus thoracis et lumborum: The effect of roasting.

Science.gov (United States)

Yu, Tzer-Yang; Morton, James D; Clerens, Stefan; Dyer, Jolon M

2016-09-01

Protein modifications of meat cooked by typical dry-heat methods (e.g., roasting) are currently not well understood. The present study utilised a shotgun proteomic approach to examine the molecular-level effect of roasting on thin lamb longissimus thoracis et lumborum patties, in terms of changes to both the protein profile and amino acid residue side-chain modifications. Cooking caused aggregation of actin, myosin heavy chains and sarcoplasmic proteins. Longer roasting time resulted in significantly reduced protein extractability as well as protein truncation involving particularly a number of myofibrillar and sarcoplasmic proteins, e.g., 6-phosphofructokinase, beta-enolase, l-lactate dehydrogenase A chain, alpha-actinin-3, actin and possibly myosin heavy chains. Modifications that have potential influence on nutritional properties, including carboxyethyllysine and a potentially glucose-derived N-terminal Amadori compound, were observed in actin and myoglobin after roasting. This study provided new insights into molecular changes resulting from the dry-heat treatment of meat, such as commonly used in food preparation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mixed matrix membranes for process intensification in electrodialysis of amino acids

NARCIS (Netherlands)

Kattan Readi, O.M.; Rolevink, Hendrikus H.M.; Nijmeijer, Dorothea C.

2014-01-01

BACKGROUND Amino acids are valuable intermediates in the biobased economy for the production of chemicals. Electro-membrane processes combined with enzymatic modification have been investigated as an alternative technology for the fractionation of a mixture of amino acids with almost identical

The metabolism of 14C labelled amino acid - A study from the radiological standpoint

International Nuclear Information System (INIS)

Jeanmaire, Lucien; Vernois, Yvette; Nazard, Raymonde.

1981-10-01

The metabolism of fifteen 14 C-labelled amino-acids has been studied in the rat during 680 days. The following results are presented and discussed: elimination by exhaled air, urine and feces; activity retention in 29 tissues or organs; cumulated activities from day 6 to 688. Elimination reached or exceeded 30% during the 48 first hours and then decreased. The retention in the whole body can be represented by three exponentials; one of them representing 3% of the activity would have a half-time of 1400 d. The cumulated activities in some tissues still increased significantly after 600 d. The respective doses in different tissues could vary of a factor 10; it was generally higher by a factor 5 than the doses obtained with glucose [fr

Studies with nitrogen-15-labelled amino acids for a quantitative description of nitrogen metabolism in man

International Nuclear Information System (INIS)

Hartig, W.; Faust, H.; Czarnetzki, H.D.; Winkler, E.; Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung)

1977-01-01

The utilization of glycine in healthy and stressed persons has been studied by continuous infusion or oral administration. The results of our studies show that (1) Breakdown of protein is increased in stress conditions; (2) Amino acids are also synthesized to protein in stress, the percentage of amino acids used for synthesis being smaller in stress conditions; (3) The urea synthesis during stress is increased and accelerated; (4) In the isotopic steady state 23% of the 15 N-glycine administered by infusion to healthy persons and 41% of the amount administered to patients after cholecystectomy is eliminated (urea 16%/26%; ammonia 4%/5%); using a single oral dose 24% is eliminated as total N after 24h (19% as 15 N-urea and 4% as 15 N-ammonia); (5) Depending on the method of gastric surgery the absorption and elimination rate of glycine-N varied; the more rapid intestinal absorption of glycine in comparison with healthy persons leads to a higher 15 N elimination via urine, and causes a disturbance of the nitrogen metabolism and nitrogen balance. (author)

More than just sugar: allocation of nectar amino acids and fatty acids in a Lepidopteran.

Science.gov (United States)

Levin, Eran; McCue, Marshall D; Davidowitz, Goggy

2017-02-08

The ability to allocate resources, even when limited, is essential for survival and fitness. We examine how nutrients that occur in minute amounts are allocated among reproductive, somatic, and metabolic demands. In addition to sugar, flower nectars contain two macronutrients-amino acids and fatty acids. We created artificial nectars spiked with 13 C-labelled amino acids and fatty acids and fed these to adult moths (Manduca sexta: Sphingidae) to understand how they allocate these nutrients among competing sinks (reproduction, somatic tissue, and metabolic fuel). We found that both essential and non-essential amino acids were allocated to eggs and flight muscles and were still detectable in early-instar larvae. Parental-derived essential amino acids were more conserved in the early-instars than non-essential amino acids. All amino acids were used as metabolic fuel, but the non-essential amino acids were oxidized at higher rates than essential amino acids. Surprisingly, the nectar fatty acids were not vertically transferred to offspring, but were readily used as a metabolic fuel by the moth, minimizing losses of endogenous nutrient stores. We conclude that the non-carbohydrate components of nectar may play important roles in both reproductive success and survival of these nectar-feeding animals. © 2017 The Author(s).

Uptake and conversion of D-amino acids in Arabidopsis thaliana.

Science.gov (United States)

Gördes, Dirk; Kolukisaoglu, Üner; Thurow, Kerstin

2011-02-01

The D-enantiomers of proteinogenic amino acids fulfill essential functions in bacteria, fungi and animals. Just in the plant kingdom, the metabolism and role of D-amino acids (D-AAs) still remains unclear, although plants have to cope with significant amounts of these compounds from microbial decay in the rhizosphere. To fill this gap of knowledge, we tested the inhibitory effects of D-AAs on plant growth and established a method to quantitate 16 out of 19 proteinogenic amino acids and their D-enantiomers in plant tissue extracts. Therefore, the amino acids in the extracts were derivatized with Marfey's reagent and separated by HPLC-MS. We used two ecotypes (Col-0 and C24) and a mutant (lht1) of the model plant Arabidopsis thaliana to determine the influence and fate of exogenously applied D-AAs. All of them were found in high concentrations in the plant extracts after application, even in lht1, which points to additional transporters facilitating the import of D-AAs. The addition of particular amino acids (D-Trp, D-Phe, D-Met and D-His) led to the accumulation of the corresponding L-amino acid. In almost all cases, the application of a D-AA resulted in the accumulation of D-Ala and D-Glu. The presented results indicate that soil borne D-AAs can actively be taken up and metabolized via central metabolic routes.

Modifications of Western-type diet regarding protein, fat and sucrose levels as modulators of steroid metabolism and activity in liver.

Science.gov (United States)

Krawczyńska, Agata; Herman, Andrzej P; Antushevich, Hanna; Bochenek, Joanna; Dziendzikowska, Katarzyna; Gajewska, Alina; Gromadzka-Ostrowska, Joanna

2017-01-01

The aim of the study was to evaluate whether the modification of the Western-type diet (high-fat, high-sucrose diet rich in saturated fatty acids) considering macronutrients content would influence hepatic metabolism and activity of steroids. For 3 weeks Wistar rat were fed the Western-type diet (21% fat, 35% sucrose, 19% protein, lard) and its modifications regarding dietary protein (10 and 19%), fat (5 and 21%) and sucrose (0 and 35%) levels. The steroid 5α-reductase type 1 (Srd5a1) and androgen receptor (Ar) gene expression as well as testosterone (T) conversion towards 5α-reduced derivatives in liver were positively correlated with body weight gain. The Western-type diets with decreased protein content regardless of the sucrose level exerted the most negative effect on the antioxidant system decreasing catalase (Cat), sodium dismutase (Sod1) and glutathione peroxidase (Gpx1) gene expression as well as Cat and Gpx activity and total antioxidant status, simultaneously intensifying lipid peroxidation. The impaired antioxidant system was accompanied by decreased level of hepatic T metabolism towards estrogens: 17β-estradiol (E2) and estriol, and increased estrogen receptor type 1 (Esr1) gene expression. Liver Esr1 mRNA level was differently correlated with T (positively) and E2 (negatively) plasma levels. Whereas the fat reduction in Western-type diet restored the plasma proportion between T and E2. In conclusion it could be stated that Western-type diet modification relating to protein, sucrose and fat content can influence hepatic steroid metabolism and activity; however the estrogens and androgens metabolism in liver would be connected with impairment of liver function or catabolic activity, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metabolic alterations, HFE gene mutations and atherogenic lipoprotein modifications in patients with primary iron overload.

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Meroño, Tomás; Brites, Fernando; Dauteuille, Carolane; Lhomme, Marie; Menafra, Martín; Arteaga, Alejandra; Castro, Marcelo; Saez, María Soledad; Ballerga, Esteban González; Sorroche, Patricia; Rey, Jorge; Lesnik, Philippe; Sordá, Juan Andrés; Chapman, M John; Kontush, Anatol; Daruich, Jorge

2015-05-01

Iron overload (IO) has been associated with glucose metabolism alterations and increased risk of cardiovascular disease (CVD). Primary IO is associated with mutations in the HFE gene. To which extent HFE gene mutations and metabolic alterations contribute to the presence of atherogenic lipoprotein modifications in primary IO remains undetermined. The present study aimed to assess small, dense low-density lipoprotein (LDL) levels, chemical composition of LDL and high-density lipoprotein (HDL) particles, and HDL functionality in IO patients. Eighteen male patients with primary IO and 16 sex- and age-matched controls were recruited. HFE mutations (C282Y, H63D and S65C), measures of insulin sensitivity and secretion (calculated from the oral glucose tolerance test), chemical composition and distribution profile of LDL and HDL subfractions (isolated by gradient density ultracentrifugation) and HDL functionality (as cholesterol efflux and antioxidative activity) were studied. IO patients compared with controls exhibited insulin resistance (HOMA-IR (homoeostasis model assessment-estimated insulin resistance): +93%, PHFE genotypes. C282Y homozygotes (n=7) presented a reduced β-cell function and insulin secretion compared with non-C282Y patients (n=11) (-58% and -73%, respectively, PHFE gene mutations are involved in the presence of atherogenic lipoprotein modifications in primary IO. To what extent such alterations could account for an increase in CVD risk remains to be determined.

Maternal Factors Are Associated with the Expression of Placental Genes Involved in Amino Acid Metabolism and Transport

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Day, Pricilla E.; Ntani, Georgia; Crozier, Sarah R.; Mahon, Pam A.; Inskip, Hazel M.; Cooper, Cyrus; Harvey, Nicholas C.; Godfrey, Keith M.; Hanson, Mark A.; Lewis, Rohan M.; Cleal, Jane K.

2015-01-01

Introduction Maternal environment and lifestyle factors may modify placental function to match the mother’s capacity to support the demands of fetal growth. Much remains to be understood about maternal influences on placental metabolic and amino acid transporter gene expression. We investigated the influences of maternal lifestyle and body composition (e.g. fat and muscle content) on a selection of metabolic and amino acid transporter genes and their associations with fetal growth. Methods RNA was extracted from 102 term Southampton Women’s Survey placental samples. Expression of nine metabolic, seven exchange, eight accumulative and three facilitated transporter genes was analyzed using quantitative real-time PCR. Results Increased placental LAT2 (p = 0.01), y + LAT2 (p = 0.03), aspartate aminotransferase 2 (p = 0.02) and decreased aspartate aminotransferase 1 (p = 0.04) mRNA expression associated with pre-pregnancy maternal smoking. Placental mRNA expression of TAT1 (p = 0.01), ASCT1 (p = 0.03), mitochondrial branched chain aminotransferase (p = 0.02) and glutamine synthetase (p = 0.05) was positively associated with maternal strenuous exercise. Increased glutamine synthetase mRNA expression (r = 0.20, p = 0.05) associated with higher maternal diet quality (prudent dietary pattern) pre-pregnancy. Lower LAT4 (r = -0.25, p = 0.05) and aspartate aminotransferase 2 mRNA expression (r = -0.28, p = 0.01) associated with higher early pregnancy diet quality. Lower placental ASCT1 mRNA expression associated with measures of increased maternal fat mass, including pre-pregnancy BMI (r = -0.26, p = 0.01). Lower placental mRNA expression of alanine aminotransferase 2 associated with greater neonatal adiposity, for example neonatal subscapular skinfold thickness (r = -0.33, p = 0.001). Conclusion A number of maternal influences have been linked with outcomes in childhood, independently of neonatal size; our finding of associations between placental expression of

Maternal Factors Are Associated with the Expression of Placental Genes Involved in Amino Acid Metabolism and Transport.

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Pricilla E Day

Full Text Available Maternal environment and lifestyle factors may modify placental function to match the mother's capacity to support the demands of fetal growth. Much remains to be understood about maternal influences on placental metabolic and amino acid transporter gene expression. We investigated the influences of maternal lifestyle and body composition (e.g. fat and muscle content on a selection of metabolic and amino acid transporter genes and their associations with fetal growth.RNA was extracted from 102 term Southampton Women's Survey placental samples. Expression of nine metabolic, seven exchange, eight accumulative and three facilitated transporter genes was analyzed using quantitative real-time PCR.Increased placental LAT2 (p = 0.01, y+LAT2 (p = 0.03, aspartate aminotransferase 2 (p = 0.02 and decreased aspartate aminotransferase 1 (p = 0.04 mRNA expression associated with pre-pregnancy maternal smoking. Placental mRNA expression of TAT1 (p = 0.01, ASCT1 (p = 0.03, mitochondrial branched chain aminotransferase (p = 0.02 and glutamine synthetase (p = 0.05 was positively associated with maternal strenuous exercise. Increased glutamine synthetase mRNA expression (r = 0.20, p = 0.05 associated with higher maternal diet quality (prudent dietary pattern pre-pregnancy. Lower LAT4 (r = -0.25, p = 0.05 and aspartate aminotransferase 2 mRNA expression (r = -0.28, p = 0.01 associated with higher early pregnancy diet quality. Lower placental ASCT1 mRNA expression associated with measures of increased maternal fat mass, including pre-pregnancy BMI (r = -0.26, p = 0.01. Lower placental mRNA expression of alanine aminotransferase 2 associated with greater neonatal adiposity, for example neonatal subscapular skinfold thickness (r = -0.33, p = 0.001.A number of maternal influences have been linked with outcomes in childhood, independently of neonatal size; our finding of associations between placental expression of transporter and metabolic genes and maternal smoking

Metabolomic Analyses of Leishmania Reveal Multiple Species Differences and Large Differences in Amino Acid Metabolism.

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Gareth D Westrop

Full Text Available Comparative genomic analyses of Leishmania species have revealed relatively minor heterogeneity amongst recognised housekeeping genes and yet the species cause distinct infections and pathogenesis in their mammalian hosts. To gain greater information on the biochemical variation between species, and insights into possible metabolic mechanisms underpinning visceral and cutaneous leishmaniasis, we have undertaken in this study a comparative analysis of the metabolomes of promastigotes of L. donovani, L. major and L. mexicana. The analysis revealed 64 metabolites with confirmed identity differing 3-fold or more between the cell extracts of species, with 161 putatively identified metabolites differing similarly. Analysis of the media from cultures revealed an at least 3-fold difference in use or excretion of 43 metabolites of confirmed identity and 87 putatively identified metabolites that differed to a similar extent. Strikingly large differences were detected in their extent of amino acid use and metabolism, especially for tryptophan, aspartate, arginine and proline. Major pathways of tryptophan and arginine catabolism were shown to be to indole-3-lactate and arginic acid, respectively, which were excreted. The data presented provide clear evidence on the value of global metabolomic analyses in detecting species-specific metabolic features, thus application of this technology should be a major contributor to gaining greater understanding of how pathogens are adapted to infecting their hosts.

Insight on the impacts of free amino acids and their metabolites on the immune system from a perspective of inborn errors of amino acid metabolism.

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Pakula, Malgorzata M; Maier, Thorsten J; Vorup-Jensen, Thomas

2017-06-01

Amino acids (AAs) support a broad range of functions in living organisms, including several that affect the immune system. The functions of the immune system are affected when free AAs are depleted or in excess because of external factors, such as starvation, or because of genetic factors, such as inborn errors of metabolism. Areas covered: In this review, we discuss the current insights into how free AAs affect immune responses. When possible, we make comparisons to known disease states resulting from inborn errors of metabolism, in which changed levels of AAs or AA metabolites provide insight into the impact of AAs on the human immune system in vivo. We also explore the literature describing how changes in AA levels might provide pharmaceutical targets for safe immunomodulatory treatment. Expert opinion: The impact of free AAs on the immune system is a neglected topic in most immunology textbooks. That neglect is undeserved, because free AAs have both direct and indirect effects on the immune system. Consistent choices of pre-clinical models and better strategies for creating formulations are required to gain clinical impact.

Function modification of SR-PSOX by point mutations of basic amino acids

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Chen Chunxia

2011-04-01

Full Text Available Abstract Background Atherosclerosis (AS is a common cardiovascular disease. Transformation of macrophages to form foam cells by internalizing modified low density-lipoprotein (LDL via scavenger receptor (SR is a key pathogenic process in the onset of AS. It has been demonstrated that SR-PSOX functions as either a scavenger receptor for uptake of atherogenic lipoproteins and bacteria or a membrane-anchored chemokine for adhesion of macrophages and T-cells to the endothelium. Therefore, SR-PSOX plays an important role in the development of AS. In this study the key basic amino acids in the chemokine domain of SR-PSOX have been identified for its functions. Results A cell model to study the functions of SR-PSOX was successfully established. Based on the cell model, a series of mutants of human SR-PSOX were constructed by replacing the single basic amino acid residue in the non-conservative region of the chemokine domain (arginine 62, arginine 78, histidine 80, arginine 82, histidine 85, lysine 105, lysine 119, histidine 123 with alanine (designated as R62A, R78A, H80A, R82A, H85A, K105A, K119A and H123A, respectively. Functional studies showed that the mutants with H80A, H85A, and K105A significantly increased the activities of oxLDL uptake and bacterial phagocytosis compared with the wild-type SR-PSOX. In addition, we have also found that mutagenesis of either of those amino acids strongly reduced the adhesive activity of SR-PSOX by using a highly non-overlapping set of basic amino acid residues. Conclusion Our study demonstrates that basic amino acid residues in the non-conservative region of the chemokine domain of SR-PSOX are critical for its functions. Mutation of H80, H85, and K105 is responsible for increasing SR-PSOX binding with oxLDL and bacteria. All the basic amino acids in this region are important in the cells adhesion via SR-PSOX. These findings suggest that mutagenesis of the basic amino acids in the chemokine domain of SR-PSOX may

Differential utilization of blood meal amino acids in mosquitoes

OpenAIRE

Miesfeld, Roger

2009-01-01

Guoli Zhou, Roger MiesfeldDepartment of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USAAbstract: Amino acids in the mosquito blood meal have two forms, protein-bound and plasma-free amino acids. To determine if the metabolic fate and flux of these two forms of blood meal amino acids are distinct, we fed mosquitoes eight [14C]-labeled amino acids, seven of which are essential for mosquitoes (leucine, valine, isoleucine, phenylalanine, lysine, arginine, histidine), and one th...

Transgenic manipulation of a single polyamine in poplar cells affects the accumulation of all amino acids

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Sridev Mohapatra; Rakesh Minocha; Stephanie Long; Subhash C. Minocha

2010-01-01

The polyamine metabolic pathway is intricately connected to metabolism of several amino acids. While ornithine and arginine are direct precursors of putrescine, they themselves are synthesized from glutamate in multiple steps involving several enzymes. Additionally, glutamate is an amino group donor for several other amino acids and acts as a substrate for biosynthesis...

Metabolism modifications and apoptosis induction after Cellfood™ administration to leukemia cell lines.

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Catalani, Simona; Carbonaro, Valentina; Palma, Francesco; Arshakyan, Marselina; Galati, Rossella; Nuvoli, Barbara; Battistelli, Serafina; Canestrari, Franco; Benedetti, Serena

2013-09-09

Cellfood™ (CF) is a nutritional supplement containing deuterium sulphate, minerals, amino acids, and enzymes, with well documented antioxidant properties. Its organic and inorganic components are extracted from the red algae Lithothamnion calcareum, whose mineral extract has shown growth-inhibitory effect both on in vitro and in vivo models. The purpose of this study was to evaluate the antiproliferative effects of CF on leukemic cells. In fact, according to its capacity to modulate O2 availability and to improve mitochondrial respiratory metabolism, we wondered if CF could affect cancer cell metabolism making cells susceptible to apoptosis. Three leukemic cell lines, Jurkat, U937, and K562, were treated with CF 5 μl/ml up to 72 hours. Cell viability, apoptosis (i.e. caspase-3 activity and DNA fragmentation), hypoxia inducible factor 1 alpha (HIF-1α) concentration, glucose transporter 1 (GLUT-1) expression, lactate dehydrogenase (LDH) activity and lactate release in the culture medium were detected and compared with untreated cells. CF significantly inhibited leukemic cell viability by promoting cell apoptosis, as revealed by caspase-3 activation and DNA laddering. In particular, CF treated cells showed lower HIF-1α levels and lower GLUT-1 expression as compared to untreated cells. At the same time, CF was able to reduce LDH activity and, consequently, the amount of lactate released in the extracellular environment. We supplied evidence for an antiproliferative effect of CF on leukemia cell lines by inducing cell death through an apoptotic mechanism and by altering cancer cell metabolism through HIF-1α and GLUT-1 regulation. Thanks to its antioxidative and proapoptotic properties, CF might be a good candidate for cancer prevention.

Topographical body fat distribution links to amino acid and lipid metabolism in healthy obese women [corrected].

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Francois-Pierre J Martin

Full Text Available Visceral adiposity is increasingly recognized as a key condition for the development of obesity related disorders, with the ratio between visceral adipose tissue (VAT and subcutaneous adipose tissue (SAT reported as the best correlate of cardiometabolic risk. In this study, using a cohort of 40 obese females (age: 25-45 y, BMI: 28-40 kg/m(2 under healthy clinical conditions and monitored over a 2 weeks period we examined the relationships between different body composition parameters, estimates of visceral adiposity and blood/urine metabolic profiles. Metabonomics and lipidomics analysis of blood plasma and urine were employed in combination with in vivo quantitation of body composition and abdominal fat distribution using iDXA and computerized tomography. Of the various visceral fat estimates, VAT/SAT and VAT/total abdominal fat ratios exhibited significant associations with regio-specific body lean and fat composition. The integration of these visceral fat estimates with metabolic profiles of blood and urine described a distinct amino acid, diacyl and ether phospholipid phenotype in women with higher visceral fat. Metabolites important in predicting visceral fat adiposity as assessed by Random forest analysis highlighted 7 most robust markers, including tyrosine, glutamine, PC-O 44∶6, PC-O 44∶4, PC-O 42∶4, PC-O 40∶4, and PC-O 40∶3 lipid species. Unexpectedly, the visceral fat associated inflammatory profiles were shown to be highly influenced by inter-days and between-subject variations. Nevertheless, the visceral fat associated amino acid and lipid signature is proposed to be further validated for future patient stratification and cardiometabolic health diagnostics.

Metabolic signatures of extreme longevity in northern Italian centenarians reveal a complex remodeling of lipids, amino acids, and gut microbiota metabolism.

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Sebastiano Collino

Full Text Available The aging phenotype in humans has been thoroughly studied but a detailed metabolic profiling capable of shading light on the underpinning biological processes of longevity is still missing. Here using a combined metabonomics approach compromising holistic (1H-NMR profiling and targeted MS approaches, we report for the first time the metabolic phenotype of longevity in a well characterized human aging cohort compromising mostly female centenarians, elderly, and young individuals. With increasing age, targeted MS profiling of blood serum displayed a marked decrease in tryptophan concentration, while an unique alteration of specific glycerophospholipids and sphingolipids are seen in the longevity phenotype. We hypothesized that the overall lipidome changes specific to longevity putatively reflect centenarians' unique capacity to adapt/respond to the accumulating oxidative and chronic inflammatory conditions characteristic of their extreme aging phenotype. Our data in centenarians support promotion of cellular detoxification mechanisms through specific modulation of the arachidonic acid metabolic cascade as we underpinned increased concentration of 8,9-EpETrE, suggesting enhanced cytochrome P450 (CYP enzyme activity. Such effective mechanism might result in the activation of an anti-oxidative response, as displayed by decreased circulating levels of 9-HODE and 9-oxoODE, markers of lipid peroxidation and oxidative products of linoleic acid. Lastly, we also revealed that the longevity process deeply affects the structure and composition of the human gut microbiota as shown by the increased extrection of phenylacetylglutamine (PAG and p-cresol sulfate (PCS in urine of centenarians. Together, our novel approach in this representative Italian longevity cohort support the hypothesis that a complex remodeling of lipid, amino acid metabolism, and of gut microbiota functionality are key regulatory processes marking exceptional longevity in humans.

Associations among circulating branched-chain amino acids and tyrosine with muscle volume and glucose metabolism in individuals without diabetes.

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Honda, Tatsuro; Kobayashi, Yoshinao; Togashi, Kenji; Hasegawa, Hiroshi; Iwasa, Motoh; Taguchi, Osamu; Takei, Yoshiyuki; Sumida, Yasuhiro

2016-05-01

Amino acid metabolites, including branched-chain amino acids (BCAA) and tyrosine (Tyr), affect glucose metabolism. The effects of BCAA on insulin resistance in patients with diabetes seem to conflict with mechanisms determined in animal models and cultured cells. The aim of this study was to clarify the controversy surrounding the effects of BCAA by investigating the physiological effects of BCAA and Tyr on glucose metabolism in healthy community dwellers. We investigated associations among BCAA and Tyr and metabolic parameters in 78 residents (median age, 52 y) of Mie, Japan, who did not have prediabetes, diabetes, or a body mass index >30 kg/m(2). Muscle volume, serum BCAA, and Tyr levels were higher in men than in women (n = 32 and 46, respectively; all P BCAA positively with muscle volume (regression coefficient/t/p/95% confidence interval, 281.8/3.7/0.0004/129.7-433.8), fasting blood glucose (FBG; 12699.4/3.22/0.0020/4830.9-20567.8), fasting immunoreactive insulin (IRI; 8505.1/2.75/0.0078/2322.5-14687.6), and homeostasis model assessment of β-cell function (HOMA-β; 893.6/2.58/0.0122/201.8-1585.5), and negatively with the HOMA-insulin resistance (HOMA-IR; -9294.1/-2.89/0.0052/-15711.0 to -2877.1). Tyr positively correlated with fasting IRI (26/2.77/0.0072/7.3-44.7). Insulin sensitivity and muscle volume are positively associated with BCAA in individuals without diabetes. In turn, BCAA correlate with increased FBG and fasting IRI levels. Tyr correlated with fasting IRI, but not with insulin sensitivity. Copyright © 2016 Elsevier Inc. All rights reserved.

Toward Sustainable Amino Acid Production.

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Usuda, Yoshihiro; Hara, Yoshihiko; Kojima, Hiroyuki

Because the global amino acid production industry has been growing steadily and is expected to grow even more in the future, efficient production by fermentation is of great importance from economic and sustainability viewpoints. Many systems biology technologies, such as genome breeding, omics analysis, metabolic flux analysis, and metabolic simulation, have been employed for the improvement of amino acid-producing strains of bacteria. Synthetic biological approaches have recently been applied to strain development. It is also important to use sustainable carbon sources, such as glycerol or pyrolytic sugars from cellulosic biomass, instead of conventional carbon sources, such as glucose or sucrose, which can be used as food. Furthermore, reduction of sub-raw substrates has been shown to lead to reduction of environmental burdens and cost. Recently, a new fermentation system for glutamate production under acidic pH was developed to decrease the amount of one sub-raw material, ammonium, for maintenance of culture pH. At the same time, the utilization of fermentation coproducts, such as cells, ammonium sulfate, and fermentation broth, is a useful approach to decrease waste. In this chapter, further perspectives for future amino acid fermentation from one-carbon compounds are described.

反刍动物瘤胃微生物限制性氨基酸代谢研究进展%Research Advances in Limiting Amino Acid Metabolism of Microorganisms in the Rumen

Institute of Scientific and Technical Information of China (English)

刘倩; 符潮; 周传社; 陈亮; 杨海

2017-01-01

随着反刍动物新蛋白质体系的提出,氨基酸营养研究随之进入崭新的局面.尤其是针对蛋白质、限制性氨基酸和肽的代谢,合理搭配日粮氨基酸,以及提高饲料蛋白质消化率和氮利用率成为反刍动物营养研究领域的新热点.本文综述了反刍动物瘤胃微生物在不同日粮条件下的氨基酸限制性顺序,限制性氨基酸的研究方法,理想的氨基酸模式,蛋氨酸与赖氨酸的代谢机理,以及限制性氨基酸代谢的影响因素,旨在为揭示反刍家畜瘤胃微生物限制性氨基酸代谢机理,建立调控反刍家畜氨基酸高效利用的营养技术方案提供理论依据和技术支持.%With a proposed new ruminant protein system,the study on amino acid nutrition entered into a new phase.The metabolism of proteins,limiting amino acids and peptides,amino acids with a reasonable diet,the improvement of feed protein digestibility and nitrogen utilization have become new hot topics in the field of ruminant nutrition.This paper reviewed the amino acid restrictive sequence,study methods of limiting amino acids,ideal amino acid research pattern,metabolic mechanism of methionine and lysine,and the influence factors of limiting amino acid metabolism of rumen microorganisms in different dietary conditions.It aims to provide a theoretical basis and technical support in revealing the rumen microbial metabolism mechanisms and establishing technical solutions of the efficient use of limiting amino acid in ruminant nutrition.

Effects of amino acid supplementations on metabolic and physiological parameters in Atlantic cod (Gadus morhua) under stress.

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Herrera, Marcelino; Herves, María Antonia; Giráldez, Inmaculada; Skar, Kristin; Mogren, Hanne; Mortensen, Atle; Puvanendran, Velmurugu

2017-04-01

The effects of tryptophan (Trp) and phenylalanine (Phe) diet supplementation on the stress and metabolism of the Atlantic cod have been studied. Fish were fed diet supplemented with Trp or Phe or control diet for 1 week. At the end of the feeding trial, fish were subjected to air exposure or heat shock. Following samples of blood, liver and muscle were taken from the fish and were analyzed for stress and metabolic indicators. After an air exposure, plasma cortisol levels in fish fed with Trp and Phe diets were lower compared to the fish fed the control diet. Diets containing both amino acids increased significantly the liver transaminase activities in juvenile cod. During thermal stress, high Trp contents had significant effects on fructose biphosphatase activity though Phe did not. Overall, activities of glucose 6-phosphate dehydrogenase, pyruvate kinase, and phosphofructokinase increased significantly for both amino acid diets. For the thermal stress, fish had the highest values of those activities for the 3Trp diet. Trp content in the diet had significant effects on the transaminase activity in muscle during air stress compared to fish fed control and Phe diets. Muscle alanine transaminase activity for thermal stress in fish fed any diet was not significantly different from the control. Both Trp and Phe supplementations reduced the stress markers in the cod; hence, they could be used as additives for the stress attenuation. However, they also raised the activity of key enzymes in glycolysis and gluconeogenesis, mainly the Trp diets.

Growth and clinical variables in nitrogen-restricted piglets fed an adjusted essential amino acid mix: Effects using free amino acid-based diets

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Excess protein intake in early life has been linked to obesity and metabolic syndrome in later life. Yet, protein, and in particular the essential amino acids (EAA), need to be present in adequate quantity to support growth. Using a piglet model restricted in dietary amino acids (AA), our objective...

Quantitation of some amino-terminal residues in proteins using 3H-labelled dansyl chloride and 14C labelled amino acids

International Nuclear Information System (INIS)

Flengsrud, R.

1979-01-01

A method for quantitation of amino-terminal residues in proteins is presented. The method is a modification of a double isotope-labelling technique, using 3 H-labelled dansyl chloride and 14 C-labelled amino acids as internal standards. The method is demonstrated on human fibrinogen, horse myoglobin and on mouse myoloma IgA. A linear relationship between the ratio 3 H/ 14 C in the separated amino-terminal amino acid of the protein and the amount of protein added in the labelling mixture was obtained with standard deviations of +- 7.4%, +-3.4% and +-10.3%, respectively. An application of the method is demonstrated by measuring the increase in amino-terminal glycine in fibrinogen following the proteolytic action of thrombin. The method seems to be useful when 0.1 nmol or more of protein is used. (author)

Amino acid analysis in biological fluids by GC-MS

OpenAIRE

Kaspar, Hannelore

2009-01-01

Amino acids are intermediates in cellular metabolism and their quantitative analysis plays an important role in disease diagnostics. A gas chromatography-mass spectrometry (GC-MS) based method was developed for the quantitative analysis of free amino acids as their propyl chloroformate derivatives in biological fluids. Derivatization with propyl chloroformate could be carried out directly in the biological samples without prior protein precipitation or solid-phase extraction of the amino acid...

Probiotic modulation of symbiotic gut microbial–host metabolic interactions in a humanized microbiome mouse model

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Martin, Francois-Pierre J; Wang, Yulan; Sprenger, Norbert; Yap, Ivan K S; Lundstedt, Torbjörn; Lek, Per; Rezzi, Serge; Ramadan, Ziad; van Bladeren, Peter; Fay, Laurent B; Kochhar, Sunil; Lindon, John C; Holmes, Elaine; Nicholson, Jeremy K

2008-01-01

The transgenomic metabolic effects of exposure to either Lactobacillus paracasei or Lactobacillus rhamnosus probiotics have been measured and mapped in humanized extended genome mice (germ-free mice colonized with human baby flora). Statistical analysis of the compartmental fluctuations in diverse metabolic compartments, including biofluids, tissue and cecal short-chain fatty acids (SCFAs) in relation to microbial population modulation generated a novel top-down systems biology view of the host response to probiotic intervention. Probiotic exposure exerted microbiome modification and resulted in altered hepatic lipid metabolism coupled with lowered plasma lipoprotein levels and apparent stimulated glycolysis. Probiotic treatments also altered a diverse range of pathways outcomes, including amino-acid metabolism, methylamines and SCFAs. The novel application of hierarchical-principal component analysis allowed visualization of multicompartmental transgenomic metabolic interactions that could also be resolved at the compartment and pathway level. These integrated system investigations demonstrate the potential of metabolic profiling as a top-down systems biology driver for investigating the mechanistic basis of probiotic action and the therapeutic surveillance of the gut microbial activity related to dietary supplementation of probiotics. PMID:18197175

Amino acid fermentation at the origin of the genetic code.

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de Vladar, Harold P

2012-02-10

There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP) yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can act and refine the assignments

Mycobacterium Lysine ε-aminotransferase is a novel alarmone metabolism related persister gene via dysregulating the intracellular amino acid level.

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Duan, Xiangke; Li, Yunsong; Du, Qinglin; Huang, Qinqin; Guo, Siyao; Xu, Mengmeng; Lin, Yanping; Liu, Zhidong; Xie, Jianping

2016-01-25

Bacterial persisters, usually slow-growing, non-replicating cells highly tolerant to antibiotics, play a crucial role contributing to the recalcitrance of chronic infections and treatment failure. Understanding the molecular mechanism of persister cells formation and maintenance would obviously inspire the discovery of new antibiotics. The significant upregulation of Mycobacterium tuberculosis Rv3290c, a highly conserved mycobacterial lysine ε-aminotransferase (LAT) during hypoxia persistent model, suggested a role of LAT in persistence. To test this, a lat deleted Mycobacterium smegmatis was constructed. The expression of transcriptional regulator leucine-responsive regulatory protein (LrpA) and the amino acids abundance in M. smegmatis lat deletion mutants were lowered. Thus, the persistence capacity of the deletion mutant was impaired upon norfloxacin exposure under nutrient starvation. In summary, our study firstly reported the involvement of mycobacterium LAT in persister formation, and possibly through altering the intracellular amino acid metabolism balance.

Effects of water turbulence on variations in cell ultrastructure and metabolism of amino acids in the submersed macrophyte, Elodea nuttallii (Planch.) H. St. John.

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Atapaththu, K S S; Miyagi, A; Atsuzawa, K; Kaneko, Y; Kawai-Yamada, M; Asaeda, T

2015-09-01

The interactions between macrophytes and water movement are not yet fully understood, and the causes responsible for the metabolic and ultrastructural variations in plant cells as a consequence of turbulence are largely unknown. In the present study, growth, metabolism and ultrastructural changes were evaluated in the aquatic macrophyte Elodea nuttallii, after exposure to turbulence for 30 days. The turbulence was generated with a vertically oscillating horizontal grid. The turbulence reduced plant growth, plasmolysed leaf cells and strengthened cell walls, and plants exposed to turbulence accumulated starch granules in stem chloroplasts. The size of the starch granules increased with the magnitude of the turbulence. Using capillary electrophoresis-mass spectrometry (CE-MS), analysis of the metabolome found metabolite accumulation in response to the turbulence. Asparagine was the dominant amino acid that was concentrated in stressed plants, and organic acids such as citrate, ascorbate, oxalate and γ-amino butyric acid (GABA) also accumulated in response to turbulence. These results indicate that turbulence caused severe stress that affected plant growth, cell ultrastructure and some metabolic functions of E. nuttallii. Our findings offer insights to explain the effects of water movement on the functions of aquatic plants. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

The Molecular and Cellular Effect of Homocysteine Metabolism Imbalance on Human Health

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Henrieta Škovierová

2016-10-01

Full Text Available Homocysteine (Hcy is a sulfur-containing non-proteinogenic amino acid derived in methionine metabolism. The increased level of Hcy in plasma, hyperhomocysteinemia, is considered to be an independent risk factor for cardio and cerebrovascular diseases. However, it is still not clear if Hcy is a marker or a causative agent of diseases. More and more research data suggest that Hcy is an important indicator for overall health status. This review represents the current understanding of molecular mechanism of Hcy metabolism and its link to hyperhomocysteinemia-related pathologies in humans. The aberrant Hcy metabolism could lead to the redox imbalance and oxidative stress resulting in elevated protein, nucleic acid and carbohydrate oxidation and lipoperoxidation, products known to be involved in cytotoxicity. Additionally, we examine the role of Hcy in thiolation of proteins, which results in their molecular and functional modifications. We also highlight the relationship between the imbalance in Hcy metabolism and pathogenesis of diseases, such as cardiovascular diseases, neurological and psychiatric disorders, chronic kidney disease, bone tissue damages, gastrointestinal disorders, cancer, and congenital defects.

The Janus Face of PAMAM Dendrimers Used to Potentially Cure Nonenzymatic Modifications of Biomacromolecules in Metabolic Disorders—A Critical Review of the Pros and Cons

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Cezary Watala

2013-11-01

Full Text Available Diabetes mellitus, which is characterised by high blood glucose levels and the burden of various macrovascular and microvascular complications, is a cause of much human suffering across the globe. While the use of exogenous insulin and other medications can control and sometimes prevent various diabetes-associated sequelae, numerous diabetic complications are still commonly encountered in diabetic patients. Therefore, there is a strong need for safe and effective antihyperglycaemic agents that provide an alternative or compounding option for the treatment of diabetes. In recent years, amino-terminated poly(amidoamine (PAMAM dendrimers (G2, G3 and G4 have attracted attention due to their protective value as anti-glycation and anti-carbonylation agents that can be used to limit the nonenzymatic modifications of biomacromolecules. The focus of this review is to present a detailed survey of our own data, as well as of the available literature regarding the toxicity, pharmacological properties and overall usefulness of PAMAM dendrimers. This presentation pays particular and primary attention to their therapeutic use in poorly controlled diabetes and its complications, but also in other conditions, such as Alzheimer’s disease, in which such nonenzymatic modifications may underlie the pathophysiological mechanisms. The impact of dendrimer administration on the overall survival of diabetic animals and on glycosylation, glycoxidation, the brain-blood barrier and cellular bioenergetics are demonstrated. Finally, we critically discuss the potential advantages and disadvantages accompanying the use of PAMAM dendrimers in the treatment of metabolic impairments that occur under conditions of chronic hyperglycaemia.

Programming Post-Translational Control over the Metabolic Labeling of Cellular Proteins with a Noncanonical Amino Acid.

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Thomas, Emily E; Pandey, Naresh; Knudsen, Sarah; Ball, Zachary T; Silberg, Jonathan J

2017-08-18

Transcriptional control can be used to program cells to label proteins with noncanonical amino acids by regulating the expression of orthogonal aminoacyl tRNA synthetases (aaRSs). However, we cannot yet program cells to control labeling in response to aaRS and ligand binding. To identify aaRSs whose activities can be regulated by interactions with ligands, we used a combinatorial approach to discover fragmented variants of Escherichia coli methionyl tRNA synthetase (MetRS) that require fusion to associating proteins for maximal activity. We found that these split proteins could be leveraged to create ligand-dependent MetRS using two approaches. When a pair of MetRS fragments was fused to FKBP12 and the FKBP-rapamycin binding domain (FRB) of mTOR and mutations were introduced that direct substrate specificity toward azidonorleucine (Anl), Anl metabolic labeling was significantly enhanced in growth medium containing rapamycin, which stabilizes the FKBP12-FRB complex. In addition, fusion of MetRS fragments to the termini of the ligand-binding domain of the estrogen receptor yielded proteins whose Anl metabolic labeling was significantly enhanced when 4-hydroxytamoxifen (4-HT) was added to the growth medium. These findings suggest that split MetRS can be fused to a range of ligand-binding proteins to create aaRSs whose metabolic labeling activities depend upon post-translational interactions with ligands.

Nature and Nurture: What Determines Tumor Metabolic Phenotypes?

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Mayers, Jared R; Vander Heiden, Matthew G

2017-06-15

Understanding the genetic basis of cancer has led to therapies that target driver mutations and has helped match patients with more personalized drugs. Oncogenic mutations influence tumor metabolism, but other tumor characteristics can also contribute to their metabolic phenotypes. Comparison of isogenic lung and pancreas tumor models suggests that use of some metabolic pathways is defined by lineage rather than by driver mutation. Lung tumors catabolize circulating branched chain amino acids (BCAA) to extract nitrogen for nonessential amino acid and nucleotide synthesis, whereas pancreatic cancer obtains amino acids from catabolism of extracellular protein. These differences in amino acid metabolism translate into distinct pathway dependencies, as genetic disruption of the enzymes responsible for utilization of BCAA nitrogen limits the growth of lung tumors, but not pancreatic tumors. These data argue that some cancer metabolic phenotypes are defined by cancer tissue-of-origin and environment and that these features constrain the influence of genetic mutations on metabolism. A better understanding of the factors defining tumor nutrient utilization could be exploited to help improve cancer therapy. Cancer Res; 77(12); 3131-4. ©2017 AACR . ©2017 American Association for Cancer Research.

Low Mass MS/MS Fragments of Protonated Amino Acids Used for Distinction of Their 13C- Isotopomers in Metabolic Studies

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Ma, Xin; Dagan, Shai; Somogyi, Árpád; Wysocki, Vicki H.; Scaraffia, Patricia Y.

2013-04-01

Glu, Gln, Pro, and Ala are the main amino acids involved in ammonia detoxification in mosquitoes. In order to develop a tandem mass spectrometry method (MS2) to monitor each carbon of the above isotopically-labeled 13C-amino acids for metabolic studies, the compositions and origins of atoms in fragments of the protonated amino acid should be first elucidated. Thus, various electrospray (ESI)-based MS2 tools were employed to study the fragmentation of these unlabeled and isotopically-labeled amino acids and better understand their dissociation pathways. A broad range of fragments, including previously-undescribed low m/z fragments was revealed. The formulae of the fragments (from m/z 130 down to m/z 27) were confirmed by their accurate masses. The structures and conformations of the larger fragments of Glu were also explored by ion mobility mass spectrometry (IM-MS) and gas-phase hydrogen/deuterium exchange (HDX) experiments. It was found that some low m/z fragments ( m/z 27-30) are common to Glu, Gln, Pro, and Ala. The origins of carbons in these small fragments are discussed and additional collision induced dissociation (CID) MS2 fragmentation pathways are proposed for them. It was also found that small fragments (≤ m/z 84) of protonated, methylated Glu, and methylated Gln are the same as those of the underivatized Glu and Gln. Taken together, the new approach of utilizing low m/z fragments can be applied to distinguish, identify, and quantify 13C-amino acids labeled at various positions, either in the backbone or side chain.

Amino acid starvation has opposite effects on mitochondrial and cytosolic protein synthesis.

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Mark A Johnson

Full Text Available Amino acids are essential for cell growth and proliferation for they can serve as precursors of protein synthesis, be remodelled for nucleotide and fat biosynthesis, or be burnt as fuel. Mitochondria are energy producing organelles that additionally play a central role in amino acid homeostasis. One might expect mitochondrial metabolism to be geared towards the production and preservation of amino acids when cells are deprived of an exogenous supply. On the contrary, we find that human cells respond to amino acid starvation by upregulating the amino acid-consuming processes of respiration, protein synthesis, and amino acid catabolism in the mitochondria. The increased utilization of these nutrients in the organelle is not driven primarily by energy demand, as it occurs when glucose is plentiful. Instead it is proposed that the changes in the mitochondrial metabolism complement the repression of cytosolic protein synthesis to restrict cell growth and proliferation when amino acids are limiting. Therefore, stimulating mitochondrial function might offer a means of inhibiting nutrient-demanding anabolism that drives cellular proliferation.

Amino acid and glucose metabolism in fed-batch CHO cell culture affects antibody production and glycosylation

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Fan, Yuzhou; Jimenez Del Val, Ioscani; Müller, Christian

2015-01-01

optimization, especially media optimization. Gaining knowledge on their interrelations could provide insight for obtaining higher immunoglobulin G (IgG) titer and better controlling glycosylationrelated product quality. In this work, different fed-batch processes with two chemically defined proprietary media......Fed-batch Chinese hamster ovary (CHO) cell culture is the most commonly used process for IgG production in the biopharmaceutical industry. Amino acid and glucose consumption, cell growth, metabolism, antibody titer, and N-glycosylation patterns are always the major concerns during upstream process...... and glutamine concentrations and uptake rates were positively correlated with intracellular UDP-Gal availability. All these findings are important for optimization of fed-batch culture for improving IgG production and directing glycosylation quality....

Supplementation of branched-chain amino acids in protein-restricted diets modulates the expression levels of amino acid transporters and energy metabolism associated regulators in the adipose tissue of growing pigs

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Yinghui Li

2016-03-01

Full Text Available This experiment was conducted to investigate the effects of branched-chain amino acids (BCAA supplemented in protein-restricted diets on the growth performance and the expression profile of amino acid transporters and energy metabolism related regulators in the white adipose tissue (WAT of different regional depots including dorsal subcutaneous adipose (DSA and abdominal subcutaneous adipose (ASA. A total of 24 crossbred barrows (7.40 ± 0.70 kg were randomly divided into 4 groups and were fed the following isocaloric diets for 33 days: 1 a recommended adequate protein diet (AP, 20% CP, as a positive control; 2 a low protein diet (LP, 17% CP; 3 the LP diet supplemented with BCAA (LP + B, 17% CP to reach the same level of the AP diet group; 4 the LP diet supplemented with 2 times the amount of BCAA (LP + 2B, 17% CP. The daily gain and daily feed intake of the LP diet group were the lowest among all the treatments (P  0.05. Moreover, BCAA supplementation down-regulated the expression levels of amino acid transporters including L-type amino acid transporter 1 and sodium-coupled neutral amino acid transporter 2 in DSA, but up-regulated the expression level of L-type amino acid transporter 4 in ASA (P < 0.05. Meanwhile, the energy sensor AMP-activated protein kinase α was activated in the DSA of pigs fed LP diet and in the ASA of the pigs fed AP or LP + 2B diets (P < 0.05. The mRNA expression profile of the selected mitochondrial component and mitochondrial biogenesis associated regulators in DSA and ASA also responded differently to dietary BCAA supplementation. These results suggested that the growth performance of growing pigs fed protein restricted diets supplemented with BCAA could catch up to that of the pigs fed AP diets. The results also partly demonstrated that the regulation mechanisms of BCAA are different in the adipose tissues of different depots.

Quantitative amino acid profiling and stable isotopically labeled amino acid tracer enrichment used for in vivo human systemic and tissue kinetics measurements

DEFF Research Database (Denmark)

Bornø, Andreas; van Hall, Gerrit

2014-01-01

An important area within clinical functional metabolomics is in vivo amino acid metabolism and protein turnover measurements for which accurate amino acid concentrations and stable isotopically labeled amino acid enrichments are mandatory not the least when tissue metabolomics is determined....... The present study describes a new sensitive liquid chromatography tandem mass-spectrometry method quantifying 20 amino acids and their tracer(s) ([ring-(13)C6]/D5Phenylalanine) in human plasma and skeletal muscle specimens. Before analysis amino acids were extracted and purified via deprotonization....../ion exchange, derivatized using a phenylisothiocyanate reagent and each amino acid was quantitated with its own stable isotopically labeled internal standard (uniformly labeled-(13)C/(15)N). The method was validated according to general recommendations for chromatographic analytical methods. The calibration...

Induction of resistance to gray mold with benzothiadiazole modifies amino acid profile and increases proanthocyanidins in grape: primary versus secondary metabolism.

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Iriti, Marcello; Rossoni, Mara; Borgo, Michele; Ferrara, Luigia; Faoro, Franco

2005-11-16

Field treatments of grapevine (cv. Merlot) with the plant activator benzothiadiazole (BTH, 0.3 mM) induced resistance against gray mold caused by Botrytis cinerea. Both incidence and severity of the disease were reduced. The resistance was associated with an increase of total polyphenols in berry skins, in particular, the proanthocyanidin fraction, that increased up to 36%. The amino acid profile of leaves was also modified by treatments, particularly lysine, that augmented 4-fold. Other amino acids involved in resistance mechanisms to either biotic or abiotic stress increased as well. These results indicate that BTH treatments can be used to control gray mold, thereby limiting an excessive use of fungicides, and could be exploited to increase the content of micronutrients of high nutritional value, arising from both primary and secondary metabolisms.

Deuterium oxide as a tool for the study of amino acid metabolism

International Nuclear Information System (INIS)

Mitra, R.; Burton, J.; Varner, J.E.

1976-01-01

We have used deuterium oxide in nontoxic concentrations to study, in intact seedlings, the biosynthesis of amino acids. The extent and pattern of deuteration, as determined by a gas--liquid chromatograph--mass spectrometer system, permits conclusions about the biosynthesis of individual amino acids and also about their exposure to transaminases and other enzymes that might introduce deuterium into specific positions of the amino acid by exchange. This method could be used to study amino acid biogenesis in any organism that can tolerate 20 to 40 percent deuterium oxide for a period of a few hours to a few days

Determination of N metabolism parameters following /sup 15/N-amino acid infusion based on a mathematical model

Energy Technology Data Exchange (ETDEWEB)

Pahle, T; Koehler, R; Souffrant, W B; Gebhardt, G [Karl-Marx-Universitaet, Leipzig (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin; Matkowitz, R; Hartig, W [Bezirkskrankenhaus Leipzig (German Democratic Republic). Chirurgische Klinik

1983-01-01

Two female pigs (25 kg live weight) received a continuous infusion of /sup 15/N-glycine and /sup 15/N-lysine solutions, resp., for 45 h and for further 72 h unlabelled amino acid solutions. The main protein and energy sources, however, were administered orally. The time course of the /sup 15/N level and the differential urinary N excretion were determined from blood urea and urine. For the demonstration of synthesis and decay rates of the total body protein a mathematical model has been developed. The suitability of /sup 15/N-lysine and /sup 15/N-glycine for the determination of N metabolism parameters is discussed.

Trend analysis of the correlation of amino acid plasma profile with glycemic status in Saudi diabetic patients

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Fahad A. Al-Abbasi

2012-10-01

Full Text Available The role of amino acids in diabetes mellitus and its metabolic traits have been suggested previously; however, studied to a very limited scale in the Saudi patient population. Patients diagnosed with diabetes mellitus were included in the current clinical study. Sample was representative and in accordance with the national population distribution. Blood samples were drawn and assayed for glucose, total cholesterol, triglyceride, high density lipoprotein and low density lipoprotein. General biochemical markers, such as alkaline phosphatase (ALP, creatinine kinase (CK, aspartate transaminase (AST, alanine transaminase (ALT and blood urea nitrogen (BUN were assessed. Serum amino acids of different categories (essential, semi-essential and metabolic indicator amino acids were assessed. Correlation co-efficient between each amino acid and serum glucose level was calculated. The current study showed positive correlation between amino acid level and glucose serum concentration in male while it showed negative correlation in female Saudi diabetic patients. Male patients had significantly higher methionine concentration parallel to their glycemic status. Metabolic indicator amino acids significantly changed in concordance with the glycemic status of female patients more than in male patients. In conclusion, serum amino acid is positively correlated with glycemic status in Saudi male diabetic patients while negatively correlated in female patients. Yet, further study would be recommended to utilize serum amino acid profile as surrogate parameter for the metabolic complications of diabetes mellitus.

Uptake of Amino Acids and Their Metabolic Conversion into the Compatible Solute Proline Confers Osmoprotection to Bacillus subtilis

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Zaprasis, Adrienne; Bleisteiner, Monika; Kerres, Anne; Hoffmann, Tamara

2014-01-01

The data presented here reveal a new facet of the physiological adjustment processes through which Bacillus subtilis can derive osmostress protection. We found that the import of proteogenic (Glu, Gln, Asp, Asn, and Arg) and of nonproteogenic (Orn and Cit) amino acids and their metabolic conversion into proline enhances growth under otherwise osmotically unfavorable conditions. Osmoprotection by amino acids depends on the functioning of the ProJ-ProA-ProH enzymes, but different entry points into this biosynthetic route are used by different amino acids to finally yield the compatible solute proline. Glu, Gln, Asp, and Asn are used to replenish the cellular pool of glutamate, the precursor for proline production, whereas Arg, Orn, and Cit are converted into γ-glutamic semialdehyde/Δ1-pyrroline-5-carboxylate, an intermediate in proline biosynthesis. The import of Glu, Gln, Asp, Asn, Arg, Orn, and Cit did not lead to a further increase in the size of the proline pool that is already present in osmotically stressed cells. Hence, our data suggest that osmoprotection of B. subtilis by this group of amino acids rests on the savings in biosynthetic building blocks and energy that would otherwise have to be devoted either to the synthesis of the proline precursor glutamate or of proline itself. Since glutamate is the direct biosynthetic precursor for proline, we studied its uptake and found that GltT, an Na+-coupled symporter, is the main uptake system for both glutamate and aspartate in B. subtilis. Collectively, our data show how effectively B. subtilis can exploit environmental resources to derive osmotic-stress protection through physiological means. PMID:25344233

Effects of an eight-week supervised, structured lifestyle modification programme on anthropometric, metabolic and cardiovascular risk factors in severely obese adults.

LENUS (Irish Health Repository)

Crowe, Catherine

2015-08-01

Lifestyle modification is fundamental to obesity treatment, but few studies have described the effects of structured lifestyle programmes specifically in bariatric patients. We sought to describe changes in anthropometric and metabolic characteristics in a cohort of bariatric patients after participation in a nurse-led, structured lifestyle programme.

The Role of Circulating Amino Acids in the Hypothalamic Regulation of Liver Glucose Metabolism.

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Arrieta-Cruz, Isabel; Gutiérrez-Juárez, Roger

2016-07-01

A pandemic of diabetes and obesity has been developing worldwide in close association with excessive nutrient intake and a sedentary lifestyle. Variations in the protein content of the diet have a direct impact on glucose homeostasis because amino acids (AAs) are powerful modulators of insulin action. In this work we review our recent findings on how elevations in the concentration of the circulating AAs leucine and proline activate a metabolic mechanism located in the mediobasal hypothalamus of the brain that sends a signal to the liver via the vagus nerve, which curtails glucose output. This neurogenic signal is strictly dependent on the metabolism of leucine and proline to acetyl-coenzyme A (CoA) and the subsequent production of malonyl-CoA; the signal also requires functional neuronal ATP-sensitive potassium channels. The liver then responds by lowering the rate of gluconeogenesis and glycogenolysis, ultimately leading to a net decrease in glucose production and in concentrations of circulating glucose. Furthermore, we review here how our work with proline suggests a new role of astrocytes in the central regulation of glycemia. Last, we outline how factors such as the consumption of fat-rich diets can interfere with glucoregulatory mechanisms and, in the long term, may contribute to the development of hyperglycemia, a hallmark of type 2 diabetes. © 2016 American Society for Nutrition.

Discovery and History of Amino Acid Fermentation.

Science.gov (United States)

Hashimoto, Shin-Ichi

There has been a strong demand in Japan and East Asia for L-glutamic acid as a seasoning since monosodium glutamate was found to present umami taste in 1907. The discovery of glutamate fermentation by Corynebacterium glutamicum in 1956 enabled abundant and low-cost production of the amino acid, creating a large market. The discovery also prompted researchers to develop fermentative production processes for other L-amino acids, such as lysine. Currently, the amino acid fermentation industry is so huge that more than 5 million metric tons of amino acids are manufactured annually all over the world, and this number continues to grow. Research on amino acid fermentation fostered the notion and skills of metabolic engineering which has been applied for the production of other compounds from renewable resources. The discovery of glutamate fermentation has had revolutionary impacts on both the industry and science. In this chapter, the history and development of glutamate fermentation, including the very early stage of fermentation of other amino acids, are reviewed.

Radiation-induced increase in the release of amino acids by isolated, perfused skeletal muscle

International Nuclear Information System (INIS)

Schwenen, M.

1989-01-01

Local exposure of the hindquarter of the rat to 15Gy of gamma-radiation resulted, 4-6h after irradiation, in increased release of amino acids by the isolated, perfused hindquarter preparation, 70% of which is skeletal muscle. This increase in release involves not only alanine and glutamine, but also those amino acids not metabolized by muscle and, therefore, released in proportion to their occurrence in muscle proteins. Because metabolic parameters and content of energy-rich phosphate compounds in muscle remain unchanged, it is unlikely that general cellular damage is the underlying cause of the radiation-induced increase in amino acid release. The findings strongly favour the hypothesis that increased availability of amino acids results from enhanced protein break-down in skeletal muscle which has its onset shortly after irradiation. This radiation-induced disturbance in protein metabolism might be one of the pathogenetic factors in the aetiology of radiation myopathy. (author)

Side Chain Cyclized Aromatic Amino Acids

DEFF Research Database (Denmark)

Van der Poorten, Olivier; Knuhtsen, Astrid; Sejer Pedersen, Daniel

2016-01-01

Constraining the conformation of flexible peptides is a proven strategy to increase potency, selectivity, and metabolic stability. The focus has mostly been on constraining the backbone dihedral angles; however, the correct orientation of the amino acid side chains (χ-space) that constitute...... the peptide pharmacophore is equally important. Control of χ-space utilizes conformationally constrained amino acids that favor, disfavor, or exclude the gauche (-), the gauche (+), or the trans conformation. In this review we focus on cyclic aromatic amino acids in which the side chain is connected...... to the peptide backbone to provide control of χ(1)- and χ(2)-space. The manifold applications for cyclized analogues of the aromatic amino acids Phe, Tyr, Trp, and His within peptide medicinal chemistry are showcased herein with examples of enzyme inhibitors and ligands for G protein-coupled receptors....

Multi-walled carbon nanotubes (MWCNTs) functionalized with amino groups by reacting with supercritical ammonia fluids

International Nuclear Information System (INIS)

Shao Lu; Bai Yongping; Huang Xu; Gao Zhangfei; Meng Linghui; Huang Yudong; Ma Jun

2009-01-01

For the first time, supercritical ammonia fluid was utilized to simply functionalize multi-walled carbon nanotube (MWCNT) with amino groups. The successful amino functionalization of MWCNTs was proven and the physicochemical properties of MWCNTs before and after supercritical ammonia fluids modifications were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscope (AFM) and Raman spectroscopy. The results also indicated that the supercritical ammonia fluids had the visible effects on the nanostructure of carbon nanotubes. Our novel modification approach provides an easy way to modify MWCNTs with amino groups, which is very useful for realizing 'carbon nanotube economy' in the near future.

13C based proteinogenic amino acid (PAA) and metabolic flux ratio analysis of Lactococcus lactis reveals changes in pentose phosphate (PP) pathway in response to agitation and temperature related stresses.

Science.gov (United States)

Azizan, Kamalrul Azlan; Ressom, Habtom W; Mendoza, Eduardo R; Baharum, Syarul Nataqain

2017-01-01

Lactococcus lactis subsp. cremoris MG1363 is an important starter culture for dairy fermentation. During industrial fermentations, L. lactis is constantly exposed to stresses that affect the growth and performance of the bacterium. Although the response of L. lactis to several stresses has been described, the adaptation mechanisms at the level of in vivo fluxes have seldom been described. To gain insights into cellular metabolism, 13 C metabolic flux analysis and gas chromatography mass spectrometry (GC-MS) were used to measure the flux ratios of active pathways in the central metabolism of L. lactis when subjected to three conditions varying in temperature (30°C, 37°C) and agitation (with and without agitation at 150 rpm). Collectively, the concentrations of proteinogenic amino acids (PAAs) and free fatty acids (FAAs) were compared, and Pearson correlation analysis ( r ) was calculated to measure the pairwise relationship between PAAs. Branched chain and aromatic amino acids, threonine, serine, lysine and histidine were correlated strongly, suggesting changes in flux regulation in glycolysis, the pentose phosphate (PP) pathway, malic enzyme and anaplerotic reaction catalysed by pyruvate carboxylase (pycA). Flux ratio analysis revealed that glucose was mainly converted by glycolysis, highlighting the stability of L. lactis' central carbon metabolism despite different conditions. Higher flux ratios through oxaloacetate (OAA) from pyruvate (PYR) reaction in all conditions suggested the activation of pyruvate carboxylate (pycA) in L. lactis , in response to acid stress during exponential phase. Subsequently, more significant flux ratio differences were seen through the oxidative and non-oxidative pentose phosphate (PP) pathways, malic enzyme, and serine and C1 metabolism, suggesting NADPH requirements in response to environmental stimuli. These reactions could play an important role in optimization strategies for metabolic engineering in L. lactis . Overall, the

13C based proteinogenic amino acid (PAA and metabolic flux ratio analysis of Lactococcus lactis reveals changes in pentose phosphate (PP pathway in response to agitation and temperature related stresses

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Kamalrul Azlan Azizan

2017-07-01

Full Text Available Lactococcus lactis subsp. cremoris MG1363 is an important starter culture for dairy fermentation. During industrial fermentations, L. lactis is constantly exposed to stresses that affect the growth and performance of the bacterium. Although the response of L. lactis to several stresses has been described, the adaptation mechanisms at the level of in vivo fluxes have seldom been described. To gain insights into cellular metabolism, 13C metabolic flux analysis and gas chromatography mass spectrometry (GC-MS were used to measure the flux ratios of active pathways in the central metabolism of L. lactis when subjected to three conditions varying in temperature (30°C, 37°C and agitation (with and without agitation at 150 rpm. Collectively, the concentrations of proteinogenic amino acids (PAAs and free fatty acids (FAAs were compared, and Pearson correlation analysis (r was calculated to measure the pairwise relationship between PAAs. Branched chain and aromatic amino acids, threonine, serine, lysine and histidine were correlated strongly, suggesting changes in flux regulation in glycolysis, the pentose phosphate (PP pathway, malic enzyme and anaplerotic reaction catalysed by pyruvate carboxylase (pycA. Flux ratio analysis revealed that glucose was mainly converted by glycolysis, highlighting the stability of L. lactis’ central carbon metabolism despite different conditions. Higher flux ratios through oxaloacetate (OAA from pyruvate (PYR reaction in all conditions suggested the activation of pyruvate carboxylate (pycA in L. lactis, in response to acid stress during exponential phase. Subsequently, more significant flux ratio differences were seen through the oxidative and non-oxidative pentose phosphate (PP pathways, malic enzyme, and serine and C1 metabolism, suggesting NADPH requirements in response to environmental stimuli. These reactions could play an important role in optimization strategies for metabolic engineering in L. lactis. Overall

13C based proteinogenic amino acid (PAA) and metabolic flux ratio analysis of Lactococcus lactis reveals changes in pentose phosphate (PP) pathway in response to agitation and temperature related stresses

Science.gov (United States)

2017-01-01

Lactococcus lactis subsp. cremoris MG1363 is an important starter culture for dairy fermentation. During industrial fermentations, L. lactis is constantly exposed to stresses that affect the growth and performance of the bacterium. Although the response of L. lactis to several stresses has been described, the adaptation mechanisms at the level of in vivo fluxes have seldom been described. To gain insights into cellular metabolism, 13C metabolic flux analysis and gas chromatography mass spectrometry (GC-MS) were used to measure the flux ratios of active pathways in the central metabolism of L. lactis when subjected to three conditions varying in temperature (30°C, 37°C) and agitation (with and without agitation at 150 rpm). Collectively, the concentrations of proteinogenic amino acids (PAAs) and free fatty acids (FAAs) were compared, and Pearson correlation analysis (r) was calculated to measure the pairwise relationship between PAAs. Branched chain and aromatic amino acids, threonine, serine, lysine and histidine were correlated strongly, suggesting changes in flux regulation in glycolysis, the pentose phosphate (PP) pathway, malic enzyme and anaplerotic reaction catalysed by pyruvate carboxylase (pycA). Flux ratio analysis revealed that glucose was mainly converted by glycolysis, highlighting the stability of L. lactis’ central carbon metabolism despite different conditions. Higher flux ratios through oxaloacetate (OAA) from pyruvate (PYR) reaction in all conditions suggested the activation of pyruvate carboxylate (pycA) in L. lactis, in response to acid stress during exponential phase. Subsequently, more significant flux ratio differences were seen through the oxidative and non-oxidative pentose phosphate (PP) pathways, malic enzyme, and serine and C1 metabolism, suggesting NADPH requirements in response to environmental stimuli. These reactions could play an important role in optimization strategies for metabolic engineering in L. lactis. Overall, the

Amino acid fermentation at the origin of the genetic code

Science.gov (United States)

2012-01-01

There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP) yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can act and refine the assignments

Amino acid fermentation at the origin of the genetic code

Directory of Open Access Journals (Sweden)

de Vladar Harold P

2012-02-01

Full Text Available Abstract There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can

The positive association of branched-chain amino acids and metabolic dyslipidemia in Chinese Han population.

Science.gov (United States)

Yang, Panpan; Hu, Wen; Fu, Zhenzhen; Sun, Luning; Zhou, Ying; Gong, Yingyun; Yang, Tao; Zhou, Hongwen

2016-07-25

It has been suggested that serum branched-chain amino acids (BCAAs) are associated with the incident, progression and prognostic of type 2 diabetes. However, the role of BCAAs in metabolic dyslipidemia (raised triglycerides (TG) and reduced high-density lipoprotein cholesterol (HDL-C)) remains poorly understood. This study aims to investigate 1) the association of serum BCAAs with total cholesterol (TC), TG, HDL-C and low-density lipoprotein cholesterol (LDL-C) and 2) the association between serum BCAAs levels and risk of metabolic dyslipidemia in a community population with different glucose homeostasis. Demographics data and blood samples were collected from 2251 Chinese subjects from the Huaian Diabetes Protective Program (HADPP) study. After exclusion for cardiovascular disease (CVD), serious hepatic or nephritic diseases and others, 1320 subjects remained for analysis (789 subjects with hemoglobin A1c (HbA1c) > 5.7, 521 with HbA1c ≤ 5.7). Serum BCAAs level was measured by liquid chromatography-tandem mass spectrometry (LC MS/MS). The association of BCAAs with lipids or with the risk of metabolic dyslipidemia was analyzed. Elevated serum BCAAs (both total and individual BCAA) were positively associated with TG and inversely associated with HDL-C in the whole population. These correlations were still significant even after adjustment for confounding factors (r = 0.165, p dyslipidemia was 3.703 (2.261, 6.065) and 3.702 (1.877, 7.304), respectively (all p dyslipidemia. In addition, glucose homeostasis could play a certain role in BCAAs-related dyslipidemia.

tRNAs: cellular barcodes for amino acids

DEFF Research Database (Denmark)

Banerjee, Rajat; Chen, Shawn; Dare, Kiley

2010-01-01

The role of tRNA in translating the genetic code has received considerable attention over the last 50 years, and we now know in great detail how particular amino acids are specifically selected and brought to the ribosome in response to the corresponding mRNA codon. Over the same period, it has...... also become increasingly clear that the ribosome is not the only destination to which tRNAs deliver amino acids, with processes ranging from lipid modification to antibiotic biosynthesis all using aminoacyl-tRNAs as substrates. Here we review examples of alternative functions for tRNA beyond...... translation, which together suggest that the role of tRNA is to deliver amino acids for a variety of processes that includes, but is not limited to, protein synthesis....

Biochemical studies on the effect of fluoride on higher plants. I. Metabolism of carbohydrates, organic acids and amino acids. [Glycine max var. Hawkeye

Energy Technology Data Exchange (ETDEWEB)

Yang, S F; Miller, G W

1963-01-01

Metabolic processes associated with free sugars, organic acids and amino acids in higher plants subjected to fluoride fumigation were studied quantitatively. Fluoride-fumigated leaves contained more reducing sugars and less sucrose than the normal leaves. This result suggested inhibition of sucrose synthesis by fluoride. Necrotic leaves contained increased total concentrations of organic acids, which were mostly attributable to malic acid, malonic acid and citric acid. The greater increase in malic acid relative to that of citric acid was the reverse of results observed in chlorotic tissue. Necrotic leaves contained enhanced amounts of free amino acids. The greatest increase occurred in the concentration of asparagine and might be related to the increased respiratory rate of necrotic leaves. Pipecolic acid accumulated in large quantities in nicrotic tissue and was not detected in normal leaves. The accumulation of organic acids and amino acids in leaves during fluoride fumigation was evidenced by a lowered respiratory quotient.

Role of sialic acid in synaptosomal transport of amino acid transmitters

International Nuclear Information System (INIS)

Zaleska, M.M.; Erecinska, M.

1987-01-01

Active, high-affinity, sodium-dependent uptake of [ 14 C]-aminobutyric acid and of the acidic amino acid D-[ 3 H]-aspartate was inhibited by pretreatment of synaptosomes with neuraminidase from Vibrio cholerae. Inhibition was of a noncompetitive type and was related to the amount of sialic acid released. The maximum accumulation ratios of both amino acids (intracellular [amino acid]/extracellular [amino acid]) remained largely unaltered. Treatment with neuraminidase affected neither the synaptosomal energy levels nor the concentration of internal potassium. It is suggested that the γ-aminobutyric acid and acidic amino acid transporters are glycosylated and that sialic acid is involved in the operation of the carrier proteins directly and not through modification of driving forces responsible for amino acid uptake

Forced swimming and imipramine modify plasma and brain amino acid concentrations in mice.

Science.gov (United States)

Murakami, Tatsuro; Yamane, Haruka; Tomonaga, Shozo; Furuse, Mitsuhiro

2009-01-05

The relationships between monoamine metabolism and forced swimming or antidepressants have been well studied, however information is lacking regarding amino acid metabolism under these conditions. Therefore, the aim of the present study was to investigate the effects of forced swimming and imipramine on amino acid concentrations in plasma, the cerebral cortex and the hypothalamus in mice. Forced swimming caused cerebral cortex concentrations of L-glutamine, L-alanine, and taurine to be increased, while imipramine treatment caused decreased concentrations of L-glutamate, L-alanine, L-tyrosine, L-methionine, and L-ornithine. In the hypothalamus, forced swimming decreased the concentration of L-serine while imipramine treatment caused increased concentration of beta-alanine. Forced swimming caused increased plasma concentration of taurine, while concentrations of L-serine, L-asparagine, L-glutamine and beta-alanine were decreased. Imipramine treatment caused increased plasma concentration of all amino acid, except for L-aspartate and taurine. In conclusion, forced swimming and imipramine treatment modify central and peripheral amino acid metabolism. These results may aid in the identification of amino acids that have antidepressant-like effects, or may help to refine the dosages of antidepressant drugs.

A Three-Ring Circus: Metabolism of the Three Proteogenic Aromatic Amino Acids and Their Role in the Health of Plants and Animals

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Parthasarathy, Anutthaman; Cross, Penelope J.; Dobson, Renwick C. J.; Adams, Lily E.; Savka, Michael A.; Hudson, André O.

2018-01-01

Tyrosine, phenylalanine and tryptophan are the three aromatic amino acids (AAA) involved in protein synthesis. These amino acids and their metabolism are linked to the synthesis of a variety of secondary metabolites, a subset of which are involved in numerous anabolic pathways responsible for the synthesis of pigment compounds, plant hormones and biological polymers, to name a few. In addition, these metabolites derived from the AAA pathways mediate the transmission of nervous signals, quench reactive oxygen species in the brain, and are involved in the vast palette of animal coloration among others pathways. The AAA and metabolites derived from them also have integral roles in the health of both plants and animals. This review delineates the de novo biosynthesis of the AAA by microbes and plants, and the branching out of AAA metabolism into major secondary metabolic pathways in plants such as the phenylpropanoid pathway. Organisms that do not possess the enzymatic machinery for the de novo synthesis of AAA must obtain these primary metabolites from their diet. Therefore, the metabolism of AAA by the host animal and the resident microflora are important for the health of all animals. In addition, the AAA metabolite-mediated host-pathogen interactions in general, as well as potential beneficial and harmful AAA-derived compounds produced by gut bacteria are discussed. Apart from the AAA biosynthetic pathways in plants and microbes such as the shikimate pathway and the tryptophan pathway, this review also deals with AAA catabolism in plants, AAA degradation via the monoamine and kynurenine pathways in animals, and AAA catabolism via the 3-aryllactate and kynurenine pathways in animal-associated microbes. Emphasis will be placed on structural and functional aspects of several key AAA-related enzymes, such as shikimate synthase, chorismate mutase, anthranilate synthase, tryptophan synthase, tyrosine aminotransferase, dopachrome tautomerase, radical dehydratase, and type

Effects of Peptone Supplementation in Different Culture Media on Growth, Metabolic Pathway and Productivity of CHO DG44 Cells; a New Insight into Amino Acid Profiles.

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Davami, Fatemeh; Eghbalpour, Farnaz; Nematollahi, Leila; Barkhordari, Farzaneh; Mahboudi, Fereidoun

2015-01-01

The optimization of bioprocess conditions towards improved growth profile and productivity yield is considered of great importance in biopharmaceutical manufacturing. Peptones as efficient sources of nutrients have been studied for their effect on media development; however, their role on metabolic pathway is not well understood. In the present study, the effect of different concentration of peptones on a recombinant Chinese hamster ovary (CHO) cell line grown in three serum-free suspension cultures was determined. Six peptones of different origins and available amino acid profiles were investigated regarding their impact on cell growth, productivity, and metabolic pathways changes. In optimized feeding strategies, increases of 136% and 159% in volumetric productivity (for a low-nutrient culture media) and 55% (for a high-nutrient culture media) were achieved. Furthermore, particular sources of peptones with specific amino acid profile developed preferential results for each different culture medium. Two peptones, SoyA2SC and SoyE-110, were the only hydrolysates that showed production improvement in all three media. Casein Peptone plus Tryptone N1 and SoyA3SC showed different improved results based on their implemented concentration for each individual basal medium. The amino acid profile of peptones may provide clues to identify the most effective feeding strategies for recombinant CHO cells.

Identification of Important Amino Acids in Gal2p for Improving the L-arabinose Transport and Metabolism in Saccharomyces cerevisiae

Directory of Open Access Journals (Sweden)

Chengqiang Wang

2017-07-01

Full Text Available Efficient and cost-effective bioethanol production from lignocellulosic materials requires co-fermentation of the main hydrolyzed sugars, including glucose, xylose, and L-arabinose. Saccharomyces cerevisiae is a glucose-fermenting yeast that is traditionally used for ethanol production. Fermentation of L-arabinose is also possible after metabolic engineering. Transport into the cell is the first and rate-limiting step for L-arabinose metabolism. The galactose permease, Gal2p, is a non-specific, endogenous monosaccharide transporter that has been shown to transport L-arabinose. However, Gal2p-mediated transport of L-arabinose occurs at a low efficiency. In this study, homologous modeling and L-arabinose docking were used to predict amino acids in Gal2p that are crucial for L-arabinose transport. Nine amino acid residues in Gal2p were identified and were the focus for site-directed mutagenesis. In the Gal2p transport-deficient chassis cells, the capacity for L-arabinose transport of the different Gal2p mutants was compared by testing growth rates using L-arabinose as the sole carbon source. Almost all the tested mutations affected L-arabinose transport capacity. Among them, F85 is a unique site. The F85S, F85G, F85C, and F85T point mutations significantly increased L-arabinose transport activities, while, the F85E and F85R mutations decreased L-arabinose transport activities compared to the Gal2p-expressing wild-type strain. These results verified F85 as a key residue in L-arabinose transport. The F85S mutation, having the most significant effect, elevated the exponential growth rate by 40%. The F85S mutation also improved xylose transport efficiency and weakened the glucose transport preference. Overall, enhancing the L-arabinose transport capacity further improved the L-arabinose metabolism of engineered S. cerevisiae.

The Complex Role of Branched Chain Amino Acids in Diabetes and Cancer

OpenAIRE

O’Connell, Thomas M.

2013-01-01

The obesity and diabetes epidemics are continuing to spread across the globe. There is increasing evidence that diabetes leads to a significantly higher risk for certain types of cancer. Both diabetes and cancer are characterized by severe metabolic perturbations and the branched chain amino acids (BCAAs) appear to play a significant role in both of these diseases. These essential amino acids participate in a wide variety of metabolic pathways, but it is now recognized that they are also crit...

Branched-Chain Amino Acid Negatively Regulates KLF15 Expression via PI3K-AKT Pathway

OpenAIRE

Yunxia Liu; Weibing Dong; Jing Shao; Yibin Wang; Meiyi Zhou; Haipeng Sun

2017-01-01

Recent studies have linked branched-chain amino acid (BCAA) with numerous metabolic diseases. However, the molecular basis of BCAA's roles in metabolic regulation remains to be established. KLF15 (Krüppel-like factor 15) is a transcription factor and master regulator of glycemic, lipid, and amino acids metabolism. In the present study, we found high concentrations of BCAA suppressed KLF15 expression while BCAA starvation induced KLF15 expression, suggesting KLF15 expression is negatively cont...

Lipidization of Simple and di-Functional Amino Acids

International Nuclear Information System (INIS)

Zainab Idris; Mohd Wahid Samsudin; Salmiah Ahmad

2013-01-01

This paper discuss the modification of azelaic acid into its applicable form by attachment of both its carboxyl sites to N-terminal of amino acid ethyl ester forming amide linkages in anhydrous medium. Acylation of glycine ethyl ester hydrochloride with azelaic acid dichloride was best conducted in a 100 % anhydrous medium. L-amino acid ethyl ester bearing a primary hydroxyl group on its side chain gave mixtures of product and variation in composition depending on the mole ratio of reactants used. Reduction in purity was also observed for L-amino acid ethyl ester with primary -SH group on its side chain as compared to L-amino acid ethyl ester having -SCH 3 group on the L-amino acid side chain. The diamidoester of azelaic acid with L-alanine ethyl ester, L-valine ethyl ester, L-leucine ethyl ester and L-glutamic acid diethyl ester were in good yield when prepared through the modified Schotten-Baumann reaction conditions. (author)

Functional Modification of Thioether Groups in Peptides, Polypeptides, and Proteins

OpenAIRE

Deming, TJ

2017-01-01

Recent developments in the modification of methionine and other thioether-containing residues in peptides, polypeptides, and proteins are reviewed. Properties and potential applications of the resulting functionalized products are also discussed. While much of this work is focused on natural Met residues, modifications at other side-chain residues have also emerged as new thioether-containing amino acids have been incorporated into peptidic materials. Functional modification of thioether-cont...

Amino acid and glucose metabolism in fed-batch CHO cell culture affects antibody production and glycosylation.

Science.gov (United States)

Fan, Yuzhou; Jimenez Del Val, Ioscani; Müller, Christian; Wagtberg Sen, Jette; Rasmussen, Søren Kofoed; Kontoravdi, Cleo; Weilguny, Dietmar; Andersen, Mikael Rørdam

2015-03-01

Fed-batch Chinese hamster ovary (CHO) cell culture is the most commonly used process for IgG production in the biopharmaceutical industry. Amino acid and glucose consumption, cell growth, metabolism, antibody titer, and N-glycosylation patterns are always the major concerns during upstream process optimization, especially media optimization. Gaining knowledge on their interrelations could provide insight for obtaining higher immunoglobulin G (IgG) titer and better controlling glycosylation-related product quality. In this work, different fed-batch processes with two chemically defined proprietary media and feeds were studied using two IgG-producing cell lines. Our results indicate that the balance of glucose and amino acid concentration in the culture is important for cell growth, IgG titer and N-glycosylation. Accordingly, the ideal fate of glucose and amino acids in the culture could be mainly towards energy and recombinant product, respectively. Accumulation of by-products such as NH4(+) and lactate as a consequence of unbalanced nutrient supply to cell activities inhibits cell growth. The levels of Leu and Arg in the culture, which relate to cell growth and IgG productivity, need to be well controlled. Amino acids with the highest consumption rates correlate with the most abundant amino acids present in the produced IgG, and thus require sufficient availability during culture. Case-by-case analysis is necessary for understanding the effect of media and process optimization on glycosylation. We found that in certain cases the presence of Man5 glycan can be linked to limitation of UDP-GlcNAc biosynthesis as a result of insufficient extracellular Gln. However, under different culture conditions, high Man5 levels can also result from low α-1,3-mannosyl-glycoprotein 2-β-N-acetylglucosaminyltransferase (GnTI) and UDP-GlcNAc transporter activities, which may be attributed to high level of NH4+ in the cell culture. Furthermore, galactosylation of the mAb Fc glycans

Branched-Chain Amino Acid Levels Are Related with Surrogates of Disturbed Lipid Metabolism among Older Men

Directory of Open Access Journals (Sweden)

Urho M Kujala

2016-11-01

Full Text Available Aims/hypothesis Existing studies suggest that decreased branched-chain amino acid (BCAA catabolism and thus elevated levels in blood are associated with metabolic disturbances. Based on such information we have developed a hypothesis how BCAA degradation mechanistically connects to tricarboxylic acid (TCA cycle, intramyocellular lipid storage and oxidation thus allowing more efficient mitochondrial energy production from lipids as well as providing better metabolic health. We analyzed whether data from aged Finnish men are in line with our mechanistic hypothesis linking BCAA catabolism and metabolic disturbances. Methods Older Finnish men enriched with individuals having been athletes in young adulthood (n=593; mean age 72.6 ± 5.9 years responded to questionnaires, participated in a clinical examination including assessment of body composition with bioimpedance and gave fasting blood samples for various analytes as well as participated in a 2 hour 75 g oral glucose tolerance test. Metabolomics measurements from serum included BCAAs (isoleucine, leucine and valine.Results Out of the 593 participants 59 had previously known type 2 diabetes, further 67 had screen-detected type 2 diabetes, 127 IGT and 125 IFG while 214 had normal glucose regulation. There were group differences in all of the BCAA concentrations (p≤0.005 for all BCAAs, such that those with normal glucose tolerance had the lowest and those with diabetes mellitus had the highest BCAA concentrations. All BCAA levels correlated positively with body fat percentage (r=.29 - .34, p<.0001 for all. Expected associations with high BCAA concentrations and unfavorable metabolic profile indicators from metabolomics analysis were found. Except for glucose concentrations, the associations were stronger with isoleucine and leucine than with valine. Conclusions/interpretation The findings provided further support for our hypothesis by strengthening the idea that the efficiency of BCAA catabolism

The Role of Amino Acids in Gluconeogenesis in Lactating Ruminants

Energy Technology Data Exchange (ETDEWEB)

Black, A. L.; Egan, A. R.; Anand, R. S.; Chapman, T. E. [Department of Physiological Sciences, School of Veterinary Medicine, University of California, Davis, CA (United States)

1968-07-01

Gluconeogenesis has an important metabolic role in all animals, but it is especially important in ruminants because of the paucity of their alimentary glucose. Several amino acids give rise to glucogenic precursors during metabolism and thus dietary or body protein represents an important source of potential glucogenic material that the ruminant can utilize to manufacture the glucose required for its physiological functions. The role of various amino acids as glucose precursors has been evaluated in lactating ruminants by making a single intravenous injection of several different amino acids uniformly labelled with {sup 14}C and following, with time, the rate and extent of incorporation of {sup 14}C into the plasma glucose. The time interval after injecting each {sup 14}C-amino acid until the specific activity maximum occurred in plasma glucose was found to vary widely among the different amino acids. Thus, the maximum specific activity in plasma glucose occurred 6 min after injection of L-aspartate-{sup 14}C and 15 min after injection of L-glutamate- {sup 14}C, while for L-valine-{sup 14}C and L-arginine-{sup 14}C the maximum specific activity in plasma glucose did not occur until 45 and 90 min, respectively, had elapsed. After injection of L-serine and L-alanine there were several maxima in the glucose specific activity. These maxima occurred between 12 and 24 min after injection of serine and during the first 30 min after injection of alanine indicating that carbon from these amino acids becomes available for glucose synthesis along diverse pathways which have different delays. Although only a few amino acids have been studied, the experimental results obtained clearly suggest an important metabolic role for protein in ruminants which has previously not been recognized. It appears that amino acids, released from protein, are utilized by the animal in a fashion which results in a prolonged availability of glucogenic precursors so that the animal can form glucose

Functional genomics of lipid metabolism in the oleaginous yeast Rhodosporidium toruloides

Science.gov (United States)

Geiselman, Gina M; Ito, Masakazu; Mondo, Stephen J; Reilly, Morgann C; Cheng, Ya-Fang; Bauer, Stefan; Grigoriev, Igor V; Gladden, John M; Simmons, Blake A; Brem, Rachel B

2018-01-01

The basidiomycete yeast Rhodosporidium toruloides (also known as Rhodotorula toruloides) accumulates high concentrations of lipids and carotenoids from diverse carbon sources. It has great potential as a model for the cellular biology of lipid droplets and for sustainable chemical production. We developed a method for high-throughput genetics (RB-TDNAseq), using sequence-barcoded Agrobacterium tumefaciens T-DNA insertions. We identified 1,337 putative essential genes with low T-DNA insertion rates. We functionally profiled genes required for fatty acid catabolism and lipid accumulation, validating results with 35 targeted deletion strains. We identified a high-confidence set of 150 genes affecting lipid accumulation, including genes with predicted function in signaling cascades, gene expression, protein modification and vesicular trafficking, autophagy, amino acid synthesis and tRNA modification, and genes of unknown function. These results greatly advance our understanding of lipid metabolism in this oleaginous species and demonstrate a general approach for barcoded mutagenesis that should enable functional genomics in diverse fungi. PMID:29521624

Second-tier test for quantification of underivatized amino acids in dry blood spot for metabolic diseases in newborn screening.

Science.gov (United States)

Wang, Chunyan; Zhu, Hongbin; Zhang, Wenyan; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

2013-02-01

The quantitative analysis of amino acids (AAs) in single dry blood spot (DBS) samples is an important issue for metabolic diseases as a second-tier test in newborn screening. An analytical method for quantifying underivatized AAs in DBS was developed by using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The sample preparation in this method is simple and ion-pairing agent is not used in the mobile phase that could avoid ion suppression, which happens in mass spectrometry and avoids damage to the column. Through chromatographic separation, some isomeric compounds could be identified and quantified, which cannot be solved through only appropriate multiple reactions monitoring transitions by MS/MS. The concentrations of the different AAs were determined using non-deuterated internal standard. All calibration curves showed excellent linearity within test ranges. For most of the amino acids the accuracy of extraction recovery was between 85.3 and 115 %, and the precision of relative standard deviation was <7.0 %. The 35 AAs could be identified in DBS specimens by the developed LC-MS/MS method in 17-19 min, and eventually 24 AAs in DBS were quantified. The results of the present study prove that this method as a second-tier test in newborn screening for metabolic diseases could be performed by the quantification of free AAs in DBS using the LC-MS/MS method. The assay has advantages of high sensitive, specific, and inexpensive merits because non-deuterated internal standard and acetic acid instead of ion-pairing agent in mobile phase are used in this protocol.

Glutaminolysis: A Hallmark of Cancer Metabolism.

Science.gov (United States)

Yang, Lifeng; Venneti, Sriram; Nagrath, Deepak

2017-06-21

Glutamine is the most abundant circulating amino acid in blood and muscle and is critical for many fundamental cell functions in cancer cells, including synthesis of metabolites that maintain mitochondrial metabolism; generation of antioxidants to remove reactive oxygen species; synthesis of nonessential amino acids (NEAAs), purines, pyrimidines, and fatty acids for cellular replication; and activation of cell signaling. In light of the pleiotropic role of glutamine in cancer cells, a comprehensive understanding of glutamine metabolism is essential for the development of metabolic therapeutic strategies for targeting cancer cells. In this article, we review oncogene-, tumor suppressor-, and tumor microenvironment-mediated regulation of glutamine metabolism in cancer cells. We describe the mechanism of glutamine's regulation of tumor proliferation, metastasis, and global methylation. Furthermore, we highlight the therapeutic potential of glutamine metabolism and emphasize that clinical application of in vivo assessment of glutamine metabolism is critical for identifying new ways to treat patients through glutamine-based metabolic therapy.

Proteomic analysis of the cyanobacterium of the Azolla symbiosis: identity, adaptation, and NifH modification.

Science.gov (United States)

Ekman, Martin; Tollbäck, Petter; Bergman, Birgitta

2008-01-01

Cyanobacteria are able to form stable nitrogen-fixing symbioses with diverse eukaryotes. To extend our understanding of adaptations imposed by plant hosts, two-dimensional gel electrophoresis and mass spectrometry (MS) were used for comparative protein expression profiling of a cyanobacterium (cyanobiont) dwelling in leaf cavities of the water-fern Azolla filiculoides. Homology-based protein identification using peptide mass fingerprinting [matrix-assisted laser desorption ionization-time of flight (MALDI-TOF-MS)], tandem MS analyses, and sequence homology searches resulted in an identification success rate of 79% of proteins analysed in the unsequenced cyanobiont. Compared with a free-living strain, processes related to energy production, nitrogen and carbon metabolism, and stress-related functions were up-regulated in the cyanobiont while photosynthesis and metabolic turnover rates were down-regulated, stressing a slow heterotrophic mode of growth, as well as high heterocyst frequencies and nitrogen-fixing capacities. The first molecular data set on the nature of the NifH post-translational modification in cyanobacteria was also obtained: peptide mass spectra of the protein demonstrated the presence of a 300-400 Da protein modification localized to a specific 13 amino acid sequence, within the part of the protein that is ADP-ribosylated in other bacteria and close to the active site of nitrogenase. Furthermore, the distribution of the highest scoring database hits for the identified proteins points to the possibility of using proteomic data in taxonomy.

Radiolabeled hydroxamate-based matrix metalloproteinase inhibitors: How chemical modifications affect pharmacokinetics and metabolic stability

International Nuclear Information System (INIS)

Hugenberg, Verena; Hermann, Sven; Galla, Fabian; Schäfers, Michael

2016-01-01

Introduction: Dysregulated MMP expression or activation is associated with several diseases. To study MMP activity in vivo by means of PET a radiolabeled MMP inhibitor (MMPI) functioning as radiotracer has been developed by our group based on the lead structure CGS 25966. Materials and methods: Aiming at the modification of the pharmacokinetics of this lipophilic model tracer a new class of MMPIs has been discovered, consisting of additional fluorinated hydrophilic substructures, such as mini-PEG and/or 1,2,3-triazole units. To identify the best candidate for further clinical applications, radiofluorinated compounds of each subgroup have been (radio) synthesized and evaluated regarding their biodistribution behavior and their metabolic stability. Results: Radiosyntheses of different triazole based MMPIs could be realized using two step “click chemistry” procedures. Compared to lead structure [ 18 F]FEtO-CGS 25966 ([ 18 F]1e, log D(exp) = 2.02, IC 50 = 2–50 nM) all selected candidates showed increased hydrophilicities and inhibition potencies (log D(exp) = 0.23–1.25, IC 50 = 0.006–6 nM). Interestingly, despite different hydrophilicities most triazole based MMPIs showed no significant differences in their in vivo biodistribution behavior and were cleared predominantly via the hepatobiliary excretion route. Biostability and metabolism studies in vitro and in vivo revealed significant higher metabolic stability for the triazole moiety compared to the benzyl ring in the lead structure. Cleavage of ethylene glycol subunits of the mini-PEG chain led to a faster metabolism of mini-PEG containing MMPIs. Conclusion: The introduction of hydrophilic groups such as mini-PEG and 1,2,3-triazole units did not lead to a significant shift of the hepatobiliary elimination towards renal clearance. Particularly the introduction of mini-PEG chains led to an intense metabolic decomposition. Substitution of the benzyl moiety in lead structure 1e by a 1,2,3-trizole ring resulted

Effects of squat exercise and branched-chain amino acid supplementation on plasma free amino acid concentrations in young women.

Science.gov (United States)

Shimomura, Yoshiharu; Kobayashi, Hisamine; Mawatari, Kazunori; Akita, Keiichi; Inaguma, Asami; Watanabe, Satoko; Bajotto, Gustavo; Sato, Juichi

2009-06-01

The present study was conducted to examine alterations in plasma free amino acid concentrations induced by squat exercise and branched-chain amino acid (BCAA) supplementation in young, untrained female subjects. In the morning on the exercise session day, participants ingested drinks containing either BCAA (isoleucine:leucine:valine=1:2.3:1.2) or dextrin (placebo) at 0.1 g/kg body weight 15 min before a squat exercise session, which consisted of 7 sets of 20 squats, with 3 min intervals between sets. In the placebo trial, plasma BCAA concentrations were decreased subsequent to exercise, whereas they were significantly increased in the BCAA trial until 2 h after exercise. Marked changes in other free amino acids in response to squat exercise and BCAA supplementation were observed. In particular, plasma concentrations of methionine and aromatic amino acids were temporarily decreased in the BCAA trial, being significantly lower than those in the placebo trial. These results suggest that BCAA intake before exercise affects methionine and aromatic amino acid metabolism.

Metabolic rates of 15N-D- and 15N-L-phenylalanine in an amino acid mixture for parenteral feeding

International Nuclear Information System (INIS)

Wutzke, K.; Heine, W.; Drescher, U.

1982-01-01

15 N investigations on the metabolism of L- and D-phenylalanine under conditions of parenteral feeding with the aminoacid solution Infesol in 6 infants revealed a retention rate of 83.4 +- 3.4 per cent for the L-form and of 36.6 +- 5.2 per cent for the D-form. When the D-isomer was raised from 1:3 to 1:1 in relation to the L-Form, 32.6 per cent of the infused D-phenylalanine were still retained. After continuous 24-hour infusion of the tracers, the maximum of 15 N excretion in the urine was reached between the 24th and the 30th hour. But little incorporation of 15 N-nitrogen was found in the serum and erythrocytes because of the relatively long half-life period of these proteins. Changes in the composition of commercial DL-amino acid mixtures will only be possible after determining the utilization rates of all essential and non-essential D-amino acids being used in such mixtures. (author)

Regulation of autophagy by amino acids and MTOR-dependent signal transduction.

Science.gov (United States)

Meijer, Alfred J; Lorin, Séverine; Blommaart, Edward F; Codogno, Patrice

2015-10-01

Amino acids not only participate in intermediary metabolism but also stimulate insulin-mechanistic target of rapamycin (MTOR)-mediated signal transduction which controls the major metabolic pathways. Among these is the pathway of autophagy which takes care of the degradation of long-lived proteins and of the elimination of damaged or functionally redundant organelles. Proper functioning of this process is essential for cell survival. Dysregulation of autophagy has been implicated in the etiology of several pathologies. The history of the studies on the interrelationship between amino acids, MTOR signaling and autophagy is the subject of this review. The mechanisms responsible for the stimulation of MTOR-mediated signaling, and the inhibition of autophagy, by amino acids have been studied intensively in the past but are still not completely clarified. Recent developments in this field are discussed.

Role of amino acids and vitamins in nutrition of mesophilic Methanococcus spp

International Nuclear Information System (INIS)

Whitman, W.B.; Sohn, S.; Kuk, S.; Xing, R.

1987-01-01

In this study the authors found that autotrophic methanococci similar to Methanococcus maripaludis obtained up to 57% of their cellular carbon from exogeneous amino acids. About 85% of the incorporation was into protein. Primarily nonpolar and basic amino acids and glycine were incorporated; only small amounts of acidic and some polar amino acids were taken up. An additional 10% of the incorporation was into the nucleic acid fraction. Because little 14 CO 2 was formed from the 14 C-amino acids, little metabolism of the amino acids occurred. Therefore, the growth stimulation by amino acids was probably due to the sparing of anabolic energy requirements. Of the amino acids incorporated, only alanine was also a sole nitrogen source for these methanococci. In contrast, Methanococcus vannielii and Methanococcus aeolicus are autotrophic methanococci which did not incorporate amino acids and did not utilize alanine as a sole nitrogen source. Although glutamine served as a sole nitrogen source for the autotrophic methanococci and Methanococcus voltae, a heterotrophic methanococcus, growth was due to chemical deamination in the medium. M. voltae requires leucine and isoleucine for growth. However, these amino acids were not significant nitrogen sources, and alanine was not a sole nitrogen source for the growth of M. voltae. The branched-chain amino acids were not extensively metabolized by M. voltae. Pantoyl lactone and pantoic acid were readily incorporated by M. voltae. The intact vitamin pantothenate was neither stimulatory to growth nor incorporated. In conclusion, although amino acids and vitamins are nutritionally important to both autotrophic and heterotrophic methanococci, generally they are not subject to extensive catabolism

Glucagon and Amino Acids Are Linked in a Mutual Feedback Cycle

DEFF Research Database (Denmark)

Holst, Jens J; Wewer Albrechtsen, Nicolai J; Pedersen, Jens

2017-01-01

; neither condition is necessarily associated with disturbed glucose metabolism. In glucagonoma patients, amino acid turnover and ureagenesis are greatly accelerated, and low plasma amino acid levels are probably at least partly responsible for the necrolytic migratory erythema, which resolves after amino...... acid administration. In patients with receptor mutations (and in knockout mice), pancreatic swelling is due to α-cell hyperplasia with gross hypersecretion of glucagon, which according to recent groundbreaking research may result from elevated amino acid levels. Additionally, solid evidence indicates...... that ureagenesis, and thereby amino acid levels, is critically controlled by glucagon. Together, this constitutes a complete endocrine system; feedback regulation involving amino acids regulates α-cell function and secretion, while glucagon, in turn, regulates amino acid turnover....

The Role of Circulating Amino Acids in the Hypothalamic Regulation of Liver Glucose Metabolism123

Science.gov (United States)

Arrieta-Cruz, Isabel; Gutiérrez-Juárez, Roger

2016-01-01

A pandemic of diabetes and obesity has been developing worldwide in close association with excessive nutrient intake and a sedentary lifestyle. Variations in the protein content of the diet have a direct impact on glucose homeostasis because amino acids (AAs) are powerful modulators of insulin action. In this work we review our recent findings on how elevations in the concentration of the circulating AAs leucine and proline activate a metabolic mechanism located in the mediobasal hypothalamus of the brain that sends a signal to the liver via the vagus nerve, which curtails glucose output. This neurogenic signal is strictly dependent on the metabolism of leucine and proline to acetyl-coenzyme A (CoA) and the subsequent production of malonyl-CoA; the signal also requires functional neuronal ATP-sensitive potassium channels. The liver then responds by lowering the rate of gluconeogenesis and glycogenolysis, ultimately leading to a net decrease in glucose production and in concentrations of circulating glucose. Furthermore, we review here how our work with proline suggests a new role of astrocytes in the central regulation of glycemia. Last, we outline how factors such as the consumption of fat-rich diets can interfere with glucoregulatory mechanisms and, in the long term, may contribute to the development of hyperglycemia, a hallmark of type 2 diabetes. PMID:27422516

Regulation of autophagy by amino acids and MTOR-dependent signal transduction

NARCIS (Netherlands)

Meijer, Alfred J.; Lorin, Séverine; Blommaart, Edward F.; Codogno, Patrice

2015-01-01

Amino acids not only participate in intermediary metabolism but also stimulate insulin-mechanistic target of rapamycin (MTOR)-mediated signal transduction which controls the major metabolic pathways. Among these is the pathway of autophagy which takes care of the degradation of long-lived proteins

Determination of Selected Amino Acids in Serum of Patients with Liver Disease.

Science.gov (United States)

Kanďár, Roman; Drábková, Petra; Toiflová, Tereza; Čegan, Alexander

2016-01-01

The determination of amino acids can be a reliable approach for extended diagnosis of liver diseases. This is because liver disease can be a cause of impaired amino acid metabolism. Therefore, a method for the determination of serum amino acids, applicable for clinical purposes, is necessary. The aim of this study was to find differences in the levels of selected amino acids between patients with liver disease and a control group. Samples of peripheral venous blood were obtained from a group of patients with liver disease (n = 131, 59 women at an average age of 60 years and 72 men at an average age of 52 years) and a control group (n = 105, 47 women at an average age of 62 years and 58 men at an average age of 58 years). Before the separation, the amino acids were derivatized with naphthalene-2,3-dicarboxaldehyde. For the separation, reverse phase column was used. The effluent was monitored with a fluorescence detector. There were significant differences in the concentrations of some amino acids between the patients and the control group, but also between women and men. Correlations between some amino acids and markers of liver blood tests and lipid metabolism were observed. A simple, relatively rapid and selective HPLC method with fluorescence detection for the determination of selected amino acids in serum has been developed.

Chemical modification of b-lactoglobulin by quinones

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DUSAN SLADIC

2003-05-01

Full Text Available The avarone/avarol quinone/hydroquinone couple, as well as their derivatives show considerable antitumor activity. In this work, covalent modifications of b-lactoglobulin, isolated from cow milk, by avarone, its model compound 2-tert-butyl-1,4-benzoquinone, and several of their alkylthio derivatives were studied. The techniques applied for assaying the modifications were: UV/VIS spectrophotometry, SDS PAGE and isoelectrofocusing. The results of the SDS PAGE suggest that polymerisation of the protein occurs. The shift of the pI of the protein upon modification toward lower values indicates that lysine amino groups are the principal site of the reaction of b-lactoglobulin with the quinones.

Metabolic profiling reveals ethylene mediated metabolic changes and a coordinated adaptive mechanism of 'Jonagold' apple to low oxygen stress.

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Bekele, Elias A; Beshir, Wasiye F; Hertog, Maarten L A T M; Nicolai, Bart M; Geeraerd, Annemie H

2015-11-01

Apples are predominantly stored in controlled atmosphere (CA) storage to delay ripening and prolong their storage life. Profiling the dynamics of metabolic changes during ripening and CA storage is vital for understanding the governing molecular mechanism. In this study, the dynamics of the primary metabolism of 'Jonagold' apples during ripening in regular air (RA) storage and initiation of CA storage was profiled. 1-Methylcyclopropene (1-MCP) was exploited to block ethylene receptors and to get insight into ethylene mediated metabolic changes during ripening of the fruit and in response to hypoxic stress. Metabolic changes were quantified in glycolysis, the tricarboxylic acid (TCA) cycle, the Yang cycle and synthesis of the main amino acids branching from these metabolic pathways. Partial least square discriminant analysis of the metabolic profiles of 1-MCP treated and control apples revealed a metabolic divergence in ethylene, organic acid, sugar and amino acid metabolism. During RA storage at 18°C, most amino acids were higher in 1-MCP treated apples, whereas 1-aminocyclopropane-1-carboxylic acid (ACC) was higher in the control apples. The initial response of the fruit to CA initiation was accompanied by an increase of alanine, succinate and glutamate, but a decline in aspartate. Furthermore, alanine and succinate accumulated to higher levels in control apples than 1-MCP treated apples. The observed metabolic changes in these interlinked metabolites may indicate a coordinated adaptive strategy to maximize energy production. © 2015 Scandinavian Plant Physiology Society.

Metabolism of Seriola lalandi during Starvation as Revealed by Fatty Acid Analysis and Compound-Specific Analysis of Stable Isotopes within Amino Acids.

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Fernando Barreto-Curiel

Full Text Available Fish starvation is defined as food deprivation for a long period of time, such that physiological processes become confined to basal metabolism. Starvation provides insights in physiological processes without interference from unknown factors in digestion and nutrient absorption occurring in fed state. Juveniles of amberjack Seriola lalandi were isotopically equilibrated to a formulated diet for 60 days. One treatment consisted of fish that continued to be fed and fish in the other treatment were not fed for 35 days. The isotopic signatures prior to the beginning of and after the starvation period, for fish in the starvation and control treatments, were analysed for lipid content, fatty acid composition and isotopic analysis of bulk (EA-IRMS and of amino acids (compound specific isotope analysis, CSIA. There were three replicates for the starvation group. Fatty acid content in muscle and liver tissue before and after starvation was determined to calculate percent change. Results showed that crude lipid was the most used source of energy in most cases; the PUFAs and LC-PUFAs were highly conserved. According to the protein signature in bulk (δ15N and per amino acid (δ13C and δ15N, in muscle tissue, protein synthesis did not appear to occur substantially during starvation, whereas in liver, increases in δ13C and δ15N indicate that protein turnover occurred, probably for metabolic routing to energy-yielding processes. As a result, isotopic values of δ15N in muscle tissue do not change, whereas CSIA net change occurred in the liver tissue. During the study period of 35 days, muscle protein was largely conserved, being neither replenished from amino acid pools in the plasma and liver nor catabolized.

Whole-body nitrogen and tyrosine metabolism in surgical patients receiving branched-chain amino acid solutions

International Nuclear Information System (INIS)

Desai, S.P.; Bistrian, B.R.; Moldawer, L.L.; Blackburn, G.L.

1985-01-01

Fifteen patients undergoing gastric bypass surgery for morbid obesity received preoperatively a standard crystalline amino acid solution containing 15.6% branched-chain amino acids. During the first five postoperative days, the patients were randomized to receive one of three amino acid solutions of different branched-chain amino acid content. Whole-body amino acid appearance and oxidation were estimated using a continuous intravenous infusion of L-(U- 14 C)-tyrosine preoperatively and on the third postoperative day. This study suggests that an adequate nitrogen intake of a balanced amino acid mixture, as well as a solution enriched with branched-chain amino acids, maintains protein homeostasis and supports protein synthesis similarly in well-nourished patients following major abdominal surgery. A diet containing only branched-chain amino acids in isomolar ratios was as effective at maintaining protein retention and whole-body protein synthesis and albumin renewal postoperatively when compared with a standard amino acid formula

Skeletal muscle metabolism in hypokinetic rats

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Tischler, Marc E.

1993-01-01

This grant focused on the mechanisms of metabolic changes associated with unweighting atrophy and reduced growth of hind limb muscles of juvenile rats. Metabolic studies included a number of different areas. Amino acid metabolic studies placed particular emphasis on glutamine and branched-chain amino acid metabolism. These studies were an outgrowth of understanding stress effects and the role of glucocorticoids in these animals. Investigations on protein metabolism were largely concerned with selective loss of myofibrillar proteins and the role of muscle proteolysis. These investigations lead to finding important differences from denervation and atrophy and to define the roles of cytosolic versus lysosomal proteolysis in these atrophy models. A major outgrowth of these studies was demonstrating an ability to prevent atrophy of the unweighted muscle for at least 24 hours. A large amount of work concentrated on carbohydrate metabolism and its regulation by insulin and catecholamines. Measurements focused on glucose transport, glycogen metabolism, and glucose oxidation. The grant was used to develop an important new in situ approach for studying protein metabolism, glucose transport, and hormonal effects which involves intramuscular injection of various agents for up to 24 hours. Another important consequence of this project was the development and flight of Physiological-Anatomical Rodent Experiment-1 (PARE-1), which was launched aboard Space Shuttle Discovery in September 1991. Detailed descriptions of these studies can be found in the 30 peer-reviewed publications, 15 non-reviewed publications, 4 reviews and 33 abstracts (total 82 publications) which were or are scheduled to be published as a result of this project. A listing of these publications grouped by area (i.e. amino acid metabolism, protein metabolism, carbohydrate metabolism, and space flight studies) are included.

Covalently functionalized graphene sheets with biocompatible natural amino acids

International Nuclear Information System (INIS)

Mallakpour, Shadpour; Abdolmaleki, Amir; Borandeh, Sedigheh

2014-01-01

Graphene sheets were covalently functionalized with aromatic–aliphatic amino acids (phenylalanine and tyrosine) and aliphatic amino acids (alanine, isoleucine, leucine, methionine and valine) by simple and green procedure. For this aim, at first natural graphite was converted into graphene oxide (GO) through strong oxidation procedure; then, based on the surface-exposed epoxy and carboxylic acid groups in GO solid, its surface modification with naturally occurring amino acids, occurred easily throughout the corresponding nucleophilic substitution and condensation reactions. Amino acid functionalized graphene demonstrates stable dispersion in water and common organic solvents. Fourier transform infrared, Raman and X-ray photoelectron spectroscopies, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy were used to investigate the nanostructures and properties of prepared materials. Each amino acid has different considerable effects on the structure and morphology of the pure graphite, from increasing the layer spacing to layer scrolling, based on their structures, functional groups and chain length. In addition, therogravimetric analysis was used for demonstrating a successful grafting of amino acid molecules to the surface of graphene.

An Examination of the Carbon Isotope Effects Associated with Amino Acid Biosynthesis

Science.gov (United States)

Scott, James H.; O'Brien, Diane M.; Emerson, David; Sun, Henry; McDonald, Gene D.; Salgado, Antonio; Fogel, Marilyn L.

2006-12-01

Stable carbon isotope ratios (δ13C) were determined for alanine, proline, phenylalanine, valine, leucine, isoleucine, aspartate (aspartic acid and asparagine), glutamate (glutamic acid and glutamine), lysine, serine, glycine, and threonine from metabolically diverse microorganisms. The microorganisms examined included fermenting bacteria, organotrophic, chemolithotrophic, phototrophic, methylotrophic, methanogenic, acetogenic, acetotrophic, and naturally occurring cryptoendolithic communities from the Dry Valleys of Antarctica. Here we demonstrated that reactions involved in amino acid biosynthesis can be used to distinguish amino acids formed by life from those formed by nonbiological processes. The unique patterns of δ13C imprinted by life on amino acids produced a biological bias. We also showed that, by applying discriminant function analysis to the δ13C value of a pool of amino acids formed by biological activity, it was possible to identify key aspects of intermediary carbon metabolism in the microbial world. In fact, microorganisms examined in this study could be placed within one of three metabolic groups: (1) heterotrophs that grow by oxidizing compounds containing three or more carbon-to-carbon bonds (fermenters and organotrophs), (2) autotrophs that grow by taking up carbon dioxide (chemolitotrophs and phototrophs), and (3) acetoclastic microbes that grow by assimilation of formaldehyde or acetate (methylotrophs, methanogens, acetogens, and acetotrophs). Furthermore, we demonstrated that cryptoendolithic communities from Antarctica grouped most closely with the autotrophs, which indicates that the dominant metabolic pathways in these communities are likely those utilized for CO2 fixation. We propose that this technique can be used to determine the dominant metabolic types in a community and reveal the overall flow of carbon in a complex ecosystem.

Amino acid profiling in the gestational diabetes mellitus

OpenAIRE

Rahimi, Najmeh; Razi, Farideh; Nasli-Esfahani, Ensieh; Qorbani, Mostafa; Shirzad, Nooshin; Larijani, Bagher

2017-01-01

Background The prevalence of gestational diabetes mellitus (GDM) is increasing globally which is associated with various side effects for mothers and fetus. It seems that metabolomic profiling of the amino acids may be useful in early diagnosis of metabolic diseases. This study aimed to explore the association of the amino acids profiles with GDM. Methods Eighty three pregnant women with gestational age ?25?weeks were randomly selected among pregnant women referred to prenatal care clinic in ...

Effects of amino acids on the physiochemical properties of potato starch.

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Cui, Min; Fang, Ling; Zhou, Hongxian; Yang, Hong

2014-05-15

The objective of this study was to evaluate effects of different amino acid additives (phenylalanine (Phe), methionine (Met), lysine (Lys), arginine (Arg), aspartic acid (Asp) and glutamic acid (Glu)) on the physicochemical properties of potato starch gels. Charge-carrying amino acids (Lys, Arg, Asp and Glu) significantly decreased the swelling power, solubility, light transmittance, L(∗) value and gel strength of potato starch, but increased syneresis during freeze-thaw treatment, while neutral amino acids (Phe and Met) did not cause modifications in starch gels. During heating, potato starch with fortified charge-carrying amino acids showed a lower peak G' (storage modulus), when compared with Phe and Met. Results showed that charge-carrying amino acids could modify physicochemical properties and improve the nutritional values of starch-based products. Copyright © 2013 Elsevier Ltd. All rights reserved.

Serum aminotransferases in nonalcoholic fatty liver disease are a signature of liver metabolic perturbations at the amino acid and Krebs cycle level.

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Sookoian, Silvia; Castaño, Gustavo O; Scian, Romina; Fernández Gianotti, Tomas; Dopazo, Hernán; Rohr, Cristian; Gaj, Graciela; San Martino, Julio; Sevic, Ina; Flichman, Diego; Pirola, Carlos J

2016-02-01

Extensive epidemiologic studies have shown that cardiovascular disease and the metabolic syndrome (MetS) are associated with serum concentrations of liver enzymes; however, fundamental characteristics of this relation are currently unknown. We aimed to explore the role of liver aminotransferases in nonalcoholic fatty liver disease (NAFLD) and MetS. Liver gene- and protein-expression changes of aminotransferases, including their corresponding isoforms, were evaluated in a case-control study of patients with NAFLD (n = 42), which was proven through a biopsy (control subjects: n = 10). We also carried out a serum targeted metabolite profiling to the glycolysis, gluconeogenesis, and Krebs cycle (n = 48) and an exploration by the next-generation sequencing of aminotransferase genes (n = 96). An in vitro study to provide a biological explanation of changes in the transcriptional level and enzymatic activity of aminotransferases was included. Fatty liver was associated with a deregulated liver expression of aminotransferases, which was unrelated to the disease severity. Metabolite profiling showed that serum aminotransferase concentrations are a signature of liver metabolic perturbations, particularly at the amino acid metabolism and Krebs cycle level. A significant and positive association between systolic hypertension and liver expression levels of glutamic-oxaloacetic transaminase 2 (GOT2) messenger RNA (Spearman R = 0.42, P = 0.03) was observed. The rs6993 located in the 3' untranslated region of the GOT2 locus was significantly associated with features of the MetS, including arterial hypertension [P = 0.028; OR: 2.285 (95% CI: 1.024, 5.09); adjusted by NAFLD severity] and plasma lipid concentrations. In the context of an abnormal hepatic triglyceride accumulation, circulating aminotransferases rise as a consequence of the need for increased reactions of transamination to cope with the liver metabolic derangement that is associated with greater gluconeogenesis and

Two food-borne heterocyclic amines: Metabolism and DNA adduct formation of amino-alpha-carbolines

DEFF Research Database (Denmark)

Frederiksen, Hanne

2005-01-01

or proteins of animal or vegetable origin, furthermore they are found in many cooked foods, such as fish, meat, and chicken. The specific mutagenicity of the amino-a-carbolines are lower in the Ames Salmonella assay than other heterocyclic amines, but in rodent studies the carcinogenicity of the aminoa, alpha......The amino-alpha-carbolines 2-amino-9H-pyrido[2,3-b]indole (A alpha C) and 2-amino-3-methyl-9H-pyrido-[2,3-b]indole (MeA alpha C) are two mutagenic and carcinogenic heterocyclic amines formed during ordinary cooking. Amino-alpha-carbolines can be formed in model systems by pyrolyzing tryptophan...

Interactive effects of seawater acidification and elevated temperature on biomineralization and amino acid metabolism in the mussel Mytilus edulis.

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Li, Shiguo; Liu, Chuang; Huang, Jingliang; Liu, Yangjia; Zheng, Guilan; Xie, Liping; Zhang, Rongqing

2015-11-01

Seawater acidification and warming resulting from anthropogenic production of carbon dioxide are increasing threats to marine ecosystems. Previous studies have documented the effects of either seawater acidification or warming on marine calcifiers; however, the combined effects of these stressors are poorly understood. In our study, we examined the interactive effects of elevated carbon dioxide partial pressure (P(CO2)) and temperature on biomineralization and amino acid content in an ecologically and economically important mussel, Mytilus edulis. Adult M. edulis were reared at different combinations of P(CO2) (pH 8.1 and 7.8) and temperature (19, 22 and 25°C) for 2 months. The results indicated that elevated P(CO2) significantly decreased the net calcification rate, the calcium content and the Ca/Mg ratio of the shells, induced the differential expression of biomineralization-related genes, modified shell ultrastructure and altered amino acid content, implying significant effects of seawater acidification on biomineralization and amino acid metabolism. Notably, elevated temperature enhanced the effects of seawater acidification on these parameters. The shell breaking force significantly decreased under elevated P(CO2), but the effect was not exacerbated by elevated temperature. The results suggest that the interactive effects of seawater acidification and elevated temperature on mussels are likely to have ecological and functional implications. This study is therefore helpful for better understanding the underlying effects of changing marine environments on mussels and other marine calcifiers. © 2015. Published by The Company of Biologists Ltd.

Metabolic strategies of beer spoilage lactic acid bacteria in beer.

Science.gov (United States)

Geissler, Andreas J; Behr, Jürgen; von Kamp, Kristina; Vogel, Rudi F

2016-01-04

Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis.

Metabolic Availability of the Limiting Amino Acids Lysine and Tryptophan in Cooked White African Cornmeal Assessed in Healthy Young Men Using the Indicator Amino Acid Oxidation Technique.

Science.gov (United States)

Rafii, Mahroukh; Elango, Rajavel; Ball, Ronald O; Pencharz, Paul B; Courtney-Martin, Glenda

2018-06-01

Maize is a staple food in many regions of the world, particularly in Africa and Latin America. However, maize protein is limiting in the indispensable amino acids lysine and tryptophan, making its protein of poor quality. The main objective of this study was to determine the protein quality of white African cornmeal by determining the metabolic availability (MA) of lysine and tryptophan. To determine the MA of lysine, 4 amounts of l-lysine (10, 13, 16, and 18 mg · kg-1 · d-1 totaling 28.6%, 37.1%, 45.7%, and 51.4% of the mean lysine requirement of 35 mg · kg-1 · d-1, respectively) were studied in 6 healthy young men in a repeated-measures design. To determine the MA of tryptophan, 4 amounts of l-tryptophan (0.5, 1, 1.5, and 2 mg · kg-1 · d-1 totaling 12.5%, 25.0%, 37.5%, and 50.0% of the mean tryptophan requirement of 4 mg · kg-1 · d-1, respectively) were studied in 7 healthy young men in a repeated-measures design. The MAs of lysine and tryptophan were estimated by comparing the indicator amino acid oxidation (IAAO) response with varying intakes of lysine and tryptophan in cooked white cornmeal compared with the IAAO response to l-lysine and l-tryptophan intakes in the reference protein (crystalline amino acid mixture patterned after egg protein) with the use of the slope ratio method. The MAs of lysine and tryptophan from African cooked white cornmeal were 71% and 80%, respectively. Our study provides a robust estimate of the availability of lysine and tryptophan in African white maize to healthy young men. This estimate provides a basis for postproduction fortification or supplementation of maize-based diets. This trial was registered at www.clinicaltrials.gov as NCT02402179.

O-Linked β-N-acetylglucosamine (O-GlcNAc) modification: a new pathway to decode pathogenesis of diabetic retinopathy.

Science.gov (United States)

Gurel, Zafer; Sheibani, Nader

2018-01-31

The incidence of diabetes continues to rise among all ages and ethnic groups worldwide. Diabetic retinopathy (DR) is a complication of diabetes that affects the retinal neurovasculature causing serious vision problems, including blindness. Its pathogenesis and severity is directly linked to the chronic exposure to high glucose conditions. No treatments are currently available to stop the development and progression of DR. To develop new and effective therapeutic approaches, it is critical to better understand how hyperglycemia contributes to the pathogenesis of DR at the cellular and molecular levels. We propose alterations in O-GlcNAc modification of target proteins during diabetes contribute to the development and progression of DR. The O-GlcNAc modification is regulated through hexosamine biosynthetic pathway. We showed this pathway is differentially activated in various retinal vascular cells under high glucose conditions perhaps due to their selective metabolic activity. O-GlcNAc modification can alter protein stability, activity, interactions, and localization. By targeting the same amino acid residues (serine and threonine) as phosphorylation, O-GlcNAc modification can either compete or cooperate with phosphorylation. Here we will summarize the effects of hyperglycemia-induced O-GlcNAc modification on the retinal neurovasculature in a cell-specific manner, providing new insight into the role of O-GlcNAc modification in early loss of retinal pericytes and the pathogenesis of DR. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The Role of Amino Acid Permeases and Tryptophan Biosynthesis in Cryptococcus neoformans Survival.

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João Daniel Santos Fernandes

Full Text Available Metabolic diversity is an important factor during microbial adaptation to different environments. Among metabolic processes, amino acid biosynthesis has been demonstrated to be relevant for survival for many microbial pathogens, whereas the association between pathogenesis and amino acid uptake and recycling are less well-established. Cryptococcus neoformans is an opportunistic fungal pathogen with many habitats. As a result, it faces frequent metabolic shifts and challenges during its life cycle. Here we studied the C. neoformans tryptophan biosynthetic pathway and found that the pathway is essential. RNAi indicated that interruptions in the biosynthetic pathway render strains inviable. However, auxotroph complementation can be partially achieved by tryptophan uptake when a non preferred nitrogen source and lower growth temperature are applied, suggesting that amino acid permeases may be the target of nitrogen catabolism repression (NCR. We used bioinformatics to search for amino acid permeases in the C. neoformans and found eight potential global permeases (AAP1 to AAP8. The transcriptional profile of them revealed that they are subjected to regulatory mechanisms which are known to respond to nutritional status in other fungi, such as (i quality of nitrogen (Nitrogen Catabolism Repression, NCR and carbon sources (Carbon Catabolism Repression, CCR, (ii amino acid availability in the extracellular environment (SPS-sensing and (iii nutritional deprivation (Global Amino Acid Control, GAAC. This study shows that C. neoformans has fewer amino acid permeases than other model yeasts, and that these proteins may be subjected to complex regulatory mechanisms. Our data suggest that the C. neoformans tryptophan biosynthetic pathway is an excellent pharmacological target. Furthermore, inhibitors of this pathway cause Cryptococcus growth arrest in vitro.

Overcoming the Refractory Expression of Secreted Recombinant Proteins in Mammalian Cells through Modification of the Signal Peptide and Adjacent Amino Acids.

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Güler-Gane, Gülin; Kidd, Sara; Sridharan, Sudharsan; Vaughan, Tristan J; Wilkinson, Trevor C I; Tigue, Natalie J

2016-01-01

The expression and subsequent purification of mammalian recombinant proteins is of critical importance to many areas of biological science. To maintain the appropriate tertiary structure and post-translational modifications of such proteins, transient mammalian expression systems are often adopted. The successful utilisation of these systems is, however, not always forthcoming and some recombinant proteins prove refractory to expression in mammalian hosts. In this study we focussed on the role of different N-terminal signal peptides and residues immediately downstream, in influencing the level of secreted recombinant protein obtained from suspension HEK293 cells. Using secreted alkaline phosphatase (SEAP) as a model protein, we identified that the +1/+2 downstream residues flanking a heterologous signal peptide significantly affect secreted levels. By incorporating these findings we conducted a comparison of different signal peptide sequences and identified the most productive as secrecon, a computationally-designed sequence. Importantly, in the context of the secrecon signal peptide and SEAP, we also demonstrated a clear preference for specific amino acid residues at the +1 position (e.g. alanine), and a detrimental effect of others (cysteine, proline, tyrosine and glutamine). When proteins that naturally contain these "undesirable" residues at the +1 position were expressed with their native signal peptide, the heterologous secrecon signal peptide, or secrecon with an additional alanine at the +1 or +1 and +2 position, the level of expression differed significantly and in an unpredictable manner. For each protein, however, at least one of the panel of signal peptide/adjacent amino acid combinations enabled successful recombinant expression. In this study, we highlight the important interplay between a signal peptide and its adjacent amino acids in enabling protein expression, and we describe a strategy that could enable recombinant proteins that have so far

tRNA's wobble decoding of the genome: 40 years of modification.

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Agris, Paul F; Vendeix, Franck A P; Graham, William D

2007-02-09

The genetic code is degenerate, in that 20 amino acids are encoded by 61 triplet codes. In 1966, Francis Crick hypothesized that the cell's limited number of tRNAs decoded the genome by recognizing more than one codon. The ambiguity of that recognition resided in the third base-pair, giving rise to the Wobble Hypothesis. Post-transcriptional modifications at tRNA's wobble position 34, especially modifications of uridine 34, enable wobble to occur. The Modified Wobble Hypothesis proposed in 1991 that specific modifications of a tRNA wobble nucleoside shape the anticodon architecture in such a manner that interactions were restricted to the complementary base plus a single wobble pairing for amino acids with twofold degenerate codons. However, chemically different modifications at position 34 would expand the ability of a tRNA to read three or even four of the fourfold degenerate codons. One foundation of Crick's Wobble Hypothesis was that a near-constant geometry of canonical base-pairing be maintained in forming all three base-pairs between the tRNA anticodon and mRNA codon on the ribosome. In accepting an aminoacyl-tRNA, the ribosome requires maintenance of a specific geometry for the anticodon-codon base-pairing. However, it is the post-transcriptional modifications at tRNA wobble position 34 and purine 37, 3'-adjacent to the anticodon, that pre-structure the anticodon domain to ensure the correct codon binding. The modifications create both the architecture and the stability needed for decoding through restraints on anticodon stereochemistry and conformational space, and through selective hydrogen bonding. A physicochemical understanding of modified nucleoside contributions to the tRNA anticodon domain architecture and its decoding of the genome has advanced RNA world evolutionary theory, the principles of RNA chemistry, and the application of this knowledge to the introduction of new amino acids to proteins.

Comparative Studies on Dyeability with Direct, Acid and Reactive Dyes after Chemical Modification of Jute with Mixed Amino Acids Obtained from Extract of Waste Soya Bean Seeds

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Bhaumik, Nilendu Sekhar; Konar, Adwaita; Roy, Alok Nath; Samanta, Ashis Kumar

2017-12-01

Jute fabric was treated with mixed natural amino acids obtained from waste soya bean seed extract for chemical modification of jute for its cataionization and to enhance its dyeability with anionic dyes (like direct, reactive and acid dye) as well enabling soya modified jute for salt free dyeing with anionic reactive dyes maintaining its eco-friendliness. Colour interaction parameters including surface colour strength were assessed and compared for both bleached and soya-modified jute fabric for reactive dyeing and compared with direct and acid dye. Improvement in K/S value (surface colour strength) was observed for soya-modified jute even in absence of salt applied in dye bath for reactive dyes as well as for direct and acid dyes. In addition, reactive dye also shows good dyeability even in acid bath in salt free conditions. Colour fastness to wash was evaluated for bleached and soya-modified jute fabric after dyeing with direct, acid and reactive dyes are reported. Treatment of jute with soya-extracted mixed natural amino acids showed anchoring of some amino/aldemine groups on jute cellulosic polymer evidenced from Fourier Transform Infra-Red (FTIR) Spectroscopy. This amino or aldemine group incorporation in bleached jute causes its cationization and hence when dyed in acid bath for reactive dye (instead of conventional alkali bath) showed dye uptake for reactive dyes. Study of surface morphology by Scanning Electron Microscopy (SEM) of said soya-modified jute as compared to bleached jute was studied and reported.

Acute effects of sodium valproate and gamma-vinyl GABA on regional amino acid metabolism in the rat brain: incorporation of 2-[14C]glucose into amino acids.

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Chapman, A G; Riley, K; Evans, M C; Meldrum, B S

1982-09-01

Amino acid concentrations have been determined in rat brain regions (cortex, striatum, cerebellum, and hippocampus) by HPLC after administration of acute anticonvulsant doses of sodium valproate (400 mg/kg, i.p.) and gamma-vinyl-GABA (1 g/kg, i.p.). After valproate administration the GABA level increases only in the cortex; aspartic acid concentration decreases in the cortex and hippocampus, and glutamic acid decreases in the hippocampus and striatum and increases in the cortex and cerebellum. There are no changes in the concentrations of glutamine, taurine, glycine, serine, and alanine following valproate administration. Only the GABA level increases in all the regions after gamma-vinyl-GABA administration. Cortical analyses 2, 4 and 10 minutes after pulse labeling with 2-[14C]glucose, i.v., show no change in the rate of cortical glucose utilization in the valproate treated group. The rate of labeling of glutamic acid is also unchanged, but the rate of labeling of GABA is reduced following valproate administration. After gamma-vinyl-GABA administration there is no change in the rate of labeling of GABA. These biochemical findings can be interpreted in terms of a primary anticonvulsant action of valproate on membrane receptors with secondary effects on the metabolism of amino acid neurotransmitters. This contrasts with the primary action of gamma-vinyl-GABA on GABA-transaminase activity.

Transcriptomic Changes in Response to Putrescine Production in Metabolically Engineered Corynebacterium glutamicum

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Zhen Li

2017-10-01

Full Text Available Putrescine is widely used in industrial production of bioplastics, pharmaceuticals, agrochemicals, and surfactants. Although engineered Corynebacterium glutamicum has been successfully used to produce high levels of putrescine, the overall cellular physiological and metabolic changes caused by overproduction of putrescine remains unclear. To reveal the transcriptional changes that occur in response to putrescine production in an engineered C. glutamicum strain, a comparative transcriptomic analysis was carried out. Overproduction of putrescine resulted in transcriptional downregulation of genes involved in glycolysis; the TCA cycle, pyruvate degradation, biosynthesis of some amino acids, oxidative phosphorylation; vitamin biosynthesis (thiamine and vitamin 6, metabolism of purine, pyrimidine and sulfur, and ATP-, NAD-, and NADPH-consuming enzymes. The transcriptional levels of genes involved in ornithine biosynthesis and NADPH-forming related enzymes were significantly upregulated in the putrescine producing C. glutamicum strain PUT-ALE. Comparative transcriptomic analysis provided some genetic modification strategies to further improve putrescine production. Repressing ATP- and NADPH-consuming enzyme coding gene expression via CRISPRi enhanced putrescine production.

Transcriptomic Changes in Response to Putrescine Production in Metabolically Engineered Corynebacterium glutamicum

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Li, Zhen; Liu, Jian-Zhong

2017-01-01

Putrescine is widely used in industrial production of bioplastics, pharmaceuticals, agrochemicals, and surfactants. Although engineered Corynebacterium glutamicum has been successfully used to produce high levels of putrescine, the overall cellular physiological and metabolic changes caused by overproduction of putrescine remains unclear. To reveal the transcriptional changes that occur in response to putrescine production in an engineered C. glutamicum strain, a comparative transcriptomic analysis was carried out. Overproduction of putrescine resulted in transcriptional downregulation of genes involved in glycolysis; the TCA cycle, pyruvate degradation, biosynthesis of some amino acids, oxidative phosphorylation; vitamin biosynthesis (thiamine and vitamin 6), metabolism of purine, pyrimidine and sulfur, and ATP-, NAD-, and NADPH-consuming enzymes. The transcriptional levels of genes involved in ornithine biosynthesis and NADPH-forming related enzymes were significantly upregulated in the putrescine producing C. glutamicum strain PUT-ALE. Comparative transcriptomic analysis provided some genetic modification strategies to further improve putrescine production. Repressing ATP- and NADPH-consuming enzyme coding gene expression via CRISPRi enhanced putrescine production. PMID:29089930

Variations of L- and D-amino acid levels in the brain of wild-type and mutant mice lacking D-amino acid oxidase activity.

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Du, Siqi; Wang, Yadi; Weatherly, Choyce A; Holden, Kylie; Armstrong, Daniel W

2018-05-01

D-amino acids are now recognized to be widely present in organisms and play essential roles in biological processes. Some D-amino acids are metabolized by D-amino acid oxidase (DAO), while D-Asp and D-Glu are metabolized by D-aspartate oxidase (DDO). In this study, levels of 22 amino acids and the enantiomeric compositions of the 19 chiral proteogenic entities have been determined in the whole brain of wild-type ddY mice (ddY/DAO +/+ ), mutant mice lacking DAO activity (ddY/DAO -/- ), and the heterozygous mice (ddY/DAO +/- ) using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). No significant differences were observed for L-amino acid levels among the three strains except for L-Trp which was markedly elevated in the DAO +/- and DAO -/- mice. The question arises as to whether this is an unknown effect of DAO inactivity. The three highest levels of L-amino acids were L-Glu, L-Asp, and L-Gln in all the three strains. The lowest L-amino acid level was L-Cys in ddY/DAO +/- and ddY/DAO -/- mice, while L-Trp showed the lowest level in ddY/DAO +/+ mice. The highest concentration of D-amino acid was found to be D-Ser, which also had the highest % D value (~ 25%). D-Glu had the lowest % D value (~ 0.01%) in all the three strains. Significant differences of D-Leu, D-Ala, D-Ser, D-Arg, and D-Ile were observed in ddY/DAO +/- and ddY/DAO -/- mice compared to ddY/DAO +/+ mice. This work provides the most complete baseline analysis of L- and D-amino acids in the brains of ddY/DAO +/+ , ddY/DAO +/- , and ddY/DAO -/- mice yet reported. It also provides the most effective and efficient analytical approach for measuring these analytes in biological samples. This study provides fundamental information on the role of DAO in the brain and may be relevant for future development involving novel drugs for DAO regulation.

Metabolic profiling of a mapping population exposes new insights in the regulation of seed metabolism and seed, fruit, and plant relations.

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David Toubiana

Full Text Available To investigate the regulation of seed metabolism and to estimate the degree of metabolic natural variability, metabolite profiling and network analysis were applied to a collection of 76 different homozygous tomato introgression lines (ILs grown in the field in two consecutive harvest seasons. Factorial ANOVA confirmed the presence of 30 metabolite quantitative trait loci (mQTL. Amino acid contents displayed a high degree of variability across the population, with similar patterns across the two seasons, while sugars exhibited significant seasonal fluctuations. Upon integration of data for tomato pericarp metabolite profiling, factorial ANOVA identified the main factor for metabolic polymorphism to be the genotypic background rather than the environment or the tissue. Analysis of the coefficient of variance indicated greater phenotypic plasticity in the ILs than in the M82 tomato cultivar. Broad-sense estimate of heritability suggested that the mode of inheritance of metabolite traits in the seed differed from that in the fruit. Correlation-based metabolic network analysis comparing metabolite data for the seed with that for the pericarp showed that the seed network displayed tighter interdependence of metabolic processes than the fruit. Amino acids in the seed metabolic network were shown to play a central hub-like role in the topology of the network, maintaining high interactions with other metabolite categories, i.e., sugars and organic acids. Network analysis identified six exceptionally highly co-regulated amino acids, Gly, Ser, Thr, Ile, Val, and Pro. The strong interdependence of this group was confirmed by the mQTL mapping. Taken together these results (i reflect the extensive redundancy of the regulation underlying seed metabolism, (ii demonstrate the tight co-ordination of seed metabolism with respect to fruit metabolism, and (iii emphasize the centrality of the amino acid module in the seed metabolic network. Finally, the study

N-terminal modifications of cellular proteins: The enzymes involved, their substrate specificities and biological effects

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Varland, Sylvia; Osberg, Camilla; Arnesen, Thomas

2015-01-01

The vast majority of eukaryotic proteins are N-terminally modified by one or more processing enzymes. Enzymes acting on the very first amino acid of a polypeptide include different peptidases, transferases, and ligases. Methionine aminopeptidases excise the initiator methionine leaving the nascent polypeptide with a newly exposed amino acid that may be further modified. N-terminal acetyl-, methyl-, myristoyl-, and palmitoyltransferases may attach an acetyl, methyl, myristoyl, or palmitoyl group, respectively, to the α-amino group of the target protein N-terminus. With the action of ubiquitin ligases, one or several ubiquitin molecules are transferred, and hence, constitute the N-terminal modification. Modifications at protein N-termini represent an important contribution to proteomic diversity and complexity, and are essential for protein regulation and cellular signaling. Consequently, dysregulation of the N-terminal modifying enzymes is implicated in human diseases. We here review the different protein N-terminal modifications occurring co- or post-translationally with emphasis on the responsible enzymes and their substrate specificities. PMID:25914051

Optical Sensors for Detection of Amino Acids.

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Pettiwala, Aafrin M; Singh, Prabhat K

2017-11-06

Amino acids are crucially involved in a myriad of biological processes. Any aberrant changes in physiological level of amino acids often manifest in common metabolic disorders, serious neurological conditions and cardiovascular diseases. Thus, devising methods for detection of trace amounts of amino acids becomes highly elemental to their efficient clinical diagnosis. Recently, the domain of developing optical sensors for detection of amino acids has witnessed significant activity which is the focus of the current review article. We undertook a detailed search of the peer-reviewed literature that primarily deals with optical sensors for amino acids and focuses on the use of different type of materials as a sensing platform. Ninety-five papers have been included in the review, majority of which deals with optical sensors. We attempt to systematically classify these contributions based on applications of various chemical and biological scaffolds such as polymers, supramolecular assemblies, nanoparticles, DNA, heparin etc. for the sensing of amino acids. This review identifies that supramolecular assemblies and nanomaterial continue to be commonly used materials to devise sensors for amino acids followed by surfactant assemblies. The broad implications of amino acids in human health and diagnosis have stirred a lot of interest to develop optimized optical detection systems for amino acids in recent years, using different materials based on chemical and biological scaffolds. We have also attempted to highlight the merits and demerits of some of the noteworthy sensor systems to instigate further efforts for constructing amino acids sensor based on unconventional concepts. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Amino acid metabolism and whole-body protein turnover in lambs ...

African Journals Online (AJOL)

The effect of protein supplementation of a wheat straw diet on the metabolism of lysine, leucine, methionine and urea, and on whole-body protein turnover rate was investigated in lambs. The metabolism of lysine and leucine is reported elsewhere (Cronje et aI., 1992); in this paper methionine metabolism is discussed, and ...

Akt-dependent Activation of the Heart 6-Phosphofructo-2-kinase/Fructose-2,6-bisphosphatase (PFKFB2) Isoenzyme by Amino Acids*

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Novellasdemunt, Laura; Tato, Irantzu; Navarro-Sabate, Aurea; Ruiz-Meana, Marisol; Méndez-Lucas, Andrés; Perales, Jose Carlos; Garcia-Dorado, David; Ventura, Francesc; Bartrons, Ramon; Rosa, Jose Luis

2013-01-01

Reciprocal regulation of metabolism and signaling allows cells to modulate their activity in accordance with their metabolic resources. Thus, amino acids could activate signal transduction pathways that control cell metabolism. To test this hypothesis, we analyzed the effect of amino acids on fructose-2,6-bisphosphate (Fru-2,6-P2) metabolism. We demonstrate that amino acids increase Fru-2,6-P2 concentration in HeLa and in MCF7 human cells. In conjunction with this, 6-phosphofructo-2-kinase activity, glucose uptake, and lactate concentration were increased. These data correlate with the specific phosphorylation of heart 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase (PFKFB2) isoenzyme at Ser-483. This activation was mediated by the PI3K and p38 signaling pathways. Furthermore, Akt inactivation blocked PFKFB2 phosphorylation and Fru-2,6-P2 production, thereby suggesting that the above signaling pathways converge at Akt kinase. In accordance with these results, kinase assays showed that amino acid-activated Akt phosphorylated PFKFB2 at Ser-483 and that knockdown experiments confirmed that the increase in Fru-2,6-P2 concentration induced by amino acids was due to PFKFB2. In addition, similar effects on Fru-2,6-P2 metabolism were observed in freshly isolated rat cardiomyocytes treated with amino acids, which indicates that these effects are not restricted to human cancer cells. In these cardiomyocytes, the glucose consumption and the production of lactate and ATP suggest an increase of glycolytic flux. Taken together, these results demonstrate that amino acids stimulate Fru-2,6-P2 synthesis by Akt-dependent PFKFB2 phosphorylation and activation and show how signaling and metabolism are inextricably linked. PMID:23457334

Glucagon Couples Hepatic Amino Acid Catabolism to mTOR-Dependent Regulation of α-Cell Mass

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Mark J. Solloway

2015-07-01

Full Text Available Understanding the regulation of islet cell mass has important implications for the discovery of regenerative therapies for diabetes. The liver plays a central role in metabolism and the regulation of endocrine cell number, but liver-derived factors that regulate α-cell and β-cell mass remain unidentified. We propose a nutrient-sensing circuit between liver and pancreas in which glucagon-dependent control of hepatic amino acid metabolism regulates α-cell mass. We found that glucagon receptor inhibition reduced hepatic amino acid catabolism, increased serum amino acids, and induced α-cell proliferation in an mTOR-dependent manner. In addition, mTOR inhibition blocked amino-acid-dependent α-cell replication ex vivo and enabled conversion of α-cells into β-like cells in vivo. Serum amino acids and α-cell proliferation were increased in neonatal mice but fell throughout postnatal development in a glucagon-dependent manner. These data reveal that amino acids act as sensors of glucagon signaling and can function as growth factors that increase α-cell proliferation.

Amides are novel protein modifications formed by physiological sugars.

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Glomb, M A; Pfahler, C

2001-11-09

The Maillard reaction, or nonenzymatic browning, proceeds in vivo, and the resulting protein modifications (advanced glycation end products) have been associated with various pathologies. Despite intensive research only very few structures have been established in vivo. We report here for the first time N(6)-[2-[(5-amino-5-carboxypentyl)amino]-2-oxoethyl]lysine (GOLA) and N(6)-glycoloyllysine (GALA) as prototypes for novel amide protein modifications produced by reducing sugars. Their identity was confirmed by independent synthesis and coupled liquid chromatography/mass spectrometry. Model reactions with N(alpha)-t-butoxycarbonyl-lysine showed that glyoxal and glycolaldehyde are immediate precursors, and reaction pathways are directly linked to N(epsilon)-carboxymethyllysine via glyoxal-imine structures. GOLA, the amide cross-link, and 1,3-bis(5-amino-5-carboxypentyl)imidazolium salt (GOLD), the imidazolium cross-link, share a common intermediate. The ratio of GOLA to GOLD is greater when glyoxal levels are low at constant lysine concentrations. GOLA and GALA formation from the Amadori product of glucose and lysine depends directly upon oxidation. With the advanced glycation end product inhibitors aminoguanidine and pyridoxamine we were able to dissect oxidative fragmentation of the Amadori product as a second mechanism of GOLA formation exactly coinciding with N(epsilon)-carboxymethyllysine synthesis. In contrast, the formation of GALA appears to depend solely upon glyoxal-imines. After enzymatic hydrolysis GOLA was found at 66 pmol/mg of brunescent lens protein. This suggests amide protein modifications as important markers of pathophysiological processes.

Tub-Tag Labeling; Chemoenzymatic Incorporation of Unnatural Amino Acids.

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Helma, Jonas; Leonhardt, Heinrich; Hackenberger, Christian P R; Schumacher, Dominik

2018-01-01

Tub-tag labeling is a chemoenzymatic method that enables the site-specific labeling of proteins. Here, the natural enzyme tubulin tyrosine ligase incorporates noncanonical tyrosine derivatives to the terminal carboxylic acid of proteins containing a 14-amino acid recognition sequence called Tub-tag. The tyrosine derivative carries a unique chemical reporter allowing for a subsequent bioorthogonal modification of proteins with a great variety of probes. Here, we describe the Tub-tag protein modification protocol in detail and explain its utilization to generate labeled proteins for advanced applications in cell biology, imaging, and diagnostics.

Plasma amino acids and metabolic profiling of dairy cows in response to a bolus duodenal infusion of leucine.

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Sadri, Hassan; von Soosten, Dirk; Meyer, Ulrich; Kluess, Jeannette; Dänicke, Sven; Saremi, Behnam; Sauerwein, Helga

2017-01-01

Leucine (Leu), one of the three branch chain amino acids, acts as a signaling molecule in the regulation of overall amino acid (AA) and protein metabolism. Leucine is also considered to be a potent stimulus for the secretion of insulin from pancreatice β-cells. Our objective was to study the effects of a duodenal bolus infusion of Leu on insulin and glucagon secretion, on plasma AA concentrations, and to do a metabolomic profiling of dairy cows as compared to infusions with either glucose or saline. Six duodenum-fistulated Holstein cows were studied in a replicated 3 × 3 Latin square design with 3 periods of 7 days, in which the treatments were applied at the end of each period. The treatments were duodenal bolus infusions of Leu (DIL; 0.15 g/kg body weight), glucose (DIG; at Leu equimolar dosage) or saline (SAL). On the day of infusion, the treatments were duodenally infused after 5 h of fasting. Blood samples were collected at -15, 0, 10, 20, 30, 40, 50, 60, 75, 90, 120, 180, 210, 240 and 300 min relative to the start of infusion. Blood plasma was assayed for concentrations of insulin, glucagon, glucose and AA. The metabolome was also characterized in selected plasma samples (i.e. from 0, 50, and 120 min relative to the infusion). Body weight, feed intake, milk yield and milk composition were recorded throughout the experiment. The Leu infusion resulted in significant increases of Leu in plasma reaching 20 and 15-fold greater values than that in DIG and SAL, respectively. The elevation of plasma Leu concentrations after the infusion led to a significant decrease (Pcows were reduced (Pinsulin were not affected by Leu. In DIG, insulin and glucose concentrations peaked at 30-40 and 40-50 min after the infusion, respectively. Insulin concentrations were greater (Pcows were compared with the DIG and SAL cows at 50 and 120 min after the infusion. By using this analysis, several metabolites, mainly acylcarnitines, methionine sulfoxide and components from the

Effects of branched-chain amino acids supplementation on both plasma amino acids concentration and muscle energetics changes resulting from muscle damage: A randomized placebo controlled trial.

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Fouré, Alexandre; Nosaka, Kazunori; Gastaldi, Marguerite; Mattei, Jean-Pierre; Boudinet, Hélène; Guye, Maxime; Vilmen, Christophe; Le Fur, Yann; Bendahan, David; Gondin, Julien

2016-02-01

Branched-chain amino acids promote muscle-protein synthesis, reduce protein oxidation and have positive effects on mitochondrial biogenesis and reactive oxygen species scavenging. The purpose of the study was to determine the potential benefits of branched-chain amino acids supplementation on changes in force capacities, plasma amino acids concentration and muscle metabolic alterations after exercise-induced muscle damage. (31)P magnetic resonance spectroscopy and biochemical analyses were used to follow the changes after such damage. Twenty six young healthy men were randomly assigned to supplemented branched-chain amino acids or placebo group. Knee extensors maximal voluntary isometric force was assessed before and on four days following exercise-induced muscle damage. Concentrations in phosphocreatine [PCr], inorganic phosphate [Pi] and pH were measured during a standardized rest-exercise-recovery protocol before, two (D2) and four (D4) days after exercise-induced muscle damage. No significant difference between groups was found for changes in maximal voluntary isometric force (-24% at D2 and -21% at D4). Plasma alanine concentration significantly increased immediately after exercise-induced muscle damage (+25%) in both groups while concentrations in glycine, histidine, phenylalanine and tyrosine decreased. No difference between groups was found in the increased resting [Pi] (+42% at D2 and +34% at D4), decreased resting pH (-0.04 at D2 and -0.03 at D4) and the slower PCr recovery rate (-18% at D2 and -24% at D4). The damaged muscle was not able to get benefits out of the increased plasma branched-chain amino acids availability to attenuate changes in indirect markers of muscle damage and muscle metabolic alterations following exercise-induced muscle damage. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Sulfur amino acids are necessary for normal intestinal mucosal growth in neonatal piglets

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Sulfur amino acids (SAAs) methionine and cysteine play important metabolic and functional role in human health and disease. Gastrointestinal tract is an important site of transmethylation and transsulfuration of methionine and metabolizes approx. 20% of the dietary methionine intake (Riedijk et al. ...

Interactive network analysis of the plasma amino acids profile in a mouse model of hyperglycemia

OpenAIRE

Tanaka, Takayuki; Mochida, Taiga; Maki, Yukihiro; Shiraki, Yasuko; Mori, Hiroko; Matsumoto, Shirou; Shimbo, Kazutaka; Ando, Toshihiko; Nakamura, Kimitoshi; Endo, Fumio; Okamoto, Masahiro

2013-01-01

Amino acids are a group of metabolites that are important substrates for protein synthesis, are important as signaling molecules and play central roles as highly connected metabolic hubs, and therefore, there are many reports that describe disease-specific abnormalities in plasma amino acids profile. However, the causes of progression from a healthy control to a manifestation of the plasma amino acid changes remain obscure. Here, we extended the plasma amino acids profile to relationships tha...

New Functions and Potential Applications of Amino Acids.

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Uneyama, Hisayuki; Kobayashi, Hisamine; Tonouchi, Naoto

Currently, several types of amino acids are being produced and used worldwide. Nevertheless, several new functions of amino acids have been recently discovered that could result in other applications. For example, oral stimulation by glutamate triggers the cephalic phase response to prepare for food digestion. Further, the stomach and intestines have specific glutamate-recognizing systems in their epithelial mucosa. Regarding clinical applications, addition of monosodium glutamate to the medicinal diet has been shown to markedly enhance gastric secretion in a vagus-dependent manner. Branched-chain amino acids (BCAAs) are the major components of muscles, and ingestion of BCAAs has been found to be effective for decreasing muscle pain. BCAAs are expected to be a solution for the serious issue of aging. Further, ingestion of specific amino acids could be beneficial. Glycine can be ingested for good night's sleep: glycine ingestion before bedtime significantly improved subjective sleep quality. Ingestion of alanine and glutamine effectively accelerates alcohol metabolism, and ingestion of cystine and theanine effectively prevents colds. Finally, amino acids could be used in a novel clinical diagnostic method: the balance of amino acids in the blood could be an indicator of the risk of diseases such as cancer. These newly discovered functions of amino acids are expected to contribute to the resolution of various issues.

Amino acids in the cultivation of mammalian cells.

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Salazar, Andrew; Keusgen, Michael; von Hagen, Jörg

2016-05-01

Amino acids are crucial for the cultivation of mammalian cells. This importance of amino acids was realized soon after the development of the first cell lines, and a solution of a mixture of amino acids has been supplied to cultured cells ever since. The importance of amino acids is further pronounced in chemically defined mammalian cell culture media, making the consideration of their biological and chemical properties necessary. Amino acids concentrations have been traditionally adjusted to their cellular consumption rates. However, since changes in the metabolic equilibrium of amino acids can be caused by changes in extracellular concentrations, metabolomics in conjunction with flux balance analysis is being used in the development of culture media. The study of amino acid transporters is also gaining importance since they control the intracellular concentrations of these molecules and are influenced by conditions in cell culture media. A better understanding of the solubility, stability, dissolution kinetics, and interactions of these molecules is needed for an exploitation of these properties in the development of dry powdered chemically defined media for mammalian cells. Due to the complexity of these mixtures however, this has proven to be challenging. Studying amino acids in mammalian cell culture media will help provide a better understanding of how mammalian cells in culture interact with their environment. It would also provide insight into the chemical behavior of these molecules in solutions of complex mixtures, which is important in the understanding of the contribution of individual amino acids to protein structure.

Amino Acid Enantiomeric Ratios in Biogeochemistry: Complications and Opportunities

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McDonald, G. D.; Sun, H. J.; Tsapin, A. I.

2003-12-01

Amino acid enantiomeric ratios have been used for many years as an indicator of the process of racemization, and thus as a method to determine the age of biological samples such as bones, shells, and teeth. Dating biological samples by this method relies on an accurate knowledge of the environmental temperatures the sample has experienced, and the racemization kinetic parameters in the sample matrix. In some environments, where an independent dating method such as radiocarbon is available, the observed amino acid D/L ratios are found to be either higher or lower than those expected due to racemization alone. The observed D/L ratios in these cases can be clues to biogeochemical processes operating in addition to, or in place of, chemical racemization. In Siberian permafrost (Brinton et al. 2002, Astrobiology 2, 77) we have found D/L ratios lower than expected, which we have interpreted as evidence for low-level D-amino acid metabolism and recycling in microorganisms previously thought to be metabolically dormant. In microbially-colonized Antarctic Dry Valley sandstones (McDonald and Sun 2002, Eos Trans. AGU 83, Fall Meet. Suppl., Abstract B11A-0720) we have found D/L ratios higher than can be accounted for by racemization alone, most likely due to the accumulation of D-amino-acid-containing peptidoglycan material from multiple bacterial generations. D/L profiles in polar ices and in ice-covered lakes (Tsapin et al. 2002, Astrobiology 2, 632) can be used to indicate the sources and histories of water or ice samples. Multiple biological and biogeochemical processes may complicate the interpretation of amino acid enantiomeric excesses in both terrestrial and extraterrestrial samples; however, amino acid racemization remains a useful tool in biogeochemistry and astrobiology. With a good knowledge of the environmental history of samples, amino acid D/L profiles can be used as a window into processes such as molecular repair and biomass turnover that are difficult to

Incorporation of post-translational modified amino acids as an approach to increase both chemical and biological diversity of conotoxins and conopeptides.

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Espiritu, Michael J; Cabalteja, Chino C; Sugai, Christopher K; Bingham, Jon-Paul

2014-01-01

Bioactive peptides from Conus venom contain a natural abundance of post-translational modifications that affect their chemical diversity, structural stability, and neuroactive properties. These modifications have continually presented hurdles in their identification and characterization. Early endeavors in their analysis relied on classical biochemical techniques that have led to the progressive development and use of novel proteomic-based approaches. The critical importance of these post-translationally modified amino acids and their specific assignment cannot be understated, having impact on their folding, pharmacological selectivity, and potency. Such modifications at an amino acid level may also provide additional insight into the advancement of conopeptide drugs in the quest for precise pharmacological targeting. To achieve this end, a concerted effort between the classical and novel approaches is needed to completely elucidate the role of post-translational modifications in conopeptide structure and dynamics. This paper provides a reflection in the advancements observed in dealing with numerous and multiple post-translationally modified amino acids within conotoxins and conopeptides and provides a summary of the current techniques used in their identification.

Ammonia production from amino acid-based biomass-like sources by engineered Escherichia coli.

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Mikami, Yosuke; Yoneda, Hisanari; Tatsukami, Yohei; Aoki, Wataru; Ueda, Mitsuyoshi

2017-12-01

The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber-Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to promote ammonia production using the overexpression of the ketoisovalerate decarboxylase gene (kivd), derived from Lactococcus lactis, ammonia production from amino acids was 351 mg/L (36.6% yield). Furthermore, we deleted the glnA gene, responsible for ammonia assimilation. Using yeast extract as the sole source of carbon and nitrogen, the resultant strain produced 458 mg/L of ammonia (47.8% yield) from an amino acid-based biomass-like material. The ammonia production yields obtained are the highest reported to date. This study suggests that it will be possible to produce ammonia from waste biomass in an environmentally friendly process.

GlmS and NagB regulate amino sugar metabolism in opposing directions and affect Streptococcus mutans virulence.

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Miki Kawada-Matsuo

Full Text Available Streptococcus mutans is a cariogenic pathogen that produces an extracellular polysaccharide (glucan from dietary sugars, which allows it to establish a reproductive niche and secrete acids that degrade tooth enamel. While two enzymes (GlmS and NagB are known to be key factors affecting the entrance of amino sugars into glycolysis and cell wall synthesis in several other bacteria, their roles in S. mutans remain unclear. Therefore, we investigated the roles of GlmS and NagB in S. mutans sugar metabolism and determined whether they have an effect on virulence. NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc. A glmS-inactivated mutant could not grow in the absence of GlcNAc, while nagB-inactivated mutant growth was decreased in the presence of GlcNAc. Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation. Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively.

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains

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Samantha Fairbairn

2017-12-01

Full Text Available Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways.

Branched-chain amino acids in metabolic signaling and insulin resistance

Science.gov (United States)

Branched-chain amino acids (BCAAs) are important directly- and indirectly-acting nutrient signals. Frequently, their actions have been reported to be anti-obesity in nature, especially in rodent models. Yet, circulating BCAAs tend to be elevated in obesity, and even associated with poorer metaboli...

In search of druggable targets for GBM amino acid metabolism

NARCIS (Netherlands)

Panosyan, Eduard H.; Lin, Henry J.; Koster, Jan; Lasky, Joseph L.

2017-01-01

Background: Amino acid (AA) pathways may contain druggable targets for glioblastoma (GBM). Literature reviews and GBM database (http://r2.amc.nl) analyses were carried out to screen for such targets among 95 AA related enzymes. Methods: First, we identified the genes that were differentially

Upward translocation of 14C-amino compounds in xylem and phloem of citrus trees (citrus unshiu marc.)

International Nuclear Information System (INIS)

Kato, Tadashi; Yamagata, Makoto; Tsukahara, Sadao

1985-01-01

Upward and lateral movements of 14 C-amino compounds in intact trees and excised shoots, and upward translocation of major amino compounds in intact shoots were examined in the early stage of new shoot development. The results were summarized as follows. 1. Uniformly 14 C-labelled arginine, asparagine, aspartic acid and proline were steadily taken up by roots of intact trees, translocated to old leaves and new shoots, and appeared in the fed compound and its metabolized products in these organs. 2. 14 C-arginine, asparagine and proline were translocated upward not only via the xylem but also via the phloem. Lateral movements, from the xylem to the pholoem and from the phloem to the xylem, also occurred. These compounds showed different patterns in their movements. 14 C-arginine and its metabolic products tended to accumulate in the xylem and translocate upward in the xylem. This was in contrast to 14 C-proline and its metabolic products, which tended to accumulate in the phloem and translocate upward in the phloem. These findings were supported by the results obtained in intact shoots. 3. The 14 C-amino compounds were metabolized to soluble and insoluble compounds during the translocation and in the new shoots. However, they differed significantly in the extent of metabolic conversion during translocation; proline was hardly metabolized, arginine and asparagine were moderately metabolized, and aspartic acid was almost completely metabolized. (author)

Discovery of a novel amino acid racemase through exploration of natural variation in Arabidopsis thaliana

Science.gov (United States)

Strauch, Renee C.; Svedin, Elisabeth; Dilkes, Brian; Chapple, Clint; Li, Xu

2015-01-01

Plants produce diverse low-molecular-weight compounds via specialized metabolism. Discovery of the pathways underlying production of these metabolites is an important challenge for harnessing the huge chemical diversity and catalytic potential in the plant kingdom for human uses, but this effort is often encumbered by the necessity to initially identify compounds of interest or purify a catalyst involved in their synthesis. As an alternative approach, we have performed untargeted metabolite profiling and genome-wide association analysis on 440 natural accessions of Arabidopsis thaliana. This approach allowed us to establish genetic linkages between metabolites and genes. Investigation of one of the metabolite–gene associations led to the identification of N-malonyl-d-allo-isoleucine, and the discovery of a novel amino acid racemase involved in its biosynthesis. This finding provides, to our knowledge, the first functional characterization of a eukaryotic member of a large and widely conserved phenazine biosynthesis protein PhzF-like protein family. Unlike most of known eukaryotic amino acid racemases, the newly discovered enzyme does not require pyridoxal 5′-phosphate for its activity. This study thus identifies a new d-amino acid racemase gene family and advances our knowledge of plant d-amino acid metabolism that is currently largely unexplored. It also demonstrates that exploitation of natural metabolic variation by integrating metabolomics with genome-wide association is a powerful approach for functional genomics study of specialized metabolism. PMID:26324904

Protein covalent modification by biologically active quinones

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MIROSLAV J. GASIC

2004-11-01

Full Text Available The avarone/avarol quinone/hydroquinone couple shows considerable antitumor activity. In this work, covalent modification of b-lactoglobulin by avarone and its derivatives as well as by the synthetic steroidal quinone 2,5(10-estradiene-1,4,17-trione and its derivatives were studied. The techniques for studying chemical modification of b-lactoglobulin by quinones were: UV/Vis spectrophotometry, SDS PAGE and isoelectrofocusing. SDS PAGE results suggest that polymerization of the protein occurs. It could be seen that the protein of 18 kD gives the bands of 20 kD, 36 kD, 40 kD, 45 kD, 64 kD and 128 kD depending on modification agent. The shift of the pI of the protein (5.4 upon modification toward lower values (from pI 5.0 to 5.3 indicated that lysine amino groups are the principal site of the reaction of b-lactoglobulin with the quinones.

substantiation of the standards for tritium amino acids intake by human organism

International Nuclear Information System (INIS)

Zhesko, T.V.; Balonov, M.I.

1984-01-01

Calculated values of β-irradiation tissue doses of bound tritium and tritium oxide absorbed by animals treated with different amino acids are given. The obtained dose values are compared with tritium water doses. The data obtained in animal studies are extrapolated to man in order to determine the dose equivalent to the incorporated 3 H-amino acids dose. It is assumed that the dose equivalent to 3 H-amino acids radiation is three times as high as the equivalent amount of tritium oxide. 9 mCi/yr is established as the maximum allowable blood intake of 3 H-amino acids. Due to their metabolic characteristics, air permissible concentrations of 3 H-amino acids and tritium oxide have approximately the same values. The value of 30 nCi/cm 2 is recommended as a standard for work clothing contamination with 3 H-amino acids

Scaffolding along Nucleic Acid Duplexes Using 2'-Amino-Locked Nucleic Acids

DEFF Research Database (Denmark)

Astakhova, I Kira; Wengel, Jesper

2014-01-01

-LNA nucleotides. By application of different chemical reactions, modification of 2'-amino-LNA scaffolds can be efficiently performed in high yields and with various tags, postsynthetically or during the automated oligonucleotide synthesis. The choice of a synthetic method for scaffolding along 2'-amino-LNA mainly....../DNA probes bind nucleic acid targets with advantages of high affinity and specificity. Thus, molecular motion of nanodevices and programmable self-assembly of chemically modified LNA/DNA nanomaterials can be followed by bright fluorescence signaling from the functionalized LNA units. Another appealing aspect...

Enhanced amino acid utilization sustains growth of cells lacking Snf1/AMPK

DEFF Research Database (Denmark)

Nicastro, Raffaele; Tripodi, Farida; Guzzi, Cinzia

2015-01-01

when grown with glucose excess. We show that loss of Snf1 in cells growing in 2% glucose induces an extensive transcriptional reprogramming, enhances glycolytic activity, fatty acid accumulation and reliance on amino acid utilization for growth. Strikingly, we demonstrate that Snf1/AMPK-deficient cells...... remodel their metabolism fueling mitochondria and show glucose and amino acids addiction, a typical hallmark of cancer cells....

Prediction of protein modification sites of pyrrolidone carboxylic acid using mRMR feature selection and analysis.

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Lu-Lu Zheng

Full Text Available Pyrrolidone carboxylic acid (PCA is formed during a common post-translational modification (PTM of extracellular and multi-pass membrane proteins. In this study, we developed a new predictor to predict the modification sites of PCA based on maximum relevance minimum redundancy (mRMR and incremental feature selection (IFS. We incorporated 727 features that belonged to 7 kinds of protein properties to predict the modification sites, including sequence conservation, residual disorder, amino acid factor, secondary structure and solvent accessibility, gain/loss of amino acid during evolution, propensity of amino acid to be conserved at protein-protein interface and protein surface, and deviation of side chain carbon atom number. Among these 727 features, 244 features were selected by mRMR and IFS as the optimized features for the prediction, with which the prediction model achieved a maximum of MCC of 0.7812. Feature analysis showed that all feature types contributed to the modification process. Further site-specific feature analysis showed that the features derived from PCA's surrounding sites contributed more to the determination of PCA sites than other sites. The detailed feature analysis in this paper might provide important clues for understanding the mechanism of the PCA formation and guide relevant experimental validations.

Isotopomer distributions in amino acids from a highly expressed protein as a proxy for those from total protein

Energy Technology Data Exchange (ETDEWEB)

Shaikh, Afshan; Shaikh, Afshan S.; Tang, Yinjie; Mukhopadhyay, Aindrila; Keasling, Jay D.

2008-06-27

{sup 13}C-based metabolic flux analysis provides valuable information about bacterial physiology. Though many biological processes rely on the synergistic functions of microbial communities, study of individual organisms in a mixed culture using existing flux analysis methods is difficult. Isotopomer-based flux analysis typically relies on hydrolyzed amino acids from a homogeneous biomass. Thus metabolic flux analysis of a given organism in a mixed culture requires its separation from the mixed culture. Swift and efficient cell separation is difficult and a major hurdle for isotopomer-based flux analysis of mixed cultures. Here we demonstrate the use of a single highly-expressed protein to analyze the isotopomer distribution of amino acids from one organism. Using the model organism E. coli expressing a plasmid-borne, his-tagged Green Fluorescent Protein (GFP), we show that induction of GFP does not affect E. coli growth kinetics or the isotopomer distribution in nine key metabolites. Further, the isotopomer labeling patterns of amino acids derived from purified GFP and total cell protein are indistinguishable, indicating that amino acids from a purified protein can be used to infer metabolic fluxes of targeted organisms in a mixed culture. This study provides the foundation to extend isotopomer-based flux analysis to study metabolism of individual strains in microbial communities.

Single-Cell Biomolecular Analysis of Coral Algal Symbionts Reveals Opposing Metabolic Responses to Heat Stress and Expulsion

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Katherina Petrou

2018-03-01

Full Text Available The success of corals in nutrient poor environments is largely attributed to the symbiosis between the cnidarian host and its intracellular alga. Warm water anomalies have been shown to destabilize this symbiosis, yet detailed analysis of the effect of temperature and expulsion on cell-specific carbon and nutrient allocation in the symbiont is limited. Here, we exposed colonies of the hard coral Acropora millepora to heat stress and using synchrotron-based infrared microspectroscopy measured the biomolecular profiles of individual in hospite and expelled symbiont cells at an acute state of bleaching. Our results showed symbiont metabolic profiles to be remarkably distinct with heat stress and expulsion, where the two effectors elicited opposing metabolic adjustments independent of treatment or cell type. Elevated temperature resulted in biomolecular changes reflecting cellular stress, with relative increases in free amino acids and phosphorylation of molecules and a concomitant decline in protein content, suggesting protein modification and degradation. This contrasted with the metabolic profiles of expelled symbionts, which showed relative decreases in free amino acids and phosphorylated molecules, but increases in proteins and lipids, suggesting expulsion lessens the overall effect of heat stress on the metabolic signature of the algal symbionts. Interestingly, the combined effects of expulsion and thermal stress were additive, reducing the overall shifts in all biomolecules, with the notable exception of the significant accumulation of lipids and saturated fatty acids. This first use of a single-cell metabolomics approach on the coral symbiosis provides novel insight into coral bleaching and emphasizes the importance of a single-cell approach to demark the cell-to-cell variability in the physiology of coral cellular populations.

Amino acids as regulators and components of nonproteinogenic pathways

NARCIS (Netherlands)

Meijer, Alfred J.

2003-01-01

Amino acids are not only important precursors for the synthesis of proteins and other N-containing compounds, but also participate in the regulation of major metabolic pathways. Glutamate and aspartate, for example, are components of the malate/aspartate shuttle and their concentrations control the

Determination of Amino Acids in Medicinal Plants from Southern ...

African Journals Online (AJOL)

synthesis, cell metabolism, ammonia detoxification, antioxidant activity and alkaloid synthesis, suggesting that the ... protein phosphorylation, synthesis of hormones and antioxidant capacity [3]. Also, amino ... to several stress conditions such as high and low ..... traditional medicinal and food uses of four plants in. Oaxaca ...

A metabolic signature of long life in Caenorhabditis elegans

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Viney Jonathan M

2010-02-01

Full Text Available Abstract Background Many Caenorhabditis elegans mutations increase longevity and much evidence suggests that they do so at least partly via changes in metabolism. However, up until now there has been no systematic investigation of how the metabolic networks of long-lived mutants differ from those of normal worms. Metabolomic technologies, that permit the analysis of many untargeted metabolites in parallel, now make this possible. Here we use one of these, 1H nuclear magnetic resonance spectroscopy, to investigate what makes long-lived worms metabolically distinctive. Results We examined three classes of long-lived worms: dauer larvae, adult Insulin/IGF-1 signalling (IIS-defective mutants, and a translation-defective mutant. Surprisingly, these ostensibly different long-lived worms share a common metabolic signature, dominated by shifts in carbohydrate and amino acid metabolism. In addition the dauer larvae, uniquely, had elevated levels of modified amino acids (hydroxyproline and phosphoserine. We interrogated existing gene expression data in order to integrate functional (metabolite-level changes with transcriptional changes at a pathway level. Conclusions The observed metabolic responses could be explained to a large degree by upregulation of gluconeogenesis and the glyoxylate shunt as well as changes in amino acid catabolism. These responses point to new possible mechanisms of longevity assurance in worms. The metabolic changes observed in dauer larvae can be explained by the existence of high levels of autophagy leading to recycling of cellular components. See associated minireview: http://jbiol.com/content/9/1/7

Metabolic Diseases Downregulate the Majority of Histone Modification Enzymes, Making a Few Upregulated Enzymes Novel Therapeutic Targets--"Sand Out and Gold Stays".

Science.gov (United States)

Shao, Ying; Chernaya, Valeria; Johnson, Candice; Yang, William Y; Cueto, Ramon; Sha, Xiaojin; Zhang, Yi; Qin, Xuebin; Sun, Jianxin; Choi, Eric T; Wang, Hong; Yang, Xiao-feng

2016-02-01

To determine whether the expression of histone modification enzymes is regulated in physiological and pathological conditions, we took an experimental database mining approach pioneered in our labs to determine a panoramic expression profile of 164 enzymes in 19 human and 17 murine tissues. We have made the following significant findings: (1) Histone enzymes are differentially expressed in cardiovascular, immune, and other tissues; (2) our new pyramid model showed that heart and T cells are among a few tissues in which histone acetylation/deacetylation, and histone methylation/demethylation are in the highest varieties; and (3) histone enzymes are more downregulated than upregulated in metabolic diseases and regulatory T cell (Treg) polarization/ differentiation, but not in tumors. These results have demonstrated a new working model of "Sand out and Gold stays," where more downregulation than upregulation of histone enzymes in metabolic diseases makes a few upregulated enzymes the potential novel therapeutic targets in metabolic diseases and Treg activity.

Post hoc analysis of plasma amino acid profiles: towards a specific pattern in autism spectrum disorder and intellectual disability.

Science.gov (United States)

Delaye, Jean-Baptiste; Patin, Franck; Lagrue, Emmanuelle; Le Tilly, Olivier; Bruno, Clement; Vuillaume, Marie-Laure; Raynaud, Martine; Benz-De Bretagne, Isabelle; Laumonnier, Frederic; Vourc'h, Patrick; Andres, Christian; Blasco, Helene

2018-01-01

Objectives Autism spectrum disorders and intellectual disability present a challenge for therapeutic and dietary management. We performed a re-analysis of plasma amino acid chromatography of children with autism spectrum disorders ( n = 22) or intellectual disability ( n = 29) to search for a metabolic signature that can distinguish individuals with these disorders from controls ( n = 30). Methods We performed univariate and multivariate analyses using different machine learning strategies, from the raw data of the amino acid chromatography. Finally, we analysed the metabolic pathways associated with discriminant biomarkers. Results Multivariate analysis revealed models to discriminate patients with autism spectrum disorders or intellectual disability and controls from plasma amino acid profiles ( P intellectual disability patients shared similar differences relative to controls, including lower glutamate ( P intellectual disability revealed the involvement of urea, 3-methyl-histidine and histidine metabolism. Biosigner analysis and univariate analysis confirmed the role of 3-methylhistidine ( P = 0.004), histidine ( P = 0.003), urea ( P = 0.0006) and lysine ( P = 0.002). Conclusions We revealed discriminant metabolic patterns between autism spectrum disorders, intellectual disability and controls. Amino acids known to play a role in neurotransmission were discriminant in the models comparing autism spectrum disorders or intellectual disability to controls, and histidine and b-alanine metabolism was specifically highlighted in the model.

Identification of a novel amino acid racemase from a hyperthermophilic archaeon Pyrococcus horikoshii OT-3 induced by D-amino acids.

Science.gov (United States)

Kawakami, Ryushi; Ohmori, Taketo; Sakuraba, Haruhiko; Ohshima, Toshihisa

2015-08-01

To date, there have been few reports analyzing the amino acid requirement for growth of hyperthermophilic archaea. We here found that the hyperthermophilic archaeon Pyrococcus horikoshii OT-3 requires Thr, Leu, Val, Phe, Tyr, Trp, His and Arg in the medium for growth, and shows slow growth in medium lacking Met or Ile. This largely corresponds to the presence, or absence, of genes related to amino acid biosynthesis in its genome, though there are exceptions. The amino acid requirements were dramatically lost by addition of D-isomers of Met, Leu, Val, allo-Ile, Phe, Tyr, Trp and Arg. Tracer analysis using (14)C-labeled D-Trp showed that D-Trp in the medium was used as a protein component in the cells, suggesting the presence of D-amino acid metabolic enzymes. Pyridoxal 5'-phosphate (PLP)-dependent racemase activity toward Met, Leu and Phe was detected in crude extract of P. horikoshii and was enhanced in cells grown in the medium supplemented with D-amino acids, especially D-allo-Ile. The gene encoding the racemase was narrowed down to one open reading frame on the basis of enzyme purification from P. horikoshii cells, and the recombinant enzyme exhibited PLP-dependent racemase activity toward several amino acids, including Met, Leu and Phe, but not Pro, Asp or Glu. This is the first report showing the presence in a hyperthermophilic archaeon of a PLP-dependent amino acid racemase with broad substrate specificity that is likely responsible for utilization of D-amino acids for growth.

Synthesis and biological activity of amino acid conjugates of abscisic acid.

Science.gov (United States)

Todoroki, Yasushi; Narita, Kenta; Muramatsu, Taku; Shimomura, Hajime; Ohnishi, Toshiyuki; Mizutani, Masaharu; Ueno, Kotomi; Hirai, Nobuhiro

2011-03-01

We prepared 19 amino acid conjugates of the plant hormone abscisic acid (ABA) and investigated their biological activity, enzymatic hydrolysis by a recombinant Arabidopsis amidohydrolases GST-ILR1 and GST-IAR3, and metabolic fate in rice seedlings. Different sets of ABA-amino acids induced ABA-like responses in different plants. Some ABA-amino acids, including some that were active in bioassays, were hydrolyzed by recombinant Arabidopsis GST-IAR3, although GST-ILR1 did not show hydrolysis activity for any of the ABA-amino acids. ABA-L-Ala, which was active in all the bioassays, an Arabidopsis seed germination, spinach seed germination, and rice seedling elongation assays, except in a lettuce seed germination assay and was hydrolyzed by GST-IAR3, was hydrolyzed to free ABA in rice seedlings. These findings suggest that some plant amidohydrolases hydrolyze some ABA-amino acid conjugates. Because our study indicates the possibility that different plants have hydrolyzing activity toward different ABA-amino acids, an ABA-amino acid may function as a species-selective pro-hormone of ABA. Copyright © 2011 Elsevier Ltd. All rights reserved.

Endurance performance and energy metabolism during exercise in mice with a muscle-specific defect in the control of branched-chain amino acid catabolism.

Science.gov (United States)

Xu, Minjun; Kitaura, Yasuyuki; Ishikawa, Takuya; Kadota, Yoshihiro; Terai, Chihaya; Shindo, Daichi; Morioka, Takashi; Ota, Miki; Morishita, Yukako; Ishihara, Kengo; Shimomura, Yoshiharu

2017-01-01

It is known that the catabolism of branched-chain amino acids (BCAAs) in skeletal muscle is suppressed under normal and sedentary conditions but is promoted by exercise. BCAA catabolism in muscle tissues is regulated by the branched-chain α-keto acid (BCKA) dehydrogenase complex, which is inactivated by phosphorylation by BCKA dehydrogenase kinase (BDK). In the present study, we used muscle-specific BDK deficient mice (BDK-mKO mice) to examine the effect of uncontrolled BCAA catabolism on endurance exercise performance and skeletal muscle energy metabolism. Untrained control and BDK-mKO mice showed the same performance; however, the endurance performance enhanced by 2 weeks of running training was somewhat, but significantly less in BDK-mKO mice than in control mice. Skeletal muscle of BDK-mKO mice had low levels of glycogen. Metabolome analysis showed that BCAA catabolism was greatly enhanced in the muscle of BDK-mKO mice and produced branched-chain acyl-carnitine, which induced perturbation of energy metabolism in the muscle. These results suggest that the tight regulation of BCAA catabolism in muscles is important for homeostasis of muscle energy metabolism and, at least in part, for adaptation to exercise training.

Endurance performance and energy metabolism during exercise in mice with a muscle-specific defect in the control of branched-chain amino acid catabolism.

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Minjun Xu

Full Text Available It is known that the catabolism of branched-chain amino acids (BCAAs in skeletal muscle is suppressed under normal and sedentary conditions but is promoted by exercise. BCAA catabolism in muscle tissues is regulated by the branched-chain α-keto acid (BCKA dehydrogenase complex, which is inactivated by phosphorylation by BCKA dehydrogenase kinase (BDK. In the present study, we used muscle-specific BDK deficient mice (BDK-mKO mice to examine the effect of uncontrolled BCAA catabolism on endurance exercise performance and skeletal muscle energy metabolism. Untrained control and BDK-mKO mice showed the same performance; however, the endurance performance enhanced by 2 weeks of running training was somewhat, but significantly less in BDK-mKO mice than in control mice. Skeletal muscle of BDK-mKO mice had low levels of glycogen. Metabolome analysis showed that BCAA catabolism was greatly enhanced in the muscle of BDK-mKO mice and produced branched-chain acyl-carnitine, which induced perturbation of energy metabolism in the muscle. These results suggest that the tight regulation of BCAA catabolism in muscles is important for homeostasis of muscle energy metabolism and, at least in part, for adaptation to exercise training.

Homeostatic responses to amino acid insufficiency

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Tracy G. Anthony

2015-09-01

Full Text Available This article provides a brief overview describing how two key signaling pathways, namely the integrated stress response and the mammalian target of rapamycin complex 1, work together to facilitate cellular adaptation to dietary amino acid insufficiency. A deeper understanding of these mechanisms is leading to identification of novel targets which aid in disease treatments, improve stress recovery and increase health span through slowed aging and enhanced metabolic fitness.

The surface modification of polystyrene

International Nuclear Information System (INIS)

Tremlett, C.

2000-03-01

Polymers have ideal bulk properties for many applications. However, adhesion to many polymers is poor without surface pretreatment. This can result, for example, in peeling paint and printing, adhesive joint failure and bio-incompatibility. In applications such as painting, printing, adhesive bonding and biocompatibility, various cleaning or surface chemical modifications may be employed. A commodity polymer where pretreatment is sometimes needed is polystyrene. This project investigated, in detail, the effects of a novel method of modification namely mediated electrochemical oxidation (MEO), as a mode of surface modification on polystyrene and a comparison was made with other polymers. The resulting modification was investigated using a range of surface analysis techniques to obtain complementary information. These included, X-ray photoelectron spectroscopy, contact angles, static secondary ion mass spectrometry, atomic force microscopy, chemical derivatization, scanning electron microscopy, attenuated total reflection Fourier Transform infrared spectroscopy and composite lap shear joint testing. It has been shown that MEO modifies the surface of polystyrene introduced oxygen mainly as hydroxyl groups, and a small number of carbonyl groups, that are positioned only on the backbone hydrocarbon chain. This modification improved adhesion, was stable and samples could be stored in aqueous media. The resulting hydroxylation was further derivatized using an amino acid to provide a specialised surface. This was very different from the multiple oxygen functionalities introduced in the comparison studies by UV/ozone and plasma treatments. (author)

Plasma Amino Acid Abnormalities in Chronic Heart Failure. Mechanisms, Potential Risks and Targets in Human Myocardium Metabolism

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Roberto Aquilani

2017-11-01

Full Text Available The goal of this study was to measure arterial amino acid levels in patients with chronic heart failure (CHF, and relate them to left ventricular function and disease severity. Amino acids (AAs play a crucial role for heart protein-energy metabolism. In heart failure, arterial AAs, which are the major determinant of AA uptake by the myocardium, are rarely measured. Forty-one subjects with clinically stable CHF (New York Heart Association (NYHA class II to IV were analyzed. After overnight fasting, blood samples from the radial artery were taken to measure AA concentrations. Calorie (KcalI, protein-, fat-, carbohydrate-intake, resting energy expenditure (REE, total daily energy expenditure (REE × 1.3, and cardiac right catheterization variables were all measured. Eight matched controls were compared for all measurements, with the exception of cardiac catheterization. Compared with controls, CHF patients had reduced arterial AA levels, of which both their number and reduced rates are related to Heart Failure (HF severity. Arterial aspartic acid correlated with stroke volume index (r = 0.6263; p < 0.0001 and cardiac index (r = 0.4243; p = 0.0028. The value of arterial aspartic acid (µmol/L multiplied by the cardiac index was associated with left ventricular ejection fraction (r = 0.3765; p = 0.0076. All NYHA groups had adequate protein intake (≥1.1 g/kg/day and inadequate calorie intake (KcalI < REE × 1.3 was found only in class IV patients. This study showed that CHF patients had reduced arterial AA levels directly related to clinical disease severity and left ventricular dysfunction.

Prognostic Impact of Visceral Fat Amount and Branched-Chain Amino Acids (BCAA) in Hepatocellular Carcinoma.

Science.gov (United States)

Higashi, Takaaki; Hayashi, Hiromitsu; Kaida, Takayoshi; Arima, Kota; Takeyama, Hideaki; Taki, Katsunobu; Izumi, Daisuke; Tokunaga, Ryuma; Kosumi, Keisuke; Nakagawa, Shigeki; Okabe, Hirohisa; Imai, Katsunobu; Nitta, Hidetoshi; Hashimoto, Daisuke; Chikamoto, Akira; Beppu, Toru; Baba, Hideo

2015-12-01

Dysregulation of lipid and amino acid metabolism in patients with liver diseases results in obesity-related carcinogenesis and decreased levels of branched-chain amino acids (BCAA), respectively. This study assessed the clinical and prognostic impact of visceral fat amount (VFA) and its association with amino acid metabolism in patients with hepatocellular carcinoma (HCC). In this study, 215 patients who underwent hepatic resection for HCC were divided into two groups based on VFA criteria for metabolic abnormalities in Japan. Computed tomography was used to measure VFA at the third lumbar vertebra in the inferior direction. Of the 215 patients, 132 had high and 83 had low VFA. High VFA was significantly associated with older age and higher body mass index (BMI), subcutaneous fat amount, and BCAA, but not with liver function, nutrient status, or tumoral factors. VFA was positively correlated with BMI (P BCAA levels (P BCAA, serum albumin, and prognostic nutritional index were not. High VFA was associated with a high BCAA level, with high VFA prognostic of improved overall survival in Japanese patients with HCC.

Dynamic changes in amino acid concentration profiles in patients with sepsis.

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Longxiang Su

Full Text Available The goal of this work was to explore the dynamic concentration profiles of 42 amino acids and the significance of these profiles in relation to sepsis, with the aim of providing guidance for clinical therapies.Thirty-five critically ill patients with sepsis were included. These patients were further divided into sepsis (12 cases and severe sepsis (23 cases groups or survivor (20 cases and non-survivor (15 cases groups. Serum samples from the patients were collected on days 1, 3, 5, 7, 10, and 14 following intensive care unit (ICU admission, and the serum concentrations of 42 amino acids were measured.The metabolic spectrum of the amino acids changed dramatically in patients with sepsis. As the disease progressed further or with poor prognosis, the levels of the different amino acids gradually increased, decreased, or fluctuated over time. The concentrations of sulfur-containing amino acids (SAAs, especially taurine, decreased significantly as the severity of sepsis worsened or with poor prognosis of the patient. The serum concentrations of SAAs, especially taurine, exhibited weak negative correlations with the Sequential Organ Failure Assessment (SOFA (r=-0.319 and Acute Physiology and Chronic Health Evaluation (APACHE II (r=-0.325 scores. The areas under the receiver operating characteristic curves of cystine, taurine, and SAA levels and the SOFA and APACHE II scores, which denoted disease prognosis, were 0.623, 0.674, 0.678, 0.86, and 0.857, respectively.Critically ill patients with disorders of amino acid metabolism, especially of SAAs such as cystine and taurine, may provide an indicator of the need for the nutritional support of sepsis in the clinic.ClinicalTrial.gov identifier NCT01818830.

Genetics of homocysteine metabolism and associated disorders

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S. Brustolin

2010-01-01

Full Text Available Homocysteine is a sulfur-containing amino acid derived from the metabolism of methionine, an essential amino acid, and is metabolized by one of two pathways: remethylation or transsulfuration. Abnormalities of these pathways lead to hyperhomocysteinemia. Hyperhomocysteinemia is observed in approximately 5% of the general population and is associated with an increased risk for many disorders, including vascular and neurodegenerative diseases, autoimmune disorders, birth defects, diabetes, renal disease, osteoporosis, neuropsychiatric disorders, and cancer. We review here the correlation between homocysteine metabolism and the disorders described above with genetic variants on genes coding for enzymes of homocysteine metabolism relevant to clinical practice, especially common variants of the MTHFR gene, 677C>T and 1298A>C. We also discuss the management of hyperhomocysteinemia with folic acid supplementation and fortification of folic acid and the impact of a decrease in the prevalence of congenital anomalies and a decline in the incidence of stroke mortality.

Metabolomics changes in a rat model of obstructive jaundice: mapping to metabolism of amino acids, carbohydrates and lipids as well as oxidative stress.

Science.gov (United States)

Long, Yue; Dong, Xin; Yuan, Yawei; Huang, Jinqiang; Song, Jiangang; Sun, Yumin; Lu, Zhijie; Yang, Liqun; Yu, Weifeng

2015-07-01

The study examined the global metabolic and some biochemical changes in rats with cholestasis induced by bile duct ligation (BDL). Serum samples were collected in male Wistar rats with BDL (n = 8) and sham surgery (n = 8) at day 3 after surgery for metabolomics analysis using a combination of reversed phase chromatography and hydrophilic interaction chromatography (HILIC) and quadrupole-time-of-flight mass spectrometry (Q-TOF MS). The serum levels of malondialdehyde (MDA), total antioxidative capacity (T-AOC), glutathione (GSH) and glutathione disulfide (GSSG), the activities of superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) were measured to estimate the oxidative stress state. Key changes after BDL included increased levels of l-phenylalanine, l-glutamate, l-tyrosine, kynurenine, l-lactic acid, LysoPC(c) (14:0), glycine and succinic acid and decreased levels of l-valine, PC(b) (19:0/0:0), taurine, palmitic acid, l-isoleucine and citric acid metabolism products. And treatment with BDL significantly decreased the levels of GSH, T-AOC as well as SOD, GSH-Px activities, and upregulated MDA levels. The changes could be mapped to metabolism of amino acids and lipids, Krebs cycle and glycolysis, as well as increased oxidative stress and decreased antioxidant capability. Our study indicated that BDL induces major changes in the metabolism of all 3 major energy substances, as well as oxidative stress.

Production of L-valine from metabolically engineered Corynebacterium glutamicum.

Science.gov (United States)

Wang, Xiaoyuan; Zhang, Hailing; Quinn, Peter J

2018-05-01

L-Valine is one of the three branched-chain amino acids (valine, leucine, and isoleucine) essential for animal health and important in metabolism; therefore, it is widely added in the products of food, medicine, and feed. L-Valine is predominantly produced through microbial fermentation, and the production efficiency largely depends on the quality of microorganisms. In recent years, continuing efforts have been made in revealing the mechanisms and regulation of L-valine biosynthesis in Corynebacterium glutamicum, the most utilitarian bacterium for amino acid production. Metabolic engineering based on the metabolic biosynthesis and regulation of L-valine provides an effective alternative to the traditional breeding for strain development. Industrially competitive L-valine-producing C. glutamicum strains have been constructed by genetically defined metabolic engineering. This article reviews the global metabolic and regulatory networks responsible for L-valine biosynthesis, the molecular mechanisms of regulation, and the strategies employed in C. glutamicum strain engineering.

Effect of magnesium and of some trace elements on 14C incorporation in leaf sugars and amino acids of maize plants recovering after magnesium deficit stress

International Nuclear Information System (INIS)

Chichev, P.; Stoyanov, I.; Tungarov, G.

1977-01-01

The incorporation and distribution of 14 C in leaf free sugars and amino acids of maize plants under magnesium deficiency and following their recovery was studied by the aid of Mg applied singly or in combination with the trace elements Co, Cr, and B. It was established that stress resulting from magnesium deficit causes considerable changes in free sugar and amino acid metabolism. Magnesium deficiency reduces the relative share of sugars and raises the share of amino acids. It leads to great changes also in the ratio of the individual substances - reduces succrose, glutamic acid, and -amino butyric acid, increases fructose, rafinose, glucose, alanine, aspartic acid and valine. During a 10-day period of plant recovery the metabolic changes of free sugars and amino acids occurring as a result of magnesium deficit are restored to normal condition. Under the conditions existing in this experiment Mg was capable to restore alone disturbances in free sugar and amino acid metabolism to the level observed in the control plants. The trace elements Co, Cr and B, used in combination with Mg, had no marked additive effect on the recovery process of free sugar and amino acid metabolic disturbances caused by Mg deficiency. (author)

Quantification of underivatised amino acids on dry blood spot, plasma, and urine by HPLC-ESI-MS/MS.

Science.gov (United States)

Giordano, Giuseppe; Di Gangi, Iole Maria; Gucciardi, Antonina; Naturale, Mauro

2012-01-01

Enzyme deficiencies in amino acid (AA) metabolism affecting the levels of amino acids and their derivatives in physiological fluids may serve as diagnostically significant biomarkers for one or a group of metabolic disorders. Therefore, it is important to monitor a wide range of free amino acids simultaneously and to quantify them. This is time consuming if we use the classical methods and more than ever now that many laboratories have introduced Newborn Screening Programs for the semiquantitative analysis, detection, and quantification of some amino acids needed to be performed in a short time to reduce the rate of false positives.We have modified the stable isotope dilution HPLC-electrospray ionization (ESI)-MS/MS method previously described by Qu et al. (Anal Chem 74: 2034-2040, 2002) for a more rapid, robust, sensitive, and specific detection and quantification of underivatised amino acids. The modified method reduces the time of analysis to 10 min with very good reproducibility of retention times and a better separation of the metabolites and their isomers.The omission of the derivatization step allowed us to achieve some important advantages: fast and simple sample preparation and exclusion of artefacts and interferences. The use of this technique is highly sensitive, specific, and allows monitoring of 40 underivatized amino acids, including the key isomers and quantification of some of them, in order to cover many diagnostically important intermediates of metabolic pathways.We propose this HPLC-ESI-MS/MS method for underivatized amino acids as a support for the Newborn Screening as secondary test using the same dried blood spots for a more accurate and specific examination in case of suspected metabolic diseases. In this way, we avoid plasma collection from the patient as it normally occurs, reducing anxiety for the parents and further costs for analysis.The same method was validated and applied also to plasma and urine samples with good reproducibility

Degradation of fructans and production of propionic acid by Bacteroides thetaiotaomicron are enhanced by shortage of amino acids

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Signe eAdamberg

2014-12-01

Full Text Available Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by the catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory and levan (synthesized using levansucrase from Pseudomonas syringae, two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (DP > 3. Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h, followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of D-lactate (82 ± 33 mmol/gDW occurred in parallel with extensive consumption (up to 17 mmol/gDW of amino acids, especially Ser, Thr and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will be studied in

Targets to treat metabolic syndrome in polycystic ovary syndrome.

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Mahalingaiah, Shruthi; Diamanti-Kandarakis, Evanthia

2015-01-01

Metabolic syndrome is comprised of a combination of the following states: increased insulin resistance, dyslipidemia, cardiovascular disease, and increased abdominal obesity. Women with polycystic ovary syndrome (PCOS) have an increased risk of developing metabolic syndrome over the course of their lives. Metabolic syndrome increases risk of major cardiovascular events, morbidity, quality of life, and overall health care costs. Though metabolic syndrome in women with PCOS is an area of great concern, there is no effective individual medical therapeutic to adequately treat this issue. This article will review key aspects of metabolic syndrome in PCOS. We will discuss classic and novel therapeutics to address metabolic syndrome in women with PCOS. We will conclude with the importance of developing strategic interventions to increase the compliance to lifestyle and dietary modification, in addition to appreciation of the emerging pharmaceutical therapeutics available. Innovation in lifestyle modification, including diet, exercise, with and without dedicated stress reduction techniques is the future in treatment of metabolic syndrome in PCOS. Application of novel interventions, such as group medical care, may improve future adherence to lifestyle modification recommendations, in addition to or in combination with pharmaceutical therapeutics.

Targets to treat metabolic syndrome in polycystic ovary syndrome

Science.gov (United States)

Mahalingaiah, Shruthi; Diamanti-Kandarakis, Evanthia

2016-01-01

Introduction Metabolic syndrome is comprised of a combination of the following states: increased insulin resistance, dyslipidemia, cardiovascular disease, and increased abdominal obesity. Women with polycystic ovary syndrome (PCOS) have an increased risk of developing metabolic syndrome over the course of their lives. Metabolic syndrome increases risk of major cardiovascular events, morbidity, quality of life, and overall health care costs. Though metabolic syndrome in women with PCOS is an area of great concern, there is no effective individual medical therapeutic to adequately treat this issue. Areas Covered This article will review key aspects of metabolic syndrome in PCOS. We will discuss classic and novel therapeutics to address metabolic syndrome in women with PCOS. We will conclude with the importance of developing strategic interventions to increase the compliance to lifestyle and dietary modification, in addition to appreciation of the emerging pharmaceutical therapeutics available. Expert Opinion Innovation in lifestyle modification, including diet, exercise, with and without dedicated stress reduction techniques is the future in treatment of metabolic syndrome in PCOS. Application of novel interventions, such as group medical care, may improve future adherence to lifestyle modification recommendations, in addition to or in combination with pharmaceutical therapeutics. PMID:26488852

The effect of selected metals on the central metabolic pathways in ...

African Journals Online (AJOL)

compounds, interfere with xenobiotic metabolic pathways, and may also affect glycolysis, the Krebs cycle, oxidative phosphorylation, protein amino acid metabolism as well as carbohydrate and lipid metabolism. Therefore, in this review, we discuss the two phases of the central metabolic pathways, as well as how metals ...

Degradation of protein translation machinery by amino acid starvation-induced macroautophagy

DEFF Research Database (Denmark)

Gretzmeier, Christine; Eiselein, Sven; Johnson, Gregory R.

2017-01-01

, unbiased approaches relying on quantitative mass spectrometry-based proteomics. Macroautophagy is induced by rapamycin treatment, and by amino acid and glucose starvation in differentially, metabolically labeled cells. Protein dynamics are linked to image-based models of autophagosome turnover. Depending...... on the inducing stimulus, protein as well as organelle turnover differ. Amino acid starvation-induced macroautophagy leads to selective degradation of proteins important for protein translation. Thus, protein dynamics reflect cellular conditions in the respective treatment indicating stimulus-specific pathways...

The BsaHI restriction-modification system: Cloning, sequencing and analysis of conserved motifs

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Roberts Richard J

2008-05-01

Full Text Available Abstract Background Restriction and modification enzymes typically recognise short DNA sequences of between two and eight bases in length. Understanding the mechanism of this recognition represents a significant challenge that we begin to address for the BsaHI restriction-modification system, which recognises the six base sequence GRCGYC. Results The DNA sequences of the genes for the BsaHI methyltransferase, bsaHIM, and restriction endonuclease, bsaHIR, have been determined (GenBank accession #EU386360, cloned and expressed in E. coli. Both the restriction endonuclease and methyltransferase enzymes share significant similarity with a group of 6 other enzymes comprising the restriction-modification systems HgiDI and HgiGI and the putative HindVP, NlaCORFDP, NpuORFC228P and SplZORFNP restriction-modification systems. A sequence alignment of these homologues shows that their amino acid sequences are largely conserved and highlights several motifs of interest. We target one such conserved motif, reading SPERRFD, at the C-terminal end of the bsaHIR gene. A mutational analysis of these amino acids indicates that the motif is crucial for enzymatic activity. Sequence alignment of the methyltransferase gene reveals a short motif within the target recognition domain that is conserved among enzymes recognising the same sequences. Thus, this motif may be used as a diagnostic tool to define the recognition sequences of the cytosine C5 methyltransferases. Conclusion We have cloned and sequenced the BsaHI restriction and modification enzymes. We have identified a region of the R. BsaHI enzyme that is crucial for its activity. Analysis of the amino acid sequence of the BsaHI methyltransferase enzyme led us to propose two new motifs that can be used in the diagnosis of the recognition sequence of the cytosine C5-methyltransferases.

Genome scale engineering techniques for metabolic engineering.

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Liu, Rongming; Bassalo, Marcelo C; Zeitoun, Ramsey I; Gill, Ryan T

2015-11-01

Metabolic engineering has expanded from a focus on designs requiring a small number of genetic modifications to increasingly complex designs driven by advances in genome-scale engineering technologies. Metabolic engineering has been generally defined by the use of iterative cycles of rational genome modifications, strain analysis and characterization, and a synthesis step that fuels additional hypothesis generation. This cycle mirrors the Design-Build-Test-Learn cycle followed throughout various engineering fields that has recently become a defining aspect of synthetic biology. This review will attempt to summarize recent genome-scale design, build, test, and learn technologies and relate their use to a range of metabolic engineering applications. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Adrenaline and reactive oxygen species elicit proteome and energetic metabolism modifications in freshly isolated rat cardiomyocytes

International Nuclear Information System (INIS)

Costa, Vera Marisa; Silva, Renata; Tavares, Ludgero Canario; Vitorino, Rui; Amado, Francisco; Carvalho, Felix; Bastos, Maria de Lourdes; Carvalho, Marcia; Carvalho, Rui Albuquerque; Remiao, Fernando

2009-01-01

cytosolic NADH/NAD + ratio. Furthermore, an increase in manganese SOD expression and total SOD activity occurred in the ADR group, as the increase in the mitochondrial complexes presumably led to higher 'electron leakage'. The modifications in proteins, enzymes activity, and energetic metabolism were indicative that different pathways are activated by catecholamines and ROS. These alterations altogether determine the I/R and HF specific features and contribute for the initiation or aggravation of those cardiopathologic conditions.

Metabolic recycling of ammonia via glutamate dehydrogenase supports breast cancer biomass.

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Spinelli, Jessica B; Yoon, Haejin; Ringel, Alison E; Jeanfavre, Sarah; Clish, Clary B; Haigis, Marcia C

2017-11-17

Ammonia is a ubiquitous by-product of cellular metabolism; however, the biological consequences of ammonia production are not fully understood, especially in cancer. We found that ammonia is not merely a toxic waste product but is recycled into central amino acid metabolism to maximize nitrogen utilization. In our experiments, human breast cancer cells primarily assimilated ammonia through reductive amination catalyzed by glutamate dehydrogenase (GDH); secondary reactions enabled other amino acids, such as proline and aspartate, to directly acquire this nitrogen. Metabolic recycling of ammonia accelerated proliferation of breast cancer. In mice, ammonia accumulated in the tumor microenvironment and was used directly to generate amino acids through GDH activity. These data show that ammonia is not only a secreted waste product but also a fundamental nitrogen source that can support tumor biomass. Copyright © 2017, American Association for the Advancement of Science.

Insight into the adsorption of tetracycline onto amino and amino-Fe3+ gunctionalized mesoporous silica: Effect of functionalized groups.

Science.gov (United States)

Zhang, Ziyang; Li, Haiyan; Liu, Huijuan

2018-03-01

In order to study the influences of functionalized groups onto the adsorption of tetracycline, we prepared a series of amino and amino-Fe 3+ complex mesoporous silica adsorbents with diverse content of amino and Fe 3+ groups (named N,N-SBA15 and Fe-N,N-SBA15). The resulting mesoporous silica adsorbents were fully characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometer (FTIR) and N 2 adsorption/desorption isotherms. Furthermore, the effects of functionalized groups on the removal of TC were investigated. The results showed that the periodic ordered structure of SBA-15 was maintained after modification of amino/Fe 3+ groups. The functionalized amino groups decreased the adsorption capacity while the coordinated Fe 3+ increased the adsorption capacity. The adsorption kinetics of TC fitted pseudo-second-order model well and the equilibrium was achieved quickly. The adsorption isotherms fitted the Langmuir model well and with the Fe 3+ content increased from 3.93% to 8.26%, the Q max of the adsorbents increased from 102 to 188mmol/kg. The solution pH affected the adsorption of TC onto amino complex adsorbents slightly while influenced the adsorption onto Fe-amine complex adsorbents greatly. The adsorption of TC on SBA15 and N,N-SBA15 may be related to the formation of outer-sphere surface complexes, while the adsorption of TC onto Fe-N,N-SBA15 was mainly attributed to the inner-sphere surface complexes. This study could offer potential materials that have excellent adsorption behavior for environmental remediation and suggested useful information for the preparing other adsorbents in environmental applications. Copyright © 2017. Published by Elsevier B.V.

What is Nutrition & Metabolism?

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Feinman Richard D

2004-08-01

Full Text Available Abstract A new Open Access journal, Nutrition & Metabolism (N&M will publish articles that integrate nutrition with biochemistry and molecular biology. The open access process is chosen to provide rapid and accessible dissemination of new results and perspectives in a field that is of great current interest. Manuscripts in all areas of nutritional biochemistry will be considered but three areas of particular interest are lipoprotein metabolism, amino acids as metabolic signals, and the effect of macronutrient composition of diet on health. The need for the journal is identified in the epidemic of obesity, diabetes, dyslipidemias and related diseases, and a sudden increase in popular diets, as well as renewed interest in intermediary metabolism.

Genetically programmed expression of proteins containing the unnatural amino acid phenylselenocysteine

Science.gov (United States)

Wang, Jiangyun; Schultz, Peter G.

2010-09-07

The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate the unnatural amino acid phenylselenocysteine into proteins produced in eubacterial host cells such as E. coli. The invention provides, for example but not limited to, novel orthogonal aminoacyl-tRNA synthetases, polynucleotides encoding the novel synthetase molecules, methods for identifying and making the novel synthetases, methods for producing proteins containing the unnatural amino acid phenylselenocysteine and translation systems. The invention further provides methods for producing modified proteins (e.g., lipidated proteins) through targeted modification of the phenylselenocysteine residue in a protein.

[Modifications in myocardial energy metabolism in diabetic patients

Science.gov (United States)

Grynberg, A

2001-11-01

The capacity of cardiac myocyte to regulate ATP production to face any change in energy demand is a major determinant of cardiac function. Because FA is the main heart fuel (although the most expensive one in oxygen, and prompt to induce deleterious effects), this process is based on a balanced fatty acid (FA) metabolism. Several pathological situations are associated with an accumulation of FA or derivatives, or with an excessive b-oxidation. The diabetic cardiomyocyte is characterised by an over consumption of FA. The control of the FA/glucose balance clearly appears as a new strategy for cytoprotection, particularly in diabetes and requires a reduced FA contribution to ATP production. Cardiac myocytes can control FA mitochondrial entry, but display weak ability to control FA uptake, thus the fate of non beta-oxidized FA appear as a new impairment for the cell. Both the trigger and the regulation of cardiac contraction result from membrane activity, and the other major FA function in the myocardium is their role in membrane homeostasis, through the phospholipid synthesis and remodeling pathways. Sudden death, hypercatecholaminemia, diabetes and heart failure have been associated with an altered PUFA content in cardiac membranes. Experimental data suggest that the 2 metabolic pathways involved in membrane homeostasis may represent therapeutic targets for cytoprotection. The drugs that increase cardiac phospholipid turnover (trimétazidine, ranolazine,...) display anti-ischemic non hemodynamic effect. This effect is based on a redirection of FA utilization towards phospholipid synthesis, which decrease their availability for energy production. A nutritional approach gave also promising results. Besides its anti-arrhythmic effect, the dietary docosahexaenoic acid is able to reduce FA energy consumption and hence oxygen demand. The cardiac metabolic pathways involving FA should be considered as a whole, precariously balanced. The diabetic heart being characterised by

Effects of malting conditions on the amino acid compositions of final ...

African Journals Online (AJOL)

Administrator

2010-12-27

Dec 27, 2010 ... parameter to the yeast growth and metabolism in malt wort. To increase ... This study identified various important malting conditions that may lead to improvements in malt ... The difference in amino acid contents will affect beer.

Effects of dietary valine:lysine ratio on the performance, amino acid composition of tissues and mRNA expression of genes involved in branched-chain amino acid metabolism of weaned piglets

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Ye Tong Xu

2018-01-01

Full Text Available Objective The goal of this study was to investigate the effects of dietary standard ileal digestible (SID valine:lysine ratios on performance, intestinal morphology, amino acids of liver and muscle, plasma indices and mRNA expression of branched-chain amino acid (BCAA metabolism enzymes. Methods A total of 144 crossbred pigs (Duroc×Landrace×Large White weaned at 28±4 days of age (8.79±0.02 kg body weight were randomly allotted to 1 of 4 diets formulated to provide SID valine:lysine ratios of 50%, 60%, 70%, or 80%. Each diet was fed to 6 pens of pigs with 6 pigs per pen (3 gilts and 3 barrows for 28 days. Results Average daily gain increased quadratically (p<0.05, the villous height of the duodenum, jejunum and ileum increased linearly (p<0.05 as the SID valine:lysine ratio increased. The concentrations of plasma α-keto isovaleric and valine increased linearly (p<0.05, plasma aspartate, asparagine and cysteine decreased (p<0.05 as the SID valine:lysine ratio increased. An increase in SID lysine:valine levels increased mRNA expression levels of mitochondrial BCAA transaminase and branched-chain α-keto acid dehydrogenase in the longissimus dorsi muscle (p<0.05. Conclusion Using a quadratic model, a SID valine:lysine ratio of 68% was shown to maximize the growth of weaned pigs which is slightly higher than the level recommended by the National Research Council [6].

Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus): biochemical indication for limited carbohydrate utilization.

Science.gov (United States)

Rodríguez-Viera, Leandro; Perera, Erick; Montero-Alejo, Vivian; Perdomo-Morales, Rolando; García-Galano, Tsai; Martínez-Rodríguez, Gonzalo; Mancera, Juan M

2017-01-01

As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus . We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes.

Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus: biochemical indication for limited carbohydrate utilization

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Leandro Rodríguez-Viera

2017-11-01

Full Text Available As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus. We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes.

Amino acid catabolism-directed biofuel production in Clostridium sticklandii: An insight into model-driven systems engineering

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C Sangavai

2017-12-01

Full Text Available Model-driven systems engineering has been more fascinating process for the microbial production of biofuel and bio-refineries in chemical and pharmaceutical industries. Genome-scale modeling and simulations have been guided for metabolic engineering of Clostridium species for the production of organic solvents and organic acids. Among them, Clostridium sticklandii is one of the potential organisms to be exploited as a microbial cell factory for biofuel production. It is a hyper-ammonia producing bacterium and is able to catabolize amino acids as important carbon and energy sources via Stickland reactions and the development of the specific pathways. Current genomic and metabolic aspects of this bacterium are comprehensively reviewed herein, which provided information for learning about protein catabolism-directed biofuel production. It has a metabolic potential to drive energy and direct solventogenesis as well as acidogenesis from protein catabolism. It produces by-products such as ethanol, acetate, n-butanol, n-butyrate and hydrogen from amino acid catabolism. Model-driven systems engineering of this organism would improve the performance of the industrial sectors and enhance the industrial economy by using protein-based waste in environment-friendly ways. Keywords: Biofuel, Amino acid catabolism, Genome-scale model, Metabolic engineering, Systems biology, ABE fermentation, Clostridium sticklandii

New peptides players in metabolic disorders

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Agata Mierzwicka

2016-08-01

Full Text Available Among new peptides responsible for the pathogenesis of metabolic disorders and carbohydrate metabolism, adipokines are of great importance. Adipokines are substances of hormonal character, secreted by adipose tissue. Apart from the well-known adipokines, adropin and preptin are relatively newly discovered, hence their function is not fully understood. They are peptides not secreted by adipose tissue but their role in the metabolic regulations seems to be significant. Preptin is a 34-amino acid peptide, a derivative of proinsulin growth factor II (pro-IGF-II, secreted by pancreatic β cells, considered to be a physiological enhancer of insulin secretion. Additionally, preptin has a stimulating effect on osteoblasts, inducing their proliferation, differentiation and survival. Adropin is a 76-amino acid peptide, encoded by the energy homeostasis associated gene (Enho, mainly in liver and brain, and its expression is dependent on a diet. Adropin is believed to play an important role in metabolic homeostasis, fatty acids metabolism control, insulin resistance prevention, dyslipidemia, and impaired glucose tolerance. The results of studies conducted so far show that the diseases resulting from metabolic syndrome, such as obesity, type 2 diabetes mellitus, polycystic ovary syndrome, non-alcoholic fatty liver disease, or cardiovascular disease are accompanied by significant changes in the concentration of these peptides. It is also important to note that preptin has an anabolic effect on bone tissue, which might be preventive in osteoporosis.

Effects of an eight-week supervised, structured lifestyle modification programme on anthropometric, metabolic and cardiovascular risk factors in severely obese adults.

Science.gov (United States)

Crowe, Catherine; Gibson, Irene; Cunningham, Katie; Kerins, Claire; Costello, Caroline; Windle, Jane; O Shea, Paula M; Hynes, Mary; McGuire, Brian; Kilkelly, Katriona; Griffin, Helena; O Brien, Tim; Jones, Jenni; Finucane, Francis M

2015-08-01

Lifestyle modification is fundamental to obesity treatment, but few studies have described the effects of structured lifestyle programmes specifically in bariatric patients. We sought to describe changes in anthropometric and metabolic characteristics in a cohort of bariatric patients after participation in a nurse-led, structured lifestyle programme. We conducted a retrospective, observational cohort study of adults with a body mass index (BMI) ≥ 40 kgm(-2) (or ≥ 35 kgm(-2) with significant co-morbidity) who were attending a regional bariatric service and who completed a single centre, 8-week, nurse-led multidisciplinary lifestyle modification programme. Weight, height, waist circumference, blood pressure, HbA1c, fasting glucose and lipid profiles as well as functional capacity (Incremental Shuttle Walk Test) and questionnaire-based anxiety and depression scores before and after the programme were compared in per-protocol analyses. Of 183 bariatric patients enrolled, 150 (81.9%) completed the programme. Mean age of completers was 47.9 ± 1.2 years. 34.7% were male. There were statistically significant reductions in weight (129.6 ± 25.9 v 126.9 ± 26.1 kg, p triglyceride levels, with an increase in functional capacity (5.9 ± 1.7 v 6.8 ± 2.1 metabolic equivalents of thermogenesis (METS), p structured lifestyle programme had improved adiposity, fitness, lipid profiles, psychosocial health, blood pressure and glycaemia. Further assessment of this programme in a pragmatic randomised controlled trial seems warranted.

BCAA Metabolism and NH3 Homeostasis.

Science.gov (United States)

Conway, M E; Hutson, S M

2016-01-01

The branched chain amino acids (BCAA) are essential amino acids required not only for growth and development, but also as nutrient signals and as nitrogen donors to neurotransmitter synthesis and glutamate/glutamine cycling. Transamination and oxidative decarboxylation of the BCAAs are catalysed by the branched-chain aminotransferase proteins (BCATm, mitochondrial and BCATc, cytosolic) and the branched-chain α-keto acid dehydrogenase enzyme complex (BCKDC), respectively. These proteins show tissue, cell compartmentation, and protein-protein interactions, which call for substrate shuttling or channelling and nitrogen transfer for oxidation to occur. Efficient regulation of these pathways is mediated through the redox environment and phosphorylation in response to dietary and hormonal stimuli. The wide distribution of these proteins allows for effective BCAA utilisation. We discuss how BCAT, BCKDC, and glutamate dehydrogenase operate in supramolecular complexes, allowing for efficient channelling of substrates. The role of BCAAs in brain metabolism is highlighted in rodent and human brain, where differential expression of BCATm indicates differences in nitrogen metabolism between species. Finally, we introduce a new role for BCAT, where a change in function is triggered by oxidation of its redox-active switch. Our understanding of how BCAA metabolism and nitrogen transfer is regulated is important as many studies now point to BCAA metabolic dysregulation in metabolic and neurodegenerative conditions.

An allostatic mechanism for M2 pyruvate kinase as an amino-acid sensor.

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Yuan, Meng; McNae, Iain W; Chen, Yiyuan; Blackburn, Elizabeth A; Wear, Martin A; Michels, Paul A M; Fothergill-Gilmore, Linda A; Hupp, Ted; Walkinshaw, Malcolm D

2018-05-10

We have tested the effect of all 20 proteinogenic amino acids on the activity of the M2 isoenzyme of pyruvate kinase (M2PYK) and show that within physiologically relevant concentrations, phenylalanine, alanine, tryptophan, methionine, valine, and proline act as inhibitors while histidine and serine act as activators. Size exclusion chromatography has been used to show that all amino acids, whether activators or inhibitors, stabilise the tetrameric form of M2PYK. In the absence of amino-acid ligands an apparent tetramer-monomer dissociation K d is estimated to be ~0.9 µM with a slow dissociation rate (t 1/2 ~ 15 min). X-ray structures of M2PYK complexes with alanine, phenylalanine, and tryptophan show the M2PYK locked in an inactive T-state conformation, while activators lock the M2PYK tetramer in the active R-state conformation. Amino-acid binding in the allosteric pocket triggers rigid body rotations (11°) stabilising either T or R-states. The opposing inhibitory and activating effects of the non-essential amino acids serine and alanine suggest that M2PYK could act as a rapid-response nutrient sensor to rebalance cellular metabolism. This competition at a single allosteric site between activators and inhibitors provides a novel regulatory mechanism by which M2PYK activity is finely tuned by the relative (but not absolute) concentrations of activator and inhibitor amino acids. Such 'allostatic' regulation may be important in metabolic reprogramming and influencing cell fate. ©2018 The Author(s).

Effect of dietary starch level and high rumen-undegradable protein on endocrine-metabolic status, milk yield, and milk composition in dairy cows during early and late lactation.

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Piccioli-Cappelli, F; Loor, J J; Seal, C J; Minuti, A; Trevisi, E

2014-12-01

Diet composition defines the amount and type of nutrients absorbed by dairy cows. Endocrine-metabolic interactions can influence these parameters, and so nutrient availability for the mammary gland can significantly vary and affect milk yield and its composition. Six dairy cows in early and then late lactation received, for 28 d in a changeover design, 2 diets designed to provide, within the same stage of lactation, similar amounts of rumen fermentable material but either high starch plus sugar (HS) content or low starch plus sugar content (LS). All diets had similar dietary crude protein and calculated supply of essential amino acids. Dry matter intake within each stage of lactation was similar between groups. Milk yield was similar between groups in early lactation, whereas a higher milk yield was observed in late lactation when feeding HS. At the metabolic level, the main difference observed between the diets in both stages of lactation was lower blood glucose in cows fed LS. The lower glucose availability during consumption of LS caused substantial modifications in the circulating and postprandial pattern of metabolic hormones. Feeding LS versus HS resulted in an increase in the ratio of bovine somatotropin to insulin. This increased mobilization of lipid reserves resulted in higher blood concentrations of nonesterified fatty acids and β-hydroxybutyrate, which contributed to the higher milk fat content in both stages of lactation in the LS group. This greater recourse to body fat stores was confirmed by the greater loss of body weight during early lactation and the slower recovery of body weight in late lactation in cows fed LS. The lower insulin to glucagon ratio observed in cows fed LS in early and late lactation likely caused an increase in hepatic uptake and catabolism of amino acids, as confirmed by the higher blood urea concentrations. Despite the higher catabolism of amino acids in LS in early lactation, similar milk protein output was observed for both

Clinical neurogenetics: neurologic presentations of metabolic disorders.

Science.gov (United States)

Kwon, Jennifer M; D'Aco, Kristin E

2013-11-01

This article reviews aspects of the neurologic presentations of selected treatable inborn errors of metabolism within the category of small molecule disorders caused by defects in pathways of intermediary metabolism. Disorders that are particularly likely to be seen by neurologists include those associated with defects in amino acid metabolism (organic acidemias, aminoacidopathies, urea cycle defects). Other disorders of small molecule metabolism are discussed as additional examples in which early treatments have the potential for better outcomes. Copyright © 2013 Elsevier Inc. All rights reserved.

Plasma metabolomics reveal the correlation of metabolic pathways and Prakritis of humans

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Amey Shirolkar

2018-04-01

Full Text Available Background: Ayurveda, an ancient Indian medicinal system, has categorized human body constitutions in three broad constitutional types (prakritis i.e. Vata, Pitta and Kapha. Objectives: Analysis of plasma metabolites and related pathways to classify Prakriti specific dominant marker metabolites and metabolic pathways. Materials and methods: 38 healthy male individuals were assessed for dominant Prakritis and their fasting blood samples were collected. The processed plasma samples were subjected to rapid resolution liquid chromatography–electrospray ionization–quadrupole time of flight mass spectrometry (RRLC–ESI–QTOFMS. Mass profiles were aligned and subjected to multivariate analysis. Results: Partial least square discriminant analysis (PLS-DA model showed 97.87% recognition capability. List of PLS-DA metabolites was subjected to permutative Benjamini–Hochberg false discovery rate (FDR correction and final list of 76 metabolites with p  2.0 was identified. Pathway analysis using metascape and JEPETTO plugins in Cytoscape revealed that steroidal hormone biosynthesis, amino acid, and arachidonic acid metabolism are major pathways varying with different constitution. Biological Go processes analysis showed that aromatic amino acids, sphingolipids, and pyrimidine nucleotides metabolic processes were dominant in kapha type of body constitution. Fat soluble vitamins, cellular amino acid, and androgen biosynthesis process along with branched chain amino acid and glycerolipid catabolic processes were dominant in pitta type individuals. Vata Prakriti was found to have dominant catecholamine, arachidonic acid and hydrogen peroxide metabolomics processes. Conclusion: The neurotransmission and oxidative stress in vata, BCAA catabolic, androgen, xenobiotics metabolic processes in pitta, and aromatic amino acids, sphingolipid, and pyrimidine metabolic process in kapha Prakriti were the dominant marker pathways. Keywords: Ayurveda, Prakriti, Human

Alterations in Aspergillus brasiliensis (niger) ATCC 9642 membranes associated to metabolism modifications during application of low-intensity electric current.

Science.gov (United States)

Velasco-Alvarez, Nancy; Gutiérrez-Rojas, Mariano; González, Ignacio

2017-12-01

The effects of electric current on membranes associated with metabolism modifications in Aspergillus brasiliensis (niger) ATCC 9642 were studied. A 450-mL electrochemical cell with titanium ruthenium-oxide coated electrodes and packed with 15g of perlite, as inert support, was inoculated with A. brasiliensis spores and incubated in a solid inert-substrate culture (12 d; 30°C). Then, 4.5days after starting the culture, a current of 0.42mAcm -2 was applied for 24h. The application of low-intensity electric current increased the molecular oxygen consumption rate in the mitochondrial respiratory chain, resulting in high concentrations of reactive oxygen species, promoting high lipoperoxidation levels, according to measured malondialdehyde, and consequent alterations in membrane permeability explained the high n-hexadecane (HXD) degradation rates observed here (4.7-fold higher than cultures without current). Finally, cell differentiation and spore production were strongly stimulated. The study contributes to the understanding of the effect of current on the cell membrane and its association with HXD metabolism. Copyright © 2017. Published by Elsevier B.V.

Influence of the Amino Acid Sequence on Protein-Mineral Interactions in Soil

Science.gov (United States)

Chacon, S. S.; Reardon, P. N.; Purvine, S.; Lipton, M. S.; Washton, N.; Kleber, M.

2017-12-01

The intimate associations between protein and mineral surfaces have profound impacts on nutrient cycling in soil. Proteins are an important source of organic C and N, and a subset of proteins, extracellular enzymes (EE), can catalyze the depolymerization of soil organic matter (SOM). Our goal was to determine how variation in the amino acid sequence could influence a protein's susceptibility to become chemically altered by mineral surfaces to infer the fate of adsorbed EE function in soil. We hypothesized that (1) addition of charged amino acids would enhance the adsorption onto oppositely charged mineral surfaces (2) addition of aromatic amino acids would increase adsorption onto zero charged surfaces (3) Increase adsorption of modified proteins would enhance their susceptibility to alterations by redox active minerals. To test these hypotheses, we generated three engineered proxies of a model protein Gb1 (IEP 4.0, 6.2 kDA) by inserting either negatively charged, positively charged or aromatic amino acids in the second loop. These modified proteins were allowed to interact with functionally different mineral surfaces (goethite, montmorillonite, kaolinite and birnessite) at pH 5 and 7. We used LC-MS/MS and solution-state Heteronuclear Single Quantum Coherence Spectroscopy NMR to observe modifications on engineered proteins as a consequence to mineral interactions. Preliminary results indicate that addition of any amino acids to a protein increase its susceptibility to fragmentation and oxidation by redox active mineral surfaces, and alter adsorption to the other mineral surfaces. This suggest that not all mineral surfaces in soil may act as sorbents for EEs and chemical modification of their structure should also be considered as an explanation for decrease in EE activity. Fragmentation of proteins by minerals can bypass the need to produce proteases, but microbial acquisition of other nutrients that require enzymes such as cellulases, ligninases or phosphatases

Interactions between epigenetics and metabolism in cancers

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Jihye eYun

2012-11-01

Full Text Available Cancer progression is accompanied by widespread transcriptional changes and metabolic alterations. Although it is widely accepted that the origin of cancer can be traced to the mutations that accumulate over time, relatively recent evidence favors a similarly fundamental role for alterations in the epigenome during tumorigenesis. Changes in epigenetics that arise from post-translational modifications of histones and DNA, are exploited by cancer cells to upregulate and/or downregulate the expression levels of oncogenes and tumor suppressors, respectively. Although the mechanisms behind these modifications, in particular how they lead to gene silencing and activation, are still being understood, many enzymes that carry out post-translational modifications that alter epigenetics require metabolites as substrates or cofactors. As a result, their activities can be influenced by the metabolic state of the cell. The purpose of this review is to give an overview of cancer epigenetics and metabolism and provide examples of where they converge.

Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids

International Nuclear Information System (INIS)

Woods, L.L.; Mizelle, H.L.; Montani, J.P.; Hall, J.E.

1986-01-01

Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na + is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na + reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O 2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na + delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized α-aminoisobutyric acid into NK produced changes in renal hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur

Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids

Energy Technology Data Exchange (ETDEWEB)

Woods, L.L.; Mizelle, H.L.; Montani, J.P.; Hall, J.E.

1986-08-01

Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized -aminoisobutyric acid into NK produced changes in renal hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur.

Impact of Wort Amino Acids on Beer Flavour: A Review

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Inês M. Ferreira

2018-03-01

Full Text Available The process by which beer is brewed has not changed significantly since its discovery thousands of years ago. Grain is malted, dried, crushed and mixed with hot water to produce wort. Yeast is added to the sweet, viscous wort, after which fermentation occurs. The biochemical events that occur during fermentation reflect the genotype of the yeast strain used, and its phenotypic expression is influenced by the composition of the wort and the conditions established in the fermenting vessel. Although wort is complex and not completely characterized, its content in amino acids indubitably affects the production of some minor metabolic products of fermentation which contribute to the flavour of beer. These metabolic products include higher alcohols, esters, carbonyls and sulfur-containing compounds. The formation of these products is comprehensively reviewed in this paper. Furthermore, the role of amino acids in the beer flavour, in particular their relationships with flavour active compounds, is discussed in light of recent data.

Fifteen years experience: Egyptian metabolic lab | Fateen | Egyptian ...

African Journals Online (AJOL)

Those patients were classified as: 722 patients (69.4%) with lysosomal storage disorders, 302 patients (29%) with amino acid disorders and 17 patients (1.6%) with galactosemia. Conclusion: This study illustrates the experience of the reference metabolic lab in Egypt over 15 years. The lab began metabolic disorder ...

Enzymes of energy metabolism in hatchlings of amazonian freshwater turtles (Testudines, Podocnemididae

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WP. Duncan

Full Text Available The metabolic profiles of selected tissues were analyzed in hatchlings of the Amazonian freshwater turtles Podocnemis expansa, P. unifilis and P. sextuberculata. Metabolic design in these species was judged based on the key enzymes of energy metabolism, with special emphasis on carbohydrate, lipid, amino acid and ketone body metabolism. All species showed a high glycolytic potential in all sampled tissues. Based on low levels of hexokinase, glycogen may be an important fuel for these species. The high lactate dehydrogenase activity in the liver may play a significant role in carbohydrate catabolism, possibly during diving. Oxidative metabolism in P. sextuberculata appears to be designed for the use of lipids, amino acids and ketone bodies. The maximal activities of 3-hydroxyacyl-CoA dehydrogenase, malate dehydrogenase, glutamine dehydrogenase, alanine aminotransferase and succinyl-CoA keto transferase display high aerobic potential, especially in muscle and liver tissues of this species. Although amino acids and ketone bodies may be important fuels for oxidative metabolism, carbohydrates and lipids are the major fuels used by P. expansa and P. unifilis. Our results are consistent with the food habits and lifestyle of Amazonian freshwater turtles. The metabolic design, based on enzyme activities, suggests that hatchlings of P. unifilis and P. expansa are predominately herbivorous, whereas P. sextuberculata rely on a mixed diet of animal matter and vegetation.

NMR-based metabonomic analyses of the effects of ultrasmall superparamagnetic particles of iron oxide (USPIO) on macrophage metabolism

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Feng, Jianghua; Zhao, Jing; Hao, Fuhua; Chen, Chang; Bhakoo, Kishore; Tang, Huiru

2011-05-01

The metabonomic changes in murine RAW264.7 macrophage-like cell line induced by ultrasmall superparamagnetic particles of iron oxides (USPIO) have been investigated, by analyzing both the cells and culture media, using high-resolution NMR in conjunction with multivariate statistical methods. Upon treatment with USPIO, macrophage cells showed a significant decrease in the levels of triglycerides, essential amino acids such as valine, isoleucine, and choline metabolites together with an increase of glycerophospholipids, tyrosine, phenylalanine, lysine, glycine, and glutamate. Such cellular responses to USPIO were also detectable in compositional changes of cell media, showing an obvious depletion of the primary nutrition molecules, such as glucose and amino acids and the production of end-products of glycolysis, such as pyruvate, acetate, and lactate and intermediates of TCA cycle such as succinate and citrate. At 48 h treatment, there was a differential response to incubation with USPIO in both cell metabonome and medium components, indicating that USPIO are phagocytosed and released by macrophages. Furthermore, information on cell membrane modification can be derived from the changes in choline-like metabolites. These results not only suggest that NMR-based metabonomic methods have sufficient sensitivity to identify the metabolic consequences of murine RAW264.7 macrophage-like cell line response to USPIO in vitro, but also provide useful information on the effects of USPIO on cellular metabolism.

NMR-based metabonomic analyses of the effects of ultrasmall superparamagnetic particles of iron oxide (USPIO) on macrophage metabolism

International Nuclear Information System (INIS)

Feng Jianghua; Zhao Jing; Hao Fuhua; Chen Chang; Bhakoo, Kishore; Tang, Huiru

2011-01-01

The metabonomic changes in murine RAW264.7 macrophage-like cell line induced by ultrasmall superparamagnetic particles of iron oxides (USPIO) have been investigated, by analyzing both the cells and culture media, using high-resolution NMR in conjunction with multivariate statistical methods. Upon treatment with USPIO, macrophage cells showed a significant decrease in the levels of triglycerides, essential amino acids such as valine, isoleucine, and choline metabolites together with an increase of glycerophospholipids, tyrosine, phenylalanine, lysine, glycine, and glutamate. Such cellular responses to USPIO were also detectable in compositional changes of cell media, showing an obvious depletion of the primary nutrition molecules, such as glucose and amino acids and the production of end-products of glycolysis, such as pyruvate, acetate, and lactate and intermediates of TCA cycle such as succinate and citrate. At 48 h treatment, there was a differential response to incubation with USPIO in both cell metabonome and medium components, indicating that USPIO are phagocytosed and released by macrophages. Furthermore, information on cell membrane modification can be derived from the changes in choline-like metabolites. These results not only suggest that NMR-based metabonomic methods have sufficient sensitivity to identify the metabolic consequences of murine RAW264.7 macrophage-like cell line response to USPIO in vitro, but also provide useful information on the effects of USPIO on cellular metabolism.

Functional group and stereochemical requirements for substrate binding by ghrelin O-acyltransferase revealed by unnatural amino acid incorporation.

Science.gov (United States)

Cleverdon, Elizabeth R; Davis, Tasha R; Hougland, James L

2018-04-21

Ghrelin is a small peptide hormone that undergoes a unique posttranslational modification, serine octanoylation, to play its physiological roles in processes including hunger signaling and glucose metabolism. Ghrelin O-acyltransferase (GOAT) catalyzes this posttranslational modification, which is essential for ghrelin to bind and activate its cognate GHS-R1a receptor. Inhibition of GOAT offers a potential avenue for modulating ghrelin signaling for therapeutic effect. Defining the molecular characteristics of ghrelin that lead to binding and recognition by GOAT will facilitate the development and optimization of GOAT inhibitors. We show that small peptide mimics of ghrelin substituted with 2,3-diaminopropanoic acid in place of the serine at the site of octanoylation act as submicromolar inhibitors of GOAT. Using these chemically modified analogs of desacyl ghrelin, we define key functional groups within the N-terminal sequence of ghrelin essential for binding to GOAT and determine GOAT's tolerance to backbone methylations and altered amino acid stereochemistry within ghrelin. Our study provides a structure-activity analysis of ghrelin binding to GOAT that expands upon activity-based investigations of ghrelin recognition and establishes a new class of potent substrate-mimetic GOAT inhibitors for further investigation and therapeutic interventions targeting ghrelin signaling. Copyright © 2018 Elsevier Inc. All rights reserved.

Metabolic effects of keto acid--amino acid supplementation in patients with chronic renal insufficiency receiving a low-protein diet and recombinant human erythropoietin--a randomized controlled trial.

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Teplan, V; Schück, O; Votruba, M; Poledne, R; Kazdová, L; Skibová, J; Malý, J

2001-09-17

Supplement with keto acids/amino acids (KA) and erythropoietin can independently improve the metabolic sequels of chronic renal insufficiency. Our study was designed to establish whether a supplementation with keto acids/amino acids (KA) exerts additional beneficial metabolic effects in patients with chronic renal insufficiency (CRF) treated with a low-protein diet (LPD) and recombinant human erythropoietin (EPO). In a prospective randomized controlled trial over a period of 12 months, we evaluated a total of 38 patients (20 M/18 F) aged 32-68 years with a creatinine clearance (CCr) of 20-36 ml/min. All patients were receiving EPO (40 U/kg twice a week s.c.) and a low-protein diet (0.6 g protein/kg/day and 145 kJ/kg/day). The diet of 20 patients (Group I) was supplemented with KA at a dosage of 100 mg/kg/day while 18 patients (Group II) received no supplementation. During the study period, the glomerular filtration rate slightly decreased (CCr from 28.2 +/- 3.4 to 26.4 +/- 4.1 ml/min and 29.6 +/- 4.8 to 23.4 +/- 4.4 ml/min in groups I and II, respectively and Cin); this however was more marked in Group II (Group I vs. Group II, p diet presents an effective treatment modality in the conservative management of CRF.

Global metabolic analyses identify key differences in metabolite levels between polymyxin-susceptible and polymyxin-resistant Acinetobacter baumannii.

Science.gov (United States)

Maifiah, Mohd Hafidz Mahamad; Cheah, Soon-Ee; Johnson, Matthew D; Han, Mei-Ling; Boyce, John D; Thamlikitkul, Visanu; Forrest, Alan; Kaye, Keith S; Hertzog, Paul; Purcell, Anthony W; Song, Jiangning; Velkov, Tony; Creek, Darren J; Li, Jian

2016-02-29

Multidrug-resistant Acinetobacter baumannii presents a global medical crisis and polymyxins are used as the last-line therapy. This study aimed to identify metabolic differences between polymyxin-susceptible and polymyxin-resistant A. baumannii using untargeted metabolomics. The metabolome of each A. baumannii strain was measured using liquid chromatography-mass spectrometry. Multivariate and univariate statistics and pathway analyses were employed to elucidate metabolic differences between the polymyxin-susceptible and -resistant A. baumannii strains. Significant differences were identified between the metabolic profiles of the polymyxin-susceptible and -resistant A. baumannii strains. The lipopolysaccharide (LPS) deficient, polymyxin-resistant 19606R showed perturbation in specific amino acid and carbohydrate metabolites, particularly pentose phosphate pathway (PPP) and tricarboxylic acid (TCA) cycle intermediates. Levels of nucleotides were lower in the LPS-deficient 19606R. Furthermore, 19606R exhibited a shift in its glycerophospholipid profile towards increased abundance of short-chain lipids compared to the parent polymyxin-susceptible ATCC 19606. In contrast, in a pair of clinical isolates 03-149.1 (polymyxin-susceptible) and 03-149.2 (polymyxin-resistant, due to modification of lipid A), minor metabolic differences were identified. Notably, peptidoglycan biosynthesis metabolites were significantly depleted in both of the aforementioned polymyxin-resistant strains. This is the first comparative untargeted metabolomics study to show substantial differences in the metabolic profiles of the polymyxin-susceptible and -resistant A. baumannii.

Assays of D-Amino Acid Oxidase Activity

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Elena Rosini

2018-01-01

Full Text Available D-amino acid oxidase (DAAO is a well-known flavoenzyme that catalyzes the oxidative FAD-dependent deamination of D-amino acids. As a result of the absolute stereoselectivity and broad substrate specificity, microbial DAAOs have been employed as industrial biocatalysts in the production of semi-synthetic cephalosporins and enantiomerically pure amino acids. Moreover, in mammals, DAAO is present in specific brain areas and degrades D-serine, an endogenous coagonist of the N-methyl-D-aspartate receptors (NMDARs. Dysregulation of D-serine metabolism due to an altered DAAO functionality is related to pathological NMDARs dysfunctions such as in amyotrophic lateral sclerosis and schizophrenia. In this protocol paper, we describe a variety of direct assays based on the determination of molecular oxygen consumption, reduction of alternative electron acceptors, or α-keto acid production, of coupled assays to detect the hydrogen peroxide or the ammonium production, and an indirect assay of the α-keto acid production based on a chemical derivatization. These analytical assays allow the determination of DAAO activity both on recombinant enzyme preparations, in cells, and in tissue samples.

Designing and Producing Modified, New-to-Nature Peptides with Antimicrobial Activity by Use of a Combination of Various Lantibiotic Modification Enzymes

NARCIS (Netherlands)

van Heel, Auke J.; Mu, Dongdong; Montalban-Lopez, Manuel; Hendriks, Djoke; Kuipers, Oscar P.

Lanthipeptides are peptides that contain several post-translationally modified amino acid residues and commonly show considerable antimicrobial activity. After translation, the amino acid residues of these peptides are modified by a distinct set of modification enzymes. This process results in

Genetic analysis of central carbon metabolism unveils an amino acid substitution that alters maize NAD-dependent isocitrate dehydrogenase activity.

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Nengyi Zhang

2010-04-01

Full Text Available Central carbon metabolism (CCM is a fundamental component of life. The participating genes and enzymes are thought to be structurally and functionally conserved across and within species. Association mapping utilizes a rich history of mutation and recombination to achieve high resolution mapping. Therefore, applying association mapping in maize (Zea mays ssp. mays, the most diverse model crop species, to study the genetics of CCM is a particularly attractive system.We used a maize diversity panel to test the CCM functional conservation. We found heritable variation in enzyme activity for every enzyme tested. One of these enzymes was the NAD-dependent isocitrate dehydrogenase (IDH, E.C. 1.1.1.41, in which we identified a novel amino-acid substitution in a phylogenetically conserved site. Using candidate gene association mapping, we identified that this non-synonymous polymorphism was associated with IDH activity variation. The proposed mechanism for the IDH activity variation includes additional components regulating protein level. With the comparison of sequences from maize and teosinte (Zea mays ssp. Parviglumis, the maize wild ancestor, we found that some CCM genes had also been targeted for selection during maize domestication.Our results demonstrate the efficacy of association mapping for dissecting natural variation in primary metabolic pathways. The considerable genetic diversity observed in maize CCM genes underlies heritable phenotypic variation in enzyme activities and can be useful to identify putative functional sites.

Slc3a2 Mediates Branched-Chain Amino-Acid-Dependent Maintenance of Regulatory T Cells

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Kayo Ikeda

2017-11-01

Full Text Available Summary: Foxp3+ regulatory T (Treg cells, which suppress immune responses, are highly proliferative in vivo. However, it remains unclear how the active replication of Treg cells is maintained in vivo. Here, we show that branched-chain amino acids (BCAAs, including isoleucine, are required for maintenance of the proliferative state of Treg cells via the amino acid transporter Slc3a2-dependent metabolic reprogramming. Mice fed BCAA-reduced diets showed decreased numbers of Foxp3+ Treg cells with defective in vivo proliferative capacity. Mice lacking Slc3a2 specifically in Foxp3+ Treg cells showed impaired in vivo replication and decreased numbers of Treg cells. Slc3a2-deficient Treg cells showed impaired isoleucine-induced activation of the mTORC1 pathway and an altered metabolic state. Slc3a2 mutant mice did not show an isoleucine-induced increase of Treg cells in vivo and exhibited multi-organ inflammation. Taken together, these findings demonstrate that BCAA controls Treg cell maintenance via Slc3a2-dependent metabolic regulation. : Treg cells regulate excess immune responses and are highly proliferative in vivo. Ikeda et al. find that branched-chain amino acids (BCAAs are essentially required to maintain expansion and the suppressive capacity of Treg cells via Slc3a2 and mTORC1. Keywords: Treg cells, amino acids, immunometabolism, immune regulation, transporter

Metabolic Diseases Downregulate the Majority of Histone Modification Enzymes, Making a Few Upregulated Enzymes Novel Therapeutic Targets – “Sand out and Gold Stays”

Science.gov (United States)

Shao, Ying; Chernaya, Valeria; Johnson, Candice; Yang, William Y.; Cueto, Ramon; Sha, Xiaojin; Zhang, Yi; Qin, Xuebin; Sun, Jianxin; Choi, Eric T.; Wang, Hong; Yang, Xiao-feng

2016-01-01

To determine whether the expression of histone modification enzymes is regulated in physiological and pathological conditions, we took an experimental database mining approach pioneered in our labs to determine a panoramic expression profile of 164 enzymes in 19 human and 17 murine tissues. We have made the following significant findings: 1) Histone enzymes are differentially expressed in cardiovascular, immune and other tissues; 2) Our new pyramid model showed that heart and T cells are among a few tissues in which histone acetylation/deacetylation, histone methylation/demethylation are in the highest varieties; and 3) Histone enzymes are more downregulated than upregulated in metabolic diseases and Treg polarization/differentiation, but not in tumors. These results have demonstrated a new working model of “sand out and gold stays,” where more downregulation than upregulation of histone enzymes in metabolic diseases makes a few upregulated enzymes the potential novel therapeutic targets in metabolic diseases and Treg activity. PMID:26746407

Plasma concentrations of water.soluble vitamins in metabolic ...

African Journals Online (AJOL)

Context: Vitamins B1 (thiamine), B3 (niacin), B6 (pyridoxine), and C (ascorbic acid) are vital for energy, carbohydrate, lipid, and amino acid metabolism and in the regulation of the cellular redox state. Some studies have associated low levels of water.soluble vitamins with metabolic syndrome and its various components.

Integrated proteomics and metabolomics suggests symbiotic metabolism and multimodal regulation in a fungal-endobacterial system.

Science.gov (United States)

Li, Zhou; Yao, Qiuming; Dearth, Stephen P; Entler, Matthew R; Castro Gonzalez, Hector F; Uehling, Jessie K; Vilgalys, Rytas J; Hurst, Gregory B; Campagna, Shawn R; Labbé, Jessy L; Pan, Chongle

2017-03-01

Many plant-associated fungi host endosymbiotic endobacteria with reduced genomes. While endobacteria play important roles in these tri-partite plant-fungal-endobacterial systems, the active physiology of fungal endobacteria has not been characterized extensively by systems biology approaches. Here, we use integrated proteomics and metabolomics to characterize the relationship between the endobacterium Mycoavidus sp. and the root-associated fungus Mortierella elongata. In nitrogen-poor media, M. elongata had decreased growth but hosted a large and growing endobacterial population. The active endobacterium likely extracted malate from the fungal host as the primary carbon substrate for energy production and biosynthesis of phospho-sugars, nucleobases, peptidoglycan and some amino acids. The endobacterium obtained nitrogen by importing a variety of nitrogen-containing compounds. Further, nitrogen limitation significantly perturbed the carbon and nitrogen flows in the fungal metabolic network. M. elongata regulated many pathways by concordant changes on enzyme abundances, post-translational modifications, reactant concentrations and allosteric effectors. Such multimodal regulations may be a general mechanism for metabolic modulation. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Seawater cultivation of freshwater cyanobacterium Synechocystis sp. PCC 6803 drastically alters amino acid composition and glycogen metabolism

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Hiroko eIijima

2015-04-01

Full Text Available Water use assessment is important for bioproduction using cyanobacteria. For eco-friendly reasons, seawater should preferably be used for cyanobacteria cultivation instead of freshwater. In this study, we demonstrated that the freshwater unicellular cyanobacterium Synechocystis sp. PCC 6803 could be grown in a medium based on seawater. The Synechocystis wild-type strain grew well in an artificial seawater (ASW medium supplemented with nitrogen and phosphorus sources. The addition of HEPES buffer improved cell growth overall, although the growth in ASW medium was inferior to that in the synthetic BG-11 medium. The levels of proteins involved in sugar metabolism changed depending on the culture conditions. The biosynthesis of several amino acids including aspartate, glutamine, glycine, proline, ornithine, and lysine, was highly up-regulated by cultivation in ASW. Two types of natural seawater (NSW were also made available for the cultivation of Synechocystis cells, with supplementation of both nitrogen and phosphorus sources. These results revealed the potential use of seawater for the cultivation of freshwater cyanobacteria, which would help to reduce freshwater consumption during biorefinery using cyanobacteria.

Dissociation of the effects of epinephrine and insulin on glucose and protein metabolism

International Nuclear Information System (INIS)

Castellino, P.; Luzi, L.; Del Prato, S.; DeFronzo, R.A.

1990-01-01

The separate and combined effects of insulin and epinephrine on leucine metabolism were examined in healthy young volunteers. Subjects participated in four experimental protocols: (1) euglycemic insulin clamp (+80 microU/ml), (2) epinephrine infusion (50 ng.kg-1.min-1) plus somatostatin with basal replacement of insulin and glucagon, (3) combined epinephrine (50 ng.kg-1.min-1) plus insulin (+80 microU/ml) infusion, and (4) epinephrine and somatostatin as in study 2 plus basal amino acid replacement. Studies were performed with a prime-continuous infusion of [1-14C]leucine and indirect calorimetry. Our results indicate that (1) hyperinsulinemia causes a generalized decrease in plasma amino acid concentrations, including leucine; (2) the reduction in plasma leucine concentration is primarily due to an inhibition of endogenous leucine flux; nonoxidative leucine disposal decreases after insulin infusion; (3) epinephrine, without change in plasma insulin concentration, reduces plasma amino acid levels; (4) combined epinephrine-insulin infusion causes a greater decrease in plasma amino levels than observed with either hormone alone; this is because of a greater inhibition of endogenous leucine flux; and (5) when basal amino acid concentrations are maintained constant with a balanced amino acid infusion, epinephrine inhibits the endogenous leucine flux. In conclusion, the present results do not provide support for the concept that epinephrine is a catabolic hormone with respect to amino acid-protein metabolism. In contrast, epinephrine markedly inhibits insulin-mediated glucose metabolism

Key mediators of intracellular amino acids signaling to mTORC1 activation.

Science.gov (United States)

Duan, Yehui; Li, Fengna; Tan, Kunrong; Liu, Hongnan; Li, Yinghui; Liu, Yingying; Kong, Xiangfeng; Tang, Yulong; Wu, Guoyao; Yin, Yulong

2015-05-01

Mammalian target of rapamycin complex 1 (mTORC1) is activated by amino acids to promote cell growth via protein synthesis. Specifically, Ras-related guanosine triphosphatases (Rag GTPases) are activated by amino acids, and then translocate mTORC1 to the surface of late endosomes and lysosomes. Ras homolog enriched in brain (Rheb) resides on this surface and directly activates mTORC1. Apart from the presence of intracellular amino acids, Rag GTPases and Rheb, other mediators involved in intracellular amino acid signaling to mTORC1 activation include human vacuolar sorting protein-34 (hVps34) and mitogen-activating protein kinase kinase kinase kinase-3 (MAP4K3). Those molecular links between mTORC1 and its mediators form a complicate signaling network that controls cellular growth, proliferation, and metabolism. Moreover, it is speculated that amino acid signaling to mTORC1 may start from the lysosomal lumen. In this review, we discussed the function of these mediators in mTORC1 pathway and how these mediators are regulated by amino acids in details.

Effects of glucogenic and ketogenic feeding strategies on splanchnic glucose and amino acid metabolism in postpartum transition Holstein cows

DEFF Research Database (Denmark)

Larsen, Mogens; Kristensen, Niels Bastian

2012-01-01

assigned to 1 of 3 feeding strategies: a glucogenic diet (GLCG) based on sodium hydroxide treated wheat grain (56.5% of diet dry matter); a ketogenic diet (KETO) based on fodder beets (40.5% of diet dry matter); or an alfalfa-glucogenic strategy (ALF-GLCG) supplying 100% alfalfa (Medicago sativa L......Nine periparturient Holstein cows catheterized in major splanchnic vessels were used in a complete randomized design with repeated measurements to investigate effects of glucogenic and ketogenic feeding strategies on splanchnic metabolism of glucose and amino acids. At parturition, cows were.......) haylage at the day of parturition, followed by a 6-d linear shift to the GLCG diet. Samples were obtained 14 d before expected parturition as well as at 4, 15, and 29 d in milk (DIM). The net portal release of glucose was greatest with GLCG, reflecting the higher intake of ruminal escape starch with GLCG...

MetaFluxNet: the management of metabolic reaction information and quantitative metabolic flux analysis.

Science.gov (United States)

Lee, Dong-Yup; Yun, Hongsoek; Park, Sunwon; Lee, Sang Yup

2003-11-01

MetaFluxNet is a program package for managing information on the metabolic reaction network and for quantitatively analyzing metabolic fluxes in an interactive and customized way. It allows users to interpret and examine metabolic behavior in response to genetic and/or environmental modifications. As a result, quantitative in silico simulations of metabolic pathways can be carried out to understand the metabolic status and to design the metabolic engineering strategies. The main features of the program include a well-developed model construction environment, user-friendly interface for metabolic flux analysis (MFA), comparative MFA of strains having different genotypes under various environmental conditions, and automated pathway layout creation. http://mbel.kaist.ac.kr/ A manual for MetaFluxNet is available as PDF file.

A model of proteolysis and amino acid biosynthesis for Lactobacillus delbrueckii subsp. bulgaricus in whey.

Science.gov (United States)

Liu, Enuo; Zheng, Huajun; Hao, Pei; Konno, Tomonobu; Yu, Yao; Kume, Hisae; Oda, Munehiro; Ji, Zai-Si

2012-12-01

Lactobacillus delbrueckii subsp. bulgaricus 2038 (L. bulgaricus 2038) is a bacterium that is used as a starter for dairy products by Meiji Co., Ltd of Japan. Culturing L. bulgaricus 2038 with whey as the sole nitrogen source results in a shorter lag phase than other milk proteins under the same conditions (carbon source, minerals, and vitamins). Microarray results of gene expression revealed characteristics of amino acid anabolism with whey as the nitrogen source and established a model of proteolysis and amino acid biosynthesis for L. bulgaricus. Whey peptides and free amino acids are readily metabolized, enabling rapid entry into the logarithmic growth phase. The oligopeptide transport system is the primary pathway for obtaining amino acids. Amino acid biosynthesis maintains the balance between amino acids required for cell growth and the amount obtained from environment. The interconversion of amino acids is also important for L. bulgaricus 2038 growth.

A biotin enrichment strategy identifies novel carbonylated amino acids in proteins from human plasma

DEFF Research Database (Denmark)

Havelund, Jesper F; Wojdyla, Katarzyna; Davies, Michael J

2017-01-01

Protein carbonylation is an irreversible protein oxidation correlated with oxidative stress, various diseases and ageing. Here we describe a peptide-centric approach for identification and characterisation of up to 14 different types of carbonylated amino acids in proteins. The modified residues...... in vitro metal ion-catalysed oxidation. Furthermore, we assigned 133 carbonylated sites in 36 proteins in native human plasma protein samples. The optimised workflow enabled detection of 10 hitherto undetected types of carbonylated amino acids in proteins: aldehyde and ketone modifications of leucine...

Functional O-GlcNAc modifications: Implications in molecular regulation and pathophysiology

Science.gov (United States)

Wells, Lance

2016-01-01

O-linked β-N-acetylglucosamine (O-GlcNAc) is a regulatory post-translational modification of intracellular proteins. The dynamic and inducible cycling of the modification is governed by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) in response to UDP-GlcNAc levels in the hexosamine biosynthetic pathway (HBP). Due to its reliance on glucose flux and substrate availability, a major focus in the field has been on how O-GlcNAc contributes to metabolic disease. For years this post-translational modification has been known to modify thousands of proteins implicated in various disorders, but direct functional connections have until recently remained elusive. New research is beginning to reveal the specific mechanisms through which O-GlcNAc influences cell dynamics and disease pathology including clear examples of O-GlcNAc modification at a specific site on a given protein altering its biological functions. The following review intends to focus primarily on studies in the last half decade linking O-GlcNAc modification of proteins with chromatin-directed gene regulation, developmental processes, and several metabolically related disorders including Alzheimer’s, heart disease and cancer. These studies illustrate the emerging importance of this post-translational modification in biological processes and multiple pathophysiologies. PMID:24524620

A Novel Bifunctional Amino Acid Racemase With Multiple Substrate Specificity, MalY From Lactobacillus sakei LT-13: Genome-Based Identification and Enzymological Characterization

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Shiro Kato

2018-03-01

Full Text Available The Lactobacillus sakei strain LK-145 isolated from Moto, a starter of sake, produces potentially large amounts of three D-amino acids, D-Ala, D-Glu, and D-Asp, in a medium containing amylase-digested rice as a carbon source. The comparison of metabolic pathways deduced from the complete genome sequence of strain LK-145 to the type culture strain of Lactobacillus sakei strain LT-13 showed that the L- and D-amino acid metabolic pathways are similar between the two strains. However, a marked difference was observed in the putative cysteine/methionine metabolic pathways of strain LK-145 and LT-13. The cystathionine β-lyase homolog gene malY was annotated only in the genome of strain LT-13. Cystathionine β-lyase is an important enzyme in the cysteine/methionine metabolic pathway that catalyzes the conversion of L-cystathionine into L-homocysteine. In addition to malY, most genome-sequenced strains of L. sakei including LT-13 lacked the homologous genes encoding other putative enzymes in this pathway. Accordingly, the cysteine/methionine metabolic pathway likely does not function well in almost all strains of L. sakei. We succeeded in cloning and expressing the malY gene from strain LT-13 (Ls-malY in the cells of Escherichia coli BL21 (DE3 and characterized the enzymological properties of Ls-MalY. Spectral analysis of purified Ls-MalY showed that Ls-MalY contained a pyridoxal 5′-phosphate (PLP as a cofactor, and this observation agreed well with the prediction based on its primary structure. Ls-MalY showed amino acid racemase activity and cystathionine β-lyase activity. Ls-MalY showed amino acid racemase activities in various amino acids, such as Ala, Arg, Asn, Glu, Gln, His, Leu, Lys, Met, Ser, Thr, Trp, and Val. Mutational analysis revealed that the -amino group of Lys233 in the primary structure of Ls-MalY likely bound to PLP, and Lys233 was an essential residue for Ls-MalY to catalyze both the amino acid racemase and β-lyase reactions. In

Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics.

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Morgan N Price

2018-01-01

Full Text Available For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. We studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fill 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.

Targeted metabolomics analysis reveals the association between maternal folic acid supplementation and fatty acids and amino acids profiles in rat pups.

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Liu, Zhipeng; Liu, Rui; Chou, Jing; Yu, Jiaying; Liu, Xiaowei; Sun, Changhao; Li, Ying; Liu, Liyan

2018-07-15

Maternal diet during pregnancy can influence offspring's health by affecting development and metabolism. This study aimed to analyze the influence of maternal folic acid (FA) supplementation on the metabolism of rat pups using targeted metabolomics. Twenty female rats were randomly assigned to a FA supplementation (FAS group, n = 10) or control group (n = 10), which were fed AIN93G diet with 2 or 10 mg/kg FA, respectively. We then measured amino acids and their derivatives, biogenic amines, and fatty acids in the female rats and their pups by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC/MS-MS) and gas chromatography-mass spectrometry (GC/MS-MS). In maternal rats, the significant changes of three metabolites (proline, γ-aminobutyric acid and esterified octadecatetraenoic acid, P acids (leucine, isoleucine, serine, proline) were obtained in FAS pups. Furthermore, there were the decreased esterified fatty acids (arachidonic acid, eicosapentaenoic acid, and docosatetraenoic acid) and free fatty acids (oleic acid, linoleic acid, γ-linolenic acid, octadecatetraenoic acid, arachidonic acid, eicosapentaenoic acid and selacholeic acid) in FAS pups. Metabolic changes in the FAS pups were characterized by changes in fatty acids and amino acids. These results suggested that FA supplementation during pregnancy influenced amino acids and fatty acids metabolism in rat pups. This study provides new insights into the regulation of amino acids and fatty acids metabolism during early life. Copyright © 2018 Elsevier B.V. All rights reserved.

Unbiased plasma metabolomics reveal the correlation of metabolic pathways and Prakritis of humans.

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Shirolkar, Amey; Chakraborty, Sutapa; Mandal, Tusharkanti; Dabur, Rajesh

2017-11-25

Ayurveda, an ancient Indian medicinal system, has categorized human body constitutions in three broad constitutional types (prakritis) i.e. Vata, Pitta and Kapha. Analysis of plasma metabolites and related pathways to classify Prakriti specific dominant marker metabolites and metabolic pathways. 38 healthy male individuals were assessed for dominant Prakritis and their fasting blood samples were collected. The processed plasma samples were subjected to rapid resolution liquid chromatography-electrospray ionization-quadrupole time of flight mass spectrometry (RRLC-ESI-QTOFMS). Mass profiles were aligned and subjected to multivariate analysis. Partial least square discriminant analysis (PLS-DA) model showed 97.87% recognition capability. List of PLS-DA metabolites was subjected to permutative Benjamini-Hochberg false discovery rate (FDR) correction and final list of 76 metabolites with p  2.0 was identified. Pathway analysis using metascape and JEPETTO plugins in Cytoscape revealed that steroidal hormone biosynthesis, amino acid, and arachidonic acid metabolism are major pathways varying with different constitution. Biological Go processes analysis showed that aromatic amino acids, sphingolipids, and pyrimidine nucleotides metabolic processes were dominant in kapha type of body constitution. Fat soluble vitamins, cellular amino acid, and androgen biosynthesis process along with branched chain amino acid and glycerolipid catabolic processes were dominant in pitta type individuals. Vata Prakriti was found to have dominant catecholamine, arachidonic acid and hydrogen peroxide metabolomics processes. The neurotransmission and oxidative stress in vata, BCAA catabolic, androgen, xenobiotics metabolic processes in pitta, and aromatic amino acids, sphingolipid, and pyrimidine metabolic process in kaphaPrakriti were the dominant marker pathways. Copyright © 2017 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Published by Elsevier B.V. All rights

Genome-scale model of Streptococcus thermophilus LMG18311 for metabolic comparison.

NARCIS (Netherlands)

Pastink, M.I.; Teusink, B.; Hols, P.; Visser, S.; Vos, W.M.; Hugenholtz, J.

2009-01-01

In this report, we describe the amino acid metabolism and amino acid dependency of the dairy bacterium Streptococcus thermophilus LMG18311 and compare them with those of two other characterized lactic acid bacteria, Lactococcus lactis and Lactobacillus plantarum. Through the construction of a

A Sulfur Amino Acid–Free Meal Increases Plasma Lipids in Humans123

OpenAIRE

Park, Youngja; Le, Ngoc-Anh; Yu, Tianwei; Strobel, Fred; Gletsu-Miller, Nana; Accardi, Carolyn J.; Lee, Kichun S.; Wu, Shaoxiong; Ziegler, Thomas R.; Jones, Dean P.

2011-01-01

The content of sulfur amino acid (SAA) in a meal affects postprandial plasma cysteine concentrations and the redox potential of cysteine/cystine. Because such changes can affect enzyme, transporter, and receptor activities, meal content of SAA could have unrecognized effects on metabolism during the postprandial period. This pilot study used proton NMR (1H-NMR) spectroscopy of human plasma to test the hypothesis that dietary SAA content changes macronutrient metabolism. Healthy participants (...

The Complex Role of Branched Chain Amino Acids in Diabetes and Cancer

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Thomas M. O'Connell

2013-10-01

Full Text Available The obesity and diabetes epidemics are continuing to spread across the globe. There is increasing evidence that diabetes leads to a significantly higher risk for certain types of cancer. Both diabetes and cancer are characterized by severe metabolic perturbations and the branched chain amino acids (BCAAs appear to play a significant role in both of these diseases. These essential amino acids participate in a wide variety of metabolic pathways, but it is now recognized that they are also critical regulators of a number of cell signaling pathways. An elevation in branched chain amino acids has recently been shown to be significantly correlated with insulin resistance and the future development of diabetes. In cancer, the normal demands for BCAAs are complicated by the conflicting needs of the tumor and the host. The severe muscle wasting syndrome experience by many cancer patients, known as cachexia, has motivated the use of BCAA supplementation. The desired improvement in muscle mass must be balanced by the need to avoid providing materials for tumor proliferation. A better understanding of the complex functions of BCAAs could lead to their use as biomarkers of the progression of certain cancers in diabetic patients.

Amino Acid Signatures to Evaluate the Beneficial Effects of Weight Loss

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Nina Geidenstam

2017-01-01

Full Text Available Aims. We investigated the relationship between circulating amino acid levels and obesity; to what extent weight loss followed by weight maintenance can correct amino acid abnormalities; and whether amino acids are related to weight loss. Methods. Amino acids associated with waist circumference (WC and BMI were studied in 804 participants from the Malmö Diet and Cancer Cardiovascular Cohort (MDC-CC. Changes in amino acid levels were analyzed after weight loss and weight maintenance in 12 obese subjects and evaluated in a replication cohort (n=83. Results. Out of the eight identified BMI-associated amino acids from the MDC-CC, alanine, isoleucine, tyrosine, phenylalanine, and glutamate decreased after weight loss, while asparagine increased after weight maintenance. These changes were validated in the replication cohort. Scores that were constructed based on obesity-associated amino acids and known risk factors decreased in the ≥10% weight loss group with an associated change in BMI (R2=0.16–0.22, p<0.002, whereas the scores increased in the <10% weight loss group (p<0.0004. Conclusions. Weight loss followed by weight maintenance leads to differential changes in amino acid levels associated with obesity. Treatment modifiable scores based on epidemiological and interventional data may be used to evaluate the potential metabolic benefit of weight loss.

Branched-chain amino acid supplementation promotes aerobic growth of Salmonella Typhimurium under nitrosative stress conditions.

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Park, Yoon Mee; Lee, Hwa Jeong; Jeong, Jae-Ho; Kook, Joong-Ki; Choy, Hyon E; Hahn, Tae-Wook; Bang, Iel Soo

2015-12-01

Nitric oxide (NO) inactivates iron-sulfur enzymes in bacterial amino acid biosynthetic pathways, causing amino acid auxotrophy. We demonstrate that exogenous supplementation with branched-chain amino acids (BCAA) can restore the NO resistance of hmp mutant Salmonella Typhimurium lacking principal NO-metabolizing enzyme flavohemoglobin, and of mutants further lacking iron-sulfur enzymes dihydroxy-acid dehydratase (IlvD) and isopropylmalate isomerase (LeuCD) that are essential for BCAA biosynthesis, in an oxygen-dependent manner. BCAA supplementation did not affect the NO consumption rate of S. Typhimurium, suggesting the BCAA-promoted NO resistance independent of NO metabolism. BCAA supplementation also induced intracellular survival of ilvD and leuCD mutants at wild-type levels inside RAW 264.7 macrophages that produce constant amounts of NO regardless of varied supplemental BCAA concentrations. Our results suggest that the NO-induced BCAA auxotrophy of Salmonella, due to inactivation of iron-sulfur enzymes for BCAA biosynthesis, could be rescued by bacterial taking up exogenous BCAA available in oxic environments.

Reprogramming amino acid catabolism in CHO cells with CRISPR-Cas9 genome editing improves cell growth and reduces by-product secretion

DEFF Research Database (Denmark)

Ley, Daniel; Pereira, Sara; Pedersen, Lasse Ebdrup

2017-01-01

CHO cells primarily utilize amino acids for three processes: biomass synthesis, recombinant protein production and catabolism. In this work, we disrupted 9 amino acid catabolic genes participating in 7 dierent catabolic pathways, to increase synthesis of biomass and recombinant protein, while red...... reducing production of growth-inhibiting metabolic by-products from amino acid catabolism....

Functionalized 2′-amino-α-L-LNA

DEFF Research Database (Denmark)

Kumar, T. Santhosh; Madsen, Andreas Stahl; Østergaard, Michael

2009-01-01

Chemically modified oligonucleotides are increasingly applied in nucleic acid based therapeutics and diagnostics. LNA (locked nucleic acid) and its diastereomer α-L-LNA are two promising examples thereof that exhibit increased thermal and enzymatic stability. Herein, the synthesis, biophysical......′-functionalities such as 2′-N-acetyl-2′-amino-α-L-LNA (monomer V) had detrimental effects on thermal affinity toward DNA/RNA complements with decreases of as much as -16.5 °C per modification. Extensive thermal DNA selectivity, favorable entropic contributions upon duplex formation, hybridization...

FREE AMINO ACID COMPOSITION IN SCOTS PINE TISSUES UNDER STRESS IMPACT IN RHIZOSPHERE

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Sudachkova N.E.

2007-12-01

Full Text Available The free amino acid content in the needles and the inner bark of stems and roots of 8-13-ages self-sawn trees of Pinus sylvestris L. in Central Siberia in experimental and natural conditions was compared. The experiments imitated an influence of long-seasonal or permafrost, soil drought and root hypoxia, concomitant flooding. The aim of the investigation was to expose the adaptive changes of these metabolites composition under stress impact. All of types of stress influences changed the total free amino acid content in the tissues of different morphological tree parts: the cooling of root system caused a deposit of free amino acids in overground tree part, the water deficit stimulated an accumulation of free amino acids in root inner bark, the flooding decreased the amino acid content in all tissues. The ratio in a group of amino acids with glutamic acid as metabolic precursor (-aminobutyric (GABA, proline, arginine, citrulline and ornithine changed under different stress impact. The cold stress in rhizosphere caused GABA accumulation in the needles and stem but not in the roots in the period of soil thawing. The moderate moisture deficit had not an influence on GABA content, the flooding caused GABA accumulation only in new needles. The maximal exceeding above control were marked for the sum of arginine and its metabolic precursors citrulline and ornithine. The group of these compounds may be considered as stress metabolites for scots pine, but specificity of depositing of these amino acids at water stress requires additional proofs. Since the proline accumulation was showed in separate times in the different tissues under all of investigated stressors impact, the specificity of proline as indicator of water stress in scots pine tissues is debatable. The disturbance of donor-acceptor connections in experiment with cooling resulted to the amino acid accumulation in stem inner bark, in experiment with drought – in root inner bark.

Cancer Metabolism: A Modeling Perspective

DEFF Research Database (Denmark)

Ghaffari, Pouyan; Mardinoglu, Adil; Nielsen, Jens

2015-01-01

suggest that utilization of amino acids and lipids contributes significantly to cancer cell metabolism. Also recent progresses in our understanding of carcinogenesis have revealed that cancer is a complex disease and cannot be understood through simple investigation of genetic mutations of cancerous cells...

Molecular Basis of Prodrug Activation by Human Valacyclovirase, an [alpha]-Amino Acid Ester Hydrolase

Energy Technology Data Exchange (ETDEWEB)

Lai, Longsheng; Xu, Zhaohui; Zhou, Jiahai; Lee, Kyung-Dall; Amidon, Gordon L. (Michigan)

2008-07-08

Chemical modification to improve biopharmaceutical properties, especially oral absorption and bioavailability, is a common strategy employed by pharmaceutical chemists. The approach often employs a simple structural modification and utilizes ubiquitous endogenous esterases as activation enzymes, although such enzymes are often unidentified. This report describes the crystal structure and specificity of a novel activating enzyme for valacyclovir and valganciclovir. Our structural insights show that human valacyclovirase has a unique binding mode and specificity for amino acid esters. Biochemical data demonstrate that the enzyme hydrolyzes esters of {alpha}-amino acids exclusively and displays a broad specificity spectrum for the aminoacyl moiety similar to tricorn-interacting aminopeptidase F1. Crystal structures of the enzyme, two mechanistic mutants, and a complex with a product analogue, when combined with biochemical analysis, reveal the key determinants for substrate recognition; that is, a flexible and mostly hydrophobic acyl pocket, a localized negative electrostatic potential, a large open leaving group-accommodating groove, and a pivotal acidic residue, Asp-123, after the nucleophile Ser-122. This is the first time that a residue immediately after the nucleophile has been found to have its side chain directed into the substrate binding pocket and play an essential role in substrate discrimination in serine hydrolases. These results as well as a phylogenetic analysis establish that the enzyme functions as a specific {alpha}-amino acid ester hydrolase. Valacyclovirase is a valuable target for amino acid ester prodrug-based oral drug delivery enhancement strategies.

Evolutionary systems biology of amino acid biosynthetic cost in yeast.

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Michael D Barton

2010-08-01

Full Text Available Every protein has a biosynthetic cost to the cell based on the synthesis of its constituent amino acids. In order to optimise growth and reproduction, natural selection is expected, where possible, to favour the use of proteins whose constituents are cheaper to produce, as reduced biosynthetic cost may confer a fitness advantage to the organism. Quantifying the cost of amino acid biosynthesis presents challenges, since energetic requirements may change across different cellular and environmental conditions. We developed a systems biology approach to estimate the cost of amino acid synthesis based on genome-scale metabolic models and investigated the effects of the cost of amino acid synthesis on Saccharomyces cerevisiae gene expression and protein evolution. First, we used our two new and six previously reported measures of amino acid cost in conjunction with codon usage bias, tRNA gene number and atomic composition to identify which of these factors best predict transcript and protein levels. Second, we compared amino acid cost with rates of amino acid substitution across four species in the genus Saccharomyces. Regardless of which cost measure is used, amino acid biosynthetic cost is weakly associated with transcript and protein levels. In contrast, we find that biosynthetic cost and amino acid substitution rates show a negative correlation, but for only a subset of cost measures. In the economy of the yeast cell, we find that the cost of amino acid synthesis plays a limited role in shaping transcript and protein expression levels compared to that of translational optimisation. Biosynthetic cost does, however, appear to affect rates of amino acid evolution in Saccharomyces, suggesting that expensive amino acids may only be used when they have specific structural or functional roles in protein sequences. However, as there appears to be no single currency to compute the cost of amino acid synthesis across all cellular and environmental

Amino acids and autophagy: cross-talk and co-operation to control cellular homeostasis.

Science.gov (United States)

Carroll, Bernadette; Korolchuk, Viktor I; Sarkar, Sovan

2015-10-01

Maintenance of amino acid homeostasis is important for healthy cellular function, metabolism and growth. Intracellular amino acid concentrations are dynamic; the high demand for protein synthesis must be met with constant dietary intake, followed by cellular influx, utilization and recycling of nutrients. Autophagy is a catabolic process via which superfluous or damaged proteins and organelles are delivered to the lysosome and degraded to release free amino acids into the cytoplasm. Furthermore, autophagy is specifically activated in response to amino acid starvation via two key signaling cascades: the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) and the general control nonderepressible 2 (GCN2) pathways. These pathways are key regulators of the integration between anabolic (amino acid depleting) and catabolic (such as autophagy which is amino acid replenishing) processes to ensure intracellular amino acid homeostasis. Here, we discuss the key roles that amino acids, along with energy (ATP, glucose) and oxygen, are playing in cellular growth and proliferation. We further explore how sophisticated methods are employed by cells to sense intracellular amino acid concentrations, how amino acids can act as a switch to dictate the temporal and spatial activation of anabolic and catabolic processes and how autophagy contributes to the replenishment of free amino acids, all to ensure cell survival. Relevance of these molecular processes to cellular and organismal physiology and pathology is also discussed.

Alterations in protein and amino acid metabolism in rats fed a branched-chain amino acid- or leucine-enriched diet during postprandial and postabsorptive states.

Science.gov (United States)

Holecek, Milan; Siman, Pavel; Vodenicarovova, Melita; Kandar, Roman

2016-01-01

Many people believe in favourable effects of branched-chain amino acids (BCAAs; valine, leucine, and isoleucine), especially leucine, on muscle protein balance and consume BCAAs for many years. We determined the effects of the chronic intake of a BCAA- or leucine-enriched diet on protein and amino acid metabolism in fed and postabsorptive states. Rats were fed a standard diet, a diet with a high content of valine, leucine, and isoleucine (HVLID), or a high content of leucine (HLD) for 2 months. Half of the animals in each group were sacrificed in the fed state on the last day, and the other half were sacrificed after overnight fast. Protein synthesis was assessed using the flooding dose method (L-[3,4,5-(3)H]phenylalanine), proteolysis on the basis of chymotrypsin-like activity (CHTLA) of proteasome and cathepsin B and L activities. Chronic intake of HVLID or HLD enhanced plasma levels of urea, alanine and glutamine. HVLID also increased levels of all three BCAA and branched-chain keto acids (BCKA), HLD increased leucine, ketoisocaproate and alanine aminotransferase and decreased valine, ketovaline, isoleucine, ketoisoleucine, and LDL cholesterol. Tissue weight and protein content were lower in extensor digitorum longus muscles in the HLD group and higher in kidneys in the HVLID and HLD groups. Muscle protein synthesis in postprandial state was higher in the HVLID group, and CHTLA was lower in muscles of the HVLID and HLD groups compared to controls. Overnight starvation enhanced alanine aminotransferase activity in muscles, and decreased protein synthesis in gastrocnemius (in HVLID group) and extensor digitorum longus (in HLD group) muscles more than in controls. Effect of HVLID and HLD on CHTLA in muscles in postabsorptive state was insignificant. The results failed to demonstrate positive effects of the chronic consumption of a BCAA-enriched diet on protein balance in skeletal muscle and indicate rather negative effects from a leucine-enriched diet. The primary

Amino acid metabolism in dairy cows and their regulation in milk synthesis.

Science.gov (United States)

Wang, Feiran; Shi, Haitao; Wang, Shuxiang; Wang, Yajing; Cao, Zhijun; Li, Shengli

2018-06-10

Reducing dietary crude protein (CP) and supplementing with certain amino acids (AAs) has been known as a potential solution to improve nitrogen (N) efficiency in dairy production. Thus understanding how AAs are utilized in various sites along the gut is critical. AA flow from the intestine to portal-drained viscera (PDV) and liver then to the mammary gland was elaborated in this article. Recoveries in individual AA in PDV and liver seem to share similar AA pattern with input: output ratio in mammary gland, which subdivides essential AA (EAA) into two groups, lysine (Lys) and branched-chain AA (BCAA) in group 1, input: output ratio > 1; methionine (Met), histidine (His), phenylalanine (Phe) etc. in group 2, input: output ratio close to 1. AAs in the mammary gland are either utilized for milk protein synthesis or retained as body tissue, or catabolized. The fractional removal of AAs and the number and activity of AA transporters together contribute to the ability of AAs going through mammary cells. Mammalian target of rapamycin (mTOR) pathway is closely related to milk protein synthesis and provides alternatives for AA regulation of milk protein synthesis, which connects AA with lactose synthesis via α-lactalbumin (gene: LALBA) and links with milk fat synthesis via sterol regulatory element-binding transcription protein 1 (SREBP1) and peroxisome proliferator-activated receptor (PPAR). Overall, AA flow across various tissues reveal AA metabolism and utilization in dairy cows on one hand. While the function of AA in the biosynthesis of milk protein, fat and lactose at both transcriptional and posttranscriptional level from another angle provides the possibility for us to regulate them for higher efficiency. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Branched-Chain Amino Acids.

Science.gov (United States)

Yamamoto, Keisuke; Tsuchisaka, Atsunari; Yukawa, Hideaki

Branched-chain amino acids (BCAAs), viz., L-isoleucine, L-leucine, and L-valine, are essential amino acids that cannot be synthesized in higher organisms and are important nutrition for humans as well as livestock. They are also valued as synthetic intermediates for pharmaceuticals. Therefore, the demand for BCAAs in the feed and pharmaceutical industries is increasing continuously. Traditional industrial fermentative production of BCAAs was performed using microorganisms isolated by random mutagenesis. A collection of these classical strains was also scientifically useful to clarify the details of the BCAA biosynthetic pathways, which are tightly regulated by feedback inhibition and transcriptional attenuation. Based on this understanding of the metabolism of BCAAs, it is now possible for us to pursue strains with higher BCAA productivity using rational design and advanced molecular biology techniques. Additionally, systems biology approaches using augmented omics information help us to optimize carbon flux toward BCAA production. Here, we describe the biosynthetic pathways of BCAAs and their regulation and then overview the microorganisms developed for BCAA production. Other chemicals, including isobutanol, i.e., a second-generation biofuel, can be synthesized by branching the BCAA biosynthetic pathways, which are also outlined.

Epigenetic Modifications and Diabetic Retinopathy

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Renu A. Kowluru

2013-01-01

Full Text Available Diabetic retinopathy remains one of the most debilitating chronic complications, but despite extensive research in the field, the exact mechanism(s responsible for how retina is damaged in diabetes remains ambiguous. Many metabolic pathways have been implicated in its development, and genes associated with these pathways are altered. Diabetic environment also facilitates epigenetics modifications, which can alter the gene expression without permanent changes in DNA sequence. The role of epigenetics in diabetic retinopathy is now an emerging area, and recent work has shown that genes encoding mitochondrial superoxide dismutase (Sod2 and matrix metalloproteinase-9 (MMP-9 are epigenetically modified, activates of epigenetic modification enzymes, histone lysine demethylase 1 (LSD1, and DNA methyltransferase are increased, and the micro RNAs responsible for regulating nuclear transcriptional factor and VEGF are upregulated. With the growing evidence of epigenetic modifications in diabetic retinopathy, better understanding of these modifications has potential to identify novel targets to inhibit this devastating disease. Fortunately, the inhibitors and mimics targeted towards histone modification, DNA methylation, and miRNAs are now being tried for cancer and other chronic diseases, and better understanding of the role of epigenetics in diabetic retinopathy will open the door for their possible use in combating this blinding disease.

Exceptional longevity and exceptionally high metabolic rates in anthropoid primates are linked to a major modification of the ubiquinone reduction site of cytochrome b.

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Rottenberg, Hagai

2014-10-01

The maximal lifespan of Anthropoid primates (monkeys, apes and humans) exceed the lifespan of most other mammals of equal body mass. Unexpectedly, their exceptional longevity is associated with exceptionally high metabolic rates, in apparent contradiction to the Free Radical Theory of Aging. It was therefore suggested that in anthropoid primates (and several other taxa of mammals and birds) the mitochondrial electron transport complexes evolved to modify the relationship between basal electron transport and superoxide generation to allow for the evolution of exceptional longevity. Cytochrome b, the core protein of the bc1 complex is a major source of superoxide. The amino-acid sequence of cytochrome b evolved much faster in anthropoid than in prosimian primates, and most other mammals, resulting in a large change in the amino-acids composition of the protein. As a result of these changes cytochrome b in anthropoid primates is significantly less hydrophobic and contains more polar residues than other primates and most other mammals. Most of these changes are clustered around the reduction site of uboiquinone. In particular a key positively charged residue, arginine 313, that interacts with propionate D of heme bH, and thus raises its redox potential, is substituted in anthropoid primates with the neutral residue glutamine, most likely resulting in a lower redox potential of heme bH and faster reduction of ubiquinone at high proton motive force. It is suggested that these changes contribute to the observed increased rates of basal metabolism and reduce the rates of superoxide production, thus allowing for increased lifespan.

Rapid quantification of underivatized amino acids in plasma by hydrophilic interaction liquid chromatography (HILIC) coupled with tandem mass-spectrometry

NARCIS (Netherlands)

Prinsen, Hubertus C M T; Schiebergen-Bronkhorst, B. G M; Roeleveld, M. W.; Jans, J. J M; de Sain-van der Velden, M. G M; Visser, G.; van Hasselt, P. M.; Verhoeven-Duif, N. M.

Background: Amino acidopathies are a class of inborn errors of metabolism (IEM) that can be diagnosed by analysis of amino acids (AA) in plasma. Current strategies for AA analysis include cation exchange HPLC with post-column ninhydrin derivatization, GC-MS, and LC-MS/MS-related methods. Major

Characterization of GdFFD, a d-Amino Acid-containing Neuropeptide That Functions as an Extrinsic Modulator of the Aplysia Feeding Circuit*

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Bai, Lu; Livnat, Itamar; Romanova, Elena V.; Alexeeva, Vera; Yau, Peter M.; Vilim, Ferdinand S.; Weiss, Klaudiusz R.; Jing, Jian; Sweedler, Jonathan V.

2013-01-01

During eukaryotic translation, peptides/proteins are created using l-amino acids. However, a d-amino acid-containing peptide (DAACP) can be produced through post-translational modification via an isomerase enzyme. General approaches to identify novel DAACPs and investigate their function, particularly in specific neural circuits, are lacking. This is primarily due to the difficulty in characterizing this modification and due to the limited information on neural circuits in most species. We describe a multipronged approach to overcome these limitations using the sea slug Aplysia californica. Based on bioinformatics and homology to known DAACPs in the land snail Achatina fulica, we targeted two predicted peptides in Aplysia, GFFD, similar to achatin-I (GdFAD versus GFAD, where dF stands for d-phenylalanine), and YAEFLa, identical to fulyal (YdAEFLa versus YAEFLa), using stereoselective analytical methods, i.e. MALDI MS fragmentation analysis and LC-MS/MS. Although YAEFLa in Aplysia was detected only in an all l-form, we found that both GFFD and GdFFD were present in the Aplysia CNS. In situ hybridization and immunolabeling of GFFD/GdFFD-positive neurons and fibers suggested that GFFD/GdFFD might act as an extrinsic modulator of the feeding circuit. Consistent with this hypothesis, we found that GdFFD induced robust activity in the feeding circuit and elicited egestive motor patterns. In contrast, the peptide consisting of all l-amino acids, GFFD, was not bioactive. Our data indicate that the modification of an l-amino acid-containing neuropeptide to a DAACP is essential for peptide bioactivity in a motor circuit, and thus it provides a functional significance to this modification. PMID:24078634

Eco-physiological studies on Indian arid zone plants. VI. Effect of sodium chloride and abscisic acid on amino-acid and protein metabolism in leaves of Phaseolus aconitifolius

Energy Technology Data Exchange (ETDEWEB)

Huber, W.; Kreutmeier, F.; Sankhla, N.

1977-01-01

The effect of sodium chloride (NaCl) and abscisic acid (ABA) on protein synthesis, protein hydrolysis, activities of alanine and aspartate aminotransferases, glutamate dehydrogenase, glutamine synthetase, ..delta..-pyrroline-5-carboxylate-reductase and amino-acid composition was investigated in the leaves of four days old Phaseolus aconitifolius seedlings. Both NaCl and ABA inhibited protein synthesis, but promoted the activities of leucine arylamidase, alanine and aspartate aminotransferases, glutamate dehydrogenase, glutamine synthetase and ..delta..-pyrroline-5-carboxylate-reductase. The results of the amino-acid analysis indicated following treatment with NaCl the amounts of proline, arginine, serine and glutamic acid increased significantly in the leaves. An increase of the proline concentration could be observed only up to a salt concentration of 8.5 x 10/sup -3/ M. Increasing concentrations of ABA also brought a corresponding rise in proline, serine and glutamic acid content. Interestingly the decrease of proline concentration by a salt concentration of more than 8.5 x 10/sup -3/ M is correlated with a decrease in endogenous ABA-content. The possible significance of the similarites between the action of abscisic acid and salinity in influencing the amino-acid and protein metabolism in Phaseolus aconitifolius seedlings during stress is discussed. 31 references, 8 figures, 2 tables.

Effects of 1,2-cyclohexanedione modification on the metabolism of very low density lipoprotein apolipoprotein B: potential role of receptors in intermediate density lipoprotein catabolism

International Nuclear Information System (INIS)

Packard, C.J.; Boag, D.E.; Clegg, R.; Bedford, D.; Shepherd, J.

1985-01-01

The conversion of very low density (VLDL) to low density lipoproteins (LDL) is a two-step process. The first step is mediated by lipoprotein lipase, but the mechanism responsible for the second is obscure. In this study we examined the possible involvement of receptors at this stage. Apolipoprotein B (apoB)-containing lipoproteins were separated into three fractions, VLDL (Sf 100-400), an intermediate fraction IDL (Sf 12-100), and LDL (Sf 0-12). Autologous 125I-labeled VLDL and 131I-labeled 1,2-cyclohexanedione-modified VLDL were injected into the plasma of four normal subjects and the rate of transfer of apoB radioactivity was followed through IDL to LDL. Modification did not affect VLDL to IDL conversion. Thereafter, however, the catabolism of modified apoB in IDL was retarded and its appearance in LDL was delayed. Hence, functional arginine residues (and by implication, receptors) are required in this process. Confirmation of this was obtained by injecting 125I-labeled IDL and 131I-labeled cyclohexanedione-treated IDL into two additional subjects. Again, IDL metabolism was delayed by approximately 50% as a result of the modification. These data are consistent with the view that receptors are involved in the metabolism of intermediate density lipoprotein

Self-management for obesity and cardio-metabolic fitness: Description and evaluation of the lifestyle modification program of a randomised controlled trial