Treatment of Creatine Transporter (SLC6A8) Deficiency With Oral S-Adenosyl Methionine as Adjunct to L-arginine, Glycine, and Creatine Supplements.

Science.gov (United States)

Jaggumantri, Sravan; Dunbar, Mary; Edgar, Vanessa; Mignone, Cristina; Newlove, Theresa; Elango, Rajavel; Collet, Jean Paul; Sargent, Michael; Stockler-Ipsiroglu, Sylvia; van Karnebeek, Clara D M

2015-10-01

Creatine transporter (SLC6A8) deficiency is an X-linked inborn error of metabolism characterized by cerebral creatine deficiency, behavioral problems, seizures, hypotonia, and intellectual developmental disability. A third of patients are amenable to treatment with high-dose oral creatine, glycine, and L-arginine supplementation. Given the limited treatment response, we initiated an open-label observational study to evaluate the effect of adjunct S-adenosyl methionine to further enhance intracerebral creatine synthesis. Significant and reproducible issues with sleep and behavior were noted in both male patients on a dose of 50/mg/kg. One of the two patients stopped S-adenosyl methionine and did not come for any follow-up. A safe and tolerable dose (17 mg/kg/day) was identified in the other patient. On magnetic resonance spectroscopy, this 8-year-old male did not show an increase in intracerebral creatine. However, significant improvement in speech/language skills, muscle mass were observed as well as in personal outcomes as defined by the family in activities related to communication and decision making. Further research is needed to assess the potential of S-adenosyl methionine as an adjunctive therapy for creatine transporter deficiency patients and to define the optimal dose. Our study also illustrates the importance of pathophysiology-based treatment, individualized outcome assessment, and patient/family participation in rare diseases research. Copyright © 2015 Elsevier Inc. All rights reserved.

4-Demethylwyosine Synthase from Pyrococcus abyssi Is a Radical-S-adenosyl-l-methionine Enzyme with an Additional [4Fe-4S]+2 Cluster That Interacts with the Pyruvate Co-substrate*

Science.gov (United States)

Perche-Letuvée, Phanélie; Kathirvelu, Velavan; Berggren, Gustav; Clemancey, Martin; Latour, Jean-Marc; Maurel, Vincent; Douki, Thierry; Armengaud, Jean; Mulliez, Etienne; Fontecave, Marc; Garcia-Serres, Ricardo; Gambarelli, Serge; Atta, Mohamed

2012-01-01

Wybutosine and its derivatives are found in position 37 of tRNA encoding Phe in eukaryotes and archaea. They are believed to play a key role in the decoding function of the ribosome. The second step in the biosynthesis of wybutosine is catalyzed by TYW1 protein, which is a member of the well established class of metalloenzymes called “Radical-SAM.” These enzymes use a [4Fe-4S] cluster, chelated by three cysteines in a CX3CX2C motif, and S-adenosyl-l-methionine (SAM) to generate a 5′-deoxyadenosyl radical that initiates various chemically challenging reactions. Sequence analysis of TYW1 proteins revealed, in the N-terminal half of the enzyme beside the Radical-SAM cysteine triad, an additional highly conserved cysteine motif. In this study we show by combining analytical and spectroscopic methods including UV-visible absorption, Mössbauer, EPR, and HYSCORE spectroscopies that these additional cysteines are involved in the coordination of a second [4Fe-4S] cluster displaying a free coordination site that interacts with pyruvate, the second substrate of the reaction. The presence of two distinct iron-sulfur clusters on TYW1 is reminiscent of MiaB, another tRNA-modifying metalloenzyme whose active form was shown to bind two iron-sulfur clusters. A possible role for the second [4Fe-4S] cluster in the enzyme activity is discussed. PMID:23043105

Levels of Key Enzymes of Methionine-Homocysteine Metabolism in Preeclampsia

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Alejandra Pérez-Sepúlveda

2013-01-01

Full Text Available Objective. To evaluate the role of key enzymes in the methionine-homocysteine metabolism (MHM in the physiopathology of preeclampsia (PE. Methods. Plasma and placenta from pregnant women (32 controls and 16 PE patients were analyzed after informed consent. Protein was quantified by western blot. RNA was obtained with RNA purification kit and was quantified by reverse transcritase followed by real-time PCR (RT-qPCR. Identification of the C677T and A1298C methylenetetrahydrofolate reductase (MTHFR single-nucleotide polymorphisms (SNPs and A2756G methionine synthase (MTR SNP was performed using PCR followed by a high-resolution melting (HRM analysis. S-adenosyl methionine (SAM and S-adenosyl homocysteine (SAH were measured in plasma using high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS. The SNP association analysis was carried out using Fisher’s exact test. Statistical analysis was performed using a Mann-Whitney test. Results. RNA expression of MTHFR and MTR was significantly higher in patients with PE as compared with controls. Protein, SAM, and SAH levels showed no significant difference between preeclamptic patients and controls. No statistical differences between controls and PE patients were observed with the different SNPs studied. Conclusion. The RNA expression of MTHFR and MTR is elevated in placentas of PE patients, highlighting a potential compensation mechanism of the methionine-homocysteine metabolism in the physiopathology of this disease.

S-adenosyl-L-(l-14C)-homocysteine

International Nuclear Information System (INIS)

Thomas, H.J.; Montgomery, J.A.

1987-01-01

S-Adenosyl-L-(1- 14 C)-homocysteine was prepared from commercially available L-(1- 14 C)-methionine by conversion first to S-benzyl-L-(1- 14 C)-homocysteine which upon treatment with sodium in liquid ammonia gave the disodium salt of L-(1- 14 C)-homocysteine. Reaction of this sodium salt with 5'-O-tosyladenosine gave the title compound. (author)

A coupled photometric assay for characterization of S-adenosyl-l-homocysteine hydrolases in the physiological hydrolytic direction.

Science.gov (United States)

Kailing, Lyn L; Bertinetti, Daniela; Herberg, Friedrich W; Pavlidis, Ioannis V

2017-10-25

S-Adenosyl-l-homocysteine hydrolases (SAHases) are important metabolic enzymes and their dysregulation is associated with some severe diseases. In vivo they catalyze the hydrolysis of S-adenosyl-l-homocysteine (SAH), the by-product of methylation reactions in various organisms. SAH is a potent inhibitor of methyltransferases, thus its removal from the equilibrium is an important requirement for methylation reactions. SAH hydrolysis is also the first step in the cellular regeneration process of the methyl donor S-adenosyl-l-methionine (SAM). However, in vitro the equilibrium lies towards the synthetic direction. To enable characterization of SAHases in the physiologically relevant direction, we have developed a coupled photometric assay that shifts the equilibrium towards hydrolysis by removing the product adenosine, using a high affinity adenosine kinase (AK). This converts adenosine to AMP and thereby forms equimolar amounts of ADP, which is phosphorylated by a pyruvate kinase (PK), in turn releasing pyruvate. The readout of the assay is the consumption of NADH during the lactate dehydrogenase (LDH) catalyzed reduction of pyruvate to lactic acid. The applicability of the assay is showcased for the determination of the kinetic constants of an SAHase from Bradyrhizobium elkanii (K M,SAH 41±5μM, v max,SAH 25±1μM/min with 0.13mg/mL enzyme). This assay is a valuable tool for in vitro characterization of SAHases with biotechnological potential, and for monitoring SAHase activity in diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

Isolation and characterization of a gene encoding a S-adenosyl-l-methionine-dependent halide/thiol methyltransferase (HTMT) from the marine diatom Phaeodactylum tricornutum: Biogenic mechanism of CH(3)I emissions in oceans.

Science.gov (United States)

Toda, Hiroshi; Itoh, Nobuya

2011-04-01

Several marine algae including diatoms exhibit S-adenosyl-l-methionine (SAM) halide/thiol methyltransferase (HTMT) activity, which is involved in the emission of methyl halides. In this study, the in vivo biogenic emission of methyl iodide from the diatom Phaeodactylum tricornutum was found to be clearly correlated with iodide concentration in the incubation media. The gene encoding HTMT (Pthtmt) was isolated from P. tricornutum CCAP 1055/1, and expressed in Escherichia coli. The molecular weight of the enzyme was 29.7kDa including a histidine tag, and the optimal pH was around pH 7.0. The kinetic properties of recombinant PtHTMT towards Cl(-), Br(-), I(-), [SH](-), [SCN](-), and SAM were 637.88mM, 72.83mM, 8.60mM, 9.92mM, 7.9mM, and 0.016mM, respectively, and were similar to those of higher-plant HTMTs, except that the activity towards thiocyanate was lower. The biogenic emission of methyl halides from the cultured cells and the enzymatic properties of HTMT suggest that the HMT/HTMT reaction is key to understanding the biogenesis of methyl halides in oceanic environments as well as terrestrial ones. Copyright © 2010 Elsevier Ltd. All rights reserved.

S-Adenosyl-L-methionine protects the probiotic yeast, Saccharomyces boulardii, from acid-induced cell death.

Science.gov (United States)

Cascio, Vincent; Gittings, Daniel; Merloni, Kristen; Hurton, Matthew; Laprade, David; Austriaco, Nicanor

2013-02-13

Saccharomyces boulardii is a probiotic yeast routinely used to prevent and to treat gastrointestinal disorders, including the antibiotic-associated diarrhea caused by Clostridium difficile infections. However, only 1-3% of the yeast administered orally is recovered alive in the feces suggesting that this yeast is unable to survive the acidic environment of the gastrointestinal tract. We provide evidence that suggests that S. boulardii undergoes programmed cell death (PCD) in acidic environments, which is accompanied by the generation of reactive oxygen species and the appearance of caspase-like activity. To better understand the mechanism of cell death at the molecular level, we generated microarray gene expression profiles of S. boulardii cells cultured in an acidic environment. Significantly, functional annotation revealed that the up-regulated genes were significantly over-represented in cell death pathways Finally, we show that S-adenosyl-L-methionine (AdoMet), a commercially available, FDA-approved dietary supplement, enhances the viability of S. boulardii in acidic environments, most likely by preventing programmed cell death. In toto, given the observation that many of the proven health benefits of S. boulardii are dependent on cell viability, our data suggests that taking S. boulardii and AdoMet together may be a more effective treatment for gastrointestinal disorders than taking the probiotic yeast alone.

A comprehensive review on the efficacy of S-Adenosyl-L-methionine in Major Depressive Disorder.

Science.gov (United States)

De Berardis, Domenico; Orsolini, Laura; Serroni, Nicola; Girinelli, Gabriella; Iasevoli, Felice; Tomasetti, Carmine; de Bartolomeis, Andrea; Mazza, Monica; Valchera, Alessandro; Fornaro, Michele; Perna, Giampaolo; Piersanti, Monica; Di Nicola, Marco; Cavuto, Marilde; Martinotti, Giovanni; Di Giannantonio, Massimo

2016-01-01

To review the antidepressant efficacy of S-Adenosyl-L-Methionine (SAMe) both in monotherapy and/or in augmentation with antidepressants to better understand its potential role in the treatment of patients with Major Depressive Disorder (MDD) and Treatment-Resistant Depression (TRD). A MEDLINE/PubMed search was carried out by using the following set of keywords: ((SAMe OR SAdenosyl- L-Methionine) AND (major depressive disorder OR depression)). Data Selection and Data Extraction: No language or time restrictions were placed on the electronic searches. Randomized controlled trials and open trials involving humans were here included and analyzed. The references of published articles identified in the initial search process were also examined for any additional studies appropriate for the review. SAMe is an important physiologic compound, playing a central role as precursor molecule in several biochemical reactions. Numerous studies have shown that SAMe may affect the regulation of various critical components of monoaminergic neurotransmission involved in the pathophysiology of MDD. Some findings have suggested its antidepressant efficacy in treating MDD. Several randomized controlled trials have supported that the antidepressant efficacy of SAMe in monotherapy is superior to placebo and tricyclic antidepressants. Recent findings have also demonstrated its efficacy in patients nonresponsive to selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors. Overall, SAMe is a well-tolerated medication, which may offer considerable advantages as an alternative to antidepressant drugs or as an add-on therapy in the treatment of MDD and TRD. More large-scale controlled trials are needed to gain a better understanding of the relative efficacy of this drug.

Methyl group balance in brain and liver: role of choline on increased S-adenosyl methionine (SAM) demand by chronic arsenic exposure.

Science.gov (United States)

Ríos, Rosalva; Santoyo, Martha E; Cruz, Daniela; Delgado, Juan Manuel; Zarazúa, Sergio; Jiménez-Capdeville, María E

2012-11-30

Arsenic toxicity has been related to its interference with one carbon metabolism, where a high demand of S-adenosylmethionine (SAM) for arsenic methylation as well as a failure of its regeneration would compromise the availability of methyl groups for diverse cellular functions. Since exposed animals show disturbances of methylated products such as methylated arginines, myelin and axon membranes, this work investigates whether alterations of SAM, choline and phosphatidylcholine (PC) in the brain of arsenic exposed rats are associated with myelin alterations and myelin basic protein (MBP) immunoreactivity. Also these metabolites, morphologic and biochemical markers of methyl group alterations were analyzed in the liver, the main site of arsenic methylation. In adult, life-long arsenic exposed rats through drinking water (3 ppm), no changes of SAM, choline and PC concentrations where found in the brain, but SAM and PC were severely decreased in liver accompanied by a significant increase of choline. These results suggest that choline plays an important role as methyl donor in arsenic exposure, which could underlie hepatic affections observed when arsenic exposure is combined with other environmental factors. Also, important myelin and nerve fiber alterations, accompanied by a 75% decrease of MBP immunoreactivity were not associated with a SAM deficit in the brain. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Methionine metabolism in apple tissue: implications of S-adenosylmethionine as an intermediate in the conversion of methionine to ethylene

International Nuclear Information System (INIS)

Adams, D.O.; Yang, S.F.

1977-01-01

If S-adenosylmethionine (SAM) is the direct precursor of ethylene as previously proposed, it is expected that 5'-S-methyl-5'-thioadenosine (MTA) would be the fragment nucleoside. When [Me- 14 C] or ( 35 S)methionine was fed to climacteric apple (Malus sylvestris Mill) tissue, radioactive 5-S-methyl-5-thioribose (MTR) was identified as the predominant product and MTA as a minor one. When the conversion of methionine into ethylene was inhibited by L-2-amino-4-(2'-amino-ethoxy)-trans-3-butenoic acid, the conversion of ( 35 S) or (Me- 14 C)methionine into MTR was similarly inhibited. Furthermore, the formation of MTA and MTR from ( 35 S)methionine was observed only in climacteric tissue which produced ethylene and actively converted methionine to ethylene but not in preclimacteric tissue which did not produce ethylene or convert methionine to ethylene. These observations suggest that the conversion of methionine into MTA and MTR is closely related to ethylene biosynthesis and provide indirect evidence that SAM may be an intermediate in the conversion of methionine to ethylene. When ( 35 S)MTA was fed to climacteric or preclimacteric apple tissue, radioactivity was efficiently incorporated into MTR and methionine. However, when ( 35 S)MTR was administered, radioactivity was efficiently incorporated into methionine but not MTA. A scheme is presented for the production of ethylene from methionine

Structural basis for recognition of S-adenosylhomocysteine by riboswitches

Energy Technology Data Exchange (ETDEWEB)

Edwards, A.L.; Heroux, A.; Reyes, F. E.; Batey, R. T.

2010-11-01

S-adenosyl-(L)-homocysteine (SAH) riboswitches are regulatory elements found in bacterial mRNAs that up-regulate genes involved in the S-adenosyl-(L)-methionine (SAM) regeneration cycle. To understand the structural basis of SAH-dependent regulation by RNA, we have solved the structure of its metabolite-binding domain in complex with SAH. This structure reveals an unusual pseudoknot topology that creates a shallow groove on the surface of the RNA that binds SAH primarily through interactions with the adenine ring and methionine main chain atoms and discriminates against SAM through a steric mechanism. Chemical probing and calorimetric analysis indicate that the unliganded RNA can access bound-like conformations that are significantly stabilized by SAH to direct folding of the downstream regulatory switch. Strikingly, we find that metabolites bearing an adenine ring, including ATP, bind this aptamer with sufficiently high affinity such that normal intracellular concentrations of these compounds may influence regulation of the riboswitch.

Structural Basis for Recognition of S-adenosylhomocysteine by Riboswitches

Energy Technology Data Exchange (ETDEWEB)

A Edwards; F Reyes; A Heroux; R Batey

2011-12-31

S-adenosyl-(L)-homocysteine (SAH) riboswitches are regulatory elements found in bacterial mRNAs that up-regulate genes involved in the S-adenosyl-(L)-methionine (SAM) regeneration cycle. To understand the structural basis of SAH-dependent regulation by RNA, we have solved the structure of its metabolite-binding domain in complex with SAH. This structure reveals an unusual pseudoknot topology that creates a shallow groove on the surface of the RNA that binds SAH primarily through interactions with the adenine ring and methionine main chain atoms and discriminates against SAM through a steric mechanism. Chemical probing and calorimetric analysis indicate that the unliganded RNA can access bound-like conformations that are significantly stabilized by SAH to direct folding of the downstream regulatory switch. Strikingly, we find that metabolites bearing an adenine ring, including ATP, bind this aptamer with sufficiently high affinity such that normal intracellular concentrations of these compounds may influence regulation of the riboswitch.

Temporal study of acetaminophen (APAP) and S-adenosyl-L-methionine (SAMe) effects on subcellular hepatic SAMe levels and methionine adenosyltransferase (MAT) expression and activity

International Nuclear Information System (INIS)

Brown, J. Michael; Ball, John G.; Hogsett, Amy; Williams, Tierra; Valentovic, Monica

2010-01-01

Acetaminophen (APAP) is the leading cause of drug induced liver failure in the United States. Previous studies in our laboratory have shown that S-adenosyl methionine (SAMe) is protective for APAP hepatic toxicity. SAMe is critical for glutathione synthesis and transmethylation of nucleic acids, proteins and phospholipids which would facilitate recovery from APAP toxicity. SAMe is synthesized in cells through the action of methionine adenosyltransferase (MAT). This study tested the hypothesis that total hepatic and subcellular SAMe levels are decreased by APAP toxicity. Studies further examined MAT expression and activity in response to APAP toxicity. Male C57BL/6 mice (16-22 g) were treated with vehicle (Veh; water 15 ml/kg ip injections), 250 mg/kg APAP (15 ml/kg, ip), SAMe (1.25 mmol/kg) or SAMe administered 1 h after APAP injection (SAMe and SAMe + APAP). Hepatic tissue was collected 2, 4, and 6 h after APAP administration. Levels of SAMe and its metabolite S-adenosylhomocysteine (SAH) were determined by HPLC analysis. MAT expression was examined by Western blot. MAT activity was determined by fluorescence assay. Total liver SAMe levels were depressed at 4 h by APAP overdose, but not at 2 or 6 h. APAP depressed mitochondrial SAMe levels at 4 and 6 h relative to the Veh group. In the nucleus, levels of SAMe were depressed below detectable limits 4 h following APAP administration. SAMe administration following APAP (SAMe + APAP) prevented APAP associated decline in mitochondrial and nuclear SAMe levels. In conclusion, the maintenance of SAMe may provide benefit in preventing damage associated with APAP toxicity.

Targeting S-adenosylmethionine biosynthesis with a novel allosteric inhibitor of Mat2A

Energy Technology Data Exchange (ETDEWEB)

Quinlan, Casey L.; Kaiser, Stephen E.; Bolaños, Ben; Nowlin, Dawn; Grantner, Rita; Karlicek-Bryant, Shannon; Feng, Jun Li; Jenkinson, Stephen; Freeman-Cook, Kevin; Dann, Stephen G.; Wang, Xiaoli; Wells, Peter A.; Fantin, Valeria R.; Stewart, Al E.; Grant, Stephan K. (Pfizer)

2017-05-29

S-Adenosyl-L-methionine (SAM) is an enzyme cofactor used in methyl transfer reactions and polyamine biosynthesis. The biosynthesis of SAM from ATP and L-methionine is performed by the methionine adenosyltransferase enzyme family (Mat; EC 2.5.1.6). Human methionine adenosyltransferase 2A (Mat2A), the extrahepatic isoform, is often deregulated in cancer. We identified a Mat2A inhibitor, PF-9366, that binds an allosteric site on Mat2A that overlaps with the binding site for the Mat2A regulator, Mat2B. Studies exploiting PF-9366 suggested a general mode of Mat2A allosteric regulation. Allosteric binding of PF-9366 or Mat2B altered the Mat2A active site, resulting in increased substrate affinity and decreased enzyme turnover. These data support a model whereby Mat2B functions as an inhibitor of Mat2A activity when methionine or SAM levels are high, yet functions as an activator of Mat2A when methionine or SAM levels are low. The ramification of Mat2A activity modulation in cancer cells is also described.

Purification, crystallization and preliminary crystallographic studies of plant S-adenosyl-l-homocysteine hydrolase (Lupinus luteus)

Energy Technology Data Exchange (ETDEWEB)

Brzezinski, Krzysztof [Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan (Poland); Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan (Poland); Bujacz, Grzegorz [Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan (Poland); Faculty of Food Chemistry and Biotechnology, Technical University of Lodz (Poland); Jaskolski, Mariusz, E-mail: mariuszj@amu.edu.pl [Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan (Poland); Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan (Poland)

2008-07-01

Single crystals of recombinant S-adenosyl-l-homocysteine hydrolase from L. luteus in complex with adenosine diffract X-rays to 1.17 Å resolution at 100 K. The crystals are tetragonal, space group P4{sub 3}2{sub 1}2, and contain one copy of the dimeric enzyme in the asymmetric unit. By degrading S-adenosyl-l-homocysteine, which is a byproduct of S-adenosyl-l-methionine-dependent methylation reactions, S-adenosyl-l-homocysteine hydrolase (SAHase) acts as a regulator of cellular methylation processes. S-Adenosyl-l-homocysteine hydrolase from the leguminose plant yellow lupin (Lupinus luteus), LlSAHase, which is composed of 485 amino acids and has a molecular weight of 55 kDa, has been cloned, expressed in Escherichia coli and purified. Crystals of LlSAHase in complex with adenosine were obtained by the hanging-drop vapour-diffusion method using 20%(w/v) PEG 4000 and 10%(v/v) 2-propanol as precipitants in 0.1 M Tris–HCl buffer pH 8.0. The crystals were tetragonal, space group P4{sub 3}2{sub 1}2, with unit-cell parameters a = 122.4, c = 126.5 Å and contained two protein molecules in the asymmetric unit, corresponding to the functional dimeric form of the enzyme. Atomic resolution (1.17 Å) X-ray diffraction data have been collected using synchrotron radiation.

Purification, crystallization and preliminary crystallographic studies of plant S-adenosyl-l-homocysteine hydrolase (Lupinus luteus)

International Nuclear Information System (INIS)

Brzezinski, Krzysztof; Bujacz, Grzegorz; Jaskolski, Mariusz

2008-01-01

Single crystals of recombinant S-adenosyl-l-homocysteine hydrolase from L. luteus in complex with adenosine diffract X-rays to 1.17 Å resolution at 100 K. The crystals are tetragonal, space group P4 3 2 1 2, and contain one copy of the dimeric enzyme in the asymmetric unit. By degrading S-adenosyl-l-homocysteine, which is a byproduct of S-adenosyl-l-methionine-dependent methylation reactions, S-adenosyl-l-homocysteine hydrolase (SAHase) acts as a regulator of cellular methylation processes. S-Adenosyl-l-homocysteine hydrolase from the leguminose plant yellow lupin (Lupinus luteus), LlSAHase, which is composed of 485 amino acids and has a molecular weight of 55 kDa, has been cloned, expressed in Escherichia coli and purified. Crystals of LlSAHase in complex with adenosine were obtained by the hanging-drop vapour-diffusion method using 20%(w/v) PEG 4000 and 10%(v/v) 2-propanol as precipitants in 0.1 M Tris–HCl buffer pH 8.0. The crystals were tetragonal, space group P4 3 2 1 2, with unit-cell parameters a = 122.4, c = 126.5 Å and contained two protein molecules in the asymmetric unit, corresponding to the functional dimeric form of the enzyme. Atomic resolution (1.17 Å) X-ray diffraction data have been collected using synchrotron radiation

A simple radioactivity assay for measurement of methionine adenosyltransferase activity by aqueous chromatography

International Nuclear Information System (INIS)

Oeztuerk, M.; Lemonnier, F.; Cresteil, D.; Lemonnier, A.

1983-01-01

Methionine adenosyltransferase (ATP:L-methionine S-adenosyltransferase, EC 2.5.1.6) catalyzes the formation of S-adenosyl-L-methionine from ATP and L-methionine. Methionine metabolism is very important in human pathology. Methionine adenosyltransferase deficiency has recently been shown to be a specific enzymatic defect, whereas certain other diseases have only been associated with non-specific deficiencies of methionine adenosyltransferase. These different reasons explain the existence of numerous reports concerning the determination of hepatic methionine adenosyltransferase and of its isozymic forms, found in different tissues in man and rat. On the basis of the work of Chou and Lombardini, the authors report a rapid, sensitive technique using aqueous chromatography with phosphocellulose ion exchange paper to separate the S-adenosyl L-[methyl- 14 C]methionine from L-[methyl- 14 C]methionine. (Auth.)

S-adenosyl methionine prevents ASD like behaviors triggered by early postnatal valproic acid exposure in very young mice.

Science.gov (United States)

Ornoy, Asher; Weinstein-Fudim, Liza; Tfilin, Matanel; Ergaz, Zivanit; Yanai, Joseph; Szyf, Moshe; Turgeman, Gadi

2018-01-16

A common animal model of ASD is the one induced by valproic acid (VPA), inducing epigenetic changes and oxidative stress. We studied the possible preventive effect of the methyl donor for epigenetic enzymatic reactions, S-adenosine methionine (SAM), on ASD like behavioral changes and on redox potential in the brain and liver in this model. ICR albino mice were injected on postnatal day 4 with one dose of 300 mg/kg of VPA, with normal saline (controls) or with VPA and SAM that was given orally for 3 days at the dose of 30 mg/kg body weight. From day 50, we carried out neurobehavioral tests and assessment of the antioxidant status of the prefrontal cerebral cortex, liver assessing SOD and CAT activity, lipid peroxidation and the expression of antioxidant genes. Mice injected with VPA exhibited neurobehavioral deficits typical of ASD that were more prominent in males. Changes in the activity of SOD and CAT increased lipid peroxidation and changes in the expression of antioxidant genes were observed in the prefrontal cortex of VPA treated mice, more prominent in females, while ASD like behavior was more prominent in males. There were no changes in the redox potential of the liver. The co-administration of VPA and SAM alleviated most ASD like neurobehavioral symptoms and normalized the redox potential in the prefrontal cortex. Early postnatal VPA administration induces ASD like behavior that is more severe in males, while the redox status changes are more severe in females; SAM corrects both. VPA-induced ASD seems to result from epigenetic changes, while the redox status changes may be secondary. Copyright © 2018. Published by Elsevier Inc.

Characterization of Trypanosoma brucei brucei S-adenosyl-L-methionine decarboxylase and its inhibition by Berenil, pentamidine and methylglyoxal bis(guanylhydrazone).

Science.gov (United States)

Bitonti, A J; Dumont, J A; McCann, P P

1986-01-01

Trypanosoma brucei brucei S-adenosyl-L-methionine (AdoMet) decarboxylase was found to be relatively insensitive to activation by putrescine as compared with the mammalian enzyme, being stimulated by only 50% over a 10,000-fold range of putrescine concentrations. The enzyme was not stimulated by up to 10 mM-Mg2+. The Km for AdoMet was 30 microM, similar to that of other eukaryotic AdoMet decarboxylases. T.b. brucei AdoMet decarboxylase activity was apparently irreversibly inhibited in vitro by Berenil and reversibly by pentamidine and methylglyoxal bis(guanylhydrazone). Berenil also inhibited trypanosomal AdoMet decarboxylase by 70% within 4 h after administration to infected rats and markedly increased the concentration of putrescine in trypanosomes that were exposed to the drug in vivo. Spermidine and spermine blocked the curative effect of Berenil on model mouse T.b. brucei infections. This effect of the polyamines was probably not due to reversal of Berenil's inhibitory effects on the AdoMet decarboxylase. PMID:3800910

A New Structural Form in the SAM/Metal-Dependent O;#8209;Methyltransferase Family: MycE from the Mycinamicin Biosynthetic Pathway

Energy Technology Data Exchange (ETDEWEB)

Akey, David L.; Li, Shengying; Konwerski, Jamie R.; Confer, Laura A.; Bernard, Steffen M.; Anzai, Yojiro; Kato, Fumio; Sherman, David H.; Smith, Janet L. (Michigan); (Toho)

2012-08-01

O-linked methylation of sugar substituents is a common modification in the biosynthesis of many natural products and is catalyzed by multiple families of S-adenosyl-l-methionine (SAM or AdoMet)-dependent methyltransferases (MTs). Mycinamicins, potent antibiotics from Micromonospora griseorubida, can be methylated at two positions on a 6-deoxyallose substituent. The first methylation is catalyzed by MycE, a SAM- and metal-dependent MT. Crystal structures were determined for MycE bound to the product S-adenosyl-l-homocysteine (AdoHcy) and magnesium, both with and without the natural substrate mycinamicin VI. This represents the first structure of a natural product sugar MT in complex with its natural substrate. MycE is a tetramer of a two-domain polypeptide, comprising a C-terminal catalytic MT domain and an N-terminal auxiliary domain, which is important for quaternary assembly and for substrate binding. The symmetric MycE tetramer has a novel MT organization in which each of the four active sites is formed at the junction of three monomers within the tetramer. The active-site structure supports a mechanism in which a conserved histidine acts as a general base, and the metal ion helps to position the methyl acceptor and to stabilize a hydroxylate intermediate. A conserved tyrosine is suggested to support activity through interactions with the transferred methyl group from the SAM methyl donor. The structure of the free enzyme reveals a dramatic order-disorder transition in the active site relative to the S-adenosyl-L-homocysteine complexes, suggesting a mechanism for product/substrate exchange through concerted movement of five loops and the polypeptide C-terminus.

A viral protein promotes host SAMS1 activity and ethylene production for the benefit of virus infection.

Science.gov (United States)

Zhao, Shanshan; Hong, Wei; Wu, Jianguo; Wang, Yu; Ji, Shaoyi; Zhu, Shuyi; Wei, Chunhong; Zhang, Jinsong; Li, Yi

2017-10-10

Ethylene plays critical roles in plant development and biotic stress response, but the mechanism of ethylene in host antiviral response remains unclear. Here, we report that Rice dwarf virus (RDV) triggers ethylene production by stimulating the activity of S-adenosyl-L-methionine synthetase (SAMS), a key component of the ethylene synthesis pathway, resulting in elevated susceptibility to RDV. RDV-encoded Pns11 protein specifically interacted with OsSAMS1 to enhance its enzymatic activity, leading to higher ethylene levels in both RDV-infected and Pns11-overexpressing rice. Consistent with a counter-defense role for ethylene, Pns11-overexpressing rice, as well as those overexpressing OsSAMS1 , were substantially more susceptible to RDV infection, and a similar effect was observed in rice plants treated with an ethylene precursor. Conversely, OsSAMS1- knockout mutants, as well as an osein2 mutant defective in ethylene signaling, resisted RDV infection more robustly. Our findings uncover a novel mechanism which RDV manipulates ethylene biosynthesis in the host plants to achieve efficient infection.

Post-translational modification of ribosomally synthesized peptides by a radical SAM epimerase in Bacillus subtilis

Science.gov (United States)

Benjdia, Alhosna; Guillot, Alain; Ruffié, Pauline; Leprince, Jérôme; Berteau, Olivier

2017-07-01

Ribosomally synthesized peptides are built out of L-amino acids, whereas D-amino acids are generally the hallmark of non-ribosomal synthetic processes. Here we show that the model bacterium Bacillus subtilis is able to produce a novel type of ribosomally synthesized and post-translationally modified peptide that contains D-amino acids, and which we propose to call epipeptides. We demonstrate that a two [4Fe-4S]-cluster radical S-adenosyl-L-methionine (SAM) enzyme converts L-amino acids into their D-counterparts by catalysing Cα-hydrogen-atom abstraction and using a critical cysteine residue as the hydrogen-atom donor. Unexpectedly, these D-amino acid residues proved to be essential for the activity of a peptide that induces the expression of LiaRS, a major component of the bacterial cell envelope stress-response system. Present in B. subtilis and in several members of the human microbiome, these epipeptides and radical SAM epimerases broaden the landscape of peptidyl structures accessible to living organisms.

Palliative treatment for advanced biliary adenocarcinomas with combination dimethyl sulfoxide-sodium bicarbonate infusion and S-adenosyl-L-methionine.

Science.gov (United States)

Hoang, Ba X; Tran, Hung Q; Vu, Ut V; Pham, Quynh T; Shaw, D Graeme

2014-09-01

Adenocarcinoma of the gallbladder and cholangiocarcinoma account for 4% and 3%, respectively, of all gastrointestinal cancers. Advanced biliary tract carcinoma has a very poor prognosis with all current available modalities of treatment. In this pilot open-label study, the authors investigated the efficacy and safety of a combination of dimethyl sulfoxide-sodium bicarbonate (DMSO-SB) infusion and S-adenosyl-L-methionine (ademetionine) oral supplementation as palliative pharmacotherapy in nine patients with advanced nonresectable biliary tract carcinomas (ABTCs). Patients with evidence of biliary obstruction with a total serum bilirubin ≤300 μmol/L were allowed to join the study. The results of this 6-month study and follow-up of all nine patients with ABTC indicated that the investigated combination treatment improved pain control, blood biochemical parameters, and quality of life for the patients. Moreover, this method of treatment has led to a 6-month progression-free survival for all investigated patients. The treatment was well tolerated for all patients without major adverse reactions. Given that ABTC is a highly fatal malignancy with poor response to chemotherapy and targeted drugs, the authors consider that the combination of DMSO-SB and ademetionine deserves further research and application as a palliative care and survival-enhancing treatment for this group of patients.

Purification of 1-aminocyclopropane-1-carboxylate synthase from apple fruits using s-adenosyl [3,414C]-methionine (SAM) as a probe

International Nuclear Information System (INIS)

Yip, Wingkip; Dong, Jianguo; Yang, Shang Fa

1989-01-01

Tomato ACC synthase is inactivated by its substrate SAM, with the moiety of aminobutyrate being covalently linked to ACC synthase during the catalytic reactions. A partial purified ACC synthase (the catalytic activity 100 μmol/h·mg protein) from pellets of apple extract was incubated with [3,4 14 C] SAM. Only one radioactive peak was revealed in a C-4 reverse phase HPLC and one radioactive band on SDS-PAGE with an M.W. of 48 kDa. Apple ACC synthase in native form is resistant to V8, α-chromtrypsin and carboxylpeptidase A digestion, but effectively inactivated by trypsin and ficin, as demonstrated by both the activity assay and SAM labeling. The radioactive protein cut from the SDS-PAGE was injected to three mice, two of the mice showed responses to the protein in western blot analysis. The antibodies from mice is currently under characterization

Necrosis-Driven Systemic Immune Response Alters SAM Metabolism through the FOXO-GNMT Axis

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Fumiaki Obata

2014-05-01

Full Text Available Sterile inflammation triggered by endogenous factors is thought to contribute to the pathogenesis of acute and chronic inflammatory diseases. Here, we demonstrate that apoptosis-deficient mutants spontaneously develop a necrosis-driven systemic immune response in Drosophila and provide an in vivo model for studying the organismal response to sterile inflammation. Metabolomic analysis of hemolymph from apoptosis-deficient mutants revealed increased sarcosine and reduced S-adenosyl-methionine (SAM levels due to glycine N-methyltransferase (Gnmt upregulation. We showed that Gnmt was elevated in response to Toll activation induced by the local necrosis of wing epidermal cells. Necrosis-driven inflammatory conditions induced dFoxO hyperactivation, leading to an energy-wasting phenotype. Gnmt was cell-autonomously upregulated by dFoxO in the fat body as a possible rheostat for controlling energy loss, which functioned during fasting as well as inflammatory conditions. We propose that the dFoxO-Gnmt axis is essential for the maintenance of organismal SAM metabolism and energy homeostasis.

Suppression of a methionine synthase by calmodulin under environmental stress in the entomopathogenic fungus Beauveria bassiana.

Science.gov (United States)

Kim, Jiyoung; Oh, Junsang; Yoon, Deok-Hyo; Sung, Gi-Ho

2017-10-01

Methionine synthase (MetE, EC 2.1.1.14) catalyses the final step in the methionine biosynthetic pathway. Methionine biosynthesis plays a major role in protein biogenesis and is the source of S-adenosyl methionine (SAM), the universal donor of methyl groups. In this study, we demonstrated that BbMetE acts as a typical MetE enzyme in the entomopathogenic fungus Beauveria bassiana. In addition, we found that BbMetE binds to calmodulin (CaM) in vitro and in vivo. The functional role of CaM binding to BbMetE was to negatively regulate BbMetE activity in B. bassiana. Our proton-nuclear magnetic resonance data revealed that CaM inhibitor W-7 increases methionine content in B. bassiana, suggesting that CaM negatively regulates the BbMetE activity. Environmental stress stimuli such as salt, H 2 O 2 and heat suppressed BbMetE activity in B. bassiana. W-7 reversed this effect, suggesting that the inhibitory mechanism is mediated through stimulation of CaM activity. Therefore, this work suggests that BbMetE plays an important role in methionine biosynthesis, which is mediated by environmental stress stimuli via the CaM signalling pathway. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

SAM-dependent enzyme-catalysed pericyclic reactions in natural product biosynthesis

Science.gov (United States)

Ohashi, Masao; Liu, Fang; Hai, Yang; Chen, Mengbin; Tang, Man-Cheng; Yang, Zhongyue; Sato, Michio; Watanabe, Kenji; Houk, K. N.; Tang, Yi

2017-09-01

Pericyclic reactions—which proceed in a concerted fashion through a cyclic transition state—are among the most powerful synthetic transformations used to make multiple regioselective and stereoselective carbon-carbon bonds. They have been widely applied to the synthesis of biologically active complex natural products containing contiguous stereogenic carbon centres. Despite the prominence of pericyclic reactions in total synthesis, only three naturally existing enzymatic examples (the intramolecular Diels-Alder reaction, and the Cope and the Claisen rearrangements) have been characterized. Here we report a versatile S-adenosyl-L-methionine (SAM)-dependent enzyme, LepI, that can catalyse stereoselective dehydration followed by three pericyclic transformations: intramolecular Diels-Alder and hetero-Diels-Alder reactions via a single ambimodal transition state, and a retro-Claisen rearrangement. Together, these transformations lead to the formation of the dihydropyran core of the fungal natural product, leporin. Combined in vitro enzymatic characterization and computational studies provide insight into how LepI regulates these bifurcating biosynthetic reaction pathways by using SAM as the cofactor. These pathways converge to the desired biosynthetic end product via the (SAM-dependent) retro-Claisen rearrangement catalysed by LepI. We expect that more pericyclic biosynthetic enzymatic transformations remain to be discovered in naturally occurring enzyme ‘toolboxes’. The new role of the versatile cofactor SAM is likely to be found in other examples of enzyme catalysis.

Characterization of the Candida albicans Amino Acid Permease Family: Gap2 Is the Only General Amino Acid Permease and Gap4 Is an S-Adenosylmethionine (SAM) Transporter Required for SAM-Induced Morphogenesis

Czech Academy of Sciences Publication Activity Database

Kraidlová, Lucie; Schrevens, S.; Tournu, H.; Van Zeebroeck, G.; Sychrová, Hana; Van Dijck, P.

2016-01-01

Roč. 1, č. 6 (2016), č. článku e00284-16. ISSN 2379-5042 R&D Projects: GA ČR(CZ) GA16-03398S Institutional support: RVO:67985823 Keywords : Candida albicans * GAP1 * S-adenosyl methionine * general amino acid permease * morphogenesis Subject RIV: EE - Microbiology, Virology

Small Molecule Inhibitors That Selectively Block Dengue Virus Methyltransferase*

OpenAIRE

Lim, Siew Pheng; Sonntag, Louis Sebastian; Noble, Christian; Nilar, Shahul H.; Ng, Ru Hui; Zou, Gang; Monaghan, Paul; Chung, Ka Yan; Dong, Hongping; Liu, Boping; Bodenreider, Christophe; Lee, Gladys; Ding, Mei; Chan, Wai Ling; Wang, Gang

2010-01-01

Crystal structure analysis of Flavivirus methyltransferases uncovered a flavivirus-conserved cavity located next to the binding site for its cofactor, S-adenosyl-methionine (SAM). Chemical derivatization of S-adenosyl-homocysteine (SAH), the product inhibitor of the methylation reaction, with substituents that extend into the identified cavity, generated inhibitors that showed improved and selective activity against dengue virus methyltransferase (MTase), but not related human enzymes. Crysta...

Why Nature Uses Radical SAM Enzymes so Widely: Electron Nuclear Double Resonance Studies of Lysine 2,3-Aminomutase Show the 5'-dAdo• "Free Radical" Is Never Free.

Science.gov (United States)

Horitani, Masaki; Byer, Amanda S; Shisler, Krista A; Chandra, Tilak; Broderick, Joan B; Hoffman, Brian M

2015-06-10

Lysine 2,3-aminomutase (LAM) is a radical S-adenosyl-L-methionine (SAM) enzyme and, like other members of this superfamily, LAM utilizes radical-generating machinery comprising SAM anchored to the unique Fe of a [4Fe-4S] cluster via a classical five-membered N,O chelate ring. Catalysis is initiated by reductive cleavage of the SAM S-C5' bond, which creates the highly reactive 5'-deoxyadenosyl radical (5'-dAdo•), the same radical generated by homolytic Co-C bond cleavage in B12 radical enzymes. The SAM surrogate S-3',4'-anhydroadenosyl-L-methionine (anSAM) can replace SAM as a cofactor in the isomerization of L-α-lysine to L-β-lysine by LAM, via the stable allylic anhydroadenosyl radical (anAdo•). Here electron nuclear double resonance (ENDOR) spectroscopy of the anAdo• radical in the presence of (13)C, (2)H, and (15)N-labeled lysine completes the picture of how the active site of LAM from Clostridium subterminale SB4 "tames" the 5'-dAdo• radical, preventing it from carrying out harmful side reactions: this "free radical" in LAM is never free. The low steric demands of the radical-generating [4Fe-4S]/SAM construct allow the substrate target to bind adjacent to the S-C5' bond, thereby enabling the 5'-dAdo• radical created by cleavage of this bond to react with its partners by undergoing small motions, ∼0.6 Å toward the target and ∼1.5 Å overall, that are controlled by tight van der Waals contact with its partners. We suggest that the accessibility to substrate and ready control of the reactive C5' radical, with "van der Waals control" of small motions throughout the catalytic cycle, is common within the radical SAM enzyme superfamily and is a major reason why these enzymes are the preferred means of initiating radical reactions in nature.

Crystallization of mouse S-adenosyl-l-homocysteine hydrolase

International Nuclear Information System (INIS)

Ishihara, Masaaki; Kusakabe, Yoshio; Ohsumichi, Tsuyoshi; Tanaka, Nobutada; Nakanishi, Masayuki; Kitade, Yukio; Nakamura, Kazuo T.

2010-01-01

Mouse S-adenosyl-l-homocysteine hydrolase has been crystallized in the presence of the reaction product adenosine. Diffraction data to 1.55 Å resolution were collected using synchrotron radiation. S-Adenosyl-l-homocysteine hydrolase (SAHH; EC 3.3.1.1) catalyzes the reversible hydrolysis of S-adenosyl-l-homocysteine to adenosine and l-homocysteine. For crystallographic investigations, mouse SAHH (MmSAHH) was overexpressed in bacterial cells and crystallized using the hanging-drop vapour-diffusion method in the presence of the reaction product adenosine. X-ray diffraction data to 1.55 Å resolution were collected from an orthorhombic crystal form belonging to space group I222 with unit-cell parameters a = 100.64, b = 104.44, c = 177.31 Å. Structural analysis by molecular replacement is in progress

Why Nature Uses Radical SAM Enzymes so Widely: Electron Nuclear Double Resonance Studies of Lysine 2,3-Aminomutase Show the 5′-dAdo• “Free Radical” Is Never Free

Science.gov (United States)

Horitani, Masaki; Byer, Amanda S.; Shisler, Krista A.; Chandra, Tilak; Broderick, Joan B.; Hoffman, Brian M.

2015-01-01

Lysine 2,3-aminomutase (LAM) is a radical S-adenosyl-L-methionine (SAM) enzyme and, like other members of this superfamily, LAM utilizes radical-generating machinery comprising SAM anchored to the unique Fe of a [4Fe-4S] cluster via a classical five-membered N,O chelate ring. Catalysis is initiated by reductive cleavage of the SAM S–C5′ bond, which creates the highly reactive 5′-deoxyadenosyl radical (5′-dAdo•), the same radical generated by homolytic Co–C bond cleavage in B12 radical enzymes. The SAM surrogate S-3′,4′-anhydroadenosyl-L-methionine (anSAM) can replace SAM as a cofactor in the isomerization of L-α-lysine to L-β-lysine by LAM, via the stable allylic anhydroadenosyl radical (anAdo•). Here electron nuclear double resonance (ENDOR) spectroscopy of the anAdo• radical in the presence of 13C, 2H, and 15N-labeled lysine completes the picture of how the active site of LAM from Clostridium subterminale SB4 “tames” the 5′-dAdo• radical, preventing it from carrying out harmful side reactions: this “free radical” in LAM is never free. The low steric demands of the radical-generating [4Fe-4S]/SAM construct allow the substrate target to bind adjacent to the S–C5′ bond, thereby enabling the 5′-dAdo• radical created by cleavage of this bond to react with its partners by undergoing small motions, ~0.6 Å toward the target and ~1.5 Å overall, that are controlled by tight van der Waals contact with its partners. We suggest that the accessibility to substrate and ready control of the reactive C5′ radical, with “van der Waals control” of small motions throughout the catalytic cycle, is common within the radical SAM enzyme superfamily and is a major reason why these enzymes are the preferred means of initiating radical reactions in nature. PMID:25923449

Methionine Metabolites in Patients With Sepsis.

Science.gov (United States)

Wexler, Orren; Gough, Michael S; Morgan, Mary Anne M; Mack, Cynthia M; Apostolakos, Michael J; Doolin, Kathleen P; Mooney, Robert A; Arning, Erland; Bottiglieri, Teodoro; Pietropaoli, Anthony P

2018-01-01

Sepsis is characterized by microvascular dysfunction and thrombophilia. Several methionine metabolites may be relevant to this sepsis pathophysiology. S-adenosylmethionine (SAM) serves as the methyl donor for trans-methylation reactions. S-adenosylhomocysteine (SAH) is the by-product of these reactions and serves as the precursor to homocysteine. Relationships between plasma total homocysteine concentrations (tHcy) and vascular disease and thrombosis are firmly established. We hypothesized that SAM, SAH, and tHcy levels are elevated in patients with sepsis and associated with mortality. This was a combined case-control and prospective cohort study consisting of 109 patients with sepsis and 50 control participants without acute illness. The study was conducted in the medical and surgical intensive care units of the University of Rochester Medical Center. Methionine, SAM, SAH, and tHcy concentrations were compared in patients with sepsis versus control participants and in sepsis survivors versus nonsurvivors. Patients with sepsis had significantly higher plasma SAM and SAH concentrations than control participants (SAM: 164 [107-227] vs73 [59-87 nM], P sepsis patients compared to healthy control participants (4 [2-6]) vs 7 [5-9] μM; P = .04). In multivariable analysis, quartiles of SAM, SAH, and tHcy were independently associated with sepsis ( P = .006, P = .05, and P Sepsis nonsurvivors had significantly higher plasma SAM and SAH concentrations than survivors (SAM: 223 [125-260] vs 136 [96-187] nM; P = .01; SAH: 139 [81-197] vs 86 [55-130] nM, P = .006). Plasma tHcy levels were similar in survivors vs nonsurvivors. The associations between SAM or SAH and hospital mortality were no longer significant after adjusting for renal dysfunction. Methionine metabolite concentrations are abnormal in sepsis and linked with clinical outcomes. Further study is required to determine whether these abnormalities have pathophysiologic significance.

Monovalent Cation Activation of the Radical SAM Enzyme Pyruvate Formate-Lyase Activating Enzyme.

Science.gov (United States)

Shisler, Krista A; Hutcheson, Rachel U; Horitani, Masaki; Duschene, Kaitlin S; Crain, Adam V; Byer, Amanda S; Shepard, Eric M; Rasmussen, Ashley; Yang, Jian; Broderick, William E; Vey, Jessica L; Drennan, Catherine L; Hoffman, Brian M; Broderick, Joan B

2017-08-30

Pyruvate formate-lyase activating enzyme (PFL-AE) is a radical S-adenosyl-l-methionine (SAM) enzyme that installs a catalytically essential glycyl radical on pyruvate formate-lyase. We show that PFL-AE binds a catalytically essential monovalent cation at its active site, yet another parallel with B 12 enzymes, and we characterize this cation site by a combination of structural, biochemical, and spectroscopic approaches. Refinement of the PFL-AE crystal structure reveals Na + as the most likely ion present in the solved structures, and pulsed electron nuclear double resonance (ENDOR) demonstrates that the same cation site is occupied by 23 Na in the solution state of the as-isolated enzyme. A SAM carboxylate-oxygen is an M + ligand, and EPR and circular dichroism spectroscopies reveal that both the site occupancy and the identity of the cation perturb the electronic properties of the SAM-chelated iron-sulfur cluster. ENDOR studies of the PFL-AE/[ 13 C-methyl]-SAM complex show that the target sulfonium positioning varies with the cation, while the observation of an isotropic hyperfine coupling to the cation by ENDOR measurements establishes its intimate, SAM-mediated interaction with the cluster. This monovalent cation site controls enzyme activity: (i) PFL-AE in the absence of any simple monovalent cations has little-no activity; and (ii) among monocations, going down Group 1 of the periodic table from Li + to Cs + , PFL-AE activity sharply maximizes at K + , with NH 4 + closely matching the efficacy of K + . PFL-AE is thus a type I M + -activated enzyme whose M + controls reactivity by interactions with the cosubstrate, SAM, which is bound to the catalytic iron-sulfur cluster.

Early diagnosis of adenylosuccinate lyase deficiency using a high-throughput screening method and a trial of oral S-adenosyl-l-methionine as a treatment method.

Science.gov (United States)

van Werkhoven, Michiel A; Duley, John A; McGown, Ivan; Munce, Teresa; Freeman, Jeremy L; Pitt, James J

2013-11-01

The aim of this study was to develop a high-throughput urine screening technique for adenylosuccinate lyase (ADSL) deficiency and to evaluate S-adenosyl-l-methionine (SAMe) as a potential treatment for this disorder. Testing for succinyladenosine (S-Ado), a marker of ADSL deficiency, was incorporated into a screening panel for urine biomarkers for inborn errors of metabolism using electrospray tandem mass spectrometry. Liquid chromatography-mass spectrometry and high-performance liquid chromatography were used to confirm and monitor the response of metabolites to oral SAMe treatment. Increased levels of S-Ado were detected in a 3-month-old male infant with hypotonia and seizures. ADSL gene sequencing revealed a previously described c.-49T>C mutation and a novel c.889_891dupAAT mutation, which was likely to disrupt enzyme function. After 9 months of SAMe treatment, there was no clear response evidenced in urine metabolite levels or clinical parameters. These results demonstrate proof of the principle for the high-throughput urine screening technique, allowing earlier diagnosis of patients with ADSL deficiency. However, early treatment with SAMe does not appear to be effective in ADSL deficiency. It is suggested that although SAMe treatment may ameliorate purine nucleotide deficiency, it cannot correct metabolic syndromes in which a toxic nucleotide is present, in this case presumed to be succinylaminoimidazole carboxamide ribotide. © 2013 Mac Keith Press.

Characterization of a SAM-dependent fluorinase from a latent biosynthetic pathway for fluoroacetate and 4-fluorothreonine formation in Nocardia brasiliensis.

Science.gov (United States)

Wang, Yaya; Deng, Zixin; Qu, Xudong

2014-01-01

Fluorination has been widely used in chemical synthesis, but is rare in nature. The only known biological fluorination scope is represented by the fl pathway from Streptomyces cattleya that produces fluoroacetate (FAc) and 4-fluorothreonine (4-FT). Here we report the identification of a novel pathway for FAc and 4-FT biosynthesis from the actinomycetoma-causing pathogen Nocardia brasiliensis ATCC 700358. The new pathway shares overall conservation with the fl pathway in S. cattleya. Biochemical characterization of the conserved domains revealed a novel fluorinase NobA that can biosynthesize 5'-fluoro-5'-deoxyadenosine (5'-FDA) from inorganic fluoride and S-adenosyl-l-methionine (SAM). The NobA shows similar halide specificity and characteristics to the fluorination enzyme FlA of the fl pathway. Kinetic parameters for fluoride ( K m 4153 μM, k cat 0.073 min (-1)) and SAM ( K m 416 μM, k cat 0.139 min (-1)) have been determined, revealing that NobA is slightly (2.3 fold) slower than FlA. Upon sequence comparison, we finally identified a distinct loop region in the fluorinases that probably accounts for the disparity of fluorination activity.

Evaluation of S-adenosyl l-methionine in a double-blinded, randomized, placebo-controlled, clinical trial for treatment of presumptive osteoarthritis in the dog.

Science.gov (United States)

Imhoff, Darren J; Gordon-Evans, Wanda J; Evans, Richard B; Johnson, Ann L; Griffon, Dominique J; Swanson, Kelly S

2011-02-01

To evaluate the efficacy of S-adenosyl l-methionine (SAMe) in the treatment of clinically inferred canine osteoarthritis (OA). Six weeks, double-blinded, placebo-controlled, clinical trial. Dogs (n=33) with clinical signs, history, and orthopedic exams consistent with OA. Dogs were block randomized by body condition score (goniometry, and the Canine Brief Pain Inventory (CBPI) at the time of study entrance and at 3 and 6 weeks after entry. Groups were compared using parametric and nonparametric paired tests as appropriate, and numbers needed to treat (NNT) were calculated for the CBPI and peak vertical force (PVF). Both groups (n=15 placebo, n=18 SAMe) had a reduction in mean PVF (P=.02) and vertical impulse (VI; P=.06) from the 1st to 3rd visit. There was no significant difference between the placebo group and SAMe group for PVF, VI, or either part of the CBPI (Severity or Impact). The NNT at 6 weeks for the Severity score was 3, Impact score was 25, and PVF was 45. These data do not support the use of SAMe as an effective stand alone treatment for reducing clinical signs of OA, as measured by PVF, VI, goniometry, CBPI (both Severity and Impact), and examination score within 6 weeks of treatment. © Copyright 2011 by The American College of Veterinary Surgeons.

Drought stress provokes the down-regulation of methionine and ethylene biosynthesis pathways in Medicago truncatula roots and nodules.

Science.gov (United States)

Larrainzar, Estíbaliz; Molenaar, Johanna A; Wienkoop, Stefanie; Gil-Quintana, Erena; Alibert, Bénédicte; Limami, Anis M; Arrese-Igor, Cesar; González, Esther M

2014-09-01

Symbiotic nitrogen fixation is one of the first physiological processes inhibited in legume plants under water-deficit conditions. Despite the progress made in the last decades, the molecular mechanisms behind this regulation are not fully understood yet. Recent proteomic work carried out in the model legume Medicago truncatula provided the first indications of a possible involvement of nodule methionine (Met) biosynthesis and related pathways in response to water-deficit conditions. To better understand this involvement, the drought-induced changes in expression and content of enzymes involved in the biosynthesis of Met, S-adenosyl-L-methionine (SAM) and ethylene in M. truncatula root and nodules were analyzed using targeted approaches. Nitrogen-fixing plants were subjected to a progressive water deficit and a subsequent recovery period. Besides the physiological characterization of the plants, the content of total sulphur, sulphate and main S-containing metabolites was measured. Results presented here show that S availability is not a limiting factor in the drought-induced decline of nitrogen fixation rates in M. truncatula plants and provide evidences for a down-regulation of the Met and ethylene biosynthesis pathways in roots and nodules in response to water-deficit conditions. © 2014 John Wiley & Sons Ltd.

S-adenosyl-L-methionine protection of acetaminophen mediated oxidative stress and identification of hepatic 4-hydroxynonenal protein adducts by mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Brown, James Mike [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Kuhlman, Christopher [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Terneus, Marcus V. [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Labenski, Matthew T. [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Lamyaithong, Andre Benja; Ball, John G. [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Lau, Serrine S. [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Valentovic, Monica A., E-mail: Valentov@marshall.edu [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States)

2014-12-01

Acetaminophen (APAP) hepatotoxicity is protected by S-adenosyl-L-methionine (SAMe) treatment 1 hour (h) after APAP in C57/Bl6 mice. This study examined protein carbonylation as well as mitochondrial and cytosolic protein adduction by 4-hydroxynonenal (4-HNE) using mass spectrometry (MS) analysis. Additional studies investigated the leakage of mitochondrial proteins and 4-HNE adduction of these proteins. Male C57/Bl6 mice (n = 5/group) were divided into the following groups and treated as indicated: Veh (15 ml/kg water, ip), SAMe (1.25 mmol/kg, ip), APAP (250 mg/kg), and SAMe given 1 h after APAP (S + A). APAP toxicity was confirmed by an increase (p < 0.05) in plasma ALT (U/l) and liver weight/10 g body weight relative to the Veh, SAMe and S + A groups 4 h following APAP treatment. SAMe administered 1 h post-APAP partially corrected APAP hepatotoxicity as ALT and liver weight/10 g body weights were lower in the S + A group compared the APAP group. APAP induced leakage of the mitochondrial protein, carbamoyl phosphate synthase-1 (CPS-1) into the cytosol and which was reduced in the S + A group. SAMe further reduced the extent of APAP mediated 4-HNE adduction of CPS-1. MS analysis of hepatic and mitochondrial subcellular fractions identified proteins from APAP treated mice. Site specific 4-HNE adducts were identified on mitochondrial proteins sarcosine dehydrogenase and carbamoyl phosphate synthase-1 (CPS-1). In summary, APAP is associated with 4-HNE adduction of proteins as identified by MS analysis and that CPS-1 leakage was greater in APAP treated mice. SAMe reduced the extent of 4-HNE adduction of proteins as well as leakage of CPS-1. - Highlights: • Acetaminophen (APAP) toxicity protected by S-adenosylmethionine (SAMe) • 4-Hydroxynonenal adducted to sarcosine dehydrogenase • 4-Hydroxynonenal adducted to carbamoyl phosphate synthetase-1 • SAMe reduced APAP mediated CPS-1 mitochondrial leakage.

S-adenosyl-L-methionine protection of acetaminophen mediated oxidative stress and identification of hepatic 4-hydroxynonenal protein adducts by mass spectrometry

International Nuclear Information System (INIS)

Brown, James Mike; Kuhlman, Christopher; Terneus, Marcus V.; Labenski, Matthew T.; Lamyaithong, Andre Benja; Ball, John G.; Lau, Serrine S.; Valentovic, Monica A.

2014-01-01

Acetaminophen (APAP) hepatotoxicity is protected by S-adenosyl-L-methionine (SAMe) treatment 1 hour (h) after APAP in C57/Bl6 mice. This study examined protein carbonylation as well as mitochondrial and cytosolic protein adduction by 4-hydroxynonenal (4-HNE) using mass spectrometry (MS) analysis. Additional studies investigated the leakage of mitochondrial proteins and 4-HNE adduction of these proteins. Male C57/Bl6 mice (n = 5/group) were divided into the following groups and treated as indicated: Veh (15 ml/kg water, ip), SAMe (1.25 mmol/kg, ip), APAP (250 mg/kg), and SAMe given 1 h after APAP (S + A). APAP toxicity was confirmed by an increase (p < 0.05) in plasma ALT (U/l) and liver weight/10 g body weight relative to the Veh, SAMe and S + A groups 4 h following APAP treatment. SAMe administered 1 h post-APAP partially corrected APAP hepatotoxicity as ALT and liver weight/10 g body weights were lower in the S + A group compared the APAP group. APAP induced leakage of the mitochondrial protein, carbamoyl phosphate synthase-1 (CPS-1) into the cytosol and which was reduced in the S + A group. SAMe further reduced the extent of APAP mediated 4-HNE adduction of CPS-1. MS analysis of hepatic and mitochondrial subcellular fractions identified proteins from APAP treated mice. Site specific 4-HNE adducts were identified on mitochondrial proteins sarcosine dehydrogenase and carbamoyl phosphate synthase-1 (CPS-1). In summary, APAP is associated with 4-HNE adduction of proteins as identified by MS analysis and that CPS-1 leakage was greater in APAP treated mice. SAMe reduced the extent of 4-HNE adduction of proteins as well as leakage of CPS-1. - Highlights: • Acetaminophen (APAP) toxicity protected by S-adenosylmethionine (SAMe) • 4-Hydroxynonenal adducted to sarcosine dehydrogenase • 4-Hydroxynonenal adducted to carbamoyl phosphate synthetase-1 • SAMe reduced APAP mediated CPS-1 mitochondrial leakage

Insights into the reactivation of cobalamin-dependent methionine synthase

Energy Technology Data Exchange (ETDEWEB)

Koutmos, Markos; Datta, Supratim; Pattridge, Katherine A.; Smith, Janet L.; Matthews, Rowena G.; (Michigan)

2009-12-10

Cobalamin-dependent methionine synthase (MetH) is a modular protein that catalyzes the transfer of a methyl group from methyltetrahydrofolate to homocysteine to produce methionine and tetrahydrofolate. The cobalamin cofactor, which serves as both acceptor and donor of the methyl group, is oxidized once every {approx}2,000 catalytic cycles and must be reactivated by the uptake of an electron from reduced flavodoxin and a methyl group from S-adenosyl-L-methionine (AdoMet). Previous structures of a C-terminal fragment of MetH (MetH{sup CT}) revealed a reactivation conformation that juxtaposes the cobalamin- and AdoMet-binding domains. Here we describe 2 structures of a disulfide stabilized MetH{sup CT} ({sub s-s}MetH{sup CT}) that offer further insight into the reactivation of MetH. The structure of {sub s-s}MetH{sup CT} with cob(II)alamin and S-adenosyl-L-homocysteine represents the enzyme in the reactivation step preceding electron transfer from flavodoxin. The structure supports earlier suggestions that the enzyme acts to lower the reduction potential of the Co(II)/Co(I) couple by elongating the bond between the cobalt and its upper axial water ligand, effectively making the cobalt 4-coordinate, and illuminates the role of Tyr-1139 in the stabilization of this 4-coordinate state. The structure of {sub s-s}MetH{sub CT} with aquocobalamin may represent a transient state at the end of reactivation as the newly remethylated 5-coordinate methylcobalamin returns to the 6-coordinate state, triggering the rearrangement to a catalytic conformation.

Deregulation of S-adenosylmethionine biosynthesis and regeneration improves methylation in the E. coli de novo vanillin biosynthesis pathway.

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Kunjapur, Aditya M; Hyun, Jason C; Prather, Kristala L J

2016-04-11

Vanillin is an industrially valuable molecule that can be produced from simple carbon sources in engineered microorganisms such as Saccharomyces cerevisiae and Escherichia coli. In E. coli, de novo production of vanillin was demonstrated previously as a proof of concept. In this study, a series of data-driven experiments were performed in order to better understand limitations associated with biosynthesis of vanillate, which is the immediate precursor to vanillin. Time-course experiments monitoring production of heterologous metabolites in the E. coli de novo vanillin pathway revealed a bottleneck in conversion of protocatechuate to vanillate. Perturbations in central metabolism intended to increase flux into the heterologous pathway increased average vanillate titers from 132 to 205 mg/L, but protocatechuate remained the dominant heterologous product on a molar basis. SDS-PAGE, in vitro activity measurements, and L-methionine supplementation experiments suggested that the decline in conversion rate was influenced more by limited availability of the co-substrate S-adenosyl-L-methionine (AdoMet or SAM) than by loss of activity of the heterologous O-methyltransferase. The combination of metJ deletion and overexpression of feedback-resistant variants of metA and cysE, which encode enzymes involved in SAM biosynthesis, increased average de novo vanillate titers by an additional 33% (from 205 to 272 mg/L). An orthogonal strategy intended to improve SAM regeneration through overexpression of native mtn and luxS genes resulted in a 25% increase in average de novo vanillate titers (from 205 to 256 mg/L). Vanillate production improved further upon supplementation with methionine (as high as 419 ± 58 mg/L), suggesting potential for additional enhancement by increasing SAM availability. Results from this study demonstrate context dependency of engineered pathways and highlight the limited methylation capacity of E. coli. Unlike in previous efforts to improve SAM or

Traumatic brain injury alters methionine metabolism: implications for pathophysiology

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Pramod K Dash

2016-04-01

Full Text Available Methionine is an essential proteinogenic amino acid that is obtained from the diet. In addition to its requirement for protein biosynthesis, methionine is metabolized to generate metabolites that play key roles in a number of cellular functions. Metabolism of methionine via the transmethylation pathway generates S-adenosylmethionine (SAM that serves as the principal methyl (-CH3 donor for DNA and histone methyltransferases to regulate epigenetic changes in gene expression. SAM is also required for methylation of other cellular proteins that serve various functions and phosphatidylcholine synthesis that participate in cellular signaling.. Under conditions of oxidative stress, homocysteine (which is derived from SAM enters the transsulfuration pathway to generate glutathione, an important cytoprotective molecule against oxidative damage. As both experimental and clinical studies have shown that traumatic brain injury (TBI alters DNA and histone methylation and causes oxidative stress, we examined if TBI alters the plasma levels of methionine and its metabolites in human patients. Blood samples were collected from healthy volunteers (n = 20 and patients with mild TBI (GCS > 12; n = 20 or severe TBI (GCS < 8; n = 20 within the first 24 hours of injury. The levels of methionine and its metabolites in the plasma samples were analyzed by either liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry (LC-MS or GC-MS. Severe TBI decreased the levels of methionine, SAM, betaine and 2-methylglycine as compared to healthy volunteers, indicating a decrease in metabolism through the transmethylation cycle. In addition, precursors for the generation of glutathione, cysteine and glycine were also found to be decreased as were intermediate metabolites of the gamma-glutamyl cycle (gamma-glutamyl amino acids and 5-oxoproline. Mild TBI also decreased the levels of methionine, α-ketobutyrate, 2 hydroxybutyrate and glycine, albeit to lesser

S-Adenosylmethionine and S-adenosylhomocystein metabolism in isolated rat liver. Effects of L-methionine, L-homocystein, and adenosine.

Science.gov (United States)

Hoffman, D R; Marion, D W; Cornatzer, W E; Duerre, J A

1980-11-25

The effects of varying concentrations of L-methionine, L-homocysteine, and adenosine on the tissue levels of S-adenosylmethionine (AdoMet) and S-adenosyl-homocystein (AdoHcy) were investigated in perfused liver. In the normal liver, the intracellular concentration of AdoMet was dependent upon the availability of methionine. In the presence of high concentrations of methionine the maximum level of AdoMet attainable was 300 nmol/g of liver. The exogenous concentration of methionine did not alter the hepatic concentration of AdoHcy (8 to 20 nmol/g) while adenosine or homocysteine blocked hydrolysis of AdoHcy resulting in elevated levels of AdoHcy (400 to 600 nmol/g) and AdoMet (300 to 600 nmol/g). The addition of both adenosine (4mM) and homocysteine (3.4 mM) to the perfusate further increased the levels of AdoHcy (4 mumol/g) and AdoMet (1.2 mumol/g). As the concentration of AdoHcy increased, significant amounts of this compound were released into the perfusate, while AdoMet was not detected. Under all conditions where AdoHcy accumulated in the cell, a concomitant increase in the AdoMet level occurred. Apparently AdoHcy acts as a positive effector of the S-adenosylmethionine synthase. The hepatocytes did not take up significant amounts of [methyl-14C]AdoMet from the perfusate nor were any [14C]methyl groups from this compound incorporated into histones, DNA, or phospholipids. In contrast, [14C]methyl groups were readily incorporated into these macromolecules from exogenous [methyl-14C]methionine. The addition of adenosine (4 mM) and homocystein (3.4 mM) shifted the AdoMet:AdoHcy ratio from 8.2 to 0.3. Under these conditions, transmethylation was inhibited markedly.

Cloning, expression, purification, crystallization and preliminary X-ray analysis of NodS N-methyltransferase from Bradyrhizobium japonicum WM9

International Nuclear Information System (INIS)

Cakici, Ozgur; Sikorski, Michal; Stepkowski, Tomasz; Bujacz, Grzegorz; Jaskolski, Mariusz

2008-01-01

The NodS N-methyltransferase, an enzyme participating in the biosynthesis of the bacterial nodulation (Nod) factor necessary to establish symbiotic nitrogen fixation with a legume plant host, has been crystallized in the apo form as well as in complex with SAH. SAH is a byproduct of SAM degradation during the SAM-dependent methylation reaction. The Nod factor (NF) is a rhizobial signal molecule that is involved in recognition of a legume host and the formation of root and stem nodules. Some unique enzymes are involved in the biosynthesis of NF, which is a variously but specifically substituted lipochitooligosaccharide. One of these enzymes is NodS, an N-methyltransferase that methylates end-deacetylated chitooligosaccharide substrates. In the methylation reaction, NodS uses S-adenosyl-l-methionine (SAM) as a methyl donor. To date, no structural information is available about NodS from any rhizobium. X-ray crystallographic studies of the NodS protein from Bradyrhizobium japonicum WM9, which infects the legumes lupin and serradella, have been undertaken. The nodS gene was cloned and the recombinant protein was expressed in Escherichia coli cells using natural amino acids and as an SeMet derivative. NodS without ligands was crystallized in the presence of PEG 3350 and MgCl 2 . The protein was also crystallized in complex with S-adenosyl-l-homocysteine (SAH) in the presence of PEG 8000 and MgCl 2 . SAH is produced from SAM as a byproduct of the methylation reaction. The crystals of apo NodS are tetragonal and diffracted X-rays to 2.42 Å resolution. The NodS–SAH complex crystallizes in an orthorhombic space group and the crystals diffracted X-rays to 1.85 Å resolution

Suppression of LFA-1 expression by spermine is associated with enhanced methylation of ITGAL, the LFA-1 promoter area.

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Yoshihiko Kano

Full Text Available Spermine and spermidine, natural polyamines, suppress lymphocyte function-associated antigen 1 (LFA-1 expression and its associated cellular functions through mechanisms that remain unknown. Inhibition of ornithine decarboxylase, which is required for polyamine synthesis, in Jurkat cells by 3 mM D,L-alpha-difluoromethylornithine hydrochloride (DFMO significantly decreased spermine and spermidine concentrations and was associated with decreased DNA methyltransferase (Dnmt activity, enhanced demethylation of the LFA-1 gene (ITGAL promoter area, and increased CD11a expression. Supplementation with extracellular spermine (500 µM of cells pretreated with DFMO significantly increased polyamine concentrations, increased Dnmt activity, enhanced methylation of the ITGAL promoter, and decreased CD11a expression. It has been shown that changes in intracellular polyamine concentrations affect activities of -adenosyl-L-methionine-decaroboxylase, and, as a result, affect concentrations of the methyl group donor, S-adenosylmethionine (SAM, and of the competitive Dnmt inhibitor, decarboxylated SAM. Additional treatments designed to increase the amount of SAM and decrease the amount of decarboxylated SAM-such as treatment with methylglyoxal bis-guanylhydrazone (an inhibitor of S-adenosyl-L-methionine-decaroboxylase and SAM supplementation-successfully decreased CD11a expression. Western blot analyses revealed that neither DFMO nor spermine supplementation affected the amount of active Ras-proximate-1, a member of the Ras superfamily of small GTPases and a key protein for regulation of CD11a expression. The results of this study suggest that polyamine-induced suppression of LFA-1 expression occurs via enhanced methylation of ITGAL.

RNA-Seq and iTRAQ Reveal the Dwarfing Mechanism of Dwarf Polish Wheat (Triticum polonicum L.).

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Wang, Yi; Xiao, Xue; Wang, Xiaolu; Zeng, Jian; Kang, Houyang; Fan, Xing; Sha, Lina; Zhang, Haiqin; Zhou, Yonghong

2016-01-01

The dwarfing mechanism of Rht-dp in dwarf Polish wheat (DPW) is unknown. Each internode of DPW was significantly shorter than it in high Polish wheat (HPW), and the dwarfism was insensitive to photoperiod, abscisic acid (ABA), gibberellin (GA), cytokinin (CK), auxin and brassinolide (BR). To understand the mechanism, three sets of transcripts, DPW, HPW, and a chimeric set (a combination of DPW and HPW), were constructed using RNA sequencing (RNA-Seq). Based on the chimeric transcripts, 2,446 proteins were identified using isobaric tags for relative and absolute quantification (iTRAQ). A total of 108 unigenes and 12 proteins were considered as dwarfism-related differentially expressed genes (DEGs) and differentially expressed proteins (DEPs), respectively. Among of these DEGs and DEPs, 6 DEGs and 6 DEPs were found to be involved in flavonoid and S-adenosyl-methionine (SAM) metabolisms; 5 DEGs and 3 DEPs were involved in cellulose metabolism, cell wall plasticity and cell expansion; 2 DEGs were auxin transporters; 2 DEPs were histones; 1 DEP was a peroxidase. These DEGs and DEPs reduced lignin and cellulose contents, increased flavonoid content, possibly decreased S-adenosyl-methionine (SAM) and polyamine contents and increased S-adenosyl-L-homocysteine hydrolase (SAHH) content in DPW stems, which could limit auxin transport and reduce extensibility of the cell wall, finally limited cell expansion (the cell size of DPW was significantly smaller than HPW cells) and caused dwarfism in DPW.

Targeting methionine cycle as a potential therapeutic strategy for immune disorders.

Science.gov (United States)

Li, Heng; Lu, Huimin; Tang, Wei; Zuo, Jianping

2017-08-23

Methionine cycle plays an essential role in regulating many cellular events, especially transmethylation reactions, incorporating the methyl donor S-adenosylmethionine (SAM). The transmethylations and substances involved in the cycle have shown complicated effects and mechanisms on immunocytes developments and activations, and exert crucial impacts on the pathological processes in immune disorders. Areas covered: Methionine cycle has been considered as an effective means of drug developments. This review discussed the role of methionine cycle in immune responses and summarized the potential therapeutic strategies based on the cycle, including SAM analogs, methyltransferase inhibitors, S-adenosylhomocysteine hydrolase (SAHH) inhibitors, adenosine receptors specific agonists or antagonists and homocysteine (Hcy)-lowering reagents, in treating human immunodeficiency virus (HIV) infections, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), systemic sclerosis (SSc) and other immune disorders. Expert opinion: New targets and biomarkers grown out of methionine cycle have developed rapidly in the past decades. However, impacts of epigenetic regulations on immune disorders are unclear and whether the substances in methionine cycle can be clarified as biomarkers remains controversial. Therefore, further elucidation on the role of epigenetic regulations and substances in methionine cycle may contribute to exploring the cycle-derived biomarkers and drugs in immune disorders.

A novel multifunctional O-methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine

OpenAIRE

Li, Laigeng; Popko, Jacqueline L.; Zhang, Xing-Hai; Osakabe, Keishi; Tsai, Chung-Jui; Joshi, Chandrashekhar P.; Chiang, Vincent L.

1997-01-01

S-adenosyl-l-methionine (SAM)-dependent O-methyltransferases (OMTs) catalyze the methylation of hydroxycinnamic acid derivatives for the synthesis of methylated plant polyphenolics, including lignin. The distinction in the extent of methylation of lignins in angiosperms and gymnosperms, mediated by substrate-specific OMTs, represents one of the fundamental differences in lignin biosynthesis between these two classes of plants. In angiosperms, two types of structurally and functionally distinc...

Structures of a putative RNA 5-methyluridine methyltransferase, Thermus thermophilus TTHA1280, and its complex with S-adenosyl-l-homocysteine

International Nuclear Information System (INIS)

Pioszak, Augen A.; Murayama, Kazutaka; Nakagawa, Noriko; Ebihara, Akio; Kuramitsu, Seiki; Shirouzu, Mikako; Yokoyama, Shigeyuki

2005-01-01

Three structures of a putative RNA 5-methyluridine methyltransferase from T. thermophilus, including its complex with S-adenosyl-l-homocysteine, are presented. The structures reveal the mode of cofactor binding, architecture of the putative active site, and the presence of a deep cleft adjacent to the active site that may bind RNA. The Thermus thermophilus hypothetical protein TTHA1280 belongs to a family of predicted S-adenosyl-l-methionine (AdoMet) dependent RNA methyltransferases (MTases) present in many bacterial and archaeal species. Inspection of amino-acid sequence motifs common to class I Rossmann-fold-like MTases suggested a specific role as an RNA 5-methyluridine MTase. Selenomethionine (SeMet) labelled and native versions of the protein were expressed, purified and crystallized. Two crystal forms of the SeMet-labelled apoprotein were obtained: SeMet-ApoI and SeMet-ApoII. Cocrystallization of the native protein with S-adenosyl-l-homocysteine (AdoHcy) yielded a third crystal form, Native-AdoHcy. The SeMet-ApoI structure was solved by the multiple anomalous dispersion method and refined at 2.55 Å resolution. The SeMet-ApoII and Native-AdoHcy structures were solved by molecular replacement and refined at 1.80 and 2.60 Å, respectively. TTHA1280 formed a homodimer in the crystals and in solution. Each subunit folds into a three-domain structure composed of a small N-terminal PUA domain, a central α/β-domain and a C-terminal Rossmann-fold-like MTase domain. The three domains form an overall clamp-like shape, with the putative active site facing a deep cleft. The architecture of the active site is consistent with specific recognition of uridine and catalysis of methyl transfer to the 5-carbon position. The cleft is suitable in size and charge distribution for binding single-stranded RNA.

Characterization of a SAM-dependent fluorinase from a latent biosynthetic pathway for fluoroacetate and 4-fluorothreonine formation in Nocardia brasiliensis [v1; ref status: indexed, http://f1000r.es/2tz

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Yaya Wang

2014-02-01

Full Text Available Fluorination has been widely used in chemical synthesis, but is rare in nature. The only known biological fluorination scope is represented by the fl pathway from Streptomyces cattleya that produces fluoroacetate (FAc and 4-fluorothreonine (4-FT. Here we report the identification of a novel pathway for FAc and 4-FT biosynthesis from the actinomycetoma-causing pathogen Nocardia brasiliensis ATCC 700358. The new pathway shares overall conservation with the fl pathway in S. cattleya. Biochemical characterization of the conserved domains revealed a novel fluorinase NobA that can biosynthesize 5’-fluoro-5’-deoxyadenosine (5’-FDA from inorganic fluoride and S-adenosyl-l-methionine (SAM. The NobA shows similar halide specificity and characteristics to the fluorination enzyme FlA of the fl pathway. Kinetic parameters for fluoride (Km 4153 μM, kcat 0.073 min-1 and SAM (Km 416 μM, kcat 0.139 min-1 have been determined, revealing that NobA is slightly (2.3 fold slower than FlA. Upon sequence comparison, we finally identified a distinct loop region in the fluorinases that probably accounts for the disparity of fluorination activity.

Role of methionine on epigenetic modification of DNA methylation and gene expression in animals

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Naifeng Zhang

2018-03-01

Full Text Available DNA methylation is one of the main epigenetic phenomena affecting gene expression. It is an important mechanism for the development of embryo, growth and health of animals. As a key nutritional factor limiting the synthesis of protein, methionine serves as the precursor of S-adenosylmethionine (SAM in the hepatic one-carbon metabolism. The dietary fluctuation of methionine content can alter the levels of metabolic substrates in one-carbon metabolism, e.g., the SAM, S-adenosylhomocysteine (SAH, and change the expression of genes related to the growth and health of animals by DNA methylation reactions. The ratio of SAM to SAH is called ‘methylation index’ but it should be carefully explained because the complexity of methylation reaction. Alterations of methylation in a specific cytosine-guanine (CpG site, rather than the whole promoter region, might be enough to change gene expression. Aberrant methionine cycle may provoke molecular changes of one-carbon metabolism that results in deregulation of cellular hemostasis and health problems. The importance of DNA methylation has been underscored but the mechanisms of methionine affecting DNA methylation are poorly understood. Nutritional epigenomics provides a promising insight into the targeting epigenetic changes in animals from a nutritional standpoint, which will deepen and expand our understanding of genes, molecules, tissues, and animals in which methionine alteration influences DNA methylation and gene expression. Keywords: Epigenetics, Methionine, DNA methylation, Gene expression, Epigenetic modification

A paradigm shift for radical SAM reactions: The organometallic intermediate Ω is central to catalysis.

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Byer, Amanda S; Yang, Hao; McDaniel, Elizabeth C; Kathiresan, Venkatesan; Impano, Stella; Pagnier, Adrien; Watts, Hope; Denler, Carly; Vagstad, Anna; Piel, Jörn; Duschene, Kaitlin S; Shepard, Eric M; Shields, Thomas P; Scott, Lincoln G; Lilla, Edward A; Yokoyama, Kenichi; Broderick, William E; Hoffman, Brian M; Broderick, Joan B

2018-06-28

Radical S-adenosyl-L-methionine (SAM) en-zymes comprise a vast superfamily catalyzing diverse reactions essential to all life through ho-molytic SAM cleavage to liberate the highly-reactive 5-deoxyadenosyl radical (5-dAdo•). Our recent observation of a catalytically compe-tent organometallic intermediate Ω that forms dur-ing reaction of the radical SAM (RS) enzyme py-ruvate formate-lyase activating-enzyme (PFL-AE) was therefore quite surprising, and led to the question of its broad relevance in the superfamily. We now show that Ω in PFL-AE forms as an in-termediate under a variety of mixing order condi-tions, suggesting it is central to catalysis in this enzyme. We further demonstrate that Ω forms in a suite of RS enzymes chosen to span the totality of superfamily reaction types, implicating Ω as essential in catalysis across the RS superfamily. Finally, EPR and electron nuclear double reso-nance spectroscopy establish that Ω involves an Fe-C5 bond between 5-dAdo• and the [4Fe-4S] cluster. An analogous organometallic bond is found in the well-known adenosylcobalamin (co-enzyme B12) cofactor used to initiate radical reac-tions via a 5'-dAdo• intermediate. Generation of a 5'-dAdo• intermediate via homolytic metal-carbon bond cleavage thus appears to be similar for Ω and coenzyme B12. However coenzyme B12 is involved in enzymes catalyzing of only a small number (~12) of distinct reactions, while the RS superfamily has more than 100,000 distinct se-quences and over 80 reaction types character-ized to date. The appearance of Ω across the RS superfamily therefore dramatically enlarges the sphere of bio-organometallic chemistry in Nature.

Unanticipated coordination of tris buffer to the Radical SAM cluster of the RimO methylthiotransferase.

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Molle, Thibaut; Clémancey, Martin; Latour, Jean-Marc; Kathirvelu, Velavan; Sicoli, Giuseppe; Forouhar, Farhad; Mulliez, Etienne; Gambarelli, Serge; Atta, Mohamed

2016-07-01

Radical SAM enzymes generally contain a [4Fe-4S](2+/1+) (RS cluster) cluster bound to the protein via the three cysteines of a canonical motif CxxxCxxC. The non-cysteinyl iron is used to coordinate SAM via its amino-carboxylate moiety. The coordination-induced proximity between the cluster acting as an electron donor and the adenosyl-sulfonium bond of SAM allows for the homolytic cleavage of the latter leading to the formation of the reactive 5'-deoxyadenosyl radical used for substrate activation. Most of the structures of Radical SAM enzymes have been obtained in the presence of SAM, and therefore, little is known about the situation when SAM is not present. In this report, we show that RimO, a methylthiotransferase belonging to the radical SAM superfamily, binds a Tris molecule in the absence of SAM leading to specific spectroscopic signatures both in Mössbauer and pulsed EPR spectroscopies. These data provide a cautionary note for researchers who work with coordinative unsaturated iron sulfur clusters.

Identification of a highly conserved domain in the EcoRII methyltransferase which can be photolabeled with S-adenosyl-L-[methyl-3H]methionine. Evidence for UV-induced transmethylation of cysteine 186

International Nuclear Information System (INIS)

Som, S.; Friedman, S.

1991-01-01

DNA methyltransferases can be photolabeled with S-adenosyl-L-methionine (AdoMet). Specific incorporation of radioactivity has been demonstrated after photolabeling with either [methyl-3H]AdoMet or [35S]AdoMet. The labeling is believed to occur at the AdoMet binding site. With the purpose of localizing the site responsible for [methyl-3H]AdoMet photolabeling, we cleaved the labeled EcoRII methyltransferase by chemical and enzymatic reactions and isolated the radiolabeled peptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and high pressure liquid chromatography. The labeled peptides were identified by amino-terminal sequencing. A common region was localized which accounted for 65-70% of the total label. This region includes a highly conserved core sequence present in all DNA (cytosine 5)-methyltransferases. One such fragment was digested further with chymotrypsin, and amino acid analysis of the resulting 3H-labeled peptide was consistent with the sequence Ala-Gly-Phe-Pro-(Cys)-Gln-Pro-Phe-Ser-Leu. However, the cysteine residue was not recovered as carboxymethylcysteine. The Pro-Cys bond was found to be protected from cleavage at cysteine residues after cyanylation. These results suggest that the cysteine residue is modified by the labeling reaction. The chymotryptic fragment was hydrolyzed enzymatically to single amino acids, and the labeled amino acid was identified as S-methylcysteine by thin layer chromatography. These results indicate that the cysteine residue is located at or close to the AdoMet binding site of EcoRII methyltransferase

Small Molecule Inhibitors That Selectively Block Dengue Virus Methyltransferase*

Science.gov (United States)

Lim, Siew Pheng; Sonntag, Louis Sebastian; Noble, Christian; Nilar, Shahul H.; Ng, Ru Hui; Zou, Gang; Monaghan, Paul; Chung, Ka Yan; Dong, Hongping; Liu, Boping; Bodenreider, Christophe; Lee, Gladys; Ding, Mei; Chan, Wai Ling; Wang, Gang; Jian, Yap Li; Chao, Alexander Theodore; Lescar, Julien; Yin, Zheng; Vedananda, T. R.; Keller, Thomas H.; Shi, Pei-Yong

2011-01-01

Crystal structure analysis of Flavivirus methyltransferases uncovered a flavivirus-conserved cavity located next to the binding site for its cofactor, S-adenosyl-methionine (SAM). Chemical derivatization of S-adenosyl-homocysteine (SAH), the product inhibitor of the methylation reaction, with substituents that extend into the identified cavity, generated inhibitors that showed improved and selective activity against dengue virus methyltransferase (MTase), but not related human enzymes. Crystal structure of dengue virus MTase with a bound SAH derivative revealed that its N6-substituent bound in this cavity and induced conformation changes in residues lining the pocket. These findings demonstrate that one of the major hurdles for the development of methyltransferase-based therapeutics, namely selectivity for disease-related methyltransferases, can be overcome. PMID:21147775

Methionine salvage pathway in relation to ethylene biosynthesis

International Nuclear Information System (INIS)

Miyazaki, J.H.

1987-01-01

The recycling of methionine during ethylene biosynthesis (the methionine cycle) was studied. During ethylene biosynthesis, the H 3 CS-group of S-adenosylmethionine (SAM) is released at 5'-methylthioadenosine (MTA), which is recycled to methionine via 5'-methylthioribose (MTS). In mungbean hypocotyls and cell-free extracts of avocado fruit, [ 14 C]MTR was converted to labeled methionine via 2-keto-4-methylthiobutyric acid (KMB) and 2-hydroxy-4-methylthiobutyric acid (HMB) as intermediates. Radioactive tracer studies showed that KMB was converted readily in vivo and in vitro to methionine, while HMB was converted much more slowly. The conversion of KMB to methionine by dialyzed avocado extract required an amino group donor. Among several potential donors tested, L-glutamine was the most efficient. Incubation of [ribose-U- 14 C]MTR with avocado extract resulted in the production of [ 14 C]formate, with little evolution of other 14 C-labeled one-carbon compounds, indicating that the conversion of MTR to KMB involves a loss of formate, presumably from C-1 of MTR

Redox Behavior of the S-Adenosylmethionine (SAM)-Binding Fe-S Cluster in Methylthiotransferase RimO, toward Understanding Dual SAM Activity.

Science.gov (United States)

Molle, Thibaut; Moreau, Yohann; Clemancey, Martin; Forouhar, Farhad; Ravanat, Jean-Luc; Duraffourg, Nicolas; Fourmond, Vincent; Latour, Jean-Marc; Gambarelli, Serge; Mulliez, Etienne; Atta, Mohamed

2016-10-18

RimO, a radical-S-adenosylmethionine (SAM) enzyme, catalyzes the specific C 3 methylthiolation of the D89 residue in the ribosomal S 12 protein. Two intact iron-sulfur clusters and two SAM cofactors both are required for catalysis. By using electron paramagnetic resonance, Mössbauer spectroscopies, and site-directed mutagenesis, we show how two SAM molecules sequentially bind to the unique iron site of the radical-SAM cluster for two distinct chemical reactions in RimO. Our data establish that the two SAM molecules bind the radical-SAM cluster to the unique iron site, and spectroscopic evidence obtained under strongly reducing conditions supports a mechanism in which the first molecule of SAM causes the reoxidation of the reduced radical-SAM cluster, impeding reductive cleavage of SAM to occur and allowing SAM to methylate a HS - ligand bound to the additional cluster. Furthermore, by using density functional theory-based methods, we provide a description of the reaction mechanism that predicts the attack of the carbon radical substrate on the methylthio group attached to the additional [4Fe-4S] cluster.

SAM-VI RNAs selectively bind S-adenosylmethionine and exhibit similarities to SAM-III riboswitches.

Science.gov (United States)

Mirihana Arachchilage, Gayan; Sherlock, Madeline E; Weinberg, Zasha; Breaker, Ronald R

2018-03-04

Five distinct riboswitch classes that regulate gene expression in response to the cofactor S-adenosylmethionine (SAM) or its metabolic breakdown product S-adenosylhomocysteine (SAH) have been reported previously. Collectively, these SAM- or SAH-sensing RNAs constitute the most abundant collection of riboswitches, and are found in nearly every major bacterial lineage. Here, we report a potential sixth member of this pervasive riboswitch family, called SAM-VI, which is predominantly found in Bifidobacterium species. SAM-VI aptamers selectively bind the cofactor SAM and strongly discriminate against SAH. The consensus sequence and structural model for SAM-VI share some features with the consensus model for the SAM-III riboswitch class, whose members are mainly found in lactic acid bacteria. However, there are sufficient differences between the two classes such that current bioinformatics methods separately cluster representatives of the two motifs. These findings highlight the abundance of RNA structures that can form to selectively recognize SAM, and showcase the ability of RNA to utilize diverse strategies to perform similar biological functions.

Crystal Structure of the Thermus thermophilus 16 S rRNA Methyltransferase RsmC in Complex with Cofactor and Substrate Guanosine

Energy Technology Data Exchange (ETDEWEB)

Demirci, H.; Gregory, S; Dahlberg, A; Jogl, G

2008-01-01

Post-transcriptional modification is a ubiquitous feature of ribosomal RNA in all kingdoms of life. Modified nucleotides are generally clustered in functionally important regions of the ribosome, but the functional contribution to protein synthesis is not well understood. Here we describe high resolution crystal structures for the N{sup 2}-guanine methyltransferase RsmC that modifies residue G1207 in 16 S rRNA near the decoding site of the 30 S ribosomal subunit. RsmC is a class I S-adenosyl-l-methionine-dependent methyltransferase composed of two methyltransferase domains. However, only one S-adenosyl-l-methionine molecule and one substrate molecule, guanosine, bind in the ternary complex. The N-terminal domain does not bind any cofactor. Two structures with bound S-adenosyl-l-methionine and S-adenosyl-l-homocysteine confirm that the cofactor binding mode is highly similar to other class I methyltransferases. Secondary structure elements of the N-terminal domain contribute to cofactor-binding interactions and restrict access to the cofactor-binding site. The orientation of guanosine in the active site reveals that G1207 has to disengage from its Watson-Crick base pairing interaction with C1051 in the 16 S rRNA and flip out into the active site prior to its modification. Inspection of the 30 S crystal structure indicates that access to G1207 by RsmC is incompatible with the native subunit structure, consistent with previous suggestions that this enzyme recognizes a subunit assembly intermediate.

Modification of S-Adenosyl-l-Homocysteine as Inhibitor of Nonstructural Protein 5 Methyltransferase Dengue Virus Through Molecular Docking and Molecular Dynamics Simulation.

Science.gov (United States)

Tambunan, Usman Sumo Friend; Nasution, Mochammad Arfin Fardiansyah; Azhima, Fauziah; Parikesit, Arli Aditya; Toepak, Erwin Prasetya; Idrus, Syarifuddin; Kerami, Djati

2017-01-01

Dengue fever is still a major threat worldwide, approximately threatening two-fifths of the world's population in tropical and subtropical countries. Nonstructural protein 5 (NS5) methyltransferase enzyme plays a vital role in the process of messenger RNA capping of dengue by transferring methyl groups from S -adenosyl-l-methionine to N7 atom of the guanine bases of RNA and the RNA ribose group of 2'OH, resulting in S -adenosyl-l-homocysteine (SAH). The modification of SAH compound was screened using molecular docking and molecular dynamics simulation, along with computational ADME-Tox (absorption, distribution, metabolism, excretion, and toxicity) test. The 2 simulations were performed using Molecular Operating Environment (MOE) 2008.10 software, whereas the ADME-Tox test was performed using various software. The modification of SAH compound was done using several functional groups that possess different polarities and properties, resulting in 3460 ligands to be docked. After conducting docking simulation, we earned 3 best ligands (SAH-M331, SAH-M2696, and SAH-M1356) based on ΔG binding and molecular interactions, which show better results than the standard ligands. Moreover, the results of molecular dynamics simulation show that the best ligands are still able to maintain the active site residue interaction with the binding site until the end of the simulation. After a series of molecular docking and molecular dynamics simulation were performed, we concluded that SAH-M1356 ligand is the most potential SAH-based compound to inhibit NS5 methyltransferase enzyme for treating dengue fever.

Insulin stimulation of phospholipid methylation in isolated rat adipocyte plasma membranes.

OpenAIRE

Kelly, K L; Kiechle, F L; Jarett, L

1984-01-01

Partially purified plasma membranes prepared from rat adipocytes contain N-methyltransferase(s) that utilize(s) S-adenosyl-L-methionine to synthesize phosphatidylcholine from phosphatidylethanolamine. The incorporation of [3H]methyl from S-adenosyl-L-[methyl-3H]methionine into plasma membrane phospholipids was linear with incubation time and plasma membrane protein concentration and was inhibited in a dose-dependent manner by both S-adenosyl-L-homocysteine and 3-deazadenosine. The addition of...

Monitoring of the specific radioactivity of S-adenosylmethionine in kidney in vivo

Energy Technology Data Exchange (ETDEWEB)

Stoecker, W; Roos, G; Lange, H W; Hempel, K [Wuerzburg Univ. (Germany, F.R.). Inst. fuer Medizinische Strahlenkunde

1977-02-01

The specific radioactivity of S-adenosylmethionine was followed in the cat kidney during the infusion of L-(Me-/sup 3/H)methionine into the corresponding renal artery. For this purpose /sup 14/C-labelled 4-(2-aminoethyl)pyrocatechol((/sup 14/C)dopamine) as methyl acceptor was injected locally every 15 min and the /sup 3/H and /sup 14/C activity of the methylation product homovanillic acid, isolated from urine, was measured. Approximately 5% of the /sup 14/C label is excreted during the first renal passage as (/sup 14/C)homovanillic acid. The specific activity of S-adenosyl(Me-/sup 3/H)methionine in the kidney was calculated from the known specific radioactivity of (/sup 14/C)dopamine injected and the measured radioactivity atio, /sup 3/H : /sup 14/C, of homovanillic acid isolated from urine. The specific activity of S-adenosyn(Me-/sup 3/H)methionine reaches a constant value in kidney about 30 to 60 min after the beginning of the L-(Me-/sup 3/H)methionine infusion. This plateau value was 28% +- 14% lower than the specific activity of L-(Me-/sup 3/H)methionine in the venous blood from the corresponding kidney. The difference between the specific radioactivity of S-adenosyl(Me-/sup 3/H)-methionine in kidney and of free methionine in plasma is explained by the existence of a methionine source of minor specific activity in the kidney. The average life span of S-adenosylmethionine in the kidney is 19.5 +- 8.9 min.

HERBAL METHIONINE (METHIOREP® IMPROVES GROWTH PERFORMANCE OF BROILER CHICKENS WITHOUT AFFECTING CARCASS CHARACTERISTICS AND BLOOD INDICES

Directory of Open Access Journals (Sweden)

O.J. Makinde

2017-05-01

Full Text Available Methiorep®, an herbal methionine premix, which is reported to contain herbal ingredients that mimic the activity of Methionine such as SAMe (S-Adenosyl Methionine and phosphatidyl choline, have recently introduced to Nigeria animal feed industry. An experiment was conducted with 120, one-week-old broilers to evaluate the effect of herbal methionine (methiorep® as substitute for synthetic methionine on growth performance of broiler chickens. Five isocaloric and isonitrogenous diets were formulated and Diet 1 (control, comprised of 0.25% methionine (NRC, 1994 while diet 2, 3, 4 and 5 comprised of 25%, 50%, 75% and 100% Methiorep® as substitute for methionine in the diets. The birds were randomly allocated to five experimental treatments, each treatment was replicated three times with eight birds per pen in a completely randomized design. The study lasted 49-days. The results of growth performance revealed that body weight gain, average feed intake and feed conversion ratio at both starter and finisher phases were not  influenced by dietary treatments (P>0.05. However cost per kg feed decreased as the level of Methiorep® increased in the diets (P0.05 by the dietary treatments. It was concluded that Methiorep® can completely substitute for Methionine in the diets of broiler chickens without adverse effect on growth performance, blood profiles and carcass yield of birds.

A histone H3K9M mutation traps histone methyltransferase Clr4 to prevent heterochromatin spreading

Energy Technology Data Exchange (ETDEWEB)

Shan, Chun-Min; Wang, Jiyong; Xu, Ke; Chen, Huijie; Yue, Jia-Xing; Andrews, Stuart; Moresco, James J.; Yates, John R.; Nagy, Peter L.; Tong, Liang; Jia, Songtao

2016-09-20

Histone lysine-to-methionine (K-to-M) mutations are associated with multiple cancers, and they function in a dominant fashion to block the methylation of corresponding lysines on wild type histones. However, their mechanisms of function are controversial. Here we show that in fission yeast, introducing the K9M mutation into one of the three histone H3 genes dominantly blocks H3K9 methylation on wild type H3 across the genome. In addition, H3K9M enhances the interaction of histone H3 tail with the H3K9 methyltransferase Clr4 in a SAM (S-adenosyl-methionine)-dependent manner, and Clr4 is trapped at nucleation sites to prevent its spreading and the formation of large heterochromatin domains. We further determined the crystal structure of an H3K9M peptide in complex with human H3K9 methyltransferase G9a and SAM, which reveales that the methionine side chain had enhanced van der Waals interactions with G9a. Therefore, our results provide a detailed mechanism by which H3K9M regulates H3K9 methylation.

Storifying Samsøs Renewable Energy Transition

DEFF Research Database (Denmark)

Papazu, Irina

2018-01-01

Through a joint community effort Denmark’s Renewable Energy Island Samsø became self-sufficient with renewable energy over a period of 10 years from 1997 to 2007. Today, the story about Samsø’s successful energy transition has become a global export and a widely known model of community building...... the effects of such well-crafted transition narratives. This tendency toward the ‘storification’ of transition processes is not restricted to Samsø; it is employed as a tactics by environmental organizations operating globally....

The phenotypic and molecular assessment of the non-conserved Arabidopsis MICRORNA163/S-ADENOSYL-METHYLTRANSFERASE regulatory module during biotic stress.

Science.gov (United States)

Litholdo, Celso Gaspar; Eamens, Andrew Leigh; Waterhouse, Peter Michael

2018-04-01

In plants, microRNAs (miRNAs) have evolved in parallel to the protein-coding genes that they target for expression regulation, and miRNA-directed gene expression regulation is central to almost every cellular process. MicroRNA, miR163, is unique to the Arabidopsis genus and is processed into a 24-nucleotide (nt) mature small regulatory RNA (sRNA) from a single precursor transcript transcribed from a single locus, the MIR163 gene. The MIR163 locus is a result of a recent inverted duplication event of one of the five closely related S-ADENOSYL-METHYLTRANSFERASE genes that the mature miR163 sRNA targets for expression regulation. Currently, however, little is known about the role of the miR163/S-ADENOSYL-METHYLTRANSFERASE regulatory module in response to biotic stress. Here, we document the expression domains of MIR163 and the S-ADENOSYL-METHYLTRANSFERASE target genes following fusion of their putative promoter sequences to the β-glucuronidase (GUS) reporter gene and subsequent in planta expression. Further, we report on our phenotypic and molecular assessment of Arabidopsis thaliana plants with altered miR163 accumulation, namely the mir163-1 and mir163-2 insertion knockout mutants and the miR163 overexpression line, the MIR163-OE plant. Finally, we reveal miR163 accumulation and S-ADENOSYL-METHYLTRANSFERASE target gene expression post treatment with the defence elicitors, salicylic acid and jasmonic acid, and following Fusarium oxysporum infection, wounding, and herbivory attack. Together, the work presented here provides a comprehensive new biological insight into the role played by the Arabidopsis genus-specific miR163/S-ADENOSYL-METHYLTRANSFERASE regulatory module in normal A. thaliana development and during the exposure of A. thaliana plants to biotic stress.

[Folates and fetal programming: role of epigenetics and epigenomics].

Science.gov (United States)

Guéant, Jean-Louis; Daval, Jean-Luc; Vert, Paul; Nicolas, Jean-Pierre

2012-12-01

Folates are needed for synthesis of methionine, the precursor of S-adenosyl methionine (SAM). They play therefore a key role in nutrition and epigenomics by fluxing monocarbons towards synthesis or methylation of DNA and RNA, and methylation of gene transregulators, respectively. The deficiency produces intrauterine growth retardation and birth dejects. Folate deficiency deregulates epigenomic mechanisms related to fetal programming through decreased cellular availability of SAM. Epigenetic mechanisms of folate deficiency are illustrated by inheritance of coat colour of agouti mice model and altered expression of Igf2/H19 imprinting genes. Dietary exposure to fumonisin FB1 acts synergistically with folate deficiency on alterations of heterochromatin assembly. Deficiency in folate and vitamin B12 produces impaired fatty acid oxidation in liver and heart through imbalanced methylation and acetylation of PGC1-alpha and decreased expression of SIRT1, and long-lasting cognitive disabilities through impaired hippocampal cell proliferation, differentiation and plasticity and atrophy of hippocampal CA1. Deciphering these mechanisms will help understand the discordances between experimental models and population studies on folate supplementation.

Crystal structures of the methyltransferase and helicase from the ZIKA 1947 MR766 Uganda strain

Energy Technology Data Exchange (ETDEWEB)

Bukrejewska, Malgorzata; Derewenda, Urszula; Radwanska, Malwina; Engel, Daniel A.; Derewenda, Zygmunt S.

2017-08-15

Two nonstructural proteins encoded byZika virusstrain MR766 RNA, a methyltransferase and a helicase, were crystallized and their structures were solved and refined at 2.10 and 2.01 Å resolution, respectively. The NS5 methyltransferase contains a boundS-adenosyl-L-methionine (SAM) co-substrate. The NS3 helicase is in the apo form. Comparison with published crystal structures of the helicase in the apo, nucleotide-bound and single-stranded RNA (ssRNA)-bound states suggests that binding of ssRNA to the helicase may occur through conformational selection rather than induced fit.

Diphthamide biosynthesis requires an organic radical generated by an iron-sulphur enzyme

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yang; Zhu, Xuling; Torelli, Andrew T; Lee, Michael; Dzikovski, Boris; Koralewski, Rachel M; Wang, Eileen; Freed, Jack; Krebs, Carsten; Ealick, Steve E; Lin, Hening [Cornell; (Penn)

2010-08-30

Archaeal and eukaryotic translation elongation factor 2 contain a unique post-translationally modified histidine residue called diphthamide, which is the target of diphtheria toxin. The biosynthesis of diphthamide was proposed to involve three steps, with the first being the formation of a C-C bond between the histidine residue and the 3-amino-3-carboxypropyl group of S-adenosyl-l-methionine (SAM). However, further details of the biosynthesis remain unknown. Here we present structural and biochemical evidence showing that the first step of diphthamide biosynthesis in the archaeon Pyrococcus horikoshii uses a novel iron-sulphur-cluster enzyme, Dph2. Dph2 is a homodimer and each of its monomers can bind a [4Fe-4S] cluster. Biochemical data suggest that unlike the enzymes in the radical SAM superfamily, Dph2 does not form the canonical 5'-deoxyadenosyl radical. Instead, it breaks the C_γ,Met-S bond of SAM and generates a 3-amino-3-carboxypropyl radical. Our results suggest that P. horikoshii Dph2 represents a previously unknown, SAM-dependent, [4Fe-4S]-containing enzyme that catalyses unprecedented chemistry.

The multi-state energy landscape of the SAM-I riboswitch: A single-molecule Förster resonance energy transfer spectroscopy study

Science.gov (United States)

Manz, Christoph; Kobitski, Andrei Yu.; Samanta, Ayan; Jäschke, Andres; Nienhaus, G. Ulrich

2018-03-01

RNA (ribonucleic acid) molecules are highly flexible biopolymers fluctuating at physiological temperatures among many different conformations that are represented by minima in a hierarchical conformational free energy landscape. Here we have employed single-molecule FRET (smFRET) to explore the energy landscape of the B. subtilis yitJ SAM-I riboswitch (RS). In this small RNA molecule, specific binding of an S-adenosyl-L-methionine (SAM) ligand in the aptamer domain regulates gene expression by inducing structural changes in another domain, the expression platform, causing transcription termination by the RNA polymerase. We have measured smFRET histograms over wide ranges of Mg2+ concentration for three RS variants that were specifically labeled with fluorescent dyes on different sites. In the analysis, different conformations are associated with discrete Gaussian model distributions, which are typically fairly broad on the FRET efficiency scale and thus can be extremely challenging to unravel due to their mutual overlap. Our earlier work on two SAM-I RS variants revealed four major conformations. By introducing a global fitting procedure which models both the Mg2+ concentration dependencies of the fractional populations and the average FRET efficiencies of the individual FRET distributions according to Mg2+ binding isotherms, we were able to consistently describe the histogram data of both variants at all studied Mg2+ concentrations. With the third FRET-labeled variant, however, we found significant deviations when applying the four-state model to the data. This can arise because the different FRET labeling of the new variant allows two states to be distinguished that were previously not separable due to overlap. Indeed, the resulting five-state model presented here consistently describes the smFRET histograms of all three variants as well as their variations with Mg2+ concentration. We also performed a triangulation of the donor position for two of the constructs

S-adenosylmethionine is associated with fat mass and truncal adiposity in older adults

NARCIS (Netherlands)

Elshorbagy, A.K.; Nijpels, G.; Valdivia-Garcia, M.; Stehouwer, C.D.; Ocke, M.; Refsum, H.; Dekker, J.M.

2013-01-01

S-adenosylmethionine (SAM) is synthesized from methionine, which is abundant in animal-derived protein, in an energyconsuming reaction. SAM and S-adenosylhomocysteine (SAH) correlate with body mass index (BMI). Plasma total concentration of the SAM-associated product cysteine (tCys) correlates with

Terpenoid Metabolism in Plastids 1

Science.gov (United States)

Camara, Bilal; Bardat, Françoise; Seye, Ababacar; D'Harlingue, Alain; Monéger, René

1982-01-01

The synthesis of α-tocopherol from 2,3-dimethylphytylquinol and S-adenosyl-l-methionine was achieved using Capsicum annuum fruit chromoplasts. The enzymes involved in the cyclization (2,3-dimethyl-phytylquinol cyclase) and methylation (S-adenosyl methionine:γ-tocopherol methyl-transferase) are both localized in the chromoplast membrane fraction (envelopes and/or a-chlorophyll lamellae), in contrast to the stroma fraction. PMID:16662717

Biosynthetic preparation of 35-S labelled methionine

International Nuclear Information System (INIS)

Freud, A.; Hirshfeld, N.; Teitelbaum, Z.; Heimer, Y.

1986-11-01

High specific activity methionine with sulfur-35 was prepared in our laboratory by growing Baker's yeast cells, in a medium containing 35 S-sulfate. L-S 35 methionine was prepared from the acid hydrolyzate of the proteins by chromatography on whatman paper. The specific activity was determined using o-phtaladehyde as a fluorophore to form a fluorescent complex. The specific activity was found to be usually greater than 800 Ci/mmol. (Author)

Effects of polyamine biosynthesis inhibitors on S-adenosylmethionine synthetase and S-adenosylmethionine decarboxylase activities in carrot cell cultures

Science.gov (United States)

S.C. Minocha; R. Minocha; A. Komamine

1991-01-01

Changes in the activites of S-adcnosylmethionine (SAM) synthetase (methionine adenosyltransferase, EC 2.5.1.6.) and SAM decarboxylase (EC 4.1.1.50) were studied in carrot (Daucus carota) cell cultures in response to 2,4-dichlorophenoxyacetic acid (2,4-D) and several inhibitors of polyamine biosynthesis. Activity of SAM synthetase increased...

Monolignol biosynthesis in microsomal preparations from lignifying stems of alfalfa (Medicago sativa L.).

Science.gov (United States)

Guo, Dianjing; Chen, Fang; Dixon, Richard A

2002-11-01

Microsomal preparations from lignifying stems of alfalfa (Medicago sativa L.) contained coniferaldehyde 5-hydroxylase activity and immunodetectable caffeic acid 3-O-methyltransferase (COMT), and catalyzed the S-adenosyl L-methionine (SAM) dependent methylation of caffeic acid, caffeyl aldehyde and caffeyl alcohol. When supplied with NADPH and SAM, the microsomes converted caffeyl aldehyde to coniferaldehyde, 5-hydroxyconiferaldehyde, and traces of sinapaldehyde. Coniferaldehyde was a better precursor of sinapaldehyde than was 5-hydroxyconiferaldehyde. The alfalfa microsomes could not metabolize 4-coumaric acid, 4-coumaraldehyde, 4-coumaroyl CoA, or ferulic acid. No metabolism of monolignol precursors was observed in microsomal preparations from transgenic alfalfa down-regulated in COMT expression. In most microsomal preparations, the level of the metabolic conversions was independent of added recombinant COMT. Taken together, the data provide only limited support for the concept of metabolic channeling in the biosynthesis of S monolignols via coniferaldehyde.

Structural Basis of Substrate Recognition in Thiopurine S-Methyltransferase

Energy Technology Data Exchange (ETDEWEB)

Peng, Yi; Feng, Qiping; Wilk, Dennis; Adjei, Araba A.; Salavaggione, Oreste E.; Weinshilboum, Richard M.; Yee, Vivien C. (Case Western); (MCCM)

2008-09-23

Thiopurine S-methyltransferase (TPMT) modulates the cytotoxic effects of thiopurine prodrugs such as 6-mercaptopurine by methylating them in a reaction using S-adenosyl-l-methionine as the donor. Patients with TPMT variant allozymes exhibit diminished levels of protein and/or enzyme activity and are at risk for thiopurine drug-induced toxicity. We have determined two crystal structures of murine TPMT, as a binary complex with the product S-adenosyl-l-homocysteine and as a ternary complex with S-adenosyl-l-homocysteine and the substrate 6-mercaptopurine, to 1.8 and 2.0 {angstrom} resolution, respectively. Comparison of the structures reveals that an active site loop becomes ordered upon 6-mercaptopurine binding. The positions of the two ligands are consistent with the expected S{sub N}2 reaction mechanism. Arg147 and Arg221, the only polar amino acids near 6-mercaptopurine, are highlighted as possible participants in substrate deprotonation. To probe whether these residues are important for catalysis, point mutants were prepared in the human enzyme. Substitution of Arg152 (Arg147 in murine TPMT) with glutamic acid decreases V{sub max} and increases K{sub m} for 6-mercaptopurine but not K{sub m} for S-adenosyl-l-methionine. Substitution at this position with alanine or histidine and similar substitutions of Arg226 (Arg221 in murine TPMT) result in no effect on enzyme activity. The double mutant Arg152Ala/Arg226Ala exhibits a decreased V{sub max} and increased K{sub m} for 6-mercaptopurine. These observations suggest that either Arg152 or Arg226 may participate in some fashion in the TPMT reaction, with one residue compensating when the other is altered, and that Arg152 may interact with substrate more directly than Arg226, consistent with observations in the murine TPMT crystal structure.

Independent Evolution of Six Families of Halogenating Enzymes.

Science.gov (United States)

Xu, Gangming; Wang, Bin-Gui

2016-01-01

Halogenated natural products are widespread in the environment, and the halogen atoms are typically vital to their bioactivities. Thus far, six families of halogenating enzymes have been identified: cofactor-free haloperoxidases (HPO), vanadium-dependent haloperoxidases (V-HPO), heme iron-dependent haloperoxidases (HI-HPO), non-heme iron-dependent halogenases (NI-HG), flavin-dependent halogenases (F-HG), and S-adenosyl-L-methionine (SAM)-dependent halogenases (S-HG). However, these halogenating enzymes with similar biological functions but distinct structures might have evolved independently. Phylogenetic and structural analyses suggest that the HPO, V-HPO, HI-HPO, NI-HG, F-HG, and S-HG enzyme families may have evolutionary relationships to the α/β hydrolases, acid phosphatases, peroxidases, chemotaxis phosphatases, oxidoreductases, and SAM hydroxide adenosyltransferases, respectively. These halogenating enzymes have established sequence homology, structural conservation, and mechanistic features within each family. Understanding the distinct evolutionary history of these halogenating enzymes will provide further insights into the study of their catalytic mechanisms and halogenation specificity.

Characterization of Timed Changes in Hepatic Copper Concentrations, Methionine Metabolism, Gene Expression, and Global DNA Methylation in the Jackson Toxic Milk Mouse Model of Wilson Disease

Directory of Open Access Journals (Sweden)

Anh Le

2014-05-01

Full Text Available Background: Wilson disease (WD is characterized by hepatic copper accumulation with progressive liver damage to cirrhosis. This study aimed to characterize the toxic milk mouse from The Jackson Laboratory (Bar Harbor, ME, USA (tx-j mouse model of WD according to changes over time in hepatic copper concentrations, methionine metabolism, global DNA methylation, and gene expression from gestational day 17 (fetal to adulthood (28 weeks. Methods: Included liver histology and relevant biochemical analyses including hepatic copper quantification, S-adenosylmethionine (SAM and S-adenosylhomocysteine (SAH liver levels, qPCR for transcript levels of genes relevant to methionine metabolism and liver damage, and DNA dot blot for global DNA methylation. Results: Hepatic copper was lower in tx-j fetuses but higher in weanling (three weeks and adult tx-j mice compared to controls. S-adenosylhomocysteinase transcript levels were significantly lower at all time points, except at three weeks, correlating negatively with copper levels and with consequent changes in the SAM:SAH methylation ratio and global DNA methylation. Conclusion: Compared to controls, methionine metabolism including S-adenosylhomocysteinase gene expression is persistently different in the tx-j mice with consequent alterations in global DNA methylation in more advanced stages of liver disease. The inhibitory effect of copper accumulation on S-adenosylhomocysteinase expression is associated with progressively abnormal methionine metabolism and decreased methylation capacity and DNA global methylation.

Mutagenic and Cytotoxic Properties of 6-Thioguanine, S6-Methylthioguanine, and Guanine-S6-sulfonic Acid*S⃞

OpenAIRE

Yuan, Bifeng; Wang, Yinsheng

2008-01-01

Thiopurine drugs, including 6-thioguanine (SG), 6-mercaptopurine, and azathioprine, are widely employed anticancer agents and immunosuppressants. The formation of SG nucleotides from the thiopurine prodrugs and their subsequent incorporation into nucleic acids are important for the drugs to exert their cytotoxic effects. SG in DNA can be methylated by S-adenosyl-l-methionine to give S6-methylthioguanine (S6mG) and oxidized by UVA light to render guanine-S6-sulfonic acid ...

Utilization of 35S methionine by the goat

International Nuclear Information System (INIS)

Champredon, C.; Pion, R.

1977-01-01

A mixture of 2.5 g of D,L-methionine and 2.1 mCi of L- 35 S methionine is injected into the rumen of two young dry goats. Abomasal contents and blood are sampled for 4 days after intraruminal injection of the tracer. Total radioactivity and specific activity of sulfur amino acids are measured in free- and protein-bound fractions of abomasal contents and blood. The radioactivity of the abomasal content soluble fraction (TCA) increases very rapidly. The main labelled compound in the TCA extract during the first hour is methionine. Total plasma radioactivity increases during the 9 hours following the injection, then decreases slowly. It is mainly found in the extract during the first hours of the experiment, but is almost totally recovered in the protein-bound fraction 48 hours after the injection. It is concluded that a part of the 35 S is absorbed directly from the rumen as unidentified sulfur-labelled compounds and is carried by the bloodstream, but a significant proportion of the 35 S introduced into the rumen as methionine is incorporated into microbial protein or enters the intestine directly [fr

Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger

OpenAIRE

Manzanares-Miralles, Lara; Bayram, Ozgur; Sarikaya-Bayram, Ozlem; Smith, Elizabeth B.; Dolan, Stephen K.; Jones, Gary W.; Doyle, Sean

2016-01-01

Gliotoxin (GT) is a redox-active metabolite, produced by Aspergillus fumigatus,which inhibits the growth of other fungi. Here we demonstrate how Aspergillus niger responds to GT exposure. Quantitative proteomics revealed that GT dysregulated the abundance of 378 proteins including those involved in methionine metabolism and induced de novo abundance of two S-adenosylmethionine (SAM)-dependent methyltransferases. Increased abundance of enzymes S-adenosylhomocysteinase (p = 0.0018) ...

Folate promotes S-adenosyl methionine reactions and the microbial methylation cycle and boosts ruminants production and reproduction.

Science.gov (United States)

Abbasi, Imtiaz Hussain Raja; Abbasi, Farzana; Wang, Lamei; Abd El Hack, Mohamed E; Swelum, Ayman A; Hao, Ren; Yao, Junhu; Cao, Yangchun

2018-04-23

Folate has gained significant attention due to its vital role in biological methylation and epigenetic machinery. Folate, or vitamin (B 9 ), is only produced through a de novo mechanism by plants and micro-organisms in the rumen of mature animals. Although limited research has been conducted on folate in ruminants, it has been noted that ruminal synthesis could not maintain folate levels in high yielding dairy animals. Folate has an essential role in one-carbon metabolism and is a strong antiproliferative agent. Folate increases DNA stability, being crucial for DNA synthesis and repair, the methylation cycle, and preventing oxidation of DNA by free radicals. Folate is also critical for cell division, metabolism of proteins, synthesis of purine and pyrimidine, and increasing the de novo delivery of methyl groups and S-adenosylmethionine. However, in ruminants, metabolism of B 12 and B 9 vitamins are closely connected and utilization of folate by cells is significantly affected by B 12 vitamin concentration. Supplementation of folate through diet, particularly in early lactation, enhanced metabolic efficiency, lactational performance, and nutritional quality of milk. Impaired absorption, oxidative degradation, or deficient supply of folate in ruminants affects DNA stability, cell division, homocysteine remethylation to methionine, de novo synthesis of S-adenosylmethionine, and increases DNA hypomethylation, uracil misincorporation into DNA, chromosomal damage, abnormal cell growth, oxidative species, premature birth, low calf weight, placental tube defects, and decreases production and reproduction of ruminant animals. However, more studies are needed to overcome these problems and reduce enormous dietary supplement waste and impaired absorption of folate in ruminants. This review was aimed to highlight the vital role of folic acid in ruminants performance.

S-Adenosyl-L-Methionine (SAMe): An Introduction

Science.gov (United States)

... the Science For Health Care Professionals Clinical Practice Guidelines Literature Reviews All Health Information Research Research Results ... rather than an oral form (taken by mouth). Osteoarthritis The results of research on SAMe for osteoarthritis ...

Gender differences in methionine accumulation and metabolism in freshly isolated mouse hepatocytes: Potential roles in toxicity

International Nuclear Information System (INIS)

Dever, Joseph T.; Elfarra, Adnan A.

2009-01-01

L-Methionine (Met) is hepatotoxic at high concentrations. Because Met toxicity in freshly isolated mouse hepatocytes is gender-dependent, the goal of this study was to assess the roles of Met accumulation and metabolism in the increased sensitivity of male hepatocytes to Met toxicity compared with female hepatocytes. Male hepatocytes incubated with Met (30 mM) at 37 o C exhibited higher levels of intracellular Met at 0.5, 1.0, and 1.5 h, respectively, compared to female hepatocytes. Conversely, female hepatocytes had higher levels of S-adenosyl-L-methionine compared to male hepatocytes. Female hepatocytes also exhibited higher L-methionine-L-sulfoxide levels relative to control hepatocytes, whereas the increases in L-methionine-D-sulfoxide (Met-D-O) levels were similar in hepatocytes of both genders. Addition of aminooxyacetic acid (AOAA), an inhibitor of Met transamination, significantly increased Met levels at 1.5 h and increased Met-D-O levels at 1.0 and 1.5 h only in Met-exposed male hepatocytes. No gender differences in cytosolic Met transamination activity by glutamine transaminase K were detected. However, female mouse liver cytosol exhibited higher methionine-DL-sulfoxide (MetO) reductase activity than male mouse liver cytosol at low (0.25 and 0.5 mM) MetO concentrations. Collectively, these results suggest that increased cellular Met accumulation, decreased Met transmethylation, and increased Met and MetO transamination in male mouse hepatocytes may be contributing to the higher sensitivity of the male mouse hepatocytes to Met toxicity in comparison with female mouse hepatocytes.

Modification of -Adenosyl--Homocysteine as Inhibitor of Nonstructural Protein 5 Methyltransferase Dengue Virus Through Molecular Docking and Molecular Dynamics Simulation

Directory of Open Access Journals (Sweden)

Usman Sumo Friend Tambunan

2017-04-01

Full Text Available Dengue fever is still a major threat worldwide, approximately threatening two-fifths of the world’s population in tropical and subtropical countries. Nonstructural protein 5 (NS5 methyltransferase enzyme plays a vital role in the process of messenger RNA capping of dengue by transferring methyl groups from S -adenosyl- l -methionine to N7 atom of the guanine bases of RNA and the RNA ribose group of 2′OH, resulting in S -adenosyl- l -homocysteine (SAH. The modification of SAH compound was screened using molecular docking and molecular dynamics simulation, along with computational ADME-Tox (absorption, distribution, metabolism, excretion, and toxicity test. The 2 simulations were performed using Molecular Operating Environment (MOE 2008.10 software, whereas the ADME-Tox test was performed using various software. The modification of SAH compound was done using several functional groups that possess different polarities and properties, resulting in 3460 ligands to be docked. After conducting docking simulation, we earned 3 best ligands (SAH-M331, SAH-M2696, and SAH-M1356 based on ΔG binding and molecular interactions, which show better results than the standard ligands. Moreover, the results of molecular dynamics simulation show that the best ligands are still able to maintain the active site residue interaction with the binding site until the end of the simulation. After a series of molecular docking and molecular dynamics simulation were performed, we concluded that SAH-M1356 ligand is the most potential SAH-based compound to inhibit NS5 methyltransferase enzyme for treating dengue fever.

In Vitro Optimization of Enzymes Involved in Precorrin-2 Synthesis Using Response Surface Methodology.

Science.gov (United States)

Fang, Huan; Dong, Huina; Cai, Tao; Zheng, Ping; Li, Haixing; Zhang, Dawei; Sun, Jibin

2016-01-01

In order to maximize the production of biologically-derived chemicals, kinetic analyses are first necessary for predicting the role of enzyme components and coordinating enzymes in the same reaction system. Precorrin-2 is a key precursor of cobalamin and siroheme synthesis. In this study, we sought to optimize the concentrations of several molecules involved in precorrin-2 synthesis in vitro: porphobilinogen synthase (PBGS), porphobilinogen deaminase (PBGD), uroporphyrinogen III synthase (UROS), and S-adenosyl-l-methionine-dependent urogen III methyltransferase (SUMT). Response surface methodology was applied to develop a kinetic model designed to maximize precorrin-2 productivity. The optimal molar ratios of PBGS, PBGD, UROS, and SUMT were found to be approximately 1:7:7:34, respectively. Maximum precorrin-2 production was achieved at 0.1966 ± 0.0028 μM/min, agreeing with the kinetic model's predicted value of 0.1950 μM/min. The optimal concentrations of the cofactor S-adenosyl-L-methionine (SAM) and substrate 5-aminolevulinic acid (ALA) were also determined to be 200 μM and 5 mM, respectively, in a tandem-enzyme assay. By optimizing the relative concentrations of these enzymes, we were able to minimize the effects of substrate inhibition and feedback inhibition by S-adenosylhomocysteine on SUMT and thereby increase the production of precorrin-2 by approximately five-fold. These results demonstrate the effectiveness of kinetic modeling via response surface methodology for maximizing the production of biologically-derived chemicals.

A novel double-isotope technique for the enzymatic assay of plasma histamine: application to estimation of mast cell activation assessed by antigen challenge in asthmatics

International Nuclear Information System (INIS)

Brown, M.J.; Ind, P.W.; Causon, R.; Lee, T.H.

1982-01-01

The concentration of plasma histamine may provide an index of mast cell activation (degranulation) and can be measured by a sensitive radioenzymatic assay based on its specific conversion to (/sup 3/H)-methylhistamine in the presence of histamine-N-methyltransferase and (/sup 3/H)-S-adenosyl-L-methionine. In this assay, the separation of excess (/sup 3/H)-S-adenosyl-L-methionine from (/sup 3/H)-methylhistamine requires several steps, for which a correction factors is necessary to maintain precision. In the present modification, duplicate 50-microliters aliquots of each plasma sample were incubated with histamine-N-methyltransferase and (/sup 3/H)-S-adenosyl-L-methionine. A further aliquot, with an added standard of 200 ng/ml histamine, was incubated with histamine-N-methyl-transferase and (/sup 14/C)-S-adenosyl-L-methionine. This standard was converted to (/sup 14/C)-methylhistamine, and its recovery at the end of the assay corrected both for varying efficiency of methylation among plasma samples and for losses during the subsequent extraction and separation stages. The sensitivity of the assay was 25 pg/ml. The intra-assay and interassay coefficients of variation were 7.2% and 11.6%, respectively. In five asthmatics, antigen challenge caused a 28% fall in FEV1, and this was associated with a twofold to threefold rise in plasma histamine concentration. This assay may thus prove a useful method for assessing the role of mast cell release of mediators in vivo

Polyamine metabolism in the kidneys of castrated and testosterone-treated mice after administration of methylglyoxal bis(guanylhydrazone).

Science.gov (United States)

Henningsson, S; Persson, L; Rosengren, E

1979-02-01

The effects of methylglyoxal bis(guanylhydrazone) on S-adenosyl-L-methionine decarboxylase (EC 4.1.1.50) activity were studied in the mouse kidney stimulated to growth by testosterone administration. The drug was found a potent inhibitor of the enzyme in vitrol Administration of methylglyoxal bis(guanylhydrazone) in vivo resulted in a transient inhibition followed by a strong enhancement of the enzyme activity. Dialysis of the kidney extract, to remove remaining methylglyoxal bis(guanylhydrazone), revealed a great and rapid increase in the activity of S-adenosyl-L-methionine decarboxylase. Injections of testosterone to castrated mice resulted in a marked increase in kidney weight and an accumulation of renal putrescine, spermidine and spermine. These effects of testosterone could not be blocked by simultaneous injections of methylglyoxal bis(guanylhydrazone). It appears that due to secondary effects by which the inhibition of methylglyoxal bis(guanylhydrazone) on S-adenosyl-L-methionine decarboxylase activity is circumvented the inhibitor seems to be of uncertain value in attempts to decrease selectively the in vivo levels of polyamines.

S-adenosylmethionine decarboxylase from baker's yeast.

Science.gov (United States)

Pösö, H; Sinervirta, R; Jänne, J

1975-01-01

1. S-Adenosyl-L-methionine decarboxylase (S-adenosyl-L-methionine carboxy-lyase, EC 4.1.1.50) was purified more than 1100-fold from extracts of Saccharomyces cerevisiae by affinity chromatography on columns of Sepharose containing covalently bound methylglyoxal bis(guanylhydrazone) (1,1'[(methylethanediylidene)dinitrilo]diguanidine) [Pegg, (1974) Biochem J. 141, 581-583]. The final preparation appeared to be homogeneous on polyacrylamide-gel electrophoresis at pH 8.4. 2. S-Adenosylmethionine decarboxylase activity was completely separated from spermidine synthase activity [5'-deoxyadenosyl-(5'),3-aminopropyl-(1),methylsulphonium-salt-putrescine 3-aminopropyltransferase, EC 2.5.1.16] during the purification procedure. 3. Adenosylmethionine decarboxylase activity from crude extracts of baker's yeast was stimulated by putrescine, 1,3-diamino-propane, cadaverine (1,5-diaminopentane) and spermidine; however, the purified enzyme, although still stimulated by the diamines, was completely insensitive to spermidine. 4. Adenosylmethionine decarboxylase has an apparent Km value of 0.09 mM for adenosylmethionine in the presence of saturating concentrations of putrescine. The omission of putrescine resulted in a five-fold increase in the apparent Km value for adenosylmethionine. 5. The apparent Ka value for putrescine, as the activator of the reaction, was 0.012 mM. 6. Methylglyoxal bis(guanylhydrazone) and S-methyladenosylhomocysteamine (decarboxylated adenosylmethionine) were powerful inhibitors of the enzyme. 7. Adenosylmethionine decarboxylase from baker's yeast was inhibited by a number of conventional carbonyl reagents, but in no case could the inhibition be reversed with exogenous pyridoxal 5'-phosphate. PMID:1108876

SAM Photovoltaic Model Technical Reference

Energy Technology Data Exchange (ETDEWEB)

Gilman, P. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2015-05-27

This manual describes the photovoltaic performance model in the System Advisor Model (SAM). The U.S. Department of Energy’s National Renewable Energy Laboratory maintains and distributes SAM, which is available as a free download from https://sam.nrel.gov. These descriptions are based on SAM 2015.1.30 (SSC 41).

Radiation stability of methionine-35S and selenomethionine-75Se

International Nuclear Information System (INIS)

Galateanu, I.; Lungu, V.V.; Viorel, D.

1976-01-01

The radiation stability of methionine- 35 S and selenomethionine 75 Se was investigated using the methods of thin-layer chromatography, gas chromatography and ESR. Radiation decomposition of methionine- 35 S mainly consists in an oxidation process and in the release of volatile products. The ESR-spectra of irradiated DL-methionine indicated a strong localization of the unpaired electrons on sulfur atoms. Radiation damage to selenomethionine- 75 Se as a function of radiation dose proved an increased stability of this compound and its radiation decomposition consists in the formation of oxidized products and by direct rupture of the selenium bounds accompanied by the formation of volatile compounds like CH 3 SEH and SeH 2 . The self-radiolysis of the aqueous solution of selenomethionine- 75 Se during its storage in air leads, however, to a lower decomposition rate which consists in the release of inorganic selenium and in an oxidation process. (author)

Inhibition of thiopurine S-methyltransferase activity by impurities in commercially available substrates: a factor for differing results of TPMT measurements.

Science.gov (United States)

Kröplin, T; Fischer, C; Iven, H

1999-06-01

Thiopurine S-methyltransferase (TPMT) activity, when measured in red blood cells (RBC) with a recently published TPMT activity assay using 6-thioguanine (6-TG) as substrate, could not be reproduced in another laboratory. We investigated factors which could influence the results of the TPMT activity measurement. We tested twelve 6-TG and four 6-mercaptopurine (6-MP) compounds from different suppliers as substrates and determined the enzyme kinetic parameters Km and Vmax. Furthermore, we studied the influence of different 6-TG compounds on the affinity of the methyl donor S-adenosyl-L-methionine (SAM) to the TPMT enzyme. All 6-TG products were of equal purity (declared >98% by the supplier): this was ascertained by HPLC. However, the rate of methylation obtained following incubation with 6-TG from different suppliers ranged from 10% to 100% when incubated with the same RBC lysate. The lowest apparent Km value for a 6-TG was 22.3 micromol x l(-1), while the product with the highest methylation rate showed a Km of 156 micromol x l(-1). From these results we assume that there is a contaminant in some 6-TG products, which acts as a strong inhibitor of TPMT activity. Compounds possibly used for the synthesis of 6-TG (guanine, pyridine, 6-chloroguanine) did not affect the methylation rate. Thioxanthine, which is known to be a strong inhibitor of TPMT when added to the assay system to give a 2% contamination, reduced TPMT activity from 100% to 72%. Using 6-MP from different suppliers as substrate resulted in Km values ranging from 110 to 162 micromol x l(-1) and Vmox values ranging from 54 to 68 nmol 6-MMP x g(-1)Hb x h(-1). The Km value for the methyl donor SAM was similar to and independent from the thiopurine substrates tested (range 4.9-11 micromol-l(-1) SAM). In contrast to other investigators, we found non-enzymatic S-methylation, which was negligible under our assay conditions (3% with 128 micromol x l(-1) SAM), but could become relevant in experiments using higher

Proteomic Analysis of Stationary Phase in the Marine Bacterium "Candidatus Pelagibacter ubique"

Energy Technology Data Exchange (ETDEWEB)

Sowell, S. M.; Norbeck, A. D.; Lipton, M. S.; Nicora, C. D.; Callister, S. J.; Smith, R. D.; Barofsky, D. F.; Giovannoni, S. J.

2008-05-09

The α-proteobacterium ‘Candidatus Pelagibacter ubique’ str. HTCC1062, and most other members of the SAR11 clade, lack genes for assimilatory sulfate reduction, making them dependent on organosulfur compounds that occur naturally in seawater. To investigate how these cells adapt to sulfur limitation, batch cultures were grown in defined media containing either limiting or non-limiting amounts of dimethylsulfoniopropionate (DMSP) as the sole sulfur source. Protein and mRNA expression were measured during exponential growth, immediately prior to stationary phase, and in late stationary phase. Two distinct responses were observed: one as DMSP became exhausted, and another as cells acclimated to a sulfur-limited environment. The first response was characterized by increased transcription and translation of all Ca. P. ubique genes downstream of previously confirmed S-adenosyl methionine (SAM) riboswitches: bhmT, mmuM, and metY. Proteins encoded by these genes were up to 33 times more abundant as DMSP became limiting. Their predicted function is to shunt all available sulfur to methionine. The secondary response, observed during sulfur-depleted stationary phase, was a 6-10 fold increase in transcription of the heme c shuttle ccmC and two small genes of unknown function (SAR11_1163 and SAR11_1164). This bacterium's strategy for coping with sulfur stress appears to be intracellular redistribution to support methionine biosynthesis, rather than increasing organosulfur import. Many of the genes and SAM riboswitches involved in this response are located in a hypervariable genome region (HVR). One of these HVR genes, ordL, is located downstream of a conserved motif that evidence suggests is a novel riboswitch.

Evolution of the key alkaloid enzyme putrescine N-methyltransferase from spermidine synthase.

Directory of Open Access Journals (Sweden)

Anne eJunker

2013-07-01

Full Text Available Putrescine N-methyltransferases (PMTs are the first specific enzymes of the biosynthesis of nicotine and tropane alkaloids. PMTs transfer a methyl group onto the diamine putrescine from S-adenosyl-L-methionine (SAM as coenzyme. PMT proteins have presumably evolved from spermidine synthases (SPDSs, which are ubiquitous enzymes of polyamine metabolism. SPDS use decarboxylated SAM as coenzyme to transfer an aminopropyl group onto putrescine. In an attempt to identify possible and necessary steps in the evolution of PMT from SPDS, homology based modeling of Datura stramonium SPDS1 and PMT was employed to gain deeper insight in the preferred binding positions and conformations of the substrate and the alternative coenzymes. Based on predictions of amino acids responsible for the change of enzyme specificities, sites of mutagenesis were derived. PMT activity was generated in Datura stramonium SPDS1 after few amino acid exchanges. Concordantly, Arabidopsis thaliana SPDS1 was mutated and yielded enzymes with both, PMT and SPDS activities. Kinetic parameters were measured for enzymatic characterization. The switch from aminopropyl to methyl transfer depends on conformational changes of the methionine part of the coenzyme in the binding cavity of the enzyme. The rapid generation of PMT activity in SPDS proteins and the wide-spread occurrence of putative products of N-methylputrescine suggest that PMT activity is present frequently in the plant kingdom.

The relative contribution of genes operating in the S-methylmethionine cycle to methionine metabolism in Arabidopsis seeds.

Science.gov (United States)

Cohen, Hagai; Salmon, Asaf; Tietel, Zipora; Hacham, Yael; Amir, Rachel

2017-05-01

Enzymes operating in the S -methylmethionine cycle make a differential contribution to methionine synthesis in seeds. In addition, mutual effects exist between the S -methylmethionine cycle and the aspartate family pathway in seeds. Methionine, a sulfur-containing amino acid, is a key metabolite in plant cells. The previous lines of evidence proposed that the S-methylmethionine (SMM) cycle contributes to methionine synthesis in seeds where methionine that is produced in non-seed tissues is converted to SMM and then transported via the phloem into the seeds. However, the relative regulatory roles of the S-methyltransferases operating within this cycle in seeds are yet to be fully understood. In the current study, we generated transgenic Arabidopsis seeds with altered expression of three HOMOCYSTEINE S-METHYLTRANSFERASEs (HMTs) and METHIONINE S-METHYLTRANSFERASE (MMT), and profiled them for transcript and metabolic changes. The results revealed that AtHMT1 and AtHMT3, but not AtHMT2 and AtMMT, are the predominant enzymes operating in seeds as altered expression of these two genes affected the levels of methionine and SMM in transgenic seeds. Their manipulations resulted in adapted expression level of genes participating in methionine synthesis through the SMM and aspartate family pathways. Taken together, our findings provide new insights into the regulatory roles of the SMM cycle and the mutual effects existing between the two methionine biosynthesis pathways, highlighting the complexity of the metabolism of methionine and SMM in seeds.

Two Distinct Aerobic Methionine Salvage Pathways Generate Volatile Methanethiol in Rhodopseudomonas palustris

Science.gov (United States)

Miller, Anthony R.; North, Justin A.; Wildenthal, John A.

2018-01-01

ABSTRACT 5′-Methyl-thioadenosine (MTA) is a dead-end, sulfur-containing metabolite and cellular inhibitor that arises from S-adenosyl-l-methionine-dependent reactions. Recent studies have indicated that there are diverse bacterial methionine salvage pathways (MSPs) for MTA detoxification and sulfur salvage. Here, via a combination of gene deletions and directed metabolite detection studies, we report that under aerobic conditions the facultatively anaerobic bacterium Rhodopseudomonas palustris employs both an MTA-isoprenoid shunt identical to that previously described in Rhodospirillum rubrum and a second novel MSP, both of which generate a methanethiol intermediate. The additional R. palustris aerobic MSP, a dihydroxyacetone phosphate (DHAP)-methanethiol shunt, initially converts MTA to 2-(methylthio)ethanol and DHAP. This is identical to the initial steps of the recently reported anaerobic ethylene-forming MSP, the DHAP-ethylene shunt. The aerobic DHAP-methanethiol shunt then further metabolizes 2-(methylthio)ethanol to methanethiol, which can be directly utilized by O-acetyl-l-homoserine sulfhydrylase to regenerate methionine. This is in contrast to the anaerobic DHAP-ethylene shunt, which metabolizes 2-(methylthio)ethanol to ethylene and an unknown organo-sulfur intermediate, revealing functional diversity in MSPs utilizing a 2-(methylthio)ethanol intermediate. When MTA was fed to aerobically growing cells, the rate of volatile methanethiol release was constant irrespective of the presence of sulfate, suggesting a general housekeeping function for these MSPs up through the methanethiol production step. Methanethiol and dimethyl sulfide (DMS), two of the most important compounds of the global sulfur cycle, appear to arise not only from marine ecosystems but from terrestrial ones as well. These results reveal a possible route by which methanethiol might be biologically produced in soil and freshwater environments. PMID:29636438

Suppression of TNF-alpha production by S-adenosylmethionine in human mononuclear leukocytes is not mediated by polyamines

DEFF Research Database (Denmark)

Yu, J.; Parlesak, Alexandr; Sauter, S.

2006-01-01

precursors or metabolites [phosphatidylcholine, choline, betaine, S-adenosylmethionine (SAM)] have a modulating effect on tumor necrosis factor alpha (TNF-alpha) production by endotoxin-stimulated human mononuclear leukocytes and whether SAM-dependent polyamines (spermidine, spermine) are mediators of SAM......-induced inhibition of TNF-alpha synthesis. Methionine and betaine had a moderate stimulatory effect on TNF-alpha production, whereas phosphatidylcholine (ID(50) 5.4 mM), SAM (ID(50) 131 microM), spermidine (ID(50) 4.5 microM) and spermine (ID(50) 3.9 microM) had a predominantly inhibitory effect. Putrescine did...

Methionine metabolism after portacaval shunt in the rat

International Nuclear Information System (INIS)

Benjamin, L.E.; Steele, R.D.

1985-01-01

The effect of portacaval shunt (PCS) on methionine metabolism in the rat was investigated. Male Sprague-Dawley rats were subjected to PCS and maintained on an 18% casein diet. Growth curves of operated rats were similar to controls. PCS rats excreted more urinary 35 SO 4 and less [ 35 S]taurine than controls after intraperitoneal injection of 0.3 mmol/100 g [ 35 S]methionine or [ 35 S]cysteine. Total urinary taurine excretion was similar in PCS and control rats after a methionine or cysteine load; however, under basal conditions PCS rats had higher urinary taurine levels than controls, indicating that PCS may cause the taurine pool to be expanded. Hepatic methionine, S-adenosylmethionine, and cysteine pools were significantly decreased in PCS rats, while S-adenosylhomocysteine levels were unchanged. Relative rates of transsulfuration in PCS and control rats were studied by following the decrease in the 3 H-to- 35 S ratio in liver protein after injection of [methyl-3H]methionine and [ 35 S]methionine, and no difference in flux of 35 S from [ 35 S]methionine to [ 35 S]cysteine was found. Similarly, total hepatic activities of methionine adenosyltransferase, cystathionine synthase, and cystathionine gamma-lyase were unchanged in PCS rats. These results indicate that altered methionine metabolism in PCS rats is not explained by changes in conversion of methionine to cysteine via the transsulfuration pathway

Parameters of the labeling of mitogen-activated murine lymphocytes by [35S]methionine for two-dimensional gel electrophoresis. I

International Nuclear Information System (INIS)

Kettman, J.R.

1986-01-01

Labeling with [ 35 S]methionine at a high specific activity is essential to the facile preparation of 2-dimensional gel electrophoretograms with the analytical 2-dimensional charge-size separation procedure. Mitogen-activated T and B lymphocytes subjected to low methionine concentrations would not proceed through cell cycle. In the case of activated B lymphocytes, the use of fetal bovine serum, dialyzed to lower endogenous methionine concentrations, prevented B cell growth even in the presence of otherwise satisfactory levels of methionine. High concentrations of [ 35 S]methionine induced B cell death, apparently by radiation damage. Despite these problems, good radioautograms and radiofluorograms of 2D electrophoretograms could be prepared by labeling activated B or T cells in bulk with high specific activity [ 35 S]methionine. (Auth.)

Impact of folic acid intake during pregnancy on genomic imprinting of IGF2/H19 and 1-carbon metabolism.

Science.gov (United States)

Tserga, Aggeliki; Binder, Alexandra M; Michels, Karin B

2017-12-01

Folic acid is an essential component of 1-carbon metabolism, which generates methyl groups for DNA methylation. Disruption of genomic imprinting leads to biallelic expression which may affect disease susceptibility possibly reflected in high levels of S -adenosyl-homocysteine (SAH) and low levels of S -adenosyl-methionine (SAM). We investigated the association between folic acid supplementation during pregnancy and loss of imprinting (LOI) of IGF2 and H19 genes in placentas and cord blood of 90 mother-child dyads in association with the methylenetetrahydrofolate reductase ( MTHFR ) genotype. Pyrosequencing was used to evaluate deviation from monoallelic expression among 47 placentas heterozygous for H19 and 37 placentas and cord blood tissues heterozygous for IGF2 and H19 methylation levels of 48 placentas. We detected relaxation of imprinting (ROI) and LOI of H19 in placentas not associated with differences in methylation levels of the H19ICR. Placentas retained monoallelic allele-specific gene expression of IGF2 , but 32.4% of cord blood samples displayed LOI of IGF2 and 10.8% showed ROI. High SAH levels were significantly associated with low H19 methylation. An interesting positive association between SAM/SAH ratio and high H19 methylation levels was detected among infants with low B 12 levels. Our data suggest profound differences in regulation of imprinting in placenta and cord blood; a lack of correlation of the methylome, transcriptome, and proteome; and a complex regulatory feedback network between free methyl groups and genomic imprinting at birth.-Tserga, A., Binder, A. M., Michels, K. B. Impact of folic acid intake during pregnancy on genomic imprinting of IGF2/H19 and 1-carbon metabolism. © FASEB.

Enzymatic methylation of band 3 anion transporter in intact human erythrocytes

International Nuclear Information System (INIS)

Lou, L.L.; Clarke, S.

1987-01-01

Band 3, the anion transport protein of erythrocyte membranes, is a major methyl-accepting substrate of the intracellular erythrocyte protein carboxyl methyltransferase (S-adenosyl-L-methionine: protein-D-aspartate O-methyltransferase; EC 2.1.1.77). The localization of methylation sites in intact cells by analysis of proteolytic fragments indicated that sites were present in the cytoplasmic N-terminal domain as well as the membranous C-terminal portion of the polypeptide. The amino acid residues that serve as carboxyl methylation sites of the erythrocyte anion transporter were also investigated. 3 H-Methylated band 3 was purified from intact erythrocytes incubated with L-[methyl- 3 H]methionine and from trypsinized and lysed erythrocytes incubated with S-adenosyl-L-[methyl- 3 H]methionine. After proteolytic digestion with carboxypeptidase Y, D-aspartic acid beta-[ 3 H]methyl ester was isolated in low yields (9% and 1%, respectively) from each preparation. The bulk of the radioactivity was recovered as [ 3 H]methanol, and the amino acid residue(s) originally associated with these methyl groups could not be determined. No L-aspartic acid beta-[ 3 H]methyl ester or glutamyl gamma-[ 3 H]methyl ester was detected. The formation of D-aspartic acid beta-[ 3 H]methyl esters in this protein in intact cells resulted from protein carboxyl methyltransferase activity since it was inhibited by adenosine and homocysteine thiolactone, which increases the intracellular concentration of the potent product inhibitor S-adenosylhomocysteine, and cycloleucine, which prevents the formation of the substrate S-adenosyl-L-[methyl- 3 H]methionine

A disulfide-stabilized conformer of methionine synthase reveals an unexpected role for the histidine ligand of the cobalamin cofactor

Energy Technology Data Exchange (ETDEWEB)

Datta, Supratim; Koutmos, Markos; Pattridge, Katherine A.; Ludwig, Martha L.; Matthews, Rowena G. (Michigan)

2008-07-08

B{sub 12}-dependent methionine synthase (MetH) from Escherichia coli is a large modular protein that is alternately methylated by methyltetrahydrofolate to form methylcobalamin and demethylated by homocysteine to form cob(I)alamin. Major domain rearrangements are required to allow cobalamin to react with three different substrates: homocysteine, methyltetrahydrofolate, and S-adenosyl-l-methionine (AdoMet). These same rearrangements appear to preclude crystallization of the wild-type enzyme. Disulfide cross-linking was used to lock a C-terminal fragment of the enzyme into a unique conformation. Cysteine point mutations were introduced at Ile-690 and Gly-743. These cysteine residues span the cap and the cobalamin-binding module and form a cross-link that reduces the conformational space accessed by the enzyme, facilitating protein crystallization. Here, we describe an x-ray structure of the mutant fragment in the reactivation conformation; this conformation enables the transfer of a methyl group from AdoMet to the cobalamin cofactor. In the structure, the axial ligand to the cobalamin, His-759, dissociates from the cobalamin and forms intermodular contacts with residues in the AdoMet-binding module. This unanticipated intermodular interaction is expected to play a major role in controlling the distribution of conformers required for the catalytic and the reactivation cycles of the enzyme.

Preliminary characterization of (nucleoside-2′-O-)-methyltransferase crystals from Meaban and Yokose flaviviruses

International Nuclear Information System (INIS)

Mastrangelo, Eloise; Bollati, Michela; Milani, Mario; Lamballeire, Xavier de; Brisbare, Nadege; Dalle, Karen; Lantez, Violaine; Egloff, Marie-Pierre; Coutard, Bruno; Canard, Bruno; Gould, Ernest; Forrester, Naomi; Bolognesi, Martino

2006-01-01

Two methyltransferases from flaviviruses (Meaban and Yokose viruses) have been overexpressed and crystallized. Diffraction data and characterization of the two crystal forms are presented, together with a preliminary molecular-replacement solution for both enzymes. Viral methyltranferases (MTase) are involved in the third step of the mRNA-capping process, transferring a methyl group from S-adenosyl-l-methionine (SAM) to the capped mRNA. MTases are classified into two groups: (guanine-N7)-methyltransferases (N7MTases), which add a methyl group onto the N7 atom of guanine, and (nucleoside-2′-O-)-methyltransferases (2′OMTases), which add a methyl group to a ribose hydroxyl. The MTases of two flaviviruses, Meaban and Yokose viruses, have been overexpressed, purified and crystallized in complex with SAM. Characterization of the crystals together with details of preliminary X-ray diffraction data collection (at 2.8 and 2.7 Å resolution, respectively) are reported here. The sequence homology relative to Dengue virus 2′OMTase and the structural conservation of specific residues in the putative active sites suggest that both enzymes belong to the 2′OMTase subgroup

High-performance liquid chromatographic radioenzymatic assay for plasma catecyholamines

International Nuclear Information System (INIS)

Klaniecki, T.S.; Corder, C.N.; McDonald, R.H. Jr.; Feldman, J.A.

1977-01-01

A new assay method for plasma catecholamimes (CA) requiring only 50 μl has been developed, which uses high performance liquid chromatography (HPLC). The norepinephrine (NE), dopamine (D), and epinephrine (E) compounds found in plasma are radioactively o-methylated with S-[methyl- 3 H]-adenosyl-L-methionine ( 3 H-SAM) 3 H-SAM by the reaction of catechol-o-methyl transferase (COMT). The reaction is terminated and a standard mixture of nonradioactive o-methylated analogues of NE, D, and E is added to act as a carrier. Following separation by HPLC, the D,L-normetanephrine (NMN), 3-methoxy-4-hydroxyphenylethyl-amine or 3-methoxytyramine (3-MOT), and metanephrine (MN) radioactive peaks are collected which represent NE, D, and E, respectively. Then MNM and MN are oxidized to vanillin, and 3-MOT is acetylated. The products are subsequently separated by solvent extraction. This is necessary in order to avoid high radioactive blanks and to allow quantitation of the radioactivity by liquid scintillation spectrometry. The mean supine levels of NE, D, and E in normal subjects were respectively 182, 33, and 87 pg/ml of plasma. Similar assays on patients with pheochromocytoma revealed 797, 80, and 470 pg/ml

Biochemical research elucidating metabolic pathways in Pneumocystis*

Directory of Open Access Journals (Sweden)

Kaneshiro E.S.

2010-12-01

Full Text Available Advances in sequencing the Pneumocystis carinii genome have helped identify potential metabolic pathways operative in the organism. Also, data from characterizing the biochemical and physiological nature of these organisms now allow elucidation of metabolic pathways as well as pose new challenges and questions that require additional experiments. These experiments are being performed despite the difficulty in doing experiments directly on this pathogen that has yet to be subcultured indefinitely and produce mass numbers of cells in vitro. This article reviews biochemical approaches that have provided insights into several Pneumocystis metabolic pathways. It focuses on 1 S-adenosyl-L-methionine (AdoMet; SAM, which is a ubiquitous participant in numerous cellular reactions; 2 sterols: focusing on oxidosqualene cyclase that forms lanosterol in P. carinii; SAM:sterol C-24 methyltransferase that adds methyl groups at the C-24 position of the sterol side chain; and sterol 14α-demethylase that removes a methyl group at the C-14 position of the sterol nucleus; and 3 synthesis of ubiquinone homologs, which play a pivotal role in mitochondrial inner membrane and other cellular membrane electron transport.

Preliminary characterization of (nucleoside-2′-O-)-methyltransferase crystals from Meaban and Yokose flaviviruses

Energy Technology Data Exchange (ETDEWEB)

Mastrangelo, Eloise; Bollati, Michela; Milani, Mario [Department of Biomolecular Sciences and Biotechnology, CNR-INFM, University of Milano, Via Celoria 26, 20133 Milano (Italy); Lamballeire, Xavier de; Brisbare, Nadege [Unité des Virus Emergents, Faculté de Médecine, 27 Boulevard Jean Moulin, 13005 Marseille (France); Dalle, Karen; Lantez, Violaine; Egloff, Marie-Pierre; Coutard, Bruno; Canard, Bruno [Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 6098 CNRS ESIL, Case 932, 163 Avenue de Luminy, 13288 Marseille CEDEX 9 (France); Gould, Ernest; Forrester, Naomi [CEH Oxford, Mansfield Road, Oxford OX1 3SR (United Kingdom); Bolognesi, Martino, E-mail: martino.bolognesi@unimi.it [Department of Biomolecular Sciences and Biotechnology, CNR-INFM, University of Milano, Via Celoria 26, 20133 Milano (Italy)

2006-08-01

Two methyltransferases from flaviviruses (Meaban and Yokose viruses) have been overexpressed and crystallized. Diffraction data and characterization of the two crystal forms are presented, together with a preliminary molecular-replacement solution for both enzymes. Viral methyltranferases (MTase) are involved in the third step of the mRNA-capping process, transferring a methyl group from S-adenosyl-l-methionine (SAM) to the capped mRNA. MTases are classified into two groups: (guanine-N7)-methyltransferases (N7MTases), which add a methyl group onto the N7 atom of guanine, and (nucleoside-2′-O-)-methyltransferases (2′OMTases), which add a methyl group to a ribose hydroxyl. The MTases of two flaviviruses, Meaban and Yokose viruses, have been overexpressed, purified and crystallized in complex with SAM. Characterization of the crystals together with details of preliminary X-ray diffraction data collection (at 2.8 and 2.7 Å resolution, respectively) are reported here. The sequence homology relative to Dengue virus 2′OMTase and the structural conservation of specific residues in the putative active sites suggest that both enzymes belong to the 2′OMTase subgroup.

Production of FAME biodiesel in E. coli by direct methylation with an insect enzyme.

Science.gov (United States)

Sherkhanov, Saken; Korman, Tyler P; Clarke, Steven G; Bowie, James U

2016-04-07

Most biodiesel currently in use consists of fatty acid methyl esters (FAMEs) produced by transesterification of plant oils with methanol. To reduce competition with food supplies, it would be desirable to directly produce biodiesel in microorganisms. To date, the most effective pathway for the production of biodiesel in bacteria yields fatty acid ethyl esters (FAEEs) at up to ~1.5 g/L. A much simpler route to biodiesel produces FAMEs by direct S-adenosyl-L-methionine (SAM) dependent methylation of free fatty acids, but FAME production by this route has been limited to only ~16 mg/L. Here we employ an alternative, broad spectrum methyltransferase, Drosophila melanogaster Juvenile Hormone Acid O-Methyltransferase (DmJHAMT). By introducing DmJHAMT in E. coli engineered to produce medium chain fatty acids and overproduce SAM, we obtain medium chain FAMEs at titers of 0.56 g/L, a 35-fold increase over titers previously achieved. Although considerable improvements will be needed for viable bacterial production of FAMEs and FAEEs for biofuels, it may be easier to optimize and transport the FAME production pathway to other microorganisms because it involves fewer enzymes.

Intra-mitochondrial Methylation Deficiency Due to Mutations in SLC25A26

NARCIS (Netherlands)

Kishita, Y.; Pajak, A.; Bolar, N.A.; Marobbio, C.M.; Maffezzini, C.; Miniero, D.V.; Monne, M.; Kohda, M.; Stranneheim, H.; Murayama, K.; Naess, K.; Lesko, N.; Bruhn, H.; Mourier, A.; Wibom, R.; Nennesmo, I.; Jespers, A.; Govaert, P.; Ohtake, A.; Laer, L. Van; Loeys, B.L.; Freyer, C.; Palmieri, F.; Wredenberg, A.; Okazaki, Y.; Wedell, A.

2015-01-01

S-adenosylmethionine (SAM) is the predominant methyl group donor and has a large spectrum of target substrates. As such, it is essential for nearly all biological methylation reactions. SAM is synthesized by methionine adenosyltransferase from methionine and ATP in the cytoplasm and subsequently

Assay Methods for ACS Activity and ACS Phosphorylation by MAP Kinases In Vitro and In Vivo.

Science.gov (United States)

Han, Xiaomin; Li, Guojing; Zhang, Shuqun

2017-01-01

Ethylene, a gaseous phytohormone, has profound effects on plant growth, development, and adaptation to the environment. Ethylene-regulated processes begin with the induction of ethylene biosynthesis. There are two key steps in ethylene biosynthesis. The first is the biosynthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) from S-Adenosyl-Methionine (SAM), a common precursor in many metabolic pathways, which is catalyzed by ACC synthase (ACS). The second is the oxidative cleavage of ACC to form ethylene under the action of ACC oxidase (ACO). ACC biosynthesis is the committing and generally the rate-limiting step in ethylene biosynthesis. As a result, characterizing the cellular ACS activity and understanding its regulation are important. In this chapter, we detail the methods used to measure, (1) the enzymatic activity of both recombinant and native ACS proteins, and (2) the phosphorylation of ACS protein by mitogen-activated protein kinases (MAPKs) in vivo and in vitro.

Molecular junctions based on SAMs of cruciform oligo(phenylene ethynylene)s

DEFF Research Database (Denmark)

Wei, Zhongming; Li, Tao; Jennum, Karsten Stein

2012-01-01

Cruciform oligo(phenylene ethynylene)s (OPEs) with an extended tetrathiafulvalene (TTF) donor moiety (OPE5-TTF and OPE3-TTF) and their simple analogues (OPE5-S and OPE3) without conjugated substituents were used to form high quality self-assembled monolayers (SAMs) on ultra-flat gold substrates...

Effects of randomized supplementation of methionine or alanine on cysteine and glutathione production during the early phase of treatment of children with edematous malnutrition

Science.gov (United States)

We have shown that a low glutathione concentration and synthesis rate in erythrocytes are associated with a shortage of protein-derived cysteine in children with edematous severe acute malnutrition (SAM). We tested the hypothesis that methionine supplementation may increase protein-derived cysteine ...

Molecular cloning and functional expression of a stress-induced multifunctional O-methyltransferase with pinosylvin methyltransferase activity from Scots pine (Pinus sylvestris L.).

Science.gov (United States)

Chiron, H; Drouet, A; Claudot, A C; Eckerskorn, C; Trost, M; Heller, W; Ernst, D; Sandermann, H

2000-12-01

Formation of pinosylvin (PS) and pinosylvin 3-O-monomethyl ether (PSM), as well as the activities of stilbene synthase (STS) and S-adenosyl-1-methionine (SAM):pinosylvin O-methyltransferase (PMT), were induced strongly in needles of Scots pine seedlings upon ozone treatment, as well as in cell suspension cultures of Scots pine upon fungal elicitation. A SAM-dependent PMT protein was purified and partially characterised. A cDNA encoding PMT was isolated from an ozone-induced Scots pine cDNA library. Southern blot analysis of the genomic DNA suggested the presence of a gene family. The deduced protein sequence showed the typical highly conserved regions of O-methyltransferases (OMTs), and average identities of 20-56% to known OMTs. PMT expressed in Escherichia coli corresponded to that of purified PMT (40 kDa) from pine cell cultures. The recombinant enzyme catalysed the methylation of PS, caffeic acid, caffeoyl-CoA and quercetin. Several other substances, such as astringenin, resveratrol, 5-OH-ferulic acid, catechol and luteolin, were also methylated. Recombinant PMT thus had a relatively broad substrate specificity. Treatment of 7-year old Scots pine trees with ozone markedly increased the PMT mRNA level. Our results show that PMT represents a new SAM-dependent OMT for the methylation of stress-induced pinosylvin in Scots pine needles.

The role of surface electrostatics on the stability, function and regulation of human cystathionine β-synthase, a complex multidomain and oligomeric protein.

Science.gov (United States)

Pey, Angel L; Majtan, Tomas; Kraus, Jan P

2014-09-01

Human cystathionine β-synthase (hCBS) is a key enzyme of sulfur amino acid metabolism, controlling the commitment of homocysteine to the transsulfuration pathway and antioxidant defense. Mutations in hCBS cause inherited homocystinuria (HCU), a rare inborn error of metabolism characterized by accumulation of toxic homocysteine in blood and urine. hCBS is a complex multidomain and oligomeric protein whose activity and stability are independently regulated by the binding of S-adenosyl-methionine (SAM) to two different types of sites at its C-terminal regulatory domain. Here we study the role of surface electrostatics on the complex regulation and stability of hCBS using biophysical and biochemical procedures. We show that the kinetic stability of the catalytic and regulatory domains is significantly affected by the modulation of surface electrostatics through noticeable structural and energetic changes along their denaturation pathways. We also show that surface electrostatics strongly affect SAM binding properties to those sites responsible for either enzyme activation or kinetic stabilization. Our results provide new insight into the regulation of hCBS activity and stability in vivo with implications for understanding HCU as a conformational disease. We also lend experimental support to the role of electrostatic interactions in the recently proposed binding modes of SAM leading to hCBS activation and kinetic stabilization. Copyright © 2014 Elsevier B.V. All rights reserved.

SAM Theory Manual

Energy Technology Data Exchange (ETDEWEB)

Hu, Rui [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-03-01

The System Analysis Module (SAM) is an advanced and modern system analysis tool being developed at Argonne National Laboratory under the U.S. DOE Office of Nuclear Energy’s Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. SAM development aims for advances in physical modeling, numerical methods, and software engineering to enhance its user experience and usability for reactor transient analyses. To facilitate the code development, SAM utilizes an object-oriented application framework (MOOSE), and its underlying meshing and finite-element library (libMesh) and linear and non-linear solvers (PETSc), to leverage modern advanced software environments and numerical methods. SAM focuses on modeling advanced reactor concepts such as SFRs (sodium fast reactors), LFRs (lead-cooled fast reactors), and FHRs (fluoride-salt-cooled high temperature reactors) or MSRs (molten salt reactors). These advanced concepts are distinguished from light-water reactors in their use of single-phase, low-pressure, high-temperature, and low Prandtl number (sodium and lead) coolants. As a new code development, the initial effort has been focused on modeling and simulation capabilities of heat transfer and single-phase fluid dynamics responses in Sodium-cooled Fast Reactor (SFR) systems. The system-level simulation capabilities of fluid flow and heat transfer in general engineering systems and typical SFRs have been verified and validated. This document provides the theoretical and technical basis of the code to help users understand the underlying physical models (such as governing equations, closure models, and component models), system modeling approaches, numerical discretization and solution methods, and the overall capabilities in SAM. As the code is still under ongoing development, this SAM Theory Manual will be updated periodically to keep it consistent with the state of the development.

CAM and Hepatitis C: A Focus on Herbal Supplements

Science.gov (United States)

... sophora root), chlorella (a type of algae), black cumin (Nigella sativa) , S-adenosyl-L-methionine (SAMe), and thymus ... 184. Prasad AS. Zinc: role in immunity, oxidative stress and chronic inflammation . Current Opinion in Clinical Nutrition ...

MAT1A variants are associated with hypertension, stroke, and DNA damage and are modulated by vlasma vitamin B6 and folate concentration

Science.gov (United States)

Elevated plasma homocysteine is a cardiovascular disease (CVD) risk factor. However, the mechanism underlying this relationship is not understood. S-adenosylmethionine synthetase isoform type-1 (MAT1A) is a key enzyme in the metabolism of homocysteine, converting dietary methionine into S-adenosyl m...

Functional characterization of KanP, a methyltransferase from the kanamycin biosynthetic gene cluster of Streptomyces kanamyceticus.

Science.gov (United States)

Nepal, Keshav Kumar; Yoo, Jin Cheol; Sohng, Jae Kyung

2010-09-20

KanP, a putative methyltransferase, is located in the kanamycin biosynthetic gene cluster of Streptomyces kanamyceticus ATCC12853. Amino acid sequence analysis of KanP revealed the presence of S-adenosyl-L-methionine binding motifs, which are present in other O-methyltransferases. The kanP gene was expressed in Escherichia coli BL21 (DE3) to generate the E. coli KANP recombinant strain. The conversion of external quercetin to methylated quercetin in the culture extract of E. coli KANP proved the function of kanP as S-adenosyl-L-methionine-dependent methyltransferase. This is the first report concerning the identification of an O-methyltransferase gene from the kanamycin gene cluster. The resistant activity assay and RT-PCR analysis demonstrated the leeway for obtaining methylated kanamycin derivatives from the wild-type strain of kanamycin producer. 2009 Elsevier GmbH. All rights reserved.

Crystallization and preliminary crystallographic analysis of tRNA (m{sup 7}G46) methyltransferase from Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Liu, Qi; Gao, Yang; Yang, Weili; Zhou, Huihao; Gao, Yongxiang; Zhang, Xiao; Teng, Maikun, E-mail: mkteng@ustc.edu.cn; Niu, Liwen, E-mail: mkteng@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027 (China); Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027 (China)

2008-08-01

tRNA (m{sup 7}G46) methyltransferase from E. coli was overexpressed, purified and crystallized. Diffraction data were collected to 2.04 Å resolution. Transfer RNA (tRNA) (m{sup 7}G46) methyltransferase (TrmB) belongs to the Rossmann-fold methyltransferase (RFM) family and uses S-adenosyl-l-methionine (SAM) as the methyl-group donor to catalyze the formation of N{sup 7}-methylguanosine (m{sup 7}G) at position 46 in the variable loop of tRNAs. After attempts to crystallize full-length Escherichia coli TrmB (EcTrmB) failed, a truncated protein lacking the first 32 residues of the N-terminus but with an additional His{sub 6} tag at the C-terminus was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 3350 (PEG 3350) as precipitant at 283 K. An X-ray diffraction data set was collected using a single flash-cooled crystal that belonged to space group P2{sub 1}.

Crystallization and preliminary crystallographic analysis of tRNA (m7G46) methyltransferase from Escherichia coli

International Nuclear Information System (INIS)

Liu, Qi; Gao, Yang; Yang, Weili; Zhou, Huihao; Gao, Yongxiang; Zhang, Xiao; Teng, Maikun; Niu, Liwen

2008-01-01

tRNA (m 7 G46) methyltransferase from E. coli was overexpressed, purified and crystallized. Diffraction data were collected to 2.04 Å resolution. Transfer RNA (tRNA) (m 7 G46) methyltransferase (TrmB) belongs to the Rossmann-fold methyltransferase (RFM) family and uses S-adenosyl-l-methionine (SAM) as the methyl-group donor to catalyze the formation of N 7 -methylguanosine (m 7 G) at position 46 in the variable loop of tRNAs. After attempts to crystallize full-length Escherichia coli TrmB (EcTrmB) failed, a truncated protein lacking the first 32 residues of the N-terminus but with an additional His 6 tag at the C-terminus was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 3350 (PEG 3350) as precipitant at 283 K. An X-ray diffraction data set was collected using a single flash-cooled crystal that belonged to space group P2 1

The Emerging Role of Epigenetics on Dietary Treatment for Epilepsy

KAUST Repository

Landgrave Gomez, Jorge

2017-02-15

Purpose of ReviewSeizures are able to induce a wide range of complex alterations that may be due to abnormalities in gene expression patterns. In recent years, there has been resurgence regarding the use of dietary therapies for seizure treatment. Unfortunately, the precise mechanisms by which these therapies exert its effects remain unknown.Recent FindingsRecent evidence suggest that dietary treatment, throughout a metabolic shift, could impact the concentration of some metabolites, such as beta-hydroxybutyrate (B-HB) or S-adenosyl methionine (SAM), which are able to modulate the activity of enzymes involved in regulatory processes that control gene expression. Despite of this evidence, only a few studies have fully explored this emerging field.SummaryThe purpose of this article is to discuss how dietary treatment, throughout these molecules, could influence epigenetic modifications that may be able to restore aberrant patterns of gene expression produced by seizures, having an impact on this complex disease, such as seizures or even in epileptogenesis.

An Iterative O-Methyltransferase Catalyzes 1,11-Dimethylation of Aspergillus fumigatus Fumaric Acid Amides.

Science.gov (United States)

Kalb, Daniel; Heinekamp, Thorsten; Schieferdecker, Sebastian; Nett, Markus; Brakhage, Axel A; Hoffmeister, Dirk

2016-10-04

S-adenosyl-l-methionine (SAM)-dependent methyltransfer is a common biosynthetic strategy to modify natural products. We investigated the previously uncharacterized Aspergillus fumigatus methyltransferase FtpM, which is encoded next to the bimodular fumaric acid amide synthetase FtpA. Structure elucidation of two new A. fumigatus natural products, the 1,11-dimethyl esters of fumaryl-l-tyrosine and fumaryl-l-phenylalanine, together with ftpM gene disruption suggested that FtpM catalyzes iterative methylation. Final evidence that a single enzyme repeatedly acts on fumaric acid amides came from an in vitro biochemical investigation with recombinantly produced FtpM. Size-exclusion chromatography indicated that this methyltransferase is active as a dimer. As ftpA and ftpM homologues are found clustered in other fungi, we expect our work will help to identify and annotate natural product biosynthesis genes in various species. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Protein: MPA1 [TP Atlas

Lifescience Database Archive (English)

Full Text Available MPA1 TLR signaling molecules Rsad2 Vig1 Radical S-adenosyl methionine domain-containing pr...otein 2 Viperin, Virus inhibitory protein, endoplasmic reticulum-associated, interferon-inducible 10090 Mus musculus 58185 Q8CBB9 21435586 ...

System Advisor Model, SAM 2014.1.14: General Description

Energy Technology Data Exchange (ETDEWEB)

Blair, Nate [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dobos, Aron P. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Freeman, Janine [National Renewable Energy Lab. (NREL), Golden, CO (United States); Neises, Ty [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wagner, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ferguson, Tom [Global Resources, Northbrook, IL (United States); Gilman, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Janzou, Steven [Janzou Consulting, Idaho Springs, CO (United States)

2014-02-01

This document describes the capabilities of the U.S. Department of Energy and National Renewable Energy Laboratory's System Advisor Model (SAM), Version 2013.9.20, released on September 9, 2013. SAM is a computer model that calculates performance and financial metrics of renewable energy systems. Project developers, policy makers, equipment manufacturers, and researchers use graphs and tables of SAM results in the process of evaluating financial, technology, and incentive options for renewable energy projects. SAM simulates the performance of photovoltaic, concentrating solar power, solar water heating, wind, geothermal, biomass, and conventional power systems. The financial model can represent financial structures for projects that either buy and sell electricity at retail rates (residential and commercial) or sell electricity at a price determined in a power purchase agreement (utility). SAM's advanced simulation options facilitate parametric and sensitivity analyses, and statistical analysis capabilities are available for Monte Carlo simulation and weather variability (P50/P90) studies. SAM can also read input variables from Microsoft Excel worksheets. For software developers, the SAM software development kit (SDK) makes it possible to use SAM simulation modules in their applications written in C/C++, C#, Java, Python, and MATLAB. NREL provides both SAM and the SDK as free downloads at http://sam.nrel.gov. Technical support and more information about the software are available on the website.

SAM International Case Studies: DPV Analysis in Mexico

Energy Technology Data Exchange (ETDEWEB)

McCall, James D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-03-28

Presentation demonstrates the use of the System Advisor Model (SAM) in international analyses, specifically Mexico. Two analyses are discussed with relation to SAM modelling efforts: 1) Customer impacts from changes to net metering and billing agreements and 2) Potential benefits of PV for Mexican solar customers, the Mexican Treasury, and the environment. Along with the SAM analyses, integration of the International Utility Rate Database (I-URDB) with SAM and future international SAM work are discussed. Presentation was created for the International Solar Energy Society's (ISES) webinar titled 'International use of the NREL System Advisor Model (SAM) with case studies'.

SAM Photovoltaic Model Technical Reference 2016 Update

Energy Technology Data Exchange (ETDEWEB)

Gilman, Paul [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DiOrio, Nicholas A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Freeman, Janine M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Janzou, Steven [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dobos, Aron [No longer NREL employee; Ryberg, David [No longer NREL employee

2018-03-19

This manual describes the photovoltaic performance model in the System Advisor Model (SAM) software, Version 2016.3.14 Revision 4 (SSC Version 160). It is an update to the 2015 edition of the manual, which describes the photovoltaic model in SAM 2015.1.30 (SSC 41). This new edition includes corrections of errors in the 2015 edition and descriptions of new features introduced in SAM 2016.3.14, including: 3D shade calculator Battery storage model DC power optimizer loss inputs Snow loss model Plane-of-array irradiance input from weather file option Support for sub-hourly simulations Self-shading works with all four subarrays, and uses same algorithm for fixed arrays and one-axis tracking Linear self-shading algorithm for thin-film modules Loss percentages replace derate factors. The photovoltaic performance model is one of the modules in the SAM Simulation Core (SSC), which is part of both SAM and the SAM SDK. SAM is a user-friedly desktop application for analysis of renewable energy projects. The SAM SDK (Software Development Kit) is for developers writing their own renewable energy analysis software based on SSC. This manual is written for users of both SAM and the SAM SDK wanting to learn more about the details of SAM's photovoltaic model.

Refined global methyl halide budgets with respect to rapeseed (Brassica napus) by life-cycle measurements

Science.gov (United States)

Jiao, Y.; Acdan, J.; Xu, R.; Deventer, M. J.; Rhew, R. C.

2017-12-01

A precise quantification of global methyl halide budgets is needed to evaluate the ozone depletion potential of these compounds and to predict future changes of stratospheric ozone. However, the global budgets of methyl halides are not balanced between currently identified and quantified sources and sinks. Our study re-evaluated the methyl bromide budget from global cultivated rapeseed (Brassica napus) through life-cycle flux measurements both in the greenhouse and in the field, yielding a methyl bromide emission rate that scales globally to 1.0 - 1.2 Gg yr-1. While this indicates a globally significant source, it is much smaller than the previously widely cited value of 5 - 6 Gg yr-1(Mead et al., 2008), even taking into account the near tripling of annual global yield of rapeseed since the previous evaluation was conducted. Our study also evaluated the methyl chloride and methyl iodide emission levels from rapeseed, yielding emission rates that scale to 5.4 Gg yr-1 for methyl chloride and 1.8 Gg yr-1 of methyl iodide. The concentrations of the methyl donor SAM (S-adenosyl methionine) and the resultant product SAH (S-Adenosyl-L-homocysteine) were also analyzed to explore their role in biogenic methyl halide formation. Halide gradient incubations showed that the magnitude of methyl halide emissions from rapeseed is highly correlated to soil halide levels, thus raising the concern that the heterogeneity of soil halide contents geographically should be considered when extrapolating to global budget.

A common transport system for methionine, L-methionine-DL-sulfoximine (MSX), and phosphinothricin (PPT) in the diazotrophic cyanobacterium Nostoc muscorum.

Science.gov (United States)

Singh, Arvind Kumar; Syiem, Mayashree B; Singh, Rajkumar S; Adhikari, Samrat; Rai, Amar Nath

2008-05-01

We present evidence, for the first time, of the occurrence of a transport system common for amino acid methionine, and methionine/glutamate analogues L-methionine-DL-sulfoximine (MSX) and phosphinothricin (PPT) in cyanobacterium Nostoc muscorum. Methionine, which is toxic to cyanobacterium, enhanced its nitrogenase activity at lower concentrations. The cyanobacterium showed a biphasic pattern of methionine uptake activity that was competitively inhibited by the amino acids alanine, isoleucine, leucine, phenylalanine, proline, valine, glutamine, and asparagine. The methionine/glutamate analogue-resistant N. muscorum strains (MSX-R and PPT-R strains) also showed methionine-resistant phenotype accompanied by a drastic decrease in 35S methionine uptake activity. Treatment of protein extracts from these mutant strains with MSX and PPT reduced biosynthetic glutamine synthetase (GS) activity only in vitro and not in vivo. This finding implicated that MSX- and PPT-R phenotypes may have arisen due to a defect in their MSX and PPT transport activity. The simultaneous decrease in methionine uptake activity and in vitro sensitivity toward MSX and PPT of GS protein in MSX- and PPT-R strains indicated that methionine, MSX, and PPT have a common transport system that is shared by other amino acids as well in N. muscorum. Such information can become useful for isolation of methionine-producing cyanobacterial strains.

Structural insight into maintenance methylation by mouse DNA methyltransferase 1 (Dnmt1)

Science.gov (United States)

Takeshita, Kohei; Suetake, Isao; Yamashita, Eiki; Suga, Michihiro; Narita, Hirotaka; Nakagawa, Atsushi; Tajima, Shoji

2011-01-01

Methylation of cytosine in DNA plays a crucial role in development through inheritable gene silencing. The DNA methyltransferase Dnmt1 is responsible for the propagation of methylation patterns to the next generation via its preferential methylation of hemimethylated CpG sites in the genome; however, how Dnmt1 maintains methylation patterns is not fully understood. Here we report the crystal structure of the large fragment (291–1620) of mouse Dnmt1 and its complexes with cofactor S-adenosyl-L-methionine and its product S-adenosyl-L-homocystein. Notably, in the absence of DNA, the N-terminal domain responsible for targeting Dnmt1 to replication foci is inserted into the DNA-binding pocket, indicating that this domain must be removed for methylation to occur. Upon binding of S-adenosyl-L-methionine, the catalytic cysteine residue undergoes a conformation transition to a catalytically competent position. For the recognition of hemimethylated DNA, Dnmt1 is expected to utilize a target recognition domain that overhangs the putative DNA-binding pocket. Taking into considerations the recent report of a shorter fragment structure of Dnmt1 that the CXXC motif positions itself in the catalytic pocket and prevents aberrant de novo methylation, we propose that maintenance methylation is a multistep process accompanied by structural changes. PMID:21518897

Metabolism of 5-methylthioribose to methionine

International Nuclear Information System (INIS)

Miyazaki, J.H.; Yang, S.F.

1987-01-01

During ethylene biosynthesis, the H 3 CS-group of S-adenosylmethionine is released as 5'-methylthioadenosine, which is recycled to methionine via 5-methylthioribose (MTR). In mungbean hypocotyls and cell-free extracts of avocado, [ 14 C]MTR was converted into labeled methionine via 2-keto-4-methylthiobutyric acid (KMB) and 2-hydroxy-4-methylthiobutyric acid (HMB), as intermediates. Incubation of [ribose-U- 14 C]MTR with avocado extract resulted in the production of [ 14 C]formate, indicating the conversion of MTR to KMB involves a loss of formate, presumably from C-1 of MTR. Tracer studies showed that KMB was converted readily in vivo and in vitro to methionine, while HMB was converted much more slowly. The conversion of KMB to methionine by dialyzed avocado extract requires an amino donor. Among several potential donors examined, L-glutamine was the most efficient. Anaerobiosis inhibited only partially the oxidation of MTR to formate, KMB/HMB, and methionine by avocado extract. The role of O 2 in the conversion of MTR to methionine is discussed

The Pseudomonas aeruginosa autoinducer dodecanoyl-homoserine lactone inhibits the putrescine synthesis in human cells

DEFF Research Database (Denmark)

Kristiansen, S.; Bjarnsholt, Thomas; Adeltoft, D.

2008-01-01

Pseudomonas aeruginosa uses acyl-homoserine lactones to coordinate gene transcription in a process called quorum sensing (QS). The QS molecules C-4-HSL and C-12-oxo-HSL are synthesized from the universal precursor S-adenosyl methionine, which is also a precursor of polyamines in human cells...

A Rapid and Efficient Assay for the Characterization of Substrates and Inhibitors of Nicotinamide N-Methyltransferase

NARCIS (Netherlands)

van Haren, Matthijs J; Sastre Torano, Javier; Sartini, Davide; Emanuelli, Monica; Parsons, Richard B; Martin, Nathaniel I

2016-01-01

Nicotinamide N-methyltransferase (NNMT) is one of the most abundant small molecule methyltransferases in the human body and is primarily responsible for the N-methylation of the nicotinamide (vitamin B3). Employing the cofactor S-adenosyl-l-methionine, NNMT transfers a methyl group to the pyridine

The Au-S bond and SAM-protein contact in long-range electron transfer of pure and biomimetic metalloproteins via functionalized alkanethiol linkers

DEFF Research Database (Denmark)

Chi, Qijin; Ford, Michael J.; Halder, Arnab

disentangled a wealth of data to identify the nature of the crucial Au-S contact, all suggesting prevalence of a Au(0)-thiyl radical unit. Molecular packing is further determined by the SAM molecular structure and involves binding either to Au-atoms mined out of the surface or directly to a flat surface. We...... functionalized alkanethiols have emerged as core linkers. We have studied molecular linking in the long-range ET (LRET) processes in detail using electrochemistry, in situ STM and AFM, and electronic structure computations. A focus is the electronic structure of the Au-S link and the SAM packing. We have...... is exceedingly sensitive to the structure of the thiol-based SAM molecules, testifying to the crucial importance of SAM packing and Au-S binding, and of the SAM link to the protein. Some of the subtleties are illustrated simpler by similar size (5-6 nm) nanoparticles (NPs). Biomimetic NPs must possess a certain...

Technical Manual for the SAM Physical Trough Model

Energy Technology Data Exchange (ETDEWEB)

Wagner, M. J.; Gilman, P.

2011-06-01

NREL, in conjunction with Sandia National Lab and the U.S Department of Energy, developed the System Advisor Model (SAM) analysis tool for renewable energy system performance and economic analysis. This paper documents the technical background and engineering formulation for one of SAM's two parabolic trough system models in SAM. The Physical Trough model calculates performance relationships based on physical first principles where possible, allowing the modeler to predict electricity production for a wider range of component geometries than is possible in the Empirical Trough model. This document describes the major parabolic trough plant subsystems in detail including the solar field, power block, thermal storage, piping, auxiliary heating, and control systems. This model makes use of both existing subsystem performance modeling approaches, and new approaches developed specifically for SAM.

Macro-and micro-autoradiographic study in comparison with the incorporation of 35S-methionine by various tissue protein in organism

International Nuclear Information System (INIS)

Zhu Shoupeng; Mei Shengping; Le Shangcheng

1990-12-01

The purpose of the study was to observe the incorporation level of 35 S-methionine by various tissue protein in organism. By the use of the macro-and micro-autoradiographic technique, the incorporation of 35 S-methionine by the tissues has been utilized as an index of various tissue protein synthesis. On this basis, the further experiments showed that tracer agent 35 S-methionine was dominantly incorporated in the immature cells of bone marrow and the tissue of liver, kidney and spleen. Its incorporation increased gradually with time. From the experimental results it can be concluded that a strong protein biosynthesis metabolism was produced in these tissues. While the tissues have important physiological function in organism, such as heart, lung and skeletal muscle, but the protein biosynthesis in those tissues was at a low level

Homology modeling of Homo sapiens lipoic acid synthase: Substrate docking and insights on its binding mode.

Science.gov (United States)

Krishnamoorthy, Ezhilarasi; Hassan, Sameer; Hanna, Luke Elizabeth; Padmalayam, Indira; Rajaram, Rama; Viswanathan, Vijay

2017-05-07

Lipoic acid synthase (LIAS) is an iron-sulfur cluster mitochondrial enzyme which catalyzes the final step in the de novo pathway for the biosynthesis of lipoic acid, a potent antioxidant. Recently there has been significant interest in its role in metabolic diseases and its deficiency in LIAS expression has been linked to conditions such as diabetes, atherosclerosis and neonatal-onset epilepsy, suggesting a strong inverse correlation between LIAS reduction and disease status. In this study we use a bioinformatics approach to predict its structure, which would be helpful to understanding its role. A homology model for LIAS protein was generated using X-ray crystallographic structure of Thermosynechococcus elongatus BP-1 (PDB ID: 4U0P). The predicted structure has 93% of the residues in the most favour region of Ramachandran plot. The active site of LIAS protein was mapped and docked with S-Adenosyl Methionine (SAM) using GOLD software. The LIAS-SAM complex was further refined using molecular dynamics simulation within the subsite 1 and subsite 3 of the active site. To the best of our knowledge, this is the first study to report a reliable homology model of LIAS protein. This study will facilitate a better understanding mode of action of the enzyme-substrate complex for future studies in designing drugs that can target LIAS protein. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sam37 is crucial for formation of the mitochondrial TOM-SAM supercomplex, thereby promoting β-barrel biogenesis.

Science.gov (United States)

Wenz, Lena-Sophie; Ellenrieder, Lars; Qiu, Jian; Bohnert, Maria; Zufall, Nicole; van der Laan, Martin; Pfanner, Nikolaus; Wiedemann, Nils; Becker, Thomas

2015-09-28

Biogenesis of mitochondrial β-barrel proteins requires two preprotein translocases, the general translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). TOM and SAM form a supercomplex that promotes transfer of β-barrel precursors. The SAM core complex contains the channel protein Sam50, which cooperates with Sam35 in precursor recognition, and the peripheral membrane protein Sam37. The molecular function of Sam37 has been unknown. We report that Sam37 is crucial for formation of the TOM-SAM supercomplex. Sam37 interacts with the receptor domain of Tom22 on the cytosolic side of the mitochondrial outer membrane and links TOM and SAM complexes. Sam37 thus promotes efficient transfer of β-barrel precursors to the SAM complex. We conclude that Sam37 functions as a coupling factor of the translocase supercomplex of the mitochondrial outer membrane. © 2015 Wenz et al.

The tylosin resistance gene tlrB of Streptomyces fradiae encodes a methyltransferase that targets G748 in 23S rRNA

DEFF Research Database (Denmark)

Liu, M; Kirpekar, F; Van Wezel, G P

2000-01-01

tlrB is one of four resistance genes encoded in the operon for biosynthesis of the macrolide tylosin in antibiotic-producing strains of Streptomyces fradiae. Introduction of tlrB into Streptomyces lividans similarly confers tylosin resistance. Biochemical analysis of the rRNA from the two...... is dependent on the presence of the methyl group donor, S-adenosyl methionine. Analysis of the 74-mer RNA substrate by biochemical and mass spectrometric methods shows that TlrB adds a single methyl group to the base of G748. Homologues of TlrB in other bacteria have been revealed through database searches...

One-carbon metabolism, cognitive impairment and CSF measures of Alzheimer pathology: homocysteine and beyond.

Science.gov (United States)

Dayon, Loïc; Guiraud, Seu Ping; Corthésy, John; Da Silva, Laeticia; Migliavacca, Eugenia; Tautvydaitė, Domilė; Oikonomidi, Aikaterini; Moullet, Barbara; Henry, Hugues; Métairon, Sylviane; Marquis, Julien; Descombes, Patrick; Collino, Sebastiano; Martin, François-Pierre J; Montoliu, Ivan; Kussmann, Martin; Wojcik, Jérôme; Bowman, Gene L; Popp, Julius

2017-06-17

Hyperhomocysteinemia is a risk factor for cognitive decline and dementia, including Alzheimer disease (AD). Homocysteine (Hcy) is a sulfur-containing amino acid and metabolite of the methionine pathway. The interrelated methionine, purine, and thymidylate cycles constitute the one-carbon metabolism that plays a critical role in the synthesis of DNA, neurotransmitters, phospholipids, and myelin. In this study, we tested the hypothesis that one-carbon metabolites beyond Hcy are relevant to cognitive function and cerebrospinal fluid (CSF) measures of AD pathology in older adults. Cross-sectional analysis was performed on matched CSF and plasma collected from 120 older community-dwelling adults with (n = 72) or without (n = 48) cognitive impairment. Liquid chromatography-mass spectrometry was performed to quantify one-carbon metabolites and their cofactors. Least absolute shrinkage and selection operator (LASSO) regression was initially applied to clinical and biomarker measures that generate the highest diagnostic accuracy of a priori-defined cognitive impairment (Clinical Dementia Rating-based) and AD pathology (i.e., CSF tau phosphorylated at threonine 181 [p-tau181]/β-Amyloid 1-42 peptide chain [Aβ 1-42 ] >0.0779) to establish a reference benchmark. Two other LASSO-determined models were generated that included the one-carbon metabolites in CSF and then plasma. Correlations of CSF and plasma one-carbon metabolites with CSF amyloid and tau were explored. LASSO-determined models were stratified by apolipoprotein E (APOE) ε4 carrier status. The diagnostic accuracy of cognitive impairment for the reference model was 80.8% and included age, years of education, Aβ 1-42 , tau, and p-tau181. A model including CSF cystathionine, methionine, S-adenosyl-L-homocysteine (SAH), S-adenosylmethionine (SAM), serine, cysteine, and 5-methyltetrahydrofolate (5-MTHF) improved the diagnostic accuracy to 87.4%. A second model derived from plasma included cystathionine

Stereospecific enzymatic transformation of alpha-ketoglutarate to (2S,3R)-3-methyl glutamate during acidic lipopeptide biosynthesis.

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Mahlert, Christoph; Kopp, Florian; Thirlway, Jenny; Micklefield, Jason; Marahiel, Mohamed A

2007-10-03

The acidic lipopeptides, including the calcium-dependent antibiotics (CDA), daptomycin, and A54145, are important macrocyclic peptide natural products produced by Streptomyces species. All three compounds contain a 3-methyl glutamate (3-MeGlu) as the penultimate C-terminal residue, which is important for bioactivity. Here, biochemical in vitro reconstitution of the 3-MeGlu biosynthetic pathway is presented, using exclusively enzymes from the CDA producer Streptomyces coelicolor. It is shown that the predicted 3-MeGlu methyltransferase GlmT and its homologues DptI from the daptomycin producer Streptomyces roseosporus and LptI from the A54145 producer Streptomyces fradiae do not methylate free glutamic acid, PCP-bound glutamate, or Glu-containing CDA in vitro. Instead, GlmT, DptI, and LptI are S-adenosyl methionine (SAM)-dependent alpha-ketoglutarate methyltransferases that catalyze the stereospecific methylation of alpha-ketoglutarate (alphaKG) leading to (3R)-3-methyl-2-oxoglutarate. Subsequent enzyme screening identified the branched chain amino acid transaminase IlvE (SCO5523) as an efficient catalyst for the transformation of (3R)-3-methyl-2-oxoglutarate into (2S,3R)-3-MeGlu. Comparison of reversed-phase HPLC retention time of dabsylated 3-MeGlu generated by the coupled enzymatic reaction with dabsylated synthetic standards confirmed complete stereocontrol during enzymatic catalysis. This stereospecific two-step conversion of alphaKG to (2S,3R)-3-MeGlu completes our understanding of the biosynthesis and incorporation of beta-methylated amino acids into the nonribosomal lipopeptides. Finally, understanding this pathway may provide new possibilities for the production of modified peptides in engineered microbes.

Molecular cloning and characterization of juvenile hormone acid methyltransferase in the honey bee, Apis mellifera, and its differential expression during caste differentiation.

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Wenfeng Li

Full Text Available Juvenile hormone acid methyltransferase (JHAMT is an enzyme involved in one of the final steps of juvenile hormone biosynthesis in insects. It transfers a methyl group from S-adenosyl-L-methionine (SAM to the carboxyl group of either farnesoic acid (FA or JH acid (JHA. Several genes coding for JHAMT have been cloned and characterized from insects from different orders, and they have been shown to play critical roles in metamorphosis and reproduction. However, the significance of JHAMT in Hymenopteran insects is unknown. We used RACE amplification method to clone JHAMT cDNA from the honey bee, Apis mellifera (AmJHAMT. The full length cDNA of AmJHAMT that we cloned is 1253bp long and encodes a 278-aa protein that shares 32-36% identity with known JHAMTs. A SAM-binding motif, conserved in the SAM-dependent methyltransferase (SAM-MT superfamily, is present in AmJHAMT. Its secondary structure also contains a typical SAM-MT fold. Most of the active sites bound with SAM and substrates (JHA or FA are conserved in AmJHAMT as in other JHAMT orthologs. Phylogenetic analysis clustered AmJHAMT with the other orthologs from Hymenoptera to form a major clade in the phylogenetic tree. Purified recombinant AmJHAMT protein expressed in E. coli was used to produce polyclonal antibodies and to verify the identity of AmJHAMT by immunoblotting and mass spectrometry. Quantitative RT-PCR and immunoblotting analyses revealed that queen larvae contained significantly higher levels of AmJHAMT mRNA and protein than worker larvae during the periods of caste development. The temporal profiles of both AmJHAMT mRNA and protein in queens and workers showed a similar pattern as the JH biosynthesis. These results suggest that the gene that we cloned codes for a functional JHAMT that catalyzes the final reactions of JH biosynthesis in honey bees. In addition, AmJHAMT may play an important role in honey bee caste differentiation.

Folic Acid Reduces Tau Phosphorylation by Regulating PP2A Methylation in Streptozotocin-Induced Diabetic Mice

Science.gov (United States)

Zheng, Miaoyan; Zou, Chen; Li, Mengyue; Huang, Guowei; Gao, Yuxia; Liu, Huan

2017-01-01

High incidence rate of Alzheimer’s disease (AD) is observed in patients with type 2 diabetes. Aggregated β-amyloid (Aβ) and hyperphosphorylated tau are the hallmarks of AD. Hyperphosphorylated tau has been detected in diabetic animals as well as in diabetic patients. Folates mediate the transfer of one carbon unit, required in various biochemical reactions. The effect of folate on tau phosphorylation in diabetic models still remains unknown. In this study, we investigated the effect and mechanism of folic acid on hyperphosphorylation of tau in streptozotocin (STZ)-induced diabetic mice. Diabetic mice induced by STZ, at the age of 10 weeks, were administered with three levels of folic acid: folic acid-deficient diet, diet with normal folic acid content, and 120 μg/kg folic acid diet for 8 weeks. Levels of serum folate and blood glucose were monitored. Tau phosphorylation, protein phosphatase 2A (PP2A) methylation, and Glycogen synthase kinase 3β (GSK-3β) phosphorylation were detected using Western blot. The S-adenosyl methionine:S-adenosyl homocysteine ratio (SAM:SAH) in brain tissues was also determined. DNA methyltransferase (DNMT) mRNA expression levels were detected using real-time PCR. Folic acid reduced tau hyperphosphorylation at Ser396 in the brain of diabetes mellitus (DM) mice. In addition, PP2A methylation and DNMT1 mRNA expression were significantly increased in DM mice post folic acid treatment. GSK-3β phosphorylation was not regulated by folic acid administration. Folic acid can reduce tau phosphorylation by regulating PP2A methylation in diabetic mice. These results support that folic acid can serve as a multitarget neuronal therapeutic agent for treating diabetes-associated cognitive dysfunction. PMID:28422052

The chlamydial functional homolog of KsgA confers kasugamycin sensitivity to Chlamydia trachomatis and impacts bacterial fitness

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Maurelli Anthony T

2009-12-01

Full Text Available Abstract Background rRNA adenine dimethyltransferases, represented by the Escherichia coli KsgA protein, are highly conserved phylogenetically and are generally not essential for growth. They are responsible for the post-transcriptional transfer of two methyl groups to two universally conserved adenosines located near the 3'end of the small subunit rRNA and participate in ribosome maturation. All sequenced genomes of Chlamydia reveal a ksgA homolog in each species, including C. trachomatis. Yet absence of a S-adenosyl-methionine synthetase in Chlamydia, the conserved enzyme involved in the synthesis of the methyl donor S-adenosyl-L-methionine, raises a doubt concerning the activity of the KsgA homolog in these organisms. Results Lack of the dimethylated adenosines following ksgA inactivation confers resistance to kasugamycin (KSM in E. coli. Expression of the C. trachomatis L2 KsgA ortholog restored KSM sensitivity to the E. coli ksgA mutant, suggesting that the chlamydial KsgA homolog has specific rRNA dimethylase activity. C. trachomatis growth was sensitive to KSM and we were able to isolate a KSM resistant mutant of C. trachomatis containing a frameshift mutation in ksgA, which led to the formation of a shorter protein with no activity. Growth of the C. trachomatis ksgA mutant was negatively affected in cell culture highlighting the importance of the methylase in the development of these obligate intracellular and as yet genetically intractable pathogens. Conclusion The presence of a functional rRNA dimethylase enzyme belonging to the KsgA family in Chlamydia presents an excellent chemotherapeutic target with real potential. It also confirms the existence of S-adenosyl-methionine - dependent methylation reactions in Chlamydia raising the question of how these organisms acquire this cofactor.

Measurement of the delta34S value in methionine by double spike multi-collector thermal ionization mass spectrometry using Carius tube digestion.

Science.gov (United States)

Mann, Jacqueline L; Kelly, W Robert

2010-09-15

Methionine is an essential amino acid and is the primary source of sulfur for humans. Using the double spike ((33)S-(36)S) multi-collector thermal ionization mass spectrometry (MC-TIMS) technique, three sample bottles of a methionine material obtained from the Institute for Reference Materials and Measurements have been measured for delta(34)S and sulfur concentration. The mean delta(34)S value, relative to Vienna Canyon Diablo Troilite (VCDT), determined was 10.34 +/- 0.11 per thousand (n = 9) with the uncertainty reported as expanded uncertainties (U). These delta(34)S measurements include a correction for blank which has been previously ignored in studies of sulfur isotopic composition. The sulfur concentrations for the three bottles range from 56 to 88 microg/g. The isotope composition and concentration results demonstrate the high accuracy and precision of the DS-MC-TIMS technique for measuring sulfur in methionine.

In Salmonella enterica, the Gcn5-Related Acetyltransferase MddA (Formerly YncA) Acetylates Methionine Sulfoximine and Methionine Sulfone, Blocking Their Toxic Effects

Science.gov (United States)

Hentchel, Kristy L.

2014-01-01

Protein and small-molecule acylation reactions are widespread in nature. Many of the enzymes catalyzing acylation reactions belong to the Gcn5-related N-acetyltransferase (GNAT; PF00583) family, named after the yeast Gcn5 protein. The genome of Salmonella enterica serovar Typhimurium LT2 encodes 26 GNATs, 11 of which have no known physiological role. Here, we provide in vivo and in vitro evidence for the role of the MddA (methionine derivative detoxifier; formerly YncA) GNAT in the detoxification of oxidized forms of methionine, including methionine sulfoximine (MSX) and methionine sulfone (MSO). MSX and MSO inhibited the growth of an S. enterica ΔmddA strain unless glutamine or methionine was present in the medium. We used an in vitro spectrophotometric assay and mass spectrometry to show that MddA acetylated MSX and MSO. An mddA+ strain displayed biphasic growth kinetics in the presence of MSX and glutamine. Deletion of two amino acid transporters (GlnHPQ and MetNIQ) in a ΔmddA strain restored growth in the presence of MSX. Notably, MSO was transported by GlnHPQ but not by MetNIQ. In summary, MddA is the mechanism used by S. enterica to respond to oxidized forms of methionine, which MddA detoxifies by acetyl coenzyme A-dependent acetylation. PMID:25368301

Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger.

Science.gov (United States)

Manzanares-Miralles, Lara; Sarikaya-Bayram, Özlem; Smith, Elizabeth B; Dolan, Stephen K; Bayram, Özgür; Jones, Gary W; Doyle, Sean

2016-01-10

Gliotoxin (GT) is a redox-active metabolite, produced by Aspergillus fumigatus, which inhibits the growth of other fungi. Here we demonstrate how Aspergillus niger responds to GT exposure. Quantitative proteomics revealed that GT dysregulated the abundance of 378 proteins including those involved in methionine metabolism and induced de novo abundance of two S-adenosylmethionine (SAM)-dependent methyltransferases. Increased abundance of enzymes S-adenosylhomocysteinase (p=0.0018) required for homocysteine generation from S-adenosylhomocysteine (SAH), and spermidine synthase (p=0.0068), involved in the recycling of Met, was observed. Analysis of Met-related metabolites revealed significant increases in the levels of Met and adenosine, in correlation with proteomic data. Methyltransferase MT-II is responsible for bisthiobis(methylthio)gliotoxin (BmGT) formation, deletion of MT-II abolished BmGT formation and led to increased GT sensitivity in A. niger. Proteomic analysis also revealed that GT exposure also significantly (pniger. Thus, it provides new opportunities to exploit the response of GT-naïve fungi to GT. Copyright © 2015 Elsevier B.V. All rights reserved.

S-Adenosyl-L-Homocysteine Hydrolase Inhibition by a Synthetic Nicotinamide Cofactor Biomimetic

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Lyn L. Kailing

2018-03-01

Full Text Available S-adenosyl-L-homocysteine (SAH hydrolases (SAHases are involved in the regulation of methylation reactions in many organisms and are thus crucial for numerous cellular functions. Consequently, their dysregulation is associated with severe health problems. The SAHase-catalyzed reaction is reversible and both directions depend on the redox activity of nicotinamide adenine dinucleotide (NAD+ as a cofactor. Therefore, nicotinamide cofactor biomimetics (NCB are a promising tool to modulate SAHase activity. In the present in vitro study, we investigated 10 synthetic truncated NAD+ analogs against a SAHase from the root-nodulating bacterium Bradyrhizobium elkanii. Among this set of analogs, one was identified to inhibit the SAHase in both directions. Isothermal titration calorimetry (ITC and crystallography experiments suggest that the inhibitory effect is not mediated by a direct interaction with the protein. Neither the apo-enzyme (i.e., deprived of the natural cofactor, nor the holo-enzyme (i.e., in the NAD+-bound state were found to bind the inhibitor. Yet, enzyme kinetics point to a non-competitive inhibition mechanism, where the inhibitor acts on both, the enzyme and enzyme-SAH complex. Based on our experimental results, we hypothesize that the NCB inhibits the enzyme via oxidation of the enzyme-bound NADH, which may be accessible through an open molecular gate, leaving the enzyme stalled in a configuration with oxidized cofactor, where the reaction intermediate can be neither converted nor released. Since the reaction mechanism of SAHase is quite uncommon, this kind of inhibition could be a viable pharmacological route, with a low risk of off-target effects. The NCB presented in this work could be used as a template for the development of more potent SAHase inhibitors.

Biotechnological production of high specific activity L-35S-cysteine and L-35S-methionine by using a diploid yeast Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Gajendiran, N.; Jayachandran, N.; Unny, V.K.P.; Thyagarajan, S.; Rao, B.S.

1994-01-01

High specific activity L- 3 5 S-cysteine and L- 35 S-methionine were synthesised by using a wild type diploid strain of baker's yeast-Saccharomyces cerevisiae. Yeast cells were grown in a sulphur depleted synthetic medium in which Na 2 3 5 SO 4 (50 mCi/ml) was supplemented as the sole sulphur source. The level of incorporation was 60% on an average. The protein hydrolysate of the cultured cells was subjected to paper and column chromatographic separations to get the individual L- 3 5 S-aminoacids. The radiochemical yields of cysteine and methionine were 6-7% and 18-20% respectively. The radiochemical purity of the products was >95%. The highest specific activity for the products obtained by employing this method was 1100 Ci/mmole from the starting material, Na 2 35 SO 4 , with a specific activity of 1350 Ci/mmole. (Author)

Samâ’ dalam Tradisi Tasawuf

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Said Aqil Siradj

2014-01-01

Full Text Available Samâ‘ in Tasawuf has been a very important element in the dissemination of this spiritual dimension of Islam. Yet, it has received very little both from the practitioners of Tasawuf and its intellectuals. This paper tries to expose this simply in a hope to make it heard in the academic and popular circle. Here, samâ‘ is not only understood as a form of music, as many would do, but also as an art of listening of which music is certainly part. The paper will explore the meaning and definition of this term, putting emphasis on its many-faceted function in the formation and development of one’s soul and spirituality. It is argued that soul is musical and artistic. Using art and music to talk to soul is therefore the proper way and means. The paper will also try to show that samâ‘ is also an indispensable part of spiritual method to reach and know God. Knowledge of God in other words, can be gained through this practice. Hence, samâ‘ is treated not only as a form of entertainment, but also a kind of practical epistemology.

A novel multifunctional O-methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine.

Science.gov (United States)

Li, L; Popko, J L; Zhang, X H; Osakabe, K; Tsai, C J; Joshi, C P; Chiang, V L

1997-05-13

S-adenosyl-L-methionine (SAM)-dependent O-methyltransferases (OMTs) catalyze the methylation of hydroxycinnamic acid derivatives for the synthesis of methylated plant polyphenolics, including lignin. The distinction in the extent of methylation of lignins in angiosperms and gymnosperms, mediated by substrate-specific OMTs, represents one of the fundamental differences in lignin biosynthesis between these two classes of plants. In angiosperms, two types of structurally and functionally distinct lignin pathway OMTs, caffeic acid 3-O-methyltransferases (CAOMTs) and caffeoyl CoA 3-O-methyltransferases (CCoAOMTs), have been reported and extensively studied. However, little is known about lignin pathway OMTs in gymnosperms. We report here the first cloning of a loblolly pine (Pinus taeda) xylem cDNA encoding a multifunctional enzyme, SAM:hydroxycinnamic Acids/hydroxycinnamoyl CoA Esters OMT (AEOMT). The deduced protein sequence of AEOMT is partially similar to, but clearly distinguishable from, that of CAOMTs and does not exhibit any significant similarity with CCoAOMT protein sequences. However, functionally, yeast-expressed AEOMT enzyme catalyzed the methylation of CAOMT substrates, caffeic and 5-hydroxyferulic acids, as well as CCoAOMT substrates, caffeoyl CoA and 5-hydroxyferuloyl CoA esters, with similar specific activities and was completely inactive with substrates associated with flavonoid synthesis. The lignin-related substrates were also efficiently methylated in crude extracts of loblolly pine secondary xylem. Our results support the notion that, in the context of amino acid sequence and biochemical function, AEOMT represents a novel SAM-dependent OMT, with both CAOMT and CCoAOMT activities and thus the potential to mediate a dual methylation pathway in lignin biosynthesis in loblolly pine xylem.

A novel multifunctional O-methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine

Science.gov (United States)

Li, Laigeng; Popko, Jacqueline L.; Zhang, Xing-Hai; Osakabe, Keishi; Tsai, Chung-Jui; Joshi, Chandrashekhar P.; Chiang, Vincent L.

1997-01-01

S-adenosyl-l-methionine (SAM)-dependent O-methyltransferases (OMTs) catalyze the methylation of hydroxycinnamic acid derivatives for the synthesis of methylated plant polyphenolics, including lignin. The distinction in the extent of methylation of lignins in angiosperms and gymnosperms, mediated by substrate-specific OMTs, represents one of the fundamental differences in lignin biosynthesis between these two classes of plants. In angiosperms, two types of structurally and functionally distinct lignin pathway OMTs, caffeic acid 3-O-methyltransferases (CAOMTs) and caffeoyl CoA 3-O-methyltransferases (CCoAOMTs), have been reported and extensively studied. However, little is known about lignin pathway OMTs in gymnosperms. We report here the first cloning of a loblolly pine (Pinus taeda) xylem cDNA encoding a multifunctional enzyme, SAM:hydroxycinnamic Acids/hydroxycinnamoyl CoA Esters OMT (AEOMT). The deduced protein sequence of AEOMT is partially similar to, but clearly distinguishable from, that of CAOMTs and does not exhibit any significant similarity with CCoAOMT protein sequences. However, functionally, yeast-expressed AEOMT enzyme catalyzed the methylation of CAOMT substrates, caffeic and 5-hydroxyferulic acids, as well as CCoAOMT substrates, caffeoyl CoA and 5-hydroxyferuloyl CoA esters, with similar specific activities and was completely inactive with substrates associated with flavonoid synthesis. The lignin-related substrates were also efficiently methylated in crude extracts of loblolly pine secondary xylem. Our results support the notion that, in the context of amino acid sequence and biochemical function, AEOMT represents a novel SAM-dependent OMT, with both CAOMT and CCoAOMT activities and thus the potential to mediate a dual methylation pathway in lignin biosynthesis in loblolly pine xylem. PMID:9144260

Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca

Science.gov (United States)

Bruns, Hilke; Riclea, Ramona

2011-01-01

Summary The volatiles released by Micromonospora aurantiaca were collected by means of a closed-loop stripping apparatus (CLSA) and analysed by GC–MS. The headspace extracts contained more than 90 compounds from different classes. Fatty acid methyl esters (FAMEs) comprised the major compound class including saturated unbranched, monomethyl and dimethyl branched FAMEs in diverse structural variants: Unbranched, α-branched, γ-branched, (ω−1)-branched, (ω−2)-branched, α- and (ω−1)-branched, γ- and (ω−1)-branched, γ- and (ω−2)-branched, and γ- and (ω−3)-branched FAMEs. FAMEs of the last three types have not been described from natural sources before. The structures for all FAMEs have been suggested based on their mass spectra and on a retention index increment system and verified by the synthesis of key reference compounds. In addition, the structures of two FAMEs, methyl 4,8-dimethyldodecanoate and the ethyl-branched compound methyl 8-ethyl-4-methyldodecanoate were deduced from their mass spectra. Feeding experiments with isotopically labelled [2H10]leucine, [2H10]isoleucine, [2H8]valine, [2H5]sodium propionate, and [methyl-2H3]methionine demonstrated that the responsible fatty acid synthase (FAS) can use different branched and unbranched starter units and is able to incorporate methylmalonyl-CoA elongation units for internal methyl branches in various chain positions, while the methyl ester function is derived from S-adenosyl methionine (SAM). PMID:22238549

The Sam-Sam interaction between Ship2 and the EphA2 receptor: design and analysis of peptide inhibitors.

Science.gov (United States)

Mercurio, Flavia Anna; Di Natale, Concetta; Pirone, Luciano; Iannitti, Roberta; Marasco, Daniela; Pedone, Emilia Maria; Palumbo, Rosanna; Leone, Marilisa

2017-12-12

The lipid phosphatase Ship2 represents a drug discovery target for the treatment of different diseases, including cancer. Its C-terminal sterile alpha motif domain (Ship2-Sam) associates with the Sam domain from the EphA2 receptor (EphA2-Sam). This interaction is expected to mainly induce pro-oncogenic effects in cells therefore, inhibition of the Ship2-Sam/EphA2-Sam complex may represent an innovative route to discover anti-cancer therapeutics. In the present work, we designed and analyzed several peptide sequences encompassing the interaction interface of EphA2-Sam for Ship2-Sam. Peptide conformational analyses and interaction assays with Ship2-Sam conducted through diverse techniques (CD, NMR, SPR and MST), identified a positively charged penta-amino acid native motif in EphA2-Sam, that once repeated three times in tandem, binds Ship2-Sam. NMR experiments show that the peptide targets the negatively charged binding site of Ship2-Sam for EphA2-Sam. Preliminary in vitro cell-based assays indicate that -at 50 µM concentration- it induces necrosis of PC-3 prostate cancer cells with more cytotoxic effect on cancer cells than on normal dermal fibroblasts. This work represents a pioneering study that opens further opportunities for the development of inhibitors of the Ship2-Sam/EphA2-Sam complex for therapeutic applications.

A review of methionine dependency and the role of methionine restriction in cancer growth control and life-span extension.

Science.gov (United States)

Cavuoto, Paul; Fenech, Michael F

2012-10-01

Methionine is an essential amino acid with many key roles in mammalian metabolism such as protein synthesis, methylation of DNA and polyamine synthesis. Restriction of methionine may be an important strategy in cancer growth control particularly in cancers that exhibit dependence on methionine for survival and proliferation. Methionine dependence in cancer may be due to one or a combination of deletions, polymorphisms or alterations in expression of genes in the methionine de novo and salvage pathways. Cancer cells with these defects are unable to regenerate methionine via these pathways. Defects in the metabolism of folate may also contribute to the methionine dependence phenotype in cancer. Selective killing of methionine dependent cancer cells in co-culture with normal cells has been demonstrated using culture media deficient in methionine. Several animal studies utilizing a methionine restricted diet have reported inhibition of cancer growth and extension of a healthy life-span. In humans, vegan diets, which can be low in methionine, may prove to be a useful nutritional strategy in cancer growth control. The development of methioninase which depletes circulating levels of methionine may be another useful strategy in limiting cancer growth. The application of nutritional methionine restriction and methioninase in combination with chemotherapeutic regimens is the current focus of clinical studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Superoxide Mediates Depressive Effects Induced by Hydrogen Sulfide in Rostral Ventrolateral Medulla of Spontaneously Hypertensive Rats

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Haiyun Yu

2015-01-01

Full Text Available Hydrogen sulfide (H2S plays a crucial role in the regulation of blood pressure and oxidative stress. In the present study, we tested the hypothesis that H2S exerts its cardiovascular effects by reducing oxidative stress via inhibition of NADPH oxidase activity in the rostral ventrolateral medulla (RVLM. We examined cell distributions of cystathionine-β-synthase (CBS and effects of H2S on reactive oxygen species (ROS and mean arterial blood pressure (MAP in spontaneously hypertensive rats (SHRs. We found that CBS was expressed in neurons of the RVLM, and the expression was lower in SHRs than in Wistar-Kyoto rats. Microinjection of NaHS (H2S donor, S-adenosyl-l-methionine (SAM, a CBS agonist, or Apocynin (NADPH oxidase inhibitor into the RVLM reduced the ROS level, NADPH oxidase activity, and MAP, whereas microinjection of hydroxylamine hydrochloride (HA, a CBS inhibitor increased MAP. Furthermore, intracerebroventricular infusion of NaHS inhibited phosphorylation of p47phox, a key step of NADPH oxidase activation. Since decreasing ROS level in the RVLM reduces MAP and heart rate and increasing H2S reduces ROS production, we conclude that H2S exerts an antihypertensive effect via suppressing ROS production. H2S, as an antioxidant, may be a potential target for cardiovascular diseases.

Surface adhesion and confinement variation of Staphylococcus aurius on SAM surfaces

Science.gov (United States)

Amroski, Alicia; Olsen, Morgan; Calabrese, Joseph; Senevirathne, Reshani; Senevirathne, Indrajith

2012-02-01

Controlled surface adhesion of non - pathogenic gram positive strain, Staphylococcus aureus is interesting as a model system due to possible development of respective biosensors for prevention and detection of the pathogenic strain methicillin resistant Staphylococcus aureus (MRSA) and further as a study for bio-machine interfacing. Self Assembled Monolayers (SAM) with engineered surfaces of linear thiols on Au(111) were used as the substrate. Sub cultured S. aureus were used for the analysis. The SAM layered surfaces were dipped in 2 -- 4 Log/ml S. aureus solution. Subsequent surface adhesion at different bacterial dilutions on surfaces will be discussed, and correlated with quantitative and qualitative adhesion properties of bacteria on the engineered SAM surfaces. The bacteria adhered SAM surfaces were investigated using intermittent contact, noncontact, lateral force and contact modes of Atomic Force Microscopy (AFM).

Recent Updates to the System Advisor Model (SAM)

Energy Technology Data Exchange (ETDEWEB)

DiOrio, Nicholas A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-02-14

The System Advisor Model (SAM) is a mature suite of techno-economic models for many renewable energy technologies that can be downloaded for free as a desktop application or software development kit. SAM is used for system-level modeling, including generating performance pro the release of the code as an open source project on GitHub. Other additions that will be covered include the ability to download data directly into SAM from the National Solar Radiation Database (NSRDB) and up- dates to a user-interface macro that assists with PV system sizing. A brief update on SAM's battery model and its integration with the detailed photovoltaic model will also be discussed. Finally, an outline of planned work for the next year will be presented, including the addition of a bifacial model, support for multiple MPPT inputs for detailed inverter modeling, and the addition of a model for inverter thermal behavior.

Effect of different levels of lysine in the diet of broilers on the metabolism of /sup 35/S-methionine

Energy Technology Data Exchange (ETDEWEB)

Stanchev, Kh; Venkov, T; Dzharova, M [Akademiya na Selskostopanskite Nauki, Sofia-Kostinbrod (Bulgaria). Inst. po Zhivotnovydstvo

1974-01-01

The lack of balance of the ration with respect to lysine leads to a decrease in the rate of incorporation of /sup 35/S-methionine in the liver, pancreas, kidney and femoral muscle. Most intensive protein synthesis in the liver of chickens is observed in the group receiving ration balanced with respect to lysine while in the case of a deficiency or excess of lysine the protein biosynthesis drops. The deficiency or excess of lysine leads to an increase in the excretion rate and decreases the assimilability of radioactive methionine in the chickens organisms. (INIS)

Effect of certain active components from traditional Chinese medicinal herbs on Aβ secretion rate with L-[35S]-Methionine

International Nuclear Information System (INIS)

Hu Yaer; Zhang Naizheng; Li Aimin; Xia Zongqin

2006-01-01

To observe the effect of certain active components from traditional Chinese medicinal herbs on Aβ secretion rates with L-[ 35 S]-Methionine, β-amyloid peptide (Aβ) in SK-N-SH cell lines stably transfected with APP695 was metabolically labeled with L-[ 35 S]-Methionine. the supernatant from culture medium was immunoprecipitated with monoclonal antibody against Aβ 22-35 , Western blot was carried out, and the gray density of Aβ band in the autoradiograph was measured by an image analysis system. The active components from certain traditional Chinese medicinal herbs (ZMS from Zhimu and AST and HT from Huangqi) were added to the culture medium at a final concentration of 10 -5 mol/L. An Aβ band in the autoradiograph was clearly viewed in the culture medium after 24 h incorporation of [ -35 S]-Methionine which represent the secretion rate of Aβ by the cells. One of the 3 tested components (AST) could significantly reduce the Aβ secretion rate while the other two showed no effect. The preliminary result showed that certain active component from traditional Chinese medicines could decrease the Aβ secretion rate but other active components could not. Combined use of the AST and ZMS was more effective than single AST. (authors)

Biofuel and chemical production by recombinant microorganisms via fermentation of proteinaceous biomass

Science.gov (United States)

Liao, James C.; Cho, Kwang Myung; Yan, Yajun; Huo, Yixin

2016-03-15

Provided herein are metabolically modified microorganisms characterized by having an increased keto-acid flux when compared with the wild-type organism and comprising at least one polynucleotide encoding an enzyme that when expressed results in the production of a greater quantity of a chemical product when compared with the wild-type organism. The recombinant microorganisms are useful for producing a large number of chemical compositions from various nitrogen containing biomass compositions and other carbon sources. More specifically, provided herein are methods of producing alcohols, acetaldehyde, acetate, isobutyraldehyde, isobutyric acid, n-butyraldehyde, n-butyric acid, 2-methyl-1-butyraldehyde, 2-methyl-1-butyric acid, 3-methyl-1-butyraldehyde, 3-methyl-1-butyric acid, ammonia, ammonium, amino acids, 2,3-butanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 2-methyl-1,4-butanediamine, isobutene, itaconate, acetoin, acetone, isobutene, 1,5-diaminopentane, L-lactic acid, D-lactic acid, shikimic acid, mevalonate, polyhydroxybutyrate (PHB), isoprenoids, fatty acids, homoalanine, 4-aminobutyric acid (GABA), succinic acid, malic acid, citric acid, adipic acid, p-hydroxy-cinnamic acid, tetrahydrofuran, 3-methyl-tetrahydrofuran, gamma-butyrolactone, pyrrolidinone, n-methylpyrrolidone, aspartic acid, lysine, cadeverine, 2-ketoadipic acid, and/or S-adenosyl-methionine (SAM) from a suitable nitrogen rich biomass.

Aminopropyltransferases involved in polyamine biosynthesis localize preferentially in the nucleus of plant cells.

Directory of Open Access Journals (Sweden)

Borja Belda-Palazón

Full Text Available Plant aminopropyltransferases consist of a group of enzymes that transfer aminopropyl groups derived from decarboxylated S-adenosyl-methionine (dcAdoMet or dcSAM to propylamine acceptors to produce polyamines, ubiquitous metabolites with positive charge at physiological pH. Spermidine synthase (SPDS uses putrescine as amino acceptor to form spermidine, whereas spermine synthase (SPMS and thermospermine synthase (TSPMS use spermidine as acceptor to synthesize the isomers spermine and thermospermine respectively. In previous work it was shown that both SPDS1 and SPDS2 can physically interact with SPMS although no data concerning the subcellular localization was reported. Here we study the subcellular localization of these enzymes and their protein dimer complexes with gateway-based Bimolecular Fluorescence Complementation (BiFC binary vectors. In addition, we have characterized the molecular weight of the enzyme complexes by gel filtration chromatography with in vitro assembled recombinant enzymes and with endogenous plant protein extracts. Our data suggest that aminopropyltransferases display a dual subcellular localization both in the cytosol and nuclear enriched fractions, and they assemble preferably as dimers. The BiFC transient expression data suggest that aminopropyltransferase heterodimer complexes take place preferentially inside the nucleus.

A simple method for enzymatic synthesis of unlabeled and radiolabeled Hydroxycinnamate-CoA

Energy Technology Data Exchange (ETDEWEB)

Rautergarten, Carsten; Baidoo, Edward; Keasling, Jay; Vibe Scheller, Henrik

2011-07-20

Hydroxycinnamate coenzyme A (CoA) thioesters are substrates for biosynthesis of lignin and hydroxycinna- mate esters of polysaccharides and other polymers. Hence, a supply of these substrates is essential for investigation of cell wall biosynthesis. In this study, three recombinant enzymes, caffeic acid 3-O-methyltransferase, 4-coumarate- CoA ligase 1, and 4-coumarate-CoA ligase 5, were cloned from wheat, tobacco, and Arabidopsis, respectively, and were used to synthesize {sup 14}C-feruloyl-CoA, caffeoyl-CoA, p-coumaroyl-CoA, feruloyl-CoA, and sinapoyl-CoA. The corresponding hydroxycinnamoyl-CoA thioesters were high-performance liquid chromatography purified, the only extraction/purification step necessary, with total yields between 88-95%. Radiolabeled {sup 14}C-feruloyl-CoA was generated from caffeic acid and S-adenosyl-{sup 14}C-methionine under the combined action of caffeic acid 3-O-methyltransferase and 4-coumarate-CoA ligase 1. About 70% of {sup 14}C-methyl groups from S-adenosyl methionine were incorporated into the final product. The methods presented are simple, fast, and efficient for the preparation of the hydroxycinnamate thioesters.

Amine terminated SAMs: Investigating why oxygen is present in these films

International Nuclear Information System (INIS)

Baio, J.E.; Weidner, T.; Brison, J.; Graham, D.J.; Gamble, Lara J.; Castner, David G.

2009-01-01

Self-assembled monolayers (SAMs) on gold prepared from amine-terminated alkanethiols have long been employed as model positively charged surfaces. Yet in previous studies significant amounts of unexpected oxygen containing species are always detected in amine terminated SAMs. Thus, the goal of this investigation was to determine the source of these oxygen species and minimize their presence in the SAM. The surface composition, structure, and order of amine-terminated SAMs on Au were characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), sum frequency generation (SFG) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. XPS determined compositions of amine-terminated SAMs in the current study exhibited oxygen concentrations of 2.4 ± 0.4 atomic %, a substantially lower amount of oxygen than reported in previously published studies. High-resolution XPS results from the S 2p , C 1s and N 1s regions did not detect any oxidized species. Angle-resolved XPS indicated that the small amount of oxygen detected was located at or near the amine head group. Small amounts of oxidized nitrogen, carbon and sulfur secondary ions, as well as ions attributed to water, were detected in the ToF-SIMS data due to the higher sensitivity of ToF-SIMS. The lack of N-O, S-O, and C-O stretches in the SFG spectra are consistent with the XPS and ToF-SIMS results and together show that oxidation of the amine-terminated thiols alone can only account for, at most, a small fraction of the oxygen detected by XPS. Both the SFG and angle-dependent NEXAFS indicated the presence of gauche defects in the amine SAMs. However, the SFG spectral features near 2865 cm -1 , assigned to the stretch of the methylene group next to the terminal amine unit, demonstrate the SAM is reasonably ordered. The SFG results also show another broad feature near 3200 cm -1 related to hydrogen-bonded water. From this multi-technique investigation it is

Biological activity of antitumoural MGBG: the structural variable.

Science.gov (United States)

Marques, M P M; Gil, F P S C; Calheiros, R; Battaglia, V; Brunati, A M; Agostinelli, E; Toninello, A

2008-05-01

The present study aims at determining the structure-activity relationships (SAR's) ruling the biological function of MGBG (methylglyoxal bis(guanylhydrazone)), a competitive inhibitor of S-adenosyl-L-methionine decarboxylase displaying anticancer activity, involved in the biosynthesis of the naturally occurring polyamines spermidine and spermine. In order to properly understand its biochemical activity, MGBG's structural preferences at physiological conditions were ascertained, by quantum mechanical (DFT) calculations.

Oxidation of protein tyrosine or methionine residues: From the amino acid to the peptide

Energy Technology Data Exchange (ETDEWEB)

Berges, J [Universite Pierre et Marie Curie, UMR 7616, Laboratoire de Chimie Theorique, 75005 Paris (France); Trouillas, P [EA 4021 Faculte de Pharmacie, 2 Rue du Dr. Marcland, 87025 Limoges Cedex (France); Houee-Levin, C, E-mail: jb@lct.jussieu.fr, E-mail: patrick.trouillas@unilim.fr, E-mail: chantal.houee@u-psud.fr [Universite Paris Sud, UMR 8000, Laboratoire de Chimie Physique, 91405 Orsay (France) (France)

2011-01-01

Methionine and tyrosine are competing targets of oxidizing free radicals in peptides or proteins. The first step is the addition of OH radicals either on the sulphur atom of methionine, followed by OH{sup -} elimination, or on the aromatic cycle of tyrosine. The next step can be stabilization of methionine radical cation by a two centre-three electron bond, or intramolecular electron transfer from tyrosine to the methionine radical cation. In this latter case a tyrosine radical is formed, which appears deprotonated. In a first step we have compared the stability of the OH radical adducts on Methionine or on Tyrosine. In agreement with experimental results, the thermodynamical data indicate that the OH adduct on Tyrosine and the radical cation are more stable than those on methionine. In a second step we have investigated the stabilization of the radical cations of Methionine by formation of intramolecular S:X two-center three-electron bond (X=S, N, O). Finally we have compared the spin densities on separated amino acids to that in a radical pentapeptide, methionine enkephalin. One observes a delocalisation of the orbital of the odd electron on the sulfur atom of Met and on the cycle of Tyr. The peptidic chain is also concerned.

Oxidation of protein tyrosine or methionine residues: From the amino acid to the peptide

International Nuclear Information System (INIS)

Berges, J; Trouillas, P; Houee-Levin, C

2011-01-01

Methionine and tyrosine are competing targets of oxidizing free radicals in peptides or proteins. The first step is the addition of OH radicals either on the sulphur atom of methionine, followed by OH - elimination, or on the aromatic cycle of tyrosine. The next step can be stabilization of methionine radical cation by a two centre-three electron bond, or intramolecular electron transfer from tyrosine to the methionine radical cation. In this latter case a tyrosine radical is formed, which appears deprotonated. In a first step we have compared the stability of the OH radical adducts on Methionine or on Tyrosine. In agreement with experimental results, the thermodynamical data indicate that the OH adduct on Tyrosine and the radical cation are more stable than those on methionine. In a second step we have investigated the stabilization of the radical cations of Methionine by formation of intramolecular S:X two-center three-electron bond (X=S, N, O). Finally we have compared the spin densities on separated amino acids to that in a radical pentapeptide, methionine enkephalin. One observes a delocalisation of the orbital of the odd electron on the sulfur atom of Met and on the cycle of Tyr. The peptidic chain is also concerned.

Antileishmanial activity of berenil and methylglyoxal bis (guanylhydrazone) and its correlation with S-adenosylmethionine decarboxylase and polyamines.

Science.gov (United States)

Mukhopadhyay, R; Madhubala, R

1995-01-01

Leishmania donovani S-adenosyl-L-methionine (AdoMet) decarboxylase was found to show a growth related pattern. Methylglyoxal bis (guanylhydrazone) (MGBG) and Berenil inhibited the growth of Leishmania donovani promastigotes (strain UR6) in a dose dependent manner. The concentrations of MGBG and Berenil required for 50% inhibition of rate of growth were 67 and 47 microM, respectively. The growth inhibition of MGBG was partially reversed by spermidine (100 microM) and spermine (100 microM). Berenil inhibition of promastigote growth was partially reversed by 100 microM spermidine whereas 100 microM spermine did not result in any reversal of growth. The reduction in parasitemia in vitro by these inhibitors was accompanied by inhibition of AdoMet decarboxylase activity and spermidine levels.

Conversion of a disulfide bond into a thioacetal group during echinomycin biosynthesis

Energy Technology Data Exchange (ETDEWEB)

Hotta, Kinya; Keegan, Ronan M.; Ranganathan, Soumya; Fang, Minyi; Bibby, Jaclyn; Winn, Martyn D.; Sato, Michio; Lian, Mingzhu; Watanabe, Kenji; Rigden, Daniel J.; Kim, Chu-Young (Liverpool); (Daresbury); (NU Singapore); (Shizuoka); (RAL)

2013-12-02

Echinomycin is a nonribosomal depsipeptide natural product with a range of interesting bioactivities that make it an important target for drug discovery and development. It contains a thioacetal bridge, a unique chemical motif derived from the disulfide bond of its precursor antibiotic triostin A by the action of an S-adenosyl-L-methionine-dependent methyltransferase, Ecm18. The crystal structure of Ecm18 in complex with its reaction products S-adenosyl-L-homocysteine and echinomycin was determined at 1.50 Å resolution. Phasing was achieved using a new molecular replacement package called AMPLE, which automatically derives search models from structure predictions based on ab initio protein modelling. Structural analysis indicates that a combination of proximity effects, medium effects, and catalysis by strain drives the unique transformation of the disulfide bond into the thioacetal linkage.

Renewing Samsø

DEFF Research Database (Denmark)

Papazu, Irina

2017-01-01

and globally, I ask: if indeed such a process of renewal must be understood as a political process and the island’s energy transition as an inherently political event, what can Samsø teach us about the workings of politics and local democracy as enacted in practice? This is politics not as election result...... or ideological struggle over values, ideals and the distribution of goods, but as the down-to-earth but significant activity of creating something new together....

A kinetic and mechanistic study on the oxidation of l-methionine and N-acetyl l-methionine by cerium(IV) in sulfuric acid medium

OpenAIRE

T. Sumathi; P. Shanmugasundaram; G. Chandramohan

2016-01-01

The kinetics of oxidation of l-methionine and N-acetyl l-methionine by Ce(IV) in sulfuric acid–sulfate media in the range of 288.1–298.1 K has been investigated. The major oxidation products of methionine and N-acetyl l-methionine have been identified as methionine sulfoxide and N-acetyl methionine sulfoxide. The major oxidation products have been confirmed by qualitative analysis and boiling point. The reaction was first order with respect to l-methionine, N-acetyl l-methionine and Ce(IV). I...

Factors influencing methionine toxicity in young bobwhite quail

Science.gov (United States)

Serafin, J.A.

1981-01-01

Young Bobwhite quail (Colinus virginianus) were fed low and adequate protein purified diets with and without excess methionine to evaluate factors affecting methionine toxicity. Growth of quail fed an adequate protein (27%) diet, without supplemental glycine, was depressed by 1.75% and 2.25% excess methionine. Supplemental glycine (.3%) alleviated growth depression caused by 2.25% excess methionine. Quail fed 1.75% and 2.25% excess methionine developed signs of toxicity characterized by weakness, a lowered, outstretched neck when moving, and ataxia. In addition, quail would fall on their sides when disturbed and spin with their heads retracted. These conditions were transient in nature. Growth of quail fed a low protein (18.9%) diet was depressed by 1% and 1.5% excess methionine and DL-homocystine. Quail fed 1% and 1.5% excess methionine in this diet also developed signs of toxicity, the incidence of which was greater and the duration longer than occurred with quail fed adequate protein. Supplementing a low protein (20.15%) diet with .3% or .6% glycine or threonine or a combination of these amino acids did not alleviate growth depression caused by 1.5% excess methionine; however, 2% and 3% supplemental glycine were somewhat effective. Supplements of glycine (2%, 3%) and threonine (1%) completely reversed growth depression from 1% excess methionine but did not influence growth of controls, indicating that both amino acids counteract methionine toxicity. Both glycine and threonine alone improved growth by about the same extent in diets with 1% or 1.5% excess methionine; however, these amino acids alleviated less than 30% of the growth depression resulting from 1.5% excess methionine. The effectiveness of glycine in alleviating methionine toxicity in a low protein diet was decreased, and hemoglobin levels were depressed with 1.5% excess methionine compared to less amounts.

Efficacy of DL-methionine hydroxy analogue-free acid in comparison to DL-methionine in growing male white Pekin ducks.

Science.gov (United States)

Kluge, H; Gessner, D K; Herzog, E; Eder, K

2016-03-01

The present study was performed to assess the bioefficacy of DL-methionine hydroxy analogue-free acid (MHA) in comparison to DL-methionine (DLM) as sources of methionine for growing male white Pekin ducks in the first 3 wk of life. For this aim, 580 1-day-old male ducks were allocated into 12 treatment groups and received a basal diet that contained 0.29% of methionine, 0.34% of cysteine and 0.63% of total sulphur containing amino acids or the same diet supplemented with either DLM or MHA in amounts to supply 0.05, 0.10, 0.15, 0.20, and 0.25% of methionine equivalents. Ducks fed the control diet without methionine supplement had the lowest final body weights, daily body weight gains and feed intake among all groups. Supplementation of methionine improved final body weights and daily body weight gains in a dose dependent-manner. There was, however, no significant effect of the source of methionine on all of the performance responses. Evaluation of the data of daily body weight gains with an exponential model of regression revealed a nearly identical efficacy (slope of the curves) of both compounds for growth (DLM = 100%, MHA = 101%). According to the exponential model of regression, 95% of the maximum values of daily body weight gain were reached at methionine supplementary levels of 0.080% and 0.079% for DLM and MHA, respectively. Overall, the present study indicates that MHA and DLM have a similar efficacy as sources of methionine for growing ducks. It is moreover shown that dietary methionine concentrations of 0.37% are required to reach 95% of the maximum of daily body weight gains in ducks during the first 3 wk of life. © 2015 Poultry Science Association Inc.

Mutations in the histamine N-methyltransferase gene, HNMT, are associated with nonsyndromic autosomal recessive intellectual disability

OpenAIRE

Heidari, Abolfazl; Tongsook, Chanakan; Najafipour, Reza; Musante, Luciana; Vasli, Nasim; Garshasbi, Masoud; Hu, Hao; Mittal, Kirti; McNaughton, Amy J. M.; Sritharan, Kumudesh; Hudson, Melissa; Stehr, Henning; Talebi, Saeid; Moradi, Mohammad; Darvish, Hossein

2015-01-01

Histamine (HA) acts as a neurotransmitter in the brain, which participates in the regulation of many biological processes including inflammation, gastric acid secretion and neuromodulation. The enzyme histamine N-methyltransferase (HNMT) inactivates HA by transferring a methyl group from S-adenosyl-l-methionine to HA, and is the only well-known pathway for termination of neurotransmission actions of HA in mammalian central nervous system. We performed autozygosity mapping followed by targeted...

Determination of plasma adrenaline and noradrenaline levels with the Cat-a-Kit

International Nuclear Information System (INIS)

Nel, P.B.; Du Preez, S.E.

1980-01-01

A method for the determination of catecholamines (Cat-a-Kit; Upjohn Diagnostics) is discussed. It depends upon the enzymatic conversion of the catecholamines to their ring o-methylated analogues in the presence of s-adenosyl-L-methionine-methyl- 14 C and catechol-o-methyltransferase. Values obtained from the blood plasma of 16 tetraplegic and 11 healthy volunteers are reported. The advantages and disadvantages of the Cat-a-Kit are discussed

Development of miniature module for [11C] methionine synthesis

International Nuclear Information System (INIS)

Watanabe, Toshimitsu; Araya, Hiroshi; Ueno, Satoshi

2006-01-01

[ 18 F]FDG-PET has spread rapidly in the cancer diagnosis. On the other hand, [ 11 C]Methionine is paid attention as one of the PET drugs that may help cancer diagnosis by [ 18 F]FDG. Due to its short half-life, repeated preparations of [ 11 C] Methionine, two or three times a day, are generally required for the routine PET practice. Although the automatic synthesis devices for [ 11 C]Methionine were developed, it was difficult to supply [ 11 C]Methionine two times a day or more. We developed a methionine synthesis system that was able to supply [ 11 C]Methionine two times a day or more, and a new methionine synthesis unit. The new synthesis unit is able to synthesize [ 11 C]Methionine efficiently without HPLC preparation and evaporation in a short time. The new methionine synthesis unit and system are more useful for the routine synthesis of [ 11 C]Methionine. (author)

The effects of enhanced methionine synthesis on amino acid and anthocyanin content of potato tubers

Directory of Open Access Journals (Sweden)

Bánfalvi Zsófia

2008-06-01

Full Text Available Abstract Background Potato is a staple food in the diet of the world's population and also being used as animal feed. Compared to other crops, however, potato tubers are relatively poor in the essential amino acid, methionine. Our aim was to increase the methionine content of tubers by co-expressing a gene involved in methionine synthesis with a gene encoding a methionine-rich storage protein in potato plants. Results In higher plants, cystathionine γ-synthase (CgS is the first enzyme specific to methionine biosynthesis. We attempted to increase the methionine content of tubers by expressing the deleted form of the Arabidopsis CgS (CgSΔ90, which is not regulated by methionine, in potato plants. To increase the incorporation of free methionine into a storage protein the CgSΔ90 was co-transformed with the methionine-rich 15-kD β-zein. Results demonstrated a 2- to 6-fold increase in the free methionine content and in the methionine content of the zein-containing protein fraction of the transgenic tubers. In addition, in line with higher methionine content, the amounts of soluble isoleucine and serine were also increased. However, all of the lines with high level of CgSΔ90 expression were phenotypically abnormal showing severe growth retardation, changes in leaf architecture and 40- to 60% reduction in tuber yield. Furthermore, the colour of the transgenic tubers was altered due to the reduced amounts of anthocyanin pigments. The mRNA levels of phenylalanine ammonia-lyase (PAL, the enzyme catalysing the first step of anthocyanin synthesis, were decreased. Conclusion Ectopic expression of CgSΔ90 increases the methionine content of tubers, however, results in phenotypic aberrations in potato. Co-expression of the 15-kD β-zein with CgSΔ90 results in elevation of protein-bound methionine content of tubers, but can not overcome the phenotypical changes caused by CgSΔ90 and can not significantly improve the nutritional value of tubers. The level

Crystal structure of a new homochiral one-dimensional zincophosphate containing l-methionine

Directory of Open Access Journals (Sweden)

Nadjet Chouat

2015-07-01

Full Text Available catena-Poly[[(l-methionine-κOzinc]-μ3-(hydrogen phosphato-κ3O:O′:O′′], [Zn{PO3(OH}(C5H11NO2S]n, a new one-dimensional homochiral zincophosphate, was hydrothermally synthesized using l-methionine as a structure-directing agent. The compound consists of a network of ZnO4 and (HOPO3 tetrahedra that form ladder-like chains of edge-fused Zn2P2O4 rings propagating parallel to [100]. The chains are decorated on each side by zwitterionic l-methionine ligands, which interact with the inorganic framework via Zn—O coordination bonds. The structure displays interchain N—H...O and O—H...S hydrogen bonds.

Methionine metabolism and ethylene formation in etiolated pea stem sections

International Nuclear Information System (INIS)

Schilling, N.; Kende, H.

1979-01-01

Stem sections of etiolated pea seedlings (Pisum sativum L. cv. Alaska) were incubated overnight on tracer amounts of L-[U- 14 C]methionine and, on the following morning, on 0.1 millimolar indoleacetic acid to induce ethylene formation. Following the overnight incubation, over 70% of the radioactivity in the soluble fraction was shown to be associated with S-methylmethionine (SMM). The specific radioactivity of the ethylene evolved closely paralleled that of carbon atoms 3 and 4 of methionine extracted from the tissue and was always higher than that determined for carbon atoms 3 and 4 of extracted SMM. Overnight incubation of pea stem sections on 1 millimolar methionine enhanced indoleacetic acid-induced ethylene formation by 5 to 10%. Under the same conditions, 1 millimolar homocysteine thiolactone increased ethylene synthesis by 20 to 25%, while SMM within a concentration range of 0.1 to 10 millimolar did not influence ethylene production. When unlabeled methionine or homocysteine thiolactone was applied to stem sections which had been incubated overnight in L-[U- 14 C]methionine, the specific radioactivity of the ethylene evolved was considerably lowered. Application of unlabeled SMM reduced the specific radioactivity of ethylene only slightly

11C-methionine translocation in barley

International Nuclear Information System (INIS)

Nakanishi, Hiromi; Bughio, Naimatullah; Shigeta Ishioka, Noriko

2000-01-01

11 C-methionine was supplied to barley plants through a single leaf or via the roots and real time 11 C movement was monitored using a PETIS (positron emitting tracer imaging system). In Fe-deficient plants, 11 C-methionine was translocated from the tip of the absorbing leaf to the discrimination center' at the basal part of the shoot and then retranslocated to all the chlorotic leaves, while a negligible amount was retranslocated to the roots. In Fe-sufficient plants, methionine was translocated from the absorbing leaf to the discrimination center and then only to the newest leaf on the main shoot. A negligible amount was also retranslocated to the roots. Although, in Fe-sufficient plants, methionine translocation was observed from absorbing roots to shoots, in Fe-deficient plants, only a little amount was translocated from roots to shoots. In conclusion, methionine from the upper portion of a plant is not used as a precursor of mugineic acid under Fe-deficiency conditions. (author)

Cooperation between Magnesium and Metabolite Controls Collapse of the SAM-I Riboswitch.

Science.gov (United States)

Roy, Susmita; Onuchic, José N; Sanbonmatsu, Karissa Y

2017-07-25

The S-adenosylmethionine (SAM)-I riboswitch is a noncoding RNA that regulates the transcription termination process in response to metabolite (SAM) binding. The aptamer portion of the riboswitch may adopt an open or closed state depending on the presence of metabolite. Although the transition between the open and closed states is critical for the switching process, its atomistic details are not well understood. Using atomistic simulations, we calculate the effect of SAM and magnesium ions on the folding free energy landscape of the SAM-I riboswitch. These molecular simulation results are consistent with our previous wetlab experiments and aid in interpreting the SHAPE probing measurements. Here, molecular dynamics simulations explicitly identify target RNA motifs sensitive to magnesium ions and SAM. In the simulations, we observe that, whereas the metabolite mostly stabilizes the P1 and P3 helices, magnesium serves an important role in stabilizing a pseudoknot interaction between the P2 and P4 helices, even at high metabolite concentrations. The pseudoknot stabilization by magnesium, in combination with P1 stabilization by SAM, explains the requirement of both SAM and magnesium to form the fully collapsed metabolite-bound closed state of the SAM-I riboswitch. In the absence of SAM, frequent open-to-closed conformational transitions of the pseudoknot occur, akin to breathing. These pseudoknot fluctuations disrupt the binding site by facilitating fluctuations in the 5'-end of helix P1. Magnesium biases the landscape toward a collapsed state (preorganization) by coordinating pseudoknot and 5'-P1 fluctuations. The cooperation between SAM and magnesium in stabilizing important tertiary interactions elucidates their functional significance in transcription regulation. Published by Elsevier Inc.

Methionine sulfoxide profiling of milk proteins to assess the influence of lipids on protein oxidation in milk.

Science.gov (United States)

Wüst, Johannes; Pischetsrieder, Monika

2016-06-15

Thermal treatment of milk and milk products leads to protein oxidation, mainly the formation of methionine sulfoxide. Reactive oxygen species, responsible for the oxidation, can be generated by Maillard reaction, autoxidation of sugars, or lipid peroxidation. The present study investigated the influence of milk fat on methionine oxidation in milk. For this purpose, quantitative methionine sulfoxide profiling of all ten methionine residues of β-lactoglobulin, α-lactalbumin, and αs1-casein was carried out by ultrahigh-performance liquid chromatography-electrospray ionization tandem mass spectrometry with scheduled multiple reaction monitoring (UHPLC-ESI-MS/MS-sMRM). Analysis of defatted and regular raw milk samples after heating for up to 8 min at 120 °C and analysis of ultrahigh-temperature milk samples with 0.1%, 1.5%, and 3.5% fat revealed that methionine oxidation of the five residues of the whey proteins and of residues M 123, M 135, and M 196 of αs1-casein was not affected or even suppressed in the presence of milk fat. Only the oxidation of residues M 54 and M 60 of αs1-casein was promoted by lipids. In evaporated milk samples, formation of methionine sulfoxide was hardly influenced by the fat content of the samples. Thus, it can be concluded that lipid oxidation products are not the major cause of methionine oxidation in milk.

Samsø Energy Vision 2030

DEFF Research Database (Denmark)

Mathiesen, Brian Vad; Hansen, Kenneth; Ridjan, Iva

The purpose of this report is to investigate potential scenarios for converting Samsø into 100% renewable energy supply in 2030 with focus on local electricity and biomass resources. Firstly, a 2013 reference scenario is established to investigate whether Samsø is 100% renewable today. Next, scen...

System for Award Management (SAM) API

Data.gov (United States)

General Services Administration — The SAM API is a RESTful method of retrieving public information about the businesses, organizations, or individuals (referred to as entities) within the SAM entity...

Cognitive dysfunction in depression - pathophysiology and novel targets

DEFF Research Database (Denmark)

Carvalho, Andre F; Miskowiak, Kamilla Woznica; Hyphantis, Thomas N

2014-01-01

, inflammation (e.g., enhanced production of pro-inflammatory cytokines), mitochondrial dysfunction, increased apoptosis as well as a diminished neurotrophic support. Several promising neurotherapeutic targets were identified such as minocycline, statins, anti-inflammatory compounds, N-acetylcysteine, omega-3...... poliunsaturated fatty acids, erythropoietin, thiazolidinediones, glucagon-like peptide-1 analogues, S-adenosyl-l-methionine (SAMe), cocoa flavonols, creatine monohydrate and lithium. Erythropoietin and SAMe had pro-cognitive effects in randomized controlled trials (RCT) involving MDD patients. Despite having...

Changes in gene expression following androgen receptor blockade ...

Indian Academy of Sciences (India)

Madhu urs

of gene expression in the ventral prostate, it is not clear whether all the gene expression ... These include clusterin, methionine adenosyl transferase IIα, and prostate-specific ..... MAGEE1 melanoma antigen and no similarity was found with the ...

Activation of Nrf2 is required for up-regulation of the π class of glutathione S-transferase in rat primary hepatocytes with L-methionine starvation.

Science.gov (United States)

Lin, Ai-Hsuan; Chen, Haw-Wen; Liu, Cheng-Tze; Tsai, Chia-Wen; Lii, Chong-Kuei

2012-07-04

Numerous genes expression is regulated in response to amino acid shortage, which helps organisms adapt to amino acid limitation. The expression of the π class of glutathione (GSH) S-transferase (GSTP), a highly inducible phase II detoxification enzyme, is regulated mainly by activates activating protein 1 (AP-1) binding to the enhancer I of GSTP (GPEI). Here we show the critical role of nuclear factor erythroid-2-related factor 2 (Nrf2) in up-regulating GSTP gene transcription. Primary rat hepatocytes were cultured in a methionine-restricted medium, and immunoblotting and RT-PCR analyses showed that methionine restriction time-dependently increased GSTP protein and mRNA expression over a 48 h period. Nrf2 translocation to the nucleus, nuclear proteins binding to GPEI, and antioxidant response element (ARE) luciferase reporter activity were increased by methionine restriction as well as by l-buthionine sulfoximine (BSO), a GSH synthesis inhibitor. Transfection with Nrf2 siRNA knocked down Nrf2 expression and reversed the methionine-induced GSTP expression and GPEI binding activity. Chromatin immunoprecipitation assay confirmed the binding of Nrf2 to the GPEI. Phosphorylation of extracellular signal-regulated kinase 2 (ERK2) was increased in methionine-restricted and BSO-treated cells. ERK2 siRNA abolished methionine restriction-induced Nrf2 nuclear translocation, GPEI binding activity, ARE-luciferase reporter activity, and GSTP expression. Our results suggest that the up-regulation of GSTP gene transcription in response to methionine restriction likely occurs via the ERK-Nrf2-GPEI signaling pathway.

78 FR 62627 - Sam Rayburn Dam Rate

Science.gov (United States)

2013-10-22

..., Wholesale Rates for Hydro Power and Energy Sold to Sam Rayburn Dam Electric Cooperative, Inc. (Contract No... Schedule SRD-08, Wholesale Rates for Hydro Power and Energy Sold to Sam Rayburn Dam Electric Cooperative... ADMINISTRATION RATE SCHEDULE SRD-13 \\1\\ WHOLESALE RATES FOR HYDRO POWER AND ENERGY SOLD TO SAM RAYBURN DAM...

Methionine kinetics in adult men: effects of dietary betaine on L-[2H3-methyl-1-13C]methionine

International Nuclear Information System (INIS)

Storch, K.J.; Wagner, D.A.; Young, V.R.

1991-01-01

The effects of a daily 3-g supplement of betaine on kinetic aspects of L-[2H3-methyl-1-13C]methionine (MET) metabolism in healthy young adult men were explored. Four groups of four subjects each were given a control diet, based on an L-amino acid mixture supplying 29.5 and 21.9 mg.kg-1.d-1 of L-methionine and L-cystine for 4 d before the tracer study, conducted on day 5 during the fed state. Two groups received the control diet and two groups received the betaine supplement. Tracer was given intravenously (iv) or orally. The transmethylation rate of MET (TM), homocysteine remethylation (RM), and oxidation of methionine were estimated from plasma methionine labeling and 13C enrichment of expired air. RM tended to increase (P = 0.14) but the TM and methionine oxidation were significantly (P less than 0.05) higher after betaine supplementation when estimated with the oral tracer. No differences were detected with the intravenous tracer. Methionine concentration in plasma obtained from blood taken from subjects in the fed state was higher (P less than 0.01) with betaine supplementation. These results suggest that excess methyl-group intake may increase the dietary requirement for methionine

Methionine sulphoxide reductases revisited: free methionine as a primary target of H2O2 stress in auxotrophic fission yeast

OpenAIRE

García Santamarina, Sarela, 1978-; Boronat i Llop, Susanna, 1965-; Ayté del Olmo, José; Hidalgo Hernando, Elena

2013-01-01

Amino acid methionine can suffer reversible oxidation to sulphoxide and further irreversible over-oxidation to methionine sulphone. As part of the cellular antioxidant scavenging activities are the methionine sulphoxide reductases (Msrs), with a reported role in methionine sulphoxide reduction, both free and in proteins. Three families of Msrs have been described, but the fission yeast genome only includes one representative for two of these families: MsrA/Mxr1 and MsrB/Mxr2. We have investig...

A felkelés éghajlata: Sam White környezettörténeti elmélete az Oszmán Birodalom hanyatlásáról - The Climate of Rebellion: Sam White’s Environmental Theory about the Decline of the Ottoman Empire

Directory of Open Access Journals (Sweden)

RÁCZ, Lajos

2014-09-01

Full Text Available The book of Sam White has offered a new interpretation of Ottoman history from the 16th to the 18th centuries. The American author has argued that historians have to consider the ecological conditions of the early modern Near East and the profound impacts and repercussions of the Little Ice Age in order to understand the empire’s successes, crises and transformations. White’s study presents the expansive ‘imperial ecology’ underlying the rapid expansion in the classical age which made the empire increasingly vulnerable to war and natural disasters as the population pressure set in in the late 1500s. Sam White examined the impact of Little Ice Age and climatic fluctuation from the late 16th through the early 18th centuries, demonstrating the strong links between extreme climatic events and the outbreak of the Celali Rebellion and the recurring disorders of the 1600s. Finally, the author argued that transformations in human ecology – particularly the spread of nomadic pastoralism, migration to urban areas, and a shift to new crops for commerce and exports – slowed the demographic recovery of Ottoman lands, leaving the empire relatively depopulated by the mid-19th century.

Novel double-isotope technique for enzymatic assay of catecholamines, permitting high precision, sensitivity and plasma sample capacity

International Nuclear Information System (INIS)

Brown, M.J.; Jenner, D.A.

1981-01-01

A novel use of a double-isotope method is described which allows radioenzymatic assays to combine precision and sensitivity. In the catechol O-methyltransferase assay separate portions of each plasma sample are incubated with either S-[ 3 H]- or S-[ 14 C]-adenosyl-L-methionine. Standards of noradrenaline and adrenaline are added to the latter portions and are thus converted into standards of [ 14 C]metadrenalines. These are added to the 3 H-labelled portions after the incubation, where they function as tracers. The final recovery of 14 C radioactivity corrects for (a) the efficiency of methylation in the plasma sample concerned and (b) the recovery of metadrenalines during the extraction procedures. The 3 H/ 14 C ratio is constant in each assay for a given catecholamine concentration and is determined for samples to which standards of noradrenaline and adrenaline are added to the 3 H- (as well as the 14 C-) labelled portions before the initial incubation. The sensitivity of the assay is increased by using high specific radioactivity S-[ 3 H]adenosyl-L-methionine, and low backgrounds are maintained by catecholamine depletion in vivo in the rats used for enzyme preparation. Both catecholamines (1.5 pg/ml; 10 pmol/l) may be detected; the coefficients of variation are 3.0 and 3.2% for noradrenaline and adrenaline respectively (intra-assay) and 4.6 and 5.0% (inter-assay). (author)

Crystal structures of human 108V and 108M catechol O-methyltransferase

Energy Technology Data Exchange (ETDEWEB)

Rutherford, K.; Le Trong, I.; Stenkamp, R.E.; Parson, W.W. (UWASH)

2008-08-01

Catechol O-methyltransferase (COMT) plays important roles in the metabolism of catecholamine neurotransmitters and catechol estrogens. The development of COMT inhibitors for use in the treatment of Parkinson's disease has been aided by crystallographic structures of the rat enzyme. However, the human and rat proteins have significantly different substrate specificities. Additionally, human COMT contains a common valine-methionine polymorphism at position 108. The methionine protein is less stable than the valine polymorph, resulting in decreased enzyme activity and protein levels in vivo. Here we describe the crystal structures of the 108V and 108M variants of the soluble form of human COMT bound with S-adenosylmethionine (SAM) and a substrate analog, 3,5-dinitrocatechol. The polymorphic residue 108 is located in the {alpha}5-{beta}3 loop, buried in a hydrophobic pocket {approx}16 {angstrom} from the SAM-binding site. The 108V and 108M structures are very similar overall [RMSD of C{sup {alpha}} atoms between two structures (C{sup {alpha}} RMSD) = 0.2 {angstrom}], and the active-site residues are superposable, in accord with the observation that SAM stabilizes 108M COMT. However, the methionine side chain is packed more tightly within the polymorphic site and, consequently, interacts more closely with residues A22 ({alpha}2) and R78 ({alpha}4) than does valine. These interactions of the larger methionine result in a 0.7-{angstrom} displacement in the backbone structure near residue 108, which propagates along {alpha}1 and {alpha}5 toward the SAM-binding site. Although the overall secondary structures of the human and rat proteins are very similar (C{sup {alpha}} RMSD = 0.4 {angstrom}), several nonconserved residues are present in the SAM-(I89M, I91M, C95Y) and catechol- (C173V, R201M, E202K) binding sites. The human protein also contains three additional solvent-exposed cysteine residues (C95, C173, C188) that may contribute to intermolecular disulfide bond

Identification and Analysis of the SET-Domain Family in Silkworm, Bombyx mori

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Hailong Zhao

2015-01-01

Full Text Available As an important economic insect, Bombyx mori is also a useful model organism for lepidopteran insect. SET-domain-containing proteins belong to a group of enzymes named after a common domain that utilizes the cofactor S-adenosyl-L-methionine (SAM to achieve methylation of its substrates. Many SET-domain-containing proteins have been shown to display catalytic activity towards particular lysine residues on histones, but emerging evidence also indicates that various nonhistone proteins are specifically targeted by this clade of enzymes. To explore their diverse functions of SET-domain superfamily in insect, we identified, cloned, and analyzed the SET-domains proteins in silkworm, Bombyx mori. Firstly, 24 genes containing SET domain from silkworm genome were characterized and 17 of them belonged to six subfamilies of SUV39, SET1, SET2, SUV4-20, EZ, and SMYD. Secondly, SET domains of silkworm SET-domain family were intraspecifically and interspecifically conserved, especially for the catalytic core “NHSC” motif, substrate binding site, and catalytic site in the SET domain. Lastly, further analyses indicated that silkworm SET-domain gene BmSu(var3-9 owned different characterization and expression profiles compared to other invertebrates. Overall, our results provide a new insight into the functional and evolutionary features of SET-domain family.

Identification and molecular characterization of the nicotianamine synthase gene family in bread wheat.

Science.gov (United States)

Bonneau, Julien; Baumann, Ute; Beasley, Jesse; Li, Yuan; Johnson, Alexander A T

2016-12-01

Nicotianamine (NA) is a non-protein amino acid involved in fundamental aspects of metal uptake, transport and homeostasis in all plants and constitutes the biosynthetic precursor of mugineic acid family phytosiderophores (MAs) in graminaceous plant species. Nicotianamine synthase (NAS) genes, which encode enzymes that synthesize NA from S-adenosyl-L-methionine (SAM), are differentially regulated by iron (Fe) status in most plant species and plant genomes have been found to contain anywhere from 1 to 9 NAS genes. This study describes the identification of 21 NAS genes in the hexaploid bread wheat (Triticum aestivum L.) genome and their phylogenetic classification into two distinct clades. The TaNAS genes are highly expressed during germination, seedling growth and reproductive development. Fourteen of the clade I NAS genes were up-regulated in root tissues under conditions of Fe deficiency. Protein sequence analyses revealed the presence of endocytosis motifs in all of the wheat NAS proteins as well as chloroplast, mitochondrial and secretory transit peptide signals in four proteins. These results greatly expand our knowledge of NAS gene families in graminaceous plant species as well as the genetics underlying Fe nutrition in bread wheat. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Proteome Remodeling in Response to Sulfur Limitation in “ Candidatus Pelagibacter ubique”

Energy Technology Data Exchange (ETDEWEB)

Smith, Daniel P.; Nicora, Carrie D.; Carini, Paul; Lipton, Mary S.; Norbeck, Angela D.; Smith, Richard D.; Giovannoni, Stephen J.; Wilmes, Paul

2016-07-12

The alphaproteobacterium “CandidatusPelagibacter ubique” strain HTCC1062 and most other members of the SAR11 clade lack genes for assimilatory sulfate reduction, making them dependent on organosulfur compounds that occur naturally in seawater. To investigate how these cells adapt to sulfur limitation, batch cultures were grown in defined medium containing either limiting or nonlimiting amounts of dimethylsulfoniopropionate (DMSP) as the sole sulfur source. Protein and mRNA expression were measured before, during, and after the transition from exponential growth to stationary phase. Two distinct responses were observed, one as DMSP became exhausted and another as the cells acclimated to a sulfur-limited environment. The first response was characterized by increased transcription and translation of all “Ca. Pelagibacter ubique” genes downstream from the previously confirmedS-adenosyl methionine (SAM) riboswitchesbhmT,mmuM, andmetY. The proteins encoded by these genes were up to 33 times more abundant as DMSP became limiting. Their predicted function is to shunt all available sulfur to methionine. The secondary response, observed during sulfur-limited stationary phase, was a 6- to 10-fold increase in the transcription of the hemecshuttle-encoding geneccmCand two small genes of unknown function (SAR11_1163andSAR11_1164). This bacterium’s strategy for coping with sulfur stress appears to be intracellular redistribution to support methionine biosynthesis rather than increasing organosulfur import. Many of the genes and SAM riboswitches involved in this response are located in a hypervariable genome region (HVR). One of these HVR genes,ordL, is located downstream from a conserved motif that evidence suggests is a novel riboswitch.

A kinetic and mechanistic study on the oxidation of l-methionine and N-acetyl l-methionine by cerium(IV in sulfuric acid medium

Directory of Open Access Journals (Sweden)

T. Sumathi

2016-09-01

Full Text Available The kinetics of oxidation of l-methionine and N-acetyl l-methionine by Ce(IV in sulfuric acid–sulfate media in the range of 288.1–298.1 K has been investigated. The major oxidation products of methionine and N-acetyl l-methionine have been identified as methionine sulfoxide and N-acetyl methionine sulfoxide. The major oxidation products have been confirmed by qualitative analysis and boiling point. The reaction was first order with respect to l-methionine, N-acetyl l-methionine and Ce(IV. Increase in [H+], ionic strength and HSO4- did not affect the reaction rate. Under the experimental conditions, Ce4+ was the effective oxidizing species of cerium. Increase in dielectric constant of the medium decreased the reaction rate. Under nitrogen atmosphere, the reaction system can initiate polymerization of acrylonitrile, indicating the generation of free radicals. Activation parameters associated with the overall reaction have been calculated.

Safety of methionine, a novel biopesticide, to adult and larval honey bees (Apis mellifera L.).

Science.gov (United States)

Weeks, Emma N I; Schmehl, Daniel R; Baniszewski, Julie; Tomé, Hudson V V; Cuda, James P; Ellis, James D; Stevens, Bruce R

2018-03-01

Methionine is an essential/indispensible amino acid nutrient required by adult and larval honey bees (Apis mellifera L. [Hymenoptera: Apidae]). Bees are unable to rear broods on pollen deficient in methionine, and reportedly behaviorally avoid collecting pollen or nectar from florets deficient in methioinine. In contrast, it has been demonstrated that methionine is toxic to certain pest insects; thus it has been proposed as an effective biopesticide. As an ecofriendly integrated pest management agent, methionine boasts a novel mode of action differentiating it from conventional pesticides, while providing non-target safety. Pesticides that minimize collateral effects on bees are desirable, given the economic and ecological concerns about honey bee health. The aim of the present study was to assess the potential impact of the biopesticide methionine on non-target adult and larval honey bees. Acute contact adult toxicology bioassays, oral adult assessments and chronic larval toxicity assessments were performed as per U.S. Environmental Protection Agency (EPA) requirements. Our results demonstrated that methionine fits the U.S. EPA category of practically nontoxic (i.e. lethal dose to 50% mortality or LD 50 > 11µg/bee) to adult honey bees. The contact LD 50 was > 25µg/bee and the oral LD 50 was > 100µg/bee. Mortality was observed in larval bees that ingested DL-methionine (effective concentration to 50% mortality or EC 50 560µg/bee). Therefore, we conclude that methionine poses little threat to the health of the honey bee, due to unlikely exposure at concentrations shown to elicit toxic effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Data handling with SAM and art at the NOνA experiment

International Nuclear Information System (INIS)

Aurisano, A; Backhouse, C; Davies, G S; Illingworth, R; Mengel, M; Norman, A; Mayer, N; Rocco, D; Zirnstein, J

2015-01-01

During operations, NOvA produces between 5,000 and 7,000 raw files per day with peaks in excess of 12,000. These files must be processed in several stages to produce fully calibrated and reconstructed analysis files. In addition, many simulated neutrino interactions must be produced and processed through the same stages as data. To accommodate the large volume of data and Monte Carlo, production must be possible both on the Fermilab grid and on off-site farms, such as the ones accessible through the Open Science Grid. To handle the challenge of cataloging these files and to facilitate their off-line processing, we have adopted the SAM system developed at Fermilab. SAM indexes files according to metadata, keeps track of each file's physical locations, provides dataset management facilities, and facilitates data transfer to off-site grids. To integrate SAM with Fermilab's art software framework and the NOvA production workflow, we have developed methods to embed metadata into our configuration files, art files, and standalone ROOT files. A module in the art framework propagates the embedded information from configuration files into art files, and from input art files to output art files, allowing us to maintain a complete processing history within our files. Embedding metadata in configuration files also allows configuration files indexed in SAM to be used as inputs to Monte Carlo production jobs. Further, SAM keeps track of the input files used to create each output file. Parentage information enables the construction of self-draining datasets which have become the primary production paradigm used at NOvA. In this paper we will present an overview of SAM at NOvA and how it has transformed the file production framework used by the experiment. (paper)

LuxS impacts on LytA-dependent autolysis and on competence in Streptococcus pneumoniae.

Science.gov (United States)

Romao, Susana; Memmi, Guido; Oggioni, Marco R; Trombe, Marie-Claude

2006-02-01

The ubiquitous protein LuxS with S-ribosylhomocysteinase activity is involved in S-adenosyl methionine detoxification, C-1 unit recycling and the production of autoinducers that allow the cell to sense and respond to cell density. Independent reports describe the impact of LuxS deficiency on Streptococcus pneumoniae virulence in the mouse. In vitro, LuxS deficiency confers discrete phenotypes. A combined approach using genetic dissection and mixed-culture experiments allowed the involvement of LuxS in the developmental physiology of S. pneumoniae to be investigated. Functional LuxS was found to be related on the one hand to down-regulation of competence, and on the other hand to attenuation of autolysis in cultures entering stationary phase. The competence phenotype of luxS mutant bacteria was complemented by media conditioned by competence-defective ComAB0 bacteria, but not by BSA. The autolytic phenotype was complemented by BSA, but not by conditioned supernatants. It is suggested that the impact of LuxS on competence, but not on autolysis, involves cell-cell communication. The phenotype of luxS mutant strains reveals a hierarchy in the competence regulatory networks of S. pneumoniae.

Expression of methionine adenosyltransferase 2A in renal cell carcinomas and potential mechanism for kidney carcinogenesis

International Nuclear Information System (INIS)

Wang, Xuliang; Guo, Xiaoqiang; Yu, Wenshui; Li, Cailing; Gui, Yaoting; Cai, Zhiming

2014-01-01

Methionine adenosyltransferase 2A (MAT2A) is an enzyme that catalyzes the formation of S-adenosylmethionine (SAMe) by joining methionine and ATP. SAMe is a methyl donor for transmethylation and has an important role for DNA and/or protein methylation. MAT2A is expressed widely in many tissues especially in kidney. Several studies have demonstrated that there are abnormal expressions of MAT2A in several kinds of cancers such as liver and colon cancers. But the relationship of MAT2A between renal cell carcinomas (RCC) is less understood. The mRNA expression level of the MAT2A gene was determined in 24 RCC patients and 4 RCC cell lines, using real-time quantitative-polymerase chain reaction (RT-PCR). The MAT2A protein content was measured by western blotting and immunohistochemical analysis in 55 RCC patients. The mRNA levels of heme oxygenase-1 (HO-1) and cyclooxygenase-2 (COX-2) were also analysized in patients using RT-PCR. The correlations between the MAT2A and HO-1 as well as COX-2 were analyzed with nonparametric Spearman method. MAT2A transcript was significantly downregulated in cancer tissues compared to normal tissues (P < 0.05). Immunohistochemical analysis and western blotting indicated that level of MAT2A protein was decreased in cancer tissues. The statistical analysis reveals a negative correlation between MAT2A and HO-1 expression in RCC patients and cell lines (P < 0.01). This study demonstrated that MAT2A was lower expression in cancer tissues, suggesting that it may be involved in the development of RCC. MAT2A is a transcriptional corepressor for HO-1 expression by supplying SAM for methyltransferases, which may be one of potential mechanism of MAT2A as tumor suppressor in kidney carcinogenesis

Betaine is as effective as folate at re-synthesizing methionine for protein synthesis during moderate methionine deficiency in piglets.

Science.gov (United States)

McBreairty, Laura E; Robinson, Jason L; Harding, Scott V; Randell, Edward W; Brunton, Janet A; Bertolo, Robert F

2016-12-01

Both folate and betaine (synthesized from choline) are nutrients used to methylate homocysteine to reform the amino acid methionine following donation of its methyl group; however, it is unclear whether both remethylation pathways are of equal importance during the neonatal period when remethylation rates are high. Methionine is an indispensable amino acid that is in high demand in neonates not only for protein synthesis, but is also particularly important for transmethylation reactions, such as creatine and phosphatidylcholine synthesis. The objective of this study was to determine whether supplementation with folate, betaine, or a combination of both can equally re-synthesize methionine for protein synthesis when dietary methionine is limiting. Piglets were fed a low methionine diet devoid of folate, choline, and betaine, and on day 6, piglets were supplemented with either folate, betaine, or folate + betaine (n = 6 per treatment) until day 10. [1- 13 C]-phenylalanine oxidation was measured as an indicator of methionine availability for protein synthesis both before and after 2 days of supplementation. Prior to supplementation, piglets had lower concentrations of plasma folate, betaine, and choline compared to baseline with no change in homocysteine. Post-supplementation, phenylalanine oxidation levels were 20-46 % lower with any methyl donor supplementation (P = 0.006) with no difference among different supplementation groups. Furthermore, both methyl donors led to similarly lower concentrations of homocysteine following supplementation (P folate to remethylate methionine for protein synthesis, as indicated by lower phenylalanine oxidation.

Metabolic Regulation of Methionine Restriction in Diabetes.

Science.gov (United States)

Yin, Jie; Ren, Wenkai; Chen, Shuai; Li, Yuying; Han, Hui; Gao, Jing; Liu, Gang; Wu, Xin; Li, Tiejun; Kim, Sung Woo; Yin, Yulong

2018-03-30

Although the effects of dietary methionine restriction have been investigated in the physiology of aging and diseases related to oxidative stress, the relationship between methionine restriction and the development of metabolic disorders has not been explored extensively. This review summarizes studies of the possible involvement of dietary methionine restriction in improving insulin resistance, glucose homeostasis, oxidative stress, lipid metabolism, the pentose phosphate pathway, and inflammation, with an emphasis on the fibroblast growth factor 21 and protein phosphatase 2A signals and autophagy in diabetes. Diets deficient in methionine may be a useful nutritional strategy in patients with diabetes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Folate (vitamin B9) and vitamin B12 and their function in the maintenance of nuclear and mitochondrial genome integrity

Energy Technology Data Exchange (ETDEWEB)

Fenech, Michael, E-mail: michael.fenech@csiro.au [CSIRO Food and Nutritional Sciences, PO Box 10041 Adelaide BC, SA 5000 (Australia)

2012-05-01

Folate plays a critical role in the prevention of uracil incorporation into DNA and hypomethylation of DNA. This activity is compromised when vitamin B12 concentration is low because methionine synthase activity is reduced, lowering the concentration of S-adenosyl methionine (SAM) which in turn may diminish DNA methylation and cause folate to become unavailable for the conversion of dUMP to dTMP. The most plausible explanation for the chromosome-breaking effect of low folate is excessive uracil misincorporation into DNA, a mutagenic lesion that leads to strand breaks in DNA during repair. Both in vitro and in vivo studies with human cells clearly show that folate deficiency causes expression of chromosomal fragile sites, chromosome breaks, excessive uracil in DNA, micronucleus formation, DNA hypomethylation and mitochondrial DNA deletions. In vivo studies show that folate and/or vitamin B12 deficiency and elevated plasma homocysteine (a metabolic indicator of folate deficiency) are significantly correlated with increased micronucleus formation and reduced telomere length respectively. In vitro experiments indicate that genomic instability in human cells is minimised when folic acid concentration in culture medium is greater than 100 nmol/L. Intervention studies in humans show (a) that DNA hypomethylation, chromosome breaks, uracil incorporation and micronucleus formation are minimised when red cell folate concentration is greater than 700 nmol/L and (b) micronucleus formation is minimised when plasma concentration of vitamin B12 is greater than 300 pmol/L and plasma homocysteine is less than 7.5 {mu}mol/L. These concentrations are achievable at intake levels at or above current recommended dietary intakes of folate (i.e. >400 {mu}g/day) and vitamin B12 (i.e. >2 {mu}g/day) depending on an individual's capacity to absorb and metabolise these vitamins which may vary due to genetic and epigenetic differences.

New metabolic labelling medium for Trichomonas vaginalis and Tritrichomonas foetus using 35S methionine

Energy Technology Data Exchange (ETDEWEB)

Torian, B.E.; Kenny, G.E.

1986-04-01

A metabolic labelling medium was devised for Trichomonas vaginalis and Tritrichomonas foetus utilizing 35S methionine. T. vaginalis cultured for 24h in the medium took up approximately 27% of the available label and increased greater than two fold in number. Counts per microgram of protein were 32,555 +/- 10% between different strains or identical strains in different labelling runs. T. foetus took up approximately 5% of the available label and increased greater than two fold in 24h. This resulted in specific labelling of 12,704 cpm/ug protein +/- 10% between different runs with the same strain.

New metabolic labelling medium for Trichomonas vaginalis and Tritrichomonas foetus using 35S methionine

International Nuclear Information System (INIS)

Torian, B.E.; Kenny, G.E.

1986-01-01

A metabolic labelling medium was devised for Trichomonas vaginalis and Tritrichomonas foetus utilizing 35S methionine. T. vaginalis cultured for 24h in the medium took up approximately 27% of the available label and increased greater than two fold in number. Counts per microgram of protein were 32,555 +/- 10% between different strains or identical strains in different labelling runs. T. foetus took up approximately 5% of the available label and increased greater than two fold in 24h. This resulted in specific labelling of 12,704 cpm/ug protein +/- 10% between different runs with the same strain

Optimization of pentacene double floating gate memories based on charge injection regulated by SAM functionalization

Directory of Open Access Journals (Sweden)

S. Li

2018-02-01

Full Text Available Pentacene based double nano-floating gate memories (NFGM by using gold nanoparticles (Au NPs and reduced graphene oxide (rGO sheets as charge trapping layers are prepared and demonstrated. Particularly, the NFGM chemically treated by 2,3,4,5,6-pentafluorobenzenethiol (PFBT self-assembled monolayers (SAM exhibits excellent memory performances, including high mobility of 0.23 cm2V-1s-1, the large memory window of 51 V, and the stable retention property more than 108 s. Comparing the performances of NFGM without treating with PFBT SAM, the improving performances of the memory devices by SAM modification are explained by the increase of charge injection, which could be further investigated by XPS and UPS. In particular, the results highlight the utility of SAM modulations and controlling of charge transport in the development of organic transistor memories.

Optimization of pentacene double floating gate memories based on charge injection regulated by SAM functionalization

Science.gov (United States)

Li, S.; Guérin, D.; Lenfant, S.; Lmimouni, K.

2018-02-01

Pentacene based double nano-floating gate memories (NFGM) by using gold nanoparticles (Au NPs) and reduced graphene oxide (rGO) sheets as charge trapping layers are prepared and demonstrated. Particularly, the NFGM chemically treated by 2,3,4,5,6-pentafluorobenzenethiol (PFBT) self-assembled monolayers (SAM) exhibits excellent memory performances, including high mobility of 0.23 cm2V-1s-1, the large memory window of 51 V, and the stable retention property more than 108 s. Comparing the performances of NFGM without treating with PFBT SAM, the improving performances of the memory devices by SAM modification are explained by the increase of charge injection, which could be further investigated by XPS and UPS. In particular, the results highlight the utility of SAM modulations and controlling of charge transport in the development of organic transistor memories.

The Performance of CSAM SAM when Cycle Length is extended

Energy Technology Data Exchange (ETDEWEB)

Roh, Kyung-ho; Moon, Sang-rae [KHNP, Daejeon (Korea, Republic of)

2016-10-15

In order to verify validation of that, CPC Axial Power Distribution is compared with Axial Power Distribution based on ICI every week. The difference between CPC Axial Power Distribution and Axial Power Distribution based on ICI increases according as fuels are burned. It is called CPC Axial Power Distribution Root Mean Square Error (CPC RMS Error). SAM and calibration of ex-core detector are important factors influencing the magnitude of the difference. According to vendor, the difference is limited by 8%. Otherwise, CPC penalty increases as many as difference increase. Therefore, KHNP developed Constrained Simulated Annealing Method (CSAM), which has better performance than that of Least Square Method (LSM), to calculate SAM constant. The CSA SAM contributed largely to maintain CPC operating margin. Somewhat, KHNP is developing the technology to be able to operate nuclear power plants for 24 month to optimize their efficiency. This paper shows trends of CPC RMS Error in a case of 24 months operation. Trends are based on data of a few OPR1000s under operation. It is data of OPR1000s that CSA SAM is applied. KHNP is developing the technology to extend operation cycle length in order to optimize the operation efficiency of OPR1000. To verify effect of extended operation cycle length on CPC, CPC Axial Power Distribution RMS Error in a case of 24 months operation was expected using operation data of six cycles in OPR1000. In cases that CPC Axial Power Distribution RMS Error exceeds threshold, operation margin is decreased due to CPC penalty. To prevent CPC operation margin from being decreased, improved method to calculate SAM or to calibrate ex-core detector is required. KHNP will consider the way to maintain CPC operation margin along with 24 month operation technology development, hereafter.

核蛋白Sam68的原核表达及鉴定%Prokaryotic Expression and Identification of Nuclear Protein Sam68

Institute of Scientific and Technical Information of China (English)

张华; 陈宁; 丁筠; 邹德华; 潘子夜; 李鹏飞; 李丽阳; 肖丽杰; 曹宏伟

2017-01-01

为了构建pGEX-4T-1-Sam68原核表达载体,表达并鉴定GST-Sam68融合蛋白,采用PCR扩增Sam68基因,插入pGEX-4T-1的EcoR I和Sal I位点,并转化Rosetta(DE3)大肠杆菌,IPTG诱导表达,SDS-PAGE和Western Blot验证蛋白表达,GST pull-down技术验证Sam68的结合活性.酶切和测序结果证实Sam68基因正确插入pGEX-4T-1载体中,载体能够在Rosetta(DE3)细胞中正确表达,且纯化的GST-Sam68蛋白具有与PI3K p85特异结合的活性,说明成功构建了原核表达载体pGEX-4T-1-Sam68.

The First International Mini-Symposium on Methionine Restriction and Lifespan

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Gene eAbles

2014-05-01

Full Text Available It has been 20 years since the Orentreich Foundation for the Advancement of Science, under the leadership Dr. Norman Orentreich, first reported that low methionine (Met ingestion by rats extends lifespan [1]. Since then, several studies have replicated the effects of dietary methionine restriction (MR in delaying age-related diseases [2–5]. We report the abstracts from the First International Mini-Symposium on Methionine Restriction and Lifespan held in Tarrytown, NY last September 2013. The goals were 1 to gather researchers with an interest in methionine restriction and lifespan, 2 to exchange knowledge, 3 to generate ideas for future investigations, and 4 to strengthen relationships within this community. The presentations highlighted the importance of research on cysteine, growth hormone (GH, and ATF4 in the paradigm of aging. In addition, the effects of dietary restriction or MR in the kidneys, liver, bones and the adipose tissue were discussed. The symposium also emphasized the value of other species, e.g. the naked mole rat, Brandt’s bat and drosophila in aging research. Overall, the symposium consolidated scientists with similar research interests and provided opportunities to conduct future collaborative studies.

Bringing a Chemical Laboratory Named Sam to Mars on the 2011 Curiosity Rover

Science.gov (United States)

Mahaffy, P. R.; Bleacher, L.; Jones, A.; Atreya, S. K.; Manning, H. L.; Cabane, M.; Webster, C. R.; Sam Team

2010-12-01

Introduction: An important goal of upcoming missions to Mars is to understand if life could have developed there. The task of the Sample Analysis at Mars (SAM) suite of instruments [1] and the other Curiosity investigations [2] is to move us steadily toward that goal with an assessment of the habitability of our neighboring planet through a series of chemical and geological measurements. SAM is designed to search for organic compounds and inorganic volatiles and measure isotope ratios. Other instruments on Curiosity will provide elemental analysis and identify minerals. SAM will analyze both atmospheric samples and gases evolved from powdered rocks that may have formed billions of years ago with Curiosity providing access to interesting sites scouted by orbiting cameras and spectrometers. SAM Instrument Suite: SAM’s instruments are a Quadrupole Mass Spectrometer (QMS), a 6-column Gas Chromatograph (GC), and a 2-channel Tunable Laser Spectrometer (TLS). SAM can identify organic compounds in Mars rocks to sub-ppb sensitivity and secure precise isotope ratios for C, H, and O in carbon dioxide and water and measure trace levels of methane and its carbon 13 isotope. The SAM gas processing system consists of valves, heaters, pressure sensors, gas scrubbers and getters, traps, and gas tanks used for calibration or combustion experiments [2]. A variety of calibrant compounds interior and exterior to SAM will allow the science and engineering teams to assess SAM’s performance. SAM has been calibrated and tested in a Mars-like environment. Keeping Educators and the Public Informed: The Education and Public Outreach (EPO) goals of the SAM team are to make this complex chemical laboratory and its data widely available to educators, students, and the public. Formal education activities include developing templates for professional development workshops for educators to teach them about SAM and Curiosity, incorporating data into Mars Student Data Teams, and writing articles

Orientation of 6-mercaptopurine SAMs at the silver electrode as studied by Raman mapping and in situ SERS.

Science.gov (United States)

Chu, Hui; Yang, Haifeng; Huan, Shuangyan; Shen, Guoli; Yu, Ruqin

2006-03-23

Self-assembled monolayers (SAMs) of 6-mercaptopurine (6MP) on a silver electrode in acid and alkaline media were investigated by a combination protocol of the SERS technique with Raman mapping, and it was found that the adsorption mode of 6MP SAMs changed with the pH value of the environment. Quantum calculations for the vibrational mode were performed by the BLYP/6-31G method. 6MP was adsorbed on the silver electrode with a tilted orientation via S, N1, and N7 atoms in acid medium, while the SAMs adopted head-on adsorption modes with the S atom and the N1 atom anchoring the silver surface in alkaline medium. However, 6MP SAMs turned to the same upright orientation on the electrode through the S and N7 atoms when either acid or basic solution was removed. Stability of 6MP SAMs was observed by in situ SERS spectroelectrochemical measurements. The results reveal that the desorption potentials of 6MP SAMs formed under acid and alkaline conditions from the Ag electrode were at ca. -1.3 V and -1.6 V vs SCE, respectively.

Cadmium toxicity induced contrasting patterns of concentrations of free sarcosine, specific amino acids and selected microelements in two Noccaea species

Czech Academy of Sciences Publication Activity Database

Zemanová, Veronika; Pavlík, Milan; Pavlíková, D.

2017-01-01

Roč. 12, č. 5 (2017), č. článku e0177963. E-ISSN 1932-6203 Institutional support: RVO:61389030 Keywords : ADENOSYL-L-METHIONINE * ABIOTIC STRESS * GLYCINE BETAINE Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 2.806, year: 2016

Methylation of nucleolar RNA in HeLa cells studied by autoradiography

International Nuclear Information System (INIS)

Cervera, J.; Martinez, A.; Renau-Piqueras, J.

1984-01-01

Methylation of nucleolar RNA was studied by autoradiography in HeLa cells using L-[methyl- 3 H]methionine and S-adenosyl-L-[methyl- 3 H]methionine as radioactive precursors. Pulse-labeling experiments show that nucleolar RNA methylation occurs on the newly synthesized RNA at the nucleolar fibrillar RNP component and mostly on the fibrillar ring of fibrillar centers, where pre-rRNA is being synthesized. Pulse-chase experiments show a shift of silver grains from the nucleolar fibrillar RNP component to the nucleolar granular component first and then to the cytoplasm. Labeling of nucleolar RNA via specific methylation permits the study of intranucleolar processing of pre-rRNA and confirms the sequence of labeling of the two nucleolar RNP components observed with radioactive uridine

S1 pocket fingerprints of human and bacterial methionine aminopeptidases determined using fluorogenic libraries of substrates and phosphorus based inhibitors

Czech Academy of Sciences Publication Activity Database

Poreba, M.; Gajda, A.; Pícha, Jan; Jiráček, Jiří; Marschner, A.; Klein, Ch. D.; Salvesen, G. S.; Drag, M.

2012-01-01

Roč. 94, č. 3 (2012), s. 704-710 ISSN 0300-9084 R&D Projects: GA MŠk(CZ) LC06077 Institutional research plan: CEZ:AV0Z40550506 Keywords : methionine aminopeptidase * substrate library * protease * enzyme * inhibitor * substrate specificity Subject RIV: CC - Organic Chemistry Impact factor: 3.142, year: 2012

Crystal structure of MboIIA methyltransferase

OpenAIRE

Osipiuk, Jerzy; Walsh, Martin A.; Joachimiak, Andrzej

2003-01-01

DNA methyltransferases (MTases) are sequence-specific enzymes which transfer a methyl group from S-adenosyl-l-methionine (AdoMet) to the amino group of either cytosine or adenine within a recognized DNA sequence. Methylation of a base in a specific DNA sequence protects DNA from nucleolytic cleavage by restriction enzymes recognizing the same DNA sequence. We have determined at 1.74 Å resolution the crystal structure of a β-class DNA MTase MboIIA (M·MboIIA) from the bacterium Moraxella bovis,...

Curiosity's Sample Analysis at Mars (SAM) Investigation: Overview of Results from the First 120 Sols on Mars

Science.gov (United States)

Mahaffy, P. R.; Cabane, M.; Webster, C. R.; Archer, P. D.; Atreya, S. K.; Benna, M.; Brinckerhoff, W. B.; Brunner, A. E.; Buch, A.; Coll, P.;

Role of the transsulfuration pathway and of gamma-cystathionase activity in the formation of cysteine and sulfate from methionine in rat hepatocytes

International Nuclear Information System (INIS)

Rao, A.M.; Drake, M.R.; Stipanuk, M.H.

1990-01-01

To assess the extent to which low hepatic gamma-cystathionase levels affect methionine flux to cysteine in hepatocytes, the effect of inhibition of gamma-cystathionase activity with propargylglycine on the metabolism of L-[ 35 S]methionine was determined in studies with freshly isolated rat hepatocytes. gamma-Cystathionase activity was inhibited 25%, 42%, 63% and 76% (maximal inhibition) by treatment with 2.5 mumol/L, 0.01 mmol/L, 0.02 mmol/L and 2 mmol/l propargylglycine, respectively. Inhibition of gamma-cystathionase activity with up to 0.02 mmol/L propargylglycine had no statistically significant effect on [ 35 S]glutathione, [ 35 S]sulfate or [ 35 S]cysteine formation from [ 35 S]methionine. However, treatment of cells with 2 mmol/L propargylglycine markedly inhibited the metabolism of [ 35 S]methionine to [ 35 S]glutathione by 93%, to [ 35 S]sulfate by 88% and to [ 35 S]cysteine by 89%; [ 35 S]cystathionine accumulation in these incubation systems was 60 times control. Hepatic gamma-cystathionase activity in premature infants has been reported to be about 23% of mature levels; this level of gamma-cystathionase activity may limit cysteine synthesis by the methionine transsulfuration pathway. No evidence for cysteine synthesis from serine and sulfide, which can be catalyzed by cystathionine beta-synthase, or for methionine metabolism by an S-adenosylmethionine-independent pathway was obtained

Bacterial variations on the methionine salvage pathway

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Haas Dieter

2004-03-01

Full Text Available Abstract Background The thiomethyl group of S-adenosylmethionine is often recycled as methionine from methylthioadenosine. The corresponding pathway has been unravelled in Bacillus subtilis. However methylthioadenosine is subjected to alternative degradative pathways depending on the organism. Results This work uses genome in silico analysis to propose methionine salvage pathways for Klebsiella pneumoniae, Leptospira interrogans, Thermoanaerobacter tengcongensis and Xylella fastidiosa. Experiments performed with mutants of B. subtilis and Pseudomonas aeruginosa substantiate the hypotheses proposed. The enzymes that catalyze the reactions are recruited from a variety of origins. The first, ubiquitous, enzyme of the pathway, MtnA (methylthioribose-1-phosphate isomerase, belongs to a family of proteins related to eukaryotic intiation factor 2B alpha. mtnB codes for a methylthioribulose-1-phosphate dehydratase. Two reactions follow, that of an enolase and that of a phosphatase. While in B. subtilis this is performed by two distinct polypeptides, in the other organisms analyzed here an enolase-phosphatase yields 1,2-dihydroxy-3-keto-5-methylthiopentene. In the presence of dioxygen an aci-reductone dioxygenase yields the immediate precursor of methionine, ketomethylthiobutyrate. Under some conditions this enzyme produces carbon monoxide in B. subtilis, suggesting a route for a new gaseous mediator in bacteria. Ketomethylthiobutyrate is finally transaminated by an aminotransferase that exists usually as a broad specificity enzyme (often able to transaminate aromatic aminoacid keto-acid precursors or histidinol-phosphate. Conclusion A functional methionine salvage pathway was experimentally demonstrated, for the first time, in P. aeruginosa. Apparently, methionine salvage pathways are frequent in Bacteria (and in Eukarya, with recruitment of different polypeptides to perform the needed reactions (an ancestor of a translation initiation factor and Ru

21 CFR 172.399 - Zinc methionine sulfate.

Science.gov (United States)

2010-04-01

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.399 Zinc methionine sulfate. Zinc methionine...

Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice.

Science.gov (United States)

Neelakantan, Harshini; Vance, Virginia; Wetzel, Michael D; Wang, Hua-Yu Leo; McHardy, Stanton F; Finnerty, Celeste C; Hommel, Jonathan D; Watowich, Stanley J

2018-01-01

There is a critical need for new mechanism-of-action drugs that reduce the burden of obesity and associated chronic metabolic comorbidities. A potentially novel target to treat obesity and type 2 diabetes is nicotinamide-N-methyltransferase (NNMT), a cytosolic enzyme with newly identified roles in cellular metabolism and energy homeostasis. To validate NNMT as an anti-obesity drug target, we investigated the permeability, selectivity, mechanistic, and physiological properties of a series of small molecule NNMT inhibitors. Membrane permeability of NNMT inhibitors was characterized using parallel artificial membrane permeability and Caco-2 cell assays. Selectivity was tested against structurally-related methyltransferases and nicotinamide adenine dinucleotide (NAD + ) salvage pathway enzymes. Effects of NNMT inhibitors on lipogenesis and intracellular levels of metabolites, including NNMT reaction product 1-methylnicotianamide (1-MNA) were evaluated in cultured adipocytes. Effects of a potent NNMT inhibitor on obesity measures and plasma lipid were assessed in diet-induced obese mice fed a high-fat diet. Methylquinolinium scaffolds with primary amine substitutions displayed high permeability from passive and active transport across membranes. Importantly, methylquinolinium analogues displayed high selectivity, not inhibiting related SAM-dependent methyltransferases or enzymes in the NAD + salvage pathway. NNMT inhibitors reduced intracellular 1-MNA, increased intracellular NAD + and S-(5'-adenosyl)-l-methionine (SAM), and suppressed lipogenesis in adipocytes. Treatment of diet-induced obese mice systemically with a potent NNMT inhibitor significantly reduced body weight and white adipose mass, decreased adipocyte size, and lowered plasma total cholesterol levels. Notably, administration of NNMT inhibitors did not impact total food intake nor produce any observable adverse effects. These results support development of small molecule NNMT inhibitors as therapeutics to

Benchmark Simulation of Natural Circulation Cooling System with Salt Working Fluid Using SAM

Energy Technology Data Exchange (ETDEWEB)

Ahmed, K. K.; Scarlat, R. O.; Hu, R.

2017-09-03

Liquid salt-cooled reactors, such as the Fluoride Salt-Cooled High-Temperature Reactor (FHR), offer passive decay heat removal through natural circulation using Direct Reactor Auxiliary Cooling System (DRACS) loops. The behavior of such systems should be well-understood through performance analysis. The advanced system thermal-hydraulics tool System Analysis Module (SAM) from Argonne National Laboratory has been selected for this purpose. The work presented here is part of a larger study in which SAM modeling capabilities are being enhanced for the system analyses of FHR or Molten Salt Reactors (MSR). Liquid salt thermophysical properties have been implemented in SAM, as well as properties of Dowtherm A, which is used as a simulant fluid for scaled experiments, for future code validation studies. Additional physics modules to represent phenomena specific to salt-cooled reactors, such as freezing of coolant, are being implemented in SAM. This study presents a useful first benchmark for the applicability of SAM to liquid salt-cooled reactors: it provides steady-state and transient comparisons for a salt reactor system. A RELAP5-3D model of the Mark-1 Pebble-Bed FHR (Mk1 PB-FHR), and in particular its DRACS loop for emergency heat removal, provides steady state and transient results for flow rates and temperatures in the system that are used here for code-to-code comparison with SAM. The transient studied is a loss of forced circulation with SCRAM event. To the knowledge of the authors, this is the first application of SAM to FHR or any other molten salt reactors. While building these models in SAM, any gaps in the code’s capability to simulate such systems are identified and addressed immediately, or listed as future improvements to the code.

Activities of methionine-γ-lyase in the acidophilic archaeon “Ferroplasma acidarmanus” strain fer1

Directory of Open Access Journals (Sweden)

Khan MA

2013-04-01

Full Text Available M A Khan,1 Madeline M López-Muñoz,2 Charles W Kaspar,3 Kai F Hung1 1Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA; 2Department of Biology, Universidad de Puerto Rico, Mayaguez, Puerto Rico; 3Bacteriology Department, University of Wisconsin, Madison, WI, USA Abstract: Biogeochemical processes on exposed pyrite ores result in extremely high levels of sulfuric acid at these locations. Acidophiles that thrive in these conditions must overcome significant challenges, including an environment with proton concentrations at pH 3 or below. The role of sulfur metabolism in the archaeon “Ferroplasma acidarmanus” strain fer1's ability to thrive in this environment was investigated due to its growth-dependent production of methanethiol, a volatile organic sulfur compound. Two putative sequences for methionine-γ-lyase (EC 4.4.1.11, an enzyme known to carry out α, γ-elimination on L-methionine to produce methanethiol, were identified in fer1. Bioinformatic analyses identified a conserved pyridoxal-5'-phosphate (PLP binding domain and a partially conserved catalytic domain in both putative sequences. Detection of PLP-dependent and L-methionine-dependent production of α-keto compounds and thiol groups in fer1 confirmed the presence of methionine-γ-lyase activity. Further, fer1 lysate was capable of processing related substrates, including D-methionine, L-cysteine, L-cystathionine, and L/D-homocysteine. When the two putative fer1 methionine-γ-lyase gene-coded proteins were expressed in Escherichia coli cells, one sequence demonstrated an ability to carry out α, γ-elimination activity, while the other exhibited γ-replacement activity. These fer1 methionine-γ-lyases also exhibited optimum pH, substrate specificity, and catalytic preferences that are different from methionine-γ-lyases from other organisms. These differences are discussed in the context of molecular phylogeny constructed using a maximum

Methionine as a Precursor of Ethylene—Commentary

Science.gov (United States)

Lieberman et al. showed in a 1966 publication of Plant Physiology that methionine is a precursor of ethylene. It was the first paper that showed ethylene carbons are derived from carbons 3 and 4 of methionine. This paper catalyzed remarkable interest among plant biologists to elucidate the biosynth...

Isozyme-specific enzyme inhibitors. 14. 5'(R)-C-[(L-homocystein-S-yl)methyl]adenosine 5'-(beta,gamma-imidotriphosphate), a potent inhibitor of rat methionine adenosyltransferases.

Science.gov (United States)

Kappler, F; Vrudhula, V M; Hampton, A

1987-09-01

The title compound is a covalent adduct of L-methionine (Met) and beta,gamma-imido-ATP. In its synthesis the N-Boc derivative of 5'(R)-C-(aminomethyl)-N6-benzoyl-5'-O-tosyl-2',3'-O- isopropylidenadenosine was converted by the successive actions of CF3CO2H and HNO2 into the corresponding 5'(R)-C-hydroxymethyl derivative. Treatment of this with disodium L-homocysteinate led to attack of sulfur at C6', apparently via a 5',6'-epoxide, and to total stereoselective inversion at C5' to furnish, after debenzoylation, 5'(R)-C-(L-homocystein-S-ylmethyl)-2',3'-O-isopropylidene ade nosine. The 5' configuration was established by conversion of this into the known 5'(S)-C-methyl-2',3'-O-isopropylidene adenosine with Raney nickel. The alpha-amino acid residue was protected as an N-Boc methyl ester, after which the 5'-hydroxyl was phosphorylated with benzyl phosphate and dicyclohexylcarbodiimide. The phosphoanhydride bond with inorganic imidodiphosphate was then created by established methods. Finally, blocking groups were removed under conditions that gave the desired adduct with no racemization of its L-methionine residue. It was a potent inhibitor [KM(ATP)/Ki = 1080; KM(Met)/Ki = 7.7] of the M-2 (normal tissue) form of rat methionine adenosyltransferase and of the M-T (hepatoma tissue) form [KM(ATP)/Ki = 670; KM(Met)/Ki = 22]. Inhibitions were competitive with respect to ATP or to L-methionine, indicating a dual substrate site mode of binding to the enzyme forms.

Effects of Methionine Containing Paracetamol Formulation on ...

African Journals Online (AJOL)

Effects of Methionine Containing Paracetamol Formulation on Serum Vitamins and Trace Elements in Male Rats. AA Iyanda, JI Anetor, DP Oparinde, FAA Adeniyi. Abstract. Methionine is an effective antidote in the treatment of paracetamol-induced toxicity but at large doses it has been reported to induce or aggravate a ...

The nuclear protein Sam68 is cleaved by the FMDV 3C protease redistributing Sam68 to the cytoplasm during FMDV infection of host cells

International Nuclear Information System (INIS)

Lawrence, Paul; Schafer, Elizabeth A.; Rieder, Elizabeth

2012-01-01

Picornavirus infection can lead to disruption of nuclear pore traffic, shut-off of cell translation machinery, and cleavage of proteins involved in cellular signal transduction and the innate response to infection. Here, we demonstrated that the FMDV 3C pro induced the cleavage of nuclear RNA-binding protein Sam68 C-terminus containing the nuclear localization sequence (NLS). Consequently, it stimulated the redistribution of Sam68 to the cytoplasm. The siRNA knockdown of Sam68 resulted in a 1000-fold reduction in viral titers, which prompted us to study the effect of Sam68 on FMDV post-entry events. Interestingly, Sam68 interacts with the internal ribosomal entry site within the 5′ non-translated region of the FMDV genome, and Sam68 knockdown decreased FMDV IRES-driven activity in vitro suggesting that it could modulate translation of the viral genome. The results uncover a novel role for Sam68 in the context of picornaviruses and the proteolysis of a new cellular target of the FMDV 3C pro .

Analysis of the kinetic mechanism of recombinant human isoprenylcysteine carboxylmethyltransferase (Icmt

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Baron Rudi A

2004-12-01

Full Text Available Abstract Background Isoprenylcysteine carboxyl methyltransferase (Icmt is the third of three enzymes that posttranslationally modify proteins that contain C-terminal CaaX motifs. The processing of CaaX proteins through this so-called prenylation pathway via a route initiated by addition of an isoprenoid lipid is required for both membrane targeting and function of the proteins. The involvement of many CaaX proteins such as Ras GTPases in oncogenesis and other aberrant proliferative disorders has led to the targeting of the enzymes involved in their processing for therapeutic development, necessitating a detailed understanding of the mechanisms of the enzymes. Results In this study, we have investigated the kinetic mechanism of recombinant human Icmt. In the reaction catalyzed by Icmt, S-adenosyl-L-methionine (AdoMet provides the methyl group that is transferred to the second substrate, the C-terminal isoprenylated cysteine residue of a CaaX protein, thereby generating a C-terminal prenylcysteine methyl ester on the protein. To facilitate the kinetic analysis of Icmt, we synthesized a new small molecule substrate of the enzyme, biotin-S-farnesyl-L-cysteine (BFC. Initial kinetic analysis of Icmt suggested a sequential mechanism for the enzyme that was further analyzed using a dead end competitive inhibitor, S-farnesylthioacetic acid (FTA. Inhibition by FTA was competitive with respect to BFC and uncompetitive with respect to AdoMet, indicating an ordered mechanism with SAM binding first. To investigate the order of product dissociation, product inhibition studies were undertaken with S-adenosyl-L-homocysteine (AdoHcy and the N-acetyl-S-farnesyl-L-cysteine methylester (AFCME. This analysis indicated that AdoHcy is a competitive inhibitor with respect to AdoMet, while AFCME shows a noncompetitive inhibition with respect to BFC and a mixed-type inhibition with respect to AdoMet. These studies established that AdoHcy is the final product released, and

Practical synthesis of 14C S-ribosyl-L-homocysteine uniformly labelled on the sugar moiety. An enzymatic route from (U-14C) adenosine

International Nuclear Information System (INIS)

Guillerm, G.; Allart, B.

1992-01-01

[(U- 14 C) S-Ribosyl]-L-homocysteine has been prepared enzymatically from (U- 14 C) adenosine in two steps using S-adenosyl homocysteine hydrolase and bacterial S-adenosyl homocysteine nucleosidase as catalysts. (Author)

Regulation of gene expression by low levels of ultraviolet-B radiation in Pisum sativum: Isolation of novel genes by suppression subtractive hybridisation

International Nuclear Information System (INIS)

Sävenstrand, H.; Brosché, M.; Strid, A.

2002-01-01

Suppression subtractive hybridisation was used to isolate genes differentially regulated by low levels (UV-B BE,300 0.13 W m -2 ) of ultraviolet-B radiation (UV-B; 290–320 nm) in Pisum sativum. Six genes were regulated, two of which were novel. The mRNA levels for these two (PsTSDC and PsUOS1) were increased and depressed by UV-B treatment, respectively. Domains in the PsTSDC translation product was similar to TIR (Toll-Interleukin-1 receptor-similar) domains and a NB-ARC domain (nucleotide-binding domain in APAF-1, R gene products and CED-4). The PsUOS1 translation product was similar to an open reading frame in Arabidopsis. Genes encoding embryo-abundant protein (PsEMB) and S-adenosyl-l-methionine synthase (PsSAMS) were induced by UV-B, whereas the transcript levels for genes encoding sucrose transport protein (PsSUT) or ribulose-5-phosphate 3-epimerase (PsR5P3E) were decreased. These regulation patterns are novel, and the PsEMB and PsR5P3E sequences are reported for the first time. The stress-specificity of regulation of these genes were tested by ozone fumigation (100 ppb O 3 ). Qualitatively, the similarity of expression after both UV-B and ozone exposure suggests that, for these genes, similar stress-response pathways are in action. (author)

Genome sequencing and annotation of Stenotrophomonas sp. SAM8

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Samy Selim

2015-12-01

Full Text Available We report draft genome sequence of Stenotrophomonas sp. strain SAM8, isolated from environmental water. The draft genome size is 3,665,538 bp with a G + C content of 67.2% and contains 6 rRNA sequence (single copies of 5S, 16S & 23S rRNA. The genome sequence can be accessed at DDBJ/EMBL/GenBank under the accession no. LDAV00000000.

The importance of (early) folate status to primary and secondary coronary artery disease prevention

NARCIS (Netherlands)

Muskiet, FAJ

2005-01-01

Folate, methionine, betaine, choline, zinc and Vitamins B-12, B-6 and B-2 are involved in one-carbon metabolism, which includes S-adenosylmethionine (SAM) substrated methylation. Inadequate enzyme activities and imbalances of substrates and cofactors in one-carbon metabolism, together referred to as

Method for the typing of Clostridium difficile based on polyacrylamide gel electrophoresis of [35S]methionine-labeled proteins

International Nuclear Information System (INIS)

Tabaqchali, S.; O'Farrell, S.; Holland, D.; Silman, R.

1986-01-01

A typing method for Clostridium difficile based on the incorporation of [ 35 S]methionine into cellular proteins, their separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their visualization by autoradiography is described. On analysis of the radiolabeled-protein profiles, nine distinct groups were observed (A to E and W to Z). The method, which is simple, reproducible, and readily expandable, has been applied in epidemiological studies to demonstrate cross-infection and hospital acquisition of C. difficile

Reactions of cisplatin with cysteine and methionine at constant pH; a computational study.

Science.gov (United States)

Zimmermann, Tomás; Burda, Jaroslav V

2010-02-07

Interactions of hydrated cisplatin complexes cis-[Pt(NH(3))(2)Cl(H(2)O)](+) and cis-[Pt(NH(3))(2)(OH)(H(2)O)](+) with cysteine and methionine in an aqueous solution at constant pH were explored using computational methods. Thermodynamic parameters of considered reactions were studied in a broad pH range, taking up to 4 protonation states of each molecule into account. Reaction free energies at constant pH were obtained from standard Gibbs free energies using the Legendre transformation. Solvation free energies and pK(a) values were calculated using the PCM model with UAHF cavities, recently adapted by us for transition metal complexes. The root mean square error of pK(a) values on a set of model platinum complexes and amino acids was equal to 0.74. At pH 7, the transformed Gibbs free energies differ by up to 15 kcal mol(-1) from the Gibbs free energies of model reactions with a constant number of protons. As for cysteine, calculations confirmed a strong preference for kappaS monodenate bonding in a broad pH range. The most stable product of the second reaction step, which proceeds from monodentate to chelate complex, is the kappa(2)S,N coordinated chelate. The reaction with methionine is more complex. In the first step all three considered methionine donor atoms (N, S and O) are thermodynamically preferred products depending on the platinum complex and the pH. This is in accordance with the experimental observation of a pH dependent migration between N and S donor atoms in a chemically related system. The most stable chelates of platinum with methionine are kappa(2)S,N and kappa(2)N,O bonded complexes. The comparison of reaction free energies of both amino acids suggests, that the bidentate methionine ligand can be displaced even by the monodentate cysteine ligand under certain conditions.

A common mutation in the 5,10-methylenetetrahydrofolate reductase gene affects genomic DNA methylation through an interaction with folate status

Science.gov (United States)

Friso, Simonetta; Choi, Sang-Woon; Girelli, Domenico; Mason, Joel B.; Dolnikowski, Gregory G.; Bagley, Pamela J.; Olivieri, Oliviero; Jacques, Paul F.; Rosenberg, Irwin H.; Corrocher, Roberto; Selhub, Jacob

2002-01-01

DNA methylation, an essential epigenetic feature of DNA that modulates gene expression and genomic integrity, is catalyzed by methyltransferases that use the universal methyl donor S-adenosyl-l-methionine. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the synthesis of 5-methyltetrahydrofolate (5-methylTHF), the methyl donor for synthesis of methionine from homocysteine and precursor of S-adenosyl-l-methionine. In the present study we sought to determine the effect of folate status on genomic DNA methylation with an emphasis on the interaction with the common C677T mutation in the MTHFR gene. A liquid chromatography/MS method for the analysis of nucleotide bases was used to assess genomic DNA methylation in peripheral blood mononuclear cell DNA from 105 subjects homozygous for this mutation (T/T) and 187 homozygous for the wild-type (C/C) MTHFR genotype. The results show that genomic DNA methylation directly correlates with folate status and inversely with plasma homocysteine (tHcy) levels (P < 0.01). T/T genotypes had a diminished level of DNA methylation compared with those with the C/C wild-type (32.23 vs.62.24 ng 5-methylcytosine/μg DNA, P < 0.0001). When analyzed according to folate status, however, only the T/T subjects with low levels of folate accounted for the diminished DNA methylation (P < 0.0001). Moreover, in T/T subjects DNA methylation status correlated with the methylated proportion of red blood cell folate and was inversely related to the formylated proportion of red blood cell folates (P < 0.03) that is known to be solely represented in those individuals. These results indicate that the MTHFR C677T polymorphism influences DNA methylation status through an interaction with folate status. PMID:11929966

Follicular thyroid cancer avid on C-11 Methionine PET/CT

OpenAIRE

Jochumsen, Mads Ryø; Iversen, Peter; Arveschoug, Anne Kirstine

2018-01-01

Summary A case of follicular thyroid cancer with intense focal Methionine uptake on 11C-Methionine PET/CT is reported here. The use of 11C-Methionine PET in differentiated thyroid cancer is currently being investigated as a surrogate tracer compared to the more widely used 18F-FDG PET. This case illustrates the potential incremental value of this modality, not only in the localizing of parathyroid adenoma, but also indicating that 11C-Methionine PET might have a potential of increasing the pr...

Prediction of Methionine and Homocysteine levels in Zucker diabetic fatty (ZDF) rats as a T2DM animal model after consumption of a Methionine-rich diet

OpenAIRE

Han, Nayoung; Chae, Jung-woo; Jeon, Jihyun; Lee, Jaeyeon; Back, Hyun-moon; Song, Byungjeong; Kwon, Kwang-il; Kim, Sang Kyum; Yun, Hwi-yeol

2018-01-01

Background Although alterations in the methionine metabolism cycle (MMC) have been associated with vascular complications of diabetes, there have not been consistent results about the levels of methionine and homocysteine in type 2 diabetes mellitus (T2DM). The aim of the current study was to predict changes in plasma methionine and homocysteine concentrations after simulated consumption of methionine-rich foods, following the development of a mathematical model for MMC in Zucker Diabetic Fat...

Boron (B) deprivation increases plasma homocysteine and decreases liver S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in rats

Science.gov (United States)

The diverse effects of B deprivation suggest that B affects a biomolecule involved in a variety of biochemical reactions. An experiment was conducted to determine whether dietary B affects the liver concentration of SAM, a frequently used enzyme substrate, especially for methylation reactions that y...

Crystal complexes of a predicted S-adenosylmethionine-dependent methyltransferase reveal a typical AdoMet binding domain and a substrate recognition domain

Energy Technology Data Exchange (ETDEWEB)

Miller, D.J.; Ouellette, N.; Evodokimova, E.; Savchenko, A.; Edwards, A.; Anderson, W.F. (Toronto); (NWU)

2010-03-08

S-adenosyl-L-methionine-dependent methyltransferases (MTs) are abundant, and highly conserved across phylogeny. These enzymes use the cofactor AdoMet to methylate a wide variety of molecular targets, thereby modulating important cellular and metabolic activities. Thermotoga maritima protein 0872 (TM0872) belongs to a large sequence family of predicted MTs, ranging phylogenetically from relatively simple bacteria to humans. The genes for many of the bacterial homologs are located within operons involved in cell wall synthesis and cell division. Despite preliminary biochemical studies in E. coli and B. subtilis, the substrate specificity of this group of more than 150 proteins is unknown. As part of the Midwest Center for Structural Genomics initiative (www.mcsg.anl.gov), we have determined the structure of TM0872 in complexes with AdoMet and with S-adenosyl-L-homocysteine (AdoHcy). As predicted, TM0872 has a typical MT domain, and binds endogenous AdoMet, or co-crystallized AdoHcy, in a manner consistent with other known MT structures. In addition, TM0872 has a second domain that is novel among MTs in both its location in the sequence and its structure. The second domain likely acts in substrate recognition and binding, and there is a potential substrate-binding cleft spanning the two domains. This long and narrow cleft is lined with positively charged residues which are located opposite the S{sup +}-CH{sub 3} bond, suggesting that a negatively charged molecule might be targeted for catalysis. However, AdoMet and AdoHcy are both buried, and access to the methyl group would presumably require structural rearrangement. These TM0872 crystal structures offer the first structural glimpses at this phylogenetically conserved sequence family.

Folate (vitamin B9) and vitamin B12 and their function in the maintenance of nuclear and mitochondrial genome integrity

International Nuclear Information System (INIS)

Fenech, Michael

2012-01-01

Folate plays a critical role in the prevention of uracil incorporation into DNA and hypomethylation of DNA. This activity is compromised when vitamin B12 concentration is low because methionine synthase activity is reduced, lowering the concentration of S-adenosyl methionine (SAM) which in turn may diminish DNA methylation and cause folate to become unavailable for the conversion of dUMP to dTMP. The most plausible explanation for the chromosome-breaking effect of low folate is excessive uracil misincorporation into DNA, a mutagenic lesion that leads to strand breaks in DNA during repair. Both in vitro and in vivo studies with human cells clearly show that folate deficiency causes expression of chromosomal fragile sites, chromosome breaks, excessive uracil in DNA, micronucleus formation, DNA hypomethylation and mitochondrial DNA deletions. In vivo studies show that folate and/or vitamin B12 deficiency and elevated plasma homocysteine (a metabolic indicator of folate deficiency) are significantly correlated with increased micronucleus formation and reduced telomere length respectively. In vitro experiments indicate that genomic instability in human cells is minimised when folic acid concentration in culture medium is greater than 100 nmol/L. Intervention studies in humans show (a) that DNA hypomethylation, chromosome breaks, uracil incorporation and micronucleus formation are minimised when red cell folate concentration is greater than 700 nmol/L and (b) micronucleus formation is minimised when plasma concentration of vitamin B12 is greater than 300 pmol/L and plasma homocysteine is less than 7.5 μmol/L. These concentrations are achievable at intake levels at or above current recommended dietary intakes of folate (i.e. >400 μg/day) and vitamin B12 (i.e. >2 μg/day) depending on an individual's capacity to absorb and metabolise these vitamins which may vary due to genetic and epigenetic differences.

Information System through ANIS at CeSAM

Science.gov (United States)

Moreau, C.; Agneray, F.; Gimenez, S.

2015-09-01

ANIS (AstroNomical Information System) is a web generic tool developed at CeSAM to facilitate and standardize the implementation of astronomical data of various kinds through private and/or public dedicated Information Systems. The architecture of ANIS is composed of a database server which contains the project data, a web user interface template which provides high level services (search, extract and display imaging and spectroscopic data using a combination of criteria, an object list, a sql query module or a cone search interfaces), a framework composed of several packages, and a metadata database managed by a web administration entity. The process to implement a new ANIS instance at CeSAM is easy and fast : the scientific project has to submit data or a data secure access, the CeSAM team installs the new instance (web interface template and the metadata database), and the project administrator can configure the instance with the web ANIS-administration entity. Currently, the CeSAM offers through ANIS a web access to VO compliant Information Systems for different projects (HeDaM, HST-COSMOS, CFHTLS-ZPhots, ExoDAT,...).

Molten Salt Power Tower Cost Model for the System Advisor Model (SAM)

Energy Technology Data Exchange (ETDEWEB)

Turchi, C. S.; Heath, G. A.

2013-02-01

This report describes a component-based cost model developed for molten-salt power tower solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), using data from several prior studies, including a contracted analysis from WorleyParsons Group, which is included herein as an Appendix. The WorleyParsons' analysis also estimated material composition and mass for the plant to facilitate a life cycle analysis of the molten salt power tower technology. Details of the life cycle assessment have been published elsewhere. The cost model provides a reference plant that interfaces with NREL's System Advisor Model or SAM. The reference plant assumes a nominal 100-MWe (net) power tower running with a nitrate salt heat transfer fluid (HTF). Thermal energy storage is provided by direct storage of the HTF in a two-tank system. The design assumes dry-cooling. The model includes a spreadsheet that interfaces with SAM via the Excel Exchange option in SAM. The spreadsheet allows users to estimate the costs of different-size plants and to take into account changes in commodity prices. This report and the accompanying Excel spreadsheet can be downloaded at https://sam.nrel.gov/cost.

Jo Ann Baumgartner and Sam Earnshaw: Organizers and Farmers

OpenAIRE

Rabkin, Sarah

2010-01-01

Jo Ann Baumgartner directs the Wild Farm Alliance, based in Watsonville, California. WFA’s mission, as described on the organization’s website, is “to promote agriculture that helps to protect and restore wild Nature.” Through research, publications, presentations, events, policy work, and consulting, the organization works to “connect food systems with ecosystems.” Sam Earnshaw is Central Coast regional coordinator of the Community Alliance with Family Farmers. Working with CAFF’s f...

Extra-virgin olive oil contains a metabolo-epigenetic inhibitor of cancer stem cells

Science.gov (United States)

Corominas-Faja, Bruna; Cuyàs, Elisabet; Lozano-Sánchez, Jesús; Cufí, Sílvia; Verdura, Sara; Fernández-Arroyo, Salvador; Borrás-Linares, Isabel; Martin-Castillo, Begoña; Martin, Ángel G; Lupu, Ruth; Nonell-Canals, Alfons; Micol, Vicente; Joven, Jorge; Segura-Carretero, Antonio; Menendez, Javier A

2018-01-01

Abstract Targeting tumor-initiating, drug-resistant populations of cancer stem cells (CSC) with phytochemicals is a novel paradigm for cancer prevention and treatment. We herein employed a phenotypic drug discovery approach coupled to mechanism-of-action profiling and target deconvolution to identify phenolic components of extra virgin olive oil (EVOO) capable of suppressing the functional traits of CSC in breast cancer (BC). In vitro screening revealed that the secoiridoid decarboxymethyl oleuropein aglycone (DOA) could selectively target subpopulations of epithelial-like, aldehyde dehydrogenase (ALDH)-positive and mesenchymal-like, CD44+CD24−/low CSC. DOA could potently block the formation of multicellular tumorspheres generated from single-founder stem-like cells in a panel of genetically diverse BC models. Pretreatment of BC populations with noncytotoxic doses of DOA dramatically reduced subsequent tumor-forming capacity in vivo. Mice orthotopically injected with CSC-enriched BC-cell populations pretreated with DOA remained tumor-free for several months. Phenotype microarray-based screening pointed to a synergistic interaction of DOA with the mTOR inhibitor rapamycin and the DNA methyltransferase (DNMT) inhibitor 5-azacytidine. In silico computational studies indicated that DOA binds and inhibits the ATP-binding kinase domain site of mTOR and the S-adenosyl-l-methionine (SAM) cofactor-binding pocket of DNMTs. FRET-based Z-LYTE™ and AlphaScreen-based in vitro assays confirmed the ability of DOA to function as an ATP-competitive mTOR inhibitor and to block the SAM-dependent methylation activity of DNMTs. Our systematic in vitro, in vivo and in silico approaches establish the phenol-conjugated oleoside DOA as a dual mTOR/DNMT inhibitor naturally occurring in EVOO that functionally suppresses CSC-like states responsible for maintaining tumor-initiating cell properties within BC populations. PMID:29452350

Stress-induced gene expression and behavior are controlled by DNA methylation and methyl donor availability in the dentate gyrus

Science.gov (United States)

Saunderson, Emily A.; Spiers, Helen; Gutierrez-Mecinas, Maria; Trollope, Alexandra F.; Shaikh, Abeera; Mill, Jonathan; Reul, Johannes M. H. M.

2016-01-01

Stressful events evoke long-term changes in behavioral responses; however, the underlying mechanisms in the brain are not well understood. Previous work has shown that epigenetic changes and immediate-early gene (IEG) induction in stress-activated dentate gyrus (DG) granule neurons play a crucial role in these behavioral responses. Here, we show that an acute stressful challenge [i.e., forced swimming (FS)] results in DNA demethylation at specific CpG (5′-cytosine–phosphate–guanine-3′) sites close to the c-Fos (FBJ murine osteosarcoma viral oncogene homolog) transcriptional start site and within the gene promoter region of Egr-1 (early growth response protein 1) specifically in the DG. Administration of the (endogenous) methyl donor S-adenosyl methionine (SAM) did not affect CpG methylation and IEG gene expression at baseline. However, administration of SAM before the FS challenge resulted in an enhanced CpG methylation at the IEG loci and suppression of IEG induction specifically in the DG and an impaired behavioral immobility response 24 h later. The stressor also specifically increased the expression of the de novo DNA methyltransferase Dnmt3a [DNA (cytosine-5-)-methyltransferase 3 alpha] in this hippocampus region. Moreover, stress resulted in an increased association of Dnmt3a enzyme with the affected CpG loci within the IEG genes. No effects of SAM were observed on stress-evoked histone modifications, including H3S10p-K14ac (histone H3, phosphorylated serine 10 and acetylated lysine-14), H3K4me3 (histone H3, trimethylated lysine-4), H3K9me3 (histone H3, trimethylated lysine-9), and H3K27me3 (histone H3, trimethylated lysine-27). We conclude that the DNA methylation status of IEGs plays a crucial role in FS-induced IEG induction in DG granule neurons and associated behavioral responses. In addition, the concentration of available methyl donor, possibly in conjunction with Dnmt3a, is critical for the responsiveness of dentate neurons to environmental

78 FR 47695 - Sam Rayburn Dam Power Rate

Science.gov (United States)

2013-08-06

... DEPARTMENT OF ENERGY Southwestern Power Administration Sam Rayburn Dam Power Rate AGENCY: Southwestern Power Administration, DOE. ACTION: Notice of public review and comment. SUMMARY: The current Sam..., Southwestern Power Administration (Southwestern), has prepared Current and Revised 2013 Power Repayment Studies...

The methionine salvage pathway in Bacillus subtilis

Directory of Open Access Journals (Sweden)

Danchin Antoine

2002-04-01

Full Text Available Abstract Background Polyamine synthesis produces methylthioadenosine, which has to be disposed of. The cell recycles it into methionine through methylthioribose (MTR. Very little was known about MTR recycling for methionine salvage in Bacillus subtilis. Results Using in silico genome analysis and transposon mutagenesis in B. subtilis we have experimentally uncovered the major steps of the dioxygen-dependent methionine salvage pathway, which, although similar to that found in Klebsiella pneumoniae, recruited for its implementation some entirely different proteins. The promoters of the genes have been identified by primer extension, and gene expression was analyzed by Northern blotting and lacZ reporter gene expression. Among the most remarkable discoveries in this pathway is the role of an analog of ribulose diphosphate carboxylase (Rubisco, the plant enzyme used in the Calvin cycle which recovers carbon dioxide from the atmosphere as a major step in MTR recycling. Conclusions A complete methionine salvage pathway exists in B. subtilis. This pathway is chemically similar to that in K. pneumoniae, but recruited different proteins to this purpose. In particular, a paralogue or Rubisco, MtnW, is used at one of the steps in the pathway. A major observation is that in the absence of MtnW, MTR becomes extremely toxic to the cell, opening an unexpected target for new antimicrobial drugs. In addition to methionine salvage, this pathway protects B. subtilis against dioxygen produced by its natural biotope, the surface of leaves (phylloplane.

Acute Administration of Methionine Affects Performance of Swiss ...

African Journals Online (AJOL)

Acetylcholinesterase activities in all groups were not statistically significant. It can be concluded that acute methionine administration has some benefits in memory enhancement. However, a short course folate supplementation impairslearning and working memory especially when combined with methionine which may be ...

EFFICACY OF REMAXOL AND ADEMETHIONINE IN EXPERIMENTAL LIVER DAMAGE CAUSED BY A COMBINATION OF RESERVE-SERIES ANTITUBERCULOSIS DRUGS AND ALCOHOL

Directory of Open Access Journals (Sweden)

D. S. Sukhanov

2014-01-01

Full Text Available The hepatic and endothelial protective effects of remaxol and S-adenosyl-L-methionine were studied on 24 male rats with liver damage caused by reserve-series antituberculosis drugs in combination with alcohol. The test agents were found to have a unilateral hepatoprotective effect in decreasing the blood levels of triglycerides, bilirubin, and alkaline phosphatase with a concurrent significant reduction in the manifestations of hyaline-drop and hydropic dystrophy of hepatocytes. Remaxol and ademethionine have the same endothelial protective activity manifested as normalization of an endothelium-dependent vasodilation response and endothelial dysfunction coefficient.

Polyamines and polyamine biosynthesis in cells exposed to hyperthermia

Energy Technology Data Exchange (ETDEWEB)

Gerner, E.W.; Stickney, D.G.; Herman, T.S.; Fuller, D.J.

1983-02-01

The issue of how polyamines act to sensitize cultured cells to the lethal effects of hyperthermia was investigated using Chinese hamster cells which were induced to express thermotolerance. Intracellular levels of these naturally occurring polycations were manipulated in certain situations by treating whole cells with methylglyoxal bis-(guanylhydrazone), an inhibitor of the S-adenosyl-L-methionine decarboxylases. Exogenous spermine as low as 100 ..mu..M in the culture media dramatically sensitized cells expressing thermotolerance to the lethal effects of subsequent 42/sup 0/C exposures. When thermotolerance was differentially induced in cultures exposed to 42.4/sup 0/C by varying the rate of heating from 37 to 42.4/sup 0/C, the most resistant cells and the highest levels of intracellular spermidine and spermine. This finding was explainable in part by the observation that the putrescine-dependent S-adenosyl-L-methionine decarboxylase activity was minimally affected in cells expressng the greatest degree of thermotolerance. When this enzyme activity was inhibited by drug, lowered intracellular polyamine levels did not correspond with subsequent survival responses to heat. Interestingly, cultures treated with methylglyoxal bis-(guanylhydrazone) 24 hr previous to heat exposure showed a reduced capacity to express rate of heating-induced thermotolerance. Together, these results demonstrate that the polyamines, especially spermidine and spermine, enhance hyperthermia-induced cell killing by some mechanism involving the plasma membrane. Further, our data suggest that methylglyoxal bis-(guanylhydrazone) can act to affect thermal responses by a mechanism(s) other than modification of intracellular polyamine levels.

Follicular thyroid cancer avid on C-11 Methionine PET/CT

Directory of Open Access Journals (Sweden)

Mads Ryø Jochumsen

2018-01-01

Full Text Available A case of follicular thyroid cancer with intense focal Methionine uptake on 11C-Methionine PET/CT is reported here. The use of 11C-Methionine PET in differentiated thyroid cancer is currently being investigated as a surrogate tracer compared to the more widely used 18F-FDG PET. This case illustrates the potential incremental value of this modality, not only in the localizing of parathyroid adenoma, but also indicating that 11C-Methionine PET might have a potential of increasing the pretest likelihood of thyroid malignancy in a cold nodule with highly increased Sestamibi uptake.

Comparative efficacy of herbal and synthetic methionine on ...

African Journals Online (AJOL)

HM) compared to synthetic methionine (SM) in the diets of domestic laying hens. The herbal methionine (Meth-o-Tas®) was supplied by Intas Pharmaceutical Limited, India. The HM and SM were added to a standard diet at 0.5 and 1.0 kg per ...

Influence of dietary methionine on the metabolism of selenomethionine in rats

International Nuclear Information System (INIS)

Butler, J.A.; Beilstein, M.A.; Whanger, P.D.

1989-01-01

To determine the influence of methionine on selenomethionine (SeMet) metabolism, weanling male rats were fed for 8 wk a basal diet marginally deficient in sulfur amino acids, containing 2.0 micrograms selenium (Se)/g as DL-SeMet and supplemented with 0, 0.3, 0.6 or 1.2% DL-methionine. Increased dietary methionine caused decreased selenium deposition in all tissues examined but increased glutathione peroxidase activity in testes, liver and lungs. A positive correlation was found between dietary methionine and the calculated percentage of selenium associated with GSHPx. In a second experiment, 75 SeMet was injected into weanling male rats which had been fed the basal diet containing 2.0 micrograms selenium as DL-SeMet with or without the addition of 1.0% methionine. The selenoamino acid content of tissues and the distribution of 75 Se in erythrocyte proteins were determined. In comparison to the rats fed the basal diet without added methionine, significantly more 75 Se-selenocysteine was found in liver and muscle, more 75 Se was found in erythrocyte GSHPx and less 75 Se was found in erythrocyte hemoglobin of rats fed 1.0% methionine. These data suggest that methionine diverts SeMet from incorporation into general proteins and enhances its conversion to selenocysteine for specific selenium-requiring proteins, such as GSHPx

Smoking-Attributable Mortality, Morbidity, and Economic Costs (SAMMEC) - Smoking-Attributable Mortality (SAM)

Data.gov (United States)

U.S. Department of Health & Human Services — 2005-2009. SAMMEC - Smoking-Attributable Mortality, Morbidity, and Economic Costs. Smoking-attributable mortality (SAM) is the number of deaths caused by cigarette...

Technical Manual for the SAM Biomass Power Generation Model

Energy Technology Data Exchange (ETDEWEB)

Jorgenson, J.; Gilman, P.; Dobos, A.

2011-09-01

This technical manual provides context for the implementation of the biomass electric power generation performance model in the National Renewable Energy Laboratory's (NREL's) System Advisor Model (SAM). Additionally, the report details the engineering and scientific principles behind the underlying calculations in the model. The framework established in this manual is designed to give users a complete understanding of behind-the-scenes calculations and the results generated.

Method for the typing of Clostridium difficile based on polyacrylamide gel electrophoresis of (/sup 35/S)methionine-labeled proteins

Energy Technology Data Exchange (ETDEWEB)

Tabaqchali, S.; O' Farrell, S.; Holland, D.; Silman, R.

1986-01-01

A typing method for Clostridium difficile based on the incorporation of (/sup 35/S)methionine into cellular proteins, their separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their visualization by autoradiography is described. On analysis of the radiolabeled-protein profiles, nine distinct groups were observed (A to E and W to Z). The method, which is simple, reproducible, and readily expandable, has been applied in epidemiological studies to demonstrate cross-infection and hospital acquisition of C. difficile.

Congressmember Sam Farr: Five Decades of Public Service

OpenAIRE

Reti, Irene H.; Farr, Sam

2017-01-01

Congressmember Sam Farr (born July 4, 1941) represented California’s Central Coast in the United States House of Representatives for twenty-three years until his retirement from office in 2016.  Farr also served six years as a member of the Monterey County Board of Supervisors and twelve years in the California State Assembly. This oral history, a transcript of twenty-five hours of interviews conducted by Irene Reti, director of the UCSC Library’s Regional History Project, during the period i...

Raman mapping and in situ SERS spectroelectrochemical studies of 6-mercaptopurine SAMs on the gold electrode.

Science.gov (United States)

Yang, Haifeng; Liu, Yanli; Liu, Zhimin; Yang, Yu; Jiang, Jianhui; Zhang, Zongrang; Shen, Guoli; Yu, Ruqin

2005-02-24

The self-assembled monolayers (SAMs) of 6-mercaptopurine (6MP) were formed at the roughened polycrystalline gold surfaces in acid and alkaline media. The time-dependent Raman mapping spectral analysis in conjunction with the quantum calculations for the vibrational modes using ab initio BLYP/6-31G method suggested that both of the resulted 6MP SAMs adopted the same adsorption mode through the S atom of pyrimidine moiety and the N7 atom of the imidazole moiety anchoring the gold surface in a vertical way. The in situ surface-enhanced Raman scattering spectroelectrochemical experiment was conducted to examine the stability of the SAMs at various bias potentials. It was found that the detaching process of the 6MP SAMs from the surface involved one electron reduction as the voltage was applied at ca. 0.7 V vs a standard calomel electrode.

Genetic basis of metabolome variation in yeast.

Directory of Open Access Journals (Sweden)

Jeffrey S Breunig

2014-03-01

Full Text Available Metabolism, the conversion of nutrients into usable energy and biochemical building blocks, is an essential feature of all cells. The genetic factors responsible for inter-individual metabolic variability remain poorly understood. To investigate genetic causes of metabolome variation, we measured the concentrations of 74 metabolites across ~ 100 segregants from a Saccharomyces cerevisiae cross by liquid chromatography-tandem mass spectrometry. We found 52 quantitative trait loci for 34 metabolites. These included linkages due to overt changes in metabolic genes, e.g., linking pyrimidine intermediates to the deletion of ura3. They also included linkages not directly related to metabolic enzymes, such as those for five central carbon metabolites to ira2, a Ras/PKA pathway regulator, and for the metabolites, S-adenosyl-methionine and S-adenosyl-homocysteine to slt2, a MAP kinase involved in cell wall integrity. The variant of ira2 that elevates metabolite levels also increases glucose uptake and ethanol secretion. These results highlight specific examples of genetic variability, including in genes without prior known metabolic regulatory function, that impact yeast metabolism.

Isolation of L-methionine-enriched mutant of a methylotrophic yeast, Candida boidinii No.2201

International Nuclear Information System (INIS)

Tani, Y.; Lim, W.J.; Yang, H.C.

1988-01-01

Six strains of methylotrophic yeast were examined for production of L-methionine-enriched cells. Candida boidinii (kloeckera sp.) No. 2201,which accumulated 0.54 mg/g-dry cell weight (DCW) of free L-methionine (pool methionine), was selected as the parental strain for breeding L-methionine-rich mutants. Ethionine-resistant mutants were derived from the strain by UV irradiation. A mutant strain, E500-78,which was resistant to 500 μg/ml of DL-ethionine, accumulated 6.02 mg/g-DCW of pool methionine. The culture conditions for mutant strain E500-78 to increase pool methionine accumulation were optimized. As a result, the mutant strain accumulated 8.80 mg/g-DCW of pool methionine and contained 16.02 mg/g-DCW total methionine

Determination of the Structure and Catalytic Mechanism of Sorghum bicolor Caffeic Acid O-Methyltransferase and the Structural Impact of Three brown midrib12 Mutations1[W

Science.gov (United States)

Green, Abigail R.; Lewis, Kevin M.; Barr, John T.; Jones, Jeffrey P.; Lu, Fachuang; Ralph, John; Vermerris, Wilfred; Sattler, Scott E.; Kang, ChulHee

2014-01-01

Using S-adenosyl-methionine as the methyl donor, caffeic acid O-methyltransferase from sorghum (Sorghum bicolor; SbCOMT) methylates the 5-hydroxyl group of its preferred substrate, 5-hydroxyconiferaldehyde. In order to determine the mechanism of SbCOMT and understand the observed reduction in the lignin syringyl-to-guaiacyl ratio of three brown midrib12 mutants that carry COMT gene missense mutations, we determined the apo-form and S-adenosyl-methionine binary complex SbCOMT crystal structures and established the ternary complex structure with 5-hydroxyconiferaldehyde by molecular modeling. These structures revealed many features shared with monocot ryegrass (Lolium perenne) and dicot alfalfa (Medicago sativa) COMTs. SbCOMT steady-state kinetic and calorimetric data suggest a random bi-bi mechanism. Based on our structural, kinetic, and thermodynamic results, we propose that the observed reactivity hierarchy among 4,5-dihydroxy-3-methoxycinnamyl (and 3,4-dihydroxycinnamyl) aldehyde, alcohol, and acid substrates arises from the ability of the aldehyde to stabilize the anionic intermediate that results from deprotonation of the 5-hydroxyl group by histidine-267. Additionally, despite the presence of other phenylpropanoid substrates in vivo, sinapaldehyde is the preferential product, as demonstrated by its low Km for 5-hydroxyconiferaldehyde. Unlike its acid and alcohol substrates, the aldehydes exhibit product inhibition, and we propose that this is due to nonproductive binding of the S-cis-form of the aldehydes inhibiting productive binding of the S-trans-form. The S-cis-aldehydes most likely act only as inhibitors, because the high rotational energy barrier around the 2-propenyl bond prevents S-trans-conversion, unlike alcohol substrates, whose low 2-propenyl bond rotational energy barrier enables rapid S-cis/S-trans-interconversion. PMID:24948836

Determination of the Structure and Catalytic Mechanism of Sorghum bicolor Caffeic Acid O-Methyltransferase and the Structural Impact of Three brown midrib12 Mutations.

Science.gov (United States)

Green, Abigail R; Lewis, Kevin M; Barr, John T; Jones, Jeffrey P; Lu, Fachuang; Ralph, John; Vermerris, Wilfred; Sattler, Scott E; Kang, ChulHee

2014-08-01

Using S-adenosyl-methionine as the methyl donor, caffeic acid O-methyltransferase from sorghum (Sorghum bicolor; SbCOMT) methylates the 5-hydroxyl group of its preferred substrate, 5-hydroxyconiferaldehyde. In order to determine the mechanism of SbCOMT and understand the observed reduction in the lignin syringyl-to-guaiacyl ratio of three brown midrib12 mutants that carry COMT gene missense mutations, we determined the apo-form and S-adenosyl-methionine binary complex SbCOMT crystal structures and established the ternary complex structure with 5-hydroxyconiferaldehyde by molecular modeling. These structures revealed many features shared with monocot ryegrass (Lolium perenne) and dicot alfalfa (Medicago sativa) COMTs. SbCOMT steady-state kinetic and calorimetric data suggest a random bi-bi mechanism. Based on our structural, kinetic, and thermodynamic results, we propose that the observed reactivity hierarchy among 4,5-dihydroxy-3-methoxycinnamyl (and 3,4-dihydroxycinnamyl) aldehyde, alcohol, and acid substrates arises from the ability of the aldehyde to stabilize the anionic intermediate that results from deprotonation of the 5-hydroxyl group by histidine-267. Additionally, despite the presence of other phenylpropanoid substrates in vivo, sinapaldehyde is the preferential product, as demonstrated by its low K m for 5-hydroxyconiferaldehyde. Unlike its acid and alcohol substrates, the aldehydes exhibit product inhibition, and we propose that this is due to nonproductive binding of the S-cis-form of the aldehydes inhibiting productive binding of the S-trans-form. The S-cis-aldehydes most likely act only as inhibitors, because the high rotational energy barrier around the 2-propenyl bond prevents S-trans-conversion, unlike alcohol substrates, whose low 2-propenyl bond rotational energy barrier enables rapid S-cis/S-trans-interconversion. © 2014 American Society of Plant Biologists. All Rights Reserved.

21 CFR 582.5477 - Methionine hydroxy analog and its calcium salts.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Methionine hydroxy analog and its calcium salts... Nutrients and/or Dietary Supplements 1 § 582.5477 Methionine hydroxy analog and its calcium salts. (a) Product. Methionine hydroxy analog and its calcium salts. (b) [Reserved] (c) Limitations, restrictions, or...

Differential identification of Candida species and other yeasts by analysis of [35S]methionine-labeled polypeptide profiles

International Nuclear Information System (INIS)

Shen, H.D.; Choo, K.B.; Tsai, W.C.; Jen, T.M.; Yeh, J.Y.; Han, S.H.

1988-01-01

This paper describes a scheme for differential identification of Candida species and other yeasts based on autoradiographic analysis of protein profiles of [ 35 S]methionine-labeled cellular proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Using ATCC strains as references, protein profile analysis showed that different Candida and other yeast species produced distinctively different patterns. Good agreement in results obtained with this approach and with other conventional systems was observed. Being accurate and reproducible, this approach provides a basis for the development of an alternative method for the identification of yeasts isolated from clinical specimens

Parabolic Trough Collector Cost Update for the System Advisor Model (SAM)

Energy Technology Data Exchange (ETDEWEB)

Kurup, Parthiv [National Renewable Energy Lab. (NREL), Golden, CO (United States); Turchi, Craig S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-11-01

This report updates the baseline cost for parabolic trough solar fields in the United States within NREL's System Advisor Model (SAM). SAM, available at no cost at https://sam.nrel.gov/, is a performance and financial model designed to facilitate decision making for people involved in the renewable energy industry. SAM is the primary tool used by NREL and the U.S. Department of Energy (DOE) for estimating the performance and cost of concentrating solar power (CSP) technologies and projects. The study performed a bottom-up build and cost estimate for two state-of-the-art parabolic trough designs -- the SkyTrough and the Ultimate Trough. The SkyTrough analysis estimated the potential installed cost for a solar field of 1500 SCAs as $170/m² +/- $6/m². The investigation found that SkyTrough installed costs were sensitive to factors such as raw aluminum alloy cost and production volume. For example, in the case of the SkyTrough, the installed cost would rise to nearly $210/m² if the aluminum alloy cost was $1.70/lb instead of $1.03/lb. Accordingly, one must be aware of fluctuations in the relevant commodities markets to track system cost over time. The estimated installed cost for the Ultimate Trough was only slightly higher at $178/m², which includes an assembly facility of $11.6 million amortized over the required production volume. Considering the size and overall cost of a 700 SCA Ultimate Trough solar field, two parallel production lines in a fully covered assembly facility, each with the specific torque box, module and mirror jigs, would be justified for a full CSP plant.

Stabilization of sulfide cations: mechanisms relevant to oxidation of peptides and proteins containing methionine

International Nuclear Information System (INIS)

Bobrowski, K.; Hug, G.L.; Pogocki, D.; Horner, G.; Marciniak, B.; Schoneich, C.

2006-01-01

Sulfide radical cations (R 2 S +. ) have recently attracted considerable attention. In particular they are implicated in assorted biological electron transfers where they are likely intermediates in biological redox-processes. There is unambigous theoretical and experimental evidence that R 2 S +. can be stabilized through intramolecular complexation with nucleophiles that are present in neighboring groups. Reactions of this type are of special interest to biology when stabilization of sulfide radical cations derived from methionine, Met(>S +. ) occurs in peptides and proteins. The methionine (Met) residues in these biopolymers are susceptible to attack by Reactive Oxygen Species (ROS) during oxidative stress and biological aging. Moreover, the pathogenesis of some neurodegenerative diseases (Alzheimer's, Jacob-Creutzfeld's, and Parkinson's) seems to be strongly linked to the presence in brain tissue of β-amyloid peptide (βAP), human prion protein (hPrP), and an aggregated form of α-synuclein, respectively. These macro- molecules contain methionine(s) with βAP having a Met 35 residue in its C-terminal α-helical domain, hPrP having three out of nine Met-residues (namely Met 205 , Met 206 , and Met 213 ) located within its α-helical segments, and α-synuclein having four Met-residues. The effective neighboring-group interactions would likely involve nucleophilic functionalities in the side chain of amino acids residues. However, very often heteroatoms in peptide bonds are the only nucleophiles present in the vicinity of Met(>S +. ). In this regard, it was recently shown that such interactions play an important role in N-acetylmethione amide and in oligopeptides of the form N-Ac-Gly-Met-Gly and N-Ac-Gly-(Gly) 2 -Met-(Gly) 3 . Intramolecularly bonded sulfide radical cations, Met(>S +. ), were directly observed in these systems with the bonding partner being either the carbonyl oxygen or the amide nitrogen of a peptide bond. Cyclic dipeptides are suitable model

Spirit Pluralisme dalam Klenteng Sam Po Kong Semarang

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Edi Nurwahyu Julianto

2015-07-01

Full Text Available Klenteng Sam Po Kong has very deep meaning as a symbol of multi cultural; multi ethnic and multi religious. Klenteng Sam Po Kong has a different function, not only used by people with background religious Tri Dharma (Budha, Tao and Konghuchu, but also used by Javanese ethnic with different religious backgrounds. Between ethnic China and Java, mutual respect and tolerance run beliefs and rituals of each. More over, Klenteng Sam Po Kong is a form of pluralism which reflected the fact Sino Javanese Muslim Culture is preserved to date both of sightings physical culture and system cultural in the form of religious rites performed by ethnic China and Java.

The effects of an L-methionine combination supplement on ...

African Journals Online (AJOL)

Interventions. L-methionine combination supplement (L-methionine, vitamin B6, vitamin B12, folic acid and magnesium) or placebo containing potato starch. Main outcome measures. Incidence of URTS was recorded during the runner's preparation for an ultramarathon race (75 days) and recovery from the same (75 days).

Recognition of Ribosomal Protein L11 by the Protein Trimethyltransferase PrmA

Energy Technology Data Exchange (ETDEWEB)

Demirci,H.; Gregory, S.; Dahlberg, A.; Jogl, G.

2007-01-01

Bacterial ribosomal protein L11 is post-translationally trimethylated at multiple residues by a single methyltransferase, PrmA. Here, we describe four structures of PrmA from the extreme thermophile Thermus thermophilus. Two apo-PrmA structures at 1.59 and 2.3 {angstrom} resolution and a third with bound cofactor S-adenosyl-L-methionine at 1.75 {angstrom} each exhibit distinct relative positions of the substrate recognition and catalytic domains, revealing how PrmA can position the L11 substrate for multiple, consecutive side-chain methylation reactions. The fourth structure, the PrmA-L11 enzyme-substrate complex at 2.4 {angstrom} resolution, illustrates the highly specific interaction of the N-terminal domain with its substrate and places Lys39 in the PrmA active site. The presence of a unique flexible loop in the cofactor-binding site suggests how exchange of AdoMet with the reaction product S-adenosyl-L-homocysteine can occur without necessitating the dissociation of PrmA from L11. Finally, the mode of interaction of PrmA with L11 explains its observed preference for L11 as substrate before its assembly into the 50S ribosomal subunit.

THE MYTH OF MATERIAL SUCCESS AS REFLECTED IN SAM WALTON: MADE IN AMERICA-MY STORY

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Utut Kurniati

2015-12-01

Full Text Available American myth of material success had been orchestrated five basic beliefs that were reflected in Sam Walton’s biography, Sam Walton: Made in America-My Story. Those beliefs were: 1 Having a strong will to be successful man in America, Sam Walton was aware that the American democracy allowed its citizens to rise above any limitation in which they may have been born; 2 Then, he rose up from his limitation by hard work. His hard work successfully brought him to the riches and physical comforts; 3 He believed that those rewards came to those who were deserving of them (virtuous; 4 He also believed that those rewards came to those who had the drive and ambition to attain them. Therefore, he was optimistic to attain success in America; 5 Hard work to attain success made Sam Walton a lucky man who received good luck in his life. As a result, his dream of being a successful man in America came true. Keywords: the myth of material success, American dream, hard work

Partitioning of One-Carbon Units in Folate and Methionine Metabolism Is Essential for Neural Tube Closure

Directory of Open Access Journals (Sweden)

Kit-Yi Leung

2017-11-01

Full Text Available Summary: Abnormal folate one-carbon metabolism (FOCM is implicated in neural tube defects (NTDs, severe malformations of the nervous system. MTHFR mediates unidirectional transfer of methyl groups from the folate cycle to the methionine cycle and, therefore, represents a key nexus in partitioning one-carbon units between FOCM functional outputs. Methionine cycle inhibitors prevent neural tube closure in mouse embryos. Similarly, the inability to use glycine as a one-carbon donor to the folate cycle causes NTDs in glycine decarboxylase (Gldc-deficient embryos. However, analysis of Mthfr-null mouse embryos shows that neither S-adenosylmethionine abundance nor neural tube closure depend on one-carbon units derived from embryonic or maternal folate cycles. Mthfr deletion or methionine treatment prevents NTDs in Gldc-null embryos by retention of one-carbon units within the folate cycle. Overall, neural tube closure depends on the activity of both the methionine and folate cycles, but transfer of one-carbon units between the cycles is not necessary. : Leung at al. find that embryonic neural tube closure depends both on the supply of one-carbon units to the folate cycle from glycine cleavage and on the methionine cycle. In contrast, transfer of one-carbon units from the folate cycle to the methionine cycle by MTHFR is dispensable. Keywords: one-carbon metabolism, folic acid, neural tube defects, spina bifida, glycine cleavage system, non-ketotic hyperglycinemia, eye, Mthfr, Gldc

Elp3 and RlmN: A tale of two mitochondrial tail-anchored radical SAM enzymes in Toxoplasma gondii.

Science.gov (United States)

Padgett, Leah R; Lentini, Jenna M; Holmes, Michael J; Stilger, Krista L; Fu, Dragony; Sullivan, William J

2018-01-01

Radical S-adenosylmethionine (rSAM) enzymes use a 5'-deoxyadensyl 5'-radical to methylate a wide array of diverse substrates including proteins, lipids and nucleic acids. One such enzyme, Elongator protein-3 (TgElp3), is an essential protein in Toxoplasma gondii, a protozoan parasite that can cause life-threatening opportunistic disease. Unlike Elp3 homologues which are present in all domains of life, TgElp3 localizes to the outer mitochondrial membrane (OMM) via a tail-anchored trafficking mechanism in Toxoplasma. Intriguingly, we identified a second tail-anchored rSAM domain containing protein (TgRlmN) that also localizes to the OMM. The transmembrane domain (TMD) on Toxoplasma Elp3 and RlmN homologues is required for OMM localization and has not been seen beyond the chromalveolates. Both TgElp3 and TgRlmN contain the canonical rSAM amino acid sequence motif (CxxxCxxC) necessary to form the 4Fe-4S cluster required for tRNA modifications. In E. coli, RlmN is responsible for the 2-methlyadenosine (m2A) synthesis at purine 37 in tRNA while in S. cerevisiae, Elp3 is necessary for the formation of 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) at the wobble tRNA position. To investigate why these two rSAM enzymes localize to the mitochondrion in Toxoplasma, and whether or not TgRlmN and TgElp3 possess tRNA methyltransferase activity, a series of mutational and biochemical studies were performed. Overexpression of either TgElp3 or TgRlmN resulted in a significant parasite replication defect, but overexpression was tolerated if either the TMD or rSAM domain was mutated. Furthermore, we show the first evidence that Toxoplasma tRNAGlu contains the mcm5s2U modification, which is the putative downstream product generated by TgElp3 activity.

Mutagenic and cytotoxic properties of 6-thioguanine, S6-methylthioguanine, and guanine-S6-sulfonic acid.

Science.gov (United States)

Yuan, Bifeng; Wang, Yinsheng

2008-08-29

Thiopurine drugs, including 6-thioguanine ((S)G), 6-mercaptopurine, and azathioprine, are widely employed anticancer agents and immunosuppressants. The formation of (S)G nucleotides from the thiopurine prodrugs and their subsequent incorporation into nucleic acids are important for the drugs to exert their cytotoxic effects. (S)G in DNA can be methylated by S-adenosyl-l-methionine to give S(6)-methylthioguanine (S(6)mG) and oxidized by UVA light to render guanine-S(6)-sulfonic acid ((SO3H)G). Here, we constructed single-stranded M13 shuttle vectors carrying a (S)G, S(6)mG, or (SO3H)G at a unique site and allowed the vectors to propagate in wild-type and bypass polymerase-deficient Escherichia coli cells. Analysis of the replication products by using the competitive replication and adduct bypass and a slightly modified restriction enzyme digestion and post-labeling assays revealed that, although none of the three thionucleosides considerably blocked DNA replication in all transfected E. coli cells, both S(6)mG and (SO3H)G were highly mutagenic, which resulted in G-->A mutation at frequencies of 94 and 77%, respectively, in wild-type E. coli cells. Deficiency in bypass polymerases does not result in alteration of mutation frequencies of these two lesions. In contrast to what was found from previous steady-state kinetic analysis, our data demonstrated that 6-thioguanine is mutagenic, with G-->A transition occurring at a frequency of approximately 10%. The mutagenic properties of 6-thioguanine and its derivatives revealed in the present study offered important knowledge about the biological implications of these thionucleosides.

1H NMR studies of substrate hydrogen exchange reactions catalyzed by L-methionine gamma-lyase

International Nuclear Information System (INIS)

Esaki, N.; Nakayama, T.; Sawada, S.; Tanaka, H.; Soda, K.

1985-01-01

Hydrogen exchange reactions of various L-amino acids catalyzed by L-methionine gamma-lyase (EC 4.4.1.11) have been studied. The enzyme catalyzes the rapid exchange of the alpha- and beta-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium from the solvent. The rate of alpha-hydrogen exchange was about 40 times faster than that of the enzymatic elimination reaction of the sulfur-containing amino acids. The enzyme also catalyzes the exchange reaction of alpha- and beta-hydrogens of the straight-chain L-amino acids which are not susceptible to elimination. The exchange rates of the alpha-hydrogen and the total beta-hydrogens of L-alanine and L-alpha-aminobutyrate with deuterium followed first-order kinetics. For L-norvaline, L-norleucine, S-methyl-L-cysteine, and L-methionine, the rate of alpha-hydrogen exchange followed first-order kinetics, but the rate of total beta-hydrogen exchange decreased due to a primary isotope effect at the alpha-position. L-Phenylalanine and L-tryptophan slowly underwent alpha-hydrogen exchange. The pro-R hydrogen of glycine was deuterated stereospecifically

Sam68 promotes Schwann cell proliferation by enhancing the PI3K/Akt pathway and acts on regeneration after sciatic nerve crush

Energy Technology Data Exchange (ETDEWEB)

Wu, Weijie, E-mail: 459586768@qq.com; Liu, Yuxi, E-mail: 924013616@qq.com; Wang, Youhua, E-mail: wyouhua1516@163.com

2016-05-13

Sam68 (Src-associated in mitosis of 68 kD), a KH domain RNA-binding protein, is not only important in signaling transduction cascades, but crucial in a variety of cellular processes. Sam68 is reported to be involved in the phospoinositide3-kinase (PI3K) and nuclear factor-kappa B (NF-κB) signaling pathways, and it is closely associated with cell proliferation, RNA metabolism, and tumor progression. However, we know little about the role of Sam68 during peripheral nervous system injury and regeneration. In this study, we investigated the expression of Sam68 and its biological significances in sciatic nerve crush. Interestingly, we found Sam68 had a co-localization with S100 (Schwann cell marker). Moreover, after crush, Sam68 had a spatiotemporal protein expression, which was in parallel with proliferation cell nuclear antigen (PCNA). In vitro, we also observed increased expression of Sam68 during the process of TNF-α-induced Schwann cell proliferation model. Besides, flow cytometry analyses, CCK-8, and EDU were all performed with the purpose of investigating the role of Sam68 in the regulation of Schwann cell proliferation. Even more importantly, we discovered that Sam68 could enhance the phosphorylation of Akt while LY294002 (a PI3K inhibitor) obviously reversed Sam68-induced cell proliferation. Finally, we detected the variance during regeneration progress through the rat walk footprint test. In summary, all these evidences demonstrated that Sam68 might participate in Schwann cell proliferation partially via PI3K/Akt pathway and also regulate regeneration after sciatic nerve crush. -- Highlights: •The dynamic changes and location of Sam68 after sciatic nerve crush. •Sam68 promoted Schwann cell proliferation via PI3K/Akt pathway. •Sam68 modulated functional recovery after sciatic nerve crush.

Sam68 promotes Schwann cell proliferation by enhancing the PI3K/Akt pathway and acts on regeneration after sciatic nerve crush

International Nuclear Information System (INIS)

Wu, Weijie; Liu, Yuxi; Wang, Youhua

2016-01-01

Sam68 (Src-associated in mitosis of 68 kD), a KH domain RNA-binding protein, is not only important in signaling transduction cascades, but crucial in a variety of cellular processes. Sam68 is reported to be involved in the phospoinositide3-kinase (PI3K) and nuclear factor-kappa B (NF-κB) signaling pathways, and it is closely associated with cell proliferation, RNA metabolism, and tumor progression. However, we know little about the role of Sam68 during peripheral nervous system injury and regeneration. In this study, we investigated the expression of Sam68 and its biological significances in sciatic nerve crush. Interestingly, we found Sam68 had a co-localization with S100 (Schwann cell marker). Moreover, after crush, Sam68 had a spatiotemporal protein expression, which was in parallel with proliferation cell nuclear antigen (PCNA). In vitro, we also observed increased expression of Sam68 during the process of TNF-α-induced Schwann cell proliferation model. Besides, flow cytometry analyses, CCK-8, and EDU were all performed with the purpose of investigating the role of Sam68 in the regulation of Schwann cell proliferation. Even more importantly, we discovered that Sam68 could enhance the phosphorylation of Akt while LY294002 (a PI3K inhibitor) obviously reversed Sam68-induced cell proliferation. Finally, we detected the variance during regeneration progress through the rat walk footprint test. In summary, all these evidences demonstrated that Sam68 might participate in Schwann cell proliferation partially via PI3K/Akt pathway and also regulate regeneration after sciatic nerve crush. -- Highlights: •The dynamic changes and location of Sam68 after sciatic nerve crush. •Sam68 promoted Schwann cell proliferation via PI3K/Akt pathway. •Sam68 modulated functional recovery after sciatic nerve crush.

Formation of S-(carboxymethyl)-cysteine in rat liver mitochondrial proteins: effects of caloric and methionine restriction.

Science.gov (United States)

Naudí, Alba; Jové, Mariona; Cacabelos, Daniel; Ayala, Victoria; Cabre, Rosanna; Caro, Pilar; Gomez, José; Portero-Otín, Manuel; Barja, Gustavo; Pamplona, Reinald

2013-02-01

Maillard reaction contributes to the chemical modification and cross-linking of proteins. This process plays a significant role in the aging process and determination of animal longevity. Oxidative conditions promote the Maillard reaction. Mitochondria are the primary site of oxidants due to the reactive molecular species production. Mitochondrial proteome cysteine residues are targets of oxidative attack due to their specific chemistry and localization. Their chemical, non-enzymatic modification leads to dysfunctional proteins, which entail cellular senescence and organismal aging. Previous studies have consistently shown that caloric and methionine restrictions, nutritional interventions that increase longevity, decrease the rate of mitochondrial oxidant production and the physiological steady-state levels of markers of oxidative damage to macromolecules. In this scenario, we have detected S-(carboxymethyl)-cysteine (CMC) as a new irreversible chemical modification in mitochondrial proteins. CMC content in mitochondrial proteins significantly correlated with that of the lysine-derived analog N (ε)-(carboxymethyl)-lysine. The concentration of CMC is, however, one order of magnitude lower compared with CML likely due in part to the lower content of cysteine with respect to lysine of the mitochondrial proteome. CMC concentrations decreases in liver mitochondrial proteins of rats subjected to 8.5 and 25 % caloric restriction, as well as in 40 and 80 % methionine restriction. This is associated with a concomitant and significant increase in the protein content of sulfhydryl groups. Data presented here evidence that CMC, a marker of Cys-AGE formation, could be candidate as a biomarker of mitochondrial damage during aging.

Robotic synthesis of [carbon-11]methionine

International Nuclear Information System (INIS)

Korsakov, M.V.; Kisselev, M.Y.; Solovyov, D.; Horti, A.G.; Vasilev, A.; Nilsson, L.E.; Ulin, J.

1992-01-01

[ 11 C]Methionine was prepared in a fully automated robotic synthesis, using the SCANDITRONIX robotic system starting from [ 11 C]I and homocysteine thiolactone. The product was purified using solid phase extraction on anionic exchange cartridges. The decay corrected yield was 60% based on CH 3 I and 16 min synthesis time. The radiochemical purity was 98-99% and the chemical impurities were: homocysteine 0.05-0.07 mg/ml, homocystine 0.005 mg/ml, 'cold' methionine 0.03-0.05 mg/ml, and homocysteine thiolactone 0.0008-0.002 mg/ml. The total procedure takes 30 min from EOB. (author) 6 figs., 3 tabs

Methionine kinetics and balance at the 1985 FAO/WHO/UNU intake requirement in adult men studied with L-[2H3-methyl-1-13C]methionine as a tracer

International Nuclear Information System (INIS)

Young, V.R.; Wagner, D.A.; Burini, R.; Storch, K.J.

1991-01-01

The upper range of the requirement for methionine plus cystine in healthy adults was proposed in 1985 by FAO/WHO/UNU to be 13 mg.kg body wt-1.d-1. To explore the validity of this estimate, five healthy, young adult men were given for 7 d a diet based on an L-amino acid mixture supplying 13 mg methionine.kg-1.d-1 (87 mumol.kg-1.d-1) without cystine. Constant intravenous infusions of L-[2H3-methyl-1-13C]methionine were given on days 5 and 7 while subjects were in the fed and postabsorptive states, respectively. Estimates were made of methionine oxidation, and daily methionine balance was derived from the intake-oxidation data. For the five subjects, methionine balances were -0.9, +0.7, +3.5, -3.1, and -3.8 mg kg-1.d-1, or -6, +5, +23, -21, and -26 mumol.kg-1.d-1. These findings lead to the conclusion that the upper range of the requirement for methionine plus cystine probably exceeds 13 mg.kg-1.d-1 in healthy young adults. The implications of this conclusion for establishing an appropriate amount of sulfur amino acids in an amino acid requirement pattern for adults is discussed

Integration, Validation, and Application of a PV Snow Coverage Model in SAM

Energy Technology Data Exchange (ETDEWEB)

Freeman, Janine M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ryberg, David Severin [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-01

Due to the increasing deployment of PV systems in snowy climates, there is significant interest in a method capable of estimating PV losses resulting from snow coverage that has been verified for a variety of system designs and locations. Many independent snow coverage models have been developed over the last 15 years; however, there has been very little effort verifying these models beyond the system designs and locations on which they were based. Moreover, major PV modeling software products have not yet incorporated any of these models into their workflows. In response to this deficiency, we have integrated the methodology of the snow model developed in the paper by Marion et al. (2013) into the National Renewable Energy Laboratory's (NREL) System Advisor Model (SAM). In this work, we describe how the snow model is implemented in SAM and we discuss our demonstration of the model's effectiveness at reducing error in annual estimations for three PV arrays. Next, we use this new functionality in conjunction with a long term historical data set to estimate average snow losses across the United States for two typical PV system designs. The open availability of the snow loss estimation capability in SAM to the PV modeling community, coupled with our results of the nationwide study, will better equip the industry to accurately estimate PV energy production in areas affected by snowfall.

Dry-extrusion of Asian Carp to supplement natural methionine for organic poultry production

Science.gov (United States)

Methionine, a sulfur containing amino acid, is essential for healthy poultry production. Synthetic methionine is commonly used as a supplement in conventional poultry. However, for organic poultry in the United States, a natural, cost effective source of methionine that can replace synthetic methion...

Motor coordination defects in mice deficient for the Sam68 RNA-binding protein.

Science.gov (United States)

Lukong, Kiven E; Richard, Stéphane

2008-06-03

The role of RNA-binding proteins in the central nervous system and more specifically their role in motor coordination and learning are poorly understood. We previously reported that ablation of RNA-binding protein Sam68 in mice results in male sterility and delayed mammary gland development and protection against osteoporosis in females. Sam68 however is highly expressed in most regions of the brain especially the cerebellum and thus we investigated the cerebellar-related manifestations in Sam68-null mice. We analyzed the mice for motor function, sensory function, and learning and memory abilities. Herein, we report that Sam68-null mice have motor coordination defects as assessed by beam walking and rotorod performance. Forty-week-old Sam68-null mice (n=12) were compared to their wild-type littermates (n=12). The Sam68-null mice exhibited more hindpaw faults in beam walking tests and fell from the rotating drum at lower speeds and prematurely compared to the wild-type controls. The Sam68-null mice were, however, normal for forelimb strength, tail-hang reflex, balance test, grid walking, the Morris water task, recognition memory, visual discrimination, auditory stimulation and conditional taste aversion. Our findings support a role for Sam68 in the central nervous system in the regulation of motor coordination.

Radiation streaming with SAM-CE

International Nuclear Information System (INIS)

De Gangi, N.; Cohen, M.O.; Waluschka, E.; Steinberg, H.A.

1980-01-01

The SAM-CE Monte Carlo code has been employed to calculate doses, due to neutron streaming, on the operating floor and other locations of the Millstone Unit II Nuclear Power Facility. Calculated results were compared against measured doses

Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine

Directory of Open Access Journals (Sweden)

Marc Enßle

2012-03-01

Full Text Available Methionine, S-benzylcysteine and S-allylcysteine were converted into 2-diazo-3-oxo-4-phthalimidocarboxylic esters 8a–c in three steps. Upon rhodium-catalysed dediazoniation, two intramolecular carbenoid reactions competed, namely the formation of a cyclic sulfonium ylide and that of a six-ring carbonyl ylide. The S-methyl and S-benzyl ylides 12a and b could be isolated, while S-allyl ylide 12c underwent a [2,3]-sigmatropic rearrangement. The short-lived carbonyl ylides derived from methionine and S-benzylcysteine formed head-to-tail dimers by a [3 + 3]-cycloaddition and could be trapped with external dipolarophiles, while the S-allyl derivative 14c yielded the pentacyclic compound 17 by an intramolecular [3 + 2]-cycloaddition reaction.

SAM : an experiment dedicated to the Carbon Quest at Mars

Science.gov (United States)

Coll, Patrice; Mahaffy, Paul; Webster, Chris; Cabane, Michel; Tan, F.; Coscia, D.; Nolan, T.; Rahen, E.; Teinturier, S.; Goutail, J. P.; Martin, D.; Montaron, C.; Galic, A.

SAM is a suite of instruments that will be onboard the Mars Science Laboratory (MSL) rover. The SAM team consist of scientists and engineers at GSFC, U. Paris/CNRS, JPL, and Honeybee Robotics, along with many additional external partners. SAM's five science goals will address three of the most fundamental questions about the ability of Mars to support life -past, present, and future. Question 1: What does the inventory of carbon compounds near the surface of Mars tell us about its potential habitability? 1.Goal 1: Survey carbon compound sources and evaluate their possible mechanism of formation and destruction. 2.Goal 2: Search for organic compounds of biotic and prebiotic importance expecially methane. Question 2: What are the chemical and isotopic states of the lighter elements in the solids and atmosphere of Mars and what do they tell us about its potential habitability? 1.Goal 3: Reveal the chemical and isotopic state of elements (i.e., N, H, O, S and others) that are important for life as we know it. 2.Goal 4: Evaluate the habitability of Mars by studying its atmospheric chemistry and the composition of trace species that are evidence of interactions between the atmosphere and soil. Question 3: Were past habitability conditions different from today's? 1.Goal 5: Understand atmospheric and climatic evolution through measurements of noble gas and light element isotopes.

On LAM's and SAM's for Halley's rotation

Science.gov (United States)

Peale, Stanton J.

1992-01-01

Non principal axis rotation for comet Halley is inferred from dual periodicities evident in the observations. The modes where the spin axis precesses around the axis of minimum moment of inertia (long axis mode or LAM) and where it precesses around the axis of maximum moment of inertia (short axis mode or SAM) are described from an inertial point of view. The currently favored LAM model for Halley's rotation state satisfies observational and dynamical constraints that apparently no SAM can satisfy. But it cannot reproduce the observed post perihelion brightening through seasonal illumination of localized sources on the nucleus, whereas a SAM can easily produce post or pre perihelion brightening by this mechanism. However, the likelihood of a LAM rotation for elongated nuclei of periodic comets such as Halley together with Halley's extreme post perihelion behavior far from the Sun suggest that Halley's post perihelion brightening may be due to effects other than seasonal illumination of localized sources, and therefore such brightening may not constrain its rotation state.

Evolved Gas Analyses of the Murray Formation in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars (SAM) Instrument

Science.gov (United States)

Sutter, B.; McAdam, A. C.; Rampe, E. B.; Thompson, L. M.; Ming, D. W.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Stern, J. C.; Eigenbrode, J. L.; Archer, P. D.

2017-01-01

The Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory rover has analyzed 13 samples from Gale Crater. All SAM-evolved gas analyses have yielded a multitude of volatiles (e.g., H2O, SO2, H2S, CO2, CO, NO, O2, HCl) [1- 6]. The objectives of this work are to 1) Characterize recent evolved SO2, CO2, O2, and NO gas traces of the Murray formation mudstone, 2) Constrain sediment mineralogy/composition based on SAM evolved gas analysis (SAM-EGA), and 3) Discuss the implications of these results relative to understanding the geological history of Gale Crater.

The role of catechol-O-methyltransferase in catechol-enhanced erythroid differentiation of K562 cells.

Science.gov (United States)

Suriguga; Li, Xiao-Fei; Li, Yang; Yu, Chun-Hong; Li, Yi-Ran; Yi, Zong-Chun

2013-12-15

Catechol is widely used in pharmaceutical and chemical industries. Catechol is also one of phenolic metabolites of benzene in vivo. Our previous study showed that catechol improved erythroid differentiation potency of K562 cells, which was associated with decreased DNA methylation in erythroid specific genes. Catechol is a substrate for the catechol-O-methyltransferase (COMT)-mediated methylation. In the present study, the role of COMT in catechol-enhanced erythroid differentiation of K562 cells was investigated. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation and induced mRNA expression of erythroid specific genes in K562 cells. Treatment with catechol caused a time- and concentration-dependent increase in guaiacol concentration in the medium of cultured K562 cells. When COMT expression was knocked down by COMT shRNA expression in K562 cells, the production of guaiacol significantly reduced, and the sensitivity of K562 cells to cytotoxicity of catechol significantly increased. Knockdown of COMT expression by COMT shRNA expression also eliminated catechol-enhanced erythroid differentiation of K562 cells. In addition, the pre-treatment with methyl donor S-adenosyl-L-methionine or its demethylated product S-adenosyl-L-homocysteine induced a significant increase in hemin-induced Hb synthesis in K562 cells and the mRNA expression of erythroid specific genes. These findings indicated that O-methylation catalyzed by COMT acted as detoxication of catechol and involved in catechol-enhanced erythroid differentiation of K562 cells, and the production of S-adenosyl-L-homocysteine partly explained catechol-enhanced erythroid differentiation. © 2013.

Utility of “1”1C -methionine PET/CT in neuro-oncology

International Nuclear Information System (INIS)

Casas Parera, I.; Igirio Gamero, J.L.; Báez, A.; Tafur Canabal, J.G.; Báez, M.; Kuchkaryan, V.; B lumenkrantz, Y.; Bruno, G.

2013-01-01

Positron emission tomography (PET) with “1”1C-methionine (“1”1C-methionine PET/CT) is a new technique used to evaluate primary central nervous system (CNS) tumors. We describe our experience regarding the first 4 patients with glial tumors and “1”1C-methionine PET/CT. This is a descriptive, observational and prospective study of 4 patients between 38-50 years of age, with different gliomas (WHO classification). MRI and “1”1C-methionine PET/CT were performed in all cases. Case 1, gliomatosis cerebri grade II post-radiotherapy. Case 2, oligodendroglioma grade II diagnosed and treated with radiotherapy in 1993. Case 3, glioblastoma grade IV post-radiotherapy + temozolomide. Case 4, anaplastic oligoastrocytoma grade III post-radiotherapy + temozolomide. The pattern of “1”1C-methionine uptake compared with MRI showed tumor progression in cases 1, 3 and 4, and in case 2 showed uptake although the final diagnosis was pseudoprogression. Unlike “1”8fluordeoxiglucose PET/TC, “1”1C-methionine uptake in normal brain tissue and pseudoprogression is low, and gliomas are displayed as metabolically active areas. The “1”1C-methionine PET/CT provided valuable information on the tumoral behavior and extension, although in one case presented did not differentiate tumor progression from pseudoprogression. “1”1C-methionine PET/CT could be a useful tool in the study and follow-up to patients with gliomas. (authors) [es

Digestible methionine + cystine requirement for Nile tilapia from 550 to 700 g

Directory of Open Access Journals (Sweden)

Mariana Michelato

2013-01-01

Full Text Available This trial was conducted to determine the dietary digestible methionine + cystine requirement of Nile tilapia (550 to 700 g based on the ideal protein concept. Six hundred fish were distributed in a completely randomized design with five treatments and four replicates, with 30 fish per experimental unit. The fish were fed diets containing approximately 262 g of digestible protein/kg, 3,040 kcal of digestible energy/kg and 7.90, 9.40, 10.90, 12.40 or 13.90 g of methionine + cystine/kg. The fish were hand-fed three times a day until apparent satiation for 30 days. No effects of dietary methionine + cystine on feed conversion ratio, daily protein deposition, whole body moisture, fillet moisture, crude protein, ether extract and ash, plasmatic HDL and LDL cholesterol were observed. Dietary methionine resulted in a linear increase in whole body protein and linear reduction in lipid deposition rate, hepatosomatic index, whole body ether extract and ash, plasmatic total cholesterol, plasmatic total lipids and plasmatic triglycerides. According to the Linear Response Plateau, the daily weight gain and fillet yield increased up to a level of 9.00 and 9.90 g methionine + cystine/kg of diet, respectively. The digestible methionine + cystine requirement of Nile tilapia is 9.00 g/kg for weight gain and 9.90 g/kg for fillet yield, corresponding to methionine + cystine:lysine ratios of 0.60 and 0.66, respectively.

Different Levels of Digestible Methionine on Performance of Broiler Starter

Directory of Open Access Journals (Sweden)

WL Bryden

2010-01-01

Full Text Available Dietary protein and amino acid supply is the most expensive component of poultry diets. Therefore several efforts made by the industry to minimize the cost of the protein portion of the diet. Accordingly, there has been a recent move to use digestible amino acid values in the formulation of poultry diets. The efficiency of protein utilization depends to a large extent on the amino acid composition of the diet. The study was conducted to determine the digestible methionine requirement of broilers during the starter periods. One hundred and seventy five (175 chicks were allocated to 5 treatments with five replicates of seven chicks per replicate in a completely randomized design. Chicks were fed experimental diets from one day old to 21 days of age. Dietary treatments included 5 titrated levels each of digestible methionine (3.0, 4.5, 6.0, 7.5, and 9.0 g/kg diet added to a basal diet. The allowance of digestible methionine, rather than digestible sulphur amino acids was used in formulating the diets. Supplemental synthetic DL-Methionine which were considered to be 100% digestible were added to diets to obtain the concentration of the digestible amino acid. Each week until the conclusion of the trial, birds were individually weighed, feed intake per pen was measured, and feed conversion ratio (FCR was computed. This study suggested that the digestible methionine requirement for broiler starter is 4.7 g/kg for optimal body weight gain and 4.6 g/kg for optimal feed conversion ratio. (Animal Production 12(1: 6-11 (2010Key Words: amino acid, broiler, digestible, methionine, starter

Mutations at the S1 sites of methionine aminopeptidases from Escherichia coli and Homo sapiens reveal the residues critical for substrate specificity.

Science.gov (United States)

Li, Jing-Ya; Cui, Yong-Mei; Chen, Ling-Ling; Gu, Min; Li, Jia; Nan, Fa-Jun; Ye, Qi-Zhuang

2004-05-14

Methionine aminopeptidase (MetAP) catalyzes the removal of methionine from newly synthesized polypeptides. MetAP carries out this cleavage with high precision, and Met is the only natural amino acid residue at the N terminus that is accepted, although type I and type II MetAPs use two different sets of residues to form the hydrophobic S1 site. Characteristics of the S1 binding pocket in type I MetAP were investigated by systematic mutation of each of the seven S1 residues in Escherichia coli MetAP type I (EcMetAP1) and human MetAP type I (HsMetAP1). We found that Tyr-65 and Trp-221 in EcMetAP1, as well as the corresponding residues Phe-197 and Trp-352 in HsMetAP1, were essential for the hydrolysis of a thiopeptolide substrate, Met-S-Gly-Phe. Mutation of Phe-191 to Ala in HsMetAP1 caused inactivity in contrast to the full activity of EcMetAP1(Y62A), which may suggest a subtle difference between the two type I enzymes. The more striking finding is that mutation of Cys-70 in EcMetAP1 or Cys-202 in HsMetAP1 opens up the S1 pocket. The thiopeptolides Leu-S-Gly-Phe and Phe-S-Gly-Phe, with previously unacceptable Leu or Phe as the N-terminal residue, became efficient substrates of EcMetAP1(C70A) and HsMetAP1(C202A). The relaxed specificity shown in these S1 site mutants for the N-terminal residues was confirmed by hydrolysis of peptide substrates and inhibition by reaction products. The structural features at the enzyme active site will be useful information for designing specific MetAP inhibitors for therapeutic applications.

Effects of Glycine, Water, Ammonia, and Ammonium Bicarbonate on the Oligomerization of Methionine

Science.gov (United States)

Huang, Rui; Furukawa, Yoshihiro; Otake, Tsubasa; Kakegawa, Takeshi

2017-06-01

The abiotic oligomerization of amino acids may have created primordial, protein-like biological catalysts on the early Earth. Previous studies have proposed and evaluated the potential of diagenesis for the amino acid oligomerization, simulating the formation of peptides that include glycine, alanine, and valine, separately. However, whether such conditions can promote the formation of peptides composed of multiple amino acids remains unclear. Furthermore, the chemistry of pore water in sediments should affect the oligomerization and degradation of amino acids and oligomers, but these effects have not been studied extensively. In this study, we investigated the effects of water, ammonia, ammonium bicarbonate, pH, and glycine on the oligomerization and degradation of methionine under high pressure (150 MPa) and high temperature conditions (175 °C) for 96 h. Methionine is more difficult to oligomerize than glycine and methionine dimer was formed in the incubation of dry powder of methionine. Methionine oligomers as long as trimers, as well as methionylglycine and glycylmethionine, were formed under every condition with these additional compounds. Among the compounds tested, the oligomerization reaction rate was accelerated by the presence of water and by an increase in pH. Ammonia also increased the oligomerization rate but consumed methionine by side reactions and resulted in the rapid degradation of methionine and its peptides. Similarly, glycine accelerated the oligomerization rate of methionine and the degradation of methionine, producing water, ammonia, and bicarbonate through its decomposition. With Gly, heterogeneous dimers (methionylglycine and glycylmethionine) were formed in greater amounts than with other additional compounds although smaller amount of these heterogeneous dimers were formed with other additional compounds. These results suggest that accelerated reaction rates induced by water and co-existing reactive compounds promote the oligomerization

Alternatively Spliced Methionine Synthase in SH-SY5Y Neuroblastoma Cells: Cobalamin and GSH Dependence and Inhibitory Effects of Neurotoxic Metals and Thimerosal

Directory of Open Access Journals (Sweden)

Mostafa Waly

2016-01-01

Full Text Available The folate and cobalamin (Cbl- dependent enzyme methionine synthase (MS is highly sensitive to oxidation and its activity affects all methylation reactions. Recent studies have revealed alternative splicing of MS mRNA in human brain and patient-derived fibroblasts. Here we show that MS mRNA in SH-SY5Y human neuroblastoma cells is alternatively spliced, resulting in three primary protein species, thus providing a useful model to examine cofactor dependence of these variant enzymes. MS activity was dependent upon methylcobalamin (MeCbl or the combination of hydroxocobalamin (OHCbl and S-adenosylmethionine (SAM. OHCbl-based activity was eliminated by depletion of the antioxidant glutathione (GSH but could be rescued by provision of either glutathionylcobalamin (GSCbl or MeCbl. Pretreatment of cells with lead, arsenic, aluminum, mercury, or the ethylmercury-containing preservative thimerosal lowered GSH levels and inhibited MS activity in association with decreased uptake of cysteine, which is rate-limiting for GSH synthesis. Thimerosal treatment decreased cellular levels of GSCbl and MeCbl. These findings indicate that the alternatively spliced form of MS expressed in SH-SY5Y human neuronal cells is sensitive to inhibition by thimerosal and neurotoxic metals, and lower GSH levels contribute to their inhibitory action.

Preparation, crystallization and preliminary X-ray analysis of the methionine synthase (MetE) from Streptococcus mutans

International Nuclear Information System (INIS)

Fu, Tian-Min; Zhang, Xiao-Yan; Li, Lan-Fen; Liang, Yu-He; Su, Xiao-Dong

2006-01-01

Methionine synthase (MetE) from S. mutans was expressed, purified and crystallized. Diffraction data have been collected to 2.2 Å resolution. The Streptococcus mutans metE gene encodes methionine synthase (MetE), which catalyzes the direct transfer of a methyl group from methyltetrahydrofolate to homocysteine in the last step of methionine synthesis. metE was cloned into pET28a and the gene product was expressed at high levels in the Escherichia coli strain BL21 (DE3). MetE was purified to homogeneity using Ni 2+ -chelating chromatography followed by size-exclusion chromatography. Crystals of the protein were obtained by the hanging-drop vapour-diffusion method and diffracted to 2.2 Å resolution. The crystal belongs to space group P2 1 , with unit-cell parameters a = 52.85, b = 99.48, c = 77.88 Å, β = 94.55°

Egg quality of quails fed low methionine diet supplemented with betaine

Science.gov (United States)

Ratriyanto, A.; Indreswari, R.; Dewanti, R.; Wahyuningsih, S.

2018-03-01

This experiment investigated the effect of betaine supplementation to low methionine diet on egg quality of quails. A total of 340 laying quails (Coturnix coturnix japonica) was divided into 4 dietary treatments with 5 replicates of 17 quails each. The experiment was assigned in a completely randomized design. The four dietary treatments were the low methionine diet (0.3% methionine) without betaine supplementation and the low methionine diet supplemented with 0.07, 0.14, and 0.21% betaine. The experimental diets were applied for 8 weeks and the egg quality traits were measured at the age of 16 and 20 weeks. The data were subjected to analysis of variance, and when the treatment indicated significant effect, it was continued to orthogonal polynomial test to determine the optimum level of betaine. Increasing dietary levels of betaine increased the fat content of the egg with the linear regression of y = 11.0949 + 4.1914x (R2 = 0.18). However, supplementation of betaine did not affect protein content, yolk, albumen, and eggshell percentage. It can be concluded that betaine supplementation up to 0.21% to low methionine diet only had little effect in improving the quality traits of quail eggs.

Parabolic Trough Reference Plant for Cost Modeling with the Solar Advisor Model (SAM)

Energy Technology Data Exchange (ETDEWEB)

Turchi, C.

2010-07-01

This report describes a component-based cost model developed for parabolic trough solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), assisted by WorleyParsons Group Inc., for use with NREL's Solar Advisor Model (SAM). This report includes an overview and explanation of the model, two summary contract reports from WorleyParsons, and an Excel spreadsheet for use with SAM. The cost study uses a reference plant with a 100-MWe capacity and six hours of thermal energy storage. Wet-cooling and dry-cooling configurations are considered. The spreadsheet includes capital and operating cost by component to allow users to estimate the impact of changes in component costs.

Increasing levels of dietary crystalline methionine affect plasma methionine profiles, ammonia excretion, and the expression of genes related to the hepatic intermediary metabolism in rainbow trout (Oncorhynchus mykiss)

DEFF Research Database (Denmark)

Rolland, Marine; Skov, Peter Vilhelm; Larsen, Bodil Katrine

2016-01-01

Strictly carnivorous fish with high requirements for dietary protein, such as rainbow trout (Oncorhynchus mykiss) are interesting models for studying the role of amino acids as key regulators of intermediary metabolism. Methionine is an essential amino acid for rainbow trout, and works as a signa......Strictly carnivorous fish with high requirements for dietary protein, such as rainbow trout (Oncorhynchus mykiss) are interesting models for studying the role of amino acids as key regulators of intermediary metabolism. Methionine is an essential amino acid for rainbow trout, and works...... as a signalling factor in different metabolic pathways. The study investigated the effect of increasing dietary methionine intake on the intermediary metabolism in the liver of juvenile rainbow trout. For this purpose, five diets were formulated with increasing methionine levels from 0.60 to 1.29% dry matter....... The diets were fed in excess for six weeks before three sampling campaigns carried out successively to elucidate (i) the hepatic expression of selected genes involved in lipid, glucose and amino acid metabolism; (ii) the postprandial ammonia excretion; and (iii) the postprandial plasma methionine...

Adenosine kinase deficiency disrupts the methionine cycle and causes hypermethioninemia, encephalopathy, and abnormal liver function.

Science.gov (United States)

Bjursell, Magnus K; Blom, Henk J; Cayuela, Jordi Asin; Engvall, Martin L; Lesko, Nicole; Balasubramaniam, Shanti; Brandberg, Göran; Halldin, Maria; Falkenberg, Maria; Jakobs, Cornelis; Smith, Desiree; Struys, Eduard; von Döbeln, Ulrika; Gustafsson, Claes M; Lundeberg, Joakim; Wedell, Anna

2011-10-07

Four inborn errors of metabolism (IEMs) are known to cause hypermethioninemia by directly interfering with the methionine cycle. Hypermethioninemia is occasionally discovered incidentally, but it is often disregarded as an unspecific finding, particularly if liver disease is involved. In many individuals the hypermethioninemia resolves without further deterioration, but it can also represent an early sign of a severe, progressive neurodevelopmental disorder. Further investigation of unclear hypermethioninemia is therefore important. We studied two siblings affected by severe developmental delay and liver dysfunction. Biochemical analysis revealed increased plasma levels of methionine, S-adenosylmethionine (AdoMet), and S-adenosylhomocysteine (AdoHcy) but normal or mildly elevated homocysteine (Hcy) levels, indicating a block in the methionine cycle. We excluded S-adenosylhomocysteine hydrolase (SAHH) deficiency, which causes a similar biochemical phenotype, by using genetic and biochemical techniques and hypothesized that there was a functional block in the SAHH enzyme as a result of a recessive mutation in a different gene. Using exome sequencing, we identified a homozygous c.902C>A (p.Ala301Glu) missense mutation in the adenosine kinase gene (ADK), the function of which fits perfectly with this hypothesis. Increased urinary adenosine excretion confirmed ADK deficiency in the siblings. Four additional individuals from two unrelated families with a similar presentation were identified and shown to have a homozygous c.653A>C (p.Asp218Ala) and c.38G>A (p.Gly13Glu) mutation, respectively, in the same gene. All three missense mutations were deleterious, as shown by activity measurements on recombinant enzymes. ADK deficiency is a previously undescribed, severe IEM shedding light on a functional link between the methionine cycle and adenosine metabolism. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Using Raman spectroscopy to understand the origin of the phase transition observed in the crystalline sulfur based amino acid l-methionine

DEFF Research Database (Denmark)

Lima, José A.; Freire, P.T.C.; Melo, F.E.A.

2013-01-01

We present the Raman spectra of l-methionine (C5 H11 NO2 S) monocrystals obtained in the spectral region ranging from 3200 to 50 cm-1 at temperatures from 20 to 375 K. We investigated the dynamics of the different functional groups in l-methionine and related their behaviour to the structural tra...

Identification of trans-acting factors regulating SamDC expression in Oryza sativa

Energy Technology Data Exchange (ETDEWEB)

Basu, Supratim, E-mail: supratim_genetics@yahoo.co.in [Department of Crop Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 (United States); Division of Plant Biology, Bose Institute, Kolkata (India); Roychoudhury, Aryadeep [Post Graduate Department of Biotechnology, St. Xavier' s College (Autonomous), 30, Mother Teresa Sarani, Kolkata - 700016, West Bengal (India); Sengupta, Dibyendu N. [Division of Plant Biology, Bose Institute, Kolkata (India)

2014-03-07

Highlights: • Identification of cis elements responsible for SamDC expression by in silico analysis. • qPCR analysis of SamDC expression to abiotic and biotic stress treatments. • Detection of SamDC regulators using identified cis-elements as probe by EMSA. • Southwestern Blot analysis to predict the size of the trans-acting factors. - Abstract: Abiotic stress affects the growth and productivity of crop plants; to cope with the adverse environmental conditions, plants have developed efficient defense machinery comprising of antioxidants like phenolics and flavonoids, and osmolytes like polyamines. SamDC is a key enzyme in the polyamine biosynthesis pathway in plants. In our present communication we have done in silico analysis of the promoter region of SamDC to look for the presence of different cis-regulatory elements contributing to its expression. Based on the presence of different cis-regulatory elements we completed comparative analysis of SamDC gene expression in rice lamina of IR-29 and Nonabokra by qPCR in response to the abiotic stress treatments of salinity, drought, cold and the biotic stress treatments of ABA and light. Additionally, to explore the role of the cis-regulatory elements in regulating the expression of SamDC gene in plants we comparatively analyzed the binding of rice nuclear proteins prepared from IR-29 and Nonabokra undergoing various stress treatments. The intensity of the complex formed was low and inducible in IR-29 in contrast to Nonabokra. Southwestern blot analysis helped in predicting the size of the trans-acting factors binding to these cis-elements. To our knowledge this is the first report on the comprehensive analysis of SamDC gene expression in rice and identification of the trans-acting factors regulating its expression.

Ontogeny of methionine utilization and splanchnic uptake in critically ill children

Science.gov (United States)

To determine the rates of methionine splanchnic uptake and utilization in critically ill pediatric patients, we used two kinetic models: the plasma methionine enrichment,and the "intracellular" homocysteine enrichment. Twenty-four patients, eight infants, eight children, and eight adolescents, were ...

Study of radiation effects on the senescence accelerated mouse (SAM), 1

International Nuclear Information System (INIS)

Kishikawa, Masao; Iseki, Masachika; Kondo, Hisayoshi

1989-01-01

The study of age-related changes in the central nervous system due to irradiation is being carried out in our laboratory. The senescence accelerated mouse (SAM P/1, male) was used for this investigation concerning the one-trial passive avoidance reaction. The experimental group of SAM P/1 was irradiated with 4 Gy at 8 weeks old, and passive avoidance reaction (PAR) was measured for 180 seconds as a learning task. At the age of 7 months, statistical analysis of PAR was conducted using the life time analysis method. The passive avoidance reaction of the irradiated group was more impaired than that of the control group. The results of this investigation suggested that the learning and/or memory disturbance of irradiated SAM P/1 is similar to the changes of more aged SAM P/1. (author)

Importance of methionine biosynthesis for Arabidopsis seed germination and seedling growth

NARCIS (Netherlands)

Gallardo, K.; Job, C.; Groot, S.P.C.; Puype, M.; Demol, H.; VandeKerckhove, J.; Job, D.

2002-01-01

Proteomics of Arabidopsis seeds revealed the differential accumulation during germination of two housekeeping enzymes. The first corresponded to methionine synthase that catalyses the last step in the plant methionine biosynthetic pathway. This protein was present at low level in dry mature seeds,

CareSam

DEFF Research Database (Denmark)

Liveng, Anne; Christensen, Jonas

2016-01-01

negative cultural perceptions of help-needing elderly and the people who support them in everyday life? In answering these questions and thereby reflecting on our own work process we apply a caring, a learning and a political perspective. Hereby the article wishes to formulate a methodological point...... to maintain immediately conflicting dimensions in this kind of work.......This article presents findings and discussions generated on the basis of the Danish-Swedish development project CareSam. The article will on the one hand focus on how work in groups consisting of representatives from different levels in the elderly care sector at one time served as learning spaces...

DZNep, inhibitor of S-adenosylhomocysteine hydrolase, down-regulates expression of SETDB1 H3K9me3 HMTase in human lung cancer cells.

Science.gov (United States)

Lee, Ju-Kyung; Kim, Keun-Cheol

2013-09-06

3-Deazaneplanocin A (DZNep), an epigenetic anticancer drug, leads to the indirect suppression of S-adenosyl methionine-dependent cellular methylations by inhibiting S-adenosyl homocystein (AdoHcy) hydrolase. Although it is well known that DZNep targets the degradation of EZH2 protein, H3K27me3 HMTase, there are still uncertainties about the regulation of other types of HMTases during cell death. In this study, we describe that SETDB1 gene expression was regulated by DZNep treatment in human lung cancer cells. We confirm that DZNep induced growth inhibition and increased the dead cell population of lung cancer cells. DZNep treatment affected histone methylations, including H3K27me3 and H3K9me3, but not H3K4me3. Reduced levels of H3K27me3 and H3K9me3 were related with the decreased EZH2 and SETDB1 proteins. Real time PCR analysis showed that SETDB1 gene expression was decreased by DZNep treatment, but no effect was observed for EZH2 gene expression. We cloned the promoter region of SETDB1 and SUV39H1 genes, and performed luciferase assays. The promoter activity of SETDB1 gene was down regulated by DZNep treatment, whereas no effect on SUV39H1 promoter activity was observed. In conclusion, we suggest that DZNep regulates not only on H3K27me3 HMTase EZH2, but also H3K9 HMTase SETDB1 gene expression at the transcription level, implicating that the mechanism of action of DZNep targets multiple HMTases during the death of lung cancer cells. Copyright © 2013 Elsevier Inc. All rights reserved.

Synthesis of high specific activity tritium labelled compounds

International Nuclear Information System (INIS)

Parent, P.

1986-01-01

Tritiated methyl iodide of high specific activity is synthetized by Fischer-Tropsch reaction of tritium with carbon monoxide, tritiated methanol obtained is reacted with hydriodic acid. It is used for the synthesis of S-adenosyl L-methionine 3 H-methyl and of diazepam 3 H-methyl derivatives. Synthesis of 3-PPP 3 H: (hydroxy-3 phenyl)-3N-n propyl [ 3 H-2.3] piperidine [ 3 H-2.3] with a specific activity of 4.25 T Bq/mM (115 Ci/mM) and of baclofene 3 H with a specific activity of 0.925 TBq (25 Ci/mM) are also described [fr

Preparation, crystallization and preliminary X-ray analysis of the methionine synthase (MetE) from Streptococcus mutans

Energy Technology Data Exchange (ETDEWEB)

Fu, Tian-Min; Zhang, Xiao-Yan; Li, Lan-Fen; Liang, Yu-He, E-mail: liangyh@pku.edu.cn; Su, Xiao-Dong [National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871 (China); Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing 100871 (China)

2006-10-01

Methionine synthase (MetE) from S. mutans was expressed, purified and crystallized. Diffraction data have been collected to 2.2 Å resolution. The Streptococcus mutans metE gene encodes methionine synthase (MetE), which catalyzes the direct transfer of a methyl group from methyltetrahydrofolate to homocysteine in the last step of methionine synthesis. metE was cloned into pET28a and the gene product was expressed at high levels in the Escherichia coli strain BL21 (DE3). MetE was purified to homogeneity using Ni{sup 2+}-chelating chromatography followed by size-exclusion chromatography. Crystals of the protein were obtained by the hanging-drop vapour-diffusion method and diffracted to 2.2 Å resolution. The crystal belongs to space group P2{sub 1}, with unit-cell parameters a = 52.85, b = 99.48, c = 77.88 Å, β = 94.55°.

iSAM: An iPhone Stealth Airborne Malware

OpenAIRE

Damopoulos , Dimitrios; Kambourakis , Georgios; Gritzalis , Stefanos

2011-01-01

Part 2: Malware, Information Flow and DoS Attacks; International audience; Modern and powerful mobile devices comprise an attractive target for any potential intruder or malicious code. The usual goal of an attack is to acquire users’ sensitive data or compromise the device so as to use it as a stepping stone (or bot) to unleash a number of attacks to other targets. In this paper, we focus on the popular iPhone device.We create a new stealth and airborne malware namely iSAM able to wirelessly...

Potensi Tinggalan Arkeologis di Kawasan Bandar Udara Sam Ratulangi Manado: Upaya Pelestarian, Pemanfaatan, dan Pengembangan bagi Masyarakat

Directory of Open Access Journals (Sweden)

Irfanuddin W. Marzuki

2016-08-01

Full Text Available The area of Sam Ratulangi airport’s Manado has archaeological heritage which has been know as it is closed for public. This research used descriptive method, using inductive reasoning. Meanwhile, the analysis method used morphologyl, technology, and contextual analysis. This research aimed to find out the potential of archaeological heritage in Sam Ratulangi airport area of Manado. In addition to its strategy of preservation the haritage included veilbox, bungker, and waruga. The preservation can be conducted by doing protection, development, and utilization. The preservation both physical and non physical protection. The effort for its development and utilization was conducted for the purpose of science, education, culture, and tourism. Kawasan Bandar Udara Sam Ratulangi Manado mempunyai potensi tinggalan arkeologis yang selama ini tidak diketahui masyarakat luas, dikarenakan letak tinggalan yang berada dalam kawasan tertutup untuk umum. Penelitian menggunakan metode deskriptif dengan penalaran induktif. Metode analisis menggunakan analisis morfologi, teknologi dan kontekstual. Tujuan penelitian untuk mengetahui potensi tinggalan arkeologis yang terdapat di kawasan Bandar Udara Sam Ratulangi dan strategi pelestariannya. Tinggalan arkeologis yang terdapat di kawasan Bandar Udara Sam Ratulangi meliputi veilbox, bungker, dan waruga. Upaya pelestarian dapat dilakukan dengan cara perlindungan, pengembangan dan pemanfaatan. Upaya perlindungan meliputi perlindungan secara fisik dan non fisik. Upaya pengembangan dan pemanfaatan dilakukan untuk kepentingan ilmu pengetahuan, pendidikan, kebudayaan dan pariwisata.

The SAMS: Smartphone Addiction Management System and verification.

Science.gov (United States)

Lee, Heyoung; Ahn, Heejune; Choi, Samwook; Choi, Wanbok

2014-01-01

While the popularity of smartphones has given enormous convenience to our lives, their pathological use has created a new mental health concern among the community. Hence, intensive research is being conducted on the etiology and treatment of the condition. However, the traditional clinical approach based surveys and interviews has serious limitations: health professionals cannot perform continual assessment and intervention for the affected group and the subjectivity of assessment is questionable. To cope with these limitations, a comprehensive ICT (Information and Communications Technology) system called SAMS (Smartphone Addiction Management System) is developed for objective assessment and intervention. The SAMS system consists of an Android smartphone application and a web application server. The SAMS client monitors the user's application usage together with GPS location and Internet access location, and transmits the data to the SAMS server. The SAMS server stores the usage data and performs key statistical data analysis and usage intervention according to the clinicians' decision. To verify the reliability and efficacy of the developed system, a comparison study with survey-based screening with the K-SAS (Korean Smartphone Addiction Scale) as well as self-field trials is performed. The comparison study is done using usage data from 14 users who are 19 to 50 year old adults that left at least 1 week usage logs and completed the survey questionnaires. The field trial fully verified the accuracy of the time, location, and Internet access information in the usage measurement and the reliability of the system operation over more than 2 weeks. The comparison study showed that daily use count has a strong correlation with K-SAS scores, whereas daily use times do not strongly correlate for potentially addicted users. The correlation coefficients of count and times with total K-SAS score are CC = 0.62 and CC =0.07, respectively, and the t-test analysis for the

Automated one-loop calculations with GoSam

International Nuclear Information System (INIS)

Cullen, Gavin; Greiner, Nicolas; Heinrich, Gudrun; Reiter, Thomas; Luisoni, Gionata; Mastrolia, Pierpaolo; Ossola, Giovanni; Tramontano, Francesco

2012-01-01

We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop. (orig.)

Automated One-Loop Calculations with GoSam

CERN Document Server

Cullen, Gavin; Heinrich, Gudrun; Luisoni, Gionata; Mastrolia, Pierpaolo; Ossola, Giovanni; Reiter, Thomas; Tramontano, Francesco

2012-01-01

We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop.

C-11 production with MC-50 cyclotron and synthesis of L-[11C-methyl] methionine

International Nuclear Information System (INIS)

Kim, Sang Wook; Hur, Min Goo; Yang, Seung Dae; Ahn, Soon Hyuk; Chun, Kweon Soo

2003-01-01

L-[ 11 C-methyl] methionine was prepared via no-carrier-added(nca) fast S-alkylation of L-homocysteine with [ 11 C]CH 3 I using solid support (Al 2 O 3 /KF)at room temperature in ethanol. The radiochemical yield of methylation was 90.2%. After reaction, no radiochemical impurity was detected but traces of L-homocysteine precursor were monitored by UV detector. The purification was archived by passing successively through a C 18 and alumina sep-pak. the radiochemical purity of L-[ 11 C-methyl] methionine was over 98% after purification and total elapsed time to prepare was 10min from [ 11 C]CH 3 I delivery

Teleconnection stationarity, variability and trends of the Southern Annular Mode (SAM) during the last millennium

Science.gov (United States)

Dätwyler, Christoph; Neukom, Raphael; Abram, Nerilie J.; Gallant, Ailie J. E.; Grosjean, Martin; Jacques-Coper, Martín; Karoly, David J.; Villalba, Ricardo

2017-11-01

The Southern Annular Mode (SAM) is the leading mode of atmospheric interannual variability in the Southern Hemisphere (SH) extra-tropics. Here, we assess the stationarity of SAM spatial correlations with instrumental and paleoclimate proxy data for the past millennium. The instrumental period shows that temporal non-stationarities in SAM teleconnections are not consistent across the SH land areas. This suggests that the influence of the SAM index is modulated by regional effects. However, within key-regions with good proxy data coverage (South America, Tasmania, New Zealand), teleconnections are mostly stationary over the instrumental period. Using different stationarity criteria for proxy record selection, we provide new austral summer and annual mean SAM index reconstructions over the last millennium. Our summer SAM reconstructions are very robust to changes in proxy record selection and the selection of the calibration period, particularly on the multi-decadal timescale. In contrast, the weaker performance and lower agreement in the annual mean SAM reconstructions point towards changing teleconnection patterns that may be particularly important outside the summer months. Our results clearly portend that the temporal stationarity of the proxy-climate relationships should be taken into account in the design of comprehensive regional and hemispherical climate reconstructions. The summer SAM reconstructions show no significant relationship to solar, greenhouse gas and volcanic forcing, with the exception of an extremely strong negative anomaly following the AD 1257 Samalas eruption. Furthermore, reconstructed pre-industrial summer SAM trends are very similar to trends obtained by model control simulations. We find that recent trends in the summer SAM lie outside the 5-95% range of pre-industrial natural variability.

SAMS: The synchronization and monitoring system for ATF [Advanced Toroidal Facility] data acquisition

International Nuclear Information System (INIS)

Greenwood, D.E.

1987-01-01

SAMS performs much of the synchronization of the distributed data acquisition system for the Advanced Toroidal Facility (ATF). SAMS is responsible for propagating shot information and managing te data system directories and logical names. This paper describes how SAMS communicates with other processes, both within the VAX cluster that supports most of the ATF data acquisition and on VAXes that are connected to the cluster via DECnet. 3 refs

Evolved Gas Analyses of Sedimentary Materials in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars (SAM) Instrument from Yellowknife Bay to the Stimson Formation

Science.gov (United States)

Sutter, B.; McAdam, A. C.; Rampe, E. B.; Ming, D. W.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Stern, J. C.; Eigenbrode, J. L.; Archer, P. D.

2016-01-01

The Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory rover has analyzed 10 samples from Gale Crater. All SAM evolved gas analyses have yielded a multitude of volatiles (e.g, H2O, SO2, H2S, CO2, CO, NO, O2, HC1). The objectives of this work are to 1) Characterize the evolved H2O, SO2, CO2, and O2 gas traces of sediments analyzed by SAM through sol 1178, 2) Constrain sediment mineralogy/composition based on SAM evolved gas analysis (SAM-EGA), and 3) Discuss the implications of these results releative to understanding the geochemical history of Gale Crater.

Alternative function for the mitochondrial SAM complex in biogenesis of alpha-helical TOM proteins.

Science.gov (United States)

Stojanovski, Diana; Guiard, Bernard; Kozjak-Pavlovic, Vera; Pfanner, Nikolaus; Meisinger, Chris

2007-12-03

The mitochondrial outer membrane contains two preprotein translocases: the general translocase of outer membrane (TOM) and the beta-barrel-specific sorting and assembly machinery (SAM). TOM functions as the central entry gate for nuclear-encoded proteins. The channel-forming Tom40 is a beta-barrel protein, whereas all Tom receptors and small Tom proteins are membrane anchored by a transmembrane alpha-helical segment in their N- or C-terminal portion. Synthesis of Tom precursors takes place in the cytosol, and their import occurs via preexisting TOM complexes. The precursor of Tom40 is then transferred to SAM for membrane insertion and assembly. Unexpectedly, we find that the biogenesis of alpha-helical Tom proteins with a membrane anchor in the C-terminal portion is SAM dependent. Each SAM protein is necessary for efficient membrane integration of the receptor Tom22, whereas assembly of the small Tom proteins depends on Sam37. Thus, the substrate specificity of SAM is not restricted to beta-barrel proteins but also includes the majority of alpha-helical Tom proteins.

Degradation of platinum based anticancer drugs by methionine: An EXAFS study

Energy Technology Data Exchange (ETDEWEB)

Provost, K; Bouvet-Muller, D; Michalowicz, A [ICMPE, UMR 7182 CNRS-Universite Paris 12, 94320 Thiais (France); Crauste-Manciet, S [Laboratoire de Pharmacie Galenique, Universite Paris Descartes, 75006 Paris (France); Olivi, L; Vlaic, G, E-mail: provost@univ-paris12.f [EXAFS Beamline, ELETTRA, Sincrotone Trieste, 34012 Basovizza, Trieste (Italy)

2009-11-15

We characterized the structures in solution of carboplatin and oxaliplatin degradation products in presence of a large excess of methionine (Met). The reaction of carboplatin leads to the formation of cis-Pt(Met){sub 2} while, in the case of oxaliplatin, methionine displaces only the oxalate ligand to form Pt(diaminocyclohexane)(Met).

A classification model of Hyperion image base on SAM combined decision tree

Science.gov (United States)

Wang, Zhenghai; Hu, Guangdao; Zhou, YongZhang; Liu, Xin

2009-10-01

Monitoring the Earth using imaging spectrometers has necessitated more accurate analyses and new applications to remote sensing. A very high dimensional input space requires an exponentially large amount of data to adequately and reliably represent the classes in that space. On the other hand, with increase in the input dimensionality the hypothesis space grows exponentially, which makes the classification performance highly unreliable. Traditional classification algorithms Classification of hyperspectral images is challenging. New algorithms have to be developed for hyperspectral data classification. The Spectral Angle Mapper (SAM) is a physically-based spectral classification that uses an ndimensional angle to match pixels to reference spectra. The algorithm determines the spectral similarity between two spectra by calculating the angle between the spectra, treating them as vectors in a space with dimensionality equal to the number of bands. The key and difficulty is that we should artificial defining the threshold of SAM. The classification precision depends on the rationality of the threshold of SAM. In order to resolve this problem, this paper proposes a new automatic classification model of remote sensing image using SAM combined with decision tree. It can automatic choose the appropriate threshold of SAM and improve the classify precision of SAM base on the analyze of field spectrum. The test area located in Heqing Yunnan was imaged by EO_1 Hyperion imaging spectrometer using 224 bands in visual and near infrared. The area included limestone areas, rock fields, soil and forests. The area was classified into four different vegetation and soil types. The results show that this method choose the appropriate threshold of SAM and eliminates the disturbance and influence of unwanted objects effectively, so as to improve the classification precision. Compared with the likelihood classification by field survey data, the classification precision of this model

Crystal Structures of the Helicobacter pylori MTAN Enzyme Reveal Specific Interactions between S-Adenosylhomocysteine and the 5'-Alkylthio Binding Subsite

Energy Technology Data Exchange (ETDEWEB)

Mishra, Vidhi [Univ. of Toledo, OH (United States); Ronning, Donald R. [Univ. of Toledo, OH (United States)

2012-11-13

The bacterial 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) enzyme is a multifunctional enzyme that catalyzes the hydrolysis of the N-ribosidic bond of at least four different adenosine-based metabolites: S-adenosylhomocysteine (SAH), 5'-methylthioadenosine (MTA), 5'-deoxyadenosine (5'-DOA), and 6-amino-6-deoxyfutalosine. These activities place the enzyme at the hub of seven fundamental bacterial metabolic pathways: S-adenosylmethionine (SAM) utilization, polyamine biosynthesis, the purine salvage pathway, the methionine salvage pathway, the SAM radical pathways, autoinducer-2 biosynthesis, and menaquinone biosynthesis. The last pathway makes MTAN essential for Helicobacter pylori viability. Although structures of various bacterial and plant MTANs have been described, the interactions between the homocysteine moiety of SAH and the 5'-alkylthiol binding site of MTAN have never been resolved. We have determined crystal structures of an inactive mutant form of H. pylori MTAN bound to MTA and SAH to 1.63 and 1.20 Å, respectively. The active form of MTAN was also crystallized in the presence of SAH, allowing the determination of the structure of a ternary enzyme–product complex resolved at 1.50 Å. These structures identify interactions between the homocysteine moiety and the 5'-alkylthiol binding site of the enzyme. This information can be leveraged for the development of species-specific MTAN inhibitors that prevent the growth of H. pylori.

Effects of sucrose on rFVIIa aggregation and methionine oxidation

DEFF Research Database (Denmark)

Soenderkaer, Susanne; Carpenter, John F; van de Weert, Marco

2004-01-01

The aim of this study was to characterize the effects of sucrose on the stability of recombinant factor VIIa (rFVIIa), with special emphasis on aggregation and methionine oxidation, as well as to investigate the impact of various environmental conditions on the rFVIIa conformation. The stability...... of rFVIIa was studied at pH 5. Aggregation was monitored using size exclusion high-performance liquid chromatography (SE-HPLC), whereas formation of methionine oxidation products was measured by reversed-phase high-performance liquid chromatography (RP-HPLC). Fourier transform infrared (FTIR...... the protein's surface, which shifts the protein molecular population away from expanded aggregation competent species and toward the compact native state, is thought to account for these observations. rFVIIa is sensitive to methionine oxidation; two mono-oxidized and one di-oxidized product were formed upon...

Quality Control Guidelines for SAM Biotoxin Methods

Science.gov (United States)

Learn more about quality control guidelines and recommendations for the analysis of samples using the pathogen methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Quality Control Guidelines for SAM Radiochemical Methods

Science.gov (United States)

Learn more about quality control guidelines and recommendations for the analysis of samples using the radiochemistry methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Quality Control Guidelines for SAM Pathogen Methods

Science.gov (United States)

Learn more about quality control guidelines and recommendations for the analysis of samples using the biotoxin methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Quality Control Guidelines for SAM Chemical Methods

Science.gov (United States)

Learn more about quality control guidelines and recommendations for the analysis of samples using the chemistry methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Non-Photolithographic Manufacturing Processes for Micro-Channels Functioned by Micro-Contact-Printed SAMs

Science.gov (United States)

Saigusa, Hiroki; Suga, Yasuo; Miki, Norihisa

In this paper we propose non-photolithographic fabrication processes of micro-fluid channels with patterned SAMs (Self-Assembled-Monolayers). SAMs with a thiol group are micro-contact printed on a patterned Au/Ti layer, which is vapor-deposited through a shadow mask. Ti is an adhesion layer. Subsequently, the micro-channels are formed by bonding surface-activated PDMS onto the silicon substrate via a silanol group, producing a SAMs-functioned bottom wall of the micro-channel. No photolithographic processes are necessary and thus, the proposed processes are very simple, quick and low cost. The micro-reactors can have various functions associated with the micro-contact-printed SAMs. We demonstrate successful manufacturing of micro-reactors with two types of SAMs. The micro-reactor with patterned AUT (11-amino-1-undecanethiol) successfully trapped nano-particles with a carboxylic acid group, indicating that micro-contact-printed SAMs remain active after the manufacturing processes of the micro-reactor. AUT -functioned micro-channels are applicable to bioassay and to immobilize proteins for DNA arrays. ODT (1-octadecanethiol) makes surfaces hydrophobic with the methyl terminal group. When water was introduced into the micro-reactor with ODT-patterned surfaces, water droplets remained only in the hydrophilic areas where ODT was not patterned. ODT -functioned micro-channels are applicable to fluid handling.

Ferulic acid depletion by cultured soybean seedlings under action of glucose and methionine

Directory of Open Access Journals (Sweden)

Herrig Vanessa

2000-01-01

Full Text Available Cultured soybean seedlings were used to investigate how glucose or methionine influenced depletion of ferulic acid. Three-day-old seedlings were grown in hydroponic solution containing ferulic acid plus glucose or methionine, and the level of the phenolic acid were monitored in the nutrient culture. The results showed that ferulic acid depletion was more rapid in the presence of those compounds. After 6 h, the increase caused by glucose (0.01 and 0.05 mM was more pronounced than methionine in the same concentrations. On the other hand, methionine (0.1 and 0.2 mM increased depletion more significantly than glucose. Results suggested that both compounds might to increase the allelopathic effects of ferulic acid in the seedlings.

Mechanism of oxidation of L-methionine by iron(III)-1,10 ...

Indian Academy of Sciences (India)

Unknown

Abstract. Kinetics and mechanism of oxidation of L-methionine by iron(III)–1,10- phenanthroline complex have been studied in perchloric acid medium. The reaction is first order each in iron(III) and methionine. Increase in [phenanthroline] increases the rate while increase in [HClO4] decreases it. While the reactive species ...

A practical and pyrogen-free preparation of 11C-L-methionine in a good manufacturing practice-compliant approach

Directory of Open Access Journals (Sweden)

Kang-Po Li

2017-01-01

Full Text Available Aims: 11C-L-methionine, an amino acid tracer used to delineate certain tumor tissues, has proven to be a prevailing nonfluorodeoxyglucose positron emission tomography (PET radiopharmaceutical. We intended to prepare 11C-L-methionine by following modified synthetic strategies at a rebuilt working area to meet the PET drug current good manufacturing practice (cGMP and Pharmaceutical Inspection Co-operation Scheme (PIC/S regulations. Furthermore, we overcame the problem of pyrogen cross-contamination using a cleaner and more efficient program. Material and Methods: The task of upgrading air filtration equipment was integrated with the set of Web-Based Building Automation system (WebCTRL®. 11C-L-methionine synthesis was carried out in accordance with redesigned methods to meet the requirements of PET drug cGMP. The product quality was tested by a series of quality control tests and was found to be satisfactory. Depyrogenation was carried out by three different methods with different flow rates and flushing durations. The results were examined through limulus amebocyte lysate clotting test. Results: The level of air cleanliness in each section meets the PIC/S GMP standards after the reconstructions. Moreover, after delicate modifications, the radiochemical yield of 11C-L-methionine was 36.20% ± 3.59% (based on 11C-CH3I, n = 7, which is about 10% higher than the average former yield. Besides, the used depyrogenation methods could wipe the bioburden off within 8 h. Conclusions: The modifications done not only offer a good production environment but also protect the products from contamination. The modified approaches in both 11C-L-methionine production and depyrogenation resulted in prominent progress in stability and efficiency as well.

Transfer RNA methylases in rat placenta

International Nuclear Information System (INIS)

Jagtiani, S.K.; Narurkar, L.M.; Narurkar, M.V.

1977-01-01

Presence of tRNA methylases (5-adenosylmethionine : tRNA methyltransferases) was demonstrated at various stages of gestation in rat placenta, the enzyme being 50-100% higher than that of adult rat liver during early gestation. Placental tRNA methylases were shown to differ from those of liver in the extent of methylation. Glycine methyltransferase (S-adenosylmethionine : glycine methyltransferase), a regulatory enzyme in adult rat liver, was absent in placenta throughout gestation. The placental tRNA methylases could be inhibited in vitro by semipurified glycine methyltransferase from adult rat liver. The high placental tRNA methylase activity was comparable with the inhibitor-free enzyme activity of the adult rat liver. S-adenosyl-[Me- 14 C]-methionine was used in the investigation. (author)

Is L-methionine a trigger factor for Alzheimer?s-like neurodegeneration?: Changes in A? oligomers, tau phosphorylation, synaptic proteins, Wnt signaling and behavioral impairment in wild-type mice

OpenAIRE

Tapia-Rojas, Cheril; Lindsay, Carolina B.; Montecinos-Oliva, Carla; Arrazola, Macarena S.; Retamales, Rocio M.; Bunout, Daniel; Hirsch, Sandra; Inestrosa, Nibaldo C.

2015-01-01

Background L-methionine, the principal sulfur-containing amino acid in proteins, plays critical roles in cell physiology as an antioxidant and in the breakdown of fats and heavy metals. Previous studies suggesting the use of L-methionine as a treatment for depression and other diseases indicate that it might also improve memory and propose a role in brain function. However, some evidence indicates that an excess of methionine can be harmful and can increase the risk of developing Type-2 diabe...

Biosynthesis of estragole and methyl-eugenol in sweet basil (Ocimum basilicum L). Developmental and chemotypic association of allylphenol O-methyltransferase activities.

Science.gov (United States)

Lewinsohn, E; Ziv-Raz, I; Dudai, N; Tadmor, Y; Lastochkin, E; Larkov, O; Chaimovitsh, D; Ravid, U; Putievsky, E; Pichersky, E; Shoham, Y

2000-12-07

Sweet basil (Ocimum basilicum L., Lamiaceae) is a common herb, used for culinary and medicinal purposes. The essential oils of different sweet basil chemotypes contain various proportions of the allyl phenol derivatives estragole (methyl chavicol), eugenol, and methyl eugenol, as well as the monoterpene alcohol linalool. To monitor the developmental regulation of estragole biosynthesis in sweet basil, an enzymatic assay for S-adenosyl-L-methionine (SAM):chavicol O-methyltransferase activity was developed. Young leaves display high levels of chavicol O-methyltransferase activity, but the activity was negligible in older leaves, indicating that the O-methylation of chavicol primarily occurs early during leaf development. The O-methyltransferase activities detected in different sweet basil genotypes differed in their substrate specificities towards the methyl acceptor substrate. In the high-estragole-containing chemotype R3, the O-methyltransferase activity was highly specific for chavicol, while eugenol was virtually not O-methylated. In contrast, chemotype 147/97, that contains equal levels of estragole and methyl eugenol, displayed O-methyltransferase activities that accepted both chavicol and eugenol as substrates, generating estragole and methyl eugenol, respectively. Chemotype SW that contains high levels of eugenol, but lacks both estragole and methyl eugenol, had apparently no allylphenol dependent O-methyltransferase activities. These results indicate the presence of at least two types of allylphenol-specific O-methyltransferase activities in sweet basil chemotypes, one highly specific for chavicol; and a different one that can accept eugenol as a substrate. The relative availability and substrate specificities of these O-methyltransferase activities biochemically rationalizes the variation in the composition of the essential oils of these chemotypes.

Synthesis and study of catalytic application of l-methionine protected gold nanoparticles

Science.gov (United States)

Raza, Akif; Javed, Safdar; Qureshi, Muhammad Zahid; khan, Muhammad Usman; Khan, Muhammad Saleem

2017-10-01

Gold nanoparticle is growing class of nanotechnology due to large number of uses. We synthesized stable l-methionine protected gold nanoparticles (AuNps) by in situ reduction of HAuCl4 using sodium borohydrate as reducing and l-methionine as stabilizing agent in an aqueous medium. Different parameters (pH, capping agent, precursor salt, and heating time) were optimized to see the effect on the size of particles. Double beam spectrophotometer was used to carry out the spectroscopic studies. It was observed that pH and concentration of reducing salt are deciding factors in controlling the size and morphology of AuNps. Scanning electron microscopy (SEM) verified the formation of AuNPs as predicted by UV-Vis spectra. The interaction of AuNPs with l-methionine was confirmed by Fourier Transform Infrared (FTIR). The reduction of 4-nitrophenol acted as standard of reaction to check the response of AuNps catalyst. Complete reduction of 4-nitrophenol was accomplished by AuNps sol in just 60 s. Fastest reduction rate was observed with smaller spherical particles. This study concluded that size and shape of AuNps can be monitored by controlling the pH, concentration of capping and reducing agent. It also provides an economical solution to aquatic environment in terms of time saving and use of small volume of catalytic solution for reduction of several other toxic organic pollutants.

Abnormal maternal biomarkers of homocysteine and methionine ...

African Journals Online (AJOL)

Rabah M. Shawky

2017-09-15

Sep 15, 2017 ... homocysteine and methionine metabolism are altered among non pregnant women who ..... groups as regards history of smoking, exposure to environmental ..... anomalies from 1950 to 1994: an international perspective.

Structural and functional characteristics of cGMP-dependent methionine oxidation in Arabidopsis thaliana proteins

KAUST Repository

Marondedze, Claudius

2013-01-05

Background: Increasing structural and biochemical evidence suggests that post-translational methionine oxidation of proteins is not just a result of cellular damage but may provide the cell with information on the cellular oxidative status. In addition, oxidation of methionine residues in key regulatory proteins, such as calmodulin, does influence cellular homeostasis. Previous findings also indicate that oxidation of methionine residues in signaling molecules may have a role in stress responses since these specific structural modifications can in turn change biological activities of proteins. Findings. Here we use tandem mass spectrometry-based proteomics to show that treatment of Arabidopsis thaliana cells with a non-oxidative signaling molecule, the cell-permeant second messenger analogue, 8-bromo-3,5-cyclic guanosine monophosphate (8-Br-cGMP), results in a time-dependent increase in the content of oxidised methionine residues. Interestingly, the group of proteins affected by cGMP-dependent methionine oxidation is functionally enriched for stress response proteins. Furthermore, we also noted distinct signatures in the frequency of amino acids flanking oxidised and un-oxidised methionine residues on both the C- and N-terminus. Conclusions: Given both a structural and functional bias in methionine oxidation events in response to a signaling molecule, we propose that these are indicative of a specific role of such post-translational modifications in the direct or indirect regulation of cellular responses. The mechanisms that determine the specificity of the modifications remain to be elucidated. 2013 Marondedze et al.; licensee BioMed Central Ltd.

[11C] Methionine as PET radiopharmaceutical produced at CDTN/CNEN

International Nuclear Information System (INIS)

Silveira, Marina B.; Ferreira, Soraya Z.; Carvalho, Tiago F.; Silva, Juliana B. da

2013-01-01

Carbon-11 ( 11 C) is an attractive radionuclide used in positron emission tomography (PET) since carbon is a ubiquitous element in biomolecules. Positron emitter-labeled amino acids are being widely used as indicators of tumor activity due to enhanced expression of amino acid transporter systems in cancer cells. L-[Methyl-( 11 C)] Methionine or [ 11 C]Methionine is being used in neuro-oncology and, unlike 2-[ 18 F]fluoro-2-deoxy-D-glucose ( 18 FDG), gives more contrast images and improves brain tumor diagnosis. The aim of this work was to develop the synthesis and quality control of [ 11 C]Methionine at the Radiopharmaceuticals Research and Production Facility (UPPR) of CDTN/CNEN. The synthesis of [ 11 C] Methionine was performed using two Sep-Pak tC18 plus cartridges one as solid support for the 11 C-methylation of the precursor L-homocysteine thiolactone hydrochloride and another for purification. The pH, radionuclidic identity and purity, residual solvents, radiochemical and chemical purity of the final product were evaluated as described on the European Pharmacopoeia 7.0 monograph. Total synthesis time was 18 minutes, the radiochemical yield was approximately 15% (non-decay corrected) and radiochemical purity was greater than 95%. [ 11 C]Methionine was successfully synthesized at CDTN using the described procedures and complied with quality requirements. Due to the rapid growth of oncologic PET scans in last decade, 11 C labelling holds great promises in the next few years with the application of other tracers beyond 18 FDG. This pioneering work of UPPR/CDTN represents a response to the demands of a growing nuclear medicine in the country focused on achieving better diagnostic imaging. (author)

Nuclear magnetic resonance studies of amino acids and proteins. Side-chain mobility of methionine in the crystalline amonio acid and in crystallne sperm whale (Physeter catodon) myoglobin

International Nuclear Information System (INIS)

Keniry, M.A.; Rothgeb, T.M.; Smith, R.L.; Gutowsky, H.S.; Oldfield, E.

1983-01-01

Deuterium ( 2 H) nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation times (T 1 ) were obtained of L-[epsilon- 2 H 3 ]methionine, L-[epsilon- 2 H 3 ]methionine in a D,L lattice, and [S-methyl- 2 H 3 ]methionine in the crystalline solid state, as a function of temperature, in addition to obtaining 2 H T 1 and line-width results as a function of temperature on [epsilon- 2 H 3 ]methionine-labeled sperm whale (Physeter catodon) myoglobins by using the method of magnetic ordering. Also recorded were 13 C cross-polarization ''magic-angle'' sample-spinning NMR spectra of [epsilon- 13 C]methionine-labeled crystalline cyanoferrimyoglobin (at 37.7 MHz, corresponding to a magnetic field strength of 3.52 T) and of the same protein in aqueous solution

Technical Note: Methionine, a precursor of methane in living plants

Science.gov (United States)

Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

2015-03-01

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued not only about their contribution to the global methane budget but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds to be identified. We made use of stable isotope techniques to verify the in vivo formation of methane, and, in order to identify the carbon precursor, 13C positionally labeled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labeled methionine clearly identified the sulfur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

Winning Attitude & Dedication to Physical Therapy Keep Sam Schmidt on Track

Science.gov (United States)

Bosley, Nikki Prevenslik

2006-01-01

This article relates how Sam Schmidt returned to living a productive life after an accident left him with spinal cord injury. Schmidt was a former Indy Racing League driver who founded Sam Schmidt Motorsports after his accident in 2000. Schmidt's car hit the wall as he exited turn two during a practice session at Walt Disney World Speedway in…

Metabolism of S-adenosylmethionine in rat hepatocytes: transfer of methyl group from S-adenosylmethionine by methyltransferase reactions

International Nuclear Information System (INIS)

Tsukada, K.; Abe, T.; Kuwahata, T.; Mitsui, K.

1985-01-01

Treatment of rats with a methionine diet leads not only to a marked increase of S-adenosylmethionine synthetase in liver, but also to the increase of glycine, guanidoacetate and betaine-homocysteine methyltransferases. The activity of tRNA methyltransferase decreased with the increased amounts of methionine in the diets. However, the activities of phospholipids and S-adenosylmethionine-homocysteine methyltransferases did not show any significant change. When hepatocarcinogenesis induced by 2-fluorenylacetamide progresses, the activities of glycine and guanidoacetate methyltransferases in rat liver decreased, and could not be detected in tumorous areas 8 months after treatment. The levels of S-adenosylmethionine in the liver also decreased to levels of one-fifth of control animals at 8 months. The uptake and metabolism of [methyl- 3 H]-methionine and -S-adenosylmethionine have been investigated by in vivo and isolated hepatocytes. The uptake of methionine and transfer of methyl group to phospholipid in the cells by methionine were remarkably higher than those by S-adenosylmethionine. These results indicate that phospholipids in hepatocytes accept methyl group from S-adenosylmethionine immediately, when it is synthesized from methionine, before mixing its pool in the cells. 39 references, 1 figure, 2 tables

Technoeconomic Modeling of Battery Energy Storage in SAM

Energy Technology Data Exchange (ETDEWEB)

DiOrio, Nicholas [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dobos, Aron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Janzou, Steven [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nelson, Austin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lundstrom, Blake [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-09-01

Detailed comprehensive lead-acid and lithium-ion battery models have been integrated with photovoltaic models in an effort to allow System Advisor Model (SAM) to offer the ability to predict the performance and economic benefit of behind the meter storage. In a system with storage, excess PV energy can be saved until later in the day when PV production has fallen, or until times of peak demand when it is more valuable. Complex dispatch strategies can be developed to leverage storage to reduce energy consumption or power demand based on the utility rate structure. This document describes the details of the battery performance and economic models in SAM.

Experimental and computational investigation of graphene/SAMs/n-Si Schottky diodes

Science.gov (United States)

Aydin, H.; Bacaksiz, C.; Yagmurcukardes, N.; Karakaya, C.; Mermer, O.; Can, M.; Senger, R. T.; Sahin, H.; Selamet, Y.

2018-01-01

We have investigated the effect of two different self-assembled monolayers (SAMs) on electrical characteristics of bilayer graphene (BLG)/n-Si Schottky diodes. Novel 4″bis(diphenylamino)-1, 1‧:3″-terphenyl-5‧ carboxylic acids (TPA) and 4,4-di-9H-carbazol-9-yl-1,1‧:3‧1‧-terphenyl-5‧ carboxylic acid (CAR) aromatic SAMs have been used to modify n-Si surfaces. Cyclic voltammetry (CV) and Kelvin probe force microscopy (KPFM) results have been evaluated to verify the modification of n-Si surface. The current-voltage (I-V) characteristics of bare and SAMs modified devices show rectification behaviour verifying a Schottky junction at the interface. The ideality factors (n) from ln(I)-V dependences were determined as 2.13, 1.96 and 2.07 for BLG/n-Si, BLG/TPA/n-Si and BLG/CAR/n-Si Schottky diodes, respectively. In addition, Schottky barrier height (SBH) and series resistance (Rs) of SAMs modified diodes were decreased compared to bare diode due to the formation of a compatible interface between graphene and Si as well as π-π interaction between aromatic SAMs and graphene. The CAR-based device exhibits better diode characteristic compared to the TPA-based device. Computational simulations show that the BLG/CAR system exhibits smaller energy-level-differences than the BLG/TPA, which supports the experimental findings of a lower Schottky barrier and series resistance in BLG/CAR diode.

Mapping of sulfur metabolic pathway by LC Orbitrap mass spectrometry

International Nuclear Information System (INIS)

Rao Yulan; McCooeye, Margaret; Mester, Zoltán

2012-01-01

Highlights: ► LCMS method for the determination of free, oxidized and protein bound thiols in yeast was developed. ► In freshly harvested yeast, most of the thiols were in the reduced forms. ► The stress response of yeast to H 2 O 2 , Cd and As was studied via changes in the thiol profiles. - Abstract: For the first time a liquid chromatography method with high resolution mass spectrometric detection has been developed for the simultaneous determination all key metabolites of the sulfur pathway in yeast, including all thiolic (cysteine (Cys), homocysteine (HCys), glutathione (GSH), cysteinyl-glycine (Cys-Gly), γ-glutamyl-cysteine (Glu-Cys)) and non-thiolic compounds (methionine (Met), s-adenosyl-methionine (AdoMet), s-adenosyl-homocysteine (AdoHcy), and cystathionine (Cysta)). The developed assay also permits the speciation and selective determination of reduced, oxidized and protein bound fractions of all of the five thiols. Iodoacetic acid (IAA) was chosen as the derivatizing reagent. Thiols were extracted from sub-mg quantities of yeast using hot 75% ethanol. The detection limits were in the range of 1–12 nmol L −1 for standard solution (high femotomole, absolute), except AdoMet (116 nmol L −1 ), which was unstable. In freshly harvested yeast, most of the thiols were in the reduced forms and low levels of protein-bound GSH and Glu-Cys were found. In a selenium enriched yeast, the thiols were mainly in the oxidized forms, and a significant amount of protein-bound Cys, HCys, GSH, Cys-Gly and Glu-Cys were found. The method was also applied to the metabolic study of the adaptive response of Saccharomyces cerevisiae to hydrogen peroxide, cadmium, and arsenite, and the change in concentration of thiols in the sulfur pathway was monitored over a period of 4 h.

Mapping of sulfur metabolic pathway by LC Orbitrap mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Rao Yulan [Institute for National Measurement Standard, National Research Council Canada, Ottawa, Ontario K1A 0R6 (Canada); Department of Forensic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032 (China); McCooeye, Margaret [Institute for National Measurement Standard, National Research Council Canada, Ottawa, Ontario K1A 0R6 (Canada); Mester, Zoltan, E-mail: zoltan.mester@nrc.ca [Institute for National Measurement Standard, National Research Council Canada, Ottawa, Ontario K1A 0R6 (Canada)

2012-04-06

Highlights: Black-Right-Pointing-Pointer LCMS method for the determination of free, oxidized and protein bound thiols in yeast was developed. Black-Right-Pointing-Pointer In freshly harvested yeast, most of the thiols were in the reduced forms. Black-Right-Pointing-Pointer The stress response of yeast to H{sub 2}O{sub 2}, Cd and As was studied via changes in the thiol profiles. - Abstract: For the first time a liquid chromatography method with high resolution mass spectrometric detection has been developed for the simultaneous determination all key metabolites of the sulfur pathway in yeast, including all thiolic (cysteine (Cys), homocysteine (HCys), glutathione (GSH), cysteinyl-glycine (Cys-Gly), {gamma}-glutamyl-cysteine (Glu-Cys)) and non-thiolic compounds (methionine (Met), s-adenosyl-methionine (AdoMet), s-adenosyl-homocysteine (AdoHcy), and cystathionine (Cysta)). The developed assay also permits the speciation and selective determination of reduced, oxidized and protein bound fractions of all of the five thiols. Iodoacetic acid (IAA) was chosen as the derivatizing reagent. Thiols were extracted from sub-mg quantities of yeast using hot 75% ethanol. The detection limits were in the range of 1-12 nmol L{sup -1} for standard solution (high femotomole, absolute), except AdoMet (116 nmol L{sup -1}), which was unstable. In freshly harvested yeast, most of the thiols were in the reduced forms and low levels of protein-bound GSH and Glu-Cys were found. In a selenium enriched yeast, the thiols were mainly in the oxidized forms, and a significant amount of protein-bound Cys, HCys, GSH, Cys-Gly and Glu-Cys were found. The method was also applied to the metabolic study of the adaptive response of Saccharomyces cerevisiae to hydrogen peroxide, cadmium, and arsenite, and the change in concentration of thiols in the sulfur pathway was monitored over a period of 4 h.

Reactions Involving Calcium and Magnesium Sulfates as Potential Sources of Sulfur Dioxide During MSL SAM Evolved Gas Analyses

Science.gov (United States)

McAdam, A. C.; Knudson, C. A.; Sutter, B.; Franz, H. B.; Archer, P. D., Jr.; Eigenbrode, J. L.; Ming, D. W.; Morris, R. V.; Hurowitz, J. A.; Mahaffy, P. R.;

Methionine supplementation influences melanin-based plumage colouration in Eurasian kestrel, Falco tinnunculus, nestlings.

Science.gov (United States)

Parejo, Deseada; Silva, Nadia

2009-11-01

The extent to which the expression of melanin-based plumage colouration in birds is genetically or environmentally determined is controversial. Here, we performed a between-nest design supplementation with either the sulphur amino acid dl-methionine or with water to investigate the importance of the non-genetic component of melanin-based plumage colouration in the Eurasian kestrel, Falco tinnunculus. Methionine affects growth and immunity, thus we aimed to modify nestling growth and immunity before feather development. Then, we measured the effect of the experiment on colouration of two melanin-based plumage patches of nestling kestrels. We found that methionine slowed down nestling growth through treatment administration and that nestlings compensated by speeding up their growth later. We did not find any effects of methionine on nestling immunity (i.e. lymphocyte counts, natural antibody levels or complement-mediated immunity). Effects on growth seemed to be mirrored by changes in nestling colouration in the two sexes: methionine-nestlings showed less intense brown plumage on their backs compared with control nestlings. These results provide support for a non-genetic determination of a melanin-based plumage patch in the two sexes of nestling kestrels.

CONCENTRATION-DEPENDENT LINKAGE OF DIETARY METHIONINE RESTRICTION TO THE COMPONENTS OF ITS METABOLIC PHENOTYPE

OpenAIRE

Forney, Laura A.; Wanders, Desiree; Stone, Kirsten P.; Pierse, Alicia; Gettys, Thomas W.

2017-01-01

Objective Restricting dietary methionine to 0.17% produces a series of physiological responses through coordinated transcriptional effects in liver and adipose tissue. The goal of the present work was to determine the threshold concentrations above and below 0.17% at which the beneficial responses to 0.17% dietary methionine are preserved. Methods Diets were formulated to restrict methionine to different degrees, followed by evaluation of the transcriptional and physiological responses to the...

Sam Wagstaffi unustatud kired / Ahto Külvet

Index Scriptorium Estoniae

Külvet, Ahto

2008-01-01

Dokumentaalfilm "Black, White & Gray: Sam Wagstaff and Robert Mapplethorpe" : autor ja režissöör James Crump : Ameerika Ühendriigid 2007. Filmi näidati filminädala "Art in America" raames Tallinnas

Detection of Organics at Mars: How Wet Chemistry Onboard SAM Helps

Science.gov (United States)

Buch, A.; Freissinet, Caroline; Szopa, C.; Glavin, D.; Coll, P.; Cabane, M.; Eigenbrode, J.; Navarro-Gonzalez, R.; Coscia, D.; Teinturier, S.;

[11C] Methionine as PET radiopharmaceutical produced at CDTN/CNEN

Energy Technology Data Exchange (ETDEWEB)

Silveira, Marina B.; Ferreira, Soraya Z.; Carvalho, Tiago F.; Silva, Juliana B. da, E-mail: mbs@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Unidade de Pesquisa e Producao de Radiofarmacos

2013-07-01

Carbon-11 ({sup 11}C) is an attractive radionuclide used in positron emission tomography (PET) since carbon is a ubiquitous element in biomolecules. Positron emitter-labeled amino acids are being widely used as indicators of tumor activity due to enhanced expression of amino acid transporter systems in cancer cells. L-[Methyl-({sup 11}C)] Methionine or [{sup 11}C]Methionine is being used in neuro-oncology and, unlike 2-[{sup 18}F]fluoro-2-deoxy-D-glucose ({sup 18}FDG), gives more contrast images and improves brain tumor diagnosis. The aim of this work was to develop the synthesis and quality control of [{sup 11}C]Methionine at the Radiopharmaceuticals Research and Production Facility (UPPR) of CDTN/CNEN. The synthesis of [{sup 11}C] Methionine was performed using two Sep-Pak tC18 plus cartridges one as solid support for the {sup 11}C-methylation of the precursor L-homocysteine thiolactone hydrochloride and another for purification. The pH, radionuclidic identity and purity, residual solvents, radiochemical and chemical purity of the final product were evaluated as described on the European Pharmacopoeia 7.0 monograph. Total synthesis time was 18 minutes, the radiochemical yield was approximately 15% (non-decay corrected) and radiochemical purity was greater than 95%. [{sup 11}C]Methionine was successfully synthesized at CDTN using the described procedures and complied with quality requirements. Due to the rapid growth of oncologic PET scans in last decade, {sup 11}C labelling holds great promises in the next few years with the application of other tracers beyond {sup 18}FDG. This pioneering work of UPPR/CDTN represents a response to the demands of a growing nuclear medicine in the country focused on achieving better diagnostic imaging. (author)

Electronic patient self-assessment and management (SAM): a novel framework for cancer survivorship.

Science.gov (United States)

Vickers, Andrew J; Salz, Talya; Basch, Ethan; Cooperberg, Matthew R; Carroll, Peter R; Tighe, Foss; Eastham, James; Rosen, Raymond C

2010-06-17

We propose a novel framework for management of cancer survivorship: electronic patient Self-Assessment and Management (SAM). SAM is a framework for transfer of information to and from patients in such a way as to increase both the patient's and the health care provider's understanding of the patient's progress, and to help ensure that patient care follows best practice. Patients who participate in the SAM system are contacted by email at regular intervals and asked to complete validated questionnaires online. Patient responses on these questionnaires are then analyzed in order to provide patients with real-time, online information about their progress and to provide them with tailored and standardized medical advice. Patient-level data from the questionnaires are ported in real time to the patient's health care provider to be uploaded to clinic notes. An initial version of SAM has been developed at Memorial Sloan-Kettering Cancer Center (MSKCC) and the University of California, San Francisco (UCSF) for aiding the clinical management of patients after surgery for prostate cancer. Pilot testing at MSKCC and UCSF suggests that implementation of SAM systems are feasible, with no major problems with compliance (> 70% response rate) or security. SAM is a conceptually simple framework for passing information to and from patients in such a way as to increase both the patient's and the health care provider's understanding of the patient's progress, and to help ensure that patient care follows best practice.

Electronic patient self-assessment and management (SAM: a novel framework for cancer survivorship

Directory of Open Access Journals (Sweden)

Tighe Foss

2010-06-01

Full Text Available Abstract Background We propose a novel framework for management of cancer survivorship: electronic patient Self-Assessment and Management (SAM. SAM is a framework for transfer of information to and from patients in such a way as to increase both the patient's and the health care provider's understanding of the patient's progress, and to help ensure that patient care follows best practice. Methods Patients who participate in the SAM system are contacted by email at regular intervals and asked to complete validated questionnaires online. Patient responses on these questionnaires are then analyzed in order to provide patients with real-time, online information about their progress and to provide them with tailored and standardized medical advice. Patient-level data from the questionnaires are ported in real time to the patient's health care provider to be uploaded to clinic notes. An initial version of SAM has been developed at Memorial Sloan-Kettering Cancer Center (MSKCC and the University of California, San Francisco (UCSF for aiding the clinical management of patients after surgery for prostate cancer. Results Pilot testing at MSKCC and UCSF suggests that implementation of SAM systems are feasible, with no major problems with compliance (> 70% response rate or security. Conclusion SAM is a conceptually simple framework for passing information to and from patients in such a way as to increase both the patient's and the health care provider's understanding of the patient's progress, and to help ensure that patient care follows best practice.

Celiac Disease in Children with Severe Acute Malnutrition (SAM): A Hospital Based Study.

Science.gov (United States)

Beniwal, Neetu; Ameta, Gaurav; Chahar, Chandra Kumar

2017-05-01

To evaluate the prevalence and clinical features of Celiac disease among children with severe acute malnutrition (SAM). This prospective observational study was conducted in PBM Children Hospital, Bikaner from July 2012 through December 2013. All consecutively admitted children with SAM were recruited. All subjects were screened for Celiac disease by serological test for IgA-anti tissue Transglutaminase (IgA tTG) antibodies. All seropositive children underwent upper gastrointestinal endoscopy for small bowel biopsy for the confirmation. Clinical features of patients with and without celiac disease were compared. The sero-prevalence (IgA tTg positivity) of Celiac disease was found to be 15.38% while prevalence of biopsy confirmed Celiac disease was 14.42% among SAM children. Abdominal distension, diarrhea, anorexia, constipation, pain in abdomen, vitamin deficiencies, edema, clubbing and mouth ulcers were more common in patients of Celiac disease compared to patients without Celiac disease but the difference was statistically significant only for abdominal distension and pain abdomen. There is a high prevalence of Celiac disease in SAM. Screening for Celiac disease (especially in presence of pain abdomen and abdominal distension) should be an essential part of work-up in all children with SAM.

Influence of protein level and supplemental methionine in practical rations for young endangered masked bobwhite quail

Science.gov (United States)

Serafin, J.A.

1982-01-01

A study was conducted to examine the protein requirement of young endangered masked Bobwhite quail (Colinus virginianus ridgwayi). Five practical starting rations containing 24 to 32% protein were fed alone and supplemented with methionine for 5 weeks. Supplemental methionine significantly improved growth of quail fed diets containing 24 and 26% protein. Increasing the protein level improved growth of quail fed unsupplemented diets but did not do so when diets contained supplemental methionine. A methionine-supplemented ration containing 24% protein appeared adequate for supporting rapid growth of masked Bobwhite quail.

Utilization of supplemental methionine sources by primary cultures of chick hepatocytes

International Nuclear Information System (INIS)

Dibner, J.J.

1983-01-01

Utilization of 2-hydroxy-4-(methylthio) butanoic acid (HMB) as a substrate for protein synthesis was studied by using primary cultures of chick liver cells. Cultures were prepared by enzymatic dissociation of livers from week old Hubbard broiler chicks and were maintained for 4 days under nonproliferative conditions. Hepatocyte differentiation was verified by using dexamethasone induction of tyrosine aminotransferase activity. Conversion of [14C]HMB to L-methionine was shown by chromatographic analysis of hepatocyte protein hydrolysate and incorporation into protein was proven by cycloheximide inhibition of synthesis. When incorporation of HMB was compared to that of DL-methionine (DLM) equimolar quantities of the two sources were found in liver cell protein. These results support, at a cellular level, the conclusion that HMB and DLM are biochemically equivalent sources of methionine for protein synthesis

Niedualna uważność a stan samādhi w kontekście badań neurofenomenologicznych

Directory of Open Access Journals (Sweden)

Piotr PŁANETA

2016-12-01

Full Text Available The aim of this paper is to compare various meditative states, such as Buddhist dhyāna‑s, yogic nirbīja samādhi and nondual awareness (Tib. gñis‑med. The primary source texts I refere to are Yogasūtras of Patañjali, Ānāpānasmṛtisūtra (MN 118, Samādhisūtra (AN 4.41, The Tibetan Yogas of Dream and Sleep. I also discuss some relevant claims of contemporary empirical studies. First, I define the key terms used in Eastern meditation studies as well as in neurophenomenology, a contemporary method applied to examining the meditative states of mind, such as samādhi, dhyāna, and śamatha. Inspired by Shinzen Young, I distinguish three groups of meditative states that might be identified with nondual awareness. These three groups are: (1 the second, the third and fourth Buddhist dhyāna being equivalent to nirvicāra samādhi and nirānanda samādhi in the classical Indian yoga; (2 nirbīja samādhi and (3 nondual awareness, typical to the Mahayāna contemplative traditions. I explain why we can recognize each of the above states as nondual awareness and how they differ from each other. Then, I make a comparison between meditation practice explained in Ānāpānasmṛtisūtra and nondual awareness presented in the Tibetan Buddhism. Besides, I discuss the above kinds of mental states in terms of recent neurophenomenological findings. While doing so, I am trying to demonstrate that our understanding of meditation can benefit from the empirical studies which help us to objectify this kind of subjective experience, to some degree, if they are given an adequate place in our study.

Absorption of l-methionine from the human small intestine

Science.gov (United States)

Schedl, Harold P.; Pierce, Charles E.; Rider, Alan; Clifton, James A.

1968-01-01

Absorption of L-methionine was measured in all parts of the human small intestine using transintestinal intubation and perfusion. In four normal subjects, adsorption was higher in the proximal than in the distal intestine. In two patients with nontropical sprue in relapse, there was a proximal zone of low absorption with higher absorption distally. In all parts of the small intestine, absorption showed rate-limiting kinetics as methionine concentration was increased. In normal subjects, the proximal Km (Michaelis constant) was more than 3 times higher than the distal, which suggests a difference in transport mechanisms between the two segments. PMID:12066784

Tissue methionine cycle activity and homocysteine metabolism in female rats: impact of dietary methionine and folate plus choline

NARCIS (Netherlands)

Wilson, F.A.; Borne, van den J.J.G.C.; Calder, A.G.; O'Kennedy, N.; Holtrop, G.; Rees, W.D.; Lobley, G.E.

2009-01-01

Impaired transfer of methyl groups via the methionine cycle leads to plasma hyperhomocysteinemia. The tissue sources of plasma homocysteine in vivo have not been quantified nor whether hyperhomocysteinemia is due to increased entry or decreased removal. These issues were addressed in female rats

Multiple endmember spectral-angle-mapper (SAM) analysis improves discrimination of Savanna tree species

CSIR Research Space (South Africa)

Cho, Moses A

2009-08-01

Full Text Available of this paper was to evaluate the classification performance of a multiple-endmember spectral angle mapper (SAM) classification approach in discriminating seven common African savanna tree species and to compare the results with the traditional SAM classifier...

Independent and additive effects of glutamic acid and methionine on yeast longevity.

Science.gov (United States)

Wu, Ziyun; Song, Lixia; Liu, Shao Quan; Huang, Dejian

2013-01-01

It is established that glucose restriction extends yeast chronological and replicative lifespan, but little is known about the influence of amino acids on yeast lifespan, although some amino acids were reported to delay aging in rodents. Here we show that amino acid composition greatly alters yeast chronological lifespan. We found that non-essential amino acids (to yeast) methionine and glutamic acid had the most significant impact on yeast chronological lifespan extension, restriction of methionine and/or increase of glutamic acid led to longevity that was not the result of low acetic acid production and acidification in aging media. Remarkably, low methionine, high glutamic acid and glucose restriction additively and independently extended yeast lifespan, which could not be further extended by buffering the medium (pH 6.0). Our preliminary findings using yeasts with gene deletion demonstrate that glutamic acid addition, methionine and glucose restriction prompt yeast longevity through distinct mechanisms. This study may help to fill a gap in yeast model for the fast developing view that nutrient balance is a critical factor to extend lifespan.

GoSam. A program for automated one-loop calculations

Energy Technology Data Exchange (ETDEWEB)

Cullen, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Greiner, N.; Heinrich, G.; Reiter, T. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, G. [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, P. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, G. [City Univ. of New York, NY (United States). New York City College of Technology; Tramontano, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

2011-11-15

The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples. (orig.)

GoSam. A program for automated one-loop calculations

International Nuclear Information System (INIS)

Cullen, G.; Greiner, N.; Heinrich, G.; Reiter, T.; Luisoni, G.

2011-11-01

The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples. (orig.)

GoSam: A program for automated one-loop calculations

International Nuclear Information System (INIS)

Cullen, G; Greiner, N; Heinrich, G; Mastrolia, P; Reiter, T; Luisoni, G; Ossola, G; Tramontano, F

2012-01-01

The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples.

General Quality Control (QC) Guidelines for SAM Methods

Science.gov (United States)

Learn more about quality control guidelines and recommendations for the analysis of samples using the methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Feed efficiency of diets with different energy and protein concentrations supplemented with methionine in laying quails

Science.gov (United States)

Ratriyanto, A.; Indreswari, R.; Nuhriawangsa, A. M. P.; Purwanti, E.

2018-03-01

The study was conducted to evaluate the feed efficiency of quail diets containing different concentrations of metabolizable energy (ME) and crude protein (CP) with constant ratio and supplemented with methionine. Four hundred laying quails (Coturnix coturnix japonica) were randomly assigned to four experimental diets in a 2×2 factorial arrangement. Each dietary treatment used 5 replicates of 20 quails. Two basal diets were formulated to contain 2,800 kcal kg-1 ME and 18.7% CP (High ME-CP) and 2,600 kcal kg-1 ME and 17.3% CP (Low ME-CP). Each basal diet was supplemented with 0 and 0.12% methionine. The High ME-CP diets generated lower feed consumption but higher egg mass and feed efficiency (Pprotein efficiency ratio (PHigh ME-CP supplemented with methionine resulted the highest feed efficiency followed by the Low ME-CP supplemented with methionine, while both High ME-CP and Low ME-CP without methionine supplementation resulted the lowest feed efficiency (PHigh ME-CP supplemented with 0.12% methionine provided benefit to improve the feed efficiency in laying quails.

Individual radiation response of parotid glands investigated by dynamic 11C-methionine PET

International Nuclear Information System (INIS)

Buus, Simon; Grau, Cai; Munk, Ole Lajord; Rodell, Anders; Jensen, Kenneth; Mouridsen, Kim; Keiding, Susanne

2006-01-01

Background and Purpose: Previously, we showed that the net metabolic clearance of 11 C-methionine of the parotid gland, K, calculated from dynamic 11 C-methionine PET, can be used as a measure of parotid gland function. The aim of this study was to investigate by dynamic 11 C-methionine PET the individual radiation dose response relationship of parotid glands in head and neck cancer patients. Patients and methods: Twelve head and neck cancer patients were examined by dynamic 11 C-methionine PET after radiotherapy. Parametric images of K were generated, co-registered and compared voxel-by-voxel with the 3D radiation dose plan within the parotid gland to assess the individual radiation dose-function relationship. Results: In each patient, voxel-values of K decreased with increasing radiation dose. Population based analysis showed a sigmoid dose response relationship of parotid gland, from which we estimated a threshold radiation dose of 16 Gy and a mean TD 5 of 30 Gy. TD 5 ranged from 7 to 50 Gy in the group of patients. Conclusions: Individual radiation dose response of parotid glands can be measured by dynamic 11 C-methionine PET. The dose response analysis revealed a sigmoid relationship, a threshold radiation dose of 16 Gy, and a mean TD 5 of 30 Gy

The Porter-Whitesides Discrepancy: Revisiting Odd-Even Effects in Wetting Properties of n-Alkanethiolate SAMs

Directory of Open Access Journals (Sweden)

Zhengjia Wang

2015-12-01

Full Text Available This review discusses the Porter-Whitesides discrepancy in wetting properties of n-alkanethiolate self-assembled monolayers (SAMs. About 25 years ago, Whitesides and coworker failed to observe any odd-even effect in wetting, however, Porter and his coworker did, albeit in select cases. Most previous studies agreed with Whitesides’ results, suggesting the absence of the odd-even effect in hydrophobicity of n-alkanethiolate SAMs. Recent reports have, however, found the odd-even effect in hydrophobicity of n-alkanethiolate SAMs on smooth substrates, indicating that hydrophobicity, and analogous interfacial properties, of n-alkanethiolate SAMs significantly depends on the properties of substrate. Unfortunately, the Whitesides and Porter papers do not report on the quality of the surfaces used. Based on recent work, we inferred that the original discrepancy between Whitesides and Porter can be attributed to the quality of the surface. Odd-even effect of SAMs in charge transport, capacitance, friction, and SAM structure are also discussed in this review to inform the general discussion. The discrepancy between Porter's group and Whitesides’ group could be due to surface roughness, morphology, oxidation, and adventitious contaminants.

Constitutive expression of feedback-insensitive cystathionine γ-synthase increases methionine levels in soybean leaves and seeds

Institute of Scientific and Technical Information of China (English)

YU Yang; HOU Wen-sheng; YaeI Hacham; SUN Shi; WU Cun-xiang; Ifat Matityahu; SONG Shikui; RacheI Amir; HAN Tian-fu

2018-01-01

Soybean (Glycine max (L.) Merr.) is a major crop that provides plant-origin protein and oil for humans and livestock. Although the soybean vegetative tissues and seeds provide a major source of high-quality protein, they suffer from low concentration of an essential sulfur-containing amino acid, methionine, which significantly limits their nutritional quality. The level of methionine is mainly controlled by the first unique enzyme of methionine synthesis, cystathione γ-synthase (CGS). Aiming to elevate methionine level in vegetative tissues and seeds, we constitutively over-expressed a feedback-insensitive Arabidopsis CGS (AtD-CGS) in soybean cultivars, Zigongdongdou (ZD) and Jilinxiaoli 1 (JX). The levels of soluble methionine increased remarkably in leaves of transgenic soybeans compared to wild-type plants (6.6- and 7.3-fold in two transgenic ZD lines, and 3.7-fold in one transgenic JX line). Furthermore, the total methionine contents were significantly increased in seeds of the transgenic ZD lines (1.5- to 4.8-fold increase) and the transgenic JX lines (1.3- to 2.3-fold increase) than in the wild type. The protein contents of the transgenic soybean seeds were significantly elevated compared to the wild type, suggesting that the scarcity of methionine in soybeans may limit protein accumulation in soybean seeds. The increased protein content did not alter the profile of major storage proteins in the seeds. Generally, this study provides a promising strategy to increase the levels of methionine and protein in soybean through the breeding programs.

Choline and methionine differentially alter methyl carbon metabolism in bovine neonatal hepatocytes.

Science.gov (United States)

Chandler, Tawny L; White, Heather M

2017-01-01

Intersections in hepatic methyl group metabolism pathways highlights potential competition or compensation of methyl donors. The objective of this experiment was to examine the expression of genes related to methyl group transfer and lipid metabolism in response to increasing concentrations of choline chloride (CC) and DL-methionine (DLM) in primary neonatal hepatocytes that were or were not exposed to fatty acids (FA). Primary hepatocytes isolated from 4 neonatal Holstein calves were maintained as monolayer cultures for 24 h before treatment with CC (61, 128, 2028, and 4528 μmol/L) and DLM (16, 30, 100, 300 μmol/L), with or without a 1 mmol/L FA cocktail in a factorial arrangement. After 24 h of treatment, media was collected for quantification of reactive oxygen species (ROS) and very low-density lipoprotein (VLDL), and cell lysates were collected for quantification of gene expression. No interactions were detected between CC, DLM, or FA. Both CC and DLM decreased the expression of methionine adenosyltransferase 1A (MAT1A). Increasing CC did not alter betaine-homocysteine S-methyltranferase (BHMT) but did increase 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) and methylenetetrahydrofolate reductase (MTHFR) expression. Increasing DLM decreased expression of BHMT and MTR, but did not affect MTHFR. Expression of both phosphatidylethanolamine N-methyltransferase (PEMT) and microsomal triglyceride transfer protein (MTTP) were decreased by increasing CC and DLM, while carnitine palmitoyltransferase 1A (CPT1A) was unaffected by either. Treatment with FA decreased the expression of MAT1A, MTR, MTHFR and tended to decrease PEMT but did not affect BHMT and MTTP. Treatment with FA increased CPT1A expression. Increasing CC increased secretion of VLDL and decreased the accumulation of ROS in media. Within neonatal bovine hepatocytes, choline and methionine differentially regulate methyl carbon pathways and suggest that choline may play a critical role in

Cobalamin inactivation by nitrous oxide produces severe neurological impairment in fruit bats: protection by methionine and aggravation by folates

Energy Technology Data Exchange (ETDEWEB)

van der Westhuyzen, J.; Fernandes-Costa, F.; Metz, J.

1982-11-01

Nitrous oxide, which inactivates cobalamin when administered to fruit bats, results in severe neurological impairment leading to ataxia, paralysis and death. This occurs after about 6 weeks in animals depleted of cobalamin by dietary restriction, and after about 10 weeks in cobalamin replete bats. Supplementation of the diet with pteroylglutamic acid caused acceleration of the neurological impairment--the first unequivocal demonstration of aggravation of the neurological lesion in cobalamin deficiency by pteroylglutamic acid. The administration of formyltetrahydropteroylglutamic acid produced similar aggravation of the neurological lesion. Supplementation of the diet with methionine protected the bats from neurological impairment, but failed to prevent death. Methionine supplementation protected against the exacerbating effect of folate, preventing the development of neurological changes. These findings lend support to the hypothesis that the neurological lesion in cobalamin deficiency may be related to a deficiency in the methyl donor S-adenosylmethionine which follows diminished synthesis of methionine.

Safety and Waste Management for SAM Pathogen Methods

Science.gov (United States)

The General Safety and Waste Management page offers section-specific safety and waste management details for the pathogens included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Safety and Waste Management for SAM Biotoxin Methods

Science.gov (United States)

The General Safety and Waste Management page offers section-specific safety and waste management details for the biotoxins included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

A role for 11C-methionine PET imaging in ACTH-dependent Cushing's syndrome.

Science.gov (United States)

Koulouri, Olympia; Steuwe, Andrea; Gillett, Daniel; Hoole, Andrew C; Powlson, Andrew S; Donnelly, Neil A; Burnet, Neil G; Antoun, Nagui M; Cheow, Heok; Mannion, Richard J; Pickard, John D; Gurnell, Mark

2015-10-01

We report our experience of functional imaging with (11)C-methionine positron emission tomography-computed tomography (PET-CT) co-registered with 3D gradient echo (spoiled gradient recalled (SPGR)) magnetic resonance imaging (MRI) in the investigation of ACTH-dependent Cushing's syndrome. Twenty patients with i) de novo Cushing's disease (CD, n=10), ii) residual or recurrent hypercortisolism following first pituitary surgery (±radiotherapy; n=8) or iii) ectopic Cushing's syndrome (n=2) were referred to our centre for functional imaging studies between 2010 and 2015. Six of the patients with de novo CD and five of those with persistent/relapsed disease had a suspected abnormality on conventional MRI. All patients underwent (11)C-methionine PET-CT. For pituitary imaging, co-registration of PET-CT images with contemporaneous SPGR MRI (1 mm slice thickness) was performed, followed by detailed mapping of (11)C-methionine uptake across the sella in three planes (coronal, sagittal and axial). This allowed us to determine whether suspected adenomas seen on structural imaging exhibited focal tracer uptake on functional imaging. In seven of ten patients with de novo CD, asymmetric (11)C-methionine uptake was observed within the sella, which co-localized with the suspected site of a corticotroph microadenoma visualised on SPGR MRI (and which was subsequently confirmed histologically following successful transsphenoidal surgery (TSS)). Focal (11)C-methionine uptake that correlated with a suspected abnormality on pituitary MRI was seen in five of eight patients with residual or recurrent Cushing's syndrome following first TSS (and pituitary radiotherapy in two cases). Two patients elected to undergo repeat TSS with histology confirming a corticotroph tumour in each case. In two patients with the ectopic ACTH syndrome, (11)C-methionine was concentrated in sites of distant metastases, with minimal uptake in the sellar region. (11)C-methionine PET-CT can aid the detection of

The role of catechol-O-methyltransferase in catechol-enhanced erythroid differentiation of K562 cells

Energy Technology Data Exchange (ETDEWEB)

Suriguga,; Li, Xiao-Fei; Li, Yang; Yu, Chun-Hong; Li, Yi-Ran; Yi, Zong-Chun, E-mail: yizc@buaa.edu.cn

2013-12-15

Catechol is widely used in pharmaceutical and chemical industries. Catechol is also one of phenolic metabolites of benzene in vivo. Our previous study showed that catechol improved erythroid differentiation potency of K562 cells, which was associated with decreased DNA methylation in erythroid specific genes. Catechol is a substrate for the catechol-O-methyltransferase (COMT)-mediated methylation. In the present study, the role of COMT in catechol-enhanced erythroid differentiation of K562 cells was investigated. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation and induced mRNA expression of erythroid specific genes in K562 cells. Treatment with catechol caused a time- and concentration-dependent increase in guaiacol concentration in the medium of cultured K562 cells. When COMT expression was knocked down by COMT shRNA expression in K562 cells, the production of guaiacol significantly reduced, and the sensitivity of K562 cells to cytotoxicity of catechol significantly increased. Knockdown of COMT expression by COMT shRNA expression also eliminated catechol-enhanced erythroid differentiation of K562 cells. In addition, the pre-treatment with methyl donor S-adenosyl-L-methionine or its demethylated product S-adenosyl-L-homocysteine induced a significant increase in hemin-induced Hb synthesis in K562 cells and the mRNA expression of erythroid specific genes. These findings indicated that O-methylation catalyzed by COMT acted as detoxication of catechol and involved in catechol-enhanced erythroid differentiation of K562 cells, and the production of S-adenosyl-L-homocysteine partly explained catechol-enhanced erythroid differentiation. - Highlights: • Catechol enhanced hemin-induced hemoglobin accumulation. • COMT-catalyzed methylation acted as detoxication of catechol. • COMT involved in catechol-enhanced erythroid differentiation.

The role of catechol-O-methyltransferase in catechol-enhanced erythroid differentiation of K562 cells

International Nuclear Information System (INIS)

Suriguga,; Li, Xiao-Fei; Li, Yang; Yu, Chun-Hong; Li, Yi-Ran; Yi, Zong-Chun

2013-01-01

Catechol is widely used in pharmaceutical and chemical industries. Catechol is also one of phenolic metabolites of benzene in vivo. Our previous study showed that catechol improved erythroid differentiation potency of K562 cells, which was associated with decreased DNA methylation in erythroid specific genes. Catechol is a substrate for the catechol-O-methyltransferase (COMT)-mediated methylation. In the present study, the role of COMT in catechol-enhanced erythroid differentiation of K562 cells was investigated. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation and induced mRNA expression of erythroid specific genes in K562 cells. Treatment with catechol caused a time- and concentration-dependent increase in guaiacol concentration in the medium of cultured K562 cells. When COMT expression was knocked down by COMT shRNA expression in K562 cells, the production of guaiacol significantly reduced, and the sensitivity of K562 cells to cytotoxicity of catechol significantly increased. Knockdown of COMT expression by COMT shRNA expression also eliminated catechol-enhanced erythroid differentiation of K562 cells. In addition, the pre-treatment with methyl donor S-adenosyl-L-methionine or its demethylated product S-adenosyl-L-homocysteine induced a significant increase in hemin-induced Hb synthesis in K562 cells and the mRNA expression of erythroid specific genes. These findings indicated that O-methylation catalyzed by COMT acted as detoxication of catechol and involved in catechol-enhanced erythroid differentiation of K562 cells, and the production of S-adenosyl-L-homocysteine partly explained catechol-enhanced erythroid differentiation. - Highlights: • Catechol enhanced hemin-induced hemoglobin accumulation. • COMT-catalyzed methylation acted as detoxication of catechol. • COMT involved in catechol-enhanced erythroid differentiation

One-step synthesis of an {sup 18}F-labeled boron-derived methionine analog. A substitute for {sup 11}C-methionine?

Energy Technology Data Exchange (ETDEWEB)

Liu, Zhen; Lan, Xiaoli [Huazhong University of Science and Technology, Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Wuhan (China); Huazhong University of Science and Technology, Hubei Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Wuhan (China); Ehlerding, Emily B. [University of Wisconsin - Madison, Department of Medical Physics, Madison, WI (United States); Cai, Weibo [University of Wisconsin - Madison, Department of Medical Physics, Madison, WI (United States); University of Wisconsin - Madison, Department of Radiology, Madison, WI (United States); University of Wisconsin - Madison, Carbone Cancer Center, Madison, WI (United States)

2018-04-15

Amino acid-based tracers have been extensively investigated for positron emission tomography (PET) imaging of brain tumors, and {sup 11}C-methionine ({sup 11}C-MET) is one of the most extensively investigated. However, widespread clinical use of {sup 11}C-MET is challenging due to the short half-life of {sup 11}C and low radiolabeling yield. In this issue of the European Journal of Nuclear Medicine and Molecular Imaging, Yang and colleagues report an {sup 18}F-labeled boron-derived methionine analog, {sup 18}F-B-MET, as a potential substitute for {sup 11}C-MET in PET imaging of glioma. The push-button synthesis, highly efficient radiolabeling, and good imaging performance in glioma models make this tracer a promising candidate for future clinical translation. (orig.)

Conversion of nicotinic acid to trigonelline is catalyzed by N-methyltransferase belonged to motif B′ methyltransferase family in Coffea arabica

International Nuclear Information System (INIS)

Mizuno, Kouichi; Matsuzaki, Masahiro; Kanazawa, Shiho; Tokiwano, Tetsuo; Yoshizawa, Yuko; Kato, Misako

2014-01-01

Graphical abstract: Trigonelline synthase catalyzes the conversion of nicotinic acid to trigonelline. We isolated and characterized trigonelline synthase gene(s) from Coffea arabica. - Highlights: • Trigonelline is a major compound in coffee been same as caffeine is. • We isolated and characterized trigonelline synthase gene. • Coffee trigonelline synthases are highly homologous with coffee caffeine synthases. • This study contributes the fully understanding of pyridine alkaloid metabolism. - Abstract: Trigonelline (N-methylnicotinate), a member of the pyridine alkaloids, accumulates in coffee beans along with caffeine. The biosynthetic pathway of trigonelline is not fully elucidated. While it is quite likely that the production of trigonelline from nicotinate is catalyzed by N-methyltransferase, as is caffeine synthase (CS), the enzyme(s) and gene(s) involved in N-methylation have not yet been characterized. It should be noted that, similar to caffeine, trigonelline accumulation is initiated during the development of coffee fruits. Interestingly, the expression profiles for two genes homologous to caffeine synthases were similar to the accumulation profile of trigonelline. We presumed that these two CS-homologous genes encoded trigonelline synthases. These genes were then expressed in Escherichiacoli, and the resulting recombinant enzymes that were obtained were characterized. Consequently, using the N-methyltransferase assay with S-adenosyl[methyl- 14 C]methionine, it was confirmed that these recombinant enzymes catalyzed the conversion of nicotinate to trigonelline, coffee trigonelline synthases (termed CTgS1 and CTgS2) were highly identical (over 95% identity) to each other. The sequence homology between the CTgSs and coffee CCS1 was 82%. The pH-dependent activity curve of CTgS1 and CTgS2 revealed optimum activity at pH 7.5. Nicotinate was the specific methyl acceptor for CTgSs, and no activity was detected with any other nicotinate derivatives, or with

Conversion of nicotinic acid to trigonelline is catalyzed by N-methyltransferase belonged to motif B′ methyltransferase family in Coffea arabica

Energy Technology Data Exchange (ETDEWEB)

Mizuno, Kouichi, E-mail: koumno@akita-pu.ac.jp [Faculty of Bioresource Sciences, Akita Prefectural University, Akita City, Akita 010-0195 (Japan); Matsuzaki, Masahiro [Faculty of Bioresource Sciences, Akita Prefectural University, Akita City, Akita 010-0195 (Japan); Kanazawa, Shiho [Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610 (Japan); Tokiwano, Tetsuo; Yoshizawa, Yuko [Faculty of Bioresource Sciences, Akita Prefectural University, Akita City, Akita 010-0195 (Japan); Kato, Misako [Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610 (Japan)

2014-10-03

Graphical abstract: Trigonelline synthase catalyzes the conversion of nicotinic acid to trigonelline. We isolated and characterized trigonelline synthase gene(s) from Coffea arabica. - Highlights: • Trigonelline is a major compound in coffee been same as caffeine is. • We isolated and characterized trigonelline synthase gene. • Coffee trigonelline synthases are highly homologous with coffee caffeine synthases. • This study contributes the fully understanding of pyridine alkaloid metabolism. - Abstract: Trigonelline (N-methylnicotinate), a member of the pyridine alkaloids, accumulates in coffee beans along with caffeine. The biosynthetic pathway of trigonelline is not fully elucidated. While it is quite likely that the production of trigonelline from nicotinate is catalyzed by N-methyltransferase, as is caffeine synthase (CS), the enzyme(s) and gene(s) involved in N-methylation have not yet been characterized. It should be noted that, similar to caffeine, trigonelline accumulation is initiated during the development of coffee fruits. Interestingly, the expression profiles for two genes homologous to caffeine synthases were similar to the accumulation profile of trigonelline. We presumed that these two CS-homologous genes encoded trigonelline synthases. These genes were then expressed in Escherichiacoli, and the resulting recombinant enzymes that were obtained were characterized. Consequently, using the N-methyltransferase assay with S-adenosyl[methyl-{sup 14}C]methionine, it was confirmed that these recombinant enzymes catalyzed the conversion of nicotinate to trigonelline, coffee trigonelline synthases (termed CTgS1 and CTgS2) were highly identical (over 95% identity) to each other. The sequence homology between the CTgSs and coffee CCS1 was 82%. The pH-dependent activity curve of CTgS1 and CTgS2 revealed optimum activity at pH 7.5. Nicotinate was the specific methyl acceptor for CTgSs, and no activity was detected with any other nicotinate derivatives, or

Influence of dietary protein and excess methionine on choline needs for young bobwhite quail

Science.gov (United States)

Serafin, J.A.

1982-01-01

Experiments were conducted with young Bobwhite quail (Colinus virginianus) to investigate the effect of differing dietary protein levels and nondetrimental amounts of excess methionine on choline needs. Growth and feed consumption of quail fed an adequate (27.3%) protein purified diet supplemented with 2000 mg/kg of choline were unaffected by increasing the level of excess methionine to 1.75%; however, greater amounts (2.0%, 2.25%) of excess methionine depressed growth (P less than .01), reduced feed consumption (P less than .01), and decreased feed utilization (P less than .05). Quail fed a purified diet containing 13.85% protein and 515 mg/kg of choline grew poorly. Growth was unaffected by additional choline in this diet. Growth was suboptimal among quail fed purified diets containing adequate or high (41.55%) levels of protein in which choline was limiting; however, a high level of protein did not in itself affect performance. Growth was improved by supplemental choline in these diets. Growth of quail fed purified diets with up to 1.35% excess methionine which were limiting (531 mg/kg) in choline was less than that of groups fed 2000 mg/kg of added dietary choline (P less than .01); however, excess methionine did not significantly influence growth of quail fed choline-deficient diets. These experiments indicate that neither high dietary protein nor excess methionine, fed at non-growth-depressing levels, increases dietary choline needs for young Bobwhite quail.

ISO19770-1:2012 SAM process guidance

CERN Document Server

Canavan, Rory

2012-01-01

The pocket guide offers a concise summary of the principles of software asset management as conveyed by ISO 19770-1: 2012, and provides advice and guidance on how to kick-start your own SAM programme - something the Standard alone doesn't offer.

Safety and Waste Management for SAM Chemistry Methods

Science.gov (United States)

The General Safety and Waste Management page offers section-specific safety and waste management details for the chemical analytes included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Safety and Waste Management for SAM Radiochemical Methods

Science.gov (United States)

The General Safety and Waste Management page offers section-specific safety and waste management details for the radiochemical analytes included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

Targeting EphA2-Sam and Its Interactome: Design and Evaluation of Helical Peptides Enriched in Charged Residues.

Science.gov (United States)

Mercurio, Flavia A; Marasco, Daniela; Di Natale, Concetta; Pirone, Luciano; Costantini, Susan; Pedone, Emilia M; Leone, Marilisa

2016-11-17

The EphA2 receptor controls diverse physiological and pathological conditions and its levels are often upregulated in cancer. Targeting receptor overexpression, through modulation of endocytosis and consequent degradation, appears to be an appealing strategy for attacking tumor malignancy. In this scenario, the Sam domain of EphA2 plays a pivotal role because it is the site where protein regulators of endocytosis and stability are recruited by means of heterotypic Sam-Sam interactions. Because EphA2-Sam heterotypic complexes are largely based on electrostatic contacts, we have investigated the possibility of attacking these interactions with helical peptides enriched in charged residues. Several peptide sequences with high predicted helical propensities were designed, and detailed conformational analyses were conducted by diverse techniques including NMR, CD, and molecular dynamics (MD) simulations. Interaction studies were also performed by NMR, surface plasmon resonance (SPR), and microscale thermophoresis (MST) and led to the identification of two peptides capable of binding to the first Sam domain of Odin. These molecules represent early candidates for the generation of efficient Sam domain binders and antagonists of Sam-Sam interactions involving EphA2. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Seleno methionine-75 as a scanning agent for neuroblastoma

International Nuclear Information System (INIS)

Covington, E.E.; D'Angio, G.J.; Helson, L.; Romano, R.W.

1974-01-01

Neuroblastoma is a functioning tumor and patients with this tumor are known to excrete vanilmandelic acid and other degradation products of norepinephrine. It also accumulates and produces excess cystathionine for which methionine is a precursor in the normal anabolic pathway. This was the rationale for testing 75 Se-methionine as a possible scanning agent in patients with neuroblastoma. D'Angio et al reported the results of a preliminary investigation in which 3 of 4 patients with neuroblastoma, all with known metastases of the skull, had positive scans correctly localizing the disease. These preliminary data seemed encouraging, and further investigation was undertaken. The results are reported

Methionine-supplemented diet affects the expression of cardiovascular disease-related genes and increases inflammatory cytokines in mice heart and liver.

Science.gov (United States)

Aissa, Alexandre Ferro; Amaral, Catia Lira do; Venancio, Vinicius Paula; Machado, Carla da Silva; Hernandes, Lívia Cristina; Santos, Patrick Wellington da Silva; Curi, Rui; Bianchi, Maria de Lourdes Pires; Antunes, Lusânia Maria Greggi

2017-01-01

Some important environmental factors that influence the development of cardiovascular diseases (CVD) include tobacco, excess alcohol, and unhealthy diet. Methionine obtained from the diet participates in the synthesis of DNA, proteins, lipids and affects homocysteine levels, which is associated with the elevated risk for CVD development. Therefore, the aim of this study was to investigate the manner in which dietary methionine might affect cellular mechanisms underlying CVD occurrence. Swiss albino mice were fed either control (0.3% DL-methionine), methionine-supplemented (2% DL-methionine), or a methionine-deprived diet (0% DL-methionine) over a 10-week period. The parameters measured included plasma homocysteine concentrations, oxidative stress by reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, levels of inflammatory cytokines IL-1ß, TNF-α, and IL-6, as well as expression of genes associated with CVD. The levels of apolipoprotein A5 (APOA5), a regulator of plasma triglycerides, were measured. The methionine-supplemented diet increased oxidative stress by lowering the GSH/GSSG ratio in heart tissues and decreased expression of the genes Apob, Ctgf, Serpinb2, Spp1, Il1b, and Sell, but elevated expression of Thbs4, Tgfb2, Ccr1, and Vegfa. Methionine-deprived diet reduced expression of Col3a1, Cdh5, Fabp3, Bax, and Hbegf and increased expression of Sell, Ccl5, Itga2, Birc3, Msr1, Bcl2a1a, Il1r2, and Selp. Methionine-deprived diet exerted pro-inflammatory consequences as evidenced by elevated levels of cytokines IL-1ß, TNF-α, and IL-6 noted in liver. Methionine-supplemented diet increased hepatic IL-6 and cardiac TNF-α. Both methionine supplementation and deprivation lowered hepatic levels of APOA5. In conclusion, data demonstrated that a methionine-supplemented diet modulated important biological processes associated with high risk of CVD development.

Investigation of the metal binding site in methionine aminopeptidase by density functional theory

DEFF Research Database (Denmark)

Jørgensen, Anne Techau; Norrby, Per-Ola; Liljefors, Tommy

2002-01-01

All methionine aminopeptidases exhibit the same conserved metal binding site. The structure of this site with either Co2+ ions or Zn2+ ions was investigated using density functional theory. The calculations showed that the structure of the site was not influenced by the identity of the metal ions....... This was the case for both of the systems studied; one based on the X-ray structure of the human methionine aminopeptidase type 2 (hMetAP-2) and the other based on the X-ray structure of the E. coli methionine aminopeptidase type 1 (eMetAP-1). Another important structural issue is the identity of the bridging...

SAM-CE, Time-Dependent 3-D Neutron Transport, Gamma Transport in Complex Geometry by Monte-Carlo

International Nuclear Information System (INIS)

2003-01-01

1 - Nature of physical problem solved: The SAM-CE system comprises two Monte Carlo codes, SAM-F and SAM-A. SAM-F supersedes the forward Monte Carlo code, SAM-C. SAM-A is an adjoint Monte Carlo code designed to calculate the response due to fields of primary and secondary gamma radiation. The SAM-CE system is a FORTRAN Monte Carlo computer code designed to solve the time-dependent neutron and gamma-ray transport equations in complex three-dimensional geometries. SAM-CE is applicable for forward neutron calculations and for forward as well as adjoint primary gamma-ray calculations. In addition, SAM-CE is applicable for the gamma-ray stage of the coupled neutron-secondary gamma ray problem, which may be solved in either the forward or the adjoint mode. Time-dependent fluxes, and flux functionals such as dose, heating, count rates, etc., are calculated as functions of energy, time and position. Multiple scoring regions are permitted and these may be either finite volume regions or point detectors or both. Other scores of interest, e.g., collision and absorption densities, etc., are also made. 2 - Method of solution: A special feature of SAM-CE is its use of the 'combinatorial geometry' technique which affords the user geometric capabilities exceeding those available with other commonly used geometric packages. All nuclear interaction cross section data (derived from the ENDF for neutrons and from the UNC-format library for gamma-rays) are tabulated in point energy meshes. The energy meshes for neutrons are internally derived, based on built-in convergence criteria and user- supplied tolerances. Tabulated neutron data for each distinct nuclide are in unique and appropriate energy meshes. Both resolved and unresolved resonance parameters from ENDF data files are treated automatically, and extremely precise and detailed descriptions of cross section behaviour is permitted. Such treatment avoids the ambiguities usually associated with multi-group codes, which use flux

Distinction between the Cfr Methyltransferase Conferring Antibiotic Resistance and the Housekeeping RlmN Methyltransferase

DEFF Research Database (Denmark)

Atkinson, Gemma C; Hansen, Lykke H; Tenson, Tanel

2013-01-01

The cfr gene encodes the Cfr methyltransferase that primarily methylates C-8 in A2503 of 23S rRNA in the peptidyl transferase region of bacterial ribosomes. The methylation provides resistance to six classes of antibiotics of clinical and veterinary importance. The rlmN gene encodes the Rlm......N methyltransferase that methylates C-2 in A2503 in 23S rRNA and A37 in tRNA, but RlmN does not significantly influence antibiotic resistance. The enzymes are homologous and use the same mechanism involving radical S-adenosyl methionine to methylate RNA via an intermediate involving a methylated cysteine....... The differentiation between the two classes is supported by previous and new experimental evidence from antibiotic resistance, primer extensions, and mass spectrometry. Finally, evolutionary aspects of the distribution of Cfr- and RlmN-like enzymes are discussed....

Methionine supplementation in the productive efficiency, carcass ...

African Journals Online (AJOL)

The effect of dietary methionine supplementation at varying levels on the productive efficiency, carcass characteristics and economics of growing indigenous turkey was investigated. Four Isocaloric and Isonitrogenous diets were formulated. The diets were supplemented with 0.00%, 0.05%, 0.10%, and 0.15% respectively.

Fluoresence quenching of riboflavin in aqueous solution by methionin and cystein

International Nuclear Information System (INIS)

Droessler, P.; Holzer, W.; Penzkofer, A.; Hegemann, P.

2003-01-01

The fluorescence quantum distributions, fluorescence quantum yields, and fluorescence lifetimes of riboflavin in methanol, DMSO, water, and aqueous solutions of the sulphur atom containing amino acids methionin and cystein have been determined. In methanol, DMSO, and water (pH=4-8) only dynamic fluorescence reduction due to intersystem crossing and internal conversion is observed. In aqueous methionin solutions of pH=5.25-9 a pH independent static and dynamic fluorescence quenching occurs probably due to riboflavin anion-methionin cation pair formation. In aqueous cystein solutions (pH range from 4.15 to 9) the fluorescence quenching increases with rising pH due to cystein thiolate formation. The cystein thiol form present at low pH does not react with neutral riboflavin. Cystein thiolate present at high pH seems to react with neutral riboflavin causing riboflavin deprotonation (anion formation) by cystein thiolate reduction to the cystein thiol form

Bio-efficacy comparison of herbal-methionine and DL-methionine based on performance and blood parameters of broiler chickens

Directory of Open Access Journals (Sweden)

Sheila Hadinia

2014-06-01

Full Text Available This study was conducted to compare the bio-efficacy of herbal methionine (H-Met relative to DL-methionine (DL-Met on 160 “Ross 308” broiler chickens. DL-Met and H-Met were added to the basal diet in eight experimental treatments with three and four concentrations respectively in starter, grower and finisher period. Blood parameters which were measured at 24 and 42 days of age consisted of: serum proteins (total protein, albumin and globulin, serum uric acid, serum fats (low density lipoprotein, high density lipoprotein, triglyceride and cholesterol and serum enzymes (alanine amino transaminase and aspartate amino transaminase. Completely randomized design, multi-exponential and multilinear regressions were used to determine bio-efficacy of H-Met in terms of performance and blood parameters of broilers. The results showed that supplemented methionine (Met sources had no significant effect on blood parameters at 24 day of age. At 42 day of age the amounts of globulin and serum high density lipoprotein (HDL increased with supplemented Met, (p < 0.05. Regression analysis revealed that H-Met was 55.00, 71.00, 78.00, 47.00, 58.00 and 73.00% as efficacious as DL-Met for body weight gain, feed intake, feed conversion ratio, albumin, globulin and high density lipoprotein criteria, respectively. The average of bio-efficacy of H-Met compared to DL-Met was 67.00% and 59.00% on average across performance criteria and blood criteria respectively and was 63.00% across these two criteria tested. The results of the present study indicated that H-Met can be administered as a new and a natural source of Met in poultry industry.

The ALICE Glance Shift Accounting Management System (SAMS)

Science.gov (United States)

Martins Silva, H.; Abreu Da Silva, I.; Ronchetti, F.; Telesca, A.; Maidantchik, C.

2015-12-01

ALICE (A Large Ion Collider Experiment) is an experiment at the CERN LHC (Large Hadron Collider) studying the physics of strongly interacting matter and the quark-gluon plasma. The experiment operation requires a 24 hours a day and 7 days a week shift crew at the experimental site, composed by the ALICE collaboration members. Shift duties are calculated for each institute according to their correlated members. In order to ensure the full coverage of the experiment operation as well as its good quality, the ALICE Shift Accounting Management System (SAMS) is used to manage the shift bookings as well as the needed training. ALICE SAMS is the result of a joint effort between the Federal University of Rio de Janeiro (UFRJ) and the ALICE Collaboration. The Glance technology, developed by the UFRJ and the ATLAS experiment, sits at the basis of the system as an intermediate layer isolating the particularities of the databases. In this paper, we describe the ALICE SAMS development process and functionalities. The database has been modelled according to the collaboration needs and is fully integrated with the ALICE Collaboration repository to access members information and respectively roles and activities. Run, period and training coordinators can manage their subsystem operation and ensure an efficient personnel management. Members of the ALICE collaboration can book shifts and on-call according to pre-defined rights. ALICE SAMS features a user profile containing all the statistics and user contact information as well as the Institutes profile. Both the user and institute profiles are public (within the scope of the collaboration) and show the credit balance in real time. A shift calendar allows the Run Coordinator to plan data taking periods in terms of which subsystems shifts are enabled or disabled and on-call responsible people and slots. An overview display presents the shift crew present in the control room and allows the Run Coordination team to confirm the presence

Expression of a methionine-rich storage albumin from the Brazil nut (Bertholletia excelsa H.B.K., Lecythidaceae in transgenic bean plants (Phaseolus vulgaris L., Fabaceae

Directory of Open Access Journals (Sweden)

Aragão F.J.L.

1999-01-01

Full Text Available Bean (Phaseolus vulgaris, an important component in the diet of people in developing countries, has low levels of the essential amino acid, methionine. We have attempted to correct this deficiency by introducing a transgene coding for a methionine-rich storage albumin from the Brazil nut via biolistic methods. The transgene's coding sequence was driven by a doubled 35S CaMV promoter and AMV enhancer sequences. The transgene was stable and correctly expressed in homozygous R2 to R5 seeds. In two of the five transgenic lines the methionine content was significantly increased (14 and 23% over the values found in untransformed plants.

Acute Administration of Methionine Affects Performance of Swiss ...

African Journals Online (AJOL)

olayemitoyin

The effect of methionine on learning and memory in mice was investigated using Morris ... neurological disorders by excitotoxicity and ... Central cholinergic system plays a major role in ... acetylcholinesterase leads to increased levels of brain.

1H, 15N and 13C NMR Assignments of Mouse Methionine Sulfoxide Reductase B2

Science.gov (United States)

Breivik, Åshild S.; Aachmann, Finn L.; Sal, Lena S.; Kim, Hwa-Young; Del Conte, Rebecca; Gladyshev, Vadim N.; Dikiy, Alexander

2011-01-01

A recombinant mouse methionine-r-sulfoxide reductase 2 (MsrB2ΔS) isotopically labeled with 15N and 15N/13C was generated. We report here the 1H, 15N and 13C NMR assignments of the reduced form of this protein. PMID:19636904

1-13C; methyl-2H3 methionine kinetics in humans: Methionine conservation and cystine sparing

International Nuclear Information System (INIS)

Storch, K.J.; Wagner, D.A.; Burke, J.F.; Young, V.R.

1990-01-01

Methionine (Met) conservation in healthy young adult men (4/diet group) was explored by supplying one of the following three L-amino acid based diets: (1) adequate Met but no cystine; (2) neither Met nor cystine; or (3) no Met but cystine supplementation. After 5 days, subjects received a continuous intravenous infusion of L-[1-13C; methyl-2H3]Met for 5 h while the diet was given as small isocaloric isonitrogenous meals. Estimates were made of rates of Met incorporation into protein synthesis (S) and release from body proteins (B), transmethylation (TM), remethylation of homocysteine (RM), and transsulfuration (TS). For the adequate Met diet, the rates were S = 24 +/- 2, B = 18 +/- 1, TM = 12.4 +/- 1.7, RM = 4.7 +/- 1.1, and TS = 7.6 +/- 0.6 (SE) mumol.kg-1.h-1. The sulfur amino acid-devoid diet significantly (P less than 0.05) reduced S, TM, RM, and TS. Supplementation of this diet with cystine reduced Met oxidation (P = 0.05). Therefore, two loci are quantitatively important regulatory points in Met conservation in vivo: (1) the distribution of Met between the pathways of protein anabolism and TM (Met locus) and (2) the distribution of homocysteine between RM and TS (homocysteine locus)

Nutritional levels of digestible methionine + cystine to brown-egg laying hens from 50 to 66 weeks of age

Directory of Open Access Journals (Sweden)

Clauber Polese

2012-07-01

Full Text Available The objective of this study was to determine the requirement of digestible methionine + cystine of brown-eggs laying hens from 50 to 66 weeks age at the end of the first production cycle. The design was completely randomized, with 150 Brown Shaver hens, which were distributed in five treatments with six replications of five birds each. Birds received a basal diet with 2857 kcal/kg metabolizable energy and 15.97% crude protein, supplemented with 0.132; 0.174, 0.215, 0.256 and 0.298% DL-methionine (98%, in order to provide 0.572, 0.613, 0.653, 0.693 and 0.734% digestible methionine + cystine. The levels of digestible methionine + digestible cystine followed, respectively, the relations of 67, 72, 77, 81 and 86% with lysine fixed at 0.851%. Feed intake, methionine + cystine intake, feed conversion per dozen eggs, egg weigth and mass, percentage of egg components, internal egg quality and weight gain were evaluated. Methionine + cystine levels showed a quadratic effect on feed conversion per dozen eggs and egg weight, a linear effect on feed conversion per kilogram of eggs and percentage of albumen. There was also a positive linear effect on yolk percentage. The methionine + cystine requirement was estimated at 0.572%, corresponding to 682 mg of digestible methionine + cystine/bird/day.

Neuropeptides labelled with [sup 35]S

Energy Technology Data Exchange (ETDEWEB)

Kaspersen, F.M.; Nispen, J.W. van; Sperling, E.M.G.; Vader, J.F. (Organon Int BV, Oss (Netherlands))

1993-01-01

Methionine and cysteine containing peptides can be labelled with [sup 35]S by coupling of [sup 35]S-cysteine or [sup 35]S-methionine with a large excess of suitability protected peptide precursors. This is illustrated for [pGlu[sup 4], Cyt[sup 6

SAM Technical Review Committee Final Report: Summary and Key Recommendations from the Onsite TRC Meeting Held April 22-23, 2013

Energy Technology Data Exchange (ETDEWEB)

Blair, N.; Dobos, S.; Janzou, S.; Gilman, P.; Freeman, J.; Kaffine, L.

2013-08-01

The System Advisor Model (SAM) is a broad and robust set of models and frameworks for analyzing both system performance and system financing. It does this across a range of technologies dominated by solar technologies including photovoltaics (PV) and concentrated solar power (CSP). The U.S. Department of Energy (DOE) Solar Energy Technology Program requested the SAM development team to review the photovoltaic performance modeling with the development community and specifically, with the independent engineering community. The report summarizes the major effort for this technical review committee (TRC).

Quantitative autoradiographic investigations on hairs, skin, and nails with the precursors 35S-cystine or 35S-methionine and 3H-thymidine respectively in animal experiments

International Nuclear Information System (INIS)

Schmiegelow, P.; Berndt, G.; Lindner, J.; Puschmann, M.

1981-01-01

By quantitative autoradiographic methods we tested the possible influence of the sulphurous amino acid L-cystine on the growth of hair, skin and nails. In the 3 H-thymidine autoradiographic method the tracing index (percentage of traced cell cores in relation to the total number of cell cores of a cell population) is calculated morphologically. In the 35 S-cystine and the 35 S-methionine autoradiography a quantification is carried out by applying the microscopic photometer for the investigation of defined hair root cross-sections. Measured values are indicated which depend on dosage and on the incorporation time. The investigation of other agents provoking negative or positive reactions of the hair growth by means of this method will have to be realized. Unlabelled L-cystine seems to promote the growth of hairs, epidermic basal cells and of germ cells of mouse nails, according to experiences made in animal experiments. The latter findings will have to be completed and confirmed by additional experiments. (orig.) [de

Crystal structure and dimerization equilibria of PcoC, a methionine-rich copper resistance protein from Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Wernimont, A.K.; Huffman, D.L.; Finney, L.A.; Demeler, B.; O' Halloran, T.V.; Rosenzweig, A.C.

2010-03-08

PcoC is a soluble periplasmic protein encoded by the plasmid-born pco copper resistance operon of Escherichia coli. Like PcoA, a multicopper oxidase encoded in the same locus and its chromosomal homolog CueO, PcoC contains unusual methionine rich sequences. Although essential for copper resistance, the functions of PcoC, PcoA, and their conserved methionine-rich sequences are not known. Similar methionine motifs observed in eukaryotic copper transporters have been proposed to bind copper, but there are no precedents for such metal binding sites in structurally characterized proteins. The high-resolution structures of apo PcoC, determined for both the native and selenomethionine-containing proteins, reveal a seven-stranded barrel with the methionines unexpectedly housed on a solvent-exposed loop. Several potential metal-binding sites can be discerned by comparing the structures to spectroscopic data reported for copper-loaded PcoC. In the native structure, the methionine loop interacts with the same loop on a second molecule in the asymmetric unit. In the selenomethionine structure, the methionine loops are more exposed, forming hydrophobic patches on the protein surface. These two arrangements suggest that the methionine motifs might function in protein-protein interactions between PcoC molecules or with other methionine-rich proteins such as PcoA. Analytical ultracentrifugation data indicate that a weak monomer-dimer equilibrium exists in solution for the apo protein. Dimerization is significantly enhanced upon binding Cu(I) with a measured {Delta}({Delta}G{sup o}) {le} -8.0 kJ/mole, suggesting that copper might bind at the dimer interface.

Crystal growth and structure of L-methionine L-methioninium hydrogen maleate-a new NLO material

International Nuclear Information System (INIS)

Natarajan, Subramanian; Rajan Devi, Neelamagam; Britto Dhas, Sathiya Dhas Martin; Athimoolam, Shanmuganarayanan

2008-01-01

A new organic nonlinear optical (NLO) crystal from the amino acid family, viz., L-methionine L-methioninium hydrogen maleate (LMMM), has been grown by slow evaporation method from aqueous solution. Bulk crystals were grown using submerged seed solution method. The structure was elucidated using the single crystal x-ray diffraction data. The compound crystallized in the space group P2 1 and the unit cell contains a protonated L-methioninium cation and a zwitterionic methionine residue plus a maleate anion. The backbone conformation angles Ψ 1 and Ψ 2 are in cis and trans configurations for both the methionine and methioninium residues, respectively. Amino and carboxyl groups of the methioninium and methionine residues are connected through N-H...O hydrogen bonds leading to a ring R 2 2 (10) motif.

Fabrication and tribological properties of self-assembled monolayer of n-alkyltrimethoxysilane on silicon: Effect of SAM alkyl chain length

International Nuclear Information System (INIS)

Huo, Lixia; Du, Pengcheng; Zhou, Hui; Zhang, Kaifeng; Liu, Peng

2017-01-01

Highlights: • n-Alkyltrimethoxysilanes with various chain lengths were self-assembled on silicon. • Effect of alkyl chain lengths (C6, C12, or C18) on the SAMs was investigated. • Surface roughness of the SAMs decreased with increasing the alkyl chain lengths. • The C 12 -SAM possessed superior friction reduction and wear resistance. - Abstract: It is well known that the self-assembled organic molecules on a solid surface exhibit the friction-reducing performance. However, the effect of the molecular size of the self-assembled organic molecules has not been established. In the present work, self-assembled monolayers (SAMs) of n-alkyltrimethoxysilanes with different alkyl chain lengths (C 6 , C 12 , or C 18 ) were fabricated on silicon substrate. The water contact angles of the SAMs increased from 26.8° of the hydroxylated silicon substrate to near 60° after self-assembly. The atomic force microscopy (AFM) analysis results showed that the mean roughness (R a ) of the SAMs decreased with increasing the alkyl chain length. The tribological properties of the SAMs sliding against Al 2 O 3 ball were evaluated on an UMT-2 tribometer, and the worn surfaces of the samples were analyzed by means of Nano Scratch Tester and surface profilometry. It was found that lowest friction coefficient and smallest width of wear were achieved with the SAMs of C 12 alkyl chain (C 12 -SAM). The superior friction reduction and wear resistance of the SAMs in comparison with the bare silicon substrate are attributed to good adhesion of the self-assembled films to the substrate, especially the C 12 -SAM with desirable alkyl chain length.

Noncompetitive inhibition of indolethylamine-N-methyltransferase by N,N-dimethyltryptamine and N,N-dimethylaminopropyltryptamine.

Science.gov (United States)

Chu, Uyen B; Vorperian, Sevahn K; Satyshur, Kenneth; Eickstaedt, Kelsey; Cozzi, Nicholas V; Mavlyutov, Timur; Hajipour, Abdol R; Ruoho, Arnold E

2014-05-13

Indolethylamine-N-methyltransferase (INMT) is a Class 1 transmethylation enzyme known for its production of N,N-dimethyltryptamine (DMT), a hallucinogen with affinity for various serotonergic, adrenergic, histaminergic, dopaminergic, and sigma-1 receptors. DMT is produced via the action of INMT on the endogenous substrates tryptamine and S-adenosyl-l-methionine (SAM). The biological, biochemical, and selective small molecule regulation of INMT enzyme activity remain largely unknown. Kinetic mechanisms for inhibition of rabbit lung INMT (rabINMT) by the product, DMT, and by a new novel tryptamine derivative were determined. After Michaelis-Menten and Lineweaver-Burk analyses had been applied to study inhibition, DMT was found to be a mixed competitive and noncompetitive inhibitor when measured against tryptamine. The novel tryptamine derivative, N-[2-(1H-indol-3-yl)ethyl]-N',N'-dimethylpropane-1,3-diamine (propyl dimethyl amino tryptamine or PDAT), was shown to inhibit rabINMT by a pure noncompetitive mechanism when measured against tryptamine with a Ki of 84 μM. No inhibition by PDAT was observed at 2 mM when it was tested against structurally similar Class 1 methyltransferases, such as human phenylethanolamine-N-methyltransferase (hPNMT) and human nicotinamide-N-methyltransferase (hNNMT), indicating selectivity for INMT. The demonstration of noncompetitive mechanisms for INMT inhibition implies the presence of an inhibitory allosteric site. In silico analyses using the computer modeling software Autodock and the rabINMT sequence threaded onto the human INMT (hINMT) structure (Protein Data Bank entry 2A14 ) identified an N-terminal helix-loop-helix non-active site binding region of the enzyme. The energies for binding of DMT and PDAT to this region of rabINMT, as determined by Autodock, were -6.34 and -7.58 kcal/mol, respectively. Assessment of the allosteric control of INMT may illuminate new biochemical pathway(s) underlying the biology of INMT.

Bacterial contribution to iodine volatilization in the environment

Energy Technology Data Exchange (ETDEWEB)

Amachi, S; Kasahara, M; Fujii, T [Chiba Univ., Dept. of Bioresources Chemistry, Matsudo, Chiba (Japan); Muramatsu, Y [National Inst. of Radiological Sciences, Chiba (Japan)

2003-09-01

The roles of microorganisms in iodine volatilization from the environment were studied. More than 100 bacterial strains were isolated from various environments such as soils, seawater and marine sediments, and were examined their capacities for volatilizing iodine. Approximately 40% of these bacteria showed significant capacities for volatilizing iodine. Gas chromatographic determinations revealed that the chemical species of gaseous iodine is methyl iodide (CH{sub 3}I). Phylogenetic analysis based on 16S ribosomal DNA showed that these 'iodine-volatilizing bacteria' are widely distributed through the bacterial domain. The iodide-methylating reaction was mediated by an enzyme protein with S-adenosyl-L-methionine (SAM) as the methyl donor. We then estimated bacterial contribution to iodine volatilization from soils. Iodine in soils was volatilized mainly as CH{sub 3}I. CH{sub 3}I emission was enhanced in the presence of glucose or yeast extract, but was inhibited by autoclaving of soils. Little CH{sub 3}I was produced under anaerobic conditions. Furthermore, the addition of streptomycin and tetracycline, antibiotics which inhibit bacterial growth, strongly inhibited CH{sub 3}I emission, while a fungal inhibitor cycloheximide caused little effect. These results suggest that iodine in soils is volatilized as CH{sub 3}I mainly by the action of aerobic soil bacteria. Similar experiment was carried out by using sea water samples. The emission of iodine from sea waters occurred biologically, and bacterial (and also other microbial) contribution was confirmed. Our results suggest that iodine is methylated and volatilized into the atmosphere as a result of bacterial activities. Since bacteria are so abundant and widespread in the environments, they may significantly contribute to global iodine volatilization. This indicates that if {sup 129}I would be released from nuclear facilities, weapons testing or ground storage of nuclear wastes, the pathway of volatilization by

Atmospheric modeling of Mars CH4 subsurface clathrates releases mimicking SAM and 2003 Earth-based detections

Science.gov (United States)

Pla-García, J.; Rafkin, S. C.

2017-12-01

The aim of this work is to establish the amount of mixing during all martian seasons to test whether CH4 releases inside or outside of Gale crater are consistent with MSL-SAM observations. Several modeling scenarios were configured, including instantaneous and steady releases, both inside and outside the crater. A simulation to mimic the 2003 Earth-based detections (Mumma et al. 2009 or M09) was also performed. In the instantaneous release inside Gale experiments, Ls270 was shown to be the faster mixing season when air within and outside the crater was well mixed: all tracer mass inside the crater is diluted after just 8 hours. The mixing of near surface crater air with the external environment in the rest of the year is potentially rapid but slower than Ls270.In the instantaneous release outside Gale (NW) experiment, in just 12 hours the CH4 that makes it to the MSL landing location is diluted by six orders of magnitude. The timescale of mixing in MRAMS experiments is on the order of 1 sol regardless of season. The duration of the CH4 peak observed by SAM is 100 sols. Therefore there is a steady release inside the crater, or there is a very large magnitude steady release outside the crater. In the steady release Gale experiments, CH4 flux rate from ground is 1.8 kg m-2 s-1 (derived from Gloesener et al. 2017 clathrates fluxes) and it is not predictive. In these experiments, 200 times lower CH4 values detected by SAM are modeled around MSL location. There are CH4 concentration variations of orders of magnitude depending on the hour, so timing of SAM measurements is important. With a larger (but further away) outside crater release area compared to inside, similar CH4 values around MSL are modeled, so distance to source is important. In the steady experiments mimicking M09 detection release area, only 12 times lower CH4 values detected by SAM are modeled around MSL. The highest value in the M09 modeled scenario (0.6 ppbv) is reached in Ls270. This value is the

Fabrication and Surface Properties of Composite Films of SAM/Pt/ZnO/SiO 2

KAUST Repository

Yao, Ke Xin

2008-12-16

Through synthetic architecture and functionalization with self-assembled monolayers (SAMs), complex nanocomposite films of SAM/Pt/ZnO/SiO2 have been facilely prepared in this work. The nanostructured films are highly uniform and porous, showing a wide range of tunable wettabilities from superhydrophilicity to superhydrophobicity (water contact angles: 0° to 170°). Our approach offers synthetic flexibility in controlling film architecture, surface topography, coating texture, crystallite size, and chemical composition of modifiers (e.g., SAMs derived from alkanethiols). For example, wettability properties of the nanocomposite films can be finely tuned with both inorganic phase (i.e., ZnO/SiO2 and Pt/ZnO/SiO2) and organic phase (i.e., SAMs on Pt/ZnO/SiO2). Due to the presence of catalytic components Pt/ZnO within the nanocomposites, surface reactions of the organic modifiers can further take place at room temperature and elevated temperatures, which provides a means for SAM formation and elimination. Because the Pt/ZnO forms an excellent pair of metal-semiconductors for photocatalysis, the anchored SAMs can also be modified or depleted by UV irradiation (i.e., the films possess self-cleaning ability). Potential applications of these nanocomposite films have been addressed. Our durability tests also confirm that the films are thermally stable and structurally robust in modification- regeneration cycles. © 2008 American Chemical Society.

Secretion Of Methionine By Microorganisms Associated With ...

African Journals Online (AJOL)

methionine were secreted after 96 hours and 72 hours respectively by the lactobacilli and Leuconostoc sp. Since lactic acid bacteria are micro-aerophilic, it is suggested that lactic acid bacteria (the two lactobacilli and Leuconostoc sp.), which are the major organisms involved in cassava fermentation for garri production, ...

Annals of SAM meeting `96. National meeting on precious metals; Anales de las jornadas SAM `96. Encuentro nacional de metales preciosos

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

Works are presented at the SAM meeting `96 of the Argentine Materials Association. The papers can be grouped under the following main topics: physical metallurgy; ceramics; polymers; precious metals; extractive metallurgy; corrosion; powder metallurgy. refs., ills.

Fabrication and tribological properties of self-assembled monolayer of n-alkyltrimethoxysilane on silicon: Effect of SAM alkyl chain length

Energy Technology Data Exchange (ETDEWEB)

Huo, Lixia [National Key Laboratory of Science and Technology on Vacuum Technology and Physics, Lanzhou Institute of Physics, Lanzhou, Gansu 730010 (China); Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Gansu 730000 (China); Du, Pengcheng [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Gansu 730000 (China); Zhou, Hui; Zhang, Kaifeng [National Key Laboratory of Science and Technology on Vacuum Technology and Physics, Lanzhou Institute of Physics, Lanzhou, Gansu 730010 (China); Liu, Peng, E-mail: pliu@lzu.edu.cn [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Gansu 730000 (China)

2017-02-28

Highlights: • n-Alkyltrimethoxysilanes with various chain lengths were self-assembled on silicon. • Effect of alkyl chain lengths (C6, C12, or C18) on the SAMs was investigated. • Surface roughness of the SAMs decreased with increasing the alkyl chain lengths. • The C{sub 12}-SAM possessed superior friction reduction and wear resistance. - Abstract: It is well known that the self-assembled organic molecules on a solid surface exhibit the friction-reducing performance. However, the effect of the molecular size of the self-assembled organic molecules has not been established. In the present work, self-assembled monolayers (SAMs) of n-alkyltrimethoxysilanes with different alkyl chain lengths (C{sub 6}, C{sub 12}, or C{sub 18}) were fabricated on silicon substrate. The water contact angles of the SAMs increased from 26.8° of the hydroxylated silicon substrate to near 60° after self-assembly. The atomic force microscopy (AFM) analysis results showed that the mean roughness (R{sub a}) of the SAMs decreased with increasing the alkyl chain length. The tribological properties of the SAMs sliding against Al{sub 2}O{sub 3} ball were evaluated on an UMT-2 tribometer, and the worn surfaces of the samples were analyzed by means of Nano Scratch Tester and surface profilometry. It was found that lowest friction coefficient and smallest width of wear were achieved with the SAMs of C{sub 12} alkyl chain (C{sub 12}-SAM). The superior friction reduction and wear resistance of the SAMs in comparison with the bare silicon substrate are attributed to good adhesion of the self-assembled films to the substrate, especially the C{sub 12}-SAM with desirable alkyl chain length.

The Combustion Experiment on the Sample Analysis at Mars (SAM) Instrument Suite on the Curiosity Rover

Science.gov (United States)

Stern, J. C.; Malespin, C. A.; Eigenbrode, J. L.; Graham, H. V.; Archer, P. D., Jr.; Brunner, A. E.; Freissinet, C.; Franz, H. B.; Fuentes, J.; Glavin, D. P.;

Tumour imaging by Positron Emission Tomography using fluorinase generated 5-[18F]fluoro-5-deoxyribose as a novel tracer

International Nuclear Information System (INIS)

Dall'Angelo, Sergio; Bandaranayaka, Nouchali; Windhorst, Albert D.; Vugts, Danielle J.; Born, Dion van der; Onega, Mayca; Schweiger, Lutz F.; Zanda, Matteo; O'Hagan, David

2013-01-01

Introduction: 5-[ 18 F]Fluoro-5-deoxyribose ([ 18 F]FDR) 3 was prepared as a novel monosaccharide radiotracer in a two-step synthesis using the fluorinase, a C-F bond forming enzyme, and a nucleoside hydrolase. The resulting [ 18 F]FDR 3 was then explored as a radiotracer for imaging tumours (A431 human epithelial carcinoma) by positron emission tomography in a mice model. Methods: 5-[ 18 F]Fluoro-5-deoxyribose ([ 18 F]FDR) 3, was prepared by incubating S-adenosyl-L-methionine (SAM) and [ 18 F]fluoride with the fluorinase enzyme, and then incubating the product of this reaction, [ 18 F]-5'-fluoro-5'-deoxadenosine ([ 18 F]FDA) 2, with an adenosine hydrolase to generate [ 18 F]FDR 3. The enzymes were freeze-dried and were used on demand by dissolution in buffer solution. The resulting [ 18 F]FDR 3 was then administered to four mice that had tumours induced from the A431 human epithelial carcinoma cell line. Results: The tumour (A431 human epithelial carcinoma) bearing mice were successfully imaged with [ 18 F]FDR 3. The radiotracer displayed good tumour imaging resolution. A direct comparison of the uptake and efflux of [ 18 F]FDR 3 with 2-[ 18 F]fluoro-2-deoxyglucose ([ 18 F]FDG) was made, revealing comparative tumour uptake and imaging potential over the first 10–20 min. The study revealed however that [ 18 F]FDR 3 does not accumulate in the tumour as efficiently as [ 18 F]FDG over longer time periods. Conclusions: [ 18 F]FDR 3 can be rapidly synthesised in a two enzyme protocol and used to image tumours in small animal models

Oxidation of Methionine by Tripropylammonium Fluorochromate-A Kinetic and Mechanistic Study

Directory of Open Access Journals (Sweden)

S. Sheik Mansoor

2011-01-01

Full Text Available The kinetics of oxidation of methionine (Met by tripropylammonium fluorochromate (TriPAFC has been studied in the presence of chloroacetic acid in aqueous acetic acid medium. The reaction is first order with respect to methionine, TriPAFC and acid. The reaction rate has been determined at different temperatures and activation parameters calculated. With an increase in the amount of acetic acid in its aqueous mixture, the rate increases. The reaction does not induce polymerization of acrylonitrile. A suitable mechanism has been proposed.

Kuula. Kuu artist Sam Sparro. Kuu plaat / Mart Juur

Index Scriptorium Estoniae

Juur, Mart, 1964-

2008-01-01

Artistist Sam Sparrost. Heliplaatidest: "Sex And The City" Original Motion Picture Soundtrack, "Maestro: Blue Note Trip", Melvin/Soo/Remmel/Julm "Geografix", Alanis Morrisette "Flavors Of Entanglement", Guillemots "Red"

Influence of Methionine Supplementation on Nicotine Teratogenicity ...

African Journals Online (AJOL)

Human and animal studies have shown that maternal tobacco smoking during pregnancy adversely affects pre and postnatal growth and increases the risk of fetal mortality. The aim of the present study was to determine the toxicity of nicotine and protective effect of methionine on the toxic effects of nicotine. Pregnant ...

Partitioning of L-methionine in aqueous two-phase systems containing poly(propylene glycol) and sodium phosphate salts

International Nuclear Information System (INIS)

Salabat, Alireza; Sadeghi, Rahmat; Moghadam, Somayeh Tiani; Jamehbozorg, Bahman

2011-01-01

Highlights: → Thermodynamics parameters for partitioning of L-methionine in ATPS. → Investigation of different effects on partition coefficient of the amino acid. → Propose the best condition for L-methionine partitioning. - Abstract: The partitioning behavior of L-methionine has been studied in aqueous two-phase systems of (poly(propylene glycol) + sodium phosphate salts + H 2 O) at different temperatures. The salts used were sodium di-hydrogen phosphate (NaH 2 PO 4 ), di-sodium hydrogen phosphate (Na 2 HPO 4 ) and tri-sodium phosphate (Na 3 PO 4 ). The effects of tie line length, salt type, and temperature on the partition coefficient of this amino acid have been studied. In addition, thermodynamic parameters (ΔH o , ΔS o and ΔG o ) as a function of temperature were calculated. The results showed that increasing tie line length led to decreasing of the partition coefficient. We also showed that the partition coefficients of the amino acid in the systems containing Na 3 PO 4 are greater than the other two salts. Moreover, it is verified that increasing temperature led to decreasing the partition coefficient. The experimental partition coefficient data are correlated using a modified virial-type model.

Séries temporais de NDVI do sensor SPOT Vegetation e algoritmo SAM aplicados ao mapeamento de cana‑de‑açúcar

Directory of Open Access Journals (Sweden)

Luiz Eduardo Vicente

2012-09-01

Full Text Available O objetivo deste trabalho foi avaliar o mapeamento de área de cana‑de‑açúcar por meio de série temporal, de seis anos de dados do índice de vegetação por diferença normalizada (NDVI, oriundos do sensor Vegetation, a bordo do satélite "système pour l'observation de la Terre" (SPOT. Três classes de cobertura do solo (cana‑de‑açúcar, pasto e floresta, do Estado de São Paulo, foram selecionadas como assinaturas espectro‑temporais de referência, que serviram como membros extremos ("endmembers" para classificação com o algoritmo "spectral angle mapper" (SAM. A partir desta classificação, o mapeamento da área de cana‑de‑açúcar foi realizado com uso de limiares na imagem-regra do SAM, gerados a partir dos valores dos espectros de referência. Os resultados mostram que o algoritmo SAM pode ser aplicado a séries de dados multitemporais de resolução moderada, o que permite eficiente mapeamento de alvo agrícola em escala mesorregional. Dados oficiais de áreas de cana‑de‑açúcar, para as microrregiões paulistas, apresentam boa correlação (r² = 0,8 com os dados obtidos pelo método avaliado. A aplicação do algoritmo SAM mostrou ser útil em análises temporais. As séries temporais de NDVI do sensor SPOT Vegetation podem ser utilizadas para mapeamento da área de cana‑de‑açúcar em baixa resolução.

Simple plasma work-up for a fast chromatographic analysis of homocysteine, cysteine, methionine and aromatic amino acids

Czech Academy of Sciences Publication Activity Database

Hušek, Petr; Matucha, P.; Vránková, A.; Šimek, Petr

2003-01-01

Roč. 789, - (2003), s. 311-322 ISSN 1570-0232 R&D Projects: GA AV ČR IPP1050128; GA MZd NB6708 Institutional research plan: CEZ:AV0Z5007907 Keywords : Homocysteine * cysteine * methionine Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.085, year: 2003

Fabrication and Surface Properties of Composite Films of SAM/Pt/ZnO/SiO 2

KAUST Repository

Yao, Ke Xin; Zeng, Hua Chun

2008-01-01

Through synthetic architecture and functionalization with self-assembled monolayers (SAMs), complex nanocomposite films of SAM/Pt/ZnO/SiO2 have been facilely prepared in this work. The nanostructured films are highly uniform and porous, showing a

Fabrication and tribological properties of self-assembled monolayer of n-alkyltrimethoxysilane on silicon: Effect of SAM alkyl chain length

Science.gov (United States)

Huo, Lixia; Du, Pengcheng; Zhou, Hui; Zhang, Kaifeng; Liu, Peng

2017-02-01

It is well known that the self-assembled organic molecules on a solid surface exhibit the friction-reducing performance. However, the effect of the molecular size of the self-assembled organic molecules has not been established. In the present work, self-assembled monolayers (SAMs) of n-alkyltrimethoxysilanes with different alkyl chain lengths (C6, C12, or C18) were fabricated on silicon substrate. The water contact angles of the SAMs increased from 26.8° of the hydroxylated silicon substrate to near 60° after self-assembly. The atomic force microscopy (AFM) analysis results showed that the mean roughness (Ra) of the SAMs decreased with increasing the alkyl chain length. The tribological properties of the SAMs sliding against Al2O3 ball were evaluated on an UMT-2 tribometer, and the worn surfaces of the samples were analyzed by means of Nano Scratch Tester and surface profilometry. It was found that lowest friction coefficient and smallest width of wear were achieved with the SAMs of C12 alkyl chain (C12-SAM). The superior friction reduction and wear resistance of the SAMs in comparison with the bare silicon substrate are attributed to good adhesion of the self-assembled films to the substrate, especially the C12-SAM with desirable alkyl chain length.

Structural insights into mechanisms of the small RNA methyltransferase HEN1

Energy Technology Data Exchange (ETDEWEB)

Huang, Ying; Ji, Lijuan; Huang, Qichen; Vassylyev, Dmitry G.; Chen, Xuemei; Ma, Jin-Biao; (UAB); (UCR)

2010-02-22

RNA silencing is a conserved regulatory mechanism in fungi, plants and animals that regulates gene expression and defence against viruses and transgenes. Small silencing RNAs of {approx}20-30 nucleotides and their associated effector proteins, the Argonaute family proteins, are the central components in RNA silencing. A subset of small RNAs, such as microRNAs and small interfering RNAs (siRNAs) in plants, Piwi-interacting RNAs in animals and siRNAs in Drosophila, requires an additional crucial step for their maturation; that is, 2'-O-methylation on the 3' terminal nucleotide. A conserved S-adenosyl-L-methionine-dependent RNA methyltransferase, HUA ENHANCER 1 (HEN1), and its homologues are responsible for this specific modification. Here we report the 3.1 {angstrom} crystal structure of full-length HEN1 from Arabidopsis in complex with a 22-nucleotide small RNA duplex and cofactor product S-adenosyl-L-homocysteine. Highly cooperative recognition of the small RNA substrate by multiple RNA binding domains and the methyltransferase domain in HEN1 measures the length of the RNA duplex and determines the substrate specificity. Metal ion coordination by both 2' and 3' hydroxyls on the 3'-terminal nucleotide and four invariant residues in the active site of the methyltransferase domain suggests a novel Mg{sup 2+}-dependent 2'-O-methylation mechanism.

Bringing a Chemical Laboratory Named Sam to Mars on the 2011 Curiosity Rover

Science.gov (United States)

Mahaffy, P. R.; Bleacher, L.; Jones, A.; Conrad, P. G.; Cabane, M.; Webster, C. R.; Atreya, S. A.; Manning, H.

2010-01-01

An important goal of upcoming missions to Mars is to understand if life could have developed there. The task of the Sample Analysis at Mars (SAM) suite of instruments [1] and the other Curiosity investigations [2] is to move us steadily toward that goal with an assessment of the habitability of our neighboring planet through a series of chemical and geological measurements. SAM is designed to search for organic compounds and inorganic volatiles and measure isotope ratios. Other instruments on Curiosity will provide elemental analysis and identify minerals. SAM will analyze both atmospheric samples and gases evolved from powdered rocks that may have formed billions of years ago with Curiosity providing access to interesting sites scouted by orbiting cameras and spectrometers.

A magnesium-induced triplex pre-organizes the SAM-II riboswitch.

Directory of Open Access Journals (Sweden)

Susmita Roy

2017-03-01

Full Text Available Our 13C- and 1H-chemical exchange saturation transfer (CEST experiments previously revealed a dynamic exchange between partially closed and open conformations of the SAM-II riboswitch in the absence of ligand. Here, all-atom structure-based molecular simulations, with the electrostatic effects of Manning counter-ion condensation and explicit magnesium ions are employed to calculate the folding free energy landscape of the SAM-II riboswitch. We use this analysis to predict that magnesium ions remodel the landscape, shifting the equilibrium away from the extended, partially unfolded state towards a compact, pre-organized conformation that resembles the ligand-bound state. Our CEST and SAXS experiments, at different magnesium ion concentrations, quantitatively confirm our simulation results, demonstrating that magnesium ions induce collapse and pre-organization. Agreement between theory and experiment bolsters microscopic interpretation of our simulations, which shows that triplex formation between helix P2b and loop L1 is highly sensitive to magnesium and plays a key role in pre-organization. Pre-organization of the SAM-II riboswitch allows rapid detection of ligand with high selectivity, which is important for biological function.

S-Amlodipine: An Isomer with Difference—Time to Shift from Racemic Amlodipine

Directory of Open Access Journals (Sweden)

Jamshed Dalal

2018-01-01

Full Text Available Calcium channel blockers are among the first-line drugs for treatment of hypertension (HTN. S-amlodipine (S-AM, an S-enantiomer of amlodipine, is available in India and in other countries like China, Korea, Russia, Ukraine, and Nepal. Being clinically researched for nearly two decades, we performed in-depth review of S-AM. This review discusses clinical evidence from total 42 studies (26 randomized controlled trials, 14 observational studies, and 2 meta-analyses corroborating over 7400 patients treated with S-AM. Efficacy and safety of S-AM in HTN in comparison to racemic amlodipine, used as monotherapy and in combination with other antihypertensives, efficacy in angina, and pleiotropic benefits with S-AM, are discussed in this review.

miCLIP-MaPseq, a Substrate Identification Approach for Radical SAM RNA Methylating Enzymes.

Science.gov (United States)

Stojković, Vanja; Chu, Tongyue; Therizols, Gabriel; Weinberg, David E; Fujimori, Danica Galonić

2018-06-13

Although present across bacteria, the large family of radical SAM RNA methylating enzymes is largely uncharacterized. Escherichia coli RlmN, the founding member of the family, methylates an adenosine in 23S rRNA and several tRNAs to yield 2-methyladenosine (m 2 A). However, varied RNA substrate specificity among RlmN enzymes, combined with the ability of certain family members to generate 8-methyladenosine (m 8 A), makes functional predictions across this family challenging. Here, we present a method for unbiased substrate identification that exploits highly efficient, mechanism-based cross-linking between the enzyme and its RNA substrates. Additionally, by determining that the thermostable group II intron reverse transcriptase introduces mismatches at the site of the cross-link, we have identified the precise positions of RNA modification using mismatch profiling. These results illustrate the capability of our method to define enzyme-substrate pairs and determine modification sites of the largely uncharacterized radical SAM RNA methylating enzyme family.

Simulated SAM A-scans on multilayer MEMS components

DEFF Research Database (Denmark)

Janting, Jakob; Petersen, Dirch Hjorth; Greisen, Christoffer

2002-01-01

A spreadsheet program for simulation of Scanning Acoustic Microscopy (SAM) A-scans on multilayer structures has been developed. Using this program, structure variations in samples can be analysed better. Further samples can be prepared to get optimal signal for enhanced failure and materials...

The Journey from Compliancy to Intimate Revolt: A Kristevan Reading of Sam Shepard’s Three Major Plays

Directory of Open Access Journals (Sweden)

Forough Emam

2017-11-01

Full Text Available The study intends to examine three major plays of Sam Shepard –True West, Fool for Love, and A Lie of the Mind– to explore the underlying reasons for the characters’ social transgression in the light of Julia Kristeva’s theory of intimate revolt. Notwithstanding that all the characters feel alienated from reality and other members of society, there is a marked divergence between male and female characters in the approach they adopt to revolt against the societal norms so as to transform their lives. The findings suggest that while men seem less likely to revolt against the rules of patriarchy, it is predominantly women who embark on revolting against the psyche-numbing society to bring jouissance to their once-predetermined meaningless lives. The study comes to the conclusion that by reconnecting with their personal desire and preserving their individuality in a society that hegemonizes its subjects’ identities, women engage in what Kristeva calls ‘intimate revolt’ and become the forces of power and change in the modern world.

Acute Administration of Methionine Affects Performance of Swiss ...

African Journals Online (AJOL)

olayemitoyin

biogenic amines. The effect of methionine on learning and memory in mice was investigated using Morris water maze .... normal brain. This is in a bid to proffer long-term .... A short transfer latency on Day 2 was taken as a ..... age Children.

l-Methionine anti-biofilm activity against Pseudomonas aeruginosa is enhanced by the cystic fibrosis transmembrane conductance regulator potentiator, ivacaftor.

Science.gov (United States)

Cho, Do-Yeon; Lim, Dong-Jin; Mackey, Calvin; Weeks, Christopher G; Peña Garcia, Jaime A; Skinner, Daniel; Grayson, Jessica W; Hill, Harrison S; Alexander, David K; Zhang, Shaoyan; Woodworth, Bradford A

2018-05-01

Biofilms may contribute to refractory chronic rhinosinusitis (CRS), as they lead to antibiotic resistance and failure of effective clinical treatment. l-Methionine is an amino acid with reported biofilm-inhibiting properties. Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator with mild antimicrobial activity via inhibition of bacterial DNA gyrase and topoisomerase IV. The objective of this study was to evaluate whether co-treatment with ivacaftor and l-methionine can reduce the formation of Pseudomonas aeruginosa biofilms. P aeruginosa (PAO-1 strain) biofilms were studied in the presence of l-methionine and/or ivacaftor. For static biofilm assays, PAO-1 was cultured in a 48-well plate for 72 hours with stepwise combinations of these agents. Relative biofilm inhibitions were measured according to optical density of crystal violet stain at 590 nm. Live/dead assays (BacTiter-Glo™ assay, Promega) were imaged with laser scanning confocal microscopy. An agar diffusion test was used to confirm antibacterial effects of the drugs. l-Methionine (0.5 μM) significantly reduced PAO-1 biofilm mass (32.4 ± 18.0%; n = 4; p l-methionine (two-way analysis of variane, p = 0.0415) compared with corresponding concentrations of l-methionine alone. Ivacaftor enhanced the anti-biofilm activity of l-methionine against the PAO-1 strain of P aeruginosa. Further studies evaluating the efficacy of ivacaftor/l-methionine combinations for P aeruginosa sinusitis are planned. © 2018 ARS-AAOA, LLC.

Background of SAM atom-fraction profiles

International Nuclear Information System (INIS)

Ernst, Frank

2017-01-01

Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which is validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition

Background of SAM atom-fraction profiles

Energy Technology Data Exchange (ETDEWEB)

Ernst, Frank

2017-03-15

Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which is validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition.

Effects of methionine supplementation on the expression of protein deposition-related genes in acute heat stress-exposed broilers.

Directory of Open Access Journals (Sweden)

Ana Paula Del Vesco

Full Text Available The objective of this study was to evaluate the effect of heat stress and methionine supplementation on the gene expression of insulin-like growth factor I (IGF-I, growth hormone receptor (GHR, phosphatidylinositol 3-kinase, and regulatory 1 (PI3KR1 in the liver, as well as the expression of the atrogin 1 and cathepsin L2 (CTSL2 genes in the breast muscle of broilers. Broilers from 1-21 and 22-42 days of age were divided into three treatments related to methionine supplementation as follows: without methionine supplementation (MD, recommended level of methionine (DL1, and excess supplementation of methionine (DL2. The animals were either maintained at a thermal comfort temperature or exposed to heat stress (HS (38°C for 24 hours, starting on day 20 or day 41 for experiments 1 and 2, respectively. The heat stress increased the body temperature at both ages. Starter period: The HS animals presented increased plasma creatinine content (P<0.0001 and the highest CTSL2 gene expression (P<0.0001. The methionine supplementation increased the IGF-I (P = 0.0144 and GHR (P = 0.0011 gene expression and decreased the CTSL2 (P = 0.0004 and atrogin 1 (P = 0.0012 gene expression. Grower period: Significant effects for the interaction between supplementation and environment were observed for GHR (P = 0.0252 and CTSL2 (P = 0.0011 gene expression. The highest GHR expression was observed in animals that remained in thermal comfort on the DL2 diet, and the lowest expression occurred in the HS animals fed the MD diet. For CTSL2, the HS animals fed the MD diet presented the highest CTSL2 gene expression, and the lowest expression was observed in the animals maintained at thermal comfort on DL1 and DL2 diets. Only methionine supplementation had effect on atrogin-1 gene expression (P<0.0001, with higher methionine content in the diet lower atrogin-1 gene expression was observed. Our results suggest that heat stress induces greater protein degradation and that

Efficient inhibition of tumor angiogenesis and growth by a synthetic peptide blocking S100A4-methionine aminopeptidase 2 interaction

Directory of Open Access Journals (Sweden)

Takahiro Ochiya

Full Text Available The prometastatic calcium-binding protein, S100A4, is expressed in endothelial cells, and its downregulation markedly suppresses tumor angiogenesis in a xenograft cancer model. Given that endothelial S100A4 can be a molecular target for inhibiting tumor angiogenesis, we addressed here whether synthetic peptide capable of blocking S100A4-effector protein interaction could be a novel antiangiogenic agent. To examine this hypothesis, we focused on the S100A4-binding domain of methionine aminopeptidase 2, an effector protein, which plays a role in endothelial cell growth. Overexpression of the domain in mouse endothelial MSS31 cells reduced DNA synthesis, and the corresponding synthetic peptide (named NBD indeed interacted with S100A4 and inhibited capillary formation in vitro and new blood vessel formation in vivo. Intriguingly, a single intra-tumor administration of the NBD peptide in human prostate cancer xenografts significantly reduced vascularity, resulting in tumor regression. Mechanistically, the NBD peptide enhanced assembly of nonmuscle myosin IIA filaments along with Ser1943 phosphorylation, stimulated formation of focal adhesions without phosphorylation of focal adhesion kinase, and provoked G1/S arrest of the cell cycle. Altogether, the NBD peptide is a potent inhibitor for tumor angiogenesis, and is the first example of an anticancer peptide drug developed on the basis of an endothelial S100A4-targeted strategy.

Reconstruction of Cysteine Biosynthesis Using Engineered Cysteine-Free and Methionine-Free Enzymes

Science.gov (United States)

Wang, Kendrick; Fujishima, Kosuke; Abe, Nozomi; Nakahigashi, Kenji; Endy, Drew; Rothschild, Lynn J.

2016-01-01

Ten of the proteinogenic amino acids can be generated abiotically while the remaining thirteen require biology for their synthesis. Paradoxically, the biosynthesis pathways observed in nature require enzymes that are made with the amino acids they produce. For example, Escherichia coli produces cysteine from serine via two enzymes that contain cysteine. Here, we substituted alternate amino acids for cysteine and also methionine, which is biosynthesized from cysteine, in serine acetyl transferase (CysE) and O-acetylserine sulfhydrylase (CysM). CysE function was rescued by cysteine-and-methionine-free enzymes and CysM function was rescued by cysteine-free enzymes. Structural modeling suggests that methionine stabilizes CysM and is present in the active site of CysM. Cysteine is not conserved among CysE and CysM protein orthologs, suggesting that cysteine is not functionally important for its own synthesis. Engineering biosynthetic enzymes that lack the amino acids being synthesized provides insights into the evolution of amino acid biosynthesis and pathways for bioengineering.

Effect of methionine supplementation in chicken feed on the quality and shelf life of fresh poultry meat.

Science.gov (United States)

Albrecht, Antonia; Herbert, Ulrike; Miskel, Dennis; Heinemann, Celine; Braun, Carina; Dohlen, Sophia; Zeitz, Johanna O; Eder, Klaus; Saremi, Behnam; Kreyenschmidt, Judith

2017-08-01

The aim of this study was to investigate the influence of different methionine sources and concentrations on the quality and spoilage process of broiler meat. The trial was comprised of 7 treatment groups: one basal group (suboptimal in Methionine+Cysteine; i.e., 0.89, 0.74, 0.69% in DM SID Met+Cys in starter, grower, and finisher diets, respectively) and 3 doses (0.10, 0.25, and 0.40%) of either DL-Methionine (DLM) or DL-2-hydroxy-4-methylthio butanoic acid (DL-HMTBA) on an equimolar basis of the DLM-supplemented groups. The broilers were fed the diets for 35 d, then slaughtered and processed. The filets were aerobically packed and stored under temperature controlled conditions at 4°C. Meat quality investigations were comprised of microbial investigations (total viable count and Pseudomonas spp.), pH and drip loss measurements of the filets. The shelf life of the meat samples was determined based on sensory parameters. After slaughtering, all supplemented meat samples showed a high quality, whereby no differences between the 2 methionine sources could be detected for the microbial load, pH, and drip loss. In comparison to the control group, the supplemented samples showed a higher sensory quality, characterized by a fresh smell and fresh red color. Methionine supplementation had a significant influence on meat quality parameters during storage. The microbial load, pH and drip loss of the chicken filets were positively correlated to the methionine concentration. Additionally, the microbial load at the end of storage was positively correlated to pH and drip loss values. Nevertheless, the microbial parameters were in a normal range and the positive correlation to methionine concentration did not affect the sensory shelf life. The mean sensory shelf life of the broiler filets varied between 7 to 9 d. During storage, no difference in the development of sensory parameters was observed between the supplemented groups, while the spoilage process of the basal group

21 CFR 172.372 - N-Acetyl-L-methionine.

Science.gov (United States)

2010-04-01

... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.372 N-Acetyl-L-methionine. The food additive N-acetyl-L...

Diorganotin(IV) Complexes with Methionine Methyl Ester. Equilibria ...

African Journals Online (AJOL)

IV) (DBT) and diphenyltin(IV) (DPT) was investigated at 25 °C and 0.1 mol dm–3 ionic strength in water for dimethyltin(IV) and in 50 % dioxane–water mixture for dibutyltin(IV) and diphenyltin(IV). Methionine methyl ester forms1:1 and 1:2 ...

Development of the criticality capability for the SAM-CE Monte Carlo System

International Nuclear Information System (INIS)

Lichtenstein, H.; Troubetzkoy, E.; Steinberg, H.; Cohen, M.O.

1979-04-01

A criticality capabilty has been developed and implemented in the SAM-CE Monte Carlo system. The data processing component, SAM-X, preserves, to any required accuracy, the data quality inherent in the ENDF/B library. The generated data is Doppler-broadened and includes (where applicable) probability tables for the unresolved resonance range, and thermal-scattering law data. Curves of several total and partial cross sections are generated and displayed. The Monte Carlo component, SAM-F, includes several eigenvalue estimators and variance reduction schemes. Stratification was found to effect significant improvement in calculational efficiency, but the usefulness of importance sampling is marginal in criticality problems. The entire system has been installed at BNL, for the analysis of TRX benchmarks. The TRX-1 and TRX-2 cell calculations have been performed, with estimated eigenvalues of 1.1751 +- 0.0016 and 1.1605 +- .0015, respectively. These results are shown to be statistically consistent with other sources

Role of Helicobacter pylori methionine sulfoxide reductase in urease maturation

Science.gov (United States)

Kuhns, Lisa G.; Mahawar, Manish; Sharp, Joshua S.; Benoit, Stéphane; Maier, Robert J.

2014-01-01

The persistence of the gastric pathogen Helicobacter pylori is due in part to urease and Msr (methionine sulfoxide reductase). Upon exposure to relatively mild (21% partial pressure of O2) oxidative stress, a Δmsr mutant showed both decreased urease specific activity in cell-free extracts and decreased nickel associated with the partially purified urease fraction as compared with the parent strain, yet urease apoprotein levels were the same for the Δmsr and wild-type extracts. Urease activity of the Δmsr mutant was not significantly different from the wild-type upon non-stress microaerobic incubation of strains. Urease maturation occurs through nickel mobilization via a suite of known accessory proteins, one being the GTPase UreG. Treatment of UreG with H2O2 resulted in oxidation of MS-identified methionine residues and loss of up to 70% of its GTPase activity. Incubation of pure H2O2-treated UreG with Msr led to reductive repair of nine methionine residues and recovery of up to full enzyme activity. Binding of Msr to both oxidized and non-oxidized UreG was observed by cross-linking. Therefore we conclude Msr aids the survival of H. pylori in part by ensuring continual UreG-mediated urease maturation under stress conditions. PMID:23181726

Retrospective evaluation of methionine intoxication associated with urinary acidifying products in dogs: 1,525 cases (2001-2012).

Science.gov (United States)

Hickey, Mara C; Son, Tolina T; Wismer, Tina

2015-01-01

To describe the signalment, clinical findings, timing of signs, outcome, and prognosis in a population of dogs exposed to methionine through the ingestion of urine acidifying products. Retrospective observational study from January 1, 2001 to December 31, 2012. Animal Poison Control Center. A total of 1,197 case calls yielding 1,525 dogs identified with presumed methionine ingestion. None. Records of dogs with presumptive methionine ingestion were reviewed from the American Society for the Prevention of Cruelty to Animals Animal Poison Control Center database. Ingested methionine doses ranged from 3.9 mg/kg to 23,462 mg/kg. Clinical signs developed in 47% of dogs. The most common clinical signs were gastrointestinal (GI) and neurologic. The mean onset of GI signs was 2.8 hours following ingestion. The mean onset of neurologic signs was 6.8 hours following ingestion. GI signs were identified with ingested doses ≥22.5 mg/kg. Vomiting was the most common GI sign. Neurologic signs were identified with ingested doses ≥94.6 mg/kg. Ataxia was the most common neurologic sign. Resolution of clinical signs occurred within 48 hours of ingestion, and no fatalities were reported. Prognosis for dogs with methionine intoxication is excellent. Vomiting and ataxia were the most common clinical signs associated with methionine toxicosis. © Veterinary Emergency and Critical Care Society 2015.

Transgenic tobacco plants having a higher level of methionine are more sensitive to oxidative stress.

Science.gov (United States)

Hacham, Yael; Matityahu, Ifat; Amir, Rachel

2017-07-01

Methionine is an essential amino acid the low level of which limits the nutritional quality of plants. We formerly produced transgenic tobacco (Nicotiana tabacum) plants overexpressing CYSTATHIONE γ-SYNTHASE (CGS) (FA plants), methionine's main regulatory enzyme. These plants accumulate significantly higher levels of methionine compared with wild-type (WT) plants. The aim of this study was to gain more knowledge about the effect of higher methionine content on the metabolic profile of vegetative tissue and on the morphological and physiological phenotypes. FA plants exhibit slightly reduced growth, and metabolic profiling analysis shows that they have higher contents of stress-related metabolites. Despite this, FA plants were more sensitive to short- and long-term oxidative stresses. In addition, compared with WT plants and transgenic plants expressing an empty vector, the primary metabolic profile of FA was altered less during oxidative stress. Based on morphological and metabolic phenotypes, we strongly proposed that FA plants having higher levels of methionine suffer from stress under non-stress conditions. This might be one of the reasons for their lesser ability to cope with oxidative stress when it appeared. The observation that their metabolic profiling is much less responsive to stress compared with control plants indicates that the delta changes in metabolite contents between non-stress and stress conditions is important for enabling the plants to cope with stress conditions. © 2017 Scandinavian Plant Physiology Society.

Partitioning of L-methionine in aqueous two-phase systems containing poly(propylene glycol) and sodium phosphate salts

Energy Technology Data Exchange (ETDEWEB)

Salabat, Alireza, E-mail: a-salabat@araku.ac.ir [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of); Moghadam, Somayeh Tiani [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Jamehbozorg, Bahman [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of)

2011-10-15

Highlights: > Thermodynamics parameters for partitioning of L-methionine in ATPS. > Investigation of different effects on partition coefficient of the amino acid. > Propose the best condition for L-methionine partitioning. - Abstract: The partitioning behavior of L-methionine has been studied in aqueous two-phase systems of (poly(propylene glycol) + sodium phosphate salts + H{sub 2}O) at different temperatures. The salts used were sodium di-hydrogen phosphate (NaH{sub 2}PO{sub 4}), di-sodium hydrogen phosphate (Na{sub 2}HPO{sub 4}) and tri-sodium phosphate (Na{sub 3}PO{sub 4}). The effects of tie line length, salt type, and temperature on the partition coefficient of this amino acid have been studied. In addition, thermodynamic parameters ({Delta}H{sup o}, {Delta}S{sup o} and {Delta}G{sup o}) as a function of temperature were calculated. The results showed that increasing tie line length led to decreasing of the partition coefficient. We also showed that the partition coefficients of the amino acid in the systems containing Na{sub 3}PO{sub 4} are greater than the other two salts. Moreover, it is verified that increasing temperature led to decreasing the partition coefficient. The experimental partition coefficient data are correlated using a modified virial-type model.

Dopamine D2 receptor function is compromised in the brain of the methionine sulfoxide reductase A knockout mouse

OpenAIRE

Oien, Derek B.; Ortiz, Andrea N.; Rittel, Alexander G.; Dobrowsky, Rick T.; Johnson, Michael A.; Levant, Beth; Fowler, Stephen C.; Moskovitz, Jackob

2010-01-01

Previous research suggests that brain oxidative stress and altered rodent locomotor behavior are linked. We observed bio-behavioral changes in methionine sulfoxide reductase A knockout mice associated with abnormal dopamine signaling. Compromised ability of these knockout mice to reduce methionine sulfoxide enhances accumulation of sulfoxides in proteins. We examined the dopamine D2-receptor function and expression, which has an atypical arrangement and quantity of methionine residues. Indeed...

Platinum(II) complexes with steroidal esters of L-methionine and L-histidine: Synthesis, characterization and cytotoxic activity

Czech Academy of Sciences Publication Activity Database

Kvasnica, Miroslav; Buděšínský, Miloš; Swaczynová, Jana; Pouzar, Vladimír; Kohout, Ladislav

2008-01-01

Roč. 16, č. 7 (2008), s. 3704-3713 ISSN 0968-0896 R&D Projects: GA AV ČR KAN200200651 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50380511 Keywords : steroids * platinum * L-histidin * L-methionin Subject RIV: CC - Organic Chemistry Impact factor: 3.075, year: 2008

Mutant form C115H of Clostridium sporogenes methionine γ-lyase efficiently cleaves S-Alk(en)yl-l-cysteine sulfoxides to antibacterial thiosulfinates.

Science.gov (United States)

Kulikova, Vitalia V; Anufrieva, Natalya V; Revtovich, Svetlana V; Chernov, Alexander S; Telegin, Georgii B; Morozova, Elena A; Demidkina, Tatyana V

2016-10-01

Pyridoxal 5'-phosphate-dependent methionine γ-lyase (MGL) catalyzes the β-elimination reaction of S-alk(en)yl-l-cysteine sulfoxides to thiosulfinates, which possess antimicrobial activity. Partial inactivation of the enzyme in the course of the reaction occurs due to oxidation of active site cysteine 115 conserved in bacterial MGLs. In this work, the C115H mutant form of Clostridium sporogenes MGL was prepared and the steady-state kinetic parameters of the enzyme were determined. The substitution results in an increase in the catalytic efficiency of the mutant form towards S-substituted l-cysteine sulfoxides compared to the wild type enzyme. We used a sulfoxide/enzyme system to generate antibacterial activity in situ. Two-component systems composed of the mutant enzyme and three S-substituted l-cysteine sulfoxides were demonstrated to be effective against Gram-positive and Gram-negative bacteria and three clinical isolates from mice. © 2016 IUBMB Life, 68(10):830-835, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

The SAM, not the electrodes, dominates charge transport in metal-monolayer//Ga2O3/gallium-indium eutectic junctions.

Science.gov (United States)

Reus, William F; Thuo, Martin M; Shapiro, Nathan D; Nijhuis, Christian A; Whitesides, George M

2012-06-26

The liquid-metal eutectic of gallium and indium (EGaIn) is a useful electrode for making soft electrical contacts to self-assembled monolayers (SAMs). This electrode has, however, one feature whose effect on charge transport has been incompletely understood: a thin (approximately 0.7 nm) film-consisting primarily of Ga(2)O(3)-that covers its surface when in contact with air. SAMs that rectify current have been measured using this electrode in Ag(TS)-SAM//Ga(2)O(3)/EGaIn (where Ag(TS) = template-stripped Ag surface) junctions. This paper organizes evidence, both published and unpublished, showing that the molecular structure of the SAM (specifically, the presence of an accessible molecular orbital asymmetrically located within the SAM), not the difference between the electrodes or the characteristics of the Ga(2)O(3) film, causes the observed rectification. By examining and ruling out potential mechanisms of rectification that rely either on the Ga(2)O(3) film or on the asymmetry of the electrodes, this paper demonstrates that the structure of the SAM dominates charge transport through Ag(TS)-SAM//Ga(2)O(3)/EGaIn junctions, and that the electrical characteristics of the Ga(2)O(3) film have a negligible effect on these measurements.

Acceleration of selenium volatilization in seleniferous agricultural drainage sediments amended with methionine and casein

Energy Technology Data Exchange (ETDEWEB)

Banuelos, G.S. [USDA-ARS, Water Management Research Laboratory, Parlier, CA 93648 (United States)], E-mail: gbanuelos@fresno.ars.usda.gov; Lin, Z.-Q. [Department of Biological Sciences and Environmental Sciences Program, Southern Illinois University Edwardsville, Edwardsville, IL 62026-1651 (United States)

2007-12-15