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Sample records for acid mononucleotide adenylyltransferase

  1. Crystal structure of nicotinic acid mononucleotide adenylyltransferase from Staphyloccocus aureus: structural basis for NaAD interaction in functional dimer.

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    Han, Seungil; Forman, Michael D; Loulakis, Pat; Rosner, Michelle H; Xie, Zhi; Wang, Hong; Danley, Dennis E; Yuan, Wei; Schafer, John; Xu, Zuoyu

    2006-07-21

    Bacterial nicotinic acid mononucleotide adenylyltransferase (NaMNAT; EC 2.7.7.18) encoded by the nadD gene, is essential for cell survival and is thus an attractive target for developing new antibacterial agents. The NaMNAT catalyzes the transfer of an adenylyl group of ATP to nicotinic acid mononucleotide (NaMN) to form nicotinic acid dinucleotide (NaAD). Two independently derived, high-resolution structures of Staphylococcus aureus NaMNAT-NaAD complexes establish the conserved features of the core dinucleotide-binding fold with other adenylyltransferases from bacteria to human despite a limited sequence conservation. The crystal structures reveal that the nicotinate carboxylates of NaAD are recognized by interaction with the main-chain amides of Thr85 and Tyr117, a positive helix dipole and two bridged-water molecules. Unlike other bacterial adenylyltransferases, where a partially conserved histidine residue interacts with the nicotinate ring, the Leu44 side-chain interacts with the nicotinate ring by van der Waals contact. Importantly, the S. aureus NaMNAT represents a distinct adenylyltransferase subfamily identifiable in part by common features of dimerization and substrate recognition in the loop connecting beta5 to beta6 (residues 132-146) and the additional beta6 strand. The unique beta6 strand helps orient the residues in the loop connecting beta5 to beta6 for substrate/product recognition and allows the beta7 strand structural flexibility to make key dimer interface interactions. Taken together, these structural results provide a molecular basis for understanding the coupled activity and recognition specificity for S. aureus NaMNAT and for rational design of selective inhibitors.

  2. YCL047C/POF1 is a novel nicotinamide mononucleotide adenylyltransferase (NMNAT) in Saccharomyces cerevisiae.

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    Kato, Michiko; Lin, Su-Ju

    2014-05-30

    NAD(+) is an essential metabolic cofactor involved in various cellular biochemical processes. Nicotinamide riboside (NR) is an endogenously produced key pyridine metabolite that plays important roles in the maintenance of NAD(+) pool. Using a NR-specific cell-based screen, we identified mutants that exhibit altered NR release phenotype. Yeast cells lacking the ORF YCL047C/POF1 release considerably more NR compared with wild type, suggesting that POF1 plays an important role in NR/NAD(+) metabolism. The amino acid sequence of Pof1 indicates that it is a putative nicotinamide mononucleotide adenylyltransferase (NMNAT). Unlike other yeast NMNATs, Pof1 exhibits NMN-specific adenylyltransferase activity. Deletion of POF1 significantly lowers NAD(+) levels and decreases the efficiency of NR utilization, resistance to oxidative stress, and NR-induced life span extension. We also show that NR is constantly produced by multiple nucleotidases and that the intracellular NR pools are likely to be compartmentalized, which contributes to the regulation of NAD(+) homeostasis. Our findings may contribute to the understanding of the molecular basis and regulation of NAD(+) metabolism in higher eukaryotes.

  3. Analysis of Escherichia coli nicotinate mononucleotide adenylyltransferase mutants in vivo and in vitro

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    Rydén-Aulin Monica

    2005-09-01

    Full Text Available Abstract Background Adenylation of nicotinate mononucleotide to nicotinate adenine dinucleotide is the penultimate step in NAD+ synthesis. In Escherichia coli, the enzyme nicotinate mononucleotide adenylyltransferase is encoded by the nadD gene. We have earlier made an initial characterization in vivo of two mutant enzymes, NadD72 and NadD74. Strains with either mutation have decreased intracellular levels of NAD+, especially for one of the alleles, nadD72. Results In this study these two mutant proteins have been further characterized together with ten new mutant variants. Of the, in total, twelve mutations four are in a conserved motif in the C-terminus and eight are in the active site. We have tested the activity of the enzymes in vitro and their effect on the growth phenotype in vivo. There is a very good correlation between the two data sets. Conclusion The mutations in the C-terminus did not reveal any function for the conserved motif. On the other hand, our data has lead us to assign amino acid residues His-19, Arg-46 and Asp-109 to the active site. We have also shown that the nadD gene is essential for growth in E. coli.

  4. Isoform-specific targeting and interaction domains in human nicotinamide mononucleotide adenylyltransferases.

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    Lau, Corinna; Dölle, Christian; Gossmann, Toni I; Agledal, Line; Niere, Marc; Ziegler, Mathias

    2010-06-11

    Several important signaling pathways require NAD as substrate, thereby leading to significant consumption of the molecule. Because NAD is also an essential redox carrier, its continuous resynthesis is vital. In higher eukaryotes, maintenance of compartmentalized NAD pools is critical, but so far rather little is known about the regulation and subcellular distribution of NAD biosynthetic enzymes. The key step in NAD biosynthesis is the formation of the dinucleotide by nicotinamide/nicotinic acid mononucleotide adenylyltransferases (NMNATs). The three human isoforms were localized to the nucleus, the Golgi complex, and mitochondria. Here, we show that their genes contain unique exons that encode isoform-specific domains to mediate subcellular targeting and post-translational modifications. These domains are dispensable for catalytic activity, consistent with their absence from NMNATs of lower organisms. We further demonstrate that the Golgi-associated NMNAT is palmitoylated at two adjacent cysteine residues of its isoform-specific domain and thereby anchored at the cytoplasmic surface, a potential mechanism to regulate the cytosolic NAD pool. Insertion of unique domains thus provides a yet unrecognized enzyme targeting mode, which has also been adapted to modulate subcellular NAD supply.

  5. Nicotinamide mononucleotide adenylyltransferase 1 gene NMNAT1 regulates neuronal dendrite and axon morphogenesis in vitro

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong; ZHANG Jing-yu; YANGZi-chao; LIU Ming; GANG Bao-zhi; ZHAO Qing-jie

    2011-01-01

    Background Wallerian degeneration is a self-destructive process of axonal degeneration that occurs after an axonal injury or during neurodegenerative disorders such as Parkinson's or Alzheimer's disease.Recent studies have found that the activity of the nicotinamide adenine dinucleotide (NAD) synthase enzyme,nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) can affect the rate of Wallerian degeneration in mice and drosophila.NMNAT1 protects neurons and axons from degeneration.However,the role of NMNAT1 in neurons of central nervous system is still not well understood.Methods We set up the culture of primary mouse neurons in vitro and manipulated the expression level of NMNAT1 by RNA interference and gene overexpression methods.Using electroporation transfection we can up-regulate or down-regulate NMNAT1 in cultured mouse dendrites and axons and study the neuronal morphogenesis by immunocytochemistry.In all functional assays,FK-866 (CAS 658084-64-1),a highly specific non-competitive inhibitor of nicotinamide phosphoribosyltransferase was used as a pharmacological and positive control.Results Our results showed that knocking down NMNAT1 by RNA interference led to a marked decrease in dendrite outgrowth and branching and a significant decrease in axon growth and branching in developing cortical neurons in vitro.Conclusions These findings reveal a novel role for NMNAT1 in the morphogenesis of developing cortical neurons,which indicate that the loss of function of NMNAT1 may contribute to different neurodegenerative disorders in central nervous system.

  6. Nicotinamide mononucleotide adenylyltransferase 2 (Nmnat2 regulates axon integrity in the mouse embryo.

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    Amy N Hicks

    Full Text Available Using transposon-mediated gene-trap mutagenesis, we have generated a novel mouse mutant termed Blad (Bloated Bladder. Homozygous mutant mice die perinatally showing a greatly distended bladder, underdeveloped diaphragm and a reduction in total skeletal muscle mass. Wild type and heterozygote mice appear normal. Using PCR, we identified a transposon insertion site in the first intron of Nmnat2 (Nicotinamide mononucleotide adenyltransferase 2. Nmnat2 is expressed predominantly in the brain and nervous system and has been linked to the survival of axons. Expression of this gene is undetectable in Nmnat2(blad/blad mutants. Examination of the brains of E18.5 Nmnat2(blad/blad mutant embryos did not reveal any obvious morphological changes. In contrast, E18.5 Nmnat2(blad/blad homozygotes showed an approximate 60% reduction of spinal motoneurons in the lumbar region and a more than 80% reduction in the sensory neurons of the dorsal root ganglion (DRG. In addition, facial motoneuron numbers were severely reduced, and there was virtually a complete absence of axons in the hind limb. Our observations suggest that during embryogenesis, Nmnat2 plays an important role in axonal growth or maintenance. It appears that in the absence of Nmnat2, major target organs and tissues (e.g., muscle are not functionally innervated resulting in perinatal lethality. In addition, neither Nmnat1 nor 3 can compensate for the loss of Nmnat2. Whilst there have been recent suggestions that Nmnat2 may be an endogenous modulator of axon integrity, this work represents the first in vivo study demonstrating that Nmnat2 is involved in axon development or survival in a mammal.

  7. Role of key residues at the flavin mononucleotide (FMN):adenylyltransferase catalytic site of the bifunctional riboflavin kinase/flavin adenine dinucleotide (FAD) Synthetase from Corynebacterium ammoniagenes.

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    Serrano, Ana; Frago, Susana; Velázquez-Campoy, Adrián; Medina, Milagros

    2012-11-08

    In mammals and in yeast the conversion of Riboflavin (RF) into flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) is catalysed by the sequential action of two enzymes: an ATP:riboflavin kinase (RFK) and an ATP:FMN adenylyltransferase (FMNAT). However, most prokaryotes depend on a single bifunctional enzyme, FAD synthetase (FADS), which folds into two modules: the C-terminal associated with RFK activity and the N-terminal associated with FMNAT activity. Sequence and structural analysis suggest that the 28-HxGH-31, 123-Gx(D/N)-125 and 161-xxSSTxxR-168 motifs from FADS must be involved in ATP stabilisation for the adenylylation of FMN, as well as in FAD stabilisation for FAD phyrophosphorolysis. Mutants were produced at these motifs in the Corynebacterium ammoniagenes FADS (CaFADS). Their effects on the kinetic parameters of CaFADS activities (RFK, FMNAT and FAD pyrophosphorilase), and on substrates and product binding properties indicate that H28, H31, N125 and S164 contribute to the geometry of the catalytically competent complexes at the FMNAT-module of CaFADS.

  8. Role of Key Residues at the Flavin Mononucleotide (FMN:Adenylyltransferase Catalytic Site of the Bifunctional Riboflavin Kinase/Flavin Adenine Dinucleotide (FAD  Synthetase from Corynebacterium ammoniagenes

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    Susana Frago

    2012-11-01

    Full Text Available In mammals and in yeast the conversion of Riboflavin (RF into flavin mononucleotide (FMN and flavin adenine dinucleotide (FAD is catalysed by the sequential action of two enzymes: an ATP:riboflavin kinase (RFK and an ATP:FMN adenylyltransferase (FMNAT. However, most prokaryotes depend on a single bifunctional enzyme, FAD synthetase (FADS, which folds into two modules: the C-terminal associated with RFK activity and the N-terminal associated with FMNAT activity. Sequence and structural analysis suggest that the 28-HxGH-31, 123-Gx(D/N-125 and 161-xxSSTxxR-168 motifs from FADS must be involved in ATP stabilisation for the adenylylation of FMN, as well as in FAD stabilisation for FAD phyrophosphorolysis. Mutants were produced at these motifs in the Corynebacterium ammoniagenes FADS (CaFADS. Their effects on the kinetic parameters of CaFADS activities (RFK, FMNAT and FAD pyrophosphorilase, and on substrates and product binding properties indicate that H28, H31, N125 and S164 contribute to the geometry of the catalytically competent complexes at the FMNAT-module of CaFADS.

  9. Caffeic Acid Inhibits the Formation of 7-Carboxyheptyl Radicals from Oleic Acid under Flavin Mononucleotide Photosensitization by Scavenging Singlet Oxygen and Quenching the Excited State of Flavin Mononucleotide

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    Marie Asano

    2014-08-01

    Full Text Available We examined the effects of caffeic acid (CA and related compounds on 7-carboxyheptyl radical formation. This analysis was performed using a standard D2O reaction mixture containing 4.3 mM oleic acid, 25 μM flavin mononucleotide (FMN, 160 mM phosphate buffer (pH 7.4, 10 mM cholic acid, 100 mM α-(4-pyridyl-1-oxide-N-tert-butylnitrone, and 1 mM Fe(SO42(NH42 during irradiation with 7.8 J/cm2 at 436 nm. 7-Carboxyheptyl radical formation was inhibited by CA, catechol, gallic acid, chlorogenic acid, ferulic acid, noradrenalin, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 4-hydroxybenzoic acid. Quinic acid, benzoic acid, and p-anisic acid had no effect on radical formation. These results suggest that a phenol moiety is essential for these inhibitory effects. The fluorescence intensity of FMN decreased by 69% ± 2% after CA addition, suggesting that CA quenches the singlet excited state of FMN. When 1 mM CA was added to a standard reaction mixture containing 25 μM FMN, 140 mM phosphate buffer (pH 7.4, and 10 mM 4-oxo-2,2,6,6-tetramethylpiperidine, the electron spin resonance signal of 4-oxo-2,2,6,6-tetramethylpiperidinooxy disappeared. This finding suggests that singlet oxygen was scavenged completely by CA. Therefore, CA appears to inhibit 7-carboxyheptyl radical formation by scavenging singlet oxygen and quenching the excited state of FMN.

  10. The NMN/NaMN adenylyltransferase (NMNAT) protein family.

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    Lau, Corinna; Niere, Marc; Ziegler, Mathias

    2009-01-01

    NAD biosynthesis has become of considerable interest owing to the important signaling functions of the pyridine nucleotides which have been recognized over the past years. The formation of the dinucleotides from ATP and the mononucleotide of niacin (either nicotinamide or nicotinic acid) constitute the critical step in NAD generation which is catalyzed by NMN/NaMN adenylyltransferases, NMNATs. Recent research has established the molecular, catalytic and structural properties of NMNATs from many organisms. Detailed studies, particularly of the human NMNATs, have revealed distinct isoform-specific characteristics relating to enzyme kinetics and substrate specificity, oligomeric assembly as well as subcellular and tissue distribution. Moreover, direct functional relationships between NMNATs and major NAD-mediated signaling processes have been discovered suggesting that at least some of these proteins might play more than just an enzymatic role. Several investigations have also pointed to a critical role of NMNATs in pathological states such as cancer and neurodegeneration. This article intends to provide a comprehensive overview of the family of NMNATs and highlights some of the recently identified functional roles of these enzymes.

  11. Identification of Isn1 and Sdt1 as glucose- and vitamin-regulated nicotinamide mononucleotide and nicotinic acid mononucleotide [corrected] 5'-nucleotidases responsible for production of nicotinamide riboside and nicotinic acid riboside.

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    Bogan, Katrina L; Evans, Charles; Belenky, Peter; Song, Peng; Burant, Charles F; Kennedy, Robert; Brenner, Charles

    2009-12-11

    Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD(+), which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast. Secreted nicotinamide riboside was detected with a biological assay, and intracellular levels of nicotinamide riboside, nicotinic acid riboside, and other NAD(+) metabolites were determined by a liquid chromatography-mass spectrometry method. A biochemical genomic screen indicated that three yeast enzymes possess nicotinamide mononucleotide 5'-nucleotidase activity in vitro. Metabolic profiling of knock-out mutants established that Isn1 and Sdt1 are responsible for production of nicotinamide riboside and nicotinic acid riboside in cells. Isn1, initially classified as an IMP-specific 5'-nucleotidase, and Sdt1, initially classified as a pyrimidine 5'-nucleotidase, are additionally responsible for dephosphorylation of pyridine mononucleotides. Sdt1 overexpression is growth-inhibitory to cells in a manner that depends on its active site and correlates with reduced cellular NAD(+). Expression of Isn1 protein is positively regulated by the availability of nicotinic acid and glucose. These results reveal unanticipated and highly regulated steps in NAD(+) metabolism.

  12. Identification of the glutamine synthetase adenylyltransferase of Azospirillum brasilense.

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    Van Dommelen, Anne; Spaepen, Stijn; Vanderleyden, Jozef

    2009-04-01

    Glutamine synthetase, a key enzyme in nitrogen metabolism of both prokaryotes and eukaryotes, is strictly regulated. One means of regulation is the modulation of activity through adenylylation catalyzed by adenylyltransferases. Using PCR primers based on conserved sequences in glutamine synthetase adenylyltransferases, we amplified part of the glnE gene of Azospirillum brasilense Sp7. The complete glnE sequence of A. brasilense Sp245 was retrieved from the draft genome sequence of this organism (http://genomics.ornl.gov/research/azo/). Adenylyltransferase is a bifunctional enzyme consisting of an N-terminal domain responsible for deadenylylation activity and a C-terminal domain responsible for adenylylation activity. Both domains are partially homologous to each other. Residues important for catalytic activity were present in the deduced amino acid sequence of the A. brasilense Sp245 glnE sequence. A glnE mutant was constructed in A. brasilense Sp7 by inserting a kanamycin resistance cassette between the two active domains of the enzyme. The resulting mutant was unable to adenylylate the glutamine synthetase enzyme and was impaired in growth when shifted from nitrogen-poor to nitrogen-rich medium.

  13. Identification of Isn1 and Sdt1 as Glucose- and Vitamin-regulated Nicotinamide Mononucleotide and Nicotinic Acid Mononucleotide 5′-Nucleotidases Responsible for Production of Nicotinamide Riboside and Nicotinic Acid Riboside*

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    Bogan, Katrina L.; Evans, Charles; Belenky, Peter; Song, Peng; Burant, Charles F.; Kennedy, Robert; Brenner, Charles

    2009-01-01

    Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD+, which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast...

  14. Kinetic mechanism of streptomycin adenylyltransferase from a recombinant Escherichia coli.

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    Jana, Snehasis; Deb, J K

    2005-04-01

    Bacterial resistance to the aminoglycoside antibiotics is manifested primarily by enzymic modification of these drugs. One important mechanism of streptomycin modification is through ATP-dependent O-adenylation, catalyzed by streptomycin adenylyltransferase. Initial velocity patterns deduced from steady state kinetics indicate a sequential mechanism. Dead-end inhibition by tobramycin and neomycin is non-competitive versus streptomycin and uncompetitive versus ATP, indicative of ordered substrate binding where ATP binds first and then streptomycin. These results surmise that streptomycin adenylyltransferase follows an ordered, sequential kinetic mechanism in which one substrate (ATP) binds prior to the antibiotic and pyrophosphate is released prior to formation of AMP-streptomycin.

  15. Virtual screening of selective inhibitors of phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis

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    Podshivalov, D. D.; Timofeev, V. I.; Sidorov-Biryukov, D. D.; Kuranova, I. P.

    2017-05-01

    Bacterial phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis (PPAT Mt) is a convenient target protein for the directed search for selective inhibitors as potent antituberculosis drugs. Four compounds suitable for the detailed investigation of their interactions with PPAT Mt were found by virtual screening. The active-site region of the enzyme was chosen as the ligand-binding site. The positions of the ligands found by the docking were refined by molecular dynamics simulation. The nearest environment of the ligands, the positions of which in the active site of the enzyme were found in a computational experiment, was analyzed. The compounds under consideration were shown to directly interact with functionally important active-site amino-acid residues and block access of substrates to the active site. Therefore, these compounds can be used for the design of selective inhibitors of PPAT Mt as potent antituberculosis drugs.

  16. Initial-rate kinetics of human NMN-adenylyltransferases: substrate and metal ion specificity, inhibition by products and multisubstrate analogues, and isozyme contributions to NAD+ biosynthesis.

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    Sorci, Leonardo; Cimadamore, Flavio; Scotti, Stefania; Petrelli, Riccardo; Cappellacci, Loredana; Franchetti, Palmarisa; Orsomando, Giuseppe; Magni, Giulio

    2007-04-24

    Initial-rate and product inhibition studies revealed distinctive ordered ternary complex kinetic mechanisms, substrate specificities, and metal ion preferences for the three isozymes of human nicotinamide mononucleotide adenylyl-transferase (NMNAT, EC 2.7.7.1). ATP binds before NMN with nuclear isozyme NMNAT1 and Golgi apparatus NMNAT2, but the opposite order is observed with the mitochondrial isozyme NMNAT3. Only the latter utilizes ITP efficiently in place of ATP, and while NMNH conversion to NADH by NMNAT1 and NMNAT3 occurs at similar rates, conversion by NMNAT2 is much slower. These isozymes can also be discriminated by their action on tiazofurin monophosphate (TrMP), a metabolite of the antineoplastic prodrug tiazofurin. Our finding that TrMP is only a substrate with NMNAT1 and NMNAT3 reveals for the first time an organelle selectivity in the metabolism of this important drug. In search of additional ways to discriminate these isozymes, we synthesized and tested the P1-(nicotinamide/nicotinate-riboside-5')-Pn-(adenosine-5') dinucleotides Np3AD, Np4AD, and Nap4AD. In addition to being highly effective inhibitors, these multisubstrate geometric inhibitors gave inhibition patterns that are consistent with the aforementioned isozyme differences in substrate binding order. Distinctive differences in their substrate specificity and metal ion selectivity also permitted us to quantify individual isozyme contributions to NAD+ formation in human cell extracts.

  17. Yeast Interacting Proteins Database: YNL189W, YLR328W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available nvolved in pathways of NAD biosynthesis, including the de novo, NAD(+) salvage, and nicotinamide riboside sa... Nicotinic acid mononucleotide adenylyltransferase, involved in pathways of NAD biosynthesis, including the de novo, NAD(+) salvage,

  18. Yeast Interacting Proteins Database: YGR010W, YLR328W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available 1 Nicotinic acid mononucleotide adenylyltransferase, involved in pathways of NAD biosynthesis, including the de novo, NAD(+) salvage,... biosynthesis, including the de novo, NAD(+) salvage, and nicotinamide riboside s

  19. Metal enhanced fluorescence of flavin mononucleotide using new plasmonic platform

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    Synak, Anna; Grobelna, Beata; Raut, Sangram; Bojarski, Piotr; Gryczyński, Ignacy; Karczewski, Jakub; Shtoyko, Tanya

    2016-09-01

    New plasmonic platform was successfully obtained to investigate the increase of fluorescence intensity of a fluorophore in the presence of silver nanoparticles. A flavin mononucleotide, was selected by us as a fluorophore for this study as a very important biological compound playing a key role in many biochemical process. Plasmonic platforms were characterized by means of luminescence spectroscopy. Flavin mononucleotide deposited on plasmonic platform exhibits dramatic emission enhancements in presence of silver nanoparticles deposited on gold mirror.

  20. Yeast Interacting Proteins Database: YLR328W, YLR328W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available YLR328W NMA1 Nicotinic acid mononucleotide adenylyltransferase, involved in pathways... of NAD biosynthesis, including the de novo, NAD(+) salvage, and nicotinamide riboside salvage pathways Row...ylyltransferase, involved in pathways of NAD biosynthesis, including the de novo,... NAD(+) salvage, and nicotinamide riboside salvage pathways Rows with this prey as prey (4) Rows with this p... description Nicotinic acid mononucleotide adenylyltransferase, involved in pathways

  1. Quasimonomorphic Mononucleotide Repeats for High-Level Microsatellite Instability Analysis

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    Olivier Buhard

    2004-01-01

    Full Text Available Microsatellite instability (MSI analysis is becoming more and more important to detect sporadic primary tumors of the MSI phenotype as well as in helping to determine Hereditary Non-Polyposis Colorectal Cancer (HNPCC cases. After some years of conflicting data due to the absence of consensus markers for the MSI phenotype, a meeting held in Bethesda to clarify the situation proposed a set of 5 microsatellites (2 mononucleotide repeats and 3 dinucleotide repeats to determine MSI tumors. A second Bethesda consensus meeting was held at the end of 2002. It was discussed here that the 1998 microsatellite panel could underestimate high-level MSI tumors and overestimate low-level MSI tumors. Amongst the suggested changes was the exclusive use of mononucleotide repeats in place of dinucleotide repeats. We have already proposed a pentaplex MSI screening test comprising 5 quasimonomorphic mononucleotide repeats. This article compares the advantages of mono or dinucleotide repeats in determining microsatellite instability.

  2. Adsorption mechanisms of RNA mononucleotides on silver nanoparticles.

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    Miljanić, Snežana; Dijanošić, Adriana; Matić, Ivona

    2015-02-25

    Surface-enhanced Raman scattering (SERS) of four RNA mononucleotides (AMP, GMP, CMP and UMP) has been studied on the citrate-reduced silver colloid aggregated with sodium sulfate. Concentration dependent spectra in the range of 1×10(-7)-1×10(-4) mol dm(-3) were obtained, assigned and interpreted according to the surface selection rules. For purine mononucleotides, AMP and GMP, adsorption onto the silver nanoparticles through the six-membered ring of the nitrogenous base was suggested. Concentration dependent splitting of the ring breathing band in the spectra of AMP indicated coexistence of two species on the silver surface, which differed in contribution of the adenine N1 atom and the exocyclic NH2 group in binding. Unlike the AMP spectra, the spectra of GMP implied only one mode of adsorption of the molecules onto the silver nanoparticles, taking place through the guanine N1H and C=O group. Weak SERS spectra of pyrimidine mononucleotides, CMP and UMP, pointed to involvement of carbonyl oxygen in adsorption process, whereby the molecules adopted the position on the nanoparticles with ribose close to the metal surface. Intense bands in the low wavenumber region, associated with stretching of the formed Ag-N and/or Ag-O bonds, supported chemical binding of the RNA mononucleotides with the silver surface. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Adsorption mechanisms of RNA mononucleotides on silver nanoparticles

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    Miljanić, Snežana; Dijanošić, Adriana; Matić, Ivona

    2015-02-01

    Surface-enhanced Raman scattering (SERS) of four RNA mononucleotides (AMP, GMP, CMP and UMP) has been studied on the citrate-reduced silver colloid aggregated with sodium sulfate. Concentration dependent spectra in the range of 1 × 10-7-1 × 10-4 mol dm-3 were obtained, assigned and interpreted according to the surface selection rules. For purine mononucleotides, AMP and GMP, adsorption onto the silver nanoparticles through the six-membered ring of the nitrogenous base was suggested. Concentration dependent splitting of the ring breathing band in the spectra of AMP indicated coexistence of two species on the silver surface, which differed in contribution of the adenine N1 atom and the exocyclic NH2 group in binding. Unlike the AMP spectra, the spectra of GMP implied only one mode of adsorption of the molecules onto the silver nanoparticles, taking place through the guanine N1H and Cdbnd O group. Weak SERS spectra of pyrimidine mononucleotides, CMP and UMP, pointed to involvement of carbonyl oxygen in adsorption process, whereby the molecules adopted the position on the nanoparticles with ribose close to the metal surface. Intense bands in the low wavenumber region, associated with stretching of the formed Agsbnd N and/or Agsbnd O bonds, supported chemical binding of the RNA mononucleotides with the silver surface.

  4. Reduced activity of glutamine synthetase in Rhodospirillum rubrum mutants lacking the adenylyltransferase GlnE.

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    Jonsson, Anders; Nordlund, Stefan; Teixeira, Pedro Filipe

    2009-10-01

    In the nitrogen-fixing bacterium Rhodospirillum rubrum, the GlnE adenylyltransferase (encoded by glnE) catalyzes reversible adenylylation of glutamine synthetase, thereby regulating nitrogen assimilation. We have generated glnE mutant strains that are unable to adenylylate glutamine synthetase (GS). Surprisingly, the activity of GS was lower in the mutants than in the wild type, even when grown in nitrogen-fixing conditions. Our results support the proposal that R. rubrum can only cope with the absence of an adenylylation system in the presence of lowered GS expression or activity. In general terms, this report also provides further support for the central role of GS in bacterial metabolism.

  5. Overexpression, crystallization and preliminary X-ray crystallographic analysis of phosphopantetheine adenylyltransferase from Enterococcus faecalis

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    Kang, Ji Yong; Lee, Hyung Ho; Yoon, Hye Jin; Kim, Hyoun Sook; Suh, Se Won, E-mail: sewonsuh@snu.ac.kr [Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2006-11-01

    Phosphopantetheine adenylyltransferase from En. faecalis was crystallized and X-ray diffraction data were collected to 2.70 Å resolution. Phosphopantetheine adenylyltransferase, an essential enzyme in the coenzyme A biosynthetic pathway, catalyzes the reversible transfer of an adenylyl group from ATP to 4′-phosphopantetheine, yielding 3′-dephospho-CoA and pyrophosphate. Enterococcus faecalis PPAT has been overexpressed in Escherichia coli as a fusion with a C-terminal purification tag and crystallized at 297 K using a reservoir solution consisting of 0.1 M sodium HEPES pH 7.5, 0.8 M sodium dihydrogen phosphate and 0.8 M potassium dihydrogen phosphate. X-ray diffraction data were collected to 2.70 Å at 100 K. The crystals belong to the primitive tetragonal space group P4{sub 1} (or P4{sub 3}), with unit-cell parameters a = b = 160.81, c = 225.68 Å. Four copies of the hexameric molecule are likely to be present in the asymmetric unit, giving a crystal volume per protein weight (V{sub M}) of 3.08 Å{sup 3} Da{sup −1} and a solvent content of 60.1%.

  6. Mononucleotide repeats are asymmetrically distributed in fungal genes

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    de Graaff Leo H

    2008-12-01

    Full Text Available Abstract Background Systematic analyses of sequence features have resulted in a better characterisation of the organisation of the genome. A previous study in prokaryotes on the distribution of sequence repeats, which are notoriously variable and can disrupt the reading frame in genes, showed that these motifs are skewed towards gene termini, specifically the 5' end of genes. For eukaryotes no such intragenic analysis has been performed, though this could indicate the pervasiveness of this distribution bias, thereby helping to expose the selective pressures causing it. Results In fungal gene repertoires we find a similar 5' bias of intragenic mononucleotide repeats, most notably for Candida spp., whereas e.g. Coccidioides spp. display no such bias. With increasing repeat length, ever larger discrepancies are observed in genome repertoire fractions containing such repeats, with up to an 80-fold difference in gene fractions at repeat lengths of 10 bp and longer. This species-specific difference in gene fractions containing large repeats could be attributed to variations in intragenic repeat tolerance. Furthermore, long transcripts experience an even more prominent bias towards the gene termini, with possibly a more adaptive role for repeat-containing short transcripts. Conclusion Mononucleotide repeats are intragenically biased in numerous fungal genomes, similar to earlier studies on prokaryotes, indicative of a similar selective pressure in gene organization.

  7. PeakSeeker: a program for interpreting genotypes of mononucleotide repeats

    Directory of Open Access Journals (Sweden)

    Salipante Stephen J

    2009-02-01

    Full Text Available Abstract Background Mononucleotide repeat microsatellites are abundant, highly polymorphic DNA sequences, having the potential to serve as valuable genetic markers. Use of mononucleotide microsatellites has been limited by their tendency to produce "stutter", confounding signals from insertions and deletions within the mononucleotide tract that occur during PCR, which complicates interpretation of genotypes by masking the true position of alleles. Consequently, microsatellites with larger repeating subunits (dinucleotide and trinucleotide motifs are used, which produce less stutter but are less genetically heterogeneous and less informative. A method to interpret the genotypes of mononucleotide repeats would permit the widespread use of those highly informative microsatellites in genetic research. Findings We have developed an approach to interpret genotypes of mononucleotide repeats using a software program, named PeakSeeker. PeakSeeker interprets experimental electropherograms as the most likely product of signals from individual alleles. Because mononucleotide tracts demonstrate locus-specific patterns of stutter peaks, this approach requires that the genotype pattern from a single allele is defined for each marker, which can be approximated by genotyping single DNA molecules or homozygotes. We have evaluated the program's ability to discriminate various types of homozygous and heterozygous mononucleotide loci using simulated and experimental data. Conclusion Mononucleotide tracts offer significant advantages over di- and tri-nucleotide microsatellite markers traditionally employed in genetic research. The PeakSeeker algorithm provides a high-throughput means to type mononucleotide tracts using conventional and widely implemented fragment length polymorphism genotyping. Furthermore, the PeakSeeker algorithm could potentially be adapted to improve, and perhaps to standardize, the analysis of conventional microsatellite genotypes.

  8. The effects of addition of mononucleotides on Sma nuc endonuclease activity.

    Science.gov (United States)

    Romanova, Julia; Filimonova, Maria

    2012-01-01

    Examination of the effects of mononucleotides on Sma nuc endonuclease originated from Gram negative bacterium Serratia marcescens displayed that any mononucleotide produced by Sma nuc during hydrolysis of DNA or RNA may regulate the enzyme activity affecting the RNase activity without pronounced influence on the activity towards DNA. The type of carbohydrate residue in mononucleotides does not affect the regulation. In contrast, the effects depend on the type of bases in nucleotides. AMP or dAMP was classified as a competitive inhibitor of partial type. GMP, UMP, and CMP were found to be uncompetitive inhibitors that suggest a specific site(s) for the nucleotide(s) binding in Sma nuc endonuclease.

  9. Crystallization and preliminary X-ray diffraction study of phosphopantetheine adenylyltransferase from M. tuberculosis crystallizing in space group P32

    Science.gov (United States)

    Timofeev, V. I.; Chupova, L. A.; Esipov, R. S.; Kuranova, I. P.

    2015-09-01

    Crystals of M. tuberculosis phosphopantetheine adenylyltransferase were grown in microgravity by the capillary counter-diffusion method through a gel layer. The X-ray diffraction data set suitable for the determination of the three-dimensional structure at atomic resolution was collected from one crystal at the Spring-8 synchrotron facility to 2.00-Å resolution. The crystals belong to sp. gr. P32 and have the following unit-cell parameters: a = b = 106.47 Å, c = 71.32 Å, α = γ = 90°, β = 120°. The structure was solved by the molecular-replacement method. There are six subunits of the enzyme comprising a hexamer per asymmetric unit. The hexamer is a biologically active form of phosphopantetheine adenylyltransferase from M. tuberculosis.

  10. Controlling the reactivity of chlorinated ethylenes with flavin mononucleotide hydroquinone.

    Science.gov (United States)

    Ciptadjaya, Christopher G E; Guo, Wen; Angeli, Jayni M; Obare, Sherine O

    2009-03-01

    Reduction rate constants of the chlorinated ethylenes cis-1,2-dichloroethylene (cis-DCE), trichloroethylene (TCE), and tetrachloroethylene (PCE) reacted with flavin mononucleotide hydroquinone (FMNH2) under anoxic conditions were investigated. FMNH2 was produced in methanol solvent by the photoreduction of FMN. In aqueous solution, FMN was not fully reduced to FMNH2 but instead yielded the semiquinone radical FMNH*. However, when FMN was anchored to nanocrystalline TiO2, band gap irradiation resulted in electron transfer from the TiO2 conduction band to FMN, thus yielding FMNH2. The FMNH2 generated in aqueous solution on the TiO2 surface was a stronger reductant toward chlorinated ethylenes, relative to FMNH2 in solution. Furthermore, by combining the reactivity of the TiO2 conduction band electrons [TiO2(e-(CB)] with FMNH2, reduction rate constants for the chlorinated ethylenes increased by 2 orders of magnitude relative to FMNH2 alone. The results show how biological molecules such as FMNH2 could have significant effects toward the remediation of organic pollutants.

  11. Coenzyme Recognition and Gene Regulation by a Flavin Mononucleotide Riboswitch

    Energy Technology Data Exchange (ETDEWEB)

    Serganov, A.; Huang, L; Patel, D

    2009-01-01

    The biosynthesis of several protein cofactors is subject to feedback regulation by riboswitches. Flavin mononucleotide (FMN)-specific riboswitches also known as RFN elements, direct expression of bacterial genes involved in the biosynthesis and transport of riboflavin (vitamin B2) and related compounds. Here we present the crystal structures of the Fusobacterium nucleatum riboswitch bound to FMN, riboflavin and antibiotic roseoflavin. The FMN riboswitch structure, centred on an FMN-bound six-stem junction, does not fold by collinear stacking of adjacent helices, typical for folding of large RNAs. Rather, it adopts a butterfly-like scaffold, stapled together by opposingly directed but nearly identically folded peripheral domains. FMN is positioned asymmetrically within the junctional site and is specifically bound to RNA through interactions with the isoalloxazine ring chromophore and direct and Mg{sup 2+}-mediated contacts with the phosphate moiety. Our structural data, complemented by binding and footprinting experiments, imply a largely pre-folded tertiary RNA architecture and FMN recognition mediated by conformational transitions within the junctional binding pocket. The inherent plasticity of the FMN-binding pocket and the availability of large openings make the riboswitch an attractive target for structure-based design of FMN-like antimicrobial compounds. Our studies also explain the effects of spontaneous and antibiotic-induced deregulatory mutations and provided molecular insights into FMN-based control of gene expression in normal and riboflavin-overproducing bacterial strains.

  12. Nicotinamide mononucleotide inhibits JNK activation to reverse Alzheimer disease.

    Science.gov (United States)

    Yao, Zhiwen; Yang, Wenhao; Gao, Zhiqiang; Jia, Peng

    2017-04-24

    Amyloid-β (Aβ) oligomers have been accepted as major neurotoxic agents in the therapy of Alzheimer's disease (AD). It has been shown that the activity of nicotinamide adenine dinucleotide (NAD+) is related with the decline of Aβ toxicity in AD. Nicotinamide mononucleotide (NMN), the important precursor of NAD+, is produced during the reaction of nicotinamide phosphoribosyl transferase (Nampt). This study aimed to figure out the potential therapeutic effects of NMN and its underlying mechanisms in APPswe/PS1dE9 (AD-Tg) mice. We found that NMN gave rise to a substantial improvement in behavioral measures of cognitive impairments compared to control AD-Tg mice. In addition, NMN treatment significantly decreased β-amyloid production, amyloid plaque burden, synaptic loss, and inflammatory responses in transgenic animals. Mechanistically, NMN effectively controlled JNK activation. Furthermore, NMN potently progressed nonamyloidogenic amyloid precursor protein (APP) and suppressed amyloidogenic APP by mediating the expression of APP cleavage secretase in AD-Tg mice. Based on our findings, it was suggested that NMN substantially decreases multiple AD-associated pathological characteristically at least partially by the inhibition of JNK activation. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Mobility of a Mononucleotide within a Lipid Matrix: A Neutron Scattering Study

    Science.gov (United States)

    Misuraca, Loreto; Natali, Francesca; da Silva, Laura; Peters, Judith; Demé, Bruno; Ollivier, Jacques; Seydel, Tilo; Laux-Lesourd, Valerie; Haertlein, Michael; Zaccai, Giuseppe; Deamer, David; Maurel, Marie Christine

    2017-01-01

    An essential question in studies on the origins of life is how nucleic acids were first synthesized and then incorporated into compartments about 4 billion years ago. A recent discovery is that guided polymerization within organizing matrices could promote a non-enzymatic condensation reaction allowing the formation of RNA-like polymers, followed by encapsulation in lipid membranes. Here, we used neutron scattering and deuterium labelling to investigate 5′-adenosine monophosphate (AMP) molecules captured in a multilamellar phospholipid matrix. The aim of the research was to determine and compare how mononucleotides are captured and differently organized within matrices and multilamellar phospholipid structures and to explore the role of water in organizing the system to determine at which level the system becomes sufficiently anhydrous to lock the AMP molecules into an organized structure and initiate ester bond synthesis. Elastic incoherent neutron scattering experiments were thus employed to investigate the changes of the dynamic properties of AMP induced by embedding the molecules within the lipid matrix. The influence of AMP addition to the lipid membrane organization was determined through diffraction measurement, which also helped us to define the best working Q range for dynamical data analysis with respect to specific hydration. The use of different complementary instruments allowed coverage of a wide time-scale domain, from ns to ps, of atomic mean square fluctuations, providing evidence of a well-defined dependence of the AMP dynamics on the hydration level. PMID:28054992

  14. NRK1 controls nicotinamide mononucleotide and nicotinamide riboside metabolism in mammalian cells.

    Science.gov (United States)

    Ratajczak, Joanna; Joffraud, Magali; Trammell, Samuel A J; Ras, Rosa; Canela, Núria; Boutant, Marie; Kulkarni, Sameer S; Rodrigues, Marcelo; Redpath, Philip; Migaud, Marie E; Auwerx, Johan; Yanes, Oscar; Brenner, Charles; Cantó, Carles

    2016-10-11

    NAD(+) is a vital redox cofactor and a substrate required for activity of various enzyme families, including sirtuins and poly(ADP-ribose) polymerases. Supplementation with NAD(+) precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), protects against metabolic disease, neurodegenerative disorders and age-related physiological decline in mammals. Here we show that nicotinamide riboside kinase 1 (NRK1) is necessary and rate-limiting for the use of exogenous NR and NMN for NAD(+) synthesis. Using genetic gain- and loss-of-function models, we further demonstrate that the role of NRK1 in driving NAD(+) synthesis from other NAD(+) precursors, such as nicotinamide or nicotinic acid, is dispensable. Using stable isotope-labelled compounds, we confirm NMN is metabolized extracellularly to NR that is then taken up by the cell and converted into NAD(+). Our results indicate that mammalian cells require conversion of extracellular NMN to NR for cellular uptake and NAD(+) synthesis, explaining the overlapping metabolic effects observed with the two compounds.

  15. Characterization of recombinant human nicotinamide mononucleotide adenylyl transferase (NMNAT), a nuclear enzyme essential for NAD synthesis.

    Science.gov (United States)

    Schweiger, M; Hennig, K; Lerner, F; Niere, M; Hirsch-Kauffmann, M; Specht, T; Weise, C; Oei, S L; Ziegler, M

    2001-03-09

    Nicotinamide mononucleotide adenylyl transferase (NMNAT) is an essential enzyme in all organisms, because it catalyzes a key step of NAD synthesis. However, little is known about the structure and regulation of this enzyme. In this study we established the primary structure of human NMNAT. The human sequence represents the first report of the primary structure of this enzyme for an organism higher than yeast. The enzyme was purified from human placenta and internal peptide sequences determined. Analysis of human DNA sequence data then permitted the cloning of a cDNA encoding this enzyme. Recombinant NMNAT exhibited catalytic properties similar to the originally purified enzyme. Human NMNAT (molecular weight 31932) consists of 279 amino acids and exhibits substantial structural differences to the enzymes from lower organisms. A putative nuclear localization signal was confirmed by immunofluorescence studies. NMNAT strongly inhibited recombinant human poly(ADP-ribose) polymerase 1, however, NMNAT was not modified by poly(ADP-ribose). NMNAT appears to be a substrate of nuclear kinases and contains at least three potential phosphorylation sites. Endogenous and recombinant NMNAT were phosphorylated in nuclear extracts in the presence of [gamma-(32)P]ATP. We propose that NMNAT's activity or interaction with nuclear proteins are likely to be modulated by phosphorylation.

  16. The Effects of Addition of Mononucleotides on Sma nuc Endonuclease Activity

    Directory of Open Access Journals (Sweden)

    Julia Romanova

    2012-01-01

    Full Text Available Examination of the effects of mononucleotides on Sma nuc endonuclease originated from Gram negative bacterium Serratia marcescens displayed that any mononucleotide produced by Sma nuc during hydrolysis of DNA or RNA may regulate the enzyme activity affecting the RNase activity without pronounced influence on the activity towards DNA. The type of carbohydrate residue in mononucleotides does not affect the regulation. In contrast, the effects depend on the type of bases in nucleotides. AMP or dAMP was classified as a competitive inhibitor of partial type. GMP, UMP, and CMP were found to be uncompetitive inhibitors that suggest a specific site(s for the nucleotide(s binding in Sma nuc endonuclease.

  17. Cyclic mononucleotides modulate potassium and calcium flux responses to H2O2 in Arabidopsis roots

    KAUST Repository

    Ordoñez, Natalia Maria

    2014-02-13

    Cyclic mononucleotides are messengers in plant stress responses. Here we show that hydrogen peroxide (H2O2) induces rapid net K+-efflux and Ca2+-influx in Arabidopsis roots. Pre-treatment with either 10 μM cAMP or cGMP for 1 or 24 h does significantly reduce net K+-leakage and Ca2+-influx, and in the case of the K+-fluxes, the cell permeant cyclic mononucleotides are more effective. We also examined the effect of 10 μM of the cell permeant 8-Br-cGMP on the Arabidopsis microsomal proteome and noted a specific increase in proteins with a role in stress responses and ion transport, suggesting that cGMP is sufficient to directly and/or indirectly induce complex adaptive changes to cellular stresses induced by H2O2. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  18. NRK1 controls nicotinamide mononucleotide and nicotinamide riboside metabolism in mammalian cells

    OpenAIRE

    Ratajczak, Joanna; Joffraud, Magali; Trammell, Samuel A.J.; Ras, Rosa; Canela, Nuria; Boutant, Marie; Kulkarni, Sameer S; Rodrigues,Marcelo; Redpath, Philip; Migaud, Marie E.; Auwerx, Johan; Yanes, Oscar; Brenner, Charles; Cantó, Carles

    2016-01-01

    NAD+ is a vital redox cofactor and a substrate required for activity of various enzyme families, including sirtuins and poly(ADP-ribose) polymerases. Supplementation with NAD+ precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), protects against metabolic disease, neurodegenerative disorders and age-related physiological decline in mammals. Here we show that nicotinamide riboside kinase 1 (NRK1) is necessary and rate-limiting for the use of exogenous NR and NMN...

  19. Crystallization and preliminary X-ray diffraction study of phosphopantetheine adenylyltransferase from M. tuberculosis crystallizing in space group P3{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, V. I., E-mail: tostars@mail.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Chupova, L. A.; Esipov, R. S. [Russian Academy of Sciences, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Kuranova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2015-09-15

    Crystals of M. tuberculosis phosphopantetheine adenylyltransferase were grown in microgravity by the capillary counter-diffusion method through a gel layer. The X-ray diffraction data set suitable for the determination of the three-dimensional structure at atomic resolution was collected from one crystal at the Spring-8 synchrotron facility to 2.00-Å resolution. The crystals belong to sp. gr. P3{sub 2} and have the following unit-cell parameters: a = b = 106.47 Å, c = 71.32 Å, α = γ = 90°, β = 120°. The structure was solved by the molecular-replacement method. There are six subunits of the enzyme comprising a hexamer per asymmetric unit. The hexamer is a biologically active form of phosphopantetheine adenylyltransferase from M. tuberculosis.

  20. Template-directed ligation of tethered mononucleotides by t4 DNA ligase for kinase ribozyme selection.

    Directory of Open Access Journals (Sweden)

    David G Nickens

    Full Text Available BACKGROUND: In vitro selection of kinase ribozymes for small molecule metabolites, such as free nucleosides, will require partition systems that discriminate active from inactive RNA species. While nucleic acid catalysis of phosphoryl transfer is well established for phosphorylation of 5' or 2' OH of oligonucleotide substrates, phosphorylation of diffusible small molecules has not been demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: This study demonstrates the ability of T4 DNA ligase to capture RNA strands in which a tethered monodeoxynucleoside has acquired a 5' phosphate. The ligation reaction therefore mimics the partition step of a selection for nucleoside kinase (deoxyribozymes. Ligation with tethered substrates was considerably slower than with nicked, fully duplex DNA, even though the deoxynucleotides at the ligation junction were Watson-Crick base paired in the tethered substrate. Ligation increased markedly when the bridging template strand contained unpaired spacer nucleotides across from the flexible tether, according to the trends: A(2>A(1>A(3>A(4>A(0>A(6>A(8>A(10 and T(2>T(3>T(4>T(6 approximately T(1>T(8>T(10. Bridging T's generally gave higher yield of ligated product than bridging A's. ATP concentrations above 33 microM accumulated adenylated intermediate and decreased yields of the gap-sealed product, likely due to re-adenylation of dissociated enzyme. Under optimized conditions, T4 DNA ligase efficiently (>90% joined a correctly paired, or TratioG wobble-paired, substrate on the 3' side of the ligation junction while discriminating approximately 100-fold against most mispaired substrates. Tethered dC and dG gave the highest ligation rates and yields, followed by tethered deoxyinosine (dI and dT, with the slowest reactions for tethered dA. The same kinetic trends were observed in ligase-mediated capture in complex reaction mixtures with multiple substrates. The "universal" analog 5-nitroindole (dNI did not support ligation when

  1. Modifying the collagen framework of costal cartilage under the impact of UV and a flavin mononucleotide

    Science.gov (United States)

    Ignat'eva, N. Yu.; Zakharkina, O. L.; Semchishen, V. A.; Molchanov, M. D.; Lunin, V. V.; Bagratashvili, V. N.

    2016-03-01

    Modifications of the matrix of the tissue of costal cartilage under the impact of UV (λ = 365 nm) and a flavin mononucleotide (FMN) is studied. The changes in the macroscopic properties of the tissue are detected by means of differential scanning calorimetry and under the conditions of uniaxial compression during mechanical testing. The endothermic effects of the denaturation of the collagen framework of the tissue and the Young's modulus are determined. It is shown that the presence of a flavin mononucleotide in the interstitial fluid leads lowers the temperature of collagen denaturation by 2.5°C and doubles the Young's modulus. It is found that the temperature of denaturation and the Young's modulus grow gradually after treating the tissue with the UV radiation, and their values ultimately exceed by far the corresponding values for intact samples. It is concluded that the obtained data indicate the possibility of stabilizing the framework of the matrix of costal cartilage under the impact of UV radiation and a flavin mononucleotide.

  2. Binding constants of phenylalanine for the four mononucleotides

    Science.gov (United States)

    Khaled, M. A.; Mullins, D. W., Jr.; Lacey, J. C., Jr.

    1984-01-01

    Earlier work has shown that several properties of amino acids correlate directly with properties of their anticodonic nucleotides. Furthermore, in precipitation studies with thermal proteinoids and homopolyribonucleotides, an anticodonic preference was displayed between Lys-rich, Pro-rich and Gly-rich thermal proteinoids and their anticodonic polyribonucleotides. However, Phe-rich thermal proteinoid displayed a preference for its codonic nucleotide, poly U. This inconsistency seemed to be explained by a folding in of the hydrophobic residues of Phe causing the proteinoid to appear more hydrophilic. The present work used nuclear magnetic resonance techniques to resolve a limited question: to which of the four nucleotides does Phe bind most strongly? The results show quite clearly that Phe binds most strongly to its anticodonic nucleotide, AMP.

  3. Reaction mechanism of adenylyltransferase DrrA from Legionella pneumophila elucidated by time-resolved fourier transform infrared spectroscopy.

    Science.gov (United States)

    Gavriljuk, Konstantin; Schartner, Jonas; Itzen, Aymelt; Goody, Roger S; Gerwert, Klaus; Kötting, Carsten

    2014-07-01

    Modulation of the function of small GTPases that regulate vesicular trafficking is a strategy employed by several human pathogens. Legionella pneumophila infects lung macrophages and injects a plethora of different proteins into its host cell. Among these is DrrA/SidM, which catalyzes stable adenylylation of Rab1b, a regulator of endoplasmatic reticulum to Golgi trafficking, and thereby alters the function and interactions of this small GTPase. We employed time-resolved FTIR-spectroscopy to monitor the DrrA-catalyzed AMP-transfer to Tyr77 of Rab1b. A transient complex between DrrA, adenylylated Rab1b, and the pyrophosphate byproduct was resolved, allowing us to analyze the interactions at the active site. Combination of isotopic labeling and site-directed mutagenesis allowed us to derive the catalytic mechanism of DrrA from the FTIR difference spectra. DrrA shares crucial residues in the ATP-binding pocket with similar AMP-transferring enzymes such as glutamine synthetase adenylyltransferase or kanamycin nucleotidyltransferase, but provides the complete active site on a single subunit. We determined that Asp112 of DrrA functions as the catalytic base for deprotonation of Tyr77 of Rab1b to enable nucleophilic attack on the ATP. The study provides detailed understanding of the Legionella pneumophila protein DrrA and of AMP-transfer reactions in general.

  4. Dissolution and mixing of flavin mononucleotide in microfluidic chips for bioassay

    Science.gov (United States)

    Belousov, K. I.; Denisov, I. A.; Lukyanenko, K. A.; Yakimov, A. S.; Bukatin, A. S.; Kukhtevich, I. V.; Sorokin, V. V.; Esimbekova, E. N.; Belobrov, P. I.; Evstrapov, A. A.

    2016-08-01

    Dissolution and mixing of flavin mononucleotide (FMN), which activates a luminescent reaction, were considered in various designs of microfluidic chip for pollution analysis of liquid samples. The aim was to determine the velocity mode of fluid flow ensured the uniform distribution of the FMN in the reaction chamber. Simulation of concentration distribution of FMN in various designs of microfluidic chips was conducted. It was shown that the passive mixing techniques based on the constant flow rate didn't provide mixing of FMN in acceptable time (3 seconds). The most efficient mixing was achieved using variable flow rate with a gradually increasing frequency of oscillation.

  5. Truncated FAD synthetase for direct biocatalytic conversion of riboflavin and analogs to their corresponding flavin mononucleotides.

    Science.gov (United States)

    Iamurri, Samantha M; Daugherty, Ashley B; Edmondson, Dale E; Lutz, Stefan

    2013-12-01

    The preparation of flavin mononucleotide (FMN) and FMN analogs from their corresponding riboflavin precursors is traditionally performed in a two-step procedure. After initial enzymatic conversion of riboflavin to flavin adenine dinucleotide (FAD) by a bifunctional FAD synthetase, the adenyl moiety of FAD is hydrolyzed with snake venom phosphodiesterase to yield FMN. To simplify the protocol, we have engineered the FAD synthetase from Corynebacterium ammoniagenes by deleting its N-terminal adenylation domain. The newly created biocatalyst is stable and efficient for direct and quantitative phosphorylation of riboflavin and riboflavin analogs to their corresponding FMN cofactors at preparative-scale.

  6. Simultaneous quantitation of nicotinamide riboside, nicotinamide mononucleotide and nicotinamide adenine dinucleotide in milk by a novel enzyme-coupled assay.

    Science.gov (United States)

    Ummarino, Simone; Mozzon, Massimo; Zamporlini, Federica; Amici, Adolfo; Mazzola, Francesca; Orsomando, Giuseppe; Ruggieri, Silverio; Raffaelli, Nadia

    2017-04-15

    Nicotinamide riboside, the most recently discovered form of vitamin B3, and its phosphorylated form nicotinamide mononucleotide, have been shown to be potent supplements boosting intracellular nicotinamide adenine dinucleotide (NAD) levels, thus preventing or ameliorating metabolic and mitochondrial diseases in mouse models. Here we report for the first time on the simultaneous quantitation of nicotinamide riboside, nicotinamide mononucleotide and NAD in milk by means of a fluorometric, enzyme-coupled assay. Application of this assay to milk from different species revealed that the three vitamers were present in human and donkey milk, while being selectively distributed in the other milks. Human milk was the richest source of nicotinamide mononucleotide. Overall, the three vitamers accounted for a significant fraction of total vitamin B3 content. Pasteurization did not affect the bovine milk content of nicotinamide riboside, whereas UHT processing fully destroyed the vitamin. In human milk, NAD levels were significantly affected by the lactation time.

  7. Bioluminophore and Flavin Mononucleotide Fluorescence Quenching of Bacterial Bioluminescence-A Theoretical Study.

    Science.gov (United States)

    Luo, Yanling; Liu, Ya-Jun

    2016-11-02

    Bacterial bioluminescence with continuous glow has been applied to the fields of environmental toxin monitoring, drug screening, and in vivo imaging. Nonetheless, the chemical form of the bacterial bioluminophore is still a bone of contention. Flavin mononucleotide (FMN), one of the light-emitting products, and 4a-hydroxy-5-hydro flavin mononucleotide (HFOH), an intermediate of the chemical reactions, have both been assumed candidates for the light emitter because they have similar molecular structures and fluorescence wavelengths. The latter is preferred in experiments and was assigned in our previous density functional study. HFOH displays weak fluorescence in solutions, but exhibits strong bioluminescence in the bacterial luciferase. FMN shows the opposite behavior; its fluorescence is quenched when it is bound to the luciferase. This is the first example of flavin fluorescence quenching observed in bioluminescent systems and is merely an observation, both the quenching mechanism and quencher are still unclear. Based on theoretical analysis of high-level quantum mechanics (QM), combined QM and molecular mechanics (QM/MM), and molecular dynamics (MD), this paper confirms that HFOH in its first singlet excited state is the bioluminophore of bacterial bioluminescence. More importantly, the computational results indicate that Tyr110 in the luciferase quenches the FMN fluorescence via an electron-transfer mechanism.

  8. N3 and O2 Protonated Conformers of the Cytosine Mononucleotides Coexist in the Gas Phase

    Science.gov (United States)

    Wu, R. R.; Hamlow, L. A.; He, C. C.; Nei, Y.-w.; Berden, G.; Oomens, J.; Rodgers, M. T.

    2017-08-01

    The gas-phase conformations of the protonated forms of the DNA and RNA cytosine mononucleotides, [pdCyd+H]+ and [pCyd+H]+, are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy over the IR fingerprint and hydrogen-stretching regions complemented by electronic structure calculations. The low-energy conformations of [pdCyd+H]+ and [pCyd+H]+ and their relative stabilities are computed at the B3LYP/6-311+G(2d,2p)//B3LYP/6-311+G(d,p) and MP2(full)/6-311+G(2d,2p)//B3LYP/6-311+G(d,p) levels of theory. Comparisons of the measured IRMPD action spectra and B3LYP/6-311+G(d,p) linear IR spectra computed for the low-energy conformers allow the conformers present in the experiments to be determined. Similar to that found in previous IRMPD action spectroscopy studies of the protonated forms of the cytosine nucleosides, [dCyd+H]+ and [Cyd+H]+, both N3 and O2 protonated cytosine mononucleotides exhibiting an anti orientation of cytosine are found to coexist in the experimental population. The 2'-hydroxyl substituent does not significantly influence the most stable conformations of [pCyd+H]+ versus those of [pdCyd+H]+, as the IRMPD spectral profiles of [pdCyd+H]+ and [pCyd+H]+ are similar. However, the presence of the 2'-hydroxyl substituent does influence the relative intensities of the measured IRMPD bands. Comparisons to IRMPD spectroscopy studies of the deprotonated forms of the cytosine mononucleotides, [pdCyd-H]- and [pCyd-H]-, provide insight into the effects of protonation versus deprotonation on the conformational features of the nucleobase and sugar moieties. Likewise, comparisons to results of IRMPD spectroscopy studies of the protonated cytosine nucleosides provide insight into the influence of the phosphate moiety on structure. Comparison with previous ion mobility results shows the superiority of IRMPD spectroscopy for distinguishing various protonation sites.

  9. Preparation of the Crystal Complex of Phosphopantetheine Adenylyltransferase from Mycobacterium tuberculosis with Coenzyme A and Investigation of Its Three-Dimensional Structure at 2.1-Å Resolution

    Science.gov (United States)

    Timofeev, V. I.; Smirnova, E. A.; Chupova, L. A.; Esipov, R. S.; Kuranova, I. P.

    2010-11-01

    Recombinant phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis (PPAT Mt), which was produced by a high-producing strain and purified to 99%, was used for the crystal growth of the complex of the enzyme with coenzyme A (CoA). Crystals suitable for X-ray diffraction study were obtained by cocrystallization. The crystals belong to sp. gr. R32 and have the unit-cell parameters a = b = 98.840 Å, c = 112.880 Å, α = β = 90.00°, and γ = 120.00°. The three-dimensional structure of the complex was determined based on X-ray diffraction data collected from the crystals to 2.1 Å resolution and refined to Rf = 22.7% and Rfree = 25.93%. Active-site bound coenzyme A was found, and its nearest environment was described. The conformational changes of the enzyme due to ligand binding were revealed. The binding of CoA by tuberculosis phosphopantetheine adenylyltransferase was characterized by comparing the structures of the title complex to a similar complex of PPAT from E. coli (PPAT Ec).

  10. Preparation of the Crystal Complex of Phosphopantetheine Adenylyltransferase from Mycobacterium tuberculosis with Coenzyme A and Investigation of Its Three-Dimensional Structure at 2.1-A Resolution

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, V. I.; Smirnova, E. A., E-mail: inna@ns.crys.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Chupova, L. A.; Esipov, R. S. [Russian Academy of Sciences, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Kuranova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2010-11-15

    Recombinant phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis (PPAT Mt), which was produced by a high-producing strain and purified to 99%, was used for the crystal growth of the complex of the enzyme with coenzyme A (CoA). Crystals suitable for X-ray diffraction study were obtained by cocrystallization. The crystals belong to sp. gr. R32 and have the unit-cell parameters a = b = 98.840 A, c = 112.880 A, {alpha} = {beta} = 90.00{sup o}, and {gamma} = 120.00{sup o}. The three-dimensional structure of the complex was determined based on X-ray diffraction data collected from the crystals to 2.1 A resolution and refined to Rf = 22.7% and Rfree = 25.93%. Active-site bound coenzyme A was found, and its nearest environment was described. The conformational changes of the enzyme due to ligand binding were revealed. The binding of CoA by tuberculosis phosphopantetheine adenylyltransferase was characterized by comparing the structures of the title complex to a similar complex of PPAT from E. coli (PPAT Ec).

  11. Structural and molecular basis for resistance to aminoglycoside antibiotics by the adenylyltransferase ANT(2″)-Ia.

    Science.gov (United States)

    Cox, Georgina; Stogios, Peter J; Savchenko, Alexei; Wright, Gerard D

    2015-01-01

    The aminoglycosides are highly effective broad-spectrum antimicrobial agents. However, their efficacy is diminished due to enzyme-mediated covalent modification, which reduces affinity of the drug for the target ribosome. One of the most prevalent aminoglycoside resistance enzymes in Gram-negative pathogens is the adenylyltransferase ANT(2″)-Ia, which confers resistance to gentamicin, tobramycin, and kanamycin. Despite the importance of this enzyme in drug resistance, its structure and molecular mechanism have been elusive. This study describes the structural and mechanistic basis for adenylylation of aminoglycosides by the ANT(2″)-Ia enzyme. ANT(2″)-Ia confers resistance by magnesium-dependent transfer of a nucleoside monophosphate (AMP) to the 2″-hydroxyl of aminoglycoside substrates containing a 2-deoxystreptamine core. The catalyzed reaction follows a direct AMP transfer mechanism from ATP to the substrate antibiotic. Central to catalysis is the coordination of two Mg(2+) ions, positioning of the modifiable substrate ring, and the presence of a catalytic base (Asp86). Comparative structural analysis revealed that ANT(2″)-Ia has a two-domain structure with an N-terminal active-site architecture that is conserved among other antibiotic nucleotidyltransferases, including Lnu(A), LinB, ANT(4')-Ia, ANT(4″)-Ib, and ANT(6)-Ia. There is also similarity between the nucleotidyltransferase fold of ANT(2″)-Ia and DNA polymerase β. This similarity is consistent with evolution from a common ancestor, with the nucleotidyltransferase fold having adapted for activity against chemically distinct molecules. IMPORTANCE  : To successfully manage the threat associated with multidrug-resistant infectious diseases, innovative therapeutic strategies need to be developed. One such approach involves the enhancement or potentiation of existing antibiotics against resistant strains of bacteria. The reduction in clinical usefulness of the aminoglycosides is a particular

  12. Target genes of microsatellite sequences in head and neck squamous cell carcinoma: mononucleotide repeats are not detected.

    Science.gov (United States)

    Wang, Yimin; Liu, Xuejuan; Li, Yulin

    2012-09-10

    Microsatellite instability (MSI) is detected in a wide variety of tumors. It is thought that mismatch repair gene mutation or inactivation is the major cause of MSI. Microsatellite sequences are predominantly distributed in intergenic or intronic DNA. However, MSI is found in the exonic sequences of some genes, causing their inactivation. In this report, we searched GenBank for candidate genes containing potential MSI sequences in exonic regions. Twenty seven target genes were selected for MSI analysis. Instability was found in 70% of these genes (14/20) with head and neck squamous cell carcinoma (HNSCC). Interestingly, no instability was detected in mononucleotide repeats in genes or in intergenic sequences. We conclude that instability of mononucleotide repeats is a rare event in HNSCC. High MSI phenotype in young HNSCC patients is limited to noncoding regions only. MSI percentage in HNSCC tumor is closely related to the repeat type, repeat location and patient's age.

  13. A highly specialized flavin mononucleotide riboswitch responds differently to similar ligands and confers roseoflavin resistance to Streptomyces davawensis.

    Science.gov (United States)

    Pedrolli, Danielle Biscaro; Matern, Andreas; Wang, Joy; Ester, Miriam; Siedler, Kathrin; Breaker, Ronald; Mack, Matthias

    2012-09-01

    Streptomyces davawensis is the only organism known to synthesize the antibiotic roseoflavin, a riboflavin (vitamin B2) analog. Roseoflavin is converted to roseoflavin mononucleotide (RoFMN) and roseoflavin adenine dinucleotide in the cytoplasm of target cells. (Ribo-)Flavin mononucleotide (FMN) riboswitches are genetic elements, which in many bacteria control genes responsible for the biosynthesis and transport of riboflavin. Streptomyces davawensis is roseoflavin resistant, and the closely related bacterium Streptomyces coelicolor is roseoflavin sensitive. The two bacteria served as models to investigate roseoflavin resistance of S. davawensis and to analyze the mode of action of roseoflavin in S. coelicolor. Our experiments demonstrate that the ribB FMN riboswitch of S. davawensis (in contrast to the corresponding riboswitch of S. coelicolor) is able to discriminate between the two very similar flavins FMN and RoFMN and shows opposite responses to the latter ligands.

  14. Structure of Mycobacterium tuberculosis phosphopantetheine adenylyltransferase in complex with the feedback inhibitor CoA reveals only one active-site conformation

    Energy Technology Data Exchange (ETDEWEB)

    Wubben, T.; Mesecar, A.D. (Purdue); (UIC)

    2014-10-02

    Phosphopantetheine adenylyltransferase (PPAT) catalyzes the penultimate step in the coenzyme A (CoA) biosynthetic pathway, reversibly transferring an adenylyl group from ATP to 4'-phosphopantetheine to form dephosphocoenzyme A (dPCoA). To complement recent biochemical and structural studies on Mycobacterium tuberculosis PPAT (MtPPAT) and to provide further insight into the feedback regulation of MtPPAT by CoA, the X-ray crystal structure of the MtPPAT enzyme in complex with CoA was determined to 2.11 {angstrom} resolution. Unlike previous X-ray crystal structures of PPAT-CoA complexes from other bacteria, which showed two distinct CoA conformations bound to the active site, only one conformation of CoA is observed in the MtPPAT-CoA complex.

  15. Crystal growth of phosphopantetheine adenylyltransferase, carboxypeptidase t, and thymidine phosphorylase on the international space station by the capillary counter-diffusion method

    Energy Technology Data Exchange (ETDEWEB)

    Kuranova, I. P., E-mail: inna@ns.crys.ras.ru; Smirnova, E. A.; Abramchik, Yu. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Chupova, L. A.; Esipov, R. S. [Russian Academy of Sciences, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Akparov, V. Kh. [Research Institute for Genetics and Selection of Industrial Microorganisms, Scientific Center of Russian Federation (Russian Federation); Timofeev, V. I.; Kovalchuk, M. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2011-09-15

    Crystals of phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis, thymidine phosphorylase from Escherichia coli, carboxypeptidase T from Thermoactinomyces vulgaris and its mutant forms, and crystals of complexes of these proteins with functional ligands and inhibitors were grown by the capillary counter-diffusion method in the Japanese Experimental Module Kibo on the International Space Station. The high-resolution X-ray diffraction data sets suitable for the determination of high-resolution three-dimensional structures of these proteins were collected from the grown crystals on the SPring-8 synchrotron radiation facility. The conditions of crystal growth for the proteins and the data-collection statistics are reported. The crystals grown in microgravity diffracted to a higher resolution than crystals of the same proteins grown on Earth.

  16. Two-electron reduction of nitroaromatic compounds by flavin mononucleotide. DFT computational study

    Directory of Open Access Journals (Sweden)

    Liudmyla K. Sviatenko

    2016-08-01

    Full Text Available The mechanism for reduction of nitroaromatic compounds by flavin mononucleotide (FMN was examined at MPWB1K/tzvp level. The solvent effects were calculated using a PCM(Pauling and SMD(Pauling solvation models for ions and neutral molecules, respectively. Calculated thermodynamics of the reduction of nitro group to nitroso group suggests consequtive four-steps’ process (electron–proton–electron–proton transfer where the first proton comes from solution, while the second one – from FMN. Water molecule releases during fourth step of the process. Electron attachment to nitrocompound and electron lose by reduced FMN facilitate the breaking of N–O bond and proton release, respectively. Calculations show that reduction of nitro group to nitroso group in studied nitrocompounds is a thermodynamically feasible with 56–59 kcal/mol Gibbs free energy release. The most easy electron transfer proceeds for TNT (2,4,6-trinitrotoluene and NTO (5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one. While the most energy release occurs during proton transfer in case of ANTA (5-amino-3-nitro-1H-1,2,4-triazole.

  17. Gas-phase hydrogen/deuterium exchange of 5'- and 3'-mononucleotides in a quadrupole ion trap: exploring the role of conformation and system energy.

    Science.gov (United States)

    Chipuk, Joseph E; Brodbelt, Jennifer S

    2007-04-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions for deprotonated 2'-deoxy-5'-monophosphate and 2'-deoxy-3'-monophosphate nucleotides with D(2)O were performed in a quadrupole ion trap mass spectrometer. To augment these experiments, molecular modeling was also conducted to identify likely deprotonation sites and potential gas-phase conformations of the anions. A majority of the 5'-monophosphates exchanged extensively with several of the compounds completely incorporating deuterium in place of their labile hydrogen atoms. In contrast, most of the 3'-monophosphate isomers exchanged relatively few hydrogen atoms, even though the rate of the first two exchanges was greater than observed for the 5'-monophosphates. Mononucleotides that failed to incorporate more than two deuterium atoms under default reaction conditions were often found to exchange more extensively when reactions were performed under higher energy conditions. Integration of the experimental and theoretical results supports the use of a relay exchange mechanism and suggests that the exchange behavior depends highly on the identity and orientation of the nucleobase and the position and flexibility of the deprotonated phosphate moiety. These observations also highlight the importance of the distance between the various participating groups in addition to their gas-phase acidity and basicity.

  18. Three-dimensional structure of phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis in the apo form and in complexes with coenzyme A and dephosphocoenzyme A

    Science.gov (United States)

    Timofeev, V. I.; Smirnova, E. A.; Chupova, L. A.; Esipov, R. S.; Kuranova, I. P.

    2012-01-01

    Crystals of phosphopantetheine adenylyltransferase (PPAT) from Mycobacterium tuberculosis in the apo form and in complexes with coenzyme A (PPAT/CoA) and dephosphocoenzyme A (PPAT/dPCoA) were grown in microgravity by the capillary counter-diffusion method. The structures of PPAT Mt in the apo form and in complexes with ligands were solved based on the X-ray diffraction data collected from the grown crystals. The crystal structures were refined at 1.76, 1.59, and 1.59 Å resolution to Rf factors of 0.175, 0.159, and 0.157 and Rfree of 0.224, 0.208, and 0.206 for PPAT, PPAT/CoA, and PPAT/dPCoA, respectively. The atomic coordinates of the structures were deposited in the Protein Data Bank (PDB ID: 3RFF, 3RHS, and 3RBA). In these structures, the ligand-binding sites were determined, the environment of these sites was characterized, and the conformational changes accompanying the ligand binding were analyzed.

  19. Three-dimensional structure of phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis in the apo form and in complexes with coenzyme A and dephosphocoenzyme A

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, V. I., E-mail: inna@ns.crys.ras.ru; Smirnova, E. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Chupova, L. A.; Esipov, R. S. [Russian Academy of Sciences, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Kuranova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2012-01-15

    Crystals of phosphopantetheine adenylyltransferase (PPAT) from Mycobacterium tuberculosis in the apo form and in complexes with coenzyme A (PPAT/CoA) and dephosphocoenzyme A (PPAT/dPCoA) were grown in microgravity by the capillary counter-diffusion method. The structures of PPAT Mt in the apo form and in complexes with ligands were solved based on the X-ray diffraction data collected from the grown crystals. The crystal structures were refined at 1.76, 1.59, and 1.59 Angstrom-Sign resolution to Rf factors of 0.175, 0.159, and 0.157 and Rfree of 0.224, 0.208, and 0.206 for PPAT, PPAT/CoA, and PPAT/dPCoA, respectively. The atomic coordinates of the structures were deposited in the Protein Data Bank (PDB ID: 3RFF, 3RHS, and 3RBA). In these structures, the ligand-binding sites were determined, the environment of these sites was characterized, and the conformational changes accompanying the ligand binding were analyzed.

  20. Quaternary organization in a bifunctional prokaryotic FAD synthetase: Involvement of an arginine at its adenylyltransferase module on the riboflavin kinase activity.

    Science.gov (United States)

    Serrano, Ana; Sebastián, María; Arilla-Luna, Sonia; Baquedano, Silvia; Pallarés, María Carmen; Lostao, Anabel; Herguedas, Beatriz; Velázquez-Campoy, Adrián; Martínez-Júlvez, Marta; Medina, Milagros

    2015-08-01

    Prokaryotic FAD synthetases (FADSs) are bifunctional enzymes composed of two modules, the C-terminal module with ATP:riboflavin kinase (RFK) activity, and the N-terminus with ATP:FMN adenylyltransferase (FMNAT) activity. The FADS from Corynebacterium ammoniagenes, CaFADS, forms transient oligomers during catalysis. These oligomers are stabilized by several interactions between the RFK and FMNAT sites from neighboring protomers, which otherwise are separated in the monomeric enzyme. Among these inter-protomer interactions, the salt bridge between E268 at the RFK site and R66 at the FMNAT-module is particularly relevant, as E268 is the catalytic base of the kinase reaction. Here we have introduced point mutations at R66 to analyze the impact of the salt-bridge on ligand binding and catalysis. Interestingly, these mutations have only mild effects on ligand binding and kinetic properties of the FMNAT-module (where R66 is located), but considerably impair the RFK activity turnover. Substitutions of R66 also modulate the ratio between monomeric and oligomeric species and modify the quaternary arrangement observed by single-molecule methods. Therefore, our data further support the cross-talk between the RFK- and FMNAT-modules of neighboring protomers in the CaFADS enzyme, and establish the participation of R66 in the modulation of the geometry of the RFK active site during catalysis.

  1. Independent transcription of glutamine synthetase (glnA2) and glutamine synthetase adenylyltransferase (glnE) in Mycobacterium bovis and Mycobacterium tuberculosis.

    Science.gov (United States)

    Hotter, Grant S; Mouat, Pania; Collins, Desmond M

    2008-09-01

    Mycobacterium bovis and Mycobacterium tuberculosis possess four glutamine synthetase homologues, two of which, glnA1 and glnA2, are required for virulence and are located on the bacterial chromosome on either side of glutamine synthetase adenylyltransferase (glnE). While glnA1 is encoded on the complementary strand, glnA2 is located 48bp upstream from glnE, raising the possibility that glnA2 and glnE may be co-transcribed. However, previous studies in M. bovis and M. tuberculosis have painted a contradictory picture of the (co)transcriptional status of glnA2 and glnE. Given the importance of the genes at the glnA1-glnE-glnA2 locus, we sought to clarify the transcriptional status of glnA2 and glnE in both M. bovis and M. tuberculosis. Reverse transcription-PCR demonstrated that glnA2 and glnE were independently transcribed in all six M. bovis and M. tuberculosis strains examined. Northern analysis of the glnA2 transcript in M. bovis AF2122/97 and M. tuberculosis H37Rv showed that it was monocistronic. These results predicted the presence of a glnE transcriptional start site in the glnA2-glnE intergenic region. An identical start site was confirmed in M. bovis AF2122/97 and M. tuberculosis H37Rv using 5' rapid amplification of cDNA ends. Typical mycobacterial -10 and -35 sequences are associated with this start site.

  2. Arabidopsis CDS blastp result: AK288092 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288092 J075185M21 At5g55810.1 68418.m06955 nicotinamide-nucleotide adenylyltransf...erase, putative / NAD(+) pyrophosphorylase, putative similar to nicotinamide mononucleotide adenylyl transfe

  3. Arabidopsis CDS blastp result: AK242265 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242265 J075185M21 At5g55810.1 68418.m06955 nicotinamide-nucleotide adenylyltransf...erase, putative / NAD(+) pyrophosphorylase, putative similar to nicotinamide mononucleotide adenylyl transfe

  4. Arabidopsis CDS blastp result: AK071224 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK071224 J023087B12 At5g55810.1 nicotinamide-nucleotide adenylyltransferase, putati...ve / NAD(+) pyrophosphorylase, putative similar to nicotinamide mononucleotide adenylyl transferase [Homo sa

  5. Action of nucleotide phosphotransferase of Escherichia coli on nicotinamide riboside and nicotinamide mononucleotide.

    Science.gov (United States)

    Brunngraber, E F; Chargaff, E

    1977-10-01

    The action of the nucleotide phosphotransferase of Escherichia coli on nicotinamide riboside and on its 5'-phosphate results in the addition of one phosphate moiety to each of the substrates. Although the proof is not conclusive, it is likely that the phosphate group is transferred to the 3'-hydroxyl of the ribose. This is in contrast to the behavior of the enzyme toward NAD in which only the adenylic acid portion is phosphorylated enzymically.

  6. IDENTIFICATION OF NICOTINAMIDE MONONUCLEOTIDE DEAMIDASE OF THE BACTERIAL PYRIDINE NUCLEOTIDE CYCLE REVEALS A NOVEL BROADLY CONSERVED AMIDOHYDROLASE FAMILY

    Energy Technology Data Exchange (ETDEWEB)

    Galeazzi, Luca; Bocci, Paolo; Amici, Adolfo; Brunetti, Lucia; Ruggieri, Silverio; Romine, Margaret F.; Reed, Samantha B.; Osterman, Andrei; Rodionov, Dmitry A.; Sorci, Leonardo; Raffaelli, Nadia

    2011-09-27

    The pyridine nucleotide cycle (PNC) is a network of salvage and recycling routes maintaining homeostasis of NAD(P) cofactor pool in the cell. Nicotinamide mononucleotide (NMN) deamidase (EC 3.5.1.42), one of the key enzymes of the bacterial PNC was originally described in Enterobacteria, but the corresponding gene eluded identification for over 30 years. A genomics-based reconstruction of NAD metabolism across hundreds bacterial species suggested that NMN deamidase reaction is the only possible way of nicotinamide salvage in the marine bacterium Shewanella oneidensis. This prediction was verified via purification of native NMN deamidase from S. oneidensis followed by the identification of the respective gene, termed pncC. Enzymatic characterization of the PncC protein, as well as phenotype analysis of deletion mutants, confirmed its proposed biochemical and physiological function in S. oneidensis. Of the three PncC homologs present in E. coli, NMN deamidase activity was confirmed only for the recombinant purified product of the ygaD gene. A comparative analysis at the level of sequence and three dimensional structure, which is available for one of the PncC family member, shows no homology with any previously described amidohydrolases. Multiple alignment analysis of functional and non functional PncC homologs, together with NMN docking experiments, allowed us to tentatively identify the active site area and conserved residues therein. An observed broad phylogenomic distribution of predicted functional PncCs in bacterial kingdom is consistent with a possible role in detoxification of NMN, resulting from NAD utilization by DNA ligase.

  7. Identification of Nicotinamide Mononucleotide Deamidase of the Bacterial Pyridine Nucleotide Cycle Reveals a Novel Broadly Conserved Amidohydrolase Family*

    Science.gov (United States)

    Galeazzi, Luca; Bocci, Paola; Amici, Adolfo; Brunetti, Lucia; Ruggieri, Silverio; Romine, Margaret; Reed, Samantha; Osterman, Andrei L.; Rodionov, Dmitry A.; Sorci, Leonardo; Raffaelli, Nadia

    2011-01-01

    The pyridine nucleotide cycle is a network of salvage and recycling routes maintaining homeostasis of NAD(P) cofactor pool in the cell. Nicotinamide mononucleotide (NMN) deamidase (EC 3.5.1.42), one of the key enzymes of the bacterial pyridine nucleotide cycle, was originally described in Enterobacteria, but the corresponding gene eluded identification for over 30 years. A genomics-based reconstruction of NAD metabolism across hundreds of bacterial species suggested that NMN deamidase reaction is the only possible way of nicotinamide salvage in the marine bacterium Shewanella oneidensis. This prediction was verified via purification of native NMN deamidase from S. oneidensis followed by the identification of the respective gene, termed pncC. Enzymatic characterization of the PncC protein, as well as phenotype analysis of deletion mutants, confirmed its proposed biochemical and physiological function in S. oneidensis. Of the three PncC homologs present in Escherichia coli, NMN deamidase activity was confirmed only for the recombinant purified product of the ygaD gene. A comparative analysis at the level of sequence and three-dimensional structure, which is available for one of the PncC family member, shows no homology with any previously described amidohydrolases. Multiple alignment analysis of functional and nonfunctional PncC homologs, together with NMN docking experiments, allowed us to tentatively identify the active site area and conserved residues therein. An observed broad phylogenomic distribution of predicted functional PncCs in the bacterial kingdom is consistent with a possible role in detoxification of NMN, resulting from NAD utilization by DNA ligase. PMID:21953451

  8. Identification of nicotinamide mononucleotide deamidase of the bacterial pyridine nucleotide cycle reveals a novel broadly conserved amidohydrolase family.

    Science.gov (United States)

    Galeazzi, Luca; Bocci, Paola; Amici, Adolfo; Brunetti, Lucia; Ruggieri, Silverio; Romine, Margaret; Reed, Samantha; Osterman, Andrei L; Rodionov, Dmitry A; Sorci, Leonardo; Raffaelli, Nadia

    2011-11-18

    The pyridine nucleotide cycle is a network of salvage and recycling routes maintaining homeostasis of NAD(P) cofactor pool in the cell. Nicotinamide mononucleotide (NMN) deamidase (EC 3.5.1.42), one of the key enzymes of the bacterial pyridine nucleotide cycle, was originally described in Enterobacteria, but the corresponding gene eluded identification for over 30 years. A genomics-based reconstruction of NAD metabolism across hundreds of bacterial species suggested that NMN deamidase reaction is the only possible way of nicotinamide salvage in the marine bacterium Shewanella oneidensis. This prediction was verified via purification of native NMN deamidase from S. oneidensis followed by the identification of the respective gene, termed pncC. Enzymatic characterization of the PncC protein, as well as phenotype analysis of deletion mutants, confirmed its proposed biochemical and physiological function in S. oneidensis. Of the three PncC homologs present in Escherichia coli, NMN deamidase activity was confirmed only for the recombinant purified product of the ygaD gene. A comparative analysis at the level of sequence and three-dimensional structure, which is available for one of the PncC family member, shows no homology with any previously described amidohydrolases. Multiple alignment analysis of functional and nonfunctional PncC homologs, together with NMN docking experiments, allowed us to tentatively identify the active site area and conserved residues therein. An observed broad phylogenomic distribution of predicted functional PncCs in the bacterial kingdom is consistent with a possible role in detoxification of NMN, resulting from NAD utilization by DNA ligase.

  9. Identification a novel mononucleotide deletion mutation in GAA in pompe disease patients

    Directory of Open Access Journals (Sweden)

    Milad Ebrahimi

    2017-01-01

    Full Text Available Background: Mutations in the acid alpha-glucosidase (GAA gene usually lead to reduced GAA activity. In this study, we analyzed the mutations of GAA and GAA enzyme activity from one sibling suspected Pompe disease and their first-degree relatives. Materials and Methods: In this cross-sectional study, GAA enzyme activity assay was assessed using tandem mass spectrometry. Polymerase chain reaction and Sanger sequencing were performed for GAA analysis. Results: GAA enzyme activity was significantly decreased in patients compared to the normal range (P = 0.02. Two individuals showed ten alterations in the GAA sequence, in which one of them (c. 1650del G has not been previously described in the literature. A single Guanine deletion (del-G was detected at codon 551 in exon 12. Conclusion: According to the literature, the detected change is a novel mutation. We hypothesized that the discovered deletion in the GAA might lead to a reduced activity of the gene product.

  10. Structural investigation of the biosynthesis of alternative lower ligands for cobamides by nicotinate mononucleotide: 5,6-dimethylbenzimidazole phosphoribosyltransferase from Salmonella enterica.

    Science.gov (United States)

    Cheong, C G; Escalante-Semerena, J C; Rayment, I

    2001-10-05

    Nicotinate mononucleotide (NaMN):5,6-dimethylbenzimidazole phosphoribosyltransferase (CobT) from Salmonella enterica plays a central role in the synthesis of alpha-ribazole, a key component of the lower ligand of cobalamin. Surprisingly, CobT can phosphoribosylate a wide range of aromatic substrates, giving rise to a wide variety of lower ligands in cobamides. To understand the molecular basis for this lack of substrate specificity, the x-ray structures of CobT complexed with adenine, 5-methylbenzimidazole, 5-methoxybenzimidazole, p-cresol, and phenol were determined. Furthermore, adenine, 5-methylbenzimidazole, 5-methoxybenzimidazole, and 2-hydroxypurine were observed to react with NaMN within the crystal lattice and undergo the phosphoribosyl transfer reaction to form product. Significantly, the stereochemistries of all products are identical to those found in vivo. Interestingly, p-cresol and phenol, which are the lower ligand in Sporomusa ovata, bound to CobT but did not react with NaMN. This study provides a structural explanation for how CobT can phosphoribosylate most of the commonly observed lower ligands found in cobamides with the exception of the phenolic lower ligands observed in S. ovata. This is accomplished with minor conformational changes in the side chains that constitute the 5,6-dimethylbenzimidazole binding site. These investigations are consistent with the implication that the nature of the lower ligand is controlled by metabolic factors rather by the specificity of the phosphoribosyltransferase.

  11. NadN and e (P4) are essential for utilization of NAD and nicotinamide mononucleotide but not nicotinamide riboside in Haemophilus influenzae.

    Science.gov (United States)

    Kemmer, G; Reilly, T J; Schmidt-Brauns, J; Zlotnik, G W; Green, B A; Fiske, M J; Herbert, M; Kraiss, A; Schlör, S; Smith, A; Reidl, J

    2001-07-01

    Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks almost all the biosynthetic enzymes necessary for the de novo synthesis of that cofactor. Factor V can be provided as either nicotinamide adenosine dinucleotide (NAD), nicotinamide mononucleotide (NMN), or nicotinamide riboside (NR) in vitro, but little is known about the source or the mechanism of uptake of these substrates in vivo. As shown by us earlier, at least two gene products are involved in the uptake of NAD, the outer membrane lipoprotein e (P4), which has phosphatase activity and is encoded by hel, and a periplasmic NAD nucleotidase, encoded by nadN. It has also been observed that the latter gene product is essential for H. influenzae growth on media supplemented with NAD. In this report, we describe the functions and substrates of these two proteins as they act together in an NAD utilization pathway. Data are provided which indicate that NadN harbors not only NAD pyrophosphatase but also NMN 5'-nucleotidase activity. The e (P4) protein is also shown to have NMN 5'-nucleotidase activity, recognizing NMN as a substrate and releasing NR as its product. Insertion mutants of nadN or deletion and site-directed mutants of hel had attenuated growth and a reduced uptake phenotype when NMN served as substrate. A hel and nadN double mutant was only able to grow in the presence of NR, whereas no uptake of NMN was observed.

  12. 细菌中黄素单核苷酸核糖开关研究进展%Research progress on Flavin mononucleotide riboswitch in bacteria

    Institute of Scientific and Technical Information of China (English)

    单战; 张凯; 郭江峰

    2014-01-01

    核糖开关(Riboswitch)具有RNA结构,是位于mRNA 5′非编码区的RNA传感器.在无任何蛋白质因子参与下,可特异性地直接结合代谢产物,使自身构象发生相应变化,启动或阻断mRNA的转录、翻译、拼接等过程来调控基因的表达.某些Riboswitch可应用于抗菌药物研发.本文综述了Flavin mononucleotide riboswitch (FMN riboswitch)三维结构、基因表达调控的机制及热力学、动力学的研究进展,为基于FMN riboswitch的合理药物设计奠定了基础,并对开发新一代抗菌药物进行了展望.

  13. Generation, Release, and Uptake of the NAD Precursor Nicotinic Acid Riboside by Human Cells.

    Science.gov (United States)

    Kulikova, Veronika; Shabalin, Konstantin; Nerinovski, Kirill; Dölle, Christian; Niere, Marc; Yakimov, Alexander; Redpath, Philip; Khodorkovskiy, Mikhail; Migaud, Marie E; Ziegler, Mathias; Nikiforov, Andrey

    2015-11-06

    NAD is essential for cellular metabolism and has a key role in various signaling pathways in human cells. To ensure proper control of vital reactions, NAD must be permanently resynthesized. Nicotinamide and nicotinic acid as well as nicotinamide riboside (NR) and nicotinic acid riboside (NAR) are the major precursors for NAD biosynthesis in humans. In this study, we explored whether the ribosides NR and NAR can be generated in human cells. We demonstrate that purified, recombinant human cytosolic 5'-nucleotidases (5'-NTs) CN-II and CN-III, but not CN-IA, can dephosphorylate the mononucleotides nicotinamide mononucleotide and nicotinic acid mononucleotide (NAMN) and thus catalyze NR and NAR formation in vitro. Similar to their counterpart from yeast, Sdt1, the human 5'-NTs require high (millimolar) concentrations of nicotinamide mononucleotide or NAMN for efficient catalysis. Overexpression of FLAG-tagged CN-II and CN-III in HEK293 and HepG2 cells resulted in the formation and release of NAR. However, NAR accumulation in the culture medium of these cells was only detectable under conditions that led to increased NAMN production from nicotinic acid. The amount of NAR released from cells engineered for increased NAMN production was sufficient to maintain viability of surrounding cells unable to use any other NAD precursor. Moreover, we found that untransfected HeLa cells produce and release sufficient amounts of NAR and NR under normal culture conditions. Collectively, our results indicate that cytosolic 5'-NTs participate in the conversion of NAD precursors and establish NR and NAR as integral constituents of human NAD metabolism. In addition, they point to the possibility that different cell types might facilitate each other's NAD supply by providing alternative precursors.

  14. Generation, Release, and Uptake of the NAD Precursor Nicotinic Acid Riboside by Human Cells*

    Science.gov (United States)

    Kulikova, Veronika; Shabalin, Konstantin; Nerinovski, Kirill; Dölle, Christian; Niere, Marc; Yakimov, Alexander; Redpath, Philip; Khodorkovskiy, Mikhail; Migaud, Marie E.; Ziegler, Mathias; Nikiforov, Andrey

    2015-01-01

    NAD is essential for cellular metabolism and has a key role in various signaling pathways in human cells. To ensure proper control of vital reactions, NAD must be permanently resynthesized. Nicotinamide and nicotinic acid as well as nicotinamide riboside (NR) and nicotinic acid riboside (NAR) are the major precursors for NAD biosynthesis in humans. In this study, we explored whether the ribosides NR and NAR can be generated in human cells. We demonstrate that purified, recombinant human cytosolic 5′-nucleotidases (5′-NTs) CN-II and CN-III, but not CN-IA, can dephosphorylate the mononucleotides nicotinamide mononucleotide and nicotinic acid mononucleotide (NAMN) and thus catalyze NR and NAR formation in vitro. Similar to their counterpart from yeast, Sdt1, the human 5′-NTs require high (millimolar) concentrations of nicotinamide mononucleotide or NAMN for efficient catalysis. Overexpression of FLAG-tagged CN-II and CN-III in HEK293 and HepG2 cells resulted in the formation and release of NAR. However, NAR accumulation in the culture medium of these cells was only detectable under conditions that led to increased NAMN production from nicotinic acid. The amount of NAR released from cells engineered for increased NAMN production was sufficient to maintain viability of surrounding cells unable to use any other NAD precursor. Moreover, we found that untransfected HeLa cells produce and release sufficient amounts of NAR and NR under normal culture conditions. Collectively, our results indicate that cytosolic 5′-NTs participate in the conversion of NAD precursors and establish NR and NAR as integral constituents of human NAD metabolism. In addition, they point to the possibility that different cell types might facilitate each other's NAD supply by providing alternative precursors. PMID:26385918

  15. Head to head comparison of short-term treatment with the NAD+ precursor nicotinamide mononucleotide (NMN and six weeks of exercise in obese female mice

    Directory of Open Access Journals (Sweden)

    Golam Mezbah Uddin

    2016-08-01

    Full Text Available Obesity is well known to be a major cause of several chronic metabolic diseases, which can be partially counteracted by exercise. This is due, in part, to an upregulation of mitochondrial activity through increased nicotinamide adenine dinucleotide (NAD+. Recent studies have shown that NAD+ levels can be increased by using the NAD+ precursor, nicotinamide mononucleotide (NMN leading to the suggestion that NMN could be a useful intervention in diet related metabolic disorders. In this study we compared the metabolic, and especially mitochondrial-associated, effects of exercise and NMN in ameliorating the consequences of high-fat diet (HFD induced obesity in mice. Sixty female 5 week old C57BL6/J mice were allocated across 5 interventions: Chow sedentary: CS; Chow exercise: CEX; HFD sedentary: HS; HFD NMN: HNMN; HFD exercise: HEX (12/group. After 6 weeks of diet, exercise groups underwent treadmill exercise (15 m/min for 45 minutes, 6 days per week for 6 weeks. NMN or vehicle (500 mg/kg body weight was injected (i.p. daily for the last 17 days. No significant alteration in body weight was observed in response to exercise or NMN. The HFD significantly altered adiposity, glucose tolerance, plasma insulin, NADH levels and citrate synthase activity in muscle and liver. HEX and HNMN groups both showed significantly improved glucose tolerance compared to the HS group. NAD+ levels were increased significantly both in muscle and liver by NMN whereas exercise increased NAD+ only in muscle. Both NMN and exercise ameliorated the HFD-induced reduction in liver citrate synthase activity. However, exercise, but not NMN, ameliorated citrate synthase activity in muscle. Overall these data suggest that while exercise and NMN-supplementation can induce similar reversal of the glucose intolerance induced by obesity, they are associated with tissue-specific effects and differential alterations to mitochondrial function in muscle and liver.

  16. Stimulation of nicotinamide adenine dinucleotide biosynthetic pathways delays axonal degeneration after axotomy.

    Science.gov (United States)

    Sasaki, Yo; Araki, Toshiyuki; Milbrandt, Jeffrey

    2006-08-16

    Axonal degeneration occurs in many neurodegenerative diseases and after traumatic injury and is a self-destructive program independent from programmed cell death. Previous studies demonstrated that overexpression of nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1) or exogenous application of nicotinamide adenine dinucleotide (NAD) can protect axons of cultured dorsal root ganglion (DRG) neurons from degeneration caused by mechanical or neurotoxic injury. In mammalian cells, NAD can be synthesized from multiple precursors, including tryptophan, nicotinic acid, nicotinamide, and nicotinamide riboside (NmR), via multiple enzymatic steps. To determine whether other components of these NAD biosynthetic pathways are capable of delaying axonal degeneration, we overexpressed each of the enzymes involved in each pathway and/or exogenously administered their respective substrates in DRG cultures and assessed their capacity to protect axons after axotomy. Among the enzymes tested, Nmnat1 had the strongest protective effects, whereas nicotinamide phosphoribosyl transferase and nicotinic acid phosphoribosyl transferase showed moderate protective activity in the presence of their substrates. Strong axonal protection was also provided by Nmnat3, which is predominantly located in mitochondria, and an Nmnat1 mutant localized to the cytoplasm, indicating that the subcellular location of NAD production is not crucial for protective activity. In addition, we showed that exogenous application of the NAD precursors that are the substrates of these enzymes, including nicotinic acid mononucleotide, nicotinamide mononucleotide, and NmR, can also delay axonal degeneration. These results indicate that stimulation of NAD biosynthetic pathways via a variety of interventions may be useful in preventing or delaying axonal degeneration.

  17. Stability characteristics and structural properties of single- and double-walled boron-nitride nanotubes under physical adsorption of Flavin mononucleotide (FMN) in aqueous environment using molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, R., E-mail: r_ansari@guilan.ac.ir; Ajori, S., E-mail: Shahram_ajori1366@yahoo.com; Ameri, A.

    2016-03-15

    Graphical abstract: Structural properties and stability characteristics of single- and double-walled boron-nitride nanotubes functionalized with Flavin mononucleotide (FMN) in aqueous environment are investigated employing molecular dynamics simulations. - Highlights: • Structural and buckling analysis of boron-nitride nanotubes under physical adsorption of Flavin mononucleotide (FMN). • Gyration radius increases linearly as the weight percentage of FMN increases. • Presence of water molecules results in more expansion of FMN around BNNTs. • Critical buckling force of functionalized BNNTs is higher than that of pure BNNTs. • The critical strain of functionalized BNNTs is found to be lower than that of pure ones. - Abstract: The non-cytotoxic properties of Boron-nitride nanotubes (BNNTs) and the ability of stable interaction with biomolecules make them so promising for biological applications. In this research, molecular dynamics (MD) simulations are performed to investigate the structural properties and stability characteristics of single- and double-walled BNNTs under physical adsorption of Flavin mononucleotide (FMN) in vacuum and aqueous environments. According to the simulation results, gyration radius increases by rising the weight percentage of FMN. Also, the results demonstrate that critical buckling force of functionalized BNNTs increases in vacuum. Moreover, it is observed that by increasing the weight percentage of FMN, critical force of functionalized BNNTs rises. By contrast, critical strain reduces by functionalization of BNNTs in vacuum. Considering the aqueous environment, it is observed that gyration radius and critical buckling force of functionalized BNNTs increase more considerably than those of functionalized BNNTs in vacuum, whereas the critical strains approximately remain unchanged.

  18. Association of erythrocyte acid phosphatase phenotypes with myopia

    Directory of Open Access Journals (Sweden)

    Himabindu P

    2005-01-01

    Full Text Available Acid phosphatase is a polymorphic nonspecific orthophosphate monoesterase which catalyses the cleaving of phosphoric acid and subsequent breakdown of several monophosphoric esters under acidic pH conditions. Acid phosphatase has a physiologic function as a flavin mononucleotide phosphatase (FMN and regulates the intracellular concentrations of flavin coenzymes that are electron carriers in the oxidative phosphorylation pathway. Myopia or nearsightedness is caused by both environmental and genetic factors. Myopic eyes when subjected to excessive oxidative stress results in retinal detachments .In the present study there is a significant elevation of AA phenotype in myopes when compared to controls. The AA phenotype is more susceptible to oxidative stress and its lower enzyme activity is known to be associated with increased intrauterine growth that further results in increased axial length in progressive myopia. The AA phenotype also confers risk for myopia development in males, early age group and cases with parental consanguinity.

  19. Recognition of nucleoside monophosphate substrates by Haemophilus influenzae class C acid phosphatase.

    Science.gov (United States)

    Singh, Harkewal; Schuermann, Jonathan P; Reilly, Thomas J; Calcutt, Michael J; Tanner, John J

    2010-12-10

    The e (P4) phosphatase from Haemophilus influenzae functions in a vestigial NAD(+) utilization pathway by dephosphorylating nicotinamide mononucleotide to nicotinamide riboside. P4 is also the prototype of class C acid phosphatases (CCAPs), which are nonspecific 5',3'-nucleotidases localized to the bacterial outer membrane. To understand substrate recognition by P4 and other class C phosphatases, we have determined the crystal structures of a substrate-trapping mutant P4 enzyme complexed with nicotinamide mononucleotide, 5'-AMP, 3'-AMP, and 2'-AMP. The structures reveal an anchor-shaped substrate-binding cavity comprising a conserved hydrophobic box that clamps the nucleotide base, a buried phosphoryl binding site, and three solvent-filled pockets that contact the ribose and the hydrogen-bonding edge of the base. The span between the hydrophobic box and the phosphoryl site is optimal for recognizing nucleoside monophosphates, explaining the general preference for this class of substrate. The base makes no hydrogen bonds with the enzyme, consistent with an observed lack of base specificity. Two solvent-filled pockets flanking the ribose are key to the dual recognition of 5'-nucleotides and 3'-nucleotides. These pockets minimize the enzyme's direct interactions with the ribose and provide sufficient space to accommodate 5' substrates in an anti conformation and 3' substrates in a syn conformation. Finally, the structures suggest that class B acid phosphatases and CCAPs share a common strategy for nucleotide recognition.

  20. Detection and identification of 1-methylethyl and methyl radicals generated by irradiating tea tree (Melaleuca alternifolia) oil with visible light (436 nm) in the presence of flavin mononucleotide and ferrous ion.

    Science.gov (United States)

    Mori, H-M; Iwahashi, H

    2013-08-01

    Here, we determined the electron spin resonance (ESR) spectra of standard reaction mixtures (I) containing 25 μM flavin mononucleotide (FMN), 0.018% tea tree (Melaleuca alternifolia) oil, 1.9 M acetonitrile, 20 mM phosphate buffer (pH 7.4), 0.1 M α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN), and 1.0 mM FeSO₄(NH₄)₂SO₄ irradiated with 436 nm visible light (7.8 J/cm²). Prominent ESR signals (αN = 1.58 mT and αHβ = 0.26 mT) were detected, suggesting that free radicals form in the standard reaction. In order to know whether singlet oxygen (¹O₂) is involved in the radical formation or not, ESR measurement was performed for the standard D₂O reaction mixture (I) which contained 25 μM FMN, 0.0036% tea tree oil, 1.9 M acetonitrile-d3, 20 mM phosphate buffer (pH 7.4), 0.1 M 4-POBN and 1.0 mM FeSO₄ in D₂O. The ESR peak height of the standard D₂O reaction increased to 169 ± 24% of the control. Thus, ¹O₂ seems to be involved in the formation of the radicals because D₂O increases the lifetime of singlet oxygen. High-performance liquid chromatography-ESR-mass spectrometry analyses detected 1-methylethyl and methyl radicals in the standard reaction. The radicals appear to form through the reaction of ferrous ion with α-terpinene endoperoxide (ascaridole), which generated from the reaction of α-terpinene with ¹O₂. The 1-methylethyl and methyl radicals may exert a pro-oxidant effect under these conditions.

  1. Oligomerization reactions of deoxyribonucleotides on montmorillonite clay - The effect of mononucleotide structure, phosphate activation and montmorillonite composition on phosphodiester bond formation

    Science.gov (United States)

    Ferris, James P.; KAMALUDDIN; Ertem, Gozen

    1990-01-01

    The 2(prime)-d-5(prime)-GMP and 2(prime)-d-5(prime)-AMP bind 2 times more strongly to montmorillonite 22A than do 2(prime)-d-5(prime)-CMP and 5(prime)-TMP. The dinucleotide d(pG)2 forms in 9.2 percent yield and the cyclic dinucleotide c(dpG)2 in 5.4 percent yield in the reaction of 2(prime)-d-5(prime)-GMP with EDAC in the presence of montmorillonite 22A. The yield of dimers which contain the phosphodiester bond decreases as the reaction medium is changed from 0.2 M NaCl to a mixture of 0.2 M NaCl and 0.075 M MgCl2. A low yield of d(pA)2 was observed in the condensation reaction of 5(prime)-ImdpA on montmorillonite 22A. The yield of d(pA)2 obtained when EDAC is used as the condensing agent increases with increasing iron content of the Na(+)-montmorillonite used as catalyst. Evidence is presented which shows that the acidity of the Na(+)-montmorillonite is a necessary but not sufficient factor for the montmorillonite catalysis of phosphodiester bond formation.

  2. Absence of SARM1 Rescues Development and Survival of NMNAT2-Deficient Axons

    OpenAIRE

    Jonathan Gilley; Giuseppe Orsomando; Isabel Nascimento-Ferreira; Michael P. Coleman

    2015-01-01

    Summary SARM1 function and nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) loss both promote axon degeneration, but their relative relationship in the process is unknown. Here, we show that NMNAT2 loss and resultant changes to NMNAT metabolites occur in injured SARM1-deficient axons despite their delayed degeneration and that axon degeneration specifically induced by NMNAT2 depletion requires SARM1. Strikingly, SARM1 deficiency also corrects axon outgrowth in mice lacking NMNAT2, i...

  3. Recognition of Nucleoside Monophosphate Substrates by Haemophilus influenzae Class C Acid Phosphatase

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Harkewal; Schuermann, Jonathan P.; Reilly, Thomas J.; Calcutt, Michael J.; Tanner, John J. (Cornell); (UMC)

    2010-12-08

    The e (P4) phosphatase from Haemophilus influenzae functions in a vestigial NAD{sup +} utilization pathway by dephosphorylating nicotinamide mononucleotide to nicotinamide riboside. P4 is also the prototype of class C acid phosphatases (CCAPs), which are nonspecific 5{prime},3{prime}-nucleotidases localized to the bacterial outer membrane. To understand substrate recognition by P4 and other class C phosphatases, we have determined the crystal structures of a substrate-trapping mutant P4 enzyme complexed with nicotinamide mononucleotide, 5{prime}-AMP, 3{prime}-AMP, and 2{prime}-AMP. The structures reveal an anchor-shaped substrate-binding cavity comprising a conserved hydrophobic box that clamps the nucleotide base, a buried phosphoryl binding site, and three solvent-filled pockets that contact the ribose and the hydrogen-bonding edge of the base. The span between the hydrophobic box and the phosphoryl site is optimal for recognizing nucleoside monophosphates, explaining the general preference for this class of substrate. The base makes no hydrogen bonds with the enzyme, consistent with an observed lack of base specificity. Two solvent-filled pockets flanking the ribose are key to the dual recognition of 5{prime}-nucleotides and 3{prime}-nucleotides. These pockets minimize the enzyme's direct interactions with the ribose and provide sufficient space to accommodate 5{prime} substrates in an anti conformation and 3{prime} substrates in a syn conformation. Finally, the structures suggest that class B acid phosphatases and CCAPs share a common strategy for nucleotide recognition.

  4. The Vitamin Nicotinamide: Translating Nutrition into Clinical Care

    Directory of Open Access Journals (Sweden)

    Zhao Zhong Chong

    2009-09-01

    Full Text Available Nicotinamide, the amide form of vitamin B3 (niacin, is changed to its mononucleotide compound with the enzyme nicotinic acide/nicotinamide adenylyltransferase, and participates in the cellular energy metabolism that directly impacts normal physiology. However, nicotinamide also influences oxidative stress and modulates multiple pathways tied to both cellular survival and death. During disorders that include immune system dysfunction, diabetes, and aging-related diseases, nicotinamide is a robust cytoprotectant that blocks cellular inflammatory cell activation, early apoptotic phosphatidylserine exposure, and late nuclear DNA degradation. Nicotinamide relies upon unique cellular pathways that involve forkhead transcription factors, sirtuins, protein kinase B (Akt, Bad, caspases, and poly (ADP-ribose polymerase that may offer a fine line with determining cellular longevity, cell survival, and unwanted cancer progression. If one is cognizant of the these considerations, it becomes evident that nicotinamide holds great potential for multiple disease entities, but the development of new therapeutic strategies rests heavily upon the elucidation of the novel cellular pathways that nicotinamide closely governs.

  5. The vitamin nicotinamide: translating nutrition into clinical care.

    Science.gov (United States)

    Maiese, Kenneth; Chong, Zhao Zhong; Hou, Jinling; Shang, Yan Chen

    2009-09-09

    Nicotinamide, the amide form of vitamin B(3) (niacin), is changed to its mononucleotide compound with the enzyme nicotinic acide/nicotinamide adenylyltransferase, and participates in the cellular energy metabolism that directly impacts normal physiology. However, nicotinamide also influences oxidative stress and modulates multiple pathways tied to both cellular survival and death. During disorders that include immune system dysfunction, diabetes, and aging-related diseases, nicotinamide is a robust cytoprotectant that blocks cellular inflammatory cell activation, early apoptotic phosphatidylserine exposure, and late nuclear DNA degradation. Nicotinamide relies upon unique cellular pathways that involve forkhead transcription factors, sirtuins, protein kinase B (Akt), Bad, caspases, and poly (ADP-ribose) polymerase that may offer a fine line with determining cellular longevity, cell survival, and unwanted cancer progression. If one is cognizant of the these considerations, it becomes evident that nicotinamide holds great potential for multiple disease entities, but the development of new therapeutic strategies rests heavily upon the elucidation of the novel cellular pathways that nicotinamide closely governs.

  6. NAD+ salvage pathway proteins suppress proteotoxicity in yeast models of neurodegeneration by promoting the clearance of misfolded/oligomerized proteins.

    Science.gov (United States)

    Ocampo, Alejandro; Liu, Jingjing; Barrientos, Antoni

    2013-05-01

    Increased levels of nicotinamide/nicotinic acid mononucleotide adenylyltransferase (NMNAT) act as a powerful suppressor of Wallerian degeneration and ataxin- and tau-induced neurodegeneration in flies and mice. However, the nature of the suppression mechanism/s remains controversial. Here, we show that in yeast models of proteinopathies, overexpression of the NMNAT yeast homologs, NMA1 and NMA2, suppresses polyglutamine (PolyQ) and α-synuclein-induced cytotoxicities. Unexpectedly, overexpression of other genes in the salvage pathway for NAD(+) biosynthesis, including QNS1, NPT1 and PNC1 also protected against proteotoxicity. Our data revealed that in all cases, this mechanism involves extensive clearance of the non-native protein. Importantly, we demonstrate that suppression by NMA1 does not require the presence of a functional salvage pathway for NAD(+) biosynthesis, SIR2 or an active mitochondrial oxidative phosphorylation (OXPHOS) system. Our results imply the existence of histone deacetylase- and OXPHOS-independent crosstalk between the proteins in the salvage pathway for NAD(+) biosynthesis and the proteasome that can be manipulated to achieve cellular protection against proteotoxic stress.

  7. Acidic deposition ("acid rain")

    Science.gov (United States)

    Schreiber, R. Kent; LaRoe, Edward T.; Farris, Gaye S.; Puckett, Catherine E.; Doran, Peter D.; Mac, Michael J.

    1995-01-01

    Acidic deposition, or "acid rain," describes any form of precipitation, including rain, snow, and fog, with a pH of 5.5 or below (Note: pH values below 7 are acidic; vinegar has a pH of 3). It often results when the acidity of normal precipitation is increased by sulfates and nitrates that are emitted into the atmosphere from burning fossil fuels. This form of airborne contamination is considered harmful, both directly and indirectly, to a host of plant and animal species.Although acid rain can fall virtually anywhere, ecological damages in environmentally sensitive areas downwind of industrial and urban emissions are a major concern. This includes areas that have a reduced capacity to neutralize acid inputs because of low alkalinity soils and areas that contain species with a low tolerance to acid conditions. To determine the distribution of acidic deposition and evaluate its biological effects, research and monitoring are being conducted by the federal government with support from states, universities, and private industry.            The national extent of the acid rain problem has been estimated by sampling water from 3,000 lakes and 500 streams (Irving 1991), representing more than 28,000 lakes and 56,000 stream reaches with a total of 200,000 km (125,000 mi). Some particularly sensitive areas, such as the Adirondack Mountain region, have been more intensively sampled and the biota examined in detail for effects from acidity.         To identify trends in aquatic ecosystems, present and historical survey data on water chemistry and associated biota are compared. In lakes, the chemical and biological history and pH trends may be inferred or reconstructed in some cases by examining assemblages of fossil diatoms and aquatic invertebrates in the sediment layers. In terrestrial ecosystems, vegetation damage is surveyed and effects of acidic deposition to plants and animals are determined from laboratory and field exposure experiments. Natural

  8. Valproic Acid

    Science.gov (United States)

    ... acid is in a class of medications called anticonvulsants. It works by increasing the amount of a ... older (about 1 in 500 people) who took anticonvulsants such as valproic acid to treat various conditions ...

  9. Amino acids

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002222.htm Amino acids To use the sharing features on this page, please enable JavaScript. Amino acids are organic compounds that combine to form proteins . ...

  10. Obeticholic Acid

    Science.gov (United States)

    Obeticholic acid is used alone or in combination with ursodiol (Actigall, Urso) to treat primary biliary cholangitis (PBC; a ... were not treated successfully with ursodiol alone. Obeticholic acid is in a class of medications called farnesoid ...

  11. Ascorbic Acid

    Science.gov (United States)

    Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C in ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops to ...

  12. Mefenamic Acid

    Science.gov (United States)

    Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. ...

  13. Acid mucopolysaccharides

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003368.htm Acid mucopolysaccharides To use the sharing features on this page, please enable JavaScript. Acid mucopolysaccharides is a test that measures the amount ...

  14. Ethacrynic Acid

    Science.gov (United States)

    Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

  15. Aminocaproic Acid

    Science.gov (United States)

    Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

  16. Aspartic acid

    Science.gov (United States)

    ... body work. It plays a role in: Hormone production and release Normal nervous system function Plant sources of aspartic acid include: avocado, asparagus, and molasses. Animal sources of aspartic acid include: ...

  17. Fatty acids - trans fatty acids

    Science.gov (United States)

    The data supporting a negative effect of dietary trans fatty acids on cardiovascular disease risk is consistent. The primary dietary sources of trans fatty acids include partially hydrogenated fat and rudiment fat. The adverse effect of trans fatty acids on plasma lipoprotein profiles is consisten...

  18. Metabolic profiling of alternative NAD biosynthetic routes in mouse tissues.

    Directory of Open Access Journals (Sweden)

    Valerio Mori

    Full Text Available NAD plays essential redox and non-redox roles in cell biology. In mammals, its de novo and recycling biosynthetic pathways encompass two independent branches, the "amidated" and "deamidated" routes. Here we focused on the indispensable enzymes gating these two routes, i.e. nicotinamide mononucleotide adenylyltransferase (NMNAT, which in mammals comprises three distinct isozymes, and NAD synthetase (NADS. First, we measured the in vitro activity of the enzymes, and the levels of all their substrates and products in a number of tissues from the C57BL/6 mouse. Second, from these data, we derived in vivo estimates of enzymes'rates and quantitative contributions to NAD homeostasis. The NMNAT activity, mainly represented by nuclear NMNAT1, appears to be high and nonrate-limiting in all examined tissues, except in blood. The NADS activity, however, appears rate-limiting in lung and skeletal muscle, where its undetectable levels parallel a relative accumulation of the enzyme's substrate NaAD (nicotinic acid adenine dinucleotide. In all tissues, the amidated NAD route was predominant, displaying highest rates in liver and kidney, and lowest in blood. In contrast, the minor deamidated route showed higher relative proportions in blood and small intestine, and higher absolute values in liver and small intestine. Such results provide the first comprehensive picture of the balance of the two alternative NAD biosynthetic routes in different mammalian tissues under physiological conditions. This fills a gap in the current knowledge of NAD biosynthesis, and provides a crucial information for the study of NAD metabolism and its role in disease.

  19. Folic Acid

    Science.gov (United States)

    ... damage. 10 Do I need folic acid after menopause? Yes. Women who have gone through menopause still need 400 micrograms of folic acid every ... United States: 2003–2006 . American Journal of Clinical Nutrition; 91(1): 231–237. Hamner, H.C., Cogswell, ...

  20. Determination of DNA adducts by combining acid-catalyzed hydrolysis and chromatographic analysis of the carcinogen-modified nucleobases.

    Science.gov (United States)

    Leung, Elvis M K; Deng, Kailin; Wong, Tin-Yan; Chan, Wan

    2016-01-01

    The commonly used method of analyzing carcinogen-induced DNA adducts involves the hydrolysis of carcinogen-modified DNA samples by using a mixture of enzymes, followed by (32)P-postlabeling or liquid chromatography (LC)-based analyses of carcinogen-modified mononucleotides/nucleosides. In the present study, we report the development and application of a new approach to DNA adduct analysis by combining the H(+)/heat-catalyzed release of carcinogen-modified nucleobases and the use of LC-based methods to analyze DNA adducts. Results showed that heating the carcinogen-modified DNA samples at 70 °C for an extended period of 4 to 6 h in the presence of 0.05% HCl can efficiently induce DNA depurination, releasing the intact carcinogen-modified nucleobases for LC analyses. After optimizing the hydrolysis conditions, DNA samples with C8- and N (2) -modified 2'-deoxyguanosine, as well as N (6) -modified 2'-deoxyadenosine, were synthesized by reacting DNA with 1-nitropyrene, acetaldehyde, and aristolochic acids, respectively. These samples were then hydrolyzed, and the released nucleobase adducts were analyzed using LC-based analytical methods. Analysis results demonstrated a dose-dependent release of target DNA adducts from carcinogen-modified DNA samples, indicating that the developed H(+)/heat-catalyzed hydrolysis method was quantitative. Comparative studies with enzymatic digestion method on carcinogen-modified DNA samples revealed that the two hydrolysis methods did not yield systematically different results.

  1. Biochemical characterization of quinolinic acid phosphoribosyltransferase from Mycobacterium tuberculosis H37Rv and inhibition of its activity by pyrazinamide.

    Directory of Open Access Journals (Sweden)

    Hyun Kim

    Full Text Available Quinolinic acid phosphoribosyltransferase (QAPRTase, EC 2.4.2.19 is a key enzyme in the de novo pathway of nicotinamide adenine dinucleotide (NAD biosynthesis and a target for the development of new anti-tuberculosis drugs. QAPRTase catalyzes the synthesis of nicotinic acid mononucleotide from quinolinic acid (QA and 5-phosphoribosyl-1-pyrophosphate (PRPP through a phosphoribosyl transfer reaction followed by decarboxylation. The crystal structure of QAPRTase from Mycobacterium tuberculosis H37Rv (MtQAPRTase has been determined; however, a detailed functional analysis of MtQAPRTase has not been published. Here, we analyzed the enzymatic activities of MtQAPRTase and determined the effect on catalysis of the anti-tuberculosis drug pyrazinamide (PZA. The optimum temperature and pH for MtQAPRTase activity were 60°C and pH 9.2. MtQAPRTase required bivalent metal ions and its activity was highest in the presence of Mg2+. Kinetic analyses revealed that the Km values for QA and PRPP were 0.08 and 0.39 mM, respectively, and the kcat values for QA and PRPP were 0.12 and 0.14 [s-1], respectively. When the amino acid residues of MtQAPRTase, which may interact with QA, were substituted with alanine residues, catalytic activity was undetectable. Further, PZA, which is an anti-tuberculosis drug and a structural analog of QA, markedly inhibited the catalytic activity of MtQAPRTase. The structure of PZA may provide the basis for the design of new inhibitors of MtQAPRTase. These findings provide new insights into the catalytic properties of MtQAPRTase.

  2. Conserved inhibitory mechanism and competent ATP binding mode for adenylyltransferases with Fic fold.

    Directory of Open Access Journals (Sweden)

    Arnaud Goepfert

    Full Text Available The ubiquitous FIC domain is evolutionarily conserved from bacteria to human and has been shown to catalyze AMP transfer onto protein side-chain hydroxyl groups. Recently, it was predicted that most catalytically competent Fic proteins are inhibited by the presence of an inhibitory helix αinh that is provided by a cognate anti-toxin (class I, or is part of the N- or C-terminal part of the Fic protein itself (classes II and III. In vitro, inhibition is relieved by mutation of a conserved glutamate of αinh to glycine. For the class III bacterial Fic protein NmFic from Neisseria meningitidis, the inhibitory mechanism has been elucidated. Here, we extend above study by including bacterial class I and II Fic proteins VbhT from Bartonella schoenbuchensis and SoFic from Shewanella oneidensis, respectively, and the respective E->G mutants. Comparative enzymatic and crystallographic analyses show that, in all three classes, the ATP substrate binds to the wild-type FIC domains, but with the α-phosphate in disparate and non-competent orientations. In the E->G mutants, however, the tri-phosphate moiety is found reorganized to the same tightly bound structure through a unique set of hydrogen bonds with Fic signature motif residues. The γ-phosphate adopts the location that is taken by the inhibitory glutamate in wild-type resulting in an α-phosphate orientation that can be attacked in-line by a target side-chain hydroxyl group. The latter is properly registered to the Fic active center by main-chain β-interactions with the β-hairpin flap. These data indicate that the active site motif and the exposed edge of the flap are both required to form an adenylylation-competent Fic protein.

  3. Folic acid

    Science.gov (United States)

    ... taking a specific nutritional supplement, containing vitamin B3 (nicotinamide), a compound isolated from grains (azelaic acid), zinc, ... lung cancer in most people. A type of skin cancer called melanoma. Limited research suggests that taking ...

  4. Folic Acid

    Science.gov (United States)

    ... B-complex vitamin needed by the body to manufacture red blood cells. A deficiency of this vitamin ... prepared from dried yeast, fruit, and fresh leafy green vegetables to increase the folic acid in your ...

  5. Ibotenic acid and thioibotenic acid

    DEFF Research Database (Denmark)

    Hermit, Mette B; Greenwood, Jeremy R; Nielsen, Birgitte

    2004-01-01

    with the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for thioibotenic acid....... These studies demonstrate how subtle differences in chemical structures can result in profound differences in pharmacological activity....

  6. Acid Rain

    Science.gov (United States)

    Bricker, Owen P.; Rice, Karen C.; Dietrich, W.E.; Sposito, Garrison

    1997-01-01

    Acid deposition, or acid rain as it is more commonly referred to, has become a widely publicized environmental issue in the U.S. over the past decade. The term usually conjures up images of fish kills, dying forests, "dead" lakes, and damage to monuments and other historic artifacts. The primary cause of acid deposition is emission of S02 and NOx to the atmosphere during the combustion of fossil fuels. Oxidation of these compounds in the atmosphere forms strong acids - H2SO4 and HNO3 - which are returned to the Earth in rain, snow, fog, cloud water, and as dry deposition.Although acid deposition has only recently been recognized as an environmental problem in the U.S., it is not a new phenomenon (Cogbill & Likens 1974). As early as the middle of the 17th century in England, the deleterious effects of industrial emissions on plants, animals, and humans, and the atmospheric transport of pollutants between England and France had become issues of concern (Evelyn 1661, Graunt 1662). It is interesting that well over three hundred years ago in England, recommendations were made to move industry outside of towns and build higher chimneys to spread the pollution into "distant parts." Increasing the height of smokestacks has helped alleviate local problems, but has exacerbated others. In the U.S. the height of the tallest smokestack has more than doubled, and the average height of smokestacks has tripled since the 1950s (Patrick et al 1981). This trend occurred in most industrialized nations during the 20th century and has had the effect of transforming acid rain from a local urban problem into a problem of global scale.

  7. Perfluorooctanoic acid

    NARCIS (Netherlands)

    de Voogt, P.; Wexler, P.

    2014-01-01

    Perfluorooctanoic acid (PFOA, 335-67-1) is used in fluoropolymer production and firefighting foams and persists in the environment. Human exposure to PFOA is mostly through the diet. PFOA primarily affects the liver and can cause developmental and reproductive toxic effects in test animals.

  8. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  9. Hydrofluoric acid poisoning

    Science.gov (United States)

    Fluorhydric acid ... stomach, or intestine have holes (perforations) from the acid. ... Hydrofluoric acid is especially dangerous. The most common accidents involving hydrofluoric acid cause severe burns on the skin ...

  10. Dehydroabietic acid

    Directory of Open Access Journals (Sweden)

    Xiao-Ping Rao

    2009-10-01

    Full Text Available The title compound [systematic name: (1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

  11. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    to the coastal sedimentary humic acids implying higher association of amino acids with the carbonaceous and fine grained sedimentary humic acids. Both the humic and fulvic acids are composed of neutral, acidic, basic, aromatic and sulphur containing amino acids....

  12. [Teichoic acids from lactic acid bacteria].

    Science.gov (United States)

    Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

    2012-01-01

    The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

  13. Plasma amino acids

    Science.gov (United States)

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  14. Uric acid test (image)

    Science.gov (United States)

    Uric acid urine test is performed to check for the amount of uric acid in urine. Urine is collected over a 24 ... testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

  15. POLYELEOSTEARIC ACID VESICLES

    Institute of Scientific and Technical Information of China (English)

    LI Zichen; XIE Ximng; FAN Qinghua; FANG Yifei

    1992-01-01

    α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solutionofeleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.

  16. Acid distribution in phosphoric acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Okae, I.; Seya, A.; Umemoto, M. [Fuji Electric Co., Ltd., Chiba (Japan)

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  17. Two for the Price of One: A Neuroprotective Chaperone Kit within NAD Synthase Protein NMNAT2

    Science.gov (United States)

    2016-01-01

    One of the most fascinating properties of the brain is the ability to function smoothly across decades of a lifespan. Neurons are nondividing mature cells specialized in fast electrical and chemical communication at synapses. Often, neurons and synapses operate at high levels of activity through sophisticated arborizations of long axons and dendrites that nevertheless stay healthy throughout years. On the other hand, aging and activity-dependent stress strike onto the protein machineries turning proteins unfolded and prone to form pathological aggregates associated with neurodegeneration. How do neurons protect from those insults and remain healthy for their whole life? Ali and colleagues now present a molecular mechanism by which the enzyme nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) acts not only as a NAD synthase involved in axonal maintenance but as a molecular chaperone helping neurons to overcome protein unfolding and protein aggregation. PMID:27454736

  18. Two for the Price of One: A Neuroprotective Chaperone Kit within NAD Synthase Protein NMNAT2.

    Directory of Open Access Journals (Sweden)

    Angela Lavado-Roldán

    2016-07-01

    Full Text Available One of the most fascinating properties of the brain is the ability to function smoothly across decades of a lifespan. Neurons are nondividing mature cells specialized in fast electrical and chemical communication at synapses. Often, neurons and synapses operate at high levels of activity through sophisticated arborizations of long axons and dendrites that nevertheless stay healthy throughout years. On the other hand, aging and activity-dependent stress strike onto the protein machineries turning proteins unfolded and prone to form pathological aggregates associated with neurodegeneration. How do neurons protect from those insults and remain healthy for their whole life? Ali and colleagues now present a molecular mechanism by which the enzyme nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2 acts not only as a NAD synthase involved in axonal maintenance but as a molecular chaperone helping neurons to overcome protein unfolding and protein aggregation.

  19. Gas-phase Acidities of Aspartic Acid, Glutamic Acid, and their Amino Acid Amides.

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhong; Matus, Myrna H; Velazquez, Hector A; Dixon, David A; Cassady, Carolyn J

    2007-02-14

    Gas-phase acidities (GA or ΔGacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage’s importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3–4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  20. Gas-phase acidities of aspartic acid, glutamic acid, and their amino acid amides

    Science.gov (United States)

    Li, Zhong; Matus, Myrna H.; Velazquez, Hector Adam; Dixon, David A.; Cassady, Carolyn J.

    2007-09-01

    Gas-phase acidities (GA or [Delta]Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage's importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3-4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  1. Toxicity of adipic acid.

    Science.gov (United States)

    Kennedy, Gerald L

    2002-05-01

    Adipic acid has very low acute toxicity in rats with an LD50 > 5000 mg/kg. Adipic acid produced mild to no skin irritation on intact guinea pig skin as a 50% concentration in propylene glycol; it was not a skin sensitizer. Adipic acid caused mild conjunctival irritation in washed rabbit eyes; in unwashed rabbit eyes, there was mild conjunctival irritation, minimal iritis, but no corneal effects. Adipic acid dust may irritate the mucous membranes of the lungs and nose. In a 2-year feeding study, rats fed adipic acid at concentrations up to 5% in the diet exhibited only weight loss. Adipic acid is not genetically active in a wide variety of assay systems. Adipic acid caused no developmental toxicity in mice, rats, rabbits, or hamsters when administered orally. Adipic acid is partially metabolized in humans; the balance is eliminated unchanged in the urine. Adipic acid is slightly to moderately toxic to fish, daphnia, and algae in acute tests.

  2. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Science.gov (United States)

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  3. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Science.gov (United States)

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  4. Omega-3 Fatty Acids

    Science.gov (United States)

    Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the ... the blood in people with very high triglycerides. Omega-3 fatty acids are in a class of ...

  5. Omega-6 Fatty Acids

    Science.gov (United States)

    Omega-6 fatty acids are types of fats. Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean oils. Other types of omega-6 fatty acids are found in black currant ...

  6. Lactic acid test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003507.htm Lactic acid test To use the sharing features on this page, please enable JavaScript. Lactic acid is mainly produced in muscle cells and red ...

  7. Catalytic Synthesis Lactobionic Acid

    Directory of Open Access Journals (Sweden)

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  8. Amino Acid Metabolism Disorders

    Science.gov (United States)

    ... this process. One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup urine disease. Amino acids are "building blocks" that join together to form ...

  9. Facts about Folic Acid

    Science.gov (United States)

    ... Partners About Us Information For… Media Policy Makers Facts About Folic Acid Language: English (US) Español ( ... a woman needs 400 micrograms (mcg) every day. Facts About Folic Acid Download and print this fact ...

  10. Azelaic Acid Topical

    Science.gov (United States)

    Azelaic acid gel and foam is used to clear the bumps, lesions, and swelling caused by rosacea (a skin ... redness, flushing, and pimples on the face). Azelaic acid cream is used to treat the pimples and ...

  11. Folic Acid Quiz

    Science.gov (United States)

    ... About Us Information For… Media Policy Makers Folic Acid Quiz Language: English (US) Español (Spanish) Recommend ... button beside the question. Good Luck! 1. Folic acid is: A a B vitamin B a form ...

  12. Immunoglobulin and fatty acids

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  13. The Acid Rain Reader.

    Science.gov (United States)

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  14. Stomach acid test

    Science.gov (United States)

    Gastric acid secretion test ... of the cells in the stomach to release acid. The stomach contents are then removed and analyzed. ... 3.5). These numbers are converted to actual acid production in units of milliequivalents per hour (mEq/ ...

  15. Acid Lipase Disease

    Science.gov (United States)

    ... Page You are here Home » Disorders » All Disorders Acid Lipase Disease Information Page Acid Lipase Disease Information Page What research is being ... research to understand lipid storage diseases such as acid lipase deficiency. Additional research studies hope to identify ...

  16. Acid Rain Study Guide.

    Science.gov (United States)

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  17. The Acid Rain Reader.

    Science.gov (United States)

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  18. Demospongic Acids Revisited

    Directory of Open Access Journals (Sweden)

    Gilles Barnathan

    2010-10-01

    Full Text Available The well-known fatty acids with a D5,9 unsaturation system were designated for a long period as demospongic acids, taking into account that they originally occurred in marine Demospongia sponges. However, such acids have also been observed in various marine sources with a large range of chain-lengths (C16–C32 and from some terrestrial plants with short acyl chains (C18–C19. Finally, the D5,9 fatty acids appear to be a particular type of non-methylene-interrupted fatty acids (NMA FAs. This article reviews the occurrence of these particular fatty acids in marine and terrestrial organisms and shows the biosynthetic connections between D5,9 fatty acids and other NMI FAs.

  19. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

  20. [Biosynthesis of adipic acid].

    Science.gov (United States)

    Han, Li; Chen, Wujiu; Yuan, Fei; Zhang, Yuanyuan; Wang, Qinhong; Ma, Yanhe

    2013-10-01

    Adipic acid is a six-carbon dicarboxylic acid, mainly for the production of polymers such as nylon, chemical fiber and engineering plastics. Its annual demand is close to 3 million tons worldwide. Currently, the industrial production of adipic acid is based on the oxidation of aromatics from non-renewable petroleum resources by chemo-catalytic processes. It is heavily polluted and unsustainable, and the possible alternative method for adipic acid production should be developed. In the past years, with the development of synthetic biology and metabolic engineering, green and clean biotechnological methods for adipic acid production attracted more attention. In this study, the research advances of adipic acid and its precursor production are reviewed, followed by addressing the perspective of the possible new pathways for adipic acid production.

  1. Boric acid and boronic acids inhibition of pigeonpea urease.

    Science.gov (United States)

    Reddy, K Ravi Charan; Kayastha, Arvind M

    2006-08-01

    Urease from the seeds of pigeonpea was competitively inhibited by boric acid, butylboronic acid, phenylboronic acid, and 4-bromophenylboronic acid; 4-bromophenylboronic acid being the strongest inhibitor, followed by boric acid > butylboronic acid > phenylboronic acid, respectively. Urease inhibition by boric acid is maximal at acidic pH (5.0) and minimal at alkaline pH (10.0), i.e., the trigonal planar B(OH)3 form is a more effective inhibitor than the tetrahedral B(OH)4 -anionic form. Similarly, the anionic form of phenylboronic acid was least inhibiting in nature.

  2. The biogeochemical cycle of the adsorbed template. II - Selective adsorption of mononucleotides on adsorbed polynucleotide templates

    Science.gov (United States)

    Lazard, Daniel; Lahav, Noam; Orenberg, James B.

    1988-01-01

    Experimental results are presented for the verification of the specific interaction step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The experimental system consisted of gypsum as the mineral to which an oligonucleotide template attaches (Poly-C or Poly-U) and (5-prime)-AMP, (5-prime)-GMP, (5-prime)-CMP and (5-prime)-UMP as the interacting biomonomers. When Poly-C or Poly-U were used as adsorbed templates, (5-prime)-GMP and (5-prime)-AMP, respectively, were observed to be the most strongly adsorbed species.

  3. Cyclic mononucleotide- and Clr-dependent gene regulation in Sinorhizobium meliloti.

    Science.gov (United States)

    Krol, Elizaveta; Klaner, Christina; Gnau, Petra; Kaever, Volkhard; Essen, Lars-Oliver; Becker, Anke

    2016-10-01

    To identify physiological processes affected by cAMP in the plant-symbiotic nitrogen-fixing α-proteobacterium Sinorhizobium meliloti Rm2011, cAMP levels were artificially increased by overexpression of its cognate adenylate/guanylate cyclase gene cyaJ. This resulted in high accumulation of cAMP in the culture supernatant, decreased swimming motility and increased production of succinoglycan, an exopolysaccharide involved in host invasion. Weaker, similar phenotypic changes were induced by overexpression of cyaB and cyaG1. Effects on swimming motility and succinoglycan production were partially dependent on clr encoding a cyclic AMP receptor-like protein. Transcriptome profiling of an cyaJ-overexpressing strain identified 72 upregulated and 82 downregulated genes. A considerable number of upregulated genes are related to polysaccharide biosynthesis and osmotic stress response. These included succinoglycan biosynthesis genes, genes of the putative polysaccharide synthesis nodP2-exoF3 cluster and feuN, the first gene of the operon encoding the FeuNPQ regulatory system. Downregulated genes were mostly related to respiration, central metabolism and swimming motility. Promoter-probe studies in the presence of externally added cAMP revealed 18 novel Clr-cAMP-regulated genes. Moreover, the addition of cGMP into the growth medium also promoted clr-dependent gene regulation. In vitro binding of Clr-cAMP and Clr-cGMP to the promoter regions of SMc02178, SMb20906,SMc04190, SMc00925, SMc01136 and cyaF2 required the DNA motif (A/C/T)GT(T/C)(T/C/A)C (N4) G(G/A)(T/A)ACA. Furthermore, SMc02178, SMb20906,SMc04190and SMc00653 promoters were activated by Clr-cAMP/cGMP in Escherichia coli as heterologous host. These findings suggest direct activation of these 7 genes by Clr-cAMP/cGMP.

  4. DNA strand transfer catalyzed by vaccinia topoisomerase: ligation of DNAs containing a 3' mononucleotide overhang.

    Science.gov (United States)

    Cheng, C; Shuman, S

    2000-05-01

    The specificity of vaccinia topoisomerase for transesterification to DNA at the sequence 5'-CCCTT and its versatility in strand transfer have illuminated the recombinogenic properties of type IB topoisomerases and spawned topoisomerase-based strategies for DNA cloning. Here we characterize a pathway of topoisomerase-mediated DNA ligation in which enzyme bound covalently to a CCCTT end with an unpaired +1T nucleotide rapidly and efficiently joins the CCCTT strand to a duplex DNA containing a 3' A overhang. The joining reaction occurs with high efficiency, albeit slowly, to duplex DNAs containing 3' G, T or C overhangs. Strand transfer can be restricted to the correctly paired 3' A overhang by including 0.5 M NaCl in the ligation reaction mixture. The effects of base mismatches and increased ionic strength on the rates of 3' overhang ligation provide a quantitative picture of the relative contributions of +1 T:A base pairing and electrostatic interactions downstream of the scissile phosphate to the productive binding of an unlinked acceptor DNA to the active site. The results clarify the biochemistry underlying topoisomerase-cloning of PCR products with non-templated 3' overhangs.

  5. The biogeochemical cycle of the adsorbed template. II - Selective adsorption of mononucleotides on adsorbed polynucleotide templates

    Science.gov (United States)

    Lazard, Daniel; Lahav, Noam; Orenberg, James B.

    1988-01-01

    Experimental results are presented for the verification of the specific interaction step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The experimental system consisted of gypsum as the mineral to which an oligonucleotide template attaches (Poly-C or Poly-U) and (5-prime)-AMP, (5-prime)-GMP, (5-prime)-CMP and (5-prime)-UMP as the interacting biomonomers. When Poly-C or Poly-U were used as adsorbed templates, (5-prime)-GMP and (5-prime)-AMP, respectively, were observed to be the most strongly adsorbed species.

  6. Acid-Base Homeostasis.

    Science.gov (United States)

    Hamm, L Lee; Nakhoul, Nazih; Hering-Smith, Kathleen S

    2015-12-07

    Acid-base homeostasis and pH regulation are critical for both normal physiology and cell metabolism and function. The importance of this regulation is evidenced by a variety of physiologic derangements that occur when plasma pH is either high or low. The kidneys have the predominant role in regulating the systemic bicarbonate concentration and hence, the metabolic component of acid-base balance. This function of the kidneys has two components: reabsorption of virtually all of the filtered HCO3(-) and production of new bicarbonate to replace that consumed by normal or pathologic acids. This production or generation of new HCO3(-) is done by net acid excretion. Under normal conditions, approximately one-third to one-half of net acid excretion by the kidneys is in the form of titratable acid. The other one-half to two-thirds is the excretion of ammonium. The capacity to excrete ammonium under conditions of acid loads is quantitatively much greater than the capacity to increase titratable acid. Multiple, often redundant pathways and processes exist to regulate these renal functions. Derangements in acid-base homeostasis, however, are common in clinical medicine and can often be related to the systems involved in acid-base transport in the kidneys.

  7. Glycolic Acid 15% Plus Salicylic Acid 2%

    Science.gov (United States)

    Sánchez-Blanco, Elena

    2011-01-01

    Background: Facial flat warts are a contagious viral disease that can cause disturbing cosmetic problems. Topical glycolic acid has been reported to be effective in dermatological treatment depending on the exfoliant capacity, but has not often been reported to be effective in the treatment of facial flat warts. Objective: The aim of this paper was to evaluate the efficacy and safety of glycolic acid 15% topical gel plus salicylic acid 2% in the treatment of recalcitrant facial flat warts. Methods: A total of 20 consecutive patients 7 to 16 years of age with recalcitrant facial flat warts were enrolled in this study. Patients having warts by the eye and lip regions were excluded from the study. A fine layer of face gel was applied to the treatment area once daily. Most of the participants had tried different treatments with no success. Assessments for the response and the occurrence of side effects were performed every two weeks at Weeks 2, 4, 6, and 8. Results: All the patients were clinically cured within eight weeks. Seven patients cleared in four weeks, and 13 patients cleared in eight weeks. No noticeable adverse events were related to the skin. Conclusion: Topical gel of glycolic acid 15% plus salicylic acid 2% is safe and effective when applied to facial flat warts once daily until clearance and may be considered as first-line treatment. PMID:21938272

  8. Nitrogen Lewis Acids.

    Science.gov (United States)

    Pogoreltsev, Alla; Tulchinsky, Yuri; Fridman, Natalia; Gandelman, Mark

    2017-03-22

    Being a major conception of chemistry, Lewis acids have found countless applications throughout chemical enterprise. Although many chemical elements can serve as the central atom of Lewis acids, nitrogen is usually associated with Lewis bases. Here, we report on the first example of robust and modifiable Lewis acids centered on the nitrogen atom, which provide stable and well-characterized adducts with various Lewis bases. On the basis of the reactivity of nitrogen Lewis acids, we prepared, for the first time, cyclic triazanes, a class of cyclic organic compounds sequentially bearing three all-saturated nitrogen atoms (N-N-N motif). Reactivity abilities of these N-Lewis acids were explained by theoretical calculations. Properties and future applications of nitrogen Lewis acids are intriguing.

  9. Citric Acid Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Lewis, Pattie L. (Compiler)

    2013-01-01

    The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

  10. USGS Tracks Acid Rain

    Science.gov (United States)

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  11. Parenteral Nutrition: Amino Acids

    Science.gov (United States)

    Hoffer, Leonard John

    2017-01-01

    There is growing interest in nutrition therapies that deliver a generous amount of protein, but not a toxic amount of energy, to protein-catabolic critically ill patients. Parenteral amino acids can achieve this goal. This article summarizes the biochemical and nutritional principles that guide parenteral amino acid therapy, explains how parenteral amino acid solutions are formulated, and compares the advantages and disadvantages of different parenteral amino acid products with enterally-delivered whole protein products in the context of protein-catabolic critical illness. PMID:28287411

  12. Parenteral Nutrition: Amino Acids.

    Science.gov (United States)

    Hoffer, Leonard John

    2017-03-10

    There is growing interest in nutrition therapies that deliver a generous amount of protein, but not a toxic amount of energy, to protein-catabolic critically ill patients. Parenteral amino acids can achieve this goal. This article summarizes the biochemical and nutritional principles that guide parenteral amino acid therapy, explains how parenteral amino acid solutions are formulated, and compares the advantages and disadvantages of different parenteral amino acid products with enterally-delivered whole protein products in the context of protein-catabolic critical illness.

  13. Diterpenoid acids from Grindelia nana.

    Science.gov (United States)

    Mahmoud, A A; Ahmed, A A; Tanaka, T; Iinuma, M

    2000-03-01

    Two new norditerpenoid acids of the labdane-type (norgrindelic acids), 4,5-dehydro-6-oxo-18-norgrindelic acid (1) and 4beta-hydroxy-6-oxo-19-norgrindelic acid (2), as well as a new grindelic acid derivative, 18-hydroxy-6-oxogrindelic acid (3), were isolated from the aerial parts of Grindelia nana. In addition, the known compounds, 6-oxogrindelic acid, grindelic acid, methyl grindeloate, 7alpha,8alpha-epoxygrindelic acid, and 4alpha-carboxygrindelic acid were also isolated. The structures of the new compounds were characterized on the basis of spectroscopic analysis.

  14. Nucleic Acid Immunity.

    Science.gov (United States)

    Hartmann, G

    2017-01-01

    Organisms throughout biology need to maintain the integrity of their genome. From bacteria to vertebrates, life has established sophisticated mechanisms to detect and eliminate foreign genetic material or to restrict its function and replication. Tremendous progress has been made in the understanding of these mechanisms which keep foreign or unwanted nucleic acids from viruses or phages in check. Mechanisms reach from restriction-modification systems and CRISPR/Cas in bacteria and archaea to RNA interference and immune sensing of nucleic acids, altogether integral parts of a system which is now appreciated as nucleic acid immunity. With inherited receptors and acquired sequence information, nucleic acid immunity comprises innate and adaptive components. Effector functions include diverse nuclease systems, intrinsic activities to directly restrict the function of foreign nucleic acids (e.g., PKR, ADAR1, IFIT1), and extrinsic pathways to alert the immune system and to elicit cytotoxic immune responses. These effects act in concert to restrict viral replication and to eliminate virus-infected cells. The principles of nucleic acid immunity are highly relevant for human disease. Besides its essential contribution to antiviral defense and restriction of endogenous retroelements, dysregulation of nucleic acid immunity can also lead to erroneous detection and response to self nucleic acids then causing sterile inflammation and autoimmunity. Even mechanisms of nucleic acid immunity which are not established in vertebrates are relevant for human disease when they are present in pathogens such as bacteria, parasites, or helminths or in pathogen-transmitting organisms such as insects. This review aims to provide an overview of the diverse mechanisms of nucleic acid immunity which mostly have been looked at separately in the past and to integrate them under the framework nucleic acid immunity as a basic principle of life, the understanding of which has great potential to

  15. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  16. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  17. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  18. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from...

  19. Carbolic acid poisoning

    Science.gov (United States)

    ... you to. If the person swallowed the carbolic acid, give them water or milk right away, if a provider tells ... well someone does depends on how much carbolic acid they swallowed and how quickly they receive treatment. The faster medical help is given, the better ...

  20. Uric acid - blood

    Science.gov (United States)

    ... High levels of uric acid can sometimes cause gout or kidney disease. You may have this test if you have had or are about to have certain types of chemotherapy. Rapid weight loss, which may occur with such treatments, can increase the amount of uric acid in ...

  1. Neurotoxicity of Folic Acid

    NARCIS (Netherlands)

    Amsterdam van JGC; Jansen EHJM; A Opperhuizen; TOX

    2004-01-01

    The present review summarises the neurotoxicological effects of folic acid. Some studies in animals have shown that folic acid is neurotoxic and epileptogenic when applied directly to the brain. One poorly controlled and not further reproduced study from 1970 reported neurotoxic symptoms like

  2. Amino Acid Crossword Puzzle

    Science.gov (United States)

    Sims, Paul A.

    2011-01-01

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

  3. Fats and fatty acids

    Science.gov (United States)

    The absolute fat requirement of the human species is the amount of essential fatty acids needed to maintain optimal fatty acid composition of all tissues and normal eicosanoid synthesis. At most, this requirement is no more than about 5% of an adequate energy intake. However, fat accounts for appro...

  4. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  5. Chlorogenic acid and caffeic acid are absorbed in humans

    OpenAIRE

    2001-01-01

    Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the absorption of chlorogenic acid and caffeic acid in humans are lacking. We determined the absorption of chlorogenic acid and caffeic acid in a cross-over study with 4 female and 3 male healthy ileo...

  6. Chlorogenic acid and caffeic acid are absorbed in humans

    NARCIS (Netherlands)

    Olthof, M.R.; Hollman, P.C.H.; Katan, M.B.

    2001-01-01

    Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the

  7. Chlorogenic acid and caffeic acid are absorbed in humans

    NARCIS (Netherlands)

    Olthof, M.R.; Hollman, P.C.H.; Katan, M.B.

    2001-01-01

    Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phenolic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of cardiovascular disease. However, data on the

  8. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also......, chlorinated lipids have been found in meat exposed to hypochlorite disinfected water, and in chlorine-treated flour and in products made from such flour. Following exposure to chlorine bleached pulp mill effluents, aquatic organisms may have elevated concentrations of chlorinated fatty acids in their lipids....... However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods...

  9. Phenolic acids enzymatic lipophilization.

    Science.gov (United States)

    Figueroa-Espinoza, Maria-Cruz; Villeneuve, Pierre

    2005-04-20

    Lipophilization is the esterification of a lipophilic moiety (fatty acid or fatty alcohol) on different substrates (phenolic acid, sugar, protein, ...), resulting in new molecules with modified hydrophilic/lipophilic balance. This reaction can be obtained chemically or enzymatically using different enzymes. Phenolic acids possess interesting biological properties (antioxidant, chelator, free radical scavenger, UV filter, antimicrobial, ...), but because of their relatively low solubility in aprotic media, their application in oil-based products is limited. Therefore, the esterification of their carboxylic acid function with a fatty alcohol enhances their hydrophobicity and results in a multifunctional amphiphilic molecule. Enzymatic lipophilization of phenolic acids is nowadays studied for potential industrial applications. Different systems have been proposed to perform the reaction yield [free or immobilized enzymes (lipase, feruloyl esterase, tannase, etc.), free or added organic solvent, addition of surfactant, microemulsion system, etc.]. Some of the functional properties of these esters have been demonstrated. This review presents a panorama of the advances in this field.

  10. 2-Methylaspartic acid monohydrate

    Directory of Open Access Journals (Sweden)

    Ray J. Butcher

    2013-12-01

    Full Text Available The title compound, C5H9NO4·H2O, is an isomer of the α-amino acid glutamic acid that crystallizes from water in its zwitterionic form as a monohydrate. It is not one of the 20 proteinogenic α-amino acids that are used in living systems and differs from the natural amino acids in that it has an α-methyl group rather than an α-H atom. In the crystal, an O—H...O hydrogen bond is present between the acid and water molecules while extensive N—H...O and O—H...O hydrogen bonds link the components into a three-dimensional array.

  11. Composition of amino acids, fatty acids and dietary fibre monomers ...

    African Journals Online (AJOL)

    Composition of amino acids, fatty acids and dietary fibre monomers in kernels of ... Nuts are rich in protein and essential amino acids, and have a high energy value ... of protein, especially when combined with foods with high lysine content.

  12. Amino acids analysis during lactic acid fermentation by single strain ...

    African Journals Online (AJOL)

    SAM

    2014-07-09

    Jul 9, 2014 ... of the three LAB strains to utilize amino acids for growth and lactic acid production were employed to ... Lactic acid bacteria (LAB), which are used for the ..... and characterization of potential probiotic lactobacilli from pig feces.

  13. Trans Fatty Acids

    Science.gov (United States)

    Doyle, Ellin

    1997-09-01

    Fats and their various fatty acid components seem to be a perennial concern of nutritionists and persons concerned with healthful diets. Advice on the consumption of saturated, polyunsaturated, monounsaturated, and total fat bombards us from magazines and newspapers. One of the newer players in this field is the group of trans fatty acids found predominantly in partially hydrogenated fats such as margarines and cooking fats. The controversy concerning dietary trans fatty acids was recently addressed in an American Heart Association (AHA) science advisory (1) and in a position paper from the American Society of Clinical Nutrition/American Institute of Nutrition (ASCN/AIN) (2). Both reports emphasize that the best preventive strategy for reducing risk for cardiovascular disease and some types of cancer is a reduction in total and saturated fats in the diet, but a reduction in the intake of trans fatty acids was also recommended. Although the actual health effects of trans fatty acids remain uncertain, experimental evidence indicates that consumption of trans fatty acids adversely affects serum lipid levels. Since elevated levels of serum cholesterol and triacylglycerols are associated with increased risk of cardiovascular disease, it follows that intake of trans fatty acids should be minimized.

  14. Gluconic acid production.

    Science.gov (United States)

    Anastassiadis, Savas; Morgunov, Igor G

    2007-01-01

    Gluconic acid, the oxidation product of glucose, is a mild neither caustic nor corrosive, non toxic and readily biodegradable organic acid of great interest for many applications. As a multifunctional carbonic acid belonging to the bulk chemicals and due to its physiological and chemical characteristics, gluconic acid itself, its salts (e.g. alkali metal salts, in especially sodium gluconate) and the gluconolactone form have found extensively versatile uses in the chemical, pharmaceutical, food, construction and other industries. Present review article presents the comprehensive information of patent bibliography for the production of gluconic acid and compares the advantages and disadvantages of known processes. Numerous manufacturing processes are described in the international bibliography and patent literature of the last 100 years for the production of gluconic acid from glucose, including chemical and electrochemical catalysis, enzymatic biocatalysis by free or immobilized enzymes in specialized enzyme bioreactors as well as discontinuous and continuous fermentation processes using free growing or immobilized cells of various microorganisms, including bacteria, yeast-like fungi and fungi. Alternatively, new superior fermentation processes have been developed and extensively described for the continuous and discontinuous production of gluconic acid by isolated strains of yeast-like mold Aureobasidium pullulans, offering numerous advantages over the traditional discontinuous fungi processes.

  15. Sulfuric Acid on Europa

    Science.gov (United States)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer.Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  16. Fusidic acid in dermatology

    DEFF Research Database (Denmark)

    Schöfer, Helmut; Simonsen, Lene

    1995-01-01

    efficacy and tolerability. Similarly, plain fusidic acid cream or ointment used two or three times daily in SSTIs such as impetigo are clinically and bacteriologically effective, with minimal adverse events. Combination formulations of fusidic acid with 1% hydrocortisone or 0.1% betamethasone achieve...... excellent results in infected eczema by addressing both inflammation and infection. A new lipid-rich combination formulation provides an extra moisturizing effect. Development of resistance to fusidic acid has remained generally low or short-lived and can be minimized by restricting therapy to no more than...

  17. Acid rain: An overview

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary of the effects of acid rain and related processes, sources, issues, corrective actions, research, current law, potential solutions, political solutions,...

  18. Fatty Acid Oxidation Disorders

    Science.gov (United States)

    ... acid oxidation disorders are tested for in newborn screening? The March of Dimes recommends that all babies ... in behavior Diarrhea, nausea (feeling sick to your stomach) and throwing up Drowsiness Fever Fussiness Little appetite ...

  19. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures....... The aziridino amides 43 and 51 were reductively cleaved with hydrazine to give 3-amino-2,3-dideoxyhexonhydrazides 83 and 85, which were easily converted into the corresponding lactone 84 and acid 86. The aziridine ring of 43 and 51 was also opened with acetic acid to give the 3-amino-3-deoxyhexonic acids 79...... and 82, respectively. The aminolactone 84 was converted into the corresponding amino sugar 89.With the aim of synthesising substrates for the Pictet-Spengler reaction three 4-aldehydo acetamidodideoxytetronolactones 92, 97 and 103 were prepared by periodate cleavage of the corresponding hexonolactones...

  20. [Hydrofluoric acid burns].

    Science.gov (United States)

    Holla, Robin; Gorter, Ramon R; Tenhagen, Mark; Vloemans, A F P M Jos; Breederveld, Roelf S

    2016-01-01

    Hydrofluoric acid is increasingly used as a rust remover and detergent. Dermal contact with hydrofluoric acid results in a chemical burn characterized by severe pain and deep tissue necrosis. It may cause electrolyte imbalances with lethal consequences. It is important to identify high-risk patients. 'High risk' is defined as a total affected body area > 3% or exposure to hydrofluoric acid in a concentration > 50%. We present the cases of three male patients (26, 31, and 39 years old) with hydrofluoric acid burns of varying severity and describe the subsequent treatments. The application of calcium gluconate 2.5% gel to the skin is the cornerstone of the treatment, reducing pain as well as improving wound healing. Nails should be thoroughly inspected and possibly removed if the nail is involved, to ensure proper healing. In high-risk patients, plasma calcium levels should be evaluated and cardiac monitoring is indicated.

  1. Azetidinic amino acids

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... of two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...... beta-amino alcohols through a straightforward five step sequence. The key step of this synthesis is an original anionic 4-exo-tet ring closure that forms the azetidine ring upon an intramolecular Michael addition. This reaction was proven to be reversible and to lead to a thermodynamic distribution...

  2. Amino acid racemisation dating

    Energy Technology Data Exchange (ETDEWEB)

    Murray-Wallace, C.V. [University of Wollongong, Wollongong, NSW (Australia). School of Geosciences

    1999-11-01

    The potential of the time-dependent amino acid racemisation reaction as a method of age assessment was first reported by Hare and Abelson (1968). They noted that in specimens of the bivalve mollusc Mercenaria sp., greater concentrations of amino acids in the D-configuration with increasing fossil age. Hare and Abelson (1968) also reported negligible racemisation in a modern specimen of Mecanaria sp. On this basis they suggested that the extent of amino acid racemisation (epimerisation in the case of isoleucine) may be used to assess the age of materials within and beyond the range of radiocarbon dating. For the past thirty years amino acid racemisation has been extensively applied in Quaternary research as a method of relative and numeric dating, and a particularly large literature has emerged on the subject 12 refs.

  3. Folic acid - test

    Science.gov (United States)

    ... folic acid before and during pregnancy helps prevent neural tube defects, such as spina bifida. Women who are ... take more if they have a history of neural tube defects in earlier pregnancies. Ask your provider how ...

  4. Amino Acids and Chirality

    Science.gov (United States)

    Cook, Jamie E.

    2012-01-01

    Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

  5. Ethylenediaminetetraacetic acid in endodontics

    OpenAIRE

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-01-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for...

  6. Bile acid sequestrants

    DEFF Research Database (Denmark)

    Hansen, Morten; Sonne, David P; Knop, Filip K

    2014-01-01

    Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid an......-lowering effect in patients with type 2 diabetes remain unclear. This article offers a review of the mechanisms behind the glucose-lowering effect of BASs, and the efficacy of BASs in the treatment of type 2 diabetes....... of the enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose...... and glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption...

  7. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles...

  8. Neutron Nucleic Acid Crystallography.

    Science.gov (United States)

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination.

  9. Performance Comparison of New Combinations of Acids with Mud Acid in Sandstone Acidizing

    Directory of Open Access Journals (Sweden)

    Mian Umer Shafiq

    2014-01-01

    Full Text Available The aim of this research is to find the best suitable acid to acidize undamaged low permeable sandstone formation Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50 to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid- Hydrofluoric with Concentration (3% HF-12% HCl. This study presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results analyzed are porosity, permeability, strength, color change and FESEM Analysis. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  10. Acidification and Acid Rain

    Science.gov (United States)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  11. Inhibitory effect of ethanol, acetic acid, propionic acid and butyric acid on fermentative hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bo; Wan, Wei; Wang, Jianlong [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China)

    2008-12-15

    The inhibitory effect of added ethanol, acetic acid, propionic acid and butyric acid on fermentative hydrogen production by mixed cultures was investigated in batch tests using glucose as substrate. The experimental results showed that, at 35 C and initial pH 7.0, during the fermentative hydrogen production, the substrate degradation efficiency, hydrogen production potential, hydrogen yield and hydrogen production rate all trended to decrease with increasing added ethanol, acetic acid, propionic acid and butyric acid concentration from 0 to 300 mmol/L. The inhibitory effect of added ethanol on fermentative hydrogen production was smaller than those of added acetic acid, propionic acid and butyric acid. The modified Han-Levenspiel model could describe the inhibitory effects of added ethanol, acetic acid, propionic acid and butyric acid on fermentative hydrogen production rate in this study successfully. The modified Logistic model could describe the progress of cumulative hydrogen production. (author)

  12. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  13. EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Qi-dao Chen; Bing Wu; Xiao-yin Hong

    1999-01-01

    By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.

  14. Determination of Sialic Acids by Acidic Ninhydrin Reaction

    Directory of Open Access Journals (Sweden)

    Yao,Kenzabroh

    1987-12-01

    Full Text Available A new acidic ninhydrin method for determining free sialic acids is described. The method is based on the reaction of sialic acids with Gaitonde's acid ninhydrin reagent 2 which yields a stable color with an absorption maximum at 470 nm. The standard curve is linear in the range of 5 to 500 nmol of N-acetylneuraminic acid per 0.9 ml of reaction mixture. The reaction was specific only for sialic acids among the various sugars and sugar derivatives examined. Some interference of this method by cysteine, cystine and tryptophan was noted, although their absorption maxima differed from that of sialic acids. The interference by these amino acids was eliminated with the use of a small column of cation-exchange resin. The acidic ninhydrin method provides a simple and rapid method for the determination of free sialic acids in biological materials.

  15. Domoic Acid Epileptic Disease

    Directory of Open Access Journals (Sweden)

    John S. Ramsdell

    2014-03-01

    Full Text Available Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis.

  16. Hydrogen production by fermentation using acetic acid and lactic acid.

    Science.gov (United States)

    Matsumoto, Mitsufumi; Nishimura, Yasuhiko

    2007-03-01

    Microbial hydrogen production from sho-chu post-distillation slurry solution (slurry solution) containing large amounts of organic acids was investigated. The highest hydrogen producer, Clostridium diolis JPCC H-3, was isolated from natural environment and produced hydrogen at 6.03+/-0.15 ml from 5 ml slurry solution in 30 h. Interestingly, the concentration of acetic acid and lactic acid in the slurry solution decreased during hydrogen production. The substrates for hydrogen production by C. diolis JPCC H-3, in particular organic acids, were investigated in an artificial medium. No hydrogen was produced from acetic acid, propionic acid, succinic acid, or citric acid on their own. Hydrogen and butyric acid were produced from a mixture of acetic acid and lactic acid, showing that C. diolis. JPCC H-3 could produce hydrogen from acetic acid and lactic acid. Furthermore, calculation of the Gibbs free energy strongly suggests that this reaction would proceed. In this paper, we describe for the first time microbial hydrogen production from acetic acid and lactic acid by fermentation.

  17. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    Halogenated fatty acids are the major contributors to organohalogen compounds in lipids of marine mammals, fish, and bivalves. For the initial characterization of these recently noticed compounds, a determination of the halogen concentration has usually been combined with some lipid isolation...... and separation method. This review covers separation by solid phase chromatography, gel permeation chromatography, and liquid-liquid extraction, followed by halogen determination. All studies performed according to this outline have indicated that the major organohalogen compounds are chlorinated fatty acids...... bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD...

  18. Calorimetry of Nucleic Acids.

    Science.gov (United States)

    Rozners, Eriks; Pilch, Daniel S; Egli, Martin

    2015-12-01

    This unit describes the application of calorimetry to characterize the thermodynamics of nucleic acids, specifically, the two major calorimetric methodologies that are currently employed: differential scanning (DSC) and isothermal titration calorimetry (ITC). DSC is used to study thermally induced order-disorder transitions in nucleic acids. A DSC instrument measures, as a function of temperature (T), the excess heat capacity (C(p)(ex)) of a nucleic acid solution relative to the same amount of buffer solution. From a single curve of C(p)(ex) versus T, one can derive the following information: the transition enthalpy (ΔH), entropy (ΔS), free energy (ΔG), and heat capacity (ΔCp); the state of the transition (two-state versus multistate); and the average size of the molecule that melts as a single thermodynamic entity (e.g., the duplex). ITC is used to study the hybridization of nucleic acid molecules at constant temperature. In an ITC experiment, small aliquots of a titrant nucleic acid solution (strand 1) are added to an analyte nucleic acid solution (strand 2), and the released heat is monitored. ITC yields the stoichiometry of the association reaction (n), the enthalpy of association (ΔH), the equilibrium association constant (K), and thus the free energy of association (ΔG). Once ΔH and ΔG are known, ΔS can also be derived. Repetition of the ITC experiment at a number of different temperatures yields the ΔCp for the association reaction from the temperature dependence of ΔH.

  19. Whither acid rain?

    Science.gov (United States)

    Brimblecombe, P

    2001-04-04

    Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  20. Ethylenediaminetetraacetic acid in endodontics.

    Science.gov (United States)

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-09-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented.

  1. Locked nucleic acid

    DEFF Research Database (Denmark)

    Jepsen, Jan Stenvang; Sørensen, Mads D; Wengel, Jesper

    2004-01-01

    Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic...... physiochemical properties of LNA and some of the difficulties that may be encountered when applying LNA technology. The central part of the review focuses on the use of LNA molecules in regulation of gene expression, including delivery to cells, stability, unspecific effects, toxicity, pharmacokinetics...

  2. Whither Acid Rain?

    Directory of Open Access Journals (Sweden)

    Peter Brimblecombe

    2000-01-01

    Full Text Available Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  3. Fatty acids of Thiobacillus thiooxidans.

    Science.gov (United States)

    Levin, R A

    1971-12-01

    Fatty acid spectra were made on Thiobacillus thiooxidans cultures both in the presence and absence of organic compounds. Small additions of glucose or acetate had no significant effect either on growth or fatty acid content. The addition of biotin had no stimulatory effect but did result in slight quantitative changes in the fatty acid spectrum. The predominant fatty acid was a C(19) cyclopropane acid.

  4. The Acid-Base Titration of a Very Weak Acid: Boric Acid

    Science.gov (United States)

    Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

    2012-01-01

    A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

  5. The Acid-Base Titration of a Very Weak Acid: Boric Acid

    Science.gov (United States)

    Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

    2012-01-01

    A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

  6. Catalytic acetoxylation of lactic acid to 2-acetoxypropionic acid, en route to acrylic acid

    NARCIS (Netherlands)

    Beerthuis, R.; Granollers, M.; Brown, D.R.; Salavagione, H.J.; Rothenberg, G.; Shiju, N.R.

    2015-01-01

    We present an alternative synthetic route to acrylic acid, starting from the platform chemical lactic acid and using heterogeneous catalysis. To improve selectivity, we designed an indirect dehydration reaction that proceeds via acetoxylation of lactic acid to 2-acetoxypropionic acid. This

  7. Lactic acid bacterial cell factories for gamma-aminobutyric acid.

    Science.gov (United States)

    Li, Haixing; Cao, Yusheng

    2010-11-01

    Gamma-aminobutyric acid is a non-protein amino acid that is widely present in organisms. Several important physiological functions of gamma-aminobutyric acid have been characterized, such as neurotransmission, induction of hypotension, diuretic effects, and tranquilizer effects. Many microorganisms can produce gamma-aminobutyric acid including bacteria, fungi and yeasts. Among them, gamma-aminobutyric acid-producing lactic acid bacteria have been a focus of research in recent years, because lactic acid bacteria possess special physiological activities and are generally regarded as safe. They have been extensively used in food industry. The production of lactic acid bacterial gamma-aminobutyric acid is safe and eco-friendly, and this provides the possibility of production of new naturally fermented health-oriented products enriched in gamma-aminobutyric acid. The gamma-aminobutyric acid-producing species of lactic acid bacteria and their isolation sources, the methods for screening of the strains and increasing their production, the enzymatic properties of glutamate decarboxylases and the relative fundamental research are reviewed in this article. And the potential applications of gamma-aminobutyric acid-producing lactic acid bacteria were also referred to.

  8. Aminolevulinic Acid Topical

    Science.gov (United States)

    ... on or under the skin that result from exposure to sunlight and can develop into skin cancer) of the ... acid will make your skin very sensitive to sunlight (likely to get sunburn). Avoid exposure of treated skin to direct sunlight or bright ...

  9. Multifunctional Cinnamic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Aikaterini Peperidou

    2017-07-01

    Full Text Available Our research to discover potential new multitarget agents led to the synthesis of 10 novel derivatives of cinnamic acids and propranolol, atenolol, 1-adamantanol, naphth-1-ol, and (benzylamino ethan-1-ol. The synthesized molecules were evaluated as trypsin, lipoxygenase and lipid peroxidation inhibitors and for their cytotoxicity. Compound 2b derived from phenoxyphenyl cinnamic acid and propranolol showed the highest lipoxygenase (LOX inhibition (IC50 = 6 μΜ and antiproteolytic activity (IC50 = 0.425 μΜ. The conjugate 1a of simple cinnamic acid with propranolol showed the higher antiproteolytic activity (IC50 = 0.315 μΜ and good LOX inhibitory activity (IC50 = 66 μΜ. Compounds 3a and 3b, derived from methoxylated caffeic acid present a promising combination of in vitro inhibitory and antioxidative activities. The S isomer of 2b also presented an interesting multitarget biological profile in vitro. Molecular docking studies point to the fact that the theoretical results for LOX-inhibitor binding are identical to those from preliminary in vitro study.

  10. Lactic acid and lactates

    NARCIS (Netherlands)

    Schreurs, V.V.A.M.

    2010-01-01

    This review aims to integrate the present state of knowledge on lactate metabolism in human and mammalian physiology as far as it could be subject to nutritional interventions. An integrated view on the nutritional, metabolic and physiological aspects of lactic acid and lactates might open a perspec

  11. Accidents with sulfuric acid

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  12. Uric acid and evolution

    National Research Council Canada - National Science Library

    Álvarez-Lario, Bonifacio; Macarrón-Vicente, Jesús

    2010-01-01

    Uric acid (UA) is the end product of purine metabolism in humans due to the loss of uricase activity by various mutations of its gene during the Miocene epoch, which led to humans having higher UA levels than other mammals. Furthermore, 90...

  13. Acid Rain Investigations.

    Science.gov (United States)

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  14. The Acid Rain Game.

    Science.gov (United States)

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  15. Acid Rain Classroom Projects.

    Science.gov (United States)

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  16. Hyaluronic Acid Assays

    DEFF Research Database (Denmark)

    Itenov, Theis S; Kirkby, Nikolai S; Bestle, Morten H

    2015-01-01

    BACKGROUD: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method. METHODS: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme...

  17. Koetjapic acid chloroform hemisolvate

    Directory of Open Access Journals (Sweden)

    Z. D. Nassar

    2010-06-01

    Full Text Available The asymmetric unit of the title compound, C30H46O4·0.5CHCl3, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS-7-(2-carboxyethyl-3,4b,7,10b,12a-pentamethyl-8-(prop-1-en-2-yl-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexadecahydrochrysene-3-carboxylic acid] molecule and one half-molecule of chloroform solvent, which is disordered about a twofold rotation axis. The symmetry-independent component is further disordered over two sites, with occupancies of 0.30 and 0.20. The koetjapic acid contains a fused four-ring system, A/B/C/D. The A/B, B/C and C/D junctions adopt E/trans/cis configurations, respectively. The conformation of ring A is intermediate between envelope and half-chair and ring B adopts an envelope conformation whereas rings C and D adopt chair conformations. A weak intramolecular C—H...O hydrogen bond is observed. The koetjapic acid molecules are linked into dimers by two pairs of intermolecular O—H...O hydrogen bonds. The dimers are stacked along the c axis.

  18. Phenylpyruvic acid in urine

    NARCIS (Netherlands)

    Meulemans, O.; Vergeer, E.G.

    1960-01-01

    The method of The, Fleury And Vink for the determination of phenylpyruvic acid (PPA) in urine is modified by measuring the extinction after the green colour with ferric chloride has faded, and subtracting this extinction from that found initially. More accurate values are obtained and low PPA values

  19. Acid Rain Classroom Projects.

    Science.gov (United States)

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  20. The Acid Rain Game.

    Science.gov (United States)

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  1. Acid Rain Investigations.

    Science.gov (United States)

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  2. Effect of domoic acid on brain amino acid levels.

    Science.gov (United States)

    Durán, R; Arufe, M C; Arias, B; Alfonso, M

    1995-03-01

    The administration of Domoic Acid (Dom) in a 0.2 mg/kg i.p. dose induces changes in the levels of amino acids of neurochemical interest (Asp, Glu, Gly, Tau, Ala, GABA) in different rat brain regions (hypothalamus, hippocampus, amygdala, striatum, cortex and midbrain). The most affected amino acid is the GABA, the main inhibitory amino acid neurotransmitter, whereas glutamate, the main excitatory amino acid, is not affected. The rat brain regions that seem to be the main target of the Dom action belong to the limbic system (hippocampus, amygdala). The possible implication of the amino acids in the actions of Dom is also discussed.

  3. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  4. Potentiometric determination of peroxodisulfuric acid during electrolysis sulfuric acid

    Directory of Open Access Journals (Sweden)

    Fedor Malchik

    2013-09-01

    Full Text Available Was proposed two potentiometric methods for determining peroxodisulfuric acid during electrolysis of sulfuric acid (potentiometric titration method and direct potentiometry, based on its interaction with a known excess of a solution Fe2+.

  5. Progress in engineering acid stress resistance of lactic acid bacteria.

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-02-01

    Lactic acid bacteria (LAB) are widely used for the production of a variety of fermented foods, and are considered as probiotic due to their health-promoting effect. However, LAB encounter various environmental stresses both in industrial fermentation and application, among which acid stress is one of the most important survival challenges. Improving the acid stress resistance may contribute to the application and function of probiotic action to the host. Recently, the advent of genomics, functional genomics and high-throughput technologies have allowed for the understanding of acid tolerance mechanisms at a systems level, and many method to improve acid tolerance have been developed. This review describes the current progress in engineering acid stress resistance of LAB. Special emphasis is placed on engineering cellular microenvironment (engineering amino acid metabolism, introduction of exogenous biosynthetic capacity, and overproduction of stress response proteins) and maintaining cell membrane functionality. Moreover, strategies to improve acid tolerance and the related physiological mechanisms are also discussed.

  6. Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from wine.

    Science.gov (United States)

    Campos, Francisco M; Figueiredo, Ana R; Hogg, Tim A; Couto, José A

    2009-06-01

    The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain.

  7. [Determination of scopolin, chlorogenic acid, scopoletin, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C in plants of Erycibe].

    Science.gov (United States)

    Xu, Xiao-kun; Chen, Zhi-yong; Liao, Li-ping; Zhang, Zi-jia; Wang, Zheng-tao

    2015-03-01

    An accurate and reliable analytical method for-simultaneous determination of six active components (scopolin, chlorogenic acid, scopoletin, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C) in plants of Erycibe was developed. Scopolin, chlorogenic acid, scopoletin, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C in the samples were well separated in analytical HPLC by gradual elution with methanol-0.1% formic acid solution. The chromatographic condictions: Agilent Poroshell 120 EC-C18 column, flowing rate being 1 mL x min(-1), detecting wavelength at 345 nm. Good linearities of scopolin, chlorogenic acid, scopoletin, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C were in the range of 0.026 8-2.68, 0.027 0-2.70, 0.008 1-0.81, 0.018 8-1.88, 0.017 6-1.76, 0.019 6-1.96 μg, respectively (r > 0.999 6). The average recoveries of the six components were 98.1%, 98.7%, 100.8%, 100.4%, 99.7%, 101.1%; the relative standard deviations were 2.67%, 2.86%, 2.62%, 1.98%, 2.76%, 2.19%. The method is simple, feasible and reproducible and can be used for the quality control of plants of Erycibe.

  8. Usnic acid controls the acidity tolerance of lichens.

    Science.gov (United States)

    Hauck, Markus; Jürgens, Sascha-René

    2008-11-01

    The hypotheses were tested that, firstly, lichens producing the dibenzofuran usnic acid colonize substrates characterized by specific pH ranges, secondly, this preferred pH is in a range where soluble usnic acid and its corresponding anion occur in similar concentrations, and thirdly, usnic acid makes lichens vulnerable to acidity. Lichens with usnic acid prefer an ambient pH range between 3.5 and 5.5 with an optimum between 4.0 and 4.5. This optimum is close to the pK(a1) value of usnic acid of 4.4. Below this optimum pH, dissolved SO(2) reduces the chlorophyll fluorescence yield more in lichens with than without their natural content of usnic acid. This suggests that usnic acid influences the acidity tolerance of lichens. The putative mechanism of the limited acidity tolerance of usnic acid-containing lichens is the acidification of the cytosol by molecules of protonated usnic acid shuttling protons through the plasma membrane at an apoplastic pH

  9. Circulating folic acid in plasma: relation to folic acid fortification

    Science.gov (United States)

    The implementation of folic acid fortification in the United States has resulted in unprecedented amounts of this synthetic form of folate in the American diet. Folic acid in circulation may be a useful measure of physiologic exposure to synthetic folic acid, and there is a potential for elevated co...

  10. Acetic acid extraction from aqueous solutions using fatty acids

    NARCIS (Netherlands)

    IJmker, H.M.; Gramblicka, M.; Kersten, Sascha R.A.; van der Ham, Aloysius G.J.; Schuur, Boelo

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  11. Acetic acid extraction from aqueous solutions using fatty acids

    NARCIS (Netherlands)

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  12. N-(3-Chlorophenylmaleamic acid

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-07-01

    Full Text Available In the title compound, C10H8ClNO3, the molecular conformation is stabilized by two intramolecular hydrogen bonds. The first is a short O—H...O hydrogen bond within the maleamic acid unit and the second is a C—H...O hydrogen bond which connects the amide group with the phenyl ring. The maleamic acid unit is essentially planar, with an r.m.s. deviation of 0.044 Å, and makes a dihedral angle of 15.2 (1° with the phenyl ring. In the crystal, intermolecular N—H...O hydrogen bonds link the molecules into C(7 chains running [010].

  13. Acid hydrolysis of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  14. Autohydrolysis of phytic acid.

    Science.gov (United States)

    Hull, S R; Gray, J S; Montgomery, R

    1999-09-10

    The autohydrolysis of phytic acid at 120 degrees C resulted in the formation of most of the phosphate esters of myo-inositol in varying amounts depending upon the reaction time. Eighteen of the 39 chromatographically distinct myo-inositol mono-, bis-, tris-, tetrakis-, pentakis-, and hexakisphosphates have been characterized using two different HPLC systems. These myo-inositol phosphates were partially purified by preparative anion-exchange chromatography under acidic and alkaline elution conditions. The combination of these two methods provides a two-tiered chromatographic approach to the rapid and sensitive identification of inositol phosphates in complex mixtures. Identification of the products was confirmed by 1D and 2D (1)H NMR analysis. The analytical procedure was applied to the autohydrolysis of the mixture of inositol phosphates from corn steep water.

  15. N-(3-Methylphenylsuccinamic acid

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-02-01

    Full Text Available In the crystal structure of the title compound, C11H13NO3, the conformations of the N—H and C=O bonds in the amide segment are anti to each other, and that of the amide H atom is anti to the meta-methyl group in the benzene ring. Furthermore, the conformations of the amide oxygen and the carbonyl O atom of the acid segment are also anti to the adjacent –CH2 groups. The C=O and O—H bonds of the acid group are syn to each other. In the crystal, the molecules are packed into infinite chains through intermolecular N—H...O and O—H...O hydrogen bonds.

  16. Accidents with sulfuric acid

    OpenAIRE

    Rajković Miloš B.

    2006-01-01

    Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eigh...

  17. Phenolic acids bioavailability

    OpenAIRE

    2011-01-01

    The daily intake of phenolic compounds does not necessarily reflect the dose at which they reach the physiological targets in the organisms. The biological activity of phenolic compounds metabolites found in blood, organs and target tissues, as a result of digestive and hepatic activity, may differ from those of the native forms of the substances. This review discusses the absorption and metabolism of phenolic acids, a class of phenolic compounds abundant in food, and the methodologies used f...

  18. Omega-3 fatty acids (image)

    Science.gov (United States)

    Omega-3 fatty acids are a form of polyunsaturated fat that the body derives from food. Omega-3s (and omega-6s) are known as essential fatty acids (EFAs) because they are important for good health. ...

  19. Folic Acid Questions and Answers

    Science.gov (United States)

    ... What effect does taking folic acid have on arsenic poisoning? In many countries in the world, arsenic in ... What effect does taking folic acid have on arsenic poisoning? In many countries in the world, arsenic in ...

  20. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2007-01-01

    Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness.......Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness....

  1. (boric acid) against Blattella germanica

    African Journals Online (AJOL)

    ufuoma

    2013-05-01

    May 1, 2013 ... study of the ovaries was done following the toxicity assays after having evaluated the toxicity of the boric acid ... Key words: German cockroach, boric acid, reproduction, ovary, biochemical. ... MATERIALS AND METHODS.

  2. Enzymic Synthesis of Caffeoylglucaric Acid from Chlorogenic Acid and Glucaric Acid by a Protein Preparation from Tomato Cotyledons 1

    Science.gov (United States)

    Strack, Dieter; Gross, Wiltrud; Wray, Victor; Grotjahn, Lutz

    1987-01-01

    The phenylpropane metabolism of tomato (Lycopersicon esculentum Mill) cotyledons was investigated. The HPLC analysis revealed two hydroxycinnamic-acid conjugates as major components, identified as chlorogenic acid (5-O-caffeoylquinic acid) and caffeoylglucaric acid (2-O- or 5-O-caffeoyl-glucaric acid). Quantitative analyses indicated a precursor-product relationship between the chlorogenic and caffeoylglucaric acids. Protein preparations from tomato cotyledons were found to catalyze the formation of caffeoylglucaric acid with chlorogenic acid as acyl donor and free glucaric acid as acceptor molecule. This enzyme activity, possibly to be classified as hydroxycinnamoylquinic acid:glucaric acid hydroxycinnamoyltransferase, acts together with hydroxycinnamoyl-CoA: quinic acid hydroxycinnamoyltransferase. PMID:16665274

  3. Biological properties of lipoic acid

    Directory of Open Access Journals (Sweden)

    Anna Bilska

    2002-06-01

    Full Text Available Lipoic acid is a prostetic group of H-protein of the glycine cleavage system and the dihydrolipoamide acyltransferases (E2 of the pyruvate, alpha-ketoglutarate and branched-chain alpha-keto acid dehydrogenase complexes. Lipoic acid and its reduced form, dihydrolipoic acid, reacts with oxygen reactive species. This paper reviews the beneficial effects in oxidative stress models or clinical conditions.

  4. Lewis Acid Catalyzed Benzylic Bromination

    OpenAIRE

    Shibatomi, Kazutaka; Zhang, Yanhua; Yamamoto, Hisashi

    2008-01-01

    Lewis acid catalyzed bromination on aromatic side chain was achieved efficiently by using 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) as a bromination reagent under mild conditions. Zirconium(IV) chloride showed the highest catalytic activity for the benzylic bromination. It was revealed that the present Lewis acid catalysis proceeds via the radical generation pathway. In contrast to Lewis acid catalysis, Brønsted acid promoted aromatic ring bromination without any benzylic bromination. Monobro...

  5. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  6. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  7. Fumaric acid production by fermentation

    NARCIS (Netherlands)

    Roa Engel, C.A.; Straathof, A.J.J.; Zijlmans, T.W.; Van Gulik, W.M.; Van der Wielen, L.A.M.

    2008-01-01

    Abstract The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid fr

  8. Pantothenic acid biosynthesis in zymomonas

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

    2014-07-01

    Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

  9. Acid Rain Limits Global Warming

    Institute of Scientific and Technical Information of China (English)

    Will Knight; 张林玲

    2004-01-01

    @@ Acid rain restricts global warming by reducing methane① emissions from natural wetland areas, suggests a global climate study. Acid rain is the result of industrial pollution,which causes rainwater to carry small quantities of acidic compoumds② such as sulphuric and nitric acid③. Contaminated rainwater can upset rivers and lakes, killing fish and other organisms and also damage plants, trees and buildings.

  10. Microbial degradation of poly(amino acid)s.

    Science.gov (United States)

    Obst, Martin; Steinbüchel, Alexander

    2004-01-01

    Natural poly(amino acid)s are a group of poly(ionic) molecules (ionomers) with various biological functions and putative technical applications and play, therefore, an important role both in nature and in human life. Because of their biocompatibility and their synthesis from renewable resources, poly(amino acid)s may be employed for many different purposes covering a broad spectrum of medical, pharmaceutical, and personal care applications as well as the domains of agriculture and of environmental applications. Biodegradability is one important advantage of naturally occurring poly(amino acid)s over many synthetic polymers. The intention of this review is to give an overview about the enzyme systems catalyzing the initial steps in poly(amino acid) degradation. The focus is on the naturally occurring poly(amino acid)s cyanophycin, poly(epsilon-L-lysine) and poly(gamma-glutamic acid); but biodegradation of structurally related synthetic polyamides such as poly(aspartic acid) and nylons, which are known from various technical applications, is also included.

  11. Molecular Interaction of Pinic Acid with Sulfuric Acid

    DEFF Research Database (Denmark)

    Elm, Jonas; Kurten, Theo; Bilde, Merete

    2014-01-01

    We investigate the molecular interactions between the semivolatile α-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated...... from the corresponding ΔG values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ΔG values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid...... cluster. The involvement of more than one pinic acid molecule in a single cluster is observed to lead to the formation of favorable (pinic acid)2(H2SO4) and (pinic acid)2(H2SO4)2 clusters. The identified most favorable growth paths starting from a single pinic acid molecule lead to closed structures...

  12. Heterogeneous uptake of amines by citric acid and humic acid.

    Science.gov (United States)

    Liu, Yongchun; Ma, Qingxin; He, Hong

    2012-10-16

    Heterogeneous uptake of methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) onto citric acid and humic acid was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer at 298 K. Acid-base reactions between amines and carboxylic acids were confirmed. The observed uptake coefficients of MA, DMA, and TMA on citric acid at 298 K were measured to be 7.31 ± 1.13 × 10(-3), 6.65 ± 0.49 × 10(-3), and 5.82 ± 0.68 × 10(-3), respectively, and showed independence of sample mass. The observed uptake coefficients of MA, DMA, and TMA on humic acid at 298 K increased linearly with sample mass, and the true uptake coefficients of MA, DMA, and TMA were measured to be 1.26 ± 0.07 × 10(-5), 7.33 ± 0.40 × 10(-6), and 4.75 ± 0.15 × 10(-6), respectively. Citric acid, having stronger acidity, showed a higher reactivity than humic acid for a given amine; while the steric effect of amines was found to govern the reactivity between amines and citric acid or humic acid.

  13. Microbial transformations of isocupressic acid.

    Science.gov (United States)

    Lin, S J; Rosazza, J P

    1998-07-01

    Microbial transformations of the labdane-diterpene isocupressic acid (1) with different microorganisms yielded several oxygenated metabolites that were isolated and characterized by MS and NMR spectroscopic analyses. Nocardia aurantia (ATCC 12674) catalyzed the cleavage of the 13,14-double bond to yield a new nor-labdane metabolite, 2. Cunninghamella elegans (-) (NRRL 1393) gave 7beta-hydroxyisocupressic acid (3) and labda-7,13(E)-diene-6beta,15, 17-triol-19-oic acid (4), and Mucor mucedo (ATCC 20094) gave 2alpha-hydroxyisocupressic acid (5) and labda-8(17),14-diene-2alpha, 13-diol-19-oic acid (6).

  14. Amino Acid Catabolism in Plants.

    Science.gov (United States)

    Hildebrandt, Tatjana M; Nunes Nesi, Adriano; Araújo, Wagner L; Braun, Hans-Peter

    2015-11-02

    Amino acids have various prominent functions in plants. Besides their usage during protein biosynthesis, they also represent building blocks for several other biosynthesis pathways and play pivotal roles during signaling processes as well as in plant stress response. In general, pool sizes of the 20 amino acids differ strongly and change dynamically depending on the developmental and physiological state of the plant cell. Besides amino acid biosynthesis, which has already been investigated in great detail, the catabolism of amino acids is of central importance for adjusting their pool sizes but so far has drawn much less attention. The degradation of amino acids can also contribute substantially to the energy state of plant cells under certain physiological conditions, e.g. carbon starvation. In this review, we discuss the biological role of amino acid catabolism and summarize current knowledge on amino acid degradation pathways and their regulation in the context of plant cell physiology.

  15. Acidic aerosol in urban air

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, M.; Yamaoka, S.; Miyazaki, T.; Oka, M.

    1982-01-01

    The distribution and chemical composition of acidic aerosol in Osaka City were investigated. Samples were collected at five sites in the city from June to September, 1979. Acidic aerosol was determined by the acid-base titration method, sulfate ion by barium chloride turbidimetry, nitrate ion by the xylenol method, and chloride ion by the mercury thiocyanate method. The concentration of acidic aerosol at five sites ranged from 7.7 micrograms per cubic meter to 10.0 micrograms per cubic meter, but mean concentrations in the residential area were slightly higher than those in the industrial area. When acidic aerosol concentrations were compared with concentrations of sulfate, nitrate, and chloride ions, a significant correlation was found between acidic aerosol and sulfate ion. The sum of the ion equivalents of the three types showed good correlation with the acidic aerosol equivalent during the whole period.

  16. Nucleic Acid Vaccines

    Institute of Scientific and Technical Information of China (English)

    LU Shan

    2004-01-01

    @@ Anew method of immunization was discovered in the early 1990s. Several research groups independently demonstrated that direct inoculation of DNA plasmids coding for a specific protein antigen could elicit immune responses against that antigen[1-4].Since in theory the mRNA molecules also have the potential to be translated into the protein antigen, this vaccination approach was officially named by WHO as the nucleic acid vaccination even though the term DNA vaccine has been used more commonly in the literature. This novel approach is considered the fourth generation of vaccines after live attenuated vaccines, killed or inactivated vaccines and recombinant protein based subunit vaccines.

  17. Mycophenolic Acid in Silage

    Science.gov (United States)

    Schneweis, Isabell; Meyer, Karsten; Hörmansdorfer, Stefan; Bauer, Johann

    2000-01-01

    We examined 233 silage samples and found that molds were present in 206 samples with counts between 1 × 103 and 8.9 × 107 (mean, 4.7 × 106) CFU/g. Mycophenolic acid, a metabolite of Penicillium roqueforti, was detected by liquid chromatography-mass spectrometry in 74 (32%) of these samples at levels ranging from 20 to 35,000 (mean, 1,400) μg/kg. This compound has well-known immunosuppressive properties, so feeding with contaminated silage may promote the development of infectious diseases in livestock. PMID:10919834

  18. New Acid Combination for a Successful Sandstone Acidizing

    Science.gov (United States)

    Shafiq, M. U.; Mahmud, H. K. B.; Rezaee, R.

    2017-05-01

    With the development of new enhanced oil recovery techniques, sandstone acidizing has been introduced and played a pivotal role in the petroleum industry. Different acid combinations have been applied, which react with the formation, dissolve the soluble particles; thus increase the production of hydrocarbons. To solve the problems which occurred using current preflush sandstone acidizing technology (hydrochloric acid); a new acid combination has been developed. Core flooding experiments on sandstone core samples with dimensions 1.5 in. × 3 in. were conducted at a flow rate of 2 cm3/min. A series of hydrochloric-acetic acid mixtures with different ratios were tested under 150°F temperature. The core flooding experiments performed are aimed to dissolve carbonate, sodium, potassium and calcium particles from the core samples. These experiments are followed by few important tests which include, porosity-permeability, pH value, Inductively Coupled Plasma (ICP) analysis and Nuclear Magnetic Resonance (NMR measurements). All the results are compared with the results of conventional hydrochloric acid technology. NMR and porosity analysis concluded that the new acid combination is more effective in creating fresh pore spaces and thus increasing the reservoir permeability. It can be seen from the pore distribution before and after the acidizing. Prior applying acid; the large size of pores appears most frequently in the pore distribution while with the applied acid, it was found that the small pore size is most the predominant of the pore distribution. These results are validated using ICP analysis which shows the effective removal of calcium and other positive ions from the core sample. This study concludes that the combination of acetic-hydrochloric acid can be a potential candidate for the preflush stage of sandstone acidizing at high temperature reservoirs.

  19. Bicyclic glutamic acid derivatives.

    Science.gov (United States)

    Meyer, Udo; Bisel, Philippe; Weckert, Edgar; Frahm, August Wilhelm

    2006-05-15

    For the second-generation asymmetric synthesis of the trans-tris(homoglutamic) acids via Strecker reaction of chiral ketimines, the cyanide addition as the key stereodifferentiating step produces mixtures of diastereomeric alpha-amino nitrile esters the composition of which is independent of the reaction temperature and the type of the solvent, respectively. The subsequent hydrolysis is exclusively achieved with concentrated H(2)SO(4) yielding diastereomeric mixtures of three secondary alpha-amino alpha-carbamoyl-gamma-esters and two diastereomeric cis-fused angular alpha-carbamoyl gamma-lactams as bicyclic glutamic acid derivatives, gained from in situ stereomer differentiating cyclisation of the secondary cis-alpha-amino alpha-carbamoyl-gamma-esters. Separation was achieved by CC. The pure secondary trans-alpha-amino alpha-carbamoyl-gamma-esters cyclise on heating and treatment with concentrated H(2)SO(4), respectively, to diastereomeric cis-fused angular secondary alpha-amino imides. Their hydrogenolysis led to the enantiomeric cis-fused angular primary alpha-amino imides. The configuration of all compounds was completely established by NMR methods, CD-spectra, and by X-ray analyses of the (alphaR,1R,5R)-1-carbamoyl-2-(1-phenylethyl)-2-azabicyclo[3.3.0]octan-3-one and of the trans-alphaS,1S,2R-2-ethoxycarbonylmethyl-1-(1-phenylethylamino)cyclopentanecarboxamide.

  20. Cryoprotection from lipoteichoic acid

    Science.gov (United States)

    Rice, Charles V.; Middaugh, Amy; Wickham, Jason R.; Friedline, Anthony; Thomas, Kieth J.; Johnson, Karen; Zachariah, Malcolm; Garimella, Ravindranth

    2012-10-01

    Numerous chemical additives lower the freezing point of water, but life at sub-zero temperatures is sustained by a limited number of biological cryoprotectants. Antifreeze proteins in fish, plants, and insects provide protection to a few degrees below freezing. Microbes have been found to survive at even lower temperatures, and with a few exceptions, antifreeze proteins are missing. Survival has been attributed to external factors, such as the high salt concentration of brine veins and adhesion to particulates or ice crystal defects. We have discovered an endogenous cryoprotectant in the cell wall of bacteria, lipoteichoic acid biopolymers. Adding 1% LTA to bacteria cultures immediately prior to freezing provides 50% survival rate, similar to the results obtained with 1% glycerol. In the absence of an additive, bacterial survival is negligible as measured with the resazurin cell viability assay. The mode of action for LTA cryoprotection is unknown. With a molecular weight of 3-5 kDa, it is unlikely to enter the cell cytoplasm. Our observations suggest that teichoic acids could provide a shell of liquid water around biofilms and planktonic bacteria, removing the need for brine veins to prevent bacterial freezing.

  1. Acid Ceramidase in Melanoma

    DEFF Research Database (Denmark)

    Realini, Natalia; Palese, Francesca; Pizzirani, Daniela

    2016-01-01

    Acid ceramidase (AC) is a lysosomal cysteine amidase that controls sphingolipid signaling by lowering the levels of ceramides and concomitantly increasing those of sphingosine and its bioactive metabolite, sphingosine 1-phosphate. In the present study, we evaluated the role of AC-regulated sphing......Acid ceramidase (AC) is a lysosomal cysteine amidase that controls sphingolipid signaling by lowering the levels of ceramides and concomitantly increasing those of sphingosine and its bioactive metabolite, sphingosine 1-phosphate. In the present study, we evaluated the role of AC......-regulated sphingolipid signaling in melanoma. We found that AC expression is markedly elevated in normal human melanocytes and proliferative melanoma cell lines, compared with other skin cells (keratinocytes and fibroblasts) and non-melanoma cancer cells. High AC expression was also observed in biopsies from human...... generate lower amounts of ceramides than normal melanocytes do. This down-regulation in ceramide production appears to result from suppression of the de novo biosynthesis pathway. To test whether AC might contribute to melanoma cell proliferation, we blocked AC activity using a new potent (IC50 = 12 n...

  2. Kinetics of wet oxidation of formic acid and acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Mahajani, V.V. [Univ. of Mumbai (India). Dept. of Chemical Technology

    1997-11-01

    Oxidation of lower molecular weight carboxylic acids such as formic, acetic, glyoxalic, and oxalic acids is often the rate-controlling step during wet oxidation (WO) of an aqueous waste stream exhibiting very high chemical oxygen demand (COD). The kinetics of WO of formic acid was studied in the absence and presence of a cupric sulfate as catalyst in the temperature range 150--240 C and oxygen partial pressure range 0.345--1.380 MPa. Wet oxidation of acetic acid was carried out in the presence of cupric sulfate in the temperature range 215--235 C. Homogeneous copper sulfate was found to be a very good catalyst for oxidation of formic acid and acetic acid.

  3. Solid acid catalysis from fundamentals to applications

    CERN Document Server

    Hattori, Hideshi

    2014-01-01

    IntroductionTypes of solid acid catalystsAdvantages of solid acid catalysts Historical overviews of solid acid catalystsFuture outlookSolid Acids CatalysisDefinition of acid and base -Brnsted acid and Lewis acid-Acid sites on surfacesAcid strengthRole of acid sites in catalysisBifunctional catalysisPore size effect on catalysis -shape selectivity-Characterization of Solid Acid Catalysts Indicator methodTemperature programmed desorption (TPD) of ammoniaCalorimetry of adsorption of basic moleculesInfrare

  4. Japodic Acid, A Novel Aliphatic Acid from Jatropha podagrica Hook

    OpenAIRE

    Aiyelaagbe, Olapeju O.; Gloer, James B.

    2008-01-01

    A new aliphatic acid named japodic acid (1) with a gem-dimethyl cyclopropane ring has been isolated from the roots of Jatropha podagrica. Its structure was established by 1D and 2D NMR and mass spectrometric data. Two other known compounds, erythrinasinate (2) and fraxidin (3) were also isolated from this plant for the first time. Japodic acid showed mild insect growth inhibition activity against Helicoverpa zea (37% growth reduction at 100 ppm). Fraxidin and erythrinasinate exhibited antibac...

  5. Electrolytic nature of aqueous sulfuric acid. 2. Acidity.

    Science.gov (United States)

    Fraenkel, Dan

    2012-09-27

    In part 1 of this study, I reported that the Debye-Hückel limiting law and the smaller-ion shell (SiS) model of strong electrolyte solutions fit nicely with the experimental mean ionic activity coefficient (γ(±)) of aqueous sulfuric acid as a function of concentration and of temperature when the acid is assumed to be a strong 1-3 electrolyte. Here, I report that the SiS-derived activity coefficient of H(+), γ(H(+)), of the 1-3 acid is comparable to that of aqueous HCl. This agrees with titration curves showing, as well-known, that sulfuric acid in water is parallel in strength to aqueous HCl. The calculated pH is in good accord with the Hammett acidity function, H(0), of aqueous sulfuric acid at low concentration, and differences between the two functions at high concentration are discussed and explained. This pH-H(0) relation is consistent with the literature showing that the H(0) of sulfuric acid (in the 1-9 M range) is similar to those of HCl and the other strong mineral monoprotic acids. The titration of aqueous sulfuric acid with NaOH does not agree with the known second dissociation constant of 0.010 23; rather, the constant is found to be ~0.32 and the acid behaves upon neutralization as a strong diprotic acid practically dissociating in one step. A plausible reaction pathway is offered to explain how the acid may transform, upon base neutralization, from a dissociated H(4)SO(5) (as 3H(+) and HSO(5)(3-)) to a dissociated H(2)SO(4) even though the equilibrium constant of the reaction H(+) + HSO(5)(3-) ↔ SO(4)(2-) + H(2)O, at 25 °C, is 10(-37) (part 1).

  6. Bile acid interactions with cholangiocytes

    Institute of Scientific and Technical Information of China (English)

    Xuefeng Xia; Heather Francis; Shannon Glaser; Gianfranco Alpini; Gene LeSage

    2006-01-01

    Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane. A selective transporter for bile acids, the Apical Sodium Bile Acid Cotransporter (ASBT) (also referred to as Ibat; gene name Slc10a2)is localized on the cholangiocyte apical membrane. On the basolateral membrane, four transport systems have been identified (t-ASBT, multidrug resistance (MDR)3,an unidentified anion exchanger system and organic solute transporter (Ost) heteromeric transporter, OstαOstβ. Together, these transporters unidirectionally move bile acids from ductal bile to the circulation. Bile acids absorbed by cholangiocytes recycle via the peribiliaryplexus back to hepatocytes for re-secretion into bile.This recycling of bile acids between hepatocytes and cholangiocytes is referred to as the cholehepatic shunt pathway. Recent studies suggest that the cholehepatic shunt pathway may contribute in overall hepatobiliary transport of bile acids and to the adaptation to chronic cholestasis due to extrahepatic obstruction. ASBT is acutely regulated by an adenosine 3', 5'-monophosphate (cAMP)-dependent translocation to the apical membrane and by phosphorylation-dependent ubiquitination and proteasome degradation. ASBT is chronically regulated by changes in gene expression in response to biliary bile acid concentration and inflammatory cytokines.Another potential function of cholangiocyte ASBT is to allow cholangiocytes to sample biliary bile acids in order to activate intracellular signaling pathways. Bile acids trigger changes in intracellular calcium, protein kinase C (PKC), phosphoinositide 3-kinase (PI3K), mitogenactivated protein (MAP) kinase and extracellular signalregulated protein kinase (ERK) intracellular signals.Bile acids significantly alter cholangiocyte secretion,proliferation and survival. Different bile acids have differential effects on cholangiocyte intracellular signals,and in some instances trigger opposing effects on cholangiocyte secretion

  7. Citric acid production patent review.

    Science.gov (United States)

    Anastassiadis, Savas; Morgunov, Igor G; Kamzolova, Svetlana V; Finogenova, Tatiana V

    2008-01-01

    Current Review article summarizes the developments in citric acid production technologies in East and West last 100 years. Citric acid is commercially produced by large scale fermentation mostly using selected fungal or yeast strains in aerobe bioreactors and still remains one of the runners in industrial production of biotechnological bulk metabolites obtained by microbial fermentation since about 100 years, reflecting the historical development of modern biotechnology and fermentation process technology in East and West. Citric acid fermentation was first found as a fungal product in cultures of Penicillium glaucum on sugar medium by Wehmer in 1893. Citric acid is an important multifunctional organic acid with a broad range of versatile uses in household and industrial applications that has been produced industrially since the beginning of 20(th) century. There is a great worldwide demand for citric acid consumption due to its low toxicity, mainly being used as acidulant in pharmaceutical and food industries. Global citric acid production has reached 1.4 million tones, increasing annually at 3.5-4.0% in demand and consumption. Citric acid production by fungal submerged fermentation is still dominating, however new perspectives like solid-state processes or continuous yeast processes can be attractive for producers to stand in today's strong competition in industry. Further perspectives aiming in the improvement of citric acid production are the improvement of citric acid producing strains by classical and modern mutagenesis and selection as well as downstream processes. Many inexpensive by-products and residues of the agro-industry (e.g. molasses, glycerin etc.) can be economically utilized as substrates in the production of citric acid, especially in solid-state fermentation, enormously reducing production costs and minimizing environmental problems. Alternatively, continuous processes utilizing yeasts which reach 200-250 g/l citric acid can stand in today

  8. Role of Ribonucleic Acid Synthesis in Replication of Deoxyribonucleic Acid

    Science.gov (United States)

    Pato, Martin L.

    1975-01-01

    An experiment previously interpreted to show a ribonucleic acid requirement for propagation of deoxyribonucleic replication is reexamined and the earlier interpretation is shown to be incorrect. PMID:1090599

  9. Rotational study of the bimolecule acetic acid-fluoroacetic acid

    Science.gov (United States)

    Feng, Gang; Gou, Qian; Evangelisti, Luca; Caminati, Walther

    2017-01-01

    The rotational spectrum of the acetic acid-fluoroacetic acid bimolecule was measured by using a pulsed jet Fourier transform microwave spectrometer. One conformer, in which fluoroacetic acid is in trans form, has been observed. The rotational transitions are split into two component lines, due to the internal rotation of the methyl group of acetic acid. From these splittings, the corresponding V3 barrier has been determined. The dissociation energy of this complex has been estimated to 66 kJ/mol. An increase of the distance between the two monomers upon the OH → OD substitution (Ubbelohde effect) has been observed.

  10. Evaluation of ascorbic acid in protecting labile folic acid derivatives.

    OpenAIRE

    1983-01-01

    The use of ascorbic acid as a reducing agent to protect labile, reduced derivatives of folic acid has been evaluated by high-performance liquid chromatographic separations and Lactobacillus casei microbiological assay of eluate fractions. Upon heating for 10 min at 100 degrees C, solutions of tetrahydropteroylglutamic acid (H4PteGlu) in 2% sodium ascorbate gave rise to 5,10-methylene-H4PteGlu and 5-methyl-H4PteGlu. H2PteGlu acid gave rise to 5-methyl-H4PteGlu and PteGlu. 10-Formyl-H4PteGlu ga...

  11. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    OpenAIRE

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M B

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn hydrolysis to salicylic acid. With the method for free acetylsalicylic acid and salicylic acid, recovery was 95-98␏or acetylsalicylic acid added to foods and 92-102␏or salicylic acid. Recovery of a...

  12. Esterification by the Plasma Acidic Water: Novel Application of Plasma Acid

    Science.gov (United States)

    Gu, Ling

    2014-03-01

    This work explores the possibility of plasma acid as acid catalyst in organic reactions. Plasma acidic water was prepared by dielectric barrier discharge and used to catalyze esterification of n-heptanioc acid with ethanol. It is found that the plasma acidic water has a stable and better performance than sulfuric acid, meaning that it is an excellent acid catalyst. The plasma acidic water would be a promising alternative for classic mineral acid as a more environment friendly acid.

  13. 49 CFR 173.158 - Nitric acid.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric acid. 173.158 Section 173.158... Nitric acid. (a) Nitric acid exceeding 40 percent concentration may not be packaged with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as...

  14. Molecular Simulation of Naphthenic Acid Removal on Acidic Catalyst Ⅱ. Experimental results of catalytic decarboxylation over acidic catalysts

    Institute of Scientific and Technical Information of China (English)

    Fu Xiaoqin; Tian Songbai; Hou Shuandi; Longjun; Wang Xieqing

    2008-01-01

    The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Br(o)nsted acid and Lewis acid were analyzed using molecular simulation technology.Compared with thermal decarboxylation reactions of petroleum acids, the decarboxylation reactions by acid catalysts were easier to occur. The decarboxylaton effect by Lewis acid was better than Br(o)nsted acid. The mechanisms of catalytic decarboxylation over acid catalyst were also verified by experiments on a fixed bed and a fluidized bed, the experimental results showed that the rate of acid removal could reach up to 97% over the acidic catalyst at a temperature above 400℃.

  15. Nanoclusters of Cyanuric Acid

    Indian Academy of Sciences (India)

    M ELANGO; V SUBRAMANIAN; N SATHYAMURTHY

    2017-07-01

    In this article, the self-assembly of cyanuric acid (CA) molecules into nano-structures is examined. Equilibrium geometry of CA is planar and it belongs to the D3h point group. It is shown that CA clusters form three dimensional bowls and balls. Cyclic pentamer (5-bowl) is the basic motif responsible for these non-planar geometries. It is also shown that the cyclic hexamer based clusters can be non-planar if they contain a 5-bowl. A unified criterion for the formation of bowls and balls from basic molecular building blocks emerges from this study. The role of symmetry in supramolecular self-assembly is also clearly evident from the present study.

  16. Acid mine drainage

    Science.gov (United States)

    Bigham, Jerry M.; Cravotta, Charles A.

    2016-01-01

    Acid mine drainage (AMD) consists of metal-laden solutions produced by the oxidative dissolution of iron sulfide minerals exposed to air, moisture, and acidophilic microbes during the mining of coal and metal deposits. The pH of AMD is usually in the range of 2–6, but mine-impacted waters at circumneutral pH (5–8) are also common. Mine drainage usually contains elevated concentrations of sulfate, iron, aluminum, and other potentially toxic metals leached from rock that hydrolyze and coprecipitate to form rust-colored encrustations or sediments. When AMD is discharged into surface waters or groundwaters, degradation of water quality, injury to aquatic life, and corrosion or encrustation of engineered structures can occur for substantial distances. Prevention and remediation strategies should consider the biogeochemical complexity of the system, the longevity of AMD pollution, the predictive power of geochemical modeling, and the full range of available field technologies for problem mitigation.

  17. Enzymatic tRNA acylation by acid and alpha-hydroxy acid analogues of amino acids.

    Science.gov (United States)

    Owczarek, Alina; Safro, Mark; Wolfson, Alexey D

    2008-01-08

    Incorporation of unnatural amino acids with unique chemical functionalities has proven to be a valuable tool for expansion of the functional repertoire and properties of proteins as well as for structure-function analysis. Incorporation of alpha-hydroxy acids (primary amino group is substituted with hydroxyl) leads to the synthesis of proteins with peptide bonds being substituted by ester bonds. Practical application of this modification is limited by the necessity to prepare corresponding acylated tRNA by chemical synthesis. We investigated the possibility of enzymatic incorporation of alpha-hydroxy acid and acid analogues (lacking amino group) of amino acids into tRNA using aminoacyl-tRNA synthetases (aaRSs). We studied direct acylation of tRNAs by alpha-hydroxy acid and acid analogues of amino acids and corresponding chemically synthesized analogues of aminoacyl-adenylates. Using adenylate analogues we were able to enzymatically acylate tRNA with amino acid analogues which were otherwise completely inactive in direct aminoacylation reaction, thus bypassing the natural mechanisms ensuring the selectivity of tRNA aminoacylation. Our results are the first demonstration that the use of synthetic aminoacyl-adenylates as substrates in tRNA aminoacylation reaction may provide a way for incorporation of unnatural amino acids into tRNA, and consequently into proteins.

  18. Ghrelin and gastric acid secretion.

    Science.gov (United States)

    Yakabi, Koji; Kawashima, Junichi; Kato, Shingo

    2008-11-07

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-induced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

  19. Racemization of Meteoritic Amino Acids

    Science.gov (United States)

    Cohen, Barbara A.; Chyba, Christopher F.

    2000-05-01

    Meteorites may have contributed amino acids to the prebiotic Earth, affecting the global ratio of right-handed to left-handed (D/L) molecules. We calculate D/L ratios for seven biological, α-hydrogen, protein amino acids over a variety of plausible parent body thermal histories, based on meteorite evidence and asteroid modeling. We show that amino acids in meteorites do not necessarily undergo complete racemization by the time they are recovered on Earth. If the mechanism of amino acid formation imposes some enantiomeric preference on the amino acids, a chiral signature can be retained through the entire history of the meteorite. Original enantiomeric excesses in meteorites such as Murchison, which have undergone apparently short and cool alteration scenarios, should have persisted to the present time. Of the seven amino acids for which relevant data are available, we expect glutamic acid, isoleucine, and valine, respectively, to be the most likely to retain an initial enantiomeric excess, and phenylalanine, aspartic acid, and alanine the least. Were the D/L ratio initially identical in each amino acid, final D/L ratios could be used to constrain the initial ratio and the thermal history experienced by the whole suite.

  20. Antibiofilm Properties of Acetic Acid

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup;

    2014-01-01

    of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram......-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms....

  1. Preparation and characterization Al3+-bentonite Turen Malang for esterification fatty acid (palmitic acid, oleic acid and linoleic acid)

    Science.gov (United States)

    Abdulloh, Abdulloh; Aminah, Nanik Siti; Triyono, Mudasir, Trisunaryanti, Wega

    2016-03-01

    Catalyst preparation and characterization of Al3+-bentonite for esterification of palmitic acid, oleic acid and linoleic acid has been done. Al3+-bentonite catalyst was prepared from natural bentonite of Turen Malang through cation exchange reaction using AlCl3 solution. The catalysts obtained were characterized by XRD, XRF, pyridine-FTIR and surface area analyser using the BET method. Catalyst activity test of Al3+-bentonite for esterification reaction was done at 65°C using molar ratio of metanol-fatty acid of 30:1 and 0.25 g of Al3+-bentonite catalyst for the period of ½, 1, 2, 3, 4 and 5 hours. Based on the characterization results, the Al3+-bentonite Turen Malang catalyst has a d-spacing of 15.63 Ǻ, acid sites of Brönsted and Lewis respectively of 230.79 µmol/g and 99.39 µmol/g, surface area of 507.3 m2/g and the average of radius pore of 20.09 Å. GC-MS analysis results of the oil phase after esterification reaction showed the formation of biodiesel (FAME: Fatty acid methyl ester), namely methyl palmitate, methyl oleate and methyl linoleate. The number of conversions resulted in esterification reaction using Al3+-bentonite Turen Malang catalyst was 74.61%, 37.75%, and 20, 93% for the esterification of palmitic acid, oleic acid and linoleic acid respectively.

  2. [Hydrofluoric acid poisoning: case report].

    Science.gov (United States)

    Cortina, Tatiana Judith; Ferrero, Hilario Andrés

    2013-01-01

    Hydrofluoric acid is a highly dangerous substance with industrial and domestically appliances. Clinical manifestations of poisoning depend on exposure mechanism, acid concentration and exposed tissue penetrability. Gastrointestinal tract symptoms do not correlate with injury severity. Patients with history of hydrofluoric acid ingestion should undergo an endoscopy of the upper gastrointestinal tract. Intoxication requires immediate intervention because systemic toxicity can take place. We present a 5 year old girl who accidentally swallowed 5 ml of 20% hydrofluoric acid. We performed gastrointestinal tract endoscopy post ingestion, which revealed erythematous esophagus and stomach with erosive lesions. Two months later, same study was performed and revealed esophagus and stomach normal mucous membrane.

  3. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  4. Retinoic acid and iron metabolism

    DEFF Research Database (Denmark)

    Chakraborty, Surajit; Bhattacharyya, Rajasri; Sayal, Kirtimaan

    2014-01-01

    tuberculosis controlling molecules in the days to come. Iron has proven to be essential for pathogenesis of tuberculosis and retinoic acid is known to influence the iron metabolism pathway. Retenoic acid is also known to exhibit antitubercular effect in in vivo system. Therefore there is every possibility...... that retinoic acid by affecting the iron metabolism pathway exhibits its antimycobacterial effect. These aspects are reviewed in the present manuscript for understanding the antimycobacterial role of retinoic acid in the context of iron metabolism and other immunological aspects....

  5. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  6. Biotechnological production of citric acid

    National Research Council Canada - National Science Library

    Max, Belén; Salgado, José Manuel; Rodríguez, Noelia; Cortés, Sandra; Converti, Attilio; Domínguez, José Manuel

    2010-01-01

    This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors...

  7. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances.

    Science.gov (United States)

    Lee, Je Min; Lee, Hyungjae; Kang, SeokBeom; Park, Woo Jung

    2016-01-04

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism.

  8. Peptide Nucleic Acids Having Amino Acid Side Chains

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting...

  9. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    Directory of Open Access Journals (Sweden)

    Je Min Lee

    2016-01-01

    Full Text Available Polyunsaturated fatty acids (PUFAs are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism.

  10. Carbonic Acid Pretreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

    2003-05-31

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic

  11. Carbonic Acid Retreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Baylor university

    2003-06-01

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for

  12. Ghrelin and gastric acid secretion

    Institute of Scientific and Technical Information of China (English)

    Koji Yakabi; Junichi Kawashima; Shingo Kato

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric add secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

  13. Amino acids in Arctic aerosols

    Directory of Open Access Journals (Sweden)

    E. Scalabrin

    2012-11-01

    Full Text Available Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS to analyze 20 amino acids and quantify compounds at fmol m−3 levels. Mean total FAA concentration was 1070 fmol m−3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45–60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m−3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (< 0.49 μm and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanic emissions.

  14. Amino acids in Arctic aerosols

    Directory of Open Access Journals (Sweden)

    E. Scalabrin

    2012-07-01

    Full Text Available Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS to analyze 20 amino acids to quantify compounds at fmol m−3 levels. Mean total FAA concentration was 1070 fmol m−3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45–60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m−3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (<0.49 μm and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanics.

  15. The acidic amino acids of tulip: isolation of γ-ethylideneglutamic acid

    Science.gov (United States)

    Fowden, L.

    1966-01-01

    1. γ-Ethylideneglutamic acid has been isolated from fruit capsules of tulip plants. 2. The assigned structure was indicated by examining the products formed after oxidation and catalytic hydrogenation and was confirmed by nuclear-magnetic-resonance spectroscopy and by synthesis of γ-ethylglutamic acid. 3. The ability of γ-ethylideneglutamic acid to participate in transamination and decarboxylation reactions was examined. PMID:5938664

  16. Infrared spectra of hydrogen-bonded salicylic acid and its derivatives : Salicylic acid and acetylsalicylic acid

    Science.gov (United States)

    Wójcik, Marek J.

    1981-11-01

    Infrared spectra of hydrogen-bonded salicylic acid, O-deutero-salicylic acid and acetylsalicylic acid crystals have been studied experimentally and theoretically. Interpretation of these spectra was based on the Witkowski-Maréchal model. Semi-quantitative agreement between experimental and theoretical spectra can be achieved with the simplest form of this model, with values of interaction parameters transferable for equivalent intermolecular hydrogen bonds.

  17. Production of succinic Acid from citric Acid and related acids by lactobacillus strains.

    Science.gov (United States)

    Kaneuchi, C; Seki, M; Komagata, K

    1988-12-01

    A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, alpha-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli.

  18. A mononucleotide repeat in PRRT2 is an important, frequent target of mismatch repair deficiency in cancer

    NARCIS (Netherlands)

    I. Teles Alves (Inês); Cano, D. (David); R. Böttcher (René); H.A.G.M. van der Korput (Hetty); W.N.M. Dinjens (Winand); G.W. Jenster (Guido); J. Trapman (Hans)

    2017-01-01

    textabstractThe DNA mismatch repair (MMR) system corrects DNA replication mismatches thereby contributing to the maintenance of genomic stability. MMR deficiency has been observed in prostate cancer but its impact on the genomic landscape of these tumours is not known. In order to identify MMR assoc

  19. Differential Distortion of Purine Substrates by Human and Plasmodium falciparum Hypoxanthine-Guanine Phosphoribosyltransferase to Catalyse the Formation of Mononucleotides.

    Science.gov (United States)

    Karnawat, Vishakha; Gogia, Spriha; Balaram, Hemalatha; Puranik, Mrinalini

    2015-07-20

    Plasmodium falciparum (Pf) hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is a potential therapeutic target. Compared to structurally homologous human enzymes, it has expanded substrate specificity. In this study, 9-deazapurines are used as in situ probes of the active sites of human and Pf HGPRTs. Through the use of these probes it is found that non-covalent interactions stabilise the pre-transition state of the HGPRT-catalysed reaction. Vibrational spectra reveal that the bound substrates are extensively distorted, the carbonyl bond of nucleobase moiety is weakened and the substrate is destabilised along the reaction coordinate. Raman shifts of the human and Pf enzymes are used to quantify the differing degrees of hydrogen bonding in the homologues. A decreased Raman cross-section in enzyme-bound 9-deazaguanine (9DAG) shows that the phenylalanine residue (Phe186 in human and Phe197 in Pf) of HGPRT stacks with the nucleobase. Differential loss of the Raman cross-section suggests that the active site is more compact in human HGPRT as compared to the Pf enzyme, and is more so in the phosphoribosyl pyrophosphate (PRPP) complex 9DAG-PRPP-HGPRT than in 9-deazahypoxanthine (9DAH)-PRPP-HGPRT.

  20. Novel assay for simultaneous measurement of pyridine mononucleotides synthesizing activities allows dissection of the NAD(+) biosynthetic machinery in mammalian cells.

    Science.gov (United States)

    Zamporlini, Federica; Ruggieri, Silverio; Mazzola, Francesca; Amici, Adolfo; Orsomando, Giuseppe; Raffaelli, Nadia

    2014-11-01

    The redox coenzyme NAD(+) is also a rate-limiting co-substrate for several enzymes that consume the molecule, thus rendering its continuous re-synthesis indispensable. NAD(+) biosynthesis has emerged as a therapeutic target due to the relevance of NAD(+) -consuming reactions in complex intracellular signaling networks whose alteration leads to many neurologic and metabolic disorders. Distinct metabolic routes, starting from various precursors, are known to support NAD(+) biosynthesis with tissue/cell-specific efficiencies, probably reflecting differential expression of the corresponding rate-limiting enzymes, i.e. nicotinamide phosphoribosyltransferase, quinolinate phosphoribosyltransferase, nicotinate phosphoribosyltransferase and nicotinamide riboside kinase. Understanding the contribution of these enzymes to NAD(+) levels depending on the tissue/cell type and metabolic status is necessary for the rational design of therapeutic strategies aimed at modulating NAD(+) availability. Here we report a simple, fast and sensitive coupled fluorometric assay that enables simultaneous determination of the four activities in whole-cell extracts and biological fluids. Its application to extracts from various mouse tissues, human cell lines and plasma yielded for the first time an overall picture of the tissue/cell-specific distribution of the activities of the various enzymes. The screening enabled us to gather novel findings, including (a) the presence of quinolinate phosphoribosyltransferase and nicotinamide riboside kinase in all examined tissues/cell lines, indicating that quinolinate and nicotinamide riboside are relevant NAD(+) precursors, and (b) the unexpected occurrence of nicotinate phosphoribosyltransferase in human plasma.

  1. Nicotinamide riboside kinases display redundancy in mediating nicotinamide mononucleotide and nicotinamide riboside metabolism in skeletal muscle cells

    Directory of Open Access Journals (Sweden)

    Rachel S. Fletcher

    2017-08-01

    Conclusions: These results identify skeletal muscle cells as requiring NAMPT to maintain NAD+ availability and reveal that NRK1 and 2 display overlapping function in salvage of exogenous NR and NMN to augment intracellular NAD+ availability.

  2. Acid Rain: The Scientific Challenge.

    Science.gov (United States)

    Godfrey, Paul J.

    1991-01-01

    Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

  3. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2003-01-01

    The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness.......The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness....

  4. Acid Rain: What's the Forecast?

    Science.gov (United States)

    Bybee, Rodger

    1984-01-01

    Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

  5. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2003-01-01

    The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness.......The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness....

  6. Protein and amino acid nutrition

    Science.gov (United States)

    Dairy cow protein and amino acid nutrition have a significant role in sustainable dairying. Protein, amino acids, and nitrogen are inextricably linked through effects in the rumen, metabolism of the cow, and environmental nutrient management. Feeding systems have been making progress toward emphasiz...

  7. Pantothenic acid (Vitamin B5)

    Science.gov (United States)

    ... vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B12 (cyanocobalamin), and folic acid. However, some products do ... Pantothenas, Calcium D-Pantothenate, Calcium Pantothenate, Complexe de Vitamines B, D-Calcium Pantothenate, D-Panthenol, D-Panthénol, ...

  8. Phosphorus derivatives of salicylic acid

    Science.gov (United States)

    Chvertkina, L. V.; Khoklov, P. S.; Mironov, Vladimir F.

    1992-10-01

    The present state of work on the methods of synthesis, chemical properties, and practical applications of phosphorus-containing derivatives of salicylic acid has been reviewed. The characteristics of the chemical transformations of cyclic and acyclic phosphorus derivatives of salicylic acid related to the coordination state of the phosphorus atom have been examined. The bibliography includes 158 references.

  9. utilisation of synthetic amino acids

    African Journals Online (AJOL)

    student

    intake, bodyweight gain, egg weight or efficiency of lysine utilisation, but ... When modelling the amino acid requirements of broiler breeder ... Two hundred and forty Cobb broiler breeder hens aged 27 weeks were housed in individual cages. ..... feeds with synthetic amino acids is of importance not only on nutritional and.

  10. Acid Rain: What's the Forecast?

    Science.gov (United States)

    Bybee, Rodger

    1984-01-01

    Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

  11. Acid Rain: The Scientific Challenge.

    Science.gov (United States)

    Godfrey, Paul J.

    1991-01-01

    Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

  12. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    Directory of Open Access Journals (Sweden)

    B.Syama Sundar

    2014-06-01

    Full Text Available Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation with Mn (VII in case of DL-Mandelic acid. The following order of reactivity is observed: DL-Mandelic acid > Phenyl acetic acid. The high reactivity of DL-Mandelic acid over phenyl acetic acid may be due to different mechanisms operating with the two substrates and benzaldehyde is the final product in both the cases.

  13. N-(3-Nitrophenylmaleamic acid

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-07-01

    Full Text Available In the title compound, C10H8N2O5, the molecule is slightly distorted from planarity. The molecular structure is stabilized by two intramolecular hydrogen bonds. The first is a short O—H...O hydrogen bond (H...O distance = 1.57 Å within the maleamic acid unit and the second is a C—H...O hydrogen bond (H...O distance = 2.24 Å which connects the amide group with the benzene ring. The nitro group is twisted by 6.2 (2° out of the plane of the benzene ring. The crystal structure manifests a variety of hydrogen bonding. The packing is dominated by a strong intermolecular N—H...O interaction which links the molecules into chains running along the b axis. The chains within a plane are further assembled by three additional types of intermolecular C—H...O hydrogen bonds to form a sheet parallel to the (overline{1}01 plane.

  14. Molten fatty acid based microemulsions.

    Science.gov (United States)

    Noirjean, Cecile; Testard, Fabienne; Dejugnat, Christophe; Jestin, Jacques; Carriere, David

    2016-06-21

    We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound.

  15. Pentadecanoic and Heptadecanoic Acids: Multifaceted Odd-Chain Fatty Acids.

    Science.gov (United States)

    Pfeuffer, Maria; Jaudszus, Anke

    2016-07-01

    The odd-chain fatty acids (OCFAs) pentadecanoic acid (15:0) and heptadecanoic acid (17:0), which account for only a small proportion of total saturated fatty acids in milk fat and ruminant meat, are accepted biomarkers of dairy fat intake. However, they can also be synthesized endogenously, for example, from gut-derived propionic acid (3:0). A number of studies have shown an inverse association between OCFA concentrations in human plasma phospholipids or RBCs and risk of type 2 diabetes and cardiovascular disease. We propose a possible involvement in metabolic regulation from the assumption that there is a link between 15:0 and 17:0 and the metabolism of other short-chain, medium-chain, and longer-chain OCFAs. The OCFAs 15:0 and 17:0 can be elongated to very-long-chain FAs (VLCFAs) such as tricosanoic acid (23:0) and pentacosanoic acid (25:0) in glycosphingolipids, particularly found in brain tissue, or can be derived from these VLCFAs. Their chains can be shortened, yielding propionyl-coenzyme A (CoA). Propionyl-CoA, by succinyl-CoA, can replenish the citric acid cycle (CAC) with anaplerotic intermediates and, thus, improve mitochondrial energy metabolism. Mitochondrial function is compromised in a number of disorders and may be impaired with increasing age. Optimizing anaplerotic intermediate availability for the CAC may help to cope with demands in times of increased metabolic stress and with aging. OCFAs may serve as substrates for synthesis of both odd-numbered VLCFAs and propionyl-CoA or store away excess propionic acid.

  16. Cluster (Cyanobacteria): 721123:897 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 721123:897 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur ca...rrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  17. Cluster (Cyanobacteria): 1160286:1409 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160286:1409 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur ...carrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  18. Cluster (Cyanobacteria): 213618:593 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 213618:593 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur ca...rrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  19. Cluster (Cyanobacteria): 1160284:691 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160284:691 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur c...arrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  20. Cluster (Cyanobacteria): 1160283:883 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160283:883 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur c...arrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  1. Cluster (Cyanobacteria): 1160279:288 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160279:288 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur c...arrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1125:2952 ...

  2. Cluster (Cyanobacteria): 1125:2952 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1125:2952 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur car...rier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1118:3229 1126:3426|1160279:287|1160279:288 ...

  3. Cluster (Cyanobacteria): 1160281:890 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160281:890 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur c...arrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  4. Cluster (Cyanobacteria): 1160285:1019 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160285:1019 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur ...carrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  5. Cluster (Cyanobacteria): 1160282:880 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160282:880 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur c...arrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  6. Cluster (Cyanobacteria): 1160280:42 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 1160280:42 putative adenylyltransferase/sulfurtransferase MoeZ (Includes: Sulfur ca...rrier protein CysO adenylyltransferase ; Sulfur carrier protein CysO sulfurtransferase) 1126:3426 ...

  7. NCBI nr-aa BLAST: CBRC-HSAP-05-0051 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-HSAP-05-0051 ref|YP_903576.1| nicotinate (nicotinamide) nucleotide adenylyltransferase [Candidatus Ruth...adenylyltransferase [Candidatus Ruthia magnifica str. Cm (Calyptogena magnifica)] YP_903576.1 1.1 34% ...

  8. NCBI nr-aa BLAST: CBRC-PTRO-06-0046 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PTRO-06-0046 ref|YP_903576.1| nicotinate (nicotinamide) nucleotide adenylyltransferase [Candidatus Ruth...adenylyltransferase [Candidatus Ruthia magnifica str. Cm (Calyptogena magnifica)] YP_903576.1 1.1 34% ...

  9. Fatty acid composition of selected prosthecate bacteria.

    Science.gov (United States)

    Carter, R N; Schmidt, J M

    1976-10-11

    The cellular fatty acid composition of 14 strains of Caulobacter speices and types, two species of Prosthecomicrobium, and two species of Asticcacaulis was determined by gas-liquid chromatography. In most of these bacteria, the major fatty acids were octadecenoic acid (C18:1), hexadecenoic acid (C16:1) and hexadecanoic acid (C16:0). Some cyclopropane and branched chain fatty acids were detected in addition to the straight chained acids. Hydroxytetradecanoic acid was an important component of P.enhydrum but significant amounts of hydroxy acids were not detected in other prosthecate bacteria examined.

  10. The Property and Application of Arachidonic Acid

    Institute of Scientific and Technical Information of China (English)

    王相勤; 姚建铭; 袁成凌; 王纪; 余增亮

    2002-01-01

    Arachidonic acid (AA) is one of the most important PUFAs (polyunsaturated fatty acids) in human body. A high-yield arachidonic acid-producing strain (mortierella alpina) was selected by ion implantation (the relative content of arachidonic acid is 70.2% among all fatty acids). This paper mainly introduced the structure, distribution, source, physiologic healthcare function and application of AA.

  11. Terahertz spectrum of gallic acid

    Science.gov (United States)

    Wu, Meng; Zhao, Guozhong; Wang, Haiyan; Liang, Chengshen

    2009-11-01

    Gallic acid is natural polyphenol compound found in many green plants. More and more experiments have demonstrated that the gallic acid has comprehensive applications. In the field of medicine, the gallic acid plays an important role in antianaphylaxis, antineoplastic, antimycotic, anti-inflammatory, antivirotic, antiasthmatic and inhibiting the degradation of insulin. It also has a lot of applications in chemical industry, food industry and light industry. So it is important to study the terahertz time-domain spectroscopy of gallic acid. Terahertz time-domain spectroscopy (THz-TDS) is a new coherent spectral technology based on the femtosecond laser. In this work, the spectral characteristics of gallic acid in the range of 0.4 THz to 2.6 THz have been measured by THz-TDS. We obtained its absorption and refraction spectra at room temperature. The vibration absorption spectrum of the single molecule between 0.4 THz and 2.6 THz is simulated based on the Density Functional Theory (DFT). It is found that the gallic acid has the spectral response to THz wave in this frequency range. The results show the abnormal dispersion at 1.51 THz and 2.05 THz. These results can be used in the qualitative analysis of gallic acid and the medicine and food inspection.

  12. Amino acids and immune function.

    Science.gov (United States)

    Li, Peng; Yin, Yu-Long; Li, Defa; Kim, Sung Woo; Wu, Guoyao

    2007-08-01

    A deficiency of dietary protein or amino acids has long been known to impair immune function and increase the susceptibility of animals and humans to infectious disease. However, only in the past 15 years have the underlying cellular and molecular mechanisms begun to unfold. Protein malnutrition reduces concentrations of most amino acids in plasma. Findings from recent studies indicate an important role for amino acids in immune responses by regulating: (1) the activation of T lymphocytes, B lymphocytes, natural killer cells and macrophages; (2) cellular redox state, gene expression and lymphocyte proliferation; and (3) the production of antibodies, cytokines and other cytotoxic substances. Increasing evidence shows that dietary supplementation of specific amino acids to animals and humans with malnutrition and infectious disease enhances the immune status, thereby reducing morbidity and mortality. Arginine, glutamine and cysteine precursors are the best prototypes. Because of a negative impact of imbalance and antagonism among amino acids on nutrient intake and utilisation, care should be exercised in developing effective strategies of enteral or parenteral provision for maximum health benefits. Such measures should be based on knowledge about the biochemistry and physiology of amino acids, their roles in immune responses, nutritional and pathological states of individuals and expected treatment outcomes. New knowledge about the metabolism of amino acids in leucocytes is critical for the development of effective means to prevent and treat immunodeficient diseases. These nutrients hold great promise in improving health and preventing infectious diseases in animals and humans.

  13. Phytic acid in green leaves.

    Science.gov (United States)

    Hadi Alkarawi, H; Zotz, G

    2014-07-01

    Phytic acid or phytate, the free-acid form of myo-inositolhexakiphosphate, is abundant in many seeds and fruits, where it represents the major storage form of phosphorus. Although also known from other plant tissues, available reports on the occurrence of phytic acid, e.g. in leaves, have never been compiled, nor have they been critically reviewed. We found 45 published studies with information on phytic acid content in leaves. Phytic acid was almost always detected when studies specifically tried to detect it, and accounted for up to 98% of total P. However, we argue that such extreme values, which rival findings from storage organs, are dubious and probably result from measurement errors. Excluding these high values from further quantitative analysis, foliar phytic acid-P averaged 2.3 mg·g(-1) , and represented, on average, 7.6% of total P. Remarkably, the ratio of phytic acid-P to total P did not increase with total P, we even detected a negative correlation of the two variables within one species, Manihot esculenta. This enigmatic finding warrants further attention.

  14. Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.

    Science.gov (United States)

    Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

    2012-11-01

    A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.

  15. Pyroligneous acid-the smoky acidic liquid from plant biomass.

    Science.gov (United States)

    Mathew, Sindhu; Zakaria, Zainul Akmar

    2015-01-01

    Pyroligneous acid (PA) is a complex highly oxygenated aqueous liquid fraction obtained by the condensation of pyrolysis vapors, which result from the thermochemical breakdown or pyrolysis of plant biomass components such as cellulose, hemicellulose, and lignin. PA produced by the slow pyrolysis of plant biomass is a yellowish brown or dark brown liquid with acidic pH and usually comprises a complex mixture of guaiacols, catechols, syringols, phenols, vanillins, furans, pyrans, carboxaldehydes, hydroxyketones, sugars, alkyl aryl ethers, nitrogenated derivatives, alcohols, acetic acid, and other carboxylic acids. The phenolic components, namely guaiacol, alkyl guaiacols, syringol, and alkyl syringols, contribute to the smoky odor of PA. PA finds application in diverse areas, as antioxidant, antimicrobial, antiinflammatory, plant growth stimulator, coagulant for natural rubber, and termiticidal and pesticidal agent; is a source for valuable chemicals; and imparts a smoky flavor for food.

  16. ELECTRODIALYTIC PRODUCTION OF HYPOPHOSPHOROUS ACID

    Institute of Scientific and Technical Information of China (English)

    CHENG Jianzhong; ZHANG Yingzhe; ZHANG Baogui; ZHANG Zhengpu

    2001-01-01

    Disclosed is a method of preparing hypophosphorous acid comprising contacting an insoluble anode with an aqueous solution of hypophosphite anions and applying a direct current through the insoluble anode to a cathode in electrical contact with the aqueous solution to generate H+ ions in the aqueous solution thereby forming a hypophosphorous acid solution. The process is simple,low cost and high efficient, which can be tied into an existing process for producing sodium hypophosphite wherein the product of sodium hypophosphite process is used as a starting material in the hypophosphorous acid process.

  17. REACTIVE EXTRACTION OF TARTARIC ACID

    Directory of Open Access Journals (Sweden)

    Natalia Marchitan

    2009-12-01

    Full Text Available The present paper describes the results of reactive extraction of tartaric acid in model systems, which can be used for its separation from secondary wine products. As extractant have been used a normal/isododecyl mixed secondary amine Amberlite LA-2. The following parameters of the separation process have been varied: nature of diluent and modifier; modifier concentration; concentration, temperature and pH of the tartaric acid solution and the stirring time, and the work intervals have been established. It was concluded that in determinated conditions the extent of tartaric acid extraction attains value 85-95%.

  18. Amino Acids from a Comet

    Science.gov (United States)

    Cook, Jamie Elisla

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

  19. Enhanced acid tolerance of Rhizopus oryzae during fumaric acid production.

    Science.gov (United States)

    Liu, Ying; Lv, Chunwei; Xu, Qing; Li, Shuang; Huang, He; Ouyang, Pingkai

    2015-02-01

    Ensuring a suitable pH in the culture broth is a major problem in microorganism-assisted industrial fermentation of organic acids. To address this issue, we investigated the physiological changes in Rhizopus oryzae at different extracellular pH levels and attempted to solve the issue of cell shortage under low pH conditions. We compared various parameters, such as membrane fatty acids' composition, intracellular pH, and adenosine triphosphate (ATP) concentration. It was found that the shortage of intracellular ATP might be the main reason for the low rate of fumaric acid production by R. oryzae under low pH conditions. When 1 g/l citrate was added to the culture medium at pH 3.0, the intracellular ATP concentration increased from 0.4 to 0.7 µmol/mg, and the fumaric acid titer was enhanced by 63% compared with the control (pH 3.0 without citrate addition). The final fumaric acid concentration at pH 3.0 reached 21.9 g/l after 96 h of fermentation. This strategy is simple and feasible for industrial fumaric acid production under low pH conditions.

  20. Molar extinction coefficients of some fatty acids

    Science.gov (United States)

    Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

    2002-10-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

  1. Omega-3 Fatty Acids during Pregnancy

    Science.gov (United States)

    OMEGA-3 FATTY ACIDS DURING PREGNANCY S HARE W ITH W OMEN OMEGA-3 FATTY ACIDS DURING PREGNANCY During pregnancy, your ... the foods you eat and vitamins you take. Omega-3 fatty acids (omega-3s) are an important ...

  2. Folic Acid: MedlinePlus Health Topic

    Science.gov (United States)

    ... Article: Folic Acid Supplementation for the Prevention of Neural Tube Defects:... Article: Folic Acid Supplementation for the Prevention of Neural Tube Defects:... Article: Folic Acid Supplementation for Prevention of ...

  3. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  4. PHYSIOLOGY OF ACID BASE BALANCE

    Directory of Open Access Journals (Sweden)

    Awati

    2014-12-01

    Full Text Available Acid-base, electrolyte, and metabolic disturbances are common in the intensive care unit. Almost all critically ill patients often suffer from compound acid-base and electrolyte disorders. Successful evaluation and management of such patients requires recognition of common patterns (e.g., metabolic acidosis and the ability to dissect one disorder from another. The intensivists needs to identify and correct these condition with the easiest available tools as they are the associated with multiorgan failure. Understanding the elements of normal physiology in these areas is very important so as to diagnose the pathological condition and take adequate measures as early as possible. Arterial blood gas analysis is one such tool for early detection of acid base disorder. Physiology of acid base is complex and here is the attempt to simplify it in our day to day application for the benefit of critically ill patients.

  5. Bile acid sequestrants for cholesterol

    Science.gov (United States)

    ... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

  6. Compact oleic acid in HAMLET.

    Science.gov (United States)

    Fast, Jonas; Mossberg, Ann-Kristin; Nilsson, Hanna; Svanborg, Catharina; Akke, Mikael; Linse, Sara

    2005-11-07

    HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a complex between alpha-lactalbumin and oleic acid that induces apoptosis in tumor cells, but not in healthy cells. Heteronuclear nuclear magnetic resonance (NMR) spectroscopy was used to determine the structure of 13C-oleic acid in HAMLET, and to study the 15N-labeled protein. Nuclear Overhauser enhancement spectroscopy shows that the two ends of the fatty acid are in close proximity and close to the double bond, indicating that the oleic acid is bound to HAMLET in a compact conformation. The data further show that HAMLET is a partly unfolded/molten globule-like complex under physiological conditions.

  7. Low acid producing solid propellants

    Science.gov (United States)

    Bennett, Robert R.

    1995-01-01

    The potential environmental effects of the exhaust products of conventional rocket propellants have been assessed by various groups. Areas of concern have included stratospheric ozone, acid rain, toxicity, air quality and global warming. Some of the studies which have been performed on this subject have concluded that while the impacts of rocket use are extremely small, there are propellant development options which have the potential to reduce those impacts even further. This paper discusses the various solid propellant options which have been proposed as being more environmentally benign than current systems by reducing HCI emissions. These options include acid neutralized, acid scavenged, and nonchlorine propellants. An assessment of the acid reducing potential and the viability of each of these options is made, based on current information. Such an assessment is needed in order to judge whether the potential improvements justify the expenditures of developing the new propellant systems.

  8. Biotechnological production of citric acid

    Directory of Open Access Journals (Sweden)

    Belén Max

    2010-12-01

    Full Text Available This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid.

  9. Antibiofilm Properties of Acetic Acid

    Science.gov (United States)

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup; Nielsen, Anne K.; Johansen, Helle Krogh; Homøe, Preben; Høiby, Niels; Givskov, Michael; Kirketerp-Møller, Klaus

    2015-01-01

    Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms. PMID:26155378

  10. Nucleic Acid-Based Nanoconstructs

    Science.gov (United States)

    Focuses on the design, synthesis, characterization, and development of spherical nucleic acid constructs as effective nanotherapeutic, single-entity agents for the treatment of glioblastoma multiforme and prostate cancers.

  11. Anthranilic acid derivatives from Inula japonica

    Institute of Scientific and Technical Information of China (English)

    Jiang Jiang Qin; Hui Zi Jin; Jian Jun Fu; Xiao Jia Hu; Yan Zhu; Yun Heng Shen; Shi Kai Yan; Wei Dong Zhang

    2008-01-01

    Three new anthranilic acid derivatives, N-heneicosanoylanthranilic acid (1b), N-tricosanoylanthranilic acid (1d), N-tetra-cosanoylanthranilic acid (1e), and two known N-arachidylanthranilic acid (1a) and N-docosanoylanthranilic acid (1c) were isolatedfrom the aerial parts of Inula japonica Thunb. Their structures were established by spectroscopic and chemical methods.2008 Hui Zi Jin. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  12. 21 CFR 184.1009 - Adipic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Adipic acid. 184.1009 Section 184.1009 Food and... Substances Affirmed as GRAS § 184.1009 Adipic acid. (a) Adipic acid (C6H10O4, CAS Reg. No. 00124-04-9) is also known as 1,4-butanedicarboxylic acid or hexane-dioic acid. It is prepared by nitric acid oxidation...

  13. 21 CFR 172.862 - Oleic acid derived from tall oil fatty acids.

    Science.gov (United States)

    2010-04-01

    ... FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.862 Oleic acid derived from tall oil fatty acids. The food additive oleic acid derived from tall oil fatty acids may be safely used in food and as... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Oleic acid derived from tall oil fatty acids....

  14. Simultaneous analysis of small organic acids and humic acids using high performance size exclusion chromatography

    NARCIS (Netherlands)

    Qin, X.P.; Liu, F.; Wang, G.C.; Weng, L.P.

    2012-01-01

    An accurate and fast method for simultaneous determination of small organic acids and much larger humic acids was developed using high performance size exclusion chromatography. Two small organic acids, i.e. salicylic acid and 2,3-dihydroxybenzoic acid, and one purified humic acid material were used

  15. Cyanuric acid-epichlorohydrin prepolymers

    OpenAIRE

    Pedroso, L. M.; Simões, P; Portugal, A.

    2006-01-01

    In this study, we investigated the reaction of cyanuric acid and epichlorohydrin (ECH). SnCl4 was used as a catalyst. Several reaction conditions were tested, and the products were analyzed by means of Fourier transform infrared and 1H-NMR spectroscopy, hydroxyl group content, molar mass, elemental and thermal analysis, viscosity, and density. ECH reacted with the amine groups of the cyanuric acid ring to form lateral chains that contained chloroalkyl and hydroxyl end groups. Full substitutio...

  16. Nucleic Acid Aptamers Against Proteases

    DEFF Research Database (Denmark)

    Dupont, D M; Andersen, L M; Bøtkjær, Kenneth Alrø

    2011-01-01

    Proteases are potential or realized therapeutic targets in a wide variety of pathological conditions. Moreover, proteases are classical subjects for studies of enzymatic and regulatory mechanisms. We here review the literature on nucleic acid aptamers selected with proteases as targets. Designing...... strategies and of new principles for regulating the activity of the inhibitory action of aptamers of general interest to researchers working with nucleic acid aptamers...

  17. Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Kessel, Kurt R.

    2016-01-01

    Corrosion is an extensive problem that affects the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. It is vital to reduce corrosion costs and risks in a sustainable manner. The primary objective of this effort is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys.

  18. Biocatalytic reduction of carboxylic acids.

    Science.gov (United States)

    Napora-Wijata, Kamila; Strohmeier, Gernot A; Winkler, Margit

    2014-06-01

    An increasing demand for non-petroleum-based products is envisaged in the near future. Carboxylic acids such as citric acid, succinic acid, fatty acids, and many others are available in abundance from renewable resources and they could serve as economic precursors for bio-based products such as polymers, aldehyde building blocks, and alcohols. However, we are confronted with the problem that carboxylic acid reduction requires a high level of energy for activation due to the carboxylate's thermodynamic stability. Catalytic processes are scarce and often their chemoselectivity is insufficient. This review points at bio-alternatives: currently known enzyme classes and organisms that catalyze the reduction of carboxylic acids are summarized. Two totally distinct biocatalyst lines have evolved to catalyze the same reaction: aldehyde oxidoreductases from anaerobic bacteria and archea, and carboxylate reductases from aerobic sources such as bacteria, fungi, and plants. The majority of these enzymes remain to be identified and isolated from their natural background in order to evaluate their potential as industrial biocatalysts.

  19. [Women's knowledge of folic acid].

    Science.gov (United States)

    Salgues, Mathilde; Damase-Michel, Christine; Montastruc, Jean-Louis; Lacroix, Isabelle

    2017-06-01

    Many trials have shown that folic acid supplementation before and during pregnancy reduces the risk of neural tube defects in general population. We investigated the knowledge of folic acid in women of child-bearing age. Women of child-bearing age were interviewed by 20 pharmacists living in Haute-Garonne between January and February 2014. One hundred ninety-six women were included in the present study. Out of them, 36% of women never heard of folic acid and 82% were not aware of its benefits. Knowledge was higher in older women, women in a couple and women with higher educational level (Pfolic acid during pregnancy. Moreover, previous studies have shown that French women have low use of folic acid during peri-conceptional period. Information of general population will be required for a better prevention of folic acid-preventable NTDs. Copyright © 2016 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

  20. SATURATED PICRIC ACID PREVENTS AUTOPHAGIA

    Directory of Open Access Journals (Sweden)

    V Rahimi-Movaghar

    2008-08-01

    Full Text Available "nThe dysesthesia and paresthesia that occurs in laboratory rats after spinal cord injury (SCI results in autophagia. This self-destructive behavior interferes with functional assessments in designed studies and jeopardizes the health of the injured rat. In this study, we evaluated role of saturated picric acid in the prevention of autophagia and self-mutilation. All rats were anesthetized with an intraperitoneal injection of a mixture of ketamine (100 mg/kg and xylazine (10 mg/kg for the SCI procedures. In the first 39 rats, no solution applied to the hind limbs, but in the next 26 cases, we smeared the saturated picric acid on the tail, lower extremities, pelvic, and abdomen of the rats immediately after SCI. In the rats without picric acid, 23 rats died following autophagia, but in the 26 rats with picric acid, there was no autophagia (P < 0.001. Picric acid side effects in skin and gastrointestinal signs such as irritation, redness and diarrhea were not seen in any rat. Saturated picric acid is a topical solution that if used appropriately and carefully, might be safe and effectively prevents autophagia and self-mutilation. When the solution is applied to the lower abdomen and limbs, we presume that its bitterness effectively prevents the rat from licking and biting the limb.

  1. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  2. Evaluation of ascorbic acid in protecting labile folic acid derivatives.

    Science.gov (United States)

    Wilson, S D; Horne, D W

    1983-11-01

    The use of ascorbic acid as a reducing agent to protect labile, reduced derivatives of folic acid has been evaluated by high-performance liquid chromatographic separations and Lactobacillus casei microbiological assay of eluate fractions. Upon heating for 10 min at 100 degrees C, solutions of tetrahydropteroylglutamic acid (H4PteGlu) in 2% sodium ascorbate gave rise to 5,10-methylene-H4PteGlu and 5-methyl-H4PteGlu. H2PteGlu acid gave rise to 5-methyl-H4PteGlu and PteGlu. 10-Formyl-H4PteGlu gave rise to 5-formyl-H4PteGlu and 10-formyl-PteGlu. 5-Formyl-H4-PteGlu gave rise to a small amount of 10-formyl-PteGlu. 5-Methyl-H4PteGlu and PteGlu appeared stable to these conditions. These interconversions were not seen when solutions of these folate derivatives were kept at 0 degrees C in 1% ascorbate. These observations indicate that elevated temperatures are necessary for the interconversions of folates in ascorbate solutions. Assays of ascorbic acid solutions indicated the presence of formaldehyde (approximately equal to 6 mM). This was confirmed by the identification of 3,5-diacetyl-1,4-dihydrolutidine by UV, visible, and fluorescence spectroscopy and by thin-layer chromatography of chloroform extracts of the reaction mixture of ascorbic acid solutions, acetylacetone, and ammonium acetate. These results indicate that solutions of sodium ascorbate used at elevated temperatures are not suitable for extracting tissue for the subsequent assay of the individual folic acid derivatives.

  3. Performance of Different Acids on Sandstone Formations

    Directory of Open Access Journals (Sweden)

    M. A. Zaman

    2013-12-01

    Full Text Available Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Some of these reactions may result in formation damage. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. It is a mixture of hydrofluoric (HF and hydrochloric (HCl acids designed to dissolve clays and siliceous fines accumulated in the near-wellbore region. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50% to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid – Hydrofluoric with Concentration (3% HF – 12% HCl. This paper presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results calculated are porosity, permeability, and FESEM Analysis and Strength tests. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  4. Vanadocene reactions with hydroxy acids. [Hydroxy acids: acetylsalicylic, gallic, lactic, salicyclic, orotic,. gamma. -hydroxybutyric acids

    Energy Technology Data Exchange (ETDEWEB)

    Latyaeva, V.N.; Lineva, A.N.; Zimina, S.V.; Ehllert, O.G.; Arsen' eva, T.I. (Gor' kovskij Meditsinskij Inst. (USSR))

    1984-03-01

    To prepare a series of vanadium cyclopentadienylcarboxylates soluble in water, the vanadocene reactions with lactic, ..gamma..-oxybutyric-, salicylic,- gallic-, orotic-, and acetylsalicylic acids have been studied. To determine the influence of cyclopentadienyl groups, bound with a vanadium atom, on the physiological activity of the complexes formed, vanadium halides are made to react with lactic acid. Only the vanadocene reaction with orotic acid was conducted in an aqueous medium, other interactions were realized in the diethyl ether, toluene, T, H, P medium. The interaction of vanadocene and vanadium halides with lactic-, salicylic-, acetylsalicylic- and gallic acids was found to lead to the formation of water-soluble vanadium complexes of Cp/sub 2/, VOCOR or CpV (OCOR)/sub 2/ type. The data on the produced compounds yield, their IR spectra, decomposition temperatures, solubility, effective magnetic moments are presented.

  5. An Efficient Procedure for Esterification of Aryloxyacetic Acid and Arylthioacetic Acid Catalyzed by Silica Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    LI,Hong-Ya; LI,Ji-Tai; LI,Hui-Zhang

    2004-01-01

    @@ Aryloxyacetate and arylthioacetate are wildly used in herbicides, plant regulator and insecticides. Recently, Wille et al. have reported that methyl aryloxyacetate is an efficient agent to prevent and treat allergic contact dermatitis.[1] The most popular synthesis is by heating sodium phenoxide (mercaptide) with ethyl chloroacetate in DMF,[2] or by the esterification of acid with alcohol using concentrated H2SO4 as catalyst.[3] In this paper, synthesis of aryloxyacetate and aryl thioacetate from aryloxyacetic acid and arylthioacetic acid respectively in ether catalyzed by silica sulfuric acid in 83%~94% yields is described. The catalyst is reused for 3 times without significant loss of activity (Entry 4). Compared with common procedures, the present procedure possesses the advantages of the operational simplicity, short reaction time,less-corrosion, high yield and reusable catalyst.

  6. Fatty acid-amino acid conjugates diversification in lepidopteran caterpillars.

    Science.gov (United States)

    Yoshinaga, Naoko; Alborn, Hans T; Nakanishi, Tomoaki; Suckling, David M; Nishida, Ritsuo; Tumlinson, James H; Mori, Naoki

    2010-03-01

    Fatty acid amino acid conjugates (FACs) have been found in noctuid as well as sphingid caterpillar oral secretions; in particular, volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants. These induced volatiles, in turn, attract natural enemies of the caterpillars. In a previous study, we showed that N-linolenoyl-L-glutamine in larval Spodoptera litura plays an important role in nitrogen assimilation which might be an explanation for caterpillars synthesizing FACs despite an increased risk of attracting natural enemies. However, the presence of FACs in lepidopteran species outside these families of agricultural interest is not well known. We conducted FAC screening of 29 lepidopteran species, and found them in 19 of these species. Thus, FACs are commonly synthesized through a broad range of lepidopteran caterpillars. Since all FAC-containing species had N-linolenoyl-L-glutamine and/or N-linoleoyl-L-glutamine in common, and the evolutionarily earliest species among them had only these two FACs, these glutamine conjugates might be the evolutionarily older FACs. Furthermore, some species had glutamic acid conjugates, and some had hydroxylated FACs. Comparing the diversity of FACs with lepidopteran phylogeny indicates that glutamic acid conjugates can be synthesized by relatively primitive species, while hydroxylation of fatty acids is limited mostly to larger and more developed macrolepidopteran species.

  7. Molecular screening of wine lactic acid bacteria degrading hydroxycinnamic acids.

    Science.gov (United States)

    de las Rivas, Blanca; Rodríguez, Héctor; Curiel, José Antonio; Landete, José María; Muñoz, Rosario

    2009-01-28

    The potential to produce volatile phenols from hydroxycinnamic acids was investigated for lactic acid bacteria (LAB) isolated from Spanish grape must and wine. A PCR assay was developed for the detection of LAB that potentially produce volatile phenols. Synthetic degenerate oligonucleotides for the specific detection of the pdc gene encoding a phenolic acid decarboxylase were designed. The pdc PCR assay amplifies a 321 bp DNA fragment from phenolic acid decarboxylase. The pdc PCR method was applied to 85 strains belonging to the 6 main wine LAB species. Lactobacillus plantarum, Lactobacillus brevis, and Pediococcus pentosaceus strains produce a positive response in the pdc PCR assay, whereas Oenococcus oeni, Lactobacillus hilgardii, and Leuconostoc mesenteroides strains did not produce the expected PCR product. The production of vinyl and ethyl derivatives from hydroxycinnamic acids in culture media was determined by high-performance liquid chromatography. A relationship was found between pdc PCR amplification and volatile phenol production, so that the LAB strains that gave a positive pdc PCR response produce volatile phenols, whereas strains that did not produce a PCR amplicon did not produce volatile phenols. The proposed method could be useful for a preliminary identification of LAB strains able to produce volatile phenols in wine.

  8. Gas-Phase Acidities of Phosphorylated Amino Acids.

    Science.gov (United States)

    Stover, Michele L; Plummer, Chelsea E; Miller, Sean R; Cassady, Carolyn J; Dixon, David A

    2015-11-19

    Gas-phase acidities and heats of formation have been predicted at the G3(MP2)/SCRF-COSMO level of theory for 10 phosphorylated amino acids and their corresponding amides, including phospho-serine (pSer), -threonine (pThr), and -tyrosine (pTyr), providing the first reliable set of these values. The gas-phase acidities (GAs) of the three named phosphorylated amino acids and their amides have been determined using proton transfer reactions in a Fourier transform ion cyclotron mass spectrometer. Excellent agreement was found between the experimental and predicted GAs. The phosphate group is the deprotonation site for pSer and pThr and deprotonation from the carboxylic acid generated the lowest energy anion for pTyr. The infrared spectra were calculated for six low energy anions of pSer, pThr, and pTyr. For deprotonated pSer and pThr, good agreement is found between the experimental IRMPD spectra and the calculated spectra for our lowest energy anion structure. For pTyr, the IR spectra for a higher energy phosphate deprotonated structure is in good agreement with experiment. Additional experiments tested electrospray ionization (ESI) conditions for pTyr and determined that variations in solvent, temperature, and voltage can result in a different experimental GA value, indicating that ESI conditions affect the conformation of the pTyr anion.

  9. [Regulating acid stress resistance of lactic acid bacteria--a review].

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-07-04

    As cell factories, lactic acid bacteria are widely used in food, agriculture, pharmaceutical and other industries. Acid stress is one the important survival challenges encountered by lactic acid bacteria both in fermentation process and in the gastrointestinal tract. Recently, the development of systems biology and metabolic engineering brings unprecedented opportunity for further elucidating the acid tolerance mechanisms and improving the acid stress resistance of lactic acid bacteria. This review addresses physiological mechanisms of lactic acid bacteria during acid stress. Moreover, strategies to improve the acid stress resistance of lactic acid were proposed.

  10. Extractive fermentation of acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Busche, R.M. [Bio En-Gene-Er Associates, Inc., Wilmington, DE (United States)

    1991-12-31

    In this technoeconomic evaluation of the manufacture of acetic acid by fermentation, the use of the bacterium: Acetobacter suboxydans from the old vinegar process was compared with expected performance of the newer Clostridium thermoaceticum bacterium. Both systems were projected to operate as immobilized cells in a continuous, fluidized bed bioreactor, using solvent extraction to recover the product. Acetobacter metabolizes ethanol aerobically to produce acid at 100 g/L in a low pH medium. This ensures that the product is in the form of a concentrated extractable free acid, rather than as an unextractable salt. Unfortunately, yields from glucose by way of the ethanol fermentation are poor, but near the biological limits of the organisms involved. Conversely, C. thermoaceticum is a thermophilic anaerobe that operates at high fermentation rates on glucose at neutral pH to produce acetate salts directly in substantially quantitative yields. However, it is severely inhibited by product, which restricts concentration to a dilute 20 g/L. An improved Acetobacter system operating with recycled cells at 50 g/L appears capable of producing acid at $0.38/lb, as compared with a $0.29/lb price for synthetic acid. However, this system has only a limited margin for process improvement. The present Clostridium system cannot compete, since the required selling price would be $0.42/lb. However, if the organism could be adapted to tolerate higher product concentrations at acid pH, selling price could be reduced to $0.22/lb, or about 80% of the price of synthetic acid.

  11. Biological Activities of the Essential Oil from Erigeron floribundus

    Directory of Open Access Journals (Sweden)

    Riccardo Petrelli

    2016-08-01

    Full Text Available Erigeron floribundus (Asteraceae is an herbaceous plant widely used in Cameroonian traditional medicine to treat various diseases of microbial and non-microbial origin. In the present study, we evaluated the in vitro biological activities displayed by the essential oil obtained from the aerial parts of E. floribundus, namely the antioxidant, antimicrobial and antiproliferative activities. Moreover, we investigated the inhibitory effects of E. floribundus essential oil on nicotinate mononucleotide adenylyltransferase (NadD, a promising new target for developing novel antibiotics, and Trypanosoma brucei, the protozoan parasite responsible for Human African trypanosomiasis. The essential oil composition was dominated by spathulenol (12.2%, caryophyllene oxide (12.4% and limonene (8.8%. The E. floribundus oil showed a good activity against Staphylococcus aureus (inhibition zone diameter, IZD of 14 mm, minimum inhibitory concentration, MIC of 512 µg/mL. Interestingly, it inhibited the NadD enzyme from S. aureus (IC50 of 98 µg/mL, with no effects on mammalian orthologue enzymes. In addition, T. brucei proliferation was inhibited with IC50 values of 33.5 µg/mL with the essential oil and 5.6 µg/mL with the active component limonene. The essential oil exhibited strong cytotoxicity on HCT 116 colon carcinoma cells with an IC50 value of 14.89 µg/mL, and remarkable ferric reducing antioxidant power (tocopherol-equivalent antioxidant capacity, TEAC = 411.9 μmol·TE/g.

  12. Targeting NAD+ metabolism in the human malaria parasite Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Jessica K O'Hara

    Full Text Available Nicotinamide adenine dinucleotide (NAD+ is an essential metabolite utilized as a redox cofactor and enzyme substrate in numerous cellular processes. Elevated NAD+ levels have been observed in red blood cells infected with the malaria parasite Plasmodium falciparum, but little is known regarding how the parasite generates NAD+. Here, we employed a mass spectrometry-based metabolomic approach to confirm that P. falciparum lacks the ability to synthesize NAD+ de novo and is reliant on the uptake of exogenous niacin. We characterized several enzymes in the NAD+ pathway and demonstrate cytoplasmic localization for all except the parasite nicotinamidase, which concentrates in the nucleus. One of these enzymes, the P. falciparum nicotinate mononucleotide adenylyltransferase (PfNMNAT, is essential for NAD+ metabolism and is highly diverged from the human homolog, but genetically similar to bacterial NMNATs. Our results demonstrate the enzymatic activity of PfNMNAT in vitro and demonstrate its ability to genetically complement the closely related Escherichia coli NMNAT. Due to the similarity of PfNMNAT to the bacterial enzyme, we tested a panel of previously identified bacterial NMNAT inhibitors and synthesized and screened twenty new derivatives, which demonstrate a range of potency against live parasite culture. These results highlight the importance of the parasite NAD+ metabolic pathway and provide both novel therapeutic targets and promising lead antimalarial compounds.

  13. Production and purification of avian antibodies (IgYs from inclusion bodies of a recombinant protein central in NAD+ metabolism

    Directory of Open Access Journals (Sweden)

    Paula A. Moreno-González

    2013-08-01

    Full Text Available The use of hens for the production of polyclonal antibodies reduces animal intervention and moreover yields a higher quantity of antibodies than other animal models.  The phylogenetic distance between bird and mammal antigens, often leads to more specific avian antibodies than their mammalian counterparts.Since a large amount of antigen is required for avian antibody production, the use of recombinant proteins for this procedure has been growing faster over the last years. Nevertheless, recombinant protein production through heterologous systems frequently prompts the protein to precipitate, forming insoluble aggregates of limited utility (inclusion bodies. A methodology for the production of avian polyclonal antibodies, using recombinant protein from inclusion bodies is presented in this article.In order to produce the antigen, a recombinant Nicotinamide mononucleotide adenylyltransferase from Giardia intestinalis (His-GiNMNAT was expressed in Escherichia coli.  The protein was purified through solubilization from inclusion bodies prior to its renaturalization.  Antibodies were purified from egg yolk of immunized hens by water dilution, followed by ammonium sulfate precipitation and thiophilic affinity chromatography.The purified antibodies were tested against His-GiNMNAT protein in Western blot essays. From one egg yolk, 14.4 mg of highly pure IgY were obtained; this antibody was able to detect 15ng of His-GiNMNAT.  IgY specificity was improved by means of antigen affinity purification, allowing its use for parasite protein recognition.

  14. SIRT1 and stem cells: In the forefront with cardiovasculardisease, neurodegeneration and cancer

    Institute of Scientific and Technical Information of China (English)

    Kenneth Maiese

    2015-01-01

    Cardiovascular disease, nervous system disorders, andcancer in association with other diseases such as diabetesmellitus result in greater than sixty percent of the globalannual deaths. These noncommunicable diseases alsoaffect at least one-third of the population in low andmiddle-income countries and lead to hypertension,elevated cholesterol, malignancy, and neurodegenerativedisorders such as Alzheimer's disease and stroke. Withthe climbing lifespan of the world's population, increasedprevalence of these disorders is expected requiringthe development of new therapeutic strategies againstthese disabling disease entities. Targeting stem cellproliferation for cardiac disease, vascular disorders,cancer, and neurodegenerative disorders is receivinggreat enthusiasm, especially those that focus uponSIRT1, a mammalian homologue of the yeast silentinformation regulator-2. Modulation of the cellular activityof SIRT1 can involve oversight by nicotinamide/nicotinicacid mononucleotide adenylyltransferase, mammalianforkhead transcription factors, mechanistic of rapamycinpathways, and cysteine-rich protein 61, connective tissuegrowth factor, and nephroblastoma over-expressedgene family members that can impact cytoprotectiveoutcomes. Ultimately, the ability of SIRT1 to controlthe programmed cell death pathways of apoptosis andautophagy can determine not only cardiac, vascular, andneuronal stem cell development and longevity, but alsothe onset of tumorigenesis and the resistance againstchemotherapy. SIRT1 therefore has a critical role andholds exciting prospects for new therapeutic strategiesthat can offer reparative processes for cardiac, vascular,and nervous system degenerative disorders as well astargeted control of aberrant cell growth during cancer.

  15. NMNAT3 is involved in the protective effect of SIRT3 in Ang II-induced cardiac hypertrophy.

    Science.gov (United States)

    Yue, Zhongbao; Ma, Yunzi; You, Jia; Li, Zhuoming; Ding, Yanqing; He, Ping; Lu, Xia; Jiang, Jianmin; Chen, Shaorui; Liu, Peiqing

    2016-10-01

    Pathological cardiac hypertrophy is a maladaptive response in a variety of organic heart disease (OHD), which is characterized by mitochondrial dysfunction that results from disturbed energy metabolism. SIRT3, a mitochondria-localized sirtuin, regulates global mitochondrial lysine acetylation and preserves mitochondrial function. However, the mechanisms by which SIRT3 regulates cardiac hypertrophy remains to be further elucidated. In this study, we firstly demonstrated that expression of SIRT3 was decreased in Angiotension II (Ang II)-treated cardiomyocytes and in hearts of Ang II-induced cardiac hypertrophic mice. In addition, SIRT3 overexpression protected myocytes from hypertrophy, whereas SIRT3 silencing exacerbated Ang II-induced cardiomyocyte hypertrophy. In particular, SIRT3-KO mice exhibited significant cardiac hypertrophy. Mechanistically, we identified NMNAT3 (nicotinamide mononucleotide adenylyltransferase 3), the rate-limiting enzyme for mitochondrial NAD biosynthesis, as a new target and binding partner of SIRT3. Specifically, SIRT3 physically interacts with and deacetylates NMNAT3, thereby enhancing the enzyme activity of NMNAT3 and contributing to SIRT3-mediated anti-hypertrophic effects. Moreover, NMNAT3 regulates the activity of SIRT3 via synthesis of mitochondria NAD. Taken together, these findings provide mechanistic insights into the negative regulatory role of SIRT3 in cardiac hypertrophy. Copyright © 2016. Published by Elsevier Inc.

  16. An Atypical SCF-like Ubiquitin Ligase Complex Promotes Wallerian Degeneration through Regulation of Axonal Nmnat2

    Directory of Open Access Journals (Sweden)

    Yuya Yamagishi

    2016-10-01

    Full Text Available Axon degeneration is a tightly regulated, self-destructive program that is a critical feature of many neurodegenerative diseases, but the molecular mechanisms regulating this program remain poorly understood. Here, we identify S-phase kinase-associated protein 1A (Skp1a, a core component of a Skp/Cullin/F-box (SCF-type E3 ubiquitin ligase complex, as a critical regulator of axon degeneration after injury in mammalian neurons. Depletion of Skp1a prolongs survival of injured axons in vitro and in the optic nerve in vivo. We demonstrate that Skp1a regulates the protein level of the nicotinamide adenine dinucleotide (NAD+ synthesizing enzyme nicotinamide mononucleotide adenylyltransferase 2 (Nmnat2 in axons. Loss of axonal Nmnat2 contributes to a local ATP deficit that triggers axon degeneration. Knockdown of Skp1a elevates basal levels of axonal Nmnat2, thereby delaying axon degeneration through prolonged maintenance of axonal ATP. Consistent with Skp1a functioning through regulation of Nmnat2, Skp1a knockdown fails to protect axons from Nmnat2 knockdown. These results illuminate the molecular mechanism underlying Skp1a-dependent axonal destruction.

  17. Biological Activities of the Essential Oil from Erigeron floribundus.

    Science.gov (United States)

    Petrelli, Riccardo; Orsomando, Giuseppe; Sorci, Leonardo; Maggi, Filippo; Ranjbarian, Farahnaz; Biapa Nya, Prosper C; Petrelli, Dezemona; Vitali, Luca A; Lupidi, Giulio; Quassinti, Luana; Bramucci, Massimo; Hofer, Anders; Cappellacci, Loredana

    2016-08-13

    Erigeron floribundus (Asteraceae) is an herbaceous plant widely used in Cameroonian traditional medicine to treat various diseases of microbial and non-microbial origin. In the present study, we evaluated the in vitro biological activities displayed by the essential oil obtained from the aerial parts of E. floribundus, namely the antioxidant, antimicrobial and antiproliferative activities. Moreover, we investigated the inhibitory effects of E. floribundus essential oil on nicotinate mononucleotide adenylyltransferase (NadD), a promising new target for developing novel antibiotics, and Trypanosoma brucei, the protozoan parasite responsible for Human African trypanosomiasis. The essential oil composition was dominated by spathulenol (12.2%), caryophyllene oxide (12.4%) and limonene (8.8%). The E. floribundus oil showed a good activity against Staphylococcus aureus (inhibition zone diameter, IZD of 14 mm, minimum inhibitory concentration, MIC of 512 µg/mL). Interestingly, it inhibited the NadD enzyme from S. aureus (IC50 of 98 µg/mL), with no effects on mammalian orthologue enzymes. In addition, T. brucei proliferation was inhibited with IC50 values of 33.5 µg/mL with the essential oil and 5.6 µg/mL with the active component limonene. The essential oil exhibited strong cytotoxicity on HCT 116 colon carcinoma cells with an IC50 value of 14.89 µg/mL, and remarkable ferric reducing antioxidant power (tocopherol-equivalent antioxidant capacity, TEAC = 411.9 μmol·TE/g).

  18. Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

    Science.gov (United States)

    Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

    2006-01-01

    Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

  19. Gallic Acid, Ellagic Acid and Pyrogallol Reaction with Metallic Iron

    Science.gov (United States)

    Jaén, J. A.; González, L.; Vargas, A.; Olave, G.

    2003-06-01

    The reaction between gallic acid, ellagic acid and pyrogallol with metallic iron was studied using infrared and Mössbauer spectroscopy. Most hydrolysable tannins with interesting anticorrosive or inhibition properties are structurally related to these compounds, thus they may be used as models for the study of hydrolysable tannins and related polyphenols. The interaction was followed up to 3 months. Results indicated two different behaviors. At polyphenol concentrations higher than 1% iron converts to sparingly soluble and amorphous ferric (and ferrous) polyphenolate complexes. At lower concentrations (0.1%), the hydrolysis reactions are dominant, resulting in the formation of oxyhydroxides, which can be further reduced to compounds like magnetite by the polyphenols.

  20. Kadcoccinic Acids A-J, Triterpene Acids from Kadsura coccinea.

    Science.gov (United States)

    Liang, Cheng-Qin; Shi, Yi-Ming; Wang, Wei-Guang; Hu, Zheng-Xi; Li, Yan; Zheng, Yong-Tang; Li, Xiao-Nian; Du, Xue; Pu, Jian-Xin; Xiao, Wei-Lie; Zhang, Hong-Bin; Sun, Han-Dong

    2015-08-28

    Eleven triterpene acids including 10 new compounds (kadcoccinic acids A-J, 1-10) were isolated from the stems of Kadsura coccinea. Except for 10, these compounds feature a rearranged lanostane skeleton with a 6/6/5/6 tetracyclic ring system, and compounds 1 and 2 are the first examples of 2,3-seco-6/6/5/6-fused tetracyclic triterpenoids. Their structures were established primarily by spectroscopic and spectrometric methods. Additionally, the absolute configuration of 3 was determined by single-crystal X-ray diffraction. Several of the compounds isolated were tested for their anti-HIV-1 and cytotoxic activities.

  1. Boronic acid-based autoligation of nucleic acids

    DEFF Research Database (Denmark)

    Barbeyron, R.; Vasseur, J.-J.; Smietana, M.;

    2013-01-01

    Abstract: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible...... boronate internucleosidic linkages. The DNA- or RNA-templated system comprises a 5′-ended boronic acid probe connecting a 3′-ended ribonucleosidic oligonucleotide partner. To explore the dominant factors that control the reversible linkage, we synthesized a series of 3′-end modified ribonucleotidic strands...

  2. Isothermal Amplification of Nucleic Acids.

    Science.gov (United States)

    Zhao, Yongxi; Chen, Feng; Li, Qian; Wang, Lihua; Fan, Chunhai

    2015-11-25

    Isothermal amplification of nucleic acids is a simple process that rapidly and efficiently accumulates nucleic acid sequences at constant temperature. Since the early 1990s, various isothermal amplification techniques have been developed as alternatives to polymerase chain reaction (PCR). These isothermal amplification methods have been used for biosensing targets such as DNA, RNA, cells, proteins, small molecules, and ions. The applications of these techniques for in situ or intracellular bioimaging and sequencing have been amply demonstrated. Amplicons produced by isothermal amplification methods have also been utilized to construct versatile nucleic acid nanomaterials for promising applications in biomedicine, bioimaging, and biosensing. The integration of isothermal amplification into microsystems or portable devices improves nucleic acid-based on-site assays and confers high sensitivity. Single-cell and single-molecule analyses have also been implemented based on integrated microfluidic systems. In this review, we provide a comprehensive overview of the isothermal amplification of nucleic acids encompassing work published in the past two decades. First, different isothermal amplification techniques are classified into three types based on reaction kinetics. Then, we summarize the applications of isothermal amplification in bioanalysis, diagnostics, nanotechnology, materials science, and device integration. Finally, several challenges and perspectives in the field are discussed.

  3. Reclamation of acid coal refuse

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, F.J.; Chong, S.K. (Southern Illinois Univ., Carbondale, IL (USA))

    1991-07-01

    Slurry (coal refuse), which contains pyritic materials, produces sulfuric acid when wetted and oxidized. The acidity, together with droughtiness and high surface temperatures, create a complex problem for revegetation. Four grasses, orchardgrass (Dactylis glomerata L.), redtop (Agrostis alba L.), reed canarygrass (Phalaris arundinacea L.) and tall fescue (Festuca arundinacea Shreb.), were planted on an acid slurry site at Captain Mine, Arch of Illinois Inc., Perry County, IL, USA, to evaluate the effects of soil amendments. Organic material from composted garbage (0, 112, 224 and 336 Mg/ha), limestone (0, 45, 90 and 135 Mg/ha) and a mixture of organic material and limestone (56/22.5, 112/45 and 168/67.5 Mg/ha) were incorporated into the slurry. All the grasses established succesfully and persisted best on treatments involving the addition of limestone. Tall fescue and reed canarygrass were the grasses best suited for the revegetation of the acid slurry impoundments. The grasses did not accumulate heavy metals to levels considered potentially toxic to livestock. The application of limestone with or without organic material appears to be a possible alternative method for revegetating acid slurry without the addition of a soil cover. 6 tabs., 12 refs.

  4. 21 CFR 582.5013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ascorbic acid. 582.5013 Section 582.5013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may...

  5. Microbial production of amino acids in Japan.

    Science.gov (United States)

    Kumagai, H

    2000-01-01

    The microbial biotechnology of amino acids production which was developed and industrialized in Japan have been summarized. The amino acids include L-glutamic acid, L-lysine, L-threonine, L-aspartic acid, L-alanine, L-cysteine, L-dihydroxyphenylalanine, D-p-hydroxyphenyl-glycine, and hydroxy-L-proline.

  6. 21 CFR 184.1097 - Tannic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Tannic acid. 184.1097 Section 184.1097 Food and... Substances Affirmed as GRAS § 184.1097 Tannic acid. (a) Tannic acid (CAS Reg. No. 1401-55-4), or hydrolyzable gallotannin, is a complex polyphenolic organic structure that yields gallic acid and either glucose or quinic...

  7. Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-03-01

    In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production.

  8. Anions in Nucleic Acid Crystallography.

    Science.gov (United States)

    D'Ascenzo, Luigi; Auffinger, Pascal

    2016-01-01

    Nucleic acid crystallization buffers contain a large variety of chemicals fitting specific needs. Among them, anions are often solely considered for pH-regulating purposes and as cationic co-salts while their ability to directly bind to nucleic acid structures is rarely taken into account. Here we review current knowledge related to the use of anions in crystallization buffers along with data on their biological prevalence. Chloride ions are frequently identified in crystal structures but display low cytosolic concentrations. Hence, they are thought to be distant from nucleic acid structures in the cell. Sulfate ions are also frequently identified in crystal structures but their localization in the cell remains elusive. Nevertheless, the characterization of the binding properties of these ions is essential for better interpreting the solvent structure in crystals and consequently, avoiding mislabeling of electron densities. Furthermore, understanding the binding properties of these anions should help to get clues related to their potential effects in crowded cellular environments.

  9. Toxicologic Study of Monochloroacetic Acid

    Institute of Scientific and Technical Information of China (English)

    Lu Bo; Zhan Ping

    2006-01-01

    @@ Monochloroacetic Acid (MCA) is a chlorinated analog of acetic acids. MCA and its sodium salt (SMCA) are widely used as a chemical intermediate (primarily in the manufacture of chlorophenoxy herbicides,carboxymethylcelluose, glycine and indigoid dyes).Moreover, MCA has been found as a common by-product of the chlorination of drinking water. Chloroacetates are ubiquitous in the environment, and MCA is the most abundant among chloroacetates. A background level of 0.1 - 1μg/L is expected to occur in precipitation[1]. Total world wide annual production of MCA reported was about 400 000 tons[2]. Many studies have showed that MCA not only caused acute or chronic damage to the skin , liver, kidney, heart, brain and other organs, but also caused acute death systemically under high concentration[2,3]. So this article will discuss the toxic effect of Monochloroacetic Acid in Toxicology.

  10. Fauna of an acid stream

    Energy Technology Data Exchange (ETDEWEB)

    Jewell, M.E.

    1922-01-01

    The hydrogen-ion concentration of the water of the big muddy river was found to vary between pH 5.8 and pH 6.8 to 7.2, the higher acidity occurring during the winter. The bottom fauna was characterized by the abundance of clams and shrimp, and by the absence of branchiate snails and ephemerid nymphs. Fish fry and fingerlings were found in large numbers during the summer in weakly acid water, pH 6.8. Observations on our acid streams, continued over a considerable period of time, would tell us much concerning the adaptability of various species to different hydrogen-ion concentrations and are greatly needed in the interpretation of experimental data.

  11. Be an acid rain detective

    Energy Technology Data Exchange (ETDEWEB)

    Atwill, L.

    1982-07-01

    Acid rain is discussed in a question and answer format. The article is aimed at educating sport fishermen on the subject, and also to encourage them to write their congressmen, senators, and the President about the acid rain problem. The article also announces the availability of an acid rain test kit available through the magazine, ''Sports Afield.'' The kit consists of pH-test paper that turns different shades of pink and blue according to the pH of the water tested. The color of the test paper is then compared to a color chart furnished in the kit and an approximate pH can be determined.

  12. Political economy of acid rain

    Energy Technology Data Exchange (ETDEWEB)

    Regens, J.L.

    Over the past decade, acid rain has been transformed from a relatively unnoticed area of scientific inquiry into a major environmental issue of regional, national, and international concern. What is acid rain, why has it acquired such relatively sudden political prominence, and what are the prospects for the adoption of policies addressing this issue. These questions illustrate how the regional cleavages inherent in transboundary air pollution problems have fractured the political coalitions which supported earlier environmental legislation. Understanding the basis for that transformation, which requires information from the natural and physical sciences as well as insights into the economics and politics of the acid rain issue, is central to developing an appreciation of the constraints on policymaking for air-quality management in the United States. 35 references.

  13. Tumor Acidity as Evolutionary Spite

    Directory of Open Access Journals (Sweden)

    Mohammed E. A. Shayoub

    2011-01-01

    Full Text Available Most cancer cells shift their metabolic pathway from a metabolism reflecting the Pasteur-effect into one reflecting the Warburg-effect. This shift creates an acidic microenvironment around the tumor and becomes the driving force for a positive carcinogenesis feedback loop. As a consequence of tumor acidity, the tumor microenvironment encourages a selection of certain cell phenotypes that are able to survive in this caustic environment to the detriment of other cell types. This selection can be described by a process which can be modeled upon spite: the tumor cells reduce their own fitness by making an acidic environment, but this reduces the fitness of their competitors to an even greater extent. Moreover, the environment is an important dimension that further drives this spite process. Thus, diminishing the selective environment most probably interferes with the spite process. Such interference has been recently utilized in cancer treatment.

  14. Tumor Acidity as Evolutionary Spite

    Energy Technology Data Exchange (ETDEWEB)

    Alfarouk, Khalid O., E-mail: khalid.alfarouk@act.sd [Department of Biotechnology, Africa City of Technology, Khartoum (Sudan); Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, Khartoum (Sudan); Muddathir, Abdel Khalig [Department of Pharmacognosy, Faculty of Pharmacy, University of Khartoum, Khartoum (Sudan); Shayoub, Mohammed E. A. [Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, Khartoum (Sudan)

    2011-01-20

    Most cancer cells shift their metabolic pathway from a metabolism reflecting the Pasteur-effect into one reflecting the Warburg-effect. This shift creates an acidic microenvironment around the tumor and becomes the driving force for a positive carcinogenesis feedback loop. As a consequence of tumor acidity, the tumor microenvironment encourages a selection of certain cell phenotypes that are able to survive in this caustic environment to the detriment of other cell types. This selection can be described by a process which can be modeled upon spite: the tumor cells reduce their own fitness by making an acidic environment, but this reduces the fitness of their competitors to an even greater extent. Moreover, the environment is an important dimension that further drives this spite process. Thus, diminishing the selective environment most probably interferes with the spite process. Such interference has been recently utilized in cancer treatment.

  15. Solubilities of Isophthalic Acid in Acetic Acid + Water Solvent Mixtures

    Institute of Scientific and Technical Information of China (English)

    CHENG Youwei; HUO Lei; LI Xi

    2013-01-01

    The solubilities of isophthalic acid (1) in binary acetic acid (2) + water (3) solvent mixtures were determined in a pressurized vessel.The temperature range was from 373.2 to 473.2K and the range of the mole fraction of acetic acid in the solvent mixtures was from x2 =0 to 1.A new method to measure the solubility was developed,which solved the problem of sampling at high temperature.The experimental results indicated that within the temperature range studied,the solubilities of isophthalic acid in all mixtures showed an increasing trend with increasing temperature.The experimental solubilities were correlated by the Buchowski equation,and the calculate results showed good agreement with the experimental solubilities.Furthermore,the mixed solvent systems were found to exhibit a maximum solubility effect on the solubility,which may be attributed to the intermolecular association between the solute and the solvent mixture.The maximum solubility effect was well modeled by the modified Wilson equation.

  16. Ghrelin and gastric acid secretion

    OpenAIRE

    Yakabi, Koji; Kawashima, Junichi; Kato, Shingo

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In t...

  17. CACODYLIC ACID (DMAV): METABOLISM AND ...

    Science.gov (United States)

    The cacodylic acid (DMAV) issue paper discusses the metabolism and pharmacokinetics of the various arsenical chemicals; evaluates the appropriate dataset to quantify the potential cancer risk to the organic arsenical herbicides; provides an evaluation of the mode of carcinogenic action (MOA) for DMAV including a consideration of the key events for bladder tumor formation in rats, other potential modes of action; and also considers the human relevance of the proposed animal MOA. As part of tolerance reassessment under the Food Quality Protection Act for the August 3, 2006 deadline, the hazard of cacodylic acid is being reassessed.

  18. Spherical agglomeration of acetylsalicylic acid

    Directory of Open Access Journals (Sweden)

    Polowczyk Izabela

    2016-01-01

    Full Text Available In this paper spherical agglomeration of acetylsalicylic acid was described. In the first step, the system of good and poor solvents as well as bridging liquid was selected. As a result of a preliminary study, ethyl alcohol, water and carbon tetrachloride were used as the good solvent, poor one, and bridging liquid, respectively. Then, the amount of acetylsalicylic acid and the ratio of the solvents as well as the volume of the bridging liquid were examined. In the last step, the agglomeration conditions, such as mixing intensity and time, were investigated. The spherical agglomerates obtained under optimum conditions could be subjected to a tableting process afterwards.

  19. Salicylic acid-independent plant defence pathways

    OpenAIRE

    Pieterse, C.M.J.; Loon, L. C. Van

    1999-01-01

    Salicylic acid is an important signalling molecule involved in both locally and systemically induced disease resistance responses. Recent advances in our understanding of plant defence signalling have revealed that plants employ a network of signal transduction pathways, some of which are independent of salicylic acid. Evidence is emerging that jasmonic acid and ethylene play key roles in these salicylic acid-independent pathways. Cross-talk between the salicylic acid-dependent and the salicy...

  20. General consideration on sialic acid chemistry.

    Science.gov (United States)

    Cao, Hongzhi; Chen, Xi

    2012-01-01

    Sialic acids, also known as neuraminic acids, are a family of negatively charged α-keto acids with a nine-carbon backbone. These unique sugars have been found at the termini of many glycan chains of vertebrate cell surface, which play pivotal roles in mediating or modulating a variety of physiological and pathological processes. This brief review covers general approaches for synthesizing sialic acid containing structures. Recently developed synthetic methods along with structural diversities and biological functions of sialic acid are discussed.

  1. 21 CFR 186.1316 - Formic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Formic acid. 186.1316 Section 186.1316 Food and... Substances Affirmed as GRAS § 186.1316 Formic acid. (a) Formic acid (CH2O2, CAS Reg. No. 64-18-6) is also referred to as methanoic acid or hydrogen carboxylic acid. It occurs naturally in some insects and is...

  2. Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid

    Directory of Open Access Journals (Sweden)

    Tareq Irshaidat

    2014-01-01

    Full Text Available On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput. 2012, 8, 2293 illustrated that beryllium ions are capable of significantly modulating (changing the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+, AlF2(1+, AlF2+, and Al3+ were investigated. Several aspects were addressed: natural bond orbitals, including second order perturbation analysis of intra-molecular charge delocalization and the natural population analysis atomic charges; molecular geometries; selected infrared stretching frequencies (C-N, C-O, and N-H, and selected ¹H-NMR chemical shifts. The data illustrate that this interaction can weaken the H-O bond and goes beyond strengthening the intra-molecular hydrogen bond (N...H-O to cause a spontaneous transfer of the proton to the nitrogen atom in five cases generating zwitterion structures. Many new features are observed. Most importantly, the zwitterion structures include a stabilizing hydrogen bond (N-H...O that varies in relative strength according to the Lewis acid. These findings explain the experimental observations of α-amino acids (for example: J. Am. Chem. Soc. 2001, 123, 3577 and are the first reported fundamental electronic structure characterization of β-amino acids in zwitterion form.

  3. Acid-functionalized polyolefin materials and their use in acid-promoted chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Oyola, Yatsandra; Tian, Chengcheng; Bauer, John Christopher; Dai, Sheng

    2016-06-07

    An acid-functionalized polyolefin material that can be used as an acid catalyst in a wide range of acid-promoted chemical reactions, wherein the acid-functionalized polyolefin material includes a polyolefin backbone on which acid groups are appended. Also described is a method for the preparation of the acid catalyst in which a precursor polyolefin is subjected to ionizing radiation (e.g., electron beam irradiation) of sufficient power and the irradiated precursor polyolefin reacted with at least one vinyl monomer having an acid group thereon. Further described is a method for conducting an acid-promoted chemical reaction, wherein an acid-reactive organic precursor is contacted in liquid form with a solid heterogeneous acid catalyst comprising a polyolefin backbone of at least 1 micron in one dimension and having carboxylic acid groups and either sulfonic acid or phosphoric acid groups appended thereto.

  4. Amino Acid Analyses of Acid Hydrolysates in Desert Varnish

    Science.gov (United States)

    Perry, Randall S.; Staley, James T.; Dworkin, Jason P.; Engel, Mike

    2001-01-01

    There has long been a debate as to whether rock varnish deposits are microbially mediated or are deposited by inorganic processes. Varnished rocks are found throughout the world primarily in arid and semi-arid regions. The varnish coats are typically up to 200 microns thick and are composed of clays and alternating layers enriched in manganese and iron oxides. The individual layers range in thickness from 1 micron to greater than 10 microns and may continue laterally for more than a 100 microns. Overlapping botryoidal structures are visible in thin section and scanning electron micrographs. The coatings also include small amounts of organic mater and detrital grains. Amino-acid hydrolysates offer a means of assessing the organic composition of rock varnish collected from the Sonoran Desert, near Phoenix, AZ. Chromatographic analyses of hydrolysates from powdered samples of rock varnish suggest that the interior of rock varnish is relatively enriched in amino acids and specifically in d-alanine and glutamic acid. Peptidoglycan (murein) is the main structural component of gram-positive bacterial cell walls. The d-enantiomer of alanine and glutamic acid are specific to peptidoglycan and are consequently an indicator for the presence of bacteria. D-alanine is also found in teichoic acid which is only found in gram-positive bacteria. Several researchers have cultured bacteria from the surface of rock varnish and most have been gram-positive, suggesting that gram-positive bacteria are intimately associated with varnish coatings and may play a role in the formation of varnish coatings.

  5. Kinetics of wet air oxidation of glyoxalic acid and oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Mahajani, V.V. (Univ. of Bombay (India). Dept. of Chemical Technology)

    1994-12-01

    Oxidation of lower molecular weight monobasic and dibasic acids such as formic acid, acetic acid, glyoxalic acid, and oxalic acid is often the rate-controlling step during wet air oxidation (WAO) of an aqueous waste stream exhibiting very high chemical oxygen demand (COD). The kinetics of WAO of glyoxalic acid and oxalic acid was studied in absence and presence of a cupric sulfate catalyst in the temperature range of 120--245 C and oxygen partial pressure of 0.345--1.380 MPa. The wet oxidation of oxalic acid was found to require more severe conditions as compared to glyoxalic acid. The reaction mechanism and kinetic model have been discussed.

  6. Citric Acid Passivation of Stainless Steel

    Science.gov (United States)

    Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

    2009-01-01

    Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

  7. Acid Rain: What It Is -- How You Can Help!

    Science.gov (United States)

    National Wildlife Federation, Washington, DC.

    This publication discusses the nature and consequences of acid precipitation (commonly called acid rain). Topic areas include: (1) the chemical nature of acid rain; (2) sources of acid rain; (3) geographic areas where acid rain is a problem; (4) effects of acid rain on lakes; (5) effect of acid rain on vegetation; (6) possible effects of acid rain…

  8. Acid Rain: What It Is -- How You Can Help!

    Science.gov (United States)

    National Wildlife Federation, Washington, DC.

    This publication discusses the nature and consequences of acid precipitation (commonly called acid rain). Topic areas include: (1) the chemical nature of acid rain; (2) sources of acid rain; (3) geographic areas where acid rain is a problem; (4) effects of acid rain on lakes; (5) effect of acid rain on vegetation; (6) possible effects of acid rain…

  9. Analysis of proteins responsive to acetic acid in Acetobacter: molecular mechanisms conferring acetic acid resistance in acetic acid bacteria.

    Science.gov (United States)

    Nakano, Shigeru; Fukaya, Masahiro

    2008-06-30

    Acetic acid bacteria are used for industrial vinegar production because of their remarkable ability to oxidize ethanol and high resistance to acetic acid. Although several molecular machineries responsible for acetic acid resistance in acetic acid bacteria have been reported, the entire mechanism that confers acetic acid resistance has not been completely understood. One of the promising methods to elucidate the entire mechanism is global analysis of proteins responsive to acetic acid by two-dimensional gel electrophoresis. Recently, two proteins whose production was greatly enhanced by acetic acid in Acetobacter aceti were identified to be aconitase and a putative ABC-transporter, respectively; furthermore, overexpression or disruption of the genes encoding these proteins affected acetic acid resistance in A. aceti, indicating that these proteins are involved in acetic acid resistance. Overexpression of each gene increased acetic acid resistance in Acetobacter, which resulted in an improvement in the productivity of acetic acid fermentation. Taken together, the results of the proteomic analysis and those of previous studies indicate that acetic acid resistance in acetic acid bacteria is conferred by several mechanisms. These findings also provide a clue to breed a strain having high resistance to acetic acid for vinegar fermentation.

  10. 5-Caffeoylquinic acid and caffeic acid orally administered suppresses P-selectin expression on mouse platelets

    Science.gov (United States)

    Caffeic acid and 5-caffeoylquinic acid are a naturally occurring phenolic acid and its ester found in human diets. In this paper, potential effects of caffeic acid and 5-caffeoylquinic acid found in coffee and other plant sources on platelet activation were studied via investigating P-selectin expre...

  11. Fatty acid profile of Albizia lebbeck and Albizia saman seed oils: Presence of coronaric acid

    Science.gov (United States)

    In this work, the fatty acid profiles of the seed oils of Albizia lebbeck and Albizia saman (Samanea saman) are reported. The oils were analyzed by GC, GC-MS, and NMR. The most prominent fatty acid in both oils is linoleic acid (30-40%), followed by palmitic acid and oleic acid for A. lebbeck and ol...

  12. 21 CFR 172.350 - Fumaric acid and salts of fumaric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Fumaric acid and salts of fumaric acid. 172.350... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.350 Fumaric acid and salts of fumaric acid. Fumaric acid and its calcium, ferrous, magnesium, potassium, and sodium salts may be safely used...

  13. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    NARCIS (Netherlands)

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  14. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    NARCIS (Netherlands)

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  15. Simultaneous liquid-chromatographic determination of urinary vanillylmandelic acid, homovanillic acid, and 5-hydroxyindoleacetic acid.

    Science.gov (United States)

    Gironi, A; Seghieri, G; Niccolai, M; Mammini, P

    1988-12-01

    We describe a liquid-chromatographic method for quantifying, simultaneously by a single procedure, vanillylmandelic acid (VMA), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in urine. After solvent extraction of acidified urine, the analytes were chromatographed on a C8 column, with use of a mobile phase of phosphate buffer (20 mmol/L, pH 4.0) and methanol with a variable gradient elution, and detected fluorometrically. We report the analytical recovery, sensitivity, precision, working linear range, and potential for interference from similar molecules or drugs. The results of such tests demonstrate that the proposed method is sensitive and reproducible. It is, furthermore, easy to perform, and thus is suitable for use in the clinical laboratory.

  16. Acid mine drainage - the chemistry

    CSIR Research Space (South Africa)

    Garland, Rebecca M

    2011-01-01

    Full Text Available the hydronium ion. pH is calculated using the concentration of the hydronium ion. A high concentration of these ions will make a solution acidic. In this reaction pathway, the reactions are occurring in water and thus produce an aqueous solution that has a...

  17. Getting folic acid nutrition right

    Science.gov (United States)

    The two articles in this issue of the journal provide some definitive answers to questions relating to folic acid exposure and folate nutritional status of the US population in the post-fortification era, and, by implication, pose other questions. Most convincingly, these reports, which are based la...

  18. Adipic Acid: Vigorous Import Growth

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Adipic acid is mainly used to manufacture nylon 6,6, plasticizers, grease, polyurethane etc. There are three major commercial production processes: cyclohexane process, cyclohexanol process, butadiene carbonylation process, and the air oxidation of cyclohexane process constitute 93% of the total.

  19. Boric Acid in Kjeldahl Analysis

    Science.gov (United States)

    Cruz, Gregorio

    2013-01-01

    The use of boric acid in the Kjeldahl determination of nitrogen is a variant of the original method widely applied in many laboratories all over the world. Its use is recommended by control organizations such as ISO, IDF, and EPA because it yields reliable and accurate results. However, the chemical principles the method is based on are not…

  20. Uric acid in multiple sclerosis

    NARCIS (Netherlands)

    Koch, M; De Keyser, J

    2006-01-01

    Peroxynitrite, a reactive oxidant formed by the reaction of nitric oxide with superoxide at sites of inflammation in multiple sclerosis (MS), is capable of damaging tissues and cells. Uric acid, a natural scavenger of peroxynitrite, reduces inflammatory demyelination in experimental allergic encepha

  1. 2-(3-Hydroxybenzylaminoacetic acid

    Directory of Open Access Journals (Sweden)

    Li-Hua Zhi

    2011-07-01

    Full Text Available There are two independent 2-(3-hydroxybenzylaminoacetic acid molecules, C9H11NO3, in the asymmetric unit of the title compound. The dihedral angle between the benzene rings of the two independent molecules is 58.12 (4°. The crystal packing is stablized by intermolecular O—H...O and N—H...O hydrogen bonds.

  2. Boric Acid in Kjeldahl Analysis

    Science.gov (United States)

    Cruz, Gregorio

    2013-01-01

    The use of boric acid in the Kjeldahl determination of nitrogen is a variant of the original method widely applied in many laboratories all over the world. Its use is recommended by control organizations such as ISO, IDF, and EPA because it yields reliable and accurate results. However, the chemical principles the method is based on are not…

  3. Engineering robust lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Bokhorst-van de Veen, van H.; Wels, M.; Kleerebezem, M.

    2011-01-01

    For centuries, lactic acid bacteria (LAB) have been industrially exploited as starter cultures in the fermentation of foods and feeds for their spoilage-preventing and flavor-enhancing characteristics. More recently, the health-promoting effects of LAB on the consumer have been widely acknowledged,

  4. Acid resistance of starch granules

    Energy Technology Data Exchange (ETDEWEB)

    Nara, S.; Sakakura, M.; Komiya, T.

    1983-08-01

    When potato starch was hydrolyzed to form Naegeli amylodextrin by 16% sulfuric acid at 30/sup 0/C, only the amorphous portion of the starch granules was deteriorated. The crystallinity of Naegeli amylodextrin showing the hydrolysis ratio of 0.22 was 1.28 times as large as that of original starch. The hydrolysis process at above 45/sup 0/C was given by two exponential equations. The value of acid resistance portion (C/sub 0/) at 30 and 38/sup 0/C was 100%, while the values at 45, 50 and 55/sup 0/C were 67, 38 and 18%, respectively. The high value of C/sub 0/ generally showed the high acid resistance in the various starches. Sweet potato and waxy rice starches were more easily hydrolysed than other starches, although they gave the relatively high value of C/sub 0/. Thus, it was slightly more difficult for low acid resistance portion of potato starch to be hydrolyzed than for that of other starches. Moreover, that of waxy rice was easily hydrolyzed.

  5. Combinatorics of aliphatic amino acids.

    Science.gov (United States)

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

    This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks.

  6. Liquid chromatography of organophosphorus acids

    NARCIS (Netherlands)

    Verweij, A.; Kientz, C.E.; Berg, J. van den

    1988-01-01

    The applicability of different liquid chromatographic systems such as ion-exchange, ion-exclusion, reversed phase and ion-pair partition was studied for the analysis of a number of simple structurally related organophosphorus acids which lack a chromophoric group. Preliminary experiments based on th

  7. Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Kessel, Kurt R.

    2015-01-01

    The Ground Systems Development and Operations (GSDO) Program at NASA John F. Kennedy Space Center (KSC), Florida, has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of NASA and the GSDO Program, the objective of this project is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys. This project is a direct follow-on to United Space Alliance (USA) work at KSC to optimize the parameters for the use of citric acid and verify effectiveness. This project will build off of the USA study to further evaluate citric acids effectiveness and suitability for corrosion protection of a number of stainless steels alloys used by NASA, the Department of Defense (DoD), and the European Space Agency (ESA).

  8. Effects of culture conditions on acetic acid production by bacteria ...

    African Journals Online (AJOL)

    SARAH

    2015-11-30

    Nov 30, 2015 ... Keywords: Acetic acid bacteria, acetic acid production, Cocoa fermentation, culture conditions. INTRODUCTION ... assessed by acid forming colony characterized by a ... production capacity to ethanol, lactic acid, acetic acid.

  9. Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids.

    Science.gov (United States)

    Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu

    2016-01-18

    Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3 -NaIO4 -mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues.

  10. Omega-3 Fatty Acids and Inflammatory Processes

    Directory of Open Access Journals (Sweden)

    Philip C. Calder

    2010-03-01

    Full Text Available Long chain fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or at least associated with, changes in fatty acid composition of cell membranes. Changes in these compositions can modify membrane fluidity, cell signaling leading to altered gene expression, and the pattern of lipid mediator production. Cell involved in the inflammatory response are typically rich in the n-6 fatty acid arachidonic acid, but the contents of arachidonic acid and of the n-3 fatty acids eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA can be altered through oral administration of EPA and DHA. Eicosanoids produced from arachidonic acid have roles in inflammation. EPA also gives rise to eicosanoids and these often have differing properties from those of arachidonic acid-derived eicosanoids. EPA and DHA give rise to newly discovered resolvins which are anti-inflammatory and inflammation resolving. Increased membrane content of EPA and DHA (and decreased arachidonic acid content results in a changed pattern of production of eicosanoids and resolvins. Changing the fatty acid composition of cells involved in the inflammatory response also affects production of peptide mediators of inflammation (adhesion molecules, cytokines etc.. Thus, the fatty acid composition of cells involved in the inflammatory response influences their function; the contents of arachidonic acid, EPA and DHA appear to be especially important. The anti-inflammatory effects of marine n-3 PUFAs suggest that they may be useful as therapeutic agents in disorders with an inflammatory component.

  11. Formation of volatile chemicals from thermal degradation of less volatile coffee components: quinic acid, caffeic acid, and chlorogenic acid.

    Science.gov (United States)

    Moon, Joon-Kwan; Shibamoto, Takayuki

    2010-05-12

    The less volatile constituents of coffee beans (quinic acid, caffeic acid, and chlorogenic acid) were roasted under a stream of nitrogen, air, or helium. The volatile degradation compounds formed were analyzed by gas chromatography and gas chromatography-mass spectrometry. Caffeic acid produced the greatest amount of total volatiles. Quinic acid and chlorogenic acid produced a greater number of volatiles under the nitrogen stream than under the air stream. These results suggest that the presence of oxygen does not play an important role in the formation of volatile compounds by the heat degradation of these chemicals. 2,5-Dimethylfuran formed in relatively large amounts (59.8-2231.0 microg/g) in the samples obtained from quinic acid and chlorogenic acid but was not found in the samples from caffeic acid. Furfuryl alcohol was found in the quinic acid (259.9 microg/g) and caffeic acid (174.4 microg/g) samples roasted under a nitrogen stream but not in the chlorogenic sample. The three acids used in the present study do not contain a nitrogen atom, yet nitrogen-containing heterocyclic compounds, pyridine, pyrrole, and pyrazines, were recovered. Phenol and its derivatives were identified in the largest quantities. The amounts of total phenols ranged from 60.6 microg/g (quinic acid under helium) to 89893.7 microg/g (caffeic acid under helium). It was proposed that phenol was formed mainly from quinic acid and that catechols were formed from caffeic acid. Formation of catechol from caffeic acid under anaerobic condition indicates that the reaction participating in catechol formation was not oxidative degradation.

  12. Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-09-01

    An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

  13. Eskimo plasma constituents, dihomo-gamma-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid inhibit the release of atherogenic mitogens.

    Science.gov (United States)

    Smith, D L; Willis, A L; Nguyen, N; Conner, D; Zahedi, S; Fulks, J

    1989-01-01

    Studies in man and laboratory animals suggest that omega 3 polyunsaturated fatty acid constituents of fish oils have antiatherosclerotic properties. We have studied the effects of several such polyunsaturated fatty acids for ability to modify the in vitro release of mitogens from human platelets. Such mitogens may produce the fibro-proliferative component of atherosclerotic plaques. Both 5,8,11,14,17-eicosapentaenoic acid (20:5 omega 3) and 4,7,10,13,16,19-docosahexaenoic acid (22:6 omega 3), major constituents of fish oils, inhibited adenosine diphosphate-induced aggregation of platelets and the accompanying release of mitogens. These effects are dose dependent. Linolenic acid (18:3 omega 3), the biosynthetic precursor of eicosapentaenoic acid, also inhibited platelet aggregation and mitogen release. Eicosapentaenoic acid also inhibited mitogen release from human monocyte-derived macrophages, which, in vivo, are an additional source of mitogens during atherogenesis. Potent inhibition of human platelet aggregation and mitogen release was also seen with dihomo-gamma-linolenic acid (8,11,14-eicosatrienoic acid 20:3 omega 6), whose levels are reportedly elevated in Eskimos subsisting on marine diets. We conclude that diets that elevate plasma and/or tissue levels of eicosapentaenoic acid, docosahexaenoic acid and dihomo-gamma-linolenic acid precursor gamma-linolenic acid (18:3 omega 6) may exert antiatherosclerotic effects by inhibiting the release of mitogens from platelets and other cells.

  14. Incorporation and distribution of dihomo-gamma-linolenic acid, arachidonic acid, and eicosapentaenoic acid in cultured human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Punnonen, K.; Puustinen, T.; Jansen, C.T.

    1986-02-01

    Human keratinocytes in culture were labelled with /sup 14/C-dihomo-gamma-linolenic acid, /sup 14/C-arachidonic acid or /sup 14/C-eicosapentaenoic acid. All three eicosanoid precursor fatty acids were effectively incorporated into the cells. In phospholipids most of the radioactivity was recovered, in neutral lipids a substantial amount, and as free unesterified fatty acids only a minor amount. Most of the radioactivity was found in phosphatidylethanolamine which was also the major phospholipid as measured by phosphorous assay. The incorporation of dihomo-gamma-linolenic acid and arachidonic acid into lipid subfractions was essentially similar. Eicosapentaenoic acid was, however, much less effectively incorporated into phosphatidylinositol + phosphatidylserine and, correspondingly, more effectively into triacylglycerols as compared to the two other precursor fatty acids. Once incorporated, the distribution of all three precursor fatty acids was relatively stable, and only minor amounts of fatty acids were released into the culture medium during short term culture (two days). Our study demonstrates that eicosanoid precursor fatty acids are avidly taken up by human keratinocytes and esterified into membrane lipids. The clinical implication of this finding is that dietary manipulations might be employed to cause changes in the fatty acid composition of keratinocytes.

  15. Synthesis of Stereoisomers of 3-Aminocyclohexanecarboxylic Acid and cis-3-Aminocyclohexene-5-carboxylic Acid

    Institute of Scientific and Technical Information of China (English)

    HU Yu; YU Sheng-Liang; YANG Yu-Jin; ZHU Jin; DENG Jin-Gen

    2006-01-01

    A practical synthesis of stereoisomers of 3-aminocyclohexanecarboxylic acid and cis-3-aminocyclohexene-5-carboxylic acid was achieved from cyclohexene-4-carboxylic acid via a key resolving approach with chiral 1-phenylethylamine.

  16. Biophysical properties of phenyl succinic acid derivatised hyaluronic acid

    DEFF Research Database (Denmark)

    Neves-Petersen, Maria Teresa; Klitgaard, Søren; Skovsen, Esben

    2010-01-01

    acid has been derivatised with the anhydride form of phenyl succinic acid (PheSA). The fluorescence of PheSA was efficiently quenched by the HA matrix. HA also acted as a singlet oxygen scavenger. Fluorescence lifetime(s) of PheSA in solution and when attached to the HA matrix has been monitored...... capacity of scavenging singlet oxygen and of quenching PheSA fluorescence. These studies revealed that HA-PheSA is a strong quencher of electronic excited state PheSA and acts as a scavenger of singlet oxygen, thus medical applications of this derivatised form of HA may protect tissues and organs...... with ps resolved streak camera technology. Structural and fluorescence properties changes induced on HA-PheSA due to the presence of singlet oxygen were monitored using static light scattering (SLS), steady state fluorescence and ps time resolved fluorescence studies. SLS studies provided insight...

  17. Chemical peeling - Glycolic acid versus trichloroacetic acid in melasma

    Directory of Open Access Journals (Sweden)

    Kalla G

    2001-01-01

    Full Text Available Melasma continues to be a therapeutic challenge. 100 patients of melasma not responding to conventional depigmenting agents were divided into 2 groups, one treated with 55 - 75% glycolic acid (68 patients and the other with 10-15% trichloroacetic acid (32 patients. Applications were made after every 15 days and response assessed clinically along with relapse or hyperpigmentation after 3 month follow up period. More than 75% improvement was seen in 30%, and 50-75% improvement in 24% patients. Response with TCA was more rapid as compared to GA. Chronic pigmentation responded more favourably to TCA. Relapse and hyperpigmentation was more-25% in TCA as compared to 5.9% GA. Sun exposure was the most important precipitating factor followed by pregnancy and drugs.

  18. [Biology of essential fatty acids (EFA)].

    Science.gov (United States)

    Dobryniewski, Jacek; Szajda, Sławomir Dariusz; Waszkiewicz, Napoleon; Zwierz, Krzysztof

    2007-01-01

    Essential Fatty Acids (EFA), are unsaturated fatty acids not produced by human being, but essential for proper functioning of the human body. To EFA-s belongs: linoleic acid (LA) (18:2,cis detla(9,12), omega6)--precursor o f gamma-linolenic acid (GLA), gamma-linolenic acid (GLA) (18:3,cisA6,9,12, )6) and alpha-linolenic acid (ALA)(18:3,cisdelta(9, 12, 15), omega3)--product of dehydrogenation of linoleic acid (LA). Most important EFA is gamma-linolenic acid (GLA)--18 carbons, one-carboxylic, non-branched fatty acid with 3 double cis-bonds (the last is situated by 6-th carbon from methylic end). The diet devoided of EFA leads to decreased growth, skin and kidney injury and infertility. Modern research of GLA and others EFA's is concerned mainly on therapeutic impact on the inflammatory process. The biogenic amines, cytokines, prostaglandins, tromboxanes and leukotrienes are the main inflammatory mediators. The last three are described with the common name eicosanoides (eico-twenty). Eicosanoides are synthesized from 20-carbon unsaturated fatty acids: dihomo-gamma-linoleic (DGLA) (20:3, cis delta(8,11,14), omega6), arachidonic acid (AA-20:4, cis delta(5,8,11,14), omega6), and eicosapentaenoic acid (EPA-20:5, cis delta(5,8,11,14,17, omega3). Derivatives of gamma and gamma-linolenic acids regulate the inflammatory process, through their opposed activity. PG2, leucotrien C4 and tromboxan A2 have the strongest proinflammatory action. Derivatives of alpha-linolenic acid 15-HETE and prostaglandin E1 (PGE1) have weak pro-inflammatory action, or even anti-inflammatory (PGE1), and additionally, they inhibit the transformation of arachidonic acid (AA) to leukotriens. delta6-desaturase (transformes linolenic acid into gamma-linolenic acid by making additional double bond) is the slowest step of the fatty acid metabolism. It's activity is impaired by many physiological and pathologic factors and leads to gamma-linolenic acid (GLA) deficiency. The gamma-linolenic acid

  19. Endocrine and paracrine role of bile acids

    Institute of Scientific and Technical Information of China (English)

    Verena Keitel; Ralf Kubitz; Dieter H(a)ussinger

    2008-01-01

    Bile acids are not only important for the absorption of dietary lipids and fat soluble vitamins but are signalling molecules with diverse endocrine and paracrine functions.Bile acids regulate bile acid,lipid and glucose metabolism and modulate temperature and energy homeostasis.Furthermore,bile acids can not only promote cell proliferation and liver regeneration but can also induce programmed cell death.Bile acid functions are mediated through different pathways which comprise the activation of nuclear hormone receptors,of intracellular kinases and of the plasma membranebound,G-protein coupled bile acid receptor TGR5/Gpbar-1.

  20. Accidental intoxication with hydrochloric acid and hydrofluoric acid mixture

    Directory of Open Access Journals (Sweden)

    Anna Smędra-Kaźmirska

    2014-08-01

    Full Text Available The paper describes a fatal case of accidental ingestion of a mixture of hydrochloric acid and hydrofluoric acid. The man was admitted to hospital, where appropriate treatment, adequate to his condition, was instituted. Numerous ventricular fibrillation episodes, for which the patient was defibrillated repeatedly, were observed during the period of hospitalization. The patient was in a critical condition, with progressive symptoms of hypovolemic shock and multiorgan failure. On the next day after admission, signs of electromechanical dissociation progressing to asystole were noted. The instituted resuscitation procedure proved ineffective and the patient died. Autopsy revealed brownish discoloration of the esophageal, gastric, and small intestinal mucous membranes. Numerous ulcerations without signs of perforation were found both in the esophagus and in the stomach. The mucous membrane of the small intestine demonstrated focal rubefactions, whereas no focal lesions of the large intestinal mucosa were seen. Microscopic investigation of the biopsy specimens collected from the stomach, duodenum and small intestine revealed mucous membrane necrosis foci, reaching the deeper layers of the wall of these organs. The mucous membrane of the large intestine was congested. Bioptates obtained from the lungs indicated the presence of hemorrhagic infarcts and focal extravasations. Poisoning with the aforementioned acids with consequent necrosis of the esophageal, gastric, duodenal and small intestinal walls with hemorrhages to the gastrointestinal tract, as well as extravasations and hemorrhagic infarcts in the lungs was considered to be the cause of death.

  1. Accidental intoxication with hydrochloric acid and hydrofluoric acid mixture.

    Science.gov (United States)

    Smędra-Kaźmirska, A; Kędzierski, M; Barzdo, M; Jurczyk, Ap; Szram, S; Berent, J

    2014-01-01

    The paper describes a fatal case of accidental ingestion of a mixture of hydrochloric acid and hydrofluoric acid. The man was admitted to hospital, where appropriate treatment, adequate to his condition, was instituted. Numerous ventricular fibrillation episodes, for which the patient was defibrillated repeatedly, were observed during the period of hospitalization. The patient was in a critical condition, with progressive symptoms of hypovolemic shock and multiorgan failure. On the next day after admission, signs of electromechanical dissociation progressing to asystole were noted. The instituted resuscitation procedure proved ineffective and the patient died. Autopsy revealed brownish discoloration of the esophageal, gastric, and small intestinal mucous membranes. Numerous ulcerations without signs of perforation were found both in the esophagus and in the stomach. The mucous membrane of the small intestine demonstrated focal rubefactions, whereas no focal lesions of the large intestinal mucosa were seen. Microscopic investigation of the biopsy specimens collected from the stomach, duodenum and small intestine revealed mucous membrane necrosis foci, reaching the deeper layers of the wall of these organs. The mucous membrane of the large intestine was congested. Bioptates obtained from the lungs indicated the presence of hemorrhagic infarcts and focal extravasations. Poisoning with the aforementioned acids with consequent necrosis of the esophageal, gastric, duodenal and small intestinal walls with hemorrhages to the gastrointestinal tract, as well as extravasations and hemorrhagic infarcts in the lungs was considered to be the cause of death.

  2. Ursodeoxycholic acid in the Ursidae: biliary bile acids of bears, pandas, and related carnivores.

    Science.gov (United States)

    Hagey, L R; Crombie, D L; Espinosa, E; Carey, M C; Igimi, H; Hofmann, A F

    1993-11-01

    The biliary bile acid composition of gallbladder bile obtained from six species of bears (Ursidae), the Giant panda, the Red panda, and 11 related carnivores were determined by reversed phase liquid chromatography and gas chromatography-mass spectrometry. Bile acids were conjugated solely with taurine (in N-acyl linkage) in all species. Ursodeoxycholic acid (3 alpha, 7 beta-dihydroxy-5 beta-cholan-24-oic acid) was present in all Ursidae, averaging 1-39% of biliary bile acids depending on the species; it was not detected or present as a trace constituent (bears, and its proportion averaged 34% (range 0-62%). Ursodeoxycholic acid averaged 17% of biliary bile acids in the Polar bear (n = 4) and 18% in the Brown bear (n = 6). Lower proportions (1-8%) were present in the Sun bear (n = 2), Ceylon Sloth bear (n = 1), and the Spectacled bear (n = 1). Bile of all species contained taurine-conjugated chenodeoxycholic acid and cholic acid. In some related carnivores, deoxycholic acid, the 7-dehydroxylation product of cholic acid, was also present. To determine whether the 7 beta hydroxy group of ursodeoxycholic acid was formed by hepatic or bacterial enzymes, bile acids were determined in hepatic bile obtained from bears with chronic biliary fistulae. Fistula bile samples contained ursodeoxycholic acid, chenodeoxycholic acid, and a trace amount of cholic acid, all as taurine conjugates, indicating that ursodeoxycholic acid is a primary bile acid formed in the liver in Ursidae.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Interference effects from coexisting fatty acids on elaidic acid separation by fractionating crystallization: A model study

    DEFF Research Database (Denmark)

    Jala, Ram Chandra Reddy; Guo, Zheng; Bjerring, Thomas;

    2010-01-01

    A multi-stage temperature-programmed fractionating crystallization process was carried out to examine the effects of the presence of stearic acid (SA), oleic acid (OA), and linoleic acid (LA) on the separation of elaidic acid (EA). The results showed that the efficiency of fractionating crystalli......A multi-stage temperature-programmed fractionating crystallization process was carried out to examine the effects of the presence of stearic acid (SA), oleic acid (OA), and linoleic acid (LA) on the separation of elaidic acid (EA). The results showed that the efficiency of fractionating...

  4. The effects of borate minerals on the synthesis of nucleic acid bases, amino acids and biogenic carboxylic acids from formamide.

    Science.gov (United States)

    Saladino, Raffaele; Barontini, Maurizio; Cossetti, Cristina; Di Mauro, Ernesto; Crestini, Claudia

    2011-08-01

    The thermal condensation of formamide in the presence of mineral borates is reported. The products afforded are precursors of nucleic acids, amino acids derivatives and carboxylic acids. The efficiency and the selectivity of the reaction was studied in relation to the elemental composition of the 18 minerals analyzed. The possibility of synthesizing at the same time building blocks of both genetic and metabolic apparatuses, along with the production of amino acids, highlights the interest of the formamide/borate system in prebiotic chemistry.

  5. Linoleic acid: between doubts and certainties.

    Science.gov (United States)

    Choque, Benjamin; Catheline, Daniel; Rioux, Vincent; Legrand, Philippe

    2014-01-01

    Linoleic acid is the most abundant polyunsaturated fatty acid in human nutrition and represents about 14 g per day in the US diet. Following the discovery of its essential functions in animals and humans in the early 1920's, studies are currently questioning the real requirement of linoleic acid. It seems now overestimated and creates controversy: how much linoleic acid should be consumed in a healthy diet? Beyond the necessity to redefine the dietary requirement of linoleic acid, many questions concerning the consequences of its excessive consumption on human health arise. Linoleic acid is a direct precursor of the bioactive oxidized linoleic acid metabolites. It is also a precursor of arachidonic acid, which produces pro-inflammatory eicosanoids and endocannabinoids. A majority of the studies on linoleic acid and its derivatives show a direct/indirect link with inflammation and metabolic diseases. Many authors claim that a high linoleic acid intake may promote inflammation in humans. This review tries to (i) highlight the importance of reconsidering the actual requirement of linoleic acid (ii) point out the lack of knowledge between dietary levels of linoleic acid and the molecular mechanisms explaining its physiological roles (iii) demonstrate the relevance of carrying out further human studies on the single variable linoleic acid.

  6. Effect of supplementation of arachidonic acid (AA) or a combination of AA plus docosahexaenoic acid on breastmilk fatty acid composition

    NARCIS (Netherlands)

    Smit, EN; Koopmann, M; Boersma, ER; Muskiet, FAJ

    2000-01-01

    We investigated whether supplementation with arachidonic acid (20:4 omega 6; AA), ora combination of AA and docosahexaenoic acid (22:6 omega 3; DHA) would affect human milk polyunsaturated fatty acid (PUFA) composition. Ten women were daily supplemented with 300 mg AA, eight with 300 mg AA, 110 mg e

  7. Prenatal long-chain polyunsaturated fatty acid status : the importance of a balanced intake of docosahexaenoic acid and arachidonic acid

    NARCIS (Netherlands)

    Hadders-Algra, Mijna

    2008-01-01

    This review addresses the effect of prenatal long-chain polyunsaturated fatty acid (LCPUFA) status on neuro-developmental outcome. It focuses on the major LPCUFA doxosahexaenoic acid (DNA; 22:6 omega 3) and arachidonic acid (AA; 20:4 omega 6). Due to enzymatic competition high DHA intake results in

  8. Lower fetal status of docosahexaenoic acid, arachidonic acid and essential fatty acids is associated with less favorable neonatal neurological condition

    NARCIS (Netherlands)

    Dijck-Brouwer, DAJ; Hadders-Algra, M; Bouwstra, H; Decsi, T; Boehm, G; Martini, IA; Boersma, ER; Muskiet, FAJ

    2005-01-01

    Long-chain polyunsaturated fatty acids, notably arachidonic (AA) and docosahexaenoic (DHA) acids are abundant in brain and may be conditionally essential in fetal life. We investigated umbilical artery (UA) and vein (UV) fatty acid compositions and early neonatal neurological condition in 317 term i

  9. Prenatal long-chain polyunsaturated fatty acid status : the importance of a balanced intake of docosahexaenoic acid and arachidonic acid

    NARCIS (Netherlands)

    Hadders-Algra, Mijna

    2008-01-01

    This review addresses the effect of prenatal long-chain polyunsaturated fatty acid (LCPUFA) status on neuro-developmental outcome. It focuses on the major LPCUFA doxosahexaenoic acid (DNA; 22:6 omega 3) and arachidonic acid (AA; 20:4 omega 6). Due to enzymatic competition high DHA intake results in

  10. Effect of supplementation of arachidonic acid (AA) or a combination of AA plus docosahexaenoic acid on breastmilk fatty acid composition

    NARCIS (Netherlands)

    Smit, EN; Koopmann, M; Boersma, ER; Muskiet, FAJ

    We investigated whether supplementation with arachidonic acid (20:4 omega 6; AA), ora combination of AA and docosahexaenoic acid (22:6 omega 3; DHA) would affect human milk polyunsaturated fatty acid (PUFA) composition. Ten women were daily supplemented with 300 mg AA, eight with 300 mg AA, 110 mg

  11. Polyunsaturated fatty acids and epilepsy.

    Science.gov (United States)

    Taha, Ameer Y; Burnham, W McIntyre; Auvin, Stéphane

    2010-08-01

    Omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) are dietary fatty acids that are involved in a myriad of physiologic processes in the brain. There is some evidence suggesting that PUFAs-and particularly omega-3 PUFAs-may have anticonvulsant effects, both in humans and in animals. In the present review, we assess the evidence related to the antiseizure properties of the n-3 PUFAs, discuss their possible mechanism(s) of action, and make recommendations for future clinical trials. In general, the available data from cell cultures and whole animal studies support the idea that the n-3 PUFAs have antiseizure properties. Future clinical trials involving the n-3 PUFAs should involve higher doses and longer periods of administration in order to definitively assess their possible antiseizure effects.

  12. Ursodeoxycholic acid and superoxide anion

    Institute of Scientific and Technical Information of China (English)

    Predrag Ljubuncic; Omar Abu-Salach; Arieh Bomzon

    2005-01-01

    AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.

  13. Prostatic acid phosphatase by radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Lindholm, G.R.; Stirton, M.S.; Liedtke, R.J.; Batjer, J.D.

    1980-11-07

    Prostatic acid phosphatase values in 98 patients with prostatic carcinoma were measured by a commmercial radioimmunoassay (RIA) and by enzymatic assay. Forty-three carcinomas were staged by rigorous pathological criteria. Patients (N = 129) with benign prostatic hyperplasia were the control group. At 94% specificity, sensitivities of the RIA vs the enzymatic assay for clinically staged patients were as follows: stage A, 22% vs 6%; B, 29% vs 10%; C, 52% vs 38%; and D, 87% vs 80%. However, none of the seven patients with pathological stage A and B disease had a positive test result, and we suggest that variability in staging criteria accounts for the discrepant sensitivity claims reported. Prostatic acid phosphatase RIA should not be used for screening but as an adjunct for staging known prostatic carcinoma.

  14. Nucleic acid based logical systems.

    Science.gov (United States)

    Han, Da; Kang, Huaizhi; Zhang, Tao; Wu, Cuichen; Zhou, Cuisong; You, Mingxu; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

    2014-05-12

    Researchers increasingly visualize a significant role for artificial biochemical logical systems in biological engineering, much like digital logic circuits in electrical engineering. Those logical systems could be utilized as a type of servomechanism to control nanodevices in vitro, monitor chemical reactions in situ, or regulate gene expression in vivo. Nucleic acids (NA), as carriers of genetic information with well-regulated and predictable structures, are promising materials for the design and engineering of biochemical circuits. A number of logical devices based on nucleic acids (NA) have been designed to handle various processes for technological or biotechnological purposes. This article focuses on the most recent and important developments in NA-based logical devices and their evolution from in vitro, through cellular, even towards in vivo biological applications.

  15. Palmitic Acid and Health: Introduction.

    Science.gov (United States)

    Agostoni, Carlo; Moreno, Luis; Shamir, Raanan

    2016-09-09

    Interest in the dietary role and metabolic effect of saturated fatty acids has been recently renewed on the basis of epidemiologic observations and economical approach to health and well-being. Saturated fats may favorably increase blood HDL-Cholesterol levels without significant changes of the total cholesterol/HDL-Cholesterol ratio. Also, the negative effect of saturated fat on cardiovascular diseases risk has recently been challenged. Palmitic acid, among all, may have special structural and functional roles in utero and in infancy, and indeed is it is being delivered in a unique form in human milk. Future research should include objective cost-benefit analyses when disentangling the role of saturated fats in dietary recommendations.

  16. Signalling properties of lysophosphatidic acid.

    Science.gov (United States)

    Durieux, M E; Lynch, K R

    1993-06-01

    Lysophosphatidic acid (LPA) is the simplest natural phospholipid, primarily known as a membrane component and metabolic intermediate. However, a remarkable variety of biological effects of this compound have come to light, seemingly pointing to an additional role for LPA as a signalling molecule. In this review, Marcel Durieux and Kevin Lynch integrate the recent information that indicates that LPA could be an intercellular messenger, possibly acting through a G protein-coupled receptor, and with a role in cell growth and motility.

  17. Diagnostic relevance of uric acid

    OpenAIRE

    2015-01-01

    Uric acid, the final product of purine metabolism, is one of the most recognized biological markers, a catalyzed reaction by xantina oxidoreductasa (XOR). This bifunctional enzyme in its dehydrogenated shape (XDH), produces AU, and nicotidamide adenine dinucleotide and in oxidase (XO), AU and Superoxide (O2•-). Hyperuricemia (HAU) is an indicator of over-regulation of XO activity, a powerful system producer of species of reactive oxygen (ROS), in human physiology. Accumulation of these radica...

  18. Nucleic acid detection using MNAzymes.

    Science.gov (United States)

    Gerasimova, Yulia V; Kolpashchikov, Dmitry M

    2010-02-26

    Deoxyribozymes are promising biotechnological tools. In a recent JACS article, Mokany et al. reported on the design of multi-component deoxyribozyme (MNAzyme) sensors based on 10-23 and 8-17 DNA enzymes. The sensors can detect down to 5 pM of a specific nucleic acid. The versatility of MNAzyme platform allows the design of catalytic cascades for signal amplification. This work is a step forward to PCR-free molecular diagnostics.

  19. Histidine-Containing Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2000-01-01

    Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics.......Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics....

  20. Succinic acid: technology development and commercialization

    Science.gov (United States)

    Succinic acid is a precursor of many important, large volume industrial chemicals and consumer products. It was common knowledge that many ruminant microorganisms accumulated succinic acid under anaerobic conditions. However, it was not until the discovery of Anaerobiospirillum succiniciproducens at...

  1. 21 CFR 184.1007 - Aconitic acid.

    Science.gov (United States)

    2010-04-01

    ... salt from cane sugar or molasses. It may be synthesized by sulfuric acid dehydration of citric acid... availability of this incorporation by reference is given in paragraph (b)(1) of this section. (7) Residue...

  2. Biobased synthesis of acrylonitrile from glutamic acid

    NARCIS (Netherlands)

    Notre, le J.E.L.; Scott, E.L.; Franssen, M.C.R.; Sanders, J.P.M.

    2011-01-01

    Glutamic acid was transformed into acrylonitrile in a two step procedure involving an oxidative decarboxylation in water to 3-cyanopropanoic acid followed by a decarbonylation-elimination reaction using a palladium catalyst

  3. Chronic boric acid poisoning in infants.

    OpenAIRE

    O`Sullivan, K.; Taylor, M.

    1983-01-01

    We report 7 infants suffering from seizures induced by chronic boric acid ingestion. The boric acid was given by dipping a soother in a proprietary borax and honey mixture. The babies have remained well since the mixture was withheld.

  4. Chronic boric acid poisoning in infants.

    Science.gov (United States)

    O'Sullivan, K; Taylor, M

    1983-09-01

    We report 7 infants suffering from seizures induced by chronic boric acid ingestion. The boric acid was given by dipping a soother in a proprietary borax and honey mixture. The babies have remained well since the mixture was withheld.

  5. Self-breaking retarded acid emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Scherubel, G.A.

    1979-02-20

    A subterranean formation is acidized with an acid-in-oil emulsion consisting of an aqueous acidizing solution, an oil, an alkyl C/sub 8/ to C/sub 18/ primary fatty amine, and at least one diethanolamide of at least one C/sub 8/ to C/sub 18/ fatty acid. The present invention is an improved acid-in-oil acidizing emulsion, and acidizing method such as an emulsion, the emulsion being of the type containing an effective amount of at least one C/sub 8/ to C/sub 18/ primary amine as a cationic surfactant to increase the normal reaction. The diethanolamine is a nonionic surfactant which causes the emulsion to break as the acidizing capacity of the emulsion becomes substantially depleted, i.e., spent, on the formation. 41 claims.

  6. Glutamic acid as anticancer agent: An overview

    National Research Council Canada - National Science Library

    Dutta, Satyajit; Ray, Supratim; Nagarajan, K

    2013-01-01

    The objective of the article is to highlight various roles of glutamic acid like endogenic anticancer agent, conjugates to anticancer agents, and derivatives of glutamic acid as possible anticancer agents...

  7. Biobased synthesis of acrylonitrile from glutamic acid

    NARCIS (Netherlands)

    Notre, le J.E.L.; Scott, E.L.; Franssen, M.C.R.; Sanders, J.P.M.

    2011-01-01

    Glutamic acid was transformed into acrylonitrile in a two step procedure involving an oxidative decarboxylation in water to 3-cyanopropanoic acid followed by a decarbonylation-elimination reaction using a palladium catalyst

  8. Bile acids for primary sclerosing cholangitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Gluud, C

    2003-01-01

    Bile acids have been used for treating primary sclerosing cholangitis, but their beneficial and harmful effects remain unclear.......Bile acids have been used for treating primary sclerosing cholangitis, but their beneficial and harmful effects remain unclear....

  9. Lactic acid fermentation-aided biomass conversion

    Energy Technology Data Exchange (ETDEWEB)

    Martin, A.M. [Memorial Univ. of Newfoundland, St. John`s, NF (Canada). Dept. of Biochemistry

    1996-09-01

    The preservation of fisheries biomass by lactic acid fermentation is discussed. This method is favourably compared to acid ensiling and fish meal production in terms of safety considerations, energy requirements, simplicity of process and product quality. (Author)

  10. Lactic Acid Bacteria in Health and Disease

    African Journals Online (AJOL)

    reports demonstrating the health promoting effects of ... therapy. In 1908, élie Metchinkoff, proposed that the acid-producing organisms (lactic acid bacteria) ... Phage resistance aids in .... In a study conducted [29] in children aged 3 it was found.

  11. Acid loading test (pH)

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003615.htm Acid loading test (pH) To use the sharing features on this page, please enable JavaScript. The acid loading test (pH) measures the ability of the ...

  12. Acid Rain Program Opt-in Factsheet

    Science.gov (United States)

    Learn about the Opt-in Program, which allows sources not required to participate in the Acid Rain Program the opportunity to enter the program on a voluntary basis and receive Acid Rain Program allowances.

  13. Dilute Acid and Autohydrolysis Pretreatment

    Science.gov (United States)

    Yang, Bin; Wyman, Charles E.

    Exposure of cellulosic biomass to temperatures of about 120-210°C can remove most of the hemicellulose and produce cellulose-rich solids from which high glucose yields are possible with cellulase enzymes. Furthermore, the use of dilute sulfuric acid in this pretreatment operation can increase recovery of hemicellulose sugars substantially to about 85-95% of the maximum possible versus only about 65% if no acid is employed. The use of small-diameter tubes makes it possible to employ high solids concentrations similar to those preferred for commercial operations, with rapid heat-up, good temperature control, and accurate closure of material balances. Mixed reactors can be employed to pretreat larger amounts of biomass than possible in such small-diameter tubes, but solids concentrations are limited to about 15% or less to provide uniform temperatures. Pretreatment of large amounts of biomass at high solids concentrations is best carried out using direct steam injection and rapid pressure release, but closure of material balances in such “steam gun” devices is more difficult. Although flow of water alone or containing dilute acid is not practical commercially, such flow-through configurations provide valuable insight into biomass deconstruction kinetics not possible in the batch tubes, mixed reactors, or steam gun systems.

  14. Acupuncture and gastric acid studies.

    Science.gov (United States)

    Sodipo, J O; Falaiye, J M

    1979-01-01

    The effects of therapeutic acupuncture on gastric acid secretion on pain relief in chronic duodenal ulcer patients were studied. Ten adult Nigerian patients with clinical, endoscopic as well as radiological evidence of duodenal ulcer constituted the "Ulcer Group." Four other patients who gave history of dyspepsia formed the "Dyspeptic Group." Pentagastrin stimulation test was performed on all subjects pre- and post-acupuncture therapy. The classical Chinese acupuncture loci were employed. The mean Basal Acid Output (BAO) in the duodenal ulcer group was markedly reduced from 4.04 +/- 1.01 mMols/hour to 1.05 +/- 2.5 mMols/hour. The mean Maximal Acid Output (MAO) was lowered from 34.72 +/- 13.81 mMols/hour to 15.34 +/- 4.01 mMols/hour. The difference was statistically significant (P less than 0.001). It is more probable, therefore, that the relief of pain is attributable to the therapeutic inhibition of gastric hyperacidity in our patients. Thus, though pain relief has been previously demonstrated in response to acupuncture, the results of this investigation have gone further to show that acupunture achieves symptomatic relief through therapeutic gastric depression in duodenal ulcer patients.

  15. Incorporation of conjugated linoleic acid (CLA and α-linolenic acid (LNA in pacu fillets

    Directory of Open Access Journals (Sweden)

    Deoclécio José Barilli

    2014-03-01

    Full Text Available The objective of this study was to evaluate the incorporation of conjugated linoleic acid and α-linolenic acid in fillets of pacu fish raised in net cages and fed diets enriched with these acids. The fish were fed for 49 days, and at the end of this period the fatty acid content in the fillets was determined by gas chromatography. Concentrations of α-linolenic acid, eicosapentaenoic acid, and the total omega-3 (n-3 fatty acid in the fillets increased, improving the n-6/n-3 ratio. In addition, the incorporation of conjugated linoleic acid in the fish fillets proved well established. This study showed that the use of diets enriched with conjugated linoleic acid and α-linolenic acid results in the incorporation of these acids in the of pacu fish fillets, improving their nutritional quality.

  16. Capture and release of acid-gasses with acid-gas binding organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Heldebrant, David J; Yonker, Clement R; Koech, Phillip K

    2015-03-17

    A system and method for acid-gas capture wherein organic acid-gas capture materials form hetero-atom analogs of alkyl-carbonate when contacted with an acid gas. These organic-acid gas capture materials include combinations of a weak acid and a base, or zwitterionic liquids. This invention allows for reversible acid-gas binding to these organic binding materials thus allowing for the capture and release of one or more acid gases. These acid-gas binding organic compounds can be regenerated to release the captured acid gasses and enable these organic acid-gas binding materials to be reused. This enables transport of the liquid capture compounds and the release of the acid gases from the organic liquid with significant energy savings compared to current aqueous systems.

  17. Profile of Fatty Acids, Amino Acids, Carotenoid Total, and α-Tocopherol from Flying Fish Eggs

    Directory of Open Access Journals (Sweden)

    Aulia Azka

    2015-12-01

    Full Text Available Flying fish are found in waters of eastern Indonesia, which until now is still limited information about nutritional content. The purpose of this research was determine the composition of fatty acids, amino acids, total carotenoids, α-tocopherol flying fish eggs (Hyrundicthys sp.. The composition of fatty acid was measured by gas chromatography (GC, while amino acids, total carotenoids, α-tocopherol was measured by High performanced Liquid Chromatography (HPLC. Egg contained 22 fatty acids such as saturated fatty acid 29.71%, monounsaturated fatty acid 7.86%, and polysaturated fatty acid 13.64%. The result showed that eggs flying fish contained 17 amino acids, such as essential amino acid 14.96% and non-essential amino acids 20.27%. Eggs contained a total carotenoid of 245.37 ppm. α-tocopherol content of flying fish eggs by 1.06 ppm.

  18. The beneficial biological properties of salicylic acid

    OpenAIRE

    Randjelović Pavle; Veljković Slavimir; Stojiljković Nenad; Sokolović Dušan; Ilić Ivan; Laketić Darko; Randjelović Dušica; Randjelović Nebojša

    2015-01-01

    Salicylic acid is a phytochemical with beneficial effects on human well-being. Salicylic acid is a phenolic compound and is present in various plants where it has a vital role in protection against pathogenic agents. Natural sources include fruits, vegetables and spices. The most famous and defined effect of salicylic acid is prostaglandin synthesis inhibition. Salicylic acid has antiinflammatory effects through suppression of transcription of genes for cyclooxygenase. Most of the pharmacolog...

  19. Enhancement of colposcopic image by sulphosalicylic acid.

    Directory of Open Access Journals (Sweden)

    Khilnani P

    1993-01-01

    Full Text Available Acetic acid is used conventionally for enhancement of the colposcopic image. We used sulphosalicylic acid instead of acetic acid in 50 normal cases. The normal appearance was enhanced in all cases. The image was also enhanced in 70% cases of cervical intraepithelial neoplasia and 90% cases of cervical condyloma accuminata. The image was not inferior to that with acetic acid in any of the cases.

  20. Production of high molecular weight polylactic acid

    Science.gov (United States)

    Bonsignore, Patrick V.

    1995-01-01

    A degradable high molecular weight poly(lactic acid). A poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  1. Amino and fatty acids in carbonaceous meteorites

    Science.gov (United States)

    Kvenvolden, K. A.

    1974-01-01

    Analyses of two carbonaceous meteorites have provided much of the latest evidence which seems to support Oparin's theory on the origin of life. The meteorites involved are the Murray meteorite, which fell in 1950, and the Murchison meteorite, which fell in 1969. The amino acids in the two meteorites are similar in composition. Eight of the twenty amino acids found belong to amino acids present in proteins. A number of monocarboxylic and dicarboxylic fatty acids were also found in the meteorites.

  2. 21 CFR 184.1005 - Acetic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acetic acid. 184.1005 Section 184.1005 Food and... Substances Affirmed as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation...

  3. Microbial production of natural poly amino acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Three kinds of poly amino acids, poly-γ-glutamic acid, poly(ε-L-lysine) and multi-L-arginyl-poly (L-aspartic acid) can be synthesized by enzymatic process independently from ribosomal protein biosynthesis pathways in microorganism. These biosynthesized polymers have attracted more and more attentions because of their unique properties and various applications. In this review, the current knowledge on the biosynthesis, biodegradations and applications of these three poly amino acids are summarized.

  4. Levulinic acid production from waste biomass

    OpenAIRE

    Anna Maria Raspolli Galletti,; Claudia Antonetti; Valentina De Luise,; Domenico Licursi,; Nicoletta Nassi

    2012-01-01

    The hydrothermal conversion of waste biomass to levulinic acid was investigated in the presence of homogeneous acid catalysts. Different cheap raw materials (poplar sawdust, paper mill sludge, tobacco chops, wheat straw, olive tree pruning) were employed as substrates. The yields of levulinic acid were improved by optimization of the main reaction parameters, such as type and amount of acid catalyst, temperature, duration, biomass concentration, and electrolyte addition. The catalytic perform...

  5. 21 CFR 184.1061 - Lactic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactic acid. 184.1061 Section 184.1061 Food and... Substances Affirmed as GRAS § 184.1061 Lactic acid. (a) Lactic acid (C3H6O3, CAS Reg. Nos.: dl mixture, 598-82-3; l-isomer, 79-33-4; d-isomer, 10326-41-7), the chemical 2-hydroxypropanoic acid, occurs...

  6. 21 CFR 573.480 - Formic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Formic acid. 573.480 Section 573.480 Food and... Listing § 573.480 Formic acid. Formic acid may be safely used as a preservative in hay crop silage in an.... The top foot of silage stored should not contain formic acid and silage should not be fed to livestock...

  7. Fatty Acid Composition of Agaricus bisporus (Lange) Sing.

    OpenAIRE

    Aktümsek, Abdurrahman; ÖZTÜRK, Celâleddin; KAŞIK, Giyasettin

    1998-01-01

    Fatty acid compositions of fruit body, stem, lamellae and total of Agaricus bisporus were seperately analysed by GLC. In the all fatty acid compositions of A. bisporus, linoleic acid were predominant. Percentages of linoleic acid were varied between 53.45 - 68.78%. It was showed that the other major fatty acids were palmitic, oleic and stearic acid in the fatty acid compositions.

  8. Chicoric Acid Found in Basil (Ocimum basilicum L.) Leaves

    Science.gov (United States)

    This is the first report to identify the presence of chicoric acid (cichoric acid; also known as dicaffeoyltartaric acid) in basil leaves. Rosmarinic acid, chicoric acid, and caftaric acid (in the order of most abundant to least; all derivatives of caffeic acid) were identified in fresh basil leaves...

  9. 21 CFR 172.130 - Dehydroacetic acid.

    Science.gov (United States)

    2010-04-01

    ... Food Preservatives § 172.130 Dehydroacetic acid. The food additive dehydroacetic acid and/or its sodium... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Dehydroacetic acid. 172.130 Section 172.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  10. 21 CFR 556.590 - Salicylic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Salicylic acid. 556.590 Section 556.590 Food and... Residues of New Animal Drugs § 556.590 Salicylic acid. A tolerance of zero is established for residues of salicylic acid in milk from dairy animals....

  11. Acrylic Acid and Esters Will Be Oversupply

    Institute of Scientific and Technical Information of China (English)

    Zheng Chengwang

    2007-01-01

    @@ Drastic capacity growth The production capacity of acrylic acid in China has grown drastically in recent years. With the completion of the 80 thousand t/a acrylic acid and 130 thous and t/a acrylic ester project in Shenyang Paraffin Chemical Industrial Co., Ltd., (CCR2006,No. 31) the capacity of acrylic acid in China has reached 882 thousand t/a.

  12. Tranexamic acid for upper gastrointestinal bleeding

    DEFF Research Database (Denmark)

    Gluud, Lise Lotte; Klingenberg, Sarah Louise; Langholz, Ebbe

    2012-01-01

    Tranexamic acid reduces haemorrhage through its antifibrinolytic effects. In a previous version of the present review, we found that tranexamic acid may reduce mortality. The present review includes updated searches of randomised trials on tranexamic acid versus placebo, cimetidine or lansoprazole....

  13. 21 CFR 582.1005 - Acetic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  14. More on Effects Controlling Carboxylic Acidity.

    Science.gov (United States)

    Schwartz, Lowell M.

    1981-01-01

    Gas phase acidity data shown are offered to writers of elementary organic chemistry texts for replacement of the aqueous phase data that are universally used. Relative acidities in the gas phase are controlled virtually exclusively by enthalpic factors. Structural-energetic explanations of acidic trends can therefore be used. (SK)

  15. Treating burns caused by hydrofluoric acid.

    Science.gov (United States)

    Summers, Anthony

    2011-06-01

    Hydrofluoric acid is an ingredient of many common household and industrial solutions. Even seemingly minor burns caused by this acid can have catastrophic effects if they are treated inappropriately or late. This article describes the signs and symptoms, the pathophysiology and the emergency management of hydrofluoric acid burns.

  16. 21 CFR 182.8013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ascorbic acid. 182.8013 Section 182.8013 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8013 Ascorbic acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized as safe when used...

  17. 21 CFR 182.3013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ascorbic acid. 182.3013 Section 182.3013 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3013 Ascorbic acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized as...

  18. 21 CFR 582.3013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ascorbic acid. 582.3013 Section 582.3013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Ascorbic acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized...

  19. Predicting folic acid intake among college students.

    Science.gov (United States)

    Lane, Susan H; Hines, Annette; Krowchuk, Heidi

    2015-01-01

    Annually in the United States, approximately 3,000 babies are born with neural tube defects (NTDs). Folic acid supplementation can reduce NTDs by 50% to 70%. Despite recommendations for folic acid intake, only 30% of women ages 18 to 24 report folic acid supplementation and 6% have knowledge of when to take folic acid. There is little information regarding lifestyle factors that correlate with consuming folic acid. The purpose was to describe folic acid consumption among college students; and explore the relationship between folic acid intake and the variables of: age, gender, year in college, alcohol and tobacco use, and vitamin supplement intake. This was a descriptive study with secondary analysis of data from 1,921 college-aged student participants in North Carolina who took part in a pretest/posttest-designed intervention to increase folic acid consumption and knowledge. Surveys included demographic, lifestyle, folic acid knowledge, and consumption questions adapted from the Centers for Disease Control and Prevention questionnaire. Quantitative analyses included descriptive statistics and logistic regression. Of the 1,921 college students, 83.3% reported taking a vitamin supplement, but only 47.6% stated that the vitamin contained folic acid. A relationship was found between age, year in school, gender, and vitamin intake. Lifestyle variables were not significant predictors of folic acid consumption. Identification of variables associated with folic acid intake, marketing, and education can be focused to increase supplementation levels, and ultimately reduce the number of NTDs.

  20. 21 CFR 582.1061 - Lactic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is...