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Sample records for resin acid biosynthesis

  1. Diterpene resin acids in conifers.

    Science.gov (United States)

    Keeling, Christopher I; Bohlmann, Jörg

    2006-11-01

    Diterpene resin acids are a significant component of conifer oleoresin, which is a viscous mixture of terpenoids present constitutively or inducibly upon herbivore or pathogen attack and comprises one form of chemical resistance to such attacks. This review focuses on the recent discoveries in the chemistry, biosynthesis, molecular biology, regulation, and biology of these compounds in conifers.

  2. Evolution of Diterpene Metabolism: Sitka Spruce CYP720B4 Catalyzes Multiple Oxidations in Resin Acid Biosynthesis of Conifer Defense against Insects1[C][W][OA

    Science.gov (United States)

    Hamberger, Björn; Ohnishi, Toshiyuki; Hamberger, Britta; Séguin, Armand; Bohlmann, Jörg

    2011-01-01

    Diterpene resin acids (DRAs) are specialized (secondary) metabolites of the oleoresin defense of conifers produced by diterpene synthases and cytochrome P450s of the CYP720B family. The evolution of DRA metabolism shares common origins with the biosynthesis of ent-kaurenoic acid, which is highly conserved in general (primary) metabolism of gibberellin biosynthesis. Transcriptome mining in species of spruce (Picea) and pine (Pinus) revealed CYP720Bs of four distinct clades. We cloned a comprehensive set of 12 different Sitka spruce (Picea sitchensis) CYP720Bs as full-length cDNAs. Spatial expression profiles, methyl jasmonate induction, and transcript enrichment in terpenoid-producing resin ducts suggested a role of CYP720B4 in DRA biosynthesis. CYP720B4 was characterized as a multisubstrate, multifunctional enzyme by the formation of oxygenated diterpenoids in metabolically engineered yeast, yeast in vivo transformation of diterpene substrates, in vitro assays with CYP720B4 protein produced in Escherichia coli, and alteration of DRA profiles in RNA interference-suppressed spruce seedlings. CYP720B4 was active with 24 different diterpenoid substrates, catalyzing consecutive C-18 oxidations in the biosynthesis of an array of diterpene alcohols, aldehydes, and acids. CYP720B4 was most active in the formation of dehydroabietic acid, a compound associated with insect resistance of Sitka spruce. We identified patterns of convergent evolution of CYP720B4 in DRA metabolism and ent-kaurene oxidase CYP701 in gibberellin metabolism and revealed differences in the evolution of specialized and general diterpene metabolism in a gymnosperm. The genomic and functional characterization of the gymnosperm CYP720B family highlights that the evolution of specialized metabolism involves substantial diversification relative to conserved, general metabolism. PMID:21994349

  3. Evolution of diterpene metabolism: Sitka spruce CYP720B4 catalyzes multiple oxidations in resin acid biosynthesis of conifer defense against insects.

    Science.gov (United States)

    Hamberger, Björn; Ohnishi, Toshiyuki; Hamberger, Britta; Séguin, Armand; Bohlmann, Jörg

    2011-12-01

    Diterpene resin acids (DRAs) are specialized (secondary) metabolites of the oleoresin defense of conifers produced by diterpene synthases and cytochrome P450s of the CYP720B family. The evolution of DRA metabolism shares common origins with the biosynthesis of ent-kaurenoic acid, which is highly conserved in general (primary) metabolism of gibberellin biosynthesis. Transcriptome mining in species of spruce (Picea) and pine (Pinus) revealed CYP720Bs of four distinct clades. We cloned a comprehensive set of 12 different Sitka spruce (Picea sitchensis) CYP720Bs as full-length cDNAs. Spatial expression profiles, methyl jasmonate induction, and transcript enrichment in terpenoid-producing resin ducts suggested a role of CYP720B4 in DRA biosynthesis. CYP720B4 was characterized as a multisubstrate, multifunctional enzyme by the formation of oxygenated diterpenoids in metabolically engineered yeast, yeast in vivo transformation of diterpene substrates, in vitro assays with CYP720B4 protein produced in Escherichia coli, and alteration of DRA profiles in RNA interference-suppressed spruce seedlings. CYP720B4 was active with 24 different diterpenoid substrates, catalyzing consecutive C-18 oxidations in the biosynthesis of an array of diterpene alcohols, aldehydes, and acids. CYP720B4 was most active in the formation of dehydroabietic acid, a compound associated with insect resistance of Sitka spruce. We identified patterns of convergent evolution of CYP720B4 in DRA metabolism and ent-kaurene oxidase CYP701 in gibberellin metabolism and revealed differences in the evolution of specialized and general diterpene metabolism in a gymnosperm. The genomic and functional characterization of the gymnosperm CYP720B family highlights that the evolution of specialized metabolism involves substantial diversification relative to conserved, general metabolism.

  4. Modularity of Conifer Diterpene Resin Acid Biosynthesis: P450 Enzymes of Different CYP720B Clades Use Alternative Substrates and Converge on the Same Products.

    Science.gov (United States)

    Geisler, Katrin; Jensen, Niels Berg; Yuen, Macaire M S; Madilao, Lina; Bohlmann, Jörg

    2016-05-01

    Cytochrome P450 enzymes of the CYP720B subfamily play a central role in the biosynthesis of diterpene resin acids (DRAs), which are a major component of the conifer oleoresin defense system. CYP720Bs exist in families of up to a dozen different members in conifer genomes and fall into four different clades (I-IV). Only two CYP720B members, loblolly pine (Pinus taeda) PtCYP720B1 and Sitka spruce (Picea sitchensis) PsCYP720B4, have been characterized previously. Both are multisubstrate and multifunctional clade III enzymes, which catalyze consecutive three-step oxidations in the conversion of diterpene olefins to DRAs. These reactions resemble the sequential diterpene oxidations affording ent-kaurenoic acid from ent-kaurene in gibberellin biosynthesis. Here, we functionally characterized the CYP720B clade I enzymes CYP720B2 and CYP720B12 in three different conifer species, Sitka spruce, lodgepole pine (Pinus contorta), and jack pine (Pinus banksiana), and compared their activities with those of the clade III enzymes CYP720B1 and CYP720B4 of the same species. Unlike the clade III enzymes, clade I enzymes were ultimately found not to be active with diterpene olefins but converted the recently discovered, unstable diterpene synthase product 13-hydroxy-8(14)-abietene. Through alternative routes, CYP720B enzymes of both clades produce some of the same profiles of conifer oleoresin DRAs (abietic acid, neoabietic acid, levopimaric acid, and palustric acid), while clade III enzymes also function in the formation of pimaric acid, isopimaric acid, and sandaracopimaric acid. These results highlight the modularity of the specialized (i.e. secondary) diterpene metabolism, which produces conifer defense metabolites through variable combinations of different diterpene synthase and CYP720B enzymes. © 2016 American Society of Plant Biologists. All Rights Reserved.

  5. Cloning and expression of a CYP720B orthologue involved in the biosynthesis of diterpene resin acids in Pinus brutia.

    Science.gov (United States)

    Semiz, Asli; Sen, Alaattin

    2015-03-01

    Cytochrome P450 monooxygenases mediate a broad range of oxidative reactions involved in the biosynthesis of both primary and secondary metabolites in plants. Until now, only two P450 genes, CYP720B1 from Pinus taeda and CYP720B4 from Picea sitchensis, have been functionally characterised and described in the literature. The purpose of this study was to describe the cloning and expression of CYP720B from Pinus brutia due to its suggested role in the synthesis of bioactive compounds used for chemical defence against insects. A PCR product of the P. brutia CYP720B gene was cloned into the pCR8/GW/TOPO cloning vector. After optimising the sequence for codon usage in yeast, it was transferred into the inducible expression vector pYES-DEST52 and transfected into the S. cerevisiae INVSc1 strain. Sequence analysis showed that the P. brutia CYP720B gene contains an open reading frame of 1,464 nucleotides, which encodes a 53,570 Da putative protein of 487 amino acid residues. The putative protein contains the classic heme-binding sequence motif that is conserved in all P450 enzymes. It shares 99 and 61% identity with the deduced amino acid sequences of CYP720B1 from Pinus taeda and CYP720B4 from Picea sitchensis, respectively. Recombinant CYP720B protein expression was confirmed using western blot analysis. Furthermore, recombinant CYP720B was functionally active, showing a Soret peak at approximately 448 nm in the reduced CO difference spectra. These data suggest that the cloned gene is an orthologue of CYP720B in P. brutia and might be involved in DRA biosynthesis.

  6. Evolution of Conifer Diterpene Synthases: Diterpene Resin Acid Biosynthesis in Lodgepole Pine and Jack Pine Involves Monofunctional and Bifunctional Diterpene Synthases1[W][OA

    Science.gov (United States)

    Hall, Dawn E.; Zerbe, Philipp; Jancsik, Sharon; Quesada, Alfonso Lara; Dullat, Harpreet; Madilao, Lina L.; Yuen, Macaire; Bohlmann, Jörg

    2013-01-01

    Diterpene resin acids (DRAs) are major components of pine (Pinus spp.) oleoresin. They play critical roles in conifer defense against insects and pathogens and as a renewable resource for industrial bioproducts. The core structures of DRAs are formed in secondary (i.e. specialized) metabolism via cycloisomerization of geranylgeranyl diphosphate (GGPP) by diterpene synthases (diTPSs). Previously described gymnosperm diTPSs of DRA biosynthesis are bifunctional enzymes that catalyze the initial bicyclization of GGPP followed by rearrangement of a (+)-copalyl diphosphate intermediate at two discrete class II and class I active sites. In contrast, similar diterpenes of gibberellin primary (i.e. general) metabolism are produced by the consecutive activity of two monofunctional class II and class I diTPSs. Using high-throughput transcriptome sequencing, we discovered 11 diTPS from jack pine (Pinus banksiana) and lodgepole pine (Pinus contorta). Three of these were orthologous to known conifer bifunctional levopimaradiene/abietadiene synthases. Surprisingly, two sets of orthologous PbdiTPSs and PcdiTPSs were monofunctional class I enzymes that lacked functional class II active sites and converted (+)-copalyl diphosphate, but not GGPP, into isopimaradiene and pimaradiene as major products. Diterpene profiles and transcriptome sequences of lodgepole pine and jack pine are consistent with roles for these diTPSs in DRA biosynthesis. The monofunctional class I diTPSs of DRA biosynthesis form a new clade within the gymnosperm-specific TPS-d3 subfamily that evolved from bifunctional diTPS rather than monofunctional enzymes (TPS-c and TPS-e) of gibberellin metabolism. Homology modeling suggested alterations in the class I active site that may have contributed to their functional specialization relative to other conifer diTPSs. PMID:23370714

  7. Evolution of conifer diterpene synthases: diterpene resin acid biosynthesis in lodgepole pine and jack pine involves monofunctional and bifunctional diterpene synthases.

    Science.gov (United States)

    Hall, Dawn E; Zerbe, Philipp; Jancsik, Sharon; Quesada, Alfonso Lara; Dullat, Harpreet; Madilao, Lina L; Yuen, Macaire; Bohlmann, Jörg

    2013-02-01

    Diterpene resin acids (DRAs) are major components of pine (Pinus spp.) oleoresin. They play critical roles in conifer defense against insects and pathogens and as a renewable resource for industrial bioproducts. The core structures of DRAs are formed in secondary (i.e. specialized) metabolism via cycloisomerization of geranylgeranyl diphosphate (GGPP) by diterpene synthases (diTPSs). Previously described gymnosperm diTPSs of DRA biosynthesis are bifunctional enzymes that catalyze the initial bicyclization of GGPP followed by rearrangement of a (+)-copalyl diphosphate intermediate at two discrete class II and class I active sites. In contrast, similar diterpenes of gibberellin primary (i.e. general) metabolism are produced by the consecutive activity of two monofunctional class II and class I diTPSs. Using high-throughput transcriptome sequencing, we discovered 11 diTPS from jack pine (Pinus banksiana) and lodgepole pine (Pinus contorta). Three of these were orthologous to known conifer bifunctional levopimaradiene/abietadiene synthases. Surprisingly, two sets of orthologous PbdiTPSs and PcdiTPSs were monofunctional class I enzymes that lacked functional class II active sites and converted (+)-copalyl diphosphate, but not GGPP, into isopimaradiene and pimaradiene as major products. Diterpene profiles and transcriptome sequences of lodgepole pine and jack pine are consistent with roles for these diTPSs in DRA biosynthesis. The monofunctional class I diTPSs of DRA biosynthesis form a new clade within the gymnosperm-specific TPS-d3 subfamily that evolved from bifunctional diTPS rather than monofunctional enzymes (TPS-c and TPS-e) of gibberellin metabolism. Homology modeling suggested alterations in the class I active site that may have contributed to their functional specialization relative to other conifer diTPSs.

  8. [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.

  9. 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...

  10. Fatty acid biosynthesis in actinomycetes

    Science.gov (United States)

    Gago, Gabriela; Diacovich, Lautaro; Arabolaza, Ana; Tsai, Shiou-Chuan; Gramajo, Hugo

    2011-01-01

    All organisms that produce fatty acids do so via a repeated cycle of reactions. In mammals and other animals, these reactions are catalyzed by a type I fatty acid synthase (FAS), a large multifunctional protein to which the growing chain is covalently attached. In contrast, most bacteria (and plants) contain a type II system in which each reaction is catalyzed by a discrete protein. The pathway of fatty acid biosynthesis in Escherichia coli is well established and has provided a foundation for elucidating the type II FAS pathways in other bacteria (White et al., 2005). However, fatty acid biosynthesis is more diverse in the phylum Actinobacteria: Mycobacterium, possess both FAS systems while Streptomyces species have only the multi-enzyme FAS II system and Corynebacterium species exclusively FAS I. In this review we present an overview of the genome organization, biochemical properties and physiological relevance of the two FAS systems in the three genera of actinomycetes mentioned above. We also address in detail the biochemical and structural properties of the acyl-CoA carboxylases (ACCases) that catalyzes the first committed step of fatty acid synthesis in actinomycetes, and discuss the molecular bases of their substrate specificity and the structure-based identification of new ACCase inhibitors with anti-mycobacterial properties. PMID:21204864

  11. Antibacterial Targets in Fatty Acid Biosynthesis

    Science.gov (United States)

    Wright, H. Tonie; Reynolds, Kevin A.

    2008-01-01

    Summary The fatty acid biosynthesis pathway is an attractive but still largely unexploited target for development of new anti-bacterial agents. The extended use of the anti-tuberculosis drug isoniazid and the antiseptic triclosan, which are inhibitors of fatty acid biosynthesis, validates this pathway as a target for anti-bacterial development. Differences in subcellular organization of the bacterial and eukaryotic multi-enzyme fatty acid synthase systems offer the prospect of inhibitors with host vs. target specificity. Platensimycin, platencin, and phomallenic acids, newly discovered natural product inhibitors of the condensation steps in fatty acid biosynthesis, represent new classes of compounds with antibiotic potential. An almost complete catalogue of crystal structures for the enzymes of the type II fatty acid biosynthesis pathway can now be exploited in the rational design of new inhibitors, as well as the recently published crystal structures of type I FAS complexes. PMID:17707686

  12. Biosynthesis and biotransformation of bile acids

    Directory of Open Access Journals (Sweden)

    Šarenac Tanja M.

    2017-01-01

    Full Text Available Bile acids are steroidal compounds, which contain 24 carbon atoms. They can be classified into two major groups: primary and secondary. The most abundant bile acids: The primary bile acids include cholic acid and chenodeoxycholic acid, while the major secondary bile acids are deoxycholic acid and litocholic acid. Bile acids are important physiological agents for intestinal absorption of nutrients and are used for biliary lipid secretion, toxic metabolites and xenobiotics. The aim of this paper is to analyze biosynthesis and biotransformation of bile acids, as preparation for practical usage in laboratory and clinical conditions. Topic: Biosynthesis and biotransformation of bile acids: The biosynthesis of bile acids is the dominant metabolic pathway for catabolism of cholesterol in humans. The classical route of biosynthesis of bile acids is embarking on the conversion of cholesterol into 7α-hydroxycholesterol using enzyme 7α-cholesterol hydroxylase (CYP7A1. This enzyme is one of the microsomal cytochrome P450 enzyme is localized exclusively in the liver. Classical road is the main road in the biosynthesis of bile acids, and its total contribution amounts to 90% for people, and 75% in mice. CYP 7A1 enzyme is considered to be sensitive to the inhibition of carbon monoxide, and the condition for the effect of NADPH, the oxygen, lecithin, and the NADPH-cytochrome P450 reductase. Bile acids are important signaling molecules and metabolic controls which activate the nuclear receptor and the G protein-coupled receptors (GPCR, a signaling lipid regulation of the liver, glucose and energy homeostasis. Also, bile acids maintain metabolic homeostasis. Biotransformation of bile acids: The conversion of cholesterol into bile acids just important for maintenance of cholesterol homeostasis, but also to prevent the accumulation of cholesterol, triglycerides and toxic metabolites as well as violations of the liver and other organs. Enterohepatic circulation of

  13. Bile acid biosynthesis and its regulation

    Directory of Open Access Journals (Sweden)

    Areta Hebanowska

    2010-10-01

    Full Text Available Bile acid biosynthesis is the main pathway of cholesterol catabolism. Bile acids are more soluble than cholesterol so are easier to excrete. As amphipathic molecules they participate in lipid digestion and absorption in the intestine and they help to excrete free cholesterol with bile. They are also ligands for nuclear receptors regulating the expression of genes involved in cholesterol metabolism. Interconversion of cholesterol into bile acids is an important point of its homeostasis. Seventeen enzymes are engaged in this process and many of them are cytochromes P450. Bile acid synthesis initiation may proceed with the “classical” pathway (starting with cholesterol hydroxylation at the C7α position or the “alternative” pathway (starting with cholesterol hydroxylation at the C27 position. Two additional pathways are possible, though their quantitative significance is small (initiated with cholesterol hydroxylations of C24 and C25 positions. Oxysterols produced are not only intermediates of bile acid biosynthesis but also important regulators of metabolism. Bile acid biosynthesis takes place in the liver, but some enzymes are also present in other organs, where they participate in regulation of cholesterol metabolism. Those enzymes are potential targets for new drugs against cholesterol metabolism disturbances. This article is a brief description of the bile acid biosynthesis pathway and participating enzymes.

  14. Biosynthesis and metabolic pathways of pivalic acid

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Kolouchová, I.; Čejková, A.; Sigler, Karel

    2012-01-01

    Roč. 95, č. 6 (2012), s. 1371-1376 ISSN 0175-7598 R&D Projects: GA ČR(CZ) GAP503/11/0215 Institutional support: RVO:61388971 Keywords : Pivalic acid * Isooctane * Biosynthesis Subject RIV: EE - Microbiology, Virology Impact factor: 3.689, year: 2012

  15. 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.

  16. Diterpene resin acid biosynthesis in loblolly pine (Pinus taeda): functional characterization of abietadiene/levopimaradiene synthase (PtTPS-LAS) cDNA and subcellular targeting of PtTPS-LAS and abietadienol/abietadienal oxidase (PtAO, CYP720B1).

    Science.gov (United States)

    Ro, Dae-Kyun; Bohlmann, Jörg

    2006-08-01

    Diterpene resin acids are prominent defense compounds against insect pests and pathogens in conifers. Biochemical and molecular analyses in grand fir (Abies grandis), Norway spruce (Picea abies), and loblolly pine (Pinus taeda) have identified two classes of genes and enzymes that generate much of the structural diversity of terpenoid defense compounds: The terpenoid synthases (TPS) and cytochrome P450 monooxgenases (P450). Using a single substrate, geranylgeranyl diphosphate, families of single-product and multi-product diterpene synthases generate an array of cyclic diterpene olefins. These diterpenes are converted to diterpene resin acids by activity of one or more P450 enzymes. A few conifer diterpene synthases have previously been cloned and characterized in grand fir and in Norway spruce. We have also previously shown that the loblolly pine P450 abietadienol/abietadienal oxidase (PtAO) catalyzes multiple oxidations of several diterpene alcohols and aldehydes. Conifer diterpene synthases are thought to function in plastids while P450s can also be localized to plastids or to the endoplasmic reticulum (ER). Here, we show that a loblolly pine cDNA (PtTPS-LAS) encodes a typical multi-product conifer diterpene synthase that forms levopimaradiene, abietadiene, palustradiene, and neoabietadiene similar to the grand fir abietadiene synthase and Norway spruce levopimaradiene/abietadiene synthase. Subcellular targeting of PtTPS-LAS and PtAO to plastids and ER, respectively, was shown with green fluorescent fusion protein expression in tobacco cells. These data suggest that enzymes for conifer diterpene resin acid biosynthesis are localized to at least two different subcellular compartments, plastids and ER, requiring efficient transport of intermediates and secretion of diterpene resin acids into the extracelluar space.

  17. Fatty acid biosynthesis in pea root plastids

    International Nuclear Information System (INIS)

    Stahl, R.J.; Sparace, S.A.

    1989-01-01

    Fatty acid biosynthesis from [1- 14 C]acetate was optimized in plastids isolated from primary root tips of 7-day-old germinating pea seeds. Fatty acid synthesis was maximum at approximately 80 nmoles/hr/mg protein in the presence of 200 μM acetate, 0.5 mM each of NADH, NADPH and CoA, 6 mM each of ATP and MgCl 2 , 1 mM each of the MnCl 2 and glycerol-3-phosphate, 15 mM KHCO 3 , and 0.1M Bis-tris-propane, pH 8.0 incubated at 35C. At the standard incubation temperature of 25C, fatty acid synthesis was linear from up to 6 hours with 80 to 100 μg/mL plastid protein. ATP and CoA were absolute requirements, whereas KHCO 3 , divalent cations and reduced nucleotides all improved activity by 80 to 85%. Mg 2+ and NADH were the preferred cation and nucleotide, respectively. Dithiothreitol and detergents were generally inhibitory. The radioactive products of fatty acid biosynthesis were approximately 33% 16:0, 10% 18:0 and 56% 18:1 and generally did not vary with increasing concentrations of each cofactor

  18. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573.120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin...

  19. Biosynthesis of myristic acid in luminescent bacteria

    International Nuclear Information System (INIS)

    Byers, D.M.

    1987-01-01

    In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with [ 14 C] acetate in a nutrient-depleted medium accumulated substantial tree [ 14 C]fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with [ 14 C]acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition

  20. Engineering E. coli for caffeic acid biosynthesis from renewable sugars.

    Science.gov (United States)

    Zhang, Haoran; Stephanopoulos, Gregory

    2013-04-01

    Caffeic acid is a valuable aromatic compound that possesses many important pharmacological activities. In structure, caffeic acid belongs to the hydroxycinnamic acid family and can be biosynthesized from the aromatic amino acid tyrosine. In the present paper, the caffeic acid biosynthesis pathway was reconstituted in engineered Escherichia coli to produce caffeic acid from simple biomass sugar glucose and xylose. Different engineering approaches were utilized to optimize the production. Specifically, two parallel biosynthesis routes leading from tyrosine to caffeic acid were studied. The copy number of the intermediate biosynthesis genes was varied to find appropriate gene doses for caffeic acid biosynthesis. Three different media, including a MOPS medium, a synthetic medium, and a rich medium, were also examined to improve the production. The highest specific caffeic acid production achieved was 38 mg/L/OD. Lastly, cultivation of engineered E. coli in a bioreactor resulted in a production of 106 mg/L caffeic acid after 4 days.

  1. Methyl Jasmonate Induces Traumatic Resin Ducts, Terpenoid Resin Biosynthesis, and Terpenoid Accumulation in Developing Xylem of Norway Spruce Stems1

    Science.gov (United States)

    Martin, Diane; Tholl, Dorothea; Gershenzon, Jonathan; Bohlmann, Jörg

    2002-01-01

    Norway spruce (Picea abies L. Karst) produces an oleoresin characterized by a diverse array of terpenoids, monoterpenoids, sesquiterpenoids, and diterpene resin acids that can protect conifers against potential herbivores and pathogens. Oleoresin accumulates constitutively in resin ducts in the cortex and phloem (bark) of Norway spruce stems. De novo formation of traumatic resin ducts (TDs) is observed in the developing secondary xylem (wood) after insect attack, fungal elicitation, and mechanical wounding. Here, we characterize the methyl jasmonate-induced formation of TDs in Norway spruce by microscopy, chemical analyses of resin composition, and assays of terpenoid biosynthetic enzymes. The response involves tissue-specific differentiation of TDs, terpenoid accumulation, and induction of enzyme activities of both prenyltransferases and terpene synthases in the developing xylem, a tissue that constitutively lacks axial resin ducts in spruce. The induction of a complex defense response in Norway spruce by methyl jasmonate application provides new avenues to evaluate the role of resin defenses for protection of conifers against destructive pests such as white pine weevils (Pissodes strobi), bark beetles (Coleoptera, Scolytidae), and insect-associated tree pathogens. PMID:12114556

  2. Antimicrobial activity of resin acid derivatives.

    Science.gov (United States)

    Savluchinske-Feio, Sonia; Curto, Maria João Marcelo; Gigante, Bárbara; Roseiro, J Carlos

    2006-09-01

    The wide potential of resin acids as bioactive agents gave rise to a growing effort in the search for new applications of the natural forms and their derivatives. In some of these compounds, the antimicrobial activity is associated to the presence in the molecules of functional groups such as the hydroxyl, aldehyde, and ketone or to their cis or trans configurations. The resin acid family covers a spectrum of antimicrobial activities against several microorganisms, from bacteria to fungi, in which the mode of action was studied by electron microscopy. The morphological alterations are consistent with an unspecific mode of action causing inhibition of the fungal growth or damaging the fungal cells in parallel with a mechanism of resistance based on the retention of the compound by the lipid accumulation. The sterol composition of phytopathogenic fungi Botrytis cinerea and Lophodermium seditiosum treated with methyl cis-7-oxo-deisopropyldehydroabietate revealed the presence of ergosterol (M+ 396) and dihydroergosterol (M+ 398) in both cultures showing that this compound did not interfere with the ergosterol metabolic pathway of both fungi.

  3. Kinetic study of ion exchange in phosphoric acid chelating resin

    International Nuclear Information System (INIS)

    Brikci-Nigassa, Mounir; Hamouche, Hafida

    1995-11-01

    Uranium may be recovered as a by product of wet phosphoric acid using a method based on specific ion exchange resins. These resins called chelates contain amino-phosphonic functional groups. The resin studied in this work is a purolite S-940; uranium may be loaded on this resin from 30% P2O5 phosphoric acid in its reduced state. The influence of different parameters on the successive steps of the process have been studied in batch experiments: uranium reduction, loading and oxydation. Uranium may be eluted with ammonium carbonate and the resin regeneration may be done with hydrochloric acid.Ferric ions reduce the effective resin capacity considerably and inert fixation conditions are proposed to enhance uranium loading

  4. Isolation of carbon 14 labelled amino acids by biosynthesis in maize plants (zea mais L.)

    International Nuclear Information System (INIS)

    Carreras, N.; Mazon, M.P.

    1983-01-01

    A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14 CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 CO 2 produced from Ba 14 CO 3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic columns (Dowex 50-X4). (author)

  5. Isolation of 14C labelled amino acids by biosynthesis in maize plants (Zea mais L.)

    International Nuclear Information System (INIS)

    Carreras, N.; Mazon, M.P.

    1983-01-01

    A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 C O2 produced from Ba 14 C O3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic column (Dowex 50-X4). (Author) 56 refs

  6. Inhibitors of amino acids biosynthesis as antifungal agents.

    Science.gov (United States)

    Jastrzębowska, Kamila; Gabriel, Iwona

    2015-02-01

    Fungal microorganisms, including the human pathogenic yeast and filamentous fungi, are able to synthesize all proteinogenic amino acids, including nine that are essential for humans. A number of enzymes catalyzing particular steps of human-essential amino acid biosynthesis are fungi specific. Numerous studies have shown that auxotrophic mutants of human pathogenic fungi impaired in biosynthesis of particular amino acids exhibit growth defect or at least reduced virulence under in vivo conditions. Several chemical compounds inhibiting activity of one of these enzymes exhibit good antifungal in vitro activity in minimal growth media, which is not always confirmed under in vivo conditions. This article provides a comprehensive overview of the present knowledge on pathways of amino acids biosynthesis in fungi, with a special emphasis put on enzymes catalyzing particular steps of these pathways as potential targets for antifungal chemotherapy.

  7. Chelating ion exchange with macroreticular hydroxamic acid resins

    International Nuclear Information System (INIS)

    Phillips, R.J.

    1980-01-01

    The synthesis, reactions, and analytical applications of hydroxamic acids, including chelating resins with this functional group, are reviewed. A procedure for attaching N-phenyl hydroxamic acid groups to Amberlite XAD-4 is described. The extraction of 20 metal ions from 2M hydrochloric acid by this resin is discussed. Conditions for the quantitative extraction and back-extraction of 9 ions are reported. The results are compared with work on solvent extraction with N-phenylbenzohydroxamic acid. Procedures for attaching N-methyl and N-substituted hydroxamic acid groups to Amberlite XAD-4 are described. The N-phenyl, N-methyl, and N-unsubstituted hydroxamic acid resins are compared with respect to metal-ion complexation. The scope of applications for hydroxamic acid resins is investigated by studying the extraction of 19 metal ions as a function of pH. The resins are especially suitable for the extraction of zirconium(IV), titanium(IV), and uranium(IV) from strongly acidic solution. Aluminum(III) is separated from calcium and phosphate by extraction at pH 4. The use of the resins for the purification of reagents, concentration of trace constituents, and chromatographic separation is demonstrated

  8. Chelating ion exchange with macroreticular hydroxamic acid resins

    International Nuclear Information System (INIS)

    Phillips, R.J.

    1980-01-01

    The synthesis, reactions, and analytical applications of hydroxamic acids, including chelating resins with this functional group, are reviewed. A procedure for attaching N-phenyl hydroxamic acid groups to Amberlite XAD-4 is described. The extraction of 20 metal ions from 2 M hydrochloric acid by this resin is discussed. Conditions for the quantitative extraction and back-extraction of 9 ions are reported. Results are compared with work on solvent extraction with N-phenylbenzohydroxamic acid. Procedures for attaching N-methyl and N-unsubstituted hydroxamic acid groups to Amberlite XAD-4 are described. The N-phenyl, N-methyl, and N-unsubstituted hydroxamic acid resins are compared with respect to metal-ion complexation. The scope of applications for hydroxamic acid resins is investigated by studying the extraction of 19 metal ions as a function of pH. The resins are especially suitable for the extraction of zirconium(IV), titanium(IV), and uranium(IV) from strongly acidic solution. Aluminum(III) is separated from calcium and phosphate by extraction at pH 4. The use of the resins for the purification of reagents, concentration of trace constituents, and chromatographic separation is demonstrated

  9. Enhanced vanillin production from ferulic acid using adsorbent resin.

    Science.gov (United States)

    Hua, Dongliang; Ma, Cuiqing; Song, Lifu; Lin, Shan; Zhang, Zhaobin; Deng, Zixin; Xu, Ping

    2007-03-01

    High vanillin productivity was achieved in the batch biotransformation of ferulic acid by Streptomyces sp. strain V-1. Due to the toxicity of vanillin and the product inhibition, fed-batch biotransformation with high concentration of ferulic acid was unsuccessful. To solve this problem and improve the vanillin yield, a biotransformation strategy using adsorbent resin was investigated. Several macroporous adsorbent resins were chosen to adsorb vanillin in situ during the bioconversion. Resin DM11 was found to be the best, which adsorbed the most vanillin and the least ferulic acid. When 8% resin DM11 (wet w/v) was added to the biotransformation system, 45 g l(-1) ferulic acid could be added continually and 19.2 g l(-1) vanillin was obtained within 55 h, which was the highest vanillin yield by bioconversion until now. This yield was remarkable for exceeding the crystallization concentration of vanillin and therefore had far-reaching consequence in its downstream processing.

  10. Engineering fatty acid biosynthesis in microalgae for sustainable biodiesel.

    Science.gov (United States)

    Blatti, Jillian L; Michaud, Jennifer; Burkart, Michael D

    2013-06-01

    Microalgae are a promising feedstock for biodiesel and other liquid fuels due to their fast growth rate, high lipid yields, and ability to grow in a broad range of environments. However, many microalgae achieve maximal lipid yields only under stress conditions hindering growth and providing compositions not ideal for biofuel applications. Metabolic engineering of algal fatty acid biosynthesis promises to create strains capable of economically producing fungible and sustainable biofuels. The algal fatty acid biosynthetic pathway has been deduced by homology to bacterial and plant systems, and much of our understanding is gleaned from basic studies in these systems. However, successful engineering of lipid metabolism in algae will necessitate a thorough characterization of the algal fatty acid synthase (FAS) including protein-protein interactions and regulation. This review describes recent efforts to engineer fatty acid biosynthesis toward optimizing microalgae as a biodiesel feedstock. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. In Vivo Roles of Fatty Acid Biosynthesis Enzymes in Biosynthesis of Biotin and α-Lipoic Acid in Corynebacterium glutamicum.

    Science.gov (United States)

    Ikeda, Masato; Nagashima, Takashi; Nakamura, Eri; Kato, Ryosuke; Ohshita, Masakazu; Hayashi, Mikiro; Takeno, Seiki

    2017-10-01

    For fatty acid biosynthesis, Corynebacterium glutamicum uses two type I fatty acid synthases (FAS-I), FasA and FasB, in addition to acetyl-coenzyme A (CoA) carboxylase (ACC) consisting of AccBC, AccD1, and AccE. The in vivo roles of the enzymes in supplying precursors for biotin and α-lipoic acid remain unclear. Here, we report genetic evidence demonstrating that the biosynthesis of these cofactors is linked to fatty acid biosynthesis through the FAS-I pathway. For this study, we used wild-type C. glutamicum and its derived biotin vitamer producer BFI-5, which was engineered to express Escherichia coli bioBF and Bacillus subtilis bioI Disruption of either fasA or fasB in strain BFI-5 led to decreased production of biotin vitamers, whereas its amplification contributed to increased production, with a larger impact of fasA in both cases. Double disruptions of fasA and fasB resulted in no biotin vitamer production. The acc genes showed a positive effect on production when amplified simultaneously. Augmented fatty acid biosynthesis was also reflected in pimelic acid production when carbon flow was blocked at the BioF reaction. These results indicate that carbon flow down the FAS-I pathway is destined for channeling into the biotin biosynthesis pathway, and that FasA in particular has a significant impact on precursor supply. In contrast, fasB disruption resulted in auxotrophy for lipoic acid or its precursor octanoic acid in both wild-type and BFI-5 strains. The phenotypes were fully complemented by plasmid-mediated expression of fasB but not fasA These results reveal that FasB plays a specific physiological role in lipoic acid biosynthesis in C. glutamicum IMPORTANCE For the de novo biosynthesis of fatty acids, C. glutamicum exceptionally uses a eukaryotic multifunctional type I fatty acid synthase (FAS-I) system comprising FasA and FasB, in contrast to most bacteria, such as E. coli and B. subtilis , which use an individual nonaggregating type II fatty acid synthase

  12. Uranium extraction from sulfuric acid solution using anion exchange resin

    International Nuclear Information System (INIS)

    Sheta, M. E.; Abdel Aal, M. M.; Kandil, A. T.

    2012-12-01

    Uranium is currently recovered from sulfuric acid leach liquor using anion exchange resin as Amberlite IRA 402 (CT). This technology is based on fact that, uranium exists as anionic complexes. This takes place by controlling the pH of the solution, agitation time, temperature and resin to solution ratio (R/S). In this work, batch stirrer tank used for uranium extraction from sulfate medium and after extraction, elution process was done using 1M NaCl solution. After extraction and elution process, the resin was separated from the system and uranium was determined in the solution. (Author)

  13. Biosynthesis of butyric acid by Clostridium tyrobutyricum.

    Science.gov (United States)

    Huang, Jin; Tang, Wan; Zhu, Shengquan; Du, Meini

    2018-03-21

    Butyric acid (C 3 H 7 COOH) is an important chemical that is widely used in foodstuffs along with in the chemical and pharmaceutical industries. The bioproduction of butyric acid via large-scale fermentation has the potential to be more economical and efficient than petrochemical synthesis. In this paper, the metabolic pathways involved in the production of butyric acid from Clostridium tyrobutyricum using hexose and pentose as substrates are investigated, and approaches to enhance butyric acid production via genetic modification are discussed. Finally, bioreactor modifications (including fibrous bed bioreactor, inner disc-shaped matrix bioreactor, fibrous matrix packed in porous levitated sphere carriers), low-cost feedstocks and special treatments (including continuous fermentation with cell recycling, extractive fermentation with solvent, using different artificial electron carriers) intended to improve the feasibility of commercial butyric acid bioproduction are summarized.

  14. Selective separation of indium by iminodiacetic acid chelating resin

    Energy Technology Data Exchange (ETDEWEB)

    Fortes, M.C.B.; Benedetto, J.S. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Martins, A.H. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Metalurgica e de Materiais]. E-mail: ahmartin@demet.ufmg.br

    2007-04-15

    - Indium can be recovered by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting. This paper investigates the adsorption characteristics of indium and iron on an iminodiacetic acid chelating resin, Amberlite{sup R} IRC748 (Rohm and Haas Co.-USA). High concentrations of iron are always present in the aqueous feed solution of indium recovery. In addition, the chemical behaviour of iron in adsorptive systems is similar to that of indium. The metal concentrations in the aqueous solution were based on typical indium sulfate leach liquor obtained from zinc hydrometallurgical processing in a Brazilian plant. The ionic adsorption experiments were carried out by the continuous column method. Amberlite{sup R} IRC748 resin had a high affinity for indium under acidic conditions. Indium ions adsorbed onto the polymeric resin were eluted with a 0.5 mol/dm{sup 3} sulphuric acid solution passed through the resin bed in the column. 99.5% pure indium sulfate aqueous solution was obtained using the iminodiacetic acid chelating resin Amberlite{sup R} IRC748. (author)

  15. GENETIC ANALYSIS OF ABSCISIC ACID BIOSYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    MCCARTY D R

    2012-01-10

    The carotenoid cleavage dioxygenases (CCD) catalyze synthesis of a variety of apo-carotenoid secondary metabolites in plants, animals and bacteria. In plants, the reaction catalyzed by the 11, 12, 9-cis-epoxy carotenoid dioxygenase (NCED) is the first committed and key regulated step in synthesis of the plant hormone, abscisic acid (ABA). ABA is a key regulator of plant stress responses and has critical functions in normal root and seed development. The molecular mechanisms responsible for developmental control of ABA synthesis in plant tissues are poorly understood. Five of the nine CCD genes present in the Arabidopsis genome encode NCED's involved in control of ABA synthesis in the plant. This project is focused on functional analysis of these five AtNCED genes as a key to understanding developmental regulation of ABA synthesis and dissecting the role of ABA in plant development. For this purpose, the project developed a comprehensive set of gene knockouts in the AtNCED genes that facilitate genetic dissection of ABA synthesis. These mutants were used in combination with key molecular tools to address the following specific objectives: (1) the role of ABA synthesis in root development; (2) developmental control of ABA synthesis in seeds; (3) analysis of ATNCED over-expressers; (4) preliminary crystallography of the maize VP14 protein.

  16. Curcumin improves alcoholic fatty liver by inhibiting fatty acid biosynthesis.

    Science.gov (United States)

    Guo, Chang; Ma, Jingfan; Zhong, Qionghong; Zhao, Mengyuan; Hu, Tianxing; Chen, Tong; Qiu, Longxin; Wen, Longping

    2017-08-01

    Alcoholic fatty liver is a threat to human health. It has been long known that abstinence from alcohol is the most effective therapy, other effective therapies are not available for the treatment in humans. Curcumin has a great potential for anti-oxidation and anti-inflammation, but the effect on metabolic reconstruction remains little known. Here we performed metabolomic analysis by gas chromatography/mass spectrometry and explored ethanol pathogenic insight as well as curcumin action pattern. We identified seventy-one metabolites in mouse liver. Carbohydrates and lipids were characteristic categories. Pathway analysis results revealed that ethanol-induced pathways including biosynthesis of unsaturated fatty acids, fatty acid biosynthesis and pentose and glucuronate interconversions were suppressed by curcumin. Additionally, ethanol enhanced galactose metabolism and pentose phosphate pathway. Glyoxylate and dicarboxylate metabolism and pyruvate metabolism were inhibited in mice fed ethanol diet plus curcumin. Stearic acid, oleic acid and linoleic acid were disease biomarkers and therapical biomarkers. These results reflect the landscape of hepatic metabolism regulation. Our findings illustrate ethanol pathological pathway and metabolic mechanism of curcumin therapy. Copyright © 2017. Published by Elsevier Inc.

  17. [Absorption and isolation of macroporous resin for five salvianolic acids from Salviae mitiorrhizae].

    Science.gov (United States)

    Wang, Yan-Yan; Zhu, Jing-Bo; Li, Lin; Jin, Yue

    2008-05-01

    To study the adsorption of the macroporous resin for the five salvianolic acids (danshen su, rosmarinic acid, protocate chualdehyde, salvianolic acid B, salvianolic acid A, extracted from Salviae mitiorrhizae. The five salvianolic acids were employed as an index, and the change of them in the static and dynamic absorbent was detected by HPLC, respectively. HP20 resin was a suitable marcoporous resin to purify salvianolic acids. The dynamic adsorption capacity of rosmarinic acid, salvianolic acid B and salvianolic acid A was 30.506 mg x g(-1) (dry resin), 36.996 mg x g(-1), (dry resin), 43.85 mg x g(-1) (dry resin) respectively. It is not suitable that danshensu and protocate chualdehyde are the evaluation indexes for using 8 macroporous resins to purify salvianolic acids.

  18. Plant amino acid-derived vitamins: biosynthesis and function.

    Science.gov (United States)

    Miret, Javier A; Munné-Bosch, Sergi

    2014-04-01

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

  19. Bile acid sequestrants : more than simple resins

    NARCIS (Netherlands)

    Out, Carolien; Groen, Albert K.; Brufau, Gemma

    Purpose of review Bile acid sequestrants (BAS) have been used for more than 50 years in the treatment of hypercholesterolemia. The last decade, bile acids are emerging as integrated regulators of metabolism via induction of various signal transduction pathways. Consequently, BAS treatment may exert

  20. Genetic Dissection of Tropodithietic Acid Biosynthesis by Marine Roseobacters

    DEFF Research Database (Denmark)

    Geng, Haifeng; Bruhn, Jesper Bartholin; Nielsen, Kristian Fog

    2008-01-01

    formation is coincident with the production of an antibiotic and a yellow-brown pigment. In this report, we demonstrate that the antibiotic is a sulfur-containing compound, tropodithietic acid (TDA). Using random transposon insertion mutagenesis, 12 genes were identified as critical for TDA biosynthesis...... by the bacteria, and mutation in any one of these results in a loss of antibiotic activity (Tda(-)) and pigment production. Unexpectedly, six of the genes, referred to as tdaA-F, could not be found on the annotated TM1040 genome and were instead located on a previously unidentified plasmid (ca. 130 kb; pSTM3...

  1. Surface roughness of composite resins subjected to hydrochloric acid.

    Science.gov (United States)

    Roque, Ana Carolina Cabral; Bohner, Lauren Oliveira Lima; de Godoi, Ana Paula Terossi; Colucci, Vivian; Corona, Silmara Aparecida Milori; Catirse, Alma Blásida Concepción Elizaur Benitez

    2015-01-01

    The purpose of this study was to determine the influence of hydrochloric acid on surface roughness of composite resins subjected to brushing. Sixty samples measuring 2 mm thick x 6 mm diameter were prepared and used as experimental units. The study presented a 3x2 factorial design, in which the factors were composite resin (n=20), at 3 levels: microhybrid composite (Z100), nanofilled composite (FiltekTM Supreme), nanohybrid composite (Ice), and acid challenge (n=10) at 2 levels: absence and presence. Acid challenge was performed by immersion of specimens in hydrochloric acid (pH 1.2) for 1 min, 4 times per day for 7 days. The specimens not subjected to acid challenge were stored in 15 mL of artificial saliva at 37 oC. Afterwards, all specimens were submitted to abrasive challenge by a brushing cycle performed with a 200 g weight at a speed of 356 rpm, totaling 17.8 cycles. Surface roughness measurements (Ra) were performed and analyzed by ANOVA and Tukey test (p≤0.05). Surface roughness values were higher in the presence (1.07±0.24) as compared with the absence of hydrochloric acid (0.72±0.04). Surface roughness values were higher for microhybrid (1.01±0.27) compared with nanofilled (0.68 ±0.09) and nanohybrid (0.48±0.15) composites when the specimens were not subjects to acid challenge. In the presence of hydrochloric acid, microhybrid (1.26±0.28) and nanofilled (1.18±0,30) composites presents higher surface roughness values compared with nanohybrid (0.77±0.15). The hydrochloric acid affected the surface roughness of composite resin subjected to brushing.

  2. Biosynthesis of highly unsaturated fatty acids by hydrocarbon degrading microorganisms

    Directory of Open Access Journals (Sweden)

    MEHDI GHASEMI

    2015-04-01

    Full Text Available Disruption of polyunsaturated fatty acids (PUFA metabolism leads to many diseases. In this study, producers of γ-linolenic acid (GLA, arachidonic acid (ARA and eicosapentaenoic acid (EPA were selected: Cephalosporium humicola IE (on glucose, dry biomass – 14 g/l, total lipids – 18-20%, GLA in lipids – 12.0%, Mucor globosus 11 (respectively – 15 g/l, 18% and 5% and Pythium irregulare LX (on glucose, dry biomass – 14.5 g/l, total lipids – 18-20%, 9.2 and 7.8% of ARA and EPA, respectively. On crude oil as the only source of carbon, the amount of biomass of the specified fungi decreases by 3-4 times, whereas the quantity of lipids and highly unsaturated fatty acids increases in four and 1.2 - 3.4 times, respectively. The maximum γ-linolenic acid in M. globosus and C. humicola was detected at neutral рН. Optimum volume of inoculate was 2.0-4.0%, nitrogen source NH4NO3, a carbon-nitrogen ratio 34:1. For biosynthesis of ARA and EPA by P. irregulare, the optimum nitrogen source was NH4Cl, рН 7.0- 8.0 and С/N - 50:1 at 28°C. The process of adaptation to stressful situation under crude oil motivated the increase of the rate of membrane phospholipids with high quantity of unsaturated fatty acids.

  3. Comparison of XAD macroporous resins for the concentration of fulvic acid from aqueous solution

    Science.gov (United States)

    Aiken, G.R.

    1979-01-01

    Five macroreticular, nonlonlc AmberlHe XAD resins were evaluated for concentration and Isolation of fulvlc acid from aqueous solution. The capacity of each resin for fulvlc acid was measured by both batch and column techniques. Elution efficiencies were determined by desorptlon with 0.1 N NaOH. Highest recoveries were obtained with the acrylic ester resins which proved to be most efficient for both adsorption and elution of fulvlc acid. Compared to the acrylic ester resins, usefulness of the styrene dvlnybenzene resins to remove fulvlc acid is limited because of slow diffusion-controlled adsorption and formation of charge-transfer complexes, which hinders elution. ?? 1979 American Chemical Society.

  4. Effect of low temperature on highly unsaturated fatty acid biosynthesis in activated sludge.

    Science.gov (United States)

    He, Su; Ding, Li-Li; Xu, Ke; Geng, Jin-Ju; Ren, Hong-Qiang

    2016-07-01

    Low temperature is a limiting factor for the microbial activity of activated sludge for sewage treatment plant in winter. Highly unsaturated fatty acid (UFA) biosynthesis, phospholipid fatty acid (PLFA) constituents and microbial structure in activated sludge at low temperature were investigated. Over 12 gigabases of metagenomic sequence data were generated with the Illumina HiSeq 2000 platform. The result showed 43.11% of phospholipid fatty acid (PLFA) in the activated sludge participated in UFA biosynthesis, and γ-Linolenic could be converted to Arachidonic acid at low temperature. The highly UFA biosynthesis in activated sludge was n-6 highly UFA biosynthesis, rather than n-3 highly UFA biosynthesis. The microbial community structures of activated sludge were analyzed by PLFA and high-throughput sequencing (HiSeq) simultaneously. Acidovorax, Pseudomonas, Flavobacterium and Polaromonas occupied higher percentage at 5°C, and genetic changes of highly UFA biosynthesis derived from microbial community structures change. Copyright © 2016. Published by Elsevier Ltd.

  5. Gamma-aminobutyric acid mediates nicotine biosynthesis in tobacco under flooding stress

    Directory of Open Access Journals (Sweden)

    Xiaoming Zhang

    2016-02-01

    Full Text Available Gamma-aminobutyric acid (GABA is a four-carbon non-protein amino acid conserved from bacteria to plants and vertebrates. Increasing evidence supports a regulatory role for GABA in plant development and the plant's response to environmental stress. The biosynthesis of nicotine, the main economically important metabolite in tobacco, is tightly regulated. GABA has not hitherto been reported to function in nicotine biosynthesis. Here we report that water flooding treatment (hypoxia markedly induced the accumulation of GABA and stimulated nicotine biosynthesis. Suppressing GABA accumulation by treatment with glutamate decarboxylase inhibitor impaired flooding-induced nicotine biosynthesis, while exogenous GABA application directly induced nicotine biosynthesis. Based on these results, we propose that GABA triggers nicotine biosynthesis in tobacco seedlings subjected to flooding. Our results provide insight into the molecular mechanism of nicotine biosynthesis in tobacco plants exposed to environmental stress.

  6. Removal of dyes from water using crosslinked aminomethane sulfonic acid based resin.

    Science.gov (United States)

    Kaner, Damla; Saraç, Ayfer; Senkal, Bahire Filiz

    2010-08-01

    A new polymeric resin with amino sulfonic acid pendant functions has been prepared for the extraction of acidic and basic dyes from water. Beaded polymer supports were prepared by suspension polymerization of vinyl benzyl chloride (0.9 mol) and ethylene glycol dimethacrylate (0.1 mol). The resulting copolymer beads were modified with amino methane sulfonic acid. The dye adsorption capacity of the resin was found as 0.16 g dye/g resin for ramazol black and 0.15 g dye/g resin for crystal violet. The pH depending measurements and dye sorption kinetics of the resin were also investigated.

  7. Oxidation-resistant acidic resins prepared by partial carbonization as cocatalysts in synthesis of adipic acid.

    Science.gov (United States)

    Wei, Huijuan; Li, Hongbian; Liu, Yangqing; Jin, Peng; Wang, Xiangyu; Li, Baojun

    2012-08-01

    The oxidation-resistant acidic resins are of great importance for the catalytic oxidation systems. In this paper, the oxidatively stable acidic resins are obtained from the cation ion exchange resins (CIERs) through the thermal treatment in N(2) atmosphere. The structure and properties of the thermally treated CIERs were characterized by chemical analysis, Fourier transform infrared (FT-IR) spectra, acid capacity measurement and scanning electron microscope (SEM). The thermally treated CIERs possess high acid capacity up to 4.09 mmol g(-1). A partial carbonization is observed in the thermal treatment process of CIERs, but the morphology of resin spheres maintains well. The as-prepared CIERs are used as solid acids to assist the hydrogen peroxide oxidation of cyclohexene to adipic acid (ADA) with tungstic acid as the catalyst precursor. The improved yields of ADA in the recycling reaction are obtained in the presence of acidic CIERs. Meanwhile, the unproductive decomposition of H(2)O(2) is effectively suppressed. The high yields of ADA (about 81%) are kept by the thermally treated CIERs even after the fifth cycle. The thermally treated CIERs exhibit excellent acid-catalytic performance and possess remarkable oxidation-resistant capability.

  8. Biosynthesis of 2-hydroxyisobutyric acid (2-HIBA from renewable carbon

    Directory of Open Access Journals (Sweden)

    Müller Roland H

    2010-02-01

    Full Text Available Abstract Nowadays a growing demand for green chemicals and cleantech solutions is motivating the industry to strive for biobased building blocks. We have identified the tertiary carbon atom-containing 2-hydroxyisobutyric acid (2-HIBA as an interesting building block for polymer synthesis. Starting from this carboxylic acid, practically all compounds possessing the isobutane structure are accessible by simple chemical conversions, e. g. the commodity methacrylic acid as well as isobutylene glycol and oxide. During recent years, biotechnological routes to 2-HIBA acid have been proposed and significant progress in elucidating the underlying biochemistry has been made. Besides biohydrolysis and biooxidation, now a bioisomerization reaction can be employed, converting the common metabolite 3-hydroxybutyric acid to 2-HIBA by a novel cobalamin-dependent CoA-carbonyl mutase. The latter reaction has recently been discovered in the course of elucidating the degradation pathway of the groundwater pollutant methyl tert-butyl ether (MTBE in the new bacterial species Aquincola tertiaricarbonis. This discovery opens the ground for developing a completely biotechnological process for producing 2-HIBA. The mutase enzyme has to be active in a suitable biological system producing 3-hydroxybutyryl-CoA, which is the precursor of the well-known bacterial bioplastic polyhydroxybutyrate (PHB. This connection to the PHB metabolism is a great advantage as its underlying biochemistry and physiology is well understood and can easily be adopted towards producing 2-HIBA. This review highlights the potential of these discoveries for a large-scale 2-HIBA biosynthesis from renewable carbon, replacing conventional chemistry as synthesis route and petrochemicals as carbon source.

  9. Biosynthesis of 2-hydroxyisobutyric acid (2-HIBA) from renewable carbon.

    Science.gov (United States)

    Rohwerder, Thore; Müller, Roland H

    2010-02-25

    Nowadays a growing demand for green chemicals and cleantech solutions is motivating the industry to strive for biobased building blocks. We have identified the tertiary carbon atom-containing 2-hydroxyisobutyric acid (2-HIBA) as an interesting building block for polymer synthesis. Starting from this carboxylic acid, practically all compounds possessing the isobutane structure are accessible by simple chemical conversions, e. g. the commodity methacrylic acid as well as isobutylene glycol and oxide. During recent years, biotechnological routes to 2-HIBA acid have been proposed and significant progress in elucidating the underlying biochemistry has been made. Besides biohydrolysis and biooxidation, now a bioisomerization reaction can be employed, converting the common metabolite 3-hydroxybutyric acid to 2-HIBA by a novel cobalamin-dependent CoA-carbonyl mutase. The latter reaction has recently been discovered in the course of elucidating the degradation pathway of the groundwater pollutant methyl tert-butyl ether (MTBE) in the new bacterial species Aquincola tertiaricarbonis. This discovery opens the ground for developing a completely biotechnological process for producing 2-HIBA. The mutase enzyme has to be active in a suitable biological system producing 3-hydroxybutyryl-CoA, which is the precursor of the well-known bacterial bioplastic polyhydroxybutyrate (PHB). This connection to the PHB metabolism is a great advantage as its underlying biochemistry and physiology is well understood and can easily be adopted towards producing 2-HIBA. This review highlights the potential of these discoveries for a large-scale 2-HIBA biosynthesis from renewable carbon, replacing conventional chemistry as synthesis route and petrochemicals as carbon source.

  10. Proteolytic Pathways Induced by Herbicides That Inhibit Amino Acid Biosynthesis

    Science.gov (United States)

    Zulet, Amaia; Gil-Monreal, Miriam; Villamor, Joji Grace; Zabalza, Ana; van der Hoorn, Renier A. L.; Royuela, Mercedes

    2013-01-01

    Background The herbicides glyphosate (Gly) and imazamox (Imx) inhibit the biosynthesis of aromatic and branched-chain amino acids, respectively. Although these herbicides inhibit different pathways, they have been reported to show several common physiological effects in their modes of action, such as increasing free amino acid contents and decreasing soluble protein contents. To investigate proteolytic activities upon treatment with Gly and Imx, pea plants grown in hydroponic culture were treated with Imx or Gly, and the proteolytic profile of the roots was evaluated through fluorogenic kinetic assays and activity-based protein profiling. Results Several common changes in proteolytic activity were detected following Gly and Imx treatment. Both herbicides induced the ubiquitin-26 S proteasome system and papain-like cysteine proteases. In contrast, the activities of vacuolar processing enzymes, cysteine proteases and metacaspase 9 were reduced following treatment with both herbicides. Moreover, the activities of several putative serine protease were similarly increased or decreased following treatment with both herbicides. In contrast, an increase in YVADase activity was observed under Imx treatment versus a decrease under Gly treatment. Conclusion These results suggest that several proteolytic pathways are responsible for protein degradation upon herbicide treatment, although the specific role of each proteolytic activity remains to be determined. PMID:24040092

  11. NGF blocks polyunsaturated fatty acids biosynthesis in n-3 fatty acid-supplemented PC12 cells.

    Science.gov (United States)

    Msika, Ora; Brand, Annette; Crawford, Michael A; Yavin, Ephraim

    2012-07-01

    Regulation of polyunsaturated fatty acid (PUFA) biosynthesis in proliferating and NGF-differentiated PC12 pheochromocytoma cells deficient in n-3 docosahexaenoic acid (DHA 22:6n-3) was studied. A dose- and time-dependent increase in eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3) and DHA in phosphatidylethanolamine (PtdEtn) and phosphatidylserine (PtdSer) glycerophospholipids (GPL) via the elongation/desaturation pathway following alpha-linolenic acid (ALA, 18:3n-3) supplements was observed. That was accompanied by a marked reduction of eicosatrienoic acid (Mead acid 20:3n-9), an index of PUFA deficiency. EPA supplements were equally effective converted to 22:5n-3 and 22:6n-3. On the other hand, supplements of linoleic acid (LNA, 18:2n-6) were not effectively converted into higher n-6 PUFA intermediates nor did they impair elongation/desaturation of ALA. Co-supplements of DHA along with ALA did not interfere with 20:5n-3 biosynthesis but reduced further elongation to 22-hydrocarbon PUFA intermediates. A marked decrease in the newly synthesized 22:5n-3 and 22:6n-3 following ALA or EPA supplements was observed after nerve growth factor (NGF)-induced differentiation. NGF also inhibited the last step in 22:5n-6 formation from LNA. These results emphasize the importance of overcoming n-3 PUFA deficiency and raise the possibility that growth factor regulation of the last step in PUFA biosynthesis may constitute an important feature of neuronal phenotype acquisition. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Biosynthesis of Alkyl Lysophosphatidic Acid by Diacylglycerol Kinases

    Science.gov (United States)

    Gellett, Amanda M.; Kharel, Yugesh; Sunkara, Manjula; Morris, Andrew J.; Lynch, Kevin R.

    2012-01-01

    Lysophosphatidic acid (LPA) designates a family of bioactive phosphoglycerides that differ in the length and degree of saturation of their radyl chain. Additional diversity is provided by the linkage of the radyl chain to glycerol: acyl, alkyl, or alk-1-enyl. Acyl-LPAs are the predominate species in tissues and biological fluids. Alkyl-LPAs exhibit distinct pharmacodynamics at LPA receptors, potently drive platelet aggregation, and contribute to ovarian cancer aggressiveness. Multiple biosynthetic pathways exist for alkyl-LPA production. Herein we report that diacylglycerol kinases (DGKs) contribute to cell-associated alkyl-LPA production involving phosphorylation of 1-alkyl-2-acetyl glycerol and document the biosynthesis of alkyl-LPA by DGKs in SKOV-3 ovarian cancer cells, specifically identifying the contribution of DGKα. Concurrently, we discovered that treating SKOV-3 ovarian cancer cell with a sphingosine analog stimulates conversion of exogenous 1-alkyl-2-acetyl glycerol to alkyl-LPA, indicating that DGKα contributes significantly to the production of alkyl-LPA in SKOV-3 cells and identifying cross-talk between the sphingolipid and glycerol lipid pathways. PMID:22627129

  13. Alkene hydrogenation activity of enoate reductases for an environmentally benign biosynthesis of adipic acid.

    Science.gov (United States)

    Joo, Jeong Chan; Khusnutdinova, Anna N; Flick, Robert; Kim, Taeho; Bornscheuer, Uwe T; Yakunin, Alexander F; Mahadevan, Radhakrishnan

    2017-02-01

    Adipic acid, a precursor for Nylon-6,6 polymer, is one of the most important commodity chemicals, which is currently produced from petroleum. The biosynthesis of adipic acid from glucose still remains challenging due to the absence of biocatalysts required for the hydrogenation of unsaturated six-carbon dicarboxylic acids to adipic acid. Here, we demonstrate the first enzymatic hydrogenation of 2-hexenedioic acid and muconic acid to adipic acid using enoate reductases (ERs). ERs can hydrogenate 2-hexenedioic acid and muconic acid producing adipic acid with a high conversion rate and yield in vivo and in vitro . Purified ERs exhibit a broad substrate spectrum including aromatic and aliphatic 2-enoates and a significant oxygen tolerance. The discovery of the hydrogenation activity of ERs contributes to an understanding of the catalytic mechanism of these poorly characterized enzymes and enables the environmentally benign biosynthesis of adipic acid and other chemicals from renewable resources.

  14. Oxidation of resin acids in colophony (rosin) and its implications for patch testing.

    Science.gov (United States)

    Sadhra, S; Foulds, I S; Gray, C N

    1998-08-01

    Commercial preparations of colophony (rosin) used for patch testing are made from unmodified rosin in pet. and may be stored for some considerable time before being used. This would be satisfactory if the composition and dermatological activity of the preparations were both reproducible and stable, but investigations by the authors have shown that the resin acids undergo progressive and substantial oxidation and that the dermatological activity of the preparations increases significantly with time. This may be a cause of inconsistent patch test results unless the composition can be stabilized. Gas liquid chromatography (GLC) analysis of a raw rosin sample and its commercial patch test preparation has shown that they both contained the same resin acids, but the concentration of the abietic type resin acids was found to be lower in the patch test preparations. The degradation of resin acids is due to their atmospheric oxidation, which may occur during the preparation and storage of the commercial rosin patch test preparation. The susceptibility of individual resin acids to atmospheric oxidation was demonstrated by analysing a sample of raw Portuguese gum rosin, which was then left exposed to air and light. Most of the resin acids were found to undergo oxidation at a rate which gradually diminished. More importantly, it is presumed that the concentration of oxidized resin acids increased correspondingly, and these have been shown to be more dermatologically active than the unoxidised resin acids. The rate of decrease of resin acid concentration was found to be in the following order: neoabietic>levopimaric and palustric>abietic>dehydroabetic acid. The pimaric type resin acids were found to be relatively inert to atmospheric oxidation when compared with the abietic type resin acids. Patch testing with the resulting partly oxidized Portuguese rosin produced positive reactions at a 35% higher frequency than the raw Portuguese rosin. The study demonstrates that the

  15. Usage of methyl ester of tall oil fatty acids and resinic acids as alternative diesel fuel

    International Nuclear Information System (INIS)

    Keskin, Ali; Yasar, Abdulkadir; Guerue, Metin; Altiparmak, Duran

    2010-01-01

    In the experimental study, tall oil fatty and resinic acids were investigated as alternative diesel fuels. The fatty acids, obtained by distilling the crude tall oil, were esterified with methanol in order to obtain tall oil methyl ester (biodiesel). Blends of the methyl ester, resinic acids and diesel fuel were prepared for test fuels. Performance and emission tests of the test fuels were carried out in an unmodified direct injection diesel engine on full load conditions. The results showed that the specific fuel consumption (SFC) with the blend fuels did not show a significant change. CO emission and smoke level decreased up to 23.91% and 19.40%, respectively. In general, NO x emissions showed on trend of increasing with the blend fuels (up to 25.42%). CO 2 emissions did not vary with the blend fuels significantly.

  16. Usage of methyl ester of tall oil fatty acids and resinic acids as alternative diesel fuel

    Energy Technology Data Exchange (ETDEWEB)

    Keskin, Ali; Yasar, Abdulkadir [Tarsus Technical Education Faculty, Mersin University, 33500 Mersin (Turkey); Guerue, Metin [Engineering and Architectural Faculty, Gazi University, 06570 Maltepe, Ankara (Turkey); Altiparmak, Duran [Technical Education Faculty, Gazi University, 06500 Ankara (Turkey)

    2010-12-15

    In the experimental study, tall oil fatty and resinic acids were investigated as alternative diesel fuels. The fatty acids, obtained by distilling the crude tall oil, were esterified with methanol in order to obtain tall oil methyl ester (biodiesel). Blends of the methyl ester, resinic acids and diesel fuel were prepared for test fuels. Performance and emission tests of the test fuels were carried out in an unmodified direct injection diesel engine on full load conditions. The results showed that the specific fuel consumption (SFC) with the blend fuels did not show a significant change. CO emission and smoke level decreased up to 23.91% and 19.40%, respectively. In general, NO{sub x} emissions showed on trend of increasing with the blend fuels (up to 25.42%). CO{sub 2} emissions did not vary with the blend fuels significantly. (author)

  17. Chlorogenic acids and the acyl-quinic acids: discovery, biosynthesis, bioavailability and bioactivity.

    Science.gov (United States)

    Clifford, Michael N; Jaganath, Indu B; Ludwig, Iziar A; Crozier, Alan

    2017-12-13

    Covering: 2000 up to late 2017This review is focussed upon the acyl-quinic acids, the most studied group within the ca. 400 chlorogenic acids so far reported. The acyl-quinic acids, the first of which was characterised in 1846, are a diverse group of plant-derived compounds produced principally through esterification of an hydroxycinnamic acid and 1l-(-)-quinic acid. Topics addressed in this review include the confusing nomenclature, quantification and characterisation by NMR and MS, biosynthesis and role in planta, and the occurrence of acyl-quinic acids in coffee, their transformation during roasting and delivery to the beverage. Coffee is the major human dietary source world-wide of acyl-quinic acids and consideration is given to their absorption and metabolism in the upper gastrointestinal tract, and the colon where the microbiota play a key role in the formation of catabolites. Evidence on the potential of the in vivo metabolites and catabolites of acyl-quinic acids to promote the consumer's health is evaluated.

  18. Phosphate limitation promotes unsaturated fatty acids and arachidonic acid biosynthesis by microalgae Porphyridium purpureum.

    Science.gov (United States)

    Su, Gaomin; Jiao, Kailin; Li, Zheng; Guo, Xiaoyi; Chang, Jingyu; Ndikubwimana, Theoneste; Sun, Yong; Zeng, Xianhai; Lu, Yinghua; Lin, Lu

    2016-07-01

    Polyunsaturated fatty acids (PUFAs) are highly appreciated on their nutritive value for human health and aquaculture. P. purpureum, one of the red microalgae acknowledged as a promising accumulator of ARA, was chosen as the target algae in the present research. Effects of sodium bicarbonate (0.04-1.2 g/L), temperature (25, 30 and 33 °C) and phosphate (0.00-0.14 g/L) on biomass yield, total fatty acids (TFA) and arachidonic acid (ARA) accumulation were investigated systemically. NaHCO3 dose of 0.8 g/L and moderate temperature of 30 °C were preferred. In addition, TFA and ARA production were significantly enhanced by an appropriate concentration of phosphate, and the highest TFA yield of 666.38 mg/L and ARA yield of 159.74 mg/L were obtained at a phosphate concentration of 0.035 g/L. Interestingly, with phosphate concentration continuing to fall, UFA/TFA and ARA/EPA ratios were increased accordingly, suggesting that phosphate limitation promoted unsaturated fatty acids and arachidonic acid biosynthesis. Low concentration of phosphate may be favored to increase the enzymatic activities of ∆6-desaturase, which played a key role in catalyzing the conversion of C16:0 to C18:2, and thus the selectivity of UFA increased. Meanwhile, the increase of ARA selectivity could be attributed to ω6 pathway promotion and ∆17-desaturase activity inhibition with phosphate limitation. Phosphate limitation strategy enhanced unsaturated fatty acids and ARA biosynthesis in P. purpureum, and can be applied in commercial scale manufacturing and commercialization of ARA.

  19. Studies concerning the anion ex-change resins catalyzed esterification of epichlorohydrin with organic acids

    Directory of Open Access Journals (Sweden)

    E.I. Muresan

    2009-09-01

    Full Text Available The paper studies the esterification of carboxylic acids with epichlorohydrin over two macroporous strong base anion exchange resins with different polymer matrix. For both resins, the influence of reaction parameters (temperature, catalyst loading, molar ratio on the reaction rate and the yields of the two isomeric esters were investigated.

  20. Development of melamine modified urea formaldehyde resins based o nstrong acidic pH catalyzed urea formaldehyde polymer

    Science.gov (United States)

    Chung-Yun Hse

    2009-01-01

    To upgrade the performance of urea-formaldehyde (UF) resin bonded particleboards, melamine modified urea-formaldehyde (MUF) resins based on strong acidic pH catalyzed UF polymers were investigated. The study was conducted in a series of two experiments: 1) formulation of MUF resins based on a UF polymer catalyzed with strong acidic pH and 2) determination of the...

  1. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    KAUST Repository

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  2. A model of proteolysis and amino acid biosynthesis for Lactobacillus delbrueckii subsp. bulgaricus in whey.

    Science.gov (United States)

    Liu, Enuo; Zheng, Huajun; Hao, Pei; Konno, Tomonobu; Yu, Yao; Kume, Hisae; Oda, Munehiro; Ji, Zai-Si

    2012-12-01

    Lactobacillus delbrueckii subsp. bulgaricus 2038 (L. bulgaricus 2038) is a bacterium that is used as a starter for dairy products by Meiji Co., Ltd of Japan. Culturing L. bulgaricus 2038 with whey as the sole nitrogen source results in a shorter lag phase than other milk proteins under the same conditions (carbon source, minerals, and vitamins). Microarray results of gene expression revealed characteristics of amino acid anabolism with whey as the nitrogen source and established a model of proteolysis and amino acid biosynthesis for L. bulgaricus. Whey peptides and free amino acids are readily metabolized, enabling rapid entry into the logarithmic growth phase. The oligopeptide transport system is the primary pathway for obtaining amino acids. Amino acid biosynthesis maintains the balance between amino acids required for cell growth and the amount obtained from environment. The interconversion of amino acids is also important for L. bulgaricus 2038 growth.

  3. Separation of chlorogenic acid from honeysuckle crude extracts by macroporous resins.

    Science.gov (United States)

    Zhang, Bin; Yang, Ruiyuan; Zhao, Yan; Liu, Chun-Zhao

    2008-05-15

    Chlorogenic acid, one of the most bioactive compounds rich in the Chinese medicinal herb honeysuckle, is a natural antioxidant and serves as anti-inflammatory, anti-tumor, anti-mutagenic and anti-carcinogenic agent. An efficient preparative separation process of chlorogenic acid from honeysuckle crude extracts has been developed in the present study. HPD-850 resin offers the best adsorption capacity, and adsorption and desorption ratios for chlorogenic acid among the nine macroporous resins tested, and its adsorption rate at 25 degrees C fit best to the Langmuir isotherm. The adsorption capacity of HPD-850 resin was found to depend strongly on the pH value of the initial adsorption solution. The dynamic adsorption and desorption experiments have been carried out on a HPD-850 resin packed column to optimize the separation process of chlorogenic acid from honeysuckle crude extracts. After one run treatment with HPD-850 resin, the chlorogenic acid content in the final product was increased 4.46-fold from 11.2% to 50.0%, with a recovery yield of 87.9%. The preparative separation of chlorogenic acid can be easily and efficiently achieved via adsorption and desorption on HPD-850 resin, and the method developed will provide a potential approach for large-scale separation and purification of chlorogenic acid for its wide pharmaceutical use.

  4. Industrial alkyd resins: characterization of pentaerythritol and phthalic acid esters using integrated mass spectrometry.

    Science.gov (United States)

    La Nasa, Jacopo; Degano, Ilaria; Modugno, Francesca; Colombini, Maria Perla

    2015-02-15

    Alkyd resins are synthetic polyesters used as paints and coatings. Current approaches for their analysis do not allow the characterization of pentaerythritol and phthalic acid esters, whose detection is interesting to fully characterize the materials, e.g. for forensic or cultural heritage applications. A combined analytical approach based on Gas Chromatography/Mass Spectrometry (GC/MS), High-Performance Liquid Chromatography (HPLC)/MS and flow injection analysis (FIA)/MS was adopted. GC/MS was used to characterize the fatty acid profile and the polybasic acids in extracts from industrial alkyd resins. HPLC/MS and FIA/MS were used for the characterization of the triglyceride profile of the oil used to manufacture the resin and for the identification of reaction products deriving from the synthesis process. The multi-analytical approach was applied on two different industrial alkyd resins produced from two different oils. The GC/MS analysis was successful in characterizing the fatty acid profile and the aromatic fraction of the resin. The HPLC/MS analysis allowed us to characterize the pentaerythritol and phthalic acid ester and the triglycerides residues from the synthesis process, by studying their high-resolution tandem mass spectra. The application of liquid chromatography coupled with high-resolution tandem mass spectrometry to the study of industrial alkyd resins allowed us to characterize for the first time the esters formed by the transesterification reactions involving pentaerythritol, phthalic acid and triglycerides. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Effect of alpha-linolenic, capric and lauric acid on the fatty acid biosynthesis in Staphylococcus aureus.

    Science.gov (United States)

    Sado-Kamdem, Sylvain L; Vannini, Lucia; Guerzoni, M Elisabetta

    2009-02-28

    The antimicrobial activity of alpha-linolenic, capric and lauric acids on Staphylococcus aureus was studied in relation to their effect on the de novo fatty acid biosynthesis. Labelled acetate was used as integrated carbon source and traced in the de novo fatty acid by using a GC-Mass spectrometer and the single ion monitoring (SIM) technique. The detection of the incorporation of the labelled carbon into the individual cell fatty acids (FAs) provided an insight into the different effects of alpha-linolenic, capric and lauric acids on the FA biosynthesis. The results suggested that FAs pathway is the major target of alpha-linolenic acid and that other enzymes in addition to FabI are involved in S. aureus response mechanism when medium chain fatty acids are present.

  6. Autoxidated linolenic acid inhibits aflatoxin biosynthesis in Aspergillus flavus via oxylipin species.

    Science.gov (United States)

    Yan, Shijuan; Liang, Yating; Zhang, Jindan; Chen, Zhuang; Liu, Chun-Ming

    2015-08-01

    Aflatoxins produced by Aspergillus species are among the most toxic and carcinogenic compounds in nature. Although it has been known for a long time that seeds with high oil content are more susceptible to aflatoxin contamination, the role of fatty acids in aflatoxin biosynthesis remains controversial. Here we demonstrate in A. flavus that both the saturated stearic acid (C18:0) and the polyunsaturated linolenic acid (C18:3) promoted aflatoxin production, while C18:3, but not C18:0, inhibited aflatoxin biosynthesis after exposure to air for several hours. Further experiments showed that autoxidated C18:3 promoted mycelial growth, sporulation, and kojic acid production, but inhibited the expression of genes in the AF biosynthetic gene cluster. Mass spectrometry analyses of autoxidated C18:3 fractions that were able to inhibit aflatoxin biosynthesis led to the identification of multiple oxylipin species. These results may help to clarify the role of fatty acids in aflatoxin biosynthesis, and may explain why controversial results have been obtained for fatty acids in the past. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Induced oleoresin biosynthesis in grand fir as a defense against bark beetles.

    OpenAIRE

    Steele, C L; Lewinsohn, E; Croteau, R

    1995-01-01

    Grand fir (Abies grandis) saplings and derived cell cultures are useful systems for studying the regulation of defensive oleoresinosis in conifers, a process involving both the constitutive accumulation of resin (pitch) in specialized secretory structures and the induced production of monoterpene olefins (turpentine) and diterpene resin acids (rosin) by nonspecialized cells at the site of injury. The pathways and enzymes involved in monoterpene and diterpene resin acid biosynthesis are descri...

  8. (Methacrylic Acid-Co-Divinylbenzene) Resin as Filler

    African Journals Online (AJOL)

    divinylbenzene) resin (PMD) as a new filler-binder for direct compression tablets. Methods: Powder properties of PMD and MCC were characterized. Tablets made from PMD and MCC with and without propranolol hydrochloride were evaluated for ...

  9. Polyunsaturated fatty acids influence differential biosynthesis of oxylipids and other lipid mediators during bovine coliform mastitis.

    Science.gov (United States)

    Mavangira, Vengai; Gandy, Jeffery C; Zhang, Chen; Ryman, Valerie E; Daniel Jones, A; Sordillo, Lorraine M

    2015-09-01

    Coliform mastitis is a severe and sometimes fatal disease characterized by an unregulated inflammatory response. The initiation, progression, and resolution of inflammatory responses are regulated, in part, by potent oxylipid metabolites derived from polyunsaturated fatty acids. The purpose of this study was to characterize the biosynthesis and diversity of oxylipid metabolites during acute bovine coliform mastitis. Eleven cows diagnosed with naturally occurring acute systemic coliform mastitis and 13 healthy control cows, matched for lactation number and days in milk, were selected for comparison of oxylipid and free fatty acid concentrations in both milk and plasma. Oxylipids and free fatty acids were quantified using liquid chromatography-tandem mass spectrometry. All polyunsaturated fatty acids quantified in milk were elevated during coliform mastitis with linoleic acid being the most abundant. Oxylipids synthesized through the lipoxygenase and cytochrome P450 pathways accounted for the majority of the oxylipid biosynthesis. This study demonstrated a complex and diverse oxylipid network, most pronounced at the level of the mammary gland. Substrate availability, biosynthetic pathways, and degree of metabolism influence the biosynthesis of oxylipids during bovine coliform mastitis. Further studies are required to identify targets for novel interventions that modulate oxylipid biosynthesis during coliform mastitis to optimize inflammation. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. Isolated etioplasts as test system for inhibitors of fatty acid biosynthesis

    International Nuclear Information System (INIS)

    Lichtenthaler, H.K.; Kobek, K.

    1989-01-01

    Isolated intact chloroplasts of mono- and dicotyledonous plants possess the capacity for de novo fatty acid biosynthesis, starting from 14 C-acetate. These can be taken as test system for herbicides affecting fatty acid biosynthesis as shown earlier in our laboratory. The incorporation rates of acetate into the total fatty acids depend on the photosynthetic cofactors ATP and NADPH and amount in the light to 33 kBq (oat) and 39 kBq (pea) per mg chlorophyll x h, whereas in the dark only ca. 10% of these rates are obtained. In order to establish a test system, which is fully independent of light, we isolated and characterized etioplast fractions from oat and pea seedlings with a very high capacity of de novo fatty acid biosynthesis (500 and 400 kBq per mg carotenoids in a 20 min period). This activity was blocked by herbicides such as cycloxydim, sethoxydim and diclofop in a dose-dependent manner. This new test system has the great advantage that one can verify whether inhibitors of photosynthesis affect fatty acid biosynthesis

  11. Biosynthesis of natural products containing β-amino acids.

    Science.gov (United States)

    Kudo, Fumitaka; Miyanaga, Akimasa; Eguchi, Tadashi

    2014-08-01

    Covering: up to January, 2014. We focus here on β-amino acids as components of complex natural products because the presence of β-amino acids produces structural diversity in natural products and provides characteristic architectures beyond those of ordinary α-L-amino acids, thus generating significant and unique biological functions in nature. In this review, we first survey the known bioactive β-amino acid-containing natural products including nonribosomal peptides, macrolactam polyketides, and nucleoside-β-amino acid hybrids. Next, the biosynthetic enzymes that form β-amino acids from α-amino acids and the de novo synthesis of β-amino acids are summarized. Then, the mechanisms of β-amino acid incorporation into natural products are reviewed. Because it is anticipated that the rational swapping of the β-amino acid moieties with various side chains and stereochemistries by biosynthetic engineering should lead to the creation of novel architectures and bioactive compounds, the accumulation of knowledge regarding β-amino acid-containing natural product biosynthetic machinery could have a significant impact in this field. In addition, genome mining of characteristic β-amino acid biosynthetic genes and unique β-amino acid incorporation machinery could lead to the discovery of new β-amino acid-containing natural products.

  12. Direct biosynthesis of adipic acid from a synthetic pathway in recombinant Escherichia coli.

    Science.gov (United States)

    Yu, Jia-Le; Xia, Xiao-Xia; Zhong, Jian-Jiang; Qian, Zhi-Gang

    2014-12-01

    The C6 dicarboxylic acid, adipic acid, is an important platform chemical in industry. Biobased production of adipic acid is a promising alternative to the current petrochemical route. Here, we report biosynthesis of adipic acid using an artificial pathway inspired by the reversal of beta-oxidation of dicarboxylic acids. The biosynthetic pathway comprises condensation of acetyl-CoA and succinyl-CoA to form the C6 backbone and subsequent reduction, dehydration, hydrogenation, and release of adipic acid from its thioester. The pathway was first tested in vitro with reconstituted pathway enzymes and then functionally introduced into Escherichia coli for the biosynthesis and excretion of adipic acid into the culture medium. The production titer was increased by approximately 20-fold through the combination of recruiting enzymes that were more suitable to catalyze the synthetic reactions and increasing availability of the condensation substrates. This work demonstrates direct biosynthesis of adipic acid via non-natural synthetic pathway, which may enable its renewable production. © 2014 Wiley Periodicals, Inc.

  13. The role of peroxisomal fatty acyl-CoA beta-oxidation in bile acid biosynthesis

    International Nuclear Information System (INIS)

    Hayashi, H.; Miwa, A.

    1989-01-01

    The physiological role of the peroxisomal fatty acyl-CoA beta-oxidizing system (FAOS) is not yet established. We speculated that there might be a relationship between peroxisomal degradation of long-chain fatty acids in the liver and the biosynthesis of bile acids. This was investigated using [1- 14 C]butyric acid and [1- 14 C]lignoceric acid as substrates of FAOS in mitochondria and peroxisomes, respectively. The incorporation of [ 14 C]lignoceric acid into primary bile acids was approximately four times higher than that of [ 14 C]butyric acid (in terms of C-2 units). The pools of these two fatty acids in the liver were exceedingly small. The incorporations of radioactivity into the primary bile acids were strongly inhibited by administration of aminotriazole, which is a specific inhibitor of peroxisomal FAOS in vivo. Aminotriazole inhibited preferentially the formation of cholate, the major primary bile acid, from both [ 14 C]lignoceric acid and [ 14 C]butyric acid, rather than the formation of chenodeoxycholate. The former inhibition was about 70% and the latter was approximately 40-50%. In view of reports that cholate is biosynthesized from endogenous cholesterol, the above results indicate that peroxisomal FAOS may have an anabolic function, supplying acetyl CoA for bile acid biosynthesis

  14. The role of peroxisomal fatty acyl-CoA beta-oxidation in bile acid biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, H.; Miwa, A. (Josai Univ., Saitama (Japan))

    1989-11-01

    The physiological role of the peroxisomal fatty acyl-CoA beta-oxidizing system (FAOS) is not yet established. We speculated that there might be a relationship between peroxisomal degradation of long-chain fatty acids in the liver and the biosynthesis of bile acids. This was investigated using (1-{sup 14}C)butyric acid and (1-{sup 14}C)lignoceric acid as substrates of FAOS in mitochondria and peroxisomes, respectively. The incorporation of ({sup 14}C)lignoceric acid into primary bile acids was approximately four times higher than that of ({sup 14}C)butyric acid (in terms of C-2 units). The pools of these two fatty acids in the liver were exceedingly small. The incorporations of radioactivity into the primary bile acids were strongly inhibited by administration of aminotriazole, which is a specific inhibitor of peroxisomal FAOS in vivo. Aminotriazole inhibited preferentially the formation of cholate, the major primary bile acid, from both ({sup 14}C)lignoceric acid and ({sup 14}C)butyric acid, rather than the formation of chenodeoxycholate. The former inhibition was about 70% and the latter was approximately 40-50%. In view of reports that cholate is biosynthesized from endogenous cholesterol, the above results indicate that peroxisomal FAOS may have an anabolic function, supplying acetyl CoA for bile acid biosynthesis.

  15. Biosynthesis, natural sources, dietary intake, pharmacokinetic properties, and biological activities of hydroxycinnamic acids.

    Science.gov (United States)

    El-Seedi, Hesham R; El-Said, Asmaa M A; Khalifa, Shaden A M; Göransson, Ulf; Bohlin, Lars; Borg-Karlson, Anna-Karin; Verpoorte, Rob

    2012-11-07

    Hydroxycinnamic acids are the most widely distributed phenolic acids in plants. Broadly speaking, they can be defined as compounds derived from cinnamic acid. They are present at high concentrations in many food products, including fruits, vegetables, tea, cocoa, and wine. A diet rich in hydroxycinnamic acids is thought to be associated with beneficial health effects such as a reduced risk of cardiovascular disease. The impact of hydroxycinnamic acids on health depends on their intake and pharmacokinetic properties. This review discusses their chemistry, biosynthesis, natural sources, dietary intake, and pharmacokinetic properties.

  16. Synthesis and characterization of an N-(2-hydroxyethyl)-ethylenediaminetriacetic acid resin

    International Nuclear Information System (INIS)

    Lai, Y.F.

    1977-10-01

    A chelating ion-exchange resin with N-(2-hydroxyethyl)ethylene-diaminetriacetic acid (HEDTA) used as the ligand chemically bonded to XAD-4 by an ester linkage, HEDTA-4, was synthesized. It is stable under normal experimental conditions with the liquid chromatograph. The structure of the resin was confirmed by an infrared spectrum, and by potentiometric titrations. The capacity of the resin was also obtained by potentiometric titration and by a nitrogen analysis. The resin was used to pack a column of 5 mm internal diameter and 5 cm long. The effect of pH on the retention of different metal ions on the resin was studied. It was found that the resin was most selective for chromium(III), copper(II), lead(II), mercury(II), uranium(VI), zirconium(IV) and zinc(II) at a pH of less than 3. Furthermore, the resin proves to be functioning with a chelating mechanism rather than ion-exchange, and it can concentrate trace metal ions in the presence of a large excess of calcium and magnesium. This makes the resin potentially useful for purifying and analyzing drinking water

  17. Characterization of the role of para-aminobenzoic acid biosynthesis in folate production by Lactococcus lactis

    NARCIS (Netherlands)

    Wegkamp, H.B.A.; Oorschot, van A.; Vos, de W.M.; Smid, E.J.

    2007-01-01

    The pab genes for para-aminobenzoic acid (pABA) biosynthesis in Lactococcus lactis were identified and characterized. In L. lactis NZ9000, only two of the three genes needed for pABA production were initially found. No gene coding for 4-amino-4-deoxychorismate lyase (pabC) was initially annotated,

  18. Stimulatory effects of acibenzolar-s-methyl on chlorogenic acids biosynthesis in Centella asiatica cells

    CSIR Research Space (South Africa)

    Ncube, EN

    2016-09-01

    Full Text Available -derived chlorogenic acids (CGAs) that have recently been reported to confer neuroprotective properties. In a biotechnological attempt to increase the biosynthesis of CGA-derivatives in cultured Centella cells, acibenzolar-S-methyl was applied as a xenobiotic inducer...

  19. Identification of the orsellinic acid synthase PKS63787 for the biosynthesis of antroquinonols in Antrodia cinnamomea.

    Science.gov (United States)

    Yu, Po-Wei; Cho, Ting-Yu; Liou, Ruey-Fen; Tzean, Shean-Shong; Lee, Tzong-Huei

    2017-06-01

    Antrodia cinnamomea, an endemic basidiomycete used as a health food in Taiwan, is known to synthesize antroquinonols, which were reported to have notable medicinal potential in oncology and immunology. However, the biosynthetic pathway of these compounds is currently unclear. Our previous study showed that a pks63787 knockout mutant of A. cinnamomea (∆pks63787) is deficient in the biosynthesis of several aromatic metabolites. In this study, we pointed by phylogenetic analysis that pks63787 likely encodes an orsellinic acid synthase. Moreover, amendment of the cultural medium with orsellinic acid not only restores the ability of ∆pks63787 to produce its major pigment and other deficient metabolites, e.g., antroquinonols, but also enhances the productivity of several antroquinonols, including two new compounds 2 and 3. These results provide direct evidence that the PKS63787 is involved in the biosynthesis of antroquinonols and confirmed our hypothesis that the 6-methylcyclohexenone moiety was synthesized via the PKS63787-mediated polyketide pathway. In conclusion, PKS63787 might function as orsellinic acid synthase and orsellinic acid is an important precursor indispensable for the biosynthesis of the major pigment and antroquinonols in A. cinnamomea. To facilitate further basic or applied study, a putative biosynthesis pathway map of antroquinonols is proposed.

  20. Regulation of aromatic amino acid biosynthesis in the ribulose monophosphate cycle methylotroph Nocardia sp. 239

    NARCIS (Netherlands)

    Boer, L. de; Vrijbloed, J.W.; Grobben, G.; Dijkhuizen, L.

    The regulation of aromatic amino acid biosynthesis in Nocardia sp. 239 was studied. In cell-free extracts 3-deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase activity was inhibited in a cumulative manner by tryptophan, phenylalanine and tyrosine. Chorismate mutase was inhibited by both

  1. Stress -induced biosynthesis of dicaffeoylquinic acids in globe artichoke

    NARCIS (Netherlands)

    Moglia, A.; Lanteri, S.; Comino, C.; Acquadro, A.; Vos, de C.H.; Beekwilder, M.J.

    2008-01-01

    Leaf extracts from globe artichoke (Cynara cardunculus L. var. scolymus) have been widely used in medicine as hepatoprotectant and choleretic agents. Globe artichoke leaves represent a natural source of phenolic acids with dicaffeoylquinic acids, such as cynarin (1,3-dicaffeoylquinic acid), along

  2. Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics.

    Directory of Open Access Journals (Sweden)

    Morgan N Price

    2018-01-01

    Full Text Available For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. We studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fill 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.

  3. Competition between ethanol clearance and retinoic acid biosynthesis in the induction of fetal alcohol syndrome.

    Science.gov (United States)

    Shabtai, Yehuda; Fainsod, Abraham

    2018-04-01

    Several models have been proposed to explain the neurodevelopmental syndrome induced by exposure of human embryos to alcohol, which is known as fetal alcohol spectrum disorder (FASD). One of the proposed models suggests a competition for the enzymes required for the biosynthesis of retinoic acid. The outcome of such competition is development under conditions of reduced retinoic acid signaling. Retinoic acid is one of the biologically active metabolites of vitamin A (retinol), and regulates numerous embryonic and differentiation processes. The developmental malformations characteristic of FASD resemble those observed in vitamin A deficiency syndrome as well as from inhibition of retinoic acid biosynthesis or signaling in experimental models. There is extensive biochemical and enzymatic overlap between ethanol clearance and retinoic acid biosynthesis. Several lines of evidence suggest that in the embryo, the competition takes place between acetaldehyde and retinaldehyde for the aldehyde dehydrogenase activity available. In adults, this competition also extends to the alcohol dehydrogenase activity. Ethanol-induced developmental defects can be ameliorated by increasing the levels of retinol, retinaldehyde, or retinaldehyde dehydrogenase. Acetaldehyde inhibits the production of retinoic acid by retinaldehyde dehydrogenase, further supporting the competition model. All of the evidence supports the reduction of retinoic acid signaling as the etiological trigger in the induction of FASD.

  4. Resin replica in enamel deproteinization and its effect on acid etching.

    Science.gov (United States)

    Espinosa, Roberto; Valencia, Roberto; Uribe, Mario; Ceja, Israel; Cruz, J; Saadia, Marc

    2010-01-01

    The goal of this in vitro study was to identify the topographical features of deproteinized (NaOCl) and etched with phosphoric acid (H3PO4) enamel surface, compared to phosphoric acid surface alone with a Resin Replica model. Ten extracted lower first and second permanent molars were polished with pumice and water, and then divided into 3 equal buccal sections having similar physical and chemical properties. The enamel surfaces of each group were subjected to the following treatments: Group A: Acid Etching with H3PO4 37% for 15 seconds. Group B: Sodium Hypochlorite (NaOCl) 5.25% for 60 seconds followed by Acid Etching with H3PO4 37% for 15 seconds. Group C; No treatment (control). All the samples were treated as follow: Adhesive and resin were applied to all groups after A, B and C treatment were performed; Then enamel/dentin decalcification and deproteinization and topographic SEM Resin Replica assessment were used to identify resin tags enamel surface quality penetration. Showed that group B reached an area of 7.52 mm of the total surface, with a 5.68 mm2 (73%) resin tag penetration equivalent type I and II etching pattern, 1.71 mm2 (26%) equivalent to type III etching pattern and 0.07 mm2 (1%) unaffected surface. Followed by group A with 7.48 mm2 of the total surface, with a 3.47 mm2 (46 %)resin tag penetration equivalent to type I and II etching pattern, 3.30 mm2 (45%)equivalent to type III etching pattern and 0.71 mm2, and (9%) unaffected surface. Group C did not show any resin tag penetration. A significant statistical diference (P enamel is deproteinizated with 5.25% NaOCl for 1 minute prior H3PO4, the surface and topographical features of the replica resin penetration surface increases significantly with type I-II etching pattern.

  5. Concentration and separation of trace metals with an arsonic acid resin.

    Science.gov (United States)

    Fritz, J S; Moyers, E M

    1976-08-01

    Macroporeus arsonic acid resins with different pore sizes and surface areas were prepared and the properties compared. One of the resins was used for concentration of trace metal ions from dimineralized water, tap-water, and sea-water. The effect of pH and complexing agents on the recovery of metal ions was studied. A method for separation of uranium(VI) and thorium(IV) from each other and from other metal ions was developed.

  6. The effect of Aspergillus niger mutagenization on citric acid biosynthesis

    Directory of Open Access Journals (Sweden)

    Stanisław Walisch

    2014-08-01

    Full Text Available The industrial A. niger strain producing citric acid was mutagenized with the use of new chemical mutagens: free nitroxyl radicals. Strains of higher citric acid production yield were obtained. Citric acid was produced in a shorter time compared to the initial strain. During 6-12 months of storage most of the strains preserved their positive features which proves that mutants with profitable biotechnological properties were obtained. These mutants are used in industrial process.

  7. Biosynthesis of 2-hydroxyisobutyric acid (2-HIBA) from renewable carbon

    OpenAIRE

    Müller Roland H; Rohwerder Thore

    2010-01-01

    Abstract Nowadays a growing demand for green chemicals and cleantech solutions is motivating the industry to strive for biobased building blocks. We have identified the tertiary carbon atom-containing 2-hydroxyisobutyric acid (2-HIBA) as an interesting building block for polymer synthesis. Starting from this carboxylic acid, practically all compounds possessing the isobutane structure are accessible by simple chemical conversions, e. g. the commodity methacrylic acid as well as isobutylene gl...

  8. Biosynthesis of vanillin via ferulic acid in Vanilla planifolia.

    Science.gov (United States)

    Negishi, Osamu; Sugiura, Kenji; Negishi, Yukiko

    2009-11-11

    (14)C-Labeled phenylalanine, 4-coumaric acid, 4-hydroxybenzaldehyde, 4-hydroxybenzyl alcohol, ferulic acid, and methionine were applied to disks of green vanilla pods 3 and 6 months after pollination (immature and mature pods), and the conversion of these compounds to vanillin or glucovanillin was investigated. In mature green vanilla pods, radioactivities of 11, 15, 29, and 24% from (14)C-labeled phenylalanine, 4-coumaric acid, ferulic acid, and methionine, respectively, were incorporated into glucovanillin within 24 h. In the incorporation processes of methionine and phenylalanine into glucovanillin, some of the (14)C labels were also trapped by the unlabeled ferulic acid. However, (14)C-labeled 4-hydroxybenzaldehyde and 4-hydroxybenzyl alcohol were not converted to glucovanillin. On the other hand, in immature green vanilla pods radioactivities of the above six compounds were not incorporated into glucovanillin. Although 4-coumaric acid, ferulic acid, 4-hydroxybenzaldehyde, and 4-hydroxybenzyl alcohol were converted to the respective glucose esters or glucosides and vanillin was converted to glucovanillin, their conversions were believed to be from the detoxication of the aglycones. These results suggest that the biosynthetic pathway for vanillin is 4-coumaric acid --> --> ferulic acid --> --> vanillin --> glucovanillin in mature vanilla pods.

  9. Biosynthesis of nervonic acid and perspectives for its production by microalgae and other microorganisms.

    Science.gov (United States)

    Fan, Yong; Meng, Hui-Min; Hu, Guang-Rong; Li, Fu-Li

    2018-04-01

    Nervonic acid (NA) is a major very long-chain monounsaturated fatty acid found in the white matter of mammalian brains, which plays a critical role in the treatment of psychotic disorders and neurological development. In the nature, NA has been synthesized by a handful plants, fungi, and microalgae. Although the metabolism of fatty acid has been studied for decades, the biosynthesis of NA has yet to be illustrated. Generally, the biosynthesis of NA is considered starting from oleic acid through fatty acid elongation, in which malonyl-CoA and long-chain acyl-CoA are firstly condensed by a rate-limiting enzyme 3-ketoacyl-CoA synthase (KCS). Heterologous expression of kcs gene from high NA producing species in plants and yeast has led to synthesis of NA. Nevertheless, it has also been reported that desaturases in a few plants can catalyze very long-chain saturated fatty acid into NA. This review highlights recent advances in the biosynthesis, the sources, and the biotechnological aspects of NA.

  10. Silver nanoparticle biosynthesis by using phenolic acids in rice husk extract as reducing agents and dispersants

    Directory of Open Access Journals (Sweden)

    Yee-Shing Liu

    2018-04-01

    Full Text Available Rice husk extract, obtained using acid and alkali pretreatment extraction (AAPE, contains bioactive compounds and exhibits reducing abilities. Phenolic composition in rice husk extract was analyzed and the mechanism of silver nanoparticle (AgNP biosynthesis by using AAPE rice husk extract was investigated in this study. Stable and spherically shaped AgNPs with a size of <15 nm were prepared under the following conditions: 0.001 M AgNO3, AAPE rice husk extract diluted 10 times, pH 10, and reacted at 25 °C for 60 min. Synergistic effects among phenolic acids contributed to the formation of AgNPs, with the acids acting as excellent reducing agents (owing to their abundant hydroxyl groups and excellent dispersants (owing to their derived CO groups, which enhanced the NPs' stability. Caffeic acid (CA was demonstrated to synthesize AgNPs independently and is suggested to be the most crucial compound for reducing Ag+ during the biosynthesis with rice husk extract. A possible mechanism and reaction process for the formation of AgNPs synthesized using CA in rice husk extracts is proposed. Keywords: Rice husk, Silver nanoparticles, Biosynthesis, Phenolic acid, Caffeic acid

  11. Effect of the chemical structure of anion exchange resin on the adsorption of humic acid: behavior and mechanism.

    Science.gov (United States)

    Shuang, Chendong; Wang, Jun; Li, Haibo; Li, Aimin; Zhou, Qing

    2015-01-01

    Polystyrenic (PS) anion-exchange resin and polyacrylic (PA) anion-exchange resin were used to investigate the effect of resin chemical structure on the adsorption of humic acid (HA). Due to the rearrangement of HA to form layers that function as barricades to further HA diffusion, PS resin exhibited 12.4 times slower kinetics for the initial adsorption rate and 8.4 times for the diffusion constant in comparison to that of the PA resin. An HA layer and a spherical cluster of HA can be observed on the surface of the PS and PA resins after adsorption, respectively. The considerable difference in HA adsorption between the PS and PA resins was due to the difference in molecule shape for interaction with different resin structures, which can essentially be explained by the hydrophobicity and various interactions of the PS resin. A given amount of HA occupies more positively charged sites and hydrophobic sites on the PS resin than were occupied by the same amount of HA on the PA resin. Increased pH resulted in an increase of HA adsorption onto the PA resin but a decrease in adsorption onto PS resin, as the non-electrostatic adsorption led to electrostatic repulsion between the HA attached to the resin and the HA dissolved in solution. These results suggest higher rates of adsorption and higher regeneration efficiency for interaction of HA with more hydrophilic anion exchange materials. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Effect of levulinic acid on pigment biosynthesis in Agmenellum quadruplicatum.

    Science.gov (United States)

    Kipe-Nolt, J A; Stevens, S E

    1979-01-01

    When levulinic acid was added to a growing culture of the cyanobacterium (blue-green alga) Agmenellum quadruplicatum PR-6, delta-aminoelevulinic acid accumulated in the medium and chlorophyll a synthesis and cell growth were inhibited, but there was a small amount of c-phycocyanin synthesis. The amount of delta-aminolevulinic acid produced in the treated culture did not fully account for the amount of pigment synthesized in the untreated control. Levulinic acid and either sodium nitrate or ammonium chloride were added to nitrogen-starved cultures of PR-6, and delta-aminolevulinic acid production and chlorophyll a and c-phycocyanin content were monitored. When ammonium chloride was added as a nitrogen source after nitrogen starvation, the cells recovered more rapidly than when sodium nitrate was added as a nitrogen source. In cultures recovering from nitrogen starvation, synthesis of c-phycocyanin occurred before synthesis of chlorophyll a. PMID:104956

  13. In vitro adsorption of oxalic acid and glyoxylic acid onto activated charcoal, resins and hydrous zirconium oxide

    NARCIS (Netherlands)

    Scholtens, R.; Scholten, J.; de Koning, H. W.; Tijssen, J.; ten Hoopen, H. W.; Olthuis, F. M.; Feijen, J.

    1982-01-01

    Patients suffering from primary hyperoxaluria show elevated plasma concentrations of oxalic acid and glyoxylic acid. The in vitro adsorption of these compounds into activated charcoal, a series of neutral and ion exchange resins and onto hydrous zirconium oxide has been investigated. Hydrous

  14. Large scale purification of puerarin from Puerariae Lobatae Radix through resins adsorption and acid hydrolysis.

    Science.gov (United States)

    Guo, Hai-Dong; Zhang, Qing-Feng; Chen, Ji-Guang; Shangguang, Xin-Cheng; Guo, Yu-Xian

    2015-02-01

    Puerarin is the major isoflavone of Puerariae Lobatae Radix. A method for large scale purification of puerarin was developed through resins adsorption and acid hydrolysis. The adsorption properties of six macroporous resins (D101, S-8, H103, X-5, HPD600, AB-8) were compared through the adsorption kinetics and equilibrium adsorption isotherms. Results showed that H103 resin had the best adsorption rate and capacity. The mass transfer zone motion model was further used for analyzing the fixed bed adsorption of H103 resin. Its length of mass transfer zone with 2mg/ml of puerarin in water and 10% ethanol at flow rate of 10ml/min were 41.6 and 47.5cm, while the equilibrium adsorption capacity was 165.03 and 102.88mg/g, respectively. By using 75% ethanol, puerarin could be well desorbed from the resin with recovery of 97.4%. Subsequently, H103 resin was successfully used for puerarin purification from Puerariae Lobatae Radix. The content of total isoflavones and puerarin in the resin adsorption product were 69.25% and 41.78%, respectively, which were about three times increased compared to the crude extract. Then, the product was hydrolyzed by 2.5M HCl at 90°C for 1h. Puerarin with purity of 90% and a byproduct daidzein with purity of 78% were obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Synthesis of hemicellulose-acrylic acid graft copolymer super water absorbent resin by ultrasonic irradiation technology

    Directory of Open Access Journals (Sweden)

    Fangfang LIU

    2015-12-01

    Full Text Available The hemicellulose super water absorbent resin is prepared by using ultrasonic irradiation technology, with the waste liquid produced during the preparation of viscose fiber which contains a large amount of hemicellulose as raw material, acrylic acid as graft monomer, N,N’-methylene bis acrylamide (NMBA as cross linking agent, and (NH42S2O8-NaHSO3 as the redox initiation system. The synthesis conditions, structure and water absorption ability of resin are discussed. The results indicate that water absorbency of the resin is 311 g/g, the tap water absorbency is 102 g/g, the normal saline absorbency is 55 g/g, and the artificial urine absorbency is 31 g/g under the optimal synthesis conditions, so the resin has great water absorption rate and water retaining capacity. The FT-IR and SEM analysis shows that the resin with honeycomb network structure is prepared. The successfully synthesized of the resin means that the hemicellulose waste liquid can be highly effectively recycled, and it provides a kind of new raw material for the synthesis of super water absorbent resin.

  16. Adsorption performance of salicylic acid on a novel resin with distinctive double pore structure.

    Science.gov (United States)

    Xiao, Guqing; Wen, Ruiming; Liu, Aijiao; He, Guowen; Wu, Dan

    2017-05-05

    Two approaches were used to synthesize two resins with different pore structures. In one way, the CH 2 Cl groups in macroporous chloromethylated polystyrene resin were transformed to methylene bridges, and achieved a hypercrosslinked resin with plentiful micropores (denoted GQ-06). In the other way, 50% of the CH 2 Cl groups in chloromethylated polystyrene resin was used to produce micropores, while the residual 50% of the CH 2 Cl groups was reacted with 2-aminopyridine, and prepared another resin with double pore structure of hypercrosslinked resin and macroporous resin (denoted GQ-11). The adsorption of salicylic acid (SA) on GQ-11 was investigated using GQ-06 as the reference adsorbent. The effect of pH on the adsorption of SA on GQ-06 was consistent with the dissociation curve of SA. The maximum adsorption capacity of SA on GQ-11 was observed at the solution pH of 2.64. The greater adsorption rate of SA on GQ-11 than that of GQ-06 was attributed to its double pore structure. The multifunctional adsorption mechanism of anion exchange and hydrophobic interaction resulted in the larger equilibrium capacity of SA on GQ-11 than that of GQ-06. GQ-06 and GQ-11 could be regenerated by absolute alcohol and 80% of alcohol -0.5mol/L of sodium hydroxide aqueous solution, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Biosynthesis of NAD from nicotinic acid and nicotinamide by resting cells of Arthrobacter globiformis

    International Nuclear Information System (INIS)

    Kuwahara, Masaaki

    1978-01-01

    Isotopically labeled nicotinic acid and nicotinamide were incorporated into the metabolites of nicotinic acid-dependent pathway (Preiss-Handler pathway) of the NAD biosynthesis by resting cells of Arthrobacter globiformis. Azaserine and adenosine markedly stimulated the accumulation of NAD in the cells. Radioactive nicotinic acid and nicotinamide were also incorporated into an unknown compound when the cells were incubated in the presence of azaserine. Cell-free extract of the organism showed the NAD synthetase activity, which required ammonium ion and ATP for the amidation of deamido-NAD. Adenosine inhibited the enzyme activity. The organism possessed nicotinamidase, suggesting deamidation is the first step in the biosynthesis of NAD from nicotinamide. The activity was inhibited by NAD, NADP and NMN. (auth.)

  18. Mycolic Acid-Containing Bacteria Induce Natural-Product Biosynthesis in Streptomyces Species▿ †

    Science.gov (United States)

    Onaka, Hiroyasu; Mori, Yukiko; Igarashi, Yasuhiro; Furumai, Tamotsu

    2011-01-01

    Natural products produced by microorganisms are important starting compounds for drug discovery. Secondary metabolites, including antibiotics, have been isolated from different Streptomyces species. The production of these metabolites depends on the culture conditions. Therefore, the development of a new culture method can facilitate the discovery of new natural products. Here, we show that mycolic acid-containing bacteria can influence the biosynthesis of cryptic natural products in Streptomyces species. The production of red pigment by Streptomyces lividans TK23 was induced by coculture with Tsukamurella pulmonis TP-B0596, which is a mycolic acid-containing bacterium. Only living cells induced this pigment production, which was not mediated by any substances. T. pulmonis could induce natural-product synthesis in other Streptomyces strains too: it altered natural-product biosynthesis in 88.4% of the Streptomyces strains isolated from soil. The other mycolic acid-containing bacteria, Rhodococcus erythropolis and Corynebacterium glutamicum, altered biosynthesis in 87.5 and 90.2% of the Streptomyces strains, respectively. The coculture broth of T. pulmonis and Streptomyces endus S-522 contained a novel antibiotic, which we named alchivemycin A. We concluded that the mycolic acid localized in the outer cell layer of the inducer bacterium influences secondary metabolism in Streptomyces, and this activity is a result of the direct interaction between the mycolic acid-containing bacteria and Streptomyces. We used these results to develop a new coculture method, called the combined-culture method, which facilitates the screening of natural products. PMID:21097597

  19. Reconstruction of diaminopimelic acid biosynthesis allows characterisation of Mycobacterium tuberculosis N-succinyl-L,L-diaminopimelic acid desuccinylase

    OpenAIRE

    Usha, Veeraraghavan; Lloyd, Adrian J.; Roper, David I.; Dowson, Christopher G.; Kozlov, Guennadi; Gehring, Kalle; Chauhan, Smita; Imam, Hasan T.; Blindauer, Claudia A.; Besra, Gurdyal S.

    2016-01-01

    With the increased incidence of tuberculosis (TB) caused by Mycobacterium tuberculosis there is an urgent need for new and better anti-tubercular drugs. N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) is a key enzyme in the succinylase pathway for the biosynthesis of meso-diaminopimelic acid (meso-DAP) and L-lysine. DapE is a zinc containing metallohydrolase which hydrolyses N-succinyl L,L diaminopimelic acid (L,L-NSDAP) to L,L-diaminopimelic acid (L,L-DAP) and succinate. M. tuberculo...

  20. Exposure to acid anhydrides in three resin and one cushioned flooring manufacturing plants.

    Science.gov (United States)

    van Tongeren, M J; Barker, R D; Gardiner, K; Harris, J M; Venables, K M; Taylor, A J; Harrington, J M

    1995-10-01

    Acid anhydrides are reactive organic chemicals of low molecular weight which cause occupational asthma. No previous research on the relationship between exposure to these chemicals and respiratory sensitization and development of occupational asthma has been reported. A retrospective cohort study was carried out in four factories (three alkyd resin factories and one cushioned flooring factory) to investigate the nature of exposure-response relationships for sensitization to phthalic anhydride (PA), trimellitic anhydride (TMA) and maleic anhydride (MA). This paper describes the results of full-shift and task-specific exposure measurements. Exposure to PA was low in relation to the Occupational Exposure Standard (OES). The highest full-shift PA exposures occurred among resin operators in the resin factory that used solid PA as compared to other resin factories where liquid PA was used. Arithmetic mean exposure levels to TMA and MA in the resin factories were well below their respective OESs. Short-term high exposures occurred during loading of acid anhydrides into the reactors and sampling and testing of the resin. Relatively high full-shift exposure to TMA occurred in the cushioned flooring factory, although no high peak exposures were detected.

  1. Sorption of Pu(IV) from nitric acid by bifunctional anion-exchange resins

    International Nuclear Information System (INIS)

    Bartsch, R.A.; Zhang, Z.Y.; Elshani, S.; Zhao, W.; Jarvinen, G.D.; Barr, M.E.; Marsh, S.F.; Chamberlin, R.M.

    1999-01-01

    Anion exchange is attractive for separating plutonium because the Pu(IV) nitrate complex is very strongly sorbed and few other metal ions form competing anionic nitrate complexes. The major disadvantage of this process has been the unusually slow rate at which the Pu(IV) nitrate complex is sorbed by the resin. The paper summarizes the concept of bifunctional anion-exchange resins, proposed mechanism for Pu(IV) sorption, synthesis of the alkylating agent, calculation of K d values from Pu(IV) sorption results, and conclusions from the study of Pu(IV) sorption from 7M nitric acid by macroporous anion-exchange resins including level of crosslinking, level of alkylation, length of spacer, and bifunctional vs. monofunctional anion-exchange resins

  2. Improvement of Folate Biosynthesis by Lactic Acid Bacteria Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Norfarina Muhamad Nor

    2010-01-01

    Full Text Available Lactic acid bacteria (Lactococcus lactis NZ9000, Lactococcus lactis MG1363, Lactobacillus plantarum I-UL4 and Lactobacillus johnsonii DSM 20553 have been screened for their ability to produce folate intracellularly and/or extracellularly. L. plantarum I-UL4 was shown to be superior producer of folate compared to other strains. Statistically based experimental designs were used to optimize the medium formulation for the growth of L. plantarum I-UL4 and folate biosynthesis. The optimal values of important factors were determined by response surface methodology (RSM. The effects of carbon sources, nitrogen sources and para-aminobenzoic acid (PABA concentrations on folate biosynthesis were determined prior to RSM study. The biosynthesis of folate by L. plantarum I-UL4 increased from 36.36 to 60.39 µg/L using the optimized medium formulation compared to the selective Man de Rogosa Sharpe (MRS medium. Conditions for the optimal growth of L. plantarum I-UL4 and folate biosynthesis as suggested by RSM were as follows: lactose 20 g/L, meat extract 16.57 g/L and PABA 10 µM.

  3. Green biorefinery: separation of lactic acid from grass silage juice by chromatography using neutral polymeric resin.

    Science.gov (United States)

    Thang, Vu Hong; Novalin, Senad

    2008-07-01

    The aim of this work was to recover lactic acid in undissociated form from grass silage juice. For this aim, chromatographic separation using neutral polymeric resin Amberlite XAD1600 was investigated. Up to now, there is no hint in the literatures about using neutral polymeric resin for lactic acid separation from a mixture. Important factors (flow-rate, concentration of feed and loaded volume) that affect separation performance were firstly investigated with model solutions. The obtained results showed that lactic acid solutions with the purity varying from 93.2% to 99.9% could be obtained at the recovery yields over 99.4%. After that, trials with silage juice were carried out. Due to the complex composition of the feed, the purity of products decreased to 94% at a recovery yield of 97%. Although 99% of inorganic salts and sugars were separated from lactic acid organic acids in general and acetic acid in particular caused a purity problem. It seems that organic acids could not be separated from lactic acid by neutral resin Amberlite XAD1600. Besides the organic acid problem, some amino acids were remained in the products as impurities.

  4. Crypthophilic acids A, B, and C: resin glycosides from aerial parts of Scrophularia crypthophila.

    Science.gov (United States)

    Caliş, Ihsan; Sezgin, Yükselen; Dönmez, Ali A; Rüedi, Peter; Tasdemir, Deniz

    2007-01-01

    The water-soluble part of the methanolic extract from the aerial parts of Scrophularia crypthophila, through chromatographic methods, yielded three new resin glycosides, crypthophilic acids A - C (1-3). Compounds 1-3 are tetraglycosides of (+)-3S,12S-dihydroxypalmitic acid. The structures of these and 10 known compounds were elucidated by spectroscopic and chemical means. All natural resin glycosides known so far have been obtained from Convolvulaceae plants; this is the first report of such glycosides from another, taxonomically unrelated family (Scrophulariaceae).

  5. Modulation of cytochrome biosynthesis in yeast by antimetabolite action of levulinic acid.

    Science.gov (United States)

    Malamud, D R; Borralho, L M; Panek, A D; Mattoon, J R

    1979-01-01

    Levulinic acid, a competitive inhibitor of delta-aminolevulinic acid dehydratase, was used to inhibit cytochrome biosynthesis in growing yeast cells. In Saccharomyces cerevisiae the antimetabolite acts by inhibiting delta-aminolevulinic acid dehydratase in vivo, causing an accumulation of intracellular delta-aminolevulinic acid and simultaneous decreases in all classes of mitochondrial cytochromes. Changes in cellular cytochrome content with increasing levulinic acid concentration suggested the existence of different regulatory patterns in S. cerevisiae and Candida utilis. In C. utilis, cytochrome a.a3 formation is very resistant to the antimetabolite action of levulinic acid. In this aerobic yeast, cytochrome c+c1 is the most sensitive to levulinic acid, and cytochrome b exhibits intermediate sensitivity. PMID:378939

  6. Dimerisation of isobutene on acidic ion-exchange resins

    OpenAIRE

    Honkela, Maija

    2005-01-01

    Dimerisation of isobutene produces diisobutenes that can be hydrogenated to isooctane (2,2,4-trimethyl pentane). Isooctane can be used as a high octane gasoline component. The aim of this work was to study the selective production of diisobutenes through the dimerisation of isobutene on ion-exchange resin catalysts and to construct kinetic models for the reactions in the system for reactor design purposes. High selectivities for diisobutenes were obtained in the presence of polar componen...

  7. Branched chain amino acid metabolism in the biosynthesis of Lycopersicon pennellii glucose esters

    International Nuclear Information System (INIS)

    Walters, D.S.; Steffens, J.C.

    1990-01-01

    Lycopersicon pennellii Corr. (D'Arcy) an insect-resistant, wild tomato possesses high densities of glandular trichomes which exude a mixture of 2,3,4-tri-O-acylated glucose esters that function as a physical impediment and feeding deterrent to small arthropod pests. The acyl moieties are branched C 4 and C 5 acids, and branched and straight chain C 10 , C 11 , and C 12 acids. The structure of the branched acyl constituents suggests that the branched chain amino acid biosynthetic pathway participates in their biosynthesis. [ 14 C]Valine and deuterated branched chain amino acids (and their oxo-acid derivatives) were incorporated into branched C 4 and C 5 acid groups of glucose esters by a process of transamination, oxidative decarboxylation and subsequent acylation. C 4 and C 5 branched acids were elongated by two carbon units to produce the branched C 10 -C 12 groups. Norvaline, norleucine, allylglycine, and methionine also were processed into acyl moieties and secreted from the trichomes as glucose esters. Changes in the acyl composition of the glucose esters following sulfonylurea herbicide administration support the participation of acetohydroxyacid synthetase and the other enzymes of branched amino acid biosynthesis in the production of glucose esters

  8. The hormonal regulation of purine biosynthesis: control of the inosinic acid branch point

    International Nuclear Information System (INIS)

    Pizzichini, M.; Di Stefano, A.; Marinello, E.; Pompucci, G.

    1986-01-01

    This paper studies the behavior of purine biosynthesis de novo in the levator animal muscle (LAM) of adult rats, before, after castration, and after testosterone administration. The incorporation of C 14-formate into the acid-soluble bases was performed as an index of the overall rate of purine nucleotide synthesis. It is shown that castration reduces the content, the specific activity of total bases and of the single bases in the LAM, indicating an inferior turnover. The increased turnover of guanylic acid, which is always present although not as much as adenylic acid, will favor the sunthesis of RNA in the sexual organs

  9. Proteomic evaluation of free fatty acid biosynthesis in Jatropha ...

    African Journals Online (AJOL)

    WincoolV5

    2013-05-22

    May 22, 2013 ... was analyzed at each stage using gas chromatography after conversion to methyl esters. Fatty acid levels were found to .... mortar and pestle and then suspended in 500 µL of hexane / 500 mg ground nut kernel with ... (GC) with a GC-2010A (Shimadzu, Japan) fitted with a capillary column (OmegawaxTM ...

  10. Overexpression of a Gene Involved in Phytic Acid Biosynthesis Substantially Increases Phytic Acid and Total Phosphorus in Rice Seeds

    Directory of Open Access Journals (Sweden)

    Yusuke Tagashira

    2015-04-01

    Full Text Available The manipulation of seed phosphorus is important for seedling growth and environmental P sustainability in agriculture. The mechanism of regulating P content in seed, however, is poorly understood. To study regulation of total P, we focused on phytic acid (inositol hexakisphosphate; InsP6 biosynthesis-related genes, as InsP6 is a major storage form of P in seeds. The rice (Oryza sativa L. low phytic acid mutant lpa1-1 has been identified as a homolog of archael 2-phosphoglycerate kinase. The homolog might act as an inositol monophosphate kinase, which catalyzes a key step in InsP6 biosynthesis. Overexpression of the homolog in transgenic rice resulted in a significant increase in total P content in seed, due to increases in InsP6 and inorganic phosphates. On the other hand, overexpression of genes that catalyze the first and last steps of InsP6 biosynthesis could not increase total P levels. From the experiments using developing seeds, it is suggested that the activation of InsP6 biosynthesis in both very early and very late periods of seed development increases the influx of P from vegetative organs into seeds. This is the first report from a study attempting to elevate the P levels of seed through a transgenic approach.

  11. Chemically modified polymeric resins for separation of cations, organic acids, and small polar moleculea by high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Morris, John B. [Iowa State Univ., Ames, IA (United States)

    1993-07-01

    This thesis is divided into 4 parts: a review, ion chromatography of metal cations on carboxylic resins, separation of hydrophilic organic acids and small polar compounds on macroporous resin columns, and use of eluent modifiers for liquid chromatographic separation of carboxylic acids using conductivity detection.

  12. Influence of caffeine and hyaluronic acid on collagen biosynthesis in human skin fibroblasts

    Directory of Open Access Journals (Sweden)

    Donejko M

    2014-10-01

    Full Text Available Magdalena Donejko,1 Andrzej Przylipiak,1 Edyta Rysiak,2 Katarzyna Głuszuk,2 Arkadiusz Surażyński2 1Department of Esthetic Medicine, 2Department of Medicinal Chemistry, Faculty of Pharmacy, Medical University of Białystok, Białystok, Poland Aim: The aim of this study was to evaluate the effect of caffeine on collagen biosynthesis in human skin fibroblasts and the influence of hyaluronic acid (HA on this process. Materials and methods: Collagen, [3H]-thymidine incorporation, and prolidase activity were measured in confluent human skin fibroblast cultures that had been treated with 1, 2, and 5 mM caffeine and with caffeine and 500 µg/mL HA. Western immunoblot analysis was performed to evaluate expression of ß1-integrin receptor, insulin-like growth factor receptor phospho-Akt protein and mitogen-activated protein kinase (phospho-extracellular signal-regulated kinase. Results: Caffeine inhibited collagen biosynthesis in a dose-dependent manner. The mechanism of this process was found at the level of prolidase activity. Caffeine significantly inhibited the enzyme activity. The addition of HA had no effect on collagen biosynthesis or prolidase activity in fibroblasts incubated with caffeine. Caffeine also had an inhibitory effect on DNA biosynthesis. HA, however, did not have any significant effect on this process. The inhibition of the expression of ß1-integrin and insulin-like growth factor receptor in fibroblasts incubated with the caffeine indicates a possible mechanism of inhibition of collagen biosynthesis. Conclusion: Caffeine reduces collagen synthesis in human cultured skin fibroblasts. HA did not have any significant protective effect on this process. This is the first study to our knowledge that reports caffeine-induced inhibition of collagen synthesis in human skin fibroblasts. Keywords: collagen, caffeine, hyaluronic acid, fibroblast

  13. Exposure to wood dust, resin acids, and volatile organic compounds during production of wood pellets.

    Science.gov (United States)

    Hagström, Katja; Axelsson, Sara; Arvidsson, Helena; Bryngelsson, Ing-Liss; Lundholm, Cecilia; Eriksson, Kåre

    2008-05-01

    The main aim of this study was to investigate exposure to airborne substances that are potentially harmful to health during the production of wood pellets, including wood dust, monoterpenes, and resin acids, and as an indicator of diesel exhaust nitrogen dioxide. In addition, area measurements were taken to assess background exposure levels of these substances, volatile organic compounds (VOCs), and carbon monoxide. Measurements were taken at four wood pellet production plants from May 2004 to April 2005. Forty-four workers participated in the study, and a total of 68 personal measurements were taken to determine personal exposure to wood dust (inhalable and total dust), resin acids, monoterpenes, and nitrogen dioxide. In addition, 42 measurements of nitrogen dioxide and 71 measurements of total dust, resin acids, monoterpenes, VOCs, and carbon monoxide were taken to quantify their indoor area concentrations. Personal exposure levels to wood dust were high, and a third of the measured levels of inhalable dust exceeded the Swedish occupational exposure limit (OEL) of 2 mg/m3. Parallel measurements of inhalable and total dust indicated that the former were, on average, 3.2 times higher than the latter. The data indicate that workers at the plants are exposed to significant amounts of the resin acid 7-oxodehydroabietic acid in the air, an observation that has not been recorded previously at wood processing and handling plants. The study also found evidence of exposure to dehydroabietic acid, and exposure levels for resin acids approached 74% of the British OEL for colophony, set at 50 microg/m3. Personal exposure levels to monoterpenes and nitrogen dioxide were low. Area sampling measurements indicated that aldehydes and terpenes were the most abundant VOCs, suggesting that measuring personal exposure to aldehydes might be of interest. Carbon monoxide levels were under the detection limit in all area measurements. High wood dust exposure levels are likely to have

  14. Effect of sulfuric acid etching of polyetheretherketone on the shear bond strength to resin cements.

    Science.gov (United States)

    Sproesser, Oliver; Schmidlin, Patrick R; Uhrenbacher, Julia; Roos, Malgorzata; Gernet, Wolfgang; Stawarczyk, Bogna

    2014-10-01

    To examine the influence of etching duration on the bond strength of PEEK substrate in combination with different resin composite cements. In total, 448 PEEK specimens were fabricated, etched with sulfuric acid for 5, 15, 30, 60, 90, 120, and 300 s and then luted with two conventional resin cements (RelyX ARC and Variolink II) and one self-adhesive resin cement (Clearfil SA Cement) (n = 18/subgroup). Non-etched specimens served as the control group. Specimens were stored in distilled water for 28 days at 37°C and shear bond strengths were measured. Data were analyzed nonparametrically using Kruskal-Wallis-H (p sulfuric acid seems to be suitable and effective for PEEK surface pre-treatment, further investigations are required to examine the effect of other adhesive systems and cements.

  15. Metabolic engineering of Rhizopus oryzae: Effects of overexpressing pyc and pepc genes on fumaric acid biosynthesis from glucose

    Science.gov (United States)

    Fumaric acid, a dicarboxylic acid used as a food acidulant and in manufacturing synthetic resins, can be produced from glucose in fermentation by Rhizopus oryzae. However, the fumaric acid yield is limited by the co-production of ethanol and other byproducts. To increase fumaric acid production, ove...

  16. Engineering plastid fatty acid biosynthesis to improve food quality and biofuel production in higher plants.

    Science.gov (United States)

    Rogalski, Marcelo; Carrer, Helaine

    2011-06-01

    The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  17. Traumatic Acid Reduces Oxidative Stress and Enhances Collagen Biosynthesis in Cultured Human Skin Fibroblasts.

    Science.gov (United States)

    Jabłońska-Trypuć, Agata; Pankiewicz, Walentyn; Czerpak, Romuald

    2016-09-01

    Traumatic acid (TA) is a plant hormone (cytokinin) that in terms of chemical structure belongs to the group of fatty acids derivatives. It was isolated from Phaseolus vulgaris. TA activity and its influence on human cells and organism has not previously been the subject of research. The aim of this study was to examine the effects of TA on collagen content and basic oxidative stress parameters, such as antioxidative enzyme activity, reduced glutathione, thiol group content, and lipid peroxidation in physiological conditions. The results show a stimulatory effect of TA on tested parameters. TA caused a decrease in membrane phospholipid peroxidation and exhibited protective properties against ROS production. It also increases protein and collagen biosynthesis and its secretion into the culture medium. The present findings reveal that TA exhibits multiple and complex activity in fibroblast cells in vitro. TA, with its activity similar to unsaturated fatty acids, shows antioxidant and stimulatory effects on collagen biosynthesis. It is a potentially powerful agent with applications in the treatment of many skin diseases connected with oxidative stress and collagen biosynthesis disorders.

  18. Esterification of oleic acid with ethanol catalyzed by sulfonated cation exchange resin: Experimental and kinetic studies

    International Nuclear Information System (INIS)

    Jiang, Yuwang; Lu, Jie; Sun, Kaian; Ma, Lingling; Ding, Jincheng

    2013-01-01

    Graphical abstract: - Highlights: • Esterification of oleic acid with ethanol was investigated in the presence of sulfonated cation exchange resin. • We studied kinetic model of the esterification of oleic acid with ethanol according to experimental data. • The proposed kinetic model can well predict oleic acid conversion. - Abstract: This paper investigated the effects of ethanol to oleic acid molar ratio, reaction temperature, catalyst loading, water content and catalyst recycling on sulfonated cation exchange resin in a stirred batch reactor under atmospheric pressure. When the esterification was carried out with an ethanol to oleic acid (42.4 g) molar ratio of 9:1, reflux of ethanol at 82 °C, 20 g of catalyst and 8 h of reaction time, the oleic acid conversion rate reached approximately 93%. A pseudo-homogeneous kinetic model for describing the esterification of oleic acid with ethanol by the sulfonated cation exchange resin was developed on the basis of laboratorial results. The kinetic model can well predict the oleic acid conversion

  19. Tape-stripping as a method for measuring dermal exposure to resin acids during wood pellet production.

    Science.gov (United States)

    Eriksson, Kåre; Hagström, Katja; Axelsson, Sara; Nylander-French, Leena

    2008-03-01

    The purpose of this study was to develop a sensitive and specific method for quantifying dermal exposure to the resin acids 7-oxodehydroabietic acid (7-OXO), dehydroabietic acid (DHAA), abietic acid (AA), and pimaric acid (PA). In addition the method was evaluated in occupational settings during production of wood pellets. Tape-strips were spiked with the substances to evaluate the recovery of the acids from the tape. The removal efficiency of the tape was assessed by tape-stripping a specified area on a glass plate spiked with resin acids. The recovery of the acids from human skin in vivo was evaluated by applying acids in methanol onto the skin of volunteers. Occupational dermal exposure to the resin acids was assessed by tape-stripping the skin of workers involved in the production of wood pellets. The resin acids were analyzed by liquid chromatography mass spectrometry (LC-MS). The limit of detection was 15 pg (7-OXO), 150 pg (DHAA), 285 pg (AA) and 471 pg (PA) per injection. The recovery from spiked tapes was in general 100%. The removal efficiency of the tape was 48-101%. Recovery tests from human skin in vivo showed a mean recovery of 27%. Quantifiable amounts of resin acids were observed on four different skin areas with an increase in exposure during a work shift. This study shows that occupational dermal exposure to resin acids can be assessed by tape-stripping and quantified by LC-MS.

  20. A convenient procedure for the solid-phase synthesis of hydroxamic acids on PEGA resins

    DEFF Research Database (Denmark)

    Nandurkar, Nitin Subhash; Petersen, Rico; Qvortrup, Katrine

    2011-01-01

    An efficient method for the solid-phase synthesis of hydroxamic acids is described. The method comprises the nucleophilic displacement of esters immobilized on PEGA resins with hydroxylamine/sodium hydroxide in isopropanol. The hydroxyaminolysis protocol is compatible with a broad range of PEGA...

  1. Influence of the Functionalization Degree of Acidic Ion-Exchange Resins on Ethyl Octyl Ether Formation

    Czech Academy of Sciences Publication Activity Database

    Guilera, J.; Hanková, Libuše; Jeřábek, Karel; Ramírez, E.; Tejero, J.

    2014-01-01

    Roč. 78, MAY (2014), s. 14-22 ISSN 1381-5148 Grant - others:SEURDO(ES) CTQ2010-16047 Institutional support: RVO:67985858 Keywords : acidic ion-exchange resin * sulfonation degree * ISEC Subject RIV: CC - Organic Chemistry Impact factor: 2.515, year: 2014

  2. Effects of different sulfuric acid etching concentrations on PEEK surface bonding to resin composite.

    Science.gov (United States)

    Chaijareenont, Pisaisit; Prakhamsai, Sasiprapha; Silthampitag, Patcharawan; Takahashi, Hidekazu; Arksornnukit, Mansuang

    2018-01-26

    This study evaluated the effects of surface pretreatment with different concentrations of sulfuric acid etching on surface properties and bonding between Polyetheretherketone (PEEK) and a resin composite. Six groups of surface pretreatment (no pretreatment, etched with 70, 80, 85, 90, and 98% sulfuric acid for 60 s) were treated on PEEK. Surface roughness, scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses were examined. Shear bond strength (SBS) and cross-sectional observations of the interfaces were performed. One-way ANOVA analysis revealed differences in surface roughness and SBS between groups. The 90 and 98% sulfuric acid etching significantly achieved the highest SBS (psulfuric acid etching were suggested to be the optimal concentration to improve adhesion between PEEK and the resin composite.

  3. Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

    Science.gov (United States)

    Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

    2011-01-01

    A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

  4. Arabidopsis acetyl-amido synthetase GH3.5 involvement in camalexin biosynthesis through conjugation of indole-3-carboxylic acid and cysteine and upregulation of camalexin biosynthesis genes.

    Science.gov (United States)

    Wang, Mu-Yang; Liu, Xue-Ting; Chen, Ying; Xu, Xiao-Jing; Yu, Biao; Zhang, Shu-Qun; Li, Qun; He, Zu-Hua

    2012-07-01

    Camalexin (3-thiazol-2'-yl-indole) is the major phytoalexin found in Arabidopsis thaliana. Several key intermediates and corresponding enzymes have been identified in camalexin biosynthesis through mutant screening and biochemical experiments. Camalexin is formed when indole-3-acetonitrile (IAN) is catalyzed by the cytochrome P450 monooxygenase CYP71A13. Here, we demonstrate that the Arabidopsis GH3.5 protein, a multifunctional acetyl-amido synthetase, is involved in camalexin biosynthesis via conjugating indole-3-carboxylic acid (ICA) and cysteine (Cys) and regulating camalexin biosynthesis genes. Camalexin levels were increased in the activation-tagged mutant gh3.5-1D in both Col-0 and cyp71A13-2 mutant backgrounds after pathogen infection. The recombinant GH3.5 protein catalyzed the conjugation of ICA and Cys to form a possible intermediate indole-3-acyl-cysteinate (ICA(Cys)) in vitro. In support of the in vitro reaction, feeding with ICA and Cys increased camalexin levels in Col-0 and gh3.5-1D. Dihydrocamalexic acid (DHCA), the precursor of camalexin and the substrate for PAD3, was accumulated in gh3.5-1D/pad3-1, suggesting that ICA(Cys) could be an additional precursor of DHCA for camalexin biosynthesis. Furthermore, expression of the major camalexin biosynthesis genes CYP79B2, CYP71A12, CYP71A13 and PAD3 was strongly induced in gh3.5-1D. Our study suggests that GH3.5 is involved in camalexin biosynthesis through direct catalyzation of the formation of ICA(Cys), and upregulation of the major biosynthetic pathway genes. © 2012 Institute of Botany, Chinese Academy of Sciences.

  5. Abscisic acid biosynthesis in water-stressed leaves

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi.

    1989-01-01

    Although abscisic acid (ABA) was discovered 30 years ago, very little is known about its biosynthetic pathway in higher plants. Two hypotheses have been proposed: (i) a direct pathway involving only C-15 intermediates like farnesyl pyrophosphate, (ii) an indirect pathway involving C-40 intermediates like the xanthophylls. When {sup 14}CO{sub 2} was fed into greened bean plants, the {sup 14}C specific activity of ABA was always lower than those in xanthophylls, such as violaxanthin and lutein, regardless of {sup 12}CO{sub 2} chase periods. The ABA accumulation in green leaves was not affected by fluridone when plants were stressed once, but the {sup 14}C incorporation into ABA was inhibited to the same extent as those of xanthophylls. The incorporation of {sup 18}O into the ABA ring when violaxanthin was labeled by {sup 18}O in vivo via the violaxanthin cycle indicates that at least a portion of ABA was derived from {sup 18}O-labeled violaxanthin during water stress.

  6. Isolation of 14{sub C} labelled amino acids by biosynthesis in maize plants (Zea mais L.); Obtencin de aminoacidos marcados con 14{sub C} por biosintesis en plantulas de maiz (Zea mais L)

    Energy Technology Data Exchange (ETDEWEB)

    Carreras, N.; Mazon, M. P.

    1983-07-01

    A method of obtaining 14{sub C} labelled amino acids by biosynthesis in maize plants which had assimilated 14CO{sub 2}, has been assayed. The plants were labelled for 60 minutes with 14{sub C}O2 produced from Ba 14{sub C}O3 (specific activity of 148 KBq/{mu}mol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic column (Dowex 50-X4). (Author) 56 refs.

  7. Adsorption of uranium ions by crosslinked polyester resin functionalized with acrylic acid from aqueous solutions

    International Nuclear Information System (INIS)

    Cemal Oezeroglu; Niluefer Metin

    2012-01-01

    In this paper, the crosslinked polyester resin containing acrylic acid functional groups was used for the adsorption of uranium ions from aqueous solutions. For this purpose, the crosslinked polyester resin of unsaturated polyester in styrene monomer (Polipol 353, Poliya) and acrylic acid as weight percentage at 80 and 20%, respectively was synthesized by using methyl ethyl ketone peroxide (MEKp, Butanox M60, Azo Nobel)-cobalt octoate initiator system. The adsorption of uranium ions on the sample (0.05 g copolymer and 5 mL of U(VI) solution were mixed) of the crosslinked polyester resin functionalized with acrylic acid was carried out in a batch reactor. The effects of adsorption parameters of the contact time, temperature, pH of solution and initial uranium(VI) concentration for U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid were investigated. The adsorption data obtained from experimental results depending on the initial U(VI) concentration were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The adsorption capacity and free energy change were determined by using D-R isotherm. The obtained experimental adsorption data depending on temperature were evaluated to calculate the thermodynamic parameters of enthalpy (ΔH o ), entropy (ΔS o ) and free energy change (ΔG o ) for the U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid from aqueous solutions. The obtained adsorption data depending on contact time were analyzed by using adsorption models such as the modified Freundlich, Elovich, pseudo-first order and pseudo-second-order kinetic models. (author)

  8. Artificial biosynthesis of phenylpropanoic acids in a tyrosine overproducing Escherichia coli strain

    Directory of Open Access Journals (Sweden)

    Kang Sun-Young

    2012-12-01

    Full Text Available Abstract Background The phenylpropanoid metabolites are an extremely diverse group of natural products biosynthesized by plants, fungi, and bacteria. Although these compounds are widely used in human health care and nutrition services, their availability is limited by regional variations, and isolation of single compounds from plants is often difficult. Recent advances in synthetic biology and metabolic engineering have enabled artificial production of plant secondary metabolites in microorganisms. Results We develop an Escherichia coli system containing an artificial biosynthetic pathway that yields phenylpropanoic acids, such as 4-coumaric acid, caffeic acid, and ferulic acid, from simple carbon sources. These artificial biosynthetic pathways contained a codon-optimized tal gene that improved the productivity of 4-coumaric acid and ferulic acid, but not caffeic acid in a minimal salt medium. These heterologous pathways extended in E. coli that had biosynthesis machinery overproducing tyrosine. Finally, the titers of 4-coumaric acid, caffeic acid, and ferulic acid reached 974 mg/L, 150 mg/L, and 196 mg/L, respectively, in shake flasks after 36-hour cultivation. Conclusions We achieved one gram per liter scale production of 4-coumaric acid. In addition, maximum titers of 150 mg/L of caffeic acid and 196 mg/L of ferulic acid were achieved. Phenylpropanoic acids, such as 4-coumaric acid, caffeic acid, and ferulic acid, have a great potential for pharmaceutical applications and food ingredients. This work forms a basis for further improvement in production and opens the possibility of microbial synthesis of more complex plant secondary metabolites derived from phenylpropanoic acids.

  9. Eco-friendly Crosslinking Agent for Acid Functional Acrylic Resin

    Directory of Open Access Journals (Sweden)

    Archana Shah

    2009-01-01

    Full Text Available Oil from J. multifida was extracted and it was first converted into N,N-bis(2-hydroxyethyl Jatropha fatty amide (HEJFA. HEJFA has been synthesized by reaction between Jatropha oil and diethanol amine in presence of zinc oxide as a catalyst. The reaction is relatively rapid and proceeded to high yield at 200±5 OC. The resulting HEJFA was used to formulate thermosetting coating compositions. Films were cured at ambient (air drying and elevated (stove drying temperatures using N, N-bis(2-hydroxyethyl Jatropha fatty amide (HEJFA as eco-friendly crosslinking agent for acrylic resin. The coating performance of the various compositions was tested by measurement of scratch hardness, impact strength and chemical resistance. The results show better performance of the HEJFA based compositions compared to butylated melamine formaldehyde (MF based compositions.

  10. Mechanism of biosynthesis of unsaturated fatty acids in Pseudomonas sp. strain E-3, a psychrotrophic bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Wada, M.; Fukunaga, N.; Sasaki, S. (Hokkaido Univ., Sapporo (Japan))

    1989-08-01

    Biosynthesis of palmitic, palmitoleic, and cis-vaccenic acids in Pseudomonas sp. strain E-3 was investigated with in vitro and in vivo systems. (1-{sup 14}C)palmitic acid was aerobically converted to palmitoleate and cis-vaccenate, and the radioactivities on their carboxyl carbons were 100 and 43%, respectively, of the total radioactivity in the fatty acids. Palmitoyl coenzyme A desaturase activity was found in the membrane fraction. (1-{sup 14}C)stearic acid was converted to octadecenoate and C16 fatty acids. The octadecenoate contained oleate and cis-vaccenate, but only oleate was produced in the presence of cerulenin. (1-{sup 14}C)lauric acid was aerobically converted to palmitate, palmitoleate, and cis-vaccenate. Under anaerobic conditions, palmitate (62%), palmitoleate (4%), and cis-vaccenate (34%) were produced from (1-{sup 14}C)acetic acid, while they amounted to 48, 39, and 14%, respectively, under aerobic conditions. In these incorporation experiments, 3 to 19% of the added radioactivity was detected in released {sup 14}CO{sub 2}, indicating that part of the added fatty acids were oxidatively decomposed. Partially purified fatty acid synthetase produced saturated and unsaturated fatty acids with chain lengths of C10 to C18. These results indicated that both aerobic and anaerobic mechanisms for the synthesis of unsaturated fatty acid are operating in this bacterium.

  11. Biophysical study of resin acid effects on phospholipid membrane structure and properties

    DEFF Research Database (Denmark)

    Jagalski, Vivien; Barker, Robert; Topgaard, Daniel

    2016-01-01

    Hydrophobic resin acids (RAs) are synthesized by conifer trees as part of their defense mechanisms. One of the functions of RAs in plant defense is suggested to be the perturbation of the cellular membrane. However, there is a vast diversity of chemical structures within this class of molecules......, and there are no clear correlations to the molecular mechanisms behind the RA's toxicity. In this study we unravel the molecular interactions of the three closely related RAs dehydroabietic acid, neoabietic acid, and the synthetic analogue dichlorodehydroabietic acid with dipalmitoylphosphatidylcholine (DPPC) model...... are correlated with the physical chemical properties of the RA and their toxicity....

  12. Sorption Efficiency of a New Sorbent towards Cadmium(II: Methylphosphonic Acid Grafted Polystyrene Resin

    Directory of Open Access Journals (Sweden)

    Nacer Ferrah

    2013-01-01

    Full Text Available A new chelating polymeric sorbent has been developed using polystyrene resin grafted with phosphonic acid. After characterization by FTIR and elementary analysis, the new resin has been investigated in liquid-solid extraction of cadmium(II. The results indicated that phosphonic resin could adsorb Cd(II ion effectively from aqueous solution. The adsorption was strongly dependent on the pH of the medium and the optimum pH value level for better sorption was between 3.2 and 5.2. The influence of other analytical parameters including contact time, amount of resin, metal ion concentration, and the presence of some electrolytes was investigated. The maximum uptake capacity of Cd(II ions was 37,9 mg·g−1 grafted resin at ambient temperature, at an initial pH value of 5.0. The overall adsorption process was best described by pseudo second-order kinetic. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. Furthermore, more than 92% of Cd(II could be eluted by using 1.0 mol·L−1 HCl in one cycle.

  13. Simultaneous separation and detection of actinides in acidic solutions using an extractive scintillating resin.

    Science.gov (United States)

    Roane, J E; DeVol, T A

    2002-11-01

    An extractive scintillating resin was evaluated for the simultaneous separation and detection of actinides in acidic solutions. The transuranic extractive scintillating (TRU-ES) resin is composed of an inert macroporous polystyrene core impregnated with organic fluors (diphenyloxazole and 1,4-bis-(4-methyl-5-phenyl-2-oxazolyl)benzene) and an extractant (octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide in tributyl phosphate). The TRU-ES resin was packed into FEP Teflon tubing to produce a flow cell (0.2-mL free column volume), which is placed into a scintillation detection system to obtain pulse height spectra and time series data during loading and elution of actinides onto/from the resin. The alpha-particle absolute detection efficiencies ranged from 77% to 96.5%, depending on the alpha energy and quench. In addition to the on-line analyses, off-line analyses of the effluent can be conducted using conventional detection methods. The TRU-ES resin was applied to the quantification of a mixed radionuclide solution and two actual waste samples. The on-line characterization of the mixed radionuclide solution was within 10% of the reported activities whereas the agreement with the waste samples was not as good due to sorption onto the sample container walls and the oxidation state of plutonium. Agreement between the on-line and off-line analyses was within 35% of one another for both waste samples.

  14. Inhibition of platelet aggregation by diterpene acids from Pinus massoniana resin.

    Science.gov (United States)

    Cheung, H T; Fu, S L; Smal, M A

    1994-01-01

    The acidic fraction of the resin of Pinus massoniana Lamb. from China was converted to the p-nitrophenyl esters, and the esters separated by chromatography. The separated p-nitrophenyl esters were individually hydrolysed by potassium hydroxide in acetone-water at room temperature to 8 diterpene acids of the pimarane and abietane groups: pimaric acid (8(14),15-pimaradien-18-oic acid) (1), levopimaric acid (8(14),12-abietadien-18-oic acid) (2), palustric acid (8,13-abietadien-18-oic acid) (3), neobietic acid (8(14),13(15)-abietadien-18-oic acid) (4), abietic acid (7,13-abietadien-18-oic acid) (5), dehydroabietic acid (8,11,13-abietatrien-18-oic acid) (6), 7-oxodehydroabietic acid (7-oxo-8,11,13-abietatrien-18-oic acid) (7) and 7 alpha-hydroxydehydroabietic acid (7 alpha-hydroxy-8,11,13-abietatrien-18-oic acid) (8). The structure (and stereochemistry) of the diterpene acids were substantiated by nuclear magnetic resonance spectroscopy (proton and carbon-13, one and two dimensional), by mass spectrometry (electron impact and methane chemical ionization) and by rotation measurements. The 8 diterpene acids were tested for their ability to inhibit the aggregation of washed rabbit platelets induced by platelet activating factor (PAF), adenosine diphosphate (ADP) and by calcium ionophore A23187. With platelet aggregation induced by the latter two agonists, activities comparable with or higher than linolenic acid were given by the first 4 acids. With aggregation induced by PAF, the first 3 acids show activity, but at a level significantly lower than that of linolenic acid. Levopimaric acid has the highest activity among the diterpene acids tested. It is proposed that this activity is related to the folded shape of the molecule.

  15. Adsorption Equilibrium Equation of Carboxylic Acids on Anion-Exchange Resins in Water.

    Science.gov (United States)

    Kanazawa, Nobuhiro; Urano, Kohei; Kokado, Naohiro; Urushigawa, Yoshikuni

    2001-06-01

    The adsorption of propionic acid and benzoic acid on anion-exchange resins was analyzed, and an adsorption equilibrium equation of carboxylic acids was proposed. The adsorption of carboxylic acids on the anion-exchange resins was considered to be the sum of the physical adsorption of the molecule and the ion-exchange adsorption of the ion, which were independent of each other. For the physical adsorption of carboxylic acids, it was conformed to the Freundlich equation. For the ion-exchange adsorption of carboxylate ions, the equilibrium equation corresponded well with the experimental results for wide ranges of concentration and pH. The equation contains a selectivity coefficient S(A)(Cl) for the chloride ion versus the carboxylate ion, which was considered essentially a constant. The influent of the bicarbonate ion from carbon dioxide in air could also be expressed by the additional equilibrium equation with the selectivity coefficient S(HCO(3))(Cl) for the chloride ion versus the bicarbonate ion. Consequently, an adsorption equilibrium equation can estimate the equilibrium adsorption amounts. Even the effect of a coexisting bicarbonate ion is inconsequential when the parameters of the Freundlich isotherm equation and the selectivity coefficients of the carboxylate ion and the bicarbonate ion in each resin are determined in advance. Copyright 2001 Academic Press.

  16. Study of plutonium IV elution from macromolecular anion exchange resin by 0.5 M nitric acid

    International Nuclear Information System (INIS)

    Nadkarni, M.N.; Mayankutty, P.C.; Pillai, N.S.; Shinde, S.S.

    1976-01-01

    Preliminary studies indicated that macroreticular resins possess more or less the same capacities and absorption characteristics for thorium, uranium and plutonium from nitric acid solutions as the conventional resins. Detailed studies were, then, conducted. It was found that Pu(IV) can be loaded on the macroreticular anion exchange resin, Amberlyst A-26 from 7.2 M nitric acid in much the same way as Dowex 1x4. It was also observed that the elution of Pu(IV) from Amberlyst A-26 by 0.5 M nitric acid is much more rapid and quantitative than from Dowex 1x4. (author)

  17. Oleanolic acid and ursolic acid inhibit peptidoglycan biosynthesis in Streptococcus mutans UA159

    Directory of Open Access Journals (Sweden)

    Soon-Nang Park

    2015-06-01

    Full Text Available In this study, we revealed that OA and UA significantly inhibited the expression of most genes related to peptidoglycan biosynthesis in S. mutans UA159. To the best of our knowledge, this is the first report to introduce the antimicrobial mechanism of OA and UA against S. mutans.

  18. Nitric oxide metabolism and indole acetic acid biosynthesis cross-talk in Azospirillum brasilense SM.

    Science.gov (United States)

    Koul, Vatsala; Tripathi, Chandrakant; Adholeya, Alok; Kochar, Mandira

    2015-04-01

    Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase (nosZ), nitrous oxide reductase regulator (nosR) and nitric oxide reductase (norB) were identified in the plant-associated bacterium (PAB) Azospirillum brasilense SM. NO presence was confirmed in all overexpressing strains, while improvement in the plant growth response of these strains was mediated by increased NO and indole-3-acetic acid (IAA) levels in the strains. Electron microscopy showed random distribution to biofilm, with surface colonization of pleiomorphic Azospirilla. Quantitative IAA estimation highlighted a crucial role of nosR and norBC in regulating IAA biosynthesis. The NO quencher and donor reduced/blocked IAA biosynthesis by all strains, indicating their common regulatory role in IAA biosynthesis. Tryptophan (Trp) and l-Arginine (Arg) showed higher expression of NO genes tested, while in the case of ipdC, only Trp and IAA increased expression, while Arg had no significant effect. The highest nosR expression in SMnosR in the presence of IAA and Trp, along with its 2-fold IAA level, confirmed the relationship of nosR overexpression with Trp in increasing IAA. These results indicate a strong correlation between IAA and NO in A. brasilense SM and suggest the existence of cross-talk or shared signaling mechanisms in these two growth regulators. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  19. Biosynthesis of Polyunsaturated Fatty Acids in Marine Invertebrates: Recent Advances in Molecular Mechanisms

    Science.gov (United States)

    Monroig, Óscar; Tocher, Douglas R.; Navarro, Juan C.

    2013-01-01

    Virtually all polyunsaturated fatty acids (PUFA) originate from primary producers but can be modified by bioconversions as they pass up the food chain in a process termed trophic upgrading. Therefore, although the main primary producers of PUFA in the marine environment are microalgae, higher trophic levels have metabolic pathways that can produce novel and unique PUFA. However, little is known about the pathways of PUFA biosynthesis and metabolism in the levels between primary producers and fish that are largely filled by invertebrates. It has become increasingly apparent that, in addition to trophic upgrading, de novo synthesis of PUFA is possible in some lower animals. The unequivocal identification of PUFA biosynthetic pathways in many invertebrates is complicated by the presence of other organisms within them. These organisms include bacteria and algae with PUFA biosynthesis pathways, and range from intestinal flora to symbiotic relationships that can involve PUFA translocation to host organisms. This emphasizes the importance of studying biosynthetic pathways at a molecular level, and the continual expansion of genomic resources and advances in molecular analysis is facilitating this. The present paper highlights recent research into the molecular and biochemical mechanisms of PUFA biosynthesis in marine invertebrates, particularly focusing on cephalopod molluscs. PMID:24152561

  20. Separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid as eluent.

    Science.gov (United States)

    Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae-Jeong; Lee, Kwang-Pill

    2003-05-16

    The application of various hydrophilic cation-exchange resins for high-performance liquid chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in ion-exclusion chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the ion-exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the ion-exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent.

  1. Nitrate Activation of Cytosolic Protein Kinases Diverts Photosynthetic Carbon from Sucrose to Amino Acid Biosynthesis

    Science.gov (United States)

    Champigny, Marie-Louise; Foyer, Christine

    1992-01-01

    The regulation of carbon partitioning between carbohydrates (principally sucrose) and amino acids has been only poorly characterized in higher plants. The hypothesis that the pathway of sucrose and amino acid biosynthesis compete for carbon skeletons and energy is widely accepted. In this review, we suggest a mechanism involving the regulation of cytosolic protein kinases whereby the flow of carbon is regulated at the level of partitioning between the pathways of carbohydrate and nitrogen metabolism via the covalent modulation of component enzymes. The addition of nitrate to wheat seedlings (Triticum aestivum) grown in the absence of exogenous nitrogen has a dramatic, if transient, impact on sucrose formation and on the activities of sucrose phosphate synthase (which is inactivated) and phosphoenolpyruvate carboxylase (which is activated). The activities of these two enzymes are modulated by protein phosphorylation in response to the addition of nitrate, but they respond in an inverse fashion. Sucrose phosphate synthase in inactivated and phosphoenolpyruvate carboxylase is activated. Nitrate functions as a signal metabolite activating the cytosolic protein kinase, thereby modulating the activities of at least two of the key enzymes in assimilate partitioning and redirecting the flow of carbon away from sucrose biosynthesis toward amino acid synthesis. PMID:16653003

  2. Deficient liver biosynthesis of docosahexaenoic acid correlates with cognitive impairment in Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Giuseppe Astarita

    2010-09-01

    Full Text Available Reduced brain levels of docosahexaenoic acid (C22:6n-3, a neurotrophic and neuroprotective fatty acid, may contribute to cognitive decline in Alzheimer's disease. Here, we investigated whether the liver enzyme system that provides docosahexaenoic acid to the brain is dysfunctional in this disease. Docosahexaenoic acid levels were reduced in temporal cortex, mid-frontal cortex and cerebellum of subjects with Alzheimer's disease, compared to control subjects (P  =  0.007. Mini Mental State Examination (MMSE scores positively correlated with docosahexaenoic/α-linolenic ratios in temporal cortex (P =  0.005 and mid-frontal cortex (P  =  0.018, but not cerebellum. Similarly, liver docosahexaenoic acid content was lower in Alzheimer's disease patients than control subjects (P  =  0.011. Liver docosahexaenoic/α-linolenic ratios correlated positively with MMSE scores (r  =  0.78; P<0.0001, and negatively with global deterioration scale grades (P  =  0.013. Docosahexaenoic acid precursors, including tetracosahexaenoic acid (C24:6n-3, were elevated in liver of Alzheimer's disease patients (P  =  0.041, whereas expression of peroxisomal d-bifunctional protein, which catalyzes the conversion of tetracosahexaenoic acid into docosahexaenoic acid, was reduced (P  = 0.048. Other genes involved in docosahexaenoic acid metabolism were not affected. The results indicate that a deficit in d-bifunctional protein activity impairs docosahexaenoic acid biosynthesis in liver of Alzheimer's disease patients, lessening the flux of this neuroprotective fatty acid to the brain.

  3. Auxin-Induced Ethylene Triggers Abscisic Acid Biosynthesis and Growth Inhibition1

    Science.gov (United States)

    Hansen, Hauke; Grossmann, Klaus

    2000-01-01

    The growth-inhibiting effects of indole-3-acetic acid (IAA) at high concentration and the synthetic auxins 7-chloro-3-methyl-8-quinolinecarboxylic acid (quinmerac), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 4-amino-3,6,6-trichloropicolinic acid (picloram), and naphthalene acetic acid, were investigated in cleavers (Galium aparine). When plants were root treated with 0.5 mm IAA, shoot epinasty and inhibition of root and shoot growth developed during 24 h. Concomitantly, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity, and ACC and ethylene production were transiently stimulated in the shoot tissue within 2 h, followed by increases in immunoreactive (+)-abscisic acid (ABA) and its precursor xanthoxal (xanthoxin) after 5 h. After 24 h of treatment, levels of xanthoxal and ABA were elevated up to 2- and 24-fold, relative to control, respectively. In plants treated with IAA, 7-chloro-3-methyl-8-quinolinecarboxylic acid, naphthalene acetic acid, 2-methoxy-3,6-dichlorobenzoic acid, and 4-amino-3,6,6-trichloropicolinic acid, levels of ethylene, ACC, and ABA increased in close correlation with inhibition of shoot growth. Aminoethoxyvinyl-glycine and cobalt ions, which inhibit ethylene synthesis, decreased ABA accumulation and growth inhibition, whereas the ethylene-releasing ethephon promoted ABA levels and growth inhibition. In accordance, tomato mutants defective in ethylene perception (never ripe) did not produce the xanthoxal and ABA increases and growth inhibition induced by auxins in wild-type plants. This suggests that auxin-stimulated ethylene triggers ABA accumulation and the consequent growth inhibition. Reduced catabolism most probably did not contribute to ABA increase, as indicated by immunoanalyses of ABA degradation and conjugation products in shoot tissue and by pulse experiments with [3H]-ABA in cell suspensions of G. aparine. In contrast, studies using inhibitors of ABA biosynthesis (fluridone, naproxen, and tungstate), ABA

  4. Biosynthesis of caffeic acid in Escherichia coli using its endogenous hydroxylase complex

    Science.gov (United States)

    2012-01-01

    Background Caffeic acid (3,4-dihydroxycinnamic acid) is a natural phenolic compound derived from the plant phenylpropanoid pathway. Caffeic acid and its phenethyl ester (CAPE) have attracted increasing attention for their various pharmaceutical properties and health-promoting effects. Nowadays, large-scale production of drugs or drug precursors via microbial approaches provides a promising alternative to chemical synthesis and extraction from plant sources. Results We first identified that an Escherichia coli native hydroxylase complex previously characterized as the 4-hydroxyphenylacetate 3-hydroxylase (4HPA3H) was able to convert p-coumaric acid to caffeic acid efficiently. This critical enzymatic step catalyzed in plants by a membrane-associated cytochrome P450 enzyme, p-coumarate 3-hydroxylase (C3H), is difficult to be functionally expressed in prokaryotic systems. Moreover, the performances of two tyrosine ammonia lyases (TALs) from Rhodobacter species were compared after overexpression in E. coli. The results indicated that the TAL from R. capsulatus (Rc) possesses higher activity towards both tyrosine and L-dopa. Based on these findings, we further designed a dual pathway leading from tyrosine to caffeic acid consisting of the enzymes 4HPA3H and RcTAL. This heterologous pathway extended E. coli native tyrosine biosynthesis machinery and was able to produce caffeic acid (12.1 mg/L) in minimal salt medium. Further improvement in production was accomplished by boosting tyrosine biosynthesis in E. coli, which involved the alleviation of tyrosine-induced feedback inhibition and carbon flux redirection. Finally, the titer of caffeic acid reached 50.2 mg/L in shake flasks after 48-hour cultivation. Conclusion We have successfully established a novel pathway and constructed an E. coli strain for the production of caffeic acid. This work forms a basis for further improvement in production, as well as opens the possibility of microbial synthesis of more complex plant

  5. Biosynthesis of caffeic acid in Escherichia coli using its endogenous hydroxylase complex

    Directory of Open Access Journals (Sweden)

    Lin Yuheng

    2012-04-01

    Full Text Available Abstract Background Caffeic acid (3,4-dihydroxycinnamic acid is a natural phenolic compound derived from the plant phenylpropanoid pathway. Caffeic acid and its phenethyl ester (CAPE have attracted increasing attention for their various pharmaceutical properties and health-promoting effects. Nowadays, large-scale production of drugs or drug precursors via microbial approaches provides a promising alternative to chemical synthesis and extraction from plant sources. Results We first identified that an Escherichia coli native hydroxylase complex previously characterized as the 4-hydroxyphenylacetate 3-hydroxylase (4HPA3H was able to convert p-coumaric acid to caffeic acid efficiently. This critical enzymatic step catalyzed in plants by a membrane-associated cytochrome P450 enzyme, p-coumarate 3-hydroxylase (C3H, is difficult to be functionally expressed in prokaryotic systems. Moreover, the performances of two tyrosine ammonia lyases (TALs from Rhodobacter species were compared after overexpression in E. coli. The results indicated that the TAL from R. capsulatus (Rc possesses higher activity towards both tyrosine and L-dopa. Based on these findings, we further designed a dual pathway leading from tyrosine to caffeic acid consisting of the enzymes 4HPA3H and RcTAL. This heterologous pathway extended E. coli native tyrosine biosynthesis machinery and was able to produce caffeic acid (12.1 mg/L in minimal salt medium. Further improvement in production was accomplished by boosting tyrosine biosynthesis in E. coli, which involved the alleviation of tyrosine-induced feedback inhibition and carbon flux redirection. Finally, the titer of caffeic acid reached 50.2 mg/L in shake flasks after 48-hour cultivation. Conclusion We have successfully established a novel pathway and constructed an E. coli strain for the production of caffeic acid. This work forms a basis for further improvement in production, as well as opens the possibility of microbial synthesis

  6. Bonding effectiveness of self-adhesive and conventional-type adhesive resin cements to CAD/CAM resin blocks. Part 2: Effect of ultrasonic and acid cleaning.

    Science.gov (United States)

    Kawaguchi, Asuka; Matsumoto, Mariko; Higashi, Mami; Miura, Jiro; Minamino, Takuya; Kabetani, Tomoshige; Takeshige, Fumio; Mine, Atsushi; Yatani, Hirofumi

    2016-01-01

    The present study assessed the effect of ultrasonic and acid cleaning on resin cement bonding to CAD/CAM resin blocks. One of two resin cements, PANAVIA V5 (PV5) or PANAVIA SA CEMENT HANDMIX (PSA), were bonded to one of 24 CAD/CAM blocks (KATANA AVENCIA BLOCK). Each cement group was divided into four subgroups: no cleaning (Ctl), ultrasonic cleaning (Uc), acid cleaning (Ac) and Uc+Ac. Micro-tensile bond strengths (µTBSs) were measured immediately and 1, 3, and 6 months after water storage. Block surfaces after each treatment were analyzed by scanning electron microscopy. Analysis of variance revealed a statistically significant effect for the parameters 'surface treatment' (p<0.001, F=40), 'resin cement' (p<0.001, F=696) and 'water aging' (p<0.001, F=71). The PV5 group exhibited higher µTBS values than the PSA group. Although cleaning after sandblasting was effective in removing residual alumina particles, it did not affect the long-term bonding durability with non-contaminated CAD/CAM resin blocks.

  7. Aminolysis of resin-bound N-nosylaziridine-2-carboxylic acids

    DEFF Research Database (Denmark)

    Olsen, Christian A; Christensen, Caspar; Nielsen, Birgitte

    2006-01-01

    [Structure: see text] Solid-phase synthesis is a rapidly developing area of organic chemistry, of particular importance for medicinal chemistry and chemical biology. Aziridines have previously only rarely been applied in solid-phase synthesis. In the present work, aminolysis of resin-bound, spring......-loaded N-nitrobenzenesulfonyl-activated aziridine-2-carboxylic acids has been optimized and employed in the synthesis of a number of open-chain and heterocyclic scaffolds, including enantiopure products....

  8. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  9. Screening Analyses of Pinosylvin Stilbenes, Resin Acids and Lignans in Norwegian Conifers

    Directory of Open Access Journals (Sweden)

    Anne Fiksdahl

    2006-01-01

    Full Text Available The content and distribution of stilbenes and resin acids in Scots pine (Pinus sylvestris and spruce (Picea abies, sampled in central Norway, have been examined. The contents of pinosylvin stilbenes in pine heartwood/living knots were 0.2-2/2-8 % (w/w. No stilbenes could be detected in spruce (Picea abies. The resin acid contents of pine sapwood/heartwood and knots were 1-4 and 5-10 % (w/w, respectively. Minor amounts of resin acids (< 0.2/< 0.04 %w/w were identified in spruce wood/knots. The lignan content in knots of Norwegian spruce was 6.5 % (w/w. Diastereomerically pure hydroxymatairesinol (HMR, 84 % of total lignans was readily isolated from this source since only minor quantities (2.6 % of total lignans of the allo-HMR diastereomer was detected. Insignificant amounts of lignans were present in the sapwood. Lignans could not be detected in the sapwood or knots of Norwegian sallow (Salix caprea, birch (Betula pendula or juniper (Juniperus communis.

  10. Removing and recovering of uranium from the acid mine waters by using ion exchange resin

    International Nuclear Information System (INIS)

    Nascimento, Marcos Roberto Lopes do

    1998-01-01

    Ion exchange using resins is one of the few processes capable of reducing ionic contaminants in effluents to very low levels. In this study the process was used to remove and recovery uranium from acid mine waters at Pocos de Caldas-MG Uranium Mining and Milling Plant. The local mineralogical features, allied to the biogeochemical phenomena, owing to presence of pyrite in the rock piles, moreover another factors, resulting acid drainage with several pollutants, including uranium ranging from 6 to 14 mg/l, as sulfate complex, that can be removed by anionic exchanger. The iron interference is eliminated by lime pretreatment of water, increasing pH from 2.6 to 3.3-3.8 to precipitate this cation, without changing the uranium amount. Eight anionic resins were tested, based on the uranium loading, in sorption studies. Retention time, and pH influence was verified for the exchanger chose. With breakthrough of 1 mg U/L and 10 mg U/l in the feed solution, the uranium decontamination level was 94%. Typical values of loading resin were 20-30 g U/l and 70-90 g SO 4 /l. Uranium elution was done with Na Cl solution. Retention time, saline, and acid concentration were the parameters studied. The concentrate, obtained from the eluate by ammonia precipitation, presented uranium (86,8% as U 3 O 8 ) and impurities within commercial specifications. (author)

  11. Synthesis of iminodi(methylphosphonic acid)-type chitosan resin and its adsorption behavior for trace metals

    International Nuclear Information System (INIS)

    Yamakawa, Satoko; Oshita, Koji; Sabarudin, Akhmad; Oshima, Mitsuko; Motomizu, Shoji

    2004-01-01

    A chitosan-based resin possessing the iminodi(methyphosphonic acid) moiety (IDP-type chitrosan resin) was synthesized by using cross-linked chitosan as a base material. The adsorption behavior of trace metal ions on the IDP-type chitosan resin was systematically investigated using a mini-column (1 ml of the resin) packed with the resin. The concentrations of metal ions in the effluents were measured by ICP-MS and ICP-AES. The resin could adsorb four metals, such as In(III), Sn(II), Th(IV), and U(VI), by almost 100% over a wide pH range (1-7). Uranium(VI) and thorium could not be eluted with nitric acid and hydrochloric acid (1-6 M); other metal ions were easily and readily eluted with 1 M nitric acid. The IDP-type chitosan resin synthesized in this work can be applied to the separation of U(VI) and Th(IV) from other metal ions. (author)

  12. The application of macroporous resins in the separation of licorice flavonoids and glycyrrhizic acid.

    Science.gov (United States)

    Fu, Boqiang; Liu, Jie; Li, Huan; Li, Lei; Lee, Frank S C; Wang, Xiaoru

    2005-09-30

    Glycyrrhizic acid (GA) and licorice flavonoids (LF) are the two classes of bioactive components in licorice with known pharmacological effects. But long-term excessive intake of GA may cause sodium retention and hypertension. In this study, the performance and adsorption characteristics of four widely used macroporous resins for the separation of deglycyrrhizinated, flavonoids enriched licorice has been critically evaluated. The sorption and desorption properties of LF and GA on macroporous resins including XDA-1, LSA-10, D101 and LSA-20 have been compared. The adsorption capacity was found to depend strongly on the pH of the feed solution. XDA-1 offers much higher adsorption capacity for GA and LF than other resins, and its adsorption data fit the best to the Freundlich isotherm. XDA-1 also shows much higher adsorption affinity towards LF than that of GA based on calculated results from the measured adsorption isotherms. Dynamic adsorption and desorption experiments have been carried out on a XDA-1 resin packed column to obtain optimal parameters for separating GA and LF. An enriched LF extract (about 21.9% purity) free of GA, and an enriched GA extract with 66% purity can be separated from crude licorice extract in one run.

  13. Effect of humic acid on ciprofloxacin removal by magnetic multifunctional resins

    Science.gov (United States)

    Wang, Wei; Cheng, Jiade; Jin, Jing; Zhou, Qing; Ma, Yan; Zhao, Qingqing; Li, Aimin

    2016-07-01

    Background organic matter significantly influences the removal of emerging contaminants in natural water. In this work, the adsorption of ciprofloxacin (CPX) onto a series of magnetic multifunctional resins (GMA10-GMA90) in the presence and absence of humic acid (HA) was conducted to demonstrate the effect of HA. Both hydrophobic and ion exchange interactions contributed to CPX adsorption. Negative charge-assisted hydrogen bonds also participated in the adsorption process, resulting in the high adsorption amount of anionic CPX onto the negatively charged GMA30 under basic solutions. HA could impact CPX adsorption not only as a competitive adsorbate but also as an additional adsorbent. At pH 5.6, the additional adsorption sites provided by adsorbed HA molecules on the resins dominated and thus facilitated the adsorption process. While at pH 10, HA inhibited the adsorption of CPX by directly competing for ion exchange sites and coexisting with CPX in the solution. The ratio of the amount of CPX adsorbed by dissolved HA to that by the resin reached as high as 1.61 for GMA90. The adsorbed HA molecules onto the resins could provide additional adsorption sites for CPX as proven by the enhanced CPX adsorption in HA-preloading systems at pH 5.6.

  14. Oxidative degradation of low and intermediate level Radioactive organic wastes 2. Acid decomposition on spent Ion-Exchange resins

    International Nuclear Information System (INIS)

    Ghattas, N.K.; Eskander, S.B.

    1995-01-01

    The present work provides a simplified, effective and economic method for the chemical decomposition of radioactively contaminated solid organic waste, especially spent ion - exchange resins. The goal is to achieve volume reduction and to avoid technical problems encountered in processes used for similar purposes (incineration, pyrolysis). Factors efficiency and kinetics of the oxidation of the ion exchange resins in acid medium using hydrogen peroxide as oxidant, namely, duration of treatment and the acid to resin ratio were studied systematically on a laboratory scale. Moreover the percent composition of the off-gas evolved during the decomposition process was analysed. 3 figs., 5 tabs

  15. Metazoan Remaining Genes for Essential Amino Acid Biosynthesis: Sequence Conservation and Evolutionary Analyses

    Directory of Open Access Journals (Sweden)

    Igor R. Costa

    2014-12-01

    Full Text Available Essential amino acids (EAA consist of a group of nine amino acids that animals are unable to synthesize via de novo pathways. Recently, it has been found that most metazoans lack the same set of enzymes responsible for the de novo EAA biosynthesis. Here we investigate the sequence conservation and evolution of all the metazoan remaining genes for EAA pathways. Initially, the set of all 49 enzymes responsible for the EAA de novo biosynthesis in yeast was retrieved. These enzymes were used as BLAST queries to search for similar sequences in a database containing 10 complete metazoan genomes. Eight enzymes typically attributed to EAA pathways were found to be ubiquitous in metazoan genomes, suggesting a conserved functional role. In this study, we address the question of how these genes evolved after losing their pathway partners. To do this, we compared metazoan genes with their fungal and plant orthologs. Using phylogenetic analysis with maximum likelihood, we found that acetolactate synthase (ALS and betaine-homocysteine S-methyltransferase (BHMT diverged from the expected Tree of Life (ToL relationships. High sequence conservation in the paraphyletic group Plant-Fungi was identified for these two genes using a newly developed Python algorithm. Selective pressure analysis of ALS and BHMT protein sequences showed higher non-synonymous mutation ratios in comparisons between metazoans/fungi and metazoans/plants, supporting the hypothesis that these two genes have undergone non-ToL evolution in animals.

  16. Effects of ionizing radiation on the activity of the major hepatic enzymes implicated in bile acid biosynthesis in the rat

    International Nuclear Information System (INIS)

    Souidi, M.; Scanff, P.; Grison, St.; Gourmelon, P.; Aigueperse, J.

    2007-01-01

    In the days following high-dose radiation exposure, damage to small intestinal mucosa is aggravated by changes in the bile acid pool reaching the gut. Intestinal bile acid malabsorption, as described classically, may be associated with altered hepatic bile acid biosynthesis, which was the objective of this work. The activity of the main rate-limiting enzymes implicated in the bile acid biosynthesis were evaluated in the days following an 8-Gy γ Co 60 total body irradiation of rats, with concomitant determination of biliary bile acid profiles and intestinal bile acid content. Modifications of biliary bile acid profiles, observed as early as the first post-irradiation day, were most marked at the third and fourth day, and resulted in an increased hydrophobicity index. In parallel, the intestinal bile acids' content was enhanced and hepatic enzymatic activities leading to bile acids were changed. A marked increase of sterol 12-hydroxylase and decrease of oxy-sterol 7-hydroxylase activity was observed at day 3, whereas both cholesterol 7-hydroxylase and oxy-sterol 7-hydroxylase activities were decreased at day 4 after irradiation. These results show, for the first time, radiation-induced modifications of hepatic enzymatic activities implicated in bile acid biosynthesis and suggest that they are mainly a consequence of radiation-altered intestinal absorption, which induces a physiological response of the entero-hepatic bile acid recirculation. (authors)

  17. SPE and HPLC/UV of resin acids in colophonium-containing products.

    Science.gov (United States)

    Nilsson, Ulrika; Berglund, Naghmeh; Lindahl, Fredrik; Axelsson, Sara; Redeby, Theres; Lassen, Pia; Karlberg, Ann-Therese

    2008-08-01

    A new method, involving SPE and HPLC/UV diode-array detection (DAD), was developed for the quantification of colophonium components in different consumer products, such as cosmetics. Colophonium is a common cause of contact dermatitis since its components can oxidize into allergens on exposure to air. Three different resin acids were used as markers for native and oxidized colophonium, abietic acid (AbA), dehydroabietic acid (DeA), and 7-oxodehydroabietic acid (7-O-DeA). The SPE method, utilizing a mixed-mode hydrophobic and anion exchange retention mechanism, was shown to yield very clean extracts. The use of a urea-embedded C(12) HPLC stationary phase improved the separation of the resin acids compared to common C(18). Concentrations higher than 2 mg/g of both AbA and DeA were detected in wax strips. In this product also 7-O-DeA, a marker for oxidized colophonium, was detected at a level of 28 microg/g. The LODs were in the range of 7-19 microg/g and the LOQs 22-56 microg/g. The method is simple to use and can be applied on many types of technical products, not only cosmetics. For the first time, a method for technical products was developed, which separates AbA from pimaric acid.

  18. The Catalytic Machinery of a Key Enzyme in Amino Acid Biosynthesis

    Directory of Open Access Journals (Sweden)

    Ronald E. Viola

    2011-01-01

    Full Text Available The aspartate pathway of amino acid biosynthesis is essential for all microbial life but is absent in mammals. Characterizing the enzyme-catalyzed reactions in this pathway can identify new protein targets for the development of antibiotics with unique modes of action. The enzyme aspartate β-semialdehyde dehydrogenase (ASADH catalyzes an early branch point reaction in the aspartate pathway. Kinetic, mutagenic, and structural studies of ASADH from various microbial species have been used to elucidate mechanistic details and to identify essential amino acids involved in substrate binding, catalysis, and enzyme regulation. Important structural and functional differences have been found between ASADHs isolated from these bacterial and fungal organisms, opening the possibility for developing species-specific antimicrobial agents that target this family of enzymes.

  19. The Catalytic Machinery of a Key Enzyme in Amino Acid Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Viola, Ronald E.; Faehnle, Christopher R.; Blanco, Julio; Moore, Roger A.; Liu, Xuying; Arachea, Buenafe T.; Pavlovsky, Alexander G. (Toledo); (Yale); (Cold Spring); (NIH)

    2013-02-28

    The aspartate pathway of amino acid biosynthesis is essential for all microbial life but is absent in mammals. Characterizing the enzyme-catalyzed reactions in this pathway can identify new protein targets for the development of antibiotics with unique modes of action. The enzyme aspartate {beta}-semialdehyde dehydrogenase (ASADH) catalyzes an early branch point reaction in the aspartate pathway. Kinetic, mutagenic, and structural studies of ASADH from various microbial species have been used to elucidate mechanistic details and to identify essential amino acids involved in substrate binding, catalysis, and enzyme regulation. Important structural and functional differences have been found between ASADHs isolated from these bacterial and fungal organisms, opening the possibility for developing species-specific antimicrobial agents that target this family of enzymes.

  20. Design and synthesis of bio-based UV curable PU acrylate resin from itaconic acid for coating applications.

    Science.gov (United States)

    Patil, Deepak M; Phalak, Ganesh A; Mhaske, S T

    2017-01-01

    UV curable PUA resin was successfully synthesized from polyol based on sustainable resource originated from itaconic acid (IA), isophorone diisocyanate (IPDI) and 2-hydroxyethyl methacrylate (HEMA). A polyol was synthesized by condensation reaction of IA with 16-hexanediol in the presence of p-Toluenesulfonic acid (pTSA). The synthesized PUA resin was characterized for its structural elucidation by using Fourier Transform Infrared Spectrophotometer (FTIR), 1 H and 13 C NMR spectroscopy. The synthesized UV curable PUA resin was incorporated in varying concentrations in conventional PUA coating system. The effects of varying concentration of synthesized UV curable PUA resin on rheology, crystallinity, thermal and coating properties were evaluated. The rheological behavior of the resins were evaluated at variable stress and result showed decrease in viscosity of resin as concentration of synthesized UV curable PUA resin increases in conventional PUA resin. The cured coatings have been evaluated for glass transition temperature ( T g ) and thermal behavior by differential scanning calorimeter and thermogravimetric analysis respectively. The degree of crystallinity of the coatings was determined from X-ray diffraction patterns using the PFM program. It was found that increase in the mass proportion of IA based PUA in coatings, the coating becomes more rigid and crystalline. The synthesized UV curable PUA coatings showed interesting mechanical, chemical, solvent and thermal properties as compared to the conventional PUA. Further, cured coatings were also evaluated for gel content and water absorption.

  1. Reduced macrophage selenoprotein expression alters oxidized lipid metabolite biosynthesis from arachidonic and linoleic acid.

    Science.gov (United States)

    Mattmiller, Sarah A; Carlson, Bradley A; Gandy, Jeff C; Sordillo, Lorraine M

    2014-06-01

    Uncontrolled inflammation is an underlying etiology for multiple diseases and macrophages orchestrate inflammation largely through the production of oxidized fatty acids known as oxylipids. Previous studies showed that selenium (Se) status altered the expression of oxylipids and magnitude of inflammatory responses. Although selenoproteins are thought to mediate many of the biological effects of Se, the direct effect of selenoproteins on the production of oxylipids is unknown. Therefore, the role of decreased selenoprotein activity in modulating the production of biologically active oxylipids from macrophages was investigated. Thioglycollate-elicited peritoneal macrophages were collected from wild-type and myeloid-cell-specific selenoprotein knockout mice to analyze oxylipid production by liquid chromatography/mass spectrometry as well as oxylipid biosynthetic enzyme and inflammatory marker gene expression by quantitative real-time polymerase chain reaction. Decreased selenoprotein activity resulted in the accumulation of reactive oxygen species, enhanced cyclooxygenase and lipoxygenase expression and decreased oxylipids with known anti-inflammatory properties such as arachidonic acid-derived lipoxin A₄ (LXA₄) and linoleic acid-derived 9-​oxo-octadecadienoic acid (9-oxoODE). Treating RAW 264.7 macrophages with LXA₄ or 9-oxoODE diminished oxidant-induced macrophage inflammatory response as indicated by decreased production of TNFα. The results show for the first time that selenoproteins are important for the balanced biosynthesis of pro- and anti-inflammatory oxylipids during inflammation. A better understanding of the Se-dependent control mechanisms governing oxylipid biosynthesis may uncover nutritional intervention strategies to counteract the harmful effects of uncontrolled inflammation due to oxylipids. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Studies of transformation and particle-binding of resin acids during oxidative treatment of effluent from two New Zealand pulp mills.

    Science.gov (United States)

    Kanber, S A; Langdon, A G; Wilkins, A L

    2008-02-01

    Reactor studies of aerobic degradation of effluent from the first and last ponds of the treatment system of two New Zealand pulp and paper mills indicated that filterable BOD(5), resin acids and transformed resin acids, free and bound, degraded at similar rates. During oxidative treatment the resin acids of untreated effluent became increasingly bound to particulate material and a sediment high in abiet-13-enoic acid was formed.

  3. The Use of Commercial Non-Hazardous Air Pollutant Monomers to Optimize the Properties of Fatty Acid-Based Resins

    Science.gov (United States)

    2009-05-01

    It was found that cyclohexyl methacrylate (CHMA) was the most effective reactive diluent in replacing methacrylated lauric acid (MLau) because it...The reaction of glycidyl methacrylate and lauric acid to produce the MLau monomer... acid -based monomers to be used as the reactive diluent in VE resins (9, 10). Figure 1 depicts the synthetic route used to form methacrylated lauric

  4. Research on the ability of propionic acid and vitamin B12 biosynthesis by Propionibacterium freudenreichii strain T82.

    Science.gov (United States)

    Piwowarek, Kamil; Lipińska, Edyta; Hać-Szymańczuk, Elżbieta; Bzducha-Wróbel, Anna; Synowiec, Alicja

    2017-11-25

    The purpose of this study was to determine the potential for biosynthesis of propionic acid and vitamin B12 by Propionibacterium freudenreichii T82 in a medium containing various sources of carbon (glucose, fructose, and saccharose). These sugars are present in apple pomaces, which are the waste from the production of apple juice. Using statistical analysis design of experiments (DoE), the results allowed us to determine which sugars (carbon sources) exert the most beneficial influence on the biosynthesis of propionic acid and cobalamin. The highest production of propionic acid by the tested bacterial strain was obtained in a medium in which glucose accounted for at least 50% of the available carbon sources. Depending on the culture medium, the concentration of this metabolite ranged from 23 to 40 g/L. P. freudenreichii T82 produced the smallest amount of acid in medium in which the dominant nutrient source was saccharose. The results obtained indicated an inverse relationship between the amount of acid produced by the bacteria and vitamin B12 biosynthesis. Because of the high efficiency of propionic acid biosynthesis by P. freudenreichii T82, the prospect of using this strain to obtain propionate with the simultaneous disposal of waste materials (such as apple pomaces) which contain glucose and/or fructose is very promising.

  5. Biogenic glutamic acid-based resin: Its synthesis and application in the removal of cobalt(II)

    Energy Technology Data Exchange (ETDEWEB)

    Jamiu, Zakariyah A.; Saleh, Tawfik A.; Ali, Shaikh A., E-mail: shaikh@kfupm.edu.sa

    2017-04-05

    Highlights: • A novel resin embedded with metal chelating glutamic acid was synthesized. • The biogenic amino acid residues imparted remarkable efficacy to remove Co(II). • The resin showed excellent ability to remove various metals from wastewater. - Abstract: Inexpensive biogenic glutamic acid has been utilized to synthesize a cross-linked dianionic polyelectrolyte (CDAP) containing metal chelating ligands. Cycloterpolymerization, using azoisobutyronitrile as an initiator, of N,N-diallylglutamic acid hydrochloride, sulfur dioxide and a cross-linker afforded a pH-responsive cross-linked polyzwitterionic acid (CPZA) which upon basification with NaOH was converted into CDAP. The new resin, characterized by a multitude of spectroscopic techniques as well as Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) analyses, was evaluated for the removal of Co(II) as a model case under different conditions. The adsorption capacity of 137 mg g{sup −1} does indeed make the resin as one of the most effective sorbents in recent times. The resin leverages its cheap natural source and ease of regeneration in combination with its high and fast uptake capacities to offer a great promise for wastewater treatment. The resin has demonstrated remarkable efficiency in removing toxic metal ions including arsenic from a wastewater sample.

  6. Biogenic glutamic acid-based resin: Its synthesis and application in the removal of cobalt(II)

    International Nuclear Information System (INIS)

    Jamiu, Zakariyah A.; Saleh, Tawfik A.; Ali, Shaikh A.

    2017-01-01

    Highlights: • A novel resin embedded with metal chelating glutamic acid was synthesized. • The biogenic amino acid residues imparted remarkable efficacy to remove Co(II). • The resin showed excellent ability to remove various metals from wastewater. - Abstract: Inexpensive biogenic glutamic acid has been utilized to synthesize a cross-linked dianionic polyelectrolyte (CDAP) containing metal chelating ligands. Cycloterpolymerization, using azoisobutyronitrile as an initiator, of N,N-diallylglutamic acid hydrochloride, sulfur dioxide and a cross-linker afforded a pH-responsive cross-linked polyzwitterionic acid (CPZA) which upon basification with NaOH was converted into CDAP. The new resin, characterized by a multitude of spectroscopic techniques as well as Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) analyses, was evaluated for the removal of Co(II) as a model case under different conditions. The adsorption capacity of 137 mg g −1 does indeed make the resin as one of the most effective sorbents in recent times. The resin leverages its cheap natural source and ease of regeneration in combination with its high and fast uptake capacities to offer a great promise for wastewater treatment. The resin has demonstrated remarkable efficiency in removing toxic metal ions including arsenic from a wastewater sample.

  7. Esterification of palm fatty acid distillate with epychlorohydrin using cation exchange resin catalyst

    Science.gov (United States)

    Budhijanto, Budhijanto; Subagyo, Albertus F. P. H.

    2017-05-01

    Palm Fatty Acid Distillate (PFAD) is one of the wastes from the conversion of crude palm oil (CPO) into cooking oil. The PFAD is currently only utilized as the raw material for low grade soap and biofuel. To improve the economic value of PFAD, it was converted into monoglyceride by esterification process. Furthermore, the monoglyceride could be polymerized to form alkyd resin, which is a commodity of increasing importance. This study aimed to propose a kinetics model for esterification of PFAD with epichlorohydrin using cation exchange resin catalyst. The reaction was the first step from a series of reactions to produce the monoglyceride. In this study, the reaction between PFAD and epichlorohydirne was run in a stirred batch reactor. The stirrer was operated at a constant speed of 400 RPM. The reaction was carried out for 180 minutes on varied temperatures of 60°C, 70°C, 80°C, dan 90°C. Cation exchange resin was applied as solid catalysts. Analysis was conducted periodically by measuring the acid number of the samples, which was further used to calculate PFAD conversion. The data were used to determine the rate constants and the equilibrium constants of the kinetics model. The kinetics constants implied that the reaction was reversible and controlled by the intrinsic surface reaction. Despite the complication of the heterogeneous nature of the reaction, the kinetics data well fitted the elementary rate law. The effect of temperature on the equilibrium constants indicated that the reaction is exothermic.

  8. Biodiesel production from acid oils and ethanol using a solid basic resin as catalyst

    International Nuclear Information System (INIS)

    Marchetti, J.M.; Errazu, A.F.

    2010-01-01

    In the search of an alternative fuel to substitute diesel fuel, biodiesel appears as one of the most promising sources of energy for diesel engines because of its environmental advantages and also due to the evolution of the petroleum market. Refined oil is the conventional raw material for the production of this biofuel; however, its major disadvantage is the high cost of its production. Therefore, frying oils, waste oils, crude oils and/or acid oils are being tested as alternative raw materials; nevertheless, there will be some problems if a homogeneous basic catalyst (NaOH) is employed due to the high amount of free fatty acid present in the raw oil. In this work, the transesterification reaction of acid oil using solid resin, Dowex monosphere 550 A, was studied as an alternative process. Ethanol was employed to have a natural and sustainable final product. The reaction temperature's effects, the initial amount of free fatty acid, the molar ratio of alcohol/oil and the type of catalyst (homogeneous or heterogeneous) over the main reaction are analyzed and their effects compared. The results obtained show that the solid resin is an alternative catalyst to be used to produce fatty acid ethyl esters (FAEEs) by a transesterification reaction with a final conversion over 90%. On the other hand, the time required to achieve this conversion is bigger than the one required using conventional technology which employs a homogeneous basic catalyst. This reaction time needs to be optimized. (author)

  9. Cuticle Biosynthesis in Tomato Leaves Is Developmentally Regulated by Abscisic Acid.

    Science.gov (United States)

    Martin, Laetitia B B; Romero, Paco; Fich, Eric A; Domozych, David S; Rose, Jocelyn K C

    2017-07-01

    The expansion of aerial organs in plants is coupled with the synthesis and deposition of a hydrophobic cuticle, composed of cutin and waxes, which is critically important in limiting water loss. While the abiotic stress-related hormone abscisic acid (ABA) is known to up-regulate wax accumulation in response to drought, the hormonal regulation of cuticle biosynthesis during organ ontogeny is poorly understood. To address the hypothesis that ABA also mediates cuticle formation during organ development, we assessed the effect of ABA deficiency on cuticle formation in three ABA biosynthesis-impaired tomato mutants. The mutant leaf cuticles were thinner, had structural abnormalities, and had a substantial reduction in levels of cutin. ABA deficiency also consistently resulted in differences in the composition of leaf cutin and cuticular waxes. Exogenous application of ABA partially rescued these phenotypes, confirming that they were a consequence of reduced ABA levels. The ABA mutants also showed reduced expression of genes involved in cutin or wax formation. This difference was again countered by exogenous ABA, further indicating regulation of cuticle biosynthesis by ABA. The fruit cuticles were affected differently by the ABA-associated mutations, but in general were thicker. However, no structural abnormalities were observed, and the cutin and wax compositions were less affected than in leaf cuticles, suggesting that ABA action influences cuticle formation in an organ-dependent manner. These results suggest dual roles for ABA in regulating leaf cuticle formation: one that is fundamentally associated with leaf expansion, independent of abiotic stress, and another that is drought induced. © 2017 American Society of Plant Biologists. All Rights Reserved.

  10. Insights into the Biosynthesis of 12-Membered Resorcylic Acid Lactones from Heterologous Production in Saccharomyces cerevisiae

    Science.gov (United States)

    2015-01-01

    The phytotoxic fungal polyketides lasiodiplodin and resorcylide inhibit human blood coagulation factor XIIIa, mineralocorticoid receptors, and prostaglandin biosynthesis. These secondary metabolites belong to the 12-membered resorcylic acid lactone (RAL12) subclass of the benzenediol lactone (BDL) family. Identification of genomic loci for the biosynthesis of lasiodiplodin from Lasiodiplodia theobromae and resorcylide from Acremonium zeae revealed collaborating iterative polyketide synthase (iPKS) pairs whose efficient heterologous expression in Saccharomyces cerevisiae provided a convenient access to the RAL12 scaffolds desmethyl-lasiodiplodin and trans-resorcylide, respectively. Lasiodiplodin production was reconstituted in the heterologous host by co-expressing an O-methyltransferase also encoded in the lasiodiplodin cluster, while a glutathione-S-transferase was found not to be necessary for heterologous production. Clarification of the biogenesis of known resorcylide congeners in the heterologous host helped to disentangle the roles that biosynthetic irregularities and chemical interconversions play in generating chemical diversity. Observation of 14-membered RAL homologues during in vivo heterologous biosynthesis of RAL12 metabolites revealed “stuttering” by fungal iPKSs. The close global and domain-level sequence similarities of the orthologous BDL synthases across different structural subclasses implicate repeated horizontal gene transfers and/or cluster losses in different fungal lineages. The absence of straightforward correlations between enzyme sequences and product structural features (the size of the macrocycle, the conformation of the exocyclic methyl group, or the extent of reduction by the hrPKS) suggest that BDL structural variety is the result of a select few mutations in key active site cavity positions. PMID:24597618

  11. Raman spectroscopic study of the aging and nitration of actinide processing anion-exchange resins in concentrated nitric acid

    International Nuclear Information System (INIS)

    Buscher, C. T.; Donohoe, R. J.; Mecklenburg, S. L.; Berg, J. M.; Tait, C. D.; Huchton, K. M.; Morris, D. E.

    1999-01-01

    Degradation of two types of anion exchange resins, Dowex 11 and Reillex HPQ, from the action of concentrated nitric acid (4 to 12 M) and radiolysis [from depleted uranium as UO 2 2+ nitrate species and 239 Pu as Pu(IV) nitrate species] was followed as a function of time with Raman vibrational spectroscopy. Elevated temperatures (∼50 degree sign C) were used in the absence of actinide metal loading to simulate longer exposures of the resin to a HNO 3 process stream and waste storage conditions. In the absence of actinide loading, only minor changes in the Dowex resin at acid concentrations ≤10 M were observed, while at 12 M acid concentration, the emergence of a Raman peak at 1345 cm-1 indicates the addition of nitro functional groups to the resin. Similar studies with the Reillex resin show it to be more resistant to nitric acid attack at all acid concentrations. Incorporation of weakly radioactive depleted uranium as the UO 2 2+ nitrate species to the ion-exchange sites of Dowex 11 under differing nitric acid concentrations (6 to 12 M) at room temperature showed no Raman evidence of resin degradation or nitration, even after several hundred days of contact. In contrast, Raman spectra for Dowex 11 in the presence of 239 Pu as Pu(IV) nitrate species reveal numerous changes indicating resin alterations, including a new mode at 1345 cm-1 consistent with a Pu(IV)-nitrate catalyzed addition of nitro groups to the resin backbone. (c) 2000 Society for Applied Spectroscopy

  12. Developmental changes in aspartate-family amino acid biosynthesis in pea chloroplasts

    International Nuclear Information System (INIS)

    Mills, W.R.; Cato, L.W.; Stephens, B.W.; Reeves, M.

    1990-01-01

    Isolated chloroplasts are known to synthesize the asp-derived amino acids (ile, hse, lys and thr) from [ 14 C]asp (Mills et al, 1980, Plant Physiol. 65, 1166). Now, we have studied the influence of tissue age on essential amino acid biosynthesis in pea (Pisum sativum) plastids. Chloroplasts from the younger (third and fourth) leaves of 12 day old plants, were 2-3 times more active in synthesizing lys and thr from [ 14 C]asp than those from older (first or second) leaves. We also examined two key pathway enzymes (aspartate kinase and homoserine dehydrogenase); with each enzyme,a activity in younger leaves was about 2 times that in plastids from older tissue. Both lys- and thr-sensitive forms of aspartate kinase are known in plants; in agreement with earlier work, we found that lys-sensitive activity was about 4 times higher in the younger tissues, while the thr-sensitive activity changed little during development (Davies and Miflin, 1977, Plant Sci. Lett. 9, 323). Recently the role of aspartate kinase and homoserine dehydrogenase in controlling asp-family amino acid synthesis has been questioned (Giovanelli et al, 1989, Plant Physiol. 90, 1584); we hope that measurements of amino acid levels in chloroplasts as well as further enzyme studies will help us to better understand the regulation of asp-family amino acid synthesis

  13. Elucidation of the biosynthesis of carnosic acid and its reconstitution in yeast.

    Science.gov (United States)

    Scheler, Ulschan; Brandt, Wolfgang; Porzel, Andrea; Rothe, Kathleen; Manzano, David; Božić, Dragana; Papaefthimiou, Dimitra; Balcke, Gerd Ulrich; Henning, Anja; Lohse, Swanhild; Marillonnet, Sylvestre; Kanellis, Angelos K; Ferrer, Albert; Tissier, Alain

    2016-10-05

    Rosemary extracts containing the phenolic diterpenes carnosic acid and its derivative carnosol are approved food additives used in an increasingly wide range of products to enhance shelf-life, thanks to their high anti-oxidant activity. We describe here the elucidation of the complete biosynthetic pathway of carnosic acid and its reconstitution in yeast cells. Cytochrome P450 oxygenases (CYP76AH22-24) from Rosmarinus officinalis and Salvia fruticosa already characterized as ferruginol synthases are also able to produce 11-hydroxyferruginol. Modelling-based mutagenesis of three amino acids in the related ferruginol synthase (CYP76AH1) from S. miltiorrhiza is sufficient to convert it to a 11-hydroxyferruginol synthase (HFS). The three sequential C20 oxidations for the conversion of 11-hydroxyferruginol to carnosic acid are catalysed by the related CYP76AK6-8. The availability of the genes for the biosynthesis of carnosic acid opens opportunities for the metabolic engineering of phenolic diterpenes, a class of compounds with potent anti-oxidant, anti-inflammatory and anti-tumour activities.

  14. Synthesis and Characterization of Dimmer-Acid-Based Nonisocyanate Polyurethane and Epoxy Resin Composite

    Directory of Open Access Journals (Sweden)

    Xin He

    2017-11-01

    Full Text Available In this study, dimmer-acid-based hybrid nonisocyanate polyurethanes (HNIPUs were synthesized by the one-step method without catalyst. Three polyamines and two epoxy resins were selected as raw materials for HNIPU, and cyclic carbonate was synthesized based on our previous work. All of the products were characterized by Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA and dynamic mechanical analysis (DMA. Then, HNIPU coatings were prepared and determined by swelling, water absorption, and water contact angle. The results showed that the HNIPU-4551 have the best mechanical and thermal properties because of its high crosslinking density. Among the different amines, it was confirmed that tetraethylenepentamine was the best amine curing agent for HNIPU coating. Meanwhile, the epoxy resin with a higher epoxy value would also form a higher crosslinking density. Those coatings showed an excellent impact strength, adhesion, flexibility, pencil hardness, hydrophilic, and appropriate crosslinking density.

  15. Stimulatory Effects of Acibenzolar-S-Methyl on Chlorogenic Acids Biosynthesis in Centella asiatica Cells

    Science.gov (United States)

    Ncube, Efficient N.; Steenkamp, Paul A.; Madala, Ntakadzeni E.; Dubery, Ian A.

    2016-01-01

    Centella asiatica is a perrenial herb that grows in tropical regions with numerous medicinal properties mostly attributed to the presence of pentacyclic triterpenoids. Interestingly, this plant also possess a significant amount of phenylpropanoid-derived chlorogenic acids (CGAs) that have recently been reported to confer neuroprotective properties. In a biotechnological attempt to increase the biosynthesis of CGA-derivatives in cultured Centella cells, acibenzolar-S-methyl was applied as a xenobiotic inducer in combination with quinic acid and shikimic acid as precursor molecules. Applying a semi-targeted metabolomics-based approach, time and concentration studies were undertaken to evaluate the effect of the manipulation on cellular metabolism leading to CGA production. Phytochemical extracts were prepared using methanol and analyzed using a UHPLC-qTOF-MS platform. Data was processed and analyzed using multivariate data models. A total of four CGA-derivatives, annotated as trans-5-feruloylquinic acid, 3,5 di-caffeoylquinic acid, 3,5-O-dicaffeoyl-4-O-malonylquinic acid (irbic acid) and 3-caffeoyl, 5-feruloylquinic acid, were found to be upregulated by the acibenzolar-S-methyl treatment. To the best of our knowledge, this is the first report on the induction of CGA derivatives in this species. Contrary to expectations, the effects of precursor molecules on the levels of the CGAs were insignificant. However, a total of 16 metabolites, including CGA derivatives, were up-regulated by precursor treatment. Therefore, this study shows potential to biotechnologically manipulate C. asiatica cells to increase the production of these health beneficial CGAs. PMID:27733862

  16. Stimulatory Effects of Acibenzolar-S-methyl on Chlorogenic Acids Biosynthesis in Centella asiatica Cells

    Directory of Open Access Journals (Sweden)

    Efficient N Ncube

    2016-09-01

    Full Text Available Centella asiatica is a perennial herb that grows in tropical regions with numerous medicinal properties, mostly attributed to the presence of pentacyclic triterpenoids. Interestingly, this plant also possess a significant amount of phenylpropanoid-derived chlorogenic acids (CGAs that have recently been reported to confer neuroprotective properties. In a biotechnological attempt to increase the biosynthesis of CGA-derivatives in cultured Centella cells, acibenzolar-S-methyl was applied as a xenobiotic inducer in combination with quinic acid and shikimic acid as precursor molecules. Applying a semi-targeted metabolomics-based approach, time and concentration studies were undertaken to evaluate the effect of the manipulation on cellular metabolism leading to CGA production. Phytochemical extracts were prepared using methanol and analysed using a UHPLC-qTOF-MS platform. Data was processed and analysed using multivariate data models. A total of four CGA-derivatives, annotated as trans-5-feruloylquinic acid, 3,5 di-caffeoylquinic acid, 3,5-O-dicaffeoyl-4-O-malonylquinic acid (irbic acid and 3-caffeoyl, 5-feruloylquinic acid, were found to be upregulated by the acibenzolar-S-methyl treatment. To the best of our knowledge, this is the first report on the induction of CGA derivatives in this species. Contrary to expectations, the precursor molecules had very little effects on the levels of the CGAs. However, a total of 16 metabolites, including CGA derivatives, were up-regulated by precursor treatment. Therefore, this study shows potential to biotechnologically manipulate C. asiatica cells to increase the production of these health beneficial CGAs.

  17. Uranium(VI) adsorption properties of a chelating resin containing polyamine-substituted methylphosphonic acid moiety

    International Nuclear Information System (INIS)

    Matsuda, Masaaki; Akiyoshi, Yoshirou

    1991-01-01

    Uranium(VI) adsorption and desorption properties of a chelating resin containing polyamine-substituted methylphosphonic acid moiety of 2.29 mmol/g-resin (APA) were examined. Uranium(VI) adsorption properties of several ion exchange resins and extractant agents which were known as excellent adsorbents for uranium(VI), were examined together for a comparison with those of APA. Uranium(VI) adsorption capacity of APA at the concentration of 100 mg·dm -3 -uranium(VI) in 100 g·dm -3 -H 2 SO 4 aq. soln., 190 g·dm -3 -H 3 PO 4 aq. soln. and uranium enriched sea water, was 0.2, 0.05 and 0.05 mmol·g -1 respectively. The adsorption capacity of APA for uranium(VI) in these solutions was larger than that of another adsorbents, except the adsorption of uranium(VI) in enriched sea water on ion exchange resin containing phosphoric acid moiety (adsorption capacity ; 0.2 mmol·g -1 ). Uranium(VI) adsorption rate on APA was high and the relation between treatment time (t : min) and uranium(VI) concentration (y : mg·dm -3 ) in 100 g·dm -3 H 2 SO 4 aq. soln. after treatment, was shown as following equation, y=20 0.048t+1.90 (0≤t≤30). The adsorbed uranium(VI) on APA was able to be eluted with a mixed aq. soln. of hydrogen peroxide and sodium hydroxide and also was able to be eluted with an aq. alkaline soln. dissolved reduction agents such as sodium sulfite and hydrazine. From these results, it was thought that uranium(VI) adsorbed on APA was eluted due to the reduction to uranium(VI) by these eluents. (author)

  18. Alternative oxidase impacts ganoderic acid biosynthesis by regulating intracellular ROS levels in Ganoderma lucidum.

    Science.gov (United States)

    Shi, Deng-Ke; Zhu, Jing; Sun, Ze-Hua; Zhang, Guang; Liu, Rui; Zhang, Tian-Jun; Wang, Sheng-Li; Ren, Ang; Zhao, Ming-Wen

    2017-10-01

    The alternative oxidase (AOX), which forms a branch of the mitochondrial respiratory electron transport pathway, functions to sustain electron flux and alleviate reactive oxygen species (ROS) production. In this article, a homologous AOX gene was identified in Ganoderma lucidum. The coding sequence of the AOX gene in G. lucidum contains 1038 nucleotides and encodes a protein of 39.48 kDa. RNA interference (RNAi) was used to study the function of AOX in G. lucidum, and two silenced strains (AOXi6 and AOXi21) were obtained, showing significant decreases of approximately 60 and 50 %, respectively, in alternative pathway respiratory efficiency compared to WT. The content of ganoderic acid (GA) in the mutant strains AOXi6 and AOXi21 showed significant increases of approximately 42 and 44 %, respectively, compared to WT. Elevated contents of intermediate metabolites in GA biosynthesis and elevated transcription levels of corresponding genes were also observed in the mutant strains AOXi6 and AOXi21. In addition, the intracellular ROS content in strains AOXi6 and AOXi21 was significantly increased, by approximately 1.75- and 1.93-fold, respectively, compared with WT. Furthermore, adding N-acetyl-l-cysteine (NAC), a ROS scavenger, significantly depressed the intracellular ROS content and GA accumulation in AOX-silenced strains. These results indicate that AOX affects GA biosynthesis by regulating intracellular ROS levels. Our research revealed the important role of AOX in the secondary metabolism of G. lucidum.

  19. Genetic control of ascorbic acid biosynthesis and recycling in horticultural crops

    Science.gov (United States)

    Mellidou, Ifigeneia; Kanellis, Angelos K.

    2017-07-01

    Ascorbic acid (AsA) is an essential compound present in almost all living organisms that has important functions in several aspects of plant growth and development, hormone signalling, as well as stress defense networks. In recent years, the genetic regulation of AsA metabolic pathways has received much attention due to its beneficial role in human diet. Despite the great variability within species, genotypes, tissues and developmental stages, AsA accumulation is considered to be controlled by the fine orchestration of net biosynthesis, recycling, degradation/oxidation, and/or intercellular and intracellular transport. To date, several structural genes from the AsA metabolic pathways and transcription factors are considered to significantly affect AsA in plant tissues, either at the level of activity, transcription or translation via feedback inhibition. Yet, all the emerging studies support the notion that the steps proceeding through GDP-L-galactose phosphorylase and to a lesser extent through GDP-D-mannose-3,5-epimerase are control points in governing AsA pool size in several species. In this mini review, we discuss the current consensus of the genetic regulation of AsA biosynthesis and recycling, with a focus on horticultural crops. The aspects of AsA degradation and transport are not discussed herein. Novel insights of how this multifaceted trait is regulated are critical to prioritize candidate genes for follow-up studies towards improving the nutritional value of fruits and vegetables.

  20. Effect of Eicosapentaenoic Acid and Docosahexaenoic Acid on Myogenesis and Mitochondrial Biosynthesis during Murine Skeletal Muscle Cell Differentiation.

    Science.gov (United States)

    Hsueh, Tun-Yun; Baum, Jamie I; Huang, Yan

    2018-01-01

    Polyunsaturated fatty acids are important nutrients for human health, especially omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have been found to play positive roles in the prevention of various diseases. However, previous studies have reported that excessive omega-3 fatty acids supplement during pregnancy caused side effects such as slower neural transmission times and postnatal growth restriction. In this study, we investigated the effect of EPA and DHA on mitochondrial function and gene expression in C2C12 myoblasts during skeletal muscle differentiation. C2C12 myoblasts were cultured to confluency and then treated with differentiation medium that contained fatty acids (50-µM EPA and DHA). After 72 h of myogenic differentiation, mRNA was collected, and gene expression was analyzed by real-time PCR. Microscopy was used to examine cell morphology following treatment with fatty acids. The effect of EPA and DHA on cellular oxygen consumption was measured using a Seahorse XF24 Analyzer. Cells treated with fatty acids had fewer myotubes formed ( P ≤ 0.05) compared with control cells. The expression of the genes related to myogenesis was significantly lower ( P ≤ 0.05) in cells treated with fatty acids, compared with control cells. Genes associated with adipogenesis had higher ( P ≤ 0.05) expression after treatment with fatty acids. Also, the mitochondrial biogenesis decreased with lower ( P ≤ 0.05) gene expression and lower ( P ≤ 0.05) mtDNA/nDNA ratio in cells treated with fatty acids compared with control cells. However, the expression of genes related to peroxisome biosynthesis was higher ( P ≤ 0.05) in cells treated with fatty acids. Moreover, fatty-acid treatment reduced ( P ≤ 0.05) oxygen consumption rate under oligomycin-inhibited (reflecting proton leak) and uncoupled conditions. Our data imply that fatty acids might reduce myogenesis and increase adipogenesis in myotube formation. Fatty acids

  1. Effect of Eicosapentaenoic Acid and Docosahexaenoic Acid on Myogenesis and Mitochondrial Biosynthesis during Murine Skeletal Muscle Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Tun-Yun Hsueh

    2018-03-01

    Full Text Available Polyunsaturated fatty acids are important nutrients for human health, especially omega-3 fatty acids such as eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA, which have been found to play positive roles in the prevention of various diseases. However, previous studies have reported that excessive omega-3 fatty acids supplement during pregnancy caused side effects such as slower neural transmission times and postnatal growth restriction. In this study, we investigated the effect of EPA and DHA on mitochondrial function and gene expression in C2C12 myoblasts during skeletal muscle differentiation. C2C12 myoblasts were cultured to confluency and then treated with differentiation medium that contained fatty acids (50-µM EPA and DHA. After 72 h of myogenic differentiation, mRNA was collected, and gene expression was analyzed by real-time PCR. Microscopy was used to examine cell morphology following treatment with fatty acids. The effect of EPA and DHA on cellular oxygen consumption was measured using a Seahorse XF24 Analyzer. Cells treated with fatty acids had fewer myotubes formed (P ≤ 0.05 compared with control cells. The expression of the genes related to myogenesis was significantly lower (P ≤ 0.05 in cells treated with fatty acids, compared with control cells. Genes associated with adipogenesis had higher (P ≤ 0.05 expression after treatment with fatty acids. Also, the mitochondrial biogenesis decreased with lower (P ≤ 0.05 gene expression and lower (P ≤ 0.05 mtDNA/nDNA ratio in cells treated with fatty acids compared with control cells. However, the expression of genes related to peroxisome biosynthesis was higher (P ≤ 0.05 in cells treated with fatty acids. Moreover, fatty-acid treatment reduced (P ≤ 0.05 oxygen consumption rate under oligomycin-inhibited (reflecting proton leak and uncoupled conditions. Our data imply that fatty acids might reduce myogenesis and increase adipogenesis in myotube formation. Fatty acids

  2. Non-destructive evaluation by terahertz spectroscopy for penetration of acid solutions into epoxy resin

    Directory of Open Access Journals (Sweden)

    M. Kusano

    2016-11-01

    Full Text Available Epoxy resins are used as high-performance thermosetting linings to protect substrates under corrosive environments. However, in a severe corrosive chemical solution, such protective layers may degrade with long time due to penetrations of solvent and solute molecules into resin network. In this regard, the terahertz time-domain spectroscopy (THz-TDS is a promising tool for non-destructive evaluation of the penetrant amounts due to high transparency of such plastic materials and high sensitivity to the molecular vibrations in terahertz spectral range. In this work, the complex refractive indexes n and κ of epoxy specimens were measured after immersion into sulfuric acid solutions and compared with penetrated mass fractions of water and acid ions. It was found that n and κ depended linearly with water and sulfuric acid mass fraction in specimens, and κ of sulfuric acid immersed specimens was lager at higher frequency. While the calculated Δκ agreed well with THz-TDS measurement by THz-TDS, the calculated Δn was higher than the measurement. The difference may be attributed to the water and sulfuric states in the specimen.

  3. Adsorption of beta-naphthalenesulfonic acid/sulfuric acid from their solution by weakly basic resin: equilibrium.

    Science.gov (United States)

    Li, Chang-Hai; Si, Peng-Fei

    2005-01-01

    Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of beta-naphthalenesulfonic acid (NSA) and sulfuric acid (H2SO4) from their solution at 25 degrees C onto weakly basic resin D301R. Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA. The data of single-solute adsorption were fitted to the Langmuir model and the Freundlich adsorption model. The ideal adsorbed solution theory (IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria. The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA, respectively, yields the favorable representation of the bisolute competitive adsorption behavior.

  4. Genetic analysis of pathway regulation for enhancing branched-chain amino acid biosynthesis in plants

    KAUST Repository

    Chen, Hao

    2010-08-01

    The branched-chain amino acids (BCAAs) valine, leucine and isoleucine are essential amino acids that play critical roles in animal growth and development. Animals cannot synthesize these amino acids and must obtain them from their diet. Plants are the ultimate source of these essential nutrients, and they synthesize BCAAs through a conserved pathway that is inhibited by its end products. This feedback inhibition has prevented scientists from engineering plants that accumulate high levels of BCAAs by simply over-expressing the respective biosynthetic genes. To identify components critical for this feedback regulation, we performed a genetic screen for Arabidopsis mutants that exhibit enhanced resistance to BCAAs. Multiple dominant allelic mutations in the VALINE-TOLERANT 1 (VAT1) gene were identified that conferred plant resistance to valine inhibition. Map-based cloning revealed that VAT1 encodes a regulatory subunit of acetohydroxy acid synthase (AHAS), the first committed enzyme in the BCAA biosynthesis pathway. The VAT1 gene is highly expressed in young, rapidly growing tissues. When reconstituted with the catalytic subunit in vitro, the vat1 mutant-containing AHAS holoenzyme exhibits increased resistance to valine. Importantly, transgenic plants expressing the mutated vat1 gene exhibit valine tolerance and accumulate higher levels of BCAAs. Our studies not only uncovered regulatory characteristics of plant AHAS, but also identified a method to enhance BCAA accumulation in crop plants that will significantly enhance the nutritional value of food and feed. © 2010 Blackwell Publishing Ltd.

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

    Science.gov (United States)

    Fernandes, João Daniel Santos; Martho, Kevin; Tofik, Veridiana; Vallim, Marcelo A.; Pascon, Renata C.

    2015-01-01

    Metabolic diversity is an important factor during microbial adaptation to different environments. Among metabolic processes, amino acid biosynthesis has been demonstrated to be relevant for survival for many microbial pathogens, whereas the association between pathogenesis and amino acid uptake and recycling are less well-established. Cryptococcus neoformans is an opportunistic fungal pathogen with many habitats. As a result, it faces frequent metabolic shifts and challenges during its life cycle. Here we studied the C. neoformans tryptophan biosynthetic pathway and found that the pathway is essential. RNAi indicated that interruptions in the biosynthetic pathway render strains inviable. However, auxotroph complementation can be partially achieved by tryptophan uptake when a non preferred nitrogen source and lower growth temperature are applied, suggesting that amino acid permeases may be the target of nitrogen catabolism repression (NCR). We used bioinformatics to search for amino acid permeases in the C. neoformans and found eight potential global permeases (AAP1 to AAP8). The transcriptional profile of them revealed that they are subjected to regulatory mechanisms which are known to respond to nutritional status in other fungi, such as (i) quality of nitrogen (Nitrogen Catabolism Repression, NCR) and carbon sources (Carbon Catabolism Repression, CCR), (ii) amino acid availability in the extracellular environment (SPS-sensing) and (iii) nutritional deprivation (Global Amino Acid Control, GAAC). This study shows that C. neoformans has fewer amino acid permeases than other model yeasts, and that these proteins may be subjected to complex regulatory mechanisms. Our data suggest that the C. neoformans tryptophan biosynthetic pathway is an excellent pharmacological target. Furthermore, inhibitors of this pathway cause Cryptococcus growth arrest in vitro. PMID:26162077

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

    Directory of Open Access Journals (Sweden)

    João Daniel Santos Fernandes

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

  7. Evaluation and improvement of gamma-ray stability of chelating resins containing oxy-acid groups of phosphorus

    International Nuclear Information System (INIS)

    Jyo, Akinori; Yamabe, Kazunori; Shuto, Taketomi

    1998-01-01

    Chelating resins containing oxy-acid groups of phosphorus, such as phosphonic and phosphoric acid groups have been studied from the point of view of solvent extraction processes for the separation of nuclear fuel elements as well as of fission product ones. The present work was planned to evaluate the effect of gamma-ray on properties of the resins and to obtain directional information for design of the resins having high stability to gamma-ray. It was clarified that gamma-ray stability of the resins is not high; tolerance limit is ca. 2.3x10 3 C/kg. The present work also clarified that polymers crosslinked with divinylbenzene have much higher gamma-ray stability than ones crosslinked with dimetacrylate esters of oligo (ethylene glycol)s. (J.P.N.)

  8. Application of 10% Ascorbic Acid Improves Resin Shear Bond Stregth in Bleached Dentin

    Directory of Open Access Journals (Sweden)

    Kamizar Kamizar

    2014-10-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Restoration of the teeth immediately after bleaching with H2O2 35% is contraindicated due to the remnants of free radical that will stay inside dentin for 2-3 weeks which will compromise the adhesiveness of composite resin. Objective: The aim of this study was to evaluate the influence of 10% ascorbic acid on shear bond strength of composite placed on bleached dentin. Methods:Twenty seven samples were divided equally into three groups. Group 1: dentin was etched with 35% phosphoric acid; Group 2: dentin was bleached with 35% H2O2 followed by etching with 35% phosphoric acid; Group 3: dentin was bleached with 35% H2O2, followed by application of 10% ascorbic acid and etched with 35% phosphoric acid. All samples were then stored at 370C for 24 hours. The Universal Testing Machine was used to measure shear bond strength and the results were analyzed with Kruskal Wallis and Mann Whitney test. Results: After nine independent experiments, 10% ascorbic acid application on bleached dentin resulted in highest increased in bond stregth (56.04±11.06MPa compared to Group 2 (29.09±7.63MPa and Group 1 (25.55±2.22MPa and the difference was statistically significant (p<0.05. Conclusion: Application of 10% ascorbic acid to the bleached dentin improved the shear bond strength of resin composite.

  9. Harnessing Yeast Peroxisomes for Biosynthesis of Fatty-Acid-Derived Biofuels and Chemicals with Relieved Side-Pathway Competition

    DEFF Research Database (Denmark)

    Zhou, Yongjin J.; Buijs, Nicolaas A; Zhu, Zhiwei

    2016-01-01

    to peroxisomes can increase the production of fatty-acid-derived fatty alcohols, alkanes and olefins up to 700%. In addition, we demonstrate that biosynthesis of these chemicals in the peroxisomes results in significantly decreased accumulation of byproducts formed by competing enzymes. We further demonstrate...

  10. TarO-specific inhibitors of wall teichoic acid biosynthesis restore β-lactam efficacy against methicillin-resistant staphylococci.

    Science.gov (United States)

    Lee, Sang Ho; Wang, Hao; Labroli, Marc; Koseoglu, Sandra; Zuck, Paul; Mayhood, Todd; Gill, Charles; Mann, Paul; Sher, Xinwei; Ha, Sookhee; Yang, Shu-Wei; Mandal, Mihir; Yang, Christine; Liang, Lianzhu; Tan, Zheng; Tawa, Paul; Hou, Yan; Kuvelkar, Reshma; DeVito, Kristine; Wen, Xiujuan; Xiao, Jing; Batchlett, Michelle; Balibar, Carl J; Liu, Jenny; Xiao, Jianying; Murgolo, Nicholas; Garlisi, Charles G; Sheth, Payal R; Flattery, Amy; Su, Jing; Tan, Christopher; Roemer, Terry

    2016-03-09

    The widespread emergence of methicillin-resistant Staphylococcus aureus (MRSA) has dramatically eroded the efficacy of current β-lactam antibiotics and created an urgent need for new treatment options. We report an S. aureus phenotypic screening strategy involving chemical suppression of the growth inhibitory consequences of depleting late-stage wall teichoic acid biosynthesis. This enabled us to identify early-stage pathway-specific inhibitors of wall teichoic acid biosynthesis predicted to be chemically synergistic with β-lactams. We demonstrated by genetic and biochemical means that each of the new chemical series discovered, herein named tarocin A and tarocin B, inhibited the first step in wall teichoic acid biosynthesis (TarO). Tarocins do not have intrinsic bioactivity but rather demonstrated potent bactericidal synergy in combination with broad-spectrum β-lactam antibiotics against diverse clinical isolates of methicillin-resistant staphylococci as well as robust efficacy in a murine infection model of MRSA. Tarocins and other inhibitors of wall teichoic acid biosynthesis may provide a rational strategy to develop Gram-positive bactericidal β-lactam combination agents active against methicillin-resistant staphylococci. Copyright © 2016, American Association for the Advancement of Science.

  11. Uranium adsorption from the sulphuric acid leach liquor containing more chlorides with cation-exchange resin SL-406

    International Nuclear Information System (INIS)

    Hu Jun; Wang Zhaoguo; Chi Renqing; Niu Xuejun

    1994-01-01

    The feasibility of uranium adsorption was studied from the sulphuric acid leach liquor of a uranium ore containing more chlorides with cation-exchange resin SL-406. The influence of some factors on uranium adsorption was investigated. It was shown that the resin possesses better selectivity, stability and higher capacity. It can be effectively used to recovery uranium from leach liquors of uranium ores containing more chlorides

  12. Effect of Hydrofluoric Acid Concentration on Resin Adhesion to a Feldspathic Ceramic.

    Science.gov (United States)

    Venturini, Andressa Borin; Prochnow, Catina; Rambo, Dagma; Gundel, Andre; Valandro, Luiz Felipe

    2015-08-01

    To evaluate the effect of different concentrations of hydrofluoric acid (HF) on the contact angle and the resin bond strength durability to feldspathic ceramic. To evaluate the contact angles of distilled water on etched feldspathic ceramic, 25 specimens (12×10×2.4 mm) of VitaBlocks Mark II were used, divided into 5 groups (n=5): one unconditioned control (UC) group with no ceramic surface treatment, and 4 other groups that were etched for 60 s with different concentrations of HF: 1% (HF1), 3% (HF3), 5% (HF5) and 10% (HF10). The bond testing utilized 40 ceramic blocks (12×10×4 mm) that were fabricated and subjected to the same surface treatments as previously mentioned (excluding the control). The etched surfaces were silanized and resin cement was applied. After 24 h, the blocks were sectioned to produce bar specimens that were divided into two groups, non-aged (immediate testing) and aged (storage for 230 days+12,000 thermocycles at 5°C and 55°C), and subjected to microtensile testing (μTBS). Micromorphogical analysis of the treated surfaces was also performed (atomic force and scanning electron microscopy). One-way ANOVA and Tukey's tests were applied for data analysis. UC had the highest contact angle (61.4°), whereas HF10 showed the lowest contact angle (17.5°). In non-aged conditions, different acids promoted statistically similar bond strengths (14.2 to 15.7 MPa) (p>0.05); in terms of bond durability, only the bond strength of the HF1 group presented a statistically significant decrease comparing before and after aging (14.5 to 10.2 MPa). When etched with 3%, 5%, or 10% hydrofluoric acid, the ceramic tested showed stable resin adhesion after long-term aging.

  13. Reconstruction of diaminopimelic acid biosynthesis allows characterisation of Mycobacterium tuberculosis N-succinyl-L,L-diaminopimelic acid desuccinylase.

    Science.gov (United States)

    Usha, Veeraraghavan; Lloyd, Adrian J; Roper, David I; Dowson, Christopher G; Kozlov, Guennadi; Gehring, Kalle; Chauhan, Smita; Imam, Hasan T; Blindauer, Claudia A; Besra, Gurdyal S

    2016-03-15

    With the increased incidence of tuberculosis (TB) caused by Mycobacterium tuberculosis there is an urgent need for new and better anti-tubercular drugs. N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) is a key enzyme in the succinylase pathway for the biosynthesis of meso-diaminopimelic acid (meso-DAP) and L-lysine. DapE is a zinc containing metallohydrolase which hydrolyses N-succinyl L,L diaminopimelic acid (L,L-NSDAP) to L,L-diaminopimelic acid (L,L-DAP) and succinate. M. tuberculosis DapE (MtDapE) was cloned, over-expressed and purified as an N-terminal hexahistidine ((His)6) tagged fusion containing one zinc ion per DapE monomer. We redesigned the DAP synthetic pathway to generate L,L-NSDAP and other L,L-NSDAP derivatives and have characterised MtDapE with these substrates. In contrast to its other Gram negative homologues, the MtDapE was insensitive to inhibition by L-captopril which we show is consistent with novel mycobacterial alterations in the binding site of this drug.

  14. Adsorption behavior of benzenesulfonic acid by novel weakly basic anion exchange resins.

    Science.gov (United States)

    Sun, Yue; Zuo, Peng; Luo, Junfen; Singh, Rajendra Prasad

    2017-04-01

    Two novel weakly basic anion exchange resins (SZ-1 and SZ-2) were prepared via the reaction of macroporous chloromethylated polystyrene-divinylbenzene (Cl-PS-DVB) beads with dicyclohexylamine and piperidine, respectively. The physicochemical structures of the resulting resins were characterized using Fourier Transform Infrared Spectroscopy and pore size distribution analysis. The adsorption behavior of SZ-1 and SZ-2 for benzenesulfonic acid (BA) was evaluated, and the common commercial weakly basic anion exchanger D301 was also employed for comparison purpose. Adsorption isotherms and influence of solution pH, temperature and coexisting competitive inorganic salts (Na 2 SO 4 and NaCl) on adsorption behavior were investigated and the optimum desorption agent was obtained. Adsorption isotherms of BA were found to be well represented by the Langmuir model. Thermodynamic parameters involving ΔH, ΔG and ΔS were also calculated and the results indicate that adsorption is an exothermic and spontaneous process. Enhanced selectivity of BA sorption over sulfate on the two novel resins was observed by comparison with the commercial anion exchanger D301. The fact that the tested resins loaded with BA can be efficiently regenerated by NaCl solution indicates the reversible sorption process. From a mechanistic viewpoint, this observation clearly suggests that electrostatic interaction is the predominant adsorption mechanism. Furthermore, results of column tests show that SZ-1 possesses a better adsorption property than D301, which reinforces the feasibility of SZ-1 for potential industrial application. Copyright © 2016. Published by Elsevier B.V.

  15. HTGR fuel development: loading of uranium on carboxylic acid cation-exchange resins using solvent extraction of nitrate

    International Nuclear Information System (INIS)

    Haas, P.A.

    1975-09-01

    The reference fuel kernel for recycle of 233 U to HTGR's (High-Temperature Gas-Cooled Reactors) is prepared by loading carboxylic acid cation-exchange resins with uranium and carbonizing at controlled conditions. The purified 233 UO 2 (NO 3 ) 2 solution from a fuel reprocessing plant contains excess HNO 3 (NO 3 - /U ratio of approximately 2.2). The reference flowsheet for a 233 U recycle fuel facility at Oak Ridge uses solvent extraction of nitrate by a 0.3 M secondary amine in a hydrocarbon diluent to prepare acid-deficient uranyl nitrate. This nitrate extraction, along with resin loading and amine regeneration steps, was demonstrated in 14 runs. No significant operating difficulties were encountered. The process is controlled via in-line pH measurements for the acid-deficient uranyl nitrate solutions. Information was developed on pH values for uranyl nitrate solution vs NO 3 - /U mole ratios, resin loading kinetics, resin drying requirements, and other resin loading process parameters. Calculations made to estimate the capacities of equipment that is geometrically safe with respect to control of nuclear criticality indicate 100 kg/day or more of uranium for single nitrate extraction lines with one continuous resin loading contactor or four batch loading contactors. (auth)

  16. Fracture Toughness Evaluation of Hybrid and Nano-hybrid Resin Composites after Ageing under Acidic Environment

    Directory of Open Access Journals (Sweden)

    Ferooz M

    2015-03-01

    Full Text Available Statement of Problem: Tooth-coloured restorative materials are brittle with the major shortcomings of sensitivity to flaws and defects. Although various mechanical properties of resin composites have been studied, no fracture toughness test data for nano-hybrid composites under acidic condition for a long period of time has been published. Objectives: To compare the fracture toughness (KIc of two types of resin composites under tensile loading and to assess the effect of distilled water and lactic acid on the resistance of the restoratives to fracture after three months of immersion. Materials and Methods: Four resin composites were used: three nanohybrids [EsteliteSigma Quick (Kuraray, Luna (SDI, Paradigm (3M/ESPE] and one hybrid, Rok (SDI. The specimens were prepared using a custom-made polytetrafluorethylene split mould, stored in distilled water (pH 6.8 or 0.01mol/L lactic acid (pH 4 and conditioned at 37°C for 24 hours, 1 or 3 months. They were loaded under tensile stress using a universal testing machine; the maximum load (N to the specimen failure was recorded and the fracture toughness (KIc was calculated. Data were analysed by ANOVA and Tukey’s test using SPSS, version 18. Results: The results of two-way ANOVA did not show a significant combined effect of material, time, and storage medium on fracture toughness (p= 0.056. However, there was a strong interaction between materials and time (p=0.001 when the storage medium were ignored. After 24 h of immersion in distilled water, Paradigm revealed the highest KIc values followed by Rok, Luna and Estelite. Immersion in either distilled water or lactic acid significantly decreased the fracture toughness of almost all materials as time interval increased. Conclusions: Paradigm showed the highest fracture toughness followed by Rok, Luna and Estelite respectively. As time increased, KIc significantly decreased for almost all resin composites except for Luna which showed a slight decrease

  17. Streptomyces clavuligerus shows a strong association between TCA cycle intermediate accumulation and clavulanic acid biosynthesis.

    Science.gov (United States)

    Ramirez-Malule, Howard; Junne, Stefan; Nicolás Cruz-Bournazou, Mariano; Neubauer, Peter; Ríos-Estepa, Rigoberto

    2018-05-01

    Clavulanic acid (CA) is produced by Streptomyces clavuligerus (S. clavuligerus) as a secondary metabolite. Knowledge about the carbon flux distribution along the various routes that supply CA precursors would certainly provide insights about metabolic performance. In order to evaluate metabolic patterns and the possible accumulation of tricarboxylic acid (TCA) cycle intermediates during CA biosynthesis, batch and subsequent continuous cultures with steadily declining feed rates were performed with glycerol as the main substrate. The data were used to in silico explore the metabolic capabilities and the accumulation of metabolic intermediates in S. clavuligerus. While clavulanic acid accumulated at glycerol excess, it steadily decreased at declining dilution rates; CA synthesis stopped when glycerol became the limiting substrate. A strong association of succinate, oxaloacetate, malate, and acetate accumulation with CA production in S. clavuligerus was observed, and flux balance analysis (FBA) was used to describe the carbon flux distribution in the network. This combined experimental and numerical approach also identified bottlenecks during the synthesis of CA in a batch and subsequent continuous cultivation and demonstrated the importance of this type of methodologies for a more advanced understanding of metabolism; this potentially derives valuable insights for future successful metabolic engineering studies in S. clavuligerus.

  18. Indole-3-Acetic Acid Biosynthesis Pathways in the Plant-Beneficial Bacterium Arthrobacter pascens ZZ21.

    Science.gov (United States)

    Li, Mengsha; Guo, Rui; Yu, Fei; Chen, Xu; Zhao, Haiyan; Li, Huixin; Wu, Jun

    2018-02-01

    Arthrobacter pascens ZZ21 is a plant-beneficial, fluoranthene-degrading bacterial strain found in the rhizosphere. The production of the phytohormone indole-3-aectic acid (IAA) by ZZ21 is thought to contribute to its ability to promote plant growth and remediate fluoranthene-contaminated soil. Using genome-wide analysis combined with metabolomic and high-performance liquid chromatography-mass spectrometry (HPLC-MS) analyses, we characterized the potential IAA biosynthesis pathways in A. pascens ZZ21. IAA production increased 4.5-fold in the presence of 200 mg·L -1 tryptophan in the culture medium. The transcript levels of prr and aldH , genes which were predicted to encode aldehyde dehydrogenases, were significantly upregulated in response to exogenous tryptophan. Additionally, metabolomic analysis identified the intermediates indole-3-acetamide (IAM), indole-3-pyruvic acid (IPyA), and the enzymatic reduction product of the latter, indole-3-lactic acid (ILA), among the metabolites of ZZ21, and subsequently also IAM, ILA, and indole-3-ethanol (TOL), which is the enzymatic reduction product of indole-3-acetaldehyde, by HPLC-MS. These results suggest that the tryptophan-dependent IAM and IPyA pathways function in ZZ21.

  19. Interferon-α2b against microbes through promoting biosynthesis of unsaturated fatty acids.

    Science.gov (United States)

    Zhao, Xianliang; Wu, Changwen; Peng, Xuanxian; Li, Hui

    2014-09-05

    Interferon (IFN) family is a large group of cytokines involved in innate immune response against various microorganisms. However, whether IFN functions in antimicrobial property by metabolic pathways is largely unknown. In the present study, GC-MS-based metabolome is investigated in humoral fluid of zebrafish (Danio rerio) which are exposed to three doses of IFN-α2b, designed as IFN-L, IFN-M, and IFN-H. Out of 67 compounds identified, 19, 28, and 29 differential abundances of metabolites are identified in the three groups compared with control, respectively. A total of 41 differential metabolites constructed IFN-dependent metabolome, in which 13 overlap among the three doses of IFN-α2b groups. These overlapped metabolites show that decreased alanine asparate and glutamate metabolic pathway, arginine and proline metabolic pathway, and increased purine metabolism form a characteristic feature in response to IFN-α2b. Further dose-related metabolites indicate that biosynthesis of unsaturated fatty acids is enriched only in IFN-M and IFN-H, which is related to high protection against bacterial infection. Exogenous fatty acids, especially unsaturated linoleic acid, may elevate the survival ability of zebrafish infected with extracellular pathogenic V. alginolyticus and intracellular pathogenic Edwardsiella tarda. These results disclose an unknown mechanism by which IFN-α2b protects host from microbial infections. Our findings highlight the ways to understand action of IFN in content of metabolic regulation.

  20. Linoleic acid biosynthesis and characterization of the. Delta. sup 12 desaturase in insects

    Energy Technology Data Exchange (ETDEWEB)

    Cripps, C.

    1988-01-01

    De novo biosynthesis of linoleic acid was demonstrated in vivo in 8 of 32 insect species examined, including both holometabolous and hemimetabolous species. The incorporation of (1-{sup 14}C) acetate into linoleic acid was demonstrated by radio-gas-liquid chromatography (radio-GLC), and in selected species by radio-high-performance liquid chromatography, silver nitrate thin-layer chromatography, radio-GLC and GLC linked to mass spectrometry of ozonolysis products. Analysis of the ozonolysis products clearly demonstrated that the entire molecule was labeled and that synthesis of linoleate was de novo from acetate. The in vivo incorporation of (1-{sup 14}C)acetate into lipid was monitored during the final three stadia of both male and female house crickets, Acheta domesticus. Characterization of the {Delta}{sup 12}-desaturase showed that, in the house cricket, this enzyme is microsomal and requires a reduced pyridine dinucleotide as a cofactor, with NADPH the preferred electron donor. The optimal substrate concentration for desaturation is about 40 uM. Addition of the microsomal supernatant, MgCl{sub 2} or ATP did not enhance activity. The form of the substrate for the desaturase, oleic acid, was determined and appears to be a CoA derivative, as is true for most animal desaturases, rather than a complex lipid, as it is in plants.

  1. Chlorogenic Acids Biosynthesis in Centella asiatica Cells Is not Stimulated by Salicylic Acid Manipulation.

    Science.gov (United States)

    Ncube, E N; Steenkamp, P A; Madala, N E; Dubery, I A

    2016-07-01

    Exogenous application of synthetic and natural elicitors of plant defence has been shown to result in mass production of secondary metabolites with nutraceuticals properties in cultured cells. In particular, salicylic acid (SA) treatment has been reported to induce the production of phenylpropanoids, including cinnamic acid derivatives bound to quinic acid (chlorogenic acids). Centella asiatica is an important medicinal plant with several therapeutic properties owing to its wide spectrum of secondary metabolites. We investigated the effect of SA on C. asiatica cells by monitoring perturbation of chlorogenic acids in particular. Different concentrations of SA were used to treat C. asiatica cells, and extracts from both treated and untreated cells were analysed using an optimised UHPLC-QTOF-MS/MS method. Semi-targeted multivariate data analyses with the aid of principal component analysis (PCA) and orthogonal projection to latent structures-discriminant analysis (OPLS-DA) revealed a concentration-dependent metabolic response. Surprisingly, a range of chlorogenic acid derivatives were found to be downregulated as a consequence of SA treatment. Moreover, irbic acid (3,5-O-dicaffeoyl-4-O-malonilquinic acid) was found to be a dominant CGA in C. asiatica cells, although the SA treatment also had a negative effect on its concentration. Overall SA treatment was found to be an ineffective elicitor of CGA production in cultured C. asiatica cells.

  2. Biosynthesis of gallic and ellagic acids with 14C-labeled compounds in Acer and Rhus leaves

    International Nuclear Information System (INIS)

    Ishikura, Nariyuki; Hayashida, Shunzo; Tazaki, Kiyoshi

    1984-01-01

    The biosynthetic pathway for gallic and ellagic acids in young, mature and autumn leaves of Acer buergerianum and Rhus succedanea was examined by tracer experiments, and also by isotope competition, with D-shikimic acid- 14 C, L-phenylalanine-U- 14 C, L-phenyllactic acid-U- 14 C, gallic acid-G- 14 C and their unlabeled compounds. In young leaves of both plants, the incorporation rate of labeled shikimic acid into gallic acid was significantly higher than that of labeled phenylalanine, whereas in the mature and autumn leaves the latter was a good precursor rather than the former for the gallic acid biosynthesis. Therefore, two pathways for gallic acid formation, through β-oxidation of phenylpropanoid and through dehydrogenation of shikimic acid, could be operating in Acer and Rhus leaves, and the preferential pathway is altered by leaf age. In both plants, the incorporation rate of labeled phenyllactic acid during a 24 hr metabolic period was almost the same as that of labeled phenylalanine. The incorporation of D-shikimic acid-G- 14 C, L-phenylalanine-U- 14 C and L-phenyllactic acid-U- 14 C into ellagic acid was very similar to the case of the radioactive gallic acid formation. Furthermore, regardless of the presence of unlabeled shikimic acid and/or phenylalanine, incorporation of the radioactivity of labeled gallic acid into ellagic acid occurred at a very high rate, suggesting the reciprocal radical reaction of gallic acid for the ellagic acid formation. The incorporation of labeled compounds into ellagitannins was also examined and their biosynthesis discussed further. (author)

  3. Metabolomics analysis and biosynthesis of rosmarinic acid in Agastache rugosa Kuntze treated with methyl jasmonate.

    Directory of Open Access Journals (Sweden)

    Yeon Bok Kim

    Full Text Available This study investigated the effect of methyl jasmonate (MeJA on metabolic profiles and rosmarinic acid (RA biosynthesis in cell cultures of Agastache rugosa Kuntze. Transcript levels of phenylpropanoid biosynthetic genes, i.e., ArPAL, Ar4CL, and ArC4H, maximally increased 4.5-fold, 3.4-fold, and 3.5-fold, respectively, compared with the untreated controls, and the culture contained relatively high amounts of RA after exposure of cells to 50 µM MeJA. RA levels were 2.1-, 4.7-, and 3.9-fold higher after exposure to 10, 50, and 100 µM MeJA, respectively, than those in untreated controls. In addition, the transcript levels of genes attained maximum levels at different time points after the initial exposure. The transcript levels of ArC4H and Ar4CL were transiently induced by MeJA, and reached a maximum of up to 8-fold at 3 hr and 6 hr, respectively. The relationships between primary metabolites and phenolic acids in cell cultures of A. rugosa treated with MeJA were analyzed by gas chromatography coupled with time-of-flight mass spectrometry. In total, 45 metabolites, including 41 primary metabolites and 4 phenolic acids, were identified from A. rugosa. Metabolite profiles were subjected to partial least square-discriminate analysis to evaluate the effects of MeJA. The results indicate that both phenolic acids and precursors for the phenylpropanoid biosynthetic pathway, such as aromatic amino acids and shikimate, were induced as a response to MeJA treatment. Therefore, MeJA appears to have an important impact on RA accumulation, and the increased RA accumulation in the treated cells might be due to activation of the phenylpropanoid genes ArPAL, ArC4H, and Ar4CL.

  4. Fatty acid biosynthesis is involved in the production of hepatitis B virus particles

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, Hitomi [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyoku, Kyoto 606-8501 (Japan); Nio, Yasunori, E-mail: yasunori.nio@takeda.com [Takeda Pharmaceutical Company Limited, Pharmaceutical Research Division, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555 (Japan); Akahori, Yuichi [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyoku, Kyoto 606-8501 (Japan); Kim, Sulyi [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Watashi, Koichi [Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640 (Japan); Department of Applied Biological Science, Tokyo University of Sciences, Noda 278-8510 (Japan); CREST, Japan Science and Technology Agency (JST), Saitama 332-0012 (Japan); Wakita, Takaji [Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640 (Japan); Hijikata, Makoto, E-mail: mhijikat@virus.kyoto-u.ac.jp [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyoku, Kyoto 606-8501 (Japan)

    2016-06-17

    Hepatitis B virus (HBV) proliferates in hepatocytes after infection, but the host factors that contribute to the HBV lifecycle are poorly understood at the molecular level. We investigated whether fatty acid biosynthesis (FABS), which was recently reported to contribute to the genomic replication of hepatitis C virus, plays a role in HBV proliferation. We examined the effects of inhibitors of the enzymes in the FABS pathway on the HBV lifecycle by using recombinant HBV-producing cultured cells and found that the extracellular HBV DNA level, reflecting HBV particle production, was decreased by treatment with inhibitors suppressed the synthesis of long-chain saturated fatty acids with little cytotoxicity. The reduced HBV DNA level was reversed when palmitic acid, which is the product of fatty acid synthase (FAS) during FABS, was used simultaneously with the inhibitor. We also observed that the amount of intracellular HBV DNA in the cells was increased by FAS inhibitor treatment, suggesting that FABS is associated with HBV particle production but not its genome replication. This suggests that FABS might be a potent target for anti-HBV drug with a mode of action different from current HBV therapy. -- Highlights: •Inhibitors of ACC1 and FAS but not SCD1 decreased production of extracellular HBV DNA. •Products of FABS, long chain fatty acids, increased production of extracellular HBV DNA. •FAS inhibitor increased intracellular levels of HBV DNA and HBcAg. •FABS was suggested to contribute to HBV particle production without significant relation with secretory pathway of the cells.

  5. Impact of Chemical Analogs of 4-Hydroxybenzoic Acid on Coenzyme Q Biosynthesis: From Inhibition to Bypass of Coenzyme Q Deficiency

    Directory of Open Access Journals (Sweden)

    Fabien Pierrel

    2017-06-01

    Full Text Available Coenzyme Q is a lipid that participates to important physiological functions. Coenzyme Q is synthesized in multiple steps from the precursor 4-hydroxybenzoic acid. Mutations in enzymes that participate to coenzyme Q biosynthesis result in primary coenzyme Q deficiency, a type of mitochondrial disease. Coenzyme Q10 supplementation of patients is the classical treatment but it shows limited efficacy in some cases. The molecular understanding of the coenzyme Q biosynthetic pathway allowed the design of experiments to bypass deficient biosynthetic steps with analogs of 4-hydroxybenzoic acid. These molecules provide the defective chemical group and can reactivate endogenous coenzyme Q biosynthesis as demonstrated recently in yeast, mammalian cell cultures, and mouse models of primary coenzyme Q deficiency. This mini review presents how the chemical properties of various analogs of 4-hydroxybenzoic acid dictate the effect of the molecules on CoQ biosynthesis and how the reactivation of endogenous coenzyme Q biosynthesis may achieve better results than exogenous CoQ10 supplementation.

  6. Poly(3-hydroxybutyrate) fuels the tricarboxylic acid cycle and de novo lipid biosynthesis during Bacillus anthracis sporulation.

    Science.gov (United States)

    Sadykov, Marat R; Ahn, Jong-Sam; Widhelm, Todd J; Eckrich, Valerie M; Endres, Jennifer L; Driks, Adam; Rutkowski, Gregory E; Wingerd, Kevin L; Bayles, Kenneth W

    2017-06-01

    Numerous bacteria accumulate poly(3-hydroxybutyrate) (PHB) as an intracellular reservoir of carbon and energy in response to imbalanced nutritional conditions. In Bacillus spp., where PHB biosynthesis precedes the formation of the dormant cell type called the spore (sporulation), the direct link between PHB accumulation and efficiency of sporulation was observed in multiple studies. Although the idea of PHB as an intracellular carbon and energy source fueling sporulation was proposed several decades ago, the mechanisms underlying PHB contribution to sporulation have not been defined. Here, we demonstrate that PHB deficiency impairs Bacillus anthracis sporulation through diminishing the energy status of the cells and by reducing carbon flux into the tricarboxylic acid (TCA) cycle and de novo lipid biosynthesis. Consequently, this metabolic imbalance decreased biosynthesis of the critical components required for spore integrity and resistance, such as dipicolinic acid (DPA) and the spore's inner membrane. Supplementation of the PHB deficient mutant with exogenous fatty acids overcame these sporulation defects, highlighting the importance of the TCA cycle and lipid biosynthesis during sporulation. Combined, the results of this work reveal the molecular mechanisms of PHB contribution to B. anthracis sporulation and provide valuable insight into the metabolic requirements for this developmental process in Bacillus species. © 2017 John Wiley & Sons Ltd.

  7. Chlorogenic acids biosynthesis in Centella asiatica cells is not stimulated by salicylic acid manipulation

    CSIR Research Space (South Africa)

    Ncube, EN

    2016-07-01

    Full Text Available Exogenous application of synthetic and natural elicitors of plant defence has been shown to result in mass production of secondary metabolites with nutraceuticals properties in cultured cells. In particular, salicylic acid (SA) treatment has been...

  8. Molecular annotation of ketol-acid reductoisomerases from Streptomyces reveals a novel amino acid biosynthesis interlock mediated by enzyme promiscuity

    Science.gov (United States)

    Verdel-Aranda, Karina; López-Cortina, Susana T; Hodgson, David A; Barona-Gómez, Francisco

    2015-01-01

    The 6-phosphogluconate dehydrogenase superfamily oxidize and reduce a wide range of substrates, making their functional annotation challenging. Ketol-acid reductoisomerase (KARI), encoded by the ilvC gene in branched-chain amino acids biosynthesis, is a promiscuous reductase enzyme within this superfamily. Here, we obtain steady-state enzyme kinetic parameters for 10 IlvC homologues from the genera Streptomyces and Corynebacterium, upon eight selected chemically diverse substrates, including some not normally recognized by enzymes of this superfamily. This biochemical data suggested a Streptomyces biosynthetic interlock between proline and the branched-chain amino acids, mediated by enzyme substrate promiscuity, which was confirmed via mutagenesis and complementation analyses of the proC, ilvC1 and ilvC2 genes in Streptomyces coelicolor. Moreover, both ilvC orthologues and paralogues were analysed, such that the relationship between gene duplication and functional diversification could be explored. The KARI paralogues present in S. coelicolor and Streptomyces lividans, despite their conserved high sequence identity (97%), were shown to be more promiscuous, suggesting a recent functional diversification. In contrast, the KARI paralogue from Streptomyces viridifaciens showed selectivity towards the synthesis of valine precursors, explaining its recruitment within the biosynthetic gene cluster of valanimycin. These results allowed us to assess substrate promiscuity indices as a tool to annotate new molecular functions with metabolic implications. PMID:25296650

  9. Enhanced Biosynthesis of Hyaluronic Acid Using Engineered Corynebacterium glutamicum Via Metabolic Pathway Regulation.

    Science.gov (United States)

    Cheng, Fangyu; Luozhong, Sijin; Guo, Zhigang; Yu, Huimin; Stephanopoulos, Gregory

    2017-10-01

    Hyaluronic acid (HA) is a polysaccharide used in many industries such as medicine, surgery, cosmetics, and food. To avoid potential pathogenicity caused by its native producer, Streptococcus, efforts have been made to create a recombinant host for HA production. In this work, a GRAS (generally recognized as safe) strain, Corynebacterium glutamicum, is engineered for enhanced biosynthesis of HA via metabolic pathway regulation. Five enzymes (HasA-HasE) involved in the HA biosynthetic pathway are highlighted, and eight diverse operon combinations, including HasA, HasAB, HasAC, HasAD, HasAE, HasABC, HasABD, and HasABE, are compared. HasAB and HasABC are found to be optimal for HA biosynthesis in C. glutamicum. To meet the energy demand for HA synthesis, the metabolic pathway that produces lactate is blocked by knocking out the lactate dehydrogenase (LDH) gene using single crossover homologous recombination. Engineered C. glutamicum/Δldh-AB is superior and had a significantly higher HA titer than C. glutamicum/Δldh-ABC. Batch and fed-batch cultures of C. glutamicum/Δldh-AB are performed in a 5-L fermenter. Using glucose feeding, the maximum HA titer reached 21.6 g L -1 , more than threefolds of that of the wild-type Streptococcus. This work provides an efficient, safe, and novel recombinant HA producer, C. glutamicum/Δldh-AB, via metabolic pathway regulation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. BIOLOGICAL ROLE OF ALDO-KETO REDUCTASES IN RETINOIC ACID BIOSYNTHESIS AND SIGNALING

    Directory of Open Access Journals (Sweden)

    F. Xavier eRuiz

    2012-04-01

    Full Text Available Several aldo-keto reductase (AKR enzymes from subfamilies 1B and 1C show retinaldehyde reductase activity, having low Km and kcat values. Only AKR1B10 and 1B12, with all-trans-retinaldehyde, and AKR1C3, with 9-cis-retinaldehyde, display high catalytic efficiency. Major structural determinants for retinaldehyde isomer specificity are located in the external loops (A and C for AKR1B10, and B for AKR1C3, as assessed by site-directed mutagenesis and molecular dynamics. Cellular models have shown that AKR1B and 1C enzymes are well suited to work in vivo as retinaldehyde reductases and to regulate retinoic acid (RA biosynthesis at hormone pre-receptor level. An additional physiological role for the retinaldehyde reductase activity of these enzymes, consistent with their tissue localization, is their participation in β-carotene absorption. Retinaldehyde metabolism may be subjected to subcellular compartmentalization, based on enzyme localization. While retinaldehyde oxidation to RA takes place in the cytosol, reduction to retinol could take place in the cytosol by AKRs or in the membranes of endoplasmic reticulum by microsomal retinaldehyde reductases. Upregulation of some AKR1 enzymes in different cancer types may be linked to their induction by oxidative stress and to their participation in different signaling pathways related to cell proliferation. AKR1B10 and AKR1C3, through their retinaldehyde reductase activity, trigger a decrease in the RA biosynthesis flow, resulting in RA deprivation and consequently lower differentiation, with an increased cancer risk in target tissues. Rational design of selective AKR inhibitors could lead to development of novel drugs for cancer treatment as well as reduction of chemotherapeutic drug resistance.

  11. Coordinated Regulation of Species-Specific Hydroxycinnamic Acid Degradation and Siderophore Biosynthesis Pathways in Agrobacterium fabrum

    Science.gov (United States)

    Baude, Jessica; Vial, Ludovic; Villard, Camille; Campillo, Tony; Lavire, Céline; Nesme, Xavier

    2016-01-01

    ABSTRACT The rhizosphere-inhabiting species Agrobacterium fabrum (genomospecies G8 of the Agrobacterium tumefaciens species complex) is known to degrade hydroxycinnamic acids (HCAs), especially ferulic acid and p-coumaric acid, via the novel A. fabrum HCA degradation pathway. Gene expression profiles of A. fabrum strain C58 were investigated in the presence of HCAs, using a C58 whole-genome oligoarray. Both ferulic acid and p-coumaric acid caused variations in the expression of more than 10% of the C58 genes. Genes of the A. fabrum HCA degradation pathway, together with the genes involved in iron acquisition, were among the most highly induced in the presence of HCAs. Two operons coding for the biosynthesis of a particular siderophore, as well as genes of the A. fabrum HCA degradation pathway, have been described as being specific to the species. We demonstrate here their coordinated expression, emphasizing the interdependence between the iron concentration in the growth medium and the rate at which ferulic acid is degraded by cells. The coordinated expression of these functions may be advantageous in HCA-rich but iron-starved environments in which microorganisms have to compete for both iron and carbon sources, such as in plant roots. The present results confirm that there is cooperation between the A. fabrum-specific genes, defining a particular ecological niche. IMPORTANCE We previously identified seven genomic regions in Agrobacterium fabrum that were specifically present in all of the members of this species only. Here we demonstrated that two of these regions, encoding the hydroxycinnamic acid degradation pathway and the iron acquisition pathway, were regulated in a coordinated manner. The coexpression of these functions may be advantageous in hydroxycinnamic acid-rich but iron-starved environments in which microorganisms have to compete for both iron and carbon sources, such as in plant roots. These data support the view that bacterial genomic species

  12. Association between polyunsaturated fatty acid-derived oxylipid biosynthesis and leukocyte inflammatory marker expression in periparturient dairy cows.

    Science.gov (United States)

    Raphael, W; Halbert, L; Contreras, G A; Sordillo, L M

    2014-01-01

    Peripheral blood mononuclear leukocytes from periparturient cows can have exacerbated inflammatory responses that contribute to disease incidence and severity. Oxylipids derived from the oxygenation of polyunsaturated fatty acids (PUFA) can regulate the magnitude and duration of inflammation. Although PUFA substrate for oxylipid biosynthesis in leukocytes is known to change across the periparturient period, the plasma oxylipid profile and how this profile relates to leukocyte inflammatory phenotype is not clear. The objective of this study was to determine if a relationship exists between the profile of pro- and antiinflammatory plasma oxylipids and the inflammatory phenotype of peripheral blood leukocytes during the periparturient period. Seven multiparous Holsteins were sampled from the prepartum period through peak lactation. Plasma oxylipids were measured by liquid chromatography-mass spectrometry, peripheral leukocyte mRNA expression was measured by quantitative PCR, and PUFA content of peripheral blood mononuclear cells was measured by gas chromatography-mass spectrometry. Concentrations of several hydroxyl products of linoleic and arachidonic acid changed over time. Linoleic acid and arachidonic acid concentrations in leukocytes increased during early lactation, suggesting that substrate availability for hydroxyoctadecadienoic and hydroxyeicosatetraenoic acid biosynthesis may influence the oxylipid profile. Leukocyte mRNA expressions of IL-12B, IL-1B, inducible nitric oxide synthase 2, and cyclooxygenase 2 were correlated with several plasma oxylipids. These are the first observations linking leukocyte inflammatory gene responses to shifts in oxylipid biosynthesis in periparturient dairy cows. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Affinity purification of the voltage-sensitive sodium channel from electroplax with resins selective for sialic acid

    Energy Technology Data Exchange (ETDEWEB)

    James, W.M.; Emerick, M.C.; Agnew, W.S. (Yale Univ. School of medicine, New Haven, CT (USA))

    1989-07-11

    The voltage-sensitive sodium channel present in the eel (Electrophorus electricus) has an unusually high content of sialic acid, including {alpha}-(2{yields}8)-linked polysialic acid, not found in other electroplax membrane glycopeptides. Lectins from Limax flavus (LFA) and wheat germ (WGA) proved the most effective of 11 lectin resins tried. The most selective resin was prepared from IgM antibodies against Neisseria meningitidis {alpha}-(2{yields}8)-polysialic acid which were affinity purified and coupled to Sepharose 4B. The sodium channel was found to bind to WGA, LFA, and IgM resins and was readily eluted with the appropriate soluble carbohydrates. Experiments with LFA and IgM resins demonstrated binding and unbinding rates and displacement kinetics, which suggest highly specific binding at multiple sites on the sodium channel protein. In preparative-scale purification of protein previously fractionated by anion-exchange chromatography, without stabilizing TTX, high yields were reproducibly obtained. Further, when detergent extracts were prepared from electroplax membranes fractionated by low-speed sedimentation, a single step over the IgM resin provided a 70-fold purification, yielding specific activities of 3,200 pmol of ({sup 3}H)TTX-binding sites/mg of protein and a single polypeptide of {approximately}285,000 Da on SDS-acrylamide gels. No small peptides were observed after this 5-h isolation. The authors describe a cation-dependent stabilization with millimolar levels of monovalent and micromolar levels of divalent species.

  14. Influence of ozone and paracetic acid disinfection on adhesion of resilient liners to acrylic resin

    Science.gov (United States)

    2016-01-01

    PURPOSE The aim of this study was to evaluate the effect of paracetic acid (PAA) and ozone disinfection on the tensile bond strength (TBS) of silicone-based resilient liners to acrylic resins. MATERIALS AND METHODS One hundred and twenty dumbbell shaped heat-polymerized acrylic resins were prepared. From the mid segment of the specimens, 3 mm of acrylic were grinded off and separated parts were reattached by resilient liners. The specimens were divided into 2 control (control1, control7) and 4 test groups of PAA and ozone disinfection (PAA1, PAA7, ozone1 and ozone7; n=10). While control groups were immersed in distilled water for 10 min (control1) and 7 days (control7), test groups were subjected to PAA (16 g/L) or ozone rich water (4 mg/L) for 1 cycle (10 min for PAA and 60 min for ozone) per day for 7 days prior to tensile tests. Measurements of the TBS were analyzed using 3-way ANOVA and Tukey's HSD test. RESULTS Adhesive strength of Mollosil decreased significantly by application of ozone disinfection. PAA disinfection had no negative effect on the TBS values of Mollosil and Molloplast B to acrylic resin. Single application of ozone disinfection did not have any negative effect on TBS values of Molloplast B, but prolonged exposure to ozone decreased its adhesive strength. CONCLUSION The adhesion of resilient liners to acrylic was not adversely affected by PAA disinfection. Immersion in ozonated water significantly decreased TBS of Mollosil. Prolonged exposure to ozone negatively affects adhesion of Molloplast B to denture base materials. PMID:27555898

  15. The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by C-13-labeling experiments

    DEFF Research Database (Denmark)

    Jensen, N.B.S.; Christensen, B.; Nielsen, Jette

    2002-01-01

    Uniformly C-13 labeled glucose was fed to a lactic acid bacterium growing on a defined medium supplemented with all proteinogenic amino acids except glutamate. Aspartate stemming from the protein pool and from the extracellular medium was enriched with C-13 disclosing a substantial de novo...... biosynthesis of this amino acid simultaneous to its uptake from the growth medium and a rapid exchange flux of aspartate over the cellular membrane. Phenylalanine, alanine, and threonine were also synthesized de novo in spite of their presence in the growth medium....

  16. Stability of two resin combinations used as sealants against toothbrush abrasion and acid challenge in vitro.

    Science.gov (United States)

    Yetkiner, Enver; Wegehaupt, Florian Just; Attin, Rengin; Wiegand, Annette; Attin, Thomas

    2014-11-01

    To test the stability of two conventional adhesives when combined with a low-viscosity caries infiltrant used for sealing sound enamel against toothbrush abrasion and acid challenge in vitro. Bovine enamel discs (Ø = 3 mm) randomly assigned to three groups (n = 10/group) were etched with 37% phosphoric acid for 30 s and treated with resins of different monomer contents forming three test groups: (1) Untreated specimens (Control); (2) Infiltrant (Icon, DMG) + conventional enamel bonding adhesive (Heliobond, Ivoclar Vivadent); and (3) Infiltrant + conventional orthodontic adhesive (Transbond XT Primer, 3M Unitek). All specimens were immersed in hydrochloric acid (pH 2.6) for up to 9 days, during which they were exposed to 1825 toothbrush-strokes per day. Calcium dissolution was assessed using Arsenazo III method at 24-h intervals. Data were analyzed by Kruskal-Wallis and Wilcoxon signed ranks tests. Cumulative calcium dissolution for the untreated specimens (39.75 ± 7.32 μmol/ml) exceeded the sealed groups (Icon + Heliobond: 23.44 ± 7.03 μmol/ml; Icon + Transbond XT Primer: 22.17 ± 5.34 μmol/ml). Untreated specimens presented a relatively constant calcium dissolution rate throughout the experimental period, whereas the sealed groups presented a gradual increase indicating weakening of the seal by toothbrush abrasion. Both sealed groups presented significantly lower daily calcium dissolution at all time points compared to the control, except for Group 2 on the last measurement day. Low-viscosity caries infiltrant application on sound enamel prior to conventional resin application provided a protective effect against enamel demineralization, but this effect was not stable when challenged mechanically by toothbrush abrasion.

  17. Ion-exchange Resin Catalyzed Esterification of Lactic Acid with Isopropanol: a Kinetic Study

    Directory of Open Access Journals (Sweden)

    Amrit P. Toor

    2011-05-01

    Full Text Available The kinetic behavior of esterification of lactic acid with isopropanol over an acidic cation exchange resin, Amberlyst 15, was studied under isothermal condition. Isopropyl lactate synthesized in this reaction is an important pharmaceutical intermediate. The experiments were carried out in a stirred batch reactor in the temperature range of 323.15 to 353.15 K. The effect of various parameters such as temperature, molar ratio and catalyst loading was studied. Variation in parameters on rate of reaction demonstrated that the reaction was intrinsically controlled. Kinetic modeling was performed using Eley-Rideal model which acceptably fits the experimental data. The activation energy was found to be 22.007 kJ/mol and frequency factor was 0.036809 l2 g-1 mol-1 min-1 for forward reaction. The value of entropy for the forward reaction was found to be 182.317 J K-1 mol-1 . © 2011 BCREC UNDIP. All rights reserved(Received: 19th January 2011, Revised: 16th March 2011; Accepted: 16th March 2011[How to Cite: A.P. Toor, M. Sharma, S. Thakur, and R. K. Wanchoo. (2011. Ion-exchange Resin Catalyzed Esterification of Lactic Acid with Isopropanol: a Kinetic Study. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 39-45. doi:10.9767/bcrec.6.1.791.39-45][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.791.39-45 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/791 ] | View in  

  18. Novel bioactive polyester scaffolds prepared from unsaturated resins based on isosorbide and succinic acid

    Energy Technology Data Exchange (ETDEWEB)

    Śmiga-Matuszowicz, Monika, E-mail: monika.smiga-matuszowicz@polsl.pl [Silesian University of Technology, Department of Physical Chemistry and Technology of Polymers, M. Strzody Street 9, 44-100 Gliwice (Poland); Janicki, Bartosz; Jaszcz, Katarzyna; Łukaszczyk, Jan [Silesian University of Technology, Department of Physical Chemistry and Technology of Polymers, M. Strzody Street 9, 44-100 Gliwice (Poland); Kaczmarek, Marcin [Silesian University of Technology, Department of Biomaterials and Medical Devices Engineering, de Gaulle' a Street 66, 41-800 Zabrze (Poland); Lesiak, Marta; Sieroń, Aleksander L. [Medical University of Silesia, Department of General and Molecular Biology and Genetics, Medyków Street 18, 40-752 Katowice (Poland); Simka, Wojciech [Silesian University of Technology, Department of Chemistry, Inorganic Technology and Fuels, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Mierzwiński, Maciej; Kusz, Damian [Medical University of Silesia, Department of Orthopedics and Traumatology, Ziołowa Street 45, 40-635 Katowice (Poland)

    2014-12-01

    In this study new biodegradable materials obtained by crosslinking poly(3-allyloxy-1,2-propylene succinate) (PSAGE) with oligo(isosorbide maleate) (OMIS) and small amount of methyl methacrylate were investigated. The porous scaffolds were obtained in the presence of a foaming system consisted of calcium carbonate/carboxylic acid mixture, creating in situ porous structure during crosslinking of liquid formulations. The maximum crosslinking temperature and setting time, the cured porous materials morphology as well as the effect of their porosity on mechanical properties and hydrolytic degradation process were evaluated. It was found that the kind of carboxylic acid used in the foaming system influenced compressive strength and compressive modulus of porous scaffolds. The MTS cytotoxicity assay was carried out for OMIS using hFOB1.19 cell line. OMIS resin was found to be non-toxic in wide range of concentrations. On the ground of scanning electron microscopy (SEM) observations and energy X-ray dispersive analysis (EDX) it was found that hydroxyapatite (HA) formation at the scaffolds surfaces within short period of soaking in phosphate buffer solution occurs. After 3 h immersion a compact layer of HA was observed at the surface of the samples. The obtained results suggest potential applicability of resulted new porous crosslinked polymeric materials as temporary bone void fillers. - Highlights: • Isosorbide-based resin was used as a component of biodegradable scaffolds. • CAC/carboxylic acid system was proven as facile method to obtain porous scaffolds. • Porous scaffolds displayed the formation of hydroxyapatite at their surfaces.

  19. Impact of pH and application time of meta-phosphoric acid on resin-enamel and resin-dentin bonding.

    Science.gov (United States)

    Cardenas, A F M; Siqueira, F S F; Bandeca, M C; Costa, S O; Lemos, M V S; Feitora, V P; Reis, A; Loguercio, A D; Gomes, J C

    2018-02-01

    To evaluate the immediate microshear resin-enamel bond strength (μSBS) and the immediate and 6-month microtensile bond strength (μTBS) and nanoleakage (NL) of the adhesive interface performed by different pHs of 40% meta-phosphoric acid (MPA) were compared with conventional 37% ortho-phosphoric acid (OPA) under different application times. Additionally, the enamel etching patterns were evaluated and the chemical/morphological changes induced by these differents groups were evaluated. One hundred and ninety-eight extracted human molars were randomly assigned into experimental groups according to the combination of independent variables: Acid [37% ortho-phosphoric acid (OPA), 40% meta-phosphoric acid (MPA) at pHs of: 0.5, 1 and 2] and Application Time [7, 15 and 30s]. Enamel-bond specimens were prepared and tested under μSBS. Resin-dentin beams were tested under μTBS tested immediately or after 6-months of water storage. Nanoleakage was evaluated using bonded-beams of each tooth/time-period. Enamel etching pattern and chemical and ultra-morphology analyses were also performed. The μSBS (MPa) data were subjected to a two-way repeated measures ANOVA (Acid vs. Application time). For μTBS, Acid vs application time vs storage time data were subjected to three-way ANOVA and Tukey's test (α = 0.05). MPA pH 0.5 showed μTBS similar to OPA, independently of the application time on enamel (p>0.05) or dentin (p>0.05). OPA provided higher nanoleakage values than MPA (p = 0.003). Significant decreases in TBS and increases in NL were only observed for OPA after 6 months (p = 0.001). An increase in the application time resulted in a more pronounced etching pattern for MPA. Chemical analysis showed that dentin demineralized by MPA depicted peaks of brushite and octacalcium phosphate. MPA exposed less collagen than OPA. However, optimal results for MPA were dependent on pH/application time. The use of 40% meta-phosphoric acid with a pH of 0.5 is an alternative acid

  20. Co-culture engineering for microbial biosynthesis of 3-amino-benzoic acid in Escherichia coli.

    Science.gov (United States)

    Zhang, Haoran; Stephanopoulos, Gregory

    2016-07-01

    3-amino-benzoic acid (3AB) is an important building block molecule for production of a wide range of important compounds such as natural products with various biological activities. In the present study, we established a microbial biosynthetic system for de novo 3AB production from the simple substrate glucose. First, the active 3AB biosynthetic pathway was reconstituted in the bacterium Escherichia coli, which resulted in the production of 1.5 mg/L 3AB. In an effort to improve the production, an E. coli-E. coli co-culture system was engineered to modularize the biosynthetic pathway between an upstream strain and an downstream strain. Specifically, the upstream biosynthetic module was contained in a fixed E. coli strain, whereas a series of E. coli strains were engineered to accommodate the downstream biosynthetic module and screened for optimal production performance. The best co-culture system was found to improve 3AB production by 15 fold, compared to the mono-culture approach. Further engineering of the co-culture system resulted in biosynthesis of 48 mg/L 3AB. Our results demonstrate co-culture engineering can be a powerful new approach in the broad field of metabolic engineering. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. COPI activity coupled with fatty acid biosynthesis is required for viral replication.

    Directory of Open Access Journals (Sweden)

    Sara Cherry

    2006-10-01

    Full Text Available During infection by diverse viral families, RNA replication occurs on the surface of virally induced cytoplasmic membranes of cellular origin. How this process is regulated, and which cellular factors are required, has been unclear. Moreover, the host-pathogen interactions that facilitate the formation of this new compartment might represent critical determinants of viral pathogenesis, and their elucidation may lead to novel insights into the coordination of vesicular trafficking events during infection. Here we show that in Drosophila cells, Drosophila C virus remodels the Golgi apparatus and forms a novel vesicular compartment, on the surface of which viral RNA replication takes place. Using genome-wide RNA interference screening, we found that this step in the viral lifecycle requires at least two host encoded pathways: the coat protein complex I (COPI coatamer and fatty acid biosynthesis. Our results integrate, clarify, and extend numerous observations concerning the cell biology of viral replication, allowing us to conclude that the coupling of new cellular membrane formation with the budding of these vesicles from the Golgi apparatus allows for the regulated generation of this new virogenic organelle, which is essential for viral replication. Additionally, because these pathways are also limiting in flies and in human cells infected with the related RNA virus poliovirus, they may represent novel targets for antiviral therapies.

  2. A natural protecting group strategy to carry an amino acid starter unit in the biosynthesis of macrolactam polyketide antibiotics.

    Science.gov (United States)

    Shinohara, Yuji; Kudo, Fumitaka; Eguchi, Tadashi

    2011-11-16

    Macrolactam antibiotics are an important class of macrocyclic polyketides that contain a unique nitrogen-containing starter unit. In the present study, a set of starter biosynthetic enzymes in the macrolactam antibiotic vicenistatin was characterized. We found that the protection-deprotection strategy of the aminoacyl-ACP intermediate was critical in this system. On the basis of bioinformatics, the described pathway is also proposed as a common method for carrying amino acids in the biosynthesis of other macrolactam antibiotics.

  3. Overexpression of the homologous lanosterol synthase gene in ganoderic acid biosynthesis in Ganoderma lingzhi.

    Science.gov (United States)

    Zhang, De-Huai; Li, Na; Yu, Xuya; Zhao, Peng; Li, Tao; Xu, Jun-Wei

    2017-02-01

    Ganoderic acids (GAs) in Ganoderma lingzhi exhibit anticancer and antimetastatic activities. GA yields can be potentially improved by manipulating G. lingzhi through genetic engineering. In this study, a putative lanosterol synthase (LS) gene was cloned and overexpressed in G. lingzhi. Results showed that its overexpression (OE) increased the ganoderic acid (GA) content and the accumulation of lanosterol and ergosterol in a submerged G. lingzhi culture. The maximum contents of GA-O, GA-Mk, GA-T, GA-S, GA-Mf, and GA-Me in transgenic strains were 46.6 ± 4.8, 24.3 ± 3.5, 69.8 ± 8.2, 28.9 ± 1.4, 15.4 ± 1.2, and 26.7 ± 3.1 μg/100 mg dry weight, respectively, these values being 6.1-, 2.2-, 3.2-, 4.8-, 2.0-, and 1.9-times higher than those in wild-type strains. In addition, accumulated amounts of lanosterol and ergosterol in transgenic strains were 2.3 and 1.4-fold higher than those in the control strains, respectively. The transcription level of LS was also increased by more than five times in the presence of the G. lingzhi glyceraldehyde-3-phosphate dehydrogenase gene promoter, whereas transcription levels of 3-hydroxy-3-methylglutaryl coenzyme A enzyme and squalene synthase did not change significantly in transgenic strains. This study demonstrated that OE of the homologous LS gene can enhance lanosterol accumulation. A large precursor supply promotes GA biosynthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Establishing a toolkit for precursor-directed polyketide biosynthesis: exploring substrate promiscuities of acid-CoA ligases.

    Science.gov (United States)

    Go, Maybelle Kho; Chow, Jeng Yeong; Cheung, Vivian Wing Ngar; Lim, Yan Ping; Yew, Wen Shan

    2012-06-05

    Polyketides are chemically diverse and medicinally important biochemicals that are biosynthesized from acyl-CoA precursors by polyketide synthases. One of the limitations to combinatorial biosynthesis of polyketides has been the lack of a toolkit that describes the means of delivering novel acyl-CoA precursors necessary for polyketide biosynthesis. Using five acid-CoA ligases obtained from various plants and microorganisms, we biosynthesized an initial library of 79 acyl-CoA thioesters by screening each of the acid-CoA ligases against a library of 123 carboxylic acids. The library of acyl-CoA thioesters includes derivatives of cinnamyl-CoA, 3-phenylpropanoyl-CoA, benzoyl-CoA, phenylacetyl-CoA, malonyl-CoA, saturated and unsaturated aliphatic CoA thioesters, and bicyclic aromatic CoA thioesters. In our search for the biosynthetic routes of novel acyl-CoA precursors, we discovered two previously unreported malonyl-CoA derivatives (3-thiophenemalonyl-CoA and phenylmalonyl-CoA) that cannot be produced by canonical malonyl-CoA synthetases. This report highlights the utility and importance of determining substrate promiscuities beyond conventional substrate pools and describes novel enzymatic routes for the establishment of precursor-directed combinatorial polyketide biosynthesis.

  5. P-HYDROXYPHENYLPYRUVATE DIOXYGENASE from Medicago sativa is involved in vitamin E biosynthesis and abscisic acid-mediated seed germination

    Science.gov (United States)

    Jiang, Jishan; Chen, Zhihong; Ban, Liping; Wu, Yudi; Huang, Jianping; Chu, Jinfang; Fang, Shuang; Wang, Zan; Gao, Hongwen; Wang, Xuemin

    2017-01-01

    P-HYDROXYPHENYLPYRUVATE DIOXYGENASE (HPPD) is the first committed enzyme involved in the biosynthesis of vitamin E, and is characterized by catalyzing the conversion of p-hydroxyphenyl pyruvate (HPP) to homogentisic acid (HGA). Here, an HPPD gene was cloned from Medicago sativa L. and designated MsHPPD, which was expressed at high levels in alfalfa leaves. PEG 6000 (polyethylene glycol), NaCl, abscisic acid and salicylic acid were shown to significantly induce MsHPPD expression, especially in the cotyledons and root tissues. Overexpression of MsHPPD was found to significantly increase the level of β-tocotrienol and the total vitamin E content in Arabidopsis seeds. Furthermore, these transgenic Arabidopsis seeds exhibited an accelerated germination time, compared with wild-type seeds under normal conditions, as well as under NaCl and ABA treatments. Meanwhile, the expression level of several genes associated with ABA biosynthesis (NCED3, NCED5 and NCED9) and the ABA signaling pathway (RAB18, ABI3 and ABI5) were significantly down-regulated in MsHPPD-overexpressing transgenic lines, as well as the total free ABA content. Taken together, these results demonstrate that MsHPPD functions not only in the vitamin E biosynthetic pathway, but also plays a critical role in seed germination via affecting ABA biosynthesis and signaling. PMID:28084442

  6. P-HYDROXYPHENYLPYRUVATE DIOXYGENASE from Medicago sativa is involved in vitamin E biosynthesis and abscisic acid-mediated seed germination.

    Science.gov (United States)

    Jiang, Jishan; Chen, Zhihong; Ban, Liping; Wu, Yudi; Huang, Jianping; Chu, Jinfang; Fang, Shuang; Wang, Zan; Gao, Hongwen; Wang, Xuemin

    2017-01-13

    P-HYDROXYPHENYLPYRUVATE DIOXYGENASE (HPPD) is the first committed enzyme involved in the biosynthesis of vitamin E, and is characterized by catalyzing the conversion of p-hydroxyphenyl pyruvate (HPP) to homogentisic acid (HGA). Here, an HPPD gene was cloned from Medicago sativa L. and designated MsHPPD, which was expressed at high levels in alfalfa leaves. PEG 6000 (polyethylene glycol), NaCl, abscisic acid and salicylic acid were shown to significantly induce MsHPPD expression, especially in the cotyledons and root tissues. Overexpression of MsHPPD was found to significantly increase the level of β-tocotrienol and the total vitamin E content in Arabidopsis seeds. Furthermore, these transgenic Arabidopsis seeds exhibited an accelerated germination time, compared with wild-type seeds under normal conditions, as well as under NaCl and ABA treatments. Meanwhile, the expression level of several genes associated with ABA biosynthesis (NCED3, NCED5 and NCED9) and the ABA signaling pathway (RAB18, ABI3 and ABI5) were significantly down-regulated in MsHPPD-overexpressing transgenic lines, as well as the total free ABA content. Taken together, these results demonstrate that MsHPPD functions not only in the vitamin E biosynthetic pathway, but also plays a critical role in seed germination via affecting ABA biosynthesis and signaling.

  7. SOLVENT EFFECTS IN THE LIQUID-PHASE HYDRATION OF CYCLOHEXENE CATALYZED BY A MACROPOROUS STRONG ACID ION-EXCHANGE RESIN

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1992-01-01

    The liquid-phase hydration of cyclohexene, a pseudo first order reversible reaction catalyzed by a strong acid ion exchange resin, macroporous Amberlite XE 307, was investigated in solvent mixtures of water and sulfolane. A decrease by a factor of 3 and 6 is observed in the experimentally measured

  8. Selective recovery of a pyridine derivative from an aqueous waste stream containing acetic acid and succinonitrile with solvent impregnated resins

    NARCIS (Netherlands)

    Bokhove, J.; Visser, T.J.; Schuur, Boelo; de Haan, A.B.

    2015-01-01

    Solvent impregnated resins (SIRs) were evaluated for the recovery of pyridine derivatives from an aqueous waste-stream containing also acetic acid and succinonitrile. For this purpose, a new solvent was developed, synthesized and impregnated in Amberlite XAD4. Sorption studies were used to determine

  9. Effect of Repeated Acid Challenges on the Color Stability of Resin-Infiltrated Enamel White Spot Lesions

    Science.gov (United States)

    2016-06-01

    seen in patients with xerostomia, poor oral hygiene, cariogenic diet, eating disorders , and orthodontic patients where bonded brackets provide... Effect of Repeated Acid Challenges on the Color Stability of Resin- Infiltrated Enamel White Spot Lesions by Robert A. Lummis...Jr. Lieutenant Commander, Dental Corps United States Public Health Service A thesis submitted to the Faculty of the Comprehensive

  10. Uranium loss from BISO-coated weak-acid-resin HTGR fuel

    International Nuclear Information System (INIS)

    Pearson, R.L.; Lindemer, T.B.

    1977-02-01

    Recycle fuel for the High-Temperature Gas-Cooled Reactor (HTGR) contains a weak-acid-resin (WAR) kernel, which consists of a mixture of UC 2 , UO 2 , and free carbon. At 1900 0 C, BISO-coated WAR UC 2 or UC 2 -UO 2 kernels lose a significant portion of their uranium in several hundred hours. The UC 2 decomposes and uranium diffuses through the pyrolytic coating. The rate of escape of the uranium is dependent on the temperature and the surface area of the UC 2 , but not on a temperature gradient. The apparent activation energy for uranium loss, ΔH, is approximately 90 kcal/mole. Calculations indicate that uranium loss from the kernel would be insignificant under conditions to be expected in an HTGR

  11. Low pressure process for continuous fiber reinforced polyamic acid resin matrix composite laminates

    Science.gov (United States)

    Druyun, Darleen A. (Inventor); Hou, Tan-Hung (Inventor); Kidder, Paul W. (Inventor); Reddy, Rakasi M. (Inventor); Baucom, Robert M. (Inventor)

    1994-01-01

    A low pressure processor was developed for preparing a well-consolidated polyimide composite laminate. Prepreg plies were formed from unidirectional fibers and a polyamic acid resin solution. Molding stops were placed at the sides of a matched metal die mold. The prepreg plies were cut shorter than the length of the mold in the in-plane lateral direction and were stacked between the molding stops to a height which was higher than the molding stops. The plies were then compressed to the height of the stops and heated to allow the volatiles to escape and to start the imidization reaction. After removing the stops from the mold, the heat was increased and 0 - 500 psi was applied to complete the imidization reaction. The heat and pressure were further increased to form a consolidated polyimide composite laminate.

  12. Selective Adsorption of Ag+ on a New Cyanuric-Thiosemicarbazide Chelating Resin with High Capacity from Acid Solutions

    Directory of Open Access Journals (Sweden)

    Guo Lin

    2017-11-01

    Full Text Available A new cyanuric-thiosemicarbazid (TSC-CC chelating resin was synthesized and employed to selectively adsorb Ag+ from acid solutions. The effects of acid concentration, initial concentration of Ag+, contact time and coexisting ions were investigated. The optimal acid concentration was 0.5 mol/L. The adsorption capacity of Ag+ reached 872.63 mg/g at acid concentration of 0.5 mol/L. The adsorption isotherm was fitted well with the Langmuir isotherm model and the kinetic data preferably followed the pseudo-second order model. The chelating resin showed a good selectivity for the Ag+ adsorption from acid solutions. Fourier transform infrared (FT-IR, X-ray diffraction (XRD, Scanning electron microscopy/energy dispersive spectrometer (SEM-EDS and X-ray photoelectron spectroscopy (XPS were used to study the adsorption mechanism. The chelating and ionic interaction was mainly adsorption mechanism. The adsorbent presents a great potential in selective recovery Ag+ from acid solutions due to the advantage of high adsorption capacity and adapting strongly acidic condition. The recyclability indicated that the (TSC-CC resin had a good stability and can be recycled as a promising agent for removal of Ag+.

  13. Improvement of epoxy resin properties by incorporation of TiO2 nanoparticles surface modified with gallic acid esters

    International Nuclear Information System (INIS)

    Radoman, Tijana S.; Džunuzović, Jasna V.; Jeremić, Katarina B.; Grgur, Branimir N.; Miličević, Dejan S.; Popović, Ivanka G.; Džunuzović, Enis S.

    2014-01-01

    Highlights: • Nanocomposites of epoxy resin and TiO 2 nanoparticles surface modified with gallates. • The T g of epoxy resin was increased by incorporation of surface modified TiO 2 . • WVTR of epoxy resin decreased in the presence of surface modified TiO 2 nanoparticles. • WVTR of nanocomposites was reduced with increasing gallates hydrophobic chain length. • Modified TiO 2 nanoparticles react as oxygen scavengers, inhibiting steel corrosion. - Abstract: Epoxy resin/titanium dioxide (epoxy/TiO 2 ) nanocomposites were obtained by incorporation of TiO 2 nanoparticles surface modified with gallic acid esters in epoxy resin. TiO 2 nanoparticles were obtained by acid catalyzed hydrolysis of titanium isopropoxide and their structural characterization was performed by X-ray diffraction and transmission electron microscopy. Three gallic acid esters, having different hydrophobic part, were used for surface modification of the synthesized TiO 2 nanoparticles: propyl, hexyl and lauryl gallate. The gallate chemisorption onto surface of TiO 2 nanoparticles was confirmed by Fourier transform infrared and ultraviolet–visible spectroscopy, while the amount of surface-bonded gallates was determined using thermogravimetric analysis. The influence of the surface modified TiO 2 nanoparticles, as well as the length of hydrophobic part of the gallate used for surface modification of TiO 2 nanoparticles, on glass transition temperature, barrier, dielectric and anticorrosive properties of epoxy resin was investigated by differential scanning calorimetry, water vapor transmission test, dielectric spectroscopy, electrochemical impedance spectroscopy and polarization measurements. Incorporation of surface modified TiO 2 nanoparticles in epoxy resin caused increase of glass transition temperature and decrease of the water vapor permeability of epoxy resin. The water vapor transmission rate of epoxy/TiO 2 nanocomposites was reduced with increasing hydrophobic part chain length of

  14. Influence of hydrofluoric acid on extraction of thorium using a commercially available extraction chromatographic resin.

    Science.gov (United States)

    Shimada-Fujiwara, Asako; Hoshi, Akiko; Kameo, Yutaka; Nakashima, Mikio

    2009-05-01

    The dependence of Th recovery on hydrofluoric acid (HF) concentration in nitric acid (HNO(3)) solutions (1-5 mol/dm(3)) containing 1x10(-6) mol/dm(3) of Th and various concentrations of HF and the elution behavior were studied using a commercially available UTEVA (for uranium and tetravalent actinide) resin column. Thorium recovery decreased with an increase in HF concentration in the sample solutions. The concentration of HF at which Th recovery started to decrease was approximately 1x10(-4) mol/dm(3) in 1 mol/dm(3) HNO(3) solution, approximately 1x10(-3) mol/dm(3) in 3 mol/dm(3) HNO(3) solution, and approximately 1x10(-2) mol/dm(3) in 5 mol/dm(3) HNO(3) solution. When Al(NO(3))(3) (0.2 mol/dm(3)) or Fe(NO(3))(3) (0.6 mol/dm(3)) was added as a masking agent for F(-) to the Th solution containing 1x10(-1) mol/dm(3) HF and 1 mol/dm(3) HNO(3), Th recovery improved from 1.4+/-0.3% to 95+/-5% or 93+/-3%. Effective extraction of Th using UTEVA resin was achieved by selecting the concentration of HNO(3) and/or adding masking agents such as Al(NO(3))(3) according to the concentration of HF in the sample solution.

  15. Releasing Pattern of Applied Phosphorus and Distribution Change of Phosphorus Fractions in the Acid Upland Soils with Successive Resin Extraction

    Directory of Open Access Journals (Sweden)

    Arief Hartono

    2008-05-01

    Full Text Available The releasing pattern of applied P in the acid upland soils and the soil properties influencing the pattern were studied. Surface horizons of six acid upland soils from Sumatra, Java and Kalimantan were used in this study. The releasing pattern of applied P (300 mg P kg-1 of these soils were studied by successive resin extraction. P fractionation was conducted to evaluate which fractions released P to the soil solution after successive resin extraction. The cumulative of resin-Pinorganic (Pi release of soils was fitted to the first order kinetic. Regression analyses using factor scores obtained from the previous principal components analyses was applied to determine soil properties influencing P releasing pattern. The results suggested that the maximum P release was significantly (P < 0.05 increased by acidity plus 1.4 nm mineral-related factor (PC2 i.e. exchangeable Al and 1.4 nm minerals (smectite and vermiculite and decreased by oxide related factor (PC1 i.e. aluminum (Al plus 1/2 iron (Fe (by ammonium oxalate, crystalline Al and Fe oxides, cation exchange capacity, and clay content. P fractionation analysis after successive resin extraction showed that both labile and less labile in the form of NaHCO3-Pi and NaOH-Pi fractions, respectively, can be transformed into resin-Pi when in the most labile resin-Pi is depleted. Most of P released in high oxides soils were from NaOH-Pi fraction while in low oxides soils were from NaHCO3-Pi. P release from the former fraction resulted in the maximum P release lower than that of the latter one. When NaHCO3-Pi was high, NaOH-Pi was relatively more stable than NaHCO3-Pi despite resin-Pi removal. NaHCO3-Pi and NaOH-Pi are very important P fractions in replenishing resin-Pi in these acid upland soils.

  16. Biogenic glutamic acid-based resin: Its synthesis and application in the removal of cobalt(II).

    Science.gov (United States)

    Jamiu, Zakariyah A; Saleh, Tawfik A; Ali, Shaikh A

    2017-04-05

    Inexpensive biogenic glutamic acid has been utilized to synthesize a cross-linked dianionic polyelectrolyte (CDAP) containing metal chelating ligands. Cycloterpolymerization, using azoisobutyronitrile as an initiator, of N,N-diallylglutamic acid hydrochloride, sulfur dioxide and a cross-linker afforded a pH-responsive cross-linked polyzwitterionic acid (CPZA) which upon basification with NaOH was converted into CDAP. The new resin, characterized by a multitude of spectroscopic techniques as well as Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analyses, was evaluated for the removal of Co(II) as a model case under different conditions. The adsorption capacity of 137mgg -1 does indeed make the resin as one of the most effective sorbents in recent times. The resin leverages its cheap natural source and ease of regeneration in combination with its high and fast uptake capacities to offer a great promise for wastewater treatment. The resin has demonstrated remarkable efficiency in removing toxic metal ions including arsenic from a wastewater sample. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Revealing complexity and specificity in the activation of lipase-mediated oxylipin biosynthesis: a specific role of the Nicotiana attenuata GLA1 lipase in the activation of jasmonic acid biosynthesis in leaves and roots.

    Science.gov (United States)

    Bonaventure, Gustavo; Schuck, Stefan; Baldwin, Ian T

    2011-09-01

    The activation of enzymatic oxylipin biosynthesis upon wounding, herbivory and pathogen attack depends on the biochemical activation of lipases that make polyunsaturated fatty acids (PUFAs) available to lipoxygenases (LOXs). The identity and number of the lipases involved in this process remain controversial and they probably differ among plant species. Analysis of transgenic Nicotiana attenuata plants (ir-gla1) stably reduced in the expression of the NaGLA1 gene showed that this plastidial glycerolipase is a major supplier of trienoic fatty acids for jasmonic acid (JA) biosynthesis in leaves and roots after wounding and simulated herbivory, but not during infection with the oomycete Phytophthora parasitica (var. nicotianae). NaGLA1 was not essential for the developmental control of JA biosynthesis in flowers and for the biosynthesis of C(6) volatiles by the hydroperoxide lyase (HPL) pathway; however, it affected the metabolism of divinyl ethers (DVEs) early during infection with P. parasitica (var. nicotianae) and the accumulation of NaDES1 and NaLOX1 mRNAs. Profiling of lysolipids by LC-MS/MS was consistent with a rapid activation of NaGLA1 and indicated that this lipase utilizes different lipid classes as substrates. The results revealed the complexity and specificity of the regulation of lipase-mediated oxylipin biosynthesis, highlighting the existence of pathway- and stimulus-specific lipases. © 2011 Blackwell Publishing Ltd.

  18. Inhibition of cholesterol biosynthesis in cultured fibroblasts by D003, a mixture of very long chain saturated fatty acids.

    Science.gov (United States)

    Menéndez, R; Más, R; Amor, A M; Rodeiros, I; Gonzalez, R M; Alfonso, J L

    2001-10-01

    The present study was undertaken to investigate the effects of D003, a mixture of very long chain saturated fatty acids isolated and purified from sugar cane wax, on cholesterol biosynthesis in cultured fibroblasts. Cholesterol biosynthesis is regulated through feedback regulation of at least two sequentially acting enzymes, 3-hydroxy-3-methyl coenzyme A (HMG-CoA) synthase and reductase. They are up-regulated when sterol levels fall and down-regulated when sterol levels rise. The exposure of cultured fibroblasts to a lipid-depleted medium (LDM) and D003 (0.05-50 microg ml(-1)) for 12 h inhibited, in a dose-dependent manner, cholesterol biosynthesis from 14C-labelled acetate (33-68%). The addition of D003 at concentrations inhibiting cholesterol biosynthesis from labelled acetate significantly decreased incorporation of radioactivity from 3H2O into sterols, but not from 14C-mevalonate. These data indicate that D003 inhibits cholesterol biosynthesis by interfering with early steps of cholesterol biosynthetic pathway. We reasoned that D003 acts directly on HMG-CoA reductase, the main regulatory enzyme of cholesterol biosynthetic pathway. However, when enzyme activity was measured in cell extracts in the presence of various concentrations of D003 (0.5-50 microg ml(-1)), reductase activity was not inhibited. Thus, there was no evidence for a competitive or non-competitive inhibition of enzyme activity by D003. Treatment with D003 significantly suppressed (68%) the enzyme up-regulation when cells were cultured in LDM, which suggests a depression of de novo synthesis of HMG-CoA reductase and/or a stimulation of its degradation. However, since the suppressive action of D003 on cholesterol biosynthesis was observed in metabolic conditions under which synthase up-regulation was also enhanced, we cannot rule out a possible effect of D003 on HMG-CoA synthase. Thus, further studies are needed to clarify the precise mechanism of the inhibitory effect of D003 on cholesterol

  19. A Unique Short-Chain Dehydrogenase/Reductase in Arabidopsis Glucose Signaling and Abscisic Acid Biosynthesis and Functions

    Science.gov (United States)

    Cheng, Wan-Hsing; Endo, Akira; Zhou, Li; Penney, Jessica; Chen, Huei-Chi; Arroyo, Analilia; Leon, Patricia; Nambara, Eiji; Asami, Tadao; Seo, Mitsunori; Koshiba, Tomokazu; Sheen, Jen

    2002-01-01

    Glc has hormone-like functions and controls many vital processes through mostly unknown mechanisms in plants. We report here on the molecular cloning of GLUCOSE INSENSITIVE1 (GIN1) and ABSCISIC ACID DEFICIENT2 (ABA2) which encodes a unique Arabidopsis short-chain dehydrogenase/reductase (SDR1) that functions as a molecular link between nutrient signaling and plant hormone biosynthesis. SDR1 is related to SDR superfamily members involved in retinoid and steroid hormone biosynthesis in mammals and sex determination in maize. Glc antagonizes ethylene signaling by activating ABA2/GIN1 and other abscisic acid (ABA) biosynthesis and signaling genes, which requires Glc and ABA synergistically. Analyses of aba2/gin1 null mutants define dual functions of endogenous ABA in inhibiting the postgermination developmental switch modulated by distinct Glc and osmotic signals and in promoting organ and body size and fertility in the absence of severe stress. SDR1 is sufficient for the multistep conversion of plastid- and carotenoid-derived xanthoxin to abscisic aldehyde in the cytosol. The surprisingly restricted spatial and temporal expression of SDR1 suggests the dynamic mobilization of ABA precursors and/or ABA. PMID:12417697

  20. Putrescine biosynthesis in Lactococcus lactis is transcriptionally activated at acidic pH and counteracts acidification of the cytosol.

    Science.gov (United States)

    Del Rio, Beatriz; Linares, Daniel; Ladero, Victor; Redruello, Begoña; Fernandez, Maria; Martin, Maria Cruz; Alvarez, Miguel A

    2016-11-07

    Lactococcus lactis subsp. cremoris CECT 8666 is a lactic acid bacterium that synthesizes the biogenic amine putrescine from agmatine via the agmatine deiminase (AGDI) pathway. The AGDI genes cluster includes aguR. This encodes a transmembrane protein that functions as a one-component signal transduction system, the job of which is to sense the agmatine concentration of the medium and accordingly regulate the transcription of the catabolic operon aguBDAC. The latter encodes the proteins necessary for agmatine uptake and its conversion into putrescine. This work reports the effect of extracellular pH on putrescine biosynthesis and on the genetic regulation of the AGDI pathway. Increased putrescine biosynthesis was detected at acidic pH (pH5) compared to neutral pH. Acidic pH induced the transcription of the catabolic operon via the activation of the aguBDAC promoter PaguB. However, the external pH had no significant effect on the activity of the aguR promoter PaguR, or on the transcription of the aguR gene. The transcriptional activation of the AGDI pathway was also found to require a lower agmatine concentration at pH5 than at neutral pH. Finally, the following of the AGDI pathway counteracted the acidification of the cytoplasm under acidic external conditions, suggesting it to provide protection against acid stress. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Amino acid metabolism of Astacus leptodactylus Esch.—III. Studies on the biosynthesis of α- and β-alanine from aspartate

    NARCIS (Netherlands)

    Marrewijk, W.J.A. van; Zandee, D.I.

    1975-01-01

    1. 1. Six hours after injection of 1- or 4-14C-aspartate into the crayfish Astacus leptodactylus almost all radioactivity incorporated was found in the amino acids. 2. 2. From both precursors only the amino acids α-alanine and glutamic acid were labelled. The biosynthesis of α-alanine from

  2. Differently localized lysophosphatidic acid acyltransferases crucial for triacylglycerol biosynthesis in the oleaginous alga Nannochloropsis.

    Science.gov (United States)

    Nobusawa, Takashi; Hori, Koichi; Mori, Hiroshi; Kurokawa, Ken; Ohta, Hiroyuki

    2017-05-01

    The production of renewable bioenergy will be necessary to meet rising global fossil fuel demands. Members of the marine microalgae genus Nannochloropsis produce large quantities of oils (triacylglycerols; TAGs), and this genus is regarded as one of the most promising for biodiesel production. Recent genome sequencing and transcriptomic studies on Nannochloropsis have provided a foundation for understanding its oleaginous trait, but the mechanism underlying oil accumulation remains to be clarified. Here we report Nannochloropsis knock-out strains of four extraplastidic lysophosphatidic acid acyltransferases (LPAT1-LPAT4) that catalyze a major de novo biosynthetic step of TAGs and membrane lipids. We found that the four LPATs are differently involved in lipid metabolic flow in Nannochloropsis. Double knock-outs among the LPATs revealed the pivotal LPATs for TAG biosynthesis, and localization analysis indicated that the stramenopile-specific LPATs (LPAT3 and LPAT4) associated with TAG synthesis reside at the perimeter of lipid droplets. No homologous region has been found with other lipid droplet-associated proteins, however. Lipid droplets are an organelle found in nearly all organisms, and recently they were shown to play important roles in cellular metabolism and signaling. Our results provide direct evidence for the importance of the perimeter of lipid droplet in TAG synthesis in addition to its known role in maintaining TAG stability, and these findings suggest that the oleaginous trait of Nannochloropsis is enabled by the acquisition of LPATs at the perimeter of lipid droplets. © 2017 The Authors. The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.

  3. Fabrication of micro-dot arrays and micro-walls of acrylic acid/melamine resin on aluminum by AFM probe processing and electrophoretic coating

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, S.; Kikuchi, T.; Sakairi, M. [Graduate School of Engineering, Hokkaido University, N-13, W-8, Kita-Ku, Sapporo 060-8628 (Japan); Takahashi, H. [Graduate School of Engineering, Hokkaido University, N-13, W-8, Kita-Ku, Sapporo 060-8628 (Japan)], E-mail: takahasi@elechem1-mc.eng.hokudai.ac.jp

    2008-11-30

    Micro-dot arrays and micro-walls of acrylic acid/melamine resin were fabricated on aluminum by anodizing, atomic force microscope (AFM) probe processing, and electrophoretic deposition. Barrier type anodic oxide films of 15 nm thickness were formed on aluminum and then the specimen was scratched with an AFM probe in a solution containing acrylic acid/melamine resin nano-particles to remove the anodic oxide film locally. After scratching, the specimen was anodically polarized to deposit acrylic acid/melamine resin electrophoretically at the film-removed area. The resin deposited on the specimen was finally cured by heating. It was found that scratching with the AFM probe on open circuit leads to the contamination of the probe with resin, due to positive shifts in the potential during scratching. Scratching of the specimen under potentiostatic conditions at -1.0 V, however, resulted in successful resin deposition at the film-removed area without probe contamination. The rate of resin deposition increased as the specimen potential becomes more positive during electrophoretic deposition. Arrays of resin dots with a few to several tens {mu}m diameter and 100-1000 nm height, and resin walls with 100-1000 nm height and 1 {mu}m width were obtained on specimens by successive anodizing, probe processing, and electrophoretic deposition.

  4. Amino Acids in the TM4-TM5 loop of Na,K-ATPase Are Important for Biosynthesis

    DEFF Research Database (Denmark)

    Jørgensen, Jesper Roland; Houghton-Larsen, Jens; Jacobsen, Mette Dorph

    2003-01-01

    in the endoplasmic reticulum quality control, as the same loop is responsible for the a-ß-associations required to leave this compartment. On the basis of the Ca-ATPase crystal structure and the presented data, we propose a model to account for the role of the TM4-TM5 loop in Na,K-ATPase biosynthesis.......The ten-transmembrane Na,K-ATPase a-subunit exposes very few amino acids to the extra membrane space except for an approximately 408 residue-long loop between transmembrane segments four and five. The present paper focuses on the role of this loop in biosynthesis of functional Na,K-ATPase...

  5. Biosynthesis of vitamins and enzymes in fermented foods by lactic acid bacteria and related genera - A promising approach

    Directory of Open Access Journals (Sweden)

    Ami Patel

    2013-01-01

    Full Text Available Lactic acid bacteria (LAB are widely employed in food fermentation processes for the biosynthesis of certain important products or metabolites. Fermented food provides plenty of vital nutrients and bioactive components that affect a number of functions of human body in a positive way. Fermented milks can be made more functional by incorporating probiotic strains and furthermore, if they are capable of synthesizing essential biomolecules such as vitamins, enzymes, exopolysaccharides, bacteriocins or bioactive peptides serve into the functional and technological properties of the products. Current paper reviews recent advances associated with biosynthesis of vitamins and enzymes by virtue of LAB and related genera. The outcomes of several studies indicate promising applications at commercial level; however adequate selection of strain is vital to increase the concentration and bioavailability of such biomolecules in fermented foods.

  6. trans-Cinnamic and Chlorogenic Acids Affect the Secondary Metabolic Profiles and Ergosterol Biosynthesis by Fusarium culmorum and F. graminearum Sensu Stricto.

    Science.gov (United States)

    Kulik, Tomasz; Stuper-Szablewska, Kinga; Bilska, Katarzyna; Buśko, Maciej; Ostrowska-Kołodziejczak, Anna; Załuski, Dariusz; Perkowski, Juliusz

    2017-06-22

    Plant-derived compounds limiting mycotoxin contamination are currently of major interest in food and feed production. However, their potential application requires an evaluation of their effects on fungal secondary metabolism and membrane effects. In this study, different strains of Fusarium culmorum and F. graminearum sensu stricto were exposed to trans -cinnamic and chlorogenic acids on solid YES media. Fusaria produced phenolic acids, whose accumulation was lowered by exogenous phenolic compounds. In addition, fungi reduced exogenous phenolic acids, leading either to their conversion or degradation. trans -Cinnamic acid was converted to caffeic and ferulic acids, while chlorogenic acid was degraded to caffeic acid. The latter underwent further degradation to protocatechuic acid. Fungal-derived trans -cinnamic acid, as the first intermediate of the shikimate pathway, increased after chlorogenic acid treatment, presumably due to the further inhibition of the conversion of trans -cinnamic acid. Exogenous trans -cinnamic and chlorogenic acid displayed the inhibition of mycotoxin production by Fusaria, which appeared to be largely dependent on the phenolic compound and its concentration and the assayed strain. Exogenous phenolic acids showed different effects on ergosterol biosynthesis by fungi. It was found that the production of this membrane sterol was stimulated by trans -cinnamic acid, while chlorogenic acid negatively impacted ergosterol biosynthesis, suggesting that phenolic acids with stronger antifungal activities may upregulate ergosterol biosynthesis by Fusaria. This paper reports on the production of phenolic acids by Fusaria for the first time.

  7. Characterization of hydroxybenzoic acid chelating resins: equilibrium, kinetics, and isotherm profiles for Cd(II and Pb(II uptake

    Directory of Open Access Journals (Sweden)

    BHAVNA A. SHAH

    2011-06-01

    Full Text Available Chelating ion-exchange resins were synthesized by polycondensation of ortho/para hydroxybenzoic acid with resorcinol/catechol employing formaldehyde as cross-linking agent at 80±5 °C in DMF. The resins were characterized by FTIR and XRD. The uptake behaviour of synthesized resins for Cd(II and Pb(II ions have been studied depending on contact time, pH, metal ion concentration and temperature. The sorption data obtained at optimized conditions were analyzed by the Langmuir and Freundlich isotherms. Experimental data of all metal–resin system were best represented by the Freundlich isotherm. The maximum obtained sorption capacity for cadmium was 69.53 mg g-1 and 169.32 mg g-1 for Lead. The adsorption process follows first order kinetics and the specific rate constant Kr was obtained by the application of the Lagergan equation. Thermodynamic parameters ∆Gads, ∆Sads and ∆Hads were calculated for the metal–resin systems. The external diffusion rate constant (KS and the intra-particle diffusion rate constant (Kid were calculated by the Spahn–Schlunder and Weber–Morris models, respectively. The sorption process was found to follow an intra-particle diffusion phenomenon.

  8. Separation of Technetium in Nitric Acid Solution With an Extractant Impregnated Resin

    International Nuclear Information System (INIS)

    Jei Kwon Moon; Eil Hee Lee; Chong-Hun Jung; Byung Chul Lee

    2006-01-01

    An extractant impregnated resin (EIR) was prepared by impregnation of Aliquat 336 into Amberlite XAD-4 for separation of technetium from rhodium in nitric acid solution. The prepared EIR showed high preference for rhenium (chemical analogue of technetium) over rhodium. The adsorption isotherms for rhenium were described well by Langmuir equation in both the single and multi-component systems. Maximum adsorption capacities obtained by modelling the isotherms of rhenium were 2.01 meq g -1 and 1.97 meq g -1 for the single and the multi-component systems, respectively. Column tests were also performed to confirm the separation efficiency of rhenium using a jacketed glass column (diam. 11 x L 150). The EIR column showed successful separation of rhenium with the breakthrough volume of about 122 BV for the breakthrough concentration of 0.08. Also the breakthrough data were modelled successfully by assuming a homogeneous diffusion model in the particle phase. The diffusivities obtained from the modelling were in the order of 10 -7 cm 2 min -1 for a rhenium. The rhenium adsorbed on the bed could be eluted with a high purity by using a nitric acid solution. (authors)

  9. Establishment of a yeast platform strain for production of p-coumaric acid through metabolic engineering of aromatic amino acid biosynthesis

    DEFF Research Database (Denmark)

    Rodriguez Prado, Edith Angelica; Kildegaard, Kanchana Rueksomtawin; Li, Mingji

    2015-01-01

    Aromatic amino acids are precursors of numerous plant secondary metabolites with diverse biological functions. Many of these secondary metabolites are already being used as active pharmaceutical or nutraceutical ingredients, and there are numerous exploratory studies of other compounds...... with promising applications. p-Coumaric acid is derived from aromatic amino acids and, besides being a valuable chemical building block, it serves as precursor for biosynthesis of many secondary metabolites, such as polyphenols, flavonoids, and some polyketides. Here we developed a p-coumaric acid...... as another important flux-controlling step in the aromatic amino acid pathway by overexpressing enzymes from Escherichia coli, homologous to the pentafunctional enzyme Aro1p and to the bifunctional chorismate synthase-flavin reductase Aro2p. The highest titer of p-coumaric acid of 1.93±0.26 g L−1...

  10. Abietic acid isolated from pine resin (Resina Pini) enhances angiogenesis in HUVECs and accelerates cutaneous wound healing in mice.

    Science.gov (United States)

    Park, Jun Yeon; Lee, Yun Kyung; Lee, Dong-Soo; Yoo, Jeong-Eun; Shin, Myoung-Sook; Yamabe, Noriko; Kim, Su-Nam; Lee, Seulah; Kim, Ki Hyun; Lee, Hae-Jeung; Roh, Seok Sun; Kang, Ki Sung

    2017-05-05

    Resin known as Resina Pini is listed in the Korean and Japanese pharmacopoeias and has been used for treating skin wounds and inflammation. Resin is composed of more than 50% abietic acid and 10% neutral substances. In the present study, the wound-healing effects of abietic acid and the possible underlying mechanism of action were investigated in various in vitro and in vivo models. The effects of abietic acid on tube formation and migration were measured in human umbilical vein vascular endothelial cells (HUVECs). Protein expression of mitogen-activated protein kinase (MAPK) activation was evaluated via Western blotting analysis. The wound-healing effects of abietic acid were assessed using a mouse model of cutaneous wounds. The results showed that abietic acid enhanced cell migration and tube formation in HUVECs. Abietic acid induced significant angiogenic potential, which is associated with upregulation of extracellular signal-regulated kinase (ERK) and p38 expression. Additionally, 0.8μM abietic acid-treated groups showed accelerated wound closure compared to the controls in a mouse model of cutaneous wounds. The current data indicate that abietic acid treatment elevated cell migration and tube formation in HUVECs by the activation of ERK and p38 MAPKs. We suggest that abietic acid can be developed as a wound-healing agent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Surface Engineering of PAMAM-SDB Chelating Resin with Diglycolamic Acid (DGA) Functional Group for Efficient Sorption of U(VI) and Th(IV) from Aqueous Medium

    Energy Technology Data Exchange (ETDEWEB)

    Ilaiyaraja, P.; Venkatraman, B., E-mail: chemila07@gmail.com [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Deb, A.K. Singha [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India); Ponraju, D. [Safety Engineering Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Ali, Sk. Musharaf [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

    2017-04-15

    Highlights: • A new DGA-PAMAM-SDB chelating resin has been synthesized for actinide sorption. • Maximum sorption capacities of resin are 682 and 544.2 mg g{sup −1}for U(VI) and Th(IV). • DGA-PAMAM-SDB chelating resin could be regenerated and reused. • DFT calculation of actinides interaction with resin corroborates the experimental. • Resin is effective for sorption of actinides from both aqueous and HNO{sub 3} medium. - Abstract: A novel chelating resin obtained via growth of PAMAM dendron on surface of styrene divinyl benzene resin beads, followed by diglycolamic acid functionalization of the dendrimer terminal. Batch experiments were conducted to study the effects of pH, nitric acid concentration, amount of adsorbent, shaking time, initial metal ion concentration and temperature on U(VI) and Th(IV) adsorption efficiency. Diglycolamic acid terminated PAMAM dendrimer functionalized styrene divinylbenzene chelating resin (DGA-PAMAM-SDB) is found to be an efficient candidate for the removal of U(VI) and Th(IV) ions from aqueous (pH > 4) and nitric acid media (> 3 M). The sorption equilibrium could be reached within 60 min, and the experimental data fits with pseudo-second-order model. Langmuir sorption isotherm model correlates well with sorption equilibrium data. The maximum U(VI) and Th(IV) sorption capacity onto DGA-PAMAMG{sub 5}-SDB was estimated to be about 682 and 544.2 mg g{sup −1} respectively at 25 °C. The interaction of actinides and chelating resin is reversible and hence, the resin can be regenerated and reused. DFT calculation on the interaction of U(VI) and Th(IV) ions with chelating resin validates the experimental findings.

  12. Reduction of polyester resin shrinkage by means of epoxy resin

    International Nuclear Information System (INIS)

    Pietrzak, M.; Brzostowski, A.

    1981-01-01

    An attempt was made to decrease the shrinkage of unsaturated polyester resin, taking place during radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified with cinnamic and acrylic acids. A composition of 90 parts of polyester resin, 10 parts of epoxy resin modified with cinnamic acid, and 150 parts of a silica filler showed a volume shrinkage of 1.2%. (author)

  13. Distribution of 14 elements from two solutions simulating Hanford HLW Tank 102-SY (acid-dissolved sludge and acidified supernate) on four cation exchange resins and five anion exchange resins having different functional groups

    International Nuclear Information System (INIS)

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1995-01-01

    As part of the Tank Waste Remediation System program at Los Alamos, we evaluated a series of cation exchange and anion exchange resins for their ability to remove hazardous components from radioactive high-level waste (HLW). The anion exchangers were Reillex TM HPQ, a polyvinyl pyridine resin, and four strong-base polystyrene resins having trimethyl, tri ethyl, tri propyl, and tributyl amine as their respective functional groups. The cation exchange resins included Amberlyst TM 15 and Amberlyst tM XN-1010 with sulfonic acid functionality, Duolite TM C-467 with phosphonic acid functionality, and poly functional Diphonix TM with di phosphonic acid, sulfonic acid, and carboxylic acid functionalities. We measured the distributions of 14 elements on these resins from solutions simulating acid-dissolved sludge (pH 0.6) and acidified supernate (pH 3.5) from underground storage tank 102-SY at the Hanford Reservation near Richland, Washington, USA. To these simulants, we added the appropriate radionuclides and used gamma spectrometry to measure fission products (Ce, Cs, Sr, Tc, and Y), actinides (U, Pu, and Am), and matrix elements (Cr, Co, Fe, Mn, Zn, and Zr). For each of the 252 element/resin/solution combinations, distribution coefficients (Kds) were measured for dynamic contact periods of 30 minutes, 2 hours, and 6 hours to obtain information about sorption kinetics from these complex media. Because we measured the sorption of many different elements, the tabulated results indicate which unwanted elements are most likely to interfere with the sorption of elements of special interest. On the basis of these 756 measured Kd values, we conclude that some of the tested resins appear suitable for partitioning hazardous components from Hanford HLW. (author). 10 refs., 11 tabs

  14. Endurance exercise and conjugated linoleic acid (CLA supplementation up-regulate CYP17A1 and stimulate testosterone biosynthesis.

    Directory of Open Access Journals (Sweden)

    Rosario Barone

    Full Text Available A new role for fat supplements, in particular conjugated linoleic acid (CLA, has been delineated in steroidogenesis, although the underlying molecular mechanisms have not yet been elucidated. The aims of the present study were to identify the pathway stimulated by CLA supplementation using a cell culture model and to determine whether this same pathway is also stimulated in vivo by CLA supplementation associated with exercise. In vitro, Leydig tumour rat cells (R2C supplemented with different concentrations of CLA exhibited increasing testosterone biosynthesis accompanied by increasing levels of CYP17A1 mRNA and protein. In vivo, trained mice showed an increase in free plasma testosterone and an up-regulation of CYP17A1 mRNA and protein. The effect of training on CYP17A1 expression and testosterone biosynthesis was significantly higher in the trained mice supplemented with CLA compared to the placebo. The results of the present study demonstrated that CLA stimulates testosterone biosynthesis via CYP17A1, and endurance training led to the synthesis of testosterone in vivo by inducing the overexpression of CYP17A1 mRNA and protein in the Leydig cells of the testis. This effect was enhanced by CLA supplementation. Therefore, CLA-associated physical activity may be used for its steroidogenic property in different fields, such as alimentary industry, human reproductive medicine, sport science, and anti-muscle wasting.

  15. Splice Variants of the Castor WRI1 Gene Upregulate Fatty Acid and Oil Biosynthesis When Expressed in Tobacco Leaves.

    Science.gov (United States)

    Ji, Xia-Jie; Mao, Xue; Hao, Qing-Ting; Liu, Bao-Ling; Xue, Jin-Ai; Li, Run-Zhi

    2018-01-05

    The plant-specific WRINKLED1 (WRI1) is a member of the AP2/EREBP class of transcription factors that positively regulate oil biosynthesis in plant tissues. Limited information is available for the role of WRI1 in oil biosynthesis in castor bean ( Ricinus connunis L.), an important industrial oil crop. Here, we report the identification of two alternatively spliced transcripts of RcWRI1 , designated as RcWRI1-A and RcWRI1-B . The open reading frames of RcWRI1-A (1341 bp) and RcWRI1-B (1332 bp) differ by a stretch of 9 bp, such that the predicted RcWRI1-B lacks the three amino acid residues "VYL" that are present in RcWRI1-A. The RcWRI1-A transcript is present in flowers, leaves, pericarps and developing seeds, while the RcWRI1-B mRNA is only detectable in developing seeds. When the two isoforms were individually introduced into an Arabidopsis wri1-1 loss-of-function mutant, total fatty acid content was almost restored to the wild-type level, and the percentage of the wrinkled seeds was largely reduced in the transgenic lines relative to the wri1-1 mutant line. Transient expression of each RcWRI1 splice isoform in N. benthamiana leaves upregulated the expression of the WRI1 target genes, and consequently increased the oil content by 4.3-4.9 fold when compared with the controls, and RcWRI1-B appeared to be more active than RcWRI1-A . Both RcWRI1-A and RcWRI1-B can be used as a key transcriptional regulator to enhance fatty acid and oil biosynthesis in leafy biomass.

  16. Fatty acid biosynthesis. VIII. The fate of malonyl-CoA in fatty acid biosynthesis by purified enzymes from lactating-rabbit mammary gland

    DEFF Research Database (Denmark)

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

    1971-01-01

    -CoA. - 3. The preparations of acetyl-CoA carboxylase and fatty acid synthetase were each able to decarboxylate [1,3-14C2]malonyl-CoA. - 4. Both enzyme preparations acted as competitive inhibitors of 14CO2 fixation into acetyl-CoA catalysed by acetyl-CoA carboxylase in the absence of NADPH...... acid synthesis by the presence of fatty acid synthetase and NADPH. The rate of fatty acid formation was equal to that of acetyl-CoA carboxylation, without the accumulation of free malonyl-CoA to a concentration required to obtain the same rate of fatty acid synthesis from added [1,3-14C2]malonyl...

  17. PgLOX6 encoding a lipoxygenase contributes to jasmonic acid biosynthesis and ginsenoside production in Panax ginseng.

    Science.gov (United States)

    Rahimi, Shadi; Kim, Yu-Jin; Sukweenadhi, Johan; Zhang, Dabing; Yang, Deok-Chun

    2016-11-01

    Ginsenosides, the valuable pharmaceutical compounds in Panax ginseng, are triterpene saponins that occur mainly in ginseng plants. It was shown that in vitro treatment with the phytohormone jasmonic acid (JA) is able to increase ginsenoside production in ginseng plants. To understand the molecular link between JA biosynthesis and ginsenoside biosynthesis, we identified a JA biosynthetic 13-lipoxygenase gene (PgLOX6) in P. ginseng that promotes ginsenoside production. The expression of PgLOX6 was high in vascular bundles, which corresponds with expression of ginsenoside biosynthetic genes. Consistent with the role of PgLOX6 in synthesizing JA and promoting ginsenoside synthesis, transgenic plants overexpressing PgLOX6 in Arabidopsis had increased amounts of JA and methyl jasmonate (MJ), increased expression of triterpene biosynthetic genes such as squalene synthase (AtSS1) and squalene epoxidase (AtSE1), and increased squalene content. Moreover, transgenic ginseng roots overexpressing PgLOX6 had around 1.4-fold increased ginsenoside content and upregulation of ginsenoside biosynthesis-related genes including PgSS1, PgSE1, and dammarenediol synthase (PgDDS), which is similar to that of treatment with MJ. However, MJ treatment of transgenic ginseng significantly enhanced JA and MJ, associated with a 2.8-fold increase of ginsenoside content compared with the non-treated, non-transgenic control plant, which was 1.4 times higher than the MJ treatment effect on non-transgenic plants. These results demonstrate that PgLOX6 is responsible for the biosynthesis of JA and promotion of the production of triterpenoid saponin through up-regulating the expression of ginsenoside biosynthetic genes. This work provides insight into the role of JA in biosynthesizing secondary metabolites and provides a molecular tool for increasing ginsenoside production. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. Profiling and Quantifying Differential Gene Transcription Provide Insights into Ganoderic Acid Biosynthesis in Ganoderma lucidum in Response to Methyl Jasmonate

    Science.gov (United States)

    Shi, Liang; Mu, Da-Shuai; Jiang, Ai-Liang; Han, Qin; Zhao, Ming-Wen

    2013-01-01

    Ganoderma lucidum is a mushroom with traditional medicinal properties that has been widely used in China and other countries in Eastern Asia. Ganoderic acids (GA) produced by G. lucidum exhibit important pharmacological activities. Previous studies have demonstrated that methyl jasmonate (MeJA) is a potent inducer of GA biosynthesis and the expression of genes involved in the GA biosynthesis pathway in G. lucidum. To further explore the mechanism of GA biosynthesis, cDNA-Amplified Fragment Length Polymorphism (cDNA-AFLP) was used to identify genes that are differentially expressed in response to MeJA. Using 64 primer combinations, over 3910 transcriptionally derived fragments (TDFs) were obtained. Reliable sequence data were obtained for 390 of 458 selected TDFs. Ninety of these TDFs were annotated with known functions through BLASTX searching the GenBank database, and 12 annotated TDFs were assigned into secondary metabolic pathways by searching the KEGGPATHWAY database. Twenty-five TDFs were selected for qRT-PCR analysis to confirm the expression patterns observed with cDNA-AFLP. The qRT-PCR results were consistent with the altered patterns of gene expression revealed by the cDNA-AFLP technique. Additionally, the transcript levels of 10 genes were measured at the mycelium, primordia, and fruiting body developmental stages of G. lucidum. The greatest expression levels were reached during primordia for all of the genes except cytochrome b2 reached its highest expression level in the mycelium stage. This study not only identifies new candidate genes involved in the regulation of GA biosynthesis but also provides further insight into MeJA-induced gene expression and secondary metabolic response in G. lucidum. PMID:23762280

  19. Amalgamation of nucleosides and amino acids in antibiotic biosynthesis: discovery of an L-threonine:uridine-5'-aldehyde transaldolase.

    Science.gov (United States)

    Barnard-Britson, Sandra; Chi, Xiuling; Nonaka, Koichi; Spork, Anatol P; Tibrewal, Nidhi; Goswami, Anwesha; Pahari, Pallab; Ducho, Christian; Rohr, Jurgen; Van Lanen, Steven G

    2012-11-14

    The lipopeptidyl nucleoside antibiotics represented by A-90289, caprazamycin, and muraymycin are structurally highlighted by a nucleoside core that contains a nonproteinogenic β-hydroxy-α-amino acid named 5'-C-glycyluridine (GlyU). Bioinformatic analysis of the biosynthetic gene clusters revealed a shared open reading frame encoding a protein with sequence similarity to serine hydroxymethyltransferases, resulting in the proposal that this shared enzyme catalyzes an aldol-type condensation with glycine and uridine-5'-aldehyde to furnish GlyU. Using LipK involved in A-90289 biosynthesis as a model, we now functionally assign and characterize the enzyme responsible for the C-C bond-forming event during GlyU biosynthesis as an l-threonine:uridine-5'-aldehyde transaldolase. Biochemical analysis revealed this transformation is dependent upon pyridoxal-5'-phosphate, the enzyme has no activity with alternative amino acids, such as glycine or serine, as aldol donors, and acetaldehyde is a coproduct. Structural characterization of the enzyme product is consistent with stereochemical assignment as the threo diastereomer (5'S,6'S)-GlyU. Thus this enzyme orchestrates C-C bond breaking and formation with concomitant installation of two stereocenters to make a new l-α-amino acid with a nucleoside side chain.

  20. Neutral Lipid Biosynthesis in Engineered Escherichia coli: Jojoba Oil-Like Wax Esters and Fatty Acid Butyl Esters

    OpenAIRE

    Kalscheuer, Rainer; Stöveken, Tim; Luftmann, Heinrich; Malkus, Ursula; Reichelt, Rudolf; Steinbüchel, Alexander

    2006-01-01

    Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant E...

  1. The p450 monooxygenase BcABA1 is essential for abscisic acid biosynthesis in Botrytis cinerea

    DEFF Research Database (Denmark)

    Siewers, V.; Smedsgaard, Jørn; Tudzynski, P.

    2004-01-01

    The phytopathogenic ascomycete Botrytis cinerea is known to produce abscisic acid (ABA), which is thought to be involved in host-pathogen interaction. Biochemical analyses had previously shown that, in contrast to higher plants, the fungal ABA biosynthesis probably does not proceed via carotenoids...... but involves direct cyclization of farnesyl diphosphate and subsequent oxidation steps. We present here evidence that this "direct" pathway is indeed the only one used by an ABA-overproducing strain of B. cinerea. Targeted inactivation of the gene bccpr1 encoding a cytochrome P450 oxidoreductase reduced...

  2. SEPARATION AND PRECONCENTRATION OF COPPER (II ION BY FATTY HYDROXAMIC ACIDS IMMOBILIZED ONTO AMBERLITE XAD – 4 RESIN

    Directory of Open Access Journals (Sweden)

    Dedy Suhendra

    2010-06-01

    Full Text Available A method of copper (II ion preconcentration and separation from other ions by using a column containing fatty hydroxamic acids - loaded Amberlite XAD 4 resin (FHA-Amb is described. Several factors, which affect the separation and preconcentration efficiency such as pH, sample volume, and concentration of eluent and flow rate, have been investigated.  A quantitative recovery of copper (II ion from FHA-Amb resin column was obtained using 10% HNO3 solutions as eluent with a preconcentration factor of 60. A method for separation of Cu(II from Zn(II and Cd(II is proposed.  A rapid sample throughput, a clean separation, a high preconcentration factor and simplicity are the main advantages in these analytical procedures.   Keywords: extraction, preconcentration, fatty hydroxamic acid, copper (ii ion, amberlite XAD-4

  3. Activation of glycerol metabolic pathway by evolutionary engineering of Rhizopus oryzae to strengthen the fumaric acid biosynthesis from crude glycerol.

    Science.gov (United States)

    Huang, Di; Wang, Ru; Du, Wenjie; Wang, Guanyi; Xia, Menglei

    2015-11-01

    Rhizopus oryzae is strictly inhibited by biodiesel-based by-product crude glycerol, which results in low fumaric acid production. In this study, evolutionary engineering was employed to activate the glycerol utilization pathway for fumaric acid production. An evolved strain G80 was selected, which could tolerate and utilize high concentrations of crude glycerol to produce 14.9g/L fumaric acid with a yield of 0.248g/g glycerol. Key enzymes activity analysis revealed that the evolved strain displayed a significant upregulation in glycerol dissimilation, pyruvate consumption and reductive tricarboxylic acid pathways, compared with the parent strain. Subsequently, intracellular metabolic profiling analysis showed that amino acid biosynthesis, tricarboxylic acid cycle, fatty acid and stress response metabolites accounted for metabolic difference between two strains. Moreover, a glycerol fed-batch strategy was optimized to obtain the highest fumaric acid production of 25.5g/L, significantly increased by 20.9-fold than that of the parent strain of 1.2g/L. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Efficient in situ separation and production of L-lactic acid by Bacillus coagulans using weak basic anion-exchange resin.

    Science.gov (United States)

    Zhang, Yitong; Qian, Zijun; Liu, Peng; Liu, Lei; Zheng, Zhaojuan; Ouyang, Jia

    2018-02-01

    To get rid of the dependence on lactic acid neutralizer, a simple and economical approach for efficient in situ separation and production of L-lactic acid was established by Bacillus coagulans using weak basic anion-exchange resin. During ten tested resins, the 335 weak basic anion-exchange resins demonstrated the highest adsorption capacity and selectivity for lactic acid recovery. The adsorption study of the 335 resins for lactic acid confirmed that it is an efficient adsorbent under fermentation condition. Langmuir models gave a good fit to the equilibrium data at 50 °C and the maximum adsorption capacity for lactic acid by 335 resins was about 402 mg/g. Adsorption kinetic experiments showed that pseudo-second-order kinetics model gave a good fit to the adsorption rate. When it was used for in situ fermentation, the yield of L-lactic acid by B. coagulans CC17 was close to traditional fermentation and still maintained at about 82% even after reuse by ten times. These results indicated that in situ separation and production of L-lactic acid using the 335 resins were efficient and feasible. This process could greatly reduce the dosage of neutralizing agent and potentially be used in industry.

  5. Gas chromatographic determination of organic acids from fruit juices by combined resin mediated methylation and extraction in supercritical carbon dioxide.

    Science.gov (United States)

    Barden, T J; Croft, M Y; Murby, E J; Wells, R J

    1997-10-17

    A procedure in which anionic analytes, trapped on ion exchange resin, are simultaneously methylated and released using methyl iodide in either supercritical carbon dioxide or acetonitrile has been extended to polyfunctional organic acids. The combined SFE methylation of fruit juice acids trapped onto ion exchange resin proceeds in good yield producing the methyl esters of fumaric, succinic, malic, tartaric, isocitric and citric acids which are readily separated by GC. Using this procedure low concentrations of one acid can be detected and quantitated in the presence of very high concentrations of another. This new method detects tartaric acid at levels of 10 ppm in juices containing 10,000 ppm citric acid. Quantitation was performed either by using GC-FID with triethyl citrate or diethyl tartrate as internal standards or with the element specific calibration capability of the GC-AED. A simple new technique for the determination of citric/isocitric acid ratio is now available. Also, in contrast to HPLC methods, the identity of an analyte is readily confirmed by GC-MS.

  6. Amino Acids Attenuate Insulin Action on Gluconeogenesis and Promote Fatty Acid Biosynthesis via mTORC1 Signaling Pathway in trout Hepatocytes

    Directory of Open Access Journals (Sweden)

    Weiwei Dai

    2015-06-01

    Full Text Available Background/Aims: Carnivores exhibit poor utilization of dietary carbohydrates and glucose intolerant phenotypes, yet it remains unclear what are the causal factors and underlying mechanisms. We aimed to evaluate excessive amino acids (AAs-induced effects on insulin signaling, fatty acid biosynthesis and glucose metabolism in rainbow trout and determine the potential involvement of mTORC1 and p38 MAPK pathway. Methods: We stimulated trout primary hepatocytes with different AA levels and employed acute administration of rapamycin to inhibit mTORC1 activation. Results: Increased AA levels enhanced the phosphorylation of ribosomal protein S6 kinase (S6K1, S6, and insulin receptor substrate 1 (IRS-1 on Ser302 but suppressed Akt and p38 phosphorylation; up-regulated the expression of genes related to gluconeogenesis and fatty acid biosynthesis. mTORC1 inhibition not only inhibited the phosphorylation of mTORC1 downstream targets, but also blunted IRS-1 Ser302 phosphorylation and restored excessive AAs-suppressed Akt phosphorylation. Rapamycin also inhibited fatty acid biosynthetic and gluconeogenic gene expression. Conclusion: High levels of AAs up-regulate hepatic fatty acid biosynthetic gene expression through an mTORC1-dependent manner, while attenuate insulin-mediated repression of gluconeogenesis through elevating IRS-1 Ser302 phosphorylation, which in turn impairs Akt activation and thereby weakening insulin action. We propose that p38 MAPK probably also involves in these AAs-induced metabolic changes.

  7. [Effect of hydrofluoric acid concentration on the surface morphology and bonding effectiveness of lithium disilicate glass ceramics to resin composites].

    Science.gov (United States)

    Hailan, Qian; Lingyan, Ren; Rongrong, Nie; Xiangfeng, Meng

    2017-12-01

    This study aimed at determining the influence of hydrofluoric acid (HF) in varied concentrations on the surface morphology of lithium disilicate glass ceramics and bond durability between resin composites and post-treated lithium disilicate glass ceramics. After being sintered, ground, and washed, 72 as-prepared specimens of lithium disilicate glass ceramics with dimensions of 11 mm×13 mm×2 mm were randomly divided into three groups. Each group was treated with acid solution [32% phosphoric acid (PA) or 4% or 9.5% HF] for 20 s. Then, four acidified specimens from each group were randomly selected. One of the specimens was used to observe the surface morphology using scanning electron microscopy, and the others were used to observe the surface roughness using a surface roughness meter (including Ra, Rz, and Rmax). After treatment with different acid solutions in each group, 20 samples were further treated with silane coupling agent/resin adhesive/resin cement (Monobond S/Multilink Primer A&B/Multilink N), followed by bonding to a composite resin column (Filtek™ Z350) with a diameter of 3 mm. A total of 20 specimens in each group were randomly divided into two subgroups, which were used for measuring the microshear bond strength, with one of them subjected to cool-thermal cycle for 20 000 times. The surface roughness (Ra, Rz, and Rmax) of lithium disilicate glass ceramics treated with 4% or 9.5% HF was significantly higher than that of the ceramic treated with PA (Pglass ceramics treated with 9.5% HF also demonstrated better surface roughness (Rz and Rmax) than that of the ceramics treated with 4% HF. Cool-thermal cycle treatment reduced the bond strength of lithium disilicate glass ceramics in all groups (Pglass ceramics treated with HF had higher bond strength than that of the ceramics treated with PA. The lithium disilicate glass ceramics treated with 4% HF had higher bond strength than that of the ceramics treated with 9.5% HF (Pglass ceramics treated with 4

  8. Sphingolipid biosynthesis upregulation by TOR complex 2-Ypk1 signaling during yeast adaptive response to acetic acid stress.

    Science.gov (United States)

    Guerreiro, Joana F; Muir, Alexander; Ramachandran, Subramaniam; Thorner, Jeremy; Sá-Correia, Isabel

    2016-12-01

    Acetic acid-induced inhibition of yeast growth and metabolism limits the productivity of industrial fermentation processes, especially when lignocellulosic hydrolysates are used as feedstock in industrial biotechnology. Tolerance to acetic acid of food spoilage yeasts is also a problem in the preservation of acidic foods and beverages. Thus understanding the molecular mechanisms underlying adaptation and tolerance to acetic acid stress is increasingly important in industrial biotechnology and the food industry. Prior genetic screens for Saccharomyces cerevisiae mutants with increased sensitivity to acetic acid identified loss-of-function mutations in the YPK1 gene, which encodes a protein kinase activated by the target of rapamycin (TOR) complex 2 (TORC2). We show in the present study by several independent criteria that TORC2-Ypk1 signaling is stimulated in response to acetic acid stress. Moreover, we demonstrate that TORC2-mediated Ypk1 phosphorylation and activation is necessary for acetic acid tolerance, and occurs independently of Hrk1, a protein kinase previously implicated in the cellular response to acetic acid. In addition, we show that TORC2-Ypk1-mediated activation of l-serine:palmitoyl-CoA acyltransferase, the enzyme complex that catalyzes the first committed step of sphingolipid biosynthesis, is required for acetic acid tolerance. Furthermore, analysis of the sphingolipid pathway using inhibitors and mutants indicates that it is production of certain complex sphingolipids that contributes to conferring acetic acid tolerance. Consistent with that conclusion, promoting sphingolipid synthesis by adding exogenous long-chain base precursor phytosphingosine to the growth medium enhanced acetic acid tolerance. Thus appropriate modulation of the TORC2-Ypk1-sphingolipid axis in industrial yeast strains may have utility in improving fermentations of acetic acid-containing feedstocks. © 2016 The Author(s); published by Portland Press Limited on behalf of the

  9. Adsorption characteristics of 14C-labeled alanine, aspartic acid and adenosine triphosphate by metal-chelating resins

    International Nuclear Information System (INIS)

    Ishiyama, Toshio; Matsunami, Tadao; Shibata, Setsuko; Honda, Yoshihide.

    1987-01-01

    (1) Adsorption properties of 14 C-alanine, 14 C-ATP (adenosine triphosphate) and 14 C-aspartic acid on the metal-chelating resins were determined and found that the Cu(II)-Chelex 100 and Fe(III)-Unicellex UR10, Fe(III)-Chelex 100 chelating resins were highly effective for the adsorption of 14 C-alanine and 14 C-ATP, respectively. (2) Desorption rate of 14 C-ATP from the Fe(III)-Unicellex UR10 and Fe(III)-Chelex 100 resins was somewhat higher than the case of 14 C-alanine, probably because the coordination bonds of Cu-alanine might be stronger than those of Fe-ATP. Thus, 14 C-labeled organic compounds such as 14 C-alanine and 14 C-ATP of a low activity concentration (3.7 mBq/ml) (1 x 10 -7 μCi/ml) in aqueous solution may be measured with liquid scintillation counter after pre-concentration by use of the Fe(III)- and Cu(II)-chelating resin columns. (author)

  10. 6-Methyl-1,2,4-benzenetriol, a new intermediate in penicillic acid biosynthesis in Penicillium cyclopium

    International Nuclear Information System (INIS)

    Sekiguchi, J.; Katayama, S.; Yamada, Y.

    1987-01-01

    Penicillic acid-negative mutants were obtained from a color mutant derived from Penicillium cyclopium NRRL 1888 through N-methyl-N'-nitro-N-nitrosoguanidine treatment. One mutant (SK2N6) accumulated 6-methyl-1,2,4-benzenetriol, which was not previously known to be a metabolite of P. cyclopium, in addition to orsellinic acid and orcinol. The radioactivity of [1- 14 C]acetic acid was rapidly incorporated into 6-methyl-1,2,4-benzenetriol in a culture of P. cyclopium SK2N6. Moreover, the radioactivity of [ 14 C]6-methyl-1,2,4-benzenetriol was efficiently incorporated into penicillic acid in a culture of P. cyclopium NRRL 1888. These data indicate that 6-methyl-1,2,4-benzenetriol is a precursor for penicillic acid biosynthesis. The results on the addition of 1,4-dihydroxy-6-methoxy-2-methylbenzene, 6-methoxy-2-methylbenzoquinone (1,4), and 1-O-methylorcinol to a culture of P. cyclopium SK2N6 indicated that only the former two compounds are converted to penicillic acid. Thus, a new portion of the penicillic acid biosynthetic pathway is proposed

  11. RNA Sequencing and Coexpression Analysis Reveal Key Genes Involved in α-Linolenic Acid Biosynthesis in Perilla frutescens Seed

    Directory of Open Access Journals (Sweden)

    Tianyuan Zhang

    2017-11-01

    Full Text Available Perilla frutescen is used as traditional food and medicine in East Asia. Its seeds contain high levels of α-linolenic acid (ALA, which is important for health, but is scarce in our daily meals. Previous reports on RNA-seq of perilla seed had identified fatty acid (FA and triacylglycerol (TAG synthesis genes, but the underlying mechanism of ALA biosynthesis and its regulation still need to be further explored. So we conducted Illumina RNA-sequencing in seven temporal developmental stages of perilla seeds. Sequencing generated a total of 127 million clean reads, containing 15.88 Gb of valid data. The de novo assembly of sequence reads yielded 64,156 unigenes with an average length of 777 bp. A total of 39,760 unigenes were annotated and 11,693 unigenes were found to be differentially expressed in all samples. According to Kyoto Encyclopedia of Genes and Genomes (KEGG pathway analysis, 486 unigenes were annotated in the “lipid metabolism” pathway. Of these, 150 unigenes were found to be involved in fatty acid (FA biosynthesis and triacylglycerol (TAG assembly in perilla seeds. A coexpression analysis showed that a total of 104 genes were highly coexpressed (r > 0.95. The coexpression network could be divided into two main subnetworks showing over expression in the medium or earlier and late phases, respectively. In order to identify the putative regulatory genes, a transcription factor (TF analysis was performed. This led to the identification of 45 gene families, mainly including the AP2-EREBP, bHLH, MYB, and NAC families, etc. After coexpression analysis of TFs with highly expression of FAD2 and FAD3 genes, 162 TFs were found to be significantly associated with two FAD genes (r > 0.95. Those TFs were predicted to be the key regulatory factors in ALA biosynthesis in perilla seed. The qRT-PCR analysis also verified the relevance of expression pattern between two FAD genes and partial candidate TFs. Although it has been reported that some TFs

  12. De Novo Transcriptome Analysis of Warburgia ugandensis to Identify Genes Involved in Terpenoids and Unsaturated Fatty Acids Biosynthesis.

    Science.gov (United States)

    Wang, Xin; Zhou, Chen; Yang, Xianpeng; Miao, Di; Zhang, Yansheng

    2015-01-01

    The bark of Warburgia ugandensis (Canellaceae family) has been used as a medicinal source for a long history in many African countries. The presence of diverse terpenoids and abundant polyunsaturated fatty acids (PUFAs) in this organ contributes to its broad range of pharmacological properties. Despite its medicinal and economic importance, the knowledge on the biosynthesis of terpenoid and unsaturated fatty acid in W. ugandensis bark remains largely unknown. Therefore, it is necessary to construct a genomic and/or transcriptomic database for the functional genomics study on W. ugandensis. The chemical profiles of terpenoids and fatty acids between the bark and leaves of W. ugandensis were compared by gas chromatography-mass spectrometry (GC-MS) analysis. Meanwhile, the transcriptome database derived from both tissues was created using Illumina sequencing technology. In total, about 17.1 G clean nucleotides were obtained, and de novo assembled into 72,591 unigenes, of which about 38.06% can be aligned to the NCBI non-redundant protein database. Many candidate genes in the biosynthetic pathways of terpenoids and unsaturated fatty acids were identified, including 14 unigenes for terpene synthases. Furthermore, 2,324 unigenes were discovered to be differentially expressed between both tissues; the functions of those differentially expressed genes (DEGs) were predicted by gene ontology enrichment and metabolic pathway enrichment analyses. In addition, the expression of 12 DEGs with putative roles in terpenoid and unsaturated fatty acid metabolic pathways was confirmed by qRT-PCRs, which was consistent with the data of the RNA-sequencing. In conclusion, we constructed a comprehensive transcriptome dataset derived from the bark and leaf of W. ugandensis, which forms the basis for functional genomics studies on this plant species. Particularly, the comparative analysis of the transcriptome data between the bark and leaf will provide critical clues to reveal the regulatory

  13. Biosynthesis of a linoleic acid allylic epoxide: mechanistic comparison with its chemical synthesis and leukotriene A biosynthesiss⃞

    Science.gov (United States)

    Niisuke, Katrin; Boeglin, William E.; Murray, John J.; Schneider, Claus; Brash, Alan R.

    2009-01-01

    Biosynthesis of the leukotriene A (LTA) class of epoxide is a lipoxygenase-catalyzed transformation requiring a fatty acid hydroperoxide substrate containing at least three double bonds. Here, we report on biosynthesis of a dienoic analog of LTA epoxides via a different enzymatic mechanism. Beginning with homolytic cleavage of the hydroperoxide moiety, a catalase/peroxidase-related hemoprotein from Anabaena PCC 7120, which occurs in a fusion protein with a linoleic acid 9R-lipoxygenase, dehydrates 9R-hydroperoxylinoleate to a highly unstable epoxide. Using methods we developed for isolating extremely labile compounds, we prepared and purified the epoxide and characterized its structure as 9R,10R-epoxy-octadeca-11E,13E-dienoate. This epoxide hydrolyzes to stable 9,14-diols that were reported before in linoleate autoxidation (Hamberg, M. 1983. Autoxidation of linoleic acid: Isolation and structure of four dihydroxy octadecadienoic acids. Biochim. Biophys. Acta 752: 353–356) and in incubations with the Anabaena enzyme (Lang, I., C. Göbel, A. Porzel, I. Heilmann, and I. Feussner. 2008. A lipoxygenase with linoleate diol synthase activity from Nostoc sp. PCC 7120. Biochem. J. 410: 347–357). We also prepared an equivalent epoxide from 13S-hydroperoxylinoleate using a “biomimetic” chemical method originally described for LTA4 synthesis and showed that like LTA4, the C18.2 epoxide conjugates readily with glutathione, a potential metabolic fate in vivo. We compare and contrast the mechanisms of LTA-type allylic epoxide synthesis by lipoxygenase, catalase/peroxidase, and chemical transformations. These findings provide new insights into the reactions of linoleic acid hydroperoxides and extend the known range of catalytic activities of catalase-related hemoproteins. PMID:19244216

  14. Silencing of BnTT1 family genes affects seed flavonoid biosynthesis and alters seed fatty acid composition in Brassica napus.

    Science.gov (United States)

    Lian, Jianping; Lu, Xiaochun; Yin, Nengwen; Ma, Lijuan; Lu, Jing; Liu, Xue; Li, Jiana; Lu, Jun; Lei, Bo; Wang, Rui; Chai, Yourong

    2017-01-01

    TRANSPARENT TESTA1 (TT1) is a zinc finger protein that contains a WIP domain. It plays important roles in controlling differentiation and pigmentation of the seed coat endothelium, and can affect the expression of early biosynthetic genes and late biosynthetic genes of flavonoid biosynthesis in Arabidopsis thaliana. In Brassica napus (AACC, 2n=38), the functions of BnTT1 genes remain unknown and few studies have focused on their roles in fatty acid (FA) biosynthesis. In this study, BnTT1 family genes were silenced by RNA interference, which resulted in yellow rapeseed, abnormal testa development (a much thinner testa), decreased seed weight, and altered seed FA composition in B. napus. High-throughput sequencing of genes differentially expressed between developing transgenic B. napus and wild-type seeds revealed altered expression of numerous genes involved in flavonoid and FA biosynthesis. As a consequence of this altered expression, we detected a marked decrease of oleic acid (C18:1) and notable increases of linoleic acid (C18:2) and α-linolenic acid (C18:3) in mature transgenic B. napus seeds by gas chromatography and near-infrared reflectance spectroscopy. Meanwhile, liquid chromatography-mass spectrometry showed reduced accumulation of flavonoids in transgenic seeds. Therefore, we propose that BnTT1s are involved in the regulation of flavonoid biosynthesis, and may also play a role in FA biosynthesis in B. napus. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Ornithine Decarboxylase-Mediated Production of Putrescine Influences Ganoderic Acid Biosynthesis by Regulating Reactive Oxygen Species in Ganoderma lucidum.

    Science.gov (United States)

    Wu, Chen-Gao; Tian, Jia-Long; Liu, Rui; Cao, Peng-Fei; Zhang, Tian-Jun; Ren, Ang; Shi, Liang; Zhao, Ming-Wen

    2017-10-15

    Putrescine is an important polyamine that participates in a variety of stress responses. Ornithine decarboxylase (ODC) is a key enzyme that catalyzes the biosynthesis of putrescine. A homolog of the gene encoding ODC was cloned from Ganoderma lucidum In the ODC -silenced strains, the transcript levels of the ODC gene and the putrescine content were significantly decreased. The ODC -silenced strains were more sensitive to oxidative stress. The content of ganoderic acid was increased by approximately 43 to 46% in the ODC -silenced strains. The content of ganoderic acid could be recovered after the addition of exogenous putrescine. Additionally, the content of reactive oxygen species (ROS) was significantly increased by approximately 1.3-fold in the ODC -silenced strains. The ROS content was significantly reduced after the addition of exogenous putrescine. The gene transcript levels and the activities of four major antioxidant enzymes were measured to further explore the effect of putrescine on the intracellular ROS levels. Further studies showed that the effect of the ODC-mediated production of putrescine on ROS might be a factor influencing the biosynthesis of ganoderic acid. Our study reports the role of putrescine in large basidiomycetes, providing a basis for future studies of the physiological functions of putrescine in microbes. IMPORTANCE It is well known that ODC and the ODC-mediated production of putrescine play an important role in resisting various environmental stresses, but there are few reports regarding the mechanisms underlying the effect of putrescine on secondary metabolism in microorganisms, particularly in fungi. G. lucidum is gradually becoming a model organism for studying environmental regulation and metabolism. In this study, a homolog of the gene encoding ODC was cloned in Ganoderma lucidum We found that the transcript level of the ODC gene and the content of putrescine were significantly decreased in the ODC -silenced strains. The content of

  16. Synthesis and study on biological activity of nitrogen-containing heterocyclic compounds – regulators of enzymes of nucleic acid biosynthesis

    Directory of Open Access Journals (Sweden)

    Alexeeva I. V.

    2013-07-01

    Full Text Available Results of investigations on the development of new regulators of functional activity of nucleic acid biosynthesis enzymes based on polycyclic nitrogen-containing heterosystems are summarized. Computer design and molecular docking in the catalytic site of target enzyme (T7pol allowed to perform the directed optimization of basic structures. Several series of compounds were obtained and efficient inhibitors of herpes family (simple herpes virus type 2, Epstein-Barr virus, influenza A and hepatitis C viruses were identified, as well as compounds with potent antitumor, antibacterial and antifungal activity. It was established that the use of model test systems based on enzymes participating in nucleic acids synthesis is a promising approach to the primary screening of potential inhibitors in vitro.

  17. Novel polysiloxane resin functionalized with dicyclohexano-18-crown-6 (DCH18C6): Synthesis, characterization and extraction of Sr(II) in high acidity HNO3 medium.

    Science.gov (United States)

    Ye, Gang; Bai, Feifei; Wei, Jichao; Wang, Jianchen; Chen, Jing

    2012-07-30

    A novel kind of polysiloxane resin functionalized with dicyclohexano-18-crown-6 (DCH18C6) was synthesized through a post-modification approach. The DCH18C6 moieties bearing amino groups were firstly prepared, followed by covalent grafting to a silica precursor P-(CH(2))(3)-Cl (Where P represents a 3-dimentional polymerized silica matrix) based on nucleophilic substitution reaction. (29)Si and (13)C solid-state NMR, FT-IR, XPS, TGA, ESEM and elemental analysis were employed to systematically characterize the structure, thermal property and surface morphology of the functionalized resin. The results indicated that the DCH18C6 ligands were successfully bonded to the polysiloxane resin with a satisfactory grafting degree (33.6wt.%). Due to the robust organosilica framework and the covalent immobilization of the ligands, the functionalized resin had excellent thermal stability and acid resistance. Batch experiments showed that the resin could effectively separate Sr(II) in high acidity mediums. The distribution coefficient (K(d)) of 43.6cm(3)/g could be achieved in 5.0mol/L HNO(3) solution. The influences of contact time and acidity of HNO(3) on the resin's extraction performance were examined. The reusability and the selectivity to Sr(II) over interference ions were investigated. The DCH18C6-functionalized resin might be potentially applied for the radiostrontium removal in the high level liquid waste (HLLW). Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Predicting the Viscosity of Low VOC Vinyl Ester and Fatty Acid-Based Resins

    National Research Council Canada - National Science Library

    LaScala, John J; Jeyarajasingam, Amutha; Winston, Cherise; Sand, James M; Palmese, Guiseppe R

    2005-01-01

    .... The viscosities of these resins were measured as a function of reactive diluent content and type, temperature, and vinyl ester molecular weight to determine the operating window for composite manufacture...

  19. Transcriptome Profiling of Tomato Fruit Development Reveals Transcription Factors Associated with Ascorbic Acid, Carotenoid and Flavonoid Biosynthesis

    Science.gov (United States)

    Ye, Jie; Hu, Tixu; Yang, Congmei; Li, Hanxia; Yang, Mingze; Ijaz, Raina; Ye, Zhibiao; Zhang, Yuyang

    2015-01-01

    Tomato (Solanum lycopersicum) serves as a research model for fruit development; however, while it is an important dietary source of antioxidant nutrients, the transcriptional regulation of genes that determine nutrient levels remains poorly understood. Here, the transcriptomes of fruit at seven developmental stages (7, 14, 21, 28, 35, 42 and 49 days after flowering) from two tomato cultivars (Ailsa Craig and HG6-61) were evaluated using the Illumina sequencing platform. A total of 26,397 genes, which were expressed in at least one developmental stage, were detected in the two cultivars, and the expression patterns of those genes could be divided into 20 groups using a K-mean cluster analysis. Gene Ontology term enrichment analysis indicated that genes involved in RNA regulation, secondary metabolism, hormone metabolism and cell wall metabolism were the most highly differentially expressed genes during fruit development and ripening. A co-expression analysis revealed several transcription factors whose expression patterns correlated with those of genes associated with ascorbic acid, carotenoid and flavonoid biosynthesis. This transcriptional correlation was confirmed by agroinfiltration mediated transient expression, which showed that most of the enzymatic genes in the ascorbic acid biosynthesis were regulated by the overexpression of each of the three transcription factors that were tested. The metabolic dynamics of ascorbic acid, carotenoid and flavonoid were investigated during fruit development and ripening, and some selected transcription factors showed transcriptional correlation with the accumulation of ascorbic acid, carotenoid and flavonoid. This transcriptome study provides insight into the regulatory mechanism of fruit development and presents candidate transcription factors involved in secondary metabolism. PMID:26133783

  20. [Effect of hydrofluoric acid etching time and resin bonding on the flexural strength of lithium disilicate glass ceramic].

    Science.gov (United States)

    Ren, Dong-feng; Luo, Xiao-ping

    2013-08-01

    To analyze the effect of hydrofluoric acid(HFA) etching time and resin bonding on the flexural strength of IPS e.max® Press glass ceramic, and evaluate the efficacy of resin cements to seal the cracks of the etched ceramic. Two hundred and twenty-five bars (25.0 mm×3.0 mm×2.0 mm) were made from IPS e.max® Press ingots using lost-wax, hot-pressed ceramic fabrication technology and randomly divided into five groups, forty-five each.In each group, the surfaces of ceramic bars were etched by 9.5% HFA gel for 0, 20, 40, 60 and 120 s respectively. Three specimens from each group were selected to observe the microstructure by the field emission scanning electron microscope (FE-SEM). Then each group were randomly subdivided into two subgroups (n = 20).One subgroup were coverd with a thin (approximately 0.1 mm) layer of resin cement (Variolink N), whereas the other subgroup remained unaltered.Half of the specimens were stored in 37°C water bath for 24 h and the other half went through thermocycle 10 000 times before 3-point bending test to determine their flexural strength.Interfaces between resin cement and etched ceramic were examined with FE-SEM. FE-SEM results showed that etching with HFA resulted in preferential dissolution of glass ceramic, and partially supported crystals within the glass matrix were lost with the increasing of etching time.FE-SEM indicated that resin cement sealed the cracks and defects and bonded tightly to etched ceramic surface. The mean flexural strength values of group 0, 20, 40, 60 and 120 s were (384 ± 33), (347 ± 43), (330 ± 53), (327 ± 67) , and (317 ± 41) MPa respectively. The mean flexural strength of each group except group 0 s increased significantly to (420 ± 31), (435 ± 50), (400 ± 39), and (412 ± 58) MPa respectively after the application of resin cement. Overtime HFA etching could have a wakening effect on IPS e.max® Press glass-ceramic. The application of dual-curing resin cement can compensate the strength loss of

  1. Induction of the PDH bypass and upregulation of the ALDH7B4 in plants treated with herbicides inhibiting amino acid biosynthesis.

    Science.gov (United States)

    Gil-Monreal, Miriam; Zabalza, Ana; Missihoun, Tagnon D; Dörmann, Peter; Bartels, Dorothea; Royuela, Mercedes

    2017-11-01

    Imazamox and glyphosate represent two classes of herbicides that inhibit the activity of acetohydroxyacid synthase in the branched-chain amino acid biosynthesis pathway and the activity of 5-enolpyruvylshikimate-3-phosphate synthase in the aromatic amino acid biosynthesis pathway, respectively. However, it is still unclear how imazamox and glyphosate lead to plant death. Both herbicides inhibit amino-acid biosynthesis and were found to induce ethanol fermentation in plants, but an Arabidopsis mutant deficient in alcohol dehydrogenase 1 was neither more susceptible nor more resistant than the wild-type to the herbicides. In this study, we investigated the effects of the amino acid biosynthesis inhibitors, imazamox and glyphosate, on the pyruvate dehydrogenase bypass reaction and fatty acid metabolism in A. thaliana. We found that the pyruvate dehydrogenase bypass was upregulated following the treatment by the two herbicides. Our results suggest that the Arabidopsis aldehyde dehydrogenase 7B4 gene might be participating in the pyruvate dehydrogenase bypass reaction. We evaluated the potential role of the aldehyde dehydrogenase 7B4 upon herbicide treatment in the plant defence mechanism. Plants that overexpressed the ALDH7B4 gene accumulated less soluble sugars, starch, and fatty acids and grew better than the wild-type after herbicide treatment. We discuss how the upregulation of the ALDH7B4 alleviates the effects of the herbicides, potentially through the detoxification of the metabolites produced in the pyruvate dehydrogenase bypass. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Highly expressed amino acid biosynthesis genes revealed by global gene expression analysis of Salmonella enterica serovar Enteritidis during growth in whole egg are not essential for this growth

    DEFF Research Database (Denmark)

    Jakociune, Dziuginta; Herrero-Fresno, Ana; Jelsbak, Lotte

    2016-01-01

    , di/oligopeptide transport system, biotin synthesis, ferrous iron transport system, and type III secretion system. Significant downregulation of 15 genes related to formate hydrogenlyase (FHL) and trehalose metabolism was observed. The results suggested that S. Enteritidis is starved for amino......-acids, biotin and iron when growing in egg. However, site specific mutation of amino acid biosynthesis genes asnA (17.3 fold upregulated), asnB (18.6 fold upregulated), asnA/asnB and, serA (12.0 fold upregulated) and gdhA (3.7 fold upregulated), did not result in growth attenuation, suggesting that biosynthesis...

  3. Adsorption and removal of clofibric acid and diclofenac from water with MIEX resin.

    Science.gov (United States)

    Lu, Xian; Shao, Yisheng; Gao, Naiyun; Chen, Juxiang; Zhang, Yansen; Wang, Qiongfang; Lu, Yuqi

    2016-10-01

    This study demonstrates the use of MIEX resin as an efficient adsorbent for the removal of clofibric acid (CA) and diclofenac (DCF). The adsorption performance of CA and DCF are investigated by a batch mode in single-component or bi-component adsorption system. Various factors influencing the adsorption of CA and DCF, including initial concentration, contact time, adsorbent dosage, initial solution pH, agitation speed, natural organic matter and coexistent anions are studied. The Langmuir model can well describe CA adsorption in single-component system, while the Freundlich model gives better fitting in bi-component system. The DCF adsorption can be well fitted by the Freundlich model in both systems. Thermodynamic analyses show that the adsorption of CA and DCF is an endothermic (ΔH(o) > 0), entropy driven (ΔS(o) > 0) process and more randomness exists in the DCF adsorption process. The values of Gibbs free energy (ΔG(o)  0) for CA adsorption. The kinetic data suggest the adsorption of CA and DCF follow the pseudo-first-order model in both systems and the intra-particle is not the unique rate-limiting step. The adsorption process is controlled simultaneously by external mass transfer and surface diffusion according to the surface diffusion modified Biot number (Bis) ranging from 1.06 to 26.15. Moreover, the possible removal mechanism for CA and DCF is respectively proposed based on the ion exchange stoichiometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Inhibition of Streptococcus mutans biofilm formation on composite resins containing ursolic acid

    Science.gov (United States)

    Kim, Soohyeon; Song, Minju; Roh, Byoung-Duck; Park, Sung-Ho

    2013-01-01

    Objectives To evaluate the inhibitory effect of ursolic acid (UA)-containing composites on Streptococcus mutans (S. mutans) biofilm. Materials and Methods Composite resins with five different concentrations (0.04, 0.1, 0.2, 0.5, and 1.0 wt%) of UA (U6753, Sigma Aldrich) were prepared, and their flexural strengths were measured according to ISO 4049. To evaluate the effect of carbohydrate source on biofilm formation, either glucose or sucrose was used as a nutrient source, and to investigate the effect of saliva treatment, the specimen were treated with either unstimulated whole saliva or phosphate-buffered saline (PBS). For biofilm assay, composite disks were transferred to S. mutans suspension and incubated for 24 hr. Afterwards, the specimens were rinsed with PBS and sonicated. The colony forming units (CFU) of the disrupted biofilm cultures were enumerated. For growth inhibition test, the composites were placed on a polystyrene well cluster, and S. mutans suspension was inoculated. The optical density at 600 nm (OD600) was recorded by Infinite F200 pro apparatus (TECAN). One-way ANOVA and two-way ANOVA followed by Bonferroni correction were used for the data analyses. Results The flexural strength values did not show significant difference at any concentration (p > 0.01). In biofilm assay, the CFU score decreased as the concentration of UA increased. The influence of saliva pretreatment was conflicting. The sucrose groups exhibited higher CFU score than glucose group (p composite showed inhibitory effect on S. mutans biofilm formation and growth. PMID:23741708

  5. In vivo and in vitro evaluation of the efficacy of a peracetic acid-based disinfectant for decontamination of acrylic resins.

    Science.gov (United States)

    Chassot, Ana Lúcia Campani; Poisl, Maria Inês Pereira; Samuel, Susana Maria Werner

    2006-01-01

    The purpose of this study was to assess the antimicrobial efficacy of a peracetic acid-based disinfectant for decontamination of heat-polymerized, chemically activated and microwave-polymerized acrylic resins. Resin plates were contaminated in vivo upon intraoral use by 10 volunteers for 7 nights and slabs were contaminated in vitro by contact with Bacillus subtilis and Bacillus stearothermophilus. The contaminated acrylic resin specimens were immersed in a 0.2% peracetic acid-based disinfectant (Sterilife; Lifemed) for 5 min or 10 min and placed in a BHI culture medium. After incubation at 37 degrees C for 48 h, bacterial growth was assessed by analyzing turbidity of the medium. For all types of acrylic resin, no turbidity of the medium was observed for any of the resin specimens immersed in the peracetic acid-based disinfectant for either 5 or 10 min. On the other hand, the media with specimens that were not immersed in the disinfectant (control) showed turbidity in 100% of the cases, indicating the presence of microorganisms in both tested conditions. In conclusion, immersion for at least 5 min in a 0.2% peracetic acid-based disinfectant promoted high-level disinfection of heat-polymerized, chemically activated and microwave-polymerized acrylic resins contaminated with either human saliva or Bacillus subtilis or Bacillus stearothermophilus.

  6. Neutral lipid biosynthesis in engineered Escherichia coli: jojoba oil-like wax esters and fatty acid butyl esters.

    Science.gov (United States)

    Kalscheuer, Rainer; Stöveken, Tim; Luftmann, Heinrich; Malkus, Ursula; Reichelt, Rudolf; Steinbüchel, Alexander

    2006-02-01

    Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms.

  7. Manipulation of amino acid composition in soybean seeds by the combination of deregulated tryptophan biosynthesis and storage protein deficiency.

    Science.gov (United States)

    Kita, Yoichi; Nakamoto, Yumi; Takahashi, Masakazu; Kitamura, Keisuke; Wakasa, Kyo; Ishimoto, Masao

    2010-01-01

    The ability of genetic manipulation to yield greatly increased concentrations of free amino acids (FAAs) in seeds of soybean was evaluated by introduction of a feedback-insensitive mutant enzyme of tryptophan (Trp) biosynthesis into two transformation-competent breeding lines deficient in major seed storage proteins. The storage protein-deficient lines exhibited increased accumulation of certain other seed proteins as well as of FAAs including arginine (Arg) and asparagine in mature seeds. Introduction of the gene for a feedback-insensitive mutant of an alpha subunit of rice anthranilate synthase (OASA1D) into the two high-FAA breeding lines by particle bombardment resulted in a >10-fold increase in the level of free Trp in mature seeds compared with that in nontransgenic seeds. The amount of free Trp in these transgenic seeds was similar to that in OASA1D transgenic seeds of the wild-type cultivar Jack. The composition of total amino acids in seeds of the high-FAA breeding lines remained largely unaffected by the expression of OASA1D with the exception of an increase in the total Trp content. Our results therefore indicate that the extra nitrogen resource originating from storage protein deficiency was used exclusively for the synthesis of inherent alternative nitrogen reservoirs such as free Arg and not for deregulated Trp biosynthesis conferred by OASA1D. The intrinsic null mutations responsible for storage protein deficiency and the OASA1D transgene affecting Trp content were thus successfully combined and showed additive effects on the amino acid composition of soybean seeds.

  8. Selected resin acids in effluent and receiving waters derived from a bleached and unbleached kraft pulp and paper mill

    Science.gov (United States)

    Quinn, B.P.; Booth, M.M.; Delfino, J.J.; Holm, S.E.; Gross, T.S.

    2003-01-01

    Water samples were collected on three dates at 24 sites influenced by effluent from Georgia-Pacific's Palatka Pulp and Paper Mill Operation, a bleached and unbleached kraft mill near Palatka, Florida, USA. The sampling sites were located within the mill retention ponds, Rice Creek, and the St. John's River. Samples were analyzed by gas chromatography-mass spectrometry for abietic, dehydroabietic, and isopimaric acids, all of which are potentially toxic by-products of pulp production. Isopimaric acid concentrations greater than 12 mg/L were measured at the mill's effluent outfall but were less than 20 ??g/L at the end of Rice Creek. This result indicates that the waters of Rice Creek provide dilution or conditions conducive for degradation or sorption of these compounds. Large differences in resin acid concentrations were observed between sampling events. In two sampling events, the maximum observed concentrations were less than 2 mg/L for each analyte. In a third sampling event, all of the compounds were detected at concentrations greater than 10 mg/L. Data from the three sample dates showed that resin acid concentrations were below 20 ??g/L before the confluence of Rice Creek and the St. John's River in all cases.

  9. Regulation of the cholesterol biosynthetic pathway and its integration with fatty acid biosynthesis in the oleaginous microalga Nannochloropsis oceanica

    Science.gov (United States)

    2014-01-01

    Background Sterols are vital structural and regulatory components in eukaryotic cells; however, their biosynthetic pathways and functional roles in microalgae remain poorly understood. Results In the oleaginous microalga Nannochloropsis oceanica, the sterol biosynthetic pathway produces phytosterols as minor products and cholesterol as the major product. The evidence together with their deduced biosynthetic pathways suggests that N. oceanica exhibits features of both higher plants and mammals. Temporal tracking of sterol profiles and sterol-biosynthetic transcripts in response to changes in light intensity and nitrogen supply reveal that sterols play roles in cell proliferation, chloroplast differentiation, and photosynthesis. Furthermore, the dynamics of fatty acid (FA) and FA-biosynthetic transcripts upon chemical inhibitor-induced sterol depletion reveal possible co-regulation of sterol production and FA synthesis, in that the squalene epoxidase inhibitor terbinafine reduces sterol content yet significantly elevates free FA production. Thus, a feedback regulation of sterol and FA homeostasis is proposed, with the 1-deoxy-D-xylulose 5-phosphate synthase (DXS, the committed enzyme in isoprenoid and sterol biosynthesis) gene potentially subject to feedback regulation by sterols. Conclusion These findings reveal features of sterol function and biosynthesis in microalgae and suggest new genetic engineering or chemical biology approaches for enhanced oil production in microalgae. PMID:24920959

  10. Saponin biosynthesis in Saponaria vaccaria. cDNAs encoding beta-amyrin synthase and a triterpene carboxylic acid glucosyltransferase.

    Science.gov (United States)

    Meesapyodsuk, Dauenpen; Balsevich, John; Reed, Darwin W; Covello, Patrick S

    2007-02-01

    Saponaria vaccaria (Caryophyllaceae), a soapwort, known in western Canada as cowcockle, contains bioactive oleanane-type saponins similar to those found in soapbark tree (Quillaja saponaria; Rosaceae). To improve our understanding of the biosynthesis of these saponins, a combined polymerase chain reaction and expressed sequence tag approach was taken to identify the genes involved. A cDNA encoding a beta-amyrin synthase (SvBS) was isolated by reverse transcription-polymerase chain reaction and characterized by expression in yeast (Saccharomyces cerevisiae). The SvBS gene is predominantly expressed in leaves. A S. vaccaria developing seed expressed sequence tag collection was developed and used for the isolation of a full-length cDNA bearing sequence similarity to ester-forming glycosyltransferases. The gene product of the cDNA, classified as UGT74M1, was expressed in Escherichia coli, purified, and identified as a triterpene carboxylic acid glucosyltransferase. UGT74M1 is expressed in roots and leaves and appears to be involved in monodesmoside biosynthesis in S. vaccaria.

  11. Branched-chain fatty acid biosynthesis in a branched-chain amino acid aminotransferase mutant of Staphylococcus carnosus

    DEFF Research Database (Denmark)

    Beck, Hans Christian

    2005-01-01

    was observed. Despite the deficiency in IlvE activity, the mutant strain was still able to produce the short chain carboxylic acids, 3-methylbutanoic acid and 2-methylpropanoic acid when cultivated in rich medium. Supplementation experiments employing deuterated glucose induced the valine biosynthetic pathway...... the amino acids valine, isoleucine, and leucine, and required the short branched chain acids 2-methylbutanoic acid or 2-methylpropanoic acid for growth in a defined medium. The isoleucine related metabolites, alpha-keto-beta-methylvaleric acid and 2-methylbutanal also served as growth factors. Growth...... in rich medium and growth in defined medium supplemented with 2-methylpropanoic acid lead to extensive alteration of the fatty acid composition in the cell membrane. In rich medium, a change from 51.7% to 17.1% anteiso-C15:0, and from 3.6% to 33.9% iso-C14:0 fatty acids as compared to the wild-type strain...

  12. Intracellular salicylic acid is involved in signal cascade regulating low ammonium-induced taxoid biosynthesis in suspension cultures of Taxus chinensis.

    Science.gov (United States)

    Zhou, Xin; Zhong, Jian-Jiang

    2011-05-01

    It was previously reported that low initial ammonium (2 mM) in medium had significant stimulating effects on the biosynthesis of taxuyunnanine C (Tc) by Taxus chinensis cells. However, the secondary metabolism induction mechanism of the low initial ammonium is yet unknown in plant cells. To provide an insight into the defense signals response to the low initial ammonium, oxidative burst and intracellular salicylic acid (SA) were detected, and their influences on the expression of important genes in taxoid biosynthetic pathway were examined in the cell cultures of T. chinensis. Induced H(2)O(2) production, elevated phenylalanine ammonia-lyase (PAL) activity, and enhanced SA biosynthesis were observed. Interestingly, inhibition of SA biosynthesis by paclobutrazol and (BOC-aminooxy) acetic acid significantly depressed the Tc stimulation and up-regulation of Tc biosynthetic genes of geranylgeranyl diphosphate synthase and taxadiene synthase. The role of intracellular SA in regulating Tc biosynthesis was further confirmed by applying exogenous SA in normal ammonium (20 mM) medium. The results indicated that SA acted as a signal in low initial ammonium-induced Tc biosynthesis. A signal transduction cascade from defense signal response to activated transcription of taxoid biosynthetic genes and enhanced Tc production is proposed.

  13. In vivo studies of the biosynthesis of alpha-eleostearic acid in the seed of Momordica charantia L

    International Nuclear Information System (INIS)

    Liu, L.; Hammond, E.G.; Nikolau, B.J.

    1997-01-01

    In vivo radiotracer experiments using 14C-labeled acetate, oleate, linoleate, and linolenate were conducted to investigate the biosynthesis of alpha-eleostearic acid in the seeds of Momordica charantia. With the exception of [14C]linolenate, all of these precursors radioactively labeled alpha-eleostearate. Kinetics of the time course of metabolism of the radioactive precursors indicate that linoleate is the acyl precursor of alpha-eleostearate and that its conversion to alpha-eleostearate occurs while the acyl moiety is esterified to PC. Pulse-chase experiments with 14C-labeled acetate or linoleate provided additional corroborative evidence that linoleoyl PC is the precursor of alpha-eleostearoyl PC

  14. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid W

    Energy Technology Data Exchange (ETDEWEB)

    Messing, S.; Gabelli, S; Echeverria, I; Vogel, J; Guan, J; Tan, B; Klee, H; McCarty, D; Amzela, M

    2010-01-01

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  15. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Messing, Simon A.J.; Gabelli, Sandra B.; Echeverria, Ignacia; Vogel, Jonathan T.; Guan, Jiahn Chou; Tan, Bao Cai; Klee, Harry J.; McCarty, Donald R.; Amzel, L. Mario (JHU); (Florida)

    2011-09-06

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  16. Identification of microRNAs actively involved in fatty acid biosynthesis in developing Brassica napus seeds using high-throughput sequencing

    Directory of Open Access Journals (Sweden)

    Jia Wang

    2016-10-01

    Full Text Available Seed development has a critical role during the spermatophyte life cycle. In Brassica napus, a major oil crop, fatty acids are synthesized and stored in specific tissues during embryogenesis, and understanding the molecular mechanism underlying fatty acid biosynthesis during seed development is an important research goal. In this study, we constructed three small RNA libraries from early seeds at 14, 21 and 28 days after flowering (DAF and used high-throughput sequencing to examine microRNA (miRNA expression. A total of 85 known miRNAs from 30 families and 1,160 novel miRNAs were identified, of which 24, including 5 known and 19 novel miRNAs, were found to be involved in fatty acid biosynthesis. bna-miR156b, bna-miR156c, bna-miR156g, novel_mir_1706, novel_mir_1407, novel_mir_173, and novel_mir_104 were significantly down-regulated at 21 DAF and 28 DAF, whereas bna-miR159, novel_mir_1081, novel_mir_19 and novel_mir_555 were significantly up-regulated. In addition, we found that some miRNAs regulate functional genes that are directly involved in fatty acid biosynthesis and that other miRNAs regulate the process of fatty acid biosynthesis by acting on a large number of transcription factors. The miRNAs and their corresponding predicted targets were partially validated by quantitative RT-PCR. Our data suggest that diverse and complex miRNAs are involved in the seed development process and that miRNAs play important roles in fatty acid biosynthesis during seed development.

  17. Effects of the peracetic acid and sodium hypochlorite on the colour stability and surface roughness of the denture base acrylic resins polymerised by microwave and water bath methods.

    Science.gov (United States)

    Fernandes, Flavio H C N; Orsi, Iara A; Villabona, Camilo A

    2013-03-01

    This study evaluated the surface roughness (Ra) and color stability of acrylic resin colors (Lucitone 550, QC-20 and Vipi-Wave) used for fabricating bases for complete, removable dentures, overdentures and prosthetic protocol after immersion in chemical disinfectants (1% sodium hypochlorite and 2% peracetic acid) for 30 and 60 minutes. Sixty specimens were made of each commercial brand of resin composite, and divided into 2 groups according to the chemical disinfectants. Specimens had undergone the finishing and polishing procedures, the initial color and roughness measurements were taken (t=0), and after this, ten test specimens of each commercial brand of resin composite were immersed in sodium hypochlorite and ten in peracetic acid, for 30 and 60 minutes, with measurements being taken after each immersion period. These data were submitted to statistical analysis. There was evidence of an increase in Ra after 30 minutes immersion in the disinfectants in all the resins, with QC-20 presenting the highest Ra values, and Vipi-Wave the lowest. After 60 minutes immersion in the disinfectants all the resins presented statistically significant color alteration. Disinfection with 1% sodium hypochlorite and peracetic acid altered the properties of roughness and color of the resins. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

  18. The mitogen-activated protein kinase GlSlt2 regulates fungal growth, fruiting body development, cell wall integrity, oxidative stress and ganoderic acid biosynthesis in Ganoderma lucidum.

    Science.gov (United States)

    Zhang, Guang; Sun, Zehua; Ren, Ang; Shi, Liang; Shi, Dengke; Li, Xiongbiao; Zhao, Mingwen

    2017-07-01

    The mitogen-activated protein kinases (MAPKs) are crucial signaling instruments in eukaryotes that play key roles in regulating fungal growth, development, and secondary metabolism and in adapting to the environment. In this study, we characterized an Slt2-type MAPK in Ganoderma lucidum, GlSlt2, which was transcriptionally induced during the primordium and fruiting body stages. RNA interference was used to examine the function of GlSlt2. Knockdown of GlSlt2 caused defects in growth and increased hyphal branching as well as hypersensitivity to cell wall-disturbing substances. Consistently, the chitin and β-1,3-d-glucan contents and the expression of cell wall biosynthesis genes were decreased and down-regulated, respectively, in GlSlt2 knockdown strains compared with those in the wild type (WT). In addition, no primordium or fruiting body could be observed in GlSlt2 knockdown strains. Furthermore, the intracellular reactive oxygen species (ROS) content and ganoderic acid biosynthesis also decreased in GlSlt2 knockdown strains. Addition of H 2 O 2 could recover the decreased ganoderic acid content in GlSlt2 knockdown strains, indicating that GlSlt2 might regulate ganoderic acid biosynthesis via the intracellular ROS level. Overall, GlSlt2 is involved in hyphal growth, fruiting body development, cell wall integrity, oxidative stress and ganoderic acid biosynthesis in G. lucidum. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. The bile acid-sequestering resin sevelamer eliminates the acute GLP-1 stimulatory effect of endogenously released bile acids in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Brønden, Andreas; Albér, Anders; Rohde, Ulrich

    2018-01-01

    of the present study was to assess the GLP-1 secretory and gluco-metabolic effects of endogenously released bile, with and without concomitant administration of the bile acid-sequestering resin, sevelamer, in patients with type 2 diabetes. MATERIALS AND METHODS: We performed a randomized, placebo......-controlled, and double-blinded cross-over study including 15 metformin-treated patients with type 2 diabetes. Four experimental study days in randomized order with administration of either sevelamer 3,200 mg or placebo in combination with intravenous infusion of cholecystokinin (CCK) (0.4 pmol sulfated CCK-8/kg...... was shown to eliminate the acute bile acid-induced increase in plasma GLP-1 excursions. CONCLUSIONS: Single-dose administration of sevelamer eliminated bile acid-mediated GLP-1 secretion in patients with type 2 diabetes, which could be explained by reduced bile acid stimulation of the basolaterally...

  20. Changes in volatile terpene and diterpene resin acid composition of resistant and susceptible white spruce leaders exposed to simulated white pine weevil damage.

    Science.gov (United States)

    Tomlin, E S; Antonejevic, E; Alfaro, R I; Borden, J H

    2000-10-01

    Induced (traumatic) resin in white spruce (Picea glauca (Moench) Voss) leaders resistant or susceptible to the white pine weevil (Pissodes strobi Peck) was analyzed for volatile terpenes and diterpene resin acids after simulated white pine weevil damage. Leaders from 331 trees were wounded just below the apical bud with a 1-mm diameter drill, coinciding with the natural time of weevil oviposition in the spring. Leaders were removed in the fall, and the bark and xylem from the upper and lower regions of the leader extracted and analyzed by gas chromatography. Unwounded trees had low amounts of resin in xylem compared with bark. In response to wounding, volatile terpenes and diterpene resin acids increased in the upper xylem (area of wounding), with resistant trees showing a greater increase than susceptible trees. Wounding caused monoterpenes in particular to decrease in the lower region of the leader (away from the drilled area) in greater amounts in susceptible trees than in resistant trees. In response to wounding, the proportion of monoterpene to resin acid increased in the upper and lower xylem of resistant trees, and slightly increased in the upper xylem of susceptible trees. Monoterpene-enriched resin is more fluid than constitutive resin, and probably flows more readily into oviposition cavities and larval mines, where it may kill immature weevils. Loss of resin components in the lower xylem suggested catabolism and transport of these materials to the site of wounding; however, energetic and regulatory data are necessary to confirm this hypothesis. This study provides a basis for measuring the ability of a tree to undergo traumatic resinosis that could be used to screen for resistance to white pine weevil.

  1. Characterization of the Asiatic Acid Glucosyltransferase, UGT73AH1, Involved in Asiaticoside Biosynthesis in Centella asiatica (L.) Urban

    Science.gov (United States)

    Jin, Mei Lan; Jetter, Reinhard

    2017-01-01

    Centella asiatica (L.) Urban contains two ursane-type triterpene saponins, asiaticoside and madecassoside, as major secondary metabolites. In order to select candidate genes encoding UDP-glucosyltransferases (UGTs) involved in asiaticoside biosynthesis, we performed transcriptomic analysis of leaves elicited by methyl jasmonate (MeJA). Among the unigenes, 120 isotigs and 13 singletons of unique sequences were annotated as UGTs, including 37 putative full-length cDNAs, and 15 of the putative UGT genes were named according to the UGT committee nomenclature protocols. One of them, UGT73AH1, was characterized by heterologous expression in Escherichia coli BL21 (DE3) cells. After induction with IPTG, a total protein extract was assayed with UDP-glucose and asiatic acid. UPLC-QTOF/MS analysis showed that UGT73AH1 catalyzes the glycosylation of asiatic acid to its monoglucoside. It remains unclear whether glycosylation occurs on the triterpene C-2α, C-3β, C-23, or C-28 position. However, it is very likely that UGT73AH1 glucosylates the C-28 position, because only C-28 bears a glucose moiety in the final pathway product of asiatic acid, while C-2α, C-3β, and C-23 remain un-conjugated. PMID:29210992

  2. Biosynthesis of poly(4-hydroxybutyrate) in recombinant Escherichia coli grown on glycerol is stimulated by propionic acid.

    Science.gov (United States)

    Kämpf, Michael M; Thöny-Meyer, Linda; Ren, Qun

    2014-11-01

    One of the most promising polyhydroxyalkanoates (PHAs) for medical applications is poly(4-hydroxybutyrate) (P4HB) due to its biodegradability, biocompatibility and mechanical properties. Currently, the major hurdle for expanding P4HB applications is the production and recovery cost. In this study, we investigated the stimulating factors for P4HB biosynthesis with the ultimate goal of reducing production cost. We found that addition of propionic acid to the culture medium stimulates the P4HB accumulation in recombinant Escherichia coli JM109 grown on glycerol. This stimulating effect was significantly weakened by addition of exogenous methionine, whereas it was not influenced by addition of cysteine. These results suggest that propionic acid enhances P4HB synthesis by reducing the intracellular methionine pool. Utilizing these findings for P4HB production in batch cultures on glycerol, the volumetric yield of P4HB could be improved 4 fold from 0.9g/L to 3.7g/L by adding 2g/L propionic acid into the medium. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Conifer Diterpene Resin Acids Disrupt Juvenile Hormone-Mediated Endocrine Regulation in the Indian Meal Moth Plodia interpunctella.

    Science.gov (United States)

    Oh, Hyun-Woo; Yun, Chan-Seok; Jeon, Jun Hyoung; Kim, Ji-Ae; Park, Doo-Sang; Ryu, Hyung Won; Oh, Sei-Ryang; Song, Hyuk-Hwan; Shin, Yunhee; Jung, Chan Sik; Shin, Sang Woon

    2017-07-01

    Diterpene resin acids (DRAs) are important components of oleoresin and greatly contribute to the defense strategies of conifers against herbivorous insects. In the present study, we determined that DRAs function as insect juvenile hormone (JH) antagonists that interfere with the juvenile hormone-mediated binding of the JH receptor Methoprene-tolerant (Met) and steroid receptor coactivator (SRC). Using a yeast two-hybrid system transformed with Met and SRC from the Indian meal moth Plodia interpunctella, we tested the interfering activity of 3704 plant extracts against JH III-mediated Met-SRC binding. Plant extracts from conifers, especially members of the Pinaceae, exhibited strong interfering activity, and four active interfering DRAs (7α-dehydroabietic acid, 7-oxodehydroabietic acid, dehydroabietic acid, and sandaracopimaric acid) were isolated from roots of the Japanese pine Pinus densiflora. The four isolated DRAs, along with abietic acid, disrupted the juvenile hormone-mediated binding of P. interpunctella Met and SRC, although only 7-oxodehydroabietic acid disrupted larval development. These results demonstrate that DRAs may play a defensive role against herbivorous insects via insect endocrine-disrupting activity.

  4. Supplementation of linoleic acid (C18:2n-6) or α-linolenic acid (C18:3n-3) changes microbial agonist-induced oxylipid biosynthesis.

    Science.gov (United States)

    Ryman, V E; Packiriswamy, N; Norby, B; Schmidt, S E; Lock, A L; Sordillo, L M

    2017-03-01

    Oxylipids are derived from polyunsaturated fatty acids (PUFA) in cellular membranes and the relative abundance or balance may contribute to disease pathogenesis. Previous studies documented unique oxylipid profiles from cows with either coliform or Streptococcus uberis mastitis, suggesting that lipid mediator biosynthesis may be dependent on the type of microbial-derived agonist. Changing the fatty acid content of peripheral blood leukocytes also may be critical to the relative expression of oxylipid profiles and the outcome of bacterial infection. No information is available in dairy cows describing how changing cellular PUFA content will modify oxylipids in the context of a microbial agonist challenge. Therefore, the hypothesis for the current study was that PUFA supplementation would change bovine leukocyte fatty acid content and respective oxylipid profiles from ex vivo microbial agonist-challenged leukocytes. Fatty acid content of leukocytes and plasma was quantified in (1) samples from cows not supplemented with PUFA, (2) cows supplemented with linoleic acid (LnA), and (3) cows supplemented with α-linolenic acid (ALA). Plasma oxylipids were assessed after S. uberis or lipopolysaccharide exposure and was compared with unstimulated oxylipid profiles. Fatty acid supplementation with ALA significantly increased ALA content of blood leukocytes and plasma relative to LnA. Fatty acid supplementation affected several S. uberis-induced oxylipids, but only S. uberis-induced 15-oxoETE was greater with ALA supplementation compared with LnA. Notably, only LPS-induced 5,6 LXA 4 was altered with fatty acid supplementation, but no significant effect of LnA vs. ALA treatment was identified. Future studies are needed to understand how leukocyte activation and membrane PUFA availability collectively contribute to differential oxylipid profiles. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  5. Metabolism of polyunsaturated (n-3) fatty acids by monkey seminal vesicles: isolation and biosynthesis of omega-3 epoxides.

    Science.gov (United States)

    Oliw, E H; Sprecher, H W

    1991-11-27

    Monooxygenases of monkey seminal vesicles can metabolize arachidonic acid (20:4(n-6)) by w3-hydroxylation to 18(R)-hydroxyeicosatetraenoic acid (18(R)-HETE) and eicosapentaenoic acid (20:5(n-3)) to 17,18-dihydroxyeicosatetraenoic acid (Oliw, E.H. (1989) J. Biol. Chem. 264, 17845-17853). The present study aimed to further characterize the oxygenation of (n-3) polyunsaturated fatty acids. 14C-Labelled 22:6(n-3), 20:5(n-3), 20:4-(n-3) and 18:3(n-3) were incubated with microsomes of seminal vesicles of the cynomolgus monkey, NADPH and a cyclooxygenase inhibitor, diclofenac, and the main metabolites were identified by capillary gas chromatography-mass spectrometry. 22:6(n-3) was slowly metabolized to 19,20-dihydroxy-4,7,10,13,16-docosapentaenoic acid, while 20:5(n-3), 20:4(n-3) and 18:3(n-3) were metabolized more efficiently to the corresponding w4,w3-diols. The w3 epoxides, which were obtained from 20:5(n-3) and 18:3(n-3), were isolated in the presence of an epoxide hydrolase inhibitor, 1(2)epoxy-3,3,3-trichloropropane, and the geometry of the epoxides was determined to be 17S, 18R and 15S, 16R, respectively. While 20:5(n-3) was metabolized almost exclusively to the epoxide and diol pair of metabolites, 18:3(n-3) was metabolized not only to the w3 epoxide and the corresponding diol, but also to the w2 alcohol, 17(R)-hydroxy-9,12,15-octadecatrienoic acid. 22:6(n-3) and 5,8,11,14-eicosatetraynoic acid inhibited the biosynthesis of 18(R)-HETE from arachidonic acid (IC50 0.16 and 0.14 mM, respectively). In comparison with 20:4 or 18:3(n-3), 18:1(n-9) and 22:5(n-6) appeared to be slowly metabolized by seminal monooxygenases, while 18:2(n-6) was converted to the w3 alcohol and to smaller amounts of the w2 alcohol (4:1). Together, the results indicate that the w3-hydroxylase and w3-epoxygenase enzyme(s) metabolize 20:4(n-6) and 20:5(n-3) almost exclusively to the w3(R) alcohol and the w3(R, S) epoxide, respectively, while longer and shorter fatty acids either are poor

  6. Further Studies on Oxalic Acid Biosynthesis in Oxalate-accumulating Plants 1

    Science.gov (United States)

    Nuss, Richard F.; Loewus, Frank A.

    1978-01-01

    l-Ascorbic acid functions as a precursor of oxalic acid in several oxalate-accumulating plants. The present study extends this observation to include Rumex crispus L. (curly dock), Amaranthus retroflexus L. (red root pigweed), Chenopodium album L. (lamb's-quarters), Beta vulgaris L. (sugar beet), Halogeton glomeratus M. Bieb. (halogeton), and Rheum rhabarbarum L. (rhubarb). Several species with low oxalate content are also examined. When l-[1-14C]ascorbic acid is supplied to young seedlings of R. crispus or H. glomeratus, a major portion of the 14C is released over a 24-hour period as 14CO2 and only a small portion is recovered as [14C]oxalate, unlike cuttings from 2- or 4-month-old plants which retain a large part of the 14C as [14C]oxalic acid and release very little 14CO2. Support for an intermediate role of oxalate in the release of 14CO2 from l-[1-14C]ascorbic acid is seen in the rapid release of 14CO2 by R. crispus and H. glomeratus seedlings labeled with [14C]oxalic acid. The common origin of oxalic acid carbon in the C1 and C2 fragment from l-ascorbic acid is demonstrated by comparison of 14C content of oxalic acid in several oxalate-accumulators after cuttings or seedlings are supplied equal amounts of l-[1-14C]- or l-[UL-14C]ascorbic acid. Theoretically, l-[1-14C]ascorbic acid will produce labeled oxalic acid containing three times as much 14C as l-[UL-14C]ascorbic acid when equal amounts of label are provided. Experimentally, a ratio of 2.7 ± 0.5 is obtained in duplicate experiments with six different species. PMID:16660342

  7. Further Studies on Oxalic Acid Biosynthesis in Oxalate-accumulating Plants.

    Science.gov (United States)

    Nuss, R F; Loewus, F A

    1978-04-01

    l-Ascorbic acid functions as a precursor of oxalic acid in several oxalate-accumulating plants. The present study extends this observation to include Rumex crispus L. (curly dock), Amaranthus retroflexus L. (red root pigweed), Chenopodium album L. (lamb's-quarters), Beta vulgaris L. (sugar beet), Halogeton glomeratus M. Bieb. (halogeton), and Rheum rhabarbarum L. (rhubarb). Several species with low oxalate content are also examined.When l-[1-(14)C]ascorbic acid is supplied to young seedlings of R. crispus or H. glomeratus, a major portion of the (14)C is released over a 24-hour period as (14)CO(2) and only a small portion is recovered as [(14)C]oxalate, unlike cuttings from 2- or 4-month-old plants which retain a large part of the (14)C as [(14)C]oxalic acid and release very little (14)CO(2). Support for an intermediate role of oxalate in the release of (14)CO(2) from l-[1-(14)C]ascorbic acid is seen in the rapid release of (14)CO(2) by R. crispus and H. glomeratus seedlings labeled with [(14)C]oxalic acid.The common origin of oxalic acid carbon in the C1 and C2 fragment from l-ascorbic acid is demonstrated by comparison of (14)C content of oxalic acid in several oxalate-accumulators after cuttings or seedlings are supplied equal amounts of l-[1-(14)C]- or l-[UL-(14)C]ascorbic acid. Theoretically, l-[1-(14)C]ascorbic acid will produce labeled oxalic acid containing three times as much (14)C as l-[UL-(14)C]ascorbic acid when equal amounts of label are provided. Experimentally, a ratio of 2.7 +/- 0.5 is obtained in duplicate experiments with six different species.

  8. Synthetic resin-bound truncated Candida antarctica lipase B for production of fatty acid alkyl esters by transesterification of corn and soybean oils with ethanol or butanol.

    Science.gov (United States)

    Hughes, Stephen R; Moser, Bryan R; Robinson, Samantha; Cox, Elby J; Harmsen, Amanda J; Friesen, Jon A; Bischoff, Kenneth M; Jones, Marjorie A; Pinkelman, Rebecca; Bang, Sookie S; Tasaki, Ken; Doll, Kenneth M; Qureshi, Nasib; Liu, Siqing; Saha, Badal C; Jackson, John S; Cotta, Michael A; Rich, Joseph O; Caimi, Paolo

    2012-05-31

    A gene encoding a synthetic truncated Candida antarctica lipase B (CALB) was generated via automated PCR and expressed in Saccharomyces cerevisiae. Western blot analysis detected five truncated CALB variants, suggesting multiple translation starts from the six in-frame ATG codons. The longest open reading frame, which corresponds to amino acids 35-317 of the mature lipase, appeared to be expressed in the greatest amount. The truncated CALB was immobilized on Sepabeads® EC-EP resin and used to produce ethyl and butyl esters from crude corn oil and refined soybean oil. The yield of ethyl esters was 4-fold greater from corn oil than from soybean oil and was 36% and 50% higher, respectively, when compared to a commercially available lipase resin (Novozym 435) using the same substrates. A 5:1 (v/v) ratio of ethanol to corn oil produced 3.7-fold and 8.4-fold greater yields than ratios of 15:1 and 30:1, respectively. With corn oil, butyl ester production was 56% higher than ethyl ester production. Addition of an ionic catalytic resin step prior to the CALB resin increased yields of ethyl esters from corn oil by 53% compared to CALB resin followed by ionic resin. The results suggest resin-bound truncated CALB has potential application in biodiesel production using biocatalysts. Published by Elsevier B.V.

  9. Salicylic Acid Induction of Flavonoid Biosynthesis Pathways in Wheat Varies by Treatment.

    Science.gov (United States)

    Gondor, Orsolya K; Janda, Tibor; Soós, Vilmos; Pál, Magda; Majláth, Imre; Adak, Malay K; Balázs, Ervin; Szalai, Gabriella

    2016-01-01

    Salicylic acid is a promising compound for the reduction of stress sensitivity in plants. Although several biochemical and physiological changes have been described in plants treated with salicylic acid, the mode of action of the various treatments has not yet been clarified. The present work reports a detailed comparative study on the effects of different modes of salicylic acid application at the physiological, metabolomic, and transcriptomic levels. Seed soaking and hydroponic treatments were found to induce various changes in the protective mechanisms of wheat plants. The possible involvement of the flavonoid metabolism in salicylic acid-related stress signaling was also demonstrated. Different salicylic acid treatments were shown to induce different physiological and biochemical processes, with varying responses in the leaves and roots. Hydroponic treatment enhanced the level of oxidative stress, the expression of genes involved in the flavonoid metabolism and the amount of non-enzymatic antioxidant compounds, namely ortho-hydroxycinnamic acid and the flavonol quercetin in the leaves, while it decreased the ortho-hydroxycinnamic acid and flavonol contents and enhanced ascorbate peroxidase activity in the roots. In contrast, seed soaking only elevated the gene expression level of phenylalanine ammonia lyase in the roots and caused a slight increase in the amount of flavonols. These results draw attention to the fact that the effects of exogenous salicylic acid application cannot be generalized in different experimental systems and that the flavonoid metabolism may be an important part of the action mechanisms induced by salicylic acid.

  10. Glucose-6-phosphate dehydrogenase as a target for highly efficient fatty acid biosynthesis in microalgae by enhancing NADPH supply.

    Science.gov (United States)

    Xue, Jiao; Balamurugan, Srinivasan; Li, Da-Wei; Liu, Yu-Hong; Zeng, Hao; Wang, Lan; Yang, Wei-Dong; Liu, Jie-Sheng; Li, Hong-Ye

    2017-05-01

    Oleaginous microalgae have great prospects in the fields of feed, nutrition, biofuel, etc. However, biomass and lipid productivity in microalgae remain a major economic and technological bottleneck. Here we present a novel regulatory target, glucose-6-phosphate dehydrogenase (G6PD) from the pentose phosphate pathway (PPP), in boosting microalgal lipid accumulation. G6PD, involved in the formation of NADPH demanded in fatty acid biosynthesis as reducing power, was characterized in oleaginous microalga Phaeodactylum tricornutum. In G6PD overexpressing microalgae, transcript abundance of G6PD increased by 4.4-fold, and G6PD enzyme activity increased by more than 3.1-fold with enhanced NADPH production. Consequently, the lipid content increased by 2.7-fold and reached up to 55.7% of dry weight, while cell growth was not apparently affected. The fatty acid composition exhibited significant changes, including a remarkable increase in monounsaturated fatty acids C16:1 and C18:1 concomitant with a decrease in polyunsaturated fatty acids C20:5 and C22:6. G6PD was localized to the chloroplast and its overexpression stimulated an increase in the number and size of oil bodies. Proteomic and metabolomic analyzes revealed that G6PD play a key role in regulating pentose phosphate pathway and subsequently upregulating NADPH consuming pathways such as fatty acid synthesis, thus eventually leading to lipid accumulation. Our findings show the critical role of G6PD in microalgal lipid accumulation by enhancing NADPH supply and demonstrate that G6PD is a promising target for metabolic engineering. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  11. Ion Exchange Study of Some New Copolymer Resins Derived from 8-Hydroxyquinoline-5-sulphonic Acid, Biuret and Formaldehyde

    Directory of Open Access Journals (Sweden)

    P. A. Dhakite

    2011-01-01

    Full Text Available Copolymer resins (8-HQSABF were synthesized by the condensation of 8-hydroxyquinoline-5-sulphonic acid and biuret with formaldehyde in the presence of hydrochloric acid as catalyst, proved to be selective chelation ion exchange copolymer resins for certain metals. Chelation ion exchange properties to these polymers were studied for Cu2+, Cd2+, Co2+ and Zn2+ ions. A batch equilibrium method was employed in the study of the selectivity of the distribution of a given metal ions between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in a media of various ions strengths. The polymer showed a higher selectivity for Cu2+ ions than for Cd2+, Co2+ and Zn2+ ions. Hence on the basis of above studies these copolymer may be used as semiconductors, surface coating, ion-exchangers, materials for rechargeable battery cell in various electronic industries, plastic materials, elastomers and in boiler plants

  12. A Robust Epoxy Resins @ Stearic Acid-Mg(OH)2 Micronanosheet Superhydrophobic Omnipotent Protective Coating for Real-Life Applications.

    Science.gov (United States)

    Si, Yifan; Guo, Zhiguang; Liu, Weimin

    2016-06-29

    Superhydrophobic coating has extremely high application value and practicability. However, some difficult problems such as weak mechanical strength, the need for expensive toxic reagents, and a complex preparation process are all hard to avoid, and these problems have impeded the superhydrophobic coating's real-life application for a long time. Here, we demonstrate one kind of omnipotent epoxy resins @ stearic acid-Mg(OH)2 superhydrophobic coating via a simple antideposition route and one-step superhydrophobization process. The whole preparation process is facile, and expensive toxic reagents needed. This omnipotent coating can be applied on any solid substrate with great waterproof ability, excellent mechanical stability, and chemical durability, which can be stored in a realistic environment for more than 1 month. More significantly, this superhydrophobic coating also has four protective abilities, antifouling, anticorrosion, anti-icing, and flame-retardancy, to cope with a variety of possible extreme natural environments. Therefore, this omnipotent epoxy resins @ stearic acid-Mg(OH)2 superhydrophobic coating not only satisfies real-life need but also has great application potential in many respects.

  13. Biosynthesis of Polyunsaturated Fatty Acids in Octopus vulgaris: Molecular Cloning and Functional Characterisation of a Stearoyl-CoA Desaturase and an Elongation of Very Long-Chain Fatty Acid 4 Protein.

    Science.gov (United States)

    Monroig, Óscar; de Llanos, Rosa; Varó, Inmaculada; Hontoria, Francisco; Tocher, Douglas R; Puig, Sergi; Navarro, Juan C

    2017-03-21

    Polyunsaturated fatty acids (PUFAs) have been acknowledged as essential nutrients for cephalopods but the specific PUFAs that satisfy the physiological requirements are unknown. To expand our previous investigations on characterisation of desaturases and elongases involved in the biosynthesis of PUFAs and hence determine the dietary PUFA requirements in cephalopods, this study aimed to investigate the roles that a stearoyl-CoA desaturase (Scd) and an elongation of very long-chain fatty acid 4 (Elovl4) protein play in the biosynthesis of essential fatty acids (FAs). Our results confirmed the Octopus vulgaris Scd is a ∆9 desaturase with relatively high affinity towards saturated FAs with ≥ C 18 chain lengths. Scd was unable to desaturate 20:1 n- 15 ( ∆5 20:1) suggesting that its role in the biosynthesis of non-methylene interrupted FAs (NMI FAs) is limited to the introduction of the first unsaturation at ∆9 position. Interestingly, the previously characterised ∆5 fatty acyl desaturase was indeed able to convert 20:1 n- 9 ( ∆11 20:1) to ∆5,11 20:2, an NMI FA previously detected in octopus nephridium. Additionally, Elovl4 was able to mediate the production of 24:5 n- 3 and thus can contribute to docosahexaenoic acid (DHA) biosynthesis through the Sprecher pathway. Moreover, the octopus Elovl4 was confirmed to play a key role in the biosynthesis of very long-chain (>C 24 ) PUFAs.

  14. Transcriptional regulation of chlorogenic acid biosynthesis in carrot root slices exposed to UV-B light

    Science.gov (United States)

    Orange carrots are well known for their nutritional value as producers of ß-carotene, a Vitamin A precursor. Lesser known, is their ability to accumulate antioxidants such as chlorogenic acid. Chlorogenic acid is produced through the same biosynthetic pathway that produces lignins, anthocyanins, f...

  15. Heteroconium chaetospira induces resistance to clubroot via upregulation of host genes involved in jasmonic acid, ethylene, and auxin biosynthesis.

    Directory of Open Access Journals (Sweden)

    Rachid Lahlali

    Full Text Available An endophytic fungus, Heteroconium chaetospira isolate BC2HB1 (Hc, suppressed clubroot (Plasmodiophora brassicae -Pb on canola in growth-cabinet trials. Confocal microscopy demonstrated that Hc penetrated canola roots and colonized cortical tissues. Based on qPCR analysis, the amount of Hc DNA found in canola roots at 14 days after treatment was negatively correlated (r = 0.92, P<0.001 with the severity of clubroot at 5 weeks after treatment at a low (2×10(5 spores pot(-1 but not high (2×10(5 spores pot(-1 dose of pathogen inoculum. Transcript levels of nine B. napus (Bn genes in roots treated with Hc plus Pb, Pb alone and a nontreated control were analyzed using qPCR supplemented with biochemical analysis for the activity of phenylalanine ammonia lyases (PAL. These genes encode enzymes involved in several biosynthetic pathways related potentially to plant defence. Hc plus Pb increased the activity of PAL but not that of the other two genes (BnCCR and BnOPCL involved also in phenylpropanoid biosynthesis, relative to Pb inoculation alone. In contrast, expression of several genes involved in the jasmonic acid (BnOPR2, ethylene (BnACO, auxin (BnAAO1, and PR-2 protein (BnPR-2 biosynthesis were upregulated by 63, 48, 3, and 3 fold, respectively, by Hc plus Pb over Pb alone. This indicates that these genes may be involved in inducing resistance in canola by Hc against clubroot. The upregulation of BnAAO1 appears to be related to both pathogenesis of clubroot and induced defence mechanisms in canola roots. This is the first report on regulation of specific host genes involved in induced plant resistance by a non-mycorrhizal endophyte.

  16. Biosynthesis of platform chemical 3-hydroxypropionic acid (3-HP) directly from CO2 in cyanobacterium Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Wang, Yunpeng; Sun, Tao; Gao, Xingyan; Shi, Mengliang; Wu, Lina; Chen, Lei; Zhang, Weiwen

    2016-03-01

    3-hydroxypropionic acid (3-HP) is an important platform chemical with a wide range of applications. So far large-scale production of 3-HP has been mainly through petroleum-based chemical processes, whose sustainability and environmental issues have attracted widespread attention. With the ability to fix CO2 directly, cyanobacteria have been engineered as an autotrophic microbial cell factory to produce fuels and chemicals. In this study, we constructed the biosynthetic pathway of 3-HP in cyanobacterium Synechocystis sp. PCC 6803, and then optimized the system through the following approaches: i) increasing expression of malonyl-CoA reductase (MCR) gene using different promoters and cultivation conditions; ii) enhancing supply of the precursor malonyl-CoA by overexpressing acetyl-CoA carboxylase and biotinilase; iii) improving NADPH supply by overexpressing the NAD(P) transhydrogenase gene; iv) directing more carbon flux into 3-HP by inactivating the competing pathways of PHA and acetate biosynthesis. Together, the efforts led to a production of 837.18 mg L(-1) (348.8 mg/g dry cell weight) 3-HP directly from CO2 in Synechocystis after 6 days cultivation, demonstrating the feasibility photosynthetic production of 3-HP directly from sunlight and CO2 in cyanobacteria. In addition, the results showed that overexpression of the ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) gene from Anabaena sp. PCC 7120 and Synechococcus sp. PCC 7942 led to no increase of 3-HP production, suggesting CO2 fixation may not be a rate-limiting step for 3-HP biosynthesis in Synechocystis. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  17. Biosynthesis of the microtubule-destabilizing diterpene pseudolaric acid B from golden larch involves an unusual diterpene synthase

    Science.gov (United States)

    Mafu, Sibongile; Karunanithi, Prema Sambandaswami; Palazzo, Teresa Ann; Harrod, Bronwyn Lee; Rodriguez, Selina Marakana; Mollhoff, Iris Natalie; O’Brien, Terrence Edward; Tong, Shen; Fiehn, Oliver; Tantillo, Dean J.; Bohlmann, Jörg; Zerbe, Philipp

    2017-01-01

    The diversity of small molecules formed via plant diterpene metabolism offers a rich source of known and potentially new biopharmaceuticals. Among these, the microtubule-destabilizing activity of pseudolaric acid B (PAB) holds promise for new anticancer agents. PAB is found, perhaps uniquely, in the coniferous tree golden larch (Pseudolarix amabilis, Pxa). Here we describe the discovery and mechanistic analysis of golden larch terpene synthase 8 (PxaTPS8), an unusual diterpene synthase (diTPS) that catalyzes the first committed step in PAB biosynthesis. Mining of the golden larch root transcriptome revealed a large TPS family, including the monofunctional class I diTPS PxaTPS8, which converts geranylgeranyl diphosphate into a previously unknown 5,7-fused bicyclic diterpene, coined “pseudolaratriene.” Combined NMR and quantum chemical analysis verified the structure of pseudolaratriene, and co-occurrence with PxaTPS8 and PAB in P. amabilis tissues supports the intermediacy of pseudolaratriene in PAB metabolism. Although PxaTPS8 adopts the typical three-domain structure of diTPSs, sequence phylogeny places the enzyme with two-domain TPSs of mono- and sesqui-terpene biosynthesis. Site-directed mutagenesis of PxaTPS8 revealed several catalytic residues that, together with quantum chemical calculations, suggested a substantial divergence of PxaTPS8 from other TPSs leading to a distinct carbocation-driven reaction mechanism en route to the 5,7-trans-fused bicyclic pseudolaratriene scaffold. PxaTPS8 expression in microbial and plant hosts provided proof of concept for metabolic engineering of pseudolaratriene. PMID:28096378

  18. Calcium isotope fractionation in liquid chromatography with benzo-18-crown-6 resin in aqueous hydrobromic acid medium

    International Nuclear Information System (INIS)

    Sato, Takuya; Oi, Takao

    2015-01-01

    Liquid chromatography operated in a breakthrough mode was employed to study calcium isotope fractionation in the aqueous hydrobromic acid medium. Highly porous silica beads, the inner pores of which were embedded with a benzo-18-crown-6 ether resin, were used as column packing material. Enrichment of heavier isotopes of calcium was observed in the frontal part of respective calcium chromatograms. The values of the isotope fractionation coefficient were on the order of 10 -3 . The observed isotope fractionation coefficient was dependent on the concentration of hydrobromic acid in the calcium feed solution; a higher HBr concentration resulted in a smaller fractionation coefficient value. The present calcium isotope effects were most probably mass-dependent, indicating that they mostly came from isotope effects based on molecular vibration. Molecular orbital calculations supported the present experimental results in a qualitative fashion. Chromatography operated in aqueous HBr media is a better system of Ca isotope separation than that operated in aqueous HCl media. (author)

  19. Anaerobic biosynthesis of unsaturated fatty acids in the cyanobacterium, Oscillatoria limnetica

    Science.gov (United States)

    Jahnke, L. L.; Lee, B.; Sweeney, M. J.; Klein, H. P.

    1989-01-01

    The mechanism for synthesis of monounsaturated fatty acids under aerobic and anaerobic conditions was studied in the facultative anaerobic cyanobacterium, Oscillatoria limnetica. The hexadecenoic acid (C16:1) of aerobically grown O. limnetica was shown to contain both the delta 7 (79%) and delta 9 (21%) isomers, while the octadecenoic (C18:1) acid was entirely the delta 9 acid. Incorporation of [2-14C] acetate into the fatty acids under aerobic conditions resulted in synthesis of the delta 7 and delta 9 C16:1 and the delta 9 C18:1. Synthesis of unsaturated fatty acids in the presence of DCMU required sulfide. Anaerobic incubations in the presence of DCMU and sulfide (less than 0.003% atmospheric oxygen) resulted in a two-fold increase in monounsaturated fatty acids of both delta 7 and delta 9 C16:1 and delta 9 and delta 11 C18:1. The synthesis of these is characteristic of a bacterial-type, anaerobic pathway.

  20. Effect of phytic acid etchant on resin-dentin bonding: Monomer penetration and stability of dentin collagen.

    Science.gov (United States)

    Kong, Kalyan; Hiraishi, Noriko; Nassar, Mohannad; Otsuki, Masayuki; Yiu, Cynthia K Y; Tagami, Junji

    2017-07-01

    Phytic acid (IP6) works well as an etchant in dentin bonding to remove the smear layer due to its acidity and chelating effect. This study compared the etching effect of IP6 with phosphoric acid (PA) and ethylenediaminetetraacetic acid (EDTA) on resin-dentin bond strength, micromorphology of the etched dentin surface and nanoleakage formation along resin-dentin interfaces and compared the protecting effect against collagen degradation. Dentin disks and flat dentin surfaces were obtained from extracted human teeth. Specimens were etched with 35% PA (15s), 0.5M EDTA (30s) or 1% IP6 (30s). The surfaces and longitudinal sections of the etched dentin disks were observed using field emission scanning electron microscope (FE-SEM). An etch-and-rinse adhesive was used to create composite build up-specimens for microtensile bond strength (μTBS) testing and nanoleakage observation. To evaluate the effect on collagen degradation, demineralized bovine root dentin blocks were challenged with bacterial collagenase and then observed under light microscope. PA- and EDTA- treated groups showed significantly lower μTBS when compared to IP6-treated group. PA showed distinct nanoleakage and severe collagen degradation. Only slight nanoleakage was detected in IP6 group. IP6 showed better effect than EDTA in preventing collagen degradation induced by bacterial collagenase. IP6 effectively removed the smear layer and etched dentin, providing high bond strength values and causing minimal nanoleakage and slight collagen degradation. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  1. Biosynthesis of Essential Polyunsaturated Fatty Acids in Wheat Triggered by Expression of Artificial Gene

    Directory of Open Access Journals (Sweden)

    Daniel Mihálik

    2015-12-01

    Full Text Available The artificial gene D6D encoding the enzyme ∆6desaturase was designed and synthesized using the sequence of the same gene from the fungus Thamnidium elegans. The original start codon was replaced by the signal sequence derived from the wheat gene for high-molecular-weight glutenin subunit and the codon usage was completely changed for optimal expression in wheat. Synthesized artificial D6D gene was delivered into plants of the spring wheat line CY-45 and the gene itself, as well as transcribed D6D mRNA were confirmed in plants of T0 and T1 generations. The desired product of the wheat genetic modification by artificial D6D gene was the γ-linolenic acid. Its presence was confirmed in mature grains of transgenic wheat plants in the amount 0.04%–0.32% (v/v of the total amount of fatty acids. Both newly synthesized γ-linolenic acid and stearidonic acid have been detected also in leaves, stems, roots, awns, paleas, rachillas, and immature grains of the T1 generation as well as in immature and mature grains of the T2 generation. Contents of γ-linolenic acid and stearidonic acid varied in range 0%–1.40% (v/v and 0%–1.53% (v/v from the total amount of fatty acids, respectively. This approach has opened the pathway of desaturation of fatty acids and production of essential polyunsaturated fatty acids in wheat.

  2. Ascorbic Acid Biosynthesis and Brackish Water Acclimation in the Euryhaline Freshwater White-Rimmed Stingray, Himantura signifer.

    Directory of Open Access Journals (Sweden)

    Samuel Z H Wong

    Full Text Available L-gulono-γ-lactone oxidase (Gulo catalyzes the last step of ascorbic acid biosynthesis, which occurs in the kidney of elasmobranchs. This study aimed to clone and sequence gulonolactone oxidase (gulo from the kidney of the euryhaline freshwater stingray, Himantura signifer, and to determine the effects of acclimation from freshwater to brackish water (salinity 20 on its renal gulo mRNA expression and Gulo activity. We also examined the effects of brackish water acclimation on concentrations of ascorbate, dehydroascorbate and ascorbate + dehydroascorbate in the kidney, brain and gill. The complete cDNA coding sequence of gulo from the kidney of H. signifer contained 1323 bp coding for 440 amino acids. The expression of gulo was kidney-specific, and renal gulo expression decreased significantly by 67% and 50% in fish acclimated to brackish water for 1 day and 6 days, respectively. There was also a significant decrease in renal Gulo activity after 6 days of acclimation to brackish water. Hence, brackish water acclimation led to a decrease in the ascorbic acid synthetic capacity in the kidney of H. signifer. However, there were significant increases in concentrations of ascorbate and ascorbate + dehydroascorbate in the gills (after 1 or 6 days, and a significant increase in the concentration of ascorbate and a significant decrease in the concentration of dehydroascorbate in the brain (after 1 day of fish acclimated to brackish water. Taken together, our results indicate that H. signifer might experience greater salinity-induced oxidative stress in freshwater than in brackish water, possibly related to its short history of freshwater invasion. These results also suggest for the first time a possible relationship between the successful invasion of the freshwater environment by some euryhaline marine elasmobranchs and the ability of these elasmobranchs to increase the capacity of ascorbic acid synthesis in response to hyposalinity stress.

  3. The Fatty Acid Biosynthesis Enzyme FabI Plays a Key Role In the Development of Liver Stage Malarial Parasites

    Science.gov (United States)

    Yu, Min; Santha Kumar, T. R.; Nkrumah, Louis J.; Coppi, Alida; Retzlaff, Silke; Li, Celeste D.; Kelly, Brendan J.; Moura, Pedro A.; Lakshmanan, Viswanathan; Freundlich, Joel S.; Valderramos, Juan-Carlos; Vilcheze, Catherine; Siedner, Mark; Tsai, Jennifer H.-C.; Falkard, Brie; Sidhu, Amar bir Singh; Purcell, Lisa A.; Gratraud, Paul; Kremer, Laurent; Waters, Andy P.; Schiehser, Guy; Jacobus, David P.; Janse, Chris J.; Ager, Arba; Jacobs, William R.; Sacchettini, James C.; Heussler, Volker; Sinnis, Photini; Fidock, David A.

    2008-01-01

    SUMMARY Fatty acid biosynthesis has been viewed as an important biological function of and therapeutic target for Plasmodium falciparum asexual blood stage infection. This apicoplast-resident type II pathway, distinct from the mammalian type I process, includes FabI. Here, we report synthetic chemistry and transfection studies concluding that Plasmodium FabI is not the target of the antimalarial activity of the bacterial FabI inhibitor triclosan. Disruption of fabI in P. falciparum or the rodent parasite P. berghei does not impede blood stage growth. In contrast, mosquito-derived fabI-deficient P. berghei sporozoites are markedly less infective for mice and typically fail to complete liver stage development in vitro. This is characterized by an inability to form intra-hepatic merosomes that normally initiate blood stage infections. These data illuminate key differences between liver and blood stage parasites in their requirements for host versus de novo synthesized fatty acids, and create new prospects for stage-specific antimalarial interventions. PMID:19064257

  4. Transcriptional profiling of genes involved in ascorbic acid biosynthesis, recycling, and degradation during three leaf developmental stages in celery.

    Science.gov (United States)

    Huang, Wei; Wang, Guang-Long; Li, Hui; Wang, Feng; Xu, Zhi-Sheng; Xiong, Ai-Sheng

    2016-12-01

    Ascorbic acid (AsA) is an important nutrient in the human body and performs various healthy functions. With considerable medicinal properties, celery (Apium graveolens L.) could be a good source of AsA for human health. However, the biosynthetic, recycling, and degradation pathways of AsA in celery have yet to be characterized. To study the metabolic pathways involved in AsA, the genes involved in AsA biosynthesis, recycling, and degradation were isolated from celery, and their expression profiles and AsA levels were analyzed in the leaf blades and petioles of two celery varieties at three different growth stages. AsA levels were higher in 'Ventura' compared with 'Liuhehuangxinqin' in both tissues possibly because of different transcription levels of genes, such as L-galactose dehydrogenase (GalDH), L-galactono-1,4-lactone dehydrogenase (GalLDH), and glutathione reductase (GR). Results revealed that the D-mannose/L-galactose pathway may be the predominant pathway in celery, and the D-galacturonic acid pathway appeared to contribute largely to AsA accumulation in petioles than in leaf blades in 'Liuhehuangxinqin.' AsA contents are regulated by complex regulatory mechanisms and vary at different growth stages, tissues, and varieties in celery. The results provide novel insights into AsA metabolic pathways in leaf during celery growth and development.

  5. Genetic regulation by amino acids of specific membrane protein biosynthesis in isolated rat hepatocytes

    International Nuclear Information System (INIS)

    Chiles, T.C.; Handlogten, M.E.; Kilberg, M.S.

    1986-01-01

    Rat Hepatocytes in primary culture were incubated in amino acid-free (AAF) medium or amino acid-supplemented (AAS) medium for 2-6 hr. The effect of amino acid starvation on the synthesis of specific membrane proteins was monitored by including 3 H-leucine during the incubation. A crude plasma membrane fraction was prepared and then analyzed by 2-D gel electrophoresis followed by fluorography. Amino acid deprivation caused an induction of the synthesis of 5 of the 30 proteins studied. The ratio (AAF/-AAS) of cpm incorporated into the remaining 25 proteins was 0.8 +/- 0.2, whereas the ratio for the 5 proteins that showed amino acid-dependent synthesis ranged from 1.5 to 2.5. The presence of 4 μM actinomycin in the AAF medium completely blocked the starvation-induced synthesis of the 5 proteins tested, but did not alter significantly the ratio of cpm incorporated into the other 25 proteins. Binding studies involving ConA suggested a plasma membrane location for the 5 proteins. The molecular weight values of the starvation-induced proteins are 70, 66, 66, 67, and 45kD. Surface-labelling of intact cells and preparation of antibodies against the 5 proteins will be used to establish the subcellular location and to describe the amino acid-dependent synthesis of each in more detail

  6. Input to Resin Column Structural Analysis if Autocatalytic Resin Reaction Occurs in HB-Line Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Hallman, D.F.

    2001-07-10

    Solutions of plutonium in nitric acid are purified and concentrated using anion resin prior to precipitation. There have been instances of resin column explosions caused by autocatalytic reactions of anion resins in nitric acid within the DOE complex

  7. Biosynthesis of aromatic amino acids in Nocardia sp. 239 : effects of amino acid analogues on growth and regulatory enzymes

    NARCIS (Netherlands)

    Boer, L. de; Grobben, G.; Vrijbloed, J.W.; Dijkhuizen, L.

    1990-01-01

    Further steps required for overproduction of aromatic amino acids by a mutant strain of Nocardia sp. 239 (Noc 87-13), unable to grow on L-phenylalanine as a sole carbon and energy source, were investigated. A number of analogues of the aromatic amino acids displayed severe inhibitory effects on the

  8. Esterification of oleic acid in a three-phase, fixed-bed reactor packed with a cation exchange resin catalyst.

    Science.gov (United States)

    Son, Sung Mo; Kimura, Hiroko; Kusakabe, Katsuki

    2011-01-01

    Esterification of oleic acid was performed in a three-phase fixed-bed reactor with a cation exchange resin catalyst (Amberlyst-15) at high temperature, which was varied from 80 to 120 °C. The fatty acid methyl ester (FAME) yields in the fixed-bed reactor were increased with increases in the reaction temperature, methanol flow rate and bed height. Moreover, the FAME yields were higher than those obtained using a batch reactor due to an equilibrium shift toward the product that resulted from continuous evaporation of the produced water. In addition, there was no catalyst deactivation during the esterification of oleic acid. However, addition of sunflower oil to the oleic acid reduced the FAME yield obtained from simultaneous esterification and transesterification. The FAME yield was 97.5% at a reaction temperature of 100 °C in the fixed-bed with a height of 5 cm when the methanol and oleic acid feed rates were 8.6 and 9.0 mL/h, respectively. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Discovery and characterization of de novo sialic acid biosynthesis in the phylum Fusobacterium

    Science.gov (United States)

    Lewis, Amanda L; Robinson, Lloyd S; Agarwal, Kavita; Lewis, Warren G

    2016-01-01

    Sialic acids are nine-carbon backbone carbohydrates found in prominent outermost positions of glycosylated molecules in mammals. Mimicry of sialic acid (N-acetylneuraminic acid, Neu5Ac) enables some pathogenic bacteria to evade host defenses. Fusobacterium nucleatum is a ubiquitous oral bacterium also linked with invasive infections throughout the body. We employed multidisciplinary approaches to test predictions that F. nucleatum engages in de novo synthesis of sialic acids. Here we show that F. nucleatum sbsp. polymorphum ATCC10953 NeuB (putative Neu5Ac synthase) restores Neu5Ac synthesis to an Escherichia coli neuB mutant. Moreover, purified F. nucleatum NeuB participated in synthesis of Neu5Ac from N-acetylmannosamine and phosphoenolpyruvate in vitro. Further studies support the interpretation that F. nucleatum ATCC10953 NeuA encodes a functional CMP-sialic acid synthetase and suggest that it may also contain a C-terminal sialic acid O-acetylesterase. We also performed BLAST queries of F. nucleatum genomes, revealing that only 4/31 strains encode a complete pathway for de novo Neu5Ac synthesis. Biochemical studies including mass spectrometry were consistent with the bioinformatic predictions, showing that F. nucleatum ATCC10953 synthesizes high levels of Neu5Ac, whereas ATCC23726 and ATCC25586 do not express detectable levels above background. While there are a number of examples of sialic acid mimicry in other phyla, these experiments provide the first biochemical and genetic evidence that a member of the phylum Fusobacterium can engage in de novo Neu5Ac synthesis. PMID:27613803

  10. Biosynthesis of tylophora alkaloids

    International Nuclear Information System (INIS)

    Mulchandani, N.B.; Iyer, S.S.; Badheka, L.P.

    1974-01-01

    Using labelled precursors, biosynthesis of the tylophora alkaloids, tylophorine, tylophorinidine and tylophorinide has been investigated in Tylophora asthmatica plants. The radioactive precursors, phenylalanine-2- 14 C, benzoic acid-1- 14 C, benzoic acid-ring 14 C, acetate-2- 14 C, ornithine-5- 14 C, acetate-2- 14 C, ornithine-5- 14 C and cinnamic acid-2- 14 C were administered to the plants individually by wick technique. Tylophorine was isolated in each case and assayed for its radioactivity to find out the incorporation of the label into it. The results indicate that: (1) phenylalanine via cinnamic acid is an important precursor in the biosynthesis of tylophorine (2) orinithine participates in tylophorine biosynthesis via pyrroline and (3) tylophorinidine may be a direct precursor of tylophorine. (M.G.B.)

  11. Biochemical and Genetic Engineering of Diatoms for Polyunsaturated Fatty Acid Biosynthesis

    Directory of Open Access Journals (Sweden)

    Hong-Ye Li

    2014-01-01

    Full Text Available The role of diatoms as a source of bioactive compounds has been recently explored. Diatom cells store a high amount of fatty acids, especially certain polyunsaturated fatty acids (PUFAs. However, many aspects of diatom metabolism and the production of PUFAs remain unclear. This review describes a number of technical strategies, such as modulation of environmental factors (temperature, light, chemical composition of culture medium and culture methods, to influence the content of PUFAs in diatoms. Genetic engineering, a newly emerging field, also plays an important role in controlling the synthesis of fatty acids in marine microalgae. Several key points in the biosynthetic pathway of PUFAs in diatoms as well as recent progresses are also a critical part and are summarized here.

  12. Biochemical and genetic engineering of diatoms for polyunsaturated fatty acid biosynthesis.

    Science.gov (United States)

    Li, Hong-Ye; Lu, Yang; Zheng, Jian-Wei; Yang, Wei-Dong; Liu, Jie-Sheng

    2014-01-07

    The role of diatoms as a source of bioactive compounds has been recently explored. Diatom cells store a high amount of fatty acids, especially certain polyunsaturated fatty acids (PUFAs). However, many aspects of diatom metabolism and the production of PUFAs remain unclear. This review describes a number of technical strategies, such as modulation of environmental factors (temperature, light, chemical composition of culture medium) and culture methods, to influence the content of PUFAs in diatoms. Genetic engineering, a newly emerging field, also plays an important role in controlling the synthesis of fatty acids in marine microalgae. Several key points in the biosynthetic pathway of PUFAs in diatoms as well as recent progresses are also a critical part and are summarized here.

  13. Biosynthesis of Germacrene A Carboxylic Acid in Chicory Roots. Demonstration of a Cytochrome P450 (+)-Germacrene A Hydroxylase and NADP+-Dependent Sesquiterpenoid Dehydrogenase(s) Involved in Sesquiterpene Lactone Biosynthesis

    Science.gov (United States)

    de Kraker, Jan-Willem; Franssen, Maurice C. R.; Dalm, Marcella C. F.; de Groot, Aede; Bouwmeester, Harro J.

    2001-01-01

    Sprouts of chicory (Cichorium intybus), a vegetable grown in the dark, have a slightly bitter taste associated with the presence of guaianolides, eudesmanolides, and germacranolides. The committed step in the biosynthesis of these compounds is catalyzed by a (+)-germacrene A synthase. Formation of the lactone ring is the postulated next step in biosynthesis of the germacrene-derived sesquiterpene lactones. The present study confirms this hypothesis by isolation of enzyme activities from chicory roots that introduce a carboxylic acid function in the germacrene A isopropenyl side chain, which is necessary for lactone ring formation. (+)-Germacrene A is hydroxylated to germacra-1(10),4,11(13)-trien-12-ol by a cytochrome P450 enzyme, and is subsequently oxidized to germacra-1(10),4,11(13)-trien-12-oic acid by NADP+-dependent dehydrogenase(s). Both oxidized germacrenes were detected as their Cope-rearrangement products elema-1,3,11(13)-trien-12-ol and elema-1,3,11(13)-trien-12-oic acid, respectively. The cyclization products of germacra-1(10),4,11(13)-trien-12-ol, i.e. costol, were also observed. The (+)-germacrene A hydroxylase is inhibited by carbon monoxide (blue-light reversible), has an optimum pH at 8.0, and hydroxylates β-elemene with a modest degree of enantioselectivity. PMID:11299372

  14. COMPARATIVE STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTAL ENAMEL CONDITIONED WITH PHOSPHORIC ACID OR Nd: YAG LASER

    Directory of Open Access Journals (Sweden)

    EDUARDO Carlos de Paula

    1997-01-01

    Full Text Available This study has been focused on a comparison between the shear bond strength of a composite resin attached to dental enamel surface, after a 35% phosphoric acid etching and after a Nd:YAG laser irradiation with 165.8 J/cm2 of energy density per pulse. After etching and attaching resin to these surfaces, the specimens were thermocycled and then underwent the shearing bond strength tests at a speed of 5 mm/min. The results achieved, after statistical analysis with Student's t-test, showed that the adhesion was significantly greater in the 35% phosphoric acid treated group than in the group treated with the Nd:YAG laser, thus demonstrating the need for developing new studies to reach the ideal parameters for an effective enamel surface conditioning as well as specific adhesives and composite resins when Nd:YAG laser is used

  15. Effect of alcohols on elution chromatography of trivalent actinides and lanthanides using tertiary pyridine resin with hydrochloric acid-alcohol mixed solvents.

    Science.gov (United States)

    Ikeda, Atsushi; Suzuki, Tatsuya; Aida, Masao; Fujii, Yasuhiko; Itoh, Keisuke; Mitsugashira, Toshiaki; Hara, Mitsuo; Ozawa, Masaki

    2004-07-02

    Elution chromatography with a tertiary pyridine resin has been used to separate the trivalent actinides (An3+) from the lanthanides (Ln3+) using an alcoholic hydrochloric acid solvent. Trivalent Am and Cm were separated from the Ln by employing a 1 cm(phi) x 10 cm resin column with the mixed solvent system composed of concentrated hydrochloric acid (HCl) and alcohols. The distribution coefficients (Kd) and the separation factors between An and Ln (alpha(An)(Ln)) increased as the alcohol content of the solvent mixture increased. On the other hand, the Kd and alpha(An)(Ln) decreased drastically upon the addition of water to the solvent mixture. Among the four alcohols investigated (methanol, ethanol, n-propanol and n-butanol), the ethanol-HCl mixed solvent system showed the largest Kd and alpha(An)(Ln). The mechanism of adsorption for An and Ln cations on the pyridine resin is discussed in addition to the results presented herein.

  16. Regulation of indole-3-acetic acid biosynthesis by branched-chain amino acids in Enterobacter cloacae UW5.

    Science.gov (United States)

    Parsons, Cassandra V; Harris, Danielle M M; Patten, Cheryl L

    2015-09-01

    The soil bacterium Enterobacter cloacae UW5 produces the rhizosphere signaling molecule indole-3-acetic acid (IAA) via the indolepyruvate pathway. Expression of indolepyruvate decarboxylase, a key pathway enzyme encoded by ipdC, is upregulated by the transcription factor TyrR in response to aromatic amino acids. Some members of the TyrR regulon may also be controlled by branched-chain amino acids and here we show that expression from the ipdC promoter and production of IAA are downregulated by valine, leucine and isoleucine. Regulation of the IAA synthesis pathway by both aromatic and branched-chain amino acids suggests a broader role for this pathway in bacterial physiology, beyond plant interactions. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Establishment of a hepatocyte line for studying biosynthesis of long-chain polyunsaturated fatty acids from a marine teleost, the white-spotted spinefoot Siganus canaliculatus.

    Science.gov (United States)

    Liu, Y; Zhang, Q H; Dong, Y W; You, C H; Wang, S Q; Li, Y Q; Li, Y Y

    2017-08-01

    A hepatocyte line was established from the liver of white-spotted spinefoot Siganus canaliculatus to study the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFA). The cells from the line, designated S. canaliculatus hepatocyte line (SCHL), grew and multiplied well in Dulbecco's modified Eagle's medium (DMEM)-F12 medium supplemented with 20 mM 4-(2-hydroxyethyl) piperazine-1-ethanesulphonic acid (HEPES), 10% foetal bovine serum (FBS) and 0·5% rainbow trout Oncorhychus mykiss serum at 28° C, showing an epithelial-like morphology and the normal chromosome number of 48 (2n) and have been subcultured for over 60 passages. The identity of the hepatocytes was confirmed by periodic acid Schiff (PAS) staining. The mRNA expression of all genes encoding the key enzymes for LC-PUFA biosynthesis including two desaturases (Δ4 Fad and Δ6-Δ5 Fad) and two elongases (Elovl4 and Elovl5), were detected in all cells from passages 5 to 60 and their expression levels became stable after passage 35 and showed responses to various PUFA incubation. This is similar to the situation determined in the liver of S. canaliculatus that were fed diets containing different fatty acids. These results indicated that SCHL was successfully established and can provide an in vitro tool to investigate lipid metabolism and regulatory mechanisms of LC-PUFA biosynthesis in teleosts, especially marine species. © 2017 The Fisheries Society of the British Isles.

  18. Preparation of a ribonucleic acid-(polyamidoamine)-(zirconia-urea-formaldehyde resin) high-performance liquid affinity chromatographic stationary phase.

    Science.gov (United States)

    Lei, S; Yu, S; Zhao, C

    2001-07-01

    A preparative method for a high-performance liquid affinity chromatographic (HPLAC) stationary phase is described. The 3- to 5-microm nonporous composite spherical microparticles of zirconia and urea-formaldehyde (UF) resin are synthesized through the reaction of zirconyl chloride with hexamethylene tetra-amine and urea, and then it is used as the matrix of the HPLAC stationary phase of which the diameter and structure are determined by scanning electron microscopy. In a methanol medium, the polyamidoamine (PAMAM) starburst dentritic spacer arms are linked with the imido-groups on the surface of the matrix by the Michael addition reaction with methyl acrylate and the amination reaction with ethylene diamine. After repeating these steps in triplets, amine-terminated dentritic spacer arms with a generation of 3 are obtained. The topological structure of the spacer arms is examined by solid-state 13C NMR. The Br-substituted ribonucleic acid (RNA) ligand is obtained by the reaction of liquid bromine with RNA and bonded to the dendritic spacer arms of the matrix in a solution of NaOH (pH 9-11). The binding capacity of RNA is measured by UV spectrophotometry. A new type of stationary phase--RNA-(PAMAM)-(zirconia-UF resin--for HPLAC, which possesses starburst dendritic spacer arms, is synthesized and used for the separation of biological macromolecules.

  19. Purification of gamma-amino butyric acid (GABA) from fermentation of defatted rice bran extract by using ion exchange resin

    Science.gov (United States)

    Tuan Nha, Vi; Phung, Le Thi Kim; Dat, Lai Quoc

    2017-09-01

    Rice bran is one of the significant byproducts of rice processing with 10 %w/w of constitution of whole rice grain. It is rich in nutrient compounds, including glutamic acid. Thus, it could be utilized for the fermentation with Lactobateria for synthesis of GABA, a valuable bioactive for antihypertensive effects. However, the concentration and purity of GABA in fermentation broth of defatted rice bran extract is low for production of GABA drug. This research focused on the purification of GABA from the fermentation broth of defatted rice bran extract by using cation exchange resin. The results indicate that, the adsorption isotherm of GABA by Purelite C100 showed the good agreement with Freundlich model, with high adsorption capacity. The effects of pH and concentration of NaCl in eluent on the elution were also investigated. The obtained results show that, at the operating conditions of elution as follows: pH 6.5, 0.8 M of NaCl in eluent, 0.43 of bed volume; concentration of GABA in accumulative eluent, the purity and recovery yield of GABA were 743.8 ppm, 44.0% and 84.2%, respectively. Results imply that, it is feasible to apply cation exchange resin for purification of GABA from fermentation broth of defatted rice bran extract.

  20. Caenorhabditis elegans utilizes dauer pheromone biosynthesis to dispose of toxic peroxisomal fatty acids for cellular homoeostasis

    Science.gov (United States)

    Caenorhabditis elegans secretes a dauer pheromone or daumone composed of ascarylose and a fatty acid side chain, perception of which enables worms to gauge depletion of food or a high worm population density. As a result, worms enter the dauer state, a specific developmental stage capable of surviv...

  1. Precursor directed biosynthesis of odd-numbered fatty acids by different yeasts

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Kolouchová, I.; Sigler, Karel

    2015-01-01

    Roč. 60, č. 5 (2015), s. 457-464 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GAP503/11/0215; GA ČR GA14-00227S Institutional support: RVO:61388971 Keywords : PSEUDOZYMA-FLOCCULOSA * HEPTADECENOIC ACID * METHYL-ESTERS Subject RIV: EE - Microbiology, Virology Impact factor: 1.335, year: 2015

  2. A type-I diacylglycerol acyltransferase modulates triacylglycerol biosynthesis and fatty acid composition in the oleaginous microalga, Nannochloropsis oceanica.

    Science.gov (United States)

    Wei, Hehong; Shi, Ying; Ma, Xiaonian; Pan, Yufang; Hu, Hanhua; Li, Yantao; Luo, Ming; Gerken, Henri; Liu, Jin

    2017-01-01

    functional role of NoDGAT1A and sheds light on the underlying mechanism for the biosynthesis of various TAG species in N. oceanica. NoDGAT1A resides likely in cER and prefers to transfer C16 and C18 saturated/monounsaturated fatty acids to eukaryotic DAGs for TAG assembly. This work also provides insights into the rational genetic engineering of microalgae by manipulating rate-limiting enzymes such as DGAT to modulate TAG biosynthesis and fatty acid composition for biofuel production.

  3. Can heat treatment procedures of pre-hydrolyzed silane replace hydrofluoric acid in the adhesion of resin cement to feldspathic ceramic?

    Science.gov (United States)

    Cotes, Caroline; de Carvalho, Rodrigo Furtado; Kimpara, Estevão Tomomitsu; Leite, Fabíola Pessoa; Ozcan, Mutlu

    2013-12-01

    To evaluate the influence of heat treatment (HT) procedures of a pre-hydrolyzed silane on bond strength of resin cement to a feldspathic ceramic. Ceramic and composite blocks (N = 30) were divided into six groups (n = 5) and subjected to the following conditioning procedures: G1: 9.6% hydrofluoric acid (HF) for 20 s + silane (RelyX Ceramic Primer, 3M ESPE) + resin cement (Panavia F2.0, Kuraray) (control); G2: HF (20 s) + silane + heat treatment in furnace (HTF) (100°C, 2 min) + resin cement; G3: silane + HTF + resin cement; G4- HF (20 s) + silane + heat treatment with hot air (HTA) (50 ± 5°C for 1 min) + resin cement; G5: silane + HTA + resin cement; G6: silane + resin cement. The microtensile bond strength (MTBS) test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using a stereomicroscope and SEM to categorize the failure types. The data were statistically evaluated using one-way ANOVA and Tukey's test (5%). The control group (G1) showed no pre-test failures and presented significantly higher mean MTBS (16.01 ± 1.12 MPa) than did other groups (2.63 ± 1.05 to 12.55 ± 1.52 MPa) (p = 0.0001). In the groups where HF was not used, HTF (G3: 12.55 ± 1.52 MPa) showed significantly higher MTBS than did HTA (G5: 2.63 ± 1.05 MPa) (p silane either in a furnace or with the application of hot air cannot replace the use of HF gel for the adhesion of resin cement to feldspathic ceramic. Yet when mean bond strengths and incidence of pre-test failures are considered, furnace heat treatment delivered the second best results after the control group, being considerably better than hot air application.

  4. Characterization of Group V Dubnium Homologs on DGA Extraction Chromatography Resin from Nitric and Hydrofluoric Acid Matrices

    Energy Technology Data Exchange (ETDEWEB)

    Despotopulos, J D; Sudowe, R

    2012-02-21

    somewhere between Nb and Pa. Much more recent studies have examined the properties of Db from HNO{sub 3}/HF matrices, and suggest Db forms complexes similar to those of Pa. Very little experimental work into the behavior of element 114 has been performed. Thermochromatography experiments of three atoms of element 114 indicate that the element 114 is at least as volatile as Hg, At, and element 112. Lead was shown to deposit on gold at temperatures about 1000 C higher than the atoms of element 114. Results indicate a substantially increased stability of element 114. No liquid phase studies of element 114 or its homologs (Pb, Sn, Ge) or pseudo-homologs (Hg, Cd) have been performed. Theoretical predictions indicate that element 114 is should have a much more stable +2 oxidation state and neutral state than Pb, which would result in element 114 being less reactive and less metallic than Pb. The relativistic effects on the 7p{sub 1/2} electrons are predicted to cause a diagonal relationship to be introduced into the periodic table. Therefore, 114{sup 2+} is expected to behave as if it were somewhere between Hg{sup 2+}, Cd{sup 2+}, and Pb{sup 2+}. In this work two commercially available extraction chromatography resins are evaluated, one for the separation of Db homologs and pseudo?homologs from each other as well as from potential interfering elements such as Group IV Rf homologs and actinides, and the other for separation of element 114 homologs. One resin, Eichrom's DGA resin, contains a N,N,N',N'-tetra-n-octyldiglycolamide extractant, which separates analytes based on both size and charge characteristics of the solvated metal species, coated on an inert support. The DGA resin was examined for Db chemical systems, and shows a high degree of selectivity for tri-, tetra-, and hexavalent metal ions in multiple acid matrices with fast kinetics. The other resin, Eichrom's Pb resin, contains a di-t-butylcyclohexano 18-crown-6 extractant with isodecanol solvent

  5. Biosynthesis of N-glycolyneuraminic acid. The primary site of hydroxylation of N-acetylneuraminic acid is the cytosolic sugar nucleotide pool.

    Science.gov (United States)

    Muchmore, E A; Milewski, M; Varki, A; Diaz, S

    1989-12-05

    N-Glycolylneuraminic acid (Neu5Gc) is an oncofetal antigen in humans and is developmentally regulated in rodents. We have explored the biology of N-acetylneuraminic acid hydroxylase, the enzyme responsible for conversion of the parent sialic acid, N-acetylneuraminic acid (Neu5Ac) to Neu5Gc. We show that the major sialic acid in all compartments of murine myeloma cell lines is Neu5Gc. Pulse-chase analysis in these cells with the sialic acid precursor [6-3H]N-acetylmannosamine demonstrates that most of the newly synthesized Neu5Gc appears initially in the cytosolic low-molecular weight pool bound to CMP. The percentage of Neu5Gc on membrane-bound sialic acids closely parallels that in the CMP-bound pool at various times of chase, whereas that in the free sialic acid pool is very low initially, and rises only later during the chase. This implies that conversion from Neu5Ac to Neu5Gc occurs primarily while Neu5Ac is in its sugar nucleotide form. In support of this, the hydroxylase enzyme from a variety of tissues and cells converted CMP-Neu5Ac to CMP-Neu5Gc, but showed no activity towards free or alpha-glycosidically bound Neu5Ac. Furthermore, the majority of the enzyme activity is found in the cytosol. Studies with isolated intact Golgi vesicles indicate that CMP-Neu5Gc can be transported and utilized for transfer of Neu5Gc to glycoconjugates. The general properties of the enzyme have also been investigated. The Km for CMP-Neu5Ac is in the range of 0.6-2.5 microM. No activity can be detected against the beta-methylglycoside of Neu5Ac. On the other hand, inhibition studies suggest that the enzyme recognizes both the 5'-phosphate group and the pyrimidine base of the substrate. Taken together, the data allow us to propose pathways for the biosynthesis and reutilization of Neu5Gc, with initial conversion from Neu5Ac occurring primarily at the level of the sugar nucleotide. Subsequent release and reutilization of Neu5Gc could then account for the higher steady-state level

  6. Biosynthesis and Secretion of Indole-3-Acetic Acid and Its Morphological Effects on Tricholoma vaccinum-Spruce Ectomycorrhiza

    Science.gov (United States)

    Krause, Katrin; Henke, Catarina; Asiimwe, Theodore; Ulbricht, Andrea; Klemmer, Sandra; Schachtschabel, Doreen

    2015-01-01

    Fungus-derived indole-3-acetic acid (IAA), which is involved in development of ectomycorrhiza, affects both partners, i.e., the tree and the fungus. The biosynthesis pathway, excretion from fungal hyphae, the induction of branching in fungal cultures, and enhanced Hartig net formation in mycorrhiza were shown. Gene expression studies, incorporation of labeled compounds into IAA, heterologous expression of a transporter, and bioinformatics were applied to study the effect of IAA on fungal morphogenesis and on ectomycorrhiza. Tricholoma vaccinum produces IAA from tryptophan via indole-3-pyruvate, with the last step of this biosynthetic pathway being catalyzed by an aldehyde dehydrogenase. The gene ald1 was found to be highly expressed in ectomycorrhiza and induced by indole-3-acetaldehyde. The export of IAA from fungal cells is supported by the multidrug and toxic extrusion (MATE) transporter Mte1 found in T. vaccinum. The addition of IAA and its precursors induced elongated cells and hyphal ramification of mycorrhizal fungi; in contrast, in saprobic fungi such as Schizophyllum commune, IAA did not induce morphogenetic changes. Mycorrhiza responded by increasing its Hartig net formation. The IAA of fungal origin acts as a diffusible signal, influencing root colonization and increasing Hartig net formation in ectomycorrhiza. PMID:26231639

  7. Mutation in the key enzyme of sialic acid biosynthesis causes severe glomerular proteinuria and is rescued by N-acetylmannosamine.

    Science.gov (United States)

    Galeano, Belinda; Klootwijk, Riko; Manoli, Irini; Sun, MaoSen; Ciccone, Carla; Darvish, Daniel; Starost, Matthew F; Zerfas, Patricia M; Hoffmann, Victoria J; Hoogstraten-Miller, Shelley; Krasnewich, Donna M; Gahl, William A; Huizing, Marjan

    2007-06-01

    Mutations in the key enzyme of sialic acid biosynthesis, uridine diphospho-N-acetylglucosamine 2-epimerase/N-acetylmannosamine (ManNAc) kinase (GNE/MNK), result in hereditary inclusion body myopathy (HIBM), an adult-onset, progressive neuromuscular disorder. We created knockin mice harboring the M712T Gne/Mnk mutation. Homozygous mutant (Gne(M712T/M712T)) mice did not survive beyond P3. At P2, significantly decreased Gne-epimerase activity was observed in Gne(M712T/M712T) muscle, but no myopathic features were apparent. Rather, homozygous mutant mice had glomerular hematuria, proteinuria, and podocytopathy. Renal findings included segmental splitting of the glomerular basement membrane, effacement of podocyte foot processes, and reduced sialylation of the major podocyte sialoprotein, podocalyxin. ManNAc administration yielded survival beyond P3 in 43% of the Gne(M712T/M712T) pups. Survivors exhibited improved renal histology, increased sialylation of podocalyxin, and increased Gne/Mnk protein expression and Gne-epimerase activities. These findings establish this Gne(M712T/M712T) knockin mouse as what we believe to be the first genetic model of podocyte injury and segmental glomerular basement membrane splitting due to hyposialylation. The results also support evaluation of ManNAc as a treatment not only for HIBM but also for renal disorders involving proteinuria and hematuria due to podocytopathy and/or segmental splitting of the glomerular basement membrane.

  8. Environmental DNA-encoded antibiotics fasamycins A and B inhibit FabF in type II fatty acid biosynthesis.

    Science.gov (United States)

    Feng, Zhiyang; Chakraborty, Debjani; Dewell, Scott B; Reddy, Boojala Vijay B; Brady, Sean F

    2012-02-15

    In a recent study of polyketide biosynthetic gene clusters cloned directly from soil, we isolated two antibiotics, fasamycins A and B, which showed activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. To identify the target of the fasamycins, mutants with elevated fasamycin A minimum inhibitory concentrations were selected from a wild-type culture of E. faecalis OG1RF. Next-generation sequencing of these mutants, in conjunction with in vitro biochemical assays, showed that the fasamycins inhibit FabF of type II fatty acid biosynthesis (FASII). Candidate gene overexpression studies also showed that fasamycin resistance is conferred by fabF overexpression. On the basis of comparisons with known FASII inhibitors and in silico docking studies, the chloro-gem-dimethyl-anthracenone substructure seen in the fasamycins is predicted to represent a naturally occurring FabF-specific antibiotic pharmacophore. Optimization of this pharmacophore should yield FabF-specific antibiotics with increased potencies and differing spectra of activity. This study demonstrates that culture-independent antibiotic discovery methods have the potential to provide access to novel metabolites with modes of action that differ from those of antibiotics currently in clinical use.

  9. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from sup 18 O incorporation patterns

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. (Michigan State University, East Lansing (USA))

    1989-12-01

    Previous labeling studies of abscisic acid (ABA) with {sup 18}O{sub 2} have been mainly conducted with water-stressed leaves. In this study, {sup 18}O incorporation into ABA of stressed leaves of various species was compared with {sup 18}O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), {sup 18}O was most abundant in the carboxyl group, whereas incorporation of a second and third {sup 18}O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in {sup 18}O{sub 2}. ABA from turgid bean leaves showed significant {sup 18}O incorporation, again with highest {sup 18}O enrichment in the carboxyl group. On the basis of {sup 18}O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid.

  10. 2-Oxoglutarate: linking TCA cycle function with amino acid, glucosinolate, flavonoid, alkaloid, and gibberellin biosynthesis.

    Science.gov (United States)

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

    2014-01-01

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

  11. 2-Oxoglutarate: linking TCA cycle function with amino acid, glucosinolate, flavonoid, alkaloid and gibberellin biosynthesis

    Directory of Open Access Journals (Sweden)

    Wagner L. Araújo

    2014-10-01

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

  12. Metabolic engineering of medium-chain fatty acid biosynthesis in Nicotiana benthamiana plant leaf lipids

    Science.gov (United States)

    Reynolds, Kyle B.; Taylor, Matthew C.; Zhou, Xue-Rong; Vanhercke, Thomas; Wood, Craig C.; Blanchard, Christopher L.; Singh, Surinder P.; Petrie, James R.

    2015-01-01

    Various research groups are investigating the production of oil in non-seed biomass such as leaves. Recently, high levels of oil accumulation have been achieved in plant biomass using a combination of biotechnological approaches which also resulted in significant changes to the fatty acid composition of the leaf oil. In this study, we were interested to determine whether medium-chain fatty acids (MCFA) could be accumulated in leaf oil. MCFA are an ideal feedstock for biodiesel and a range of oleochemical products including lubricants, coatings, and detergents. In this study, we explore the synthesis, accumulation, and glycerolipid head-group distribution of MCFA in leaves of Nicotiana benthamiana after transient transgenic expression of C12:0-, C14:0-, and C16:0-ACP thioesterase genes. We demonstrate that the production of these MCFA in leaf is increased by the co-expression of the WRINKLED1 (WRI1) transcription factor, with the lysophosphatidic acid acyltransferase (LPAAT) from Cocos nucifera being required for the assembly of tri-MCFA TAG species. We also demonstrate that the newly-produced MCFA are incorporated into the triacylglycerol of leaves in which WRI1 + diacylglycerol acyltransferase1 (DGAT1) genes are co-expressed for increased oil accumulation. PMID:25852716

  13. Substituted Caffeic and Ferulic Acid Phenethyl Esters: Synthesis, Leukotrienes Biosynthesis Inhibition, and Cytotoxic Activity

    Directory of Open Access Journals (Sweden)

    Pier Morin

    2017-07-01

    Full Text Available Glioblastoma multiforme (GBM is an aggressive brain tumor that correlates with short patient survival and for which therapeutic options are limited. Polyphenolic compounds, including caffeic acid phenethyl ester (CAPE, 1a, have been investigated for their anticancer properties in several types of cancer. To further explore these properties in brain cancer cells, a series of caffeic and ferulic acid esters bearing additional oxygens moieties (OH or OCH3 were designed and synthesized. (CAPE, 1a, but not ferulic acid phenethyl ester (FAPE, 1b, displayed substantial cytotoxicity against two glioma cell lines. Some but not all selected compounds derived from both (CAPE, 1a and (FAPE, 1b also displayed cytotoxicity. All CAPE-derived compounds were able to significantly inhibit 5-lipoxygenase (5-LO, however FAPE-derived compounds were largely ineffective 5-LO inhibitors. Molecular docking revealed new hydrogen bonds and π-π interactions between the enzyme and some of the investigated compounds. Overall, this work highlights the relevance of exploring polyphenolic compounds in cancer models and provides additional leads in the development of novel therapeutic strategies in gliomas.

  14. SOLVENT EFFECTS ON THE HYDRATION OF CYCLOHEXENE CATALYZED BY A STRONG ACID ION-EXCHANGE RESIN .3. EFFECT OF SULFOLANE ON THE EQUILIBRIUM CONVERSION

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    The liquid-phase hydration of cyclohexene, a pseudo-first-order reversible reaction catalyzed by a strong acid ion-exchange resin, was investigated in solvent mixtures of water and sulfolane. Macroporous Amberlite XE 307 was used because of its superior catalytic activity. Chemical equilibrium

  15. Properties of the Carboxylate ion exchange resins

    International Nuclear Information System (INIS)

    Allard, Bert; Dario, Maarten; Boren, Hans; Torstenfelt, Boerje; Puigdomenech, Ignasi; Johansson, Claes

    2002-09-01

    Weakly acidic, carboxylic resin has been selected, together with strong base anion resins, for water purification at the Forsmark 1 and 2 reactors. For the strong (but not the weak) ion exchange resin the Nuclear Power Inspectorate has given permission to dispose the spent resins in the SFR 1 (the Final Repository for Radioactive Operational Waste). This report gives a review of the carboxylic resins and comes to the conclusion that the resins are very stable and that there should not exist any risks for increased leaching of radionuclides from SFR 1 if these resins are disposed (compared to the strong resins)

  16. In silico analysis of amino acid biosynthesis and proteolysis in Lactobacillus delbrueckii subsp. bulgaricus 2038 and the implications for bovine milk fermentation.

    Science.gov (United States)

    Zheng, Huajun; Liu, Enuo; Hao, Pei; Konno, Tomonobu; Oda, Munehiro; Ji, Zai-Si

    2012-08-01

    The amino acid biosynthesis pathway and proteolytic system of Lactobacillus delbrueckii subsp. bulgaricus 2038 (L. bulgaricus 2038), a mainstay of large-scale yogurt production, were modeled based on its genomic sequence. L. bulgaricus 2038 retains more potential for amino acid synthesis and a more powerful proteolytic system than other L. bulgaricus strains, but favors amino acid uptake over de novo synthesis. Free amino acids and peptides in bovine milk provide the main nitrogen sources; whey is more important than casein for L. bulgaricus during fermentation. Free amino acids are imported by amino acid permeases and by ABC-type transport systems whereas exogenous oligopeptides are imported by ABC-type proteins only. Histidine is neither synthesized nor imported singly, which might explain why L. bulgaricus cannot grow in synthetic media.

  17. BIOCHEMICAL AND GENETIC CHARACTERIZATION OF AN EARLY STEP IN A NOVEL PATHWAY FOR THE BIOSYNTHESIS OF AROMATIC AMINO ACIDS AND P-AMINOBENZOIC ACID IN THE ARCHAEON METHANOCOCCUS MARIPALUDIS

    Science.gov (United States)

    Methanococcus maripaludis is a strictly anaerobic, methane-producing archaeon and facultative autotroph capable of biosynthesizing all the amino acids and vitamins required for growth. In this work, the novel 6-deoxy-5-ketofructose-1-phosphate (DKFP) pathway for the biosynthesis ...

  18. Fatty acid biosynthesis VII. Substrate control of chain-length of products synthesised by rat liver fatty acid synthetase

    DEFF Research Database (Denmark)

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

    1970-01-01

    - 1. Gas-liquid and paper chromatography have been used to determine the chain-lengths of fatty acids synthesised by purified rat liver fatty acid synthetase from [1-14C]acetyl-CoA, [1,3-14C2]malonyl-CoA and from [1-14C]acetyl-CoA plus partially purified rat liver acetyl-CoA carboxylase. - 2....... A wide range (C4:0–C18:0) of fatty acids was synthesised and the proportions were modified by substrate concentrations in the same manner as for purified rabbit mammary gland fatty acid synthetase. - 3. The relative amount of radioactivity incorporated from added acetyl-CoA and malonyl-CoA depended...... on the substrate concentrations used. At excess acetyl-CoA to malonyl-CoA, greater amounts of acetyl-CoA were incorporated than theoretically expected from the malonyl-CoA pathway. At excess malonyl-CoA, less acetyl-CoA was incorporated than theoretically expected. - 4. An increase in the chain-length of fatty...

  19. Brassinosteroids Improve Quality of Summer Tea by Balancing Biosynthesis of Polyphenols and Amino Acids in Camellia sinensis L.

    Directory of Open Access Journals (Sweden)

    Xin Li

    2016-08-01

    Full Text Available Summer grown green tea is less popular due to bitterness and high astringency that are attributed to high levels of tea polyphenol (TP and low levels of amino acids (AA in tea leaves (Camellia sinensis L.. Brassinosteroids (BRs, a group of steroidal plant hormones can regulate primary and secondary metabolism in a range of plant species under both normal and stress conditions. However, specific effects of BRs on the photosynthesis of tea plants and the quality of summer green tea are largely unknown. Here we show that 24-epibrassinolide (EBR, a bioactive BR, promoted photosynthesis in tea plants in a concentration-dependent manner. Stimulation in photosynthesis by EBR resulted in an increased summer tea yield. Although all tested concentrations (0.01, 0.05, 0.1, 0.5 and 1.0 ppm increased concentrations of TP and AA, a moderate concentration of EBR (0.5 ppm caused the highest decrease in TP to AA ratio, an important feature of quality tea. Time-course analysis using 0.5 ppm EBR as foliar spray revealed that TP or AA concentration increased as early as 3 h after EBR application, reaching the highest peak at 24 h and that remained more or less stable. Importantly, such changes in TP and AA concentration by EBR resulted in a remarkably decreased but stable TP to AA ratio at 24 h and onward. Furthermore, concentrations of catechins and theanine increased, while that of caffeine remained unaltered following treatment with EBR. EBR improved activity of phenylalanine ammonia-lyase (PAL and glutamine: 2-oxoglutarate (GOGAT enzymes involved in catechins and theanine biosynthesis, respectively. Transcript analysis revealed that transcript levels of CsPAL and CsGS peaked as early as 6 h, while that of CsGOGAT peaked at 12 h following application of EBR, implying that EBR increased the concentration of TP and AA by inducing their biosynthesis. These results suggest a positive role of BR in enhancing green tea quality, which might have potential implication

  20. Importance of the Long-Chain Fatty Acid Beta-Hydroxylating Cytochrome P450 Enzyme YbdT for Lipopeptide Biosynthesis in Bacillus subtilis Strain OKB105

    Directory of Open Access Journals (Sweden)

    Michael J. McInerney

    2011-03-01

    Full Text Available Bacillus species produce extracellular, surface-active lipopeptides such as surfactin that have wide applications in industry and medicine. The steps involved in the synthesis of 3-hydroxyacyl-coenzyme A (CoA substrates needed for surfactin biosynthesis are not understood. Cell-free extracts of Bacillus subtilis strain OKB105 synthesized lipopeptide biosurfactants in presence of L-amino acids, myristic acid, coenzyme A, ATP, and H2O2, which suggested that 3-hydroxylation occurs prior to CoA ligation of the long chain fatty acids (LCFAs. We hypothesized that YbdT, a cytochrome P450 enzyme known to beta-hydroxylate LCFAs, functions to form 3-hydroxy fatty acids for lipopeptide biosynthesis. An in-frame mutation of ybdT was constructed and the resulting mutant strain (NHY1 produced predominantly non-hydroxylated lipopeptide with diminished biosurfactant and beta-hemolytic activities. Mass spectrometry showed that 95.6% of the fatty acids in the NHY1 biosurfactant were non-hydroxylated compared to only ~61% in the OKB105 biosurfactant. Cell-free extracts of the NHY1 synthesized surfactin containing 3-hydroxymyristic acid from 3-hydroxymyristoyl-CoA at a specific activity similar to that of the wild type (17 ± 2 versus 17.4 ± 6 ng biosurfactant min−1·ng·protein−1, respectively. These results showed that the mutation did not affect any function needed to synthesize surfactin once the 3-hydroxyacyl-CoA substrate was formed and that YbdT functions to supply 3-hydroxy fatty acid for surfactin biosynthesis. The fact that YbdT is a peroxidase could explain why biosurfactant production is rarely observed in anaerobically grown Bacillus species. Manipulation of LCFA specificity of YbdT could provide a new route to produce biosurfactants with activities tailored to specific functions.

  1. Catalytic Upgrading of bio-oil using 1-octene and 1-butanol over sulfonic acid resin catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhijun; Wang, Qingwen; Tripathi, Prabhat; Pittman, Charles U.

    2011-02-04

    Raw bio-oil from fast pyrolysis of biomass must be refined before it can be used as a transporation fuel, a petroleum refinery feed or for many other fuel uses. Raw bio-oil was upgraded with the neat model olefin, 1-octene, and with 1-octene/1-butanol mixtures over sulfonic acid resin catalysts frin 80 to 150 degrees celisus in order to simultaneously lower water content and acidity and to increase hydrophobicity and heating value. Phase separation and coke formation were key factors limiting the reaction rate during upgrading with neat 1-octene although octanols were formed by 1-octene hydration along with small amounts of octyl acetates and ethers. GC-MS analysis confirmed that olefin hydration, carboxylic acid esterification, acetal formation from aldehydes and ketones and O- and C-alkylations of phenolic compounds occurred simultaneously during upgrading with 1-octene/1-butanol mixtures. Addition of 1-butanol increased olefin conversion dramatically be reducing mass transfer restraints and serving as a cosolvent or emulsifying agent. It also reacted with carboxylic acids and aldehydes/ketones to form esters, and acetals, respectively, while also serving to stabilize bio-oil during heating. 1-Butanol addition also protected the catalysts, increasing catalyst lifetime and reducing or eliminationg coking. Upgrading sharply increased ester content and decreased the amounts of levoglucosan, polyhydric alcohols and organic acids. Upgrading lowered acidity (pH value rise from 2.5 to >3.0), removed the uppleasant ordor and increased hydrocarbon solubility. Water content decreased from 37.2% to < 7.5% dramatically and calorific value increased from 12.6 MJ kg to about 30.0 MJ kg.

  2. Biosynthesis of N-glycolyneuraminic acid. The primary site of hydroxylation of N-acetylneuraminic acid is the cytosolic sugar nucleotide pool

    Energy Technology Data Exchange (ETDEWEB)

    Muchmore, E.A.; Milewski, M.; Varki, A.; Diaz, S. (San Diego Veterans Administration Medical Center, CA (USA))

    1989-12-05

    N-Glycolylneuraminic acid (Neu5Gc) is an oncofetal antigen in humans and is developmentally regulated in rodents. We have explored the biology of N-acetylneuraminic acid hydroxylase, the enzyme responsible for conversion of the parent sialic acid, N-acetylneuraminic acid (Neu5Ac) to Neu5Gc. We show that the major sialic acid in all compartments of murine myeloma cell lines is Neu5Gc. Pulse-chase analysis in these cells with the sialic acid precursor (6-3H)N-acetylmannosamine demonstrates that most of the newly synthesized Neu5Gc appears initially in the cytosolic low-molecular weight pool bound to CMP. The percentage of Neu5Gc on membrane-bound sialic acids closely parallels that in the CMP-bound pool at various times of chase, whereas that in the free sialic acid pool is very low initially, and rises only later during the chase. This implies that conversion from Neu5Ac to Neu5Gc occurs primarily while Neu5Ac is in its sugar nucleotide form. In support of this, the hydroxylase enzyme from a variety of tissues and cells converted CMP-Neu5Ac to CMP-Neu5Gc, but showed no activity towards free or alpha-glycosidically bound Neu5Ac. Furthermore, the majority of the enzyme activity is found in the cytosol. Studies with isolated intact Golgi vesicles indicate that CMP-Neu5Gc can be transported and utilized for transfer of Neu5Gc to glycoconjugates. The general properties of the enzyme have also been investigated. The Km for CMP-Neu5Ac is in the range of 0.6-2.5 microM. No activity can be detected against the beta-methylglycoside of Neu5Ac. On the other hand, inhibition studies suggest that the enzyme recognizes both the 5'-phosphate group and the pyrimidine base of the substrate. Taken together, the data allow us to propose pathways for the biosynthesis and reutilization of Neu5Gc.

  3. Manipulation of Glutathione and Amino Acid Biosynthesis in the Chloroplast1

    Science.gov (United States)

    Noctor, Graham; Arisi, Ana-Carolina M.; Jouanin, Lise; Foyer, Christine H.

    1998-01-01

    Poplars (Populus tremula × Populus alba) were transformed to overexpress Escherichia coli γ-glutamylcysteine synthetase (γ-ECS) or glutathione synthetase in the chloroplast. Five independent lines of each transformant strongly expressed the introduced gene and possessed markedly enhanced activity of the gene product. Glutathione (GSH) contents were unaffected by high chloroplastic glutathione synthetase activity. Enhanced chloroplastic γ-ECS activity markedly increased γ-glutamylcysteine and GSH levels. These effects are similar to those previously observed in poplars overexpressing these enzymes in the cytosol. Similar to cytosolic γ-ECS overexpression, chloroplastic overexpression did not deplete foliar cysteine or methionine pools and did not lead to morphological changes. Light was required for maximal accumulation of GSH in poplars overexpressing γ-ECS in the chloroplast. High chloroplastic, but not cytosolic, γ-ECS activities were accompanied by increases in amino acids synthesized in the chloroplast. We conclude that (a) GSH synthesis can occur in the chloroplast and the cytosol and may be up-regulated in both compartments by increased γ-ECS activity, (b) interactions between GSH synthesis and the pathways supplying the necessary substrates are similar in both compartments, and (c) chloroplastic up-regulation of GSH synthesis is associated with an activating effect on the synthesis of specific amino acids formed in the chloroplast. PMID:9765532

  4. Valorizing Dairy Waste: Thermophilic Biosynthesis of a Novel Ascorbic Acid Derivative.

    Science.gov (United States)

    Yang, Jingwen; Pérez, Bianca; Anankanbil, Sampson; Li, Jingbo; Zhou, Ye; Gao, Renjun; Guo, Zheng

    2017-10-18

    l-Ascorbic acid (l-AA) is an essential nutrient that is extremely unstable and cannot be synthesized by the human body. Therefore, attempts have been performed to develop biologically active l-AA derivatives with improved stability. This work presents a facile, scalable, and efficient enzymatic transgalactosylation of lactose to l-AA using β-glucosidase (TN0602) from Thermotoga naphthophila RKU-10. β-Glucosidase TN0602 displays high transgalactosylation activity at pH 5.0, 75 °C, and l-AA/lactose ratio of 2:1 to form a novel l-AA derivative [2-O-β-d-galactopyranosyl-l-ascorbic acid (l-AA-Gal)] with a maximal productivity of 138.88 mmol L -1 in 12 h, which is higher than most reports of enzymatic synthesis of l-AA-α-glucoside. Synthetic l-AA-Gal retains most l-AA antioxidant capability and presents dramatically higher stability than l-AA in an oxidative environment (Cu 2+ ). In conclusion, this work reports a new way to valorize dairy waste lactose into a novel molecule l-AA-Gal, which could be a promising l-AA derivative to be used in a wide range of applications.

  5. Ethylene promotes mycelial growth and ganoderic acid biosynthesis in Ganoderma lucidum.

    Science.gov (United States)

    Zhang, Guang; Ren, Ang; Wu, Fengli; Yu, Hanshou; Shi, Liang; Zhao, Mingwen

    2017-02-01

    To investigate the effects of ethylene, in the form of ethephon (2-chloroethylphosphonic acid), on mycelial growth and ganoderic acid (GA) accumulation in the higher basidiomycete Ganoderma lucidum. Treatment with both 10 and 15 mM ethephon enhanced the growth of G. lucidum on solid CYM plates and in CYM liquid medium. After optimization using response surface methodology, GA reached 33 mg/g dry cell weight (DW), an increase of 90 %, compared with the control. Lanosterol and squalene contents were 31 and 2.4 μg/g DW, being increased by 1.2- and 0.6-fold, respectively, in response to ethephon. Additionally, the transcriptional levels of hydroxymethylglutaryl-CoA reductase, squalene synthase and oxidosqualene cyclase were up-regulated by 2.6-, 4.3- and 3.8-fold, respectively, compared with the control group. This approach provides an efficient strategy for improving GA accumulation in G. lucidum, with potential future applications.

  6. Consequences of enamel preparation with sodium hypochlorite, polyacrylic and phosphoric acids for the bonding of brackets with resin-modified glass ionomer cements

    OpenAIRE

    Trindade, Alessandra Marques; Pereira, Tatiana Bahia Junqueira; Smith Neto, Perrin; Horta, Martinho Campolina Rebello; Pithon, Matheus Melo; Akaki, Emílio; Oliveira, Dauro Douglas

    2013-01-01

    The aim of this study was to evaluate the effects of deproteinization with 5.25% sodium hypochlorite (NaOCl) prior to enamel conditioning with 10% polyacrylic acid (PAA) and 35% phosphoric acid (PA) on the bond strength (BS) of brackets bonded with resin-modified glass ionomer cement (RMGIC). One hundred human premolars extracted for orthodontic reasons were divided into 5 groups (n = 20 in each group): G1 (control), enamel conditioning with PA, application of adhesive and bonding of brackets...

  7. Effect Of Sodium Hypochlorite And Peracetic Acid On The Surface Roughness Of Acrylic Resin Polymerized By Heated Water For Short And Long Cycles.

    OpenAIRE

    Sczepanski, Felipe; Sczepanski, Claudia Roberta Brunnquell; Berger, Sandrine Bittencourt; Consani, Rafael Leonardo Xediek; Gonini-Júnior, Alcides; Guiraldo, Ricardo Danil

    2015-01-01

    Objective: To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). Materials and Methods: The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, di...

  8. Effect of experimental acid/base conditioner on microtensile bond strength of 4-META/MMA-TBB resin to dentin after long-term water immersion.

    Science.gov (United States)

    Soeno, Kohyoh; Taira, Yohsuke; Ito, Shuichi

    2012-01-01

    An experimental conditioner (Exp), which was an aqueous solution of 10% ascorbic acid and 5% ferric chloride, was prepared in this study. This study evaluated the effect of Exp on the microtensile bond strength between a self-curing resin and dentin after long-term water immersion. Flat human dentin surfaces were sequentially pretreated with 40% phosphoric acid, 10% sodium hypochlorite, and Exp. Surface pretreatment with an aqueous solution of 10% citric and 3% ferric chloride (10-3) was used as a control. Composite resin rods were bonded to pretreated dentin surfaces using 4-META/MMA-TBB resin. Microtensile bond strengths were evaluated after water immersion at 24 h, 12 months, 24 months, and 36 months. At each immersion period, the bond strength of Exp was significantly higher than that of 10-3. After 36 months, Exp showed no significant decrease in microtensile bond strength, but 10-3 showed significant reductions. Pretreatment with experimental acid/base conditioner markedly improved the bonding durability of 4-META/MMA-TBB resin to human dentin when compared against the conventional 10-3 treatment.

  9. Biosynthesis of Polyunsaturated Fatty Acids in Sea Urchins: Molecular and Functional Characterisation of Three Fatty Acyl Desaturases from Paracentrotus lividus (Lamark 1816).

    Science.gov (United States)

    Kabeya, Naoki; Sanz-Jorquera, Alicia; Carboni, Stefano; Davie, Andrew; Oboh, Angela; Monroig, Oscar

    2017-01-01

    Sea urchins are broadly recognised as a delicacy and their quality as food for humans is highly influenced by their diet. Lipids in general and the long-chain polyunsaturated fatty acids (LC-PUFA) in particular, are essential nutrients that determine not only the nutritional value of sea urchins but also guarantee normal growth and reproduction in captivity. The contribution of endogenous production (biosynthesis) of LC-PUFA in sea urchins remained unknown. Using Paracentrotus lividus as our model species, we aimed to characterise both molecularly and functionally the repertoire of fatty acyl desaturases (Fads), key enzymes in the biosynthesis of LC-PUFA, in sea urchins. Three Fads, namely FadsA, FadsC1 and FadsC2, were characterised. The phylogenetic analyses suggested that the repertoire of Fads within the Echinodermata phylum varies among classes. On one hand, orthologues of the P. lividus FadsA were found in other echinoderm classes including starfishes, brittle stars and sea cucumbers, thus suggesting that this desaturase is virtually present in all echinoderms. Contrarily, the FadsC appears to be sea urchin-specific desaturase. Finally, a further desaturase termed as FadsB exists in starfishes, brittle stars and sea cucumbers, but appears to be missing in sea urchins. The functional characterisation of the P. lividus Fads confirmed that the FadsA was a Δ5 desaturase with activity towards saturated and polyunsaturated fatty acids (FA). Moreover, our experiments confirmed that FadsA plays a role in the biosynthesis of non-methylene interrupted FA, a group of compounds typically found in marine invertebrates. On the other hand, both FadsC desaturases from P. lividus showed Δ8 activity. The present results demonstrate that P. lividus possesses desaturases that account for all the desaturation reactions required to biosynthesis the physiological essential eicosapentaenoic and arachidonic acids through the so-called "Δ8 pathway".

  10. Biosynthesis of Polyunsaturated Fatty Acids in Sea Urchins: Molecular and Functional Characterisation of Three Fatty Acyl Desaturases from Paracentrotus lividus (Lamark 1816.

    Directory of Open Access Journals (Sweden)

    Naoki Kabeya

    Full Text Available Sea urchins are broadly recognised as a delicacy and their quality as food for humans is highly influenced by their diet. Lipids in general and the long-chain polyunsaturated fatty acids (LC-PUFA in particular, are essential nutrients that determine not only the nutritional value of sea urchins but also guarantee normal growth and reproduction in captivity. The contribution of endogenous production (biosynthesis of LC-PUFA in sea urchins remained unknown. Using Paracentrotus lividus as our model species, we aimed to characterise both molecularly and functionally the repertoire of fatty acyl desaturases (Fads, key enzymes in the biosynthesis of LC-PUFA, in sea urchins. Three Fads, namely FadsA, FadsC1 and FadsC2, were characterised. The phylogenetic analyses suggested that the repertoire of Fads within the Echinodermata phylum varies among classes. On one hand, orthologues of the P. lividus FadsA were found in other echinoderm classes including starfishes, brittle stars and sea cucumbers, thus suggesting that this desaturase is virtually present in all echinoderms. Contrarily, the FadsC appears to be sea urchin-specific desaturase. Finally, a further desaturase termed as FadsB exists in starfishes, brittle stars and sea cucumbers, but appears to be missing in sea urchins. The functional characterisation of the P. lividus Fads confirmed that the FadsA was a Δ5 desaturase with activity towards saturated and polyunsaturated fatty acids (FA. Moreover, our experiments confirmed that FadsA plays a role in the biosynthesis of non-methylene interrupted FA, a group of compounds typically found in marine invertebrates. On the other hand, both FadsC desaturases from P. lividus showed Δ8 activity. The present results demonstrate that P. lividus possesses desaturases that account for all the desaturation reactions required to biosynthesis the physiological essential eicosapentaenoic and arachidonic acids through the so-called "Δ8 pathway".

  11. Preparation and characterization of anion exchange resin decorated with magnetite nanoparticles for removal of p-toluic acid from aqueous solution

    Science.gov (United States)

    Davarpanah, Morteza; Ahmadpour, Ali; Rohani Bastami, Tahereh

    2015-02-01

    Polystyrene resin was covalently functionalized with diethanolamine and then decorated with magnetite nanoparticles by a novel and simple co-precipitation method using iron(II) sulfate as precursor. The products were characterized by Fourier transform infrared spectroscopy, elemental analysis, X-ray diffraction, Mössbauer spectroscopy, field-emission scanning electron microscopy and vibrating sample magnetometer. Adsorption of p-toluic acid (p-TA) onto magnetite-decorated polystyrene (MAG-PS) was studied and compared with that of diethanolamine-functionalized polystyrene and a commercial anion exchange resin. Results showed that the magnetite nanoparticles with an average size of 20.4 nm were successfully formed on the surface of polystyrene resin, and MAG-PS was exhibited high affinity for the removal of p-TA.

  12. Biocatalytic Synthesis of Epoxy Resins from Fatty Acids as a Versatile Route for the Formation of Polymer Thermosets with Tunable Properties.

    Science.gov (United States)

    Torron, Susana; Semlitsch, Stefan; Martinelle, Mats; Johansson, Mats

    2016-12-12

    The work herein presented describes the synthesis and polymerization of series of bio-based epoxy resins prepared through lipase catalyzed transesterification. The epoxy-functional polyester resins with various architectures (linear, tri-branched, and tetra-branched) were synthesized through condensation of fatty acids derived from epoxidized soybean oil and linseed oil with three different hydroxyl cores under bulk conditions. The selectivity of the lipases toward esterification/transesterification reactions allowed the formation of macromers with up to 12 epoxides in the backbone. The high degree of functionality of the resins resulted in polymer thermosets with T g values ranging from -25 to over 100 °C prepared through cationic polymerization. The determining parameters of the synthesis and the mechanism for the formation of the species were determined through kinetic studies by 1 H NMR, SEC, and molecular modeling studies. The correlation between macromer structure and thermoset properties was studied through real-time FTIR measurements, DSC, and DMA.

  13. Biosynthesis of vitamin B12: Concerning the identity of the two-carbon fragment eliminated during anaerobic formation of cobyrinic acid

    Science.gov (United States)

    Wang, Jianji; Stolowich, Neal J.; Santander, Patricio J.; Park, Jeong Ho; Scott, A. Ian

    1996-01-01

    It has been proved that, during anaerobic biosynthesis of the corrin macrocycle, the two-carbon fragment excised from the precursor, precorrin-3, is acetaldehyde, which originates from C-20 and its attached methyl group. This apparently contradictory finding is rationalized in terms of the subsequent enzymatic oxidation of acetaldehyde to acetic acid, which was previously regarded as the volatile fragment released by the action of the biosynthetic enzymes of Propionibacterium shermanii. The observation that acetaldehyde (rather than acetic acid) is extruded during anaerobic B12 synthesis is in full accord with the structure of factor IV, a new intermediate on the pathway. PMID:8962048

  14. An Acidic pH is a determinant factor for TRI genes expression and trichothecenes B biosynthesis in Fusarium graminearum

    OpenAIRE

    2010-01-01

    Abstract Reducing production of trichothecene B by Fusarium graminearum on cereals is necessary to avoid contamination leading to yields reduction and having harmful impacts on human and animal health. Understanding how trichothecenes biosynthesis is induced is essential. Effect of ambient pH on fungal growth, toxin biosynthesis and TRI genes expression was studied during in vitro liquid culture of F. graminearum on minimal medium. Fungal development stopped at day 3 after a sharp ...

  15. Xanthophylls and abscisic acid biosynthesis in water-stressed bean leaves

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Walton, D.C.

    1987-12-01

    Experiments were designed to obtain evidence about the possible role of xanthophylls as abscisic acid (ABA) precursors in water-stressed leaves of Phaseolus vularis L. Leaves were exposed to /sup 14/CO/sub 2/ and the specific activities of several major leaf xanthophylls and stress-induced ABA were determined after a chase in /sup 12/CO/sub 2/ for varying periods of time. The ABA specific radioactivities were about 30 to 70% of that of lutein and violaxanthin regardless of the chase period. The specific activity of neoxanthin, however, was only about 15% of that of ABA. The effects of fluridone on xanthophyll and ABA levels and the extent of labeling of both from /sup 14/CO/sub 2/ were determined. Fluridone did not inhibit the accumulation of ABA when leaves were stressed once, although subsequent stresses in the presence of fluridone did lead to a reduced ABA accumulation. The incorporation of /sup 14/C from /sup 14/CO/sub 2/ into ABA and the xanthophylls was inhibited by fluridone and to about the same extent. The incorporation of /sup 18/O into ABA from violaxanthin which had been labeled in situ by means of the violaxanthin cycle was measured. The results indicated that a portion of the ABA accumulated during stress was formed from violaxanthin which had been labeled with /sup 18/O. The results of these experiments are consistent with a preformed xanthophyll(s) as the major ABA precursor in water-stressed bean leaves.

  16. High-titer biosynthesis of hyaluronic acid by recombinant Corynebacterium glutamicum.

    Science.gov (United States)

    Cheng, Fangyu; Gong, Qianying; Yu, Huimin; Stephanopoulos, Gregory

    2016-03-01

    Hyaluronic acid (HA) plays important roles in human tissue system, thus it is highly desirable for various applications, such as in medical, clinic and cosmetic fields. The wild microbial producer of HA, streptococcus, was restricted by its potential pathogens, hence different recombinant hosts are being explored. In this work, we engineered Corynebacterium glutamicum, a GRAS (Generally Recognized as Safe) organism free of exotoxins and endotoxins to produce HA with high titer and satisfied Mw . The ssehasA gene encoding hyaluronan synthase (HasA) was artificially synthesized with codon preference of C. glutamicum. Other genes involved in the HA synthetic pathway were directly cloned from the C. glutamicum genome. The operon structures and constitutive or inducible promoters were particularly compared and the preferred environmental conditions were also optimized. Using glucose and corn syrup powder as carbon and nitrogen sources, batch cultures of the engineered C.glutamicum with operon ssehasA-hasB driven by Ptac promoter were performed in a 5 L fermentor. The maximal HA titer, productivity and yield reached 8.3 g/L, 0.24 g/L/h and 0.22 gHA/gGlucose, respectively; meanwhile the maximal Mw was 1.30 MDa. This work provides a safe and efficient novel producer of HA with huge industrial prospects. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Biosynthesis of iminodiacetic acid from iminodiacetonitrile by immobilized recombinant Escherichia coli harboring nitrilase.

    Science.gov (United States)

    Liu, Zhi-Qiang; Zhou, Ming; Zhang, Xin-Hong; Xu, Jian-Miao; Xue, Ya-Ping; Zheng, Yu-Guo

    2012-01-01

    Iminodiacetic acid (IDA) is widely used as an intermediate in the manufacture of chelating agents, glyphosate herbicides and surfactants. In the current work, the fragment with the length of 1,110 bp encoding the Acidovorax facilis nitrilase was obtained. The recombinant nitrilase expressed in Escherichia coli BL21 (DE3) was successfully used in the production of IDA from iminodiacetonitrile. To improve the stability of operation, the recombinant cells were entrapped in polyvinyl alcohol (PVA) and sodium alginate (SA) copolymer. The maximum relative nitrilase activity with 98.1% was further observed at 1.0% SA, 8.0% PVA, 1.0% CaCl(2), and 5.0% wet cells, under conditions of 1.0% iminodiacetonitrile in distilled water and a temperature of 40°C, respectively. The entrapped cells facilitated easy separation and good recycling compared with free cells. Moreover, the immobilized cells showed good operation and storage stability. This report is the first to describe IDA preparation using immobilized recombinant E. coli harboring nitrilase. Copyright © 2012 S. Karger AG, Basel.

  18. Lactic Acid Bacteria and Their Bacteriocins: Classification, Biosynthesis and Applications against Uropathogens: A Mini-Review

    Directory of Open Access Journals (Sweden)

    Mduduzi Paul Mokoena

    2017-07-01

    Full Text Available Several lactic acid bacteria (LAB isolates from the Lactobacillus genera have been applied in food preservation, partly due to their antimicrobial properties. Their application in the control of human pathogens holds promise provided appropriate strains are scientifically chosen and a suitable mode of delivery is utilized. Urinary tract infection (UTI is a global problem, affecting mainly diabetic patients and women. Many uropathogens are developing resistance to commonly used antibiotics. There is a need for more research on the ability of LAB to inhibit uropathogens, with a view to apply them in clinical settings, while adhering to strict selection guidelines in the choice of candidate LAB. While several studies have indicated the ability of LAB to elicit inhibitory activities against uropathogens in vitro, more in vivo and clinical trials are essential to validate the efficacy of LAB in the treatment and prevention of UTI. The emerging applications of LAB such as in adjuvant therapy, oral vaccine development, and as purveyors of bioprotective agents, are relevant in infection prevention and amelioration. Therefore, this review explores the potential of LAB isolates and their bacteriocins to control uropathogens, with a view to limit clinical use of antibiotics.

  19. Minireview on Glutamine Synthetase Deficiency, an Ultra-Rare Inborn Error of Amino Acid Biosynthesis

    Directory of Open Access Journals (Sweden)

    Marta Spodenkiewicz

    2016-10-01

    Full Text Available Glutamine synthetase (GS is a cytosolic enzyme that produces glutamine, the most abundant free amino acid in the human body. Glutamine is a major substrate for various metabolic pathways, and is thus an important factor for the functioning of many organs; therefore, deficiency of glutamine due to a defect in GS is incompatible with normal life. Mutations in the human GLUL gene (encoding for GS can cause an ultra-rare recessive inborn error of metabolism—congenital glutamine synthetase deficiency. This disease was reported until now in only three unrelated patients, all of whom suffered from neonatal onset severe epileptic encephalopathy. The hallmark of GS deficiency in these patients was decreased levels of glutamine in body fluids, associated with chronic hyperammonemia. This review aims at recapitulating the clinical history of the three known patients with congenital GS deficiency and summarizes the findings from studies done along with the work-up of these patients. It is the aim of this paper to convince the reader that (i this disorder is possibly underdiagnosed, since decreased concentrations of metabolites do not receive the attention they deserve; and (ii early detection of GS deficiency may help to improve the outcome of patients who could be treated early with metabolites that are lacking in this condition.

  20. The impact of hydrofluoric acid etching followed by unfilled resin on the biaxial strength of a glass-ceramic.

    Science.gov (United States)

    Posritong, Sumana; Borges, Alexandre Luiz Souto; Chu, Tien-Min Gabriel; Eckert, George J; Bottino, Marco A; Bottino, Marco C

    2013-11-01

    To evaluate the null hypotheses that hydrofluoric (HF) acid etching time would neither decrease the biaxial flexural strength of a glass-based veneering ceramic nor enhance it after silane and unfilled resin (UR) applications. Disc-shaped IPS e.max ZirPress specimens were allocated into 12 groups: G1-control (no-etching), G2-30 s, G3-60 s, G4-90 s, G5-120 s, G6-60 s+60 s. Groups (G7-G12) were treated in the same fashion as G1-G6, but followed by silane and UR applications. Surface morphology and roughness (Ra and Rq) of the ceramics were assessed by means of scanning electron microscopy (SEM) and profilometry, respectively. Flexural strength was determined by biaxial testing. Data were analyzed by two-way ANOVA and the Sidak test (α=0.05). Weibull statistics were estimated and finite element analysis (FEA) was carried out to verify the stress concentration end areas of fracture. The interaction (etching time vs. surface treatment) was significant for Ra (p=0.008) and Rq (0.0075). Resin-treated groups presented significantly lower Ra and Rq than non-treated groups, except for the 60s group (pceramic microstructure and that the UR was able to penetrate into the irregularities. A significant effect of etching time (p=0.029) on flexural strength was seen. G7-G12 presented higher strength than G1-G6 (pceramic flexural strength. Moreover, the flexural strength could be enhanced after UR treatment. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Expression of Tropodithietic Acid Biosynthesis Is Controlled by a Novel Autoinducer▿ †

    Science.gov (United States)

    Geng, Haifeng; Belas, Robert

    2010-01-01

    The interactions between marine prokaryotic and eukaryotic microorganisms are crucial to many biological and biogeochemical processes in the oceans. Often the interactions are mutualistic, as in the symbiosis between phytoplankton, e.g., the dinoflagellate Pfiesteria piscicida and Silicibacter sp. TM1040, a member of the Roseobacter taxonomic lineage. It is hypothesized that an important component of this symbiosis is bacterial production of tropodithietic acid (TDA), a biologically active tropolone compound whose synthesis requires the expression of tdaABCDEF (tdaA-F), as well as six additional genes (cysI, malY, paaIJK, and tdaH). The factors controlling tda gene expression are not known, although growth in laboratory standing liquid cultures drastically increases TDA levels. In this report, we measured the transcription of tda genes to gain a greater understanding of the factors controlling their expression. While the expression of tdaAB was constitutive, tdaCDE and tdaF mRNA increased significantly (3.7- and 17.4-fold, respectively) when cells were grown in standing liquid broth compared to their levels with shaking liquid culturing. No transcription of tdaC was detected when a tdaCp::lacZ transcriptional fusion was placed in 11 of the 12 Tda− mutant backgrounds, with cysI being the sole exception. The expression of tdaC could be restored to 9 of the remaining 11 Tda− mutants—tdaA and tdaH failed to respond—by placing wild-type (Tda+) strains in close proximity or by supplying exogenous TDA to the mutant, suggesting that TDA induces tda gene expression. These results indicate that TDA acts as an autoinducer of its own synthesis and suggest that roseobacters may use TDA as a quorum signal. PMID:20601479

  2. Expression of tropodithietic acid biosynthesis is controlled by a novel autoinducer.

    Science.gov (United States)

    Geng, Haifeng; Belas, Robert

    2010-09-01

    The interactions between marine prokaryotic and eukaryotic microorganisms are crucial to many biological and biogeochemical processes in the oceans. Often the interactions are mutualistic, as in the symbiosis between phytoplankton, e.g., the dinoflagellate Pfiesteria piscicida and Silicibacter sp. TM1040, a member of the Roseobacter taxonomic lineage. It is hypothesized that an important component of this symbiosis is bacterial production of tropodithietic acid (TDA), a biologically active tropolone compound whose synthesis requires the expression of tdaABCDEF (tdaA-F), as well as six additional genes (cysI, malY, paaIJK, and tdaH). The factors controlling tda gene expression are not known, although growth in laboratory standing liquid cultures drastically increases TDA levels. In this report, we measured the transcription of tda genes to gain a greater understanding of the factors controlling their expression. While the expression of tdaAB was constitutive, tdaCDE and tdaF mRNA increased significantly (3.7- and 17.4-fold, respectively) when cells were grown in standing liquid broth compared to their levels with shaking liquid culturing. No transcription of tdaC was detected when a tdaCp::lacZ transcriptional fusion was placed in 11 of the 12 Tda(-) mutant backgrounds, with cysI being the sole exception. The expression of tdaC could be restored to 9 of the remaining 11 Tda(-) mutants-tdaA and tdaH failed to respond-by placing wild-type (Tda(+)) strains in close proximity or by supplying exogenous TDA to the mutant, suggesting that TDA induces tda gene expression. These results indicate that TDA acts as an autoinducer of its own synthesis and suggest that roseobacters may use TDA as a quorum signal.

  3. Biosynthesis and thermal properties of PHBV produced from levulinic acid by Ralstonia eutropha.

    Directory of Open Access Journals (Sweden)

    Yuanpeng Wang

    Full Text Available Levulinic acid (LA can be cost-effectively produced from a vast array of renewable carbohydrate-containing biomaterials. LA could facilitate the commercialization of the polymer poly(hydroxybutyrate-co-hydroxyvalerate (PHBV and PHBV-based products as carbon substrates. Therefore, this paper focused on the production of PHBV by Ralstonia eutropha with LA for hydroxyvalerate (HV production, which plays an important role in enhancing the thermal properties of PHBV. Accordingly, the HV content of PHBV varied from 0-40.9% at different concentrations of LA. Stimulation of cell growth and PHBV accumulation were observed when 2-6 g L(-1 LA was supplied to the culture. The optimal nitrogen sources were determined to be 0.5 g L(-1 ammonium chloride and 2 g L(-1 casein peptone. It was determined that the optimal pH for cell growth and PHBV accumulation was 7.0. When the cultivation was performed in large scale (2 L fermenter with a low DO concentration of 30% and a pH of 7.0, a high maximum dry cell weight of 15.53 g L(-1 with a PHBV concentration of 12.61 g L(-1 (53.9% HV, up to 81.2% of the dry cell weight, was obtained. The melting point of PHBV found to be decreased as the fraction of HV present in the polymer increased, which resulted in an improvement in the ductility and flexibility of the polymer. The results of this study will improve the understanding of the PHBV accumulation and production by R. eutropha and will be valuable for the industrial production of biosynthesized polymers.

  4. Biosynthesis and thermal properties of PHBV produced from levulinic acid by Ralstonia eutropha.

    Science.gov (United States)

    Wang, Yuanpeng; Chen, Ronghui; Cai, JiYuan; Liu, Zhenggui; Zheng, Yanmei; Wang, Haitao; Li, Qingbiao; He, Ning

    2013-01-01

    Levulinic acid (LA) can be cost-effectively produced from a vast array of renewable carbohydrate-containing biomaterials. LA could facilitate the commercialization of the polymer poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and PHBV-based products as carbon substrates. Therefore, this paper focused on the production of PHBV by Ralstonia eutropha with LA for hydroxyvalerate (HV) production, which plays an important role in enhancing the thermal properties of PHBV. Accordingly, the HV content of PHBV varied from 0-40.9% at different concentrations of LA. Stimulation of cell growth and PHBV accumulation were observed when 2-6 g L(-1) LA was supplied to the culture. The optimal nitrogen sources were determined to be 0.5 g L(-1) ammonium chloride and 2 g L(-1) casein peptone. It was determined that the optimal pH for cell growth and PHBV accumulation was 7.0. When the cultivation was performed in large scale (2 L fermenter) with a low DO concentration of 30% and a pH of 7.0, a high maximum dry cell weight of 15.53 g L(-1) with a PHBV concentration of 12.61 g L(-1) (53.9% HV), up to 81.2% of the dry cell weight, was obtained. The melting point of PHBV found to be decreased as the fraction of HV present in the polymer increased, which resulted in an improvement in the ductility and flexibility of the polymer. The results of this study will improve the understanding of the PHBV accumulation and production by R. eutropha and will be valuable for the industrial production of biosynthesized polymers.

  5. Identification of a malonyl CoA-acyl carrier protein transacylase and its regulatory role in fatty acid biosynthesis in oleaginous microalga Nannochloropsis oceanica.

    Science.gov (United States)

    Chen, Jia-Wen; Liu, Wan-Jun; Hu, Dong-Xiong; Wang, Xiang; Balamurugan, Srinivasan; Alimujiang, Adili; Yang, Wei-Dong; Liu, Jie-Sheng; Li, Hong-Ye

    2017-09-01

    Oleaginous microalgae hold great promises for biofuel production. However, commercialization of microalgal biofuels remains impracticable due to the lack of suitable industrial strains with high growth rate and lipid productivity. Engineering of metabolic pathways is a potential strategy for the improvement of microalgal strains for the production of lipids and also value-added products in microalgae. Malonyl CoA-acyl carrier protein transacylase (MCAT) has been reported to be involved in fatty acid biosynthesis. Here, we identified a putative MCAT in the oleaginous marine microalga Nannochloropsis oceanica. NoMCAT overexpressing N. oceanica showed a higher growth rate and photosynthetic efficiency. The neutral lipid content of engineered lines showed a significant increase by up to 31% compared to wild type. Gas chromatography-mass spectrometry analysis revealed that NoMCAT overexpression significantly altered the fatty acid composition. The composition of eicosapentaenoic acid (C20:5), which is a polyunsaturated fatty acid necessary for animal nutrition, increased by 8%. These results demonstrate the role of MCAT in enhancing fatty acid biosynthesis and growth in microalgae, and also provide an insight into metabolic engineering of microalgae with high industrial potential. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  6. Improvement of Neutral Lipid and Polyunsaturated Fatty Acid Biosynthesis by Overexpressing a Type 2 Diacylglycerol Acyltransferase in Marine Diatom Phaeodactylum tricornutum

    Directory of Open Access Journals (Sweden)

    Ying-Fang Niu

    2013-11-01

    Full Text Available Microalgae have been emerging as an important source for the production of bioactive compounds. Marine diatoms can store high amounts of lipid and grow quite quickly. However, the genetic and biochemical characteristics of fatty acid biosynthesis in diatoms remain unclear. Glycerophospholipids are integral as structural and functional components of cellular membranes, as well as precursors of various lipid mediators. In addition, diacylglycerol acyltransferase (DGAT is a key enzyme that catalyzes the last step of triacylglyceride (TAG biosynthesis. However, a comprehensive sequence-structure and functional analysis of DGAT in diatoms is lacking. In this study, an isoform of diacylglycerol acyltransferase type 2 of the marine diatom Phaeodactylum tricornutum was characterized. Surprisingly, DGAT2 overexpression in P. tricornutum stimulated more oil bodies, and the neutral lipid content increased by 35%. The fatty acid composition showed a significant increase in the proportion of polyunsaturated fatty acids; in particular, EPA was increased by 76.2%. Moreover, the growth rate of transgenic microalgae remained similar, thereby maintaining a high biomass. Our results suggest that increased DGAT2 expression could alter fatty acid profile in the diatom, and the results thus represent a valuable strategy for polyunsaturated fatty acid production by genetic manipulation.

  7. High-level production of Arthrobacter aurescens CYC705 nitrilase in Escherichia coli for biosynthesis of iminodiacetic acid.

    Science.gov (United States)

    Su, Erzheng; Lu, Chao; Ma, Xiaoqiang; Cai, Wenwen; Zhu, Shujing

    2016-07-01

    Nitrilase from Arthrobacter aurescens CYC705 can hydrolyze the iminodiacetonitrile to iminodiacetic acid (IDA) efficiently, and its high-level production in Escherichia coli has not been established. In the present work, the production of this nitrilase expressed in E. coli BL21(DE3) with a recombinant plasmid pET28a-cyc705 was optimized. Various culture conditions and process parameters including medium components and concentrations, inducer types and concentrations, inducing temperature and time were systematically examined in a shake flask. After optimization, the OD600 , nitrilase activity, and productivity were obviously improved and achieved to 40.91 ± 1.341, 98.12 ± 1.248 U/mL, and 2,230 ± 28.36 U L(-1)  H(-1) , respectively, about 2.1-, 30-, and 33-fold increases as compared with those in the primary medium. Furthermore, four different fermentation strategies were adopted to scale up cultivation of the recombinant E. coli BL21(DE3)/pET28a-cyc705 in a 3.7-L fermenter. Substituting the peanut powder with fish peptone and accompanying with 1.0% glycerol feeding could significantly reduce the bubble production and shorten the fermentation time, which resulted in a nitrilase productivity of 4,653 ± 38.16 U L(-1) H(-1) that was about two times higher than that in a shake flask. The high-level production of A. aurescens CYC705 nitrilase established in this study will meet the need of industrial biosynthesis of IDA. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

  8. Mitochondrial oxidative stress alters a pathway in Caenorhabditis elegans strongly resembling that of bile acid biosynthesis and secretion in vertebrates.

    Directory of Open Access Journals (Sweden)

    Ju-Ling Liu

    Full Text Available Mammalian bile acids (BAs are oxidized metabolites of cholesterol whose amphiphilic properties serve in lipid and cholesterol uptake. BAs also act as hormone-like substances that regulate metabolism. The Caenorhabditis elegans clk-1 mutants sustain elevated mitochondrial oxidative stress and display a slow defecation phenotype that is sensitive to the level of dietary cholesterol. We found that: 1 The defecation phenotype of clk-1 mutants is suppressed by mutations in tat-2 identified in a previous unbiased screen for suppressors of clk-1. TAT-2 is homologous to ATP8B1, a flippase required for normal BA secretion in mammals. 2 The phenotype is suppressed by cholestyramine, a resin that binds BAs. 3 The phenotype is suppressed by the knock-down of C. elegans homologues of BA-biosynthetic enzymes. 4 The phenotype is enhanced by treatment with BAs. 5 Lipid extracts from C. elegans contain an activity that mimics the effect of BAs on clk-1, and the activity is more abundant in clk-1 extracts. 6 clk-1 and clk-1;tat-2 double mutants show altered cholesterol content. 7 The clk-1 phenotype is enhanced by high dietary cholesterol and this requires TAT-2. 8 Suppression of clk-1 by tat-2 is rescued by BAs, and this requires dietary cholesterol. 9 The clk-1 phenotype, including the level of activity in lipid extracts, is suppressed by antioxidants and enhanced by depletion of mitochondrial superoxide dismutases. These observations suggest that C. elegans synthesizes and secretes molecules with properties and functions resembling those of BAs. These molecules act in cholesterol uptake, and their level of synthesis is up-regulated by mitochondrial oxidative stress. Future investigations should reveal whether these molecules are in fact BAs, which would suggest the unexplored possibility that the elevated oxidative stress that characterizes the metabolic syndrome might participate in disease processes by affecting the regulation of metabolism by BAs.

  9. The putative E3 ubiquitin ligase ECERIFERUM9 regulates abscisic acid biosynthesis and response during seed germination and postgermination growth in arabidopsis

    KAUST Repository

    Zhao, Huayan

    2014-05-08

    The ECERIFERUM9 (CER9) gene encodes a putative E3 ubiquitin ligase that functions in cuticle biosynthesis and the maintenance of plant water status. Here, we found that CER9 is also involved in abscisic acid (ABA) signaling in seeds and young seedlings of Arabidopsis (Arabidopsis thaliana). The germinated embryos of the mutants exhibited enhanced sensitivity to ABA during the transition from reversible dormancy to determinate seedling growth. Expression of the CER9 gene is closely related to ABA levels and displays a similar pattern to that of ABSCISIC ACID-INSENSITIVE5 (ABI5), which encodes a positive regulator of ABA responses in seeds. cer9 mutant seeds exhibited delayed germination that is independent of seed coat permeability. Quantitative proteomic analyses showed that cer9 seeds had a protein profile similar to that of the wild type treated with ABA. Transcriptomics analyses revealed that genes involved in ABA biosynthesis or signaling pathways were differentially regulated in cer9 seeds. Consistent with this, high levels of ABA were detected in dry seeds of cer9. Blocking ABA biosynthesis by fluridone treatment or by combining an ABA-deficient mutation with cer9 attenuated the phenotypes of cer9. Whereas introduction of the abi1-1, abi3-1, or abi4-103 mutation could completely eliminate the ABA hypersensitivity of cer9, introduction of abi5 resulted only in partial suppression. These results indicate that CER9 is a novel negative regulator of ABA biosynthesis and the ABA signaling pathway during seed germination. © 2014 American Society of Plant Biologists. All Rights Reserved.

  10. High Performance Fatty Acid-Based Vinyl Ester Resin for Liquid Molding

    National Research Council Canada - National Science Library

    Geng, Xing; La Scala, John J; Sands, James M; Palmese, Guiseppe R

    2007-01-01

    ...% compared to 40-60 wt% associated with commercial products. In addition, fatty acid-based monomers can bring about other benefits like higher toughness, lower exothermal heat and low volume shrinkage...

  11. Selective sorption of ruthenium from acidic medium by Amberlite XAD 7 resin impregnated with iodide salt of N,N'-diisobutyl(α-Trialkylammonium)-acetamide

    International Nuclear Information System (INIS)

    Sharma, Shikha; Ghosh, Sunil K.; Sharma, J.N.

    2015-01-01

    This work investigates the removal of ruthenium (III) from aqueous nitric acid solutions using solvent impregnated resin (SIR). The SIR has been made by impregnating Amberlite XAD-7 with iodide salt of N,N'-diisobutyl(α-trialkylammonium)acetamide as the extractant and methanol as the solvent by a wet impregnation technique. This solvent has already been successfully investigated by us for selective extraction of ruthenium (III) from nitric acid solution by solvent extraction technique. Maximum loading of ammonium acetamide on Amberlite XAD was found to be in the ratio of 1:2. Loaded resin was characterized by IR and SEM analyses. The effect of metal ion concentration on the sorption of ruthenium (III) ions has been investigated to quantify the sorption capacity of resin for Ru. Maximum loading of ruthenium was found to be 14 mg/g of resin. Maximum K d obtained was 754. Ruthenium was successfully stripped from SIR using sodium hydroxide solution in a single contact. (author)

  12. Preparation and characterization of anion exchange resin decorated with magnetite nanoparticles for removal of p-toluic acid from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Davarpanah, Morteza, E-mail: Davarpanah.morteza@gmail.com; Ahmadpour, Ali; Rohani Bastami, Tahereh

    2015-02-01

    Polystyrene resin was covalently functionalized with diethanolamine and then decorated with magnetite nanoparticles by a novel and simple co-precipitation method using iron(II) sulfate as precursor. The products were characterized by Fourier transform infrared spectroscopy, elemental analysis, X-ray diffraction, Mössbauer spectroscopy, field-emission scanning electron microscopy and vibrating sample magnetometer. Adsorption of p-toluic acid (p-TA) onto magnetite-decorated polystyrene (MAG-PS) was studied and compared with that of diethanolamine-functionalized polystyrene and a commercial anion exchange resin. Results showed that the magnetite nanoparticles with an average size of 20.4 nm were successfully formed on the surface of polystyrene resin, and MAG-PS was exhibited high affinity for the removal of p-TA. - Highlights: • .Polystyrene resin was covalently functionalized with diethanolamine. • .The functionalized adsorbents were decorated with magnetite nanoparticles (∼20 nm). • .Proposed magnetization procedure was high-efficient and relatively simple. • .Magnetic adsorbent was presented high affinity for removal of p-toluic acid.

  13. Modification of membrane properties and fatty acids biosynthesis-related genes in Escherichia coli and Staphylococcus aureus: Implications for the antibacterial mechanism of naringenin.

    Science.gov (United States)

    Wang, Lang-Hong; Zeng, Xin-An; Wang, Man-Sheng; Brennan, Charles S; Gong, Deming

    2018-02-01

    In this work, modifications of cell membrane fluidity, fatty acid composition and fatty acid biosynthesis-associated genes of Escherichia coli ATCC 25922 (E. coli) and Staphylococcus aureus ATCC 6538 (S. aureus), during growth in the presence of naringenin (NAR), one of the natural antibacterial components in citrus plants, was investigated. Compared to E. coli, the growth of S. aureus was significantly inhibited by NAR in low concentrations. Combination of gas chromatography-mass spectrometry with fluorescence polarization analysis revealed that E. coli and S. aureus cells increased membrane fluidity by altering the composition of membrane fatty acids after exposure to NAR. For example, E. coli cells produced more unsaturated fatty acids (from 18.5% to 43.3%) at the expense of both cyclopropane and saturated fatty acids after growth in the concentrations of NAR from 0 to 2.20mM. For S. aureus grown with NAR at 0 to 1.47mM, the relative proportions of anteiso-branched chain fatty acids increased from 37.2% to 54.4%, whereas iso-branched and straight chain fatty acids decreased from 30.0% and 33.1% to 21.6% and 23.7%, respectively. Real time q-PCR analysis showed that NAR at higher concentrations induced a significant down-regulation of fatty acid biosynthesis-associated genes in the bacteria, with the exception of an increased expression of fabA gene. The minimum inhibitory concentration (MIC) of NAR against these two bacteria was determined, and both of bacteria underwent morphological changes after exposure to 1.0 and 2.0 MIC. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Acetic acid acts as an elicitor exerting a chitosan-like effect on xanthone biosynthesis in Hypericum perforatum L. root cultures.

    Science.gov (United States)

    Valletta, Alessio; De Angelis, Giulia; Badiali, Camilla; Brasili, Elisa; Miccheli, Alfredo; Di Cocco, Maria Enrica; Pasqua, Gabriella

    2016-05-01

    Acetic acid acts as a signal molecule, strongly enhancing xanthone biosynthesis in Hypericum perforatum root cultures. This activity is specific, as demonstrated by the comparison with other short-chain monocarboxylic acids. We have recently demonstrated that Hypericum perforatum root cultures constitutively produce xanthones at higher levels than the root of the plant and that they respond to chitosan (CHIT) elicitation with a noteworthy increase in xanthone production. In the present study, CHIT was administered to H. perforatum root cultures using three different elicitation protocols, and the increase in xanthone production was evaluated. The best results (550 % xanthone increase) were obtained by subjecting the roots to a single elicitation with 200 mg l(-1) CHIT and maintaining the elicitor in the culture medium for 7 days. To discriminate the effect of CHIT from that of the solvent, control experiments were performed by administering AcOH alone at the same concentration used for CHIT solubilization. Unexpectedly, AcOH caused an increase in xanthone production comparable to that observed in response to CHIT. Feeding experiments with (13)C-labeled AcOH demonstrated that this compound was not incorporated into the xanthone skeleton. Other short-chain monocarboxylic acids (i.e., propionic and butyric acid) have little or no effect on the production of xanthones. These results indicate that AcOH acts as a specific signal molecule, able to greatly enhance xanthone biosynthesis in H. perforatum root cultures.

  15. Ion-exclusion chromatographic behavior of aliphatic carboxylic acids and benzenecarboxylic acids on a sulfonated styrene--divinylbenzene co-polymer resin column with sulfuric acid containing various alcohols as eluent.

    Science.gov (United States)

    Ohta, Kazutoku; Towata, Atsuya; Ohashi, Masayoshi

    2003-05-16

    The addition of C1-C7 alcohols (methanol, ethanol, propanol, butanol, heptanol, hexanol and heptanol) to dilute sulfuric acid as eluent in ion-exclusion chromatography using a highly sulfonated styrene-divinylbenzene co-polymer resin (TSKgel SCX) in the H+ form as the stationary phase was carried out for the simultaneous separations of both (a) C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, 2-methylvaleric, isocaproic, caproic, 2,2-dimethyl-n-valeric, 2-methylhexanoic, 5-methylhexanoic and heptanoic acids) and (b) benzenecarboxylic acids (pyromellitic, hemimellitic, trimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic and salicylic acids and phenol). Heptanol was the most effective modifier in ion-exclusion chromatography for the improvement of peak shapes and a reduction in retention volumes for higher aliphatic carboxylic acids and benzenecarboxylic acids. Excellent simultaneous separation and relatively highly sensitive conductimetric detection for these C1-C7 aliphatic carboxylic acids were achieved on the TSKgel SCX column (150 x 6 mm I.D.) in 30 min using 0.5 mM sulfuric acid containing 0.025% heptanol as eluent. Excellent simultaneous separation and highly sensitive UV detection at 200 nm for these benzenecarboxylic acids were also achieved on the TSKgel SCX column in 30 min using 5 mM sulfuric acid containing 0.075% heptanol as eluent.

  16. Glucose-lowering effects and mechanisms of the bile acid-sequestering resin sevelamer

    DEFF Research Database (Denmark)

    Brønden, Andreas; Mikkelsen, Kristian; Sonne, David P

    2018-01-01

    and mechanism(s) of sevelamer in patients with type 2 diabetes. MATERIALS AND METHODS: In this double-blinded randomized controlled trial, we randomized 30 patients with type 2 diabetes to sevelamer (n=20) or placebo (n=10). Participants were subjected to standardized 4-hour liquid meal tests at baseline...... synthesis of bile acids, a shift towards a more hydrophilic bile acid pool and increased lipogenesis. No glucagon-like peptide-1-mediated effects on insulin, glucagon or gastric emptying were evident, which point to limited contribution of this incretin hormone to the glucose-lowering effect of sevelamer...

  17. Enhanced root growth in phosphate-starved Arabidopsis by stimulating de novo phospholipid biosynthesis through the overexpression of LYSOPHOSPHATIDIC ACID ACYLTRANSFERASE 2 (LPAT2).

    Science.gov (United States)

    Angkawijaya, Artik Elisa; Nguyen, Van Cam; Nakamura, Yuki

    2017-09-01

    Upon phosphate starvation, plants retard shoot growth but promote root development presumably to enhance phosphate assimilation from the ground. Membrane lipid remodelling is a metabolic adaptation that replaces membrane phospholipids by non-phosphorous galactolipids, thereby allowing plants to obtain scarce phosphate yet maintain the membrane structure. However, stoichiometry of this phospholipid-to-galactolipid conversion may not account for the massive demand of membrane lipids that enables active growth of roots under phosphate starvation, thereby suggesting the involvement of de novo phospholipid biosynthesis, which is not represented in the current model. We overexpressed an endoplasmic reticulum-localized lysophosphatidic acid acyltransferase, LPAT2, a key enzyme that catalyses the last step of de novo phospholipid biosynthesis. Two independent LPAT2 overexpression lines showed no visible phenotype under normal conditions but showed increased root length under phosphate starvation, with no effect on phosphate starvation response including marker gene expression, root hair development and anthocyanin accumulation. Accompanying membrane glycerolipid profiling of LPAT2-overexpressing plants revealed an increased content of major phospholipid classes and distinct responses to phosphate starvation between shoot and root. The findings propose a revised model of membrane lipid remodelling, in which de novo phospholipid biosynthesis mediated by LPAT2 contributes significantly to root development under phosphate starvation. © 2017 John Wiley & Sons Ltd.

  18. Parthenolide accumulation and expression of genes related to parthenolide biosynthesis affected by exogenous application of methyl jasmonate and salicylic acid in Tanacetum parthenium.

    Science.gov (United States)

    Majdi, Mohammad; Abdollahi, Mohammad Reza; Maroufi, Asad

    2015-11-01

    Up-regulation of germacrene A synthase and down-regulation of parthenolide hydroxylase genes play key role in parthenolide accumulation of feverfew plants treated with methyl jasmonate and salicylic acid. Parthenolide is an important sesquiterpene lactone due to its anti-migraine and anti-cancer properties. Parthenolide amount was quantified by high-performance liquid chromatography after foliar application of methyl jasmonate (100 µM) or salicylic acid (1.0 mM) on feverfew leaves in time course experiment (3-96 h). Results indicate that exogenous application of methyl jasmonate or salicylic acid activated parthenolide biosynthesis. Parthenolide content reached its highest amount at 24 h after methyl jasmonate or salicylic acid treatments, which were 3.1- and 1.96-fold higher than control plants, respectively. Parthenolide transiently increased due to methyl jasmonate or salicylic acid treatments until 24 h, but did not show significant difference compared with control plants at 48 and 96 h time points in both treatments. Also, the transcript levels of early pathway (upstream) genes of terpene biosynthesis including 3-hydroxy-3-methylglutaryl-coenzyme A reductase, 1-deoxy-D-xylulose-5-phosphate reductoisomerase and hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase and the biosynthetic genes of parthenolide including germacrene A synthase, germacrene A oxidase, costunolide synthase and parthenolide synthase were increased by methyl jasmonate and salicylic acid treatments, but with different intensity. The transcriptional levels of these genes were higher in methyl jasmonate-treated plants than salicylic acid-treated plants. Parthenolide content measurements along with expression pattern analysis of the aforementioned genes and parthenolide hydroxylase as side branch gene of parthenolide suggest that the expression patterns of early pathway genes were not directly consistent with parthenolide accumulation pattern; hence, parthenolide accumulation is

  19. Antisense-mediated suppression of C-hordein biosynthesis in the barley grain results in correlated changes in the transcriptome, protein profile, and amino acid composition

    DEFF Research Database (Denmark)

    Hansen, Mette; Lange, Marianne; Friis, Carsten

    2007-01-01

    Antisense- or RNAi-mediated suppression of the biosynthesis of nutritionally inferior storage proteins is a promising strategy for improving the amino acid profile of seeds. However, the potential pleiotropic effects of this on interconnected pathways and the agronomic quality traits need...... to be addressed. In the current study, a transcriptomic analysis of an antisense C-hordein line of barley was performed, using a grain-specific cDNA array. The C-hordein antisense line is characterized by marked changes in storage protein and amino acid profiles, while the seed weight is within the normal range...... and no external morphological irregularities were observed. The results of the transcriptome analysis showed excellent correlation with data on changes in the relative proportions of storage proteins and amino acid composition. The antisense line had a lower C-hordein level and down-regulated transcript encoding...

  20. The Arabidopsis YUCCA1 Flavin Monooxygenase Functions in the Indole-3-Pyruvic Acid Branch of Auxin Biosynthesis

    Czech Academy of Sciences Publication Activity Database

    Stepanova, A.N.; Yun, J.; Robles, L.M.; Novák, Ondřej; He, W.; Guo, H.W.; Ljung, K.; Alonso, J.M.

    2011-01-01

    Roč. 23, č. 11 (2011), s. 3961-3973 ISSN 1040-4651 R&D Projects: GA ČR GA301/08/1649 Keywords : PLANT DEVELOPMENT * GLUCOSINOLATE BIOSYNTHESIS * REPRODUCTIVE DEVELOPMENT * MASS-SPECTROMETRY * ALDEHYDE OXIDASE * THALIANA * GENE * METABOLISM * MUTANTS * PATHWAY Subject RIV: EF - Botanics Impact factor: 8.987, year: 2011

  1. Heat Stress Modulates Mycelium Growth, Heat Shock Protein Expression, Ganoderic Acid Biosynthesis, and Hyphal Branching of Ganoderma lucidum via Cytosolic Ca2.

    Science.gov (United States)

    Zhang, Xue; Ren, Ang; Li, Meng-Jiao; Cao, Peng-Fei; Chen, Tian-Xi; Zhang, Guang; Shi, Liang; Jiang, Ai-Liang; Zhao, Ming-Wen

    2016-07-15

    Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum Our data showed that HS induced a significant increase in cytosolic Ca(2+) concentration. Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research offers a new

  2. Heat Stress Modulates Mycelium Growth, Heat Shock Protein Expression, Ganoderic Acid Biosynthesis, and Hyphal Branching of Ganoderma lucidum via Cytosolic Ca2+

    Science.gov (United States)

    Zhang, Xue; Ren, Ang; Li, Meng-Jiao; Cao, Peng-Fei; Chen, Tian-Xi; Zhang, Guang; Shi, Liang; Jiang, Ai-Liang

    2016-01-01

    ABSTRACT Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum. Our data showed that HS induced a significant increase in cytosolic Ca2+ concentration. Further evidence showed that Ca2+ might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca2+ participates in heat shock signal transduction and regulates downstream events in filamentous fungi. IMPORTANCE Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum. Further evidence showed that Ca2+ might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca2+ participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research

  3. AP2/ERF Transcription Factor, Ii049, Positively Regulates Lignan Biosynthesis in Isatis indigotica through Activating Salicylic Acid Signaling and Lignan/Lignin Pathway Genes

    Directory of Open Access Journals (Sweden)

    Ruifang Ma

    2017-08-01

    Full Text Available Lignans, such as lariciresinol and its derivatives, have been identified as effective antiviral ingredients in Isatis indigotica. Evidence suggests that the APETALA2/ethylene response factor (AP2/ERF family might be related to the biosynthesis of lignans in I. indigotica. However, the special role played by the AP2/ERF family in the metabolism and its underlying putative mechanism still need to be elucidated. One novel AP2/ERF gene, named Ii049, was isolated and characterized from I. indigotica in this study. The quantitative real-time PCR analysis revealed that Ii049 was expressed highest in the root and responded to methyl jasmonate, salicylic acid (SA and abscisic acid treatments to various degrees. Subcellular localization analysis indicated that Ii049 protein was localized in the nucleus. Knocking-down the expression of Ii049 caused a remarkable reduction of lignan/lignin contents and transcript levels of genes involved in the lignan/lignin biosynthetic pathway. Ii049 bound to the coupled element 1, RAV1AAT and CRTAREHVCBF2 motifs of genes IiPAL and IiCCR, the key structural genes in the lignan/lignin pathway. Furthermore, Ii049 was also essential for SA biosynthesis, and SA induced lignan accumulation in I. indigotica. Notably, the transgenic I. indigotica hairy roots overexpressing Ii049 showed high expression levels of lignan/lignin biosynthetic genes and SA content, resulting in significant accumulation of lignan/lignin. The best-engineered line (OVX049-10 produced 425.60 μg·g−1 lariciresinol, an 8.3-fold increase compared with the wild type production. This study revealed the function of Ii049 in regulating lignan/lignin biosynthesis, which had the potential to increase the content of valuable lignan/lignin in economically significant medicinal plants.

  4. Glutathione biosynthesis and activity of dependent enzymes in food grade lactic acid bacteria harboring multidomain bifunctional fusion gene (gshF).

    Science.gov (United States)

    Pophaly, Sarang Dilip; Poonam; Pophaly, Saurabh Dilip; Kapila, Suman; Nanda, Dhiraj Kumar; Tomar, Sudhir Kumar; Singh, Rameshwar

    2017-04-12

    To assess glutathione (GSH) biosynthesis ability and activity of dependent enzymes in food grade lactic acid bacteria and correlating with genomic information on glutathione system in LAB. Whole genome sequences of twenty-six food grade LAB were screened for presence/absence of set of genes involved in de novo glutathione system. Multiple strains of S. thermophilus (37), Lb. casei (37), Lb. rhamnosus (4), Lb. paracasei (8) Lb. plantarum (23) & Lb. fermentum (22) were screened for biochemical evidence of GSH system. Multiple sequence analysis of GshF sequences was carried out for comparing the genomic signatures between GSH producing and non-producing species. Streptococcus thermophilus was found to have de novo glutathione biosynthesis as well as import ability. Lactobacillus spp. were negative for GSH synthesis but could import it from the medium. All the species exhibited prolific glutathione reductase and peroxidase activity. Sequence analysis revealed absence of key amino acid residues as well as a truncated N-terminal region in lactobacilli. The study provides a comprehensive view on status of an important antioxidative system (the glutathione system) in LAB and is expected to serve as a primer for future work on mechanistic role of GSH in the group. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  5. Characterization of Indole-3-acetic Acid Biosynthesis and the Effects of This Phytohormone on the Proteome of the Plant-Associated Microbe Pantoea sp. YR343.

    Science.gov (United States)

    Estenson, Kasey; Hurst, Gregory B; Standaert, Robert F; Bible, Amber N; Garcia, David; Chourey, Karuna; Doktycz, Mitchel J; Morrell-Falvey, Jennifer L

    2018-04-06

    Indole-3-acetic acid (IAA) plays a central role in plant growth and development, and many plant-associated microbes produce IAA using tryptophan as the precursor. Using genomic analyses, we predicted that Pantoea sp. YR343, a microbe isolated from Populus deltoides, synthesizes IAA using the indole-3-pyruvate (IPA) pathway. To better understand IAA biosynthesis and the effects of IAA exposure on cell physiology, we characterized proteomes of Pantoea sp. YR343 grown in the presence of tryptophan or IAA. Exposure to IAA resulted in upregulation of proteins predicted to function in carbohydrate and amino acid transport and exopolysaccharide (EPS) biosynthesis. Metabolite profiles of wild-type cells showed the production of IPA, IAA, and tryptophol, consistent with an active IPA pathway. Finally, we constructed an Δ ipdC mutant that showed the elimination of tryptophol, consistent with a loss of IpdC activity, but was still able to produce IAA (20% of wild-type levels). Although we failed to detect intermediates from other known IAA biosynthetic pathways, this result suggests the possibility of an alternate pathway or the production of IAA by a nonenzymatic route in Pantoea sp. YR343. The Δ ipdC mutant was able to efficiently colonize poplar, suggesting that an active IPA pathway is not required for plant association.

  6. Biosynthesis of Antroquinonol and 4-Acetylantroquinonol B via a Polyketide Pathway Using Orsellinic Acid as a Ring Precursor in Antrodia cinnamomea.

    Science.gov (United States)

    Chou, Kevin Chi-Chung; Yang, Shang-Han; Wu, Hsiang-Lin; Lin, Pei-Yin; Chang, Tsu-Liang; Sheu, Fuu; Chen, Kai-Hsien; Chiang, Been-Huang

    2017-01-11

    Antroquinonol (AQ) and 4-acetylantroquinonol B (4-AAQB), isolated from the mycelium of Antrodia cinnamomea, have a similar chemical backbone to coenzyme Q (CoQ). Based on the postulation that biosynthesis of both AQ and 4-AAQB in A. cinnamomea starts from the polyketide pathway, we cultivated this fungus in a culture medium containing [U- 13 C]oleic acid, and then we analyzed the crude extracts of the mycelium using UHPLC-MS. We found that AQ and 4-AAQB follow similar biosynthetic sequences as CoQ. Obvious [ 13 C 2 ] fragments on the ring backbone were detected in the mass spectrum for [ 13 C 2 ]AQ, [ 13 C 2 ]4-AAQB, and their [ 13 C 2 ] intermediates found in this study. The orsellinic acid, formed from acetyl-CoA and malonyl-CoA via the polyketide pathway, was found to be a novel benzoquinone ring precursor for AQ and 4-AAQB. The identification of endogenously synthesized farnesylated intermediates allows us to postulate the routes of AQ and 4-AAQB biosynthesis in A. cinnamomea.

  7. The role of ß-ketoacyl-acyl carrier protein synthase III in the condensation steps of fatty acid biosynthesis in sunflower

    DEFF Research Database (Denmark)

    González-Mellado, Damián; von Wettstein, Penny; Garcés, Rafael

    2010-01-01

    seeds, a cDNA coding for HaKAS III (EF514400) was isolated, cloned and sequenced. Its protein sequence is as much as 72% identical to other KAS III-like ones such as those from Perilla frutescens, Jatropha curcas, Ricinus communis or Cuphea hookeriana. Phylogenetic study of the HaKAS III homologous......The ß-ketoacyl-acyl carrier protein synthase III (KAS III; EC 2.3.1.180) is a condensing enzyme catalyzing the initial step of fatty acid biosynthesis using acetyl-CoA as primer. To determine the mechanisms involved in the biosynthesis of fatty acids in sunflower (Helianthus annuus L.) developing...... proteins infers its origin from cyanobacterial ancestors. A genomic DNA gel blot analysis revealed that HaKAS III is a single copy gene. Expression levels of this gene, examined by Q-PCR, revealed higher levels in developing seeds storing oil than in leaves, stems, roots or seedling cotyledons...

  8. Preconcentration and determination of trace metal ions from aqueous samples by newly developed gallic acid modified Amberlite XAD-16 chelating resin.

    Science.gov (United States)

    Sharma, R K; Pant, Parul

    2009-04-15

    Gallic acid was immobilized on Amberlite XAD-16 by coupling it through -N=N group. The resulting chelating resin Amberlite XAD-16 gallic acid, characterized by thermogravimetric analysis (TGA), infrared (IR) spectra and BET analysis, was used to preconcentrate Cr(III), Mn(II),Fe(III),Co(II), Ni(II) and Cu(II)ions. The resin was employed for the preconcentration of the metal ions present in river water and industrial area aqueous samples. Several parameters like effect of pH, effect of time, effect of sample volume and flow rate of sample were investigated. The sorption capacities for the resin were 216 micromol g(-1), 180 micromol g(-1), 403 micromol g(-1), 281 micromol g(-1), 250 micromol g(-1) and 344 micromol g(-1) for Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) respectively. The preconcentration factors for Cr(III), Mn(II), Fe(III), Ni(II), Co(II) and Cu(II) were found out to be 300, 200, 400, 285.7, 300 and 400 respectively. The effect of various interfering ions was also studied. Results were validated by using standard addition method for river water sample.

  9. Resin glycosides from Porana duclouxii.

    Science.gov (United States)

    Ding, Wen-Bing; Zhang, Dai-Gui; Liu, Chun-Jie; Li, Guan-Hua; Li, You-Zhi

    2014-01-01

    A new intact resin glycoside (3) and two glycosidic acids (1 and 2), all having a common trisaccharide moiety and (11S)-hydroxytetradecanoic acid or (3S,11S)-dihydroxytetradecanoic acid as the aglycone, were obtained from the roots of Porana duclouxii. Their structures were elucidated by spectroscopic analyses and chemical correlations. These compounds represent the first examples of resin glycosides from the genus Porana.

  10. Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish

    Directory of Open Access Journals (Sweden)

    Enyu Yee-Ling

    2008-11-01

    Full Text Available Abstract Background Although unsaturated fatty acids such as eicosapentaenoic acid (EPA, C20:5n-3, docosahexaenoic acid (DHA, C22:6n-3 and arachidonic acid (ARA, C20:4n-6, collectively known as the highly unsaturated fatty acids (HUFA, play pivotal roles in vertebrate reproduction, very little is known about their synthesis in the ovary. The zebrafish (Danio rerio display capability to synthesize all three HUFA via pathways involving desaturation and elongation of two precursors, the linoleic acid (LA, C18:2n-6 and linolenic acid (LNA, C18:3n-3. As a prerequisite to gain full understanding on the importance and regulation of ovarian HUFA synthesis, we described here the mRNA expression pattern of two enzymes; desaturase (fadsd6 and elongase (elovl5, involved in HUFA biosynthesis pathway, in different zebrafish ovarian follicle stages. Concurrently, the fatty acid profile of each follicle stage was also analyzed. Methods mRNA levels of fadsd6 and elovl5 in different ovarian follicle stages were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR assays. For analysis of the ovarian follicular fatty acid composition, gas chromatography was used. Results Our results have shown that desaturase displayed significant upregulation in expression during the oocyte maturation stage. Expression of elongase was significantly highest in pre-vitellogenic follicles, followed by maturation stage. Fatty acid composition analysis of different ovarian follicle stages also showed that ARA level was significantly highest in pre-vitellogenic and matured follicles. DHA level was highest in both late vitellogenic and maturation stage. Conclusion Collectively, our findings seem to suggest the existence of a HUFA synthesis system, which could be responsible for the synthesis of HUFA to promote oocyte maturation and possibly ovulation processes. The many advantages of zebrafish as model system to understand folliculogenesis will be

  11. Effect of the Acidic Dental Resin Monomer 10-methacryloyloxydecyl Dihydrogen Phosphate on Odontoblastic Differentiation of Human Dental Pulp Cells.

    Science.gov (United States)

    Kim, Eun-Cheol; Park, Haejin; Lee, Sang-Im; Kim, Sun-Young

    2015-11-01

    Although 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) is frequently used as an acidic resin monomer in dental adhesives, its effect on dental pulp cells (DPCs) has been rarely reported. The purpose of this study was to examine the effects of 10-MDP on the inflammatory response and odontoblastic differentiation of DPCs at minimally toxic concentrations. We found that 10-MDP caused the release of inflammatory cytokines including NO, PGE2, iNOS, COX-2, TNF-α, IL-1β, IL-6 and IL-8 in a concentration-dependent manner. In addition, 10-MDP reduced alkaline phosphatase activity, mineralization nodule formation and mRNA expression of odontoblastic differentiation markers such as dentin sialophosphoprotein, dentin matrix protein-1, osterix and Runx2 in a concentration-dependent manner with low toxicity. In addition, 10-MDP induced activation of nuclear factor-E2-related factor 2 (Nrf2) and its target gene, haeme oxygenase-1 (HO-1). We evaluated whether the effect of 10-MDP was related to the induction of HO-1 and found that treatment with a selective inhibitor of HO-1 reversed the production of 10-MDP-mediated pro-inflammatory cytokines and the inhibition of differentiation markers. Pre-treatment with either a GSH synthesis inhibitor or antioxidants blocked 10-MDP-induced mitogen-activated protein kinases (MAPKs), Nrf2 and NF-κB pathways. Taken together, the results of this study showed that minimally toxic concentrations of 10-MDP promoted an inflammatory response and suppressed odontoblastic differentiation of DPCs by activating Nrf2-mediated HO-1 induction through MAPK and NF-κB signalling. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  12. Use of a phenolic-carboxylic acid cation resin in the treatment of low-level liquid waste at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Chilton, J.M.

    1981-09-01

    The loading capacity of CS-100 resin, using plant waste as feed, was found to be significantly reduced after 20 loading-elution cycles; one-fourth or less of the original capacity was retained after 30 cycles. No important differences were noted between an untreated column and a column that had been reconverted to the sodium form in the regeneration step. Omission of the sodium regeneration could not be adopted as a routine procedure because it produced a packing effect in the plant beds; however, reconversion to the sodium form is now achieved by using a stoichiometric amount of caustic rather than a 100% excess, as was previous practice. Since the distribution coefficients for calcium and strontium are about six times greater than that for cesium, no loss of 90 Sr would be expected while 137 Cs is loading. Laboratory results obtained by using plant conditions and feed indicate that a typical bed would remove 96% of 90 Sr in the feed. Cobalt-60 is generally the greatest contributor to the radioactivity of the plant effluent. Laboratory tests indicate that this 60 Co is present as a mixture of a soluble anionic complex and insoluble colloids. The anionic complex could be removed by placing an anion exchange column in the effluent from the CS-100 resin bed. In studies of the dynamics of loading on CS-100 resin, the contact time in plant operation (3 to 4 min per column volume) was found to be more than adequate to obtain the desired results. Effects of flow velocity were not investigated. Data from a series of laboratory experiments show that CS-100 resin can be eluted satisfactorily with 0.5 to 1.0 M formic or acetic acid, although a larger volume is required than for elution with 0.5 M nitric acid

  13. Effect of acid etching duration on tensile bond strength of composite resin bonded to erbium:yttrium-aluminium-garnet laser-prepared dentine. Preliminary study.

    Science.gov (United States)

    Chousterman, M; Heysselaer, D; Dridi, S M; Bayet, F; Misset, B; Lamard, L; Peremans, A; Nyssen-Behets, C; Nammour, S

    2010-11-01

    The purpose of this study was to compare the tensile bond strength of composite resin bonded to erbium:yttrium-aluminium-garnet (Er:YAG) laser-prepared dentine after different durations of acid etching. The occlusal third of 68 human third molars was removed in order to expose the dentine surface. The teeth were randomly divided into five groups: group B (control group), prepared with bur and total etch system with 15 s acid etching [37% orthophosphoric acid (H(3)PO(4))]; group L15, laser photo-ablated dentine (200 mJ) (laser irradiation conditions: pulse duration 100 micros, air-water spray, fluence 31.45 J/ cm(2), 10 Hz, non-contact hand pieces, beam spot size 0.9 mm, irradiation speed 3 mm/s, and total irradiation time 2 x 40 s); group L30, laser prepared, laser conditioned and 30 s acid etching; group L60, laser prepared, laser conditioned and 60 s acid etching; group L90, laser prepared, laser conditioned and 90 s acid etching. A plot of composite resin was bonded onto each exposed dentine and then tested for tensile bond strength. The values obtained were statistically analysed by analysis of variance (ANOVA) coupled with the Tukey-Kramer test at the 95% level. A 90 s acid etching before bonding showed the best bonding value (P < 0.05) when compared with all the other groups including the control group. There is no significance difference between other groups, nor within each group and the control group. There was a significant increase in tensile bond strength of the samples acid etched for 90 s.

  14. Perturbed porphyrin biosynthesis contributes to differential herbicidal symptoms in photodynamically stressed rice (Oryza sativa) treated with 5-aminolevulinic acid and oxyfluorfen.

    Science.gov (United States)

    Phung, Thu-Ha; Jung, Sunyo

    2014-11-01

    This paper focuses on the molecular mechanism of deregulated porphyrin biosynthesis in rice plants under photodynamic stress imposed by an exogenous supply of 5-aminolevulinic acid (ALA) and oxyfluorfen (OF). Plants treated with 5 mM ALA or 50 µM OF exhibited differential herbicidal symptoms as characterized by white and brown necrosis, respectively, with substantial increases in cellular leakage and malondialdehyde production. Protoporphyrin IX accumulated to higher levels after 1 day of ALA and OF treatment, whereas it decreased to the control level after 2 days of ALA treatment. Plants responded to OF by greatly decreasing the levels of Mg-protoporphyrin IX (MgProto IX), MgProto IX methyl ester, and protochlorophyllide to levels lower than control, whereas their levels drastically increased 1 day after ALA treatment and then disappeared 2 days after the treatment. Enzyme activity and transcript levels of HEMA1, GSA and ALAD for ALA synthesis greatly decreased in ALA- and OF-treated plants. Transcript levels of PPO1, CHLH, CHLI, and PORB genes involving Mg-porphyrin synthesis continuously decreased in ALA- and OF-treated plants, with greater decreases in ALA-treated plants. By contrast, up-regulation of FC2 and HO2 genes in Fe-porphyrin branch was noticeable in ALA and OF-treated plants 1 day and 2 days after the treatments, respectively. Decreased transcript levels of nuclear-encoded genes Lhcb1, Lhcb6, and RbcS were accompanied by disappearance of MgProto IX in ALA- and OF-treated plants after 2 days of the treatments. Under photodynamic stress imposed by ALA and OF, tight control of porphyrin biosynthesis prevents accumulation of toxic metabolic intermediates not only by down-regulation of their biosynthesis but also by photodynamic degradation. The up-regulation of FC2 and HO2 also appears to compensate for the photodynamic stress-induced damage. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Assessment of a land-locked Atlantic salmon (Salmo salar L.) population as a potential genetic resource with a focus on long-chain polyunsaturated fatty acid biosynthesis.

    Science.gov (United States)

    Betancor, M B; Olsen, R E; Solstorm, D; Skulstad, O F; Tocher, D R

    2016-03-01

    The natural food for Atlantic salmon (Salmo salar) in freshwater has relatively lower levels of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) than found in prey for post-smolt salmon in seawater. Land-locked salmon such as the Gullspång population feed exclusively on freshwater type lipids during its entire life cycle, a successful adaptation derived from divergent evolution. Studying land-locked populations may provide insights into the molecular and genetic control mechanisms that determine and regulate n-3 LC-PUFA biosynthesis and retention in Atlantic salmon. A two factorial study was performed comparing land-locked and farmed salmon parr fed diets formulated with fish or rapeseed oil for 8 weeks. The land-locked parr had higher capacity to synthesise n-3 LC-PUFA as indicated by higher expression and activity of desaturase and elongase enzymes. The data suggested that the land-locked salmon had reduced sensitivity to dietary fatty acid composition and that dietary docosahexaenoic acid (DHA) did not appear to suppress expression of LC-PUFA biosynthetic genes or activity of the biosynthesis pathway, probably an evolutionary adaptation to a natural diet lower in DHA. Increased biosynthetic activity did not translate to enhanced n-3 LC-PUFA contents in the flesh and diet was the only factor affecting this parameter. Additionally, high lipogenic and glycolytic potentials were found in land-locked salmon, together with decreased lipolysis which in turn could indicate increased use of carbohydrates as an energy source and a sparing of lipid. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Supplementation with linoleic acid-rich soybean oil stimulates macrophage foam cell formation via increased oxidative stress and diacylglycerol acyltransferase1-mediated triglyceride biosynthesis.

    Science.gov (United States)

    Rom, Oren; Jeries, Helana; Hayek, Tony; Aviram, Michael

    2017-01-02

    During the last decades there has been a staggering rise in human consumption of soybean oil (SO) and its major polyunsaturated fatty acid linoleic acid (LA). The role of SO or LA in cardiovascular diseases is highly controversial, and their impact on macrophage foam cell formation, the hallmark of early atherogenesis, is unclear. To investigate the effects of high SO or LA intake on macrophage lipid metabolism and the related mechanisms of action, C57BL/6 mice were orally supplemented with increasing levels of SO-based emulsion or equivalent levels of purified LA for 1 month, followed by analyses of lipid accumulation and peroxidation in aortas, serum and in peritoneal macrophages (MPM) of the mice. Lipid peroxidation and triglyceride mass in aortas from SO or LA supplemented mice were dose-dependently and significantly increased. In MPM from SO or LA supplemented mice, lipid peroxides were significantly increased and a marked accumulation of cellular triglycerides was found in accordance with enhanced triglyceride biosynthesis rate and overexpression of diacylglycerol acyltransferase1 (DGAT1), the key enzyme in triglyceride biosynthesis. In cultured J774A.1 macrophages treated with SO or LA, triglyceride accumulated via increased oxidative stress and a p38 mitogen-activated protein kinase (MAPK)-mediated overexpression of DGAT1. Accordingly, anti-oxidants (pomegranate polyphenols), inhibition of p38 MAPK (by SB202190) or DGAT1 (by oleanolic acid), all significantly attenuated SO or LA-induced macrophage triglyceride accumulation. These findings reveal novel mechanisms by which supplementation with SO or LA stimulate macrophage foam cell formation, suggesting a pro-atherogenic role for overconsumption of SO or LA. © 2016 BioFactors, 43(1):100-116, 2017. © 2016 International Union of Biochemistry and Molecular Biology.

  17. Arabidopsis and Maize RidA Proteins Preempt Reactive Enamine/Imine Damage to Branched-Chain Amino Acid Biosynthesis in Plastids[C][W][OPEN

    Science.gov (United States)

    Niehaus, Thomas D.; Nguyen, Thuy N.D.; Gidda, Satinder K.; ElBadawi-Sidhu, Mona; Lambrecht, Jennifer A.; McCarty, Donald R.; Downs, Diana M.; Cooper, Arthur J.L.; Fiehn, Oliver; Mullen, Robert T.; Hanson, Andrew D.

    2014-01-01

    RidA (for Reactive Intermediate Deaminase A) proteins are ubiquitous, yet their function in eukaryotes is unclear. It is known that deleting Salmonella enterica ridA causes Ser sensitivity and that S. enterica RidA and its homologs from other organisms hydrolyze the enamine/imine intermediates that Thr dehydratase forms from Ser or Thr. In S. enterica, the Ser-derived enamine/imine inactivates a branched-chain aminotransferase; RidA prevents this damage. Arabidopsis thaliana and maize (Zea mays) have a RidA homolog that is predicted to be plastidial. Expression of either homolog complemented the Ser sensitivity of the S. enterica ridA mutant. The purified proteins hydrolyzed the enamines/imines formed by Thr dehydratase from Ser or Thr and protected the Arabidopsis plastidial branched-chain aminotransferase BCAT3 from inactivation by the Ser-derived enamine/imine. In vitro chloroplast import assays and in vivo localization of green fluorescent protein fusions showed that Arabidopsis RidA and Thr dehydratase are chloroplast targeted. Disrupting Arabidopsis RidA reduced root growth and raised the root and shoot levels of the branched-chain amino acid biosynthesis intermediate 2-oxobutanoate; Ser treatment exacerbated these effects in roots. Supplying Ile reversed the root growth defect. These results indicate that plastidial RidA proteins can preempt damage to BCAT3 and Ile biosynthesis by hydrolyzing the Ser-derived enamine/imine product of Thr dehydratase. PMID:25070638

  18. Characterisation of the l-Cystine β-Lyase PatB from Phaeobacter inhibens: An Enzyme Involved in the Biosynthesis of the Marine Antibiotic Tropodithietic Acid.

    Science.gov (United States)

    Dickschat, Jeroen S; Rinkel, Jan; Klapschinski, Tim; Petersen, Jörn

    2017-11-16

    The l-cystine β-lyase from Phaeobacter inhibens is involved in the biosynthesis of the sulfur-containing antibiotic tropodithietic acid. The recombinant enzyme was obtained by heterologous expression in Escherichia coli and biochemically characterised by unambiguous chemical identification of the products formed from the substrate l-cystine, investigation of the substrate spectrum, determination of the enzyme kinetics, sequence alignment with closely related homologues and site-directed mutagenesis to identify a highly conserved lysine residue that is critical for functionality. PatB from P. inhibens is a new member of the small group of characterised l-cystine β-lyases and the first example of an enzyme with such an activity that is required for the biosynthesis of an antibiotic. A comparison of PatB to previously reported enzymes with l-cystine β-lyase activity from bacteria and plants is given. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Saponin Biosynthesis in Saponaria vaccaria. cDNAs Encoding β-Amyrin Synthase and a Triterpene Carboxylic Acid Glucosyltransferase1[OA

    Science.gov (United States)

    Meesapyodsuk, Dauenpen; Balsevich, John; Reed, Darwin W.; Covello, Patrick S.

    2007-01-01

    Saponaria vaccaria (Caryophyllaceae), a soapwort, known in western Canada as cowcockle, contains bioactive oleanane-type saponins similar to those found in soapbark tree (Quillaja saponaria; Rosaceae). To improve our understanding of the biosynthesis of these saponins, a combined polymerase chain reaction and expressed sequence tag approach was taken to identify the genes involved. A cDNA encoding a β-amyrin synthase (SvBS) was isolated by reverse transcription-polymerase chain reaction and characterized by expression in yeast (Saccharomyces cerevisiae). The SvBS gene is predominantly expressed in leaves. A S. vaccaria developing seed expressed sequence tag collection was developed and used for the isolation of a full-length cDNA bearing sequence similarity to ester-forming glycosyltransferases. The gene product of the cDNA, classified as UGT74M1, was expressed in Escherichia coli, purified, and identified as a triterpene carboxylic acid glucosyltransferase. UGT74M1 is expressed in roots and leaves and appears to be involved in monodesmoside biosynthesis in S. vaccaria. PMID:17172290

  20. Adsorption kinetics, isotherm, and thermodynamics studies of acetyl-11-keto-β-boswellic acids (AKBA) from Boswellia serrata extract using macroporous resin.

    Science.gov (United States)

    Niphadkar, Sonali S; Rathod, Virendra K

    2017-09-14

    An acetyl-11-keto-β-boswellic acid (AKBA) is potent anti-inflammatory agent found in Boswellia serrata oleogum resin. Adsorption characteristics of AKBA from B. serrata were studied using macroporous adsorbent resin to understand separation and adsorption mechanism of targeted molecules. Different macroporous resins were screened for adsorption and desorption of AKBA and Indion 830 was screened as it showed higher adsorption capacity. The kinetic equations were studied and results showed that the adsorption of AKBA on Indion 830 was well fitted to the pseudo first-order kinetic model. The influence of two parameters such as temperature (298, 303, and 308 K) and pH (5-8) on the adsorption process was also studied. The experimental data was further investigated using Langmuir, Freundlich, and Temkin isotherm models. It was observed that Langmuir isotherm model was found to be the best fit for AKBA adsorption by Indion 830 and highest adsorption capacity (50.34 mg/g) was obtained at temperature of 303 K. The values of thermodynamic parameters such as the change of Gibbs free energy (ΔG*), entropy (ΔS*), and enthalpy (ΔH*), indicated that the process of adsorption was spontaneous, favourable, and exothermic.

  1. Ion exchange removal of chromium (iii) from tannery wastes by using a strong acid cation exchange resin amberlite ir-120 h+ and its hybrids

    International Nuclear Information System (INIS)

    Ahmad, T.

    2014-01-01

    A strong acid cation exchange resin Amberlite IR-120 H+ and its hybrids with Mn(OH)/sub 2/, Cu(OH)/sub 2/ and Fe(OH)/sub 3/ are used for the removal of chromium (III) from spent tannery bath. The experimental data give good fits with the Langmuir sorption model. The thermodynamic parameters entropy (delta S), enthalpy (delta H) and free energy (delta G) changes are computed, which reveal that the chromium removal from tannery wastes by ion exchangers is an endothermic, physical sorption and entropically driven process. The rate of sorption is found to increase with the increase of resin dosage, stirring speed and temperature. Different kinetic models such as film diffusion, particle diffusion and Lagergren pseudo first order are used to evaluate the mechanism of the process. It is found that the hybrid ion exchange resins have better removal capacity as compared to the parent ion exchanger. The increase in the removal capacity is found to be in the order of the corresponding PZC values of the hybrid ion exchangers. Further, it is suggested that the higher exchange capacity is the result of Donnan effect and specific adsorption of chromium by the oxides / hydroxides present inside the matrix of the organic cation exchanger. (author)

  2. Transcriptome Analysis of Salicylic Acid Treatment in Rehmannia glutinosa Hairy Roots Using RNA-seq Technique for Identification of Genes Involved in Acteoside Biosynthesis

    Directory of Open Access Journals (Sweden)

    Fengqing Wang

    2017-05-01

    Full Text Available Rehmannia glutinosa is a common bulk medicinal material that has been widely used in China due to its active ingredients. Acteoside, one of the ingredients, has antioxidant, antinephritic, anti-inflammatory, hepatoprotective, immunomodulatory, and neuroprotective effects, is usually selected as a quality-control component for R. glutinosa herb in the Chinese Pharmacopeia. The acteoside biosynthesis pathway in R. glutinosa has not yet been clearly established. Herein, we describe the establishment of a genetic transformation system for R. glutinosa mediated by Agrobacterium rhizogenes. We screened the optimal elicitors that markedly increased acteoside accumulation in R. glutinosa hairy roots. We found that acteoside accumulation dramatically increased with the addition of salicylic acid (SA; the optimal SA dose was 25 μmol/L for hairy roots. RNA-seq was applied to analyze the transcriptomic changes in hairy roots treated with SA for 24 h in comparison with an untreated control. A total of 3,716, 4,018, and 2,715 differentially expressed transcripts (DETs were identified in 0 h-vs.-12 h, 0 h-vs.-24 h, and 12 h-vs.-24 h libraries, respectively. KEGG pathway-based analysis revealed that 127 DETs were enriched in “phenylpropanoid biosynthesis.” Of 219 putative unigenes involved in acteoside biosynthesis, 54 were found to be up-regulated at at least one of the time points after SA treatment. Selected candidate genes were analyzed by quantitative real-time PCR (qRT-PCR in hairy roots with SA, methyl jasmonate (MeJA, AgNO3 (Ag+, and putrescine (Put treatment. All genes investigated were up-regulated by SA treatment, and most candidate genes were weakly increased by MeJA to some degree. Furthermore, transcription abundance of eight candidate genes in tuberous roots of the high-acteoside-content (HA cultivar QH were higher than those of the low-acteoside-content (LA cultivar Wen 85-5. These results will pave the way for understanding the molecular

  3. Kinetics of soybean oil epoxidation with peracetic acid formed in situ in the presence of an ion exchange resin: Pseudo-homogeneous model

    Directory of Open Access Journals (Sweden)

    Janković Milovan

    2017-01-01

    Full Text Available A kinetic model was proposed for the epoxidation of vegetable oils with peracetic acid formed in situ from acetic acid and hydrogen peroxide in the presence of an acidic ion exchange resin as a catalyst. The model is pseudo-homogeneous with respect to the catalyst. Besides the main reactions of peracetic acid and epoxy ring formation, the model takes into account the side reaction of epoxy ring opening with acetic acid. The partitioning of acetic acid and peracetic acid between the aqueous and organic phases and the change in the phases’ volumes during the process were considered. The temperature dependency of the apparent reaction rate coefficients is described by a reparameterized Arrhenius equation. The constants in the proposed model were estimated by fitting the experimental data obtained for the epoxidations of soybean oil conducted under defined reaction conditions. The highest epoxy yield of 87.73% was obtained at 338 K when the mole ratio of oil unsaturation:acetic acid:hydrogen peroxide was 1:0.5:1.35 and when the amount of the catalyst Amberlite IR-120H was 4.04 wt.% of oil. Compared to the other reported pseudo-homogeneous models, the model proposed in this study better correlates the change of double bond and epoxy group contents during the epoxidation process. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45022

  4. Uranium recovery and uranium remove from acid mine waters by ion exchange resin; Remocao e recuperacao de uranio de aguas acidas de mina com resina de troca ionica

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Marcos R.L. [Comissao Nacional de Energia Nuclear (CNEN), Pocos de Caldas, MG (Brazil). Coordenacao do Laborarorio; Fatibello Filho, Orlando [Sao Carlos Univ., SP (Brazil). Dept. de Quimica

    1999-11-01

    Ion exchange using resins is one of few processes capable of reducing contaminants in effluents to very low levels according to environmental legislation. In this study the process was used to remove and recovery uranium from acid mine waters at Pocos de Caldas-MG Uranium Mining and Milling Plant. The presence of pyrite in the waste rock piles, resulting acid drainage with several pollutants. Including uranium ranging from 6 to 14 mg/l, as sulfate complex, that can be removed by an anionic exchanger. Studies of uranium sorption without treatment, and with lime pretreatment of water to precipitate the iron and recovery uranium as commercial product, are presented. Uranium elution was done with NaCl solutions. Saline concentration and retention time were the parameters studied. the uranium decontaminations level in the effluents from acid mine water was 94%. (author) 10 refs., 6 tabs., 3 figs.

  5. Human disease isolates of serotype m4 and m22 group a streptococcus lack genes required for hyaluronic acid capsule biosynthesis.

    Science.gov (United States)

    Flores, Anthony R; Jewell, Brittany E; Fittipaldi, Nahuel; Beres, Stephen B; Musser, James M

    2012-11-06

    Group A streptococcus (GAS) causes human pharyngitis and invasive infections and frequently colonizes individuals asymptomatically. Many lines of evidence generated over decades have shown that the hyaluronic acid capsule is a major virulence factor contributing to these infections. While conducting a whole-genome analysis of the in vivo molecular genetic changes that occur in GAS during longitudinal human pharyngeal interaction, we discovered that serotypes M4 and M22 GAS strains lack the hasABC genes necessary for hyaluronic acid capsule biosynthesis. Using targeted PCR, we found that all 491 temporally and geographically diverse disease isolates of these two serotypes studied lack the hasABC genes. Consistent with the lack of capsule synthesis genes, none of the strains produced detectable hyaluronic acid. Despite the lack of a hyaluronic acid capsule, all strains tested multiplied extensively ex vivo in human blood. Thus, counter to the prevailing concept in GAS pathogenesis research, strains of these two serotypes do not require hyaluronic acid to colonize the upper respiratory tract or cause abundant mucosal or invasive human infections. We speculate that serotype M4 and M22 GAS have alternative, compensatory mechanisms that promote virulence. A century of study of the antiphagocytic hyaluronic acid capsule made by group A streptococcus has led to the concept that it is a major virulence factor contributing to human pharyngeal and invasive infections. However, the discovery that some strains that cause abundant human infections lack hyaluronic acid biosynthetic genes and fail to produce this capsule provides a new stimulus for research designed to understand the group A streptococcus factors contributing to pharyngeal infection and invasive disease episodes.

  6. Evaluation of biosynthetic pathways to delta-aminolevulinic acid in Propionibacterium shermanii based on biosynthesis of vitamin B12 from D-[1-13C]glucose.

    Science.gov (United States)

    Iida, K; Kajiwara, M

    2000-04-04

    Analysis of the (13)C nuclear magnetic resonance (NMR) spectrum of (13)C-labeled vitamin B(12) biosynthesized from D-[1-(13)C]glucose by Propionibacterium shermanii provided evidence suggesting that delta-aminolevulinic acid (ALA) incorporated in the (13)C-labeled vitamin B(12) may have been synthesized via both the Shemin pathway and the C5 pathway under anaerobic conditions in the ratio of 1 < [(ratio of ALA biosynthesis from the Shemin pathway)/(that from the C5 pathway)] < 1.8. The D-ribose moiety of vitamin B(12) was labeled with (13)C at R-1, R-3, and R-5. The aminopropanol moiety of vitamin B(12) was labeled on Pr-1 and Pr-2, but not Pr-3.

  7. Human COQ9 Rescues a coq9 Yeast Mutant by Enhancing Coenzyme Q Biosynthesis from 4-Hydroxybenzoic Acid and Stabilizing the CoQ-Synthome

    Science.gov (United States)

    He, Cuiwen H.; Black, Dylan S.; Allan, Christopher M.; Meunier, Brigitte; Rahman, Shamima; Clarke, Catherine F.

    2017-01-01

    Coq9 is required for the stability of a mitochondrial multi-subunit complex, termed the CoQ-synthome, and the deamination step of Q intermediates that derive from para-aminobenzoic acid (pABA) in yeast. In human, mutations in the COQ9 gene cause neonatal-onset primary Q10 deficiency. In this study, we determined whether expression of human COQ9 could complement yeast coq9 point or null mutants. We found that expression of human COQ9 rescues the growth of the temperature-sensitive yeast mutant, coq9-ts19, on a non-fermentable carbon source and increases the content of Q6, by enhancing Q biosynthesis from 4-hydroxybenzoic acid (4HB). To study the mechanism for the rescue by human COQ9, we determined the steady-state levels of yeast Coq polypeptides in the mitochondria of the temperature-sensitive yeast coq9 mutant expressing human COQ9. We show that the expression of human COQ9 significantly increased steady-state levels of yeast Coq4, Coq6, Coq7, and Coq9 at permissive temperature. Human COQ9 polypeptide levels persisted at non-permissive temperature. A small amount of the human COQ9 co-purified with tagged Coq6, Coq6-CNAP, indicating that human COQ9 interacts with the yeast Q-biosynthetic complex. These findings suggest that human COQ9 rescues the yeast coq9 temperature-sensitive mutant by stabilizing the CoQ-synthome and increasing Q biosynthesis from 4HB. This finding provides a powerful approach to studying the function of human COQ9 using yeast as a model. PMID:28736527

  8. Human COQ9 Rescues a coq9 Yeast Mutant by Enhancing Coenzyme Q Biosynthesis from 4-Hydroxybenzoic Acid and Stabilizing the CoQ-Synthome

    Directory of Open Access Journals (Sweden)

    Cuiwen H. He

    2017-07-01

    Full Text Available Coq9 is required for the stability of a mitochondrial multi-subunit complex, termed the CoQ-synthome, and the deamination step of Q intermediates that derive from para-aminobenzoic acid (pABA in yeast. In human, mutations in the COQ9 gene cause neonatal-onset primary Q10 deficiency. In this study, we determined whether expression of human COQ9 could complement yeast coq9 point or null mutants. We found that expression of human COQ9 rescues the growth of the temperature-sensitive yeast mutant, coq9-ts19, on a non-fermentable carbon source and increases the content of Q6, by enhancing Q biosynthesis from 4-hydroxybenzoic acid (4HB. To study the mechanism for the rescue by human COQ9, we determined the steady-state levels of yeast Coq polypeptides in the mitochondria of the temperature-sensitive yeast coq9 mutant expressing human COQ9. We show that the expression of human COQ9 significantly increased steady-state levels of yeast Coq4, Coq6, Coq7, and Coq9 at permissive temperature. Human COQ9 polypeptide levels persisted at non-permissive temperature. A small amount of the human COQ9 co-purified with tagged Coq6, Coq6-CNAP, indicating that human COQ9 interacts with the yeast Q-biosynthetic complex. These findings suggest that human COQ9 rescues the yeast coq9 temperature-sensitive mutant by stabilizing the CoQ-synthome and increasing Q biosynthesis from 4HB. This finding provides a powerful approach to studying the function of human COQ9 using yeast as a model.

  9. Reaction catalysts of urea-formaldehyde resin, as related to strength properties of southern pine particleboard

    Science.gov (United States)

    C. -Y. Hse

    1974-01-01

    Twelve resins were formulated with factorial combinations of three alkaline catalysts (i.e., somdium hydroxide, hexamethylenetetramine, and triethanolamine) and four acidic catalysts (i.e., acetic acid, hydrochloric acid, ammonium chloride, and phosphoric acid). The resins were replicated.

  10. Amino Acids in the TM4-TM5 loop of Na,K-ATPase Are Important for Biosynthesis

    DEFF Research Database (Denmark)

    Jørgensen, Jesper Roland; Houghton-Larsen, Jens; Jacobsen, Mette Dorph

    2003-01-01

    -sensitive folding mutants, as they induce the unfolded protein response at 30°C but not at 15°C. We used an algorithm to predict that residues 868ENGFLIPIHLL878 in the L78 loop exposed to the endoplasmic reticulum lumen constitute the most likely BiP binding site. Correct folding of this sequence may be important...... in the endoplasmic reticulum quality control, as the same loop is responsible for the a-ß-associations required to leave this compartment. On the basis of the Ca-ATPase crystal structure and the presented data, we propose a model to account for the role of the TM4-TM5 loop in Na,K-ATPase biosynthesis....

  11. Expression of genes controlling unsaturated fatty acids biosynthesis and oil deposition in developing seeds of Sacha inchi (Plukenetia volubilis L.).

    Science.gov (United States)

    Wang, Xiaojuan; Liu, Aizhong

    2014-10-01

    Sacha inchi (Plukenetia volubilis L., Euphorbiaceae) seed oil is rich in α-linolenic acid, a kind of n-3 fatty acids with many health benefits. To discover the mechanism underlying α-linolenic acid accumulation in sacha inchi seeds, preliminary research on sacha inchi seed development was carried out from one week after fertilization until maturity, focusing on phenology, oil content, and lipid profiles. The results suggested that the development of sacha inchi seeds from pollination to mature seed could be divided into three periods. In addition, investigations on the effect of temperature on sacha inchi seeds showed that total oil content decreased in the cool season, while unsaturated fatty acid and linolenic acid concentrations increased. In parallel, expression profiles of 17 unsaturated fatty acid related genes were characterized during seed development and the relationships between gene expression and lipid/unsaturated fatty acid accumulation were discussed.

  12. Di-D-fructose dianhydride-enriched products by acid ion-exchange resin-promoted caramelization of D-fructose: chemical analyses.

    Science.gov (United States)

    Suárez-Pereira, Elena; Rubio, Enrique M; Pilard, Serge; Ortiz Mellet, Carmen; García Fernández, José M

    2010-02-10

    Caramelization commonly occurs when sugars, or products containing a high proportion of sugars, are heated either dry or in concentrated aqueous solutions, alone or in the presence of certain additives. Upon thermal treatment of sugars, dehydration and self-condensation reactions occur, giving rise to volatiles (principally 2-hydroxymethylfurfural, HMF), pigments (melanoidines) and oligosaccharidic material, among which di-D-fructose dianhydrides (DFAs) and glycosylated DFA derivatives of different degree of polymerization (DP) have been identified. This study reports a methodology to produce caramel-like products with a high content of DFAs and oligosaccharides thereof from commercial D-fructose based on the use of acid ion-exchange resins as caramelization promotors. The rate of formation of these compounds as a function of D-fructose concentration, catalyst proportion, temperature, catalyst nature and particle size has been investigated. The use of sulfonic acid resins allows conducting caramelization at remarkable low temperatures (70-90 degrees C) to reach conversions into DFA derivatives up to 70-80% in 1-2 h, with relative proportions of HMF < 2%.The relative abundance of individual DFA structures can be modulated by acting on the catalyst nature and reaction conditions, which offers a unique opportunity for nutritional studies of DFA-enriched products with well-defined compositions.

  13. Expanding metabolic pathway for de novo biosynthesis of the chiral pharmaceutical intermediate l-pipecolic acid in Escherichia coli

    OpenAIRE

    Ying, Hanxiao; Tao, Sha; Wang, Jing; Ma, Weichao; Chen, Kequan; Wang, Xin; Ouyang, Pingkai

    2017-01-01

    Background The six-carbon circular non-proteinogenic compound l-pipecolic acid is an important chiral drug intermediate with many applications in the pharmaceutical industry. In the present study, we developed a metabolically engineered strain of Escherichia coli for the overproduction of l-pipecolic acid from glucose. Results The metabolic pathway from l-lysine to l-pipecolic acid was constructed initially by introducing lysine cyclodeaminase (LCD). Next, l-lysine metabolic flux from glucose...

  14. Direct Assay of δ-Aminolevulinic Acid Dehydratase in Heme Biosynthesis for the Detection of Porphyrias by Tandem Mass Spectrometry

    OpenAIRE

    Choiniere, John R.; Scott, C. Ronald; Gelb, Michael H.; Tureček, František

    2010-01-01

    We report a new assay of human δ-aminolevulinic acid dehydratase (ALAD), an enzyme converting δ-aminolevulinic acid (ALA) into porphobilinogen. The assay is developed for use in the clinical diagnosis of δ-aminolevulinic acid dehydratase-deficient porphyria, a rare enzymatic deficiency of the heme biosynthetic pathway. The assay involves the incubation of erythrocyte lysate with the natural substrate, ALA, followed by quantitative in situ conversion of porphobilinogen to its butyramide, and l...

  15. Characterization of a membrane-bound C-glucosyltransferase responsible for carminic acid biosynthesis in Dactylopius coccus Costa

    OpenAIRE

    Kannangara, Rubini; Siukstaite, Lina; Borch-Jensen, Jonas; Madsen, Bjørn; Kongstad, Kenneth T.; Staerk, Dan; Bennedsen, Mads; Okkels, Finn T.; Rasmussen, Silas A.; Larsen, Thomas O.; Frandsen, Rasmus J. N.; Møller, Birger Lindberg

    2017-01-01

    Carminic acid, a glucosylated anthraquinone found in scale insects like Dactylopius coccus, has since ancient times been used as a red colorant in various applications. Here we show that a membrane-bound C-glucosyltransferase, isolated from D. coccus and designated DcUGT2, catalyzes the glucosylation of flavokermesic acid and kermesic acid into their respective C-glucosides dcII and carminic acid. DcUGT2 is predicted to be a type I integral endoplasmic reticulum (ER) membrane protein, contain...

  16. Gene expression analyses in tomato near isogenic lines provide evidence for ethylene and abscisic acid biosynthesis fine-tuning during arbuscular mycorrhiza development.

    Science.gov (United States)

    Fracetto, Giselle Gomes Monteiro; Peres, Lázaro Eustáquio Pereira; Lambais, Marcio Rodrigues

    2017-07-01

    Plant responses to the environment and microorganisms, including arbuscular mycorrhizal fungi, involve complex hormonal interactions. It is known that abscisic acid (ABA) and ethylene may be involved in the regulation of arbuscular mycorrhiza (AM) and that part of the detrimental effects of ABA deficiency in plants is due to ethylene overproduction. In this study, we aimed to determine whether the low susceptibility to mycorrhizal colonization in ABA-deficient mutants is due to high levels of ethylene and whether AM development is associated with changes in the steady-state levels of transcripts of genes involved in the biosynthesis of ethylene and ABA. For that, tomato (Solanum lycopersicum) ethylene overproducer epinastic (epi) mutant and the ABA-deficient notabilis (not) and sitiens (sit) mutants, in the same Micro-Tom (MT) genetic background, were inoculated with Rhizophagus clarus, and treated with the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG). The development of AM, as well as the steady-state levels of transcripts involved in ethylene (LeACS2, LeACO1 and LeACO4) and ABA (LeNCED) biosynthesis, was determined. The intraradical colonization in epi, not and sit mutants was significantly reduced compared to MT. The epi mutant completely restored the mycorrhizal colonization to the levels of MT with the application of 10 µM of AVG, probably due to the inhibition of the ACC synthase gene expression. The steady-state levels of LeACS2 and LeACO4 transcripts were induced in mycorrhizal roots of MT, whereas the steady-state levels of LeACO1 and LeACO4 transcripts were significantly induced in sit, and the steady-state levels of LeNCED transcripts were significantly induced in all genotypes and in mycorrhizal roots of epi mutants treated with AVG. The reduced mycorrhizal colonization in sit mutants seems not to be limited by ethylene production via ACC oxidase regulation. Both ethylene overproduction and ABA deficiency impaired AM fungal

  17. Biosynthesis of a hypermodified nucleotide in Saccharomyces carlsbergensis 17S and HeLa-cell 18S ribosomal ribonucleic acid.

    Science.gov (United States)

    Brand, R C; Klootwijk, J; Planta, R J; Maden, B E

    1978-01-01

    The biosynthesis of a hypermodified nucleotide, similar to or identical with 3-(3-amino-3-carboxypropyl)-1-methylpseudouridine monophosphate, present in Saccharomyces carlsbergensis 17S and HeLa-cell 18S rRNA, was investigated with respect to the sequence of reactions required for synthesis and their timing in ribosome maturation. In both yeast and HeLa cells methylation precedes attachment of the 3-amino-3-carboxypropyl group. In yeast the methylated precursor nucleotide was tentatively characterized as 1-methylpseudouridine. This precursor nucleotide was demonstrated in both 37S and most of the cytoplasmic 18S pre-rRNA (rRNA precursor) molecules. The synthesis of the hypermodified nucleotide is completed just before the final cleavage of 18S pre-rRNA to give 17S rRNA, so that the final addition of the 3-amino-3-carboxypropyl group is a cytoplasmic event. Comparable experiments with HeLa cells indicated that formation of 1-methylpseudouridine occurs at the level of 45S RNA and addition of the 3-amino-3-carboxypropyl group occurs in the cytoplasm on newly synthesized 18S RNA.

  18. Removal of CdTe in acidic media by magnetic ion-exchange resin: A potential recycling methodology for cadmium telluride photovoltaic waste

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Teng, E-mail: zhangteng@mail.iee.ac.cn; Dong, Zebin; Qu, Fei; Ding, Fazhu; Peng, Xingyu; Wang, Hongyan; Gu, Hongwei

    2014-08-30

    Highlights: • Sulfonated magnetic microsphere was prepared as one strong acid cation-exchange resin. • Cd and Te can be removed directly from the highly acidic leaching solution of CdTe. • Good chemical stability, fast adsorbing rate and quick magnetic separation in strong acidic media. • A potential path for recycling CdTe photovoltaic waste. - Abstract: Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste.

  19. Biosynthesis of the Nylon 12 Monomer, ω-Aminododecanoic Acid with Novel CYP153A, AlkJ, and ω-TA Enzymes.

    Science.gov (United States)

    Ahsan, Md Murshidul; Jeon, Hyunwoo; P Nadarajan, Saravanan; Chung, Taeowan; Yoo, Hee-Wang; Kim, Byung-Gee; Patil, Mahesh D; Yun, Hyungdon

    2017-12-16

    Bioplastics are derived from renewable biomass sources, such as vegetable oils, cellulose, and starches. An important and high-performance member of the bioplastic family is Nylon 12. The biosynthesis of ω-amino dodecanoic acid (ω-AmDDA), the monomer of Nylon 12 from vegetable oil derivatives is considered as an alternative to petroleum-based monomer synthesis. In this study, for the production of ω-AmDDA from dodecanoic acid (DDA), the cascade of novel P450 (CYP153A), alcohol dehydrogenase (AlkJ), and ω-transaminase (ω-TA) is developed. The regioselective ω-hydroxylation of 1 mM DDA with near complete conversion (>99%) is achieved using a whole-cell biocatalyst co-expressing CYP153A, ferredoxin reductase and ferredoxin. When the consecutive biotransformation of ω-hydroxy dodecanoic acid (ω-OHDDA) is carried out using a whole-cell biocatalyst co-expressing AlkJ and ω-TA, 1.8 mM ω-OHDDA is converted into ω-AmDDA with 87% conversion in 3 h. Finally, when a one-pot reaction is carried out with 2 mM DDA using both whole-cell systems, 0.6 mM ω-AmDDA is produced after a 5 h reaction. The results demonstrated the scope of the potential cascade reaction of novel CYP153A, AlkJ, and ω-TA for the production of industrially important bioplastic monomers, amino fatty acids, from FFAs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Molecular characterization of two cloned nitrilases from Arabidopsis thaliana: key enzymes in biosynthesis of the plant hormone indole-3-acetic acid.

    Science.gov (United States)

    Bartling, D; Seedorf, M; Schmidt, R C; Weiler, E W

    1994-01-01

    As in maize [Wright, A.D., Sampson, M. B., Neuffer, M. G., Michalczuk, L., Slovin, J. P. & Cohen, J. D. (1991) Science 254, 998-1000], the major auxin of higher plants, indole-3-acetic acid, is synthesized mainly via a nontryptophan pathway in Arabidopsis thaliana [Normanly, J., Cohen, J. D. & Fink, G. R. (1993) Proc. Natl. Acad. Sci. USA 90, 10355-10359]. In the latter species, the hormone may be accessible from the glucosinolate glucobrassicin (indole-3-methyl glucosinolate) and from L-tryptophan via indoleacetaldoxime under special circumstances. In each case, indole-3-acetonitrile is the immediate precursor, which is converted into indole-3-acetic acid through the action of nitrilase (nitrile aminohydrolase, EC 3.5.5.1). The genome of A. thaliana contains two nitrilase genes. Nitrilase I had been cloned earlier in our laboratory. The cDNA for nitrilase II (PM255) was cloned and encodes an enzyme that converts indole-3-acetonitrile to indole-3-acetic acid, the plant hormone. We show that the intracellular location as well as the expression pattern of the two A. thaliana nitrilases are distinctly different. Nitrilase I is soluble and is expressed throughout development, but at a very low level during the fruiting stage, while nitrilase II is tightly associated with the plasma membrane, is barely detectable in young rosettes, but is strongly expressed during bolting, flowering, and especially fruit development. The results indicate that more than one pathway of indole-3-acetic acid biosynthesis via indole-3-acetonitrile exists in A. thaliana and that these pathways are differentially regulated throughout plant development. Images PMID:8016109

  1. Serine biosynthesis and transport defects.

    Science.gov (United States)

    El-Hattab, Ayman W

    2016-07-01

    l-serine is a non-essential amino acid that is biosynthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, l-serine is a potent neurotrophic factor and a precursor of a number of essential compounds including phosphatidylserine, sphingomyelin, glycine, and d-serine. Serine biosynthesis defects result from impairments of PGDH, PSAT, or PSP leading to systemic serine deficiency. Serine biosynthesis defects present in a broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, a lethal multiple congenital anomaly disease, intermediately, infantile serine biosynthesis defects with severe neurological manifestations and growth deficiency, and at the mild end, the childhood disease with intellectual disability. A serine transport defect resulting from deficiency of the ASCT1, the main transporter for serine in the central nervous system, has been recently described in children with neurological manifestations that overlap with those observed in serine biosynthesis defects. l-serine therapy may be beneficial in preventing or ameliorating symptoms in serine biosynthesis and transport defects, if started before neurological damage occurs. Herein, we review serine metabolism and transport, the clinical, biochemical, and molecular aspects of serine biosynthesis and transport defects, the mechanisms of these diseases, and the potential role of serine therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Dairy Streptococcus thermophilus improves cell viability of Lactobacillus brevis NPS-QW-145 and its γ-aminobutyric acid biosynthesis ability in milk

    Science.gov (United States)

    Wu, Qinglong; Law, Yee-Song; Shah, Nagendra P.

    2015-01-01

    Most high γ-aminobutyric acid (GABA) producers are Lactobacillus brevis of plant origin, which may be not able to ferment milk well due to its poor proteolytic nature as evidenced by the absence of genes encoding extracellular proteinases in its genome. In the present study, two glutamic acid decarboxylase (GAD) genes, gadA and gadB, were found in high GABA-producing L. brevis NPS-QW-145. Co-culturing of this organism with conventional dairy starters was carried out to manufacture GABA-rich fermented milk. It was observed that all the selected strains of Streptococcus thermophilus, but not Lactobacillus delbrueckii subsp. bulgaricus, improved the viability of L. brevis NPS-QW-145 in milk. Only certain strains of S. thermophilus improved the gadA mRNA level in L. brevis NPS-QW-145, thus enhanced GABA biosynthesis by the latter. These results suggest that certain S. thermophilus strains are highly recommended to co-culture with high GABA producer for manufacturing GABA-rich fermented milk. PMID:26245488

  3. Dairy Streptococcus thermophilus improves cell viability of Lactobacillus brevis NPS-QW-145 and its γ-aminobutyric acid biosynthesis ability in milk.

    Science.gov (United States)

    Wu, Qinglong; Law, Yee-Song; Shah, Nagendra P

    2015-08-06

    Most high γ-aminobutyric acid (GABA) producers are Lactobacillus brevis of plant origin, which may be not able to ferment milk well due to its poor proteolytic nature as evidenced by the absence of genes encoding extracellular proteinases in its genome. In the present study, two glutamic acid decarboxylase (GAD) genes, gadA and gadB, were found in high GABA-producing L. brevis NPS-QW-145. Co-culturing of this organism with conventional dairy starters was carried out to manufacture GABA-rich fermented milk. It was observed that all the selected strains of Streptococcus thermophilus, but not Lactobacillus delbrueckii subsp. bulgaricus, improved the viability of L. brevis NPS-QW-145 in milk. Only certain strains of S. thermophilus improved the gadA mRNA level in L. brevis NPS-QW-145, thus enhanced GABA biosynthesis by the latter. These results suggest that certain S. thermophilus strains are highly recommended to co-culture with high GABA producer for manufacturing GABA-rich fermented milk.

  4. Effect of sodium hypochlorite and peracetic acid on the surface roughness of acrylic resin polymerized by heated water for short and long cycles.

    Science.gov (United States)

    Sczepanski, Felipe; Sczepanski, Claudia Roberta Brunnquell; Berger, Sandrine Bittencourt; Consani, Rafael Leonardo Xediek; Gonini-Júnior, Alcides; Guiraldo, Ricardo Danil

    2014-10-01

    To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test. There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances. It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness.

  5. Biosynthesis of Citric Acid from Glycerol by Acetate Mutants of Yarrowia lipolytica in Fed-Batch Fermentation

    Directory of Open Access Journals (Sweden)

    Anita Rywińska

    2009-01-01

    Full Text Available Pure and crude glycerol from biodiesel production have been used as substrates for citric acid production by acetate-negative mutants of Yarrowia lipolytica in fed-batch fermentation. Both the final concentration and the yield of the product were the highest when Y. lipolytica Wratislavia AWG7 strain was used in the culture with pure or crude glycerol. With a medium containing 200 g/L of glycerol, production reached a maximum of citric acid of 139 g/L after 120 h. This high yield of the product (up to 0.69 g of citric acid per gram of glycerol consumed was achieved with both pure and crude glycerol. Lower yield of citric acid in the culture with Y. lipolytica Wratislavia K1 strain (about 0.45 g/g resulted from increased erythritol concentrations (up to 40 g/L, accumulated simultaneously with the citric acid. The concentration of isocitric acid, a by-product in this fermentation, was very low, in the range from 2.6 to 4.6 g/L.

  6. Exposure of Atlantic salmon parr (Salmo salar) to a combination of resin acids and a water soluble fraction of diesel fuel oil: A model to investigate the chemical causes of pigmented salmon syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Croce, B. [Scottish Office Agriculture, Environment, and Fisheries Dept., Aberdeen (United Kingdom). Marine Lab.]|[Scottish Environmental Protection Agency, Aberdeen (United Kingdom). North East River Purification Board; Stagg, R.M. [Scottish Office Agriculture, Environment, and Fisheries Dept., Aberdeen (United Kingdom). Marine Lab.

    1997-09-01

    Pigmented salmon syndrome is a pollutant-induced hemolytic anemia and hyperbilirubinemia. As part of an investigation of this condition, S2 Atlantic salmon parr (Salmo salar) were exposed to a diesel fuel oil, water soluble fraction (WSF) in combination with a mixture of three resin acids (isopimaric, dehydroabietic, and abietic acids) in a continuous-flow freshwater system. The total nominal concentrations of resin acids in the exposure tanks were 10, 50, and 100 {micro}g/L; the diesel WSF was generated in situ and provided a mean hydrocarbon concentration of 2.0 {+-} 0.1 mg/L (n = 12) during the 9-d exposure period. Exposure to the diesel WSF alone depressed liver bilirubin UDP-glucuronosyl transferase (UDPGT) activity and induced phenol UDPGT activity. Exposure to the diesel WSF in the absence or presence of resin acids induced liver cytochrome P4501A and increased the concentrations in the plasma of the enzymes lactate dehydrogenase, alkaline phosphatase, and glutamic oxaloacetic transaminase. The combined exposure to diesel WSF with either 50 or 100 {micro}g/L total resin acid caused significant elevations in the concentrations of bilirubin in the plasma and many of these fish had yellow pigmentation on the ventral surface and around the gill arches. The results demonstrate that exposure to combinations of two groups of contaminants can result in the manifestation of toxic effects not apparent from exposure to either of these chemicals in isolation.

  7. Plastic casting resin poisoning

    Science.gov (United States)

    Epoxy poisoning; Resin poisoning ... Epoxy and resin can be poisonous if they are swallowed or their fumes are breathed in. ... Plastic casting resins are found in various plastic casting resin products.

  8. Resistance to fracture of endodontically treated premolars restored with glass ionomer cement or acid etch composite resin: An in vitro study

    Directory of Open Access Journals (Sweden)

    B Ranga

    2010-01-01

    Full Text Available Aim: Due to the weakness of endodontically treated posterior teeth requires more strengthened restoration to withstand occlusal forces. The purpose of the present study was to determine and compare the resistance to fracture of endodontically treated maxillary 1 st premolars restored with different materials in mesio-occluso-distal (MOD cavity preparations. Materials and Methods: MOD cavity preparations in 80 endodontically treated maxillary 1 st premolars were restored using four different methods. Fiber rings were filled with stone plaster and the teeth were placed into the plaster up to the level of cemento-enamel junction. The teeth were grouped according to restorative method, mounted in an Instrom T.T. machine, and the buccal walls subjected to a slowly increasing compressive force until fracture occurred. Result: The force of fracture of the walls of each tooth was recorded and the results in the various groups compared. All teeth fractured in a similar manner irrespective of the restorative method used. Conclusion: The resistance to the fracture of the teeth was the same when they were stored with glass ionomer cement as a base over which composite resin was placed. When the entire cavities were filled with glass ionomer cement, the resistance to fracture of the teeth decreased significantly compared with the acid etch resin technique.

  9. Effect of a self-etching primer and phosphoric acid etching on the bond strength of 4-META/MMA-TBB resin to human enamel.

    Science.gov (United States)

    Nogawa, Hiroshi; Koizumi, Hiroyasu; Saiki, Osamu; Hiraba, Haruto; Nakamura, Mitsuo; Matsumura, Hideo

    2015-01-01

    The purpose of this study was to evaluate the shear bond strength and durability of 4-META/MMA-TBB resin to human enamel. A self-etching primer that contained 4-META (Teeth Primer, TP) and 35-45% or 60-65% concentrations of phosphoric acid (K-Etchant Gel, KE, and Super Bond C&B Red Activator, RA) were used as the surface treatment agents. A methyl methacrylate (MMA)-based self-polymerizing resin (Super-Bond C&B) was used as a luting agent. The shear bond strength was determined both pre and post thermocycling. The results were statistically analyzed with a non-parametric procedure. The post-thermocycling shear bond strength of the TP group was significantly higher than that of other groups, and that of the KE group was significantly higher compared with the RA group. These results demonstrated that 4-META was effective. Furthermore, when the degree of tooth demineralization was compared, surface treatment with less demineralization using TP was the most effective treatment.

  10. Leaf oil and resin acid components of lacebark pine, pinus bungeana zucc. Shiromatsu no ha no seiyu oyobi jushi san seibun

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Nasuo; Dewa, Naoyuki; Tsuneya, Tomoyuki (Tottori Univ., Tottori (Japan). Faculty of General Education); Kageyama, Mikiko; Nakajima, Akira; Yamamoto, Jiro; Nakajima, Ruka (Shiono Koryo Co. Ltd., Osaka (Japan))

    1989-11-30

    This study had the objective to search for the leafoil component of lacebark pine (Pinus bungeana Zucc), compare it with those of several other pines and Sciadopitys verillata Sieb, et Zucc whose fragrance comparatively resembles that of lacebark pine, and clarify the difference of fragrance. In addition, with regard to the resin acid component of resin, its comparison with those of red pine and black pine was made, and furthermore, in order to clarify the feature of the fragrance of lacebark pine, comparison by the enfleurage method was made with red pine, black pine and the above Sciadopitys. The leaf oils were extracted by steam distillation on the basis of making the extraction conditions such as the amount of samples, distillation time, and the amount of distillate, etc. as same as possible. As a result, with regard to the yield of the oil obtained by steam distillation, lacebark pine {prime} s was extremely big and almost twice more than those of black pine and red pine. Concerning the oil component, lacebark pine showed especially high contents of {alpha} -thujene, {alpha} -pinene and camphene and high contents of {beta} -caryophyllene and germacrene-D. Black pine had much of pinene and red pine had much of myrcene, etc. 21 refs., 2 figs., 4 tabs.

  11. Arabinogalactan biosynthesis

    DEFF Research Database (Denmark)

    Poulsen, Christian Peter; Dilokpimol, Adiphol; Geshi, Naomi

    2015-01-01

    Arabinogalactan proteins are abundant cell surface proteoglycans in plants and are implicated to act as developmental markers during plant growth. We previously reported that AtGALT31A, AtGALT29A, and AtGLCAT14A-C, which are involved in the biosynthesis of arabinogalactan proteins, localize......GALT29A. Therefore, the electrostatic status of Y144, which is regulated by an unknown kinase/phosphatase system, may regulate AtGALT29A enzyme activity. Moreover, we have identified additional proteins, apyrase 3 (APY3; At1g14240) and UDPglucuronate epimerases 1 and 6 (GAE1, At4g30440; GAE6, At3g23820...

  12. Involvement of a Natural Fusion of a Cytochrome P450 and a Hydrolase in Mycophenolic Acid Biosynthesis

    DEFF Research Database (Denmark)

    Hansen, Bjarne Gram; Mnich, Ewelina; Nielsen, Kristian Fog

    2012-01-01

    C, a polyketide synthase producing 5-methylorsellinic acid (5-MOA). However, the biochemical role of the enzymes encoded by the remaining genes in the MPA gene cluster is still unknown. Based on bioinformatic analysis of the MPA gene cluster, we hypothesized that the step following 5-MOA production in the pathway...... that the P450 catalyzes hydroxylation of 5-MOA to 4,6-dihydroxy-2-(hydroxymethyl)-3-methylbenzoic acid (DHMB). DHMB is then converted to DHMP, and our results suggest that the hydrolase domain aids this second step by acting as a lactone synthase that catalyzes the ring closure. Overall, the chimeric enzyme...

  13. Characterization of a membrane-bound C-glucosyltransferase responsible for carminic acid biosynthesis in Dactylopius coccus Costa

    DEFF Research Database (Denmark)

    Kannangara, Rubini; Siukstaite, Lina; Borch-Jensen, Jonas

    2017-01-01

    Carminic acid, a glucosylated anthraquinone found in scale insects like Dactylopius coccus, has since ancient times been used as a red colorant in various applications. Here we show that a membrane-bound C-glucosyltransferase, isolated from D. coccus and designated DcUGT2, catalyzes the glucosyla......Carminic acid, a glucosylated anthraquinone found in scale insects like Dactylopius coccus, has since ancient times been used as a red colorant in various applications. Here we show that a membrane-bound C-glucosyltransferase, isolated from D. coccus and designated DcUGT2, catalyzes...

  14. Study on the Effect of Levulinic Acid on Whey-Based Biosynthesis of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate by Hydrogenophaga pseudoflava

    Directory of Open Access Journals (Sweden)

    Martin Koller

    2017-04-01

    Full Text Available Background and Objective: Production of polyhydroxyalkanoate copolyesters consisting of 3-hydroxybutyrate and 3-hydroxyvalerate units was for the first time studied using the production strain Hydrogenophaga pseudoflava based on sustainable raw materials. This strategy provides for increased cost efficiency in PHA production and in enhanced material quality.Material and Methods: As a particularity, production of these poly(3-hydroxybutyrate-co-3- hydroxyvalerate copolyesters was based on a novel substrate/co-substrate combination: whey permeate from dairy industry, on the one hand, acted as substrate for biomass and 3HB biosynthesis; on the other hand, levulinic acid, accessible from various renewable resources, was used as 3HV-related precursor compound. The experiments were carried out on shaking flask scale using defined nutrient media.Results and Conclusion: Applied during nutritionally balanced growth of H. pseudoflava, levulinicacid displays drastic growth inhibition at rather low concentrations of 0.2 g l-1 (growth inhibition constant Ki = 0.032, which suggests the careful supply of this compound in the first phase of cultivation. Under nitrogen-free cultivation conditions, inhibition of the strain´s metabolism by levulinic acid was less pronounced. Here, poly(3-hydroxybutyrate-co- 3-hydroxyvalerate concentrations up to 4.2 g l-1 and volumetric poly(3-hydroxybutyrate-co-3- hydroxyvalerate productivities up to 0.06 g l-1 h -1 were achieved in dependence on the precursor supply. Investigating poly(3-hydroxybutyrate-co-3-hydroxyvalerate composition in setups supplied with differently composed whey/levulinic acid mixtures revealed 3- hydroxyvalerate fractions in the polymer between 0 and 0.6 mol mol-1 . This study successfully demonstrates the feasibility of combined utilization of different waste- and by-products from food industry and agriculture for generation of value-added 2nd generation biopolymers. Conflict of interest: The authors

  15. Molecular Structure of WlbB, a Bacterial N-Acetyltransferase Involved in the Biosynthesis of 2,3-Diacetamido-2,3-dideoxy-d-mannuronic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Thoden, James B.; Holden, Hazel M. (UW)

    2010-09-08

    The pathogenic bacteria Pseudomonas aeruginosa and Bordetella pertussis contain in their outer membranes the rare sugar 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid. Five enzymes are required for the biosynthesis of this sugar starting from UDP-N-acetylglucosamine. One of these, referred to as WlbB, is an N-acetyltransferase that converts UDP-2-acetamido-3-amino-2,3-dideoxy-D-glucuronic acid (UDP-GlcNAc3NA) to UDP-2,3-diacetamido-2,3-dideoxy-D-glucuronic acid (UDP-GlcNAc3NAcA). Here we report the three-dimensional structure of WlbB from Bordetella petrii. For this analysis, two ternary structures were determined to 1.43 {angstrom} resolution: one in which the protein was complexed with acetyl-CoA and UDP and the second in which the protein contained bound CoA and UDP-GlcNAc3NA. WlbB adopts a trimeric quaternary structure and belongs to the L{beta}H superfamily of N-acyltransferases. Each subunit contains 27 {beta}-strands, 23 of which form the canonical left-handed {beta}-helix. There are only two hydrogen bonds that occur between the protein and the GlcNAc3NA moiety, one between O{sup {delta}1} of Asn 84 and the sugar C-3{prime} amino group and the second between the backbone amide group of Arg 94 and the sugar C-5{prime} carboxylate. The sugar C-3{prime} amino group is ideally positioned in the active site to attack the si face of acetyl-CoA. Given that there are no protein side chains that can function as general bases within the GlcNAc3NA binding pocket, a reaction mechanism is proposed for WlbB whereby the sulfur of CoA ultimately functions as the proton acceptor required for catalysis.

  16. Resin composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Peutzfeldt, Anne; Lussi, Adrian

    2014-01-01

    OBJECTIVE: To investigate how the modulus of elasticity of resin composites influences marginal quality in restorations submitted to thermocyclic and mechanical loading. METHODS: Charisma, Filtek Supreme XTE and Grandio were selected as they were found to possess different moduli of elasticity...... of resin composite (p=0.81) on the quality of dentine margins was observed, before or after loading. Deterioration of all margins was evident after loading (p....008). CONCLUSIONS: The resin composite with the highest modulus of elasticity resulted in the highest number of gap-free enamel margins but with an increased incidence of paramarginal enamel fractures. CLINICAL SIGNIFICANCE: The results from this study suggest that the marginal quality of restorations can...

  17. Biosynthesis of Germacrene A Carboxylic Acid in Chicory Roots. Demonstration of a Cytochrome P450 (+)-Germacrene A Hydroxylase and NADP+-Dependent Sesquiterpenoid Dehydrogenase(s) Involved in Sesquiterpene Lactone Biosynthesis

    NARCIS (Netherlands)

    Kraker, de J.W.; Franssen, M.C.R.; Dalm, M.C.F.; Groot, de Æ.; Bouwmeester, H.J.

    2001-01-01

    Sprouts of chicory (Cichorium intybus), a vegetable grown in the dark, have a slightly bitter taste associated with the presence of guaianolides, eudesmanolides, and germacranolides. The committed step in the biosynthesis of these compounds is catalyzed by a ( )-germacrene A synthase. Formation of

  18. Endogenous cytokinins, auxins and abscisic acid in Ulva fasciata (Chlorophyta) and Dictyota humifusa (Phaeophyta): towards understanding their biosynthesis and homoeostasis

    Czech Academy of Sciences Publication Activity Database

    Stirk, W.A.; Novák, Ondřej; Hradecká, Veronika; Pěnčík, Aleš; Rolčík, Jakub; Strnad, Miroslav; van Staden, J.

    2009-01-01

    Roč. 44, č. 2 (2009), s. 231-240 ISSN 0967-0262 R&D Projects: GA ČR GA206/05/0894 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * auxins * cytokinins Subject RIV: BO - Biophysics Impact factor: 1.556, year: 2009 www.informaworld.com/smpp/content~content=a911046981

  19. Orchestrating the Biosynthesis of an Unnatural Pyrrolysine Amino Acid for Its Direct Incorporation into Proteins Inside Living Cells

    Czech Academy of Sciences Publication Activity Database

    Ehrlich, M.; Gattner, M. J.; Viverge, B.; Bretzler, J.; Eisen, D.; Stadlmeier, M.; Vrábel, Milan; Carell, T.

    2015-01-01

    Roč. 21, č. 21 (2015), s. 7701-7704 ISSN 0947-6539 Institutional support: RVO:61388963 Keywords : amber suppression * bioorganic chemistry * pyrrolysine * synthetic biology * unnatural amino acid Subject RIV: CC - Organic Chemistry Impact factor: 5.771, year: 2015

  20. Cooperative functioning between phenylalanine ammonia lyase and isochorishmate synthase activities contributes to salicylic acid biosynthesis in soybean

    Science.gov (United States)

    Salicylic acid (SA), an essential regulator of plant defense, is derived from chorismate via either the phenylalanine ammonia lyase (PAL), or the isochorishmate synthase (ICS) catalyzed steps. The ICS pathway is thought to be the primary contributor of defense-related SA, at least in Arabidopsis. We...

  1. Enrichment of Gamma-Aminobutyric Acid in Bean Sprouts: Exploring Biosynthesis of Plant Metabolite Using Common Household Reagents

    Science.gov (United States)

    Rojanarata, Theerasak; Plianwong, Samarwadee; Opanasopit, Praneet; Ngawhirunpat, Tanasait

    2018-01-01

    The enrichment of plant foods with gamma-aminobutyric acid (GABA) is currently an interesting issue in the field of nutraceuticals and can be used as an experiment for upper-division undergraduate students. Here, an interdisciplinary hands-on experiment to produce GABA-enriched mung bean sprouts using common household reagents is described. Based…

  2. Characterization of a membrane-bound C-glucosyltransferase responsible for carminic acid biosynthesis in Dactylopius coccus Costa.

    Science.gov (United States)

    Kannangara, Rubini; Siukstaite, Lina; Borch-Jensen, Jonas; Madsen, Bjørn; Kongstad, Kenneth T; Staerk, Dan; Bennedsen, Mads; Okkels, Finn T; Rasmussen, Silas A; Larsen, Thomas O; Frandsen, Rasmus J N; Møller, Birger Lindberg

    2017-12-07

    Carminic acid, a glucosylated anthraquinone found in scale insects like Dactylopius coccus, has since ancient times been used as a red colorant in various applications. Here we show that a membrane-bound C-glucosyltransferase, isolated from D. coccus and designated DcUGT2, catalyzes the glucosylation of flavokermesic acid and kermesic acid into their respective C-glucosides dcII and carminic acid. DcUGT2 is predicted to be a type I integral endoplasmic reticulum (ER) membrane protein, containing a cleavable N-terminal signal peptide and a C-terminal transmembrane helix that anchors the protein to the ER, followed by a short cytoplasmic tail. DcUGT2 is found to be heavily glycosylated. Truncated DcUGT2 proteins synthesized in yeast indicate the presence of an internal ER-targeting signal. The cleavable N-terminal signal peptide is shown to be essential for the activity of DcUGT2, whereas the transmembrane helix/cytoplasmic domains, although important, are not crucial for its catalytic function.

  3. Variability and determinants of wood dust and resin acid exposure during wood pellet production: measurement strategies and bias in assessing exposure-response relationships.

    Science.gov (United States)

    Hagström, Katja; Lundholm, Cecilia; Eriksson, Kare; Liljelind, Ingrid

    2008-11-01

    Production of wood pellets is a relatively new and expanding industry in which the exposure profiles differ from those in other wood-processing industries like carpentries and sawmills where there are lower levels of wood dust. Sixty-eight personal exposure measurements of wood dust (inhalable and total dust) and resin acids were collected for 44 participants at four production plants located in Sweden. Results were used to estimate within- and between-worker variability and to identify uniformly exposed groups and determinants of exposure. In addition, overexposure, whether the risk of the long-term mean exposure of a randomly selected worker exceeding the occupational exposure limit is acceptably low, was calculated as well as the underestimation of the exposure-response relationship (attenuation). Greater variability in exposure between work shifts than between workers was observed with the within-worker variation accounting for 57-99% of the total variance in the individual-based model. Several uniformly exposed groups were detected but were mostly associated with a between-worker variation of zero which is an underestimation of the between-worker variation but an indication of uniformly exposed groups. Cleaning was identified as a work task that increases exposure slightly; so reducing workers' exposure during this operation is advisable. The levels of wood dust were high and were found to pose unacceptable risks of overexposure at all plants for inhalable dust and at three out of four plants for total dust. These findings show that exposure to dust needs to be reduced in this industry. For resin acids, the exposure was classed as acceptable at all plants. According to an individual-based model constructed from the data, the level of attenuation was high, and thus there would be substantial bias in derived dose-response relationships.

  4. Auxin biosynthesis and storage forms

    Science.gov (United States)

    Strader, Lucia C.

    2013-01-01

    The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development. PMID:23580748

  5. Odd Chain Fatty Acids, New Insights of the Relationship Between the Gut Microbiota, Dietary Intake, Biosynthesis and Glucose Intolerance

    Czech Academy of Sciences Publication Activity Database

    Jenkins, B.J.; Seyssel, K.; Chiu, S.; Pan, P.-H.; Lin, S.-Y.; Stanley, E.; Ament, Z.; West, J.A.; Summerhill, K.; Griffin, J.L.; Vetter, W.; Autio, K.J.; Hiltunen, K.; Hazebrouck, S.; Štěpánková, Renata; Chen, C.-J.; Alligier, M.; Laville, M.; Moore, M.; Kraft, G.; Cherrington, A.; King, S.; Krauss, R.M.; de Schryver, E.; Van Veldhoven, P.P.; Ronis, M.; Koulman, A.

    2017-01-01

    Roč. 7, MAR 23 (2017), s. 1-8, č. článku 44845. ISSN 2045-2322 R&D Projects: GA ČR(CZ) GA15-09518S; GA ČR(CZ) GA16-06326S Institutional support: RVO:61388971 Keywords : fatty acids * gut * microbiota Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.259, year: 2016

  6. Hepatic fatty acid biosynthesis is more responsive to protein than carbohydrate in rainbow trout during acute stimulations.

    Science.gov (United States)

    Dai, Weiwei; Panserat, Stéphane; Kaushik, Sadasivam; Terrier, Frédéric; Plagnes-Juan, Elisabeth; Seiliez, Iban; Skiba-Cassy, Sandrine

    2016-01-01

    The link between dietary carbohydrate/protein and de novo lipogenesis (DNL) remains debatable in carnivorous fish. We aimed to evaluate and compare the response of hepatic lipogenic gene expression to dietary carbohydrate intake/glucose and dietary protein intake/amino acids (AAs) during acute stimulations using both in vivo and in vitro approaches. For the in vivo trial, three different diets and a controlled-feeding method were employed to supply fixed amount of dietary protein or carbohydrate in a single meal; for the in vitro trial, primary hepatocytes were stimulated with a low or high level of glucose (3 mM or 20 mM) and a low or high level of AAs (one-fold or four-fold concentrated AAs). In vitro data showed that a high level of AAs upregulated the expression of enzymes involved in DNL [fatty acid synthase (FAS) and ATP citrate lyase (ACLY)], lipid bioconversion [elongation of very long chain fatty acids like-5 (Elovl5), Elovl2, Δ6 fatty acyl desaturase (D6D) and stearoyl-CoA desaturase-1 (SCD1)], NADPH production [glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME)], and transcriptional factor sterol regulatory element binding protein 1-like, while a high level of glucose only elevated the expression of ME. Data in trout liver also showed that high dietary protein intake induced higher lipogenic gene expression (FAS, ACLY, and Elovl2) regardless of dietary carbohydrate intake, while high carbohydrate intake markedly suppressed the expression of acetyl-CoA carboxylase (ACC) and Elovl5. Overall, we conclude that, unlike rodents or humans, hepatic fatty acid biosynthetic gene expression in rainbow trout is more responsive to dietary protein intake/AAs than dietary carbohydrate intake/glucose during acute stimulations. This discrepancy probably represents one important physiological and metabolic difference between carnivores and omnivores. Copyright © 2016 the American Physiological Society.

  7. DNA Methylation Influences Chlorogenic Acid Biosynthesis in Lonicera japonica by Mediating LjbZIP8 to Regulate Phenylalanine Ammonia-Lyase 2 Expression

    Directory of Open Access Journals (Sweden)

    Liangping Zha

    2017-07-01

    Full Text Available The content of active compounds differ in buds and flowers of Lonicera japonica (FLJ and L. japonica var. chinensis (rFLJ. Chlorogenic acid (CGAs were major active compounds of L. japonica and regarded as measurements for quality evaluation. However, little is known concerning the formation of active compounds at the molecular level. We quantified the major CGAs in FLJ and rFLJ, and found the concentrations of CGAs were higher in the buds of rFLJ than those of FLJ. Further analysis of CpG methylation of CGAs biosynthesis genes showed differences between FLJ and rFLJ in the 5′-UTR of phenylalanine ammonia-lyase 2 (PAL2. We identified 11 LjbZIP proteins and 24 rLjbZIP proteins with conserved basic leucine zipper domains, subcellular localization, and electrophoretic mobility shift assay showed that the transcription factor LjbZIP8 is a nuclear-localized protein that specifically binds to the G-box element of the LjPAL2 5′-UTR. Additionally, a transactivation assay and LjbZIP8 overexpression in transgenic tobacco indicated that LjbZIP8 could function as a repressor of transcription. Finally, treatment with 5-azacytidine decreased the transcription level of LjPAL2 and CGAs content in FLJ leaves. These results raise the possibility that DNA methylation might influence the recruitment of LjbZIP8, regulating PAL2 expression level and CGAs content in L. japonica.

  8. Glyphosate’s Suppression of Cytochrome P450 Enzymes and Amino Acid Biosynthesis by the Gut Microbiome: Pathways to Modern Diseases

    Directory of Open Access Journals (Sweden)

    Anthony Samsel

    2013-04-01

    Full Text Available Glyphosate, the active ingredient in Roundup®, is the most popular herbicide used worldwide. The industry asserts it is minimally toxic to humans, but here we argue otherwise. Residues are found in the main foods of the Western diet, comprised primarily of sugar, corn, soy and wheat. Glyphosate's inhibition of cytochrome P450 (CYP enzymes is an overlooked component of its toxicity to mammals. CYP enzymes play crucial roles in biology, one of which is to detoxify xenobiotics. Thus, glyphosate enhances the damaging effects of other food borne chemical residues and environmental toxins. Negative impact on the body is insidious and manifests slowly over time as inflammation damages cellular systems throughout the body. Here, we show how interference with CYP enzymes acts synergistically with disruption of the biosynthesis of aromatic amino acids by gut bacteria, as well as impairment in serum sulfate transport. Consequences are most of the diseases and conditions associated with a Western diet, which include gastrointestinal disorders, obesity, diabetes, heart disease, depression, autism, infertility, cancer and Alzheimer’s disease. We explain the documented effects of glyphosate and its ability to induce disease, and we show that glyphosate is the “textbook example” of exogenous semiotic entropy: the disruption of homeostasis by environmental toxins.

  9. AglC and AglK are involved in biosynthesis and attachment of diacetylated glucuronic acid to the N-glycan in Methanococcus voltae.

    Science.gov (United States)

    Chaban, Bonnie; Logan, Susan M; Kelly, John F; Jarrell, Ken F

    2009-01-01

    Recent advances in the field of prokaryotic N-glycosylation have established a foundation for the pathways and proteins involved in this important posttranslational protein modification process. To continue the study of the Methanococcus voltae N-glycosylation pathway, characteristics of known eukaryotic, bacterial, and archaeal proteins involved in the N-glycosylation process were examined and used to select candidate M. voltae genes for investigation as potential glycosyl transferase and flippase components. The targeted genes were knocked out via linear gene replacement, and the resulting effects on N-glycan assembly were identified through flagellin and surface (S) layer protein glycosylation defects. This study reports the finding that deletion of two putative M. voltae glycosyl transferase genes, designated aglC (for archaeal glycosylation) and aglK, interfered with proper N-glycosylation. This resulted in flagellin and S-layer proteins with significantly reduced apparent molecular masses, loss of flagellar assembly, and absence of glycan attachment. Given previous knowledge of both the N-glycosylation pathway in M. voltae and the general characteristics of N-glycosylation components, it appears that AglC and AglK are involved in the biosynthesis or transfer of diacetylated glucuronic acid within the glycan structure. In addition, a knockout of the putative flippase candidate gene (Mv891) had no effect on N-glycosylation but did result in the production of giant cells with diameters three to four times that of wild-type cells.

  10. Salicylic acid-induced changes in physiological parameters and genes of the flavonoid biosynthesis pathway in Artemisia vulgaris and Dendranthema nankingense during aphid feeding.

    Science.gov (United States)

    Sun, Y; Xia, X L; Jiang, J F; Chen, S M; Chen, F D; Lv, G S

    2016-02-19

    Phloem-feeding aphids cause serious damage to plants. The mechanisms of plant-aphid interactions are only partially understood and involve multiple pathways, including phytohormones. In order to investigate whether salicylic acid (SA) is involved and how it plays a part in the defense response to the aphid Macrosiphoniella sanbourni, physiological changes and gene expression profiles in response to aphid inoculation with or without SA pretreatment were compared between the aphid-resistant Artemisia vulgaris 'Variegata' and the susceptible chrysanthemum, Dendranthema nankingense. Changes in levels of reactive oxygen species, malondialdehyde (MDA), and flavonoids, and in the expression of genes involved in flavonoid biosynthesis, including PAL (phenylalanine ammonia-lyase), CHS (chalcone synthase), CHI (chalcone isomerase), F3H (flavanone 3-hydroxylase), F3'H (flavanone 3'-hydroxylase), and DFR (dihydroflavonol reductase), were investigated. Levels of hydrogen peroxide, superoxide anions, MDA, and flavonoids, and their related gene expression, increased after aphid infestation and SA pretreatment followed by aphid infestation; the aphid-resistant A. vulgaris exhibited a more rapid response than the aphid-susceptible D. nankingense to SA treatment and aphid infestation. Taken together, our results suggest that SA could be used to increase aphid resistance in the chrysanthemum.

  11. Overexpression of EsMcsu1 from the halophytic plant Eutrema salsugineum promotes abscisic acid biosynthesis and increases drought resistance in alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Zhou, C; Ma, Z Y; Zhu, L; Guo, J S; Zhu, J; Wang, J F

    2015-12-17

    The stress phytohormone abscisic acid (ABA) plays pivotal roles in plants' adaptive responses to adverse environments. Molybdenum cofactor sulfurases influence aldehyde oxidase activity and ABA biosynthesis. In this study, we isolated a novel EsMcsu1 gene encoding a molybdenum cofactor sulfurase from Eutrema salsugineum. EsMcus1 transcriptional patterns varied between organs, and its expression was significantly upregulated by abiotic stress or ABA treatment. Alfalfa plants that overexpressed EsMcsu1 had a higher ABA content than wild-type (WT) plants under drought stress conditions. Furthermore, levels of reactive oxygen species (ROS), ion leakage, and malondialdehyde were lower in the transgenic plants than in the WT plants after drought treatment, suggesting that the transgenic plants experienced less ROS-mediated damage. However, the expression of several stress-responsive genes, antioxidant enzyme activity, and osmolyte (proline and total soluble sugar) levels in the transgenic plants were higher than those in the WT plants after drought treatment. Therefore, EsMcsu1 overexpression improved drought tolerance in alfalfa plants by activating a series of ABA-mediated stress responses.

  12. Direct Assay of δ-Aminolevulinic Acid Dehydratase in Heme Biosynthesis for the Detection of Porphyrias by Tandem Mass Spectrometry

    Science.gov (United States)

    Choiniere, John R.; Scott, C. Ronald; Gelb, Michael H.; Tureček, František

    2010-01-01

    We report a new assay of human δ-aminolevulinic acid dehydratase (ALAD), an enzyme converting δ-aminolevulinic acid (ALA) into porphobilinogen. The assay is developed for use in the clinical diagnosis of δ-aminolevulinic acid dehydratase-deficient porphyria, a rare enzymatic deficiency of the heme biosynthetic pathway. The assay involves the incubation of erythrocyte lysate with the natural substrate, ALA, followed by quantitative in situ conversion of porphobilinogen to its butyramide, and liquid-liquid extraction into a mass spectrometer-friendly solvent. Quantitation of the butyrylated porphobilinogen is done by electrospray ionization tandem mass spectrometry, using a deuterium labeled internal standard. The assay stays well within the range wherein ALAD activity is linear with time. The Km of ALAD for ALA was measured as 333 μM, and the Vmax was 19.3 μM/hr. Average enzyme activity among a random sample of 36 anonymous individuals was 277 μmol/L erythrocyte lysate/hour with a standard deviation of 90 μmol/L erythrocyte lysate/hour. The tandem mass spectrometric assay should easily detect the enzyme deficiency, which causes a reduction of activity by 95–99%. The assay shows good reproducibility, low background, requires a simple workup, and uses a commercially available substrate. PMID:20583792

  13. Direct assay of delta-aminolevulinic acid dehydratase in heme biosynthesis for the detection of porphyrias by tandem mass spectrometry.

    Science.gov (United States)

    Choiniere, John R; Scott, C Ronald; Gelb, Michael H; Turecek, Frantisek

    2010-08-01

    We report a new assay of human delta-aminolevulinic acid dehydratase (ALAD), an enzyme converting delta-aminolevulinic acid (ALA) into porphobilinogen. The assay is developed for use in the clinical diagnosis of delta-aminolevulinic acid dehydratase-deficient porphyria, a rare enzymatic deficiency of the heme biosynthetic pathway. The assay involves the incubation of erythrocyte lysate with the natural substrate, ALA, followed by quantitative in situ conversion of porphobilinogen to its butyramide, and liquid-liquid extraction into a mass spectrometer-friendly solvent. Quantitation of the butyrylated porphobilinogen is done by electrospray ionization tandem mass spectrometry, using a deuterium labeled internal standard. The assay stays well within the range wherein ALAD activity is linear with time. The K(m) of ALAD for ALA was measured as 333 microM, and the V(max) was 19.3 microM/h. Average enzyme activity among a random sample of 36 anonymous individuals was 277 micromol/L erythrocyte lysate/hour with a standard deviation of 90 micromol/L erythrocyte lysate/hour. The tandem mass spectrometric assay should easily detect the enzyme deficiency, which causes a reduction of activity by 95-99%. The assay shows good reproducibility and low background, requires a simple workup, and uses a commercially available substrate.