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Sample records for acid malic acid

  1. 21 CFR 184.1069 - Malic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Malic acid. 184.1069 Section 184.1069 Food and....1069 Malic acid. (a) Malic acid (C4H6O5, CAS Reg. No. of L-form 97-67-6, CAS Reg. No. of DL-form 617-48-1) is the common name for 1-hydroxy-1, 2-ethanedicarboxylic acid. L (+) malic acid, referred to as...

  2. 21 CFR 582.1069 - Malic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Malic acid. 582.1069 Section 582.1069 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1069 Malic acid. (a) Product. Malic acid. (b) Conditions of use. This substance is generally...

  3. 21 CFR 582.1069 - Malic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Malic acid. 582.1069 Section 582.1069 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1069 Malic acid. (a) Product. Malic acid. (b) Conditions of use. This substance is generally...

  4. 21 CFR 582.1069 - Malic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Malic acid. 582.1069 Section 582.1069 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1069 Malic acid. (a) Product. Malic acid. (b) Conditions of use. This substance is generally...

  5. 21 CFR 582.1069 - Malic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Malic acid. 582.1069 Section 582.1069 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1069 Malic acid. (a) Product. Malic acid. (b) Conditions of use. This substance is generally...

  6. 21 CFR 582.1069 - Malic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Malic acid. 582.1069 Section 582.1069 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1069 Malic acid. (a) Product. Malic acid. (b) Conditions of use. This substance is generally...

  7. 21 CFR 184.1069 - Malic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Malic acid. 184.1069 Section 184.1069 Food and... Substances Affirmed as GRAS § 184.1069 Malic acid. (a) Malic acid (C4H6O5, CAS Reg. No. of L-form 97-67-6, CAS Reg. No. of DL-form 617-48-1) is the common name for 1-hydroxy-1, 2-ethanedicarboxylic acid....

  8. 21 CFR 184.1069 - Malic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Malic acid. 184.1069 Section 184.1069 Food and... Substances Affirmed as GRAS § 184.1069 Malic acid. (a) Malic acid (C4H6O5, CAS Reg. No. of L-form 97-67-6, CAS Reg. No. of DL-form 617-48-1) is the common name for 1-hydroxy-1, 2-ethanedicarboxylic acid....

  9. 21 CFR 184.1069 - Malic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Malic acid. 184.1069 Section 184.1069 Food and... Substances Affirmed as GRAS § 184.1069 Malic acid. (a) Malic acid (C4H6O5, CAS Reg. No. of L-form 97-67-6, CAS Reg. No. of DL-form 617-48-1) is the common name for 1-hydroxy-1, 2-ethanedicarboxylic acid....

  10. 21 CFR 184.1069 - Malic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Malic acid. 184.1069 Section 184.1069 Food and... Substances Affirmed as GRAS § 184.1069 Malic acid. (a) Malic acid (C4H6O5, CAS Reg. No. of L-form 97-67-6, CAS Reg. No. of DL-form 617-48-1) is the common name for 1-hydroxy-1, 2-ethanedicarboxylic acid....

  11. Fungal biotransformation of crude glycerol into malic acid.

    PubMed

    West, Thomas P

    2015-01-01

    Malic acid production from the biodiesel coproduct crude glycerol by Aspergillus niger ATCC 9142, ATCC 10577 and ATCC 12846 was observed to occur with the highest malic acid level acid being produced by A. niger ATCC 12846. Fungal biomass production from crude glycerol was similar, but ATCC 10577 produced the highest biomass. Fungal biotransformation of crude glycerol into the commercially valuable organic acid malic acid appeared feasible.

  12. Malic acid production from thin stillage by Aspergillus species.

    PubMed

    West, Thomas P

    2011-12-01

    The ability of Aspergillus strains to utilize thin stillage to produce malic acid was compared. The highest malic acid was produced by Aspergillus niger ATCC 9142 at 17 g l(-1). Biomass production from thin stillage was similar with all strains but ATCC 10577 was the highest at 19 g l(-1). The highest malic acid yield (0.8 g g(-1)) was with A. niger ATCC 9142 and ATCC 10577 on the stillage. Thus, thin stillage has the potential to act as a substrate for the commercial production of food-grade malic acid by the A. niger strains.

  13. γ-Irradiation of malic acid in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Negron-Mendoza, Alicia; Graff, Rebecca L.; Ponnamperuma, Cyril

    1980-12-01

    The γ-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the non-volatile products. Thin layer chromotography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the γ-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  14. Sequential Mixed Cultures: From Syngas to Malic Acid.

    PubMed

    Oswald, Florian; Dörsam, Stefan; Veith, Nicolas; Zwick, Michaela; Neumann, Anke; Ochsenreither, Katrin; Syldatk, Christoph

    2016-01-01

    Synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. Suffering from energetic limitations, yields of C4-molecules produced by syngas fermentation are quite low compared with ABE fermentation using sugars as a substrate. On the other hand, fungal production of malic acid has high yields of product per gram metabolized substrate but is currently limited to sugar containing substrates. In this study, it was possible to show that Aspergilus oryzae is able to produce malic acid using acetate as sole carbon source which is a main product of acetogenic syngas fermentation. Bioreactor cultivations were conducted in 2.5 L stirred tank reactors. During the syngas fermentation part of the sequential mixed culture, Clostridium ljungdahlii was grown in modified Tanner medium and sparged with 20 mL/min of artificial syngas mimicking a composition of clean syngas from entrained bed gasification of straw (32.5 vol-% CO, 32.5 vol-% H2, 16 vol-% CO2, and 19 vol-% N2) using a microsparger. Syngas consumption was monitored via automated gas chromatographic measurement of the off-gas. For the fungal fermentation part gas sparging was switched to 0.6 L/min of air and a standard sparger. Ammonia content of medium for syngas fermentation was reduced to 0.33 g/L NH4Cl to meet the requirements for fungal production of dicarboxylic acids. Malic acid production performance of A. oryzae in organic acid production medium and syngas medium with acetate as sole carbon source was verified and gave YP∕S values of 0.28 g/g and 0.37 g/g respectively. Growth and acetate formation of C. ljungdahlii during syngas fermentation were not affected by the reduced ammonia content and 66 % of the consumed syngas was converted to acetate. The overall conversion

  15. Sequential Mixed Cultures: From Syngas to Malic Acid.

    PubMed

    Oswald, Florian; Dörsam, Stefan; Veith, Nicolas; Zwick, Michaela; Neumann, Anke; Ochsenreither, Katrin; Syldatk, Christoph

    2016-01-01

    Synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. Suffering from energetic limitations, yields of C4-molecules produced by syngas fermentation are quite low compared with ABE fermentation using sugars as a substrate. On the other hand, fungal production of malic acid has high yields of product per gram metabolized substrate but is currently limited to sugar containing substrates. In this study, it was possible to show that Aspergilus oryzae is able to produce malic acid using acetate as sole carbon source which is a main product of acetogenic syngas fermentation. Bioreactor cultivations were conducted in 2.5 L stirred tank reactors. During the syngas fermentation part of the sequential mixed culture, Clostridium ljungdahlii was grown in modified Tanner medium and sparged with 20 mL/min of artificial syngas mimicking a composition of clean syngas from entrained bed gasification of straw (32.5 vol-% CO, 32.5 vol-% H2, 16 vol-% CO2, and 19 vol-% N2) using a microsparger. Syngas consumption was monitored via automated gas chromatographic measurement of the off-gas. For the fungal fermentation part gas sparging was switched to 0.6 L/min of air and a standard sparger. Ammonia content of medium for syngas fermentation was reduced to 0.33 g/L NH4Cl to meet the requirements for fungal production of dicarboxylic acids. Malic acid production performance of A. oryzae in organic acid production medium and syngas medium with acetate as sole carbon source was verified and gave YP∕S values of 0.28 g/g and 0.37 g/g respectively. Growth and acetate formation of C. ljungdahlii during syngas fermentation were not affected by the reduced ammonia content and 66 % of the consumed syngas was converted to acetate. The overall conversion

  16. Sequential Mixed Cultures: From Syngas to Malic Acid

    PubMed Central

    Oswald, Florian; Dörsam, Stefan; Veith, Nicolas; Zwick, Michaela; Neumann, Anke; Ochsenreither, Katrin; Syldatk, Christoph

    2016-01-01

    Synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. Suffering from energetic limitations, yields of C4-molecules produced by syngas fermentation are quite low compared with ABE fermentation using sugars as a substrate. On the other hand, fungal production of malic acid has high yields of product per gram metabolized substrate but is currently limited to sugar containing substrates. In this study, it was possible to show that Aspergilus oryzae is able to produce malic acid using acetate as sole carbon source which is a main product of acetogenic syngas fermentation. Bioreactor cultivations were conducted in 2.5 L stirred tank reactors. During the syngas fermentation part of the sequential mixed culture, Clostridium ljungdahlii was grown in modified Tanner medium and sparged with 20 mL/min of artificial syngas mimicking a composition of clean syngas from entrained bed gasification of straw (32.5 vol-% CO, 32.5 vol-% H2, 16 vol-% CO2, and 19 vol-% N2) using a microsparger. Syngas consumption was monitored via automated gas chromatographic measurement of the off-gas. For the fungal fermentation part gas sparging was switched to 0.6 L/min of air and a standard sparger. Ammonia content of medium for syngas fermentation was reduced to 0.33 g/L NH4Cl to meet the requirements for fungal production of dicarboxylic acids. Malic acid production performance of A. oryzae in organic acid production medium and syngas medium with acetate as sole carbon source was verified and gave YP∕S values of 0.28 g/g and 0.37 g/g respectively. Growth and acetate formation of C. ljungdahlii during syngas fermentation were not affected by the reduced ammonia content and 66 % of the consumed syngas was converted to acetate. The overall conversion

  17. Method for the isolation of citric acid and malic acid in Japanese apricot liqueur for carbon stable isotope analysis.

    PubMed

    Akamatsu, Fumikazu; Hashiguchi, Tomokazu; Hisatsune, Yuri; Oe, Takaaki; Kawao, Takafumi; Fujii, Tsutomu

    2017-02-15

    A method for detecting the undeclared addition of acidic ingredients is required to control the authenticity of Japanese apricot liqueur. We developed an analytical procedure that minimizes carbon isotope discrimination for measurement of the δ(13)C values of citric and malic acid isolated from Japanese apricot liqueur. Our results demonstrated that freeze-drying is preferable to nitrogen spray-drying, because it does not significantly affect the δ(13)C values of citric acid and results in smaller isotope discrimination for malic acid. Both 0.1% formic acid and 0.2% phosphoric acid are acceptable HPLC mobile phases for the isolation of citric and malic acid, although the δ(13)C values of malic acid exhibited relatively large variation compared with citric acid following isolation using either mobile phase. The developed procedure allows precise δ(13)C measurements of citric and malic acid isolated from Japanese apricot liqueur. PMID:27664615

  18. Method for the isolation of citric acid and malic acid in Japanese apricot liqueur for carbon stable isotope analysis.

    PubMed

    Akamatsu, Fumikazu; Hashiguchi, Tomokazu; Hisatsune, Yuri; Oe, Takaaki; Kawao, Takafumi; Fujii, Tsutomu

    2017-02-15

    A method for detecting the undeclared addition of acidic ingredients is required to control the authenticity of Japanese apricot liqueur. We developed an analytical procedure that minimizes carbon isotope discrimination for measurement of the δ(13)C values of citric and malic acid isolated from Japanese apricot liqueur. Our results demonstrated that freeze-drying is preferable to nitrogen spray-drying, because it does not significantly affect the δ(13)C values of citric acid and results in smaller isotope discrimination for malic acid. Both 0.1% formic acid and 0.2% phosphoric acid are acceptable HPLC mobile phases for the isolation of citric and malic acid, although the δ(13)C values of malic acid exhibited relatively large variation compared with citric acid following isolation using either mobile phase. The developed procedure allows precise δ(13)C measurements of citric and malic acid isolated from Japanese apricot liqueur.

  19. Optimization of L-malic acid production by Aspergillus flavus in a stirred fermentor.

    PubMed

    Battat, E; Peleg, Y; Bercovitz, A; Rokem, J S; Goldberg, I

    1991-05-01

    Effects of various nutritional and environmental factors on the accumulation of organic acids (mainly L-malic acid) by the filamentous fungus Aspergillus flavus were studied in a 16-L stirred fermentor. Improvement of the molar yield (moles acid produced per moles glucose consumed) of L-malic acid was obtained mainly by increasing the agitation rate (to 350 rpm) and the Fe(z+) ion concentration (to 12 mg/L) and by lowering the nitrogen (to 271 mg/L) and phosphate concentrations (to 1.5 mM) in the medium. These changes resulted in molar yields for L-malic acid and total C(4) acids (L-malic, succinic, and fumaric acids) of 128 and 155%, respectively. The high molar yields obtained (above 100%) are additional evidence for the operation of part of the reductive branch of the tricarboxylic acid cycle in L-malic acid accumulation by A. flavus. The fermentation conditions developed using the above mentioned factors and 9% CaCO(3) in the medium resulted in a high concentration (113 g/L L-malic acid from 120 g/L glucose utilized) and a high overall productivity (0.59 g/L h) of L-malic acid. These changes in acid accumulation coincide with increases in the activities of NAD(+)-malate dehydrogenase, fumarase, and citrate synthase.

  20. A simple plate-assay for the screening of L-malic acid producing microorganisms.

    PubMed

    Peleg, Y; Rokem, J S; Goldberg, I

    1990-02-01

    A simple plate-assay has been developed to screen microorganisms for L-malic acid production. Acid producing organisms were identified, after microbial colony growth on media containing glucose or fumaric acid as sole carbons sources, by formation of a dark halo of formazan. The halo was observed when the plate was covered with a soft agar overlay containing NAD(+)-malate dehydrogenase, NAD+, phenazine methosulfate (PMS) and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). The assay developed is simple, specific for L-malic acid and therefore can be used to identify L-malic acid producing filamentous fungi using glucose as carbon source (e.g. Aspergillus strains). The assay is also applicable for screening bacteria with high fumarase activity, able to convert fumaric acid to L-malic acid.

  1. Characteristics of the high malic acid production mechanism in Saccharomyces cerevisiae sake yeast strain No. 28.

    PubMed

    Nakayama, Shunichi; Tabata, Ken; Oba, Takahiro; Kusumoto, Kenichi; Mitsuiki, Shinji; Kadokura, Toshimori; Nakazato, Atsumi

    2012-09-01

    We characterized a high malic acid production mechanism in sake yeast strain No. 28. No considerable differences in the activity of the enzymes that were involved in malic acid synthesis were observed between strain No. 28 and its parent strain, K1001. However, compared with strain K1001, which actively took up rhodamine 123 during staining, the cells of strain No. 28 were only lightly stained, even when cultured in high glucose concentrations. In addition, malic acid production by the respiratory-deficient strain of K1001 was 2.5-fold higher than that of the wild-type K1001 and wild-type No. 28. The findings of this study demonstrated that the high malic acid production by strain No. 28 is attributed to the suppression of mitochondrial activity.

  2. Investigation of malic acid production in Aspergillus oryzae under nitrogen starvation conditions.

    PubMed

    Knuf, Christoph; Nookaew, Intawat; Brown, Stephen H; McCulloch, Michael; Berry, Alan; Nielsen, Jens

    2013-10-01

    Malic acid has great potential for replacing petrochemical building blocks in the future. For this application, high yields, rates, and titers are essential in order to sustain a viable biotechnological production process. Natural high-capacity malic acid producers like the malic acid producer Aspergillus flavus have so far been disqualified because of special growth requirements or the production of mycotoxins. As A. oryzae is a very close relative or even an ecotype of A. flavus, it is likely that its high malic acid production capabilities with a generally regarded as safe (GRAS) status may be combined with already existing large-scale fermentation experience. In order to verify the malic acid production potential, two wild-type strains, NRRL3485 and NRRL3488, were compared in shake flasks. As NRRL3488 showed a volumetric production rate twice as high as that of NRRL3485, this strain was selected for further investigation of the influence of two different nitrogen sources on malic acid secretion. The cultivation in lab-scale fermentors resulted in a higher final titer, 30.27 ± 1.05 g liter(-1), using peptone than the one of 22.27 ± 0.46 g liter(-1) obtained when ammonium was used. Through transcriptome analysis, a binding site similar to the one of the Saccharomyces cerevisiae yeast transcription factor Msn2/4 was identified in the upstream regions of glycolytic genes and the cytosolic malic acid production pathway from pyruvate via oxaloacetate to malate, which suggests that malic acid production is a stress response. Furthermore, the pyruvate carboxylase reaction was identified as a target for metabolic engineering, after it was confirmed to be transcriptionally regulated through the correlation of intracellular fluxes and transcriptional changes.

  3. Physiological characterization of the high malic acid-producing Aspergillus oryzae strain 2103a-68.

    PubMed

    Knuf, Christoph; Nookaew, Intawat; Remmers, Ilse; Khoomrung, Sakda; Brown, Stephen; Berry, Alan; Nielsen, Jens

    2014-04-01

    Malic acid is a C₄ dicarboxylic acid that is currently mainly used in the food and beverages industry as an acidulant. Because of the versatility of the group of C₄ dicarboxylic acids, the chemical industry has a growing interest in this chemical compound. As malic acid will be considered as a bulk chemical, microbial production requires organisms that sustain high rates, yields, and titers. Aspergillus oryzae is mainly known as an industrial enzyme producer, but it was also shown that it has a very competitive natural production capacity for malic acid. Recently, an engineered A. oryzae strain, 2103a-68, was presented which overexpressed pyruvate carboxylase, malate dehydrogenase, and a malic acid transporter. In this work, we report a detailed characterization of this strain including detailed rates and yields under malic acid production conditions. Furthermore, transcript levels of the genes of interest and corresponding enzyme activities were measured. On glucose as carbon source, 2103a-68 was able to secrete malic acid at a maximum specific production rate during stationary phase of 1.87 mmol (g dry weight (DW))⁻¹ h⁻¹ and with a yield of 1.49 mol mol⁻¹. Intracellular fluxes were obtained using ¹³C flux analysis during exponential growth, supporting the success of the metabolic engineering strategy of increasing flux through the reductive cytosolic tricarboxylic acid (rTCA) branch. Additional cultivations using xylose and a glucose/xylose mixture demonstrated that A. oryzae is able to efficiently metabolize pentoses and hexoses to produce malic acid at high titers, rates, and yields.

  4. The Path of Carbon in Photosynthesis VIII. The Role of Malic Acid

    DOE R&D Accomplishments Database

    Bassham, James A.; Benson, Andrew A.; Calvin, Melvin

    1950-01-25

    Malonate has been found to inhibit the formation of malic acid during short periods of photosynthesis with radioactive carbon dioxide. This result, together with studies which show the photosynthetic cycle to be operating normally at the same time, indicates that malic acid is not an intermediate in photosynthesis but is probably closely related to some intermediate of the cycle. Absence of labeled succinic and fumaric acids in these experiments, in addition to the failure of malonate to inhibit photosynthesis, precludes the participation of these acids as intermediates in photosynthesis.

  5. Requirement of the Lactobacillus casei MaeKR two-component system for L-malic acid utilization via a malic enzyme pathway.

    PubMed

    Landete, José María; García-Haro, Luisa; Blasco, Amalia; Manzanares, Paloma; Berbegal, Carmen; Monedero, Vicente; Zúñiga, Manuel

    2010-01-01

    Lactobacillus casei can metabolize L-malic acid via malolactic enzyme (malolactic fermentation [MLF]) or malic enzyme (ME). Whereas utilization of L-malic acid via MLF does not support growth, the ME pathway enables L. casei to grow on L-malic acid. In this work, we have identified in the genomes of L. casei strains BL23 and ATCC 334 a cluster consisting of two diverging operons, maePE and maeKR, encoding a putative malate transporter (maeP), an ME (maeE), and a two-component (TC) system belonging to the citrate family (maeK and maeR). Homologous clusters were identified in Enterococcus faecalis, Streptococcus agalactiae, Streptococcus pyogenes, and Streptococcus uberis. Our results show that ME is essential for L-malic acid utilization in L. casei. Furthermore, deletion of either the gene encoding the histidine kinase or the response regulator of the TC system resulted in the loss of the ability to grow on L-malic acid, thus indicating that the cognate TC system regulates and is essential for the expression of ME. Transcriptional analyses showed that expression of maeE is induced in the presence of L-malic acid and repressed by glucose, whereas TC system expression was induced by L-malic acid and was not repressed by glucose. DNase I footprinting analysis showed that MaeR binds specifically to a set of direct repeats [5'-TTATT(A/T)AA-3'] in the mae promoter region. The location of the repeats strongly suggests that MaeR activates the expression of the diverging operons maePE and maeKR where the first one is also subjected to carbon catabolite repression. PMID:19897756

  6. A comparative evaluation of different types of microbial electrolysis desalination cells for malic acid production.

    PubMed

    Liu, Guangli; Zhou, Ying; Luo, Haiping; Cheng, Xing; Zhang, Renduo; Teng, Wenkai

    2015-12-01

    The aim of this study was to investigate different microbial electrolysis desalination cells for malic acid production. The systems included microbial electrolysis desalination and chemical-production cell (MEDCC), microbial electrolysis desalination cell (MEDC) with bipolar membrane and anion exchange membrane (BP-A MEDC), MEDC with bipolar membrane and cation exchange membrane (BP-C MEDC), and modified microbial desalination cell (M-MDC). The microbial electrolysis desalination cells performed differently in terms of malic acid production and energy consumption. The MEDCC performed best with the highest malic acid production rate (18.4 ± 0.6 mmol/Lh) and the lowest energy consumption (0.35 ± 0.14 kWh/kg). The best performance of MEDCC was attributable to the neutral pH condition in the anode chamber, the lowest internal resistance, and the highest Geobacter percentage of the anode biofilm population among all the reactors.

  7. A comparative evaluation of different types of microbial electrolysis desalination cells for malic acid production.

    PubMed

    Liu, Guangli; Zhou, Ying; Luo, Haiping; Cheng, Xing; Zhang, Renduo; Teng, Wenkai

    2015-12-01

    The aim of this study was to investigate different microbial electrolysis desalination cells for malic acid production. The systems included microbial electrolysis desalination and chemical-production cell (MEDCC), microbial electrolysis desalination cell (MEDC) with bipolar membrane and anion exchange membrane (BP-A MEDC), MEDC with bipolar membrane and cation exchange membrane (BP-C MEDC), and modified microbial desalination cell (M-MDC). The microbial electrolysis desalination cells performed differently in terms of malic acid production and energy consumption. The MEDCC performed best with the highest malic acid production rate (18.4 ± 0.6 mmol/Lh) and the lowest energy consumption (0.35 ± 0.14 kWh/kg). The best performance of MEDCC was attributable to the neutral pH condition in the anode chamber, the lowest internal resistance, and the highest Geobacter percentage of the anode biofilm population among all the reactors. PMID:26367771

  8. Gamma-irradiation of malic acid in aqueous solutions. [prebiotic significance

    NASA Technical Reports Server (NTRS)

    Negron-Mendoza, A.; Graff, R. L.; Ponnamperuma, C.

    1980-01-01

    The gamma-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the nonvolatile products. Thin layer chromatography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the gamma-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  9. Acetaldehyde stimulation of net gluconeogenic carbon movement from applied malic acid in tomato fruit pericarp tissue

    SciTech Connect

    Halinska, A.; Frenkel, C. )

    1991-03-01

    Applied acetaldehyde is known to lead to sugar accumulation in fruit including tomatoes (Lycopersicon esculentum) presumably due to stimulation of gluconeogenesis. This conjecture was examined using tomato fruit pericarp discs as a test system and applied l-(U-{sup 14}C)malic acid as the source for gluconeogenic carbon mobilization. Results indicate that malic and perhaps other organic acids are carbon sources for gluconeogenesis occurring normally in ripening tomatoes. The process is stimulated by acetaldehyde apparently by attenuating the fructose-2,6-biphosphate levels. The mode of the acetaldehyde regulation of fructose-2,6-biphosphate metabolism awaits clarification.

  10. Spectra investigation on surface characteristics of graphene oxide nanosheets treated with tartaric, malic and oxalic acids.

    PubMed

    Teng, Xiyao; Yan, Manqing; Bi, Hong

    2014-01-24

    The surface characteristics of graphene oxide nanosheets (GO) treated respectively with tartaric acid, malic acid and oxalic acid, have been investigated by mainly using optical spectroscopic methods including Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible (UV-Vis) absorption and Raman spectroscopy. Additionally, the electrochemical property of the products has also been studied. The data revealed that oxygen-containing groups such as OH, COOH and CO on the GO surface have been almost removed and thus reduced graphene oxide nanosheets (RGN) were obtained. Interestingly, the number of sp(2) domains of RGN increases as treated by tartaric acid acidacid whereas the steric hindrance (SH) decreases and the ionization constant (IC) differs among these three acids. Furthermore, the specific capacitances (Cs) of GO have been greatly promoted from 2.4 F g(-1) to 100.8, 112.4, and 147 F g(-1) after treated with tartaric, malic and oxalic acids, respectively. This finding agrees well with the spectra result of the tendency of surface conjugated degree alteration. We claim that the difference in both SH and IC among these acids is the main reason for the diverse surface characteristics as well as the improved Cs of the RGN.

  11. Comparative assessment of sugar and malic acid composition in cultivated and wild apples.

    PubMed

    Ma, Baiquan; Chen, Jie; Zheng, Hongyu; Fang, Ting; Ogutu, Collins; Li, Shaohua; Han, Yuepeng; Wu, Benhong

    2015-04-01

    Soluble sugar and malic acid contents in mature fruits of 364 apple accessions were quantified using high-performance liquid chromatography (HPLC). Fructose and sucrose represented the major components of soluble sugars in cultivated fruits, whilst fructose and glucose were the major items of sugars in wild fruits. Wild fruits were significantly more acidic than cultivated fruits, whilst the average concentration of total sugars and sweetness index were quite similar between cultivated and wild fruits. Thus, our study suggests that fruit acidity rather than sweetness is likely to have undergone selection during apple domestication. Additionally, malic acid content was positively correlated with glucose content and negatively correlated with sucrose content. This suggests that selection of fruit acidity must have an effect on the proportion of sugar components in apple fruits. Our study provides information that could be helpful for future apple breeding.

  12. Dynamics of three organic acids (malic, acetic and succinic acid) in sunflower exposed to cadmium and lead.

    PubMed

    Niu, Zhixin; Li, Xiaodong; Sun, Lina; Sun, Tieheng

    2013-01-01

    Sunflower (Helianthus annuus L.) has been considered as a good candidate for bioaccumulation of heavy metals. In the present study, sunflower was used to enrich the cadmium and lead in sand culture during 90 days. Biomass, Cd and Pb uptake, three organic acids and pH in cultures were investigated. Results showed that the existence of Cd and Pb showed different interactions on the organic acids exudation. In single Cd treatments, malic and acetic acids in Cd10 showed an incremental tendency with time. In the mixed treatments of Cd and Pb, malic acids increased when 10 and 40 mg x L(-1) Cd were added into Pb50, but acetic acids in Pb50 were inhibited by Cd addition. The Cd10 supplied in Pb10 stimulated the secretion of malic and succinic acids. Moreover, the Cd or Pb uptake in sunflower showed various correlations with pH and some organic acids, which might be due to the fact that the Cd and Pb interfere with the organic acids secretion in rhizosphere of sunflower, and the changes of organic acids altered the form and bioavailability of Cd and Pb in cultures conversely.

  13. Antiplatelet activity of a novel formula composed of malic acid, succinic acid and citric acid from Cornus officinalis fruit.

    PubMed

    Zhang, Qi-Chun; Zhao, Yue; Bian, Hui-Min

    2013-12-01

    The present study investigated the antiplatelet activity of a novel formula composed by malic acid, succinic acid and citric acid with a ratio of 3:2:2. The IC50 and inhibition of platelet aggregation induced by various agonists as well as platelet adhesion were evaluated in vitro. Of note, the IC50 for the formula inhibiting adenosine diphosphate (ADP)-induced platelet aggregation was 0.185 mg/mL. Meanwhile, the formula showed more potent inhibitory effect on platelet aggregation induced by ADP and thrombin than the single component at same concentration (0.37 mg/mL). Moreover, the formula could prevent platelet adhesion significantly without influence on platelet viability.

  14. Poly(beta-L-malic acid) from agricultural substrates by Aureobasidium pullulans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report here for the first time the production of poly(beta-L-malic acid) (PMA) from agricultural substrates by the yeastlike fungus Aureobasidium pullulans. PMA is a natural biopolyester that has primarily been studied for biomedical uses as a drug carrier. However, PMA also has potential as a ...

  15. Habit modification of calcium carbonate in the presence of malic acid

    SciTech Connect

    Mao Zhaofeng; Huang Jianhua

    2007-02-15

    The ability of malic acid to control calcium carbonate morphology has been investigated by aging calcium chloride solution in the presence of urea in a 90 deg. C bath. Malic acid favors the formation of calcite. A transition from single block to aggregate with special morphology occurs upon increasing malic acid concentration. The morphological development of CaCO{sub 3} crystal obviously depends on the starting pH. CaCO{sub 3} crystal grows from spindle seed to dumbbell in the pH regime from 7 to 11; while it evolves from spindle seed, through peanut, to sphere at pH=11.5. Both dumbbell and sphere consist of rods that are elongated along c-axis and capped with three smooth, well-defined rhombic {l_brace}1 0 4{r_brace} faces. A tentative growth mechanism is proposed based on the fractal model suggested by R. Kniep and S. Busch [Angew. Chem. Int. Ed. Engl. 35 (1996) 2624]. - Graphical abstract: Dumbbell-like CaCO{sub 3} particles obtained in the presence of malic acid.

  16. Direct fungal fermentation of lignocellulosic biomass into itaconic, fumaric, and malic acids: current and future prospects.

    PubMed

    Mondala, Andro H

    2015-04-01

    Various economic and environmental sustainability concerns as well as consumer preference for bio-based products from natural sources have paved the way for the development and expansion of biorefining technologies. These involve the conversion of renewable biomass feedstock to fuels and chemicals using biological systems as alternatives to petroleum-based products. Filamentous fungi possess an expansive portfolio of products including the multifunctional organic acids itaconic, fumaric, and malic acids that have wide-ranging current applications and potentially addressable markets as platform chemicals. However, current bioprocessing technologies for the production of these compounds are mostly based on submerged fermentation, which necessitates physicochemical pretreatment and hydrolysis of lignocellulose biomass to soluble fermentable sugars in liquid media. This review will focus on current research work on fungal production of itaconic, fumaric, and malic acids and perspectives on the potential application of solid-state fungal cultivation techniques for the consolidated hydrolysis and organic acid fermentation of lignocellulosic biomass.

  17. Amperometric Low-Potential Detection of Malic Acid Using Single-Wall Carbon Nanotubes Based Electrodes

    PubMed Central

    Arvinte, Adina; Rotariu, Lucian; Bala, Camelia

    2008-01-01

    The electrocatalytical property of single-wall carbon nanotube (SWNT) modified electrode toward NADH detection was explored by cyclic voltammetry and amperometry techniques. The experimental results show that SWNT decrease the overvoltage required for oxidation of NADH (to +300 mV vs. Ag/AgCl) and this property make them suitable for dehydrogenases based biosensors. The behavior of the SWNT modified biosensor for L-malic acid was studied as an example for dehydrogenases biosensor. The amperometric measurements indicate that malate dehydrogenase (MDH) can be strongly adsorbed on the surface of the SWNT-modified electrode to form an approximate monolayer film. Enzyme immobilization in Nafion membrane can increase the biosensor stability. A linear calibration curve was obtained for L-malic acid concentrations between 0.2 and 1mM.

  18. Anti-thrombotic effect of a novel formula from Corni fructus with malic acid, succinic acid and citric acid.

    PubMed

    Zhang, Qi-Chun; Zhao, Yue; Bian, Hui-Min

    2014-05-01

    Our previous investigation had confirmed the inhibition of platelet aggregation of a novel Corni fructus-derived formula composed of malic acid, succinic acid and citric acid with a ratio of 3:2:2. The present study was to further evaluate the anti-thrombotic effect of the formula in vivo. Mice of acute pulmonary thromboembolism, and rats of arterial thrombosis were used to determine the anti-thrombotic effect of the formula. Histology analysis of endothelium was conducted with hematoxylin and eosin stain. TXB2 , 6-K-PGF1α , cAMP, cGMP and NO in rat plasma were determined. In vitro assay of αIIbβ3 and phosphorylation of ERK1/2 were performed in ADP-treated platelet. The formula significantly reduced the recovery time and mortality rate of mice with acute pulmonary thromboembolism. Remarkably extended occlusion time, decreased thrombus weight and more integrated endothelium were observed in rat with the formula. Enhanced 6-K-PGF1α , cGMP and NO, but not TXB2 and cAMP, were demonstrated in rat plasma with treatment of the formula. Finally, the formula was shown to inhibit αIIbβ3 expression and activation of ERK1/2 in platelet. The formula shows positive anti-thrombotic effect. The direct interference on ADP activated signaling in platelet and regulation of endothelium function are two primary pathways involved in the action on thrombosis.

  19. Effect of Pre-Harvest Foliar Application of Citric Acid and Malic Acid on Chlorophyll Content and Post-Harvest Vase Life of Lilium cv. Brunello.

    PubMed

    Darandeh, Nafiseh; Hadavi, Ebrahim

    2011-01-01

    Citric acid is a regular ingredient in many vase solution formulations but pre-harvest use of citric acid is a novel method in vase life extension of cut flowers, which is reported on tuberose earlier. In order to verify previous result, and check for possible substitution of citric acid by malic acid, the current research was designed. Citric acid (0, 0.075, 0.15% w/v) and malic acid (0, 0.075, 0.15% w/v) were used in a factorial design with three replications. Foliar sprays were applied two times during growth period of Lilium plants. The results point out that 0.15% citric acid alone had increased vase life from 11.8 in control treatment to 14 days (α < 0.05). The interesting finding was the effect of citric acid on bulbil weight, which was decreased from 9 g in control to 1.5 g in treatment containing combination of 0.075% citric acid and 0.075% malic acid. Malic acid while having no direct effect on pre-mentioned traits surprisingly increased the chlorophyll content significantly. The interaction effect between citric acid and malic acid on vase life and chlorophyll content proved significant and was evident in results, both as antagonistic and synergistic in various traits.

  20. Role of malic enzyme during fatty acid synthesis in the oleaginous fungus Mortierella alpina.

    PubMed

    Hao, Guangfei; Chen, Haiqin; Wang, Lei; Gu, Zhennan; Song, Yuanda; Zhang, Hao; Chen, Wei; Chen, Yong Q

    2014-05-01

    The generation of NADPH by malic enzyme (ME) was postulated to be a rate-limiting step during fatty acid synthesis in oleaginous fungi, based primarily on the results from research focusing on ME in Mucor circinelloides. This hypothesis is challenged by a recent study showing that leucine metabolism, rather than ME, is critical for fatty acid synthesis in M. circinelloides. To clarify this, the gene encoding ME isoform E from Mortierella alpina was homologously expressed. ME overexpression increased the fatty acid content by 30% compared to that for a control. Our results suggest that ME may not be the sole rate-limiting enzyme, but does play a role, during fatty acid synthesis in oleaginous fungi.

  1. Development of poly(aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition.

    PubMed

    Mithil Kumar, N; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, K; Bux, F

    2015-01-01

    Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition efficiency, PSI was modified by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal properties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and gel permeation chromatography. The effectiveness of six different molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65-70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inorganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10 mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly effective scale inhibitor for cooling water treatment applications.

  2. Metabolic engineering of Aspergillus oryzae NRRL 3488 for increased production of L-malic acid.

    PubMed

    Brown, Stephen H; Bashkirova, Lena; Berka, Randy; Chandler, Tyler; Doty, Tammy; McCall, Keith; McCulloch, Michael; McFarland, Sarah; Thompson, Sheryl; Yaver, Debbie; Berry, Alan

    2013-10-01

    Malic acid, a petroleum-derived C4-dicarboxylic acid that is used in the food and beverage industries, is also produced by a number of microorganisms that follow a variety of metabolic routes. Several members of the genus Aspergillus utilize a two-step cytosolic pathway from pyruvate to malate known as the reductive tricarboxylic acid (rTCA) pathway. This simple and efficient pathway has a maximum theoretical yield of 2 mol malate/mol glucose when the starting pyruvate originates from glycolysis. Production of malic acid by Aspergillus oryzae NRRL 3488 was first improved by overexpression of a native C4-dicarboxylate transporter, leading to a greater than twofold increase in the rate of malate production. Overexpression of the native cytosolic alleles of pyruvate carboxylase and malate dehydrogenase, comprising the rTCA pathway, in conjunction with the transporter resulted in an additional 27 % increase in malate production rate. A strain overexpressing all three genes achieved a malate titer of 154 g/L in 164 h, corresponding to a production rate of 0.94 g/L/h, with an associated yield on glucose of 1.38 mol/mol (69 % of the theoretical maximum). This rate of malate production is the highest reported for any microbial system.

  3. Inhibition of Listeria monocytogenes and Salmonella by combinations of oriental mustard, malic acid, and EDTA.

    PubMed

    Olaimat, Amin N; Holley, Richard A

    2014-04-01

    The antimicrobial activities of oriental mustard extract alone or combined with malic acid and EDTA were investigated against Salmonella spp. or Listeria monocytogenes at different temperatures. Five strain Salmonella or L. monocytogenes cocktails were separately inoculated in Brain Heart Infusion broth containing 0.5% (w/v) aqueous oriental mustard extract and incubated at 4 °C to 21 °C for 21 d. For inhibitor combination tests, Salmonella Typhimurium 02:8423 and L. monocytogenes 2-243 were individually inoculated in Mueller Hinton broth containing the mustard extract with either or both 0.2% (w/v) malic acid and 0.2% (w/v) EDTA and incubated at 10 °C or 21 °C for 10 to 14 d. Mustard extract inhibited growth of the L. monocytogenes cocktail at 4 °C up to 21 d (2.3 log10 CFU/mL inhibition) or at 10 °C for 7 d (2.4 log10 CFU/mL inhibition). Salmonella spp. viability was slightly, but significantly reduced by mustard extract at 4 °C by 21 d. Although hydrolysis of sinigrin in mustard extract by both pathogens was 2 to 6 times higher at 21 °C than at 4 °C to 10 °C, mustard was not inhibitory at 21 °C, perhaps because of the instability of its hydrolysis product (allyl isothiocyanate). At 21 °C, additive inhibitory effects of mustard extract with EDTA or malic acid led to undetectable levels of S. Typhimurium and L. monocytogenes by 7 d and 10 d, respectively. At 10 °C, S. Typhimurium was similarly susceptible, but combinations of antimicrobials were not more inhibitory to L. monocytogenes than the individual agents.

  4. Anti-crease finishing of cotton fabrics based on crosslinking of cellulose with acryloyl malic acid.

    PubMed

    Qi, Huan; Huang, Yangen; Ji, Bolin; Sun, Gang; Qing, Feng-Ling; Hu, Chunyan; Yan, Kelu

    2016-01-01

    Maleic acid (MA) has been explored to replace formaldehyde-based dimethylol dihydroxy ethylene urea (DMDHEU) for cotton anti-crease finishing. However, the resilience of treated fabrics was not satisfactorily improved. In this study, acryloyl malic acid (AMA) was synthesized and applied on fabrics as a novel crosslinking agent. The results showed that both crease recovery angle and whiteness index of treated samples were higher than those of MA in the presence/absence of catalyst sodium hypophosphite (SHP). Chemical structure of AMA was confirmed by NMR and MS spectra. The possible crosslinking mechanism between AMA and cellulose was investigated by means of (13)C NMR, MS, FTIR and phosphorus content analyses. It was found that AMA could form ester bonds with cellulose by formation of anhydride intermediate. Meanwhile, additional reaction of double bonds on AMA with another molecule or PH of SHP residual has also contributed to the crosslinking. A reaction equation was proposed based on the analyses. PMID:26453855

  5. Isolation of a high malic and low acetic acid-producing sake yeast Saccharomyces cerevisiae strain screened from respiratory inhibitor 2,4-dinitrophenol (DNP)-resistant strains.

    PubMed

    Kosugi, Shingo; Kiyoshi, Keiji; Oba, Takahiro; Kusumoto, Kenichi; Kadokura, Toshimori; Nakazato, Atsumi; Nakayama, Shunichi

    2014-01-01

    We isolated 2,4-dinitrophenol (DNP)-resistant sake yeast strains by UV mutagenesis. Among the DNP-resistant mutants, we focused on strains exhibiting high malic acid and low acetic acid production. The improved organic acid composition is unlikely to be under the control of enzyme activities related to malic and acetic acid synthesis pathways. Instead, low mitochondrial activity was observed in DNP-resistant mutants, indicating that the excess pyruvic acid generated during glycolysis is not metabolized in the mitochondria but converted to malic acid in the cytosol. In addition, the NADH/NAD(+) ratio of the DNP-resistant strains was higher than that of the parental strain K901. These results suggest that the increased NADH/NAD(+) ratio together with the low mitochondrial activity alter the organic acid composition because malic acid synthesis requires NADH, while acetic acid uses NAD(+).

  6. Chiral ligand-exchange separation and determination of malic acid enantiomers in apple juice by open-tubular capillary electrochromatography.

    PubMed

    Aydoğan, Cemil; Karakoç, Veyis; Denizli, Adil

    2015-11-15

    This study describes the application of an open tubular capillary column for chiral ligand-exchange separation and determination of malic acid enantiomers in apple juice by open-tubular capillary electrochromatography (OT-CEC). The open tubular column was prepared by in-situ grafting polymerization of 3-chloro-2-hydroxypropyl methacrylate (HPMA-Cl) and followed by L-Histidine (L-His) modification. L-His was used as a chiral ligand-exchange selector and copper (II) as a central ion. The electrochromatographic characterization of the open tubular column was performed with the use of thiourea as an electroosmotic flow (EOF) marker. Factors affecting electrochromatographic enantioseparation of malic acid were also studied. The running buffer conditions for optimum enantioseparation of malic acid were found to be ACN/5.0mM CuSO4, 20.0mM (NH4)2SO4 (60/40%, v/v) adjusted to pH 3.0. The separation and determination of the enantiomers of malic acid in the apple juice solution diluted 10- to 40-folds were successfully achieved.

  7. Production of succinic acid through overexpression of NAD(+)-dependent malic enzyme in an Escherichia coli mutant.

    PubMed Central

    Stols, L; Donnelly, M I

    1997-01-01

    NAD(+)-dependent malic enzyme was cloned from the Escherichia coli genome by PCR based on the published partial sequence of the gene. The enzyme was overexpressed and purified to near homogeneity in two chromatographic steps and was analyzed kinetically in the forward and reverse directions. The Km values determined in the presence of saturating cofactor and manganese ion were 0.26 mM for malate (physiological direction) and 16 mM for pyruvate (reverse direction). When malic enzyme was induced under appropriate culture conditions in a strain of E. coli that was unable to ferment glucose and accumulated pyruvate, fermentative metabolism of glucose was restored. Succinic acid was the major fermentation product formed. When this fermentation was performed in the presence of hydrogen, the yield of succinic acid increased. The constructed pathway represents an alternative metabolic route for the fermentative production of dicarboxylic acids from renewable feedstocks. PMID:9212416

  8. Adaptation and Transcriptome Analysis of Aureobasidium pullulans in Corncob Hydrolysate for Increased Inhibitor Tolerance to Malic Acid Production

    PubMed Central

    Zou, Xiang; Wang, Yongkang; Tu, Guangwei; Zan, Zhanquan; Wu, Xiaoyan

    2015-01-01

    Malic acid is a dicarboxylic acid widely used in the food industry, and is also a potential C4 platform chemical. Corncob is a low-cost renewable feedstock from agricultural industry. However, side-reaction products (furfural, 5-hydroxymethylfurfural (HMF), formic acid, and acetic acid) that severely hinder fermentation are formed during corncob pretreatment. The process for producing malic acid from a hydrolysate of corncob was investigated with a polymalic acid (PMA)-producing Aureobasidium pullulans strain. Under the optimal hydrolysate sugar concentration 110 g/L, A. pullulans was further adapted in an aerobic fibrous bed bioreactor (AFBB) by gradually increasing the sugar concentration of hydrolysate. After nine batches of fermentation, the production and productivity of malic acid reached 38.6 g/L and 0.4 g/L h, respectively, which was higher than that in the first batch (27.6 g/L and 0.29 g/L h, respectively). The adapted strain could grow under the stress of 0.5 g/L furfural, 3 g/L HMF, 2g/L acetic acid, and 0.5 g/L formic acid, whereas the wild type did not. Transcriptome analysis revealed that the differentially expressed genes were related to carbohydrate transport and metabolism, lipid transport and metabolism, signal transduction mechanism, redox metabolism, and energy production and conversion under 0.5 g/L furfural and 3 g/L HMF stress conditions. In total, 42 genes in the adapted strain were upregulated by 15-fold or more, and qRT-PCR also confirmed that the expression levels of key genes (i.e. SIR, GSS, CYS, and GSR) involved in sulfur assimilation pathway were upregulated by over 10-fold in adapted strain for cellular protection against oxidative stress. PMID:25793624

  9. Automatic bionalyzer using an integrated amperometric biosensor for the determination of L-malic acid in wines.

    PubMed

    Vargas, E; Ruiz, M A; Ferrero, F J; Campuzano, S; Ruiz-Valdepeñas Montiel, V; Reviejo, A J; Pingarrón, J M

    2016-09-01

    A new automatic bioanalyzer for L-malic acid using an integrated amperometric biosensor as detector is reported for the first time in this work. The biosensor is constructed by gold film sputtering deposition on a stainless steel disk electrode and co-immobilization of the enzymes malate dehydrogenase (MDH) and diaphorase (DP) together with the redox mediator tetrathiafulvalene (TTF) by means of dialysis membrane. The analytical performance of the biosensor was evaluated when it was used as amperometric detector in three different analytical methodologies: stirred solutions, semiautomatic FIA system and automatic bioanalyzer. The bienzyme biosensor exhibited great analytical performance in terms of sensitivity, selectivity and reproducibility of the measurements and its usefulness was demonstrated by analyzing wine reference materials with certified content of L-malic acid. The attractive analytical and operational characteristics demonstrated by the automatic bioanalyzer make it a promising simple, rapid and field-based tool for routine wine and fruit control.

  10. Automatic bionalyzer using an integrated amperometric biosensor for the determination of L-malic acid in wines.

    PubMed

    Vargas, E; Ruiz, M A; Ferrero, F J; Campuzano, S; Ruiz-Valdepeñas Montiel, V; Reviejo, A J; Pingarrón, J M

    2016-09-01

    A new automatic bioanalyzer for L-malic acid using an integrated amperometric biosensor as detector is reported for the first time in this work. The biosensor is constructed by gold film sputtering deposition on a stainless steel disk electrode and co-immobilization of the enzymes malate dehydrogenase (MDH) and diaphorase (DP) together with the redox mediator tetrathiafulvalene (TTF) by means of dialysis membrane. The analytical performance of the biosensor was evaluated when it was used as amperometric detector in three different analytical methodologies: stirred solutions, semiautomatic FIA system and automatic bioanalyzer. The bienzyme biosensor exhibited great analytical performance in terms of sensitivity, selectivity and reproducibility of the measurements and its usefulness was demonstrated by analyzing wine reference materials with certified content of L-malic acid. The attractive analytical and operational characteristics demonstrated by the automatic bioanalyzer make it a promising simple, rapid and field-based tool for routine wine and fruit control. PMID:27343571

  11. Malic Acid Production by Saccharomyces cerevisiae: Engineering of Pyruvate Carboxylation, Oxaloacetate Reduction, and Malate Export▿ †

    PubMed Central

    Zelle, Rintze M.; de Hulster, Erik; van Winden, Wouter A.; de Waard, Pieter; Dijkema, Cor; Winkler, Aaron A.; Geertman, Jan-Maarten A.; van Dijken, Johannes P.; Pronk, Jack T.; van Maris, Antonius J. A.

    2008-01-01

    Malic acid is a potential biomass-derivable “building block” for chemical synthesis. Since wild-type Saccharomyces cerevisiae strains produce only low levels of malate, metabolic engineering is required to achieve efficient malate production with this yeast. A promising pathway for malate production from glucose proceeds via carboxylation of pyruvate, followed by reduction of oxaloacetate to malate. This redox- and ATP-neutral, CO2-fixing pathway has a theoretical maximum yield of 2 mol malate (mol glucose)−1. A previously engineered glucose-tolerant, C2-independent pyruvate decarboxylase-negative S. cerevisiae strain was used as the platform to evaluate the impact of individual and combined introduction of three genetic modifications: (i) overexpression of the native pyruvate carboxylase encoded by PYC2, (ii) high-level expression of an allele of the MDH3 gene, of which the encoded malate dehydrogenase was retargeted to the cytosol by deletion of the C-terminal peroxisomal targeting sequence, and (iii) functional expression of the Schizosaccharomyces pombe malate transporter gene SpMAE1. While single or double modifications improved malate production, the highest malate yields and titers were obtained with the simultaneous introduction of all three modifications. In glucose-grown batch cultures, the resulting engineered strain produced malate at titers of up to 59 g liter−1 at a malate yield of 0.42 mol (mol glucose)−1. Metabolic flux analysis showed that metabolite labeling patterns observed upon nuclear magnetic resonance analyses of cultures grown on 13C-labeled glucose were consistent with the envisaged nonoxidative, fermentative pathway for malate production. The engineered strains still produced substantial amounts of pyruvate, indicating that the pathway efficiency can be further improved. PMID:18344340

  12. Poly(trimethylene carbonate)/Poly(malic acid) Amphiphilic Diblock Copolymers as Biocompatible Nanoparticles.

    PubMed

    Barouti, Ghislaine; Khalil, Ali; Orione, Clement; Jarnouen, Kathleen; Cammas-Marion, Sandrine; Loyer, Pascal; Guillaume, Sophie M

    2016-02-18

    Amphiphilic polycarbonate-poly(hydroxyalkanoate) diblock copolymers, namely, poly(trimethylene carbonate) (PTMC)-b-poly(β-malic acid) (PMLA), are reported for the first time. The synthetic strategy relies on commercially available catalysts and initiator. The controlled ring-opening polymerization (ROP) of trimethylene carbonate (TMC) catalyzed by the organic guanidine base 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), associated with iPrOH as an initiator, provided iPrO-PTMC-OH, which served as a macroinitiator in the controlled ROP of benzyl β-malolactonate (MLABe) catalyzed by the neodymium triflate salt (Nd(OTf)3). The resulting hydrophobic iPrO-PTMC-b-PMLABe-OH copolymers were then hydrogenolyzed into the parent iPrO-PTMC-b-PMLA-OH copolymers. A range of well-defined copolymers, featuring different sizes of segments (Mn,NMR up to 9300 g mol(-1) ; ÐM =1.28-1.40), were thus isolated in gram quantities, as evidenced by NMR spectroscopy, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, and contact angle analyses. Subsequently, PTMC-b-PMLA copolymers with different hydrophilic weight fractions (11-75 %) self-assembled in phosphate-buffered saline upon nanoprecipitation into well-defined nano-objects with Dh =61-176 nm, a polydispersity index <0.25, and a negative surface charge, as characterized by dynamic light scattering and zeta-potential analyses. In addition, these nanoparticles demonstrated no significant effect on cell viability at low concentrations, and a very low cytotoxicity at high concentrations only for PTMC-b-PMLA copolymers exhibiting hydrophilic fractions over 47 %, thus illustrating the potential of these copolymers as promising nanoparticles.

  13. Malic acid production by Saccharomyces cerevisiae: engineering of pyruvate carboxylation, oxaloacetate reduction, and malate export.

    PubMed

    Zelle, Rintze M; de Hulster, Erik; van Winden, Wouter A; de Waard, Pieter; Dijkema, Cor; Winkler, Aaron A; Geertman, Jan-Maarten A; van Dijken, Johannes P; Pronk, Jack T; van Maris, Antonius J A

    2008-05-01

    Malic acid is a potential biomass-derivable "building block" for chemical synthesis. Since wild-type Saccharomyces cerevisiae strains produce only low levels of malate, metabolic engineering is required to achieve efficient malate production with this yeast. A promising pathway for malate production from glucose proceeds via carboxylation of pyruvate, followed by reduction of oxaloacetate to malate. This redox- and ATP-neutral, CO(2)-fixing pathway has a theoretical maximum yield of 2 mol malate (mol glucose)(-1). A previously engineered glucose-tolerant, C(2)-independent pyruvate decarboxylase-negative S. cerevisiae strain was used as the platform to evaluate the impact of individual and combined introduction of three genetic modifications: (i) overexpression of the native pyruvate carboxylase encoded by PYC2, (ii) high-level expression of an allele of the MDH3 gene, of which the encoded malate dehydrogenase was retargeted to the cytosol by deletion of the C-terminal peroxisomal targeting sequence, and (iii) functional expression of the Schizosaccharomyces pombe malate transporter gene SpMAE1. While single or double modifications improved malate production, the highest malate yields and titers were obtained with the simultaneous introduction of all three modifications. In glucose-grown batch cultures, the resulting engineered strain produced malate at titers of up to 59 g liter(-1) at a malate yield of 0.42 mol (mol glucose)(-1). Metabolic flux analysis showed that metabolite labeling patterns observed upon nuclear magnetic resonance analyses of cultures grown on (13)C-labeled glucose were consistent with the envisaged nonoxidative, fermentative pathway for malate production. The engineered strains still produced substantial amounts of pyruvate, indicating that the pathway efficiency can be further improved.

  14. Preparation of Two Types of Polymeric Micelles Based on Poly(β-L-Malic Acid) for Antitumor Drug Delivery.

    PubMed

    Yang, Tiehong; Li, Wei; Duan, Xiao; Zhu, Lin; Fan, Li; Qiao, Youbei; Wu, Hong

    2016-01-01

    Polymeric micelles represent an effective delivery system for poorly water-soluble anticancer drugs. In this work, two types of CPT-conjugated polymers were synthesized based on poly(β-L-malic acid) (PMLA) derivatives. Folic acid (FA) was introduced into the polymers as tumor targeting group. The micellization behaviors of these polymers and antitumor activity of different self-assembled micelles were investigated. Results indicate that poly(ethylene glycol)-poly(β-L-malic acid)-campotothecin-I (PEG-PMLA-CPT-I, P1) is a grafted copolymer, and could form star micelles in aqueous solution with a diameter of about 97 nm, also that PEG-PMLA-CPT-II (P2) is an amphiphilic block copolymer, and could form crew cut micelles with a diameter of about 76 nm. Both P1 and P2 micelles could improve the cellular uptake of CPT, especially the FA-modified micelles, while P2 micelles showed higher stability, higher drug loading efficiency, smaller size, and slower drug release rate than that of P1 micelles. These results suggested that the P2 (crew cut) micelles possess better stability than that of the P1 (star) micelles and might be a potential drug delivery system for cancer therapy.

  15. Preparation of Two Types of Polymeric Micelles Based on Poly(β-L-Malic Acid) for Antitumor Drug Delivery.

    PubMed

    Yang, Tiehong; Li, Wei; Duan, Xiao; Zhu, Lin; Fan, Li; Qiao, Youbei; Wu, Hong

    2016-01-01

    Polymeric micelles represent an effective delivery system for poorly water-soluble anticancer drugs. In this work, two types of CPT-conjugated polymers were synthesized based on poly(β-L-malic acid) (PMLA) derivatives. Folic acid (FA) was introduced into the polymers as tumor targeting group. The micellization behaviors of these polymers and antitumor activity of different self-assembled micelles were investigated. Results indicate that poly(ethylene glycol)-poly(β-L-malic acid)-campotothecin-I (PEG-PMLA-CPT-I, P1) is a grafted copolymer, and could form star micelles in aqueous solution with a diameter of about 97 nm, also that PEG-PMLA-CPT-II (P2) is an amphiphilic block copolymer, and could form crew cut micelles with a diameter of about 76 nm. Both P1 and P2 micelles could improve the cellular uptake of CPT, especially the FA-modified micelles, while P2 micelles showed higher stability, higher drug loading efficiency, smaller size, and slower drug release rate than that of P1 micelles. These results suggested that the P2 (crew cut) micelles possess better stability than that of the P1 (star) micelles and might be a potential drug delivery system for cancer therapy. PMID:27649562

  16. Preparation of Two Types of Polymeric Micelles Based on Poly(β-L-Malic Acid) for Antitumor Drug Delivery

    PubMed Central

    Duan, Xiao; Zhu, Lin; Fan, Li; Qiao, Youbei; Wu, Hong

    2016-01-01

    Polymeric micelles represent an effective delivery system for poorly water-soluble anticancer drugs. In this work, two types of CPT-conjugated polymers were synthesized based on poly(β-L-malic acid) (PMLA) derivatives. Folic acid (FA) was introduced into the polymers as tumor targeting group. The micellization behaviors of these polymers and antitumor activity of different self-assembled micelles were investigated. Results indicate that poly(ethylene glycol)-poly(β-L-malic acid)-campotothecin-I (PEG-PMLA-CPT-I, P1) is a grafted copolymer, and could form star micelles in aqueous solution with a diameter of about 97 nm, also that PEG-PMLA-CPT-II (P2) is an amphiphilic block copolymer, and could form crew cut micelles with a diameter of about 76 nm. Both P1 and P2 micelles could improve the cellular uptake of CPT, especially the FA-modified micelles, while P2 micelles showed higher stability, higher drug loading efficiency, smaller size, and slower drug release rate than that of P1 micelles. These results suggested that the P2 (crew cut) micelles possess better stability than that of the P1 (star) micelles and might be a potential drug delivery system for cancer therapy. PMID:27649562

  17. Effects of different dwarfing interstocks on key enzyme activities and the expression of genes related to malic acid metabolism in Red Fuji apples.

    PubMed

    Shi, J; Li, F F; Ma, H; Li, Z Y; Xu, J Z

    2015-12-22

    In this experiment, the test materials were 'Red Fuji' apple trees grafted onto three interstocks (No. 53, No. 111, and No. 236), which were chosen from SH40 seeding interstocks. The content of malic acid, the enzyme activities, and the expression of genes related to malic acid metabolism were determined during fruit development.The results showed that malic acid content in the ripe fruit on interstock No. 53 was higher than that in the interstock No. 111 fruit. The malate dehydrogenase (NAD-MDH) activity in apples on interstock No. 53 was highest on Day 30, Day 100, and Day 160 after bloom, and the malic enzyme (NADP-ME) activity in apples on interstock No. 111 was higher than in the interstock No. 53 fruit from Day 70 to Day 100 after bloom. The relative expression of NAD-MDH genes in interstock No. 53 fruit was higher than in No. 236 fruit on Day 100 after bloom, but the relative expression of NADP-ME in No. 236 interstock fruit was lower than in No. 53 fruit. The relative expression of NAD-MDH genes in No. 53 interstock fruit was highest on Day 160 after bloom. This might have been the main reason for the difference in the accumulation of malic acid in the ripe apples.There was a positive correlation between the relative expression of phosphoenolpyruvate carboxylase (PEPC) and the malic acid content of the fruit, and the content of malic acid in the apples was affected by the PEPC activity during the early developmental stage.

  18. Effects of different dwarfing interstocks on key enzyme activities and the expression of genes related to malic acid metabolism in Red Fuji apples.

    PubMed

    Shi, J; Li, F F; Ma, H; Li, Z Y; Xu, J Z

    2015-01-01

    In this experiment, the test materials were 'Red Fuji' apple trees grafted onto three interstocks (No. 53, No. 111, and No. 236), which were chosen from SH40 seeding interstocks. The content of malic acid, the enzyme activities, and the expression of genes related to malic acid metabolism were determined during fruit development.The results showed that malic acid content in the ripe fruit on interstock No. 53 was higher than that in the interstock No. 111 fruit. The malate dehydrogenase (NAD-MDH) activity in apples on interstock No. 53 was highest on Day 30, Day 100, and Day 160 after bloom, and the malic enzyme (NADP-ME) activity in apples on interstock No. 111 was higher than in the interstock No. 53 fruit from Day 70 to Day 100 after bloom. The relative expression of NAD-MDH genes in interstock No. 53 fruit was higher than in No. 236 fruit on Day 100 after bloom, but the relative expression of NADP-ME in No. 236 interstock fruit was lower than in No. 53 fruit. The relative expression of NAD-MDH genes in No. 53 interstock fruit was highest on Day 160 after bloom. This might have been the main reason for the difference in the accumulation of malic acid in the ripe apples.There was a positive correlation between the relative expression of phosphoenolpyruvate carboxylase (PEPC) and the malic acid content of the fruit, and the content of malic acid in the apples was affected by the PEPC activity during the early developmental stage. PMID:26782412

  19. Enhancement of critical current of SiC and malic acid codoped MgB2/Fe wires

    NASA Astrophysics Data System (ADS)

    Li, W. X.; Chen, R. H.; Xu, X.; Hu, Y. M.; Zhu, M. Y.; Li, Y.; Dou, S. X.

    2015-09-01

    The influences of microstructure, connectivity, and disorder on the critical current density, Jc, are discussed to clarify the different mechanisms of Jc(H) in different magnetic field ranges for in situ and combined in situ/ex situ MgB2/Fe wires with nano SiC and malic acid codoping. Sintering temperature plays a very important role in the electromagnetic properties at different temperatures and under various magnetic fields. Connectivity, upper critical field, Hc2, and irreversibility field, Hirr, are studied to demonstrate the mechanism of Jc dependence on magnetic field. The combined in situ/ex situ process is proved to be a promising technique for fabrication of practical MgB2 wires.

  20. [Studies on the correlation between production of L-malic acid and some cytosolic enzymes in the L-malic acid producing strain Aspergillus sp. N1-14].

    PubMed

    Zhou, X; Wu, Q; Cai, Z; Zhang, J

    2000-10-01

    The cytosol enzymatic study in the case of high L-malic acid(LMA) production of Aspergillus sp. N1-14' was reported. The activities of 4 kind enzymes that catalyse the CO2 fixation reactions have been detected, which are pyruvate carboxylase(PC), phosphoenolpyruvate carboxlase (PEPC), phosphoenolpyurvate carboxykinase(PCK) and malic enzyme(ME). With the exception of ME, the linear correlation was found between activities of three carboxlases and the production rate of LMA. The activity of malate dehydrogenase(MDH) was at the level of 2-3 exponential higher than that of the other analysed enzymes, while the activity of succinate dehydrogenase(SDH) was much lower, and as a discrepancy, SDH was in a positive correlation to the content of LMA in fermenting slurry(r = 0.9252). It is shown that the accumulated LMA acted as an activator of SDH. Through dynamic study, it is found that, in contrast with the slow and even increase of biomass, the content of cytosol protein(Cp) sharply fluctuated mainly due to the changes of aeration conditions. The data of the linear correlation coefficients(r) of activities of cytosol enzymes to Cp(PC r = 0.9563, PEPC r = 0.7688, PCK r = 0.7300, MDH r = 0.3920, SDH r = -0.2086) exhibited an inner law of protein synthesis. Experiment of increasing the amount of spore inoculum resulted in increase of LMA and decrease of SA. After fermenting 120 h in a 5 L stirred fermentor, with 3-fold of original spore inoculum 105.88 g/L of LMA was achieved, the overall productivity was 0.883 g/(L.h), the converting rate of glucose to LMA was 78.43%. This result supports the exist of a inner law of protein synthesis in the early period of LMA fermentation by Aspergillus sp. N1-14'.

  1. The Unusual Acid-Accumulating Behavior during Ripening of Cherimoya (Annona cherimola Mill.) is Linked to Changes in Transcription and Enzyme Activity Related to Citric and Malic Acid Metabolism.

    PubMed

    González-Agüero, Mauricio; Tejerina Pardo, Luis; Zamudio, María Sofía; Contreras, Carolina; Undurraga, Pedro; Defilippi, Bruno G

    2016-04-25

    Cherimoya (Annona cherimola Mill.) is a subtropical fruit characterized by a significant increase in organic acid levels during ripening, making it an interesting model for studying the relationship between acidity and fruit flavor. In this work, we focused on understanding the balance between the concentration of organic acids and the gene expression and activity of enzymes involved in the synthesis and degradation of these metabolites during the development and ripening of cherimoya cv. "Concha Lisa". Our results showed an early accumulation of citric acid and other changes associated with the accumulation of transcripts encoding citrate catabolism enzymes. During ripening, a 2-fold increase in malic acid and a 6-fold increase in citric acid were detected. By comparing the contents of these compounds with gene expression and enzymatic activity levels, we determined that cytoplasmic NAD-dependent malate dehydrogenase (cyNAD-MDH) and mitochondrial citrate synthase (mCS) play important regulatory roles in the malic and citric acid biosynthetic pathways.

  2. Improved detection of sugar addition to maple syrup using malic acid as internal standard and in 13C isotope ratio mass spectrometry (IRMS).

    PubMed

    Tremblay, Patrice; Paquin, Réal

    2007-01-24

    Stable carbon isotope ratio mass spectrometry (delta13C IRMS) was used to detect maple syrup adulteration by exogenous sugar addition (beet and cane sugar). Malic acid present in maple syrup is proposed as an isotopic internal standard to improve actual adulteration detection levels. A lead precipitation method has been modified to isolate quantitatively malic acid from maple syrup using preparative reversed-phase liquid chromatography. The stable carbon isotopic ratio of malic acid isolated from this procedure shows an excellent accuracy and repeatability of 0.01 and 0.1 per thousand respectively, confirming that the modified lead precipitation method is an isotopic fractionation-free process. A new approach is proposed to detect adulteration based on the correlation existing between the delta13Cmalic acid and the delta13Csugars-delta13Cmalic acid (r = 0.704). This technique has been tested on a set of 56 authentic maple syrup samples. Additionally, authentic samples were spiked with exogeneous sugars. The mean theoretical detection level was statistically lowered using this technique in comparison with the usual two-standard deviation approach, especially when maple syrup is adulterated with beet sugar : 24 +/- 12% of adulteration detection versus 48 +/- 20% (t-test, p = 7.3 x 10-15). The method was also applied to published data for pineapple juices and honey with the same improvement. PMID:17227042

  3. A catalytic triad is responsible for acid-base chemistry in the Ascaris suum NAD-malic enzyme.

    PubMed

    Karsten, William E; Liu, Dali; Rao, G S Jagannatha; Harris, Ben G; Cook, Paul F

    2005-03-01

    The pH dependence of kinetic parameters of several active site mutants of the Ascaris suum NAD-malic enzyme was investigated to determine the role of amino acid residues likely involved in catalysis on the basis of three-dimensional structures of malic enzyme. Lysine 199 is positioned to act as the general base that accepts a proton from the 2-hydroxyl of malate during the hydride transfer step. The pH dependence of V/K(malate) for the K199R mutant enzyme reveals a pK of 5.3 for an enzymatic group required to be unprotonated for activity and a second pK of 6.3 that leads to a 10-fold loss in activity above the pK of 6.3 to a new constant value up to pH 10. The V profile for K199R is pH independent from pH 5.5 to pH 10 and decreases below a pK of 4.9. Tyrosine 126 is positioned to act as the general acid that donates a proton to the enolpyruvate intermediate to form pyruvate. The pH dependence of V/K(malate) for the Y126F mutant is qualitatively similar to K199R, with a requirement for a group to be unprotonated for activity with a pK of 5.6 and a partial activity loss of about 3-fold above a pK of 6.7 to a new constant value. The Y126F mutant enzyme is about 60000-fold less active than the wild-type enzyme. In contrast to K199R, the V rate profile for Y126F also shows a partial activity loss above pH 6.6. The wild-type pH profiles were reinvestigated in light of the discovery of the partial activity change for the mutant enzymes. The wild-type V/K(malate) pH-rate profile exhibits the requirement for a group to be unprotonated for catalysis with a pK of 5.6 and also shows the partial activity loss above a pK of 6.4. The wild-type V pH-rate profile decreases below a pK of 5.2 and is pH independent from pH 5.5 to pH 10. Aspartate 294 is within hydrogen-bonding distance to K199 in the open and closed forms of malic enzyme. D294A is about 13000-fold less active than the wild-type enzyme, and the pH-rate profile for V/K(malate) indicates the mutant is only active above p

  4. Exogenous malic and acetic acids reduce cadmium phytotoxicity and enhance cadmium accumulation in roots of sunflower plants.

    PubMed

    Hawrylak-Nowak, Barbara; Dresler, Sławomir; Matraszek, Renata

    2015-09-01

    There is increasing evidence showing that low molecular weight organic acids (LMWOA) are involved in heavy metal resistance mechanisms in plants. The aim of this study was to investigate the effects of exogenous malic (MA) or acetic (AA) acids on the toxicity and accumulation of cadmium (Cd) in sunflower (Helianthus annuus L.). For this purpose, plants were grown in hydroponics under controlled conditions. Single Cd stress (5 μM Cd for 14 days) induced strong phytotoxic effects, as indicated by a decrease in all growth parameters, concentration of photosynthetic pigments, and root activity, as well as a high level of hydrogen peroxide (H2O2) accumulation. Exogenous MA or AA (250 or 500 μM) applied to the Cd-containing medium enhanced the accumulation of Cd by the roots and limited Cd translocation to the shoots. Moreover, the MA or AA applied more or less reduced Cd phytotoxicity by increasing the growth parameters, photosynthetic pigment concentrations, decreasing accumulation of H2O2, and improving the root activity. Of the studied organic acids, MA was much more efficient in mitigation of Cd toxicity than AA, probably by its antioxidant effects, which were stronger than those of AA. Plant response to Cd involved decreased production of endogenous LMWOA, probably as a consequence of severe Cd toxicity. The addition of MA or AA to the medium increased endogenous accumulation of LMWOA, especially in the roots, which could be beneficial for plant metabolism. These results imply that especially MA may be involved in the processes of Cd uptake, translocation, and tolerance in plants. PMID:26115548

  5. Purification by Immunoadsorption and Immunochemical Properties of NADP-Dependent Malic Enzymes from Leaves of C3, C4, and Crassulacean Acid Metabolism Plants

    PubMed Central

    Fathi, Marion; Schnarrenberger, Claus

    1990-01-01

    NADP:malic enzyme from corn (Zea mays L.) leaves was purified by conventional techniques to apparent homogeneity as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antibodies raised against this protein in rabbits were purified, coupled covalently to protein A-Sepharose CL-4B, and used as an immunoaffinity resin to purify the NADP:malic enzymes of the C3 plants spinach (Spinacia oleracea L.) and wheat (Triticum aestivum L.), of the Crassulacean acid metabolism (CAM) plant Bryophyllum daigremontianum R. Hamed et Perr. de la Bathie and the C4 plants corn, sugarcane (Saccharum officinarum L.), and Portulaca grandiflora L. Such procedures yielded homogeneous protein preparations with a single protein band, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, except for P. grandiflora L. with two bands. The specific activities of the purified proteins ranged between 56 and 91 units (milligrams per protein). NADP:malic enzyme represented up to 1% of the total soluble protein in C4 plants, 0.5% in the CAM plant, and less than 0.01% in C3 plants. In immunotitration tests involving immunoprecipitation and immunoinhibition of activity by an antiserum against the corn leaf enzyme, the NADP:malic enzymes of corn and sugarcane showed virtually full identity of epitopes, while the NADP:malic enzymes of the C3 and CAM plants exhibited a cross-reaction of one-twentieth and one-fourth by these tests, respectively. The NADP:malic enzyme of P. grandiflora exhibited characteristics more closely related to the enzymes of C3 and CAM plants than to those of C4 plants. Images Figure 1 Figure 2 PMID:16667339

  6. Intensification of β-poly(L: -malic acid) production by Aureobasidium pullulans ipe-1 in the late exponential growth phase.

    PubMed

    Cao, Weifeng; Luo, Jianquan; Zhao, Juan; Qiao, Changsheng; Ding, Luhui; Qi, Benkun; Su, Yi; Wan, Yinhua

    2012-07-01

    β-Poly(malic acid) (PMLA) has attracted industrial interest because this polyester can be used as a prodrug or for drug delivery systems. In PMLA production by Aureobasidium pullulans ipe-1, it was found that PLMA production was associated with cell growth in the early exponential growth phase and dissociated from cell growth in the late exponential growth phase. To enhance PMLA production in the late phase, different fermentation modes and strategies for controlling culture redox potential (CRP) were studied. The results showed that high concentrations of produced PMLA (above 40 g/l) not only inhibited PMLA production, but also was detrimental to cell growth. Moreover, when CRP increased from 57 to 100 mV in the late exponential growth phase, the lack of reducing power in the broth also decreased PMLA productivity. PMLA productivity could be enhanced by repeated-batch culture to maintain cell growth in the exponential growth phase, or by cell-recycle culture with membrane to remove the produced PMLA, or by maintaining CRP below 70 mV no matter which kind of fermentation mode was adopted. Repeated-batch culture afforded a high PMLA concentration (up to 63.2 g/l) with a productivity of 1.15 g l(-1) h(-1). Cell-recycle culture also confirmed that PMLA production by the strain ipe-1 was associated with cell growth.

  7. Systematic analysis of an evolved Thermobifida fusca muC producing malic acid on organic and inorganic nitrogen sources

    PubMed Central

    Deng, Yu; Lin, Jia; Mao, Yin; Zhang, Xiaojuan

    2016-01-01

    Thermobifida fusca is a thermophilic actinobacterium. T. fusca muC obtained by adaptive evolution preferred yeast extract to ammonium sulfate for accumulating malic acid and ammonium sulfate for cell growth. We did transcriptome analysis of T. fusca muC on Avicel and cellobiose with addition of ammonium sulfate or yeast extract, respectively by RNAseq. The transcriptional results indicate that ammonium sulfate induced the transcriptions of the genes related to carbohydrate metabolisms significantly more than yeast extract. Importantly, Tfu_2487, encoding histidine-containing protein (HPr), didn’t transcribe on yeast extract at all, while it transcribed highly on ammonium sulfate. In order to understand the impact of HPr on malate production and cell growth of the muC strain, we deleted Tfu_2487 to get a mutant strain: muCΔ2487, which had 1.33 mole/mole-glucose equivalent malate yield, much higher than that on yeast extract. We then developed an E. coli-T. fusca shuttle plasmid for over-expressing HPr in muCΔ2487, a strain without HPr background, forming the muCΔ2487S strain. The muCΔ2487S strain had a much lower malate yield but faster cell growth than the muC strain. The results of both mutant strains confirmed that HPr was the key regulatory protein for T. fusca’s metabolisms on nitrogen sources. PMID:27424527

  8. Natural and synthetic poly(malic acid)-based derivates: a family of versatile biopolymers for the design of drug nanocarriers.

    PubMed

    Loyer, Pascal; Cammas-Marion, Sandrine

    2014-08-01

    The field of specific drug delivery is an expanding research domain. Besides the use of liposomes formed from various lipids, natural and synthetic polymers have been developed to prepare more efficient drug delivery systems either under macromolecular prodrugs or under particulate nanovectors. To ameliorate the biocompatibility of such nanocarriers, degradable natural or synthetic polymers have attracted the interest of many researchers. In this context, poly(malic acid) (PMLA) extracted from microorganisms or synthesized from malic or aspartic acid was used to prepare water-soluble drug carriers or nanoparticles. Within this review, both the preparation and the applications of PMLA derivatives are described emphasizing the in vitro and in vivo assays. The results obtained by several groups highlight the interest of such polyesters in the field of drug delivery.

  9. Positive effect of reduced aeration rate on growth and stereospecificity of DL-malic acid consumption by Azospirillum brasilense: improving the shelf life of a liquid inoculant formulation.

    PubMed

    Carrasco-Espinosa, Karen; García-Cabrera, Ramsés I; Bedoya-López, Andrea; Trujillo-Roldán, Mauricio A; Valdez-Cruz, Norma A

    2015-02-10

    Azospirillum brasilense has significance as a growth promoter in plants of commercial interest. Two industrial native strains (Start and Calf), used as a part of an inoculant formulation in Mexico during the last 15 years, were incubated in laboratory-scale pneumatic bioreactors at different aeration rates. In both strains, the positive effect of decreased aeration was observed. At the lowest (0.1 vvm, air volume/liquid volume×minute), the highest biomass were obtained for Calf (7.8 × 10(10)CFU/ml), and Start (2.9 × 10(9)CFU/ml). These were higher in one magnitude order compared to cultures carried out at 0.5 vvm, and two compared to those at 1.0 vvm. At lower aeration, both stereoisomeric forms of malic acid were consumed, but at higher aeration, just L-malate was consumed. A reduction in aeration allows an increase of the shelf life and the microorganism saved higher concentrations of polyhydroxybutyrate. The selected fermentation conditions are closely related to those prevalent in large-scale bioreactors and offer the possibility of achieving high biomass titles with high shelf life at a reduced costs, due to the complete use of a carbon source at low aeration of a low cost raw material as DL-malic acid mixture in comparison with the L-malic acid stereoisomer.

  10. Absolute configuration of a chiral CHD group via neutron diffraction: confirmation of the absolute stereochemistry of the enzymatic formation of malic acid

    SciTech Connect

    Bau, R.; Brewer, I.; Chiang, M.Y.; Fujita, S.; Hoffman, J.; Watkins, M.I.; Koetzle, T.F.

    1983-09-30

    Neutron diffraction has been used to monitor the absolute stereochemistry of an enzymatic reaction. (-)(2S)malic-3-d acid was prepared by the action of fumarase on fumaric acid in D/sub 2/O. After a large number of cations were screened, it was found that (+)(R)..cap alpha..-phenylethylamine forms the large crystals necessary for a neutron diffraction analysis. The subsequent structure determination showed that (+)(R)..cap alpha..-phenylethylammonium (-)(2S)malate-3-d has an absolute configuration of R at the CHD site. This result confirms the absolute stereochemistry of fumarate-to-malate transformation as catalyzed by the enzyme fumarase.

  11. Preparation of poly(β-L-malic acid)-based charge-conversional nanoconjugates for tumor-specific uptake and cellular delivery.

    PubMed

    Zhou, Qing; Yang, Tiehong; Qiao, Youbei; Guo, Songyan; Zhu, Lin; Wu, Hong

    2015-01-01

    In this study, a multifunctional poly(β-L-malic acid)-based nanoconjugate with a pH-dependent charge conversional characteristic was developed for tumor-specific drug delivery. The short branched polyethylenimine-modified poly(β-L-malic acid) (PEPM) was first synthesized. Then, the fragment HAb18 F(ab')2 and 2,3-dimethylmaleic anhydride were covalently attached to the PEPM to form the nanoconjugate, HDPEPM. In this nanoconjugate, the 2,3-dimethylmaleic anhydride, the shielding group, could shield the positive charge of the conjugate at pH 7.4, while it was selectively hydrolyzed in the tumor extracellular space (pH 6.8) to expose the previously-shielded positive charge. To study the anticancer activity, the anticancer drug, doxorubicin, was covalently attached to the nanoconjugate. The doxorubicin-loaded HDPEPM nanoconjugate was able to efficiently undergo a quick charge conversion from -11.62 mV to 9.04 mV in response to the tumor extracellular pH. The electrostatic interaction between the positively charged HDPEPM nanoconjugates and the negatively charged cell membrane significantly enhanced their cellular uptake, resulting in the enhanced anticancer activity. Also, the tumor targetability of the nanoconjugates could be further improved via the fragment HAb18 F(ab')2 ligand-receptor-mediated tumor cell-specific endocytosis.

  12. The roles of Tyr(91) and Lys(162) in general acid-base catalysis in the pigeon NADP+-dependent malic enzyme.

    PubMed

    Kuo, Cheng-Chin; Lin, Kuan-Yu; Hsu, Yau-Jung; Lin, Shu-Yu; Lin, Yu-Tsen; Chang, Gu-Gang; Chou, Wei-Yuan

    2008-05-01

    The role of general acid-base catalysis in the enzymatic mechanism of NADP+-dependent malic enzyme was examined by detailed steady-state kinetic studies through site-directed mutagenesis of the Tyr(91) and Lys(162) residues in the putative catalytic site of the enzyme. Y91F and K162A mutants showed approx. 200- and 27000-fold decreases in k(cat) values respectively, which could be partially recovered with ammonium chloride. Neither mutant had an effect on the partial dehydrogenase activity of the enzyme. However, both Y91F and K162A mutants caused decreases in the k(cat) values of the partial decarboxylase activity of the enzyme by approx. 14- and 3250-fold respectively. The pH-log(k(cat)) profile of K162A was found to be different from the bell-shaped profile pattern of wild-type enzyme as it lacked a basic pK(a) value. Oxaloacetate, in the presence of NADPH, can be converted by malic enzyme into L-malate by reduction and into enolpyruvate by decarboxylation activities. Compared with wild-type, the K162A mutant preferred oxaloacetate reduction to decarboxylation. These results are consistent with the function of Lys(162) as a general acid that protonates the C-3 of enolpyruvate to form pyruvate. The Tyr(91) residue could form a hydrogen bond with Lys(162) to act as a catalytic dyad that contributes a proton to complete the enol-keto tautomerization.

  13. Synthesis and characterization of nanocrystalline forsterite coated poly(L-lactide-co-β-malic acid) scaffolds for bone tissue engineering applications.

    PubMed

    Mozafari, M; Gholipourmalekabadi, M; Chauhan, N P S; Jalali, N; Asgari, S; Caicedoa, J C; Hamlekhan, A; Urbanska, A M

    2015-05-01

    In this research, after synthesizing poly(L-lactide-co-β-malic acid) (PLMA) copolymer, hybrid particles of ice and nanocrystalline forsterite (NF) as coating carriers were used to prepare NF-coated PLMA scaffolds. The porous NF-coated scaffolds were directly fabricated by a combined technique using porogen leaching and freeze-drying methods. The obtained results indicate that the scaffolds were structurally porous with NF particles on their surfaces. When compared to the uncoated scaffolds, the NF coating improved both mechanical properties as well as enhanced bioactivity of the scaffolds. In addition, in vitro biological response of the rat bone marrow stromal cells indicated that NF significantly increased the biocompatibility of NF-coated scaffolds compared with PLMA.

  14. Effects of cooling rate, saturation temperature, and agitation on the metastable zone width of DL-malic acid-water system

    NASA Astrophysics Data System (ADS)

    Yuan, Ye; Leng, Yixin; Huang, Chunxiang; Yue, Mingxuan; Tan, Qian

    2015-09-01

    A study of metastable zone width (MSZW) and nucleation parameters for a cooling crystallization of DL-malic acid-water system is described in this paper. Experimental determination of the MSZW was performed using a laser method in order to carry out the estimation of nucleation parameters. Measured MSZWs can be affected by a variety of parameters, such as cooling rate, saturation temperature, agitation rate, and so on. In this work, the MSZWs were found to decrease with an increase of saturation temperature, and levels of agitation, while it increased with an increase of cooling rate. Two classical theoretical approaches, Nyvlt's approach and self-consistent Nyvlt-like approach were used to analyze the experimental data on MSZWs.

  15. Fumarate and cytosolic pH as modulators of the synthesis or consumption of C(4) organic acids through NADP-malic enzyme in Arabidopsis thaliana.

    PubMed

    Arias, Cintia Lucía; Andreo, Carlos Santiago; Drincovich, María Fabiana; Gerrard Wheeler, Mariel Claudia

    2013-02-01

    Arabidopsis thaliana is a plant species that accumulates high levels of organic acids and uses them as carbon, energy and reducing power sources. Among the enzymes that metabolize these compounds, one of the most important ones is malic enzyme (ME). A. thaliana contains four malic enzymes (NADP-ME 1-4) to catalyze the reversible oxidative decarboxylation of malate in the presence of NADP. NADP-ME2 is the only one located in the cell cytosol of all Arabidopsis organs providing most of the total NADP-ME activity. In the present work, the regulation of this key enzyme by fumarate was investigated by kinetic assays, structural analysis and a site-directed mutagenesis approach. The final effect of this metabolite on NADP-ME2 forward activity not only depends on fumarate and substrate concentrations but also on the pH of the reaction medium. Fumarate produced an increase in NADP-ME2 activity by binding to an allosteric site. However at higher concentrations, fumarate caused a competitive inhibition, excluding the substrate malate from binding to the active site. The characterization of ME2-R115A mutant, which is not activated by fumarate, confirms this hypothesis. In addition, the reverse reaction (reductive carboxylation of pyruvate) is also modulated by fumarate, but in a different way. The results indicate pH-dependence of the fumarate modulation with opposite behavior on the two activities analyzed. Thereby, the coordinated action of fumarate over the direct and reverse reactions would allow a precise and specific modulation of the metabolic flux through this enzyme, leading to the synthesis or degradation of C(4) compounds under certain conditions. Thus, the physiological context might be exerting an accurate control of ME activity in planta, through changes in metabolite and substrate concentrations and cytosolic pH.

  16. High molecular weight β-poly(L-malic acid) produced by A. pullulans with Ca²⁺ added repeated batch culture.

    PubMed

    Cao, Weifeng; Chen, Xiangrong; Luo, Jianquan; Yin, Junxiang; Qiao, Changsheng; Wan, Yinhua

    2016-04-01

    β-Poly(malic acid) (PMLA) has attracted increasing attentions because of its potential application in medicine and other industries. In this study, the variation of PMLA molecular weight (Mw) in the batch culture and the strategies to enhance PMLA Mw were studied. Adding exogenous Ca(2+) (0.1g/L CaCl2) to the medium caused a significant increase in both PMLA concentration and Mw (11.38% and 26.3%, respectively) when Na2CO3 was used as the neutralizer. The Mw of PMLA during the process of batch culture, which associated with the specific PMLA production per unit cell mass (Yp/x) before glucose was depleted, increased from 12.522 KDa to its maximum 18.693 KDa and then kept decreasing until the end of the culture. Compared with the results in batch culture, Mw increased by 84.4% (up to 19.51 kDa) with a productivity of 1.1 gh(-1)L(-1) when the cells were maintained in exponential growth phase during Ca(2+) added repeated batch culture. The present work provides an efficient approach to obtain superior quality PMLA product with high Mw.

  17. Triggering Apoptotic Death of Human Epidermal Keratinocytes by Malic Acid: Involvement of Endoplasmic Reticulum Stress- and Mitochondria-Dependent Signaling Pathways

    PubMed Central

    Hsiao, Yu-Ping; Lai, Wan-Wen; Wu, Shi-Bei; Tsai, Chung-Hung; Tang, Sheau-Chung; Chung, Jing-Gung; Yang, Jen-Hung

    2015-01-01

    Malic acid (MA) has been commonly used in cosmetic products, but the safety reports in skin are sparse. To investigate the biological effects of MA in human skin keratinocytes, we investigated the potential cytotoxicity and apoptotic effects of MA in human keratinocyte cell lines (HaCaT). The data showed that MA induced apoptosis based on the observations of DAPI staining, DNA fragmentation, and sub-G1 phase in HaCaT cells and normal human epidermal keratinocytes (NHEKs). Flow cytometric assays also showed that MA increased the production of mitochondrial superoxide (mito-SOX) but decreased the mitochondrial membrane potential. Analysis of bioenergetics function with the XF 24 analyzer Seahorse extracellular flux analyzer demonstrated that oxygen consumption rate (OCR) was significantly decreased whereas extracellular acidification rate (ECAR) was increased in MA-treated keratinocytes. The occurrence of apoptosis was proved by the increased expressions of FasL, Fas, Bax, Bid, caspases-3, -8, -9, cytochrome c, and the declined expressions of Bcl-2, PARP. MA also induced endoplasmic reticulum stress associated protein expression such as GRP78, GADD153, and ATF6α. We demonstrated that MA had anti-proliferative effect in HaCaT cell through the inhibition of cell cycle progression at G0/G1, and the induction of programmed cell death through endoplasmic reticulum stress- and mitochondria-dependent pathways. PMID:25584429

  18. Analysis of ATP-citrate lyase and malic enzyme mutants of Yarrowia lipolytica points out the importance of mannitol metabolism in fatty acid synthesis.

    PubMed

    Dulermo, Thierry; Lazar, Zbigniew; Dulermo, Rémi; Rakicka, Magdalena; Haddouche, Ramedane; Nicaud, Jean-Marc

    2015-09-01

    The role of the two key enzymes of fatty acid (FA) synthesis, ATP-citrate lyase (Acl) and malic enzyme (Mae), was analyzed in the oleaginous yeast Yarrowia lipolytica. In most oleaginous yeasts, Acl and Mae are proposed to provide, respectively, acetyl-CoA and NADPH for FA synthesis. Acl was mainly studied at the biochemical level but no strain depleted for this enzyme was analyzed in oleaginous microorganisms. On the other hand the role of Mae in FA synthesis in Y. lipolytica remains unclear since it was proposed to be a mitochondrial NAD(H)-dependent enzyme and not a cytosolic NADP(H)-dependent enzyme. In this study, we analyzed for the first time strains inactivated for corresponding genes. Inactivation of ACL1 decreases FA synthesis by 60 to 80%, confirming its essential role in FA synthesis in Y. lipolytica. Conversely, inactivation of MAE1 has no effects on FA synthesis, except in a FA overaccumulating strain where it improves FA synthesis by 35%. This result definitively excludes Mae as a major key enzyme for FA synthesis in Y. lipolytica. During the analysis of both mutants, we observed a negative correlation between FA and mannitol level. As mannitol and FA pathways may compete for carbon storage, we inactivated YlSDR, encoding a mannitol dehydrogenase converting fructose and NADPH into mannitol and NADP+. The FA content of the resulting mutant was improved by 60% during growth on fructose, demonstrating that mannitol metabolism may modulate FA synthesis in Y. lipolytica.

  19. Apple juice composition: sugar, nonvolatile acid, and phenolic profiles.

    PubMed

    Lee, H S; Wrolstad, R E

    1988-01-01

    Apples from Michigan, Washington, Argentina, Mexico, and New Zealand were processed into juice; the 8 samples included Golden Delicious, Jonathan, Granny Smith, and McIntosh varieties. Liquid chromatography was used for quantitation of sugars (glucose, fructose, sucrose, and sorbitol), nonvolatile acids (malic, quinic, citric, shikimic, and fumaric), and phenolics (chlorogenic acid and hydroxymethylfurfural [HMF]). Other determinations included pH, 0Brix, and L-malic acid. A number of compositional indices for these authentic juices, e.g., chlorogenic acid content, total malic - L-malic difference, and the HMF:chlorogenic ratio, were at variance with recommended standards. The phenolic profile was shown to be particularly influenced by gelatin fining, with peak areas decreasing by as much as 50%. The L-malic:total malic ratio serves as a better index for presence of synthetic malic acid than does the difference between the 2 determinations. No apparent differences in chemical composition could be attributed to geographic origin.

  20. Temporal Variations of Organic Acids in Sumac Fruit

    SciTech Connect

    Robbins, C.; Mulcahy, F.; Somayajula, K.; Edenborn, H.M.

    2006-10-01

    Extracts from staghorn sumac (Rhus typhina) fruits were obtained from fresh fruits obtained from June to October in two successive years. Total acidity, pH, and concentrations of malic and succinic acids determined using liquid chromatography were measured for each extract. Acidity and acid concentrations reached their maxima in late July, and declined slowly thereafter. Malic and succinic acid concentrations in the extracts reached maxima of about 4 and 0.2% (expressed per unit weight of fruit), respectively. Malic and succinic acids were the only organic acids observed in the extracts, and mass balance determinations indicate that these acids are most likely the only ones present in appreciable amounts.

  1. Uncovering co-expression gene network regulating fruit acidity in diverse apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acidity is a major contributor to fruit quality. Several organic acids are present in apple fruit, but malic acid is predominant and determines fruit acidity. The trait is largely controlled by the Malic acid (Ma) locus, underpinning which Ma1 that encodes an Aluminum-activated Malate Transporter1 (...

  2. [Effect of organic acids on the biosynthesis of carotenes by an Actinomyces chrysomallus strain].

    PubMed

    Nefelova, M V; Sverdlova, A N; Alekseeva, L N

    1978-01-01

    Synthesis of carotenes by Actinomyces chrysomallus var. carotenoides was stimulated by citric, acetic, oxalacetic, fumaric, succinic, malic, alpha-ketoglutaric, tartaric, pyruvic, and propionic acids. Acetic acid acts as a precursor of carotene synthesis and also has another stimulating mechanism of action on carotenogenesis of the actinomycete. Acetic, furmaric, malic, succinic, and alpha-ketoglutaric acids stimulate cyclization of lycopene yielding beta-carotene.

  3. [Organic acids of various kinds of vegetables. IV. Changes in the acids and sugar in tomatoes, sweet peppers and cucumbers during development and ripening].

    PubMed

    Tarrach, F; Herrmann, K

    1986-12-01

    Concentrations of organic acids and sugars in tomatoes and sweet peppers change notably during ripening. The concentration of malic acid decreases while that of citric acid increases considerably and in redripe fruits clearly exceeds the content of malic acid. Several maxima and minima in acid concentrations occur during development. Both species show constant proportions of citric and isocitric acid (200:1 and 30:1 respectively). In sweet pepper, quinic and ascorbic acid can be found in noticeably higher amounts than in tomatoes. Additionally, succinic acid was detected in tomatoes and fumaric and shikimic acid in sweet pepper. Glucose and fructose, in approximately equal amounts, are the main sugar components; their concentrations are increased during ripening, especially in sweet peppers. The leaves of tomatoes and sweet pepper contain more malic acid and less citric acid than redripe fruits, though here as well citric acid predominates. There is considerably less glucose and fructose present in the leaves of sweet pepper than in the fruits while sucrose is increased. Sucrose is the main sugar component in the leaves. Compared to tomatoes and sweet peppers, egg-plants contain more amounts. - Potatoes contain citric, malic, quinic, succinic, fumaric, and soluble oxalic acid (in order of decreasing amounts). - In cucumbers malic acid notably exceeds citric acid. Both acids hardly change in concentration during ripening. Sugar content decreases during ripening. PMID:3811599

  4. [Organic acids of various kinds of vegetables. IV. Changes in the acids and sugar in tomatoes, sweet peppers and cucumbers during development and ripening].

    PubMed

    Tarrach, F; Herrmann, K

    1986-12-01

    Concentrations of organic acids and sugars in tomatoes and sweet peppers change notably during ripening. The concentration of malic acid decreases while that of citric acid increases considerably and in redripe fruits clearly exceeds the content of malic acid. Several maxima and minima in acid concentrations occur during development. Both species show constant proportions of citric and isocitric acid (200:1 and 30:1 respectively). In sweet pepper, quinic and ascorbic acid can be found in noticeably higher amounts than in tomatoes. Additionally, succinic acid was detected in tomatoes and fumaric and shikimic acid in sweet pepper. Glucose and fructose, in approximately equal amounts, are the main sugar components; their concentrations are increased during ripening, especially in sweet peppers. The leaves of tomatoes and sweet pepper contain more malic acid and less citric acid than redripe fruits, though here as well citric acid predominates. There is considerably less glucose and fructose present in the leaves of sweet pepper than in the fruits while sucrose is increased. Sucrose is the main sugar component in the leaves. Compared to tomatoes and sweet peppers, egg-plants contain more amounts. - Potatoes contain citric, malic, quinic, succinic, fumaric, and soluble oxalic acid (in order of decreasing amounts). - In cucumbers malic acid notably exceeds citric acid. Both acids hardly change in concentration during ripening. Sugar content decreases during ripening.

  5. Folic Acid

    MedlinePlus

    Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

  6. Folic Acid

    MedlinePlus

    Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by ... Folic acid comes in tablets. It usually is taken once a day. Follow the directions on your prescription label ...

  7. Amino acids

    MedlinePlus

    ... amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan , and valine. Nonessential amino acids "Nonessential" means that our bodies produce an amino ...

  8. Acid Rain.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  9. Acid rain

    SciTech Connect

    Not Available

    1985-01-01

    This report has four parts: they discuss acid rain in relation to acid soils, agriculture, forests, and aquatic ecosystems. Among findings: modern sources of acid deposition from the atmosphere for all the acid soils in the world, nor even chiefly responsible for those of northern U.S. Agriculture has its problems, but acid precipitation is probably not one of them. More research is needed to determine to what extent acid precipitation is responsible for forest declines and for smaller detrimental effects on forest growth where no damage to the foliage is evident. Many lakes and streams are extremely sensitive to added acids.

  10. Aminocaproic Acid

    MedlinePlus

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

  11. Ethacrynic Acid

    MedlinePlus

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

  12. Aristolochic Acids

    MedlinePlus

    ... Sciences NIH-HHS www.niehs.nih.gov Aristolochic Acids Key Points Report on Carcinogens Status Known to be human carcinogens Aristolochia Clematitis Aristolochic Acids n Known human carcinogens n Found in certain ...

  13. Obeticholic Acid

    MedlinePlus

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

  14. Acid mucopolysaccharides

    MedlinePlus

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

  15. Quantification of organic acids using voltammetric tongues.

    PubMed

    Escobar, Juan David; Alcaniz, Miguel; Masot, Rafael; Fuentes, Ana; Bataller, Roman; Soto, Juan; Barat, Jose Manuel

    2013-06-01

    Recently, electronic tongues (ET) have appeared as an excellent alternative to traditional techniques for the evaluation of food quality and processes. ET systems are based on arrays of low selectivity sensors that are simultaneously sensitive to several components in a measured sample (cross-sensitivity). The aim of this study was to determine the ability of an ET based on pulse voltammetry to quantify organic acids (ascorbic, citric and malic acids) in simple (SS) and binary solutions (BS) using different electrodes. The most significant electrodes for ascorbic acid prediction were Ni and Ag for SS, and Ag and Ir for BS where positive pulses were more suitable than negative ones. The prediction of citric and malic acids in SS and BS were suitable using Ir, Rh, Pt, Ag and Cu electrodes, using both positive and negative pulses.

  16. HPLC method for the simultaneous quantification of the major organic acids in Angeleno plum fruit

    NASA Astrophysics Data System (ADS)

    Wang, Yanwei; Wang, Jing; Cheng, Wei; Zhao, Zhilei; Cao, Jiankang

    2014-08-01

    A method was developed to profile major organic acids in Angeleno fruit by high performance liquid chromatography. Organic acids in plum were extracted by water with ultra- sonication at 50°C for 30 min. The extracts were chromatographed on Waters Atlantis T3 C18 column (4.6 mm×250 mm, 5 μm) with 0.01mol/L sulfuric acid and water as mobile phase, and flow rate was 0.5 ml/min. The column temperature was 40C, and chromatography was monitored by a diode array detector at 210 nm. The result showed that malic acid, citric acid, tartaric acid, oxalic acid, pyruvic acid, acetic acid, succinic acid in Angeleno plum, and the malic acid was the major organic acids. The coefficient of determination of the standard calibration curve is R2 > 0.999. The organic acids recovery ranged from 99.11% for Malic acid to 106.70% for Oxalic acid, and CV (n=6) ranged from 0.95% for Malic acid to 6.23% for Oxalic acid, respectively. The method was accurate, sensitive and feasible in analyzing the organic acids in Angeleno plum.

  17. Fatty acids - trans fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. Interconversion of biologically important carboxylic acids by radiation

    NASA Technical Reports Server (NTRS)

    Negron-Mendoza, A.; Ponnamperuma, C.

    1978-01-01

    The interconversion of a group of biologically important polycarboxylic acids (acetic, fumaric, malic, malonic, succinic, citric, isocitric, tricarballylic) under gamma-ray or ultraviolet radiation was investigated. The formation of high molecular weight compounds was observed in all cases. Succinic acid was formed in almost all radiolysis experiments. Citric, malonic, and succinic acids appeared to be relatively insensitive to radiation. Interconversion of the polycarboxylic acids studied may have occurred under the effect of radiation in the prebiotic earth.

  19. Aspartic acid

    MedlinePlus

    ... Hormone production and release Normal nervous system function Plant sources of aspartic acid include: Legumes such as soybeans, garbanzo beans, and lentils Peanuts, almonds, walnuts, and flaxseeds Animal ...

  20. Production of Succinic Acid from Citric Acid and Related Acids by Lactobacillus Strains

    PubMed Central

    Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

    1988-01-01

    A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, α-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli. PMID:16347795

  1. Usnic acid.

    PubMed

    Ingólfsdóttir, K

    2002-12-01

    Since its first isolation in 1844, usnic acid [2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione] has become the most extensively studied lichen metabolite and one of the few that is commercially available. Usnic acid is uniquely found in lichens, and is especially abundant in genera such as Alectoria, Cladonia, Usnea, Lecanora, Ramalina and Evernia. Many lichens and extracts containing usnic acid have been utilized for medicinal, perfumery, cosmetic as well as ecological applications. Usnic acid as a pure substance has been formulated in creams, toothpaste, mouthwash, deodorants and sunscreen products, in some cases as an active principle, in others as a preservative. In addition to antimicrobial activity against human and plant pathogens, usnic acid has been shown to exhibit antiviral, antiprotozoal, antiproliferative, anti-inflammatory and analgesic activity. Ecological effects, such as antigrowth, antiherbivore and anti-insect properties, have also been demonstrated. A difference in biological activity has in some cases been observed between the two enantiomeric forms of usnic acid. Recently health food supplements containing usnic acid have been promoted for use in weight reduction, with little scientific support. The emphasis of the current review is on the chemistry and biological activity of usnic acid and its derivatives in addition to rational and ecologically acceptable methods for provision of this natural compound on a large scale.

  2. Acid rain

    SciTech Connect

    Elsworth, S.

    1985-01-01

    This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

  3. Acid rain

    SciTech Connect

    White, J.C. )

    1988-01-01

    This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

  4. How Acidic Is Carbonic Acid?

    PubMed

    Pines, Dina; Ditkovich, Julia; Mukra, Tzach; Miller, Yifat; Kiefer, Philip M; Daschakraborty, Snehasis; Hynes, James T; Pines, Ehud

    2016-03-10

    Carbonic, lactic, and pyruvic acids have been generated in aqueous solution by the transient protonation of their corresponding conjugate bases by a tailor-made photoacid, the 6-hydroxy-1-sulfonate pyrene sodium salt molecule. A particular goal is to establish the pK(a) of carbonic acid H2CO3. The on-contact proton transfer (PT) reaction rate from the optically excited photoacid to the carboxylic bases was derived, with unprecedented precision, from time-correlated single-photon-counting measurements of the fluorescence lifetime of the photoacid in the presence of the proton acceptors. The time-dependent diffusion-assisted PT rate was analyzed using the Szabo-Collins-Kimball equation with a radiation boundary condition. The on-contact PT rates were found to follow the acidity order of the carboxylic acids: the stronger was the acid, the slower was the PT reaction to its conjugate base. The pK(a) of carbonic acid was found to be 3.49 ± 0.05 using both the Marcus and Kiefer-Hynes free energy correlations. This establishes H2CO3 as being 0.37 pK(a) units stronger and about 1 pK(a) unit weaker, respectively, than the physiologically important lactic and pyruvic acids. The considerable acid strength of intact carbonic acid indicates that it is an important protonation agent under physiological conditions. PMID:26862781

  5. Acid rain

    SciTech Connect

    Sweet, W.

    1980-06-20

    Acid precipitation includes not only rain but also acidified snow, hail and frost, as well as sulfur and nitrogen dust. The principal source of acid precipitation is pollution emitted by power plants and smelters. Sulfur and nitrogen compounds contained in the emissions combine with moisture to form droplets with a high acid content - sometimes as acidic as vinegar. When sufficiently concentrated, these acids can kill fish and damage material structures. Under certain circumstances they may reduce crop and forest yields and cause or aggravate respiratory diseases in humans. During the summer, especially, pollutants tend to collect over the Great Lakes in high pressure systems. Since winds typically are westerly and rotate clockwise around high pressure systems, the pollutants gradually are dispersed throughout the eastern part of the continent.

  6. Asparagusic acid.

    PubMed

    Mitchell, Stephen C; Waring, Rosemary H

    2014-01-01

    Asparagusic acid (1,2-dithiolane-4-carboxylic acid) is a simple sulphur-containing 5-membered heterocyclic compound that appears unique to asparagus, though other dithiolane derivatives have been identified in non-food species. This molecule, apparently innocuous toxicologically to man, is the most probable culprit responsible for the curious excretion of odorous urine following asparagus ingestion. The presence of the two adjacent sulphur atoms leads to an enhanced chemical reactivity, endowing it with biological properties including the ability to substitute potentially for α-lipoic acid in α-keto-acid oxidation systems. This brief review collects the scattered data available in the literature concerning asparagusic acid and highlights its properties, intermediary metabolism and exploratory applications.

  7. Acid rain

    SciTech Connect

    Bess, F.D.

    1980-01-01

    The acid rain problem in the northeastern U.S. has been growing in severity and geographical areas affected. Acid rain has damaged, or will result in damage to visibility, physical structures and materials, aquatic life, timber, crops, and soils. The principal causes of acid rain in the northeastern U.S. are sulfur oxide and nitrogen oxide emissions from large power plants and smelters in the Ohio River Valley. Immediate corrective action and appropriate research are needed to reduce acid precipitation. Short-term programs that will define the rate of environmental deterioration, remaining environmental capacity to resist sudden deterioration, mechanisms of acid rain formation, and costs of various control options must be developed. (3 maps, 13 references, 1 table)

  8. Asparagusic acid.

    PubMed

    Mitchell, Stephen C; Waring, Rosemary H

    2014-01-01

    Asparagusic acid (1,2-dithiolane-4-carboxylic acid) is a simple sulphur-containing 5-membered heterocyclic compound that appears unique to asparagus, though other dithiolane derivatives have been identified in non-food species. This molecule, apparently innocuous toxicologically to man, is the most probable culprit responsible for the curious excretion of odorous urine following asparagus ingestion. The presence of the two adjacent sulphur atoms leads to an enhanced chemical reactivity, endowing it with biological properties including the ability to substitute potentially for α-lipoic acid in α-keto-acid oxidation systems. This brief review collects the scattered data available in the literature concerning asparagusic acid and highlights its properties, intermediary metabolism and exploratory applications. PMID:24099657

  9. Increase in the permeability of tonoplast of garlic (Allium sativum) by monocarboxylic acids.

    PubMed

    Bai, Bing; Li, Lei; Hu, Xiaosong; Wang, Zhengfu; Zhao, Guanghua

    2006-10-18

    Immersion of intact aged garlic (Allium sativum) cloves in a series of 5% weak organic monocarboxylate solutions (pH 2.0) resulted in green color formation. No color was formed upon treatment with other weak organic acids, such as citric and malic acids, and the inorganic hydrochloric acid under the same conditions. To understand the significance of monocarboxylic acids and their differing function from that of other acids, acetic acid was compared with organic acids citric and malic and the inorganic hydrochloric acid. The effects of these acids on the permeability of plasma and intracellular membrane of garlic cells were measured by conductivity, light microscopy, and transmission electron microscopy. Except for hydrochloric acid, treatment of garlic with all three organic acids greatly increased the relative conductivity of their respective pickling solutions, indicating that all tested organic acids increased the permeability of plasma membrane. Moreover, a pickling solution containing acetic acid exhibited 1.5-fold higher relative conductivity (approximately 90%) as compared to those (approximately 60%) of both citric and malic acids, implying that exposure of garlic cloves to acetic acid not only changed the permeability of the plasma membrane but also increased the permeability of intracellular membrane. Exposure of garlic to acetic acid led to the production of precipitate along the tonoplast, but no precipitate was formed by citric and malic acids. This indicates that the structure of the tonoplast was damaged by this treatment. Further support for this conclusion comes from results showing that the concentration of thiosulfinates [which are produced only by catalytic conversion of S-alk(en)yl-l-cysteine sulfoxides in cytosol by alliinase located in the vacuole] in the acetic acid pickling solution is 1.3 mg/mL, but almost no thiosulfinates were detected in the pickling solution of citric and malic acids. Thus, all present results suggest that damage of

  10. Acid fog

    SciTech Connect

    Hileman, B.

    1983-03-01

    Fog in areas of southern California previously thought to be pollution-free has been shown to have a pH as low as 1.69. It has been found to be most acidic after smoggy days, suggesting that it forms on the aerosol associated with the previously exiting smog. Studies on Whiteface Mountain in the Adirondacks show that fog water is often 10 times as acidic as rainwater. As a result of their studies, California plans to spend $4 million on acid deposition research in the coming year. (JMT)

  11. Tranexamic Acid

    MedlinePlus

    ... is used to treat heavy bleeding during the menstrual cycle (monthly periods) in women. Tranexamic acid is in ... tablets for more than 5 days in a menstrual cycle or take more than 6 tablets in a ...

  12. Mefenamic Acid

    MedlinePlus

    ... as mefenamic acid may cause ulcers, bleeding, or holes in the stomach or intestine. These problems may ... like coffee grounds, blood in the stool, or black and tarry stools.Keep all appointments with your ...

  13. Acid Precipitation

    ERIC Educational Resources Information Center

    Likens, Gene E.

    1976-01-01

    Discusses the fact that the acidity of rain and snow falling on parts of the U.S. and Europe has been rising. The reasons are still not entirely clear and the consequences have yet to be well evaluated. (MLH)

  14. Acidic precipitation

    SciTech Connect

    Martin, H.C.

    1987-01-01

    At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

  15. In vitro antilisterial effects of citrus oil fractions in combination with organic acids.

    PubMed

    Friedly, E C; Crandall, P G; Ricke, S C; Roman, M; O'Bryan, C; Chalova, V I

    2009-03-01

    The objectives of this study were to screen activity of citrus essential oil fractions (EOs) alone and in combination with organic acids against 2 species of Listeria. Five citrus EOs were initially screened by disc diffusion assay for antibacterial activity. Cold pressed terpeneless Valencia orange oil (CP terpeneless oil) had the strongest bacteriostatic (MIC) and bactericidal (MBC) properties at 0.55% and 1.67%, respectively. Four organic acids were tested for effectiveness against Listeria. Citric and malic acids proved to be the most effective with MBC of 1.1% alone. Assays were conducted to determine synergistic effects of EOs and citric or malic acids. There was a significant decrease in MIC and MBC to 0.04% EO plus 0.12% malic or citric acid. EOs from citrus paired with organic acids offer the potential as an all-natural antimicrobial for improving the safety of all-natural foods. PMID:19323760

  16. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  17. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  18. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  19. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  20. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  1. Salicylic acids

    PubMed Central

    Hayat, Shamsul; Irfan, Mohd; Wani, Arif; Nasser, Alyemeni; Ahmad, Aqil

    2012-01-01

    Salicylic acid is well known phytohormone, emerging recently as a new paradigm of an array of manifestations of growth regulators. The area unleashed yet encompassed the applied agriculture sector to find the roles to strengthen the crops against plethora of abiotic and biotic stresses. The skipped part of integrated picture, however, was the evolutionary insight of salicylic acid to either allow or discard the microbial invasion depending upon various internal factors of two interactants under the prevailing external conditions. The metabolic status that allows the host invasion either as pathogenesis or symbiosis with possible intermediary stages in close systems has been tried to underpin here. PMID:22301975

  2. The hygroscopic properties of dicarboxylic and multifunctional acids: measurements and UNIFAC predictions.

    PubMed

    Peng, C; Chan, M N; Chan, C K

    2001-11-15

    The role of water-soluble organic compounds on the hygroscopic properties of atmospheric aerosols has recently been the subject of many studies. In particular, low molecular weight dicarboxylic acids and some multifunctional organic acids have been found or are expected to exist in atmospheric aerosols in urban, semiurban, rural, and remote sites. Unlike for their inorganic counterparts, the hygroscopic properties of organic acids have not been well characterized. In this study, the hygroscopic properties of selected water-soluble dicarboxylic acids (oxalic acid, malonic acid, succinic acid, and glutaric acid) and multifunctional acids (citric acid, DL-malic acid, and L-(+)-tartaric acid) were studied using single droplets levitated in an electrodynamic balance at 25 degrees C. The water activities of bulk samples of dilute solutions were also measured. Solute evaporation was observed in the dicarboxylic acids but not in the multifunctional acids. Oxalic acid, succinic acid, and glutaric acid droplets crystallize upon evaporation of water, but, except for glutaric acid droplets, do not deliquesce even at 90% relative humidity (RH). Mass transfer limitation of the deliquescence process was observed in glutaric acid. Neither crystallization nor deliquescence was observed in malonic acid, citric acid, DL-malic acid, or L-(+)-tartaric acid. Malonic acid and these three hydroxy-carboxylic acids absorb water even at RH much lower than their respective deliquescence RH. The growth factor (Gf), defined as the ratio of the particle diameter at RH = 10% to that at RH = 90%, of oxalic acid and succinic acid was close to unity, indicating no hygroscopicity in this range. The remaining acids (malonic acid, glutaric acid, citric acid, malic acid, and tartaric acid) showed roughly similar hygroscopicity of a Gf of 1.30-1.53, which is similar to that of "more hygroscopic" aerosols in field measurements reported in the literature. A generalized equation for these four acids, Gf

  3. Metabolic engineering in the biotechnological production of organic acids in the tricarboxylic acid cycle of microorganisms: Advances and prospects.

    PubMed

    Yin, Xian; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Liu, Long; Chen, Jian

    2015-11-01

    Organic acids, which are chemically synthesized, are also natural intermediates in the metabolic pathways of microorganisms, among which the tricarboxylic acid (TCA) cycle is the most crucial route existing in almost all living organisms. Organic acids in the TCA cycle include citric acid, α-ketoglutaric acid, succinic acid, fumaric acid, l-malic acid, and oxaloacetate, which are building-block chemicals with wide applications and huge markets. In this review, we summarize the synthesis pathways of these organic acids and review recent advances in metabolic engineering strategies that enhance organic acid production. We also propose further improvements for the production of organic acids with systems and synthetic biology-guided metabolic engineering strategies.

  4. Crystal and molecular structure of eight organic acid-base adducts from 2-methylquinoline and different acids

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Jin, Shouwen; Tao, Lin; Liu, Bin; Wang, Daqi

    2014-08-01

    Eight supramolecular complexes with 2-methylquinoline and acidic components as 4-aminobenzoic acid, 2-aminobenzoic acid, salicylic acid, 5-chlorosalicylic acid, 3,5-dinitrosalicylic acid, malic acid, sebacic acid, and 1,5-naphthalenedisulfonic acid were synthesized and characterized by X-ray crystallography, IR, mp, and elemental analysis. All of the complexes are organic salts except compound 2. All supramolecular architectures of 1-8 involve extensive classical hydrogen bonds as well as other noncovalent interactions. The results presented herein indicate that the strength and directionality of the classical hydrogen bonds (ionic or neutral) between acidic components and 2-methylquinoline are sufficient to bring about the formation of binary organic acid-base adducts. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, the complexes 1-8 displayed 2D-3D framework structure.

  5. Stearic Acid

    ERIC Educational Resources Information Center

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) is presented for the chemical, stearic acid. The profile lists the chemical's physical and harmful characteristics, exposure limits, and symptoms of major exposure, for the benefit of teachers and students, who use the chemical in the laboratory.

  6. Trichloroacetic acid

    Integrated Risk Information System (IRIS)

    Trichloroacetic acid ( TCA ) ; CASRN 76 - 03 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Nonca

  7. Acrylic acid

    Integrated Risk Information System (IRIS)

    Acrylic acid ( CASRN 79 - 10 - 7 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  8. Selenious acid

    Integrated Risk Information System (IRIS)

    Selenious acid ; CASRN 7783 - 00 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  9. Dichloroacetic acid

    Integrated Risk Information System (IRIS)

    Dichloroacetic acid ; CASRN 79 - 43 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  10. Cacodylic acid

    Integrated Risk Information System (IRIS)

    Cacodylic acid ; CASRN 75 - 60 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  11. Phosphoric acid

    Integrated Risk Information System (IRIS)

    Phosphoric acid ; CASRN 7664 - 38 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  12. Benzoic acid

    Integrated Risk Information System (IRIS)

    Benzoic acid ; CASRN 65 - 85 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  13. Formic acid

    Integrated Risk Information System (IRIS)

    Formic acid ; CASRN 64 - 18 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effect

  14. [Hyaluronic acid].

    PubMed

    Pomarede, N

    2008-01-01

    Hyaluronic Acid (HA) is now a leader product in esthetic procedures for the treatment of wrinkles and volumes. The structure of HA, its metabolism, its physiological function are foremost breaking down then its use in aesthetic dermatology: steps of injection, possible side effects, benefits and downsides of the use of HA in aesthetic dermatology.

  15. Fixation of Carbon Dioxide in the Dark by the Malic Enzyme of Bean and Oat Stem Rust Uredospores 1

    PubMed Central

    Rick, P. D.; Mirocha, C. J.

    1968-01-01

    Malic enzyme was found in both bean rust and cat stem rust uredospores. In bean rust uredospores it was shown to catalyze the formation of pyruvic acid from l-malic acid and to synthesize malic acid from pyruvic acid and CO2. The malic enzyme from bean rust uredospores was specific for NADP and dependent on manganous ions for activity. The specific activity of the bean rust malic enzyme in crude extracts of ungerminated uredospores was approximately 6 times greater than that found in crude extracts obtained from germinated uredospores. The malic enzyme was also found in extracts obtained from healthy and rust-infected bean leaves. The specific activity of the enzyme was approximately 2 to 5 times greater in partially purified extracts obtained from the infected bean tissue at 6 days after inoculation. The specific activity of the malic enzyme in crude extracts obtained from oat stem rust uredospores was 2 times greater than the specific activity of this enzyme in crude extracts obtained from bean rust uredospores. Phosphoenolpyruvate carboxylase activity could not be demonstrated in crude extracts obtained from the ungerminated uredospores of the bean rust fungus. PMID:16656752

  16. Hydroxycarboxylic acids and salts

    DOEpatents

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

    2015-02-24

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

  17. Effects of organic acids, amino acids and ethanol on the radio-degradation of patulin in an aqueous model system

    NASA Astrophysics Data System (ADS)

    Yun, Hyejeong; Lim, Sangyong; Jo, Cheorun; Chung, Jinwoo; Kim, Soohyun; Kwon, Joong-Ho; Kim, Dongho

    2008-06-01

    The effects of organic acids, amino acids, and ethanol on the radio-degradation of patulin by gamma irradiation in an aqueous model system were investigated. The patulin, dissolved in distilled water at a concentration of 50 ppm, was practically degraded by the gamma irradiation at the dose of 1.0 kGy, while 33% of the patulin remained in apple juice. In the aqueous model system, the radio-degradation of patulin was partially inhibited by the addition of organic acids, amino acids, and ethanol. The proportions of remaining patulin after irradiation with the dose of 1.0 kGy in the 1% solution of malic acid, citric acid, lactic acid, acetic acid, ascorbic acid, and ethanol were 31.4%, 2.3%, 31.2%, 6.1%, 50.8%, and 12.5%, respectively. During 30 days of storage, the remaining patulin was reduced gradually in the solution of ascorbic acid and malic acid compared to being stable in other samples. The amino acids, serine, threonine, and histidine, inhibited the radio-degradation of patulin. In conclusion, it was suggested that 1 kGy of gamma irradiation (recommended radiation doses for radicidation and/or quarantine in fruits) is effective for the reduction of patulin, but the nutritional elements should be considered because the radio-degradation effects are environment dependent.

  18. Methylmalonic acid blood test

    MedlinePlus

    ... acid is a substance produced when proteins, called amino acids, in the body break down. The health care ... Cederbaum S, Berry GT. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Devaskar ...

  19. Folic Acid and Pregnancy

    MedlinePlus

    ... 5 Things to Know About Zika & Pregnancy Folic Acid and Pregnancy KidsHealth > For Parents > Folic Acid and ... before conception and during early pregnancy . About Folic Acid Folic acid, sometimes called folate, is a B ...

  20. Understanding Acid Rain

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  1. Dynamic dielectric properties of some carboxylic acid esters in benzene solution

    NASA Astrophysics Data System (ADS)

    Ghoneim, Ahmed M.; Stockhause, Martina; Becker, U.; Biedenkap, R.; Elsebrock, R.

    1997-06-01

    The dielectric absorption spectrum between some MHz and 36 GHz has been measured at 20 degrees C for S(-)-lactic acid methylester, succinic acid dimethylester, L(-)- malic acid dimethylester and L(+)-tartaric acid diethylester, over the whole concentration range of benzene solutions of these substances. The loss function can be described by up to four Debye type spectral components. The relaxation parameters are reported and discussed in particular with respect to association effects.

  2. Isotope effect studies of the chemical mechanism of nicotinamide adenine dinucleotide malic enzyme from Crassula

    SciTech Connect

    Grissom, C.B.; Willeford, O.; Wedding, R.T.

    1987-05-05

    The /sup 13/C primary kinetic isotope effect on the decarboxylation of malate by nicotinamide adenine dinucleotide malic enzyme from Crassula argentea is 1.0199 +/- 0.0006 with proteo L-malate-2-H and 1.0162 +/- 0.0003 with malate-2-d. The primary deuterium isotope effect is 1.45 +/- 0.10 on V/K and 1.93 +/- 0.13 on V/sub max/. This indicates a stepwise conversion of malate to pyruvate and CO/sub 2/ with hydride transfer preceding decarboxylation, thereby suggesting a discrete oxaloacetate intermediate. This is in agreement with the stepwise nature of the chemical mechanism of other malic enzymes despite the Crassula enzyme's inability to reduce or decarboxylate oxaloacetate. Differences in morphology and allosteric regulation between enzymes suggest specialization of the Crassula malic enzyme for the physiology of crassulacean and acid metabolism while maintaining the catalytic events founds in malic enzymes from animal sources.

  3. Separation of membranes from acid-solubilized fish muscle proteins with the aid of calcium ions and organic acids.

    PubMed

    Liang, Yong; Hultin, Herbert O

    2005-04-20

    Calcium chloride, and to a lesser extent MgCl2, aided in the separation of membranes by centrifugation from cod (Gadus morhua) muscle homogenates solubilized at pH 3 in the presence of citric acid or malic acid but not lactic acid. Adding citric acid and Ca2+ before solubilizing the cod muscle homogenates was needed for the effect. At 1 mM citric acid, 70-80% of the phospholipid and 25-30% of the protein were removed at 10 mM Ca2+. At 8 mM Ca2+, citric acid showed an optimal effect on phospholipid removal at 5 mM with 90% of the phospholipid and 35% of the protein removed. The treatment with citric acid and Ca2+ was also effective in separating the membrane from solubilized herring (Clupea harengus) muscle homogenate. Ca2+ and citric acid might exert their influence by disconnecting linkages between membranes and cytoskeletal proteins.

  4. Extraction chemistry of fermentation product carboxylic acid

    SciTech Connect

    Kertes, A.S.; King, C.J.

    1986-02-01

    Within the framework of a program aiming to improve the existing extractive recovery technology of fermentation products, the state of the art is critically reviewed. The acids under consideration are propionic, lactic, pyruvic, succinic, fumaric, maleic, malic, itaconic, tartaric, citric, and isocitric, all obtained by the aerobic fermentation of glucose via the glycolytic pathway and glyoxylate bypass. With no exception, it is the undissociated monomeric acid that is extracted into carbon-bonded and phosphorus-bonded oxygen donor extractants. In the organic phase, the acids are usually dimerized. The extractive transfer process obeys the Nernst law, and the measured partition coefficients range from about 0.003 for aliphatic hydrocarbons to about 2 to 3 for aliphatic alcohols and ketones to about 10 or more for organophosphates. Equally high distribution ratios are measured when long-chain tertiary amines are employed as extractants, forming bulky salts preferentially soluble in the organic phase. 123 references.

  5. Removal of lead by apatite and its stability in the presence of organic acids.

    PubMed

    Katoh, Masahiko; Makimura, Akihiko; Sato, Takeshi

    2016-12-01

    In this study, lead sorption and desorption tests were conducted with apatite and organic acids (i.e. citric, malic, and formic acids) to understand lead removal by apatite in the presence of an organic acid and lead dissolution from the lead- and organic-acid-sorbed apatite by such organic acid exposure. The lead sorption test showed that the amount of lead removed by apatite in the presence of organic acid varied depending on the type of acid used. The molar amounts of calcium dissolved from apatite in the presence and absence of organic acid were exactly the same as those of lead removed even under different pH conditions as well as different organic acid concentrations, indicating that the varying amount of lead removal in the presence of different organic acids resulted from the magnitude of the dissolution of apatite and the precipitation of lead phosphate minerals. The percentages of lead dissolved from the organic-acid-sorbed and non-organic-acid-sorbed apatite by all the organic acid extractions were equal and higher than those by water extraction. In particular, the highest extractions were observed in the non-organic-acid-sorbed apatite by citric and malic acids. These results suggest that to immobilize lead by the use of apatite in the presence of organic acids, much more apatite must be added than in the absence of organic acid, and that measures must be taken to ensure that the immobilized lead is not dissolved.

  6. Precipitation: its acidic nature.

    PubMed

    Frohliger, J O; Kane, R

    1975-08-01

    A comparison of the free hydrogen ion concentration and the total hydrogen ion concentration of rain samples shows that rain is a weak acid. The weak acid nature of rain casts doubt on the concepts that the acidity of rain is increasing and that these increases are due to strong acids such as sulfuric acid.

  7. Amino Acid Metabolism Disorders

    MedlinePlus

    ... defects & other health conditions > Amino acid metabolism disorders Amino acid metabolism disorders E-mail to a friend Please ... baby’s newborn screening may include testing for certain amino acid metabolism disorders. These are rare health conditions that ...

  8. Carbolic acid poisoning

    MedlinePlus

    Phenol poisoning; Phenylic acid poisoning; Hydroxybenzene poisoning; Phenic acid poisoning; Benzenol poisoning ... Below are symptoms of carbolic acid poisoning in different parts of the ... urine Decreased urine output No urine output EYES, EARS, ...

  9. Azelaic Acid Topical

    MedlinePlus

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

  10. Uric acid test (image)

    MedlinePlus

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

  11. Facts about Folic Acid

    MedlinePlus

    ... Information For... Media Policy Makers Facts About Folic Acid Language: English Español (Spanish) Recommend on Facebook Tweet ... of the baby's brain and spine. About folic acid Folic acid is a B vitamin. Our bodies ...

  12. Acid Lipase Disease

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage ... Trials Related NINDS Publications and Information What is Acid Lipase Disease ? Acid lipase disease or deficiency occurs ...

  13. Process characterization and influence of alternative carbon sources and carbon-to-nitrogen ratio on organic acid production by Aspergillus oryzae DSM1863.

    PubMed

    Ochsenreither, Katrin; Fischer, Christian; Neumann, Anke; Syldatk, Christoph

    2014-06-01

    L-Malic acid and fumaric acid are C4 dicarboxylic organic acids and considered as promising chemical building blocks. They can be applied as food preservatives and acidulants in rust removal and as polymerization starter units. Molds of the genus Aspergillus are able to produce malic acid in large quantities from glucose and other carbon sources. In order to enhance the production potential of Aspergillus oryzae DSM 1863, production and consumption rates in an established bioreactor batch-process based on glucose were determined. At 35 °C, up to 42 g/L malic acid was produced in a 168-h batch process with fumaric acid as a by-product. In prolonged shaking flask experiments (353 h), the suitability of the alternative carbon sources xylose and glycerol at a carbon-to-nitrogen (C/N) ratio of 200:1 and the influence of different C/N ratios in glucose cultivations were tested. When using glucose, 58.2 g/L malic acid and 4.2 g/L fumaric acid were produced. When applying xylose or glycerol, both organic acids are produced but the formation of malic acid decreased to 45.4 and 39.4 g/L, respectively. Whereas the fumaric acid concentration was not significantly altered when cultivating with xylose (4.5 g/L), it is clearly enhanced by using glycerol (9.3 g/L). When using glucose as a carbon source, an increase or decrease of the C/N ratio did not influence malic acid production but had an enormous influence on fumaric acid production. The highest fumaric acid concentrations were determined at the highest C/N ratio (300:1, 8.44 g/L) and lowest at the lowest C/N ratio (100:1, 0.7 g/L).

  14. Unidirectional inhibition and activation of "malic' enzyme of Solanum tuberosum by meso-tartrate.

    PubMed

    Do Nascimento, K H; Davies, D D; Patil, K D

    1975-08-01

    A kinetic study of "malic' enzyme (EC 1.1.1.40) from potato suggests that the mechanism is Ordered Bi Ter with NADP+ binding before malate, and NADPH binding before pyruvate and HCO3-. The analysis is complicated by the non-linearity that occurs in some of the plots. meso-Tartrate is shown to inhibit the oxidative decarboxylation of malate but to activate the reductive carboxylation of pyruvate. To explain these unidirectional effects it is suggested that the control site of "malic' enzyme binds organic acids (including meso-tartrate) which activate the enzyme. meso-Tartrate, however, competes with malate for the active site and thus inhibits the oxidative decarboxylation of malate. Because meso-tartrate does not compete effectively with pyruvate for enzyme-NADPH, its binding at the control site leads to a stimulation of the carboxylation of pyruvate. A similar explanation is advanced for the observation that malic acid stimulates its own synthesis.

  15. Acid distribution in phosphoric acid fuel cells

    SciTech Connect

    Okae, I.; Seya, A.; Umemoto, M.

    1996-12-31

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

  16. Mobilization of soil-borne arsenic by three common organic acids: Dosage and time effects.

    PubMed

    Onireti, Olaronke O; Lin, Chuxia

    2016-03-01

    A batch experiment was conducted to investigate the mobilization of soil-borne arsenic by three common low-molecular-weight organic acids with a focus on dosage and time effects. The results show that oxalic acid behaved differently from citric acid and malic acid in terms of mobilizing As that was bound to iron compounds. At an equivalent molar concentration, reactions between oxalic acid and soil-borne Fe were kinetically more favourable, as compared to those between either citric acid or malic acid and the soil-borne Fe. It was found that reductive dissolution of soil-borne Fe played a more important role in liberating As, as compared to non-reductive reactions. Prior to the 7th day of the experiment, As mobility increased with increasing dose of oxalic acid while there was no significant difference (P > 0.05) in mobilized As among the treatments with different doses of citric acid or malic acid. The dosage effect on soil-borne As mobilization in the citric acid and malic acid treatments became clear only after the 7th day of the experiment. Soluble Ca present in the soils could cause re-immobilization of As by competing with solution-borne Fe for available organic ligands to form practically insoluble organic compounds of calcium (i.e. calcium oxalate). This resulted in transformation of highly soluble organic complexes of iron (i.e. iron oxalate complexes) into slightly soluble organic compounds of iron (i.e. iron oxalate) or free ferric ion, which then reacted with the solution-borne arsenate ions to form practically insoluble iron arsenates in the latter part of the experiment.

  17. Mobilization of soil-borne arsenic by three common organic acids: Dosage and time effects.

    PubMed

    Onireti, Olaronke O; Lin, Chuxia

    2016-03-01

    A batch experiment was conducted to investigate the mobilization of soil-borne arsenic by three common low-molecular-weight organic acids with a focus on dosage and time effects. The results show that oxalic acid behaved differently from citric acid and malic acid in terms of mobilizing As that was bound to iron compounds. At an equivalent molar concentration, reactions between oxalic acid and soil-borne Fe were kinetically more favourable, as compared to those between either citric acid or malic acid and the soil-borne Fe. It was found that reductive dissolution of soil-borne Fe played a more important role in liberating As, as compared to non-reductive reactions. Prior to the 7th day of the experiment, As mobility increased with increasing dose of oxalic acid while there was no significant difference (P > 0.05) in mobilized As among the treatments with different doses of citric acid or malic acid. The dosage effect on soil-borne As mobilization in the citric acid and malic acid treatments became clear only after the 7th day of the experiment. Soluble Ca present in the soils could cause re-immobilization of As by competing with solution-borne Fe for available organic ligands to form practically insoluble organic compounds of calcium (i.e. calcium oxalate). This resulted in transformation of highly soluble organic complexes of iron (i.e. iron oxalate complexes) into slightly soluble organic compounds of iron (i.e. iron oxalate) or free ferric ion, which then reacted with the solution-borne arsenate ions to form practically insoluble iron arsenates in the latter part of the experiment. PMID:26774299

  18. Organic acid contents in onion cultivars (Allium cepa L.).

    PubMed

    Rodríguez Galdón, Beatriz; Tascón Rodríguez, Catalina; Rodríguez Rodríguez, Elena; Díaz Romero, Carlos

    2008-08-13

    The following organic acids (glutamic, oxalic, pyruvic, malic, tartaric, citric, and fumaric), pungency, Brix degree, acidity, and pH were determined in onion cultivars (Texas, Guayonje, San Juan de la Rambla, Carrizal Alto, Carrizal Bajo, and Masca) harvested in the same agroclimatic conditions. Glutamic acid was the most abundant organic acid (325 +/- 133 mg/100 g) followed by citric acid (48.5 +/- 24.1 mg/100 g) and malic acid (43.6 +/- 10.4 mg/100 g). There were significant differences between the onion cultivars in the mean concentrations of all of the analyzed parameters. The San Juan de la Rambla and Masca cultivars presented, in general, higher concentrations of the organic acids than the other cultivars. Significant differences in most of the analyzed parameters were observed between the two seed origins for the Masca and San Juan de la Rambla cultivars. The onion samples tended to be classified according to the cultivar and, in the case of San Juan de la Rambla cultivar, according to the precedence of the seeds after applying discriminant analysis. PMID:18616262

  19. Effects of organic acids on thermal inactivation of acid and cold stressed Enterococcus faecium.

    PubMed

    Fernández, Ana; Alvarez-Ordóñez, Avelino; López, Mercedes; Bernardo, Ana

    2009-08-01

    In this study the adaptative response to heat (70 degrees C) of Enterococcus faecium using fresh and refrigerated (at 4 degrees C for up to 1 month) stationary phase cells grown in Brain Heart Infusion (BHI) buffered at pH 7.4 (non-acid-adapted cells) and acidified BHI at pH values of 6.4 and 5.4 with acetic, ascorbic, citric, lactic, malic and hydrochloric acids (acid-adapted cells) was evaluated. In all cases, the survival curves obtained were concave upward. A mathematical model based on the Weibull distribution accurately described the inactivation kinetic. The results indicate that previous adaptation to a low pH increased the bacterial heat resistance, whereas the subsequent cold storage of cells reduced E. faecium thermal tolerance. Fresh acid-adapted cells showed t(2.5)-values (time needed to obtain an inactivation level of 2.5 log10 cycles) ranging from 2.57 to 9.51 min, while non-acid-adapted cells showed t(2.5)-values of 1.92 min. The extent of increased heat tolerance varied with the acid examined, resulting in the following order: citric > or = acetic > malic > or = lactic > hydrochloric > or = ascorbic. In contrast, cold storage progressively decreased E. faecium thermal resistance. The t(2.5) values found at the end of the period studied were about 2-3-fold lower than those corresponding to non-refrigerated cells, although this decrease was more marked (about 5-fold) when cells were grown in buffered BHI and BHI acidified at pH 5.4 with hydrochloric acid. These findings highlight the need for a better understanding of microbial response to various preservation stresses in order to increase the efficiency of thermal processes and to indicate the convenience of counterbalancing the benefits of the hurdle concept.

  20. The Roles of Organic Acids in C4 Photosynthesis

    PubMed Central

    Ludwig, Martha

    2016-01-01

    Organic acids are involved in numerous metabolic pathways in all plants. The finding that some plants, known as C4 plants, have four-carbon dicarboxylic acids as the first product of carbon fixation showed these organic acids play essential roles as photosynthetic intermediates. Oxaloacetate (OAA), malate, and aspartate (Asp) are substrates for the C4 acid cycle that underpins the CO2 concentrating mechanism of C4 photosynthesis. In this cycle, OAA is the immediate, short-lived, product of the initial CO2 fixation step in C4 leaf mesophyll cells. The malate and Asp, resulting from the rapid conversion of OAA, are the organic acids delivered to the sites of carbon reduction in the bundle-sheath cells of the leaf, where they are decarboxylated, with the released CO2 used to make carbohydrates. The three-carbon organic acids resulting from the decarboxylation reactions are returned to the mesophyll cells where they are used to regenerate the CO2 acceptor pool. NADP-malic enzyme-type, NAD-malic enzyme-type, and phosphoenolpyruvate carboxykinase-type C4 plants were identified, based on the most abundant decarboxylating enzyme in the leaf tissue. The genes encoding these C4 pathway-associated decarboxylases were co-opted from ancestral C3 plant genes during the evolution of C4 photosynthesis. Malate was recognized as the major organic acid transferred in NADP-malic enzyme-type C4 species, while Asp fills this role in NAD-malic enzyme-type and phosphoenolpyruvate carboxykinase-type plants. However, accumulating evidence indicates that many C4 plants use a combination of organic acids and decarboxylases during CO2 fixation, and the C4-type categories are not rigid. The ability to transfer multiple organic acid species and utilize different decarboxylases has been suggested to give C4 plants advantages in changing and stressful environments, as well as during development, by facilitating the balance of energy between the two cell types involved in the C4 pathway of CO2

  1. The Roles of Organic Acids in C4 Photosynthesis.

    PubMed

    Ludwig, Martha

    2016-01-01

    Organic acids are involved in numerous metabolic pathways in all plants. The finding that some plants, known as C4 plants, have four-carbon dicarboxylic acids as the first product of carbon fixation showed these organic acids play essential roles as photosynthetic intermediates. Oxaloacetate (OAA), malate, and aspartate (Asp) are substrates for the C4 acid cycle that underpins the CO2 concentrating mechanism of C4 photosynthesis. In this cycle, OAA is the immediate, short-lived, product of the initial CO2 fixation step in C4 leaf mesophyll cells. The malate and Asp, resulting from the rapid conversion of OAA, are the organic acids delivered to the sites of carbon reduction in the bundle-sheath cells of the leaf, where they are decarboxylated, with the released CO2 used to make carbohydrates. The three-carbon organic acids resulting from the decarboxylation reactions are returned to the mesophyll cells where they are used to regenerate the CO2 acceptor pool. NADP-malic enzyme-type, NAD-malic enzyme-type, and phosphoenolpyruvate carboxykinase-type C4 plants were identified, based on the most abundant decarboxylating enzyme in the leaf tissue. The genes encoding these C4 pathway-associated decarboxylases were co-opted from ancestral C3 plant genes during the evolution of C4 photosynthesis. Malate was recognized as the major organic acid transferred in NADP-malic enzyme-type C4 species, while Asp fills this role in NAD-malic enzyme-type and phosphoenolpyruvate carboxykinase-type plants. However, accumulating evidence indicates that many C4 plants use a combination of organic acids and decarboxylases during CO2 fixation, and the C4-type categories are not rigid. The ability to transfer multiple organic acid species and utilize different decarboxylases has been suggested to give C4 plants advantages in changing and stressful environments, as well as during development, by facilitating the balance of energy between the two cell types involved in the C4 pathway of CO2

  2. Acid tolerance in amphibians

    SciTech Connect

    Pierce, B.A.

    1985-04-01

    Studies of amphibian acid tolerance provide information about the potential effects of acid deposition on amphibian communities. Amphibians as a group appear to be relatively acid tolerant, with many species suffering increased mortality only below pH 4. However, amphibians exhibit much intraspecific variation in acid tolerance, and some species are sensitive to even low levels of acidity. Furthermore, nonlethal effects, including depression of growth rates and increases in developmental abnormalities, can occur at higher pH.

  3. Bioconversions of ferulic acid, an hydroxycinnamic acid.

    PubMed

    Mathew, Sindhu; Abraham, T Emilia

    2006-01-01

    Ferulic acid is the most abundant hydroxycinnamic acid in the plant world and is ester linked to arabinose, in various plant polysaccharides such as arabinoxylans and pectins. It is a precursor to vanillin, one of the most important aromatic flavor compound used in foods, beverages, pharmaceuticals, and perfumes. This article presents an overview of the various biocatalytic routes, focusing on the relevant biotransformations of ferulic acid using plant sources, microorganisms, and enzymes.

  4. Crassulacean acid metabolism photosynthesis: ;working the night shift'.

    PubMed

    Black, Clanton C; Osmond, C Barry

    2003-01-01

    Crassulacean acid metabolism (CAM) can be traced from Roman times through persons who noted a morning acid taste of some common house plants. From India in 1815, Benjamin-Heyne described a 'daily acid taste cycle' with some succulent garden plants. Recent work has shown that the nocturnally formed acid is decarboxylated during the day to become the CO(2) for photosynthesis. Thus, CAM photosynthesis extends over a 24-hour day using several daily interlocking cycles. To understand CAM photosynthesis, several landmark discoveries were made at the following times: daily reciprocal acid and carbohydrate cycles were found during 1870 to 1887; their precise identification, as malic acid and starch, and accurate quantification occurred from 1940 to 1954; diffusive gas resistance methods were introduced in the early 1960s that led to understanding the powerful stomatal control of daily gas exchanges; C(4) photosynthesis in two different types of cells was discovered from 1965 to approximately 1974 and the resultant information was used to elucidate the day and night portions of CAM photosynthesis in one cell; and exceptionally high internal green tissue CO(2) levels, 0.2 to 2.5%, upon the daytime decarboxylation of malic acid, were discovered in 1979. These discoveries then were combined with related information from C(3) and C(4) photosynthesis, carbon biochemistry, cellular anatomy, and ecological physiology. Therefore by approximately 1980, CAM photosynthesis finally was rigorously outlined. In a nutshell, 24-hour CAM occurs by phosphoenol pyruvate (PEP) carboxylase fixing CO(2)(HCO(3) (-)) over the night to form malic acid that is stored in plant cell vacuoles. While stomata are tightly closed the following day, malic acid is decarboxylated releasing CO(2) for C(3) photosynthesis via ribulose bisphosphate carboxylase oxygenase (Rubisco). The CO(2) acceptor, PEP, is formed via glycolysis at night from starch or other stored carbohydrates and after decarboxylation the

  5. What controls fleshy fruit acidity? A review of malate and citrate accumulation in fruit cells.

    PubMed

    Etienne, A; Génard, M; Lobit, P; Mbeguié-A-Mbéguié, D; Bugaud, C

    2013-04-01

    Fleshy fruit acidity is an important component of fruit organoleptic quality and is mainly due to the presence of malic and citric acids, the main organic acids found in most ripe fruits. The accumulation of these two acids in fruit cells is the result of several interlinked processes that take place in different compartments of the cell and appear to be under the control of many factors. This review combines analyses of transcriptomic, metabolomic, and proteomic data, and fruit process-based simulation models of the accumulation of citric and malic acids, to further our understanding of the physiological mechanisms likely to control the accumulation of these two acids during fruit development. The effects of agro-environmental factors, such as the source:sink ratio, water supply, mineral nutrition, and temperature, on citric and malic acid accumulation in fruit cells have been reported in several agronomic studies. This review sheds light on the interactions between these factors and the metabolism and storage of organic acids in the cell.

  6. Application of edible coating and acidic washing for extending the storage life of mushrooms (Agaricus bisporus).

    PubMed

    Sedaghat, Naser; Zahedi, Younes

    2012-12-01

    Hydrocolloid-based materials have been extensively used to coat fruit and vegetables to prolong shelf-life. The effects of different concentrations of acidic washing (acetic, ascorbic, citric and malic acids) followed by coating with gum arabic (GA), carboxymethyl cellulose and emulsified gum arabic (EGA) were evaluated on the weight loss (WL), firmness and color of mushroom. The WL of the uncoated mushrooms was significantly (p < 0.05) greater than that of the coated ones, and the minimum WL was obtained with EGA coating. The mushrooms washed with malic and ascorbic acids showed minimum and maximum of WL, respectively. Loss in firmness of the EGA-coated mushrooms was by 21% (the minimum of loss), while loss value of the uncoated ones was by 39% (the maximum of loss). Firmness of mushrooms was not influenced by the acid type. Concentration of the acid significantly (p < 0.05) influenced the firmness of mushrooms, and at the lowest concentration of acid (1%), the mushrooms tissue was firmest. The L* value of the mushrooms coated with GA was higher than that of others. A significant (p < 0.05) decrease in L* value and a significant (p < 0.05) increase in a* and b* values occurred in the mushrooms washed with acetic acid. Overall, washing with 1% citric or malic acid followed by coating with EGA resulted in minimum decrease in WL and firmness of the mushrooms.

  7. Plums (Prunus domestica L.) are a good source of yeasts producing organic acids of industrial interest from glycerol.

    PubMed

    García-Fraile, Paula; Silva, Luís R; Sánchez-Márquez, Salud; Velázquez, Encarna; Rivas, Raúl

    2013-08-15

    The production of organic acids from several yeasts isolated from mature plums on media containing glycerol as carbon source was analysed by HPLC-UV. The yeasts isolated were identified by sequencing the 5.8S internal transcribed spacer as Pichia fermentans, Wickerhamomyces anomalus and Candida oleophila. The organic acid profiles of these strains comprise acetic, citric, succinic and malic acids that qualitatively and quantitatively vary between different species as well as among strains from the same species. The production from glycerol of succinic, acetic, citric, malic and oxalic acids from C. oleophila and W. anomalus, and that of succinic, oxalic and acetic acids by P. fermentans is reported for the first time in this work, as is the production of oxalic acid from glycerol in yeasts. Our results also showed that mature fruits can be a good source of new yeasts able to metabolise glycerol, producing different organic acids with industrial and biotechnological interest.

  8. Reduction of Cr (VI) by organic acids in the presence of Al (III).

    PubMed

    Chen, Na; Lan, Yeqing; Wang, Bo; Mao, Jingdong

    2013-09-15

    The effects of Al (III) on the reduction of Cr (VI) by three α-hydroxy acids, tartaric, malic and citric acids, were investigated through batch experiments at pH from 2.5 to 4.0 and temperatures from 25 °C to 35 °C. These reactions could be described as pseudo-zero-order with respect to Cr (VI) when the concentrations of α-hydroxy acids were greatly in excess. The transformation rates of Cr (VI) to Cr (III) in the presence of Al (III) without light were in the decreasing order of tartaric acid>malic acid>citric acid. This order suggested that the two α-hydroxyl groups in tartaric acid could play an important role in the reduction of Cr (VI) by organic acids. The possible mechanism was that the formed complex between organic acids and Al (III) significantly enhanced the reductivity of α-hydroxy acids and further led to the more complicated Cr (VI)-tartaric acid-Al (III) cyclic ester which greatly accelerated the reduction rate. The Cr (VI) reduction reaction rate increased with the decrease of pH but with the increase of Al (III) concentration, tartaric acid concentration, and temperature. As the pH decreased, the increase of [H(+)] led to an increase in {Al(III)H₂Tar₂}(+), the most active species, and thus the enhanced reduction rate.

  9. Acid Thunder: Acid Rain and Ancient Mesoamerica

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  10. Quantity of acid in acid fog

    SciTech Connect

    Deal, W.J.

    1983-07-01

    This communication notes the actual magnitude of the acidity in acidic fog particles and suggests a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air.

  11. Gamma irradiation of isocitric and citric acid in aqueous solution: Relevance in prebiotic chemistry

    SciTech Connect

    Negrón-Mendoza, A. Ramos-Bernal, S.

    2015-07-23

    The radiation chemistry of hydroxy acids like citric and isocitric acids is rather scarce, even though they are crucial compounds in biological systems and for food irradiation. The aim of this work is to study the radiolytic behavior of these acids focused on the interconversion induced by radiation of citric and isocitric acid into other members of the Krebs cycle. The results showed that among the products formed were succinic, malonic, malic and other acids related to metabolic pathways, and these results are correlated with its possible role in chemical evolution processes.

  12. Gamma irradiation of isocitric and citric acid in aqueous solution: Relevance in prebiotic chemistry

    NASA Astrophysics Data System (ADS)

    Negrón-Mendoza, A.; Ramos-Bernal, S.

    2015-07-01

    The radiation chemistry of hydroxy acids like citric and isocitric acids is rather scarce, even though they are crucial compounds in biological systems and for food irradiation. The aim of this work is to study the radiolytic behavior of these acids focused on the interconversion induced by radiation of citric and isocitric acid into other members of the Krebs cycle. The results showed that among the products formed were succinic, malonic, malic and other acids related to metabolic pathways, and these results are correlated with its possible role in chemical evolution processes.

  13. Deletion of glucose oxidase changes the pattern of organic acid production in Aspergillus carbonarius.

    PubMed

    Yang, Lei; Lübeck, Mette; Lübeck, Peter S

    2014-01-01

    Aspergillus carbonarius has potential as a cell factory for the production of different organic acids. At pH 5.5, A.carbonarius accumulates high amounts of gluconic acid when it grows on glucose based medium whereas at low pH, it produces citric acid. The conversion of glucose to gluconic acid is carried out by secretion of the enzyme, glucose oxidase. In this work, the gene encoding glucose oxidase was identified and deleted from A. carbonarius with the aim of changing the carbon flux towards other organic acids. The effect of genetic engineering was examined by testing glucose oxidase deficient (Δgox) mutants for the production of different organic acids in a defined production medium. The results obtained showed that the gluconic acid accumulation was completely inhibited and increased amounts of citric acid, oxalic acid and malic acid were observed in the Δgox mutants.

  14. Lactic acid test

    MedlinePlus

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

  15. Omega-6 Fatty Acids

    MedlinePlus

    ... types of fats. Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean ... from studying specific omega-6 fatty acids or plant oils containing omega-6 fatty acids. See the separate ...

  16. Fatty acid analogs

    DOEpatents

    Elmaleh, David R.; Livni, Eli

    1985-01-01

    In one aspect, a radioactively labeled analog of a fatty acid which is capable of being taken up by mammalian tissue and which exhibits an in vivo beta-oxidation rate below that with a corresponding radioactively labeled fatty acid.

  17. Deoxycholic Acid Injection

    MedlinePlus

    Deoxycholic acid injection is used to improve the appearance and profile of moderate to severe submental fat ('double chin'; fatty tissue located under the chin). Deoxycholic acid injection is in a class of medications called ...

  18. Aminocaproic Acid Injection

    MedlinePlus

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

  19. Zoledronic Acid Injection

    MedlinePlus

    ... acid (Reclast) is used to prevent or treat osteoporosis (condition in which the bones become thin and ... Zoledronic acid (Reclast) is also used to treat osteoporosis in men, and to prevent or treat osteoporosis ...

  20. Uric Acid Test

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? Uric Acid Share this page: Was this page helpful? Also known as: Serum Urate; UA Formal name: Uric Acid Related tests: Synovial Fluid Analysis , Kidney Stone Analysis , ...

  1. Methylmalonic Acid Test

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? Methylmalonic Acid Share this page: Was this page helpful? Also known as: MMA Formal name: Methylmalonic Acid Related tests: Vitamin B12 and Folate , Homocysteine , Intrinsic ...

  2. Hydrochloric acid poisoning

    MedlinePlus

    Hydrochloric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe ... discusses poisoning due to swallowing or breathing in hydrochloric acid. This article is for information only. Do ...

  3. Mixed Acid Oxidation

    SciTech Connect

    Pierce, R.A.

    1999-10-26

    Several non-thermal processes have been developed to destroy organic waste compounds using chemicals with high oxidation potentials. These efforts have focused on developing technologies that work at low temperatures, relative to incineration, to overcome many of the regulatory issues associated with obtaining permits for waste incinerators. One such technique with great flexibility is mixed acid oxidation. Mixed acid oxidation, developed at the Savannah River Site, uses a mixture of an oxidant (nitric acid) and a carrier acid (phosphoric acid). The carrier acid acts as a non-volatile holding medium for the somewhat volatile oxidant. The combination of acids allows appreciable amounts of the concentrated oxidant to remain in the carrier acid well above the oxidant''s normal boiling point.

  4. Regulatory properties of malic enzyme in the oleaginous yeast, Yarrowia lipolytica, and its non-involvement in lipid accumulation.

    PubMed

    Zhang, Huaiyuan; Zhang, Luning; Chen, Haiqin; Chen, Yong Q; Ratledge, Colin; Song, Yuanda; Chen, Wei

    2013-12-01

    Malic enzyme (EC 1.1.1.40) converts L-malate to pyruvate and CO2 providing NADPH for metabolism especially for lipid biosynthesis in oleaginous microorganisms. However, its role in the oleaginous yeast, Yarrowia lipolytica, is unclear. We have cloned the malic enzyme gene (YALI0E18634g) from Y. lipolytica into pET28a, expressed it in Escherichia coli and purified the recombinant protein (YlME). YlME used NAD(+) as the primary cofactor. Km values for NAD(+) and NADP(+) were 0.63 and 3.9 mM, respectively. Citrate, isocitrate and α-ketoglutaric acid (>5 mM) were inhibitory while succinate (5-15 mM) increased NADP(+)- but not NAD(+)-dependent activity. To determine if fatty acid biosynthesis could be increased in Y. lipolytica by providing additional NADPH from an NADP(+)-dependent malic enzyme, the malic enzyme gene (mce2) from an oleaginous fungus, Mortierella alpina, was expressed in Y. lipolytica. No significant changes occurred in lipid content or fatty acid profiles suggesting that malic enzyme is not the main source of NADPH for lipid accumulation in Y. lipolytica.

  5. Plant fatty acid hydroxylases

    DOEpatents

    Somerville, Chris; Broun, Pierre; van de Loo, Frank

    2001-01-01

    This invention relates to plant fatty acyl hydroxylases. Methods to use conserved amino acid or nucleotide sequences to obtain plant fatty acyl hydroxylases are described. Also described is the use of cDNA clones encoding a plant hydroxylase to produce a family of hydroxylated fatty acids in transgenic plants. In addition, the use of genes encoding fatty acid hydroxylases or desaturases to alter the level of lipid fatty acid unsaturation in transgenic plants is described.

  6. PRODUCTION OF TRIFLUOROACETIC ACID

    DOEpatents

    Haworth, W.N.; Stacey, M.

    1949-07-19

    A method is given for the production of improved yields of trifluoroacetic acid. The compound is prepared by oxidizing m-aminobenzotrifluoride with an alkali metal or alkaline earth metal permanganate at a temperature in the range of 80 deg C to 100 deg C while dissolved ln a mixture of water with glacial acetic acid and/or trifluoroacetic acid. Preferably a mixture of water and trifluoroacetic acid ls used as the solvent.

  7. Quantity of acid in acid fog

    SciTech Connect

    Deal, W.J.

    1983-07-01

    The chemical composition of fog particles has become of considerable interest, because of both the possibility of interpreting atmospheric- chemistry processes in fog particles in terms of the principles of aqueous chemistry and the potential health effects of species present in fog particles. The acidity of fog particles has received wide attention. This communication noted the actual magnitude of the excess acidity in acidic fog particles and suggested a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air. (DP)

  8. Acid Rain Study Guide.

    ERIC Educational Resources Information Center

    Hunger, Carolyn; And Others

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

  9. The Acid Rain Reader.

    ERIC Educational Resources Information Center

    Stubbs, Harriett S.; And Others

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

  10. What Is Acid Rain?

    ERIC Educational Resources Information Center

    Likens, Gene E.

    2004-01-01

    Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

  11. [alpha]-Oxocarboxylic Acids

    ERIC Educational Resources Information Center

    Kerber, Robert C.; Fernando, Marian S.

    2010-01-01

    Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

  12. Hypotensive and toxicological study of citric acid and other constituents from Tagetes patula roots.

    PubMed

    Saleem, Rubeena; Ahmad, Mohammad; Naz, Aneela; Siddiqui, Humaira; Ahmad, Syed Iqbal; Faizi, Shaheen

    2004-10-01

    Study of the effects of the methanolic extract of Tagetes patula roots on blood pressure led to the isolation of well known citric (1) and malic acid (7) as hypotensive, and pyridine hydrochloride (4) as hypertensive constituents of the plant along with a new constituent, 2-hydroxy, 5-hydroxymethyl furan (9). Citric acid and malic acid caused 71% and 43% fall in Mean Arterial Blood Pressure (MABP) of rats at the doses of 15 mg/kg and 30 mg/kg respectively while pyridine hydrochloride produced 34% rise in the MABP of rats at the dose of 30 mg/kg. LD50 and LD100 of citric acid in mice have been determined as 545 mg/kg and 1000 mg/kg, respectively.

  13. [Relationships between cadmium accumulation and organic acids in leaves of Solanum nigrum L. as a cadmium-hyperaccumulator].

    PubMed

    Sun, Rui-lian; Zhou, Qi-xing; Wang, Xin

    2006-04-01

    The influence of different cadmium concentrations on the organic acid level in leaves of the Cd hyperaccumulator, Solanum nigrum L., in particular, the relationship of organic acids with Cd accumulation in S. nigrum was investigated based on the pot-culture experiment. The results showed that the Cd concentration in S. nigrum leaves exceeded 100 microg x g(-1), the threshold value used to define Cd-hyperaccumulators, and the bioaccumulation coefficient of cadmium in shoots of S. nigrum was higher than 1 when Cd concentration in soil was 25 microg x g(-1). The level of organic acids in leaves of S. nigrum had significant differences between the seedling stage and the mature stage. At the seedling stage, the sequence of organic acids in leaves of S. nigrum was acetic acid> tartaric acid> malic acid> citric acid. On the contrary, the accumulation of organic acids in S. nigrum at the mature stage was approximately in the following sequence malic acid> tartaric acid, acetic acid> citric acid. The significant positive correlation between Cd accumulation in leaves of S. nigrum and the concentration of tartaric acid in leaves of S. nigrum was observed at the seedling stage, whereas there was a significant positive correlation between Cd accumulation in leaves of S. nigrum and both acetic and citric acid concentrations at the mature stage. These results indicated that tartaric, acetic and citric acids in leaves of S. nigrum might act as the indication of Cd hyperaccumulation. PMID:16768003

  14. [Rapid determination of eight organic acids in plant tissue by sequential extraction and high performance liquid chromatography].

    PubMed

    Huang, Tianzhi; Wang, Shijie; Liu Xiuming; Liu, Hong; Wu, Yanyou; Luo Xuqiang

    2014-12-01

    A sequential extraction method was developed to determine different forms of oxalate and seven oxalate-metabolism-related organic acids (glyoxylic acid, tartaric acid, glycolic acid, malic acid, acetic acid, citric acid, succinic acid) in plant tissue. The ultra-pure water was used as the extraction medium to obtain water-soluble oxalic acid and the other seven water-soluble organic acids. After the extraction of the water-soluble organic acids, the residues were extracted by dilute hydrochloric acid successively to get the acid-soluble oxalate which entered the liquid phase. A Hypersil ODS column was used with 5 mmol/L potassium dihydrogen phosphate buffer solution (pH 2. 8) as the mobile phase. The diode array detector was set at 210 nm and the column temperature at 30 °C with the injection volume of 5 µL. The flow rate was controlled at different times which allowed a good and rapid separation of the organic acids and hydrochloric acid. Under these conditions, the linear ranges of the method were 1-2000 mg/L for oxalic acid, 25-2,000 mg/L for acetic acid, and 10-2,000 mg/L for glyoxylic acid, tartaric acid, glycolic acid, malic acid, citric acid and succinic acid, with the correlation coefficients of the eight organic acids ≥ 0. 9996. The average recoveries of the eight organic acids in leaves and roots were 93. 5%-104. 4% and 85. 3%-105. 4% with RSDs of 0. 15% -2.43% and 0. 31%-2. 9% (n=7), respectively. The limits of detection ranged from 1 to 10 ng (S/N=3). The results indicated that the method is accurate, rapid and reproducible for the determination of organic acids in plant samples.

  15. Analysis of Organic Acids, Deacetyl Asperulosidic Acid and Polyphenolic Compounds as a Potential Tool for Characterization of Noni (Morinda citrifolia) Products.

    PubMed

    Bittová, Miroslava; Hladůkova, Dita; Roblová, Vendula; Krácmar, Stanislav; Kubán, Petr; Kubán, Vlastimil

    2015-11-01

    Organic acids, deacetyl asperulosidic acid (DAA) and polyphenolic compounds in various noni (Morinda citrifolia L.) products (4 juices, 4 dry fruit powders and 2 capsules with dry fruit powder) were analyzed. Reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a variable wavelength detector (VWD) and electrospray ionization time-of-flight mass spectrometer (ESI-TOF MS) was applied for simultaneous analysis of organic acids (malic, lactic, citric and succinic acid) and DAA. An RP-HPLC method with diode-array detector (DAD) was developed for the analysis of polyphenolic compound content (rutin, catechin, quercitrin, kaempferol, gallic acid, caffeic acid and p-coumaric acid). The developed methods can contribute to better characterization of available noni products that is required from the consumers. In our study, we discovered significant dissimilarities in the content of DAA, citric acid and several phenolic compounds in some samples.

  16. Analysis of Organic Acids, Deacetyl Asperulosidic Acid and Polyphenolic Compounds as a Potential Tool for Characterization of Noni (Morinda citrifolia) Products.

    PubMed

    Bittová, Miroslava; Hladůkova, Dita; Roblová, Vendula; Krácmar, Stanislav; Kubán, Petr; Kubán, Vlastimil

    2015-11-01

    Organic acids, deacetyl asperulosidic acid (DAA) and polyphenolic compounds in various noni (Morinda citrifolia L.) products (4 juices, 4 dry fruit powders and 2 capsules with dry fruit powder) were analyzed. Reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a variable wavelength detector (VWD) and electrospray ionization time-of-flight mass spectrometer (ESI-TOF MS) was applied for simultaneous analysis of organic acids (malic, lactic, citric and succinic acid) and DAA. An RP-HPLC method with diode-array detector (DAD) was developed for the analysis of polyphenolic compound content (rutin, catechin, quercitrin, kaempferol, gallic acid, caffeic acid and p-coumaric acid). The developed methods can contribute to better characterization of available noni products that is required from the consumers. In our study, we discovered significant dissimilarities in the content of DAA, citric acid and several phenolic compounds in some samples. PMID:26749805

  17. Nucleic acid detection compositions

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James L.

    2008-08-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  18. Cleavage of nucleic acids

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    2000-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  19. Nucleic acid detection assays

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James E.

    2005-04-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  20. Cleavage of nucleic acids

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor L.; Brow, Mary Ann D.; Dahlberg, James E.

    2007-12-11

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  1. Cleavage of nucleic acids

    SciTech Connect

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow; Mary Ann D.; Dahlberg, James E.

    2010-11-09

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  2. Editorial: Acid precipitation

    SciTech Connect

    1995-09-01

    This editorial focuses on acid rain and the history of public and governmental response to acid rain. Comments on a book by Gwineth Howell `Acid Rain and Acid Waters` are included. The editor feels that Howells has provide a service to the environmental scientific community, with a textbook useful to a range of people, as well as a call for decision makers to learn from the acid rain issue and use it as a model for more sweeping global environmental issues. A balance is needed among several parameters such as level of evidence, probability that the evidence will lead to a specific direction and the cost to the global community. 1 tab.

  3. [Safety of folic acid].

    PubMed

    Ströhle, Alexander; Wolters, Maike; Hahn, Andreas

    2015-08-01

    Improving dietary folate intake is a central public health goal. However, critical voices have become louder warning of too high intake of folic acid. Safety concerns of a high folic acid exposure are usually limited to synthetic folic acid contained in drugs and food supplements. Against this background, the present article focuses on two matters: (a) How do the absorption and metabolism of synthetic folic acid differ from that of other folates? (b) How has the longterm safety of folic acid to be judged, especially regarding the risk of colorectal cancer, autism, asthma, impaired immune defence, masking vitamin B12 deficiency and interactions with the methotrexate metabolism?

  4. Amino acid analysis

    NASA Technical Reports Server (NTRS)

    Winitz, M.; Graff, J. (Inventor)

    1974-01-01

    The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.

  5. Acidic Ionic Liquids.

    PubMed

    Amarasekara, Ananda S

    2016-05-25

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

  6. Nucleic acid detection kits

    DOEpatents

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann; Kwiatkowski, Robert W.; Vavra, Stephanie H.

    2005-03-29

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of nucleic acid from various viruses in a sample.

  7. Acidic Ionic Liquids.

    PubMed

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition. PMID:27175515

  8. Influence of organic acids on rheological and bread-making characteristics of fortified wheat flour.

    PubMed

    Gupta, Sheetal; Shimray, Crassina A; Venkateswara Rao, G

    2012-06-01

    Flour was fortified with premix containing ferrous fumarate and folic acid. Organic acids such as citric acid, malic acid and tartaric acid, which are promoters of iron bioavailability, were added at three levels and their influence on rheological and bread-making characteristics was studied. Farinograph water absorption increased with fortificants, but with addition of organic acids there was a decrease. Maximum pressure was 77 mm in control, which increased to 78-88 mm with the addition of different acids to the fortified flour. Addition of organic acids to fortified flour brought about a decrease in peak viscosity, hot paste viscosity, cold paste viscosity and setback values. The L, a and b values of fortified breads were similar to that of control. Sensory analysis revealed marginal differences in the overall quality of breads prepared with fortified flour with the addition of organic acids.

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

    PubMed

    Reddy, K Ravi Charan; Kayastha, Arvind M

    2006-08-01

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

  10. Evaporation of a model skin lotion with beta-hydroxy acids.

    PubMed

    Al Bawab, A; Friberg, S E; Fusco, C

    2004-12-01

    Two beta-hydroxy acids, malic and salicylic acids were combined with a non-ionic surfactant, a commercial pentaoxyethylene sorbitan mono-oleate and water to form a simple model of a skin lotion and the phase diagrams were determined. One emulsion formulation with relative amounts of the three components similar to those in commercial lotions was used to observe microscopically the changes in the emulsion structure during evaporation. The microscope images were subsequently compared to the information from the phase diagram under equilibrium conditions. The results showed the behavior of the systems of the two acids to be distinctly different; as exemplified by that of a typical formulation with 3% by weight of acid and 5% of surfactant. The malic acid system consisted of vesicles, exclusively formed by the surfactant and water, in an aqueous molecular solution of the acid and the initial evaporation resulted in an increase of the acid concentration in the aqueous solution to reach 35.5%, before solid crystals of the acid solid solution appeared. The salicylic acid formulation, on the other hand, already at the beginning of the determination consisted of water, particles of the acid solid solution and surfactant vesicles. In both cases the remaining deposit after total evaporation was particles of a solid acid solution and liquid surfactant.

  11. Biotransformation of cinnamic acid, p-coumaric acid, caffeic acid, and ferulic acid by plant cell cultures of Eucalyptus perriniana.

    PubMed

    Katsuragi, Hisashi; Shimoda, Kei; Kubota, Naoji; Nakajima, Nobuyoshi; Hamada, Hatsuyuki; Hamada, Hiroki

    2010-01-01

    Biotransformations of phenylpropanoids such as cinnamic acid, p-coumaric acid, caffeic acid, and ferulic acid were investigated with plant-cultured cells of Eucalyptus perriniana. The plant-cultured cells of E. perriniana converted cinnamic acid into cinnamic acid β-D-glucopyranosyl ester, p-coumaric acid, and 4-O-β-D-glucopyranosylcoumaric acid. p-Coumaric acid was converted into 4-O-β-D-glucopyranosylcoumaric acid, p-coumaric acid β-D-glucopyranosyl ester, 4-O-β-D-glucopyranosylcoumaric acid β-D-glucopyranosyl ester, a new compound, caffeic acid, and 3-O-β-D-glucopyranosylcaffeic acid. On the other hand, incubation of caffeic acid with cultured E. perriniana cells gave 3-O-β-D-glucopyranosylcaffeic acid, 3-O-(6-O-β-D-glucopyranosyl)-β-D-glucopyranosylcaffeic acid, a new compound, 3-O-β-D-glucopyranosylcaffeic acid β-D-glucopyranosyl ester, 4-O-β-D-glucopyranosylcaffeic acid, 4-O-β-D-glucopyranosylcaffeic acid β-D-glucopyranosyl ester, ferulic acid, and 4-O-β-D-glucopyranosylferulic acid. 4-O-β-D-Glucopyranosylferulic acid, ferulic acid β-D-glucopyranosyl ester, and 4-O-β-D-glucopyranosylferulic acid β-D-glucopyranosyl ester were isolated from E. perriniana cells treated with ferulic acid.

  12. Process for the preparation of lactic acid and glyceric acid

    DOEpatents

    Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

    2008-12-02

    Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

  13. Well acidizing compositions and methods

    SciTech Connect

    Swanson, B. L.

    1980-12-23

    Gelled acidic compositions suitable for matrix acidizing or fracture acidizing of subterranean formations are provided comprising water, a water-dispersible polymeric viscosifier such as a polymer of acrylamide, an acid, and a polyphenolic material such as lignite.

  14. Bile acids but not acidic acids induce Barrett's esophagus.

    PubMed

    Sun, Dongfeng; Wang, Xiao; Gai, Zhibo; Song, Xiaoming; Jia, Xinyong; Tian, Hui

    2015-01-01

    Barrett's esophagus (BE) is associated with the development of esophageal adenocarcinoma (EAC). Bile acids (BAs) refluxing into the esophagus contribute to esophageal injury, which results in BE and subsequent EAC. We developed two animal models to test the role of BAs in the pathogenesis of BE. We surgically generated BA reflux, with or without gastric acid, in rats. In a second experiment, we fed animals separately with BAs and gastric acid. Pathologic changes were examined and the expression of Muc2 and Cdx2 in BE tissue was tested by immunostaining. Inflammatory factors in the plasma, as well as differentiation genes in BE were examined through highly sensitive ELISA and semi-quantitative RT-PCR techniques. We found that BAs are sufficient for the induction of esophagitis and Barrett's-like metaplasia in the esophagus. Overexpression of inflammatory cells, IL-6, and TNF-α was observed both in animals fed with BAs and surgically generated BA reflux. Furthermore, elevated levels of Cdx2, Muc2, Bmp4, Kit19, and Tff2 (differentiation genes in BE) were found in BA-treated rats. In conclusion, BAs, but not gastric acid, are a major causative factor for BE. We confirmed that BAs contribute to the development of BE by inducing the inflammatory response in the esophagus. Inhibiting BAs may be a promising therapy for BE.

  15. Microorganisms for producing organic acids

    DOEpatents

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  16. Acid-Base Homeostasis.

    PubMed

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

    2015-12-01

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

  17. Citric Acid Alternative to Nitric Acid Passivation

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L. (Compiler)

    2013-01-01

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

  18. Enzymatic gallic acid esterification.

    PubMed

    Weetal, H H

    1985-02-01

    Gallic acid esters of n-propyl and amyl alcohols have been produced by enzymatic synthesis in organic solvents using immobilized tannase. Studies indicate that maximum esterification of gallic acid occurs with amyl alcohol. The enzyme shows broad alcohol specificity. However, the enzyme exhibits absolute specificity for the acid portion of the ester. Studies were carried out on K(m), V(max), pH, and temperature optima.

  19. Amino acids and proteins.

    PubMed

    van Goudoever, Johannes B; Vlaardingerbroek, Hester; van den Akker, Chris H; de Groof, Femke; van der Schoor, Sophie R D

    2014-01-01

    Amino acids and protein are key factors for growth. The neonatal period requires the highest intake in life to meet the demands. Those demands include amino acids for growth, but proteins and amino acids also function as signalling molecules and function as neurotransmitters. Often the nutritional requirements are not met, resulting in a postnatal growth restriction. However, current knowledge on adequate levels of both amino acid as well as protein intake can avoid under nutrition in the direct postnatal phase, avoid the need for subsequent catch-up growth and improve later outcome.

  20. USGS Tracks Acid Rain

    USGS Publications Warehouse

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

    1995-01-01

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

  1. Recovery of organic acids

    DOEpatents

    Verser, Dan W.; Eggeman, Timothy J.

    2011-11-01

    A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

  2. Recovery of organic acids

    DOEpatents

    Verser, Dan W.; Eggeman, Timothy J.

    2009-10-13

    A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

  3. Characteristics of organic acids in the fruit of different pumpkin species.

    PubMed

    Nawirska-Olszańska, Agnieszka; Biesiada, Anita; Sokół-Łętowska, Anna; Kucharska, Alicja Z

    2014-04-01

    The aim of the research was to determine the composition of organic acids in fruit of different cultivars of three pumpkin species. The amount of acids immediately after fruit harvest and after 3 months of storage was compared. The content of organic acids in the examined pumpkin cultivars was assayed using the method of high performance liquid chromatography (HPLC). Three organic acids (citric acid, malic acid, and fumaric acid) were identified in the cultivars, whose content considerably varied depending on a cultivar. Three-month storage resulted in decreased content of the acids in the case of cultivars belonging to Cucurbita maxima and Cucurbita pepo species, while a slight increase was recorded for Cucurbita moschata species.

  4. Mutant fatty acid desaturase

    DOEpatents

    Shanklin, John; Cahoon, Edgar B.

    2004-02-03

    The present invention relates to a method for producing mutants of a fatty acid desaturase having a substantially increased activity towards fatty acid substrates with chains containing fewer than 18 carbons relative to an unmutagenized precursor desaturase having an 18 carbon atom chain length substrate specificity. The method involves inducing one or more mutations in the nucleic acid sequence encoding the precursor desaturase, transforming the mutated sequence into an unsaturated fatty acid auxotroph cell such as MH13 E. coli, culturing the cells in the absence of supplemental unsaturated fatty acids, thereby selecting for recipient cells which have received and which express a mutant fatty acid desaturase with an elevated specificity for fatty acid substrates having chain lengths of less than 18 carbon atoms. A variety of mutants having 16 or fewer carbon atom chain length substrate specificities are produced by this method. Mutant desaturases produced by this method can be introduced via expression vectors into prokaryotic and eukaryotic cells and can also be used in the production of transgenic plants which may be used to produce specific fatty acid products.

  5. Amino Acid Crossword Puzzle

    ERIC Educational Resources Information Center

    Sims, Paul A.

    2011-01-01

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

  6. Toxicology of Perfluoroalkyl acids

    EPA Science Inventory

    The Perfluoroalkyl acids(PFAAs) area a family of organic chemicals consisting of a perflurinated carbon backbone (4-12in length) and a acidic functional moiety (Carboxylate or sulfonate). These compounds have excellent surface-tension reducing properties and have numerous industr...

  7. Uric acid - blood

    MedlinePlus

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

  8. Bile acid transporters

    PubMed Central

    Dawson, Paul A.; Lan, Tian; Rao, Anuradha

    2009-01-01

    In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na+ taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OSTα-OSTβ. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers. PMID:19498215

  9. Analysis of Organic Acids.

    ERIC Educational Resources Information Center

    Griswold, John R.; Rauner, Richard A.

    1990-01-01

    Presented are the procedures and a discussion of the results for an experiment in which students select unknown carboxylic acids, determine their melting points, and investigate their solubility behavior in water and ethanol. A table of selected carboxylic acids is included. (CW)

  10. Omega-3 Fatty Acids

    MedlinePlus

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

  11. Toxicology of Perfluoroalkyl Acids*

    EPA Science Inventory

    The perfluoroalkyl acids (PFAAs) are a family of organic chemicals consisting of a perfluorinated carbon backbone (4-12 in length) and an acidic functional moiety (carboxylate or sulfonate). These compounds are chemically stable, have excellent surface-tension reducing properties...

  12. Salicylic Acid Topical

    MedlinePlus

    ... skin blemishes in people who have acne. Topical salicylic acid is also used to treat skin conditions that involve scaling or overgrowth of skin ... water for 15 minutes.Do not apply topical salicylic acid to skin that is broken, red, swollen, irritated, or infected. ...

  13. Efficient aspartic acid production by a psychrophile-based simple biocatalyst.

    PubMed

    Tajima, Takahisa; Hamada, Mai; Nakashimada, Yutaka; Kato, Junichi

    2015-10-01

    We previously constructed a Psychrophile-based Simple bioCatalyst (PSCat) reaction system, in which psychrophilic metabolic enzymes are inactivated by heat treatment, and used it here to study the conversion of aspartic acid from fumaric acid mediated by the activity of aspartate ammonia-lyase (aspartase). In Escherichia coli, the biosynthesis of aspartic acid competes with that of L-malic acid produced from fumaric acid by fumarase. In this study, E. coli aspartase was expressed in psychrophilic Shewanella livingstonensis Ac10 heat treated at 50 °C for 15 min. The resultant PSCat could convert fumaric acid to aspartic acid without the formation of L-malic acid because of heat inactivation of psychrophilic fumarase activity. Furthermore, alginate-immobilized PSCat produced high yields of aspartic acid and could be re-used nine times. The results of our study suggest that PSCat can be applied in biotechnological production as a new approach to increase the yield of target compounds. PMID:26254042

  14. Uric acid and hypertension.

    PubMed

    Feig, Daniel I

    2011-09-01

    A link between serum uric acid and the development of hypertension was first hypothesized in the 1870s. Although numerous epidemiologic studies in the 1980s and 1990s suggested an association, relatively little attention was paid to it until recently. Animal models have suggested a two-step pathogenesis by which uric acid initially activates the renin angiotensin system and suppresses nitric oxide, leading to uric acid-dependent increase in systemic vascular resistance, followed by a uric acid-mediated vasculopathy, involving renal afferent arterioles, resulting in a late sodium-sensitive hypertension. Initial clinical trials in young patients have supported these mechanisms in young patients but do not yet support pharmacologic reduction of serum uric acid as first-line therapy for hypertension.

  15. Biosynthesis of pulcherriminic acid

    PubMed Central

    MacDonald, J. C.

    1965-01-01

    1. Candida pulcherrima was grown on a complex medium to which various compounds had been added to determine their effect on the biosynthesis of pulcherriminic acid. Most of the pulcherriminic acid synthesized by C. pulcherrima PRL2019 was derived from the l-[1-14C]leucine added to the medium. 2. The cyclic dipeptide of l-leucine (cyclo-l-leucyl-l-leucyl) was shown, by trapping experiments involving cycloleucyl-leucyl isomers, to be synthesized by strain PRL2019. Cyclo-l-leucyl-l-leucyl was derived from l-leucine and was converted into pulcherriminic acid. Cyclo-l-leucyl-l-leucyl was a precursor of pulcherriminic acid in strain PRL2007 also. 3. The results supported the hypothesis that pulcherriminic acid is derived from l-leucine and that cyclo-l-leucyl-l-leucyl is an intermediate in the biosynthesis. PMID:5837792

  16. Total syntheses of cis-cyclopropane fatty acids: dihydromalvalic acid, dihydrosterculic acid, lactobacillic acid, and 9,10-methylenehexadecanoic acid.

    PubMed

    Shah, Sayali; White, Jonathan M; Williams, Spencer J

    2014-12-14

    cis-Cyclopropane fatty acids (cis-CFAs) are widespread constituents of the seed oils of subtropical plants, membrane components of bacteria and protozoa, and the fats and phospholipids of animals. We describe a systematic approach to the synthesis of enantiomeric pairs of four cis-CFAs: cis-9,10-methylenehexadecanoic acid, lactobacillic acid, dihydromalvalic acid, and dihydrosterculic acid. The approach commences with Rh2(OAc)4-catalyzed cyclopropenation of 1-octyne and 1-decyne, and hinges on the preparative scale chromatographic resolution of racemic 2-alkylcycloprop-2-ene-1-carboxylic acids using a homochiral Evan's auxiliary. Saturation of the individual diastereomeric N-cycloprop-2-ene-1-carbonylacyloxazolidines, followed by elaboration to alkylcyclopropylmethylsulfones, allowed Julia-Kocienski olefination with various ω-aldehyde-esters. Finally, saponification and diimide reduction afforded the individual cis-CFA enantiomers. PMID:25321346

  17. Metabolism of Sugars and Organic Acids in Immature Grape Berries

    PubMed Central

    Hardy, P. J.

    1968-01-01

    Individual intact excised immature Sultana berries were supplied through the cut pedicel with 14C-sugars and organic acids. When 14C-hexoses were supplied malic and tartaric acids accounted for 25% and 10% of the total activity extracted after 24 hours, and sucrose was synthesized. It is proposed that the changes in the levels of organic acids during ripening are related to changes in the ability of the berry to synthesize them. Although administration of uniformly labeled sucrose resulted in the unequal labeling of glucose and fructose, the results indicate breakdown of sucrose by invertase. It is suggested that the route of entry of the pedicel-fed sugars into the berry may be different from the route taken by sugar translocated from the leaf. PMID:16656755

  18. Effects of intermediate metabolite carboxylic acids of TCA cycle on Microcystis with overproduction of phycocyanin.

    PubMed

    Bai, Shijie; Dai, Jingcheng; Xia, Ming; Ruan, Jing; Wei, Hehong; Yu, Dianzhen; Li, Ronghui; Jing, Hongmei; Tian, Chunyuan; Song, Lirong; Qiu, Dongru

    2015-04-01

    Toxic Microcystis species are the main bloom-forming cyanobacteria in freshwaters. It is imperative to develop efficient techniques to control these notorious harmful algal blooms (HABs). Here, we present a simple, efficient, and environmentally safe algicidal way to control Microcystis blooms, by using intermediate carboxylic acids from the tricarboxylic acid (TCA) cycle. The citric acid, alpha-ketoglutaric acid, succinic acid, fumaric acid, and malic acid all exhibited strong algicidal effects, and particularly succinic acid could cause the rapid lysis of Microcystis in a few hours. It is revealed that the Microcystis-lysing activity of succinic acid and other carboxylic acids was due to their strong acidic activity. Interestingly, the acid-lysed Microcystis cells released large amounts of phycocyanin, about 27-fold higher than those of the control. On the other hand, the transcription of mcyA and mcyD of the microcystin biosynthesis operon was not upregulated by addition of alpha-ketoglutaric acid and other carboxylic acids. Consider the environmental safety of intermediate carboxylic acids. We propose that administration of TCA cycle organic acids may not only provide an algicidal method with high efficiency and environmental safety but also serve as an applicable way to produce and extract phycocyanin from cyanobacterial biomass.

  19. Gluconic acid production.

    PubMed

    Anastassiadis, Savas; Morgunov, Igor G

    2007-01-01

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

  20. Trans Fatty Acids

    NASA Astrophysics Data System (ADS)

    Doyle, Ellin

    1997-09-01

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

  1. Sulfuric Acid on Europa

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain.

    This image is based on data gathered by Galileo's near infrared mapping spectrometer.

    Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks.

    Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  2. Strongly Acidic Auxin Indole-3-Methanesulfonic Acid

    PubMed Central

    Cohen, Jerry D.; Baldi, Bruce G.; Bialek, Krystyna

    1985-01-01

    A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. In addition, the utility of both Fourier transform infrared spectrometry and fast atom bombardment mass spectrometry for analysis of IMS has been demonstrated. IMS was shown to be an active auxin, stimulating soybean hypocotyl elongation, bean first internode curvature, and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 micromolar concentration, IMS exhibited a basipetal polarity in its transport in both corn coleoptile and soybean hypocotyl sections. [14C]IMS should, therefore, be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles. PMID:16664007

  3. [Formation of organic acids by fungi isolated from the surface of stone monuments].

    PubMed

    Sazanova, K V; Shchiparev, S M; Vlasov, D Iu

    2014-01-01

    Capacity of the fungi isolated from the surface of stone monuments for acid formation was studied in cultures under various carbon sources and cultivation conditions. The composition of organic nutrients was adjusted according to the results of investigation of the surface layers from the monuments in urban environment. The primary soil formed at the surface of the stone monuments under urban conditions was shown to contain a variety of carbon and nitrogen sources and is a rich substrate for fungal growth. Oxalic acid was produced by fungi grown on media with various concentrations of sugars, sugar alcohols, and organic acids. Malic, citric, fumaric, and succinic acids were identified only at elevated carbohydrate concentrations, mostly in liquid cultures. Oxalic acid was the dominant among the acids produced by Aspergillus niger at all experimental setups. Unlike A. niger, the relative content of oxalic acid produced by Penicillium citrinum decreased at high carbohydrate concentrations. PMID:25844464

  4. [Formation of organic acids by fungi isolated from the surface of stone monuments].

    PubMed

    Sazanova, K V; Shchiparev, S M; Vlasov, D Iu

    2014-01-01

    Capacity of the fungi isolated from the surface of stone monuments for acid formation was studied in cultures under various carbon sources and cultivation conditions. The composition of organic nutrients was adjusted according to the results of investigation of the surface layers from the monuments in urban environment. The primary soil formed at the surface of the stone monuments under urban conditions was shown to contain a variety of carbon and nitrogen sources and is a rich substrate for fungal growth. Oxalic acid was produced by fungi grown on media with various concentrations of sugars, sugar alcohols, and organic acids. Malic, citric, fumaric, and succinic acids were identified only at elevated carbohydrate concentrations, mostly in liquid cultures. Oxalic acid was the dominant among the acids produced by Aspergillus niger at all experimental setups. Unlike A. niger, the relative content of oxalic acid produced by Penicillium citrinum decreased at high carbohydrate concentrations.

  5. Protein Crystal Malic Enzyme

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Malic Enzyme is a target protein for drug design because it is a key protein in the life cycle of intestinal parasites. After 2 years of effort on Earth, investigators were unable to produce any crystals that were of high enough quality and for this reason the structure of this important protein could not be determined. Crystals obtained from one STS-50 were of superior quality allowing the structure to be determined. This is just one example why access to space is so vital for these studies. Principal Investigator is Larry DeLucas.

  6. Understanding acid rain

    SciTech Connect

    Budiansky, S.

    1981-06-01

    The complexities of the phenomenon of acid rain are described. Many factors, including meteorology, geology, chemistry, and biology, all play parts. Varying weather, varying soils, the presence of other pollutants and species differences all act to blur the connections between industrial emissions, acid rain, and environmental damage. Some experts believe that the greatest pH shock to lakes occurs during snow melt and runoff in the spring; others believe that much of the plant damage ascribed to acid rain is actually due to the effects of ozone. Much work needs to be done in the area of sampling. Historical data are lacking and sampling methods are not sufficiently accurate. (JMT)

  7. Understanding Acid Base Disorders.

    PubMed

    Gomez, Hernando; Kellum, John A

    2015-10-01

    The concentration of hydrogen ions is regulated in biologic solutions. There are currently 3 recognized approaches to assess changes in acid base status. First is the traditional Henderson-Hasselbalch approach, also called the physiologic approach, which uses the relationship between HCO3(-) and Pco2; the second is the standard base excess approach based on the Van Slyke equation. The third approach is the quantitative or Stewart approach, which uses the strong ion difference and the total weak acids. This article explores the origins of the current concepts framing the existing methods to analyze acid base balance.

  8. Acid rain and soil.

    PubMed

    vanLoon, G W

    1984-08-01

    A summary of important chemical properties of soil is given and the way in which acid rain may affect these properties is discussed. Acid rain may suppress microbiological decomposition and nitrification processes, thus influencing the nutrient status of soils. It has also been found that soil organic matter is less soluble in more acid solutions. Changed nutrient availability patterns are predicted in a low pH environment and enhanced leaching of essential elements from the soil exchange complex has been observed. Increased solubility of potentially toxic elements such as aluminium may also occur from soils which have been exposed to acidified rainfall.

  9. Disorders of Amino Acid Metabolism

    MedlinePlus

    ... Aspiration Syndrome Additional Content Medical News Disorders of Amino Acid Metabolism By Lee M. Sanders, MD, MPH NOTE: ... Metabolic Disorders Disorders of Carbohydrate Metabolism Disorders of Amino Acid Metabolism Disorders of Lipid Metabolism Amino acids are ...

  10. Acetic acid in aged vinegar affects molecular targets for thrombus disease management.

    PubMed

    Jing, Li; Yanyan, Zhang; Junfeng, Fan

    2015-08-01

    To elucidate the mechanism underlying the action of dietary vinegar on antithrombotic activity, acetic acid, the main acidic component of dietary vinegar, was used to determine antiplatelet and fibrinolytic activity. The results revealed that acetic acid significantly inhibits adenosine diphosphate (ADP)-, collagen-, thrombin-, and arachidonic acid (AA)-induced platelet aggregation. Acetic acid (2.00 mM) reduced AA-induced platelet aggregation to approximately 36.82 ± 1.31%, and vinegar (0.12 mL L(-1)) reduced the platelet aggregation induced by AA to 30.25 ± 1.34%. Further studies revealed that acetic acid exerts its effects by inhibiting cyclooxygenase-1 and the formation of thromboxane-A2. Organic acids including acetic acid, formic acid, lactic acid, citric acid, and malic acid also showed fibrinolytic activity; specifically, the fibrinolytic activity of acetic acid amounted to 1.866 IU urokinase per mL. Acetic acid exerted its fibrinolytic activity by activating plasminogen during fibrin crossing, thus leading to crosslinked fibrin degradation by the activated plasmin. These results suggest that organic acids in dietary vinegar play important roles in the prevention and cure of cardiovascular diseases.

  11. [Determination of organic acids in rice wine by ion-exclusion chromatography].

    PubMed

    Lin, Xiaojie; Wei, Wei; He, Zhigang; Lin, Xiaozi

    2014-03-01

    An ion-exclusion chromatographic method for the simultaneous determination of organic acids in rice wine was developed. An IC-Pak Ion Exclusion column (300 mm x 7.8 mm, 7 microm) was used at 50 degrees C. The mobile phases were H2SO4 (phase A) and acetonitrile (phase B) (98:2, v/v) at a flow rate of 0.5 mL/min. The gradient elution program was as follows: 0-40 min, 0.01 mol/L H2SO4 to 0.02 mol/L H2SO4; 40-50 min, 0.01 mol/L H2SO4. The injection volume was 10 microL. The detection wavelength was set at 210 nm. The results showed that oxalic acid, maleic acid, citric acid, tartaric acid, malic acid, ascorbic acid, succinic acid, lactic, fumaric acid, acetic acid, propionic acid, isobutyric acid and butyric acid were completely separated and determined in 30 min. The linear correlation coefficients were above 0.999 7 in the range of 0.001- 1.000 g/L. Under the optimized conditions, the recoveries of organic acids in rice wine were in the range of 93.4% - 103.8% with the relative standard deviations (RSDs, n = 5) of 0.1% - 1.5%. This method is feasible, convenient, fast, accurate and applicable for the quantitative analysis of the organic acids in rice wine.

  12. [Determination of organic acids in rice wine by ion-exclusion chromatography].

    PubMed

    Lin, Xiaojie; Wei, Wei; He, Zhigang; Lin, Xiaozi

    2014-03-01

    An ion-exclusion chromatographic method for the simultaneous determination of organic acids in rice wine was developed. An IC-Pak Ion Exclusion column (300 mm x 7.8 mm, 7 microm) was used at 50 degrees C. The mobile phases were H2SO4 (phase A) and acetonitrile (phase B) (98:2, v/v) at a flow rate of 0.5 mL/min. The gradient elution program was as follows: 0-40 min, 0.01 mol/L H2SO4 to 0.02 mol/L H2SO4; 40-50 min, 0.01 mol/L H2SO4. The injection volume was 10 microL. The detection wavelength was set at 210 nm. The results showed that oxalic acid, maleic acid, citric acid, tartaric acid, malic acid, ascorbic acid, succinic acid, lactic, fumaric acid, acetic acid, propionic acid, isobutyric acid and butyric acid were completely separated and determined in 30 min. The linear correlation coefficients were above 0.999 7 in the range of 0.001- 1.000 g/L. Under the optimized conditions, the recoveries of organic acids in rice wine were in the range of 93.4% - 103.8% with the relative standard deviations (RSDs, n = 5) of 0.1% - 1.5%. This method is feasible, convenient, fast, accurate and applicable for the quantitative analysis of the organic acids in rice wine. PMID:24984473

  13. Effect of low-molecular-weight organic acids on photo-degradation of phenanthrene catalyzed by Fe(III)-smectite under visible light.

    PubMed

    Jia, Hanzhong; Chen, Hongxia; Nulaji, Gulimire; Li, Xiyou; Wang, Chuanyi

    2015-11-01

    The photolysis of polycyclic aromatic hydrocarbons (PAHs) is potentially an important process for its transformation and fate on contaminated soil surfaces. In this study, phenanthrene is employed as a model to explore PAH photodegradation with the assistance of Fe(III)-smectite under visible-light while focusing on roles played by five low-molecular-weight organic acids (LMWOAs), i.e., malic acid, oxalic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), and nitrilotriacetic acid. Our results show that oxalic acid is most effective in promoting the photodegradation of phenanthrene, while only a slight increase in the rate of phenanthrene photodegradation is observed in the presence of malic acid. Electron paramagnetic resonance experiments confirm the formation of CO2(-) radicals in the presence of malic and oxalic acid, which provides strong evidence for generating OH and subsequent photoreaction pathways. The presence of EDTA or nitrilotriacetic acid significantly inhibits both Fe(II) formation and phenanthrene photodegradation because these organic anions tend to chelate with Fe(III), leading to decreases in the electron-accepting potential of Fe(III)-smectite and a weakened interaction between phenanthrene and Fe(III)-smectite. These observations provide valuable insights into the transformation and fate of PAHs in the natural soil environment and demonstrate the potential for using some LMWOAs as additives for the remediation of contaminated soil. PMID:26091867

  14. Effect of low-molecular-weight organic acids on photo-degradation of phenanthrene catalyzed by Fe(III)-smectite under visible light.

    PubMed

    Jia, Hanzhong; Chen, Hongxia; Nulaji, Gulimire; Li, Xiyou; Wang, Chuanyi

    2015-11-01

    The photolysis of polycyclic aromatic hydrocarbons (PAHs) is potentially an important process for its transformation and fate on contaminated soil surfaces. In this study, phenanthrene is employed as a model to explore PAH photodegradation with the assistance of Fe(III)-smectite under visible-light while focusing on roles played by five low-molecular-weight organic acids (LMWOAs), i.e., malic acid, oxalic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), and nitrilotriacetic acid. Our results show that oxalic acid is most effective in promoting the photodegradation of phenanthrene, while only a slight increase in the rate of phenanthrene photodegradation is observed in the presence of malic acid. Electron paramagnetic resonance experiments confirm the formation of CO2(-) radicals in the presence of malic and oxalic acid, which provides strong evidence for generating OH and subsequent photoreaction pathways. The presence of EDTA or nitrilotriacetic acid significantly inhibits both Fe(II) formation and phenanthrene photodegradation because these organic anions tend to chelate with Fe(III), leading to decreases in the electron-accepting potential of Fe(III)-smectite and a weakened interaction between phenanthrene and Fe(III)-smectite. These observations provide valuable insights into the transformation and fate of PAHs in the natural soil environment and demonstrate the potential for using some LMWOAs as additives for the remediation of contaminated soil.

  15. Pantothenic acid and biotin

    MedlinePlus

    ... well as other nutrients, are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board ... level that is thought to ensure enough nutrition. Dietary Reference Intakes for pantothenic acid: Age 0 to 6 months: ...

  16. Amino Acid Metabolism Disorders

    MedlinePlus

    Metabolism is the process your body uses to make energy from the food you eat. Food is ... One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup ...

  17. [Hydrofluoric acid burns].

    PubMed

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

    2016-01-01

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

  18. Folic acid - test

    MedlinePlus

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

  19. Nitric acid poisoning

    MedlinePlus

    Symptoms from swallowing nitric acid may include: Abdominal pain - severe Burns to skin or mouth Drooling Fever Mouth pain - severe Rapid drop in blood pressure (shock) Throat swelling, which leads to breathing difficulty ...

  20. [Hydrofluoric acid burns].

    PubMed

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

    2016-01-01

    Hydrofluoric acid is increasingly used as a rust remover and detergent. Dermal contact with hydrofluoric acid results in a chemical burn characterized by severe pain and deep tissue necrosis. It may cause electrolyte imbalances with lethal consequences. It is important to identify high-risk patients. 'High risk' is defined as a total affected body area > 3% or exposure to hydrofluoric acid in a concentration > 50%. We present the cases of three male patients (26, 31, and 39 years old) with hydrofluoric acid burns of varying severity and describe the subsequent treatments. The application of calcium gluconate 2.5% gel to the skin is the cornerstone of the treatment, reducing pain as well as improving wound healing. Nails should be thoroughly inspected and possibly removed if the nail is involved, to ensure proper healing. In high-risk patients, plasma calcium levels should be evaluated and cardiac monitoring is indicated. PMID:27189091

  1. Difficult Decisions: Acid Rain.

    ERIC Educational Resources Information Center

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

    Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

  2. Hyaluronic acid fillers.

    PubMed

    Monheit, Gary D; Coleman, Kyle M

    2006-01-01

    Although hyaluronic acids are a relatively new treatment for facial lines and wrinkles, they have provided numerous advances in the area of cosmetic surgery. This article discusses the inherent properties of hyaluronic acid fillers that make them ideal for treatment of facial lines. It encompasses a review of the current literature on U.S. Food and Drug Administration-approved hyaluronic acid fillers and the role that each of these fillers currently has in facial cosmetics. This article also discusses the potential pitfalls and adverse effects that can be associated with using hyaluronic acids for filling facial lines. Finally, it serves as an overview of current techniques for clinical assessment of patients as well as administration and treatment of facial lines and wrinkles.

  3. Boric acid poisoning

    MedlinePlus

    Borax poisoning ... The main symptoms of boric acid poisoning are blue-green vomit, diarrhea, and a bright red rash on the skin. Other symptoms may include: Blisters Collapse Coma Convulsions Drowsiness ...

  4. Stomach acid test

    MedlinePlus

    Gastric acid secretion test ... The test is done after you have not eaten for a while so fluid is all that remains in ... injected into your body. This is done to test the ability of the cells in the stomach ...

  5. Aminolevulinic Acid Topical

    MedlinePlus

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

  6. Amino Acids and Chirality

    NASA Technical Reports Server (NTRS)

    Cook, Jamie E.

    2012-01-01

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

  7. (Acid rain workshop)

    SciTech Connect

    Turner, R.S.

    1990-12-05

    The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment Program, the United Nations Economic and Social Commission for Asia and the Pacific, and the World Bank. Papers presented on the first day discussed how the experience gained with acid rain in North America and Europe might be applied to the Asian situation. Papers describing energy use projections, sulfur emissions, and effects of acid rain in several Asian countries were presented on the second day. The remaining time was allotted to discussion, planning, and writing plans for a future research program.

  8. Folic acid in diet

    MedlinePlus

    ... a regular supply of the vitamin in the foods you eat. ... vitamins have been added to the food. Many foods are now fortified with folic acid. Some of these are enriched breads, cereals, flours, ...

  9. Valproic Acid and Pregnancy

    MedlinePlus

    ... in the treatment of epilepsy, and to treat bipolar disorder and migraines. I have been taking valproic acid ... that women with seizure disorders and women with bipolar disorder might have menstrual problems and difficulty getting pregnant. ...

  10. Citric acid urine test

    MedlinePlus

    ... The test is used to diagnose renal tubular acidosis and evaluate kidney stone disease. Normal Results The ... level of citric acid may mean renal tubular acidosis and a tendency to form calcium kidney stones. ...

  11. Folic Acid Quiz

    MedlinePlus

    ... more easily than natural food folate. Close × Answer: D CORRECT: Folic acid reduces the risk for spina ... g., orange juice and green vegetables). Close × Answer: D CORRECT: Spina bifida and anencephaly are neural tube ...

  12. Hydrofluoric acid poisoning

    MedlinePlus

    ... your skin or eyes, you may have: Blisters Burns Pain Vision loss Hydrofluoric acid poisoning can have ... urine tests Camera down the throat to see burns in the esophagus and the stomach (endoscopy) Fluids ...

  13. Association Mapping of Main Tomato Fruit Sugars and Organic Acids

    PubMed Central

    Zhao, Jiantao; Xu, Yao; Ding, Qin; Huang, Xinli; Zhang, Yating; Zou, Zhirong; Li, Mingjun; Cui, Lu; Zhang, Jing

    2016-01-01

    Association mapping has been widely used to map the significant associated loci responsible for natural variation in complex traits and are valuable for crop improvement. Sugars and organic acids are the most important metabolites in tomato fruits. We used a collection of 174 tomato accessions composed of Solanum lycopersicum (123 accessions) and S. lycopersicum var cerasiforme (51 accessions) to detect significantly associated loci controlling the variation of main sugars and organic acids. The accessions were genotyped with 182 SSRs spreading over the tomato genome. Association mapping was conducted on the main sugars and organic acids detected by gas chromatography-mass spectrometer (GC-MS) over 2 years using the mixed linear model (MLM). We detected a total of 58 significantly associated loci (P < 0.001) for the 17 sugars and organic acids, including fructose, glucose, sucrose, citric acid, malic acid. These results not only co-localized with several reported QTLs, including fru9.1/PV, suc9.1/PV, ca2.1/HS, ca3.1/PV, ca4.1/PV, and ca8.1/PV, but also provided a list of candidate significantly associated loci to be functionally validated. These significantly associated loci could be used for deciphering the genetic architecture of tomato fruit sugars and organic acids and for tomato quality breeding. PMID:27617019

  14. Association Mapping of Main Tomato Fruit Sugars and Organic Acids.

    PubMed

    Zhao, Jiantao; Xu, Yao; Ding, Qin; Huang, Xinli; Zhang, Yating; Zou, Zhirong; Li, Mingjun; Cui, Lu; Zhang, Jing

    2016-01-01

    Association mapping has been widely used to map the significant associated loci responsible for natural variation in complex traits and are valuable for crop improvement. Sugars and organic acids are the most important metabolites in tomato fruits. We used a collection of 174 tomato accessions composed of Solanum lycopersicum (123 accessions) and S. lycopersicum var cerasiforme (51 accessions) to detect significantly associated loci controlling the variation of main sugars and organic acids. The accessions were genotyped with 182 SSRs spreading over the tomato genome. Association mapping was conducted on the main sugars and organic acids detected by gas chromatography-mass spectrometer (GC-MS) over 2 years using the mixed linear model (MLM). We detected a total of 58 significantly associated loci (P < 0.001) for the 17 sugars and organic acids, including fructose, glucose, sucrose, citric acid, malic acid. These results not only co-localized with several reported QTLs, including fru9.1/PV, suc9.1/PV, ca2.1/HS, ca3.1/PV, ca4.1/PV, and ca8.1/PV, but also provided a list of candidate significantly associated loci to be functionally validated. These significantly associated loci could be used for deciphering the genetic architecture of tomato fruit sugars and organic acids and for tomato quality breeding.

  15. Metabolic engineering of biocatalysts for carboxylic acids production

    PubMed Central

    Liu, Ping; Jarboe, Laura R.

    2012-01-01

    Fermentation of renewable feedstocks by microbes to produce sustainable fuels and chemicals has the potential to replace petrochemical-based production. For example, carboxylic acids produced by microbial fermentation can be used to generate primary building blocks of industrial chemicals by either enzymatic or chemical catalysis. In order to achieve the titer, yield and productivity values required for economically viable processes, the carboxylic acid-producing microbes need to be robust and well-performing. Traditional strain development methods based on mutagenesis have proven useful in the selection of desirable microbial behavior, such as robustness and carboxylic acid production. On the other hand, rationally-based metabolic engineering, like genetic manipulation for pathway design, has becoming increasingly important to this field and has been used for the production of several organic acids, such as succinic acid, malic acid and lactic acid. This review investigates recent works on Saccharomyces cerevisiae and Escherichia coli, as well as the strategies to improve tolerance towards these chemicals. PMID:24688671

  16. Association Mapping of Main Tomato Fruit Sugars and Organic Acids.

    PubMed

    Zhao, Jiantao; Xu, Yao; Ding, Qin; Huang, Xinli; Zhang, Yating; Zou, Zhirong; Li, Mingjun; Cui, Lu; Zhang, Jing

    2016-01-01

    Association mapping has been widely used to map the significant associated loci responsible for natural variation in complex traits and are valuable for crop improvement. Sugars and organic acids are the most important metabolites in tomato fruits. We used a collection of 174 tomato accessions composed of Solanum lycopersicum (123 accessions) and S. lycopersicum var cerasiforme (51 accessions) to detect significantly associated loci controlling the variation of main sugars and organic acids. The accessions were genotyped with 182 SSRs spreading over the tomato genome. Association mapping was conducted on the main sugars and organic acids detected by gas chromatography-mass spectrometer (GC-MS) over 2 years using the mixed linear model (MLM). We detected a total of 58 significantly associated loci (P < 0.001) for the 17 sugars and organic acids, including fructose, glucose, sucrose, citric acid, malic acid. These results not only co-localized with several reported QTLs, including fru9.1/PV, suc9.1/PV, ca2.1/HS, ca3.1/PV, ca4.1/PV, and ca8.1/PV, but also provided a list of candidate significantly associated loci to be functionally validated. These significantly associated loci could be used for deciphering the genetic architecture of tomato fruit sugars and organic acids and for tomato quality breeding. PMID:27617019

  17. Association Mapping of Main Tomato Fruit Sugars and Organic Acids

    PubMed Central

    Zhao, Jiantao; Xu, Yao; Ding, Qin; Huang, Xinli; Zhang, Yating; Zou, Zhirong; Li, Mingjun; Cui, Lu; Zhang, Jing

    2016-01-01

    Association mapping has been widely used to map the significant associated loci responsible for natural variation in complex traits and are valuable for crop improvement. Sugars and organic acids are the most important metabolites in tomato fruits. We used a collection of 174 tomato accessions composed of Solanum lycopersicum (123 accessions) and S. lycopersicum var cerasiforme (51 accessions) to detect significantly associated loci controlling the variation of main sugars and organic acids. The accessions were genotyped with 182 SSRs spreading over the tomato genome. Association mapping was conducted on the main sugars and organic acids detected by gas chromatography-mass spectrometer (GC-MS) over 2 years using the mixed linear model (MLM). We detected a total of 58 significantly associated loci (P < 0.001) for the 17 sugars and organic acids, including fructose, glucose, sucrose, citric acid, malic acid. These results not only co-localized with several reported QTLs, including fru9.1/PV, suc9.1/PV, ca2.1/HS, ca3.1/PV, ca4.1/PV, and ca8.1/PV, but also provided a list of candidate significantly associated loci to be functionally validated. These significantly associated loci could be used for deciphering the genetic architecture of tomato fruit sugars and organic acids and for tomato quality breeding.

  18. Effects of genotype, latitude, and weather conditions on the composition of sugars, sugar alcohols, fruit acids, and ascorbic acid in sea buckthorn (Hippophaë rhamnoides ssp. mongolica) berry juice.

    PubMed

    Zheng, Jie; Yang, Baoru; Trépanier, Martin; Kallio, Heikki

    2012-03-28

    Sea buckthorn berries (Hippophaë rhamnoides ssp. mongolica) of nine varieties were collected from three growth locations in five inconsecutive years (n = 152) to study the compositional differences of sugars, sugar alcohols, fruit acids, and ascorbic acid in berries of different genotypes. Fructose and glucose (major sugars) were highest in Chuiskaya and Vitaminaya among the varieties studied, respectively. Malic acid and quinic acid (major acids) were highest in Pertsik and Vitaminaya, respectively. Ascorbic acid was highest in Oranzhevaya and lowest in Vitaminaya. Berry samples of nine varieties collected from two growth locations in five years (n = 124) were combined to study the effects of latitude and weather conditions on the composition of H. rhamnoides ssp. mongolica. Sea buckthorn berries grown at lower latitude had higher levels of total sugar and sugar/acid ratio and a lower level of total acid and were supposed to have better sensory properties than those grown at higher latitude. Glucose, quinic acid, and ascorbic acid were hardly influenced by weather conditions. The other components showed various correlations with temperature, radiation, precipitation, and humidity variables. In addition, fructose, sucrose, and myo-inositol correlated positively with each other and showed negative correlation with malic acid on the basis of all the samples studied (n = 152).

  19. Portable nucleic acid thermocyclers.

    PubMed

    Almassian, David R; Cockrell, Lisa M; Nelson, William M

    2013-11-21

    A nucleic acid thermal cycler is considered to be portable if it is under ten pounds, easily carried by one individual, and battery powered. Nucleic acid amplification includes both polymerase chain reaction (e.g. PCR, RT-PCR) and isothermal amplification (e.g. RPA, HDA, LAMP, NASBA, RCA, ICAN, SMART, SDA). There are valuable applications for portable nucleic acid thermocyclers in fields that include clinical diagnostics, biothreat detection, and veterinary testing. A system that is portable allows for the distributed detection of targets at the point of care and a reduction of the time from sample to answer. The designer of a portable nucleic acid thermocycler must carefully consider both thermal control and the detection of amplification. In addition to thermal control and detection, the designer may consider the integration of a sample preparation subsystem with the nucleic acid thermocycler. There are a variety of technologies that can achieve accurate thermal control and the detection of nucleic acid amplification. Important evaluation criteria for each technology include maturity, power requirements, cost, sensitivity, speed, and manufacturability. Ultimately the needs of a particular market will lead to user requirements that drive the decision between available technologies.

  20. Neutron Nucleic Acid Crystallography.

    PubMed

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination. PMID:26227050

  1. Neutron Nucleic Acid Crystallography.

    PubMed

    Chatake, Toshiyuki

    2016-01-01

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

  2. Utilization of acid tars

    SciTech Connect

    Frolov, A.F.; Denisova, T.L.; Aminov, A.N.

    1987-01-01

    Freshly produced acid tar (FPAT), obtained as refinery waste in treating petroleum oils with sulfuric acid and oleum, contains 80% or more sulfuric acid. Of such tars, pond acid tars, which contain up to 80% neutral petroleum products and sulfonated resins, are more stable, and have found applications in the production of binders for paving materials. In this article the authors are presenting results obtained in a study of the composition and reactivity of FPAT and its stability in storage in blends with asphalts obtained in deasphalting operations, and the possibility of using the FPAT in road construction has been examined. In this work, wastes were used which were obtained in treating the oils T-750, KhF-12, I-8A, and MS-14. Data on the change in group chemical composition of FPAT are shown, and the acidity, viscosity, needle penetration, and softening point of acid tars obtained from different grades of oils are plotted as functions of the storage time. It is also shown that the fresh and hardened FPATs differ in their solubilities in various solvents.

  3. Method for isolating nucleic acids

    SciTech Connect

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  4. Acidification and Acid Rain

    NASA Astrophysics Data System (ADS)

    Norton, S. A.; Veselã½, J.

    2003-12-01

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

  5. Identification of Catechin, Syringic Acid, and Procyanidin B2 in Wine as Stimulants of Gastric Acid Secretion.

    PubMed

    Liszt, Kathrin Ingrid; Eder, Reinhard; Wendelin, Sylvia; Somoza, Veronika

    2015-09-01

    Organic acids of wine, in addition to ethanol, have been identified as stimulants of gastric acid secretion. This study characterized the influence of other wine compounds, particularly phenolic compounds, on proton secretion. Forty wine parameters were determined in four red wines and six white wines, including the contents of organic acids and phenolic compounds. The secretory activity of the wines was determined in a gastric cell culture model (HGT-1 cells) by means of a pH-sensitive fluorescent dye. Red wines stimulated proton secretion more than white wines. Lactic acid and the phenolic compounds syringic acid, catechin, and procyanidin B2 stimulated proton secretion and correlated with the pro-secretory effect of the wines. Addition of the phenolic compounds to the least active white wine sample enhanced its proton secretory effect by 65 ± 21% (p < 0.05). These results indicate that not only malic and lactic acid but also bitter and astringent tasting phenolic compounds in wine contribute to its stimulatory effect on gastric acid secretion.

  6. Diurnal variations in leaf fluorescence induction kinetics: variable fluorescence in crassulacean Acid metabolism plants.

    PubMed

    Everson, G; Chen, S S; Black, C C

    1983-06-01

    The variable fluorescence of leaves from Kalanchoë daigremontiana and pineapple, Ananas comosus, both CAM plants, was found to change over a 24-hour cycle and to exhibit high temperature-dependent maxima during the night period. The time course of the induced fluorescence was correlated with malic acid accumulation but not with other aspects of CAM such as with the nature of the decarboxylation pathway or with stomatal movements. The variable fluorescences of sunflower (Helianthus annuus L.) and corn (Zea mays L.) leaves were compared with the CAM plants diurnally; both plants also exhibit high fluorescence maxima during the night period. We conclude that the assembly of the photosystems in the light is a primary process in photosynthesis induction and may be influenced by other cellular metabolic processes, specifically in the case of CAM leaves by malic acid accumulation. PMID:16663024

  7. Discovery of essential fatty acids

    PubMed Central

    Spector, Arthur A.; Kim, Hee-Yong

    2015-01-01

    Dietary fat was recognized as a good source of energy and fat-soluble vitamins by the first part of the 20th century, but fatty acids were not considered to be essential nutrients because they could be synthesized from dietary carbohydrate. This well-established view was challenged in 1929 by George and Mildred Burr who reported that dietary fatty acid was required to prevent a deficiency disease that occurred in rats fed a fat-free diet. They concluded that fatty acids were essential nutrients and showed that linoleic acid prevented the disease and is an essential fatty acid. The Burrs surmised that other unsaturated fatty acids were essential and subsequently demonstrated that linolenic acid, the omega-3 fatty acid analog of linoleic acid, is also an essential fatty acid. The discovery of essential fatty acids was a paradigm-changing finding, and it is now considered to be one of the landmark discoveries in lipid research. PMID:25339684

  8. Boric acid catalyzed chemoselective esterification of alpha-hydroxycarboxylic acids.

    PubMed

    Houston, Todd A; Wilkinson, Brendan L; Blanchfield, Joanne T

    2004-03-01

    Boric acid catalyzes the selective esterification of alpha-hydroxycarboxylic acids without causing significant esterification to occur with other carboxylic acids. The procedure is simple, high-yielding, and applicable to the esterification of alpha-hydroxy carboxylates in the presence of other carboxylic acids including beta-hydroxyacids within the same molecule. [reaction: see text

  9. Acid Rain, pH & Acidity: A Common Misinterpretation.

    ERIC Educational Resources Information Center

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  10. Ion-exclusion chromatography determination of organic acid in uridine 5'-monophosphate fermentation broth.

    PubMed

    Niu, Huanqing; Chen, Yong; Xie, Jingjing; Chen, Xiaochun; Bai, Jianxin; Wu, Jinglan; Liu, Dong; Ying, Hanjie

    2012-09-01

    Simultaneous determination of organic acids using ion-exclusion liquid chromatography and ultraviolet detection is described. The chromatographic conditions are optimized when an Aminex HPX-87H column (300 × 7.8 mm) is employed, with a solution of 3 mmol/L sulfuric acid as eluent, a flow rate of 0.4 mL/min and a column temperature of 60°C. Eight organic acids (including orotic acid, α-ketoglutaric acid, citric acid, pyruvic acid, malic acid, succinic acid, lactic acid and acetic acid) and one nucleotide are successfully quantified. The calibration curves for these analytes are linear, with correlation coefficients exceeding 0.999. The average recovery of organic acids is in the range of 97.6% ∼ 103.1%, and the relative standard deviation is in the range of 0.037% ∼ 0.38%. The method is subsequently applied to obtain organic acid profiles of uridine 5'-monophosphate culture broth fermented from orotic acid by Saccharomyces cerevisiae. These data demonstrate the quantitative accuracy for nucleotide fermentation mixtures, and suggest that the method may also be applicable to other biological samples. PMID:22634191

  11. Draft Genome Sequence of Ustilago trichophora RK089, a Promising Malic Acid Producer.

    PubMed

    Zambanini, Thiemo; Buescher, Joerg M; Meurer, Guido; Wierckx, Nick; Blank, Lars M

    2016-01-01

    The basidiomycetous smut fungus Ustilago trichophora RK089 produces malate from glycerol. De novo genome sequencing revealed a 20.7-Mbp genome (301 gap-closed contigs, 246 scaffolds). A comparison to the genome of Ustilago maydis 521 revealed all essential genes for malate production from glycerol contributing to metabolic engineering for improving malate production. PMID:27469969

  12. Draft Genome Sequence of Ustilago trichophora RK089, a Promising Malic Acid Producer

    PubMed Central

    Zambanini, Thiemo; Buescher, Joerg M.; Meurer, Guido; Blank, Lars M.

    2016-01-01

    The basidiomycetous smut fungus Ustilago trichophora RK089 produces malate from glycerol. De novo genome sequencing revealed a 20.7-Mbp genome (301 gap-closed contigs, 246 scaffolds). A comparison to the genome of Ustilago maydis 521 revealed all essential genes for malate production from glycerol contributing to metabolic engineering for improving malate production. PMID:27469969

  13. Aspartic acid in the hippocampus: a biomarker for postoperative cognitive dysfunction.

    PubMed

    Hu, Rong; Huang, Dong; Tong, Jianbin; Liao, Qin; Hu, Zhonghua; Ouyang, Wen

    2014-01-15

    This study established an aged rat model of cognitive dysfunction using anesthesia with 2% isoflurane and 80% oxygen for 2 hours. Twenty-four hours later, Y-maze test results showed that isoflurane significantly impaired cognitive function in aged rats. Gas chromatography-mass spectrometry results showed that isoflurane also significantly increased the levels of N,N-diethylacetamide, n-ethylacetamide, aspartic acid, malic acid and arabinonic acid in the hippocampus of isoflurane-treated rats. Moreover, aspartic acid, N,N-diethylacetamide, n-ethylacetamide and malic acid concentration was positively correlated with the degree of cognitive dysfunction in the isoflurane-treated rats. It is evident that hippocampal metabolite changes are involved in the formation of cognitive dysfunction after isoflurane anesthesia. To further verify these results, this study cultured hippocampal neurons in vitro, which were then treated with aspartic acid (100 μmol/L). Results suggested that aspartic acid concentration in the hippocampus may be a biomarker for predicting the occurrence and disease progress of cognitive dysfunction.

  14. Aspartic acid in the hippocampus: a biomarker for postoperative cognitive dysfunction

    PubMed Central

    Hu, Rong; Huang, Dong; Tong, Jianbin; Liao, Qin; Hu, Zhonghua; Ouyang, Wen

    2014-01-01

    This study established an aged rat model of cognitive dysfunction using anesthesia with 2% isoflurane and 80% oxygen for 2 hours. Twenty-four hours later, Y-maze test results showed that isoflurane significantly impaired cognitive function in aged rats. Gas chromatography-mass spectrometry results showed that isoflurane also significantly increased the levels of N,N-diethylacetamide, n-ethylacetamide, aspartic acid, malic acid and arabinonic acid in the hippocampus of isoflurane-treated rats. Moreover, aspartic acid, N,N-diethylacetamide, n-ethylacetamide and malic acid concentration was positively correlated with the degree of cognitive dysfunction in the isoflurane-treated rats. It is evident that hippocampal metabolite changes are involved in the formation of cognitive dysfunction after isoflurane anesthesia. To further verify these results, this study cultured hippocampal neurons in vitro, which were then treated with aspartic acid (100 μmol/L). Results suggested that aspartic acid concentration in the hippocampus may be a biomarker for predicting the occurrence and disease progress of cognitive dysfunction. PMID:25206795

  15. [Effect of organic acids on the biosynthesis of macrotetralide antibiotics by an Actinomyces chrysomallus var. carotenoides strain].

    PubMed

    Nefelova, M V; Sverdlova, A N; Silaev, A B

    1978-07-01

    The biosynthesis of macrotetrolides by Actinomyces chrysomalus var. carotenoides was stimulated by acetic, succinic, propionic, oxalic, malic, tartaric, citric, pyruvic, alpha-ketoglutaric and fumaric acids. Incorporation of 14C-acetate into the molecule of the antibiotic and the data on dependence of the stimulating effect upon the quantitative ratio and time of the organic acid addition were indicative of the role of acetic, succinic and propionic acids as precursors of macrotetrolides. The other organic acids increased the biosynthesis of macrotetolides when added to the culture within wide time ranges of the culture development and prolonged the period of the mycelium productive state.

  16. Content and Vacuole/Extravacuole Distribution of Neutral Sugars, Free Amino Acids, and Anthocyanin in Protoplasts 1

    PubMed Central

    Wagner, George J.

    1979-01-01

    Neutral sugar, free amino acid, and anthocyanin levels and vacuole/extravacuole distribution were determined for Hippeastrum and Tulipa petal and Tulipa leaf protoplasts. Glucose and fructose, the predominant neutral monosaccharides observed, were primarily vacuolar in location. Glutamine, the predominant free amino acid found, was primarily extravacuolar. γ-Methyleneglutamate was identified as a major constituent of Tulipa protoplasts. Qualitative characterization of Hippeastrum petal and vacuole organic acids indicated the presence of oxalic, malic, citric, and isocitric acids. Data are presented which indicate that vacuoles obtained by gentle osmotic shock of protoplasts in dibasic phosphate have good purity and retain their contents. Images PMID:16660921

  17. Amino-acid contamination of aqueous hydrochloric acid.

    NASA Technical Reports Server (NTRS)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  18. Analysis of Bile Acids

    NASA Astrophysics Data System (ADS)

    Sjövall, Jan; Griffiths, William J.; Setchell, Kenneth D. R.; Mano, Nariyasu; Goto, Junichi

    Bile acids constitute a large family of steroids in vertebrates, normally formed from cholesterol and carrying a carboxyl group in a side-chain of variable length. Bile alcohols, also formed from cholesterol, have similar structures as bile acids, except for the absence of a carboxyl group in the steroid skeleton. The conversion of cholesterol to bile acids and/or bile alcohols is of major importance for maintenance of cholesterol homeostasis, both from quantitative and regulatory points of view (Chiang, 2004; Kalaany and Mangelsdorf, 2006; Moore, Kato, Xie, et al., 2006; Scotti, Gilardi, Godio, et al., 2007). Appropriately conjugated bile acids and bile alcohols (also referred to as bile salts) are secreted in bile and serve vital functions in the absorption of lipids and lipid-soluble compounds (Hofmann, 2007). Reliable analytical methods are required for studies of the functions and pathophysiological importance of the variety of bile acids and bile alcohols present in living organisms. When combined with genetic and proteomic studies, analysis of these small molecules (in today's terminology: metabolomics, steroidomics, sterolomics, cholanoidomics, etc.) will lead to a deeper understanding of the integrated metabolic processes in lipid metabolism.

  19. Optical high acidity sensor

    DOEpatents

    Jorgensen, B.S.; Nekimken, H.L.; Carey, W.P.; O`Rourke, P.E.

    1997-07-22

    An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber. 10 figs.

  20. Optical high acidity sensor

    DOEpatents

    Jorgensen, Betty S.; Nekimken, Howard L.; Carey, W. Patrick; O'Rourke, Patrick E.

    1997-01-01

    An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and, a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber.

  1. Acid sludge utilization

    SciTech Connect

    Suarez, M.

    1980-09-01

    The Peak Oil Company of Tampa, Florida, in cooperation with the United States Department of Energy, has completed an initial study for the incorporation of acid-sludge derived from the rerefining of used lubricating oil into a useful and salable building material. Both bricks and paving materials have been produced using a formulation developed by Peak. Equipment has been designed and constructed for the specific purpose of preparing emulsions containing the acid-sludge, which is a vital ingredient in the final formulation. Testing of products obtained from these initial efforts shows that the acid in the sludge has been effectively neutralized and that heavy metals are not leached from the bricks or paving material in normal testing. While some properties of the building materials that incorporate the acid-sludge by-product are below standards for clay and shale brick, uses are defined for the product as is, and there is some promise of eventual production of building materials that meet all specifications for competitive materials. Initial cost estimations are encouraging, indicating that a profit can be derived by converting a hazardous and noxious by-product of rerefining to a construction material. Acid-sludge has presented a complex and costly disposal problem to the industry resulting in a serious depletion in the capacity for rerefining used lubricating oil.

  2. Domoic acid epileptic disease.

    PubMed

    Ramsdell, John S; Gulland, Frances M

    2014-03-01

    Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis. PMID:24663110

  3. Domoic Acid Epileptic Disease

    PubMed Central

    Ramsdell, John S.; Gulland, Frances M.

    2014-01-01

    Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis. PMID:24663110

  4. A Demonstration of Acid Rain

    ERIC Educational Resources Information Center

    Fong, Man Wai

    2004-01-01

    A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

  5. DOCOSAHEXAENOIC ACID AND ARACHIDONIC ACID PREVENT ESSENTIAL FATTY ACID DEFICIENCY AND HEPATIC STEATOSIS

    PubMed Central

    Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Fallon, Erica M.; Gura, Kathleen M.; Nose, Vania; Bistrian, Bruce R.; Puder, Mark

    2012-01-01

    Objectives Essential fatty acids are important for growth, development, and physiologic function. Alpha-linolenic acid and linoleic acid are the precursors of docosahexaenoic and arachidonic acid, respectively, and have traditionally been considered the essential fatty acids. However, we hypothesized that docosahexaenoic acid and arachidonic acid can function as the essential fatty acids. Methods Using a murine model of essential fatty acid deficiency and consequent hepatic steatosis, we provided mice with varying amounts of docosahexaenoic and arachidonic acids to determine whether exclusive supplementation of docosahexaenoic and arachidonic acids could prevent essential fatty acid deficiency and inhibit or attenuate hepatic steatosis. Results Mice supplemented with docosahexaenoic and arachidonic acids at 2.1% or 4.2% of their calories for 19 days had normal liver histology and no biochemical evidence of essential fatty acid deficiency, which persisted when observed after 9 weeks. Conclusion Supplementation of sufficient amounts of docosahexaenoic and arachidonic acids alone without alpha-linolenic and linoleic acids meets essential fatty acid requirements and prevents hepatic steatosis in a murine model. PMID:22038210

  6. Biodegradation of cyanuric acid.

    PubMed

    Saldick, J

    1974-12-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO(2) and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand.

  7. Exposures to acidic aerosols.

    PubMed

    Spengler, J D; Keeler, G J; Koutrakis, P; Ryan, P B; Raizenne, M; Franklin, C A

    1989-02-01

    Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H+ determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr H+ concentrations exceeded 550 nmole/m3 (approximately 27 micrograms/m3 H2SO4). The maximum estimated 1-hr concentration exceeded 1500 nmole/m3 for H+ ions. At these concentrations, an active child might receive more than 2000 nmole of H+ ion in 12 hr and in excess of 900 nmole during the hour when H2SO4 exceeded 50 micrograms/m3.

  8. Biodegradation of Cyanuric Acid

    PubMed Central

    Saldick, Jerome

    1974-01-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO2 and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand. PMID:4451360

  9. Inhibitory effect of organic acids on arcobacters in culture and their use for control of Arcobacter butzleri on chicken skin.

    PubMed

    Skřivanová, Eva; Molatová, Zuzana; Matěnová, Michaela; Houf, Kurt; Marounek, Milan

    2011-01-01

    The inhibitory effects of 17 organic acids (C₂-C₁₆ fatty acids, sorbic, benzoic, phenylacetic, fumaric, succinic, lactic, malic and citric) on Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii were investigated by determining their IC₅₀ values, defined as the concentration of acid at which the target DNA sequence was expressed at 50% of the positive control level in cultures incubated at 30°C for 24 h. DNA was analysed by real-time PCR. The Arcobacter strains tested were inhibited by all the organic acids, with the sensitivities in the order A. skirrowii > A. cryaerophilus > A. butzleri. Eight acids with IC₅₀ values of <1 mg/mL against A. butzleri were tested for their effects on A. butzleri inoculated on chicken carcasses at a concentration of 5 log CFU/g of skin. Inoculated halved carcasses were immersed in solutions of the acids at 5 mg/mL for 1 min. Samples of skin were collected from carcass halves after storage at 4°C for 0, 1, 2 or 3 days for enumeration of arcobacters on Muller-Hinton agar. All eight tested acids suppressed bacterial proliferation. The highest inhibitory activities were observed for benzoic, citric, malic and sorbic acids. Subsequent sensory analysis revealed benzoic acid to be the most suitable organic acid for chicken skin treatment.

  10. Calorimetry of Nucleic Acids.

    PubMed

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

    2015-12-01

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

  11. Acid rain in Asia

    NASA Astrophysics Data System (ADS)

    Bhatti, Neeloo; Streets, David G.; Foell, Wesley K.

    1992-07-01

    Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in the developing world, particularly in Asia, is much bleaker. Given the policies of many Asian nations to achieve levels of development comparable with the industrialized world—which necessitate a significant expansion of energy consumption (most derived from indigenous coal reserves)—the potential for the formation of, and damage from, acid deposition in these developing countries is very high. This article delineates and assesses the emissions patterns, meteorology, physical geology, and biological and cultural resources present in various Asian nations. Based on this analysis and the risk factors to acidification, it is concluded that a number of areas in Asia are currently vulnerable to acid rain. These regions include Japan, North and South Korea, southern China, and the mountainous portions of Southeast Asia and southwestern India. Furthermore, with accelerated development (and its attendant increase in energy use and production of emissions of acid deposition precursors) in many nations of Asia, it is likely that other regions will also be affected by acidification in the near future. Based on the results of this overview, it is clear that acid deposition has significant potential to impact the Asian region. However, empirical evidence is urgently needed to confirm this and to provide early warning of increases in the magnitude and spread of acid deposition and its effects throughout this part of the world.

  12. Effect of mitochondrial ascorbic acid synthesis on photosynthesis.

    PubMed

    Senn, M E; Gergoff Grozeff, G E; Alegre, M L; Barrile, F; De Tullio, M C; Bartoli, C G

    2016-07-01

    Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of l-galactono-1,4-lactone (l-GalL) and then distributed to different cell compartments. AA-deficient Arabidopsis thaliana mutants (vtc2) and exogenous applications of l-GalL were used to generate plants with different AA content in their leaves. This experimental approach allows determining specific AA-dependent effects on carbon metabolism. No differences in O2 uptake, malic and citric acid and NADH content suggest that AA synthesis or accumulation did not affect mitochondrial activity; however, l-GalL treatment increased CO2 assimilation and photosynthetic electron transport rate in vtc2 (but not wt) leaves demonstrating a stimulation of photosynthesis after l-GalL treatment. Increased CO2 assimilation correlated with increased leaf stomatal conductance observed in l-GalL-treated vtc2 plants.

  13. Nocturnal water storage in plants having Crassulacean acid metabolism.

    PubMed

    Lüttge, U

    1986-06-01

    Measurements of water uptake and transpiration, during the dark period of plants having Crassulacean acid metabolism (CAM) allow calculation of leaf-volume changes (ΔV). Nocturnal leaf-volume changes of CAM plants have also been reported in the literature on the basis of waterdisplacement measurements. A third way of estimation is from measurements of turgor changes and cellular water-storage capacity using the pressure probe, cytomorphometry and the Scholander pressure chamber. An extension of the interpretation of results reported in the literature shows that for leaf succulent CAM plants the three different approaches give similar values of ΔV ranging between 2.3 and 10.7% (v/v). It is evident that nocturnal malic-acid accumulation osmotically drives significant water storage in CAM leaf tissue. PMID:24232034

  14. Effect of mitochondrial ascorbic acid synthesis on photosynthesis.

    PubMed

    Senn, M E; Gergoff Grozeff, G E; Alegre, M L; Barrile, F; De Tullio, M C; Bartoli, C G

    2016-07-01

    Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of l-galactono-1,4-lactone (l-GalL) and then distributed to different cell compartments. AA-deficient Arabidopsis thaliana mutants (vtc2) and exogenous applications of l-GalL were used to generate plants with different AA content in their leaves. This experimental approach allows determining specific AA-dependent effects on carbon metabolism. No differences in O2 uptake, malic and citric acid and NADH content suggest that AA synthesis or accumulation did not affect mitochondrial activity; however, l-GalL treatment increased CO2 assimilation and photosynthetic electron transport rate in vtc2 (but not wt) leaves demonstrating a stimulation of photosynthesis after l-GalL treatment. Increased CO2 assimilation correlated with increased leaf stomatal conductance observed in l-GalL-treated vtc2 plants. PMID:27010742

  15. Acid Precipitation; (USA)

    SciTech Connect

    Rushing, J.W.; Hicks, S.C.

    1991-01-01

    This publication, Acid Precipitation (APC) announces on a monthly basis the current worldwide information on acid precipitation and closely related subjects, including wet and dry deposition, long-range transport, environmental effects, modeling, and socioeconomic factors. Information on the following subjects is included within the scope of this publication, but all subjects may not appear in each issue: Pollution sources and pollution control technology; atmospheric transport and chemistry; terrestrial transport and chemistry; aquatic transport and chemistry; biological effects; corrosive effects; and socioeconomics, policy, and legislation.

  16. Whither acid rain?

    PubMed

    Brimblecombe, P

    2001-04-01

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

  17. NITRIC ACID PICKLING PROCESS

    DOEpatents

    Boller, E.R.; Eubank, L.D.

    1958-08-19

    An improved process is described for the treatment of metallic uranium surfaces preparatory to being given hot dip coatings. The process consists in first pickling the uraniunn surInce with aqueous 50% to 70% nitric acid, at 60 to 70 deg C, for about 5 minutes, rinsing the acid solution from the uranium article, promptly drying and then passing it through a molten alkali-metal halide flux consisting of 42% LiCl, 53% KCla and 5% NaCl into a molten metal bath consisting of 85 parts by weight of zinc and 15 parts by weight of aluminum

  18. Fatty acids of Thiobacillus thiooxidans.

    PubMed

    Levin, R A

    1971-12-01

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

  19. Fatty Acids of Thiobacillus thiooxidans

    PubMed Central

    Levin, Richard A.

    1971-01-01

    Fatty acid spectra were made on Thiobacillus thiooxidans cultures both in the presence and absence of organic compounds. Small additions of glucose or acetate had no significant effect either on growth or fatty acid content. The addition of biotin had no stimulatory effect but did result in slight quantitative changes in the fatty acid spectrum. The predominant fatty acid was a C19 cyclopropane acid. PMID:4945206

  20. Hydroxycinnamic Acid Derivatives Obtained from a Commercial Crataegus Extract and from Authentic Crataegus spp.§

    PubMed Central

    Kuczkowiak, Ulrich; Petereit, Frank; Nahrstedt, Adolf

    2014-01-01

    Abstract Eleven hydroxycinnamic acid derivatives were isolated from a 70% methanolic Crataegus extract (Crataegi folium cum flore) and partly verified and quantified for individual Crataegus species (C. laevigata, C. monogyna, C. nigra, C. pentagyna) by HPLC: 3-O-(E)-p-coumaroylquinic acid (1), 5-O-(E)-p-coumaroyl-quinic acid (2), 4-O-(E)-p-coumaroylquinic acid (3), 3-O-(E)-caffeoylquinic acid (4), 4-O-(E)-caffeoylquinic acid (5), 5-O-(E)-caffeoylquinic acid (6), 3,5-di-O-(E)-caffeoylquinic acid (7), 4,5-di-O-(E)-caffeoylquinic acid (8), (-)-2-O-(E)-caffeoyl-L-threonic acid (9), (-)-4-O-(E)-caffeoyl-L-threonic acid (10), and (-)-4-O-(E)-p-coumaroyl-L-threonic acid (11). Further, (-)-2-O-(E)-caffeoyl-D-malic acid (12) was isolated from C. submollis and also identified for C. pentagyna and C. nigra by co-chromatography. The isolates 10 and 11 were not found in the authentic fresh specimen, indicating that they may be formed during extraction by acyl migration from the 2-O-acylderivatives. Also, 9 and 11 are described here for the first time. All structures were assigned on the basis of their spectroscopic data (1H-, 13C-NMR, MS, optical rotation). PMID:26171328

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

    ERIC Educational Resources Information Center

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

    2012-01-01

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

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

    PubMed

    Li, Haixing; Cao, Yusheng

    2010-11-01

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

  3. Comparison of Buffer Effect of Different Acids During Sandstone Acidizing

    NASA Astrophysics Data System (ADS)

    Umer Shafiq, Mian; Khaled Ben Mahmud, Hisham; Hamid, Mohamed Ali

    2015-04-01

    The most important concern of sandstone matrix acidizing is to increase the formation permeability by removing the silica particles. To accomplish this, the mud acid (HF: HCl) has been utilized successfully for many years to stimulate the sandstone formations, but still it has many complexities. This paper presents the results of laboratory investigations of different acid combinations (HF: HCl, HF: H3PO4 and HF: HCOOH). Hydrofluoric acid and fluoboric acid are used to dissolve clays and feldspar. Phosphoric and formic acids are added as a buffer to maintain the pH of the solution; also it allows the maximum penetration of acid into the core sample. Different tests have been performed on the core samples before and after the acidizing to do the comparative study on the buffer effect of these acids. The analysis consists of permeability, porosity, color change and pH value tests. There is more increase in permeability and porosity while less change in pH when phosphoric and formic acids were used compared to mud acid. From these results it has been found that the buffer effect of phosphoric acid and formic acid is better than hydrochloric acid.

  4. [Studies on interaction of acid-treated nanotube titanic acid and amino acids].

    PubMed

    Zhang, Huqin; Chen, Xuemei; Jin, Zhensheng; Liao, Guangxi; Wu, Xiaoming; Du, Jianqiang; Cao, Xiang

    2010-06-01

    Nanotube titanic acid (NTA) has distinct optical and electrical character, and has photocatalysis character. In accordance with these qualities, NTA was treated with acid so as to enhance its surface activity. Surface structures and surface groups of acid-treated NTA were characterized and analyzed by Transmission Electron Microscope (TEM) and Fourier Transform Infrared Spectrometry (FT-IR). The interaction between acid-treated NTA and amino acids was investigated. Analysis results showed that the lengths of acid-treated NTA became obviously shorter. The diameters of nanotube bundles did not change obviously with acid-treating. Meanwhile, the surface of acid-treated NTA was cross-linked with carboxyl or esterfunction. In addition, acid-treated NTA can catch amino acid residues easily, and then form close combination.

  5. Expression, purification, and characterization of NADP+-dependent malic enzyme from the oleaginous fungus Mortierella alpina.

    PubMed

    Yang, Jiayu; Hu, Xinjie; Zhang, Huaiyuan; Chen, Haiqin; Kargbo, M'balu R; Zhao, Jianxin; Song, Yuanda; Chen, Yong Q; Zhang, Hao; Chen, Wei

    2014-08-01

    Malic enzymes are a class of oxidative decarboxylases that catalyze the oxidative decarboxylation of malate to pyruvate and carbon dioxide, with concomitant reduction of NAD(P)+ to NAD(P)H. The NADP+-dependent malic enzyme in oleaginous fungi plays a key role in fatty acid biosynthesis. In this study, the malic enzyme-encoding complementary DNA (cDNA) (malE1) from the oleaginous fungus Mortierella alpina was cloned and expressed in Escherichia coli BL21 (DE3). The recombinant protein (MaME) was purified using Ni-NTA affinity chromatography. The purified enzyme used NADP+ as the cofactor. The K m values for L-malate and NADP+ were 2.19±0.01 and 0.38±0.02 mM, respectively, while the V max values were 147±2 and 302±14 U/mg, respectively, at the optimal condition of pH 7.5 and 33 °C. MaME is active in the presence of Mn2+, Mg2+, Co2+, Ni2+, and low concentrations of Zn2+ rather than Ca2+, Cu2+, or high concentrations of Zn2+. Oxaloacetic acid and glyoxylate inhibited the MaME activity by competing with malate, and their K i values were 0.08 and 0.6 mM, respectively.

  6. Molecular cloning and characterization of a malic enzyme gene from the oleaginous yeast Lipomyces starkeyi.

    PubMed

    Tang, Wei; Zhang, Sufang; Tan, Haidong; Zhao, Zongbao K

    2010-06-01

    The malic enzyme-encoding cDNA (GQ372891) from the oleaginous yeast Lipomyces starkeyi AS 2.1560 was isolated, which has an 1719-bp open reading frame flanked by a 290-bp 5' untranslated sequence and a 92-bp 3' untranslated sequence. The proposed gene, LsME1, encoded a protein with 572 amino acid residues. The protein presented 58% sequence identity with the malic enzymes from Yarrowia lipolytica CLIB122 and Aspergillus fumigatus Af293. The LsME1 gene was cloned into the vector pMAL-p4x to express a fusion protein (MBP-LsME1) in Escherichia coli TB1. The fusion protein was purified and then cleaved by Factor Xa to give the recombinant LsME1. This purified enzyme took either NAD(+) or NADP(+) as the coenzyme but preferred NAD(+). The K (m) values for malic acid, NAD(+) and NADP(+) were 0.85 +/- 0.05 mM, 0.34 +/- 0.08 mM, and 7.4 +/- 0.32 mM, respectively, at pH 7.3.

  7. Docosahexaenoic acid and lactation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Docosahexaenoic acid (DHA) is an important component of membrane phospholipids in the retina, and brain, and accumulates rapidly in these tissues during early infancy. DHA is present in human milk, but the amount varies considerably and is largely dependent on maternal diet. This article reviews dat...

  8. Orphenadrinium picrate picric acid

    PubMed Central

    Fun, Hoong-Kun; Hemamalini, Madhukar; Siddaraju, B. P.; Yathirajan, H. S.; Narayana, B.

    2010-01-01

    The asymmetric unit of the title compound N,N-dimethyl-2-[(2-methyl­phen­yl)phenyl­meth­oxy]ethanaminium picrate picric acid, C18H24NO+·C6H2N3O7 −·C6H3N3O7, contains one orphenadrinium cation, one picrate anion and one picric acid mol­ecule. In the orphenadrine cation, the two aromatic rings form a dihedral angle of 70.30 (7)°. There is an intra­molecular O—H⋯O hydrogen bond in the picric acid mol­ecule, which generates an S(6) ring motif. In the crystal structure, the orphenadrine cations, picrate anions and picric acid mol­ecules are connected by strong inter­molecular N—H⋯O hydrogen bonds, π⋯π inter­actions between the benzene rings of cations and anions [centroid–centroid distance = 3.5603 (9) Å] and weak C—H⋯O hydrogen bonds, forming a three-dimensional network. PMID:21580426

  9. Acid Rain Investigations.

    ERIC Educational Resources Information Center

    Hugo, John C.

    1992-01-01

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

  10. The Acid Rain Debate.

    ERIC Educational Resources Information Center

    Oates-Bockenstedt, Catherine

    1997-01-01

    Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

  11. Acid rain bibliography

    SciTech Connect

    Sayers, C.S.

    1983-09-01

    This bibliography identifies 900 citations on various aspects of Acid Rain, covering published bibliographies, books, reports, conference and symposium proceedings, audio visual materials, pamphlets and newsletters. It includes five sections: citations index (complete record of author, title, source, order number); KWIC index; title index; author index; and source index. 900 references.

  12. Acid Rain Classroom Projects.

    ERIC Educational Resources Information Center

    Demchik, Michael J.

    2000-01-01

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

  13. The Acid Rain Debate.

    ERIC Educational Resources Information Center

    Bybee, Rodger; And Others

    1984-01-01

    Describes an activity which provides opportunities for role-playing as industrialists, ecologists, and government officials. The activity involves forming an international commission on acid rain, taking testimony, and, based on the testimony, making recommendations to governments on specific ways to solve the problem. Includes suggestions for…

  14. The Acid Rain Game.

    ERIC Educational Resources Information Center

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

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

  15. Targeting tumor acidity

    NASA Astrophysics Data System (ADS)

    Reshetnyak, Yana K.; Engelman, Donald M.; Andreev, Oleg A.

    2012-02-01

    One of the main features of solid tumors is extracellular acidity, which correlates with tumor aggressiveness and metastatic potential. We introduced novel approach in targeting of acidic tumors, and translocation of cell-impermeable cargo molecules across cellular membrane. Our approach is based on main principle of insertion and folding of a polypeptide in lipid bilayer of membrane. We have identified family of pH Low Insertion Peptides (pHLIPs), which are capable spontaneous insertion and folding in membrane at mild acidic conditions. The affinity of peptides of pHLIP family to membrane at low pH is several times higher than at neutral pH. The process of peptides folding occurs within milliseconds. The energy released in a result of folding (about 2 kcal/mol) could be used to move polar cargo across a membrane, which is a novel concept in drug delivery. pHLIP peptides could be considered as a pH-sensitive single peptide molecular transporters and conjugated with imaging probes for fluorescence, MR, PET and SPECT imaging, they represent a novel in vivo marker of acidity. The work is supported by NIH grants CA133890 and GM073857 to OAA, DME, YRK.

  16. Spermatotoxicity of dichloroacetic acid

    EPA Science Inventory

    The testicular toxicity of dichloroacetic acid (DCA), a disinfection byproduct of drinking water, was evaluated in adult male rats given both single and multiple (up to 14 d) oral doses. Delayed spermiation and altered resorption of residual bodies were observed in rats given sin...

  17. Plant fatty acid hydroxylase

    DOEpatents

    Somerville, Chris; van de Loo, Frank

    2000-01-01

    The present invention relates to the identification of nucleic acid sequences and constructs, and methods related thereto, and the use of these sequences and constructs to produce genetically modified plants for the purpose of altering the composition of plant oils, waxes and related compounds.

  18. Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite

    NASA Technical Reports Server (NTRS)

    Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

    1992-01-01

    Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

  19. Growth and survival of Escherichia coli O157:H7 under acidic conditions.

    PubMed Central

    Conner, D E; Kotrola, J S

    1995-01-01

    The effect of pH reduction with acetic (pH 5.2), citric (pH 4.0), lactic (pH 4.7), malic (pH 4.0), mandelic (pH 5.0), or tartaric (pH 4.1) acid on growth and survival of Escherichia coli O157:H7 in tryptic soy broth with 0.6% yeast extract held at 25, 10, or 4 degrees C for 56 days was determined. Triplicate flasks were prepared for each acid treatment at each temperature. At 25 degrees C, populations increased 2 to 4 log10 CFU/ml in all treatments except that with mandelic acid, whereas no growth occurred at 10 or 4 degrees C in any treatments except the control. However, at all sampling times, higher (P < 0.05) populations were recovered from treatments held at 4 degrees C than from those held at 10 degrees C. At 10 degrees C, E. coli O157:H7 was inactivated at higher rates in citric, malic, and mandelic acid treatments than in the other treatments. At the pH values tested, the presence of the organic acids enhanced survival of the pathogen at 4 degrees C compared with the unacidified control. E. coli O157:H7 has the ability to survive in acidic conditions (pH, > or = 4.0) for up to 56 days, but survival is affected by type of acidulant and temperature. PMID:7887621

  20. Nematicidal Activity of Kojic Acid Produced by Aspergillus oryzae against Meloidogyne incognita.

    PubMed

    Kim, Tae Yoon; Jang, Ja Yeong; Jeon, Sun Jeong; Lee, Hye Won; Bae, Chang-Hwan; Yeo, Joo Hong; Lee, Hyang Burm; Kim, In Seon; Park, Hae Woong; Kim, Jin-Cheol

    2016-08-28

    The fungal strain EML-DML3PNa1 isolated from leaf of white dogwood (Cornus alba L.) showed strong nematicidal activity with juvenile mortality of 87.6% at a concentration of 20% fermentation broth filtrate at 3 days after treatment. The active fungal strain was identified as Aspergillus oryzae, which belongs to section Flavi, based on the morphological characteristics and sequence analysis of the ITS rDNA, calmodulin (CaM), and β-tubulin (BenA) genes. The strain reduced the pH value to 5.62 after 7 days of incubation. Organic acid analysis revealed the presence of citric acid (515.0 mg/kg), malic acid (506.6 mg/kg), and fumaric acid (21.7 mg/kg). The three organic acids showed moderate nematicidal activities, but the mixture of citric acid, malic acid, and fumaric acid did not exhibit the full nematicidal activity of the culture filtrate of EML- DML3PNa1. Bioassay-guided fractionation coupled with (1)H- and (13)C-NMR and EI-MS analyses led to identification of kojic acid as the major nematicidal metabolite. Kojic acid exhibited dose-dependent mortality and inhibited the hatchability of M. incognita, showing EC50 values of 195.2 µg/ml and 238.3 µg/ml, respectively, at 72 h postexposure. These results suggest that A. oryzae EML-DML3PNa1 and kojic acid have potential as a biological control agent against M. incognita.

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

    SciTech Connect

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

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

  2. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by...

  3. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by...

  4. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by...

  5. Synthesis of acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters

    DOEpatents

    Moens, Luc

    2003-06-24

    A process of preparing an acid addition salt of delta-aminolevulinc acid comprising: a) dissolving a lower alkyl 5-bromolevulinate and hexamethylenetetramine in a solvent selected from the group consisting of water, ethyl acetate, chloroform, acetone, ethanol, tetrahydrofuran and acetonitrile, to form a quaternary ammonium salt of the lower alkyl 5-bromolevulinate; and b) hydrolyzing the quaternary ammonium salt with an inorganic acid to form an acid addition salt of delta-aminolevulinic acid.

  6. Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations.

    PubMed

    Ahmad, I; Ali Sheraz, M; Ahmed, S; Shad, Z; Vaid, F H M

    2012-06-01

    This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations.

  7. [Influence of Three Low-Molecular-Weight Organic Acids on the Adsorption of Phenanthrene in Purple Soil].

    PubMed

    Xie, Li; Chen, Ben-shou; Zhang, Jin-zhong; Lu, Song; Jiang, Tao

    2016-03-15

    The effects of three low-molecular-weight organic acids (citric acid, malic acid and oxalic acid) on the adsorption of phenanthrene in purple soil were studied by static adsorption experiment. The results showed that the adsorption kinetic process of phenanthrene in purple soil could be described by the second-order kinetic model, and the adsorption rate constant would significantly decrease in the presence of the three low-molecular-weight organic acids ( LMWOAs). The adsorption thermodynamic process could be well described by linear adsorption model, which was dominated by distribution role. The three LMWOAs could promote the adsorption of phenantherene in purple soil when their concentrations were less than 5 mmol · L⁻¹, whereas inhibit the adsorption when their concentrations were more than 10 mmol · L⁻¹, and the inhibition would increase with increasing concentrations. Moreover, the inhibitory ability displayed a decreasing order of citric acid, oxalic acid, and malic acid when their concentrations were 20 mmol · L⁻¹, which is related to the molecular structure and acidity of the three LMWOAs. Compared with the control, the content of dissolved organic matter (DOM) released from purple soil showed a trend of first decrease and then increase with increasing LMWOAs concentration, and the adsorption capacity of phenanthrene in purple soil was negatively related to DOM content. PMID:27337897

  8. Inhibitory effects of chitosan coating combined with organic acids on Listeria monocytogenes in refrigerated ready-to-eat shrimps.

    PubMed

    Li, Min; Wang, Wen; Fang, Weihuan; Li, Yanbin

    2013-08-01

    Chitosan and organic acids are natural preservatives with proven antimicrobial efficacies. This study investigated the effects of chitosan coating combined with organic acids on inhibiting Listeria monocytogenes in ready-to-eat (RTE) shrimps during storage at 4°C. Cooked shrimps inoculated with L. monocytogenes were coated with 0.5 and 1 % chitosan solutions in combination with 2 % organic acids (acetic, citric, lactic, and malic acids) for 5 min and then stored at 4°C for 16 days. Bacterial counts, pH, and sensory properties were analyzed every 4 days. The results indicated that the antimicrobial effects of chitosan were significantly enhanced (P < 0.05) when it was combined with 2 % acetic, citric, lactic, or malic acid. Chitosan at 1 % combined with 2 % acetic acid was the most effective treatment, which caused a 5.38-log CFU/g bacterial reduction after 16 days in comparison with the controls. Transmission electron microscopy further confirmed the enhanced antimicrobial effects of the combination of chitosan and organic acids. Such combined treatments also maintained the sensory properties of RTE shrimps. The use of chitosan coating combined with organic acids significantly lowered (P < 0.05) the pH values of RTE shrimps compared with the use of chitosan alone. Therefore, we conclude that chitosan coating combined with acetic acid could be a promising antimicrobial method to prevent the proliferation of L. monocytogenes in RTE shrimps with extended shelf life.

  9. [Influence of Three Low-Molecular-Weight Organic Acids on the Adsorption of Phenanthrene in Purple Soil].

    PubMed

    Xie, Li; Chen, Ben-shou; Zhang, Jin-zhong; Lu, Song; Jiang, Tao

    2016-03-15

    The effects of three low-molecular-weight organic acids (citric acid, malic acid and oxalic acid) on the adsorption of phenanthrene in purple soil were studied by static adsorption experiment. The results showed that the adsorption kinetic process of phenanthrene in purple soil could be described by the second-order kinetic model, and the adsorption rate constant would significantly decrease in the presence of the three low-molecular-weight organic acids ( LMWOAs). The adsorption thermodynamic process could be well described by linear adsorption model, which was dominated by distribution role. The three LMWOAs could promote the adsorption of phenantherene in purple soil when their concentrations were less than 5 mmol · L⁻¹, whereas inhibit the adsorption when their concentrations were more than 10 mmol · L⁻¹, and the inhibition would increase with increasing concentrations. Moreover, the inhibitory ability displayed a decreasing order of citric acid, oxalic acid, and malic acid when their concentrations were 20 mmol · L⁻¹, which is related to the molecular structure and acidity of the three LMWOAs. Compared with the control, the content of dissolved organic matter (DOM) released from purple soil showed a trend of first decrease and then increase with increasing LMWOAs concentration, and the adsorption capacity of phenanthrene in purple soil was negatively related to DOM content.

  10. Urea-acetylene dicarboxylic acid reaction: A likely pathway for prebiotic uracil formation

    NASA Astrophysics Data System (ADS)

    Subbaraman, A. S.; Kazi, Z. A.; Choughuley, A. S. U.; Chadha, M. S.

    1980-12-01

    A number of routes have been suggested for the prebiotic synthesis of uracil involving the reaction of urea with malic acid, propiolic acid, cyanoacetylene and others. Cyanoacetylene has been detected in the interstellar medium as well as simulated prebiotic experiments. It is therefore plausible that dicyanoacetylene and its hydrolytic product acetylene dicarboxylic acid, (ADCA) may have played a role in chemical evolution. This aspect has been examined in the present work for the synthesis of uracil from ADCA and urea reaction. It was found that when ADCA reacted with urea, uracil was formed only in the presence of phosphoric acid and phosphates. Ammonium phosphates gave higher yields of uracil than other phosphates. In the absence of phosphoric acid or phosphates no uracil formation took place. This type of synthesis could have taken place in prebiotic oceans which contained ammonium phosphates and other salts.

  11. Microbial production of specialty organic acids from renewable and waste materials.

    PubMed

    Alonso, Saúl; Rendueles, Manuel; Díaz, Mario

    2015-01-01

    Microbial production of organic acids has become a fast-moving field due to the increasing role of these compounds as platform chemicals. In recent years, the portfolio of specialty fermentation-derived carboxylic acids has increased considerably, including the production of glyceric, glucaric, succinic, butyric, xylonic, fumaric, malic, itaconic, lactobionic, propionic and adipic acid through innovative fermentation strategies. This review summarizes recent trends in the use of novel microbial platforms as well as renewable and waste materials for efficient and cost-effective bio-based production of emerging high-value organic acids. Advances in the development of robust and efficient microbial bioprocesses for producing carboxylic acids from low-cost feedstocks are also discussed. The industrial market scenario is also reviewed, including the latest information on the stage of development for producing these emerging bio-products via large-scale fermentation.

  12. Fatty acid-producing hosts

    DOEpatents

    Pfleger, Brian F; Lennen, Rebecca M

    2013-12-31

    Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

  13. Acid diffusion through polyaniline membranes

    SciTech Connect

    Su, T.M.; Huang, S.C.; Conklin, J.A.

    1995-12-01

    Polyaniline membranes in the undoped (base) and doped (acid) forms are studied for their utility as pervaporation membranes. The separation of water from mixtures of propionic acid, acetic acid and formic acid have been demonstrated from various feed compositions. Doped polyaniline displays an enhanced selectivity of water over these organic acids as compared with undoped polyaniline. For as-cast polyaniline membranes a diffusion coefficient (D) on the order of 10{sup -9} cm{sup 2}/sec has been determined for the flux of protons through the membranes using hydrochloric acid.

  14. Potential antibacterial activity of coumarin and coumarin-3-acetic acid derivatives.

    PubMed

    Chattha, Fauzia Anjum; Munawar, Munawar Ali; Nisa, Mehrun; Ashraf, Mohammad; Kousar, Samina; Arshad, Shafia

    2015-05-01

    Coumarin and coumarin-3-acetic acid derivatives were synthesized by reacting phenols with malic acid, ethyl acetoacetate and ethyl acetylsuccinate in appropriate reaction conditions. All synthesized compounds were subjected to test for their antimicrobial activities against variety of gram positive (Bacillus subtilis, Staphylococcus aureus) and gram negative bacterial stains (Shigella sonnei, Escherichia coli) by agar dilution method. Several of them exhibited appreciable good antibacterial activity against the different strains of gram positive and gram negative bacteria. These findings suggest a great potential of these compounds for screening and use as antibacterial agents for further studies with a battery of bacteria.

  15. α-hydroxy acids mediated synthesis of hollow silver nanoshells and their optical properties

    NASA Astrophysics Data System (ADS)

    Dadhich, B.; Saha, A.; Priyam, A.

    2016-05-01

    The α-hydroxy-acids (i.e. glycolic, malic, citric) plays crucial role in the formation of hollow silver nanoshells and in its plasmonic properties. The SPR peak varied in a wide range from 400-527 nm with variation in chain length and molar concentration or ratio of the acids. The stability was also affected by chain length. Zeta potential analyzed for the stability of hollow silver nanoshells (HAgNS). The hollow structure of these nanocrystals with aspect ratio (Outer diameter/ shell thickness) 2 to 5 is confirmed by HR-TEM.

  16. Treatment of Bile Acid Amidation Defects with Glycocholic Acid

    PubMed Central

    Heubi, James E.; Setchell, Kenneth D.R.; Jha, Pinky; Buckley, Donna; Zhang, Wujuan; Rosenthal, Philip; Potter, Carol; Horslen, Simon; Suskind, David

    2014-01-01

    Bile acid amidation defects were predicted to present with fat/fat soluble vitamin malabsorption with minimal cholestasis. We identified and treated 5 patients (1 male/4 females) from 4 families with defective bile acid amidation due to a genetically confirmed deficiency in bile acid CoA:amino acid N-acyl transferase (BAAT) with the conjugated bile acid, glycocholic acid (GCA). Fast atom bombardment-mass spectrometry analysis of urine and bile at baseline revealed predominantly unconjugated cholic acid and absence of the usual glycine and taurine conjugated primary bile acids. Treatment with 15 mg/kg GCA resulted in total duodenal bile acid concentrations of 23.3 ± 19.1 mmol/L (mean ± SD) and 63.5 ± 4.0% of the bile acids were secreted in bile in the conjugated form of which GCA represented 59.6 ± 9.3% of the total biliary bile acids. Unconjugated cholic acid continued to be present in high concentrations in bile because of partial intestinal deconjugation of orally administered GCA. Serum total bile acid concentrations did not significantly differ between pretreatment and post-treatment samples and serum contained predominantly unconjugated cholic acid. These findings confirmed efficient intestinal absorption, hepatic extraction and biliary secretion of the administered GCA. Oral tolerance tests for vitamin D2 (1000 IU vitamin D2/kg) and tocopherol (100 IU/kg tocopherol acetate) demonstrated improvement in fat-soluble vitamin absorption after GCA treatment. Growth improved in 3/3 growth-delayed prepubertal patients. Conclusions: Oral glycocholic acid therapy is safe and effective in improving growth and fat-soluble vitamin absorption in children and adolescents with inborn errors of bile acid metabolism due to amidation defects. PMID:25163551

  17. [Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis].

    PubMed

    Lin, Zhangnan; Liu, Hongjuan; Zhang, Jian'an; Wang, Gehua

    2016-03-01

    Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis. PMID:27349116

  18. Pseudomonas lini Strain ZBG1 Revealed Carboxylic Acid Utilization and Copper Resistance Features Required for Adaptation to Vineyard Soil Environment: A Draft Genome Analysis

    PubMed Central

    Chan, Kok-Gan; Chong, Teik-Min; Adrian, Tan-Guan-Sheng; Kher, Heng Leong; Grandclément, Catherine; Faure, Denis; Yin, Wai-Fong; Dessaux, Yves; Hong, Kar-Wai

    2016-01-01

    Pseudomonas lini strain ZBG1 was isolated from the soil of vineyard in Zellenberg, France and the draft genome was reported in this study. Bioinformatics analyses of the genome revealed presence of genes encoding tartaric and malic acid utilization as well as copper resistance that correspond to the adaptation this strain in vineyard soil environment. PMID:27512520

  19. Comparing organic acids and salt derivatives as antimicrobials against selected poultry-borne Listeria monocytogenes strains in vitro.

    PubMed

    Lues, Jan Frederick Rykers; Theron, Maria Magdalena

    2012-12-01

    This article reports on the antilisterial properties of selected organic acids and salt derivatives in order to suggest possible alternatives in food preservation and pathogen control in the poultry meat processing industry. The susceptibility of two Listeria monocytogenes isolates was assessed against five organic acids (lactic, acetic, malic, citric, and propionic) and two acid-salt derivatives (sorbic acid [potassium salt] and benzoic acid [sodium salt]) across a series of pH environments. Minimum inhibitory concentrations (MICs) of the acids were tested against the two strains by means of an agar-dilution method. In general, strain CC60 was found to be more resistant than strain CC77 to both organic acids and salts. At pH values of 7 and above, high MIC levels (low susceptibility) were noted for potassium sorbate, sodium benzoate, and lactic acids, whereas susceptibility at lower pH increased reaching pH5 where the isolates were susceptible to all the organic acids tested. A small increase in pH notably reduced antimicrobial activity against the organisms. At pH 7, the isolates just about lost susceptibility to benzoic, lactic, malic, and sorbic acids. Although the activity of the majority of acids was linked to pH, some acids were not as closely related (e.g., potassium sorbate, sodium benzoate, and citric acid), and this suggests that the type of organic acids plays a role in inhibition. The relatively high MICs reported for compounds that are conventionally used as preservatives against Listeria spp. raise concern. The results furthermore suggest that the type of organic acid used to set pH, and not only pH alone, plays a role in determining inhibition. It was confirmed that a "one size fits all" approach to preservation is not always effective. Furthermore, the need for microbiological data to the subspecies level to inform the selection of preservatives was highlighted. PMID:23190165

  20. Eight salts constructed from 4-phenylthiazol-2-amine and carboxylic acid derivatives through combination of strong hydrogen bonding and weak noncovalent interactions

    NASA Astrophysics Data System (ADS)

    Jin, Shouwen; Zhu, Qiaowang; Wei, ShuaiShuai; Wang, Daqi

    2013-10-01

    Eight crystalline organic salts derived from 4-phenylthiazol-2-amine and carboxylic acid derivatives (2-chloronicotinic acid, 3-hydroxy-2-naphthoic acid, p-nitrobenzoic acid, 2-hydroxy-5-(phenyldiazenyl)benzoic acid, 5-nitrosalicylic acid, 5-sulfosalicylic acid, oxalic acid, and L-malic acid) were prepared and characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. In all of the salts except 6, 7, and 8, the 4-phenylthiazol-2-amine and carboxylic acid components are held together by two fused heterosynthons: a R22(7) heterosynthon and a R22(8) heterosynthon. All supramolecular architectures of the organic salts 1-8 involve extensive Nsbnd H⋯O hydrogen bonds as well as other noncovalent interactions. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. The salts displayed 2D/3D framework structure under these weak interactions.

  1. NAPAP (National Acid Precipitation Assessment Program) results on acid rain

    SciTech Connect

    Not Available

    1990-06-01

    The National Acid Precipitation Assessment Program (NAPAP) was mandated by Congress in 1980 to study the effects of acid rain. The results of 10 years of research on the effect of acid deposition and ozone on forests, particularly high elevation spruce and fir, southern pines, eastern hardwoods and western conifers, will be published this year.

  2. Acid Earth--The Global Threat of Acid Pollution.

    ERIC Educational Resources Information Center

    McCormick, John

    Acid pollution is a major international problem, but the debate it has elicited has often clouded the distinction between myth and facts. This publication attempts to concerning the acid pollution situation. This publication attempts to identify available facts. It is the first global review of the problem of acid pollution and the first to…

  3. Usnic acid controls the acidity tolerance of lichens.

    PubMed

    Hauck, Markus; Jürgens, Sascha-René

    2008-11-01

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

  4. College Chemistry Students' Mental Models of Acids and Acid Strength

    ERIC Educational Resources Information Center

    McClary, LaKeisha; Talanquer, Vicente

    2011-01-01

    The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research…

  5. Acid hydrolysis of cellulose

    SciTech Connect

    Salazar, H.

    1980-12-01

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

  6. [Progress in glucaric acid].

    PubMed

    Qiu, Yuying; Fang, Fang; Du, Guocheng; Chen, Jian

    2015-04-01

    Glucaric acid (GA) is derived from glucose and commonly used in chemical industry. It is also considered as one of the "Top value-added chemicals from biomass" as carbohydrate monomers to produce various synthetic polymers and bioenergy. The demand for GA in food manufacture is increasing. GA has also attracted public attentions due to its therapeutic uses such as regulating hormones, increasing the immune function and reducing the risks of cancers. Currently GA is produced by chemical oxidation. Research on production of GA via microbial synthesis is still at preliminary stage. We reviewed the advances of glucaric acid applications, preparation and quantification methods. The prospects on production of GA by microbial fermentation were also discussed. PMID:26380405

  7. Eucomic acid methanol monosolvate

    PubMed Central

    Li, Guo-Qiang; Li, Yao-Lan; Wang, Guo-Cai; Liang, Zhi-Hong; Jiang, Ren-Wang

    2011-01-01

    In the crystal structure of the title compound [systematic name: 2-hy­droxy-2-(4-hy­droxy­benz­yl)butane­dioic acid methanol monosolvate], C11H12O6·CH3OH, the dihedral angles between the planes of the carboxyl groups and the benzene ring are 51.23 (9) and 87.97 (9)°. Inter­molecular O—H⋯O hydrogen-bonding inter­actions involving the hy­droxy and carb­oxy­lic acid groups and the methanol solvent mol­ecule give a three-dimensional structure. PMID:22091200

  8. Industrial ecotoxicology "acid rain".

    PubMed

    Astolfi, E; Gotelli, C; Higa, J

    1986-01-01

    The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent. PMID:3758667

  9. Industrial ecotoxicology "acid rain".

    PubMed

    Astolfi, E; Gotelli, C; Higa, J

    1986-01-01

    The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent.

  10. (Radioiodinated free fatty acids)

    SciTech Connect

    Knapp, Jr., F. F.

    1987-12-11

    The traveler participated in the Second International Workshop on Radioiodinated Free Fatty Acids in Amsterdam, The Netherlands where he presented an invited paper describing the pioneering work at the Oak Ridge National Laboratory (ORNL) involving the design, development and testing of new radioiodinated methyl-branched fatty acids for evaluation of heart disease. He also chaired a technical session on the testing of new agents in various in vitro and in vivo systems. He also visited the Institute for Clinical and Experimental Nuclear Medicine in Bonn, West Germany, to review, discuss, plan and coordinate collaborative investigations with that institution. In addition, he visited the Cyclotron Research Center in Liege, Belgium, to discuss continuing collaborative studies with the Osmium-191/Iridium-191m radionuclide generator system, and to complete manuscripts and plan future studies.

  11. Changes on organic acid secretion and accumulation in Plantago almogravensis Franco and Plantago algarbiensis Samp. under aluminum stress.

    PubMed

    Martins, Neusa; Gonçalves, Sandra; Andrade, Paula B; Valentão, Patrícia; Romano, Anabela

    2013-01-01

    We investigated the effect of Al (400μM) on organic acids secretion, accumulation and metabolism in Plantago almogravensis Franco and Plantago algarbiensis Samp. Al induced a significant reduction on root elongation only in P. algarbiensis. Both species accumulated considerable amounts of Al (>120μgg(-1)) in their tissues, roots exhibiting the highest contents (>900μgg(-1)). Al stimulated malonic acid secretion in P. algarbiensis, while citric, succinic and malic acids were secreted by P. almogravensis. Moreover, Al uptake was accompanied by substantial increases of citric, oxalic, malonic and fumaric acids contents in the plantlets of either species. Overall, the acid metabolizing enzymes were not directly involved in the Al induced organic acid secretion and accumulation. Our data suggest that Al detoxification in P. almogravensis implies both secretion of organic acids from roots and tolerance to high Al tissue concentrations, while in P. algarbiensis only the tolerance mechanism seems to be involved. PMID:23199681

  12. Changes on organic acid secretion and accumulation in Plantago almogravensis Franco and Plantago algarbiensis Samp. under aluminum stress.

    PubMed

    Martins, Neusa; Gonçalves, Sandra; Andrade, Paula B; Valentão, Patrícia; Romano, Anabela

    2013-01-01

    We investigated the effect of Al (400μM) on organic acids secretion, accumulation and metabolism in Plantago almogravensis Franco and Plantago algarbiensis Samp. Al induced a significant reduction on root elongation only in P. algarbiensis. Both species accumulated considerable amounts of Al (>120μgg(-1)) in their tissues, roots exhibiting the highest contents (>900μgg(-1)). Al stimulated malonic acid secretion in P. algarbiensis, while citric, succinic and malic acids were secreted by P. almogravensis. Moreover, Al uptake was accompanied by substantial increases of citric, oxalic, malonic and fumaric acids contents in the plantlets of either species. Overall, the acid metabolizing enzymes were not directly involved in the Al induced organic acid secretion and accumulation. Our data suggest that Al detoxification in P. almogravensis implies both secretion of organic acids from roots and tolerance to high Al tissue concentrations, while in P. algarbiensis only the tolerance mechanism seems to be involved.

  13. Immunomodulatory spherical nucleic acids.

    PubMed

    Radovic-Moreno, Aleksandar F; Chernyak, Natalia; Mader, Christopher C; Nallagatla, Subbarao; Kang, Richard S; Hao, Liangliang; Walker, David A; Halo, Tiffany L; Merkel, Timothy J; Rische, Clayton H; Anantatmula, Sagar; Burkhart, Merideth; Mirkin, Chad A; Gryaznov, Sergei M

    2015-03-31

    Immunomodulatory nucleic acids have extraordinary promise for treating disease, yet clinical progress has been limited by a lack of tools to safely increase activity in patients. Immunomodulatory nucleic acids act by agonizing or antagonizing endosomal toll-like receptors (TLR3, TLR7/8, and TLR9), proteins involved in innate immune signaling. Immunomodulatory spherical nucleic acids (SNAs) that stimulate (immunostimulatory, IS-SNA) or regulate (immunoregulatory, IR-SNA) immunity by engaging TLRs have been designed, synthesized, and characterized. Compared with free oligonucleotides, IS-SNAs exhibit up to 80-fold increases in potency, 700-fold higher antibody titers, 400-fold higher cellular responses to a model antigen, and improved treatment of mice with lymphomas. IR-SNAs exhibit up to eightfold increases in potency and 30% greater reduction in fibrosis score in mice with nonalcoholic steatohepatitis (NASH). Given the clinical potential of SNAs due to their potency, defined chemical nature, and good tolerability, SNAs are attractive new modalities for developing immunotherapies.

  14. Acid rain in Asia

    SciTech Connect

    Bhatti, N.; Streets, D.G. ); Foell, W.K. )

    1991-01-01

    Acid rain has been an issue of widespread concern in North America and Europe for more than fifteen years. However, there is an emerging feeling that the problem in Europe and North America is nearing solution, largely as a result of existing and newly enacted legislation, decreased energy use due to conservation and efficiency improvements, and/or trends in energy policy away from fossil fuels. The situation in Asia appears much bleaker. Fossil fuels are already used in large quantities, such that local air pollution is becoming a serious problem and high deposition levels are being measured. Emission regulations in most countries (with the notable exception of Japan) are not very stringent. Energy plans in many countries (particularly PRC, India, Thailand, and South Korea) call for very large increases in coal combustion in the future. Finally, there is not presently a strong scientific or public constituency for action to mitigate the potential effects of acid deposition. These factors imply potentially serious problems in the future for long-range transport and deposition of sulfur and nitrogen species and consequent damage to ecosystems and materials. The political ramifications of transboundary environmental pollution in this region are also potentially serious. The purpose of this paper is to provide background information on the acid deposition situation in Asia, with the intention of laying the foundation for the development of a possible research program for this region. 36 refs., 8 figs., 8 tabs.

  15. Immunomodulatory spherical nucleic acids

    PubMed Central

    Radovic-Moreno, Aleksandar F.; Chernyak, Natalia; Mader, Christopher C.; Nallagatla, Subbarao; Kang, Richard S.; Hao, Liangliang; Walker, David A.; Halo, Tiffany L.; Merkel, Timothy J.; Rische, Clayton H.; Anantatmula, Sagar; Burkhart, Merideth; Mirkin, Chad A.; Gryaznov, Sergei M.

    2015-01-01

    Immunomodulatory nucleic acids have extraordinary promise for treating disease, yet clinical progress has been limited by a lack of tools to safely increase activity in patients. Immunomodulatory nucleic acids act by agonizing or antagonizing endosomal toll-like receptors (TLR3, TLR7/8, and TLR9), proteins involved in innate immune signaling. Immunomodulatory spherical nucleic acids (SNAs) that stimulate (immunostimulatory, IS-SNA) or regulate (immunoregulatory, IR-SNA) immunity by engaging TLRs have been designed, synthesized, and characterized. Compared with free oligonucleotides, IS-SNAs exhibit up to 80-fold increases in potency, 700-fold higher antibody titers, 400-fold higher cellular responses to a model antigen, and improved treatment of mice with lymphomas. IR-SNAs exhibit up to eightfold increases in potency and 30% greater reduction in fibrosis score in mice with nonalcoholic steatohepatitis (NASH). Given the clinical potential of SNAs due to their potency, defined chemical nature, and good tolerability, SNAs are attractive new modalities for developing immunotherapies. PMID:25775582

  16. Perfluorooctanoic acid and environmental risks

    EPA Science Inventory

    Perfluorooctanoic acid (PFOA) is a member of the perfluoroalkyl acids (PFAA) family of chemicals, which consist of a carbon backbone typically four to fourteen carbons in length and a charged functional moiety.

  17. Folic Acid Questions and Answers

    MedlinePlus

    ... swallow large pills. How can I take a vitamin with folic acid? A : These days, multivitamins with folic acid come in chewable chocolate or fruit flavors, liquids, and large oval or smaller round ...

  18. Omega-3 fatty acids (image)

    MedlinePlus

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

  19. Acid rain: Reign of controversy

    SciTech Connect

    Kahan, A.M.

    1986-01-01

    Acid Rain is a primer on the science and politics of acid rain. Several introductory chapters describe in simple terms the relevant principles of water chemistry, soil chemistry, and plant physiology and discuss the demonstrated or postulated effects of acid rain on fresh waters and forests as well as on statuary and other exposed objects. There follow discussions on the economic and social implications of acid rain (for example, possible health effects) and on the sources, transport, and distribution of air pollutants.

  20. Sedimentation of sulfuric acid in acid tars from current production

    SciTech Connect

    Denisova, T.L.; Frolov, A.F.; Aminov, A.N.; Novosel'tsev, S.P.

    1987-09-01

    Acid tars obtained in treating T-750, KhF-12, and I-8A oils were investigated for purposes of recovering sulfuric acid and asphalt binders from the compositions and of determining the effects of storage time on the recovery. The consumption and sedimentation levels of sulfuric acid during storage for different periods and at different temperatures were assessed. The characteristics of an asphalt binder obtained by neutralizing acid tar with a paste consisting of asphalts from deasphalting operations and slaked lime, followed by oxidation of the mixture with atmospheric air, were determined. The sulfuric acid recovered in the settling process could be burned in order to purify it of organic contaminants.

  1. Sequential injection redox or acid-base titration for determination of ascorbic acid or acetic acid.

    PubMed

    Lenghor, Narong; Jakmunee, Jaroon; Vilen, Michael; Sara, Rolf; Christian, Gary D; Grudpan, Kate

    2002-12-01

    Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to 1200 mg l(-1) was achieved. The relative standard deviation for 11 replicate determinations of 400 mg l(-1) ascorbic acid was 2.9%. The second system, for acetic acid determination, was based on acid-base titration of acetic acid with sodium hydroxide using phenolphthalein as an indicator. The decrease in color intensity of the indicator was proportional to the acid content. A linear calibration graph in the range of 2-8% w v(-1) of acetic acid with a relative standard deviation of 4.8% (5.0% w v(-1) acetic acid, n=11) was obtained. Sample throughputs of 60 h(-1) were achieved for both systems. The systems were successfully applied for the assays of ascorbic acid in vitamin C tablets and acetic acid content in vinegars, respectively.

  2. A system dynamics model integrating physiology and biochemical regulation predicts extent of crassulacean acid metabolism (CAM) phases.

    PubMed

    Owen, Nick A; Griffiths, Howard

    2013-12-01

    A system dynamics (SD) approach was taken to model crassulacean acid metabolism (CAM) expression from measured biochemical and physiological constants. SD emphasizes state-dependent feedback interaction to describe the emergent properties of a complex system. These mechanisms maintain biological systems with homeostatic limits on a temporal basis. Previous empirical studies on CAM have correlated biological constants (e.g. enzyme kinetic parameters) with expression over the CAM diel cycle. The SD model integrates these constants within the architecture of the CAM 'system'. This allowed quantitative causal connections to be established between biological inputs and the four distinct phases of CAM delineated by gas exchange and malic acid accumulation traits. Regulation at flow junctions (e.g. stomatal and mesophyll conductance, and malic acid transport across the tonoplast) that are subject to feedback control (e.g. stomatal aperture, malic acid inhibition of phosphoenolpyruvate carboxylase, and enzyme kinetics) was simulated. Simulated expression for the leaf-succulent Kalanchoë daigremontiana and more succulent tissues of Agave tequilana showed strong correlation with measured gas exchange and malic acid accumulation (R(2)  = 0.912 and 0.937, respectively, for K. daigremontiana and R(2)  = 0.928 and 0.942, respectively, for A. tequilana). Sensitivity analyses were conducted to quantitatively identify determinants of diel CO2 uptake. The transition in CAM expression from low to high volume/area tissues (elimination of phase II-IV carbon-uptake signatures) was achieved largely by the manipulation three input parameters. PMID:23992169

  3. A system dynamics model integrating physiology and biochemical regulation predicts extent of crassulacean acid metabolism (CAM) phases.

    PubMed

    Owen, Nick A; Griffiths, Howard

    2013-12-01

    A system dynamics (SD) approach was taken to model crassulacean acid metabolism (CAM) expression from measured biochemical and physiological constants. SD emphasizes state-dependent feedback interaction to describe the emergent properties of a complex system. These mechanisms maintain biological systems with homeostatic limits on a temporal basis. Previous empirical studies on CAM have correlated biological constants (e.g. enzyme kinetic parameters) with expression over the CAM diel cycle. The SD model integrates these constants within the architecture of the CAM 'system'. This allowed quantitative causal connections to be established between biological inputs and the four distinct phases of CAM delineated by gas exchange and malic acid accumulation traits. Regulation at flow junctions (e.g. stomatal and mesophyll conductance, and malic acid transport across the tonoplast) that are subject to feedback control (e.g. stomatal aperture, malic acid inhibition of phosphoenolpyruvate carboxylase, and enzyme kinetics) was simulated. Simulated expression for the leaf-succulent Kalanchoë daigremontiana and more succulent tissues of Agave tequilana showed strong correlation with measured gas exchange and malic acid accumulation (R(2)  = 0.912 and 0.937, respectively, for K. daigremontiana and R(2)  = 0.928 and 0.942, respectively, for A. tequilana). Sensitivity analyses were conducted to quantitatively identify determinants of diel CO2 uptake. The transition in CAM expression from low to high volume/area tissues (elimination of phase II-IV carbon-uptake signatures) was achieved largely by the manipulation three input parameters.

  4. Nervonic acid and demyelinating disease.

    PubMed

    Sargent, J R; Coupland, K; Wilson, R

    1994-04-01

    Demyelination in adrenoleukodystrophy (ALD) is associated with an accumulation of very long chain saturated fatty acids such as 26:0 stemming from a genetic defect in the peroxisomal beta oxidation system responsible for the chain shortening of these fatty acids. Long chain monoenoic acids such as erucic acid, 22:1(n-9), can normalise elevated serum levels of 26:0 in ALD by depressing their biosynthesis from shorter chain saturated fatty acids. Sphingolipids from post mortem ALD brain have decreased levels of nervonic acid, 24:1(n-9), and increased levels of stearic acid, 18:0. Increased levels of 26:0 are accompanied by decreased nervonic acid biosynthesis in skin fibroblasts from ALD patients. Sphingolipids from post mortem MS brain have the same decreased 24:1(n-9) and increased 18:0 seen in post mortem ALD brain. The 24:1(n-9) content of sphingomyelin is depressed in erythrocytes from multiple sclerosis (MS) patients. Defects in the microsomal biosynthesis of very long chain fatty acids including 24:1(n-9) in 'jumpy' and 'quaking' mice are accompanied by impaired myelination. An impairment in the provision of nervonic acid in demyelinating diseases is indicated, suggesting that dietary therapy with oils rich in very long chain monenoic acid fatty acids may be beneficial in such conditions.

  5. Pantothenic acid biosynthesis in zymomonas

    SciTech Connect

    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.

  6. An Umbrella for Acid Rain.

    ERIC Educational Resources Information Center

    Randal, Judith

    1979-01-01

    The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

  7. Carboxylic acid sorption regeneration process

    DOEpatents

    King, C.J.; Poole, L.J.

    1995-05-02

    Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine. 10 figs.

  8. Carboxylic acid sorption regeneration process

    DOEpatents

    King, C. Judson; Poole, Loree J.

    1995-01-01

    Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine.

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

    PubMed

    Liu, Yongchun; Ma, Qingxin; He, Hong

    2012-10-16

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

  10. [Effect of phosphate and organic acid addition on passivation of simulated Pb contaminated soil and the stability of the product].

    PubMed

    Zuo, Ji-Chao; Gao, Ting-Ting; Su, Xiao-Juan; Wan, Tian-Ying; Hu, Hong-Qing

    2014-10-01

    Organic acids can improve the phosphorus availability, influence the immobilization of heavy metals in soil, and has very complicated function in phosphorus activation and heavy metal passivation. This research took simulated Pb contaminated soil as material, phosphate and citric acid as remediation matter, adopted BCR continuous extraction, 0.01 mol · L(-1) CaCl2 and toxicity characteristic leaching procedure (TCLP) to evaluate the remediation effect. Besides, malic acid and NaNO3 were taken as desorption reagents to discuss the stability of the phosphorus-citric acid-Pb system. The results showed that: in the absence of citric acid, the amount of acid extracted Pb decreased along with the increase of P concentration; when the P concentration was 100 and 400 mg · kg(-1), acid extractable Pb increased with the increasing of citric acid concentration. However, residual Pb changed in the opposite direction from acid extractable Pb. The phenomenon showed that P improved the bioavailability of Pb, while citric acid had the opposite effect. With a certain organic acid concentration, extractable Pb contents extracted by 0.01 mol · L(-1) CaCl2 and TCLP both decreased with the increasing P concentration, therefore, P had immobilization effect on Pb in contaminated soil. But at a fixed P concentration, extractable Pb contents by 0.01 mol · L(-1) CaCl2 and TCLP changed in the opposite trend with the increasing citric acid concentration. The desorption rate of Pb in soil increased with the increasing malic acid concentration, the decreasing pH and the increasing ionic strength. The desorption extent of Pb in soil with P only was lower than that with both P and citric acid. But the stability of Pb passivated by the former was higher. PMID:25693396

  11. [Effect of phosphate and organic acid addition on passivation of simulated Pb contaminated soil and the stability of the product].

    PubMed

    Zuo, Ji-Chao; Gao, Ting-Ting; Su, Xiao-Juan; Wan, Tian-Ying; Hu, Hong-Qing

    2014-10-01

    Organic acids can improve the phosphorus availability, influence the immobilization of heavy metals in soil, and has very complicated function in phosphorus activation and heavy metal passivation. This research took simulated Pb contaminated soil as material, phosphate and citric acid as remediation matter, adopted BCR continuous extraction, 0.01 mol · L(-1) CaCl2 and toxicity characteristic leaching procedure (TCLP) to evaluate the remediation effect. Besides, malic acid and NaNO3 were taken as desorption reagents to discuss the stability of the phosphorus-citric acid-Pb system. The results showed that: in the absence of citric acid, the amount of acid extracted Pb decreased along with the increase of P concentration; when the P concentration was 100 and 400 mg · kg(-1), acid extractable Pb increased with the increasing of citric acid concentration. However, residual Pb changed in the opposite direction from acid extractable Pb. The phenomenon showed that P improved the bioavailability of Pb, while citric acid had the opposite effect. With a certain organic acid concentration, extractable Pb contents extracted by 0.01 mol · L(-1) CaCl2 and TCLP both decreased with the increasing P concentration, therefore, P had immobilization effect on Pb in contaminated soil. But at a fixed P concentration, extractable Pb contents by 0.01 mol · L(-1) CaCl2 and TCLP changed in the opposite trend with the increasing citric acid concentration. The desorption rate of Pb in soil increased with the increasing malic acid concentration, the decreasing pH and the increasing ionic strength. The desorption extent of Pb in soil with P only was lower than that with both P and citric acid. But the stability of Pb passivated by the former was higher.

  12. Composition for nucleic acid sequencing

    SciTech Connect

    Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

    2008-08-26

    The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

  13. Evolution of rosmarinic acid biosynthesis.

    PubMed

    Petersen, Maike; Abdullah, Yana; Benner, Johannes; Eberle, David; Gehlen, Katja; Hücherig, Stephanie; Janiak, Verena; Kim, Kyung Hee; Sander, Marion; Weitzel, Corinna; Wolters, Stefan

    2009-01-01

    Rosmarinic acid and chlorogenic acid are caffeic acid esters widely found in the plant kingdom and presumably accumulated as defense compounds. In a survey, more than 240 plant species have been screened for the presence of rosmarinic and chlorogenic acids. Several rosmarinic acid-containing species have been detected. The rosmarinic acid accumulation in species of the Marantaceae has not been known before. Rosmarinic acid is found in hornworts, in the fern family Blechnaceae and in species of several orders of mono- and dicotyledonous angiosperms. The biosyntheses of caffeoylshikimate, chlorogenic acid and rosmarinic acid use 4-coumaroyl-CoA from the general phenylpropanoid pathway as hydroxycinnamoyl donor. The hydroxycinnamoyl acceptor substrate comes from the shikimate pathway: shikimic acid, quinic acid and hydroxyphenyllactic acid derived from l-tyrosine. Similar steps are involved in the biosyntheses of rosmarinic, chlorogenic and caffeoylshikimic acids: the transfer of the 4-coumaroyl moiety to an acceptor molecule by a hydroxycinnamoyltransferase from the BAHD acyltransferase family and the meta-hydroxylation of the 4-coumaroyl moiety in the ester by a cytochrome P450 monooxygenase from the CYP98A family. The hydroxycinnamoyltransferases as well as the meta-hydroxylases show high sequence similarities and thus seem to be closely related. The hydroxycinnamoyltransferase and CYP98A14 from Coleus blumei (Lamiaceae) are nevertheless specific for substrates involved in RA biosynthesis showing an evolutionary diversification in phenolic ester metabolism. Our current view is that only a few enzymes had to be "invented" for rosmarinic acid biosynthesis probably on the basis of genes needed for the formation of chlorogenic and caffeoylshikimic acid while further biosynthetic steps might have been recruited from phenylpropanoid metabolism, tocopherol/plastoquinone biosynthesis and photorespiration. PMID:19560175

  14. Evolution of rosmarinic acid biosynthesis.

    PubMed

    Petersen, Maike; Abdullah, Yana; Benner, Johannes; Eberle, David; Gehlen, Katja; Hücherig, Stephanie; Janiak, Verena; Kim, Kyung Hee; Sander, Marion; Weitzel, Corinna; Wolters, Stefan

    2009-01-01

    Rosmarinic acid and chlorogenic acid are caffeic acid esters widely found in the plant kingdom and presumably accumulated as defense compounds. In a survey, more than 240 plant species have been screened for the presence of rosmarinic and chlorogenic acids. Several rosmarinic acid-containing species have been detected. The rosmarinic acid accumulation in species of the Marantaceae has not been known before. Rosmarinic acid is found in hornworts, in the fern family Blechnaceae and in species of several orders of mono- and dicotyledonous angiosperms. The biosyntheses of caffeoylshikimate, chlorogenic acid and rosmarinic acid use 4-coumaroyl-CoA from the general phenylpropanoid pathway as hydroxycinnamoyl donor. The hydroxycinnamoyl acceptor substrate comes from the shikimate pathway: shikimic acid, quinic acid and hydroxyphenyllactic acid derived from l-tyrosine. Similar steps are involved in the biosyntheses of rosmarinic, chlorogenic and caffeoylshikimic acids: the transfer of the 4-coumaroyl moiety to an acceptor molecule by a hydroxycinnamoyltransferase from the BAHD acyltransferase family and the meta-hydroxylation of the 4-coumaroyl moiety in the ester by a cytochrome P450 monooxygenase from the CYP98A family. The hydroxycinnamoyltransferases as well as the meta-hydroxylases show high sequence similarities and thus seem to be closely related. The hydroxycinnamoyltransferase and CYP98A14 from Coleus blumei (Lamiaceae) are nevertheless specific for substrates involved in RA biosynthesis showing an evolutionary diversification in phenolic ester metabolism. Our current view is that only a few enzymes had to be "invented" for rosmarinic acid biosynthesis probably on the basis of genes needed for the formation of chlorogenic and caffeoylshikimic acid while further biosynthetic steps might have been recruited from phenylpropanoid metabolism, tocopherol/plastoquinone biosynthesis and photorespiration.

  15. Effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids in the juice sacs of Satsuma mandarin (Citrus unshiu Marc.) fruit.

    PubMed

    Matsumoto, Hikaru; Ikoma, Yoshinori

    2012-10-01

    To elucidate the effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids and to determine the best temperature to minimize their postharvest change, their content after harvest was investigated at 5, 10, 20, and 30 °C for 14 days in the juice sacs of Satsuma mandarin (Citrus unshiu Marc. cv. Aoshima-unshiu) fruit. In all sugars, the changes were negligible at all temperatures. Organic acids decreased slightly at all temperatures, with the exception of malic acid at 30 °C, which increased slightly. Two amino acids, ornithine and glutamine, increased at 5 °C, but they did not increase at other temperatures. In 11 amino acids (phenylalanine, tryptophan, tyrosine, isoleucine, leucine, valine, threonine, lysine, methionine, histidine, and γ-amino butyric acid), the content was higher at 20 and 30 °C than at other temperatures. Thus, the content of amino acids was more variable than that of sugars and organic acids in response to temperatures. Moreover, amino acids responded to temperature differently: two amino acids were cold responsive, and 11 were heat-responsive. The best temperature to minimize the postharvest changes in amino acid profiles in the juice sacs of Aoshima-unshiu was 10 °C. The responsiveness to temperatures in two cold-responsive (ornithine and glutamine) and five heat-responsive (phenylalanine, tryptophan, valine, lysine, and histidine) amino acids was conserved among three different Satsuma mandarin cultivars, Aoshima-unshiu (late-maturing cultivar), Silverhill (midmaturing cultivar), and Miyagawa-wase (early-maturing cultivar). The metabolic responsiveness to temperature stress was discussed on the basis of the changes in the amino acid profile.

  16. Microbial transformations of isocupressic acid.

    PubMed

    Lin, S J; Rosazza, J P

    1998-07-01

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

  17. Invasive cleavage of nucleic acids

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    2002-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  18. Invasive cleavage of nucleic acids

    DOEpatents

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    1999-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  19. The politics of acid rain

    SciTech Connect

    Wilcher, M.E. )

    1989-01-01

    This work examines and compares the acid rain policies through the different political systems of Canada, Great Britain and the United States. Because the flow of acid rain can transcend national boundaries, acid rain has become a crucial international problem. According to the author, because of differences in governmental institutions and structure, the extent of governmental intervention in the industrial economy, the degree of reliance on coal for power generation, and the extent of acid rain damage, national responses to the acid rain problem have varied.

  20. [A catalogue of fatty acids].

    PubMed

    Canalejo, E; Martín Peña, G; Gómez Molero, L; Ruiz Galiana, J

    1996-01-01

    Fatty acids structure and function is an area of renewed interest because of its effects on plasma lipids, biosynthesis of prostaglandins, leucotrienes and thromboxanes, and the obligatory demands of some fatty acids, especially for the newborn. Fatty acids are identified in three different ways: by the classical nomenclature, by its trivial name, and by the new methods also known as the omega system. These three different methods have created some confusion. The aim of this article is to revise fatty acids chemical structure and to compile a list of nutritional important fatty acids with the three different terminologies.

  1. A Thermostable Salmonella Phage Endolysin, Lys68, with Broad Bactericidal Properties against Gram-Negative Pathogens in Presence of Weak Acids

    PubMed Central

    Oliveira, Hugo; Thiagarajan, Viruthachalam; Walmagh, Maarten; Sillankorva, Sanna; Lavigne, Rob; Neves-Petersen, Maria Teresa; Kluskens, Leon D.; Azeredo, Joana

    2014-01-01

    Resistance rates are increasing among several problematic Gram-negative pathogens, a fact that has encouraged the development of new antimicrobial agents. This paper characterizes a Salmonella phage endolysin (Lys68) and demonstrates its potential antimicrobial effectiveness when combined with organic acids towards Gram-negative pathogens. Biochemical characterization reveals that Lys68 is more active at pH 7.0, maintaining 76.7% of its activity when stored at 4°C for two months. Thermostability tests showed that Lys68 is only completely inactivated upon exposure to 100°C for 30 min, and circular dichroism analysis demonstrated the ability to refold into its original conformation upon thermal denaturation. It was shown that Lys68 is able to lyse a wide panel of Gram-negative bacteria (13 different species) in combination with the outer membrane permeabilizers EDTA, citric and malic acid. While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively). Particularly against Salmonella Typhimurium LT2, the combinatory effect of malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained by the destabilization and major disruptions of the cell outer membrane integrity due to the acidity caused by the organic acids and a relatively high muralytic activity of Lys68 at low pH. Lys68 demonstrates good (thermo)stability properties that combined with different outer membrane permeabilizers, could become useful to combat Gram-negative pathogens in agricultural, food and medical industry. PMID:25290100

  2. Tested Demonstrations: Color Oscillations in the Formic Acid-Nitric Acid-Sulfuric Acid System.

    ERIC Educational Resources Information Center

    Raw, C. J. G.; And Others

    1983-01-01

    Presented are procedures for demonstrating the production of color oscillations when nitric acid is added to a formic acid/concentrated sulfuric acid mixture. Because of safety considerations, "Super-8" home movie of the color changes was found to be satisfactory for demonstration purposes. (JN)

  3. Fatty acid biosynthesis during the life cycle of Debaryomyces etchellsii.

    PubMed

    Arous, Fatma; Mechichi, Tahar; Nasri, Moncef; Aggelis, George

    2016-07-01

    Fatty acid biosynthesis during the life cycle of the ascomycetous yeast Debaryomyces etchellsii cultivated on a non-fermentable substrate, i.e. glycerol, in nitrogen rich media (NRM) and nitrogen limited media (NLM) has been studied. Although considerable activities of key lipogenic enzymes, such as ATP citrate lyase (ACL) and malic enzyme (ME), were detected in vegetative cells during asexual proliferation (which occurred in the first growth stages in both NRM and NLM), lipid accumulation was restricted due to the high activities of NAD+-isocitrate dehydrogenase (NAD+-ICDH). A similar enzymatic profile has been found in ascii and free ascospores produced in NRM; thus lipid accumulation was low. On the contrary, very high activities of both ACL and ME and low activities of NAD+-ICDH were detected in ascii and free ascospores produced in NLM resulting in lipid accumulation. Neutral lipids (NL) were the predominant fraction of cellular lipids produced in vegetative cells and ascospores in both NRM and NLM. On the other hand, phospholipids (P) were the major polar lipids while glycolipids (G) were synthesized in low proportions. During transition from asexual to sexual phase, the percentage of NL increased with a significant decrease of P and, to a lesser extent, of G. High quantities of linoleic acid were found esterified in polar lipids, especially in P, during the vegetative stage of growth, while, with a few exceptions, during transition from asexual to sexual stage, linoleic acid concentration decreased markedly, mainly in P, while oleic acid concentration increased. PMID:27129978

  4. Twinning of dodecanedicarboxylic acid

    NASA Technical Reports Server (NTRS)

    Sen, R.; Wilcox, W. R.

    1986-01-01

    Twinning of 1,10-dodecanedicarboxyl acid (DDA) was observed in 0.1 mm thick films with a polarizing microscope. Twins originated from polycrystalline regions which tended to nucleate on twin faces, and terminated by intersection gone another. Twinning increased dramatically with addition of organic compounds with a similar molecular size and shape. Increasing the freezing rate, increasing the temperature gradient, and addition of silica particles increased twinning. It is proposed that twins nucleate with polycrystals and sometimes anneal out before they become observable. The impurities may enhance twinning either by lowering the twin energy or by adsorbing on growing faces.

  5. Mycophenolic Acid in Silage

    PubMed Central

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

    2000-01-01

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

  6. Synthesis of amino acids

    DOEpatents

    Davis, J.W. Jr.

    1979-09-21

    A method is described for synthesizing amino acids preceding through novel intermediates of the formulas: R/sub 1/R/sub 2/C(OSOC1)CN, R/sub 1/R/sub 2/C(C1)CN and (R/sub 1/R/sub 2/C(CN)O)/sub 2/SO wherein R/sub 1/ and R/sub 2/ are each selected from hydrogen and monovalent hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

  7. Beyond acid rain

    SciTech Connect

    Gaffney, J.S.; Streit, G.E.; Spall, W.D.; Hall, J.H.

    1987-06-01

    This paper discussed the effects of the interactions of soluble oxidants and organic toxins with sulfur dioxide and nitrogen dioxide. It suggested that these chemical reactions in the atmosphere produced a more potent acid rain which was harmful not only because it had a low pH but because it contained oxidants and organic toxins which were harmful to surface vegetation and the organisms found in surface waters. It was stressed that air pollution is a global problem and that is is necessary to develop a better fundamental understanding of how air pollution is causing damage to the streams and forests of the world. 50 references.

  8. Interstellar isothiocyanic acid

    NASA Technical Reports Server (NTRS)

    Frerking, M. A.; Linke, R. A.; Thaddeus, P.

    1979-01-01

    Isothiocyanic acid (HNCS) has been identified in Sgr B2 from millimeter-wave spectral line observations. We have definitely detected three rotational lines, and have probably detected two others. The rotational temperature of HNCS in Sgr B2 is 14 plus or minus 5 K, its column density is 2.5 plus or minus 1.0 x 10 to the 13th per sq cm, and its abundance relative to HNCO is consistent with the cosmic S/O ratio, 1/42.

  9. 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids and blood pressure.

    PubMed

    McGiff, J C; Quilley, J

    2001-03-01

    The properties of 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids, vasoactivity and modulation of ion transport and mediation/modulation of the effects of vasoactive hormones, such as angiotensin II and endothelin, underscore their importance to renal vascular mechanisms and electrolyte excretion. 20-Hydroxyeicosatetraenoic acid is an integral component of renal autoregulation and tubuloglomerular feedback as well as cerebral autoregulation, eliciting vasoconstriction by the inhibition of potassium channels. Nitric oxide inhibits 20-hydroxyeicosatetraenoic acid formation, the removal of which contributes to the vasodilator effect of nitric oxide. In contrast, epoxyeicosatrienoic acids are generally vasodilatory by activating potassium channels and have been proposed as endothelium-derived hyperpolarizing factors. 20-Hydroxyeicosatetraenoic acid modulates ion transport in key nephron segments by influencing the activities of sodium--potassium-ATPase and the sodium--potassium--chloride co-transporter; however, the primacy of the various arachidonate oxygenases that generate products affecting these activities changes with age. The range and diversity of activity of 20-hydroxyeicosatetraenoic acid is influenced by its metabolism by cyclooxygenase to products affecting vasomotion and salt/water excretion. 20-Hydroxyeicosatetraenoic acid is the principal renal eicosanoid that interacts with several hormonal systems that are central to blood pressure regulation. This article reviews the most recent studies that address 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids in vascular and renal tubular function and hypertension.

  10. Negligible penetration of incidental amounts of alpha-hydroxy acid from rinse-off personal care products in human skin using an in vitro static diffusion cell model.

    PubMed

    Okuda, M; Donahue, D A; Kaufman, L E; Avalos, J; Simion, F A; Story, D C; Sakaguchi, H; Fautz, R; Fuchs, A

    2011-12-01

    Alpha-hydroxy acids (AHAs), primarily glycolic and lactic acids, are widely used in cosmetics to alleviate dyspigmentation, photodamage, and other aging skin conditions and as pH adjusters. Glycolic acid reportedly enhances skin damage after repeated ultraviolet light exposure, e.g., increased sunburn cell formation. This study assessed potential in vitro skin penetration of lactic acid and malic acid incorporated into rinse-off personal care products, compared with rinse-off and leave-on exposures to glycolic acid (10%, pH 3.5) in a reference lotion. Radiolabeled AHA-fortified shampoo, conditioner, and lotion were evenly applied as single doses to human epidermal membranes mounted in static diffusion cells (not occluded). Exposures were 1-3 min (rinse-off) or 24 h (leave-on). Epidermal penetration of malic acid and lactic acid from the rinse-off shampoo and conditioner, respectively, was negligible, with >99% removed by rinsing, a negligible portion remaining in the stratum corneum (≤0.15%), and even less penetrating into the viable epidermis (≤0.04%). Glycolic acid penetration from the leave-on reference lotion was 1.42 μg equiv./cm2/h, with total absorbable dose recovery (receptor fluid plus epidermis) of 2.51%, compared to 0.009%, 0.003%, and 0.04% for the rinse-off reference lotion, shampoo (malic acid), and conditioner (lactic acid) exposures, respectively. Dermal penetration of AHAs into human skin is pH-, concentration-, and time-dependent. Alpha-hydroxy acids in rinse-off shampoos and conditioners are almost entirely removed from the skin within minutes by rinsing (resulting in negligible epidermal penetration). This suggests that ultraviolet radiation-induced skin effects of AHA-containing rinse-off products are negligible. PMID:21871557

  11. Negligible penetration of incidental amounts of alpha-hydroxy acid from rinse-off personal care products in human skin using an in vitro static diffusion cell model.

    PubMed

    Okuda, M; Donahue, D A; Kaufman, L E; Avalos, J; Simion, F A; Story, D C; Sakaguchi, H; Fautz, R; Fuchs, A

    2011-12-01

    Alpha-hydroxy acids (AHAs), primarily glycolic and lactic acids, are widely used in cosmetics to alleviate dyspigmentation, photodamage, and other aging skin conditions and as pH adjusters. Glycolic acid reportedly enhances skin damage after repeated ultraviolet light exposure, e.g., increased sunburn cell formation. This study assessed potential in vitro skin penetration of lactic acid and malic acid incorporated into rinse-off personal care products, compared with rinse-off and leave-on exposures to glycolic acid (10%, pH 3.5) in a reference lotion. Radiolabeled AHA-fortified shampoo, conditioner, and lotion were evenly applied as single doses to human epidermal membranes mounted in static diffusion cells (not occluded). Exposures were 1-3 min (rinse-off) or 24 h (leave-on). Epidermal penetration of malic acid and lactic acid from the rinse-off shampoo and conditioner, respectively, was negligible, with >99% removed by rinsing, a negligible portion remaining in the stratum corneum (≤0.15%), and even less penetrating into the viable epidermis (≤0.04%). Glycolic acid penetration from the leave-on reference lotion was 1.42 μg equiv./cm2/h, with total absorbable dose recovery (receptor fluid plus epidermis) of 2.51%, compared to 0.009%, 0.003%, and 0.04% for the rinse-off reference lotion, shampoo (malic acid), and conditioner (lactic acid) exposures, respectively. Dermal penetration of AHAs into human skin is pH-, concentration-, and time-dependent. Alpha-hydroxy acids in rinse-off shampoos and conditioners are almost entirely removed from the skin within minutes by rinsing (resulting in negligible epidermal penetration). This suggests that ultraviolet radiation-induced skin effects of AHA-containing rinse-off products are negligible.

  12. Phenolic and short-chained aliphatic organic acid constituents of wild oat (Avena fatua L.) seeds.

    PubMed

    Gallagher, R S; Ananth, R; Granger, K; Bradley, B; Anderson, J V; Fuerst, E P

    2010-01-13

    The objective of this research was to identify and quantify the phenolic and short-chained aliphatic organic acids present in the seeds of three wild-type populations of wild oat and compare these results to the chemical composition of seeds from two commonly utilized wild oat isolines (M73 and SH430). Phenolic acids have been shown to serve as germination inhibitors, as well as protection for seeds from biotic and abiotic stress factors in other species, whereas aliphatic organic acids have been linked to germination traits and protection against pathogens. Wild oat populations were grown under a "common garden" environment to remove maternal variation, and the resulting seeds were extracted to remove the readily soluble and chemically bound phenolic and aliphatic organic acid components. Compounds were identified and quantified using gas chromatography-mass spectrometry. Ferulic and p-coumaric acid comprised 99% of the total phenolic acids present in the seeds, of which 91% were contained in the hulls and 98% were in the chemically bound forms. Smaller quantities of OH benzoic and vanillic acid were also detected. Soluble organic acids concentrations were higher in the M73 isoline compared to SH430, suggesting that these chemical constituents could be related to seed dormancy. Malic, succinic, fumaric and azelaic acid were the dominant aliphatic organic acids detected in all seed and chemical fractions.

  13. Vibrational structure of the polyunsaturated fatty acids eicosapentaenoic acid and arachidonic acid studied by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Kiefer, Johannes; Noack, Kristina; Bartelmess, Juergen; Walter, Christian; Dörnenburg, Heike; Leipertz, Alfred

    2010-02-01

    The spectroscopic discrimination of the two structurally similar polyunsaturated C 20 fatty acids (PUFAs) 5,8,11,14,17-eicosapentaenoic acid and 5,8,11,14-eicosatetraenoic acid (arachidonic acid) is shown. For this purpose their vibrational structures are studied by means of attenuated total reflection (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The fingerprint regions of the recorded spectra are found to be almost identical, while the C-H stretching mode regions around 3000 cm -1 show such significant differences as results of electronic and molecular structure alterations based on the different degree of saturation that both fatty acids can be clearly distinguished from each other.

  14. Nucleic acid detection methods

    DOEpatents

    Smith, C.L.; Yaar, R.; Szafranski, P.; Cantor, C.R.

    1998-05-19

    The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3{prime}-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated. 18 figs.

  15. Nucleic Acid Detection Methods

    DOEpatents

    Smith, Cassandra L.; Yaar, Ron; Szafranski, Przemyslaw; Cantor, Charles R.

    1998-05-19

    The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3'-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated.

  16. Cryoprotection from lipoteichoic acid

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  17. Bicyclic glutamic acid derivatives.

    PubMed

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

    2006-05-15

    For the second-generation asymmetric synthesis of the trans-tris(homoglutamic) acids via Strecker reaction of chiral ketimines, the cyanide addition as the key stereodifferentiating step produces mixtures of diastereomeric alpha-amino nitrile esters the composition of which is independent of the reaction temperature and the type of the solvent, respectively. The subsequent hydrolysis is exclusively achieved with concentrated H(2)SO(4) yielding diastereomeric mixtures of three secondary alpha-amino alpha-carbamoyl-gamma-esters and two diastereomeric cis-fused angular alpha-carbamoyl gamma-lactams as bicyclic glutamic acid derivatives, gained from in situ stereomer differentiating cyclisation of the secondary cis-alpha-amino alpha-carbamoyl-gamma-esters. Separation was achieved by CC. The pure secondary trans-alpha-amino alpha-carbamoyl-gamma-esters cyclise on heating and treatment with concentrated H(2)SO(4), respectively, to diastereomeric cis-fused angular secondary alpha-amino imides. Their hydrogenolysis led to the enantiomeric cis-fused angular primary alpha-amino imides. The configuration of all compounds was completely established by NMR methods, CD-spectra, and by X-ray analyses of the (alphaR,1R,5R)-1-carbamoyl-2-(1-phenylethyl)-2-azabicyclo[3.3.0]octan-3-one and of the trans-alphaS,1S,2R-2-ethoxycarbonylmethyl-1-(1-phenylethylamino)cyclopentanecarboxamide. PMID:16596563

  18. Ribonucleic acid purification.

    PubMed

    Martins, R; Queiroz, J A; Sousa, F

    2014-08-15

    Research on RNA has led to many important biological discoveries and improvement of therapeutic technologies. From basic to applied research, many procedures employ pure and intact RNA molecules; however their isolation and purification are critical steps because of the easy degradability of RNA, which can impair chemical stability and biological functionality. The current techniques to isolate and purify RNA molecules still have several limitations and the requirement for new methods able to improve RNA quality to meet regulatory demands is growing. In fact, as basic research improves the understanding of biological roles of RNAs, the biopharmaceutical industry starts to focus on them as a biotherapeutic tools. Chromatographic bioseparation is a high selective unit operation and is the major option in the purification of biological compounds, requiring high purity degree. In addition, its application in biopharmaceutical manufacturing is well established. This paper discusses the importance and the progress of RNA isolation and purification, considering RNA applicability both in research and clinical fields. In particular and in view of the high specificity, affinity chromatography has been recently applied to RNA purification processes. Accordingly, recent chromatographic investigations based on biorecognition phenomena occurring between RNA and amino acids are focused. Histidine and arginine have been used as amino acid ligands, and their ability to isolate different RNA species demonstrated a multipurpose applicability in molecular biology analysis and RNA therapeutics preparation, highlighting the potential contribution of these methods to overcome the challenges of RNA purification. PMID:24951289

  19. Modulation of organic acids and sugar content in tomato fruits by an abscisic acid-regulated transcription factor.

    PubMed

    Bastías, Adriana; López-Climent, María; Valcárcel, Mercedes; Rosello, Salvador; Gómez-Cadenas, Aurelio; Casaretto, José A

    2011-03-01

    Growing evidence suggests that the phytohormone abscisic acid (ABA) plays a role in fruit development. ABA signaling components of developmental programs and responses to stress conditions include the group of basic leucine zipper transcriptional activators known as ABA-response element binding factors (AREBs/ABFs). AREB transcription factors mediate ABA-regulated gene expression involved in desiccation tolerance and are expressed mainly in seeds and in vegetative tissues under stress; however, they are also expressed in some fruits such as tomato. In order to get an insight into the role of ABA signaling in fruit development, the expression of two AREB-like factors were investigated during different developmental stages. In addition, tomato transgenic lines that overexpress and downregulate one AREB-like transcription factor, SlAREB1, were used to determine its effect on the levels of some metabolites determining fruit quality. Higher levels of citric acid, malic acid, glutamic acid, glucose and fructose were observed in SlAREB1-overexpressing lines compared with those in antisense suppression lines in red mature fruit pericarp. The higher hexose concentration correlated with increased expression of genes encoding a vacuolar invertase (EC 3.2.1.26) and a sucrose synthase (EC 2.4.1.13). No significant changes were found in ethylene content which agrees with the normal ripening phenotype observed in transgenic fruits. These results suggest that an AREB-mediated ABA signal affects the metabolism of these compounds during the fruit developmental program.

  20. Monitoring of the fermentation media of citric acid by the trimethylsilyl derivatives of the organic acids formed.

    PubMed

    Ghassempour, Alireza; Nojavan, Saeed; Talebpour, Zahra; Amiri, Ali Asghar; Najafi, Nahid Mashkouri

    2004-10-20

    In this approach, a derivatization method is described for monitoring of organic acids in fermentation media without any separation step. The aqueous phase of fermentation media was evaporated and heated in a silylation reagent to form trimethylsilyl (TMS) derivatives. The silylated compounds are analyzed by 29Si nuclear magnetic resonance (29Si NMR) and gas chromatography-mass spectrometry (GC-MS). 29Si NMR can qualitatively monitor the components produced in the Krebs cycle. Quantification of these compounds is investigated by using selected ion monitoring mode of mass spectrometry. In this mode, mass to charge (m/z) values of their [M - 15]+ ions, which are 465, 275, 247, 221, 335, 251, and 313 of TMS derivatives of citric, alpha-ketoglutaric, succinic, fumaric, l-malic, oxaloacetic, and palmitic (as an internal standard), acids, respectively, are used. The limit of detection and the linear working range for derivatized citric acid were found to be 0.1 mg L(-1) and 10-3 x 10(4) mg L(-1). The relative standard deviation of the method for five replicates was 2.1%. The average recovery efficiency for citric acid added to culture media was approximately 97.2%. Quantitative results of GC-MS are compared with those obtained by an ultraviolet-visible method.

  1. Titration of phosphonic acid derivatives in mixtures.

    PubMed

    Wittmann, Z

    1980-01-01

    An analytical procedure is described for the determination of the weak acids phosphonomethyliminodiacetic acid and phosphonomethyliminoacetic acid in their mixtures, and the dissociation constants of phosphonomethyliminoacetic acid are reported.

  2. Growth of nitric acid hydrates on thin sulfuric acid films

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-01-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  3. Determination of benzoic acid, chlorobenzoic acids and chlorendic acid in water

    SciTech Connect

    Dietz, E.A.; Cortellucci, N.J.; Singley, K.F. )

    1993-01-01

    To characterize and conduct treatment studies of a landfill leachate an analysis procedure was required to determine concentrations of benzoic acid, the three isomers of chlorobenzoic acid and chlorendic acid. The title compounds were isolated from acidified (pH 1) water by extraction with methyl t-butyl ether. Analytes were concentrated by back-extracting the ether with 0.1 N sodium hydroxide which was separated and acidified. This solution was analyzed by C[sub 18] reversed-phase HPLC with water/acetonitrile/acetic acid eluent and UV detection at 222 nm. The method has detection limits of 200 [mu]g/L for chlorendic acid and 100 [mu]g/L for benzoic acid and each isomer of chlorobenzoic acid. Validation studies with water which was fortified with the analytes at concentrations ranging from one to ten times detection limits resulted in average recoveries of >95%.

  4. Acid rain: Rhetoric and reality

    SciTech Connect

    Park, C.C.

    1987-01-01

    Acid rain is now one of the most serious environmental problems in developed countries. Emissions and fallout were previously extremely localized, but since the introduction of tall stacks policies in both Britain and the US - pardoxically to disperse particulate pollutants and hence reduce local damage - emissions are now lifted into the upper air currents and carried long distances downwind. The acid rain debate now embraces many western countries - including Canada, the US, England, Scotland, Wales, Sweden, Norway, Denmark, West Germany, the Netherlands, Austria, Switzerland - and a growing number of eastern countries - including the Soviet Union, Poland, East Germany, and Czechoslovakia. The problem of acid rain arises, strictly speaking, not so much from the rainfall itself as from its effects on the environment. Runoff affects surface water and groundwater, as well as soils and vegetation. Consequently changes in rainfall acidity can trigger off a range of impacts on the chemistry and ecology of lakes and rivers, soil chemistry and processes, the health and productivity of plants, and building materials, and metallic structures. The most suitable solutions to the problems of acid rain require prevention rather than cure, and there is broad agreement in both the political scientific communities on the need to reduce emissions of sulfur and nitrogen oxides to the atmosphere. Book divisions discuss: the problem of acid rain, the science of acid rain, the technology of acid rain, and the politics of acid rain, in an effort to evaluate this growing global problem of acid rain.

  5. Therapeutic targeting of bile acids

    PubMed Central

    Gores, Gregory J.

    2015-01-01

    The first objectives of this article are to review the structure, chemistry, and physiology of bile acids and the types of bile acid malabsorption observed in clinical practice. The second major theme addresses the classical or known properties of bile acids, such as the role of bile acid sequestration in the treatment of hyperlipidemia; the use of ursodeoxycholic acid in therapeutics, from traditional oriental medicine to being, until recently, the drug of choice in cholestatic liver diseases; and the potential for normalizing diverse bowel dysfunctions in irritable bowel syndrome, either by sequestering intraluminal bile acids for diarrhea or by delivering more bile acids to the colon to relieve constipation. The final objective addresses novel concepts and therapeutic opportunities such as the interaction of bile acids and the microbiome to control colonic infections, as in Clostridium difficile-associated colitis, and bile acid targeting of the farnesoid X receptor and G protein-coupled bile acid receptor 1 with consequent effects on energy expenditure, fat metabolism, and glycemic control. PMID:26138466

  6. Bile Acid Metabolism and Signaling

    PubMed Central

    Chiang, John Y. L.

    2015-01-01

    Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans. PMID:23897684

  7. Bile acid interactions with cholangiocytes.

    PubMed

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

    2006-06-14

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

  8. Citric acid production patent review.

    PubMed

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

    2008-01-01

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

  9. Bile acid interactions with cholangiocytes

    PubMed Central

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

    2006-01-01

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

  10. [Determination of organic acids in cane vinasse by micellar electrokinetic capillary chromatography with indirect ultraviolet detection].

    PubMed

    Xu, Yuanjin; Xu, Guiping; Wei, Yuanan

    2006-01-01

    Micellar electrokinetic capillary chromatography (MECC) with indirect ultraviolet (UV) detection method for the separation and determination of several organic acids in cane vinasse, including malonic, formic, tartaric, malic, succinic, glutaric, acetic, lactic and glutamic acids, were developed. Electrophoretic conditions were as follows: uncoated fused silica capillary (56 cm/ 64 cm (effective/total length), 50 microm i. d. ), 7.5 mmol/L potassium acid phthalate-1. 5 mmol/L cetyltrimethyl-ammonium bromide (CTAB) at pH = 6.50 as buffer solution, applied voltage -25 kV, temperature 25 degrees C, detection wavelength 300 nm, reference wavelength 210 nm. Good linearities were obtained for nine organic acids, and the detection limits were 0.5 mg/L, 0.3 mg/L, 1.5 mg/L, 1.5 mg/L, 0.3 mg/L, 0.3 mg/L, 0.4 mg/L, 0.4 mg/L, 0.4 mg/L for malonic, formic, tartaric, malic, succinic, glutaric, acetic, lactic and glutamic acid, respectively. The relative standard deviations (RSDs) for migration times and peak areas of nine organic acids within a day were 0.4% - 0.6% and 2.3% - 4.8%, respectively. The corresponding data for five days were 0.5% -0.7% and 3.3% - 5.2%. The recoveries of acid standards were above 93%. The method can be applied to determine the organic acids in cane vinasse with satisfactory results. PMID:16827307

  11. Interactions of amino acids, carboxylic acids, and mineral acids with different quinoline derivatives

    NASA Astrophysics Data System (ADS)

    Kalita, Dipjyoti; Deka, Himangshu; Samanta, Shyam Sundar; Guchait, Subrata; Baruah, Jubaraj B.

    2011-03-01

    A series of quinoline containing receptors having amide and ester bonds are synthesized and characterised. The relative binding abilities of these receptors with various amino acids, carboxylic acids and mineral acids are determined by monitoring the changes in fluorescence intensity. Among the receptors bis(2-(quinolin-8-yloxy)ethyl) isophthalate shows fluorescence enhancement on addition of amino acids whereas the other receptors shows fluorescence quenching on addition of amino acids. The receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy) propanamide has higher binding affinity for amino acids. However, the receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide having similar structure do not bind to amino acids. This is attributed to the concave structure of the former which is favoured due to the presence of methyl substituent. The receptor bis(2-(quinolin-8-yloxy)ethyl) isophthalate do not bind to hydroxy carboxylic acids, but is a good receptor for dicarboxylic acids. The crystal structure of bromide and perchlorate salts of receptor 2-bromo-N-(quinolin-8-yl)-propanamide are determined. In both the cases the amide groups are not in the plane of quinoline ring. The structure of N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide, N-(2-methoxyphenethyl)-2-(quinolin-8-yloxy)acetamide and their salts with maleic acid as well as fumaric acid are determined. It is observed that the solid state structures are governed by the double bond geometry of these two acid. Maleic acid forms salt in both the cases, whereas fumaric acid forms either salt or co-crystals.

  12. Acidity of Strong Acids in Water and Dimethyl Sulfoxide.

    PubMed

    Trummal, Aleksander; Lipping, Lauri; Kaljurand, Ivari; Koppel, Ilmar A; Leito, Ivo

    2016-05-26

    Careful analysis and comparison of the available acidity data of HCl, HBr, HI, HClO4, and CF3SO3H in water, dimethyl sulfoxide (DMSO), and gas-phase has been carried out. The data include experimental and computational pKa and gas-phase acidity data from the literature, as well as high-level computations using different approaches (including the W1 theory) carried out in this work. As a result of the analysis, for every acid in every medium, a recommended acidity value is presented. In some cases, the currently accepted pKa values were revised by more than 10 orders of magnitude. PMID:27115918

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

    NASA Astrophysics Data System (ADS)

    Gu, Ling

    2014-03-01

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

  14. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Nitric acid. 173.158 Section 173.158... Nitric acid. (a) Nitric acid exceeding 40 percent concentration may not be packaged with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid...

  15. Identification and characterization of five new classes of chlorogenic acids in burdock (Arctium lappa L.) roots by liquid chromatography/tandem mass spectrometry.

    PubMed

    Jaiswal, Rakesh; Kuhnert, Nikolai

    2011-01-01

    Burdock (Arcticum lappa L.) roots are used in folk medicine and also as a vegetable in Asian countries especially Japan, Korea, and Thailand. We have used LC-MS(n) (n = 2-4) to detect and characterize in burdock roots 15 quantitatively minor fumaric, succinic, and malic acid-containing chlorogenic acids, 11 of them not previously reported in nature. These comprise 3-succinoyl-4,5-dicaffeoyl or 1-succinoyl-3,4-dicaffeoylquinic acid, 1,5-dicaffeoyl-3-succinoylquinic acid, 1,5-dicaffeoyl-4-succinoylquinic acid, and 3,4-dicaffeoyl-5-succinoylquinic acid (M(r) 616); 1,3-dicaffeoyl-5-fumaroylquinic acid and 1,5-dicaffeoyl-4-fumaroylquinic acid (M(r) 614); 1,5-dicaffeoyl-3-maloylquinic acid, 1,4-dicaffeoyl-3-maloylquinic acid, and 1,5-dicaffeoyl-4-maloylquinic acid (M(r) 632); 1,3,5-tricaffeoyl-4-succinoylquinic acid (M(r) 778); 1,5-dicaffeoyl-3,4-disuccinoylquinic acid (M(r) 716); 1,5-dicaffeoyl-3-fumaroyl-4-succinoylquinic acid and 1-fumaroyl-3,5-dicaffeoyl-4-succinoylquinic acid (M(r) 714); dicaffeoyl-dimaloylquinic acid (M(r) 748); and 1,5-dicaffeoyl-3-succinoyl-4-dimaloylquinic acid (M(r) 732). All the structures have been assigned on the basis of LC-MS(n) patterns of fragmentation, relative hydrophobicity, and analogy of fragmentation patterns if compared to caffeoylquinic acids.

  16. Acid rain degradation of nylon

    SciTech Connect

    Kyllo, K.E.

    1984-01-01

    Acid rain, precipitation with a pH less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid of pH 2.0, 3.0, and 4.4 were exposed to light in an Atlas Xenon-arc fadeometer at 63/sup 0/C and 65% R.H. for up to 640 AATCC Fading Units. The untreated and acid treated nylon fabrics were also exposed to similar temperature and humidity condition without light. Nylon degradation was determined by changes in breaking strength, elongation, molecular weight, color, amino end group concentration (NH/sub 2/) and /sup 13/C NMR spectra. Physical damage was assessed using SEM.

  17. A Simpler Nucleic Acid

    NASA Technical Reports Server (NTRS)

    Orgel, Leslie

    2000-01-01

    It has been supposed that for a nucleic acid analog to pair with RNA it must, like RNA, have a backbone with at least a sixatom repeat; a shorter backbone presumably would not stretch far enough to bind RNA properly. The Eschenmoser group has shown, however, that this first impression is incorrect.As they report in their new paper, Eschenmoser and co-workers ( I ) have now synthesized a substantial number of these polymers, which are called (L)-a-threofuranosyl oligonucleotides or TNAs. They are composed of bases linked to a threose sugar-phosphate backbone, with phosphodiester bonds connecting the nucleotides. The investigators discovered that pairs of complementary TNAs do indeed form stable Watson-Crick double helices and, perhaps more importantly, that TNAs form stable double helices with complementary RNAs and DNAs.

  18. The regulation of phosphoenolpyruvate carboxykinase and the NADP-linked malic enzyme in Aspergillus nidulans.

    PubMed

    Kelly, J M; Hynes, M J

    1981-04-01

    It has previously been suggested that the synthesis of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) in Aspergillus nidulans is regulated by a repression-derepression mechanism involving a glycolytic intermediate, and not by induction. Results obtained using compounds that enter the tricarboxylic acid cycle via 2-oxoglutarate, and that can supply both a carbon and a nitrogen source for A. nidulans, suggest it is more likely that the synthesis of phosphoenolpyruvate carboxykinase is inducible, and only weakly regulated by carbon catabolite repression. a similar study of the regulation of the NADP-linked malic enzyme (EC 1.1.1.40) indicates that it too may be inducible.

  19. [Hydrofluoric acid poisoning: case report].

    PubMed

    Cortina, Tatiana Judith; Ferrero, Hilario Andrés

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  1. Acidic gas capture by diamines

    SciTech Connect

    Rochelle, Gary; Hilliard, Marcus

    2011-05-10

    Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

  2. Molecular structural studies of lichen substances II: atranorin, gyrophoric acid, fumarprotocetraric acid, rhizocarpic acid, calycin, pulvinic dilactone and usnic acid

    NASA Astrophysics Data System (ADS)

    Edwards, Howell G. M.; Newton, Emma M.; Wynn-Williams, David D.

    2003-06-01

    The FT-Raman and infrared vibrational spectra of some important lichen compounds from two metabolic pathways are characterised. Key biomolecular marker bands have been suggested for the spectroscopic identification of atranorin, gyrophoric acid, fumarprotocetraric acid rhizocarpic acid, calycin, pulvinic dilactone and usnic acid. A spectroscopic protocol has been defined for the detection of these molecules in organisms subjected to environmental stresses such as UV-radiation exposure, desiccation and low temperatures. Use of the protocol will be made for the assessment of survival strategies used by stress-tolerant lichens in Antarctic cold deserts.

  3. Cryoprotection from bacterial teichoic acid

    NASA Astrophysics Data System (ADS)

    Rice, Charles V.; Harrison, William; Kirkpatrick, Karl; Brown, Eric D.

    2009-08-01

    Recent studies from our lab demonstrated that teichoic acid is surrounded by liquid water at -40 °C. The size and shape of the liquid water pockets has been visualized with fluorescence microscopy images of aqueous Rhodamine- B solutions. The long, thin channels surround ice crystals with a size of 5-20 microns. Subsequent studies show that B. subtilis Gram-positive bacteria are sequestered into large pockets without added teichoic acid. Here, the ice crystals are orders of manitude larger. When bacteria are mixed with teichoic acid solutions, the distribution of bacteria changes dramatically. The smaller ice crystals allow the bacteria to align in the thin channels of liquid water seen with teichoic acid only. The role of teichoic acid in the freeze tolerance was examined with live/dead fluorescence assays of bacteria mixed with teichoic acid. These quantitative assays were used to determine if teichoic acid acts in a synergetic fashion to enhance the survivability of E. coli, a gram-negative species which lacks teichoic acid. Additionally, we have obtained B. subtilis mutants lacking wall-associated teichoic acids to evaluate cryoprotection compared to the wild-type strain.

  4. Sulfuric acid as autocatalyst in the formation of sulfuric acid.

    PubMed

    Torrent-Sucarrat, Miquel; Francisco, Joseph S; Anglada, Josep M

    2012-12-26

    Sulfuric acid can act as a catalyst of its own formation. We have carried out a computational investigation on the gas-phase formation of H(2)SO(4) by hydrolysis of SO(3) involving one and two water molecules, and also in the presence of sulfuric acid and its complexes with one and two water molecules. The hydrolysis of SO(3) requires the concurrence of two water molecules, one of them acting as a catalyzer, and our results predict an important catalytic effect, ranging between 3 and 11 kcal·mol(-1) when the catalytic water molecule is substituted by a sulfuric acid molecule or one of its hydrates. In these cases, the reaction products are either bare sulfuric acid dimer or sulfuric acid dimer complexed with a water molecule. There are broad implications from these new findings. The results of the present investigation show that the catalytic effect of sulfuric acid in the SO(3) hydrolysis can be important in the Earth's stratosphere, in the heterogeneous formation of sulfuric acid and in the formation of aerosols, in H(2)SO(4) formation by aircraft engines, and also in understanding the formation of sulfuric acid in the atmosphere of Venus.

  5. Hydrazides of carboxylic acids as inhibitors of steel acidic corrosion

    SciTech Connect

    Aitov, R.G.; Shein, A.B.; Lesnov, A.E.

    1994-09-01

    Hydrazides of carboxylic acids (HCA) inhibit the corrosion of ferrous materials in acids and netral solutions such as stratum and waste waters of oil deposits. In this work, the authors try to explain the above-mentioned difference and to consider HCA as inhibitors of steel hydrogenation.

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

    PubMed Central

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

    2016-01-01

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism. PMID:26742061

  7. A comparison of chromic acid and sulfuric acid anodizing

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1992-01-01

    Because of federal and state mandates restricting the use of hexavalent chromium, it was deemed worthwhile to compare the corrosion protection afforded 2219-T87 aluminum alloy by both Type I chromic acid and Type II sulfuric acid anodizing per MIL-A-8625. Corrosion measurements were made on large, flat 2219-T87 aluminum alloy sheet material with an area of 1 cm(exp 2) exposed to a corrosive medium of 3.5-percent sodium chloride at pH 5.5. Both ac electrochemical impedance spectroscopy and the dc polarization resistance techniques were employed. The results clearly indicate that the corrosion protection obtained by Type II sulfuric acid anodizing is superior, and no problems should result by substituting Type II sulfuric acid anodizing for Type I chromic acid anodizing.

  8. Acid rain on Acid soil: a new perspective.

    PubMed

    Krug, E C; Frink, C R

    1983-08-01

    Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.

  9. Carbonic Acid Retreatment of Biomass

    SciTech Connect

    Baylor university

    2003-06-01

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

  10. Carbonic Acid Pretreatment of Biomass

    SciTech Connect

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

    2003-05-31

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

  11. Anacardic Acid, Salicylic Acid, and Oleic Acid Differentially Alter Cellular Bioenergetic Function in Breast Cancer Cells.

    PubMed

    Radde, Brandie N; Alizadeh-Rad, Negin; Price, Stephanie M; Schultz, David J; Klinge, Carolyn M

    2016-11-01

    Anacardic acid is a dietary and medicinal phytochemical that inhibits breast cancer cell proliferation and uncouples oxidative phosphorylation (OXPHOS) in isolated rat liver mitochondria. Since mitochondrial-targeted anticancer therapy (mitocans) may be useful in breast cancer, we examined the effect of anacardic acid on cellular bioenergetics and OXPHOS pathway proteins in breast cancer cells modeling progression to endocrine-independence: MCF-7 estrogen receptor α (ERα)+ endocrine-sensitive; LCC9 and LY2 ERα+, endocrine-resistant, and MDA-MB-231 triple negative breast cancer (TNBC) cells. At concentrations similar to cell proliferation IC50 s, anacardic acid reduced ATP-linked oxygen consumption rate (OCR), mitochondrial reserve capacity, and coupling efficiency while increasing proton leak, reflecting mitochondrial toxicity which was greater in MCF-7 compared to endocrine-resistant and TNBC cells. These results suggest tolerance in endocrine-resistant and TNBC cells to mitochondrial stress induced by anacardic acid. Since anacardic acid is an alkylated 2-hydroxybenzoic acid, the effects of salicylic acid (SA, 2-hydroxybenzoic acid moiety) and oleic acid (OA, monounsaturated alkyl moiety) were tested. SA inhibited whereas OA stimulated cell viability. In contrast to stimulation of basal OCR by anacardic acid (uncoupling effect), neither SA nor OA altered basal OCR- except OA inhibited basal and ATP-linked OCR, and increased ECAR, in MDA-MB-231 cells. Changes in OXPHOS proteins correlated with changes in OCR. Overall, neither the 2-hydroxybenzoic acid moiety nor the monounsaturated alky moiety of anacardic acid is solely responsible for the observed mitochondria-targeted anticancer activity in breast cancer cells and hence both moieties are required in the same molecule for the observed effects. J. Cell. Biochem. 117: 2521-2532, 2016. © 2016 Wiley Periodicals, Inc. PMID:26990649

  12. Quantification and role of organic acids in cucumber root exudates in Trichoderma harzianum T-E5 colonization.

    PubMed

    Zhang, Fengge; Meng, Xiaohui; Yang, Xingming; Ran, Wei; Shen, Qirong

    2014-10-01

    The ability to colonize on plant roots is recognized as one of the most important characteristics of the beneficial fungi Trichoderma spp. The aim of this study is to prove that the utilization of organic acids is a major trait of Trichoderma harzianum T-E5 for colonization of cucumber roots. A series experiments in split-root hydroponic system and in vitro were designed to demonstrate the association between the utilization of organic acids and T-E5 colonization on cucumber roots. In the split-root hydroponic system, inoculation with T-E5 (T) significantly increased the biomass of cucumber plants compared with CK (non-inoculation with T-E5). The T-E5 hyphae densely covering the cucumber root surface were observed by scanning electron microscopy (SEM). Three organic acids (oxalic acid, malic acid and citric acid) were identified from both the CK and T treatments by HPLC and LC/ESI-MS procedures. The amounts of oxalic acid and malic acid in T were significantly higher than those in CK. All the organic acids exhibited different and significant stimulation effects on the mycelial growth and conidial germination of T-E5 in vitro. An additional hydroponic experiment demonstrated the positive effects of organic acids on the T-E5 colonization of cucumber roots. In conclusion, the present study revealed that certain organic acids could be used as nutritional sources for Trichoderma harzianum T-E5 to reinforce its population on cucumber roots.

  13. Interconnection between tricarboxylic acid cycle and energy generation in microbial fuel cell performed by desulfuromonas acetoxidans IMV B-7384

    NASA Astrophysics Data System (ADS)

    Vasyliv, Oresta M.; Maslovska, Olga D.; Ferensovych, Yaroslav P.; Bilyy, Oleksandr I.; Hnatush, Svitlana O.

    2015-05-01

    Desulfuromonas acetoxidans IMV B-7384 is exoelectrogenic obligate anaerobic sulfur-reducing bacterium. Its one of the first described electrogenic bacterium that performs complete oxidation of an organic substrate with electron transfer directly to the electrode in microbial fuel cell (MFC). This bacterium is very promising for MFC development because of inexpensive cultivation medium, high survival rate and selective resistance to various heavy metal ions. The size of D. acetoxidans IMV B-7384 cells is comparatively small (0.4-0.8×1-2 μm) that is highly beneficial while application of porous anode material because of complete bacterial cover of an electrode area with further significant improvement of the effectiveness of its usage. The interconnection between functioning of reductive stage of tricarboxylic acid (TCA) cycle under anaerobic conditions, and MFC performance was established. Malic, pyruvic, fumaric and succinic acids in concentration 42 mM were separately added into the anode chamber of MFC as the redox agents. Application of malic acid caused the most stabile and the highest power generation in comparison with other investigated organic acids. Its maximum equaled 10.07±0.17mW/m2 on 136 hour of bacterial cultivation. Under addition of pyruvic, succinic and fumaric acids into the anode chamber of MFC the maximal power values equaled 5.80±0.25 mW/m2; 3.2±0.11 mW/m2, and 2.14±0.19 mW/m2 respectively on 40, 56 and 32 hour of bacterial cultivation. Hence the malic acid conversion via reductive stage of TCA cycle is shown to be the most efficient process in terms of electricity generation by D. acetoxidans IMV B-7384 in MFC under anaerobic conditions.

  14. Acid rain: a background report

    SciTech Connect

    Glustrom, L.; Stolzenberg, J.

    1982-07-08

    This Staff Brief was prepared for the Wisconsin Legislative Council's Special Committee on Acid Rain to provide an introduction to the issue of acid rain. It is divided into four parts. Part I provides an overview on the controversies surrounding the measurement, formation and effects of acid rain. As described in Part I, the term acid rain is used to describe the deposition of acidic components through both wet deposition (e.g., rain or snow) and dry deposition (e.g., direct contact between atmospheric constituents and the land, water or vegetation of the earth). Part II presents background information on state agency activities relating to acid rain in Wisconsin, describes what is known about the occurrence of, susceptibility to and effects of acid rain in Wisconsin, and provides information related to man-made sources of sulfur and nitrogen oxides in Wisconsin. Part III describes major policies and regulations relating to acid rain which have been or are being developed jointly by the United States and Canadian governments, by the United States government and by the State of Wisconsin. Part IV briefly discusses possible areas for Committee action.

  15. Acid Rain: An Educational Opportunity?

    ERIC Educational Resources Information Center

    Marion, James I.

    1984-01-01

    Deals with how educators can handle the subject of acid rain; illustrates suggestions with experiences of grade nine students visiting Frost Valley Environmental Education Center (Oliverea, New York) to learn scientific concepts through observation of outdoor phenomena, including a stream; and discusses acid rain, pH levels, and pollution control…

  16. Acid rain & electric utilities II

    SciTech Connect

    1997-12-31

    This document presents reports which were presented at the Acid Rain and Electric Utilities Conference. Topics include environmental issues and electric utilities; acid rain program overview; global climate change and carbon dioxide; emissions data management; compliance; emissions control; allowance and trading; nitrogen oxides; and assessment. Individual reports have been processed separately for the United States Department of Energy databases.

  17. Acid Rain: The Scientific Challenge.

    ERIC Educational Resources Information Center

    Godfrey, Paul J.

    1991-01-01

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

  18. Acid Precipitation: Causes and Consequences.

    ERIC Educational Resources Information Center

    Babich, Harvey; And Others

    1980-01-01

    This article is the first of three articles in a series on the acid rain problem in recent years. Discussed are the causes of acid precipitation and its consequences for the abiotic and biotic components of the terrestrial and aquatic ecosystems, and for man-made materials. (Author/SA)

  19. Acid Rain: What's the Forecast?

    ERIC Educational Resources Information Center

    Bybee, Rodger

    1984-01-01

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

  20. Synthesis of pyromellitic acid esters

    NASA Technical Reports Server (NTRS)

    Fedorova, V. A.; Donchak, V. A.; Martynyuk-Lototskaya, A. N.

    1985-01-01

    The ester acids necessary for studyng the thermochemical properties of pyromellitic acid (PMK)-based peroxides were investigated. Obtaining a tetramethyl ester of a PMK was described. The mechanism of an esterification reaction is discussed, as is the complete esterification of PMK with primary alcohol.

  1. Getting Back to Basics (& Acidics)

    ERIC Educational Resources Information Center

    Rhodes, Sam

    2006-01-01

    This article describes a few novel acid-base experiments intended to introduce students to the basic concepts of acid-base chemistry and provide practical examples that apply directly to the study of biology and the human body. Important concepts such as the reaction between carbon dioxide and water, buffers and protein denaturation, are covered.…

  2. Acid Tests and Basic Fun.

    ERIC Educational Resources Information Center

    McBride, John W.

    1995-01-01

    Explores acids and bases using different indicators, such as turmeric, purple grape juice, and lichens. Because some of these indicators are not as sensitive as cabbage juice or litmus paper, determining to which acids and bases each indicator is sensitive presents an enjoyable, problem-solving challenge for students. Presents directions for…

  3. Acid rain and environmental policy

    SciTech Connect

    Jacobson, J.S.

    1981-10-01

    Various seemingly paradoxical scientific questions are posed which relate to the problem of acid rain and its effect on the environment and environmental policy. The first paradox discussed concerns the supposed increase in fossil fuel usage over the last several decades, with the resultant increases in emissions of pollutants from the combustion of fuels which cause acid rain. Despite these increases, experts do not agree on whether acidity of rain has increased in eastern North America. The second paradox concerns the effect of acid rain on vegetation. If the rain is supposedly harmful, why have some reports shown increases and others, decreases in the growth of crops and trees with the application of simulated acid rain. The third paradox concerns the effect of acid rains on fish life in lakes. If acid rain falls throughout eastern North America, why have some lakes become acid and lost fish populations while others have not. Since unequivocal answers to these scientific questions are not available, a systematic approach is needed for developing policy which can be useful for solving the problem. It appears that traditional cost-benefit analysis can not be the sole basis for decision-making, but that it will be helpful. Research needs must be identified, and the upper and lower limits for alternative strategies must be determined. 14 references, 1 table.

  4. Impacts of acid rain legislation

    SciTech Connect

    Addison, E.L.

    1983-01-01

    The author warns against hasty acid rain legislation that would involve billions of dollars and affect thousands of jobs. He recommends further study into the causes of high acidity in lakes and streams. He states that there are too many uncertainties of whether the problem would be solved by reducing sulfur dioxide emissions from coal-fired power plants. (DMC)

  5. Acid rain: effects on fish and wildlife

    SciTech Connect

    Mayer, K.S.; Multer, E.P.; Schreiber, R.K.

    1984-01-01

    The following questions concerning acid rain are discussed: what is acid rain; what causes acid rain; where do sulfur and nitrogen oxides originate; what areas in the U.S. are susceptible to acid rain; are there early warning signals of acidification to aquatic resources; how does acid rain affect fishery resources; does acid rain affect wildlife; and how can effects of acid rain be reduced.

  6. [Effects of low molecular organic acids on nitrogen accumulation, nodulation, and nitrogen fixation of soybean (Glycine max L.) under phosphorus deficiency stress].

    PubMed

    Wang, Shu-Qi; Han, Xiao-Zeng; Qiao, Yun-Fa; Yan, Jun; Li, Xiao-Hui

    2009-05-01

    A greenhouse sand culture experiment was conducted to study the effects of citric acid, oxalic acid, malic acid, and their mixture on the nitrogen accumulation, nodulation, and nitrogen fixation of soybean. After the application of test low molecular weight organic acids, the nitrogen accumulation in the aboveground part of soybean decreased by 17.6%-44.9% at seedling stage, 29.8%-88.4% at flowering stage, 9.18%-69.6% at podding stage, and 2.21%-41.7% at maturing stage). In the meanwhile, the nodule number, nitrogenase activity, and leghemoglobin content decreased by 11.4%-59.6%, 80.5%-91.7%, and 11.9%-59.9%, respectively, resulting in a significant decrease (9.71%-64.5%) of nitrogen fixation of soybean, compared with the control. The inhibitory effect of test low molecular weight organic acids increased with their increasing concentration. Oxalic acid had a higher inhibitory effect than citric acid and malic acid, and the mixture of the three organic acids had an enhanced inhibitory effect.

  7. Quantitative determination of carboxylic acids, amino acids, carbohydrates, ethanol and hydroxymethylfurfural in honey by (1)H NMR.

    PubMed

    del Campo, Gloria; Zuriarrain, Juan; Zuriarrain, Andoni; Berregi, Iñaki

    2016-04-01

    A method using (1)H NMR spectroscopy has been developed to quantify simultaneously thirteen analytes in honeys without previous separation or pre-concentration steps. The method has been successfully applied to determine carboxylic acids (acetic, formic, lactic, malic and succinic acids), amino acids (alanine, phenylalanine, proline and tyrosine), carbohydrates (α- and β-glucose and fructose), ethanol and hydroxymethylfurfural in eucalyptus, heather, lavender, orange blossom, thyme and rosemary honeys. Quantification was performed by using the area of the signal of each analyte in the honey spectra, together with external standards. The regression analysis of the signal area against concentration plots, used for the calibration of each analyte, indicates a good linearity over the concentration ranges found in honeys, with correlation coefficients higher than 0.985 for the thirteen quantified analytes. The recovery studies give values over the 93.7-105.4% range with relative standard deviations lower than 7.4%. Good precision, with relative standard deviations over the range of 0.78-5.21% is obtained. PMID:26593586

  8. Quantitative determination of carboxylic acids, amino acids, carbohydrates, ethanol and hydroxymethylfurfural in honey by (1)H NMR.

    PubMed

    del Campo, Gloria; Zuriarrain, Juan; Zuriarrain, Andoni; Berregi, Iñaki

    2016-04-01

    A method using (1)H NMR spectroscopy has been developed to quantify simultaneously thirteen analytes in honeys without previous separation or pre-concentration steps. The method has been successfully applied to determine carboxylic acids (acetic, formic, lactic, malic and succinic acids), amino acids (alanine, phenylalanine, proline and tyrosine), carbohydrates (α- and β-glucose and fructose), ethanol and hydroxymethylfurfural in eucalyptus, heather, lavender, orange blossom, thyme and rosemary honeys. Quantification was performed by using the area of the signal of each analyte in the honey spectra, together with external standards. The regression analysis of the signal area against concentration plots, used for the calibration of each analyte, indicates a good linearity over the concentration ranges found in honeys, with correlation coefficients higher than 0.985 for the thirteen quantified analytes. The recovery studies give values over the 93.7-105.4% range with relative standard deviations lower than 7.4%. Good precision, with relative standard deviations over the range of 0.78-5.21% is obtained.

  9. Lead-acid battery

    SciTech Connect

    Rowlette, J.J.

    1983-09-20

    A light weight lead-acid battery is disclosed having a positive terminal and a negative terminal and including one or more cells or grid stacks having a plurality of vertically stacked conductive monoplates with positive active material and negative active material deposited on alternating plates in the cell or grid stack. Electrolyte layers positioned between each monoplate are included to provide a battery cell having four sides which is capable of being electrically charged and discharged. Two vertical positive bus bars are provided on opposite sides of the battery cell for connecting the monoplates with positive active material together in parallel current conducting relation. In addition, two negative bus bars on opposite sides of the battery cell each being adjacent the positive bus bars are provided for connecting the monoplates with negative active material together in parallel current conducting relation. The positive and negative bus bars not only provide a low resistance method for connecting the plurality of conductive monoplates of their respective battery terminals but also provides support and structural strength to the battery cell structure. In addition, horizontal orientation of monoplates is provided in a vertical stacking arrangement to reduce electrolyte stratification and short circuiting due to flaking of positive and negative active materials from the monoplates.

  10. Lead-acid battery

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1983-01-01

    A light weight lead-acid battery (30) having a positive terminal (36) and a negative terminal (34) and including one or more cells or grid stacks having a plurality of vertically stacked conductive monoplates (10, 20) with positive active material and negative active material deposited on alternating plates in the cell or grid stack. Electrolyte layers (26, 28) positioned between each monoplate are included to provide a battery cell having four sides which is capable of being electrically charged and discharged. Two vertical positive bus bars (42, 43) are provided on opposite sides of the battery cell for connecting the monoplates (10) with positive active material together in parallel current conducting relation. In addition, two negative bus bars (38, 39) on opposite sides of the battery cell each being adjacent the positive bus bars are provided for connecting the monoplates (20) with negative active material together in parallel current conducting relation. The positive (42, 43) and negative (38, 39) bus bars not only provide a low resistance method for connecting the plurality of conductive monoplates of their respective battery terminals (36, 34) but also provides support and structural strength to the battery cell structure. In addition, horizontal orientation of monoplates (10, 20) is provided in a vertical stacking arrangement to reduce electrolyte stratification and short circuiting due to flaking of positive and negative active materials from the monoplates.

  11. Metabolic pathways regulated by γ-aminobutyric acid (GABA) contributing to heat tolerance in creeping bentgrass (Agrostis stolonifera)

    PubMed Central

    Li, Zhou; Yu, Jingjin; Peng, Yan; Huang, Bingru

    2016-01-01

    γ-Aminobutyric acid is a non-protein amino acid involved in various metabolic processes. The objectives of this study were to examine whether increased GABA could improve heat tolerance in cool-season creeping bentgrass through physiological analysis, and to determine major metabolic pathways regulated by GABA through metabolic profiling. Plants were pretreated with 0.5 mM GABA or water before exposed to non-stressed condition (21/19 °C) or heat stress (35/30 °C) in controlled growth chambers for 35 d. The growth and physiological analysis demonstrated that exogenous GABA application significantly improved heat tolerance of creeping bentgrass. Metabolic profiling found that exogenous application of GABA led to increases in accumulations of amino acids (glutamic acid, aspartic acid, alanine, threonine, serine, and valine), organic acids (aconitic acid, malic acid, succinic acid, oxalic acid, and threonic acid), sugars (sucrose, fructose, glucose, galactose, and maltose), and sugar alcohols (mannitol and myo-inositol). These findings suggest that GABA-induced heat tolerance in creeping bentgrass could involve the enhancement of photosynthesis and ascorbate-glutathione cycle, the maintenance of osmotic adjustment, and the increase in GABA shunt. The increased GABA shunt could be the supply of intermediates to feed the tricarboxylic acid cycle of respiration metabolism during a long-term heat stress, thereby maintaining metabolic homeostasis. PMID:27455877

  12. Metabolic pathways regulated by γ-aminobutyric acid (GABA) contributing to heat tolerance in creeping bentgrass (Agrostis stolonifera).

    PubMed

    Li, Zhou; Yu, Jingjin; Peng, Yan; Huang, Bingru

    2016-07-26

    γ-Aminobutyric acid is a non-protein amino acid involved in various metabolic processes. The objectives of this study were to examine whether increased GABA could improve heat tolerance in cool-season creeping bentgrass through physiological analysis, and to determine major metabolic pathways regulated by GABA through metabolic profiling. Plants were pretreated with 0.5 mM GABA or water before exposed to non-stressed condition (21/19 °C) or heat stress (35/30 °C) in controlled growth chambers for 35 d. The growth and physiological analysis demonstrated that exogenous GABA application significantly improved heat tolerance of creeping bentgrass. Metabolic profiling found that exogenous application of GABA led to increases in accumulations of amino acids (glutamic acid, aspartic acid, alanine, threonine, serine, and valine), organic acids (aconitic acid, malic acid, succinic acid, oxalic acid, and threonic acid), sugars (sucrose, fructose, glucose, galactose, and maltose), and sugar alcohols (mannitol and myo-inositol). These findings suggest that GABA-induced heat tolerance in creeping bentgrass could involve the enhancement of photosynthesis and ascorbate-glutathione cycle, the maintenance of osmotic adjustment, and the increase in GABA shunt. The increased GABA shunt could be the supply of intermediates to feed the tricarboxylic acid cycle of respiration metabolism during a long-term heat stress, thereby maintaining metabolic homeostasis.

  13. Metabolic pathways regulated by γ-aminobutyric acid (GABA) contributing to heat tolerance in creeping bentgrass (Agrostis stolonifera).

    PubMed

    Li, Zhou; Yu, Jingjin; Peng, Yan; Huang, Bingru

    2016-01-01

    γ-Aminobutyric acid is a non-protein amino acid involved in various metabolic processes. The objectives of this study were to examine whether increased GABA could improve heat tolerance in cool-season creeping bentgrass through physiological analysis, and to determine major metabolic pathways regulated by GABA through metabolic profiling. Plants were pretreated with 0.5 mM GABA or water before exposed to non-stressed condition (21/19 °C) or heat stress (35/30 °C) in controlled growth chambers for 35 d. The growth and physiological analysis demonstrated that exogenous GABA application significantly improved heat tolerance of creeping bentgrass. Metabolic profiling found that exogenous application of GABA led to increases in accumulations of amino acids (glutamic acid, aspartic acid, alanine, threonine, serine, and valine), organic acids (aconitic acid, malic acid, succinic acid, oxalic acid, and threonic acid), sugars (sucrose, fructose, glucose, galactose, and maltose), and sugar alcohols (mannitol and myo-inositol). These findings suggest that GABA-induced heat tolerance in creeping bentgrass could involve the enhancement of photosynthesis and ascorbate-glutathione cycle, the maintenance of osmotic adjustment, and the increase in GABA shunt. The increased GABA shunt could be the supply of intermediates to feed the tricarboxylic acid cycle of respiration metabolism during a long-term heat stress, thereby maintaining metabolic homeostasis. PMID:27455877

  14. Synthesis of higher monocarboxylic acids

    SciTech Connect

    Taikov, B.F.; Novakovskii, E.M.; Zhelkovskaya, V.P.; Shadrova, V.N.; Shcherbik, P.K.

    1981-01-01

    Brown-coal and peat waxes contain higher monocarboxylic acids, alcohols and esters of them as their main components. In view of this, considerable interest is presented by the preparation of individual compounds among those mentioned above, which is particularly important in the study of the composition and development of the optimum variants of the chemical processing of the waxes. In laboratory practice, to obtain higher monocarboxylic acids use is generally made of electrosynthesis according to Kolbe which permits unbranched higher aliphatic acids with given lengths of the hydrocarbon chain to be obtained. The aim of the present work was to synthesize higher monocarboxylic acids: arachidic, behenic, lignoceric, pentacosanoic, erotic, heptacosanoic, montanic, nonacosanoic, melissic, dotriacontanoic and tetratriacontanoic, which are present in waxes. Characteristics of synthesized acids are tabulated. 20 refs.

  15. Atmospheric dust and acid rain

    SciTech Connect

    Hedin, L.O.; Likens, G.E.

    1996-12-01

    Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid rain and atmospheric dust? Suggestions range from the improbable to the feasible. One reasonable suggestion is to reduce emissions of acidic pollutants to levels that can be buffered by natural quantities of basic compounds in the atmosphere; such a goal would mean continued reductions in sulfur dioxide and nitrogen oxides, perhaps even greater than those prescribed in the 1990 Amendments to the Clean Air Act in the U.S. 5 figs.

  16. Amino acid management in cancer

    PubMed Central

    Tsun, Zhi-Yang; Possemato, Richard

    2016-01-01

    Amino acids have a dual role in cellular metabolism, as they are both the building blocks for protein synthesis and intermediate metabolites which fuel other biosynthetic reactions. Recent work has demonstrated that deregulation of both arms of amino acid management are common alterations seen in cancer. Among the most highly consumed nutrients by cancer cells are the amino acids glutamine and serine, and the biosynthetic pathways that metabolize them are required in various cancer subtypes and the object of current efforts to target cancer metabolism. Also altered in cancer are components of the machinery which sense amino acid sufficiency, nucleated by the mechanistic target of rapamycin (mTOR), a key regulator of cell growth via modulation of key processes including protein synthesis and autophagy. The precise ways in which altered amino acid management supports cellular transformation remain mostly elusive, and a fuller mechanistic understanding of these processes will be important for efforts to exploit such alterations for cancer therapy. PMID:26277542

  17. Fumaric acid production by fermentation

    PubMed Central

    Roa Engel, Carol A.; Zijlmans, Tiemen W.; van Gulik, Walter M.; van der Wielen, Luuk A. M.

    2008-01-01

    The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations. PMID:18214471

  18. Effect of gallic acid and catechin on Lactobacillus hilgardii 5w growth and metabolism of organic compounds.

    PubMed

    Alberto, M R; Farías, M E; Manca De Nadra, M C

    2001-09-01

    The effects of different concentrations of (+)-catechin and gallic acid on the growth and metabolism of Lactobacillus hilgardii in different media were evaluated. These phenolic compounds at concentrations normally present in wine not only stimulated the growth rate but also resulted in greater cell densities during the stationary phase of growth in both media. During the first hours of growth both phenolic compounds activated the rate of glucose and fructose utilization and only catechin increased the malic acid consumption rate. Gallic acid and catechin were consumed from the beginning of L. hilgardii growth. All cited effects were increased when the cells were precultivated in the presence of phenolic compounds, especially in the FT80 medium. As stimulating agents of L. hilgardii 5w growth, gallic acid and catechin could increase the risk of spoilage lactic acid bacteria in wine.

  19. Formation of acrylic acid from lactic acid in supercritical water

    SciTech Connect

    Mok, W.S.L.; Antal, M.J. Jr. ); Jones, M. Jr. )

    1989-09-15

    Supercritical (SC) water is an unusual medium in which fast and specific heterolytic reactions can be conducted at temperatures as high as 400{degree}C. In supercritical water, lactic acid decomposes into gaseous and liquid products via three primary reaction pathways. Products of the acid-catalyzed heterolytic decarbonylation pathway are carbon monoxide, water, and acetaldehyde. Products of the homolytic, decarboxylation pathway are carbon dioxide, hydrogen, and acetaldehyde. Products of the heterolytic, dehydration pathway are acrylic acid and water. The intramolecular nucleophilic displacement of the {alpha}-hydroxyl by the carbonyl group of lactic acid, producing {alpha}-propiolactone as an unstable intermediate which subsequently rearranges to become the unsaturated acid, is a likely mechanism for acrylic acid formation, although an intramolecular E2 elimination initiated by attack of the carbonyl oxygen on a methyl hydrogen cannot be ruled out. Support for the former mechanism comes in part from the observed 100% relative yield of acrylic acid from {beta}-propiolactone in SC water.

  20. Synthesis of l-(+)-Tartaric Acid from l-Ascorbic Acid via 5-Keto-d-Gluconic Acid in Grapes

    PubMed Central

    Saito, Kazumi; Kasai, Zenzaburo

    1984-01-01

    5-Keto-l-idionic acid (≡5-keto-d-gluconic acid, d-xylo-5-hexulosonic acid) was found as a metabolic product of l-ascorbic acid in slices of immature grapes, Vitis labrusca L. cv `Delaware'. Specifically labeled compounds, recognized as metabolic products of l-ascorbic acid in grapes, were fed to young grape tissues to investigate the metabolic pathway from l-ascorbic acid to l-(+)-tartaric acid. Label from dehydro-l-[1-14C]ascorbic acid, 2-keto-l-[1-14C]idonic acid (l-xylo-2-hexulosonic acid), l-[1-14C]idonic acid, or 5-keto-l-[1-14C] idonic acid was incorporated into l-(+)-tartaric acid in high yields as it was in the l-[1-14C]ascorbic acid experiment. In a double label experiment involving a mixture of l-[1-14C]idonic acid and l-[2-3H]idonic acid, the 3H/14C ratios of 5-keto-l-idonic acid and l-(+)-tartaric acid synthesized in young grape leaves were almost the same as the value of the l-idonic acid fed. Label from 5-keto-l-[6-14C]idonic acid was incorporated into sugars and insoluble residue in the same way as l-[6-14C]ascorbic acid was metabolized in grapes. These results provide strong evidence that in grapes l-(+)-tartaric acid is synthesized from the C4 fragment that corresponds to the C1 to C4 group of the 5-keto-l-idonic acid derived from l-ascorbic acid via 2-keto-l-idonic acid and l-idonic acid. PMID:16663792

  1. Molten fatty acid based microemulsions.

    PubMed

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

    2016-06-21

    We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound. PMID:27241163

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

    PubMed

    Pfeuffer, Maria; Jaudszus, Anke

    2016-07-01

    The odd-chain fatty acids (OCFAs) pentadecanoic acid (15:0) and heptadecanoic acid (17:0), which account for only a small proportion of total saturated fatty acids in milk fat and ruminant meat, are accepted biomarkers of dairy fat intake. However, they can also be synthesized endogenously, for example, from gut-derived propionic acid (3:0). A number of studies have shown an inverse association between OCFA concentrations in human plasma phospholipids or RBCs and risk of type 2 diabetes and cardiovascular disease. We propose a possible involvement in metabolic regulation from the assumption that there is a link between 15:0 and 17:0 and the metabolism of other short-chain, medium-chain, and longer-chain OCFAs. The OCFAs 15:0 and 17:0 can be elongated to very-long-chain FAs (VLCFAs) such as tricosanoic acid (23:0) and pentacosanoic acid (25:0) in glycosphingolipids, particularly found in brain tissue, or can be derived from these VLCFAs. Their chains can be shortened, yielding propionyl-coenzyme A (CoA). Propionyl-CoA, by succinyl-CoA, can replenish the citric acid cycle (CAC) with anaplerotic intermediates and, thus, improve mitochondrial energy metabolism. Mitochondrial function is compromised in a number of disorders and may be impaired with increasing age. Optimizing anaplerotic intermediate availability for the CAC may help to cope with demands in times of increased metabolic stress and with aging. OCFAs may serve as substrates for synthesis of both odd-numbered VLCFAs and propionyl-CoA or store away excess propionic acid. PMID:27422507

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

    PubMed

    Pfeuffer, Maria; Jaudszus, Anke

    2016-07-01

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

  4. Physiological and Metabolic Effects of 5-Aminolevulinic Acid for Mitigating Salinity Stress in Creeping Bentgrass

    PubMed Central

    Yang, Zhimin; Chang, Zuoliang; Sun, Lihong; Yu, Jingjin; Huang, Bingru

    2014-01-01

    The objectives of this study were to determine whether foliar application of a chlorophyll precursor, 5-aminolevulinic acid (ALA), could mitigate salinity stress damages in perennial grass species by regulating photosynthetic activities, ion content, antioxidant metabolism, or metabolite accumulation. A salinity-sensitive perennial grass species, creeping bentgrass (Agrostis stolonifera), was irrigated daily with 200 mM NaCl for 28 d, which were foliar sprayed with water or ALA (0.5 mg L−1) weekly during the experiment in growth chamber. Foliar application of ALA was effective in mitigating physiological damage resulting from salinity stress, as manifested by increased turf quality, shoot growth rate, leaf relative water content, chlorophyll content, net photosynthetic rate, stomatal conductance and transpiration rate. Foliar application of ALA also alleviated membrane damages, as shown by lower membrane electrolyte leakage and lipid peroxidation, which was associated with increases in the activities of antioxidant enzymes. Leaf content of Na+ was reduced and the ratio of K+/Na+ was increased with ALA application under salinity stress. The positive effects of ALA for salinity tolerance were also associated with the accumulation of organic acids (α-ketoglutaric acid, succinic acid, and malic acid), amino acids (alanine, 5-oxoproline, aspartic acid, and γ -aminobutyric acid), and sugars (glucose, fructose, galactose, lyxose, allose, xylose, sucrose, and maltose). ALA-mitigation of physiological damages by salinity could be due to suppression of Na+ accumulation and enhanced physiological and metabolic activities related to photosynthesis, respiration, osmotic regulation, and antioxidant defense. PMID:25551443

  5. Physiological and metabolic effects of 5-aminolevulinic acid for mitigating salinity stress in creeping bentgrass.

    PubMed

    Yang, Zhimin; Chang, Zuoliang; Sun, Lihong; Yu, Jingjin; Huang, Bingru

    2014-01-01

    The objectives of this study were to determine whether foliar application of a chlorophyll precursor, 5-aminolevulinic acid (ALA), could mitigate salinity stress damages in perennial grass species by regulating photosynthetic activities, ion content, antioxidant metabolism, or metabolite accumulation. A salinity-sensitive perennial grass species, creeping bentgrass (Agrostis stolonifera), was irrigated daily with 200 mM NaCl for 28 d, which were foliar sprayed with water or ALA (0.5 mg L-1) weekly during the experiment in growth chamber. Foliar application of ALA was effective in mitigating physiological damage resulting from salinity stress, as manifested by increased turf quality, shoot growth rate, leaf relative water content, chlorophyll content, net photosynthetic rate, stomatal conductance and transpiration rate. Foliar application of ALA also alleviated membrane damages, as shown by lower membrane electrolyte leakage and lipid peroxidation, which was associated with increases in the activities of antioxidant enzymes. Leaf content of Na+ was reduced and the ratio of K+/Na+ was increased with ALA application under salinity stress. The positive effects of ALA for salinity tolerance were also associated with the accumulation of organic acids (α-ketoglutaric acid, succinic acid, and malic acid), amino acids (alanine, 5-oxoproline, aspartic acid, and γ -aminobutyric acid), and sugars (glucose, fructose, galactose, lyxose, allose, xylose, sucrose, and maltose). ALA-mitigation of physiological damages by salinity could be due to suppression of Na+ accumulation and enhanced physiological and metabolic activities related to photosynthesis, respiration, osmotic regulation, and antioxidant defense.

  6. Effects of organic acids on cadmium and copper sorption and desorption by two calcareous soils.

    PubMed

    Najafi, Sarvenaz; Jalali, Mohsen

    2015-09-01

    Low molecular weight organic acids (LMWOAs) present in soil alter equilibrium pH of soil, and consequently, affect heavy metal sorption and desorption on soil constitutes. This study was conducted to investigate the effects of different concentrations (0.1, 1, 2.5, 5, 10, 30, 40, 50, 70, and 100 mM) of citric, malic, and oxalic acids on sorption and desorption of cadmium (Cd) and copper (Cu) in two calcareous soils. Increasing the concentrations of three LMWOAs decreased the equilibrium pH of soil solutions. The results indicated that increase in organic acids concentrations generally reduced Cd and Cu sorption in soils. Increase concentrations of LMWOAs generally promoted Cd and Cu desorption from soils. A valley-like curve was observed for desorption of Cu after the citric acid concentration increment in soil 2. Increasing the concentrations of three LMWOAs caused a marked decrease in Kd(sorp) values of Cd and Cu in soils. In general, citric acid was the most effective organic acid in reducing sorption and increasing desorption of both metals, and oxalic acid had the minimal impact. The results indicated that LMWOAs had a greater impact on Cu sorption and desorption than Cd, which can be attributed to higher stability constants of organic acids complexes with Cu compared to Cd. It can be concluded that by selecting suitable type and concentration of LMWOAs, mobility, and hence, bioavailability of heavy metals can be changed. So, environmental implications concerning heavy metals mobility might be derived from these findings.

  7. Suppression of sourness: a comparative study involving mixtures of organic acids and sugars.

    PubMed

    Savant, Lotika; McDaniel, Mina R

    2004-05-01

    The degree of sourness suppression of perceptually equisour levels of citric, lactic, and malic acids by equal molar and weight amounts of sucrose, fructose, and glucose was determined in binary mixtures. Equisour acid levels were obtained by magnitude estimation. Mixture intensity ratings were collected on a categorical scale, using trained panelists. In general, equal sugar molarities and weights did not effect equivalent suppression. Instead, the perceived intensity of the sugars appeared to suppress sourness more systematically, implying that dominantly central neural mechanisms underlie suppression. This was confirmed when no significant differences were found between the suppressive abilities of sweetness-matched levels of sucrose, fructose, and an equiratio mixture of the two on citric acid sourness. The possibility of a separate receptor site/mechanism for glucose and a small peripheral component to suppression is also suggested.

  8. Acid soil and acid rain, 2nd edition

    SciTech Connect

    Kennedy, I.R.

    1992-01-01

    This book examines the basic chemical processes involved in acidification in order to better assess their long-term effects on the status of soils, the health of plants and other living species that depend on them. It also discusses acidity, pH and protons their significance in bioenergetics and the consequent role of autotrophic organisms in acidifying ecosystems. This edition incorporates and integrates recent findings that render more explanations of the causes of the environmental impacts of acidity, especially in forests and lakes. Also explores current research into acid rain and soil in order to devise appropriate measures for their amelioration.

  9. Influence of wine-like conditions on arginine utilization by lactic acid bacteria.

    PubMed

    Araque, Isabel; Reguant, Cristina; Rozès, Nicolas; Bordons, Albert

    2011-12-01

    Wine can contain trace amounts of ethyl carbamate (EC), a carcinogen formed when ethanol reacts with carbamyl compounds such as citrulline. EC is produced from arginine by lactic acid bacteria (LAB), e.g., Lactobacillus and Pediococcus. Although the amounts of EC in wine are usually negligible, over the last few years there has been a slight but steady increase, as climate change has increased temperatures and alcohol levels have become proportionately higher, both of which favor EC formation. In this study, resting cells of LAB were used to evaluate the effects of ethanol, glucose, malic acid, and low pH on the ability of non-oenococcal strains of these bacteria to degrade arginine and excrete citrulline. Malic acid was found to clearly inhibit arginine consumption in all strains. The relation between citrulline produced and arginine consumed was clearly higher in the presence of ethanol (10-12%) and at low pH (3.0), which is consistent with both the decreased amount of ornithine produced from arginine and the reduction in arginine degradation. In L. brevis and L. buchneri strains isolated from wine and beer, respectively, the synthesis of citrulline from arginine was highest. PMID:22569760

  10. [Changes in cat behavior as affected by intracerebral microinjections of kynurenine and quinolinic acid].

    PubMed

    Dutov, A A; Tolpyshev, B A

    1986-10-01

    Behavioural changes induced by microinjections of neuroactive tryptophan metabolites: L-kynurenine sulfate (KYN, 50-1,000 micrograms) and quinolinic acid (QA, 20-1,000 micrograms) were studied in chronic experiments on cats with cannulas implanted into nuclei caudati. Unlike KYN, whose effects were scarce and nonspecific, QA (500 and 1,000 micrograms) produced marked motor and emotional shifts. The effects were manifested in contralateral rotatory movements, limb hyperkinesis, emotional strain, malice, fear, aggression with snarling and hissing, attack on provocation. It is suggested that kynurenines and QA can participate in the generation of emotional disorders peculiar for epilepsy. PMID:3768511

  11. Functional nucleic acid probes and uses thereof

    DOEpatents

    Nilsen-Hamilton, Marit

    2006-10-03

    The present invention provides functional nucleic acid probes, and methods of using functional nucleic acid probes, for binding a target to carry out a desired function. The probes have at least one functional nucleic acid, at least one regulating nucleic acid, and at least one attenuator. The functional nucleic acid is maintained in an inactive state by the attenuator and activated by the regulating nucleic acid only in the presence of a regulating nucleic acid target. In its activated state the functional nucleic acid can bind to its target to carry out a desired function, such as generating a signal, cleaving a nucleic acid, or catalyzing a reaction.

  12. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and... Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid...

  13. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and... Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid...

  14. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and... Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid...

  15. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and....1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid occurs naturally are...

  16. 21 CFR 189.155 - Monochloroacetic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Monochloroacetic acid. 189.155 Section 189.155... Human Food § 189.155 Monochloroacetic acid. (a) Monochloroacetic acid is the chemical chloroacetic acid... in alcoholic and nonalcoholic beverages. Monochloroacetic acid is permitted in food package...

  17. Diabetes and Alpha Lipoic Acid

    PubMed Central

    Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E, and glutathione. It also boosts antioxidant defense system through Nrf-2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy. PMID:22125537

  18. Cycloadditions for Studying Nucleic Acids.

    PubMed

    Kath-Schorr, Stephanie

    2016-02-01

    Cycloaddition reactions for site-specific or global modification of nucleic acids have enabled the preparation of a plethora of previously inaccessible DNA and RNA constructs for structural and functional studies on naturally occurring nucleic acids, the assembly of nucleic acid nanostructures, therapeutic applications, and recently, the development of novel aptamers. In this chapter, recent progress in nucleic acid functionalization via a range of different cycloaddition (click) chemistries is presented. At first, cycloaddition/click chemistries already used for modifying nucleic acids are summarized, ranging from the well-established copper(I)-catalyzed alkyne-azide cycloaddition reaction to copper free methods, such as the strain-promoted azide-alkyne cycloaddition, tetrazole-based photoclick chemistry and the inverse electron demand Diels-Alder cycloaddition reaction between strained alkenes and tetrazine derivatives. The subsequent sections contain selected applications of nucleic acid functionalization via click chemistry; in particular, site-specific enzymatic labeling in vitro, either via DNA and RNA recognizing enzymes or by introducing unnatural base pairs modified for click reactions. Further sections report recent progress in metabolic labeling and fluorescent detection of DNA and RNA synthesis in vivo, click nucleic acid ligation, click chemistry in nanostructure assembly and click-SELEX as a novel method for the selection of aptamers. PMID:27572987

  19. Phytic acid in green leaves.

    PubMed

    Hadi Alkarawi, H; Zotz, G

    2014-07-01

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

  20. Cycloadditions for Studying Nucleic Acids.

    PubMed

    Kath-Schorr, Stephanie

    2016-02-01

    Cycloaddition reactions for site-specific or global modification of nucleic acids have enabled the preparation of a plethora of previously inaccessible DNA and RNA constructs for structural and functional studies on naturally occurring nucleic acids, the assembly of nucleic acid nanostructures, therapeutic applications, and recently, the development of novel aptamers. In this chapter, recent progress in nucleic acid functionalization via a range of different cycloaddition (click) chemistries is presented. At first, cycloaddition/click chemistries already used for modifying nucleic acids are summarized, ranging from the well-established copper(I)-catalyzed alkyne-azide cycloaddition reaction to copper free methods, such as the strain-promoted azide-alkyne cycloaddition, tetrazole-based photoclick chemistry and the inverse electron demand Diels-Alder cycloaddition reaction between strained alkenes and tetrazine derivatives. The subsequent sections contain selected applications of nucleic acid functionalization via click chemistry; in particular, site-specific enzymatic labeling in vitro, either via DNA and RNA recognizing enzymes or by introducing unnatural base pairs modified for click reactions. Further sections report recent progress in metabolic labeling and fluorescent detection of DNA and RNA synthesis in vivo, click nucleic acid ligation, click chemistry in nanostructure assembly and click-SELEX as a novel method for the selection of aptamers.