Science.gov

Sample records for acid sulfites

  1. Monosaccharide production in an acid sulfite process: kinetic modeling.

    PubMed

    Rueda, C; Fernández-Rodríguez, J; Ruiz, G; Llano, T; Coz, A

    2015-02-13

    Spent sulfite liquor is a lignocellulosic waste obtained after the sulfite pulping process. It is mainly formed by sugars and lignosulfonates which are isolated from the pulp during the cooking process. The current work investigates the kinetic modeling of the sulfite process from a biorefinery point of view since monosaccharides present in the spent liquor can be used as a raw material in further biorefinery processes to produce other value-added products. Kinetic parameters of carbohydrate degradation have been determined following sugar and inhibitors from wood to spent liquor, using laboratory scale reactors and different temperatures, 130, 140 and 150 °C. Three types of reaction schemes were developed. Kinetic parameters were obtained for each one using first and n order reactions, using Aspen Custom Modeler. Results show that the best temperature to be used in the process is 130 °C, giving the maximum sugar conversion, 33.91 mol% and obtaining 13.81 mol% of decomposition products.

  2. Effect of pH on sulfite oxidation by Thiobacillus thiooxidans cells with sulfurous acid or sulfur dioxide as a possible substrate.

    PubMed

    Takeuchi, T L; Suzuki, I

    1994-02-01

    The oxidation of sulfite by Thiobacillus thiooxidans was studied at various pH values with changing concentrations of potassium sulfite. The optimal pH for sulfite oxidation by cells was a function of sulfite concentrations, rising with increasing substrate concentrations, while that by the cell extracts was unaffected. The sulfite oxidation by cells was inhibited at high sulfite concentrations, particularly at low pH values. The results from kinetic studies show that the fully protonated form of sulfite, sulfurous acid or sulfur dioxide, is the form which penetrates the cells for the oxidation.

  3. Corrosion of some chromium-nickel steels and alloys in sulfuric acid solutions of sodium sulfite

    SciTech Connect

    Kopeliovich, D.K.; Glagolenko, Yu.V.; Ermolinskii, S.P.

    1988-05-01

    Steels 12Kh18N1OT and 10Kh17N13M3T and alloys 06KhN28MDT and 46KhNM were studied in sulfuric acid solutions containing sodium sulfite and sulfur dioxide to determine the effects of different concentrations of the corrosive constituents on the anodic and cathodic active and passive corrosion behavior of the metals. Polarization curves were obtained with a P-5827 M potentiostat. Addition of sulfite facilitated both electrode processes and the region of the reactive state was broadened due to the shift of passivation potentials to more positive values. The activating effect of sulfite reduction products were confirmed by tests of alloys in spent solutions. This increased likelihood of activation and the decrease of the solutions's own corrosion potential were both attributed to retardation of the cathodic process by lower valence sulfur compounds.

  4. Oxidative degradation of organic acids conjugated with sulfite oxidation in flue gas desulfurization

    SciTech Connect

    Lee, Y.I.

    1986-01-01

    Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (EGD) conditions. The oxidative degradation constant, k/sub 12/, is defined as the ratio of organic acid degradation rate and sulfite oxidation rate after being normalized by the concentrations of organic acid and dissolved S(IV). K/sub 12/, not significantly affected by pH or dissolved oxygen, is around 10/sup -3/ in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Co, Ni, and Fe and is decreased by Mn and halides. Lower dissolved S(IV) magnified these effects. No k/sub 12/ greater than 4 x 10/sup -3/ or smaller than 0.1 x 10/sup -3/ has been observed. A free radical mechanism was proposed to describe the kinetics: (1) sulfate free radical is the major radical responsible to the degradation of organic acid; (2) ferrous generates sulfate radical by reacting with monoxypersulfate to enhance k/sub 12/; (3) manganous consumes sulfate radical to decrease k/sub 12/; (4) dissolved S(IV) competes with ferrous for monoxypersulfate and with manganous for sulfate radical to demonstrate the effects of dissolved S(IV) on k/sub 12/. Hydroxy and sulfonated carboxylic acids degrade approximately three times slower than saturated dicarboxylic acids; while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude faster. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product, glutaric semialdehyde - the major retained product with low manganese, glutaric acid and valeric acids - the major retained product with high manganese, lower molecular weight mono- and dicarboxylic acids, other carbonyl compounds, and hydrocarbons.

  5. Reductive defluorination of perfluorooctanoic acid by hydrated electrons in a sulfite-mediated UV photochemical system.

    PubMed

    Song, Zhou; Tang, Heqing; Wang, Nan; Zhu, Lihua

    2013-11-15

    A method for reductive degradation of perfluorooctanoic acid (PFOA) was established by using a sulfite/UV process. This process led to a PFOA removal of 100% at about 1h and a defluorination ratio of 88.5% at reaction time of 24h under N2 atmosphere, whereas the use of either UV irradiation or SO3(2-) alone induced little defluorination of PFOA under the same conditions. It was confirmed that the reductive defluorination of PFOA was achieved by hydrated electrons being generated from the photo-conversion of SO3(2-) as a mediator. Theoretical reaction kinetic analysis demonstrated that the generation of hydrated electrons was promoted by increasing either SO3(2-) concentration or solution pH, leading to the acceleration of the PFOA defluorination. Accompanying the reduction of PFOA, a small amount of short-chain perfluorocarboxylic acids, less fluorinated carboxylic acids and perfluorinated alkyl sulfonates were generated, all of which were able to be further degraded with further releasing of fluoride ions. Based on the generation, accumulation and distribution of intermediates, hydrated electrons induced defluorination pathway of PFOA was proposed in a sulfite-mediated UV photochemical system.

  6. Effects of sulfhydryl compounds, carbohydrates, organic acids, and sodium sulfite on the formation of lysinoalanine in preserved egg.

    PubMed

    Luo, Xu-Ying; Tu, Yong-Gang; Zhao, Yan; Li, Jian-Ke; Wang, Jun-Jie

    2014-08-01

    To identify inhibitors for lysinoalanine formation in preserved egg, sulfhydryl compounds (glutathione, L-cysteine), carbohydrates (sucrose, D-glucose, maltose), organic acids (L-ascorbic acid, citric acid, DL-malic acid, lactic acid), and sodium sulfite were individually added at different concentrations to a pickling solution to prepare preserved eggs. Lysinoalanine formation as an index of these 10 substances was determined. Results indicate that glutathione, D-glucose, maltose, L-ascorbic acid, citric acid, lactic acid, and sodium sulfite all effectively diminished lysinoalanine formation in preserved egg albumen and yolk. When 40 and 80 mmol/L of sodium sulfite, citric acid, L-ascorbic acid, and D-glucose were individually added into the pickling solution, the inhibition rates of lysinoalanine in the produced preserved egg albumen and yolk were higher. However, the attempt of minimizing lysinoalanine formation was combined with the premise of ensuring preserved eggs quality. Moreover, the addition of 40 and 80 mmol/L of sodium sulfite, 40 and 80 mmol/L of D-glucose, 40 mmol/L of citric acid, and 40 mmol/L of L-ascorbic acid was optimal to produce preserved eggs. The corresponding inhibition rates of lysinoalanine in the albumen were approximately 76.3% to 76.5%, 67.6% to 67.8%, 74.6%, and 74.6%, and the corresponding inhibition rates of lysinoalanine in the yolk were about 68.7% to 69.7%, 50.6% to 51.8%, 70.4%, and 57.8%. It was concluded that sodium sulfite, D-glucose, L-ascorbic, and citric acid at suitable concentrations can be used to control the formation of lysinoalanine during preserved egg processing.

  7. Effects of sulfhydryl compounds, carbohydrates, organic acids, and sodium sulfite on the formation of lysinoalanine in preserved egg.

    PubMed

    Luo, Xu-Ying; Tu, Yong-Gang; Zhao, Yan; Li, Jian-Ke; Wang, Jun-Jie

    2014-08-01

    To identify inhibitors for lysinoalanine formation in preserved egg, sulfhydryl compounds (glutathione, L-cysteine), carbohydrates (sucrose, D-glucose, maltose), organic acids (L-ascorbic acid, citric acid, DL-malic acid, lactic acid), and sodium sulfite were individually added at different concentrations to a pickling solution to prepare preserved eggs. Lysinoalanine formation as an index of these 10 substances was determined. Results indicate that glutathione, D-glucose, maltose, L-ascorbic acid, citric acid, lactic acid, and sodium sulfite all effectively diminished lysinoalanine formation in preserved egg albumen and yolk. When 40 and 80 mmol/L of sodium sulfite, citric acid, L-ascorbic acid, and D-glucose were individually added into the pickling solution, the inhibition rates of lysinoalanine in the produced preserved egg albumen and yolk were higher. However, the attempt of minimizing lysinoalanine formation was combined with the premise of ensuring preserved eggs quality. Moreover, the addition of 40 and 80 mmol/L of sodium sulfite, 40 and 80 mmol/L of D-glucose, 40 mmol/L of citric acid, and 40 mmol/L of L-ascorbic acid was optimal to produce preserved eggs. The corresponding inhibition rates of lysinoalanine in the albumen were approximately 76.3% to 76.5%, 67.6% to 67.8%, 74.6%, and 74.6%, and the corresponding inhibition rates of lysinoalanine in the yolk were about 68.7% to 69.7%, 50.6% to 51.8%, 70.4%, and 57.8%. It was concluded that sodium sulfite, D-glucose, L-ascorbic, and citric acid at suitable concentrations can be used to control the formation of lysinoalanine during preserved egg processing. PMID:25047093

  8. An evaluation of Pt sulfite acid (PSA) as precursor for supported Pt catalysts

    SciTech Connect

    Regalbuto, J.R.; Ansel, O.; Miller, J.T.

    2010-11-12

    As a catalyst precursor, platinum sulfite acid (PSA) is easy to use and not relatively expensive, and is a potentially attractive precursor for many types of supported catalysts. The ultimate usefulness for many catalyst applications will depend on the extent that Pt can be dispersed and sulfur eliminated. To our knowledge, there exists no detailed characterization in the catalysis literature of PSA and the nanoparticulate Pt phases derived from it during catalyst pretreatment. To this end a series of supports including alumina, silica, magnesia, niobia, titania, magnesia and carbon were contacted with PSA solutions and subsequently analyzed with extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) analysis, and x-ray photoelectron spectroscopy (XPS) to characterize the Pt species formed upon impregnation, calcination, and reduction. While all catalysts show retention of some S, reasonably small particle sizes with relatively little Pt-S can in some instances be produced using PSA. The amount of retained sulfur appears to decrease with decreasing surface acidity, although even the most acidic supports (niobia and silica) display some storage of S even while only Pt-O bands are observed after calcination or reoxidation. More sulfur was eliminated by high temperature calcinations followed by reduction in hydrogen, at the expense of increasing Pt particle size.

  9. Kinetics of the reduction of vanadium(V) by sodium sulfite in an acidic medium

    SciTech Connect

    Khyarsing, I.V.; Filippov, A.P.

    1983-01-01

    The kinetics of the reduction of vanadium(V) by sodium sulfite was studied by uv-visible spectrometry at 25/sup 0/C. The acidity of the solutions was controlled by the addition of calculated amounts of hydrochloric, sulfuric acids and sodium hydroxide. The pH of the medium varied from -0.45 to 3. The reagents were mixed, remained thermostated for 20 min; and the optical density vs time was recorded with a Specord uv vis spectrophotometer. Rate curves were measured in the absorption region of vanadium(V) and vanadium(IV). The light absorption followed the Lambert-Berr-Bouguer law. The effective rate constant was calculated from the change in optical density in the region of vanadium(IV) absorption. The most active species appear to be HSO/sub 3//sup -/ and VO/sub 2/SO/sub 4//sup -/. Above pH 3, the reaction is accompanied by a slow increase in optical density over the entire visible spectrum, and after a period of time these solutions deposit a green precipitate which is, apparently a polymeric vanadyl vanadate. 3 figures, 2 tables.

  10. Carbon nanodots sensitized chemiluminescence on peroxomonosulfate-sulfite-hydrochloric acid system and its analytical applications.

    PubMed

    Zhou, Yun; Xing, Gaowa; Chen, Hui; Ogawa, Nobuaki; Lin, Jin-Ming

    2012-09-15

    In the present work, new water-soluble fluorescent carbon nanodots (C-dots) were prepared in a facile microwave pyrolysis approach in minutes by combining glycine and polyethylene glycol 200 (PEG 200). Transmission electron microscopy (TEM) measurements showed that the resulting C-dots had diameters of about 3 nm. (13)C NMR spectra further confirmed the presence of carbons (sp(2) and sp(3)) indicating a nanocrystalline core of the resulting C-dots with hydroxyl of PEG 200 covered outside. It was discovered that the prepared C-dots could dramatically enhance the chemiluminescence (CL) intensity of potassium peroxomonosulfate-sodium sulfite-hydrochloric acid (PSHA) reactions. UV-vis absorption and photoluminescence (PL) spectra indicated that the C-dots sensitized enhancements originated from their energy transfer and electron-transfer annihilation effects on the CL system. When the concentration of C-dots was 4×10(-5) M, and those of KHSO(5), Na(2)SO(3) and HCl were 1×10(-2) M, an excellent performance was obtained. The C-dots sensitized CL system was successfully applied to the determination of aliphatic primary amines in real water samples with satisfactory results. PMID:22967581

  11. Optimization of sulfide/sulfite pretreatment of lignocellulosic biomass for lactic acid production.

    PubMed

    Idrees, Muhammad; Adnan, Ahmad; Qureshi, Fahim Ashraf

    2013-01-01

    Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC), bagasse (BG), water hyacinth and rice husk (RH) for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na₂S and Na₂SO₃, which had high coefficient of determination (R²) along with low probability value (P), indicating the reliable predictability of the model. At optimized conditions, Na₂S and Na₂SO₃ remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93%) during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na₂S at 130°C for 2.3-3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na₂SO₃ showed higher hydrolysis yield (86.34%) as compared to Na₂S while other biomass substrates showed 2.0-3.0% less yield with Na₂SO₃. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL⁻¹ of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively. PMID:24058918

  12. Optimization of Sulfide/Sulfite Pretreatment of Lignocellulosic Biomass for Lactic Acid Production

    PubMed Central

    Adnan, Ahmad; Qureshi, Fahim Ashraf

    2013-01-01

    Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC), bagasse (BG), water hyacinth and rice husk (RH) for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na2S and Na2SO3, which had high coefficient of determination (R2) along with low probability value (P), indicating the reliable predictability of the model. At optimized conditions, Na2S and Na2SO3 remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93%) during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na2S at 130°C for 2.3–3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na2SO3 showed higher hydrolysis yield (86.34%) as compared to Na2S while other biomass substrates showed 2.0–3.0% less yield with Na2SO3. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL−1 of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively. PMID:24058918

  13. Concentrated sulfite-yeast fermenting mixture as a corrosion inhibitor of copper in mixtures of sulfuric and nitric acid

    SciTech Connect

    Agaev, N.M.; Smorodin, A.E.; Rzaev, E.R.; Tyr, S.G.; Shlimak, Ya.B.; Geidarova, G.D.; Eremeeva, R.A.; Nasirov, G.N.

    1987-03-01

    At the Baku factory of residential air conditioning systems both preliminary and final pickling of copper tubing is carried out in a solution of sulfuric and nitric acids. The authors of this study, in seeking an inhibitor to control this process, evaluate the protective properties of an inhibitor based on a concentrated sulfite-yeast fermenting mixture that is generated as a common waste product by the cellulose-pulp industry. It consists of calcium, sodium, and ammonium salts of lignin sulfonic acids. Tests revealed not only its inhibiting effectiveness but also its capacity to lower toxic gas levels of nitrogen oxides in the plant environment.

  14. Thermochemical Reduction Experiments of Native Sulfur, Sulfite, and Sulfate by Amino Acids at 150 - 200°C

    NASA Astrophysics Data System (ADS)

    Naraoka, H.; Watanabe, Y.; Ohmoto, H.

    2006-12-01

    We have conducted series of laboratory experiments to investigate geochemical characteristics (e.g., kinetics and sulfur isotope fractionations) of redox reactions between a variety of amino acids (alanine, glycine, hystidine, etc.) and native sulfur, sodium sulfite or sodium sulfate at 150 - 200°C. While previous researchers failed to demonstrate thermochemical sulfate reduction (TSR) at temperatures below 230°C using a variety of organic compounds (sugars, methane, xylene, etc), in our series of experiments, all S-species were reduced to H2S by amino acids without presence of initial H2S and at neutral pH (i.e., pH = 6) even at 150°C. The reduction rates generally decreased: (a) from native sulfur, to sulfite, and to sulfate; (b) from simple amino acids to more complex amino acids, particularly with aromatic functional groups (e.g., histidine); and (c) with decreasing temperatures. The rates of sulfite and S0 reduction were, respectively, approximately 2 and 3 orders of magnitude faster than those of sulfate. The kinetic isotope effects (Δ34S = δ34SH2S - δ34Sreactant) generally increased with increasing valence of the starting S-compounds. However, they have very complex trends for particularly experiments using sulfate. They fluctuated between positive and negative in others, and continued to increase or decrease in some runs up to +10 or -10 per mil. These variations likely associated with changes in S/C ratios of initial mixtures, and probably occurred because the generation of reductants (i.e., CH4, H2, and NH4+) from the solid mixtures varied; the kinetic isotope effects associated with sulfate reduction by NH4+ may be quite different from those associated with reduction by H2 and/or CH4. The Δ^{33}S values of run products (H2S) generally increased from +0.16 per mil to +0.61 per mil with decreasing rates of sulfate reduction.

  15. 2,4,6-trinitrophenyl-amino acid derivatives as spectrophotometric reagents for sulfur dioxide. [Using sodium sulfite

    SciTech Connect

    Al-Hajjaji, M.A.

    1984-01-01

    A spectrophotometric method for sulfur dioxide determination was explored on the basis of its complexation with TNP-amino acid derivatives forming an orange colored 1:1 complex with an increase in absorbance at 420 nm. TNP-glycine, TNP-threonine, TNP-serine and TNP-histidine (TNP-(2,4,6-trinitrophenyl-)) were investigated. The color development was instantaneous and the absorbance remained unchanged even after 24 h of mixing when kept in the dark. Linear calibration graphs (0-5 x 10/sup -5/M sulfite ions) were obtained at optimal reaction conditions of 7 x 10/sup -5/M TNP-amino acid and pH 8.0 phosphate buffer (0.05 M). The investigation of the effect of several diverse ions revealed an interference by sulfide and mercury ions at concentration levels of 10/sup -4/M. The standard deviation of determining 3 x 10/sup -5/M sulfite solution (10 times) was 1.474 x 10/sup -7/M. 22 references, 2 figures, 1 table.

  16. Sulfite oxidizing enzymes

    PubMed Central

    Feng, Changjian; Tollin, Gordon; Enemark, John H.

    2007-01-01

    Sulfite oxidizing enzymes are essential mononuclear molybdenum (Mo) proteins involved in sulfur metabolism of animals, plants and bacteria. There are three such enzymes presently known: (1) sulfite oxidase (SO) in animals, (2) SO in plants, and (3) sulfite dehydrogenase (SDH) in bacteria. X-ray crystal structures of enzymes from all three sources (chicken SO, Arabidopsis thaliana SO, and Starkeya novella SDH) show nearly identical square pyramidal coordination around the Mo atom, even though the overall structures of the proteins and the presence of additional cofactors vary. This structural information provides a molecular basis for studying the role of specific amino acids in catalysis. Animal SO catalyzes the final step in the degradation of sulfur-containing amino acids and is critical in detoxifying excess sulfite. Human SO deficiency is a fatal genetic disorder that leads to early death, and impaired SO activity is implicated in sulfite neurotoxicity. Animal SO and bacterial SDH contain both Mo and heme domains, whereas plant SO only has the Mo domain. Intraprotein electron transfer (IET) between the Mo and Fe centers in animal SO and bacterial SDH is a key step in the catalysis, which can be studied by laser flash photolysis in the presence of deazariboflavin. IET studies on animal SO and bacterial SDH clearly demonstrate the similarities and differences between these two types of sulfite oxidizing enzymes. Conformational change is involved in the IET of animal SO, in which electrostatic interactions may play a major role in guiding the docking of the heme domain to the Mo domain prior to electron transfer. In contrast, IET measurements for SDH demonstrate that IET occurs directly through the protein medium, which is distinctly different from that in animal SO. Point mutations in human SO can result in significantly impaired IET or no IET, thus rationalizing their fatal effects. The recent developments in our understanding of sulfite oxidizing enzyme

  17. Comparison of dilute acid and sulfite pretreatments on Acacia confusa for biofuel application and the influence of its extractives.

    PubMed

    Yeh, Ting-Feng; Chang, Mao-Ju; Chang, Wan-Jung

    2014-11-01

    Chemical components of lignocellulosic biomass may impede biofuel processing efficiency. To understand whether the heartwood of Acacia confusa is suitable for biofuel application, extractive-free heartwood of A. confusa was subjected to dilute acid (DA) or sulfite pretreatments. Sugar recoveries were used to evaluate the performance of different pretreatments. Cell wall properties, such as 4-O-alkylated lignin structures, S/G ratios, and xylan contents, of the pretreated samples showed significant correlations with the enzymatic saccharification of glucan. The 4% bisulfite-pretreated samples produced higher total sugar recoveries than DA-treated samples. The highest total sugar recoveries from DA and sulfite pretreatment were 52.0% (170 °C for 20 min) and 65.3% (4% NaHSO3 and 1% H2SO4), respectively. The results also demonstrated that the existence of extractives in the heartwood of A. confusa hindered the sugar recoveries from both the pretreatments and enzymatic saccharification. Total sugar recoveries were reduced 11.7-17.7% in heartwood samples with extractives.

  18. Comparison of bamboo green, timber and yellow in sulfite, sulfuric acid and sodium hydroxide pretreatments for enzymatic saccharification.

    PubMed

    Li, Zhiqiang; Jiang, Zehui; Fei, Benhua; Cai, Zhiyong; Pan, Xuejun

    2014-01-01

    The response and behavior of bamboo green, timber, and yellow of moso bamboo (Phyllostachys heterocycla) to three pretreatments, sulfite (SPORL), dilute acid (DA), and alkali (NaOH), were investigated and compared with varied chemical loadings at 180°C for 30 min with a 6.25:1 (v/w) liquor-to-bamboo ratio. All the pretreatments improved the enzymatic digestibility of bamboo substrates. Under the investigated conditions, the DA pretreatment achieved better enzymatic digestibility, but had lower sugar recovery yield, and formed more fermentation inhibitors. The results suggested that the SPORL pretreatment be able to generate more readily digestible bamboo substrate with higher sugar yield and fewer fermentation inhibitors than the corresponding DA pretreatment if hemicelluloses are sufficiently removed by adding more acid to bring down the pretreatment pH. Bamboo timber had higher sugar content and better enzymatic digestibility and therefore was a better feedstock for bioconversion than bamboo green and yellow.

  19. Mutants of the pentose-fermenting yeast Pachysolen tannophilus tolerant to hardwood spent sulfite liquor and acetic acid.

    PubMed

    Harner, Nicole K; Bajwa, Paramjit K; Habash, Marc B; Trevors, Jack T; Austin, Glen D; Lee, Hung

    2014-01-01

    A strain development program was initiated to improve the tolerance of the pentose-fermenting yeast Pachysolen tannophilus to inhibitors in lignocellulosic hydrolysates. Several rounds of UV mutagenesis followed by screening were used to select for mutants of P. tannophilus NRRL Y2460 with improved tolerance to hardwood spent sulfite liquor (HW SSL) and acetic acid in separate selection lines. The wild type (WT) strain grew in 50 % (v/v) HW SSL while third round HW SSL mutants (designated UHW301, UHW302 and UHW303) grew in 60 % (v/v) HW SSL, with two of these isolates (UHW302 and UHW303) being viable and growing, respectively, in 70 % (v/v) HW SSL. In defined liquid media containing acetic acid, the WT strain grew in 0.70 % (w/v) acetic acid, while third round acetic acid mutants (designated UAA301, UAA302 and UAA303) grew in 0.80 % (w/v) acetic acid, with one isolate (UAA302) growing in 0.90 % (w/v) acetic acid. Cross-tolerance of HW SSL-tolerant mutants to acetic acid and vice versa was observed with UHW303 able to grow in 0.90 % (w/v) acetic acid and UAA302 growing in 60 % (v/v) HW SSL. The UV-induced mutants retained the ability to ferment glucose and xylose to ethanol in defined media. These mutants of P. tannophilus are of considerable interest for bioconversion of the sugars in lignocellulosic hydrolysates to ethanol.

  20. Mass independent fractionation of sulfur isotopes during thermochemical reduction of native sulfur, sulfite and sulfate by amino acids

    NASA Astrophysics Data System (ADS)

    Watanabe, Y.; Naraoka, H.; Ohmoto, H.

    2006-05-01

    Mass independent fractionation of sulfur isotopes (MIF-S) is recognized when the Δ33S value (= δ33S-0.515xδ34S) of a sample falls outside the range of 0±0.2 permil and the 33-34θ value (= ln33α/ ln34α) lies outside the range of 0.515±.005 (Farquhar and Wing, 2003). Previous investigators have concluded that the only mechanisms to create MIF-S are photochemical reactions between sulfur-bearing gases (SO2, H2S) and UV. Based on comparisons of the geochemical characteristics of Archean sedimentary rocks between those with large MIF-S values (e.g., the 2.5 Ga McRae and 2.7 Ga Jeerinah shales) and those with no (or very small) MIF- S values (e.g., 2.76 Ga Hardey shales and 2.92 Ga Mosquito Creek shales), we have developed a hypothesis that MIF-S in sedimentary rocks may have been created by reactions among organic-rich sediments, sulfur- bearing solid compounds, and sulfur-bearing hydrothermal fluids at T = 100-200°C during the early diagenetic stage of sediments. Most abundant organic compounds in immature sediments are amino acids. For these reasons, we have conducted series of laboratory experiments to investigate sulfur isotope fractionations during reactions between a variety of amino acids (alanine, glycine, hystidine, etc.) and native sulfur, sodium sulfite or sodium sulfate at 150-200°C. Previous researchers used a variety of organic compounds (sugars, methane, xylene, etc) and/or ferrous- bearing minerals to investigate non-bacterial sulfate reduction, but they failed to demonstrate thermochemical sulfate reduction at temperatures below 230°C. However, we were able to reduce sulfate (S6+), as well as sulfite (S4+) and native sulfur (S0), to hydrogen sulfide (S2-) even at 150°C using simple and common amino acids (e.g., alanine and glycine). The reduction rates generally decreased: (a) from native sulfur, to sulfite, and to sulfate; (b) from simple amino acids to more complex amino acids (e.g., histidine); and (c) with decreasing temperatures. The

  1. Effect of sodium sulfite, carboxylic monomer, and phosphoric acid etching on bonding of tri-n-butylborane initiated resin to human enamel.

    PubMed

    Nogawa, Hiroshi; Koizumi, Hiroyasu; Akazawa, Nobutaka; Hiraba, Haruto; Nakamura, Mitsuo; Matsumura, Hideo

    2015-03-01

    The purpose of the present study is evaluation of bonding durability of tri-n-butylborane (TBB) initiated resin without 4-methacryloyloxyethyl trimellitate anhydride (4-META) joined to human enamel. Ground human enamel was bonded with TBB resin under six surface conditions: 1) as ground, 2) primed with Teeth Primer, 3) sodium sulfite solution, 4) 4-META solution, 5) acetone-water, and 6) phosphoric acid etching. Pre- and post-thermocycling bond strengths and change in strength after thermocycling were compared. Etching enamel with 35-45% phosphoric acid enhanced bonding durability between enamel and TBB-initiated resin. Priming with Teeth Primer or 4-META solution improved bond strength between enamel and TBB-initiated resin. Sodium sulfite had little effect on enamel bonding in the present bonding systems. PMID:25807904

  2. Isolation and characterization of acetic acid-tolerant galactose-fermenting strains of Saccharomyces cerevisiae from a spent sulfite liquor fermentation plant.

    PubMed Central

    Lindén, T; Peetre, J; Hahn-Hägerdal, B

    1992-01-01

    From a continuous spent sulfite liquor fermentation plant, two species of yeast were isolated, Saccharomyces cerevisiae and Pichia membranaefaciens. One of the isolates of S. cerevisiae, no. 3, was heavily flocculating and produced a higher ethanol yield from spent sulfite liquor than did commercial baker's yeast. The greatest difference between isolate 3 and baker's yeast was that of galactose fermentation, even when galactose utilization was induced, i.e., when they were grown in the presence of galactose, prior to fermentation. Without acetic acid present, both baker's yeast and isolate 3 fermented glucose and galactose sequentially. Galactose fermentation with baker's yeast was strongly inhibited by acetic acid at pH values below 6. Isolate 3 fermented galactose, glucose, and mannose without catabolite repression in the presence of acetic acid, even at pH 4.5. The xylose reductase (EC 1.1.1.21) and xylitol dehydrogenase (EC 1.1.1.9) activities were determined in some of the isolates as well as in two strains of S. cerevisiae (ATCC 24860 and baker's yeast) and Pichia stipitis CBS 6054. The S. cerevisiae strains manifested xylose reductase activity that was 2 orders of magnitude less than the corresponding P. stipitis value of 890 nmol/min/mg of protein. The xylose dehydrogenase activity was 1 order of magnitude less than the corresponding activity of P. stipitis (330 nmol/min/mg of protein). Images PMID:1622236

  3. Structural Insights into Sulfite Oxidase Deficiency

    SciTech Connect

    Karakas,E.; Wilson, H.; Graf, T.; Xiang, S.; Jaramillo-Busquets, S.; Rajagopalan, K.; Kisker, C.

    2005-01-01

    Sulfite oxidase deficiency is a lethal genetic disease that results from defects either in the genes encoding proteins involved in molybdenum cofactor biosynthesis or in the sulfite oxidase gene itself. Several point mutations in the sulfite oxidase gene have been identified from patients suffering from this disease worldwide. Although detailed biochemical analyses have been carried out on these mutations, no structural data could be obtained because of problems in crystallizing recombinant human and rat sulfite oxidases and the failure to clone the chicken sulfite oxidase gene. We synthesized the gene for chicken sulfite oxidase de novo, working backward from the amino acid sequence of the native chicken liver enzyme by PCR amplification of a series of 72 overlapping primers. The recombinant protein displayed the characteristic absorption spectrum of sulfite oxidase and exhibited steady state and rapid kinetic parameters comparable with those of the tissue-derived enzyme. We solved the crystal structures of the wild type and the sulfite oxidase deficiency-causing R138Q (R160Q in humans) variant of recombinant chicken sulfite oxidase in the resting and sulfate-bound forms. Significant alterations in the substrate-binding pocket were detected in the structure of the mutant, and a comparison between the wild type and mutant protein revealed that the active site residue Arg-450 adopts different conformations in the presence and absence of bound sulfate. The size of the binding pocket is thereby considerably reduced, and its position relative to the cofactor is shifted, causing an increase in the distance of the sulfur atom of the bound sulfate to the molybdenum.

  4. A novel photochemical system of ferrous sulfite complex: kinetics and mechanisms of rapid decolorization of Acid Orange 7 in aqueous solutions.

    PubMed

    Zhou, Danna; Chen, Long; Zhang, Changbo; Yu, Yingtan; Zhang, Li; Wu, Feng

    2014-06-15

    We previously reported the decolorization of the azo dye Acid Orange 7 (AO7) by sulfate radical (SO4(-)) in the presence of iron(II) sulfite complex and oxygen under UV-vis irradiation (photo-iron(II) sulfite system). This system, however, achieves very limited mineralization of AO7 (in terms of total organic carbon (TOC) removal), which is not in accordance with literature reports on the oxidation of organic contaminants by SO4(-). In the present work, kinetics and products under irradiation of xenon lamp (350 W) were analyzed to reveal the reaction pathway of decolorization of AO7. Steady-state approximation (SSA) of SO4(-) radicals and apparent kinetics of AO7 were examined. The reaction between AO7 and SO4(-) was found to proceed in two steps, namely, electron transfer and SO4(-) addition. The second-order rate constant for the reaction between AO7 and SO4(-) was found to be 8.07 ± 1.07 × 10(9) M(-1) s(-1) by SSA and 6.80 ± 0.68 × 10(9) M(-1) s(-1) by competition kinetics method. The apparent kinetics of the decolorization of AO7 under irradiation closely fits the mechanism of radical chain reactions of various reactive sulfur species. By liquid chromatography coupled with mass spectrometry, we identified the sulfate adduct AO7-SO4 and confirmed the two-step reaction between AO7 and SO4(-). This stable sulfate adduct provides a good explanation of the poor TOC removal during decolorization of AO7 by the photo-iron(II) sulfite system.

  5. Sulfite hypersensitivity. A critical review

    SciTech Connect

    Gunnison, A.F.; Jacobsen, D.W.

    1987-01-01

    Sulfiting agents (sulfur dioxide and the sodium and potassium salts of bisulfite, sulfite, and metabisulfite) are widely used as preservatives in foods, beverages, and pharmaceuticals. Within the past 5 years, there have been numerous reports of adverse reactions to sulfiting agents. This review presents a comprehensive compilation and discussion of reports describing reactions to ingested, inhaled, and parenterally administered sulfite. Sulfite hypersensitivity is usually, but not exclusively, found within the chronic asthmatic population. Although there is some disagreement on its prevalence, a number of studies have indicated that 5 to 10% of all chronic asthmatics are sulfite hypersensitive. This review also describes respiratory sulfur dioxide sensitivity which essentially all asthmatics experience. Possible mechanisms of sulfite hypersensitivity and sulfur dioxide sensitivity are discussed in detail. Sulfite metabolism and the role of sulfite oxidase in the detoxification of exogenous sulfite are reviewed in relationship to the etiology of sulfite hypersensitivity. 147 references.

  6. Hippocampal neuron number loss in rats exposed to ingested sulfite.

    PubMed

    Akdogan, Ilgaz; Kocamaz, Erdogan; Kucukatay, Vural; Yonguc, Nilufer Goksin; Ozdemir, Mehmet Bulent; Murk, William

    2011-10-01

    Sulfite, which is continuously formed in the body during metabolism of sulfur-containing amino acids, is commonly used in preservatives. It has been shown that there are toxic effects of sulfite on many cellular components. The aim of this study was to investigate the possible toxic effects of sulfite on pyramidal neurons by counting cell numbers in CA1 and CA2-CA3 subdivisions of the rat hippocampus. For this purpose, male albino rats were divided into a control group and a sulfite group (25 mg/kg). Sulfite was administered to the animals via drinking water for 8 weeks. At the end of the experimental period, brains were removed and neurons were estimated in total and in a known fraction of CA1 and CA2-CA3 subdivisions of the left hippocampus by using the optical fractionator method--a stereological method. Results showed that sulfite treatment caused a significant decrease in the total number of pyramidal neurons in three subdivisions of the hippocampus (CA1 and CA2-CA3) in the sulfite group compared with the control group (p < 0.05, Mann Whitney U test). It was concluded that exogenous administration of sulfite causes loss of pyramidal neurons in CA1 and CA2-CA3 subdivisions of the rat hippocampus.

  7. Molecular Basis for Enzymatic Sulfite Oxidation

    PubMed Central

    Bailey, Susan; Rapson, Trevor; Johnson-Winters, Kayunta; Astashkin, Andrei V.; Enemark, John H.; Kappler, Ulrike

    2009-01-01

    Sulfite dehydrogenases (SDHs) catalyze the oxidation and detoxification of sulfite to sulfate, a reaction critical to all forms of life. Sulfite-oxidizing enzymes contain three conserved active site amino acids (Arg-55, His-57, and Tyr-236) that are crucial for catalytic competency. Here we have studied the kinetic and structural effects of two novel and one previously reported substitution (R55M, H57A, Y236F) in these residues on SDH catalysis. Both Arg-55 and His-57 were found to have key roles in substrate binding. An R55M substitution increased Km(sulfite)(app) by 2–3 orders of magnitude, whereas His-57 was required for maintaining a high substrate affinity at low pH when the imidazole ring is fully protonated. This effect may be mediated by interactions of His-57 with Arg-55 that stabilize the position of the Arg-55 side chain or, alternatively, may reflect changes in the protonation state of sulfite. Unlike what is seen for SDHWT and SDHY236F, the catalytic turnover rates of SDHR55M and SDHH57A are relatively insensitive to pH (∼60 and 200 s–1, respectively). On the structural level, striking kinetic effects appeared to correlate with disorder (in SDHH57A and SDHY236F) or absence of Arg-55 (SDHR55M), suggesting that Arg-55 and the hydrogen bonding interactions it engages in are crucial for substrate binding and catalysis. The structure of SDHR55M has sulfate bound at the active site, a fact that coincides with a significant increase in the inhibitory effect of sulfate in SDHR55M. Thus, Arg-55 also appears to be involved in enabling discrimination between the substrate and product in SDH. PMID:19004819

  8. Factors supporting cysteine tolerance and sulfite production in Candida albicans.

    PubMed

    Hennicke, Florian; Grumbt, Maria; Lermann, Ulrich; Ueberschaar, Nico; Palige, Katja; Böttcher, Bettina; Jacobsen, Ilse D; Staib, Claudia; Morschhäuser, Joachim; Monod, Michel; Hube, Bernhard; Hertweck, Christian; Staib, Peter

    2013-04-01

    The amino acid cysteine has long been known to be toxic at elevated levels for bacteria, fungi, and humans. However, mechanisms of cysteine tolerance in microbes remain largely obscure. Here we show that the human pathogenic yeast Candida albicans excretes sulfite when confronted with increasing cysteine concentrations. Mutant construction and phenotypic analysis revealed that sulfite formation from cysteine in C. albicans relies on cysteine dioxygenase Cdg1, an enzyme with similar functions in humans. Environmental cysteine induced not only the expression of the CDG1 gene in C. albicans, but also the expression of SSU1, encoding a putative sulfite efflux pump. Accordingly, the deletion of SSU1 resulted in enhanced sensitivity of the fungal cells to both cysteine and sulfite. To study the regulation of sulfite/cysteine tolerance in more detail, we screened a C. albicans library of transcription factor mutants in the presence of sulfite. This approach and subsequent independent mutant analysis identified the zinc cluster transcription factor Zcf2 to govern sulfite/cysteine tolerance, as well as cysteine-inducible SSU1 and CDG1 gene expression. cdg1Δ and ssu1Δ mutants displayed reduced hypha formation in the presence of cysteine, indicating a possible role of the newly proposed mechanisms of cysteine tolerance and sulfite secretion in the pathogenicity of C. albicans. Moreover, cdg1Δ mutants induced delayed mortality in a mouse model of disseminated infection. Since sulfite is toxic and a potent reducing agent, its production by C. albicans suggests diverse roles during host adaptation and pathogenicity.

  9. Labile sulfide and sulfite in phytochelatin complexes

    SciTech Connect

    Eannetta, N.T.; Steffens, J.C. )

    1989-04-01

    Heavy metals such as cadmium induce tomato cell cultures to synthesize the metal binding polypeptides ({gamma}-Glu-Cys){sub 3} and ({gamma}-Glu-Cys){sub 4}-Gly (phytochelatins). Tomato cells selected for growth on normally lethal concentrations of CdCl{sub 2} synthesize higher quantities of these polypeptides. Cd{sup r} cells are not cross-resistant to other heavy metals, and recent work suggests that metal detoxification by these peptides may be Cd-specific. The occurrence of labile sulfur as a component of the metal complex raises questions concerning possible functions of phytochelatins besides that of Cd binding. The presence of acid-labile sulfide ion in phytochelatin complexes has been reported by several groups. We report the additional finding that labile sulfite is also present in these complexes and in higher amounts than sulfide. Sulfide and sulfite are both released from the metal binding complex by acidification or by treatment with EDTA.

  10. Evaluation of microbial diversity in sulfite-added and sulfite-free wine by culture-dependent and -independent methods.

    PubMed

    Takahashi, Masayuki; Ohta, Tami; Masaki, Kazuo; Mizuno, Akihiro; Goto-Yamamoto, Nami

    2014-05-01

    The difference in microbiota including non-lactic acid bacteria, non-acetic acid bacteria, and wild yeast during winemaking and in the end-products between sulfite-added and sulfite-free wine, was investigated using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and a culture-dependent method. There were differences between the microorganisms detected by PCR-DGGE and those detected by the culture-dependent method, probably because of the selectivity of culture medium and the characteristics of PCR-based method. In both the red wine and white wine, the microbial diversity of the sulfite-added wine was lower than that of the sulfite-free wine during fermentation. Tatumella terrea was detected from the fermenting must by PCR-DGGE and by the culture-dependent method, even though sulfite inhibited its growth to some extent. We confirmed that the addition of sulfite plays an important role in winemaking by inhibiting the growth of unexpected microorganisms, but on the other hand, it was revealed that some microorganisms can survive and grow in sulfite-added fermenting must. We also analyzed 15 samples of commercial wines by the PCR-DGGE method and detected various microorganisms. Among them, Sphingomonas sp., Pseudozyma sp., Ochromonas sp. and Methylophilus sp. were found for the first time in wine as far as we know. We did not identify a specific microorganism that was detected only from wines without sulfite addition. Thus, the microbiota of end-products seemed to be influenced by other factors, such as filtration before bottling, the production equipment and the storage environment.

  11. Sulfite leads to neuron loss in the hippocampus of both normal and SOX-deficient rats.

    PubMed

    Kocamaz, Erdogan; Adiguzel, Esat; Er, Buket; Gundogdu, Gulşah; Kucukatay, Vural

    2012-08-01

    Sulfites are compounds commonly used as preservatives in foods, beverages and pharmaceuticals. Sulfite is also endogenously generated during the metabolism of sulfur-containing amino acids and drugs. It has been shown that sulfite is a highly toxic molecule. Many studies have examined the effects of sulfite toxicity, but the effect of ingested sulfite on the number of neurons in the hippocampus has not yet been reported. The present study was undertaken to investigate the effect of ingested sulfite on pyramidal neurons by counting cells in CA1 and CA3-2 subdivisions of the rat hippocampus. For this purpose, rats were assigned to one of four groups (6 rats per group): control (C), sulfite (S), deficient (D) and deficient+sulfite (DS). Sulfite oxidase deficiency was established by feeding rats a low molybdenum diet and adding 200ppm tungsten (W) to their drinking water. Sulfite (70mg/kg) was also administered to the animals via their drinking water. At the end of the experimental period, the rats were sacrificed by exsanguination under anesthesia, and their brains and livers quickly removed. The livers were used for a SOX activity assay, and the brains were used for neuronal counts in a known fraction of the CA1 and CA3-2 subdivisions of the left hippocampus using the optical fractionator method, which is a stereological method. The results showed that sulfite treatment caused a significant decrease in the total number of pyramidal neurons in three subdivisions of the hippocampus (CA1 and CA3-2) in the S, D and DS groups compared with the control group. It is concluded that exogenous administration of sulfite causes loss of pyramidal neurons in CA1 and CA3-2 subdivisions in both normal and SOX deficient rat hippocampus. This finding provides supporting evidence that sulfite is a neurotoxic molecule.

  12. Comparative study of sulfite pretreatments for robust enzymatic saccharification of corn cob residue

    PubMed Central

    2012-01-01

    Background Corn cob residue (CCR) is a kind of waste lignocellulosic material with enormous potential for bioethanol production. The moderated sulphite processes were used to enhance the hydrophily of the material by sulfonation and hydrolysis. The composition, FT-IR spectra, and conductometric titrations of the pretreated materials were measured to characterize variations of the CCR in different sulfite pretreated environments. And the objective of this study is to compare the saccharification rate and yield of the samples caused by these variations. Results It was found that the lignin in the CCR (43.2%) had reduced to 37.8%, 38.0%, 35.9%, and 35.5% after the sulfite pretreatment in neutral, acidic, alkaline, and ethanol environments, respectively. The sulfite pretreatments enhanced the glucose yield of the CCR. Moreover, the ethanol sulfite sample had the highest glucose yield (81.2%, based on the cellulose in the treated sample) among the saccharification samples, which was over 10% higher than that of the raw material (70.6%). More sulfonic groups and weak acid groups were produced during the sulfite pretreatments. Meanwhile, the ethanol sulfite treated sample had the highest sulfonic group (0.103 mmol/g) and weak acid groups (1.85 mmol/g) in all sulfite treated samples. In FT-IR spectra, the variation of bands at 1168 and 1190 cm-1 confirmed lignin sulfonation during sulfite pretreatment. The disappearance of the band at 1458 cm-1 implied the methoxyl on lignin had been removed during the sulfite pretreatments. Conclusions It can be concluded that the lignin in the CCR can be degraded and sulfonated during the sulfite pretreatments. The pretreatments improve the hydrophility of the samples because of the increase in sulfonic group and weak acid groups, which enhances the glucose yield of the material. The ethanol sulfite pretreatment is the best method for lignin removal and with the highest glucose yield. PMID:23206858

  13. Plant sulfite oxidase as novel producer of H2O2: combination of enzyme catalysis with a subsequent non-enzymatic reaction step.

    PubMed

    Hänsch, Robert; Lang, Christina; Riebeseel, Erik; Lindigkeit, Rainer; Gessler, Arthur; Rennenberg, Heinz; Mendel, Ralf R

    2006-03-10

    Sulfite oxidase (EC 1.8.3.1) from the plant Arabidopsis thaliana is the smallest eukaryotic molybdenum enzyme consisting of a molybdenum cofactor-binding domain but lacking the heme domain that is known from vertebrate sulfite oxidase. While vertebrate sulfite oxidase is a mitochondrial enzyme with cytochrome c as the physiological electron acceptor, plant sulfite oxidase is localized in peroxisomes and does not react with cytochrome c. Here we describe results that identified oxygen as the terminal electron acceptor for plant sulfite oxidase and hydrogen peroxide as the product of this reaction in addition to sulfate. The latter finding might explain the peroxisomal localization of plant sulfite oxidase. 18O labeling experiments and the use of catalase provided evidence that plant sulfite oxidase combines its catalytic reaction with a subsequent non-enzymatic step where its reaction product hydrogen peroxide oxidizes another molecule of sulfite. In vitro, for each catalytic cycle plant SO will bring about the oxidation of two molecules of sulfite by one molecule of oxygen. In the plant, sulfite oxidase could be responsible for removing sulfite as a toxic metabolite, which might represent a means to protect the cell against excess of sulfite derived from SO2 gas in the atmosphere (acid rain) or during the decomposition of sulfur-containing amino acids. Finally we present a model for the metabolic interaction between sulfite and catalase in the peroxisome.

  14. Sulfite-sulfide-sulfate-carbonate equilibria with applications to Mars

    NASA Astrophysics Data System (ADS)

    Marion, G. M.; Kargel, J. S.; Crowley, J. K.; Catling, D. C.

    2013-07-01

    Mars volcanic SO2 and H2S gas emissions are likely the dominant source of martian sulfate, and the source of sulfuric acid. Until this work, the FREZCHEM model lacked SO2 and H2S gases and associated sulfite and sulfide minerals. The specific objectives of this paper were to add these components and associated sulfite and sulfide minerals and phases into FREZCHEM, and to explore some possible roles of these chemistries on Mars. New solid phases added included the sulfites: Na2SO3·7H2O, K2SO3, (NH4)2SO3·H2O, MgSO3·6H2O, CaSO3·0.5H2O, and FeSO3·1.5H2O, and the sulfide: FeS2. The lowest eutectic of these minerals was K2SO3 (= 6.57 m) at 228 K. Because sulfurous acid is stronger than carbonic acid, this causes a much larger fraction of S(IV) to exist as sulfite (SO32-) at acidic to mildly alkaline pH, whereas almost none of the C is present as carbonate anion. Model calculations show that small quantities of SO2 in an early CO2-rich martian atmosphere suppressed formation of carbonates because SO2 is much more water soluble than CO2 and a stronger acid, which may be a major reason why sulfates are much more common than carbonates on Mars. Also, perhaps equally important are low temperatures that favor sulfite mineral precipitation, the oxidation of which leads to sulfate minerals. Another potentially important factor that favors sulfite/sulfide mineral formation is low pH values that cannot allow carbonate minerals, but can allow sulfide minerals such as pyrite (FeS2). The presence of pyrite, highly insoluble, would lead to sulfate minerals when oxygen becomes available in acidic environments. Major cations for both sulfites (or sulfates) and carbonates (Ca and Mg) can limit carbonates. Sulfite-sulfide volcanism on a cold, lower pH, Mars are the primary causes of high sulfate minerals (e.g., Ca and Mg sulfates), compared to volcanism on a warm, higher pH, Earth that led to more abundant carbonate minerals (e.g., Ca and Mg carbonates).

  15. 21 CFR 582.3798 - Sodium sulfite.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Sodium sulfite. (a) Product. Sodium sulfite. (b) (c) Limitations, restrictions, or explanation. This... practice, except that it is not used in meats or in food recognized as source of vitamin B1....

  16. 21 CFR 182.3798 - Sodium sulfite.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium sulfite. 182.3798 Section 182.3798 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3798 Sodium sulfite. (a) Product. Sodium sulfite. (b) (c) Limitations, restrictions, or explanation. This substance...

  17. 21 CFR 582.3798 - Sodium sulfite.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium sulfite. 582.3798 Section 582.3798 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Sodium sulfite. (a) Product. Sodium sulfite. (b) (c) Limitations, restrictions, or explanation....

  18. 21 CFR 182.3798 - Sodium sulfite.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium sulfite. 182.3798 Section 182.3798 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3798 Sodium sulfite. (a) Product. Sodium sulfite. (b) (c) Limitations, restrictions, or explanation. This substance...

  19. 21 CFR 182.3798 - Sodium sulfite.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium sulfite. 182.3798 Section 182.3798 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3798 Sodium sulfite. (a) Product. Sodium sulfite. (b) (c) Limitations, restrictions, or explanation. This substance...

  20. 21 CFR 582.3798 - Sodium sulfite.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium sulfite. 582.3798 Section 582.3798 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Sodium sulfite. (a) Product. Sodium sulfite. (b) (c) Limitations, restrictions, or explanation....

  1. 21 CFR 582.3798 - Sodium sulfite.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium sulfite. 582.3798 Section 582.3798 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Sodium sulfite. (a) Product. Sodium sulfite. (b) (c) Limitations, restrictions, or explanation....

  2. Actinide sulfite tetrahydrate and actinide oxysulfite tetrahydrate

    SciTech Connect

    Baugh, D.; Watt, G.

    1980-07-08

    A compound is prepared that comprises an actinide sulfite tetrahydrate selected from the group consisting of uranium (IV) sulfite tetrahydrate and plutonium (IV) sulfite tetrahydrate. A compound is also prepared that comprises an actinide oxysulfite tetrahydrate selected from the group consisting of uranium (IV) oxysulfite tetrahydrate and plutonium (IV) oxysulfite tetrahydrate

  3. Immunological comparison of sulfite oxidase

    SciTech Connect

    Pollock, V.; Barber, M.J. )

    1991-03-11

    Polyclonal antibodies (rabbit), elicited against FPLC-purified chicken and rat liver sulfite oxidase (SO), have been examined for inhibition and binding to purified chicken (C), rat (R), bovine (B), alligator (A) and shark (S) liver enzymes. Anti-CSO IgG cross-reacted with all five enzymes, with varying affinities, in the order CSO=ASO{gt}RSO{gt}BSO{gt}SSO. Anti-ROS IgG also cross-reacted with all five enzymes in the order RSO{gt}CSO=ASO{gt}BSO{gt}SSO. Anti-CSO IgG inhibited sulfite:cyt. c reductase (S:CR), sulfite:ferricyanide reductase (S:FR) and sulfite:dichlorophenolindophenol reductase (S:DR) activities of CSO to different extents (S:CR{gt}S:FR=S:DR). Similar differential inhibition was found for anti-ROS IgG and RSO S:CR, S:FR and S:DR activities. Anti-CSO IgG inhibited S:CR activities in the order CSO=ASO{much gt}SSO{gt}BSO. RSO was uninhibited. For anti-RSO IgG the inhibition order was RSO{gt}SSO{gt}BSO{gt}ASO. CSO was uninhibited. Anti-CSO and RSO IgGs partially inhibited Chlorella nitrate reductase (NR). Minor cross-reactivity was found for xanthine oxidase. Common antigenic determinants for all five SO's and NR are indicated.

  4. Nitrogen dioxide absorption in aqueous sodium sulfite

    NASA Astrophysics Data System (ADS)

    Shen, Chen Hua

    The Clean Air Act of 1990 requires additional reduction of acid gases, sulfur dioxide, and nitrogen oxides released into the atmosphere from coal-fired electric power plants. In the case of older existing power plants, a possible retrofit strategy is to oxidize nitric oxide (NO, the major constituent of NOsbX in flue gas) to nitrogen dioxide (NOsb2) by the addition of methanol or other hydrocarbons into the duct at an optimum temperature regime. NOsb2 can then be removed by either modifying existing SOsb2 control equipment or by adding a limestone (CaCOsb3) slurry scrubbing process. Limestone reacts with SOsb2 to from CaSOsb3, and the free sulfite (SO{sb3sp{=}}) in the solution is reactive toward NOsb2. The focus of this research is to study the reaction between NOsb2 and aqueous sulfite at elevated temperature and in the presence of gas phase Osb2. The removal of NOsb2 by limestone slurry scrubbing involves the reaction between NOsb2 and SO{sb3sp{=}}, bisulfite (HSO{sb3sp{-}}) and water. The reactions between NOsb2 and SO{sb3sp{=}}/HSO{sb3sp{-}} are first order in both reactants, while the NOsb2-water reaction is second order in NOsb2 concentration. The rate constants of the above reactions and the NOsb2-thiosulfate (Ssb2O{sb3sp{=}}) reaction were determined at 55sp°C. SO{sb3sp{=}} was found to be the most reactive toward NOsb2, while the contribution of chemical reaction still dominated in the absorption of NOsb2 into water. The effect of gas phase SOsb2 and Osb2, and liquid phase additives such as Ssb2O{sb3sp{=}}, Casp{++}, Mgsp{++}, and Clsp{-} on NOsb2 absorption was also investigated. The absorption of NOsb2 catalyzes free radical reactions that lead to sulfite oxidation. A semi-empirical model was proposed to relate the rate of sulfite oxidation to the rate of NOsb2 absorption. Thiosulfate inhibits sulfite oxidation by providing an alternative route for the termination of the free radical reactions, and a fundamental model was derived to quantify the effect

  5. Physicochemical effects on sulfite transformation in a lipid-rich Chlorella sp. strain

    NASA Astrophysics Data System (ADS)

    Liang, Fang; Wen, Xiaobin; Luo, Liming; Geng, Yahong; Li, Yeguang

    2014-11-01

    SO2 is very rapidly hydrated to sulfurous acid in water solution at pH value above 6.0, whereby sulfite is yielded from the disassociation of protons. We aimed to improve the sulfite transformation efficiency and provide a basis for the direct utilization of SO2 from flue gas by a microalgal suspension. Chlorella sp. XQ-20044 was cultured in a medium with 20 mmol/L sodium sulfite under different physicochemical conditions. Under light conditions, sulfite concentration in the algal suspension reduced linearly over time, and was completely converted into sulfate within 8 h. The highest sulfite transformation rate (3.25 mmol/(L·h)) was obtained under the following conditions: 35°C, light intensity of 300 μmol/(m2·s), NaHCO3 concentration of 6 g/L, initial cell density (OD540) of 0.8 and pH of 9-10. There was a positive correlation between sulfite transformation rate and the growth of Chlorella, with the conditions favorable to algal growth giving better sulfite transformation. Although oxygen in the air plays a role in the transformation of SO2- 3 to SO2- 4, the transformation is mainly dependent on the metabolic activity of algal cells. Chlorella sp. XQ-20044 is capable of tolerating high sulfite concentration, and can utilize sulfite as the sole sulfur source for maintaining healthy growth. We found that sulfite ≤20 mmol/L had no obvious effect on the total lipid content and fatty acid profiles of the algae. Thus, the results suggest it is feasible to use flue gas for the mass production of feedstock for biodiesel using Chlorella sp. XQ-20044, without preliminary removal of SO2, assuming there is adequate control of the pH.

  6. Sulfite oxidation in Sinorhizobium meliloti.

    PubMed

    Wilson, Jeremy J; Kappler, Ulrike

    2009-12-01

    Sulfite-oxidizing enzymes (SOEs) are crucial for the metabolism of many cells and are particularly important in bacteria oxidizing inorganic or organic sulfur compounds. However, little is known about SOE diversity and metabolic roles. Sinorhizobium meliloti contains four candidate genes encoding SOEs of three different types, and in this work we have investigated the role of SOEs in S. meliloti and their possible link to the metabolism of the organosulfonate taurine. Low level SOE activity (approximately 1.4 U/mg) was present under all conditions tested while growth on taurine and thiosulfate induced high activities (5.5-8.8 U/mg) although S. meliloti cannot metabolize thiosulfate. Protein purification showed that although expression of two candidate genes matched SOE activity patterns, only a single group 2 SOE, SorT (SMc04049), is responsible for this activity. SorT is a heme-free, periplasmic homodimer (78 kDa) that has low homology to other bacterial SOEs. SorT has an apparent k(cat) of 343 s(-1) and high affinities for both sulfite (K(Mapp_pH8) 15.5 microM) and ferricyanide (K(Mapp_pH8) 3.44 microM), but not cytochrome c, suggesting a need for a high redox potential natural electron acceptor. K(Mapp_sulfite) was nearly invariant with pH which is in contrast to all other well characterized SOEs. SorT is part of an operon (SMc04049-04047) also containing a gene for a cytochrome c and an azurin, and these might be the natural electron acceptors for the enzyme. Phylogenetic analysis of SorT-related SOEs and enzymes of taurine degradation indicate that there is no link between the two processes.

  7. 21 CFR 182.3798 - Sodium sulfite.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium sulfite. 182.3798 Section 182.3798 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3798 Sodium sulfite. (a) Product. Sodium...

  8. Risk analysis of sulfites used as food additives in China.

    PubMed

    Zhang, Jian Bo; Zhang, Hong; Wang, Hua Li; Zhang, Ji Yue; Luo, Peng Jie; Zhu, Lei; Wang, Zhu Tian

    2014-02-01

    This study was to analyze the risk of sulfites in food consumed by the Chinese people and assess the health protection capability of maximum-permitted level (MPL) of sulfites in GB 2760-2011. Sulfites as food additives are overused or abused in many food categories. When the MPL in GB 2760-2011 was used as sulfites content in food, the intake of sulfites in most surveyed populations was lower than the acceptable daily intake (ADI). Excess intake of sulfites was found in all the surveyed groups when a high percentile of sulfites in food was in taken. Moreover, children aged 1-6 years are at a high risk to intake excess sulfites. The primary cause for the excess intake of sulfites in Chinese people is the overuse and abuse of sulfites by the food industry. The current MPL of sulfites in GB 2760-2011 protects the health of most populations.

  9. Sulfite Reductase Protects Plants against Sulfite Toxicity1[W][OA

    PubMed Central

    Yarmolinsky, Dmitry; Brychkova, Galina; Fluhr, Robert; Sagi, Moshe

    2013-01-01

    Plant sulfite reductase (SiR; Enzyme Commission 1.8.7.1) catalyzes the reduction of sulfite to sulfide in the reductive sulfate assimilation pathway. Comparison of SiR expression in tomato (Solanum lycopersicum ‘Rheinlands Ruhm’) and Arabidopsis (Arabidopsis thaliana) plants revealed that SiR is expressed in a different tissue-dependent manner that likely reflects dissimilarity in sulfur metabolism between the plant species. Using Arabidopsis and tomato SiR mutants with modified SiR expression, we show here that resistance to ectopically applied sulfur dioxide/sulfite is a function of SiR expression levels and that plants with reduced SiR expression exhibit higher sensitivity than the wild type, as manifested in pronounced leaf necrosis and chlorophyll bleaching. The sulfite-sensitive mutants accumulate applied sulfite and show a decline in glutathione levels. In contrast, mutants that overexpress SiR are more tolerant to sulfite toxicity, exhibiting little or no damage. Resistance to high sulfite application is manifested by fast sulfite disappearance and an increase in glutathione levels. The notion that SiR plays a role in the protection of plants against sulfite is supported by the rapid up-regulation of SiR transcript and activity within 30 min of sulfite injection into Arabidopsis and tomato leaves. Peroxisomal sulfite oxidase transcripts and activity levels are likewise promoted by sulfite application as compared with water injection controls. These results indicate that, in addition to participating in the sulfate assimilation reductive pathway, SiR also plays a role in protecting leaves against the toxicity of sulfite accumulation. PMID:23221833

  10. Overexpression of a maize sulfite oxidase gene in tobacco enhances tolerance to sulfite stress via sulfite oxidation and CAT-mediated H2O2 scavenging.

    PubMed

    Xia, Zongliang; Sun, Kaile; Wang, Meiping; Wu, Ke; Zhang, Hua; Wu, Jianyu

    2012-01-01

    Sulfite oxidase (SO) plays an important role in sulfite metabolism. To date, the molecular mechanisms of sulfite metabolism in plants are largely unknown. Previously, a full-length cDNA of the putative sulfite oxidase gene from maize (ZmSO) was cloned, and its response to SO(2)/sulfite stress at the transcriptional level was characterized. In this study, the recombinant ZmSO protein was purified from E. coli. It exhibited sulfite-dependent activity and had strong affinity for the substrate sulfite. Over-expression (OE) of ZmSO in tobacco plants enhanced their tolerance to sulfite stress. The plants showed much less damage, less sulfite accumulation, but greater amounts of sulfate. This suggests that tolerance of transgenic plants to sulfite was enhanced by increasing SO expression levels. Interestingly, H(2)O(2) accumulation levels by histochemical detection and quantitative determination in the OE plants were much less than those in the wild-type upon sulfite stress. Furthermore, reductions of catalase levels detected in the OE lines were considerably less than in the wild-type plants. This indicates that SO may play an important role in protecting CAT from inhibition by excess sulfite. Collectively, these data demonstrate that transgenic tobacco plants over-expressing ZmSO enhance tolerance to excess sulfite through sulfite oxidation and catalase-mediated hydrogen peroxide scavenging. This is the first SO gene from monocots to be functionally characterized. PMID:22693572

  11. Measurement of oxidation rate of sulfite in rain water in Yokohama, Japan

    SciTech Connect

    Tanaka, S.; Yamanaka, K.; Hashimoto, Y.

    1986-04-01

    In recent years, the influences of acid rain such as the acidification of lake water, on bio-system by the heavy metals from effluent of soils with acid rain and also on the structural materials of buildings are seriously discussed. Sulfur and nitrogen that are contained in fossil fuels are released into the atmosphere by the fuel combustion as their oxides dissolve in rain drops as sulfite and nitrous ions, where they are further oxidized into sulfate and nitrate ions These ions lower the pH of rain water resulting so-called acid rain. Therefore, it is important to accurately determine these ions in rain water for the investigation of reality of acid rain. However, it is not easy to accurately determine these ions, especially for sulfite ions in rain water, since they are quickly oxidized by the catalytic action of metallic ions such as ferric and manganous ions. And light, temperature, pH of solution and also species and concentrations of dissolved metallic ions as catalysts, must be influential factors for the rate of oxidation of sulfite ions. In this paper, first, the rate of oxidation of sulfite ion in the test solutions by the catalytic reactions of metallic ions was examined, since the metallic ions is most influential in the oxidation of sulfite ion, and then the relations between the rate of oxidation of sulfite ion and the metallic ions were investigated for rain samples. The contribution of hydrogen ion that was produced by the oxidation of sulfite ion to sulfate was also examined for the change of pH values of rain water.

  12. Elucidating the Catalytic Mechanism of Sulfite Oxidizing Enzymes using Structural, Spectroscopic and Kinetic Analyses

    PubMed Central

    Johnson-Winters, Kayunta; Tollin, Gordon; Enemark, John H.

    2010-01-01

    Sulfite oxidizing enzymes (SOEs) are molybdenum cofactor dependent enzymes that are found in plants, animals and bacteria. Sulfite oxidase (SO) is found in animals and plants, while sulfite dehydrogenase (SDH) is found in bacteria. In animals, SO catalyzes the oxidation of toxic sulfite to sulfate as the final step in the catabolism of the sulfur-containing amino acids, methionine and cysteine. In humans, sulfite oxidase deficiency is an inherited recessive disorder that produces severe neonatal neurological problems that lead to early death. Plant SO (PSO) also plays an important role in sulfite detoxification, but in addition serves as an intermediate enzyme in the assimilatory reduction of sulfate. In vertebrates the proposed catalytic mechanism of SO involves two intramolecular one-electron transfer (IET) steps from the molybdenum cofactor to the iron of the integral b-type heme. A similar mechanism is proposed for SDH, involving its molybdenum cofactor and c-type heme. However, PSO, which lacks an integral heme cofactor, uses molecular oxygen as its electron acceptor. Here we review recent results for SOEs from kinetic measurements, computational studies, electron paramagnetic resonance (EPR) spectroscopy, electrochemical measurements, and site-directed mutagenesis on active site residues of SOEs and of the flexible polypepetide tether that connects the heme and molybdenum domains of human SO. Rapid-kinetic studies of PSO are also discussed. PMID:20666399

  13. Bacterial sulfite dehydrogenases in organotrophic metabolism: separation and identification in Cupriavidus necator H16 and in Delftia acidovorans SPH-1.

    PubMed

    Denger, Karin; Weinitschke, Sonja; Smits, Theo H M; Schleheck, David; Cook, Alasdair M

    2008-01-01

    The utilization of organosulfonates as carbon sources by aerobic or nitrate-reducing bacteria usually involves a measurable, uncharacterized sulfite dehydrogenase. This is tacitly assumed to be sulfite : ferricytochrome-c oxidoreductase [EC 1.8.2.1], despite negligible interaction with (eukaryotic) cytochrome c: the enzyme is assayed at high specific activity with ferricyanide as electron acceptor. Purified periplasmic sulfite dehydrogenases (SorAB, SoxCD) are known from chemoautotrophic growth and are termed 'sulfite oxidases' by bioinformatic services. The catalytic unit (SorA, SoxC; termed 'sulfite oxidases' cd02114 and cd02113, respectively) binds a molybdenum-cofactor (Moco), and involves a cytochrome c (SorB, SoxD) as electron acceptor. The genomes of several bacteria that express a sulfite dehydrogenase during heterotrophic growth contain neither sorAB nor soxCD genes; others contain at least four paralogues, for example Cupriavidus necator H16, which is known to express an inducible sulfite dehydrogenase during growth with taurine (2-aminoethanesulfonate). This soluble enzyme was enriched 320-fold in four steps. The 40 kDa protein (denatured) had an N-terminal amino acid sequence which started at position 42 of the deduced sequence of H16_B0860 (termed 'sulfite oxidase' cd02114), which we named SorA. The neighbouring gene is an orthologue of sorB, and the sorAB genes were co-transcribed. Cell fractionation showed SorA to be periplasmic. The corresponding enzyme in Delftia acidovorans SPH-1 was enriched 270-fold, identified as Daci_0055 (termed 'sulfite oxidase' cd02110) and has a cytochrome c encoded downstream. We presume, from genomic data for bacteria and archaea, that there are several subgroups of sulfite dehydrogenases, which all contain a Moco, and transfer electrons to a specific cytochrome c.

  14. Vanillin: Synthetic Flavoring from Spent Sulfite Liquor

    NASA Astrophysics Data System (ADS)

    Hocking, Martin B.

    1997-09-01

    Separation of the lignin component of wood from the cellulose presents an opportunity to access various interesting products from the lignin fragments. The lignin represents availability of a sizable renewable resource. Vanillin, or 3-methoxy-4-hydroxybenzaldehyde, is one of a series of related substituted aromatic flavor constituents, and represents one of the potentially profitable possibilities. Vanillin production from the lignin-containing waste liquor obtained from acid sulfite pulping of wood began in North America in the mid 1930's. By 1981 one plant at Thorold, Ontario produced 60% of the contemporary world supply of vanillin. The process also simultaneously decreased the organic loading of the aqueous waste streams of the pulping process. Today, however, whilst vanillin production from lignin is still practiced in Norway and a few other areas, all North American facilities using this process have closed, primarily for environmental reasons. New North American vanillin plants use petrochemical raw materials. An innovation is needed to help overcome the environmental problems of this process before vanillin production from lignin is likely to resume here. Current interest in the promotion of chemicals production from renewable raw materials reinforces the incentive to do this.

  15. A sensitive and selective on-line amperometric sulfite biosensor using sulfite oxidase immobilized on a magnetite-gold-folate nanocomposite modified carbon-paste electrode.

    PubMed

    Sroysee, Wongduan; Ponlakhet, Kitayanan; Chairam, Sanoe; Jarujamrus, Purim; Amatatongchai, Maliwan

    2016-08-15

    We describe a novel amperometric sulfite biosensor, comprising a carbon-paste electrode (Fe3O4@Au-Cys-FA/CPE) modified with immobilized sulfite oxidase (SOx) on a gold-coated magnetite nanoparticle core, encased within a conjugated folic acid (FA) cysteine (Cys) shell. The biosensor electrode was fabricated using a polydimethylsiloxane (PDMS) and mineral oil mixture as binder, which also enhances the physical stability and sensitivity of the electrode. The developed biosensor displays good electrocatalytic activity toward oxidation of H2O2, which occurs by an enzymatic reaction between SOx and sulfite. The Fe3O4@Au-Cys-FA electrode exhibits good electrocatalytic activity, and has good retention of chemisorbed SOx on the electrode because of its large surface area. Sulfite was quantified using amperometric measurements from the Fe3O4@Au-Cys-FA/CPE biosensor, and using an in-house assembled flow cell at +0.35V (vs. Ag/AgCl), with a phosphate buffer carrier (0.10M, pH 7.0) at a flow rate of 0.8mLmin(-1). The system detects sulfite over the range 0.1-200mgL(-1) (r(2)=0.998), with a detection limit of 10µgL(-1) (3σ of blank). The system exhibits acceptable precision (%R.S.D.=3.1%), rapid sample throughput (109samplesh(-1)), and good stability (2w). The developed biosensor shows satisfactory tolerance to potential interferences, such as sugars, anions, ascorbic acid, and ethanol. We applied the developed method to the determination of sulfite content in wines and pickled food extracts, and our results are in good agreement with those obtained by the standard iodometric method.

  16. Diversity of Dissimilatory Sulfite Reductase Genes (dsrAB) in a Salt Marsh Impacted by Long-Term Acid Mine Drainage▿ †

    PubMed Central

    Moreau, John W.; Zierenberg, Robert A.; Banfield, Jillian F.

    2010-01-01

    Sulfate-reducing bacteria (SRB) play a major role in the coupled biogeochemical cycling of sulfur and chalcophilic metal(loid)s. By implication, they can exert a strong influence on the speciation and mobility of multiple metal(loid) contaminants. In this study, we combined DsrAB gene sequencing and sulfur isotopic profiling to identify the phylogeny and distribution of SRB and to assess their metabolic activity in salt marsh sediments exposed to acid mine drainage (AMD) for over 100 years. Recovered dsrAB sequences from three sites sampled along an AMD flow path indicated the dominance of a single Desulfovibrio species. Other major sequence clades were related most closely to Desulfosarcina, Desulfococcus, Desulfobulbus, and Desulfosporosinus species. The presence of metal sulfides with low δ34S values relative to δ34S values of pore water sulfate showed that sediment SRB populations were actively reducing sulfate under ambient conditions (pH of ∼2), although possibly within less acidic microenvironments. Interestingly, δ34S values for pore water sulfate were lower than those for sulfate delivered during tidal inundation of marsh sediments. 16S rRNA gene sequence data from sediments and sulfur isotope data confirmed that sulfur-oxidizing bacteria drove the reoxidation of biogenic sulfide coupled to oxygen or nitrate reduction over a timescale of hours. Collectively, these findings imply a highly dynamic microbially mediated cycling of sulfate and sulfide, and thus the speciation and mobility of chalcophilic contaminant metal(loid)s, in AMD-impacted marsh sediments. PMID:20472728

  17. Sulfite Oxidase Activity Is Essential for Normal Sulfur, Nitrogen and Carbon Metabolism in Tomato Leaves

    PubMed Central

    Brychkova, Galina; Yarmolinsky, Dmitry; Batushansky, Albert; Grishkevich, Vladislav; Khozin-Goldberg, Inna; Fait, Aaron; Amir, Rachel; Fluhr, Robert; Sagi, Moshe

    2015-01-01

    Plant sulfite oxidase [SO; E.C.1.8.3.1] has been shown to be a key player in protecting plants against exogenous toxic sulfite. Recently we showed that SO activity is essential to cope with rising dark-induced endogenous sulfite levels in tomato plants (Lycopersicon esculentum/Solanum lycopersicum Mill. cv. Rheinlands Ruhm). Here we uncover the ramifications of SO impairment on carbon, nitrogen and sulfur (S) metabolites. Current analysis of the wild-type and SO-impaired plants revealed that under controlled conditions, the imbalanced sulfite level resulting from SO impairment conferred a metabolic shift towards elevated reduced S-compounds, namely sulfide, S-amino acids (S-AA), Co-A and acetyl-CoA, followed by non-S-AA, nitrogen and carbon metabolite enhancement, including polar lipids. Exposing plants to dark-induced carbon starvation resulted in a higher degradation of S-compounds, total AA, carbohydrates, polar lipids and total RNA in the mutant plants. Significantly, a failure to balance the carbon backbones was evident in the mutants, indicated by an increase in tricarboxylic acid cycle (TCA) cycle intermediates, whereas a decrease was shown in stressed wild-type plants. These results indicate that the role of SO is not limited to a rescue reaction under elevated sulfite, but SO is a key player in maintaining optimal carbon, nitrogen and sulfur metabolism in tomato plants. PMID:27135342

  18. A Sulfite Respiration Pathway from Thermus thermophilus and the Key Role of Newly Identified Cytochrome c550 ▿

    PubMed Central

    Robin, Sylvain; Arese, Marzia; Forte, Elena; Sarti, Paolo; Giuffrè, Alessandro; Soulimane, Tewfik

    2011-01-01

    Sulfite, produced for instance during amino acid metabolism, is a very reactive and toxic compound. Various detoxification mechanisms exist, but sulfite oxidoreductases (SORs) are one of the major actors in sulfite remediation in bacteria and animals. Here we describe the existence of an operon in the extreme thermophilic bacterium Thermus thermophilus HB8 encoding both a SOR and a diheme c-type cytochrome. The in vitro analysis clearly showed that the newly identified cytochrome c550 acts as an acceptor of the electrons generated by the SOR enzyme during the oxidation of sulfite. The electrons are then rapidly shuttled via cytochrome c552 to the terminal ba3- and caa3-type oxidases, thereby unveiling a novel electron transfer pathway, linking sulfite oxidation to oxygen reduction in T. thermophilus: sulfite → SORHB8 → cytochrome c550 → cytochrome c552 → ba3 oxidase/caa3 oxidase → O2. The description of the complete pathway reveals that electrons generated during sulfite oxidation by the SOR are funneled into the respiratory chain, participating in the energy production of T. thermophilus. PMID:21665981

  19. Production development and utilization of Zimmer Station wet FGD by-products. Final report. Volume 4, A laboratory study conducted in fulfillment of Phase 2, Objective 1 titled. Inhibition of acid production in coal refuse amended with calcium sulfite and calcium sulfate - containing FGD solids

    SciTech Connect

    Hao, Y. L.; Dick, W. A.; Stehouwer, R. C.; Bigham, J. M.

    1998-06-30

    Control of S02 emission from coal combustion requires desulfurization of coal before its combustion to produce coal refuse. Alternatively, gaseous emissions from coal combustion may be scrubbed to yield flue gas desulfurization (FGD) by-products that include calcium sulfite (CaSO3∙0.5H2O or simply CaS03). Acid production in coal refuse due to pyrite oxidation and disposal of large amounts of FGD can cause environmental degradation. Addition of CaS03 and CaS03-containing FGD to coal refuse may reduce the amounts of oxygen and ferric ion available to oxidize pyrite because the sulfite moiety in CaS03 is a strong reductant and thus may mitigate acid production in coal refuse. In Chapter 1, it was shown that CaS03 efficiently scavenged dissolved oxygen and ferric ion in water under the conditions commonly encountered in a coal refuse disposal environment. In the presence ofCaS03, the concentration of dissolved oxygen in water exposed to the atmosphere declined to below 0.01 mg L"1 at pH <8.0. In Chapter 2, it was demonstrated that CaS03 prevented a pH drop in coal refuse slurry when 0.2 gCaS03 was added to a 2% fresh coal refuse slurry every three days. Calcium sulfite also inhibited acid leaching from fresh coal refuse in bench-scale columns under controlled conditions. During the initial 13 weeks of leaching, the total amounts of titratable acidity, soluble H\\ Fe, and Al from CaS03-treated refuse (6.4 gin 50 g fresh coal refuse) were only 26%,10%, 32%, and 39% of those of the control columns, respectively. A combination of CaS03 with CaC03 or fly ash enhanced the inhibitory effect of CaS03 on acid leaching. Calcium sulfite-containing FGD which combined CaS03, CaC03, fly ash, and gypsum showed a much stronger inhibitory effect on acid leaching than CaS03 alone. This

  20. Generation of PHB from Spent Sulfite Liquor Using Halophilic Microorganisms

    PubMed Central

    Weissgram, Michaela; Gstöttner, Janina; Lorantfy, Bettina; Tenhaken, Raimund; Herwig, Christoph; Weber, Hedda K.

    2015-01-01

    Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB.

  1. Generation of PHB from Spent Sulfite Liquor Using Halophilic Microorganisms

    PubMed Central

    Weissgram, Michaela; Gstöttner, Janina; Lorantfy, Bettina; Tenhaken, Raimund; Herwig, Christoph; Weber, Hedda K.

    2015-01-01

    Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB. PMID:27682089

  2. 21 CFR 182.3798 - Sodium sulfite.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium sulfite. 182.3798 Section 182.3798 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3798...

  3. 21 CFR 582.3798 - Sodium sulfite.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium sulfite. 582.3798 Section 582.3798 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  4. Oxidation of ammonium sulfite in aqueous solutions using ozone technology

    NASA Astrophysics Data System (ADS)

    Li, Yue; Shang, Kefeng; Lu, Na; Li, Jie; Wu, Yan

    2013-03-01

    How to deal with unstable ammonium sulfite, the byproduct of flue gas desulfuration by ammonia absorption methods, has been a difficult problem in recent years. Oxidation of ammonium sulfite in aqueous solutions using ozone produced by a surface discharge system was investigated in the paper. The oxidation efficiency of ammonium sulfite by ozone and traditional air aeration were compared, and the factors including ozone concentration, gas flow rate, initial concentration of ammonium sulfite solution and reaction temperature were discussed. The results show that the oxidation efficiency of ammonium sulfite by ozone technology reached nearly 100% under the optimum conditions, which had a significant increase compared with that by air aeration.

  5. Structure-Based Alteration of Substrate Specificity and Catalytic Activity of Sulfite Oxidase from Sulfite Oxidation to Nitrate Reduction

    SciTech Connect

    Qiu, James A.; Wilson, Heather L.; Rajagopalan, K.V.

    2012-04-18

    Eukaryotic sulfite oxidase is a dimeric protein that contains the molybdenum cofactor and catalyzes the metabolically essential conversion of sulfite to sulfate as the terminal step in the metabolism of cysteine and methionine. Nitrate reductase is an evolutionarily related molybdoprotein in lower organisms that is essential for growth on nitrate. In this study, we describe human and chicken sulfite oxidase variants in which the active site has been modified to alter substrate specificity and activity from sulfite oxidation to nitrate reduction. On the basis of sequence alignments and the known crystal structure of chicken sulfite oxidase, two residues are conserved in nitrate reductases that align with residues in the active site of sulfite oxidase. On the basis of the crystal structure of yeast nitrate reductase, both positions were mutated in human sulfite oxidase and chicken sulfite oxidase. The resulting double-mutant variants demonstrated a marked decrease in sulfite oxidase activity but gained nitrate reductase activity. An additional methionine residue in the active site was proposed to be important in nitrate catalysis, and therefore, the triple variant was also produced. The nitrate reducing ability of the human sulfite oxidase triple mutant was nearly 3-fold greater than that of the double mutant. To obtain detailed structural data for the active site of these variants, we introduced the analogous mutations into chicken sulfite oxidase to perform crystallographic analysis. The crystal structures of the Mo domains of the double and triple mutants were determined to 2.4 and 2.1 {angstrom} resolution, respectively.

  6. Human sulfite oxidase electrochemistry on gold nanoparticles modified electrode.

    PubMed

    Frasca, Stefano; Rojas, Oscar; Salewski, Johannes; Neumann, Bettina; Stiba, Konstanze; Weidinger, Inez M; Tiersch, Brigitte; Leimkühler, Silke; Koetz, Joachim; Wollenberger, Ulla

    2012-10-01

    The present study reports a facile approach for sulfite biosensing, based on enhanced direct electron transfer of a human sulfite oxidase (hSO) immobilized on a gold nanoparticles modified electrode. The spherical core shell AuNPs were prepared via a new method by reduction of HAuCl(4) with branched poly(ethyleneimine) in an ionic liquids resulting particles with a diameter less than 10nm. These nanoparticles were covalently attached to a mercaptoundecanoic acid modified Au-electrode where then hSO was adsorbed and an enhanced interfacial electron transfer and electrocatalysis was achieved. UV/Vis and resonance Raman spectroscopy, in combination with direct protein voltammetry, are employed for the characterization of the system and reveal no perturbation of the structural integrity of the redox protein. The proposed biosensor exhibited a quick steady-state current response, within 2 s, a linear detection range between 0.5 and 5.4 μM with a high sensitivity (1.85 nA μM(-1)). The investigated system provides remarkable advantages in the possibility to work at low applied potential and at very high ionic strength. Therefore these properties could make the proposed system useful in the development of bioelectronic devices and its application in real samples.

  7. Highly sensitive and stable electrochemical sulfite biosensor incorporating a bacterial sulfite dehydrogenase.

    PubMed

    Kalimuthu, Palraj; Tkac, Jan; Kappler, Ulrike; Davis, Jason J; Bernhardt, Paul V

    2010-09-01

    This paper describes a highly sensitive electrochemical (voltammetric) determination of sulfite using a combination of Starkeya novella sulfite dehydrogenase (SDH), horse heart cytochrome c (cyt c), and a self-assembled monolayer of 11-mercaptoundecanol (MU) cast on a gold electrode. The biosensor was optimized in terms of pH and the ratio of cyt c/SDH. The electrocatalytic oxidation current of sulfite increased linearly from 1 to 6 microM at the enzyme-modified electrode with a correlation coefficient of 0.9995 and an apparent Michaelis constant (K(M,app)) of 43 microM. Using an amperometric method, the low detection limit for sulfite at the enzyme-modified electrode was 44 pM (signal-to-noise ratio = 3). The modified electrode retained a stable response for 3 days while losing only ca. 4% of its initial sensitivity during a 2 week storage period in 50 mM Tris buffer solution at 4 degrees C. The enzyme electrode was successfully used for the determination of sulfite in beer and white wine samples. The results of these electrochemical analyses agreed well with an independent spectrophotometric method using Ellman's reagent, but the detection limit was far superior using the electrochemical method. PMID:20698497

  8. Dewatering of flue gas desulfurization sulfite solids

    SciTech Connect

    Garrison, F.C.; Wells, W.L.

    1984-06-12

    The dewatering capabilities of sulfite sludges from flue gas desulfurization facilities are substantially improved by the addition of relatively small amounts of sodium thiosulfate additive, or additives derived from or related to sodium thiosulfate, into the scrubber slurry liquor. As an added embellishment, these predetermined amounts of said additives are greater than those required for effecting substantial scale inhibition in the scrubber innards. Subsequently, conventional dewatering of the sulfite sludge to about 80 to 90 percent solids directly produces a waste product disposable in both an economically and an environmentally acceptable manner, in that the thixotropic characteristics of such sludges which are associated therewith upwards to about 70 percent solids therein are completely eliminated.

  9. Thermodynamic fundamentals of ferrous cake sulfitization

    NASA Astrophysics Data System (ADS)

    Tyurin, A. G.; Vasekha, M. V.; Biryukov, A. I.

    2016-03-01

    The Pourbaix diagrams of the systems SO 4 2- -SO 3 2- -H2O and iron hydroxide (oxide)-H2O are refined. The E(pH) dependence of the sulfitization of iron(III) hydroxide is refined with allowance for the regions of predominant phase constituents of the systems. The potential E-pH electrochemical equilibrium diagrams of the systems Fe(OH)3-H2SO4-SO 3 2- -H2O, FeOOH-H2SO4-SO 3 2- -H2O, and Fe2O3-H2SO4-SO 3 2- -H2O are plotted. These diagrams can be considered as a thermodynamic basis for the sulfite conversion of the ferrous cake of copper-nickel production.

  10. Differential sensitivity of duckweeds (Lemnaceae) to sulfite: I. Carbon assimilation and frond replication rate as factors influencing sulfite phytotoxicity

    SciTech Connect

    Takemoto, B.K.; Noble, R.D.

    1986-01-01

    The thiol content and hydrogen sulfide emission responses of duckweeds (Lemnaceae) differentially sensitive to sulfite enrichment were studied, at two levels of irradiance. The objectives were to examine the relationship of selected parameters of sulfite metabolism to sulfite sensitivity, and the role of light level on modifying sulfite metabolic responses and duckweed sulfite sensitivity. Under low light, thiol contents were increased 30 to 40% by sulfite in all three duckweeds examined. Hydrogen sulfide was emitted by all three species, and emission rates were up to four times higher in the sulfite tolerant duckweed Lemna valdiviana. Under high light, sulfite increased thiol contents by an average of 40% in L. valdiviana and Spirodela oligorhiza, but only 20% in Lemna gibba. The greater light enhancement of thiol content exhibited by L. valdiviana and S. oligorhiza may be indicative of larger or more numerous sulfur sinks. Hydrogen sulfide emission rates were also enhanced under high light, and L. gibba exhibited a 17% increase relative to its low light rate. In comparison, L. valdiviana and S. oligorhiza exhibited 55% and 60% increases, respectively. The ability to form elevated internal thiols and hydrogen sulfide were found to be important to sulfite tolerance in duckweeds. Enhancement of both processes under high light may contribute to increased tolerance of sulfite in L. gibba and S. oligorhiza. It is hypothesized that thiol production and hydrogen sulfide emission are important sulfite detoxification processes in duckweeds, and enhancement of sulfite detoxification is fundamental to the modification of duckweed sulfite sensitivity by the photoenvironment. 25 refs., 3 tabs.

  11. Investigation of the radiation stimulated oxidation of sulfite by molecular oxygen in aqueous solutions

    SciTech Connect

    Muratbekov, M.B.; Koroleva, G.Y.

    1986-09-01

    The principles of the radiation-stimulated oxidation of sulfite by molecular oxygen in the range of pH 11.0-14.6 were investigated. It was established that with increasing sulfite concentration, the kinetic order of the reaction with respect to sulfite falls from 1 to 0, and with respect to oxygen it increases from 0 to 1. This is explained by the fact that at low sulfite concentrations the rate-determining step of the process is the reaction SO/sub 5//sup -/ (HSO/sub 5/) + SO/sub 3//sup 2 -/ ..-->.. SO/sub 4//sup -/ (HSO/sub 4/) + SO/sub 4//sup 2 -/, while at high concentrations it is the reaction SO/sub 3/ + O/sub 2/ ..-->.. SO/sub 5//sup -/. The influence of the pH is explained on the assumption of the existence of two forms of the peroxomonosulfate radical, the more reactive of which is the acid. A number of ratios of reaction rate constants were determined.

  12. Composition of sulfited potatoes: comparison with fresh and frozen potatoes.

    PubMed

    Chalom, S; Elrezzi, E; Peña, P; Astiarsarán, I; Bello, J

    1995-02-01

    The content in moisture, fat, protein, carbohydrate, fibre and vitamin C was analyzed in three commercial types of potatoes: sulfited (treated with E223), frozen potatoes (pre-fried) and fresh potatoes (not processed). The composition of sulfited potatoes does not usually appear in food composition tables. Our results showed significant differences in the content of carbohydrates and fibre between sulfited and fresh potatoes. The content of vitamin C in sulfited potatoes, which is similar to that of frozen potatoes, was shown to be approximately half of that found in fresh potatoes. PMID:7792261

  13. Molecular Basis for Enzymatic Sulfite Oxidation -- HOW THREE CONSERVED ACTIVE SITE RESIDUES SHAPE ENZYME ACTIVITY

    SciTech Connect

    Bailey, Susan; Rapson, Trevor; Johnson-Winters, Kayunta; Astashkin, Andrei; Enemark, John; Kappler, Ulrike

    2008-11-10

    Sulfite dehydrogenases (SDHs) catalyze the oxidation and detoxification of sulfite to sulfate, a reaction critical to all forms of life. Sulfite-oxidizing enzymes contain three conserved active site amino acids (Arg-55, His-57, and Tyr-236) that are crucial for catalytic competency. Here we have studied the kinetic and structural effects of two novel and one previously reported substitution (R55M, H57A, Y236F) in these residues on SDH catalysis. Both Arg-55 and His-57 were found to have key roles in substrate binding. An R55M substitution increased Km(sulfite)(app) by 2-3 orders of magnitude, whereas His-57 was required for maintaining a high substrate affinity at low pH when the imidazole ring is fully protonated. This effect may be mediated by interactions of His-57 with Arg-55 that stabilize the position of the Arg-55 side chain or, alternatively, may reflect changes in the protonation state of sulfite. Unlike what is seen for SDHWT and SDHY236F, the catalytic turnover rates of SDHR55M and SDHH57A are relatively insensitive to pH (~;;60 and 200 s-1, respectively). On the structural level, striking kinetic effects appeared to correlate with disorder (in SDHH57A and SDHY236F) or absence of Arg-55 (SDHR55M), suggesting that Arg-55 and the hydrogen bonding interactions it engages in are crucial for substrate binding and catalysis. The structure of SDHR55M has sulfate bound at the active site, a fact that coincides with a significant increase in the inhibitory effect of sulfate in SDHR55M. Thus, Arg-55 also appears to be involved in enabling discrimination between the substrate and product in SDH.

  14. Oxygen reactivity of mammalian sulfite oxidase provides a concept for the treatment of sulfite oxidase deficiency.

    PubMed

    Belaidi, Abdel A; Röper, Juliane; Arjune, Sita; Krizowski, Sabina; Trifunovic, Aleksandra; Schwarz, Guenter

    2015-07-15

    Mammalian sulfite oxidase (SO) is a dimeric enzyme consisting of a molybdenum cofactor- (Moco) and haem-containing domain and catalyses the oxidation of toxic sulfite to sulfate. Following sulfite oxidation, electrons are passed from Moco via the haem cofactor to cytochrome c, the terminal electron acceptor. In contrast, plant SO (PSO) lacks the haem domain and electrons shuttle from Moco to molecular oxygen. Given the high similarity between plant and mammalian SO Moco domains, factors that determine the reactivity of PSO towards oxygen, remained unknown. In the present study, we generated mammalian haem-deficient and truncated SO variants and demonstrated their oxygen reactivity by hydrogen peroxide formation and oxygen-consumption studies. We found that intramolecular electron transfer between Moco and haem showed an inverse correlation to SO oxygen reactivity. Haem-deficient SO variants exhibited oxygen-dependent sulfite oxidation similar to PSO, which was confirmed further using haem-deficient human SO in a cell-based assay. This finding suggests the possibility to use oxygen-reactive SO variants in sulfite detoxification, as the loss of SO activity is causing severe neurodegeneration. Therefore we evaluated the potential use of PEG attachment (PEGylation) as a modification method for future enzyme substitution therapies using oxygen-reactive SO variants, which might use blood-dissolved oxygen as the electron acceptor. PEGylation has been shown to increase the half-life of other therapeutic proteins. PEGylation resulted in the modification of up to eight surface-exposed lysine residues of SO, an increased conformational stability and similar kinetic properties compared with wild-type SO. PMID:26171830

  15. Oxygen reactivity of mammalian sulfite oxidase provides a concept for the treatment of sulfite oxidase deficiency.

    PubMed

    Belaidi, Abdel A; Röper, Juliane; Arjune, Sita; Krizowski, Sabina; Trifunovic, Aleksandra; Schwarz, Guenter

    2015-07-15

    Mammalian sulfite oxidase (SO) is a dimeric enzyme consisting of a molybdenum cofactor- (Moco) and haem-containing domain and catalyses the oxidation of toxic sulfite to sulfate. Following sulfite oxidation, electrons are passed from Moco via the haem cofactor to cytochrome c, the terminal electron acceptor. In contrast, plant SO (PSO) lacks the haem domain and electrons shuttle from Moco to molecular oxygen. Given the high similarity between plant and mammalian SO Moco domains, factors that determine the reactivity of PSO towards oxygen, remained unknown. In the present study, we generated mammalian haem-deficient and truncated SO variants and demonstrated their oxygen reactivity by hydrogen peroxide formation and oxygen-consumption studies. We found that intramolecular electron transfer between Moco and haem showed an inverse correlation to SO oxygen reactivity. Haem-deficient SO variants exhibited oxygen-dependent sulfite oxidation similar to PSO, which was confirmed further using haem-deficient human SO in a cell-based assay. This finding suggests the possibility to use oxygen-reactive SO variants in sulfite detoxification, as the loss of SO activity is causing severe neurodegeneration. Therefore we evaluated the potential use of PEG attachment (PEGylation) as a modification method for future enzyme substitution therapies using oxygen-reactive SO variants, which might use blood-dissolved oxygen as the electron acceptor. PEGylation has been shown to increase the half-life of other therapeutic proteins. PEGylation resulted in the modification of up to eight surface-exposed lysine residues of SO, an increased conformational stability and similar kinetic properties compared with wild-type SO.

  16. Synthesis and antiviral evaluation of bisnoradamantane sulfites and related compounds.

    PubMed

    Valverde, Elena; Torres, Eva; Guardiola, Salvador; Naesens, Lieve; Vázquez, Santiago

    2011-03-01

    The reaction of a series of 1,2-diols with thionyl chloride led to bisnoradamantane sulfites in very good yields. The reaction has also been applied to related polycyclic scaffolds. The compounds have been tested for antiviral activity but none of them showed to be active. Several attempts to generate and trap SO from these polycyclic sulfites have been unsuccessful.

  17. The oxygen isotope equilibrium fractionation between sulfite species and water

    NASA Astrophysics Data System (ADS)

    Müller, Inigo A.; Brunner, Benjamin; Breuer, Christian; Coleman, Max; Bach, Wolfgang

    2013-11-01

    Sulfite is an important sulfoxy intermediate in oxidative and reductive sulfur cycling in the marine and terrestrial environment. Different aqueous sulfite species exist, such as dissolved sulfur dioxide (SO2), bisulfite (HSO3-), pyrosulfite (S2O52-) and sulfite sensu stricto (SO32-), whereas their relative abundance in solution depends on the concentration and the pH. Conversion of one species into another is rapid and involves in many cases incorporation of oxygen from, or release of oxygen to, water (e.g. SO2 + H2O ↔ HSO3- + H+), resulting in rapid oxygen isotope exchange between sulfite species and water. Consequently, the oxygen isotope composition of sulfite is strongly influenced by the oxygen isotope composition of water. Since sulfate does not exchange oxygen isotopes with water under most earth surface conditions, it can preserve the sulfite oxygen isotope signature that it inherits via oxidative and reductive sulfur cycling. Therefore, interpretation of δO values strongly hinges on the oxygen isotope equilibrium fractionation between sulfite and water which is poorly constrained. This is in large part due to technical difficulties in extraction of sulfite from solution for oxygen isotope analysis.

  18. Sulfite-dependent mutagenicity of benzo[a]pyrene derivatives.

    PubMed

    Reed, G A

    1987-08-01

    Benzo[a]pyrene (BP) and sulfur dioxide (SO2) are ubiquitous air pollutants and are also components of tobacco smoke. Although SO2 itself is not carcinogenic, concurrent administration with BP results in enhancement of respiratory tract tumorigenesis. In biological systems, SO2 exists as its hydrated form, sulfite (SO3(2-) ). Sulfite readily undergoes autoxidation, generating potent oxidant species. When 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP-7,8-diol) is included in sulfite autoxidation mixtures it is converted to more polar products, most notably 7,8,9,10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]pyrenes (BP tetraols). This implies the intermediacy of 7,8-dihydroxy-9,10-epoxy- 7,8,9,10-tetrahydro-benzo[a]pyrenes (BPDE). We report here the sulfite-dependent conversion of BP-7,8-diol to forms highly mutagenic to Salmonella typhimurium strain TA 98. This activation is observed at BP-7,8-diol concentrations of from 2 to 40 microM and at sulfite concentrations of from 0.5 to 10 mM. In the presence of 10 microM BP-7,8-diol, half-maximal activation is observed at 1.6 mM sulfite. Sulfite itself is neither toxic nor mutagenic to the bacteria under these conditions. The time course of the activation of BP-7,8-diol and its sensitivity to inhibition by antioxidants indicate a requirement for sulfite autoxidation. These data further support the sulfite-dependent epoxidation of BP-7,8-diol. Not only does sulfite convert this promutagen to its active mutagenic form, sulfite also enhances the mutagenic activity of BP diolepoxides toward the tester strain. The reversion frequency in response to 0.1-0.5 microM anti-BPDE is increased by up to 33% in the presence of 1 mM sulfite, and by up to 270% with 10 mM sulfite. The mechanism of this enhancement of anti-BPDE activity is not known, but could be related to inhibition of the glutathione-S-transferase system which has been previously reported for sulfite. These results are discussed in regard to the noted cocarcinogenicity of

  19. Determination of total sulfite in wine by ion chromatography after in-sample oxidation.

    PubMed

    Koch, Matthias; Köppen, Robert; Siegel, David; Witt, Angelika; Nehls, Irene

    2010-09-01

    Sulfur dioxide (SO2) or sulfites are the most common preservatives used in winemaking. The level of total SO2 is subject to regulation. Currently, the regulatory determination of total SO2 (including sulfites) is done by the optimized Monier-Williams (OMW) method, which includes time-consuming distillation and titration steps. This paper describes the development and application of an alternative, rapid, straightforward, and reliable method for the determination of total sulfite in wine. In this method, a simple oxidation step using alkaline hydrogen peroxide (H2O2) solution is followed by ion chromatographic (IC) analysis of sulfate coupled with conductometric detection. Thirteen wines were analyzed in order to compare the in-sample oxidation method with the OMW-procedure. A t-test revealed satisfying compliance regarding sample preparation, i.e., alkaline H2O2 treatment and acidic distillation (OMW method). Comparable results were also obtained between IC analysis and acid/base titration. Our results indicate that the novel method (limit of quantification: 4 mg SO2 L(-1)) is well suited for the cost-efficient monitoring of regulatory limits. PMID:20690603

  20. Determination of total sulfite in wine by ion chromatography after in-sample oxidation.

    PubMed

    Koch, Matthias; Köppen, Robert; Siegel, David; Witt, Angelika; Nehls, Irene

    2010-09-01

    Sulfur dioxide (SO2) or sulfites are the most common preservatives used in winemaking. The level of total SO2 is subject to regulation. Currently, the regulatory determination of total SO2 (including sulfites) is done by the optimized Monier-Williams (OMW) method, which includes time-consuming distillation and titration steps. This paper describes the development and application of an alternative, rapid, straightforward, and reliable method for the determination of total sulfite in wine. In this method, a simple oxidation step using alkaline hydrogen peroxide (H2O2) solution is followed by ion chromatographic (IC) analysis of sulfate coupled with conductometric detection. Thirteen wines were analyzed in order to compare the in-sample oxidation method with the OMW-procedure. A t-test revealed satisfying compliance regarding sample preparation, i.e., alkaline H2O2 treatment and acidic distillation (OMW method). Comparable results were also obtained between IC analysis and acid/base titration. Our results indicate that the novel method (limit of quantification: 4 mg SO2 L(-1)) is well suited for the cost-efficient monitoring of regulatory limits.

  1. Sulfur Isotope Effects of Dissimilatory Sulfite Reductase.

    PubMed

    Leavitt, William D; Bradley, Alexander S; Santos, André A; Pereira, Inês A C; Johnston, David T

    2015-01-01

    The precise interpretation of environmental sulfur isotope records requires a quantitative understanding of the biochemical controls on sulfur isotope fractionation by the principle isotope-fractionating process within the S cycle, microbial sulfate reduction (MSR). Here we provide the only direct observation of the major ((34)S/(32)S) and minor ((33)S/(32)S, (36)S/(32)S) sulfur isotope fractionations imparted by a central enzyme in the energy metabolism of sulfate reducers, dissimilatory sulfite reductase (DsrAB). Results from in vitro sulfite reduction experiments allow us to calculate the in vitro DsrAB isotope effect in (34)S/(32)S (hereafter, [Formula: see text]) to be 15.3 ± 2‰, 2σ. The accompanying minor isotope effect in (33)S, described as [Formula: see text], is calculated to be 0.5150 ± 0.0012, 2σ. These observations facilitate a rigorous evaluation of the isotopic fractionation associated with the dissimilatory MSR pathway, as well as of the environmental variables that govern the overall magnitude of fractionation by natural communities of sulfate reducers. The isotope effect induced by DsrAB upon sulfite reduction is a factor of 0.3-0.6 times prior indirect estimates, which have ranged from 25 to 53‰ in (34)εDsrAB. The minor isotope fractionation observed from DsrAB is consistent with a kinetic or equilibrium effect. Our in vitro constraints on the magnitude of [Formula: see text] is similar to the median value of experimental observations compiled from all known published work, where (34)ε r-p = 16.1‰ (r-p indicates reactant vs. product, n = 648). This value closely matches those of MSR operating at high sulfate reduction rates in both laboratory chemostat experiments ([Formula: see text] 17.3 ± 1.5‰, 2σ) and in modern marine sediments ([Formula: see text] 17.3 ± 3.8‰). Targeting the direct isotopic consequences of a specific enzymatic processes is a fundamental step toward a biochemical foundation for reinterpreting the

  2. Sulfur Isotope Effects of Dissimilatory Sulfite Reductase

    PubMed Central

    Leavitt, William D.; Bradley, Alexander S.; Santos, André A.; Pereira, Inês A. C.; Johnston, David T.

    2015-01-01

    The precise interpretation of environmental sulfur isotope records requires a quantitative understanding of the biochemical controls on sulfur isotope fractionation by the principle isotope-fractionating process within the S cycle, microbial sulfate reduction (MSR). Here we provide the only direct observation of the major (34S/32S) and minor (33S/32S, 36S/32S) sulfur isotope fractionations imparted by a central enzyme in the energy metabolism of sulfate reducers, dissimilatory sulfite reductase (DsrAB). Results from in vitro sulfite reduction experiments allow us to calculate the in vitro DsrAB isotope effect in 34S/32S (hereafter, 34εDsrAB) to be 15.3 ± 2‰, 2σ. The accompanying minor isotope effect in 33S, described as 33λDsrAB, is calculated to be 0.5150 ± 0.0012, 2σ. These observations facilitate a rigorous evaluation of the isotopic fractionation associated with the dissimilatory MSR pathway, as well as of the environmental variables that govern the overall magnitude of fractionation by natural communities of sulfate reducers. The isotope effect induced by DsrAB upon sulfite reduction is a factor of 0.3–0.6 times prior indirect estimates, which have ranged from 25 to 53‰ in 34εDsrAB. The minor isotope fractionation observed from DsrAB is consistent with a kinetic or equilibrium effect. Our in vitro constraints on the magnitude of 34εDsrAB is similar to the median value of experimental observations compiled from all known published work, where 34εr−p = 16.1‰ (r–p indicates reactant vs. product, n = 648). This value closely matches those of MSR operating at high sulfate reduction rates in both laboratory chemostat experiments (34εSO4−H2S =  17.3 ± 1.5‰, 2σ) and in modern marine sediments (34εSO4−H2S =  17.3 ± 3.8‰). Targeting the direct isotopic consequences of a specific enzymatic processes is a fundamental step toward a biochemical foundation for reinterpreting the biogeochemical and geobiological sulfur isotope records in

  3. 21 CFR 201.22 - Prescription drugs containing sulfites; required warning statements.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Prescription drugs containing sulfites; required... Prescription drugs containing sulfites; required warning statements. (a) Sulfites are chemical substances that.... Examples of specific sulfites used to inhibit this oxidation process include sodium bisulfite,...

  4. Determination of added sulfites in dried garlic with a modified version of the optimized Monier-Williams method.

    PubMed

    Lafeuille, Jean-Louis; Lefevre, Stephane; Achouri, Djamila

    2007-01-01

    The optimized Monier-Williams method is slightly modified so that it could be applied for determining sulfite content in dried garlic. Dried garlic sample is directly acidified in a reactor at a pH below 3. At this pH level, the alliinase enzyme activity is irreversibly blocked, and the sulfur-containing amino acids such as alliin (the most abundant) present in dried garlic cannot be transformed into corresponding thiosulfinates such as allicin, which is absent in dried garlic. This prevents allicin from reacting with added sulfites and being probably converted to S-allyl thiosulfate, which is not volatile and has no taste. It is found that at a pH below 2.4 and at boiling water temperature, allicin produces sulfur dioxide in adequate quantity to explain the false-positive results when utilizing the optimized Monier-Williams method with allicin suppression for unsulfited dried garlic samples. Finally, when garlic samples are stabilized in a phosphoric acid buffer at a final pH around 2.4, no sulfite is produced during the Monier-Williams distillation, which is further proof there are no naturally occurring sulfites in unsulfited dried garlic under these mild conditions.

  5. The determination of sulfite levels and its oxidation in plant leaves.

    PubMed

    Brychkova, Galina; Yarmolinsky, Dmitry; Fluhr, Robert; Sagi, Moshe

    2012-07-01

    Sulfur is the sixth most abundant element in life and an important building block of proteins and cellular metabolites. Plants like bacteria can synthesize their sulfur-containing biomolecules from sulfate, where sulfite is an intermediate of the sulfur assimilation pathway. Above a certain threshold SO(2)/sulfite is cytotoxic and is rapidly metabolized to avoid damage. However, the existing data show considerable differences in basal sulfite levels both between species and apparent discrepancies in measured levels in the same species. In order to resolve this question we employed a sulfite detection method using chicken sulfite oxidase and developed an independent enzymatic assay, based on the specific detection of sulfite by sulfite reductase and compared those measurements to a modified colorimetric fuchsin-based method, specific for sulfite detection. We show here that when properly used the sulfite levels detected by the three methods can yield identical results. Furthermore, to examine the capacity of the plant to detoxify sulfite we injected sub-lethal sulfite solutions (yet, several folds higher than the basal levels) into Arabidopsis and tomato leaves and monitored the excess sulfite turnover. Within 3h of sulfite injection, more than 80% of the injected sulfite in Arabidopsis and 91% in tomato were oxidized to sulfate, demonstrating the high capacity of the sulfite oxidation mechanism/s in plants. PMID:22608526

  6. X-ray absorption spectroscopy of chicken sulfite oxidase crystals

    SciTech Connect

    George, G.N.; Pickering, I.J.; Kisker, C.

    1999-05-17

    Sulfite oxidase catalyzes the physiologically vital oxidation of sulfite to sulfate. Recently, the crystal structure of chicken sulfite oxidase has been reported at 1.9 {angstrom} resolution. In contrast to the information available from previous X-ray absorption spectroscopic studies, the active site indicated by crystallography was a mono-oxo species. Because of this the possibility that the crystals did in fact contain a reduced molybdenum species was considered in the crystallographic work. The authors report herein an X-ray absorption spectroscopic study of polycrystalline sulfite oxidase prepared in the same manner as the previous single-crystal samples, and compare this with data for frozen solutions of oxidized and reduced enzyme.

  7. Identification and biochemical characterization of Arabidopsis thaliana sulfite oxidase. A new player in plant sulfur metabolism.

    PubMed

    Eilers, T; Schwarz, G; Brinkmann, H; Witt, C; Richter, T; Nieder, J; Koch, B; Hille, R; Hänsch, R; Mendel, R R

    2001-12-14

    In mammals and birds, sulfite oxidase (SO) is a homodimeric molybdenum enzyme consisting of an N-terminal heme domain and a C-terminal molybdenum domain (EC ). In plants, the existence of SO has not yet been demonstrated, while sulfite reductase as part of sulfur assimilation is well characterized. Here we report the cloning of a plant sulfite oxidase gene from Arabidopsis thaliana and the biochemical characterization of the encoded protein (At-SO). At-SO is a molybdenum enzyme with molybdopterin as an organic component of the molybdenum cofactor. In contrast to homologous animal enzymes, At-SO lacks the heme domain, which is evident both from the amino acid sequence and from its enzymological and spectral properties. Thus, among eukaryotes, At-SO is the only molybdenum enzyme yet described possessing no redox-active centers other than the molybdenum. UV-visible and EPR spectra as well as apparent K(m) values are presented and compared with the hepatic enzyme. Subcellular analysis of crude cell extracts showed that SO was mostly found in the peroxisomal fraction. In molybdenum cofactor mutants, the activity of SO was strongly reduced. Using antibodies directed against At-SO, we show that a cross-reacting protein of similar size occurs in a wide range of plant species, including both herbacious and woody plants. PMID:11598126

  8. Carbon Monoxide-Reacting Pigment from Desulfotomaculum nigrificans and Its Possible Relevance to Sulfite Reduction

    PubMed Central

    Trudinger, P. A.

    1970-01-01

    The separation of an autoxidizable brown pigment, P582, from Desulfotomaculum nigrificans is described. It reacted with Na2S2O4 and was characterized by absorption maxima in the oxidized state at 392, 582, and 700 nm. In the presence of Na2S2O4, P582 formed complexes with CO and, under alkaline conditions, pyridine. There was no reaction with cyanide. The molecular weight of P582 was approximately 145,000, and the purest preparations contained Fe, Zn, and acid-labile sulfide but not Cu, Mo, or Mn. Preparations of P582 catalyzed the reduced methyl viologen (MVH)-linked reduction of sulfite, hydroxylamine, and nitrite but not of sulfate, thiosulfate, or nitrate. Reduced pyridine nucleotides did not substitute for MVH. A major product of the MVH-sulfite reaction was sulfide. CO partially inhibited the enzymatic activities. Sulfite, hydroxylamine, and nitrite and CO caused changes in the spectrum of Na2S2O4-reduced P582. Fe2+-chelating reagents reacted with part of the Fe of P582 and caused partial losses of labile sulfide and enzymatic activity. The spectral and CO-reacting properties of P582 were, however, unaffected by chelating agents. The reaction between P582 and chelating agents was stimulated by reducing agents. PMID:5473884

  9. The octaheme SirA catalyses dissimilatory sulfite reduction in Shewanella oneidensis MR-1

    SciTech Connect

    Shirodkar, Sheetal; Reed, Samantha B.; Romine, Margaret F.; Saffarini, Daad

    2011-01-01

    Shewanella oneidensis MR-1 is a metal reducer that uses a large number of electron acceptors that include thiosulfate, polysulfide, and sulfite. The enzyme required for thiosulfate and polysulfide respiration has been recently identified, but the mechanisms of sulfite reduction remained unexplored. Analysis of MR-1 cultures grown anaerobically with sulfite suggested that the dissimilatory sulfite reductase catalyzes six-electron reduction of sulfite to sulfide. Reduction of sulfite required menaquinones and c cytochromes but appeared to be independent of the intermediate electron carrier CymA. Furthermore, the terminal sulfite reductase, SirA, was identified as an octaheme c cytochrome with an atypical heme binding site that represents a new class of sulfite reductases. The sirA locus was identified in the genomes of several sequenced Shewanella genomes, and its presence appears to be linked to the ability of these organisms to reduce sulfite under anaerobic conditions.

  10. A fast and sensitive HPLC method for sulfite analysis in food based on a plant sulfite oxidase biosensor.

    PubMed

    Theisen, S; Hänsch, R; Kothe, L; Leist, U; Galensa, R

    2010-09-15

    A reliable and sensitive analysis of sulfites in food is essential in food monitoring. However, the established methods exhibit deficiencies in the very low concentration ranges (below 10 mg/L SO(2)), especially with more complex food matrices. With a focus on these challenges, an HPLC method with immobilized enzyme reactor (HPLC-IMER) for the analysis of sulfites in food was optimized and compared to a standard method. A modulated sample preparation procedure and the use of a novel sulfite oxidase from Arabidopsis thaliana were explored to make the method applicable for most food samples. The plant sulfite oxidase turned out to be superior to the commercially available animal sulfite oxidase in terms of detection limit (0.01 mg/L SO(2)), linear range (0.04-20 mg/L SO(2)) and stability. In a small scale comparison within our laboratory, as well as in a standardized proficiency testing, the HPLC-IMER was compared to an established distillative method. The enzyme-based method is not only more sensitive and specific, it also yields higher sulfite recoveries in almost all samples while exhibiting better statistic method parameters.

  11. Cloning and characterization of sulfite dehydrogenase, two c-type cytochromes, and a flavoprotein of Paracoccus denitrificans GB17: essential role of sulfite dehydrogenase in lithotrophic sulfur oxidation.

    PubMed

    Wodara, C; Bardischewsky, F; Friedrich, C G

    1997-08-01

    A 13-kb genomic region of Paracoccus dentrificans GB17 is involved in lithotrophic thiosulfate oxidation. Adjacent to the previously reported soxB gene (C. Wodara, S. Kostka, M. Egert, D. P. Kelly, and C. G. Friedrich, J. Bacteriol. 176:6188-6191, 1994), 3.7 kb were sequenced. Sequence analysis revealed four additional open reading frames, soxCDEF. soxC coded for a 430-amino-acid polypeptide with an Mr of 47,339 that included a putative signal peptide of 40 amino acids (Mr of 3,599) with a RR motif present in periplasmic proteins with complex redox centers. The mature soxC gene product exhibited high amino acid sequence similarity to the eukaryotic molybdoenzyme sulfite oxidase and to nitrate reductase. We constructed a mutant, GBsoxC delta, carrying an in-frame deletion in soxC which covered a region possibly coding for the molybdenum cofactor binding domain. GBsoxC delta was unable to grow lithoautotrophically with thiosulfate but grew well with nitrate as a nitrogen source or as an electron acceptor. Whole cells and cell extracts of mutant GBsoxC delta contained 10% of the thiosulfate-oxidizing activity of the wild type. Only a marginal rate of sulfite-dependent cytochrome c reduction was observed from cell extracts of mutant GBsoxC delta. These results demonstrated that sulfite dehydrogenase was essential for growth with thiosulfate of P. dentrificans GB17. soxD coded for a periplasmic diheme c-type cytochrome of 384 amino acids (Mr of 39,983) containing a putative signal peptide with an Mr of 2,363. soxE coded for a periplasmic monoheme c-type cytochrome of 236 amino acids (Mr of 25,926) containing a putative signal peptide with an Mr of 1,833. SoxD and SoxE were highly identical to c-type cytochromes of P. denitrificans and other organisms. soxF revealed an incomplete open reading frame coding for a peptide of 247 amino acids with a putative signal peptide (Mr of 2,629). The deduced amino acid sequence of soxF was 47% identical and 70% similar to the sequence

  12. Estimate of intake of sulfites in the Belgian adult population.

    PubMed

    Vandevijvere, S; Temme, E; Andjelkovic, M; De Wil, M; Vinkx, C; Goeyens, L; Van Loco, J

    2010-08-01

    An exposure assessment was performed to estimate the usual daily intake of sulfites in the Belgian adult population. Food consumption data were retrieved from the national food consumption survey. In a first step, individual food consumption data were multiplied with the maximum permitted use levels for sulfites, expressed as sulphur dioxide, per food group (Tier 2). In a second step, on the basis of a literature review of the occurrence of sulfites in different foods, the results of the Tier 2 exposure assessment and available occurrence data from the control programme of the competent authority, a refined list of foods was drafted for the quantification of sulphite. Quantification of sulphite was performed by a high-performance ion chromatography method with eluent conductivity detector in beers and potato products. Individual food consumption data were then multiplied with the actual average concentrations of sulfite per food group, or the maximum permitted levels in case actual levels were not available (partial Tier 3). Usual intakes were calculated using the Nusser method. The mean intake of sulfites was 0.34 mg kg(-1) bw day(-1) (Tier 2), corresponding to 49% of the acceptable daily intake (ADI) and 0.19 mg kg(-1) bw day(-1), corresponding to 27% of the ADI (partial Tier 3). The food group contributing most to the intake of sulfites was wines. The results showed that the intake of sulfites is likely to be below the ADI in Belgium. However, there are indications that high consumers of wine have an intake around the ADI.

  13. Biodesulfurization of flue gases and other sulfate/sulfite waste streams using immobilized mixed sulfate-reducing bacteria.

    PubMed

    Selvaraj, P T; Little, M H; Kaufman, E N

    1997-01-01

    Sulfur dioxide (SO2) is one of the major pollutants in the atmosphere that cause acid rain. Microbial processes for reducing SO2 to hydrogen sulfide (H2S) have previously been demonstrated by utilizing mixed cultures of sulfate-reducing bacteria (SRB) with municipal sewage digest as the carbon and energy source. To maximize the productivity of the bioreactor for SO2 reduction in this study, various immobilized cell bioreactors were investigated: a stirred tank with SRB flocs and columnar reactors with cells immobilized in either potassium-carrageenan gel matrix or polymeric porous BIO-SEP beads. The maximum volumetric productivity for SO2 reduction in the continuous stirred-tank reactor (CSTR) with SRB flocs was 2.1 mmol of SO2/(h.L). The potassium-carrageenan gell matrix used for cell immobilization was not durable at feed sulfite concentrations greater than 2000 mg/L (1.7 mmol/(h.L)). A columnar reactor with mixed SRB cells that had been allowed to grow into highly stable BIO-SEP polymeric beads exhibited the highest sulfite conversion rates, in the range 16.5 mmol/(h.L) (with 100% conversion) to 20 mmol/(h.L) (with 95% conversion). The average specific activity for sulfite reduction in the column, in terms of dry weight of SRB biomass, was 9.5 mmol of sulfite/(h.g). In addition to flue gas desulfurization, potential applications of this microbial process include the treatment of sulfate/sulfite-laden wastewater from the pulp and paper, petroleum, mining, and chemical industries.

  14. Potential treatment of transthyretin-type amyloidoses by sulfite.

    PubMed

    Altland, K; Winter, P

    1999-09-01

    Familial amyloidotic polyneuropathy (FAP) and senile systemic amyloidosis (SSA) are characterized by systemic extracellular deposition of insoluble transthyretin (TTR) fibrils. While only normal TTR is found in fibrils from SSA patients who predominantly suffer from cardiomyopathy, autosomal dominant FAP preferentially affects peripheral nerves and heart and is associated with so-called amyloidogenic mutations of this protein, giving rise to TTR forms of decreased stability. Using isoelectric focusing in urea gradients we were able to demonstrate a stabilizing effect of sulfite on TTR monomers and tetramers, as well as an increase in the tetramer/monomer ratio. We demonstrate that this ratio, which is decreased in FAP patients, can be increased to beyond normal levels. We show that doses of sulfite which are tolerable in vivo produce a significant increase in the tetramer/monomer ratio and postulate that sulfite may be a potent drug for delaying the onset and progress of FAP and SSA.

  15. Cellulose extraction from orange peel using sulfite digestion reagents.

    PubMed

    Bicu, Ioan; Mustata, Fanica

    2011-11-01

    Orange peel (OP) was used as raw material for cellulose extraction. Two different pulping reagents were used, sodium sulfite and sodium metabisulfite. The effect of the main process parameters, sulfite agent dosage and reaction duration, on cellulose yield was investigated. A central composite rotatable design involving two variables at five levels and response surface methodology were used for the optimization of cellulose recovery. Other two invariable parameters were reaction temperature and hydromodulus. The optimum yields, referred to the weight of double extracted OP, were 40.4% and 45.2% for sodium sulfite and sodium metabisulfite digestions, respectively. The crude celluloses were bleached with hypochlorite and oxygen. The physicochemical characterization data of these cellulose materials indicate good levels of purity, low crystallinities, good whitenesses, good water retention and moderate molecular weights. According to these specific properties the recovered celluloses could be used as fillers, water absorbents, or as raw materials for cellulose derivatives.

  16. Analysis of commercial proanthocyanidins. Part 2: An electrospray mass spectrometry investigation into the chemical composition of sulfited quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood extract.

    PubMed

    Venter, Pieter B; Senekal, Nadine D; Amra-Jordaan, Maryam; Bonnet, Susan L; Van der Westhuizen, Jan H

    2012-06-01

    Proanthocyanidins (PACs) are natural plant-derived polymers used in leather tanning, wood adhesives, water purification, and mud additives for oil drilling. Quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood and mimosa (Acacia mearnsii) bark extracts are the major industrial sources of PACs. These commercial extracts are often sulfited via treatment with sodium hydrogen sulfite to reduce their viscosity and increase their solubility in water. An ESI-MS investigation into the molecular composition of sulfited (cold-water-soluble) quebracho heartwood extract indicates that sulfitation of the PACs occurs via S(N)2 attack of a sulfite ion at both C-2 and C-4 of the constituent flavan-3-ol monomer extender units. Attack at C-2 leads to the opening of the pyran ring. This releases an additional electron-donating phenolic hydroxy group on the A-ring and renders the extract more nucleophilic and suitable for the manufacturing of adhesives. Attack at C-4 leads to interflavanyl bond fission and decrease of the PAC oligomer chain length. The introduction of sulfonic acid moieties at C-2 or C-4 increases the polarity and water solubility of the hot water soluble (unsulfited) extract and transforms it into a cold-water-soluble extract. PMID:22513010

  17. The rate of sulfite oxidation in seawater

    NASA Astrophysics Data System (ADS)

    Zhang, Jia-Zhong; Millero, Frank J.

    1991-03-01

    The rate of oxidation of sulfite, S( IV), in seawater was measured as a function of pH (4.0- 8.5), temperature ( 15-45°C), and salinity (0-35). The observed rate constant, k, in seawater at a pH = 8.2 was found to be second order with respect to S( IV) and half order with respect to oxygen: -d[S(IV)]/dt = k[S(IV)] 2[O 2] 0.5. The resulting values of k ( M-1.5 min -1) have been fitted to a function of ionic strength, I, and temperature, T(K): logk = 19.54 - 5069.47/ T + 14.74 I0.5 - 2.93 I - 2877.0 I0.5/ T, and the standard error is 0.05 in log k. The energy of activation was found to be a function of salinity and has a value of 140 ± 6 kJ mol -1atS = 35. The rates measured in 0.57 M NaCl were found to be higher than the rates in seawater. Measurements made in the major sea salts indicate that Ca 2+, Mg 2+, and SO 42- added to NaCl cause the decrease. Measurements made in artificial seawater (Na +, Mg 2+, Ca 2+, Cl -, and SO 42-) were found to be in good agreement with the measurements in real seawater. The rate increased from pH 4 to a maximum at pH 6.5 and decreased at higher pH. The effect of pH on the rates was attributed to the rate-determining step involving the combination of HSO 3- and SO 32-. This yields k = k″ αHSO3- αSO32- where α i is the molar fraction of species i. Values of k″ equal to 6.66 ± 0.06 and 6.17 ± 0.17 were found for NaCl and seawater, respectively. The larger range of k″ in seawater is due to it being a function of pH. The addition of Mn 2+ was found to increase the rate apparently due to the formation of MnSO 3. Additions of Fe 3+ and Fe 2+ have a catalytic effect only before they hydrolyze to colloidal iron.

  18. 40 CFR 415.200 - Applicability; description of the sodium sulfite production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sodium sulfite production subcategory. 415.200 Section 415.200 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Sodium Sulfite Production Subcategory § 415.200 Applicability; description of the sodium... the production of sodium sulfite by reacting sulfur dioxide with sodium carbonate....

  19. 40 CFR 415.200 - Applicability; description of the sodium sulfite production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sodium sulfite production subcategory. 415.200 Section 415.200 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Sodium Sulfite Production Subcategory § 415.200 Applicability; description of the sodium... the production of sodium sulfite by reacting sulfur dioxide with sodium carbonate....

  20. 40 CFR 415.200 - Applicability; description of the sodium sulfite production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sodium sulfite production subcategory. 415.200 Section 415.200 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Sodium Sulfite Production Subcategory § 415.200 Applicability; description of the sodium... the production of sodium sulfite by reacting sulfur dioxide with sodium carbonate....

  1. 40 CFR 415.200 - Applicability; description of the sodium sulfite production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... sodium sulfite production subcategory. 415.200 Section 415.200 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Sodium Sulfite Production Subcategory § 415.200 Applicability; description of the sodium... the production of sodium sulfite by reacting sulfur dioxide with sodium carbonate....

  2. Polyphenols content, phenolics profile and antioxidant activity of organic red wines produced without sulfur dioxide/sulfites addition in comparison to conventional red wines.

    PubMed

    Garaguso, Ivana; Nardini, Mirella

    2015-07-15

    Wine exerts beneficial effects on human health when it is drunk with moderation. Nevertheless, wine may also contain components negatively affecting human health. Among these, sulfites may induce adverse effects after ingestion. We examined total polyphenols and flavonoids content, phenolics profile and antioxidant activity of eight organic red wines produced without sulfur dioxide/sulfites addition in comparison to those of eight conventional red wines. Polyphenols and flavonoids content were slightly higher in organic wines in respect to conventional wines, however differences did not reach statistical significance. The phenolic acids profile was quite similar in both groups of wines. Antioxidant activity was higher in organic wines compared to conventional wines, although differences were not statistically significant. Our results indicate that organic red wines produced without sulfur dioxide/sulfites addition are comparable to conventional red wines with regard to the total polyphenols and flavonoids content, the phenolics profile and the antioxidant activity.

  3. Hydrogen production via photolytic oxidation of aqueous sodium sulfite solutions.

    PubMed

    Huang, Cunping; Linkous, Clovis A; Adebiyi, Olawale; T-Raissi, Ali

    2010-07-01

    Sulfur dioxide (SO(2)) emission from coal-burning power plants and refinery operations has been implicated as a cause of acid rain and other air pollution related problems. The conventional treatment of SO(2)-contaminated air consists of two steps: SO(2) absorption using an aqueous sodium hydroxide solution, forming aqueous sodium sulfite (Na(2)SO(3)), and Na(2)SO(3) oxidation via air purging to produce sodium sulfate (Na(2)SO(4)). In this process, the potential energy of SO(2) is lost. This paper presents a novel ultraviolet (UV) photolytic process for production of hydrogen from aqueous Na(2)SO(3) solutions. The results show that the quantum efficiency of hydrogen production can reach 14.4% under illumination from a low pressure mercury lamp. The mechanism occurs via two competing reaction pathways that involve oxidation of SO(3)(2-) to SO(4)(2-) directly and through the dithionate (S(2)O(6)(2-)) ion intermediate. The first route becomes dominant once a photostationary state for S(2)O(6)(2-) is established. The initial pH of Na(2)SO(3) solution plays an important role in determining both the hydrogen production rate and the final products of the photolytic oxidation. At initial solution pH of 9.80 Na(2)SO(3) photo-oxidation generates Na(2)SO(4) as the final reaction product, while Na(2)S(2)O(6) is merely a reaction intermediate. The highest hydrogen production rate occurs when the initial solution pH is 7.55. Reduction in the initial solution pH to 5.93 results in disproportionation of HSO(3)(-) to elemental sulfur and SO(4)(2-) but no hydrogen production.

  4. Comparison of four different methods for the determination of sulfites in foods marketed in South Korea.

    PubMed

    Lim, Ho-Soo; Park, Sung-Kwan; Kim, So-Hee; Song, Sung-Bong; Jang, Su-Jin; Kim, Meehye

    2014-01-01

    Sulfites in foods were analysed using four methods: optimised Monier-Williams (official method), modified Rankine, HPLC and ion-exchange chromatography (IEC). The modified Rankine and HPLC methods were performed according to the previously reported methods but with some modifications. The IEC method was carried out through a combination of a modified Rankine apparatus and an anion-exchange column for the first time. In false-positive response tests, false-positive results with acetic acid and propionic acid were not observed in the modified Rankine, HPLC or IEC methods, unlike the optimised Monier-Williams method. All methods were evaluated for accuracy, precision and simple correlations. Modified Rankine, HPLC and IEC methods were determined to be suitable for foods with less than 10 mg kg(-1) of sulfur dioxide (SO₂). The modified Rankine and HPLC methods were suggested to be the most appropriate for the determination of sulfites in foods due to their high correlation coefficient with the optimised Monier-Williams method (R(2) = 0.9138 and 0.9011, respectively).

  5. Reduction of Fe(III) with sulfite in natural waters

    NASA Astrophysics Data System (ADS)

    Millero, F. J.; Gonzalez-Davila, M.; Santana-Casiano, J. M.

    1995-04-01

    The Fe(III) in marine aerosols and rainwaters can be reduced to Fe(II) by photochemical processes and by reactions with sulfite. In this paper, measurements of the rates of reduction of nanomolar levels of Fe(III) with sulfite (without O2) have been determined in NaCl and seawater solutions as a function of temperature (0° to 40°C), pH (2 to 6.8), ionic strength (I = 0.1 to 6 M), and composition (Na+, Mg2+, Ca2+, F-, Cl-, Br-, HCO3-, SO42-). The overall rate constant (k, M-1 min-1) for the reaction, Fe>(III>)+S>(IV>)>→k products, is given by d[Fe(III)]/dt = -k[Fe(III)] [S(IV)]. The reaction was found to be first order with respect to Fe(III) and S(IV). The rate constants as a function of pH increased from a pH = 2 to 4 and decreased at higher pH. The effect of temperature and ionic strength on the rates could be represented by log k = log k0 + AI0.5/(1 + I0.5), where A = -1.1 in NaCl and -2.2 in seawater and log k0 = 25.39 - 6,323/T. The energy of activation was found by 121±6 kJ mol-1. The measured rates in seawater as a function of salinity were lower than the rates in NaCl at the same ionic strength. Measurements in NaCl solutions with added sea-salt ions (Mg2+, Ca2+, F-, Br-, and SO42-) at pH = 3.5 indicate that the formation of inert FeF2+ may be responsible for the lower rates. The effect of changes in the composition on the rates was interpreted by examining the speciation of Fe(III) and S(IV). This analysis indicates that the rate-determining steps from a pH of 2.5 to 4.0 are FeOH2+ + HSO3- ↔ HOFeSO3H + and HOFeSO3H+>⟶k1FeOH++HSO3· and at pH of 4 to 6, the reactions Fe(OH)2+ + HSO3- ↔ (HO)2FeSO3H and >(HO>)2FeSO3H>⟶k2Fe>(OH>)2+HSO3· become important. The changes in the concentration of FeOH2+ and HSO3- as a function of pH and composition can account for most of the changes in the rates. These kinetic studies indicate that the rates of reduction of Fe(III) with S(IV) in acidic water droplets at natural levels of S(IV) may be an important

  6. Domain evolution and functional diversification of sulfite reductases.

    PubMed

    Dhillon, Ashita; Goswami, Sulip; Riley, Monica; Teske, Andreas; Sogin, Mitchell

    2005-02-01

    Sulfite reductases are key enzymes of assimilatory and dissimilatory sulfur metabolism, which occur in diverse bacterial and archaeal lineages. They share a highly conserved domain "C-X5-C-n-C-X3-C" for binding siroheme and iron-sulfur clusters that facilitate electron transfer to the substrate. For each sulfite reductase cluster, the siroheme-binding domain is positioned slightly differently at the N-terminus of dsrA and dsrB, while in the assimilatory proteins the siroheme domain is located at the C-terminus. Our sequence and phylogenetic analysis of the siroheme-binding domain shows that sulfite reductase sequences diverged from a common ancestor into four separate clusters (aSir, alSir, dsr, and asrC) that are biochemically distinct; each serves a different assimilatory or dissimilatory role in sulfur metabolism. The phylogenetic distribution and functional grouping in sulfite reductase clusters (dsrA and dsrB vs. aSiR, asrC, and alSir) suggest that their functional diversification during evolution may have preceded the bacterial/archaeal divergence.

  7. 21 CFR 130.9 - Sulfites in standardized food.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, and the refinements of the... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Sulfites in standardized food. 130.9 Section 130.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  8. 21 CFR 130.9 - Sulfites in standardized food.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, and the refinements of the... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Sulfites in standardized food. 130.9 Section 130.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  9. 21 CFR 130.9 - Sulfites in standardized food.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, and the refinements of the... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Sulfites in standardized food. 130.9 Section 130.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  10. Mechanism of the Ferrocyanide-Iodate-Sulfite Oscillatory Chemical Reaction.

    PubMed

    Horváth, Viktor; Epstein, Irving R; Kustin, Kenneth

    2016-03-31

    Existing models of the ferrocyanide-iodate-sulfite (FIS) reaction seek to replicate the oscillatory pH behavior that occurs in open systems. These models exhibit significant differences in the amplitudes and waveforms of the concentration oscillations of such intermediates as I(-), I3(-), and Fe(CN)6(3-) under identical conditions and do not include several experimentally found intermediates. Here we report measurements of sulfite concentrations during an oscillatory cycle. Knowing the correct concentration of sulfite over the course of a period is important because sulfite is the main component that determines the buffer capacity, the pH extrema, and the amount of oxidizer (iodate) required for the transition to low pH. On the basis of this new result and recent experimental findings on the rate laws and intermediates of component processes taken from the literature, we propose a mass action kinetics model that attempts to faithfully represent the chemistry of the FIS reaction. This new comprehensive mechanism reproduces the pH oscillations and the periodic behavior in [Fe(CN)6(3-)], [I3(-)], [I(-)], and [SO3(2-)]T with characteristics similar to those seen in experiments in both CSTR and semibatch arrangements. The parameter ranges at which stationary and oscillatory behavior is exhibited also show good agreement with those of the experiments.

  11. Stabilized gravimetric standard for sulfites and sulfur dioxide

    SciTech Connect

    Irgum, K.

    1985-06-01

    Preparation of standards in the analysis of sulfites and sulfur dioxide can be a problem, especially if higher accuracy is needed, as the sulfite salts commonly used to prepare such standards are not available with guaranteed assays due to oxidation. They must therefore be assayed by titrimetry immediately before use. Sulfate originating from oxidation of the sulfite salt can also be troublesome if a mixed sulfite and sulfate standard is to be prepared for, i.e., ion chromatrography. Another compound that has been used as standard for tetravalent sulfur is sodium hydroxymethanesulfonate (HMS). Aldehyde addition compounds are also used for stabilization of sulfur dioxide after sampling. Stability of HMS toward oxidation is good, but commercially available preparations are practical grade and must be purified before use. HMS is furthermore hygroscopic and decomposes on heating. These are drawbacks which make it far from ideal as a standard substance. In situ preparation is performed by purging a buffered formaldehyde solution with SO/sub 2/(g). Stabilities of both stock solutions and dilutions are checked. 9 references, 2 figures, 2 tables.

  12. Growth of spherulites of strontium and barium sulfites

    NASA Astrophysics Data System (ADS)

    Matsuno, T.; Koishi, M.

    1989-03-01

    The spherulites of SrSO 3 and BaSO 3 were synthesized in agar-agar gels (0-40°C). The reactants are sodium sulfite and the chloride of the respective metals. Each spherulite consists of fibrous crystals which are arranged minutely in a radial manner from the center. A linear relation was recognized between (mean diameter) 2 and reaction time in the same manner as the CaSO 3 · 0.5H 2O spherulite reported in our previous paper. The slopes of the lines, namely the growth rates of the spherulites, were greater in the order of calcium sulfite > strontium sulfite > barium sulfite. The ratio of (mean diameter) 2/time was dependent upon the concentration of the agar-agar gel (0.5%-2.0%) and the reaction temperature (0-40°C); the ratios decreased linearly with an increase of the gel concentration and increased with an increase of temperature.

  13. Domain Evolution and Functional Diversification of Sulfite Reductases

    NASA Astrophysics Data System (ADS)

    Dhillon, Ashita; Goswami, Sulip; Riley, Monica; Teske, Andreas; Sogin, Mitchell

    2005-02-01

    Sulfite reductases are key enzymes of assimilatory and dissimilatory sulfur metabolism, which occur in diverse bacterial and archaeal lineages. They share a highly conserved domain "C-X5-C-n-C-X3-C" for binding siroheme and iron-sulfur clusters that facilitate electron transfer to the substrate. For each sulfite reductase cluster, the siroheme-binding domain is positioned slightly differently at the N-terminus of dsrA and dsrB, while in the assimilatory proteins the siroheme domain is located at the C-terminus. Our sequence and phylogenetic analysis of the siroheme-binding domain shows that sulfite reductase sequences diverged from a common ancestor into four separate clusters (aSir, alSir, dsr, and asrC) that are biochemically distinct; each serves a different assimilatory or dissimilatory role in sulfur metabolism. The phylogenetic distribution and functional grouping in sulfite reductase clusters (dsrA and dsrB vs. aSiR, asrC, and alSir) suggest that their functional diversification during evolution may have preceded the bacterial/archaeal divergence.

  14. 21 CFR 130.9 - Sulfites in standardized food.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, and the refinements of the... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Sulfites in standardized food. 130.9 Section 130.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  15. 21 CFR 130.9 - Sulfites in standardized food.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, and the refinements of the... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Sulfites in standardized food. 130.9 Section 130.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  16. Clonal mast cell activation syndrome with anaphylaxis to sulfites.

    PubMed

    Cifuentes, Liliana; Ring, Johannes; Brockow, Knut

    2013-01-01

    Sulfites are rarely suspected as causative agents of immediate-type hypersensitivity. We report on a 49-year-old male patient who developed recurrent severe hypotension after food ingestion. A diagnosis of monoclonal mast cell activation syndrome was established. In the double-blind, placebo-controlled food challenge, the patient reacted to potassium metabisulfite with anaphylaxis.

  17. Preparation, Characterization, and Selectivity Study of Mixed-Valence Sulfites

    ERIC Educational Resources Information Center

    Silva, Luciana A.; de Andrade, Jailson B.

    2010-01-01

    A project involving the synthesis of an isomorphic double sulfite series and characterization by classical inorganic chemical analyses is described. The project is performed by upper-level undergraduate students in the laboratory. This compound series is suitable for examining several chemical concepts and analytical techniques in inorganic…

  18. The antibrowning agent sulfite inactivates Agaricus bisporus tyrosinase through covalent modification of the copper-B site.

    PubMed

    Kuijpers, Tomas F M; Gruppen, Harry; Sforza, Stefano; van Berkel, Willem J H; Vincken, Jean-Paul

    2013-12-01

    Sulfite salts are widely used as antibrowning agents in food processing. Nevertheless, the exact mechanism by which sulfite prevents enzymatic browning has remained unknown. Here, we show that sodium hydrogen sulfite (NaHSO3) irreversibly blocks the active site of tyrosinase from the edible mushroom Agaricus bisporus, and that the competitive inhibitors tropolone and kojic acid protect the enzyme from NaHSO3 inactivation. LC-MS analysis of pepsin digests of NaHSO3 -treated tyrosinase revealed two peptides showing a neutral loss corresponding to the mass of SO3 upon MS(2) fragmentation. These peptides were found to be homologous peptides containing two of the three histidine residues that form the copper-B-binding site of mushroom tyrosinase isoform PPO3 and mushroom tyrosinase isoform PPO4, which were both present in the tyrosinase preparation used. Peptides showing this neutral loss behavior were not found in the untreated control. Comparison of the effects of NaHSO3 on apo-tyrosinase and holo-tyrosinase indicated that inactivation is facilitated by the active site copper ions. These data provide compelling evidence that inactivation of mushroom tyrosinase by NaHSO3 occurs through covalent modification of a single amino-acid residue, probably via addition of HSO3(-) to one of the copper-coordinating histidines in the copper-B site of the enzyme.

  19. The antibrowning agent sulfite inactivates Agaricus bisporus tyrosinase through covalent modification of the copper-B site.

    PubMed

    Kuijpers, Tomas F M; Gruppen, Harry; Sforza, Stefano; van Berkel, Willem J H; Vincken, Jean-Paul

    2013-12-01

    Sulfite salts are widely used as antibrowning agents in food processing. Nevertheless, the exact mechanism by which sulfite prevents enzymatic browning has remained unknown. Here, we show that sodium hydrogen sulfite (NaHSO3) irreversibly blocks the active site of tyrosinase from the edible mushroom Agaricus bisporus, and that the competitive inhibitors tropolone and kojic acid protect the enzyme from NaHSO3 inactivation. LC-MS analysis of pepsin digests of NaHSO3 -treated tyrosinase revealed two peptides showing a neutral loss corresponding to the mass of SO3 upon MS(2) fragmentation. These peptides were found to be homologous peptides containing two of the three histidine residues that form the copper-B-binding site of mushroom tyrosinase isoform PPO3 and mushroom tyrosinase isoform PPO4, which were both present in the tyrosinase preparation used. Peptides showing this neutral loss behavior were not found in the untreated control. Comparison of the effects of NaHSO3 on apo-tyrosinase and holo-tyrosinase indicated that inactivation is facilitated by the active site copper ions. These data provide compelling evidence that inactivation of mushroom tyrosinase by NaHSO3 occurs through covalent modification of a single amino-acid residue, probably via addition of HSO3(-) to one of the copper-coordinating histidines in the copper-B site of the enzyme. PMID:24112416

  20. Desulfurization of flue gases with complete sulfite oxidation

    SciTech Connect

    Lurie, D.

    1983-05-03

    Flue gas containing sulfur dioxide is purified (And the sulfur content thereof is recovered in elemental form) by scrubbing the gas with aqueous sodium aluminate-sodium hydroxide solution thereby forming an underflow suspension consisting essentially of sodium and aluminum sulfites and sulfates and fly ash; oxidizing the sulfites to sulfates; evaporating the free water present; reducing the resulting apparently dry mixture of sodium and aluminum sulfates by the action of reactive hydrogen and a carbonaceous reducing agent thereby forming a solid mixture of a sodium oxide and sodium aluminate and a gaseous mixture comprising sulfur dioxide, sulfur, and hydrogen sulfide; condensing said sulfur; and inter-reacting said sulfur dioxide and hydrogen sulfide to provide elemental sulfur. The solid mixture is dissolved in water to regenerate the scrubbing solution, which is then recycled. The solution is filtered at any convenient point to remove fly ash and any other solids present.

  1. Desulfurization of flue gases with complete sulfite oxidation

    SciTech Connect

    Lurie, D.

    1981-12-22

    Flue gas containing sulfur dioxide is purified (and the sulfur content thereof is recovered in elemental form) by scrubbing the gas with aqueous sodium aluminate-sodium hydroxide solution thereby forming an underflow suspension consisting essentially of sodium and aluminum sulfites and sulfates and fly ash; oxidizing the sulfites to sulfates; evaporating the free water present; reducing the resulting apparently dry mixture of sodium and aluminum sulfates by the action of reactive hydrogen and a carbonaceous reducing agent thereby forming a solid mixture of a sodium oxide and sodium aluminate and a gaseous mixture comprising sulfur dioxide, sulfur, and hydrogen sulfide; condensing said sulfur; and inter-reacting said sulfur dioxide and hydrogen sulfide to provide elemental sulfur. The solid mixture is dissolved in water to regenerate the scrubbing solution, which is then recycled. The solution is filtered at any convenient point to remove fly ash and any other solids present.

  2. Studies on the sulfite reduction test for clostridia.

    PubMed

    Kawabata, N

    1980-01-01

    Peptone-yeast extract (PY) medium containing 0.035% ferric ammonium citrate as an indicator, 0.05% sulfite as a substrate, 0.05% cysteine as a reducer and 0.5% glucose was found to be suitable for observing the sulfite reduction test. The effect of added cysteine on the test was suppressed by the addition of glucose. In cultures of bacteria grown for 2 days at 37 C in medium containing the above ingredients, 121 among 132 strains of clostridia, including 86 strains of Clostridium perfringens, gave a positive reaction. Although some strains of Salmonella and Proteus were positive, the specificity of the test for clostridia was thought to be relatively high. Positive reactions in a resting cell system were limited to some species of clostridia.

  3. Fermentation to ethanol of pentose-containing spent sulfite liquor

    SciTech Connect

    Yu, S.; Wayman, M.; Parekh, S.K.

    1987-01-01

    Ethanolic fermentation of spent sulfite liquor with ordinary bakers' yeast is incomplete because of this yeast cannot ferment the pentose sugars in the liquor. This results in poor alcohol yields, and a residual effluent problem. By using the yeast Candida shehatae (R) for fermentation of the spent sulfite liquor from a large Canadian alcohol-producing sulfite pulp and paper mill, pentoses as well as hexoses were fermented nearly completely, alcohol yields were raised by 33%, and sugar removal increased by 46%. Inhibitors were removed prior to fermentation by steam stripping. Major benefits were obtained by careful recycling of this yeast, which was shown to be tolerant both of high sugar concentrations and high alcohol concentrations. When sugar concentrations over 250 g/L (glucose:xylose 70:30) were fermented, ethanol became an inhibitor when its concentration reached over 90 g/L. However, when the ethanol was removed by low-temperature vacuum distillation, fermentation continued and resulted in a yield of 0.50 g ethanol/g sugar consumed. Further improvement was achieved by combining enzyme saccharification of sugar oligomers with fermentation. This yeast is able to ferment both hexoses and pentoses simultaneously, efficiently, and rapidly.

  4. Different mechanisms of resistance modulate sulfite tolerance in wine yeasts.

    PubMed

    Nadai, Chiara; Treu, Laura; Campanaro, Stefano; Giacomini, Alessio; Corich, Viviana

    2016-01-01

    From a technological point of view, yeast resistance to sulfite is of great interest and represents an important technological character for winemaking. Several mechanisms are involved, and strain-dependent strategies to obtain SO2 resistance can deeply influence wine quality, although this choice is less relevant in determining the technological performance of the strain during fermentation. In this study, to better understand the strain-specific mechanisms of resistance, 11 Saccharomyces cerevisiae strains, whose genomes have been previously sequenced, were selected. Their attitude towards sulfites, in terms of resistance and production, was evaluated, and RNA-sequencing of four selected strains was performed during fermentation process in synthetic grape must in the presence of SO2. Results demonstrated that at molecular level, the physical effect of SO2 triggered multiple stress responses in the cell and high tolerance to general enological stressing condition increased SO2 resistance. Adaptation mechanism due to high basal gene expression level rather than specific gene induction in the presence of sulfite seemed to be responsible in modulating strain resistance. This mechanism involved higher basal gene expression level of specific cell wall proteins, enzymes for lipid biosynthesis, and enzymes directly involved in SO2 assimilation pathway and efflux. PMID:26615396

  5. Different mechanisms of resistance modulate sulfite tolerance in wine yeasts.

    PubMed

    Nadai, Chiara; Treu, Laura; Campanaro, Stefano; Giacomini, Alessio; Corich, Viviana

    2016-01-01

    From a technological point of view, yeast resistance to sulfite is of great interest and represents an important technological character for winemaking. Several mechanisms are involved, and strain-dependent strategies to obtain SO2 resistance can deeply influence wine quality, although this choice is less relevant in determining the technological performance of the strain during fermentation. In this study, to better understand the strain-specific mechanisms of resistance, 11 Saccharomyces cerevisiae strains, whose genomes have been previously sequenced, were selected. Their attitude towards sulfites, in terms of resistance and production, was evaluated, and RNA-sequencing of four selected strains was performed during fermentation process in synthetic grape must in the presence of SO2. Results demonstrated that at molecular level, the physical effect of SO2 triggered multiple stress responses in the cell and high tolerance to general enological stressing condition increased SO2 resistance. Adaptation mechanism due to high basal gene expression level rather than specific gene induction in the presence of sulfite seemed to be responsible in modulating strain resistance. This mechanism involved higher basal gene expression level of specific cell wall proteins, enzymes for lipid biosynthesis, and enzymes directly involved in SO2 assimilation pathway and efflux.

  6. A simple levulinate-based ratiometric fluorescent probe for sulfite with a large emission shift.

    PubMed

    Liu, Caiyun; Wu, Huifang; Yang, Wen; Zhang, Xiaoling

    2014-01-01

    A simple 4-hydroxynaphthalimide-derived colorimetric and ratiometric fluorescent probe (1) containing a receptor of levulinate moiety was designed and synthesized to monitor sulfite. Probe 1 could quantificationally detect sulfite by a ratiometric fluorescence spectroscopy method with high selectivity and sensitivity. Specially, probe 1 exhibited a 100 nm red-shifted absorption spectrum along with the color changes from colorless to yellow, and 103 nm red-shifted emission spectra upon the addition of sulfite. Thus, 1 can serve as a "naked-eye" probe for sulfite. Further, the recognition mechanism of probe 1 for sulfite was confirmed using nuclear magnetic resonance and electrospray ionization mass spectrometry. Also, the preliminary practical application demonstrated that our proposed probe provided a promising method for the determination of sulfite. PMID:24813958

  7. Methods for the recovery of sulfur components from flue gas and recycle sodium sulfite by reduction-smelting and carbonating to strip hydrogen sulfide

    SciTech Connect

    Farin, W.G.

    1980-12-23

    An improved method for recovering sulfur from flue gas which contains sulfur dioxide formed from burning sulfur containing fuels is disclosed. The method first involves the reduction burning of auxilary fuel in the presence of sodium sulfite to convert it to smelt containing sodium sulfide and sodium carbonate. The smelt is dissolved, and the solution reacted with carbon dioxide, hydrogen sulfide and water vapor forming sodium hydrosulfide. The sodium hydrosulfide is reacted with a high concentration of recycled sodium bicarbonate and stripped with carbon dioxide to form sodium carbonate and release the sulfides as hydrogen sulfide from the stripper. The hydrogen sulfide released is then converted to sulfur dioxide, sulfuric acid or elemental sulfur. Pressurized carbon dioxide is used for pressure carbonation of recycled solution from the stripper to convert the sodium carbonate to the high concentration of recycled sodium bicarbonate used for stripping. The sodium carbonate and sodium bicarbonate from the stripper are reacted under pressure with sodium bisulfite in a decarbonator to form sodium sulfite and release carbon dioxide under pressure for use in the pressure carbonation. A portion of the sodium sulfite formed by decarbonation is then reduced in the smelter. The balance of the sodium sulfite is then used for absorption of the sulfur dioxide from the flue gas forming the sodium bisulfite used for decarbonation.

  8. The influence of pH on the oxygen isotope equilibrium fractionation between sulfite and water

    NASA Astrophysics Data System (ADS)

    Müller, Inigo; Brunner, Benjamin; Ferdelman, Timothy

    2010-05-01

    Currently, the value for the oxygen isotope equilibrium fractionation between water and sulfite in solution is poorly constrained. Sulfite is an important intermediate in the oxidative/reductive sulfur cycle and oxygen isotope exchange between sulfite and water is expected to leave an imprint on the isotope composition of sulfate affected by sulfur cycling. One reason for the lack of accurate information about isotope fractionation between sulfite and water are technical difficulties in extraction of sulfite from solution for oxygen isotope analysis. The pH dependent presence of multiple S(IV) species in solution, i.e. sulfur dioxide (SO2), bisulfite (HSO3-), pyrosulfite (S2O52-) and sulfite (SO32-) complicates data interpretation. For example, the oxygen isotope equilibrium fractionation between water and SO32- may be different than that between water and any of the other sulfite species in solution. We exposed sodium sulfite (Na2SO3) solutions to different pH conditions and monitored oxygen isotope exchange between sulfite and water, until isotope equilibrium was reached. The equilibrium value is determined by using two isotopically different sodium sulfite starting materials, one with a starting value lighter than the equilibrium value and one with a starting composition heavier than the equilibrium value. In this manner oxygen isotope equilibrium is approached from two directions. Sulfite from solution was precipitated as BaSO3 with a set of Ba(OH)2 solutions containing different oxygen isotope compositions. This procedure allows us to disentangle the oxygen isotope contribution from water incorporated during the precipitation from the oxygen isotope composition of sulfite in solution. We present the first results from this experimental approach and discuss the applicability of determining isotope equilibrium fractionations between water and distinct S(IV) species.

  9. Sulfites--a food and drug administration review of recalls and reported adverse events.

    PubMed

    Timbo, Babgaleh; Koehler, Kathleen M; Wolyniak, Cecilia; Klontz, Karl C

    2004-08-01

    Sulfite-sensitive individuals can experience adverse reactions after consuming foods containing sulfiting agents (sulfites), and some of these reactions may be severe. In the 1980s and 1990s, the U.S. Food and Drug Administration (FDA) acted to reduce the likelihood that sulfite-sensitive individuals would unknowingly consume foods containing sulfites. The FDA prohibited the use of sulfites on fruits and vegetables (except potatoes) to be served or presented fresh to the public and required that the presence of detectable levels of sulfites be declared on food labels, even when these sulfites are used as a processing aid or are a component of another ingredient in the food. In the present study, data from FDA recall records and adverse event reports were used to examine the current status of problems of sensitivity to sulfites in foods. From 1996 through 1999, the FDA processed a total of 59 recalls of foods containing undeclared sulfites; these 59 recalls involved 93 different food products. Fifty (55%) of the recalled products were classified as class I, a designation indicating that a consumer reasonably could have ingested > or = 10 mg of undeclared sulfites on a single occasion, a level that could potentially cause a serious adverse reaction in a susceptible person. From 1996 through mid-1999, the FDA received a total of 34 reports of adverse reactions allegedly due to eating foods containing undeclared sulfites. The average of 10 reports per year, although derived from a passive surveillance system, was lower than the average of 111 reports per year that the FDA received from 1980 to 1987, a decrease that may have resulted in part from FDA regulatory action.

  10. Molecular cloning and functional characterization of a putative sulfite oxidase (SO) ortholog from Nicotiana benthamiana.

    PubMed

    Xia, Zongliang; Su, Xinhong; Wu, Jianyu; Wu, Ke; Zhang, Hua

    2012-03-01

    Sulfite oxidase (SO) catalyzes the oxidation of sulfite to sulfate and thus has important roles in diverse metabolic processes. However, systematic molecular and functional investigations on the putative SO from tobacco (Nicotiana benthamiana) have hitherto not been reported. In this work, a full-length cDNA encoding putative sulfite oxidase from N. benthamiana (NbSO) was isolated. The deduced NbSO protein shares high homology and typical structural features with other species SOs. Phylogenetic analysis indicates that NbSO cDNA clone encodes a tobacco SO isoform. Southern blot analysis suggests that NbSO is a single-copy gene in the N. benthamiana genome. The NbSO transcript levels were higher in aerial tissues and were up-regulated in N. benthamiana during sulfite stress. Reducing the SO expression levels through virus-induced gene silencing caused a substantial accumulation in sulfite content and less sulfate accumulation in N. benthamiana leaves when exposed to sulfite stress, and thus resulted in decreased tolerance to sulfite stress. Taken together, this study improves our understanding on the molecular and functional properties of plant SO and provides genetic evidence on the involvement of SO in sulfite detoxification in a sulfite-oxidizing manner in N. benthamiana plants. PMID:21667106

  11. A boron-dipyrromethene-based fluorescent probe for colorimetric and ratiometric detection of sulfite.

    PubMed

    Gu, Xianfeng; Liu, Chunhua; Zhu, Yi-Chun; Zhu, Yi-Zhun

    2011-11-23

    BODIPY-Le, a colorimetric and ratiometric fluorescent probe based on boron-dipyrromethene for selective detection sulfite ion, was investigated. Boron-dipyrromethene levulinyl ester (BODIPY-Le) is composed of an indole-based BODIPY dye and the levulinyl protective group, which could be easily and selectively deprotected by sulfites. As a result, the absorption and emission spectra show a dramatic red shift, and the development of a colorimetric and ratiometric fluorescent sulfite probe could be achieved. Besides, BODIPY-Le also exhibited prominent turn-on or turn-off type fluorogenic signaling toward sulfite ions once excited at 510 and 620 nm, respectively.

  12. Catalytic oxidation of aqueous hydrogen sulfide in the presence of sulfite

    SciTech Connect

    Weres, O.; Tsao, L.; Chhatre, R.M.

    1985-06-01

    Nickel sulfate catalyzes the reaction of hydrogen sulfide with oxygen in aqueous solution. This reaction was studied, and an empirical rate expression and a reaction mechanism were deduced. The rate of oxidation is independent of oxygen concentration and pH over the range investigated. The reaction rate is one half order in nickel, and it changes from second to first order in sulfide with increasing concentration. The oxidation reaction is an autocatalytic, free radical chain reaction. Nickel catalyzes the chain initiation step, and polysulfido radical ions propagate the chains. Colloidal sulfur is a major, frequently undesirable reaction product. Sodium sulfite suppresses formation of colloidal sulfur by converting it to thiosulfate. Cobalt is an equally potent catalyst, but a colloidal dispersion of cobalt oxysulfide is produced. Iron compounds are much weaker catalysts; iron citrate and iron HEDTA (n-hydroxyethylenediaminetriacetic acid) were among those tested. 24 references, 15 figures, 3 tables.

  13. Influence of soil pH and application rate on the oxidation of calcium sulfite derived from flue gas desulfurization

    SciTech Connect

    Lee, Y.B.; Bigham, J.M.; Dick, W.A.; Jones, E.S.; Ramsier, C.

    2007-01-15

    Calcium sulfite hemihydrate (CaSO{sub 3} {center_dot} 0.5H{sub 2}O), a common byproduct of coal-fired utilities, is fairly insoluble and can decompose to release toxic SO{sub 2} under highly acidic soil conditions; however, it can also oxidize to form gypsum. The objective of this study was to examine the effects of application rate and soil pH on the oxidation of calcium sulfite under laboratory conditions. Oxidation rates measured by release of SO{sub 4}-S to solution decreased with increasing application rate. Leachate SO{sub 4}-S from soils amended with 1.0 to 3.0 g kg{sup -1} CaSO{sub 3} increased over a 21 to 28 d period before reaching a plateau. At 4 g kg{sup -1}, maximum SO{sub 4}-S release was delayed until Week 7. Oxidation and release of SO{sub 4}-S from soil amended with 3.0 g kg{sup -1} calcium sulfite increased markedly with decreasing soil pH. After only 3 d incubation, the concentrations of SO{sub 4}-S in aqueous leachates were 77, 122, 1709 220, and 229 mg L{sup -1} for initial soil pH values of 7.8, 6.5, 5.5, 5.1, and 4.0, respectively. At an initial soil pH value of 4.0, oxidation/dissolution did not increase much after 3 d. At higher pH values, oxidation was maximized after 21 d. These results suggest that autumn surface applications of calcium sulfite in no-till systems should permit ample time for oxidation/dissolution reactions to occur without introducing biocidal effects related to oxygen scavenging. Soil and annual crops can thus benefit from additions of soluble Ca and SO{sub 4} if calcium sulfite is applied in advance of spring planting.

  14. Disturbance of brain energy and redox homeostasis provoked by sulfite and thiosulfate: potential pathomechanisms involved in the neuropathology of sulfite oxidase deficiency.

    PubMed

    Grings, Mateus; Moura, Alana Pimentel; Parmeggiani, Belisa; Marcowich, Gustavo Flora; Amaral, Alexandre Umpierrez; de Souza Wyse, Angela Terezinha; Wajner, Moacir; Leipnitz, Guilhian

    2013-12-01

    Sulfite oxidase (SO) deficiency is biochemically characterized by tissue accumulation and high urinary excretion of sulfite, thiosulfate and S-sulfocysteine. Affected patients present severe neurological symptoms and cortical atrophy, whose pathophysiology is still poorly established. Therefore, in the present work we investigated the in vitro effects of sulfite and thiosulfate on important parameters of energy metabolism in the brain of young rats. We verified that sulfite moderately inhibited the activity of complex IV, whereas thiosulfate did not alter any of the activities of the respiratory chain complexes. It was also found that sulfite and thiosulfate markedly reduced the activity of total creatine kinase (CK) and its mitochondrial and cytosolic isoforms, suggesting that these metabolites impair brain cellular energy buffering and transfer. In contrast, the activity of synaptic Na(+),K(+)-ATPase was not altered by sulfite or thiosulfate. We also observed that the inhibitory effect of sulfite and thiosulfate on CK activity was prevented by melatonin, reduced glutathione and the combination of both antioxidants, as well as by the nitric oxide synthase N(ω)-nitro-l-arginine methyl ester, indicating the involvement of reactive oxygen and nitrogen species in these effects. Sulfite and thiosulfate also increased 2',7'-dichlorofluorescin oxidation and hydrogen peroxide production and decreased the activity of the redox sensor aconitase enzyme, reinforcing a role for oxidative damage in the effects elicited by these metabolites. It may be presumed that the disturbance of cellular energy and redox homeostasis provoked by sulfite and thiosulfate contributes to the neurological symptoms and abnormalities found in patients affected by SO deficiency.

  15. New insights into an ancient antibrowning agent: formation of sulfophenolics in sodium hydrogen sulfite-treated potato extracts.

    PubMed

    Narváez-Cuenca, Carlos-Eduardo; Kuijpers, Tomas F M; Vincken, Jean-Paul; de Waard, Pieter; Gruppen, Harry

    2011-09-28

    The effect of sodium hydrogen sulfite (S), used as antibrowning agent, on the phenolic profile of potato extracts was investigated. This extract was compared to one obtained in the presence of ascorbic acid (A). In the presence of A, two major compounds were obtained, 5-O-caffeoylquinic acid (5-CQA) and 4-O-caffeoyl quinic acid. With S, their 2'-sulfo-adducts were found instead, the structures of which were confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. Also, for minor caffeoyl derivatives and quercetin glycosides, the corresponding sulfo-adducts were observed. Feruloyl and sinapoyl derivatives were not chemically affected by the presence of S. Polyphenol oxidase (PPO) was thought to be responsible for the formation of the sulfo-adducts. This was confirmed by preparing 2'-sulfo-5-O-caffeoyl quinic acid in a model system using 5-CQA, sodium hydrogen sulfite, and PPO. This sulfo-adduct exhibited a small bathochromic shift (λmax 329 nm) as compared to 5-CQA (λmax 325 nm) and a strong hypochromic shift with an extinction coefficient of 9357±395 M(-1) cm(-1) as compared to 18494±196 M(-1) cm(-1), respectively. The results suggest that whenever S is used as an antibrowning agent, the O-quinone formed with PPO reacts with S to produce sulfo-O-diphenol, which does not participate in browning reactions. PMID:21854040

  16. Purification and characterization of ferredoxin-sulfite reductase from turnip (Brassica rapa) leaves and comparison of properties with ferredoxin-sulfite reductase from turnip roots.

    PubMed

    Takahashi, S; Yip, W C; Tamura, G

    1997-09-01

    Ferredoxin-sulfite reductase (Fd-SiR) [hydrogen-sulfide: ferredoxin oxidoreductase, EC 1.8.7.1] from turnip leaves (SiR-L) has been purified to homogeneity and its enzymatic properties compared with that from turnip roots (SiR-R). Each enzyme had a molecular mass of 64.5 +/- 0.5 kDa by SDS-PAGE and an isoelectric point of 5.15 +/- 0.05. Although each had a pH optimum around 7.8 with the same effects of inhibitors, SiR-L had higher heat stability at 60 degrees C than SiR-R. Moreover, SiR-R had a lower K(m) and a higher specificity constant (kcat/K(m)) for turnip leaf ferredoxin than SiR-L. The N-terminal amino acid sequence of SiR-L was different from that of SiR-R. The results of amino acid analysis and peptide mapping suggested that SiR-L and SiR-R have different primary structures.

  17. 21 CFR 201.22 - Prescription drugs containing sulfites; required warning statements.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... demonstrated that sulfites may cause allergic-type reactions in certain susceptible persons, especially... metabisulfite), a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life... products cause allergic-type reactions including anaphylactic symptoms or life-threatening or less...

  18. 21 CFR 201.22 - Prescription drugs containing sulfites; required warning statements.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... demonstrated that sulfites may cause allergic-type reactions in certain susceptible persons, especially... metabisulfite), a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life... products cause allergic-type reactions including anaphylactic symptoms or life-threatening or less...

  19. 21 CFR 201.22 - Prescription drugs containing sulfites; required warning statements.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... demonstrated that sulfites may cause allergic-type reactions in certain susceptible persons, especially... metabisulfite), a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life... products cause allergic-type reactions including anaphylactic symptoms or life-threatening or less...

  20. 21 CFR 201.22 - Prescription drugs containing sulfites; required warning statements.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... demonstrated that sulfites may cause allergic-type reactions in certain susceptible persons, especially... metabisulfite), a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life... products cause allergic-type reactions including anaphylactic symptoms or life-threatening or less...

  1. 40 CFR 430.50 - Applicability; description of the papergrade sulfite subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) THE PULP, PAPER, AND PAPERBOARD POINT... production of pulp and paper at papergrade sulfite mills, where blow pit pulp washing techniques are used; and the integrated production of pulp and paper at papergrade sulfite mills where vacuum or...

  2. 40 CFR 430.50 - Applicability; description of the papergrade sulfite subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) THE PULP, PAPER, AND PAPERBOARD POINT... production of pulp and paper at papergrade sulfite mills, where blow pit pulp washing techniques are used; and the integrated production of pulp and paper at papergrade sulfite mills where vacuum or...

  3. 40 CFR 430.50 - Applicability; description of the papergrade sulfite subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE... pulp and paper at papergrade sulfite mills, where blow pit pulp washing techniques are used; and the integrated production of pulp and paper at papergrade sulfite mills where vacuum or pressure drums are...

  4. 40 CFR 430.50 - Applicability; description of the papergrade sulfite subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) THE PULP, PAPER, AND PAPERBOARD POINT... production of pulp and paper at papergrade sulfite mills, where blow pit pulp washing techniques are used; and the integrated production of pulp and paper at papergrade sulfite mills where vacuum or...

  5. 40 CFR 430.50 - Applicability; description of the papergrade sulfite subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE... pulp and paper at papergrade sulfite mills, where blow pit pulp washing techniques are used; and the integrated production of pulp and paper at papergrade sulfite mills where vacuum or pressure drums are...

  6. 40 CFR 415.200 - Applicability; description of the sodium sulfite production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the sodium sulfite production subcategory. 415.200 Section 415.200 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Sodium Sulfite...

  7. Spectrophotometric Determination of Total Sulfite in White Wine Samples Using Crude Extracts from Flowers

    NASA Astrophysics Data System (ADS)

    Flora Barbosa Soares, Márlon Herbert; Ramos, Luiz Antonio; Tadeu Gomes Cavalheiro, Éder

    2002-09-01

    A didactic spectrophotometric method for determining the sulfite content in white wine samples is proposed. It is based upon a discoloring reaction between flower anthocyanins and the sulfite in basic media. Students' results obtained from iodometric data agreed well with results obtained by the proposed procedure. The use of natural dyes attracted students' interest, enhancing the learning process.

  8. A new diketopyrrolopyrrole-based probe for sensitive and selective detection of sulfite in aqueous solution

    NASA Astrophysics Data System (ADS)

    Yang, Xiaofeng; Cui, Yu; Li, Yexin; Zheng, Luyi; Xie, Lijun; Ning, Rui; Liu, Zheng; Lu, Junling; Zhang, Gege; Liu, Chunxiang; Zhang, Guangyou

    2015-02-01

    A new probe was synthesized by incorporating an α,β -unsaturated ketone to a diketopyrrolopyrrole fluorophore. The probe had exhibited a selective and sensitive response to the sulfite against other thirteen anions and biothiols (Cys, Hcy and GSH), through the nucleophilic addition of sulfite to the alkene of probe with the detection limit of 0.1 μM in HEPES (10 mM, pH 7.4) THF/H2O (1:1, v/v). Meanwhile, it could be easily observed that the probe for sulfite changed from pink to colorless by the naked eye, and from pink to blue under UV lamp after the sulfite was added for 20 min. The NMR and Mass spectral analysis demonstrated the expected addition of sulfite to the Cdbnd C bonds.

  9. Structural basis of interprotein electron transfer in bacterial sulfite oxidation

    PubMed Central

    McGrath, Aaron P; Laming, Elise L; Casas Garcia, G Patricia; Kvansakul, Marc; Guss, J Mitchell; Trewhella, Jill; Calmes, Benoit; Bernhardt, Paul V; Kappler, Ulrike; Maher, Megan J

    2015-01-01

    Interprotein electron transfer underpins the essential processes of life and relies on the formation of specific, yet transient protein-protein interactions. In biological systems, the detoxification of sulfite is catalyzed by the sulfite-oxidizing enzymes (SOEs), which interact with an electron acceptor for catalytic turnover. Here, we report the structural and functional analyses of the SOE SorT from Sinorhizobium meliloti and its cognate electron acceptor SorU. Kinetic and thermodynamic analyses of the SorT/SorU interaction show the complex is dynamic in solution, and that the proteins interact with Kd = 13.5 ± 0.8 μM. The crystal structures of the oxidized SorT and SorU, both in isolation and in complex, reveal the interface to be remarkably electrostatic, with an unusually large number of direct hydrogen bonding interactions. The assembly of the complex is accompanied by an adjustment in the structure of SorU, and conformational sampling provides a mechanism for dissociation of the SorT/SorU assembly. DOI: http://dx.doi.org/10.7554/eLife.09066.001 PMID:26687009

  10. Removal of sulfide, sulfate and sulfite ions by electro coagulation.

    PubMed

    Murugananthan, M; Raju, G Bhaskar; Prabhakar, S

    2004-06-18

    The removal of various species of sulfur from beamhouse of tannery wastewater and also from synthetic samples was studied by electro-flotation technique. Consumable anodes of iron and aluminum and insoluble anode of titanium were tested as anodes. It was found that iron and aluminum anodes were effective for the removal of suspended solids, sulfide, sulfite and sulfate. Progress of simultaneous coagulation of suspended solids during electro-flotation was measured using particle size analysis. Coagulation was found to be essential for effective flotation of suspended solids. Metal ions generated in situ by electrolytic oxidation of anode were found to react with dissolved sulfide ions. Metal sulfides thus formed as colloidal suspension were coagulated and floated simultaneously by hydrogen bubbles generated from cathode. Simultaneous occurrence of precipitation, coagulation and flotation was observed during electro-flotation. X-ray diffraction studies were conducted to identify the nature of sulfide phase formed during electrolytic precipitation. The effect of pH, current density and initial concentration of pollutants was studied and the results are discussed. The removal of sulfite and sulfate ions is explained by zeta-potential measurements. PMID:15177743

  11. Oxidative Half-reaction of Arabidopsis thaliana Sulfite Oxidase

    PubMed Central

    Byrne, Robert S.; Hänsch, Robert; Mendel, Ralf R.; Hille, Russ

    2009-01-01

    Vertebrate forms of the molybdenum-containing enzyme sulfite oxidase possess a b-type cytochrome prosthetic group that accepts reducing equivalents from the molybdenum center and passes them on to cytochrome c. The plant form of the enzyme, on the other hand, lacks a prosthetic group other than its molybdenum center and utilizes molecular oxygen as the physiological oxidant. Hydrogen peroxide is the ultimate product of the reaction. Here, we present data demonstrating that superoxide is produced essentially quantitatively both in the course of the reaction of reduced enzyme with O2 and during steady-state turnover and only subsequently decays (presumably noncatalytically) to form hydrogen peroxide. Rapid-reaction kinetic studies directly following the reoxidation of reduced enzyme demonstrate a linear dependence of the rate constant for the reaction on [O2] with a second-order rate constant of kox = 8.7 × 104 ± 0.5 × 104 m−1s−1. When the reaction is carried out in the presence of cytochrome c to follow superoxide generation, biphasic time courses are observed, indicating that a first equivalent of superoxide is generated in the oxidation of the fully reduced Mo(IV) state of the enzyme to Mo(V), followed by a slower oxidation of the Mo(V) state to Mo(VI). The physiological implications of plant sulfite oxidase as a copious generator of superoxide are discussed. PMID:19875441

  12. Removal of sulfide, sulfate and sulfite ions by electro coagulation.

    PubMed

    Murugananthan, M; Raju, G Bhaskar; Prabhakar, S

    2004-06-18

    The removal of various species of sulfur from beamhouse of tannery wastewater and also from synthetic samples was studied by electro-flotation technique. Consumable anodes of iron and aluminum and insoluble anode of titanium were tested as anodes. It was found that iron and aluminum anodes were effective for the removal of suspended solids, sulfide, sulfite and sulfate. Progress of simultaneous coagulation of suspended solids during electro-flotation was measured using particle size analysis. Coagulation was found to be essential for effective flotation of suspended solids. Metal ions generated in situ by electrolytic oxidation of anode were found to react with dissolved sulfide ions. Metal sulfides thus formed as colloidal suspension were coagulated and floated simultaneously by hydrogen bubbles generated from cathode. Simultaneous occurrence of precipitation, coagulation and flotation was observed during electro-flotation. X-ray diffraction studies were conducted to identify the nature of sulfide phase formed during electrolytic precipitation. The effect of pH, current density and initial concentration of pollutants was studied and the results are discussed. The removal of sulfite and sulfate ions is explained by zeta-potential measurements.

  13. Structural basis of interprotein electron transfer in bacterial sulfite oxidation.

    PubMed

    McGrath, Aaron P; Laming, Elise L; Casas Garcia, G Patricia; Kvansakul, Marc; Guss, J Mitchell; Trewhella, Jill; Calmes, Benoit; Bernhardt, Paul V; Hanson, Graeme R; Kappler, Ulrike; Maher, Megan J

    2015-12-19

    Interprotein electron transfer underpins the essential processes of life and relies on the formation of specific, yet transient protein-protein interactions. In biological systems, the detoxification of sulfite is catalyzed by the sulfite-oxidizing enzymes (SOEs), which interact with an electron acceptor for catalytic turnover. Here, we report the structural and functional analyses of the SOE SorT from Sinorhizobium meliloti and its cognate electron acceptor SorU. Kinetic and thermodynamic analyses of the SorT/SorU interaction show the complex is dynamic in solution, and that the proteins interact with Kd = 13.5 ± 0.8 μM. The crystal structures of the oxidized SorT and SorU, both in isolation and in complex, reveal the interface to be remarkably electrostatic, with an unusually large number of direct hydrogen bonding interactions. The assembly of the complex is accompanied by an adjustment in the structure of SorU, and conformational sampling provides a mechanism for dissociation of the SorT/SorU assembly.

  14. Effects of Interdomain-Tether Length and Flexibility on the Kinetics of Intramolecular Electron Transfer in Human Sulfite Oxidas†

    PubMed Central

    Johnson-Winters, Kayunta; Nordstrom, Anna R.; Emesh, Safia; Astashkin, Andrei V.; Rajapakshe, Asha; Berry, Robert; Tollin, Gordon; Enemark, John H.

    2010-01-01

    Sulfite oxidase (SO) is a vitally important molybdenum enzyme that catalyzes the oxidation of toxic sulfite to sulfate. The proposed catalytic mechanism of vertebrate SO involves two intramolecular one-electron transfer (IET) steps from the molybdenum cofactor to the iron of the integral b-type heme and two intermolecular one-electron steps to exogenous cytochrome c. In the crystal structure of chicken SO (Kisker et al., Cell, 1997, 91, 973–983), which is highly homologous to human SO (HSO), the heme iron and molybdenum centers are separated by 32 Å, and the domains containing these centers are linked by a flexible polypeptide tether. Conformational changes that bring these two centers into closer proximity have been proposed (Feng et al., Biochemistry, 2003, 41, 5816–21) to explain the relatively rapid IET kinetics, which are much faster than theoretically predicted from the crystal structure. In order to explore the proposed role(s) of the tether in facilitating this conformational change, both its length and flexibility were altered in HSO by site-specific mutagenesis and the reactivities of the resulting variants have been studied using laser flash photolysis and steady-state kinetics assays. Increasing the flexibility of the tether by mutating several conserved proline residues to alanines did not produce a discernable systematic trend in the kinetic parameters, although mutation of one residue (P105) to alanine produced a three-fold decrease in the IET rate constant. Deletions of non-conserved amino acids in the 14-residue tether, thereby shortening its length, resulted in more drastically reduced IET rate constants. Thus, the deletion of five amino acid residues decreased IET by 70-fold, so that it was rate-limiting in the overall reaction. The steady-state kinetic parameters were also significantly affected by these mutations, with the P111A mutation causing a five-fold increase in the sulfite Km value, perhaps reflecting a decrease in the ability to

  15. Desulfoviridin, a multimeric-dissimilatory sulfite reductase from Desulfovibrio vulgaris (Hildenborough). Purification, characterization, kinetics and EPR studies.

    PubMed

    Wolfe, B M; Lui, S M; Cowan, J A

    1994-07-01

    Conditions for the rigorous purification of desulfoviridin, the dissimilatory sulfite reductase from the sulfate-reducing bacterium Desulfovibrio vulgaris (Hildenborough) have been established. A final purification by fast protein liquid chromatography yields at least three distinct bands that each exhibit the characteristic absorption spectrum of desulfoviridin. Two of these have been extensively characterized by amino acid analysis, isoelectric focusing, polyacrylamide gel electrophoresis, and formulation of the prosthetic centers. Each contains two pairs of [Fe4S4] and siroheme units. These results stand in marked contrast to recent work claiming significant demetallation of siroheme, excess iron content, and the presence of Fe6S6 clusters. These proposals are critically assessed in light of our results and other published work. Steady-state kinetic parameters have been determined: kcat(SO3(2-) = 0.31 mol SO3(2-).s-1.mol heme-1, Km = 0.06 mM; kcat(NO2-) = 0.038 mol NO2-.s-1.mol heme-1, Km = 0.028 mM; kcat(NH2OH) = 29 mol NH2OH.s-1.mol heme-1, Km = 48 mM. A detailed comparison is made with the Escherichia coli and spinach assimilatory sulfite reductase enzymes and spinach nitrite reductase. Highly purified samples of dissimilatory sulfite reductase display an electron paramagnetic resonance spectrum characteristic of rhombic high spin ferric heme centers, while the fully reduced enzyme shows EPR features typical of [Fe4S4] clusters. The magnetic properties of the prosthetic centers are further characterized by variable temperature experiments and spin quantitation.

  16. The kinetic behavior of chicken liver sulfite oxidase.

    PubMed

    Brody, M S; Hille, R

    1999-05-18

    A comprehensive kinetic study of sulfite oxidase has been undertaken over the pH range 6.0-10.0, including conventional steady-state work as well as rapid kinetic studies of both the reaction of oxidized enzyme with sulfite and reduced enzyme with cytochrome c (III). A comparison of the pH dependence of kcat, kred, and kox indicates that kred is principally rate limiting above pH 7, but that below this pH the pH dependence of kcat is influenced by that of kox. The pH independence of kred is consistent with our previous proposal concerning the reaction mechanism, in which attack of the substrate lone pair of electrons on a Mo(VI)O2 unit initiates the catalytic sequence. The pH dependence of kred/Kdsulfite indicates that a group on the enzyme having a pKa of approximately 9.3 must be deprotonated for effective reaction of oxidized enzyme with sulfite, possibly Tyr 322, which from the crystal structure of the enzyme constitutes part of the substrate binding site. There is no evidence for the HSO3-/SO32- pKa of approximately 7 in the pH profile for kred/Kdsulfite, suggesting that enzyme is able to oxidize the two equally well. By contrast, kcat/Kmsulfite and kred/Kdsulfite exhibit distinct pH dependence (the former is bell-shaped, the latter sigmoidal), again consistent with the oxidative half-reaction contributing to the kinetic barrier to catalysis at low pH. The pH dependence of kcat/Km(cyt c) (reflecting the second-order rate of reaction of free enzyme with free cytochrome) is bell-shaped and closely resembles that of kox/Kd(cyt c), reflecting the importance of the oxidative half-reaction in the low substrate concentration regime. The pH profile for kox/Kd(cyt c) indicates that two groups with a pKa of approximately 8 are involved in the reaction of free reduced enzyme with cytochrome c, one of which must be deprotonated and the other protonated. These results are consistent with the known electrostatic nature of the interaction of cytochrome c with its

  17. Stability of apigeninidin and its methoxylated derivatives in the presence of sulfites.

    PubMed

    Ojwang, Leonnard O; Awika, Joseph M

    2010-08-25

    3-Deoxyanthocyanin pigments are more stable than anthocyanins and show promising bioactive properties. However, little is known about their stability in the presence of food additives such as sulfites. This work investigates the stability of apigeninidin and its derivatives in the presence of sulfites. Pigment (apigeninidin, 5-mono-, and 5,7-dimethoxyapigeninidin) stability at pH 1.8, 3.0, and 5.0, in the presence of sodium metabisulfite (molar ratio ∼ 1:40, pigment/SO2) was monitored over 21 days at room temperature. The structure of sulfite complexation products was monitored using HPLC-MS and NMR spectroscopy. All pigments were significantly bleached within 30 min in the presence of sulfites; the bleaching effect was more severe at pH 5.0 and 3.0 compared to pH 1.8. Apigeninidin was more resistant to bleaching than its methoxylated derivatives. However, all pigments regained some or all of the bleached color within 14-21 days at pH 3.0 and 1.8 in the presence of sulfites, indicating equilibrium favored flavylium cation at these pH values. Formation of colorless sulfonates via bisulfite ion addition at C-4 was responsible for the bleaching effect. Both structure and pH significantly affected stability of 3-deoxyanthocyanidins in the presence of sulfites. The pigments may have potential applications in low pH systems containing sulfites.

  18. Dispersion of optical activity of magnesium sulfite hexahydrate single crystals

    NASA Astrophysics Data System (ADS)

    Dimov, T.; Bunzarov, Zh; Iliev, I.; Petkova, P.; Tzoukrovski, Y.

    2010-11-01

    The magnesium sulfite hexahydrate (MgSO3.6H2O) crystals are unique because they are the only representative (with sodium periodate) of the crystallographic class C3 (without a center of symmetry). The crystal symmetry suggests presence of nonlinearity, piezo- and pyro-electric properties and gyrotropy as well. Single crystals of MgSO3.6H2O (pure and doped with Ni, Co and Zn) for the time being are grown only by the original method developed in the Laboratory for Crystal growth at the Faculty of Physics in Sofia University. The first results of optical activity of pure MgSO3.6H2O and Zn doped MgSO3.6H2O crystals are described and analyzed in a wide spectral range. The optical activity manifests itself in the direction (0001) as a rotation of the polarization plane.

  19. Isolation and characterization of sulfite oxidase from Alligator mississipiensis

    SciTech Connect

    Robbins, A.; Neame, P.J.; Barber, M.J. )

    1991-03-11

    Sulfite oxidase has been isolated from fresh alligator liver using ammonium sulfate and acetone fractionation, DEAE chromatography and FPLC on Mono Q. The enzyme is dimeric and exhibits a subunit M. Wt. of approximately 58 kDa, larger than that of chicken SO. EPR spectroscopy of the partially-reduced enzyme revealed a single Mo(V) species while visible spectroscopy revealed the presence of cytochrome b{sub 557}. Maximal activities were obtained at pH 8 and 9, respectively. K{sub m}'s for SO{sub 3}{sup 2 {minus}}, cyt. c and Fe(CN){sub 6}{sup 3 {minus}} were 23.5 uM, 2.9 uM and 8.0 uM, respectively. Sequencing of peptides obtained by endoprotease K digestion indicated regions of extensive sequence similarity to chicken and rat enzymes in both heme and Mo-pterin domains. Regions of sequence dissimilarity were also found.

  20. Sulfite determination by an inhibitor biosensor-based mushroom (Agaricus bisporus) tissue homogenate.

    PubMed

    Sezgintürk, Mustafa Kemal; Dinçkaya, Erhan

    2012-02-01

    The aim of the study presented here is to develop a biosensor based on mushroom (Agaricus bisporus) tissue homogenate for sensitive and economical determination of sulfite in foods. The working principle of the biosensor is based on an inhibition effect of sulfite on polyphenol oxidases in mushroom. Mushroom tissue homogenate was immobilized by gelatin and glutaraldehyde on a Clark-type oxygen electrode. Some optimization studies related to the bioactive layer components and working conditions were identified. The biosensor was applied to the food samples. The biosensor reported here was successfully allowed to analyze sulfite, which was a food additive in real food samples.

  1. Circular dichroism in magnesium sulfite hexahydrate doped with cobalt

    NASA Astrophysics Data System (ADS)

    Bunzarov, Zh.; Iliev, I.; Dimov, T.; Petkova, P.; Kovachev, Tz.; Lyutov, L.; Tzoukrovski, Y.

    2009-10-01

    The new nonlinear crystal of magnesium sulfite hexahydrate (MgSO3.6H2O) belongs to the rare crystallographic class C3 (without a symmetry centre), the other known only representative being sodium periodate (NaIO4). There are some scarce data in the scientific papers about magnesium sulfite hexahydrate's physical properties. Single crystals of significant sizes (up to 40-50 mm) of MgSO3.6H2O as well as such, doped with Ni, Co, and Zn, for the time being are grown only by our own method developed in the Laboratory for Crystal growth at the Faculty of Physics of Sofia University. Recently we have observed the supposed presence of optical activity. Circular dichroism is not observed in pure MgSO3.6H2O. The results of the first ever investigations are presented, which demonstrate the presence of circular dichroism in MgSO3.6H2O doped with Co. The circular dichroism appears in the spectral range from 420 nm to 580 nm. The spectrum of circular dichroism demonstrates a well expressed structure - an isolated maximum at 470 nm and a combination of two overlapped maxima at ~ 495 nm and 520 nm respectively. The spectrum of the circular dichroism is compared with the absorption spectrum of MgSO3.6H2O:Co, along the direction (0001) and with the linear dichroism spectrum measured in direction(1210). It is shown in this way that the circular dichroism appears only in the spectral range of the optical absorption structure due to Co dopant. In the same spectral range can be observed also the linear dichroism determined by Co presence in MgSO3.6H2O.

  2. Contribution of dissolved sulfates and sulfites in hydrogen sulfide emission from stagnant water bodies in Sri Lanka.

    PubMed

    Kularatne, K I A; Dissanayake, D P; Mahanama, K R R

    2003-08-01

    Accumulation of sulfur-containing compounds and their bacterial mediated reductions have led to the emission of pungent odors from stagnant water bodies. This study is focused on the contribution of inorganic sulfur compounds in the emission of hydrogen sulfide. The measured dissolved oxygen levels have demonstrated good negative correlations with the dissolved sulfide levels implying the oxygen deficiency is the key for the reduction of sulfate ion and sulfite ion to sulfide ion. Particularly, the dissolved molar fractions of sulfide from the total dissolved sulfur compounds (sulfates, sulfites and sulfides) have a very good correlation with the dissolved oxygen for the stagnant water bodies except the artificially aerated prawn farms. For the stagnant water bodies with significant correlations, linear regressions are reported for them to be utilized in estimating one component of the regression from the measurement of the other. The measured data were further utilized to estimate the levels of hydrogen sulfide gas. The pH of the water bodies has confined much of the dissolved sulfides in the form of bisulfide ion and they can be easily escaped to the atmosphere upon acidification due to industrial discharges and/or acidic precipitations. The estimated levels of hydrogen sulfide just above the water surface were plotted for the most polluted stagnant water body in Sri Lanka for the pH range of 5-10 and temperature range of 25-35 degrees C.

  3. Impairment in Sulfite Reductase Leads to Early Leaf Senescence in Tomato Plants1[W][OPEN

    PubMed Central

    Yarmolinsky, Dmitry; Brychkova, Galina; Kurmanbayeva, Assylay; Bekturova, Aizat; Ventura, Yvonne; Khozin-Goldberg, Inna; Eppel, Amir; Fluhr, Robert; Sagi, Moshe

    2014-01-01

    Sulfite reductase (SiR) is an essential enzyme of the sulfate assimilation reductive pathway, which catalyzes the reduction of sulfite to sulfide. Here, we show that tomato (Solanum lycopersicum) plants with impaired SiR expression due to RNA interference (SIR Ri) developed early leaf senescence. The visual chlorophyll degradation in leaves of SIR Ri mutants was accompanied by a reduction of maximal quantum yield, as well as accumulation of hydrogen peroxide and malondialdehyde, a product of lipid peroxidation. Interestingly, messenger RNA transcripts and proteins involved in chlorophyll breakdown in the chloroplasts were found to be enhanced in the mutants, while transcripts and their plastidic proteins, functioning in photosystem II, were reduced in these mutants compared with wild-type leaves. As a consequence of SiR impairment, the levels of sulfite, sulfate, and thiosulfate were higher and glutathione levels were lower compared with the wild type. Unexpectedly, in a futile attempt to compensate for the low glutathione, the activity of adenosine-5′-phosphosulfate reductase was enhanced, leading to further sulfite accumulation in SIR Ri plants. Increased sulfite oxidation to sulfate and incorporation of sulfite into sulfoquinovosyl diacylglycerols were not sufficient to maintain low basal sulfite levels, resulting in accumulative leaf damage in mutant leaves. Our results indicate that, in addition to its biosynthetic role, SiR plays an important role in prevention of premature senescence. The higher sulfite is likely the main reason for the initiation of chlorophyll degradation, while the lower glutathione as well as the higher hydrogen peroxide and malondialdehyde additionally contribute to premature senescence in mutant leaves. PMID:24987017

  4. Sulfite oxidase controls sulfur metabolism under SO2 exposure in Arabidopsis thaliana.

    PubMed

    Randewig, Dörte; Hamisch, Domenica; Herschbach, Cornelia; Eiblmeier, Monika; Gehl, Christian; Jurgeleit, Jens; Skerra, Jessica; Mendel, Ralf R; Rennenberg, Heinz; Hänsch, Robert

    2012-01-01

    In the present study, the significance of sulfite oxidase (SO) for sulfite detoxification and sulfur assimilation was investigated. In response to sulfur dioxide (SO(2)) exposure, a remarkable expansion of sulfate and a significant increase of GSH pool were observed in wild-type and SO-overexpressing Arabidopsis. These metabolic changes were connected with a negative feedback inhibition of adenosine 5'-phosphosulfate reductase (APR), but no alterations in gas exchange parameters or visible symptoms of injury. However, Arabidopsis SO-KO mutants were consistently negatively affected upon 600 nL L(-1) SO(2) exposure for 60 h and showed phenotypical symptoms of injury with small necrotic spots on the leaves. The mean g(H2O) was reduced by about 60% over the fumigation period, accompanied by a reduction of net CO(2) assimilation and SO(2) uptake of about 50 and 35%. Moreover, sulfur metabolism was completely distorted. Whereas sulfate pool was kept constant, thiol-levels strongly increased. This demonstrates that SO should be the only protagonist for back-oxidizing and detoxification of sulfite. Based on these results, it is suggested that co-regulation of SO and APR controls sulfate assimilation pathway and stabilizes sulfite distribution into organic sulfur compounds. In conclusion, a sulfate-sulfite cycle driven by APR and SO can be postulated for fine-tuning of sulfur distribution that is additionally used for sulfite detoxification, when plants are exposed to atmospheric SO(2). PMID:21895698

  5. Regioselective enzymatic acylations of polyhydroxylated eudesmanes: semisynthesis, theoretical calculations, and biotransformation of cyclic sulfites.

    PubMed

    García-Granados, A; Melguizo, E; Parra, A; Simeó, Y; Viseras, B; Dobado, J A; Molina, J; Arias, J M

    2000-12-01

    Different lipase enzymes have been tested in order to perform regioselective acetylations on the eudesmane tetrol from vulgarin. High yields (95%) of 1,12-diacetoxy derivative (4) were achieved in 1 h with Candida antarctica lipase (CAL). However, only the 12-acetyl derivative (6) was obtained in similar yield with Mucor miehei (MML) or Candida cylindracea (CCL) lipases. The enzymatic protection at C-1 and C-12 has been used to form eudesmane cyclic-sulfites between C-6 and C-4 atoms. The R/S-sulfur configuration has been assigned by means of the experimental and theoretical (13)C and (1)H NMR chemical shifts. The theoretical shifts were calculated using the GIAO method, with a MM+ geometry optimization followed by a single-point calculation at the B3LYP/6-31G(*) level (B3LYP/6-31G(*)//MM+). Moreover, B3LYP/6-31G(*) geometry optimizations were carried out to test the B3LYP/6-31G(*)//MM+ results, for the deacetylated sulfites (12 and 15). In addition to the delta(C) and delta(H) shifts, the (3)J(HH) coupling constants were also calculated and compared with the experimental values when available. Finally, different reactivities have been checked in both sulfites by biotransformation with Rhizopus nigricans. While the R-sulfite gave 2 alpha- and 11 beta-hydroxylated metabolites, the S-sulfite yielded only regioselective deacetylations. Furthermore, both sulfites showed different reactivities in redox processes.

  6. The Structures of the C185S and C185A Mutants of Sulfite Oxidase Reveal Rearrangement of the Active Site

    SciTech Connect

    Qiu, James A.; Wilson, Heather L.; Pushie, M. Jake; Kisker, Caroline; George, Graham N.; Rajagopalan, K.V.

    2010-11-03

    Sulfite oxidase (SO) catalyzes the physiologically critical conversion of sulfite to sulfate. Enzymatic activity is dependent on the presence of the metal molybdenum complexed with a pyranopterin-dithiolene cofactor termed molybdopterin. Comparison of the amino acid sequences of SOs from a variety of sources has identified a single conserved Cys residue essential for catalytic activity. The crystal structure of chicken liver sulfite oxidase indicated that this residue, Cys185 in chicken SO, coordinates the Mo atom in the active site. To improve our understanding of the role of this residue in the catalytic mechanism of sulfite oxidase, serine and alanine variants at position 185 of recombinant chicken SO were generated. Spectroscopic and kinetic studies indicate that neither variant is capable of sulfite oxidation. The crystal structure of the C185S variant was determined to 1.9 {angstrom} resolution and to 2.4 {angstrom} resolution in the presence of sulfite, and the C185A variant to 2.8 {angstrom} resolution. The structures of the C185S and C185A variants revealed that neither the Ser or Ala side chains appeared to closely interact with the Mo atom and that a third oxo group replaced the usual cysteine sulfur ligand at the Mo center, confirming earlier extended X-ray absorption fine structure spectroscopy (EXAFS) work on the human C207S mutant. An unexpected result was that in the C185S variant, in the absence of sulfite, the active site residue Tyr322 became disordered as did the loop region flanking it. In the C185S variant crystallized in the presence of sulfite, the Tyr322 residue relocalized to the active site. The C185A variant structure also indicated the presence of a third oxygen ligand; however, Tyr322 remained in the active site. EXAFS studies of the Mo coordination environment indicate the Mo atom is in the oxidized Mo{sup VI} state in both the C185S and C185A variants of chicken SO and show the expected trioxodithiolene active site. Density

  7. Electrochemical titrations of thiosulfate, sulfite, dichromate and permanganate using dual microband electrodes.

    PubMed

    Rajantie, H; Williams, D E

    2001-01-01

    Applications of titration using dual gold microband electrodes in generator-collector mode are presented. The main advantage is that the method dispenses with the need for accurate volume measurements and reagent preparation: rather than balancing of molar amounts, the fluxes of analyte and titrant are balanced instead. The titrant is generated electrochemically and the end-point is detected amperometrically by the appearance of a current due to the presence of the titrant at the other band. The aim is to show the versatility and capability of the method that employs disposable mass-produced electrodes and uses pulsed motion of the electrode before a measurement to renew the boundary conditions. The titration of ascorbic acid (vitamin C) with ferricyanide, which has been a model system, was extended to the determination of thiosulfate and sulfite with iodine and the determination of dichromate and permanganate with iron(II). The accuracy, limited by the present fabrication reproducibility of the disposable electrodes, is +/- 10%. The results demonstrate that the method is effective even with a very simple set-up, and the actual time needed for common titrations is significantly decreased. These examples demonstrate a comprehensive basis for further development and applications, including standard titrations in industry.

  8. Molecular characterization of tobacco sulfite reductase: enzyme purification, gene cloning, and gene expression analysis.

    PubMed

    Yonekura-Sakakibara, K; Ashikari, T; Tanaka, Y; Kusumi, T a; Hase, T

    1998-09-01

    A cDNA clone, NtSiR1, that encodes the precursor of ferredoxin-dependent sulfite reductase (Fd-SiR) has been isolated from a cDNA library of tobacco (Nicotiana tabacum cv. SR1). The identity of the cDNA was established by comparison of the purified protein and the predicted structure with the nucleotide sequence. The amino terminus of the purified enzyme was Thr62 of the precursor protein, and the mature region of NtSiR1 consisted of 632 amino acids. Tobacco Fd-SiR is 82, 77, and 48% identical with Fd-SiRs from Zea mays, Arabidopsis thaliana, and a cyanobacterium, respectively. Significant similarity was also found with Escherichia coli NADPH-SiR in the region involved in ligation of siroheme and the [4Fe-4S] cluster. On Northern blot analysis, a transcript of NtSiR1 was detected in leaves, stems, roots, and petals in similar amounts. We also isolated a genomic SiR clone named gNtSiR1. It consists of 8 exons and 7 introns. Genomic Southern blot analysis indicated that at least two SiR genes are present in the tobacco genome. PMID:9722674

  9. Effect of gel network on pattern formation in the ferrocyanide-iodate-sulfite reaction.

    PubMed

    Ueno, Tomonaga; Yoshida, Ryo

    2011-06-01

    Stationary patterns have been researched experimentally since the discovery of the Turing pattern in the chlorite-iodide-malonic acid (CIMA) reaction and the self-replicating spot pattern in the ferrocyanide-iodate-sulfite (FIS) reaction. In this study, we reproduced the pattern formation in the FIS reaction by using poly(acrylamide) gels. Gels with different swelling ratios were prepared to use as a medium. The effect of the swelling ratio was compared with the effect of thickness. It was found that the swelling ratio greatly influenced pattern formation. Oscillating spot patterns appeared at high swelling ratios, and lamellar patterns appeared at a low swelling ratio. Self-replicating spot patterns appeared in between the two areas. The front velocities, which were observed in the initial stage of pattern formation, depended on the swelling ratio. Furthermore, this dependence obeys the free volume theory of diffusion. These results provide evidence that the change in front velocities is caused by a change in diffusion. Pattern formation can be controlled not only by thickness but also by swelling ratio, which may be useful for creating novel pattern templates. PMID:21557556

  10. Epoxides, cyclic sulfites, and sulfate from natural pentacyclic triterpenoids: theoretical calculations and chemical transformations.

    PubMed

    García-Granados, Andrés; López, Pilar E; Melguizo, Enrique; Moliz, Juan N; Parra, Andrés; Simeó, Yolanda; Dobado, José A

    2003-06-13

    Several triterpenic derivatives, with the A-ring functionalized, were semisynthesized from oleanolic and maslinic acids. The reactivities of sulfites, sulfate, and epoxides in these triterpene compounds were investigated under different reaction conditions. Moreover, contracted A-ring triterpenes (five-membered rings) were obtained, by different treatments of the sulfate 7. From the epoxide 8, deoxygenated and halohydrin derivatives were semisynthesized with several nucleophiles. Ozonolysis and Beckmann reactions were used to yield 4-aza compounds, from five-membered ring olanediene triterpenes. The X-ray structure of sulfate 7 is given and compared with density functional theory geometries. Theoretical (13)C and (1)H chemical shifts (gauge-invariant atomic orbital method at the B3LYP/6-31G*//B3LYP/6-31G* level) and (3)J(H,H) coupling constants were calculated for compounds 5-9 and 34-36, identifying the (R)- or (S)-sulfur and alpha- or beta-epoxide configurations together with 4-aza or 3-aza structures.

  11. Sulfite determination by a biosensor based on bay leaf tissue homogenate: very simple and economical method.

    PubMed

    Teke, Mustafa; Sezgintürk, Mustafa Kemal; Dinçkaya, Erhan

    2009-01-01

    Of all the food additives for which the FDA has received adverse reaction reports, the ones that most closely resemble true allergens are sulfur-based preservatives. Sulfites are used primarily as antioxidants to prevent or reduce discoloration of light-colored fruits and vegetables, such as dried apples and potatoes, and to inhibit the growth of microorganisms in fermented foods such as wine. This work aims to prepare an electrochemical biosensor based on bay leaf tissue homogenate that contains polyphenol oxidase enzyme abundantly for sulfite detection in foods. The principle of the biosensor is based on the inhibition effect of sulfites on polyphenol oxidase in the bioactive layer. Optimum conditions for the biosensor, such as temperature and pH, were investigated. Some stability parameters of the biosensor were also identified. The biosensor showed a linear calibration graph in the range of 25-100 microM sulfite. The biosensor presents a very simple, economical, reliable, and feasible method for sulfite detection in foods. PMID:19418312

  12. Influence of copper on the interaction between cytochrome c and sulfite in vitro.

    PubMed

    Wang, Jinsheng; Guo, Dongsheng; Yuan, Xiaoying

    2006-01-01

    The quantitative influence of copper on the interaction between cytochrome c and sulfite, which is a derivate of sulfur dioxide in the human body, has been studied by fluorescence spectrometry and ultraviolet absorption spectrometry in vitro. The results indicate that copper may intensely combine with protein component and ferroporphyrin component in cytochrome c at the concentration of 0.1 mM, and the respective association constants (K(A)) are 3.77 x 10(4) L mol(-1) and 9.38 x 10(3) L mol(-1). Sulfite has little interaction with the protein component in cytochrome c (K(A) = 0.094 L mol(-1)), at either low concentrations or relatively high concentrations (<0.15 M). However, it can react with the ferroporphyrin component in cytochrome c (K(A) = 4.297 L mol(-1)). After copper is added to the sulfite-cytochrome c binary systems, the reaction between sulfite and the protein component in cytochrome c is obviously strengthened at a low concentration (K(A) = 7.289 L mol(-1)), while the addition of copper merely has a little effect on the interaction between sulfite and the ferroporphyrin component in cytochrome c. PMID:17009250

  13. Development of an amperometric sulfite biosensor based on SO(x)/PBNPs/PPY modified ITO electrode.

    PubMed

    Rawal, Rachna; Pundir, C S

    2012-11-01

    A sulfite oxidase (SO(x)) (EC 1.8.3.1) purified from Syzygium cumini leaves was immobilized onto prussian blue nanoparticles/polypyrrole composite (PBNPs/PPY) electrodeposited onto the surface of indium tin oxide (ITO) electrode. An amperometric sulfite biosensor was fabricated using SO(x)/PBNPs/PPY/ITO electrode as working electrode, Ag/AgCl as standard and Pt wire as auxiliary electrode connected through a potentiostat. The working electrode was characterized by Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) before and after immobilization of SO(x). The biosensor showed optimum response within 2s, when operated at 20 mV s⁻¹ in 0.1M Tris-HCl buffer, pH 8.5 and at 35 °C. Linear range and minimum detection limit were 0.5-1000 μM and 0.12 μM (S/N=3) respectively. There was good correlation (r=0.99) between red wine samples sulfite value by standard DTNB method and the present method. The sensor was evaluated with 97% recovery of added sulfite in red wine samples and 2.2% and 4.3% within and between batch coefficients of variation respectively. The sensor was employed for determination of sulfite level in red and white wine samples. The enzyme electrode was used 200 times over a period of 3 months when stored at 4 °C.

  14. Value-Added Products from FGD Sulfite-Rich Scrubber Materials

    SciTech Connect

    Vivak Malhotra

    2010-01-31

    According to the American Coal Ash Association, about 29.25 million tons of flue gas desulfurization (FGD) byproducts were produced in the USA in 2003. Out of 29.25 million tons, 17.35 million tons were sulfite-rich scrubber materials. At present, unlike its cousin FGD gypsum, the prospect for effective utilization of sulfite-rich scrubber materials is not bright. In fact, almost 16.9 million tons are leftover every year. In our pursuit to mitigate the liability of sulfite-rich FGD scrubber materials' disposal, we are attempting to develop value-added products that can commercially compete. More specifically, for this Innovative Concept Phase I project, we have the following objectives: to characterize the sulfite-rich scrubber material for toxic metals; to optimize the co-blending and processing of scrubber material and natural byproducts; to formulate and develop structural composites from sulfite-rich scrubber material; and to evaluate the composites' mechanical properties and compare them with current products on the market. After successfully demonstrating the viability of our research, a more comprehensive approach will be proposed to take these value-added materials to fruition.

  15. Sulfite determination by a biosensor based on bay leaf tissue homogenate: very simple and economical method.

    PubMed

    Teke, Mustafa; Sezgintürk, Mustafa Kemal; Dinçkaya, Erhan

    2009-01-01

    Of all the food additives for which the FDA has received adverse reaction reports, the ones that most closely resemble true allergens are sulfur-based preservatives. Sulfites are used primarily as antioxidants to prevent or reduce discoloration of light-colored fruits and vegetables, such as dried apples and potatoes, and to inhibit the growth of microorganisms in fermented foods such as wine. This work aims to prepare an electrochemical biosensor based on bay leaf tissue homogenate that contains polyphenol oxidase enzyme abundantly for sulfite detection in foods. The principle of the biosensor is based on the inhibition effect of sulfites on polyphenol oxidase in the bioactive layer. Optimum conditions for the biosensor, such as temperature and pH, were investigated. Some stability parameters of the biosensor were also identified. The biosensor showed a linear calibration graph in the range of 25-100 microM sulfite. The biosensor presents a very simple, economical, reliable, and feasible method for sulfite detection in foods.

  16. Avoiding total reduced sulfur (TRS) emissions from sodium sulfite pulping recovery processes

    SciTech Connect

    Norman, J.C.; Sell, N.J. ); Ciriacks, J.C. )

    1990-06-01

    This paper reports that one of the current trends in paper-making with cellulose pulping is the use of high-yield processes. With yields greater than 65%, these processes include mechanical pulps (groundwood and thermomechanical pulps or TMP), and semichemical types (chemi-TMP or CTMP). Groundwood and TMP make up about 10% of North American pulp production. Semichemical pulp makes up about 7% and is mostly used for corrugating medium. High-yield pulping for linerboard, particularly using the alkaline sulfite process, is also likely to be used in the future. High-yield pulping is based primarily on the sulfite process using mostly sodium-based chemicals. A disadvantage of this process is the unavailability of a recovery system for the inorganic pulping chemicals. Generally, mills have not accepted any particular recovery system for this process. For this and other reasons, sulfite processes constitute only 3-4% of the total North American pulp production. If high-yield processes continue to increase in popularity, a sodium sulfite chemical recovery system will be needed. A number of chemical recovery systems have been developed in the past 30 years for sodium-based sulfite pulping processes, with most of the mills successfully using this process located in Scandinavia.

  17. Dissolution and crystallization of calcium sulfite platelets. Report for Sep 84-Aug 86

    SciTech Connect

    Gleason, C.L.; Rochelle, G.T.

    1987-01-01

    This paper discusses the dissolution and crystallization of calcium sulfite platelets. The rates of calcium sulfite dissolution and crystallization are important in slurry scrubbing processes for flue-gas desulfurization. The rates affect the scrubber solution composition, SO{sub 2} absorption, sulfite oxidation, and limestone utilization. The dissolution and crystallization rates of platelet shaped calcium sulfite crystals were measured in the pH stat apparatus. The solution pH was varied from 3.0 to 6.0. The effects of sulfate content in the solids and solution were also investigated. The measured rates for the platelets were compared to the rates previously determined for agglomerates. It was determined that there are subtle differences between platelet and agglomerated calcium sulfite. The platelet sample with low solid sulfate content dissolved and crystallized slower than the sample with a high solid sulfate content and the agglomerated samples. The inhibiting effect of dissolved sulfate was also greater for the low solid sulfate sample. The sample with a high solid sulfate content dissolved and crystallized at approximately the same rate as the agglomerates.

  18. Synthesis of cyclic sulfites from epoxides and sulfur dioxide with silica-immobilized homogeneous catalysts.

    PubMed

    Takenaka, Yasumasa; Kiyosu, Takahiro; Mori, Goro; Choi, Jun-Chul; Fukaya, Norihisa; Sakakura, Toshiyasu; Yasuda, Hiroyuki

    2012-01-01

    Quaternary ammonium- and amino-functionalized silica catalysts have been prepared for the selective synthesis of cyclic sulfites from epoxides and sulfur dioxide, demonstrating the effects of immobilizing the homogeneous catalysts on silica. The cycloaddition of sulfur dioxide to various epoxides was conducted under solvent-free conditions at 100 °C. The quaternary ammonium- and amino-functionalized silica catalysts produced cyclic sulfites in high yields (79-96 %) that are comparable to those produced by the homogeneous catalysts. The functionalized silica catalysts could be separated from the product solution by filtration, thereby avoiding the catalytic decomposition of the cyclic sulfite products upon distillation of the product solution. Heterogenization of a homogeneous catalyst by immobilization can, therefore, improve the efficiency of the purification of crude reaction products. Despite a decrease in catalytic activity after each recycling step, the heterogeneous pyridine-functionalized silica catalyst provided high yields after as many as five recycling processes.

  19. The influence of oxygen exchange between sulfite and water on the oxygen isotope composition of sulfate

    NASA Astrophysics Data System (ADS)

    Müller, I. A.; Brunner, B.

    2012-12-01

    Sulfate does not exchange oxygen with the water under most environmental conditions. Therefore, its oxygen isotope composition serves as an archive of past oxidative sulfur cycling. Studies on the oxygen isotope signature of sulfate produced from reduced sulfur compounds show varying relative contributions of two possible oxygen sources; molecular oxygen and water, and variable isotope fractionations relative to these two compounds. These discrepancies could be due to differences in the production and consumption of sulfuroxy intermediates which exchange oxygen with water. Thereby, the rate of oxygen exchange as well as the rate of oxidation depends on the pH. Studies on the oxygen isotope exchange effects between sulfuroxy intermediates and water and on the oxygen isotope effects during the oxidation of sulfuroxy intermediates are scarce, severely limiting the interpretability of oxygen isotope signatures in sulfate. Sulfite is often considered to be the last/final sulfuroxy intermediate in the oxidation of reduced sulfur compounds to sulfate and may, therefore, be pivotal in shaping the oxygen isotope signature of sulfate. We determined the oxygen isotope equilibrium fractionation between sulfite and water and used the obtained equilibrium value to determine the oxygen isotope effects in abiotic sulfite oxidation experiments. Our results demonstrate that natural variations in the oxygen isotope composition of sulfate produced by oxidative processes can be explained by differences in the interplay of the sulfite oxidation rate and oxygen isotope exchange rate between sulfite and water which both depend on pH conditions and availability of oxidizing agents (e.g. molecular oxygen or ferric iron). Our findings contribute to a more detailed mechanistic understanding of the oxidation of reduced sulfur compounds and underline the importance of sulfite as the final sulfuroxy intermediate in oxidative sulfur cycling.

  20. Probing the role of a conserved salt bridge in the intramolecular electron transfer kinetics of human sulfite oxidase.

    PubMed

    Johnson-Winters, Kayunta; Davis, Amanda C; Arnold, Anna R; Berry, Robert E; Tollin, Gordon; Enemark, John H

    2013-08-01

    Sulfite oxidase (SO) is a vital metabolic enzyme that catalyzes the oxidation of toxic sulfite to sulfate. The proposed mechanism of this molybdenum cofactor dependent enzyme involves two one-electron intramolecular electron transfer (IET) steps from the molybdenum center to the iron of the b 5-type heme and two one-electron intermolecular electron transfer steps from the heme to cytochrome c. This work focuses on how the electrostatic interaction between two conserved amino acid residues, R472 and D342, in human SO (hSO) affects catalysis. The hSO variants R472M, R472Q, R472K, R472D, and D342K were created to probe the effect of the position of the salt bridge charges, along with the interaction between these two residues. With the exception of R472K, these variants all showed a significant decrease in their IET rate constants, k et, relative to wild-type hSO, indicating that the salt bridge between residues 472 and 342 is important for rapid IET. Surprisingly, however, except for R472K and R472D, all of the variants show k cat values higher than their corresponding k et values. The turnover number for R472D is about the same as k et, which suggests that the change in this variant is rate-limiting in catalysis. Direct spectroelectrochemical determination of the Fe(III/II) reduction potentials of the heme and calculation of the Mo(VI/V) potentials revealed that all of the variants affected the redox potentials of both metal centers, probably due to changes in their environments. Thus, the position of the positive charge of R472 and that of the negative charge of D342 are both important in hSO, and changing either the position or the nature of these charges perturbs IET and catalysis.

  1. Exchangeable oxygens in the vicinity of the molybdenum center of the high-pH form of sulfite oxidase and sulfite dehydrogenase†

    PubMed Central

    Klein, Eric L.; Ganyushin, Dmitry; Johnson-Winters, Kayunta; Neese, Frank; Kappler, Ulrike; Enemark, John H.

    2009-01-01

    The electron spin echo envelope modulation (ESEEM) investigation of the high-pH (hpH) form of sulfite oxidase (SO) and sulfite dehydrogenase (SDH) prepared in buffer enriched with H2 17O reveals the presence of three types of exchangeable oxygen atoms at the molybdenum center. Two of these oxygen atoms belong to the equatorial OH ligand and the axial oxo ligand, and are characterized by 17O hyperfine interaction (hfi) constants of about 37 MHz and 6 MHz, respectively. The third oxygen has an isotropic hfi constant of 3–4 MHz and likely belongs to a hydroxyl moiety hydrogen-bonded to the equatorial OH ligand. This exchangeable oxygen atom is not observed in the ESEEM spectra of the Y236F mutant of SDH, where the active site tyrosine has been replaced by phenylalanine. PMID:19639147

  2. Pulsed EPR investigations of the Mo(V) centers of the R55Q and R55M variants of sulfite dehydrogenase from Starkeya novella

    PubMed Central

    Rapson, Trevor D.; Astashkin, Andrei V.; Johnson-Winters, Kayunta; Bernhardt, Paul V.; Raitsimring, Arnold M.

    2010-01-01

    Continuous-wave and pulsed electron paramagnetic resonance (EPR) spectroscopy have been used to characterize two variants of bacterial sulfite dehydrogenase (SDH) from Starkeya novella in which the conserved active-site arginine residue (R55) is replaced by a neutral amino acid residue. Substitution by the hydrophobic methionine residue (SDHR55M) has essentially no effect on the pH dependence of the EPR properties of the Mo(V) center, even though the X-ray structure of this variant shows that the methionine residue is rotated away from the Mo center and a sulfate anion is present in the active-site pocket (Bailey et al. in J Biol Chem 284:2053–2063, 2009). For SDHR55M only the high-pH form is observed, and samples prepared in H217O-enriched buffer show essentially the same 17O hyperfine interaction and nuclear quadrupole interaction parameters as SDHWT enzyme. However, the pH dependence of the EPR spectra of SDHR55Q, in which the positively charged arginine is replaced by the neutral hydrophilic glutamine, differs significantly from that of SDHWT. For SDHR55Q the blocked form with bound sulfate is generated at low pH, as verified by 33S couplings observed upon reduction with 33S-labeled sulfite. This observation of bound sulfate for SDHR55Q supports our previous hypothesis that sulfite-oxidizing enzymes can exhibit multiple pathways for electron transfer and product release (Emesh et al. in Biochemistry 48:2156–2163, 2009). At pH ≥ 8 the high-pH form dominates for SDHR55Q. PMID:20084533

  3. Applications of pulsed EPR spectroscopy to structural studies of sulfite oxidizing enzymes

    SciTech Connect

    Klein, Eric L.; Astashkin, Andrei V.; Raitsimring, Arnold M.; Enemark, John H.

    2013-01-01

    Sulfite oxidizing enzymes (SOEs), including sulfite oxidase (SO) and bacterial sulfite dehydrogenase (SDH), catalyze the oxidation of sulfite (SO32-) to sulfate (SO42-). The active sites of SO and SDH are nearly identical, each having a 5-coordinate, pseudo-square-pyramidal Mo with an axial oxo ligand and three equatorial sulfur donor atoms. One sulfur is from a conserved Cys residue and two are from a pyranopterindithiolene (molybdopterin, MPT) cofactor. The identity of the remaining equatorial ligand, which is solvent-exposed, varies during the catalytic cycle. Numerous in vitro studies, particularly those involving electron paramagnetic resonance (EPR) spectroscopy of the Mo(V) states of SOEs, have shown that the identity and orientation of this exchangeable equatorial ligand depends on the buffer pH, the presence and concentration of certain anions in the buffer, as well as specific point mutations in the protein. Until very recently, however, EPR has not been a practical technique for directly probing specific structures in which the solvent-exposed, exchangeable ligand is an O, OH-, H2O, SO32-, or SO42- group, because the primary O and S isotopes (16O and 32S) are magnetically silent (I = 0). This review focuses on the recent advances in the use of isotopic labeling, variable-frequency high resolution pulsed EPR spectroscopy, synthetic model compounds, and DFT calculations to elucidate the roles of various anions, point mutations, and steric factors in the formation, stabilization, and transformation of SOE active site structures.

  4. Decreased immunoglobulin E (IgE) binding to cashew allergens following sodium sulfite treatment and heating.

    PubMed

    Mattison, Christopher P; Desormeaux, Wendy A; Wasserman, Richard L; Yoshioka-Tarver, Megumi; Condon, Brian; Grimm, Casey C

    2014-07-16

    Cashew nut and other nut allergies can result in serious and sometimes life-threatening reactions. Linear and conformational epitopes within food allergens are important for immunoglobulin E (IgE) binding. Methods that disrupt allergen structure can lower IgE binding and lessen the likelihood of food allergy reactions. Previous structural and biochemical data have indicated that 2S albumins from tree nuts and peanuts are potent allergens, and that their structures are sensitive to strong reducing agents such as dithiothreitol. This study demonstrates that the generally regarded as safe (GRAS) compound sodium sulfite effectively disrupted the structure of the cashew 2S albumin, Ana o 3, in a temperature-dependent manner. This study also showed that sulfite is effective at disrupting the disulfide bond within the cashew legumin, Ana o 2. Immunoblotting and ELISA demonstrated that the binding of cashew proteins by rabbit IgG or IgE from cashew-allergic patients was markedly lowered following treatment with sodium sulfite and heating. The results indicate that incorporation of sodium sulfite, or other food grade reagents with similar redox potential, may be useful processing methods to lower or eliminate IgE binding to food allergens. PMID:24926808

  5. Decreased immunoglobulin E (IgE) binding to cashew allergens following sodium sulfite treatment and heating.

    PubMed

    Mattison, Christopher P; Desormeaux, Wendy A; Wasserman, Richard L; Yoshioka-Tarver, Megumi; Condon, Brian; Grimm, Casey C

    2014-07-16

    Cashew nut and other nut allergies can result in serious and sometimes life-threatening reactions. Linear and conformational epitopes within food allergens are important for immunoglobulin E (IgE) binding. Methods that disrupt allergen structure can lower IgE binding and lessen the likelihood of food allergy reactions. Previous structural and biochemical data have indicated that 2S albumins from tree nuts and peanuts are potent allergens, and that their structures are sensitive to strong reducing agents such as dithiothreitol. This study demonstrates that the generally regarded as safe (GRAS) compound sodium sulfite effectively disrupted the structure of the cashew 2S albumin, Ana o 3, in a temperature-dependent manner. This study also showed that sulfite is effective at disrupting the disulfide bond within the cashew legumin, Ana o 2. Immunoblotting and ELISA demonstrated that the binding of cashew proteins by rabbit IgG or IgE from cashew-allergic patients was markedly lowered following treatment with sodium sulfite and heating. The results indicate that incorporation of sodium sulfite, or other food grade reagents with similar redox potential, may be useful processing methods to lower or eliminate IgE binding to food allergens.

  6. Generation and characterization of sodium sulfite aerosols for applications in inhalation toxicologic research

    SciTech Connect

    Dasgupta, P.K.; Raabe, O.G.; Duvall, T.R.; Tarkington, B.K.

    1980-09-01

    A method was developed for generation of submicrometer aerosols of sodium sulfite suitable for use in inhalation toxicologic research. Concentrations ranging up to about 30 mg/m/sup 3/Na/sub 2/SO/sub 3/ were achieved in a 0.44 m/sup 3/ exposure chamber with an air flow rate of 0.20 m/sup 3//min for periods up to 16 days. The coefficient of variation of the sulfite aerosol mass concentration was about 4% during a typical exposure period. The measured mass median aerodynamic diameters (MMAD/sub ar/) of the generated aerosols were 1.2 (+-0.2SD) ..mu..m with a geometric standard deviation (sigma g) of 1.9 (+-0.3SD). The chamber was sampled for gas phase SO/sub 2/ concentration, and aerosol samples were analyzed for particulate sulfite and sulfate. The fraction of sulfur as sulfite in the aerosol was usually 95% and was always greater than 90%. Gas phase SO/sub 2/ amounted to less than 2% of the total S(IV) present in the chamber.

  7. Simple Method for Simultaneous Determination of Carbonate, Sulfite and Hydroxide in Solution

    NASA Astrophysics Data System (ADS)

    Al-Itawi, Hossam I.; Al-Ebaisat, Hamdan; Al-Garaleh, Mazen

    A method is proposed for the simultaneous determination of carbon dioxide and sulphur dioxide in a complex matrices. The method involves salvation of the tow gases in Sodium Hydroxide solution followed by simultaneous determination of the three species (carbonate, sulfite and hydroxide) using conductometric and potentiometric titration. What set this method apart from other determination methods it`s simplicity.

  8. Effects of commonly used oilfield chemicals on the rate of oxygen scavenging by sulfite/bisulfite

    SciTech Connect

    Braga, T.G.

    1987-05-01

    The effect of common oilfield biocides, corrosion inhibitors, scale preventives, and alcohols on the rate of O/sub 2/ scavenging by sulfite/bisulfite is described. Emphasis is placed on the effect of the functional group of each of the chemical types. An attempt is made to explain the results in terms of the free-radical mechanism.

  9. 40 CFR 63.444 - Standards for the pulping system at sulfite processes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sodium-based sulfite pulping process shall: (i) Emit no more than 0.44 kilograms of total HAP or methanol... more than 1.1 kilograms of total HAP or methanol per megagram (2.2 pounds per ton) of ODP; or...

  10. Development of a liquid chromatography-tandem mass spectrometry method for the determination of sulfite in food.

    PubMed

    Robbins, Katherine S; Shah, Romina; MacMahon, Shaun; de Jager, Lowri S

    2015-06-01

    Sulfites are widely used food preservatives that can cause severe reactions in sensitive individuals. As a result, the U.S. FDA requires that sulfites be listed on the label of any food product containing >10 mg/kg (ppm) sulfite (measured as sulfur dioxide). Currently, the optimized Monier-Williams (MW) method (AOAC Official Method 990.28) is the most common approach for determining sulfite concentrations in food samples. However, this method is time-consuming and lacks specificity in certain matrices. An improved rapid, sensitive, and selective method has been developed using electrospray ionization (ESI) high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of sulfite in various food matrices. A total of 12 different types of foods were evaluated. These included dried fruits and vegetables, frozen seafood, sweeteners, and juices. The matrix is extracted with a buffered formaldehyde solution, converting free and reversibly bound sulfite to the stable formaldehyde adduct, hydroxymethylsulfonate (HMS). Extracts are prepared for injection using a C18 SPE cartridge to remove any lipophilic compounds. HMS is then separated from other matrix components using hydrophilic interaction chromatography (HILIC) and detected using multiple reaction monitoring (MRM). The method was validated at 5 concentrations in 12 food matrices. Accuracy data showed spiked recoveries ranging from 84 to 115% in representative foods. Six commercially available sulfited products were analyzed using the LC-MS/MS method, as well as the MW method, to determine if differences exist.

  11. Survey of sulfites in wine and various Turkish food and food products intended for export, 2007-2010.

    PubMed

    Ulca, P; Öztürk, Y; Senyuva, H Z

    2011-01-01

    Surveys were carried out between 2007 and 2010 to determine the total levels of sulfites in 1245 samples of wines, dried apricots, dried vegetables, nuts, juices and purees, frozen foods and cereals containing dried fruit supplied by food inspectors and by food producers for testing or for export certification. Sulfite analysis of wine was carried out using the Ripper method with an LOQ of 5 mg l(-1) and for dried and other foods the Monier-Williams distillation procedure was employed with an LOQ of 10 mg kg(-1). In the survey all wines contained measurable sulfites, but with the exception of one sample of white wine they were otherwise below Turkish Food Codex limits of 160 mg kg(-1) for red wine, 210 mg kg(-1) to white wine and 235 mg kg(-1) for sparkling wine. None of the cereal products, frozen foods, juices or purees contained sulfites above 10 mg kg(-1). However, all dried apricot samples contained significant levels of sulfite with around 40% having levels exceeding the Turkish limit of 2000 mg kg(-1). Significant levels of sulfite were found in other samples of dried fruit with even a fruit and nut bar containing 1395 mg kg(-1) of sulfite, suggesting the dried fruit ingredients contained levels above regulatory limits.

  12. Sulfite-mediated oxidation of myeloperoxidase to a free radical: immuno-spin trapping detection in human neutrophils.

    PubMed

    Ranguelova, Kalina; Rice, Annette B; Lardinois, Olivier M; Triquigneaux, Mathilde; Steinckwich, Natacha; Deterding, Leesa J; Garantziotis, Stavros; Mason, Ronald P

    2013-07-01

    Previous studies focused on catalyzed oxidation of (bi)sulfite, leading to the formation of the reactive sulfur trioxide ((•)SO3(-)), peroxymonosulfate ((-)O3SOO(•)), and sulfate (SO4(•-)) anion radicals, which can damage target proteins and oxidize them to protein radicals. It is known that these very reactive sulfur- and oxygen-centered radicals can be formed by oxidation of (bi)sulfite by peroxidases. Myeloperoxidase (MPO), an abundant heme protein secreted from activated neutrophils that play a central role in host defense mechanisms, allergic reactions, and asthma, is a likely candidate for initiating the respiratory damage caused by sulfur dioxide. The objective of this study was to examine the oxidative damage caused by (bi)sulfite-derived free radicals in human neutrophils through formation of protein radicals. We used immuno-spin trapping and confocal microscopy to study the protein oxidations driven by sulfite-derived radicals. We found that the presence of sulfite can cause MPO-catalyzed oxidation of MPO to a protein radical in phorbol 12-myristate 13-acetate-activated human neutrophils. We trapped the MPO-derived radicals in situ using the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide and detected them immunologically as nitrone adducts in cells. Our present study demonstrates that myeloperoxidase initiates (bi)sulfite oxidation leading to MPO radical damage, possibly leading to (bi)sulfite-exacerbated allergic reactions.

  13. Isolation of Assimilatory- and Dissimilatory-Type Sulfite Reductases from Desulfovibrio vulgaris

    PubMed Central

    Lee, Jin-Po; LeGall, Jean; Peck, Harry D.

    1973-01-01

    Bisulfite reductase (desulfoviridin) and an assimilatory sulfite reductase have been purified from extracts of Desulfovibrio vulgaris. The bisulfite reductase has absorption maxima at 628, 580, 408, 390, and 279 nm, and a molecular weight of 226,000 by sedimentation equilibrium, and was judged to be free of other proteins by disk electrophoresis and ultracentrifugation. On gels, purified bisulfite reductase exhibited two green bands which coincided with activity and protein. The enzyme appears to be a tetramer but was shown to have two different types of subunits having molecular weights of 42,000 and 50,000. The chromophore did not form an alkaline ferrohemochromogen, was not reduced with dithionite or borohydride, and did not form a spectrally visible complex with CO. The assimilatory sulfite reductase has absorption maxima at 590, 545, 405 and 275 nm and a molecular weight of 26,800, and appears to consist of a single polypeptide chain as it is not dissociated into subunits by sodium dodecyl sulfate. By disk electrophoresis, purified sulfite reductase exhibited a single greenish-brown band which coincided with activity and protein. The sole product of the reduction was sulfide, and the chromophore was reduced by borohydride in the presence of sulfite. Carbon monoxide reacted with the reduced chromophore but it did not form a typical pyridine ferrohemochromogen. Thiosulfate, trithionate, and tetrathionate were not reduced by either enzyme preparation. In the presence of 8 M urea, the spectrum of bisulfite reductase resembles that of the sulfite reductase, thus suggesting a chemical relationship between the two chromophores. Images PMID:4725615

  14. The octahaem MccA is a haem c-copper sulfite reductase.

    PubMed

    Hermann, Bianca; Kern, Melanie; La Pietra, Luigi; Simon, Jörg; Einsle, Oliver

    2015-04-30

    The six-electron reduction of sulfite to sulfide is the pivot point of the biogeochemical cycle of the element sulfur. The octahaem cytochrome c MccA (also known as SirA) catalyses this reaction for dissimilatory sulfite utilization by various bacteria. It is distinct from known sulfite reductases because it has a substantially higher catalytic activity and a relatively low reactivity towards nitrite. The mechanistic reasons for the increased efficiency of MccA remain to be elucidated. Here we show that anoxically purified MccA exhibited a 2- to 5.5-fold higher specific sulfite reductase activity than the enzyme isolated under oxic conditions. We determined the three-dimensional structure of MccA to 2.2 Å resolution by single-wavelength anomalous dispersion. We find a homotrimer with an unprecedented fold and haem arrangement, as well as a haem bound to a CX15CH motif. The heterobimetallic active-site haem 2 has a Cu(I) ion juxtaposed to a haem c at a Fe-Cu distance of 4.4 Å. While the combination of metals is reminiscent of respiratory haem-copper oxidases, the oxidation-labile Cu(I) centre of MccA did not seem to undergo a redox transition during catalysis. Intact MccA tightly bound SO2 at haem 2, a dehydration product of the substrate sulfite that was partially turned over due to photoreduction by X-ray irradiation, yielding the reaction intermediate SO. Our data show the biometal copper in a new context and function and provide a chemical rationale for the comparatively high catalytic activity of MccA.

  15. Value-Added Products From FGD Sulfite-Rich Scrubber Materials

    SciTech Connect

    Vivak M. Malhotra

    2006-09-30

    Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber materials are produced every year in the USA. In fact, at present, the production of wet sulfite-rich scrubber cake outstrips the production of wet sulfate-rich scrubber cake by about 6 million tons per year. However, most of the utilization focus has centered on FGD gypsum. Therefore, we have recently initiated research on developing new strategies for the economical, but environmentally-sound, utilization of sulfite-rich scrubber material. In this exploratory project (Phase I), we attempted to ascertain whether it is feasible to develop reconstituted wood replacement products from sulfite-rich scrubber material. In pursuit of this goal, we characterized two different wet sulfite-rich scrubber materials, obtained from two power plants burning Midwestern coal, for their suitability for the development of value-added products. The overall strategy adopted was to fabricate composites where the largest ingredient was scrubber material with additional crop materials as additives. Our results suggested that it may be feasible to develop composites with flexural strength as high as 40 MPa (5800 psi) without the addition of external polymers. We also attempted to develop load-bearing composites from scrubber material, natural fibers, and phenolic polymer. The polymer-to-solid ratio was limited to {le} 0.4. The formulated composites showed flexural strengths as high as 73 MPa (10,585 psi). We plan to harness the research outcomes from Phase I to develop parameters required to upscale our value-added products in Phase II.

  16. The roles of polycarboxylates in Cr(VI)/sulfite reaction system: Involvement of reactive oxygen species and intramolecular electron transfer.

    PubMed

    Jiang, Bo; Wang, Xianli; Liu, Yukun; Wang, Zhaohui; Zheng, Jingtang; Wu, Mingbo

    2016-03-01

    In this study, the effects of polycarboxylates on both Cr(VI) reduction and S(IV) consumption in Cr(VI)/S(IV) system was investigated in acidic solution. Under aerobic condition, the productions of reactive oxygen species (ROS), i.e., SO4(-) and OH, have been confirmed in S(IV) reducing Cr(VI) process by using electron spin resonance and fluorescence spectrum techniques, leading to the excess consumption of S(IV). However, when polycarboxylates (oxalic, citric, malic and tartaric acid) were present in Cr(VI)/S(IV) system, the affinity of polycarboxylates to CrSO6(2-) can greatly promote the reduction of Cr(VI) via expanding the coordination of Cr(VI) species from tetrahedron to hexahedron. Besides, as alternatives to S(IV), these polycarboxylates can also act as electron donors for Cr(VI) reduction via intramolecular electron transfer reaction, which is dependent on the energies of the highest occupied molecular orbital of these polycarboxylates. Notably, the variant electron donating capacity of these polycarboxylates resulted in different yield of ROS and therefore the oxidation efficiencies of other pollutants, e.g., rhodamine B and As(III). Generally, this study does not only shed light on the mechanism of S(IV) reducing Cr(VI) process mediated by polycarboxylates, but also provides an escalated, cost-effective and green strategy for the remediation of Cr(VI) using sulfite as a reductant. PMID:26610099

  17. Spectrophotometric study and potentiometric titration between sulfite and nitrite ions using acetaldehyde complex of nitroprusside as a carrier

    SciTech Connect

    Ahmed, Y.Z.; Abd-Elmottalb, M.

    1985-11-01

    A complex between sodium nitroprusside (NP) and acetaldehyde of 1:1 in aqueous solution of pH 10 has been prepared and used as an analytical reagent for the spectrophotometric determination of sulfite and nitrite ions. Nitrite ion can be titrated against sulfite ion and vise versa in equivalent amounts with high accuracy in the presence of the acetaldehyde complex of nitroprusside as a carrier using a potentiometric titration technique. 9 references, 3 figures, 2 tables.

  18. Crystallization of calcium sulfate dihydrate and calcium sulfite hemihydrate from synthetic flue gas desulfurization solutions: Final report

    SciTech Connect

    Trofe, T.W.; Fishman, V.A.; Meserole, F.B.

    1986-10-01

    The precipitation of calcium sulfate dihydrate (CaSO/sub 4/.2H/sub 2/O) and calcium sulfite hemihydrate (CaSO/sub 3/.1/2H/sub 2/O) from high, up to 240,000 mg/L, total dissolved solids (TDS) solutions was studied at 50/sup 0/C. The solutions were selected to cover a range of solution compositions of magnesium, calcium, sodium, chloride, and sulfate. Precipitation rates along with crystal habit and size changes were measured to determine the effects of these dissolved species as compared to dilute solution conditions. Calcium sulfate dihydrate (gypsum) precipitation rate was accelerated in the high TDS solutions, especially those containing chloride ion. Alternatively, calcium sulfite hemihydrate precipitation rate was found to be faster in high sulfate ion containing solutions. Sodium ion appears to produce gypsum crystals more columnar in habit while solutions containing high amounts of calcium produced very lamellar gypsum crystals. Solutions containing magnesium produced acicular gypsum crystals. Calcium sulfite hemihydrate solids precipitated from solutions containing high sulfate concentrations were rod shaped and globular as compared to the lamellar calcium sulfite hemihydrate crystals precipitated from high chloride and dilute solution liquors. Calcium sulfate-calcium sulfite solid solutions were characterized using infrared spectroscopy. Ion scavenging of Na, Mg, and Cl by gypsum and calcium sulfite solids precipitated from these high TDS solutions was also investigated. 10 refs., 21 figs., 13 tabs.

  19. Conversion of spent sulfite liquor into chromium lignosulfonates and its evaluation as a drilling fluid additive

    SciTech Connect

    Sharma, S.M.; Yen, T.F.

    1986-01-01

    The chemistry of Indian spent sulfite liquor and methods to isolate sodium lignosulfonates from it have been discussed earlier. It has been observed experimentally that spent sulfite liquor as such is not an effective oil-well drilling fluid additive. Although its sodium lignosulfonate derivatives exhibited some effectivity, they were not thermostable. An effort has been made to further improve the performance characteristics and chemical nature of the sodium lignosulfonate by chromium metal ion complexing, employing conductometric titration method. The resulting chromium lignosulfonates possess better chemical properties, thermal stability, and effectivity as oil-well drilling fluid additive. Synthesis of metal ion lignosulfonates would save a considerable amount of foreign exchange in India and lead to ''import substitution'' in oil exploration. Experimental details of chromium metal ion complexing of sodium lignosulfonate, its chemistry, and its industrial application as oil-well drilling fluid additive have been discussed.

  20. Method using lime slurry for regenerating sodium sulfite in double alkali flue gas desulfurization process

    SciTech Connect

    Dabbs, J.C.; Dauerman, L.; Delaney, B.; Rao, K.K.

    1981-05-12

    In the process of desulfurizing flue gases in which an alkaline solution of sodium, such as sodium sulfite or sodium hydroxide, is contacted with gases in a scrubber to produce a sodium bisulfite solution, an improved method is provided for substantially reducing the time and equipment required to regenerate the sodium solution. In the method, a lime slurry stream and a sodium bisulfite stream are conflowed into a bifurcated mixing nozzle having a pair of converging inlets and a common outlet. The confluence of the streams in the nozzle creates turbulence which causes the lime slurry to react substantially instantaneously with the sodium bisulfite solution to regenerate the sodium solution which is recycled to the scrubber and a calcium sulfite precipitate which is filtered from the sodium solution and discarded.

  1. Pattern formation in the thiourea-iodate-sulfite system: Spatial bistability, waves, and stationary patterns

    NASA Astrophysics Data System (ADS)

    Horváth, Judit; Szalai, István; De Kepper, Patrick

    2010-06-01

    We present a detailed study of the reaction-diffusion patterns observed in the thiourea-iodate-sulfite (TuIS) reaction, operated in open one-side-fed reactors. Besides spatial bistability and spatio-temporal oscillatory dynamics, this proton autoactivated reaction shows stationary patterns, as a result of two back-to-back Turing bifurcations, in the presence of a low-mobility proton binding agent (sodium polyacrylate). This is the third aqueous solution system to produce stationary patterns and the second to do this through a Turing bifurcation. The stationary pattern forming capacities of the reaction are explored through a systematic design method, which is applicable to other bistable and oscillatory reactions. The spatio-temporal dynamics of this reaction is compared with that of the previous ferrocyanide-iodate-sulfite mixed Landolt system.

  2. Control of crystal habit and particle morphology of calcium sulfite hemihydrate crystals

    NASA Astrophysics Data System (ADS)

    Chen, Pao-Chi; Tai, Clifford Y.; Shih, Shin-Min

    1992-09-01

    Using a pH-stat apparatus, we produced crystals of calcium sulfite hemihydrate in a semibatch crystallizer by reacting Ca(OH) 2 with NaHSO 3 under various operational conditions. The habits of calcium sulfite hemihydrate obtained in this study were acicular, long-platelet, platelet and tabular. Each of them was prone to form agglomerates, depending on the pH value, solution composition and concentration of additives. At low pH and high concentration of sodium bisulfite the agglomerate of acicular crystal would form. In contrast, platelet and tabular crystals and their agglomerates were obtained at high pH and low levels of sodium bisulfite concentration. The particle morphology was not significantly altered by the addition of EDTA and DMA, but the crystal habit was tabular at low EDTA concentration and became platelet as the EDTA concentration increased.

  3. Multicomponent Convection Induced by Fronts in the Chlorate-Sulfite Reaction

    NASA Technical Reports Server (NTRS)

    Nagy, Istvan P.; Pojman, John A.

    1993-01-01

    An application of a new method is presented for the measurement of the temperature profiles of chemical waves propagating through a solution. Using solutions of thermocolor materials, the temperature distribution caused by the heat released in the propagating chlorate oxidation of sulfite was visualized and recorded using digital image processing methods. After calibration, the temperature gradient was calculated from the gray scale value in a digitized image. Extensive multicomponent convection ('fingering') was induced by descending fronts. Only ascending fingers were observed because of the large thermal gradient that suppressed descending ones. The characteristics of the temperature profile were determined as a function of initial sulfite and chlorate concentration, and tube diameter. Unusual behavior was observed when the fronts propagated under conditions of continuously changing diameter in a conical vessel. Fingering occurred periodically in a front descending in a flask with an increasing diameter. However, when a front propagated down in flask whose diameter decreased, no multicomponent convection was observed.

  4. Effective Electrochemistry of Human Sulfite Oxidase Immobilized on Quantum-Dots-Modified Indium Tin Oxide Electrode.

    PubMed

    Zeng, Ting; Leimkühler, Silke; Koetz, Joachim; Wollenberger, Ulla

    2015-09-30

    The bioelectrocatalytic sulfite oxidation by human sulfite oxidase (hSO) on indium tin oxide (ITO) is reported, which is facilitated by functionalizing of the electrode surface with polyethylenimine (PEI)-entrapped CdS nanoparticles and enzyme. hSO was assembled onto the electrode with a high surface loading of electroactive enzyme. In the presence of sulfite but without additional mediators, a high bioelectrocatalytic current was generated. Reference experiments with only PEI showed direct electron transfer and catalytic activity of hSO, but these were less pronounced. The application of the polyelectrolyte-entrapped quantum dots (QDs) on ITO electrodes provides a compatible surface for enzyme binding with promotion of electron transfer. Variations of the buffer solution conditions, e.g., ionic strength, pH, viscosity, and the effect of oxygen, were studied in order to understand intramolecular and heterogeneous electron transfer from hSO to the electrode. The results are consistent with a model derived for the enzyme by using flash photolysis in solution and spectroelectrochemistry and molecular dynamic simulations of hSO on monolayer-modified gold electrodes. Moreover, for the first time a photoelectrochemical electrode involving immobilized hSO is demonstrated where photoexcitation of the CdS/hSO-modified electrode lead to an enhanced generation of bioelectrocatalytic currents upon sulfite addition. Oxidation starts already at the redox potential of the electron transfer domain of hSO and is greatly increased by application of a small overpotential to the CdS/hSO-modified ITO. PMID:26357959

  5. Effective Electrochemistry of Human Sulfite Oxidase Immobilized on Quantum-Dots-Modified Indium Tin Oxide Electrode.

    PubMed

    Zeng, Ting; Leimkühler, Silke; Koetz, Joachim; Wollenberger, Ulla

    2015-09-30

    The bioelectrocatalytic sulfite oxidation by human sulfite oxidase (hSO) on indium tin oxide (ITO) is reported, which is facilitated by functionalizing of the electrode surface with polyethylenimine (PEI)-entrapped CdS nanoparticles and enzyme. hSO was assembled onto the electrode with a high surface loading of electroactive enzyme. In the presence of sulfite but without additional mediators, a high bioelectrocatalytic current was generated. Reference experiments with only PEI showed direct electron transfer and catalytic activity of hSO, but these were less pronounced. The application of the polyelectrolyte-entrapped quantum dots (QDs) on ITO electrodes provides a compatible surface for enzyme binding with promotion of electron transfer. Variations of the buffer solution conditions, e.g., ionic strength, pH, viscosity, and the effect of oxygen, were studied in order to understand intramolecular and heterogeneous electron transfer from hSO to the electrode. The results are consistent with a model derived for the enzyme by using flash photolysis in solution and spectroelectrochemistry and molecular dynamic simulations of hSO on monolayer-modified gold electrodes. Moreover, for the first time a photoelectrochemical electrode involving immobilized hSO is demonstrated where photoexcitation of the CdS/hSO-modified electrode lead to an enhanced generation of bioelectrocatalytic currents upon sulfite addition. Oxidation starts already at the redox potential of the electron transfer domain of hSO and is greatly increased by application of a small overpotential to the CdS/hSO-modified ITO.

  6. Short circuiting a sulfite oxidising enzyme with direct electrochemistry: active site substitutions and their effect on catalysis and electron transfer.

    PubMed

    Rapson, Trevor D; Kappler, Ulrike; Hanson, Graeme R; Bernhardt, Paul V

    2011-01-01

    Sulfite dehydrogenase (SDH) from Starkeya novella is a heterodimeric enzyme comprising a Mo active site and a heme c electron relay, which mediates electron transfer from the Mo cofactor to cytochrome c following sulfite oxidation. Studies on the wild type enzyme (SDH(WT)) and its variants have identified key amino acids at the active site, specifically Arg-55 and His-57. We report the Mo(VI/V), Mo(V/IV) and Fe(III/II) (heme) redox potentials of the variants SDH(R55K), SDH(R55M), SDH(R55Q) and SDH(H57A) in comparison with those of SDH(WT). For SDH(R55M), SDH(R55Q) and SDH(H57A) the heme potentials are lowered from ca. 240mV in SDH(WT) to ca. 200mV, while the heme potential in SDH(R55K) remains unchanged and the Mo redox potentials are not affected significantly in any of these variants. Protein film voltammetry reveals a pH dependence of the electrochemical catalytic half-wave potential (E(cat)) of -59mV/pH in SDH(WT) and SDH(R55K) which tracks the pH dependence of the Mo(VI/V) redox potential. By contrast, the catalytic potentials for SDH(R55M) and SDH(H57A) are pH-independent and follow the potential of the heme cofactor. These results highlight a switch in the pathway of electron exchange as a function of applied potential that is revealed by protein film voltammetry where an actuation of rate limiting intramolecular electron transfer (IET, Mo to heme) at high potential attenuates the catalytic current relative to faster, direct electron transfer (Mo to electrode) at lower potential. The same change in electron transfer pathway is linked to an unusual peak-shaped profile of the ideally sigmoidal steady state voltammogram in SDH(WT) alone, which has been associated with a potential dependent change in the orientation of the enzyme on the electrode surface. All other variants show purely sigmoidal voltammetry due to their inherently slower turnover numbers which are always lower than IET rates.

  7. Precipitating factors in asthma. Aspirin, sulfites, and other drugs and chemicals.

    PubMed

    Mathison, D A; Stevenson, D D; Simon, R A

    1985-01-01

    Several types of reactions to drugs and chemicals may precipitate or perpetuate asthmatic relapse. This review focuses on reactions to aspirin and sulfites. Approximately 40 percent of patients with rhinosinusitis, nasal polyps, and asthma and 5 to 10 percent of all asthmatic patients are sensitive to aspirin and aspirin-like nonsteroidal anti-inflammatory drugs at some time in their course. A prudent recommendation to all asthmatics is to substitute acetaminophen for aspirin. When aspirin/aspirin-like drug is essential for treatment of cardiovascular or musculoskeletal disorder, desensitization by cautious oral challenges with graded doses of aspirin can be accomplished. Treatment of the respiratory disorder per se by desensitization followed by daily therapeutic aspirin remains investigational. Sulfur dioxide and sulfites, commonly used as sanitizers and preservatives of foods and pharmaceuticals, may precipitate acute asthma in 5 percent or more of asthmatic patients. When the history suggests sulfite sensitivity, challenges can be used to confirm sensitivity and the patient counseled in avoidance of these chemicals. PMID:3880531

  8. Influence of the enzyme dissimilatory sulfite reductase on stable isotope fractionation during sulfate reduction

    NASA Astrophysics Data System (ADS)

    Mangalo, Muna; Einsiedl, Florian; Meckenstock, Rainer U.; Stichler, Willibald

    2008-03-01

    The stable isotopes of sulfate are often used as a tool to assess bacterial sulfate reduction on the macro scale. However, the mechanisms of stable isotope fractionation of sulfur and oxygen at the enzymatic level are not yet fully understood. In batch experiments with water enriched in 18O we investigated the effect of different nitrite concentrations on sulfur isotope fractionation by Desulfovibrio desulfuricans. With increasing nitrite concentrations, we found sulfur isotope enrichment factors ranging from -11.2 ± 1.8‰ to -22.5 ± 3.2‰. Furthermore, the δ18O values in the remaining sulfate increased from approximately 50-120‰ when 18O-enriched water was supplied. Since 18O-exchange with ambient water does not take place in sulfate, but rather in intermediates of the sulfate reduction pathway (e.g. SO32-), we suggest that nitrite affects the steady-state concentration and the extent of reoxidation of the metabolic intermediate sulfite to sulfate during sulfate reduction. Given that nitrite is known to inhibit the production of the enzyme dissimilatory sulfite reductase, our results suggest that the activity of the dissimilatory sulfite reductase regulates the kinetic isotope fractionation of sulfur and oxygen during bacterial sulfate reduction. Our novel results also imply that isotope fractionation during bacterial sulfate reduction strongly depends on the cell internal enzymatic regulation rather than on the physico-chemical features of the individual enzymes.

  9. Chemical and physical properties of high-yield alkaline sulfite green liquor

    SciTech Connect

    Sell, N.J.; Norman, J.C. . Natural and Applied Sciences)

    1993-11-01

    The majority of sodium sulfite pulping liquor recovery systems are based on the reductive burning of the spent liquor, followed by acidification of the resulting smelt solution by CO[sub 2]. This study investigated a number of the physical and chemical properties of the resulting green liquor which might be relevant to the optimum design of this type of sulfite and carbonate recovery system for an alkaline sulfite high-yield process. CO[sub 2] gas does generate H[sub 2]S when bubbled through green liquor; however, a large amount of solid soon is formed. Continuing the flow leads to increased amounts of H[sub 2]S, but the ratio of H[sub 2]S to CO[sub 2] remains less than 1.0. Solutions more highly concentrated in Na[sub 2]S absorb relatively more CO[sub 2], regardless of the ratios of H[sub 2]S to CO[sub 2] in the initial gas stream. The percentage of H[sub 2]S released increases with increasing Na[sub 2]S concentration. Stripping the green liquor with inert gas, steam, or vacuum does not improve the H[sub 2]S removal efficiency. The maximum CO[sub 2] pressure can be generated by decomposing pure 6 M NaHCO[sub 3]. If the starting material is a bicarbonate/carbonate mixture, conversion is incomplete and a portion of the NaHCO[sub 3] forms a dead load.

  10. Techno-economic evaluation of conditioning with sodium sulfite for bioethanol production from softwood.

    PubMed

    Cavka, Adnan; Martín, Carlos; Alriksson, Björn; Mörtsell, Marlene; Jönsson, Leif J

    2015-11-01

    Conditioning with reducing agents allows alleviation of inhibition of biocatalytic processes by toxic by-products generated during biomass pretreatment, without necessitating the introduction of a separate process step. In this work, conditioning of steam-pretreated spruce with sodium sulfite made it possible to lower the yeast and enzyme dosages in simultaneous saccharification and fermentation (SSF) to 1g/L and 5FPU/g WIS, respectively. Techno-economic evaluation indicates that the cost of sodium sulfite can be offset by benefits resulting from a reduction of either the yeast load by 0.68g/L or the enzyme load by 1FPU/g WIS. As those thresholds were surpassed, inclusion of conditioning can be justified. Another potential benefit results from shortening the SSF time, which would allow reducing the bioreactor volume and result in capital savings. Sodium sulfite conditioning emerges as an opportunity to lower the financial uncertainty and compensate the overall investment risk for commercializing a softwood-to-ethanol process. PMID:26232771

  11. Precipitating factors in asthma. Aspirin, sulfites, and other drugs and chemicals.

    PubMed

    Mathison, D A; Stevenson, D D; Simon, R A

    1985-01-01

    Several types of reactions to drugs and chemicals may precipitate or perpetuate asthmatic relapse. This review focuses on reactions to aspirin and sulfites. Approximately 40 percent of patients with rhinosinusitis, nasal polyps, and asthma and 5 to 10 percent of all asthmatic patients are sensitive to aspirin and aspirin-like nonsteroidal anti-inflammatory drugs at some time in their course. A prudent recommendation to all asthmatics is to substitute acetaminophen for aspirin. When aspirin/aspirin-like drug is essential for treatment of cardiovascular or musculoskeletal disorder, desensitization by cautious oral challenges with graded doses of aspirin can be accomplished. Treatment of the respiratory disorder per se by desensitization followed by daily therapeutic aspirin remains investigational. Sulfur dioxide and sulfites, commonly used as sanitizers and preservatives of foods and pharmaceuticals, may precipitate acute asthma in 5 percent or more of asthmatic patients. When the history suggests sulfite sensitivity, challenges can be used to confirm sensitivity and the patient counseled in avoidance of these chemicals.

  12. Usefulness of ytterbium(III) as analytical reagent for total sulfite determination in white wine samples.

    PubMed

    Rodríguez-Díaz, Rafael Carlos; Aguilar-Caballos, Maria Paz; Gómez-Hens, Agustina

    2004-12-29

    Ytterbium(III) is used as reagent for the determination of sulfite by measuring the formation of the Yb(III)-sulfite complex through the variation of the light scattering intensity with time. The low solubility of this complex causes an efficient dispersion of the radiation at 490 nm, which is measured at 980 nm. Each kinetic datum is automatically obtained in only 0.5 s by stopped-flow mixing technique. The application of the initial rate method using a long emission wavelength minimizes the potential interference of fluorescent background signals from the sample matrix. The dynamic range of the calibration graph is 1-250 microg/mL, and the calculated detection limit is 0.35 microg/mL. The precision, expressed as relative standard deviation, is <6%. The method has been applied to the determination of total sulfites in white wine samples, which requires only the sample dilution and the use of two aliquots to improve selectivity. However, the matrix effect found for red wines precludes the application of the method to the direct analysis of these samples. Analytical recoveries ranged from 96.0 to 106.7%. The results obtained with the proposed method agreed with those provided by the p-rosaniline method. Unlike this method, in which toxic reagents are required, the use of ytterbium(III) as analytical reagent shows the advantage of its low acute toxic rating.

  13. Hydrothermal syntheses, crystal structures and magnetic properties of two new mixed metal copper(I) sulfites.

    PubMed

    Li, Pei-Xin; Mao, Jiang-Gao

    2010-01-01

    Two new examples of mixed metal copper(I) sulfites, namely, Na3Mn2Cu(SO3)4(H2O)5 (1) and NaMn4Cu(SO3)5(H2O)3 (2), have been synthesized and structurally characterized. The 1D structure of 1 is built from a chain of [Mn2Cu(SO3)4]3- bridged by Na+ ions whereas the structure of 2 features a complicated 3D framework in which Mn8O36 octanuclear clusters are bridged by sulfite anions and copper(I) ions into a 3D [CuMn4(SO3)5(H2O)3]2- network. The eight-coordinated sodium(I) ions are located at the cavities of the 3D structure. In both compounds, the oxygen atoms of the sulfite anion are bonded to Mn(II) ions whereas the sulfur atom is coordinated to the Cu+ ion. Magnetic measurements indicate that there exists antiferromagnetic interactions between Mn(II) centers in both compounds.

  14. Co-fermentation of hexose and pentose sugars in a spent sulfite liquor matrix with genetically modified Saccharomyces cerevisiae.

    PubMed

    Novy, Vera; Krahulec, Stefan; Longus, Karin; Klimacek, Mario; Nidetzky, Bernd

    2013-02-01

    Spent sulfite liquor (SSL) is a by-product of pulp and paper manufacturing and is a promising substrate for second-generation bioethanol production. The Saccharomyces cerevisiae strain IBB10B05 presented herein for SSL fermentation was enabled to xylose utilization by metabolic pathway engineering and laboratory evolution. Two SSLs from different process stages and with variable dry matter content were analyzed; SSL-Thin (14%) and SSL-S2 (30%). Hexose and pentose fermentation by strain IBB10B05 was efficient in 70% SSL matrix without any pretreatment. Ethanol yields varied between 0.31 and 0.44g/g total sugar, depending on substrate and process conditions used. Control of pH at 7.0 effectively reduced the inhibition by the acetic acid contained in the SSLs (up to 9g/L), thus enhancing specific xylose uptake rates (q(Xylose)) as well as ethanol yields. The total molar yield of fermentation by-products (glycerol, xylitol) was constant (0.36±0.03mol/mol xylose) at different q(Xylose). Compound distribution changed with glycerol and xylitol being chiefly formed at low and high q(Xylose), respectively. PMID:23313691

  15. Metal sulfite/sulfate reactions in thermochemical hydrogen cycles

    SciTech Connect

    Mason, C.F.V.; Bowman, M.G.

    1980-01-01

    The thermochemical cycles which have been most extensively developed all involve the thermal decomposition of sulfuric acid which is corrosive. Metal sulfate cycles have been studied as a means of circumventing handling corrosive mixtures at high temperatures. However, these metal sulfate cycles still use an electrochemical step to produce H/sub 2/. Alternate H/sub 2/ producing steps to be used in conjunction with metal sulfates are examined.

  16. Theoretical estimation of equilibrium sulfur isotope fractionations among aqueous sulfite species: Implications for isotope models of microbial sulfate reduction

    NASA Astrophysics Data System (ADS)

    Eldridge, D. L.; Farquhar, J.; Guo, W.

    2015-12-01

    Sulfite (sensu lato), an intermediate in a variety sulfur redox processes, plays a particularly important role in microbial sulfate reduction. It exists intracellularly as multiple species between sets of enzymatic reactions that transform sulfate to sulfide, with the exact speciation depending on pH, T, and ionic strength. However, the complex speciation of sulfite is ignored in current isotope partitioning models of microbial sulfate reduction and simplified solely to the pyramidal SO32- (sulfite sensu stricto), due to a lack of appropriate constraints. We theoretically estimated the equilibrium sulfur isotope fractionations (33S/32S, 34S/32S, 36S/32S) among all documented sulfite species in aqueous solution, including sulfite (SO32-), bisulfite isomers and dimers ((HS)O3-, (HO)SO2-, S2O52-), and SO2(aq), through first principles quantum mechanical calculations. The calculations were performed at B3LYP/6-31+G(d,p) level using cluster models with 30-40 water molecules surrounding the solute. Our calculated equilibrium fractionation factors compare well to the available experimental constraints and suggest that the minor and often-ignored tetrahedral (HS)O3- isomer of bisulfite strongly influences isotope partitioning behavior in the sulfite system under most environmentally relevant conditions, particularly fractionation magnitudes and unusual temperature dependence. For example, we predict that sulfur isotope fractionation between sulfite and bulk bisulfite in solution should have an apparent inverse temperature dependence due to the influence of (HS)O3- and its increased stability at higher temperatures. Our findings highlight the need to appropriately account for speciation/isomerization of sulfur species in sulfur isotope studies. We will also present similar calculation results of other aqueous sulfur compounds (e.g., H2S/HS-, SO42-, S2O32-, S3O62-, and poorly documented SO22- species), and discuss the implication of our results for microbial sulfate

  17. Direct Analysis of Free and Sulfite-Bound Carbonyl Compounds in Wine by Two-Dimensional Quantitative Proton and Carbon Nuclear Magnetic Resonance Spectroscopy.

    PubMed

    Nikolantonaki, Maria; Magiatis, Prokopios; Waterhouse, Andrew L

    2015-11-01

    Recent developments that have accelerated 2D NMR methods and improved quantitation have made these methods accessible analytical procedures, and the large signal dispersion allows for the analysis of complex samples. Few natural samples are as complex as wine, so the application to challenges in wine analysis look promising. The analysis of carbonyl compounds in wine, key oxidation products, is complicated by a multitude of kinetically reversible adducts, such as acetals and sulfonates, so that sample preparation steps can generate complex interferences. These challenges could be overcome if the compounds could be quantified in situ. Here, two-dimensional ((1)H-(1)H) homonuclear and heteronuclear ((13)C-(1)H) single quantum correlations (correlation spectroscopy, COSY, and heteronuclear single quantum coherence, HSQC) nuclear magnetic resonance spectra of undiluted wine samples were observed at natural abundance. These techniques achieve simultaneous direct identification and quantitation of acetaldehyde, pyruvic acid, acetoin, methylglyoxal, and α-ketoglutaric acid in wine with only a small addition of D2O. It was also possible to observe and sometimes quantify the sulfite, hydrate, and acetal forms of the carbonyl compounds. The accuracy of the method was tested in wine samples by spiking with a mixture of all analytes at different concentrations. The method was applied to 15 wine samples of various vintages and grape varieties. The application of this method could provide a powerful tool to better understand the development, evolution, and perception of wine oxidation and insight into the impact of these sulfite bound carbonyls on antimicrobial and antioxidant action by SO2.

  18. Effects of inhaled acids on lung biochemistry

    SciTech Connect

    Last, J.A.

    1989-02-01

    Effects of respirable aerosols of sulfuric acid, ammonium sulfate, sodium sulfite, and ammonium persulfate on lungs of rats are reviewed. The literature regarding interactions between ozone or nitrogen dioxide and acidic aerosols (ammonium sulfate, sulfuric acid) is discussed. An unexpected interaction between nitrogen dioxide and sodium chloride aerosol is also discussed. An attempt is made to identify bases for prediction of how and when acid aerosols might potentiate effects of inhaled gases.

  19. Effects of inhaled acids on lung biochemistry.

    PubMed

    Last, J A

    1989-02-01

    Effects of respirable aerosols of sulfuric acid, ammonium sulfate, sodium sulfite, and ammonium persulfate on lungs of rats are reviewed. The literature regarding interactions between ozone or nitrogen dioxide and acidic aerosols (ammonium sulfate, sulfuric acid) is discussed. An unexpected interaction between nitrogen dioxide and sodium chloride aerosol is also discussed. An attempt is made to identify bases for prediction of how and when acid aerosols might potentiate effects of inhaled gases.

  20. Sulfite exchange dominates oxygen isotope compositions of sulfate produced from abiotic pyrite oxidation

    NASA Astrophysics Data System (ADS)

    Kohl, I. E.; Bao, H.

    2009-12-01

    The oxidation of reduced sulfur compounds (solid, liquid and gas phase) is of primary importance when attempting to understand the global sulfur and oxygen cycles as preserved in sulfate minerals. It has long been known that O2, H2O, and Fe3+ all play an important role during this oxidation process, especially during the oxidation of sulfide minerals. The exact role of each oxidant and/or oxygen source has yet to be experimentally determined for oxidation in aqueous solutions over a range of pH values. In addition, the reported air O2 signal being incorporated in product sulfate appears to be highly variable (9-60%), which could be due to the presence of multiple oxidation pathways or the inability of the traditional δ18O label to differentiate kinetic effects on the degree of oxygen exchange. Here we test the affect of pH dependent sulfite-water oxygen exchange rate and precipitation of ferric hydroxides on the produced sulfate’s O2/H2O ratio. Our experiments utilize a Δ17O isotope label in the solutions, enabling a quantitative determination of oxygen source ratios (O2 vs. H2O) in the produced sulfate. We oxidized crushed pyrite grains aerobically in sterile, buffered solutions at pH=2,7,9,10, and 11. A duplicate set was spiked with Fe3+. The results from the reactors indicate that despite the pH dependency of sulfite-water exchange rate, fast at low pH and slow at high pH, the stability of intermediates, thiosulfate and especially sulfite, in alkaline solutions allows the exchange to proceed to equilibrium. This resulted in sulfate produced above pH=9 to contain 21-24% air O2 signal, indicating the last oxidation step, producing sulfate from sulfite, proceeded with direct incorporation of dissolved air O2 as represented by equation (1). The role of Fe3+ under alkaline conditions was observed to be negligible. SO32- + 1/2O2 → SO42- (1) In the pH=2 reactor, the O2% in the produced sulfate was 21% with the addition of Fe3+, but was 28-29% without the Fe3

  1. Effects of the methyltrimethoxysilane coupling agent on phenolic and miscanthus composites containing calcium sulfite scrubber material

    NASA Astrophysics Data System (ADS)

    Jones, Sean

    The purpose of this research is to test the effects of methyltrimethoxysilane coupling agent on composite material containing calcium sulfite obtained from the Southern Illinois Power Co-operative. This scrubber material and the miscanthus plant are of interest due to their use in coal burning power plants to reduce toxic emission. When calcium sulfate is passed through coal fire gas emissions it absorbs mercury and sulfur. In these composites it is used as filler to reduce cost. Miscanthus is a source of both cellulose reinforcement and some natural resin. This plant has low care requirements, little mineral content, useful energy return, and positive environmental effects. Under investigation is whether a post-cure procedure or a silane coupling agent will positively impact the composite. Hot pressing alone may not be enough to fully cure the phenolic. It is hoped that the silane will increase the strength characteristics of the composite by enhancing adhesion between the calcium sulfite and phenolic resin. Possible effects on the miscanthus by the silane will also be tested. Phenolic is being utilized because of its recycling and biodegradable properties along with cost effectiveness in mass production. Composite mechanical performance was measured through 3-point bending to measure flexural strength and strain at breakage. A dynamic mechanical analyzer (DMA) was used to find thermomechanical properties. The post-cure was found to be effective, particularly on the final composite containing silane. When methyltrimethoxysilane was added to the miscanthus prior to fabrication, it was found to reduce flexural strength and density. However the addition of methyltrimethoxysilane to the calcium sulfite altered thermo-mechanical properties to a state more like pure phenolic, with added flexibility and thermal stability.

  2. Kinetic and mechanistic study of reaction between sulfide and sulfite in aqueous solution

    SciTech Connect

    Siu, T.; Jia, C.Q.

    1999-10-01

    The reaction between sulfide and sulfite in neutral to weak alkaline aqueous solutions was studied by following thiosulfate and sulfite concentrations using ion chromatography. The thiosulfate formation rate from the reaction 2HS{sup {minus}} + 4HSO{sub 3}{sup {minus}} {yields} 3S{sub 2}O{sub 3}{sup 2{minus}} + 3H{sub 2}O at pH 8 to 9 was found to be d[S{sub 2}O{sub 3}{sup 2{minus}}]/dt = k{sub A}[HS{sup {minus}}][HSO{sub 3}{sup {minus}}]{sup 2}, where k{sub A} = 1.1 x 10{sup 12} exp({minus}48000/RT) M{sup {minus}2} s{sup {minus}1}. A mechanism for this reaction has been proposed with disulfite (S{sub 2}O{sub 5}{sup 2{minus}}) and HSO{sub 2}{sup {minus}} intermediates. The measured rate of sulfite disappearance was higher than that calculated from the stoichiometry of the above reaction. This phenomenon is attributed to other reactions, that consume sulfite and form other sulfur compounds such as polythionates, polysulfides, and elemental sulfur. These reactions were treated as a single reaction, whose rate was found to be ({minus}d[HSO{sub 3}{sup {minus}}]/dt){sub B} = k{sub B}[H{sup +}]{sup {minus}0.6}[HS{sup {minus}}]{sup 0.7}[HSO{sub 3}{sup {minus}}]{sup 1.5}, where k{sub B} = 5 x 10{sup {minus}5} M{sup {minus}0.6} s{sup {minus}1} at 20 C. A kinetic model was established on the basis of the kinetic data obtained in this and a previous work. The experimental data at pH 7 agreed with the model prediction in a satisfactory manner. The biphasic behavior of thiosulfate is considered to be critical in developing a new sulfur-producing flue gas desulfurization (SP-FGD) process based on sulfur dioxide absorption using sodium sulfide solution.

  3. Intramolecular electron transfer in sulfite oxidizing enzymes: elucidating the role of a conserved active site arginine†

    PubMed Central

    Emesh, Safia; Rapson, Trevor D.; Rajapakshe, S. Asha; Kappler, Ulrike; Bernhardt, Paul V.; Tollin, Gordon; Enemark, John H.

    2009-01-01

    All reported sulfite oxidizing enzymes have a conserved arginine in their active site which hydrogen bonds to the equatorial oxygen ligand on the Mo atom. Previous studies on the pathogenic R160Q mutant of human sulfite oxidase (HSO) have shown that Mo-heme intramolecular electron transfer (IET) is dramatically slowed when positive charge is lost at this position. In order to better understand the function that this conserved positively charged residue plays in IET, we have studied the equivalent uncharged substitutions, R55Q and R55M, as well as the positively charged substitution, R55K, in bacterial sulfite dehydrogenase (SDH). The heme and molybdenum cofactor (Moco) subunits are tightly associated in SDH, which makes it an ideal system for increasing the understanding of residue function in IET without the added complexity of the inter-domain movement that occurs in HSO. Unexpectedly, the uncharged SDH variants (R55Q and R55M) showed increased IET rate constants relative to the wildtype (3–4 fold) when studied by laser flash photolysis. The gain in function observed in SDHR55Q and SDHR55M suggests that the reduction of IET seen in HSOR160Q is not due to a required role of this residue in the IET pathway itself, but to the fact that it plays an important role in heme orientation during the inter-domain movement necessary for IET in HSO (as seen in viscosity experiments). The pH profiles of SDHwt, SDHR55M, and SDHR55Q show that the arginine substitution also alters the behavior of the Mo-heme IET equilibrium (Keq) and rate constants (ket) of both variants with respect to SDHWT enzyme. SDHWT has a ket that is independent of pH and a Keq that increases as pH decreases, whereas both SDHR55M and SDHR55Q have a ket that increases as pH decreases, and SDHR55M has a Keq that is pH independent. IET in the SDHR55Q variant is inhibited by sulfate in laser flash photolysis experiments, a behavior that differs from SDHWT, but which also occurs in HSO. IET in SDHR55K is

  4. Determination and application of the equilibrium oxygen isotope effect between water and sulfite

    NASA Astrophysics Data System (ADS)

    Wankel, Scott D.; Bradley, Alexander S.; Eldridge, Daniel L.; Johnston, David T.

    2014-01-01

    The information encoded by the two stable isotope systems in sulfate (δ34SSO4 and δ18OSO4) has been widely applied to aid reconstructions of both modern and ancient environments. Interpretation of δ18OSO4 records has been complicated by rapid oxygen isotope equilibration between sulfoxyanions and water. Specifically, the apparent relationship that develops between δ18OSO4 and δ18Owater during microbial sulfate reduction is thought to result from rapid oxygen isotope equilibrium between intracellular water and aqueous sulfite - a reactive intermediate of the sulfate reduction network that can back-react to produce sulfate. Here, we describe the oxygen equilibrium isotope effect between water and sulfite (referring to all the sum of all S(IV)-oxyanions including sulfite and both isomers and the dimer of bisulfite). Based on experiments conducted over a range of pH (4.5-9.8) and temperature (2-95 °C), where ε = 1000 * (α - 1), we find εSO3-H2O=13.61-0.299∗pH-0.081∗T °C. Thus, at a pH (7.0) and temperature (25 °C) typifying commonly used experimental conditions for sulfate reducing bacterial cultures, sulfite is enriched in 18O by 9.5‰ (±0.8‰) relative to ambient water. We examine the implication of these results in a sulfate reduction network that has been revised to reflect our understanding of the reactions involving oxygen. By evaluating previously published data within this new architecture, our results are consistent with previous suggestions of high reversibility of the sulfate reduction biochemical network. We also demonstrate that intracellular exchange rates between SO32- and water must be on average 1-3 orders of magnitude more rapid than intracellular fluxes of sulfate reduction intermediates and that kinetic isotope effects upstream of SO32- are required to explain previous laboratory and environmental studies of δ18OSO4 resulting as a consequence of sulfate reduction.

  5. Kinetic Results for Mutations of Conserved Residues H304 and R309 of Human Sulfite Oxidase Point to Mechanistic Complexities

    PubMed Central

    Davis, Amanda C.; Johnson-Winters, Kayunta; Arnold, Anna R.; Tollin, Gordon; Enemark, John H.

    2014-01-01

    Several point mutations in the gene of human sulfite oxidase (hSO) result in isolated sulfite oxidase deficiency, an inherited metabolic disorder. Three conserved residues (H304, R309, K322) are hydrogen bonded to the phosphate group of the molybdenum cofactor, and the R309H and K322R mutations are responsible for isolated sulfite oxidase deficiency. The kinetic effects of the K322R mutation have been previously reported (Rajapakshe et al. 2012, Chem. Biodiversity 9, 1621-1634); here we investigate several mutants of H304 and R309 by steady-state kinetics, laser flash photolysis studies of intramolecular electron transfer (IET), and spectroelectrochemistry. An unexpected result is that all of the mutants show decreased rates of IET but increased steady-state rates of catalysis. However, in all cases the rate of IET is greater than the overall turnover rate, showing that IET is not the rate determining step for any of the mutations. PMID:24968320

  6. Multicopy Fzf1 (Sul1) Suppresses the Sulfite Sensitivity but Not the Glucose Derepression or Aberrant Cell Morphology of a Grr1 Mutant of Saccharomyces Cerevisiae

    PubMed Central

    Avram, D.; Bakalinsky, A. T.

    1996-01-01

    An ssu2 mutation in Sacccharomyces cerevisiae, previously shown to cause sulfite sensitivity, was found to be allelic to GRR1, a gene previously implicated in glucose repression. The suppressor rgt1, which suppresses the growth defects of grr1 strains on glucose, did not fully suppress the sensitivity on glucose or nonglucose carbon sources, indicating that it is not strictly linked to a defect in glucose metabolism. Because the Cln1 protein was previously shown to be elevated in grr1 mutants, the effect of CLN1 overexpression on sulfite sensitivity was investigated. Overexpression in GRR1 cells resulted in sulfite sensitivity, suggesting a connection between CLN1 and sulfite metabolism. Multicopy FZF1, a putative transcription factor, was found to suppress the sulfite sensitive phenotype of grr1 strains, but not the glucose derepression or aberrant cell morphology. Multicopy FZF1 was also found to suppress the sensitivity of a number of other unrelated sulfite-sensitive mutants, but not that of ssu1 or met20, implying that FZF1 may act through Ssu1p and Met20p. Disruption of FZF1 resulted in sulfite sensitivity when the construct was introduced in single copy at the FZF1 locus in a GRR1 strain, providing evidence that FZF1 is involved in sulfite metabolism. PMID:8889516

  7. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sulfite to form the sulfite addition products and liberate sodium hydroxide (NaOH); however, at room temperature, the methanol groups present will also react to liberate NaOH. Titrate at 0 degrees Celsius ( °C... g methanol). 2.2.5Sodium chloride (NaCl) (reagent grade). 2.2.6Sodium hydroxide (NaOH)....

  8. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... with sodium sulfite to form the sulfite addition products and liberate sodium hydroxide (NaOH); however, at room temperature, the methanol groups present will also react to liberate NaOH. Titrate at 0... hydroxide (NaOH). 2.3Procedure. 2.3.1Prepare sufficient quantity of crushed ice for three...

  9. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with sodium sulfite to form the sulfite addition products and liberate sodium hydroxide (NaOH); however, at room temperature, the methanol groups present will also react to liberate NaOH. Titrate at 0... hydroxide (NaOH). 2.3Procedure. 2.3.1Prepare sufficient quantity of crushed ice for three...

  10. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... with sodium sulfite to form the sulfite addition products and liberate sodium hydroxide (NaOH); however, at room temperature, the methanol groups present will also react to liberate NaOH. Titrate at 0... hydroxide (NaOH). 2.3Procedure. 2.3.1Prepare sufficient quantity of crushed ice for three...

  11. Quaternary liquid/liquid equilibria of sodium sulfate, sodium sulfite and water with two solvents: Acetone and 2-propanol

    SciTech Connect

    Schiozer, A.L.

    1994-03-01

    Aqueous solutions of sodium sulfate and sodium sulfite are produced from sodium carbonate in flue-gas scrubbers; recovery of these salts often requires multi-effect evaporators; however, a new energy-efficient unit operation called extractive crystallization has been shown to have reduced energy costs. In this process, an organic solvent is added to the aqueous salt solution to precipitate salt. Acetone is a suitable solvent for this process, better than 2-propanol. Liquid/liquid/solid equilibria for ternary systems containing a salt, water, and an organic solvent were measured. Systems investigated were sodium sulfite/water/acetone and sodium sulfite/water/2-propanol. Experiments were conducted at salt saturation covering a temperature range between the lower consolute temperature and 48.6{degrees}C. In the attempt to improve the extractive crystallization process for recovery of sodium sulfate from flue-gas scrubbers, attention was given to a feed containing a mixture of sodium sulfite and sodium sulfate. Liquid-liquid equilibria for quaternary systems containing two salts, water, and an organic solvent were experimentally determined at 35{degrees}C. The systems investigated were sodium sulfate/sodium sulfite/water/acetone and sodium sulfate/sodium sulfite/water/2propanol. The systems were studied at three salt ratios. For each salt ratio, experiments were conducted starting at saturation, water was then added until the one-phase region was reached. Mixtures of the two salts proved to have a small disadvantage relative to the 100 % sulfate feed process. Therefore, a sulfate-based extractive crystallization process is recommended.

  12. Rapidly responsive and highly selective fluorescent probe for sulfite detection in real samples and living cells.

    PubMed

    Li, Hongda

    2015-10-15

    Sulfites (HSO3(-) or SO3(-)) have very significant toxicity in the environment and in the system. However, developing specific identification of sulfite probes is still very important. In this paper, a highly selective colorimetric and fluorescent probe (HHC) was synthesized to detect HSO3(-) in real samples and living cells. Sensing performance and preponderance are listed as follows. First, probe HHC showed remarkable selectivity for HSO3(-) over varieties of other species, including cysteine, glutathione, S(2-), CN(-), and reactive oxygen species, mainly because of the introduction of the electron-poor C=C double bond for HSO3(-). Second, probe HHC has great molar absorptivity, allowing it to act as a visual detection of probe for HSO3(-). Third, the fluorescence intensities of HHC linearly correlate with the concentration of HSO3(-), with a detection limit of 6.8 nm. Finally, our proposed probe can be applied to the visually determination of trace HSO3(-) in real samples and living HeLa cells with high precision. We hope that our proposed probe will greatly benefit biological sciences when biological researchers survey the role of HSO3(-) in biological systems. PMID:26515011

  13. Redox states of Desulfovibrio vulgaris DsrC, a key protein in dissimilatory sulfite reduction

    SciTech Connect

    Venceslau, Sofia S.; Cort, John R.; Baker, Erin S.; Chu, Rosalie K.; Robinson, Errol W.; Dahl, Christiane; Saraiva, Lígia M.; Pereira, Inês A.C.

    2013-11-29

    Highlights: •DsrC is known to interact with the dissimilatory sulfite reductase enzyme (DsrAB). •We show that, however, most cellular DsrC is not associated with DsrAB. •A gel-shift assay was developed that allows monitoring of the DsrC redox state. •The DsrC intramolecularly oxidized state could only be produced by arginine treatment. -- Abstract: Dissimilatory reduction of sulfite is carried out by the siroheme enzyme DsrAB, with the involvement of the protein DsrC, which has two conserved redox-active cysteines. DsrC was initially believed to be a third subunit of DsrAB. Here, we report a study of the distribution of DsrC in cell extracts to show that, in the model sulfate reducer Desulfovibrio vulgaris, the majority of DsrC is not associated with DsrAB and is thus free to interact with other proteins. In addition, we developed a cysteine-labelling gel-shift assay to monitor the DsrC redox state and behaviour, and procedures to produce the different redox forms. The oxidized state of DsrC with an intramolecular disulfide bond, which is proposed to be a key metabolic intermediate, could be successfully produced for the first time by treatment with arginine.

  14. A novel sulfite alternative scavenger and benefits for the use of traced oxygen scavengers

    SciTech Connect

    Batton, C.B.; Riede, R.F.

    1994-12-31

    Dissolved oxygen in boiler systems is known to cause corrosion. Mechanical deaeration removes the majority of the dissolved oxygen while oxygen scavengers remove the remaining trace level. Sodium sulfate is a commonly used scavenger, but has several use limitations, such as high solids contribution to boiler water and decomposition products that are corrosive gases which can cause downstream equipment problems. A novel sulfite replacement oxygen scavenger has been developed which addresses the limitations of sulfite. Identification and demonstrated performance of the new scavenger is presented using both research and field data. In addition to oxygen scavenger performance, the success of a boiler water treatment program is dependent upon the correct dosage added to the feedwater. Plant managers and operators often struggle with indirect or inaccurate methods to determine what is occurring within their system. An oxygen scavenger product containing a proprietary fluorescent tracer has been developed. This technology for boilers provides a breakthrough in measurement capability for monitoring the dynamics of a boiler system. These two oxygen scavenger developments represent the result of maintaining desirable performance characteristics and significantly improving current technology. Laboratory and field data supporting these results are presented.

  15. Divergence of the yeast transcription factor FZF1 affects sulfite resistance.

    PubMed

    Engle, Elizabeth K; Fay, Justin C

    2012-01-01

    Changes in gene expression are commonly observed during evolution. However, the phenotypic consequences of expression divergence are frequently unknown and difficult to measure. Transcriptional regulators provide a mechanism by which phenotypic divergence can occur through multiple, coordinated changes in gene expression during development or in response to environmental changes. Yet, some changes in transcriptional regulators may be constrained by their pleiotropic effects on gene expression. Here, we use a genome-wide screen for promoters that are likely to have diverged in function and identify a yeast transcription factor, FZF1, that has evolved substantial differences in its ability to confer resistance to sulfites. Chimeric alleles from four Saccharomyces species show that divergence in FZF1 activity is due to changes in both its coding and upstream noncoding sequence. Between the two closest species, noncoding changes affect the expression of FZF1, whereas coding changes affect the expression of SSU1, a sulfite efflux pump activated by FZF1. Both coding and noncoding changes also affect the expression of many other genes. Our results show how divergence in the coding and promoter region of a transcription factor alters the response to an environmental stress.

  16. Concentration of simple aldehydes by sulfite-containing double-layer hydroxide minerals: implications for biopoesis

    NASA Technical Reports Server (NTRS)

    Pitsch, S.; Krishnamurthy, R.; Arrhenius, G.; Bada, J. L. (Principal Investigator)

    2000-01-01

    Environmental conditions play an important role in conceptual studies of prebiotically relevant chemical reactions that could have led to functional biomolecules. The necessary source compounds are likely to have been present in dilute solution, raising the question of how to achieve selective concentration and to reach activation. With the assumption of an initial 'RNA World', the questions of production, concentration, and interaction of aldehydes and aldehyde phosphates, potential precursors of sugar phosphates, come into the foreground. As a possible concentration process for simple, uncharged aldehydes, we investigated their adduct formation with sulfite ion bound in the interlayer of positively charged expanding-sheet-structure double-layer hydroxide minerals. Minerals of this type, initially with chloride as interlayer counter anion, have previously been shown to induce concentration and subsequent aldolization of aldehyde phosphates to form tetrose, pentose, and hexose phosphates. The reversible uptake of the simple aldehydes formaldehyde, glycolaldehyde, and glyceraldehyde by adduct formation with the immobilized sulfite ions is characterized by equilibrium constants of K=1.5, 9, and 11, respectively. This translates into an observable uptake at concentrations exceeding 50 mM.

  17. Rapidly responsive and highly selective fluorescent probe for sulfite detection in real samples and living cells.

    PubMed

    Li, Hongda

    2015-10-15

    Sulfites (HSO3(-) or SO3(-)) have very significant toxicity in the environment and in the system. However, developing specific identification of sulfite probes is still very important. In this paper, a highly selective colorimetric and fluorescent probe (HHC) was synthesized to detect HSO3(-) in real samples and living cells. Sensing performance and preponderance are listed as follows. First, probe HHC showed remarkable selectivity for HSO3(-) over varieties of other species, including cysteine, glutathione, S(2-), CN(-), and reactive oxygen species, mainly because of the introduction of the electron-poor C=C double bond for HSO3(-). Second, probe HHC has great molar absorptivity, allowing it to act as a visual detection of probe for HSO3(-). Third, the fluorescence intensities of HHC linearly correlate with the concentration of HSO3(-), with a detection limit of 6.8 nm. Finally, our proposed probe can be applied to the visually determination of trace HSO3(-) in real samples and living HeLa cells with high precision. We hope that our proposed probe will greatly benefit biological sciences when biological researchers survey the role of HSO3(-) in biological systems.

  18. Kinetic and structural studies reveal a unique binding mode of sulfite to the nickel center in urease.

    PubMed

    Mazzei, Luca; Cianci, Michele; Benini, Stefano; Bertini, Leonardo; Musiani, Francesco; Ciurli, Stefano

    2016-01-01

    Urease is the most efficient enzyme known to date, and catalyzes the hydrolysis of urea using two Ni(II) ions in the active site. Urease is a virulence factor in several human pathogens, while causing severe environmental and agronomic problems. Sporosarcina pasteurii urease has been used extensively in the structural characterization of the enzyme. Sodium sulfite has been widely used as a preservative in urease solutions to prevent oxygen-induced oxidation, but its role as an inhibitor has also been suggested. In the present study, isothermal titration microcalorimetry was used to establish sulfite as a competitive inhibitor for S. pasteurii urease, with an inhibition constant of 0.19mM at pH7. The structure of the urease-sulfite complex, determined at 1.65Å resolution, shows the inhibitor bound to the dinuclear Ni(II) center of urease in a tridentate mode involving bonds between the two Ni(II) ions in the active site and all three oxygen atoms of the inhibitor, supporting the observed competitive inhibition kinetics. This coordination mode of sulfite has never been observed, either in proteins or in small molecule complexes, and could inspire synthetic coordination chemists as well as biochemists to develop urease inhibitors based on this chemical moiety. PMID:26580226

  19. Genotypic variation in sulfur assimilation and metabolism of onion (Allium cepa L.) III. Characterization of sulfite reductase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic and cDNA sequences corresponding to a ferredoxin-sulfite reductase (SiR) have been cloned from bulb onion (Allium cepa L.) and the expression of the gene and activity of the enzyme characterised with respect to sulfur (S) supply. Cloning, mapping and expression studies revealed that onion ha...

  20. Kinetic and structural studies reveal a unique binding mode of sulfite to the nickel center in urease.

    PubMed

    Mazzei, Luca; Cianci, Michele; Benini, Stefano; Bertini, Leonardo; Musiani, Francesco; Ciurli, Stefano

    2016-01-01

    Urease is the most efficient enzyme known to date, and catalyzes the hydrolysis of urea using two Ni(II) ions in the active site. Urease is a virulence factor in several human pathogens, while causing severe environmental and agronomic problems. Sporosarcina pasteurii urease has been used extensively in the structural characterization of the enzyme. Sodium sulfite has been widely used as a preservative in urease solutions to prevent oxygen-induced oxidation, but its role as an inhibitor has also been suggested. In the present study, isothermal titration microcalorimetry was used to establish sulfite as a competitive inhibitor for S. pasteurii urease, with an inhibition constant of 0.19mM at pH7. The structure of the urease-sulfite complex, determined at 1.65Å resolution, shows the inhibitor bound to the dinuclear Ni(II) center of urease in a tridentate mode involving bonds between the two Ni(II) ions in the active site and all three oxygen atoms of the inhibitor, supporting the observed competitive inhibition kinetics. This coordination mode of sulfite has never been observed, either in proteins or in small molecule complexes, and could inspire synthetic coordination chemists as well as biochemists to develop urease inhibitors based on this chemical moiety.

  1. Bisulfite and sulfite as derivatives of sulfur dioxide alters biomechanical behaviors of airway smooth muscle cells in culture.

    PubMed

    Song, Aijing; Lin, Feng; Li, Jianming; Liao, Qingfeng; Liu, Enmei; Jiang, Xuemei; Deng, Linhong

    2014-02-01

    Sulfur dioxide (SO2) is a common air pollutant that triggers asthmatic symptoms, but its toxicological mechanisms are not fully understood. Specifically, it is unclear how SO2 in vivo affects airway smooth muscle (ASM) cells of which the mechanics is known to ultimately mediate airway hyperresponsiveness (AHR) - a hallmark feature of asthma. To this end, we investigated the effects of bisulfite/sulfite (1:3 M/M in neutral fluid to simulate the in vivo derivatives of inhaled SO2 in the airways), on the viability, migration, stiffness and contractility of ASM cells cultured in vitro. The results showed that bisulfite/sulfite consistently increased viability, migration, F-actin intensity and stiffness of ASM cells in similar fashion as concentration increasing from 10(-4) to 10(-1) mmol/L. However, bisulfite/sulfite increased the ASM cell contractility induced by KCl only at the concentration between 10(-4) and 10(-3) mmol/L (p < 0.05), while having no consistent effect on that induced by histamine. At the concentration of 10(0) mmol/L, bisulfite/sulfite became acutely toxic to the ASM cells. Taken together, the data suggest that SO2 derivatives at low levels in vivo may directly increase the mass, stiffness and contractility of ASM cells, which may help understand the mechanism in which specific air pollutants contribute in vivo to the pathogenesis of asthma.

  2. Oxidation of ammonium sulfite by a multi-needle-to-plate gas phase pulsed corona discharge reactor

    NASA Astrophysics Data System (ADS)

    Ren, Hua; Lu, Na; Shang, Kefeng; Li, Jie; Wu, Yan

    2013-03-01

    The oxidation of ammonium sulfite in the ammonia-based flue gas desulfurization (FGD) process was investigated in a multi-needle-to-plate gas phase pulsed corona discharge reactor in this paper. The effect of several parameters, including capacitance and peak pulse voltage of discharge system, electrode gap and bubbling gas flow rate on the oxidation rate of ammonium sulfite was reviewed. The oxidation rate of ammonium sulfite could reach 47.2% at the capacitance, the peak pulse voltage, electrode gap and bubbling gas flow rate equal to 2 nF, -24.6 k V, 35 mm and 4 L min-1 within treatment time of 40 min The experimental results indicate that the gas phase pulsed discharge system with a multi-needle-to-plate electrode can oxide the ammonium sulfite. The oxidation rate increased with the applied capacitance and peak pulse voltage and decreased with the electrode gap. As the bubbling gas flow rate increased, the oxidation rate increased first and then tended to reach a stationary value. These results would be important for the process optimization of the (NH4)2SO3 to (NH4)2SO4 oxidation.

  3. Fed-batch cultivation of the marine bacterium Sulfitobacter pontiacus using immobilized substrate and purification of sulfite oxidase by application of membrane adsorber technology.

    PubMed

    Muffler, Kai; Ulber, Roland

    2008-03-01

    Sulfitobacter pontiacus, a gram-negative heterotrophic bacterium isolated from the Black Sea is well known to produce a soluble AMP-independent sulfite oxidase (sulfite: acceptor oxidoreductase) of high activity. Such an enzyme can be of great help in establishing biosensor systems for detection of sulfite in food and beverages considering the high sensitivity of biosensors and the increasing demand for such biosensor devices. For obtaining efficient amounts of the enzyme, an induction of its biosynthesis by supplementing sufficient concentrations of sodium sulfite to the fermentation broth is required. Owing to the fact that a high initial concentration of sodium sulfite decreases dramatically the enzyme expression, different fed-batch strategies can be applied to circumvent such inhibition or repression of the enzyme respectively. By the use of sulfite species immobilized in polyvinyl alcohol gels, an approach to the controlled and continuous feeding of sulfite to the cultivation media could be established to diminish inhibitory concentrations. Furthermore, the purification of the enzyme is described by using membrane adsorber technology.

  4. Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

    PubMed

    Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

    2015-02-01

    A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour.

  5. Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

    PubMed

    Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

    2015-02-01

    A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour. PMID:25435239

  6. Sulfur X-Ray Absorption And Vibrational Spectroscopic Study of Sulfur Dioxide, Sulfite, And Sulfonate Solutions And of the Substituted Sulfonate Ions X(3)CSO(3-)(X = H, Cl, F)

    SciTech Connect

    Risberg, E.Damian; Eriksson, L.; Mink, J.; Pettersson, L.G.M.; Skripkin, M.Yu.; Sandstrom, M.

    2009-06-02

    Sulfur K-edge X-ray absorption near-edge structure (XANES) spectra have been recorded and the S(1s) electron excitations evaluated by means of density functional theory-transition potential (DFT-TP) calculations to provide insight into the coordination, bonding, and electronic structure. The XANES spectra for the various species in sulfur dioxide and aqueous sodium sulfite solutions show considerable differences at different pH values in the environmentally important sulfite(IV) system. In strongly acidic (pH < {approx}1) aqueous sulfite solution the XANES spectra confirm that the hydrated sulfur dioxide molecule, SO{sub 2}(aq), dominates. The theoretical spectra are consistent with an OSO angle of {approx}119{sup o} in gas phase and acetonitrile solution, while in aqueous solution hydrogen bonding reduces the angle to {approx}116{sup o}. The hydration affects the XANES spectra also for the sulfite ion, SO{sub 3}{sup 2-}. At intermediate pH (4) the two coordination isomers, the sulfonate (HSO{sub 3{sup -}}) and hydrogen sulfite (SO{sub 3}H{sup -}) ions with the hydrogen atom coordinated to sulfur and oxygen, respectively, could be distinguished with the ratio HSO{sub 3{sup -}}:SO{sub 3}H{sup -} about 0.28:0.72 at 298 K. The relative amount of HSO{sub 3{sup -}} increased with increasing temperature in the investigated range from 275 to 343 K. XANES spectra of sulfonate, methanesulfonate, trichloromethanesulfonate, and trifluoromethanesulfonate compounds, all with closely similar S-O bond distances in tetrahedral configuration around the sulfur atom, were interpreted by DFT-TP computations. The energy of their main electronic transition from the sulfur K-shell is about 2478 eV. The additional absorption features are similar when a hydrogen atom or an electron-donating methyl group is bonded to the -SO{sub 3} group. Significant changes occur for the electronegative trichloromethyl (Cl{sub 3}C-) and trifluoromethyl (F{sub 3}C-) groups, which strongly affect the

  7. Sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust enzymatic saccharification of hardwoods.

    PubMed

    Wang, G S; Pan, X J; Zhu, J Y; Gleisner, R; Rockwood, D

    2009-01-01

    This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180 degrees C, SPORL can achieve near-complete cellulose conversion to glucose in a wide range of pretreatment liquor of pH 2.0-4.5 in only about 10 h enzymatic hydrolysis. The enzyme loading was about 20 FPU cellulase plus 30 CBU beta-glucosidase per gram of cellulose. The production of fermentation inhibitor furfural was less than 20 mg/g of aspen wood at pH 4.5. With pH 4.5, SPORL avoided reactor corrosion problem and eliminated the need for substrate neutralization prior to enzymatic hydrolysis. Similar results were obtained from maple and eucalyptus.

  8. Redox states of Desulfovibrio vulgaris DsrC, a key protein in dissimilatory sulfite reduction

    SciTech Connect

    Venceslau, Sofia S.; Cort, John R.; Baker, Erin Shammel; Chu, Rosalie K.; Robinson, Errol W.; Dahl, Christiane; Saraiva, Ligia M.; Pereira, Ines Ac

    2013-11-29

    Dissimilatory reduction of sulfite is carried out by the siroheme enzyme DsrAB, with the involvement of the protein DsrC having two conserved cysteine residues. Here, we report a study of the distribution of DsrC in cell extracts, a cysteine-labelling gel-shift assay to monitor its redox state and behaviour, and procedures to produce the different redox forms. We show that, in the model sulfate reducer Desulfovibrio vulgaris, the majority of DsrC is not associated with DsrAB and is thus free to interact with other proteins. In addition, we successfully produced DsrC with an intramolecular disulfide bond (oxidized state) by treatment with arginine.

  9. Peroxisomal localization of sulfite oxidase separates it from chloroplast-based sulfur assimilation.

    PubMed

    Nowak, Katharina; Luniak, Nora; Witt, Christina; Wüstefeld, Yvonne; Wachter, Andreas; Mendel, Ralf R; Hänsch, Robert

    2004-12-01

    Recently, we isolated the sulfite oxidase (SO) gene from Arabidopsis thaliana and characterized the purified SO protein. The purpose of the present study was to determine the subcellular localization of this novel plant enzyme. Immunogold electron-microscopic analysis showed the gold labels nearly exclusively in the peroxisomes. To verify this finding, green fluorescent protein was fused to full-length plant SO including the putative peroxisomal targeting signal 1 (PTS1) 'SNL' and expressed in tobacco leaves. Our results showed a punctate fluorescence pattern resembling that of peroxisomes. Co-labelling with MitoTracker-Red excluded that the observed fluorescence was due to mitochondrial sorting. By investigation of deleted or mutated PTS1, no functional peroxisomal targeting signal 2 (PTS2) could be detected in plant SO. This conclusion is supported by expression studies in Pichia pastoris mutants with defined defects either in PTS1- or PTS2-mediated peroxisomal import. PMID:15653809

  10. Mimic of superoxide dismutase activity protects Chlorella sorokiniana against the toxicity of sulfite

    SciTech Connect

    Rabinowitch, H.D.; Rosen, G.M.; Fridovich, I.

    1989-01-01

    The spin-trapping agent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) has been used to demonstrate the light-dependent production of O/sub 2/- by Chlorella sorokiniana. In the presence of SO/sub 3/= a light-dependent production of the sulfur trioxy anion radical (SO/sub 3/-.) could also be seen. A complex prepared by reacting desferrioxamine with MnO/sub 2/, which catalyzes the dismutation of O/sub 2/-, protected the alga against the toxicity of sulfite. The data suggest that SO/sub 2/ toxicity is at least partially due to the effects of sulfoxy-free radicals generated by the oxidation of SO3= by O/sub 2/-.

  11. Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration.

    PubMed

    Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

    2015-01-01

    Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively. PMID:26729180

  12. Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration

    PubMed Central

    Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

    2015-01-01

    Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively. PMID:26729180

  13. Determination of free sulfites (SO3-2) in dried fruits processed with sulfur dioxide by ion chromatography through anion exchange column and conductivity detection.

    PubMed

    Liao, Benjamin S; Sram, Jacqueline C; Files, Darin J

    2013-01-01

    A simple and effective anion ion chromatography (IC) method with anion exchange column and conductivity detector has been developed to determine free sulfites (SO3-2) in dried fruits processed with sulfur dioxide. No oxidation agent, such as hydrogen peroxide, is used to convert sulfites to sulfates for IC analysis. In addition, no stabilizing agent, such as formaldehyde, fructose or EDTA, is required during the sample extraction. This method uses aqueous 0.2 N NaOH as the solvent for standard preparation and sample extraction. The sulfites, either prepared from standard sodium sulfite powder or extracted from food samples, are presumed to be unbound SO3-2 in aqueous 0.2 N NaOH (pH > 13), because the bound sulfites in the sample matrix are released at pH > 10. In this study, sulfites in the standard solutions were stable at room temperature (i.e., 15-25 degrees C) for up to 12 days. The lowest standard of the linear calibration curve is set at 1.59 microg/mL SO3-2 (equivalent to 6.36 microg/g sample with no dilution) for analysis of processed dried fruits that would contain high levels (>1000 microg/g) of sulfites. As a consequence, this method typically requires significant dilution of the sample extract. Samples are prepared with a simple procedure of sample compositing, extraction with aqueous 0.2 N NaOH, centrifugation, dilution as needed, and filtration prior to IC. The sulfites in these sample extracts are stable at room temperature for up to 20 h. Using anion IC, the sulfites are eluted under isocratic conditions with 10 mM aqueous sodium carbonate solution as the mobile phase passing through an anion exchange column. The sulfites are easily separated, with an analysis run time of 18 min, regardless of the dried fruit matrix. Recoveries from samples spiked with sodium sulfites were demonstrated to be between 81 and 105% for five different fruit matrixes (apricot, golden grape, white peach, fig, and mango). Overall, this method is simple to perform and

  14. Determination of free sulfites (SO3-2) in dried fruits processed with sulfur dioxide by ion chromatography through anion exchange column and conductivity detection.

    PubMed

    Liao, Benjamin S; Sram, Jacqueline C; Files, Darin J

    2013-01-01

    A simple and effective anion ion chromatography (IC) method with anion exchange column and conductivity detector has been developed to determine free sulfites (SO3-2) in dried fruits processed with sulfur dioxide. No oxidation agent, such as hydrogen peroxide, is used to convert sulfites to sulfates for IC analysis. In addition, no stabilizing agent, such as formaldehyde, fructose or EDTA, is required during the sample extraction. This method uses aqueous 0.2 N NaOH as the solvent for standard preparation and sample extraction. The sulfites, either prepared from standard sodium sulfite powder or extracted from food samples, are presumed to be unbound SO3-2 in aqueous 0.2 N NaOH (pH > 13), because the bound sulfites in the sample matrix are released at pH > 10. In this study, sulfites in the standard solutions were stable at room temperature (i.e., 15-25 degrees C) for up to 12 days. The lowest standard of the linear calibration curve is set at 1.59 microg/mL SO3-2 (equivalent to 6.36 microg/g sample with no dilution) for analysis of processed dried fruits that would contain high levels (>1000 microg/g) of sulfites. As a consequence, this method typically requires significant dilution of the sample extract. Samples are prepared with a simple procedure of sample compositing, extraction with aqueous 0.2 N NaOH, centrifugation, dilution as needed, and filtration prior to IC. The sulfites in these sample extracts are stable at room temperature for up to 20 h. Using anion IC, the sulfites are eluted under isocratic conditions with 10 mM aqueous sodium carbonate solution as the mobile phase passing through an anion exchange column. The sulfites are easily separated, with an analysis run time of 18 min, regardless of the dried fruit matrix. Recoveries from samples spiked with sodium sulfites were demonstrated to be between 81 and 105% for five different fruit matrixes (apricot, golden grape, white peach, fig, and mango). Overall, this method is simple to perform and

  15. Influence of Cu(II) on the interaction between sulfite and horseradish peroxidase in vitro

    NASA Astrophysics Data System (ADS)

    Lan, Jie; Guo, Dong-Sheng; Yuan, Xiao-Ying

    2007-06-01

    This paper discussed the quantitative influence of Cu(II) on the interaction between horseradish peroxidase (HRP) and sulfite (SO 32-), which is a derivate of sulfite dioxide in human bodies, by using fluorescence spectrum and ultraviolet (UV) absorption spectrometry in vitro. The results show that under the conditions of physiological pH and room-temperature, Cu(II) can bind strongly with both the protein part and the ferroporphyrin part in HRP at a low concentration (10 -4 mol L -1), and the combination constants are 2.047 × 10 3 and 7.66 × 10 2 L mol -1, respectively. Under the same conditions, SO 32- at low concentrations (<0.15 mol L -1) has little quenching for the fluorescence of HRP at 330 nm, and the combination constant is 0.108 L mol -1. While the fluorescence intensity at 440 nm enhance gradually with the increased concentration of SO 32- (<0.1 mol L -1), and the combination constant is 8.219 L mol -1. These indicate that SO 32- at low concentration has little reaction with the enzyme protein part in HRP but obvious reaction with the ferroporphyrin part in HRP. After SO 32- at low concentrations is added into the HRP-Cu(II) binary system, the reaction constants between SO 32- and the enzyme protein part in HRP increase rapidly. Compared with the absence of Cu(II), the combination constant of SO 32- with the enzyme protein part in HRP increases nearly 70 times with a certain Cu(II) concentration (5.0 × 10 -4 mol L -1) in the system. However, the presence of Cu(II) in the system has little effect on the reaction constants between SO 32- and the ferroporphyrin part in HRP.

  16. Pulsed EPR Spectroscopy of 33S-Labeled Molybdenum Cofactor in Catalytically Active Bioengineered Sulfite Oxidase

    PubMed Central

    Klein, Eric L.; Belaidi, Abdel Ali; Raitsimring, Arnold M.; Davis, Amanda C.; Krämer, Tobias; Astashkin, Andrei V.; Neese, Frank; Schwarz, Günter; Enemark, John H.

    2014-01-01

    Molybdenum enzymes contain at least one pyranopterin dithiolate (molybdopterin, MPT) moiety that coordinates Mo through two dithiolate (dithiolene) sulfur atoms. For sulfite oxidase (SO), hyperfine interactions (hfi) and nuclear quadrupole interactions (nqi) of magnetic nuclei (I ≠ 0) near the Mo(V) (d1) center have been measured using high-resolution pulsed electron paramagnetic resonance (EPR) methods and interpreted with the help of the density functional theory (DFT) calculations. These have provided important insights about the active site structure and the reaction mechanism of the enzyme. However, it has not been possible to use EPR to probe the dithiolene sulfurs directly since naturally abundant 32S has no nuclear spin (I = 0). Here we describe direct incorporation of 33S (I = 3/2), the only stable magnetic sulfur isotope, into MPT using controlled in vitro synthesis with purified proteins. The electron spin echo envelope modulation (ESEEM) spectra from 33S-labeled MPT in this catalytically active SO variant are dominated by the ‘inter-doublet’ transition arising from the strong nuclear quadrupole interaction, as also occurs for the 33S-labeled exchangeable equatorial sulfite ligand [Klein, E. L., et al., Inorg. Chem. 2012, 51, 1408 – 1418]. The estimated experimental hfi and nqi parameters for 33S (aiso = 3 MHz and e2Qq/h = 25 MHz) are in good agreement with those predicted by DFT. In addition, the DFT calculations show that the two 33S atoms are indistinguishable by EPR and reveal a strong intermixing between their out-of-plane pz orbitals and the dxy orbital of Mo(V). PMID:24387640

  17. Comparative Study of SPORL and Dilute Acid Pretreatments of Spruce for Cellulosic Ethanol Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The performance of two pretreatment methods, Sulfite Pretreatment to Overcome Recalcitrance of Lignocellulose (SPORL) and Dilute Acid (DA), was compared in pretreating softwood (spruce) for fuel ethanol production under the same conditions of temperature (180°C), time (30 min), sulfuric acid loading...

  18. Antioxidative Mechanisms of Sulfite and Protein-Derived Thiols during Early Stages of Metal Induced Oxidative Reactions in Beer.

    PubMed

    Lund, Marianne N; Krämer, Anna C; Andersen, Mogens L

    2015-09-23

    The radical-mediated reactions occurring during the early stages of beer storage were studied by following the rate of oxygen consumption, radical formation as detected by electron spin resonance spectroscopy, and concentrations of the antioxidant compounds sulfite and thiols. Addition of either Fe(III) or Fe(II) had similar effects, indicating that a fast redox equilibrium is obtained between the two species in beer. Addition of iron in combination with hydrogen peroxide gave the most pronounced levels of oxidation due to a direct initiation of ethanol oxidation through generation of hydroxyl radicals by the Fenton reaction. The concentration of sulfite decreased more than the thiol concentration, suggesting that thiols play a secondary role as antioxidants by mainly quenching 1-hydroxyethyl radicals that are intermediates in the oxidation of ethanol. Increasing the temperature had a minor effect on the rate of oxygen consumption.

  19. Targeted knock-out of a gene encoding sulfite reductase in the moss Physcomitrella patens affects gametophytic and sporophytic development.

    PubMed

    Wiedemann, Gertrud; Hermsen, Corinna; Melzer, Michael; Büttner-Mainik, Annette; Rennenberg, Heinz; Reski, Ralf; Kopriva, Stanislav

    2010-06-01

    A key step in sulfate assimilation into cysteine is the reduction of sulfite to sulfide by sulfite reductase (SiR). This enzyme is encoded by three genes in the moss Physcomitrella patens. To obtain a first insight into the roles of the individual isoforms, we deleted the gene encoding the SiR1 isoform in P. patens by homologous recombination and subsequently analysed the DeltaSiR1 mutants. While DeltaSiR1 mutants showed no obvious alteration in sulfur metabolism, their regeneration from protoplasts and their ability to produce mature spores was significantly affected, highlighting an unexpected link between moss sulfate assimilation and development, that is yet to be characterized.

  20. Isotope effects associated with the anaerobic oxidation of sulfite and thiosulfate by the photosynthetic bacterium, Chromatium vinosum

    NASA Technical Reports Server (NTRS)

    Fry, B.; Gest, H.; Hayes, J. M.

    1985-01-01

    The purple photosynthetic bacterium Chromatium vinosum, strain D, catalyzes several oxidations of reduced sulfur compounds under anaerobic conditions in the light: e.g., sulfide --> sulfur --> sulfate, sulfite --> sulfate, and thiosulfate --> sulfur + sulfate. Here it is shown that no sulfur isotope effect is associated with the last of these processes; isotopic compositions of the sulfur and sulfate produced can differ, however, if the sulfane and sulfonate positions within the thiosulfate have different isotopic compositions. In the second process, an observed change from an inverse to a normal isotope effect during oxidation of sulfite may indicate the operation of 2 enzymatic pathways. In contrast to heterotrophic anaerobic reduction of oxidized sulfur compounds, anaerobic oxidations of inorganic sulfur compounds by photosynthetic bacteria are characterized by relatively small isotope effects.

  1. Antioxidative Mechanisms of Sulfite and Protein-Derived Thiols during Early Stages of Metal Induced Oxidative Reactions in Beer.

    PubMed

    Lund, Marianne N; Krämer, Anna C; Andersen, Mogens L

    2015-09-23

    The radical-mediated reactions occurring during the early stages of beer storage were studied by following the rate of oxygen consumption, radical formation as detected by electron spin resonance spectroscopy, and concentrations of the antioxidant compounds sulfite and thiols. Addition of either Fe(III) or Fe(II) had similar effects, indicating that a fast redox equilibrium is obtained between the two species in beer. Addition of iron in combination with hydrogen peroxide gave the most pronounced levels of oxidation due to a direct initiation of ethanol oxidation through generation of hydroxyl radicals by the Fenton reaction. The concentration of sulfite decreased more than the thiol concentration, suggesting that thiols play a secondary role as antioxidants by mainly quenching 1-hydroxyethyl radicals that are intermediates in the oxidation of ethanol. Increasing the temperature had a minor effect on the rate of oxygen consumption. PMID:26325117

  2. A case study involving allergic reactions to sulfur-containing compounds including, sulfite, taurine, acesulfame potassium and sulfonamides.

    PubMed

    Stohs, Sidney J; Miller, Mark J S

    2014-01-01

    A case study is reported whereby an individual with known sulfite and sulfonamide allergies develops hypersensitivity to taurine above a threshold level as well as to the non-nutritive sweetener acesulfame potassium, compounds that are not normally associated with allergic reactions. Sulfites, sulfonamides, taurine and acesulfame potassium all contain a SO3 moiety. Challenge tests provide evidence for the hypersensitivities to taurine and acesulfame potassium. The subject is also allergic to thiuram mix and thimerosal, sulfur containing compounds, as well as to various food products. This may be the first case where hypersensitivities to taurine and acesulfame potassium have been documented and reported. Several mechanistic explanations are provided for the untoward reactions to taurine and acesulfame potassium.

  3. The first organically templated open-framework metal-sulfites with layered and three-dimensional diamondoid structures.

    PubMed

    Tiwari, Ranjay K; Kumar, Jitendra; Behera, J N

    2016-01-21

    The crystallographic signatures and characterization data of two novel organically templated open-framework zinc-sulfites (NH3CH2CH2NH3)[Zn3(SO3)4], 1, and (CN3H6)2[Zn(SO3)2], 2, are reported for the first time, synthesized under hydrothermal conditions using different amines, namely, ethylenediamine and guanidine, to generate 2D (for 1) and 3D (for 2) assemblies with 4-, 6-, 8- and 12-membered rings.

  4. Effects of Increasing Concentrations of Sodium Sulfite on Deoxynivalenol and Deoxynivalenol Sulfonate Concentrations of Maize Kernels and Maize Meal Preserved at Various Moisture Content

    PubMed Central

    Paulick, Marleen; Rempe, Inga; Kersten, Susanne; Schatzmayr, Dian; Schwartz-Zimmermann, Heidi Elisabeth; Dänicke, Sven

    2015-01-01

    Under moderate climatic conditions, deoxynivalenol (DON) contamination occurs frequently on cereals. Detoxification measures are required to avoid adverse effects on farm animals. In the present study, a wet preservation method with sodium sulfite (Na2SO3) and propionic acid was tested to titrate the optimum Na2SO3-dose for maximum DON reduction of contaminated maize kernels and meal and to examine the interaction between dose and moisture content in dependence on the preservation duration. The DON concentration decreased with increasing amounts of supplemented Na2SO3 and with increasing duration of the preservation period in a bi-exponential fashion. Additionally, the feed structure and moisture content had a significant influence on the decontaminating effect. Variants with 30% moisture content favored higher DON reduction rates compared to 14% moisture, but especially at low moisture contents, DON reduction was more pronounced in maize kernels than in maize meal. In addition to the decrease of DON, a concomitant formation of three different DON sulfonates was observed which differed in their formation pattern over the time course of preservation. The overall results and statistical analysis clarified that Na2SO3 addition of 10 g/kg maize at 30% moisture for eight days was necessary to obtain a complete DON reduction. PMID:25760079

  5. Effects of increasing concentrations of sodium sulfite on deoxynivalenol and deoxynivalenol sulfonate concentrations of maize kernels and maize meal preserved at various moisture content.

    PubMed

    Paulick, Marleen; Rempe, Inga; Kersten, Susanne; Schatzmayr, Dian; Schwartz-Zimmermann, Heidi Elisabeth; Dänicke, Sven

    2015-03-01

    Under moderate climatic conditions, deoxynivalenol (DON) contamination occurs frequently on cereals. Detoxification measures are required to avoid adverse effects on farm animals. In the present study, a wet preservation method with sodium sulfite (Na2SO3) and propionic acid was tested to titrate the optimum Na2SO3-dose for maximum DON reduction of contaminated maize kernels and meal and to examine the interaction between dose and moisture content in dependence on the preservation duration. The DON concentration decreased with increasing amounts of supplemented Na2SO3 and with increasing duration of the preservation period in a bi-exponential fashion. Additionally, the feed structure and moisture content had a significant influence on the decontaminating effect. Variants with 30% moisture content favored higher DON reduction rates compared to 14% moisture, but especially at low moisture contents, DON reduction was more pronounced in maize kernels than in maize meal. In addition to the decrease of DON, a concomitant formation of three different DON sulfonates was observed which differed in their formation pattern over the time course of preservation. The overall results and statistical analysis clarified that Na2SO3 addition of 10 g/kg maize at 30% moisture for eight days was necessary to obtain a complete DON reduction. PMID:25760079

  6. Effects of increasing concentrations of sodium sulfite on deoxynivalenol and deoxynivalenol sulfonate concentrations of maize kernels and maize meal preserved at various moisture content.

    PubMed

    Paulick, Marleen; Rempe, Inga; Kersten, Susanne; Schatzmayr, Dian; Schwartz-Zimmermann, Heidi Elisabeth; Dänicke, Sven

    2015-03-09

    Under moderate climatic conditions, deoxynivalenol (DON) contamination occurs frequently on cereals. Detoxification measures are required to avoid adverse effects on farm animals. In the present study, a wet preservation method with sodium sulfite (Na2SO3) and propionic acid was tested to titrate the optimum Na2SO3-dose for maximum DON reduction of contaminated maize kernels and meal and to examine the interaction between dose and moisture content in dependence on the preservation duration. The DON concentration decreased with increasing amounts of supplemented Na2SO3 and with increasing duration of the preservation period in a bi-exponential fashion. Additionally, the feed structure and moisture content had a significant influence on the decontaminating effect. Variants with 30% moisture content favored higher DON reduction rates compared to 14% moisture, but especially at low moisture contents, DON reduction was more pronounced in maize kernels than in maize meal. In addition to the decrease of DON, a concomitant formation of three different DON sulfonates was observed which differed in their formation pattern over the time course of preservation. The overall results and statistical analysis clarified that Na2SO3 addition of 10 g/kg maize at 30% moisture for eight days was necessary to obtain a complete DON reduction.

  7. Acidification of prehydrolysis liquor and spent liquor of neutral sulfite semichemical pulping process.

    PubMed

    Fatehi, Pedram; Gao, Weijiue; Sun, Yonghui; Dashtban, Mehdi

    2016-10-01

    Acidification has been commercialized for producing kraft lignin from black liquor of kraft pulping process. This work intended to evaluate the effectiveness of acidification in extracting lignocelluloses from the spent liquor of neutral sulfite semichemical pulping (NSSC) process and from prehydrolysis liquor (PHL) of kraft-based dissolving pulp production process. The results showed that the NSSC and PHL spent liquors had some lignin-carbohydrate complexes (LCC), and that the square weighted counts of particles with a chord length of 50-150μm in the spent liquors were significantly increased as pH dropped to 1.5. Interestingly, the acidification reduced the lignosulfonate/lignin content of NSSC and PHL by 13% or 20%, while dropped their oligosugars content by 75% and 38%, respectively. On a dry basis, the precipitates had more carbon, hydrogen and a high heating value of 18-22MJ/kg, but less oxygen, than spent liquors. The precipitates of PHL could be used as fuel. PMID:27394999

  8. Structural and mutational studies of an electron transfer complex of maize sulfite reductase and ferredoxin.

    PubMed

    Kim, Ju Yaen; Nakayama, Masato; Toyota, Hiroshi; Kurisu, Genji; Hase, Toshiharu

    2016-08-01

    The structure of the complex of maize sulfite reductase (SiR) and ferredoxin (Fd) has been determined by X-ray crystallography. Co-crystals of the two proteins prepared under different conditions were subjected to the diffraction analysis and three possible structures of the complex were solved. Although topological relationship of SiR and Fd varied in each of the structures, two characteristics common to all structures were found in the pattern of protein-protein interactions and positional arrangements of redox centres; (i) a few negative residues of Fd contact with a narrow area of SiR with positive electrostatic surface potential and (ii) [2Fe-2S] cluster of Fd and [4Fe-4S] cluster of SiR are in a close proximity with the shortest distance around 12 Å. Mutational analysis of a total of seven basic residues of SiR distributed widely at the interface of the complex showed their importance for supporting an efficient Fd-dependent activity and a strong physical binding to Fd. These combined results suggest that the productive electron transfer complex of SiR and Fd could be formed through multiple processes of the electrostatic intermolecular interaction and this implication is discussed in terms of the multi-functionality of Fd in various redox metabolisms. PMID:26920048

  9. Reaction of Hydrogen Sulfide with Oxygen in the Presence ofSulfite

    SciTech Connect

    Weres, Oleh; Tsao, Leon

    1983-01-01

    Commonly, abatement of hydrogen sulfide emissions from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One Mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. The authors studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDT are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and is too expensive for practical use.

  10. Reaction of hydrogen sulfide with oxygen in the presence of sulfite

    SciTech Connect

    Weres, O.; Tsao, L.

    1983-01-14

    Commonly, abatement of hydrogen sulfide emission from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. We studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDTA are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and is too expensive for practical use. 33 figures, 9 tables.

  11. Asymmetric synthesis of allylic sulfonic acids: enantio- and regioselective iridium-catalyzed allylations of Na2SO3.

    PubMed

    Liu, Wei; Zhao, Xiao-ming; Zhang, Hong-bo; Zhang, Liang; Zhao, Ming-zhu

    2014-12-15

    An enantioselective allylation reaction of allylic carbonates with sodium sulfite (Na2 SO3 ) catalyzed by Ir complex was accomplished, providing allylic sulfonic acids in good to excellent yields with a high level of enantio- and regioselectivities. (R)-2-Phenyl-2-sulfoacetic acid, a key intermediate for the synthesis of Cefsulodin and Sulbenicillin, was synthesized as well.

  12. Asymmetric synthesis of allylic sulfonic acids: enantio- and regioselective iridium-catalyzed allylations of Na2SO3.

    PubMed

    Liu, Wei; Zhao, Xiao-ming; Zhang, Hong-bo; Zhang, Liang; Zhao, Ming-zhu

    2014-12-15

    An enantioselective allylation reaction of allylic carbonates with sodium sulfite (Na2 SO3 ) catalyzed by Ir complex was accomplished, providing allylic sulfonic acids in good to excellent yields with a high level of enantio- and regioselectivities. (R)-2-Phenyl-2-sulfoacetic acid, a key intermediate for the synthesis of Cefsulodin and Sulbenicillin, was synthesized as well. PMID:25367779

  13. Effects of sulfite on the uptake and binding of benzo[a]pyrene diol epoxide in cultured murine respiratory epithelial cells.

    PubMed Central

    Green, J L; Jones, B C; Reed, G A

    1994-01-01

    Sulfur dioxide (SO2) may act as a cocarcinogen with benzo[a]pyrene (BaP) in the respiratory tract. We have modeled this effect by examining the interactions of 7r,8t-dihydroxy-9t,10t-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE) with sulfite, the physiological form of SO2, in a murine respiratory epithelial cell line (C10). We exposed C10 cells to [3H]-anti-BPDE and determined the effects of 1 and 10 mM sulfite on the uptake and subcellular localization of labeled products. Autoradiographic analysis showed that sulfite doubled the nuclear localization of anti-BPDE-derived materials after a 4-hr incubation period. The net nuclear localization of anti-BPDE-derived materials was not affected by sulfite during the first 60 min, but nuclear localization continued to increase in the sulfite-containing incubations throughout the 4-hr incubation period. Little increase in nuclear localization of anti-BPDE-derived material was noted in the incubations without sulfite after 60 min. Subcellular fractionation was performed to determine the amount of label associated with cytosolic and nuclear fractions and to determine covalent binding to protein and DNA. Sulfite produced a modest increase in the amount of [3H]-anti-BPDE-derived products bound to protein; however, binding to nuclear DNA increased by more than 200% with 10 mM sulfite. Analysis of the supernatants from the cytosolic and nuclear fractions of cells exposed to anti-BPDE and sulfite demonstrated the presence of 7r,8t,9t-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene-10c-su lfonate (BPT-10-sulfonate). [3H]-BPT-10-sulfonate was unable to enter C10 cells, suggesting that it is formed intracellularly.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 1. Figure 2. Figure 3. Figure 3. Figure 3. Figure 3. Figure 3. Figure 3. Figure 4. PMID:8033853

  14. Role of. pi. -cation radicals in the enzymatic cycles of peroxidases, catalases, and nitrite and sulfite reductases

    SciTech Connect

    Hanson, L K; Chang, C K; Davis, M S; Fajer, J

    1980-01-01

    Charge iterative extended Hueckel calculations, and magnetic and optical results on porphyrins, chlorins, and isobacteriochlorins (1) suggest that the catalytic cycles of the enzymes horseradish peroxidase, catalase, Neurospora crassa catalase, and nitrite and sulfite reductases proceed via ..pi..-cation radicals of their prosthetic groups; (2) offer distinguishing features for the optical and magnetic spectra of these radicals, pertinent to their detection as enzymatic intermediates; (3) reconcile the seemingly contradictory optical and NMR data on Compounds I of horseradish peroxidase; and (4) predict that the axial ligation of the heme differs for horseradish peroxidase and catalase.

  15. Radiolysis of aqueous solutions of 2-aminoethanethiosulfuric acid. [Gamma radiation

    SciTech Connect

    Grachev, S.A.; Koroleva, I.K.; Kropachev, E.V.; Litvyakova, G.I.

    1982-07-10

    In the radiolysis products of aerated and deaerated solutions of the 2-aminoethanethiosulfuric acid the authors have identified cystamine monoxide, cystamine, taurine, mercamine, the sulfate ion, the sulfite ion, and the dithionate ion. The yields of these products under different conditions have been determined. Results indicated that the sulfate ion is formed both from the divalent and the hexavalent sulfur atom of the 2-aminoethanethiosulfuric acid moelcule. A possible radiolysis mechanism is discussed.

  16. Direct demonstration of the presence of coordinated sulfate in the reaction pathway of Arabidopsis thaliana sulfite oxidase using 33S labeling and ESEEM spectroscopy

    PubMed Central

    Astashkin, Andrei V.; Johnson-Winters, Kayunta; Klein, Eric L.; Byrne, Robert S.; Hille, Russ; Raitsimring, Arnold M.; Enemark, John H.

    2008-01-01

    Sulfite oxidase from Arabidopsis thaliana has been reduced at pH = 6 with sulfite labeled with 33S (nuclear spin I = 3/2), followed by reoxidation by ferricyanide to generate the Mo(V) state of the active center. To obtain information about the hyperfine interaction (hfi) of 33S with Mo(V), continuous wave EPR and electron spin echo envelope modulation (ESEEM) experiments have been performed. The interpretation of the EPR and ESEEM spectra was facilitated by a theoretical analysis of the nuclear transition frequencies expected for the situation of the nuclear quadrupole interaction being much stronger than the Zeeman and hyperfine interactions. The isotropic hfi constant of 33S determined in these experiments was about 3 MHz, which demonstrates the presence of coordinated sulfate in the sulfite-reduced low-pH form of the plant enzyme. PMID:17983221

  17. The Crystal Structure of Desulfovibrio vulgaris Dissimilatory Sulfite Reductase Bound to DsrC Provides Novel Insights into the Mechanism of Sulfate Respiration*S⃞

    PubMed Central

    Oliveira, Tânia F.; Vonrhein, Clemens; Matias, Pedro M.; Venceslau, Sofia S.; Pereira, Inês A. C.; Archer, Margarida

    2008-01-01

    Sulfate reduction is one of the earliest types of energy metabolism used by ancestral organisms to sustain life. Despite extensive studies, many questions remain about the way respiratory sulfate reduction is associated with energy conservation. A crucial enzyme in this process is the dissimilatory sulfite reductase (dSiR), which contains a unique siroheme-[4Fe4S] coupled cofactor. Here, we report the structure of desulfoviridin from Desulfovibrio vulgaris, in which the dSiR DsrAB (sulfite reductase) subunits are bound to the DsrC protein. The α2β2γ2 assembly contains two siroheme-[4Fe4S] cofactors bound by DsrB, two sirohydrochlorins and two [4Fe4S] centers bound by DsrA, and another four [4Fe4S] centers in the ferredoxin domains. A sulfite molecule, coordinating the siroheme, is found at the active site. The DsrC protein is bound in a cleft between DsrA and DsrB with its conserved C-terminal cysteine reaching the distal side of the siroheme. We propose a novel mechanism for the process of sulfite reduction involving DsrAB, DsrC, and the DsrMKJOP membrane complex (a membrane complex with putative disulfide/thiol reductase activity), in which two of the six electrons for reduction of sulfite derive from the membrane quinone pool. These results show that DsrC is involved in sulfite reduction, which changes the mechanism of sulfate respiration. This has important implications for models used to date ancient sulfur metabolism based on sulfur isotope fractionations. PMID:18829451

  18. Multiple sulfur isotope signatures of sulfite and thiosulfate reduction by the model dissimilatory sulfate-reducer, Desulfovibrio alaskensis str. G20

    PubMed Central

    Leavitt, William D.; Cummins, Renata; Schmidt, Marian L.; Sim, Min S.; Ono, Shuhei; Bradley, Alexander S.; Johnston, David T.

    2014-01-01

    Dissimilatory sulfate reduction serves as a key metabolic carbon remineralization process in anoxic marine environments. Sulfate reducing microorganisms can impart a wide range in mass-dependent sulfur isotopic fractionation. As such, the presence and relative activity of these organisms is identifiable from geological materials. By extension, sulfur isotope records are used to infer the redox balance of marine sedimentary environments, and the oxidation state of Earth's oceans and atmosphere. However, recent work suggests that our understanding of microbial sulfate reduction (MSRs) may be missing complexity associated with the presence and role of key chemical intermediates in the reductive process. This study provides a test of proposed metabolic models of sulfate reduction by growing an axenic culture of the well-studied MSRs, Desulfovibrio alaskensis strain G20, under electron donor limited conditions on the terminal electron acceptors sulfate, sulfite or thiosulfate, and tracking the multiple S isotopic consequences of each condition set. The dissimilatory reduction of thiosulfate and sulfite produce unique minor isotope effects, as compared to the reduction of sulfate. Further, these experiments reveal a complex biochemistry associated with sulfite reduction. That is, under high sulfite concentrations, sulfur is shuttled to an intermediate pool of thiosulfate. Site-specific isotope fractionation (within thiosulfate) is very large (34ε ~ 30‰) while terminal product sulfide carries only a small fractionation from the initial sulfite (34ε < 10‰): a signature similar in magnitude to sulfate and thiosulfate reduction. Together these findings show that microbial sulfate reduction (MSR) is highly sensitive to the concentration of environmentally important sulfur-cycle intermediates (sulfite and thiosulfate), especially when thiosulfate and the large site-specific isotope effects are involved. PMID:25505449

  19. Enantioselective transformation of Na2SO3 into allylic sulfonic acids under Pd catalysis.

    PubMed

    Liu, Wei; Zhao, Xiao-ming; Zhang, Hong-bo; Zhang, Liang

    2015-01-14

    Pd-catalyzed asymmetric allylic sulfonation of di-aryl-substituted allylic acetates with sodium sulfite (Na2SO3) in THF-H2O at room temperature was described. This method directly provided allylic sulfonic acids in up to excellent yield and enantioselectivity. PMID:25415622

  20. Dissociation and reduction of covalent β-lactoglobulin-quinone adducts by dithiothreitol, tris(2-carboxyethyl)phosphine, or sodium sulfite.

    PubMed

    Jongberg, Sisse; Lund, Marianne N; Otte, Jeanette

    2015-06-01

    Covalent protein-phenol adducts, generated by reaction of protein nucleophiles with quinones, have recently attracted increased attention because the interactions change the functionality and physicochemical properties of proteins in biological and food systems. The formation of such covalent adducts between β-lactoglobulin (β-LG) and the quinone of 4-methylcatechol, 4-methylbenzoquinone (4MBQ), and subsequent reduction by dithiothreitol (DTT), tris(2-carboxyethyl)phosphine (TCEP), or sodium sulfite was investigated by mass spectrometry. The results showed that 19.0 ± 8.8% of β-LG reacted with 4MBQ when present in equimolar ratio at 20°C (pH 8.0) to yield the protein-phenol adduct (β-LG-Q). Following treatment with sulfite, DTT, or TCEP, 75, 68, or 36%, respectively, of the formed β-LG-Q adduct dissociated. Different reaction mechanisms were proposed for the reduction of β-LG and β-LG-Q by each of the reducing agents. These results show that on reductive sample preparation for analysis of protein samples, not only are protein polymers formed through oxidative disulfide bonds reduced into the individual protein constituents but also a large part of any protein-phenol adducts present will dissociate and, thus, give a false picture of the level of protein-protein interactions that have occurred in the sample. PMID:25700864

  1. Potential bronchoconstrictor stimuli in acid fog.

    PubMed

    Balmes, J R; Fine, J M; Gordon, T; Sheppard, D

    1989-02-01

    Acid fog is complex and contains multiple stimuli that may be capable of inducing bronchoconstriction. These stimuli include sulfuric and niric acids, the principal inorganic acids present; sulfites, formed in the atmosphere as a reaction product of sulfur dioxide and water droplets; fog water itself, a hypoosmolar aerosol; the organic acid hydroxymethanesulfonate, the bisulfite adduct of formaldehyde; and gaseous pollutants, e.g., sulfur dioxide, oxides of nitrogen, ozone. Given this complexity, evaluation of the respiratory health effects of naturally occurring acid fog requires assessment of the bronchoconstrictor potency of each component stimulus and possible interactions among these stimuli. We summarize the results of three studies that involve characterization of the bronchoconstrictor potency of acid fog stimuli and/or their interaction in subjects with asthma. The results of the first study indicate that titratable acidity appears to be a more important stimulus to bronchoconstriction than is pH. The results of the second study demonstrate that sulfite species are capable of inducing bronchoconstriction, especially when inhaled at acid pH. The results of the third study suggest that acidity can potentiate hypoosmolar fog-induced bronchoconstriction.

  2. Potential bronchoconstrictor stimuli in acid fog

    SciTech Connect

    Balmes, J.R.; Fine, J.M.; Gordon, T.; Sheppard, D.

    1989-02-01

    Acid fog is complex and contains multiple stimuli that may be capable of inducing bronchoconstriction. These stimuli include sulfuric and nitric acids, the principal inorganic acids present; sulfites, formed in the atmosphere as a reaction product of sulfur dioxide and water droplets; fog water itself, a hypoosmolar aerosol; the organic acid hydroxymethanesulfonate, the bisulfite adduct of formaldehyde; and gaseous pollutants, e.g., sulfur dioxide, oxides of nitrogen, ozone. Given this complexity, evaluation of the respiratory health effects of naturally occurring acid fog requires assessment of the bronchoconstrictor potency of each component stimulus and possible interactions among these stimuli. We summarize the results of three studies that involve characterization of the bronchoconstrictor potency of acid fog stimuli and/or their interaction in subjects with asthma. The results of the first study indicate that titratable acidity appears to be a more important stimulus to bronchoconstriction than is pH. The results of the second study demonstrate that sulfite species are capable of inducing bronchoconstriction, especially when inhaled at acid pH. The results of the third study suggest that acidity can potentiate hypoosmolar fog-induced bronchoconstriction.

  3. Effect of sodium and potassium salts on the extraction of 1-butanol from aqueous solution by the ethyl esters of soybean oil fatty acids

    SciTech Connect

    Compere, A.L.; Googin, J.M.; Griffith, W.L.

    1985-01-01

    The effect of 0 to 0.15 M sodium chloride, sulfate, and sulfite, and potassium acid phosphate on the extraction of 0.1 to 4.1% 1-butanol from aqueous solutions (derived from fermentation of wood pulp liquors) at 25, 40, and 55 C was evaluated using a factorial experiment. The changes in distribution coefficient were small, with mild increases occurring with increasing temperature and increasing sodium chloride, sodium sulfate, and potassium acid phosphate. Mild decreases in 1-butanol extraction occurred with increasing sodium sulfite. 6 refs., 4 tabs.

  4. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced & Cooled) A Appendix A to Subpart HHHH of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  5. 21 CFR Appendix A to Part 101 - Monier-Williams Procedure (With Modifications) for Sulfites in Food, Center for Food Safety and...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Monier-Williams Procedure (With Modifications) for...-Williams Procedure (With Modifications) for Sulfites in Food, Center for Food Safety and Applied Nutrition...-Williams apparatus. Component identification is given in text. ER01JA93.363 Figure 2. Diagram of bubbler...

  6. Asymmetric synthesis of tetrahydroquinolin-3-ols via CoCl2-catalyzed reductive cyclization of nitro cyclic sulfites with NaBH4.

    PubMed

    Jagdale, Arun R; Reddy, R Santhosh; Sudalai, Arumugam

    2009-02-19

    A new method for the construction of chiral 3-substituted tetrahydroquinoline derivatives based on asymmetric dihydroxylation and CoCl(2)-catalyzed reductive cyclization of nitro cyclic sulfites with NaBH(4) has been described with high optical purities. This method has been successfully applied in the formal synthesis of PNU 95666E and anachelin H chromophore.

  7. Protective performances of two anti-graffiti treatments towards sulfite and sulfate formation in SO 2 polluted model environment

    NASA Astrophysics Data System (ADS)

    Carmona-Quiroga, Paula María; Panas, Itai; Svensson, Jan-Erik; Johansson, Lars-Gunnar; Blanco-Varela, María Teresa; Martínez-Ramírez, Sagrario

    2010-11-01

    Specific strategies for protection are being developed to counter both the staining and corrosive effects of polluted air in cities, as well as to allow for efficient removal of unwanted graffiti paintings. These protection strategies employ molecules with tailored functionalities, e.g. being hydrophobic, while maintaining porosity for molecular water vapour permeation. The present study employs SO 2 and water to probe the behaviors of two anti-graffiti treatments, a water-base fluoroalkylsiloxane ("Protectosil Antigraffiti" marketed by Degussa) and an organically modified silicate (Ormosil) synthesized from a polymer chain (polydimethyl siloxane, PDMS) and two network forming alkoxides (Zr propoxide and methyl triethoxy silane, MTES) dissolved in n-propanol, on five building materials, comprising limestone, aged lime mortar, hydrated cement mortar, granite, and brick material. The materials were exposed to a synthetic atmosphere for 20 h in a climate chamber, 0.78 ± 0.03 ppm of SO 2 and 95% RH. Diffuse reflectance Fourier transform infrared (DR-FTIR) spectra were registered before and after exposure in the climate chamber in the cases of both treated and untreated samples. DR-FTIR, scanning electron microscope (SEM) images and energy dispersive X-ray (EDX) analyses, suggest the anti-graffiti Ormosil to suppress formation of calcium sulfite hemihydrate (the primary initial product of the reaction of calcium compounds with SO 2 and water) on carbonate materials (limestone and lime mortar). In case of the granite, brick and cement mortar, Ormosil has a negligible influence on the SO 2 capture. While no sulfite formation was detected by DR-FTIR, gypsum is inferred to form due to metal oxides and minority compounds catalysed oxidation of sulfite to sulfate. In case of brick, this understanding finds support from SEM images as well as EDX. A priori presence of gypsum in hydrated cement mortars prevents positive identification by SEM. However, support for sulfur

  8. Selection and validation of reference genes for quantitative real-time PCR studies during Saccharomyces cerevisiae alcoholic fermentation in the presence of sulfite.

    PubMed

    Nadai, Chiara; Campanaro, Stefano; Giacomini, Alessio; Corich, Viviana

    2015-12-23

    Sulfur dioxide is extensively used during industrial fermentations and contributes to determine the harsh conditions of winemaking together with low pH, high sugar content and increasing ethanol concentration. Therefore the presence of sulfite has to be considered in yeast gene expression studies to properly understand yeast behavior in technological environments such as winemaking. A reliable expression pattern can be obtained only using an appropriate reference gene set that is constitutively expressed regardless of perturbations linked to the experimental conditions. In this work we tested 15 candidate reference genes suitable for analysis of gene expression during must fermentation in the presence of sulfite. New reference genes were selected from a genome-wide expression experiment, obtained by RNA sequencing of four Saccharomyces cerevisiae wine strains grown in enological conditions. Their performance was compared to that of the most common genes used in previous studies. The most popular software based on different statistical approaches (geNorm, NormFinder and BestKeeper) were chosen to evaluate expression stability of the candidate reference genes. Validation was obtained using other wine strains by comparing normalized gene expression data with transcriptome quantification both in the presence and absence of sulfite. Among 15 reference genes tested ALG9, FBA1, UBC6 and PFK1 appeared to be the most reliable while ENO1, PMA1, DED1 and FAS2 were the worst. The most popular reference gene ACT1, widely used for S. cerevisiae gene expression studies, showed a stability level markedly lower than those of our selected reference genes. Finally, as the expression of the new reference gene set remained constant over the entire fermentation process, irrespective of the perturbation due to sulfite addition, our results can be considered also when no sulfite is added to the must.

  9. Effect of inhaled sulfur dioxide and systematic sulfite on the induction of lung carcinoma in rats by benzo(a)pyrene

    SciTech Connect

    Gunnison, A.F.; Sellakumar, A.; Snyder, E.A.; Currie, D.

    1988-06-01

    Rats were treated with BaP by 15 consecutive weekly intratracheal instillations. Some of these rats were simultaneously exposed either to SO/sub 2/ by inhalation or to sulfite/bisulfite anions that accumulated systematically from endogenous generation in rats with induced sulfite oxidase deficiency. The total treatment period spanned 21 weeks, after which the rats were observed for the development of tumors. BaP-treated rats began to die with SQCA of the respiratory tract at approximately 200 days after the first BaP treatment and at 2 years after the first treatment nearly all rats in the BaP-treated groups had died, most with SQCA. Survival in the control groups was excellent and the health of all groups (aside from pulmonary SQCA in BaP-treated groups) was also excellent. The probability of dying with a pulmonary SQCA in the experimental groups treated with BaP, BaP plus inhaled SO/sub 2/, and BaP plus systemic sulfite/bisulfite was calculated by the log rank analysis. The data sets of SQCA probability from these groups were not statistically different by the chi/sup 2/ test indicating that, in this experiment, neither inhalation exposure to SO/sub 2/ nor systemic exposure to sulfite/bisulfite anions affected the induction of SQCA of the lung by intratracheally instilled BaP. The authors conclude that the results of this study do not support an etiological role for either SO/sub 2/ or sulfite/bisulfite anions in the induction of SQCA of the respiratory tract by BaP.

  10. Sulfur amino acid auxotrophy in Micrococcus species isolated from human skin.

    PubMed

    Farrior, J W; Kloos, W E

    1976-12-01

    Since methionine and (or) cysteine are required by a large percentage of natural auxotrophic Micrococcus strains isolated from human skin, investigations were directed to determine the specific enzymes affected in sulfur amino acid biosynthesis. Known intermediates in the interrelated cysteine and methionine biosynthetic pathways were tested as growth stimulants. Based on these growth studies, sulfur amino acid auxotrophs were grouped into three cysteine classes and five methionine classes. Selected auxotrophs of M. luteus had deficiencies in ATP sulfurylase (EC 2.7.7.4) and adenosine-5-sulfatophosphate (APS) kinase (EC 2.7.1.25), sulfite reductase (EC 1.8.1.2), serine transacetylase (EC 2.3.1.30), or beta-cystathionase (EC 4.4.1.8) activity; auxotrophs of M. lylae had deficiencies in sulfite reductase and serine transacetylase, beta-cystathionase, or N5, N10-methyltetrahydrofolate reductase (EC 1.1.1.68) activity; all auxotrophs of M. sedentarius tested had deficiencies in N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M. nishinomiyaensis had deficiencies in adenosine-3-phosphate-5-sulfatophosphate (PAPS) reductase, sulfite reductase, serine transacetylase, or N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M. varians had deficiencies in APS kinase, PAPS reductase, sulfite reductase, homoserine omicron-transsuccinylase, beta-cystathionase, or N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M. kristinae had deficiencies in serine transacetylase or cystathionine-gamma-synthase (EC 4.2.99.9) activity; auxotrophs of M. roseus had deficiencies in PAPS reductase, sulfite reductase, or serine transacetylase activity. Results of studies with various mutagens suggested that sulfur amino acid auxotrophy was primarily the result of a single base substitution in usually one or two of the genes controlling biosynthesis. A preliminary study of the amino acid composition of sweat suggested that this important source of nutrients

  11. Identification of the Bovine Arachnomelia Mutation by Massively Parallel Sequencing Implicates Sulfite Oxidase (SUOX) in Bone Development

    PubMed Central

    Drögemüller, Cord; Tetens, Jens; Sigurdsson, Snaevar; Gentile, Arcangelo; Testoni, Stefania; Lindblad-Toh, Kerstin; Leeb, Tosso

    2010-01-01

    Arachnomelia is a monogenic recessive defect of skeletal development in cattle. The causative mutation was previously mapped to a ∼7 Mb interval on chromosome 5. Here we show that array-based sequence capture and massively parallel sequencing technology, combined with the typical family structure in livestock populations, facilitates the identification of the causative mutation. We re-sequenced the entire critical interval in a healthy partially inbred cow carrying one copy of the critical chromosome segment in its ancestral state and one copy of the same segment with the arachnomelia mutation, and we detected a single heterozygous position. The genetic makeup of several partially inbred cattle provides extremely strong support for the causality of this mutation. The mutation represents a single base insertion leading to a premature stop codon in the coding sequence of the SUOX gene and is perfectly associated with the arachnomelia phenotype. Our findings suggest an important role for sulfite oxidase in bone development. PMID:20865119

  12. Inhibition of superoxide dismutase, Vitamin C and glutathione on chemiluminescence produced by luminol and the mixture of sulfite and bisulfite

    NASA Astrophysics Data System (ADS)

    Geng, Hong; Meng, Ziqiang

    2006-05-01

    In a system which consisted of luminol (3-aminophthalhydrazide), cobalt sulfate (CoSO 4), alkaline buffer and the mixture of NaSO 3 and sodium bisulfite (NaHSO 3) (sulfite and bisulfite = 3:1, m/m), a strong chemiluminescence (CL) was observed using a BPCL ultra-weak luminometer. The CL signals resulted from 3-aminophthalate (the product of oxidized luminol), and were affected by the buffer pH, buffer medium and the concentrations of luminol, CoSO 4 and the NaSO 3-NaHSO 3 mixture. The observation that the CL intensities were inhibited by superoxide dismutase (SOD), Vitamin C (Vc) and glutathione (GSH) in a dose-dependent manner suggested that superoxide radical (O 2rad -) was involved in the CL reaction and responsible for oxidation of luminol.

  13. Desulfitibacter alkalitolerans gen. nov., sp. nov., an anaerobic, alkalitolerant, sulfite-reducing bacterium isolated from a district heating plant.

    PubMed

    Nielsen, Marie Bank; Kjeldsen, Kasper Urup; Ingvorsen, Kjeld

    2006-12-01

    A novel alkalitolerant, anaerobic bacterium, designated strain sk.kt5(T), was isolated from a metal coupon retrieved from a corrosion-monitoring reactor of a Danish district heating plant (Skanderborg, Jutland). The cells of strain sk.kt5(T) were motile, rod-shaped (0.4-0.6 x 2.5-9.6 microm), stained Gram-positive and formed endospores. Strain sk.kt5(T) grew at pH 7.6-10.5 (with optimum growth at pH 8.0-9.5), at temperatures in the range 23-44 degrees C (with optimum growth at 35-37 degrees C), at NaCl concentrations in the range 0-5 % (w/v) (with optimum growth at 0-0.5 %) and required yeast extract for growth. Only a limited number of substrates were utilized as electron donors, including betaine, formate, lactate, methanol, choline and pyruvate. Elemental sulfur, sulfite, thiosulfate, nitrate and nitrite, but not sulfate or Fe(III) citrate, were used as electron acceptors. The G+C content of the DNA was 41.6 mol%. Phylogenetic analyses of the sequence data for the dsrAB genes [encoding the major subunits of dissimilatory (bi)sulfite reductase] and the 16S rRNA gene placed strain sk.kt5(T) within a novel lineage in the class Clostridia of the phylum Firmicutes. Taken together, the physiological and genotypic data suggest that strain sk.kt5(T) represents a novel species within a novel genus, for which the name Desulfitibacter alkalitolerans gen. nov., sp. nov. is proposed. The type strain of Desulfitibacter alkalitolerans is sk.kt5(T) (=JCM 12761(T)=DSM 16504(T)).

  14. Growth and toxin production by Clostridium botulinum on sliced raw potatoes in a modified atmosphere with and without sulfite.

    PubMed

    Solomon, H M; Rhodehamel, E J; Kautter, D A

    1998-01-01

    The ability of Clostridium botulinum type A or B spores to grow and produce toxin on fresh raw potatoes in a modified atmosphere with or without sulfite was investigated at 22 degrees C. Fresh, peeled, sliced potatoes, untreated or dipped for 2 min into 0.7% sulfite solution and drained, were surface-inoculated at several concentration levels with a mixture of C. botulinum spores, either type A or B. They were placed in a modified atmosphere (30% N/70% CO2) within oxygen-impermeable bags (200 g/bag) and incubated at room temperature (22 degrees C). Toxicity was tested on days 0, 3, 4, 5, 6, and 7. After incubation, the potatoes were blended and centrifuged, and the Millipore-filtered supernatant fluid was injected intraperitoneally into mice. Sensory evaluation, except taste, was also performed. Potatoes inoculated with C. botulinum type A spores but untreated with NaHSO3 became toxic in 4 to 5 days, which coincided with the sensory evaluation "unfit for human consumption". Potatoes treated with NaHSO3 regardless of inoculum size or residual SO2 levels appeared acceptable for human consumption through day 7, even though they were toxic after 4 days of incubation. Although toxicity from type B spores occurred later and in fewer test samples than toxicity from type A, some potatoes again appeared acceptable but were toxic. Thus, although NaHSO3 markedly extended the consumer acceptability of peeled, sliced, raw potatoes at the abuse temperature, it did not inhibit outgrowth and toxin production by C. botulinum under these conditions.

  15. Effect of antibrowning agents on browning and intermediate formation in the glucose-glutamic acid model.

    PubMed

    Lim, Seong-Il; Kwak, Eun-Jung; Lee, Ok-Hwan; Lee, Boo-Yong

    2010-10-01

    In this study, the inhibitory effects of antibrowning agents on browning and the formation of intermediates such as 3-deoxyglucosone (3-DG) and hydroxymethylfurfural (HMF) were evaluated with a glucose-glutamic acid model for soybean paste. The initial antibrowning capacity was measured in the following order: pentasodium tripolyphosphate < citric acid and oxalic acid < cysteine and glutathione < sodium sulfite. Our data showed that antibrowning agents, such as pentasodium tripolyphosphate, citric acid, and oxalic acid, were maintained antibrowning capacities during storage at both 4 and 30 °C, respectively. However, both cysteine and glutathione was reduced with storage time, especially in the air. A marked effect of nitrogen treatment was noted for 3 of the antibrowning agents after storage in air at 30 °C in the following order: sodium sulfite < cysteine < glutathione. The formation ratio of 3-DG and HMF was higher after storage at 30 °C than at 4 °C. These compounds were produced most abundantly in the presence of sodium sulfite, and the yields were not related significantly to the degree of browning. Citric acid and oxalic acid were identified as the most effective in inhibitors of browning and intermediates, even during storage in air at 30 °C.

  16. 40 CFR 63.444 - Standards for the pulping system at sulfite processes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... strong liquor storage tank; and (iii) Each acid condensate storage tank. (b) Equipment listed in... systems listed in paragraph (a) of this section and the vents, wastewater, and condensate streams from...

  17. 40 CFR 63.444 - Standards for the pulping system at sulfite processes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... strong liquor storage tank; and (iii) Each acid condensate storage tank. (b) Equipment listed in... systems listed in paragraph (a) of this section and the vents, wastewater, and condensate streams from...

  18. 40 CFR 63.444 - Standards for the pulping system at sulfite processes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... strong liquor storage tank; and (iii) Each acid condensate storage tank. (b) Equipment listed in... systems listed in paragraph (a) of this section and the vents, wastewater, and condensate streams from...

  19. The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.

    ERIC Educational Resources Information Center

    Robles, E. G.

    The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

  20. Diversity of sulfate-reducing bacteria in oxic and anoxic regions of a microbial mat characterized by comparative analysis of dissimilatory sulfite reductase genes

    SciTech Connect

    Minz, D.; Flax, J.L.; Green, S.J.; Muyzer, G.; Cohen, Y.; Wagner, M.; Rittmann, B.E.; Stahl, D.A.

    1999-10-01

    Sequence analysis of genes encoding dissimilatory sulfite reductase (DSR) was used to identify sulfate-reducing bacteria in a hypersaline microbial mat and to evaluate their distribution in relation to levels of oxygen. The most highly diverse DSR sequences, most related to those of the Desulfonema-like organisms within the {delta}-proteobacteria, were recovered from oxic regions of the mat. This observation extends those of previous studies by the authors and others associating Desulfonema-like organisms with oxic habitats.

  1. Photoproduction of glyoxylic acid in model wine: Impact of sulfur dioxide, caffeic acid, pH and temperature.

    PubMed

    Grant-Preece, Paris; Schmidtke, Leigh M; Barril, Celia; Clark, Andrew C

    2017-01-15

    Glyoxylic acid is a tartaric acid degradation product formed in model wine solutions containing iron and its production is greatly increased by exposure to UV-visible light. In this study, the combined effect of sulfur dioxide, caffeic acid, pH and temperature on the light-induced (⩾300nm) production of glyoxylic acid in model wine containing tartaric acid and iron was investigated using a Box-Behnken experimental design and response surface methodology (RSM). Glyoxylic acid produced in the irradiated model wine was present in free and hydrogen sulfite adduct forms and the measured total, free and percentage free glyoxylic acid values were modeled using RSM. Sulfur dioxide significantly decreased the total amount of glyoxylic acid produced, but could not prevent its production, while caffeic acid showed no significant impact. The interaction between pH and temperature was significant, with low pH values and low temperatures giving rise to higher levels of total glyoxylic acid.

  2. Sulfite and base for the treatment of familial amyloidotic polyneuropathy: two additive approaches to stabilize the conformation of human amyloidogenic transthyretin.

    PubMed

    Altland, Klaus; Winter, Pia; Saraiva, Maria Joao M; Suhr, Ole

    2004-02-01

    Recently, we presented evidence that sulfite protects transthyretin (TTR) from normal human individuals and heterozygotes with amyloidogenic TTR mutations against the decay of tetramers into monomers. In this paper we demonstrate a stabilizing effect of sulfite on TTR tetramers from a familial amyloidotic polyneuropathy (FAP) patient homozygous for the most-common amyloidogenic TTR-V30 M mutation. We compare the conformational stability of partially sulfonated TTR from a heterozygote for normal TTR and amyloidogenic TTR-V30 M with the stability of untreated TTR from a compound heterozygote for amyloidogenic TTR-V30 M and TTR-T119 M known to have only minor or no problems of FAP. Using a combination of polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate (SDS) gradient PAGE we demonstrate that TTR dimers containing amyloidogenic TTR mutations decay into monomers at pH<7.4. Increasing the pH by some 0.2 units within physiological ranges, i.e., pH 7.0-7.4, and sulfonation of TTR were observed to have additive inhibitory effects on the transition of dimers into monomers. We conclude that mild acidifying episodes in the interstitial volume of tissues at risk for amyloidosis could contribute to the development of FAP. Early and permanent efforts to counteract acidosis by treatment with base could possibly help to delay the onset of the disease. The intake of sulfite could support these efforts.

  3. Degradation of vinyl chloride (VC) by the sulfite/UV advanced reduction process (ARP): effects of process variables and a kinetic model.

    PubMed

    Liu, Xu; Yoon, Sunhee; Batchelor, Bill; Abdel-Wahab, Ahmed

    2013-06-01

    Vinyl chloride (VC) poses a threat to humans and environment due to its toxicity and carcinogenicity. In this study, an advanced reduction process (ARP) that combines sulfite with UV light was developed to destroy VC. The degradation of VC followed pseudo-first-order decay kinetics and the effects of several experimental factors on the degradation rate constant were investigated. The largest rate constant was observed at pH9, but complete dechlorination was obtained at pH11. Higher sulfite dose and light intensity were found to increase the rate constant linearly. The rate constant had a little drop when the initial VC concentration was below 1.5mg/L and then was approximately constant between 1.5mg/L and 3.1mg/L. A degradation mechanism was proposed to describe reactions between VC and the reactive species that were produced by the photolysis of sulfite. A kinetic model that described major reactions in the system was developed and was able to explain the dependence of the rate constant on the experimental factors examined. This study may provide a new treatment technology for the removal of a variety of halogenated contaminants.

  4. Cyclic voltammetric determination of free and total sulfite in muscle foods using an acetylferrocene-carbon black-poly(vinyl butyral) modified glassy carbon electrode.

    PubMed

    Wang, Li; Xu, Lei

    2014-10-22

    A novel method for the selective extraction of free (pH 8.4) and total sulfite (pH 11.0) from muscle foods and the following determination by a voltammetric sensor was reported. The proposed method was based on the eletrocatalytic oxidation of sulfite at modified glassy carbon electrode (GCE) fabricated by immobilizing 9 μg of acetylferrocene on the surface of GCE along with 35 μg of carbon black to improve the electron transfer within poly(vinyl butyral) membrane matrix. The external standard calibration curve was linear in the range of 0.03-4.0 mmol L(-1) with a detection limit of 15 μmol L(-1). This method had been applied to the determination of free and total sulfite in shrimp muscle fortified samples and compared with an ion chromatography method. The proposed electrode and analysis methods were proven to be sensitive, accurate, and rapid and exhibited very good reproducibility and stability under the used conditions.

  5. The identity of the exchangeable sulfur-containing ligand at the Mo(V) center of R160Q human sulfite oxidase

    PubMed Central

    Klein, Eric L.; Raitsimring, Arnold M.; Astashkin, Andrei V.; Rajapakshe, Asha; Johnson-Winters, Kayunta; Arnold, Anna R.; Potapov, Alexei

    2012-01-01

    In our previous study of the fatal R160Q mutant of human sulfite oxidase (hSO) at low pH (Astashkin et al. J. Am. Chem. Soc. 2008, 130, 8471–8480) a new Mo(V) species, denoted “Species 1”, was observed at low pH values. Species 1 was ascribed to a six-coordinate Mo(V) center with an exchangeable terminal oxo ligand and an equatorial sulfate group on the basis of pulsed EPR spectroscopy and 33S and 17O labeling. Here we report new results for Species 1 of R160Q, based on substitution of the sulfur-containing ligand by a phosphate group, pulsed EPR spectroscopy in Ka- and W-bands, and extensive density functional theory (DFT) calculations applied to large, more realistic molecular models of the enzyme active site. The combined results unambiguously show that Species 1 has an equatorial sulfite as the only exchangeable ligand. The two types of 17O signals that are observed arise from the coordinated and remote oxygen atoms of the sulfite ligand. A typical five-coordinate Mo(V) site is compatible with the observed and calculated EPR parameters. PMID:22225516

  6. Existence of aa3-type ubiquinol oxidase as a terminal oxidase in sulfite oxidation of Acidithiobacillus thiooxidans.

    PubMed

    Sugio, Tsuyoshi; Hisazumi, Tomohiro; Kanao, Tadayoshi; Kamimura, Kazuo; Takeuchi, Fumiaki; Negishi, Atsunori

    2006-07-01

    It was found that Acidithiobacillus thiooxidans has sulfite:ubiquinone oxidoreductase and ubiquinol oxidase activities in the cells. Ubiquinol oxidase was purified from plasma membranes of strain NB1-3 in a nearly homogeneous state. A purified enzyme showed absorption peaks at 419 and 595 nm in the oxidized form and at 442 and 605 nm in the reduced form. Pyridine ferrohaemochrome prepared from the enzyme showed an alpha-peak characteristic of haem a at 587 nm, indicating that the enzyme contains haem a as a component. The CO difference spectrum of ubiquinol oxidase showed two peaks at 428 nm and 595 nm, and a trough at 446 nm, suggesting the existence of an aa(3)-type cytochrome in the enzyme. Ubiquinol oxidase was composed of three subunits with apparent molecular masses of 57 kDa, 34 kDa, and 23 kDa. The optimum pH and temperature for ubiquinol oxidation were pH 6.0 and 30 degrees C. The activity was completely inhibited by sodium cyanide at 1.0 mM. In contrast, the activity was inhibited weakly by antimycin A(1) and myxothiazol, which are inhibitors of mitochondrial bc(1) complex. Quinone analog 2-heptyl-4-hydoroxyquinoline N-oxide (HOQNO) strongly inhibited ubiquinol oxidase activity. Nickel and tungstate (0.1 mM), which are used as a bacteriostatic agent for A. thiooxidans-dependent concrete corrosion, inhibited ubiquinol oxidase activity 100 and 70% respectively.

  7. Isolation and characterization of a resident tolerant Saccharomyces cerevisiae strain from a spent sulfite liquor fermentation plant

    PubMed Central

    2012-01-01

    Spent Sulfite Liquor (SSL) from wood pulping facilities is a sugar rich effluent that can be used as feedstock for ethanol production. However, depending on the pulping process conditions, the release of monosaccharides also generates a range of compounds that negatively affect microbial fermentation. In the present study, we investigated whether endogenous yeasts in SSL-based ethanol plant could represent a source of Saccharomyces cerevisiae strains with a naturally acquired tolerance towards this inhibitory environment. Two isolation processes were performed, before and after the re-inoculation of the plant with a commercial baker’s yeast strain. The isolates were clustered by DNA fingerprinting and a recurrent Saccharomyces cerevisiae strain, different from the inoculated commercial baker’s yeast strain, was isolated. The strain, named TMB3720, flocculated heavily and presented high furaldehyde reductase activity. During fermentation of undiluted SSL, TMB3720 displayed a 4-fold higher ethanol production rate and 1.8-fold higher ethanol yield as compared to the commercial baker’s yeast. Another non-Saccharomyces cerevisiae species, identified as the pentose utilizing Pichia galeiformis, was also recovered in the last tanks of the process where the hexose to pentose sugar ratio and the inhibitory pressure are expected to be the lowest. PMID:23237549

  8. C-Terminal Region of Sulfite Reductase Is Important to Localize to Chloroplast Nucleoids in Land Plants.

    PubMed

    Kobayashi, Yusuke; Otani, Takuto; Ishibashi, Kota; Shikanai, Toshiharu; Nishimura, Yoshiki

    2016-01-01

    Chloroplast (cp) DNA is compacted into cpDNA-protein complexes, called cp nucleoids. An abundant and extensively studied component of cp nucleoids is the bifunctional protein sulfite reductase (SiR). The preconceived role of SiR as the core cp nucleoid protein, however, is becoming less likely because of the recent findings that SiRs do not associate with cp nucleoids in some plant species, such as Zea mays and Arabidopsis thaliana To address this discrepancy, we have performed a detailed phylogenetic analysis of SiRs, which shows that cp nucleoid-type SiRs share conserved C-terminally encoded peptides (CEPs). The CEPs are likely to form a bacterial ribbon-helix-helix DNA-binding motif, implying a potential role in attaching SiRs onto cp nucleoids. A proof-of-concept experiment was conducted by fusing the nonnucleoid-type SiR from A. thaliana (AtSiR) with the CEP from the cp nucleoid-type SiR of Phaseolus vulgaris The addition of the CEP drastically altered the intra-cp localization of AtSiR to cp nucleoids. Our analysis supports the possible functions of CEPs in determining the localization of SiRs to cp nucleoids and illuminates a possible evolutionary scenario for SiR as a cp nucleoid protein. PMID:27189994

  9. Batch slurry photocatalytic reactors for the generation of hydrogen from sulfide and sulfite waste streams under solar irradiation

    SciTech Connect

    Priya, R.; Kanmani, S.

    2009-10-15

    In this study, two solar slurry photocatalytic reactors i.e., batch reactor (BR) and batch recycle reactor with continuous supply of inert gas (BRRwCG) were developed for comparing their performance. The performance of the photocatalytic reactors were evaluated based on the generation of hydrogen (H{sub 2}) from water containing sodium sulfide (Na{sub 2}S) and sodium sulfite (Na{sub 2}SO{sub 3}) ions. The photoreactor of capacity 300 mL was developed with UV-vis transparent walls. The catalytic powders ((CdS/ZnS)/Ag{sub 2}S + (RuO{sub 2}/TiO{sub 2})) were kept suspended by means of magnetic stirrer in the BR and gas bubbling and recycling of the suspension in the BRRwCG. The rate constant was found to be 120.86 (einstein{sup -1}) for the BRRwCG whereas, for the BR it was found to be only 10.92 (einstein{sup -1}). The higher rate constant was due to the fast desorption of products and suppression of e{sup -}/h{sup +} recombination. (author)

  10. Optimization of alkaline sulfite pretreatment and comparative study with sodium hydroxide pretreatment for improving enzymatic digestibility of corn stover.

    PubMed

    Liu, Huan; Pang, Bo; Wang, Haisong; Li, Haiming; Lu, Jie; Niu, Meihong

    2015-04-01

    In this study, alkaline sulfite pretreatment of corn stover was optimized. The influences of pretreatments on solid yield, delignification, and carbohydrate recovery under different pretreatment conditions and subsequent enzymatic hydrolysis were investigated. The effect of pretreatment was evaluated by enzymatic hydrolysis efficiency and the total sugar yield. The optimum pretreatment conditions were obtained, as follows: the total titratable alkali (TTA) of 12%, liquid/solid ratio of 6:1, temperature of 140 °C, and holding time of 20 min. Under those conditions, the solid yield was 55.24%, and the removal of lignin was 82.68%. Enzymatic hydrolysis rates of glucan and xylan for pretreated corn stover were 85.38% and 70.36%, and the total sugar yield was 74.73% at cellulase loading of 20 FPU/g and β-glucosidase loading of 10 IU/g for 48 h. Compared with sodium hydroxide pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 10.43%. Additionally, the corn stover pretreated under the optimum pretreatment conditions was beaten by PFI at 1500 revolutions. After beating, enzymatic hydrolysis rates of glucan and xylan were 89.74% and 74.06%, and the total sugar yield was 78.58% at the same enzymatic hydrolysis conditions. Compared with 1500 rpm of PFI beating after sodium pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 14.05%. PMID:25773993

  11. Determination of Histamine by High-Performance Liquid Chromatography After Precolumn Derivatization with o-Phthalaldehyde-Sulfite.

    PubMed

    Chen, Rongxiang; Deng, Yinghua; Yang, Liu; Wang, Jie; Xu, Fuqiang

    2016-04-01

    A fast and sensitive method was developed for in vivo determination of histamine in the brain microdialysate by reverse ion pair chromatography with electrochemical detection. The microdialysates were derivatized with o-phthalaldehyde and sodium sulfite, and separation was achieved using isocratic elution within 10 min. The separation was performed in an Agilent Eclipse Plus C18 column (3.0 × 150 mm, particle size 3.5 μm), and the mobile phase consisted of 100 mM monosodium phosphate (pH 6.0), 500 mg L(-1) OSA and 20% methanol (v/v). The linearity (R(2)) was found to be >0.999, with a range from 2 to 50 nM and excellent repeatability (relative standard deviation, 2.29-6.04%), and the limit of detection was 0.4 nM. This method was successfully applied to analyze the extracellular concentration of histamine in the hypothalamus of rats, with probe recovery calculated in vivo. PMID:26688564

  12. Kinetics of the oxidation of hydrogen sulfite by hydrogen peroxide in aqueous solution:. ionic strength effects and temperature dependence

    NASA Astrophysics Data System (ADS)

    Maaß, Frank; Elias, Horst; Wannowius, Klaus J.

    Conductometry was used to study the kinetics of the oxidation of hydrogen sulfite, HSO -3, by hydrogen peroxide in aqueous non-buffered solution at the low concentration level of 10 -5-10 -6 M, typically found in cloud water. The kinetic data confirm that the rate law reported for the pH range 3-6 at higher concentration levels, rate= kH·[H +]·[HSO -3]·[H 2O 2], is valid at the low concentration level and at low ionic strength Ic. At 298 K and Ic=1.5×10 -4 M, third-order rate constant kH was found to be kH=(9.1±0.5)×10 7 M -2 s -1. The temperature dependence of kH led to an activation energy of Ea=29.7±0.9 kJ mol -1. The effect of the ionic strength (adjusted with NaCl) on rate constant kH was studied in the range Ic=2×10 -4-5.0 M at pH=4.5-5.2 by conductometry and stopped-flow spectrophotometry. The dependence of kH on Ic can be described with a semi-empirical relationship, which is useful for the purpose of comparison and extrapolation. The kinetic data obtained are critically compared with those reported earlier.

  13. A combined adsorption and flocculation process for producing lignocellulosic complexes from spent liquors of neutral sulfite semichemical pulping process.

    PubMed

    Dashtban, Mehdi; Gilbert, Allan; Fatehi, Pedram

    2014-05-01

    The spent liquor (SL) of a neutral sulfite semichemical pulping process contains lignocelluloses that are currently treated in a waste water system. In this work, an adsorption process using activated carbon (AC) was considered for isolating the lignin and hemicelluloses from SL. The maximum adsorptions of 0.9 g/g lignin and 0.43 g/g of hemicelluloses on AC were achieved under the conditions of 30°C, pH 7 and 3h with SL/AC weight ratio of 90. The addition of polydiallyldimethylammonium chloride (PDADMAC) to the SL/AC system significantly improved the adsorption of lignin to 2.5 g/g on AC. The molecular weight of PDADMAC considerably affected the results in that the higher MW PDADMAC led to less lignin, but more hemicelluloses, turbidity and chemical oxygen demand removals from the SL. The thermal analysis also revealed that the higher MW PDADMAC generated precipitates with a lower incineration temperature and heating value. PMID:24675396

  14. Optimization of alkaline sulfite pretreatment and comparative study with sodium hydroxide pretreatment for improving enzymatic digestibility of corn stover.

    PubMed

    Liu, Huan; Pang, Bo; Wang, Haisong; Li, Haiming; Lu, Jie; Niu, Meihong

    2015-04-01

    In this study, alkaline sulfite pretreatment of corn stover was optimized. The influences of pretreatments on solid yield, delignification, and carbohydrate recovery under different pretreatment conditions and subsequent enzymatic hydrolysis were investigated. The effect of pretreatment was evaluated by enzymatic hydrolysis efficiency and the total sugar yield. The optimum pretreatment conditions were obtained, as follows: the total titratable alkali (TTA) of 12%, liquid/solid ratio of 6:1, temperature of 140 °C, and holding time of 20 min. Under those conditions, the solid yield was 55.24%, and the removal of lignin was 82.68%. Enzymatic hydrolysis rates of glucan and xylan for pretreated corn stover were 85.38% and 70.36%, and the total sugar yield was 74.73% at cellulase loading of 20 FPU/g and β-glucosidase loading of 10 IU/g for 48 h. Compared with sodium hydroxide pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 10.43%. Additionally, the corn stover pretreated under the optimum pretreatment conditions was beaten by PFI at 1500 revolutions. After beating, enzymatic hydrolysis rates of glucan and xylan were 89.74% and 74.06%, and the total sugar yield was 78.58% at the same enzymatic hydrolysis conditions. Compared with 1500 rpm of PFI beating after sodium pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 14.05%.

  15. C-Terminal Region of Sulfite Reductase Is Important to Localize to Chloroplast Nucleoids in Land Plants

    PubMed Central

    Kobayashi, Yusuke; Otani, Takuto; Ishibashi, Kota; Shikanai, Toshiharu; Nishimura, Yoshiki

    2016-01-01

    Chloroplast (cp) DNA is compacted into cpDNA-protein complexes, called cp nucleoids. An abundant and extensively studied component of cp nucleoids is the bifunctional protein sulfite reductase (SiR). The preconceived role of SiR as the core cp nucleoid protein, however, is becoming less likely because of the recent findings that SiRs do not associate with cp nucleoids in some plant species, such as Zea mays and Arabidopsis thaliana. To address this discrepancy, we have performed a detailed phylogenetic analysis of SiRs, which shows that cp nucleoid-type SiRs share conserved C-terminally encoded peptides (CEPs). The CEPs are likely to form a bacterial ribbon–helix–helix DNA-binding motif, implying a potential role in attaching SiRs onto cp nucleoids. A proof-of-concept experiment was conducted by fusing the nonnucleoid-type SiR from A. thaliana (AtSiR) with the CEP from the cp nucleoid-type SiR of Phaseolus vulgaris. The addition of the CEP drastically altered the intra-cp localization of AtSiR to cp nucleoids. Our analysis supports the possible functions of CEPs in determining the localization of SiRs to cp nucleoids and illuminates a possible evolutionary scenario for SiR as a cp nucleoid protein. PMID:27189994

  16. pH-oscillations in the bromate–sulfite reaction in semibatch and in gel-fed batch reactors

    SciTech Connect

    Poros, Eszter; Kurin-Csörgei, Krisztina; Szalai, István; Orbán, Miklós; Rábai, Gyula

    2015-06-15

    The simplest bromate oxidation based pH-oscillator, the two component BrO{sub 3}{sup −}–SO{sub 3}{sup 2–} flow system was transformed to operate under semibatch and closed arrangements. The experimental preconditions of the pH-oscillations in semibatch configuration were predicted by model calculations. Using this information as guideline large amplitude (ΔpH∼3), long lasting (11–24 h) pH-oscillations accompanied with only a 20% increase of the volume in the reactor were measured when a mixture of Na{sub 2}SO{sub 3} and H{sub 2}SO{sub 4} was pumped into the solution of BrO{sub 3}{sup −} with a very low rate. Batch-like pH-oscillations, similar in amplitude and period time appeared when the sulfite supply was substituted by its dissolution from a gel layer prepared previously in the reactor in presence of high concentration of Na{sub 2}SO{sub 3}. The dissolution vs time curve and the pH-oscillations in the semibatch and closed systems were successfully simulated. Due to the simplicity in composition and in experimental technique, the semibatch and batch-like BrO{sub 3}{sup −}–SO{sub 3}{sup 2–} pH-oscillators may become superior to their CSTR (continuous flow stirred tank reactor) version in some present and future applications.

  17. pH-oscillations in the bromate-sulfite reaction in semibatch and in gel-fed batch reactors

    NASA Astrophysics Data System (ADS)

    Poros, Eszter; Kurin-Csörgei, Krisztina; Szalai, István; Rábai, Gyula; Orbán, Miklós

    2015-06-01

    The simplest bromate oxidation based pH-oscillator, the two component BrO3--SO32- flow system was transformed to operate under semibatch and closed arrangements. The experimental preconditions of the pH-oscillations in semibatch configuration were predicted by model calculations. Using this information as guideline large amplitude (ΔpH˜3), long lasting (11-24 h) pH-oscillations accompanied with only a 20% increase of the volume in the reactor were measured when a mixture of Na2SO3 and H2SO4 was pumped into the solution of BrO3- with a very low rate. Batch-like pH-oscillations, similar in amplitude and period time appeared when the sulfite supply was substituted by its dissolution from a gel layer prepared previously in the reactor in presence of high concentration of Na2SO3. The dissolution vs time curve and the pH-oscillations in the semibatch and closed systems were successfully simulated. Due to the simplicity in composition and in experimental technique, the semibatch and batch-like BrO3--SO32- pH-oscillators may become superior to their CSTR (continuous flow stirred tank reactor) version in some present and future applications.

  18. Development of xylose-fermenting yeasts for ethanol production at high acetic acid concentrations

    SciTech Connect

    Mohandas, D.V.; Whelan, D.R.; Panchal, C.J.

    1995-12-31

    Mutants resistant to comparatively high levels of acetic acid were isolated from the xylose-fermenting yeasts Candida shehatae and Pichia Stipitis by adapting these cultures to increasing concentrations of acetic acid grown in shake-flask cultures. These mutants were tested for their ability to ferment xylose in presence of high acetic acid concentrations, in acid hydrolysates of wood, and in hardwood spent sulfite liquor, and compared with their wild-type counterparts and between themselves. The P. stipitis mutant exhibited faster fermentation times, better tolerance to acid hydrolysates, and tolerance to lower pH.

  19. Theoretical and Experimental Studies of the Spin Trapping of Inorganic Radicals by 5,5-Dimethyl-1-Pyrroline N-Oxide (DMPO). 3. Sulfur Dioxide, Sulfite and Sulfate Radical Anions

    PubMed Central

    Zamora, Pedro L.; Villamena, Frederick A.

    2012-01-01

    Radical forms of sulfur dioxide (SO2), sulfite (SO32−), sulfate (SO42−), and their conjugate acids are known to be generated in vivo through various chemical and biochemical pathways. Oxides of sulfur are environmentally pervasive compounds and are associated with a number of health problems. There is growing evidence that their toxicity may be mediated by their radical forms. Electron paramagnetic resonance (EPR) spin trapping using the commonly used spin trap, 5,5-dimethyl-1-pyrroline N-oxide (DMPO), has been employed in the detection of SO3•− and SO4•−. The thermochemistries of SO2•−, SO3•−, SO4•−, and their respective conjugate acids addition to DMPO were predicted using density functional theory (DFT) at the PCM/B3LYP/6-31+G**//B3LYP/6-31G* level. No spin adduct was observed for SO2•− by EPR but an S-centered adduct was observed for SO3•− and an O-centered adduct for SO4•−. Determination of adducts as S- or O-centered was made via comparison based on qualitative trends of experimental hfcc’s with theoretically calculated ones. The thermodynamics of the non-radical addition of SO32− and HSO3− to DMPO followed by conversion to the corresponding radical adduct via the Forrester-Hepburn mechanism was also calculated. Adduct acidities and decomposition pathways were investigated as well, including an EPR experiment using H217O to determine the site of hydrolysis of O-centered adducts. The mode of radical addition to DMPO is predicted to be governed by several factors, including spin population density, and geometries stabilized by hydrogen bonds. The thermodynamic data supports evidence for the radical addition pathway over the nucleophilic addition mechanism. PMID:22668066

  20. Regeneration of absorbents used for purifying effluent gases from acidic components

    SciTech Connect

    Gladkii, A.V.; Ivanina, I.N.

    1982-09-20

    The purpose of this report was to study the equilibrium conditions for the interaction between sodium sulfate and the calcium salts of various carboxylic acids. The experimental data presented can be recommended for engineering calculations for the regeneration of spent absorbent containing sodium sulfate or a mixture of sodium sulfate, sulfite, phosphate, and fluoride in various combinations, since, as previously shown, the equilibrium constants for the reaction between sodium sulfite, phosphate, or fluoride and calcium hydroxide or calcium carboxylate are large and thus an absorbent with these components is almost completely regenerated. The present data can be used for planning and putting into effect the purification of gases from acidic components in various branches of industry.

  1. Fermentation Kinetics for Xylitol Production by a Pichia stipitis d-Xylulokinase Mutant Previously Grown in Spent Sulfite Liquor

    NASA Astrophysics Data System (ADS)

    Rodrigues, Rita C. L. B.; Lu, Chenfeng; Lin, Bernice; Jeffries, Thomas W.

    Spent sulfite pulping liquor (SSL) contains lignin, which is present as lignosulfonate, and hemicelluloses that are present as hydrolyzed carbohydrates. To reduce the biological oxygen demand of SSL associated with dissolved sugars, we studied the capacity of Pichia stipitis FPL-YS30 (xyl3Δ) to convert these sugars into useful products. FPL-YS30 produces a negligible amount of ethanol while converting xylose into xylitol. This work describes the xylose fermentation kinetics of yeast strain P.stipitis FPL-YS30. Yeast was grown in rich medium supplemented with different carbon sources: glucose, xylose, or ammonia-base SSL. The SSL and glucose-acclimatized cells showed similar maximum specific growth rates (0.146 h-1). The highest xylose consumption at the beginning of the fermentation process occurred using cells precultivated in xylose, which showed relatively high specific activity of glucose-6-phosphate dehydrogenase (EC 1.1.1.49). However, the maximum specific rates of xylose consumption (0.19 gxylose/gcel h) and xylitol production (0.059 gxylitol/gcel h) were obtained with cells acclimatized in glucose, in which the ratio between xylose reductase (EC 1.1.1.21) and xylitol dehydrogenase (EC 1.1.1.9) was kept at higher level (0.82). In this case, xylitol production (31.6 g/l) was 19 and 8% higher than in SSL and xylose-acclimatized cells, respectively. Maximum glycerol (6.26 g/l) and arabitol (0.206 g/l) production were obtained using SSL and xylose-acclimatized cells, respectively. The medium composition used for the yeast precultivation directly reflected their xylose fermentation performance. The SSL could be used as a carbon source for cell production. However, the inoculum condition to obtain a high cell concentration in SSL needs to be optimized.

  2. Investigation of a novel ternary electrolyte based on dimethyl sulfite and lithium difluoromono(oxalato)borate for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Chen, Renjie; Zhu, Lu; Wu, Feng; Li, Li; Zhang, Rong; Chen, Shi

    2014-01-01

    Lithium difluoromono(oxalato)borate (LiODFB) has been used as a novel lithium salt for battery in recent studies. In this study, a series of novel electrolytes has been prepared by adding 30 vol% dimethyl sulfite (DMS) or dimethyl carbonate (DMC) as co-solvent into an ethylene carbonate (EC)/ethyl methyl carbonate (EMC) + LiX mixture, in which the LiX could be LiClO4, LiODFB, LiBOB, LiTFSI, or LiCF3SO3. These ternary electrolytes have been investigated for use in lithium ion batteries. FT-IR spectroscopy analysis shows that characteristic functional groups (-CO3, -SO3) undergo red-shift or blue-shift with the addition of different lithium salts. The LiODFB-EC/EMC/DMS electrolyte exhibits high ionic conductivity, which is mainly because of the low melting point of DMS, and LiODFB possessing high solubility. The Li/MCMB cells containing this novel electrolyte exhibit high capacities, good cycling performance, and excellent rate performance. These performances are probably because both LiODFB and DMS can assist in the formation of SEI films by reductive decomposition. Additionally, the discharge capacity of Li/LiCoO2 half cell containing LiODFB-EC/EMC/DMS electrolyte is 130.9 mAh g-1 after 50 cycles, and it is very comparable with the standard-commercial electrolyte. The results show that this study produces a promising electrolyte candidate for lithium ion batteries.

  3. Community composition and distribution of sulfate- and sulfite-reducing prokaryotes in sediments from the Changjiang estuary and adjacent East China Sea

    NASA Astrophysics Data System (ADS)

    He, Hui; Zhen, Yu; Mi, Tiezhu; Xu, Bochao; Wang, Guoshan; Zhang, Yu; Yu, Zhigang

    2015-11-01

    Sulfate- and sulfite-reducing prokaryotes (SSRP) communities play a vital role in both sulfur and carbon cycles. Community composition and abundance of SSRP were investigated using dissimilatory sulfite reductase β subunit (dsrB) gene sequencing in sediments from the Changjiang estuary and its adjacent area in the East China Sea (ECS). Clone libraries were constructed and real-time fluorescence quantitative polymerase chain reaction (qPCR) was applied to understand the community information of SSRP. In addition to sequences affiliated to sulfate-reducing prokaryotes (SRP), those affiliated with sulfite-reducing prokaryotes (SiRP) were also observed. Four phylotypes of SRP in this study showed genetic similarity to Desulfobulbaceae, Syntrophobacteraceae, Desulfobacteraceae and Peptococcaceae, and an unknown group that could not be clearly affiliated with known lineages was found. Salinity, temperature and contents of total organic carbon (TOC) were most closely correlated with the SSRP communities by canonical correspondence analysis (CCA). 210Pb activities demonstrated the sedimentary environment at S33 was more stable than that at S31. Intense resuspension and reconstruction of sediments made the vertical abundance profile of SSRP fluctuate violently. For surface sediments, the dsrB gene copy numbers near the Changjiang estuary were higher than those in the mouth of Hangzhou Bay and the mud deposits along the Zhejiang coast, and contents of TOC were positively related to the copy numbers of dsrB gene. Our data provided valuable information to achieve a better understanding of the potential role of SSRP in sediments from the Changjiang estuary and adjacent East China Sea.

  4. Characterization of chloride-depleted human sulfite oxidase by EPR spectroscopy: experimental evidence for the role of anions in product release

    PubMed Central

    Rajapakshe, Asha; Johnson-Winters, Kayunta; Nordstrom, Anna R.; Meyers, Kimberly T.; Emesh, Safia; Astashkin, Andrei V.; Enemark, John H.

    2010-01-01

    The Mo(V) state of the molybdoenzyme sulfite oxidase (SO) is paramagnetic and can be studied by electron paramagnetic resonance (EPR) spectroscopy. Vertebrate SO at pH < 7 and pH > 9 exhibits characteristic EPR spectra that correspond to two structurally different forms of the Mo(V) active center referred to as the low-pH (lpH) and high-pH (hpH) forms, respectively. Both EPR forms have an exchangeable equatorial OH ligand, but its orientation in the two forms is different. It has been hypothesized that the formation of the lpH species is dependent upon the presence of chloride. In this work we have prepared and purified samples of wild type and various mutants of human SO that are depleted in chloride. These samples do not exhibit the typical lpH EPR spectrum at low pH, but rather show spectra that are characteristic of the blocked species that contains an exchangeable equatorial sulfate ligand. Addition of chloride to these samples results in the disappearance of the blocked species and the formation of the lpH species. Similarly, if chloride is added before sulfite, the lpH species is formed instead of the blocked one. Qualitatively similar results were observed for samples of sulfite oxidizing enzymes from other organisms that were previously reported to form a blocked species at low pH. However, the depletion of chloride has no effect upon the formation of the hpH species. PMID:20491442

  5. Processes to remove acid forming gases from exhaust gases

    DOEpatents

    Chang, S.G.

    1994-09-20

    The present invention relates to a process for reducing the concentration of NO in a gas, which process comprises: (A) contacting a gas sample containing NO with a gaseous oxidizing agent to oxidize the NO to NO[sub 2]; (B) contacting the gas sample of step (A) comprising NO[sub 2] with an aqueous reagent of bisulfite/sulfite and a compound selected from urea, sulfamic acid, hydrazinium ion, hydrazoic acid, nitroaniline, sulfanilamide, sulfanilic acid, mercaptopropanoic acid, mercaptosuccinic acid, cysteine or combinations thereof at between about 0 and 100 C at a pH of between about 1 and 7 for between about 0.01 and 60 sec; and (C) optionally contacting the reaction product of step (A) with conventional chemical reagents to reduce the concentrations of the organic products of the reaction in step (B) to environmentally acceptable levels. Urea or sulfamic acid are preferred, especially sulfamic acid, and step (C) is not necessary or performed. 16 figs.

  6. Quantitative Microbiological Analysis of Bacterial Community Shifts in a High-Rate Anaerobic Bioreactor Treating Sulfite Evaporator Condensate

    PubMed Central

    Ney, U.; Macario, A. J. L.; de Macario, E. Conway; Aivasidis, A.; Schoberth, S. M.; Sahm, H.

    1990-01-01

    The bacterial population of a high-rate, anaerobic, fixed-bed loop reactor treating sulfite evaporator condensate from the pulp industry was studied over a 14-month period. This period was divided into seven cycles that included a startup at the beginning of each cycle. Some 82% of the total biomass was immobilized on and between the porous glass rings filling the reactor. The range of the total number of microorganisms in these biofilms was 2 × 109 to 7 × 109 cells per ml. Enumeration and characterization by microbiological methods and by phase-contrast, epifluorescence, and electron microscopy showed that the samples consisted mainly of the following methanogens: a Methanobacterium sp., a Methanosarcina sp., a Methanobrevibacter sp., and a Methanothrix sp., as well as furfural-degrading sulfate-reducing bacteria resembling Desulfovibrio furfuralis. Viable counts of hydrogenotrophic methanogens were relatively stable (mostly within the range of 3.2 × 108 to 7.5 × 108 cells per ml), but Methanobrevibacter cells increased from <5 to 30% of the total hydrogenotrophic count after transfer of the fixed bed into a second reactor vessel. Acetotrophic methanogens reached their highest numbers of 1.3 × 108 to 2.6 × 108 cells per ml in the last fermentation cycles. They showed a morphological shift from sarcinalike packets in early samples to single coccoid forms in later phases of the fermentation. Furfural-degrading sulfate reducers reached counts of 1 × 107 to 5.8 × 107 cells per ml. The distribution of the chief metabolic groups between free fluid and biofilms was analyzed in the fifth fermentation cycle: 4.5 times more furfural degraders were found in the free fluid than in the biofilms. In contrast, 5.8 times more acetotrophic and 16.6 times more hydrogenotrophic methanogens were found in the biofilms than in the free liquid. The data concerning time shifts of morphotypes among the trophic groups of methanogens corroborated the trends observed by using

  7. Quantitative microbiological analysis of bacterial community shifts in a high-rate anaerobic bioreactor treating sulfite evaporator condensate.

    PubMed

    Ney, U; Macario, A J; Conway de Macario, E; Aivasidis, A; Schoberth, S M; Sahm, H

    1990-08-01

    The bacterial population of a high-rate, anaerobic, fixed-bed loop reactor treating sulfite evaporator condensate from the pulp industry was studied over a 14-month period. This period was divided into seven cycles that included a startup at the beginning of each cycle. Some 82% of the total biomass was immobilized on and between the porous glass rings filling the reactor. The range of the total number of microorganisms in these biofilms was 2 x 10 to 7 x 10 cells per ml. Enumeration and characterization by microbiological methods and by phase-contrast, epifluorescence, and electron microscopy showed that the samples consisted mainly of the following methanogens: a Methanobacterium sp., a Methanosarcina sp., a Methanobrevibacter sp., and a Methanothrix sp., as well as furfural-degrading sulfate-reducing bacteria resembling Desulfovibrio furfuralis. Viable counts of hydrogenotrophic methanogens were relatively stable (mostly within the range of 3.2 x 10 to 7.5 x 10 cells per ml), but Methanobrevibacter cells increased from <5 to 30% of the total hydrogenotrophic count after transfer of the fixed bed into a second reactor vessel. Acetotrophic methanogens reached their highest numbers of 1.3 x 10 to 2.6 x 10 cells per ml in the last fermentation cycles. They showed a morphological shift from sarcinalike packets in early samples to single coccoid forms in later phases of the fermentation. Furfural-degrading sulfate reducers reached counts of 1 x 10 to 5.8 x 10 cells per ml. The distribution of the chief metabolic groups between free fluid and biofilms was analyzed in the fifth fermentation cycle: 4.5 times more furfural degraders were found in the free fluid than in the biofilms. In contrast, 5.8 times more acetotrophic and 16.6 times more hydrogenotrophic methanogens were found in the biofilms than in the free liquid. The data concerning time shifts of morphotypes among the trophic groups of methanogens corroborated the trends observed by using immunological assays on

  8. Studies on the bioavailability of deoxynivalenol (DON) and DON sulfonate (DONS) 1, 2, and 3 in pigs fed with sodium sulfite-treated DON-contaminated maize.

    PubMed

    Paulick, Marleen; Winkler, Janine; Kersten, Susanne; Schatzmayr, Dian; Schwartz-Zimmermann, Heidi Elisabeth; Dänicke, Sven

    2015-11-01

    Deoxynivalenol (DON) exposure of pigs might cause serious problems when critical dietary toxin concentrations are exceeded. As DON contamination of agricultural crops cannot be completely prevented, detoxification measures are needed. Wet preservation with sodium sulfite resulted in a significant DON reduction of naturally-contaminated maize in previous experiments. The preserved material had a characteristic DON sulfonates (DONS) pattern. DONS is known to be less toxic than DON but its stability was shown to depend on pH, which gives rise to the question if a back-conversion to DON occurs in vivo. Therefore, the toxicokinetics and bioavailability of DON and DONS were studied in pigs. After the administration of a single oral or intravenous bolus of DON or DONS, serial blood samples were collected and subsequently analyzed. DONS was not detectable after oral administration of DONS mixtures. The results showed further that the bioavailability of DONS as DON in pigs fed maize preserved wet with sodium sulfite was significantly decreased compared to untreated control maize (DON), indicating that DONS obviously did not convert back to DON to a large extent in vivo. Moreover, the fact that DONS was not detectable in systemic blood requires further investigations regarding their ingestive and/or metabolic fate. PMID:26556376

  9. Studies on the bioavailability of deoxynivalenol (DON) and DON sulfonate (DONS) 1, 2, and 3 in pigs fed with sodium sulfite-treated DON-contaminated maize.

    PubMed

    Paulick, Marleen; Winkler, Janine; Kersten, Susanne; Schatzmayr, Dian; Schwartz-Zimmermann, Heidi Elisabeth; Dänicke, Sven

    2015-11-05

    Deoxynivalenol (DON) exposure of pigs might cause serious problems when critical dietary toxin concentrations are exceeded. As DON contamination of agricultural crops cannot be completely prevented, detoxification measures are needed. Wet preservation with sodium sulfite resulted in a significant DON reduction of naturally-contaminated maize in previous experiments. The preserved material had a characteristic DON sulfonates (DONS) pattern. DONS is known to be less toxic than DON but its stability was shown to depend on pH, which gives rise to the question if a back-conversion to DON occurs in vivo. Therefore, the toxicokinetics and bioavailability of DON and DONS were studied in pigs. After the administration of a single oral or intravenous bolus of DON or DONS, serial blood samples were collected and subsequently analyzed. DONS was not detectable after oral administration of DONS mixtures. The results showed further that the bioavailability of DONS as DON in pigs fed maize preserved wet with sodium sulfite was significantly decreased compared to untreated control maize (DON), indicating that DONS obviously did not convert back to DON to a large extent in vivo. Moreover, the fact that DONS was not detectable in systemic blood requires further investigations regarding their ingestive and/or metabolic fate.

  10. Studies on the Bioavailability of Deoxynivalenol (DON) and DON Sulfonate (DONS) 1, 2, and 3 in Pigs Fed with Sodium Sulfite-Treated DON-Contaminated Maize

    PubMed Central

    Paulick, Marleen; Winkler, Janine; Kersten, Susanne; Schatzmayr, Dian; Schwartz-Zimmermann, Heidi Elisabeth; Dänicke, Sven

    2015-01-01

    Deoxynivalenol (DON) exposure of pigs might cause serious problems when critical dietary toxin concentrations are exceeded. As DON contamination of agricultural crops cannot be completely prevented, detoxification measures are needed. Wet preservation with sodium sulfite resulted in a significant DON reduction of naturally-contaminated maize in previous experiments. The preserved material had a characteristic DON sulfonates (DONS) pattern. DONS is known to be less toxic than DON but its stability was shown to depend on pH, which gives rise to the question if a back-conversion to DON occurs in vivo. Therefore, the toxicokinetics and bioavailability of DON and DONS were studied in pigs. After the administration of a single oral or intravenous bolus of DON or DONS, serial blood samples were collected and subsequently analyzed. DONS was not detectable after oral administration of DONS mixtures. The results showed further that the bioavailability of DONS as DON in pigs fed maize preserved wet with sodium sulfite was significantly decreased compared to untreated control maize (DON), indicating that DONS obviously did not convert back to DON to a large extent in vivo. Moreover, the fact that DONS was not detectable in systemic blood requires further investigations regarding their ingestive and/or metabolic fate. PMID:26556376

  11. Indirect determination of sulfite using a polyphenol oxidase biosensor based on a glassy carbon electrode modified with multi-walled carbon nanotubes and gold nanoparticles within a poly(allylamine hydrochloride) film.

    PubMed

    Sartori, Elen Romão; Vicentini, Fernando Campanhã; Fatibello-Filho, Orlando

    2011-12-15

    The modification of a glassy carbon electrode with multi-walled carbon nanotubes and gold nanoparticles within a poly(allylamine hydrochloride) film for the development of a biosensor is proposed. This approach provides an efficient method used to immobilize polyphenol oxidase (PPO) obtained from the crude extract of sweet potato (Ipomoea batatas (L.) Lam.). The principle of the analytical method is based on the inhibitory effect of sulfite on the activity of PPO, in the reduction reaction of o-quinone to catechol and/or the reaction of o-quinone with sulfite. Under the optimum experimental conditions using the differential pulse voltammetry technique, the analytical curve obtained was linear in the concentration of sulfite in the range from 0.5 to 22 μmol L(-1) with a detection limit of 0.4 μmol L(-1). The biosensor was applied for the determination of sulfite in white and red wine samples with results in close agreement with those results obtained using a reference iodometric method (at a 95% confidence level). PMID:22099673

  12. Structural Studies of the Molybdenum Center of the Pathogenic R160Q Mutant of Human Sulfite Oxidase by Pulsed EPR Spectroscopy and 17O and 33S Labeling

    PubMed Central

    Astashkin, Andrei V.; Johnson-Winters, Kayunta; Klein, Eric L.; Feng, Changjian; Wilson, Heather L.; Rajagopalan, K. V.; Raitsimring, Arnold M.; Enemark, John H.

    2009-01-01

    Electron paramagnetic resonance (EPR) investigation of the Mo(V) center of the pathogenic R160Q mutant of human sulfite oxidase (hSO) confirms the presence of three distinct species whose relative abundances depend upon pH. Species 1 is exclusively present at pH ≤ 6, and remains in significant amounts even at pH 8. Variable-frequency electron spin echo envelope modulation (ESEEM) studies of this species prepared with 33S-labeled sulfite clearly show the presence of coordinated sulfate, as has previously been found for the “blocked” form of Arabidopsis thaliana at low pH (Astashkin, A. V.; Johnson-Winters, K.; Klein, E. L.; Byrne, R. S.; Hille, R.; Raitsimring, A. M.; Enemark, J. H. J. Am. Chem. Soc. 2007, 129, 14800). The ESEEM spectra of Species 1 prepared in 17O-enriched water show both strongly and weakly magnetically coupled 17O atoms that can be assigned to an equatorial sulfate ligand and the axial oxo ligand, respectively. The nuclear quadrupole interaction (nqi) of the axial oxo ligand is substantially stronger than those found for other oxo-Mo(V) centers studied previously. Additionally, pulsed electron–nuclear double resonance (ENDOR) measurements reveal a nearby weakly coupled exchangeable proton. The structure for Species 1 proposed from the pulsed EPR results using isotopic labeling is a six-coordinate Mo(V) center with an equatorial sulfate ligand that is hydrogen bonded to an exchangeable proton. Six-coordination is supported by the 17O nqi parameters for the axial oxo group of the model compound, (dttd)Mo17O(17Otms), where H2dttd = 2,3:8,9-dibenzo-1,4,7,10-tetrathiadecane; tms = trimethylsilyl. Reduction of R160Q to Mo(V) with Ti(III) gives primarily Species 2, another low pH form, whereas reduction with sulfite at higher pH values gives a mixture of Species 1 and 2, as well as the “primary” high pH form of wild-type SO. The occurrence of significant amounts of the “sulfate-blocked” form of R160Q (Species 1) at physiological p

  13. Isolation and Characterization of Methanesulfonic Acid-Degrading Bacteria from the Marine Environment

    PubMed Central

    Thompson, A. S.; Owens, N.; Murrell, J. C.

    1995-01-01

    Two methylotrophic bacterial strains, TR3 and PSCH4, capable of growth on methanesulfonic acid as the sole carbon source were isolated from the marine environment. Methanesulfonic acid metabolism in these strains was initiated by an inducible NADH-dependent monooxygenase, which cleaved methanesulfonic acid into formaldehyde and sulfite. The presence of hydroxypyruvate reductase and the absence of ribulose monophosphate-dependent hexulose monophosphate synthase indicated the presence of the serine pathway for formaldehyde assimilation. Cell suspensions of bacteria grown on methanesulfonic acid completely oxidized methanesulfonic acid to carbon dioxide and sulfite with a methanesulfonic acid/oxygen stoichiometry of 1.0:2.0. Oxygen electrode-substrate studies indicated the dissimilation of formaldehyde to formate and carbon dioxide for energy generation. Carbon dioxide was not fixed by ribulose bisphosphate carboxylase. It was shown that methanol is not an intermediate in methanesulfonic acid metabolism, although these strains grew on methanol and other one-carbon compounds, as well as a variety of heterotrophic carbon sources. These two novel marine facultative methylotrophs have the ability to mineralize methanesulfonic acid and may play a role in the cycling of global organic sulfur. PMID:16535055

  14. Recipe for new diorganostannates, [R2Sn(OS(O)2R1)4]2-, bearing alkanesulfonate groups using dialkyl sulfite as the reagent.

    PubMed

    Shankar, Ravi; Singh, Atul Pratap; Mahon, Mary F; Molloy, Kieran C; Hundal, Geeta; Biesemans, Monique; Willem, Rudolph

    2008-02-01

    A one-pot reaction between di-n-propyl/di-n-butyltin oxide, dialkyl sulfite, and triethylamine or tetra-n-alkylammonium iodide proceeds under ambient conditions (110-120 degrees C, 20 h) via sulfur-centered Arbuzov rearrangement to afford the corresponding dianionic tetraalkanesulfonato diorganostannates [R2Sn(OSO2Me)4].2Et3NMe [R = n-Pr (1), n-Bu (2)] as well as [n-Bu(2)Sn(OSO(2)R(1))(4)].(2)R(2)(4)N [R(1) = Me, Et, n-Pr; R(2) = Et (3, 5, and 7), n-Bu (4, 6, and 8)]. X-ray crystal structures of 2 and 3 reveal a monomeric motif of the dianion, with methanesulfonate groups acting as unidentate ligands. The (119)Sn NMR spectral studies suggest the existence of pentacoordinated tin species in solution.

  15. Evaluation of di(2,2,2-trifluoroethyl) sulfite as a film-forming additive on the MCMB anode of lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zheng, Xiangzhen; Wang, Wenguo; Huang, Tao; Fang, Guihuang; Pan, Ying; Wu, Maoxiang

    2016-10-01

    This study demonstrates a sulfur-based compound, di(2,2,2-trifluoroethyl) sulfite (DTFES), as a new solid electrolyte interphase (SEI) forming additive on mesocarbon microbeads (MCMB). When placed in the electrolyte, it can dramatically enhance the performance of lithium-ion batteries (LIBs). The capacity loss was significantly decreased from 17.4% to 6.3% after 100 charge-discharge cycles due to the addition of DTFES. Differential capacity (dQ/dV) versus voltage (V) analysis showed that DTFES was decomposed in advance versus to electrolyte solvents. The effects of DTFES were characterized by charge-discharge testing, electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). These results indicate that the SEI film formed on MCMB by DTFES plays an important role in LIBs performance. Their subsequent reaction pathways are proposed in the paper.

  16. The N-terminal Domain of Escherichia coli Assimilatory NADPH-Sulfite Reductase Hemoprotein Is an Oligomerization Domain That Mediates Holoenzyme Assembly*

    PubMed Central

    Askenasy, Isabel; Pennington, Joseph M.; Tao, Yeqing; Marshall, Alan G.; Young, Nicolas L.; Shang, Weifeng; Stroupe, M. Elizabeth

    2015-01-01

    Assimilatory NADPH-sulfite reductase (SiR) from Escherichia coli is a structurally complex oxidoreductase that catalyzes the six-electron reduction of sulfite to sulfide. Two subunits, one a flavin-binding flavoprotein (SiRFP, the α subunit) and the other an iron-containing hemoprotein (SiRHP, the β subunit), assemble to make a holoenzyme of about 800 kDa. How the two subunits assemble is not known. The iron-rich cofactors in SiRHP are unique because they are a covalent arrangement of a Fe4S4 cluster attached through a cysteine ligand to an iron-containing porphyrinoid called siroheme. The link between cofactor biogenesis and SiR stability is also ill-defined. By use of hydrogen/deuterium exchange and biochemical analysis, we show that the α8β4 SiR holoenzyme assembles through the N terminus of SiRHP and the NADPH binding domain of SiRFP. By use of small angle x-ray scattering, we explore the structure of the SiRHP N-terminal oligomerization domain. We also report a novel form of the hemoprotein that occurs in the absence of its cofactors. Apo-SiRHP forms a homotetramer, also dependent on its N terminus, that is unable to assemble with SiRFP. From these results, we propose that homotetramerization of apo-SiRHP serves as a quality control mechanism to prevent formation of inactive holoenzyme in the case of limiting cellular siroheme. PMID:26088143

  17. Measurement of neonatal equine immunoglobulins for assessment of colostral immunoglobulin transfer: comparison of single radial immunodiffusion with the zinc sulfate turbidity test, serum electrophoresis, refractometry for total serum protein, and the sodium sulfite precipitation test.

    PubMed

    Rumbaugh, G E; Ardans, A A; Ginno, D; Trommershausen-Smith, A

    1978-02-01

    Four procedures for assessment of adequacy of colostral immunoglobulin (Ig) transfer in foals were evaluated. Results of zinc sulfate turbidity test, serum electrophoresis, total serum protein refractometry, and sodium sulfite precipitation test were compared with immunoglobulin G content determined by single radial immunodiffusion. The zinc sulfate turbidity test gave acceptable results for IgG, except that hemolyzed serum samples gave higher than expected values. A correction factor for hemolyzed serum was found to be useful. Serum electrophoresis was a satisfactory method of estimating IgG content. Total serum protein values may not be a valid basis for estimating IgG content, inasmuch as postsuckling total protein values were found to decrease in some foals in which passive transfer of IgG had been adequate. Sodium sulfite precipitation reactions were too unpredictable to be of value for determination of neonatal IgG concentration.

  18. Effect of sulfite ions in N{sub 2} and CO{sub 2} purged 0.5 m NaCl solution on stainless steels examined by different electrochemical techniques and by reflectance measurements

    SciTech Connect

    Hemmingsen, T.; Aagotnes, N.O.; Kroeger-Silseth, T.; Kolak, N.; Kaik, M.

    1999-11-01

    Three steels, 13% Cr-steel, SS 304 steel and duplex steel are examined for corrosion for 48-hours periods in N{sub 2} or CO{sub 2} purged 0.5 M sodium chloride electrolytes with different sulfite concentrations. The results show that 13%Cr-steel is most susceptible to pitting in the presence of sulfite both under N{sub 2} and CO{sub 2} atmospheres. SS 304 steel was more resistant to corrosion than 13%Cr-steel. Duplex steel showed rather good corrosion resistance under these conditions. The corrosion rate, inclusive pitting corrosion, after 24 hours in presence of 0--10 mM sulfite based on LPR-measurements is for duplex steel 0.5--0.9 mm/year under N{sub 2} and 0.1--1.8 mm/year under CO{sub 2}, for SS 304 steel 1.0--1.8 mm/year under N{sub 2} and 0.6--1.4 mm/year under CO{sub 2}, and for 13%Cr-steel 1.3--2.2 mm/year under N{sub 2} and 0.7--1.8 mm/year under CO{sub 2}. The use of AC-impedance measurements is discussed. The method should be used with care when other mechanisms than general corrosion are involved.

  19. A study of electrochemically-induced corrosion of low carbon steel in a medium modelling acid rain

    NASA Astrophysics Data System (ADS)

    Vértes, Cs.; Lakatos-Varsányi, M.; Vértes, A.; Meisel, W.; Gütlich, P.

    1994-12-01

    Complementary electrochemical, spectrophotometric and electron microsopic investigations were made in addition to the conversion electron Mössbauer spectroscopic (CEMS) measurements to learn more about the mechanism of corrosion of low carbon steel samples in aqueous sulfate and sulfite containing sulfate solutions (pH 3.5, 6.5 and 8.5). Passivation of iron in pure sulfate solution was studied in detail in earlier papers. In the present work, we used a solution containing both sulfate and sulfite anions to obtain more information about the effect of acid rain on low carbon steel samples. The compositions and thicknesses of the passive films formed due to the electrochemical treatments were determined from the CEM spectra. γ-FeOOH was found in each case on the surface of the samples; nevertheless, at pH 3.5 the sextet belonging to Fe3C appears in the CEM spectra, and also FeSO4 · H2O was detected in low concentration after the shortest polarization time (90 min). The results of the applied methods proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6.5, while the measurements referred to suppressed pitting at pH 8.5.

  20. Direct Detection and Characterization of Chloride in the Active Site of the Low-pH Form of Sulfite Oxidase Using ESEEM Spectroscopy, Isotopic Labeling, and DFT Calculations

    PubMed Central

    Klein, Eric L.; Astashkin, Andrei V.; Ganyushin, Dmitry; Riplinger, Christoph; Johnson-Winters, Kayunta; Neese, Frank; Enemark, John H.

    2009-01-01

    Electron spin echo envelope modulation (ESEEM) investigations were carried out on samples of the low-pH (lpH) form of vertebrate sulfite oxidase (SO) prepared with 35Cl- and 37Cl-enriched buffers as well as with buffer containing the natural abundance of Cl isotopes. The isotope-related changes observed in the ESEEM spectra provide direct and unequivocal evidence that Cl− is located in close proximity to the Mo(V) center of lpH SO. The measured isotropic hyperfine interaction constant of about 4 MHz (35Cl) suggests that the Cl− ion is either weakly coordinated to Mo(V) at its otherwise vacant axial position, trans to the oxo ligand, or is hydrogen-bonded to the equatorial exchangeable OH ligand. Scalar relativistic all-electron density functional theory (DFT) calculations of the hyperfine and nuclear quadrupole interaction parameters, along with steric and energetic arguments, strongly support the possibility that Cl− is hydrogen-bonded to the equatorial OH ligand rather than being directly coordinated to the Mo(V). PMID:19402624

  1. Determination of the Distance between the Mo(V) and Fe(III) Heme Centers of Wild Type Human Sulfite Oxidase by Pulsed EPR Spectroscopy

    PubMed Central

    Astashkin, Andrei V.; Rajapakshe, Asha; Cornelison, Matthew; Johnson-Winters, Kayunta; Enemark, John H.

    2012-01-01

    Intramolecular electron transfer (IET) between the molybdenum and heme centers of vertebrate sulfite oxidase (SO) is proposed to be a key step in the catalytic cycle of the enzyme. However, the X-ray crystallographic distance between these centers, RMoFe = 32.3 Å, appears to be too long for the rapid IET rates observed in liquid solution. The Mo and heme domains are linked by a flexible tether, and it has been proposed that dynamic interdomain motion brings the two metal centers closer together and thereby facilitates rapid IET. To date there have been no direct distance measurements for SO in solution that would support or contradict this model. In this work, pulsed electron-electron double resonance (ELDOR) and relaxation induced dipolar modulation enhancement (RIDME) techniques were used to obtain information about RMoFe in the Mo(V)Fe(III) state of wild type recombinant human SO in frozen glassy solution. Surprisingly, the data obtained suggest a fixed structure with RMoFe = 32 Å, similar to that determined by X-ray crystallography for chicken SO, although the orientation of the RMoFe radius-vector with respect to the heme center was found to be somewhat different. The implications of these findings for the flexible tether model are discussed. PMID:22229742

  2. Instrumental methods of analysis of sulfur compounds in synfuel process streams. Quarterly technical progress report for April-June 1984. [Sulfidic, polysulfidic, thiosulfate, sulfite, sulfate, thiocyanate

    SciTech Connect

    Jordan, J.; Sexton, E.; Talbott, J.; Yakupkovic, J.

    1984-07-01

    Task 1: methods development for the speciation of the polysulfides. Work on this task has been completed in December 1983 and reported accordingly in DOE/PC/40783-T13. Task 2: methods development for the speciation of dithionite and polythionates. Electrochemical reduction of tetrathionate and pentathionate at the dropping mercury electrode (DME) proceeds through a mechanism involving specific adsorption of the reactant at the DME surface and yielding polarographic waves at -0.2 volt (versus the saturated calomel electrode) in aqueous solution. Ethanol interferes with the specific adsorption of tetrathionate and pentathionate in a range of potentials between 0.0 and -1.1 volt, because EtOH is preferentially adsorbed. This results in a shift of the polarographic half-wave potentials of tetrathionate and pentathionate, which facilitates their determination in polythionate mixtures. On the other hand, the polarographic reduction of trithionate is unaffected by ethanol, because it occurs at -1.5 volt where ethanol is not adsorbed at the surface of the DME. Task 3: total accounting of the sulfur balance in representative samples of synfuel process streams. Analyses of two aqueous gasifier effluents from Grand Forks, ND, were performed. An untreated specimen contained sulfidic and polysulfidic sulfur, thiosulfate and thiocyanate. On the other hand, sulfite, sulfate, and thiocyanate were the only sulfur moieties observed in the Grand Forks sample which had been stripped at PETC. 7 references, 1 figure, 3 tables.

  3. Development of a new analytical method for the determination of sulfites in fresh meats and shrimps by ion-exchange chromatography with conductivity detection.

    PubMed

    Iammarino, Marco; Di Taranto, Aurelia; Muscarella, Marilena; Nardiello, Donatella; Palermo, Carmen; Centonze, Diego

    2010-07-01

    An accurate and reliable analytical method, based on ion chromatography and suppressed conductivity detection, has been developed and validated for the quantitative determination of sulfites in fresh meats and shrimps. The chromatographic separation was accomplished by using an anion-exchange column eluted with sodium carbonate and sodium hydroxide. The optimized step-change elution, followed by column re-equilibration at the initial mobile phase composition, guaranteed a good resolution even toward endogenous interfering peaks, and an excellent retention time repeatability (1.1%, n=6). Good results in terms of sample extract stability, recovery efficiency were achieved with an extraction solvent mixture based on sodium hydroxide, fructose and EDTA. The method validation, performed by an in-house model according to Decision 657/2002/EC and Regulation 882/2004/EC, provided excellent results with respect to linearity (correlation coefficient up to 0.9998), limits of detection and quantification (2.7 and 8.2 mg kg(-1), respectively, expressed as SO(2)), expanded measurement uncertainty (below 10%), recovery values (ranging from 85% to 92%) and repeatability (down to 8%), demonstrating the conformity of the proposed method with the European directives. Finally, by major changes ruggedness studies, the method applicability to the quantitative analysis of cow hamburger, pork and horse sausage, and shrimps was demonstrated.

  4. Papillaes-enhanced hydrophobicity of large-sized polytetrafluoroethylene-polyphenylene sulfite soft film prepared by layer-by-layer construction

    NASA Astrophysics Data System (ADS)

    Hou, Cheng Cheng; Wang, Wen Jun; Zhang, Yu; Guan, Zi Sheng

    2012-07-01

    Large-sized superhydrophobic soft film with hierarchical structures were prepared by combining papillaes on the polytetrafluoroethylene-polyphenylene sulfite (PTFE-PPS) surface via layer-by-layer construction on the glass substrate and heat treatment processes, therein, the papillaes were formed by 0.1 μm PTFE coated on the pollen grains. The water contact angles (CAs) and sliding angles (SAs) of the films are strongly dependent on the number density of the papillaes on the PTFE-PPS surface. A superhydrophobic surface with a water CA = 151.5° and SA = 4° was obtained when the number density was about 649 mm-2. The papillaes with micro/submicroscale structures play an important role in the formation of the superhydrophobic surface and can change Wenzel-type surface into Cassie-Baxter-type surface. The condensation of water vapor on the Cassie-Baxter-type PTFE-PPS film is much more difficult than that of on the Wenzel-type film. Our method may develop into a facile method to prepare large-sized soft film with low cost, which limited only by the size of the loading substrates.

  5. Microbiological preservation of cucumbers for bulk storage using acetic acid and food preservatives.

    PubMed

    Pérez-Díaz, I M; McFeeters, R F

    2008-08-01

    Microbial growth did not occur when cucumbers were preserved without a thermal process by storage in solutions containing acetic acid, sodium benzoate, and calcium chloride to maintain tissue firmness. The concentrations of acetic acid and sodium benzoate required to ensure preservation were low enough so that stored cucumbers could be converted to the finished product without the need to wash out and discard excess acid or preservative. Since no thermal process was required, this method of preservation would be applicable for storing cucumbers in bulk containers. Acid tolerant pathogens died off in less than 24 h with the pH, acetic acid, and sodium benzoate concentrations required to assure the microbial stability of cucumbers stored at 30 degrees C. Potassium sorbate as a preservative in this application was not effective. Yeast growth was observed when sulfite was used as a preservative.

  6. Photoproduction of glyoxylic acid in model wine: Impact of sulfur dioxide, caffeic acid, pH and temperature.

    PubMed

    Grant-Preece, Paris; Schmidtke, Leigh M; Barril, Celia; Clark, Andrew C

    2017-01-15

    Glyoxylic acid is a tartaric acid degradation product formed in model wine solutions containing iron and its production is greatly increased by exposure to UV-visible light. In this study, the combined effect of sulfur dioxide, caffeic acid, pH and temperature on the light-induced (⩾300nm) production of glyoxylic acid in model wine containing tartaric acid and iron was investigated using a Box-Behnken experimental design and response surface methodology (RSM). Glyoxylic acid produced in the irradiated model wine was present in free and hydrogen sulfite adduct forms and the measured total, free and percentage free glyoxylic acid values were modeled using RSM. Sulfur dioxide significantly decreased the total amount of glyoxylic acid produced, but could not prevent its production, while caffeic acid showed no significant impact. The interaction between pH and temperature was significant, with low pH values and low temperatures giving rise to higher levels of total glyoxylic acid. PMID:27542478

  7. Impact of flue gas desulfurization-calcium sulfite and gypsum on soil microbial activity and wheat growth

    SciTech Connect

    Lee, Y.B.; Bigham, J.M.; Dick, W.A.; Kim, P.J.

    2008-08-15

    We conducted greenhouse tests to evaluate the effects of FGD-CaSO{sub 3} applied at rates of 0, 2.2, 4.4, and 8.8 Mg ha(-1) on wheat growth, soil enzyme activities, and the chemical properties of two soils with differing pH (4.0 vs. 6.2). A gypsum treatment applied at the rate of 2.2 Mg ha{sup -1} was used as a positive control. Exchangeable Ca{sup 2+} and water-extractable Ca{sup 2+} and SO{sub 4}{sup 2-} increased significantly with increasing FGD-CaSO{sub 3} application. SO{sub 4}{sup 2-} increased in both soils, indicating rapid oxidation of SO{sub 3}{sup 2-} to SO{sub 4}{sup 2-} when neither water nor oxygen was limiting. No changes in soil pH were measured. Applications of 2.2, 4.4, or 8.8 Mg CaSO{sub 3} ha{sup -1} to the pH 6.2 soil produced no effect on wheat growth or the uptake of N, P, Ca{sup 2+}, and Mg{sup 2+}. The uptake of SO{sub 4}{sup 2-} -S increased, whereas K uptake decreased. No significant differences in the activities of urease, {beta}-glucosidase, alkaline phosphatase, or arylsulfatase were observed relative to a control. In the acid soil, an application of 2.2 Mg ha{sup -1} FGD-CaSO{sub 3} increased wheat root growth and dry matter yield compared with an untreated control. The uptake of N, P, Ca{sup 2+}, and K{sup +} also increased presumably because of enhanced root development resulting from decreases in exchangeable Al{sup 3+} and increases in soluble Ca{sup 2+}. Wheat growth and alkaline phosphatase and arylsulfatase activities were significantly inhibited by addition of 8.8 Mg ha{sup -1} of FGD-CaSO{sub 3} compared with the untreated control or the same soil receiving 2.2 Mg ha{sup -1} gypsum. We conclude that surface applications of FGD-CaSO{sub 3} may be as effective as gypsum for inhibiting soil crusting, improving water infiltration, and promoting the movement of Ca{sup 2+} into acid subsoils. Moreover, application rates of equal to or less than 4.4 Mg ha-1 should have no negative impact on soil microbial activities or plant growth.

  8. Conformational gating of the dissimilatory sulfite reductase from Desulfovibrio vulgaris (Hildenborough). Synthesis, characterization, and stopped-flow kinetics studies of 1,5-IAEDANS-labeled desulfoviridin.

    PubMed

    Lui, S M; Cowan, J A

    1994-09-20

    The siroheme prosthetic center in the dissimilatory sulfite reductase (desulfoviridin) from Desulfovibrio vulgaris (Hildenborough) readily binds exogenous ligands in the reduced state, but it does not do so in the oxidized state. In contrast, free oxidized siroheme in solution is observed to bind ligands rapidly. This can only be explained by a structural barrier that precludes ligand binding to the enzyme in the oxidized state but is removed after reduction. These observations suggest a redox-linked structural transformation that provides a gating mechanism for enzyme activation. The rate constants defining these structural perturbations, from oxidized-->reduced and reduced-->oxidized states, have been determined by monitoring changes in both the natural emission from desulfoviridin and the emission from a surface-bound fluorophore (1,5-IAEDANS). Consistent results were obtained from these two independent experimental measurements (at 25 degrees C: kox-->red approximately 8 s-1, kred-->ox approximately 0.05 s-1). Activation energies for each transition have been determined from Arrhenius plots (ox-->red: delta G* 16.5 kcal mol-1, delta H* 3.5 kcal mol-1, delta S* -43.8 cal K-1 mol-1; red-->ox: delta G* 19.2 kcal mol-1, delta H* 11.3 kcal mol-1, delta S* -26.6 cal K-1 mol-1). These data are used to further develop a functional model previously proposed for this class of enzyme [Lui, S. M., Soriano, A., & Cowan, J. A. (1993) J. Am. Chem. Soc. 115, 10483; Lui, S. M., Liang, W., Soriano, A., & Cowan, J. A. (1994) J. Am. Chem. Soc. 116, 4531].(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Phylogeography of sulfate-reducing bacteria among disturbed sediments, disclosed by analysis of the dissimilatory sulfite reductase genes (dsrAB).

    PubMed

    Pérez-Jiménez, J R; Kerkhof, L J

    2005-02-01

    Sediment samples were collected worldwide from 16 locations on four continents (in New York, California, New Jersey, Virginia, Puerto Rico, Venezuela, Italy, Latvia, and South Korea) to assess the extent of the diversity and the distribution patterns of sulfate-reducing bacteria (SRB) in contaminated sediments. The SRB communities were examined by terminal restriction fragment (TRF) length polymorphism (TRFLP) analysis of the dissimilatory sulfite reductase genes (dsrAB) with NdeII digests. The fingerprints of dsrAB genes contained a total of 369 fluorescent TRFs, of which <20% were present in the GenBank database. The global sulfidogenic communities appeared to be significantly different among the anthropogenically impacted (petroleum-contaminated) sites, but nearly all were less diverse than pristine habitats, such as mangroves. A global SRB indicator species of petroleum pollution was not identified. However, several dsrAB gene sequences corresponding to hydrocarbon-degrading isolates or consortium members were detected in geographically widely separated polluted sites. Finally, a cluster analysis of the TRFLP fingerprints indicated that many SRB microbial communities were most similar on the basis of close geographic proximity (tens of kilometers). Yet, on larger scales (hundreds to thousands of kilometers) SRB communities could cluster with geographically widely separated sites and not necessarily with the site with the closest proximity. These data demonstrate that SRB populations do not adhere to a biogeographic distribution pattern similar to that of larger eukaryotic organisms, with the greatest species diversity radiating from the Indo-Pacific region. Rather, a patchy SRB distribution is encountered, implying an initially uniform SRB community that has differentiated over time. PMID:15691959

  10. Phylogeography of Sulfate-Reducing Bacteria among Disturbed Sediments, Disclosed by Analysis of the Dissimilatory Sulfite Reductase Genes (dsrAB)

    PubMed Central

    Pérez-Jiménez, J. R.; Kerkhof, L. J.

    2005-01-01

    Sediment samples were collected worldwide from 16 locations on four continents (in New York, California, New Jersey, Virginia, Puerto Rico, Venezuela, Italy, Latvia, and South Korea) to assess the extent of the diversity and the distribution patterns of sulfate-reducing bacteria (SRB) in contaminated sediments. The SRB communities were examined by terminal restriction fragment (TRF) length polymorphism (TRFLP) analysis of the dissimilatory sulfite reductase genes (dsrAB) with NdeII digests. The fingerprints of dsrAB genes contained a total of 369 fluorescent TRFs, of which <20% were present in the GenBank database. The global sulfidogenic communities appeared to be significantly different among the anthropogenically impacted (petroleum-contaminated) sites, but nearly all were less diverse than pristine habitats, such as mangroves. A global SRB indicator species of petroleum pollution was not identified. However, several dsrAB gene sequences corresponding to hydrocarbon-degrading isolates or consortium members were detected in geographically widely separated polluted sites. Finally, a cluster analysis of the TRFLP fingerprints indicated that many SRB microbial communities were most similar on the basis of close geographic proximity (tens of kilometers). Yet, on larger scales (hundreds to thousands of kilometers) SRB communities could cluster with geographically widely separated sites and not necessarily with the site with the closest proximity. These data demonstrate that SRB populations do not adhere to a biogeographic distribution pattern similar to that of larger eukaryotic organisms, with the greatest species diversity radiating from the Indo-Pacific region. Rather, a patchy SRB distribution is encountered, implying an initially uniform SRB community that has differentiated over time. PMID:15691959

  11. Inhibition of acid production in coal refuse amended with CaSO{sub 3}-based flue gas desulfurization by-products

    SciTech Connect

    Hao, Y.; Dick, W.A.; Beeghly, J.

    1998-12-31

    Oxidation of pyrite in coal refuse produces acid which caused environmental degradation. Some flue gas desulfurization (FGD) by-products contain calcium sulfite (CaSO{sub 3}) which is a strong reductant. Calcium sulfite competes with pyrite for oxygen resulting in inhibition of pyrite oxidation. In addition fly ash, CaCO{sub 3} and CaSO{sub 3} in FGD can neutralize acidity. Coal refuse, amended with FGD or its components, was packed into columns (2.5 x 13 cm) and leached weekly with water for 13 weeks. The pH, titratable acidity, and concentrations of Al, As, B, Ca, Fe, Pb, S, Se, were determined. The FGD containing CaSO{sub 2} inhibited acid production in coal refuse. The final leachate for FGD treatment had a pH of 5.3 and 20 mM of acidity (hydrogen ion) as compared to a pH of 1.7 and acidity of 480 mM for the control. Compared to the control, the FGD treatment yielded loser concentrations of all elements except for B and Ca. There was an interaction between all the components in the FGD and an indication that alterations of the ratio of components in FGD may significantly improve their inhibitory effect on acid production in coal refuse.

  12. Recovery of anhydrous Na{sub 2}SO{sub 4} from SO{sub 2}-scrubbing liquor by extractive crystallization: Liquid-liquid equilibria for aqueous solutions of sodium carbonate, sulfate, and/or sulfite plus acetone, 2-propanol, or tert-butyl alcohol

    SciTech Connect

    Lynn, S.; Cos, R.; Prausnitz, J.M. |; Schiozer, A.L.; Jaecksch, W.L.

    1996-11-01

    Sodium carbonate is a superior scrubbing agent for removing SO{sub 2} from combustion gases, but the resulting sodium sulfate (or sulfite) must be recovered for environmental reasons. Recovery by evaporative crystallization is energy-intensive; extractive crystallization provides an attractive alterative when technically feasible. Liquid/liquid equilibrium data were determined for two-phase mixtures containing aqueous solutions of sodium carbonate, sulfate, or sulfite and a polar organic solvent: acetone, 2-propanol, and 2-methylpropan-1-ol (i.e., tert-butyl alcohol). In the salt-saturated two-phase region, data were obtained between the lower consolute temperature and 60 C (50 C for acetone). data were also obtained at 35 C for liquid/liquid systems that were subsaturated with their respective salts and for liquid/liquid systems with overall molar ratios of sodium sulfite/sodium sulfate fixed at 25/75, 50/50, and 75/25. In the latter systems, it was found that the sulfite/sulfate ratios in the organic and aqueous phases were the same, i.e., there is no selectivity by these solvents for one salt relative to the other. The data show that any one of these solvents can be used to extract water from a concentrated solution of either sodium sulfite or sodium sulfate in a countercurrent extractor at 35 C, causing the anhydrous salt to crystallize. The wet solvent can be dried for recycle in a similar countercurrent operation at 35 C, using a saturated solution of Na{sub 2}CO{sub 3} as the drying agent. The number of moles of carbonate required for drying does not exceed the number of moles of sulfite-plus-sulfate precipitated. The process energy is about 0% of that required for single-stage evaporative crystallization of the same liquor.

  13. Processes to remove acid forming gases from exhaust gases

    DOEpatents

    Chang, Shih-Ger

    1994-01-01

    The present invention relates to a process for reducing the concentration of NO in a gas, which process comprises: (A) contacting a gas sample containing NO with a gaseous oxidizing agent to oxidize the NO to NO.sub.2 ; (B) contacting the gas sample of step (A) comprising NO.sub.2 with an aqueous reagent of bisulfite/sulfite and a compound selected from urea, sulfamic acid, hydrazinium ion, hydrazoic acid, nitroaniline, sulfanilamide, sulfanilic acid, mercaptopropanoic acid, mercaptosuccinic acid, cysteine or combinations thereof at between about 0.degree. and 100.degree. C. at a pH of between about 1 and 7 for between about 0.01 and 60 sec; and (C) optionally contacting the reaction product of step (A) with conventional chemical reagents to reduce the concentrations of the organic products of the reaction in step (B) to environ-mentally acceptable levels. Urea or sulfamic acid are preferred, especially sulfamic acid, and step (C) is not necessary or performed.

  14. The genome of Variovorax paradoxus strain TBEA6 provides new understandings for the catabolism of 3,3'-thiodipropionic acid and hence the production of polythioesters.

    PubMed

    Wübbeler, Jan Hendrik; Hiessl, Sebastian; Meinert, Christina; Poehlein, Anja; Schuldes, Jörg; Daniel, Rolf; Steinbüchel, Alexander

    2015-09-10

    The betaproteobacterium Variovorax paradoxus strain TBEA6 is capable of using 3,3'-thiodipropionic acid (TDP) as sole carbon and energy source for growth. This thioether is employed for several industrial applications. It can be applied as precursor for the biotechnical production of polythioesters (PTE), which represent persistent bioplastics. Consequently, the genome of V. paradoxus strain TBEA6 was sequenced. The draft genome sequence comprises approximately 7.2Mbp and 6852 predicted open reading frames. Furthermore, transposon mutagenesis to unravel the catabolism of TDP in strain TBEA6 was performed. Screening of 20,000 mutants mapped the insertions of Tn5::mob in 32 mutants, which all showed no growth with TDP as sole carbon source. Based on the annotated genome sequence together with transposon-induced mutagenesis, defined gene deletions, in silico analyses and comparative genomics, a comprehensive pathway for the catabolism of TDP is proposed: TDP is imported via the tripartite tricarboxcylate transport system and/or the TRAP-type dicarboxylate transport system. The initial cleavage of TDP into 3-hydroxypropionic acid (3HP) and 3-mercaptopropionic acid (3MP), which serves as precursor substrate for PTE synthesis, is most probably performed by the FAD-dependent oxidoreductase Fox. 3HP is presumably catabolized via malonate semialdehyde, whereas 3MP is oxygenated by the 3MP-dioxygenase Mdo yielding 3-sulfinopropionic acid (3SP). Afterwards, 3SP is linked to coenzyme A. The next step is the abstraction of sulfite by a desulfinase, and the resulting propionyl-CoA enters the central metabolism. Sulfite is oxidized to sulfate by the sulfite-oxidizing enzyme SoeABC and is subsequently excreted by the cells by the sulfate exporter Pse. PMID:26073999

  15. Nuclear Magnetic Resonance Identification of New Sulfonic Acid Metabolites of Chloroacetanilide Herbicides

    USGS Publications Warehouse

    Morton, M.D.; Walters, F.H.; Aga, D.S.; Thurman, E.M.; Larive, C.K.

    1997-01-01

    The detection of the sulfonic acid metabolites of the chloroacetanilide herbicides acetochlor, alachlor, butachlor, propachlor, and, more recently, metolachlor in surface and ground water suggests that a common mechanism for dechlorination exists via the glutathione conjugation pathway. The identification of these herbicides and their metabolites is important due to growing public awareness and concern about pesticide levels in drinking water. Although these herbicides are regulated, little is known about the fate of their metabolites in soil. The sulfonic acid metabolites were synthesized by reaction of the parent compounds with an excess of sodium sulfite. Acetochlor, alachlor, butachlor, metolachlor, and propachlor and their sulfonic acid metabolites were studied by nuclear magnetic resonance spectroscopy and fast atom bombardment mass spectrometry. This paper provides a direct method for the preparation and characterization of these compounds that will be useful in the analysis and study of chloracetanilide herbicides and their metabolites.

  16. Effect of ethylenediaminetetraacetic acid on the photocatalytic activities and flat-band potentials of cadmium sulfide and cadmium selenide

    SciTech Connect

    Uchihara, Toshio ); Matsumura, Michio; Ono, Junichi; Tsubomura, Hiroshi )

    1990-01-11

    Photocatalyzed hydrogen evolution on Pt-loaded CdS powder from aqueous solutions of sodium sulfite is enhanced by addition of a small amount of ethylenediaminetetraacetic acid (EDTA) to the solution. EDTA is hardly consumed by the reaction. It has been concluded from the measurements of the flat-band potential of CdS electrodes that EDTA and other chelating agents, such as 1,2-cyclohexanediaminetetraacetic acid and nitrilotriacetic acid, are adsorbed strongly on the surface of CdS and shift the conduction band energy toward the negative. The enhancement of the photocatalytic hydrogen evolution by the addition of EDTA is explained as being caused by the upward shift of the conduction band energy of CdS due to the negative charge of the chelating agents. The change of the conduction band energy by the adsorption of EDTA is observed also for CdSe electrodes. Although Pt-loaded CdSe powder is inactive for the hydrogen evolution from aqueous solutions of sodium sulfite, it generates hydrogen when EDTA is added to the solution.

  17. Molecular Modeling of Ammonium, Calcium, Sulfur, and Sodium Lignosulphonates in Acid and Basic Aqueous Environments

    NASA Astrophysics Data System (ADS)

    Salazar Valencia, P. J.; Bolívar Marinez, L. E.; Pérez Merchancano, S. T.

    2015-12-01

    Lignosulphonates (LS), also known as lignin sulfonates or sulfite lignin, are lignins in sulfonated forms, obtained from the "sulfite liquors," a residue of the wood pulp extraction process. Their main utility lies in its wide range of properties, they can be used as additives, dispersants, binders, fluxing, binder agents, etc. in fields ranging from food to fertilizer manufacture and even as agents in the preparation of ion exchange membranes. Since they can be manufactured relatively easy and quickly, and that its molecular size can be manipulated to obtain fragments of very low molecular weight, they are used as transport agents in the food industry, cosmetics, pharmaceutical and drug development, and as molecular elements for the treatment of health problems. In this paper, we study the electronic structural and optical characteristics of LS incorporating ammonium, sulfur, calcium, and sodium ions in acidic and basic aqueous media in order to gain a better understanding of their behavior and the very interesting properties exhibit. The studies were performed using the molecular modeling program HyperChem 5 using the semiempirical method PM3 of the NDO Family (neglect of differential overlap), to calculate the structural properties. We calculated the electronic and optical properties using the semiempirical method ZINDO / CI.

  18. A denuder technique for the measurement of nitrous acid in urban atmospheres

    NASA Astrophysics Data System (ADS)

    Febo, A.; Perrino, C.; Cortiello, M.

    A new denuder set-up for the measurement of nitrous acid in polluted atmospheres is described here. The set-up is composed of one tetrachloromercurate-coated denuder for the removal of SO 2 and two downstream sodium carbonate-coated denuders for the determination of nitrous acid by the differential technique [Febo et al., 19, 1517-1530 1990]. The removal of SO 2 is necessary in order to avoid the formation of artifact nitrite on the sulfite layer which results from the interaction between atmospheric SO 2 and the Na 2CO 3 coating. Because of this mechanism, the measurement of HONO by means of the previously used NaClNa 2CO 3Na 2CO 3 denuder set-up is heavily biased in all cases when SO 2 and NO 2 are present at high concentration levels (e.g. urban environments).

  19. Integration of the Mini-Sulfide Sulfite Anthraquinone (MSS-AQ) Pulping Process and Black Liquor Gasification in a Pulp Mill

    SciTech Connect

    Hasan Jameel, North Carolina State University; Adrianna Kirkman, North Carolina State University; Ravi Chandran,Thermochem Recovery International Brian Turk Research Triangle Institute; Brian Green, Research Triangle Institute

    2010-01-27

    As many of the recovery boilers and other pieces of large capital equipment of U.S. pulp mills are nearing the end of their useful life, the pulp and paper industry will soon need to make long-term investments in new technologies. The ability to install integrated, complete systems that are highly efficient will impact the industry’s energy use for decades to come. Developing a process for these new systems is key to the adoption of state-of-the-art technologies in the Forest Products industry. This project defined an integrated process model that combines mini-sulfide sulfite anthraquinone (MSS-AQ) pulping and black liquor gasification with a proprietary desulfurization process developed by the Research Triangle Institute. Black liquor gasification is an emerging technology that enables the use of MSS-AQ pulping, which results in higher yield, lower bleaching cost, lower sulfur emissions, and the elimination of causticization requirements. The recently developed gas cleanup/absorber technology can clean the product gas to a state suitable for use in a gas turbine and also regenerate the pulping chemicals needed to for the MSS-AQ pulping process. The combination of three advanced technologies into an integrated design will enable the pulping industry to achieve a new level of efficiency, environmental performance, and cost savings. Because the three technologies are complimentary, their adoption as a streamlined package will ensure their ability to deliver maximum energy and cost savings benefits. The process models developed by this project will enable the successful integration of new technologies into the next generation of chemical pulping mills. When compared to the Kraft reference pulp, the MSS-AQ procedures produced pulps with a 10-15 % yield benefit and the ISO brightness was 1.5-2 times greater. The pulp refined little easier and had a slightly lower apparent sheet density (In both the cases). At similar levels of tear index the MSS-AQ pulps also

  20. Lignor process for acidic rock drainage treatment.

    PubMed

    Zhuang, J M; Walsh, T

    2004-09-01

    The process using lignosulfonates for acidic rock drainage (ARD) treatment is referred to as the Lignor process. Lignosulfonates are waste by-products produced in the sulfite pulping process. The present study has shown lignosulfonates are able to protect lime from developing an external surface coating, and hence to favor its dissociation. Further, the addition of lignosulfonates to ARD solutions increased the dotting and settling rate of the formed sludge. The capability of lignosulfonates to form stable metal-lignin complexes makes them very useful in retaining metal ions and thus improving the long-term stability of the sludge against leaching. The Lignor process involves metal sorption with lignosulfonates, ARD neutralization by lime to about pH 7, pH adjustment with caustic soda to 9.4 - 9.6, air oxidation to lower the pH to a desired level, and addition of a minimum amount of FeCl3 for further removal of dissolved metals. The Lignor process removes all concerned metals (especially Al and Mn) from the ARD of the Britannia Mine (located at Britannia Beach, British Columbia, Canada) to a level lower than the limits of the B.C. Regulations. Compared with the high-density sludge (HDS) process, the Lignor process has many advantages, such as considerable savings in lime consumption, greatly reduced sludge volume, and improved sludge stability. PMID:15515269

  1. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain.

    PubMed

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

  2. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain

    PubMed Central

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

  3. [Microbiological research methods of drinking water regulation in West Germany from 1986. Suitability of the specifications of DIN 38411, Part 7, for the detection of sulfite-reducing, spore-forming anaerobes (Clostridia)].

    PubMed

    Schneider, J; Edenharder, R; Borneff, J

    1988-01-01

    The drinking-water regulations of the Federal Republic of Germany, from 22.05.1986, contains in paragraph 1 the instructions: "Drinking-water must be free of pathogens", and further in paragraph 11, "Responsibilities of the employer or other owner of a water supplying facility", include that: "The official authority may direct, that the employer...of a water supplying facility has to extend or has to cause to extend the microbiological examinations in order to determine, that...sulfite-reducing, spore-forming anaerobes (Clostridia) can not be detected in 20 ml of water..." The drinking-water regulations do not prescribe a bacteriological examination method in detail. Appendix 1 rules only that the examination for sulfite-reducing, spore-forming anaerobes (Clostridia) has to be performed after heating the sample to 75 degrees C (+/- 5 degrees C) for 10 min, by either the multiple-tube or membrane filtration method and cultivation in DRCM1-medium. If growth occurs, the presence of Clostridia must be confirmed by anaerobic and aerobic subcultivation. Furthermore, a DIN-instruction (DIN 38411, part 7) exists, which prescribes a detailed procedure for multiple-tube and membrane filtration methods, but does not provide for strict anaerobiosis. We were, however, unable to detect Clostridia in a multitude of water samples with the methods of the DIN-regulation. In order to examine if neglect of strict anaerobiosis was the reason for these failures, we checked the suitability of the DIN-regulation for the isolation of Clostridia from drinking water. In preliminary tests we examined up to four strains of the species C. botulinum, C. cadaveris, C. cochlearium, C. difficile, C. innocuum, C. perfringens and C. tertium for their ability to form heat-resistent spores in four sporulation media. It was, however, not possible to find a medium, in which all strains could sporulate within one week. In order to characterize the detection of these anaerobes in water, one particularly

  4. 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 ...

  5. 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 ...

  6. 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 ...

  7. The effects of nutrient limitation (nitrogen and phosphorus) on BOD removal from post-coagulated Pinus radiata sulfite pulp and paper mill wastewater in a baffled aerated stabilisation basin-laboratory pilot scale study.

    PubMed

    Dewi, R; Van Leeuwen, J A; Everson, A; Nothrop, S C; Chow, C W K

    2011-01-01

    The use of coagulation and flocculation for tertiary treatment of pulp and paper mill effluent was investigated, where the evaluation was based on the removal of nitrogen (N), phosphorus (P) and BOD from post-coagulated wastewater. The study was undertaken on laboratory scale aerobic stabilisation basins (ASB). Two post coagulated (alum) wastewaters were studied, where the BOD:N:P ratios were 100:1.3:0.06 and 100:1.3:0.3. These wastewaters were treated in two identical concurrent simulations (A & B). The influent ratio for 'A' was selected representing the composition of actual coagulated Pinus radiata sulfite pulp effluent mixed with paper mill effluent. The input composition for 'B' represented a typical P concentration found in existing pulp and paper mill effluents. Unmodified sludge collected from a mill-pond was added at 4% v/v to each simulation replicating the treatment conditions at full-scale. Similar high percentage removals of BOD and COD occurred after 28 days (two HRTs) which were 94 and 67% respectively for 'A', and 98 and 70% respectively for 'B', where both remained at steady state during the third HRT. A statistical analysis of the data revealed that there was no significant difference in the sample variance of the BOD and COD results.

  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. Role of sulfites and 4-hexylresorcinol in microbial growth and melanosis prevention of deepwater pink shrimp (Parapenaeus longirostris) using a controlled atmosphere.

    PubMed

    Martínez-Alvarez, O; Gómez-Guillén, M C; Montero, P

    2005-01-01

    A controlled atmosphere containing 48% CO2 and 7% O2 was used in association with refrigeration for storage of deepwater pink shrimp (Parapenaeus longirostris). Shrimp were treated with two different concentrations of sodium metabisulfite or 4-hexylresorcinol and subjected to the controlled atmosphere immediately after capture onboard ship or on arrival in port. Total volatile basic nitrogen, total viable counts, enterobacteria, lactic acid bacteria, and luminescent bacteria were determined, and black spot progression was evaluated. The combined effect of controlled atmosphere and melanosis inhibitors was used to delay black spot development as compared to the shrimp stored in ice alone. Storage under the controlled atmosphere without ice limited microbiological quality, namely, total viable counts, but enterobacterial growth was lower.

  11. Synthesis and performance evaluation of the new thickening agent of acidizing fluid

    NASA Astrophysics Data System (ADS)

    Tian, Zhenxing; Lv, Tong; Ren, Yanmei

    2010-07-01

    An acid thickener, poly (AMPS-co-DMC) was synthesized using water aqueous solution polymerization of these monomers such as 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and [2-(Methacryloyloxy) ethyl] trimethylammonium chloride (DMC), with ammonium persulfate and sodium sulfite redox system as initiator, while at 65°C, 25% of the total concentration of monomer, initiator dosage of 1.6% for the monomer mass and nitrogen protection condition. The paper discussed the property evaluation of poly(AMPS-co-DMC), it was shown that poly (AMPS-co-DMC) had good acid solubility (time for dissolving in acid is 21 min); acid containing 5.0% of poly(AMPSco-DMC) had a viscosity of greater than 25.0mPa•s the shearing stability and heat resistance of the system was good and over 90% at a shear rate of 170s-1; poly(AMPS-co-DMC) performed well in the presence of standard saline at a total concentration of 40000mg/L.

  12. Acid gas removal in a confined vortex scrubber

    SciTech Connect

    Hura, H.S.; Diehl, R.C.

    1994-12-31

    This paper reports results of acid gas removal tests performed on a confined vortex scrubber. The confined vortex scrubber (CVS) was developed at the Energy Technology Office of Textron Defense Systems (ETO/TDS) under company as well as Pittsburgh Energy Technology Center (PETC) funding. Previous tests on the CVS have demonstrated > 98% capture for sub-micron fly ash particles, as well as high mercury vapor removal from gas streams. In the recent tests water, sodium hydroxide, and sodium sulfite and bisulfite solutions were used to scrub out hydrochloric, acid gas (HCl) and sulfur dioxide (SO{sub 2}) doped in air supplied to the CVS. The capture efficiency was determined as a function of acid gas concentration, liquor flow rate, and liquor type. When the liquor was supplied only inside the CVS squirrel cage the HCl removal efficiency varied from 85--100% while the SO{sub 2} removal efficiency varied from 60--80%. Significantly higher captures were obtained at 1/3 rd the liquor flow rate by spraying the liquor upstream of the CVS in the air inlet pipe, and increasing the liquor/gas contact time. Total HCl captures > 95% and SO{sub 2} captures > 85% were obtained at a liquid/gas ratio of only 2 gal/1,000 acf for acid gas concentrations of 200--1,800 ppmv. There were no significant differences in the SO{sub 2}, scrubbing ability of the three sodium solutions, and the HCl scrubbing ability of water and a sodium hydroxide solution. These results suggest that the acid gas capture in the CVS is mass transfer limited because of the extremely short gas residence times in the CVS.

  13. Cloning and characterization of the gene coding for NADPH-sulfite reductase hemoprotein from Actinobacillus pleuropneumoniae and use of the protein product as a vaccine.

    PubMed

    Willson, P J; Gerlach, G F; Klashinsky, S; Potter, A A

    2001-10-01

    An expression library was constructed from an Actinobacillus pleuropneumoniae serotype 1 clinical isolate and screened with serum produced in pigs that had been vaccinated with the anionic fraction of a sodium chloride extract. One E. coli transformant was isolated that produced a large amount of a protein with an electrophoretic mobility of about 67,000 molecular mass. The A. pleuropneumoniae-derived DNA encoding the protein was localized and characterized by restriction enzyme digestion and nucleotide sequence analysis which showed strong homology with the cysI gene of E. coli. One open reading frame of 1764 bases in length was detected which encoded a cysI protein from serotype 1, with a calculated molecular mass of 66,678. The DNA encoding the protein was labeled with radio-isotope and the homologous gene was isolated from an A. pleuropneumoniae serotype 5a library. The serotype 5a gene was the same length, but the cysI protein from serotype 5a was slightly larger (66,849) due to 8 substitutions in the amino acid sequence. Expression plasmids containing cysI from either serotype of A. pleuropneumoniae complemented an E. coli cysI mutant. Pigs vaccinated with the recombinant cysI were protected from challenge with A. pleuropneumoniae of the homologous serotype.

  14. Mechanism of action of ethylene sulfite and vinylene carbonate electrolyte additives in LiNi1/3Mn1/3Co1/3O2/graphite pouch cells: electrochemical, GC-MS and XPS analysis.

    PubMed

    Madec, L; Petibon, R; Tasaki, K; Xia, J; Sun, J-P; Hill, I G; Dahn, J R

    2015-10-28

    The role of ethylene sulfite used either alone or in combination with VC in LiNi1/3Mn1/3Co1/3O2 (NMC)/graphite pouch cells was studied by correlating data from differential capacity (dQ/dV) analysis, gas chromatography/mass spectroscopy (GC-MS), theoretical calculations, ultrahigh precision coulometry, storage experiments and X-ray photoelectron spectroscopy. For cells containing VC alone, the electrochemical performance and gas production were greatly improved, compared to cells without VC, due to the formation of more stable and protective SEI films at both electrode surfaces by a polymer of VC. For cells with ES alone, a vigorous reactivity was observed due to preferential reduction that also generated large amounts of gas during formation. The dramatic decrease in electrochemical performance as well as the continuous production of gas during cycling in cells with ES was explained by the formation of a very thin and ineffective SEI film at the NMC surface. The suppression of the vigorous reaction of ES in cells with both ES and VC occurred because the solvation energy of Li(+) by VC is smaller than that of EC so VC is reduced first during formation. During charge-discharge cycling, a slow consumption of ES occurred and different sulfur species were observed on the electrodes when VC was combined with ES. SEI film formation processes and SEI composition were therefore dominated by VC and the electrochemical performance of cells with both VC and ES were similar compared to those of cells with VC alone.

  15. Analysis of Dissimilatory Sulfite Reductase and 16S rRNA Gene Fragments from Deep-Sea Hydrothermal Sites of the Suiyo Seamount, Izu-Bonin Arc, Western Pacific

    PubMed Central

    Nakagawa, Tatsunori; Ishibashi, Jun-Ichiro; Maruyama, Akihiko; Yamanaka, Toshiro; Morimoto, Yusuke; Kimura, Hiroyuki; Urabe, Tetsuro; Fukui, Manabu

    2004-01-01

    This study describes the occurrence of unique dissimilatory sulfite reductase (DSR) genes at a depth of 1,380 m from the deep-sea hydrothermal vent field at the Suiyo Seamount, Izu-Bonin Arc, Western Pacific, Japan. The DSR genes were obtained from microbes that grew in a catheter-type in situ growth chamber deployed for 3 days on a vent and from the effluent water of drilled holes at 5°C and natural vent fluids at 7°C. DSR clones SUIYOdsr-A and SUIYOdsr-B were not closely related to cultivated species or environmental clones. Moreover, samples of microbial communities were examined by PCR-denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA gene. The sequence analysis of 16S rRNA gene fragments obtained from the vent catheter after a 3-day incubation revealed the occurrence of bacterial DGGE bands affiliated with the Aquificae and γ- and ɛ-Proteobacteria as well as the occurrence of archaeal phylotypes affiliated with the Thermococcales and of a unique archaeon sequence that clustered with “Nanoarchaeota.” The DGGE bands obtained from drilled holes and natural vent fluids from 7 to 300°C were affiliated with the δ-Proteobacteria, genus Thiomicrospira, and Pelodictyon. The dominant DGGE bands retrieved from the effluent water of casing pipes at 3 and 4°C were closely related to phylotypes obtained from the Arctic Ocean. Our results suggest the presence of microorganisms corresponding to a unique DSR lineage not detected previously from other geothermal environments. PMID:14711668

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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 ...

  20. 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 ...

  1. Reclamation of acid, toxic coal spoils using wet flue gas desulfurization by-product, fly ash and sewage sludge. Final report

    SciTech Connect

    Kost, D.A.; Vimmerstedt, J.P.; Stehouwer, R.C.

    1997-03-01

    Establishment of vegetation on acid abandoned minelands requires modification of soil physical and chemical conditions. Covering the acid minesoil with topsoil or borrow soil is a common practice but this method may be restricted by availability of borrow soil and cause damage to the borrow site. An alternative approach is to use waste materials as soil amendments. There is a long history of using sewage sludge and fly ash as amendments for acid minesoils. Flue gas desulfurization (FGD) by-products are newer materials that are also promising amendments. Most flue gas sludges are mixtures of Calcium sulfate (CaSO{sub 4}), calcium sulfite (CaSO{sub 3}), calcium carbonate (CaCO{sub 3}), calcium hydroxide [Ca(OH){sub 2}], and fly ash. Some scrubbing processes produce almost pure gypsum (CaSO{sub 4}2H{sub 2}O). The primary purpose of the project is to evaluate two wet FGD by-products for effects on vegetation establishment and surface and ground water quality on an acid minesoil. One by-product from the Conesville, OH power plant (American Electric Power Service Corporation) contains primarily calcium sulfite and fly ash. The other by-product (Mg-gypsum FGD) from an experimental scrubber at the Zimmer power plant (Cincinnati Gas and Electric Company) is primarily gypsum with 4% magnesium hydroxide. These materials were compared with borrow soil and sewage sludge as minesoil amendments. Combinations of each FGD sludge with sewage sludge were also tested. This report summarizes two years of measurements of chemical composition of runoff water, ground water at two depths in the subsoil, soil chemical properties, elemental composition and yield of herbaceous ground cover, and elemental composition, survival and height of trees planted on plots treated with the various amendments. The borrow soil is the control for comparison with the other treatments.

  2. 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...

  3. 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 ...

  4. Sulfur K-Edge X-ray Absorption Spectroscopy and Density Functional Theory Calculations on Monooxo MoIV and Bisoxo MoVI Bis-dithiolenes: Insights into the Mechanism of Oxo Transfer in Sulfite Oxidase and Its Relation to the Mechanism of DMSO Reductase

    PubMed Central

    2015-01-01

    Sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations have been used to determine the electronic structures of two complexes [MoIVO(bdt)2]2– and [MoVIO2(bdt)2]2– (bdt = benzene-1,2-dithiolate(2−)) that relate to the reduced and oxidized forms of sulfite oxidase (SO). These are compared with those of previously studied dimethyl sulfoxide reductase (DMSOr) models. DFT calculations supported by the data are extended to evaluate the reaction coordinate for oxo transfer to a phosphite ester substrate. Three possible transition states are found with the one at lowest energy, stabilized by a P–S interaction, in good agreement with experimental kinetics data. Comparison of both oxo transfer reactions shows that in DMSOr, where the oxo is transferred from the substrate to the metal ion, the oxo transfer induces electron transfer, while in SO, where the oxo transfer is from the metal site to the substrate, the electron transfer initiates oxo transfer. This difference in reactivity is related to the difference in frontier molecular orbitals (FMO) of the metal–oxo and substrate–oxo bonds. Finally, these experimentally related calculations are extended to oxo transfer by sulfite oxidase. The presence of only one dithiolene at the enzyme active site selectively activates the equatorial oxo for transfer, and allows facile structural reorganization during turnover. PMID:24884723

  5. Continuous colorimetric screening assays for the detection of specific L- or D-α-amino acid transaminases in enzyme libraries.

    PubMed

    Heuson, Egon; Petit, Jean-Louis; Debard, Adrien; Job, Aurélie; Charmantray, Franck; de Berardinis, Véronique; Gefflaut, Thierry

    2016-01-01

    In the course of a project devoted to the stereoselective synthesis of non-proteinogenic α-amino acids using α-transaminases (α-TA), we report the design and optimization of generic high-throughput continuous assays for the screening of α-TA libraries. These assays are based on the use of L- or D-cysteine sulfinic acid (CSA) as irreversible amino donor and subsequent sulfite titration by colorimetry. The assays' quality was assessed under screening conditions. Hit selection thresholds were accurately determined for every couple of substrates and a library of 232 putative transaminases expressed in Escherichia coli host cells was screened. The reported high throughput screening assays proved very sensitive allowing the detection with high confidence of activities as low as 10 μU (i.e., 0.01 nmol substrate converted per min). The assays were also evidenced to be stereochemically discriminant since L-CSA and D-CSA allowed the exclusive detection of L-TA and D-TA, respectively. These generic assays thus allow testing the stereoselective conversion of a wide range of α-keto acids into α-amino acids of interest. As a proof of principle, the use of 2-oxo-4-phenylbutyric acid as acceptor substrate led to the identification of 54 new α-TA offering an access to valuable L- or D-homophenylalanine. PMID:26452497

  6. Continuous colorimetric screening assays for the detection of specific L- or D-α-amino acid transaminases in enzyme libraries.

    PubMed

    Heuson, Egon; Petit, Jean-Louis; Debard, Adrien; Job, Aurélie; Charmantray, Franck; de Berardinis, Véronique; Gefflaut, Thierry

    2016-01-01

    In the course of a project devoted to the stereoselective synthesis of non-proteinogenic α-amino acids using α-transaminases (α-TA), we report the design and optimization of generic high-throughput continuous assays for the screening of α-TA libraries. These assays are based on the use of L- or D-cysteine sulfinic acid (CSA) as irreversible amino donor and subsequent sulfite titration by colorimetry. The assays' quality was assessed under screening conditions. Hit selection thresholds were accurately determined for every couple of substrates and a library of 232 putative transaminases expressed in Escherichia coli host cells was screened. The reported high throughput screening assays proved very sensitive allowing the detection with high confidence of activities as low as 10 μU (i.e., 0.01 nmol substrate converted per min). The assays were also evidenced to be stereochemically discriminant since L-CSA and D-CSA allowed the exclusive detection of L-TA and D-TA, respectively. These generic assays thus allow testing the stereoselective conversion of a wide range of α-keto acids into α-amino acids of interest. As a proof of principle, the use of 2-oxo-4-phenylbutyric acid as acceptor substrate led to the identification of 54 new α-TA offering an access to valuable L- or D-homophenylalanine.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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)

  14. 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

  15. Inhibition of enzymatic browning of chlorogenic acid by sulfur-containing compounds.

    PubMed

    Kuijpers, Tomas F M; Narváez-Cuenca, Carlos-Eduardo; Vincken, Jean-Paul; Verloop, Annewieke J W; van Berkel, Willem J H; Gruppen, Harry

    2012-04-01

    The antibrowning activity of sodium hydrogen sulfite (NaHSO(3)) was compared to that of other sulfur-containing compounds. Inhibition of enzymatic browning was investigated using a model browning system consisting of mushroom tyrosinase and chlorogenic acid (5-CQA). Development of brown color (spectral analysis), oxygen consumption, and reaction product formation (RP-UHPLC-PDA-MS) were monitored in time. It was found that the compounds showing antibrowning activity either prevented browning by forming colorless addition products with o-quinones of 5-CQA (NaHSO(3), cysteine, and glutathione) or inhibiting the enzymatic activity of tyrosinase (NaHSO(3) and dithiothreitol). NaHSO(3) was different from the other sulfur-containing compounds investigated, because it showed a dual inhibitory effect on browning. Initial browning was prevented by trapping the o-quinones formed in colorless addition products (sulfochlorogenic acid), while at the same time, tyrosinase activity was inhibited in a time-dependent way, as shown by pre-incubation experiments of tyrosinase with NaHSO(3). Furthermore, it was demonstrated that sulfochlorogenic and cysteinylchlorogenic acids were not inhibitors of mushroom tyrosinase.

  16. 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)

  17. 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 ...

  18. 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 ...

  19. 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)

  20. 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.).

  1. Impacts of dyebath auxiliaries on the reductive discoloration of Acid Orange 7 dye by high-carbon iron filings.

    PubMed

    Kumar, Raja; Sinha, Alok

    2016-01-01

    This study proposed that the physicochemical effects of common dyebath auxiliaries on the bulk dye solution as well as on the iron surface can influence the reductive discoloration of effluent containing Acid Orange 7 (AO7) dye using high-carbon iron filings. Sodium chloride increased the discoloration rate because of the pitting corrosion on the iron surface, triggered by chloride anion. 'Salting out' effect of ammonium sulfate improved the reaction rate up to a certain concentration, beyond which it could compete with dye molecules for the reactive sites, as revealed by formed sulfite and sulfide. Urea drastically reduced the discoloration rates by its chaotropic effect on the bulk solution and by wrapping around the iron surface. Organic acids, namely acetic acid and citric acid, stimulated iron corrosion to improve the discoloration rates. The discoloration reaction was biphasic with an initial fast reaction phase, where in every case more than 70% discoloration was observed within 5 min of reaction, preceding a slow reaction phase. The experimental data could be well described using biphasic kinetics equation (R(2)> 0.997 in all cases) and a biphasic equation was developed considering the individual impact of co-existing auxiliaries on AO7 discoloration.

  2. Impacts of dyebath auxiliaries on the reductive discoloration of Acid Orange 7 dye by high-carbon iron filings.

    PubMed

    Kumar, Raja; Sinha, Alok

    2016-01-01

    This study proposed that the physicochemical effects of common dyebath auxiliaries on the bulk dye solution as well as on the iron surface can influence the reductive discoloration of effluent containing Acid Orange 7 (AO7) dye using high-carbon iron filings. Sodium chloride increased the discoloration rate because of the pitting corrosion on the iron surface, triggered by chloride anion. 'Salting out' effect of ammonium sulfate improved the reaction rate up to a certain concentration, beyond which it could compete with dye molecules for the reactive sites, as revealed by formed sulfite and sulfide. Urea drastically reduced the discoloration rates by its chaotropic effect on the bulk solution and by wrapping around the iron surface. Organic acids, namely acetic acid and citric acid, stimulated iron corrosion to improve the discoloration rates. The discoloration reaction was biphasic with an initial fast reaction phase, where in every case more than 70% discoloration was observed within 5 min of reaction, preceding a slow reaction phase. The experimental data could be well described using biphasic kinetics equation (R(2)> 0.997 in all cases) and a biphasic equation was developed considering the individual impact of co-existing auxiliaries on AO7 discoloration. PMID:27642841

  3. Photographic fixative poisoning

    MedlinePlus

    Photographic developer poisoning; Hydroquinone poisoning; Quinone poisoning; Sulfite poisoning ... Hydroquinones Quinones Sodium thiosulfate Sodium sulfite/bisulfite Boric acid Photographic fixative can also break down (decompose) to form sulfur dioxide gas.

  4. Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions.

    PubMed

    Guan, Ling; Shiiya, Ayaka; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2015-02-01

    Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions. PMID:25228086

  5. Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions.

    PubMed

    Guan, Ling; Shiiya, Ayaka; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2015-02-01

    Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions.

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. [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.

  17. Co-expression of bacterial aspartate kinase and adenylylsulfate reductase genes substantially increases sulfur amino acid levels in transgenic alfalfa (Medicago sativa L.).

    PubMed

    Tong, Zongyong; Xie, Can; Ma, Lei; Liu, Liping; Jin, Yongsheng; Dong, Jiangli; Wang, Tao

    2014-01-01

    Alfalfa (Medicago sativa L.) is one of the most important forage crops used to feed livestock, such as cattle and sheep, and the sulfur amino acid (SAA) content of alfalfa is used as an index of its nutritional value. Aspartate kinase (AK) catalyzes the phosphorylation of aspartate to Asp-phosphate, the first step in the aspartate family biosynthesis pathway, and adenylylsulfate reductase (APR) catalyzes the conversion of activated sulfate to sulfite, providing reduced sulfur for the synthesis of cysteine, methionine, and other essential metabolites and secondary compounds. To reduce the feedback inhibition of other metabolites, we cloned bacterial AK and APR genes, modified AK, and introduced them into alfalfa. Compared to the wild-type alfalfa, the content of cysteine increased by 30% and that of methionine increased substantially by 60%. In addition, a substantial increase in the abundance of essential amino acids (EAAs), such as aspartate and lysine, was found. The results also indicated a close connection between amino acid metabolism and the tricarboxylic acid (TCA) cycle. The total amino acid content and the forage biomass tested showed no significant changes in the transgenic plants. This approach provides a new method for increasing SAAs and allows for the development of new genetically modified crops with enhanced nutritional value. PMID:24520364

  18. 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.

  19. Metabolism of gambogic acid in rats: a rare intestinal metabolic pathway responsible for its final disposition.

    PubMed

    Yang, Jing; Ding, Li; Hu, Linlin; Qian, Wenjuan; Jin, Shaohong; Sun, Xiaoping; Wang, Zhenzhong; Xiao, Wei

    2011-04-01

    Gambogic acid (GA) is a promising natural anticancer candidate. Although the anticancer activity of GA has been well demonstrated, information regarding the metabolic fate of GA is limited. Previous studies suggested that GA is mainly excreted into intestinal tract in rats through bile after intravenous administration, whereas only traces appeared in the feces, suggesting that GA is metabolized extensively in the intestine. However, there has been no report about the intestinal metabolism of GA either in animals or humans. In this study, large amounts of two sulfonic acid metabolites of GA were found in the feces samples of rats after intravenous administration, and their structures were identified as 10-α sulfonic acid GA and 10-β sulfonic acid GA by comparison of the retention times and spectral data with those of synthesized reference substances using liquid chromatography-diode array detector-tandem mass spectrometry. This rare intestinal metabolic pathway mainly involves Michael addition of the sulfite ion to the 9,10 carbon-carbon double bond of α,β-unsaturated ketone. In addition, a more detailed metabolic profile in rats is proposed, according to the results of in vitro and in vivo studies. It was found that GA can be metabolized by a variety of routes, including monooxidation, hydration, glutathionylation, glucuronidation, and glucosidation in the liver of rats. These findings provide information on the major metabolic soft spot of GA in the intestine and liver of rats, which is not only useful in the future human metabolic study of this compound but also of value in the metabolic studies of GA analogs.

  20. 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 ...

  1. 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 ...

  2. Electrochemical and conversion electron mössbauer study of corrosion induced by acid rain

    NASA Astrophysics Data System (ADS)

    Vértes, Cs.; Lakatos-Varsányi, M.; Meisel, W.; Vértes, A.; Gütlich, P.

    1993-04-01

    The passivation of low carbon steel was studied in aqueous solution of 0.5M Na 2SO 4 +0.001M NaHSO 3 (pH 3.5, 6.5 and 8.5) which can be considered as a model of acid rain. The used conversion electron Mössbauer spectroscopy (CEMS) with the complementary electrochemical investigations proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6 5 while the measurements showed much weaker pitting at pH 8.5. The compositions and thicknesses of the passive films formed during the electrochemical treatments are determined from the CEM spectra. Only γ-FeOOH was found on the surface of the samples at pH 6.5 and 8.5. Nevertheless, at pH 3.5 the sextet belonging to Fe 3C appears in the spectra, and also FeS0 4H 2O could be detected in low concentration.

  3. Macroscopic to microscopic studies of flue gas desulfurization byproducts for acid mine drainage mitigation

    SciTech Connect

    Robbins, E.I.; Kalyoncu, R.S.; Finkelman, R.B.; Matos, G.R.; Barsotti, A.F.; Haefner, R.J.; Rowe, G.L. Jr.; Savela, C.E.; Eddy, J.I.

    1996-12-31

    The use of flue gas desulfurization (FGD) systems to reduce SO{sub 2} emissions has resulted in the generation of large quantities of byproducts. These and other byproducts are being stockpiled at the very time that alkaline materials having high neutralization potential are needed to mitigate acid mine drainage (AMD). FGD byproducts are highly alkaline materials composed primarily of unreacted sorbents (lime or limestone and sulfates and sulfites of Ca). The American Coal Ash Association estimated that approximately 20 million tons of FGD material were generated by electric power utilities equipped with wet lime-limestone PGD systems in 1993. Less than 5% of this material has been put to beneficial use for agricultural soil amendments and for the production of wallboard and cement. Four USGS projects are examining FGD byproduct use to address these concerns. These projects involve (1) calculating the volume of flue gas desulfurization (FGD) byproduct generation and their geographic locations in relation to AMD, (2) determining byproduct chemistry and mineralogy, (3) evaluating hydrology and geochemistry of atmospheric fluidized bed combustion byproduct as soil amendment in Ohio, and (4) analyzing microbial degradation of gypsum in anoxic limestone drains in West Virginia.

  4. 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…

  5. Exploration of Sulfur Assimilation of Aspergillus fumigatus Reveals Biosynthesis of Sulfur-Containing Amino Acids as a Virulence Determinant

    PubMed Central

    Dümig, Michaela; O'Keeffe, Gráinne; Binder, Jasmin; Doyle, Sean; Beilhack, Andreas

    2016-01-01

    Fungal infections are of major relevance due to the increased numbers of immunocompromised patients, frequently delayed diagnosis, and limited therapeutics. To date, the growth and nutritional requirements of fungi during infection, which are relevant for invasion of the host, are poorly understood. This is particularly true for invasive pulmonary aspergillosis, as so far, sources of (macro)elements that are exploited during infection have been identified to only a limited extent. Here, we have investigated sulfur (S) utilization by the human-pathogenic mold Aspergillus fumigatus during invasive growth. Our data reveal that inorganic S compounds or taurine is unlikely to serve as an S source during invasive pulmonary aspergillosis since a sulfate transporter mutant strain and a sulfite reductase mutant strain are fully virulent. In contrast, the S-containing amino acid cysteine is limiting for fungal growth, as proven by the reduced virulence of a cysteine auxotroph. Moreover, phenotypic characterization of this strain further revealed the robustness of the subordinate glutathione redox system. Interestingly, we demonstrate that methionine synthase is essential for A. fumigatus virulence, defining the biosynthetic route of this proteinogenic amino acid as a potential antifungal target. In conclusion, we provide novel insights into the nutritional requirements of A. fumigatus during pathogenesis, a prerequisite to understanding and fighting infection. PMID:26787716

  6. Insights from the Metagenome of an Acid Salt Lake: The Role of Biology in an Extreme Depositional Environment

    PubMed Central

    Johnson, Sarah Stewart; Chevrette, Marc Gerard; Ehlmann, Bethany L.; Benison, Kathleen Counter

    2015-01-01

    The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars. PMID:25923206

  7. Insights from the metagenome of an acid salt lake: the role of biology in an extreme depositional environment.

    PubMed

    Johnson, Sarah Stewart; Chevrette, Marc Gerard; Ehlmann, Bethany L; Benison, Kathleen Counter

    2015-01-01

    The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars.

  8. 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.

  9. 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 ...

  10. 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, ...

  11. 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 ...

  12. 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 ...

  13. 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 ...

  14. 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 ...

  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. Desulfosporosinus acididurans sp. nov.: an acidophilic sulfate-reducing bacterium isolated from acidic sediments.

    PubMed

    Sánchez-Andrea, Irene; Stams, Alfons J M; Hedrich, Sabrina; Ňancucheo, Ivan; Johnson, D Barrie

    2015-01-01

    Three strains of sulfate-reducing bacteria (M1(T), D, and E) were isolated from acidic sediments (White river and Tinto river) and characterized phylogenetically and physiologically. All three strains were obligately anaerobic, mesophilic, spore-forming straight rods, stained Gram-negative and displayed variable motility during active growth. The pH range for growth was 3.8-7.0, with an optimum at pH 5.5. The temperature range for growth was 15-40 °C, with an optimum at 30 °C. Strains M1(T), D, and E used a wide range of electron donors and acceptors, with certain variability within the different strains. The nominated type strain (M1(T)) used ferric iron, nitrate, sulfate, elemental sulfur, and thiosulfate (but not arsenate, sulfite, or fumarate) as electron acceptors, and organic acids (formate, lactate, butyrate, fumarate, malate, and pyruvate), alcohols (glycerol, methanol, and ethanol), yeast extract, and sugars (xylose, glucose, and fructose) as electron donors. It also fermented some substrates such as pyruvate and formate. Strain M1(T) tolerated up to 50 mM ferrous iron and 10 mM aluminum, but was inhibited by 1 mM copper. On the basis of phenotypic, phylogenetic, and genetic characteristics, strains M1(T), D, and E represent a novel species within the genus Desulfosporosinus, for which the name Desulfosporosinus acididurans sp. nov. is proposed. The type strain is M1(T) (=DSM 27692(T) = JCM 19471(T)). Strain M1(T) was the first acidophilic SRB isolated, and it is the third described species of acidophilic SRB besides Desulfosporosinus acidiphilus and Thermodesulfobium narugense.

  17. Succinic acid production by Actinobacillus succinogenes from batch fermentation of mixed sugars.

    PubMed

    Almqvist, Henrik; Pateraki, Chrysanthi; Alexandri, Maria; Koutinas, Apostolis; Lidén, Gunnar

    2016-08-01

    Succinic acid production from the monosaccharides xylose, arabinose, glucose, mannose and galactose was studied using the bacterium Actinobacillus succinogenes. In Duran bottle cultures, containing 10 g/L of each of sugar, succinic acid was produced from all sugars except for galactose. The highest succinate yield, 0.56 g/g, was obtained with glucose, whereas the succinate yield was 0.42, 0.38 and 0.44 g/g for xylose, mannose and arabinose, respectively. The specific succinate productivity was 0.7 g/g h for glucose, but below 0.2 g/g h for the other sugars. Batch bioreactor fermentations were carried out using a sugar mixture of the five sugars giving a total concentration of 50 g/L, mimicking the distribution of sugars in spent sulfite liquor (SSL) from Eucalyptus which is rich in xylose. In this mixture, an almost complete conversion of all sugars (except galactose) was achieved resulting in a final succinate concentration of 21.8-26.8 g/L and a total yield of 0.59-0.68 g/g. There was evidence of co-consumption of glucose and xylose, whereas mannose was consumed after glucose. The main by-products were acetate 0.14-0.20 g/g and formate 0.08-0.13 g/g. NADH balance calculations suggested that NADH required for succinate production was not met solely from formate and acetate production, but other means of NADH production was necessary. Results from mixed sugar fermentations were verified using SSL as substrate resulting in a succinate yield of 0.60 g/g. In addition, it was found that CO2 sparging could replace carbonate supply in the form of MgCO3 without affecting the succinate yield. PMID:27255975

  18. Metabolic potential of fatty acid oxidation and anaerobic respiration by abundant members of Thaumarchaeota and Thermoplasmata in deep anoxic peat.

    PubMed

    Lin, Xueju; Handley, Kim M; Gilbert, Jack A; Kostka, Joel E

    2015-12-01

    To probe the metabolic potential of abundant Archaea in boreal peats, we reconstructed two near-complete archaeal genomes, affiliated with Thaumarchaeota group 1.1c (bin Fn1, 8% abundance), which was a genomically unrepresented group, and Thermoplasmata (bin Bg1, 26% abundance), from metagenomic data acquired from deep anoxic peat layers. Each of the near-complete genomes encodes the potential to degrade long-chain fatty acids (LCFA) via β-oxidation. Fn1 has the potential to oxidize LCFA either by syntrophic interaction with methanogens or by coupling oxidation with anaerobic respiration using fumarate as a terminal electron acceptor (TEA). Fn1 is the first Thaumarchaeota genome without an identifiable carbon fixation pathway, indicating that this mesophilic phylum encompasses more diverse metabolisms than previously thought. Furthermore, we report genetic evidence suggestive of sulfite and/or organosulfonate reduction by Thermoplasmata Bg1. In deep peat, inorganic TEAs are often depleted to extremely low levels, yet the anaerobic respiration predicted for two abundant archaeal members suggests organic electron acceptors such as fumarate and organosulfonate (enriched in humic substances) may be important for respiration and C mineralization in peatlands.

  19. Metabolic potential of fatty acid oxidation and anaerobic respiration by abundant members of Thaumarchaeota and Thermoplasmata in deep anoxic peat

    SciTech Connect

    Lin, Xueju; Handley, Kim M.; Gilbert, Jack A.; Kostka, Joel E.

    2015-05-22

    To probe the metabolic potential of abundant Archaea in boreal peats, we reconstructed two near-complete archaeal genomes, affiliated with Thaumarchaeota group 1.1c (bin Fn1, 8% abundance), which was a genomically unrepresented group, and Thermoplasmata (bin Bg1, 26% abundance), from metagenomic data acquired from deep anoxic peat layers. Each of the near-complete genomes encodes the potential to degrade long-chain fatty acids (LCFA) via β-oxidation. Fn1 has the potential to oxidize LCFA either by syntrophic interaction with methanogens or by coupling oxidation with anaerobic respiration using fumarate as a terminal electron acceptor (TEA). Fn1 is the first Thaumarchaeota genome without an identifiable carbon fixation pathway, indicating that this mesophilic phylum encompasses more diverse metabolisms than previously thought. Furthermore, we report genetic evidence suggestive of sulfite and/or organosulfonate reduction by Thermoplasmata Bg1. In deep peat, inorganic TEAs are often depleted to extremely low levels, yet the anaerobic respiration predicted for two abundant archaeal members suggests organic electron acceptors such as fumarate and organosulfonate (enriched in humic substances) may be important for respiration and C mineralization in peatlands.

  20. Structural and functional insights from the metagenome of an acidic hot spring microbial planktonic community in the Colombian Andes.

    PubMed

    Jiménez, Diego Javier; Andreote, Fernando Dini; Chaves, Diego; Montaña, José Salvador; Osorio-Forero, Cesar; Junca, Howard; Zambrano, María Mercedes; Baena, Sandra

    2012-01-01

    A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters above sea level) acidic hot spring El Coquito (EC). A classification of unassembled metagenomic reads using different databases showed a high proportion of Gammaproteobacteria and Alphaproteobacteria (in total read affiliation), and through taxonomic affiliation of 16S rRNA gene fragments we observed the presence of Proteobacteria, micro-algae chloroplast and Firmicutes. Reads mapped against the genomes Acidiphilium cryptum JF-5, Legionella pneumophila str. Corby and Acidithiobacillus caldus revealed the presence of transposase-like sequences, potentially involved in horizontal gene transfer. Functional annotation and hierarchical comparison with different datasets obtained by pyrosequencing in different ecosystems showed that the microbial community also contained extensive DNA repair systems, possibly to cope with ultraviolet radiation at such high altitudes. Analysis of genes involved in the nitrogen cycle indicated the presence of dissimilatory nitrate reduction to N2 (narGHI, nirS, norBCDQ and nosZ), associated with Proteobacteria-like sequences. Genes involved in the sulfur cycle (cysDN, cysNC and aprA) indicated adenylsulfate and sulfite production that were affiliated to several bacterial species. In summary, metagenomic sequence data provided insight regarding the structure and possible functions of this hot spring microbial community, describing some groups potentially involved in the nitrogen and sulfur cycling in this environment. PMID:23251687

  1. Revealing biogenic sulfuric acid corrosion in sludge digesters: detection of sulfur-oxidizing bacteria within full-scale digesters.

    PubMed

    Huber, B; Drewes, J E; Lin, K C; König, R; Müller, E

    2014-01-01

    Biogenic sulfuric acid corrosion (BSA) is a costly problem affecting both sewerage infrastructure and sludge handling facilities such as digesters. The aim of this study was to verify BSA in full-scale digesters by identifying the microorganisms involved in the concrete corrosion process, that is, sulfate-reducing (SRB) and sulfur-oxidizing bacteria (SOB). To investigate the SRB and SOB communities, digester sludge and biofilm samples were collected. SRB diversity within digester sludge was studied by applying polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the dsrB-gene (dissimilatory sulfite reductase beta subunit). To reveal SOB diversity, cultivation dependent and independent techniques were applied. The SRB diversity studies revealed different uncultured SRB, confirming SRB activity and H2S production. Comparable DGGE profiles were obtained from the different sludges, demonstrating the presence of similar SRB species. By cultivation, three pure SOB strains from the digester headspace were obtained including Acidithiobacillus thiooxidans, Thiomonas intermedia and Thiomonas perometabolis. These organisms were also detected with PCR-DGGE in addition to two new SOB: Thiobacillus thioparus and Paracoccus solventivorans. The SRB and SOB responsible for BSA were identified within five different digesters, demonstrating that BSA is a problem occurring not only in sewer systems but also in sludge digesters. In addition, the presence of different SOB species was successfully associated with the progression of microbial corrosion. PMID:25353947

  2. Revealing biogenic sulfuric acid corrosion in sludge digesters: detection of sulfur-oxidizing bacteria within full-scale digesters.

    PubMed

    Huber, B; Drewes, J E; Lin, K C; König, R; Müller, E

    2014-01-01

    Biogenic sulfuric acid corrosion (BSA) is a costly problem affecting both sewerage infrastructure and sludge handling facilities such as digesters. The aim of this study was to verify BSA in full-scale digesters by identifying the microorganisms involved in the concrete corrosion process, that is, sulfate-reducing (SRB) and sulfur-oxidizing bacteria (SOB). To investigate the SRB and SOB communities, digester sludge and biofilm samples were collected. SRB diversity within digester sludge was studied by applying polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the dsrB-gene (dissimilatory sulfite reductase beta subunit). To reveal SOB diversity, cultivation dependent and independent techniques were applied. The SRB diversity studies revealed different uncultured SRB, confirming SRB activity and H2S production. Comparable DGGE profiles were obtained from the different sludges, demonstrating the presence of similar SRB species. By cultivation, three pure SOB strains from the digester headspace were obtained including Acidithiobacillus thiooxidans, Thiomonas intermedia and Thiomonas perometabolis. These organisms were also detected with PCR-DGGE in addition to two new SOB: Thiobacillus thioparus and Paracoccus solventivorans. The SRB and SOB responsible for BSA were identified within five different digesters, demonstrating that BSA is a problem occurring not only in sewer systems but also in sludge digesters. In addition, the presence of different SOB species was successfully associated with the progression of microbial corrosion.

  3. Structural and Functional Insights from the Metagenome of an Acidic Hot Spring Microbial Planktonic Community in the Colombian Andes

    PubMed Central

    Jiménez, Diego Javier; Andreote, Fernando Dini; Chaves, Diego; Montaña, José Salvador; Osorio-Forero, Cesar; Junca, Howard; Zambrano, María Mercedes; Baena, Sandra

    2012-01-01

    A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters above sea level) acidic hot spring El Coquito (EC). A classification of unassembled metagenomic reads using different databases showed a high proportion of Gammaproteobacteria and Alphaproteobacteria (in total read affiliation), and through taxonomic affiliation of 16S rRNA gene fragments we observed the presence of Proteobacteria, micro-algae chloroplast and Firmicutes. Reads mapped against the genomes Acidiphilium cryptum JF-5, Legionella pneumophila str. Corby and Acidithiobacillus caldus revealed the presence of transposase-like sequences, potentially involved in horizontal gene transfer. Functional annotation and hierarchical comparison with different datasets obtained by pyrosequencing in different ecosystems showed that the microbial community also contained extensive DNA repair systems, possibly to cope with ultraviolet radiation at such high altitudes. Analysis of genes involved in the nitrogen cycle indicated the presence of dissimilatory nitrate reduction to N2 (narGHI, nirS, norBCDQ and nosZ), associated with Proteobacteria-like sequences. Genes involved in the sulfur cycle (cysDN, cysNC and aprA) indicated adenylsulfate and sulfite production that were affiliated to several bacterial species. In summary, metagenomic sequence data provided insight regarding the structure and possible functions of this hot spring microbial community, describing some groups potentially involved in the nitrogen and sulfur cycling in this environment. PMID:23251687

  4. Effects of natural water ions and humic acid on catalytic nitrate reduction kinetics using an alumina supported Pd-Cu catalyst.

    PubMed

    Chaplin, Brian P; Roundy, Eric; Guy, Kathryn A; Shapley, John R; Werth, Charles J

    2006-05-01

    Catalytic nitrate reduction was evaluated for the purpose of drinking water treatment. Common anions present in natural waters and humic acid were evaluated for their effects on NO3(-) hydrogenation over a bimetallic supported catalyst (Pd-Cu/gamma-Al2O3). Groundwater samples, with and without powder activated carbon (PAC) pretreatment, were also evaluated. In the absence of inhibitors the NO3- reduction rate was 2.4 x 10(-01) L/min g cat. However, the addition of constituents (SO4(2-), SO3(2-), HS-, CI-, HCO3-, OH-, and humic acid) on the order of representative concentrations for drinking water decreased the NO3- reduction rate. Sulfite, sulfide, and elevated chloride decreased the NO3- reduction rate by over 2 orders of magnitude. Preferential adsorption of Cl- inhibited NO3- reduction to a greater extent than NO2- reduction. Partial regeneration of catalysts exposed to SO3(2-) was achieved by using a dilute hypochlorite solution, however Cu dissolution occurred. Dissolved constituents in the groundwater sample decreased the NO3- reduction rate to 3.7 x 10(-03) L/min g cat and increased ammonia production. Removal of dissolved organic matter from the groundwater using PAC increased the NO3- reduction rate to 5.06 x 10(-02) L/min g cat and decreased ammonia production. Elemental analyses of catalysts exposed to the natural groundwater suggest that mineral precipitation may also contribute to catalyst fouling. PMID:16719114

  5. Desulfotomaculum geothermicum sp. nov., a thermophilic, fatty acid-degrading, sulfate-reducing bacterium isolated with H2 from geothermal ground water.

    PubMed

    Daumas, S; Cord-Ruwisch, R; Garcia, J L

    1988-01-01

    A strictly anaerobic, thermophilic, fatty acids-degrading, sporulating sulfate-reducing bacterium was isolated from geothermal ground water. The organism stained Gram-negative and formed gas vacuoles during sporulation. Lactate, ethanol, fructose and saturated fatty acids up to C18 served as electron donors and carbon sources with sulfate as external electron acceptor. Benzoate was not used. Stoichiometric measurements revealed a complete oxidation of part of butyrate although growth with acetate as only electron donor was not observed. The rest of butyrate was oxidized to acetate. The strain grew chemolithoautotrophically with hydrogen plus sulfate as energy source and carbon dioxide as carbon source without requirement of additional organic carbon like acetate. The strain contained a c-type cytochrome and presumably a sulfite reductase P582. Optimum temperature, pH and NaCl concentration for growth were 54 degrees C, pH 7.3-7.5 and 25 to 35 g NaCl/l. The G + C content of DNA was 50.4 mol %. Strain BSD is proposed as a new species of the spore-forming sulfate-reducing genus Desulfotomaculum, D. geothermicum.

  6. 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.

  7. 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.

  8. 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…

  9. 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.

  10. 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 ...

  11. 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 ...

  12. 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.

  13. 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 ...

  14. 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 ...

  15. 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 ...

  16. 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 , ...

  17. 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 ...

  18. 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 ...

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. 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…

  4. 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)…

  5. 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.…

  6. [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…

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. [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?

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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;…

  13. 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...

  14. 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 ...

  15. 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

  16. 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)

  17. 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 ...

  18. 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...

  19. 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. ...

  20. 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.