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Sample records for 5-hydroxymethylfurfural degradation pathways

  1. Degradation of 5-hydroxymethylfurfural during yeast fermentation.

    Science.gov (United States)

    Akıllıoglu, Halise Gül; Mogol, Burçe Ataç; Gökmen, Vural

    2011-12-01

    5-Hydroxymethyl furfural (HMF) may occur in malt in high quantities depending on roasting conditions. However, the HMF content of different types of beers is relatively low, indicating its potential for degradation during fermentation. This study investigates the degradation kinetics of HMF in wort during fermentation by Saccharomyces cerevisiae. The results indicated that HMF decreased exponentially as fermentation progressed. The first-order degradation rate of HMF was 0.693 × 10(-2) and 1.397 × 10(-2)min(-1) for wort and sweet wort, respectively, indicating that sugar enhances the activity of yeasts. In wort, HMF was converted into hydroxymethyl furfuryl alcohol by yeasts with a high yield (79-84% conversion). Glucose and fructose were utilised more rapidly by the yeasts in dark roasted malt than in pale malt (pyeast cells, and presence of sugars in the fermentation medium increases this activity. PMID:22010851

  2. 5-Hydroxymethylfurfural protects against ER stress-induced apoptosis in GalN/TNF-α-injured L02 hepatocytes through regulating the PERK-eIF2α signaling pathway.

    Science.gov (United States)

    Jiang, Ze-Qun; Ma, Yan-Xia; Li, Mu-Han; Zhan, Xiu-Qin; Zhang, Xu; Wang, Ming-Yan

    2015-12-01

    5-Hydroxymethylfurfural (5-HMF), a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the protective effect of 5-HMF in human L02 hepatocytes injured by D-galactosamine (GalN) and tumor necrosis factor-α (TNF-α) in vitro and to explore the underlying mechanisms of action. Our results showed that 5-HMF caused significant increase in the viability of L02 cells injured by GalN/TNF-α, in accordance with a dose-dependent decrease in apoptotic cell death confirmed by morphological and flow cytometric analyses. Based on immunofluorescence and Western blot assays, we found that GalN/TNF-α induced ER stress in the cells, as indicated by the disturbance of intracellular Ca(2+) concentration, the activation of protein kinase RNA (PKR)-like ER kinase (PERK), phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α), and expression of ATF4 and CHOP proteins, which was reversed by 5-HMF pre-treatment in a dose-dependent manner. The anti-apoptotic effect of 5-HMF was further evidenced by balancing the expression of Bcl-2 family members. In addition, the knockdown of PERK suppressed the expression of phospho-PERK, phospho-eIF2α, ATF4, and CHOP, resulting in a significant decrease in cell apoptosis after the treatment with GalN/TNF-α. 5-HMF could enhance the effects of PERK knockdown, protecting the cells against the GalN/TNF-α insult. In conclusion, these findings demonstrate that 5-HMF can effectively protect GalN/TNF-α-injured L02 hepatocytes against ER stress-induced apoptosis through the regulation of the PERK-eIF2α signaling pathway, suggesting that it is a possible candidate for liver disease therapy. PMID:26721708

  3. Dehydration of Different Ketoses and Aldoses to 5-Hydroxymethylfurfural

    NARCIS (Netherlands)

    van Putten, Robert-Jan; Soetedjo, Jenny N. M.; Pidko, Evgeny A.; van der Waal, Jan C.; Hensen, Emiel J. M.; de Jong, Ed; Heeres, Hero J.

    2013-01-01

    5-Hydroxymethylfurfural (HMF) is considered an important building block for future bio-based chemicals. Here, we present an experimental study using different ketoses (fructose, sorbose, tagatose) and aldoses (glucose, mannose, galactose) under aqueous acidic conditions (65gL(-1) substrate, 100-160

  4. 5-Hydroxymethylfurfural content in foodstuffs determined by micellar electrokinetic chromatography

    OpenAIRE

    Teixidó, Erika; Núñez Burcio, Oscar; Santos Vicente, Francisco Javier; Galcerán Huguet, M. Teresa

    2010-01-01

    Micellar electrokinetic chromatography (MEKC) has been applied for the determination of 5-hydroxymethylfurfural in several foodstuffs. A 75 mM phosphate buffer solution at pH 8.0 containing 100 mM sodium dodecylsulfate was used as background electrolyte (BGE), and the separation was performed by applying +25 kV in a 50 µm I.D. uncoated fused-silica capillary. Good linearity over the range 2.5-250 mg kg-1 (r2 ≥ 0.999) and run-to-run and day-to-day precisions at low and medium concentration lev...

  5. Synthesis of Bis(hydroxylmethylfurfuryl)amine Monomers from 5-Hydroxymethylfurfural.

    Science.gov (United States)

    Xu, Zhanwei; Yan, Peifang; Liu, Kairui; Wan, Lu; Xu, Wenjuan; Li, Huixiang; Liu, Xiumei; Zhang, Z Conrad

    2016-06-01

    We report the synthesis of bis(hydroxylmethylfurfuryl)amine (BHMFA) from 5-hydroxymethylfurfural (5-HMF) by reacting 5-HMF with primary amines in the presence of homogeneous Ru(II) catalysts having sterically strained ligands. BHMFA is a group of furan-based monomers that offer great potential to form functional biopolymers with tunable properties. A range of primary amines, such as aliphatic and benzyl amines, are readily converted with 5-HMF to form the corresponding BHMFA in good yields. The reaction proceeds through reductive amination of 5-HMF with primary amine to form secondary amine, followed by reductive amination of 5-HMF with in situ generated secondary amine to produce BHMFA. PMID:27151257

  6. Acrylamide and 5-hydroxymethylfurfural formation during baking of biscuits: Part I: Effects of sugar type.

    Science.gov (United States)

    Nguyen, Ha T; Van der Fels-Klerx, H J Ine; Peters, Ruud J B; Van Boekel, Martinus A J S

    2016-02-01

    This study aimed to investigate the effects of sugar type on the reaction mechanism for formation of acrylamide and 5-hydroxymethylfurfural (HMF) during the baking of biscuits at 200°C using multiresponse modelling. Four types of biscuits were prepared: (1) with sucrose, (2) with glucose and fructose, (3) with fructose only and (4) with glucose only. Experimental data showed that HMF concentration was highest in biscuits with glucose and fructose, whereas acrylamide concentration was highest in biscuits with glucose, also having the highest asparagine concentration. Proposed mechanistic models suggested that HMF is formed via caramelisation and that acrylamide formation follows the specific amino acid route, i.e., reducing sugars react with asparagine to form the Schiff base before decarboxylation, to generate acrylamide without the Amadori rearrangement product and sugar fragmentation. Study results contribute to understanding chemical reaction pathways in real food products.

  7. Acrylamide and 5-hydroxymethylfurfural formation during baking of biscuits: Part I: Effects of sugar type.

    Science.gov (United States)

    Nguyen, Ha T; Van der Fels-Klerx, H J Ine; Peters, Ruud J B; Van Boekel, Martinus A J S

    2016-02-01

    This study aimed to investigate the effects of sugar type on the reaction mechanism for formation of acrylamide and 5-hydroxymethylfurfural (HMF) during the baking of biscuits at 200°C using multiresponse modelling. Four types of biscuits were prepared: (1) with sucrose, (2) with glucose and fructose, (3) with fructose only and (4) with glucose only. Experimental data showed that HMF concentration was highest in biscuits with glucose and fructose, whereas acrylamide concentration was highest in biscuits with glucose, also having the highest asparagine concentration. Proposed mechanistic models suggested that HMF is formed via caramelisation and that acrylamide formation follows the specific amino acid route, i.e., reducing sugars react with asparagine to form the Schiff base before decarboxylation, to generate acrylamide without the Amadori rearrangement product and sugar fragmentation. Study results contribute to understanding chemical reaction pathways in real food products. PMID:26304386

  8. 5-Hydroxymethylfurfural content in foodstuffs determined by micellar electrokinetic chromatography.

    Science.gov (United States)

    Teixidó, Erika; Núñez, Oscar; Santos, F Javier; Galceran, M Teresa

    2011-06-15

    Micellar electrokinetic chromatography (MEKC) has been applied for the determination of 5-hydroxymethylfurfural in several foodstuffs. A 75mM phosphate buffer solution at pH 8.0 containing 100mM sodium dodecylsulphate was used as background electrolyte (BGE), and the separation was performed by applying +25kV in a 50μm I.D. uncoated fused-silica capillary. Good linearity over the range 2.5-250mgkg(-1) (r(2)⩾0.999) and run-to-run and day-to-day precisions at low and medium concentration levels were obtained. Sample limit of detection (0.7mgkg(-1)) and limit of quantification (2.5mgkg(-1)) were established by preparing the standards in blank matrix. The procedure was validated by comparing the results with those obtained with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Levels of HMF in 45 different foodstuffs such as breakfast cereals, toasts, honey, orange juice, apple juice, jam, coffee, chocolate and biscuits were determined. PMID:25213975

  9. Protein Engineering of GRE2 from Saccharomyces cerevisiae for Enhanced Detoxification of 5-hydroxymethylfurfural

    Science.gov (United States)

    Furfural and 5-hydroxymethylfurfural (HMF) are representative inhibitors generated by lignocellulosic biomass pretreatment such as dilute acid hydrolysis that inhibit microbial growth and subsequent fermentation. It is possible to in situ detoxify these inhibitory compounds using tolerant Saccharom...

  10. PRODUCTION OF 5-HYDROXYMETHYLFURFURAL (HMF) VIA FRUCTOSE DEHYDRATION: EFFECT OF SOLVENT AND SALTING-OUT

    OpenAIRE

    F. N. D. C. Gomes; L. R. Pereira; N. F. P. Ribeiro; M. M. V. M. Souza

    2015-01-01

    Abstract 5-Hydroxymethylfurfural (HMF) is a key renewable platform compound for production of fuels and chemical intermediates. The production of 5-hydroxymethylfurfural (HMF) from fructose dehydration was studied using H3PO4 as catalyst, in organic/water system with different solvents (acetone, 2-butanol and ethyl ether). The effect of fructose concentration, temperature and acid concentration was investigated in acetone/water medium. The increase in fructose concentration favors the formati...

  11. 5-Hydroxymethylfurfural from wine-processed Fructus corni inhibits hippocampal neuron apoptosis***

    Institute of Scientific and Technical Information of China (English)

    Hai Gu; Zequn Jiang; Mingyan Wang; Haiying Jiang; Fengming Zhao; Xia Ding; Baochang Cai; Zhen Zhan

    2013-01-01

    Previous studies have shown that 5-hydroxymethylfurfural, a compound extracted from wine- pro-cessed Fructus corni, has a protective effect on hippocampal neurons. The present study was de-signed to explore the related mechanisms. Our study revealed that high and medium doses (10, 1μmol/L) of 5-hydroxymethylfurfural could improve the morphology of H2O2-treated rat hippocampal neurons as revealed by inverted phase-contrast microscopy and transmission electron microscopy. MTT results showed that incubation with high and medium doses of 5-hydroxymethylfurfural caused a significant increase in the viability of neuronal cells injured by H2O2. Flow cytometry assays con-firmed that H2O2 could induce cellapoptosis, while high and medium doses of 5-hydroxymethylfurfural had a visible protective effect on apoptotic rat hippocampal neurons. Re-al-time PCR and western blot analysis showed that high and medium doses of 5-hydroxymethylfurfural prevented H2O2-induced up-regulation of p53, Bax and caspase-3 and antagonized the down-regulation of Bcl-2 induced by H2O2 treatment. These results suggested that 5-hydroxymethylfurfural could inhibit apoptosis of cultured rat hippocampal neurons injured by H2O2 via increase in Bcl-2 levels and decrease in p53, Bax and caspase-3 protein expression lev-els.

  12. [Effects of furfural and 5-hydroxymethylfurfural on succinic acid production by Escherichia coli].

    Science.gov (United States)

    Wang, Dan; Wang, Honghui; Wang, Jing; Wang, Nan; Zhang, Jie; Xing, Jianmin

    2013-10-01

    Succinic acid production by fermentation from biomass, especially the lignocellulosic hydrolysate, is an alternative to chemical synthesis. Many studies report the inhibition of cell growth and succinic acid production from lignocellulosic hydrolysate, hardly is known about the actual kinetic and mechanism of the inhibition of individual factors. In this study, we studied inhibition effects of furfurals and 5-hydroxymethylfurfural (5-HMF) on cell growth and succinic acid production of engineered E. coli. Cell growth and succinic acid titer were severely inhibited by furfural and HMF with both concentrations higher than 0.8 g/L. Cell growth was totally inhibited when the concentration of furfural was above 6.4 g/L, or the concentration of HMF was above 12.8 g/L. At the concentration of maximum toleration, which was 3.2 g/L, furfural decreased the cell mass by 77.8% and the succinic acid titer by 36.1%. HMF decreased the cell mass by 13.6% and the succinic acid titer by 18.3%. Activity measurements of key enzymes revealed that phosphoenolpyruvate carboxylase, malate dehydrogenase, fumarate reductase all were inhibited by furfural and HMF. This study gave a quantitative view to the succinic acid production under the inhibition of lignocellulose degradation products and will help overcome the difficulties of the lignocellulosic hydrolysate fermentation.

  13. One-pot conversion of disaccharide into 5-hydroxymethylfurfural catalyzed by imidazole ionic liquid.

    Science.gov (United States)

    Qu, Yongshui; Li, Li; Wei, Quanyuan; Huang, Chongpin; Oleskowicz-Popiel, Piotr; Xu, Jian

    2016-01-01

    Conversion of carbohydrate into 5-hydroxymethylfurfural (5- HMF), a versatile, key renewable platform compound is regarded as an important transformation in biomass-derived carbohydrate chemistry. A variety of ILs, not only acidic but also alkaline ILs, were synthesized and used as catalyst in the production of 5-HMF from disaccharide. Several factors including reaction temperature, IL dosage, solvent and reaction time,were found to influence the yield of 5-HMF from cellobiose. Of the ILs tested, hydroxy-functionalized ionic liquid (IL), 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate ([AEMIM]BF4) showed the highest catalytic activity and selectivity. 5-HMF yield of 68.71% from sucrose was obtained after 6 hrs at 160 °C. At the same condition with cellobiose as substrate, 5-HMF yield was 24.73%. In addition, 5-HMF also exhibited good stablity in this reaction system. Moreover, a kinetic analysis was carried out in both acidic and alkaline IL-catalyzed system, suggesting main side reaction in the conversion of fructose catalyzed by acidic and alkaline IL was polymerization of fructose and 5-HMF degradation, respectively. PMID:27181523

  14. Confirmation of patulin and 5-hydroxymethylfurfural in apple juice by gas chromatography/mass spectrometry.

    Science.gov (United States)

    Rupp, H S; Turnipseed, S B

    2000-01-01

    A gas chromatographic/mass spectrometric (GC/MS) method was developed for the confirmation of patulin and 5-hydroxymethylfurfural (HMF) extracted from apple juice. The extraction is based on the official AOAC method for liquid chromatographic analysis. Juice extracts are quickly and easily derivatized with bis(trimethylsilyl)trifluoracetamide under mild conditions, and the trimethylsilyl ethers of the analytes are stable for at least several hours. The analytes are determined by GC/MS using an electron-impact source and selected ion monitoring of characteristic ions. For both analytes, the interassay differences between base-peak ratios for samples and standards were all <7.1% (absolute). The presence of patulin was confirmed at fortification levels of about 30-400 microg/L and naturally occurring levels of about 80-400 microg/L. The presence of HMF was also confirmed at levels < or = 2 mg/L. The proposed mass spectral fragmentation pathways of the analytes are presented. PMID:10868584

  15. Synergy of boric acid and added salts in the catalytic dehydration of hexoses to 5-hydroxymethylfurfural in water

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Mielby, Jerrik Jørgen; Riisager, Anders

    2011-01-01

    Boric acid and salts showed a synergistic effect on the dehydration of concentrated aqueous sugar solutions to yield 5-hydroxymethylfurfural.......Boric acid and salts showed a synergistic effect on the dehydration of concentrated aqueous sugar solutions to yield 5-hydroxymethylfurfural....

  16. Acrylamide and 5-hydroxymethylfurfural formation during baking of biscuits: Part I: Effects of sugar type

    NARCIS (Netherlands)

    Nguyen, T.T.H.; Fels, van der H.J.; Peters, R.J.B.; Boekel, van T.

    2016-01-01

    This study aimed to investigate the effects of sugar type on the reaction mechanism for formation of acrylamide and 5-hydroxymethylfurfural (HMF) during the baking of biscuits at 200 °C using multiresponse modelling. Four types of biscuits were prepared: (1) with sucrose, (2) with glucose and fructo

  17. Caprolactam from Renewable Resources : Catalytic Conversion of 5-Hydroxymethylfurfural into Caprolactone

    NARCIS (Netherlands)

    Buntara, Teddy; Noel, Sebastien; Phua, Pim Huat; Melián-Cabrera, Ignacio; Vries, Johannes G. de; Heeres, Hero J.

    2011-01-01

    Renewable nylon: 5-Hydroxymethylfurfural (HMF), which can be obtained from renewable resources such as D-fructose, was converted into caprolactone with very good overall selectivity in only three steps. The new route involves two hydrogenation steps to obtain 1,6-hexanediol, which was oxidatively cy

  18. Efficient microwave-assisted synthesis of 5-hydroxymethylfurfural from concentrated aqueous fructose

    DEFF Research Database (Denmark)

    Søndergaard Hansen, Thomas; Woodley, John; Riisager, Anders

    2009-01-01

    Studies on the HCl-catalysed microwave-assisted dehydration of highly concentrated aqueous fructose (27 wt %) to 5-hydroxymethylfurfural (HMF) revealed a significant increase in the fructose conversion rate over the conventional heated systems. Water, being the most benign solvent and therefore...

  19. Gold-Catalyzed Aerobic Oxidation of 5-Hydroxymethylfurfural in Water at Ambient Temperature

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Woodley, John;

    2009-01-01

    The aerobic oxidation of 5-hydroxymethylfurfural, a versatile biomass-derived chemical, is examined in water with a titania-supported gold-nanoparticle catalyst at ambient temperature (30 degrees C). The selectivity of the reaction towords 2,5-furandicarboxylic acid and the intermediate oxidation...

  20. PRODUCTION OF 5-HYDROXYMETHYLFURFURAL (HMF VIA FRUCTOSE DEHYDRATION: EFFECT OF SOLVENT AND SALTING-OUT

    Directory of Open Access Journals (Sweden)

    F. N. D. C. Gomes

    2015-03-01

    Full Text Available Abstract 5-Hydroxymethylfurfural (HMF is a key renewable platform compound for production of fuels and chemical intermediates. The production of 5-hydroxymethylfurfural (HMF from fructose dehydration was studied using H3PO4 as catalyst, in organic/water system with different solvents (acetone, 2-butanol and ethyl ether. The effect of fructose concentration, temperature and acid concentration was investigated in acetone/water medium. The increase in fructose concentration favors the formation of condensation products and rehydration products are favored at high acid concentration. The solvents exhibited similar performance when the volume ratio of organic to aqueous phase was 1:1, but when this ratio increases to 2:1, the HMF yield obtained with ether was much lower. NaCl addition to the aqueous phase promoted the extraction of HMF to the organic phase, with an HMF yield of 80% in the case of 2:1 acetone/water medium.

  1. Acrylamide and 5-hydroxymethylfurfural formation in reconstituted potato chips during frying

    OpenAIRE

    Miao, YuTian; Zhang, HuanJie; Zhang, LuLu; Wu, SiJia; Sun, Yijia; Shan, Yu; Yuan, Yuan

    2013-01-01

    In our present paper, the effect of water activity and processing conditions in reconstituted potato chips was considered as a model to investigate the changes of acrylamide (AA) and 5-hydroxymethylfurfural (HMF). The results suggested that the formation of AA and HMF was highly correlated with frying temperature and time. Water activity could also influence the formation of AA and HMF. Meanwhile, the formation of HMF has significant correlation with the formation of AA in reconstituted potat...

  2. Multiple gene mediated aldehyde reduction is a mechanism of in situ detoxification of furfural and 5-hydroxymethylfurfural by Saccharomyces cerevisiae

    Science.gov (United States)

    Furfural and HMF (5-hydroxymethylfurfural) are representative inhibitors to ethanologenic yeast generated from biomass pretreatment using dilute acid hydrolysis. Few yeast strains tolerant to inhibitors are available. We have developed tolerant strains of Saccharomyces cerevisiae with enhanced bio...

  3. Effect of Storage on Acrylamide and 5-hydroxymethylfurfural Contents in Selected Processed Plant Products with Long Shelf-life.

    Science.gov (United States)

    Michalak, Joanna; Gujska, Elżbieta; Czarnowska, Marta; Klepacka, Joanna; Nowak, Fabian

    2016-03-01

    This study investigated the effects of storage and temperature duration on the stability of acrylamide (AA) and 5-hydroxymethylfurfural (HMF) in selected foods with long shelf-life. Products were analysed fresh and stored at temperatures of 4 and 25 °C after 6 and 12 months (with the exception of soft bread samples, which were analysed after 15 and 30 days). The AA and HMF contents were determined with RP-HPLC coupled to a diode array detector (DAD). AA and HMF were not stable in many processed plant products with a long shelf-life. The highest AA reduction and the largest increase in HMF content were observed in the samples stored at a higher temperature (25 °C) for 12 months. It was found that an initial water activity of 0.4 is favourable to HMF formation and that AA reduction may be considerably greater in stored products with a low initial water activity. The kind of product and its composition may also have a significant impact on acrylamide content in stored food. In the final period of storage at 25 °C, acrylamide content in 100% cocoa powder, instant baby foods, 20% cocoa powder and instant coffee was 51, 39, 35 and 33% lower than in products before storage, respectively. It was observed that a large quantity of ε-NH2 and SH groups of amino acids in some products can be assumed as the reason for the significant AA degradation. PMID:26768597

  4. OPTIMIZATION OF PRODUCTION OF 5-HYDROXYMETHYLFURFURAL FROM GLUCOSE IN A WATER: ACETONE BIPHASIC SYSTEM

    Directory of Open Access Journals (Sweden)

    A. D. M. Mendonça

    2015-06-01

    Full Text Available Abstract5-Hydroxymethylfurfural (HMF is considered to be an important building block for biorefineries and has a high potential for the production of chemicals and fuels. Production of HMF from glucose was studied using phosphoric acid as catalyst, in a water:acetone system with volume ratio of 1:2 and NaCl. An experimental design was applied to examine the influence of temperature, time and concentration of catalyst on the HMF yield. HMF yields of more than 50 % were obtained when using 200 ºC, 8.4 min and 0.8% of catalyst. The temperature is the main factor influencing the HMF yield.

  5. CONVERSION OF FRUCTOSE TO 5-HYDROXYMETHYLFURFURAL WITH A FUNCTIONALIZED IONIC LIQUID

    Directory of Open Access Journals (Sweden)

    Hao Ma,

    2011-11-01

    Full Text Available Fructose can be efficiently converted to 5-hydroxymethylfurfural by using the functionalized ionic liquid 3-(2-chloroethyl-1-methylimidazolium chloride as both solvent and catalyst in the presence of water. This work advances the field and is distinct from earlier efforts in the sense that the observed yields of HMF from fructose are rather high and the reaction conditions rather mild and neutral in the complete absence of acidic additives (HMF yield 76% at 100 oC in 40 minutes.

  6. Platinum-cobalt bimetallic nanoparticles in hollow carbon nanospheres for hydrogenolysis of 5-hydroxymethylfurfural

    Science.gov (United States)

    Wang, Guang-Hui; Hilgert, Jakob; Richter, Felix Herrmann; Wang, Feng; Bongard, Hans-Josef; Spliethoff, Bernd; Weidenthaler, Claudia; Schüth, Ferdi

    2014-03-01

    The synthesis of 2,5-dimethylfuran (DMF) from 5-hydroxymethylfurfural (HMF) is a highly attractive route to a renewable fuel. However, achieving high yields in this reaction is a substantial challenge. Here it is described how PtCo bimetallic nanoparticles with diameters of 3.6 ± 0.7 nm can solve this problem. Over PtCo catalysts the conversion of HMF was 100% within 10 min and the yield to DMF reached 98% after 2 h, which substantially exceeds the best results reported in the literature. Moreover, the synthetic method can be generalized to other bimetallic nanoparticles encapsulated in hollow carbon spheres.

  7. Development and validation of an HPLC method to determine metabolites of 5-hydroxymethylfurfural (5-HMF).

    Science.gov (United States)

    Hardt-Stremayr, Magdalena; Bernaskova, Marketa; Hauser, Stefanie; Kunert, Olaf; Guo, Xinghua; Stephan, Janette; Spreitz, Josef; Lankmayr, Ernst; Schmid, Martin G; Wintersteiger, Reinhold

    2012-10-01

    The food component 5-hydroxymethylfurfural is supposed to have antioxidative properties and is therefore used as an acting agent in a novel anticancer infusion solution, named Karal®, and an oral supplementation. Previous studies showed that after oral and intravenous application, the substance is completely decomposed to its metabolites: 5-hydroxymethylfuroic acid, 2,5-furandicarboxylic acid, and N-(hydroxymethyl)furoyl glycine. The formation of a fourth metabolite, namely 5-sulphoxymethylfurfural, is still not clarified according to literature. Due to commercial unavailability, synthesis of 5-sulphoxymethylfurfural was conducted and a synthesis procedure for N-(hydroxymethyl)furoyl glycine had to be developed. Identification of the synthesised compounds was proven by LC-MS and NMR. An appropriate HPLC method was established to obtain good separation of the four possible metabolic substances and 5-hydroxymethylfurfural within 12 min via a HILIC column (150 × 4.6 mm, 5 μm) using a gradient grade system switching from mobile phase A (ACN/ammonium formate 100 mM, pH 2.35, 95:5, v/v) to mobile phase B (ACN/ammonium formate 100 mM, pH 2.35, 85:15, v/v). The procedure was afterward validated following ICH guidelines in terms of selectivity, linearity, precision, LOD, and LOQ. PMID:22941583

  8. Simultaneous determination of 5-hydroxymethylfurfural and patulin in apple juice by reversed-phase liquid chromatography.

    Science.gov (United States)

    Gökmen, V; Acar, J

    1999-06-25

    A rapid, simple and economical method was described for the simultaneous determination of 5-hydroxymethylfurfural (HMF) and patulin in apple juice. The sample was extracted with ethyl acetate and the extract was then cleaned up by extraction with a sodium carbonate solution. Then HMF and patulin were determined by reversed-phase liquid chromatography using a C18 column and a photodiode array detector. HMF and patulin could be completely resolved by using the mixture water-acetonitrile (99:1, v/v) as the mobile phase with a flow rate of 1.0 ml/min. Mean recoveries of HMF ranged from 86% to 100% with an overall mean of 94%, that of patulin ranged from 94% to 125% with an overall mean of 103%, for different spiking levels. The limits of detection for HMF and patulin in apple juice were found to be < 0.01 mg/l and < 5 micrograms/l, respectively. PMID:10431352

  9. An Unexpected Reaction between 5-Hydroxymethylfurfural and Imidazolium-Based Ionic Liquids at High Temperatures

    Directory of Open Access Journals (Sweden)

    Zongbao K. Zhao

    2011-10-01

    Full Text Available A new compound was detected during the production of 5-hydroxymethylfurfural (HMF from glucose and cellulose in the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl at high temperatures. Further experiments found that it was derived from the reaction of HMF with [Bmim]Cl. The structure of new compound was established as 1-butyl-2-(5’-methyl-2’-furoylimidazole (BMI based on nuclear magnetic resonance and mass spectrometry analysis, and a possible mechanism for its formation was proposed. Reactions of HMF with other imidazolium-based ionic liquids were performed to check the formation of BMI. Our results provided new insights in terms of side reactions between HMF and imidazolium-based ionic liquids, which should be valuable for designing better processes for the production of furans using biomass and related materials.

  10. Efficient dehydration of fructose to 5-hydroxymethylfurfural catalyzed by a recyclable sulfonated organic heteropolyacid salt.

    Science.gov (United States)

    Qu, Yongshui; Huang, Chongpin; Zhang, Jie; Chen, Biaohua

    2012-02-01

    The dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) with room temperature ionic liquids (ILs) is a way of producing liquid fuels from renewable resources, but separation of products and IL is energy intensive. In this work, a heteropolyacid salt of an IL-forming cation functionalized with a propanesulfonate group, 1-(3-sulfonicacid)propyl-3-methyl imidazolium phosphotungstate ([MIMPS](3)PW(12)O(40)), was used as a catalyst-rather than as a solvent-in the conversion of fructose to 5-HMF. The maximum yield of 5-HMF was 99.1% at 120°C after 2h using sec-butanol as solvent, and the catalyst was separated from the reaction mixture by a simple process at the end of the reaction and reused six times without loss of activity. PMID:22201545

  11. An RP-HPLC determination of 5-hydroxymethylfurfural in honey The case of strawberry tree honey.

    Science.gov (United States)

    Spano, Nadia; Casula, Lucia; Panzanelli, Angelo; Pilo, Maria I; Piu, Paola C; Scanu, Roberta; Tapparo, Andrea; Sanna, Gavino

    2006-02-15

    The use of the RP-HPLC official method of the International Honey Commission (IHC) for the determination of 5-hydroxymethylfurfural (HMF) in strawberry tree honey (Arbutus unedo, a typical Sardinian honey) has brought to light a specific and heavy chromatographic interference that prevents accurate quantification. The interference has been identified as homogentisic acid (HA), i.e. the marker of the botanical origin of the honey. For this reason, an alternative RP-HPLC method is proposed. The bias-free method allows a complete separation of HMF from HA to the baseline level and is faster and more precise than the RP-HPLC official method: the detection and quantification limits are 1.9 and 4.0mgkg(-1), respectively, whereas the repeatability is ca. 2% in the HMF concentration range of 5-140mgkg(-1). PMID:18970477

  12. Direct Conversion of Mono- and Polysaccharides into 5-Hydroxymethylfurfural Using Ionic-Liquid Mixtures.

    Science.gov (United States)

    Siankevich, Sviatlana; Fei, Zhaofu; Scopelliti, Rosario; Jessop, Philip G; Zhang, Jiaguang; Yan, Ning; Dyson, Paul J

    2016-08-23

    Platform chemicals are usually derived from petrochemical feedstocks. A sustainable alternative commences with lignocellulosic biomass, a renewable feedstock, but one that is highly challenging to process. Ionic liquids (ILs) are able to solubilize biomass and, in the presence of catalysts, convert the biomass into useful platform chemicals. Herein, we demonstrate that mixtures of ILs are powerful systems for the selective catalytic transformation of cellulose into 5-hydroxymethylfurfural (HMF). Combining ILs with continuous HMF extraction into methyl-isobutyl ketone or 1,2-dimethoxyethane, which form a biphase with the IL mixture, allows the online separation of HMF in high yield. This one-step process is operated under relatively mild conditions and represents a significant step forward towards sustainable HMF production. PMID:27345462

  13. Efficient Conversion of Carbohydrates to 5-Hydroxymethylfurfural (HMF Using ZrCl4 Catalyst in Nitromethane

    Directory of Open Access Journals (Sweden)

    Raju S. Thombal

    2014-09-01

    Full Text Available Solvent nitromethane along with a variety of metal chloride and mineral acids as catalyst were studied for the synthesis of 5-Hydroxymethylfurfural (HMF, a key precursor in the formation of alternative fuel 2,5-dimethylfuran (DMF and other value added chemicals. Reaction time, temperature and catalyst concentration were also systematically studied to achieve highest HMF formation. Among the carbohydrates studied for HMF synthesis, D-fructose and inulin were found particularly most productive yielding >70% and with 100% selectivity using ZrCl4 in nitromethane at 100 oC during 3h. Readily available reagents, solvents, and simple reaction conditions could mark this process promising for HMF formation from biomass.

  14. Recyclable Magnetite Nanoparticle Catalyst for One-Pot Conversion of Cellobiose to 5-Hydroxymethylfurfural in Water

    Directory of Open Access Journals (Sweden)

    Anuja Bhalkikar

    2015-01-01

    Full Text Available Environmentally benign and easily recoverable magnetite nanoparticles (Fe3O4 NPs were demonstrated to catalyze the one-pot conversion of cellobiose, a glucose disaccharide, to 5-hydroxymethylfurfural (5-HMF. The conversion was achieved in water under hydrothermal conditions. The catalytic activity of Fe3O4 NPs surpassed those of iron (II and iron (III chlorides in this reaction. Optimized cellobiose conversion reactions catalyzed with Fe3O4 NPs gave the highest 5-HMF yields of 23.4 ± 0.6% at 160°C for 24 hours. After three reuses, the Fe3O4 NP catalyst retained its catalytic activity with similar 5-HMF yields, demonstrating the recyclability of this eco-friendly catalyst in water.

  15. Analysis of 5-hydroxymethylfurfural in foods by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Teixidó, E; Santos, F J; Puignou, L; Galceran, M T

    2006-11-24

    A new, simple and selective method for the analysis of 5-hydroxymethylfurfural (HMF) in foods by gas chromatography coupled to mass spectrometry (GC-MS) is proposed. Several derivatising procedures based on the formation of an HMF silylated derivative using different reagents were studied. Among the derivatising reagents examined, N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA) provided the best derivatisation yield. Sample clean-up was also optimised, using either liquid-liquid extraction with dichloromethane or solid-phase extraction (SPE) with several commercially available cartridges, and the best results were obtained using ENV+ cartridges. Quality parameters such as day-to-day and run-to-run precision (RSD<10%), linearity (between 25 and 700 ng g(-1)) and detection limit (6 ng g(-1)) were established. This method was successfully applied to the analysis of HMF content in several Spanish food samples from a local market, such as jam, honey, orange juice and bakery products. PMID:17010355

  16. Acrylamide and 5-hydroxymethylfurfural formation in reconstituted potato chips during frying.

    Science.gov (United States)

    Miao, YuTian; Zhang, HuanJie; Zhang, LuLu; Wu, SiJia; Sun, YiJia; Shan, Yu; Yuan, Yuan

    2014-12-01

    In our present paper, the effect of water activity and processing conditions in reconstituted potato chips was considered as a model to investigate the changes of acrylamide (AA) and 5-hydroxymethylfurfural (HMF). The results suggested that the formation of AA and HMF was highly correlated with frying temperature and time. Water activity could also influence the formation of AA and HMF. Meanwhile, the formation of HMF has significant correlation with the formation of AA in reconstituted potato chips. A typical exponential growth curve was observed by plotting AA levels vs HMF content which were all determined under different heating condition: [Formula: see text]. The model could be used as a tool for estimating the formation of AA when the content of HMF was known. PMID:25477673

  17. Lysosome: regulator of lipid degradation pathways

    OpenAIRE

    Settembre, Carmine; Ballabio, Andrea

    2014-01-01

    Autophagy is a catabolic pathway that has a fundamental role in the adaptation to fasting and primarily relies on the activity of the endolysosomal system, to which the autophagosome targets substrates for degradation. Recent studies have revealed that the lysosomal–autophagic pathway plays an important part in the early steps of lipid degradation. In this review, we discuss the transcriptional mechanisms underlying co-regulation between lysosome, autophagy, and other steps of lipid catabolis...

  18. Characterisation of viscosity, colour, 5-hydroxymethylfurfural content and diastase activity in raw rape honey (Brassica napus) at different temperatures.

    Science.gov (United States)

    Kędzierska-Matysek, Monika; Florek, Mariusz; Wolanciuk, Anna; Skałecki, Piotr; Litwińczuk, Anna

    2016-04-01

    The effect of heating at various temperatures (30, 40, 50, 60, 70 and 80 °C) on dynamic viscosity, colour, 5-hydroxymethylfurfural (5-HMF) concentration and diastase activity of raw rape honey were assessed. In fresh honey, moisture, ash, free acidity, pH and electrical conductivity averaged 185.3 g kg(-1), 1.2 g kg(-1), 18.71 mEq kg(-1), 4.2 and 0.25 mS cm(-1), respectively. Heating significantly (p ≤ 0.05) increased lightness (L*), yellowness (b*), chroma (C*), hue (h°) values, but decreased redness (a*). The viscosity at 20 °C (33.6 Pa s) differed significantly (p ≤ 0.01) with those at 30, 40 and 50 °C (8.2, 2.5, and 1.6 Pa s, respectively). Diastase activity decreased concomitant with heating at higher temperatures. Honey heated at 80 °C for 15 min showed the maximum increase of 5-HMF content, with an average of 1.9 mg kg(-1) (62 %), compared to unheated samples. Heating for 15 min between 50 °C and 80 °C did not significantly degrade the quality of the honey, but, slightly enhanced formation of 5-HMF and reduced the diastase activity. PMID:27413239

  19. Conversion of fructose-glucose mixtures to 5-hydroxymethylfurfural (HMF) in a biphasic slug-flow microreactor setup

    NARCIS (Netherlands)

    Deuss, Peter; Zhang, Zheng; Lubach, Bouke; Hacking, Jasper; Yue, Jun; Heeres, Hero

    2016-01-01

    The production of platform chemicals from lignocellulosic biomass is one of the main targets to enable future sustainable chemical industry.[1][2] 5-hydroxymethylfurfural (HMF) has been identified as one of the most important platform chemicals that can be obtained from the sugar fraction of lignoce

  20. Experimental and Modeling Studies on the Conversion of Inulin to 5-Hydroxymethylfurfural Using Metal Salts in Water

    NARCIS (Netherlands)

    Fachri, Boy Arief; Rasrendra, Carolus Borromeus; Heeres, Hero Jan

    2015-01-01

    Inulin, a plant polysaccharide consisting of mainly d-fructose units, is considered an interesting feed for 5-hydroxymethylfurfural (HMF), a top 12 bio-based chemical. We here report an exploratory experimental study on the use of a wide range of homogeneous metal salts as catalysts for the conversi

  1. Selective Aerobic Oxidation of 5-Hydroxymethylfurfural in Water Over Solid Ruthenium Hydroxide Catalysts with Magnesium-Based Supports

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

    Solid catalyst systems comprised of ruthenium hydroxide supported on magnesium-based carrier materials (spinel, magnesium oxide and hydrotalcite) were investigated for the selective, aqueous aerobic oxidation of the biomass-derived chemical 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid...

  2. Acrylamide and 5-hydroxymethylfurfural formation during baking of biscuits: NaCl and temperature-time profile effects and kinetics

    NARCIS (Netherlands)

    Fels, van der H.J.; Capuano, E.; Nguyen, H.T.; Mogol, B.A.; Kocadagli, T.; Goncuoglu Tas, N.; Hamzalioglu, A.; Boekel, van M.A.J.S.; Gokmen, V.

    2014-01-01

    The present study aimed to investigate the effect of recipe and temperature–time on the formation of acrylamide and 5-hydroxymethylfurfural (HMF) during biscuit baking. Baking experiments were performed with biscuits of two different recipes, with and without NaCl, at 180 °C, 190 °C and 200 °C. Acry

  3. Experimental and modeling studies on the acid-catalyzed conversion of inulin to 5-hydroxymethylfurfural in water

    NARCIS (Netherlands)

    Fachri, B.A.; Abdilla, R. M.; Rasrendra, C. B.; Heeres, Hero

    2016-01-01

    Inulin is considered as an attractive feed for the synthesis of 5-hydroxymethylfurfural (HMF), an important biobased platform chemical with high application potential. We here report a systematic study to optimize the HMF yield from inulin in a batch reactor for reactions in water using sulphuric ac

  4. Kinetic mechanism of an aldehyde reductase of Saccharomyces cerevisiae that relieves toxicity of furfural and 5-hydroxymethylfurfural

    Science.gov (United States)

    An effective means of relieving the toxicity of furan aldehydes, furfural (FFA) and 5-hydroxymethylfurfural (HMF), on fermenting organisms is essential for achieving efficient fermentation of lignocellulosic biomass to ethanol and other products. Ari1p, an aldehyde reductase from Saccharomyces cerev...

  5. Inoculum pre-treatment affects the fermentative activity of hydrogen-producing communities in the presence of 5-hydroxymethylfurfural.

    Science.gov (United States)

    Bellucci, Micol; Botticella, Giuseppe; Francavilla, Matteo; Beneduce, Luciano

    2016-01-01

    To enhance the productivity of mixed microbial cultures for fermentative bio-hydrogen production, chemical-physical pre-treatments of the original seed are needed to suppress the activity of hydrogen (H2)-consuming microbes. This approach might influence negatively the composition and diversity of the hydrogen-producing community with consequences on the functional stability of the H2-producing systems in case of perturbations. In this study, we aimed at investigating the effect of different types of pre-treatment on the performance of hydrogen production systems in the presence of an inhibitor, such as 5-hydroxymethylfurfural (HMF). The efficiency and the microbial community structure of batch reactors amended with HMF and inoculated with non-pretreated and pretreated (acid, heat shock, and aeration) anaerobic sludge were evaluated and compared with control systems. The type of pre-treatments influenced the microbial community assembly and activity in inhibited systems, with significant effect on the performance. Cumulative H2 production tests showed that the pre-aerated systems (control and HMF inhibited) were the most efficient, while the difference of the lag phase of the pre-acidified control and HMF-added test was negligible. Analyses of the structure of the enriched microbial community in the systems through PCR-denaturing gradient gel electrophoresis (DGGE) followed by band sequencing revealed that the differences in performance were mostly related to shifts in the metabolic pathways rather than in the predominant species. In conclusion, the findings suggest that the use of specific inoculum pre-treatment could contribute to regulate the metabolic activity of the fermentative H2-producing bacteria in order to enhance the bio-energy production. PMID:26428244

  6. Inoculum pre-treatment affects the fermentative activity of hydrogen-producing communities in the presence of 5-hydroxymethylfurfural.

    Science.gov (United States)

    Bellucci, Micol; Botticella, Giuseppe; Francavilla, Matteo; Beneduce, Luciano

    2016-01-01

    To enhance the productivity of mixed microbial cultures for fermentative bio-hydrogen production, chemical-physical pre-treatments of the original seed are needed to suppress the activity of hydrogen (H2)-consuming microbes. This approach might influence negatively the composition and diversity of the hydrogen-producing community with consequences on the functional stability of the H2-producing systems in case of perturbations. In this study, we aimed at investigating the effect of different types of pre-treatment on the performance of hydrogen production systems in the presence of an inhibitor, such as 5-hydroxymethylfurfural (HMF). The efficiency and the microbial community structure of batch reactors amended with HMF and inoculated with non-pretreated and pretreated (acid, heat shock, and aeration) anaerobic sludge were evaluated and compared with control systems. The type of pre-treatments influenced the microbial community assembly and activity in inhibited systems, with significant effect on the performance. Cumulative H2 production tests showed that the pre-aerated systems (control and HMF inhibited) were the most efficient, while the difference of the lag phase of the pre-acidified control and HMF-added test was negligible. Analyses of the structure of the enriched microbial community in the systems through PCR-denaturing gradient gel electrophoresis (DGGE) followed by band sequencing revealed that the differences in performance were mostly related to shifts in the metabolic pathways rather than in the predominant species. In conclusion, the findings suggest that the use of specific inoculum pre-treatment could contribute to regulate the metabolic activity of the fermentative H2-producing bacteria in order to enhance the bio-energy production.

  7. Conversion of red-algae Gracilaria verrucosa to sugars, levulinic acid and 5-hydroxymethylfurfural.

    Science.gov (United States)

    Jeong, Gwi-Taek; Ra, Chae Hun; Hong, Yong-Ki; Kim, Joong Kyun; Kong, In-Soo; Kim, Sung-Koo; Park, Don-Hee

    2015-02-01

    This study employed a statistical methodology to investigate the optimization of conversion conditions and evaluate the reciprocal interaction of reaction factors related to the process of red-algae Gracilaria verrucosa conversion to sugars (glucose, galactose), levulinic acid and 5-hydroxymethylfurfural (5-HMF) by acidic hydrolysis. Overall, the conditions optimized for glucose formation included a higher catalyst concentration than did those for galactose, and these conditions for galactose were similar to those for 5-HMF. Levulinic acid production, meanwhile, was optimized at a higher reaction temperature, a higher catalyst concentration, and a longer reaction time than was glucose, galactose or 5-HMF production. By this approach, the optimal yields (and reaction conditions) for glucose, galactose, levulinic acid, and 5-HMF were as follows: glucose 5.29 g/L (8.46 wt%) (reaction temperature 160 °C, catalyst concentration 1.92%, reaction time 20 min), galactose 18.38 g/L (29.4 wt%) (160 °C, 1.03%, 20 min), levulinic acid 14.65 g/L (18.64 wt%) (180.9 °C, 2.85%, 50 min), and 5-HMF 3.74 g/L (5.98 wt%) (160.5 °C, 1%, 20 min).

  8. Sulfonic acid heterogeneous catalysts for dehydration of C6-monosaccharides to 5-hydroxymethylfurfural in dimethyl sulfoxide

    Institute of Scientific and Technical Information of China (English)

    Gabriel Morales; Juan A.Melero; Marta Paniagua; Jose Iglesias; Blanca Hernández; María Sanz

    2014-01-01

    Sulfonic acid-functionalized heterogeneous catalysts have been evaluated in the catalytic dehydra-tion of C6 monosaccharides into 5-hydroxymethylfurfural (HMF) using dimethyl sulfoxide (DMSO) as solvent. Sulfonic commercial resin Amberlyst-70 was the most active catalyst, which was as-cribed to its higher concentration of sulfonic acid sites as compared with the other catalysts, and it gave 93 mol%yield of HMF from fructose in 1 h. With glucose as the starting material, which is a much more difficult reaction, the reaction conditions (time, temperature, and catalyst loading) were optimized for Amberlyst-70 by a response surface methodology, which gave a maximum HMF yield of 33 mol%at 147°C with 23 wt%catalyst loading based on glucose and 24 h reaction time. DMSO promotes the dehydration of glucose into anhydroglucose, which acts as a reservoir of the substrate to facilitate the production of HMF by reducing side reactions. Catalyst reuse without a regeneration treatment showed a gradual but not very significant decay in catalytic activity.

  9. Catalytic conversion of inulin and fructose into 5-hydroxymethylfurfural by lignosulfonic acid in ionic liquids.

    Science.gov (United States)

    Xie, Haibo; Zhao, Zongbao K; Wang, Qian

    2012-05-01

    In this work, we found that lignosulfonic acid (LS), which is a waste byproduct from the paper industry, in ionic liquids (ILs) can catalyze the dehydration of fructose and inulin into 5-hydroxymethylfurfural (HMF) efficiently, which is a promising potential substitute for petroleum-based building blocks. The effects of reaction time, temperature, catalyst loading, and reusability of the catalytic system were studied. It was found that a 94.3% yield of HMF could be achieved in only 10 min at 100 °C under mild conditions. The reusability study of the LS-IL catalytic system after removal of HMF by ethyl acetate extraction demonstrated that the catalytic activity decreased from 77.4 to 62.9% after five cycles and the catalytic activity could be recovered after simply removing the accumulated humins by filtration after adding ethanol to the LS-ILs. The integrated utilization of a biorenewable feedstock, catalyst, and ILs is an example of an ideal green chemical process. PMID:22517537

  10. Direct Catalytic Conversion of Cellulose to 5-Hydroxymethylfurfural Using Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Sanan Eminov

    2016-10-01

    Full Text Available Cellulose is the single largest component of lignocellulosic biomass and is an attractive feedstock for a wide variety of renewable platform chemicals and biofuels, providing an alternative to petrochemicals and petrofuels. This potential is currently limited by the existing methods of transforming this poorly soluble polymer into useful chemical building blocks, such as 5-hydroxymethylfurfural (HMF. Ionic liquids have been used successfully to separate cellulose from the other components of lignocellulosic biomass and so the use of the same medium for the challenging transformation of cellulose into HMF would be highly attractive for the development of the biorefinery concept. In this report, ionic liquids based on 1-butyl-3-methylimidazolium cations [C4C1im]+ with Lewis basic (X = Cl− and Brønsted acidic (X = HSO4− anions were used to investigate the direct catalytic transformation of cellulose to HMF. Variables probed included the composition of the ionic liquid medium, the metal catalyst, and the reaction conditions (temperature, substrate concentration. Lowering the cellulose loading and optimising the temperature achieved a 58% HMF yield after only one hour at 150 °C using a 7 mol % loading of the CrCl3 catalyst. This compares favourably with current literature procedures requiring much longer reactions times or approaches that are difficult to scale such as microwave irradiation.

  11. The Highly Selective and Near-Quantitative Conversion of Glucose to 5-Hydroxymethylfurfural Using Ionic Liquids

    Science.gov (United States)

    Eminov, Sanan; Brandt, Agnieszka; Wilton-Ely, James D. E. T.

    2016-01-01

    A number of ionic liquids have been shown to be excellent solvents for lignocellulosic biomass processing, and some of these are particularly effective in the production of the versatile chemical building block 5-hydroxymethylfurfural (HMF). In this study, the production of HMF from the simple sugar glucose in ionic liquid media is discussed. Several aspects of the selective catalytic formation of HMF from glucose have been elucidated using metal halide salts in two distinct ionic liquids, 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium hydrogen sulfate as well as mixtures of these, revealing key features for accelerating the desired reaction and suppressing byproduct formation. The choice of ionic liquid anion is revealed to be of particular importance, with low HMF yields in the case of hydrogen sulfate-based salts, which are reported to be effective for HMF production from fructose. The most successful system investigated in this study led to almost quantitative conversion of glucose to HMF (90% in only 30 minutes using 7 mol% catalyst loading at 120°C) in a system which is selective for the desired product, has low energy intensity and is environmentally benign. PMID:27711238

  12. Bifunctional polyacrylonitrile fiber-mediated conversion of sucrose to 5-hydroxymethylfurfural in mixed-aqueous systems.

    Science.gov (United States)

    Shi, Xian-Lei; Zhang, Min; Lin, Huikun; Tao, Minli; Li, Yongdan; Zhang, Wenqin

    2015-03-01

    A highly efficient catalytic system composed of a bifunctional polyacrylonitrile fiber (PANF-PA[BnBr]) and a metal chloride was employed to produce 5-hydroxymethylfurfural (HMF) from sucrose in mixed-aqueous systems. The promoter of PANF-PA[BnBr] incorporates protonic acid groups that promote the hydrolysis of the glycosidic bond to convert sucrose into glucose and fructose, and then catalyzes fructose dehydration to HMF, while the ammonium moiety may promote synergetically with the metal chloride the isomerization of glucose to fructose and transfer HMF from the aqueous to the organic phase. The detailed characterization by elemental analysis, FTIR spectroscopy, and SEM confirmed the rangeability of the fiber promoter during the modification and utilization processes. Excellent results in terms of high yield (72.8%) of HMF, superior recyclability (6 cycles) of the process, and effective scale-up and simple separation procedures of the catalytic system were obtained. Moreover, the prominent features (high strength, good flexibility, etc.) of the fibers are very attractive for fix-bed reactor. PMID:25573698

  13. Simultaneous determination of melamine and 5-hydroxymethylfurfural in milk by capillary electrophoresis with diode array detection.

    Science.gov (United States)

    Chen, Zhijun; Yan, Xiaomei

    2009-10-14

    This article describes the development of a simple analytical approach for the simultaneous determination of melamine and 5-hydroxymethylfurfural (HMF) in milk samples using capillary electrophoresis (CE) with diode array detection (DAD) for the first time. Ultraviolet absorption at wavelengths of 214 and 280 nm was applied for the detection of melamine and HMF, respectively. Milk samples were extracted with 1% trichloroacetic acid using a high-speed blender and ultrasonication. After centrifugation and filtration, the extract was analyzed by CE-DAD directly. Micellar electrokinetic capillary chromatography was employed as the separation mode by adding sodium dodecyl sulfate (SDS) to the electrolyte. Under optimal separation conditions, melamine, HMF, and interferents were well resolved. The linear dynamic ranges were 0.05-100 microg/mL for melamine (R(2) = 0.9996) and 0.1-100 microg/mL for HMF (R(2) = 0.9997). The assay detection limits were 0.047 microg/mL and 0.067 microg/mL for melamine and HMF, respectively. Satisfactory results were obtained for the assay recovery rate and repeatability. The proposed method was successfully applied for the analysis of melamine and HMF in real milk samples, and the results of melamine were comparable to those obtained using HPLC-UV reference method. PMID:19761188

  14. Glucose transformation to 5-hydroxymethylfurfural in acidic ionic liquid: A quantum mechanical study.

    Science.gov (United States)

    Arifin; Puripat, Maneeporn; Yokogawa, Daisuke; Parasuk, Vudhichai; Irle, Stephan

    2016-01-30

    Isomerization and transformation of glucose and fructose to 5-hydroxymethylfurfural (HMF) in both ionic liquids (ILs) and water has been studied by the reference interaction site model self-consistent field spatial electron density distribution (RISM-SCF-SEDD) method coupled with ab initio electronic structure theory, namely coupled cluster single, double, and perturbative triple excitation (CCSD(T)). Glucose isomerization to fructose has been investigated via cyclic and open chain mechanisms. In water, the calculations support the cyclic mechanism of glucose isomerization; with the predicted activation free energy is 23.8 kcal mol(-1) at experimental condition. Conversely, open ring mechanism is more favorable in ILs with the energy barrier is 32.4 kcal mol(-1) . Moreover, the transformation of fructose into HMF via cyclic mechanism is reasonable; the calculated activation barriers are 16.0 and 21.5 kcal mol(-1) in aqueous and ILs solutions, respectively. The solvent effects of ILs could be explained by the decomposition of free energies and radial distribution functions of solute-solvent that are produced by RISM-SCF-SEDD. PMID:26453901

  15. Catalytic conversion of carbohydrates to 5-hydroxymethylfurfural from the waste liquid of acid hydrolysis NCC.

    Science.gov (United States)

    Sun, Yonghui; Liu, Pengtao; Liu, Zhong

    2016-05-20

    The principal goal of this work was to reuse the carbohydrates and recycle sulfuric acid in the waste liquid of acid hydrolysis nanocrystalline cellulose (NCC). Therefore, in this work, the optimizations of further hydrolysis of waste liquid of acid hydrolysis NCC and catalytic conversion of L4 to 5-hydroxymethylfurfural (5-HMF) were studied. Sulfuric acid was separated by spiral wound diffusion dialysis (SWDD). The results revealed that cellulose can be hydrolyze to glucose absolutely under the condition of temperature 35 °C, 3 h, and sulfuric acid's concentration 62 wt%. And 78.3% sulfuric acid was recovered by SWDD. The yield of 5-HMF was highest in aqueous solution under the optimal condition was as follows, temperature 160 °C, 3 h, and sulfuric acid's concentration 12 wt%. Then the effect of biphasic solvent systems catalytic conversion and inorganic salt as additives were still examined. The results showed that both of them contributed to prepare 5-HMF. The yield and selectivity of 5-HMF was up to 21.0% and 31.4%, respectively. PMID:26917388

  16. Influence of Salts on the Partitioning of 5-Hydroxymethylfurfural in Water/MIBK.

    Science.gov (United States)

    Mohammad, Sultan; Held, Christoph; Altuntepe, Emrah; Köse, Tülay; Sadowski, Gabriele

    2016-04-28

    This study investigates the influence of electrolytes on the performance of extracting 5-hydroxymethylfurfural (HMF) from aqueous media using methyl isobutyl ketone (MIBK). For that purpose, liquid-liquid phase equilibria (LLE) of quaternary systems containing HMF, water, MIBK and salts were measured at atmospheric pressure and 298.15 K. The salts under investigation were composed of one of the anions NO(3-), SO4(2-), Cl(-), or CH3COO(-) and of one of the alkali cations Li(+), Na(+), or K(+). On the basis of these LLE data, the partition coefficient of HMF between the aqueous and the MIBK phase KHMF was determined. It could be shown that KHMF significantly depends on the kind and concentration of the added salt. Weak electrolytes (e.g., sulfates, acetates) caused salting-out, whereas nitrates caused salting-in of HMF to the aqueous phase. Unexpectedly, LiCl caused salting-out at low LiCl concentrations and salting-in at LiCl concentrations higher than 3 mol/kgH2O. The model electrolyte perturbed-chain SAFT (ePC-SAFT) was used to predict the salt influence on the LLE in the quaternary systems water/MIBK/HMF/salt in good agreement with the experimental data. On the basis of ePC-SAFT, it could be concluded that the different salting-out/salting-in behavior of the various salts is mainly caused by their different tendency to form ion pairs in aqueous solutions. PMID:27027570

  17. Dehydration of Carbohydrates to 5-Hydroxymethylfurfural in Ionic Liquids Catalyzed by Hexachlorotriphosphazene

    Institute of Scientific and Technical Information of China (English)

    宋金良; 张斌斌; 史敬华; 马珺; 杨冠英; 韩布兴

    2012-01-01

    Development of efficient catalysts for the dehydration of carbohydrates to produce 5-hydroxymethylfurfural (HMF) is a very attractive topic. In this work, dehydration of fructose catalyzed by three organic molecules, includ- ing hexachlorotriphosphazene (N3P3CI6), trichloromelamine (C3N6H3CI3) and N-bromosuccinimide (NBS), was studied in ionic liquids. It was discovered that the three organic molecules had high activity in accelerating the de- hydration of fructose and N3P3C16 was the most efficient catalyst among them. The effects of amount of catalysts, temperature, solvents, reaction time, and substrate/solvent weight ratio on the reaction were investigated using N3P3C16 as the catalyst and 1-butyl-3-methylimidazolium chloride ([Bmim]C1) as the solvent. It was demonstrated that the N3P3C16/[Bmim]CI catalytic system was very effective for catalyzing the reaction. The yield of HMF could reach 92.8% in 20 rain at the optimized conditions and the N3P3C16/[Bmim]C1 system could be reused. Further study indicated that the N3P3C16/[Bmim]CI system was also effective for the dehydration of sucrose and inulin and satisfactory yield could be obtained at suitable conditions.

  18. Catalytic hydrolysis of lignocellulosic biomass into 5-hydroxymethylfurfural in ionic liquid.

    Science.gov (United States)

    Wang, Pan; Yu, Hongbing; Zhan, Sihui; Wang, Shengqiang

    2011-03-01

    Production of 5-hydroxymethylfurfural (HMF) from cellulose catalyzed by solid acids and metal chlorides was studied in the 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) under microwave irradiation. Among the applied catalysts, the use of CrCl(3)/LiCl resulted in the highest yield of HMF. The effects of catalyst dosage (mole ratio of catalyst to glucose units in the feedstock) and reaction temperature on HMF yields were investigated to obtain optimal process conditions. With the 1:1 mol ratio of catalyst to glucose unit, the HMF yield reached 62.3% at 160°C for 10 min. Untreated wheat straw was also investigated as feedstock to produce HMF for the practical use of raw biomass, in which the HMF yield was comparable to that from pure cellulose. After the extraction of HMF, [BMIM]Cl and CrCl(3)/LiCl could be reused and exhibited no activity loss after three successive runs. PMID:21232942

  19. Glucose dehydration to 5-hydroxymethylfurfural in a biphasic system over solid acid foams.

    Science.gov (United States)

    Ordomsky, Vitaly V; van der Schaaf, John; Schouten, Jaap C; Nijhuis, T Alexander

    2013-09-01

    A solid acid foam-structured catalyst based on a binderless zirconium phosphate (ZrPO) coating on aluminum foam was prepared. The catalyst layer was obtained by performing a multiple washcoating procedure of ZrPO slurry on the anodized aluminum foam. The effect of the pretreatment of ZrPO, the concentration of the slurry, and the amount of coating on the properties of the foam was studied. The catalytic properties of the prepared foams have been evaluated in the dehydration of glucose to 5-hydroxymethylfurfural (HMF) in a biphasic reactor. The catalytic behavior of ZrPO foam-based catalysts was studied in a rotating foam reactor and compared with that of bulk ZrPO. The effect of a silylation procedure on the selectivity of the process was shown over bulk and foam catalysts. This treatment resulted in a higher selectivity due to the deactivation of unselective Lewis acid sites. Addition of methylisobutylketone leads to extraction of HMF from the aqueous phase and stabilization of the selectivity to HMF over bulk ZrPO. A more intensive contact of the foam with the aqueous and organic phases leads to an increase in the selectivity and resistance to deactivation of the foam in comparison with a bulk catalyst. PMID:23616489

  20. Over-expression of NADH-dependent oxidoreductase (fucO) for increasing furfural or 5-hydroxymethylfurfural tolerance

    Science.gov (United States)

    Miller, Elliot N.; Zhang, Xueli; Yomano, Lorraine P.; Wang, Xuan; Shanmugam, Keelnatham T.; Ingram, Lonnie O'Neal

    2015-10-13

    The subject invention pertains to the discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural. This allows for a new approach to improve furfural tolerance in bacterial and/or yeast cells used to produce desired products. Thus, novel biocatalysts (bacterial, fungal or yeast cells) exhibiting increased tolerance to furfural and 5-hydroxymethylfurfural (5-HMF) are provided as are methods of making and using such biocatalysts for the production of a desired product.

  1. Bioactivation of food genotoxicants 5-hydroxymethylfurfural and furfuryl alcohol by sulfotransferases from human, mouse and rat: a comparative study.

    Science.gov (United States)

    Sachse, Benjamin; Meinl, Walter; Sommer, Yasmin; Glatt, Hansruedi; Seidel, Albrecht; Monien, Bernhard H

    2016-01-01

    5-Hydroxymethylfurfural (HMF) and furfuryl alcohol (FFA) are moderately potent rodent carcinogens that are present in thermally processed foodstuffs. The carcinogenic effects were hypothesized to originate from sulfotransferase (SULT)-mediated bioactivation yielding DNA-reactive and mutagenic sulfate esters, a confirmed metabolic pathway of HMF and FFA in mice. It is known that orthologous SULT forms substantially differ in substrate specificity and tissue distribution. This could influence HMF- and FFA-induced carcinogenic effects. Here, we studied HMF and FFA sulfoconjugation by 30 individual SULT forms of humans, mice and rats. The catalytic efficiencies (k cat/K M) of HMF sulfoconjugation of human SULT1A1 (13.7 s(-1) M(-1)), mouse Sult1a1 (15.8 s(-1) M(-1)) and 1d1 (4.8 s(-1) M(-1)) and rat Sult1a1 (5.3 s(-1) M(-1)) were considerably higher than those of all other SULT forms investigated (≤0.73 s(-1 )M(-1)). FFA sulfoconjugation was monitored using adenosine as a nucleophilic scavenger for the reactive 2-sulfoxymethylfuran (t 1/2 = 20 s at 37 °C). The resulting adduct N (6)-((furan-2-yl)methyl)-adenosine (N (6)-MF-A) was quantified by isotope-dilution UPLC-MS/MS. The rates of N (6)-MF-A formation showed that hSULT1A1 and its orthologues in mice and rats were also the most important contributors to FFA sulfoconjugation in each of the species. Taken together, the catalytic capacity of hSULT1A1 is comparable to that of mSult1a1 in mice, the species in which carcinogenic effects of HMF and FFA were detected. This is of primary concern due to the expression of hSULT1A1 in many different tissues. PMID:25370010

  2. Organocatalyzed One-Step Synthesis of Functionalized N-Alkyl-Pyridinium Salts from Biomass Derived 5-Hydroxymethylfurfural.

    Science.gov (United States)

    Sowmiah, Subbiah; Veiros, Luís F; Esperança, José M S S; Rebelo, Luís P N; Afonso, Carlos A M

    2015-11-01

    An efficient and scalable method has been developed for the synthesis of N-alkylpyridinium salts from biomass derived 5-hydroxymethylfurfural and alkyl amines using a catalytic amount of formic acid. This protocol is also extended to various diamines providing the exclusive formation of mono-N-alkylpyridinium salts. In addition, the mechanism for the formation of pyridinium salts was studied by DFT and using H2(18)O isotope labeled experiments showing no incorporation of (18)O in the product. PMID:26493742

  3. Roles of the Yap1 transcription factor and antioxidants in Saccharomyces cerevisiae's tolerance to furfural and 5-hydroxymethylfurfural, which function as thiol-reactive electrophiles generating oxidative stress.

    Science.gov (United States)

    Kim, Daehee; Hahn, Ji-Sook

    2013-08-01

    Development of the tolerance of Saccharomyces cerevisiae strains to furfural and 5-hydroxymethylfurfural (HMF) is an important issue for cellulosic ethanol production. Although furfural and HMF are known to induce oxidative stress, the underlying mechanisms are largely unknown. In this study, we show that both furfural and HMF act as thiol-reactive electrophiles, thus directly activating the Yap1 transcription factor via the H2O2-independent pathway, depleting cellular glutathione (GSH) levels, and accumulating reactive oxygen species in Saccharomyces cerevisiae. However, furfural showed higher reactivity than did HMF toward GSH in vitro and in vivo. In line with such toxic mechanisms, overexpression of YAP1(C620F), a constitutively active mutant of YAP1, and Yap1 target genes encoding catalases (CTA1 and CTT1) increased tolerance to furfural and HMF. However, increasing GSH levels by overexpression of genes for GSH biosynthesis (GSH1 and GLR1) or by the exogenous addition of GSH to the culture medium enhanced tolerance to furfural but not to HMF.

  4. Roles of the Yap1 transcription factor and antioxidants in Saccharomyces cerevisiae's tolerance to furfural and 5-hydroxymethylfurfural, which function as thiol-reactive electrophiles generating oxidative stress.

    Science.gov (United States)

    Kim, Daehee; Hahn, Ji-Sook

    2013-08-01

    Development of the tolerance of Saccharomyces cerevisiae strains to furfural and 5-hydroxymethylfurfural (HMF) is an important issue for cellulosic ethanol production. Although furfural and HMF are known to induce oxidative stress, the underlying mechanisms are largely unknown. In this study, we show that both furfural and HMF act as thiol-reactive electrophiles, thus directly activating the Yap1 transcription factor via the H2O2-independent pathway, depleting cellular glutathione (GSH) levels, and accumulating reactive oxygen species in Saccharomyces cerevisiae. However, furfural showed higher reactivity than did HMF toward GSH in vitro and in vivo. In line with such toxic mechanisms, overexpression of YAP1(C620F), a constitutively active mutant of YAP1, and Yap1 target genes encoding catalases (CTA1 and CTT1) increased tolerance to furfural and HMF. However, increasing GSH levels by overexpression of genes for GSH biosynthesis (GSH1 and GLR1) or by the exogenous addition of GSH to the culture medium enhanced tolerance to furfural but not to HMF. PMID:23793623

  5. Critical Influence of 5-Hydroxymethylfurfural Aging and Decomposition on the Utility of Biomass Conversion in Organic Synthesis.

    Science.gov (United States)

    Galkin, Konstantin I; Krivodaeva, Elena A; Romashov, Leonid V; Zalesskiy, Sergey S; Kachala, Vadim V; Burykina, Julia V; Ananikov, Valentine P

    2016-07-11

    Spectral studies revealed the presence of a specific arrangement of 5-hydroxymethylfurfural (5-HMF) molecules in solution as a result of a hydrogen-bonding network, and this arrangement readily facilitates the aging of 5-HMF. Deterioration of the quality of this platform chemical limits its practical applications, especially in synthesis/pharma areas. The model drug Ranitidine (Zantac®) was synthesized with only 15 % yield starting from 5-HMF which was isolated and stored as an oil after a biomass conversion process. In contrast, a much higher yield of 65 % was obtained by using 5-HMF isolated in crystalline state from an optimized biomass conversion process. The molecular mechanisms responsible for 5-HMF decomposition in solution were established by NMR and ESI-MS studies. A highly selective synthesis of a 5-HMF derivative from glucose was achieved using a protecting group at O(6) position.

  6. Separation of galactose, 5-hydroxymethylfurfural and levulinic acid in acid hydrolysate of agarose by nanofiltration and electrodialysis.

    Science.gov (United States)

    Kim, Jae Hyung; Na, Jeong-Geol; Yang, Ji-Won; Chang, Yong Keun

    2013-07-01

    A two-stage membrane process for the separation of galactose, 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) has been proposed. The first step of nanofiltration (NF) is to remove 5-HMF and LA from galactose solution obtained by the hydrolysis of agarose, the main component of red algal galactan for the reduction of its microbial toxicity. 5-HMF and LA are inhibitory to fermentation but at the same time useful compounds themselves with many applications. The second step of electrodialysis (ED) is to separate 5-HMF and LA in the permeate from NF. More than 91% of 5-HMF and up to 62% of LA could be removed from agarose hydrolysate, while galactose was almost completely retained by NF. Further removal of LA was expected to be possible with no loss of galactose by operating the NF process in a diafiltration mode. 5-HMF and LA could be effectively separated from each other by ED. PMID:23672940

  7. Catalytic Performance of Zeolite-Supported Vanadia in the Aerobic Oxidation of 5-hydroxymethylfurfural to 2,5- diformylfuran

    DEFF Research Database (Denmark)

    Sádaba, Irantzu; Gorbanev, Yury; Kegnæs, Søren;

    2013-01-01

    /Vis spectrophotometry. The H-beta zeolite catalysts were found to contain highly dispersed vanadium oxide species at all loadings, and provided the highest reaction selectivity towards DFF and the lowest metal leaching of the examined systems. In particular, 1 wt % V2O5/H-beta was found to be a stable, recyclable......The catalytic performance of zeolite-supported vanadia catalysts was examined for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) in organic solvents such as N,N-dimethylformamide (DMF), methyl isobutyl ketone, toluene, trifluorotoluene and DMSO. Catalysts based...... on the four different zeolite supports H-beta, H-Y, H-mordenite, and H-ZSM-5 with 1–10 wt% vanadia loading were prepared and characterized by nitrogen physisorption, X-ray powder diffraction, scanning electron  microscopy, ammonia temperature-programmed desorption, Raman spectroscopy and UV...

  8. Base-Free Aqueous-Phase Oxidation of 5-Hydroxymethylfurfural over Ruthenium Catalysts Supported on Covalent Triazine Frameworks.

    Science.gov (United States)

    Artz, Jens; Palkovits, Regina

    2015-11-01

    The base-free aqueous-phase oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxilic acid (FDCA) was performed at 140 °C and 20 bar of synthetic air as the oxidant. Ru clusters supported on covalent triazine frameworks (CTFs) enabled superior conversion (99.9%) and FDCA yields in comparison to other support materials such as activated carbon and γ-Al2O3 after only 1 h. The properties of the CTFs such as pore volume, specific surface area, and polarity could be tuned by using different monomers. These material properties influence the catalytic activity of Ru/CTF significantly as mesoporous CTFs showed superior activity compared to microporous materials, whereas high polarities provide further beneficial effects. The recyclability of the prepared Ru/CTF catalysts was comparable to that of Ru/C at high conversions and product yields. Nevertheless, minor deactivation in five successive recycling experiments was observed. PMID:26482331

  9. Chlorogenic acid increased 5-hydroxymethylfurfural formation when heating fructose alone or with aspartic acid at two pH levels.

    Science.gov (United States)

    Zhang, Zhenhua; Zou, Yueyu; Wu, Taigang; Huang, Caihuan; Pei, Kehan; Zhang, Guangwen; Lin, Xiaohua; Bai, Weibin; Ou, Shiyi

    2016-01-01

    Chlorogenic acid (CGA) is a phenolic acid that ubiquitously exists in fruits. This work aims to investigate whether and how CGA influences HMF formation during heating fructose alone, or with an amino acid. The results showed that that CGA increased 5-hydroxymethylfurfural (HMF) formation. At pH 5.5 and 7.0, the addition of 5.0 μmol/ml CGA increased HMF formation by 49.4% and 25.2%, respectively when heating fructose alone, and by 9.0% and 16.7%, respectively when heating fructose with aspartic acid. CGA significantly increased HMF formation by promoting 3-deoxosone formation, and its conversion to HMF by inhibiting HMF elimination, especially in the Maillard reaction system. A comparison of the catalytic capacity of CGA with its six analogous compounds showed that both its di-hydroxyphenyl and carboxyl groups function in increasing HMF formation. PMID:26213045

  10. Critical Influence of 5-Hydroxymethylfurfural Aging and Decomposition on the Utility of Biomass Conversion in Organic Synthesis.

    Science.gov (United States)

    Galkin, Konstantin I; Krivodaeva, Elena A; Romashov, Leonid V; Zalesskiy, Sergey S; Kachala, Vadim V; Burykina, Julia V; Ananikov, Valentine P

    2016-07-11

    Spectral studies revealed the presence of a specific arrangement of 5-hydroxymethylfurfural (5-HMF) molecules in solution as a result of a hydrogen-bonding network, and this arrangement readily facilitates the aging of 5-HMF. Deterioration of the quality of this platform chemical limits its practical applications, especially in synthesis/pharma areas. The model drug Ranitidine (Zantac®) was synthesized with only 15 % yield starting from 5-HMF which was isolated and stored as an oil after a biomass conversion process. In contrast, a much higher yield of 65 % was obtained by using 5-HMF isolated in crystalline state from an optimized biomass conversion process. The molecular mechanisms responsible for 5-HMF decomposition in solution were established by NMR and ESI-MS studies. A highly selective synthesis of a 5-HMF derivative from glucose was achieved using a protecting group at O(6) position. PMID:27271823

  11. Experimental and Kinetic Modeling Studies on the Sulfuric Acid Catalyzed Conversion of D-Fructose to 5-Hydroxymethylfurfural and Levulinic Acid in Water

    NARCIS (Netherlands)

    Fachri, Boy A.; Abdilla, Ria M.; van de Bovenkamp, Henk H.; Rasrendra, Carolus B.; Heeres, Hero J.

    2015-01-01

    Levulinic acid (LA) and 5-hydroxymethylfurfural (HMF) have been identified as promising biomass-derived platform chemicals. A kinetic study on the conversion of D-fructose to HMF and LA in water using sulfuric acid as the catalyst has been performed in batch setups. The experiments were carried out

  12. From 5-Hydroxymethylfurfural (HMF) to Polymer Precursors : Catalyst Screening Studies on the Conversion of 1,2,6-hexanetriol to 1,6-hexanediol

    NARCIS (Netherlands)

    Buntara, Teddy; Noel, Sébastien; Phua, Pim Huat; Melián-Cabrera, Ignacio; Vries, Johannes G. de; Heeres, Hero J.

    2012-01-01

    1,6-hexanediol (1) is an important polymer precursor for the polyester industry. In this paper, exploratory catalyst screening studies on the synthesis of 1 from 1,2,6-hexanetriol (2) are described via two different routes. The latter is available by a two-step procedure from 5-hydroxymethylfurfural

  13. A kinetic study on the decomposition of 5-hydroxymethylfurfural into levulinic acid

    NARCIS (Netherlands)

    Girisuta, B.; Janssen, L. P. B. M.; Heeres, H. J.

    2006-01-01

    Levulinic acid (LA), accessible by the acid catalyzed degradation of biomass, is potentially a very versatile green intermediate chemical for the synthesis of various (bulk) chemicals for applications like fuel additives, polymers, and resin precursors. We report here a kinetic study on one of the k

  14. Direct Production of 5-Hydroxymethylfurfural via Catalytic Conversion of Simple and Complex Sugars over Phosphated TiO2.

    Science.gov (United States)

    Atanda, Luqman; Shrotri, Abhijit; Mukundan, Swathi; Ma, Qing; Konarova, Muxina; Beltramini, Jorge

    2015-09-01

    A water-THF biphasic system containing N-methyl-2-pyrrolidone (NMP) was found to enable the efficient synthesis of 5-hydroxymethylfurfural (HMF) from a variety of sugars (simple to complex) using phosphated TiO2 as a catalyst. Fructose and glucose were selectively converted to HMF resulting in 98 % and 90 % yield, respectively, at 175 °C. Cellobiose and sucrose also gave rise to high HMF yields of 94 % and 98 %, respectively, at 180 °C. Other sugar variants such as starch (potato and rice) and cellulose were also investigated. The yields of HMF from starch (80-85 %) were high, whereas cellulose resulted in a modest yield of 33 %. Direct transformation of cellulose to HMF in significant yield (86 %) was assisted by mechanocatalytic depolymerization-ball milling of acid-impregnated cellulose. This effectively reduced cellulose crystallinity and particle size, forming soluble cello-oligomers; this is responsible for the enhanced substrate-catalytic sites contact and subsequent rate of HMF formation. During catalyst recyclability, P-TiO2 was observed to be reusable for four cycles without any loss in activity. We also investigated the conversion of the cello-oligomers to HMF in a continuous flow reactor. Good HMF yield (53 %) was achieved using a water-methyl isobutyl ketone+NMP biphasic system.

  15. Experimental and Modeling Studies on the Conversion of Inulin to 5-Hydroxymethylfurfural Using Metal Salts in Water

    Directory of Open Access Journals (Sweden)

    Boy Arief Fachri

    2015-12-01

    Full Text Available Inulin, a plant polysaccharide consisting of mainly d-fructose units, is considered an interesting feed for 5-hydroxymethylfurfural (HMF, a top 12 bio-based chemical. We here report an exploratory experimental study on the use of a wide range of homogeneous metal salts as catalysts for the conversion of inulin to HMF in water. Best results were obtained using CuCl2. Activity-pH relations indicate that the catalyst activity of CuCl2 is likely related to Lewis acidity and not to Brönsted acidity. The effects of process conditions on HMF yield for CuCl2 were systematically investigated and quantified using a central composite design (160–180 °C, an inulin loading between 0.05 and 0.15 g/mL, CuCl2 concentration in range of 0.005–0.015 M, and a reaction time between 10 and 120 min. The highest experimental HMF yield in the process window was 30.3 wt. % (39 mol %, 180 °C, 0.05 g/mL inulin, 0.005 M CuCl2 and a reaction time of 10 min. The HMF yields were modelled using non-linear, multi variable regression and good agreement between experimental data and model were obtained.

  16. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    International Nuclear Information System (INIS)

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (–COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed

  17. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Saikat; Wu, Kevin C.-W., E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Kao, Hsien-Ming, E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemistry, National Central University, Chung-Li 32054, Taiwan (China)

    2014-11-01

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (–COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and {sup 13}C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

  18. Removal and recovery of furfural, 5-hydroxymethylfurfural, and acetic acid from aqueous solutions using a soluble polyelectrolyte.

    Science.gov (United States)

    Carter, Brian; Gilcrease, Patrick C; Menkhaus, Todd J

    2011-09-01

    In the cellulosic ethanol process, furfural, 5-hydroxymethylfurfural (HMF), and acetic acid are formed during the high temperature acidic pretreatment step needed to convert biomass into fermentable sugars. These compounds can inhibit cellulase enzymes and fermentation organisms at relatively low concentrations (≥ 1 g/L). Effective removal of these inhibitory compounds would allow the use of more severe pretreatment conditions to improve sugar yields and lead to more efficient fermentations; if recovered and purified, they could also be sold as valuable by-products. This study investigated the separation of aldhehydes (furfural and HMF) and organic acid (acetic acid) inhibitory compounds from simple aqueous solutions by using polyethyleneimene (PEI), a soluble cationic polyelectrolyte. PEI added to simple solutions of each inhibitor at a ratio of 1 mol of functional group to 1 mol inhibitor removed up to 89.1, 58.6, and 81.5 wt% of acetic acid, HMF, and furfural, respectively. Furfural and HMF were recovered after removal by washing the polyelectrolyte/inhibitor complex with dilute sulfuric acid solution. Recoveries up to 81.0 and 97.0 wt% were achieved for furfural and HMF, respectively. The interaction between PEI and acetic acid was easily disrupted by the addition of chloride ions, sulfate ions, or hydroxide ions. The use of soluble polymers for the removal and recovery of inhibitory compounds from biomass slurries is a promising approach to enhance the efficiency and economics of an envisioned biorefinery. PMID:21455937

  19. Sn-MCM-41 as Efficient Catalyst for the Conversion of Glucose into 5-Hydroxymethylfurfural in Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Qing Xu

    2013-11-01

    Full Text Available Recently, much attention has been paid to the development of technologies that facilitate the conversion of biomass into platform chemicals such as 5-hydroxymethylfurfural (5-HMF. In this paper, a tin-containing silica molecular sieve (Sn-MCM-41 was found to act as a bifunctional heterogeneous catalyst for the efficient conversion of glucose into 5-HMF in ionic liquid. In the presence of [EMIM]Br, the yield of 5-HMF converted from glucose reached 70% at 110 °C after 4 h. During the reaction, the active center of the catalyst first catalyzed the isomerization of glucose into fructose and then the dehydration of fructose into 5-HMF. After the reaction, the heterogeneous catalyst Sn-MCM-41 could be easily recovered and reused without a significant loss in activity. The catalyst Sn-MCM-41 was also able to catalyze the conversion of fructose into 5-HMF at an 80% yield. Moreover, the low toxicity of the Sn-based catalyst makes the method a greener approach for the conversion of saccharides into 5-HMF.

  20. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    Science.gov (United States)

    Dutta, Saikat; Kao, Hsien-Ming; Wu, Kevin C.-W.

    2014-11-01

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (-COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

  1. Rapid Method for the Determination of 5-Hydroxymethylfurfural and Levulinic Acid Using a Double-Wavelength UV Spectroscopy

    Directory of Open Access Journals (Sweden)

    Junhua Zhang

    2013-01-01

    Full Text Available This study reports on a rapid method for the determination of levulinic acid (LA and 5-hydroxymethylfurfural (HMF in acid hydrolyze system of glucose based on UV spectroscopy. It was found that HMF and LA have a maximum absorption at the wavelengths of 284 nm and 266 nm, respectively, in a water medium, and the absorptions of HMF and LA at 284 nm and 266 nm follow Beer’s law very well. However, it was found that a major spectral interference species will arise in the quantification of HMF and LA; nonetheless, this interference can be eliminated through the absorption treatment of charcoal. Therefore, both HMF and LA can be quantified with a double-wavelength technique. The repeatability of the method had a relative standard deviation of less than 4.47% for HMF and 2.25% for LA; the limit of quantification (LOQ was 0.017 mmol/L for HMF and 4.68 mmol/L for LA, and the recovery ranged from 88% to 116% for HMF and from 94% to 105% for LA. The present method is simple, rapid, and accurate. It is suitable to use in the research of the preparation of HMF and LA in biorefinery area.

  2. Catalytic Upgrading of 5-Hydroxymethylfurfural to Drop-in Biofuels by Solid Base and Bifunctional Metal-Acid Catalysts.

    Science.gov (United States)

    Bohre, Ashish; Saha, Basudeb; Abu-Omar, Mahdi M

    2015-12-01

    Design and synthesis of effective heterogeneous catalysts for the conversion of biomass intermediates into long chain hydrocarbon precursors and their subsequent deoxygenation to hydrocarbons is a viable strategy for upgrading lignocellulose into distillate range drop-in biofuels. Herein, we report a two-step process for upgrading 5-hydroxymethylfurfural (HMF) to C9 and C11 fuels with high yield and selectivity. The first step involves aldol condensation of HMF and acetone with a water tolerant solid base catalyst, zirconium carbonate (Zr(CO3 )x ), which gave 92 % C9 -aldol product with high selectivity at nearly 100 % HMF conversion. The as-synthesised Zr(CO3 )x was analysed by several analytical methods for elucidating its structural properties. Recyclability studies of Zr(CO3 )x revealed a negligible loss of its activity after five consecutive cycles over 120 h of operation. Isolated aldol product from the first step was hydrodeoxygenated with a bifunctional Pd/Zeolite-β catalyst in ethanol, which showed quantitative conversion of the aldol product to n-nonane and 1-ethoxynonane with 40 and 56 % selectivity, respectively. 1-Ethoxynonane, a low oxygenate diesel range fuel, which we report for the first time in this paper, is believed to form through etherification of the hydroxymethyl group of the aldol product with ethanol followed by opening of the furan ring and hydrodeoxygenation of the ether intermediate. PMID:26549016

  3. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    Directory of Open Access Journals (Sweden)

    Saikat Dutta

    2014-11-01

    Full Text Available This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs functionalized with carboxylic acid (–COOH group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

  4. Determination of 5-hydroxymethylfurfural using derivatization combined with polymer monolith microextraction by high-performance liquid chromatography.

    Science.gov (United States)

    Wu, Jian-Yuan; Shi, Zhi-Guo; Feng, Yu-Qi

    2009-05-27

    A simple and sensitive method for the determination of 5-hydroxymethylfurfural (HMF) in coffee, honey, beer, Coke, and urine by high-performance liquid chromatography (HPLC) is presented. This method is based on the formation of the 2,4-dinitrophenylhydrazone of HMF and subsequent polymer monolith microextraction (PMME) of this derivative. A poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EGDMA) monolithic capillary column was selected as the extraction medium. Several parameters affecting the derivatization of HMF with 2,4-dinitrophenylhydrazine (DNPH) followed by extraction of the derivative were optimized. The procedure is simple and offers high sensitivity and specificity since the derivative of HMF is well preconcentrated by PMME with poly(MAA-co-EGDMA) monolith and well separated from the other components of the samples under examination. The recoveries in coffee, honey, beer, Coke, and urine samples were in the range of 83.9-110.8% spiked at different levels with HMF. The inter- and intraday precisions were less than 10%. The LOD (S/N = 3) and LOQ (S/N = 10) for HMF were 1.0 ng/mL and 3.4 ng/mL, respectively. PMID:19397264

  5. Simultaneous quantitative determination of alpha-ketoglutaric acid and 5-hydroxymethylfurfural in human plasma by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Wagner, Bernhard M; Donnarumma, Fabrizio; Wintersteiger, Reinhold; Windischhofer, Werner; Leis, Hans J

    2010-04-01

    Alpha-ketoglutaric acid (alpha-KG) and 5-hydroxymethylfurfural (5-HMF) are currently under investigation as promising cancer cell damaging agents. A method for the simultaneous quantitative determination of alpha-KG and 5-HMF in human plasma was established for screening these compounds in human plasma. Plasma samples were directly treated with O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride to form the corresponding oximes, thus facilitating subsequent liquid-liquid extraction. After formation of the trimethylsilyl ethers, samples were analyzed by gas chromatography with electron ionization mass spectrometry. Stable isotope labeled standards were used, the preparation of (13)C(6)-5-HMF is described. Limits of quantitation were set to 0.938 microg/mL for alpha-KG and 0.156 microg/mL for 5-HMF. Inter-day accuracy was < or = 93.7% (alpha-KG) and < or = 92.8% (5-HMF). Inter-day precision was < or = 6.0% (alpha-KG) and < or = 4.6% (5-HMF). The method has been successfully applied to pharmacokinetic profiling of the compounds after intravenous application. PMID:20155414

  6. Synthesis of 5-hydroxymethylfurfural (HMF) by acid catalyzed dehydration of glucose-fructose mixtures

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard; Ringborg, Rolf Hoffmeyer; Grotkjær, Thomas;

    2015-01-01

    -products: soluble humins, glucose dimers, anhydroglucose, and formic acid. The reaction conditions in four different reactor configurations were optimized and compared using the kinetic model. It was found that a recirculating reactor setup is preferable, where the equilibrium controlled by-products (anhydroglucose...... a detailed experimental investigation a reaction network was proposed, and subsequently the corresponding kinetic model was fitted to experimental data in order to obtain estimates of the reaction kinetic parameters. The kinetic model is capable of predicting the formation of HMF along with the important by...... and glucose dimers) are recirculated to the dehydration reactor. The model predicts an HMF selectivity of close to 70% in a recirculating reactor at conditions where HMF degradation is avoided....

  7. Microbial PAH-Degradation in Soil: Degradation Pathways and Contributing Factors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-Xiang; CHENG Shu-Pei; ZHU Cheng-Jun; SUN Shi-Lei

    2006-01-01

    Adverse effects on the environment and high persistence in the microbial degradation and environmental fate of polycyclic aromatic hydrocarbons (PAHs) are motivating interest. Many soil microorganisms can degrade PAHs and use various metabolic pathways to do so. However, both the physio-chemical characteristics of compounds as well as the physical, chemical, and biological properties of soils can drastically influence the degradation capacity of naturally occurring microorganisms for field bioremediation. Modern biological techniques have been widely used to promote the efficiency of microbial PAH-degradation and make the biodegradation metabolic pathways more clear. In this review microbial degradation of PAHs in soil is discussed, with emphasis placed on the main degradation pathways and the environmental factors affecting biodegradation.

  8. One pot production of 5-hydroxymethylfurfural with high yield from cellulose by a Brønsted-Lewis-surfactant-combined heteropolyacid catalyst.

    Science.gov (United States)

    Zhao, Shun; Cheng, Mingxing; Li, Junzi; Tian, Juan; Wang, Xiaohong

    2011-02-21

    A Brønsted-Lewis-surfactant-combined heteropolyacid (HPA) Cr[(DS)H(2)PW(12)O(40)](3) has been synthesized, and is used as a heterogeneous catalyst for the conversion of cellulose to 5-hydroxymethylfurfural in one pot within 2 h at 150 °C with 77.1% conversion and 52.7% yield. This micellar HPA catalyst shows stability and can be recycled by simple separation process. PMID:21203610

  9. Single-step conversion of cellulose to 5-hydroxymethylfurfural (HMF), a versatile platform chemical

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yu; Brown, Heather M.; Huang, Xiwen; Zhou, Xiao Dong; Amonette, James E.; Zhang, Z. Conrad

    2009-06-20

    The ability to use cellulosic biomass as feedstock for the production of fuels and chemicals currently derived from petroleum depends critically on the development of effective low-temperature processes. While HMF, as a versatile platform chemical suitable for use in polymer synthesis or production of liquid biofuels, can currently be made from fructose and glucose, synthesis of HMF directly from raw natural cellulose represents the last major barrier toward the development of a sustainable HMF platform. Here we report an unprecedented single-step pathway that depolymerizes cellulose rapidly under mild conditions and converts the resulting glucose to hydroxymethylfurfural (HMF). A pair of metal chlorides (CuCl2 and CrCl2) dissolved in 1-ethyl-3-methylimidazolium chloride at temperatures of 80-120°C catalyzes cellulose depolymerization and the subsequent glucose conversion to HMF with 95% selectivity among recoverable products (at 56% HMF yield). Cellulose depolymerization, which can also be catalyzed by other metalchloride pairs such as CuCl2 paired with PdCl2, CrCl3, or FeCl3, occurs at a rate that is more than one order of magnitude faster than conventional acid-catalyzed hydrolysis. In contrast, single-metal chlorides at the same total loading showed low activity under similar conditions. Mechanistic studies suggest that the C2 hydrogen of the imidazolium ring is activated by the paired metal-chloride catalysts.

  10. Metabolic pathway engineering of the toluene degradation pathway

    OpenAIRE

    Regan, L.

    1995-01-01

    This thesis addresses the problem of how to examine a metabolic pathway and identify what are the key elements, specifically with respect to rate-limitation. The aim is to be able to analyze a pathway, identify the bottlenecks and implement genetic modifications to remove these bottlenecks. This is done by defining the system of interest and developing a predictive model using kinetic data. The model predictions can then be verified using fermentation data and genetic technique...

  11. Rapid conversion of cellulose to 5-hydroxymethylfurfural using single and combined metal chloride catalysts in ionic liquid%Rapid conversion of cellulose to5-hydroxymethylfurfural using single and combined metal chloride catalysts in ionic liquid

    Institute of Scientific and Technical Information of China (English)

    Hussein Abou-Yousef; El Barbary Hassan; Philip Steele

    2013-01-01

    Direct conversion of cellulose into 5-hydroxymethylfurfural (HMF) was performed by using single or combined metal chloride catalysts in 1-ethyl-3-methylimidazolium chloride ([EMIM] Cl) ionic liquid.Our study demonstrated formation of 2-furyl hydroxymethyl ketone (FHMK),and furfural (FF) simultaneously with the formation of HMF.Various reaction parameters were addressed to optimize yields of furan derivatives produced from cellulose by varying reaction temperature,time,and the type of metal chloride catalyst.Catalytic reaction by using FeCl3 resulted in 59.9% total yield of furan derivatives (HMF,FHMK,and FF) from cellulose.CrCl3 was the most effective catalyst for selective conversion of cellulose into HMF (35.6%) with less concentrations of FHMK,and FF.Improving the yields of furans produced from cellulose could be achieved via reactions catalyzed by different combinations of two metal chlorides.Further optimization was carried out to produce total furans yield 75.9% by using FeC13/CuCl2 combination.CrCl3/CuCl2 was the most selective combination to convert cellulose into HMF (39.9%) with total yield (63.8%) of fttrans produced from the reaction.The temperature and time of the catalytic reaction played an important role in cellulose conversion,and the yields of products.Increasing the reaction temperature could enhance the cellulose conversion and HMF yield for short reaction time intervals (5 ~ 20 min).

  12. Simultaneous determination of furfural, acetic acid, and 5-hydroxymethylfurfural in corncob hydrolysates using liquid chromatography with ultraviolet detection.

    Science.gov (United States)

    Dong, Bo-Yu; Chen, Ye-Fu; Zhao, Chang-Chun; Zhang, Shi-Jie; Guo, Xue-Wu; Xiao, Dong-Guang

    2013-01-01

    A single-laboratory validation study was conducted using HPLC for detecting and quantifying acetic acid, furfural, and 5-hydroxymethylfurfural (HMF) in corncob hydrolysates. A pretreatment procedure using dilute sulfuric acid was optimized for corncob hydrolysis. The final hydrolysates were analyzed by HPLC using a C18 RP column with aqueous 0.01% (v/v) H2SO4-CH3OH (95 + 5) as the mobile phase at a flow rate of 1 mL/min. The wavelengths for detecting the three compounds were changed to their optimal UV detection wavelengths at the time of elution. The wavelength detection adjustments were as follow: 205 nm (0 to 4 min); 284 nm (4 to 7 min); and 276 nm (7 to 10 min). Separation was achieved with a chromatographic run time of 10 min. The calibration curves for the three compounds had correlation coefficients (r2) > or = 99.8%. The analytical range, as defined by the calibration curves, was 0.5-10 mg/L for acetic acid, 0.4-22 mg/L for furfural, and 0.1-18 mg/L for HMF. The LODs for acetic acid, furfural, and HMF were estimated to be 0.05, 0.03, and 0.02 mg/L, respectively; the LOQs were 0.196, 0.135, and 0.074 mg/L, respectively. The RSD values for the intraday precision study ranged from 0.31 to 2.22%, and from 0.57 to 2.43% for the interday study. The mean recovery rates in all compounds were between 100.08 and 101.49%.

  13. Simultaneous determination of furfural, acetic acid, and 5-hydroxymethylfurfural in corncob hydrolysates using liquid chromatography with ultraviolet detection.

    Science.gov (United States)

    Dong, Bo-Yu; Chen, Ye-Fu; Zhao, Chang-Chun; Zhang, Shi-Jie; Guo, Xue-Wu; Xiao, Dong-Guang

    2013-01-01

    A single-laboratory validation study was conducted using HPLC for detecting and quantifying acetic acid, furfural, and 5-hydroxymethylfurfural (HMF) in corncob hydrolysates. A pretreatment procedure using dilute sulfuric acid was optimized for corncob hydrolysis. The final hydrolysates were analyzed by HPLC using a C18 RP column with aqueous 0.01% (v/v) H2SO4-CH3OH (95 + 5) as the mobile phase at a flow rate of 1 mL/min. The wavelengths for detecting the three compounds were changed to their optimal UV detection wavelengths at the time of elution. The wavelength detection adjustments were as follow: 205 nm (0 to 4 min); 284 nm (4 to 7 min); and 276 nm (7 to 10 min). Separation was achieved with a chromatographic run time of 10 min. The calibration curves for the three compounds had correlation coefficients (r2) > or = 99.8%. The analytical range, as defined by the calibration curves, was 0.5-10 mg/L for acetic acid, 0.4-22 mg/L for furfural, and 0.1-18 mg/L for HMF. The LODs for acetic acid, furfural, and HMF were estimated to be 0.05, 0.03, and 0.02 mg/L, respectively; the LOQs were 0.196, 0.135, and 0.074 mg/L, respectively. The RSD values for the intraday precision study ranged from 0.31 to 2.22%, and from 0.57 to 2.43% for the interday study. The mean recovery rates in all compounds were between 100.08 and 101.49%. PMID:24645500

  14. 蔗糖脱水制备5-羟甲基糠醛的研究%Preparation of 5-Hydroxymethylfurfural by Dehydration of Sucrose

    Institute of Scientific and Technical Information of China (English)

    孔珊珊; 刘仕伟; 李露; 于世涛

    2014-01-01

    研究了BrÖnsted-Lewis复合催化体系催化蔗糖脱水制备5-羟甲基糠醛,考察了反应条件对5-羟甲基糠醛收率的影响,最佳反应条件为:蔗糖2.0 g,复合催化体系HCl-CrCl3(质量比5:1)0.8 g,二甲基亚砜20 mL,反应时间30 min,反应温度200℃。在上述较佳反应条件下,蔗糖转化率为100%,5-羟甲基糠醛的收率达72.7%。此外,CrCl3对产物5-羟甲基糠醛具有良好的稳定性,在一定程度上可避免产物继续发生水合/脱羧反应而生成甲酸和乙酰丙酸。%The preparation of 5-hydroxymethylfurfural ( HMF ) from sucrose was studied in the presence of Br nsted-Lewis composite catalytic system. The effects of reaction conditions on the yield of 5-hydroxymethylfurfural were examined. The optimal reaction conditions were obtained as follows: sucrose 2. 0 g, composite catalytic system HCl-CrCl3(mass ratio 5:1) 0. 8 g , dimethyl sulfoxide 20 mL, reaction time 30 min and reaction temperature 200 ℃. Under the above conditions, the conversion of sucrose was 100 %, and the yield of 5-hydroxymethylfurfural reached 72. 7 %. Moreover, CrCl3 had a good stability on the product 5-hydroxymethylfurfural. It could avoid 5-hydroxymethylfurfural over-reacting to form formic acid and levulinic acid by the hydration/decarboxylation reaction to a certain extent.

  15. Phenanthrene-degrading pathway of Agrobacterium sp. Phx1

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; YUAN Hongli; WANG Shuangqing; HUANG Huaizeng

    2005-01-01

    The metabolic pathway of phenanthrene-degrading strain Agrobacterium sp. Phx1 was investigated. Phx1 almost was able to transform 100 υg/mL of phenanthrene completely in 1 day in broth media of beef extract-peptone (BP), Luria-Bertani (LB) and mineral salts media (MS), and LB and BP could promote the growth and degradation efficiency of Phx1. The GC-MS was employed to analyze the metabolites of the 1st, 3rd, 7th days of phenanthrene degradation in MS. As a result, the 1-Hydroxy-2-naphthoic acid (1H2N) and 1-naphthol (NOL) were detected in the metabolites of the 1st day. Only NOL was observed on the 3rd day and it disappeared on the 7th day. The accumulated NOL did not pertain to the defined pathway of phenanthrene degradation by bacteria. The further HPLC study confirmed the finding in GC-MS analysis and found the production of catechol (CAT) from o-phthalic acid (OPA) in the phenanthrene metabolizing, which has never been reported in the defined degrading pathways. This production was also evidenced by the production of CAT using OPA as substrate. All of our results showed that the Agrobacterium sp. Phx1 had a novel phenanthrene-degrading pathway.

  16. Preparation of 5-hydroxymethylfurfural from cellulose catalyzed by composite catalyst%复合催化剂降解纤维素制备5-羟甲基糠醛

    Institute of Scientific and Technical Information of China (English)

    袁玉国; 王景芸; 王强; 付霓虹; 周明东; 臧树良

    2016-01-01

    The degradation of microcrystalline cellulose(MCC) to 5-hydroxymethylfurfural in ionic liquid 1-allyl-3-methylimidazolium chloride([Amim]Cl) was studied with sulfoacid type cation exchange resin and CrCl3·6H2O as composite catalyst and microwave-assisted heating. The effects of catalyst dosage,reaction temperature,time and water dosage on the degradation were investigated. The results indicated that,MCC could be completely converted with the total reducing sugar yield of 75.2% and the highest 5-hydroxymethylfurfural yield of 53.0% under the conditions of sulfoacid type cation exchange resin and CrCl3·6H2O as the composite catalyst,ionic liquid[Amim]Cl as the solvent 2 g,MCC 0.1 g,m(resin):m(MCC) 1:1,n(CrCl3·6H2O):n(MCC) 1:10,reaction temperature 160℃ by microwave-assisted heating and reaction time 30 min.%以离子液体1-烯丙基-3-甲基咪唑氯盐([Amim]Cl)为溶剂,以磺酸型阳离子交换树脂和CrCl3·6H2O为复合催化剂,在微波辅助加热条件下采用一锅法降解微晶纤维素制备5-羟甲基糠醛,考察了催化剂加入量、反应温度、反应时间、加水量等反应条件对微晶纤维素降解反应的影响.实验结果表明,当[Amim]Cl用量为2 g、微晶纤维素质量为0.1 g、m(磺酸型阳离子交换树脂):m(微晶纤维素)=1:1、n(CrCl3·6H2O):n(微晶纤维素)=1:10、反应温度为160℃、反应时间为30 min、加水量为50 μL时,微晶纤维素可完全转化,同时总还原糖收率为75.2%,5-羟甲基糠醛收率最高可达53.0%.

  17. Trichloroethylene degradation by two independent aromatic-degrading pathways in Alcaligenes eutrophus JMP134.

    OpenAIRE

    Harker, A R; Kim, Y.

    1990-01-01

    The bacterium Alcaligenes eutrophus JMP134(pJP4) degrades trichloroethylene (TCE) by a chromosomal phenol-dependent pathway and by the plasmid-encoded 2,4-dichlorophenoxyacetic acid pathway. The two pathways were independent and exhibited different rates of removal and capacities for quantity of TCE removed. The phenol-dependent pathway was more rapid (0.2 versus 0.06 nmol of TCE removed per min per mg of protein) and consumed all detectable TCE. The 2,4-dichlorophenoxyacetic acid-dependent p...

  18. Epoxy Coenzyme A Thioester pathways for degradation of aromatic compounds.

    Science.gov (United States)

    Ismail, Wael; Gescher, Johannes

    2012-08-01

    Aromatic compounds (biogenic and anthropogenic) are abundant in the biosphere. Some of them are well-known environmental pollutants. Although the aromatic nucleus is relatively recalcitrant, microorganisms have developed various catabolic routes that enable complete biodegradation of aromatic compounds. The adopted degradation pathways depend on the availability of oxygen. Under oxic conditions, microorganisms utilize oxygen as a cosubstrate to activate and cleave the aromatic ring. In contrast, under anoxic conditions, the aromatic compounds are transformed to coenzyme A (CoA) thioesters followed by energy-consuming reduction of the ring. Eventually, the dearomatized ring is opened via a hydrolytic mechanism. Recently, novel catabolic pathways for the aerobic degradation of aromatic compounds were elucidated that differ significantly from the established catabolic routes. The new pathways were investigated in detail for the aerobic bacterial degradation of benzoate and phenylacetate. In both cases, the pathway is initiated by transforming the substrate to a CoA thioester and all the intermediates are bound by CoA. The subsequent reactions involve epoxidation of the aromatic ring followed by hydrolytic ring cleavage. Here we discuss the novel pathways, with a particular focus on their unique features and occurrence as well as ecological significance.

  19. Eletrochemical reduction of patulin and 5-hydroxymethylfurfural in both neutral and acid non-aqueous media. Their electroanalytical determination in apple juices.

    Science.gov (United States)

    Damián Chanique, Gerardo; Heraldo Arévalo, Alejandro; Alicia Zon, María; Fernández, Héctor

    2013-07-15

    The electro-reduction of patulin mycotoxin and 5-hydroxymethylfurfural at glassy carbon electrodes in acetonitrile +0.1 mol L(-1) tetrabutylammonium perchlorate, in both the absence and the presence of different aliquots of trifluoroacetic acid is reported. 5-hydroxymethylfurfural is the most common interference in the determination of patulin in products derived from apples. The electrochemical techniques were cyclic and square wave voltammetries, and controlled potential bulk electrolysis. The number of electrons exchanged in the patulin electro-reduction of n=1 could be inferred from controlled potential bulk electrolysis measurements. Ultraviolet-visible and infrared spectroscopies were used to identify patulin electro-reduction product/s. A value of (2.1±0.1)×10(-5) cm(2) s(-1) for the patulin diffusion coefficient was calculated from convoluted cyclic voltammograms. A method based on square wave voltammetry was developed for the quantitative determination of patulin in both fresh, and commercial apple juices in the presence of 5-hydroxymethylfurfural. Calibration curves obtained from solutions of the commercial reagent, and commercial apple juices were linear in the range from 3.0×10(-7) to 2.2×10(-5) mol L(-1). The lowest concentration measured experimentally for a signal to noise ratio of 3:1 was 3×10(-7) mol L(-1) (45 ppb) and a recovery percent of 84% was determined for commercial apple juices. This electroanalytical methodology appears as a good screening method for the determination of patulin in apple juices.

  20. Preparation of 5-hydroxymethylfurfural by dehydration of glucose%葡萄糖脱水制备5-羟甲基糠醛的研究

    Institute of Scientific and Technical Information of China (English)

    孔珊珊; 刘仕伟; 李露; 于世涛

    2013-01-01

    研究了Br(o)nsted-Lewis复合催化体系催化葡萄糖脱水制备5-羟甲基糠醛,详细考察了溶剂种类和用量、催化体系种类和用量、反应时间和反应温度等因素对5-羟甲基糠醛收率的影响,得到最佳工艺条件:葡萄糖2.0g,复合催化体系HCl-CrCl3[m(HCl)∶m(CrCl3·6H2O)=5∶1]0.6 g,正丁醇20 mL,反应时间15 min,反应温度200℃.在该反应条件下,5-羟甲基糠醛的收率达42.5%.结果表明,同单酸型的催化剂相比,复合催化体系更有利于葡萄糖脱水制备5-羟甲基糠醛.%The preparation of 5-hydroxymethylfurfural from glucose was studied in the presence of Br(o)nsted-Lewis composite catalytic system.The effects of reaction conditions,such as solvents,catalysts,reaction time and reaction temperature,on the yield of 5-hydroxymethylfurfural were examined.The optimum reaction conditions were obtained as follow:glucose 2.0 g,composite catalytic system HC1-CrCl3 (mass ratio 5 ∶ 1) 0.6 g,n-butyl alcohol 20 mL,reaction time 15 min and reaction temperature 200 ℃.Under above optimum conditions,the conversion of glucose was 90.4 %,and the yield of 5-hydroxymethylfurfural reached 42.5 %.The results indicated that,composite catalytic system is more conducible to preparation of 5-hydroxymethylfurfural by dehydration of glucose compared with the single-acid catalyst.

  1. Degradation of aromatic compounds and degradative pathway of 4-nitrocatechol by Ochrobactrum sp. B2.

    Science.gov (United States)

    Zhong, Qiuzan; Zhang, Haiyan; Bai, Wenqin; Li, Mei; Li, Baotong; Qiu, Xinghui

    2007-12-01

    The potential capacity of a soil methyl parathion-degrading bacterium strain, Ochrobactrum sp. B2, for degrading various aromatic compounds were investigated. The results showed B2 was capable of degrading diverse aromatic compounds, but amino-substituted benzene compounds, at a concentration up to 100 mg L(-1) in 4 days. B2 could use 4-nitrocatechol (4-NC) as a sole carbon and energy source with release of nitrite ion. The pathway for 4-NC degradation via 1,2,4-benzenetriol (BT) and hydroquinone (HQ) formation in B2 was proposed based on the identification and quantification of intermediates by gas chromatography-mass spectrometry (GC-MS), and high performance liquid chromatography (HPLC). Degradation studies carried out on a plasmid-cured derivative showed that the genes for 4-NC degradative pathway was plasmid-borne in B2, suggesting that B2 degrades both p-nitrophenol and 4-NC by enzymes encoded by genes on the same plasmid.

  2. Vacuole import and degradation pathway:Insights into a specialized autophagy pathway

    Institute of Scientific and Technical Information of China (English)

    Abbas; A; Alibhoy; Hui-Ling; Chiang

    2011-01-01

    Glucose deprivation induces the synthesis of pivotagluconeogenic enzymes such as fructose-1,6-bisphos-phatase, malate dehydrogenase, phosphoenolpyruvatecarboxykinase and isocitrate lyase in Saccharomycescerevisiae. However, following glucose replenishment,these gluconeogenic enzymes are inactivated and de-graded. Studies have characterized the mechanismsby which these enzymes are inactivated in response toglucose. The site of degradation of these proteins hasalso been ascertained to be dependent on the dura-tion of starvation. Glucose replenishment of short-termstarved cells results in these proteins being degradedin the proteasome. In contrast, addition of glucose tocells starved for a prolonged period results in theseproteins being degraded in the vacuole. In the vacuoledependent pathway, these proteins are sequestered inspecialized vesicles termed vacuole import and degra-dation (Vid). These vesicles converge with the endo-cytic pathway and deliver their cargo to the vacuolefor degradation. Recent studies have identified thatinternalization, as mediated by actin polymerization, isessential for delivery of cargo proteins to the vacuolefor degradation. In addition, components of the targetof rapamycin complex 1 interact with cargo proteins during glucose starvation. Furthermore, Tor1p dissoci-ates from cargo proteins following glucose replenish-ment. Future studies will be needed to elaborate on the importance of internalization at the plasma membrane and the subsequent import of cargo proteins into Vid vesicles in the vacuole dependent degradation pathway.

  3. Kynurenine pathway in psychosis: evidence of increased tryptophan degradation.

    LENUS (Irish Health Repository)

    Barry, Sandra

    2009-05-01

    The kynurenine pathway of tryptophan degradation may serve to integrate disparate abnormalities heretofore identified in research aiming to elucidate the complex aetiopathogenesis of psychotic disorders. Post-mortem brain tissue studies have reported elevated kynurenine and kynurenic acid in the frontal cortex and upregulation of the first step of the pathway in the anterior cingulate cortex of individuals with schizophrenia. In this study, we examined kynurenine pathway activity by measuring tryptophan breakdown, a number of pathway metabolites and interferon gamma (IFN-gamma), which is the preferential activator of the first-step enzyme, indoleamine dioxygenase (IDO), in the plasma of patients with major psychotic disorder. Plasma tryptophan, kynurenine pathway metabolites were measured using high-performance liquid chromatography (HPLC) in 34 patients with a diagnosis on the psychotic spectrum (schizophrenia or schizoaffective disorder) and in 36 healthy control subjects. IFN-gamma was measured using enzyme-linked immunosorbent assay (ELISA). The mean tryptophan breakdown index (kynurenine\\/tryptophan) was significantly higher in the patient group compared with controls (P < 0.05). IFN-gamma measures did not differ between groups (P = 0.23). No relationship was found between measures of psychopathology, symptom severity and activity in the first step in the pathway. A modest correlation was established between the tryptophan breakdown index and illness duration. These results provide evidence for kynurenine pathway upregulation, specifically involving the first enzymatic step, in patients with major psychotic disorder. Increased tryptophan degradation in psychoses may have potential consequences for the treatment of these disorders by informing the development of novel therapeutic compounds.

  4. Iodinated contrast media electro-degradation: Process performance and degradation pathways

    International Nuclear Information System (INIS)

    The electrochemical degradation of six of the most widely used iodinated contrast media was investigated. Batch experiments were performed under constant current conditions using two DSA® electrodes (titanium coated with a proprietary and patented mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum). The degradation removal never fell below 85% (at a current density of 64 mA/cm2 with a reaction time of 150 min) when perchlorate was used as the supporting electrolyte; however, when sulphate was used, the degradation performance was above 80% (at a current density of 64 mA/cm2 with a reaction time of 150 min) for all of the compounds studied. Three main degradation pathways were identified, namely, the reductive de-iodination of the aromatic ring, the reduction of alkyl aromatic amides to simple amides and the de-acylation of N-aromatic amides to produce aromatic amines. However, as amidotrizoate is an aromatic carboxylate, this is added via the decarboxylation reaction. The investigation did not reveal toxicity except for the lower current density used, which has shown a modest toxicity, most likely for some reaction intermediates that are not further degraded. In order to obtain total removal of the contrast media, it was necessary to employ a current intensity between 118 and 182 mA/cm2 with energy consumption higher than 370 kWh/m3. Overall, the electrochemical degradation was revealed to be a reliable process for the treatment of iodinated contrast media that can be found in contaminated waters such as hospital wastewater or pharmaceutical waste-contaminated streams. - Highlights: • The electrochemical degradation of six iodinated contrast media were investigated. • Treatment feasibility as well as reaction by-products and toxicity were investigated. • In all the investigated cases, the removal efficiency was higher than 80%. • Two main degradation pathways were identified

  5. Iodinated contrast media electro-degradation: Process performance and degradation pathways

    Energy Technology Data Exchange (ETDEWEB)

    Del Moro, Guido; Pastore, Carlo; Di Iaconi, Claudio; Mascolo, Giuseppe, E-mail: giuseppe.mascolo@ba.irsa.cnr.it

    2015-02-15

    The electrochemical degradation of six of the most widely used iodinated contrast media was investigated. Batch experiments were performed under constant current conditions using two DSA® electrodes (titanium coated with a proprietary and patented mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum). The degradation removal never fell below 85% (at a current density of 64 mA/cm{sup 2} with a reaction time of 150 min) when perchlorate was used as the supporting electrolyte; however, when sulphate was used, the degradation performance was above 80% (at a current density of 64 mA/cm{sup 2} with a reaction time of 150 min) for all of the compounds studied. Three main degradation pathways were identified, namely, the reductive de-iodination of the aromatic ring, the reduction of alkyl aromatic amides to simple amides and the de-acylation of N-aromatic amides to produce aromatic amines. However, as amidotrizoate is an aromatic carboxylate, this is added via the decarboxylation reaction. The investigation did not reveal toxicity except for the lower current density used, which has shown a modest toxicity, most likely for some reaction intermediates that are not further degraded. In order to obtain total removal of the contrast media, it was necessary to employ a current intensity between 118 and 182 mA/cm{sup 2} with energy consumption higher than 370 kWh/m{sup 3}. Overall, the electrochemical degradation was revealed to be a reliable process for the treatment of iodinated contrast media that can be found in contaminated waters such as hospital wastewater or pharmaceutical waste-contaminated streams. - Highlights: • The electrochemical degradation of six iodinated contrast media were investigated. • Treatment feasibility as well as reaction by-products and toxicity were investigated. • In all the investigated cases, the removal efficiency was higher than 80%. • Two main degradation pathways were identified.

  6. Complementary roles of intracellular and pericellular collagen degradation pathways in vivo

    DEFF Research Database (Denmark)

    Wagenaar-Miller, Rebecca A; Engelholm, Lars H; Gavard, Julie;

    2007-01-01

    Collagen degradation is essential for cell migration, proliferation, and differentiation. Two key turnover pathways have been described for collagen: intracellular cathepsin-mediated degradation and pericellular collagenase-mediated degradation. However, the functional relationship between these ...

  7. Degradation of phenazone in aqueous solution with ozone: influencing factors and degradation pathways.

    Science.gov (United States)

    Miao, Heng-Feng; Cao, Meng; Xu, Dan-Yao; Ren, Hong-Yan; Zhao, Ming-Xing; Huang, Zhen-Xing; Ruan, Wen-Quan

    2015-01-01

    Oxidation kinetics and degradation pathways of phenazone (an analgesic and antipyretic drug) upon reaction with O3 were investigated. Kinetic studies on degradation of phenazone were carried out under different operating conditions such as temperature, pH, anions and H2O2 addition. Results showed that the degradation followed the pseudo-first-order kinetic model. The reaction rate constant (kobs) of phenazone reached the maximum at 20 °C (9.653×10(-3) s(-1)). The presence of NO3(-) could enhance the degradation rate, while the addition of HCO3(-), SO4(2)(-), Cl(-) and the rise of pH showed negative effects on the ozonation of phenazone. H2O2 addition increased the phenazone degradation efficiency by 45.9% with the optimal concentration of 0.135 mM. Reaction by-products were evaluated by UPLC-Q-TOF-MS, which allowed the identification of a total of 10 by-products. The transformation pathways of phenazone ozonation consisted mainly of electrophilic addition and substitution, pyrazole ring opening, hydroxylation, dephenylization and coupling. The toxicity of these intermediate products showed that they are expected not to be more toxic than phenazone, with the exception of P7 (aniline) and P10 (1,5-dimethyl-4-((1-methyl-2-phenylhydrazinyl)methoxy)-2-phenyl-1H-pyrazol-3(2H)-one).

  8. Research Progress on Production of 5-Hydroxymethylfurfural from Carbohydrates%碳水化合物制备5-羟甲基糠醛研究进展

    Institute of Scientific and Technical Information of China (English)

    罗家凤; 吴剑; 张钰萍; 杨松

    2012-01-01

    5-羟甲基糠醛(5-HMF)是一种基于生物质的重要平台小分子,综述了近几年从葡萄糖或者纤维素等制备5-HMF的方法及研究进展,阐述了5-HMF制备收率的影响因素.最后展望了固体酸催化葡萄糖或者纤维素制备5-HMF的发展趋势.%5-Hydroxylmethylfurfural (5-HMF) is a key intermediate in the biomass chemistry and petrochemical industry. The research progress on the conversion of cellulose or glucose to 5-HMF is reviewed, and the effects of different parameters are also discussed. Finally, the development tendency of solid acid catalyzed production of 5-hydroxymethylfurfural is proposed.

  9. 5-Hydroxymethylfurfural modified rhodamine B dual-function derivative: Highly sensitive and selective optical detection of pH and Cu2+

    Science.gov (United States)

    Wang, Enze; Zhou, Yanmei; Huang, Qi; Pang, Lanfang; Qiao, Han; Yu, Fang; Gao, Bin; Zhang, Junli; Min, Yinghao; Ma, Tongsen

    2016-01-01

    A dual-function optical chemosensor (RBF) was designed and easily synthesized by condensation reaction of 5-Hydroxymethylfurfural and rhodamine B hydrazide. RBF exhibited highly sensitive, highly selective and quick response to acidic pH. The fluorescence intensity of RBF exhibited a more than 41-fold increase within the pH range from 7.50 to 3.73 with a pKa value of 5.02, which could be successfully applied to monitor intracellular pH in living PC12 cells and HeLa cells. Additionally, the spectroscopy of UV-Vis and EDTA-adding experiments indicated that RBF was a highly selective and reversible colorimetric chemosensor for Cu2+ in Tris-HCl (10 mM, pH = 7.2) aqueous buffer solution as well as other metal ions had no obvious interference. Moreover, RBF has been successfully applied to detect Cu2+ in real water samples.

  10. 5-Hydroxymethylfurfural modified rhodamine B dual-function derivative: Highly sensitive and selective optical detection of pH and Cu(2+).

    Science.gov (United States)

    Wang, Enze; Zhou, Yanmei; Huang, Qi; Pang, Lanfang; Qiao, Han; Yu, Fang; Gao, Bin; Zhang, Junli; Min, Yinghao; Ma, Tongsen

    2016-01-01

    A dual-function optical chemosensor (RBF) was designed and easily synthesized by condensation reaction of 5-Hydroxymethylfurfural and rhodamine B hydrazide. RBF exhibited highly sensitive, highly selective and quick response to acidic pH. The fluorescence intensity of RBF exhibited a more than 41-fold increase within the pH range from 7.50 to 3.73 with a pKa value of 5.02, which could be successfully applied to monitor intracellular pH in living PC12 cells and HeLa cells. Additionally, the spectroscopy of UV-Vis and EDTA-adding experiments indicated that RBF was a highly selective and reversible colorimetric chemosensor for Cu(2+) in Tris-HCl (10mM, pH=7.2) aqueous buffer solution as well as other metal ions had no obvious interference. Moreover, RBF has been successfully applied to detect Cu(2+) in real water samples. PMID:26232576

  11. Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24.

    Directory of Open Access Journals (Sweden)

    Sang-Yeop Lee

    Full Text Available Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs, including benzene, toluene, and xylene (BTX, as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX.

  12. Hydrolytic and oxidative degradation of electrospun supramolecular biomaterials: In vitro degradation pathways.

    Science.gov (United States)

    Brugmans, M C P; Sӧntjens, S H M; Cox, M A J; Nandakumar, A; Bosman, A W; Mes, T; Janssen, H M; Bouten, C V C; Baaijens, F P T; Driessen-Mol, A

    2015-11-01

    The emerging field of in situ tissue engineering (TE) of load bearing tissues places high demands on the implanted scaffolds, as these scaffolds should provide mechanical stability immediately upon implantation. The new class of synthetic supramolecular biomaterial polymers, which contain non-covalent interactions between the polymer chains, thereby forming complex 3D structures by self assembly. Here, we have aimed to map the degradation characteristics of promising (supramolecular) materials, by using a combination of in vitro tests. The selected biomaterials were all polycaprolactones (PCLs), either conventional and unmodified PCL, or PCL with supramolecular hydrogen bonding moieties (either 2-ureido-[1H]-pyrimidin-4-one or bis-urea units) incorporated into the backbone. As these materials are elastomeric, they are suitable candidates for cardiovascular TE applications. Electrospun scaffold strips of these materials were incubated with solutions containing enzymes that catalyze hydrolysis, or solutions containing oxidative species. At several time points, chemical, morphological, and mechanical properties were investigated. It was demonstrated that conventional and supramolecular PCL-based polymers respond differently to enzyme-accelerated hydrolytic or oxidative degradation, depending on the morphological and chemical composition of the material. Conventional PCL is more prone to hydrolytic enzymatic degradation as compared to the investigated supramolecular materials, while, in contrast, the latter materials are more susceptible to oxidative degradation. Given the observed degradation pathways of the examined materials, we are able to tailor degradation characteristics by combining selected PCL backbones with additional supramolecular moieties. The presented combination of in vitro test methods can be employed to screen, limit, and select biomaterials for pre-clinical in vivo studies targeted to different clinical applications. PMID:26316031

  13. Hydrolytic and oxidative degradation of electrospun supramolecular biomaterials: In vitro degradation pathways.

    Science.gov (United States)

    Brugmans, M C P; Sӧntjens, S H M; Cox, M A J; Nandakumar, A; Bosman, A W; Mes, T; Janssen, H M; Bouten, C V C; Baaijens, F P T; Driessen-Mol, A

    2015-11-01

    The emerging field of in situ tissue engineering (TE) of load bearing tissues places high demands on the implanted scaffolds, as these scaffolds should provide mechanical stability immediately upon implantation. The new class of synthetic supramolecular biomaterial polymers, which contain non-covalent interactions between the polymer chains, thereby forming complex 3D structures by self assembly. Here, we have aimed to map the degradation characteristics of promising (supramolecular) materials, by using a combination of in vitro tests. The selected biomaterials were all polycaprolactones (PCLs), either conventional and unmodified PCL, or PCL with supramolecular hydrogen bonding moieties (either 2-ureido-[1H]-pyrimidin-4-one or bis-urea units) incorporated into the backbone. As these materials are elastomeric, they are suitable candidates for cardiovascular TE applications. Electrospun scaffold strips of these materials were incubated with solutions containing enzymes that catalyze hydrolysis, or solutions containing oxidative species. At several time points, chemical, morphological, and mechanical properties were investigated. It was demonstrated that conventional and supramolecular PCL-based polymers respond differently to enzyme-accelerated hydrolytic or oxidative degradation, depending on the morphological and chemical composition of the material. Conventional PCL is more prone to hydrolytic enzymatic degradation as compared to the investigated supramolecular materials, while, in contrast, the latter materials are more susceptible to oxidative degradation. Given the observed degradation pathways of the examined materials, we are able to tailor degradation characteristics by combining selected PCL backbones with additional supramolecular moieties. The presented combination of in vitro test methods can be employed to screen, limit, and select biomaterials for pre-clinical in vivo studies targeted to different clinical applications.

  14. Iodinated contrast media electro-degradation: process performance and degradation pathways.

    Science.gov (United States)

    Del Moro, Guido; Pastore, Carlo; Di Iaconi, Claudio; Mascolo, Giuseppe

    2015-02-15

    The electrochemical degradation of six of the most widely used iodinated contrast media was investigated. Batch experiments were performed under constant current conditions using two DSA® electrodes (titanium coated with a proprietary and patented mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum). The degradation removal never fell below 85% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) when perchlorate was used as the supporting electrolyte; however, when sulphate was used, the degradation performance was above 80% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) for all of the compounds studied. Three main degradation pathways were identified, namely, the reductive de-iodination of the aromatic ring, the reduction of alkyl aromatic amides to simple amides and the de-acylation of N-aromatic amides to produce aromatic amines. However, as amidotrizoate is an aromatic carboxylate, this is added via the decarboxylation reaction. The investigation did not reveal toxicity except for the lower current density used, which has shown a modest toxicity, most likely for some reaction intermediates that are not further degraded. In order to obtain total removal of the contrast media, it was necessary to employ a current intensity between 118 and 182 mA/cm(2) with energy consumption higher than 370 kWh/m(3). Overall, the electrochemical degradation was revealed to be a reliable process for the treatment of iodinated contrast media that can be found in contaminated waters such as hospital wastewater or pharmaceutical waste-contaminated streams. PMID:25433384

  15. Characterization of a novel oxyfluorfen-degrading bacterial strain Chryseobacterium aquifrigidense and its biochemical degradation pathway.

    Science.gov (United States)

    Zhao, Huanhuan; Xu, Jun; Dong, Fengshou; Liu, Xingang; Wu, Yanbing; Wu, Xiaohu; Zheng, Yongquan

    2016-08-01

    Persistent use of the diphenyl ether herbicides oxyfluorfen may seriously increase the health risks and ecological safety problems. A newly bacterium R-21 isolated from active soil was able to degrade and utilize oxyfluorfen as the sole carbon source. R-21 was identified as Chryseobacterium aquifrigidense by morphology, physiobiochemical characteristics, and genetic analysis. Under the optimum cultural conditions (pH 6.9, temperature 33.4 °C, and inoculum size 0.2 g L(-1)), R-21 could degrade 92.1 % of oxyfluorfen at 50 mg L(-1) within 5 days. During oxyfluorfen degradation, six metabolites were detected and identified by atmospheric pressure gas chromatography coupled to quadrupole-time of flight mass spectrometry and ultra-performance liquid chromatography coupled to quadrupole-time of flight mass spectrometry, and a plausible degradation pathway was deduced. Strain R-21 is a promising potential in bioremediation of oxyfluorfen-contaminated environments. PMID:27079576

  16. Biotransformation of nitrobenzene by bacteria containing toluene degradative pathways

    Energy Technology Data Exchange (ETDEWEB)

    Haigler, B.E.; Spain, J.C. (Air Force Civil Engineering Support Agency, Tyndall AFB, FL (United States))

    1991-11-01

    Nonpolar nitroaromatic compounds have been considered resistant to attack by oxygenases because of the electron withdrawing properties of the nitro group. The authors have investigate the ability of seven bacterial strains containing toluene degradative pathways to oxidize nitrobenzene. Cultures were induced with toluene vapor prior to incubation with nitrobenzene, and products were identified by high-performance liquid chromatography and gas chromatography-mass spectrometry. Pseudomonas cepacia G4 and a strain of Pseudomonas harboring the TOL plasmid (pTN2) did not transform nitrobenzene. Cells of Pseudomonas putida F1 and Pseudomonas sp. strain JS150 converted nitrobenzene to 3-nitrocatechol. Transformation of nitrobenzene in the presence of {sup 18}O{sub 2} indicated that the reaction in JS150 involved the incorporation of both atoms of oxygen in the 3-nitrocatechol, which suggests a dioxygenase mechanism. P. putida 39/D, a mutant strain of P. putida F1, converted nitrobenzene to a compound tentatively identified as cis-1, 2-dihydroxy-3-nitrocyclohexa-3, 5-diene. This compound was rapidly converted to 3-nitrocatechol by cells of strain JS150. Cultures of Pseudomonas mendocina KR-1 converted nitrobenzene to a mixture of 3- and 4-nitrophenol (10 and 63%, respectively). Pseudomonas pickettii PKO1 converted nitrobenzene to 3- and 4-nitrocatechol via 3- and 4-nitrophenol. The nitrocatechols were slowly degraded to unidentified metabolites. Nitrobenzene did not serve as an inducer for the enzymes that catalyzed its oxidation.

  17. Tetracycline degradation by ozonation in the aqueous phase: Proposed degradation intermediates and pathway

    International Nuclear Information System (INIS)

    During the ozonation of tetracycline (TC) in aqueous media at pHs 2.2 and 7.0, the effects of pH variations, protonation and dissociation of functional groups and variation in free radical exposure were investigated to elucidate the transformation pathway. Liquid chromatography-triple quadrupole mass spectrometry detected around 15 ozonation products, and uncovered their production and subsequent degradation patterns. During ozonation at pH 2.2, the TC degradation pathway was proposed on the basis of the structure, ozonation chemistry and mass spectrometry data of TC. Ozonation of TC at the C11a-C12 and C2-C3 double bonds, aromatic ring and amino group generated products of m/z 461, 477, 509 and 416, respectively. Further ozonation at the above mentioned sites gave products of m/z 432, 480, 448, 525 and 496. The removal of TOC reached a maximum of ∼40% after 2 h of ozonation, while TC was completely removed within 4-6 min at both pHs. The low TOC removal efficiency might be due to the generation of recalcitrant products and the low ozone supply for high TC concentration. Ozonation decreased the acute toxicity of TC faster at pH 7.0 than pH 2.2, but the maximum decrease was only about 40% at both pHs after 2 h of ozonation. In this study, attempts were made to understand the correlation between the transformation products, pathway, acute toxicity and quantity of residual organics in solution. Overall, ozonation was found to be a promising process for removing TC and the products initially generated.

  18. Tetracycline degradation by ozonation in the aqueous phase: Proposed degradation intermediates and pathway

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M. Hammad; Bae, Hyokwan [Water Environment Center, Korea Institute of Science and Technology, 39-1 Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791 (Korea, Republic of); Jung, Jin-Young, E-mail: jinjung@ynu.ac.kr [Department of Environmental Engineering, Yeungnam University, 214-1 Dae-Dong, Gyeongsan-Si, Gyeongsangbuk-Do 712-749 (Korea, Republic of)

    2010-09-15

    During the ozonation of tetracycline (TC) in aqueous media at pHs 2.2 and 7.0, the effects of pH variations, protonation and dissociation of functional groups and variation in free radical exposure were investigated to elucidate the transformation pathway. Liquid chromatography-triple quadrupole mass spectrometry detected around 15 ozonation products, and uncovered their production and subsequent degradation patterns. During ozonation at pH 2.2, the TC degradation pathway was proposed on the basis of the structure, ozonation chemistry and mass spectrometry data of TC. Ozonation of TC at the C11a-C12 and C2-C3 double bonds, aromatic ring and amino group generated products of m/z 461, 477, 509 and 416, respectively. Further ozonation at the above mentioned sites gave products of m/z 432, 480, 448, 525 and 496. The removal of TOC reached a maximum of {approx}40% after 2 h of ozonation, while TC was completely removed within 4-6 min at both pHs. The low TOC removal efficiency might be due to the generation of recalcitrant products and the low ozone supply for high TC concentration. Ozonation decreased the acute toxicity of TC faster at pH 7.0 than pH 2.2, but the maximum decrease was only about 40% at both pHs after 2 h of ozonation. In this study, attempts were made to understand the correlation between the transformation products, pathway, acute toxicity and quantity of residual organics in solution. Overall, ozonation was found to be a promising process for removing TC and the products initially generated.

  19. 5-Hydroxymethylfurfural (5-HMF Production from Hexoses: Limits of Heterogeneous Catalysis in Hydrothermal Conditions and Potential of Concentrated Aqueous Organic Acids as Reactive Solvent System

    Directory of Open Access Journals (Sweden)

    Nadine Essayem

    2012-09-01

    Full Text Available 5-Hydroxymethylfurfural (5-HMF is an important bio-sourced intermediate, formed from carbohydrates such as glucose or fructose. The treatment at 150–250 °C of glucose or fructose in pure water and batch conditions, with catalytic amounts of most of the usual acid-basic solid catalysts, gave limited yields in 5-HMF, due mainly to the fast formation of soluble oligomers. Niobic acid, which possesses both Lewis and Brønsted acid sites, gave the highest 5-HMF yield, 28%, when high catalyst/glucose ratio is used. By contrast, we disclose in this work that the reaction of fructose in concentrated aqueous solutions of carboxylic acids, formic, acetic or lactic acids, used as reactive solvent media, leads to the selective dehydration of fructose in 5-HMF with yields up to 64% after 2 hours at 150 °C. This shows the potential of such solvent systems for the clean and easy production of 5-HMF from carbohydrates. The influence of adding solid catalysts to the carboxylic acid media was also reported, starting from glucose.

  20. A rapid gas chromatographic injection-port derivatization method for the tandem mass spectrometric determination of patulin and 5-hydroxymethylfurfural in fruit juices.

    Science.gov (United States)

    Marsol-Vall, Alexis; Balcells, Mercè; Eras, Jordi; Canela-Garayoa, Ramon

    2016-07-01

    A novel method consisting of injection-port derivatization coupled to gas chromatography-tandem mass spectrometry is described. The method allows the rapid assessment of 5-hydroxymethylfurfural (HMF) and patulin content in apple and pear derivatives. The chromatographic separation of the compounds was achieved in a short chromatographic run (12.2min) suitable for routine controls of these compounds in the fruit juice industry. The optimal conditions for the injection-port derivatization were at 270°C, 0.5min purge-off, and a 1:2 sample:derivatization reagent ratio (v/v). These conditions represent an important saving in terms of derivatization reagent consumption and sample preparation time. Quality parameters were assessed for the target compounds, giving LOD of 0.7 and 1.6μg/kg and LOQ of 2 and 5μg/kg for patulin and HMF, respectively. These values are below the maximum patulin concentration in food products intended for infants and young children. Repeatability (%RSD n=5) was below 12% for both compounds. In addition, the method linearity ranged between 25 and 1000μg/kg and between 5 and 192μg/kg for HMF and patulin, respectively. Finally, the method was applied to study HMF and patulin content in various fruit juice samples. PMID:27240947

  1. Separation and determination of 4-methylimidazole, 2-methylimidazole and 5-hydroxymethylfurfural in beverages by amino trap column coupled with pulsed amperometric detection.

    Science.gov (United States)

    Xu, Xian-Bing; Liu, Ding-Bo; Yu, Shu-Juan; Yu, Pei; Zhao, Zhen-Gang

    2015-02-15

    A method for simultaneous determination of 4-methylimidazole (4-MeI), 2-methylimidazole (2-MeI) and 5-hydroxymethylfurfural (HMF) in beverages was developed using solid-phase extraction (SPE) and amino trap column coupled with pulsed amperometric detection (AMTC-PAD). A single amino trap column (P/N: 046122) was first applied to separate the targeted analytes in samples after SPE pretreatment. This method demonstrated low limit of quantification (0.030mg/L for methylimidazoles and 0.300mg/L for HMF) and excellent linearity with correlation of determination (R(2)=0.999 for 2-MeI, 0.997 for 4-MeI and 0.998 for HMF). Nearly no 2-MeI was found in all soft drinks. However, 4-MeI could be detected in cola drinks and soft drinks containing caramel colour (ranging from 0.13 to 0.34mg/L), whereas HMF were only found in cola drinks (ranging from 1.07 to 4.47mg/L). Thus, AMTC-PAD technique would be a valid and inexpensive alternative to analysis of 4-MeI, 2-MeI and HMF. PMID:25236220

  2. An improved method for the determination of 5-hydroxymethylfurfural in Shenfu injection by direct analysis in real time-quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Gao, Wen; Qi, Lian-Wen; Liu, Charles C; Wang, Rui; Li, Ping; Yang, Hua

    2016-07-01

    The emergence of direct analysis in real time (DART) ion source provides the great possibility for rapid analysis of hazardous substance in drugs. DART mass spectrometry (DART-MS) enabled the conducting of a fast and non-contact analysis of various samples, including solid or liquid ones, without complex sample preparation or chromatographic separation. In this study, a modified DART-quadrupole time-of-flight mass spectrometry (DART-QTOF-MS) method was developed for identification and determination of 5-hydroxymethylfurfural (5-HMF) in Shenfu (SF) injection. The quantitative transfer of sample solution was introduced to the glass tips of DIP-it sampler at a fixed volume, which significantly increases the repeatability and accuracy of analytical results. The protonated ion of dibutyl phthalate in the atmosphere was used as the reference mass for TOF-MS recalibration during the data acquisition for constant high accuracy mass measurements. Finally, the developed DART-MS method was used to determine 5-HMF in seven batches of SF injection, and the contents of 5-HMF were not higher than 100 µg/mL. The results obtained were further confirmed by an ultra-high performance liquid chromatography combined with triple quadrupole mass spectrometer (UHPLC-QQQ-MS). The overall results demonstrated that the DART-QTOF-MS method could be applied as an alternative technique for rapid monitoring 5-HMF in herbal medicine injection. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26197974

  3. 食品中5-羟甲基糠醛的形成与控制%Formation and mitigation of 5-hydroxymethylfurfural in foods

    Institute of Scientific and Technical Information of China (English)

    裴珂晗; 欧仕益

    2016-01-01

    5-羟甲基糠醛(5-hydroxymethylfurfural,HMF)是食品热加工和贮藏过程中产生的内源性污染物,主要通过美拉德反应和己糖在酸性条件下脱水产生,其形成过程受反应底物种类、加热温度、反应体系pH、水分活度及金属离子等影响.HMF具有一定神经毒性、遗传毒性;摄入后在磺基转移酶作用下可转化为具有致癌毒性的羟甲基糠醛次硫酸,因而近年来HMF受到了国内外的广泛关注.本文综述了HMF形成的途径、影响因素和控制措施.

  4. Short-term supplementation with alpha-ketoglutaric acid and 5-hydroxymethylfurfural does not prevent the hypoxia induced decrease of exercise performance despite attenuation of oxidative stress.

    Science.gov (United States)

    Gatterer, H; Greilberger, J; Philippe, M; Faulhaber, M; Djukic, R; Burtscher, M

    2013-01-01

    Reactive oxygen species are thought to partly be responsible for the hypoxia induced performance decrease. The present study evaluated the effects of a broad based antioxidant supplementation or the combined intake of alpha-ketoglutaric acid (α-KG) and 5-hydroxymethylfurfural (5-HMF) on the performance decrease at altitude. 18 healthy, well-trained males (age: 25±3 years; height: 179±6 cm; weight: 76.4±6.8 kg) were randomly assigned in a double-blind fashion to a placebo group (PL), a α-KG and 5-HMF supplementation group (AO1) or a broad based antioxidant supplementation group (AO2). Participants performed 2 incremental exercise tests to exhaustion on a cycle ergometer; the first test under normoxia and the second under hypoxia conditions (simulated altitude, FiO2=13% ~ 4 300 m). Supplementation started 48 h before the hypoxia test. Maximal oxygen uptake, maximal power output, power output at the ventilatory and lactate threshold and the tissue oxygenation index (NIRS) were measured under both conditions. Oxidative stress markers were measured before the supplementation and after the hypoxia test. Under hypoxia conditions all performance parameters decreased in the range of 19-39% with no differences between groups. A significant change from normoxia to hypoxia (pextraction, as indicated by the tissue oxygenation index, might indicate that mitochondrial functioning was actually influenced by the supplementation. PMID:22893323

  5. Three-phase catalytic system of H2O, ionic liquid, and VOPO4-SiO2 solid acid for conversion of fructose to 5-hydroxymethylfurfural.

    Science.gov (United States)

    Tian, Chengcheng; Zhu, Xiang; Chai, Song-Hai; Wu, Zili; Binder, Andrew; Brown, Suree; Li, Lin; Luo, Huimin; Guo, Yanglong; Dai, Sheng

    2014-06-01

    Efficient transformation of biomass-derived feedstocks to chemicals and fuels remains a daunting challenge in utilizing biomass as alternatives to fossil resources. A three-phase catalytic system, consisting of an aqueous phase, a hydrophobic ionic-liquid phase, and a solid-acid catalyst phase of nanostructured vanadium phosphate and mesostructured cellular foam (VPO-MCF), is developed for efficient conversion of biomass-derived fructose to 5-hydroxymethylfurfural (HMF). HMF is a promising, versatile building block for production of value-added chemicals and transportation fuels. The essence of this three-phase system lies in enabling the isolation of the solid-acid catalyst from the aqueous phase and regulation of its local environment by using a hydrophobic ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]). This system significantly inhibits the side reactions of HMF with H2O and leads to 91 mol % selectivity to HMF at 89 % of fructose conversion. The unique three-phase catalytic system opens up an alternative avenue for making solid-acid catalyst systems with controlled and locally regulated microenvironment near catalytically active sites by using a hydrophobic ionic liquid.

  6. Mechanochemical degradation of tetrabromobisphenol A: Performance, products and pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kunlun; Huang, Jun; Zhang, Wang; Yu, Yunfei; Deng, Shubo [State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, POPs Research Center, Tsinghua University, Beijing 100084 (China); Yu, Gang, E-mail: yg-den@tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, POPs Research Center, Tsinghua University, Beijing 100084 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Fe + SiO{sub 2} shows better performance than CaO in mechanochemical destruction of TBBPA. Black-Right-Pointing-Pointer Nonhazardous inorganic carbon and soluble bromide were the final products. Black-Right-Pointing-Pointer Raman and FTIR imply the generation of inorganic carbon and removal of bromine atom. Black-Right-Pointing-Pointer Tri-BBPA, bi-BBPA, mono-BBPA, BPA were the main intermediates during ball milling. Black-Right-Pointing-Pointer The bromine was balanced and the degradation pathway was proposed. - Abstract: Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant (BFR), which has received more and more concerns due to its high lipophilicity, persistency and endocrine disrupting property in the environment. Considering the possible need for the safe disposal of TBBPA containing wastes in the future, the potential of mechanochemical (MC) destruction as a promising non-combustion technology was investigated in this study. TBBPA was co-ground with calcium oxide (CaO) or the mixture of iron powder and quartz sand (Fe + SiO{sub 2}) in a planetary ball mill at room temperature. The method of Fe + SiO{sub 2} destructed over 98% of initial TBBPA after 3 h and acquired 95% debromination rate after 5 h, which showed a better performance than the CaO method. Raman spectra and Fourier transform infrared spectroscopy (FTIR) demonstrated the generation of inorganic carbon with the disappearance of benzene ring and C-Br bond, indicating the carbonization and debromination process during mechanochemical reaction. LC-MS-MS screening showed that the intermediates of the treatment with Fe + SiO{sub 2} were tri-, bi-, mono-brominated BPA, BPA and other fragments. Finally all the intermediates were also destroyed after 5 h grinding. The bromine balance was calculated and a possible reaction pathway was proposed.

  7. Theoretical Elucidation of Glucose Dehydration to 5-Hydroxymethylfurfural Catalyzed by a SO3H-Functionalized Ionic Liquid.

    Science.gov (United States)

    Li, Jingjing; Li, Jinghua; Zhang, Dongju; Liu, Chengbu

    2015-10-22

    While the catalytic conversion of glucose to 5-hydroxymethyl furfural (HMF) catalyzed by SO3H-functioned ionic liquids (ILs) has been achieved successfully, the relevant molecular mechanism is still not understood well. Choosing 1-butyl-3-methylimidazolium chloride [C4SO3HmimCl] as a representative of SO3H-functioned IL, this work presents a density functional theory (DFT) study on the catalytic mechanism for conversion of glucose into HMF. It is found that the conversion may proceed via two potential pathways and that throughout most of elementary steps, the cation of the IL plays a substantial role, functioning as a proton shuttle to promote the reaction. The chloride anion interacts with the substrate and the acidic proton in the imidazolium ring via H-bonding, as well as provides a polar environment together with the imidazolium cation to stabilize intermediates and transition states. The calculated overall barriers of the catalytic conversion along two potential pathways are 32.9 and 31.0 kcal/mol, respectively, which are compatible with the observed catalytic performance of the IL under mild conditions (100 °C). The present results provide help for rationalizing the effective conversion of glucose to HMF catalyzed by SO3H-functionalized ILs and for designing IL catalysts used in biomass conversion chemistry. PMID:26434955

  8. Conversion of the common food constituent 5-hydroxymethylfurfural into a mutagenic and carcinogenic sulfuric acid ester in the mouse in vivo.

    Science.gov (United States)

    Monien, Bernhard H; Frank, Heinz; Seidel, Albrecht; Glatt, Hansruedi

    2009-06-01

    5-Hydroxymethylfurfural (HMF), formed by acid-catalyzed dehydration and in the Maillard reaction from reducing sugars, is found at high levels in numerous foods. It was shown to initiate colon aberrant crypt foci in rats and skin papillomas and hepatocellular adenomas in mice. HMF is inactive in in vitro genotoxicity tests using standard activating systems but is activated to a mutagen by sulfotransferases. The product, 5-sulfoxymethylfurfural (SMF), is a stronger carcinogen than HMF. SMF has not been detected in the biotransfomation experiments conducted on HMF in humans and animals in vivo up to date. Here, we report pharmacokinetic properties of HMF and SMF in FVB/N mice. Sensitive assays for the quantification of HMF and SMF by LC-MS/MS multiple reaction monitoring were devised. SMF, intravenously injected (4.4 micromol/kg body mass), showed first-order elimination kinetics in blood plasma (t(1/2) = 7.9 min). HMF, injected intravenously (793 micromol/kg body mass), demonstrated biphasic kinetics in plasma (t(1/2) = 1.7 and 28 min for the initial and terminal elimination phases, respectively); the volume of distribution of the central compartment corresponded approximately to the total body water. The maximum SMF plasma level was observed at the first sampling time, 2.5 min after HMF administration. On the basis of these kinetic data, it was estimated that between 452 and 551 ppm of the initial HMF dose was converted to SMF and reached the circulation. It is likely that additional SMF reacted with cellular structures at the site of generation and thus is ignored in this balance. Our work supports the hypothesis that HMF-related carcinogenicity may be mediated by its reactive metabolite SMF. PMID:19382817

  9. Nb2O5-γ-Al2O3 nanofibers as heterogeneous catalysts for efficient conversion of glucose to 5-hydroxymethylfurfural

    Science.gov (United States)

    Jiao, Huanfeng; Zhao, Xiaoliang; Lv, Chunxiao; Wang, Yijun; Yang, Dongjiang; Li, Zhenhuan; Yao, Xiangdong

    2016-01-01

    One-dimensional γ-Al2O3 nanofibers were modified with Nb2O5 to be used as an efficient heterogeneous catalyst to catalyze biomass into 5-hydroxymethylfurfural (5-HMF). At low Nb2O5 loading, the niobia species were well dispersed on γ-Al2O3 nanofiber through Nb–O–Al bridge bonds. The interaction between Nb2O5 precursor and γ-Al2O3 nanofiber results in the niobia species with strong Lewis acid sites and intensive Brønsted acid sites, which made 5-HMF yield from glucose to reach the maximum 55.9~59.0% over Nb2O5-γ-Al2O3 nanofiber with a loading of 0.5~1 wt% Nb2O5 at 150 °C for 4 h in dimethyl sulfoxide. However, increasing Nb2O5 loading could lead to the formation of two-dimensional polymerized niobia species, three-dimensional polymerized niobia species and crystallization, which significantly influenced the distribution and quantity of the Lewis acid sites and Brönst acid sites over Nb2O5-γ-Al2O3 nanofiber. Lewis acid site Nbδ+ played a key role on the isomerization of glucose to fructose, while Brønsted acid sites are more active for the dehydration of generated fructose to 5-HMF. In addition, the heterogeneous Nb2O5-γ-Al2O3 nanofiber catalyst with suitable ratio of Lewis acid to Brönsted sites should display an more excellent catalytic performance in the conversion of glucose to 5-HMF. PMID:27666867

  10. Nb2O5-γ-Al2O3 nanofibers as heterogeneous catalysts for efficient conversion of glucose to 5-hydroxymethylfurfural

    Science.gov (United States)

    Jiao, Huanfeng; Zhao, Xiaoliang; Lv, Chunxiao; Wang, Yijun; Yang, Dongjiang; Li, Zhenhuan; Yao, Xiangdong

    2016-09-01

    One-dimensional γ-Al2O3 nanofibers were modified with Nb2O5 to be used as an efficient heterogeneous catalyst to catalyze biomass into 5-hydroxymethylfurfural (5-HMF). At low Nb2O5 loading, the niobia species were well dispersed on γ-Al2O3 nanofiber through Nb–O–Al bridge bonds. The interaction between Nb2O5 precursor and γ-Al2O3 nanofiber results in the niobia species with strong Lewis acid sites and intensive Brønsted acid sites, which made 5-HMF yield from glucose to reach the maximum 55.9~59.0% over Nb2O5-γ-Al2O3 nanofiber with a loading of 0.5~1 wt% Nb2O5 at 150 °C for 4 h in dimethyl sulfoxide. However, increasing Nb2O5 loading could lead to the formation of two-dimensional polymerized niobia species, three-dimensional polymerized niobia species and crystallization, which significantly influenced the distribution and quantity of the Lewis acid sites and Brönst acid sites over Nb2O5-γ-Al2O3 nanofiber. Lewis acid site Nbδ+ played a key role on the isomerization of glucose to fructose, while Brønsted acid sites are more active for the dehydration of generated fructose to 5-HMF. In addition, the heterogeneous Nb2O5-γ-Al2O3 nanofiber catalyst with suitable ratio of Lewis acid to Brönsted sites should display an more excellent catalytic performance in the conversion of glucose to 5-HMF.

  11. HPLC法检测乳品中5-羟甲基糠醛和糠醛%Detection of 5-Hydroxymethylfurfural and Furfural in Dairy Products by HPLC

    Institute of Scientific and Technical Information of China (English)

    赵贞; 李翠枝; 岳虹; 万鹏; 吕海燕; 邵建波

    2015-01-01

    A method for detecting of 5-Hydroxymethylfurfural (5-HMF) and furfural in dairy products by HPLC is described. The samples were precipitated and filtered at first, then separated on a C18 column with the mobile phase (water-methanol solution), and detected with UV detector at 280 nm. The result showed that 5-HMF and furfural were completely separated. The method has good linearity relationship in the range of(0.03~100) mg/kg, and high recovery rate at (83.3~113.3)%. This method is simple, accurate and good reproducibility for detecting of 5-HMF and furfural in dairy products.%建立了乳制品中5-羟甲基糠醛和糠醛的高效液相色谱分析方法。样品用沉淀剂沉淀过滤后,以水-甲醇溶液为流动相,C18反相色谱柱分离,紫外检测器280nm检测。结果表明,5-羟甲基糠醛和糠醛可以完全分离。在0.03~100.00mg/kg范围内,该方法呈良好的线性关系,回收率为83.3%~113.3%。本方法用于乳制品中5-羟甲基糠醛和糠醛的测定,操作简单、定量准确、重复性好。

  12. Conversion of Suspected Food Carcinogen 5-Hydroxymethylfurfural by Sulfotransferases and Aldehyde Dehydrogenases in Postmitochondrial Tissue Preparations of Humans, Mice, and Rats.

    Science.gov (United States)

    Sachse, Benjamin; Meinl, Walter; Glatt, Hansruedi; Monien, Bernhard H

    2016-01-01

    The food contaminant 5-hydroxymethylfurfural (HMF) is formed by heat- and acid-catalyzed reactions from carbohydrates. More than 80% of HMF is metabolized by oxidation of the aldehyde group in mice and rats. Sulfo conjugation yields mutagenic 5-sulfoxymethylfurfural, the probable cause for the neoplastic effects observed in HMF-treated rodents. Considerable metabolic differences between species hinder assessing the tumorigenic risk associated with human dietary HMF uptake. Here, we assayed HMF turnover catalyzed by sulfotransferases or by aldehyde dehydrogenases (ALDHs) in postmitochondrial preparations from liver, kidney, colon, and lung of humans, mice, and rats. The tissues-specific clearance capacities of HMF sulfo conjugation (CL(SC)) and ALDH-catalyzed oxidation (CL(OX)) were concentrated to the liver. The hepatic clearance CL(SC) in mice (males: 487 µl/min/kg bw, females: 2520 µl/min/kg bw) and rats (males: 430 µl/min/kg bw, females: 198 µl/min/kg bw) were considerably higher than those in humans (males: 21.2 µl/min/kg bw, females: 32.2 µl/min/kg bw). The ALDH-related clearance rates CLOX in mice (males: 3400 ml/min/kg bw, females: 1410 ml/min/kg bw) were higher than those of humans (males: 436 ml/min/kg bw, females: 646 ml/min/kg bw) and rats (males: 627 ml/min/kg bw, females: 679 ml/min/kg bw). The ratio of CL(OX) to CL(SC) was lowest in female mice. This finding indicated that HMF sulfo conjugation was most substantial in the liver of female mice, a target tissue for HMF-induced neoplastic effects, and that humans may be less sensitive regarding HMF sulfo conjugation compared with the rodent models. PMID:26454887

  13. 葡萄糖脱水制备5-羟甲基糠醛的研究进展%Advances in production of 5-hydroxymethylfurfural from glucose

    Institute of Scientific and Technical Information of China (English)

    胡磊; 孙勇; 林鹿

    2011-01-01

    5-羟甲基糠醛(5-HMF)是一种重要的平台化合物,具有非常广泛的应用价值和市场前景。葡萄糖的选择性脱水是制备5-HMF的主要方法之一,也是碳水化合物降解研究中的重点和难点,现在已经受到了人们越来越广泛的重视。本文综述了近年来葡萄糖制备5-HMF的研究成果,着重介绍了5-HMF的形成机理以及制备5-HMF的催化体系与溶剂体系,并对葡萄糖制备5-HMF的研究前景进行了展望,以期为5-HMF的进一步研究提供思路和参考。%5-Hydroxymethylfurfural(5-HMF)is a kind of important platform chemical compound and possesses wide application value and market prospect.Selective dehydration of glucose is one of main synthesis methods for 5-hydroxymethylfurfural and has attracted increasingly more attention.In this paper,the recent research achievements in the dehydration of glucose for preparation of 5-HMF are summarized,including formation mechanisms,catalyst systems and solvent systems,and the future research trends of 5-HMF from dehydration of glucose are prospected.

  14. Determination of 5-Hydroxymethylfurfural in Liuweidihuang Pills by HPLC%HPLC测定六味地黄浓缩丸中5-HMF的含量

    Institute of Scientific and Technical Information of China (English)

    蔡银燕; 石婷婷; 黄巧玲

    2012-01-01

    OBJECTIVE To establish an HPLC method for the determination of 5-hydroxymethylfurfural(5-HMF) in Liuweidihuang pills. METHODS The HPLC method was performed on an Agilent Zorbax C18column(250 mm×4.6 mm, 5 urn) with 284 nm as the detection wavelength, and methanol-water(20 : 80) was used as mobile phase. The column temperature was 30 ℃, and the flow rate was 1.0 mL·min‐1. RESULTS The regression results which was based on weighted least square method showed a good linearity within the range of 0.026 2-2.62 mg·nL‐1, and the average recovery was 99.7% with R.SD of 0.57%. CONCLUSION The HPLC method was accurate, sensitive and suitable for determining the content of 5-HMF in Liuweidihuang pills.%目的 建立六味地黄浓缩丸中5-羟甲基糠醛(5-HMF)的含量测定方法.方法 采用Agilent Zorbax C18色谱柱(250 mm×4.6 mm,5 μm);流动相为甲醇-水(20∶80);流速:1.0 mL·min-1;检测波长:280 nm;柱温:30℃.结果 5-HMF在0.026 2~2.62 mg·mL-1内线性关系良好,平均回收率为99.7%,RSD为0.57%.结论 该方法简便、快速、准确度好,可有效控制该制剂中5-羟甲基糠醛含量.

  15. HPLC determination of 5-hydroxymethylfurfural in Shengqifuzheng injection and preliminary study on the generation approach of 5-hydroxymethylfurfural%HPLC法测定参芪扶正注射液中5-羟甲基糠醛的含量及其来源的初步探讨

    Institute of Scientific and Technical Information of China (English)

    刘潇潇; 杨立伟; 于江泳; 林锦锋

    2012-01-01

    目的:建立己糖降解产物5-羟甲基糠醛的含量测定方法,对参芪扶正注射液中的5-羟甲基糠醛进行测定,并对其来源进行初步探讨.方法:采用Diamonsil C18(250 mm ×4.6 mm,5μmm,)色谱柱,以乙腈-0.5%醋酸溶液(3∶97)为流动相,检测波长284 nm,流速1.0 mL·min-1,柱温30℃.结果:5-羟甲基糠醛在浓度为0.94~18.8 μg· mL-1范围内与峰面积具有良好的线性关系(r =0.9999),精密度和重复性的RSD分别为0.7%和2.2%.在模拟高温灭菌的过程中发现仅有果糖受热后转化生成5-羟甲基糠醛及其相关物质.结论:该方法操作简便,结果准确可靠,可用于参芪扶正注射液中5-羟甲基糠醛的含量测定,为进一步评价中药注射液的安全性提供参考.%Objective:To establish a method for the detenninantion of 5 - hydroxymethylfurfural in Shengqifuzheng injection. Methods;The HPLC separation was performed on a Diamonsil C18 reversed -phase column with the mobile phase of acetonitrile -0.5% acetic acid(3:97) ,and the determination wavelength was 284 run. The column temperature was kept at 30℃,and the mobile phase flow rate was 1.0mL·min-1. Results:The calibration curves showed good linear regression (r =0.9999) within 0. 94 and 18. 8 μg o mL-1. Precisions and repeatabilities of the methods were 0. 7% and 2. 2% .respectively. Otherwise,only fructose generated 5 - hydroxymethylfurfural after high -temperature sterilization. Conclusion:The method was simple,reliable and suitable for the quality control of the products, supplying helpful information to the further study on the safety evaluation of traditional Chinese medicine injection.

  16. MAPKs are essential upstream signaling pathways in proteolytic cartilage degradation--divergence in pathways leading to aggrecanase and MMP-mediated articular cartilage degradation

    DEFF Research Database (Denmark)

    Sondergaard, B-C; Schultz, N; Madsen, S H;

    2010-01-01

    Matrix metalloproteinases (MMPs) and aggrecanases are essential players in cartilage degradation. However, the signaling pathways that results in MMP and/or aggrecanase synthesis and activation are not well understood. We investigated the molecular events leading to MMP- and aggrecanase-mediated ...

  17. ORGANOPHOSPHORUS PESTICIDE DEGRADATION PATHWAYS DURING DRINKING WATER TREATMENT

    Science.gov (United States)

    The objective of this work was to investigate organophosphorus (OP) pesticide transformation pathways as a class in the presence of aqueous chlorine. Seven priority OP pesticides were examined for their reactivity with aqueous chlorine: chlorpyrifos (CP), parathion (PA), diazino...

  18. 3'-5' RNA degradation pathways in human cells

    DEFF Research Database (Denmark)

    Lubas, Michal Szymon

    revealed the interaction network of the main 3'-5' RNA degradation machinery – the RNA exosome complex. One of the key findings was the identification and characterisation of the Nuclear Exosome Targeting (NEXT) complex, important for nuclear functions of the exosome. Michal Lubas also studied the role...

  19. Enzymatic description of the anhydrofructose pathway of glycogen degradation. I

    DEFF Research Database (Denmark)

    Yu, Shukun; Refdahl, Charlotte; Lundt, Inge

    2004-01-01

    algae in our laboratory earlier. In the present study, two 1,5AnFru metabolizing enzymes were discovered in the fungus Anthracobia melaloma for the formation of ascopyrone P (APP), a fungal secondary metabolite exhibiting antibacterial and antioxidant activity. These are 1,5AnFru dehydratase (AFDH...... possessed all enzymes needed for conversion of glycogen to APP, an a-1,4-glucan lyase from this fungus was isolated and partially sequenced. Based on this work, a scheme of the enzymatic description of the anhydrofructose pathway in A. melaloma was proposed. Keywords: Anhydrofructose pathway; Anthracobia...

  20. PHOSPHOLIPIDS OF FIVE PSEUDOMONAD ARCHETYPES FOR DIFFERENT TOLUENE DEGRADATION PATHWAYS

    Science.gov (United States)

    Liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was used to determine phospholipid profiles for five reference pseudomonad strains harboring distinct toluene catabolic pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, B...

  1. Aerobic Degradation of Dinitrotoluenes and Pathway for Bacterial Degradation of 2,6-Dinitrotoluene

    OpenAIRE

    Nishino, Shirley F.; Paoli, George C.; Spain, Jim C.

    2000-01-01

    An oxidative pathway for the mineralization of 2,4-dinitrotoluene (2,4-DNT) by Burkholderia sp. strain DNT has been reported previously. We report here the isolation of additional strains with the ability to mineralize 2,4-DNT by the same pathway and the isolation and characterization of bacterial strains that mineralize 2,6-dinitrotoluene (2,6-DNT) by a different pathway. Burkholderia cepacia strain JS850 and Hydrogenophaga palleronii strain JS863 grew on 2,6-DNT as the sole source of carbon...

  2. Characterization of the novel dimethyl sulfide-degrading bacterium Alcaligenes sp. SY1 and its biochemical degradation pathway.

    Science.gov (United States)

    Sun, Yiming; Qiu, Jiguo; Chen, Dongzhi; Ye, Jiexu; Chen, Jianmeng

    2016-03-01

    Recently, the biodegradation of volatile organic sulfur compounds (VOSCs) has become a burgeoning field, with a growing focus on the reduction of VOSCs. The reduction of VOSCs encompasses both organic emission control and odor control. Herein, Alcaligenes sp. SY1 was isolated from active sludge and found to utilize dimethyl sulfide (DMS) as a growth substrate in a mineral salt medium. Response surface methodology (RSM) analysis was applied to optimize the incubation conditions. The following conditions for optimal degradation were identified: temperature 27.03°C; pH 7.80; inoculum salinity 0.84%; and initial DMS concentration 1585.39 μM. Under these conditions, approximately 99% of the DMS was degraded within 30 h of incubation. Two metabolic compounds were detected and identified by gas chromatography-mass spectrometry (GC-MS): dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS). The DMS degradation kinetics for different concentrations were evaluated using the Haldane-Andrews model and the pseudo first-order model. The maximum specific growth rate and degradation rate of Alcaligenes sp. SY1 were 0.17 h(-1) and 0.63 gs gx(-1)h(-1). A possible degradation pathway is proposed, and the results suggest that Alcaligenes sp. SY1 has the potential to control odor emissions under aerobic conditions. PMID:26623933

  3. A second pathway to degrade pyrimidine nucleic acid precursors in eukaryotes

    DEFF Research Database (Denmark)

    Andersen, Gorm; Bjornberg, Olof; Polakova, Silvia;

    2008-01-01

    Pyrimidine bases are the central precursors for RNA and DNA, and their intracellular pools are determined by de novo, salvage and catabolic pathways. In eukaryotes, degradation of uracil has been believed to proceed only via the reduction to dihydrouracil. Using a yeast model, Saccharomyces...... kluyveri, we show that during degradation, uracil is not reduced to dihydrouracil. Six loci, named URC1-6 (for uracil catabolism), are involved in the novel catabolic pathway. Four of them, URC3,5, URC6, and URC2 encode urea amidolyase, uracil phosphoribosyltransferase, and a putative transcription factor...

  4. Determination of 5-Hydroxymethylfurfural in Yangyin Qingfei Pills by HPLC%HPLC法测定养阴清肺丸中5-羟甲基糠醛的含量

    Institute of Scientific and Technical Information of China (English)

    康强; 孔令峰

    2013-01-01

    目的:建立养阴清肺丸中5-羟甲基糠醛含量的测定方法,考察不同企业养阴清肺丸中5-羟甲基糠醛的含量差异.方法:采用高效液相色谱法.色谱柱为Agilent C18 (250 mm×4.6 mm,5μm)柱,柱温为30℃,流动相为甲醇-水(10∶90),流速0.8 ml· min-1,检测波长:284 nm,进样量为10μl.结果:5-羟甲基糠醛进样量在0.020 2 ~0.404 0 μg范围内与峰面积积分值呈良好的线性关系(r=1.000 0);平均加样回收率为101.52%,RSD=2.7%(n=6).结论:该方法简便、准确、灵敏度高、重复性好,可用于养阴清肺丸中5-羟甲基糠醛的含量测定.%Objective:To establish a method for the content determination of 5-hydroxymethylfurfural in Yangyin Qingfei pills,and study the content difference in Yangyin Qingfei pills from different enterprises.Method:The determination was performed on an Agilent C18 (250 mm × 4.6 mm,5μm) column at 30℃ with the mobile phase consisted of methanol-water (10∶ 90) at the flow rate of 0.8ml · min-1.The detection wavelength was set at 284nm and the injection volume was 10 μl.Result:The linear range of 5-hydroxymethylfurfural was 0.020 2-0.404 0 μg (r =1.000 0) with the average recovery of 101.52% (RSD =2.7%,n =6).Conclusion:The method is simple,accurate,sensitive and reproducible in the content determination of 5-hydroxymethylfurfural in Yangyin Qingfei pills.

  5. Degradation of oxcarbazepine by UV-activated persulfate oxidation: kinetics, mechanisms, and pathways.

    Science.gov (United States)

    Bu, Lingjun; Zhou, Shiqing; Shi, Zhou; Deng, Lin; Li, Guangchao; Yi, Qihang; Gao, Naiyun

    2016-02-01

    The degradation kinetics and mechanism of the antiepileptic drug oxcarbazepine (OXC) by UV-activated persulfate oxidation were investigated in this study. Results showed that UV/persulfate (UV/PS) process appeared to be more effective in degrading OXC than UV or PS alone. The OXC degradation exhibited a pseudo-first order kinetics pattern and the degradation rate constants (k obs) were affected by initial OXC concentration, PS dosage, initial pH, and humic acid concentration to different degrees. It was found that low initial OXC concentration, high persulfate dosage, and initial pH enhanced the OXC degradation. Additionally, the presence of humic acid in the solution could greatly inhibit the degradation of OXC. Moreover, hydroxyl radical (OH•) and sulfate radical (SO4 (-)••) were identified to be responsible for OXC degradation and SO4 (-)• made the predominant contribution in this study. Finally, major intermediate products were identified and a preliminary degradation pathway was proposed. Results demonstrated that UV/PS system is a potential technology to control the water pollution caused by emerging contaminants such as OXC.

  6. Reconstructing metabolic pathways of hydrocarbon-degrading bacteria from the Deepwater Horizon oil spill.

    Science.gov (United States)

    Dombrowski, Nina; Donaho, John A; Gutierrez, Tony; Seitz, Kiley W; Teske, Andreas P; Baker, Brett J

    2016-01-01

    The Deepwater Horizon blowout in the Gulf of Mexico in 2010, one of the largest marine oil spills(1), changed bacterial communities in the water column and sediment as they responded to complex hydrocarbon mixtures(2-4). Shifts in community composition have been correlated to the microbial degradation and use of hydrocarbons(2,5,6), but the full genetic potential and taxon-specific metabolisms of bacterial hydrocarbon degraders remain unresolved. Here, we have reconstructed draft genomes of marine bacteria enriched from sea surface and deep plume waters of the spill that assimilate alkane and polycyclic aromatic hydrocarbons during stable-isotope probing experiments, and we identify genes of hydrocarbon degradation pathways. Alkane degradation genes were ubiquitous in the assembled genomes. Marinobacter was enriched with n-hexadecane, and uncultured Alpha- and Gammaproteobacteria populations were enriched in the polycyclic-aromatic-hydrocarbon-degrading communities and contained a broad gene set for degrading phenanthrene and naphthalene. The repertoire of polycyclic aromatic hydrocarbon use varied among different bacterial taxa and the combined capabilities of the microbial community exceeded those of its individual components, indicating that the degradation of complex hydrocarbon mixtures requires the non-redundant capabilities of a complex oil-degrading community. PMID:27572965

  7. Degradation of oxcarbazepine by UV-activated persulfate oxidation: kinetics, mechanisms, and pathways.

    Science.gov (United States)

    Bu, Lingjun; Zhou, Shiqing; Shi, Zhou; Deng, Lin; Li, Guangchao; Yi, Qihang; Gao, Naiyun

    2016-02-01

    The degradation kinetics and mechanism of the antiepileptic drug oxcarbazepine (OXC) by UV-activated persulfate oxidation were investigated in this study. Results showed that UV/persulfate (UV/PS) process appeared to be more effective in degrading OXC than UV or PS alone. The OXC degradation exhibited a pseudo-first order kinetics pattern and the degradation rate constants (k obs) were affected by initial OXC concentration, PS dosage, initial pH, and humic acid concentration to different degrees. It was found that low initial OXC concentration, high persulfate dosage, and initial pH enhanced the OXC degradation. Additionally, the presence of humic acid in the solution could greatly inhibit the degradation of OXC. Moreover, hydroxyl radical (OH•) and sulfate radical (SO4 (-)••) were identified to be responsible for OXC degradation and SO4 (-)• made the predominant contribution in this study. Finally, major intermediate products were identified and a preliminary degradation pathway was proposed. Results demonstrated that UV/PS system is a potential technology to control the water pollution caused by emerging contaminants such as OXC. PMID:26452660

  8. Tissue factor pathway inhibitor relates to fibrin degradation in patients with acute deep venous thrombosis

    DEFF Research Database (Denmark)

    Sidelmann, Johannes J; Bladbjerg, Else-Marie; Gram, Jørgen;

    2008-01-01

    Reduced concentration of tissue factor pathway inhibitor is a risk factor for development of deep venous thrombosis, whereas elevated concentrations of tissue factor pathway inhibitor are observed in patients with acute myocardial infarction and disseminated intravascular coagulation. Presently, we...... studied the association between inflammation, endothelial cell perturbation, fibrin degradation and the concentration of tissue factor pathway inhibitor in patients suspected for acute deep venous thrombosis. We determined the tissue factor pathway inhibitor -33T/C polymorphism, free and total tissue...... factor pathway inhibitor, C-reactive protein, von Willebrand factor and D-Dimer in 160 consecutive patients admitted to hospital with a tentative diagnosis of acute deep venous thrombosis. Deep venous thrombosis was identified in 57 patients (18 distal and 39 proximal). The distribution of the tissue...

  9. Nuclear mRNA degradation pathway(s are implicated in Xist regulation and X chromosome inactivation.

    Directory of Open Access Journals (Sweden)

    Constance Ciaudo

    2006-06-01

    Full Text Available A critical step in X-chromosome inactivation (XCI, which results in the dosage compensation of X-linked gene expression in mammals, is the coating of the presumptive inactive X chromosome by the large noncoding Xist RNA, which then leads to the recruitment of other factors essential for the heterochromatinisation of the inactive X and its transcriptional silencing. In an approach aimed at identifying genes implicated in the X-inactivation process by comparative transcriptional profiling of female and male mouse gastrula, we identified the Eif1 gene involved in translation initiation and RNA degradation. We show here that female embryonic stem cell lines, silenced by RNA interference for the Eif1 gene, are unable to form Xist RNA domains upon differentiation and fail to undergo X-inactivation. To probe further an effect involving RNA degradation pathways, the inhibition by RNA interference of Rent1, a factor essential for nonsense-mediated decay and Exosc10, a specific nuclear component of the exosome, was analysed and shown to similarly impair Xist upregulation and XCI. In Eif1-, Rent1-, and Exosc10-interfered clones, Xist spliced form(s are strongly downregulated, while the levels of unspliced form(s of Xist and the stability of Xist RNA remain comparable to that of the control cell lines. Our data suggests a role for mRNA nuclear degradation pathways in the critical regulation of spliced Xist mRNA levels and the onset of the X-inactivation process.

  10. Catalytic thermolysis in treating Cibacron Blue in aqueous solution: Kinetics and degradation pathway.

    Science.gov (United States)

    Su, Claire Xin-Hui; Teng, Tjoon-Tow; Wong, Yee-Shian; Morad, Norhashimah; Rafatullah, Mohd

    2016-03-01

    A thermal degradation pathway of the decolourisation of Reactive Cibacron Blue F3GA (RCB) in aqueous solution through catalytic thermolysis is established. Catalytic thermolysis is suitable for the removal of dyes from wastewater as it breaks down the complex dye molecules instead of only transferring them into another phase. RCB is a reactive dye that consists of three main groups, namely anthraquinone, benzene and triazine groups. Through catalytic thermolysis, the bonds that hold the three groups together were effectively broken and at the same time, the complex molecules degraded to form simple molecules of lower molecular weight. The degradation pathway and products were characterized and determined through UV-Vis, FT-IR and GCMS analysis. RCB dye molecule was successfully broken down into simpler molecules, namely, benzene derivatives, amines and triazine. The addition of copper sulphate, CuSO4, as a catalyst, hastens the thermal degradation of RCB by aiding in the breakdown of large, complex molecules. At pH 2 and catalyst mass loading of 5 g/L, an optimum colour removal of 66.14% was observed. The degradation rate of RCB is well explained by first order kinetics model. PMID:26741557

  11. Metagenomic identification of bacterioplankton taxa and pathways involved in microcystin degradation in lake erie.

    Directory of Open Access Journals (Sweden)

    Xiaozhen Mou

    Full Text Available Cyanobacterial harmful blooms (CyanoHABs that produce microcystins are appearing in an increasing number of freshwater ecosystems worldwide, damaging quality of water for use by human and aquatic life. Heterotrophic bacteria assemblages are thought to be important in transforming and detoxifying microcystins in natural environments. However, little is known about their taxonomic composition or pathways involved in the process. To address this knowledge gap, we compared the metagenomes of Lake Erie free-living bacterioplankton assemblages in laboratory microcosms amended with microcystins relative to unamended controls. A diverse array of bacterial phyla were responsive to elevated supply of microcystins, including Acidobacteria, Actinobacteria, Bacteroidetes, Planctomycetes, Proteobacteria of the alpha, beta, gamma, delta and epsilon subdivisions and Verrucomicrobia. At more detailed taxonomic levels, Methylophilales (mainly in genus Methylotenera and Burkholderiales (mainly in genera Bordetella, Burkholderia, Cupriavidus, Polaromonas, Ralstonia, Polynucleobacter and Variovorax of Betaproteobacteria were suggested to be more important in microcystin degradation than Sphingomonadales of Alphaproteobacteria. The latter taxa were previously thought to be major microcystin degraders. Homologs to known microcystin-degrading genes (mlr were not overrepresented in microcystin-amended metagenomes, indicating that Lake Erie bacterioplankton might employ alternative genes and/or pathways in microcystin degradation. Genes for xenobiotic metabolism were overrepresented in microcystin-amended microcosms, suggesting they are important in bacterial degradation of microcystin, a phenomenon that has been identified previously only in eukaryotic systems.

  12. Degradation kinetics and pathways of three calcium channel blockers under UV irradiation.

    Science.gov (United States)

    Zhu, Bing; Zonja, Bozo; Gonzalez, Oscar; Sans, Carme; Pérez, Sandra; Barceló, Damia; Esplugas, Santiago; Xu, Ke; Qiang, Zhimin

    2015-12-01

    Calcium channel blockers (CCBs) are a group of pharmaceuticals widely prescribed to lower blood pressure and treat heart diseases. They have been frequently detected in wastewater treatment plant (WWTP) effluents and downstream river waters, thus inducing a potential risk to aquatic ecosystems. However, little is known about the behavior and fate of CCBs under UV irradiation, which has been adopted as a primary disinfection method for WWTP effluents. This study investigated the degradation kinetics and pathways of three commonly-used CCBs, including amlodipine (AML), diltiazem (DIL), and verapamil (VER), under UV (254 nm) irradiation. The chemical structures of transformation byproducts (TBPs) were first identified to assess the potential ecological hazards. On that basis, a generic solid-phase extraction method, which simultaneously used four different cartridges, was adopted to extract and enrich the TBPs. Thereafter, the photo-degradation of target CCBs was performed under UV fluences typical for WWTP effluent disinfection. The degradation of all three CCBs conformed to the pseudo-first-order kinetics, with rate constants of 0.031, 0.044 and 0.011 min(-1) for AML, DIL and VER, respectively. By comparing the MS(2) fragments and the evolution (i.e., formation or decay) trends of identified TBPs, the degradation pathways were proposed. In the WWTP effluent, although the target CCBs could be degraded, several TBPs still contained the functional pharmacophores and reached peak concentrations under UV fluences of 40-100 mJ cm(-2).

  13. Degradation of ibuprofen by hydrodynamic cavitation: Reaction pathways and effect of operational parameters.

    Science.gov (United States)

    Musmarra, Dino; Prisciandaro, Marina; Capocelli, Mauro; Karatza, Despina; Iovino, Pasquale; Canzano, Silvana; Lancia, Amedeo

    2016-03-01

    Ibuprofen (IBP) is an anti-inflammatory drug whose residues can be found worldwide in natural water bodies resulting in harmful effects to aquatic species even at low concentrations. This paper deals with the degradation of IBP in water by hydrodynamic cavitation in a convergent-divergent nozzle. Over 60% of ibuprofen was degraded in 60 min with an electrical energy per order (EEO) of 10.77 kWh m(-3) at an initial concentration of 200 μg L(-1) and a relative inlet pressure pin=0.35 MPa. Five intermediates generated from different hydroxylation reactions were identified; the potential mechanisms of degradation were sketched and discussed. The reaction pathways recognized are in line with the relevant literature, both experimental and theoretical. By varying the pressure upstream the constriction, different degradation rates were observed. This effect was discussed according to a numerical simulation of the hydroxyl radical production identifying a clear correspondence between the maximum kinetic constant kOH and the maximum calculated OH production. Furthermore, in the investigated experimental conditions, the pH parameter was found not to affect the extent of degradation; this peculiar feature agrees with a recently published kinetic insight and has been explained in the light of the intermediates of the different reaction pathways.

  14. Combination of degradation pathways for naphthalene utilization in Rhodococcus sp. strain TFB.

    Science.gov (United States)

    Tomás-Gallardo, Laura; Gómez-Álvarez, Helena; Santero, Eduardo; Floriano, Belén

    2014-03-01

    Rhodococcus sp. strain TFB is a metabolic versatile bacterium able to grow on naphthalene as the only carbon and energy source. Applying proteomic, genetic and biochemical approaches, we propose in this paper that, at least, three coordinated but independently regulated set of genes are combined to degrade naphthalene in TFB. First, proteins involved in tetralin degradation are also induced by naphthalene and may carry out its conversion to salicylaldehyde. This is the only part of the naphthalene degradation pathway showing glucose catabolite repression. Second, a salicylaldehyde dehydrogenase activity that converts salicylaldehyde to salicylate is detected in naphthalene-grown cells but not in tetralin- or salicylate-grown cells. Finally, we describe the chromosomally located nag genes, encoding the gentisate pathway for salicylate conversion into fumarate and pyruvate, which are only induced by salicylate and not by naphthalene. This work shows how biodegradation pathways in Rhodococcus sp. strain TFB could be assembled using elements from different pathways mainly because of the laxity of the regulatory systems and the broad specificity of the catabolic enzymes. PMID:24325207

  15. NIR is degraded by the anaphase-promoting complex proteasome pathway

    Directory of Open Access Journals (Sweden)

    Jeong Ho Myong

    2014-01-01

    Full Text Available Novel INHAT Repressor (NIR is a histone acetylation inhibitor that can directly bind histone complexes and the tumor suppressors p53 and p63. Because NIR is mainly localized in the nucleolus and disappears from the nucleolus upon RNase treatment, it is thought to bind RNA or ribonucleoproteins. When NIR moves to the cytoplasm, it is immediately degraded; this degradation was blocked by MG132, a proteasome inhibitor. Furthermore, the central domain of NIR specifically bound APC-CCdh1. These data show that the stability of NIR is governed by the ubiquitin/proteasome pathway.

  16. M2-like macrophages are responsible for collagen degradation through a mannose receptor-mediated pathway

    DEFF Research Database (Denmark)

    Madsen, Daniel H; Leonard, Daniel; Masedunskas, Andrius;

    2013-01-01

    routed to lysosomes for complete degradation. Collagen uptake was predominantly executed by a quantitatively minor population of M2-like macrophages, whereas more abundant Col1a1-expressing fibroblasts and Cx3cr1-expressing macrophages internalized collagen at lower levels. Genetic ablation...... of the collagen receptors mannose receptor (Mrc1) and urokinase plasminogen activator receptor-associated protein (Endo180 and Mrc2) impaired this intracellular collagen degradation pathway. This study demonstrates the importance of receptor-mediated cellular uptake to collagen turnover in vivo and identifies...

  17. 食品中糠醛和5-羟甲基糠醛的产生机理、含量检测及安全性评价研究进展%A Review on Formation Mechanism, Determination and Safety Assessment of Furfural and 5-Hydroxymethylfurfural (HMF) in Foods

    Institute of Scientific and Technical Information of China (English)

    张玉玉; 宋弋; 李全宏

    2012-01-01

    Sugar-rich foods could generate large amounts of furfural and 5-hydroxymethylfurfural during thermal processing. During these different processes, the contents of furfural and 5-hydroxymethylfurfural were also different in foods. When the contents of furfural and 5-hydroxymethylfurfural exceeded a certain limit, it would harm human health. In this paper, the mechanisms, determination methods and safety of furfural and 5-hydroxymethylfurfural have been reviewed.%含糖丰富的食品在热加工过程中会产生大量的糠醛和5-羟甲基糠醛(HMF),不同食品加工后所产生的糠醛及HMF的含量有所差异,但当含量超过标准时就会对人体产生危害。因此,本文对食品中糠醛和HMF的产生机理、含量检测分析及安全性评价进行综述。

  18. Sodium persulfate-assisted mechanochemical degradation of tetrabromobisphenol A: Efficacy, products and pathway.

    Science.gov (United States)

    Liu, Xitao; Zhang, Xiaohui; Zhang, Kunlun; Qi, Chengdu

    2016-05-01

    In recent years, activated persulfate (PS) oxidation has been developed as a new advanced oxidation process for the degradation of organic pollutants. On the other hand, the mechanochemical method has exhibited a unique advantage in dealing with chemical wastes. The degradation of tetrabromobisphenol A (TBBPA), a widely used brominated flame retardant (BFR), in wastes has attracted considerable attention. In this study, the efficacy of a CaO-mechanochemical (CaO-MC) treatment system assisted by the addition of PS for the degradation of TBBPA was investigated. Under the optimum reaction conditions with a mole ratio of PS:CaO = 1:4 and less than 12.5% of TBBPA by mass, the degradation and debromination of TBBPA were completed within 2 h, while the mineralization was completed within 4 h. Characterization of the milled sample by XRD revealed that CaSO4 crystallization occurred. The TG results illustrate that there was little organic matter left after 4 h of milling. Raman and FT-IR spectra exhibited the TBBPA destruction process and disappearance of the organic groups. Through analysis by LC/MS/MS, seventeen intermediates were identified. The mechanism of TBBPA degradation by the PS-assisted CaO-MC treatment system was explained from two aspects, the course of crystallization and the degradation of TBBPA by activated PS, and two parallel initiation pathways were proposed. PMID:26359264

  19. Degradation of 4-nitrocatechol by Burkholderia cepacia: a plasmid-encoded novel pathway.

    Science.gov (United States)

    Chauhan, A; Samanta, S K; Jain, R K

    2000-05-01

    Pseudomonas cepacia RKJ200 (now described as Burkholderia cepacia) has been shown to utilize p-nitrophenol (PNP) as sole carbon and energy source. The present work demonstrates that RKJ200 utilizes 4-nitrocatechol (NC) as the sole source of carbon, nitrogen and energy, and is degraded with concomitant release of nitrite ions. Several lines of evidence, including thin layer chromatography, gas chromatography, 1H-nuclear magnetic resonance, gas chromatography-mass spectrometry, spectral analyses and quantification of intermediates by high performance liquid chromatography, have shown that NC is degraded via 1,2, 4-benzenetriol (BT) and hydroquinone (HQ) formation. Studies carried out on a PNP- derivative and a PNP+ transconjugant also demonstrate that the genes for the NC degradative pathway reside on the plasmid present in RKJ200; the same plasmid had earlier been shown to encode genes for PNP degradation, which is also degraded via HQ formation. It is likely, therefore, that the same sets of genes encode the further metabolism of HQ in NC and PNP degradation.

  20. New metabolic pathway for degradation of 2-nitrobenzoate by Arthrobacter sp. SPG

    Science.gov (United States)

    Arora, Pankaj K.; Sharma, Ashutosh

    2015-01-01

    Arthrobacter sp. SPG utilized 2-nitrobenzoate as its sole source of carbon and energy and degraded it with accumulation of stoichiometric amounts of nitrite ions. Salicylate and catechol were detected as metabolites of the 2-nitrobenzoate degradation using high performance liquid chromatography and gas chromatography–mass spectrometry. Enzyme activities for 2-nitrobenzoate-2-monooxygenase, salicylate hydroxylase, and catechol-1,2-dioxygenase were detected in the crude extracts of the 2-nitrobenzoate-induced cells of strain SPG. The 2-nitrobenzoate-monooxygenase activity resulted in formation of salicylate and nitrite from 2-nitrobenzoate, whereas salicylate hydroxylase catalyzed the conversion of salicylate to catechol. The ring-cleaving enzyme, catechol-1,2-dioxygenase cleaved catechol to cis,cis-muconic acid. Cells of strain SPG were able to degrade 2-nitrobenzoate in sterile as well as non-sterile soil microcosms. The results of microcosm studies showed that strain SPG degraded more than 90% of 2-nitrobenzoate within 10–12 days. This study clearly shows that Arthrobacter sp. SPG degraded 2-nitrobenzoate via a new pathway with formation of salicylate and catechol as metabolites. Arthrobacter sp. SPG may be used for bioremediation of 2-nitrobenzoate-contaminated sites due to its ability to degrade 2-nitrobenzoate in soil. PMID:26082768

  1. New metabolic pathway for degradation of 2-nitrobenzoate by Arthrobacter sp. SPG

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-06-01

    Full Text Available Arthrobacter sp. SPG utilized 2-nitrobenzoate as its sole source of carbon and energy and degraded it with accumulation of stoichiometric amounts of nitrite ions. Salicylate and catechol were detected as metabolites of the 2-nitrobenzoate degradation using high performance liquid chromatography and gas chromatography-mass spectrometry. Enzyme activities for 2-nitrobenzoate-2-monooxygenase, salicylate hydroxylase, and catechol-1,2-dioxygenase were detected in the crude extracts of the 2-nitrobenzoate-induced cells of strain SPG. The 2-nitrobenzoate-monooxygenase activity resulted in formation of salicylate and nitrite from 2-nitrobenzoate whereas salicylate hydroxylase catalyzed the conversion of salicylate to catechol. The ring-cleaving enzyme, catechol-1,2-dioxygenase cleaved catechol to cis, cis-muconic acid. Cells of strain SPG were able to degrade 2-nitrobenzoate in sterile as well as non-sterile soil microcosms. The results of microcosm studies showed that strain SPG degraded more than 90% of 2-nitrobenzoate within 10-12 days. This study clearly shows that Arthrobacter sp. SPG degraded 2-nitrobenzoate via a new pathway with formation of salicylate and catechol as metabolites. Arthrobacter sp. SPG may be used for bioremediation of 2-nitrobenzoate-contaminated sites due to its ability to degrade 2-nitrobenzoate in soil.

  2. Molecular and biochemical characterization of the tetralin degradation pathway in Rhodococcus sp. strain TFB

    OpenAIRE

    Tomás‐Gallardo, Laura; Santero, Eduardo; Camafeita, Emilio; Calvo, Enrique; Schlömann, Michael; Floriano, Belén

    2009-01-01

    Summary The tetralin biodegradation pathway in Rhodococcus sp. strain TFB, a Gram‐positive bacterium resistant to genetic manipulation, was characterized using a proteomic approach. Relative protein expression in cell free extracts from tetralin‐ and glucose‐grown cells was compared using the 2D‐DIGE technique. Identification of proteins specifically expressed in tetralin‐grown cells was used to characterize a complete set of genes involved in tetralin degradation by reverse genetics. We prop...

  3. Entner-Doudoroff pathway for sulfoquinovose degradation in Pseudomonas putida SQ1.

    Science.gov (United States)

    Felux, Ann-Katrin; Spiteller, Dieter; Klebensberger, Janosch; Schleheck, David

    2015-08-01

    Sulfoquinovose (SQ; 6-deoxy-6-sulfoglucose) is the polar head group of the plant sulfolipid SQ-diacylglycerol, and SQ comprises a major proportion of the organosulfur in nature, where it is degraded by bacteria. A first degradation pathway for SQ has been demonstrated recently, a "sulfoglycolytic" pathway, in addition to the classical glycolytic (Embden-Meyerhof) pathway in Escherichia coli K-12; half of the carbon of SQ is abstracted as dihydroxyacetonephosphate (DHAP) and used for growth, whereas a C3-organosulfonate, 2,3-dihydroxypropane sulfonate (DHPS), is excreted. The environmental isolate Pseudomonas putida SQ1 is also able to use SQ for growth, and excretes a different C3-organosulfonate, 3-sulfolactate (SL). In this study, we revealed the catabolic pathway for SQ in P. putida SQ1 through differential proteomics and transcriptional analyses, by in vitro reconstitution of the complete pathway by five heterologously produced enzymes, and by identification of all four organosulfonate intermediates. The pathway follows a reaction sequence analogous to the Entner-Doudoroff pathway for glucose-6-phosphate: It involves an NAD(+)-dependent SQ dehydrogenase, 6-deoxy-6-sulfogluconolactone (SGL) lactonase, 6-deoxy-6-sulfogluconate (SG) dehydratase, and 2-keto-3,6-dideoxy-6-sulfogluconate (KDSG) aldolase. The aldolase reaction yields pyruvate, which supports growth of P. putida, and 3-sulfolactaldehyde (SLA), which is oxidized to SL by an NAD(P)(+)-dependent SLA dehydrogenase. All five enzymes are encoded in a single gene cluster that includes, for example, genes for transport and regulation. Homologous gene clusters were found in genomes of other P. putida strains, in other gamma-Proteobacteria, and in beta- and alpha-Proteobacteria, for example, in genomes of Enterobacteria, Vibrio, and Halomonas species, and in typical soil bacteria, such as Burkholderia, Herbaspirillum, and Rhizobium. PMID:26195800

  4. Thermally induced degradation pathways of three different antibody-based drug development candidates.

    Science.gov (United States)

    Fincke, Anja; Winter, Jonas; Bunte, Thomas; Olbrich, Carsten

    2014-10-01

    Protein-based medicinal products are prone to undergo a variety of chemical and physical degradation pathways. One of the most important exogenous stress condition to consider during manufacturing, transport and storage processes is temperature, because antibody-based therapeutics are only stable in a limited temperature range. In this study, three different formats of antibody-based molecules (IgG1, a bispecific scFv and a fab fragment) were exposed to thermal stress conditions occurring during transport and storage. For evaluation, an analytical platform was developed for the detection and characterization of relevant degradation pathways of different antibody-based therapeutics. The effect of thermal stress conditions on the stability of the three antibody-based formats was therefore investigated using visual inspection, different spectroscopic measurements, dynamic light scattering (DLS), differential scanning calorimetry (DSC), electrophoresis, asymmetric flow field-flow fractionation (AF4) and surface plasmon resonance technology (SPR). In summary, thermal stress led to heterogeneous chemical and physical degradation pathways of all three antibody-based formats used. In addition, identical exogenous stress conditions resulted in different kinds and levels of aggregates and fragmentation products. This knowledge is fundamental for a systematic and successful stabilization of protein-based therapeutics by the use of formulation additives.

  5. Novel degradation pathway and kinetic analysis for buprofezin removal by newly isolated Bacillus sp.

    Science.gov (United States)

    Wang, Guangli; Xu, Dayong; Xiong, Minghua; Zhang, Hui; Li, Feng; Liu, Yuan

    2016-09-15

    Given the intensive and widespread application of the pesticide, buprofezin, its environmental residues potentially pose a problem; yet little is known about buprofezin's kinetic and metabolic behaviors. In this study, a novel gram-positive strain, designated BF-5, isolated from aerobic activated sludge, was found to be capable of metabolizing buprofezin as its sole energy, carbon, and nitrogen source. Based on its physiological and biochemical characteristics, other aspects of its phenotype, and a phylogenetic analysis, strain BF-5 was identified as Bacillus sp. This study investigated the effect of culture conditions on bacterial growth and substrate degradation, such as pH, temperature, initial concentration, different nitrogen source, and additional nitrogen sources as co-substrates. The degradation rate parameters, qmax, Ks, Ki and Sm were determined to be 0.6918 h(-1), 105.4 mg L(-1), 210.5 mg L(-1), and 148.95 mg L(-1) respectively. The capture of unpublished potential metabolites by gas chromatography-mass spectrometry (GC-MS) analysis has led to the proposal of a novel degradation pathway. Taken together, our results clarify buprofezin's biodegradation pathway(s) and highlight the promising potential of strain BF-5 in bioremediation of buprofezin-contaminated environments. PMID:27208995

  6. Cadmium interferes with the degradation of ATF5 via a post-ubiquitination step of the proteasome degradation pathway

    International Nuclear Information System (INIS)

    ATF5 is a member of the CREB/ATF family of transcription factors. In the current study, using a transient transfection system to express FLAG epitope fusion proteins of ATF5, we have shown that CdCl2 or NaAsO3 increases the protein levels of ATF5 in cells, and that cadmium stabilizes the ATF5 protein. Proteasome inhibitors had a similar effect to cadmium on the cellular accumulation of ATF5. Proteasome inhibition led to an increase in ubiquitinated ATF5, while cadmium did not appear to reduce the extent of ATF5 ubiquitination. ATF5 contains a putative nuclear export signal within its N-terminus. We demonstrated that whereas deletion of N-terminal region resulted in a increase of ATF5 levels, this region does not appear to be involved in the ubiquitination of ATF5. These results indicate that ATF5 is targeted for degradation by the ubiquitin-proteasome pathway, and that cadmium slows the rate of ATF5 degradation via a post-ubiquitination mechanism.

  7. From ether to acid: A plausible degradation pathway of glycerol dialkyl glycerol tetraethers

    Science.gov (United States)

    Liu, Xiao-Lei; Birgel, Daniel; Elling, Felix J.; Sutton, Paul A.; Lipp, Julius S.; Zhu, Rong; Zhang, Chuanlun; Könneke, Martin; Peckmann, Jörn; Rowland, Steven J.; Summons, Roger E.; Hinrichs, Kai-Uwe

    2016-06-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous microbial lipids with extensive demonstrated and potential roles as paleoenvironmental proxies. Despite the great attention they receive, comparatively little is known regarding their diagenetic fate. Putative degradation products of GDGTs, identified as hydroxyl and carboxyl derivatives, were detected in lipid extracts of marine sediment, seep carbonate, hot spring sediment and cells of the marine thaumarchaeon Nitrosopumilus maritimus. The distribution of GDGT degradation products in environmental samples suggests that both biotic and abiotic processes act as sinks for GDGTs. More than a hundred newly recognized degradation products afford a view of the stepwise degradation of GDGT via (1) ether bond hydrolysis yielding hydroxyl isoprenoids, namely, GDGTol (glycerol dialkyl glycerol triether alcohol), GMGD (glycerol monobiphytanyl glycerol diether), GDD (glycerol dibiphytanol diether), GMM (glycerol monobiphytanol monoether) and bpdiol (biphytanic diol); (2) oxidation of isoprenoidal alcohols into corresponding carboxyl derivatives and (3) chain shortening to yield C39 and smaller isoprenoids. This plausible GDGT degradation pathway from glycerol ethers to isoprenoidal fatty acids provides the link to commonly detected head-to-head linked long chain isoprenoidal hydrocarbons in petroleum and sediment samples. The problematic C80 to C82 tetraacids that cause naphthenate deposits in some oil production facilities can be generated from H-shaped glycerol monoalkyl glycerol tetraethers (GMGTs) following the same process, as indicated by the distribution of related derivatives in hydrothermally influenced sediments.

  8. Carbon Nanotube Degradation in Macrophages: Live Nanoscale Monitoring and Understanding of Biological Pathway.

    Science.gov (United States)

    Elgrabli, Dan; Dachraoui, Walid; Ménard-Moyon, Cécilia; Liu, Xiao Jie; Bégin, Dominique; Bégin-Colin, Sylvie; Bianco, Alberto; Gazeau, Florence; Alloyeau, Damien

    2015-10-27

    Despite numerous applications, the cellular-clearance mechanism of multiwalled carbon nanotubes (MWCNTs) has not been clearly established yet. Previous in vitro studies showed the ability of oxidative enzymes to induce nanotube degradation. Interestingly, these enzymes have the common capacity to produce reactive oxygen species (ROS). Here, we combined material and life science approaches for revealing an intracellular way taken by macrophages to degrade carbon nanotubes. We report the in situ monitoring of ROS-mediated MWCNT degradation by liquid-cell transmission electron microscopy. Two degradation mechanisms induced by hydroxyl radicals were extracted from these unseen dynamic nanoscale investigations: a non-site-specific thinning process of the walls and a site-specific transversal drilling process on pre-existing defects of nanotubes. Remarkably, similar ROS-induced structural injuries were observed on MWCNTs after aging into macrophages from 1 to 7 days. Beside unraveling oxidative transformations of MWCNT structure, we elucidated an important, albeit not exclusive, biological pathway for MWCNT degradation in macrophages, involving NOX2 complex activation, superoxide production, and hydroxyl radical attack, which highlights the critical role of oxidative stress in cellular processing of MWCNTs.

  9. Identification of the degradation pathways of alkanolamines with TiO{sub 2} photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chung-Shin, E-mail: cslu6@ntcnc.edu.tw [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China); Chen, Chiing-Chang [Department of Science Application and Dissemination, National Taichung University, Taichung 403, Taiwan (China); Mai, Fu-Der [Department of Biochemistry, School of Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Li, Hua-Kuang [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China)

    2009-06-15

    The present study deals with the photocatalytic degradation of the alkanolamine, 2-dimethylamino-2-methyl-1-propanol (DMAMP), in the presence of TiO{sub 2} particles and UV-A ({lambda} = 365 nm) radiation. The obtained results show complete oxidation of DMAMP after 20 h, and a little over 90% of DMAMP was mineralization after 64-h of treatment. The effects of the solution pH, catalyst loading, and anions on the photocatalytic degradation of DMAMP were investigated, as well as the reaction intermediates that were formed during treatment. To the best of our knowledge, this is the first time that reports the degradation pathways of DMAMP. A number of intermediates were identified by GC/MS techniques during the treatment of DMAMP, following three tentative degradation routes. The first one is based on the oxidation of the primary alcohol group leading to the formation of corresponding aldehyde and carboxylic acid. The second route is based on the rupture of the N-C bond to form 2-methylpropanal and acetone. The last degradation route is based on the cyclization of the {beta}-amino alcohol group to form the oxazolidine derivatives.

  10. Identification of the degradation pathways of alkanolamines with TiO2 photocatalysis

    International Nuclear Information System (INIS)

    The present study deals with the photocatalytic degradation of the alkanolamine, 2-dimethylamino-2-methyl-1-propanol (DMAMP), in the presence of TiO2 particles and UV-A (λ = 365 nm) radiation. The obtained results show complete oxidation of DMAMP after 20 h, and a little over 90% of DMAMP was mineralization after 64-h of treatment. The effects of the solution pH, catalyst loading, and anions on the photocatalytic degradation of DMAMP were investigated, as well as the reaction intermediates that were formed during treatment. To the best of our knowledge, this is the first time that reports the degradation pathways of DMAMP. A number of intermediates were identified by GC/MS techniques during the treatment of DMAMP, following three tentative degradation routes. The first one is based on the oxidation of the primary alcohol group leading to the formation of corresponding aldehyde and carboxylic acid. The second route is based on the rupture of the N-C bond to form 2-methylpropanal and acetone. The last degradation route is based on the cyclization of the β-amino alcohol group to form the oxazolidine derivatives.

  11. A novel sucrose synthase pathway for sucrose degradation in cultured sycamore cells.

    Science.gov (United States)

    Huber, S C; Akazawa, T

    1986-08-01

    Enzymes of sucrose degradation and glycolysis in cultured sycamore (Acer pseudoplatanus L.) cells were assayed and characterized in crude extracts and after partial purification, in an attempt to identify pathways for sucrose catabolism. Desalted cell extracts contained similar activities (20-40 nanomoles per milligram protein per minute) of sucrose synthase, neutral invertase, glucokinase, fructokinase, phosphofructokinase, and UDPglucose pyrophosphorylase (assayed with 2 micromolar pyrophosphate (PPi). PPi-linked phosphofructokinase activity was virtually dependent upon fructose 2,6-bisphosphate, and the maximum activity exceeded that of ATP-linked phosphofructokinase. Hexokinase activity, with glucose as substrate, was highly specific for ATP, whereas fructokinase activity was relatively nonspecific. At 1 millimolar nucleoside triphosphate, fructokinase activity decreased in the order: UTP > ATP > CTP > GTP. We propose two pathways for sucrose degradation. One involves invertase action, followed by classical glycolysis of hexose sugars, and the other is a novel pathway initiated by sucrose synthase. The K(m) for sucrose of sucrose synthase was severalfold lower than that of neutral invertase (15 versus 65 millimolar), which may determine carbon partitioning between the two pathways. The sucrose synthase pathway proposed involves cycling of uridylates and PPi. UDPglucose pyrophosphorylase, which is shown to be an effective ;PPi-scavenger,' would consume PPi and form UTP. The UTP could be then utilized in the UTP-linked fructokinase reaction, thereby forming UDP for sucrose synthase. The source of PPi is postulated to arise from the back reaction of PPi-linked phosphofructokinase. Sycamore cells contained a substantial endogenous pool of PPi (about 3 nanomoles per gram fresh weight, roughly 1/10 the amount of ATP in these cells), and sufficient fructose 2,6-bisphosphate (0.09 nanomole per gram fresh weight) to activate the PPi-linked phosphofructokinase. Possible

  12. Degradation of retinoid X receptor α by TPA through proteasome pathway in gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Xiao-Feng Ye; Su Liu; Qiao Wu; Xiao-Feng Lin; Bing Zhang; Jia-Fa Wu; Ming-Qing Zhang; Wen-Jin Su

    2003-01-01

    AIM: To investigate and determine the mechanism and signal pathway of tetradecanoylphorbol-1, 3-acetate (TPA) in degradation of RXRα.METHODS: Gastric cancer cell line, BGC-823 was used in the experiments. The expression level of R XRα protein was detected by Western blot. Nuclear and cytoplasmic protein fractions were prepared through lysis of cell and centrifugation.Localization and translocation of RXRα were observed under laser-scanning confocal microscope through labeling specific anti-RXRα antibody and corresponding immunofiuorescent antibody as secondary antibody. Different inhibitors were used as required.RESULTS: In BGC-823 cells, RXRα was expressed in the nucleus. When cells were treated with TPA, expression of RXRα was repressed in a time-dependent and TPAconcentration-dependent manner. Meanwhile, translocation of RXR from the nucleus to the cytoplasm occurred, also in a time-dependent manner. When cells were pre-incubated with proteasome inhibitor MG132 for 3 hrs, followed by TPA for another 12 hrs, TPA-induced RXRα degradation was inhibited. Further observation of RXRα translocation in the presence of MG132 showed that MG-132 could block TPAinduced RXRα redistribution. Conversely, when RXRαtranslocation was inhibited by LMB, an inhibitor for blocking protein export from the nucleus, TPA could not repress expression of RXRα.CONCLUSION: TPA could induce the degradation of RXRα protein in BGC-823 cells, and this degradation is time-and TPA-concentration-dependent. Furthermore, the degradation of RXRα by TPA is via a proteasome pathway and associated with RXRα translocation from the nucleus to the cytoplasm.

  13. KCTD1 suppresses canonical Wnt signaling pathway by enhancing β-catenin degradation.

    Directory of Open Access Journals (Sweden)

    Xinxin Li

    Full Text Available The canonical Wnt signaling pathway controls normal embryonic development, cellular proliferation and growth, and its aberrant activity results in human carcinogenesis. The core component in regulation of this pathway is β-catenin, but molecular regulation mechanisms of β-catenin stability are not completely known. Here, our recent studies have shown that KCTD1 strongly inhibits TCF/LEF reporter activity. Moreover, KCTD1 interacted with β-catenin both in vivo by co-immunoprecipitation as well as in vitro through GST pull-down assays. We further mapped the interaction regions to the 1-9 armadillo repeats of β-catenin and the BTB domain of KCTD1, especially Position Ala-30 and His-33. Immunofluorescence analysis indicated that KCTD1 promotes the cytoplasmic accumulation of β-catenin. Furthermore, protein stability assays revealed that KCTD1 enhances the ubiquitination/degradation of β-catenin in a concentration-dependent manner in HeLa cells. And the degradation of β-catenin mediated by KCTD1 was alleviated by the proteasome inhibitor, MG132. In addition, KCTD1-mediated β-catenin degradation was dependent on casein kinase 1 (CK1- and glycogen synthase kinase-3β (GSK-3β-mediated phosphorylation and enhanced by the E3 ubiquitin ligase β-transducin repeat-containing protein (β-TrCP. Moreover, KCTD1 suppressed the expression of endogenous Wnt downstream genes and transcription factor AP-2α. Finally, we found that Wnt pathway member APC and tumor suppressor p53 influence KCTD1-mediated downregulation of β-catenin. These results suggest that KCTD1 functions as a novel inhibitor of Wnt signaling pathway.

  14. Preparation of 5-Hydroxymethylfurfural with Sucrose Catalyzed by In-situ Iodine%原位合成碘催化蔗糖制备5-羟甲基糠醛

    Institute of Scientific and Technical Information of China (English)

    胡宁播; 董喜恩; 罗根祥; 刘春生; 韩春玉

    2011-01-01

    着重研究以原位合成碘(即三氯化铬和碘化钠发生氧化还原反应产生的碘)为催化剂,蔗糖为原料制备羟甲基糠醛.考察了反应时间、反应温度、催化剂用量(以三氯化铬和碘化钠质量计)、蔗糖质量百分数对羟甲基糠醛收率的影响.得到以原位合成碘为催化剂的优化条件:时间45min、温度130℃、催化剂用量0.25g、蔗糖质量百分数8%.在此优化条件下,用单质碘做催化剂制备羟甲基糠醛,把两者的结果相比较.以原位合成碘为催化剂,收率达到79.5%(根据果糖部分计算);以碘为催化剂,收率达到51.1%.产物经紫外可见分光光度计检测.%The preparation of 5-hydroxymethylfurfural was studied which used in-situ iodine as catalyst (in-situ iodine was generated by redox reaction of chromium trichloride and sodium iodide) and sucrose as raw materials.The effects of reaction time, temperature, the catalyst amount, the sucrose mass percentage on the yield of 5-hydroxymethyffurfural were investigated.The most suitable condition for the reaction were as follows: the reaction time was 45 min, temperature was 130℃, the catalyst amount was 0.25g, the sucrose mass percentage was 8%.Under these conditions, the yield of 5-hydroxymethylfurfural was 79.5% and 51.1% respectively which used in-situ iodine and iodine as catalyst respectively.The products were examined with UV-Vis spectrophotometer.

  15. It's all about talking: two-way communication between proteasomal and lysosomal degradation pathways via ubiquitin.

    Science.gov (United States)

    Liebl, Martina P; Hoppe, Thorsten

    2016-08-01

    Selective degradation of proteins requires a fine-tuned coordination of the two major proteolytic pathways, the ubiquitin-proteasome system (UPS) and autophagy. Substrate selection and proteolytic activity are defined by a plethora of regulatory cofactors influencing each other. Both proteolytic pathways are initiated by ubiquitylation to mark substrate proteins for degradation, although the size and/or topology of the modification are different. In this context E3 ubiquitin ligases, ensuring the covalent attachment of activated ubiquitin to the substrate, are of special importance. The regulation of E3 ligase activity, competition between different E3 ligases for binding E2 conjugation enzymes and substrates, as well as their interplay with deubiquitylating enzymes (DUBs) represent key events in the cross talk between the UPS and autophagy. The coordination between both degradation routes is further influenced by heat shock factors and ubiquitin-binding proteins (UBPs) such as p97, p62, or optineurin. Mutations in enzymes and ubiquitin-binding proteins or a general decline of both proteolytic systems during aging result in accumulation of damaged and aggregated proteins. Thus further mechanistic understanding of how UPS and autophagy communicate might allow therapeutic intervention especially against age-related diseases. PMID:27225656

  16. Genetic immunization based on the ubiquitin-fusion degradation pathway against Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Bin [Department of Microbiology and Immunology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180 (Japan); Department of Parasitology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582 (Japan); Hiromatsu, Kenji, E-mail: khiromatsu@fukuoka-u.ac.jp [Department of Microbiology and Immunology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180 (Japan); Hisaeda, Hajime; Duan, Xuefeng; Imai, Takashi [Department of Parasitology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582 (Japan); Murata, Shigeo; Tanaka, Keiji [Department of Molecular Oncology, The Tokyo Metropolitan Institute of Medical Science, Tokyo 113-8613 (Japan); Himeno, Kunisuke [Department of Parasitology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582 (Japan)

    2010-02-12

    Cytotoxic CD8{sup +} T cells are particularly important to the development of protective immunity against the intracellular protozoan parasite, Trypanosoma cruzi, the etiological agent of Chagas disease. We have developed a new effective strategy of genetic immunization by activating CD8{sup +} T cells through the ubiquitin-fusion degradation (UFD) pathway. We constructed expression plasmids encoding the amastigote surface protein-2 (ASP-2) of T. cruzi. To induce the UFD pathway, a chimeric gene encoding ubiquitin fused to ASP-2 (pUB-ASP-2) was constructed. Mice immunized with pUB-ASP-2 presented lower parasitemia and longer survival period, compared with mice immunized with pASP-2 alone. Depletion of CD8{sup +} T cells abolished protection against T. cruzi in mice immunized with pUB-ASP-2 while depletion of CD4{sup +} T cells did not influence the effective immunity. Mice deficient in LMP2 or LMP7, subunits of immunoproteasomes, were not able to develop protective immunity induced. These results suggest that ubiquitin-fused antigens expressed in antigen-presenting cells were effectively degraded via the UFD pathway, and subsequently activated CD8{sup +} T cells. Consequently, immunization with pUB-ASP-2 was able to induce potent protective immunity against infection of T. cruzi.

  17. Genetic immunization based on the ubiquitin-fusion degradation pathway against Trypanosoma cruzi

    International Nuclear Information System (INIS)

    Cytotoxic CD8+ T cells are particularly important to the development of protective immunity against the intracellular protozoan parasite, Trypanosoma cruzi, the etiological agent of Chagas disease. We have developed a new effective strategy of genetic immunization by activating CD8+ T cells through the ubiquitin-fusion degradation (UFD) pathway. We constructed expression plasmids encoding the amastigote surface protein-2 (ASP-2) of T. cruzi. To induce the UFD pathway, a chimeric gene encoding ubiquitin fused to ASP-2 (pUB-ASP-2) was constructed. Mice immunized with pUB-ASP-2 presented lower parasitemia and longer survival period, compared with mice immunized with pASP-2 alone. Depletion of CD8+ T cells abolished protection against T. cruzi in mice immunized with pUB-ASP-2 while depletion of CD4+ T cells did not influence the effective immunity. Mice deficient in LMP2 or LMP7, subunits of immunoproteasomes, were not able to develop protective immunity induced. These results suggest that ubiquitin-fused antigens expressed in antigen-presenting cells were effectively degraded via the UFD pathway, and subsequently activated CD8+ T cells. Consequently, immunization with pUB-ASP-2 was able to induce potent protective immunity against infection of T. cruzi.

  18. Organelle interactions and possible degradation pathways visualized in high-pressure frozen algal cells.

    Science.gov (United States)

    Aichinger, N; Lütz-Meindl, U

    2005-08-01

    Summary Organelle interactions, although essential for both anabolic and catabolic pathways in plant cells have not been examined in detail so far. In the present study the structure of different organelle-organelle, organelle-vesicle and organelle-membrane interactions were investigated in growing and nongrowing cells of the green alga Micrasterias denticulata by use of high pressure freeze fixation and energy filtering transmission electron microscopy. It became clear that contacts between mitochondria always occur by formation of a cone-shaped protuberance of one of the mitochondria which penetrates into its fusion partner. In the same way, structural interactions between mitochondria and mucilage vesicles and between microbodies and mucilage vesicles are achieved. Lytic compartments contact mitochondria or mucilage vesicles again by forming protuberances and by extending their contents into the respective compartment. Detached portions of mitochondria are found inside lytic compartments as a consequence of such interactions. Mitochondria found in contact with the plasma membrane reveal structural disintegration. Our study shows that interactions of organelles and vesicles are frequent events in Micrasterias cells of different ages. The interactive contacts between lytic compartments and organelles or vesicles suggest a degradation pathway different from autophagy processes described in the literature. Both the interactions between vesicles and organelles and the degradation pathways occur independently from cytoskeleton function as demonstrated by use of cytochalasin D and the microtubule inhibitor amiprophos-methyl. PMID:16159344

  19. Chemical modification and degradation of atrazine in Medicago sativa through multiple pathways.

    Science.gov (United States)

    Zhang, Jing Jing; Lu, Yi Chen; Yang, Hong

    2014-10-01

    Atrazine is a member of the triazine herbicide family intensively used to control weeds for crop production. In this study, atrazine residues and its degraded products in alfalfa (Medicago sativa) were characterized using UPLC-TOF-MS/MS. Most of atrazine absorbed in plants was found as chemically modified derivatives like deisopropylated atrazine (DIA), dehydrogenated atrazine (DHA), or methylated atrazine (MEA), and some atrazine derivatives were conjugated through different functional groups such as sugar, glutathione, and amino acids. Interestingly, the specific conjugates DHA+hGSH (homoglutathione) and MEA-HCl+hGSH in alfalfa were detected. These results suggest that atrazine in alfalfa can be degraded through different pathways. The increased activities of glycosyltransferase and glutathione S-transferase were determined to support the atrazine degradation models. The outcome of the work uncovered the detailed mechanism for the residual atrazine accumulation and degradation in alfalfa and will help to evaluate whether the crop is suitable to be cultivated in the atrazine-polluted soil.

  20. Titanium dioxide-mediated heterogeneous photocatalytic degradation of terbufos: Parameter study and reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Wu, R.-J. [Department of Applied Chemistry, Providence University, Taichung 433, Taiwan (China); Chen, C.-C. [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China); Chen, M.-H. [Department of Applied Chemistry, Providence University, Taichung 433, Taiwan (China); Lu, C.-S. [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China)], E-mail: cslu6@ntcnc.edu.tw

    2009-03-15

    The photocatalytic degradation of terbufos in aqueous suspensions was investigated by using titanium dioxide (TiO{sub 2}) as a photocatalyst. About 99% of terbufos was degraded after UV irradiation for 90 min. Factors such as pH of the system, TiO{sub 2} dosage, and presence of anions were found to influence the degradation rate. Photodegradation of terbufos by TiO{sub 2}/UV exhibited pseudo-first-order reaction kinetics, and a reaction quantum yield of 0.289. The electrical energy consumption per order of magnitude for photocatalytic degradation of terbufos was calculated and showed that a moderated efficiency (E{sub EO} = 71 kWh/(m{sup 3} order)) was obtained in TiO{sub 2}/UV process. To obtain a better understanding of the mechanistic details of this TiO{sub 2}-assisted photodegradation of terbufos with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. The probable photodegradation pathways were proposed and discussed.

  1. Titanium dioxide-mediated heterogeneous photocatalytic degradation of terbufos: Parameter study and reaction pathways

    International Nuclear Information System (INIS)

    The photocatalytic degradation of terbufos in aqueous suspensions was investigated by using titanium dioxide (TiO2) as a photocatalyst. About 99% of terbufos was degraded after UV irradiation for 90 min. Factors such as pH of the system, TiO2 dosage, and presence of anions were found to influence the degradation rate. Photodegradation of terbufos by TiO2/UV exhibited pseudo-first-order reaction kinetics, and a reaction quantum yield of 0.289. The electrical energy consumption per order of magnitude for photocatalytic degradation of terbufos was calculated and showed that a moderated efficiency (EEO = 71 kWh/(m3 order)) was obtained in TiO2/UV process. To obtain a better understanding of the mechanistic details of this TiO2-assisted photodegradation of terbufos with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. The probable photodegradation pathways were proposed and discussed

  2. Dysfunction of two lysosome degradation pathways of α-synuclein in Parkinson's disease: potential therapeutic targets?

    Institute of Scientific and Technical Information of China (English)

    Tian-Fang Jiang; Sheng-Di Chen

    2012-01-01

    Parkinson's disease (PD) is pathologically characterized by the presence of α-synuclein (α-syn)-positive intracytoplasmic inclusions named Lewy bodies in the dopaminergic neurons of the substantia nigra.A series of morbid consequences are caused by pathologically high amounts or mutant forms of α-syn,such as defects of membrane trafficking and lipid metabolism.In this review,we consider evidence that both point mutation and overexpression of α-syn result in aberrant degradation in neurons and microglia,and this is associated with the autophagy-lysosome pathway and endosomelysosome system,leading directly to pathological intracellular aggregation,abnormal externalization and re-internalization cycling (and,in turn,internalization and re-externalization),and exocytosis.Based on these pathological changes,an increasing number of researchers have focused on these new therapeutic targets,aiming at alleviating the pathological accumulation of α-syn and re-establishing normal degradation.

  3. The non-phagocytic route of collagen uptake: a distinct degradation pathway

    DEFF Research Database (Denmark)

    Madsen, Daniel H; Ingvarsen, Signe; Jürgensen, Henrik J;

    2011-01-01

    The degradation of collagens, the most abundant proteins of the extracellular matrix, is involved in numerous physiological and pathological conditions including cancer invasion. An important turnover pathway involves cellular internalization and degradation of large, soluble collagen fragments......, generated by initial cleavage of the insoluble collagen fibers. We have previously observed that in primary mouse fibroblasts, this endocytosis of collagen fragments is dependent on the receptor urokinase plasminogen activator receptor-associated protein (uPARAP)/Endo180. Others have identified additional...... mechanisms of collagen uptake, with different associated receptors, in other cell types. These receptors include ß1-integrins, being responsible for collagen phagocytosis, and the mannose receptor. We have now utilized a newly developed monoclonal antibody against uPARAP/Endo180, which down...

  4. Tyrosol degradation via the homogentisic acid pathway in a newly isolated Halomonas strain from olive processing effluents

    OpenAIRE

    Liebgott, Pierre-Pol; Labat, Marc; Amouric, Agnès; Tholozan, Jean-Luc; LORQUIN, Jean

    2008-01-01

    To isolate a new Halomonas sp. strain capable of degrading tyrosol, a toxic compound present in olive mill wastewater, through the homogentisic acid (HGA) pathway. A moderately halophilic Gram-negative bacterium belonging to the Halomonas genus and designated strain TYRC17 was isolated from olive processing effluents. This strain was able to completely degrade tyrosol (2-(p-hydroxyphenyl)-ethanol), a toxic compound found in such effluent. Tyrosol degradation begins by an oxidation to 4-hydrox...

  5. Insulin-degrading enzyme is exported via an unconventional protein secretion pathway

    Directory of Open Access Journals (Sweden)

    Leissring Malcolm A

    2009-01-01

    Full Text Available Abstract Insulin-degrading enzyme (IDE is a ubiquitously expressed zinc-metalloprotease that degrades several pathophysiologically significant extracellular substrates, including insulin and the amyloid β-protein (Aβ, and accumulating evidence suggests that IDE dysfunction may be operative in both type 2 diabetes mellitus and Alzheimer disease (AD. Although IDE is well known to be secreted by a variety of cell types, the underlying trafficking pathway(s remain poorly understood. To address this topic, we investigated the effects of known inhibitors or stimulators of protein secretion on the secretion of IDE from murine hepatocytes and HeLa cells. IDE secretion was found to be unaffected by the classical secretion inhibitors brefeldin A (BFA, monensin, or nocodazole, treatments that readily inhibited the secretion of α1-antitrypsin (AAT overexpressed in the same cells. Using a novel cell-based Aβ-degradation assay, we show further that IDE secretion was similarly unaffected by multiple stimulators of protein secretion, including glyburide and 3'-O-(4-benzoylbenzoyl-ATP (Bz-ATP. The calcium ionophore, A23187, increased extracellular IDE activity, but only under conditions that also elicited cytotoxicity. Our results provide the first biochemical evidence that IDE export is not dependent upon the classical secretion pathway, thereby identifying IDE as a novel member of the select class of unconventionally secreted proteins. Further elucidation of the mechanisms underlying IDE secretion, which would be facilitated by the assays described herein, promises to uncover processes that might be defective in disease or manipulated for therapeutic benefit.

  6. Ubiquitin initiates sorting of Golgi and plasma membrane proteins into the vacuolar degradation pathway

    Directory of Open Access Journals (Sweden)

    Scheuring David

    2012-09-01

    Full Text Available Abstract Background In yeast and mammals, many plasma membrane (PM proteins destined for degradation are tagged with ubiquitin. These ubiquitinated proteins are internalized into clathrin-coated vesicles and are transported to early endosomal compartments. There, ubiquitinated proteins are sorted by the endosomal sorting complex required for transport (ESCRT machinery into the intraluminal vesicles of multivesicular endosomes. Degradation of these proteins occurs after endosomes fuse with lysosomes/lytic vacuoles to release their content into the lumen. In plants, some PM proteins, which cycle between the PM and endosomal compartments, have been found to be ubiquitinated, but it is unclear whether ubiquitin is sufficient to mediate internalization and thus acts as a primary sorting signal for the endocytic pathway. To test whether plants use ubiquitin as a signal for the degradation of membrane proteins, we have translationally fused ubiquitin to different fluorescent reporters for the plasma membrane and analyzed their transport. Results Ubiquitin-tagged PM reporters localized to endosomes and to the lumen of the lytic vacuole in tobacco mesophyll protoplasts and in tobacco epidermal cells. The internalization of these reporters was significantly reduced if clathrin-mediated endocytosis was inhibited by the coexpression of a mutant of the clathrin heavy chain, the clathrin hub. Surprisingly, a ubiquitin-tagged reporter for the Golgi was also transported into the lumen of the vacuole. Vacuolar delivery of the reporters was abolished upon inhibition of the ESCRT machinery, indicating that the vacuolar delivery of these reporters occurs via the endocytic transport route. Conclusions Ubiquitin acts as a sorting signal at different compartments in the endomembrane system to target membrane proteins into the vacuolar degradation pathway: If displayed at the PM, ubiquitin triggers internalization of PM reporters into the endocytic transport route

  7. Electrochemical treatment of trypan blue synthetic wastewater and its degradation pathway

    Directory of Open Access Journals (Sweden)

    ANANTHA N. SUBBA RAO

    2013-11-01

    Full Text Available The trypan blue (TB dye synthetic wastewater was treated in presence of chloride ions by electrochemical method. The effect of current density, pH, initial concentration of dye and supporting electrolyte on color and COD removal were investigated. The UV-Vis ab­sorption intensity, chemical oxygen demand (COD, cyclic voltammetry (CV, Fourier transform- infrared spectroscopy (FT-IR, gas chromatography – mass spectrometry (GC-MS analysis were conducted to investigate the kinetics and degradation pathway of TB dye.

  8. Elimination of paternal mitochondria through the lysosomal degradation pathway in C.elegans

    Institute of Scientific and Technical Information of China (English)

    Qinghua Zhou; Haimin Li; Ding Xue

    2011-01-01

    In mammals,the inheritance of mitochondrion and its DNA (mtDNA) is strictly maternal,despite the fact that a sperm can inject up to 100 functional mitochondria into the oocyte during fertilization.The mechanisms responsible for the elimination of the paternal mitochondria remain largely unknown.We report here that this paternal mitochondrial elimination process is conserved in Caenorhabditis elegans,and that the lysosomal pathway actively participates in this process.Molecular and cell biological analyses indicate that in wild-type animals paternal mitoehondria and mtDNA are destroyed within two hours after fertilization.In animals with compromised lysosomes,paternal mitochondria persist until late embryonic stages.Therefore,the lysosomal pathway plays an important role in degrading paternal mitochondria introduced into the oocyte during fertilization.Our study indicates that C.elegans is an excellent animal model for understanding and dissecting this conserved biological process critical for animal development and reproduction.

  9. 5-羟甲基糠醛在 F-55果葡糖浆贮存过程中的变化研究%Research changes of 5-hydroxymethylfurfural in F55-fructose syrup storage

    Institute of Scientific and Technical Information of China (English)

    李惠安; 伍伯良; 许永苗; 叶晓蕾; 黄智钧

    2014-01-01

    5-羟甲基糠醛(HMF)作为影响果葡糖浆风味的异味化合物之一,在贮存过程中的变化很可能直接影响到果葡糖浆制成品口感的好坏。研究了 HMF 在 F-55果葡糖浆贮存过程中的变化情况,结果表明温度升高会导致 HMF 含量在40 d 后达到最高峰。果葡糖浆在低温条件下贮存,且贮存期控制在40 d 内,可减少 HMF 对糖浆质量的影响。%5-hydroxymethylfurfural is one of the off-odor compounds that influence the flavor of high fructose syrup. Its changes in storage can influence the taste of fructose syrup. The changing situations in storage of F-55 fructose syrup were researched. Results showed when temperature raised and the storage time reached 40 days, the F-55 content increased to the peak; when temperature was controlled low and the storage time was within 40 days, the F-55 quality was less influ-enced by HMF.

  10. CrCl3催化果糖制备5-羟甲基糠醛的研究%CrCl3 Catalyzed Preparation of 5-Hydroxymethylfurfural from Fructose

    Institute of Scientific and Technical Information of China (English)

    李向阳; 郑志锋; 宁静; 郑云武

    2012-01-01

    以CrCl3 · 6H2O为催化剂,考察溶剂种类、反应温度、反应时间、催化剂用量等条件对果糖制备5-羟甲基糠醛(HMF)产率的影响.结果表明,二甲基亚砜(DMSO)是果糖制备HMF的优良溶剂;以DMSO为溶剂,当反应温度为180℃、反应时间140 min、CrCl3·6H2O催化剂用量为果糖质量5%时,果糖制备HMF的产率可达49.2%.%Taking CrCl3 · 6H2O as catalyst, the effect of the solvent type, reaction temperature, reaction time and the amount of catalyst on the yield of 5 - hydroxymethylfurfural( HMF) from fructose was studied. The results showed that dimethyl sulfoxide (DMSO) was an ideal solvent to prepare HMF with fructose. The yield of HMF could be up to 49. 2% under the conditions of using DMSO as the solvent, taking 5% of CrCl3 · 6H2O as catalyst based on the weight of fructose to react for 140 min at 180℃

  11. Determination of 5- hydroxymethylfurfural (5-HMF) in over mature vinegar by HPLC%高效液相色谱法测定老陈醋中的5-羟甲基糠醛

    Institute of Scientific and Technical Information of China (English)

    周婷婷; 杨瑞学; 宋弋; 张玉玉; 吕茜; 倪元颖; 李全宏

    2012-01-01

    利用高效液相色谱法测定老陈醋中5-羟甲基糠醛(5-HMF)的含量,以5%甲醇水溶液为流动相,采用C18色谱柱,在284nm波长条件下检测样品中的5-HMF。结果表明,该方法快速、准确,在0.0143~0.1001μg范围内线性相关系数为R2=0.9994,平均回收率88.27%~96.69%,相对标准偏差为2.09%~4.70%。%A method for the determination of 5-hydroxymethylfurfural by high-performance liquid chromatography in old mature vinegar was developed.Samples were analyzed on a Cls column at 284nm using a mixture of methanol and water(5:95, v/v)as the mobile phase.Within the linear range of 0.0143 - 0.1001μg , the method was accurate with the range of average recoveries rate and relative standard deviation of 88.27%-96.69% and 2.09% 4.70%, respectively.

  12. 离子液体中葡萄糖催化转化为5-羟甲基糠醛%Preparation of 5-hydroxymethylfurfural from glucose in ionic liquid

    Institute of Scientific and Technical Information of China (English)

    徐英钊; 漆新华; 郭海心; 李陆杨

    2011-01-01

    以绿色溶剂离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl)作为溶剂,六水合氯化铬(CrCl3.6H2O)为催化剂,研究了最重要的生物质衍生糖类葡萄糖向平台化合物5-羟甲基糠醛(HMF)的转化.该催化反应体系十分有效,在130℃下反应20min,HMF的产率可达到70%以上.并且该催化体系可以循环使用,经过5次的重复使用后仍保持稳定的活性.%An efficient process for preparation of 5-hydroxymethylfurfural ( HMF ) from glucose was developed with ionic liquid 1-butyl-3-methyl imidazolium chloride ([BMIM][Cl])as solvent and CrCl3 as catalyst. A HMF yield of above 70% could be obtained at 130 ℃ in 20 min. Recycle of the ionic liquid and CrCl3 demonstrated constant activity after 5 cycles of use.

  13. Molecular characterization of the Akt-TOR signaling pathway in rainbow trout: potential role in muscle growth/degradation

    Science.gov (United States)

    The Akt-TOR signaling pathway plays a key role in cellular metabolism and muscle growth. Hormone, nutrition and stress factors affect the Akt-TOR pathway by regulating gene transcription, protein synthesis and degradation. In addition, we previously showed that energetic demands elevate during vit...

  14. Def defines a conserved nucleolar pathway that leads p53 to proteasome-independent degradation

    Institute of Scientific and Technical Information of China (English)

    Ting Tao; Hui Shi; Yihong Guan; Delai Huang; Ye Chen; David P Lane; Jun Chen

    2013-01-01

    p53 protein turnover through the ubiquitination pathway is a vital mechanism in the regulation of its transcriptional activity; however,little is known about p53 turnover through proteasome-independent pathway(s).The digestive organ expansion factor (Def) protein is essential for the development of digestive organs.In zebrafish,loss of function of defselectively upregulates the expression of p53 response genes,which raises a question as to what is the relationship between Def and p53.We report here that Def is a nucleolar protein and that loss of function of defleads to the upregulation of p53 protein,which surprisingly accumulates in the nucleoli.Our extensive studies have demonstrated that Def can mediate the degradation of p53 protein and that this process is independent of the proteasome pathway,but dependent on the activity of Calpain3,a cysteine protease.Our findings define a novel nucleolar pathway that regulates the turnover function of p53,which will advance our understanding of p53's role in organogenesis and tumorigenesis.

  15. Kinetics and reaction pathways of formaldehyde degradation using the UV-fenton method.

    Science.gov (United States)

    Liu, Xiangxuan; Liang, Jiantao; Wang, Xuanjun

    2011-05-01

    This study was based on the purpose of investigating the reaction rules of formaldehyde (HCHO) as an intermediate product in the degradation of many other organic wastewaters. The process conditions of UV-Fenton method for the degradation of the low concentrations of HCHO were studied in a batch photochemical reactor. The results showed that, when the original HCHO concentration was 30 mg/L, at an operating temperature of 23 degrees C, pH = 3, an H202 dosage of 68 mg/L, and an H2O2-to-Fe2+ mole ratio (H2O2:Fe2+) of 5, 91.89% of the HCHO was removed after 30 minutes. The degradation of HCHO in the UV-Fenton system was basically in accordance with the exponential decay. The kinetic study results showed that the reaction orders of HCHO, Fe2+, and H2O2 in the system were 1.054, 0.510, and 0.728, respectively, and the activation energy (Ea) was 9.85 kJ/mol. The comparison of UV/H2O2, Fenton, and UV-Fenton systems for the degradation of HCHO, and the results of iron catalyst tests showed that the mechanism of UV-Fenton on the degradation of HCHO was through a synergistic effect of Fe2+ and UV light to catalyze the decomposition of H2O2. The introduction of UV irradiation to the Fenton system largely increased the degradation rate of HCHO, mainly as a result of the accelerating effect on the formation of the Fe2+/Fe3+ cycle. The reaction products were analyzed by gas chromatography-mass spectrometry and a chemical oxygen demand (COD) analyzer. The effluent gases also were analyzed by gas chromatography. Based on those results, the reaction pathways of HCHO in the UV-Fenton system were proposed. The qualitative and quantitative analysis of the reaction products and the COD showed that the main intermediate product of the reaction was formic acid, and the further oxidation of it was the rate-limiting step for the degradation of HCHO.

  16. Kinetics and pathways of ibuprofen degradation by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Xiang, Yingying; Fang, Jingyun; Shang, Chii

    2016-03-01

    The UV/chlorine advanced oxidation process (AOP), which forms reactive species such as hydroxyl radicals (HO) and reactive chlorine species (RCS) such as chlorine atoms (Cl) and Cl2(-), is being considered as an alternative to the UV/H2O2 AOP for the degradation of emerging contaminants. This study investigated the kinetics and pathways of the degradation of a recalcitrant pharmaceutical and personal care product (PPCP)-ibuprofen (IBP)-by the UV/chlorine AOP. The degradation of IBP followed the pseudo first-order kinetics. The first-order rate constant was 3.3 times higher in the UV/chlorine AOP than in the UV/H2O2 AOP for a given chemical molar dosage at pH 6. The first-order rate constant decreased from 3.1 × 10(-3) s(-1) to 5.5 × 10(-4) s(-1) with increasing pH from 6 to 9. Both HO and RCS contributed to the degradation, and the contribution of RCS increased from 22% to 30% with increasing pH from 6 to 9. The degradation was initiated by HO-induced hydroxylation and Cl-induced chlorine substitution, and sustained through decarboxylation, demethylation, chlorination and ring cleavage to form more stable products. Significant amounts of chlorinated intermediates/byproducts were formed from the UV/chlorine AOP, and four chlorinated products were newly identified. The yield of total organic chlorine (TOCl) was 31.6 μM after 90% degradation of 50 μM IBP under the experimental conditions. The known disinfection by-products (DBPs) comprised 17.4% of the TOCl. The effects of water matrix in filtered drinking water on the degradation were not significant, demonstrating the practicality of the UV/chlorine AOP for the control of some refractory PPCPs. However, the toxicity of the chlorinated products should be further assessed.

  17. Pathways and Determinants of Early Spontaneous Vegetation Succession in Degraded Lowland of South China

    Institute of Scientific and Technical Information of China (English)

    Wen-Jun Duan; Hai Ran; Sheng-Lei Fu; Qin-Feng Guo; Jun Wang

    2008-01-01

    Continuous and prolonged human disturbances have caused severe degradation of a large portion of lowland in South China, and how to restore such degraded ecosystems becomes an increasing concern. The process and mechanisms of spontaneous succession, which plays an important role in vegetation restoration, have not been adequately examined. To identify the pathways of early spontaneous vegetation succession, 41 plots representing plant communities abandoned over different times were established and Investigated. The communities and indicator species of the vegetation were classified by analyzing the important values of plant species using multivariate analyses. The reaults indicated that the plant species could be classified into nine plant communities repreaenting six succession staages. The pathway and species composition alao changed in the process of succession. We also meaeurad 13 environmental variables of microtopography, soil structure and soil nutrition in each plot to examine the driving forces of auccession and the vegetation-environment relationships. Our resulta ahowed that the environmental variables changed in diverse directions, and that aoil bulk density, soil water capacity and soU acidity were the most important factors.

  18. Aqueous photodegradation of 4-tert-butylphenol: By-products, degradation pathway and theoretical calculation assessment.

    Science.gov (United States)

    Wu, Yanlin; Shi, Jin; Chen, Hongche; Zhao, Jianfu; Dong, Wenbo

    2016-10-01

    4-tert-butylphenol (4-t-BP), an endocrine disrupting chemical, is widely distributed in natural bodies of water but is difficult to biodegrade. In this study, we focused on the transformation of 4-t-BP in photo-initiated degradation processes. The steady-state photolysis and laser flash photolysis (LFP) experiments were conducted in order to elucidate its degradation mechanism. Identification of products was performed using the GC-MS, LC-MS and theoretical calculation techniques. The oxidation pathway of 4-t-BP by hydroxyl radical (HO) was also studied and H2O2 was added to produce HO. 4-tert-butylcatechol and 4-tert-butylphenol dimer were produced in 4-t-BP direct photolysis. 4-tert-butylcatechol and hydroquinone were produced by the oxidation of HO. But the formation mechanism of 4-tert-butylcatechol in the two processes was different. The benzene ring was fractured in 4-t-BP oxidation process and 29% of TOC was degraded after 16h irradiation. PMID:27213674

  19. Paeoniflorin inhibits human glioma cells via STAT3 degradation by the ubiquitin–proteasome pathway

    Science.gov (United States)

    Nie, Xiao-hu; Ou-yang, Jia; Xing, Ying; Li, Dan-yan; Dong, Xing-yu; Liu, Ru-en; Xu, Ru-xiang

    2015-01-01

    We investigated the underlying mechanism for the potent proapoptotic effect of paeoniflorin (PF) on human glioma cells in vitro, focusing on signal transducer and activator of transcription 3 (STAT3) signaling. Significant time- and dose-dependent apoptosis and inhibition of proliferation were observed in PF-treated U87 and U251 glioma cells. Expression of STAT3, its active form phosphorylated STAT3 (p-STAT3), and several downstream molecules, including HIAP, Bcl-2, cyclin D1, and Survivin, were significantly downregulated upon PF treatment. Overexpression of STAT3 induced resistance to PF, suggesting that STAT3 was a critical target of PF. Interestingly, rapid downregulation of STAT3 was consistent with its accelerated degradation, but not with its dephosphorylation or transcriptional modulation. Using specific inhibitors, we demonstrated that the prodegradation effect of PF on STAT3 was mainly through the ubiquitin–proteasome pathway rather than via lysosomal degradation. These findings indicated that PF-induced growth suppression and apoptosis in human glioma cells through the proteasome-dependent degradation of STAT3. PMID:26508835

  20. Degradation pathway of quinolines in a biofilm system under denitrifying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, S.S.; Arvin, E.; Mosbaek, H. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Environmental Science and Engineering; Hansen, A.B. [National Environmental Research Inst., Roskilde (Denmark). Dept. of Environmental Chemistry

    1997-09-01

    This article reports for the first time the degradation pathways of quinoline, isoquinoline, and methylquinolines by a mixed culture in a biofilm under nitrate-reducing conditions. A simple reverse-phase high-performance liquid chromatography method using ultraviolet detection at 223 nm for determination of seven quinoline analogues and 15 metabolites was developed, and gas chromatography--mass spectrometry and thin-layer chromatography analyses were used for identification. The inhibition of nitrification by the parent compounds and their degradation products was assessed by a nitrification toxicity test called MINNTOX. Quinoline and 3-, 4-, 6-, and 8-methylquinoline were all transformed by hydroxylation into their 2-hydroxyquinoline analogues (2-quinolinones), and isoquinoline was transformed into 1-hydroxyisoquinoline. 2-Methylquinoline was not transformed by this microcosm, likely due to the blockage at position 2 by the methyl group. The hydroxylated metabolites of isoquinoline and quinolines methylated at the heterocyclic ring were not transformed further, whereas metabolites of quinoline and quinolines methylated at the homocyclic ring were hydrogenated at position 3 and 4, and the resulting 3,4-dihydro-2-quinolinone analogues accumulated. Of these metabolites, only 3,4-dihydro-2-quinolinone from the degradation of quinoline was further transformed into unidentified products. All quinolines and their metabolites had inhibiting effects on the nitrifying bacteria at the same level (ppm) in the applied bioassay, indicating that the inhibition of the compounds was not influenced by the initial transformation reactions.

  1. Unfolded protein response and activated degradative pathways regulation in GNE myopathy.

    Directory of Open Access Journals (Sweden)

    Honghao Li

    Full Text Available Although intracellular beta amyloid (Aβ accumulation is known as an early upstream event in the degenerative course of UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE myopathy, the process by which Aβdeposits initiate various degradative pathways, and their relationship have not been fully clarified. We studied the possible secondary responses after amyloid beta precursor protein (AβPP deposition including unfolded protein response (UPR, ubiquitin proteasome system (UPS activation and its correlation with autophagy system. Eight GNE myopathy patients and five individuals with normal muscle morphology were included in this study. We performed immunofluorescence and immunoblotting to investigate the expression of AβPP, phosphorylated tau (p-tau and endoplasmic reticulum molecular chaperones. Proteasome activities were measured by cleavage of fluorogenic substrates. The expression of proteasome subunits and linkers between proteasomal and autophagy systems were also evaluated by immunoblotting and relative quantitative real-time RT-PCR. Four molecular chaperones, glucose-regulated protein 94 (GRP94, glucose-regulated protein 78 (GRP78, calreticulin and calnexin and valosin containing protein (VCP were highly expressed in GNE myopathy. 20S proteasome subunits, three main proteasome proteolytic activities, and the factors linking UPS and autophagy system were also increased. Our study suggests that AβPP deposition results in endoplasmic reticulum stress (ERS and highly expressed VCP deliver unfolded proteins from endoplasmic reticulum to proteosomal system which is activated in endoplasmic reticulum associated degradation (ERAD in GNE myopathy. Excessive ubiquitinated unfolded proteins are exported by proteins that connect UPS and autophagy to autophagy system, which is activated as an alternative pathway for degradation.

  2. Photodegradation of gemfibrozil in aqueous solution under UV irradiation: kinetics, mechanism, toxicity, and degradation pathways.

    Science.gov (United States)

    Ma, Jingshuai; Lv, Wenying; Chen, Ping; Lu, Yida; Wang, Fengliang; Li, Fuhua; Yao, Kun; Liu, Guoguang

    2016-07-01

    The lipid regulator gemfibrozil (GEM) has been reported to be persistent in conventional wastewater treatment plants. This study investigated the photolytic behavior, toxicity of intermediate products, and degradation pathways of GEM in aqueous solutions under UV irradiation. The results demonstrated that the photodegradation of GEM followed pseudo-first-order kinetics, and the pseudo-first-order rate constant was decreased markedly with increasing initial concentrations of GEM and initial pH. The photodegradation of GEM included direct photolysis via (3)GEM(*) and self-sensitization via ROS, where the contribution rates of degradation were 0.52, 90.05, and 8.38 % for ·OH, (1)O2, and (3)GEM(*), respectively. Singlet oxygen ((1)O2) was evidenced by the molecular probe compound, furfuryl alcohol (FFA), and was identified as the primary reactive species in the photolytic process. The steady-state concentrations of (1)O2 increased from (0.324 ± 0.014) × 10(-12) to (1.021 ± 0.040) × 10(-12) mol L(-1), as the initial concentrations of GEM were increased from 5 to 20 mg L(-1). The second-order rate constant for the reaction of GEM with (1)O2 was calculated to be 2.55 × 10(6) M(-1) s(-1). The primary transformation products were identified using HPLC-MS/MS, and possible photodegradation pathways were proposed by hydroxylation, aldehydes reactions, as well as the cleavage of ether side chains. The toxicity of phototransformation product evaluation revealed that photolysis potentially provides a critical pathway for GEM toxicity reduction in potable water and wastewater treatment facilities.

  3. Stress-induced nuclear RNA degradation pathways regulate yeast bromodomain factor 2 to promote cell survival.

    Directory of Open Access Journals (Sweden)

    Kevin Roy

    2014-09-01

    Full Text Available Bromodomain proteins are key regulators of gene expression. How the levels of these factors are regulated in specific environmental conditions is unknown. Previous work has established that expression of yeast Bromodomain factor 2 (BDF2 is limited by spliceosome-mediated decay (SMD. Here we show that BDF2 is subject to an additional layer of post-transcriptional control through RNase III-mediated decay (RMD. We found that the yeast RNase III Rnt1p cleaves a stem-loop structure within the BDF2 mRNA to down-regulate its expression. However, these two nuclear RNA degradation pathways play distinct roles in the regulation of BDF2 expression, as we show that the RMD and SMD pathways of the BDF2 mRNA are differentially activated or repressed in specific environmental conditions. RMD is hyper-activated by salt stress and repressed by hydroxyurea-induced DNA damage while SMD is inactivated by salt stress and predominates during DNA damage. Mutations of cis-acting signals that control SMD and RMD rescue numerous growth defects of cells lacking Bdf1p, and show that SMD plays an important role in the DNA damage response. These results demonstrate that specific environmental conditions modulate nuclear RNA degradation pathways to control BDF2 expression and Bdf2p-mediated gene regulation. Moreover, these results show that precise dosage of Bromodomain factors is essential for cell survival in specific environmental conditions, emphasizing their importance for controlling chromatin structure and gene expression in response to environmental stress.

  4. A conserved quality-control pathway that mediates degradation of unassembled ribosomal proteins

    Science.gov (United States)

    Sung, Min-Kyung; Porras-Yakushi, Tanya R; Reitsma, Justin M; Huber, Ferdinand M; Sweredoski, Michael J; Hoelz, André; Hess, Sonja; Deshaies, Raymond J

    2016-01-01

    Overproduced yeast ribosomal protein (RP) Rpl26 fails to assemble into ribosomes and is degraded in the nucleus/nucleolus by a ubiquitin-proteasome system quality control pathway comprising the E2 enzymes Ubc4/Ubc5 and the ubiquitin ligase Tom1. tom1 cells show reduced ubiquitination of multiple RPs, exceptional accumulation of detergent-insoluble proteins including multiple RPs, and hypersensitivity to imbalances in production of RPs and rRNA, indicative of a profound perturbation to proteostasis. Tom1 directly ubiquitinates unassembled RPs primarily via residues that are concealed in mature ribosomes. Together, these data point to an important role for Tom1 in normal physiology and prompt us to refer to this pathway as ERISQ, for excess ribosomal protein quality control. A similar pathway, mediated by the Tom1 homolog Huwe1, restricts accumulation of overexpressed hRpl26 in human cells. We propose that ERISQ is a key element of the quality control machinery that sustains protein homeostasis and cellular fitness in eukaryotes. DOI: http://dx.doi.org/10.7554/eLife.19105.001 PMID:27552055

  5. Physiology of deletion mutants in the anaerobic β-myrcene degradation pathway in Castellaniella defragrans

    Directory of Open Access Journals (Sweden)

    Lüddeke Frauke

    2012-09-01

    Full Text Available Abstract Background Monoterpenes present a large and versatile group of unsaturated hydrocarbons of plant origin with widespread use in the fragrance as well as food industry. The anaerobic β-myrcene degradation pathway in Castellaniella defragrans strain 65Phen differs from well known aerobic, monooxygenase-containing pathways. The initial enzyme linalool dehydratase-isomerase ldi/LDI catalyzes the hydration of β-myrcene to (S-(+-linalool and its isomerization to geraniol. A high-affinity geraniol dehydrogenase geoA/GeDH and a geranial dehydrogenase geoB/GaDH contribute to the formation of geranic acid. A genetic system was for the first time applied for the betaproteobacterium to prove in vivo the relevance of the linalool dehydratase-isomerase and the geraniol dehydrogenase. In-frame deletion cassettes were introduced by conjugation and two homologous recombination events. Results Polar effects were absent in the in-frame deletion mutants C. defragrans Δldi and C. defragrans ΔgeoA. The physiological characterization of the strains demonstrated a requirement of the linalool dehydratase-isomerase for growth on acyclic monoterpenes, but not on cyclic monoterpenes. The deletion of geoA resulted in a phenotype with hampered growth rate on monoterpenes as sole carbon and energy source as well as reduced biomass yields. Enzyme assays revealed the presence of a second geraniol dehydrogenase. The deletion mutants were in trans complemented with the broad-host range expression vector pBBR1MCS-4ldi and pBBR1MCS-2geoA, restoring in both cases the wild type phenotype. Conclusions In-frame deletion mutants of genes in the anaerobic β-myrcene degradation revealed novel insights in the in vivo function. The deletion of a high-affinity geraniol dehydrogenase hampered, but did not preclude growth on monoterpenes. A second geraniol dehydrogenase activity was present that contributes to the β-myrcene degradation pathway. Growth on cyclic monoterpenes

  6. Degradation of the synthetic dye amaranth by the fungus Bjerkandera adusta Dec 1: inference of the degradation pathway from an analysis of decolorized products.

    Science.gov (United States)

    Gomi, Nichina; Yoshida, Shuji; Matsumoto, Kazutsugu; Okudomi, Masayuki; Konno, Hiroki; Hisabori, Toru; Sugano, Yasushi

    2011-11-01

    We examined the degradation of amaranth, a representative azo dye, by Bjerkandera adusta Dec 1. The degradation products were analyzed by high performance liquid chromatography (HPLC), visible absorbance, and electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS). At the primary culture stage (3 days), the probable reaction intermediates were 1-aminonaphthalene-2,3,6-triol, 4-(hydroxyamino) naphthalene-1-ol, and 2-hydroxy-3-[2-(4-sulfophenyl) hydrazinyl] benzenesulfonic acid. After 10 days, the reaction products detected were 4-nitrophenol, phenol, 2-hydroxy-3-nitrobenzenesulfonic acid, 4-nitrobenzene sulfonic acid, and 3,4'-disulfonyl azo benzene, suggesting that no aromatic amines were created. Manganese-dependent peroxidase activity increased sharply after 3 days culture. Based on these results, we herein propose, for the first time, a degradation pathway for amaranth. Our results suggest that Dec 1 degrades amaranth via the combined activities of peroxidase and hydrolase and reductase action.

  7. Removal and Degradation Pathways of Sulfamethoxazole Present in Synthetic Municipal Wastewater via an Anaerobic Membrane Bioreactor

    KAUST Repository

    Sanchez Huerta, Claudia

    2016-05-01

    The current global water crisis in addition to continues contamination of natural water bodies with harmful organic micropollutants (OMPs) have driven the development of new water treatment technologies that allow the efficient removal of such compounds. Among a long list of OMPs, antibiotics are considered as top priority pollutants to be treated due to their great resistance to biological treatments and their potential to develop bacterial resistance. Different approaches, such as membrane-based and advance oxidation processes have been proposed to alleviate or minimize antibiotics discharge into aquatic environments. However most of these processes are costly and generate either matrices with high concentration of OMPs or intermediate products with potentially greater toxicity or persistence. Therefore, this thesis proposes the study of an anaerobic membrane bioreactor (AnMBR) for the treatment of synthetic municipal wastewater containing sulfamethoxazole (SMX), a world widely used antibiotic. Besides the general evaluation of AnMBR performance in the COD removal and biogas production, this research mainly focuses on the SMX removal and its degradation pathway. Thus 5 SMX quantification was performed through solid phase extraction-liquid chromatography/mass spectrometry and the identification of its transformation products (TPs) was assessed by gas chromatography/mass spectrometry technique. The results achieved showed that, working under optimal conditions (35°C, pH 7 and ORP around -380 to -420 mV) and after a biomass adaptation period (maintaining 0.85 VSS/TSS ratio), the AnMBR process provided over 95% COD removal and 95-98% SMX removal, while allowing stable biogas composition and methane production (≈130 mL CH4/g CODremoved). Kinetic analysis through a batch test showed that after 24 h of biological reaction, AnMBR process achieved around 94% SMX removal, indicating a first order kinetic reaction with K= 0.119, which highlights the high degradation

  8. 磷钨酸盐催化果糖水解制备5-羟甲基糠醛%Conversion of fructose to 5-hydroxymethylfurfural catalyzed by heteropolyacid salts

    Institute of Scientific and Technical Information of China (English)

    曲永水; 黄崇品; 宋彦磊; 张傑; 陈标华

    2012-01-01

    The dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) catalyzed by a variety of heteropolyacid salts has been studied. The highest 5-HMF yield was 99. 2% , obtained using a CePW12O40 catalyst in DMSO with 5% (mass fraction) of catalyst at 160℃ with reaction time 8 h. Furthermore, the conversion of fructose to 5-HMF catalyzed by heteropolyacid salts was conducted under microwave conditions. Compared with the conventional heating method, microwave heating showed a remarkable ability to both accelerate the reaction rate and improve the yield of 5-HMF. Moreover, the catalyst could be separated from the reaction mixture by a simple process at the end of the reaction and the catalyst could be reused six times without loss of activity.%以磷钨酸盐为催化剂,研究了其对果糖水解过程的影响,考察了反应时间、温度、催化剂种类及用量等因素 对5-羟甲基糠醛(5-HMF)收率的影响.实验结果表明:160℃时在二甲基亚砜(DMSO)中,以CePW12O40为催化剂,反应8h,5-HMF的收率最高为99.2%;该催化剂循环使用6次,仍能保持较高活性,5-HMF的收率仍能保持90.5%.与传统加热方法相比,微波加热可明显加快反应速率,缩短反应时间.

  9. Catalytic conversion of glucose to 5-hydroxymethylfurfural by metal halides%金属氯化物催化葡萄糖制备5-羟甲基糠醛

    Institute of Scientific and Technical Information of China (English)

    朱萍; 范文元; 陈慧

    2015-01-01

    Using metal halides as catalyst and alkali metal halides as co-catalyst catalyzed glucose to dehydrate to make 5-hydroxymethylfurfural(5-HMF).Under the condition that the mass ratio of the material and catalyst is 10∶1 and the mass ratio of the material and co-catalyst is 1∶1,the following observations and studies were made on the influence of the metal halides、co-catalyst、solvent、temperature and time on the yield of 5-HMF.The results showed that,when NaI was used as co-catalyst for the AlCl3-catalyzed conversion of glucose at 130℃for 15 min in N,N-Dimethylacetamide (DMAC) the yield of 5-HMF is up to 30.6%.%用金属氯化物做催化剂,碱金属卤化物做助剂,催化葡萄糖脱水制备5-羟甲基糠醛(5-HMF).在原料与催化剂的质量比为10∶1,原料与助催化剂的质量比为1∶1的情况下,考察金属氯化物、助剂、溶剂、温度、时间对5-HMF收率的影响.结果显示:AlCl3做催化剂、NaI做助剂、溶剂为N,N-二甲基乙酰胺(DMAC)、反应温度为130℃、反应时间为15 min时5-HMF收率可达30.6%.

  10. Determination of 5-hydroxymethylfurfural in Zhenjiang Vinegar by HPLC%高效液相色谱法测定镇江香醋中5-羟甲基糠醛的含量

    Institute of Scientific and Technical Information of China (English)

    张玉玉; 宋弋; 周婷婷; 吕茜; 杨瑞学; 李全宏

    2012-01-01

    A method for determination of 5-hydroxymethylfurfural by high-performance liquid chromatography in Zhenjiang vinegar was developed.Samples were analyzed on a Venusil XBP-C18 column with oven temperature of 30 ℃,using a mixture of methanol and water(5∶95,v/v) as the mobile phase with the flow rate of 1.0 mL/min,and detected at 284 nm.Within the linear range of 0.014 3~0.085 8 μg,the correlation coefficient was 0.999 9.The method was accurate with the average recoveries rate and relative standard deviation of 98.66% and 5.53%,respectively.%采用高效液相色谱法,对镇江香醋中5-羟甲基糠醛进行了定量分析.样品中的HMF含量的测定条件为:以甲醇-水溶液(体积比为5∶95)为流动相,流速为1.0 mL/min,采用Venusil XBP-C18色谱柱分离,柱温为30℃,UV检测器的检测波长为284 nm.定量分析结果表明,镇江香醋中HMF的含量为8.01 mg/kg.高效液相色谱法分析镇江香醋中HMF含量的方法测定准确,稳定性高,HMF在0.014 3~0.085 8μg的进样范围内线性相关系数为R2=0.999 9,平均回收率98.66%,相对标准偏差为5.53%.

  11. Study on the Generation of 5-Hydroxymethylfurfural in Chinese Medicine Injection%中药注射液中5-羟甲基糠醛来源探讨

    Institute of Scientific and Technical Information of China (English)

    杨立伟; 刘潇潇; 李泳雪

    2012-01-01

    目的:通过对中药注射液中的5-羟甲基糠醛(5-HMF,5-Hydroxymethylfurfural)来源的初步探讨,为提高中药注射液的质量控制水平提供参考依据.方法:利用HPLC方法对注射液、中间体中的5-HMF和寡糖(葡萄糖、果糖及蔗糖)分别进行含量测定,确定5-HMF的来源;通过模拟生产过程考察不同寡糖的受热不稳定情况,来探讨5-HMF的生成机制.结果:只有在含有果糖的中间体中含有5 -HMF.模拟高温灭菌过程发现仅有果糖受热后转化生成5-羟甲基糠醛及其相关物质,而葡萄糖和蔗糖均没有转化.结论:并不是所有的寡糖在高温下都易转化5-HMF.在常见的三种糖中,只有果糖在高温下易转化生成5-HMF,而葡萄糖和蔗糖不易转化.建议对含果糖的中药注射液进行5-HMF的限度检查,而含葡萄糖和蔗糖的可以不控制该项目.

  12. 棉秆水热法制备5-羟甲基糠醛的动力学研究%Dynamics of 5-Hydroxymethylfurfural Preparation From Cotton Stalk with Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    周涛; 廖孝艳; 蒋崇文; 周礼超

    2013-01-01

    为了提高生物质中纤维素的降解率和5-羟甲基糠醛(5-hydroxymethylfurfural,5-HMF)的产率,对棉杆水热法降解生成5-HMF的过程进行了研究.通过分析各因素对纤维素降解和5-HMF合成的影响,确定最佳操作工艺条件;在催化剂SO42-/ZrO2存在与不存在时,对棉秆水热法制备5-HMF的过程进行了动力学分析.研究结果表明,催化剂SO42-/ZrO2添加质量分数为20%,在230℃下反应90 min时,纤维素降解率可达94.43%,5-HMF产率可达25.3%,相同条件下较无催化剂可提高79.4%.动力学研究表明催化剂SO42-/ZrO2对纤维素降解和5-HMF合成都具有正向催化效果.加入催化剂后,纤维素降解反应活化能由106.0 kJ·mol-1降低至96.7 kJ·mol-1,5-HMF合成反应活化能由119.4 kJ·mol-1降低至84.2 kJ·mol-1.

  13. Advances in Selective Hydrogenation of 5-Hydroxymethylfurfural into 2,5-Dimethylfuran%5-羟甲基糠醛选择性加氢制备2,5-二甲基呋喃的研究进展

    Institute of Scientific and Technical Information of China (English)

    胡磊; 吴真; 许家兴; 孙勇; 林鹿; 徐宁; 戴本林

    2015-01-01

    The renewable liquid fuel,2,5-dimethylfuran (DMF),which can be produced by the selective hydrogenation of 5-hydroxymethylfurfural ( HMF ) with high energy density, high boiling point, high octane number, and water insolubility, has attracted more attention all over the world. According to its excellent physicochemical properties, the momentous application values, and the broad market prospects, the various catalytic systems and the latest research progress for the selective hydrogenation of HMF into DMF from the point of the diversity of hydrogen donors such as molecular hydrogen, formic acid, alcohols,and water are systematically summarized. The future research trends are prospected to offer the valuable ideas and advices for the selective hydrogenation of HMF and provide the theoretical references and technical supports for the industrial production and practical application of DMF.%鉴于2,5-二甲基呋喃(DMF)优良的理化性质、重要的应用价值和广阔的市场前景,着重从氢气、甲酸、醇类和水等不同氢供体的角度入手,系统归纳和总结了自2007年以来5-羟甲基糠醛(HMF)选择性加氢制备DMF 的催化反应体系及其最新的研究进展,并对今后HMF 选择性加氢制备DMF 的研究前景进行了展望。

  14. Catalytic Dehydration of Fructose to 5-hydroxymethylfurfural by Lanthanum Salt in Ethanol%乙醇中镧盐催化果糖脱水制备5-羟甲基糠醛的研究

    Institute of Scientific and Technical Information of China (English)

    李秉正; 吴学众

    2011-01-01

    A preliminary study of catalytic dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) was carried out by using ethanol as solvent and lanthanum salt as catalyst. A comparison study indicated that the yields of 5-HMF in ethanol was much larger than those in water. LaCl3 had higher catalytic activity than La(NO3)3. Increasing the catalyst concentration can accelerate the reaction of dehydration of fructose to 5-HMF, but had little effect on increasing the maximum yield of 5-HMF. The yield of 5-HMF,as well as the reaction rate of dehydration of fructose to 5-HMF,increased along with the increase in temperature. The yield of 5-HMF up to 41.6 % was achieved after 20 min at 140℃.%以乙醇为反应溶剂,镧盐为催化剂催化果糖制备5-羟甲基糠醛(5-HMF)进行了初步研究.乙醇作为反应溶剂时,5-HMF产率远高于以水作为反应溶剂.氯化镧与硝酸镧相比具有更好的催化活性.提高催化剂浓度可以增大果糖转化为5-HMF的速率,但是对5-HMF的最大产率影响较小.随着反应温度的提高,果糖转化为5-HMF的速率增大,5-HMF的产率也明显提高.当反应温度为140℃时,反应20 min产率即可达到41.6%.

  15. Preparation of 5-Hydroxymethylfurfural From Glucose With Mesoporus Aluminophosphate as Catalyst%介孔磷酸铝催化葡萄糖制备5-羟甲基糠醛

    Institute of Scientific and Technical Information of China (English)

    陈浩凤; 刘军; 刘春霞

    2015-01-01

    AlPO catalyst was synthesized from Al(NO3)3 and H3PO4 in the presence of citric acid. The samples were characterized by BET, XRD, FT-IR. The AlPO catalyst was evaluated for synthesis of 5-hydroxymethylfurfural from glucose. The effect of n(P)/n(Al), reaction temperature, reaction time, catalyst dosage and glucose quality on the synthesis was investigated. The results show that,under the condition of 10%(wt) catalyst, n(P)/n(Al)=1:1 and 10 mL DMSO as solvent, temperature 150 ℃,time 5 h,HMF yield can reach to 35%.%以硝酸铝和磷酸为原料,采用柠檬酸法制备了介孔磷酸铝材料 AlPO,利用 BET、XRD 和 FT-IR等分析方法对材料的物化性能进行了表征。通过催化葡萄糖转化制备5-羟甲基糠醛(HMF)的反应研究了其催化活性。对材料 P/Al 物质的量比,反应温度,反应时间,催化剂用量和反应底物浓度的考察表明,当n(P)/n(Al)=1:1时,10%(wt)的催化剂用量,在150℃条件下催化葡萄糖反应5 h 后,HMF 的收率可达35%。

  16. 酸性离子液体催化蔗糖转化合成5-羟甲基糠醛%Synthesis of 5-hydroxymethylfurfural from sucrose with acidic ionic liquids as the catalysts

    Institute of Scientific and Technical Information of China (English)

    仝新利; 李梦然

    2011-01-01

    研究了离子液体催化蔗糖合成5-羟甲基糠醛的反应过程.合成并表征了N-甲基吡咯烷酮甲磺酸盐和N-甲基吡咯烷酮硫氢酸盐两种离子液体,并考察了两种离子液体在N,N-二甲基甲酰胺-溴化锂(DMF-LiBr)溶剂体系中催化蔗糖合成5-羟甲基糠醛的反应情况.结果表明,N-甲基吡咯烷酮甲磺酸盐催化效果较好,氮气保护下,在反应温度85℃、反应时间60 min和加入催化剂N-甲基吡咯烷酮甲磺酸盐占蔗糖物质的量的10.0%条件下,蔗糖脱水生成5-羟甲基糠醛的收率可达48.2%.%The synthesis of 5-hydroxymethylfurfural was studied using sucrose as mw material and ionic liquids as the catalysts. The ionic liquids including N-methyl-2-pyrrolidonium methyl sulfonate and N-methyl-2-pyrrolidonium hydrogen suffate was synthesized and characterized, and the catalytic dehydration of sucrose by these ionic liquids was investigated. The results indicated that N-methyl-2-pyrrolidonium methyl sulfonate exhibited better catalytic properties and 5-hydroxymethyffuffural yield of 48.2% was obtained under the condition as follows: reaction time 60 rain, reaction temperature 85 ℃, N2 atmosphere,N-methyl-2-pyrrolidonium methyl sulfonate dosage 10.0% (mole fraction) of sucrose and N, N-dimethylformamide-lithium bromide (DMF-LiBr) as the solvent.

  17. 蜜环菌发酵液中5-羟甲基糠醛提取工艺优化%Optimization of Extracting Process of 5-Hydroxymethylfurfural from Armillaria mellea Fermentation Broth

    Institute of Scientific and Technical Information of China (English)

    陈楠; 焦连庆; 郑毅男; 于敏; 刘晓杰

    2012-01-01

    以蜜环菌发酵液为原料,通过正交试验优选5-羟甲基糠醛的提取工艺.超声提取蜜环菌发酵液中5-羟甲基糠醛,运用高效液相色谱法测定其含量,并用L9(33)正交试验设计,考察提取溶剂量(mLg)、提取时间、提取次数对提取率的影响.蜜环菌发酵液中5-羟甲基糠醛的最佳提取条件为:提取溶剂量6倍量、提取时间20min、提取次数2次.在最佳提取条件下,5-羟甲基糠醛提取率为6.12%.%The orthogonal experimental design method was used to optimize the extracting process of 5-Hydroxymethylfurfural (5-HMF) in the sample of A rmillaria mellea fermentation broth. 5-HMF was extracted by supersonic wave from Armillaria mellea fermentation broth. Then the content of 5-HMF was determined by high performance liquid chromatography. The L, (3s) orthogonal experimental design was used to study the influence of different dosage of extraction solvent (mL: g), extraction time, and the number of extraction on the extraction rate of 5-HMF. The optimum extraction condition: the dosage of extraction solvent was 6 times, extraction time was 20 min, and the number of extraction times was 2. 5-HMF's extraction rate was 6.12% in the best extraction conditions.

  18. Degradation pathways of lamotrigine under advanced treatment by direct UV photolysis, hydroxyl radicals, and ozone.

    Science.gov (United States)

    Keen, Olya S; Ferrer, Imma; Michael Thurman, E; Linden, Karl G

    2014-12-01

    Lamotrigine is recently recognized as a persistent pharmaceutical in the water environment and wastewater effluents. Its degradation was studied under UV and ozone advanced oxidation treatments with reaction kinetics of lamotrigine with ozone (≈4 M(-1)s(-1)), hydroxyl radical [(2.1 ± 0.3) × 10(9)M(-1)s(-1)] and by UV photolysis with low and medium pressure mercury vapor lamps [quantum yields ≈0 and (2.7 ± 0.4)× 10(-4) respectively] determined. All constants were measured at pH 6 and at temperature ≈20°C. The results indicate that lamotrigine is slow to respond to direct photolysis or oxidation by ozone and no attenuation of the contaminant is expected in UV or ozone disinfection applications. The compound reacts rapidly with hydroxyl radicals indicating that advanced oxidation processes would be effective for its treatment. Degradation products were identified under each treatment process using accurate mass time-of-flight spectrometry and pathways of decay were proposed. The main transformation pathways in each process were: dechlorination of the benzene ring during direct photolysis; hydroxyl group addition to the benzene ring during the reaction with hydroxyl radicals; and triazine ring opening after reaction with ozone. Different products that form in each process may be to a varying degree less environmentally stable than the parent lamotrigine. In addition, a novel method of ozone quenching without addition of salts is presented. The new quenching method would allow subsequent mass spectrometry analysis without a solid phase extraction clean-up step. The method involves raising the pH of the sample to approximately 10 for a few seconds and lowering it back and is therefore limited to applications for which temporary pH change is not expected to affect the outcome of the analysis.

  19. Excretion pathways and ruminal disappearance of glyphosate and its degradation product aminomethylphosphonic acid in dairy cows.

    Science.gov (United States)

    von Soosten, D; Meyer, U; Hüther, L; Dänicke, S; Lahrssen-Wiederholt, M; Schafft, H; Spolders, M; Breves, G

    2016-07-01

    From 6 balance experiments with total collection of feces and urine, samples were obtained to investigate the excretion pathways of glyphosate (GLY) in lactating dairy cows. Each experiment lasted for 26d. The first 21d served for adaptation to the diet, and during the remaining 5d collection of total feces and urine was conducted. Dry matter intake and milk yield were recorded daily and milk and feed samples were taken during the sampling periods. In 2 of the 6 experiments, at the sampling period for feces and urine, duodenal contents were collected for 5d. Cows were equipped with cannulas at the dorsal sac of the rumen and the proximal duodenum. Duodenal contents were collected every 2h over 5 consecutive days. The daily duodenal dry matter flow was measured by using chromium oxide as a volume marker. All samples (feed, feces, urine, milk and duodenal contents were analyzed for GLY and aminomethylphosphonic acid (AMPA). Overall, across the 6 experiments (n=32) the range of GLY intake was 0.08 to 6.67mg/d. The main proportion (61±11%; ±SD) of consumed GLY was excreted with feces; whereas excretion by urine was 8±3% of GLY intake. Elimination via milk was negligible. The GLY concentrations above the limit of quantification were not detected in any of the milk samples. A potential ruminal degradation of GLY to AMPA was derived from daily duodenal GLY flow. The apparent ruminal disappearance of GLY intake was 36 and 6%. In conclusion, the results of the present study indicate that the gastrointestinal absorption of GLY is of minor importance and fecal excretion represents the major excretion pathway. A degradation of GLY to AMPA by rumen microbes or a possible retention in the body has to be taken into account. PMID:27108173

  20. Revealing the fate of cell surface human P-glycoprotein (ABCB1): The lysosomal degradation pathway.

    Science.gov (United States)

    Katayama, Kazuhiro; Kapoor, Khyati; Ohnuma, Shinobu; Patel, Atish; Swaim, William; Ambudkar, Indu S; Ambudkar, Suresh V

    2015-10-01

    P-glycoprotein (P-gp) transports a variety of chemically dissimilar amphipathic compounds including anticancer drugs. Although mechanisms of P-gp drug transport are widely studied, the pathways involving its internalization are poorly understood. The present study is aimed at elucidating the pathways involved in degradation of cell surface P-gp. The fate of P-gp at the cell surface was determined by biotinylating cell surface proteins followed by flow cytometry and Western blotting. Our data shows that the half-life of endogenously expressed P-gp is 26.7±1.1 h in human colorectal cancer HCT-15 cells. Treatment of cells with Bafilomycin A1 (BafA1) a vacuolar H+ ATPase inhibitor increased the half-life of P-gp at the cell surface to 36.1±0.5 h. Interestingly, treatment with the proteasomal inhibitors MG132, MG115 or lactacystin alone did not alter the half-life of the protein. When cells were treated with both lysosomal and proteasomal inhibitors (BafA1 and MG132), the half-life was further prolonged to 39-50 h. Functional assays done with rhodamine 123 or calcein-AM, fluorescent substrates of P-gp, indicated that the transport function of P-gp was not affected by either biotinylation or treatment with BafA1 or proteasomal inhibitors. Immunofluorescence studies done with the antibody against lysosomal marker LAMP1 and the P-gp-specific antibody UIC2 in permeabilized cells indicated that intracellular P-gp is primarily localized in the lysosomal compartment. Our results suggest that the lysosomal degradation system could be targeted to increase the sensitivity of P-gp- expressing cancer cells towards chemotherapeutic drugs.

  1. Unusual starch degradation pathway via cyclodextrins in the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus strain 7324.

    Science.gov (United States)

    Labes, Antje; Schönheit, Peter

    2007-12-01

    The hyperthermophilic archaeon Archaeoglobus fulgidus strain 7324 has been shown to grow on starch and sulfate and thus represents the first sulfate reducer able to degrade polymeric sugars. The enzymes involved in starch degradation to glucose 6-phosphate were studied. In extracts of starch-grown cells the activities of the classical starch degradation enzymes, alpha-amylase and amylopullulanase, could not be detected. Instead, evidence is presented here that A. fulgidus utilizes an unusual pathway of starch degradation involving cyclodextrins as intermediates. The pathway comprises the combined action of an extracellular cyclodextrin glucanotransferase (CGTase) converting starch to cyclodextrins and the intracellular conversion of cyclodextrins to glucose 6-phosphate via cyclodextrinase (CDase), maltodextrin phosphorylase (Mal-P), and phosphoglucomutase (PGM). These enzymes, which are all induced after growth on starch, were characterized. CGTase catalyzed the conversion of starch to mainly beta-cyclodextrin. The gene encoding CGTase was cloned and sequenced and showed highest similarity to a glucanotransferase from Thermococcus litoralis. After transport of the cyclodextrins into the cell by a transport system to be defined, these molecules are linearized via a CDase, catalyzing exclusively the ring opening of the cyclodextrins to the respective maltooligodextrins. These are degraded by a Mal-P to glucose 1-phosphate. Finally, PGM catalyzes the conversion of glucose 1-phosphate to glucose 6-phosphate, which is further degraded to pyruvate via the modified Embden-Meyerhof pathway.

  2. Characteristics of the Thermal Degradation of Glucose and Maltose Solutions

    OpenAIRE

    Woo, Koan Sik; Kim, Hyun Young; Hwang, In Guk; Lee, Sang Hoon; Jeong, Heon Sang

    2015-01-01

    In order to investigate the thermal degradation of glucose and maltose solutions after high temperature and high pressure (HTHP) treatment, the samples were treated at temperatures of 110, 120, 130, 140, and 150°C for 1, 2, 3, 4, and 5 h in an apparatus for HTHP treatment. Glucose and maltose solutions (20% w/w) were prepared by weighing glucose and maltose and adding distilled water in the desired proportion. Chromaticity, pH, organic acids, 5-hydroxymethylfurfural (HMF), free sugar contents...

  3. Purification of 5-hydroxymethylfurfural (hmf) by crystallization

    DEFF Research Database (Denmark)

    2013-01-01

    This invention relates to an efficient procedure for purifying HMF by crystallization at low temperature from an organic solvent.......This invention relates to an efficient procedure for purifying HMF by crystallization at low temperature from an organic solvent....

  4. Connecting lignin-degradation pathway with pretreatment inhibitor sensitivity of Cupriavidus necator

    Directory of Open Access Journals (Sweden)

    Wei eWang

    2014-05-01

    Full Text Available To produce lignocellulosic biofuels economically, the complete release of monomers from the plant cell wall components, cellulose, hemicellulose and lignin, through pretreatment and hydrolysis (both enzymatic and chemical, and the efficient utilization of these monomers as carbon sources, is crucial. In addition, the identification and development of robust microbial biofuel production strains that can tolerate the toxic compounds generated during pretreatment and hydrolysis is also essential. In this work, Cupriavidus necator was selected due to its capabilities for utilizing lignin monomers and producing polyhydroxylbutyrate (PHB, a bioplastic as well as an advanced biofuel intermediate. We characterized the growth kinetics of C. necator in pretreated corn stover slurry as well as individually in the presence of 11 potentially toxic compounds in the saccharified slurry. We found that C. necator was sensitive to the saccharified slurry produced from dilute acid pretreated corn stover. Five out of 11 compounds within the slurry were characterized as toxic to C. necator, namely ammonium acetate, furfural, hydroxymethylfurfural (HMF, benzoic acid, and p-coumaric acid. Aldehydes (e.g., furfural and HMF were more toxic than the acetate and the lignin degradation products benzoic acid and p-coumaric acid; furfural was identified as the most toxic compound. Although toxic to C. necator at high concentration, ammonium acetate, benzoic acid, and p-coumaric acid could be utilized by C. necator with a stimulating effect on C. necator growth. Consequently, the lignin degradation pathway of C. necator was reconstructed based on genomic information and literature. The efficient conversion of intermediate catechol to downstream products of cis,cis-muconate or 2-hydroxymuconate-6-semialdehyde may help improve the robustness of C. necator to benzoic acid and p-coumaric acid as well as improve PHB productivity.

  5. Connecting Lignin-Degradation Pathway with Pre-Treatment Inhibitor Sensitivity of Cupriavidus necator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Yang, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hunsinger, G. B. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pienkos, P. T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Johnson, D. K. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-05-27

    In order to produce lignocellulosic biofuels economically, the complete release of monomers from the plant cell wall components, cellulose, hemicellulose, and lignin, through pre-treatment and hydrolysis (both enzymatic and chemical), and the efficient utilization of these monomers as carbon sources, is crucial. In addition, the identification and development of robust microbial biofuel production strains that can tolerate the toxic compounds generated during pre-treatment and hydrolysis is also essential. In this work, Cupriavidus necator was selected due to its capabilities for utilizing lignin monomers and producing polyhydroxylbutyrate (PHB), a bioplastic as well as an advanced biofuel intermediate. We characterized the growth kinetics of C. necator in pre-treated corn stover slurry as well as individually in the pre-sence of 11 potentially toxic compounds in the saccharified slurry. We found that C. necator was sensitive to the saccharified slurry produced from dilute acid pre-treated corn stover. Five out of 11 compounds within the slurry were characterized as toxic to C. necator, namely ammonium acetate, furfural, hydroxymethylfurfural (HMF), benzoic acid, and p-coumaric acid. Aldehydes (e.g., furfural and HMF) were more toxic than the acetate and the lignin degradation products benzoic acid and p-coumaric acid; furfural was identified as the most toxic compound. Although toxic to C. necator at high concentration, ammonium acetate, benzoic acid, and p-coumaric acid could be utilized by C. necator with a stimulating effect on C. necator growth. Consequently, the lignin degradation pathway of C. necator was reconstructed based on genomic information and literature. The efficient conversion of intermediate catechol to downstream products of cis,cis-muconate or 2-hydroxymuconate-6-semialdehyde may help improve the robustness of C. necator to benzoic acid and p-coumaric acid as well as improve PHB productivity.

  6. The Whole Genome Sequence of Sphingobium chlorophenolicum L-1: Insights into the Evolution of the Pentachlorophenol Degradation Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Copley, Shelley D. [University of Colorado; Rokicki, Joseph [University of Colorado; Turner, Pernilla [University of Colorado; Daligault, Hajnalka E. [Los Alamos National Laboratory (LANL); Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL

    2012-01-01

    Sphingobium chlorophenolicum Strain L-1 can mineralize the toxic pesticide pentachlorophenol (PCP). We have sequenced the genome of S. chlorophenolicum Strain L-1. The genome consists of a primary chromosome that encodes most of the genes for core processes, a secondary chromosome that encodes primarily genes that appear to be involved in environmental adaptation, and a small plasmid. The genes responsible for degradation of PCP are found on chromosome 2. We have compared the genomes of S. chlorophenolicum Strain L-1 and Sphingobium japonicum, a closely related Sphingomonad that degrades lindane. Our analysis suggests that the genes encoding the first three enzymes in the PCP degradation pathway were acquired via two different horizontal gene transfer events, and the genes encoding the final two enzymes in the pathway were acquired from the most recent common ancestor of these two bacteria.

  7. Insights from 14C into C loss pathways in degraded peatlands

    Science.gov (United States)

    Evans, Martin; Evans, Chris; Allott, Tim; Stimson, Andrew; Goulsbra, Claire

    2016-04-01

    Peatlands are important global stores of terrestrial carbon. Lowered water tables due to changing climate and direct or indirect human intervention produce a deeper aerobic zone and have the potential to enhance loss of stored carbon from the peat profile. The quasi continuous accumulation of organic matter in active peatlands means that the age of fluvial dissolved organic carbon exported from peatland systems is related to the source depth in the peat profile. Consequently 14C analysis of DOC in waters draining peatlands has the potential not only to tell us about the source of fluvial carbon and the stability of the peatland but also about the dominant hydrological pathways in the peatland system. This paper will present new radiocarbon determinations from peatland streams draining the heavily eroded peatlands of the southern Pennine uplands in the UK. These blanket peatland systems are highly degraded, with extensive bare peat and gully erosion resulting from air pollution during the industrial revolution, overgrazing, wildfire and climatic changes. Deep and extensive gullying has significantly modified the hydrology of these systems leading to local and more widespread drawdown of water table. 14C data from DOC in drainage waters are presented from two catchments; one with extensive gully erosion and the other with a combination of gully erosion and sheet erosion of the peat. At the gully eroded site DOC in drainage waters is as old as 160 BP but at the site with extensive sheet erosion dates of up to 1069 BP are amongst the oldest recorded from blanket peatland globally These data indicate significant degradation of stored carbon from the eroding peatlands. Initial comparisons of the 14C data with modelled water table for the catchments and depth-age curves for catchment peats suggests that erosion of the peat surface, allowing decomposition of exposed older organic material is a potential mechanism producing aged carbon from the eroded catchment. This

  8. Ubiquitin proteasome-dependent degradation of the transcriptional coactivator PGC-1{alpha} via the N-terminal pathway.

    Science.gov (United States)

    Trausch-Azar, Julie; Leone, Teresa C; Kelly, Daniel P; Schwartz, Alan L

    2010-12-17

    PGC-1α is a potent, inducible transcriptional coactivator that exerts control on mitochondrial biogenesis and multiple cellular energy metabolic pathways. PGC-1α levels are controlled in a highly dynamic manner reflecting regulation at both transcriptional and post-transcriptional levels. Here, we demonstrate that PGC-1α is rapidly degraded in the nucleus (t(½ 0.3 h) via the ubiquitin proteasome system. An N-terminal deletion mutant of 182 residues, PGC182, as well as a lysine-less mutant form, are nuclear and rapidly degraded (t(½) 0.5 h), consistent with degradation via the N terminus-dependent ubiquitin subpathway. Both PGC-1α and PGC182 degradation rates are increased in cells under low serum conditions. However, a naturally occurring N-terminal splice variant of 270 residues, NT-PGC-1α is cytoplasmic and stable (t(½>7 h), providing additional evidence that PGC-1α is degraded in the nucleus. These results strongly suggest that the nuclear N terminus-dependent ubiquitin proteasome pathway governs PGC-1α cellular degradation. In contrast, the cellular localization of NT-PCG-1α results in a longer-half-life and possible distinct temporal and potentially biological actions.

  9. Determination of 5-hydroxymethylfurfural in fruit juice concentrate and fruit fructose by HPLC%高效液相色谱法测定浓缩果汁及水果果糖中5-羟甲基糠醛

    Institute of Scientific and Technical Information of China (English)

    孔祥虹; 李小军; 何强; 高军刚; 吴双民

    2012-01-01

    A HPLC method was established for the determination of 5-hydroxymethylfurfural(5-HMF)in fruit juice concentrate and fruit fructose.The sample was diluted with water, separated by using Inetrsil ODS-3 C18 (250mm × 4.6mm,5μm) chromatographic column.The method showed that a good linearity within the range of 1.0-25.0mg/L( r = 9998).The LOD of 5-HMF was 0.2mg/kg, the average recoveries from 82.2% to 103.3%, the relative standard deviation(RSD) from 0.62% to 1.25%.The HPLC method is quick, accurate, sensitive and suitable for determining the content of 5-HMF in fruit juice concentrate.%建立了浓缩苹果汁、浓缩梨汁和水果果糖中的5-羟甲基糠醛的高效液相色谱(HPLC)检测方法。样品用甲醇溶解后,经水稀释,Inetrsil ODS-3 C18(250mm×4.6mm,5μm)色谱柱分离,紫外检测器在282nm处进行检测;5-羟甲基糠醛在1.0-25.0mg/L范围内线性关系良好,相关系数为0.9998,回收率为82.2%~103.3%,精密度(RSD)为0.62%-1.25%,方法的检出限(LOD)为0.2mg/kg。本方法具有快速、简单、灵敏度高、适用范围广等特点,可以满足果汁中5-羟甲基糠醛的分析要求。

  10. Study on antioxidation capability of fructose-oligosaccharide and 5- hydroxymethylfurfural%低聚蔗果糖及其5-羟甲基糠醛抗氧化能力研究

    Institute of Scientific and Technical Information of China (English)

    宋玉蓉; 刘云; 乐国伟; 张蓉; 施用晖

    2010-01-01

    目的:研究微渡辅助合成低聚蔗果糖(W-FOS)及其在合成过程中产生的5-HMF(5-hydroxymethylfurfural)抗氧化能力.方法:测定W-FOS及5-HMF清除DPPH、ABTS~+能力;清洁级昆明小鼠60只,随机分6组:对照组、高脂组(脂肪含量20%)、高脂+0.5%E-FOS(酶法合成低聚果糖)组、高脂+0.5%W-FOS+5-HMF组(5-HMF含量分别为0.20%、0.02%、0.0%).饲喂5w后测定机体抗氧化指标水平.结果:W-FOS具有清除DPPH、ABTS~+能力,且5-HMF能提高其清除力;E-FOS、W-FOS+5-HMF组能使高脂日粮小鼠血脂水平得到显著恢复(P<0.05);W-FOS+5-HMF组能使高脂日粮小鼠血脂水平显著降低(P<0.05);添加含中低、高水平5-HMF的W-FOS分别能显著恢复高脂日粮小鼠血浆T-AOC、CAT、MDA、ROS和CAT、ROS水平;含中低水平5-HMF的W-FOS对高脂日粮小鼠肝脏GSH-Px、MDA、ROS的保护作用优于高水平5-HMF的W-FOS.结论:W-FOS和5-HMF都具有清除DPPH、ABTS~+的能力;0.5%W-FOS及其5-HMF水平为0.00%~0.02%对,对高脂日粮小鼠的血脂水平、血浆、肝脏的抗氧化能力均具有良好的保护作用.

  11. Determination of the Contents of 5-hydroxymethylfurfural in DangShen by HPLC%HPLC法测定党参中5-羟甲基糠醛的含量

    Institute of Scientific and Technical Information of China (English)

    王宇; 张玉兰

    2014-01-01

    目的:建立党参中己糖降解产物5-羟甲基糠醛(5-HMF)的含量测定方法,对党参药材中的5-羟甲基糠醛进行含量测定。方法:采用Agilent Extend-C18(250 mm×4.6 mm,5μm)色谱柱,以乙腈-0.3%醋酸溶液(3∶97)为流动相,检测波长284 nm,流速1.0 mL/min,柱温30℃。结果:5-羟甲基糠醛在浓度为2.538~63.45μg/mL范围内与峰面积具有良好的线性关系(r=0.9998),精密度和重复性的RSD分别为0.8%和2.5%。结论:该方法操作简便,结果准确可靠,可用于党参中5-羟甲基糠醛的含量测定,为进一步评价党参的安全性提供参考。%Objective:To establish the determination method for 5-hydroxymethylfurfural (5-HMF) in Dang-Shen (Radix Codonopsis Pilosulae) and determine its contents. Methods:Agilent Extend-C18 (250 mm×4.6 mm, 5μm) chromatographic column was adopted with the mobile phase of acetonitrile-0.3% acetum (3:97), detection wave-length was 284nm, flow rate was 1.0mL/min, column temperature was 30℃. Results:It showed better linear rela-tionship in the range between 2.538 and 63.45μg/mL and peak area (r=0.999 8), accuracy and repeatability RSD were 0.8%and 2.5%respectively. Conclusion:The method, simple and reliable, could be used to the determination of 5-HMF contained in DangShen, which could provide reference for further assessment of the safety of DangShen.

  12. Ozonation degradation of microcystin-LR in aqueous solution: intermediates, byproducts and pathways.

    Science.gov (United States)

    Chang, Jing; Chen, Zhong-lin; Wang, Zhe; Shen, Ji-min; Chen, Qian; Kang, Jing; Yang, Lei; Liu, Xiao-wei; Nie, Chang-xin

    2014-10-15

    The intermediates and byproducts formed during the ozonation of microcystin-LR (MC-LR, m/z = 995.5) and the probable degradation pathway were investigated at different initial molar ratios of ozone to MC-LR ([O3]0/[MC-LR]0). Seven reaction intermediates with m/z ≥ 795.4 were observed by LC/MS, and four of them (m/z = 815.4, 827.3, 853.3 and 855.3) have not been previously reported. Meanwhile, six aldehyde-based byproducts with molecular weights of 30-160 were detected for the first time. Intermediates structures demonstrated that ozone reacted with two sites of MC-LR: the diene bonds in the Adda side chain and the Mdha amino acid in the cyclic structure. The fragment from the Adda side chain oxidative cleavage could be further oxidized to an aldehyde with a molecular weight of 160 at low [O3]0/[MC-LR]0. Meanwhile, the polypeptide structure of MC-LR was difficult to be further oxidized, unless [O3]0/[MC-LR]0 > 10. After further oxidation of the intermediates, five other aldehyde-based byproducts were detected by GC/MS: formaldehyde, acetaldehyde, isovaleraldehyde, glyoxal and methylglyoxal. Formaldehyde, isovaleraldehyde and methylglyoxal were the dominant species. The yields of the aldehydes varied greatly, depending on the value of [O3]0/[MC-LR]0.

  13. REGγ regulates ERα degradation via ubiquitin–proteasome pathway in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Fan; Liang, Yan [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Bi, Jiong [Laboratory of General Surgery, First Affiliated Hospital, Sun Yet-sen University, Guangzhou 510080 (China); Chen, Li; Zhang, Fan [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Cui, Youhong [Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Jiang, Jun, E-mail: jcbd@medmail.com.cn [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China)

    2015-01-02

    Highlights: • High expression of REGγ is correlated with ERα status and poor clinical features. • Cell growth, mobility and invasion are significantly impaired by REGγ knockdown. • REGγ indirectly regulates ERα protein expression. - Abstract: REGγ is a proteasome coactivator which regulates proteolytic activity in eukaryotic cells. Abundant lines of evidence have showed that REGγ is over expressed in a number of human carcinomas. However, its precise role in the pathogenesis of cancer is still unclear. In this study, by examining 200 human breast cancer specimens, we demonstrated that REGγ was highly expressed in breast cancers, and the expression of REGγ was positively correlated with breast cancer patient estrogen receptor alpha (ERα) status. Moreover, the expression of REGγ was found positively associated with poor clinical features and low survival rates in ERα positive breast cancer patients. Further cell culture studies using MCF7 and BT474 breast cancer cell lines showed that cell proliferation, motility, and invasion capacities were decreased significantly by REGγ knockdown. Lastly, we demonstrated that REGγ indirectly regulates the degradation of ERα protein via ubiquitin–proteasome pathway. In conclusion, our findings provide the evidence that REGγ expression was positively correlated with ERα status and poor clinical prognosis in ERα positive breast cancer patients. As well, we disclose a new connection between the two molecules that are both highly expressed in most breast cancer cases.

  14. Assessing degradation and recovery pathways in lakes impacted by eutrophication using the sediment record

    Directory of Open Access Journals (Sweden)

    Helen eBennion

    2015-08-01

    Full Text Available Efforts to restore enriched lakes have increased yet there remains uncertainty about whether restoration targets can be achieved and over what timescale. Paleoecological techniques, principally diatom analyses, were used to examine the degree of impact and recovery in 12 European lakes subject to eutrophication and subsequent reduction in nutrient loading. Dissimilarity scores showed that all sites experienced progressive deviation from the reference sample (core bottom prior to nutrient reduction, and principal curves indicated gradual compositional change with enrichment. When additive models were applied to the latter, the changes were statistically significant in 9 of the 12 sites. Shifts in diatom composition following reduction in nutrient loading were more equivocal, with a reversal towards the reference flora seen only in four of the deep lakes and one of the shallow lakes. Of these, only two were significant (Lake Bled and Mjøsa. Alternative nutrient sources seem to explain the lack of apparent recovery in the other deep lakes. In three shallow lakes diatom assemblages were replaced by a community associated with lower productivity but not the one seen prior to enrichment. Internal loading and top down control may influence recovery in shallow lakes and climate change may have confounded recovery in several of the study sites. Hence, ecosystem recovery is not simply a reversal of the degradation pathway and may take several decades to complete or, for some lakes, may not take place at all. By assessing ecological change over a decadal to centennial timescale, the study highlights the important role that paleolimnology can play in establishing a benchmark against which managers can evaluate the degree to which their restoration efforts are successful.

  15. Different pathways of degradation of SP-A and saturated phosphatidylcholine by alveolar macrophages.

    Science.gov (United States)

    Baritussio, A; Alberti, A; Armanini, D; Meloni, F; Bruttomesso, D

    2000-07-01

    Alveolar macrophages degrade surfactant protein (SP) A and saturated phosphatidycholine [dipalmitoylphosphatidylcholine (DPPC)]. To clarify this process, using rabbit alveolar macrophages, we analyzed the effect of drugs known to affect phagocytosis, pinocytosis, clathrin-mediated uptake, caveolae, the cytoskeleton, lysosomal pH, protein kinase C, and phosphatidylinositol 3-kinase (PI3K) on the degradation of SP-A and DPPC. We found the following: 1) SP-A binds to the plasma membrane, is rapidly internalized, and then moves toward degradative compartments. Uptake could be clathrin mediated, whereas phagocytosis, pinocytosis, or the use of caveolae are less likely. An intact cytoskeleton and an acidic milieu are necessary for the degradation of SP-A. 2) Stimulation of protein kinase C increases the degradation of SP-A. 3) PI3K influences the degradation of SP-A by regulating both the speed of internalization and subsequent intracellular steps, but its inhibition does not prevent SP-A from reaching the lysosomal compartment. 4) The degradation of DPPC is unaffected by most of the treatments able to influence the degradation of SP-A. Thus it appears that DPPC is degraded by alveolar macrophages through mechanisms very different from those utilized for the degradation of SP-A. PMID:10893207

  16. New pathway for degradation of sulfonated azo dyes by microbial peroxidases of Phanerochaete chrysosporium and Streptomyces chromofuscus.

    OpenAIRE

    Goszczynski, S; Paszczynski, A; Pasti-Grigsby, M B; Crawford, R L; Crawford, D. L.

    1994-01-01

    Pathways for the degradation of 3,5-dimethyl-4-hydroxy-azobenzene-4'-sulfonic acid (I) and 3-methoxy-4-hydroxyazobenzene-4'-sulfonamide (II) by the manganese peroxidase and ligninase of Phanerochaete chrysosporium and by the peroxidase of Streptomyces chromofuscus have been proposed. Twelve metabolic products were found, and their mechanisms of formation were explained. Preliminary oxidative activation of the dyes resulted in the formation of cationic species, making the molecules vulnerable ...

  17. 不同热作用条件下牛乳中5-HMF生成量的变化研究%Study on the Quantities Change of the 5-Hydroxymethylfurfural in Milk under the Different Heat Treatments

    Institute of Scientific and Technical Information of China (English)

    高萌; 葛武鹏; 张小军; 崔璐璐; 秦立虎

    2012-01-01

    : To discuss the 5-HMF as the milk heat degree validation of target sensitivity and direct the scientific of determine the different heat treatment processes. A high performance liquid chromatographic (HPLC) method was developed for the quantities change of 5-Hydroxymethylfurfural (5-HMF) in milk under the different heating temperature and time, revealed its regularity changes. The results showed that: First, with increasing the heating temperature and heating time, the 5-HMF quantities in pasteurizing milk and instantaneous ultra high temperature sterilizing (UHT) milk all had changed. The higher the heating temperature and the longer the heating time the UHT was, the higher quantities of 5-HMF had. Second, Using this method could rapid determined the rule in quantities of 5-HMF and existed a well linear relationship between peak area and content, the determination results had high accuracy and reproducibility, and the recovery percent of 5-HMF was 90.63%-96.23%. The conclusion was that: 5-HMF as mark was scientific and feasible, based on this, establishment of the liquid milk for process parameters was: the pasteurization dairy temperature should be controlled at ( 85±2 ) ℃, the time for 15 s; the UHT dairy temperature should be controlled at ( 137±2 ) ℃, the time for 4 s.%旨在探讨5-羟甲基糠醛(5-HMF)作为牛乳中热作用程度标示物的可行性并指导不同热处理工艺参数确定的科学性。采用高效液相色谱(HPLC)法对不同温度和时间处理条件下牛乳中的5-HMF生成量变化进行分析比较,揭示其规律性变化。结果表明:(1)随着加热温度的升高和时间的延长,巴杀乳和超高温瞬时灭菌(UHT)乳中5-HMF的生成量均有相应变化,且加热温度越高,时间越长,5-HMF的生成量越高,表明5-HMF作为牛乳受热作用程度标示物可行。(2)可以快速测定牛乳中5-HMF生成量变化,结果具有

  18. Researching in different activated carbon for absorption of 5-hydroxymethylfurfural and decolorization of fructose syrup%不同活性炭对果葡糖浆脱色性能及5-羟甲基糠醛吸附力的比较

    Institute of Scientific and Technical Information of China (English)

    伍伯良; 许永苗; 叶晓蕾; 黄智钧; 杨曦宇

    2014-01-01

    5-羟甲基糠醛是影响果葡糖浆风味的异味物质之一,在果葡糖浆的生产工艺上无法完全去除,需要通过调节工艺参数得以控制。通过分析活性炭对5-羟甲基糠醛的吸附力及对糖浆的脱色效果,得出了不同工艺制造的粉状活性炭的优劣性,为果葡糖浆生产厂家活性炭的选择及添加比例提供参考。%5-hydroxymethylfurfural is one of the off-odor compounds that influence the flavor of high fructose syrup, it can't be completely wiped up in fructose production process and can be controlled by adjusting experimental operating parameters. By analyzing the effects of activated carbon for absorption of 5-hydroxymethylfurfural by and decolorization of fructose syrup, the advantages and disadvantages of different activated carbon were found out. This result is available for the reference to choose and use activated carbon in producing fructose syrup.

  19. TRIM22 Inhibits the TRAF6-stimulated NF-κB Pathway by Targeting TAB2 for Degradation

    Institute of Scientific and Technical Information of China (English)

    Hui Qiu; Fang Huang; Han Xiao; Binlian Sun; Rongge Yang

    2013-01-01

    Tripartite motif containing 22 (TRIM22),a member of the TRIM/RBCC family,has been reported to activate the nuclear factor-kappa B (NF-κB) pathway in unstimulated macrophage cell lines,but the detailed mechanisms governing this activation remains unclear.We investigated this mechanism in HEK293T cells.We found that overexpression of TRIM22 could activate the NF-κB pathway and conversely,could inhibit the tumor necrosis factor receptor-associated factor 6 (TRAF6)-stimulated NF-κB pathway in HEK293T cells.Further experiments showed that TRIM22 could decrease the self-ubiquitination of TRAF6,and interact with and degrade transforming growth factor-β activated kinase 1 binding protein 2 (TAB2),and that these effects could be partially rescued by a TRIM22 RING domain deletion mutant.Collectively,our data indicate that overexpression of TRIM22 may negatively regulate the TRAF6-stimulated NF-κB pathway by interacting with and degrading TAB2.

  20. 乙酸、糠醛和5-羟甲基糠醛对产酸克雷伯氏菌发酵生产2,3-丁二醇的影响%Effect of acetic acid, furfural and 5-hydroxymethylfurfural on production of 2,3-butanediol by Klebsiella oxytoca

    Institute of Scientific and Technical Information of China (English)

    吴晶; 程可可; 李文英; 冯杰; 张建安

    2013-01-01

    To get the tolerability and consumption of Klebsiella oxytoca on major inhibitors in lignocelluloses hydrolysate, we studied the effect of acetic acid, furfural and 5-hydroxymethylfurfural on production of 2,3-butanediol by Klebsiella oxytoca. The metabolites of furfural and 5-hydroxymethylfurfural were measured. The results show that when acetic acid, furfural and 5-hydroxymethylfurfural was individually added, tolerance threshold for Klebsiella oxytoca was 30 g/L, 4 g/L and 5 g/L, respectively. Acetic acid was likely used as substrate to produce 2,3-butanediol. The yield of 2,3-butanediol increased when acetic acid concentration was lower than 30 g/L. In the fermentation, more than 70% 5-hydroxymethylfurfural was converted to 2,5-furandimethanol. All furfural and the rest of 5-hydroxymethylfurfural were metabolized by Klebsiella oxytoca. It showed that in the detoxification process of 2,3-butanediol production using lignocelluloses hydrolysate, furfural should be given priority to remove and a certain concentration of acetic acid is not need to removal.%为了解产酸克雷伯氏菌对木质纤维素水解液中主要抑制物的耐受和代谢,考察了产酸克雷伯氏菌发酵生产2,3-丁二醇(2,3-butanediol,2,3-BDO)过程中对3种发酵抑制物乙酸、糠醛和5-羟甲基糠醛(5-hydroxymethylfurfural HMF)的耐受以及抑制物浓度的变化,检测了糠醛和HMF的代谢产物.结果表明:产酸克雷伯氏菌对乙酸、糠醛和HMF的耐受浓度分别为30 g/L、4 g/L和5 g/L.并且部分乙酸可作为生产2,3-丁二醇的底物,在0~30 g/L浓度范围内可提高2,3-丁二醇的产量.发酵过程中产酸克雷伯氏菌可将HMF和糠醛全部转化,其中约70%HMF被转化为2,5-呋喃二甲醇,30%HMF和全部糠醛被菌体代谢.研究表明在木质纤维素水解液生产2,3-丁二醇的脱毒过程中可优先考虑脱除糠醛,一定浓度的乙酸可以不用脱除.

  1. Adsorption and Photocatalytic Decomposition of the β-Blocker Metoprolol in Aqueous Titanium Dioxide Suspensions: Kinetics, Intermediates, and Degradation Pathways

    Directory of Open Access Journals (Sweden)

    Violette Romero

    2013-01-01

    Full Text Available This study reports the photocatalytic degradation of the β-blocker metoprolol (MET using TiO2 suspended as catalyst. A series of photoexperiments were carried out by a UV lamp, emitting in the 250–400 nm range, providing information about the absorption of radiation in the photoreactor wall. The influence of the radiation wavelength on the MET photooxidation rate was investigated using a filter cutting out wavelengths shorter than 280 nm. Effects of photolysis and adsorption at different initial pH were studied to evaluate noncatalytic degradation for this pharmaceutical. MET adsorption onto titania was fitted to two-parameter Langmuir isotherm. From adsorption results it appears that the photocatalytic degradation can occur mainly on the surface of TiO2. MET removed by photocatalysis was 100% conditions within 300 min, while only 26% was achieved by photolysis at the same time. TiO2 photocatalysis degradation of MET in the first stage of the reaction followed approximately a pseudo-first-order model. The major reaction intermediates were identified by LC/MS analysis such as 3-(propan-2-ylaminopropane-1,2-diol or 3-aminoprop-1-en-2-ol. Based on the identified intermediates, a photocatalytic degradation pathway was proposed, including the cleavage of side chain and the hydroxylation addition to the parent compounds.

  2. Metabolism of 2-Chloro-4-Nitroaniline via Novel Aerobic Degradation Pathway by Rhodococcus sp. Strain MB-P1

    Science.gov (United States)

    Khan, Fazlurrahman; Pal, Deepika; Vikram, Surendra; Cameotra, Swaranjit Singh

    2013-01-01

    2-chloro-4-nitroaniline (2-C-4-NA) is used as an intermediate in the manufacture of dyes, pharmaceuticals, corrosion inhibitor and also used in the synthesis of niclosamide, a molluscicide. It is marked as a black-listed substance due to its poor biodegradability. We report biodegradation of 2-C-4-NA and its pathway characterization by Rhodococcus sp. strain MB-P1 under aerobic conditions. The strain MB-P1 utilizes 2-C-4-NA as the sole carbon, nitrogen, and energy source. In the growth medium, the degradation of 2-C-4-NA occurs with the release of nitrite ions, chloride ions, and ammonia. During the resting cell studies, the 2-C-4-NA-induced cells of strain MB-P1 transformed 2-C-4-NA stoichiometrically to 4-amino-3-chlorophenol (4-A-3-CP), which subsequently gets transformed to 6-chlorohydroxyquinol (6-CHQ) metabolite. Enzyme assays by cell-free lysates prepared from 2-C-4-NA-induced MB-P1 cells, demonstrated that the first enzyme in the 2-C-4-NA degradation pathway is a flavin-dependent monooxygenase that catalyzes the stoichiometric removal of nitro group and production of 4-A-3-CP. Oxygen uptake studies on 4-A-3-CP and related anilines by 2-C-4-NA-induced MB-P1 cells demonstrated the involvement of aniline dioxygenase in the second step of 2-C-4-NA degradation. This is the first report showing 2-C-4-NA degradation and elucidation of corresponding metabolic pathway by an aerobic bacterium. PMID:23614030

  3. Metabolism of 2-chloro-4-nitroaniline via novel aerobic degradation pathway by Rhodococcus sp. strain MB-P1.

    Directory of Open Access Journals (Sweden)

    Fazlurrahman Khan

    Full Text Available 2-chloro-4-nitroaniline (2-C-4-NA is used as an intermediate in the manufacture of dyes, pharmaceuticals, corrosion inhibitor and also used in the synthesis of niclosamide, a molluscicide. It is marked as a black-listed substance due to its poor biodegradability. We report biodegradation of 2-C-4-NA and its pathway characterization by Rhodococcus sp. strain MB-P1 under aerobic conditions. The strain MB-P1 utilizes 2-C-4-NA as the sole carbon, nitrogen, and energy source. In the growth medium, the degradation of 2-C-4-NA occurs with the release of nitrite ions, chloride ions, and ammonia. During the resting cell studies, the 2-C-4-NA-induced cells of strain MB-P1 transformed 2-C-4-NA stoichiometrically to 4-amino-3-chlorophenol (4-A-3-CP, which subsequently gets transformed to 6-chlorohydroxyquinol (6-CHQ metabolite. Enzyme assays by cell-free lysates prepared from 2-C-4-NA-induced MB-P1 cells, demonstrated that the first enzyme in the 2-C-4-NA degradation pathway is a flavin-dependent monooxygenase that catalyzes the stoichiometric removal of nitro group and production of 4-A-3-CP. Oxygen uptake studies on 4-A-3-CP and related anilines by 2-C-4-NA-induced MB-P1 cells demonstrated the involvement of aniline dioxygenase in the second step of 2-C-4-NA degradation. This is the first report showing 2-C-4-NA degradation and elucidation of corresponding metabolic pathway by an aerobic bacterium.

  4. Metabolism of 2-chloro-4-nitroaniline via novel aerobic degradation pathway by Rhodococcus sp. strain MB-P1.

    Science.gov (United States)

    Khan, Fazlurrahman; Pal, Deepika; Vikram, Surendra; Cameotra, Swaranjit Singh

    2013-01-01

    2-chloro-4-nitroaniline (2-C-4-NA) is used as an intermediate in the manufacture of dyes, pharmaceuticals, corrosion inhibitor and also used in the synthesis of niclosamide, a molluscicide. It is marked as a black-listed substance due to its poor biodegradability. We report biodegradation of 2-C-4-NA and its pathway characterization by Rhodococcus sp. strain MB-P1 under aerobic conditions. The strain MB-P1 utilizes 2-C-4-NA as the sole carbon, nitrogen, and energy source. In the growth medium, the degradation of 2-C-4-NA occurs with the release of nitrite ions, chloride ions, and ammonia. During the resting cell studies, the 2-C-4-NA-induced cells of strain MB-P1 transformed 2-C-4-NA stoichiometrically to 4-amino-3-chlorophenol (4-A-3-CP), which subsequently gets transformed to 6-chlorohydroxyquinol (6-CHQ) metabolite. Enzyme assays by cell-free lysates prepared from 2-C-4-NA-induced MB-P1 cells, demonstrated that the first enzyme in the 2-C-4-NA degradation pathway is a flavin-dependent monooxygenase that catalyzes the stoichiometric removal of nitro group and production of 4-A-3-CP. Oxygen uptake studies on 4-A-3-CP and related anilines by 2-C-4-NA-induced MB-P1 cells demonstrated the involvement of aniline dioxygenase in the second step of 2-C-4-NA degradation. This is the first report showing 2-C-4-NA degradation and elucidation of corresponding metabolic pathway by an aerobic bacterium. PMID:23614030

  5. Characterization of a new degradation product of nifedipine formed on catalysis by atenolol: A typical case of alteration of degradation pathway of one drug by another.

    Science.gov (United States)

    Handa, Tarun; Singh, Saranjit; Singh, Inder Pal

    2014-02-01

    An increasing interest is being shown throughout the world on the use of fixed-dose combinations of drugs in the therapy of select diseases, like cardiovascular diseases, due to their multiple advantages. Though the main criterion for combining drugs in a single dosage form is the rationale, but consideration like stability of formulation is equally important, due to an added aspect of drug-drug interaction. The objective of this study was to evaluate interaction among the drugs in an antihypertensive combination of nifedipine and atenolol. Nifedipine is a known light sensitive drug, which degrades via intra-molecular mechanisms to nitro- and nitroso-pyridine analogs, along with a few minor secondary products that are formed through inter-molecular interactions amongst primary degradation products and their intermediates. Atenolol is reasonably stable weakly basic drug that is mainly hydrolyzed at acetamide terminal amide moiety to its corresponding carboxylic acid. To the best of our knowledge, there is no known information on chemical compatibility among the two drugs. The present study involved subjecting of nifedipine, atenolol and their combination to a variety of accelerated and stress conditions. HPLC studies revealed formation of a new product in the mixture of two drugs (∼2%), which was also generated from nifedipine alone, but at trace levels (<0.1%). The product was isolated by preparative chromatography and subjected to indepth studies for its characterization. Ultra-violet, FT-IR, mass spectrometric and nuclear magnetic resonance spectroscopic studies highlighted that the principal photo-degradation pathway of nifedipine was modified and diverted in the presence of atenolol. To verify the same, a study was conducted employing two other β-blockers with similar structures to atenolol, and the same product was formed in relatively higher quantity therein also. The new product is postulated to be produced as a result of rearrangement of hydroxylamine

  6. Glutamine supplementation stimulates protein-synthetic and inhibits protein-degradative signaling pathways in skeletal muscle of diabetic rats.

    Directory of Open Access Journals (Sweden)

    Adriana C Lambertucci

    Full Text Available In this study, we investigated the effect of glutamine (Gln supplementation on the signaling pathways regulating protein synthesis and protein degradation in the skeletal muscle of rats with streptozotocin (STZ-induced diabetes. The expression levels of key regulatory proteins in the synthetic pathways (Akt, mTOR, GSK3 and 4E-BP1 and the degradation pathways (MuRF-1 and MAFbx were determined using real-time PCR and Western blotting in four groups of male Wistar rats; 1 control, non-supplemented with glutamine; 2 control, supplemented with glutamine; 3 diabetic, non-supplemented with glutamine; and 4 diabetic, supplemented with glutamine. Diabetes was induced by the intravenous injection of 65 mg/kg bw STZ in citrate buffer (pH 4.2; the non-diabetic controls received only citrate buffer. After 48 hours, diabetes was confirmed in the STZ-treated animals by the determination of blood glucose levels above 200 mg/dL. Starting on that day, a solution of 1 g/kg bw Gln in phosphate buffered saline (PBS was administered daily via gavage for 15 days to groups 2 and 4. Groups 1 and 3 received only PBS for the same duration. The rats were euthanized, and the soleus muscles were removed and homogenized in extraction buffer for the subsequent measurement of protein and mRNA levels. The results demonstrated a significant decrease in the muscle Gln content in the diabetic rats, and this level increased toward the control value in the diabetic rats receiving Gln. In addition, the diabetic rats exhibited a reduced mRNA expression of regulatory proteins in the protein synthesis pathway and increased expression of those associated with protein degradation. A reduction in the skeletal muscle mass in the diabetic rats was observed and was alleviated partially with Gln supplementation. The data suggest that glutamine supplementation is potentially useful for slowing the progression of muscle atrophy in patients with diabetes.

  7. Def defines a conserved nucleolar pathway that leads p53 to proteasome-independent degradation

    OpenAIRE

    Tao, Ting; Hui SHI; Guan, Yihong; Huang, Delai; Chen, Ye; Lane, David P; Chen, Jun; Peng, Jinrong

    2013-01-01

    p53 protein turnover through the ubiquitination pathway is a vital mechanism in the regulation of its transcriptional activity; however, little is known about p53 turnover through proteasome-independent pathway(s). The digestive organ expansion factor (Def) protein is essential for the development of digestive organs. In zebrafish, loss of function of def selectively upregulates the expression of p53 response genes, which raises a question as to what is the relationship between Def and p53. W...

  8. The regulatory role of reversible phosphorylation in the chlorophyll degradation pathway

    Science.gov (United States)

    Senescence represents the final stage of plant development and is characterized by several processes including the systematic degradation of the photosynthetic apparatus and chlorophyll molecules inside chloroplasts. Normally, chlorophyll is catabolized to colorless compounds through a series of enz...

  9. Combination of degradation pathways for naphthalene utilization in Rhodococcus sp. strain TFB

    OpenAIRE

    Tomás-Gallardo, Laura; Gómez-Álvarez, Helena; Santero, Eduardo; Floriano, Belén

    2013-01-01

    R hodococcus sp. strain TFB is a metabolic versatile bacterium able to grow on naphthalene as the only carbon and energy source. Applying proteomic, genetic and biochemical approaches, we propose in this paper that, at least, three coordinated but independently regulated set of genes are combined to degrade naphthalene in TFB. First, proteins involved in tetralin degradation are also induced by naphthalene and may carry out its conversion to salicylaldehyde. This is the only part of the napht...

  10. Alteration of Dynein Function Affects α-Synuclein Degradation via the Autophagosome-Lysosome Pathway

    OpenAIRE

    Da Li; Ji-Jun Shi; Cheng-Jie Mao; Sha Liu; Jian-Da Wang; Jing Chen; Fen Wang; Ya-Ping Yang; Wei-Dong Hu; Li-Fang Hu; Chun-Feng Liu

    2013-01-01

    Growing evidence suggests that dynein dysfunction may be implicated in the pathogenesis of neurodegeneration. It plays a central role in aggresome formation, the delivery of autophagosome to lysosome for fusion and degradation, which is a pro-survival mechanism essential for the bulk degradation of misfolded proteins and damaged organells. Previous studies reported that dynein dysfuntion was associated with aberrant aggregation of α-synuclein, which is a major component of inclusion bodies in...

  11. Novel Pathway of Salicylate Degradation by Streptomyces sp. Strain WA46

    OpenAIRE

    Ishiyama, Daisuke; Vujaklija, Dusica; Davies, Julian

    2004-01-01

    A novel salicylate-degrading Streptomyces sp., strain WA46, was identified by UV fluorescence on solid minimal medium containing salicylate; trace amounts of gentisate were detected by high-pressure liquid chromatography when strain WA46 was grown with salicylate. PCR amplification of WA46 DNA with degenerate primers for gentisate 1,2-dioxygenase (GDO) genes produced an amplicon of the expected size. Sequential PCR with nested GDO primers was then used to identify a salicylate degradation gen...

  12. Prediction of CL-20 chemical degradation pathways, theoretical and experimental evidence for dependence on competing modes of reaction

    Energy Technology Data Exchange (ETDEWEB)

    Qasim, Mohammad M.; Fredrickson, Herbert L.; Honea, P.; Furey, John; Leszczynski, Jerzy; Okovytyy, S.; Szecsody, Jim E.; Kholod, Y.

    2005-10-01

    Highest occupied and lowest unoccupied molecular orbital energies, formation energies, bond lengths and FTIR spectra all suggest competing CL-20 degradation mechanisms. This second of two studies investigates recalcitrant, toxic, aromatic CL-20 intermediates that absorb from 370 to 430 nm. Our earlier study (Struct. Chem., 15, 2004) revealed that these intermediates were formed at high OH- concentrations via the chemically preferred pathway of breaking the C-C bond between the two cyclopentanes, thereby eliminating nitro groups, forming conjugated π bonds, and resulting in a pyrazine three-ring aromatic intermediate. In attempting to find and make dominant a more benign CL-20 transformation pathway, this current research validates hydroxylation results from both studies and examines CL-20 transformations via photo-induced free radical reactions. This article discusses CL-20 competing modes of degradation revealed through: computational calculation; UV/VIS and SF spectroscopy following alkaline hydrolysis; and photochemical irradiation to degrade CL-20 and its byproducts at their respective wavelengths of maximum absorption.

  13. Prediction of CL-20 chemical degradation pathways, theoretical and experimental evidence for dependence on competing modes of reaction.

    Science.gov (United States)

    Qasim, M; Fredrickson, H; Honea, P; Furey, J; Leszczynski, J; Okovytyy, S; Szecsody, J; Kholod, Y

    2005-10-01

    Highest occupied and lowest unoccupied molecular orbital energies, formation energies, bond lengths and FTIR spectra all suggest competing CL-20 degradation mechanisms. This second of two studies investigates recalcitrant, toxic, aromatic CL-20 intermediates that absorb from 370 to 430 nm. Our earlier study (Struct. Chem., 15, 2004) revealed that these intermediates were formed at high OH(-) concentrations via the chemically preferred pathway of breaking the C-C bond between the two cyclopentanes, thereby eliminating nitro groups, forming conjugated pi bonds, and resulting in a pyrazine three-ring aromatic intermediate. In attempting to find and make dominant a more benign CL-20 transformation pathway, this current research validates hydroxylation results from both studies and examines CL-20 transformations via photo-induced free radical reactions. This article discusses CL-20 competing modes of degradation revealed through: computational calculation; UV/VIS and SF spectroscopy following alkaline hydrolysis; and photochemical irradiation to degrade CL-20 and its byproducts at their respective wavelengths of maximum absorption. PMID:16272046

  14. Mechanism and Reaction Pathways for Microcystin-LR Degradation through UV/H2O2 Treatment.

    Science.gov (United States)

    Liu, Yafeng; Ren, Jing; Wang, Xiangrong; Fan, Zhengqiu

    2016-01-01

    Microcystin-LR (MCLR) is the most common cyanotoxin in contaminated aquatic systems. MCLR inhibits protein phosphatases 1 and 2A, leading to liver damage and tumor formation. MCLR is relatively stable owing to its cyclic structures. The combined UV/H2O2 technology can degrade MCLR efficiently. The second-order rate constant of the reaction between MCLR and hydroxyl radical (·OH) is 2.79(±0.23)×1010 M-1 s-1 based on the competition kinetics model using nitrobenzene as reference compound. The probable degradation pathway was analyzed through liquid chromatography mass spectrometry. Results suggested that the major destruction pathways of MCLR were initiated by ·OH attack on the benzene ring and diene of the Adda side chain. The corresponding aldehyde or ketone peptide residues were formed through further oxidation. Another minor destruction pathway involved ·OH attack on the methoxy group of the Adda side chain, followed by complete removal of the methoxy group. The combined UV/H2O2 system is a promising technology for MCLR removal in contaminated aquatic systems.

  15. A novel role for ATM in regulating proteasome-mediated protein degradation through suppression of the ISG15 conjugation pathway.

    Directory of Open Access Journals (Sweden)

    Laurence M Wood

    Full Text Available Ataxia Telangiectasia (A-T is an inherited immunodeficiency disorder wherein mutation of the ATM kinase is responsible for the A-T pathogenesis. Although the precise role of ATM in A-T pathogenesis is still unclear, its function in responding to DNA damage has been well established. Here we demonstrate that in addition to its role in DNA repair, ATM also regulates proteasome-mediated protein turnover through suppression of the ISG15 pathway. This conclusion is based on three major pieces of evidence: First, we demonstrate that proteasome-mediated protein degradation is impaired in A-T cells. Second, we show that the reduced protein turnover is causally linked to the elevated expression of the ubiquitin-like protein ISG15 in A-T cells. Third, we show that expression of the ISG15 is elevated in A-T cells derived from various A-T patients, as well as in brain tissues derived from the ATM knockout mice and A-T patients, suggesting that ATM negatively regulates the ISG15 pathway. Our current findings suggest for the first time that proteasome-mediated protein degradation is impaired in A-T cells due to elevated expression of the ISG15 conjugation pathway, which could contribute to progressive neurodegeneration in A-T patients.

  16. Gamma radiolytic eradication of methoxychlor in aqueous media. The degradation pathways using HPLC and SPME-GC-MS

    Energy Technology Data Exchange (ETDEWEB)

    Butt, S.B.; Zafar, A. [PINSTECH, Nilore, Islamabad (Pakistan). Central Analytical Facility Div.; Riaz, M. [PINSTECH, Nilore, Islamabad (Pakistan). Chemistry Div.

    2013-08-01

    The gamma radiation-induced degradation of environmental pollutant methoxychlor in water was investigated. A {sup 60}Co gamma radiation source with a dose rate of 372 Gy h{sup -1} was used for gamma irradiation of 1 mg L{sup -1} and 10 mg L{sup -1} methoxychlor in water with a varied absorbed dose of 1-5 kGy. A single step clean up and pre-concentration procedure based on solid phase micro-extraction was optimized. The extent of radiolytic degradation was monitored by reversed phase HPLC-UV and GC-ECD. The trace and ultra trace level degradation products were identified using GC-MS-SPME by comparing their mass spectra with the NIST 98 m mass spectral library. Most of the generated products for 4 kGy dose are substituted chlorophenols. The reaction pathways of these substituted chlorophenols and benzophenone formation are also proposed. However, generated chlorophenols disappeared along with methoxychlor for an absorbed dose of 5 kGy. The attained degradation of methoxychlor is {proportional_to} 95% that reflects the potential use of ionization radiation for wastewater treatment. (orig.)

  17. Bis(2-chloroethoxy)methane degradation by TiO2 photocatalysis: Parameter and reaction pathway investigations

    International Nuclear Information System (INIS)

    Haloethers are widely used in industry, and the release of these species into the environment is of great concern because of their toxicity and carcinogenicity. The present study deals with the photocatalytic degradation of the haloether, bis(2-chloroethoxy)methane (BCEXM), in the presence of TiO2 particles and UV-A (λ = 365 nm) radiation. About 99.5% of BCEXM was degraded after UV irradiation for 16 h. Factors such as solution pH, TiO2 dosage, and the presence of anions were found to influence the degradation rate. To obtain a better understanding of the mechanistic details of this TiO2-assisted photodegradation of BCEXM with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. To the best of our knowledge, this is the first report on the degradation pathways of BCEXM. The first step in the destruction of BCEXM is thought to be abstraction of a hydrogen by ·OH to form a carbon-centered radical which then reacts with O2 to form a peroxyl radical. Peroxyl radicals react with one another and produce an alkoxy radical. The β-bond fragmentation of the alkoxy radical produces different intermediates.

  18. Bis(2-chloroethoxy)methane degradation by TiO{sub 2} photocatalysis: Parameter and reaction pathway investigations

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chiing-Chang [Department of Science Application and Dissemination, National Taichung University, Taichung 403, Taiwan (China); Wu, Ren-Jang; Yao, I.-Chun [Department of Applied Chemistry, Providence University, Taichung 433, Taiwan (China); Lu, Chung-Shin, E-mail: cslu6@ntcnc.edu.tw [Department of General Education, National Taichung Nursing College, No. 193, Sec. 1, San-Min Road, Taichung 403, Taiwan (China)

    2009-12-30

    Haloethers are widely used in industry, and the release of these species into the environment is of great concern because of their toxicity and carcinogenicity. The present study deals with the photocatalytic degradation of the haloether, bis(2-chloroethoxy)methane (BCEXM), in the presence of TiO{sub 2} particles and UV-A ({lambda} = 365 nm) radiation. About 99.5% of BCEXM was degraded after UV irradiation for 16 h. Factors such as solution pH, TiO{sub 2} dosage, and the presence of anions were found to influence the degradation rate. To obtain a better understanding of the mechanistic details of this TiO{sub 2}-assisted photodegradation of BCEXM with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. To the best of our knowledge, this is the first report on the degradation pathways of BCEXM. The first step in the destruction of BCEXM is thought to be abstraction of a hydrogen by {sup {center_dot}}OH to form a carbon-centered radical which then reacts with O{sub 2} to form a peroxyl radical. Peroxyl radicals react with one another and produce an alkoxy radical. The {beta}-bond fragmentation of the alkoxy radical produces different intermediates.

  19. Abiotic degradation of methyl parathion by manganese dioxide: Kinetics and transformation pathway.

    Science.gov (United States)

    Liao, Xiaoping; Zhang, Caixiang; Liu, Yuan; Luo, Yinwen; Wu, Sisi; Yuan, Songhu; Zhu, Zhenli

    2016-05-01

    Methyl parathion, a widely used insecticide around the world, has aroused gradually extensive concern of researchers due to its degradation product such as methyl paraoxon, with higher toxicity for mammals and more recalcitrant. Given the ubiquity of manganese dioxide (MnO2) in soils and aquatic sediments, the abiotic degradation of methyl parathion by α-MnO2 was investigated in batch experiments. It was found that methyl parathion was decomposed up to 90% by α-MnO2 in 30 h and the removal efficiency of methyl parathion depended strongly on the loading of α-MnO2 and pH value in the solution where the reactions followed pseudo-first-order model well. The coexisting metal ions (such as Ca(2+), Mg(2+) and Mn(2+)) weakened markedly the degradation of methyl parathion by α-MnO2. However, the effect of dissolved organic matter (HA-Na) on reaction rates presented two sides: to improve hydrolysis rate but deteriorate oxidation rate of methyl parathion. Based on the degradation products identified by gas chromatography-mass spectrometer (GC/MS) and liquid chromatography high-resolution mass spectrometer (LC/HRMS), both hydrolysis and oxidation processes were proposed to be two predominant reaction mechanisms contributing to methyl parathion degradation by α-MnO2. This study provided meaningful information to elucidate the abiotic dissipation of methyl parathion by manganese oxide minerals in the environment. PMID:26891361

  20. Degradation of the Separase-cleaved Rec8, a Meiotic Cohesin Subunit, by the N-end Rule Pathway.

    Science.gov (United States)

    Liu, Yu-Jiao; Liu, Chao; Chang, ZeNan; Wadas, Brandon; Brower, Christopher S; Song, Zhen-Hua; Xu, Zhi-Liang; Shang, Yong-Liang; Liu, Wei-Xiao; Wang, Li-Na; Dong, Wen; Varshavsky, Alexander; Hu, Rong-Gui; Li, Wei

    2016-04-01

    The Ate1 arginyltransferase (R-transferase) is a component of the N-end rule pathway, which recognizes proteins containing N-terminal degradation signals called N-degrons, polyubiquitylates these proteins, and thereby causes their degradation by the proteasome. Ate1 arginylates N-terminal Asp, Glu, or (oxidized) Cys. The resulting N-terminal Arg is recognized by ubiquitin ligases of the N-end rule pathway. In the yeastSaccharomyces cerevisiae, the separase-mediated cleavage of the Scc1/Rad21/Mcd1 cohesin subunit generates a C-terminal fragment that bears N-terminal Arg and is destroyed by the N-end rule pathway without a requirement for arginylation. In contrast, the separase-mediated cleavage of Rec8, the mammalian meiotic cohesin subunit, yields a fragment bearing N-terminal Glu, a substrate of the Ate1 R-transferase. Here we constructed and used a germ cell-confinedAte1(-/-)mouse strain to analyze the separase-generated C-terminal fragment of Rec8. We show that this fragment is a short-lived N-end rule substrate, that its degradation requires N-terminal arginylation, and that maleAte1(-/-)mice are nearly infertile, due to massive apoptotic death ofAte1(-/-)spermatocytes during the metaphase of meiosis I. These effects ofAte1ablation are inferred to be caused, at least in part, by the failure to destroy the C-terminal fragment of Rec8 in the absence of N-terminal arginylation. PMID:26858254

  1. HPLC Determination of 5-Hydroxymethylfurfural and Ecdysterone in Granules of Radix Achyranthis Bidentatae%高效液相色谱法测定牛膝颗粒中5-羟甲基糠醛和蜕皮甾酮的含量

    Institute of Scientific and Technical Information of China (English)

    赵变; 郭红云; 常珍珍; 孙祥德

    2012-01-01

    提出了高效液相色谱法同时测定牛膝配方颗粒中5-羟甲基糠醛和蜕皮甾酮的含量的方法。采用SHIMADZU shim-packVP—ODS(4.6mm×250mm,4.6μm)柱;用两种不同配比的乙腈和水混合溶液作为流动相,梯度洗脱;检测波长为279nm(5-羟甲基糠醛)和245nm(蜕皮甾酮)。5-羟甲基糠醛和蜕皮甾酮的质量浓度分别在0.390-100mg·L-1和3.125~100mg·L-1范围内与峰面积呈线性关系,方法的检出限(3S/N)分别为1.95,2.01ng。5-羟甲基糠醛和蜕皮甾酮的平均回收率分别为99.7%,99.1%;相对标准偏差(n=5)分别为0.80%,0.67%。%HPLC was applied to the simultaneous determination of 5-hydroxymethylfurfural and ecdysterone in granules of radix achyranthis bientatae for making up prescriptions. SHIMADZU shira pack VP-ODS column (4. 6 nm×250 mm,4.6μm) was used for separation. Mixtures containing acetonitrile and water mixed in different ratio were used as the mobile phase in gradient elution. UV-detection at the wavelengths of 279 nm (for 5-hydroxymethylfurfural) and 245 nm (for ecdysterone) was adopted in the determination. Linear relationships between values of peak area and mass concentration of 5-hydroxymethylfurfural and ecdysterone were obtained in the ranges of 0. 390--100 mg·L-1 and 3. 125-100 mg·L-1 , with detection limits (3S/N) of 1.95 ng and 2.01 ng respectively. Results of recovery and precision found were: values of average recovery of 99. 7% for 5-hydroxymethylfurfural and 99.1% for ecdysteronen with values of RSD's (n = 5) 0.80% and 0.67% respectively.

  2. Elucidating the Pseudomonas aeruginosa Fatty Acid Degradation Pathway: Identification of Additional Fatty Acyl-CoA Synthetase Homologues

    OpenAIRE

    Zarzycki-Siek, Jan; Norris, Michael H.; Kang, Yun (Kenneth); Sun, Zhenxin; Bluhm, Andrew P.; McMillan, Ian A.; Hoang, Tung T.

    2013-01-01

    The fatty acid (FA) degradation pathway of Pseudomonas aeruginosa, an opportunistic pathogen, was recently shown to be involved in nutrient acquisition during BALB/c mouse lung infection model. The source of FA in the lung is believed to be phosphatidylcholine, the major component of lung surfactant. Previous research indicated that P. aeruginosa has more than two fatty acyl-CoA synthetase genes (fadD; PA3299 and PA3300), which are responsible for activation of FAs using ATP and coenzyme A. T...

  3. Microbial degradation pathways of the herbicide dichlobenil in soils with different history of dichlobenil-exposure

    International Nuclear Information System (INIS)

    This is the first detailed study of metabolite production during degradation of the herbicide 2,6-dichlorobenzonitrile (dichlobenil). Degradation of dichlobenil and three potential metabolites: 2,6-dichlorobenzamide (BAM), 2,6-dichlorobenzoic acid (2,6-DCBA) and ortho-chlorobenzamide (OBAM) was studied in soils either previously exposed or not exposed to dichlobenil using a newly developed HPLC method. Dichlobenil was degraded in all four soils; BAM and 2,6-DCBA were only degraded in soils previously exposed to dichlobenil (100% within 35-56 days and 85-100% in 56 days, respectively), and OBAM in all four soils (25-33% removal in 48 days). BAM produced from dichlobenil was either hydrolyzed to 2,6-DCBA or dechlorinated to OBAM, which was further hydrolyzed to ortho-chlorobenzoic acid. BAM was rapidly mineralized in previously exposed soils only. All potential metabolites and the finding that BAM was a dead-end metabolite of dichlobenil in soils not previously exposed to dichlobenil needs to be included in risk assessments of the use of dichlobenil. - BAM produced from dichlobenil was either hydrolyzed to 2,6-DCBA or dechlorinated to OBAM, which was further hydrolyzed to ortho-chlorobenzoic acid

  4. UV photolysis of diclofenac in water; kinetics, degradation pathway and environmental aspects.

    Science.gov (United States)

    Kovacic, Marin; Juretic Perisic, Daria; Biosic, Martina; Kusic, Hrvoje; Babic, Sandra; Loncaric Bozic, Ana

    2016-08-01

    In this study, the photolysis behavior of commonly used anti-inflammatory drug diclofenac (DCF) was investigated using UV-C and UV-A irradiation. In that purpose, DCF conversion kinetics, mineralization of organic content, biodegradability, and toxicity were monitored and compared. The results showed different kinetics of DCF conversion regarding the type of UV source applied. However, in both cases, the mineralization extent reached upon complete DCF conversion is rather low (≤10 %), suggesting that the majority of DCF was transformed into by-products. Formation/degradation of main degradation by-products was monitored using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS), whereas different profiles were obtained by UV-C and UV-A photolysis. The results of bioassays revealed that biodegradability of DCF solutions remained low through the applied treatments. The toxicity of irradiated DCF solutions was evaluated using Vibrio fischeri. A significant reduction of toxicity, especially in the case of UV-A radiation, was observed upon complete degradation of DCF. In addition to toxicity reduction, calculated Log K OW values of DCF degradation by-products indicate their low potential for bioaccumulation (Log K OW ≤ 3) in comparison to the parent substance.

  5. Understanding the degradation pathway of the pesticide, chlorpyrifos by noble metal nanoparticles.

    Science.gov (United States)

    Bootharaju, M S; Pradeep, T

    2012-02-01

    Application of nanoparticles (NPs) in environmental remediation such as water purification requires a detailed understanding of the mechanistic aspects of the interaction between the species involved. Here, an attempt was made to understand the chemistry of noble metal nanoparticle-pesticide interaction, as these nanosystems are being used extensively for water purification. Our model pesticide, chlorpyrifos (CP), belonging to the organophosphorothioate group, is shown to decompose to 3,5,6-trichloro-2-pyridinol (TCP) and diethyl thiophosphate at room temperature over Ag and Au NPs, in supported and unsupported forms. The degradation products were characterized by absorption spectroscopy and electrospray ionization mass spectrometry (ESI MS). These were further confirmed by ESI tandem mass spectrometry. The interaction of CP with NP surfaces was investigated using transmission electron microscopy, energy dispersive analysis of X-rays, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XPS reveals no change in the oxidation state of silver after the degradation of CP. It is proposed that the degradation of CP proceeds through the formation of AgNP-S surface complex, which is confirmed by Raman spectroscopy. In this complex, the P-O bond cleaves to yield a stable aromatic species, TCP. The rate of degradation of CP increases with increase of temperature and pH. Complete degradation of 10 mL of 2 ppm CP solution is achieved in 3 h using 100 mg of supported Ag@citrate NPs on neutral alumina at room temperature at a loading of ∼0.5 wt %. The effect of alumina and monolayer protection of NPs on the degradation of CP is also investigated. The rate of degradation of CP by Ag NPs is greater than that of Au NPs. The results have implications to the application of noble metal NPs for drinking water purification, as pesticide contamination is prevalent in many parts of the world. Study shows that supported Ag and Au NPs may be employed in sustainable

  6. Determination of the hydrothermal degradation products of D-(U-14C) glucose and D-(U-14C) fructose by TLC

    International Nuclear Information System (INIS)

    Hydrothermal degradation was examined using D-(U-14C) glucose and D-(U-14C) fructose. By thin layer chromatography with methylene chloride, tetrahydrofuran (THF), acetic acid - 60:20:20 as a mobile phase; it was possible to separate and identify the carbohydrates and their reaction products, glyceraldehyde, dihydroxyacetone, methylglyoxal, glycolaldehyde, 5-hydroxymethylfurfural and furfural. Up to 99% of the initial activity was determined by scintillation counting of the TL-chromatograms. A reaction scheme for the hydrothermal degradation of glucose and fructose was obtained from these results. (author)

  7. Stability of 6:2 fluorotelomer sulfonate in advanced oxidation processes: degradation kinetics and pathway.

    Science.gov (United States)

    Yang, Xiaoling; Huang, Jun; Zhang, Kunlun; Yu, Gang; Deng, Shubo; Wang, Bin

    2014-03-01

    Perfluorooctane sulfonate (PFOS), a widely used mist suppressant in hard chrome electroplating industry, has been listed in the Stockholm Convention for global ban. 6:2 Fluorotelomer sulfonate (6:2 FTS) acid and salts have been adopted as alternative products in the market, but no data about their abiotic degradation has been reported. In the present study, the degradability of 6:2 FTS potassium salt (6:2 FTS-K) was evaluated under various advanced oxidation processes, including ultraviolet (UV) irradiation, UV with hydrogen peroxide (H2O2), alkaline ozonation (O3, pH = 11), peroxone (O3/H2O2), and Fenton reagent oxidation (Fe(2+)/H2O2). UV/H2O2 was found to be the most effective approach, where the degradation of 6:2 FTS-K followed the pseudo-first-order kinetics. The intermediates were mainly shorter chain perfluoroalkyl carboxylic acid (C7 to C2), while sulfate (SO4 (2-)) and fluoride (F(-)) were found to be the final products. The high yields of SO4 (2-) and F(-) indicate that 6:2 FTS-K can be nearly completely desulfonated and defluorinated under UV/H2O2 condition. The degradation should firstly begin with the substitution of hydrogen atom by hydroxyl radicals, followed by desulfonation, carboxylation, and sequential "flake off" of CF2 unit. Compared with PFOS which is inert in most advanced oxidation processes, 6:2 FTS-K is more degradable as the alternative.

  8. 13C Tracers for Glucose Degrading Pathway Discrimination in Gluconobacter oxydans 621H

    Directory of Open Access Journals (Sweden)

    Steffen Ostermann

    2015-09-01

    Full Text Available Gluconobacter oxydans 621H is used as an industrial production organism due to its exceptional ability to incompletely oxidize a great variety of carbohydrates in the periplasm. With glucose as the carbon source, up to 90% of the initial concentration is oxidized periplasmatically to gluconate and ketogluconates. Growth on glucose is biphasic and intracellular sugar catabolism proceeds via the Entner–Doudoroff pathway (EDP and the pentose phosphate pathway (PPP. Here we studied the in vivo contributions of the two pathways to glucose catabolism on a microtiter scale. In our approach we applied specifically 13C labeled glucose, whereby a labeling pattern in alanine was generated intracellularly. This method revealed a dynamic growth phase-dependent pathway activity with increased activity of EDP in the first and PPP in the second growth phase, respectively. Evidence for a growth phase-independent decarboxylation-carboxylation cycle around the pyruvate node was obtained from 13C fragmentation patterns of alanine. For the first time, down-scaled microtiter plate cultivation together with 13C-labeled substrate was applied for G. oxydans to elucidate pathway operation, exhibiting reasonable labeling costs and allowing for sufficient replicate experiments.

  9. CO2-高温液态水体系下果糖分解制备5-羟甲基糠醛的研究%Study on the reaction of fructose dehydration to 5-hydroxymethylfurfural by CO2-high temperature liquid water system

    Institute of Scientific and Technical Information of China (English)

    黎演明; 李秉正; 吴学众; 黄日波

    2012-01-01

    5-Hydroxymethylfurfural (5-HMF)is a kind of important chemical intermediates which has wide application value and market prospect. The initial CO2 pressure, reaction temperature and initial fructose concentration were discussed for the influence on the reaction of fructose dehydration to 5-hydroxymethylfurfural under CO2-high temperature liquid water system. The results indicated that CO2-high temperature liquid water catalytic system exhibited high catalyst activity on fructose dehydration to 5-hydroxymethylfurfural, good recovery of 5-HMF was obtained even the initial fructose concentration up to 10%. Yield of 5-HMF and selectivity generation of 5-HMF ware respectively 54.3% and 57.7%,under the condition of 5 MPa CO2 pressure, 160 ℃, and 100 minutes in 3% initial fructose concentration, and catalyst activity was 2-3 times comparing to high temperature liquid water which does no exist C02. The reaction of fructose dehydration to 5-hydroxymethylfurfural was remarkably influenced by CO2 pressure. With the increase of CO2 pressure, the yield of 5-HMF increased, but the selectivity generation to 5-HMF decreased.%5-羟甲基糠醛(5-HMF)是一种重要的化工中间体,具有非常广泛的应用价值和市场前景.在CO2-高温液态水体系下,探讨了二氧化碳初始压力、反应温度以及果糖初始浓度等因素对果糖制备5-HMF的影响.结果表明,CO2-高温液态水催化体系对果糖脱水分解制备5-HMF具有较高的催化活性,在果糖初始浓度高达10%时也可获得较好的5-HMF收率.在果糖浓度为3%,CO2压力为5.0 MPa,160℃的条件下反应100 min,5-HMF的收率为54.3%,反应生成5-HMF的选择性高达57.7%,催化活性为无CO2的高温液态水的2~3倍.CO2压力对果糖分解制备5-HMF有重要影响,随着体系中CO2压力的增加,5-HMF的收率也逐渐增加,但生成5-HMF的选择性有所下降.

  10. Pathways of nitrobenzene degradation in horizontal subsurface flow constructed wetlands: Effect of intermittent aeration and glucose addition.

    Science.gov (United States)

    Kirui, Wesley K; Wu, Shubiao; Kizito, Simon; Carvalho, Pedro N; Dong, Renjie

    2016-01-15

    Intermittent aeration and addition of glucose were applied to horizontal subsurface flow constructed wetlands in order to investigate the effect on pathways of nitrobenzene (NB) degradation and interactions with microbial nitrogen and sulphur transformations. The experiment was carried out in three phases A, B and C consisting of different NB loading and glucose dosing. For each phase, the effect of aeration was assessed by intermittently aerating one wetland and leaving one unaerated. Regardless of whether or not the wetland was aerated, at an influent NB concentration of 140 mg/L, both wetlands significantly reduced NB to less than 2 mg/L, a reduction efficiency of 98%. However, once the influent NB concentration was increased to 280 mg/L, the aerated wetland had a higher removal performance 82% compared to that of the unaerated wetland 71%. Addition of glucose further intensified the NB removal to 95% in the aerated wetlands and 92% in the unaerated. Aeration of wetlands enhanced NB degradation, but also resulted in higher NB volatilization of 6 mg m(-2) d(-1). The detected high concentration of sulphide 20-60 mg/L in the unaerated wetland gave a strong indication that NB may act as an electron donor to sulphate-reducing bacteria, but this should be further investigated. Aeration positively improved NB removal in constructed wetlands, but resulted in higher NB volatilization. Glucose addition induced co-metabolism to enhance NB degradation. PMID:26468606

  11. Pathways of nitrobenzene degradation in horizontal subsurface flow constructed wetlands: Effect of intermittent aeration and glucose addition.

    Science.gov (United States)

    Kirui, Wesley K; Wu, Shubiao; Kizito, Simon; Carvalho, Pedro N; Dong, Renjie

    2016-01-15

    Intermittent aeration and addition of glucose were applied to horizontal subsurface flow constructed wetlands in order to investigate the effect on pathways of nitrobenzene (NB) degradation and interactions with microbial nitrogen and sulphur transformations. The experiment was carried out in three phases A, B and C consisting of different NB loading and glucose dosing. For each phase, the effect of aeration was assessed by intermittently aerating one wetland and leaving one unaerated. Regardless of whether or not the wetland was aerated, at an influent NB concentration of 140 mg/L, both wetlands significantly reduced NB to less than 2 mg/L, a reduction efficiency of 98%. However, once the influent NB concentration was increased to 280 mg/L, the aerated wetland had a higher removal performance 82% compared to that of the unaerated wetland 71%. Addition of glucose further intensified the NB removal to 95% in the aerated wetlands and 92% in the unaerated. Aeration of wetlands enhanced NB degradation, but also resulted in higher NB volatilization of 6 mg m(-2) d(-1). The detected high concentration of sulphide 20-60 mg/L in the unaerated wetland gave a strong indication that NB may act as an electron donor to sulphate-reducing bacteria, but this should be further investigated. Aeration positively improved NB removal in constructed wetlands, but resulted in higher NB volatilization. Glucose addition induced co-metabolism to enhance NB degradation.

  12. Electrochemical degradation of sulfonamides at BDD electrode: Kinetics, reaction pathway and eco-toxicity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Fabiańska, Aleksandra; Białk-Bielińska, Anna; Stepnowski, Piotr [Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-952 Gdansk (Poland); Stolte, Stefan [Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-952 Gdansk (Poland); UFT-Centre of Environmental Research and Sustainable Technology, University of Bremen, Leobener Straße UFT, D-28359 Bremen (Germany); Siedlecka, Ewa Maria, E-mail: ewa.siedlecka@ug.edu.pl [Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-952 Gdansk (Poland)

    2014-09-15

    Highlights: • SNs were electrochemically oxidized at BDD in one compartment reactor. • The efficiency of SN degradation was the highest in effluents from municipal WWTP. • The electro-degradation SNs based on oxidation but reduction was also possible. • Electrochemical oxidation of SNs led in some cases to mixtures toxic to L. minor. - Abstract: The investigation dealt with electrochemical oxidation of five sulfonamides (SNs): sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMN) and sulfadimethoxine (SDM) in aqueous solution at boron-doped diamond (BDD) electrode. All studied sulfonamides were degraded according to a pseudo first order kinetics. The structure of SNs had no significant effect on the values of pseudo first order rate constants. Increased degradation efficiency was observed in higher temperature and in acidic pH. Due to the presence of chlorine and nitrate SNs were more effectively oxidized from municipal wastewater treatment plant (WWTP) effluents than from pure supporting electrolyte Na{sub 2}SO{sub 4}. The intermediates identified by LC–MS and GC–MS analysis suggested that the hydroxyl radicals attack mainly the S-N bond, but also the aromatic ring systems (aniline, pyrimidine or triazole) of SNs. Finally, the toxicity of the SNs solutions and effluents after electrochemical treatment was assessed through the measurement of growth inhibition of green algae (Scenedesmus vacualatus) and duckweed (Lemna minor). Toxicity of SMR, STZ, SMN solutions before and after electrochemical oxidation and SDM solution after the process in L. minor test was observed. No significant toxicity of studied SNs was observed in algae test.

  13. Electrochemical treatment of trypan blue synthetic wastewater and its degradation pathway

    OpenAIRE

    ANANTHA N. SUBBA RAO; ENKATESHA T. VENKATARANGAIAH

    2013-01-01

    The trypan blue (TB) dye synthetic wastewater was treated in presence of chloride ions by electrochemical method. The effect of current density, pH, initial concentration of dye and supporting electrolyte on color and COD removal were investigated. The UV-Vis ab­sorption intensity, chemical oxygen demand (COD), cyclic voltammetry (CV), Fourier transform- infrared spectroscopy (FT-IR), gas chromatography – mass spectrometry (GC-MS) analysis were conducted to investigate the kinetics and degrad...

  14. New Biochemical Pathway for Biphenyl Degradation in Plants: Structural, Mechanistic and Biotechnological Aspects

    Energy Technology Data Exchange (ETDEWEB)

    Pacios, L. F.; Campos, V. M.; Merino, I.; Gomez, L.

    2009-07-01

    Polychlorinated biphenyls (PVBs) and other structurally-related xenobiotics are amongst the most relevant organic pollutants known today. while some bacterial species can metabolize PCBs, with varying efficiency, no catabolic pathways have yet been described in plants. This is so despite the great potential of (at least some) plant species for soil and groundwater decontamination, a technology known as phyto remediation. (Author)

  15. Elucidating the Pseudomonas aeruginosa fatty acid degradation pathway: identification of additional fatty acyl-CoA synthetase homologues.

    Directory of Open Access Journals (Sweden)

    Jan Zarzycki-Siek

    Full Text Available The fatty acid (FA degradation pathway of Pseudomonas aeruginosa, an opportunistic pathogen, was recently shown to be involved in nutrient acquisition during BALB/c mouse lung infection model. The source of FA in the lung is believed to be phosphatidylcholine, the major component of lung surfactant. Previous research indicated that P. aeruginosa has more than two fatty acyl-CoA synthetase genes (fadD; PA3299 and PA3300, which are responsible for activation of FAs using ATP and coenzyme A. Through a bioinformatics approach, 11 candidate genes were identified by their homology to the Escherichia coli FadD in the present study. Four new homologues of fadD (PA1617, PA2893, PA3860, and PA3924 were functionally confirmed by their ability to complement the E. coli fadD mutant on FA-containing media. Growth phenotypes of 17 combinatorial fadD mutants on different FAs, as sole carbon sources, indicated that the four new fadD homologues are involved in FA degradation, bringing the total number of P. aeruginosa fadD genes to six. Of the four new homologues, fadD4 (PA1617 contributed the most to the degradation of different chain length FAs. Growth patterns of various fadD mutants on plant-based perfumery substances, citronellic and geranic acids, as sole carbon and energy sources indicated that fadD4 is also involved in the degradation of these plant-derived compounds. A decrease in fitness of the sextuple fadD mutant, relative to the ΔfadD1D2 mutant, was only observed during BALB/c mouse lung infection at 24 h.

  16. Elucidating the Pseudomonas aeruginosa fatty acid degradation pathway: identification of additional fatty acyl-CoA synthetase homologues.

    Science.gov (United States)

    Zarzycki-Siek, Jan; Norris, Michael H; Kang, Yun; Sun, Zhenxin; Bluhm, Andrew P; McMillan, Ian A; Hoang, Tung T

    2013-01-01

    The fatty acid (FA) degradation pathway of Pseudomonas aeruginosa, an opportunistic pathogen, was recently shown to be involved in nutrient acquisition during BALB/c mouse lung infection model. The source of FA in the lung is believed to be phosphatidylcholine, the major component of lung surfactant. Previous research indicated that P. aeruginosa has more than two fatty acyl-CoA synthetase genes (fadD; PA3299 and PA3300), which are responsible for activation of FAs using ATP and coenzyme A. Through a bioinformatics approach, 11 candidate genes were identified by their homology to the Escherichia coli FadD in the present study. Four new homologues of fadD (PA1617, PA2893, PA3860, and PA3924) were functionally confirmed by their ability to complement the E. coli fadD mutant on FA-containing media. Growth phenotypes of 17 combinatorial fadD mutants on different FAs, as sole carbon sources, indicated that the four new fadD homologues are involved in FA degradation, bringing the total number of P. aeruginosa fadD genes to six. Of the four new homologues, fadD4 (PA1617) contributed the most to the degradation of different chain length FAs. Growth patterns of various fadD mutants on plant-based perfumery substances, citronellic and geranic acids, as sole carbon and energy sources indicated that fadD4 is also involved in the degradation of these plant-derived compounds. A decrease in fitness of the sextuple fadD mutant, relative to the ΔfadD1D2 mutant, was only observed during BALB/c mouse lung infection at 24 h. PMID:23737986

  17. Insulin-degrading enzyme secretion from astrocytes is mediated by an autophagy-based unconventional secretory pathway in Alzheimer disease.

    Science.gov (United States)

    Son, Sung Min; Cha, Moon-Yong; Choi, Heesun; Kang, Seokjo; Choi, Hyunjung; Lee, Myung-Shik; Park, Sun Ah; Mook-Jung, Inhee

    2016-05-01

    The secretion of proteins that lack a signal sequence to the extracellular milieu is regulated by their transition through the unconventional secretory pathway. IDE (insulin-degrading enzyme) is one of the major proteases of amyloid beta peptide (Aβ), a presumed causative molecule in Alzheimer disease (AD) pathogenesis. IDE acts in the extracellular space despite having no signal sequence, but the underlying mechanism of IDE secretion extracellularly is still unknown. In this study, we found that IDE levels were reduced in the cerebrospinal fluid (CSF) of patients with AD and in pathology-bearing AD-model mice. Since astrocytes are the main cell types for IDE secretion, astrocytes were treated with Aβ. Aβ increased the IDE levels in a time- and concentration-dependent manner. Moreover, IDE secretion was associated with an autophagy-based unconventional secretory pathway, and depended on the activity of RAB8A and GORASP (Golgi reassembly stacking protein). Finally, mice with global haploinsufficiency of an essential autophagy gene, showed decreased IDE levels in the CSF in response to an intracerebroventricular (i.c.v.) injection of Aβ. These results indicate that IDE is secreted from astrocytes through an autophagy-based unconventional secretory pathway in AD conditions, and that the regulation of autophagy is a potential therapeutic target in addressing Aβ pathology.

  18. Population sinks resulting from degraded habitats of an obligate life-history pathway.

    Science.gov (United States)

    Hickford, Michael J H; Schiel, David R

    2011-05-01

    Many species traverse multiple habitats across ecosystems to complete their life histories. Degradation of critical, life stage-specific habitats can therefore lead to population bottlenecks and demographic deficits in sub-populations. The riparian zone of waterways is one of the most impacted areas of the coastal zone because of urbanisation, deforestation, farming and livestock grazing. We hypothesised that sink populations can result from alterations of habitats critical to the early life stages of diadromous fish that use this zone, and tested this with field-based sampling and experiments. We found that for Galaxias maculatus, one of the most widely distributed fishes of the southern hemisphere, obligate riparian spawning habitat was very limited and highly vulnerable to disturbance across 14 rivers in New Zealand. Eggs were laid only during spring tides, in the highest tidally influenced vegetation of waterways. Egg survival increased to >90% when laid in three riparian plant species and where stem densities were great enough to prevent desiccation, compared to no survival where vegetation was comprised of other species or was less dense. Experimental exclusion of livestock, one of the major sources of riparian degradation in rural waterways, resulted in quick regeneration, a tenfold increase in egg laying by fish and a threefold increase in survival, compared to adjacent controls. Overall, there was an inverse relationship between river size and egg production. Some of the largest rivers had little or no spawning habitat and very little egg production, effectively becoming sink populations despite supporting large adult populations, whereas some of the smallest pristine streams produced millions of eggs. We demonstrate that even a wide-ranging species with many robust adult populations can be compromised if a stage-specific habitat required to complete a life history is degraded by localised or more diffuse impacts. PMID:21076966

  19. Regulation of protein degradation pathways by amino acids and insulin in skeletal muscle of neonatal pigs

    Institute of Scientific and Technical Information of China (English)

    Agus Suryawan; Teresa ADavis

    2014-01-01

    Background:The rapid gain in lean mass in neonates requires greater rates of protein synthesis than degradation. We previously delineated the molecular mechanisms by which insulin and amino acids, especially leucine, modulate skeletal muscle protein synthesis and how this changes with development. In the current study, we identified mechanisms involved in protein degradation regulation. In experiment 1, 6-and 26-d-old pigs were studied during 1) euinsulinemic-euglycemic-euaminoacidemic, 2) euinsulinemic-euglycemic-hyperaminoacidemic, and 3) hyperinsulinemic-euglycemic-euaminoacidemic clamps for 2 h. In experiment 2, 5-d-old pigs were studied during 1) euinsulinemic-euglycemic-euaminoacidemic-euleucinemic, 2) euinsulinemic-euglycemic-hypoaminoacidemic-hyperleucinemic, and 3) euinsulinemic-euglycemic-euaminoacidemic-hyperleucinemic clamps for 24 h. We determined in muscle indices of ubiquitin-proteasome, i.e., atrogin-1 (MAFbx) and muscle RING-finger protein-1 (MuRF1) and autophagy-lysosome systems, i.e., unc51-like kinase 1 (UKL1), microtubule-associated protein light chain 3 (LC3), and lysosomal-associated membrane protein 2 (Lamp-2). For comparison, we measured ribosomal protein S6 (rpS6) and eukaryotic initiation factor 4E (eIF4E) activation, components of translation initiation. Results:Abundance of atrogin-1, but not MuRF1, was greater in 26-than 6-d-old pigs and was not affected by insulin, amino acids, or leucine. Abundance of ULK1 and LC3 was higher in younger pigs and not affected by treatment. The LC3-II/LC3-I ratio was reduced and ULK1 phosphorylation increased by insulin, amino acids, and leucine. These responses were more profound in younger pigs. Abundance of Lamp-2 was not affected by treatment or development. Abundance of eIF4E, but not rpS6, was higher in 6-than 26-d-old-pigs but unaffected by treatment. Phosphorylation of eIF4E was not affected by treatment, however, insulin, amino acids, and leucine stimulated rpS6 phosphorylation, and the

  20. Carnosic acid promotes degradation of the androgen receptor and is regulated by the unfolded protein response pathway in vitro and in vivo.

    Science.gov (United States)

    Petiwala, Sakina M; Li, Gongbo; Bosland, Maarten C; Lantvit, Daniel D; Petukhov, Pavel A; Johnson, Jeremy J

    2016-08-01

    Androgen deprivation therapy in prostate cancer is extremely effective; however, due to the continuous expression and/or mutagenesis of androgen receptor (AR), the resistance to antihormonal therapy is a natural progression. Consequently, targeting the AR for degradation offers an alternate approach to overcome this resistance in prostate cancer. In this study, we demonstrate that carnosic acid, a benzenediol diterpene, binds the ligand-binding domain of the AR and degrades the AR via endoplasmic reticulum (ER) stress-mediated proteasomal degradative pathway. In vitro, carnosic acid treatment induced degradation of AR and decreased expression of prostate-specific antigen in human prostate cancer cell lines LNCaP and 22Rv1. Carnosic acid also promoted the expression of ER proteins including BiP and CHOP in a dose-dependent manner. Downregulation of CHOP by small interfering RNA somewhat restored expression of AR suggesting that AR degradation is dependent on ER stress pathway. Future studies will need to evaluate other aspects of the unfolded protein response pathway to characterize the regulation of AR degradation. Furthermore, cotreating cells individually with carnosic acid and proteasome inhibitor (MG-132) and carnosic acid and an ER stress modulator (salubrinal) restored protein levels of AR, suggesting that AR degradation is mediated by ER stress-dependent proteasomal degradation pathway. Degradation of AR and induction of CHOP protein were also evident in vivo along with a 53% reduction in growth of xenograft prostate cancer tumors. In addition, carnosic acid-induced ER stress in prostate cancer cells but not in normal prostate epithelial cells procured from patient biopsies. In conclusion, these data suggest that molecules such as carnosic acid could be further evaluated and optimized as a potential therapeutic alternative to target AR in prostate cancer. PMID:27267997

  1. Bioremediation of soil polluted with crude oil and its derivatives: Microorganisms, degradation pathways, technologies

    Directory of Open Access Journals (Sweden)

    Beškoski Vladimir P.

    2012-01-01

    Full Text Available The contamination of soil and water with petroleum and its products occurs due to accidental spills during exploitation, transport, processing, storing and use. In order to control the environmental risks caused by petroleum products a variety of techniques based on physical, chemical and biological methods have been used. Biological methods are considered to have a comparative advantage as cost effective and environmentally friendly technologies. Bioremediation, defined as the use of biological systems to destroy and reduce the concentrations of hazardous waste from contaminated sites, is an evolving technology for the removal and degradation of petroleum hydrocarbons as well as industrial solvents, phenols and pesticides. Microorganisms are the main bioremediation agents due to their diverse metabolic capacities. In order to enhance the rate of pollutant degradation the technology optimizes the conditions for the growth of microorganisms present in soil by aeration, nutrient addition and, if necessary, by adding separately prepared microorganisms cultures. The other factors that influence the efficiency of process are temperature, humidity, presence of surfactants, soil pH, mineral composition, content of organic substance of soil as well as type and concentration of contaminant. This paper presents a review of our ex situ bioremediation procedures successfully implemented on the industrial level. This technology was used for treatment of soils contaminated by crude oil and its derivatives originated from refinery as well as soils polluted with oil fuel and transformer oil.

  2. Electrochemical degradation of sulfonamides at BDD electrode: kinetics, reaction pathway and eco-toxicity evaluation.

    Science.gov (United States)

    Fabiańska, Aleksandra; Białk-Bielińska, Anna; Stepnowski, Piotr; Stolte, Stefan; Siedlecka, Ewa Maria

    2014-09-15

    The investigation dealt with electrochemical oxidation of five sulfonamides (SNs): sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMN) and sulfadimethoxine (SDM) in aqueous solution at boron-doped diamond (BDD) electrode. All studied sulfonamides were degraded according to a pseudo first order kinetics. The structure of SNs had no significant effect on the values of pseudo first order rate constants. Increased degradation efficiency was observed in higher temperature and in acidic pH. Due to the presence of chlorine and nitrate SNs were more effectively oxidized from municipal wastewater treatment plant (WWTP) effluents than from pure supporting electrolyte Na2SO4. The intermediates identified by LC-MS and GC-MS analysis suggested that the hydroxyl radicals attack mainly the SN bond, but also the aromatic ring systems (aniline, pyrimidine or triazole) of SNs. Finally, the toxicity of the SNs solutions and effluents after electrochemical treatment was assessed through the measurement of growth inhibition of green algae (Scenedesmus vacualatus) and duckweed (Lemna minor). Toxicity of SMR, STZ, SMN solutions before and after electrochemical oxidation and SDM solution after the process in L. minor test was observed. No significant toxicity of studied SNs was observed in algae test. PMID:25215656

  3. Lipid rafts participate in aberrant degradative autophagic-lysosomal pathway of amyloid-beta peptide in Alzheimer’s disease

    Institute of Scientific and Technical Information of China (English)

    Xin Zhou; Chun Yang; Yufeng Liu; Peng Li; Huiying Yang; Jingxing Dai; Rongmei Qu; Lin Yuan

    2014-01-01

    Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei-mer’s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Alzheimer’s disease. Lipid rafts are glycolipid-rich liquid domains of the plasma membrane, where certain types of protein tend to aggregate and intercalate. Lipid rafts are involved in the generation of amyloid-beta oligomers and the formation of amyloid-beta peptides. In this paper, we review the mechanism by which lipid rafts disturb the aberrant deg-radative autophagic-lysosomal pathway of amyloid-beta, which plays an important role in the pathological process of Alzheimer’s disease. Moreover, we describe this mechanism from the view of the Two-system Theory of fasciology and thus, suggest that lipid rafts may be a new target of Alzheimer’s disease treatment.

  4. Biochemical and structural characterization of Klebsiella pneumoniae oxamate amidohydrolase in the uric acid degradation pathway

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, Katherine A.; Ealick, Steven E.

    2016-05-25

    HpxW from the ubiquitous pathogenKlebsiella pneumoniaeis involved in a novel uric acid degradation pathway downstream from the formation of oxalurate. Specifically, HpxW is an oxamate amidohydrolase which catalyzes the conversion of oxamate to oxalate and is a member of the Ntn-hydrolase superfamily. HpxW is autoprocessed from an inactive precursor to form a heterodimer, resulting in a 35.5 kDa α subunit and a 20 kDa β subunit. Here, the structure of HpxW is presented and the substrate complex is modeled. In addition, the steady-state kinetics of this enzyme and two active-site variants were characterized. These structural and biochemical studies provide further insight into this class of enzymes and allow a mechanism for catalysis consistent with other members of the Ntn-hydrolase superfamily to be proposed.

  5. Trafficking and degradation pathways in pathogenic conversion of prions and prion-like proteins in neurodegenerative diseases.

    Science.gov (United States)

    Victoria, Guiliana Soraya; Zurzolo, Chiara

    2015-09-01

    Several neurodegenerative diseases such as transmissible spongiform encephalopathies, Alzheimer's and Parkinson's diseases are caused by the conversion of cellular proteins to a pathogenic conformer. Despite differences in the primary structure and subcellular localization of these proteins, which include the prion protein, α-synuclein and amyloid precursor protein (APP), striking similarity has been observed in their ability to seed and convert naïve protein molecules as well as transfer between cells. This review aims to cover what is known about the intracellular trafficking of these proteins as well as their degradation mechanisms and highlight similarities in their movement through the endocytic pathway that could contribute to the pathogenic conversion and seeding of these proteins which underlies the basis of these diseases.

  6. Key enzymes of the protocatechuate branch of the β-ketoadipate pathway for aromatic degradation in Corynebacterium glutamicum

    Institute of Scientific and Technical Information of China (English)

    SHEN; Xihui; LIU; Shuangjiang

    2005-01-01

    Although the protocatechuate branch of the β-ketoadipate pathway in Gram bacteria has been well studied, this branch is less understood in Gram+ bacteria. In this study,Corynebacterium glutamicum was cultivated with protocatechuate, p-cresol, vanillate and 4-hydroxybenzoate as sole carbon and energy sources for growth. Enzymatic assays indicated that growing cells on these aromatic compounds exhibited protocatechuate 3,4-dioxygenase activities. Data-mining of the genome of this bacterium revealed that the genetic locus ncg12314-ncg12315 encoded a putative protocatechuate 3,4-dioxygenase. The genes,ncg12314 and ncg12315, were amplified by PCR technique and were cloned into plasmid (pET21aP34D). Recombinant Escherichia coli strain harboring this plasmid actively expressed protocatechuate 3,4-dioxygenase activity. Further, when this locus was disrupted in C. glutamicum, the ability to degrade and assimilate protocatechuate, p-cresol, vanillate or 4-hydroxybenzoate was lost and protocatechuate 3,4-dioxygenase activity was disappeared. The ability to grow with these aromatic compounds and protocatechuate 3,4-dioxygenase activity of C.glutamicum mutant could be restored by gene complementation. Thus, it is clear that the key enzyme for ring-cleavage, protocatechuate 3,4-dioxygenase, was encoded by ncg12314 and ncg12315. The additional genes involved in the protocatechuate branch of the β-ketoadipate pathway were identified by mining the genome data publically available in the GenBank. The functional identification of genes and their unique organization in C. glutamicum provided new insight into the genetic diversity of aromatic compound degradation.

  7. Oncogenic activation of the Met receptor tyrosine kinase fusion protein, Tpr-Met, involves exclusion from the endocytic degradative pathway.

    Science.gov (United States)

    Mak, H H L; Peschard, P; Lin, T; Naujokas, M A; Zuo, D; Park, M

    2007-11-01

    Multiple mechanisms of dysregulation of receptor tyrosine kinases (RTKs) are observed in human cancers. In addition to gain-of-function, loss of negative regulation also contributes to oncogenic activation of RTKs. Negative regulation of many RTKs involves their internalization and degradation in the lysosome, a process regulated through ubiquitination. RTK oncoproteins activated following chromosomal translocation, are no longer transmembrane proteins, and are predicted to escape lysosomal degradation. To test this, we used the Tpr-Met oncogene, generated following chromosomal translocation of the hepatocyte growth factor receptor (Met). Unlike Met, Tpr-Met is localized in the cytoplasm and also lacks the binding site for Cbl ubiquitin ligases. We determined whether subcellular localization of Tpr-Met, and/or loss of its Cbl-binding site, is important for oncogenic activity. Presence of a Cbl-binding site and ubiquitination of cytosolic Tpr-Met oncoproteins does not alter their transforming activity. In contrast, plasma membrane targeting allows Tpr-Met to enter the endocytic pathway, and Tpr-Met transforming activity as well as protein stability are decreased in a Cbl-dependent manner. We show that transformation by Tpr-Met is in part dependent on its ability to escape normal downregulatory mechanisms. This provides a paradigm for many RTK oncoproteins activated following chromosomal translocation.

  8. Biochemical, transcriptional and translational evidences of the phenol-meta-degradation pathway by the hyperthermophilic Sulfolobus solfataricus 98/2.

    Directory of Open Access Journals (Sweden)

    Alexia Comte

    Full Text Available Phenol is a widespread pollutant and a model molecule to study the biodegradation of monoaromatic compounds. After a first oxidation step leading to catechol in mesophilic and thermophilic microorganisms, two main routes have been identified depending on the cleavage of the aromatic ring: ortho involving a catechol 1,2 dioxygenase (C12D and meta involving a catechol 2,3 dioxygenase (C23D. Our work aimed at elucidating the phenol-degradation pathway in the hyperthermophilic archaea Sulfolobus solfataricus 98/2. For this purpose, the strain was cultivated in a fermentor under different substrate and oxygenation conditions. Indeed, reducing dissolved-oxygen concentration allowed slowing down phenol catabolism (specific growth and phenol-consumption rates dropped 55% and 39%, respectively and thus, evidencing intermediate accumulations in the broth. HPLC/Diode Array Detector and LC-MS analyses on culture samples at low dissolved-oxygen concentration (DOC  =  0.06 mg x L(-1 suggested, apart for catechol, the presence of 2-hydroxymuconic acid, 4-oxalocrotonate and 4-hydroxy-2-oxovalerate, three intermediates of the meta route. RT-PCR analysis on oxygenase-coding genes of S. solfataricus 98/2 showed that the gene coding for the C23D was expressed only on phenol. In 2D-DIGE/MALDI-TOF analysis, the C23D was found and identified only on phenol. This set of results allowed us concluding that S. solfataricus 98/2 degrade phenol through the meta route.

  9. Sources and Input Pathways of Glyphosate and its Degradation Product AMPA

    Science.gov (United States)

    Bischofberger, S.; Hanke, I.; Wittmer, I.; Singer, H.; Stamm, C.

    2009-04-01

    Despite being the pesticide used in the largest quantities worldwide, the environmental relevance of glyphosate has been considered low for many years. Reasons for this assessment were the observations that glyphosate degrades quickly into its degradation product AMPA and that it sorbs strongly to soil particles. Hence, little losses to water bodies had been expected. Research during the last few years however contradicts this expectation. Although glyphosate is a dominant pesticide used in agriculture, recent studies on other pesticides revealed that urban sources may play a significant role for water quality. Therefore this study compares glyphosate input into streams from agricultural and urban sources. For that purpose, a catchment of an area of 25 km2 was selected. It has by about 12'000 inhabitants and about 15 % of the area is used as arable land. Four sampling sites were selected in the river system in order to reflect different urban and agricultural sources. Additionally, we sampled a combined sewer overflow, a rain sewer and the outflow of a waste water treatment plant. At each site discharge was measured continuously from March to November 2007. During 16 rain events samples were taken by automatic devices at a high temporal resolution. To analyze the concentration of glyphosate and its degradation product AMPA, the samples were derivatized with FMOC-Cl at low pH conditions and then filtrated. The solid phase extraction was conducted with Strata-X sorbent cartridge. Glyphosate and AMPA were detected with API 4000 after the chromatography with X bridge column C18. To assure the data quality, interne standards of Glyphosate and AMPA were added to every sample. The limit of detection and quantification for glyphosate and AMPA are bellow 1ng/l. We analyzed two rain events at a high resolution for all stations and several events at the outlet of the catchment. We measured high glyphosate concentration in urban and agriculture dominated catchments with up to

  10. Evidence for isofunctional enzymes in the degradation of phenol, m- and p-toluate, and p-cresol via catechol meta-cleavage pathways in Alcaligenes eutrophus.

    OpenAIRE

    Hughes, E J; Bayly, R C; Skurray, R A

    1984-01-01

    A study of the degradation of phenol, p-cresol, and m- and p-toluate by Alcaligenes eutrophus 345 has provided evidence that these compounds are metabolized via separate catechol meta-cleavage pathways. Analysis of the enzymes synthesized by wild-type and mutant strains and by strains cured of the plasmid pRA1000, which encodes m- and p-toluate degradation, indicated that two or more isofunctional enzymes mediated several steps in the pathway. The formation of three catechol 2,3-oxygenases an...

  11. Microbial oil-degradation under mild hydrostatic pressure (10 MPa): which pathways are impacted in piezosensitive hydrocarbonoclastic bacteria?

    Science.gov (United States)

    Scoma, Alberto; Barbato, Marta; Hernandez-Sanabria, Emma; Mapelli, Francesca; Daffonchio, Daniele; Borin, Sara; Boon, Nico

    2016-01-01

    Oil spills represent an overwhelming carbon input to the marine environment that immediately impacts the sea surface ecosystem. Microbial communities degrading the oil fraction that eventually sinks to the seafloor must also deal with hydrostatic pressure, which linearly increases with depth. Piezosensitive hydrocarbonoclastic bacteria are ideal candidates to elucidate impaired pathways following oil spills at low depth. In the present paper, we tested two strains of the ubiquitous Alcanivorax genus, namely A. jadensis KS_339 and A. dieselolei KS_293, which is known to rapidly grow after oil spills. Strains were subjected to atmospheric and mild pressure (0.1, 5 and 10 MPa, corresponding to a depth of 0, 500 and 1000 m, respectively) providing n-dodecane as sole carbon source. Pressures equal to 5 and 10 MPa significantly lowered growth yields of both strains. However, in strain KS_293 grown at 10 MPa CO2 production per cell was not affected, cell integrity was preserved and PO4(3-) uptake increased. Analysis of its transcriptome revealed that 95% of its genes were downregulated. Increased transcription involved protein synthesis, energy generation and respiration pathways. Interplay between these factors may play a key role in shaping the structure of microbial communities developed after oil spills at low depth and limit their bioremediation potential. PMID:27020120

  12. Microbial oil-degradation under mild hydrostatic pressure (10 MPa): which pathways are impacted in piezosensitive hydrocarbonoclastic bacteria?

    Science.gov (United States)

    Scoma, Alberto; Barbato, Marta; Hernandez-Sanabria, Emma; Mapelli, Francesca; Daffonchio, Daniele; Borin, Sara; Boon, Nico

    2016-03-01

    Oil spills represent an overwhelming carbon input to the marine environment that immediately impacts the sea surface ecosystem. Microbial communities degrading the oil fraction that eventually sinks to the seafloor must also deal with hydrostatic pressure, which linearly increases with depth. Piezosensitive hydrocarbonoclastic bacteria are ideal candidates to elucidate impaired pathways following oil spills at low depth. In the present paper, we tested two strains of the ubiquitous Alcanivorax genus, namely A. jadensis KS_339 and A. dieselolei KS_293, which is known to rapidly grow after oil spills. Strains were subjected to atmospheric and mild pressure (0.1, 5 and 10 MPa, corresponding to a depth of 0, 500 and 1000 m, respectively) providing n-dodecane as sole carbon source. Pressures equal to 5 and 10 MPa significantly lowered growth yields of both strains. However, in strain KS_293 grown at 10 MPa CO2 production per cell was not affected, cell integrity was preserved and PO43‑ uptake increased. Analysis of its transcriptome revealed that 95% of its genes were downregulated. Increased transcription involved protein synthesis, energy generation and respiration pathways. Interplay between these factors may play a key role in shaping the structure of microbial communities developed after oil spills at low depth and limit their bioremediation potential.

  13. Microbial oil-degradation under mild hydrostatic pressure (10 MPa): which pathways are impacted in piezosensitive hydrocarbonoclastic bacteria?

    KAUST Repository

    Scoma, Alberto

    2016-03-29

    Oil spills represent an overwhelming carbon input to the marine environment that immediately impacts the sea surface ecosystem. Microbial communities degrading the oil fraction that eventually sinks to the seafloor must also deal with hydrostatic pressure, which linearly increases with depth. Piezosensitive hydrocarbonoclastic bacteria are ideal candidates to elucidate impaired pathways following oil spills at low depth. In the present paper, we tested two strains of the ubiquitous Alcanivorax genus, namely A. jadensis KS_339 and A. dieselolei KS_293, which is known to rapidly grow after oil spills. Strains were subjected to atmospheric and mild pressure (0.1, 5 and 10 MPa, corresponding to a depth of 0, 500 and 1000 m, respectively) providing n-dodecane as sole carbon source. Pressures equal to 5 and 10 MPa significantly lowered growth yields of both strains. However, in strain KS_293 grown at 10 MPa CO2 production per cell was not affected, cell integrity was preserved and PO43− uptake increased. Analysis of its transcriptome revealed that 95% of its genes were downregulated. Increased transcription involved protein synthesis, energy generation and respiration pathways. Interplay between these factors may play a key role in shaping the structure of microbial communities developed after oil spills at low depth and limit their bioremediation potential.

  14. Characterization of the KstR2 regulator responsible of the lower cholesterol degradative pathway in Mycobacterium smegmatis.

    Science.gov (United States)

    García-Fernández, Julia; Galán, Beatriz; Medrano, Francisco J; García, José L

    2015-02-01

    The interaction of KstR2-dependent promoters of the divergon constituted by the MSMEG_6000-5999 and MSMEG_6001-6004 operons of Mycobacterium smegmatis which encode the genes involved in the lower cholesterol degradative pathway has been characterized. Footprint analyses have demonstrated experimentally for the first time that KstR2 specifically binds to an operator region of 29 nucleotides containing the palindromic sequence AAGCAAGNNCTTGCTT. This region overlaps with the -10 and -35 boxes of the putative P(6000) and P(6001) divergent promoters, suggesting that KstR2 represses their transcription by preventing the binding of the ribonucleic acid polymerase. A three-dimensional model of the KstR2 protein revealed a typical TetR-type regulator folding with two domains, a deoxyribonucleic acid (DNA)-binding N-terminal domain and a regulator-binding C-terminal domain composed by three and six helices respectively. KstR2 is an all alpha protein as confirmed by circular dichroism. We have determined that M. smegmatis is able to grow using sitolactone (HIL) as the only carbon source and that this compound induces the kstR2 regulon in vivo. HIL or its open form 5OH-HIP were unable to release in vitro the KstR2-DNA operator interaction, suggesting that 5OH-HIP-CoA or a further derivative would induce the lower cholesterol catabolic pathway. PMID:25511435

  15. Abatement and degradation pathways of toluene in indoor air by positive corona discharge.

    Science.gov (United States)

    Van Durme, J; Dewulf, J; Sysmans, W; Leys, C; Van Langenhove, H

    2007-08-01

    Indoor air concentrations of volatile organic compounds often exceed outdoor levels by a factor of 5. There is much interest in developing new technologies in order to improve indoor air quality. In this work non-thermal plasma (DC positive corona discharge) is explored as an innovative technology for indoor air purification. An inlet gas stream of 10 l min(-1) containing 0.50+/-0.02 ppm toluene was treated by the plasma reactor in atmospheric conditions. Toluene removal proved to be achievable with a characteristic energy density epsilon(0) of 50 J l(-1). Removal efficiencies were higher for 26% relative humidity (epsilon(0)=35 J l(-1)), compared with those at increased humidities (50% relative humidity, epsilon(0)=49 J l(-1)). Reaction products such as formic acid, benzaldehyde, benzyl alcohol, 3-methyl-4-nitrophenol, 4-methyl-2-nitrophenol, 4-methyl-2-propyl furan, 5-methyl-2-nitrophenol, 4-nitrophenol, 2-methyl-4,6-dinitrophenol are identified by means of mass spectrometry. Based on these by-products a toluene degradation mechanism is proposed. PMID:17490711

  16. Urothelial endocytic vesicle recycling and lysosomal degradative pathway regulated by lipid membrane composition.

    Science.gov (United States)

    Grasso, E J; Calderón, R O

    2013-02-01

    The urothelium, a specialized epithelium that covers the mucosa cell surface of the urinary bladder, undergoes dramatic morphological changes during the micturition cycle that involve a membrane apical traffic. This traffic was first described as a lysosomal pathway, in addition to the known endocytosis/exocytosis membrane recycling. In an attempt to understand the role of membrane lipid composition in those effects, we previously described the lipid-dependent leakage of the endocytosed vesicle content. In this work, we demonstrated clear differences in the traffic of both the fluid probe and the membrane-bound probe in urothelial umbrella cells by using spectrofluorometry and/or confocal and epifluorescence microscopy. Different membrane lipid compositions were established by using three diet formulae enriched in oleic acid, linoleic acid and a commercial formula. Between three and five animals for each dietary treatment were used for each analysis. The decreased endocytosis of both fluid and membrane-bound probes (approximately 32 and 49 % lower, respectively) in oleic acid-derived umbrella cells was concomitant with an increased recycling (approximately 4.0 and 3.7 times, respectively) and diminished sorting to the lysosome (approximately 23 and 37 %, respectively) when compared with the control umbrella cells. The higher intravesicular pH and the impairment of the lysosomal pathway of oleic acid diet-derived vesicles compared to linoleic acid diet-derived vesicles and control diet-derived vesicles correlate with our findings of a lower V-ATPase activity previously reported. We integrated the results obtained in the present and previous work to determine the sorting of endocytosed material (fluid and membrane-bound probes) into the different cell compartments. Finally, the weighted average effect of the individual alterations on the intracellular distribution was evaluated. The results shown in this work add evidences for the modulatory role of the membrane

  17. Cx31 is assembled and trafficked to cell surface by ER-Golgi pathway and degraded by proteasomal or lysosomal pathways

    Institute of Scientific and Technical Information of China (English)

    Li Qiang HE; Zhi Gao LONG; He Ping DAI; Kun XIA; Jia Hui XIA; Zhuo Hua ZHANG; Fang CAI; Yu LIU; Mu Jun LIU; Zhi Ping TAN; Qian PAN; Fai Yan FANG; De Sheng LIANG; Ling Qian WU

    2005-01-01

    Gap junctions, consisting of connexins, allow the exchange of small molecules (<1 kD) between adjacent cells, thus providing a mechanism for synchronizing the responses of groups of cells to environmental stimuli. Connexin 31 is a member of the connexin family. Mutations on connexin 31 are associated with erythrokeratodermia variabilis, hearing impairment and peripheral neuropathy. However, the pathological mechanism for connexin 31 mutants in these diseases are still unknown. In this study, we analyzed the assembly, trafficking and metabolism of connexin 31 in HeLa cells stably expressing connexin 31. Calcein transfer assay showed that calcein transfer was inhibited when cells were treated with Brefeldin A or cytochalasin D, but not when treated with nocodazole or α-glycyrrhetinic acid, suggesting that Golgi apparatus and actin filaments, but not microtubules, are crucial to the trafficking and assembly of connexin 31, as well as the formation of gap junction intercellular communication by connexin 31. Additionally, α-glycyrrhetinic acid did not effectively inhibit gap junctional intercellular communication formed by connexin 31. Pulse-chase assay revealed that connexin 31 had a half-life of about 6 h. Moreover, Western blotting and fluorescent staining demonstrated that in HeLa cells stably expressing connexin 31, the amount of connexin 31 was significantly increased after these cells were treated with proteasomal or lysosomal inhibitors. These findings indicate that connexin 31 was rapidly renewed,and possibly degraded by both proteasomal and lysosomal pathways.

  18. Influence of inorganic acids on the dehydration of fructose to 5-hydroxymethylfurfural over AlCl3 catalyst%无机酸对 AlCl3催化果糖脱水制备5-羟甲基糠醛的影响

    Institute of Scientific and Technical Information of China (English)

    李振斌; 顾运江; 王维; 魏作君; 刘迎新

    2014-01-01

    The dehydration of fructose to 5-hydroxymethylfurfural is the research hotspot of the compre-hensive utilization of biomass resources. Using AlCl3 as the catalyst,the influence of reaction conditions on the dehydration of fructose to 5-hydroxymethylfurfural,especially the addition of different inorganic acids on the catalytic performance of AlCl3 was investigated. Using inorganic acid and AlCl3 as the co-catalyst, the effects of different solvents(1,4-dioxane,N,N-dimethylformamide,2-dimethyl sulfoxide),reaction temperature and the mass ratio of sulphuric acid to phosphoric acid(1: 2、2: 3、3: 2、2: 1)were tested. The results showed that 5-hydroxymethylfurfural yield of 92. 1% was attained under the condition as follows:N,N-dimethylformamide as the solvent,AlCl3 dosage 7. 5 mmol,sulphuric acid concentration 20 mmol·L -1 , phosphoric acid concentration 30 mmol·L - 1 and reaction temperature 120 ℃.%果糖脱水降解为5-羟甲基糠醛是生物质资源综合利用的研究热点。以 AlCl3为催化剂,考察反应条件对果糖脱水制备5-羟甲基糠醛的影响,重点研究不同无机酸对 AlCl3催化果糖降解生成5-羟甲基糠醛反应的影响。以 AlCl3和无机酸为共催化剂,考察在不同溶剂(1,4-二氧六环、N,N -二甲基甲酰胺、2-甲基亚砜)、反应温度和硫酸与磷酸质量比(1:2、2:3、3:2、2:1)条件下对果糖脱水降解制5-羟甲基糠醛的影响。结果表明,以温和的 N,N -二甲基甲酰胺为溶剂,在反应温度120℃、AlCl3用量为7.5 mmol、硫酸为20 mmol·L -1和磷酸为30 mmol·L -1共催化剂条件下,5-羟甲基糠醛收率达92.1%。

  19. Isolation of Alcaligenes sp strain L6 at low oxygen concentrations and degradation of 3-chlorobenzoate via a pathway not involving (chloro)catechols

    NARCIS (Netherlands)

    Krooneman, J; Wieringa, EBA; Moore, ERB; Gerritse, J; Prins, RA; Gottschal, JC

    1996-01-01

    Isolations of 3-chlorobenzoate (3CBA)-degrading aerobic bacteria under reduced O-2, partial pressures yielded organisms which metabolized 3CBA via the gentisate or the protocatechuate pathway rather than via the catechol route. The 3CBA metabolism of one of these isolates, L6, which,vas identified a

  20. Degradation of {gamma}-HCH spiked soil using stabilized Pd/Fe{sup 0} bimetallic nanoparticles: Pathways, kinetics and effect of reaction conditions

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ritu [Ecotoxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Lucknow 226 025, UP (India); Misra, Virendra, E-mail: virendra_misra2001@yahoo.co.in [Ecotoxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Mudiam, Mohana Krishna Reddy [Analytical Chemistry Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Chauhan, Lalit Kumar Singh [Petroleum Toxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Singh, Rana Pratap [Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Lucknow 226 025, UP (India)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer This study explores the potential of CMC-Pd/nFe{sup 0} to degrade {gamma}-HCH in spiked soil. Black-Right-Pointing-Pointer Sorption-desorption characteristics and partitioning of {gamma}-HCH is investigated. Black-Right-Pointing-Pointer Three degradation pathways has been proposed and discussed. Black-Right-Pointing-Pointer {gamma}-HCH degradation mechanism and kinetics is elucidated. Black-Right-Pointing-Pointer Activation energy reveals that {gamma}-HCH degradation is a surface mediated reaction. - Abstract: This study investigates the degradation pathway of gamma-hexachlorocyclohexane ({gamma}-HCH) in spiked soil using carboxymethyl cellulose stabilized Pd/Fe{sup 0} bimetallic nanoparticles (CMC-Pd/nFe{sup 0}). GC-MS analysis of {gamma}-HCH degradation products showed the formation of pentachlorocyclohexene, tri- and di-chlorobenzene as intermediate products while benzene was formed as the most stable end product. On the basis of identified intermediates and final products, degradation pathway of {gamma}-HCH has been proposed. Batch studies showed complete {gamma}-HCH degradation at a loading of 0.20 g/L CMC-Pd/nFe{sup 0} within 6 h of incubation. The surface area normalized rate constant (k{sub SA}) was found to be 7.6 Multiplication-Sign 10{sup -2} L min{sup -1} m{sup -2}. CMC-Pd/nFe{sup 0} displayed {approx}7-fold greater efficiency for {gamma}-HCH degradation in comparison to Fe{sup 0} nanoparticles (nFe{sup 0}), synthesized without CMC and Pd. Further studies showed that increase in CMC-Pd/nFe{sup 0} loading and reaction temperature facilitates {gamma}-HCH degradation, whereas a declining trend in degradation was noticed with the increase in pH, initial {gamma}-HCH concentration and in the presence of cations. The data on activation energy (33.7 kJ/mol) suggests that {gamma}-HCH degradation is a surface mediated reaction. The significance of the study with respect to remediation of {gamma}-HCH contaminated soil using

  1. Characteristics of the Thermal Degradation of Glucose and Maltose Solutions.

    Science.gov (United States)

    Woo, Koan Sik; Kim, Hyun Young; Hwang, In Guk; Lee, Sang Hoon; Jeong, Heon Sang

    2015-06-01

    In order to investigate the thermal degradation of glucose and maltose solutions after high temperature and high pressure (HTHP) treatment, the samples were treated at temperatures of 110, 120, 130, 140, and 150°C for 1, 2, 3, 4, and 5 h in an apparatus for HTHP treatment. Glucose and maltose solutions (20% w/w) were prepared by weighing glucose and maltose and adding distilled water in the desired proportion. Chromaticity, pH, organic acids, 5-hydroxymethylfurfural (HMF), free sugar contents, electron donating ability (EDA), and ascorbic acid equivalent antioxidant capacity (AEAC) were evaluated. With increasing heating temperatures and times, the L-, a-, and b-values decreased. The pH and free sugar contents decreased, and organic acids and HMF contents increased with greater temperatures and times. EDA (%) and the AEAC of the heating sugars increased with the increases in temperatures and times. PMID:26175997

  2. Novel small molecule binders of human N-glycanase 1, a key player in the endoplasmic reticulum associated degradation pathway.

    Science.gov (United States)

    Srinivasan, Bharath; Zhou, Hongyi; Mitra, Sreyoshi; Skolnick, Jeffrey

    2016-10-01

    Peptide:N-glycanase (NGLY1) is an enzyme responsible for cleaving oligosaccharide moieties from misfolded glycoproteins to enable their proper degradation. Deletion and truncation mutations in this gene are responsible for an inherited disorder of the endoplasmic reticulum-associated degradation pathway. However, the literature is unclear whether the disorder is a result of mutations leading to loss-of-function, loss of substrate specificity, loss of protein stability or a combination of these factors. In this communication, without burdening ourselves with the mechanistic underpinning of disease causation because of mutations on the NGLY1 protein, we demonstrate the successful application of virtual ligand screening (VLS) combined with experimental high-throughput validation to the discovery of novel small-molecules that show binding to the transglutaminase domain of NGLY1. Attempts at recombinant expression and purification of six different constructs led to successful expression of five, with three constructs purified to homogeneity. Most mutant variants failed to purify possibly because of misfolding and the resultant exposure of surface hydrophobicity that led to protein aggregation. For the purified constructs, our threading/structure-based VLS algorithm, FINDSITE(comb), was employed to predict ligands that may bind to the protein. Then, the predictions were assessed by high-throughput differential scanning fluorimetry. This led to the identification of nine different ligands that bind to the protein of interest and provide clues to the nature of pharmacophore that facilitates binding. This is the first study that has identified novel ligands that bind to the NGLY1 protein as a possible starting point in the discovery of ligands with potential therapeutic applications in the treatment of the disorder caused by NGLY1 mutants. PMID:27567076

  3. Dysregulation of protein degradation pathways may mediate the liver injury and phospholipidosis associated with a cationic amphiphilic antibiotic drug

    International Nuclear Information System (INIS)

    A large number of antibiotics are known to cause drug-induced liver injury in the clinic; however, interpreting clinical risk is not straightforward owing to a lack of predictivity of the toxicity by standard preclinical species and a poor understanding of the mechanisms of toxicity. An example is PF-04287881, a novel ketolide antibiotic that caused elevations in liver function tests in Phase I clinical studies. In this study, a mouse diversity panel (MDP), comprised of 34 genetically diverse, inbred mouse strains, was utilized to model the toxicity observed with PF-04287881 treatment and investigate potential mechanisms that may mediate the liver response. Significant elevations in serum alanine aminotransferase (ALT) levels in PF-04287881-treated animals relative to vehicle-treated controls were observed in the majority (88%) of strains tested following a seven day exposure. The average fold elevation in ALT varied by genetic background and correlated with microscopic findings of hepatocellular hypertrophy, hepatocellular single cell necrosis, and Kupffer cell vacuolation (confirmed as phospholipidosis) in the liver. Global liver mRNA expression was evaluated in a subset of four strains to identify transcript and pathway differences that distinguish susceptible mice from resistant mice in the context of PF-04287881 treatment. The protein ubiquitination pathway was highly enriched among genes associated with PF-04287881-induced hepatocellular necrosis. Expression changes associated with PF-04287881-induced phospholipidosis included genes involved in drug transport, phospholipid metabolism, and lysosomal function. The findings suggest that perturbations in genes involved in protein degradation leading to accumulation of oxidized proteins may mediate the liver injury induced by this drug. - Highlights: • Identified susceptible and resistant mouse strains to liver injury induced by a CAD • Liver injury characterized by single cell necrosis, and phospholipidosis

  4. Dysregulation of protein degradation pathways may mediate the liver injury and phospholipidosis associated with a cationic amphiphilic antibiotic drug

    Energy Technology Data Exchange (ETDEWEB)

    Mosedale, Merrie [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Wu, Hong [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Kurtz, C. Lisa [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Schmidt, Stephen P. [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Adkins, Karissa, E-mail: Karissa.Adkins@pfizer.com [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Harrill, Alison H. [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); University of Arkansas for Medical Sciences, Little Rock, AR72205 (United States)

    2014-10-01

    A large number of antibiotics are known to cause drug-induced liver injury in the clinic; however, interpreting clinical risk is not straightforward owing to a lack of predictivity of the toxicity by standard preclinical species and a poor understanding of the mechanisms of toxicity. An example is PF-04287881, a novel ketolide antibiotic that caused elevations in liver function tests in Phase I clinical studies. In this study, a mouse diversity panel (MDP), comprised of 34 genetically diverse, inbred mouse strains, was utilized to model the toxicity observed with PF-04287881 treatment and investigate potential mechanisms that may mediate the liver response. Significant elevations in serum alanine aminotransferase (ALT) levels in PF-04287881-treated animals relative to vehicle-treated controls were observed in the majority (88%) of strains tested following a seven day exposure. The average fold elevation in ALT varied by genetic background and correlated with microscopic findings of hepatocellular hypertrophy, hepatocellular single cell necrosis, and Kupffer cell vacuolation (confirmed as phospholipidosis) in the liver. Global liver mRNA expression was evaluated in a subset of four strains to identify transcript and pathway differences that distinguish susceptible mice from resistant mice in the context of PF-04287881 treatment. The protein ubiquitination pathway was highly enriched among genes associated with PF-04287881-induced hepatocellular necrosis. Expression changes associated with PF-04287881-induced phospholipidosis included genes involved in drug transport, phospholipid metabolism, and lysosomal function. The findings suggest that perturbations in genes involved in protein degradation leading to accumulation of oxidized proteins may mediate the liver injury induced by this drug. - Highlights: • Identified susceptible and resistant mouse strains to liver injury induced by a CAD • Liver injury characterized by single cell necrosis, and phospholipidosis

  5. RINL, guanine nucleotide exchange factor Rab5-subfamily, is involved in the EphA8-degradation pathway with odin.

    Directory of Open Access Journals (Sweden)

    Hiroaki Kajiho

    Full Text Available The Rab family of small guanosine triphosphatases (GTPases plays a vital role in membrane trafficking. Its active GTP-bound state is driven by guanine nucleotide-exchange factors (GEFs. Ras and Rab interactor (or Ras interaction/interference-like (RINL, which contains a conserved VPS9 domain critical for GEF action, was recently identified as a new Rab5 subfamily GEF in vitro. However, its detailed function and interacting molecules have not yet been fully elucidated. Here we found that RINL has GEF activity for the Rab5 subfamily proteins by measuring their GTP-bound forms in cultured cells. We also found that RINL interacts with odin, a member of the ankyrin-repeat and sterile-alpha motif (SAM domain-containing (Anks protein family. In addition, the Eph tyrosine kinase receptor EphA8 formed a ternary complex with both RINL and odin. Interestingly, RINL expression in cultured cells reduced EphA8 levels in a manner dependent on both its GEF activity and interaction with odin. In addition, knockdown of RINL increased EphA8 level in HeLa cells. Our findings suggest that RINL, as a GEF for Rab5 subfamily, is implicated in the EphA8-degradation pathway via its interaction with odin.

  6. Biodegradability of HCH in agricultural soils from Guadeloupe (French West Indies): identification of the lin genes involved in the HCH degradation pathway.

    Science.gov (United States)

    Laquitaine, L; Durimel, A; de Alencastro, L F; Jean-Marius, C; Gros, O; Gaspard, S

    2016-01-01

    Banana has been a main agricultural product in the French West Indies (Guadeloupe and Martinique) since the 1960s. This crop requires the intensive use of pesticides to prevent attacks by insect pests. Chlorinated pesticides, such as hexachlorocyclohexane (HCH), chlordecone and dieldrin, were used until the beginning of the 1990s, resulting in a generalized diffuse contamination of the soil and water in the areas of banana production, hence the need to develop solutions for cleanup of the polluted sites. The aims of this work were (i) to assess lindane degradation in soil slurry microcosms treated with lindane at 10 mg/L and (ii) to detect the catabolic genes involved in the HCH degradation pathway. The soil slurry microcosm system showed a 40% lindane degradation efficiency at the end of a 30-day experiment. Lower lindane removal was also detected in the abiotic controls, probably caused by pesticide adsorption to soil particles. Indeed, the lindane concentration decreased from 6000 to 1330 ng/mL and from 800 to 340 ng/mL for the biotic and abiotic soils, respectively. Nevertheless, some of the genes involved in the HCH degradation pathway were amplified by polymerase chain reaction (PCR) from crude deoxyribonucleic acid (DNA) extracted from the Guadeloupe agricultural soil, suggesting that HCH degradation is probably mediated by bacteria closely related to the family Sphingomonadaceae.

  7. Genetic associations of type 2 diabetes with islet amyloid polypeptide processing and degrading pathways in asian populations.

    Directory of Open Access Journals (Sweden)

    Vincent Kwok Lim Lam

    Full Text Available Type 2 diabetes (T2D is a complex disease characterized by beta cell dysfunctions. Islet amyloid polypeptide (IAPP is highly conserved and co-secreted with insulin with over 40% of autopsy cases of T2D showing islet amyloid formation due to IAPP aggregation. Dysregulation in IAPP processing, stabilization and degradation can cause excessive oligomerization with beta cell toxicity. Previous studies examining genetic associations of pathways implicated in IAPP metabolism have yielded conflicting results due to small sample size, insufficient interrogation of gene structure and gene-gene interactions. In this multi-staged study, we screened 89 tag single nucleotide polymorphisms (SNPs in 6 candidate genes implicated in IAPP metabolism and tested for independent and joint associations with T2D and beta cell dysfunctions. Positive signals in the stage-1 were confirmed by de novo and in silico analysis in a multi-centre unrelated case-control cohort. We examined the association of significant SNPs with quantitative traits in a subset of controls and performed bioinformatics and relevant functional analyses. Amongst the tag SNPs, rs1583645 in carboxypeptidase E (CPE and rs6583813 in insulin degrading enzyme (IDE were associated with 1.09 to 1.28 fold increased risk of T2D (P Meta = 9.4×10(-3 and 0.02 respectively in a meta-analysis of East Asians. Using genetic risk scores (GRS with each risk variant scoring 1, subjects with GRS≥3 (8.2% of the cohort had 56% higher risk of T2D than those with GRS = 0 (P = 0.01. In a subcohort of control subjects, plasma IAPP increased and beta cell function index declined with GRS (P = 0.008 and 0.03 respectively. Bioinformatics and functional analyses of CPE rs1583645 predicted regulatory elements for chromatin modification and transcription factors, suggesting differential DNA-protein interactions and gene expression. Taken together, these results support the importance of dysregulation of IAPP

  8. Towards a Biocatalyst for (S)-Styrene Oxide Production: Characterization of the Styrene Degradation Pathway of Pseudomonas sp. Strain VLB120

    OpenAIRE

    Panke, Sven; Witholt, Bernard; Schmid, Andreas; Wubbolts, Marcel G.

    1998-01-01

    In order to design a biocatalyst for the production of optically pure styrene oxide, an important building block in organic synthesis, the metabolic pathway and molecular biology of styrene degradation in Pseudomonas sp. strain VLB120 was investigated. A 5.7-kb XhoI fragment, which contained on the same strand of DNA six genes involved in styrene degradation, was isolated from a gene library of this organism in Escherichia coli by screening for indigo formation. T7 RNA polymerase expression e...

  9. Sulfamethoxazole in poultry wastewater: Identification, treatability and degradation pathway determination in a membrane-photocatalytic slurry reactor.

    Science.gov (United States)

    Asha, Raju C; Kumar, Mathava

    2015-01-01

    The presence of sulfamethoxazole (SMX) in a real-time poultry wastewater was identified via HPLC analysis. Subsequently, SMX removal from the poultry wastewater was investigated using a continuous-mode membrane-photocatalytic slurry reactor (MPSR). The real-time poultry wastewater was found to have an SMX concentration of 0-2.3 mg L(-1). A granular activated carbon supported TiO2 (GAC-TiO2) was synthesized, characterized and used in MPSR experiments. The optimal MPSR condition, i.e., HRT ∼ 125 min and catalyst dosage 529.3 mg L(-1), for complete SMX removal was found out using unconstrained optimization technique. Under the optimized condition, the effect of SMX concentration on MPSR performance was investigated by synthetic addition of SMX (i.e., 1, 25, 50, 75 and 100 mg L(-1)) into the wastewater. Interestingly, complete removals of total volatile solids (TVS), biochemical oxygen demand (BOD) and SMX were observed under all SMX concentrations investigated. However, a decline in SMX removal rate and proportionate increase in transmembrane-pressure (TMP) were observed when the SMX concentration was increased to higher levels. In the MPSR, the SMX mineralization was through one of the following degradation pathways: (i) fragmentation of the isoxazole ring and (ii) the elimination of methyl and amide moieties followed by the formation of phenyl sulfinate ion. These results show that the continuous-mode MPSR has great potential in the removal for SMX contaminated real-time poultry wastewater and similar organic micropollutants from wastewater. PMID:26121016

  10. The ubiquitin+proteasome protein degradation pathway as a therapeutic strategy in the treatment of solid tumor malignancies.

    Science.gov (United States)

    Driscoll, James J; Minter, Alex; Driscoll, Daniel A; Burris, Jason K

    2011-02-01

    A concept that currently steers the development of cancer therapies has been that agents directed against specific proteins that facilitate tumorigenesis or maintain a malignant phenotype will have greater efficacy, less toxicity and a more sustained response relative to traditional cytotoxic chemotherapeutic agents. The clinical success of the targeted agent Imatinib mesylate as an inhibitor of the tyrosine kinase associated with the breakpoint cluster region-Abelson oncogene locus (BCR-ABL) in the treatment of Philadelphia-positive chronic myelogenous leukemia (CML) has served as a paradigm. While intellectually gratifying, the selective targeting of a single driver event by a small molecule, e.g., kinase inhibitor, to dampen a tumor-promoting pathway in the treatment of solid tumors is limited by many factors. Focus can alternatively be placed on targeting fundamental cellular processes that regulate multiple events, e.g., protein degradation, through the Ubiquitin (Ub)+Proteasome System (UPS). The UPS plays a critical role in modulating numerous cellular proteins to regulate cellular processes such as signal transduction, growth, proliferation, differentiation and apoptosis. Clinical success with the proteasome inhibitor bortezomib revolutionized treatment of B-cell lineage malignancies such as Multiple Myeloma (MM). However, many patients harbor primary resistance and do not respond to bortezomib and those that do respond inevitably develop resistance (secondary resistance). The lack of clinical efficacy of proteasome inhibitors in the treatment of solid tumors may be linked mechanistically to the resistance detected during treatment of hematologic malignancies. Potential mechanisms of resistance and means to improve the response to proteasome inhibitors in solid tumors are discussed.

  11. Photolysis of model emerging contaminants in ultra-pure water: kinetics, by-products formation and degradation pathways.

    Science.gov (United States)

    Benitez, F Javier; Acero, Juan L; Real, Francisco J; Roldan, Gloria; Rodriguez, Elena

    2013-02-01

    The photolysis of five frequent emerging contaminants (Benzotriazole, Chlorophene, N,N-diethyl-m-toluamide or DEET, Methylindole, and Nortriptyline HCl) was investigated in ultrapure water under monochromatic ultraviolet radiation at 254 nm and by a combination of UV and hydrogen peroxide. The results revealed that the photolysis rates followed first-order kinetics, with rate constant values depending on the nature of the specific compound, the pH, and the presence or absence of the scavenger tert-butanol. Quantum yields were also determined and values in the range of 53.8 × 10⁻³ - 9.4 × 10⁻³ mol E⁻¹ for Benzotriazole, 525 × 10⁻³ - 469 × 10⁻³ mol E⁻¹ for Chlorophene, 2.8 × 10⁻³ - 0.9 × 10⁻³ mol E⁻¹ for DEET, 108 × 10⁻³ - 165 × 10⁻³ mol E⁻¹ for Methylindole, and 13.8 × 10⁻³ - 15.0 × 10⁻³ mol E⁻¹ for Nortriptyline were obtained. The study also found that the UV/H₂O₂ process enhanced the oxidation rate in comparison to direct photolysis. High-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) technique was applied to the concentrations evaluation and further identification of the parent compounds and their by-products, which allowed the proposal of the degradation pathways for each compound. Finally, in order to assess the aquatic toxicity in the photodegradation of these compounds, the Vibrio fischeri acute toxicity test was used, and the results indicated an initial increase of this parameter in all cases, followed by a decrease in the specific case of Benzotriazole, DEET, Methylindole, and Chlorophene.

  12. A combined experimental and computational study of the mechanism of fructose dehydration to 5-hydroxymethylfurfural in dimethylsulfoxide using Amberlyst 70, PO43-/niobic acid, or sulfuric acid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing [Northwestern Univ., Evanston, IL (United States); Das, Anirban [Northwestern Univ., Evanston, IL (United States); Assary, Rajeev S. [Argonne National Lab. (ANL), Argonne, IL (United States); Curtiss, Larry A. [Argonne National Lab. (ANL), Argonne, IL (United States); Weitz, Eric [Northwestern Univ., Evanston, IL (United States)

    2016-02-01

    We report on a combined experimental and theoretical study of the acid catalyzed dehydration of d-fructose in dimethylsulfoxide (DMSO) using; Amberlyst 70, PO43-/niobic acid, and sulfuric acid as catalysts. The reaction has been studied and intermediates characterized using; 13C, 1H, and 17O NMR, and high resolution electrospray ionization mass spectrometry (HR ESI–MS). High level G4MP2 theory calculations are used to understand the thermodynamic landscape for the reaction mechanism in DMSO. We have experimentally identified two key intermediates in the dehydration of fructose to form HMF that were also identified, using theory, as local minima on the potential surface for reaction. A third intermediate, a species capable of undergoing keto–enol tautomerism, was also experimentally detected. However, it was not possible to experimentally distinguish between the keto and the enol forms. These data with different catalysts are consistent with common intermediates along the reaction pathway from fructose to HMF in DMSO. The role of oxygen in producing acidic species in reactions carried out in DMSO in presence of air is also discussed.

  13. Activation of the cAMP/PKA pathway induces UT-A1 urea transporter monoubiquitination and targets it for lysosomal degradation.

    Science.gov (United States)

    Su, Hua; Chen, Minguang; Sands, Jeff M; Chen, Guangping

    2013-12-15

    Regulation of urea transporter UT-A1 in the kidney is important for the urinary concentrating mechanism. We previously reported that activation of the cAMP/PKA pathway by forskolin (FSK) leads to UT-A1 ubiquitination, endocytosis, and degradation. In this study, we discovered that FSK-induced UT-A1 ubiquitination is monoubiquitination as judged by immunoblotting with specific ubiquitin antibodies to the different linkages of the ubiquitin chain. UT-A1 monoubiquitination induced by FSK was processed mainly on the cell plasma membrane. Monoubiquitination facilitates UT-A1 endocytosis, and internalized UT-A1 is accumulated in the early endosome. Inhibition of ubiquitination by E1 ubiquitin-activating enzyme inhibitor PYR-41 significantly reduced FSK-induced UT-A1 endocytosis and degradation. Interestingly, FSK-stimulated UT-A1 degradation occurs through a lysosomal protein degradation system. We further found that the PKA phosphorylation sites of UT-A1 at Ser486 and Ser499 are required for FSK-induced UT-A1 monoubiquitination. The physiological significance was confirmed using rat kidney inner medullary collecting duct suspensions, which showed that vasopressin treatment promotes UT-A1 ubiquitination. We conclude that unlike under basal conditions in which UT-A1 is subject to polyubiquitination and proteasome-mediated protein degradation, activation of UT-A1 by FSK induces UT-A1 monoubiquitination and protein lysosomal degradation.

  14. GABA shunt and polyamine degradation pathway on γ-aminobutyric acid accumulation in germinating fava bean (Vicia faba L.) under hypoxia.

    Science.gov (United States)

    Yang, Runqiang; Guo, Qianghui; Gu, Zhenxin

    2013-01-01

    GABA shunt and polyamine degradation pathway on γ-aminobutyric acid (GABA) accumulation in germinating fava bean under hypoxia was investigated. GABA content, GAD and DAO activity were significantly increased under hypoxia treatment. Glu and polyamine contents enhanced largely and thus supplied as sufficient substrates for GABA formation. In contrast, GABA content decreased, mainly in the embryo, after removing the hypoxia stress. DAO activity, Glu and polyamines contents decreased, while an increment of GAD activity was observed. This indicated that GAD activity can be not only regulated by hypoxia, but by the rapid growth of embryo after the recovery from hypoxia stress. When treated with AG, DAO activity was almost inhibited completely, and the GABA content decreased by 32.96% and 32.07% after treated for 3 and 5 days, respectively. Hence, it can be inferred that about 30% of GABA formed in germinating fava bean under hypoxia was supplied by polyamine degradation pathway.

  15. GABA shunt and polyamine degradation pathway on γ-aminobutyric acid accumulation in germinating fava bean (Vicia faba L.) under hypoxia.

    Science.gov (United States)

    Yang, Runqiang; Guo, Qianghui; Gu, Zhenxin

    2013-01-01

    GABA shunt and polyamine degradation pathway on γ-aminobutyric acid (GABA) accumulation in germinating fava bean under hypoxia was investigated. GABA content, GAD and DAO activity were significantly increased under hypoxia treatment. Glu and polyamine contents enhanced largely and thus supplied as sufficient substrates for GABA formation. In contrast, GABA content decreased, mainly in the embryo, after removing the hypoxia stress. DAO activity, Glu and polyamines contents decreased, while an increment of GAD activity was observed. This indicated that GAD activity can be not only regulated by hypoxia, but by the rapid growth of embryo after the recovery from hypoxia stress. When treated with AG, DAO activity was almost inhibited completely, and the GABA content decreased by 32.96% and 32.07% after treated for 3 and 5 days, respectively. Hence, it can be inferred that about 30% of GABA formed in germinating fava bean under hypoxia was supplied by polyamine degradation pathway. PMID:23017406

  16. Degradation kinetics of the main carbohydrates in birch wood during hot water extraction in a batch reactor at elevated temperatures.

    Science.gov (United States)

    Borrega, Marc; Nieminen, Kaarlo; Sixta, Herbert

    2011-11-01

    Hot water extraction of wood at elevated temperatures may be a suitable method to produce hemicellulose-lean pulps and to recover xylan-derived products from the water extract. In this study, water extractions of birch wood were conducted at temperatures between 180 and 240 °C in a batch reactor. Xylan was extensively removed, whereas cellulose was partly degraded only at temperatures above 180 °C. Under severe extraction conditions, acetic acid content in the water extract was higher than the corresponding amount of acetyl groups in wood. In addition to oligo- and monosaccharides, considerable amounts of furfural and 5-hydroxymethylfurfural (HMF) were recovered from the extracts. After reaching a maximum, the furfural yield remained constant with increasing extraction time. This maximum slightly decreased with increasing extraction temperature, suggesting the preferential formation of secondary degradation products from xylose. Kinetic models fitting experimental data are proposed to explain degradation and conversion reactions of xylan and glucan. PMID:21967712

  17. Degradation kinetics of the main carbohydrates in birch wood during hot water extraction in a batch reactor at elevated temperatures.

    Science.gov (United States)

    Borrega, Marc; Nieminen, Kaarlo; Sixta, Herbert

    2011-11-01

    Hot water extraction of wood at elevated temperatures may be a suitable method to produce hemicellulose-lean pulps and to recover xylan-derived products from the water extract. In this study, water extractions of birch wood were conducted at temperatures between 180 and 240 °C in a batch reactor. Xylan was extensively removed, whereas cellulose was partly degraded only at temperatures above 180 °C. Under severe extraction conditions, acetic acid content in the water extract was higher than the corresponding amount of acetyl groups in wood. In addition to oligo- and monosaccharides, considerable amounts of furfural and 5-hydroxymethylfurfural (HMF) were recovered from the extracts. After reaching a maximum, the furfural yield remained constant with increasing extraction time. This maximum slightly decreased with increasing extraction temperature, suggesting the preferential formation of secondary degradation products from xylose. Kinetic models fitting experimental data are proposed to explain degradation and conversion reactions of xylan and glucan.

  18. Use of 13C NMR and ftir for elucidation of degradation pathways during natural litter decomposition and composting I. early stage leaf degradation

    Science.gov (United States)

    Wershaw, R. L.; Leenheer, J.A.; Kennedy, K.R.; Noyes, T.I.

    1996-01-01

    Oxidative degradation of plant tissue leads to the formation of natural dissolved organic carbon (DOC) and humus. Infrared (IR) and 13C nuclear magnetic resonance (NMR) spectrometry have been used to elucidate the chemical reactions of the early stages of degradation that give rise to DOC derived from litter and compost. The results of this study indicate that oxidation of the lignin components of plant tissue follows the sequence of O-demethylation, and hydroxylation followed by ring-fission, chain-shortening, and oxidative removal of substituents. Oxidative ring-fission leads to the formation of carboxylic acid groups on the cleaved ends of the rings and, in the process, transforms phenolic groups into aliphatic alcoholic groups. The carbohydrate components are broken down into aliphatic hydroxy acids and aliphatic alcohols.

  19. Use of 13C NMR and FTIR for elucidation of degradation pathways during natural litter decomposition and composting. I. Early stage leaf degradation

    International Nuclear Information System (INIS)

    Oxidative degradation of plant tissue leads to the formation of natural dissolved organic carbon (DOC) and humus. Infrared (IR) and 13C nuclear magnetic resonance (NMR) spectrometry have been used to elucidate the chemical reactions of the early stages of degradation that give rise to DOC derived from litter and compost. The results of this study indicate that oxidation of the lignin components of plant tissue follows the sequence of O-demethylation, and hydroxylation followed by ring-fission, chain-shortening, and oxidative removal of substituents. Oxidative ring-fission leads to the formation of carboxylic acid groups on the cleaved ends of the rings and, in the process, transforms phenolic groups into aliphatic alcoholic groups. The carbohydrate components are broken down into aliphatic hydroxy acids and aliphatic alcohols. (author)

  20. WO3/ZrO2 as Solid Acid Catalyst for the Dehydration of Fructose to 5-hydroxymethylfurfural%WO3/ZrO2固体酸催化果糖制备5-羟甲基糠醛的工艺研究

    Institute of Scientific and Technical Information of China (English)

    张迎周; 张玉军; 刘玄; 任亚辉; 许元栋

    2013-01-01

      通过偏钨酸铵水溶液浸渍氢氧化锆制备了 WO3/ZrO2固体酸催化剂,并考察其在果糖脱水制备5-羟甲基糠醛过程中的催化性能。考察了 WO3负载量、催化剂用量、反应时间、反应温度、果糖添加量对 HMF 产率的影响。实验结果表明:WO3负载量为30%,以二甲基亚砜(DMSO)为溶剂,120℃下反应2 h 时,催化剂表现出较高的反应活性,相应 HMF 收率为65.4%。该催化剂循环使用5次,HMF 收率仍能保持62.1%。%WO3/ZrO2 catalysts were prepared by impregnation of zirconium hydroxide with ammonium metatungstate. The WO3/ZrO2 was evaluated as catalyst for the dehydration of fructose to 5-hydroxymethylfurfural. The effects of WO3 loading, the amount of catalyst, reaction time, reaction temperature and the amount of fructose were investigated in detail. With the catalyst of 30 wt% WO3 loading, HMF yield of 65.4 % could be attained at 120 ℃ for 2 h using DMSO as solvent. Moreover, the catalyst could be reused five times without loss of activity.

  1. Use of dual carbon-chlorine isotope analysis to assess the degradation pathways of 1,1,1-trichloroethane in groundwater.

    Science.gov (United States)

    Palau, Jordi; Jamin, Pierre; Badin, Alice; Vanhecke, Nicolas; Haerens, Bruno; Brouyère, Serge; Hunkeler, Daniel

    2016-04-01

    Compound-specific isotope analysis (CSIA) is a powerful tool to track contaminant fate in groundwater. However, the application of CSIA to chlorinated ethanes has received little attention so far. These compounds are toxic and prevalent groundwater contaminants of environmental concern. The high susceptibility of chlorinated ethanes like 1,1,1-trichloroethane (1,1,1-TCA) to be transformed via different competing pathways (biotic and abiotic) complicates the assessment of their fate in the subsurface. In this study, the use of a dual C-Cl isotope approach to identify the active degradation pathways of 1,1,1-TCA is evaluated for the first time in an aerobic aquifer impacted by 1,1,1-TCA and trichloroethylene (TCE) with concentrations of up to 20 mg/L and 3.4 mg/L, respectively. The reaction-specific dual carbon-chlorine (C-Cl) isotope trends determined in a recent laboratory study illustrated the potential of a dual isotope approach to identify contaminant degradation pathways of 1,1,1-TCA. Compared to the dual isotope slopes (Δδ(13)C/Δδ(37)Cl) previously determined in the laboratory for dehydrohalogenation/hydrolysis (DH/HY, 0.33 ± 0.04) and oxidation by persulfate (∞), the slope determined from field samples (0.6 ± 0.2, r(2) = 0.75) is closer to the one observed for DH/HY, pointing to DH/HY as the predominant degradation pathway of 1,1,1-TCA in the aquifer. The observed deviation could be explained by a minor contribution of additional degradation processes. This result, along with the little degradation of TCE determined from isotope measurements, confirmed that 1,1,1-TCA is the main source of the 1,1-dichlorethylene (1,1-DCE) detected in the aquifer with concentrations of up to 10 mg/L. This study demonstrates that a dual C-Cl isotope approach can strongly improve the qualitative and quantitative assessment of 1,1,1-TCA degradation processes in the field. PMID:26874254

  2. Cloning and expression of meta-cleavage enzyme (CarB of carbazole degradation pathway from Pseudomonas stutzeri

    Directory of Open Access Journals (Sweden)

    Ariane Leites Larentis

    2005-06-01

    Full Text Available In this work, the 1082bp PCR product corresponding to carBaBb genes that encode the heterotetrameric enzyme 2'-aminobiphenyl-2,3-diol 1,2-dioxygenase (CarB, involved in the Pseudomonas stutzeri ATCC 31258 carbazole degradation pathway, was cloned using the site-specific recombination system. Recombinant clones were confirmed by PCR, restriction enzyme digestion and sequencing. CarB dioxygenase was expressed in high levels and in active form in Escherichia coli BL21-SI using the His-tagged expression vector pDEST TM17 and salt induction for 4h.Carbazol e seus derivados são compostos nitrogenados aromáticos, presentes comumente em petróleo e potencialmente poluentes. A rota de biodegradação de carbazol a ácido antranílico em Pseudomonas sp. é composta por três enzimas responsáveis, respectivamente, pelas reações de dioxigenação angular, meta-clivagem e hidrólise. A segunda enzima da rota, 2'-aminobifenil-2,3-diol 1,2-dioxigenase (CarB, codificada por dois genes (carBa e carBb, é um heterotetrâmero com atividade catalítica na quebra do anel catecol do susbtrato na posição meta. Neste trabalho, foi clonado o produto de PCR de 1082pb correspondente aos genes carBaBb da bactéria degradadora de carbazol Pseudomonas stutzeri ATCC 31258. A estratégia de clonagem empregada foi a de recombinação sítio-específica e a construção dos plasmídeos foi confirmada por PCR, digestão com enzima de restrição e seqüenciamento. A enzima ativa foi expressa em altas concentrações em vetor pDEST TM17 com cauda de histidina e promotor T7 em Escherichia coli BL21-SI com indução por NaCl durante 4h.

  3. The Homogentisate Pathway: a Central Catabolic Pathway Involved in the Degradation of l-Phenylalanine, l-Tyrosine, and 3-Hydroxyphenylacetate in Pseudomonas putida

    OpenAIRE

    Arias-Barrau, Elsa; Olivera, Elías R.; Luengo, José M.; Fernández, Cristina; Galán, Beatriz; García, José L.; Díaz, Eduardo; Miñambres, Baltasar

    2004-01-01

    Pseudomonas putida metabolizes Phe and Tyr through a peripheral pathway involving hydroxylation of Phe to Tyr (PhhAB), conversion of Tyr into 4-hydroxyphenylpyruvate (TyrB), and formation of homogentisate (Hpd) as the central intermediate. Homogentisate is then catabolized by a central catabolic pathway that involves three enzymes, homogentisate dioxygenase (HmgA), fumarylacetoacetate hydrolase (HmgB), and maleylacetoacetate isomerase (HmgC), finally yielding fumarate and acetoacetate. Wherea...

  4. Predicted thermochemistry for chemical conversions of 5-hydroxymethylfurfural.

    Energy Technology Data Exchange (ETDEWEB)

    Assary, R. S.; Redfern, P. C.; Hammond, J. R.; Greeley, J.; Curtiss, L. A.; Northwestern Univ.

    2010-09-10

    The thermochemistry of various chemical transformations of 5-hydroxy methyl furfural (HMF) were investigated using highly accurate Gaussian-4 (G4) theory. The conversion of HMF to nonane through aldol condensation, hydrogenation, and hydrogenolysis reactions was found to be thermodynamically favorable. The hydrogenation reactions involving the keto groups in the nonane reaction sequence were found to be enhanced at low temperatures and high pressures of H{sub 2}. The hydrogenation, selective oxidation, and hydration of HMF were also found to be thermodynamically favorable. Gas phase enthalpies of formation of all the intermediate compounds were calculated at the G4 level of theory and compared against existing experimental data.

  5. Predicted thermochemistry for chemical conversions of 5-hydroxymethylfurfural

    Science.gov (United States)

    Assary, Rajeev S.; Redfern, Paul C.; Hammond, Jeff R.; Greeley, Jeffrey; Curtiss, Larry A.

    2010-09-01

    The thermochemistry of various chemical transformations of 5-hydroxy methyl furfural (HMF) were investigated using highly accurate G AUSSIAN-4 (G4) theory. The conversion of HMF to nonane through aldol condensation, hydrogenation, and hydrogenolysis reactions was found to be thermodynamically favorable. The hydrogenation reactions involving the keto groups in the nonane reaction sequence were found to be enhanced at low temperatures and high pressures of H 2. The hydrogenation, selective oxidation, and hydration of HMF were also found to be thermodynamically favorable. Gas phase enthalpies of formation of all the intermediate compounds were calculated at the G4 level of theory and compared against existing experimental data.

  6. The dominant acetate degradation pathway/methanogenic composition in full-scale anaerobic digesters operating under different ammonia levels

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2014-01-01

    operating under different ammonia levels were sampled, and the residual biogas production was followed in fed-batch reactors. Acetate, labelled in the methyl group, was used to determine the methanogenic pathway by following the 14CH4 and 14CO2 production. Fluorescence in situ hybridisation was used...... to determine the methanogenic communities’ composition. Results obtained clearly demonstrated that syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis was the dominant pathway in all digesters with high ammonia levels (2.8–4.57 g NH4 +-N L−1), while acetoclastic methanogenic pathway...

  7. MIR125B1 represses the degradation of the PML-RARA oncoprotein by an autophagy-lysosomal pathway in acute promyelocytic leukemia.

    Science.gov (United States)

    Zeng, Cheng-Wu; Chen, Zhen-Hua; Zhang, Xing-Ju; Han, Bo-Wei; Lin, Kang-Yu; Li, Xiao-Juan; Wei, Pan-Pan; Zhang, Hua; Li, Yangqiu; Chen, Yue-Qin

    2014-10-01

    Acute promyelocytic leukemia (APL) is characterized by the t(15;17)-associated PML-RARA fusion gene. We have previously found that MIR125B1 is highly expressed in patients with APL and may be associated with disease pathogenesis; however, the mechanism by which MIR125B1 exerts its oncogenic potential has not been fully elucidated. Here, we demonstrated that MIR125B1 abundance correlates with the PML-RARA status. MIR125B1 overexpression enhanced PML-RARA expression and inhibited the ATRA-induced degradation of the PML-RARA oncoprotein. RNA-seq analysis revealed a direct link between the PML-RARA degradation pathway and MIR125B1-arrested differentiation. We further demonstrated that the MIR125B1-mediated blockade of PML-RARA proteolysis was regulated via an autophagy-lysosomal pathway, contributing to the inhibition of APL differentiation. Furthermore, we identified DRAM2 (DNA-damage regulated autophagy modulator 2), a critical regulator of autophagy, as a novel target that was at least partly responsible for the function of MIR125B1 involved in autophagy. Importantly, the knockdown phenotypes for DRAM2 are similar to the effects of overexpressing MIR125B1 as impairment of PML-RARA degradation, inhibition of autophagy, and myeloid cell differentiation arrest. These effects of MIR125B1 and its target DRAM2 were further confirmed in an APL mouse model. Thus, MIR125B1 dysregulation may interfere with the effectiveness of ATRA-mediated differentiation through an autophagy-dependent pathway, representing a novel potential APL therapeutic target.

  8. Transposon mutagenesis and cloning analysis of the pathways for degradation of 2,4-dichlorophenoxyacetic acid and 3-chlorobenzoate in Alcaligenes eutrophus JMP134(pJP4).

    OpenAIRE

    Don, R H; Weightman, A J; Knackmuss, H J; Timmis, K N

    1985-01-01

    Plasmid pJP4 permits its host bacterium, strain JMP134, to degrade and utilize as sole sources of carbon and energy 3-chlorobenzoate and 2,4-dichlorophenoxyacetic acid (R. H. Don and J. M. Pemberton, J. Bacteriol. 145:681-686, 1981). Mutagenesis of pJP4 by transposons Tn5 and Tn1771 enabled localization of five genes for enzymes involved in these catabolic pathways. Four of the genes, tfdB, tfdC, tfdD, and tfdE, encoded 2,4-dichlorophenol hydroxylase, dichlorocatechol 1,2-dioxygenase, chlorom...

  9. Identification and characterization of the furfural and 5-(hydroxymethyl)furfural degradation pathways of Cupriavidus basilensis HMF14

    OpenAIRE

    Koopman, Frank; Wierckx, Nick; de Winde, Johannes H; Ruijssenaars, Harald J.

    2010-01-01

    The toxic fermentation inhibitors in lignocellulosic hydrolysates pose significant problems for the production of second-generation biofuels and biochemicals. Among these inhibitors, 5-(hydroxymethyl)furfural (HMF) and furfural are specifically notorious. In this study, we describe the complete molecular identification and characterization of the pathway by which Cupriavidus basilensis HMF14 metabolizes HMF and furfural. The identification of this pathway enabled the construction of an HMF an...

  10. Blocking phosphatidylcholine utilization in Pseudomonas aeruginosa, via mutagenesis of fatty acid, glycerol and choline degradation pathways, confirms the importance of this nutrient source in vivo.

    Directory of Open Access Journals (Sweden)

    Zhenxin Sun

    Full Text Available Pseudomonas aeruginosa can grow to very high-cell-density (HCD during infection of the cystic fibrosis (CF lung. Phosphatidylcholine (PC, the major component of lung surfactant, has been hypothesized to support HCD growth of P. aeruginosa in vivo. The phosphorylcholine headgroup, a glycerol molecule, and two long-chain fatty acids (FAs are released by enzymatic cleavage of PC by bacterial phospholipase C and lipases. Three different bacterial pathways, the choline, glycerol, and fatty acid degradation pathways, are then involved in the degradation of these PC components. Here, we identified five potential FA degradation (Fad related fadBA-operons (fadBA1-5, each encoding 3-hydroxyacyl-CoA dehydrogenase and acyl-CoA thiolase. Through mutagenesis and growth analyses, we showed that three (fadBA145 of the five fadBA-operons are dominant in medium-chain and long-chain Fad. The triple fadBA145 mutant also showed reduced ability to degrade PC in vitro. We have previously shown that by partially blocking Fad, via mutagenesis of fadBA5 and fadDs, we could significantly reduce the ability of P. aeruginosa to replicate on FA and PC in vitro, as well as in the mouse lung. However, no studies have assessed the ability of mutants, defective in choline and/or glycerol degradation in conjunction with Fad, to grow on PC or in vivo. Hence, we constructed additional mutants (ΔfadBA145ΔglpD, ΔfadBA145ΔbetAB, and ΔfadBA145ΔbetABΔglpD significantly defective in the ability to degrade FA, choline, and glycerol and, therefore, PC. The analysis of these mutants in the BALB/c mouse lung infection model showed significant inability to utilize PC in vitro, resulted in decreased replication fitness and competitiveness in vivo compared to the complement strain, although there was little to no variation in typical virulence factor production (e.g., hemolysin, lipase, and protease levels. This further supports the hypothesis that lung surfactant PC serves as an

  11. Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation

    Energy Technology Data Exchange (ETDEWEB)

    Salinero, Kennan Kellaris; Keller, Keith; Feil, William S.; Feil, Helene; Trong, Stephan; Di Bartolo, Genevieve; Lapidus, Alla

    2008-11-17

    Initial interest in Dechloromonas aromatica strain RCB arose from its ability to anaerobically degrade benzene. It is also able to reduce perchlorate and oxidize chlorobenzoate, toluene, and xylene, creating interest in using this organism for bioremediation. Little physiological data has been published for this microbe. It is considered to be a free-living organism. The a priori prediction that the D. aromatica genome would contain previously characterized 'central' enzymes involved in anaerobic aromatic degradation proved to be false, suggesting the presence of novel anaerobic aromatic degradation pathways in this species. These missing pathways include the benzyl succinyl synthase (bssABC) genes (responsible for formate addition to toluene) and the central benzoylCoA pathway for monoaromatics. In depth analyses using existing TIGRfam, COG, and InterPro models, and the creation of de novo HMM models, indicate a highly complex lifestyle with a large number of environmental sensors and signaling pathways, including a relatively large number of GGDEF domain signal receptors and multiple quorum sensors. A number of proteins indicate interactions with an as yet unknown host, as indicated by the presence of predicted cell host remodeling enzymes, effector enzymes, hemolysin-like proteins, adhesins, NO reductase, and both type III and type VI secretory complexes. Evidence of biofilm formation including a proposed exopolysaccharide complex with the somewhat rare exosortase (epsH), is also present. Annotation described in this paper also reveals evidence for several metabolic pathways that have yet to be observed experimentally, including a sulphur oxidation (soxFCDYZAXB) gene cluster, Calvin cycle enzymes, and nitrogen fixation (including RubisCo, ribulose-phosphate 3-epimerase, and nif gene families, respectively). Analysis of the D. aromatica genome indicates there is much to be learned regarding the metabolic capabilities, and life-style, for this microbial

  12. 磁性碳质材料催化糖类制备5-羟甲基糠醛和5-乙氧基甲基糠醛的研究%Magnetic carbonaceous solid acid catalyst for the synthesis of 5-hydroxymethylfurfural and 5-ethoxymethylfurfural from carbohydrates

    Institute of Scientific and Technical Information of China (English)

    姚远; 王海军

    2016-01-01

    A novel magnetically carbonaceous material functionalized with sulfonic acid groups PCM-SO3 H catalyst for the conversion of carbohydrates to liquid biofuels 5-ethoxymethylfurfural (EMF).The effect of DMSO content for the conversion of carbohydrates and the distribution of products was investigated.PCM-SO3 H showed an excellent catalytic activity toward the synthesis of EMF from fructose and HMF.EMF was gained in a high yield of 85.6% by the etherification of 5-hydroxymethylfurfural.When reaction tem-perature was 1 00 ℃,reaction time was 1 0 h,the catalyst amount was 45 mg and solvent(DMSO 1 .5 mL and ethanol 3.5 mL),EMF could also be obtained with a high yield of 61 .8% in the ethanol-DMSO sol-vent system by the one-top conversion of fructose.After reaction,the catalyst could be readily recovered from the reaction mixture solution by an external magnetic field,and reused for several times without loss of its catalytic activity.%制备了一种磺酸化的磁性碳质固体酸催化剂 PCM-SO3 H,用于催化糖类制备液态生物燃料5-乙氧基甲基糠醛(EMF),考察了二甲亚砜在溶剂中的含量对糖类转化和产物分布的影响。结果表明,该催化剂不仅能催化5-羟甲基糠醛(HMF)的醚化,EMF 产率高达85.6%,也能在乙醇-二甲亚砜双溶剂体系下一锅法催化果糖制备 EMF,反应温度100℃,反应时间10 h,催化剂加入量45 mg,溶剂(DMSO 1.5 mL 和乙醇3.5 mL)时,EMF 的收率达61.8%。反应结束后,该催化剂可以在外部磁场条件下从反应混合物中重新获得,且重复使用多次依然保持高的活性。

  13. 磺酸官能化的磁性核壳结构的纳米材料用于果糖脱水制备5-羟甲基糠醛%Nanocoating of magnetic cores with sulfonic acid functionalized shells for the catalytic dehydration of fructose to 5-hydroxymethylfurfural

    Institute of Scientific and Technical Information of China (English)

    张晓辰; 王敏; 王业红; 张超峰; 张哲; 王峰; 徐杰

    2014-01-01

    通过反相微乳液法制备了以Fe3O4为核,磺酸官能化的硅基材料为壳层的磁性酸性催化剂.首先制备纳米Fe3O4磁核,然后涂层包覆苯基修饰的纳米级硅层,最后进行苯基磺化修饰,制得固体酸催化剂Fe3O4@Si/Ph-SO3H.在果糖脱水制备5-羟甲基糠醛反应中,该催化剂表现出较好的催化活性,优于传统催化剂A-15,且与均相无机酸催化活性相当.当采用二甲基亚砜作溶剂,在110 oC下反应3 h,果糖转化率达到99%,5-羟甲基糠醛收率为82%.另外,该催化剂经磁法回收后可多次重复使用.%A magnetically recyclable acid catalyst composed of an Fe3O4 core and sulfonic acid functionalized silica shell has been prepared using the reverse microemulsion method. The Fe3O4 core was coated with a phenyl modified silica shell nanolayer, and the phenyl groups were subsequently sulfonated to generate a solid sulfonic acid catalyst. The resulting acid catalyst showed higher activity than the conventional A-15 catalyst and comparable activity to several homogeneous sulfonic acid catalysts for the dehydration of fructose to 5-hydroxymethylfurfural (HMF). This process gave a fructose conversion of 99%with an HMF yield of 82%following 3 h in dimethylsulfoxide at 110 °C. Fur-thermore, the catalyst could be magnetically separated and recycled several times without losing its activity.

  14. 离子液体中Lewis酸催化葡萄糖和果糖脱水制备5-羟甲基呋喃甲醛%Dehydration of Glucose and Fructose into 5-Hydroxymethylfurfural Catalyzed by Lewis Acid in Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    田玉奎; 邓晋; 潘涛; 郭庆祥; 傅尧

    2011-01-01

    在离子液体中采用不同的Lewis酸催化葡萄糖和果糖脱水制备5-羟甲基呋喃甲醛(5-HMF).结果表明,CrCln和SnCln均可高效催化葡萄糖转化为5-HMF.另外,Lewis酸的酸性越强,其催化果糖转化为5-HMF的产率越高.镧系金属氯化物在反应中表现出较好的催化活性和产物选择性.同时还研究了离子液体结构对催化反应的影响.结果表明,咪唑型离子液体在葡萄糖转化为5-HMF的反应中表现出明显的奇偶效应,即离子液体支链碳原予数为偶数时,5-HMF产率较高;而在果糖转化为5-HMF的反应中,离子液体的支链烷基长度越短,5-HMF产率越高.在离子液体[C2MIM]Br(溴化1-乙基-3-甲基咪唑)中,SnCl2催化葡萄糖脱水时5-HMF收率为65%,而ErCl3催化果糖得到的5-HMF收率可达92%.%A variety of Lewis acids have been examined for the transformation of glucose and fructose into 5-hydroxymethylfurfural (5-HMF) in ionic liquids (ILs). SnCln and CrCln are effective catalysts for the isomerization, and Lewis acids with strong acidity can facili tate the dehydration of fructose. The influence of ILs structure, including the length of alkyl side chain and halide anions, on the conversion was also studied. A distinct odd-even carbon-atom-number effect is observed in the conversion of glucose to 5-HMF and the imidazolium bromides with short alkyl side-chains can provide a higher yield of 5-HMF from fructose. In the presence of 1-ethyl-3-methylimidazolium bromide ([C2MIM]Br) and SnCl2, the yields of 5-HMF are 65% and 73% from glucose and fructose, respectively.

  15. 固体酸WO3/ZrO2催化果糖脱水合成5-羟甲基糠醛%WO3/ZrO2 for fructose dehydration to 5-hydroxymethylfurfural as a solid acid catalyst

    Institute of Scientific and Technical Information of China (English)

    刘彦丽; 王福余; 王崇; 赵振波

    2014-01-01

    用共沉淀-热回流处理法制备了系列WO3/ZrO2固体酸催化剂,通过调节W与Zr的摩尔比优化其对果糖脱水制备5-羟甲基糠醛(5-HMF)的催化活性。利用X射线衍射(XRD)、N2吸脱附、氨气程序升温脱附(NH3-TPD)对材料的结构和酸性质进行了表征,并在以二甲基亚砜(DMSO)为溶剂、果糖为原料的催化体系中,考察催化剂的用量、反应时间、反应温度等对5-HMF收率的影响。研究发现,热回流处理大大增加了样品的比表面积,增强了样品的酸强度,当n(W)∶n(Zr)=0.1∶1时,样品比表面积最大,催化活性最好,以其为催化剂,在130℃下反应3 h条件下,5-HMF收率最高可达80.29%。%Catalytic dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) was studied and improved by synthesizing series of solid acid catalyst WO3/ZrO2 with different mole ratio of W to Zr using co-precipitation with hot reflux method. The structure and properties of the catalysts thus synthesized were investigated by X-ray diffraction(XRD),N2 sorption,temperature -programmed desorption of (NH3-TPD),and then the influence of temperature,mass ration of fructose/catalyst and reaction time on the yield of 5-HMF from fructose were studied in dimethyl sulfoxide. These studies showed that specific surface area and acid strength of the catalysts were increased greatly by hot reflux method,and an optimized 5-HMF yield of 80.29%was obtained with 3 h at 130 ℃ in the presence of the sample WO3/ZrO2 with W-Zr mole ratio of 0.1∶1,which had a largest specific surface area and best catalytic activity.

  16. 对-香豆酸和绿原酸对美拉德反应体系中5-羟甲基糠醛形成的影响%Effects ofp-Coumaric Acid and Chlorogenic Acid on Formation of 5-Hydroxymethylfurfural in Different Maillard Reaction Systems

    Institute of Scientific and Technical Information of China (English)

    江姗姗; 梁恩; 于淼; 欧仕益

    2012-01-01

    The effects ofp-coumaric acid and chlorogenic acid on the formation of 5-hydroxymethylfurfural (5-HMF) was investigated in the Maillard reaction models of glucose with glutamate, lysine, glycine, and cysteine respectively. The results showed that the production of 5-HMF in different amino acid-glucose reaction systems decreased in the order: glutamate, lysine, glycine and cysteine. Both phenolic acids played a dual role of inhibition and promotion in the formation of 5-HMF in Maillard reaction systems. Various concentrations of phenolic acids had different effects on the formation of 5-HMF and constant concentrations in different Maillard reaction systems also revealed different effects on the formation of 5-HMF.%以谷氨酸、赖氨酸、甘氨酸、半胱氨酸分别与葡萄糖反应构建美拉德反应体系,研究5-羟甲基糠醛(5-HMF)的形成量随时间的变化规律及对-香豆酸和绿原酸对5.HMF形成量的影响。结果表明:在相同反应时间内,模拟体系中5-HMF形成量由高到低排列依次是:谷氨酸-葡萄糖模拟体系〉赖氨酸-葡萄糖模拟体系〉甘氨酸.葡萄糖模拟体系〉半胱氨酸-葡萄糖模拟体系;对-香豆酸、绿原酸对美拉德反应中5-HMF形成均表现出抑制和促进的“双重作用”;不同质量浓度的对-香豆酸、绿原酸对5-HMF的影响趋势不同,相同质量浓度的同种酚酸对不同模拟反应体系中5-HMF的影响也有差异。

  17. Degradation of 2,4-dihydroxibenzoic acid by vacuum UV process in aqueous solution: Kinetic, identification of intermediates and reaction pathway

    Energy Technology Data Exchange (ETDEWEB)

    Azrague, Kamal [Laboratoire IMRCP, CNRS UMR 5623, University of Toulouse, 118 route de Narbonne, 31062 Toulouse (France); Department for Water and Environment, SINTEF, Klaebuveien 153, Trondheim 7465 (Norway); Pradines, Vincent; Bonnefille, Eric [Laboratoire IMRCP, CNRS UMR 5623, University of Toulouse, 118 route de Narbonne, 31062 Toulouse (France); Laboratoire LCC, CNRS, 205 route de Narbonne, F31077 Toulouse Cedex 4 (France); Claparols, Catherine [Laboratoire LCC, CNRS, 205 route de Narbonne, F31077 Toulouse Cedex 4 (France); Universite de Toulouse, UPS, Service Commun de Spectrometrie de Masse, 118 route de Narbonne, F31062 Toulouse Cedex 9 (France); Maurette, Marie-Therese [Laboratoire IMRCP, CNRS UMR 5623, University of Toulouse, 118 route de Narbonne, 31062 Toulouse (France); Benoit-Marquie, Florence, E-mail: florence@chimie.ups-tlse.fr [Laboratoire IMRCP, CNRS UMR 5623, University of Toulouse, 118 route de Narbonne, 31062 Toulouse (France)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer Degradation of 2,4-dihydroxybenzoic acid (DHBA) by vacuum UV photolysis of water. Black-Right-Pointing-Pointer V-UV Xe-excimer lamps produced essentially hydroxyl radicals (HO Degree-Sign ). Black-Right-Pointing-Pointer Identification of all intermediates formed allowed us to propose a reaction pathway. Black-Right-Pointing-Pointer This reaction pathway showed that DHBA reacts differently with HO Degree-Sign and h+. Black-Right-Pointing-Pointer DHBA would be used as a probe to determine which of these entities were involved. - Abstract: 2,4-Dihydroxybenzoic acid (2,4-DHBA) is found frequently as a pollutant in natural waters and represents a threat to water quality because it is a precursor to the formation of quinones which are highly toxic. The degradation of 2,4-DHBA using the vacuum UV photolysis of water has been investigated. Irradiation was carried out in an annular photoreactor equipped with a Xe-excimer lamp situated in the centre and emitting at 172 nm. The degradation kinetic followed a pseudo first order and the reaction has been found to be very heterogeneous, especially at low concentration. Impacts of oxygen or temperature have also been investigated but no effect has been shown. LC-MS and HPLC-UV combined with other analytical techniques allowed the identification of the formation of trihydroxybenzoiec acids and trihydroxybenzenes which underwent a ring opening, conducting to the formation of aliphatic products named {alpha}, {beta}, {delta} and {gamma}. These products were in turn degraded successively into maleiec acid, malic and succinic acid, malonic acid, glyoxalic acid and oxalic acid before reaching the complete mineralization in about 180 min. The proposed reaction pathway has shown to be very different from the one observed for the TiO{sub 2} photocatalysis which involves only holes (h{sup +}) without any formation of aromatic intermediates. The different behaviours of 2,4-DHBA towards the h

  18. Catalytic degradation of recalcitrant pollutants by Fenton-like process using polyacrylonitrile-supported iron (II) phthalocyanine nanofibers: Intermediates and pathway.

    Science.gov (United States)

    Zhu, Zhexin; Chen, Yi; Gu, Yan; Wu, Fei; Lu, Wangyang; Xu, Tiefeng; Chen, Wenxing

    2016-04-15

    Iron (II) phthalocyanine (FePc) molecules were isolated in polyacrylonitrile (PAN) nanofibers by electrospinning to prevent the formation of dimers and oligomers. Carbamazepine (CBZ) and Rhodamine B (RhB) degradation was investigated during a Fenton-like process with FePc/PAN nanofibers. Classical quenching tests with isopropanol and electron paramagnetic resonance tests with 5,5-dimethyl-pyrroline-oxide as spin-trapping agent were performed to determine the formation of active species during hydrogen peroxide (H2O2) decomposition by FePc/PAN nanofibers. After eight recycles for CBZ degradation over the FePc/PAN nanofibers/H2O2 system, the removal ratios of CBZ remained at 99%. Seven by-products of RhB and twelve intermediates of CBZ were identified using ultra-performance liquid chromatography and high-resolution mass spectrometry. Pathways of CBZ and RhB degradation were proposed based on the identified intermediates. As the reaction proceeded, all CBZ and RhB aromatic nucleus intermediates decreased and were transformed to small acids, but also to potentially toxic epoxide-containing intermediates and acridine, because of the powerful oxidation ability of •OH in the catalytic system. PMID:26949842

  19. Comparative genomic analysis and benzene, toluene, ethylbenzene, and o-, m-, and p-xylene (BTEX) degradation pathways of Pseudoxanthomonas spadix BD-a59.

    Science.gov (United States)

    Choi, Eun Jin; Jin, Hyun Mi; Lee, Seung Hyeon; Math, Renukaradhya K; Madsen, Eugene L; Jeon, Che Ok

    2013-01-01

    Pseudoxanthomonas spadix BD-a59, isolated from gasoline-contaminated soil, has the ability to degrade all six BTEX (benzene, toluene, ethylbenzene, and o-, m-, and p-xylene) compounds. The genomic features of strain BD-a59 were analyzed bioinformatically and compared with those of another fully sequenced Pseudoxanthomonas strain, P. suwonensis 11-1, which was isolated from cotton waste compost. The genome of strain BD-a59 differed from that of strain 11-1 in many characteristics, including the number of rRNA operons, dioxygenases, monooxygenases, genomic islands (GIs), and heavy metal resistance genes. A high abundance of phage integrases and GIs and the patterns in several other genetic measures (e.g., GC content, GC skew, Karlin signature, and clustered regularly interspaced short palindromic repeat [CRISPR] gene homology) indicated that strain BD-a59's genomic architecture may have been altered through horizontal gene transfers (HGT), phage attack, and genetic reshuffling during its evolutionary history. The genes for benzene/toluene, ethylbenzene, and xylene degradations were encoded on GI-9, -13, and -21, respectively, which suggests that they may have been acquired by HGT. We used bioinformatics to predict the biodegradation pathways of the six BTEX compounds, and these pathways were proved experimentally through the analysis of the intermediates of each BTEX compound using a gas chromatograph and mass spectrometry (GC-MS). The elevated abundances of dioxygenases, monooxygenases, and rRNA operons in strain BD-a59 (relative to strain 11-1), as well as other genomic characteristics, likely confer traits that enhance ecological fitness by enabling strain BD-a59 to degrade hydrocarbons in the soil environment. PMID:23160122

  20. HUWE1 interacts with BRCA1 and promotes its degradation in the ubiquitin–proteasome pathway (Biochemical and Biophysical Research Communications, v. 444 issue 3)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaozhen [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China); Lu, Guang; Li, Li; Yi, Juan; Yan, Kaowen; Wang, Yaqing; Zhu, Baili; Kuang, Jingyu; Lin, Ming; Zhang, Sha [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Shao, Genze, E-mail: gzshao@bjmu.edu.cn [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China)

    2014-02-14

    Highlights: • The 2000–2634 aa region of HUWE1 mediates the interaction with BRCA1 degron. • HUWE1 promotes the degradation of BRCA1 through the ubiquitin–proteasome pathway. • HUWE1 expression is inversely correlated with BRCA1 in breast cancer cells. • RNAi inhibition of HUWE1 confers increased resistance of MCF-10F cells to IR and MMC. - Abstract: The cellular BRCA1 protein level is essential for its tumor suppression activity and is tightly regulated through multiple mechanisms including ubiquitn–proteasome system. E3 ligases are involved to promote BRCA1 for ubiquitination and degradation. Here, we identified HUWE1/Mule/ARF-BP1 as a novel BRCA1-interacting protein involved in the control of BRCA1 protein level. HUWE1binds BRCA1 through its N-terminus degron domain. Depletion of HUWE1 by siRNA-mediated interference significantly increases BRCA1 protein levels and prolongs the half-life of BRCA1. Moreover, exogenous expression of HUWE1 promotes BRCA1 degradation through the ubiquitin–proteasome pathway, which could explain an inverse correlation between HUWE1 and BRCA1 levels in MCF10F, MCF7 and MDA-MB-231 breast cancer cells. Consistent with a functional role for HUWE1 in regulating BRCA1-mediated cellular response to DNA damage, depletion of HUWE1 by siRNA confers increased resistance to ionizing radiation and mitomycin. These data indicate that HUWE1 is a critical negative regulator of BRCA1 and suggest a new molecular mechanism for breast cancer pathogenesis.

  1. HUWE1 interacts with BRCA1 and promotes its degradation in the ubiquitin–proteasome pathway (Biochemical and Biophysical Research Communications, v. 444, isse 4)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaozhen [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China); Lu, Guang; Li, Li; Yi, Juan; Yan, Kaowen; Wang, Yaqing; Zhu, Baili; Kuang, Jingyu; Lin, Ming; Zhang, Sha [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Shao, Genze, E-mail: gzshao@bjmu.edu.cn [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China)

    2014-02-21

    Highlights: • The 2000–2634aa region of HUWE1 mediates the interaction with BRCA1 degron. • HUWE1 promotes the degradation of BRCA1 through the ubiquitin–proteasome pathway. • HUWE1 expression is inversely correlated with BRCA1 in breast cancer cells. • RNAi inhibition of HUWE1 confers increased resistance of MCF-10F cells to IR and MMC. - Abstract: The cellular BRCA1 protein level is essential for its tumor suppression activity and is tightly regulated through multiple mechanisms including ubiquitn–proteasome system. E3 ligases are involved to promote BRCA1 for ubiquitination and degradation. Here, we identified HUWE1/Mule/ARF-BP1 as a novel BRCA1-interacting protein involved in the control of BRCA1 protein level. HUWE1 binds BRCA1 through its N-terminus degron domain. Depletion of HUWE1 by siRNA-mediated interference significantly increases BRCA1 protein levels and prolongs the half-life of BRCA1. Moreover, exogenous expression of HUWE1 promotes BRCA1 degradation through the ubiquitin–proteasome pathway, which could explain an inverse correlation between HUWE1 and BRCA1 levels in MCF10F, MCF7 and MDA-MB-231 breast cancer cells. Consistent with a functional role for HUWE1 in regulating BRCA1-mediated cellular response to DNA damage, depletion of HUWE1 by siRNA confers increased resistance to ionizing radiation and mitomycin. These data indicate that HUWE1 is a critical negative regulator of BRCA1 and suggest a new molecular mechanism for breast cancer pathogenesis.

  2. Involvement of Bcl-xL degradation and mitochondrial-mediated apoptotic pathway in pyrrolizidine alkaloids-induced apoptosis in hepatocytes

    International Nuclear Information System (INIS)

    Pyrrolizidine alkaloids (PAs) are natural hepatotoxins with worldwide distribution in more than 6000 high plants including medicinal herbs or teas. The aim of this study is to investigate the signal pathway involved in PAs-induced hepatotoxicity. Our results showed that clivorine, isolated from Ligularia hodgsonii Hook, decreased cell viability and induced apoptosis in L-02 cells and mouse hepatocytes. Western-blot results showed that clivorine induced caspase-3/-9 activation, mitochondrial release of cytochrome c and decreased anti-apoptotic Bcl-xL in a time (8-48 h)- and concentration (1-100 μM)-dependent manner. Furthermore, inhibitors of pan-caspase, caspase-3 and caspase-9 significantly inhibited clivorine-induced apoptosis and rescued clivorine-decreased cell viability. Polyubiquitination of Bcl-xL was detected after incubation with 100 μM clivorine for 40 h in the presence of proteasome specific inhibitor MG132, indicating possible degradation of Bcl-xL protein. Furthermore, pretreatment with MG132 or calpain inhibitor I for 2 h significantly enhanced clivorine-decreased Bcl-xL level and cell viability. All the other tested PAs such as senecionine, isoline and monocrotaline decreased mouse hepatocytes viability in a concentration-dependent manner. Clivorine (10 μM) induced caspase-3 activation and decreased Bcl-xL was also confirmed in mouse hepatocytes. Meanwhile, another PA senecionine isolated from Senecio vulgaris L also induced apoptosis, caspase-3 activation and decreased Bcl-xL in mouse hepatocytes. In conclusion, our results suggest that PAs may share the same hepatotoxic signal pathway, which involves degradation of Bcl-xL protein and thus leading to the activation of mitochondrial-mediated apoptotic pathway

  3. Synthesized TiO2/ZSM-5 composites used for the photocatalytic degradation of azo dye: Intermediates, reaction pathway, mechanism and bio-toxicity

    Science.gov (United States)

    Zhou, Kefu; Hu, Xin-Yan; Chen, Bor-Yann; Hsueh, Chung-Chuan; Zhang, Qian; Wang, Jiajie; Lin, Yu-Jung; Chang, Chang-Tang

    2016-10-01

    In this study, a one-step solid dispersion method was used to synthesize titanium dioxide (TiO2)/Zeolite Socony Mobil-5 (ZSM-5) composites with substantially reduced time and energy consumption. A degradation efficiency of more than 95% was achieved within 10 min using 50% PTZ (synthesized TiO2/ZSM-5 composites with TiO2 contents of 50 wt% loaded on ZSM-5) at pH 7 and 25 °C. The possible degradation pathway of azo-dye Reactive Black 5 (RB5) was investigated using gas chromatography-mass spectrometry and ion chromatography (IC). The bonds between the N atoms and naphthalene groups are likely attacked first and cleaved by hydroxyl radicals, ultimately resulting in the decolorization and mineralization of the azo dye. A comparative assessment of the characteristics of abiotic and biotic dye decolorization was completed. In addition, the toxicity effects of the degradation intermediates of azo-dye RB5 on cellular respiratory activity were analyzed. The bio-toxicity results showed that the decay rate constants of CO2 production from the azo-dye RB5 samples at different degradation times increased initially and subsequently decreased, indicating that intermediates of higher toxicity could adhere to the catalyst surface and gradually destroyed by further photocatalytic oxidation. Additionally, EDTA (hole scavengers) and t-BuOH (radical scavengers) were used to detect the main active oxidative species in the system. The results showed that the hydroxyl radicals are the main oxidation species in the photocatalytic process.

  4. Foot-and-mouth disease virus structural protein VP3 degrades Janus kinase 1 to inhibit IFN-γ signal transduction pathways.

    Science.gov (United States)

    Li, Dan; Wei, Jin; Yang, Fan; Liu, Hua-Nan; Zhu, Zi-Xiang; Cao, Wei-Jun; Li, Shu; Liu, Xiang-Tao; Zheng, Hai-Xue; Shu, Hong-Bing

    2016-01-01

    Foot-and-mouth disease is a highly contagious viral disease of cloven-hoofed animals that is caused by foot-and-mouth disease virus (FMDV). To replicate efficiently in vivo, FMDV has evolved methods to circumvent host antiviral defense mechanisms, including those induced by interferons (IFNs). Previous research has focused on the effect of FMDV L(pro) and 3C(pro) on type I IFNs. In this study, FMDV VP3 was found to inhibit type II IFN signaling pathways. The overexpression of FMDV VP3 inhibited the IFN-γ-triggered phosphorylation of STAT1 at Tyr701 and the subsequent expression of downstream genes. Mechanistically, FMDV VP3 interacted with JAK1/2 and inhibited the tyrosine phosphorylation, dimerization and nuclear accumulation of STAT1. FMDV VP3 also disrupted the assembly of the JAK1 complex and degraded JAK1 but not JAK2 via a lysosomal pathway. Taken together, the results reveal a novel mechanism used by which FMDV VP3 counteracts the type II IFN signaling pathways. PMID:26901336

  5. Microbial degradation of furanic compounds: biochemistry, genetics, and impact

    NARCIS (Netherlands)

    Wierckx, N.; Koopman, F.; Ruijssenaars, H.J.; De Winde. J.H.

    2011-01-01

    Microbial metabolism of furanic compounds, especially furfural and 5-hydroxymethylfurfural (HMF), is rapidly gaining interest in the scientific community. This interest can largely be attributed to the occurrence of toxic furanic aldehydes in lignocellulosic hydrolysates. However, these compounds ar

  6. Adsorption and Photocatalytic Decomposition of the -Blocker Metoprolol in Aqueous Titanium Dioxide Suspensions: Kinetics, Intermediates, and Degradation Pathways

    OpenAIRE

    Violette Romero; Pilar Marco; Jaime Giménez; Santiago Esplugas

    2013-01-01

    This study reports the photocatalytic degradation of the β-blocker metoprolol (MET) using TiO2 suspended as catalyst. A series of photoexperiments were carried out by a UV lamp, emitting in the 250–400 nm range, providing information about the absorption of radiation in the photoreactor wall. The influence of the radiation wavelength on the MET photooxidation rate was investigated using a filter cutting out wavelengths shorter than 280 nm. Effects of photolysis and adsorption at different ini...

  7. Murrayafoline A attenuates the Wnt/{beta}-catenin pathway by promoting the degradation of intracellular {beta}-catenin proteins

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyuk; Gwak, Jungsug; Cho, Munju; Ryu, Min-Jung [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Lee, Jee-Hyun; Kim, Sang Kyum; Kim, Young Ho [College of Pharmacy, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Gye Won [Department of Pharmaceutical Engineering, Konyang University, Nonsan 320-711 (Korea, Republic of); Yun, Mi-Young [Department of Beauty Health Care, Daejeon University, Daejeon 305-764 (Korea, Republic of); Cuong, Nguyen Manh [Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Shin, Jae-Gook [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of); Song, Gyu-Yong, E-mail: gysong@cnu.ac.kr [College of Pharmacy, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Oh, Sangtaek, E-mail: ohsa@inje.ac.kr [PharmacoGenomics Research Center, Inje University, Busan 614-735 (Korea, Republic of)

    2010-01-01

    Molecular lesions in Wnt/{beta}-catenin signaling and subsequent up-regulation of {beta}-catenin response transcription (CRT) occur frequently during the development of colon cancer. To identify small molecules that suppress CRT, we screened natural compounds in a cell-based assay for detection of TOPFalsh reporter activity. Murrayafoline A, a carbazole alkaloid isolated from Glycosmis stenocarpa, antagonized CRT that was stimulated by Wnt3a-conditioned medium (Wnt3a-CM) or LiCl, an inhibitor of glycogen synthase kinase-3{beta} (GSK-3{beta}), and promoted the degradation of intracellular {beta}-catenin without altering its N-terminal phosphorylation at the Ser33/37 residues, marking it for proteasomal degradation, or the expression of Siah-1, an E3 ubiquitin ligase. Murrayafoline A repressed the expression of cyclin D1 and c-myc, which is known {beta}-catenin/T cell factor (TCF)-dependent genes and thus inhibited the proliferation of various colon cancer cells. These findings indicate that murrayafoline A may be a potential chemotherapeutic agent for use in the treatment of colon cancer.

  8. Metabolism of 2-Chloro-4-Nitroaniline via Novel Aerobic Degradation Pathway by Rhodococcus sp. Strain MB-P1

    OpenAIRE

    Fazlurrahman Khan; Deepika Pal; Surendra Vikram; Swaranjit Singh Cameotra

    2013-01-01

    2-chloro-4-nitroaniline (2-C-4-NA) is used as an intermediate in the manufacture of dyes, pharmaceuticals, corrosion inhibitor and also used in the synthesis of niclosamide, a molluscicide. It is marked as a black-listed substance due to its poor biodegradability. We report biodegradation of 2-C-4-NA and its pathway characterization by Rhodococcus sp. strain MB-P1 under aerobic conditions. The strain MB-P1 utilizes 2-C-4-NA as the sole carbon, nitrogen, and energy source. In the growth medium...

  9. The type II collagen fragments Helix-II and CTX-II reveal different enzymatic pathways of human cartilage collagen degradation

    DEFF Research Database (Denmark)

    Charni-Ben Tabassi, N; Desmarais, S; Jensen, Anne-Christine Bay;

    2008-01-01

    human recombinant cathepsins (Cats) and matrix-metalloproteases (MMPs). Next, we analyzed the spontaneous release of Helix-II and CTX-II from cartilage sections of patients with knee OA who were immediately deep frozen after joint replacement to preserve endogenous enzyme activity until assay. Cartilage...... that they may be generated through different collagenolytic pathways. In this study we analyzed the release of Helix-II and CTX-II from human cartilage collagen by the proteinases reported to play a role in cartilage degradation. METHODS: In vitro, human articular cartilage extract was incubated with activated...... sections were then incubated for up to 84h in the presence or absence of E-64 and GM6001, inhibitors of cysteine proteases and MMPs, respectively. RESULTS: In vitro, Cats K, L and S generated large amount of Helix-II, but not CTX-II. Cat B generated CTX-II fragment, but destroyed Helix-II immunoreactivity...

  10. Carbazole-degradative IncP-7 plasmid pCAR1.2 is structurally unstable in Pseudomonas fluorescens Pf0-1, which accumulates catechol, the intermediate of the carbazole degradation pathway.

    Science.gov (United States)

    Takahashi, Yurika; Shintani, Masaki; Li, Li; Yamane, Hisakazu; Nojiri, Hideaki

    2009-06-01

    We determined the effect of the host on the function and structure of the nearly identical IncP-7 carbazole-degradative plasmids pCAR1.1 and pCAR1.2. We constructed Pseudomonas aeruginosa PAO1(pCAR1.2) and P. fluorescens Pf0-1Km(pCAR1.2) and compared their growth on carbazole- and succinate-containing media with that of P. putida KT2440(pCAR1.1). We also assessed the stability of the genetic structures of the plasmids in each of the three hosts. Pf0-1Km(pCAR1.2) showed dramatically delayed growth when carbazole was supplied as the sole carbon source, while the three strains grew at nearly the same rate on succinate. Among the carbazole-grown Pf0-1Km(pCAR1.2) cells, two types of deficient strains appeared and dominated the population; such dominance was not observed in the other two strains or for succinate-grown Pf0-1Km(pCAR1.2). Genetic analysis showed that the two deficient strains possessed pCAR1.2 derivatives in which the carbazole-degradative car operon was deleted or its regulatory gene, antR, was deleted by homologous recombination between insertion sequences. From genomic information and quantitative reverse transcription-PCR analyses of the genes involved in carbazole mineralization by Pf0-1Km(pCAR1.2), we found that the cat genes on the chromosome of Pf0-1Km, which are necessary for the degradation of catechol (a toxic intermediate in the carbazole catabolic pathway), were not induced in the presence of carbazole. The resulting accumulation of catechol may have enabled the strain that lost its carbazole-degrading ability to have overall higher fitness than the wild-type strain. These results suggest that the functions of the chromosomal genes contributed to the selection of plasmid derivatives with altered structures.

  11. 右旋糖酐40葡萄糖注射液 pH 值与5-羟甲基糠醛、糠醛含量的相关性分析%Correlation Analysis of Furfural, 5-hydroxymethylfurfural Content and pH Value of Dextran 40 and Glucose Injection

    Institute of Scientific and Technical Information of China (English)

    郭欢迎; 耿庆光; 王嫦鹤

    2015-01-01

    Objective To analyze the correlation of furfural, 5-hydroxymethylfurfural (5-HMF) content and pH value of dextran 40 and glucose injection, and to provide reasonable suggestions for the production, transportation and use. Methods High performance liquid chromatography method was used to determine the content of 5- HMF and furfural of 90 batches of dextran 40 and glucose Injection. The pH value of the solution was determined by acidometer. Correlation of furfural, 5-HMF content and pH value was analyzed by SPASS 17.0. The destructive tests were carried out to verify the conclusion. Results There is a negative correlation between the value of pH and content of 5- HMF, and the content of furfural was positively correlated with 5- HMF. Destructive test results show that, the decrease of pH value will lead to the generation of 5- HMF and furfural. Conclusion Through the strict control of pH value, the stability of dextran 40 and glucose injection can be increased. And the increase 5- HMF and furfural content of the preparation could be suppressed too.%目的:对右旋糖酐40葡萄糖注射液的 pH 值与5-羟甲基糠醛、糠醛含量进行相关性分析,为其生产、运输和使用提供合理化建议。方法采用高效液相色谱法对所有90批右旋糖酐40葡萄糖注射液中的5-羟甲基糠醛、糠醛进行测定,同时采用酸度计测定溶液的 pH 值,并用 SPASS 17.0对测定结果的 pH 值与5-羟甲基糠醛、糠醛进行相关性分析,并采用破坏性试验对结论进行验证。结果右旋糖酐40葡萄糖注射液的 pH 值与5-羟甲基糠醛的含量负相关,5-羟甲基糠醛的含量与糠醛的含量呈正相关。破坏性试验结果证明,pH 值的降低会导致5-羟甲基糠醛和糠醛的生成。结论通过严格控制该制剂的 pH 值,可以增加右旋糖酐40葡萄糖注射液的稳定性,抑制制剂中5-羟甲基糠醛和糠醛含量的增加。

  12. 五味子提取过程中5-羟甲基糠醛的变化规律及影响因素研究%Research of the Variation Rule and Influencing Factors of 5-hydroxymethylfurfural in the Extraction Pro-cess of Schisandra chinensis

    Institute of Scientific and Technical Information of China (English)

    李越; 慕升君; 李德坤; 杨悦武; 余伯阳; 叶正良; 鞠爱春

    2015-01-01

    目的:探究五味子药材提取过程中5-羟甲基糠醛(5-HMF)的含量变化规律和影响因素,提高五味子提取物的监控质量。方法:采用高效液相色谱法测定五味子药材提取过程(煎煮、减压浓缩、醇沉、减压干燥、调碱)中各提取液中5-HMF含量,找出其含量变化规律,并针对5-HMF含量明显降低的减压干燥过程,研究该过程中干燥温度和时间对5-HMF含量的影响,同时比较减压干燥和冷冻干燥对5-HMF含量的影响变化。结果:五味子提取过程中5-HMF的含量变化趋势为药材煎煮的过程中产生大量5-HMF,浓缩时5-HMF的含量升高,醇沉和三次浓缩液减压干燥时5-HMF的含量均降低,调碱时5-HMF的含量基本不变;减压干燥时随干燥温度的升高和时间的延长,5-HMF含量降低;冷冻干燥对5-HMF含量的降低效果不如减压干燥。结论:建议适当采用较高的温度减压干燥五味子三次浓缩液,可得到5-HMF含量更低的五味子提取物,提高五味子提取物的质量。%OBJECTIVE:To explore the content variation rule and influencing factors of 5-hydroxymethylfurfural(5-HMF)in the extraction process of the herbs Schisandra chinensis and improve the quality of monitoring the extract of Schisandra chinensis. METHODS:High performance liquid chromatography was adopted to determine the contents of 5-HMF in the extracts during the extraction process (decoction,vacuum concentration,alcohol precipitation,vacuum drying,alkali adjustment),and the content variation rule was found out. For vacuum drying during which the content of 5-HMF reduced obviously,the effects of the tempera-ture and time of drying on the content of 5-HMF were studied,and the effects of vacuum drying and freeze drying on the 5-HMF contents were compared. RESULTS:The content variation trend in the extraction process of Schisandra chinensis was as follows as a large amount of 5-HMF was produced in the

  13. Heterogeneous photo-Fenton decolorization of Orange II over Al-pillared Fe-smectite: Response surface approach, degradation pathway, and toxicity evaluation

    International Nuclear Information System (INIS)

    Highlights: • Al-pillared Fe-smectite was synthesized and used as the photo-Fenton catalyst. • Response surface methodology was used to study the effects of reaction parameters. • The main intermediate products were identified by GC–MS technique. • A possible degradation pathway of Orange II was proposed. • All the generated products of Orange II were less toxic than the original dye. - Abstract: A ferric smectite clay material was synthesized and further intercalated with Al2O3 pillars for the first time with the aim of evaluating its ability to be used as heterogeneous catalyst for the photo-Fenton decolorization of azo dye Orange II. UV irradiation was found to enhance the activity of the catalyst in the heterogeneous photo-Fenton process. Catalyst loading of 0.5 g/L and hydrogen peroxide concentration of 13.5 mM yielded a remarkable color removal, accompanied by excellent catalyst stability. The decolorization of Orange II followed the pseudo-first-order kinetics for initial dye concentrations from 20 to 160 mg/L. The central composite design (CCD) based on the response surface methodology (RSM) was applied to evaluate the effects of several operating parameters, namely initial pH, catalyst loading and hydrogen peroxide concentration, on the decolorization efficiency. The RSM model was derived and the response surface plots were developed based on the results. Moreover, the main intermediate products were separated and identified using gas chromatography–mass spectrometry (GC–MS) and a possible degradation pathway was proposed accordingly. The acute toxicity experiments illustrated that the Daphniamagna immobilization rate continuously decreased during 150 min reaction, indicating that the effluent was suitable for sequential biological treatment

  14. Heterogeneous photo-Fenton decolorization of Orange II over Al-pillared Fe-smectite: Response surface approach, degradation pathway, and toxicity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huiyuan; Li, Yanli [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Xiang, Luojing [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Université de Poitiers, UMR CNRS 7285, IC2MP, ENSIP, B1, 1 rue Marcel Doré, TSA 41105, Poitiers 86073 Cedex 9 (France); Huang, Qianqian; Qiu, Juanjuan [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Zhang, Hui, E-mail: eeng@whu.edu.cn [Department of Environmental Engineering, Wuhan University, Wuhan 430079 (China); Sivaiah, Matte Venkata; Baron, Fabien; Barrault, Joel; Petit, Sabine [Université de Poitiers, UMR CNRS 7285, IC2MP, ENSIP, B1, 1 rue Marcel Doré, TSA 41105, Poitiers 86073 Cedex 9 (France); Valange, Sabine, E-mail: sabine.valange@univ-poitiers.fr [Université de Poitiers, UMR CNRS 7285, IC2MP, ENSIP, B1, 1 rue Marcel Doré, TSA 41105, Poitiers 86073 Cedex 9 (France)

    2015-04-28

    Highlights: • Al-pillared Fe-smectite was synthesized and used as the photo-Fenton catalyst. • Response surface methodology was used to study the effects of reaction parameters. • The main intermediate products were identified by GC–MS technique. • A possible degradation pathway of Orange II was proposed. • All the generated products of Orange II were less toxic than the original dye. - Abstract: A ferric smectite clay material was synthesized and further intercalated with Al{sub 2}O{sub 3} pillars for the first time with the aim of evaluating its ability to be used as heterogeneous catalyst for the photo-Fenton decolorization of azo dye Orange II. UV irradiation was found to enhance the activity of the catalyst in the heterogeneous photo-Fenton process. Catalyst loading of 0.5 g/L and hydrogen peroxide concentration of 13.5 mM yielded a remarkable color removal, accompanied by excellent catalyst stability. The decolorization of Orange II followed the pseudo-first-order kinetics for initial dye concentrations from 20 to 160 mg/L. The central composite design (CCD) based on the response surface methodology (RSM) was applied to evaluate the effects of several operating parameters, namely initial pH, catalyst loading and hydrogen peroxide concentration, on the decolorization efficiency. The RSM model was derived and the response surface plots were developed based on the results. Moreover, the main intermediate products were separated and identified using gas chromatography–mass spectrometry (GC–MS) and a possible degradation pathway was proposed accordingly. The acute toxicity experiments illustrated that the Daphniamagna immobilization rate continuously decreased during 150 min reaction, indicating that the effluent was suitable for sequential biological treatment.

  15. Decolorization of azo dye C.I. Reactive Black 5 by ozonation in aqueous solution: influencing factors, degradation products, reaction pathway and toxicity assessment.

    Science.gov (United States)

    Zheng, Qing; Dai, Yong; Han, Xiangyun

    2016-01-01

    In this study, ozonation treatment of C.I. Reactive Black 5 (RB5) was investigated at various operating parameters. The results showed that the aqueous solution initially containing 200 mg/L RB5 was quickly decolorized at pH 8.0 with an ozone dose of 3.2 g/h. Reaction intermediates with m/z 281, 546, 201, 350, 286 and 222 were elucidated using liquid chromatography-mass spectrometry, while sulfate ion, nitrate ion and three carboxylic acids (i.e., oxalic acid, formic acid, and acetic acid) were identified by ion exchange chromatography. Thus, the cleavage of the azo bond and the introduction of OH groups in the corresponding positions were proposed as the predominant reaction pathway. The detachment of sulfonic groups was also commonly observed during the ozonation treatment. The proposed degradation mechanism was confirmed by frontier electron density calculations, suggesting the feasibility of predicting the major events in the whole ozonation process with the computational method. Compared with RB5 degradation, the reduction of total organic carbon (TOC) proceeded much more slowly, and approximately 54% TOC was removed after 4 h of ozonation. Acute toxicity tests with Photobacterium phosphoreum showed that the toxicity of reaction solution was firstly increased and then decreased to a negligible level after 160 min.

  16. Degradation pathway, toxicity and kinetics of 2,4,6-trichlorophenol with different co-substrate by aerobic granules in SBR.

    Science.gov (United States)

    Khan, Mohammad Zain; Mondal, Pijush Kanti; Sabir, Suhail; Tare, Vinod

    2011-07-01

    The present study deals with cultivation of 2,4,6-trichlorophenol (TCP) degrading aerobic granules in two SBR systems based on glucose and acetate as co-substrate. Biodegradation of TCP containing wastewater starting from 10 to 360 mg L(-1) with more than 90% efficiency was achieved. Sludge volume index decreases as the operation proceeds to stabilize at 35 and 30 mL g(-1) while MLVSS increases from 4 to 6.5 and 6.2 g L(-1) for R1 (with glucose as co-substrate) and R2 (with sodium acetate as co-substrate), respectively. FTIR, GC and GC/MS spectral studies shows that the biodegradation occurred via chlorocatechol pathway and the cleavage may be at ortho-position. Haldane model for inhibitory substrate was applied to the system and it was observed that glucose fed granules have a high specific degradation rate and efficiency than acetate fed granules. Genotoxicity studies shows that effluent coming from SBRs was non-toxic. PMID:21565491

  17. Electroacupuncture inhibits apoptosis in annulus fibrosis cells through suppression of the mitochondria-dependent pathway in a rat model of cervical intervertebral disc degradation

    Directory of Open Access Journals (Sweden)

    Jun Liao

    2012-01-01

    Full Text Available The purpose of this study was to investigate whether treatment with electroacupuncture (EA inhibited mitochondria-dependent apoptosis in annulus fibrosis (AF cells in a rat model of cervical intervertebral disc degradation induced by unbalanced dynamic and static forces. Forty Sprague-Dawley rats were used in this study, of which 30 underwent surgery to induce cervical intervertebral disc degradation, 10 rats received EA at acupoints Dazhui (DU 14 and Shousanli (LI 10. TUNEL staining was measured to assess apoptosis in AF cells, immunohistochemistry was used to examine Bcl-2 and Bax expression, colorimetric assays were used to determine caspase 9 and caspase 3 activities and RT-PCR and western blotting were used to assess the mRNA and protein expression of Crk and ERK2. Treatment with EA reduced the number of AF-positive cells in TUNEL staining, increased Bcl-2-positive cells and decreased Bax-positive cells in immunohistochemical staining, significantly inhibited the activation of caspases-9 and -3, and enhanced the mRNA and protein expression of Crk and ERK2. Our data show that EA inhibits AF cell apoptosis via the mitochondria-dependent pathway and up-regulates Crk and ERK2 expression. These results suggest that treatment with may be a good alternative therapy for preventing cervical spondylosis.

  18. Decolorization of azo dye C.I. Reactive Black 5 by ozonation in aqueous solution: influencing factors, degradation products, reaction pathway and toxicity assessment.

    Science.gov (United States)

    Zheng, Qing; Dai, Yong; Han, Xiangyun

    2016-01-01

    In this study, ozonation treatment of C.I. Reactive Black 5 (RB5) was investigated at various operating parameters. The results showed that the aqueous solution initially containing 200 mg/L RB5 was quickly decolorized at pH 8.0 with an ozone dose of 3.2 g/h. Reaction intermediates with m/z 281, 546, 201, 350, 286 and 222 were elucidated using liquid chromatography-mass spectrometry, while sulfate ion, nitrate ion and three carboxylic acids (i.e., oxalic acid, formic acid, and acetic acid) were identified by ion exchange chromatography. Thus, the cleavage of the azo bond and the introduction of OH groups in the corresponding positions were proposed as the predominant reaction pathway. The detachment of sulfonic groups was also commonly observed during the ozonation treatment. The proposed degradation mechanism was confirmed by frontier electron density calculations, suggesting the feasibility of predicting the major events in the whole ozonation process with the computational method. Compared with RB5 degradation, the reduction of total organic carbon (TOC) proceeded much more slowly, and approximately 54% TOC was removed after 4 h of ozonation. Acute toxicity tests with Photobacterium phosphoreum showed that the toxicity of reaction solution was firstly increased and then decreased to a negligible level after 160 min. PMID:27054721

  19. Stimulatory effects of the degradation products from Mg-Ca-Sr alloy on the osteogenesis through regulating ERK signaling pathway

    Science.gov (United States)

    Li, Mei; He, Peng; Wu, Yuanhao; Zhang, Yu; Xia, Hong; Zheng, Yufeng; Han, Yong

    2016-09-01

    The influence of Mg-1Ca-xwt.% Sr (x = 0.2, 0.5, 1.0, 2.0) alloys on the osteogenic differentiation and mineralization of pre-osteoblast MC3T3-E1 were studied through typical differentiation markers, such as intracellular alkaline phosphatase (ALP) activity, extracellular collagen secretion and calcium nodule formation. It was shown that Mg-1Ca alloys with different content of Sr promoted cell viability and enhanced the differentiation and mineralization levels of osteoblasts, and Mg-1Ca-2.0Sr alloy had the most remarkable and significant effect among all. To further investigate the underlying mechanisms, RT-PCR and Western Blotting assays were taken to analyze the mRNA expression level of osteogenesis-related genes and intracellular signaling pathways involved in osteogenesis, respectively. RT-PCR results showed that Mg-1Ca-2.0Sr alloy significantly up-regulated the expressions of the transcription factors of Runt-related transcription factor 2 (RUNX2) and Osterix (OSX), Integrin subunits, as well as alkaline phosphatase (ALP), Bone sialoprotein (BSP), Collagen I (COL I), Osteocalcin (OCN) and Osteopontin (OPN). Western Blotting results suggested that Mg-1Ca-2.0Sr alloy rapidly induced extracellular signal-regulated kinase (ERK) activation but showed no obvious effects on c-Jun N terminal kinase (JNK) and p38 kinase of MAPK. Taken together, our results demonstrated that Mg-1Ca-2.0Sr alloy had excellent biocompatibility and osteogenesis via the ERK pathway and is expected to be promising as orthopedic implants and bone repair materials.

  20. Stimulatory effects of the degradation products from Mg-Ca-Sr alloy on the osteogenesis through regulating ERK signaling pathway

    Science.gov (United States)

    Li, Mei; He, Peng; Wu, Yuanhao; Zhang, Yu; Xia, Hong; Zheng, Yufeng; Han, Yong

    2016-01-01

    The influence of Mg-1Ca-xwt.% Sr (x = 0.2, 0.5, 1.0, 2.0) alloys on the osteogenic differentiation and mineralization of pre-osteoblast MC3T3-E1 were studied through typical differentiation markers, such as intracellular alkaline phosphatase (ALP) activity, extracellular collagen secretion and calcium nodule formation. It was shown that Mg-1Ca alloys with different content of Sr promoted cell viability and enhanced the differentiation and mineralization levels of osteoblasts, and Mg-1Ca-2.0Sr alloy had the most remarkable and significant effect among all. To further investigate the underlying mechanisms, RT-PCR and Western Blotting assays were taken to analyze the mRNA expression level of osteogenesis-related genes and intracellular signaling pathways involved in osteogenesis, respectively. RT-PCR results showed that Mg-1Ca-2.0Sr alloy significantly up-regulated the expressions of the transcription factors of Runt-related transcription factor 2 (RUNX2) and Osterix (OSX), Integrin subunits, as well as alkaline phosphatase (ALP), Bone sialoprotein (BSP), Collagen I (COL I), Osteocalcin (OCN) and Osteopontin (OPN). Western Blotting results suggested that Mg-1Ca-2.0Sr alloy rapidly induced extracellular signal-regulated kinase (ERK) activation but showed no obvious effects on c-Jun N terminal kinase (JNK) and p38 kinase of MAPK. Taken together, our results demonstrated that Mg-1Ca-2.0Sr alloy had excellent biocompatibility and osteogenesis via the ERK pathway and is expected to be promising as orthopedic implants and bone repair materials. PMID:27580744

  1. Species-specific diversity of novel bacterial lineages and differential abundance of predicted pathways for toxic compound degradation in scorpion gut microbiota.

    Science.gov (United States)

    Bolaños, Luis M; Rosenblueth, Mónica; Castillo-Ramírez, Santiago; Figuier-Huttin, Gilles; Martínez-Romero, Esperanza

    2016-05-01

    Scorpions are considered 'living fossils' that have conserved ancestral anatomical features and have adapted to numerous habitats. However, their gut microbiota diversity has not been studied. Here, we characterized the gut microbiota of two scorpion species, Vaejovis smithi and Centruroides limpidus. Our results indicate that scorpion gut microbiota is species-specific and that food deprivation reduces bacterial diversity. 16S rRNA gene phylogenetic analysis revealed novel bacterial lineages showing a low level of sequence identity to any known bacteria. Furthermore, these novel bacterial lineages were each restricted to a different scorpion species. Additionally, our results of the predicted metagenomic profiles revealed a core set of pathways that were highly abundant in both species, and mostly related to amino acid, carbohydrate, vitamin and cofactor metabolism. Notably, the food-deprived V. smithi shotgun metagenome matched almost completely the metabolic features of the prediction. Finally, comparisons among predicted metagenomic profiles showed that toxic compound degradation pathways were more abundant in recently captured C. limpidus scorpions. This study gives a first insight into the scorpion gut microbiota and provides a reference for future studies on the gut microbiota from other arachnid species. PMID:26058415

  2. Transport and degradation of dissolved organic matter and associated freshwater pathways in the Laptev Sea (Siberian Arctic)

    Science.gov (United States)

    Hoelemann, Jens; Janout, Markus; Koch, Boris; Bauch, Dorothea; Hellmann, Sebastian; Eulenburg, Antje; Heim, Birgit; Kassens, Heidemarie; Timokhov, leonid

    2016-04-01

    The Siberian shelves are seasonally ice-covered and characterized by large freshwater runoff rates from some of the largest rivers on earth. These rivers also provide a considerable amount of dissolved organic carbon (DOC) to the Arctic Ocean. With an annual load of about 6 Tg DOC a-1 the Lena River contributes nearly 20 percent of the annual DOC discharge to the Arctic Ocean. We present a comprehensive dataset collected during multiple Laptev Sea expeditions carried out in spring, summer and fall (2010-15) in order to explore the processes controlling the dispersal and degradation of DOM during the river water's passage across the shelf. Our investigations are focused on CDOM (Colored Dissolved Organic Matter), which resembles the DOC concentration, interacts with solar radiation and forms a major fraction of the organic matter pool. Our results show an inverse correlation between salinity and CDOM, which emphasizes its terrigenous source. Further, the spectral slope of CDOM absorption indicates that photochemical bleaching is the main process that reduces the CDOM absorption (~ 20%) in freshwater along its transport across the shelf. The distribution of the Lena river water is primarily controlled by winds in summer. During summers with easterly or southerly winds, the plume remains on the central and northern Laptev shelf, and is available for export into the Arctic Basin. The CDOM-rich river water increases the absorption of solar radiation and enhances warming of a shallow surface layer. This emphasizes the importance of CDOM for sea surface temperatures and lateral ice melt on the shelf and adjacent basin. DOC concentrations in freshwater vary seasonally and become larger with increasing discharge. Our data indicate that the CDOM concentrations are highest during the freshet when landfast ice is still present. Subsequent mixing with local sea ice meltwater lowers CDOM to values that are characteristic for the Lena freshwater during the rest of the year.

  3. OS9 Protein Interacts with Na-K-2Cl Co-transporter (NKCC2) and Targets Its Immature Form for the Endoplasmic Reticulum-associated Degradation Pathway.

    Science.gov (United States)

    Seaayfan, Elie; Defontaine, Nadia; Demaretz, Sylvie; Zaarour, Nancy; Laghmani, Kamel

    2016-02-26

    Mutations in the renal specific Na-K-2Cl co-transporter (NKCC2) lead to type I Bartter syndrome, a life-threatening kidney disease featuring arterial hypotension along with electrolyte abnormalities. We have previously shown that NKCC2 and its disease-causing mutants are subject to regulation by endoplasmic reticulum-associated degradation (ERAD). The aim of the present study was to identify the protein partners specifically involved in ERAD of NKCC2. To this end, we screened a kidney cDNA library through a yeast two-hybrid assay using NKCC2 C terminus as bait. We identified OS9 (amplified in osteosarcomas) as a novel and specific binding partner of NKCC2. Co-immunoprecipitation assays in renal cells revealed that OS9 association involves mainly the immature form of NKCC2. Accordingly, immunocytochemistry analysis showed that NKCC2 and OS9 co-localize at the endoplasmic reticulum. In cells overexpressing OS9, total cellular NKCC2 protein levels were markedly decreased, an effect blocked by the proteasome inhibitor MG132. Pulse-chase and cycloheximide-chase assays demonstrated that the marked reduction in the co-transporter protein levels was essentially due to increased protein degradation of the immature form of NKCC2. Conversely, knockdown of OS9 by small interfering RNA increased NKCC2 expression by increasing the co-transporter stability. Inactivation of the mannose 6-phosphate receptor homology domain of OS9 had no effect on its action on NKCC2. In contrast, mutations of NKCC2 N-glycosylation sites abolished the effects of OS9, indicating that OS9-induced protein degradation is N-glycan-dependent. In summary, our results demonstrate the presence of an OS9-mediated ERAD pathway in renal cells that degrades immature NKCC2 proteins. The identification and selective modulation of ERAD components specific to NKCC2 and its disease-causing mutants might provide novel therapeutic strategies for the treatment of type I Bartter syndrome.

  4. Copper-promoted circumneutral activation of H2O2 by magnetic CuFe2O4 spinel nanoparticles: Mechanism, stoichiometric efficiency, and pathway of degrading sulfanilamide.

    Science.gov (United States)

    Feng, Yong; Liao, Changzhong; Shih, Kaimin

    2016-07-01

    To evaluate the heterogeneous degradation of sulfanilamide by external energy-free Fenton-like reactions, magnetic CuFe2O4 spinel nanoparticles (NPs) were synthesized and used as catalysts for activation of hydrogen peroxide (H2O2). The physicochemical properties of the CuFe2O4 NPs were characterized with several techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and magnetometry. In the catalytic experiments, CuFe2O4 NPs/H2O2 oxidation showed the best degradation performance in the circumneutral conditions that resulted from the presence of Cu(II) on the surface of the CuFe2O4 NPs. The surface area-normalized pseudo-first-order rate constants were calculated as 2.60 × 10(-2) L m(-1) min(-1), 2.58 × 10(-3) L m(-1) min(-1), 1.92 × 10(-3) L m(-1) min(-1), and 7.30 × 10(-4) L m(-1) min(-1) for CuO, CuFe2O4 NPs, Fe3O4, and α-Fe2O3 catalysts, respectively. Thus, solid state Cu(II) was more reactive and efficient than Fe(III) in the circumneutral activation of H2O2; this finding was further supported by the results regarding the stoichiometric efficiency of H2O2. The effects of experimental parameters such as the oxidant dosage and catalyst loading were investigated. The mechanism for H2O2 activation on the spinel surface was explored and could be explained by the solid redox cycles of Fe(II)/Fe(III) and Cu(II)/Cu(I). Based on the products detected, a degradation pathway via the CS bond cleavage is proposed for the degradation of sulfanilamide. The findings of this study suggest that copper can be used as a doping metal to improve the reactivity and expand the effective pH range of iron oxides. PMID:27085318

  5. Chlorophyll catabolism in senescing plant tissues: In vivo breakdown intermediates suggest different degradative pathways for Citrus fruit and parsley leaves.

    Science.gov (United States)

    Amir-Shapira, D; Goldschmidt, E E; Altman, A

    1987-04-01

    High-pressure liquid chromatography was used to separate chlorophyll derivatives in acetone extracts from senescing Citrus fruit peel, autumnal Melia azedarach L. leaves, and dark-held detached parsley (Petroselinum sativum L.) leaves. Chlorophyllide a and another polar, dephytylated derivative accumulated in large amounts in senescing Citrus peel, particularly in fruit treated with ethylene. Ethylene also induced a 4-fold increase in the specific activity of Citrus chlorophyllase (chlorophyll chlorophyllidohydrolase, EC 3.1.1.14). Detailed kinetics based on a hexane/acetone solvent partition system showed that the in vivo increase in dephytylated derivatives coincided with the decrease in total chlorophyll. Polar, dephytylated derivatives accumulated also in senescing Melia leaves. Senescing parsley leaves revealed a very different picture. The gradual disappearance of chlorophyll a was accompanied by an increase in pheophytin a and by the transient appearance of several phytylated derivatives. Only pheophytin a and an adjacent peak were left when all the chlorophyll a had disappeared. The pathways for breakdown of chlorophyll in the Citrus and parsley senescence systems are discussed. PMID:16593821

  6. Diphenylarsinic acid contaminated soil remediation by titanium dioxide (P25) photocatalysis: Degradation pathway, optimization of operating parameters and effects of soil properties.

    Science.gov (United States)

    Wang, A-nan; Teng, Ying; Hu, Xue-feng; Wu, Long-hua; Huang, Yu-juan; Luo, Yong-ming; Christie, Peter

    2016-01-15

    Diphenylarsinic acid (DPAA) is formed during the leakage of arsenic chemical weapons in sites and poses a high risk to biota. However, remediation methods for DPAA contaminated soils are rare. Here, the photocatalytic oxidation (PCO) process by nano-sized titanium dioxide (TiO2) was applied to degrade DPAA in soil. The degradation pathway was firstly studied, and arsenate was identified as the final product. Then, an orthogonal array experimental design of L9(3)(4), only 9 experiments were needed, instead of 81 experiments in a conventional one-factor-at-a-time, was used to optimize the operational parameters soil:water ratio, TiO2 dosage, irradiation time and light intensity to increase DPAA removal efficiency. Soil:water ratio was found to have a more significant effect on DPAA removal efficiency than other properties. The optimum conditions to treat 4 g soil with a DPAA concentration of 20 mg kg(-1) were found to be a 1:10 soil: water ratio, 40 mW cm(-2) light intensity, 5% TiO2 in soil, and a 3-hour irradiation time, with a removal efficiency of up to 82.7%. Furthermore, this method (except for a change in irradiation time from 3 to 1.5h) was validated in nine different soils and the removal efficiencies ranged from 57.0 to 78.6%. Removal efficiencies were found to be negatively correlated with soil electrical conductivity, organic matter content, pH and total phosphorus content. Finally, coupled with electron spin resonance (ESR) measurement, these soil properties affected the generation of OH• by TiO2 in soil slurry. This study suggests that TiO2 photocatalytic oxidation is a promising treatment for removing DPAA from soil. PMID:26410709

  7. Reprogrammed Glucose Metabolic Pathways of Inhibitor-Tolerant Yeast

    Science.gov (United States)

    Representative inhibitory compounds such as furfural and 5-hydroxymethylfurfural generated from lignocellulosic biomass pretreatment inhibit yeast growth and interfere with the subsequent ethanol fermentation. Evolutionary engineering under laboratory settings is a powerful tool that can be used to ...

  8. Isolation of the phe-operon from G. stearothermophilus comprising the phenol degradative meta-pathway genes and a novel transcriptional regulator

    Directory of Open Access Journals (Sweden)

    Reiss Monika

    2008-11-01

    Full Text Available Abstract Background Geobacillus stearothermophilus is able to utilize phenol as a sole carbon source. A DNA fragment encoding a phenol hydroxylase catalyzing the first step in the meta-pathway has been isolated previously. Based on these findings a PCR-based DNA walk was performed initially to isolate a catechol 2,3-dioxygenase for biosensoric applications but was continued to elucidate the organisation of the genes encoding the proteins for the metabolization of phenol. Results A 20.2 kb DNA fragment was isolated as a result of the DNA walk. Fifteen open reading frames residing on a low-copy megaplasmid were identified. Eleven genes are co-transcribed in one polycistronic mRNA as shown by reverse transcription-PCR. Ten genes encode proteins, that are directly linked with the meta-cleavage pathway. The deduced amino acid sequences display similarities to a two-component phenol hydroxylase, a catechol 2,3-dioxygenase, a 4-oxalocrotonate tautomerase, a 2-oxopent-4-dienoate hydratase, a 4-oxalocrotonate decarboxylase, a 4-hydroxy-2-oxovalerate aldolase, an acetaldehyde dehydrogenase, a plant-type ferredoxin involved in the reactivation of extradiol dioxygenases and a novel regulatory protein. The only enzymes missing for the complete mineralization of phenol are a 2-hydroxymuconic acid-6-semialdehyde hydrolase and/or 2-hydroxymuconic acid-6-semialdehyde dehydrogenase. Conclusion Research on the bacterial degradation of aromatic compounds on a sub-cellular level has been more intensively studied in gram-negative organisms than in gram-positive bacteria. Especially regulatory mechanisms in gram-positive (thermophilic prokaryotes remain mostly unknown. We isolated the first complete sequence of an operon from a thermophilic bacterium encoding the meta-pathway genes and analyzed the genetic organization. Moreover, the first transcriptional regulator of the phenol metabolism in gram-positive bacteria was identified. This is a first step to elucidate

  9. UV/H2O2degradation of the antidepressants venlafaxine and O-desmethylvenlafaxine: Elucidation of their transformation pathway and environmental fate.

    Science.gov (United States)

    García-Galán, Ma Jesús; Anfruns, Alba; Gonzalez-Olmos, Rafael; Rodríguez-Mozaz, Sara; Comas, Joaquim

    2016-07-01

    The aim of the present work is to investigate the removal and transformation of the antidepressants venlafaxine (VFX) and its main metabolite O-desmethylvenlafaxine (DVFX) upon advanced oxidation with UV/H2O2 under lab conditions. High-resolution mass spectrometry (HRMS) analyses were carried out by means of ultra-high pressure liquid chromatography (UHPLC)-linear ion trap high resolution Orbitrap instrument (LTQ-Orbitrap-MS) in order to elucidate the different transformation products (TPs) generated. The depletion of both VFX and DVFX was very significant, with the 99.9% of both compounds eliminated after 5 and 30 min of reaction, respectively. Eleven TPs for VFX and six for DVFX were detected and their molecular structures elucidated by means of MS(2) and MS(3) scans, and the corresponding degradation pathways were proposed. The combined ecotoxicity at different treatment times was evaluated by means of bioluminescence inhibition assays with the marine bacteria Vibrio fischeri. Results showed an increase in the ecotoxicity during the UV/H2O2 experiment, especially at those reaction times where the total abundance of TPs was higher. PMID:26954478

  10. The Drosophila insulin-degrading enzyme restricts growth by modulating the PI3K pathway in a cell-autonomous manner.

    Science.gov (United States)

    Galagovsky, Diego; Katz, Maximiliano J; Acevedo, Julieta M; Sorianello, Eleonora; Glavic, Alvaro; Wappner, Pablo

    2014-03-01

    Mammalian insulin-degrading enzyme (IDE) cleaves insulin, among other peptidic substrates, but its function in insulin signaling is elusive. We use the Drosophila system to define the function of IDE in the regulation of growth and metabolism. We find that either loss or gain of function of Drosophila IDE (dIDE) can restrict growth in a cell-autonomous manner by affecting both cell size and cell number. dIDE can modulate Drosophila insulin-like peptide 2 levels, thereby restricting activation of the phosphatidylinositol-3-phosphate kinase pathway and promoting activation of Drosophila forkhead box, subgroup O transcription factor. Larvae reared in high sucrose exhibit delayed developmental timing due to insulin resistance. We find that dIDE loss of function exacerbates this phenotype and that mutants display increased levels of circulating sugar, along with augmented expression of a lipid biosynthesis marker. We propose that dIDE is a modulator of insulin signaling and that its loss of function favors insulin resistance, a hallmark of diabetes mellitus type II.

  11. Degradation of di(2-ethyl hexyl) phthalate by Fusarium culmorum: Kinetics, enzymatic activities and biodegradation pathway based on quantum chemical modelingpathway based on quantum chemical modeling.

    Science.gov (United States)

    Ahuactzin-Pérez, Miriam; Tlecuitl-Beristain, Saúl; García-Dávila, Jorge; González-Pérez, Manuel; Gutiérrez-Ruíz, María Concepción; Sánchez, Carmen

    2016-10-01

    Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in the manufacture of plastics, and it is an environmental contaminant. The specific growth rate (μ), maximum biomass (Xmax), biodegradation constant of DEHP (k), half-life (t1/2) of DEHP biodegradation and removal efficiency of DEHP, esterase and laccase specific activities, and enzymatic yield parameters were evaluated for Fusarium culmorum grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000mg/L). The greatest μ and the largest Xmax occurred in media supplemented with 1000mg of DEHP/L. F. culmorum degraded 95% of the highest amount of DEHP tested (1000mg/L) within 60h of growth. The k and t1/2 were 0.024h(-1) and 28h, respectively, for both DEHP concentrations. The removal efficiency of DEHP was 99.8% and 99.9% for 1000 and 500mg/L, respectively. Much higher specific esterase activity than specific laccase activity was observed in all media tested. The compounds of biodegradation of DEHP were identified by GC-MS. A DEHP biodegradation pathway by F. culmorum was proposed on the basis of the intermolecular flow of electrons of the identified intermediate compounds using quantum chemical modeling. DEHP was fully metabolized by F. culmorum with butanediol as the final product. This fungus offers great potential in bioremediation of environments polluted with DEHP.

  12. Disulfiram/copper-disulfiram Damages Multiple Protein Degradation and Turnover Pathways and Cytotoxicity is Enhanced by Metformin in Oesophageal Squamous Cell Carcinoma Cell Lines.

    Science.gov (United States)

    Jivan, Rupal; Damelin, Leonard Howard; Birkhead, Monica; Rousseau, Amanda Louise; Veale, Robin Bruce; Mavri-Damelin, Demetra

    2015-10-01

    Disulfiram (DSF), used since the 1950s in the treatment of alcoholism, is reductively activated to diethyldithiocarbamate and both compounds are thiol-reactive and readily complex copper. More recently DSF and copper-DSF (Cu-DSF) have been found to exhibit potent anticancer activity. We have previously shown that the anti-diabetic drug metformin is anti-proliferative and induces an intracellular reducing environment in oesophageal squamous cell carcinoma (OSCC) cell lines. Based on these observations, we investigated the effects of Cu-DSF and DSF, with and without metformin, in this present study. We found that Cu-DSF and DSF caused considerable cytotoxicity across a panel of OSCC cells, and metformin significantly enhanced the effects of DSF. Elevated copper transport contributes to DSF and metformin-DSF-induced cytotoxicity since the cell-impermeable copper chelator, bathocuproinedisulfonic acid, partially reversed the cytotoxic effects of these drugs, and interestingly, metformin-treated OSCC cells contained higher intracellular copper levels. Furthermore, DSF may target cancer cells preferentially due to their high dependence on protein degradation/turnover pathways, and we found that metformin further enhances the role of DSF as a proteasome inhibitor. We hypothesized that the lysosome could be an additional, novel, target of DSF. Indeed, this acid-labile compound decreased lysosomal acidification, and DSF-metformin co-treatment interfered with the progression of autophagy in these cells. In summary, this is the first such report identifying the lysosome as a target of DSF and based on the considerable cytotoxic effects of DSF either alone or in the presence of metformin, in vitro, and we propose these as novel potential chemotherapeutic approaches for OSCC.

  13. Characterization of the KstR-dependent promoter of the gene for the first step of the cholesterol degradative pathway in Mycobacterium smegmatis.

    Science.gov (United States)

    Uhía, Iria; Galán, Beatriz; Medrano, Francisco Javier; García, José Luis

    2011-09-01

    The KstR-dependent promoter of the MSMEG_5228 gene of Mycobacterium smegmatis, which encodes the 3-β-hydroxysteroid dehydrogenase (3-β HSD(MS)) responsible for the first step in the cholesterol degradative pathway, has been characterized. Primer extension analysis of the P₅₂₂₈ promoter showed that the transcription starts at the ATG codon, thus generating a leaderless mRNA lacking a 5' untranslated region (5'UTR). Footprint analyses demonstrated experimentally that KstR specifically binds to an operator region of 31 nt containing the quasi-palindromic sequence AACTGGAACGTGTTTCAGTT, located between the -5 and -35 positions with respect to the transcription start site. This region overlaps with the -10 and -35 boxes of the P₅₂₂₈ promoter, suggesting that KstR represses MSMEG_5228 transcription by preventing the binding of RNA polymerase. Using a P₅₂₂₈-β-galactosidase fusion we have demonstrated that KstR is able to work as a repressor in a heterologous system like Escherichia coli. A 3D model of the KstR protein revealed folding typical of TetR-type regulators, with two domains, i.e. a DNA-binding N-terminal domain and a regulator-binding C-terminal domain composed of six helices with a long tunnel-shaped hydrophobic pocket that might interact with a putative highly hydrophobic inducer. The finding that similar P₅₂₂₈ promoter regions have been found in all mycobacterial strains examined, with the sole exception of Mycobacterium tuberculosis, provides new clues about the role of cholesterol in the pathogenicity of this micro-organism. PMID:21565928

  14. Patchwork assembly of nag-like nitroarene dioxygenase genes and the 3-chlorocatechol degradation cluster for evolution of the 2-chloronitrobenzene catabolism pathway in Pseudomonas stutzeri ZWLR2-1.

    Science.gov (United States)

    Liu, Hong; Wang, Shu-Jun; Zhang, Jun-Jie; Dai, Hui; Tang, Huiru; Zhou, Ning-Yi

    2011-07-01

    Pseudomonas stutzeri ZWLR2-1 utilizes 2-chloronitrobenzene (2CNB) as a sole source of carbon, nitrogen, and energy. To identify genes involved in this pathway, a 16.2-kb DNA fragment containing putative 2CNB dioxygenase genes was cloned and sequenced. Of the products from the 19 open reading frames that resulted from this fragment, CnbAc and CnbAd exhibited striking identities to the respective α and β subunits of the Nag-like ring-hydroxylating dioxygenases involved in the metabolism of nitrotoluene, nitrobenzene, and naphthalene. The encoding genes were also flanked by two copies of insertion sequence IS6100. CnbAa and CnbAb are similar to the ferredoxin reductase and ferredoxin for anthranilate 1,2-dioxygenase from Burkholderia cepacia DBO1. Escherichia coli cells expressing cnbAaAbAcAd converted 2CNB to 3-chlorocatechol with concomitant nitrite release. Cell extracts of E. coli/pCNBC exhibited chlorocatechol 1,2-dioxygenase activity. The cnbCDEF gene cluster, homologous to a 3-chlorocatechol degradation cluster in Sphingomonas sp. strain TFD44, probably contains all of the genes necessary for the conversion of 3-chlorocatechol to 3-oxoadipate. The patchwork-like structure of this catabolic cluster suggests that the cnb cluster for 2CNB degradation evolved by recruiting two catabolic clusters encoding a nitroarene dioxygenase and a chlorocatechol degradation pathway. This provides another example to help elucidate the bacterial evolution of catabolic pathways in response to xenobiotic chemicals.

  15. DHA Inhibits Protein Degradation More Efficiently than EPA by Regulating the PPARγ/NFκB Pathway in C2C12 Myotubes

    OpenAIRE

    Yue Wang; Qiao-wei Lin; Pei-pei Zheng; Jian-song Zhang; Fei-ruo Huang

    2013-01-01

    This study was conducted to evaluate the mechanism by which n-3 PUFA regulated the protein degradation in C2C12 myotubes. Compared with the BSA control, EPA at concentrations from 400 to 600 µM decreased total protein degradation (P < 0.01). However, the total protein degradation was decreased when the concentrations of DHA ranged from 300 µM to 700 µM (P < 0.01). DHA (400 µM, 24 h) more efficiently decreased the I κ B α phosphorylation and increased in the I κ B α protein level than 400 µM E...

  16. 计算机重构石油烃降解的微生物代谢途径%Computational Reconstruction of Microbial Pathways for Degradation of Petroleum Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    王东; 何涛; 邵卫东; 汪莉; 王玉民

    2012-01-01

    目的:用计算机重构石油烃降解通路,为石油污染的生物修复提供理论依据.方法:利用KEGG反应、化合物数据提取反应等式,过滤掉所有反应中的通用化合物及小分子化合物并构建反应矩阵,然后利用广度优先搜索算法在反应矩阵中搜索降解石油烃的代谢途径.结果:计算机分别重构了256 132条链烷烃降解途径和44条环己烷降解途径,以酿酒酵母作为降解石油烃的基因工程菌为例,通过限制改构菌整合的关键酶数目,分别得到了213条不需要转入关键酶的链烷烃降解通路和6条以氧化还原酶、松柏醇脱氢酶或环己醇脱氢酶和环己酮单氧酶为关键酶的环己烷降解通路,并构建相应的降解网络图,标注每个反应的酶.结论:应用计算机重构了2种石油烃降解途径,可为利用微生物对石油污染进行生物修复提供理论依据.%Objective: Metabolic pathways for degradation of petroleum hydrocarbons were reconstructed by computational skills to provide theoretical basis for the bioremediation of oil polution. Methods: At first, the reaction equations were extracted from the KEGC reaction database and the compound database. And then current metabolites and micromolecule compounds in all the reactions were filtered out. Finally, the reaction matrix was constructed to search metabolic pathways for degrading petroleum hydrocarbons by the breadth first search approach. Results: 256 132 pathways for degrading alkanes and 44 pathways for degrading cyclohexane were reconstructed by computational skills. Taking Saccharomyces cerevisiae as the genetic engineering bacteria, we picked out 219 pathways by limiting the number of pivotal enzymes to construct the metabolic network, including 213 pathways without key enzymes and 6 pathways with oxidoreductases, coniferyl alcohol dehydrogenase or cyclohexanol dehydroge-nase and cyclohexanone monooxygenase as key enzymes. Catalytic enzymes of every reaction

  17. Evaluation of water matrix effects, experimental parameters, and the degradation pathway during the TiO2 photocatalytical treatment of the antibiotic dicloxacillin.

    Science.gov (United States)

    Villegas-Guzman, Paola; Silva-Agredo, Javier; González-Gómez, Duván; Giraldo-Aguirre, Ana L; Flórez-Acosta, Oscar; Torres-Palma, Ricardo A

    2015-01-01

    The photocalytic degradation of dicloxacillin (DXC) using TiO2 was studied in synthetic and natural waters. The degradation route and the effect of different experimental variables such as pH, applied power, and the initial concentrations of DXC and the catalyst were investigated. The best performances were achieved at a natural pH 5.8 and using 2.0 g L(-1) of TiO2 with 150 W of applied power. The photodegradation process followed Langmuir-Hinshelwood kinetics. The water matrix effect was evaluated in terms of degradation efficiency in the presence of organic compounds (oxalic acid, glucose), Fe(2+) ion and natural water. An increase in degradation was observed when ferrous ion was part of the solution, but the process was inhibited with all evaluated organic compounds. Similarly, inhibition was observed when natural water was used instead of distilled water. The extent of degradation of the process was evaluated following the evolution of chemical oxygen demand (COD), antimicrobial activity (AA), total organic carbon (TOC) and biochemical oxygen demand (BOD5). Total removal of DXC was achieved after 120 min of treatment and 95% mineralization was observed after 480 min of treatment. Additionally, the total removal of antimicrobial activity and a high level of biodegradability were observed after the photocalytical system had been operating for 240 min. PMID:25438130

  18. The role of the ubiquitination–proteasome pathway in breast cancer: Ubiquitin mediated degradation of growth factor receptors in the pathogenesis and treatment of cancer

    International Nuclear Information System (INIS)

    Aberrant activity of growth factor receptors has been implicated in the pathogenesis of a wide variety of malignancies. The negative regulation of signaling by growth factor receptors is mediated in large part by the ubiquitination, internalization, and degradation of the activated receptor. Over the past few years, considerable insight into the mechanisms that control receptor downregulation has been gained. There are also data suggesting that mutations that lead to inhibition of downregulation of growth factor receptors could play a role in the pathogenesis of cancer. Therapies directed at enhancing the degradation of growth factor receptors offer a promising approach to the treatment of malignancies

  19. Degradation of endogenous hepatic heme by pathways not yielding carbon monoxide. Studies in normal rat liver and in primary hepatocyte culture.

    OpenAIRE

    Bissell, D. M.; Guzelian, P S

    1980-01-01

    The conversion of endogenous hepatic heme to bilirubin and CO is established. However, it is unknown whether this process is quantitative or whether heme may be degraded to other products as well. To study this question, we administered the heme precursor, delta-amino-[5-14C]levulinic acid to rats in vivo. In liver, [14C]heme was predominately associated with microsomal cytochromes, and its degradation was examined over a period of 12--14 h; concurrently, excretion of labeled carbon monoxide ...

  20. Roles of horizontal gene transfer and gene integration in evolution of 1,3-dichloropropene- and 1,2-dibromoethane-degradative pathways

    NARCIS (Netherlands)

    Poelarends, GJ; Kulakov, LA; Larkin, MJ; Vlieg, JETV; Janssen, DB; Kulakov, Leonid A.; Larkin, Michael J.; Hylckama Vlieg, Johan E.T. van

    2000-01-01

    The haloalkane-degrading bacteria Rhodococcus rhodochrous NCIMB13064, Pseudomonas pavonaceae 170, and Mycobacterium sp. strain GP1 share a highly conserved haloalkane dehalogenase gene (dhaA). Here, we describe the extent of the conserved dhaA segments in these three phylogenetically distinct bacter

  1. Degradation of aromatic compounds through the beta-ketoadipate pathway is required for pathogenicity of the tomato wilt pathogen Fusarium oxysporum f. sp. lycopersici.

    NARCIS (Netherlands)

    C.B. Michielse; L. Reijnen; C. Olivain; C. Alabouvette; M. Rep

    2012-01-01

    Plant roots react to pathogen attack by the activation of general and systemic resistance, including the lignification of cell walls and increased release of phenolic compounds in root exudate. Some fungi have the capacity to degrade lignin using ligninolytic extracellular peroxidases and laccases.

  2. The role of the ubiquitination–proteasome pathway in breast cancer: Ubiquitin mediated degradation of growth factor receptors in the pathogenesis and treatment of cancer

    OpenAIRE

    Lipkowitz, Stan

    2002-01-01

    Aberrant activity of growth factor receptors has been implicated in the pathogenesis of a wide variety of malignancies. The negative regulation of signaling by growth factor receptors is mediated in large part by the ubiquitination, internalization, and degradation of the activated receptor. Over the past few years, considerable insight into the mechanisms that control receptor downregulation has been gained. There are also data suggesting that mutations that lead to inhibition of downregulat...

  3. Exogenous Melatonin Suppresses Dark-Induced Leaf Senescence by Activating the Superoxide Dismutase-Catalase Antioxidant Pathway and Down-Regulating Chlorophyll Degradation in Excised Leaves of Perennial Ryegrass (Lolium perenne L.)

    Science.gov (United States)

    Zhang, Jing; Li, Huibin; Xu, Bin; Li, Jing; Huang, Bingru

    2016-01-01

    Leaf senescence is a typical symptom in plants exposed to dark and may be regulated by plant growth regulators. The objective of this study was to determine whether exogenous application of melatonin (N-acetyl-5-methoxytryptamine) suppresses dark-induced leaf senescence and the effects of melatonin on reactive oxygen species (ROS) scavenging system and chlorophyll degradation pathway in perennial grass species. Mature perennial ryegrass (Lolium perenne L. cv. ‘Pinnacle’) leaves were excised and incubated in 3 mM 2-(N-morpholino) ethanesulfonic buffer (pH 5.8) supplemented with melatonin or water (control) and exposed to dark treatment for 8 days. Leaves treated with melatonin maintained significantly higher endogenous melatonin level, chlorophyll content, photochemical efficiency, and cell membrane stability expressed by lower electrolyte leakage and malondialdehyde (MDA) content compared to the control. Exogenous melatonin treatment also reduced the transcript level of chlorophyll degradation-associated genes and senescence marker genes (LpSAG12.1, Lph36, and Lpl69) during the dark treatment. The endogenous O2- production rate and H2O2 content were significantly lower in these excised leaves treated with melatonin compared to the water control. Exogenous melatonin treatment caused increases in enzymatic activity and transcript levels of superoxide dismutase and catalase but had no significant effects on ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase. The content of non-enzymatic antioxidants, such as ascorbate and dehydroascorbate, were decreased by melatonin treatment, while the content of glutathione and oxidized glutathione was not affected by melatonin. These results suggest that the suppression of dark-induced leaf senescence by exogenous melatonin may be associated with its roles in regulating ROS scavenging through activating the superoxide dismutase-catalase enzymatic antioxidant pathway and

  4. HIV-1 Nef targets MHC-I and CD4 for degradation via a final common beta-COP-dependent pathway in T cells.

    Directory of Open Access Journals (Sweden)

    Malinda R Schaefer

    Full Text Available To facilitate viral infection and spread, HIV-1 Nef disrupts the surface expression of the viral receptor (CD4 and molecules capable of presenting HIV antigens to the immune system (MHC-I. To accomplish this, Nef binds to the cytoplasmic tails of both molecules and then, by mechanisms that are not well understood, disrupts the trafficking of each molecule in different ways. Specifically, Nef promotes CD4 internalization after it has been transported to the cell surface, whereas Nef uses the clathrin adaptor, AP-1, to disrupt normal transport of MHC-I from the TGN to the cell surface. Despite these differences in initial intracellular trafficking, we demonstrate that MHC-I and CD4 are ultimately found in the same Rab7(+ vesicles and are both targeted for degradation via the activity of the Nef-interacting protein, beta-COP. Moreover, we demonstrate that Nef contains two separable beta-COP binding sites. One site, an arginine (RXR motif in the N-terminal alpha helical domain of Nef, is necessary for maximal MHC-I degradation. The second site, composed of a di-acidic motif located in the C-terminal loop domain of Nef, is needed for efficient CD4 degradation. The requirement for redundant motifs with distinct roles supports a model in which Nef exists in multiple conformational states that allow access to different motifs, depending upon which cellular target is bound by Nef.

  5. Deficiency of ATP2C1, a golgi ion pump, induces secretory pathway defects in endoplasmic reticulum ( ER)-associated degradation and sensitivity to ER stress

    NARCIS (Netherlands)

    Ramos-Castaneda, J; Park, YN; Liu, M; Hauser, K; Rudolph, H; Shull, GE; Jonkman, MF; Mori, K; Ikeda, S; Ogawa, H; Arvan, P

    2005-01-01

    Relatively few clues have been uncovered to elucidate the cell biological role(s) of mammalian ATP2C1 encoding an inwardly directed secretory pathway Ca2+/Mn2+ pump that is ubiquitously expressed. Deficiency of ATP2C1 results in a human disease ( Hailey-Hailey), which primarily affects keratinocytes

  6. Chemotaxis to furan compounds by furan-degrading Pseudomonas strains

    Science.gov (United States)

    Two Pseudomonas strains known to utilize furan derivatives were shown to be attracted to furfural, 5-hydroxymethylfurfural, furfuryl alcohol, and 2-furoic acid in the absence of furan metabolism. In addition, a LysR-family regulatory protein known to regulate furan metabolic genes was found to be i...

  7. TOF-SIMS investigation of degradation pathways occurring in a variety of organic photovoltaic devices – the ISOS-3 inter-laboratory collaboration

    DEFF Research Database (Denmark)

    Andreasen, Birgitta; Tanenbaum, David; Hermenau, Martin;

    2012-01-01

    The present work is the fourth (and final) contribution to an inter-laboratory collaboration that was planned at the 3rd International Summit on Organic Photovoltaic Stability (ISOS-3). The collaboration involved six laboratories capable of producing seven distinct sets of OPV devices that were......-depth in the organic solar cells. Various degradation mechanisms were investigated and correlated with cell performance. For example, photo-oxidation of the active material was quantitatively studied as a function of cell performance. The large variety of cell architectures used (some with and some without...... of organic solar cells....

  8. Epidermal Growth Factor Cytoplasmic Domain Affects ErbB Protein Degradation by the Lysosomal and Ubiquitin-Proteasome Pathway in Human Cancer Cells

    Directory of Open Access Journals (Sweden)

    Aleksandra Glogowska

    2012-05-01

    Full Text Available The cytoplasmic domains of EGF-like ligands, including EGF cytoplasmic domain (EGFcyt, have important biological functions. Using specific constructs and peptides of human EGF cytoplasmic domain, we demonstrate that EGFcyt facilitates lysosomal and proteasomal protein degradation, and this coincided with growth inhibition of human thyroid and glioma carcinoma cells. EGFcyt and exon 22–23-encoded peptide (EGF22.23 enhanced procathepsin B (procathB expression and procathB-mediated lysosomal degradation of EGFR/ErbB1 as determined by inhibitors for procathB and the lysosomal ATPase inhibitor BafA1. Presence of mbEGFctF, EGFcyt, EGF22.23, and exon 23-encoded peptides suppressed the expression of the deubiqitinating enzyme ubiquitin C-terminal hydrolase-L1 (UCH-L1. This coincided with hyperubiquitination of total cellular proteins and ErbB1/2 and reduced proteasome activity. Upon small interfering RNA-mediated silencing of endogenously expressed UCH-L1, a similar hyperubiquitinylation phenotype, reduced ErbB1/2 content, and attenuated growth was observed. The exon 23-encoded peptide region of EGFcyt was important for these biologic actions. Structural homology modeling of human EGFcyt showed that this molecular region formed an exposed surface loop. Peptides derived from this EGFcyt loop structure may aid in the design of novel peptide therapeutics aimed at inhibiting growth of cancer cells.

  9. Analysis of the Durability of PEM FC Membrane Electrode Assemblies in Automotive Applications through the Fundamental Understanding of Membrane and MEA Degradation Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Randal L. [DuPont

    2013-10-31

    The Project focused on mitigation of degradation processes on membrane electrode assemblies. The approach was to develop a model to improve understanding of the mechanisms, and to use it to focus mitigation strategies. The detailed effects of various accelerated stress tests (ASTs) were evaluated to determine the best subset to use in model development. A combination of ASTs developed by the Fuel Cell Commercialization Conference of Japan and the Fuel Cell Tech Team were selected for use. The ASTs were compared by measuring effects on performance, running in-situ diagnostics, and performing microscopic analyses of the membrane electrode assemblies after the stress tests were complete. Nissan ran FCCJ AST protocols and performed in situ and ex-situ electrochemical testing. DuPont ran FCTT and USFCC AST protocols, performed scanning and transmission electron microscopy and ran in-situ electrochemical tests. Other ex-situ testing was performed by IIT, along with much of the data analysis and model development. These tests were then modified to generate time-dependent data of the degradation mechanisms. Three different catalyst types and four membrane variants were then used to generate data for a theoretically-based degradation model. An important part of the approach was to use commercially available materials in the electrodes and membranes made in scalable semiworks processes rather than lab-based materials. This constraint ensured all materials would be practicable for full-scale testing. The initial model for the electrode layer was tested for internal consistency and agreement with the data. A Java-based computer application was developed to analyze the time-dependent AST data using polarization curves with four different cathode gas feeds and generate model parameters. Data showed very good reproducibility and good consistency as cathode catalyst loadings were varied. At the point of termination of the project, a basic electrode model was in hand with several

  10. Construction of Hemoglobin Degradation Pathway of Schistosoma and Analysis of Conserved Domains of Pathway Key Enzymes%血吸虫血红蛋白降解途径的重构及关键酶蛋白保守结构域的分析

    Institute of Scientific and Technical Information of China (English)

    魏佳; 李园园; 李亦学; 于复东

    2011-01-01

    On the basis of hemoglobin degradation pathway of Plasmodium falciparum, hemoglobin degradation pathways of Schistosoma japonicum and Schistosoma mansoni were constructed using bioinformatic methods. Sequences and structures of conserved domains of pathway key enzymes were analyzed after pathway construction. The catalytic sites of predicted hemoglobinases of Schistosoma are highly conserved with Plasmodium in both sequence and structure level. This paper provides a theoretical foundation for Schistosoma hemoglobinase study, and analysis of their interactions with substrates or inhibitors in three-dimensional level.%利用生物信息学方法,以疟原虫的血红蛋白降解途径为基础,成功地构建出了日本血吸虫和曼氏血吸虫的血红蛋白降解途径,并对降解途径上的关键酶蛋白的保守结构域进行了序列及结构分析。预测得到的血吸虫血红蛋白降解酶保守结构域,与疟原虫相比,在序列上催化位点高度保守,在结构上空间相对位置较一致,为研究血吸虫血红蛋白降解酶,及其与底物或抑制剂在三维结构上的相互作用提供了理论基础。

  11. Targeting a novel bone degradation pathway in primary bone cancer by inactivation of the collagen receptor uPARAP/Endo180

    DEFF Research Database (Denmark)

    Engelholm, Lars H; Melander, Maria C; Hald, Andreas;

    2016-01-01

    In osteosarcoma, a primary mesenchymal bone cancer occurring predominantly in younger patients, invasive tumour growth leads to extensive bone destruction. This process is insufficiently understood, cannot be efficiently counteracted and calls for novel means of treatment. The endocytic collagen...... of degrading the protein component of surface-labelled bone slices in a process dependent on MMP activity and uPARAP/Endo180. Systemic treatment of the sarcoma-inoculated mice with a mouse monoclonal antibody that blocks murine uPARAP/Endo180 led to a strong reduction of bone destruction. Our findings identify...... receptor, uPARAP/Endo180, is expressed on various mesenchymal cell types and is involved in bone matrix turnover during normal bone growth. Human osteosarcoma specimens showed strong expression of this receptor on tumour cells, along with the collagenolytic metalloprotease, MT1-MMP. In advanced tumours...

  12. Rhodococcus sp.BX2菌对乙腈的降解特性及降解途径研究%Characteristics and pathway of acetonitrile degradation by Rhodococcus sp.BX2

    Institute of Scientific and Technical Information of China (English)

    孙晶; 熊明华; 成小松; 李悦; 臧海莲; 李春艳

    2012-01-01

    对Rhodococcus sp.BX2菌降解乙腈的特性及其降解途径进行了研究.结果显示,在底物浓度为800mg·L-1,接种量为1.0%,培养温度为35℃,环境pH为7.5的条件下,16h时Rhodococcus sp.BX2菌对乙腈的降解率为95.98%;添加葡萄糖可在培养初期加快Rhodococcus sp.BX2菌的生长和对乙腈的降解,蔗糖、乙酰胺和尿素对其影响不大.将BX2菌接种到含有高乙腈浓度(25000mg·L-1)的合成废水中,培养180h后,乙腈降解率可达88.59%.在催化反应60min后,Rhodococcus sp.BX2腈水合酶与腈水解酶的总酶活可达到422.81U·mL-1,对其相关基因序列的分析结果表明,Rhodococcus sp.BX2中同时存在腈水解酶基因和腈水合酶基因,因此,确定乙腈的降解主要由腈水合酶途径完成,可能同时存在腈水解酶的降解途径.%The characteristics and pathway of acetonitrile degradation by Rhodococcus sp.BX2 were investigated in this study. Results showed that with the initial acetonitrile concentration of 800 mg · L-1, the degradation rate was 95.98% in 16 hours under the condition of inoculum 1.0%, 35 ℃ and pH value 7.5.Glucose could accelerate the degradation of acetonitrile in the initial period, while sucrose, acetamide and urea had slight impact. The degradation rate could reach 88.59% when BX2 was cultured in the synthetic wastewater with high concentration of acetonitrile (25000 mg · L-1) for 180 hours. Total enzyme activities was 422.81 U · mL-1 when incubated for 60 minutes. The results of related genes sequence showed that Rhodococcus sp BX2 had both nitrile hydrolase gene and nitrile hydratase gene. The degradation pathway of acetonitrile by Rhodococcus sp. BX2 was mainly nitrile hydratase (NHase), with possible pathway of the nitrile hydrolase.

  13. 一株喹啉降解菌的降解特性及代谢途径研究%BIODEGRADATION CHARACTERISTICS AND METABOLIC PATHWAY OF A STRAIN FOR QUINOLINE DEGRADATION

    Institute of Scientific and Technical Information of China (English)

    庹保华; 刘学东; 王广鹏; 颜家保

    2012-01-01

    A bacterial strain (Q2) , which could utilize quinoline as the sole sources of carbon, nitrogen and energy, was isolated from the soil contaminated by petroleum at the wastewater treating plant of a petrochemical refinery. Biodegradation experiments showed that this strain could degrade 500 mg/L of quinoline in growth medium completely within 32 h. The optimum degradation temperature, initial pH of growth medium and rotary speed of shaker for Q2 utilizing quinoline was 30℃, pH 8—10 and 100—200 r/min, respectively. The initial concentration of quinoline had great impact on the degradation by Q2, and this degradation process agreed with zero order kinetics equation when the initial concentration of quinoline in the range of 195—796 mg/L. During the biodegradation, the color of the medium changed from yellow to pink, and brown finally. FT-IR analysis exhibited that the degradation of quinoline was probably followed 8-hydroxycoumarin metabolic pathway, and that the nitrogen atom of hetero-cyclic compound was released as ammonium into the growth medium.%从某石化厂污水处理站厂区内受石油污染的土壤中分离出1株能以喹啉为唯一碳源、氮源和能源生长代谢的菌株Q2.降解试验结果表明,Q2能将喹啉质量浓度为500 mg/L的培养液中的喹啉在32 h内完全去除,其降解喹啉的适宜温度为30℃、培养基初始pH值为8~10、摇床转速为100~200 r/min;喹啉浓度对Q2的降解有较大影响,喹咻质量浓度为195~796 mg/L时,Q2降解喹啉的过程符合零级动力学方程.生物降解过程中,培养液从黄色变为粉红色,最后呈棕色.红外光谱分析显示,Q2降解途径很可能为8-羟基香豆素途径,且杂环上氮原子以氨氮的形式释放.

  14. 河道底泥中四溴双酚A厌氧降解及代谢途径%Anaerobic degradation and pathways of tetrabromobisphenol A in river sediments

    Institute of Scientific and Technical Information of China (English)

    李玲玲; 刘世诚; 朱崇岭; 任源; 岑锦涛

    2014-01-01

    采用血清瓶实验研究了3种河道底泥(新造、清远和贵屿镇)中四溴双酚A( TBBPA)厌氧降解特性,结果表明,不同河道底泥TBBPA降解速率有差异,作为垃圾拆解地的贵屿河道底泥降解速率最快,添加电子供体能加快TBBPA的降解.TBBPA厌氧降解符合拟一级动力学,50μmol·L-1 TBBPA降解速率为0.0491 d-1,对应半衰期为16.0 d;降解速率与TBBPA初始浓度成反比,高浓度下抑制微生物活动,从而影响TBBPA降解速率.采用UPLC-MS/MS分析TBBPA降解中间产物,发现与3,3′,5-三溴双酚A( tri-BBPA)、3-溴双酚A( mono-BBPA)以及双酚A( BPA)对应的特征质子图谱,从而推测TBBPA在厌氧条件下的转化途径为经由三溴双酚A、一溴双酚A、生成双酚A.%Tetrabromobisphenol A ( TBBPA) is a kind of widely used brominated flame retardants throughout the world and presented in the environment ubiquitously. This study investigated the anaerobic degradation of TBBPA in three river sediments ( Xinzao, Qingyuan, and Guiyu Town in Guangdong Province) by conducting serum bottle experiments. The results showed that the three sediments had different degradation capabilities, and the sediment in Guiyu Town, an E-waste dismantling site, had the highest TBBPA anaerobic degradation rate. Moreover, The addition of electron donors can enhance the debromination of TBBPA. The half-lives (t1/2) of TBBPA anaerobic degradation in the sediments were 16. 0 d,39. 7 d, and 84. 1 d at concentrations of 50, 100, and 200 μmol·L-1, respectively. High concentration TBBPA inhibited debromination process. Furthermore, 3,3′,5-tribromobisphenol A ( tri-BBPA) , 3-monobromobisphenol A ( mono-BBPA) , and bisphenol A ( BPA) were detected through UPLC-MS/MS method. The following pathway of TBBPA degradation in anaerobic sediments was proposed:TBBPA-tri-BBPA-mono-BBPA-BPA.

  15. Rho iso-alpha acids from hops inhibit the GSK-3/NF-κB pathway and reduce inflammatory markers associated with bone and cartilage degradation

    Directory of Open Access Journals (Sweden)

    Bland Jeffrey S

    2009-08-01

    Full Text Available Abstract Background Rho iso-alpha acids (RIAA from hops have been shown to have anti-inflammatory properties. To understand the mechanisms, we evaluated the effect of RIAA in cell signaling pathways and inflammatory markers using various in vitro models. We also investigated their therapeutic effect in mice with collagen-induced arthritis. Methods The LPS-stimulated RAW 264.7 macrophages were used to evaluate the effect of RIAA on the NF-κB and MAPK signaling pathways; phosphorylation of ERK1/2, p38 and JNK was assessed by western blotting and NF-κB binding by electrophoretic mobility shift assays. Effect on the NF-κB activity was evaluated by the luciferase reporter assays in LPS-stimulated RAW 264.7 cells. GSK-3α/β kinase activity was measured in cell-free assays. The inhibitory effect of RIAA on inflammatory markers was assessed by measuring nitric oxide in LPS-stimulated RAW 264.7 cells, RANKL-mediated TRAP activity in transformed osteoclasts, and TNF-α/IL-1β-mediated MMP-13 expression in SW1353 cells. Mice with collagen-induced arthritis were fed with RIAA for 2 weeks. Symptoms of joint swelling, arthritic index and joint damage were assessed. Results RIAA selectively inhibited the NF-κB pathway while having no effect on ERK1/2, p38 and JNK phosphorylation in LPS-stimulated RAW 264.7 cells. RIAA also inhibited GSK-3α/β kinase activity and GSK-3β dependent phosphorylation of β-catenin in RAW 264.7 cells. In addition, RIAA inhibited NF-κB-mediated inflammatory markers in various cell models, including nitric oxide in LPS-stimulated RAW 264.7 cells, RANKL-mediated TRAP activity in transformed osteoclasts, and TNF-α/IL-1β-mediated MMP-13 expression in SW1353 human chondrosarcoma cells. Finally, in a mouse model of collagen-induced arthritis, RIAA ameliorated joint damage as evidenced by significant reduction of the arthritis index and histology score; at 250 mg/kg-body weight, RIAA had efficacy similar to that of 20 mg

  16. TRANSFORMING GROWTH FACTOR-β1 AND SMAD4 SIGNALING PATHWAY DOWN-REGULATES RENAL EXTRACELLULAR MATRIX DEGRADATION IN DIABETIC RATS

    Institute of Scientific and Technical Information of China (English)

    Qin Yang; Ru-jia Xie; Ting Yang; Li Fang; Bing Han; Guo-zhong Zhang; Ming-liang Cheng

    2007-01-01

    To investigate the role of transforming growth factor-β1 ( TGF-β1 )/Smad4 pathway in development of renal fibrosis in streptozotocin (STZ)-induced diabetic nephropathy (DN) rats and explore its possible mechanism.Methods Male Wistar rats weighing 180-220 g were divided into 5 groups: group A ( normal control), group B[ diabetes mellitus (DM) 2 weeks], group C (DM4 weeks), group D (DM 8 weeks), and group E (DM 16 weeks).Except for the normal control group, other groups were induced DM by single injection of STZ (55 mg/kg) respectively. Blood glucose level, serum creatinine, and 24-hour urine protein were examined. Expressions of TGF-β1 and Smad4 protein and mRNA in kidney were detected using immunohistochemical technique, Western blot, and real-time PCR. mRNA expressions of stromelysin-1 ( MMP-3 ), tissue inhibitor of metalloproteinase-1 ( TIMP-1 ), and collagen Ⅲ in kidney were also detected by real-time PCR..Results The levels of blood glucose, serum creatinine, and 24-hour urine protein in rats of group B, C, D, and E were higher than those of the control group. With the progression of renal fibrosis, the expressions of TGF-β1 and Smad4 protein and mRNA in kidney of diabetic rats elevated. In addition, the renal MMP-3 mRNA expression diminished in diabetic rats, while TIMP-1 and collagen Ⅲ mRNA increased.Conclusions In STZ-induced diabetic rats, the TGF-β1/Smad4 appears to play an important role in renal fibrosis of DN. The increased expression of TGF-β1 and Smad4 might result in the transcriptional regulation of downstream target genes of TGF-β1/Smad4 pathway, which contributes to the progression of renal fibrosis in diabetic rats.

  17. Congenital cataract causing mutants of αA-crystallin/sHSP form aggregates and aggresomes degraded through ubiquitin-proteasome pathway.

    Directory of Open Access Journals (Sweden)

    Ilangovan Raju

    Full Text Available BACKGROUND: Mutations of human αA-crystallin cause congenital cataract by protein aggregation. How mutations of αA-crystallin cause disease pathogenesis through protein aggregation is not well understood. To better understand the cellular events leading to protein aggregation, we transfected cataract causing mutants, R12C, R21L, R21W, R49C, R54C, R116C and R116H, of human αA-crystallin in HeLa cells and examined the formation of intracellular protein aggregates and aggresomes by confocal microscopy. METHODOLOGY/PRINCIPAL FINDINGS: YFP-tagged human αA-wild-type (αA-wt was sub-cloned and the mutants were generated by site-directed mutagenesis. The αA-wt and the mutants were individually transfected or co-transfected with CFP-tagged αA-wt or αB-wild-type (αB-wt in HeLa cells. Overexpression of these mutants forms multiple small dispersed cytoplasmic aggregates as well as aggresomes. Co-expression of αB-wt with these mutants significantly inhibited protein aggregates where as co-expression with αA-wt enhanced protein aggregates which seems to be due to co-aggregation of the mutants with αA-wt. Aggresomes were validated by double immunofluorescence by co-localization of γ-tubulin, a centrosome marker protein with αA-crystallin. Furthermore, increased ubiquitination was detected in R21W, R116C and R116H as assessed by western blot analyses. Immunostaining with an ubiquitin antibody revealed that ubiquitin inclusions in the perinuclear regions were evident only in R116C transfected cells. Pulse chase assay, after cycloheximide treatment, suggested that R116C degraded faster than the wild-type control. CONCLUSIONS/SIGNIFICANCE: Mutants of αA-crystallin form aggregates and aggresomes. Co-expression of αA-wt with the mutants increased aggregates and co-expression of αB-wt with the mutants significantly decreased the aggregates. The mutant, R116C protein degraded faster than wild-type control and increased ubiquitination was evident in R

  18. Isolation,identification,degradation characteristics and pathway of a pyrethroid-degrading bacterial strain%一株拟除虫菊酯农药降解菌的分离鉴定及其降解特性与途径

    Institute of Scientific and Technical Information of China (English)

    陈少华; 罗建军; 胡美英; 赖开平; 耿鹏; 肖盈

    2011-01-01

    A bacterial strain named P-01 was newly isolated by enrichment culture from the activated sludge in the wastewater of a pyrethroid-manufacturer in Zhongshan.Based on the morphology,physio-biochemical characteristics,and 16S rDNA sequence analysis,strain P-01 was temporarily identified as Achromobacter sp.P-01.Response surface methodology(RSM) was used to optimize degradation conditions.The optimal conditions for biodegradation were obtained as follows:31.4℃,pH 7.6 and inoculum biomass 0.4 g · L-1.Under the optimal degradation conditions,strain P-01 could effectively degrade deltamethrin,fenvalerate,beta-cypermethrin,beta-cyfluthrin and cyhalothrin with degradation rates of 98.9%,92.2%,91.0%,85.1% and 77.3%,respectively,within 7 days of incubation.Strain P-01 not only could utilize deltamethrin as the sole carbon source and energy for growth in mineral salt medium(MSM),but also could tolerate and efficiently degrade high concentrations of deltamethrin(100~500 mg · L-1).Furthermore,the degradation reaction followed first-order kinetics and half lives(T1/2) were 1.3,1.8,2.0,2.5 and 3.0 d,respectively.Studies on the degradation pathway showed that deltamethrin was degraded by hydrolysis of the carboxylester linkage to yield alpha-hydroxy-3-phenoxy-benzeneacetonitrile and 3-phenoxy benzaldehyde,and then the intermediates were further degraded by oxygenolysis to form 2-hydroxy-4-methoxy benzophenone and 1,2-benzenedicarboxylic acid,mono ester,finally resulting in complete detoxification.%采用富集培养法,从拟除虫菊酯农药厂废水排放口的活性污泥中分离到1株菊酯农药高效降解菌P-01.经形态、生理生化特征及16S rDNA序列分析,初步鉴定其为无色杆菌属(Achromobacter sp.).响应曲面法优化菌株P-01的降解条件,其降解最优条件为31.4℃、初始pH7.6和接种量0.4g·L-1,在此条件下,该菌株培养7d对50mg·L-1溴氰菊酯、氰戊菊酯、高效氯氰菊酯、高效氟

  19. An optimized capillary electrophoresis method for the simultaneous analysis of biomass degradation products in ionic liquid containing samples.

    Science.gov (United States)

    Aid, Tiina; Paist, Loore; Lopp, Margus; Kaljurand, Mihkel; Vaher, Merike

    2016-05-20

    An indirect capillary electrophoresis method for a quantitative determination of mono-, di- and oligosaccharides was developed to investigate biomass degradation, the isomerization of glucose into fructose and conversion of fructose to 5-hydroxymethylfurfural (5-HMF) in ionic liquids (ILs). Three chromophores, namely 2,6-pyridinedicarboxylic acid (PDC), maleic acid and phthalic acid, were used to perform indirect detection. The electroosmotic flow (EOF) was reversed to reduce analysis time, using 1-tetradecyl-3-methylimidazolium chloride (C14MImCl). The simultaneous separation of the underivatized mono-, di- and oligosaccharides was performed using four cellodextrin oligomers (cellotriose, cellotetraose, cellopentaose, cellohexaose), eight carbohydrates (xylose, fructose, glucose, galactose, lactose, cellobiose, raffinose, sucrose), two organic acids (acetic acid, levulinic acid) and 5-HMF. The best performance was obtained using background electrolyte (BGE) composed of 138.2mM NaOH, 40mM maleic acid and 5mMC14MImCl, the applied voltage was -21.7kV. The linear ranges for analyzed compounds were following: organic acids, raffinose and sucrose from 0.20 to 7mM, cellodextrin oligomers from 0.25 to 5mM, other analyzed carbohydrates from 0.25 to 7mM and 5-HMF from 0.05 to 7mM. The relative standard deviations (RSD) of peak areas varied from 3.47 to 9.62% during a 5-day analysis period and 0.58-5.29% during one day. PMID:27095128

  20. Microbial Degradation of Indole and Its Derivatives

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-01-01

    Full Text Available Indole and its derivatives, including 3-methylindole and 4-chloroindole, are environmental pollutants that are present worldwide. Microbial degradation of indole and its derivatives can occur in several aerobic and anaerobic pathways; these pathways involve different known and characterized genes. In this minireview, we summarize and explain the microbial degradation of indole, indole-3-acetic acid, 4-chloroindole, and methylindole.

  1. Rationally rewiring the connectivity of the XylR/Pu regulatory node of the m-xylene degradation pathway in Pseudomonas putida.

    Science.gov (United States)

    de Las Heras, Aitor; Martínez-García, Esteban; Domingo-Sananes, Maria Rosa; Fraile, Sofia; de Lorenzo, Víctor

    2016-04-18

    The XylR/Pu regulatory node of the m-xylene biodegradation pathway of Pseudomonas putida mt-2 is one of the most intricate cases of processing internal and external cues into a single controlling element. Despite this complexity, the performance of the regulatory system is determined in vivo only by the occupation of Pu by m-xylene-activated XylR and σ(54)-RNAP. The stoichiometry between these three elements defines natural system boundaries that outline a specific functional space. This space can be expanded artificially following different strategies that involve either the increase of XylR or σ(54) or both elements at the same time (each using a different inducer). In this work we have designed a new regulatory architecture that drives the system to reach a maximum performance in response to one single input. To this end, we first explored using a simple mathematical model whether the output of the XylR/Pu node could be amended by simultaneously increasing σ(54) and XylR in response to only natural inducers. The exacerbation of Pu activity in vivo was tested in strains bearing synthetic transposons encoding xylR and rpoN (the σ(54) coding gene) controlled also by Pu, thereby generating a P. putida strain with the XylR/Pu output controlled by two intertwined feed forward loops (FFLs). The lack of a negative feedback loop in the expression node enables Pu activity to reach its physiological maximum in response to a single input. Only competition for cell resources might ultimately check the upper activity limit of such a rewired m-xylene sensing device.

  2. Rationally rewiring the connectivity of the XylR/Pu regulatory node of the m-xylene degradation pathway in Pseudomonas putida.

    Science.gov (United States)

    de Las Heras, Aitor; Martínez-García, Esteban; Domingo-Sananes, Maria Rosa; Fraile, Sofia; de Lorenzo, Víctor

    2016-04-18

    The XylR/Pu regulatory node of the m-xylene biodegradation pathway of Pseudomonas putida mt-2 is one of the most intricate cases of processing internal and external cues into a single controlling element. Despite this complexity, the performance of the regulatory system is determined in vivo only by the occupation of Pu by m-xylene-activated XylR and σ(54)-RNAP. The stoichiometry between these three elements defines natural system boundaries that outline a specific functional space. This space can be expanded artificially following different strategies that involve either the increase of XylR or σ(54) or both elements at the same time (each using a different inducer). In this work we have designed a new regulatory architecture that drives the system to reach a maximum performance in response to one single input. To this end, we first explored using a simple mathematical model whether the output of the XylR/Pu node could be amended by simultaneously increasing σ(54) and XylR in response to only natural inducers. The exacerbation of Pu activity in vivo was tested in strains bearing synthetic transposons encoding xylR and rpoN (the σ(54) coding gene) controlled also by Pu, thereby generating a P. putida strain with the XylR/Pu output controlled by two intertwined feed forward loops (FFLs). The lack of a negative feedback loop in the expression node enables Pu activity to reach its physiological maximum in response to a single input. Only competition for cell resources might ultimately check the upper activity limit of such a rewired m-xylene sensing device. PMID:26961967

  3. One-pot reduction of 5-hydroxymethylfurfural via hydrogen transfer from supercritical methanol

    DEFF Research Database (Denmark)

    Hansen, Thomas Søndergaard; Barta, Katalin; Anastas, Paul T.;

    2012-01-01

    Catalytic conversion of HMF to valuable chemicals was achieved over a Cu-doped porous metal oxide in supercritical methanol. The hydrotalcite catalyst precursor is prepared following simple synthetic procedures, using inexpensive and earth-abundant starting materials in aqueous solutions. The hyd...

  4. Direct conversion of chitin biomass to 5-hydroxymethylfurfural in concentrated ZnCl2 aqueous solution

    DEFF Research Database (Denmark)

    Wang, Yingxiong; Pedersen, Christian Marcus; Deng, Tiansheng;

    2013-01-01

    of the reaction parameters including the screening of 8 co-catalysts was carried out. Among them, AlCl3 and B(OH)3 improved 5-HMF yield, whereas CdCl2, CuCl2 and NH4Cl had no effect. CrCl3, SnCl4 and SnCl2 showed negative effects, i.e. lower yields. Consequently, the optimal reaction conditions were found...

  5. Novel multispecies microbial consortia involved in lignocellulose and 5-hydroxymethylfurfural bioconversion

    NARCIS (Netherlands)

    Jiménez Avella, Diego; Korenblum, Elisa; van Elsas, Jan Dirk

    2014-01-01

    To develop a targeted metagenomics approach for the analysis of novel multispecies microbial consortia involved in the bioconversion of lignocellulose and furanic compounds, we applied replicated sequential batch aerobic enrichment cultures with either pretreated or untreated wheat straw as the sour

  6. Catalytic Response and Stability of Nickel/Alumina for the Hydrogenation of 5-Hydroxymethylfurfural in Water.

    Science.gov (United States)

    Perret, Noémie; Grigoropoulos, Alexios; Zanella, Marco; Manning, Troy D; Claridge, John B; Rosseinsky, Matthew J

    2016-03-01

    The catalytic response of Ni on Al2O3 obtained from Ni-Al layered double hydroxides was studied for the liquid-phase hydrogenation of hydroxymethyl furfural to tetrahydrofuran-2,5-diyldimethanol (THFDM) in water. The successive calcination and reduction of the precursors caused the removal of interlayer hydroxyl and carbonate groups and the reduction of Ni(2+) to Ni(0). Four reduced mixed oxide catalysts were obtained, consisting of different amount of Ni metal contents (47-68 wt%) on an Al-rich amorphous component. The catalytic activity was linked to Ni content whereas selectivity was mainly affected by reaction temperature. THFDM was formed in a stepwise manner at low temperature (353 K) whereas 3-hydroxymethyl cyclopentanone was generated at higher temperature. Coke formation caused deactivation; however, the catalytic activity can be regenerated using heat treatment. The results establish Ni on Al2O3 as a promising catalyst for the production of THFDM in water. PMID:26870940

  7. Catalytic Conversion of Glucose into 5-Hydroxymethylfurfural by Hf(OTf4 Lewis Acid in Water

    Directory of Open Access Journals (Sweden)

    Junjie Li

    2015-12-01

    Full Text Available A series of Lewis acidic metal salts were used for glucose dehydration to 5-hydroymethylfurfural (HMF in water. Effect of valence state, ionic radii of Lewis acidic cation, and the type of anions on the catalytic performance have been studied systematically. The experimental results showed that the valence state played an important role in determining catalytic activity and selectivity. It was found that a higher glucose conversion rate and HMF selectivity could be obtained over high valent Lewis acid salts, where the ionic radii of these Lewis acidic metal salts are usually relatively small. Analysis on the effect of the anions of Lewis acid salts on the catalytic activity and the selectivity suggested that a higher glucose conversion and HMF selectivity could be readily obtained with Cl−. Furthermore, the recyclability of high valence state Lewis acid salt was also studied, however, inferior catalytic performance was observed. The deactivation mechanism was speculated to be the fact that high valence state Lewis acid salt was comparatively easier to undergo hydrolysis to yield complicated metal aqua ions with less catalytic activity. The Lewis acidic activity could be recovered by introducing a stoichiometric amount of hydrochloric acid (HCl to the catalytic before the reaction.

  8. The Catalytic Conversion of D-Glucose to 5-Hydroxymethylfurfural in DMSO Using Metal Salts

    NARCIS (Netherlands)

    Rasrendra, C. B.; Soetedjo, J. N. M.; Makertihartha, I. G. B. N.; Adisasmito, S.; Heeres, H. J.; Albrecht, Karl O.; Holladay, Johnathan E.

    2012-01-01

    A wide range of metal halides and triflates were examined for the conversion of d-glucose to HMF in DMSO. Chromium and aluminium salts were identified as the most promising catalysts. The effect of process variables like initial d-glucose concentration (0.1-1.5 M), reaction time (5-360 min) and reac

  9. Metal Chlorides in Ionic Liquid Solvents Convert Sugars to 5-Hydroxymethylfurfural

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haibo; Holladay, John E.; Brown, Heather M.; Zhang, Z. Conrad

    2007-06-15

    Sugars were converted to hydroxymethylfurfural (HMF) at high yield in ionic liquids without the addition of Bronsted acids. Very small amount of certain metal halides significantly reduced the fructose dehydration barrier in ionic liquids producing HMF at high yields. Most remarkably, glucose, a common sugar molecule, was selectively converted to HMF in good yield in ionic liquids containing a small amount of CrCl2. Thus CrCl2 is unique among metal chlorides tested for its effectiveness in both isomerizing glucose as well as dehydrating fructose. Only negligble amount of levulinic acid was formed in the reactions. The catalytic activity of metal chlorides for sugar conversion in ionic liquids is perhaps related to hydroxyl group of the sugar forming metal complexes with the unsaturated metal center.

  10. Formation and relevance of 5-hydroxymethylfurfural in bioactive subcritical water extracts from olive leaves

    OpenAIRE

    Herrero, Miguel; Castro-Puyana, M.; Rocamora-Reverte, Lourdes; Ferragut, José A.; Cifuentes, Alejandro; Ibáñez, Elena

    2012-01-01

    Although subcritical water extraction (SWE) has already shown its great potential for the attainment of natural bioactive extracts, concerns still remain on possible unexpected reactions that can arise during the extraction process, usually taking place at high pressure and temperature. It is already well-known that different components might be formed during the SWE extraction protocol due e.g. to Maillard reaction, which can improve the bioactivity of the obtained extracts. On the other han...

  11. Degradation of co-activator Yki of the hippo pathway through ubiquitinationby Slimb%Slimb通过泛素化降解hippo信号通路的辅转录因子Yki

    Institute of Scientific and Technical Information of China (English)

    郭纪伟; 金丹

    2015-01-01

    Yki,an important co-transcription factor,regulates the expression of downstream target genes of the hippo pathway.Yki is known to be important for development,growth,organogenesis and maintenance of adult stem cells. Slimb as a substrate specificity subunit of the SCF E3 ubiquitin ligase promotes proteins for degradation in the drosophi-la.In this paper,we found that Slimb degraded Yki by the ubiquitination and the co-immunoprecipitation indicated that Slimb interacted with Yki in vitro.Furthermore,we found that co-overexpression with Slimb caused mostly suppressed Yki wing phenotype and knockdown of Slimb enhanced overexpression with Yki eye phenotype.These results suggested that Slimb as a subunit of the E3 ubiquitin ligase regulated the stability of Yki and provided an important significance in the regulating tissue growth and development of hippo pathway.%Yki是hippo信号通路中主要的基因转录辅助因子,调节下游靶基因的表达。它在细胞生长分化、组织器官形成以及成体干细胞维持等方面都起着重要的作用。在果蝇中,Slimb是SCF E3泛素连接复合物中的亚基,具有底物专一性,特异性地降解蛋白质。本研究中发现,在体外Slimb能够通过泛素化降解Yki。进一步利用免疫共沉淀的方法,发现Slimb与Yki能够相互作用。果蝇中过表达yki产生的表型能够被同时过表达Slimb所恢复,被Slimb沉默所加剧。这些研究结果提示Slimb作为E3连接酶的一个亚基,可以调节Yki的稳定性,在研究hippo信号通路调节组织生长发育中具有重要的意义。

  12. Bacterial degradation of fungicide captan.

    Science.gov (United States)

    Megadi, Veena B; Tallur, Preeti N; Mulla, Sikandar I; Ninnekar, Harichandra Z

    2010-12-22

    The phthalimide fungicide captan has been widely used to control plant pathogenic fungi. A strain of Bacillus circulans utilized the fungicide captan as sole source of carbon and energy. The organism degraded captan by a pathway involving its initial hydrolysis to yield cis-1,2,3,6-tetrahydrophthalimide, a compound without fungicidal activity. The formation of this compound was confirmed by HPLC, IR, NMR, and mass spectral analysis. The results also revealed that cis-1,2,3,6-tetrahydrophthalimide was further degraded to o-phthalic acid by a protocatechuate pathway. These findings indicated that there was a complete mineralization of fungicide captan by B. circulans.

  13. Metabolic pathway involved in 2-methyl-6-ethylaniline degradation by Sphingobium sp. strain MEA3-1 and cloning of the novel flavin-dependent monooxygenase system meaBA.

    Science.gov (United States)

    Dong, Weiliang; Chen, Qiongzhen; Hou, Ying; Li, Shuhuan; Zhuang, Kai; Huang, Fei; Zhou, Jie; Li, Zhoukun; Wang, Jue; Fu, Lei; Zhang, Zhengguang; Huang, Yan; Wang, Fei; Cui, Zhongli

    2015-12-01

    2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02' in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase.

  14. Metabolic Pathway Involved in 2-Methyl-6-Ethylaniline Degradation by Sphingobium sp. Strain MEA3-1 and Cloning of the Novel Flavin-Dependent Monooxygenase System meaBA

    Science.gov (United States)

    Dong, Weiliang; Chen, Qiongzhen; Hou, Ying; Li, Shuhuan; Zhuang, Kai; Huang, Fei; Zhou, Jie; Li, Zhoukun; Wang, Jue; Fu, Lei; Zhang, Zhengguang; Huang, Yan; Wang, Fei

    2015-01-01

    2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02′ in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase. PMID:26386060

  15. TALSPEAK Solvent Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Leigh R. Martin; Bruce J. Mincher

    2009-09-01

    Understanding the radiolytic degradation behavior of organic molecules involved in new or existing schemes for the recycle of used nuclear fuels is of significant interest for sustaining a closed nuclear fuel cycle. Here we have conducted several lines of investigation to begin understanding the effects of radiolysis on the aqueous phase of the TALSPEAK process for the separation of the trivalent lanthanides from the trivalent actinides. Using the 60-Co irradiator at the INL, we have begun to quantify the effects of radiation on the aqueous phase complexants used in this separation technique, and how this will affect the actinide lanthanide separation factor. In addition we have started to develop methodologies for stable product identification, a key element in determining the degradation pathways. We have also introduced a methodology to investigate the effects of alpha radiolysis that has previously received limited attention.

  16. Study on the treatment of chlorpyrifos wastewater by ultrasonic electro-coagulation and degradation pathway analysis%超声-电凝聚技术处理毒死蜱废水研究及降解途径分析

    Institute of Scientific and Technical Information of China (English)

    钱佳燕; 王玲; 薛建军; 蔡燕华; 周凝; 黄明喜

    2012-01-01

    According to the disadvantages of chlorpyrifos wastewater such as serious pollution 'and poor biodegradability, the treatment of chlorpyrifos wastewater by ultrasonic electro-coagulation was studied. In this research work, the effects of various parameters were investigated including voltage, ultrasonic power, initial organic phosphorus concentration and flowing rate. The energy consumption of removing chlorpyrifos by ultrasonic electro-coagulation method was discussed. The possible oxidative degradation pathway of chlorpyrifos in, wastewater was also derived. The results showed that for the waste water with organic phosphorus concentration of 10 mg · L-1, when the flowing rate was 250mL·min-1, the optimum voltage was 9V and ultrasonic power was 80W. At optimum condition, the removal efficiency of organic phosphorus and CODcr was 99.84%, 95.44% after 15min, respectively.%针对毒死蜱废水污染严重、可生化性差的特点,本实验研究了超声-电凝聚方法处理毒死蜱废水的效果.通过单因素实验探讨了电压、超声功率、原水初始有机磷浓度和流速等因素对超声-电凝聚法去除有机磷及CODCr效果的影响,并进行了能耗分析及毒死蜱降解途径分析.结果表明:最佳工艺条件为电压9V,超声功率80W、原水初始有机磷浓度10mg·L-1、流速250mL·min-1.在最佳条件下,电解15min后,有机磷的去除率达到99.84%,CODCr的去除率达到95.44%.

  17. Ordered bulk degradation via autophagy

    DEFF Research Database (Denmark)

    Dengjel, Jörn; Kristensen, Anders Riis; Andersen, Jens S

    2008-01-01

    During amino acid starvation, cells undergo macroautophagy which is regarded as an unspecific bulk degradation process. Lately, more and more organelle-specific autophagy subtypes such as reticulophagy, mitophagy and ribophagy have been described and it could be shown, depending on the experimental...... setup, that autophagy specifically can remove certain subcellular components. We used an unbiased quantitative proteomics approach relying on stable isotope labeling by amino acids in cell culture (SILAC) to study global protein dynamics during amino acid starvation-induced autophagy. Looking...... at proteasomal and lysosomal degradation ample cross-talk between the two degradation pathways became evident. Degradation via autophagy appeared to be ordered and regulated at the protein complex/organelle level. This raises several important questions such as: can macroautophagy itself be specific and what...

  18. Single gene retrieval from thermally degraded DNA

    Indian Academy of Sciences (India)

    Lianwen Zhang; Lianwen Zhang

    2005-12-01

    To simulate single gene retrieval from ancient DNA, several related factors have been investigated. By monitoring a 889 bp polymerase chain reaction (PCR) product and genomic DNA degradation, we find that heat and oxygen (especially heat) are both crucial factors influencing DNA degradation. The heat influence, mainly represented by temperature and heating time, affects the DNA degradation via DNA depurination followed by cleavage of nearby phosphodiesters. The heating time influence is temperature-dependent. By reactive oxygen species (ROS) scavenging and 1,3-diphenyl-isobenzofuran (DPBF) bleaching experiments the influence of oxygen on DNA thermal degradation was shown to occur via a singlet oxygen pathway. A comparative study of the thermal degradation of cellular DNA and isolated DNA showed that cellular lipids can aggravate DNA thermal degradation. These results confirm the possibility of gene amplification from thermally degraded DNA. They can be used to evaluate the feasibility of the retrieval of single gene from ancient remains.

  19. Delineation of Steroid-Degrading Microorganisms through Comparative Genomic Analysis

    Directory of Open Access Journals (Sweden)

    Lee H. Bergstrand

    2016-03-01

    Full Text Available Steroids are ubiquitous in natural environments and are a significant growth substrate for microorganisms. Microbial steroid metabolism is also important for some pathogens and for biotechnical applications. This study delineated the distribution of aerobic steroid catabolism pathways among over 8,000 microorganisms whose genomes are available in the NCBI RefSeq database. Combined analysis of bacterial, archaeal, and fungal genomes with both hidden Markov models and reciprocal BLAST identified 265 putative steroid degraders within only Actinobacteria and Proteobacteria, which mainly originated from soil, eukaryotic host, and aquatic environments. These bacteria include members of 17 genera not previously known to contain steroid degraders. A pathway for cholesterol degradation was conserved in many actinobacterial genera, particularly in members of the Corynebacterineae, and a pathway for cholate degradation was conserved in members of the genus Rhodococcus. A pathway for testosterone and, sometimes, cholate degradation had a patchy distribution among Proteobacteria. The steroid degradation genes tended to occur within large gene clusters. Growth experiments confirmed bioinformatic predictions of steroid metabolism capacity in nine bacterial strains. The results indicate there was a single ancestral 9,10-seco-steroid degradation pathway. Gene duplication, likely in a progenitor of Rhodococcus, later gave rise to a cholate degradation pathway. Proteobacteria and additional Actinobacteria subsequently obtained a cholate degradation pathway via horizontal gene transfer, in some cases facilitated by plasmids. Catabolism of steroids appears to be an important component of the ecological niches of broad groups of Actinobacteria and individual species of Proteobacteria.

  20. Polysaccharide Degradation

    Science.gov (United States)

    Stone, Bruce A.; Svensson, Birte; Collins, Michelle E.; Rastall, Robert A.

    An overview of current and potential enzymes used to degrade polysaccharides is presented. Such depolymerases are comprised of glycoside hydrolases, glycosyl transferases, phosphorylases and lyases, and their classification, active sites and action patterns are discussed. Additionally, the mechanisms that these enzymes use to cleave glycosidic linkages is reviewed as are inhibitors of depolymerase activity; reagents which react with amino acid residues, glycoside derivatives, transition state inhibitors and proteinaceous inhibitors. The characterization of various enzymes of microbial, animal or plant origin has led to their widespread use in the production of important oligosaccharides which can be incorporated into food stuffs. Sources of polysaccharides of particular interest in this chapter are those from plants and include inulin, dextran, xylan and pectin, as their hydrolysis products are purported to be functional foods in the context of gastrointestinal health. An alternative use of degraded polysaccharides is in the treatment of disease. The possibility exists to treat bacterial exopolysaccharide with lyases from bacteriophage to produce oligosaccharides exhibiting bioactive sequences. Although this area is currently in its infancy the knowledge is available to investigate further.

  1. Mono-chlorophenol degradation by pseudomonas putida CP1 and a mixed microbial population

    OpenAIRE

    Farrell, Alan

    2000-01-01

    A commercial mixed culture, Biolyte HAB, degraded mono-chlorophenols using a metci- cleavage pathway. 2- and 3-chlorophenol degradation was incomplete, leading to the accumulation of dead-end metabolites. Biolyte HAB was capable of the complete degradation of 2.34 mM 4-chlorophenol, via the intermediate 5-chloro-2- hydroxymuconic semialdehyde, using the meta- cleavage pathway. Pseudomonas putida CPI degraded mono-chlorophenols to completion via an orthocleavage pathway. The ability of P. ...

  2. Degradation of Chlorinated Aromatic Compounds in UASB Reactors

    DEFF Research Database (Denmark)

    Christiansen, Nina; Hendriksen, Hanne Vang; Järvinen, Kimmo T.;

    1995-01-01

    Data on anaerobic degradation of chloroaromatic compounds in Upflow Anaerobic Sludge Blanket Reactors (UASB-reactor) are presented and compared. Special attention is given to the metabolic pathways for degradation of chlorinated phenols by granular sludge. Results indicate that PCP can be degraded...

  3. Sonolytic degradation of 2-chlorobiphenyl

    Institute of Scientific and Technical Information of China (English)

    张光明; 华天星; 常爱敏

    2004-01-01

    The sonolytic degradation of 2-chlorobiphenyl was investigated. Mass spectroscopy was used to detect the products of sonolytic degradation of 2-chlorobiphenyl. The results show that the products of sonolytic degradation, such as biphenyl, ethyl benzene, diethylbiphenyl, dibutylbiphenyl, phenol, propylphenol and di-tert-butyl phenol are produced by thermolysis and hydroxyl free radical reactions, in which biphenyl counts for almost 40%(mole fraction) of the mother compound and others are at trace level. Rapid accumulation of chloride ion shows quick dechlorination, and 78% organic chlorine is converted into chloride ion. Free radical scavengers, bicarbonate and carbonate, decrease the reaction rate of sonolytic degradation of 2-chlorobiphenyl significantly, and the pseudo 1st order rate constant of sonolytic degradation of 2-chlorobiphenyl decreases linearly with the natural logarithm of the concentration of the added free radical scavenger, showing that the pyrolysis and hydroxyl free radical reaction are the two major pathways for the sonolytic degradation of 2-chlorobiphenyl, in which the hydroxyl radical concentration is estimated to be 1 × 10 10mol/L.

  4. Thermal battery degradation mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunke, Lyle Brent [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Diffuse reflectance IR spectroscopy (DRIFTS) was used to investigate the effect of accelerated aging on LiSi based anodes in simulated MC3816 batteries. DRIFTS spectra showed that the oxygen, carbonate, hydroxide and sulfur content of the anodes changes with aging times and temperatures, but not in a monotonic fashion that could be correlated to phase evolution. Bands associated with sulfur species were only observed in anodes taken from batteries aged in wet environments, providing further evidence for a reaction pathway facilitated by H2S transport from the cathode, through the separator, to the anode. Loss of battery capacity with accelerated aging in wet environments was correlated to loss of FeS2 in the catholyte pellets, suggesting that the major contribution to battery performance degradation results from loss of active cathode material.

  5. Microbial Aspects of Anaerobic BTEX Degradation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Combined with conventional methods, developments in both geochemical (delineation of redox processes) and molecular microbial methods (analysis of 16S rDNA genes and functional genes) have allowed us to study in details microorganisms and genes involved in the anaerobic degradation of benzene, toluene, ethylbenzene and xylene (BTEX) under specific redox conditions. This review summarizes recent research in this field. The potential for anaerobic BTEX degradation is widely spread. Specific groups of microorganisms appear to be involved in degradation under different redox conditions. Members of the Azoarcus/Thauera cluster perform BTEX degradation under denitrifying conditions, Geobacteraceae under Fe (III) reducing conditions and Desulfobacteriaceae under sulfate reducing conditions. The information so far obtained on biochemistry and molecular genetics of BTEX degradation indicates that each BTEX compound is funneled into the central benzyol-CoA pathway by a different peripheral pathway. The peripheral pathways of per BTEX compound show similarities among different physiological groups of microorganisms. We also describe how knowledge obtained on the microbial aspects of BTEX degradation can be used to enhance and monitor anaerobic BTEX degradation.

  6. Trichloroethylene metabolism by microorganisms that degrade aromatic compounds.

    OpenAIRE

    1988-01-01

    Trichloroethylene (TCE) was metabolized by the natural microflora of three different environmental water samples when stimulated by the addition of either toluene or phenol. Two different strains of Pseudomonas putida that degrade toluene by a pathway containing a toluene dioxygenase also metabolized TCE. A mutant of one of these strains lacking an active toluene dioxygenase could not degrade TCE, but spontaneous revertants for toluene degradation also regained TCE-degradative ability. The re...

  7. Degradation of triclocarban by a triclosan-degrading Sphingomonas sp. strain YL-JM2C.

    Science.gov (United States)

    Mulla, Sikandar I; Hu, Anyi; Wang, Yuwen; Sun, Qian; Huang, Shir-Ly; Wang, Han; Yu, Chang-Ping

    2016-02-01

    Bacterial degradation plays a vital role in determining the environmental fate of micropollutants like triclocarban. The mechanism of triclocarban degradation by pure bacterium is not yet explored. The purpose of this study was to identify metabolic pathway that might be involved in bacterial degradation of triclocarban. Triclosan-degrading Sphingomonas sp. strain YL-JM2C was first found to degrade up to 35% of triclocarban (4 mg L(-1)) within 5 d. Gas chromatography-mass spectrometry detected 3,4-dichloroaniline, 4-chloroaniline and 4-chlorocatechol as the major metabolites of the triclocarban degradation. Furthermore, total organic carbon results confirmed that the intermediates, 3,4-dichloroaniline (4 mg L(-1)) and 4-chloroaniline (4 mg L(-1)) could be degraded up to 77% and 80% by strain YL-JM2C within 5 d.

  8. Degradation of triclocarban by a triclosan-degrading Sphingomonas sp. strain YL-JM2C.

    Science.gov (United States)

    Mulla, Sikandar I; Hu, Anyi; Wang, Yuwen; Sun, Qian; Huang, Shir-Ly; Wang, Han; Yu, Chang-Ping

    2016-02-01

    Bacterial degradation plays a vital role in determining the environmental fate of micropollutants like triclocarban. The mechanism of triclocarban degradation by pure bacterium is not yet explored. The purpose of this study was to identify metabolic pathway that might be involved in bacterial degradation of triclocarban. Triclosan-degrading Sphingomonas sp. strain YL-JM2C was first found to degrade up to 35% of triclocarban (4 mg L(-1)) within 5 d. Gas chromatography-mass spectrometry detected 3,4-dichloroaniline, 4-chloroaniline and 4-chlorocatechol as the major metabolites of the triclocarban degradation. Furthermore, total organic carbon results confirmed that the intermediates, 3,4-dichloroaniline (4 mg L(-1)) and 4-chloroaniline (4 mg L(-1)) could be degraded up to 77% and 80% by strain YL-JM2C within 5 d. PMID:26364219

  9. Identification of an Acetochlor-degrading Strain M-3 and the Preliminary Metabolic Pathway%一株乙草胺降解菌株M-3的分离鉴定及其代谢途径的初步研究

    Institute of Scientific and Technical Information of China (English)

    金雷; 郭远明; 陈雪昌; 鲍静姣; 宋凯

    2013-01-01

    乙草胺是一种广谱、高效的酰胺类除草剂,由于乙草胺具有较长的降解周期,还有不易挥发、不易光解、易残留的特点,如果过量、频繁使用,对人、动植物均有一定的毒害作用.为了探讨乙草胺的微生物降解机理,本研究从长期受乙草胺污染的土壤中分离到一株能降解乙草胺的菌株M-3,该菌株能以乙草胺为唯一碳源生长.通过菌落表型、生理生化特征和菌株16S rRNA基因序列的相似性分析,将其鉴定为寡养单胞菌属(Stenotrophomonas sp.).在室内条件下,运用HPLC和HPLC-MS分析方法,研究了菌株M-3对乙草胺的降解特性,并对其代谢途径做了初步的研究.结果表明,菌株M-3在5d内对浓度为50 mg/L的乙草胺的降解率可达76.6%.M-3降解乙草胺的最适温度和最适pH值分别为30C和7.0.在对代谢产物结果进行分析的基础上推测了M-3降解乙草胺的途径,将产物鉴定为2-乙基-6-甲基-2-氯乙酰苯胺.该研究为乙草胺污染的生物修复提供了理论依据.%Acetochlor is a broad-spectrum and high-efficive chloroacetanilide herbicide.Because of its long degradation period,with the characteristics of difficult for volatilization,photolysis,and easy for residue,the overuse of acetochlor is toxic to human,plants and animals.In order to investigate the microbial degradation mechanisms of acetochlor,an acetochlor-degrading bacterium,named strain M-3 was isolated from acetochlor-contaminated samples using selective culture medium with acetochlor as the sole carbon source.The sWain was identified based on its morphological,physiological and biochemical tests,with reference to Bergey's Manual of Determinative Bacteriology combined with 16S rRNA gene sequence analysis.SWain M-3 was finally identified as Stenotrophomonas sp..With HPLC and HPLC-MS method,degrading characteristics of strain M-3 were studied under laboratory conditions and the degrading pathway of acetochlor was researched

  10. Phenoxyacetic acid degradation by the 2,4-dichlorophenoxyacetic acid (TFD) pathway of plasmid pJP4: mapping and characterization of the TFD regulatory gene, tfdR.

    OpenAIRE

    Harker, A R; Olsen, R H; Seidler, R J

    1989-01-01

    Plasmid pJP4 enables Alcaligenes eutrophus JMP134 to degrade 3-chlorobenzoate and 2,4-dichlorophenoxyacetic acid (TFD). Plasmid pRO101 is a derivative of pJP4 obtained by insertion of Tn1721 into a nonessential region of pJP4. Plasmid pRO101 was transferred by conjugation to several Pseudomonas strains and to A. eutrophus AEO106, a cured isolate of JMP134. AEO106(pRO101) and some Pseudomonas transconjugants grew on TFD. Transconjugants with a chromosomally encoded phenol hydroxylase also degr...

  11. Plasmids and aromatic degradation in Sphingomonas for bioremediation : Aromatic ring cleavage genes in soil and rhizosphere

    OpenAIRE

    SipilÀ, Timo

    2009-01-01

    Microbial degradation pathways play a key role in the detoxification and the mineralization of polyaromatic hydrocarbons (PAHs), which are widespread pollutants in soil and constituents of petroleum hydrocarbons. In microbiology the aromatic degradation pathways are traditionally studied from single bacterial strains with capacity to degrade certain pollutant. In soil the degradation of aromatics is performed by a diverse community of micro-organisms. The aim of this thesis was to study biode...

  12. SLUG FLOW PROCESSING IN MICROREACTORS FOR BIO-BASED CHEMICAL MANUFACTURING: SYNTHESIS AND OXIDATION OF 5-HYDROXYMETHYLFURFURAL AS POTENTIAL APPLICATIONS

    NARCIS (Netherlands)

    Yue, Jun; Deuss, Peter; Zhang, Zheng; Hommes, Arne; Heeres, Hero

    2016-01-01

    The ever increasing global demand on fossil resources that are limited in reserves has directed numerous research efforts recently towards the development of more sustainable feedstocks as the source for the production of fuels, chemicals and (performance) materials. Conversion of biomass (particula

  13. Over-expression of a putative oxidoreductase (UcpA) for increasing furfural or 5-hydroxymethylfurfural tolerance

    Science.gov (United States)

    Wang, Xuan; Miller, Elliot N.; Yomano, Lorraine P.; Shanmugam, Keelnatham T.; Ingram, Lonnie O'Neal

    2016-05-24

    The subject invention pertains to overexpression of a putative oxidoreductase (ucpA) for increasing furfural tolerance in genetically modified microorganisms. Genetically modified microorganisms capable of overexpressing UcpA are also provided. Increased expression of ucpA was shown to increase furfural tolerance by 50%, and to permit the fermentation of sugars to products in the presence of 15 mM furfural.

  14. Purification of biomass-derived 5-hydroxymethylfurfural and its catalytic conversion to 2,5-furandicarboxylic Acid.

    Science.gov (United States)

    Yi, Guangshun; Teong, Siew Ping; Li, Xiukai; Zhang, Yugen

    2014-08-01

    A simple and effective water extraction method is presented for the purification 5-hydroxylmethylfurfural (HMF) obtained from a biomass dehydration system. Up to 99% of the HMF can be recovered and the HMF in aqueous solution is directly converted to 2,5-furandicarboxylic acid (FDCA) as the sole product. This purification technique allows an integrated process to produce FDCA from fructose via HMF prepared in an isopropanol monophasic system, with an overall FDCA yield of 83% obtained. From Jerusalem raw artichoke biomass to FDCA via HMF prepared in a water/MIBK (methyl isobutyl ketone) biphasic system, an overall FDCA yield of 55% is obtained. PMID:24889713

  15. Research Progress in Microbiological Degradation of Bensulfuron-Methyl Herbicide

    Institute of Scientific and Technical Information of China (English)

    XIONG Minghua; LI Chunyan

    2009-01-01

    This paper reviewed the strategies and methods of screening for microorganisms having strong ability to remove bensulfuron-methyl (BSM), and discussed BSM degradation pathways and factors affecting its microbial metabolism. Finally, it prospected the research emphasis in the future.

  16. Comparative genetic organization of incompatibility group P degradative plasmids.

    OpenAIRE

    Burlage, R S; Bemis, L A; Layton, A C; Sayler, G. S.; Larimer, F

    1990-01-01

    Plasmids that encode genes for the degradation of recalcitrant compounds are often examined only for characteristics of the degradative pathways and ignore regions that are necessary for plasmid replication, incompatibility, and conjugation. If these characteristics were known, then the mobility of the catabolic genes between species could be predicted and different catabolic pathways might be combined to alter substrate range. Two catabolic plasmids, pSS50 and pSS60, isolated from chlorobiph...

  17. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  18. Investigating the control of chlorophyll degradation by genomic correlation mining

    Science.gov (United States)

    Chlorophyll degradation is an intricate process that is critical in a variety of plant tissues at different times during the plant life cycle. Many of the photoactive chlorophyll degradation intermediates are exceptionally cytotoxic necessitating that the pathway be carefully coordinated and regulat...

  19. Sugar utilization in the hyperthermophilic, sulfate-reducing archaeon Archaeoglobus fulgidus strain 7324: starch degradation to acetate and CO2 via a modified Embden-Meyerhof pathway and acetyl-CoA synthetase (ADP-forming).

    Science.gov (United States)

    Labes, A; Schönheit, P

    2001-11-01

    The hyperthermophilic, sulfate-reducing archaeon Archaeoglobus fulgidus strain 7324, rather than the type strain VC16, was found to grow on starch and sulfate as energy and carbon source. Fermentation products and enzyme activities were determined in starch-grown cells and compared to those of cells grown on lactate and sulfate. During exponential growth on starch, 1 mol of glucose-equivalent was incompletely oxidized with sulfate to approximately 2 mol acetate, 2 mol CO2 and 1 mol H2S. Starch-grown cells did not contain measurable amounts of the deazaflavin factor F420 (reducer A. fulgidus strain 7324 converts starch to acetate via a modified Embden-Meyerhof pathway and acetyl-CoA synthetase (ADP-forming). This is the first report of growth of a sulfate reducer on starch, i.e. on a polymeric sugar.

  20. Aerobic Degradation of Trichloroethylene by Co-Metabolism Using Phenol and Gasoline as Growth Substrates

    OpenAIRE

    Yan Li; Bing Li; Cui-Ping Wang; Jun-Zhao Fan; Hong-Wen Sun

    2014-01-01

    Trichloroethylene (TCE) is a common groundwater contaminant of toxic and carcinogenic concern. Aerobic co-metabolic processes are the predominant pathways for TCE complete degradation. In this study, Pseudomonas fluorescens was studied as the active microorganism to degrade TCE under aerobic condition by co-metabolic degradation using phenol and gasoline as growth substrates. Operating conditions influencing TCE degradation efficiency were optimized. TCE co-metabolic degradation rate reached ...

  1. PEM fuel cell degradation

    Energy Technology Data Exchange (ETDEWEB)

    Borup, Rodney L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory

    2010-01-01

    The durability of PEM fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. While significant progress has been made in understanding degradation mechanisms and improving materials, further improvements in durability are required to meet commercialization targets. Catalyst and electrode durability remains a primary degradation mode, with much work reported on understanding how the catalyst and electrode structure degrades. Accelerated Stress Tests (ASTs) are used to rapidly evaluate component degradation, however the results are sometimes easy, and other times difficult to correlate. Tests that were developed to accelerate degradation of single components are shown to also affect other component's degradation modes. Non-ideal examples of this include ASTs examining catalyst degradation performances losses due to catalyst degradation do not always well correlate with catalyst surface area and also lead to losses in mass transport.

  2. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

    Full Text Available Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic compounds has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  3. Molecular pathways

    DEFF Research Database (Denmark)

    Cox, Thomas R; Erler, Janine Terra

    2014-01-01

    45% of deaths in the developed world are linked to fibrotic disease. Fibrosis and cancer are known to be inextricably linked; however, we are only just beginning to understand the common and overlapping molecular pathways between the two. Here, we discuss what is known about the intersection of...... fibrosis and cancer, with a focus on cancer metastasis, and highlight some of the exciting new potential clinical targets that are emerging from analysis of the molecular pathways associated with these two devastating diseases. Clin Cancer Res; 20(14); 3637-43. ©2014 AACR....

  4. Degradation of microbial polyesters.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P

    2004-08-01

    Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB. PMID:15289671

  5. Degradation kinetics and mechanisms of phenolin photo-Fenton process

    Institute of Scientific and Technical Information of China (English)

    何锋; 雷乐成

    2004-01-01

    Phenol degradation in photochemically enhanced Fenton process was investigated in this work. UV-VIS spectra of phenol degradation showed the difference between photo-Fenton process and UV/H2O2, which is a typical hydroxyl radical process. A possible pathway diagram for phenol degradation in photo-Fenton process was proposed, and a mathematical model for chemical oxygen demand (COD) removal was developed. Operating parameters such as dosage of H2O2 and ferrous ions, pH, suitable carrier gas were found to impact the removal of COD significantly. The results and analysis of kinetic parameters calculated from the kinetic model showed that complex degradation of phenol was the main pathway for removal of COD: while hydroxyl radicals acted weakly in the photo-Fenton degradation of phenol.

  6. INTERMITTENT DEGRADATION AND SCHIZOTYPY

    OpenAIRE

    Roché, Matthew W.; Silverstein, Steven M.; Lenzenweger, Mark F.

    2015-01-01

    Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy) is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-repo...

  7. Heat Shock Proteins Regulate Activation-induced Proteasomal Degradation of the Mature Phosphorylated Form of Protein Kinase C*

    OpenAIRE

    Lum, Michelle A.; Balaburski, Gregor M; Murphy, Maureen E.; Black, Adrian R.; Black, Jennifer D.

    2013-01-01

    Background: Mechanisms of activation-induced PKC down-regulation are poorly understood. A characterized pathway involves priming site dephosphorylation and degradation of the dephosphorylated species.

  8. Phylogenetic and degradation characterization of Burkholderia cepacia WZ1 degrading herbicide quinclorac.

    Science.gov (United States)

    Lü, Zhenmei; Min, Hang; Wu, Shuwen; Ruan, Aidong

    2003-11-01

    Strain WZI capable of degrading quinclorac was isolated from a pesticide manufactory soil and considered to be Burkholderia cepacia, belonged to bacteria, Proteobacteria, beta-Proteobacteria, based on morphology, physio-biochemical properties, whole cell fatty acid analysis and a partial sequencing of 16S rDNA. Strain WZ1 decomposed 90% of quinclorac at original concentration of 1000 mg L(-1) within 11 days. GC/MS analysis showed that the strain degraded quinclorac to 3,7-dichloro-8-quinoline and the cracked residue 2-chloro, 1,4-benzenedicarboxylic acid, indicating that the metabolic pathway was initiated by process of decarboxylation followed by cleavage of the aromatic ring. Stain WZ1 was also able to degrade some other herbicides and aromatic compounds, including 2,4,5-T, phenol, naphthalene and hydrochinone etc. This paper describes for the first time Phylogenetic and degradation characterization of a pure bacterium which, is able to mineralize quinclorac.

  9. Minireview: Selective Degradation of Mitochondria by Mitophagy*

    OpenAIRE

    Kim, Insil; Rodriguez-Enriquez, Sara; Lemasters, John J.

    2007-01-01

    Mitochondria are the essential site of aerobic energy production in eukaryotic cells. Reactive oxygen species (ROS) are an inevitable by-product of mitochondria metabolism and can cause mitochondrial DNA mutations and dysfunction. Mitochondrial damage can also be the consequence of disease processes. Therefore, maintaining a healthy population of mitochondria is essential to the well-being of cells. Autophagic delivery to lysosomes is the major degradative pathway in mitochondrial turnover, a...

  10. Prediction of drug degradants using DELPHI: an expert system for focusing knowledge.

    Science.gov (United States)

    Pole, David L; Ando, Howard Y; Murphy, Sean T

    2007-01-01

    DELPHI is an expert system that has been developed to predict possible degradants of pharmaceutical compounds under stress testing conditions. It has been programmed with the objective of finding relevant degradation pathways, identifying degradant structures, and providing tools to the analytical chemist to assist in degradation identification. The system makes degradant predictions based on the chemical structure of the drug molecule and precedent from a broad survey of the literature. A description of DELPHI's treatment of molecular perception is described as are many features of the heuristic degradation rules it uses to capture and apply chemical degradation knowledge. DELPHI's utility for capturing institutional knowledge is discussed in relation to an analysis of degradation prediction results for 250 molecules of diverse chemical structure collected over 5 years of use. As such, it provides a reliable, convenient, and rapid tool for evaluating potential pathways of chemical instability of pharmaceuticals. PMID:17602568

  11. Degradations and Rearrangement Reactions

    Science.gov (United States)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  12. Rate of NDF degradation

    DEFF Research Database (Denmark)

    Weisbjerg, Martin Riis; Koukolová, V; Lund, Peter

    2007-01-01

    Degradation profiles for NDF were estimated for 83 samples of grass/grass-clover, 27 samples of cereal whole crop and 14 samples of maize whole crop.......Degradation profiles for NDF were estimated for 83 samples of grass/grass-clover, 27 samples of cereal whole crop and 14 samples of maize whole crop....

  13. Degradation of nitrobenzene in wastewater by γ-ray irradiation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-juan; FENG Shao-hong; YU Han-qing; LI Qian-rong

    2004-01-01

    The degradation of nitrobenzene(NB) by γ-ray irradiation was studied. The influences of dose rate and initial NB concentration were investigated in details. At a dose rate of 55 Gy/min, the degradation kinetics was pseudo-first-order at NB concentrations from 0.2 mmol/L to 4.0 mmol/L. At an initial NB concentration of 0.8 mmol/L, the degradation of NB at various dose rates also followed pseudo-first-order kinetics. Dissolved oxygen was found to have a positive effect on NB degradation. The degradation products were identified as nitrophenol, nitrosobenzene, and hydroquinone, and so on. Based on the product analysis, possible degradation pathways of nitrobenzene were proposed.

  14. Current Status on Biochemistry and Molecular Biology of Microbial Degradation of Nicotine

    Directory of Open Access Journals (Sweden)

    Raman Gurusamy

    2013-01-01

    Full Text Available Bioremediation is one of the most promising methods to clean up polluted environments using highly efficient potent microbes. Microbes with specific enzymes and biochemical pathways are capable of degrading the tobacco alkaloids including highly toxic heterocyclic compound, nicotine. After the metabolic conversion, these nicotinophilic microbes use nicotine as the sole carbon, nitrogen, and energy source for their growth. Various nicotine degradation pathways such as demethylation pathway in fungi, pyridine pathway in Gram-positive bacteria, pyrrolidine pathway, and variant of pyridine and pyrrolidine pathways in Gram-negative bacteria have been reported. In this review, we discussed the nicotine-degrading pathways of microbes and their enzymes and biotechnological applications of nicotine intermediate metabolites.

  15. Updates on p53: modulation of p53 degradation as a therapeutic approach

    OpenAIRE

    Dey, A; Verma, C S; LANE, D. P.

    2008-01-01

    The p53 pathway is aberrant in most human tumours with over 50% expressing mutant p53 proteins. The pathway is critically controlled by protein degradation. Here, we discuss the latest developments in the search for small molecules that can modulate p53 pathway protein stability and restore p53 activity for cancer therapy.

  16. Silk structure and degradation.

    Science.gov (United States)

    Liu, Bin; Song, Yu-wei; Jin, Li; Wang, Zhi-jian; Pu, De-yong; Lin, Shao-qiang; Zhou, Chan; You, Hua-jian; Ma, Yan; Li, Jin-min; Yang, Li; Sung, K L Paul; Zhang, Yao-guang

    2015-07-01

    To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk. PMID:25982316

  17. Structural Organization of Enzymes of the Phenylacetate Catabolic Hybrid Pathway

    Directory of Open Access Journals (Sweden)

    Andrey M. Grishin

    2015-06-01

    Full Text Available Aromatic compounds are the second most abundant class of molecules on the earth and frequent environmental pollutants. They are difficult to metabolize due to an inert chemical structure, and of all living organisms, only microbes have evolved biochemical pathways that can open an aromatic ring and catabolize thus formed organic molecules. In bacterial genomes, the phenylacetate (PA utilization pathway is abundant and represents the central route for degradation of a variety of organic compounds, whose degradation reactions converge at this pathway. The PA pathway is a hybrid pathway and combines the dual features of aerobic metabolism, i.e., usage of both oxygen to open the aromatic ring and of anaerobic metabolism—coenzyme A derivatization of PA. This allows the degradation process to be adapted to fluctuating oxygen conditions. In this review we focus on the structural and functional aspects of enzymes and their complexes involved in the PA degradation by the catabolic hybrid pathway. We discuss the ability of the central PaaABCE monooxygenase to reversibly oxygenate PA, the controlling mechanisms of epoxide concentration by the pathway enzymes, and the similarity of the PA utilization pathway to the benzoate utilization Box pathway and β-oxidation of fatty acids.

  18. Structural Organization of Enzymes of the Phenylacetate Catabolic Hybrid Pathway.

    Science.gov (United States)

    Grishin, Andrey M; Cygler, Miroslaw

    2015-06-12

    Aromatic compounds are the second most abundant class of molecules on the earth and frequent environmental pollutants. They are difficult to metabolize due to an inert chemical structure, and of all living organisms, only microbes have evolved biochemical pathways that can open an aromatic ring and catabolize thus formed organic molecules. In bacterial genomes, the phenylacetate (PA) utilization pathway is abundant and represents the central route for degradation of a variety of organic compounds, whose degradation reactions converge at this pathway. The PA pathway is a hybrid pathway and combines the dual features of aerobic metabolism, i.e., usage of both oxygen to open the aromatic ring and of anaerobic metabolism-coenzyme A derivatization of PA. This allows the degradation process to be adapted to fluctuating oxygen conditions. In this review we focus on the structural and functional aspects of enzymes and their complexes involved in the PA degradation by the catabolic hybrid pathway. We discuss the ability of the central PaaABCE monooxygenase to reversibly oxygenate PA, the controlling mechanisms of epoxide concentration by the pathway enzymes, and the similarity of the PA utilization pathway to the benzoate utilization Box pathway and β-oxidation of fatty acids.

  19. SPECIFIC DEGRADATION OF WATERSHEDS

    Institute of Scientific and Technical Information of China (English)

    Boubacar KANE; Pierre Y.JULIEN

    2007-01-01

    An extensive database of reservoir sedimentation surveys throughout continental United States is compiled and analyzed to determine specific degradation SD relationships as function of mean annual rainfall R, drainage area A, and watershed slope S. The database contains 1463 field measurements and specific degradation relationships are defined as function of A, R and S. Weak trends and significant variability in the data are noticeable. Specific degradation measurements are log normally distributed with respect to R, A, and S and 95% confidence intervals are determined accordingly. The accuracy of the predictions does not significantly increase as more independent variables are added to the regression analyses.

  20. Static analysis of a Model of the LDL degradation pathway

    DEFF Research Database (Denmark)

    Pilegaard, Henrik; Nielson, Flemming; Nielson, Hanne Riis

    2005-01-01

    BioAmbients is a derivative of mobile ambients that has shown promise of describing interesting features of the behaviour of biological systems. As for other ambient calculi static program analysis can be used to compute safe approximations of the behavior of modelled systems. We use these tools ...

  1. Engineering the spatial organization of metabolic pathways

    DEFF Research Database (Denmark)

    Albertsen, Line; Maury, Jerome; Bach, Lars Stougaard;

    or assembly into large complexes. The vision is that by positioning sequentially acting enzymes in close proximity, the cell can accelerate reaction rates and thereby prevent loss of intermediates through diffusion, degradation or competing pathways. The production of valuable metabolites in cell factories...

  2. IL-1β enhances cell adhesion to degraded fibronectin

    OpenAIRE

    Rajshankar, Dhaarmini; Downey, Gregory P.; McCulloch, Christopher A.

    2012-01-01

    IL-1β is a prominent proinflammatory cytokine that mediates degradation of extracellular matrix proteins through increased expression of matrix metalloproteinases, which involves a signaling pathway in adherent cells that is restricted by focal adhesions. Currently, the mechanism by which IL-1β affects cell adhesion to matrix proteins is not defined, and it is not known whether degraded matrix proteins affect IL-1β signaling. We examined adhesion-related IL-1β signaling in fibroblasts attachi...

  3. Curcumin inhibits HIV-1 by promoting Tat protein degradation

    OpenAIRE

    Amjad Ali; Banerjea, Akhil C

    2016-01-01

    HIV-1 Tat is an intrinsically unfolded protein playing a pivotal role in viral replication by associating with TAR region of viral LTR. Unfolded proteins are degraded by 20S proteasome in an ubiquitin independent manner. Curcumin is known to activate 20S proteasome and promotes the degradation of intrinsically unfolded p53 tumor suppressor protein. Since HIV-1 Tat protein is largerly unfolded, we hypothesized that Tat may also be targeted through this pathway. Curcumin treated Tat transfected...

  4. Purex diluent degradation

    Energy Technology Data Exchange (ETDEWEB)

    Tallent, O.K.; Mailen, J.C.; Pannell, K.D.

    1984-02-01

    The chemical degradation of normal paraffin hydrocarbon (NPH) diluents both in the pure state and mixed with 30% tributyl phosphate (TBP) was investigated in a series of experiments. The results show that degradation of NPH in the TBP-NPH-HNO/sub 3/ system is consistent with the active chemical agent being a radical-like nitrogen dioxide (NO/sub 2/) molecule, not HNO/sub 3/ as such. Spectrophotometric, gas chromatographic, mass spectrographic, and titrimetric methods were used to identify the degradation products, which included alkane nitro and nitrate compounds, alcohols, unsaturated alcohols, nitro alcohols, nitro alkenes, ketones, and carboxylic acids. The degradation rate was found to increase with increases in the HNO/sub 3/ concentration and the temperature. The rate was decreased by argon sparging to remove NO/sub 2/ and by the addition of butanol, which probably acts as a NO/sub 2/ scavenger. 13 references, 11 figures.

  5. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  6. Conceptualizing Forest Degradation.

    Science.gov (United States)

    Ghazoul, Jaboury; Burivalova, Zuzana; Garcia-Ulloa, John; King, Lisa A

    2015-10-01

    Forest degradation is a global environmental issue, but its definition is problematic. Difficulties include choosing appropriate reference states, timescales, thresholds, and forest values. We dispense with many such ambiguities by interpreting forest degradation through the frame of ecological resilience, and with reference to forest dynamics. Specifically, we define forest degradation as a state of anthropogenically induced arrested succession, where ecological processes that underlie forest dynamics are diminished or severely constrained. Metrics of degradation might include those that reflect ecological processes shaping community dynamics, notably the regeneration of plant species. Arrested succession implies that management intervention is necessary to recover successional trajectories. Such a definition can be applied to any forest ecosystem, and can also be extended to other ecosystems. PMID:26411619

  7. Bacterial Degradation of Pesticides

    DEFF Research Database (Denmark)

    Knudsen, Berith Elkær

    . Bioaugmentation i.e. addition of specific degrader organisms, has been suggested as an environmentally friendly and economically competitive strategy for cleaning polluted sites. Several organisms have been isolated, capable of degrading different compounds. However the capacity to degrade the desired compound...... could potentially improve bioremediation of BAM. An important prerequisite for bioaugmentation is the potential to produce the degrader strain at large quantities within reasonable time. The aim of manuscript II, was to optimize the growth medium for Aminobacter MSH1 and to elucidate optimal growth...... analysis revealed that D47 had an inhibitory effect on the fungal growth; however the effect on LEJ702 was lessened in presence of SRS16. This effect of SRS16 was not seen on LEJ703. These results stress the importance of testing the consortia, as it is impossible to predict the outcome of the created...

  8. Purex diluent degradation

    International Nuclear Information System (INIS)

    The chemical degradation of normal paraffin hydrocarbon (NPH) diluents both in the pure state and mixed with 30% tributyl phosphate (TBP) was investigated in a series of experiments. The results show that degradation of NPH in the TBP-NPH-HNO3 system is consistent with the active chemical agent being a radical-like nitrogen dioxide (NO2) molecule, not HNO3 as such. Spectrophotometric, gas chromatographic, mass spectrographic, and titrimetric methods were used to identify the degradation products, which included alkane nitro and nitrate compounds, alcohols, unsaturated alcohols, nitro alcohols, nitro alkenes, ketones, and carboxylic acids. The degradation rate was found to increase with increases in the HNO3 concentration and the temperature. The rate was decreased by argon sparging to remove NO2 and by the addition of butanol, which probably acts as a NO2 scavenger. 13 references, 11 figures

  9. [Degradation of succinylcholine chloride].

    Science.gov (United States)

    Németh, G; Török, I; Paál, T

    1993-05-01

    Quantitative thin-layer chormatographic method has been developed for the investigation of the degradation of injection formulations containing succinylcholinium chloride. The method is based on the denistometric determination of the main degradation product, choline at 430 nm after visualization with iodine vapour. The stability of the injection was investigated under various storage conditions and it has been stated that considerable decomposition takes place during as short a period as one week. PMID:8362654

  10. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  11. Degradation of various alkyl ethers by alkyl ether-degrading Actinobacteria isolated from activated sludge of a mixed wastewater treatment.

    Science.gov (United States)

    Kim, Yong-Hak; Cha, Chang-Jun; Engesser, Karl-Heinrich; Kim, Sang-Jong

    2008-11-01

    Various substrate specificity groups of alkyl ether (AE)-degrading Actinobacteria coexisted in activated sewage sludge of a mixed wastewater treatment. There were substrate niche overlaps including diethyl ether between linear AE- and cyclic AE-degrading strains and phenetole between monoalkoxybenzene- and linear AE-degrading strains. Representatives of each group showed different substrate specificities and degradation pathways for the preferred substrates. Determining the rates of initial reactions and the initial metabolite(s) from whole cell biotransformation helped us to get information about the degradation pathways. Rhodococcus sp. strain DEE5311 and Rhodococcus rhodochrous strain 117 both were able to degrade anisole and phenetole through aromatic 2-monooxygenation to form 2-alkoxyphenols. In contrast, diethyl ether-oxidizing strain DEE5311 capable of degrading a broad range of linear AE, dibenzyl ether and monoalkoxybenzenes initially transformed anisole and phenetole to phenol via direct O-dealkylation. Compared to this, cyclic AE-degrading Rhodococcus sp. strain THF100 preferred tetrahydrofuran (265 ± 35 nmol min(-1)mg(-1) protein) to diethyl ether (diethoxybenzene-degrading Rhodococcus sp. strain DEOB100 and Gordonia sp. strain DEOB200 transformed 1,3-/1,4-dialkoxybenzenes to 3-/4-alkoxyphenols by similar manners in the order of rates (nmol min(-1) mg(-1) protein): 1,4-diethoxybenzene (11.1 vs. 3.9)>1,4-dimethoxybenzene (1.6 vs. 2.6)>1,3-dimethoxybenzene (0.6 vs. 0.6). This study suggests that the AE-degrading Actinobacteria can orchestrate various substrate specificity responses to the degradation of various categories of AE pollutants in activated sludge communities.

  12. Development of forced degradation and stability indicating studies of drugs-A review

    Institute of Scientific and Technical Information of China (English)

    Blessy Mn; Ruchi D. Patel; Prajesh N. Prajapati; Y.K. Agrawal

    2014-01-01

    Forced degradation is a degradation of new drug substance and drug product at conditions more severe than accelerated conditions. It is required to demonstrate specificity of stability indicating methods and also provides an insight into degradation pathways and degradation products of the drug substance and helps in elucidation of the structure of the degradation products. Forced degradation studies show the chemical behavior of the molecule which in turn helps in the development of formulation and package. In addition, the regulatory guidance is very general and does not explain about the performance of forced degradation studies. Thus, this review discusses the current trends in performance of forced degradation studies by providing a strategy for conducting studies on degradation mechanisms and also describes the analytical methods helpful for development of stability indicating method.

  13. Kinetics and characteristics of phenanthrene degradation by a microbial consortium

    Institute of Scientific and Technical Information of China (English)

    Wang Jin; Xu Hongke; An Mingquan; Yan Guiwen

    2008-01-01

    The kinetics and characteristics of phenanthrene degradation by a microbial consortium W4 isolated from Henan Oilfield were investigated. The degradation percentage of solid phenanthrene at 200 mg/L in liquid medium after 6 days of incubation was higher than 95% under the condition of 37 ℃ and 120 r/min by this microbial consortium. The degradation of phenanthrene could be fitted to a first-order kinetic model with the half-life of 1.25 days. The optimum conditions for degradation of phenanthrene by consortium W4 were as follows: temperature about 37 ℃, pH from 6.0 to 7.0 and salinity about 8.0 g/L.It was concluded that microbial consortium W4 might degrade phenanthrene via both salicylic acid and o-phthalic acid pathways by analyzing products with GC-MS.

  14. Degradation kinetics and products of triazophos in intertidal sediment

    Institute of Scientific and Technical Information of China (English)

    LIN Kun-de; YUAN Dong-xing

    2005-01-01

    This work presents laboratory studies on the degradation of triazophos in intertidal sediment. The overall degradations were found to follow the first-order decay model. After being incubated for 6 d, the percentage of degradations of triazophos in unsterilized and sterilized sediments were 94.5% and 20.5%, respectively. Between the temperatures of 15℃ and 35℃, the observed degradation rate constant( kobsd ) enhanced as the incubation temperature increased. Triazophos in sediment degraded faster under aerobic condition than under anaerobic one. The water content of sediment had little influence on the degradation when it was in the range of 50%-100%. The values of kobsd decreased with increasing initial concentration of triazophos in sediment, which could result from the microorganism inhibition by triazophos. Four major degradation products, o, o-diethyl phosphorothioic acid, monoethyl phosphorothioic acid, phosphorothioic acid,and 1-phenyl-3-hydroxy-1,2,4-triazole, were tentatively identified as their corresponding trimethylsilyl derivatives with a gas chromatography-mass spectrometer. The possible degradation pathway of triazophos in intertidal sediment was proposed. The results revealed that triazophos in intertidal sediment was relatively unstable and could be easily degraded.

  15. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal stress. (3) The DRKBA

  16. Drift Degradation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    D. Kicker

    2004-09-16

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal

  17. Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Water

    Energy Technology Data Exchange (ETDEWEB)

    Kirchman, David L. [Univ. of Delaware, Lewes, DE (United States)

    2012-03-29

    The net flux of methane from methane hydrates and other sources to the atmosphere depends on methane degradation as well as methane production and release from geological sources. The goal of this project was to examine methane-degrading archaea and organic carbon oxidizing bacteria in methane-rich and methane-poor sediments of the Beaufort Sea, Alaska. The Beaufort Sea system was sampled as part of a multi-disciplinary expedition (Methane in the Arctic Shelf or MIDAS) in September 2009. Microbial communities were examined by quantitative PCR analyses of 16S rRNA genes and key methane degradation genes (pmoA and mcrA involved in aerobic and anaerobic methane degradation, respectively), tag pyrosequencing of 16S rRNA genes to determine the taxonomic make up of microbes in these sediments, and sequencing of all microbial genes (metagenomes ). The taxonomic and functional make-up of the microbial communities varied with methane concentrations, with some data suggesting higher abundances of potential methane-oxidizing archaea in methane-rich sediments. Sequence analysis of PCR amplicons revealed that most of the mcrA genes were from the ANME-2 group of methane oxidizers. According to metagenomic data, genes involved in methane degradation and other degradation pathways changed with sediment depth along with sulfate and methane concentrations. Most importantly, sulfate reduction genes decreased with depth while the anaerobic methane degradation gene (mcrA) increased along with methane concentrations. The number of potential methane degradation genes (mcrA) was low and inconsistent with other data indicating the large impact of methane on these sediments. The data can be reconciled if a small number of potential methane-oxidizing archaea mediates a large flux of carbon in these sediments. Our study is the first to report metagenomic data from sediments dominated by ANME-2 archaea and is one of the few to examine the entire microbial assemblage potentially involved in

  18. Quantitative response relationships between degradation rates and functional genes during the degradation of beta-cypermethrin in soil.

    Science.gov (United States)

    Yang, Zhong-Hua; Ji, Guo-Dong

    2015-12-15

    In the present study, the degradation mechanisms of beta-cypermethrin and its metabolites in soil were explored through the quantitative response relationships between the degradation rates and related functional genes. We found that the degradation rate of beta-cypermethrin was rapid in unsterilized soil but not in sterilized soil, which indicated that the degradation process is microbially based. Moreover, three metabolites (3-phenoxybenzoic acid, phenol and protocatechuic acid) were detected during the degradation process and used to identify the degradation pathway and functional genes related to the degradation process. The key rate-limiting functional genes were pytH and pobA, and the relative contributions of these genes to the degradation process were examined with a path analysis. The path analysis revealed that the genes pobA and pytH had the greatest direct effects on the degradation of beta-cypermethrin (pobA), alpha-cypermethrin (pobA), theta-cypermethrin (pytH) and 3-phenoxybenzoic acid (pytH).

  19. Degradation of fluorotelomer alcohols

    DEFF Research Database (Denmark)

    Ellis, David A; Martin, Jonathan W; De Silva, Amila O;

    2004-01-01

    Human and animal tissues collected in urban and remote global locations contain persistent and bioaccumulative perfluorinated carboxylic acids (PFCAs). The source of PFCAs was previously unknown. Here we present smog chamber studies that indicate fluorotelomer alcohols (FTOHs) can degrade....... The significance of the gas-phase peroxy radical cross reactions that produce PFCAs has not been recognized previously. Such reactions are expected to occur during the atmospheric degradation of all polyfluorinated materials, necessitating a reexamination of the environmental fate and impact of this important...... in the atmosphere to yield a homologous series of PFCAs. Atmospheric degradation of FTOHs is likely to contribute to the widespread dissemination of PFCAs. After their bioaccumulation potential is accounted for, the pattern of PFCAs yielded from FTOHs could account for the distinct contamination profile of PFCAs...

  20. Motor degradation prediction methods

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  1. PWR degraded core analysis

    International Nuclear Information System (INIS)

    A review is presented of the various phenomena involved in degraded core accidents and the ensuing transport of fission products from the fuel to the primary circuit and the containment. The dominant accident sequences found in the PWR risk studies published to date are briefly described. Then chapters deal with the following topics: the condition and behaviour of water reactor fuel during normal operation and at the commencement of degraded core accidents; the generation of hydrogen from the Zircaloy-steam and the steel-steam reactions; the way in which the core deforms and finally melts following loss of coolant; debris relocation analysis; containment integrity; fission product behaviour during a degraded core accident. (U.K.)

  2. Motor degradation prediction methods

    International Nuclear Information System (INIS)

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor's duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures

  3. Photovoltaic Degradation Risk: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D. C.; Kurtz, S. R.

    2012-04-01

    The ability to accurately predict power delivery over the course of time is of vital importance to the growth of the photovoltaic (PV) industry. Important cost drivers include the efficiency with which sunlight is converted into power, how this relationship changes over time, and the uncertainty in this prediction. An accurate quantification of power decline over time, also known as degradation rate, is essential to all stakeholders - utility companies, integrators, investors, and researchers alike. In this paper we use a statistical approach based on historical data to quantify degradation rates, discern trends and quantify risks related to measurement uncertainties, number of measurements and methodologies.

  4. Antifoam degradation testing

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Zamecnik, J. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Newell, D. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Williams, M. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL)

    2015-08-20

    This report describes the results of testing to quantify the degradation products resulting from the dilution and storage of Antifoam 747. Antifoam degradation is of concern to the Defense Waste Processing Facility (DWPF) due to flammable decomposition products in the vapor phase of the Chemical Process Cell vessels, as well as the collection of flammable and organic species in the offgas condensate. The discovery that hexamethyldisiloxane is formed from the antifoam decomposition was the basis for a Potential Inadequacy in the Safety Analysis declaration by the DWPF.

  5. Chlorophyll Degradation in Horticultural Crops

    OpenAIRE

    Kaewsuksaeng, Samak

    2011-01-01

    One of the symptoms of senescence in harvested horticultural crops is the loss of greenness that comes with the degradation of chlorophyll. With senescence, the chlorophyll-degrading enzyme activities such as chlorophyllase, Mg-dechelatase or Mg-dechelation activity, a new chlorophyll-degrading enzyme, pheophytinase, pheophorbidase and chlorophyll-degrading peroxidase, which are involved in chlorophyll degradation, affected greatly in stored horticultural crops. The chlorophyll derivatives, e...

  6. Aerobic degradation of 4-nitroaniline (4-NA) via novel degradation intermediates by Rhodococcus sp. strain FK48

    International Nuclear Information System (INIS)

    Highlights: • This study reports isolation of a novel bacterium capable of mineralizing 4-nitroaniline (4-NA). • This bacterium has been identified as Rhodococcus sp. strain FK48. • Strain FK48 degrades 4-NA via a novel aerobic degradation pathway that involves 4-AP and 1,2,4-BT. • Subsequent degradation proceeds via ring fission and formation of maleylacetate. • This is the first report showing elucidation of catabolic pathway for microbial degradation 4-NA. -- Abstract: An aerobic strain, Rhodococcus sp. strain FK48, capable of growing on 4-nitroaniline (4-NA) as the sole source of carbon, nitrogen, and energy has been isolated from enrichment cultures originating from contaminated soil samples. During growth studies with non- induced cells of FK48 catalyzed sequential denitrification (release of NO2 substituent) and deamination (release of NH2 substituent) of 4-NA. However, none of the degradation intermediates could be identified with growth studies. During resting cell studies, 4-NA-induced cells of strain FK48 transformed 4-NA via a previously unknown pathway which involved oxidative hydroxylation leading to formation of 4-aminophenol (4-AP). Subsequent degradation involved oxidated deamination of 4-AP and formation of 1,2,4-benzenetriol (BT) as the major identified terminal aromatic intermediate. Identification of these intermediates was ascertained by HPLC, and GC–MS analyses of the culture supernatants. 4-NA-induced cells of strain FK48 showed positive activity for 1,2,4-benzenetriol dioxygenase in spectrophotometric assay. This is the first conclusive study on aerobic microbial degradation of 4-NA and elucidation of corresponding metabolic pathway

  7. The Smad pathway in transforming growth factor-β signaling

    Institute of Scientific and Technical Information of China (English)

    林海燕; 王红梅; 祝诚

    2003-01-01

    The Smad pathway is involved in transforming growth factor-β (TGF-β) signal transduction. The Smad complex binds with the promoter of target gene to modulate gene transcription. Various transcriptional coactivators and corepressors associate directly with Smads for appropriate binding of Smads to target promoters and regulation of Smads transcriptional activities. The ultimate degradation of Smads mediated by the ubiquitin-proteasome pathway (UPP) has been established as a mechanism to shut off the Smad pathway. In addition to the Smad pathway, TGF-β can also activate other signaling pathway such as the MAPK pathway. The cross-talk of the Smad pathway with other signaling pathways constitutes an important mechanism for the regulatory network of TGF-β Signaling.

  8. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    The outputs from the drift degradation analysis support scientific analyses, models, and design calculations, including the following: (1) Abstraction of Drift Seepage; (2) Seismic Consequence Abstraction; (3) Structural Stability of a Drip Shield Under Quasi-Static Pressure; and (4) Drip Shield Structural Response to Rock Fall. This report has been developed in accordance with ''Technical Work Plan for: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The drift degradation analysis includes the development and validation of rockfall models that approximate phenomenon associated with various components of rock mass behavior anticipated within the repository horizon. Two drift degradation rockfall models have been developed: the rockfall model for nonlithophysal rock and the rockfall model for lithophysal rock. These models reflect the two distinct types of tuffaceous rock at Yucca Mountain. The output of this modeling and analysis activity documents the expected drift deterioration for drifts constructed in accordance with the repository layout configuration (BSC 2004 [DIRS 172801])

  9. Radiation degradation of silk

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Kazushige; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Silk fibroin powder was prepared from irradiated silk fibroin fiber by means of only physical treatment. Silk fibroin fiber irradiated with an accelerated electron beam in the dose range of 250 - 1000 kGy was pulverized by using a ball mill. Unirradiated silk fibroin fiber was not pulverized at all. But the more irradiation was increased, the more the conversion efficiency from fiber to powder was increased. The conversion efficiency of silk fibroin fiber irradiated 1000 kGy in oxygen was 94%. Silk fibroin powder shows remarkable solubility, which dissolved 57% into water of ambient temperature. It is a very interesting phenomenon that silk fibroin which did not treat with chemicals gets solubility only being pulverized. In order to study mechanism of solubilization of silk fibroin powder, amino acid component of soluble part of silk fibroin powder was analyzed. The more irradiation dose up, the more glycine or alanine degraded, but degradation fraction reached bounds about 50%. Other amino acids were degraded only 20% even at the maximum. To consider crystal construction of silk fibroin, it is suggested that irradiation on silk fibroin fiber selectively degrades glycine and alanine in amorphous region, which makes it possible to pulverize and to dissolve silk fibroin powder. (author)

  10. Enantioselective Degradation Mechanism of Beta-Cypermethrin in Soil From the Perspective of Functional Genes.

    Science.gov (United States)

    Yang, Zhong-Hua; Ji, Guo-Dong

    2015-12-01

    The behavior and mechanisms of the enantioselective degradation of beta-cypermethrin were studied in soil. The four isomers were degraded at different rates, and the enantiomer fractions of alpha-cypermethrin and theta-cypermethrin exceeded 0.5. Moreover, 3-phenoxybenzoic acid, phenol, and protocatechuic acid were detected; based on the presence of these metabolites, we predicted the degradation pathway and identified the functional genes that are related to this degradation process. We established quantitative relationships between the data on degradation kinetics and functional genes; we found that the quantitative relationships between different enantiomers differed even under the same conditions, and the genes pobA and pytH played key roles in limiting the degradation rate. Data obtained using path analysis revealed that the same gene had different direct and indirect effects on the degradation of different isomers. A mechanism was successfully proposed to explain the selective degradation of chiral compounds based on the perspective of functional genes.

  11. Detection of pump degradation

    Energy Technology Data Exchange (ETDEWEB)

    Greene, R.H.; Casada, D.A.; Ayers, C.W. [and others

    1995-08-01

    This Phase II Nuclear Plant Aging Research study examines the methods of detecting pump degradation that are currently employed in domestic and overseas nuclear facilities. This report evaluates the criteria mandated by required pump testing at U.S. nuclear power plants and compares them to those features characteristic of state-of-the-art diagnostic programs and practices currently implemented by other major industries. Since the working condition of the pump driver is crucial to pump operability, a brief review of new applications of motor diagnostics is provided that highlights recent developments in this technology. The routine collection and analysis of spectral data is superior to all other technologies in its ability to accurately detect numerous types and causes of pump degradation. Existing ASME Code testing criteria do not require the evaluation of pump vibration spectra but instead overall vibration amplitude. The mechanical information discernible from vibration amplitude analysis is limited, and several cases of pump failure were not detected in their early stages by vibration monitoring. Since spectral analysis can provide a wealth of pertinent information concerning the mechanical condition of rotating machinery, its incorporation into ASME testing criteria could merit a relaxation in the monthly-to-quarterly testing schedules that seek to verify and assure pump operability. Pump drivers are not included in the current battery of testing. Operational problems thought to be caused by pump degradation were found to be the result of motor degradation. Recent advances in nonintrusive monitoring techniques have made motor diagnostics a viable technology for assessing motor operability. Motor current/power analysis can detect rotor bar degradation and ascertain ranges of hydraulically unstable operation for a particular pump and motor set. The concept of using motor current or power fluctuations as an indicator of pump hydraulic load stability is presented.

  12. Plant enhanced degradation of phenanthrene in the contaminated soil

    Institute of Scientific and Technical Information of China (English)

    LIAO Min; XIE Xiao-mei

    2006-01-01

    The degradative characteristics ofphenanthrene, microbial biomass carbon, plate counts of heterotrophic bacteria and most probable number (MPN) of phenanthrene degraders in non-rhizosphere or rhizosphere soils with uninoculating or inoculating phenanthrene degraders were measured. At the initial concentration of 20 mg phenanthrene/kg soil, the half-lives of phenanthrene in uninoculated non-rhizosphere soil, uninoculated rhizosphere soil, inoculated non-rhizosphere soil, and inoculated rhizosphere soil were measured to be 81.5, 47.8, 15.1 and 6.4 d, respectively, and corresponding kinetic data fitted first-order kinetics. The highest degradation rate of phenanthrene was observed in inoculated rhizosphere soil. The degradative characteristics of phenanthrene were closely related to the effects of vegetation on soil microbial process. Vegetation could enhance the magnitude ofrhizosphere microbial communities, microbial biomass content, and heterotrophic bacterial community, but barely influence those community components responsible for phenanthrene degradation. Results suggested that combination of vegetation and inoculation with degrading microorganisms of target organic contaminants was a better pathway to enhance degradation of the organic contaminants in soil.

  13. Changes in collagen synthesis and degradation during skeletal muscle growth

    International Nuclear Information System (INIS)

    The changes in collagen metabolism during skeletal muscle growth were investigated by measuring rates of synthesis and degradation during stretch-induced hypertrophy of the anterior latissimus dorsi muscle of the adult chicken (Gallus domesticus). Synthesis rates were obtained from the uptake of tritiated proline injected intravenously with a flooding dose of unlabeled proline. Degradation of newly synthesized and ''mature'' collagen was estimated from the amount of hydroxyproline in the free pool as small molecular weight moieties. In normal muscle, the synthesis rate was 1.1 +/- 0.3%/day, with 49 +/- 7% of the newly produced collagen degraded rapidly after synthesis. During hypertrophy there was an increase of about fivefold in the rate of synthesis (P less than 0.01), a 60% decrease in the rate of degradation of newly synthesized collagen (P less than 0.02), and an increase of about fourfold in the amount of degradation of mature collagen (P less than 0.01). These results suggest an important role for degradative as well as synthetic processes in the regulation of collagen mass. They indicate that enhanced degradation of mature collagen is required for muscle growth and suggest a physiological role for the pathway whereby in normal muscle, a large proportion of newly produced collagen is rapidly degraded

  14. Untargeted metabolic profiling of Vitis vinifera during fungal degradation.

    Science.gov (United States)

    Karpe, Avinash V; Beale, David J; Morrison, Paul D; Harding, Ian H; Palombo, Enzo A

    2015-05-01

    This paper illustrates the application of an untargeted metabolic profiling analysis of winery-derived biomass degraded using four filamentous fungi (Trichoderma harzianum, Aspergillus niger, Penicillium chrysogenum and P. citrinum) and a yeast (Saccharomyces cerevisiae). Analysis of the metabolome resulted in the identification of 233 significant peak features [P 2 and signal-to-noise ratio >50] using gas chromatography-mass spectrometry followed by statistical chemometric analysis. Furthermore, A. niger and P. chrysogenum produced higher biomass degradation due to considerable β-glucosidase and xylanase activities. The major metabolites generated during fungal degradation which differentiated the metabolic profiles of fungi included sugars, sugar acids, organic acids and fatty acids. Although, P. chrysogenum could degrade hemicelluloses due to its high β-glucosidase and xylanase activities, it could not utilize the resultant pentoses, which A. niger and P. citrinum could do efficiently, thus indicating a need of mixed fungal culture to improve the biomass degradation. Saccharomyces cerevisiae, a non-cellulose degrader, exhibited sugar accumulation during the fermentation. Penicillium chrysogenum was observed to degrade about 2% lignin, a property not observed in other fungi. This study emphasized the differential fungal metabolic behavior and demonstrated the potential of metabolomics in optimizing degradation or manipulating pathways to increase yields of products of interest. PMID:25868913

  15. Targeting Notch degradation system provides promise for breast cancer therapeutics.

    Science.gov (United States)

    Liu, Jing; Shen, Jia-Xin; Wen, Xiao-Fen; Guo, Yu-Xian; Zhang, Guo-Jun

    2016-08-01

    Notch receptor signaling pathways play an important role, not only in normal breast development but also in breast cancer development and progression. As a group of ligand-induced proteins, different subtypes of mammalian Notch (Notch1-4) are sensitive to subtle changes in protein levels. Thus, a clear understanding of mechanisms of Notch protein turnover is essential for understanding normal and pathological mechanisms of Notch functions. It has been suggested that there is a close relationship between the carcinogenesis and the dysregulation of Notch degradation. However, this relationship remains mostly undefined in the context of breast cancer, as protein degradation is mediated by numerous signaling pathways as well as certain molecule modulators (activators/inhibitors). In this review, we summarize the published data regarding the regulation of Notch family member degradation in breast cancer, while emphasizing areas that are likely to provide new therapeutic modalities for mechanism-based anti-cancer drugs. PMID:27263934

  16. Metagenomic insights into RDX-degrading potential of the ovine rumen microbiome

    Science.gov (United States)

    The ovine rumen is capable of rapid degradation of nitroaromatic compounds, such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). While ruminal RDX-degrading bacteria have been identified, genes and biological pathways responsible for the biochemical processes in the rumen have yet to be character...

  17. Catabolism of pyrimidines in yeast: A tool to understand degradation of anticancer drugs

    DEFF Research Database (Denmark)

    Andersen, Gorm; Merico, A.; Bjornberg, O.;

    2006-01-01

    The pyrimidine catabolic pathway is of crucial importance in cancer patients because it is involved in degradation of several chemotherapeutic drugs, such as 5-fluorouracil; it also is important in plants, unicellular eukaryotes, and bacteria for the degradation of pyrimidine-based biocides...

  18. Catabolism of pyrimidines in yeast: a tool to understand degradation of anticancer drugs

    DEFF Research Database (Denmark)

    Andersen, G; Merico, A; Björnberg, O;

    2006-01-01

    The pyrimidine catabolic pathway is of crucial importance in cancer patients because it is involved in degradation of several chemotherapeutic drugs, such as 5-fluorouracil; it also is important in plants, unicellular eukaryotes, and bacteria for the degradation of pyrimidine-based biocides...

  19. Semiempirical Predictions of Chemical Degradation Reaction Mechanisms of CL-20 as Related to Molecular Structure

    Energy Technology Data Exchange (ETDEWEB)

    Qasim, Mohammad M.; Furey, John; Fredrickson, Herbert L.; Szecsody, Jim E.; Mcgrath, Chris J.; Bajpai, Rakesh

    2004-10-01

    Quantum mechanical methods and force field molecular mechanics were used to characterize cage cyclic nitramines and to predict environmental degradation mechanisms. Due to structural similarities it is predicted that, under homologous circumstances, the major environmental RDX degradation pathways should also be effective for CL-20 and similar cyclic nitramines.

  20. Auxin-induced degradation dynamics set the pace for lateral root development

    Science.gov (United States)

    Auxin elicits diverse cell behaviors through a simple nuclear signaling pathway initiated by degradation of Aux/IAA co-repressors. Our previous work revealed that members of the large Arabidopsis Aux/IAA family exhibit a range of degradation rates in synthetic contexts. However, it remained an unr...