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Sample records for acid edta ethylene

  1. Role of ethylene diamine tetra-acetic acid (EDTA) in catheter lock solutions: EDTA enhances the antifungal activity of amphotericin B lipid complex against Candida embedded in biofilm.

    PubMed

    Raad, Issam I; Hachem, Ray Y; Hanna, Hend A; Fang, Xiang; Jiang, Ying; Dvorak, Tanya; Sherertz, Robert J; Kontoyiannis, Dimitrios P

    2008-12-01

    Ethylene diamine tetra-acetic acid (EDTA) is an anticoagulant with antibiofilm-enhancing activity. We therefore used an in vitro biofilm model to determine the activity of amphotericin B lipid complex (ABLC) with or without EDTA against Candida embedded in biofilm on silicone disk surfaces. Clinical blood isolates from cancer patients infected with Candida albicans or Candida parapsilosis were used. Silicone disks were colonised with C. albicans or C. parapsilosis and were sequentially incubated in plasma and then in Mueller-Hinton broth containing 10(5) colony-forming units of each organism. All tests were performed in triplicate. The disks were subsequently placed and incubated for 6h and 8h in solutions containing ABLC alone, EDTA alone, ABLC+EDTA or broth (control). Disks were then removed, sonicated and colony counts were determined. ABLC+EDTA (30 mg/mL) was significantly more effective than ABLC, EDTA and control against C. parapsilosis at 6h (P < or = 0.01) and against C. albicans at 8h (P < or = 0.04). In patients with catheter-related candidaemia when catheter removal is not feasible, the combination of ABLC+EDTA may be considered for antifungal catheter lock solution as part of a catheter salvage therapy. PMID:18783924

  2. Growth and spectral characterization of ethylene diamine tetra acetic acid (EDTA) doped zinc sulphate hepta hydrate - a semi organic NLO material.

    PubMed

    Ramachandra Raja, C; Ramamurthi, K; Manimekalai, R

    2012-12-01

    Semi-organic non-linear optical single crystals of ethylene diamine tetra acetic acid (EDTA) doped zinc sulphate hepta hydrate crystals were grown by slow evaporation solution growth technique, at room temperature, using de-ionized water as solvent. The modes of vibrations of different molecular groups present in the grown crystal were identified by FT-IR technique. The optical absorbance/transmittance was recorded in the wavelength range of 190-1100 nm. Thermal properties of the grown crystal were studied by thermo gravimetric analysis and differential thermal analysis. The melting point of the grown crystal was estimated by differential scanning calorimetric analysis. The inclusion of the dopant (EDTA) was confirmed by colorimetric estimation method. The second harmonic generation efficiency is about 30% of potassium dihydrogen orthophosphate.

  3. Enhanced ALP activity of MG63 cells cultured on hydroxyapatite-poly(ethylene glycol) hydrogel composites prepared using EDTA-OH.

    PubMed

    Ito, Temmei; Sasaki, Makoto; Taguchi, Tetsushi

    2015-03-02

    In order to obtain a hydroxyapatite (HAp)-poly(ethylene glycol) (PEG) composite, tetra amine-terminated PEG was crosslinked using disuccinimidyl tartrate to obtain a PEG hydrogel. Using two kinds of chelators with different stability constants for Ca ion (N-(2-hydroxyethyl) ethylenediamine-N,N',N'-triacetic acid (EDTA-OH, 8.14), and ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA, 10.96)), calcium phosphate was deposited within PEG hydrogels by heating the chelator-containing calcium phosphate solution at 90 °C. X-ray diffraction analysis showed that the deposited calcium phosphate was HAp. The crystallinity of the HAp deposited using EDTA-OH was low compared with that obtained using EDTA, but the amount of HAp deposited within the PEG hydrogel using EDTA-OH was higher than that deposited using EDTA. Significantly more human osteoblast-like MG-63 cells adhered on the HAp-PEG composite prepared using EDTA-OH than on the HAp-PEG composites prepared using EDTA. Furthermore, the alkaline phosphatase activity of MG-63 cultured on the HAp-PEG composite prepared using EDTA-OH was four times higher than that on the HAp-PEG composite prepared using EDTA. Therefore, the HAp-PEG composite prepared using EDTA-OH has potential as a bone substitute material.

  4. Biocompatibility of EDTA, EGTA and citric acid.

    PubMed

    Sousa, Simone Maria Galvão de; Bramante, Clovis Monteiro; Taga, Eulázio Mikio

    2005-01-01

    This in vivo study evaluated, through the physicochemical assay method for quantification of enhanced vascular permeability, the irritating potential of EDTA, EGTA, citric acid and saline. Thirty-two male Wister rats were anesthetized and four experimental sites were demarcated on their backs. Injections of 2% Evans blue (20 mg/kg) were administered intravenously into the lateral caudal vein. The test solutions were immediately injected intradermally (0.01 mL) into the experimental sites. The animals were killed 30 min, 1, 3 and 6 h after injection of the solutions and each piece of skin was submerged in formamide and incubated at 45 masculineC for 72 h. After filtration, the optical density was measured in a spectrophotometer and the total amount of dye extracted from the samples was calculated by means of a standard calibration curve. Data were analyzed statistically by two-way ANOVA and Tukey's HSD test. Compared to control, EDTA had the greatest volume of dye followed by EGTA and citric acid, for all time periods. There were statistically significant differences between all solutions (p<0.01). Considering the periods assessed, a significant difference was observed between the 3- and 6-h groups (p<0.05), but not between the 30-min and 1-h groups. Among the organic acids evaluated in this study, citric acid yielded the lowest amount of extracted dye. This indicates that the citric acid was the least irritating solution.

  5. Kinetics of Fe(III)*EDTA reduction by ascorbic acid

    SciTech Connect

    Li, W.; Harkness, J.B.L.; Mendelsohn, M.H.

    1992-01-01

    The kinetics of the reduction of ferric chelate by ascorbic acid have been determined at a typical flue-gas scrubber-system operating temperature ([approximately]55[degrees]C). The ascorbic acid reaction has the same reduction rate expression as the reduction by bisulfite ions, namely, first order with respect to the concentrations of both Fe(III)*EDTA and monoionic species of ascorbic acid. The reaction rate isnegative first order with respect to Fe(II)*EDTA concentration. In the pH range of 6--8, reduction of the hydrolyzed form of the metal chelate compound was negligible. The rate constant for the ascorbic acid reduction reaction is almost 400 times larger than that for the bisulfite reduction reaction under the same reaction conditions. There was no contribution associated with the nonionized form of ascorbic acid.

  6. Kinetics of Fe(III)*EDTA reduction by ascorbic acid

    SciTech Connect

    Li, W.; Harkness, J.B.L.; Mendelsohn, M.H.

    1992-12-01

    The kinetics of the reduction of ferric chelate by ascorbic acid have been determined at a typical flue-gas scrubber-system operating temperature ({approximately}55{degrees}C). The ascorbic acid reaction has the same reduction rate expression as the reduction by bisulfite ions, namely, first order with respect to the concentrations of both Fe(III)*EDTA and monoionic species of ascorbic acid. The reaction rate isnegative first order with respect to Fe(II)*EDTA concentration. In the pH range of 6--8, reduction of the hydrolyzed form of the metal chelate compound was negligible. The rate constant for the ascorbic acid reduction reaction is almost 400 times larger than that for the bisulfite reduction reaction under the same reaction conditions. There was no contribution associated with the nonionized form of ascorbic acid.

  7. Direct analysis of ethylenediaminetetraacetic acid (EDTA) on concrete by reactive-desorption electrospray ionization mass spectrometry.

    PubMed

    Lebeau, D; Reiller, P E; Lamouroux, C

    2015-01-01

    Analysis of organic ligands such as ethylenediaminetetraacetic acid (EDTA) is today an important challenge due to their ability to increase the mobility of radionuclides and metals. Reactive desorption electrospray ionization mass spectrometry (reactive-DESI-MS) was used for direct analysis of EDTA on concrete samples. EDTA forms complexes and those with Fe(III) ions are among the most thermodynamically favored. This complexing capacity was used to improve the specific detection of EDTA directly on a concrete matrix by doping the solvent spray of DESI with a solution of FeCl3 to selectively create the complex between EDTA and Fe(III). Thus, EDTA sensitivity was largely improved by two orders of magnitude with reactive-DESI-MS experiments thanks to the specific detection of EDTA as a [EDTA-4H+Fe(III)](-) complex. The proof of principle that reactive DESI can be applied to concrete samples to detect EDTA has been demonstrated. Its capacity for semi-quantitative determination and localization of EDTA under ambient conditions and with very little sample preparation, minimizing sample manipulations and solvent volumes, two important conditions for the development of new methodologies in the field of analytical chemistry, has been shown.

  8. [Cd uptake in rice cultivars and Cd fractions in soil treated with organic acids and EDTA].

    PubMed

    Zhang, Hai-Bo; Li, Yang-Rui; Xu, Wei-Hong; Chen, Gui-Qing; Wang, Hui-Xian; Han, Gui-Qi; Zhang, Xiao-Jing; Xiong, Zhi-Ting; Zhang, Jin-Zhong; Xie, De-Ti

    2011-09-01

    A pot experiment was conducted to examine the yield, quality and cadmium (Cd) uptake in different rice cultivars, and Cd speciation in soil after exposing to Cd (0, 1 and 5 mg x kg(-1)) in the presence of organic acids and ethylenediamine tetraacetic acid (EDTA). The results showed that general increase in the yield for cultivars Xiushui63 and II you527 was observed. Yield of two rice cultivars were in order of organic acids treatment or organic acids + 1/2EDTA treatment > EDTA treatment. The exchangeable, carbonate related and ferric-manganese oxidation related Cd increased; while organic complexation Cd and residules decreased in the presence of organic acids and EDTA. Cadmium concentrations in grain, straw and roots of both cultivars markedly reduced in the presence of organic acids and EDTA. Grain Cd concentration was the lowest for plants treated with EDTA, followed by organic acids + 1/2EDTA, and the highest Cd concentration in grain was found in the treatment with organic acids. Grain Cd concentration decreased by 9.0% to 49.3% and 16.5% to 30.6% at 1 mg x kg(-1) Cd in the presence of organic acids and EDTA, and by 12.7% to 28.5% and 4.3% to 19.1% at 5 mg x kg(-1) Cd. Cadmium concentration and accumulation in plants and total Cd content in soil were higher in Xiushui63 than in that in II you527. Grain Cd concentration decreased, and yield and quality of two rice cultivars increased at the same time in the presence of organic acids + 1/2EDTA.

  9. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid... for use in contact with food subject to the provisions of this section. (a) The ethylene-acrylic...

  10. Influence of ethylenediaminetetraacetic acid (EDTA) on the structural stability of endoglucanase from Aspergillus aculeatus.

    PubMed

    Naika, Gajendra S; Tiku, Purnima Kaul

    2011-07-13

    The effect of the chelating agent ethylenediaminetetraacetic acid (EDTA) on the structure and function of endoglucanase is studied. In the presence of 2 mM EDTA, endoglucanase showed an enhanced enzymatic activity of 1.5-fold compared to control. No further change in activity was observed with increase in the concentration of EDTA to 5 mM. The K(m) values for control and in the presence of EDTA are 0.060 and 0.044%, respectively, and K(cat) was 1.9 min(-1) in the presence of EDTA. The kinetic parameters indicated a decrease in the K(m) with an increase in the K(cat). Far-ultraviolet circular dichroism (far-UV-CD) results showed a 20% decrease in ellipticity values at 217 nm in the presence of EDTA compared to native enzyme. The apparent T(m) shifted from a control value of 57 ± 1 to 76 ± 1 °C in the presence of EDTA (5 mM). The above results suggested that the enhanced activity in the presence of EDTA is due to an increase in the K(cat) and flexible conformation of the enzyme. The stability of endoglucanase increased in the presence of EDTA.

  11. Evaluating EDTA as a substitute for phosphoric acid-etching of enamel and dentin.

    PubMed

    Imbery, Terence A; Kennedy, Matthew; Janus, Charles; Moon, Peter C

    2012-01-01

    Matrix metalloproteinases (MMPs) are proteolytic enzymes released when dentin is acid-etched. The enzymes are capable of destroying unprotected collagen fibrils that are not encapsulated by the dentin adhesive. Chlorhexidine applied after etching inhibits the activation of released MMPs, whereas neutral ethylenediamine tetra-acetic acid (EDTA) prevents the release of MMPs. The purpose of this study was to determine if conditioning enamel and dentin with EDTA can be a substitute for treating acid-etching enamel and dentin with chlorhexidine. A column of composite resin was bonded to enamel and dentin after conditioning. Shear bond strengths were evaluated after 48 hours and after accelerated aging for three hours in 12% sodium hypochlorite. Shear bond strengths ranged from 15.6 MP a for accelerated aged EDTA enamel specimens to 26.8 MPa for dentin conditioned with EDTA and tested after 48 hours. A three-way ANOVA and a Tukey HSD test found statistically significant differences among the eight groups and the three independent variables (P < 0.05). EDTA was successfully substituted for phosphoric acid-etched enamel and dentin treated with chlorhexidine. Interactions of conditioning agent and aging were significant for dentin but not for enamel. In an effort to reduce the detrimental effects of MMPs, conditioning enamel and dentin with EDTA is an alternative to treating acid-etched dentin and enamel with chlorhexidine.

  12. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  13. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  14. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  15. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  16. Simulation of the influence of EDTA on the sorption of heavy metals by humic acids

    NASA Astrophysics Data System (ADS)

    Kropacheva, T. N.; Didik, M. V.; Kornev, V. I.

    2015-04-01

    The results of mathematical simulation of sorption equilibria with the participation of divalent cations of heavy metals (HMs), chelant (EDTA), and insoluble forms of humic acids (HAs) are discussed. It is shown that the formation of chelates of metals with EDTA in solutions results in the decreasing sorption of the metals by humic acids. We also analyzed the effect of the acidity of the medium and the HM: EDTA: HA ratio (in a wide range) on the desorption of metals. The desorbing effect of EDTA on the metals is the highest at pH 3-5 and increases with an increase in the concentration of EDTA and a decrease in the concentration of HAs. With respect to the remobilization of metals under the impact of EDTA, the metal cations can be arranged into the following sequence: Cu(II) > Ni(II) > Pb(II) ≫ Cd(II) > Co(II) > Zn(II). The obtained data have been used to analyze the remobilization / extraction of HMs from soils with a high content of humic substances.

  17. EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta).

    PubMed

    Sinhal, V K; Srivastava, Alok; Singh, V P

    2010-05-01

    Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.

  18. Optimizing anti-coking abilities of zeolites by ethylene diamine tetraacetie acid modification on catalytic fast pyrolysis of corn stalk

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Zhong, Zhaoping; Song, Zuwei; Ding, Kuan; Chen, Paul; Ruan, Roger

    2015-12-01

    In order to minimize coke yield during biomass catalytic fast pyrolysis (CFP) process, ethylene diamine tetraacetie acid (EDTA) chemical modification method is carried out to selectively remove the external framework aluminum of HZSM-5 catalyst. X-ray diffraction (XRD), nitrogen (N2)-adsorption and ammonia-temperature programmed desorption (NH3-TPD) techniques are employed to investigate the porosity and acidity characteristics of original and modified HZSM-5 samples. Py-GC/MS and thermo-gravimetric analyzer (TGA) experiments are further conducted to explore the catalytic effect of modified HZSM-5 samples on biomass CFP and to verify the positive effect on coke reduction. Results show that EDTA treatment does not damage the crystal structure of HZSM-5 zeolites, but leads to a slight increase of pore volume and pore size. Meanwhile, the elimination of the strong acid peak indicates the dealumination of outer surface of HZSM-5 zeolites. Treatment time of 2 h (labeled EDTA-2H) is optimal for acid removal and hydrocarbon formation. Among all modified catalysts, EDTA-2H performs the best for deacidification and can obviously increase the yields of positive chemical compositions in pyrolysis products. Besides, EDTA modification can improve the anti-coking properties of HZSM-5 zeolites, and EDTA-2H gives rise to the lowest coke yield.

  19. Controlling of dielectrical properties of hydroxyapatite by ethylenediamine tetraacetic acid (EDTA) for bone healing applications.

    PubMed

    Kaygili, Omer; Ates, Tankut; Keser, Serhat; Al-Ghamdi, Ahmed A; Yakuphanoglu, Fahrettin

    2014-08-14

    The hydroxyapatite (HAp) samples in the presence of various amounts of ethylenediamine tetraacetic acid (EDTA) were prepared by sol-gel method. The effects of EDTA on the crystallinity, phase structure, chemical, micro-structural and dielectric properties of HAp samples were investigated. With the addition of EDTA, the average crystallite size of the HAp samples is gradually decreased from 30 to 22 nm and the crystallinity is in the range of 65-71%. The values of the lattice parameters (a and c) and volume of the unit cell are decreased by stages with the addition of EDTA. The dielectric parameters such as relative permittivity, dielectric loss and relaxation time are affected by the adding of EDTA. The alternating current conductivity of the as-synthesized hydroxyapatites increases with the increasing frequency and obeys the universal power law behavior. The HAp samples exhibit a non-Debye relaxation mechanism. The obtained results that the dielectrical parameters of the HAp sample can be controlled by EDTA. PMID:24747847

  20. Controlling of dielectrical properties of hydroxyapatite by ethylenediamine tetraacetic acid (EDTA) for bone healing applications.

    PubMed

    Kaygili, Omer; Ates, Tankut; Keser, Serhat; Al-Ghamdi, Ahmed A; Yakuphanoglu, Fahrettin

    2014-08-14

    The hydroxyapatite (HAp) samples in the presence of various amounts of ethylenediamine tetraacetic acid (EDTA) were prepared by sol-gel method. The effects of EDTA on the crystallinity, phase structure, chemical, micro-structural and dielectric properties of HAp samples were investigated. With the addition of EDTA, the average crystallite size of the HAp samples is gradually decreased from 30 to 22 nm and the crystallinity is in the range of 65-71%. The values of the lattice parameters (a and c) and volume of the unit cell are decreased by stages with the addition of EDTA. The dielectric parameters such as relative permittivity, dielectric loss and relaxation time are affected by the adding of EDTA. The alternating current conductivity of the as-synthesized hydroxyapatites increases with the increasing frequency and obeys the universal power law behavior. The HAp samples exhibit a non-Debye relaxation mechanism. The obtained results that the dielectrical parameters of the HAp sample can be controlled by EDTA.

  1. Nucleation of calcium carbonate in presence of citric acid, DTPA, EDTA and pyromellitic acid.

    PubMed

    Westin, K-J; Rasmuson, A C

    2005-02-15

    The influence of four calcium complexing additives, i.e., citric acid (CIT), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) and pyromellitic acid (PMA), and their concentration on the induction time of calcium carbonate nucleation has been studied. The experiments were performed by rapidly mixing a sodium carbonate solution and a calcium chloride solution of various concentrations. The induction time was obtained by recording the white light absorption of the solution. Chemical speciation was used to estimate the initial thermodynamic driving force of each experiment. The induction time was found to increase with additive concentration. The effect varies from one additive to another. CIT causes the greatest increase in induction time and PMA the least. Using classical nucleation theory the experimental data were evaluated in terms of the interfacial energy. In pure water a value of 37.8 mJ m(-2) was obtained, showing good agreement with other works. CIT, DTPA and EDTA caused a notable increase of the interfacial energy at a concentration of 0.5 mmol l(-1). PMA does not appear to have any effect at all on the interfacial energy. Different mechanisms for the influence of the additives on the measured induction time and on the estimated interfacial energy are discussed. PMID:15589542

  2. Safety assessment of iron EDTA [sodium iron (Fe(3+)) ethylenediaminetetraacetic acid]: summary of toxicological, fortification and exposure data.

    PubMed

    Heimbach, J; Rieth, S; Mohamedshah, F; Slesinski, R; Samuel-Fernando, P; Sheehan, T; Dickmann, R; Borzelleca, J

    2000-01-01

    Iron EDTA [sodium iron (Fe(3+)) ethylenediaminetetraacetic acid (EDTA)], shown to have a significant beneficial effect on iron status by increasing iron bioavailability in human diets, has been proposed for use as a fortificant in certain grain-based products including breakfast cereals and cereal bars. This paper presents an assessment of the safety of iron EDTA for its intended uses in these products. Iron EDTA, like other EDTA-metal complexes, dissociates in the gastrointestinal tract to form iron, which is bioavailable, and an EDTA salt; absorption of the metal ion and EDTA are independent. Because of this dissociation, consideration of information on EDTA compounds other than iron EDTA is relevant to this safety assessment. EDTA compounds are poorly absorbed in the gastrointestinal tract and do not undergo significant metabolic conversion. They have a low degree of acute oral toxicity. EDTA compounds are not reproductive or developmental toxicants when fed with a nutrient-sufficient diet or minimal diets supplemented with zinc. In chronic toxicity studies, diets containing as much as 5% EDTA were without adverse effects. EDTA compounds were not carcinogenic in experimental animal bioassays and are not directly genotoxic. This lack of significant toxicity is consistent with a history of safe use of other EDTA compounds (CaNa(2)EDTA and Na(2)EDTA) approved by the FDA for use as direct food additives. An upper-bound estimated daily intake (EDI) of EDTA from iron EDTA (1.15mg/kg bw/day for the US population) is less than half the acceptable daily intake (ADI) for EDTA of 2. 5mg/kg bw/day established by JECFA. The data collected and published over the past 20 to 30 years demonstrate that iron EDTA is safe and effective for iron fortification of food products and meets the standard of "reasonable certainty of no harm". Based on the published record, iron EDTA may be regarded as generally recognized as safe (GRAS) for the intended food uses and maximum use levels

  3. Citric acid and ethylene diamine tetra-acetic acid as effective washing agents to treat sewage sludge for agricultural reuse.

    PubMed

    Ren, Xianghao; Yan, Rui; Wang, Hong-Cheng; Kou, Ying-Ying; Chae, Kyu-Jung; Kim, In S; Park, Yong-Jin; Wang, Ai-Jie

    2015-12-01

    This paper presents the effects of different concentrations of citric acid (CA) and ethylene diamine tetra-acetic acid (EDTA) when used as additive reagents for the treatment of sewage sludge for agricultural use. Herein, both the retention of nutrients and removal of metals from the sewage sludge are examined. The average removal rate for the metals after treatment by CA decreased in the order Cu>Pb>Cd>Cr>Zn, while the rates after treatment by EDTA decreased in the order of Pb>Cu>Cr>Cd>Zn. After treatment with CA and EDTA, total nitrogen and total phosphorus concentrations in the sludge decreased, while the content of available nitrogen and Olsen-P increased. In addition, a multi-criteria analysis model-fuzzy analytic network process method (with 3 main factors and 12 assessment sub-factors) was adopted to evaluate the effectiveness of different treatment methods. The results showed that the optimal CA and EDTA concentrations for sewage sludge treatment were 0.60 and 0.125 mol/L, respectively.

  4. Citric acid and ethylene diamine tetra-acetic acid as effective washing agents to treat sewage sludge for agricultural reuse.

    PubMed

    Ren, Xianghao; Yan, Rui; Wang, Hong-Cheng; Kou, Ying-Ying; Chae, Kyu-Jung; Kim, In S; Park, Yong-Jin; Wang, Ai-Jie

    2015-12-01

    This paper presents the effects of different concentrations of citric acid (CA) and ethylene diamine tetra-acetic acid (EDTA) when used as additive reagents for the treatment of sewage sludge for agricultural use. Herein, both the retention of nutrients and removal of metals from the sewage sludge are examined. The average removal rate for the metals after treatment by CA decreased in the order Cu>Pb>Cd>Cr>Zn, while the rates after treatment by EDTA decreased in the order of Pb>Cu>Cr>Cd>Zn. After treatment with CA and EDTA, total nitrogen and total phosphorus concentrations in the sludge decreased, while the content of available nitrogen and Olsen-P increased. In addition, a multi-criteria analysis model-fuzzy analytic network process method (with 3 main factors and 12 assessment sub-factors) was adopted to evaluate the effectiveness of different treatment methods. The results showed that the optimal CA and EDTA concentrations for sewage sludge treatment were 0.60 and 0.125 mol/L, respectively. PMID:26235448

  5. [Evaluation of compounding EDTA and citric acid on remediation of heavy metals contaminated soil].

    PubMed

    Yin, Xue; Chen, Jia-Jun; Cai, Wen-Min

    2014-08-01

    As commonly used eluents, Na2EDTA (EDTA) and citric acid (CA) have been widely applied in remediation of soil contaminated by heavy metals. In order to evaluate the removal of arsenic, cadmium, copper, and lead in the contaminated soil collected in a chemical plant by compounding EDTA and CA, a series of stirring experiments were conducted. Furthermore, the changes in speciation distribution of heavy metals before and after washing were studied. The results showed that, adopting the optimal molar ratio of EDTA/CA (1:1), when the pH of the solution was 3, the stirring time was 30 min, the stirring rate was 150 r x min(-1) and the L/S was 5:1, the removal rates of arsenic, cadmium, copper and lead could reach 11.72%, 43.39%, 24.36% and 27.17%, respectively. And it was found that after washing, for arsenic and copper, the content of acid dissolved fraction rose which increased the percentage of available contents. Fe-Mn oxide fraction mainly contributed to the removal of copper. As for cadmium, the percentages of acid dissolved fraction, Fe-Mn oxide fraction and organic fraction also decreased. In practical projects, speciation changes would pose certain environmental risk after soil washing, which should be taken into consideration.

  6. Simultaneous determination of EDTA, sorbic acid, and diclofenac sodium in pharmaceutical preparations using high-performance liquid chromatography.

    PubMed

    Heydari, Rouhollah; Shamsipur, Mojtaba; Naleini, Nasim

    2013-06-01

    A simple high-performance liquid chromatographic method for simultaneous determination of ethylenediaminetetraacetic acid (EDTA), sorbic acid, and diclofenac sodium was developed and validated. Separation was achieved on a C(18) column (10 cm×4.6 mm) using gradient elution. The mobile phase consisted of acetonitrile-ammonium dihydrogen phosphate buffer solution (0.01 M, pH=2.5, containing 0.8% tetra-n-butyl ammonium hydroxide). The detector wavelength was set at 254 nm. Under these conditions, separation of three compounds was achieved in less than 10 min. The effect of two metal salts and metal concentration on peak area of EDTA was investigated. The pH effect on retention of EDTA and sorbic acid was studied. The method showed linearity for EDTA, sorbic acid, and diclofenac in the ranges of 2.5-100.0, 5.0-200.0, and 20.0-120.0 μg/mL, respectively. The within- and between-day relative standard deviations ranged from 0.52 to 1.94%, 0.50 to 1.34%, and 0.78 to 1.67% for EDTA, sorbic acid, and diclofenac, respectively. The recovery of EDTA, sorbic acid, and diclofenac from pharmaceutical preparation ranged from 96.0-102.0%, 99.7-101.5%, to 97.0-102.5%, respectively. To the best of our knowledge, this is the first report about simultaneous determination of EDTA, sorbic acid, and diclofenac.

  7. Influence of ethylenediaminetetraacetic acid (EDTA) on the on the ability of fatty acids to inhibit the growth of bacteria associated with poultry processing.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of ethylenediaminetetraacetic acid (EDTA) on the bactericidal activity of alkaline salts of fatty acids was examined. A 0.5 M concentration of caproic, caprylic, capric, and lauric acids was dissolved in 1.0 M potassium hydroxide (KOH), and then supplemented with 0, 5, or 10 mM of EDTA. T...

  8. Ferrous iron oxidation by molecular oxygen under acidic conditions: The effect of citrate, EDTA and fulvic acid

    NASA Astrophysics Data System (ADS)

    Jones, Adele M.; Griffin, Philippa J.; Waite, T. David

    2015-07-01

    In this study, the rates of Fe(II) oxidation by molecular oxygen in the presence of citrate, ethylenediaminetetraacetic acid (EDTA) and Suwannee River fulvic acid (SRFA) were determined over the pH range 4.0-5.5 and, for all of the ligands investigated, found to be substantially faster than oxidation rates in the absence of any ligand. EDTA was found to be particularly effective in enhancing the rate of Fe(II) oxidation when sufficient EDTA was available to complex all Fe(II) present in solution, with a kinetic model of the process found to adequately describe all results obtained. When Fe(II) was only partially complexed by EDTA, reactions with reactive oxygen species (ROS) and heterogeneous Fe(II) oxidation were found to contribute significantly to the removal rate of iron from solution at different stages of oxidation. This was possible due to the rapid rate at which EDTA enhanced Fe(II) oxidation and formed ROS and Fe(III). The rapid rate of Fe(III) generation facilitated the formation of free ferric ion activities in excess of those required for ferric oxyhydroxide precipitation following Fe(III)-EDTA dissociation. In comparison, the rate of Fe(II) oxidation was slower in the presence of citrate, and therefore the concentrations of free Fe(III) able to form in the initial stages of Fe(II) oxidation were much lower than those formed in the presence of EDTA, despite the resultant Fe(III)-citrate complex being less stable than that of Fe(III)-EDTA. The slower rate of citrate enhanced oxidation also resulted in slower rates of ROS generation, and, as such, oxidation of the remaining inorganic Fe(II) species by ROS was negligible. Overall, this study demonstrates that organic ligands may substantially enhance the rate of Fe(II) oxidation. Even under circumstances where the ligand is not present at sufficient concentrations to complex all of the Fe(II) in solution, ensuing oxidative processes may sustain an enhanced rate of Fe(II) oxidation relative to that of

  9. Comparison of EDTA- and citric acid-enhanced phytoextraction of heavy metals in artificially metal contaminated soil by Typha angustifolia.

    PubMed

    Muhammad, Dawood; Chen, Fei; Zhao, Jing; Zhang, Guoping; Wu, Feibo

    2009-08-01

    A pot experiment was conducted to study the performance of EDTA and citric acid (CA) addition in improving phytoextraction of Cd, Cu, Pb, and Cr from artificially contaminated soil by T. angustifolia. T. angustifolia showed the remarkable resistance to heavy metal toxicity with no visual toxic symptom including chlorosis and necrosis when exposed to metal stress. EDTA-addition significantly reduced plant height and biomass, compared with the control, and stunted plant growth, while 2.5 and 5 mM CA addition induced significant increases in root dry weight. EDTA, and 5 and 10 mM CA significantly increased shoot Cd, Pb, and Cr concentrations compared with the control, with EDTA being more effective. At final harvest, the highest shoot Cd, Cr, and Pb concentrations were recorded in the treatment of 5 mM EDTA addition, while maximal root Pb concentration was found at the 2.5 mM CA treatment. However, shoot Cd accumulation in the 10 mM CA treatment was 36.9% higher than that in 2.5 mM EDTA, and similar with that in 10 mM EDTA. Shoot Pb accumulation was lower in 10 mM CA than that in EDTA treatments. Further, root Cd, Cu, and Pb accumulation of CA treatments and shoot Cr accumulation in 5 or 10 mM CA treatments were markedly higher than that of control and EDTA treatments. The results also showed that EDTA dramatically increased the dissolution of Cu, Cr, Pb, and Cd in soil, while CA addition had less effect on water-soluble Cu, Cr, and Cd, and no effect on Pb levels. It is suggested that CA can be a good chelator candidate for T. angustifolia used for environmentally safe phytoextraction of Cd and Cr in soils.

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

    PubMed

    Olaimat, Amin N; Holley, Richard A

    2014-04-01

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

  11. Abscisic acid inhibits root growth in Arabidopsis through ethylene biosynthesis.

    PubMed

    Luo, Xingju; Chen, Zhizhong; Gao, Junping; Gong, Zhizhong

    2014-07-01

    When first discovered in 1963, abscisic acid (ABA) was called abscisin II because it promotes abscission. Later, researchers found that ABA accelerates abscission via ethylene. In Arabidopsis, previous studies have shown that high concentrations of ABA inhibit root growth through ethylene signaling but not ethylene production. In the present study in Arabidopsis, we found that ABA inhibits root growth by promoting ethylene biosynthesis. The ethylene biosynthesis inhibitor L-α-(2-aminoethoxyvinyl)-glycine reduces ABA inhibition of root growth, and multiple mutants of ACS (1-aminocyclopropane-1-carboxylate synthase) are more resistant to ABA in terms of root growth than the wild-type is. Two ABA-activated calcium-dependent protein kinases, CPK4 and CPK11, phosphorylate the C-terminus of ACS6 and increase the stability of ACS6 in ethylene biosynthesis. Plants expressing an ACS6 mutant that mimics the phosphorylated form of ACS6 produce more ethylene than the wild-type. Our results reveal an important mechanism by which ABA promotes ethylene production. This mechanism may be highly conserved among higher plants.

  12. Apical microleakage of different root canal sealers after use of maleic acid and EDTA as final irrigants.

    PubMed

    Ulusoy, Ozgür Ilke; Nayir, Yelda; Celik, Kezban; Yaman, Sis Darendeliler

    2014-01-01

    This study aimed to compare the effects of ethylenediaminetetraacetic acid (EDTA) and maleic acid (MA) on the sealing ability of various root canal sealers. Eighty root canals were instrumented and irrigated with either EDTA or MA. They were divided into eight experimental groups and obturated as follows: Group 1: MA + Hybrid Root SEAL/gutta-percha. Group 2: EDTA + Hybrid Root SEAL/gutta-percha. Group 3: MA + iRoot SP/gutta-percha. Group 4: EDTA + iRoot SP/gutta-percha. Group 5: MA + EndoREZ/EndoREZ points. Group 6: EDTA + EndoREZ/EndoREZ points. Group 7: MA + AH Plus/gutta-percha. Group 8: EDTA + AH Plus/gutta-percha. Another ten roots were used as negative and positive controls. The microleakage of each sample was measured at 2-min intervals for 8 min using the fluid filtration method. Data were statistically analyzed with one-way ANOVA, post-hoc Tukey, and paired-samples t tests. The minimum microleakage values were obtained from the teeth obturated with AH Plus and EndoREZ selaers (p < 0.001). The samples with Hybrid Root SEAL showed the maximum leakage (p < 0.001). There were significant differences between the groups irrigated with MA or EDTA in terms of microleakage (p < 0.05). Use of MA resulted in higher microleakage values compared with those using EDTA. The type of final irrigation solution seems to influence the postobturation apical seal. Use of AH Plus and EndoREZ sealers showed better sealing ability compared with IRoot SP and Hybrid Root SEAL.

  13. Efficacy of different final irrigant activation protocols on smear layer removal by EDTA and citric acid.

    PubMed

    Herrera, Daniel R; Santos, Zarina T; Tay, Lidia Y; Silva, Emmanuel J; Loguercio, Alessandro D; Gomes, Brenda P F A

    2013-04-01

    The aim of this study was to evaluate the influence of different activation protocols for chelating agents used after chemo-mechanical preparation (CMP), for smear layer (SL) removal. Forty-five single-rooted human premolars with straight canals and fully formed apex were selected. The specimens were randomly divided into three groups depending on the chelating agent used for smear layer removal: distilled water (DW, control group); 17% ethylenediaminetetraacetic acid (EDTA); and 10% citric acid (CA). Each group was further divided into three subgroups according to the activation protocol used: no-activation (NA), manual dynamic activation (MDA), or sonic activation (SA). After CMP, all specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy (SEM). Two calibrated evaluators attributed scores to each specimen. The differences between activation protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. When chelating agents were activated, either by MDA or SA, it was obtained the best cleaning results with no significant difference between EDTA and CA (P > 0.05). Sonic activation showed the best results when root canal thirds were analyzed, in comparison to MDA and NA groups (P < 0.05). The activation of chelating agents, independent of the protocol used, benefits smear layer removal from root canals.

  14. Cytotoxic effects of 10% citric acid and EDTA-T used as root canal irrigants: an in vitro analysis.

    PubMed

    Sceiza, M F; Daniel, R L; Santos, E M; Jaeger, M M

    2001-12-01

    EDTA-T and 10% citric acid used as root canal irrigants lead to more visible dentinal tubules than 5% sodium hypochlorite associated with 3% hydrogen peroxide. However, these cleansing agents must be compatible with apical periodontal tissue. We analyzed the cytotoxicity of 10% citric acid and EDTA-T in cultured fibroblasts using Trypan blue. The solutions were diluted to 1%, 0.1%, and 0.01% and applied to NIH 3T3 cell cultures. Cells grown on fresh DMEM served as a control. After 0, 6, 12, and 24 h (short-term assay, viability) and 1, 3, 5, and 7 days (long-term assay, survival), the cells were counted using a hemocytometer. In short-term tests, cell viability ranged from 85% to 99% for all experimental groups with no statistical differences when compared with control cultures, except for the group treated with 1% EDTA-T, which caused a progressive decrease in cell viability. In long-term tests, all cultures increased in number from day 1 to the end of the experimental period, showing no inhibition of cell proliferation, except for the cultures treated with 1% EDTA-T, which totally prevented cell growth. All dilutions of 10% citric acid were more biocompatible than EDTA-T. Cultures treated with citric acid had a higher percentage of viable cells in the short-term assays, and the cells retained their self-renewal capacity.

  15. Effects of simulated acid rain, EDTA, or their combination, on migration and chemical fraction distribution of extraneous metals in Ferrosol.

    PubMed

    Wen, Fang; Hou, Hong; Yao, Na; Yan, Zengguang; Bai, Liping; Li, Fasheng

    2013-01-01

    A laboratory repacked soil-leaching column experiment was conducted to study the effects of simulated acid rain or EDTA by themselves or in combination, on migration and chemical speciation distribution of Pb and its alternative rare metals including Ag, Bi, In, Sb, and Sn. Experimental results demonstrate that leaching with simulated acid rain promoted the migration of Bi, In and Pb, and their migration reached down to 8 cm in the soil profile, no enhancement of Sb, Ag or Sn migration was observed. Addition of EDTA significantly enhanced the migration of all six metals, especially Bi, In and Pb. The migration of metals was in the order Pb>Bi>In>Sb>Sn>Ag. The individual and combined effects of acid rain and EDTA increased the environmental risk of metals, by increasing the soluble content of metals in soil solutions and the relative distribution of the exchangeable fraction. Leaching risks of Bi, In and Pb were higher than other three metals.

  16. Radiation effects on the dissolution kinetics of magnetite and hematite in EDTA- and NTA-based dilute chemical decontamination formulations

    NASA Astrophysics Data System (ADS)

    Keny, S. J.; Kumbhar, A. G.; Venkateswaran, G.; Kishore, Kamal

    2005-03-01

    Ethylene diamine tetraacetic acid (EDTA)- and nitrilo triacetic acid (NTA)-based formulations such as citric acid (CA)/EDTA/ascorbic acid (AA), CA/EDTA/gallic acid (GA), CA/NTA/AA and CA/NTA/GA were used for dissolving magnetite and hematite under similar experimental conditions of temperature, amount of the oxide and the concentration of the formulations (close to stoichiometric conditions). In unirradiated solutions, EDTA-based formulations were more efficient in dissolving these oxides than NTA-based formulations. Similarly, formulations containing AA as reductant gave better results as compared to formulations containing GA as reductant in unirradiated solutions. However, in gamma-irradiated formulations, the efficiency of dissolution was affected to a much greater extent in EDTA and AA containing formulations as compared to NTA and GA containing formulations. Both NTA and GA were found to be less prone to radiation degradation as compared to EDTA and AA.

  17. Effect of EDTA and citric acid on phytoremediation of Cr- B[a]P-co-contaminated soil.

    PubMed

    Chigbo, Chibuike; Batty, Lesley

    2013-12-01

    Polycyclic aromatic hydrocarbons and heavy metals in the environment are a concern, and their removal to acceptable level is required. Phytoremediation, the use of plants to treat contaminated soils, could be an interesting alternative to conventional remediation processes. This work evaluates the role of single and combined applications of chelates to single or mixed Cr + benzo[a]pyrene (B[a]P)-contaminated soil. Medicago sativa was grown in contaminated soil and was amended with 0.3 g citric acid, 0.146 g ethylenediaminetetraacetic acid (EDTA), or their combination for 60 days. The result shows that in Cr-contaminated soil, the application of EDTA + citric acid significantly (p<0.05) decreased the shoot dry matter of M. sativa by 55 % and, as such, decreased the Cr removal potential from the soil. The soluble Cr concentration in single Cr or Cr + B[a]P-contaminated soil was enhanced with the amendment of all chelates; however, only the application of citric acid in Cr-contaminated soil (44 %) or EDTA and EDTA + citric acid in co-contaminated soil increased the removal of Cr from the soil (34 and 54 %, respectively). The dissipation of B[a]P in single B[a]P-contaminated soil was effective even without planting and amendment with chelates, while in co-contaminated soil, it was related to the application of either EDTA or EDTA + citric acid. This suggests that M. sativa with the help of chelates in single or co-contaminated soil can be effective in phytoextraction of Cr and promoting the biodegradation of B[a]P.

  18. Resin–dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding

    PubMed Central

    Sauro, Salvatore; Toledano, Manuel; Aguilera, Fatima Sánchez; Mannocci, Francesco; Pashley, David H.; Tay, Franklin R.; Watson, Timothy F.; Osorio, Raquel

    2013-01-01

    Objective To compare resin–dentin bond strengths and the micropermeability of hydrophobic vs. hydrophilic resins bonded to acid-etched or EDTA-treated dentin, using the ethanol wet-bonding technique. Methods Flat dentin surfaces from extracted human third molars were conditioned before bonding with: 37% H3PO4 (15 s) or 0.1 M EDTA (60 s). Five experimental resin blends of different hydrophilicities and one commercial adhesive (SBMP: Scotchbond Multi-Purpose) were applied to ethanol wet-dentin (1 min) and light-cured (20 s). The solvated resins were used as primers (50% ethanol/50% comonomers) and their respective neat resins were used as the adhesive. The resin-bonded teeth were stored in distilled water (24 h) and sectioned in beams for microtensile bond strength testing. Modes of failure were examined by stereoscopic light microscopy and SEM. Confocal tandem scanning microscopy (TSM) interfacial characterization and micropermeability were also performed after filling the pulp chamber with 1 wt% aqueous rhodamine-B. Results The most hydrophobic resin 1 gave the lowest bond strength values to acid-etched dentin and all beams failed prematurely when the resin was applied to EDTA-treated dentin. Resins 2 and 3 gave intermediate bond strengths to both conditioned substrates. Resin 4, an acidic hydrophilic resin, gave the highest bond strengths to both EDTA-treated and acid-etched dentin. Resin 5 was the only hydrophilic resin showing poor resin infiltration when applied on acid-etched dentin. Significance The ethanol wet-bonding technique may improve the infiltration of most of the adhesives used in this study into dentin, especially when applied to EDTA-treated dentin. The chemical composition of the resin blends was a determining factor influencing the ability of adhesives to bond to EDTA-treated or 37% H3PO4 acid-etched dentin, when using the ethanol wet-bonding technique in a clinically relevant time period. PMID:20074787

  19. EDTA and HCl leaching of calcareous and acidic soils polluted with potentially toxic metals: remediation efficiency and soil impact.

    PubMed

    Udovic, Metka; Lestan, Domen

    2012-07-01

    The environmental risk of potentially toxic metals (PTMs) in soil can be diminished by their removal. Among the available remediation techniques, soil leaching with various solutions is one of the most effective but data about the impact on soil chemical and biological properties are still scarce. We studied the effect of two common leaching agents, hydrochloric acid (HCl) and a chelating agent (EDTA) on Pb, Zn, Cd removal and accessibility and on physico-chemical and biological properties in one calcareous, pH neutral soil and one non-calcareous acidic soil. EDTA was a more efficient leachant compared to HCl: up to 133-times lower chelant concentration was needed for the same percentage (35%) of Pb removal. EDTA and HCl concentrations with similar PTM removal efficiency decreased PTM accessibility in both soils but had different impacts on soil properties. As expected, HCl significantly dissolved carbonates from calcareous soil, while EDTA leaching increased the pH of the acidic soil. Enzyme activity assays showed that leaching with HCl had a distinctly negative impact on soil microbial and enzyme activity, while leaching with EDTA had less impact. Our results emphasize the importance of considering the ecological impact of remediation processes on soil in addition to the capacity for PTM removal.

  20. Photodynamic therapy with 5-aminoolevulinic acid-induced porphyrins and DMSO/EDTA for basal cell carcinoma

    NASA Astrophysics Data System (ADS)

    Warloe, Trond; Peng, Qian; Heyerdahl, Helen; Moan, Johan; Steen, Harald B.; Giercksky, Karl-Erik

    1995-03-01

    Seven hundred sixty three basal cell carcinomas (BCCs) in 122 patients were treated by photodynamic therapy by 5-aminolevulinic acid (ALA) in cream topically applied, either alone, in combination with dimethyl sulphoxide (DMSO) and ethylenediaminetetraacetic acid disodium salt (EDTA), or with DMSO as a pretreatment. After 3 hours cream exposure 40 - 200 Joules/cm2 of 630 nm laser light was given. Fluorescence imaging of biopsies showed highly improved ALA penetration depth and doubled ALA-induced porphyrin production using DMSO/EDTA. Treatment response was recorded after 3 months. After a single treatment 90% of 393 superficial lesions responded completely, independent of using DMSO/EDTA. In 363 nodulo-ulcerative lesions the complete response rate increased from 67% to above 90% with DMSO/EDTA for lesions less than 2 mm thickness and from 34% to about 50% for lesions thicker than 2 mm. Recurrence rate observed during a follow-up period longer than 12 months was 2 - 5%. PDT of superficial thin BCCs with ALA-induced porphyrins and DMSO/EDTA equals surgery and radiotherapy with respect to cure rate and recurrence. Cosmetic results of ALA-based PDT seemed to be better than those after other therapies. In patients with the nevoid BCC syndrome the complete response rate after PDT was far lower.

  1. EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid.

    PubMed

    Kanchana, P; Sekar, C

    2014-09-01

    Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142 nM over a wide concentration range from 1 × 10(-7) to 3 × 10(-5)M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples.

  2. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  3. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  4. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  5. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  6. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  7. 21 CFR 172.120 - Calcium disodium EDTA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium disodium EDTA. 172.120 Section 172.120... disodium EDTA. The food additive calcium disodium EDTA (calcium disodium ethylene-diaminetetraacetate) may.... 1 By weight of egg yolk portion. (2) With disodium EDTA (disodium ethylenediaminetetraacetate)...

  8. In vitro genotoxicity and cytotoxicity in murine fibroblasts exposed to EDTA, NaOCl, MTAD and citric acid.

    PubMed

    Marins, Juliana Soares Roter; Sassone, Luciana Moura; Fidel, Sandra Rivera; Ribeiro, Daniel Araki

    2012-01-01

    The aim of the present study was to evaluate the capacity of some root canal irrigants to induce genetic damage and/or cellular death in vitro. Murine fibroblast cells were exposed to ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl), MTAD™ and citric acid in increasing concentrations for 3 h at 37ºC. The negative control group was treated with vehicle control (phosphate buffer solution - PBS) for 3 h at 37°C, and the positive control group was treated with methylmetanesulfonate, 1 μM. for 3 h at 37°C. Cytotoxicity was assessed by the trypan blue test and genotoxicity was evaluated by the single cell gel (comet) assay. The results showed that exposure to 2.5% and 5% NaOCl and 8.5% citric acid resulted in a significant cytotoxic effect. NaOCl, EDTA and citric acid did not produce genotoxic effects with respect to the comet assay data for all evaluated concentrations. Although MTAD was not a cytotoxic agent, it showed significant genotoxic effects at all tested concentrations (ANOVA and Tukey's test; p<0.05). NaOCl, EDTA and citric acid were found to be cytotoxic in a dose-dependent manner, but they were not genotoxic. MTAD did not cause cell death, but presented genotoxic effects.

  9. Gibberellic acid, kinetin, and the mixture indole-3-acetic acid-kinetin assisted with EDTA-induced lead hyperaccumnulation in alfalfa plants.

    PubMed

    López, Martha L; Peralta-Videa, José R; Parsons, Jason G; Benitez, Tenoch; Gardea-Torresdey, Jorge L

    2007-12-01

    There are a few plant species considered potential hyperaccumulators for heavy metals, particularly lead (Pb). In this study, alfalfa plants grown in hydroponics were exposed to Pb at 40 mg/L, ethylenediaminetetraacetic acid (EDTA) equimolar to Pb, and 1, 10, and 100 microM concentrations of the phytohormones indole-3-acetic acid (IAA), gibberellic acid (GA), and kinetin (KN) and a mixture of IAA and KN at 100 microM each. Metal quantification by inductively coupled plasma/optical emission spectroscopy demonstrated that plants treated with Pb/EDTA plus KN at 1, 10, and 100 microM increased the Pb concentration in alfalfa leaves (compared to Pb alone) by factors of 17, 43, and 67, respectively, and by factors of 2, 5, and 8, respectively, compared to the Pb/EDTA treatment. The correlation coefficient between the Pb concentration in leaves and the concentrations of KN in the medium was 0.9993. In addition, the leaves of plants exposed to a Pb/EDTA/100 microM IAA-KN mixture had approximately 9500 mg of Pb/kg of dry weight, demonstrating that non-Pb hyperaccumulating plants could hyperaccumulate Pb when treated with EDTA and a mixture of IAA-KN. The X-ray absorption spectroscopic studies demonstrated that the absorption and translocation of Pb was in the same oxidation state as the supplied Pb(II).

  10. Effect of EDTA, HCl, and citric acid on Ca salt removal from Asian (silver) carp scales prior to gelatin extraction.

    PubMed

    Wang, Yan; Regenstein, Joe M

    2009-08-01

    Pretreatments with different chemicals at different concentrations to remove Ca compounds were studied to determine their effects on gelatin extraction from silver carp (Hypophthalmichthys molitrix) scales. During Ca removal with HCl, citric acid, and EDTA, all 3 chemicals were able to decalcify (>90%) scales; however, protein losses with EDTA were lower than with HCl and citric acid (P < 0.05), and protein losses with citric acid were lower than with HCl (P < 0.05). Ca removal with HCl yielded a solution where 4% to 5% of the protein was Hyp, with estimated gelatin losses from 0.9% to 2.5%. After 0.20 mol/L HCl was used for Ca removal, the extracted gelatin solution was 15.4% of the initial scales weight and gave a gel strength of 128 g. After using 1.2 g/L citric acid for Ca removal, the extracted gelatin solution was only 9% of the scales and the gel strength was 97 g. Using 0.20 mol/L EDTA for Ca removal gave a yield of 22% and a gel strength of 152 g. These data suggest that EDTA at 0.20 mol/L provides the best Ca removal with minimal collagen/gelatin removal (estimated gelatin loss was less than 0.013%) during the Ca removal step, and subsequently gave a high gelatin yield and gel strength. Fish gelatin has generally been extracted from fish skins and occasionally fish bones. This article focuses on removing the Ca compounds in fish scales and then producing fish gelatin with a good gel strength and yield. With further studies, this study may help the fish industry to have a new source of fish gelatin for food and pharmaceutical applications.

  11. Effects of simulated acid rain, EDTA, or their combination, on migration and chemical fraction distribution of extraneous metals in Ferrosol.

    PubMed

    Wen, Fang; Hou, Hong; Yao, Na; Yan, Zengguang; Bai, Liping; Li, Fasheng

    2013-01-01

    A laboratory repacked soil-leaching column experiment was conducted to study the effects of simulated acid rain or EDTA by themselves or in combination, on migration and chemical speciation distribution of Pb and its alternative rare metals including Ag, Bi, In, Sb, and Sn. Experimental results demonstrate that leaching with simulated acid rain promoted the migration of Bi, In and Pb, and their migration reached down to 8 cm in the soil profile, no enhancement of Sb, Ag or Sn migration was observed. Addition of EDTA significantly enhanced the migration of all six metals, especially Bi, In and Pb. The migration of metals was in the order Pb>Bi>In>Sb>Sn>Ag. The individual and combined effects of acid rain and EDTA increased the environmental risk of metals, by increasing the soluble content of metals in soil solutions and the relative distribution of the exchangeable fraction. Leaching risks of Bi, In and Pb were higher than other three metals. PMID:22921654

  12. Ethylene Diamine Tetraacetic Acid Etched Quantum Dots as a "Turn-On" Fluorescence Probe for Detection of Trace Zinc in Food.

    PubMed

    Liu, Wei; Wei, Fangdi; Xu, Guanhong; Wu, Yanzi; Hu, Chunting; Song, Quan; Yang, Jing; Hu, Qin

    2016-06-01

    In the present paper, a simple and rapid "turn-on" fluorescence sensor for Zn2+ based on ethylene diamine tetraacetic acid (EDTA) etched CdTe quantum dots (QDs) was developed. First, the initial bright fluorescence of mercaptopropionic acid (MPA) capped CdTe QDs was effectively quenched by EDTA, and then the presence of Zn2+ could "turn on" the weak fluorescence of QDs quenched by EDTA due to the formation of ZnS passivation shell. The increase of fluorescence intensity of EDTA etched QDs was found to be linear with the concentration of Zn2+ added. Under the optimum conditions, the calibration curve of this method showed good linearity in the concentration range of 9.1-1 09.1 μM of Zn2+ with the correlation coefficient R2 = 0.998. The limit of detection (3σ/K) was 2 μM. The developed QDs-based sensor was successfully applied to detect trace zinc in zinc fortified table salts and energy drinks with satisfactory results. PMID:27427745

  13. Effect of EDTA and Phosphoric Acid Pretreatment on the Bonding Effectiveness of Self-Etch Adhesives to Ground Enamel

    PubMed Central

    Ibrahim, Ihab M.; Elkassas, Dina W.; Yousry, Mai M.

    2010-01-01

    Objectives: This in vitro study determined the effect of enamel pretreatment with phosphoric acid and ethylenediaminetetraacetic acid (EDTA) on the bond strength of strong, intermediary strong, and mild self-etching adhesive systems. Methods: Ninety sound human premolars were used. Resin composite cylinders were bonded to flat ground enamel surfaces using three self-etching adhesive systems: strong Adper Prompt L-Pop (pH=0.9–1.0), intermediary strong AdheSE (pH=1.6–1.7), and mild Frog (pH=2). Adhesive systems were applied either according to manufacturer instructions (control) or after pretreatment with either phosphoric acid or EDTA (n=10). After 24 hours, shear bond strength was tested using a universal testing machine at a cross-head speed of 0.5 mm/minute. Ultra-morphological characterization of the surface topography and resin/enamel interfaces as well as representative fractured enamel specimens were examined using scanning electron microscopy (SEM). Results: Neither surface pretreatment statistically increased the mean shear bond strength values of either the strong or the intermediary strong self-etching adhesive systems. However, phosphoric acid pretreatment significantly increased the mean shear bond strength values of the mild self-etching adhesive system. SEM examination of enamel surface topography showed that phosphoric acid pretreatment deepened the same etching pattern of the strong and intermediary strong adhesive systems but converted the irregular etching pattern of the mild self-etching adhesive system to a regular etching pattern. SEM examination of the resin/enamel interface revealed that deepening of the etching pattern was consistent with increase in the length of resin tags. EDTA pretreatment had a negligible effect on ultra-morphological features. Conclusions: Use of phosphoric acid pretreatment can be beneficial with mild self-etching adhesive systems for bonding to enamel. PMID:20922162

  14. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  15. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  16. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  17. Kinetic Modeling of Esterification of Ethylene Glycol with Acetic Acid

    NASA Astrophysics Data System (ADS)

    Yadav, Vishnu P.; Mukherjee, Rudra Palash; Bantraj, Kandi; Maity, Sunil K.

    2010-10-01

    The reaction kinetics of the esterification of ethylene glycol with acetic acid in the presence of cation exchange resin has been studied and kinetic models based on empirical and Langmuir approach has been developed. The Langmuir based model involving eight kinetic parameters fits experimental data much better compared to empirical model involving four kinetic parameters. The effect of temperature and catalyst loading on the reaction system has been analyzed. Further, the activation energy and frequency factor of the rate constants for Langmuir based model has been estimated.

  18. Kinetic Modeling of Esterification of Ethylene Glycol with Acetic Acid

    SciTech Connect

    Yadav, Vishnu P.; Maity, Sunil K.; Mukherjee, Rudra Palash; Bantraj, Kandi

    2010-10-26

    The reaction kinetics of the esterification of ethylene glycol with acetic acid in the presence of cation exchange resin has been studied and kinetic models based on empirical and Langmuir approach has been developed. The Langmuir based model involving eight kinetic parameters fits experimental data much better compared to empirical model involving four kinetic parameters. The effect of temperature and catalyst loading on the reaction system has been analyzed. Further, the activation energy and frequency factor of the rate constants for Langmuir based model has been estimated.

  19. Ethylene Production and 1-Aminocyclopropane-1-Carboxylic Acid Conjugation in Thermoinhibited Cicer arietinum L. Seeds.

    PubMed

    Gallardo, M; Delgado, M del M; Sánchez-Calle, I M; Matilla, A J

    1991-09-01

    The effect of supraoptimal temperatures (30 degrees C, 35 degrees C) on germination and ethylene production of Cicer arietinum (chick-pea) seeds was measured. Compared with a 25 degrees C control, these temperatures inhibited both germination and ethylene production. The effect of supraoptimal temperatures could be alleviated by treating the seeds with ethylene. It was concluded that one effect of high temperature on germination was due to its negative effect on ethylene production. This inhibitory effect of high temperature was due to increased conjugation of 1-aminocyclopropane-1-carboxylic acid to 1-(malonylamino)cyclopropane-1-carboxylic acid and to an inhibition of ethylene-forming enzyme activity.

  20. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol,...

  1. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol,...

  2. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol,...

  3. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol,...

  4. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol,...

  5. Effect of the anticoagulant ethylenediamine tetra-acetic acid (EDTA) on the estimation of pharmacokinetic parameters: A case study with tigecycline and ciprofloxacin.

    PubMed

    Chen, Q; Tung, E C; Ciccotto, S L; Strauss, J R; Ortiga, R; Ramsay, K A; Tang, W

    2008-01-01

    Tigecycline and ciprofloxacin were employed as the model compounds to study the effect of the anticoagulant ethylenediamine tetra-acetic acid (EDTA), which is used during plasma sample preparations, on the determination of pharmacokinetic parameters. The pharmacokinetic parameters were determined in rats following intravenous infusion with blood samples collected in serum separators, with either EDTA- or heparin-coated tubes. The blood-to-plasma (B:P) partition ratio and plasma protein binding were determined in vitro in rat or human blood collected in either EDTA- or heparin-coated tubes. Drug concentrations were quantified by liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS) analysis. In tigecycline-treated rats drug concentrations were twofold lower in EDTA plasma, leading to a twofold lower area under plasma concentration-time curve (AUC) and twofold higher plasma clearance values as compared with those obtained from heparin plasma. No differences were noted in the pharmacokinetic parameters obtained from heparin-treated plasma versus serum. The B:P partition ratio and unbound fraction for tigecycline were significantly higher in EDTA-treated blood. When normalized to the B:P partition ratios, the tigecycline blood clearance values were identical between samples collected in EDTA- or heparin-coated tubes. Similar but smaller differences were observed for ciprofloxacin. It was concluded that EDTA might compete with tigecycline and ciprofloxacin for chelating metal ions and thus affect drug partition between blood and plasma compartments, leading to inaccurate measurement of pharmacokinetic parameters in plasma. PMID:17963190

  6. Enhanced ethylene emissions from red and Norway spruce exposed to acidic mists

    SciTech Connect

    Chen, Yimin; Wellburn, A.R. )

    1989-09-01

    Acidic cloudwater is believed to cause needle injury and to decrease winter hardiness in conifers. During simulations of these adverse conditions, rates of ethylene emissions from and levels of 1-aminocyclopropane-1-carboxylic acid (ACC) in both red and Norway spruce needles increased as a result of treatment with acidic mists but amounts of 1-malonyl(amino)cyclopropane-1-carboxylic acid remained unchanged. However, release of significant quantities of ethylene by another mechanism independent of ACC was also detected from brown needles. Application of exogenous plant growth regulators such as auxin, kinetic, abscisic acid and gibberellic acid (each 0.1 millimolar) had no obvious effects on the rates of basal or stress ethylene production from Norway spruce needles. The kinetics of ethylene formation by acidic mist-stressed needles suggest that there is no active inhibitive mechanism in spruce to prevent stress ethylene being released once ACC has been formed.

  7. Effect Of EDTA On Luminescence Property Of Eu{sup +3} Doped YPO{sub 4} Nanoparticles

    SciTech Connect

    Parchur, A. K.; Okram, G. S.; Singh, R. A.; Tewari, R.; Pradhan, Lina; Vatsa, R. K.; Ningthoujam, R. S.

    2010-12-01

    Nanoparticles of Eu{sup 3+} doped YPO{sub 4} have been prepared using ethylene glycol (EG). Ethylene diamine tetra acetic acid (EDTA) is used as a complexing agent. X-ray diffraction results show that the nanoparticles are crystalline in tetragonal structure. Based on William-Hall relation, the effective crystallite size and strain developed in lattice are found to be 28 nm and 0.002, respectively. With the addition of EDTA, there is a slight shift towards the lower wavelength in emission peaks. Asymmetric ratio of electric to magnetic dipole transition intensities are found to decrease with addition of EDTA. Emission intensity decreases with EDTA because of decrease of particle size as well as decrease of number of Eu{sup 3+} activators per unit volume. These materials are dispersible in water, which may have potential biological applications.

  8. Simultaneous extraction of Cr(VI) and Cu(II) from humic acid with new synthesized EDTA derivatives.

    PubMed

    Zhang, Tao; Wu, Ying-Xin; Huang, Xiong-Fei; Liu, Jun-Min; Xia, Bing; Zhang, Wei-Hua; Qiu, Rong-Liang

    2012-07-01

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid and its salts (EDTA) is very effective at removing cationic metals and has been utilized globally. However it is ineffective for anionic metal contaminants or metals bound to soil organic matter. The simultaneous removal of cationic and anionic metal contaminants by soil washing is difficult due to differences in their properties. The present study evaluated the potential of a washing process using two synthesized EDTA-derivatives, C(6)HEDTA (2,2'-((2-((carboxymethyl)(2-(hexanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid) and C(12)HEDTA (2,2'-((2-((carboxymethyl) (2-(dodecanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid), which consist of a hydrophilic polycarboxylic moiety and a hydrophobic moiety with a monoalkyl ester group. A series of equilibrium batch experiments at room temperature were conducted to investigate the efficacy of C(6)HEDTA and C(12)HEDTA as extractants for both oxyanion Cr(VI) and cationic Cu(II). Results showed that either C(6)HEDTA or C(12)HEDTA can extract both Cr(VI) and Cu(II) from humic acid simultaneously. However, C(6)HEDTA was less effective for Cr(VI) probably because it has no surface activities to increase solubility of humic acid, like C(12)HEDTA. Extraction of Cr(VI) was mainly attributed to the decreased surface tension and enhanced solubility of organic matter. Extraction of Cu(II) was attributed to both the Cu(II) chelation and enhanced solubility of humic acid. It was demonstrated that the hydrophilic polycarboxylic moiety of C(12)HEDTA chelates cations while the monoalkyl ester group produces surface active properties that enhance the solubility of humic acid.

  9. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  10. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  11. Effects of Tetracycline, EDTA and Citric Acid Application on Nonfluorosed and Fluorosed Dentin: An In Vitro Study

    PubMed Central

    Sadanand, K.; Vandana, K. L.

    2016-01-01

    Fluorosis is one of the factors that may bring about mineralization changes in teeth. Routine treatment of root biomodification is commonly followed during Periodontal therapy. Background: The Purpose of the present study was to compare and evaluate the morphological changes in fluorosed and nonfluorosed root dentin subsequent to the application of Tetracycline, EDTA and Citric acid. Both fluorosed and nonfluorosed teeth comprising of periodontally healthy and diseased were included in this study. Method: Each of them was grouped into Tetracycline Hydrochloride, EDTA and Citric acid treatment groupes. Using scanning electron microscope (SEM), the photomicrographs of dentin specimens were obtained. Results: Showed that there was no significant difference in exposure of number of tubules in different groups, while significant increase in the tubular width and tubular surface area was seen in fluorosed healthy, followed by fluorosed diseased groups, nonfluorosed healthy and nonfluorosed diseased groups after root biomodification procedure using various root conditioning agents. The root biomodification procedure brings in definite difference between fluorosed and nonfluorosed dentin specimens. PMID:27335611

  12. Spectral filters based on ethylene/acrylic acid copolymer ionomers

    SciTech Connect

    Riley, M.O.; Walkup, C.M.; Hagen, W.F.; Jessop, E.S.

    1988-09-01

    We are investigating the possibility of utilizing ionomers as inexpensive, easily replaced optical filters for applications in large fusion lasers as well as high average power solid state lasers. To this end we have synthesized a number of other derivatives of the ethylene/acrylic acid (EAA) copolymer system. Specifically, we prepared several ionomers at nominal 3 wt. % metal ion concentration, including Fe(III), Co(II), Ni(II), Cu(II), and Ce(III), by reacting aqueous solutions of metal acetates or nitrates with aqueous ammonia dispersions (1) of EAA as described previously. The products were compression molded into thin optically clear films under the above-described conditions. A gel was formed in a similar reaction with samarium (III) nitrate. Accordingly, the samarium ionomer was synthesized by a melt phase reaction between the EAA resin and the metal nitrate. 6 refs., 2 figs., 2 tabs.

  13. An Aqueous Thermodynamic Model for the Complexation of Sodium and Strontium with Organic Chelates valid to High Ionic Strength. I. Ethylenedinitrilotetraacetic acid (EDTA)

    SciTech Connect

    Felmy, Andrew R.; Mason, Marvin J.

    2003-04-01

    An aqueous thermodynamic model is developed, which accurately describes the effects of Na+ complexation, ionic strength, carbonate concentration, and temperature on the complexation of Sr2+ by ethylenedinitrilotetraacetic acid (EDTA) under basic conditions. The model is developed from the analysis of literature data on apparent equilibrium constants, enthalpies, and heat capacities; as well as on an extensive set of solubility data on SrCO3(c) in the presence of EDTA obtained as part of this study. The solubility data for SrCO3(c) were obtained in solutions ranging in Na2CO3 concentration from 0.01m to 1.8m, in NaNO3 concentration from 0 to 5m, and at temperatures extending to 75?C. The final aqueous thermodynamic model is based upon the equations of Pitzer and requires the inclusion of a NaEDTA3- species. An accurate model for the ionic strength dependence of the ion-interaction coefficients for the SrEDTA2- and NaEDTA3- aqueous species allows the extrapolation of standard state equilibrium constants for these species which are significantly different from the 0.1m reference state values available in the literature. The final model is tested by application to chemical systems containing competing metal ions (i.e., Ca2+) to further verify the proposed model and indicate the applicability of the model parameters to chemical systems containing other divalent metal-EDTA complexes.

  14. Ecological Risk Assessment of EDTA-Assisted Phytoremediation of Cd Under Different Cultivation Systems.

    PubMed

    Luo, Jie; Qi, Shihua; Gu, X W Sophie; Hou, Tao; Lin, Lihong

    2016-02-01

    A long-term field experiment was designed to assess remediation efficiency and ecological risk of phytoremediation of Cd under different cultivation systems with or without ethylene diamine tetraacetic acid (EDTA). EDTA can significantly improve the phytoremediation effectiveness of a historically polluted e-waste dismantling site through enhancing Cd uptake by plants in all cultivation systems along with higher ecological risks to different receptors especially in the presence of Cicer arietinum (chickpea). Moisture content at each layer of soil profile under Eucalyptus globules L. cultivated sites was consistently lower than under chickpea monoculture as a result of E. globules' high water use efficiency. Besides low soil moisture, E. globules can intercept more Cd-rich leachate than chickpea regardless of the presence of EDTA. E. globules could be used for Cd phytoremediation as they can take full advantage of EDTA and decrease ecological risk caused by the chelator.

  15. Effect of EDTA and Tannic Acid on the Removal of Cd, Ni, Pb and Cu from Artificially Contaminated Soil by Althaea rosea Cavan.

    PubMed

    Cay, Seydahmet; Uyanik, Ahmet; Engin, Mehmet Soner; Kutbay, Hamdi Guray

    2015-01-01

    In this study an ornamental plant of Althaea rosea Cavan was investigated for its potential use in the removal of Cd, Ni, Pb and Cu from an artificially contaminated soil. Effect of two different chelating agents on the removal has also been studied by using EDTA (ethylenediaminetetracetic acid) and TA (tannic acid). Both EDTA and TA have led to higher heavy metal concentration in shoots and leaves compared to control plants. However EDTA is generally known as an effective agent in metal solubilisation of soil, in this study, TA was found more effective to induce metal accumulation in Althaea rosea Cavan under the studied conditions. In addition to this, EDTA is toxic to some species and restraining the growth of the plants. The higher BCF (Bio Concentration Factor) and TF (Translocation Factor) values obtained from stems and leaves by the effects of the chemical enhancers (EDTA and TA) show that Althaea rosea Cavan is a hyper accumulator for the studied metals and may be cultivated to clean the contaminated soils.

  16. Comparison of EDTA and EDDS as potential soil amendments for enhanced phytoextraction of heavy metals.

    PubMed

    Meers, E; Ruttens, A; Hopgood, M J; Samson, D; Tack, F M G

    2005-02-01

    Phytoextraction has been proposed as an alternative remediation technology for soils polluted with heavy metals or radionuclides, but is generally conceived as too slow working. Enhancing the accumulation of trace pollutants in harvestable plant tissues is a prerequisite for the technology to be practically applicable. The chelating aminopolycarboxylic acid, ethylene diamine tetraacetate (EDTA), has been found to enhance shoot accumulation of heavy metals. However, the use of EDTA in phytoextraction may not be suitable due to its high environmental persistence, which may lead to groundwater contamination. This paper aims to assess whether ethylene diamine disuccinate (EDDS), a biodegradable chelator, can be used for enhanced phytoextraction purposes. A laboratory experiment was conducted to examine mobilisation of Cd, Cu, Cr, Ni, Pb and Zn into the soil solution upon application of EDTA or EDDS. The longevity of the induced mobilisation was monitored for a period of 40 days after application. Estimated effect half lives ranged between 3.8 and 7.5 days for EDDS, depending on the applied dose. The minimum observed effect half life of EDTA was 36 days, while for the highest applied dose no decrease was observed throughout the 40 day period of the mobilisation experiment. Performance of EDTA and EDDS for phytoextraction was evaluated by application to Helianthus annuus. Two other potential chelators, known for their biodegradability in comparison to EDTA, were tested in the plant experiment: nitrilo acetic acid (NTA) and citric acid. Uptake of heavy metals was higher in EDDS-treated pots than in EDTA-treated pots. The effects were still considered insufficiently high to consider efficient remediation. This may be partly due to the choice of timing for application of the soil amendment. Fixing the time of application at an earlier point before harvest may yield better results. NTA and citric acid induced no significant effects on heavy metal uptake.

  17. Low concentration of ethylenediaminetetraacetic acid (EDTA) affects biofilm formation of Listeria monocytogenes by inhibiting its initial adherence.

    PubMed

    Chang, Yuhua; Gu, Weimin; McLandsborough, Lynne

    2012-02-01

    The distribution and survival of the food-borne pathogen Listeria monocytogenes is associated with its biofilm formation ability, which is affected by various environmental factors. Here we present the first evidence that EDTA at low concentration levels inhibits the biofilm formation of L. monocytogenes. This effect of EDTA is not caused by a general growth inhibition, as 0.1 mM EDTA efficiently reduced the biofilm formation of L. monocytogenes without affecting the planktonic growth. Adding 0.1 mM of EDTA at the starting time of biofilm formation had the strongest biofilm inhibitory effect, while the addition of EDTA after 8 h had no biofilm inhibitory effects. EDTA was shown to inhibit cell-to-surface interactions and cell-to-cell interactions, which at least partially contributed to the repressed initial adherence. The addition of sufficient amounts of cations to saturate EDTA did not restore the biofilm formation, indicating the biofilm inhibition was not due to the chelating properties of EDTA. The study suggests that EDTA functions in the early stage of biofilm process by affecting the initial adherence of L. monocytogenes cells onto abiotic surfaces.

  18. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    PubMed

    Song, Yue; Ammami, Mohamed-Tahar; Benamar, Ahmed; Mezazigh, Salim; Wang, Huaqing

    2016-06-01

    In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of different chelating agents (ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA) or citric acid (CA)) in enhancing EK remediation efficiency. The results show that, for the same concentration (0.1 mol L(-1)), EDTA is more suitable to enhance removal of Ni (52.8 %), Pb (60.1 %) and Zn (34.9 %). EDDS provides effectiveness to increase Cu removal efficiency (52 %), while EDTA and EDDS have a similar enhancement removal effect on As EK remediation (30.5∼31.3 %). CA is more suitable to enhance Cd removal (40.2 %). Similar Cr removal efficiency was provided by EK remediation tests (35.6∼43.5 %). In the migration of metal-chelate complexes being directed towards the anode, metals are accumulated in the middle sections of the sediment matrix for the tests performed with EDTA, NTA and CA. But, low accumulation of metal contamination in the sediment was observed in the test using EDDS. PMID:26782321

  19. Enhancement of electrokinetic decontamination with EDTA.

    PubMed

    Karim, M A; Khan, L I

    2012-01-01

    The effect of ethylenediaminetetraacetic acid (EDTA) during electrokinetic decontamination (EKD) was investigated in this research. EDTA is a ligand that can form soluble complexes with precipitated heavy metals inside soil pores. Millpond sludge, primarily contaminated with lead (Pb) and zinc (Zn), was subjected to EKD with and without the presence of EDTA. Dilute EDTA solutions with strengths of 0.05 M and 0.125 M were injected into the millpond sludge by electroosmosis. Several beneficial effects of using EDTA were observed in this research. One was that the presence of EDTA substantially increased the electroosmotic (EO) flow in the millpond sludge indicating that it could significantly reduce the duration of EKD. Another advantage was that a significantly higher percentage of Pb and Zn removal was achieved from the solid phase due to the complexation of EDTA with these heavy metals. Also, EDTA was able to prevent the precipitation of metals at the cathode electrode, typically observed in EKD process. PMID:23393970

  20. Altered Cultivar Resistance of Kimchi Cabbage Seedlings Mediated by Salicylic Acid, Jasmonic Acid and Ethylene

    PubMed Central

    Lee, Young Hee; Kim, Sang Hee; Yun, Byung-Wook; Hong, Jeum Kyu

    2014-01-01

    Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ) treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner. PMID:25289020

  1. Influence of variable chemical conditions on EDTA-enhanced transport of metal ions in mildly acidic groundwater

    USGS Publications Warehouse

    Kent, D.B.; Davis, J.A.; Joye, J.L.; Curtis, G.P.

    2008-01-01

    Adsorption of Ni and Pb on aquifer sediments from Cape Cod, Massachusetts, USA increased with increasing pH and metal-ion concentration. Adsorption could be described quantitatively using a semi-mechanistic surface complexation model (SCM), in which adsorption is described using chemical reactions between metal ions and adsorption sites. Equilibrium reactive transport simulations incorporating the SCMs, formation of metal-ion-EDTA complexes, and either Fe(III)-oxyhydroxide solubility or Zn desorption from sediments identified important factors responsible for trends observed during transport experiments conducted with EDTA complexes of Ni, Zn, and Pb in the Cape Cod aquifer. Dissociation of Pb-EDTA by Fe(III) is more favorable than Ni-EDTA because of differences in Ni- and Pb-adsorption to the sediments. Dissociation of Ni-EDTA becomes more favorable with decreasing Ni-EDTA concentration and decreasing pH. In contrast to Ni, Pb-EDTA can be dissociated by Zn desorbed from the aquifer sediments. Variability in adsorbed Zn concentrations has a large impact on Pb-EDTA dissociation.

  2. EDTA retention and emissions from remediated soil.

    PubMed

    Jez, Erika; Lestan, Domen

    2016-05-01

    EDTA-based remediation is reaching maturity but little information is available on the state of chelant in remediated soil. EDTA soil retention was examined after extracting 20 soil samples from Pb contaminated areas in Slovenia, Austria, Czech Republic and USA with 120 mM kg(-1) Na2H2EDTA, CaNa2EDTA and H4EDTA for 2 and 24 h. On average, 73% of Pb was removed from acidic and 71% from calcareous soils (24 h extractions). On average, 15% and up to 64% of applied EDTA was after remediation retained in acidic soils. Much less; in average 1% and up to the 22% of EDTA was retained in calcareous soils. The secondary emissions of EDTA retained in selected remediated soil increased with the acidity of the media: the TCLP (Toxicity Characteristic Leaching Procedure) solution (average pH end point 3.6) released up to 36% of EDTA applied in the soil (28.1 mmol kg(-1)). Extraction with deionised water (pH > 6.0) did not produce measurable EDTA emissions. Exposing soil to model abiotic (thawing/freezing cycles) and biotic (ingestion by earthworms Lumbricus rubellus) ageing factors did not induce additional secondary emissions of EDTA retained in remediated soil. PMID:26943741

  3. Regulation of Senescence in Carnation (Dianthus caryophyllus): Effect of Abscisic Acid and Carbon Dioxide on Ethylene Production.

    PubMed

    Mayak, S; Dilley, D R

    1976-11-01

    Abscisic acid hastened senescence of carnation flowers and this was preceded by stimulation of accelerated ethylene production. Carbon dioxide delayed the onset of autocatalytic ethylene production in flowers regardless of treatment with abscisic acid. Flowers exhibited a low and transient climacteric of ethylene production without wilting while in 4% carbon dioxide and underwent accelerated ethylene production culminating in wilting when removed from carbon dioxide. Hypobaric ventilation, which lowers ethylene to hyponormal levels within tissues, extended flower longevity and largely negated enhancement of senescence by abscisic acid. Supplementing hypobarically ventilated flowers with ethylene hastened senescence irrespective of abscisic acid treatment. Collectively, the data indicate that abscisic acid hastens senescence of carnations largely as a result of advancing the onset of autocatalytic ethylene production.

  4. Effects of nisin, EDTA and salts of organic acids on Listeria monocytogenes, Salmonella and native microflora on fresh vacuum packaged shrimps stored at 4 °C.

    PubMed

    Wan Norhana, M N; Poole, Susan E; Deeth, Hilton C; Dykes, Gary A

    2012-08-01

    Nisin (500 IU ml⁻¹), EDTA (0.02 M), potassium sorbate (PS) (3%, w/v), sodium benzoate (SB) (3%, w/v) or sodium diacetate (SD) (3%, w/v); alone or in combination were used to dip uninoculated shrimps and shrimps inoculated with Listeria monocytogenes or Salmonella (∼4.0-5.0 log CFU g⁻¹). Shrimps were then drip-dried, vacuum packaged and stored at 4 °C for 7 days. Untreated shrimps were used as a control. Numbers of L. monocytogenes, Salmonella and native background microflora were determined on uninoculated and inoculated shrimps on days 0, 3 and 7. Nisin-EDTA-PS and nisin-EDTA-SD significantly reduced (p < 0.05) L. monocytogenes numbers by 1.07-1.27 and 1.32-1.36 log CFU g⁻¹, respectively, on day 0 and 3. However, all treatments failed to significantly reduce (p > 0.05) Salmonella counts on shrimps throughout storage. On day 7, numbers of aerobic bacteria, psychrotrophic bacteria and Pseudomonas on combined nisin-EDTA-salt of organic acids treated shrimps were significantly lower (p < 0.05) by 4.40-4.60, 3.50-4.01, and 3.84-3.99 log CFU g⁻¹ respectively, as compared to the control. Dipping in organic acids solutions followed by vacuum packaging and chilled storage can help reduce L. monocytogenes and native microflora, but not Salmonella, on fresh shrimps. PMID:22475941

  5. Intermediates to ethylene glycol: carbonylation of formaldehyde catalyzed by Nafion solid perfluorosulfonic acid resin

    SciTech Connect

    Hendriksen, D.E.

    1983-01-01

    Details of a series of reactions for the production of ethylene glycol using a catalyst of Nafion solid perfluorosulfonic acid resin was detailed. The reactions included the carbonylation of formaldehyde and esterification and then hydrogenation of the product of the carbonylation, glycolic acid. Other preparations included in the work included methyl glycolate, acetylglycolic acid, methyl acetylglycolate, and methyl methoxyacetate.

  6. Ethylene-Enhanced 1-Aminocyclopropane-1-carboxylic Acid Synthase Activity in Ripening Apples 1

    PubMed Central

    Bufler, Gebhard

    1984-01-01

    Apples (Malus sylvestris Mill, cv Golden Delicious) were treated before harvest with aminoethoxyvinylglycine (AVG). AVG is presumed to reversibly inhibit 1-aminocyclopropane-1-carboxylic acid (ACC) activity, but not the formation of ACC synthase. AVG treatment effectively blocked initiation of autocatalytic ethylene production and ripening of harvested apples. Exogenous ethylene induced extractable ACC synthase activity and ripening in AVG-treated apples. Removal of exogenous ethylene caused a rapid decline in ACC synthase activity and in CO2 production. The results with ripened, AVG-treated apples indicate (a) a dose-response relationship between ethylene and enhancement of ACC synthase activity with a half-maximal response at approximately 0.8 μl/l ethylene; (b) reversal of ethylene-enhanced ACC synthase activity by CO2; (c) enhancement of ACC synthase activity by the ethylene-activity analog propylene. Induction of ACC synthase activity, autocatalytic ethylene production, and ripening of preclimacteric apples not treated with AVG were delayed by 6 and 10% CO2, but not by 1.25% CO2. However, each of these CO2 concentrations reduced the rate of increase of ACC synthase activity. PMID:16663569

  7. Synthesis and photochromic properties of EDTA-induced MoO{sub 3} powder

    SciTech Connect

    Yan, Minyan; Shen, Yi; Zhao, Li; Li, Zhen

    2011-10-15

    Graphical abstract: The MoO{sub 3} powder, which exhibits highly dispersed floral aggregated-like structure built up by superimposed and staggered nanoflakes with a diameter of 1-1.5 {mu}m and a thickness of 0.1-0.2 {mu}m, has been successfully obtained when the molar ratio of EDTA/Mo{sup 6+} is 0.05:1. The EDTA inducer obviously enlarges the surface area and apparently enhances the reactivity of MoO{sub 3} powders, making it show greater absorptive capacity to the excitation light and better photochromic properties than the pure MoO{sub 3} powder. Highlights: {yields} EDTA as organic inducing agent. {yields} EDTA inducer at EDTA/Mo{sup 6+} molar ratio of 0.05:1 enables growth of flower-like microspheres. {yields} The formation of flower-like MoO{sub 3} makes its photochromic properties strongly enhanced. -- Abstract: In this study, the photochromic MoO{sub 3} powder with novel morphology has been synthesized via hydrothermal method, using ethylene diamine tetraacetice acid (EDTA) as organic inducing agent. The influence of EDTA on the morphology, structure and photochromic properties of MoO{sub 3} powder has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), as well as ultraviolet and visible spectroscopy (UV-vis) and color difference meter. When the molar ratio of EDTA/Mo{sup 6+} is 0.05:1, the EDTA-induced MoO{sub 3} powder is found to have 3D flower-like morphologies and excellent photochromic properties. Furthermore, the possible growth mechanism of the flower-like structure and the photochromic mechanism of MoO{sub 3} powder are also discussed in detail.

  8. Miscibility and degradability of poly(lactic acid)poly(ethylene oxide)/poly(ethylene glycol) blends

    SciTech Connect

    Yue, C.L.; Dave, V.; Gross, R.A.; McCarthy, S.P.

    1995-12-01

    Poly(lactic acid) [PLA] was melt blended with polyethylene(oxide) [PEG] and poly(ethylene glycol) [PEG] in different compositions to form blown films. It was determined that PLA was miscible with PEO in all compositions. Based on Gordon-Taylor equation, it was determined that the interactions between PLA and PEO is stronger than PEG. The addition of low molecular weight PEG improved the elongation and tear strength of the blends. Enzymatic degradation results shows that the weight loss of all the samples was more than 80% of the initial weight in 48 hours.

  9. Influence of the selective EDTA derivative phenyldiaminetetraacetic acid on the speciation and extraction of heavy metals from a contaminated soil.

    PubMed

    Zhang, Tao; Wei, Hang; Yang, Xiu-Hong; Xia, Bing; Liu, Jun-Min; Su, Cheng-Yong; Qiu, Rong-Liang

    2014-08-01

    The development of more selective chelators for the washing of heavy metal contaminated soil is desirable in order to avoid excessive dissolution of soil minerals. Speciation and mobility of Cu, Zn, Pb, and Ni in a contaminated soil washed with phenyldiaminetetraacetic acid (PDTA), a derivative of EDTA, were investigated by batch leaching test using a range of soil washing conditions followed by sequential extraction. With appropriate washing conditions, PDTA significantly enhanced extraction of Cu from the contaminated soil. The primary mechanisms of Cu extraction by PDTA were complexation-promoted dissolution of soil Cu and increased dissolution of soil organic matter (SOM). PDTA showed high selectivity for Cu(II) over soil component cations (Ca(II), Mg(II), Fe(III), Mn(II), Al(III)), especially at lower liquid-to-soil ratios under PDTA deficiency, thus avoiding unwanted dissolution of soil minerals during the soil washing process which can degrade soil structure and interfere with future land use. PDTA-enhanced soil washing increased the exchangeable fractions of Cu, Zn, and Pb and decreased their residual fractions, compared to their levels in unwashed soil.

  10. The Effect of Ethylene and Propylene Pulses on Respiration, Ripening Advancement, Ethylene-Forming Enzyme, and 1-Aminocyclopropane-1-carboxylic Acid Synthase Activity in Avocado Fruit.

    PubMed

    Starrett, D A; Laties, G G

    1991-03-01

    When early-season avocado fruit (Persea americana Mill. cv Hass) were treated with ethylene or propylene for 24 hours immediately on picking, the time to the onset of the respiratory climacteric, i.e. the lag period, remained unchanged compared with that in untreated fruit. When fruit were pulsed 24 hours after picking, on the other hand, the lag period was shortened. In both cases, however, a 24 hour ethylene or propylene pulse induced a transient increase in respiration, called the pulse-peak, unaccompanied by ethylene production (IL Eaks [1980] Am Soc Hortic Sci 105: 744-747). The pulse also caused a sharp rise in ethylene-forming enzyme activity in both cases, without any increase in the low level of 1-aminocyclopropane-1-carboxylic acid synthase activity. Thus, the shortening of the lag period by an ethylene pulse is not due to an effect of ethylene on either of the two key enzymes in ethylene biosynthesis. A comparison of two-dimensional polyacrylamide gel electrophoresis polypeptide profiles of in vitro translation products of poly(A(+)) mRNA from control and ethylene-pulsed fruit showed both up- and down-regulation in response to ethylene pulsing of a number of genes expressed during the ripening syndrome. It is proposed that the pulse-peak or its underlying events reflect an intrinsic element in the ripening process that in late-season or continuously ethylene-treated fruit may be subsumed in the overall climacteric response. A computerized system that allows continuous readout of multiple samples has established that the continued presentation of exogeneous ethylene or propylene to preclimacteric fruit elicits a dual respiration response comprising the merged pulse-peak and climacteric peak in series. The sequential removal of cores from a single fruit has proven an unsatisfactory sampling procedure inasmuch as coring induces wound ethylene, evokes a positive respiration response, and advances ripening.

  11. Ethylene responses in rice roots and coleoptiles are differentially regulated by a carotenoid isomerase-mediated abscisic acid pathway.

    PubMed

    Yin, Cui-Cui; Ma, Biao; Collinge, Derek Phillip; Pogson, Barry James; He, Si-Jie; Xiong, Qing; Duan, Kai-Xuan; Chen, Hui; Yang, Chao; Lu, Xiang; Wang, Yi-Qin; Zhang, Wan-Ke; Chu, Cheng-Cai; Sun, Xiao-Hong; Fang, Shuang; Chu, Jin-Fang; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2015-04-01

    Ethylene and abscisic acid (ABA) act synergistically or antagonistically to regulate plant growth and development. ABA is derived from the carotenoid biosynthesis pathway. Here, we analyzed the interplay among ethylene, carotenoid biogenesis, and ABA in rice (Oryza sativa) using the rice ethylene response mutant mhz5, which displays a reduced ethylene response in roots but an enhanced ethylene response in coleoptiles. We found that MHZ5 encodes a carotenoid isomerase and that the mutation in mhz5 blocks carotenoid biosynthesis, reduces ABA accumulation, and promotes ethylene production in etiolated seedlings. ABA can largely rescue the ethylene response of the mhz5 mutant. Ethylene induces MHZ5 expression, the production of neoxanthin, an ABA biosynthesis precursor, and ABA accumulation in roots. MHZ5 overexpression results in enhanced ethylene sensitivity in roots and reduced ethylene sensitivity in coleoptiles. Mutation or overexpression of MHZ5 also alters the expression of ethylene-responsive genes. Genetic studies revealed that the MHZ5-mediated ABA pathway acts downstream of ethylene signaling to inhibit root growth. The MHZ5-mediated ABA pathway likely acts upstream but negatively regulates ethylene signaling to control coleoptile growth. Our study reveals novel interactions among ethylene, carotenogenesis, and ABA and provides insight into improvements in agronomic traits and adaptive growth through the manipulation of these pathways in rice.

  12. Enhanced bioconversion of ethylene glycol to glycolic acid by a newly isolated Burkholderia sp. EG13.

    PubMed

    Gao, Xiaoxin; Ma, Zhengfei; Yang, Limin; Ma, Jiangquan

    2014-10-01

    Burkholderia sp. EG13 with high ethylene glycol-oxidizing activity was isolated from soil, which could be used for the synthesis of glycolic acid from the oxidation of ethylene glycol. Using the resting cells of Burkholderia sp. EG13 as biocatalysts, the optimum reaction temperature and pH were 30 °C and 6.0, respectively. After 24 h of biotransformation, the yield of glycolic acid from 200 mM ethylene glycol was 98.8 %. Furthermore, an integrated bioprocess for the production of glycolic acid which involved in situ product removal (ISPR) was investigated. Using fed-batch method with ISPR, a total of 793 mM glycolic acid has been accumulated in the reaction mixture after the 4th feed.

  13. Abscisic Acid Regulates Root Elongation Through the Activities of Auxin and Ethylene in Arabidopsis thaliana

    PubMed Central

    Thole, Julie M.; Beisner, Erin R.; Liu, James; Venkova, Savina V.; Strader, Lucia C.

    2014-01-01

    Abscisic acid (ABA) regulates many aspects of plant growth and development, including inhibition of root elongation and seed germination. We performed an ABA resistance screen to identify factors required for ABA response in root elongation inhibition. We identified two classes of Arabidopsis thaliana AR mutants that displayed ABA-resistant root elongation: those that displayed resistance to ABA in both root elongation and seed germination and those that displayed resistance to ABA in root elongation but not in seed germination. We used PCR-based genotyping to identify a mutation in ABA INSENSITIVE2 (ABI2), positional information to identify mutations in AUXIN RESISTANT1 (AUX1) and ETHYLENE INSENSITIVE2 (EIN2), and whole genome sequencing to identify mutations in AUX1, AUXIN RESISTANT4 (AXR4), and ETHYLENE INSENSITIVE ROOT1/PIN-FORMED2 (EIR1/PIN2). Identification of auxin and ethylene response mutants among our isolates suggested that auxin and ethylene responsiveness were required for ABA inhibition of root elongation. To further our understanding of auxin/ethylene/ABA crosstalk, we examined ABA responsiveness of double mutants of ethylene overproducer1 (eto1) or ein2 combined with auxin-resistant mutants and found that auxin and ethylene likely operate in a linear pathway to affect ABA-responsive inhibition of root elongation, whereas these two hormones likely act independently to affect ABA-responsive inhibition of seed germination. PMID:24836325

  14. Abscisic Acid Antagonizes Ethylene-Induced Hyponastic Growth in Arabidopsis1[OA

    PubMed Central

    Benschop, Joris J.; Millenaar, Frank F.; Smeets, Maaike E.; van Zanten, Martijn; Voesenek, Laurentius A.C.J.; Peeters, Anton J.M.

    2007-01-01

    Ethylene induces enhanced differential growth in petioles of Arabidopsis (Arabidopsis thaliana), resulting in an upward movement of the leaf blades (hyponastic growth). The amplitude of this effect differs between accessions, with Columbia-0 (Col-0) showing a large response, while in Landsberg erecta (Ler), hyponastic growth is minimal. Abscisic acid (ABA) was found to act as an inhibitory factor of this response in both accessions, but the relationship between ethylene and ABA differed between the two; the ability of ABA to inhibit ethylene-induced hyponasty was significantly more pronounced in Col-0. Mutations in ABI1 or ABI3 induced a strong ethylene-regulated hyponastic growth in the less responsive accession Ler, while the response was abolished in the ABA-hypersensitive era1 in Col-0. Modifications in ABA levels altered petiole angles in the absence of applied ethylene, indicating that ABA influences petiole angles also independently from ethylene. A model is proposed whereby the negative effect of ABA on hyponastic growth is overcome by ethylene in Col-0 but not in Ler. However, when ABA signaling is artificially released in Ler, this regulatory mechanism is bypassed, resulting in a strong hyponastic response in this accession. PMID:17158582

  15. Abscisic acid regulates root elongation through the activities of auxin and ethylene in Arabidopsis thaliana.

    PubMed

    Thole, Julie M; Beisner, Erin R; Liu, James; Venkova, Savina V; Strader, Lucia C

    2014-05-15

    Abscisic acid (ABA) regulates many aspects of plant growth and development, including inhibition of root elongation and seed germination. We performed an ABA resistance screen to identify factors required for ABA response in root elongation inhibition. We identified two classes of Arabidopsis thaliana AR mutants that displayed ABA-resistant root elongation: those that displayed resistance to ABA in both root elongation and seed germination and those that displayed resistance to ABA in root elongation but not in seed germination. We used PCR-based genotyping to identify a mutation in ABA INSENSITIVE2 (ABI2), positional information to identify mutations in AUXIN RESISTANT1 (AUX1) and ETHYLENE INSENSITIVE2 (EIN2), and whole genome sequencing to identify mutations in AUX1, AUXIN RESISTANT4 (AXR4), and ETHYLENE INSENSITIVE ROOT1/PIN-FORMED2 (EIR1/PIN2). Identification of auxin and ethylene response mutants among our isolates suggested that auxin and ethylene responsiveness were required for ABA inhibition of root elongation. To further our understanding of auxin/ethylene/ABA crosstalk, we examined ABA responsiveness of double mutants of ethylene overproducer1 (eto1) or ein2 combined with auxin-resistant mutants and found that auxin and ethylene likely operate in a linear pathway to affect ABA-responsive inhibition of root elongation, whereas these two hormones likely act independently to affect ABA-responsive inhibition of seed germination.

  16. Acid-base equilibria in ethylene glycol--III: selection of titration conditions in ethylene glycol medium, protolysis constants of alkaloids in ethylene glycol and its mixtures.

    PubMed

    Zikolov, P; Zikolova, T; Budevsky, O

    1976-08-01

    Theoretical titration curves are used for the selection of appropriate conditions for the acid-base volumetric determination of weak bases in ethylene glycol medium. The theoretical curves for titration of some alkaloids are deduced graphically on the basis of the logarithmic concentration diagram. The acid-base constants used for the construction of the theoretical titration curves were determined by potentiometric titration in a cell without liquid junction, equipped with a glass and a silver-silver chloride electrode. It is shown that the alkaloids investigated can be determined accurately by visual or potentiometric titration. The same approach for the selection of titration conditions seems to be applicable to other non-aqueous amphiprotic solvents.

  17. The influence of ethylenediamine tetra acetic acid (EDTA) on the transformation and solubility of metallic palladium and palladium(II) oxide in the environment.

    PubMed

    Zereini, Fathi; Wiseman, Clare L S; Vang, My; Albers, Peter; Schneider, Wolfgang; Schindl, Roland; Leopold, Kerstin

    2015-05-01

    The environmental occurrence of elevated concentrations of platinum (Pt), palladium (Pd) and rhodium (Rh) from automotive catalytic converters has been well-documented. Limited information exists regarding their chemical behavior post-emission, however, especially in the presence of commonly occurring complexing agents. The purpose of this study is to examine the influence of ethylenediamine tetra acetic acid (EDTA) on the possible environmental transformation and solubility of Pd by conducting batch experiments using metallic palladium (Pd black) and palladium(ii) oxide (PdO). Changes in the particle surface chemistry of treated samples were analyzed using X-ray Photoelectron Spectroscopy (XPS) and Transition Electron Microscopy/Energy Dispersive X-ray Spectrometry (TEM/EDX) techniques. Metallic palladium was partially transformed into PdOx (x < 1), while PdO remained largely unaffected. The pH of EDTA solutions was observed to modulate Pd solubility, with Pd black demonstrating a higher solubility compared to PdO. Solubility was also found to increase with a corresponding increase in the strength of EDTA solution concentrations, as well as with the length of extraction time. The overall solubility of Pd remained relatively low for most samples (<1 wt%). A dissolution rate of 2.01 ± 0.17 nmol m(-2) h(-1) was calculated for Pd black in 0.1 M EDTA (pH 7). In contrast to previously held assumptions about the environmental immobility of Pd, small amounts of this element emitted in metallic form are likely to be soluble in the presence of complexing agents such as EDTA.

  18. Ethylene limits abscisic acid- or soil drying-induced stomatal closure in aged wheat leaves.

    PubMed

    Chen, Lin; Dodd, Ian C; Davies, William J; Wilkinson, Sally

    2013-10-01

    The mechanism of age-induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA- or soil drying-induced stomatal closure of older leaves was partly restored by pretreating plants with 1-methylcyclopropene (1-MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C-2, which contains 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water-use efficiency.

  19. EDTA Chelation Therapy to Reduce Cardiovascular Events in Persons with Diabetes.

    PubMed

    Ouyang, Pamela; Gottlieb, Sheldon H; Culotta, Valerie L; Navas-Acien, Ana

    2015-11-01

    The Trial to Assess Chelation Therapy (TACT) was a randomized double-blind placebo-controlled trial enrolling patients age ≥50 years with prior myocardial infarction. TACT used a 2 × 2 factorial design to study ethylene diamine tetraacetic acid (EDTA) chelation and high-dose vitamin supplementation. Chelation provided a modest but significant reduction in cardiovascular endpoints. The benefit was stronger and significant among participants with diabetes but absent in those without diabetes. Mechanisms by which chelation might reduce cardiovascular risk in persons with diabetes include the effects of EDTA chelation on transition and toxic metals. Transition metals, particularly copper and iron, play important roles in oxidative stress pathways. Toxic metals, in particular cadmium and lead, are toxic for the cardiovascular system. This review discusses the epidemiologic evidence and animal and human studies supporting the role of these metals in the development of diabetes and ischemic heart disease and potential ways by which EDTA chelation could confer cardiovascular benefit.

  20. Ethylene-Induced Inhibition of Root Growth Requires Abscisic Acid Function in Rice (Oryza sativa L.) Seedlings

    PubMed Central

    He, Si-Jie; Lu, Xiang; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2014-01-01

    Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-localized membrane protein homologous to Arabidopsis thaliana (Arabidopsis) ABA4, which is responsible for a branch of ABA biosynthesis. MHZ4 mutation reduced ABA level, but promoted ethylene production. Ethylene induced MHZ4 expression and promoted ABA accumulation in roots. MHZ4 overexpression resulted in enhanced and reduced ethylene response in roots and coleoptiles, respectively. In root, MHZ4-dependent ABA pathway acts at or downstream of ethylene receptors and positively regulates root ethylene response. This ethylene-ABA interaction mode is different from that reported in Arabidopsis, where ethylene-mediated root inhibition is independent of ABA function. In coleoptile, MHZ4-dependent ABA pathway acts at or upstream of OsEIN2 to negatively regulate coleoptile ethylene response, possibly by affecting OsEIN2 expression. At mature stage, mhz4 mutation affects branching and adventitious root formation on stem nodes of higher positions, as well as yield-related traits. Together, our findings reveal a novel mode of interplay between ethylene and ABA in control of rice growth and development. PMID:25330236

  1. Ethylene-induced inhibition of root growth requires abscisic acid function in rice (Oryza sativa L.) seedlings.

    PubMed

    Ma, Biao; Yin, Cui-Cui; He, Si-Jie; Lu, Xiang; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2014-10-01

    Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-localized membrane protein homologous to Arabidopsis thaliana (Arabidopsis) ABA4, which is responsible for a branch of ABA biosynthesis. MHZ4 mutation reduced ABA level, but promoted ethylene production. Ethylene induced MHZ4 expression and promoted ABA accumulation in roots. MHZ4 overexpression resulted in enhanced and reduced ethylene response in roots and coleoptiles, respectively. In root, MHZ4-dependent ABA pathway acts at or downstream of ethylene receptors and positively regulates root ethylene response. This ethylene-ABA interaction mode is different from that reported in Arabidopsis, where ethylene-mediated root inhibition is independent of ABA function. In coleoptile, MHZ4-dependent ABA pathway acts at or upstream of OsEIN2 to negatively regulate coleoptile ethylene response, possibly by affecting OsEIN2 expression. At mature stage, mhz4 mutation affects branching and adventitious root formation on stem nodes of higher positions, as well as yield-related traits. Together, our findings reveal a novel mode of interplay between ethylene and ABA in control of rice growth and development.

  2. EDTA redistribution of lead and cadmium into the soft tissues in a human with a high lead burden - should DMSA always be used to follow EDTA in such cases?

    PubMed

    Crinnion, Walter J

    2011-06-01

    Intravenous sodium calcium ethylene diamine tetra acetic acid (EDTA) and oral 2,3-dimercaptosuccinic acid (DMSA) have both been used to reduce the burden of lead in humans. Each of these agents enhances the mobilization of lead from different areas of the body - EDTA from the trabecular bone and DMSA from the soft tissue. A study of Korean battery workers revealed that EDTA appeared to increase the soft tissue burden of lead, resulting in increased levels of aminolevulinic acid and greater subsequent lead mobilization with DMSA. This case report discusses a patient with a higher-than-normal lead burden who exhibited increased tissue lead burden after intravenous EDTA. The elevated tissue burden of lead was still present, albeit lower, after five consecutive days of oral DMSA therapy. If this single case is representative of a typical human response to the use of intravenous (IV) EDTA for lead, then it suggests that all persons undergoing such treatment should be administered oral DMSA for a minimum of one week after EDTA treatment.

  3. The Ability of PAS, Acetylsalicylic Acid and Calcium Disodium EDTA to Protect Against the Toxic Effects of Manganese on Mitochondrial Respiration in Gill of Crassostrea virginica.

    PubMed

    Crawford, Sherine; Davis, Kiyya; Saddler, Claudette; Joseph, Jevaun; Catapane, Edward J; Carroll, Margaret A

    2011-01-01

    Manganese (Mn) is an essential metal that at excessive levels in brain causes Manganism, a condition similar to Parkinson's disease. Previously we showed that Mn had a neurotoxic effect on the dopaminergic, but not serotonergic, innervation of the lateral ciliated cells in the gill of the Eastern Oyster, Crassostrea virginica. While the mechanism of action of Mn toxicity is not completely understood, studies suggest that Mn toxicity may involve mitochondrial damage and resulting neural dysfunction in the brain's dopaminergic system. In this study we utilized micro-batch chambers and oxygen probes to measure oyster gill mitochondrial respiration in the presence of Mn and potential Mn blockers. The addition of Mn to respiring mitochondria caused a dose dependent decrease in mitochondrial O(2) consumption. Pretreating mitochondria with calcium disodium EDTA (caEDTA), p aminosalicylic acid (PAS) or acetylsalicylic acid (ASA) before Mn additions, provided full protection against the toxic effects of Mn. While mitochondrial pretreatment with any of the 3 drugs effectively blocked Mn toxicity, none of the drugs tested was able to reverse the decrease in mitochondrial O(2) consumption seen in Mn treated mitochondria. The study found that high levels of Mn had a toxic effect on gill mitochondrial O(2) consumption and that this effect could be blocked by the drugs caEDTA, PAS and ASA. C. virginica continues to be a good model with which to investigate the mechanism that underlies manganese neurotoxcity and in the pharmacological study of drugs to treat or prevent Manganism. PMID:21977482

  4. The Ability of PAS, Acetylsalicylic Acid and Calcium Disodium EDTA to Protect Against the Toxic Effects of Manganese on Mitochondrial Respiration in Gill of Crassostrea virginica

    PubMed Central

    Crawford, Sherine; Davis, Kiyya; Saddler, Claudette; Joseph, Jevaun; Catapane, Edward J.; Carroll, Margaret A.

    2011-01-01

    Manganese (Mn) is an essential metal that at excessive levels in brain causes Manganism, a condition similar to Parkinson's disease. Previously we showed that Mn had a neurotoxic effect on the dopaminergic, but not serotonergic, innervation of the lateral ciliated cells in the gill of the Eastern Oyster, Crassostrea virginica. While the mechanism of action of Mn toxicity is not completely understood, studies suggest that Mn toxicity may involve mitochondrial damage and resulting neural dysfunction in the brain’s dopaminergic system. In this study we utilized micro-batch chambers and oxygen probes to measure oyster gill mitochondrial respiration in the presence of Mn and potential Mn blockers. The addition of Mn to respiring mitochondria caused a dose dependent decrease in mitochondrial O2 consumption. Pretreating mitochondria with calcium disodium EDTA (caEDTA), p aminosalicylic acid (PAS) or acetylsalicylic acid (ASA) before Mn additions, provided full protection against the toxic effects of Mn. While mitochondrial pretreatment with any of the 3 drugs effectively blocked Mn toxicity, none of the drugs tested was able to reverse the decrease in mitochondrial O2 consumption seen in Mn treated mitochondria. The study found that high levels of Mn had a toxic effect on gill mitochondrial O2 consumption and that this effect could be blocked by the drugs caEDTA, PAS and ASA. C. virginica continues to be a good model with which to investigate the mechanism that underlies manganese neurotoxcity and in the pharmacological study of drugs to treat or prevent Manganism. PMID:21977482

  5. Regulation of Abscisic Acid Signaling by the Ethylene Response Pathway in Arabidopsis

    PubMed Central

    Ghassemian, Majid; Nambara, Eiji; Cutler, Sean; Kawaide, Hiroshi; Kamiya, Yuji; McCourt, Peter

    2000-01-01

    Although abscisic acid (ABA) is involved in a variety of plant growth and developmental processes, few genes that actually regulate the transduction of the ABA signal into a cellular response have been identified. In an attempt to determine negative regulators of ABA signaling, we identified mutants, designated enhanced response to ABA3 (era3), that increased the sensitivity of the seed to ABA. Biochemical and molecular analyses demonstrated that era3 mutants overaccumulate ABA, suggesting that era3 is a negative regulator of ABA synthesis. Subsequent genetic analysis of era3 alleles, however, showed that these are new alleles at the ETHYLENE INSENSITIVE2 locus. Other mutants defective in their response to ethylene also showed altered ABA sensitivity; from these results, we conclude that ethylene appears to be a negative regulator of ABA action during germination. In contrast, the ethylene response pathway positively regulates some aspects of ABA action that involve root growth in the absence of ethylene. We discuss the response of plants to ethylene and ABA in the context of how these two hormones could influence the same growth responses. PMID:10899978

  6. Effects of gibberellic Acid, calcium, kinetic, and ethylene on growth and cell wall composition of pea epicotyls.

    PubMed

    Mondal, M H

    1975-11-01

    The influence of gibberellic acid (GA), calcium, kinetin, and ethylene on growth and cell-wall composition of decapitated pea epicotyls (Pisum sativum L. var. Alaska) was investigated. Calcium, kinetin, and ethylene each caused an inhibition of GA-induced elongation of pea stems. Gibberellic acid did not reverse the induction of swelling by Ca(2+), kinetin, or ethylene. Both Ca(2+) and ethylene significantly inhibited the stimulatory effects of GA on the formation of residual wall material. Although GA promoted the development of walls relatively low in pectic substances and pectic uronic acid, Ca(2+), kinetin, and ethylene favored the formation of walls rich in these constituents. Calcium, kinetin, and GA, alone or in combination, had no effect on the production of ethylene by pea epicotyls. PMID:16659357

  7. A model for hot tack behavior in ethylene acid copolymer films

    SciTech Connect

    Shekhar, A. )

    1994-01-01

    A model has been developed for hot tack behavior in ethylene methacrylic acid and ethylene acrylic acid copolymers based on statistical regression of data. This model shows trends and provides insights on the factors that influence hot tack strength. A correlation of eight independent variables with hot tack strength showed that the two factors with the greatest impact on hot tack strength are seal temperature and acid content of the film. The melt indices, melt point temperatures, and synthesis temperatures of the film resin had insignificant correlations with hot tack. No significant difference in hot tack strength was found between acrylic and methacrylic acid copolymers. This model provides a better understanding of an important phenomenon in packaging applications, and it can be used to approximate hot tack behavior in acid copolymers when certain variables are specified.

  8. 1-aminocyclopropane-1-carboxylic acid (ACC) in plants: more than just the precursor of ethylene!

    PubMed Central

    Van de Poel, Bram; Van Der Straeten, Dominique

    2014-01-01

    Ethylene is a simple two carbon atom molecule with profound effects on plants. There are quite a few review papers covering all aspects of ethylene biology in plants, including its biosynthesis, signaling and physiology. This is merely a logical consequence of the fascinating and pleiotropic nature of this gaseous plant hormone. Its biochemical precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) is also a fairly simple molecule, but perhaps its role in plant biology is seriously underestimated. This triangularly shaped amino acid has many more features than just being the precursor of the lead-role player ethylene. For example, ACC can be conjugated to three different derivatives, but their biological role remains vague. ACC can also be metabolized by bacteria using ACC-deaminase, favoring plant growth and lowering stress susceptibility. ACC is also subjected to a sophisticated transport mechanism to ensure local and long-distance ethylene responses. Last but not least, there are now a few exciting studies where ACC has been reported to function as a signal itself, independently from ethylene. This review puts ACC in the spotlight, not to give it the lead-role, but to create a picture of the stunning co-production of the hormone and its precursor. PMID:25426135

  9. EDTA-dependent pseudothrombocytopenia in a child.

    PubMed

    Akbayram, Sinan; Dogan, Murat; Akgun, Cihangir; Caksen, Hüseyin; Oner, Ahmet Faik

    2011-10-01

    Ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia (PTCP) is the phenomenon of a spurious low platelet count due to antiplatelet antibodies that cause platelet clumping in blood anticoagulated with EDTA. The aggregation of platelets in EDTA-dependent PTCP is usually prevented by other anticoagulants, such as sodium citrate or heparin. EDTA-dependent PTCP has never been associated with hemorrhagic diathesis or platelet dysfunction. In this article, a 10-year-old boy with EDTA- and heparin-dependent PTCP is presented because of rare presentation. We report that EDTA and heparin can induce platelet clumping, and thus spuriously low platelet counts. However, aggregation of platelets was not detected in blood samples with sodium citrate, and platelet count was normal. PMID:20530050

  10. The implementation of high fermentative 2,3-butanediol production from xylose by simultaneous additions of yeast extract, Na2EDTA, and acetic acid.

    PubMed

    Wang, Xiao-Xiong; Hu, Hong-Ying; Liu, De-Hua; Song, Yuan-Quan

    2016-01-25

    The effective use of xylose may significantly enhance the feasibility of using lignocellulosic hydrolysate to produce 2,3-butanediol (2,3-BD). Previous difficulties in 2,3-BD production include that the high-concentration xylose cannot be converted completely and the fermentation rate is slow. This study investigated the effects of yeast extract, ethylenediaminetetraacetic acid disodium salt (Na2EDTA), and acetic acid on 2,3-BD production from xylose. The central composite design approach was used to optimize the concentrations of these components. It was found that simultaneous addition of yeast extract, Na2EDTA, and acetic acid could significantly improve 2,3-BD production. The optimal concentrations of yeast extract, Na2EDTA, and acetic acid were 35.2, 1.2, and 4.5 g/L, respectively. The 2,3-BD concentration in the optimized medium reached 39.7 g/L after 48 hours of shake flask fermentation, the highest value ever reported in such a short period. The xylose utilization ratio and the 2,3-BD concentration increased to 99.0% and 42.7 g/L, respectively, after 48 hours of stirred batch fermentation. Furthermore, the 2,3-BD yield was 0.475 g/g, 95.0% of the theoretical maximum value. As the major components of lignocellulosic hydrolysate are glucose, xylose, and acetic acid, the results of this study indicate the possibility of directly using the hydrolysate to effectively produce 2,3-BD.

  11. Removal of arsenic and cadmium with sequential soil washing techniques using Na2EDTA, oxalic and phosphoric acid: Optimization conditions, removal effectiveness and ecological risks.

    PubMed

    Wei, Meng; Chen, Jiajun; Wang, Xingwei

    2016-08-01

    Testing of sequential soil washing in triplicate using typical chelating agent (Na2EDTA), organic acid (oxalic acid) and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated by heavy metals close to a mining area. The aim of the testing was to improve removal efficiency and reduce mobility of heavy metals. The sequential extraction procedure and further speciation analysis of heavy metals demonstrated that the primary components of arsenic and cadmium in the soil were residual As (O-As) and exchangeable fraction, which accounted for 60% and 70% of total arsenic and cadmium, respectively. It was determined that soil washing agents and their washing order were critical to removal efficiencies of metal fractions, metal bioavailability and potential mobility due to different levels of dissolution of residual fractions and inter-transformation of metal fractions. The optimal soil washing option for arsenic and cadmium was identified as phosphoric-oxalic acid-Na2EDTA sequence (POE) based on the high removal efficiency (41.9% for arsenic and 89.6% for cadmium) and the minimal harmful effects of the mobility and bioavailability of the remaining heavy metals.

  12. Removal of arsenic and cadmium with sequential soil washing techniques using Na2EDTA, oxalic and phosphoric acid: Optimization conditions, removal effectiveness and ecological risks.

    PubMed

    Wei, Meng; Chen, Jiajun; Wang, Xingwei

    2016-08-01

    Testing of sequential soil washing in triplicate using typical chelating agent (Na2EDTA), organic acid (oxalic acid) and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated by heavy metals close to a mining area. The aim of the testing was to improve removal efficiency and reduce mobility of heavy metals. The sequential extraction procedure and further speciation analysis of heavy metals demonstrated that the primary components of arsenic and cadmium in the soil were residual As (O-As) and exchangeable fraction, which accounted for 60% and 70% of total arsenic and cadmium, respectively. It was determined that soil washing agents and their washing order were critical to removal efficiencies of metal fractions, metal bioavailability and potential mobility due to different levels of dissolution of residual fractions and inter-transformation of metal fractions. The optimal soil washing option for arsenic and cadmium was identified as phosphoric-oxalic acid-Na2EDTA sequence (POE) based on the high removal efficiency (41.9% for arsenic and 89.6% for cadmium) and the minimal harmful effects of the mobility and bioavailability of the remaining heavy metals. PMID:27179243

  13. EDTA disodium zinc has superior bioavailability compared to common inorganic or chelated zinc compounds in rats fed a high phytic acid diet.

    PubMed

    Bertinato, Jesse; Sherrard, Lindsey; Plouffe, Louise J

    2012-10-01

    Different zinc (Zn) compounds have unique properties that may influence the amount of Zn absorbed particularly in the presence of phytic acid (PA), a common food component that binds Zn and decreases its bioavailability. In this study, 30-day-old male rats (n=12/diet group) were fed diets supplemented with PA (0.8%) and low levels (8mg Zn/kg diet) of inorganic (Zn oxide, Zn sulphate) or chelated (Zn gluconate, Zn acetate, Zn citrate, EDTA disodium Zn, Zn orotate) Zn compounds for 5 weeks. Two control groups were fed diets supplemented with low or normal (30mg Zn/kg diet) Zn (as Zn oxide) without added PA. Control rats fed the low Zn oxide diet showed depressed Zn status. Addition of PA to this diet exacerbated the Zn deficiency in rats. Growth (body weight gain and femur length) and Zn concentrations in plasma and tissues were similar in rats fed Zn oxide, Zn sulphate, Zn gluconate, Zn acetate, Zn citrate or Zn orotate. Rats fed EDTA disodium Zn showed enhanced growth compared to rats fed Zn oxide or Zn gluconate and had higher Zn concentrations in plasma and femur compared to rats fed all other Zn compounds. Only the haematological profile of rats fed EDTA disodium Zn did not differ from control rats fed normal Zn. These data indicate that in rats fed a high PA diet, bioavailability of commonly used inorganic or chelated Zn compounds does not differ appreciably, but Zn supplied as an EDTA disodium salt has superior bioavailability.

  14. Competitive removal of Cu-EDTA and Ni-EDTA via microwave-enhanced Fenton oxidation with hydroxide precipitation.

    PubMed

    Lin, Qintie; Pan, Hanping; Yao, Kun; Pan, Yonggang; Long, Wei

    2015-01-01

    Ethylenediaminetetraacetic acid (EDTA) can form very stable complexes with heavy metal ions, greatly inhibiting conventional metal-removal technologies used in water treatment. Both the oxidation of EDTA and the reduction of metal ions in metal-EDTA systems via the microwave-enhanced Fenton reaction followed by hydroxide precipitation were investigated. The Cu(II)-Ni(II)-EDTA, Cu(II)-EDTA and Ni(II)-EDTA exhibited widely different decomplexation efficiencies under equivalent conditions. When the reaction reached equilibrium, the chemical oxygen demand was reduced by a microwave-enhanced Fenton reaction in different systems and the reduction order from high to low was Cu(II)-Ni(II)-EDTA ≈ Cu(II)-EDTA > Ni(II)-EDTA. The removal efficiencies of both Cu(2+) and Ni(2+) in Cu-Ni-EDTA wastewaters were much higher than those in a single heavy metal system. The degradation efficiency of EDTA in Cu-Ni-EDTA was lower than that in a single metal system. In the Cu-Ni-EDTA system, the microwave thermal degradation and the Fenton-like reaction created by Cu catalyzed H2O2 altered the EDTA degradation pathway and increased the pH of the wastewater system, conversely inhibiting residual EDTA degradation. PMID:26398034

  15. Competitive removal of Cu-EDTA and Ni-EDTA via microwave-enhanced Fenton oxidation with hydroxide precipitation.

    PubMed

    Lin, Qintie; Pan, Hanping; Yao, Kun; Pan, Yonggang; Long, Wei

    2015-01-01

    Ethylenediaminetetraacetic acid (EDTA) can form very stable complexes with heavy metal ions, greatly inhibiting conventional metal-removal technologies used in water treatment. Both the oxidation of EDTA and the reduction of metal ions in metal-EDTA systems via the microwave-enhanced Fenton reaction followed by hydroxide precipitation were investigated. The Cu(II)-Ni(II)-EDTA, Cu(II)-EDTA and Ni(II)-EDTA exhibited widely different decomplexation efficiencies under equivalent conditions. When the reaction reached equilibrium, the chemical oxygen demand was reduced by a microwave-enhanced Fenton reaction in different systems and the reduction order from high to low was Cu(II)-Ni(II)-EDTA ≈ Cu(II)-EDTA > Ni(II)-EDTA. The removal efficiencies of both Cu(2+) and Ni(2+) in Cu-Ni-EDTA wastewaters were much higher than those in a single heavy metal system. The degradation efficiency of EDTA in Cu-Ni-EDTA was lower than that in a single metal system. In the Cu-Ni-EDTA system, the microwave thermal degradation and the Fenton-like reaction created by Cu catalyzed H2O2 altered the EDTA degradation pathway and increased the pH of the wastewater system, conversely inhibiting residual EDTA degradation.

  16. Photodynamic therapy of human skin tumors using topical application of 5-aminolevulinic acid, dimethylsulfoxide (DMSO), and edetic acid disodium salt (EDTA)

    NASA Astrophysics Data System (ADS)

    Orenstein, Arie; Kostenich, Gennady; Tsur, H.; Roitman, Leonid; Ehrenberg, Benjamin; Malik, Zvi

    1995-01-01

    The results of photodynamic therapy (PDT) in 48 patients bearing basal cell carcinoma (BCC) and 7 patients with squamous cell carcinoma (SCC) of the skin are described. Five- aminolevulinic acid (5-ALA) was applied topically in two formulations. The first formulation contained 20% of 5-ALA in a base cream, and the second formulation (5-ALA composite cream), contained an additional 2% of dimethylsulfoxide (DMSO) and 2% of edetic acid disodium salt (EDTA). The creams were left on the skin for 2 - 5 hours. Production of protoporphyrin (PP) was measured in situ by a laser-induced fluorescence (LIF) method. The results of fluorescence measurement clearly indicate that PP accumulation in tumors induced by the 5-ALA composite cream was markedly higher than that induced by the 5-ALA cream. The tumors were light-irradiated (600 - 720 nm) after 4 - 5 hours of cream applications, using the light delivery system Versa-Light by a light dose of 100 J/cm2. The clinically superficial BCC tumors were highly responsive to PDT; the overall result in BCC patients was an 85.4% complete response. Histological examination showed an initial edematous reaction, followed by necrosis and complete disappearance of the tumor. The superficial SCC tumors showed a 100% complete response after PDT. The ulcerated nodular SCC showed partial responses.

  17. Effect of Ethylene on Cell Division and Deoxyribonucleic Acid Synthesis in Pisum sativum1

    PubMed Central

    Apelbaum, Akiva; Burg, Stanley P.

    1972-01-01

    Ethylene and supraoptimal levels of 2,4-dichlorophenoxyacetic acid inhibit the growth of the apical hook region of etiolated Pisum sativum (var. Alaska) seedlings by stopping almost all cell divisions. Cells are prevented from entering prophase. The hormones also retard cell division in intact root tips and completely stop the process in lateral buds. The latter inhibition is reversed partially by benzyl adenine. In root tips and the stem plumular and subhook regions, ethylene inhibits DNA synthesis. The magnitude of this inhibition is correlated with the degree of repression of cell division in meristematic tissue, suggesting that the effect on cell division results from a lack of DNA synthesis. Ethylene inhibits cell division within a few hours with a dose-response curve similar to that for most other actions of the gas. Experiments with seedlings grown under hypobaric conditions suggest that the gas naturally controls plumular expansion and cell division in the apical region. Images PMID:16658105

  18. Redistribution of fractions of zinc, cadmium, nickel, copper, and lead in contaminated calcareous soils treated with EDTA.

    PubMed

    Jalali, Mohsen; Khanlari, Zahra V

    2007-11-01

    Effect of ethylene diamine tetraacetic acid (EDTA) on the fractionation of zinc (Zn), cadmium (Cd), nickel (Ni), copper (Cu), and lead (Pb) in contaminated calcareous soils was investigated. Soil samples containing variable levels of contamination, from 105.9 to 5803 mg/kg Zn, from 2.2 to 1361 mg/kg Cd, from 31 to 64.0 mg/kg Ni, from 24 to 84 mg/kg Cu, and from 109 to 24,850 mg/kg Pb, were subjected to EDTA treatment at different dosages of 0, 1.0, and 2.0 g/kg. Metals in the incubated soils were fractionated after 5 months by a sequential extraction procedure, in which the metal fractions were experimentally defined as exchangeable (EXCH), carbonate (CARB), Mn oxide (MNO), Fe oxide (FEO), organic matter (OM), and residual (RES) fractions. In contaminated soils without EDTA addition, Zn, Ni, Cu, and Pb were predominately present in the RES fraction, up to 60.0%, 32.3%, 41.1%, and 36.8%, respectively. In general, with the EDTA addition, the EXCH and CARB fractions of these metals increased dramatically while the OM fraction decreased. The Zn, Ni, Cu, and Pb were distributed mostly in RES, OM, FEO, and CARB fractions in contaminated soils, but Cd was found predominately in the CARB, MNO, and RES fractions. The OM fraction decreased with increasing amounts of EDTA. In the contaminated soils, EDTA removed some Pb, Zn, Cu, and Ni from MNO, FEO, and OM fractions and redistributed them into CARB and EXCH fractions. Based on the relative percent in the EXCH and CARB fractions, the order of solubility was Cd > Pb > Ni > Cu > Zn for contaminated soils, before adding of EDTA, and after adding of EDTA, the order of solubility was Pb > Cd > Zn > Ni > Cu. The risk of groundwater contamination will increase after applying EDTA and it needed to be used very carefully.

  19. To grow old: regulatory role of ethylene and jasmonic acid in senescence

    PubMed Central

    Kim, Joonyup; Chang, Caren; Tucker, Mark L.

    2015-01-01

    Senescence, the final stage in the development of an organ or whole plant, is a genetically programmed process controlled by developmental and environmental signals. Age-related signals underlie the onset of senescence in specific organs (leaf, flower, and fruit) as well as the whole plant (monocarpic senescence). Rudimentary to most senescence processes is the plant hormone ethylene, a small gaseous molecule critical to diverse processes throughout the life of the plant. The role of ethylene in senescence was discovered almost 100 years ago, but the molecular mechanisms by which ethylene regulates senescence have been deciphered more recently primarily through genetic and molecular studies in Arabidopsis. Jasmonic acid (JA), another plant hormone, is emerging as a key player in the control of senescence. The regulatory network of ethylene and JA involves the integration of transcription factors, microRNAs, and other hormones. In this review, we summarize the current understanding of ethylene’s role in senescence, and discuss the interplay of ethylene with JA in the regulation of senescence. PMID:25688252

  20. The EDTA Amendment in Phytoextraction of (134)Cs From Soil by Indian Mustard (Brassica juncea).

    PubMed

    Tjahaja, Poppy Intan; Sukmabuana, Putu; Roosmini, Dwina

    2015-01-01

    Soil contamination with radiocaesium is a significant problem at any countries when a nuclear accident occurred. Recently, phytoextraction technique is developed to remediate the contaminated environment. However, the application is limited by the availability of the contaminant for root uptake. Therefore, a green house trial experiment of soil amendment with ethylene diamine tetraacetic acid (EDTA) has been conducted to examine (134)Cs availability for root uptake. Two groups of Indian mustard (Brassica juncea) were cultivated in (134)Cs contaminated soil. The soil in the first group was treated with EDTA amendment, while the other was not. Plant growth was observed gravimetrically and the (134)Cs concentration in soil as well as plants were determined using gamma spectrometry. The plant uptake capacity was determined as transfer factor (Fv), and the Fv values of 0.22 ± 0.0786 and 0.12 ± 0.039 were obtained for the soil treated with and without EDTA amendment, respectively. The phytoextraction efficiency of the plant cultivated in (134)Cs contaminated soil both with and without EDTA amendment was low. The EDTA amendment to the soil seems to enhance the (134)Cs availability for root uptake of Indian mustard and can still be considered to assist the field phytoremediation of contaminated soil.

  1. The EDTA Amendment in Phytoextraction of (134)Cs From Soil by Indian Mustard (Brassica juncea).

    PubMed

    Tjahaja, Poppy Intan; Sukmabuana, Putu; Roosmini, Dwina

    2015-01-01

    Soil contamination with radiocaesium is a significant problem at any countries when a nuclear accident occurred. Recently, phytoextraction technique is developed to remediate the contaminated environment. However, the application is limited by the availability of the contaminant for root uptake. Therefore, a green house trial experiment of soil amendment with ethylene diamine tetraacetic acid (EDTA) has been conducted to examine (134)Cs availability for root uptake. Two groups of Indian mustard (Brassica juncea) were cultivated in (134)Cs contaminated soil. The soil in the first group was treated with EDTA amendment, while the other was not. Plant growth was observed gravimetrically and the (134)Cs concentration in soil as well as plants were determined using gamma spectrometry. The plant uptake capacity was determined as transfer factor (Fv), and the Fv values of 0.22 ± 0.0786 and 0.12 ± 0.039 were obtained for the soil treated with and without EDTA amendment, respectively. The phytoextraction efficiency of the plant cultivated in (134)Cs contaminated soil both with and without EDTA amendment was low. The EDTA amendment to the soil seems to enhance the (134)Cs availability for root uptake of Indian mustard and can still be considered to assist the field phytoremediation of contaminated soil. PMID:26208541

  2. Thermosensitivity of bile acid-based oligo(ethylene glycol) stars in aqueous solutions.

    PubMed

    Strandman, Satu; Le Dévédec, Frantz; Zhu, X X

    2011-08-01

    Amphiphilic star-shaped oligo(ethylene glycol)s with a hydrophobic bile acid core and varying number of hydrophilic arms have been made. Their thermal behavior in aqueous solutions depends on the number rather than the length of the arms. The two-armed lithocholate derivative showed the strongest tendency for association and exhibited the lowest cloud point (79 °C) of the oligomers made, as well as another phase separation at a lower temperature (31 °C). The "double thermosensitivity" arising both from the salt-dependent LCST of the oligo(ethylene glycol) segments and the temperature-responsive self-assembly of amphiphilic bile acid derivative provides an interesting path in the design of bile acid-based smart materials.

  3. Thermosensitivity of bile acid-based oligo(ethylene glycol) stars in aqueous solutions.

    PubMed

    Strandman, Satu; Le Dévédec, Frantz; Zhu, X X

    2011-08-01

    Amphiphilic star-shaped oligo(ethylene glycol)s with a hydrophobic bile acid core and varying number of hydrophilic arms have been made. Their thermal behavior in aqueous solutions depends on the number rather than the length of the arms. The two-armed lithocholate derivative showed the strongest tendency for association and exhibited the lowest cloud point (79 °C) of the oligomers made, as well as another phase separation at a lower temperature (31 °C). The "double thermosensitivity" arising both from the salt-dependent LCST of the oligo(ethylene glycol) segments and the temperature-responsive self-assembly of amphiphilic bile acid derivative provides an interesting path in the design of bile acid-based smart materials. PMID:21661073

  4. Fe(III)EDTA and Fe(II)EDTA-NO reduction by a sulfate reducing bacterium in NO and SO₂ scrubbing liquor.

    PubMed

    Chen, Mingxiang; Zhou, Jiti; Zhang, Yu; Wang, Xiaojun; Shi, Zhuang; Wang, Xiaowei

    2015-03-01

    A viable process concept, based on NO and SO2 absorption into an alkaline Fe(II)EDTA (EDTA: ethylenediaminetetraacetic acid) solution in a scrubber combined with biological reduction of the absorbed SO2 utilizing sulfate reducing bacteria (SRB) and regeneration of the scrubbing liquor in a single bioreactor, was developed. The SRB, Desulfovibrio sp. CMX, was used and its sulfate reduction performances in FeEDTA solutions and Fe(II)EDTA-NO had been investigated. In this study, the detailed regeneration process of Fe(II)EDTA solution, which contained Fe(III)EDTA and Fe(II)EDTA-NO reduction processes in presence of D. sp. CMX and sulfate, was evaluated. Fe(III)EDTA and Fe(II)EDTA-NO reduction processes were primarily biological, even if Fe(III)EDTA and Fe(II)EDTA-NO could also be chemically convert to Fe(II)EDTA by biogenic sulfide. Regardless presence or absence of sulfate, more than 87 % Fe(III)EDTA and 98 % Fe(II)EDTA-NO were reduced in 46 h, respectively. Sulfate and Fe(III)EDTA had no affection on Fe(II)EDTA-NO reduction. Sulfate enhanced final Fe(III)EDTA reduction. Effect of Fe(III)EDTA on Fe(II)EDTA-NO reduction rate was more obvious than effect of sulfate on Fe(II)EDTA-NO reduction rate before 8 h. To overcome toxicity of Fe(II)EDTA-NO on SRB, Fe(II)EDTA-NO was reduced first and the reduction of Fe(III)EDTA and sulfate occurred after 2 h. First-order Fe(II)EDTA-NO reduction rate and zero-order Fe(III)EDTA reduction rate were detected respectively before 8 h.

  5. Treatment of waste containing EDTA by chemical oxidation

    SciTech Connect

    Tucker, M.D.; Barton, L.L.; Thomson, B.M.; Wagener, B.M.; Aragon, A.

    1999-07-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been extensively used to enhance the solubilization of heavy metal cations and release of EDTA contributes to environmental problems. EDTA is recalcitrant to microbial metabolism and chemical oxidation is considered a possible method of remedial treatment. The use of the commercially available process of MIOX Corporation generates mixed oxidants on site and this solution is markedly effective in the destruction of the chelating characteristic and the decarboxylation of EDTA. When measuring the release of C-14 from carboxyl labeled EDTA, the mixed oxidant solution was comparable to the Fenton's reaction over a broad pH range. The presence of Mn{sup 2+}, Cr{sup 3+}, or Fe{sup 3+} at levels equal to that of EDTA stimulated the rate of EDTA decomposition; however, the rate of EDTA breakdown was inhibited when the concentration of Cr{sup 3+} or Mn{sup 2+} exceeded the concentration of EDTA. The treatment of Co{sup 2+} -EDTA or Cu{sup 2+} -EDTA with mixed oxidants in the presence of ultra violet light resulted in the loss of chelation ability of EDTA. In the absence of chelated metals, over 75% of the chelation property of a 70 nM EDTA solution was destroyed in 45 min. The reaction products resulting from the use of mixed oxidants added to EDTA were non-toxic to bacteria and should not contribute to additional environmental problems.

  6. Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard.

    PubMed

    Masood, Asim; Khan, M Iqbal R; Fatma, Mehar; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

    2016-07-01

    The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg(-1) soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg(-1) soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants. PMID:26998941

  7. Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard.

    PubMed

    Masood, Asim; Khan, M Iqbal R; Fatma, Mehar; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

    2016-07-01

    The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg(-1) soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg(-1) soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants.

  8. Abscisic Acid Antagonizes Ethylene Production through the ABI4-Mediated Transcriptional Repression of ACS4 and ACS8 in Arabidopsis.

    PubMed

    Dong, Zhijun; Yu, Yanwen; Li, Shenghui; Wang, Juan; Tang, Saijun; Huang, Rongfeng

    2016-01-01

    Increasing evidence has revealed that abscisic acid (ABA) negatively modulates ethylene biosynthesis, although the underlying mechanism remains unclear. To identify the factors involved, we conducted a screen for ABA-insensitive mutants with altered ethylene production in Arabidopsis. A dominant allele of ABI4, abi4-152, which produces a putative protein with a 16-amino-acid truncation at the C-terminus of ABI4, reduces ethylene production. By contrast, two recessive knockout alleles of ABI4, abi4-102 and abi4-103, result in increased ethylene evolution, indicating that ABI4 negatively regulates ethylene production. Further analyses showed that expression of the ethylene biosynthesis genes ACS4, ACS8, and ACO2 was significantly decreased in abi4-152 but increased in the knockout mutants, with partial dependence on ABA. Chromatin immunoprecipitation-quantitative PCR assays showed that ABI4 directly binds the promoters of these ethylene biosynthesis genes and that ABA enhances this interaction. A fusion protein containing the truncated ABI4-152 peptide accumulated to higher levels than its full-length counterpart in transgenic plants, suggesting that ABI4 is destabilized by its C terminus. Therefore, our results demonstrate that ABA negatively regulates ethylene production through ABI4-mediated transcriptional repression of the ethylene biosynthesis genes ACS4 and ACS8 in Arabidopsis.

  9. Effect of enzyme secreting bacterial pretreatment on enhancement of aerobic digestion potential of waste activated sludge interceded through EDTA.

    PubMed

    Kavitha, S; Adish Kumar, S; Yogalakshmi, K N; Kaliappan, S; Rajesh Banu, J

    2013-12-01

    In this study, the effect of Ethylene diamine tetra acetic acid (EDTA) on Extracellular polymeric substance (EPS) removal tailed with bacterial enzymatic pretreatment on aerobic digestion of activated sludge was studied. In order to enhance the accessibility of sludge to the enzyme secreting bacteria; the extracellular polymeric substances were removed using EDTA. EDTA efficiently removed the EPS with limited cell lysis and enhanced the sludge enzyme activity at its lower concentration of 0.2 g/g SS. The sludge was then subjected to bacterial pretreatment to enhance the aerobic digestion. In aerobic digestion the best results in terms of Suspended solids (SS) reduction (48.5%) and COD (Chemical oxygen demand) solubilization (47.3%) was obtained in experimental reactor than in control. These results imply that aerobic digestion can be enhanced efficiently through bacterial pretreatment of EPS removed sludge.

  10. Ethylene and jasmonic acid act as negative modulators during mutualistic symbiosis between Laccaria bicolor and Populus roots.

    PubMed

    Plett, Jonathan M; Khachane, Amit; Ouassou, Malika; Sundberg, Björn; Kohler, Annegret; Martin, Francis

    2014-04-01

    The plant hormones ethylene, jasmonic acid and salicylic acid have interconnecting roles during the response of plant tissues to mutualistic and pathogenic symbionts. We used morphological studies of transgenic- or hormone-treated Populus roots as well as whole-genome oligoarrays to examine how these hormones affect root colonization by the mutualistic ectomycorrhizal fungus Laccaria bicolor S238N. We found that genes regulated by ethylene, jasmonic acid and salicylic acid were regulated in the late stages of the interaction between L. bicolor and poplar. Both ethylene and jasmonic acid treatments were found to impede fungal colonization of roots, and this effect was correlated to an increase in the expression of certain transcription factors (e.g. ETHYLENE RESPONSE FACTOR1) and a decrease in the expression of genes associated with microbial perception and cell wall modification. Further, we found that ethylene and jasmonic acid showed extensive transcriptional cross-talk, cross-talk that was opposed by salicylic acid signaling. We conclude that ethylene and jasmonic acid pathways are induced late in the colonization of root tissues in order to limit fungal growth within roots. This induction is probably an adaptive response by the plant such that its growth and vigor are not compromised by the fungus. PMID:24383411

  11. Potentiometry: A Chromium (III) -- EDTA Complex

    ERIC Educational Resources Information Center

    Hoppe, J. I.; Howell, P. J.

    1975-01-01

    Describes an experiment that involves the preparation of a chromium (III)-EDTA compound, a study of its infrared spectrum, and the potentiometric determination of two successive acid dissociation constants. (Author/GS)

  12. Reciprocity between abscisic acid and ethylene at the onset of berry ripening and after harvest

    PubMed Central

    2010-01-01

    Background The ripening of grape berry is generally regulated by abscisic acid (ABA), and has no relationship with ethylene function. However, functional interaction and synergism between ABA and ethylene during the beginning of grape berry ripening (véraison) has been found recently. Results The expressions of VvNCED1 encoding 9-cis-epoxycarotenoid dioxygenase (NCED) and VvGT encoding ABA glucosyltransferase were all increased rapidly at the stage of véraison and reached the highest level at 9th week after full bloom. However, VvCYP1 encoding ABA 8'-hydroxylase and VvβG1 encoding berry β-glucosidase are different, whose expression peak appeared at the 10th week after full bloom and in especial VvβG1 remained at a high level till harvest. The VvACO1 encoding 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase, the VvETR2 (ethylene response 2) and VvCTR1 (constitutive triple response 1) had a transient expression peak at pre-véraison, while the VvEIN4 (ethylene insensitive 4) expression gradually increased from the véraison to one week before harvest stage. The above mentioned changes happened again in the berry after harvest. At one week before véraison, double block treatment with NiCl2 plus 1-methylcyclopropene (1-MCP) not only inhibited the release of ethylene and the expression of related genes but also suppressed the transcription of VvNCED1 and the synthesis of ABA which all might result in inhibiting the fruit ripening onset. Treatment with ABA could relieve the double block and restore fruit ripening course. However, after harvest, double block treatment with NiCl2 plus 1-MCP could not suppress the transcription of VvNCED1 and the accumulation of ABA, and also could not inhibit the start of fruit senescence. Conclusion The trace endogenous ethylene induces the transcription of VvNCED1 and then the generation of ABA followed. Both ethylene and ABA are likely to be important and their interplaying may be required to start the process of berry ripening

  13. Reactive oxygen species, abscisic acid and ethylene interact to regulate sunflower seed germination.

    PubMed

    El-Maarouf-Bouteau, Hayat; Sajjad, Yasar; Bazin, Jérémie; Langlade, Nicolas; Cristescu, Simona M; Balzergue, Sandrine; Baudouin, Emmanuel; Bailly, Christophe

    2015-02-01

    Sunflower (Helianthus annuus L.) seed dormancy is regulated by reactive oxygen species (ROS) and can be alleviated by incubating dormant embryos in the presence of methylviologen (MV), a ROS-generating compound. Ethylene alleviates sunflower seed dormancy whereas abscisic acid (ABA) represses germination. The purposes of this study were to identify the molecular basis of ROS effect on seed germination and to investigate their possible relationship with hormone signalling pathways. Ethylene treatment provoked ROS generation in embryonic axis whereas ABA had no effect on their production. The beneficial effect of ethylene on germination was lowered in the presence of antioxidant compounds, and MV suppressed the inhibitory effect of ABA. MV treatment did not alter significantly ethylene nor ABA production during seed imbibition. Microarray analysis showed that MV treatment triggered differential expression of 120 probe sets (59 more abundant and 61 less abundant genes), and most of the identified transcripts were related to cell signalling components. Many transcripts less represented in MV-treated seeds were involved in ABA signalling, thus suggesting an interaction between ROS and ABA signalling pathways at the transcriptional level. Altogether, these results shed new light on the crosstalk between ROS and plant hormones in seed germination.

  14. Synthesis and characterization of hydrolytically degradable copolyester biomaterials based on glycolic acid, sebacic acid and ethylene glycol.

    PubMed

    Simitzis, J; Soulis, S; Triantou, D; Zoumpoulakis, L; Zotali, P

    2011-12-01

    Copolyesters of glycolic acid (G) combined with sebacic acid (S) and ethylene glycol were synthesized in different molar ratios (G: 0-100% and S: 100-0%) and their hydrolytic degradation was studied and correlated with their structures. Based on the FTIR spectra of the homopolyesters and copolyesters and the normalized peak intensity of the I(2918), I(2848) and I(1087) for the corresponding wavenumbers, it is concluded that the I(2918) and the I(2848) are in accordance with the mean number degree of polymerization of ethylene sebacate units and the I(1087) is in accordance with the mean number degree of polymerization of glycolate units. Based on the XRD diffractograms, poly(ethylene sebacate) and poly(glycolic acid) belong to the monoclinic and the orthorhombic crystal system, respectively and both have higher crystallinity than the copolyesters. The experimental data of the hydrolytic degradation were fitted with exponential rise to maximum type functions using two-parameter model and four-parameter model. Three regions can been distinguished for the hydrolytic degradation by decreasing the molar feed ratio of sebacic acid, which are correlated with the changes of crystallinity. Two copolyesters are proposed: first the copolyester with high amount of glycolate units (S10G90) having higher hydrolytic degradation than G100 and second the copolyester with equal amount of glycolate and ethylene sebacate units (S50G50), having lower hydrolytic degradation than G100. These hydrolytically degradable copolyesters are soluble in common organic solvents, opposite to poly(glycolic acid) and could have perspectives for biomedical applications.

  15. Ethylene interacts with abscisic acid to regulate endosperm rupture during germination: a comparative approach using Lepidium sativum and Arabidopsis thaliana.

    PubMed

    Linkies, Ada; Müller, Kerstin; Morris, Karl; Turecková, Veronika; Wenk, Meike; Cadman, Cassandra S C; Corbineau, Françoise; Strnad, Miroslav; Lynn, James R; Finch-Savage, William E; Leubner-Metzger, Gerhard

    2009-12-01

    The micropylar endosperm cap covering the radicle in the mature seeds of most angiosperms acts as a constraint that regulates seed germination. Here, we report on a comparative seed biology study with the close Brassicaceae relatives Lepidium sativum and Arabidopsis thaliana showing that ethylene biosynthesis and signaling regulate seed germination by a mechanism that requires the coordinated action of the radicle and the endosperm cap. The larger seed size of Lepidium allows direct tissue-specific biomechanical, biochemical, and transcriptome analyses. We show that ethylene promotes endosperm cap weakening of Lepidium and endosperm rupture of both species and that it counteracts the inhibitory action of abscisic acid (ABA) on these two processes. Cross-species microarrays of the Lepidium micropylar endosperm cap and the radicle show that the ethylene-ABA antagonism involves both tissues and has the micropylar endosperm cap as a major target. Ethylene counteracts the ABA-induced inhibition without affecting seed ABA levels. The Arabidopsis loss-of-function mutants ACC oxidase2 (aco2; ethylene biosynthesis) and constitutive triple response1 (ethylene signaling) are impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germination. Ethylene production by the ACC oxidase orthologs Lepidium ACO2 and Arabidopsis ACO2 appears to be a key regulatory step. Endosperm cap weakening and rupture are promoted by ethylene and inhibited by ABA to regulate germination in a process conserved across the Brassicaceae.

  16. Poly(N-vinylimidazole/ethylene glycol dimethacrylate) for the purification and isolation of phenolic acids.

    PubMed

    Schemeth, Dieter; Noël, Jean-Christophe; Jakschitz, Thomas; Rainer, Matthias; Tessadri, Richard; Huck, Christian W; Bonn, Günther K

    2015-07-23

    In this study we report the novel polymeric resin poly(N-vinyl imidazole/ethylene glycol dimethacrylate) for the purification and isolation of phenolic acids. The monomer to crosslinker ratio and the porogen composition were optimized for isolating phenolic acids diluted in acetonitrile at normal phase chromatography conditions, first. Acetonitrile serves as polar, aprotic solvent, dissolving phenolic acids but not interrupting interactions with the stationary phase due to the approved Hansen solubility parameters. The optimized resin demonstrated high loading capacities and adsorption abilities particularly for phenolic acids in both, acetonitrile and aqueous solutions. The adsorption behavior of aqueous standards can be attributed to ion exchange effects due to electrostatic interactions between protonated imidazole residues and deprotonated phenolic acids. Furthermore, adsorption experiments and subsequent curve fittings provide information of maximum loading capacities of single standards according to the Langmuir adsorption model. Recovery studies of the optimized polymer in the normal-phase and ion-exchange mode illustrate the powerful isolation properties for phenolic acids and are comparable or even better than typical, commercially available solid phase extraction materials. In order to prove the applicability, a highly complex extract of rosemary leaves was purified by poly(N-vinyl imidazole/ethylene glycol dimethacrylate) and the isolated compounds were identified using UHPLC-qTOF-MS.

  17. Ethylene-enhanced catabolism of ( sup 14 C)indole-3-acetic acid to indole-3-carboxylic acid in citrus leaf tissues. [Citrus sinensis

    SciTech Connect

    Sagee, O.; Riov, J.; Goren, J. )

    1990-01-01

    Exogenous ({sup 14}C)indole-3-acetic acid (IAA) is conjugated in citrus (Citrus sinensis) leaf tissues to one major substance which has been identified as indole-3-acetylaspartic acid (IAAsp). Ethylene pretreatment enhanced the catabolism of ({sup 14}C)IAA to indole-3-carboxylic acid (ICA), which accumulated as glucose esters (ICGlu). Increased formation of ICGlu by ethylene was accompanied by a concomitant decrease in IAAsp formation. IAAsp and ICGlu were identified by combined gas chromatography-mass spectrometry. Formation of ICGlu was dependent on the concentration of ethylene and the duration of the ethylene pretreatment. It is suggested that the catabolism of IAA to ICA may be one of the mechanisms by which ethylene endogenous IAA levels.

  18. Poly(isophthalic acid)(ethylene oxide) as a Macromolecular Modulator for Metal-Organic Polyhedra.

    PubMed

    Chen, Teng-Hao; Wang, Le; Trueblood, Jonathan V; Grassian, Vicki H; Cohen, Seth M

    2016-08-01

    A new strategy was developed by using a polymer ligand, poly(isophthalic acid)(ethylene oxide), to modulate the growth of metal-organic polyhedra (MOP) crystals. This macromolecular modulator can effectively control the crystal habit of several different Cu24L24 (L = isophthalic acid derivatives) MOPs. The polymer also directed the formation of MOP structures under reaction conditions that only produce metal-organic frameworks in the absence of modulator. Moreover, the polymer also enabled the deposition of MOP crystals on glass surfaces. This macromolecular modulator strategy provides an innovative approach to control the morphology and assembly of MOP particles. PMID:27400759

  19. Interactions between ethylene-bis-nitrourethane and Gibberellic acid during the germination of lettuce seed.

    PubMed

    Morgan, D G

    1968-09-01

    Exposing lettuce seed (variety Grand Rapids) to temperatures from 30°-42° C inhibits subsequent germination at 25° C. This inhibition can be overcome by the addition of gibberellic acid (GA) either during or after the heat treatment. Ethylene-bis-nitrourethane (EBNU) and ethylene dinitramine (EDNA), although without effect when applied alone, have been shown to increase the activity of GA when present in admixture during the heat treatment. The compounds act synergistically only when the seeds are kept at 30° and 35° C for 72 hours or longer.EBNU and EDNA do not increase the effectiveness of GA in breaking natural or heat induced dormancy in lettuce seeds.

  20. Synthesis of elastic biodegradable polyesters of ethylene glycol and butylene glycol from sebacic acid.

    PubMed

    Park, Hyung-seok; Seo, Jung-a; Lee, Hye-Young; Kim, Hae-Won; Wall, Ivan B; Gong, Myoung-Seon; Knowles, Jonathan C

    2012-08-01

    High molecular weight biodegradable polyesters were prepared from sebacic acid, ethylene glycol and butylene glycol through a simple non-solvent polycondensation with a low toxicity catalyst. The successful synthesis of the polyesters was confirmed by gel permeation chromatography, (1)H-nuclear magnetic resonance and Fourier transform-infrared spectroscopies and differential scanning calorimetry. The degradation tests were performed at 37 °C in phosphate buffer solution (pH 7.4) and showed a mass loss of ~5% over 12 weeks compared with only 2% for polycaprolactone (PCL). Reverse transcription polymerase chain reaction results following culture of osteoblasts on the polymer surface showed that poly(ethylene sebacate) and poly(butylene sebacate) films were optimal for osteoblast formation in terms of Runx 2 and osteocalcin gene expression.

  1. Effects of ethylene and gibberellic Acid on cellular growth and development in apical and subapical regions of etiolated pea seedling.

    PubMed

    Stewart, R N; Lieberman, M; Kunishi, A T

    1974-07-01

    Subhook swelling of 4-day-old etiolated pea seedlings (var. Alaska), caused by 0.5 microliter per liter ethylene, was prevented by preincubation and continued growth in 0.1 mm gibberellic acid (GA). The subhook region exhibited normal elongation and cell size and volume. However, inhibition of elongation and cessation of cell division caused by 0.5 microliter per liter ethylene in the apical hook region of the etiolated pea stem were not overcome by GA. Most of the arrested cells were in G(2). These data suggest a possible interaction of GA and ethylene in cell enlargement in the subhook region of the etiolated pea seedlings. They also suggest a different mode of action by ethylene in the apical hook region where the ethylene effect was not counteracted by GA. PMID:16658821

  2. Process dependent thermoelectric properties of EDTA assisted bismuth telluride

    NASA Astrophysics Data System (ADS)

    Kulsi, Chiranjit; Kargupta, Kajari; Banerjee, Dipali

    2016-04-01

    Comparison between the structure and thermoelectric properties of EDTA (Ethylene-diamine-tetra-acetic acid) assisted bismuth telluride prepared by electrochemical deposition and hydrothermal route is reported in the present work. The prepared samples have been structurally characterized by high resolution X-ray diffraction spectra (HRXRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopic images (HRTEM). Crystallite size and strain have been determined from Williamson-Hall plot of XRD which is in conformity with TEM images. Measurement of transport properties show sample in the pellet form (S1) prepared via hydrothermal route has higher value of thermoelectric power (S) than the electrodeposited film (S2). But due to a substantial increase in the electrical conductivity (σ) of the film (S2) over the pellet (S1), the power factor and the figure of merit is higher for sample S2 than the sample S1 at room temperature.

  3. Analysis of metal-EDTA complexes by electrospray mass spectrometry

    SciTech Connect

    Baron, D.; Hering, J.G.

    1998-07-01

    Solutions of the strong complexing agent ethylenediaminetetraacetic acid (EDTA) and Cu, Pb, Cd, Al, and Fe(III) were examined by electrospray mass spectrometry (ES/MS). Uncomplexed EDTA and metal-EDTA complexes survive the electrospray process intact and can be detected simultaneously by mass spectrometry. Best sensitivity was achieved in the positive ion mode in which EDTA and EDTA-metal complexes (present in solution as anions) were detected as protonated species with a single positive charge. Except for the protonation, the aqueous metal-EDTA complexes are preserved and neither fragmentation of complexes nor formation of clusters with more than one metal or ligand were observed in the mass spectra. Detection limits are between approximately 1 to 2 {micro}M for uncomplexed EDTA and for the Cu-EDTA and Pb-EDTA complexes, with a linear range up to 10{sup {minus}4} M. Calibrations based on solutions with equimolar concentrations of EDTA and Cu or Pb can be used to quantify EDTA-metal complexes in solutions with excess EDTA or metal, and in solutions with more than one metal present. Isotopic signatures of metals in the metal-ligand complexes are preserved, allowing the identification of the metal in a metal-ligand complex. Isotopic signatures of metals can therefore aid in the identification of metal-ligand complexes in unknown samples.

  4. Plants having modified response to ethylene by transformation with an ETR nucleic acid

    DOEpatents

    Meyerowitz, Elliott M.; Chang, Caren; Bleecker, Anthony B.

    2001-01-01

    The invention includes transformed plants having at least one cell transformed with a modified ETR nucleic acid. Such plants have a phenotype characterized by a decrease in the response of at least one transformed plant cell to ethylene as compared to a plant not containing the transformed plant cell. Tissue and/or temporal specificity for expression of the modified ETR nucleic acid is controlled by selecting appropriate expression regulation sequences to target the location and/or time of expression of the transformed nucleic acid. The plants are made by transforming at least one plant cell with an appropriate modified ETR nucleic acid, regenerating plants from one or more of the transformed plant cells and selecting at least one plant having the desired phenotype.

  5. An evaluation of EDTA additions for improving the phytoremediation efficiency of different plants under various cultivation systems.

    PubMed

    Luo, Jie; Qi, Shihua; Gu, X W Sophie; Wang, Jinji; Xie, Xianming

    2016-05-01

    Previous studies have shown that phytoremediation usually requires soil amendments, such as chelates, to mobilize low bioavailability heavy metals for better plant absorption and, consequently, for remediation efficiency. A total dry biomass of 3.39 and 0.0138 kg per plant was produced by a phytoremediator, Eucalyptus globulus, and a nitrogen fixing crop, Cicer arietinum (chickpea), respectively. The accumulation of Pb in E. globulus and chickpea reached 1170.61 and 1.33 mg per plant (700 and 324 mg kg(-1)), respectively, under an ethylene diamine tetraacetic acid (EDTA) treatment, which was a five and sixfold increase over the value in untreated experiments, respectively. EDTA enhanced the phytoremediation efficiency and increased the heavy metal concentration in the soil solution. In pot experiments, approximately 27 % of the initial Pb leached from the spiked soil after EDTA and 25 mm artificial precipitation additions into soil without plants, which was considerably larger than the value under the same conditions without EDTA application (7 %). E. globulus planted in a mixed culture had higher water use efficiency than monocultures of either species in field experiments, and E. globulus intercepted almost all of the artificial precipitation in the pot experiments. This study demonstrates that E. globulus can maximize the potential of EDTA for improving the phytoremediation efficiency and minimizing its negative effects to the environment simultaneously by absorbing the metal-rich leachate, especially in a mixed culture of E. globulus and chickpeas. PMID:26846211

  6. Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

    SciTech Connect

    Seol, Yongkoo; Javandel, Iraj

    2008-03-15

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  7. Ethylene Responses in Rice Roots and Coleoptiles Are Differentially Regulated by a Carotenoid Isomerase-Mediated Abscisic Acid Pathway[OPEN

    PubMed Central

    Yin, Cui-Cui; Ma, Biao; Collinge, Derek Phillip; Pogson, Barry James; He, Si-Jie; Xiong, Qing; Duan, Kai-Xuan; Chen, Hui; Yang, Chao; Lu, Xiang; Wang, Yi-Qin; Zhang, Wan-Ke; Chu, Cheng-Cai; Sun, Xiao-Hong; Fang, Shuang; Chu, Jin-Fang; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2015-01-01

    Ethylene and abscisic acid (ABA) act synergistically or antagonistically to regulate plant growth and development. ABA is derived from the carotenoid biosynthesis pathway. Here, we analyzed the interplay among ethylene, carotenoid biogenesis, and ABA in rice (Oryza sativa) using the rice ethylene response mutant mhz5, which displays a reduced ethylene response in roots but an enhanced ethylene response in coleoptiles. We found that MHZ5 encodes a carotenoid isomerase and that the mutation in mhz5 blocks carotenoid biosynthesis, reduces ABA accumulation, and promotes ethylene production in etiolated seedlings. ABA can largely rescue the ethylene response of the mhz5 mutant. Ethylene induces MHZ5 expression, the production of neoxanthin, an ABA biosynthesis precursor, and ABA accumulation in roots. MHZ5 overexpression results in enhanced ethylene sensitivity in roots and reduced ethylene sensitivity in coleoptiles. Mutation or overexpression of MHZ5 also alters the expression of ethylene-responsive genes. Genetic studies revealed that the MHZ5-mediated ABA pathway acts downstream of ethylene signaling to inhibit root growth. The MHZ5-mediated ABA pathway likely acts upstream but negatively regulates ethylene signaling to control coleoptile growth. Our study reveals novel interactions among ethylene, carotenogenesis, and ABA and provides insight into improvements in agronomic traits and adaptive growth through the manipulation of these pathways in rice. PMID:25841037

  8. Abscisic acid, ethylene and gibberellic acid act at different developmental stages to instruct the adaptation of young leaves to stress

    PubMed Central

    Verelst, Wim; Skirycz, Aleksandra

    2010-01-01

    Drought stress represents a particularly great environmental challenge for plants. A decreased water availability can severely limit growth, and this jeopardizes the organism's primary goal—to survive and sustain growth long enough to ensure the plentiful production of viable seeds within the favorable growth season. It is therefore vital for a growing plant to sense oncoming drought as early as possible, and to respond to it rapidly and appropriately in all organs. A typical, fast energy-saving response is the arrest of growth in young organs, which is likely mediated by root-derived signals. A recent publication indicates that three plant hormones (abscisic acid, ethylene and gibberellic acid) mediate the adaptation of leaf growth in response to drought, and that they act at different developmental stages. Abscisic acid mainly acts in mature cells, while ethylene and gibberellic acid function in expanding and dividing leaf cells. This provides the plant with a means to differentially control the developmental zones of a growing leaf, and to integrate environmental signals differently in sink and source tissues. Here we discuss the biological implications of this discovery in the context of long-distance xylem and phloem transport. PMID:20383070

  9. The application of EDTA in drug delivery systems: doxorubicin liposomes loaded via NH4EDTA gradient.

    PubMed

    Song, Yanzhi; Huang, Zhenjun; Song, Yang; Tian, Qingjing; Liu, Xinrong; She, Zhennan; Jiao, Jiao; Lu, Eliza; Deng, Yihui

    2014-01-01

    The applications of ethylenediaminetetraacetic acid (EDTA) have been expanded from the treatment of heavy metal poisoning to chelation therapies for atherosclerosis, heart disease, and cancers, in which EDTA reduces morbidity and mortality by chelating toxic metal ions. In this study, EDTA was used in a drug delivery system by adopting an NH4EDTA gradient method to load doxorubicin into liposomes with the goal of increasing therapeutic effects and decreasing drug-related cytotoxicity. The particle size of the optimum NH4EDTA gradient liposomes was 79.4±1.87 nm, and the entrapment efficiency was 95.54%±0.59%. In vitro studies revealed that liposomes prepared using an NH4EDTA gradient possessed long-term stability and delayed drug release. The in vivo studies also showed the superiority of the new doxorubicin formulation. Compared with an equivalent drug dose (5 mg/kg) prepared by (NH4)2SO4 gradient, NH4EDTA gradient liposomes showed no significant differences in tumor inhibition ratio, but cardiotoxicity and liposome-related immune organ damage were lower, and no drug-related deaths were observed. These results show that use of the NH4EDTA gradient method to load doxorubicin into liposomes could significantly reduce drug toxicity without influencing antitumor activity.

  10. Performance of AA5052 alloy anode in alkaline ethylene glycol electrolyte with dicarboxylic acids additives for aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Wang, DaPeng; Zhang, DaQuan; Lee, KangYong; Gao, LiXin

    2015-11-01

    Dicarboxylic acid compounds, i.e. succinic acid (SUA), adipic acid (ADA) and sebacic acid (SEA), are used as electrolyte additives in the alkaline ethylene glycol solution for AA5052 aluminium-air batteries. It shows that the addition of dicarboxylic acids lowers the hydrogen gas evolution rate of commercial AA5052 aluminium alloy anode. AA5052 aluminium alloy has wide potential window for electrochemical activity and better discharge performance in alkaline ethylene glycol solution containing dicarboxylic acid additives. ADA has the best inhibition effect for the self-corrosion of AA5052 anode among the three dicarboxylic acid additives. Fourier transform infrared spectroscopy (FT-IR) reveals that dicarboxylic acids and aluminium ions can form coordination complexes. Quantum chemical calculations shows that ADA has a smaller energy gap (ΔE, the energy difference between the lowest unoccupied orbital and the highest occupied orbital), indicating that ADA has the strongest interaction with aluminium ions.

  11. Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

    SciTech Connect

    Warangkhana, Phromma; Rathanawan, Magaraphan; Jana Sadhan, C.

    2015-05-22

    The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness.

  12. Foliar Abscisic Acid-To-Ethylene Accumulation and Response Regulate Shoot Growth Sensitivity to Mild Drought in Wheat

    PubMed Central

    Valluru, Ravi; Davies, William J.; Reynolds, Matthew P.; Dodd, Ian C.

    2016-01-01

    Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM) of ABA increased shoot relative growth rate (RGR) in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor) spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early–stage selection tool aiding genotype selection for stress tolerance. PMID:27148292

  13. Effects of Abscisic Acid and Ethylene on the Gibberellic Acid-Induced Synthesis of α-Amylase by Isolated Wheat Aleurone Layers 1

    PubMed Central

    Varty, Keith; Arreguín, Barbarín L.; Gómez, Miguel T.; López, Pablo Jaime T.; Gómez, Miguel Angel L.

    1983-01-01

    Gibberellic acid-induced α-amylase synthesis in wheat aleurone layers (Triticum aestivum L. var Potam S-70) escaped from transcriptional control 30 h after addition of the hormone, as evidenced by the tissue's loss of susceptibility to cordycepin. Abscisic acid inhibited the accumulation of α-amylase activity when added to the tissue during this cordycepin-insensitive phase of enzyme induction. α-Amylase synthesis was not restored by the addition of cordycepin, indicating that the response to abscisic acid was not dependent upon the continuous synthesis of a short lived RNA. When ethylene was added simultaneously or some time after abscisic acid, the accumulation of α-amylase activity was sustained or quickly restored. The loss of susceptibility to cordycepin was completely prevented when aleurone layers were incubated with a combination of gibberellic and abscisic acids from the start of the induction period. This effect of abscisic acid was not reversed by ethylene. On the basis of these observations, it is suggested that abscisic acid inhibits both the transcription and translation of α-amylase mRNA, and that only the latter site of action is susceptible to reversal by ethylene. The rate of incorporation of [methyl-14C]choline into phospholipids was also inhibited by abscisic acid. Ethylene reversed this effect. The effects of abscisic acid and ethylene on phospholipid synthesis were not dependent upon the presence of gibberellic acid. No direct relationship was found between the control of α-amylase synthesis and membrane formation by abscisic acid and ethylene. PMID:16663284

  14. An Ancestral Role for CONSTITUTIVE TRIPLE RESPONSE1 Proteins in Both Ethylene and Abscisic Acid Signaling.

    PubMed

    Yasumura, Yuki; Pierik, Ronald; Kelly, Steven; Sakuta, Masaaki; Voesenek, Laurentius A C J; Harberd, Nicholas P

    2015-09-01

    Land plants have evolved adaptive regulatory mechanisms enabling the survival of environmental stresses associated with terrestrial life. Here, we focus on the evolution of the regulatory CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) component of the ethylene signaling pathway that modulates stress-related changes in plant growth and development. First, we compare CTR1-like proteins from a bryophyte, Physcomitrella patens (representative of early divergent land plants), with those of more recently diverged lycophyte and angiosperm species (including Arabidopsis [Arabidopsis thaliana]) and identify a monophyletic CTR1 family. The fully sequenced P. patens genome encodes only a single member of this family (PpCTR1L). Next, we compare the functions of PpCTR1L with that of related angiosperm proteins. We show that, like angiosperm CTR1 proteins (e.g. AtCTR1 of Arabidopsis), PpCTR1L modulates downstream ethylene signaling via direct interaction with ethylene receptors. These functions, therefore, likely predate the divergence of the bryophytes from the land-plant lineage. However, we also show that PpCTR1L unexpectedly has dual functions and additionally modulates abscisic acid (ABA) signaling. In contrast, while AtCTR1 lacks detectable ABA signaling functions, Arabidopsis has during evolution acquired another homolog that is functionally distinct from AtCTR1. In conclusion, the roles of CTR1-related proteins appear to have functionally diversified during land-plant evolution, and angiosperm CTR1-related proteins appear to have lost an ancestral ABA signaling function. Our study provides new insights into how molecular events such as gene duplication and functional differentiation may have contributed to the adaptive evolution of regulatory mechanisms in plants.

  15. Remediation of metal contaminated soil by EDTA incorporating electrochemical recovery of metal and EDTA

    SciTech Connect

    Allen, H.E.; Chen, P.H. )

    1993-11-01

    Removal of toxic heavy metals from a soil matrix by the addition of ethylenediamine tetraacetic acid (EDTA) is an effective means of remediation. The liquid stream containing the metal and chelating agent is amenable to further treatment by electrolysis in which the metal can be separated from the chelating agent. This provides a separated metal than can be removed for reuse or treated for final disposal by conventional technologies and a reclaimed EDTA stream that can be used again for treatment of contaminated soil. Under the diffusion controlled conditions of polarography or voltammetry, the authors observed reduction of cadmium, copper and lead ions and their protonated EDTA complexes (MHY[sup [minus

  16. Mean platelet volume measurement, EDTA or citrate?

    PubMed

    Dastjerdi, Mansour Siavash; Emami, Tajolmolouk; Najafian, Alireza; Amini, Masoud

    2006-10-01

    Most laboratories use EDTA for anticoagulation of whole blood prior to automated cell counting but due to platelet swelling, mean platelet volume (MPV) values may increase with its use. MPV changes may be less with acid citrate based anticoagulation. As MPV is a marker of platelet function and its precise measurement is important in a number of clinical situations, this study was performed to assess if EDTA and citrate based anticoagulated blood samples can be used interchangeably for MPV measurement. In this cross sectional descriptive study, EDTA and citrate based anticoagulated blood samples of the same patients were assessed by auto-analyzer within 1 h of sampling. In the 61 evaluated patients, there was a close correlation between MPV as measured by EDTA and citrate, but mean MPV measured from EDTA samples was 0.66 fL (9%) more than citrate. There was also a significant negative correlation between platelets count and MPV by both methods. The results of our study reveal that MPV can be measured accurately by both methods of anticoagulation; EDTA and citrate if analysis be performed within 1 h of sampling. PMID:17607580

  17. Alkene to carbyne: tandem Lewis acid activation and dehydrogenation of a molybdenum ethylene complex.

    PubMed

    Stennett, Tom E; Haddow, Mairi F; Wass, Duncan F

    2013-10-18

    Carbyne formation: Treatment of a molybdenum ethylene complex with B(C6 F5 )3 induces ditopic activation of an ethylene ligand and acceptor-assisted ethane elimination to generate a novel type of zwitterionic carbyne complex. PMID:24038792

  18. Acoustic and ultrasonic characterization constraints of self-healing (ethylene-co-methacrylic acid) copolymers

    NASA Astrophysics Data System (ADS)

    Pestka, Kenneth, II; Buckley, Jonathan; Kalista, Stephen; Bowers, Nicholas

    Recent experiments indicate that small sample poly (ethylene-co-methacrylic acid) copolymers (EMAA copolymers) exhibit time dependent variation in their acoustic and ultrasonic resonant spectra after exposure to a damage event. However, due to the relatively soft nature of these thermoplastic materials, several experimental constraints affect efficacy of resonant spectral analysis. In this work we will the address the effect of several characterization constraints on a self-healing EMAA ionomer (commercially known as Dupont Surlyn 8920) including the effects of transducer loading, continuous rapid resonant excitation and temporally separated long-term resonant excitation. In some circumstances, these experimental constraints can influence the time dependence of sample resonant frequency evolution, quality factor, and variation in spectral waveform. By quantifying these effects, robust characterization of post-damage self-healing EMAA samples is possible and will be presented.

  19. Poly(acrylic acid)-poly(ethylene glycol) nanoparticles designed for ophthalmic drug delivery.

    PubMed

    Vasi, Ana-Maria; Popa, Marcel Ionel; Tanase, Edi Constantin; Butnaru, Maria; Verestiuc, Liliana

    2014-02-01

    Poly(acrylic acid) (PAA) and poly(ethylene glycol) (PEG), four-arm, amine-terminated particles with nanometer size and spherical shape were obtained by the polymers cross-linking, via activation with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride, in a w/o emulsion. The morphology and surface charge of the final particles are strongly dependent on the molar ratio of PAA-PEG and the PAA concentration. The physicochemical characteristics correlated with the drug-loading capacity, in vitro and ex vivo release kinetics of pilocarpine hydrochloride and biocompatibility results indicate that these nanoparticles exhibit the prerequisite behavior for use as carriers of ophthalmic drugs. PMID:24357331

  20. Biocompatibility and characterization of polylactic acid/styrene-ethylene-butylene-styrene composites.

    PubMed

    Tsou, Chi-Hui; Kao, Bo-Jyue; Yang, Ming-Chien; Suen, Maw-Cherng; Lee, Yi-Hsuan; Chen, Jui-Chin; Yao, Wei-Hua; Lin, Shang-Ming; Tsou, Chih-Yuan; Huang, Shu-Hsien; De Guzman, Manuel; Hung, Wei-Song

    2015-01-01

    Polylactic acid (PLA)/styrene-ethylene-butylene-styrene (SEBS) composites were prepared by melt blending. Differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WXRD) were used to characterize PLA and PLA/SEBS composites in terms of their melting behavior and crystallization. Curves from thermal gravimetric analysis (TGA) illustrated that thermostability increased with SEBS content. Further morphological analysis of PLA/SEBS composites revealed that SEBS molecules were not miscible with PLA molecules in PLA/SEBS composites. The tensile testing for PLA and PLA/SEBS composites showed that the elongation at the break was enhanced, but tensile strength decreased with increasing SEBS content. L929 fibroblast cells were chosen to assess the cytocompatibility; the cell growth of PLA was found to decrease with increasing SEBS content. This study proposes possible reasons for these properties of PLA/SEBS composites.

  1. Extruded films of blended chitosan, low density polyethylene and ethylene acrylic acid.

    PubMed

    Martínez-Camacho, A P; Cortez-Rocha, M O; Graciano-Verdugo, A Z; Rodríguez-Félix, F; Castillo-Ortega, M M; Burgos-Hernández, A; Ezquerra-Brauer, J M; Plascencia-Jatomea, M

    2013-01-16

    The obtaining of chitosan extruded films was possible by using low density polyethylene (LDPE) as a matrix polymer and ethylene-acrylic acid copolymer as an adhesive, in order to ensure adhesion in the interphase of the immiscible polymers. The obtained blend films were resistant; however, a reduction in the mechanical resistance was observed as chitosan concentration increased. The thermal stability of the films showed a certain grade of interaction between polymers as seen in FTIR spectra. The antifungal activity of the extruded films was assessed against Aspergillus niger and high inhibition percentages were observed, which may be mainly attributed to barrier properties of the extruded films and the limited oxygen availability, resulting in the inability of the fungi to grow. A low adherence of fungal spores to the material surface was observed, mainly in areas with chitosan clumps, which can serve as starting points for material degradation.

  2. Gibbs ensemble Monte Carlo simulation using an optimized potential model: pure acetic acid and a mixture of it with ethylene.

    PubMed

    Zhang, Minhua; Chen, Lihang; Yang, Huaming; Sha, Xijiang; Ma, Jing

    2016-07-01

    Gibbs ensemble Monte Carlo simulation with configurational bias was employed to study the vapor-liquid equilibrium (VLE) for pure acetic acid and for a mixture of acetic acid and ethylene. An improved united-atom force field for acetic acid based on a Lennard-Jones functional form was proposed. The Lennard-Jones well depth and size parameters for the carboxyl oxygen and hydroxyl oxygen were determined by fitting the interaction energies of acetic acid dimers to the Lennard-Jones potential function. Four different acetic acid dimers and the proportions of them were considered when the force field was optimized. It was found that the new optimized force field provides a reasonable description of the vapor-liquid phase equilibrium for pure acetic acid and for the mixture of acetic acid and ethylene. Accurate values were obtained for the saturated liquid density of the pure compound (average deviation: 0.84 %) and for the critical points. The new optimized force field demonstrated greater accuracy and reliability in calculations of the solubility of the mixture of acetic acid and ethylene as compared with the results obtained with the original TraPPE-UA force field.

  3. Impact of extra virgin olive oil and ethylenediaminetetraacetic acid (EDTA) on the oxidative stability of fish oil emulsions and spray-dried microcapsules stabilized by sugar beet pectin.

    PubMed

    Polavarapu, Sudheera; Oliver, Christine M; Ajlouni, Said; Augustin, Mary Ann

    2012-01-11

    The influence of EDTA on lipid oxidation in sugar beet pectin-stabilized oil-in-water emulsions (pH 6, 15% oil, wet basis), prepared from fish oil (FO) and fish oil-extra virgin olive oil (FO-EVOO) (1:1 w/w), as well as the spray-dried microcapsules (50% oil, dry basis) prepared from these emulsions, was investigated. Under accelerated conditions (80 °C, 5 bar oxygen pressure) the oxidative stability was significantly (P < 0.05) higher for FO and FO-EVOO formulated with EDTA, in comparison to corresponding emulsions and spray-dried microcapsules formulated without EDTA. The EDTA effect was greater in emulsions than in spray-dried microcapsules, with the greatest protective effect obtained in FO-EVOO emulsions. EDTA enhanced the oxidative stability of the spray-dried microcapsules during ambient storage (~25 °C, a(w) = 0.5), as demonstrated by their lower concentration of headspace volatile oxidation products, propanal and hexanal. These results show that the addition of EDTA is an effective strategy to maximize the oxidative stability of both FO emulsions and spray-dried microcapsules in which sugar beet pectin is used as the encapsulant material.

  4. Evidence that Bacterial ABC-Type Transporter Imports Free EDTA for Metabolism

    SciTech Connect

    Zhang, Hua; Herman, Jacob P.; Bolton, Harvey; Zhang, Zhicheng; Clark, Sue B.; Xun, Luying

    2007-11-01

    Ethylenediaminetetraacetic acid (EDTA), a common chelating agent, is becoming a major organic pollutant in the form of metal-EDTA complexes in surface waters, partly due to its recalcitrance to biodegradation. Even an EDTA-degrading bacterium BNC1 does not degrade stable metal-EDTA complexes. An ABC-type transporter was identified for possible uptake of EDTA because the transporter genes and EDTA monooxygenase gene were expressed in a single operon in BNC1. The ABC-type transporter had a periplasmic binding protein (EppA) that should confer the substrate specificity for the transporter; therefore, EppA was produced in Escherichia coli,purified, and characterized. EppA was shown to bind free EDTA with a dissociation constant as low as 25 nM by using isothermal titration calorimetry. When unstable metal-EDTA complexes, e.g. MgEDTA2-, were added to the EppA solution, binding was also observed. However, experimental data and theoretical analysis only supported EppA binding of free EDTA. When stable metal-EDTA complexes, e.g. CuEDTA2-, are titrated into the EppA solution, no binding was observed. Since EDTA monooxygenase in the cytoplasm uses some of the stable metal-EDTA complexes as substrates, we suggest that the lack of EppA binding and EDTA uptake are responsible for the failure of BNC1 cells to degrade the stable complexes.

  5. Cyclohexyl EDTA monoanhydride

    DOEpatents

    Mease, R.C.; Srivastava, S.C.

    1991-06-04

    The present invention relates to new rigid chelating structures, to methods for preparing these materials, and to their use in preparing radiometal labeled immunoconjugates. These new chelates include cyclohexyl EDTA monohydride, the transforms of cyclohexyl DTPA and TTHA and derivatives of these cyclohexyl polyaminocarboxylate materials. No Drawings

  6. Cyclohexyl EDTA monoanhydride

    DOEpatents

    Mease, Ronnie C.; Srivastava, Suresh C.

    1991-01-01

    The present invention relates to new rigid chelating structures, to methods for preparing these materials, and to their use in preparing radiometal labeled immunoconjugates. These new chelates include cyclohexyl EDTA monohydride, the transforms of cyclohexyl DTPA and TTHA and derivatives of these cyclohexyl polyaminocarboxylate materials.

  7. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural

    PubMed Central

    Pacheco, Joshua J.; Davis, Mark E.

    2014-01-01

    Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Brønsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Brønsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed. PMID:24912153

  8. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural.

    PubMed

    Pacheco, Joshua J; Davis, Mark E

    2014-06-10

    Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Brønsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Brønsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed. PMID:24912153

  9. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural.

    PubMed

    Pacheco, Joshua J; Davis, Mark E

    2014-06-10

    Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Brønsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Brønsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed.

  10. The influence of different growth stages and dosage of EDTA on Cd uptake and accumulation in Cd-hyperaccumulator (Solanum nigrum L.).

    PubMed

    Sun, Yuebing; Zhou, Qixing; Wang, Lin; Liu, Weitao

    2009-03-01

    Application of synthetic chelates such as ethylene diamine tetraacetic acid (EDTA) has been proposed as an alternative technology for phytoextraction of contaminated soils. In a pot experiment, the effects of EDTA application at three growing stages on growth and Cd uptake and accumulation of Solanum nigrum L. were investigated. The results showed that the 0.1 g/kg EDTA treatment was the most effective treatment, in which the concentrations of Cd in stems and leaves increased significantly compared with the control (Cd only), and the accumulation of Cd in shoots increased by 51.6%, 61.1% and 35.9% at the seedling, flowering and mature stages, respectively. Moreover, at the flowering stage, the height, dry shoot biomass and Cd accumulation in the plants reached the maximum, which were 18.9 cm, 1.8 g/plant and 292.8 microg/pot, respectively. However, higher rate of EDTA (0.5 g/kg) could reduce the plant biomass and the total amount of Cd removed. The results indicated that moderate rate of EDTA applied at the flowering stage would be important to enhance phytoremediation efficiency in practice. PMID:19002363

  11. Comparison of liquid chemical sterilization with peracetic acid and ethylene oxide sterilization for long narrow lumens.

    PubMed

    Alfa, M J; DeGagne, P; Olson, N; Hizon, R

    1998-10-01

    The aim of this study was to determine how well peracetic acid liquid chemical sterilization (LCPAS) killed test organisms in the presence of 10% fetal bovine serum and 0.65% salt challenge (RPMI-S) compared with a 100% ethylene oxide (ETO) sterilizer and an ETO hydrochlorofluorocarbon (ETO-HCFC) sterilization method with long (125 cm), narrow (3-mm internal diameter) flexible lumens as the test carrier. The inoculated lumens were dried overnight before processing. The test organisms included Mycobacterium chelonei, Enterococcus faecalis, and Bacillus subtilis. For all 3 organisms tested, the LCPAS process resulted in a 6 log10 reduction in bacterial load compared with a 2.5 log10 to 6 log10 reduction for the 100% ETO and ETO-HCFC sterilizers. Sterilization was achieved for 100%, 61%, and 67% of the lumen test carriers for the LCPAS, 100% ETO, and ETO-HCFC sterilizers, respectively. The data indicate that of the sterilization methods evaluated, LCPAS was the most effective for sterilizing narrow flexible lumens in the presence of residual inorganic and organic soil. This effectiveness was achieved through a combination of organism wash-off and peracetic acid sterilant killing of organisms. Salt was the major compounding factor for effective ETO gas sterilization, because carriers inoculated with organisms in 10% fetal bovine serum alone all were sterilized by both 100% ETO and ETO-HCFC sterilization methods. Our data support the critical need to ensure adequate precleaning of narrow flexible lumen endoscopes before any sterilization method. PMID:9795674

  12. Comparison of liquid chemical sterilization with peracetic acid and ethylene oxide sterilization for long narrow lumens.

    PubMed

    Alfa, M J; DeGagne, P; Olson, N; Hizon, R

    1998-10-01

    The aim of this study was to determine how well peracetic acid liquid chemical sterilization (LCPAS) killed test organisms in the presence of 10% fetal bovine serum and 0.65% salt challenge (RPMI-S) compared with a 100% ethylene oxide (ETO) sterilizer and an ETO hydrochlorofluorocarbon (ETO-HCFC) sterilization method with long (125 cm), narrow (3-mm internal diameter) flexible lumens as the test carrier. The inoculated lumens were dried overnight before processing. The test organisms included Mycobacterium chelonei, Enterococcus faecalis, and Bacillus subtilis. For all 3 organisms tested, the LCPAS process resulted in a 6 log10 reduction in bacterial load compared with a 2.5 log10 to 6 log10 reduction for the 100% ETO and ETO-HCFC sterilizers. Sterilization was achieved for 100%, 61%, and 67% of the lumen test carriers for the LCPAS, 100% ETO, and ETO-HCFC sterilizers, respectively. The data indicate that of the sterilization methods evaluated, LCPAS was the most effective for sterilizing narrow flexible lumens in the presence of residual inorganic and organic soil. This effectiveness was achieved through a combination of organism wash-off and peracetic acid sterilant killing of organisms. Salt was the major compounding factor for effective ETO gas sterilization, because carriers inoculated with organisms in 10% fetal bovine serum alone all were sterilized by both 100% ETO and ETO-HCFC sterilization methods. Our data support the critical need to ensure adequate precleaning of narrow flexible lumen endoscopes before any sterilization method.

  13. Novel microbial screen for detection of 1,4-butanediol, ethylene glycol, and adipic acid.

    PubMed

    Stieglitz, B; Weimer, P J

    1985-03-01

    A novel microbial-screening procedure was developed for separate detection of 1,4-butanediol, ethylene glycol, and adipic acid, three commercially important oxychemicals potentially derivable from bacterial omega-oxidation of n-butanol, ethanol, and hexanoic acid, respectively. The screening method involved postproduction addition of one of several specific Pseudomonas strains which produce a soluble fluorescent pigment during growth on the product of interest. A mutation and selection procedure was developed for isolation of specific strains with phenotypes for growth and pigment production on the desired product (e.g., 1,4-butanediol), but not on its bioconversion substrate (e.g., n-butanol), common by-products (e.g., n-butyrate), or product isomers. Pigment production was growth associated and required cultivation of the screening strains under limiting Fe3+ concentrations. The pigments resembled well-characterized, iron-chelating siderophores produced by other fluorescent pseudomonads. The sensitivity of the assay for product accumulation was enhanced by (i) conducting the screening in microtiter dishes to permit examination of individual isolates of putative producers and to control product diffusion, (ii) using a wavelength cutoff filter to reduce background source light, and (iii) using adapted screening strains which grew at lower (0.3 mM) concentrations of test compounds. The potential utility of the method for detecting a variety of oxidative catabolic products is discussed.

  14. Salicylic acid differently impacts ethylene and polyamine synthesis in the glycophyte Solanum lycopersicum and the wild-related halophyte Solanum chilense exposed to mild salt stress.

    PubMed

    Gharbi, Emna; Martínez, Juan-Pablo; Benahmed, Hela; Fauconnier, Marie-Laure; Lutts, Stanley; Quinet, Muriel

    2016-10-01

    This study aimed to determine the effects of exogenous application of salicylic acid (SA) on the toxic effects of salt in relation to ethylene and polyamine synthesis, and to correlate these traits with the expression of genes involved in ethylene and polyamine metabolism in two tomato species differing in their sensitivity to salt stress, Solanum lycopersicum cv Ailsa Craig and its wild salt-resistant relative Solanum chilense. In S. chilense, treatment with 125 mM NaCl improved plant growth, increased production of ethylene, endogenous salicylic acid and spermine. The production was related to a modification of expression of genes involved in ethylene and polyamine metabolism. In contrast, salinity decreased plant growth in S. lycopersicum without affecting endogenous ethylene, salicylic or polyamine concentrations. Exogenous application of salicylic acid at 0.01 mM enhanced shoot growth in both species and affected ethylene and polyamine production in S. chilense. Concomitant application of NaCl and salicylic acid improved osmotic adjustment, thus suggesting that salt and SA may act in synergy on osmolyte synthesis. However, the beneficial impact of exogenous application of salicylic acid was mitigated by salt stress since NaCl impaired endogenous SA accumulation in the shoot and salicylic acid did not improve plant growth in salt-treated plants. Our results thus revealed that both species respond differently to salinity and that salicylic acid, ethylene and polyamine metabolisms are involved in salt resistance in S. chilense. PMID:27105808

  15. Salicylic acid differently impacts ethylene and polyamine synthesis in the glycophyte Solanum lycopersicum and the wild-related halophyte Solanum chilense exposed to mild salt stress.

    PubMed

    Gharbi, Emna; Martínez, Juan-Pablo; Benahmed, Hela; Fauconnier, Marie-Laure; Lutts, Stanley; Quinet, Muriel

    2016-10-01

    This study aimed to determine the effects of exogenous application of salicylic acid (SA) on the toxic effects of salt in relation to ethylene and polyamine synthesis, and to correlate these traits with the expression of genes involved in ethylene and polyamine metabolism in two tomato species differing in their sensitivity to salt stress, Solanum lycopersicum cv Ailsa Craig and its wild salt-resistant relative Solanum chilense. In S. chilense, treatment with 125 mM NaCl improved plant growth, increased production of ethylene, endogenous salicylic acid and spermine. The production was related to a modification of expression of genes involved in ethylene and polyamine metabolism. In contrast, salinity decreased plant growth in S. lycopersicum without affecting endogenous ethylene, salicylic or polyamine concentrations. Exogenous application of salicylic acid at 0.01 mM enhanced shoot growth in both species and affected ethylene and polyamine production in S. chilense. Concomitant application of NaCl and salicylic acid improved osmotic adjustment, thus suggesting that salt and SA may act in synergy on osmolyte synthesis. However, the beneficial impact of exogenous application of salicylic acid was mitigated by salt stress since NaCl impaired endogenous SA accumulation in the shoot and salicylic acid did not improve plant growth in salt-treated plants. Our results thus revealed that both species respond differently to salinity and that salicylic acid, ethylene and polyamine metabolisms are involved in salt resistance in S. chilense.

  16. Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

    PubMed

    Arslan, Hakan; Yeter, Kübra Y; Karatas, Ertugrul; Yilmaz, Cenk B; Ayranci, Leyla B; Ozsu, Damla

    2015-02-01

    The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA.

  17. Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

    PubMed

    Arslan, Hakan; Yeter, Kübra Y; Karatas, Ertugrul; Yilmaz, Cenk B; Ayranci, Leyla B; Ozsu, Damla

    2015-02-01

    The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA. PMID:23793370

  18. 4,4,4-trifluoro-3-(indole-3-)butyric acid promotes root elongation in Lactuca sativa independent of ethylene synthesis and pH

    NASA Technical Reports Server (NTRS)

    Zhang, Nenggang; Hasenstein, Karl H.

    2002-01-01

    We studied the mode of action of 4,4,4-trifluoro-3- (indole-3-) butyric acid (TFIBA), a recently described root growth stimulator, on primary root growth of Lactuca sativa L. seedlings. TFIBA (100 micromoles) promoted elongation of primary roots by 40% in 72 h but inhibited hypocotyl growth by 35%. TFIBA induced root growth was independent of pH. TFIBA did not affect ethylene production, but reduced the inhibitory effect of ethylene on root elongation. TFIBA promoted root growth even in the presence of the ethylene biosynthesis inhibitor L-alpha-(2-aminoethoxyvinyl)glycine. TFIBA and the ethylene-binding inhibitor silver thiosulphate (STS) had a similar effect on root elongation. The results indicate that TFIBA-stimulated root elongation was neither pH-dependent nor related to inhibition of ethylene synthesis, but was possibly related to ethylene action.

  19. The immobilization of enzymes onto poly(ethylene)—g.co—methacrylic acid, [poly(ethylene)—g.co—hydroxyethyl methacrylate]—g.co—methacrylic acid and [poly(ethylene)—g.co—methacrylic acid]—g.co—hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Da Silva, M. Alves; Gil, M. H.; Guiomar, J.; Lapa, E.; Machado, E.; Moreira, M.; Guthrie, J. T.; Kotov, S.

    A series of graft copolymers has been prepared based on the poly(ethylene) backbone. These carry functional groups which are effective in coupling and provide a level of hydrophilicity which is thought to be consistent with generating a suitable micro-environment for enzyme immobilization and subsequent enhanced biocatalyst stability. Four enzymes have been immobilized. These are papain, trypsin, glucose oxidase and α-chymotrypsin. The parent copolymers were assembled via radiation-induced grafting. Secondary grafting was achieved in two ways. The first involved grafting methacrylic acid onto poly(ethylene)—g.co—hydroxyethyl methacrylate, while the second involved grafting hydroxyethyl methacrylate onto poly(ethylene)—g.co—methacrylic acid. The results suggest that a high degree of specificity arises in the systems examined with regard to the enzymes, the type of copolymers and the coupling procedures. Generally, relatively large amounts of enzyme become covalently attached to the copolymers, though the overall level of activity is low. In this work it has been observed that the most satisfactory results were obtained when the partly hydrolyzed poly(ethylene)—g.co—hydroxyethyl methacrylate was used in the immobilization of the biocatalysts.

  20. Ethylene, seed germination, and epinasty.

    PubMed

    Stewart, E R; Freebairn, H T

    1969-07-01

    Ethylene activity in lettuce seed (Lactuca satina) germination and tomato (Lycopersicon esculentum) petiole epinasty has been characterized by using heat to inhibit ethylene synthesis. This procedure enabled a separation of the production of ethylene from the effect of ethylene. Ethylene was required in tomato petioles to produce the epinastic response and auxin was found to be active in producing epinasty through a stimulation of ethylene synthesis with the resulting ethylene being responsible for the epinasty. In the same manner, it was shown that gibberellic acid stimulated ethylene synthesis in lettuce seeds. The ethylene produced then in turn stimulated the seeds to germinate. It was hypothesized that ethylene was the intermediate which caused epinasty or seed germination. Auxin and gibberellin primarily induced their response by stimulating ethylene production.

  1. Arabidopsis MAP kinase 4 regulates salicylic acid- and jasmonic acid/ethylene-dependent responses via EDS1 and PAD4.

    PubMed

    Brodersen, Peter; Petersen, Morten; Bjørn Nielsen, Henrik; Zhu, Shijiang; Newman, Mari-Anne; Shokat, Kevan M; Rietz, Steffen; Parker, Jane; Mundy, John

    2006-08-01

    Arabidopsis MPK4 has been implicated in plant defense regulation because mpk4 knockout plants exhibit constitutive activation of salicylic acid (SA)-dependent defenses, but fail to induce jasmonic acid (JA) defense marker genes in response to JA. We show here that mpk4 mutants are also defective in defense gene induction in response to ethylene (ET), and that they are more susceptible than wild-type (WT) to Alternaria brassicicola that induces the ET/JA defense pathway(s). Both SA-repressing and ET/JA-(co)activating functions depend on MPK4 kinase activity and involve the defense regulators EDS1 and PAD4, as mutations in these genes suppress de-repression of the SA pathway and suppress the block of the ET/JA pathway in mpk4. EDS1/PAD4 thus affect SA-ET/JA signal antagonism as activators of SA but as repressors of ET/JA defenses, and MPK4 negatively regulates both of these functions. We also show that the MPK4-EDS1/PAD4 branch of ET defense signaling is independent of the ERF1 transcription factor, and use comparative microarray analysis of ctr1, ctr1/mpk4, mpk4 and WT to show that MPK4 is required for induction of a small subset of ET-regulated genes. The regulation of some, but not all, of these genes involves EDS1 and PAD4.

  2. Morphological Origin of Thermomechanical Behavior in Semicrystalline Ethylene/Methacrylic Acid Ionomers

    NASA Astrophysics Data System (ADS)

    Wakabayashi, Katsuyuki; Register, Richard A.

    2006-03-01

    Two peculiar and intriguing phenomena in ethylene/methacrylic acid (E/MAA) ionomers are an initial sharp increase in stiffness with neutralization and an inverse dependence of Young’s modulus on crystallinity. We have identified how the polyethylene crystallites, amorphous polymer segments, and ionic aggregates combine to produce these unusual effects. At temperatures just below the melting point of the primary crystallites, the ionomers can be satisfactorily described as two-phase composites of crystallites and ionically-crosslinked rubber, but at room temperature, the modulus is much greater. We trace this effect to a synergy between the ionic aggregates and secondary crystallites, which together form percolated rigid pathways through the amorphous phase at room temperature, generating a far higher modulus than one would anticipate from the modest crystallinity and ion content. When the secondary crystallites melt and/or the segments in the regions of restricted mobility surrounding the aggregates devitrify, these paths break down and the simple two-phase composite description is recovered.

  3. Effects of organic acids on the photosynthetic and antioxidant properties and accumulations of heavy metals of Melilotus officinalis grown in Cu tailing.

    PubMed

    Han, Yulin; Wu, Xue; Gu, Jiguang; Zhao, Jiuzhou; Huang, Suzhen; Yuan, Haiyan; Fu, Jiajia

    2016-09-01

    The effect of citric acid (CA), acetic acid (Ac), and ethylene diamine tetraacetic acid (EDTA) on the photosynthetic and antioxidant properties and the accumulation of some heavy metals (HMs) of Melilotus officinalis seedling growing in Cu mine tailings for 25 days were studied. Results showed that the formation of photosynthesizing cells of M. officinalis was inhibited by EDTA at 2 mmol/kg. Photosynthetic pigment contents under EDTA of 2 mmol/kg were reduced by 26, 40, and 19 %, respectively, compared to the control. The proline contents in aboveground and underground parts increased as the level of EDTA was enhanced. CA and Ac enhanced the activities of superoxide dismutase (SOD) and peroxidase (POD) in the aboveground parts and EDTA inhibited the activity of POD in the underground parts. The addition of CA promoted significantly the growth of M. officinalis, while the biomass decreased significantly under 2 mmol/kg EDTA. Cu contents in the aboveground parts treated with 0.5 and 2.0 mmol/kg EDTA reached 175.50 and 265.17 μg/g dry weight, respectively. Ac and EDTA treatments promoted Cd to translocate from root to aboveground parts. The result indicated that M. officinalis was a tolerant species of Cu tailing and can be used to remediate Cu contaminated environment, and rationally utilization of organic acids, especially EDTA, in the phytoremediation can improve the growth and metals accumulation of M. officinalis. PMID:27255310

  4. Effects of organic acids on the photosynthetic and antioxidant properties and accumulations of heavy metals of Melilotus officinalis grown in Cu tailing.

    PubMed

    Han, Yulin; Wu, Xue; Gu, Jiguang; Zhao, Jiuzhou; Huang, Suzhen; Yuan, Haiyan; Fu, Jiajia

    2016-09-01

    The effect of citric acid (CA), acetic acid (Ac), and ethylene diamine tetraacetic acid (EDTA) on the photosynthetic and antioxidant properties and the accumulation of some heavy metals (HMs) of Melilotus officinalis seedling growing in Cu mine tailings for 25 days were studied. Results showed that the formation of photosynthesizing cells of M. officinalis was inhibited by EDTA at 2 mmol/kg. Photosynthetic pigment contents under EDTA of 2 mmol/kg were reduced by 26, 40, and 19 %, respectively, compared to the control. The proline contents in aboveground and underground parts increased as the level of EDTA was enhanced. CA and Ac enhanced the activities of superoxide dismutase (SOD) and peroxidase (POD) in the aboveground parts and EDTA inhibited the activity of POD in the underground parts. The addition of CA promoted significantly the growth of M. officinalis, while the biomass decreased significantly under 2 mmol/kg EDTA. Cu contents in the aboveground parts treated with 0.5 and 2.0 mmol/kg EDTA reached 175.50 and 265.17 μg/g dry weight, respectively. Ac and EDTA treatments promoted Cd to translocate from root to aboveground parts. The result indicated that M. officinalis was a tolerant species of Cu tailing and can be used to remediate Cu contaminated environment, and rationally utilization of organic acids, especially EDTA, in the phytoremediation can improve the growth and metals accumulation of M. officinalis.

  5. Ethylene Biosynthesis Is Promoted by Very-Long-Chain Fatty Acids during Lysigenous Aerenchyma Formation in Rice Roots.

    PubMed

    Yamauchi, Takaki; Shiono, Katsuhiro; Nagano, Minoru; Fukazawa, Aya; Ando, Miho; Takamure, Itsuro; Mori, Hitoshi; Nishizawa, Naoko K; Kawai-Yamada, Maki; Tsutsumi, Nobuhiro; Kato, Kiyoaki; Nakazono, Mikio

    2015-09-01

    In rice (Oryza sativa) roots, lysigenous aerenchyma, which is created by programmed cell death and lysis of cortical cells, is constitutively formed under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. Ethylene is involved in the induction of aerenchyma formation. reduced culm number1 (rcn1) is a rice mutant in which the gene encoding the ATP-binding cassette transporter RCN1/OsABCG5 is defective. Here, we report that the induction of aerenchyma formation was reduced in roots of rcn1 grown in stagnant deoxygenated nutrient solution (i.e. under stagnant conditions, which mimic oxygen-deficient conditions in waterlogged soils). 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is a key enzyme in ethylene biosynthesis. Stagnant conditions hardly induced the expression of ACS1 in rcn1 roots, resulting in low ethylene production in the roots. Accumulation of saturated very-long-chain fatty acids (VLCFAs) of 24, 26, and 28 carbons was reduced in rcn1 roots. Exogenously supplied VLCFA (26 carbons) increased the expression level of ACS1 and induced aerenchyma formation in rcn1 roots. Moreover, in rice lines in which the gene encoding a fatty acid elongase, CUT1-LIKE (CUT1L; a homolog of the gene encoding Arabidopsis CUT1, which is required for cuticular wax production), was silenced, both ACS1 expression and aerenchyma formation were reduced. Interestingly, the expression of ACS1, CUT1L, and RCN1/OsABCG5 was induced predominantly in the outer part of roots under stagnant conditions. These results suggest that, in rice under oxygen-deficient conditions, VLCFAs increase ethylene production by promoting 1-aminocyclopropane-1-carboxylic acid biosynthesis in the outer part of roots, which, in turn, induces aerenchyma formation in the root cortex.

  6. Ethylene Biosynthesis Is Promoted by Very-Long-Chain Fatty Acids during Lysigenous Aerenchyma Formation in Rice Roots1

    PubMed Central

    Yamauchi, Takaki; Shiono, Katsuhiro; Nagano, Minoru; Fukazawa, Aya; Ando, Miho; Takamure, Itsuro; Mori, Hitoshi; Nishizawa, Naoko K.; Kawai-Yamada, Maki; Tsutsumi, Nobuhiro; Kato, Kiyoaki; Nakazono, Mikio

    2015-01-01

    In rice (Oryza sativa) roots, lysigenous aerenchyma, which is created by programmed cell death and lysis of cortical cells, is constitutively formed under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. Ethylene is involved in the induction of aerenchyma formation. reduced culm number1 (rcn1) is a rice mutant in which the gene encoding the ATP-binding cassette transporter RCN1/OsABCG5 is defective. Here, we report that the induction of aerenchyma formation was reduced in roots of rcn1 grown in stagnant deoxygenated nutrient solution (i.e. under stagnant conditions, which mimic oxygen-deficient conditions in waterlogged soils). 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is a key enzyme in ethylene biosynthesis. Stagnant conditions hardly induced the expression of ACS1 in rcn1 roots, resulting in low ethylene production in the roots. Accumulation of saturated very-long-chain fatty acids (VLCFAs) of 24, 26, and 28 carbons was reduced in rcn1 roots. Exogenously supplied VLCFA (26 carbons) increased the expression level of ACS1 and induced aerenchyma formation in rcn1 roots. Moreover, in rice lines in which the gene encoding a fatty acid elongase, CUT1-LIKE (CUT1L; a homolog of the gene encoding Arabidopsis CUT1, which is required for cuticular wax production), was silenced, both ACS1 expression and aerenchyma formation were reduced. Interestingly, the expression of ACS1, CUT1L, and RCN1/OsABCG5 was induced predominantly in the outer part of roots under stagnant conditions. These results suggest that, in rice under oxygen-deficient conditions, VLCFAs increase ethylene production by promoting 1-aminocyclopropane-1-carboxylic acid biosynthesis in the outer part of roots, which, in turn, induces aerenchyma formation in the root cortex. PMID:26036614

  7. Requirement for Ethylene Synthesis and Action during Relief of Thermoinhibition of Lettuce Seed Germination by Combinations of Gibberellic Acid, Kinetin, and Carbon Dioxide.

    PubMed

    Saini, H S; Consolacion, E D; Bassi, P K; Spencer, M S

    1986-08-01

    Application of exogenous ethylene in combination with gibberellic acid (GA(3)), kinetin (KIN), and/or CO(2) has been reported to induce germination of lettuce seeds at supraoptimal temperatures. However, it is not clear whether endogenous ethylene also plays a mediatory role when germination under these conditions is induced by treatment regimes that do not include ethylene. Therefore, possible involvement of endogenous ethylene during the relief of thermoinhibition of lettuce (Lactuca sativa L. cv Grand Rapids) seed germination at 32 degrees C was investigated. Combinations of GA(3) (0.5 millimolar), KIN (0.05 millimolar), and CO(2) (10%) were used to induce germination. Little germination occurred in controls or upon treatment with ethylene, KIN, or CO(2). Neither KIN nor CO(2) affected the rate of ethylene production by seeds. Both germination and ethylene production were slightly promoted by GA(3). Treatments with GA(3)+CO(2), GA(3)+KIN, or GA(3)+CO(2)+KIN resulted in approximately 10-to 40-fold increases in ethylene production and 50 to 100% promotion of germination as compared to controls. Initial ethylene evolution from the treated seeds was greater than from the controls and a major surge in ethylene evolution occurred at the time of visible germination. Application of 1 millimolar 2-aminoethoxyvinyl glycine (AVG), an inhibitor of ethylene synthesis, in combination with any of above three treatments inhibited the ethylene production to below control levels. This was accompanied by a marked decline in germination percentage. Germination was also inhibited by 2,5-norbornadiene (0.25-2 milliliters per liter), a competitive inhibitor of ethylene action. Application of exogenous ethylene (1-100 microliters per liter) overcame the inhibitory effects of AVG and 2,5-norbornadiene on germination. The results demonstrate that endogenous ethylene synthesis and action are essential for the alleviation of thermoinhibition of lettuce seeds by combinations of GA(3), KIN

  8. Dexamethasone-loaded poly(D, L-lactic acid) microspheres/poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) micelles composite for skin augmentation.

    PubMed

    Fan, Min; Liao, Jinfeng; Guo, Gang; Ding, Qiuxia; Yang, Yi; Luo, Feng; Qian, Zhiyong

    2014-04-01

    Soft tissue augmentation using various injectable fillers has gained popularity as more patients seek esthetic improvement through minimally invasive procedures requiring little or no recovery time. The currently available injectable skin fillers can be divided into three categories. With careful assessment, stimulatory fillers are the most ideal fillers. In this study, dexamethasone-loaded poly(D, L-lactic acid) (PLA) microspheres of approximately 90 micro m suspended in poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) micelles were prepared as stimulatory filler for skin augmentation. The biodegradable PECE copolymer can form nano-sized micelles in water, which instantly turns into a non-flowing gel at body temperature due to micellar aggregation. The PECE micelles (making up 90% of composite) served as vehicle for subcutaneous injection were metabolized within 44 days. At the same time, the dexamethasone-loaded PLA microspheres (10% of composite) merely served as stimulus for connective tissue formation. Dexamethasone-loaded PLA microspheres/PECE micelles composite presented great hemocompatibility in vitro. It was demonstrated in the in vive study that the composite was biodegradable, biocompatible, nontoxic and nonmigratory. Histopathological studies indicated that the composite could stimulate collagen regeneration. Furthermore, granuloma, the main complication of the stimulatory fillers, did not appear when the composite was injected into the back of SD rats, because of the dexamethasone controlled release from the composite. All results suggested that dexamethasone-loaded PLA microspheres/PECE micelles composite may be an efficient and promising biomaterial for skin augmentation. PMID:24734511

  9. Dexamethasone-loaded poly(D, L-lactic acid) microspheres/poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) micelles composite for skin augmentation.

    PubMed

    Fan, Min; Liao, Jinfeng; Guo, Gang; Ding, Qiuxia; Yang, Yi; Luo, Feng; Qian, Zhiyong

    2014-04-01

    Soft tissue augmentation using various injectable fillers has gained popularity as more patients seek esthetic improvement through minimally invasive procedures requiring little or no recovery time. The currently available injectable skin fillers can be divided into three categories. With careful assessment, stimulatory fillers are the most ideal fillers. In this study, dexamethasone-loaded poly(D, L-lactic acid) (PLA) microspheres of approximately 90 micro m suspended in poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) micelles were prepared as stimulatory filler for skin augmentation. The biodegradable PECE copolymer can form nano-sized micelles in water, which instantly turns into a non-flowing gel at body temperature due to micellar aggregation. The PECE micelles (making up 90% of composite) served as vehicle for subcutaneous injection were metabolized within 44 days. At the same time, the dexamethasone-loaded PLA microspheres (10% of composite) merely served as stimulus for connective tissue formation. Dexamethasone-loaded PLA microspheres/PECE micelles composite presented great hemocompatibility in vitro. It was demonstrated in the in vive study that the composite was biodegradable, biocompatible, nontoxic and nonmigratory. Histopathological studies indicated that the composite could stimulate collagen regeneration. Furthermore, granuloma, the main complication of the stimulatory fillers, did not appear when the composite was injected into the back of SD rats, because of the dexamethasone controlled release from the composite. All results suggested that dexamethasone-loaded PLA microspheres/PECE micelles composite may be an efficient and promising biomaterial for skin augmentation.

  10. Health Hazard Evaluation Report HETA 83-166-1594, Witco Chemical Corporation, Perth Amboy, New Jersey. [Ethylene oxide, glycols, and adipic acid

    SciTech Connect

    Cummings, C.E.; Roseman, J.

    1985-05-01

    Area and personel air samples were analyzed for ethylene oxide, glycols, and adipic-acid at the Witco Chemical Corporation, Perth Amboy, New Jersey from November to December, 1983 and May, 1984. The evaluation was requested by the union to investigate possible health effects due to polychlorinated biphenyls (PCBs), glycols, and ethylene oxide. The evaluation was assigned to the New Jersey State Department of Health. The authors conclude that health hazards due to ethylene oxide and airborne fatty acid exposures exist. Recommendations include improving ventilation and work practices and implementing an OSHA approved respirator program.

  11. [Effect of salicylic acid on water potential, ethylene secretion and activity of antioxidative processes in the winter wheat leaves under drought conditions].

    PubMed

    Mamenko, T P; Iaroshenko, O A

    2009-01-01

    Effect of plants treatment by salicylic acid on the water potential, ethylene emission, intensity of lipid peroxidation oxidation and enzymatic antioxidative activity in the leaves with contrasting drought-resistance of winter wheat cultivars was investigated. It is ascertain, that the treatment of plants by salicylic acid contributes to a decrease of water loss and intensity of lipid peroxidation, to an increase of ethylene synthesis and peroxidase, catalase, superoxide dismutase activity in the winter wheat leaves under drought conditions.

  12. Ethylene Interacts with Abscisic Acid to Regulate Endosperm Rupture during Germination: A Comparative Approach Using Lepidium sativum and Arabidopsis thaliana[W][OA

    PubMed Central

    Linkies, Ada; Müller, Kerstin; Morris, Karl; Turečková, Veronika; Wenk, Meike; Cadman, Cassandra S.C.; Corbineau, Françoise; Strnad, Miroslav; Lynn, James R.; Finch-Savage, William E.; Leubner-Metzger, Gerhard

    2009-01-01

    The micropylar endosperm cap covering the radicle in the mature seeds of most angiosperms acts as a constraint that regulates seed germination. Here, we report on a comparative seed biology study with the close Brassicaceae relatives Lepidium sativum and Arabidopsis thaliana showing that ethylene biosynthesis and signaling regulate seed germination by a mechanism that requires the coordinated action of the radicle and the endosperm cap. The larger seed size of Lepidium allows direct tissue-specific biomechanical, biochemical, and transcriptome analyses. We show that ethylene promotes endosperm cap weakening of Lepidium and endosperm rupture of both species and that it counteracts the inhibitory action of abscisic acid (ABA) on these two processes. Cross-species microarrays of the Lepidium micropylar endosperm cap and the radicle show that the ethylene-ABA antagonism involves both tissues and has the micropylar endosperm cap as a major target. Ethylene counteracts the ABA-induced inhibition without affecting seed ABA levels. The Arabidopsis loss-of-function mutants ACC oxidase2 (aco2; ethylene biosynthesis) and constitutive triple response1 (ethylene signaling) are impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germination. Ethylene production by the ACC oxidase orthologs Lepidium ACO2 and Arabidopsis ACO2 appears to be a key regulatory step. Endosperm cap weakening and rupture are promoted by ethylene and inhibited by ABA to regulate germination in a process conserved across the Brassicaceae. PMID:20023197

  13. EDTA enhances high-throughput two-dimensional bioprinting by inhibiting salt scaling and cell aggregation at the nozzle surface.

    PubMed

    Parzel, Cheryl A; Pepper, Matthew E; Burg, Timothy; Groff, Richard E; Burg, Karen J L

    2009-06-01

    Tissue-engineering strategies may be employed in the development of in vitro breast tissue models for use in testing regimens of drug therapies and vaccines. The physical and chemical interactions that occur among cells and extracellular matrix components can also be elucidated with these models to gain an understanding of the progression of transformed epithelial cells into tumours and the ultimate metastases of tumour cells. The modified inkjet printer may be a useful tool for creating three-dimensional (3D) in vitro models, because it offers an inexpensive and high-throughput solution to microfabrication, and because the printer can be easily manipulated to produce varying tissue attributes. We hypothesized, however, that when ink is replaced with a biologically based fluid (i.e. a 'bio-ink'), specifically a serum-free cell culture medium, printer nozzle failure can result from salt scale build-up as fluid evaporates on the printhead surface. In this study, ethylene diamine tetra-acetic acid (EDTA) was used as a culture medium additive to prevent salt scaling and cell aggregation during the bioprinting process. The results showed that EDTA, at a concentration typically found in commercially available trypsin solutions (0.53 mM), prevented nozzle failure when a serum-free culture medium was printed from a nozzle at 1000 drops/s. Furthermore, increasing concentrations of EDTA appeared to mildly decrease aggregation of 4T07 cells. Cell viability studies were performed to demonstrate that addition of EDTA did not result in significant cell death. In conclusion, it is recommended that EDTA be incorporated into bio-ink solutions containing salts that could lead to nozzle failure.

  14. Gibberellic Acid, Synthetic Auxins, and Ethylene Differentially Modulate α-l-Arabinofuranosidase Activities in Antisense 1-Aminocyclopropane-1-Carboxylic Acid Synthase Tomato Pericarp Discs1

    PubMed Central

    Sozzi, Gabriel O.; Greve, L. Carl; Prody, Gerry A.; Labavitch, John M.

    2002-01-01

    α-l-Arabinofuranosidases (α-Afs) are plant enzymes capable of releasing terminal arabinofuranosyl residues from cell wall matrix polymers, as well as from different glycoconjugates. Three different α-Af isoforms were distinguished by size exclusion chromatography of protein extracts from control tomatoes (Lycopersicon esculentum) and an ethylene synthesis-suppressed (ESS) line expressing an antisense 1-aminocyclopropane-1-carboxylic synthase transgene. α-Af I and II are active throughout fruit ontogeny. α-Af I is the first Zn-dependent cell wall enzyme isolated from tomato pericarp tissues, thus suggesting the involvement of zinc in fruit cell wall metabolism. This isoform is inhibited by 1,10-phenanthroline, but remains stable in the presence of NaCl and sucrose. α-Af II activity accounts for over 80% of the total α-Af activity in 10-d-old fruit, but activity drops during ripening. In contrast, α-Af III is ethylene dependent and specifically active during ripening. α-Af I released monosaccharide arabinose from KOH-soluble polysaccharides from tomato cell walls, whereas α-Af II and III acted on Na2CO3-soluble pectins. Different α-Af isoform responses to gibberellic acid, synthetic auxins, and ethylene were followed by using a novel ESS mature-green tomato pericarp disc system. α-Af I and II activity increased when gibberellic acid or 2,4-dichlorophenoxyacetic acid was applied, whereas ethylene treatment enhanced only α-Af III activity. Results suggest that tomato α-Afs are encoded by a gene family under differential hormonal controls, and probably have different in vivo functions. The ESS pericarp explant system allows comprehensive studies involving effects of physiological levels of different growth regulators on gene expression and enzyme activity with negligible wound-induced ethylene production. PMID:12114586

  15. Gibberellic acid, synthetic auxins, and ethylene differentially modulate alpha-L-Arabinofuranosidase activities in antisense 1-aminocyclopropane-1-carboxylic acid synthase tomato pericarp discs.

    PubMed

    Sozzi, Gabriel O; Greve, L Carl; Prody, Gerry A; Labavitch, John M

    2002-07-01

    Alpha-L-Arabinofuranosidases (alpha-Afs) are plant enzymes capable of releasing terminal arabinofuranosyl residues from cell wall matrix polymers, as well as from different glycoconjugates. Three different alpha-Af isoforms were distinguished by size exclusion chromatography of protein extracts from control tomatoes (Lycopersicon esculentum) and an ethylene synthesis-suppressed (ESS) line expressing an antisense 1-aminocyclopropane-1-carboxylic synthase transgene. alpha-Af I and II are active throughout fruit ontogeny. alpha-Af I is the first Zn-dependent cell wall enzyme isolated from tomato pericarp tissues, thus suggesting the involvement of zinc in fruit cell wall metabolism. This isoform is inhibited by 1,10-phenanthroline, but remains stable in the presence of NaCl and sucrose. alpha-Af II activity accounts for over 80% of the total alpha-Af activity in 10-d-old fruit, but activity drops during ripening. In contrast, alpha-Af III is ethylene dependent and specifically active during ripening. alpha-Af I released monosaccharide arabinose from KOH-soluble polysaccharides from tomato cell walls, whereas alpha-Af II and III acted on Na(2)CO(3)-soluble pectins. Different alpha-Af isoform responses to gibberellic acid, synthetic auxins, and ethylene were followed by using a novel ESS mature-green tomato pericarp disc system. alpha-Af I and II activity increased when gibberellic acid or 2,4-dichlorophenoxyacetic acid was applied, whereas ethylene treatment enhanced only alpha-Af III activity. Results suggest that tomato alpha-Afs are encoded by a gene family under differential hormonal controls, and probably have different in vivo functions. The ESS pericarp explant system allows comprehensive studies involving effects of physiological levels of different growth regulators on gene expression and enzyme activity with negligible wound-induced ethylene production.

  16. EDTA chelation therapy, without added vitamin C, decreases oxidative DNA damage and lipid peroxidation.

    PubMed

    Roussel, Anne Marie; Hininger-Favier, Isabelle; Waters, Robert S; Osman, Mireille; Fernholz, Karen; Anderson, Richard A

    2009-03-01

    Chelation therapy is thought to not only remove contaminating metals but also to decrease free radical production. However, in standard ethylene diamine tetracetic acid (EDTA) chelation therapy, high doses of vitamin C with potential pro-oxidant effects are often added to the chelation solution. The authors demonstrated previously that the intravenous administration of the standard chelation cocktail, containing high amounts of vitamin C, resulted in an acute transitory pro-oxidant burst that should be avoided in the treatment of pathologies at risk of increased oxidative stress such as diabetes and cardiovascular disease. The current study was designed to determine the acute and chronic biochemical effects of chelation therapy on accepted clinical, antioxidant variables. An EDTA chelation cocktail not containing ascorbic acid was administered to six adult patients for five weeks (10 sessions of chelation therapy); antioxidant indicators were monitored. Immediately after the initial chelation session, in contrast with the data previously reported with the standard cocktail containing high doses of vitamin C, none of the oxidative stress markers were adversely modified. After five weeks, plasma peroxide levels, monitored by malondialdehyde, decreased by 20 percent, and DNA damage, monitored by formamidopyrimidine-DNA glycosylase (Fpg) sensitive sites, decreased by 22 percent. Remaining antioxidant-related variables did not change. In summary, this study demonstrates that multiple sessions of EDTA chelation therapy in combination with vitamins and minerals, but without added ascorbic acid, decreases oxidative stress. These results should be beneficial in the treatment of diseases associated with increased oxidative stress such as diabetes and cardiovascular diseases.

  17. Mechanism of hydrofluoric acid formation in ethylene carbonate electrolytes with fluorine salt additives

    NASA Astrophysics Data System (ADS)

    Tebbe, Jonathon L.; Fuerst, Thomas F.; Musgrave, Charles B.

    2015-11-01

    We utilized density functional theory to examine HF generation in lithium-ion battery electrolytes from reactions between H2O and the decomposition products of three electrolyte additives: LiPF6, LiPOF4, and LiAsF6. Decomposition of these additives produces PF5, AsF5, and POF3 along with LiF precipitates. We found PF5 and AsF5 react with H2O in two sequential steps to form two HF molecules and POF3 and AsOF3, respectively. PF5 (or AsF5) complexes with H2O and undergoes ligand exchange to form HF and PF4OH (AsF4OH) with an activation barrier of 114.2 (30.5) kJ mol-1 and reaction enthalpy of 14.6 (-11.3) kJ mol-1. The ethylene carbonate (EC) electrolyte forms a Lewis acid-base complex with the PF4OH (AsF4OH) product, reducing the barrier to HF formation. Reactions of POF3 were examined and are not characterized by complexation of POF3 with H2O or EC, while PF5 and AsF5 complex favorably with H2O and EC. HF formation from POF3 occurs with a reaction enthalpy of -3.8 kJ mol-1 and a 157.7 kJ mol-1 barrier, 43.5 kJ mol-1 higher than forming HF from PF5. HF generation in electrolytes employing LiPOF4 should be significantly lower than those using LiPF6 or LiAsF6 and LiPOF4 should be further investigated as an alternative electrolyte additive.

  18. Impact of brassinosteroids and ethylene on ascorbic acid accumulation in tomato leaves.

    PubMed

    Mazorra Morales, Luis Miguel; Senn, María Eugenia; Gergoff Grozeff, Gustavo Esteban; Fanello, Diego Darío; Carrión, Cristian Antonio; Núñez, Miriam; Bishop, Gerard James; Bartoli, Carlos Guillermo

    2014-01-01

    Plant steroid hormones brassinosteroids (BRs) and the gaseous hormone ethylene (ET) alter the ascorbic acid-glutathione (AA-GSH) levels in tomato (Solanum lycopersicum L.) plants. The interaction of these hormones in regulating antioxidant metabolism is however unknown. The combined use of genetics (BR-mutants) and chemical application (BR/ET-related chemicals) shows that BRs and ET signalling pathways interact, to regulate leaf AA content and synthesis. BR-deficient (d(x)) leaves display low total AA but BR-accumulating (35S:D) leaves show normal total AA content. Leaves with either BR levels lower or higher than wild type plants showed a higher oxidised AA redox state. The activity of L-galactono-1,4-lactone dehydrogenase (L-GalLDH), the mitochondrial enzyme that catalyses the last step in AA synthesis is lower in d(x) and higher in 35S:D plants. BR-deficient mutants show higher ET production but it is restored to normal levels when BR content is increased in 35S:D plants. Suppression of ET signalling using 1-methylcyclopropene in d(x) and 35S:D plants restored leaf AA content and L-GalLDH activity, to the values observed in wild type. The suppression of ET action in d(x) and 35S:D leaves leads to the respective decreasing and increasing respiration, indicating an opposite response compared to AA synthesis. This inverse relationship is lacking in ET suppressed d(x) plants in response to external BRs. The modifications in the in vivo activity of L-GalLDH activity do not correlate with changes in the level of the enzyme. Taken together, these data suggest that ET suppresses and BRs promote AA synthesis and accumulation.

  19. Alleviation of salt-induced photosynthesis and growth inhibition by salicylic acid involves glycinebetaine and ethylene in mungbean (Vigna radiata L.).

    PubMed

    Khan, M Iqbal R; Asgher, M; Khan, Nafees A

    2014-07-01

    The influence of salicylic acid (SA) in alleviation of salt stress in mungbean (Vigna radiata L.) through modulation of glycinebetaine (GB) and ethylene was studied. SA application at 0.5 mM increased methionine (Met) and GB accumulation in plants concomitant with the suppression of ethylene formation by inhibiting 1-aminocyclopropane carboxylic acid synthase (ACS) activity more conspicuously under salt stress than no stress. The increased GB accumulation together with reduced ethylene under salt stress by SA application was associated with increased glutathione (GSH) content and lower oxidative stress. These positive effects on plant metabolism induced by SA application led to improved photosynthesis and growth under salt stress. These results suggest that SA induces GB accumulation through increased Met and suppresses ethylene formation under salt stress and enhances antioxidant system resulting in alleviation of adverse effects of salt stress on photosynthesis and growth. These effects of SA were substantiated by the findings that application of SA-analogue, 2, 6, dichloro-isonicotinic acid (INA) and ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG) resulted in similar effects on Met, GB, ethylene production, photosynthesis and growth under salt stress. Future studies on the interaction between SA, GB and ethylene could be exploited for adaptive responses of plants under salt stress.

  20. Photocatalytic oxidation of cadmium-EDTA with titanium dioxide

    SciTech Connect

    Davis, A.P.; Green, D.L.

    1999-02-15

    Ethylenediaminetetraacetic acid (EDTA) forms stable complexes with toxic metals such as cadmium. Metal-EDTA chelates are chemically stable and occur in a number of waste situations. The viability of using photocatalytic oxidation with titanium dioxide to degrade Cd-EDTA was examined at concentrations from 2 {times} 10{sup {minus}5} to 10{sup {minus}3} M at pH from 3 to 8. Initially a portion of the complex was adsorbed onto the TiO{sub 2} photocatalyst at low pH. However, independent of the degree of initial adsorption, Cd-EDTA was rapidly destroyed with little dependence on pH. Concurrently, in most cases cadmium was liberated as Cd{sup 2+} with no affiliation with organic reaction products; its fate depended on suspension pH. At low pH, Cd{sub aq}{sup 2+} was released into solution. Also, organic carbon was released into solution as oxidation of adsorbed EDTA occurred. At higher pH the Cd was adsorbed onto the TiO{sub 2} at adsorption equilibrium levels. Major products detected include formaldehyde, formic acid, and acetic acid. Nitrate and glyoxylic, malonic, and oxalic acids were detected, but concentrations were low. The incomplete carbon balance and the lack of nitrate production suggest the production of organic amines from the degradation of Cd-EDTA. Release of the Cd as Cd{sup 2+} occurs after mineralization of only about half of the organic carbon.

  1. Reversal of Vascular Calcification and Aneurysms in a Rat Model Using Dual Targeted Therapy with EDTA- and PGG-Loaded Nanoparticles

    PubMed Central

    Nosoudi, Nasim; Chowdhury, Aniqa; Siclari, Steven; Karamched, Saketh; Parasaram, Vaideesh; Parrish, Joe; Gerard, Patrick; Vyavahare, Narendra

    2016-01-01

    Degeneration of elastic lamina and vascular calcification are common features of vascular pathology such as aortic aneurysms. We tested whether dual therapy with targeted nanoparticles (NPs) can remove mineral deposits (by delivery of a chelating agent, ethylene diamine tetraacetic acid (EDTA)) and restore elastic lamina (by delivery of a polyphenol, pentagalloyl glucose (PGG)) to reverse moderate aneurysm development. EDTA followed by PGG NP delivery led to reduction in macrophage recruitment, matrix metalloproteinase (MMP) activity, elastin degradation and calcification in the aorta as compared to delivery of control blank NPs. Such dual therapy restored vascular elastic lamina and improved vascular function as observed by improvement in circumferential strain. Therefore, dual targeted therapy may be an attractive option to remove mineral deposits and restore healthy arterial structures in moderately developed aneurysms. PMID:27698934

  2. Reversal of Vascular Calcification and Aneurysms in a Rat Model Using Dual Targeted Therapy with EDTA- and PGG-Loaded Nanoparticles

    PubMed Central

    Nosoudi, Nasim; Chowdhury, Aniqa; Siclari, Steven; Karamched, Saketh; Parasaram, Vaideesh; Parrish, Joe; Gerard, Patrick; Vyavahare, Narendra

    2016-01-01

    Degeneration of elastic lamina and vascular calcification are common features of vascular pathology such as aortic aneurysms. We tested whether dual therapy with targeted nanoparticles (NPs) can remove mineral deposits (by delivery of a chelating agent, ethylene diamine tetraacetic acid (EDTA)) and restore elastic lamina (by delivery of a polyphenol, pentagalloyl glucose (PGG)) to reverse moderate aneurysm development. EDTA followed by PGG NP delivery led to reduction in macrophage recruitment, matrix metalloproteinase (MMP) activity, elastin degradation and calcification in the aorta as compared to delivery of control blank NPs. Such dual therapy restored vascular elastic lamina and improved vascular function as observed by improvement in circumferential strain. Therefore, dual targeted therapy may be an attractive option to remove mineral deposits and restore healthy arterial structures in moderately developed aneurysms.

  3. Ethylene insensitive plants

    DOEpatents

    Ecker, Joseph R.; Nehring, Ramlah; McGrath, Robert B.

    2007-05-22

    Nucleic acid and polypeptide sequences are described which relate to an EIN6 gene, a gene involved in the plant ethylene response. Plant transformation vectors and transgenic plants are described which display an altered ethylene-dependent phenotype due to altered expression of EIN6 in transformed plants.

  4. Determination of hydrogen ion by ion chromatography (IC) with sulfonated cation-exchange resin as the stationary phase and aqueous EDTA (ethylenediamine-N,N,N',N'-tetraacetic acid) solution as the mobile phase.

    PubMed

    Hu, W; Iles, A; Hasebe, K; Matsukami, H; Cao, S; Tanaka, K

    2001-05-01

    An ion chromatographic (IC) method has been developed for determination of hydrogen ion (H+). It is based on the use of sulfonated cation-exchange resin as stationary phase, aqueous ethylenediamine-N,N,N',N'-tetraacetic acid (dipotassium salt, EDTA-2K, written as K2H2Y) solution as mobile phase, and conductivity for detection. H+ was separated mainly by cation-exchange, but its elution was accelerated by the presence of EDTA. The order of elution for the model cations was H+ > Li+ > Na+ > NH4+ > Ca2+ > > Mg2+. A sharp and highly symmetrical peak was obtained for H+ and this was attributed to the capacity of H2Y2(2-) to receive and bind H+. H+ was detected conductiometrically and detector response (reduction in conductivity as a result of H+ +H2Y2- --> H3Y-) was linearly proportional to the concentration of H+ in the sample. The detection limit for H+ with this IC system was better than 4.7 micromol L(-1). A significant advantage of this method was the ability to separate and determine, in one step, H+ and other cations. The successful determination of H+ and other cation species in real acid-rain samples demonstrated the usefulness of this method.

  5. Poly(ethylene glycol)-co-methacrylamide-co-acrylic acid based nanogels for delivery of doxorubicin.

    PubMed

    Kumar, Parveen; Behl, Gautam; Sikka, Manisha; Chhikara, Aruna; Chopra, Madhu

    2016-10-01

    Polymeric nanogels have been widely explored for their potential application as delivery carriers for cancer therapeutics. The ability of nanogels to encapsulate therapeutics by simple diffusion mechanism and the ease of their fabrication to impart target specificity in addition to their ability to get internalized into target cells make them good candidates for drug delivery. The present study aims to investigate the applicability of poly(ethylene glycol)-co-methacrylamide-co-acrylic acid (PMA)-based nanogels as a viable option for the delivery of doxorubicin (DOX). The nanogels were synthesized by free radical polymerization in an inverse mini-emulsion and characterized by nuclear magnetic resonance spectroscopy ((1)H NMR), Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction and differential scanning calorimetry. DOX was physically incorporated into the nanogels (PMA-DOX) and the mechanism of its in vitro release was studied. TEM experiment revealed spherical morphology of nanogels and the hydrodynamic diameter of the neat nanogels was in the range of 160 ± 46.95 nm. The size of the nanogels increased from 235.1 ± 28.46 to 403.7 ± 89.89 nm with the increase in drug loading capacity from 4.68 ± 0.03 to 13.71 ± 0.01%. The sustained release of DOX was observed upto 80 h and the release rate decreased with increased loading capacity following anomalous release mechanism as indicated by the value of diffusion exponent (n = 0.64-0.75) obtained from Korsmeyer-Peppas equation. Further, cytotoxicity evaluation of PMA-DOX nanogels on HeLa cells resulted in relatively higher efficacy (IC50~5.88 μg/mL) as compared to free DOX (IC50~7.24 μg/mL) thus demonstrating that the preparation is potentially a promising drug delivery carrier.

  6. Effect of Ethephon, Indole Butyric Acid, and Treatment Solution pH on Rooting and on Ethylene Levels within Mung Bean Cuttings.

    PubMed

    Mudge, K W; Swanson, B T

    1978-02-01

    Light-grown mung bean (Phaseolus aureus Roxb.) cuttings were treated with buffered and nonbuffered solutions of Ethephon, indole butyric acid (IBA), and the combination of both. Ethephon treatment resulted in increased tissue ethylene levels with increasing solution pH, but had no effect on rooting. IBA treatment had no effect on tissue ethylene levels, but strongly promoted rooting. Combinations of Ethephon and IBA had no effect on rooting of mung bean cuttings beyond that obtained by IBA alone. PMID:16660274

  7. Antisense suppression of phospholipase D alpha retards abscisic acid- and ethylene-promoted senescence of postharvest Arabidopsis leaves.

    PubMed

    Fan, L; Zheng, S; Wang, X

    1997-12-01

    Membrane disruption has been proposed to be a key event in plant senescence, and phospholipase D (PLD; EC 3.1.4.4) has been thought to play an important role in membrane deterioration. We recently cloned and biochemically characterized three different PLDs from Arabidopsis. In this study, we investigated the role of the most prevalent phospholipid-hydrolyzing enzyme, PLD alpha, in membrane degradation and senescence in Arabidopsis. The expression of PLD alpha was suppressed by introducing a PLD alpha antisense cDNA fragment into Arabidopsis. When incubated with abscisic acid and ethylene, leaves detached from the PLD alpha-deficient transgenic plants showed a slower rate of senescence than did those from wild-type and transgenic control plants. The retardation of senescence was demonstrated by delayed leaf yellowing, lower ion leakage, greater photosynthetic activity, and higher content of chlorophyll and phospholipids in the PLD alpha antisense leaves than in those of the wild type. Treatment of detached leaves with abscisic acid and ethylene stimulated PLD alpha expression, as indicated by increases in PLD alpha mRNA, protein, and activity. In the absence of abscisic acid and ethylene, however, detached leaves from the PLD alpha-deficient and wild-type plants showed a similar rate of senescence. In addition, the suppression of PLD alpha did not alter natural plant growth and development. These data suggest that PLD alpha is an important mediator in phytohormone-promoted senescence in detached leaves but is not a direct promoter of natural senescence. The physiological relevance of these findings is discussed.

  8. Synergistic enhancement of ethylene production and germination with kinetin and 1-aminocyclopropane-1-carboxylic Acid in lettuce seeds exposed to salinity stress.

    PubMed

    Khan, A A; Huang, X L

    1988-08-01

    Relief of salt (0.1 molar NaCl) stress on germination of lettuce (Lactuca sativa L., cv Mesa 659) seeds occurred with applications of 0.05 millimolar kinetin (KIN) and 1 to 10 millimolar 1-aminocyclopropane 1-carboxylic acid (ACC). Treatment with KIN enhanced the pregermination ethylene production under saline condition. A synergistic or an additive enhancement of pregermination ethylene production and germination occurred under saline condition in the presence of KIN and a saturating dose (10 millimolar) of ACC. No KIN-ACC synergism was noted in ethylene production or germination under nonsaline condition. Addition of 1 millimolar aminoethoxyvinylglycine (AVG) inhibited the KIN-enhanced pregermination ethylene production (85 to 89%) and germination (58%) under saline condition but not the synergistic effect of KIN + ACC on ethylene production. Under nonsaline condition, AVG had no effect on germination even though ethylene production was strongly inhibited. Alleviation of salt stress by KIN was inhibited in a competitive manner by 2,5-norbornadiene (NBD) (0.02-0.2 milliliter per liter), and the addition of ACC and/or ethylene reduced this inhibition. An increase in the pregermination ethylene production and germination occurred also by cotylenin E (CN) under saline condition. However, neither AVG (1 millimolar) nor NBD (0.02 to 0.2 milliliter per liter) prevented the relief of salt stress by CN. Thus, KIN may alleviate salt stress on germination by promoting both ACC production and its conversion to ethylene. Rapid utilization of ACC may be the basis for the synergistic or the additive effect of KIN plus ACC. The need for ethylene production and action for the relief of salt stress is circumvented by a treatment with CN.

  9. Sodium iron EDTA and ascorbic acid, but not polyphenol oxidase treatment, counteract the strong inhibitory effect of polyphenols from brown sorghum on the absorption of fortification iron in young women.

    PubMed

    Cercamondi, Colin I; Egli, Ines M; Zeder, Christophe; Hurrell, Richard F

    2014-02-01

    In addition to phytate, polyphenols (PP) might contribute to low Fe bioavailability from sorghum-based foods. To investigate the inhibitory effects of sorghum PP on Fe absorption and the potential enhancing effects of ascorbic acid (AA), NaFeEDTA and the PP oxidase enzyme laccase, we carried out three Fe absorption studies in fifty young women consuming dephytinised Fe-fortified test meals based on white and brown sorghum varieties with different PP concentrations. Fe absorption was measured as the incorporation of stable Fe isotopes into erythrocytes. In study 1, Fe absorption from meals with 17 mg PP (8·5%) was higher than that from meals with 73 mg PP (3·2%) and 167 mg PP (2·7%; P< 0·001). Fe absorption from meals containing 73 and 167 mg PP did not differ (P= 0·9). In study 2, Fe absorption from NaFeEDTA-fortified meals (167 mg PP) was higher than that from the same meals fortified with FeSO₄ (4·6 v. 2·7%; P< 0·001), but still it was lower than that from FeSO₄-fortified meals with 17 mg PP (10·7%; P< 0·001). In study 3, laccase treatment decreased the levels of PP from 167 to 42 mg, but it did not improve absorption compared with that from meals with 167 mg PP (4·8 v. 4·6%; P= 0·4), whereas adding AA increased absorption to 13·6% (P< 0·001). These findings suggest that PP from brown sorghum contribute to low Fe bioavailability from sorghum foods and that AA and, to a lesser extent, NaFeEDTA, but not laccase, have the potential to overcome the inhibitory effect of PP and improve Fe absorption from sorghum foods.

  10. Iron bioavailability from a lipid-based complementary food fortificant mixed with millet porridge can be optimized by adding phytase and ascorbic acid but not by using a mixture of ferrous sulfate and sodium iron EDTA.

    PubMed

    Cercamondi, Colin I; Egli, Ines M; Mitchikpe, Evariste; Tossou, Felicien; Hessou, Joamel; Zeder, Christophe; Hounhouigan, Joseph D; Hurrell, Richard F

    2013-08-01

    Home fortification with lipid-based nutrient supplements (LNSs) is a promising approach to improve bioavailable iron and energy intake of young children in developing countries. To optimize iron bioavailability from an LNS named complementary food fortificant (CFF), 3 stable isotope studies were conducted in 52 young Beninese children. Test meals consisted of millet porridge mixed with CFF and ascorbic acid (AA). Study 1 compared iron absorption from FeSO4-fortifed meals with meals fortified with a mixture of FeSO4 and NaFeEDTA. Study 2 compared iron absorption from FeSO4-fortifed meals without or with extra AA. Study 3 compared iron absorption from FeSO4-fortified meals with meals containing phytase added prior to consumption, once without or once with extra AA. Iron absorption was measured as erythrocyte incorporation of stable isotopes. In study 1, iron absorption from FeSO4 (8.4%) was higher than that from the mixture of NaFeEDTA and FeSO4 (5.9%; P < 0.05). In study 2, the extra AA increased absorption (11.6%) compared with the standard AA concentration (7.3%; P < 0.001). In study 3, absorption from meals containing phytase without or with extra AA (15.8 and 19.9%, respectively) increased compared with meals without phytase (8.0%; P < 0.001). The addition of extra AA to meals containing phytase increased absorption compared with the test meals containing phytase without extra AA (P < 0.05). These findings suggest that phytase and AA, and especially a combination of the two, but not a mixture of FeSO4 and NaFeEDTA would be useful strategies to increase iron bioavailability from a CFF mixed with cereal porridge.

  11. Poly(ethylene glycol) (PEG)-lactic acid nanocarrier-based degradable hydrogels for restoring the vaginal microenvironment.

    PubMed

    Sundara Rajan, Sujata; Turovskiy, Yevgeniy; Singh, Yashveer; Chikindas, Michael L; Sinko, Patrick J

    2014-11-28

    Women with bacterial vaginosis (BV) display reduced vaginal acidity, which make them susceptible to associated infections such as HIV. In the current study, poly(ethylene glycol) (PEG) nanocarrier-based degradable hydrogels were developed for the controlled release of lactic acid in the vagina of BV-infected women. PEG-lactic acid (PEG-LA) nanocarriers were prepared by covalently attaching lactic acid to 8-arm PEG-SH via cleavable thioester bonds. PEG-LA nanocarriers with 4 copies of lactic acid per molecule provided controlled release of lactic acid with a maximum release of 23% and 47% bound lactic acid in phosphate buffered saline (PBS, pH7.4) and acetate buffer (AB, pH4.3), respectively. The PEG nanocarrier-based hydrogels were formed by cross-linking the PEG-LA nanocarriers with 4-arm PEG-NHS via degradable thioester bonds. The nanocarrier-based hydrogels formed within 20 min under ambient conditions and exhibited an elastic modulus that was 100-fold higher than the viscous modulus. The nanocarrier-based degradable hydrogels provided controlled release of lactic acid for several hours; however, a maximum release of only 10%-14% bound lactic acid was observed possibly due to steric hindrance of the polymer chains in the cross-linked hydrogel. In contrast, hydrogels with passively entrapped lactic acid showed burst release with complete release within 30 min. Lactic acid showed antimicrobial activity against the primary BV pathogen Gardnerella vaginalis with a minimum inhibitory concentration (MIC) of 3.6 mg/ml. In addition, the hydrogels with passively entrapped lactic acid showed retained antimicrobial activity with complete inhibition G. vaginalis growth within 48 h. The results of the current study collectively demonstrate the potential of PEG nanocarrier-based hydrogels for vaginal administration of lactic acid for preventing and treating BV.

  12. Analysis and environmental fate of EDTA and ETPA

    SciTech Connect

    Sillanpaeae, M.

    1997-10-24

    In this thesis, analytical techniques for the determination of two metal complexing agents, EDTA and DTPA, in aquatic environments were investigated with the main emphasis on the pulp and paper mill waste waters and the receiving natural waters. These compounds are widely used as metal chelating agents in industry. The behavior of EDTA and DTPA in waste waters and in the natural aquatic environment was investigated. In addition, the impact of EDTA and DTPA on heavy metal toxicity was studied. The thesis consists of a literature survey deals with the analytical methods developed for the determination of these aminopolycarboxylic acids. The review consists of a critical comparison of the advantages and disadvantages of chromatographic, electrochemical, spectrophotometric, titrimetric and atomic absorption methods for their applicability to the determination of EDTA and DTPA in waste and natural waters.

  13. Salicylic acid alleviates adverse effects of heat stress on photosynthesis through changes in proline production and ethylene formation

    PubMed Central

    Khan, M Iqbal R; Iqbal, Noushina; Masood, Asim; Per, Tasir S; Khan, Nafees A

    2013-01-01

    We investigated the potential of salicylic acid (SA) in alleviating the adverse effects of heat stress on photosynthesis in wheat (Triticum aestivum L.) cv WH 711. Activity of ribulose 1,5-bisphosphate carboxylase (Rubisco), photosynthetic-nitrogen use efficiency (NUE), and net photosynthesis decreased in plants subjected to heat stress (40°C for 6 h), but proline metabolism increased. SA treatment (0.5 mM) alleviated heat stress by increasing proline production through the increase in γ-glutamyl kinase (GK) and decrease in proline oxidase (PROX) activity, resulting in promotion of osmotic potential and water potential necessary for maintaining photosynthetic activity. Together with this, SA treatment restricted the ethylene formation in heat-stressed plants to optimal range by inhibiting activity of 1-aminocyclopropane carboxylic acid (ACC) synthase (ACS). This resulted in improved proline metabolism, N assimilation and photosynthesis. The results suggest that SA interacts with proline metabolism and ethylene formation to alleviate the adverse effects of heat stress on photosynthesis in wheat. PMID:24022274

  14. Salicylic acid alleviates adverse effects of heat stress on photosynthesis through changes in proline production and ethylene formation.

    PubMed

    Khan, M Iqbal R; Iqbal, Noushina; Masood, Asim; Per, Tasir S; Khan, Nafees A

    2013-11-01

    We investigated the potential of salicylic acid (SA) in alleviating the adverse effects of heat stress on photosynthesis in wheat (Triticum aestivum L.) cv WH 711. Activity of ribulose 1,5-bisphosphate carboxylase (Rubisco), photosynthetic-nitrogen use efficiency (NUE), and net photosynthesis decreased in plants subjected to heat stress (40 °C for 6 h), but proline metabolism increased. SA treatment (0.5 mM) alleviated heat stress by increasing proline production through the increase in γ-glutamyl kinase (GK) and decrease in proline oxidase (PROX) activity, resulting in promotion of osmotic potential and water potential necessary for maintaining photosynthetic activity. Together with this, SA treatment restricted the ethylene formation in heat-stressed plants to optimal range by inhibiting activity of 1-aminocyclopropane carboxylic acid (ACC) synthase (ACS). This resulted in improved proline metabolism, N assimilation and photosynthesis. The results suggest that SA interacts with proline metabolism and ethylene formation to alleviate the adverse effects of heat stress on photosynthesis in wheat.

  15. Antagonism between abscisic acid and ethylene in Arabidopsis acts in parallel with the reciprocal regulation of their metabolism and signaling pathways.

    PubMed

    Cheng, Wan-Hsing; Chiang, Ming-Hau; Hwang, San-Gwang; Lin, Pei-Chi

    2009-09-01

    Although abscisic acid (ABA) and ethylene have antagonistic functions in the control of plant growth and development, including seed germination and early seedling development, it remains unknown whether a convergent point exists between these two signaling pathways or whether they operate in parallel in Arabidopsis thaliana. To elucidate this issue, four ethylene mutants, ctr1, ein2, ein3, and ein6, were crossed with aba2 (also known as gin1-3) to generate double mutants. Genetic epistasis analysis revealed that all of the resulting double mutants displayed aba2 mutant phenotypes with a small plant size and wiltiness when grown in soil or on agar plates. Further ethylene sensitivity or triple response analyses demonstrated that these double mutants also retained the ctr1 or ein mutant phenotypes, showing ethylene constitutive triple and insensitive responses, respectively. Our current data therefore demonstrate that ABA and ethylene act in parallel, at least in primary signal transduction pathways. Moreover, by microarray analysis we found that an ACC oxidase (ACO) was significantly upregulated in the aba2 mutant, whereas the 9-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3) gene in ein2 was upregulated, and both the ABSCISIC ACID INSENSITIVE1 (ABI1) and cytochrome P450, family 707, subfamily A, polypeptide 2 (CYP707A2) genes in etr1-1 were downregulated. These data further suggest that ABA and ethylene may control the hormonal biosynthesis, catabolism, or signaling of each other to enhance their antagonistic effects upon seed germination and early seedling growth.

  16. Dissecting the role of climacteric ethylene in kiwifruit (Actinidia chinensis) ripening using a 1-aminocyclopropane-1-carboxylic acid oxidase knockdown line.

    PubMed

    Atkinson, Ross G; Gunaseelan, Kularajathevan; Wang, Mindy Y; Luo, Luke; Wang, Tianchi; Norling, Cara L; Johnston, Sarah L; Maddumage, Ratnasiri; Schröder, Roswitha; Schaffer, Robert J

    2011-07-01

    During climacteric fruit ripening, autocatalytic (Type II) ethylene production initiates a transcriptional cascade that controls the production of many important fruit quality traits including flavour production and softening. The last step in ethylene biosynthesis is the conversion of 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene by the enzyme ACC oxidase (ACO). Ten independent kiwifruit (Actinidia chinensis) lines were generated targeting suppression of fruit ripening-related ACO genes and the fruit from one of these lines (TK2) did not produce detectable levels of climacteric ethylene. Ripening behaviour in a population of kiwifruit at harvest is asynchronous, so a short burst of exogenous ethylene was used to synchronize ripening in TK2 and control fruit. Following such a treatment, TK2 and control fruit softened to an 'eating-ripe' firmness. Control fruit produced climacteric ethylene and softened beyond eating-ripe by 5 d. In contrast, TK2 fruit maintained an eating-ripe firmness for >25 d and total volatile production was dramatically reduced. Application of continuous exogenous ethylene to the ripening-arrested TK2 fruit re-initiated fruit softening and typical ripe fruit volatiles were detected. A 17 500 gene microarray identified 401 genes that changed after ethylene treatment, including a polygalacturonase and a pectate lyase involved in cell wall breakdown, and a quinone oxidoreductase potentially involved in volatile production. Many of the gene changes were consistent with the softening and flavour changes observed after ethylene treatment. However, a surprisingly large number of genes of unknown function were also observed, which could account for the unique flavour and textural properties of ripe kiwifruit.

  17. 21 CFR 172.135 - Disodium EDTA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Disodium EDTA. 172.135 Section 172.135 Food and... Preservatives § 172.135 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-tate... following foods at not to exceed the levels prescribed, calculated as anhydrous calcium disodium EDTA:...

  18. 21 CFR 172.135 - Disodium EDTA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Disodium EDTA. 172.135 Section 172.135 Food and... Preservatives § 172.135 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-tate... following foods at not to exceed the levels prescribed, calculated as anhydrous calcium disodium EDTA:...

  19. Expression of the ethylene response factor gene TSRF1 enhances abscisic acid responses during seedling development in tobacco.

    PubMed

    Zhang, Hongbo; Yang, Yuhong; Zhang, Zhijin; Chen, Jia; Wang, Xue-Chen; Huang, Rongfeng

    2008-10-01

    Ethylene response factor (ERF) proteins function as multiple regulators in the interaction of different stress-responsive pathways. During investigating the interaction of ethylene and abscisic acid (ABA) pathways, several GCC-box-binding repressors of ERF proteins have been reported to repress both ethylene- and ABA-related responses, but it is unclear how GCC-box-binding activator ERF proteins are involved in this interaction. Previously, we isolated an ERF protein tomato stress-responsive factor 1 (TSRF1) from tomato by yeast one hybrid, and showed that TSRF1 as a transcriptional activator physically interacts with GCC box, and activates the expression of GCC box-containing genes and enhances resistance to pathogens, while ABA treatment alters the binding ability of TSRF1 with this element and decreases resistance to pathogen Ralstonia solanacearum. Here, we further report that TSRF1 is able to interact with a GCC box-like sequence (indicated as CE1/GCC in this paper) containing the core sequence of ZmABI4-binding-CE1-like element, and regulates ABA responses. Overexpression of TSRF1 in tobacco enhances ABA sensitivity during germination, cotyledon expansion and root elongation. Biochemical and molecular analyses demonstrate that TSRF1 interacts with CE1/GCC. Importantly, ABA treatment enhances the interaction of TSRF1 with the ABA-responsive element and subsequently increasing the expression of ABA-responsive or CE1/GCC-containing genes. In addition, TSRF1 also promotes the expression of senescence-associated genes and tobacco seedling senescence in response to ABA. These results show that TSRF1, a GCC-box-binding activator in plant pathogen resistance, positively regulates ABA-related plant developmental processes.

  20. An Ancestral Role for CONSTITUTIVE TRIPLE RESPONSE1 Proteins in Both Ethylene and Abscisic Acid Signaling1[OPEN

    PubMed Central

    Yasumura, Yuki; Pierik, Ronald; Kelly, Steven; Sakuta, Masaaki; Voesenek, Laurentius A.C.J.; Harberd, Nicholas P.

    2015-01-01

    Land plants have evolved adaptive regulatory mechanisms enabling the survival of environmental stresses associated with terrestrial life. Here, we focus on the evolution of the regulatory CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) component of the ethylene signaling pathway that modulates stress-related changes in plant growth and development. First, we compare CTR1-like proteins from a bryophyte, Physcomitrella patens (representative of early divergent land plants), with those of more recently diverged lycophyte and angiosperm species (including Arabidopsis [Arabidopsis thaliana]) and identify a monophyletic CTR1 family. The fully sequenced P. patens genome encodes only a single member of this family (PpCTR1L). Next, we compare the functions of PpCTR1L with that of related angiosperm proteins. We show that, like angiosperm CTR1 proteins (e.g. AtCTR1 of Arabidopsis), PpCTR1L modulates downstream ethylene signaling via direct interaction with ethylene receptors. These functions, therefore, likely predate the divergence of the bryophytes from the land-plant lineage. However, we also show that PpCTR1L unexpectedly has dual functions and additionally modulates abscisic acid (ABA) signaling. In contrast, while AtCTR1 lacks detectable ABA signaling functions, Arabidopsis has during evolution acquired another homolog that is functionally distinct from AtCTR1. In conclusion, the roles of CTR1-related proteins appear to have functionally diversified during land-plant evolution, and angiosperm CTR1-related proteins appear to have lost an ancestral ABA signaling function. Our study provides new insights into how molecular events such as gene duplication and functional differentiation may have contributed to the adaptive evolution of regulatory mechanisms in plants. PMID:26243614

  1. Mode of Action: Oxalate Crystal-Induced Renal Tubule Degeneration and Glycolic Acid-Induced Dysmorphogenesis—Renal and Developmental Effects of Ethylene Glycol

    SciTech Connect

    Corley, Rick A.; Meek, M E.; Carney, E W.

    2005-10-01

    Ethylene glycol can cause both renal and developmental toxicity, with metabolism playing a key role in the mode of action (MOA) for each form of toxicity. Renal toxicity is ascribed to the terminal metabolite oxalic acid, which precipitates in the kidney in the form of calcium oxalate crystals and is believed to cause physical damage to the renal tubules. The human relevance of the renal toxicity of ethylene glycol is indicated by the similarity between animals and humans of metabolic pathways, the observation of renal oxalate crystals in toxicity studies in experimental animals and human poisonings, and cases of human kidney and bladder stones related to dietary oxalates and oxalate precursors. High-dose gavage exposures to ethylene glycol also cause axial skeletal defects in rodents (but not rabbits), with the intermediary metabolite, glycolic acid, identified as the causative agent. However, the mechanism by which glycolic acid perturbs development has not been investigated sufficiently to develop a plausible hypothesis of mode of action, nor have any cases of ethylene glycol-induced developmental effects been reported in humans. Given this, and the variations in sensitivity between animal species in response, the relevance to humans of ethylene glycol-induced developmental toxicity in animals is unknown at this time.

  2. Spatial and temporal variations in mango colour, acidity, and sweetness in relation to temperature and ethylene gradients within the fruit.

    PubMed

    Nordey, Thibault; Léchaudel, Mathieu; Génard, Michel; Joas, Jacques

    2014-11-01

    Managing fruit quality is complex because many different attributes have to be taken into account, which are themselves subjected to spatial and temporal variations. Heterogeneous fruit quality has been assumed to be partly related to temperature and maturity gradients within the fruit. To test this assumption, we measured the spatial variability of certain mango fruit quality traits: colour of the peel and of the flesh, and sourness and sweetness, at different stages of fruit maturity using destructive methods as well as vis-NIR reflectance. The spatial variability of mango quality traits was compared to internal variations in thermal time, simulated by a physical model, and to internal variations in maturity, using ethylene content as an indicator. All the fruit quality indicators analysed showed significant spatial and temporal variations, regardless of the measurement method used. The heterogeneity of internal fruit quality traits was not correlated with the marked internal temperature gradient we modelled. However, variations in ethylene content revealed a strong internal maturity gradient which was correlated with the spatial variations in measured mango quality traits. Nonetheless, alone, the internal maturity gradient did not explain the variability of fruit quality traits, suggesting that other factors, such as gas, abscisic acid and water gradients, are also involved. PMID:25151123

  3. Improving enzymatic hydrolysis of corn stover pretreated by ethylene glycol-perchloric acid-water mixture.

    PubMed

    He, Yu-Cai; Liu, Feng; Gong, Lei; Lu, Ting; Ding, Yun; Zhang, Dan-Ping; Qing, Qing; Zhang, Yue

    2015-02-01

    To improve the enzymatic saccharification of lignocellulosic biomass, a mixture of ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) was used for pretreating corn stover in this study. After the optimization in oil-bath system, the optimum pretreatment temperature and time were 130 °C and 30 min, respectively. After the saccharification of 10 g/L pretreated corn stover for 48 h, the saccharification rate was obtained in the yield of 77.4 %. To decrease pretreatment temperature and shorten pretreatment time, ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) media under microwave irradiation was employed to pretreat corn stover effectively at 100 °C and 200 W for 5 min. Finally, the recovered hydrolyzates containing glucose obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. These results would be helpful for developing a cost-effective pretreatment combined with enzymatic saccharification of cellulosic materials for the production of lignocellulosic ethanol.

  4. Synthesis of large surface area nano-sized BiVO{sub 4} by an EDTA-modified hydrothermal process and its enhanced visible photocatalytic activity

    SciTech Connect

    Sun Wanting; Xie Mingzheng; Jing Liqiang; Luan Yunbo; Fu Honggang

    2011-11-15

    In this work, monoclinic scheelite-type BiVO{sub 4} nanoparticle with large surface area has been successfully synthesized, using Bi(NO{sub 3}){sub 3} and NH{sub 4}VO{sub 3} as raw materials, through a hydrothermal process in the presence of ethylene diamine tetraacetic acid (EDTA). It is demonstrated that the nanoparticle size of as-prepared BiVO{sub 4} becomes small by decreasing hydrothermal temperature, shortening hydrothermal reaction time and increasing EDTA amount used. The resulting BiVO{sub 4} nanoparticle with large surface area exhibits a good photocatalytic performance for degrading phenol solution as a model organic pollutant under visible illumination. The key of this method is the chelating role of EDTA group in the synthetic process that it can greatly control the concentration of Bi{sup 3+}, leading to the growth inhibition of BiVO{sub 4} crystallite. The work provides a route for the synthesis of Bi-containing nano-sized composite oxides with large surface area. - Graphical abstract: High visible active nano-sized BiVO{sub 4} photocatalyst with large surface area is successfully synthesized, which is attributed to the chelating role of EDTA group inhibiting the growth of BiVO{sub 4} crystallites. Highlights: > Monoclinic scheelite-type BiVO{sub 4} nanoparticle with large surface area has been synthesized by a hydrothermal process. > Key of this method is the chelating role of EDTA group inhibiting the growth of BiVO{sub 4} crystallites. > Resulting nano-sized BiVO{sub 4} exhibits a good photocatalytic activity for degrading phenol under visible illumination.

  5. Melt mixed composites of poly(ethylene-co-methacrylic acid) ionomers and multiwall carbon nanotubes: influence of specific interactions.

    PubMed

    Bose, Suryasarathi; Bhattacharyya, Arup R; Chawley, Manish; Kodgire, Pravin V; Kulkarni, Ajit R; Misra, Ashok; Pötschke, Petra

    2008-04-01

    Multiwall carbon nanotubes (MWNT) were melt-mixed with poly(ethylene-co-methacrylic acid) ionomers (Surlyn) using twin screw microcompounder. The specific interactions existing between the Na+ moieties in Surlyn and the pi electron clouds of MWNT were supported by FTIR and Raman spectroscopic analysis. SAXS scattering patterns were found to be progressively broadened in presence of MWNT in Surlyn/MWNT composites. Morphological investigations revealed selective clustering of MWNT in the vicinity of the ionic domains in Surlyn. Further, the domain size of the ionic clusters was found to increase with increasing MWNT content disrupting the ionic pairs apart in the ionic domain. The melt rheological response of Surlyn was significantly affected in presence of MWNT and was profoundly dependent on the ionic clusters. The state of dispersion of MWNT was assessed by AC electrical conductivity measurements. The associated percolation threshold was observed between 1.5-2 wt% of MWNT.

  6. Thermal Treatment of EDTA Solutions

    SciTech Connect

    Denne, B.

    2006-07-01

    Chemical cleaning of commercial nuclear power facility secondary systems, using EDTA, results in large volumes of chelated liquids requiring some form of treatment prior to disposal. The Nuclear Regulatory Commission regulates the presence of chelates in disposal cells and this paper will look at several methods used to ensure compliance with disposal site criteria. The emphasis of this paper will be on results achieved through thermal treatment of chemical cleaning wastes at the Pacific EcoSolutions' (PEcoS) low level and mixed radioactive waste processing facility in Richland, Washington. We will discuss challenges in transportation, receipt, storage, processing, and disposal associated with EDTA solutions and how those challenges are overcome. (author)

  7. Miscibility of poly(lactic acid) and poly(ethylene oxide) solvent polymer blends and nanofibers made by solution blow spinning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The miscibility of blends of poly(lactic acid) (PLA) and poly(ethylene oxide) (PEO) was studied in polymer solutions by dilute solution viscometry and in solution blow spun nanofibers by microscopy (SEM, TEM) and by thermal and spectral analysis. Three blends of PLA and PEO were solution blended in...

  8. Characterization of an Arabidopsis-Phytophthora pathosystem: resistance requires a functional PAD2 gene and is independent of salicylic acid, ethylene and jasmonic acid signalling.

    PubMed

    Roetschi, A; Si-Ammour, A; Belbahri, L; Mauch, F; Mauch-Mani, B

    2001-11-01

    Arabidopsis accessions were screened with isolates of Phytophthora porri originally isolated from other crucifer species. The described Arabidopsis-Phytophthora pathosystem shows the characteristics of a facultative biotrophic interaction similar to that seen in agronomically important diseases caused by Phytophthora species. In susceptible accessions, extensive colonization of the host tissue occurred and sexual and asexual spores were formed. In incompatible combinations, the plants reacted with a hypersensitive response (HR) and the formation of papillae at the sites of attempted penetration. Defence pathway mutants such as jar1 (jasmonic acid-insensitive), etr1 (ethylene receptor mutant) and ein2 (ethylene-insensitive) remained resistant towards P. porri. However, pad2, a mutant with reduced production of the phytoalexin camalexin, was hyper-susceptible. The accumulation of salicylic acid (SA) and PR1 protein was strongly reduced in pad2. Surprisingly, this lack of SA accumulation does not appear to be the cause of the hyper-susceptibility because interference with SA signalling in nahG plants or sid2 or npr1 mutants had only a minor effect on resistance. In addition, the functional SA analogue benzothiadiazol (BTH) did not induce resistance in susceptible plants including pad2. Similarly, the complete blockage of camalexin biosynthesis in pad3 did not cause susceptibility. Resistance of Arabidopsis against P. porri appears to depend on unknown defence mechanisms that are under the control of PAD2.

  9. Organic acids on the growth, anatomical structure, biochemical parameters and heavy metal accumulation of Iris lactea var. chinensis seedling growing in Pb mine tailings.

    PubMed

    Han, Yu-Lin; Huang, Su-Zhen; Yuan, Hai-Yan; Zhao, Jiu-Zhou; Gu, Ji-Guang

    2013-08-01

    The effect of citric acid (CA) and ethylene diamine tetraacetic acid (EDTA) on the growth, anatomical structure, physiological responses and lead (Pb) accumulation of Iris lactea var. chinensis seedling growing in Pb mine tailings for 30 days were studied. Results showed that the dry weights (DW) of roots decreased significantly under both levels of CA. The DWs of leaves and roots treated with 2 mmol/kg EDTA decreased significantly and were 23 and 54 %, respectively, lower than those of the control. The tolerant indexes of I. lactea var. chinensis under all treatments of organic acids were lower than control. The root tip anatomical structure was little affected under the treatments of 2 mmol/kg CA and 2 mmol/kg EDTA compared with control. However, the formation of photosynthesizing cells was inhibited by the treatment of 2 mmol/kg EDTA. The concentrations of chlorophyll a, chlorophyll b and total carotenoids in the leaves treated with 2 mmol/kg EDTA significantly decreased. Higher CA level and lower EDTA level could trigger the synthesis of ascorbic acid and higher level of EDTA could trigger the synthesis of glutathione. CA and EDTA could promote Pb accumulation of I. lactea var. chinensis and Pb concentration in the leaves and roots at 2 mmol/kg EDTA treatment increased significantly and reached to 160.44 and 936.08 μg/g DW, respectively, and 1.8 and 1.6 times higher than those of the control. The results indicated that I. lactea var. chinensis could be used to remediate Pb tailing and the role of EDTA in promoting Pb accumulation was better than CA did.

  10. A Laser-Pointer-Based Spectrometer for Endpoint Detection of EDTA Titrations

    ERIC Educational Resources Information Center

    Dahm, Christopher E.; Hall, James W.; Mattioni, Brian E.

    2004-01-01

    A laser spectrometer for the ethylenediaminetetra-acetic acid (EDTA) titration of magnesium or calcium ions that is designed around a handheld laser pointer as the source and a photoresistor as the detector is developed. Findings show that the use of the spectrometer reduces the degree of uncertainty and error in one part of the EDTA titrations,…

  11. Synthesis, structure, and properties of Cu doped Bi 4V IIO 11 via EDTA-citrate gel process

    NASA Astrophysics Data System (ADS)

    Guo, Ming; Deng, Hongmei; Yang, Pingxiong

    2008-02-01

    The oxide ion conductor material, Cu doped Bi 4V IIO 11 (BICUVOX.10) powders were prepared by the combined EDTA (ethylene diamine tetra acetic acid)-citrate synthesis technology. The dried gel was annealed at various temperatures (400-600°C). Powders derived from dried precursor resulted in the mixed phases to BiVO 4 and high temperature γ-phase of Bi 4V IIO 11 by heat-treating below 400°C, and furthermore, yielded only pure γ-phase above 500°C. A simple surfactant-stabilized method was investigated for the preparation of well-dispersed nanoparticles. It was found that the deagglomeration treatment to the precursor by surfactant polyethylene glycol (PEG) 4000 was effective in improving the size distribution and annealing conditions of the BICUVOX.10 material.

  12. Bacteria-triggered systemic immunity in barley is associated with WRKY and ETHYLENE RESPONSIVE FACTORs but not with salicylic acid.

    PubMed

    Dey, Sanjukta; Wenig, Marion; Langen, Gregor; Sharma, Sapna; Kugler, Karl G; Knappe, Claudia; Hause, Bettina; Bichlmeier, Marlies; Babaeizad, Valiollah; Imani, Jafargholi; Janzik, Ingar; Stempfl, Thomas; Hückelhoven, Ralph; Kogel, Karl-Heinz; Mayer, Klaus F X; Vlot, A Corina

    2014-12-01

    Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity.

  13. Self-assembled poly(ethylene glycol)-co-acrylic acid microgels to inhibit bacterial colonization of synthetic surfaces.

    PubMed

    Wang, Qichen; Uzunoglu, Emel; Wu, Yong; Libera, Matthew

    2012-05-01

    We explored the use of self-assembled microgels to inhibit the bacterial colonization of synthetic surfaces both by modulating surface cell adhesiveness at length scales comparable to bacterial dimensions (∼1 μm) and by locally storing/releasing an antimicrobial. Poly(ethylene glycol) [PEG] and poly(ethylene glycol)-co-acrylic acid [PEG-AA] microgels were synthesized by suspension photopolymerization. Consistent with macroscopic gels, a pH dependence of both zeta potential and hydrodynamic diameter was observed in AA-containing microgels but not in pure PEG microgels. The microgels were electrostatically deposited onto poly(l-lysine) (PLL) primed silicon to form submonolayer surface coatings. The microgel surface density could be controlled via the deposition time and the microgel concentration in the parent suspension. In addition to their intrinsic antifouling properties, after deposition, the microgels could be loaded with a cationic antimicrobial peptide (L5) because of favorable electrostatic interactions. Loading was significantly higher in PEG-AA microgels than in pure PEG microgels. The modification of PLL-primed Si by unloaded PEG-AA microgels reduced the short-term (6 h) S. epidermidis surface colonization by a factor of 2, and the degree of inhibition increased when the average spacing between microgels was reduced. Postdeposition L5 peptide loading into microgels further reduced bacterial colonization to the extent that, after 10 h of S. epidermidis culture in tryptic soy broth, the colonization of L5-loaded PEG-AA microgel-modified Si was comparable to the very small level of colonization observed on macroscopic PEG gel controls. The fact that these microgels can be deposited by a nonline-of-sight self-assembly process and hinder bacterial colonization opens the possibility of modifying the surfaces of topographically complex biomedical devices and reduces the rate of biomaterial-associated infection.

  14. Differential responses of certain lichen species to sulfur-containing solutions under acidic conditions as expressed by the production of stress-ethylene

    SciTech Connect

    Garty, J.; Kauppi, M.; Kauppi, A.

    1995-05-01

    To determine whether fluctuations in the concentration of ethylene produced by lichens exposed to sulfur-containing solutions at a low pH correlate with the tolerance/sensitivity of these lichens to air pollution, we measured the amount of ethylene produced by thalli soaked in H{sub 2}SO{sub 4} and NaHSO{sub 3}. The exposure of Hypogymnia physodes, Cladina stellaris, and Bryoria fuscescens to H{sub 2}SO{sub 4} at a pH ranging between 4.0 and 2.0 did not produce changes in the concentration of ethylene in comparison with samples wetted with H{sub 2}O at pH 6.8. The exposure of two pendulous lichens, Usnea hirta and Alectoria sarmentosa, to 1.0 and 5.0 mM H{sub 2}SO{sub 4} at pH 2.7 and 2.0, respectively, stimulated only a slight increase of ethylene production, whereas another pendulous lichen, Bryoria fremontii, exposed to H{sub 2}SO{sub 4} at pH 4.0-2.0 decreased its production of ethylene. The soaking of H. physodes, U. hirta, C. stellaris, and A. sarmentosa thalli in NaHSO{sub 3} at pH 4.0 gradually increased the production of ethylene. The exposure of B. fremontii and B. fuscescens to low NaHSO{sub 3} concentrations depressed the production of ethylene in these lichens. The indifference of H. physodes to H{sub 2}SO{sub 4} under strong acidic conditions correlated with its resistance to SO{sub 21} in the air. In accordance with a model by D.M. Reid (In {open_quotes}Effects of Atmospheric Pollutants on Forests, Wetlands and Agricultural Ecosystems. NATO ASI Series, Springer-Verlag, Berlin and Heidelberg, 1987) referring to higher plants, it is suggested that sulfur-containing solutions under acidic conditions increase the solubility of particles containing heavy metals entrapped among the mycobiont hyphae in lichens. This may lead to an increase of the production of endogenous ethylene in lichens as they are exposed to sulfur-containing chemicals, to acidic rain, or to heavy metal-polluted air. 65 refs., 8 tabs.

  15. Differential responses of certain lichen species to sulfur-containing solutions under acidic conditions as expressed by the production of stress-ethylene.

    PubMed

    Garty, J; Kauppi, M; Kauppi, A

    1995-05-01

    To determine whether fluctuations in the concentration of ethylene produced by lichens exposed to sulfur-containing solutions at a low pH correlate with the tolerance/sensitivity of these lichens to air pollution, we measured the amount of ethylene produced by thalli soaked in H2SO4 and NaHSO3. The exposure of Hypogymnia physodes, Cladina stellaris, and Bryoria fuscescens to H2SO4 at a pH ranging between 4.0 and 2.0 did not produce changes in the concentration of ethylene in comparison with samples wetted with H2O at pH 6.8. The exposure of two pendulous lichens, Usnea hirta and Alectoria sarmentosa, to 1.0 and 5.0 mM H2SO4 at pH 2.7 and 2.0, respectively, stimulated only a slight increase of ethylene production, whereas another pendulous lichen, Bryoria fremontii, exposed to H2SO4 at pH 4.0-2.0 decreased its production of ethylene. The soaking of H. physodes, U. hirta, C. stellaris, and A. sarmentosa thalli in NaHSO3 at pH 4.0 gradually increased the production of ethylene. The exposure of B. fremontii and B. fuscescens to low NaHSO3 concentrations depressed the production of ethylene in these lichens. The indifference of H. physodes to H2SO4 under strong acidic conditions correlated with its resistance to SO2 in the air. In accordance with a model by D.M. Reid (In "Effects of Atmospheric Pollutants on Forests, Wetlands and Agricultural Ecosystems" (T.C. Hutchinson and K.M. Meema, Eds.), Vol G 16, pp. 241-245. NATO ASI Series, Springer-Verlag, Berlin and Heidelberg, 1987) referring to higher plants, it is suggested that sulfur-containing solutions under acidic conditions increase the solubility of particles containing heavy metals entrapped among the mycobiont hyphae in lichens. This may lead to an increase of the production of endogenous ethylene in lichens as they are exposed to sulfur-containing chemicals, to acidic rain, or to heavy metal-polluted air.

  16. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  17. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  18. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  19. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  20. 21 CFR 172.135 - Disodium EDTA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Disodium EDTA. 172.135 Section 172.135 Food and... PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.135 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-tate) may be safely used in...

  1. 21 CFR 573.360 - Disodium EDTA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Disodium EDTA. 573.360 Section 573.360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Listing § 573.360 Disodium EDTA. The food additive disodium EDTA (disodium ethylenediaminetetraace-...

  2. Block and Random Copolymers Bearing Cholic Acid and Oligo(ethylene glycol) Pendant Groups: Aggregation, Thermosensitivity, and Drug Loading

    PubMed Central

    2015-01-01

    A series of block and random copolymers consisting of oligo(ethylene glycol) and cholic acid pendant groups were synthesized via ring-opening metathesis polymerization of their norbornene derivatives. These block and random copolymers were designed to have similar molecular weights and comonomer ratios; both types of copolymers showed thermosensitivity in aqueous solutions with similar cloud points. The copolymers self-assembled into micelles in water as shown by dynamic light scattering and transmission electron microscopy. The hydrodynamic diameter of the micelles formed by the block copolymer is much larger and exhibited a broad and gradual shrinkage from 20 to 54 °C below its cloud point, while the micelles formed by the random copolymers are smaller in size but exhibited some swelling in the same temperature range. Based on in vitro drug release studies, 78% and 24% paclitaxel (PTX) were released in 24 h from micelles self-assembled by the block and random copolymers, respectively. PTX-loaded micelles formed by the block and random copolymers exhibited apparent antitumor efficacy toward the ovarian cancer cells with a particularly low half-maximal inhibitory concentration (IC50) of 27.4 and 40.2 ng/mL, respectively. Cholic acid-based micelles show promise as a versatile and potent platform for cancer chemotherapy. PMID:24725005

  3. Block and random copolymers bearing cholic acid and oligo(ethylene glycol) pendant groups: aggregation, thermosensitivity, and drug loading.

    PubMed

    Shao, Yu; Jia, Yong-Guang; Shi, Changying; Luo, Juntao; Zhu, X X

    2014-05-12

    A series of block and random copolymers consisting of oligo(ethylene glycol) and cholic acid pendant groups were synthesized via ring-opening metathesis polymerization of their norbornene derivatives. These block and random copolymers were designed to have similar molecular weights and comonomer ratios; both types of copolymers showed thermosensitivity in aqueous solutions with similar cloud points. The copolymers self-assembled into micelles in water as shown by dynamic light scattering and transmission electron microscopy. The hydrodynamic diameter of the micelles formed by the block copolymer is much larger and exhibited a broad and gradual shrinkage from 20 to 54 °C below its cloud point, while the micelles formed by the random copolymers are smaller in size but exhibited some swelling in the same temperature range. Based on in vitro drug release studies, 78% and 24% paclitaxel (PTX) were released in 24 h from micelles self-assembled by the block and random copolymers, respectively. PTX-loaded micelles formed by the block and random copolymers exhibited apparent antitumor efficacy toward the ovarian cancer cells with a particularly low half-maximal inhibitory concentration (IC50) of 27.4 and 40.2 ng/mL, respectively. Cholic acid-based micelles show promise as a versatile and potent platform for cancer chemotherapy. PMID:24725005

  4. Expression of genes associated with the biosynthetic pathways of abscisic acid, gibberellin, and ethylene during the germination of lettuce seeds.

    PubMed

    Clemente, A C S; Guimarães, R M; Martins, D C; Gomes, L A A; Caixeta, F; Reis, R G E; Rosa, S D V F

    2015-05-11

    Seed germination and dormancy are complex phenomena that are controlled by many genes and environmental factors. Such genes are indicated by phytohormones that interact with each other, and may cause dormancy or promote seed germination. The objective of this study was to investigate gene expression associated with the biosynthetic pathways of abscisic acid (ABA), gibberellic acid (GA), and ethylene (ET) in dormant and germinated lettuce seeds. The expressions of LsNCED, LsGA3ox1, and ACO-B were evaluated in germinating and dormant seeds from the cultivars Everglades, Babá de Verão, Verônica, Salinas, Colorado, and Regina 71. The expressions of LsNCED, LsGA3ox1, and ACO-B were related to the biosynthesis of ABA, GA, and ET, respectively; therefore, the presence of these substances depends on genotype. LsNCED expression only occurred in dormant seeds, and was connected to dormancy. LsGA3ox1expression only occurred in germinated seeds, and was connected to germination. The ACO-B gene was involved in ET biosynthesis, and was expressed differently in germinated and dormant seeds, depending on the genotype, indicating different functions for different characteristics. Furthermore, sensitivity to phytohormones appeared to be more important than the expression levels of LsNCED, LsGA3ox1, or ACO-B.

  5. Expression of genes associated with the biosynthetic pathways of abscisic acid, gibberellin, and ethylene during the germination of lettuce seeds.

    PubMed

    Clemente, A C S; Guimarães, R M; Martins, D C; Gomes, L A A; Caixeta, F; Reis, R G E; Rosa, S D V F

    2015-01-01

    Seed germination and dormancy are complex phenomena that are controlled by many genes and environmental factors. Such genes are indicated by phytohormones that interact with each other, and may cause dormancy or promote seed germination. The objective of this study was to investigate gene expression associated with the biosynthetic pathways of abscisic acid (ABA), gibberellic acid (GA), and ethylene (ET) in dormant and germinated lettuce seeds. The expressions of LsNCED, LsGA3ox1, and ACO-B were evaluated in germinating and dormant seeds from the cultivars Everglades, Babá de Verão, Verônica, Salinas, Colorado, and Regina 71. The expressions of LsNCED, LsGA3ox1, and ACO-B were related to the biosynthesis of ABA, GA, and ET, respectively; therefore, the presence of these substances depends on genotype. LsNCED expression only occurred in dormant seeds, and was connected to dormancy. LsGA3ox1expression only occurred in germinated seeds, and was connected to germination. The ACO-B gene was involved in ET biosynthesis, and was expressed differently in germinated and dormant seeds, depending on the genotype, indicating different functions for different characteristics. Furthermore, sensitivity to phytohormones appeared to be more important than the expression levels of LsNCED, LsGA3ox1, or ACO-B. PMID:25966245

  6. Structure and DNA Hybridization Properties of Mixed Nucleic Acid/Maleimide-Ethylene Glycol Monolayers

    SciTech Connect

    Lee,C.; Nguyen, P.; Grainger, D.; Gamble, L.; Castner, D.

    2007-01-01

    The surface structure and DNA hybridization performance of thiolated single-strand DNA (HS-ssDNA) covalently attached to a maleimide-ethylene glycol disulfide (MEG) monolayer on gold have been investigated. Monolayer immobilization chemistry and surface coverage of reactive ssDNA probes were studied by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. Orientation of the ssDNA probes was determined by near-edge X-ray absorption fine structure (NEXAFS). Target DNA hybridization on the DNA-MEG probe surfaces was measured by surface plasmon resonance (SPR) to demonstrate the utility of these probe surfaces for detection of DNA targets from both purified target DNA samples and complex biological mixtures such as blood serum. Data from complementary techniques showed that immobilized ssDNA density is strongly dependent on the spotted bulk DNA concentration and buffer ionic strength. Variation of the immobilized ssDNA density had a profound influence on the DNA probe orientation at the surface and subsequent target hybridization efficiency. With increasing surface probe density, NEXAFS polarization dependence results (followed by monitoring the N 1s {yields} {pi}* transition) indicate that the immobilized ssDNA molecules reorient toward a more upright position on the MEG monolayer. SPR assays of DNA targets from buffer and serum showed that DNA hybridization efficiency increased with decreasing surface probe density. However, target detection in serum was better on the 'high-density' probe surface than on the 'high-efficiency' probe surface. The amounts of target detected for both ssDNA surfaces were several orders of magnitude poorer in serum than in purified DNA samples due to nonspecific serum protein adsorption onto the sensing surface.

  7. DEVELOPMENT OF A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR ETHYLENE GLYCOL AND ITS MAJOR METABOLITE, GLYCOLIC ACID, IN RATS AND HUMANS

    SciTech Connect

    Corley, Rick A.; Bartels, M J.; Carney, E W.; Weitz, Karl K.; Soelberg, Jolen J.; Gies, Richard A.; Thrall, Karla D.

    2005-05-19

    An extensive database on the toxicity and modes of action of the major industrial chemical, ethylene glycol (EG), has been developed over the past several decades. These studies have consistently identified the kidney as a primary target organ, with rats being more sensitive than mice and males more sensitive than females following chronic exposure. Renal toxicity has been associated with the terminal metabolite, oxalic acid which can precipitate with calcium to form crystals. EG also induces developmental toxicity, although these effects appear to require high-doses or accelerated dose-rates, and have been reported only in rats and mice. The developmental toxicity of EG has been attributed to the intermediate metabolite, glycolic acid (GA). The developmental toxicity of EG has been the subject of extensive research and regulatory review in recent years. Therefore, a physiologically based pharmacokinetic (PBPK) model was developed to integrate the extensive mode of action and pharmacokinetic data on EG and GA for use in developmental risk assessment. Metabolic rate constants and partition coefficients for EG and GA were estimated from in vitro studies. Other biochemical constants were optimized from appropriate in vivo pharmacokinetic studies. The resulting PBPK model includes inhalation, oral, dermal, intravenous and subcutaneous routes of administration. Metabolism of EG and GA were described in the liver with elimination via the kidneys. Several rat and human metabolism studies were used to validate the resulting PBPK model. Consistent with these studies, simulations indicated that the metabolism of EG to GA was essentially first-order (linear) up to 2500 mg/kg/day while the metabolism of GA saturated between bolus ethylene glycol doses of 200 and 1000 mg/kg/day. This saturation results in non-linear increases in blood GA concentrations, correlating with the developmental toxicity of EG. Pregnancy had no effect on maternal EG and GA kinetics over a broad dose

  8. Lead-enhanced gas-phase stability of multiply charged EDTA anions: a combined experimental and theoretical study.

    PubMed

    Liu, Chunxiao; Ouyang, Yongzhong; Jia, Bin; Zhu, Zhiqiang; Shi, Jianbo; Chen, Huanwen

    2012-06-01

    Besides their fundamental importance, multiply charged anions (MCAs) are considered as promising molecular capacitors for which their intrinsic stabilities are of great significance. Herein, the gas-phase stabilities of ethylenediaminetetraacetic acid (EDTA) anions (i.e. [EDTA-nH](n-), n = 1-4) and their Pb(II) complexes (i.e. [EDTA + Pb-nH]((2-n)-), n = 3, 4) have been investigated using an approach that combines extractive electrospray ionization mass spectrometry (EESI-MS) measurements, Car-Parrinello molecular dynamics simulations and density functional theory/Tao-Perdew-Staroverov-Scuseria calculations. The EESI-MS data showed that the doubly charged EDTA anions in the form of [EDTA-2H](2-) and [EDTA + Pb-4H](2-) were much more abundantly observed than the singly charged species such as [EDTA-H](-) and [EDTA + Pb-3H](-), respectively. The calculation results indicated that [EDTA-2H](2-) and [EDTA + Pb-4H](2-) anions were thermodynamically more stable than the [EDTA-H](-) and [EDTA + Pb-3H](-) species in the gas phase, respectively. The [EDTA + Pb-3H](-) anions preferred five-coordinated structure, whereas [EDTA + Pb-4H](2-) anions formed either five-coordinated or six-coordinated structures. The calculations further revealed that significant electron clouds drifting from the ligand EDTA to the metal Pb(II) ions and the large distances between the carboxylic groups reduced the Coulomb repulsion among the excess electrons of these MCAs. Our data demonstrated that EESI-MS combined with theoretic calculations were able to provide a deep insight into the fundamental behavior of stability of MCAs in the gas phase and, thus, might be useful tools for studying MCAs for potential molecular capacitors.

  9. Synergistic antibiofilm efficacy of various commercial antiseptics, enzymes and EDTA: a study of Pseudomonas aeruginosa and Staphylococcus aureus biofilms.

    PubMed

    Lefebvre, Elodie; Vighetto, Christophe; Di Martino, Patrick; Larreta Garde, Véronique; Seyer, Damien

    2016-08-01

    A multistep strategy was used to generate a combined antibiofilm treatment that could efficiently decrease the biomass of dense biofilms (≥6 × 10(7) CFU/cm(2)). Several compounds that exhibited activity against various targets were tested individually and in combination to search for possible synergistic effects. First, the antibiofilm activity of various commercially available antiseptics was tested on Pseudomonas aeruginosa and Staphylococcus aureus. Second, antiseptics were mixed with ethylene diamine tetra-acetic acid (EDTA), which is an ion chelator that can disturb biofilm organisation, and additive effects on biofilm biomass degradation were found for both strains. Then, enzymes with the ability to destabilise the biofilm matrix by hydrolysing either its proteins or its polysaccharides were used; as expected, they did not decrease bacterial viability but were revealed as efficient biomass reducers. The combination of antiseptics, EDTA and proteases, all at low concentrations, revealed a synergistic effect leading to total eradication of dense biofilms both of P. aeruginosa and S. aureus. PMID:27424598

  10. TGA Transcription Factors Activate the Salicylic Acid-Suppressible Branch of the Ethylene-Induced Defense Program by Regulating ORA59 Expression.

    PubMed

    Zander, Mark; Thurow, Corinna; Gatz, Christiane

    2014-07-01

    Salicylic acid (SA), a hormone essential for defense against biotrophic pathogens, triggers increased susceptibility of plants against necrotrophic attackers by suppressing the jasmonic acid-ethylene (ET) defense response. Here, we show that this disease-promoting SA effect is abolished in plants lacking the three related TGACG sequence-specific binding proteins TGA2, TGA5, and TGA6 (class II TGAs). After treatment of plants with the ET precursor 1-aminocyclopropane-1-carboxylic acid (ACC), activation of all those genes that are suppressed by SA depended on class II TGAs. Rather than TGA binding sites, GCC-box motifs were significantly enriched in the corresponding promoters. GCC-box motifs are recognized by members of the superfamily of APETALA2/ETHYLENE RESPONSE FACTORs (ERFs). Of 11 activating ACC-induced APETALA2/ERFs, only ORA59 (for OCTADECANOID-RESPONSIVE ARABIDOPSIS APETALA2/ETHYLENE RESPONSE FACTOR domain protein59) and ERF96 were strongly suppressed by SA. ORA59 is the master regulator of the jasmonic acid-ET-induced defense program. ORA59 transcript levels do not reach maximal levels in the tga2 tga5 tga6 triple mutant, and this residual activity cannot be suppressed by SA. The ORA59 promoter contains an essential TGA binding site and is a direct target of class II TGAs as revealed by chromatin immunoprecipitation experiments. We suggest that class II TGAs at the ORA59 promoter constitute an important regulatory hub for the activation and SA suppression of ACC-induced genes.

  11. TGA Transcription Factors Activate the Salicylic Acid-Suppressible Branch of the Ethylene-Induced Defense Program by Regulating ORA59 Expression1[C][W

    PubMed Central

    Zander, Mark; Thurow, Corinna; Gatz, Christiane

    2014-01-01

    Salicylic acid (SA), a hormone essential for defense against biotrophic pathogens, triggers increased susceptibility of plants against necrotrophic attackers by suppressing the jasmonic acid-ethylene (ET) defense response. Here, we show that this disease-promoting SA effect is abolished in plants lacking the three related TGACG sequence-specific binding proteins TGA2, TGA5, and TGA6 (class II TGAs). After treatment of plants with the ET precursor 1-aminocyclopropane-1-carboxylic acid (ACC), activation of all those genes that are suppressed by SA depended on class II TGAs. Rather than TGA binding sites, GCC-box motifs were significantly enriched in the corresponding promoters. GCC-box motifs are recognized by members of the superfamily of APETALA2/ETHYLENE RESPONSE FACTORs (ERFs). Of 11 activating ACC-induced APETALA2/ERFs, only ORA59 (for OCTADECANOID-RESPONSIVE ARABIDOPSIS APETALA2/ETHYLENE RESPONSE FACTOR domain protein59) and ERF96 were strongly suppressed by SA. ORA59 is the master regulator of the jasmonic acid-ET-induced defense program. ORA59 transcript levels do not reach maximal levels in the tga2 tga5 tga6 triple mutant, and this residual activity cannot be suppressed by SA. The ORA59 promoter contains an essential TGA binding site and is a direct target of class II TGAs as revealed by chromatin immunoprecipitation experiments. We suggest that class II TGAs at the ORA59 promoter constitute an important regulatory hub for the activation and SA suppression of ACC-induced genes. PMID:24989234

  12. Evaluation of Physical and Mechanical Properties of Porous Poly (Ethylene Glycol)-co-(L-Lactic Acid) Hydrogels during Degradation

    PubMed Central

    Chiu, Yu-Chieh; Kocagöz, Sevi; Larson, Jeffery C.; Brey, Eric M.

    2013-01-01

    Porous hydrogels of poly(ethylene glycol) (PEG) have been shown to facilitate vascularized tissue formation. However, PEG hydrogels exhibit limited degradation under physiological conditions which hinders their ultimate applicability for tissue engineering therapies. Introduction of poly(L-lactic acid) (PLLA) chains into the PEG backbone results in copolymers that exhibit degradation via hydrolysis that can be controlled, in part, by the copolymer conditions. In this study, porous, PEG-PLLA hydrogels were generated by solvent casting/particulate leaching and photopolymerization. The influence of polymer conditions on hydrogel architecture, degradation and mechanical properties was investigated. Autofluorescence exhibited by the hydrogels allowed for three-dimensional, non-destructive monitoring of hydrogel structure under fully swelled conditions. The initial pore size depended on particulate size but not polymer concentration, while degradation time was dependent on polymer concentration. Compressive modulus was a function of polymer concentration and decreased as the hydrogels degraded. Interestingly, pore size did not vary during degradation contrary to what has been observed in other polymer systems. These results provide a technique for generating porous, degradable PEG-PLLA hydrogels and insight into how the degradation, structure, and mechanical properties depend on synthesis conditions. PMID:23593296

  13. Biocompatibility of poly(ethylene glycol) and poly(acrylic acid) interpenetrating network hydrogel by intrastromal implantation in rabbit cornea

    PubMed Central

    Zheng, Luo Luo; Vanchinathan, Vijay; Dalal, Roopa; Noolandi, Jaan; Waters, Dale J.; Hartmann, Laura; Cochran, Jennifer R.; Frank, Curtis W.; Yu, Charles Q.; Ta, Christopher N.

    2015-01-01

    We evaluated the biocompatibility of a poly(ethylene glycol) and poly(acrylic acid) (PEG/PAA) interpenetrating network hydrogel designed for artificial cornea in a rabbit model. PEG/PAA hydrogel measuring 6 mm in diameter was implanted in the corneal stroma of twelve rabbits. Stromal flaps were created with a microkeratome. Randomly, six rabbits were assigned to bear the implant for 2 months, two rabbits for 6 months, two rabbits for 9 months, one rabbit for 12 months, and one rabbit for 16 months. Rabbits were evaluated monthly. After the assigned period, eyes were enucleated, and corneas were processed for histology and immunohistochemistry. There were clear corneas in three of six rabbits that had implantation of hydrogel for 2 months. In the six rabbits with implant for 6 months or longer, the corneas remained clear in four. There was a high rate of epithelial defect and corneal thinning in these six rabbits. One planned 9-month rabbit developed extrusion of implant at 4 months. The cornea remained clear in the 16-month rabbit but histology revealed epithelial in-growth. Intrastromal implantation of PEG/PAA resulted in a high rate of long-term complications. PMID:25778285

  14. Poly(ethylene oxide)-block-poly(glutamic acid) coated maghemite nanoparticles: in vitro characterization and in vivo behaviour

    NASA Astrophysics Data System (ADS)

    Kaufner, L.; Cartier, R.; Wüstneck, R.; Fichtner, I.; Pietschmann, S.; Bruhn, H.; Schütt, D.; Thünemann, A. F.; Pison, U.

    2007-03-01

    Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aqueous solution and subsequently stabilized with poly(ethylene oxide)-block-poly(glutamic acid) (PEO-PGA) at a hydrodynamic diameter of 60 nm. Depending on the amount of PEO-PGA used, this is accompanied by a switching of their zeta potentials from positive to negative charge (-33 mV). As a prerequisite for in vivo testing, the PEO-PGA coated maghemite nanoparticles were evaluated to be colloidally stable in water and in physiological salt solution for longer than six months as well in various buffer systems under physiological pH and salt conditions (AFM, dynamic light scattering). We excluded toxic effects of the PEO-PGA coated maghemite nanoparticles. We demonstrated by in vivo MR-imaging and 111In measurements a biodistribution of the nanoparticles into the liver comparable to carboxydextran coated superparamagnetic iron oxide nanoparticles (Resovist®) as a reference nanoscaled MRI contrast medium. This was enforced by a detailed visualization of our nanoparticles by electron microscopy of liver tissue sections. Furthermore, our results indicate that 15% of the injected PEO-PGA coated maghemite nanoparticles circulate in the blood compartment for at least 60 min after i.v. application.

  15. Synthesis of silica coated zinc oxide–poly(ethylene-co-acrylic acid) matrix and its UV shielding evaluation

    SciTech Connect

    Ramasamy, Mohankandhasamy; Kim, Yu Jun; Gao, Haiyan; Yi, Dong Kee; An, Jeong Ho

    2014-03-01

    Graphical abstract: - Highlights: • Well layer thickness controlled silica shell was made on ZnO nanoparticles. • PEAA, an interfacial agent is used to make nanocomposite–polymer matrix by twin-screw extruder. • Si-ZnO/PEAA matrix is highly stable and UV protective as compared to ZnO/PEAA matrix. • Nanoparticle embedded polymer matrix is suggested to make UV shielding fabrics with Nylon4. - Abstract: Silica coated zinc oxide nanoparticles (Si-ZnO NPs) (7 nm thick) were synthesized successfully and melt blended with poly(ethylene-co-acrylic acid) (PEAA resin) to improving ultraviolet (UV) shielding of zinc oxide nanoparticles (ZnO NPs). The photostability of both the ZnO NPs and Si-ZnO NPs were analyzed by the difference in photoluminescence (PL) and by methylene blue (MB) degradation. Photo-degradation studies confirmed that Si-ZnO NPs are highly photostable compared to ZnO NPs. The melt blended matrices were characterized by field emission scanning electron microscopy interfaced with energy dispersive X-ray spectroscopy (FE-SEM-EDX). The UV shielding property was analyzed from the transmittance spectra of UV–visible (UV–vis) spectroscopy. The results confirmed fine dispersion of thick Si-ZnO NPs in the entire resin matrix. Moreover, the Si-ZnO/PEAA showed about 97% UV shielding properties than the ZnO/PEAA.

  16. Wavelength Shifters and Interactions of EDTA with Acrylic & LAB

    NASA Astrophysics Data System (ADS)

    Mohan, Yuvraj; SNO+ Collaboration

    2014-09-01

    The SNO + experiment, an upgrade to the Sudbury Neutrino Observatory, will use linear alkyl-benzene (LAB) liquid scintillator to probe new physics, including 0 νββ decay. Event detection efficiency is heavily affected by radioactive backgrounds, two sources being Rn-222 and Po-210 daughters, some of which has become embedded in the SNO + acrylic vessel after years underground. The leading candidate for polonium leaching is Ethylenediaminetetraacetic acid (EDTA). Before deployment on-site, EDTA's effects on the mechanical integrity of acrylic must be determined. It also must not be soluble in LAB or must be removed before scintillator fill of the vessel, as its presence would result in reduced light yield due to scattering. It was found that EDTA had negligible effects on the Young's Modulus of acrylic. EDTA is also slightly soluble in LAB, but can be completely removed by rinsing with water. Additionally, the study of the light yield and alpha/beta timing profiles of two wavelength shifters - bisMSB and perylene - is critical to determining which should be added to the 0 νββ isotope (tellurium) LAB cocktail. Small-scale results hint that perylene might be better, but this is being confirmed with larger-scale tests. The SNO + experiment, an upgrade to the Sudbury Neutrino Observatory, will use linear alkyl-benzene (LAB) liquid scintillator to probe new physics, including 0 νββ decay. Event detection efficiency is heavily affected by radioactive backgrounds, two sources being Rn-222 and Po-210 daughters, some of which has become embedded in the SNO + acrylic vessel after years underground. The leading candidate for polonium leaching is Ethylenediaminetetraacetic acid (EDTA). Before deployment on-site, EDTA's effects on the mechanical integrity of acrylic must be determined. It also must not be soluble in LAB or must be removed before scintillator fill of the vessel, as its presence would result in reduced light yield due to scattering. It was found that EDTA

  17. Reactive Poly(Amic Acid)/ Poly(Glycidyl Methacrylate-r-Poly(ethylene Glycol) Methyl Ether Methacrylate) Blends as Gas Permeation Membranes

    NASA Astrophysics Data System (ADS)

    Beaulieu, Michael; Watkins, James

    2012-02-01

    Polymers containing polar moieties, such as ether groups show an affinity for acidic gases, such as CO2 due to dipole-quadrapole interactions. Polymer blends in which one of the components is poly(ethylene glycol) (PEG) have been studied extensively in literature as a CO2/light gas permeation membrane, but due to the crystallization and poor mechanical properties have been difficult to incorporate PEG above 60wt%. In this study, a series of random copolymers containing both glycidyl methacrylate and poly(ethylene glycol) methyl ether methacrylate in different ratios are blended with a poly(amic acid) prepolymer made from 4, 4'-oxydianiline and pyromellitic dianhydride to create gas permeation membranes. By using a reactive blend PEG loadings above 70% have been realized with sufficient mechanical properties, and since the side chain on the PEGMA is short these blends do not suffer from crystallization.

  18. Glycyrrhetinic acid-poly(ethylene glycol)-glycyrrhetinic acid tri-block conjugates based self-assembled micelles for hepatic targeted delivery of poorly water soluble drug.

    PubMed

    Wu, Fengbo; Xu, Ting; Liu, Chi; Chen, Can; Song, Xiangrong; Zheng, Yu; He, Gu

    2013-01-01

    The triblock 18β-glycyrrhetinic acid-poly(ethylene glycol)18β-glycyrrhetinic acid conjugates (GA-PEG-GA) based self-assembled micelles were synthesized and characterized by FTIR, NMR, transmission electron microscopy, and particle size analysis. The GA-PEG-GA conjugates having the critical micelle concentration of 6 × 10(-5) M were used to form nanosized micelles, with mean diameters of 159.21 ± 2.2 nm, and then paclitaxel (PTX) was incorporated into GA-PEG-GA micelles by self-assembly method. The physicochemical properties of the PTX loaded GA-PEG-GA micelles were evaluated including in vitro cellular uptake, cytotoxicity, drug release profile, and in vivo tissue distribution. The results demonstrate that the GA-PEG-GA micelles had low cytotoxicity and good ability of selectively delivering drug to hepatic cells in vitro and in vivo by the targeting moiety glycyrrhetinic acid. In conclusion, the GA-PEG-GA conjugates have potential medical applications for targeted delivery of poor soluble drug delivery.

  19. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    SciTech Connect

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. In this article, we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed that water

  20. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    DOE PAGES

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. In this article, we provide evidence that ERF96 ismore » a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed

  1. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    PubMed Central

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-01-01

    Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed that water loss in ERF

  2. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    DOE PAGES

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    We report that ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96more » is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed

  3. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis

    SciTech Connect

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-11-26

    We report that ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed that

  4. The Small Ethylene Response Factor ERF96 is Involved in the Regulation of the Abscisic Acid Response in Arabidopsis.

    PubMed

    Wang, Xiaoping; Liu, Shanda; Tian, Hainan; Wang, Shucai; Chen, Jin-Gui

    2015-01-01

    Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene response factors (ERFs) are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2)/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA) responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97, and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96's transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS, and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed that water loss in ERF96

  5. Preparation and Properties of Ethylene Vinyl Acetate Copolymer/Silica Nanocomposites in Presence of EVA-g-Acrylic Acid.

    PubMed

    Tham, Do Quang; Tuan, Vu Manh; Thanh, Dinh Thi Mai; Chinh, Nguyen Thuy; Giang, Nguyen Vu; Trang, Nguyen Thi Thu; Hang, To Thi Xuan; Huong, Ho Thu; Dung, Nguyen Thi Kim; Hoang, Thai

    2015-04-01

    Here we report a facile approach to enhance the dispersibility of ethylene vinyl acetate copolymer (EVA)/silica nanocomposites (for the EVA/silica nanocomposites and interaction between silica nanoparticles (nanosilica) and EVA by adding EVA-g-acrylic acid (EVAgAA) as a compatibilizer, which was formed by grafting acrylic acid onto EVA chains with the aid of dicumyl peroxide). The above nanocomposites with and without EVAgAA were prepared by melt mixing in a Haake intermixer with different contents of silica and EVAgAA. Their structure and morphology were characterized by Fourier transform infra-red (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), and the mechanical, rheological, dielectrical, and flammability properties of the nanocomposites were also investigated. The FT-IR spectra of the nanocomposites confirmed the formation of hydrogen bonds between the surface silanol groups of nanosilica and C=O groups of EVA and/or EVAgAA. The presence of EVAgAA remarkably increased the intensity of hydrogen bonding between nanosilica and EVA which not only enhanced the dispersion of nanosilica in EVA matrix but also increased the mechanical, viscosity and storage modulus of EVA/silica nanocomposites. In addition, the flammability of EVA/silica nanocomposites is also significantly reduced after the functionalization with EVAgAA. However, the mechanical properties of EVA/silica nanocomposites tended to level off when its content was above 1.5 wt.%. It has also been found that the dielectric constant value of the EVA/EVAgAA/silica nanocomposites is much lower than that of the EVA/silica nanocomposites, which is another evidence of the hydrogen bonding formation between EVAgAA and nanosilica. PMID:26353492

  6. Complex Formation Between Lysozyme and Stabilized Micelles with a Mixed Poly(ethylene oxide)/Poly(acrylic acid) Shell.

    PubMed

    Karayianni, Maria; Gancheva, Valeria; Pispas, Stergios; Petrov, Petar

    2016-03-10

    The electrostatic complexation between lysozyme and stabilized polymeric micelles (SPMs) with a poly(acrylic acid) (PAA) or a mixed poly(ethylene oxide)/poly(acrylic acid) (PEO/PAA) shell (SPMs with a mixed shell, SPMMS) and a temperature-responsive poly(propylene oxide) (PPO) core was investigated by means of dynamic, static, and electrophoretic light scattering. The SPMs and different types of SPMMS used resulted from the self-assembly of PAA-PPO-PAA triblock copolymer chains, or PAA-PPO-PAA and PEO-PPO-PEO triblock copolymer chain mixtures (with varying chain lengths and molar ratios) in aqueous solutions at pH 10 and the subsequent cross-linking of their PPO cores via loading and photo-cross-linking of pentaerythritol tetraacrylate (PETA). The solution behavior, structure and properties of the formed complexes at pH 7 and 0.01 M ionic strength, were studied as a function of the protein concentration in the solution (the concentration of the stabilized micelles was kept constant) or equivalently the ratio of the two components. The complexation process and properties of the complexes proved to be dependent on the protein concentration, while of particular interest was the effect of the structure of the shell of the SPMs on the stability/solubility of the complexes. Finally, the fluorescence and mid infrared spectroscopic investigation of the structure of the complexed protein showed that, although a small stretching of the protein molecules occurred in some cases, no protein denaturation takes place upon complexation. PMID:26881445

  7. Preparation and Properties of Ethylene Vinyl Acetate Copolymer/Silica Nanocomposites in Presence of EVA-g-Acrylic Acid.

    PubMed

    Tham, Do Quang; Tuan, Vu Manh; Thanh, Dinh Thi Mai; Chinh, Nguyen Thuy; Giang, Nguyen Vu; Trang, Nguyen Thi Thu; Hang, To Thi Xuan; Huong, Ho Thu; Dung, Nguyen Thi Kim; Hoang, Thai

    2015-04-01

    Here we report a facile approach to enhance the dispersibility of ethylene vinyl acetate copolymer (EVA)/silica nanocomposites (for the EVA/silica nanocomposites and interaction between silica nanoparticles (nanosilica) and EVA by adding EVA-g-acrylic acid (EVAgAA) as a compatibilizer, which was formed by grafting acrylic acid onto EVA chains with the aid of dicumyl peroxide). The above nanocomposites with and without EVAgAA were prepared by melt mixing in a Haake intermixer with different contents of silica and EVAgAA. Their structure and morphology were characterized by Fourier transform infra-red (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), and the mechanical, rheological, dielectrical, and flammability properties of the nanocomposites were also investigated. The FT-IR spectra of the nanocomposites confirmed the formation of hydrogen bonds between the surface silanol groups of nanosilica and C=O groups of EVA and/or EVAgAA. The presence of EVAgAA remarkably increased the intensity of hydrogen bonding between nanosilica and EVA which not only enhanced the dispersion of nanosilica in EVA matrix but also increased the mechanical, viscosity and storage modulus of EVA/silica nanocomposites. In addition, the flammability of EVA/silica nanocomposites is also significantly reduced after the functionalization with EVAgAA. However, the mechanical properties of EVA/silica nanocomposites tended to level off when its content was above 1.5 wt.%. It has also been found that the dielectric constant value of the EVA/EVAgAA/silica nanocomposites is much lower than that of the EVA/silica nanocomposites, which is another evidence of the hydrogen bonding formation between EVAgAA and nanosilica.

  8. Ethylene-producing bacteria that ripen fruit.

    PubMed

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples.

  9. EDTA: An Antimicrobial and Antibiofilm Agent for Use in Wound Care

    PubMed Central

    Finnegan, Simon; Percival, Steven L.

    2015-01-01

    Significance: Methods employed for preventing and eliminating biofilms are limited in their efficacy on mature biofilms. Despite this a number of antibiofilm formulations and technologies incorporating ethylenediaminetetraacetic acid (EDTA) have demonstrated efficacy on in vitro biofilms. The aim of this article is to critically review EDTA, in particular tetrasodium EDTA (tEDTA), as a potential antimicrobial and antibiofilm agent, in its own right, for use in skin and wound care. EDTA's synergism with other antimicrobials and surfactants will also be discussed. Recent Advances: The use of EDTA as a potentiating and sensitizing agent is not a new concept. However, currently the application of EDTA, specifically tEDTA as a stand-alone antimicrobial and antibiofilm agent, and its synergistic combination with other antimicrobials to make a “multi-pronged” approach to biofilm control is being explored. Critical Issues: As pathogenic biofilms in the wound increase infection risk, tEDTA could be considered as a potential “stand-alone” antimicrobial/antibiofilm agent or in combination with other antimicrobials, for use in both the prevention and treatment of biofilms found within abiotic (the wound dressing) and biotic (wound bed) environments. The ability of EDTA to chelate and potentiate the cell walls of bacteria and destabilize biofilms by sequestering calcium, magnesium, zinc, and iron makes it a suitable agent for use in the management of biofilms. Future Direction: tEDTA's excellent inherent antimicrobial and antibiofilm activity and proven synergistic and permeating ability results in a very beneficial agent, which could be used for the development of future antibiofilm technologies. PMID:26155384

  10. Poly(lactic acid) / Poly(ethylene glycol) blends: Mechanical, thermal and morphological properties

    NASA Astrophysics Data System (ADS)

    Bijarimi, M.; Ahmad, S.; Rasid, R.; Khushairi, M. A.; Zakir, M.

    2016-04-01

    The poly(lactic acid) (PLA) was melt blended with linear polyethylene glycol (PEG) in an effort to increase the toughness of PLA. Melt blending was carried out in an internal mixer at 180 °C mixing temperature with 50 rpm for 15 minutes. The blends were characterized in terms of mechanical, thermal and morphological properties. It was found that tensile and flexural strength, stiffness and notched Izod impact strength decreased significantly when the PEG was added to the PLA matrix at 2.5-10% of PEG concentrations. Both glass transition and melting temperatures (Tg and Tm) lowered as the concentration of PEG was increased. Moreover, it was noted that the PLA/PEG blends showed a lower onset and peak degradation temperatures but with lower final degradation temperature as compared to the neat PLA. The morphological analysis revealed that the PEG was dispersed as droplets in the PLA matrix with a clear boundary between PLA matrix and PEG phases.

  11. Nanoparticles of Block Ionomer Complexes from Double Hydrophilic Poly(acrylic acid)- b-poly(ethylene oxide)- b-poly(acrylic acid) Triblock Copolymer and Oppositely Charged Surfactant

    NASA Astrophysics Data System (ADS)

    Peng, Zhiping; Sun, Yuelong; Liu, Xinxing; Tong, Zhen

    2010-01-01

    The novel water-dispersible nanoparticles from the double hydrophilic poly(acrylic acid)- b-poly(ethylene oxide)- b-poly(acrylic acid) (PAA- b-PEO- b-PAA) triblock copolymer and oppositely charged surfactant dodecyltrimethyl ammonium bromide (DTAB) were prepared by mixing the individual aqueous solutions. The structure of the nanoparticles was investigated as a function of the degree of neutralization (DN) by turbidimetry, dynamic light scattering (DSL), ζ-potential measurement, and atomic force microscope (AFM). The neutralization of the anionic PAA blocks with cationic DTAB accompanied with the hydrophobic interaction of alkyl tails of DTAB led to formation of core-shell nanoparticles with the core of the DTAB neutralized PAA blocks and the shell of the looped PEO blocks. The water-dispersible nanoparticles with negative ζ-potential were obtained over the DN range from 0.4 to 2.0 and their sizes depended on the DN. The looped PEO blocks hindered the further neutralization of the PAA blocks with cationic DTAB, resulting in existence of some negative charged PAA- b-PEO- b-PAA backbones even when DN > 1.0. The spherical and ellipsoidal nature of these nanoparticles was observed with AFM.

  12. Shape Memory Performance of Thermoplastic Amphiphilic Triblock Copolymer poly(D,L-lactic acid-co-ethylene glycol-co-D,L-lactic acid) (PELA)/Hydroxyapatite Composites

    PubMed Central

    Kutikov, Artem B.; Reyer, Kevin A.

    2015-01-01

    Biodegradable polymer/hydroxyapatite (HA) composites are desired for skeletal tissue engineering. When engineered with thermal-responsive shape memory properties, they may be delivered in a minimally invasive temporary shape and subsequently triggered to conform to a tissue defect. Here we report the shape memory properties of thermoplastic amphiphilic poly(D,L-lactic acid-co-ethylene glycol-co-D,L-lactic acid) (PELA, 120 kDa) and HA-PELA composites. These materials can be cold-deformed and stably fixed into temporary shapes at room temperature and undergo rapid shape recovery (< 3 s) at 50 °C. Stable fixation (>99% fixing ratio) of large deformations is achieved at −20 °C. While the shape recovery from tensile deformations slows with higher HA contents, all composites (up to 20 wt% HA) achieve high shape recovery (>90%) upon 10-min equilibration at 50 °C. The permanent shapes of HA-PELA can be reprogramed at 50 °C, and macroporous shape memory scaffolds can be fabricated by rapid prototyping. PMID:26457046

  13. Factors affecting ethylene and carbon dioxide concentrations during ripening: Incidence on final dry matter, total soluble solids content and acidity of mango fruit.

    PubMed

    Nordey, Thibault; Léchaudel, Mathieu; Génard, Michel; Joas, Jacques

    2016-06-01

    Ripening of climacteric fruits is associated with pronounced changes in fruit gas composition caused by a concomitant rise in respiration and ethylene production. There is a discrepancy in the literature since some authors reported that changes in fruit gas compositions differ in attached and detached fruits. This study presents for the first time an overview of pre- and post-harvest factors that lead to variations in the climacteric respiration and ethylene production, and attempts to determine their impacts on fruit composition, i.e., dry matter, total soluble solids content and acidity. The impact of growing conditions such as the fruit position in the canopy and the fruit carbon supply; fruit detachment from the tree, including the maturity stage at harvest; and storage conditions after harvest, i.e., relative humidity and temperature were considered as well as changes in fruit skin resistance to gas diffusion during fruit growth and storage. Results showed that fruit gas composition vary with all pre and post-harvest factors studied. Although all mangoes underwent a respiratory climacteric and an autocatalytic ethylene production, whatever pre and post-harvest factors studied, large differences in ethylene production, climacteric respiration and fruit quality were measured. Results suggested that the ripening capacity is not related to the fruit ability to produce great amount of ethylene. In agreement with precedent studies, this work provided several lines of evidence that gas composition of fruit is related to its water balance. Our measurements indicated that skin resistance to gas diffusion increased after the harvest and during storage. It was so suggested that the faster ripening of detached fruit may be explained in part by changes in fruit water balance and skin resistance to gas diffusion caused by fruit detachment. PMID:27085177

  14. Factors affecting ethylene and carbon dioxide concentrations during ripening: Incidence on final dry matter, total soluble solids content and acidity of mango fruit.

    PubMed

    Nordey, Thibault; Léchaudel, Mathieu; Génard, Michel; Joas, Jacques

    2016-06-01

    Ripening of climacteric fruits is associated with pronounced changes in fruit gas composition caused by a concomitant rise in respiration and ethylene production. There is a discrepancy in the literature since some authors reported that changes in fruit gas compositions differ in attached and detached fruits. This study presents for the first time an overview of pre- and post-harvest factors that lead to variations in the climacteric respiration and ethylene production, and attempts to determine their impacts on fruit composition, i.e., dry matter, total soluble solids content and acidity. The impact of growing conditions such as the fruit position in the canopy and the fruit carbon supply; fruit detachment from the tree, including the maturity stage at harvest; and storage conditions after harvest, i.e., relative humidity and temperature were considered as well as changes in fruit skin resistance to gas diffusion during fruit growth and storage. Results showed that fruit gas composition vary with all pre and post-harvest factors studied. Although all mangoes underwent a respiratory climacteric and an autocatalytic ethylene production, whatever pre and post-harvest factors studied, large differences in ethylene production, climacteric respiration and fruit quality were measured. Results suggested that the ripening capacity is not related to the fruit ability to produce great amount of ethylene. In agreement with precedent studies, this work provided several lines of evidence that gas composition of fruit is related to its water balance. Our measurements indicated that skin resistance to gas diffusion increased after the harvest and during storage. It was so suggested that the faster ripening of detached fruit may be explained in part by changes in fruit water balance and skin resistance to gas diffusion caused by fruit detachment.

  15. Effects of abscisic acid, ethylene and sugars on the mobilization of storage proteins and carbohydrates in seeds of the tropical tree Sesbania virgata (Leguminosae)

    PubMed Central

    Tonini, Patricia Pinho; Purgatto, Eduardo; Buckeridge, Marcos Silveira

    2010-01-01

    Background and Aims Endospermic legumes are abundant in tropical forests and their establishment is closely related to the mobilization of cell-wall storage polysaccharides. Endosperm cells also store large numbers of protein bodies that play an important role as a nitrogen reserve in this seed. In this work, a systems approach was adopted to evaluate some of the changes in carbohydrates and hormones during the development of seedlings of the rain forest tree Sesbania virgata during the period of establishment. Methods Seeds imbibed abscisic acid (ABA), glucose and sucrose in an atmosphere of ethylene, and the effects of these compounds on the protein contents, α-galactosidase activity and endogenous production of ABA and ethylene by the seeds were observed. Key Results The presence of exogenous ABA retarded the degradation of storage protein in the endosperm and decreased α-galactosidase activity in the same tissue during galactomannan degradation, suggesting that ABA represses enzyme action. On the other hand, exogenous ethylene increased α-galactosidase activity in both the endosperm and testa during galactomannan degradation, suggesting an inducing effect of this hormone on the hydrolytic enzymes. Furthermore, the detection of endogenous ABA and ethylene production during the period of storage mobilization and the changes observed in the production of these endogenous hormones in the presence of glucose and sucrose, suggested a correlation between the signalling pathway of these hormones and the sugars. Conclusions These findings suggest that ABA, ethylene and sugars play a role in the control of the hydrolytic enzyme activities in seeds of S. virgata, controlling the process of storage degradation. This is thought to ensure a balanced flow of the carbon and nitrogen for seedling development. PMID:20705626

  16. Electrochemical study of NO conversion from Fe(II)-EDTA-NO complex on Pt electrodes

    SciTech Connect

    Juzeliunas, E.; Juettner, K.

    1998-01-01

    The Fe(II)-ethylenediaminetetraacetic acid (EDTA)-NO complex formed by interaction of gaseous nitrous oxide (ca. 200 ppm) and Fe(II)-EDTA in aqueous solution was found to be convert3ed electrochemically on platinum electrodes at potentials below ca. {minus}0.6 V{sub SCE}, indicating the cathodic reduction of NO. In addition to the previous studies by which the indirect conversion of NO with dithionite as a redox mediator was confirmed, the present results should elucidate the possibility of the direct electrochemical conversion of NO in mediator-free solutions. To clearly separate this process from other reactions in the system, the electrochemical behavior of Fe(II)-EDTA and Fe(III)-EDTA was studied over a wide potential range at different pH values. Five electrode reactions could be identified, which include the oxidation/reduction of Fe{sup 2+}/Fe{sup 3+} in the EDTA complex, the reduction of EDTA, the reduction of protons, the cathodic deposition of iron, and the anodic decomposition of EDTA. The electrochemical deposition of iron from Fe(II)-EDTA at potentials E < {minus}1.0 V{sub SCE} was confirmed by electrochemical quartz crystal microbalance measurements and energy-dispersive x-ray analysis.

  17. Batch affinity adsorption of His-tagged proteins with EDTA-based chitosan.

    PubMed

    Hua, Weiwei; Lou, Yimin; Xu, Weiyuan; Cheng, Zhixian; Gong, Xingwen; Huang, Jianying

    2016-01-01

    Affinity adsorption purification of hexahistidine-tagged (His-tagged) proteins using EDTA-chitosan-based adsorption was designed and carried out. Chitosan was elaborated with ethylenediaminetetraacetic acid (EDTA), and the resulting polymer was characterized by FTIR, TGA, and TEM. Different metals including Ni(2+), Cu(2+), and Zn(2+) were immobilized with EDTA-chitosan, and their capability to the specific adsorption of His-tagged proteins were then investigated. The results showed that Ni(2+)-EDTA-chitosan and Zn(2+)-EDTA-chitosan had high affinity toward the His-tagged proteins, thus isolating them from protein mixture. The target fluorescent-labeled hexahistidine protein remained its fluorescent characteristic throughout the purification procedure when Zn(2+)-EDTA-chitosan was used as a sorbent, wherein the real-time monitor was performed to examine the immigration of fluorescent-labeled His-tagged protein. Comparatively, Zn(2+)-EDTA-chitosan showed more specific binding ability for the target protein, but with less binding capacity. It was further proved that this purification system could be recovered and reused at least for 5 times and could run on large scales. The presented M(2+)-EDTA-chitosan system, with the capability to specifically bind His-tagged proteins, make the purification of His-tagged proteins easy to handle, leaving out fussy preliminary treatment, and with the possibility of continuous processing and a reduction in operational cost in relation to the costs of conventional processes.

  18. Poly(acrylic acid)/poly(ethylene glycol) adduct for attaining multifunctional cellulosic fabrics.

    PubMed

    Ibrahim, N A; Amr, A; Eid, B M; Mohamed, Z E; Fahmy, H M

    2012-06-20

    Aqueous polymerization of partially neutralized acrylic acid (AA) along with polyethylene glycol (PEG-600) at AA/PEG-600 mass ratio 3/1 using ammonium persulfate as initiator under proper conditions results in formation of PAA/PEG-600 adduct. The structure of the adduct was confirmed by FT-IR spectra. The potential applications of the prepared adduct in: sizing, durable hand building of cotton cellulose, as well as in functional finishing of cellulose containing fabrics, i.e. cotton, viscose and cotton/polyester, with Ag- or TiO2-nanoparticles were investigated. The modified substrates using the prepared adduct showed a remarkable improvement in their sizing, hand building and/or functional properties, i.e. antibacterial, anti-UV, and self cleaning, in addition to durability to wash. TEM images of the prepared nano-particles, SEM images of the untreated and treated substrates, as well as EDX spectra to analyze the surface elemental compositions were examined. The tentative mechanisms were also suggested. PMID:24750770

  19. Leaf Abscission Induced by Ethylene in Water-Stressed Intact Seedlings of Cleopatra Mandarin Requires Previous Abscisic Acid Accumulation in Roots.

    PubMed

    Gomez-Cadenas, A.; Tadeo, F. R.; Talon, M.; Primo-Millo, E.

    1996-09-01

    The involvement of abscisic acid (ABA) in the process of leaf abscission induced by 1-aminocyclopropane-1-carboxylic acid (ACC) transported from roots to shoots in Cleopatra mandarin (Citrus reshni Hort. ex Tan.) seedlings grown under water stress was studied using norflurazon (NF). Water stress induced both ABA (24-fold) and ACC (16-fold) accumulation in roots and arrested xylem flow. Leaf bulk ABA also increased (8-fold), although leaf abscission did not occur. Shortly after rehydration, root ABA and ACC returned to their prestress levels, whereas sharp and transitory increases of ACC (17-fold) and ethylene (10-fold) in leaves and high percentages of abscission (up to 47%) were observed. NF suppressed the ABA and ACC accumulation induced by water stress in roots and the sharp increases of ACC and ethylene observed after rewatering in leaves. NF also reduced leaf abscission (7-10%). These results indicate that water stress induces root ABA accumulation and that this is required for the process of leaf abscission to occur. It was also shown that exogenous ABA increases ACC levels in roots but not in leaves. Collectively, the data suggest that ABA, the primary sensitive signal to water stress, modulates the levels of ethylene, which is the hormonal activator of leaf abscission. This assumption implies that root ACC levels are correlated with root ABA amounts in a dependent way, which eventually links water status to an adequate, protective response such as leaf abscission.

  20. Surface Mechanical and Rheological Behaviors of Biocompatible Poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) and Poly((D,L-lactic acid-ran-glycolic acid-ran-ε-caprolactone)-block-ethylene glycol) (PLGACL-PEG) Block Copolymers at the Air-Water Interface.

    PubMed

    Kim, Hyun Chang; Lee, Hoyoung; Khetan, Jawahar; Won, You-Yeon

    2015-12-29

    Air-water interfacial monolayers of poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) exhibit an exponential increase in surface pressure under high monolayer compression. In order to understand the molecular origin of this behavior, a combined experimental and theoretical investigation (including surface pressure-area isotherm, X-ray reflectivity (XR) and interfacial rheological measurements, and a self-consistent field (SCF) theoretical analysis) was performed on air-water monolayers formed by a PLGA-PEG diblock copolymer and also by a nonglassy analogue of this diblock copolymer, poly((D,L-lactic acid-ran-glycolic acid-ran-caprolactone)-block-ethylene glycol) (PLGACL-PEG). The combined results of this study show that the two mechanisms, i.e., the glass transition of the collapsed PLGA film and the lateral repulsion of the PEG brush chains that occur simultaneously under lateral compression of the monolayer, are both responsible for the observed PLGA-PEG isotherm behavior. Upon cessation of compression, the high surface pressure of the PLGA-PEG monolayer typically relaxes over time with a stretched exponential decay, suggesting that in this diblock copolymer situation, the hydrophobic domain formed by the PLGA blocks undergoes glass transition in the high lateral compression state, analogously to the PLGA homopolymer monolayer. In the high PEG grafting density regime, the contribution of the PEG brush chains to the high monolayer surface pressure is significantly lower than what is predicted by the SCF model because of the many-body attraction among PEG segments (referred to in the literature as the "n-cluster" effects). The end-grafted PEG chains were found to be protein resistant even under the influence of the "n-cluster" effects.

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

    PubMed

    Lahlali, Rachid; McGregor, Linda; Song, Tao; Gossen, Bruce D; Narisawa, Kazuhiko; Peng, Gary

    2014-01-01

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

  2. Potential of Hydrogels Based on Poly(Ethylene Glycol) and Sebacic Acid as Orthopedic Tissue Engineering Scaffolds

    PubMed Central

    Kim, Jinku; Hefferan, Theresa E.; Yaszemski, Michael J.

    2009-01-01

    In this study, the bioactive effects of poly(ethylene glycol) (PEG) sebacic acid diacrylate (PEGSDA) hydrogels with or without RGD peptide modification on osteogenic differentiation and mineralization of marrow stromal cells (MSCs) were examined. In a separate experiment, the ability of PEGSDA hydrogel to serve as a delivery vehicle for bone morphogenetic protein 2 (BMP-2) was also investigated. As a scaffold, the attachment and proliferation of MSCs on PEGSDA hydrogel scaffolds with and without RGD peptide modification was similar to the control, tissue culture polystyrene. In contrast, cells were barely seen on unmodified PEG diacrylate (PEGDA) hydrogel throughout the culture period for up to 21 days. Osteogenic phenotypic expression such as alkaline phosphatase (ALP) of MSCs as well as mineralized calcium content were significantly higher on PEGSDA-based hydrogels than those on the control or PEGDA hydrogels. Potential use of PEGSDA scaffold as a delivery vehicle of osteogenic molecules such as BMP-2 was also evaluated. Initial burst release of BMP-2 from PEGSDA hydrogel scaffold (14.7%) was significantly reduced compared to PEGDA hydrogel scaffold (84.2%) during the first 3 days of a 21-day release period. ALP activity of an osteoblast was significantly higher in the presence of BMP-2 released from PEGSDA hydrogel scaffolds compared to that in the presence of BMP-2 released from PEGDA scaffolds, especially after 6 days of release. Overall, PEGSDA hydrogel scaffolds without further modification may be useful as orthopedic tissue engineering scaffolds as well as local drug carriers for prolonged sustained release of osteoinductive molecules. PMID:19292677

  3. Poly(lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(lactic acid-co-glycolic acid) thermogel as a novel submucosal cushion for endoscopic submucosal dissection.

    PubMed

    Yu, Lin; Xu, Wei; Shen, Wenjia; Cao, Luping; Liu, Yan; Li, Zhaoshen; Ding, Jiandong

    2014-03-01

    Endoscopic submucosal dissection (ESD) is a clinical therapy for early stage neoplastic lesions in the gastrointestinal tract. It is, however, faced with a crucial problem: the high occurrence of perforation. The formation of a submucosal fluid cushion (SFC) via a fluid injection is the best way to avoid perforation, and thus an appropriate biomaterial is vital for this minimally invasive endoscopic technique. In this study, we introduced an injectable thermogel as a novel submucosal injection substance in ESD. The hydrogel synthesized by us was composed of poly(lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymers. The polymer/water system was a low-viscosity fluid at room temperature and thus easily injected, and turned into a non-flowing gel at body temperature after injection. The submucosal injection of the thermogel to create SFCs was performed in both resected porcine stomachs and living minipigs. High mucosal elevation with a clear margin was maintained for a long duration. Accurate en bloc resection was achieved with the assistance of the thermogel. The mean procedure time was strikingly reduced. Meanwhile, no obvious bleeding, perforation and tissue damage were observed. The application of the thermogel not only facilitated the ESD procedure, but also increased the efficacy and safety of ESD. Therefore, the PLGA-PEG-PLGA thermogel provides an excellent submucosal injection system, and has great potential to improve the ESD technique significantly.

  4. 24% Indigenously Prepared Ethylene Diamine Tetra Acetic Acid Compared to Self-Etching Adhesives and their Effect on Shear Bond Strength of Composites in Primary Teeth: An In-vitro Study

    PubMed Central

    Nagar, Priya; Tandil, Yogesh L.; T.P., Chandru; Gupta, Anamika; Kalaria, Devendra; Kumar, Prafful

    2015-01-01

    Background: Over the years, it has been known that 34% phosphoric acid is the benchmark in etchants with the best shear bond strength shown with composites in primary teeth. However, with latest technological advancements and innovations, in order to reduce the number of steps and less damage to the tooth structure, non-rinse conditioner (NRC) & Single-Etch and various other etchants have been tried and tested. These etchants have been found to have shear bond strength comparable to phosphoric acid. In this study, indigenously prepared 24% ethylenediaminetetraacetic acid (EDTA) has been compared with established etchants, as to prove if their shear bond strength was closely related. As it is a well-known fact that EDTA could be less damaging to the enamel during etching and hence can be an alternative for etching of primary teeth. Materials and Methods: For the study 60 caries-free primary molars were used, they were sectioned in the middle, after making area for bonding; the marked area was then etched using different etchants for 30 s. Each of the teeth was then rinsed and bonded with composite resin and thermocycling was done. Shear bond strength testing was done on the composite using Universal Testing Machine. Results: Results of the study showed that phosphoric acid showed the highest bond strength, closely followed by Single Etch (Adper Prompt) and NRC, then by EDTA. Conclusions: About 24% EDTA can be another comparable replacement for phosphoric acid if used with a Single Etch Primer, like Prime and Bond NT on primary teeth. 34% phosphoric acid has the highest bond strength values with composite resin. Single etch followed by NRC has the second and third highest bond strength values, which are comparable to phosphoric acid. PMID:26464540

  5. Gallium-68 EDTA PET/CT for Renal Imaging.

    PubMed

    Hofman, Michael S; Hicks, Rodney J

    2016-09-01

    Nuclear medicine renal imaging provides important functional data to assist in the diagnosis and management of patients with a variety of renal disorders. Physiologically stable metal chelates like ethylenediaminetetraacetic acid (EDTA) and diethylenetriamine penta-acetate (DTPA) are excreted by glomerular filtration and have been radiolabelled with a variety of isotopes for imaging glomerular filtration and quantitative assessment of glomerular filtration rate. Gallium-68 ((68)Ga) EDTA PET usage predates Technetium-99m ((99m)Tc) renal imaging, but virtually disappeared with the widespread adoption of gamma camera technology that was not optimal for imaging positron decay. There is now a reemergence of interest in (68)Ga owing to the greater availability of PET technology and use of (68)Ga to label other radiotracers. (68)Ga EDTA can be used a substitute for (99m)Tc DTPA for wide variety of clinical indications. A key advantage of PET for renal imaging over conventional scintigraphy is 3-dimensional dynamic imaging, which is particularly helpful in patients with complex anatomy in whom planar imaging may be nondiagnostic or difficult to interpret owing to overlying structures containing radioactive urine that cannot be differentiated. Other advantages include accurate and absolute (rather than relative) camera-based quantification, superior spatial and temporal resolution and integrated multislice CT providing anatomical correlation. Furthermore, the (68)Ga generator enables on-demand production at low cost, with no additional patient radiation exposure compared with conventional scintigraphy. Over the past decade, we have employed (68)Ga EDTA PET/CT primarily to answer difficult clinical questions in patients in whom other modalities have failed, particularly when it was envisaged that dynamic 3D imaging would be of assistance. We have also used it as a substitute for (99m)Tc DTPA if unavailable owing to supply issues, and have additionally examined the role of

  6. Chelant extraction of heavy metals from contaminated soils using new selective EDTA derivatives.

    PubMed

    Zhang, Tao; Liu, Jun-Min; Huang, Xiong-Fei; Xia, Bing; Su, Cheng-Yong; Luo, Guo-Fan; Xu, Yao-Wei; Wu, Ying-Xin; Mao, Zong-Wan; Qiu, Rong-Liang

    2013-11-15

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid (EDTA) and its salts can substantially increase heavy metal removal from contaminated soils and have been extensively studied for soil washing. However, EDTA has a poor utilization ratio due to its low selectivity resulting from the competition between soil major cations and trace metal ions for chelation. The present study evaluated the potential for soil washing using EDTA and three of its derivatives: CDTA (trans-1,2-cyclohexanediaminetetraacetic acid), BDTA (benzyldiaminetetraacetic acid), and PDTA (phenyldiaminetetraacetic acid), which contain a cylcohexane ring, a benzyl group, and a phenyl group, respectively. Titration results showed that PDTA had the highest stability constants for Cu(2+) and Ni(2+) and the highest overall selectivity for trace metals over major cations. Equilibrium batch experiments were conducted to evaluate the efficacy of the EDTA derivatives at extracting Cu(2+), Zn(2+), Ni(2+), Pb(2+), Ca(2+), and Fe(3+) from a contaminated soil. At pH 7.0, PDTA extracted 1.5 times more Cu(2+) than did EDTA, but only 75% as much Ca(2+). Although CDTA was a strong chelator of heavy metal ions, its overall selectivity was lower and comparable to that of EDTA. BDTA was the least effective extractant because its stability constants with heavy metals were low. PDTA is potentially a practical washing agent for soils contaminated with trace metals.

  7. 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing rhizobacteria protect Ocimum sanctum plants during waterlogging stress via reduced ethylene generation.

    PubMed

    Barnawal, Deepti; Bharti, Nidhi; Maji, Deepamala; Chanotiya, Chandan Singh; Kalra, Alok

    2012-09-01

    Ocimum sanctum grown as rain-fed crop, is known to be poorly adapted to waterlogged conditions. Many a times the crop suffers extreme damages because of anoxia and excessive ethylene generation due to waterlogging conditions present under heavy rain. The usefulness of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing plant growth promoting rhizobacteria was investigated under waterlogging stress. The comparison of herb yield and stress induced biochemical changes of waterlogged and non-waterlogged plants with and without ACC deaminase-containing microbiological treatments were monitored in this study. Ten plant growth promoting rhizobacteria strains containing ACC-deaminase were isolated and characterized. Four selected isolates Fd2 (Achromobacter xylosoxidans), Bac5 (Serratia ureilytica), Oci9 (Herbaspirillum seropedicae) and Oci13 (Ochrobactrum rhizosphaerae) had the potential to protect Ocimum plants from flood induced damage under waterlogged glass house conditions. Pot experiments were conducted to evaluate the potential of these ACC deaminase-containing selected strains for reducing the yield losses caused by waterlogging conditions. Bacterial treatments protected plants from waterlogging induced detrimental changes like stress ethylene production, reduced chlorophyll concentration, higher lipid peroxidation, proline concentration and reduced foliar nutrient uptake. Fd2 (A. xylosoxidans) induced maximum waterlogging tolerance as treated waterlogged plants recorded maximum growth and herb yield (46.5% higher than uninoculated waterlogged plants) with minimum stress ethylene levels (53% lower ACC concentration as compared to waterlogged plants without bacterial inoculation) whereas under normal non-waterlogged conditions O. rhizosphaerae was most effective in plant growth promotion. PMID:22846334

  8. 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing rhizobacteria protect Ocimum sanctum plants during waterlogging stress via reduced ethylene generation.

    PubMed

    Barnawal, Deepti; Bharti, Nidhi; Maji, Deepamala; Chanotiya, Chandan Singh; Kalra, Alok

    2012-09-01

    Ocimum sanctum grown as rain-fed crop, is known to be poorly adapted to waterlogged conditions. Many a times the crop suffers extreme damages because of anoxia and excessive ethylene generation due to waterlogging conditions present under heavy rain. The usefulness of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing plant growth promoting rhizobacteria was investigated under waterlogging stress. The comparison of herb yield and stress induced biochemical changes of waterlogged and non-waterlogged plants with and without ACC deaminase-containing microbiological treatments were monitored in this study. Ten plant growth promoting rhizobacteria strains containing ACC-deaminase were isolated and characterized. Four selected isolates Fd2 (Achromobacter xylosoxidans), Bac5 (Serratia ureilytica), Oci9 (Herbaspirillum seropedicae) and Oci13 (Ochrobactrum rhizosphaerae) had the potential to protect Ocimum plants from flood induced damage under waterlogged glass house conditions. Pot experiments were conducted to evaluate the potential of these ACC deaminase-containing selected strains for reducing the yield losses caused by waterlogging conditions. Bacterial treatments protected plants from waterlogging induced detrimental changes like stress ethylene production, reduced chlorophyll concentration, higher lipid peroxidation, proline concentration and reduced foliar nutrient uptake. Fd2 (A. xylosoxidans) induced maximum waterlogging tolerance as treated waterlogged plants recorded maximum growth and herb yield (46.5% higher than uninoculated waterlogged plants) with minimum stress ethylene levels (53% lower ACC concentration as compared to waterlogged plants without bacterial inoculation) whereas under normal non-waterlogged conditions O. rhizosphaerae was most effective in plant growth promotion.

  9. Arabidopsis paired amphipathic helix proteins SNL1 and SNL2 redundantly regulate primary seed dormancy via abscisic acid-ethylene antagonism mediated by histone deacetylation.

    PubMed

    Wang, Zhi; Cao, Hong; Sun, Yongzhen; Li, Xiaoying; Chen, Fengying; Carles, Annaick; Li, Yong; Ding, Meng; Zhang, Cun; Deng, Xin; Soppe, Wim J J; Liu, Yong-Xiu

    2013-01-01

    Histone (de)acetylation is a highly conserved chromatin modification that is vital for development and growth. In this study, we identified a role in seed dormancy for two members of the histone deacetylation complex in Arabidopsis thaliana, SIN3-LIKE1 (SNL1) and SNL2. The double mutant snl1 snl2 shows reduced dormancy and hypersensitivity to the histone deacetylase inhibitors trichostatin A and diallyl disulfide compared with the wild type. SNL1 interacts with HISTONE DEACETYLASE19 in vitro and in planta, and loss-of-function mutants of SNL1 and SNL2 show increased acetylation levels of histone 3 lysine 9/18 (H3K9/18) and H3K14. Moreover, SNL1 and SNL2 regulate key genes involved in the ethylene and abscisic acid (ABA) pathways by decreasing their histone acetylation levels. Taken together, we showed that SNL1 and SNL2 regulate seed dormancy by mediating the ABA-ethylene antagonism in Arabidopsis. SNL1 and SNL2 could represent a cross-link point of the ABA and ethylene pathways in the regulation of seed dormancy.

  10. Anaerobic Biotransformation and Mobility of Pu and PuEDTA

    SciTech Connect

    Xun, Luying

    2005-06-01

    Although our goal is to isolate anaerobic EDTA degraders, we initiated the experiments to include nitrilotriacetate (NTA), which is a structure homologue of EDTA. All the aerobic EDTA degraders can degrade NTA, but the isolated NTA degraders cannot degrade EDTA. Since NTA is a simpler structure homologue, it is likely that EDTA-degrading ability is evolved from NTA degradation. This hypothesis is further supported from our characterization of EDTA and NTA-degrading enzymes and genes (J. Bact. 179:1112-1116; and Appl. Environ. Microbiol. 67:688-695). The EDTA monooxygenase and NTA monooxygenase are highly homologous. EDTA monooxygenase can use both EDTA and NTA as substrates, but NTA monooxygenase can only use NTA as a substrate. Thus, we put our effort to isolate both NTA and EDTA degraders. In case, an anaerobic EDTA degrader is not immediately enriched, we will try to evolve the NTA degraders to use EDTA. Both aerobic and anaerobic enrichment cultures were set.

  11. Poly(lactic acid)-poly(ethylene glycol) nanoparticles as new carriers for the delivery of plasmid DNA.

    PubMed

    Perez, C; Sanchez, A; Putnam, D; Ting, D; Langer, R; Alonso, M J

    2001-07-10

    The purpose of the present work was to produce and characterize poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) nanoparticles (size lower than 300 nm) containing a high loading of plasmid DNA in a free form or co-encapsulated with either poly(vinyl alcohol) (PVA) or poly(vinylpyrrolidone) (PVP). The plasmid alone or with PVA or PVP was encapsulated by two different techniques: an optimized w/o/w emulsion-solvent evaporation technique as well as by a new w/o emulsion-solvent diffusion technique. Particle size, zeta potential, plasmid DNA loading and in vitro release were determined for the three plasmid-loaded formulations. The influence of the initial plasmid loadings (5, 10, 20 microg plasmid DNA/mg PLA-PEG) on those parameters was also investigated. The plasmid loaded into the nanoparticles and released in vitro was quantified by fluorimetry and the different molecular forms were identified by gel electrophoresis. PLA-PEG nanoparticles containing plasmid DNA in a free form or co-encapsulated with PVA or PVP were obtained in the range size of 150-300 nm and with a negative zeta potential, both parameters being affected by the preparation technique. Encapsulation efficiencies were high irrespective of the presence of PVA or PVP (60-90%) and were slightly affected by the preparation technique and by the initial loading. The final plasmid DNA loading in the nanoparticles was up to 10-12 microg plasmid DNA/mg polymer. Plasmid DNA release kinetics varied depending on the plasmid incorporation technique: nanoparticles prepared by the w/o diffusion technique released their content rapidly whereas those obtained by the w/o/w showed an initial burst followed by a slow release for at least 28 days. No significant influence of the plasmid DNA loading and of the co-encapsulation of PVP or PVA on the in vitro release rate was observed. In all cases the conversion of the supercoiled form to the open circular and linear forms was detected. In conclusion, plasmid DNA can be

  12. Effects of molecular architecture on crystallization behavior of poly(lactic acid) and random ethylene-vinyl acetate copolymers

    NASA Astrophysics Data System (ADS)

    Kalish, Jeffrey P.

    2011-07-01

    The relationship between polymer chain architecture, crystallization behavior, and morphology formation was investigated. The structures formed are highly dependent on chain configuration and crystallization kinetics. Poly(lactic acid) (PLA) and Poly(ethylene-co-vinyl acetate) (EVA) random copolymers were studied. Sample characterization was performed using a variety of techniques, including spectroscopy, scattering, and calorimetry. In PLA, structural differences between alpha' and alpha crystalline phases were analyzed using cryogenic infrared and Raman spectroscopy. Compared to the alpha crystal, the alpha' crystal has slightly looser packing and weaker intermolecular interactions involving carbonyl and methyl functional groups. Simulations in conjunction with Raman scattering analyzed the conformational distortion of the alpha' phase. The conformation of an alpha' chain was determined to have tg't-10/3 conformation with tg't-3/1 units randomly distributed along the chain. Departure of the O-C(alpha); dihedral angle was also confirmed. The structural disorder leads to different thermal properties for alpha' and alpha crystalline forms, which was quantified by measuring the enthalpic change at melting for both crystals (delta H (alpha') = 57 +/- 3 J/g and delta H (alpha) = 96 +/- 3 J/g). The transformation from alpha' to alpha and the mechanism of order formation in PLA were also elucidated. The relationship between chain configuration of EVA random copolymers and crystallization behavior was established. For three different EVA samples, the distribution of methylene sequences was calculated and compared to a distribution of crystallite sizes formed. This comparison revealed that only a small fraction of the total methylene segments present actually crystallized. Cocrystallization with highly mobile oligomers was explored to enhance the crystallization of EVA copolymers. When blended, EVA28 (28 weight percentage) cocrystallizes with C36H74 n-alkane resulting in

  13. Stability of tranexamic acid in 0.9% sodium chloride, stored in type 1 glass vials and ethylene/propylene copolymer plastic containers.

    PubMed

    McCluskey, Susan V; Sztajnkrycer, Matthew D; Jenkins, Donald A; Zietlow, Scott P; Berns, Kathleen S; Park, Myung S

    2014-01-01

    Tranexamic acid has recently been demonstrated to decrease all-cause mortality and deaths due to hemorrhage in trauma patients. The optimal administration of tranexamic acid is within one hour of injury, but not more than three hours from the time of injury. To aid with timely administration, a premixed solution of 1 gram tranexamic acid and 0.9% sodium chloride was proposed to be stocked as a medication in both the aeromedical transport helicopters and Emergency Department at Mayo Clinic Hospital--Rochester Saint Marys Campus. Since no published stability data exists for tranexamic acid diluted with 0.9% sodium chloride, this study was undertaken to determine the stability of tranexamic acid diluted with 0.9% sodium chloride while being stored in two types of containers. Stability was determined through the use of a stability-indicating high-performance liquid reverse phase chromatography assay, pH, and visual tests. Tranexamic acid solutions of 1 gram in 0.9% sodium chloride 65 mL were studied at predetermined intervals for 90 days in ethylene/propylene copolymer plastic containers, protected from light, and at both controlled room and refrigerated temperatures. Tranexamic acid solutions of 1 gram in 0.9% sodium chloride 50 mL were studied at predetermined intervals for 180 days in clear Type 1 borosilicate glass vials sealed with intact elastomeric, Flourotec-coated stoppers, stored protected from light at controlled room temperature. Solutions stored in the ethylene/propylene copolymer plastic containers at both storage temperatures maintained at least 98% of initial potency throughout the 90-day study period. Solutions stored in glass vials at controlled room temperature maintained at least 92% of initial potency throughout the 180-day study period. Visual and pH tests revealed stable, clear, colorless, and particulate-free solutions throughout the respective study periods.

  14. Integration of Ethylene and Jasmonic Acid Signaling Pathways in the Expression of Novel Maize Defense Protein Mir1-CP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In plants, ethylene (ET) and jasmonate (JA) control the defense responses to multiple stressors, including insect predation. Among the defense proteins known to be regulated by ET, is maize insect resistance 1-cysteine protease (Mir1-CP). This protein is constitutively expressed in the insect resi...

  15. Integration of ethylene and jasmonic acid signaling pathways in the expression of maize defense protein Mir1-CP.

    PubMed

    Ankala, A; Luthe, D S; Williams, W P; Wilkinson, J R

    2009-12-01

    In plants, ethylene and jasmonate control the defense responses to multiple stressors, including insect predation. Among the defense proteins known to be regulated by ethylene is maize insect resistance 1-cysteine protease (Mir1-CP). This protein is constitutively expressed in the insect-resistant maize (Zea mays) genotype Mp708; however, its abundance significantly increases during fall armyworm (Spodoptera frugiperda) herbivory. Within 1 h of herbivory by fall armyworm, Mir1-CP accumulates at the feeding site and continues to increase in abundance until 24 h without any increase in its transcript (mir1) levels. To resolve this discrepancy and elucidate the role of ethylene and jasmonate in the signaling of Mir1-CP expression, the effects of phytohormone biosynthesis and perception inhibitors on Mir1-CP expression were tested. Immunoblot analysis of Mir1-CP accumulation and quantitative reverse-transcriptase polymerase chain reaction examination of mir1 levels in these treated plants demonstrate that Mir1-CP accumulation is regulated by both transcript abundance and protein expression levels. The results also suggest that jasmonate functions upstream of ethylene in the Mir1-CP expression pathway, allowing for both low-level constitutive expression and a two-stage defensive response, an immediate response involving Mir1-CP accumulation and a delayed response inducing mir1 transcript expression.

  16. Ethylene glycol

    Integrated Risk Information System (IRIS)

    Ethylene glycol ; CASRN 107 - 21 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  17. Ethylene diamine

    Integrated Risk Information System (IRIS)

    Ethylene diamine ; CASRN 107 - 15 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  18. Enhanced phytoextraction of Cu, Pb, Zn and Cd with EDTA and EDDS.

    PubMed

    Luo, Chunling; Shen, Zhenguo; Li, Xiangdong

    2005-03-01

    Chemically enhanced phytoextraction has been proposed as an effective approach to removing heavy metals from contaminated soil through the use of high biomass plants. Using pot experiments, the effects of the application of EDTA, EDDS and citric acid on the uptake of Cu, Pb, Zn and Cd by corn (Zea mays L. cv. Nongda 108) and bean (Phaseolus vulgaris L. white bean) plants were studied. The results showed that EDDS was more effective than EDTA at increasing the concentration of Cu in corn and beans. The application of 5 mmol kg-1 soil EDDS to soil significantly increased concentrations of Cu in shoots, with maximum levels of 2060 and 5130 mg kg-1 DW in corn and beans, respectively, which were 45- and 135-fold higher than that in the corresponding control plants to which chelate had not been applied. Concentrations of Zn in shoots were also higher in the plants treated with EDDS than in those treated with EDTA. For Pb and Cd, EDDS was less effective than EDTA. The maximum Cu phytoextraction was found with the EDDS treatment. The application of EDTA and EDDS also significantly increased the shoot-to-root ratios of the concentrations of Cu, Pb, Zn and Cd in both plant species. The results of metal extraction with chelates showed that EDDS was more efficient at solubilizing Cu and Zn than EDTA, and that EDTA was better at solubilizing Pb and Cd than EDDS.

  19. Adsorption and dissociation of Co-EDTA complexes in iron oxide-containing subsurface sands

    SciTech Connect

    Zachara, J.M.; Smith, S.C.; Kuzel, L.S.

    1995-12-31

    The sorption of Co(II)EDTA{sup 2-} (where EDTA is ethylenediaminetetracetic acid) was investigated on goethite and on eight sand-textured Quaternary and Pliocene fluvial sediments. Dual-label tracer techniques were used to follow the distribution of {sup 60}Co(II)- {sup 14}C/EDTA added as the performed 1:1, Co(II) EDTA{sup 2-} complex. Sorption experiments were performed with fixed concentrations of Co(II)EDTA{sup 2-} (10{sup -5} mol/L) and variable pH (all materials), and fixed pH (4.4) with variable Co(II)EDTA{sup 2-} concentrations (two materials), using solids concentrations of 0.5 g/L for goethite and 500 g/L for the sediments and electrolyte concentrations of 0.003 and 0.03 (geothite only) mol/L Ca(ClO{sub 4}){sub 2}. Aqueous Fe{sub aq}{sup 3+} and Al{sub aq}{sup 3+} were measured at the time of the sorption determination. On goethite, Co(II)EDTA{sup 2-} exhibited anion-like sorption, increasing with decreasing pH. Increasing electrolyte concentration decreased sorption, indicating a weak, ion-pair type surface complex. Below pH 6, however, the sorption chemistry of Co{sup 2+} and EDTA{sup 4-} became complex and disparate as a result of Co(II)EDTA{sup 2-} dissociation. Dissociation was driven by exchange with Fe{sub aq}{sup 3+}. A nonelectrostatic surface complexation model that explicitly considered the Fe{sup 3+} -Co(II)EDTA{sup 2-} exchange reaction was able to adequately describe the sorption data using surface complexes with Co(II)EDTA{sup 2-}, FeEDTA{sup -}, and Co{sup 2+}. Iron oxides were a dominant grain-coating phase on over half the sorbents, and X-ray diffraction (XRD), chemical extraction, and microscopic techniques documented the presence of poorly crystalline forms as well as geothite, hematite, and feroxyhite. The coupled adsorption, dissolution, and dissociation process will cause complex distance-variant speciation and retardation behavior for Co(II)EDTA{sup 2-} in subsurface environments. 58 refs., 14 figs., 6 tabs.

  20. Extension of a PBPK model for ethylene glycol and glycolic acid to include the competitive formation and clearance of metabolites associated with kidney toxicity in rats and humans

    SciTech Connect

    Corley, R.A.; Saghir, S.A.; Bartels, M.J.; Hansen, S.C.; Creim, J.; McMartin, K.E.; Snellings, W.M.

    2011-02-01

    A previously developed PBPK model for ethylene glycol and glycolic acid was extended to include glyoxylic acid, oxalic acid, and the precipitation of calcium oxalate that is associated with kidney toxicity in rats and humans. The development and evaluation of the PBPK model was based upon previously published pharmacokinetic studies coupled with measured blood and tissue partition coefficients and rates of in vitro metabolism of glyoxylic acid to oxalic acid, glycine and other metabolites using primary hepatocytes isolated from male Wistar rats and humans. Precipitation of oxalic acid with calcium in the kidneys was assumed to occur only at concentrations exceeding the thermodynamic solubility product for calcium oxalate. This solubility product can be affected by local concentrations of calcium and other ions that are expressed in the model using an ion activity product estimated from toxicity studies such that calcium oxalate precipitation would be minimal at dietary exposures below the NOAEL for kidney toxicity in the sensitive male Wistar rat. The resulting integrated PBPK predicts that bolus oral or dietary exposures to ethylene glycol would result in typically 1.4-1.6-fold higher peak oxalate levels and 1.6-2-fold higher AUC's for calcium oxalate in kidneys of humans as compared with comparably exposed male Wistar rats over a dose range of 1-1000 mg/kg. The converse (male Wistar rats predicted to have greater oxalate levels in the kidneys than humans) was found for inhalation exposures although no accumulation of calcium oxalate is predicted to occur until exposures are well in excess of the theoretical saturated vapor concentration of 200 mg/m{sup 3}. While the current model is capable of such cross-species, dose, and route-of-exposure comparisons, it also highlights several areas of potential research that will improve confidence in such predictions, especially at low doses relevant for most human exposures.

  1. Inhibition on Candida albicans biofilm formation using divalent cation chelators (EDTA).

    PubMed

    Ramage, Gordon; Wickes, Brian L; López-Ribot, José L

    2007-12-01

    Candida albicans can readily form biofilms on both inanimate and biological surfaces. In this study we investigated a means of inhibiting biofilm formation using EDTA (Ethylenediaminetetra-acetic acid), a divalent cation chelating agent, which has been shown to affect C. albicans filamentation. Candida albicans biofilms were formed in 96-well microtitre plates. Cells were allowed to adhere for 1, 2, and 4 h at 37 degrees C, washed in PBS, and then treated with different concentrations of EDTA (0, 2.5, 25, and 250 mM). EDTA was also added to the standardized suspension prior to adding to the microtiter plate and to a preformed 24 h biofilm. All plates were then incubated at 37 degrees C for an additional 24 h to allow for biofilm formation. The extent and characteristics of biofilm formation were then microscopically assessed and with a semi-quantitative colorimetric technique based on the use of an XTT-reduction assay. Northern blot analysis of the hyphal wall protein (HWP1) expression was also monitored in planktonic and biofilm cells treated with EDTA. Microscopic analysis and colorimetric readings revealed that filamentation and biofilm formation were inhibited by EDTA in a concentration dependent manner. However, preformed biofilms were minimally affected by EDTA (maximum of 31% reduction at 250 mM). The HWP1 gene expression was reduced in EDTA-treated planktonic and biofilm samples. These results indicate that EDTA inhibits C. albicans biofilm formation are most likely through its inhibitory effect on filamentation and indicates the potential therapeutic effects of EDTA. This compound may serve a non-toxic means of preventing biofilm formation on infections with a C. albicans biofilm etiology. PMID:17909983

  2. Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks.

    PubMed

    Zhang, Daoyong; Lee, Duu-Jong; Pan, Xiangliang

    2013-01-01

    Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks. PMID:23247408

  3. Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks.

    PubMed

    Zhang, Daoyong; Lee, Duu-Jong; Pan, Xiangliang

    2013-01-01

    Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks.

  4. Chitosan-EDTA new combination is a promising candidate for treatment of bacterial and fungal infections.

    PubMed

    El-Sharif, Amany A; Hussain, Mohamed H M

    2011-03-01

    Chitosan is an attractive preparation widely used as a pharmaceutical excipient. This study aimed to evaluate the antimicrobial activities of chitosan derivatives, EDTA, and the newly developed chitosan-EDTA combination against Gram-negative and Gram-positive bacteria as well as Candida albicans. Antimicrobial activity was studied. Both minimal Inhibitory Concentrations (MIC) and minimal biocidal concentrations (MBC) were determined. Chitosan acetic acid recorded lower MIC values against Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans than those exhibited by EDTA. EDTA failed to have inhibitory activity against Enterococcus faecalis as well as MBC against any of the studied microorganisms. Chitosan acetic acid's MBC were recorded to all examined species. Checkerboard assay results indicated a synergistic antimicrobial activity of the new combination against Staphylococcus aureus and an additive effect against other microorganisms. Moreover, a short microbial exposure to chitosan-EDTA (20-30 min) caused complete eradication. Due to the continuous emergence of resistant strains, there is an urgent need to discover new antimicrobial agents. Our findings suggest the use of chitosan as an enhancing agent with antibacterial and antifungal properties in combination with EDTA in pharmaceutical preparations. PMID:20963418

  5. Improved biocompatibility of poly (styrene-b-(ethylene-co-butylene)-b-styrene) elastomer by a surface graft polymerization of hyaluronic acid.

    PubMed

    Li, Xiaomeng; Luan, Shifang; Shi, Hengchong; Yang, Huawei; Song, Lingjie; Jin, Jing; Yin, Jinghua; Stagnaro, Paola

    2013-02-01

    Hyaluronic acid (HA) is an important component of extracellular matrix (ECM) in many tissues, providing a hemocompatible and supportive environment for cell growth. In this study, glycidyl methacrylate-hyaluronic acid (GMHA) was first synthesized and verified by proton nuclear magnetic resonance ((1)H NMR) spectroscopy. GMHA was then grafted to the surface of biomedical elastomer poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) via an UV-initiated polymerization, monitored by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The further improvement of biocompatibility of the GMHA-modified SEBS films was assessed by platelet adhesion experiments and in vitro response of murine osteoblastic cell line MC-3T3-E1 with the virgin SEBS surface as the reference. It showed that the surface modification with HA strongly resisted platelet adhesion whereas improved cell-substrate interactions.

  6. Electrospraying and Electrospinning of Polymers for Biomedical Applications. Poly(Lactic-Co-Glycolic Acid) and Poly(Ethylene-Co-Vinylacetate). Appendix 2

    NASA Technical Reports Server (NTRS)

    Stitzel, Joel D.; Bowlin, Gary L.; Mansfield, Kevin; Wnek, Gary E.; Simpson, David G.

    2000-01-01

    Significant opportunities exist for the processing of polymers (homopolymers and blends) using electric fields. Specific attention is given here to electrospinning, but we note that electroaerosol formation and field-modulated film casting represent additional processing options. Of particular interest is the ability to generate polymer fibers of sub-micron dimensions using electrospinning, down to about 0.05 microns (50 nm), a size range that has been traditionally difficult to access. In our work, poly(lactic-co-glycolic acid), PLA/PGA, poly(lactic acid) PLA, and poly(ethylene-co-vinylacetate) (PEVA) have been deposited from solutions in methylene chloride or chloroform by electrospraying or electrospinning to afford morphologically tailored materials for tissue engineering and related applications. Low solution concentrations tend to favor electrostatic spraying ('electro-aerosolization') while higher concentrations lead to spinning on fibrous mats. Preliminary observations of muscle cell growth on PLA electrospun mats are reported.

  7. 21 CFR 172.120 - Calcium disodium EDTA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium disodium EDTA. 172.120 Section 172.120... CONSUMPTION Food Preservatives § 172.120 Calcium disodium EDTA. The food additive calcium disodium EDTA... EDTA (disodium ethylenediaminetetraacetate) in the following foods at not to exceed, in...

  8. 21 CFR 172.120 - Calcium disodium EDTA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium disodium EDTA. 172.120 Section 172.120... CONSUMPTION Food Preservatives § 172.120 Calcium disodium EDTA. The food additive calcium disodium EDTA... EDTA (disodium ethylenediaminetetraacetate) in the following foods at not to exceed, in...

  9. Enhanced photocatalytic activity of chromium(VI) reduction and EDTA oxidization by photoelectrocatalysis combining cationic exchange membrane processes.

    PubMed

    Hsu, Hung-Te; Chen, Shiao-Shing; Tang, Yi-Fang; Hsi, Hsing-Cheng

    2013-03-15

    A novel technology of photoelectrocatalysis (PEC) combining with cationic exchange membrane (CEM) was proposed for simultaneous reduction of chromium(VI) and oxidization of EDTA. The application of CEM was used to enhance the efficiency for prevention of the re-oxidation of reduced chromium with the electron-hole pairs. In this study, effects of current density, pH, TiO2 dosage, hydraulic retention time (HRT), light intensity and EDTA/Cr(VI) molar ratio were all investigated. The results showed that the optimum conversion efficiency occurred at 4mA/cm(2) with the presence of CEM. Higher conversion efficiencies were observed at lower pH due to the electrostatic attractions between positive charged TiOH2(+), and negatively charged Cr(VI) and EDTA. The optimum TiO2 loading of 1g/L was depended mainly on the acidic pH range, especially at higher HRT and irradiation intensity. In addition, higher EDTA/Cr(VI) molar ratio enhanced the reduction efficiency of Cr(VI), indicating EDTA plays the role of hole scavenger in this system. Moreover, incomplete EDTA decomposition contributes to the occurrence of intermediates, including nitrilotriacetic acid, iminodiacetic acid, glycine, oxamic acid, lyoxylic acid, oxalic acid, acetic acid and formic acid, as identified by GC/MS. Consequently, transformation pathway was determined from these analyzed byproducts and molecular orbital package analysis.

  10. The transcriptional response of apple alcohol acyltransferase (MdAAT2) to salicylic acid and ethylene is mediated through two apple MYB TFs in transgenic tobacco.

    PubMed

    Li, Peng-Cheng; Yu, Shao-Wei; Shen, Jin; Li, Qing-Qing; Li, Da-Peng; Li, De-Quan; Zheng, Cheng-Chao; Shu, Huai-Rui

    2014-08-01

    Volatile esters are major factors affecting the aroma of apple fruits, and alcohol acyltransferases (AATs) are key enzymes involved in the last steps of ester biosynthesis. The expression of apple AAT (MdAAT2) is known to be induced by salicylic acid (SA) or ethylene in apple fruits, although the mechanism of its transcriptional regulation remains elusive. In this study, we reveal that two apple transcription factors (TFs), MdMYB1 and MdMYB6, are involved in MdAAT2 promoter response to SA and ethylene in transgenic tobacco. According to electrophoretic mobility shift assays, MdMYB1 or MdMYB6 can directly bind in vitro to MYB binding sites in the MdAAT2 promoter. In vivo, overexpression of the two MYB TFs can greatly enhance MdAAT2 promoter activity, as demonstrated by dual luciferase reporter assays in transgenic tobacco. In contrast to the promoter of MdMYB1 or MdMYB6, the MdAAT2 promoter cannot be induced by SA or ethephon (ETH) in transgenic tobacco, even in stigmas in which the MdAAT2 promoter can be highly induced under normal conditions. However, the induced MYB TFs can dramatically enhance MdAAT2 promoter activity under SA or ETH treatment. We conclude that MdMYB1 and MdMYB6 function in MdAAT2 responses to SA and ethylene in transgenic tobacco, suggesting that a similar regulation mechanism may exist in apple.

  11. The Arabidopsis Ethylene/Jasmonic Acid-NRT Signaling Module Coordinates Nitrate Reallocation and the Trade-Off between Growth and Environmental Adaptation[W][OPEN

    PubMed Central

    Zhang, Guo-Bin; Yi, Hong-Ying

    2014-01-01

    Stresses decouple nitrate assimilation and photosynthesis through stress-initiated nitrate allocation to roots (SINAR), which is mediated by the nitrate transporters NRT1.8 and NRT1.5 and functions to promote stress tolerance. However, how SINAR communicates with the environment remains unknown. Here, we present biochemical and genetic evidence demonstrating that in Arabidopsis thaliana, ethylene (ET) and jasmonic acid (JA) affect the crosstalk between SINAR and the environment. Electrophoretic mobility shift assays and chromatin immunoprecipitation assays showed that ethylene response factors (ERFs), including OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59, bind to the GCC boxes in the NRT1.8 promoter region, while ETHYLENE INSENSITIVE3 (EIN3) binds to the EIN3 binding site motifs in the NRT1.5 promoter. Genetic assays showed that cadmium and sodium stresses initiated ET/JA signaling, which converged at EIN3/EIN3-Like1 (EIL1) to modulate ERF expression and hence to upregulate NRT1.8. By contrast, ET and JA signaling mediated the downregulation of NRT1.5 via EIN3/EIL1 and other, unknown component(s). SINAR enhanced stress tolerance and decreased plant growth under nonstressed conditions through the ET/JA-NRT1.5/NRT1.8 signaling module. Interestingly, when nitrate reductase was impaired, SINAR failed to affect either stress tolerance or plant growth. These data suggest that SINAR responds to environmental conditions through the ET/JA-NRT signaling module, which further modulates stress tolerance and plant growth in a nitrate reductase-dependent manner. PMID:25326291

  12. Changes in haematology measurements with the Sysmex XT-2000iV during storage of feline blood sampled in EDTA or EDTA plus CTAD.

    PubMed

    Granat, Fanny; Geffré, Anne; Bourgès-Abella, Nathalie; Braun, Jean-Pierre; Trumel, Catherine

    2013-06-01

    In veterinary medicine a complete blood cell count (CBC) cannot always be performed within 24 h as usually recommended, particularly for specimens shipped to a reference laboratory. This raises the question of the stability of the variables, especially in ethylenediamine tetra-acetic acid (EDTA) feline blood specimens, known to be prone to in vitro platelet aggregation. Citrate, theophylline, adenosine and dipyridamole (CTAD) has been reported to limit platelet aggregation in feline blood specimens. The aim of this study was to measure the stability of the haematological variables and the platelet aggregation score in EDTA and EDTA plus CTAD (EDCT) feline blood specimens during 48 h of storage at room temperature. Forty-six feline EDTA and EDCT blood specimens were analysed with a Sysmex XT-2000iV analyser, and the platelet count and score of platelet aggregation were estimated immediately and after 24 and 48 h of storage. A significant increase in mean corpuscular volume, haematocrit, reticulocyte and eosinophil counts, and a significant decrease in mean corpuscular haemoglobin concentration and monocyte count were observed. Haemoglobin, mean corpuscular haemoglobin, and red blood cell, white blood cell, neutrophil and lymphocyte counts remained stable. Changes in reticulocyte indexes with time (low fluorescence ratio, medium fluorescence ratio, high fluorescence ratio and immature reticulocyte fraction) were not significant. Changes were generally more pronounced in EDTA than in EDCT. Platelet aggregation decreased markedly in initially highly aggregated EDTA specimens, and increased slightly in initially non- or mildly-aggregated EDTA or EDCT specimens. Platelet counts increased and decreased, or remained stable, respectively. CTAD can reduce storage-induced changes of the haematological variables in feline samples, thus improving the reliability of a CBC and limiting clinical misinterpretations.

  13. Fast determination of ethylene glycol, 1,2-propylene glycol and glycolic acid in blood serum and urine for emergency and clinical toxicology by GC-FID.

    PubMed

    Hložek, Tomáš; Bursová, Miroslava; Čabalaa, Radomír

    2014-12-01

    A simple, cost effective, and fast gas chromatography method with flame ionization detection (GC-FID) for simultaneous measurement of ethylene glycol, 1,2-propylene glycol and glycolic acid was developed and validated for clinical toxicology purposes. This new method employs a relatively less used class of derivatization agents - alkyl chloroformates, allowing the efficient and rapid derivatization of carboxylic acids within seconds while glycols are simultaneously derivatized by phenylboronic acid. The entire sample preparation procedure is completed within 10 min. To avoid possible interference from naturally occurring endogenous acids and quantitation errors 3-(4-chlorophenyl) propionic acid was chosen as an internal standard. The significant parameters of the derivatization have been found using chemometric procedures and these parameters were optimized using the face-centered central composite design. The calibration dependence of the method was proved to be quadratic in the range of 50-5000 mg mL(-1), with adequate accuracy (92.4-108.7%) and precision (9.4%). The method was successfully applied to quantify the selected compounds in serum of patients from emergency units.

  14. Degradation of the ferric chelate of EDTA by a pure culture of an Agrobacterium sp

    SciTech Connect

    Lauff, J.J.; Coogan, L.A.; Breitfeller, J.M. ); Steele, D.B. )

    1990-11-01

    A pure culture of an Agrobacterium sp. (deposited as ATCC 55002) the mineralizes the ferric chelate of EDTA (ferric-EDTA) was isolated by selective enrichment from a treatment facility receiving industrial waste containing ferric-EDTA. The isolated grew on ferric-EDTA as the sole carbon source at concentrations exceeding 100 mM. As the degradation proceeded, carbon dioxide, ammonia, and an unidentified metabolite(s) were produced; the pH increased, and iron was precipitated from solution. The maximum rate of degradation observed with sodium ferric-EDTA as the substrate was 24 mM/day. At a substrate concentration of 35 mM, 90% of the substrate was degraded in 3 days and 70% of the associated chemical oxygen demand was removed from solution. Less than 15% of the carbon initially present was incorporated into the cell mass. Significant growth of this strain was not observed with uncomplexed EDTA as the sole carbon source at comparable concentrations; however, the ferric chelate of propylenediaminetetraacetic acid (ferric-PDTA) did support growth.

  15. Quantifying the influence of EDTA on polymer nanoparticle deposition and retention in an iron-oxide-coated sand column.

    PubMed

    Yang, Xinyao; Liang, Dongxu; Deng, Shihuai

    2012-09-01

    Ethylenediaminotetraacetic acid (EDTA) occurring in groundwater aquifers complicates the prediction of nanoparticle movement in the porous medium. This paper demonstrates an approach combining Triple Pulse Experiments (TPEs) and numerical modelling to quantify the influence of EDTA on the deposition and retention of polymer nanoparticles in a water-saturated column packed with iron-oxide-coated sand. TPEs injecting three successive pulses in the order of nanoparticle, EDTA, nanoparticle permit nanoparticle deposition in the absence and the presence of EDTA to be compared. Random Sequential Adsorption (RSA) modelling of the nanoparticle breakthrough curves combining mass balance calculation allows the influence of EDTA to be quantified. TPE results demonstrate that the injected EDTA eluted the oxide coatings (favorable deposition sites) from the sand surface and the resulting decline in sites led to enhanced nanoparticle mobility in the subsequent pulse. Quantification results suggest that at the experimental time-scale and under the controlled conditions, elution of one deposition site requires injection of 2.4 × 10(11) EDTA molecules. In total, 75 gram EDTA needs to be injected to remove all the column sites.

  16. Oxidation of aqueous EDTA and associated organics and coprecipitation of inorganics by ambient iron-mediated aeration.

    PubMed

    Englehardt, James D; Meeroff, Daniel E; Echegoyen, Luis; Deng, Yang; Raymo, Françisco M; Shibata, Tomoyuki

    2007-01-01

    Cationic metal and radionuclide contaminants can be extracted from soils to groundwater with sequestering agents such as EDTA. However, EDTA must then be removed fromthe groundwater, by advanced oxidation or specialized biological treatment. In this work, aqueous individual metal-EDTA solutions were aerated with steel wool for 25 h, at ambient pH, temperature, and pressure. Removal of approximately 99% of EDTA (0.09-1.78 mM); glyoxylic acid (0.153 mM); chelated Cd2+ (0.94 and 0.0952 mM), Pb2+ (0.0502 mM), and Hg2+ (0.0419 mM); and free chromate and vanadate was shown. EDTA was oxidized to glyoxylic acid and formaldehyde, and metals/metalloids were coprecipitated together with iron oxyhydroxide floc. Free arsenite and arsenate were each removed at 99.97%. Free Sr2+, and chelated Ni2+ were removed at 92% and 63%, respectively. Similar removals were obtained from mixtures, including 99.996+/-0.004% removal of total arsenic (95% confidence). Traces of iminodiacetic acid, nitrilotriacetic acid, and ethylenediaminetriacetic acid were detected after 25 h. Results are consistent with first-order, solution-phase oxidation of EDTA and glyoxylic acid by ferryl ion and H202, respectively, with inhibition due to sludge accumulation, and equilibrium metal coprecipitation. This ambient process, to our knowledge previously unknown, agrees with recently reported findings and shows promise for remediation of metals, metalloids, and radionuclides in wastewater, soil, and sediment.

  17. Surface characterization of poly(L-lactic acid)-methoxy poly(ethylene glycol) diblock copolymers by static and dynamic contact angle measurements, FTIR, and ATR-FTIR.

    PubMed

    Mert, O; Doganci, E; Erbil, H Y; Demir, A S

    2008-02-01

    The surface composition and surface free energy properties of two types of amphiphilic and semicrystalline diblock copolymers consisting of poly(L-lactic acid) coupled to (methoxy poly(ethylene glycol) (PLLA-MePEG) having differing block lengths of PEG were investigated by using static and dynamic contact angle measurements, transmission Fourier infrared spectroscopy (FTIR), and attenuated total reflection spectroscopy (ATR-FTIR) and compared with results obtained from PLLA and MePEG homopolymers. The contact angle results were evaluated by using the van Oss-Good method (acid-base method), and it was determined that the Lewis base surface tension coefficient (gamma-) of the copolymers increased with an increase of the PEG molar content at the copolymer surface. This result is in good agreement with the transmission FTIR and ATR-FTIR results but not proportional to them, indicating that the surfaces of the copolymers are highly mobile and that the molecular rearrangement takes place upon contact with a polar liquid drop. The dynamic contact angle measurements showed that the strong acid-base interaction between the oxygen atoms in the copolymer backbone of the relatively more hydrophilic PEG segments with the Lewis acidic groups of the polar and hydrogen-bonding water molecules enabled the surface molecules to restructure (conformational change) at the contact area, so that the PEG segments moved upward, whereas the apolar methyl pendant groups of PLLA segments buried downward.

  18. Glucose-Responsive Hybrid Nanoassemblies in Aqueous Solutions: Ordered Phenylboronic Acid within Intermixed Poly(4-hydroxystyrene)-block-poly(ethylene oxide) Block Copolymer.

    PubMed

    Matuszewska, Alicja; Uchman, Mariusz; Adamczyk-Woźniak, Agnieszka; Sporzyński, Andrzej; Pispas, Stergios; Kováčik, Lubomír; Štěpánek, Miroslav

    2015-12-14

    Coassembly behavior of the double hydrophilic block copolymer poly(4-hydroxystyrene)-block-poly(ethylene oxide) (PHOS-PEO) with three amphiphilic phenylboronic acids (PBA) differing in hydrophobicity, 4-dodecyloxyphenylboronic acid (C12), 4-octyloxyphenylboronic acid (C8), and 4-isobutoxyphenylboronic acid (i-Bu) was studied in alkaline aqueous solutions and in mixtures of NaOHaq/THF by spin-echo (1)H NMR spectroscopy, dynamic and electrophoretic light scattering, and SAXS. The study reveals that only the coassembly of C12 with PHOS-PEO provides spherical nanoparticles with intermixed PHOS and PEO blocks, containing densely packed C12 micelles. NMR measurements have shown that spatial proximity of PHOS-PEO and C12 leads to the formation of ester bonds between -OH of PHOS block and hydroxyl groups of -B(OH)2. Due to the presence of PBA moieties, the release of compounds with 1,2- or 1,3-dihydroxy groups loaded in the coassembled PHOS-PEO/PBA nanoparticles by covalent binding to PBA can be triggered by addition of a surplus of glucose that bind to PBA competitively. The latter feature has been confirmed by fluorescence measurements using Alizarin Red as a model compound. Nanoparticles were proved to exhibit swelling in response to glucose as detected by light scattering.

  19. Acoustic and Ultrasonic Spectral Evolution in Pre- and Post-Damage Self-Healing Poly (Ethylene Co-Methacrylic Acid) Ionomer Samples

    NASA Astrophysics Data System (ADS)

    Buckley, Jonathan; Pestka, Kenneth, II; Kalista, Stephen

    We measured the pre- and post-damage resonant spectra of several self-healing ionomer samples composed of poly (ethylene co-methacrylic acid) (EMAA). The post-damage results indicate significant time-dependent variation in the acoustic and ultrasonic resonant spectral waveforms of these self-healing samples. These results are consistent with other recent experiments that demonstrate time evolution of resonant frequencies and associated quality factors within samples of post-damage EMAA ionomers. However, in our experiments it was found that, in some circumstances, the quality factors and associated resonant frequencies can exhibit time-dependent variation both before and after external damage. By quantifying time-dependent variations in the spectra of undamaged samples, including quality factor, resonant frequency and spectral waveform, we demonstrate a method to isolate changes in the resonant spectra that are present solely due to the post-damage healing behavior of these EMAA ionomers.

  20. Structural and cyclic volta metric investigations on BIPBVOX solid electrolyte synthesized by ethylene glycol-citric acid sol-gel route

    NASA Astrophysics Data System (ADS)

    Naqvi, Faria K.; Beg, Saba; Al-Areqi, Niyazi A. S.

    2016-05-01

    Samples of BIPBVOX.x (Bi2V1-xPbxO5.5-x/2) in the composition range 0.05 ≤ x ≤ 0.20 were prepared by ethylene glycol- citric acid sol-gel synthesis route. Structural investigations were carried out by X-ray diffraction, DTA. The highly conducting γ'- phase was effectively stabilized at room temperature for compositions with x ≥ 0.17. Cyclic voltammetric measurements showed reversible redox reactions of vanadium and irreversible redox reaction of Bi3+ in the BIPBVOX system during the first cathodic and anodic sweep. However, a higher stability against the reduction of Bi3+ to metallic bismuth was seen for x=0.20.

  1. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Xun, Luying; Bolton, Jr., Harvey

    2001-06-01

    Ethylenediaminetetraacetate (EDTA) and nitrilotriacetate (NTA) are synthetic chelating agents, which can form strong water-soluble complexes with radionuclides and metals and has been used to decontaminate and process nuclear materials. Synthetic chelating agents were co-disposed with radionuclides (e.g., 60Co, Pu) and heavy metals enhancing their transport in the subsurface. An understanding of EDTA biodegradation is essential to help mitigate enhanced radionuclide transport by EDTA. The objective of this research is to develop fundamental data on factors that govern the biodegradation of radionuclide-EDTA. These factors include the dominant EDTA aqueous species, the biodegradation of various metal-EDTA complexes, the uptake of various metal-EDTA complexes into the cell, the distribution and mobility of the radionuclide during and after EDTA biodegradation, and the enzymology and genetics of EDTA biodegradation.

  2. Competitive adsorption of Cu(II)-EDTA and Cd(II)-EDTA onto TiO{sub 2}

    SciTech Connect

    Yang, J.K.; Davis, A.P.

    1999-08-01

    Cu(II), EDTA, Cu(II)-EDTA, Cd(II)-EDTA, and Cu(II)/Cd(II) and Cu(II)-EDTA/Cd(II)-EDTA competitive adsorption onto TiO{sub 2} has been studied with variation of pH and concentration. For Cu(II) and EDTA, typical cationic and anionic types of adsorption are noted, respectively. Ligand-type adsorption is found for Cu(II)-EDTA and Cd(II)-EDTA under both single and competitive conditions. Surface complexation modeling considered inner-sphere complexation and the diffuse layer model employing MINTEQA2; surface complexes used include Ti-(OH{sub 2})O-Cu{sup +}, Ti-(OH)EDTAH{sub 2}{sup {minus}2}, Ti-(OH)EDTA-Cu{sup {minus}2}, and Ti-(OH)EDTA-Cd{sup {minus}2}. Experimental and model predictions suggest no competitive adsorption between Cu(II) and Cd(II) at 5 {times} 10{sup {minus}5} M. On the other hand, adsorption data and model predictions indicate that Cd(II)-EDTA adsorption is favored over that of Cu(II)-EDTA with some competition for adsorption sites. Cd(II)-EDTA Adsorption was only slightly affected by the presence of Cu(II)-EDTA; however, Cu(II)-EDTA adsorption was strongly influenced by the presence of Cd(II)-EDTA, especially as the molar ratio of Cd(II)-EDTA/Cu(II)-EDTA increased. A modified surface complexation constant for Cd(II)-EDTA is required to explain the competitive data, suggesting surface site heterogeneity.

  3. [Chronic ethylene glycol poisoning].

    PubMed

    Kaiser, W; Steinmauer, H G; Biesenbach, G; Janko, O; Zazgornik, J

    1993-04-30

    Over a six-week period a 60-year-old patient had several unexplained intoxication-like episodes. He finally had severe abdominal cramps with changes in the level of consciousness and oligoanuric renal failure (creatinine 4.7 mg/dl). The history, marked metabolic acidosis (pH 7.15, HCO3- 2.2 mmol/l, pCO2 6.6 mmHg) as well as raised anion residue (43 mmol/l) and the presence of oxalates in urine suggested poisoning by ethylene glycol contained in antifreeze liquid. Intensive haemodialysis adequately eliminated ethylene glycol and its toxic metabolites (glycol aldehyde, glycolic acid). Renal function returned within 10 days, although the concentrating power of the kidney remained impaired for several weeks because of interstitial nephritis. The intoxication had been caused by a defective heating-pipe system from which the antifreeze had leaked into the hot-water boiler (the patient had habitually prepared hot drinks by using water from the hot-water tap). Gas chromatography demonstrated an ethylene glycol concentration of 21 g per litre of water.

  4. Combined efficacy of nisin and pediocin with sodium lactate, citric acid, phytic acid, and potassium sorbate and EDTA in reducing the Listeria monocytogenes population of inoculated fresh-cut produce.

    PubMed

    Bari, M L; Ukuku, D O; Kawasaki, T; Inatsu, Y; Isshiki, K; Kawamoto, S

    2005-07-01

    The inability of chlorine to completely inactivate human bacterial pathogens on whole and fresh-cut produce suggests a need for other antimicrobial washing treatments. Nisin (50 microg/ml) and pediocin (100 AU/ml) individually or in combination with sodium lactate (2%), potassium sorbate (0.02%), phytic acid (0.02%), and citric acid (10 mM) were tested as possible sanitizer treatments for reducing the population of Listeria monocytogenes on cabbage, broccoli, and mung bean sprouts. Cabbage, broccoli, and mung bean sprouts were inoculated with a five-strain cocktail of L. monocytogenes at 4.61, 4.34, and 4.67 log CFU/g, respectively. Inoculated produce was left at room temperature (25 degrees C) for up to 4 h before antimicrobial treatment. Washing treatments were applied to inoculated produce for 1 min, and surviving bacterial populations were determined. When tested alone, all compounds resulted in 2.20- to 4.35-log reductions of L. monocytogenes on mung bean, cabbage, and broccoli, respectively. The combination treatments nisin-phytic acid and nisin-pediocin-phytic acid caused significant (P < 0.05) reductions of L. monocytogenes on cabbage and broccoli but not on mung bean sprouts. Pediocin treatment alone or in combination with any of the organic acid tested was more effective in reducing L. monocytogenes populations than the nisin treatment alone. Although none of the combination treatments completely eliminated the pathogen on the produce, the results suggest that some of the treatments evaluated in this study can be used to improve the microbial safety of fresh-cut cabbage, broccoli, and mung bean sprouts.

  5. Tuning of thermally induced sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid).

    PubMed

    Jin, Naixiong; Zhang, Hao; Jin, Shi; Dadmun, Mark D; Zhao, Bin

    2012-03-15

    We report in this article a method to tune the sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers that consist of two blocks exhibiting distinct lower critical solution temperatures (LCSTs) in water. A small amount of weak acid groups is statistically incorporated into the lower LCST block so that its LCST can be tuned by varying solution pH. Well-defined diblock copolymers, poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid) (PTEGMA-b-P(DEGEA-co-AA)), were prepared by reversible addition-fragmentation chain transfer polymerization and postpolymerization modification. PTEGMA and PDEGEA are thermosensitive water-soluble polymers with LCSTs of 58 and 9 °C, respectively, in water. A 25 wt % aqueous solution of PTEGMA-b-P(DEGEA-co-AA) with a molar ratio of DEGEA to AA units of 100:5.2 at pH = 3.24 underwent multiple phase transitions upon heating, from a clear, free-flowing liquid (<15 °C) to a clear, free-standing gel (15-46 °C) to a clear, free-flowing hot liquid (47-56 °C), and a cloudy mixture (≥57 °C). With the increase of pH, the sol-to-gel transition temperature (T(sol-gel)) shifted to higher values, while the gel-to-sol transition (T(gel-sol)) and the clouding temperature (T(clouding)) of the sample remained essentially the same. These transitions and the tunability of T(sol-gel) originated from the thermosensitive properties of two blocks of the diblock copolymer and the pH dependence of the LCST of P(DEGEA-co-AA), which were confirmed by dynamic light scattering and differential scanning calorimetry studies. Using the vial inversion test method, we mapped out the C-shaped sol-gel phase diagrams of the diblock copolymer in aqueous buffers in the moderate concentration range at three different pH values (3.24, 5.58, and 5.82, all measured at ~0 °C). While the upper temperature boundaries overlapped, the lower temperature boundary

  6. Participation of ethylene in gravitropism

    NASA Technical Reports Server (NTRS)

    Harrison, M.; Pickard, B. G.

    1984-01-01

    In shoots of many plants, of which tomato (Lycopersicon esculentum Mill.) is an example, ethylene production is substantially increased during gravitropism. As a first step toward elucidating the role of ethylene in gravitropism, detailed time courses of ethylene production in isolated hypocotyl segments and whole plants were measured for gravistimulated and upright tomato seedlings. In the first experiment, seedlings were set upright or laid horizontal and then, at 15 min intervals, sets of hypocotyls were excised and sealed into gas tight vials. A steady long term rise in ethylene production begins after 15 min gravistimulation. It is possible that this increase is a consequence of the accumulation of indoleacetic acid (IAA) in the lower tissue of the hypocotyle. In a second kind of experiment, whole seedlings were enclosed in sealed chambers and air samples were withdrawn at 5 min intervals. Stimulated seedlings produced more ethylene than controls during the first 5 min interval, but not appreciably more during the second. This suggests the possibility that the ethylene production induced during the first 5 min occurs immediately rather than after a lag, and thus much too soon to be controlled by redistribution of IAA.

  7. EDTA-insoluble, calcium-binding proteoglycan in bovine bone

    NASA Technical Reports Server (NTRS)

    Hashimoto, Y.; Lester, G. E.; Caterson, B.; Yamauchi, M.

    1995-01-01

    A calcium ion precipitable, trypsin-generated proteoglycan fragment has been isolated from the demineralized, EDTA-insoluble matrices of bone. The demineralized matrix was completely digested with trypsin, increasing concentrations of CaCl2 were added to the supernatant, and the resulting precipitates were analyzed. The amount of precipitate gradually increased with higher concentrations of calcium and was reversibly solubilized by EDTA. After molecular sieve and anion exchange chromatography, a proteoglycan-containing peak was obtained. Immunochemical analysis showed that this peak contained chondroitin 4-sulfate and possibly keratan sulfate. Amino acid analysis showed that this proteoglycan contained high amounts of aspartic acid/asparagine (Asx), serine (Ser), glutamic acid/glutamine (Glx), proline (Pro), and glycine (Gly); however, it contained little leucine (Leu) which suggests that it is not a member of the leucine-rich small proteoglycan family. In addition, significant amounts of phosphoserine (P-Ser) and hydroxyproline (Hyp) were identified in hydrolysates of this fraction. A single band (M(r) 59 kDa) was obtained on SDS-PAGE that stained with Stains-all but not with Coomassie Brilliant Blue R-250. If bone powder was trypsinized prior to demineralization, this proteoglycan-containing fraction was not liberated. Collectively, these results indicate that a proteoglycan occurs in the demineralized matrix that is precipitated with CaCl2 and is closely associated with both mineral and collagen matrices. Such a molecule might facilitate the structural network for the induction of mineralization in bone.

  8. Extractability of zinc, cadmium, and nickel in soils amended with EDTA

    SciTech Connect

    Li, Zhenbin; Shuman, L.M.

    1996-04-01

    Synthetic chelating agents are produced in large quantities for use in many industrial applications. Certain chelates, such as ethylenediaminetetraacetic acid (EDTA), are persistent in the environment. The presence of EDTA in soil may alter the mobility and transport of Zn, Cd, and Ni in soils because of the formation of water soluble chelates, thus increasing the potential for metal pollution of natural waters. Mobility of metals is related to their extractability. To investigate metal extractability affected by EDTA, Zn, Cd, and Ni were added to a portion of eight Georgia topsoil samples at rates of 75.9, 1.62, and 4.30 mg kg{sup -1}, respectively. Both natural and metal-amended soils were treated with Na{sub 2-}EDTA at rates of 0, 1.0, and 2.0 g kg{sup -1}. After 5 months of incubation, soil samples were extracted with Mehlich-1, DTPA (diethylenetriamine-pentaacetic acid) and 1 M Mg(NO{sub 3}){sub 2}, the latter of which extracts the exchangeable form of metals. Results showed that Zn and Ni in Mehlich-1 and DTPA extractions increased with increasing rates of EDTA. The increase for Cd was not as great as for Zn or Ni. Similar changes were found for the Mg(NO{sub 3}){sub 2} extraction. As a percentage of total metal concentration, the Mehlich-1 and DTPA extractable Zn was greater than Ni in the natural soils, and the order for the metal-amended soils was Cd > Zn > Ni. The results also suggested that EDTA significantly elevated the extractability of Zn and Ni in both natural and metal-amended soils. The order of mobility based on extractability was: Cd > Zn > Ni for metals added to soils, but when EDTA was present, added Ni was more extractable than Zn or Cd. 36 refs., 5 tabs.

  9. Enhanced biological phosphorus removal employing EDTA disodium

    SciTech Connect

    Bojinova, D.; Velkova, R.

    1996-12-31

    The biological phosphorus removal is a promising alternative to the conventional chemical technologies for processing of phosphate raw materials. The object of this study was the effect of EDTA disodium on the biotreatment of tunisian phosphorite with the strain of Aspergillus niger. The incubation was carried out in two nutritive mediums, with different phosphate content. The experimental results showed that the additives of EDTA disodium in the nutritive medium increased the rate of extraction of P{sub 2}O{sub 5} and shortened significantly the time for biological leaching. 5 refs., 3 figs., 2 tabs.

  10. Reduction of mercury from mackerel fillet using combined solution of cysteine, EDTA, and sodium chloride.

    PubMed

    Hajeb, P; Jinap, S

    2012-06-13

    An acidic solution containing mercury chelating agents to eliminate mercury in raw fish (mackerel) fillet was developed. The solution contained hydrochloric acid, sodium hydroxide, cysteine, EDTA, and NaCl. The optimum conditions for mercury reduction were achieved using response surface methodology (RSM) at cysteine concentration of 1.25%, EDTA of 275 mg/L, NaCl of 0.5%, pH of 3.75, and exposure time of 18 min. The optimized conditions produced a solution which can remove up to 91% mercury from raw fish fillet. Cysteine and EDTA were identified as potential chelating agents with the greatest potential for use. The solution can be employed in fish industries to reduce mercury in highly contaminated fish.

  11. Ethylene Gas in Storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene is a small volatile organic molecule that is produced by plants and many microbes. Potato tubers sense ethylene at concentrations of less than 1 ppm and respond to ethylene in ways that may be beneficial or detrimental for potato tuber storage. High concentrations of ethylene suppress sprou...

  12. [Effects of EDTA on the Reductive Dechlorination of 2,4-D by Pd/Fe].

    PubMed

    Zhou, Hong-yi; Nie, Ya-zhong; Chen, Yong; Lei, Shuang-jian

    2016-02-15

    In Pd/Fe system, zero-valent iron (ZVI) passivation layer is easily formed on the particle surface during the catalytic reductive dechlorination of chlorinated organics, hindering further dechlorination of target contaminants. In this paper, the passivation layer on the Pd/Fe particle surfaces could be eliminated by the chelation of disodium edetate (EDTA) with Fe2+, Fe3+, making the reductive dechlorination continue. The experiment investigated the effects of EDTA addition manner and dosage, pH, Pd loading and temperature on dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by Pd/Fe. The conclusions can be summarized as follows: (1) Phenoxyacetic acid (PA) generation ratio reached 90. 7% within 20 min with EDTA concentration of 25.0 mmol x L(-1) and flow rate of 20 mL x h(-1), while it was only 74.5% after 210 min in the system without EDTA. (2) The EDTA could chelate the Fe2+ and Fe3+ generated from the process of 2,4-D dechlorination by Pd/Fe, preventing or slowing down the formation of passivation layer, and accelerating the reduction efficiency. (3) The appropriate experimental parameters for 2,4-D removal were as follows: EDTA flow rate of 20 mL x h(-1), CEDTA of 25.0 mmol x L(-1), Pd loading of 0.050%, 200 r x min(-1), pH 4.2 and 30.0 degrees C. The removal percentage of 20.0 mg x L(-1) 2,4-D reached nearly up to 100% within 210 min under these conditions. (4) The intermediates of 2, 4-D catalytic dechlorination included 2-chlorophenoxvacetic acid (2-CPA) and trace 4-chloronhenoxyacetic acid (4-CPA), and the end product was PA.

  13. [Effects of EDTA on the Reductive Dechlorination of 2,4-D by Pd/Fe].

    PubMed

    Zhou, Hong-yi; Nie, Ya-zhong; Chen, Yong; Lei, Shuang-jian

    2016-02-15

    In Pd/Fe system, zero-valent iron (ZVI) passivation layer is easily formed on the particle surface during the catalytic reductive dechlorination of chlorinated organics, hindering further dechlorination of target contaminants. In this paper, the passivation layer on the Pd/Fe particle surfaces could be eliminated by the chelation of disodium edetate (EDTA) with Fe2+, Fe3+, making the reductive dechlorination continue. The experiment investigated the effects of EDTA addition manner and dosage, pH, Pd loading and temperature on dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by Pd/Fe. The conclusions can be summarized as follows: (1) Phenoxyacetic acid (PA) generation ratio reached 90. 7% within 20 min with EDTA concentration of 25.0 mmol x L(-1) and flow rate of 20 mL x h(-1), while it was only 74.5% after 210 min in the system without EDTA. (2) The EDTA could chelate the Fe2+ and Fe3+ generated from the process of 2,4-D dechlorination by Pd/Fe, preventing or slowing down the formation of passivation layer, and accelerating the reduction efficiency. (3) The appropriate experimental parameters for 2,4-D removal were as follows: EDTA flow rate of 20 mL x h(-1), CEDTA of 25.0 mmol x L(-1), Pd loading of 0.050%, 200 r x min(-1), pH 4.2 and 30.0 degrees C. The removal percentage of 20.0 mg x L(-1) 2,4-D reached nearly up to 100% within 210 min under these conditions. (4) The intermediates of 2, 4-D catalytic dechlorination included 2-chlorophenoxvacetic acid (2-CPA) and trace 4-chloronhenoxyacetic acid (4-CPA), and the end product was PA. PMID:27363149

  14. Anaerobic Biotransformation and Mobility of Pu and PuEDTA

    SciTech Connect

    Xun, Luying

    2005-06-01

    The objective of this report is to isolate anaerobic EDTA-degrading bacteria. Although our goal is to isolate anaerobic EDTA degraders, we initiated the experiments to include nitrilotriacetate (NTA), which is a structure homologue of EDTA. All the aerobic EDTA degraders can degrade NTA, but the isolated NTA degraders cannot degrade EDTA. Since NTA is a simpler structure homologue, it is likely that EDTA-degrading ability is evolved from NTA degradation. This hypothesis is further supported from our characterization of EDTA and NTA-degrading enzymes and genes (J. Bact. 179:1112-1116; and Appl. Environ. Microbiol. 67:688-695). The EDTA monooxygenase and NTA monooxygenase are highly homologous. EDTA monooxygenase can use both EDTA and NTA as substrates, but NTA monooxygenase can only use NTA as a substrate. Thus, we put our effort to isolate both NTA and EDTA degraders. In case, an anaerobic EDTA degrader is not immediately enriched, we will try to evolve the NTA degraders to use EDTA. Both aerobic and anaerobic enrichment cultures were set.

  15. Bacteria-Triggered Systemic Immunity in Barley Is Associated with WRKY and ETHYLENE RESPONSIVE FACTORs But Not with Salicylic Acid1[C][W

    PubMed Central

    Dey, Sanjukta; Wenig, Marion; Langen, Gregor; Sharma, Sapna; Kugler, Karl G.; Knappe, Claudia; Hause, Bettina; Bichlmeier, Marlies; Babaeizad, Valiollah; Imani, Jafargholi; Janzik, Ingar; Stempfl, Thomas; Hückelhoven, Ralph; Kogel, Karl-Heinz; Mayer, Klaus F.X.

    2014-01-01

    Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity. PMID:25332505

  16. Repression of the Arabidopsis thaliana jasmonic acid/ethylene-induced defense pathway by TGA-interacting glutaredoxins depends on their C-terminal ALWL motif.

    PubMed

    Zander, Mark; Chen, Shuxia; Imkampe, Julia; Thurow, Corinna; Gatz, Christiane

    2012-07-01

    Glutaredoxins are small heat-stable oxidoreductases that transfer electrons from glutathione (GSH) to oxidized cysteine residues, thereby contributing to protein integrity and regulation. In Arabidopsis thaliana, floral glutaredoxins ROXY1 and ROXY2 and pathogen-induced ROXY19/GRX480 interact with bZIP transcription factors of the TGACG (TGA) motif-binding family. ROXY1, ROXY2, and TGA factors PERIANTHIA, TGA9, and TGA10 play essential roles in floral development. In contrast, ectopically expressed ROXY19/GRX480 negatively regulates expression of jasmonic acid (JA)/ethylene (ET)-induced defense genes through an unknown mechanism that requires clade II transcription factors TGA2, TGA5, and/or TGA6. Here, we report that at least 17 of the 21 land plant-specific glutaredoxins encoded in the Arabidopsis genome interact with TGA2 in a yeast-two-hybrid system. To investigate their capacity to interfere with the expression of JA/ET-induced genes, we developed a transient expression system. Activation of the ORA59 (OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF-domain protein 59) promoter by transcription factor EIN3 (ETHYLENE INSENSITVE 3) was suppressed by co-expressed ROXY19/GRX480. Suppression depended on the L**LL motif in the C-terminus of ROXY19/GRX480. This putative protein interaction domain was recently described as being essential for the TGA/ROXY interaction. Ten of the 17 tested ROXY proteins suppressed ORA59 promoter activity, which correlated with the presence of the C-terminal ALWL motif, which is essential for ROXY1 function in flower development. ROXY19/GRX480-mediated repression depended on the GSH binding site, suggesting that redox modification of either TGA factors or as yet unknown target proteins is important for the suppression of ORA59 promoter activity.

  17. Tacticity-induced changes in the micellization and degradation properties of poly(lactic acid)-block-poly(ethylene glycol) copolymers.

    PubMed

    Agatemor, Christian; Shaver, Michael P

    2013-03-11

    Poly(lactic acid)-block-poly(ethylene glycol) copolymers (PLA-b-PEG) featuring varying tacticities (atactic, heterotactic, isotactic) in the PLA block were synthesized and investigated for their micellar stability, degradation, and thermal properties. Utilizing tin(II) bis(2-ethylhexanoate), aluminum salan, and aluminum salen catalysts, the copolymers were synthesized through the ring-opening polymerization of d-, l-, rac-, or a blend of l- and rac-lactide using monomethoxy-poly(ethylene glycol) as a macroinitiator. The critical micelle concentration, which reflects the micellar stability, was probed using a fluorescence spectroscopic method with pyrene as the probe. The copolymers were degraded in a methanolic solution of 1,5,7-triaza-bicyclo[4.4.0]dec-5-ene and the degradation was measured by (1)H NMR spectroscopic and gel permeation chromatographic analyses. Differential scanning calorimetry and thermogravimetric analysis provided information on the thermal properties of the copolymers. Atactic and heterotactic microstructures in the PLA block resulted in lower micellar stability, as well as faster degradation and shorter erosion time compared to polymers with high isotactic enchainment (Pm). By modification of the Pm, micellar stability, degradation, and erosion rates of the copolymers can be tuned to specific biomedical applications. Interestingly, while tin(II) bis(2-ethylhexanoate) and aluminum salan-catalyzed PLA-b-PEG copolymers exhibited similar micellization behavior, the aluminum salen-catalyzed PLA-b-PEG exhibited unique behavior at high micelle concentration in the presence of the pyrene probe. This unique behavior can be attributed to the disintegration of the micelles through the interactions of long isotactic stereoblock segments. PMID:23402292

  18. Genetic variation for lettuce seed thermoinhibition is associated with temperature-sensitive expression of abscisic Acid, gibberellin, and ethylene biosynthesis, metabolism, and response genes.

    PubMed

    Argyris, Jason; Dahal, Peetambar; Hayashi, Eiji; Still, David W; Bradford, Kent J

    2008-10-01

    Lettuce (Lactuca sativa 'Salinas') seeds fail to germinate when imbibed at temperatures above 25 degrees C to 30 degrees C (termed thermoinhibition). However, seeds of an accession of Lactuca serriola (UC96US23) do not exhibit thermoinhibition up to 37 degrees C in the light. Comparative genetics, physiology, and gene expression were analyzed in these genotypes to determine the mechanisms governing the regulation of seed germination by temperature. Germination of the two genotypes was differentially sensitive to abscisic acid (ABA) and gibberellin (GA) at elevated temperatures. Quantitative trait loci associated with these phenotypes colocated with a major quantitative trait locus (Htg6.1) from UC96US23 conferring germination thermotolerance. ABA contents were elevated in Salinas seeds that exhibited thermoinhibition, consistent with the ability of fluridone (an ABA biosynthesis inhibitor) to improve germination at high temperatures. Expression of many genes involved in ABA, GA, and ethylene biosynthesis, metabolism, and response was differentially affected by high temperature and light in the two genotypes. In general, ABA-related genes were more highly expressed when germination was inhibited, and GA- and ethylene-related genes were more highly expressed when germination was permitted. In particular, LsNCED4, a gene encoding an enzyme in the ABA biosynthetic pathway, was up-regulated by high temperature only in Salinas seeds and also colocated with Htg6.1. The temperature sensitivity of expression of LsNCED4 may determine the upper temperature limit for lettuce seed germination and may indirectly influence other regulatory pathways via interconnected effects of increased ABA biosynthesis.

  19. Dynamic NMR of Intramolecular Exchange Processes in EDTA Complexes of Sc[superscript 3+], Y[superscript 3+], and La[superscript 3+

    ERIC Educational Resources Information Center

    Ba, Yong; Han, Steven; Ni, Lily; Su, Tony; Garcia, Andres

    2006-01-01

    Dynamic NMR makes use of the effect of chemical exchanges on NMR spectra to study kinetics and thermodynamics. An advanced physical chemistry lab experiment was developed to study the intramolecular exchange processes of EDTA (the disodium salt of ethylenediaminetetraacetic acid) metal complexes. EDTA is an important chelating agent, used in…

  20. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Xun, Luying; Bolton, Harvey, Jr.

    2003-06-01

    This project is part of a major project (PI, Dr. Harvey Bolton, Jr. at PNNL) regarding plutonium mobility in the subsurface. Ethylenediaminetetraacetate (EDTA) is a common chelating agent that can increase the mobility of radionuclides and heavy metals in groundwater. Biodegradation of EDTA decreases the enhanced mobility. The overall objective is to understand how microbial degradation affects Plutonium-EDTA transport in the environment, and the specific objective of this component is to understand how microorganisms degrade EDTA. Over the past two years, significant progress has been made to the understanding on how EDTA is degraded by an EDTA-degrading bacterium BNC1. The characterization of EDTA and nitrilotriacetate (NTA) transport into BNC1 cells is summarized here. The uptake is the limiting step in EDTA and NTA degradation. The objectives of near-term research are described. We are making progress as projected in the proposal.

  1. Photocatalytic removal of selenite and selenate species: effect of EDTA and other process variables.

    PubMed

    Labaran, B A; Vohra, M S

    2014-01-01

    TiO2-assisted photocatalysis was employed for the removal of aqueous phase selenite and selenate species in conjunction with EDTA as a hole (h+) scavenger. Findings from the binary selenite/EDTA and selenate/EDTA systems showed high selenite and selenate removal at pH 4 and pH 6, with faster removal kinetics noted for the selenite species compared with the selenate species that showed a gradual change over the reaction course. The noted removal of selenite and selenate was attributed to their reduction by the conduction band electrons (e-). The effect of pH studies indicated high selenite, selenate, and EDTA removal in the acidic pH range, with the following specific trend: pH 4 > pH 6 > pH 12. Different from the EDTA studies, the use of thiocyanate alone did not initiate reduction of selenium oxyanions, and hence, its role as a hole scavenger in the present systems was not evident. However, the addition of EDTA to respective selenite/selenate/thiocyanate system at pH 4 did yield near complete removal of selenite and selenate species. The marginal role of thiocyanate as a hole scavenger was attributed to its negligible adsorption onto TiO2 surface. Furthermore, at pH 4 and within 3 h reaction time, enhanced selenate removal was noted with an increase in its initial concentration from 20 to 100 ppm, with near complete selenate removal noted for both cases. In general, findings from the present work indicate that both selenite and selenate can be successfully removed from the aqueous phase employing the TiO2-mediated photocatalysis and h(+)-scavenging agent EDTA.

  2. Heavy metal extraction from an artificially contaminated sandy soil under EDDS deficiency: significance of humic acid and chelant mixture.

    PubMed

    Yip, Theo C M; Yan, Dickson Y S; Yui, Matthew M T; Tsang, Daniel C W; Lo, Irene M C

    2010-06-01

    Biodegradable EDDS ([S,S]-ethylenediaminedisuccinic acid) has been suggested for enhancing heavy metal extraction from contaminated soils. Recent studies showed that Zn and Pb are less effectively extracted due to metal exchange and re-adsorption onto the soil surfaces, especially for EDDS-deficiency conditions. This study therefore investigated the influence of dissolved organic matter and the co-presence of EDTA (ethylene-diamine-tetraacetic acid) on metal extraction from an artificially contaminated sandy soil under deficient amount of chelants in batch kinetics experiments. The addition of 10 and 20mgL(-1) of humic acid as dissolved organic matter (DOC) suppressed metal extraction by EDDS, probably resulting from the competition of adsorbed humic acid for heavy metals and adsorption of metal-humate complexes onto the soil surfaces. The effects were most significant for Pb because of greater extent of metal exchange of PbEDDS and high affinity towards organic matter. Thus, one should be cautious when there is a high content of organic matter in soils or groundwater. On the other hand, compared to individual additions of EDDS or EDTA, the equimolar EDDS and EDTA mixture exhibited significantly higher Pb extraction without notable Pb re-adsorption. The synergistic performance of the EDDS and EDTA mixture probably resulted from the change of chemical speciation and thus less competition among Cu, Zn and Pb for each chelant. These findings suggest further investigation into an optimum chemistry of the chelant mixture taking into account the effectiveness and associated environmental impact.

  3. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Bolton, H., Jr.; Rai, D.; Xun, L.

    2004-03-17

    The contamination of many DOE sites by Pu presents a long-term problem because of its long half-life (240,000 yrs) and the low drinking water standard (<10{sup -12} M). EDTA was co-disposed with radionuclides (e.g., Pu, {sup 60}Co), formed strong complexes, and enhanced radionuclide transport at several DOE sites. Biodegradation of EDTA should decrease Pu mobility. One objective of this project was to determine the biodegradation of EDTA in the presence of PuEDTA complexes. The aqueous system investigated at pH 7 (10{sup -4} M EDTA and 10{sup -6} M Pu) contained predominantly Pu(OH){sub 2}EDTA{sup 2-}. The EDTA was degraded at a faster rate in the presence of Pu. As the total concentration of both EDTA and PuEDTA decreased (i.e., 10{sup -5} M EDTA and 10{sup -7} M PuEDTA), the presence of Pu decreased the biodegradation rate of the EDTA. It is currently unclear why the concentration of Pu directly affects the increase/decrease in rate of EDTA biodegradation. The soluble Pu concentration decreased, in agreement with thermodynamic predictions, as the EDTA was biodegraded, indicating that biodegradation of EDTA will decrease Pu mobility when the Pu is initially present as Pu(IV)EDTA. A second objective was to investigate how the presence of competing metals, commonly encountered in geologic media, will influence the speciation and biodegradation of Pu(IV)-EDTA. Studies on the solubilities of Fe(OH){sub 3}(s) and of Fe(OH){sub 3}(s) plus PuO{sub 2}(am) in the presence of EDTA and as a function of pH showed that Fe(III) out competes the Pu(IV) for the EDTA complex, thereby showing that Pu(IV) will not form stable complexes with EDTA for enhanced transport of Pu in Fe(III) dominated subsurface systems. A third objective is to investigate the genes and enzymes involved in EDTA biodegradation. BNC1 can use EDTA and another synthetic chelating agent nitrilotriacetate (NTA) as sole carbon and nitrogen sources. The same catabolic enzymes are responsible for both EDTA and NTA

  4. Differential Effects of Elevated Ozone on Two Hybrid Aspen Genotypes Predisposed to Chronic Ozone Fumigation. Role of Ethylene and Salicylic Acid1

    PubMed Central

    Vahala, Jorma; Keinänen, Markku; Schützendübel, Andres; Polle, Andrea; Kangasjärvi, Jaakko

    2003-01-01

    The role of ethylene (ET) signaling in the responses of two hybrid aspen (Populus tremula L. × P. tremuloides Michx.) clones to chronic ozone (O3; 75 nL L−1) was investigated. The hormonal responses differed between the clones; the O3-sensitive clone 51 had higher ET evolution than the tolerant clone 200 during the exposure, whereas the free salicylic acid concentration in clone 200 was higher than in clone 51. The cellular redox status, measured as glutathione redox balance, did not differ between the clones suggesting that the O3 lesions were not a result of deficient antioxidative capacity. The buildup of salicylic acid during chronic O3 exposure might have prevented the up-regulation of ET biosynthesis in clone 200. Blocking of ET perception with 1-methylcyclopropene protected both clones from the decrease in net photosynthesis during chronic exposure to O3. After a pretreatment with low O3 for 9 d, an acute 1.5-fold O3 elevation caused necrosis in the O3-sensitive clone 51, which increased substantially when ET perception was blocked. The results suggest that in hybrid aspen, ET signaling had a dual role depending on the severity of the stress. ET accelerated leaf senescence under low O3, but under acute O3 elevation, ET signaling seemed to be required for protection from necrotic cell death. PMID:12746525

  5. In vivo toxicity and immunogenicity of wheat germ agglutinin conjugated poly(ethylene glycol)-poly(lactic acid) nanoparticles for intranasal delivery to the brain

    SciTech Connect

    Liu Qingfeng; Shao Xiayan; Chen Jie; Shen Yehong; Feng Chengcheng; Gao Xiaoling; Zhao Yue; Li Jingwei; Zhang Qizhi Jiang, Xinguo

    2011-02-15

    Biodegradable polymer-based nanoparticles have been widely studied to deliver therapeutic agents to the brain after intranasal administration. However, knowledge as to the side effects of nanoparticle delivery system to the brain is limited. The aim of this study was to investigate the in vivo toxicity and immunogenicity of wheat germ agglutinin (WGA) conjugated poly(ethylene glycol)-poly(lactic acid) nanoparticles (WGA-NP) after intranasal instillation. Sprague-Dawley rats were intranasally given WGA-NP for 7 continuous days. Amino acid neurotransmitters, lactate dehydrogenase (LDH) activity, reduced glutathione (GSH), acetylcholine, acetylcholinesterase activity, tumor necrosis factor {alpha} (TNF-{alpha}) and interleukin-8 (IL-8) in rat olfactory bulb (OB) and brain were measured to estimate the in vivo toxicity of WGA-NP. Balb/C mice were intranasally immunized by WGA-NP and then WGA-specific antibodies in serum and nasal wash were detected by indirect ELISA. WGA-NP showed slight toxicity to brain tissue, as evidenced by increased glutamate level in rat brain and enhanced LDH activity in rat OB. No significant changes in acetylcholine level, acetylcholinesterase activity, GSH level, TNF-{alpha} level and IL-8 level were observed in rat OB and brain for the WGA-NP group. WGA-specific antibodies in mice serum and nasal wash were not increased after two intranasal immunizations of WGA-NP. These results demonstrate that WGA-NP is a safe carrier system for intranasal delivery of therapeutic agents to the brain.

  6. Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Nho, Young Chang; Mook Lim, Youn; Moo Lee, Young

    2004-09-01

    pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mm×3 mm×2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract.

  7. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  8. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  9. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  10. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  11. 21 CFR 73.2120 - Disodium EDTA-copper.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Disodium EDTA-copper. 73.2120 Section 73.2120 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2120 Disodium EDTA-copper. (a) Identity. The color additive disodium EDTA-copper is disodium ] (4-)-N,N′,O,O′,O N,O N′] cuprate (2-)....

  12. Degradation of EDTA and novel complexing agents in pulp and paper mill process and waste waters by Fenton's reagent.

    PubMed

    Pirkanniemi, Kari; Metsärinne, Sirpa; Sillanpää, Mika

    2007-08-17

    Fenton's process was used in oxidative degradation of ethylediaminetetraacetic acid (EDTA) and novel complexing agents, namely BCA5 and BCA6, in distilled water and spiked samples of integrated pulp and paper mill waste water and ECF-pulp bleaching effluent. In waste water, over 90% of EDTA was degraded within 3 min when temperature was 60 degrees C, pH 4, and molecular ratio of H2O2:Fe2+:EDTA was 70:2:1 (0.26 mM EDTA) or higher. In spiked ECF bleaching effluent up to 42% of EDTA was degraded in similar reaction conditions, still higher than published results indicate biological waste water treatment of pulp and paper mill waste water being capable of. In pH 3, EDTA proved readily degradable by Fenton's process in otherwise similar conditions. According to these results, Fenton's process could be used as a pre-treatment method for EDTA-containing bleaching effluents prior to the biological waste water treatment. In addition, BCA5 and BCA6 proved their superiority in terms of degradability also by Fenton's process in both pH 3 and 4.

  13. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus.

    PubMed

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1-2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1-2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  14. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus

    PubMed Central

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1–2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1–2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  15. Denaturation of metalloproteins with EDTA to facilitate enzymatic digestion and mass fingerprinting.

    PubMed

    Janecki, Dariusz J; Reilly, James P

    2005-01-01

    Metal ions bound to a protein often stabilize tertiary and/or quaternary structure. Consequently, the digestion of metalloproteins that precedes analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is frequently incomplete. It is demonstrated that ethylenediaminetetraacetic acid (EDTA) successfully destabilizes metalloprotein structure and thereby facilitates tryptic digestion and protein identification.

  16. Denaturation of metalloproteins with EDTA to facilitate enzymatic digestion and mass fingerprinting.

    PubMed

    Janecki, Dariusz J; Reilly, James P

    2005-01-01

    Metal ions bound to a protein often stabilize tertiary and/or quaternary structure. Consequently, the digestion of metalloproteins that precedes analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is frequently incomplete. It is demonstrated that ethylenediaminetetraacetic acid (EDTA) successfully destabilizes metalloprotein structure and thereby facilitates tryptic digestion and protein identification. PMID:15834845

  17. Ethylene Glycol Metabolism by Pseudomonas putida

    PubMed Central

    Mückschel, Björn; Simon, Oliver; Klebensberger, Janosch; Graf, Nadja; Rosche, Bettina; Altenbuchner, Josef; Pfannstiel, Jens; Huber, Armin

    2012-01-01

    In this study, we investigated the metabolism of ethylene glycol in the Pseudomonas putida strains KT2440 and JM37 by employing growth and bioconversion experiments, directed mutagenesis, and proteome analysis. We found that strain JM37 grew rapidly with ethylene glycol as a sole source of carbon and energy, while strain KT2440 did not grow within 2 days of incubation under the same conditions. However, bioconversion experiments revealed metabolism of ethylene glycol by both strains, with the temporal accumulation of glycolic acid and glyoxylic acid for strain KT2440. This accumulation was further increased by targeted mutagenesis. The key enzymes and specific differences between the two strains were identified by comparative proteomics. In P. putida JM37, tartronate semialdehyde synthase (Gcl), malate synthase (GlcB), and isocitrate lyase (AceA) were found to be induced in the presence of ethylene glycol or glyoxylic acid. Under the same conditions, strain KT2440 showed induction of AceA only. Despite this difference, the two strains were found to use similar periplasmic dehydrogenases for the initial oxidation step of ethylene glycol, namely, the two redundant pyrroloquinoline quinone (PQQ)-dependent enzymes PedE and PedH. From these results we constructed a new pathway for the metabolism of ethylene glycol in P. putida. Furthermore, we conclude that Pseudomonas putida might serve as a useful platform from which to establish a whole-cell biocatalyst for the production of glyoxylic acid from ethylene glycol. PMID:23023748

  18. Ethylene glycol metabolism by Pseudomonas putida.

    PubMed

    Mückschel, Björn; Simon, Oliver; Klebensberger, Janosch; Graf, Nadja; Rosche, Bettina; Altenbuchner, Josef; Pfannstiel, Jens; Huber, Armin; Hauer, Bernhard

    2012-12-01

    In this study, we investigated the metabolism of ethylene glycol in the Pseudomonas putida strains KT2440 and JM37 by employing growth and bioconversion experiments, directed mutagenesis, and proteome analysis. We found that strain JM37 grew rapidly with ethylene glycol as a sole source of carbon and energy, while strain KT2440 did not grow within 2 days of incubation under the same conditions. However, bioconversion experiments revealed metabolism of ethylene glycol by both strains, with the temporal accumulation of glycolic acid and glyoxylic acid for strain KT2440. This accumulation was further increased by targeted mutagenesis. The key enzymes and specific differences between the two strains were identified by comparative proteomics. In P. putida JM37, tartronate semialdehyde synthase (Gcl), malate synthase (GlcB), and isocitrate lyase (AceA) were found to be induced in the presence of ethylene glycol or glyoxylic acid. Under the same conditions, strain KT2440 showed induction of AceA only. Despite this difference, the two strains were found to use similar periplasmic dehydrogenases for the initial oxidation step of ethylene glycol, namely, the two redundant pyrroloquinoline quinone (PQQ)-dependent enzymes PedE and PedH. From these results we constructed a new pathway for the metabolism of ethylene glycol in P. putida. Furthermore, we conclude that Pseudomonas putida might serve as a useful platform from which to establish a whole-cell biocatalyst for the production of glyoxylic acid from ethylene glycol.

  19. The improved phytoextraction of lead (Pb) and the growth of maize (Zeamays L.): the role of plant growth regulators (GA3 and IAA) and EDTA alone and in combinations.

    PubMed

    Hadi, Fazal; Bano, Asghari; Fuller, Michael P

    2010-06-01

    This investigation was made to examine the role of gibberellic acid (GA(3)), indole-3-acetic acid (IAA) and EDTA in improving phytoextraction of the Pb and plant growth on Pb added soil. GA(3), IAA and EDTA were applied separately and in combinations. GA(3) and IAA were applied as foliar spray and seed soaking. EDTA was applied in single and split doses. Analysis of the Pb in different parts of plant was carried out using atomic absorption/flame spectrophotometer. EDTA significantly reduced the plant growth and dry biomass, whereas GA(3) and IAA foliar spray increased it significantly when compared with control (only Pb added soil). In combined treatments of EDTA+GA(3) and EDTA+IAA, the growth and biomass was restored, which shows that GA(3) and IAA did compensate the negative effect of EDTA on plant growth. The separate treatments of EDTA, GA(3) and IAA increased the Pb uptake and translocation significantly moreover in combine treatments, synergistic effect was found and remarkable increase in Pb uptake and translocation into shoot was observed. EDTA increased the Pb uptake but declined the biomass; subsequently the total Pb accumulation was decreased in plant. The maximum total Pb was found in combined treatment of EDTA+GA(3). These findings suggest more investigation to find a combination of GA(3) with a very low concentration of EDTA, as in high concentration it causes soil and ground water pollution.

  20. Effects of Ethylene on Auxin Transport 1

    PubMed Central

    Morgan, Page W.; Gausman, Harold W.

    1966-01-01

    The effect of ethylene on the uptake, distribution and polar transport of C14 from indole-3-acetic acid-2-C14 and naphthalene acetic acid-1-C14 in tissue sections was studied. Test species were cotton (Gossypium hirsutum, L.) and cowpea (Vigna sinensis, Endl.). Generally, incubation of tissue or intact plants with ethylene reduced the degree of polar auxin transport. Ethylene inhibited the movement of both auxins in stem tissue and IAA in petiole tissue of cotton. The effect of ethylene on auxin movement in cow-peas was more complex. Ethylene apparently inhibited transport in younger petiole and stem tissue, but stimulated the process to a small but significant degree in basal petiole segments. Ethylene, in some experiments, reduced C14 (auxin) uptake. This reduction was consistently smaller than the inhibition of transport. Effects upon transport were observed when uptake was not different. Differences in uptake declined as the period of incubation with auxin was lengthened, but transport was inhibited for up to 23 hours. It is proposed that ethylene may, through its effect on transport, cause localized shortages and surpluses of auxin which in turn contribute to symptoms now associated with the response of sensitive species to ethylene. PMID:16656230

  1. Pd/RGO modified carbon felt cathode for electro-Fenton removing of EDTA-Ni.

    PubMed

    Zhang, Zhen; Zhang, Junya; Ye, Xiaokun; Hu, Yongyou; Chen, Yuancai

    2016-01-01

    Ethylenediaminetetraacetic acid (EDTA) forms stable complexes with toxic metals such as nickel due to its strong chelation. The electro-Fenton (EF) process using a cathode made from palladium (Pd), reduced graphene oxide (RGO) and carbon felt, fed with air, exhibited high activities and stability for the removal of 10 mg L(-1) EDTA-Ni solution. Pd/RGO catalyst was prepared by one-pot synthesis; the scanning electron microscopy and X-ray diffraction analysis indicated nanoparticles and RGO were well distributed on carbon felt, forming three dimensional architecture with both large macropores and a mesoporous structure. The cyclic voltammetric results showed that the presence of RGO in Pd/RGO/carbon felt significantly increased the current response of two-electron reduction of O2 (0.45 V). The key factors influencing the removal efficiency of EDTA-Ni, such as pH, current and Fe(2+) concentration, were investigated. Under the optimum conditions, the removal efficiency of EDTA-Ni reached 83.8% after 100 min EF treatment. Mechanism analysis indicated that the introduction of RGO in Pd/RGO/carbon felt significantly enhanced the electrocatalytic activities by inducing •OH in the EF process; direct H2O2 oxidation still accounted for a large amount of EDTA-Ni removal efficiency. PMID:27508368

  2. Total Degradation of EDTA by Mixed Cultures and a Bacterial Isolate

    PubMed Central

    Nörtemann, Bernd

    1992-01-01

    A bacterial mixed culture, which was obtained from sewage by a special enrichment procedure, utilized EDTA as the sole source of carbon and nitrogen for growth. High concentrations of mineral salts, particularly CaCl2, or the use of a mineral base without nitrogen protected the cells from inactivation after transfer into fresh medium containing 200-mg/liter (0.67 mM) EDTA. The chemical speciation did not influence the biodegradability of EDTA. However, when resting cells of the mixed culture were incubated with EDTA in the presence of an equivalent molar amount of FeCl3, the reaction came to a halt before the complete consumption of the substrate. A gram-negative isolate from the mixed population, BNC1, also metabolized EDTA in monoculture. Growth of the pure culture was promoted by biotin or folic acid but was always accompanied by the accumulation of unidentified metabolites and was slow (μmax, 0.024 h-1) compared with that of the original community (μmax, 0.036 h-1). Images PMID:16348653

  3. The influence of EDTA application on the interactions of cadmium, zinc, and lead and their uptake of rainbow pink (Dianthus chinensis).

    PubMed

    Lai, Hung-Yu; Chen, Zueng-Sang

    2006-10-11

    Soil used in this study was artificially contaminated with Cd, Zn, Pb, or applied in combinations (Cd-Zn, Cd-Pb, Zn-Pb, or Cd-Zn-Pb) to study the interactions of metals in soil contaminated with multiple metals. After planting rainbow pink (Dianthus chinensis) in these soils for 21 days, three different concentrations of ethylenedinitrilotetraacetic acid (EDTA) solutions were added to study the effect of applying EDTA on the interactions among these metals. The concentrations of Cd, Zn, and Pb in the soil solutions of different metals-treated soils increased significantly after applying 5 mmol EDTA kg(-1) soil (p<0.05). The potential of groundwater contamination will increase after applying EDTA and it is not recommended to be in situ used or have to use very carefully. The existence of Pb in the Cd-contaminated soil enhanced the uptake of Cd in rainbow pink in the treatments of control and 2 mmol EDTA kg(-1) soil. Cadmium inhibited the concentration of Zn without applying EDTA. However, whether the application of EDTA or not and the applied EDTA concentration had the greatest effect on the uptake of Pb when compared to Cd and Zn. After applying 5 mmol EDTA kg(-1) soil, Cd or Zn in the Pb-contaminated soil inhibited the uptake of Pb in rainbow pink, but there were no effect in other treatments.

  4. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    PubMed

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation. PMID:27652705

  5. 1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

    PubMed

    Macedo, Helena Suleiman de; Messias, Danielle Cristine Furtado; Rached-Júnior, Fuad Jacob; Oliveira, Ligia Teixeira de; Silva-Sousa, Yara Teresinha Correa; Raucci-Neto, Walter

    2016-01-01

    Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation.

  6. Adsorption of Pb(II), EDTA, and Pb(II)-EDTA onto TiO{sub 2}

    SciTech Connect

    Vohra, M.S.; Davis, A.P.

    1998-02-01

    The adsorption of aqueous Pb(II), EDTA, and Pb(II)-EDTA complexes onto TiO{sub 2} were studied at both stoichiometric and non-stoichiometric Pb(II)/EDTA concentrations. For Pb(II)-TiO{sub 2} and ECTA-TiO{sub 2}, a typical cationic and anionic-type of adsorption was noted, respectively. For 10{sup {minus}3} and 10{sup {minus}4} M Pb(II)-EDTA systems, near-equal adsorption of Pb(II) and EDTA indicated that the complex adsorbs as a single species. Also, a ligand-type Pb(II)-EDTA adsorption, i.e., decreasing adsorption with an increase in the pH, was noted. Systems with EDTA greater than Pb(II) showed near-zero lead removal; competitive adsorption of EDTA and Pb(II)-EDTA onto TiO{sub 2} was suggested to cause this effect. For Pb(II) concentrations (5 {times} 10{sup {minus}4} and 10{sup {minus}3} M) higher than EDTA (10{sup {minus}4} M), significantly higher EDTA adsorption at high pH as compared to individual 10{sup {minus}4} EDTA and 10{sup {minus}4} M Pb(II)-EDTA systems was noted. Adsorption modeling was completed employing the geochemical speciation model MINTEQA2 employing the diffuse layer model. Inner-sphere complexation was considered to occur between Pb(II), EDTA, Pb(II)-EDTA, and the TiO{sub 2} surface sites. Surface complexes used in the modeling included Ti-O-Pb{sup +}, Ti-EDTAH{sup 2{minus}}, Ti-EDTA-Pb{sup {minus}}, and Ti-O-Pb-EDTA{sup 3{minus}}. The cationic-type complexation, Ti-O-Pb-EDTA{sup 3{minus}}, was postulated to explain and model the anomalous EDTA adsorption as noted for Pb(II) > EDTA studies. Results from the present study show that the adsorption behavior in aqueous metal/EDTA systems will change with any variation in the contaminant concentration ratios.

  7. Biotransformation of PuEDTA: Implications to Pu Immobilization

    SciTech Connect

    Bolton, Harvey, Jr.

    2006-06-01

    This project integrates three distinct goals to develop a fundamental understanding of the potential fate and disposition of plutonium in sediments that are co-contaminated with EDTA. The three objectives are: (1) Develop thermodynamic data for Pu-EDTA species and determine the dominant mobile form of Pu under anaerobic conditions. (2) Elucidate the mechanism and rates of Pu(IV) and Pu(IV)-EDTA reduction by metal-reducing bacteria and determine where the Pu is located (in solution, biosorbed, bioaccumulated). (3) Enrich and isolate anaerobic EDTA-degrading microorganisms to investigate the anaerobic biodegradation of Pu-EDTA.

  8. Synergetic effects of DA-6/GA₃ with EDTA on plant growth, extraction and detoxification of Cd by Lolium perenne.

    PubMed

    He, Shanying; Wu, Qiuling; He, Zhenli

    2014-12-01

    Research is needed to improve efficiency of phytoextraction of heavy metals from contaminated soils. A pot experiment was carried out to study the effects of plant growth regulators (PGRs) (diethyl aminoethyl hexanoate (C18H33NO8, DA-6) and gibberellic acid 3 (C19H22O6, GA3)) and/or EDTA on Cd extraction, subcellular distribution and chemical forms in Lolium perenne. The addition of EDTA or PGRs significantly enhanced Cd extraction efficiency (P<0.05), with the decreasing order of: 1 μM DA-6>10 μM DA-6>10 μM GA3>2.5 mmol kg(-1) EDTA>other treatments of PGR alone. PGRs+EDTA resulted in a further increase in Cd extraction efficiency, with EDTA+1 μM DA-6 being the most efficient. At the subcellular level, about 44-57% of Cd was soluble fraction, 18-44% in cell walls, and 12-25% in cellular organelles fraction. Chemical speciation analysis showed that 40-54% of Cd was NaCl extractable, 7-23% HAc extractable, followed by other fractions. EDTA increased the proportions of Cd in soluble and cellular organelles fraction, as well as the metal migration in shoot; therefore, the toxicity to plant increased and plant growth was inhibited. Conversely, PGRs fixed more Cd in cell walls and reduced Cd migration in shoot; thus, metal toxicity was reduced. In addition, PGRs promoted plant biomass growth significantly (P<0.05), with 1 μM DA-6 being the most effective. A combination of DA-6/GA3 with EDTA can alleviate the adverse effect of EDTA on plant growth, and the treatment of EDTA+1 μM DA-6 appears to be optimal for improving the remediation efficiency of L. perenne for Cd contaminated soil. PMID:24999226

  9. Synergetic effects of DA-6/GA₃ with EDTA on plant growth, extraction and detoxification of Cd by Lolium perenne.

    PubMed

    He, Shanying; Wu, Qiuling; He, Zhenli

    2014-12-01

    Research is needed to improve efficiency of phytoextraction of heavy metals from contaminated soils. A pot experiment was carried out to study the effects of plant growth regulators (PGRs) (diethyl aminoethyl hexanoate (C18H33NO8, DA-6) and gibberellic acid 3 (C19H22O6, GA3)) and/or EDTA on Cd extraction, subcellular distribution and chemical forms in Lolium perenne. The addition of EDTA or PGRs significantly enhanced Cd extraction efficiency (P<0.05), with the decreasing order of: 1 μM DA-6>10 μM DA-6>10 μM GA3>2.5 mmol kg(-1) EDTA>other treatments of PGR alone. PGRs+EDTA resulted in a further increase in Cd extraction efficiency, with EDTA+1 μM DA-6 being the most efficient. At the subcellular level, about 44-57% of Cd was soluble fraction, 18-44% in cell walls, and 12-25% in cellular organelles fraction. Chemical speciation analysis showed that 40-54% of Cd was NaCl extractable, 7-23% HAc extractable, followed by other fractions. EDTA increased the proportions of Cd in soluble and cellular organelles fraction, as well as the metal migration in shoot; therefore, the toxicity to plant increased and plant growth was inhibited. Conversely, PGRs fixed more Cd in cell walls and reduced Cd migration in shoot; thus, metal toxicity was reduced. In addition, PGRs promoted plant biomass growth significantly (P<0.05), with 1 μM DA-6 being the most effective. A combination of DA-6/GA3 with EDTA can alleviate the adverse effect of EDTA on plant growth, and the treatment of EDTA+1 μM DA-6 appears to be optimal for improving the remediation efficiency of L. perenne for Cd contaminated soil.

  10. Magnetic nanocarriers of doxorubicin coated with poly(ethylene glycol) and folic acid: relation between coating structure, surface properties, colloidal stability, and cancer cell targeting.

    PubMed

    Kaaki, Karine; Hervé-Aubert, Katel; Chiper, Manuela; Shkilnyy, Andriy; Soucé, Martin; Benoit, Roland; Paillard, Archibald; Dubois, Pierre; Saboungi, Marie-Louise; Chourpa, Igor

    2012-01-17

    We report the efficient one-step synthesis and detailed physicochemical evaluation of novel biocompatible nanosystems useful for cancer therapeutics and diagnostics (theranostics). These systems are the superparamagnetic iron oxide nanoparticles (SPIONs) carrying the anticancer drug doxorubicin and coated with the covalently bonded biocompatible polymer poly(ethylene glycol) (PEG), native and modified with the biological cancer targeting ligand folic acid (PEG-FA). These multifunctional nanoparticles (SPION-DOX-PEG-FA) are designed to rationally combine multilevel mechanisms of cancer cell targeting (magnetic and biological), bimodal cancer cell imaging (by means of MRI and fluorescence), and bimodal cancer treatment (by targeted drug delivery and by hyperthermia effect). Nevertheless, for these concepts to work together, the choice of ingredients and particle structure are critically important. Therefore, in the present work, a detailed physicochemical characterization of the organic coating of the hybrid nanoparticles is performed by several surface-specific instrumental methods, including surface-enhanced Raman scattering (SERS) spectroscopy, X-ray photoelectron spectrometry (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). We demonstrate that the anticancer drug doxorubicin is attached to the iron oxide surface and buried under the polymer layers, while folic acid is located on the extreme surface of the organic coating. Interestingly, the moderate presence of folic acid on the particle surface does not increase the particle surface potential, while it is sufficient to increase the particle uptake by MCF-7 cancer cells. All of these original results contribute to the better understanding of the structure-activity relationship for hybrid biocompatible nanosystems and are encouraging for the applications in cancer theranostics.

  11. Trans and positional ethylenic bonds in two dominant isomers of eicosapentaenoic acid from the freshwater sponge Baicalospongia bacillifera.

    PubMed

    Imbs, Andrey B; Rodkina, Svetlana A

    2005-09-01

    Reinvestigation of the current FA composition of the regional freshwater sponge Baicalospongia bacillifera showed that the main measured isomer of EPA (14% of the total FA now detected) is, in fact, an unusual 5Z,8Z,11Z,14Z,18E-EPA. Two other isomers of this acid also present were identified as a novel 5Z,8Z,11Z,15Z,18E-EPA and the common methylene-interrupted 5Z,8Z,11Z,14Z,17Z-EPA (usually written simply as EPA). Isolation of these acids as their methyl ester derivatives was accomplished with the use of a combination of silver-ion column chromatography and HPLC. The structure of the two new compounds was deduced from GC-MS and detailed NMR data. Partial hydrazine reduction of all three isolated EPA esters followed by separation of cis/trans isomers of the resulting monoenoic acids and GC-MS analysis of their dimethyl disulfide adducts were used for determination of the configuration and position of the double bonds. We may assume that the sponge B. bacillifera cannot receive these unusual EPA isomers directly from food sources (e.g., algal diatoms), and accordingly restructuring of ordinary EPA to novel acids may take place in the sponge tissue.

  12. Anaerobic Biotransformation and Mobility of Pu and Pu-EDTA

    SciTech Connect

    Bolton, H., Jr.; Rai, D.; Xun, L.

    2005-04-18

    The complexation of radionuclides (e.g., plutonium (Pu) and {sup 60}Co) by codisposed ethylenediaminetetraacetate (EDTA) has enhanced their transport in sediments at DOE sites. Our previous NABIR research investigated the aerobic biodegradation and biogeochemistry of Pu(IV)-EDTA. Plutonium(IV) forms stable complexes with EDTA under aerobic conditions and an aerobic EDTA degrading bacterium can degrade EDTA in the presence of Pu and decrease Pu mobility. However, our recent studies indicate that while Pu(IV)-EDTA is stable in simple aqueous systems, it is not stable in the presence of relatively soluble Fe(III) compounds (i.e., Fe(OH){sub 3}(s)--2-line ferrihydrite). Since most DOE sites have Fe(III) containing sediments, Pu(IV) in likely not the mobile form of Pu-EDTA in groundwater. The only other Pu-EDTA complex stable in groundwater relevant to DOE sites would be Pu(III)-EDTA, which only forms under anaerobic conditions. Research is therefore needed in this brand new project to investigate the biotransformation of Pu and Pu-EDTA under anaerobic conditions. The biotransformation of Pu and Pu-EDTA under various anaerobic regimes is poorly understood including the reduction kinetics of Pu(IV) to Pu(III) from soluble (Pu(IV)-EDTA) and insoluble Pu(IV) as PuO2(am) by metal reducing bacteria, the redox conditions required for this reduction, the strength of the Pu(III)-EDTA complex, how the Pu(III)-EDTA complex competes with other dominant anoxic soluble metals (e.g., Fe(II)), and the oxidation kinetics of Pu(III)-EDTA. Finally, the formation of a stable soluble Pu(III)-EDTA complex under anaerobic conditions would require degradation of the EDTA complex to limit Pu(III) transport in geologic environments. Anaerobic EDTA degrading microorganisms have not been isolated. These knowledge gaps preclude the development of a mechanistic understanding of how anaerobic conditions will influence Pu and Pu-EDTA fate and transport to assess, model, and design approaches to stop

  13. VITRIFICATION OF THAI NATIVE CATTLE OOCYTES: EFFECTS OF ETHYLENE GLYCOL CONCENTRATIONS AND EXPOSURE TIME, LINOLEIC ACID ALBUMIN AND CHOLESTEROL-LOADED METHYL-B-CYCLODEXTRIN.

    PubMed

    Chasombat, Jakkhaphan; Vongpralub, Thevin; Sirisathien, Saksiri; Phasuk, Yupin; Sonseeda, Pronjit

    2015-01-01

    The present study aimed to improve the oocyte vitrification procedure for preservation of Thai native cattle genetic resources. In Experiment I, oocytes were exposed to various doses (2%, 4% and 6%) of ethylene glycol (EG) in vitrification solution I (VS-I) for different equilibration times (10 or 20 min) before being exposed to VS-II and then subjected to vitrification. Experiment II was divided into two parts: (a) oocytes were matured in medium supplemented with linoleic acid albumin (LAA) (1% or 2%) and then vitrified; (b) matured oocytes were preincubated with cholesterol-loaded methyl-β-cyclodextrin (CLC) (1% or 2%) and then vitrified. Equilibration of oocytes by exposure to 6% EG in VS-I for 10 min (Experiment I), and in vitro maturation of immature oocytes in medium supplementation with 2% LAA (Experiment II) were the most effective methods; vitrified/thawed oocytes showed higher rates of survival and subsequent embryonic development compared with the other experimental groups. PMID:26510334

  14. Chromatographic separation of proteins on metal immobilized iminodiacetic acid-bound molded monolithic rods of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate).

    PubMed

    Luo, Q; Zou, H; Xiao, X; Guo, Z; Kong, L; Mao, X

    2001-08-17

    Continuous rod of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate) was prepared by a free radical polymerization within the confines of a stainless-steel column. The epoxide groups of the rod were modified by a reaction with iminodiacetic acid (IDA) that affords the active site to form metal IDA chelates used for immobilized metal affinity chromatography (IMAC). The efficiency of coupling of IDA to the epoxide-contained matrix was studied as a function of reaction time and temperature. High-performance separation of proteins, based on immobilized different metals on the column, were described. The influence of pH on the adsorption capacity of bovine serum albumin on the Cu2+-IDA continuous rod column was investigated in the range from 5.0 to 9.0. Purification of lysozyme from egg white and human serum albumin (HSA) on the commercially available HSA solution were performed on the naked IDA and Cu2+-IDA continuous rod columns, respectively; and the purity of the obtained fractions was detected by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. PMID:11556331

  15. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    NASA Astrophysics Data System (ADS)

    Islas, Luisa; Ruiz, Juan-Carlos; Muñoz-Muñoz, Franklin; Isoshima, Takashi; Burillo, Guillermina

    2016-10-01

    Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from 60Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C1s and O1s content at the catheter's surface, revealed that the catheter's surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC's Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  16. Property tuning of poly(lactic acid)/cellulose bio-composites through blending with modified ethylene-vinyl acetate copolymer.

    PubMed

    Pracella, Mariano; Haque, Md Minhaz-Ul; Paci, Massimo; Alvarez, Vera

    2016-02-10

    The effect of addition of an ethylene-vinyl acetate copolymer modified with glycidyl methacrylate (EVA-GMA) on the structure and properties of poly(lactic acid) (PLA) composites with cellulose micro fibres (CF) was investigated. Binary (PLA/CF) and ternary (PLA/EVA-GMA/CF) composites obtained by melt mixing in Brabender mixer were analysed by SEM, POM, WAXS, DSC, TGA and tensile tests. The miscibility and morphology of PLA/EVA-GMA blends were first examined as a function of composition: a large rise of PLA spherulite growth rate in the blends was discovered with increasing the EVA-GMA content (0-30 wt%) in the isothermal crystallization both from the melt and the solid state. PLA/EVA-GMA/CF ternary composites displayed improved adhesion and dispersion of fibres into the matrix as compared to PLA/CF system. Marked changes of thermodynamic and tensile parameters, as elastic modulus, strength and elongation at break were observed for the composites, depending on blend composition, polymer miscibility and fibre-matrix chemical interactions at the interface.

  17. Fabrication of honeycomb-structured poly(ethylene glycol)-block-poly(lactic acid) porous films and biomedical applications for cell growth

    NASA Astrophysics Data System (ADS)

    Yao, Bingjian; Zhu, Qingzeng; Yao, Linli; Hao, Jingcheng

    2015-03-01

    A series of poly(ethylene glycol)-block-poly(lactic acid) (PEG-PLA) copolymers with a hydrophobic PLA block of different molecular weights and a fixed length hydrophilic PEG were synthesized successfully and characterized. These amphiphilic block copolymers were used to fabricate honeycomb-structured porous films using the breath figure (BF) templating technique. The surface topology and composition of the highly ordered pattern film were further characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy. The results indicated that the PEG-to-PLA block molecular weight ratio influenced the BF film surface topology. The film with the best ordered pores was obtained with a PEG-to-PLA ratio of 2.0 × 103:3.0 × 104. The self-organization of the hydrophilic PEG chains within the pores was confirmed by XPS and fluorescence labeled PEG. A model is proposed to elucidate the stabilization process of the amphiphilic PEG-PLA aggregated architecture on the water droplet-based templates. In addition, GFP-U87 cell viability has been investigated by MTS test and the cell morphology on the honeycomb-structured PEG-PLA porous film has been evaluated using phase-contrast microscope. This porous film is shown to be suitable as a matrix for cell growth.

  18. Property tuning of poly(lactic acid)/cellulose bio-composites through blending with modified ethylene-vinyl acetate copolymer.

    PubMed

    Pracella, Mariano; Haque, Md Minhaz-Ul; Paci, Massimo; Alvarez, Vera

    2016-02-10

    The effect of addition of an ethylene-vinyl acetate copolymer modified with glycidyl methacrylate (EVA-GMA) on the structure and properties of poly(lactic acid) (PLA) composites with cellulose micro fibres (CF) was investigated. Binary (PLA/CF) and ternary (PLA/EVA-GMA/CF) composites obtained by melt mixing in Brabender mixer were analysed by SEM, POM, WAXS, DSC, TGA and tensile tests. The miscibility and morphology of PLA/EVA-GMA blends were first examined as a function of composition: a large rise of PLA spherulite growth rate in the blends was discovered with increasing the EVA-GMA content (0-30 wt%) in the isothermal crystallization both from the melt and the solid state. PLA/EVA-GMA/CF ternary composites displayed improved adhesion and dispersion of fibres into the matrix as compared to PLA/CF system. Marked changes of thermodynamic and tensile parameters, as elastic modulus, strength and elongation at break were observed for the composites, depending on blend composition, polymer miscibility and fibre-matrix chemical interactions at the interface. PMID:26686158

  19. CO2-free power generation on an iron group nanoalloy catalyst via selective oxidation of ethylene glycol to oxalic acid in alkaline media.

    PubMed

    Matsumoto, Takeshi; Sadakiyo, Masaaki; Ooi, Mei Lee; Kitano, Sho; Yamamoto, Tomokazu; Matsumura, Syo; Kato, Kenichi; Takeguchi, Tatsuya; Yamauchi, Miho

    2014-07-08

    An Fe group ternary nanoalloy (NA) catalyst enabled selective electrocatalysis towards CO2-free power generation from highly deliverable ethylene glycol (EG). A solid-solution-type FeCoNi NA catalyst supported on carbon was prepared by a two-step reduction method. High-resolution electron microscopy techniques identified atomic-level mixing of constituent elements in the nanoalloy. We examined the distribution of oxidised species, including CO2, produced on the FeCoNi nanoalloy catalyst in the EG electrooxidation under alkaline conditions. The FeCoNi nanoalloy catalyst exhibited the highest selectivities toward the formation of C2 products and to oxalic acid, i.e., 99 and 60%, respectively, at 0.4 V vs. the reversible hydrogen electrode (RHE), without CO2 generation. We successfully generated power by a direct EG alkaline fuel cell employing the FeCoNi nanoalloy catalyst and a solid-oxide electrolyte with oxygen reduction ability, i.e., a completely precious-metal-free system.

  20. Structural tailoring of hydrogen-bonded poly(acrylic acid)/poly(ethylene oxide) multilayer thin films for reduced gas permeability.

    PubMed

    Xiang, Fangming; Ward, Sarah M; Givens, Tara M; Grunlan, Jaime C

    2015-02-01

    Hydrogen bonded poly(acrylic acid) (PAA)/poly(ethylene oxide) (PEO) layer-by-layer assemblies are highly elastomeric, but more permeable than ionically bonded thin films. In order to expand the use of hydrogen-bonded assemblies to applications that require a better gas barrier, the effect of assembling pH on the oxygen permeability of PAA/PEO multilayer thin films was investigated. Altering the assembling pH leads to significant changes in phase morphology and bonding. The amount of intermolecular hydrogen bonding between PAA and PEO is found to increase with increasing pH due to reduction of COOH dimers between PAA chains. This improved bonding leads to smaller PEO domains and lower gas permeability. Further increasing the pH beyond 2.75 results in higher oxygen permeability due to partial deprotonation of PAA. By setting the assembling pH at 2.75, the negative impacts of COOH dimer formation and PAA ionization on intermolecular hydrogen bonding can be minimized, leading to a 50% reduction in the oxygen permeability of the PAA/PEO thin film. A 20 bilayer coating reduces the oxygen transmission rate of a 1.58 mm natural rubber substrate by 20 ×. These unique nanocoatings provide the opportunity to impart a gas barrier to elastomeric substrates without altering their mechanical behavior.

  1. Biological and Tribological Assessment of Poly(Ethylene Oxide Terephthalate)/Poly(Butylene Terephthalate), Polycaprolactone, and Poly (L\\DL) Lactic Acid Plotted Scaffolds for Skeletal Tissue Regeneration.

    PubMed

    Hendrikson, Wilhelmus J; Zeng, Xiangqiong; Rouwkema, Jeroen; van Blitterswijk, Clemens A; van der Heide, Emile; Moroni, Lorenzo

    2016-01-21

    Additive manufactured scaffolds are fabricated from three commonly used biomaterials, polycaprolactone (PCL), poly (L\\DL) lactic acid (P(L\\DL)LA), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT). Scaffolds are compared biologically and tribologically. Cell-seeded PEOT/PBT scaffolds cultured in osteogenic and chondrogenic differentiation media show statistical significantly higher alkaline phosphatase (ALP) activity/DNA and glycosaminoglycans (GAG)/DNA ratios, followed by PCL and P(L\\DL)LA scaffolds, respectively. The tribological performance is assessed by determining the friction coefficients of the scaffolds at different loads and sliding velocities. With increasing load or decreasing sliding velocity, the friction coefficient value decreases. PEOT/PBT show to have the lowest friction coefficient value, followed by PCL and P(L\\DL)LA. The influence of the scaffold architecture is further determined with PEOT/PBT. Reducing of the fiber spacing results in a lower friction coefficient value. The best and the worst performing scaffold architecture are chosen to investigate the effect of cell culture on the friction coefficient. Matrix deposition is low in the cell-seeded scaffolds and the effect is, therefore, undetermined. Taken together, our studies show that PEOT/PBT scaffolds support better skeletal differentiation of seeded stromal cells and lower friction coefficient compared to PCL and P(L/DL)A scaffolds.

  2. One-Way Multishape-Memory Effect and Tunable Two-Way Shape Memory Effect of Ionomer Poly(ethylene-co-methacrylic acid).

    PubMed

    Lu, Lu; Li, Guoqiang

    2016-06-15

    Reversible elongation by cooling and contraction by heating, without the need for repeated programming, is well-known as the two-way shape-memory effect (2W-SME). This behavior is contrary to the common physics-contraction when cooling and expansion when heating. Materials with such behavior may find many applications in real life, such as self-sufficient grippers, fastening devices, optical gratings, soft actuators, and sealant. Here, it is shown that ionomer Surlyn 8940, a 50-year old polymer, exhibits both one-way multishape-memory effects and tunable two-way reversible actuation. The required external tensile stress to trigger the tunable 2W-SME is very low when randomly jumping the temperatures within the melting transition window. With a proper one-time programming, "true" 2W-SME (i.e., 2W-SME without the need for an external tensile load) is also achieved. A long training process is not needed to trigger the tunable 2W-SME. Instead, a proper one-time tensile programming is sufficient to trigger repeated and tunable 2W-SME. Because the 2W-SME of the ionomer Surlyn is driven by the thermally reversible network, here crystallization and melting transitions of the semicrystalline poly(ethylene-co-methacrylic acid), it is believed that a class of thermally reversible polymers should also exhibit tunable 2W-SMEs. PMID:27191832

  3. Hindered Diffusion of Oligosaccharides in High Strength Poly(ethylene glycol)/Poly(acrylic acid) Interpenetrating Network Hydrogels: Hydrodynamic Versus Obstruction Models

    PubMed Central

    Waters, Dale J.; Frank, Curtis W.

    2010-01-01

    Diffusion coefficients of small oligosaccharides within high strength poly(ethylene glycol)/poly(acrylic acid) interpenetrating network (PEG/PAA IPN) hydrogels were measured by diffusion through hydrogel slabs. The ability of hindered diffusion models previously presented in the literature to fit the experimental data is examined. A model based solely on effects due to hydrodynamics is compared to a model based solely on solute obstruction. To examine the effect of polymer volume fraction on the observed diffusion coefficients, the equilibrium volume fraction of polymer in PEG/PAA IPNs was systematically varied by changing the initial PEG polymer concentration in hydrogel precursor solutions from 20 to 50 wt./wt.%. To examine the effect of solute radius on the observed diffusion coefficients, solute radii were varied from 3.3 to 5.1 Å by measuring diffusion coefficients of glucose, a monosaccharide; maltose, a disaccharide; and maltotriose, a trisaccharide. Both the hydrodynamic and obstruction models rely on scaling relationships to predict diffusion coefficients. The proper scaling relationship for each of the hindered diffusion models is evaluated based on fits to experimental data. The scaling relationship employed is found to have a greater significance for the hydrodynamic model than the obstruction model. Regardless of the scaling relationship employed, the obstruction model provides a better fit to our experimental data than the hydrodynamic model. PMID:20514136

  4. Cooperation of Amphiphilicity and Crystallization for Regulating the Self-Assembly of Poly(ethylene glycol)-block-poly(lactic acid) Copolymers.

    PubMed

    Wang, Zhen; Cao, Yuanyuan; Song, Jiaqi; Xie, Zhigang; Wang, Yapei

    2016-09-20

    Tuning the amphiphilicity of block copolymers has been extensively exploited to manipulate the morphological transition of aggregates. The introduction of crystallizable moieties into the amphiphilic copolymers also offers increasing possibilities for regulating self-assembled structures. In this work, we demonstrate a detailed investigation of the self-assembly behavior of amphiphilic poly(ethylene glycol)-block-poly(l-lactic acid) (PEG-b-PLLA) diblock copolymers with the assistance of a common solvent in aqueous solution. With a given length of the PEG block, the molecular weight of the PLA block has great effect on the morphologies of self-assembled nanoaggregates as a result of varying molecular amphiphilicity and polymer crystallization. Common solvents including N,N-dimethylformamide, dioxane, and tetrahydrofuran involved in the early stage of self-assembly led to the change in chain configuration, which further influences the self-assembly of block copolymers. This study expanded the scope of PLA-based copolymers and proposed a possible mechanism of the sphere-to-lozenge and platelet-to-cylinder morphological transitions. PMID:27496056

  5. Facile and controllable preparation of mesoporous TiO2 using poly(ethylene glycol) as structure-directing agent and peroxotitanic acid as precursor

    NASA Astrophysics Data System (ADS)

    Nguyen, Dongthanh; Wang, Wei; Long, Haibo; Ru, Hongqiang

    2016-09-01

    This work demonstrated that mesoporous TiO2 (meso-TiO2) with controllable mesoporous and crystalline structures can be facilely prepared by using poly (ethylene glycol) (PEG) as structure-directing (SD) agent and peroxotitanic acid (PTA) as precursor. Meso-TiO2 with high specific surface area (157 m2•g-1), pore volume (0.45 cm3•g-1) and large mesopore size of 13.9 nm can be obtained after calcination at 450°C. Such meso-TiO2 also shows relatively high thermal stability. BET surface area still reaches 114 m2•g-1 after calcination at 550°C. In the synthesis and calcination process, PEG that plays multiple and important roles in delivering thermally stable and tunable mesoporous and crystalline structures shows to be a suitable low-cost SD agent for the controllable preparation of nanocrystalline meso-TiO2. The photocatalytic activity tests show that both high surface area and bi-crystallinity of obtained meso-TiO2 are important in enhancing the performance in photo-decomposing Rhodamine B in water.

  6. One-Way Multishape-Memory Effect and Tunable Two-Way Shape Memory Effect of Ionomer Poly(ethylene-co-methacrylic acid).

    PubMed

    Lu, Lu; Li, Guoqiang

    2016-06-15

    Reversible elongation by cooling and contraction by heating, without the need for repeated programming, is well-known as the two-way shape-memory effect (2W-SME). This behavior is contrary to the common physics-contraction when cooling and expansion when heating. Materials with such behavior may find many applications in real life, such as self-sufficient grippers, fastening devices, optical gratings, soft actuators, and sealant. Here, it is shown that ionomer Surlyn 8940, a 50-year old polymer, exhibits both one-way multishape-memory effects and tunable two-way reversible actuation. The required external tensile stress to trigger the tunable 2W-SME is very low when randomly jumping the temperatures within the melting transition window. With a proper one-time programming, "true" 2W-SME (i.e., 2W-SME without the need for an external tensile load) is also achieved. A long training process is not needed to trigger the tunable 2W-SME. Instead, a proper one-time tensile programming is sufficient to trigger repeated and tunable 2W-SME. Because the 2W-SME of the ionomer Surlyn is driven by the thermally reversible network, here crystallization and melting transitions of the semicrystalline poly(ethylene-co-methacrylic acid), it is believed that a class of thermally reversible polymers should also exhibit tunable 2W-SMEs.

  7. Biological and Tribological Assessment of Poly(Ethylene Oxide Terephthalate)/Poly(Butylene Terephthalate), Polycaprolactone, and Poly (L\\DL) Lactic Acid Plotted Scaffolds for Skeletal Tissue Regeneration.

    PubMed

    Hendrikson, Wilhelmus J; Zeng, Xiangqiong; Rouwkema, Jeroen; van Blitterswijk, Clemens A; van der Heide, Emile; Moroni, Lorenzo

    2016-01-21

    Additive manufactured scaffolds are fabricated from three commonly used biomaterials, polycaprolactone (PCL), poly (L\\DL) lactic acid (P(L\\DL)LA), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT). Scaffolds are compared biologically and tribologically. Cell-seeded PEOT/PBT scaffolds cultured in osteogenic and chondrogenic differentiation media show statistical significantly higher alkaline phosphatase (ALP) activity/DNA and glycosaminoglycans (GAG)/DNA ratios, followed by PCL and P(L\\DL)LA scaffolds, respectively. The tribological performance is assessed by determining the friction coefficients of the scaffolds at different loads and sliding velocities. With increasing load or decreasing sliding velocity, the friction coefficient value decreases. PEOT/PBT show to have the lowest friction coefficient value, followed by PCL and P(L\\DL)LA. The influence of the scaffold architecture is further determined with PEOT/PBT. Reducing of the fiber spacing results in a lower friction coefficient value. The best and the worst performing scaffold architecture are chosen to investigate the effect of cell culture on the friction coefficient. Matrix deposition is low in the cell-seeded scaffolds and the effect is, therefore, undetermined. Taken together, our studies show that PEOT/PBT scaffolds support better skeletal differentiation of seeded stromal cells and lower friction coefficient compared to PCL and P(L/DL)A scaffolds. PMID:26775915

  8. Flow Cytometry Method Analysis of Apoptosis: No Significant Difference Between EDTA and EDTA-free Trypsin Treatment Procedure.

    PubMed

    Xu, Xiao-yan; Nie, Xiao-cui; Ma, Hai-ying; Song, Guo-qing; Zhang, Xiao-tong; Jin, Yu-nan; Yu, Yan-qiu

    2015-04-01

    Flow cytometry method (FCM) is a generally accepted tool to analyze apoptosis. Although apoptosis assay kit was applied by many companies, the manufacturers were not consistent with whether using Trypsin with EDTA to collect the adherent cells. In another words, the influence of EDTA on apoptotic ratio is not clear. In this work, we compared the proportion of apoptotic cells with EDTA or EDTA-free Trypsin treatment by FCM. We concluded that Trypsin with or without EDTA has little influence on the proportion of apoptotic cells. In addition, we found that the ratio of necrosis and apoptosis was different in cells collected by scraping. WAVE2 protein was analyzed as a typical example for movement related protein. WAVE2 expression is elevated in the EDTA Trypsin treated group, compared with EDTA-free Trypsin treatment and scrapping group.

  9. Ethylene glycol, hazardous substance in the household.

    PubMed

    Patocka, Jirí; Hon, Zdenek

    2010-01-01

    Ethylene glycol is a colorless, odorless, sweet-tasting but poisonous type of alcohol found in many household products. The major use of ethylene glycol is as an antifreeze in, for example, automobiles, in air conditioning systems, in de-icing fluid for windshields, and else. People sometimes drink ethylene glycol mistakenly or on purpose as a substitute for alcohol. Ethylene glycol is toxic, and its drinking should be considered a medical emergency. The major danger from ethylene glycol is following ingestion. Due to its sweet taste, peoples and occasionally animals will sometimes consume large quantities of it if given access to antifreeze. While ethylene glycol itself has a relatively low degree of toxicity, its metabolites are responsible for extensive cellular damage to various tissues, especially the kidneys. This injury is caused by the metabolites, glycolic and oxalic acid and their respective salts, through crystal formation and possibly other mechanisms. Toxic metabolites of ethylene glycol can damage the brain, liver, kidneys, and lungs. The poisoning causes disturbances in the metabolism pathways, including metabolic acidosis. The disturbances may be severe enough to cause profound shock, organ failure, and death. Ethylene glycol is a common poisoning requiring antidotal treatment. PMID:20608228

  10. Leptosphaeria maculans effector AvrLm4-7 affects salicylic acid (SA) and ethylene (ET) signalling and hydrogen peroxide (H2 O2 ) accumulation in Brassica napus.

    PubMed

    Nováková, Miroslava; Šašek, Vladimír; Trdá, Lucie; Krutinová, Hana; Mongin, Thomas; Valentová, Olga; Balesdent, Marie-HelEne; Rouxel, Thierry; Burketová, Lenka

    2016-08-01

    To achieve host colonization, successful pathogens need to overcome plant basal defences. For this, (hemi)biotrophic pathogens secrete effectors that interfere with a range of physiological processes of the host plant. AvrLm4-7 is one of the cloned effectors from the hemibiotrophic fungus Leptosphaeria maculans 'brassicaceae' infecting mainly oilseed rape (Brassica napus). Although its mode of action is still unknown, AvrLm4-7 is strongly involved in L. maculans virulence. Here, we investigated the effect of AvrLm4-7 on plant defence responses in a susceptible cultivar of B. napus. Using two isogenic L. maculans isolates differing in the presence of a functional AvrLm4-7 allele [absence ('a4a7') and presence ('A4A7') of the allele], the plant hormone concentrations, defence-related gene transcription and reactive oxygen species (ROS) accumulation were analysed in infected B. napus cotyledons. Various components of the plant immune system were affected. Infection with the 'A4A7' isolate caused suppression of salicylic acid- and ethylene-dependent signalling, the pathways regulating an effective defence against L. maculans infection. Furthermore, ROS accumulation was decreased in cotyledons infected with the 'A4A7' isolate. Treatment with an antioxidant agent, ascorbic acid, increased the aggressiveness of the 'a4a7' L. maculans isolate, but not that of the 'A4A7' isolate. Together, our results suggest that the increased aggressiveness of the 'A4A7' L. maculans isolate could be caused by defects in ROS-dependent defence and/or linked to suppressed SA and ET signalling. This is the first study to provide insights into the manipulation of B. napus defence responses by an effector of L. maculans. PMID:26575525

  11. Cerato-platanin induces resistance in Arabidopsis leaves through stomatal perception, overexpression of salicylic acid- and ethylene-signalling genes and camalexin biosynthesis.

    PubMed

    Baccelli, Ivan; Lombardi, Lara; Luti, Simone; Bernardi, Rodolfo; Picciarelli, Piero; Scala, Aniello; Pazzagli, Luigia

    2014-01-01

    Microbe-associated molecular patterns (MAMPs) lead to the activation of the first line of plant defence. Few fungal molecules are universally qualified as MAMPs, and proteins belonging to the cerato-platanin protein (CPP) family seem to possess these features. Cerato-platanin (CP) is the name-giving protein of the CPP family and is produced by Ceratocystis platani, the causal agent of the canker stain disease of plane trees (Platanus spp.). On plane tree leaves, the biological activity of CP has been widely studied. Once applied on the leaf surface, CP acts as an elicitor of defence responses. The molecular mechanism by which CP elicits leaves is still unknown, and the protective effect of CP against virulent pathogens has not been clearly demonstrated. In the present study, we tried to address these questions in the model plant Arabidopsis thaliana. Our results suggest that stomata rapidly sense CP since they responded to the treatment with ROS signalling and stomatal closure, and that CP triggers salicylic acid (SA)- and ethylene (ET)-signalling pathways, but not the jasmonic acid (JA)-signalling pathway, as revealed by the expression pattern of 20 marker genes. Among these, EDS1, PAD4, NPR1, GRX480, WRKY70, ACS6, ERF1a/b, COI1, MYC2, PDF1.2a and the pathogenesis-related (PR) genes 1-5. CP rapidly induced MAPK phosphorylation and induced the biosynthesis of camalexin within 12 hours following treatment. The induction of localised resistance was shown by a reduced susceptibility of the leaves to the infection with Botrytis cinerea and Pseudomonas syringae pv. tomato. These results contribute to elucidate the key steps of the signalling process underlying the resistance induction in plants by CP and point out the central role played by the stomata in this process.

  12. A lipoxygenase from red alga Pyropia haitanensis, a unique enzyme catalyzing the free radical reactions of polyunsaturated fatty acids with triple ethylenic bonds.

    PubMed

    Zhu, Zhujun; Qian, Feijian; Yang, Rui; Chen, Juanjuan; Luo, Qijun; Chen, Haimin; Yan, Xiaojun

    2015-01-01

    Lipoxygenases (LOXs) are key enzymes to regulate the production of hormones and defensive metabolites in plants, animals and algae. In this research, a full length LOX gene has been cloned and expressed from the red alga Pyropia haitanensis (Bangiales, Rhodophyta) gametophyte (PhLOX2). Subsequent phylogenetic analysis showed that such LOX enzymes are separated at the early stage of evolution, establishing an independent branch. The LOX activity was investigated at the optimal pH of 8.0. It appears that PhLOX2 is a multifunctional enzyme featuring both lipoxygenase and hydroperoxidase activities. Additionally, PhLOX2 exhibits remarkable substrate and position flexibility, and it can catalyze an array of chemical reactions involving various polyunsaturated fatty acids, ranging from C18 to C22. As a matter of fact, mono-hydroperoxy, di-hydroperoxy and hydroxyl products have been obtained from such transformations, and eicosapentaenoic acid seem to be the most preferred substrate. It was found that at least triple ethylenic bonds are required for PhLOX2 to function as a LOX, and the resulting hydroxy products should be originated from the PhLOX2 mediated reduction of mono-hydroperoxides, in which the hydrogen abstraction occurs on the carbon atom between the second and third double bond. Most of the di-hydroperoxides observed seem to be missing their mono-position precursors. The substrate and position flexibility, as well as the function versatility of PhLOXs represent the ancient enzymatic pathway for organisms to control intracellular oxylipins.

  13. A Lipoxygenase from Red Alga Pyropia haitanensis, a Unique Enzyme Catalyzing the Free Radical Reactions of Polyunsaturated Fatty Acids with Triple Ethylenic Bonds

    PubMed Central

    Zhu, Zhujun; Qian, Feijian; Yang, Rui; Chen, Juanjuan; Luo, Qijun; Chen, Haimin; Yan, Xiaojun

    2015-01-01

    Lipoxygenases (LOXs) are key enzymes to regulate the production of hormones and defensive metabolites in plants, animals and algae. In this research, a full length LOX gene has been cloned and expressed from the red alga Pyropia haitanensis (Bangiales, Rhodophyta) gametophyte (PhLOX2). Subsequent phylogenetic analysis showed that such LOX enzymes are separated at the early stage of evolution, establishing an independent branch. The LOX activity was investigated at the optimal pH of 8.0. It appears that PhLOX2 is a multifunctional enzyme featuring both lipoxygenase and hydroperoxidase activities. Additionally, PhLOX2 exhibits remarkable substrate and position flexibility, and it can catalyze an array of chemical reactions involving various polyunsaturated fatty acids, ranging from C18 to C22. As a matter of fact, mono-hydroperoxy, di-hydroperoxy and hydroxyl products have been obtained from such transformations, and eicosapentaenoic acid seem to be the most preferred substrate. It was found that at least triple ethylenic bonds are required for PhLOX2 to function as a LOX, and the resulting hydroxy products should be originated from the PhLOX2 mediated reduction of mono-hydroperoxides, in which the hydrogen abstraction occurs on the carbon atom between the second and third double bond. Most of the di-hydroperoxides observed seem to be missing their mono-position precursors. The substrate and position flexibility, as well as the function versatility of PhLOXs represent the ancient enzymatic pathway for organisms to control intracellular oxylipins. PMID:25658744

  14. After-ripening induced transcriptional changes of hormonal genes in wheat seeds: the cases of brassinosteroids, ethylene, cytokinin and salicylic acid.

    PubMed

    Chitnis, Vijaya R; Gao, Feng; Yao, Zhen; Jordan, Mark C; Park, Seokhoon; Ayele, Belay T

    2014-01-01

    Maintenance and release of seed dormancy is regulated by plant hormones; their levels and seed sensitivity being the critical factors. This study reports transcriptional regulation of brassinosteroids (BR), ethylene (ET), cytokinin (CK) and salicylic acid (SA) related wheat genes by after-ripening, a period of dry storage that decays dormancy. Changes in the expression of hormonal genes due to seed after-ripening did not occur in the anhydrobiotic state but rather in the hydrated state. After-ripening induced dormancy decay appears to be associated with imbibition mediated increase in the synthesis and signalling of BR, via transcriptional activation of de-etiolated2, dwarf4 and brassinosteroid signaling kinase, and repression of brassinosteroid insensitive 2. Our analysis is also suggestive of the significance of increased ET production, as reflected by enhanced transcription of 1-aminocyclopropane-1-carboxylic acid oxidase in after-ripened seeds, and tight regulation of seed response to ET in regulating dormancy decay. Differential transcriptions of lonely guy, zeatin O-glucosyltransferases and cytokinin oxidases, and pseudo-response regulator between dormant and after-ripened seeds implicate CK in the regulation of seed dormancy in wheat. Our analysis also reflects the association of dormancy decay in wheat with seed SA level and NPR independent SA signaling that appear to be regulated transcriptionally by phenylalanine ammonia lyase, and whirly and suppressor of npr1 inducible1 genes, respectively. Co-expression clustering of the hormonal genes implies the significance of synergistic and antagonistic interaction between the different plant hormones in regulating wheat seed dormancy. These results contribute to further our understanding of the molecular features controlling seed dormancy in wheat.

  15. Photoelectrocatalytic oxidation of Cu(II)-EDTA at the TiO2 electrode and simultaneous recovery of Cu(II) by electrodeposition.

    PubMed

    Zhao, Xu; Guo, Libao; Zhang, Baofeng; Liu, Huijuan; Qu, Jiuhui

    2013-05-01

    The simultaneous decomplexation of Cu-EDTA and electrodeposition recovery of Cu(2+) ions was attempted in a photoelectrocatalytic (PEC) system using TiO2/Ti as the anode and stainless steel as the cathode. At a current density of 0.5 mA/cm(2), removal efficiencies of 0.05 mM Cu-EDTA by photocatalysis, electrooxidation, and PEC processes were determined to be 15, 43, and 72% at 3 h, respectively. Recovery percentages of Cu(2+) ions were determined to be 10, 33, and 67%, respectively. These results indicated that a synergetic effect in the decomplexation of Cu-EDTA and recovery of Cu(2+) ions occurred in the PEC process, which favored acid conditions and increased with the current densities. The removal of Cu-EDTA and Cu(2+) ions can be described by a pseudo-first-order kinetics model. Ca(2+) ions significantly increase the removal of Cu-EDTA and recovery of Cu(2+) ions. Intermediates, including Cu-NTA, Cu-EDDA, acetic acid, formic acid, and oxalic acid, were identified, and a decomplexation pathway of Cu-EDTA was proposed. The Cu-EDTA decomplexation at the anode via oxidation of hydroxyl radicals was revealed. On the basis of X-ray photoelectron spectra analysis, a reduction pathway of Cu(2+) ions at the cathode was discussed. The present study may provide a promising alternative for destruction of the metal complex and recovery of metal ions.

  16. Complexes of Imidazole with Poly(ethylene glycol) as a Corrosion Inhibitor for Carbon Steel in Sulphuric Acid

    NASA Astrophysics Data System (ADS)

    Salimi, Saeed; Nasr-Esfahani, Mojtaba; Umoren, Saviour A.; Saebnoori, Ehsan

    2015-12-01

    The inhibiting action of polyethylene glycol and imidazole (PEG/IMZ)) complexes prepared by a simple deprotonation procedure on carbon steel corrosion in 0.5 mol/L sulphuric acid was evaluated using the weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques complemented by surface analysis using scanning electron microscopy. The inhibiting effect of the PEG/IMZ complexes on carbon steel corrosion was compared with the non-complex forms. Results obtained show that PEG/IMZ complex is a very effective corrosion inhibitor of carbon steel in the acid environment. The inhibition efficiency increased with the increase in the temperature and also with increasing percentage of imidazole in the complex. Corrosion inhibition occurs by virtue of adsorption of PEG/IMZ complexes on the steel surface which was found to follow the Temkin adsorption isotherm model. The PEG/IMZ complexes function as a mixed-type inhibitor. Results from all the methods employed are in a reasonably good agreement.

  17. EDTA enhanced plant growth, antioxidant defense system, and phytoextraction of copper by Brassica napus L.

    PubMed

    Habiba, Ume; Ali, Shafaqat; Farid, Mujahid; Shakoor, Muhammad Bilal; Rizwan, Muhammad; Ibrahim, Muhammad; Abbasi, Ghulam Hasan; Hayat, Tahir; Ali, Basharat

    2015-01-01

    Copper (Cu) is an essential micronutrient for normal plant growth and development, but in excess, it is also toxic to plants. The present study investigated the influence of ethylenediaminetetraacetic acid (EDTA) in enhancing Cu uptake and tolerance as well as the morphological and physiological responses of Brassica napus L. seedlings under Cu stress. Four-week-old seedlings were transferred to hydroponics containing Hoagland's nutrient solution. After 2 weeks of transplanting, three levels (0, 50, and 100 μM) of Cu were applied with or without application of 2.5 mM EDTA and plants were further grown for 8 weeks in culture media. Results showed that Cu alone significantly decreased plant growth, biomass, photosynthetic pigments, and gas exchange characteristics. Cu stress also reduced the activities of antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein contents. Cu toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in both leaves and roots. The application of EDTA significantly alleviated Cu-induced toxic effects in B. napus, showing remarkable improvement in all these parameters. EDTA amendment increased the activity of antioxidant enzymes by decreasing the concentrations of MDA and H2O2 both in leaves and roots of B. napus. Although, EDTA amendment with Cu significantly increased Cu uptake in roots, stems, and leaves in decreasing order of concentration but increased the growth, photosynthetic parameters, and antioxidant enzymes. These results showed that the application of EDTA can be a useful strategy for phytoextraction of Cu by B. napus from contaminated soils. PMID:25163559

  18. Combined Effect of Trolox and EDTA on Frozen-Thawed Sperm Quality

    PubMed Central

    Keshtgar, Sara; Iravanpour, Farideh; Gharesi-Fard, Behrooz; Kazerooni, Marjaneh

    2016-01-01

    The freezing and thawing process not only is associated with serious damage to sperm such as damage to the plasma membrane and the acrosomal membrane but also changes the membrane permeability to some ions including calcium. Also, the generation of oxygen free radicals is increased during the freezing-thawing process. The purpose of this study was to evaluate of the effects of Trolox as an antioxidant and edetic acid (EDTA) as a calcium chelator on frozen-thawed (FT) sperm and compare these effects with those on fresh sperm. This study was done on these men of 25 healthy men, who referred to Shiraz Infertility Centerbetween2012 and2013. Normal samples were transferred to the ReproductivePhysiology Laboratory, Department of Physiology, Shiraz University of Medical Sciences, Shiraz. The samples were divided into two groups randomly: fresh and FT sperm groups. Each group was divided into five subgroups: control group, the solvent group (0.1%dimethyl sulfoxide [DMSO]), Trolox group (200μM), EDTA group (1.1mM), and Trolox+EDTA group. The percentages of motility, viability, and acrosome-reacted sperm were tested. The percentages of motility and viability in the FT sperm were lower than those in the fresh sperm. The progressive motility of the FT sperm was improved nonsignificantly with Trolox+EDTA. However, the effect of Trolox+EDTA on the progressive motility of the FT sperm was much more than that on the fresh sperm. The fewest acrosome-reacted sperm were observed in the EDTA-containingFT sperm. Antioxidant supplementation or omission of extracellular calcium may partly improve motility and also reduce acrosomal damage in FT sperm. PMID:27217608

  19. EDTA enhanced plant growth, antioxidant defense system, and phytoextraction of copper by Brassica napus L.

    PubMed

    Habiba, Ume; Ali, Shafaqat; Farid, Mujahid; Shakoor, Muhammad Bilal; Rizwan, Muhammad; Ibrahim, Muhammad; Abbasi, Ghulam Hasan; Hayat, Tahir; Ali, Basharat

    2015-01-01

    Copper (Cu) is an essential micronutrient for normal plant growth and development, but in excess, it is also toxic to plants. The present study investigated the influence of ethylenediaminetetraacetic acid (EDTA) in enhancing Cu uptake and tolerance as well as the morphological and physiological responses of Brassica napus L. seedlings under Cu stress. Four-week-old seedlings were transferred to hydroponics containing Hoagland's nutrient solution. After 2 weeks of transplanting, three levels (0, 50, and 100 μM) of Cu were applied with or without application of 2.5 mM EDTA and plants were further grown for 8 weeks in culture media. Results showed that Cu alone significantly decreased plant growth, biomass, photosynthetic pigments, and gas exchange characteristics. Cu stress also reduced the activities of antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein contents. Cu toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in both leaves and roots. The application of EDTA significantly alleviated Cu-induced toxic effects in B. napus, showing remarkable improvement in all these parameters. EDTA amendment increased the activity of antioxidant enzymes by decreasing the concentrations of MDA and H2O2 both in leaves and roots of B. napus. Although, EDTA amendment with Cu significantly increased Cu uptake in roots, stems, and leaves in decreasing order of concentration but increased the growth, photosynthetic parameters, and antioxidant enzymes. These results showed that the application of EDTA can be a useful strategy for phytoextraction of Cu by B. napus from contaminated soils.

  20. Concomitant spuriously elevated white blood cell count, a previously underestimated phenomenon in EDTA-dependent pseudothrombocytopenia.

    PubMed

    Xiao, Yufei; Xu, Yang

    2015-01-01

    The proportion and potential risk of concomitant spuriously elevated white blood cell count (SEWC) are underestimated in ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia (PTCP). The proportion, kinetics and prevention of SEWC remain poorly understood. A total of 25 patients with EDTA-dependent PTCP were enrolled in this study. With the hematology analyzer Coulter LH 750, we determined the time courses of WBC count, WBC differential and platelet count in EDTA- and sodium citrate-anticoagulated blood, respectively. Blood smears were prepared to inspect the presence of platelet clumps using light microscopy. The effect of automatic instrumental correction on the extent of SEWC was evaluated. The proportion of SEWC was 92% in EDTA-dependent PTCP and 73.9% of SEWCs were within the normal range. The development of SEWC was time-dependent, and neutrophils and lymphocytes were the main subpopulations involved in SEWC. A strong and significant correlation (r = 0.9937, p < 0.001) was found between the increased WBC count and the decreased platelet count. Both corrected and uncorrected WBC counts at 15 minutes or later after blood collection in EDTA were significantly higher than their basal counts, respectively, p < 0.05. Interestingly, in citrated blood, WBC counts after blood collection were not significantly different from its basal counts, p > 0.05. A high proportion of concomitant SEWCs, which are mainly within normal range, are present in patients with EDTA-dependent PTCP. Proper interpretation of SEWC is crucial to avoid clinic errors. SEWC develops in a time-dependent pattern, although the Coulter LH 750 only partly mitigates the extent of SEWC, sodium citrate is able to effectively prevent SEWC.

  1. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Xun, Luying; Bolton, Jr., Harvey

    2002-06-01

    This project, by Dr. Xun, supports work at PNNL (Bolton) regarding plutonium mobility in the subsurface. Ethylenediaminetetraacetate (EDTA) is a chelating agent that can increase the mobility of radionuclides and heavy metals in groundwater. Biodegradation of EDTA can decrease the enhanced mobility. The overall objective is to understand how microbial degradation affects Plutonium-EDTA transport in the environment and the specific objective of this component is to understand how microorganisms degrade EDTA. A chelating degrading bacterium BNC1 can use EDTA and nitrilotriacetate (NTA) as sole carbon and nitrogen sources. A gene cluster responsible for both EDTA and NTA degradation has been cloned and characterized (1,2). The same enzymes are used to degrade both compounds except that additional enzymes are required for EDTA degradation. Since the enzymes are located inside cells, EDTA and NTA must be transported into cells for degradation. For the first funding year, we have focused on how EDTA and NTA are transported into BNC1 cells. The EDTA-degrading gene cluster also contains genes encoding a hypothetical ABC-type transporter. We first demonstrated that the transporter genes and EDTA monooxygenase gene (emoA) were co-transcribed by RT-PCR, suggesting that the genes are involved in EDTA transport. We then characterized one of the gene product EppA. Using recombinant EppA purified from Escherichia coli, we have shown that EppA binds several metal:EDTA complexes by fluorescence techniques. In addition, EppA is shown to bind Mg:NTA, Ca:NTA and Fe(III):NTA but not free NTA.

  2. How phytohormone IAA and chelator EDTA affect lead uptake by Zn/Cd hyperaccumulator Picris divaricata.

    PubMed

    Du, Rui-Jun; He, Er-Kai; Tang, Ye-Tao; Hu, Peng-Jie; Ying, Rong-Rong; Morel, Jean-Louis; Qiu, Rong-Liang

    2011-01-01

    In this paper, the effects of indole-3-acetic acid (IAA) and/or ethylenediaminetetraacetic acid (EDTA) on lead uptake by a Zn/Cd hyperaccumulator Picris divaricata were studied. P. divaricata responded to Pb by better root system and increased biomass in presence of phytohormone IAA, which was able to reduce the inhibiting effects of Pb on transpiration without reducing the uptake of Pb The application of 100 microM IAA increased plant transpiration rate by about 20% and Pb concentration in leaves by about 37.3% as compared to treatment exposed to Pb alone. The enhanced phytoextraction efficiency could be attributed to the mechanisms played by IAA through alleviating Pb toxicity, creating better root system and plant biomass, promoting a higher transpiration rate as well as regulating the level of nutrient elements. On the contrary, inefficiency of phytoextraction was found with EDTA or the combination of IAA and EDTA probably because most Pb was in the form of Pb-EDTA complex which blocked the uptake by P. divaricata. The present study demonstrated that IAA was able to enhance the phytoextraction of Pb by Zn/Cd hyperaccumulator P. divaricata, providing a feasible method for the phytoremediation of polymetallic contaminated soils. PMID:21972569

  3. Determination of EDTA in feed and premix formulations by HPLC-DAD.

    PubMed

    Chiumiento, Francesco; D'Aloise, Antonio; Marchegiani, Francesca; Melai, Valeria

    2015-05-15

    A simple analytical method for the quantitative determination of ethylenediaminetetraacetic acid (EDTA) in feed and premix formulations was developed and validated. The method involves an extraction with an acidic ferric chloride solution, to quantitatively convert EDTA species in the samples into the Fe(III)-EDTA complex, and its subsequent detection by Ion-Pair-Reversed Phase-High Performance Liquid Chromatography-Diode Array Detection (IP-RP-HPLC-DAD). A robust validation procedure was performed according to the Decision 2002/657/EC at concentrations ranging from 25 to 100 mg kg(-1) on sample. Good recoveries (85.6-92.8%) were obtained; repeatability of the method was in the range of 1.3-8.0%, with an intermediate precision ranging from 6.0% to 8.6%, both of them expressed as relative standard deviation (RSD). No interfering species hindered the straightforward detection of EDTA. Hence, the proposed method can be adopted for an effective and rapid routine analysis of products for livestock.

  4. Properties and mechanisms of drug release from matrix tablets containing poly(ethylene oxide) and poly(acrylic acid) as release retardants.

    PubMed

    Zhang, Feng; Meng, Fan; Lubach, Joseph; Koleng, Joseph; Watson, N A

    2016-08-01

    The interactions between poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) in aqueous medium at pH 6.8 were investigated in the current study. We have also studied the effect of interpolymer interactions and various formulation variables, including the molecular weight of PEO, the ratio between PEO and PAA, the crystallinity of PEO, and the presence of an acidifying agent, on the release of theophylline from matrix tablets containing both PEO and PAA as release retardants. At pH 6.8, the synergy in solution viscosity between PEO and PAA as the result of ion-dipole interaction was observed in this study. The release of theophylline from the matrix tablets containing physical mixtures of PEO and PAA was found to be a function of dissolution medium pH because of the pH-dependent interactions between these two polymers. Because of the formation of water insoluble interpolymer complex between PEO and PAA in aqueous medium at pH below 4.0, the release of theophylline was independent of PEO molecular weight and was controlled by Fickian diffusion mechanism in 0.01N hydrochloric acid solution. In comparison, the drug release was a function of PEO molecular weight and followed the anomalous transport mechanism in phosphate buffer pH 6.8. The presence of PAA exerted opposite effects on the release of theophylline in phosphate buffer pH 6.8. In one aspect, theophylline release was accelerated because the erosion of PAA was much faster than that of PEO at pH6.8. On the opposite aspect, theophylline release was slowed down because of the formation of insoluble complex inside the gel layer as the result of the acidic microenvironment induced by PAA, and the increase in the viscosity of the gel layer as the result of the synergy between PEO and PAA. These two opposite effects offset each other. As a result, the release of theophylline remained statistically the same even when 75% PEO in the formulation was replaced with PAA. In phosphate buffer pH 6.8, the release of

  5. Root formation in ethylene-insensitive plants.

    PubMed

    Clark, D G; Gubrium, E K; Barrett, J E; Nell, T A; Klee, H J

    1999-09-01

    Experiments with ethylene-insensitive tomato (Lycopersicon esculentum) and petunia (Petunia x hybrida) plants were conducted to determine if normal or adventitious root formation is affected by ethylene insensitivity. Ethylene-insensitive Never ripe (NR) tomato plants produced more below-ground root mass but fewer above-ground adventitious roots than wild-type Pearson plants. Applied auxin (indole-3-butyric acid) increased adventitious root formation on vegetative stem cuttings of wild-type plants but had little or no effect on rooting of NR plants. Reduced adventitious root formation was also observed in ethylene-insensitive transgenic petunia plants. Applied 1-aminocyclopropane-1-carboxylic acid increased adventitious root formation on vegetative stem cuttings from NR and wild-type plants, but NR cuttings produced fewer adventitious roots than wild-type cuttings. These data suggest that the promotive effect of auxin on adventitious rooting is influenced by ethylene responsiveness. Seedling root growth of tomato in response to mechanical impedance was also influenced by ethylene sensitivity. Ninety-six percent of wild-type seedlings germinated and grown on sand for 7 d grew normal roots into the medium, whereas 47% of NR seedlings displayed elongated tap-roots, shortened hypocotyls, and did not penetrate the medium. These data indicate that ethylene has a critical role in various responses of roots to environmental stimuli.

  6. M[superscript 2+]•EDTA Binding Affinities: A Modern Experiment in Thermodynamics for the Physical Chemistry Laboratory

    ERIC Educational Resources Information Center

    O'Brien, Leah C.; Root, Hannah B.; Wei, Chin-Chuan; Jensen, Drake; Shabestary, Nahid; De Meo, Cristina; Eder, Douglas J.

    2015-01-01

    Isothermal titration calorimetry was used to experimentally determine thermodynamic values for the ethylenediaminetetraacetic acid (EDTA)(aq) + M[superscript 2+](aq) reactions (M[superscript 2+] = Ca[superscript 2+] and Mg[superscript 2+]). Students showed that for reactions in a N-(2-hydroxyethyl)piperazine-N"-ethanesulfonic acid (HEPES)…

  7. Burst of ethylene upon horizontal placement of tomato seedlings

    NASA Technical Reports Server (NTRS)

    Harrison, M.; Pickard, B. G.

    1984-01-01

    Seedlings of Lycopersicon esculentum Mill. cv Rutgers emit a pulse of ethylene during the first 2 to 4 minutes following horizontal placement. Because this burst appears too rapid and brief to be mediated by increase in net activity of 1-aminocyclopropane-1-carboxylic acid synthase, it might result form accelerated transformation of vacuolar 1-aminocyclopropane-1-carboxylic acid to ethylene.

  8. Effect of adsorbed metals ions on the transport of Zn- and Ni-EDTA complexes in a sand and gravel aquifer

    USGS Publications Warehouse

    Kent, D.B.; Davis, J.A.; Anderson, L.C.D.; Rea, B.A.; Coston, J.A.

    2002-01-01

    Adsorption, complexation, and dissolution reactions strongly influenced the transport of metal ions complexed with ethylenediaminetetraacetic acid (EDTA) in a predominantly quartz-sand aquifer during two tracer tests conducted under mildly reducing conditions at pH 5.8 to 6.1. In tracer test M89, EDTA complexes of zinc (Zn) and nickel (Ni), along with excess free EDTA, were injected such that the lower portion of the tracer cloud traveled through a region with adsorbed manganese (Mn) and the upper portion of the tracer cloud traveled through a region with adsorbed Zn. In tracer test S89, Ni- and Zn-EDTA complexes, along with excess EDTA complexed with calcium (Ca), were injected into a region with adsorbed Mn. The only discernable chemical reaction between Ni-EDTA and the sediments was a small degree of reversible adsorption leading to minor retardation. In the absence of adsorbed Zn, the injected Zn was displaced from EDTA complexes by iron(III) [Fe(III)] dissolved from the sediments. Displacement of Zn by Fe(III) on EDTA became increasingly thermodynamically favorable with decreasing total EDTA concentration. The reaction was slow compared to the time-scale of transport. Free EDTA rapidly dissolved aluminum (Al) from the sediments, which was subsequently displaced slowly by Fe. In the portion of tracer cloud M89 that traveled through the region contaminated with adsorbed Zn, little displacement of Zn complexed with EDTA was observed, and Al was rapidly displaced from EDTA by Zn desorbed from the sediments, in agreement with equilibrium calculations. In tracer test S89, desorption of Mn dominated over the more thermodynamically favorable dissolution of Al oxyhydroxides. Comparison with results from M89 suggests that dissolution of Al oxyhydroxides in coatings on these sediment grains by Ca-EDTA was rate-limited whereas that by free EDTA reached equilibrium on the time-scale of transport. Rates of desorption are much faster than rates of dissolution of Fe

  9. Anaerobic Biotransformation and Mobility of Pu and Pu-EDTA

    SciTech Connect

    Bolton, H., Jr.; Bailey, V.L.; Plymale, A.E.; Rai, D.; Xun, L.

    2006-04-05

    The complexation of radionuclides (e.g., plutonium (Pu) and {sup 60}Co) by co-disposed ethylenediaminetetraacetate (EDTA) has enhanced their transport in sediments at DOE sites. Pu(IV)-EDTA is not stable in the presence of relatively soluble Fe(III) compounds. Since most DOE sites have Fe(III) containing sediments, Pu(IV) is likely not the mobile form of Pu-EDTA. The only other Pu-EDTA complex stable in groundwater relevant to DOE sites would be Pu(III)-EDTA, which only forms under anaerobic conditions. Research is therefore needed to investigate the biotransformation of Pu and Pu-EDTA under anaerobic conditions and the anaerobic biodegradation of Pu-EDTA. The biotransformation of Pu and Pu-EDTA under various anaerobic regimes is poorly understood including the reduction kinetics of Pu(IV) to Pu(III) from soluble (Pu(IV)-EDTA) and insoluble Pu(IV), the redox conditions required for this reduction, the strength of the Pu(III)-EDTA, how the Pu(III)-EDTA competes with other dominant anoxic soluble metals (e.g., Fe(II)), and the oxidation kinetics of Pu(III)-EDTA. Finally, soluble Pu(III)-EDTA under anaerobic conditions would require anaerobic degradation of the EDTA to limit Pu(III) transport. Anaerobic EDTA degrading microorganisms have never been isolated. Recent results have shown that Shewanella oneidensis MR-1, a dissimilatory metal reducing bacterium, can reduce Pu(IV) to Pu(III). The Pu(IV) was provided as insoluble PuO2. The highest rate of Pu(IV) reduction was with the addition of AQDS, an electron shuttle. Of the total amount of Pu solubilized (i.e., soluble through a 0.36 nm filter), approximately 70% was Pu(III). The amount of soluble Pu was between 4.8 and 3.2 micromolar at day 1 and 6, respectively, indicating rapid reduction. The micromolar Pu is significant since the drinking water limit for Pu is 10{sup -12} M. On-going experiments are investigating the influence of EDTA on the rate of Pu reduction and the stability of the formed Pu(III). We have also

  10. EDTA functionalized silica for removal of Cu(II), Zn(II) and Ni(II) from aqueous solution.

    PubMed

    Kumar, R; Barakat, M A; Daza, Y A; Woodcock, H L; Kuhn, J N

    2013-10-15

    Ethylenediaminetetraacetic acid (EDTA) functionalized silica adsorbent has been synthesized using (3-aminopropyl) triethoxylsilane (APTES) as a bridging link between silanol groups (SiOH) of silica and carboxylic group of EDTA. Fourier transform infrared spectroscopy (FTIR) and Temperature-programmed oxidation (TPO) analysis confirmed the grafting of EDTA onto the silica. The synthesized EDTA-silica was investigated as an adsorbent for removal of Cu(II), Zn(II) and Ni(II) from aqueous solution. The effect of solution pH, initial solution concentration, and contact time were studied. The removal of metal ions increased with the increase in solution pH, contact time and concentration. The maximum equilibrium time was found to be 45min for all three metal ions. Kinetics studies revealed that the adsorption of Cu(II), Zn(II) and Ni(II) onto EDTA-silica followed the pseudo-second order kinetics and film diffusion and intra-particle diffusion mechanism were involved. Adsorption equilibrium data were well fitted to Langmuir isotherm model and maximum monolayer adsorption capacity for Cu(II), Zn(II) and Ni(II) was 79.36, 74.07 and 67.56mg g(-1), respectively. Thermodynamic results reveal that the removal of metals onto EDTA-silica was endothermic and spontaneous in nature.

  11. Comparison of removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether)-N, N, N', N'-tetraacetic acid and citric acid in primary teeth: A scanning electron microscopic study

    PubMed Central

    Hegde, Rahul J.; Bapna, Kavita

    2016-01-01

    Background: Root canal irrigants are considered momentous in their tissue dissolving property, eliminating microorganisms, and removing smear layer. The present study was aimed to compare the removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether)-N, N, N', N'-tetraacetic acid (EGTA) and citric acid solutions with saline as a control in primary anterior teeth. Materials and Methods: Thirty primary anterior teeth were chosen for the study. The teeth were distributed into three groups having ten teeth each. Following instrumentation, root canals of the first group were treated with 17% EGTA and the second group with 6% citric acid. Only saline was used as an irrigant for the control group. Then, the teeth were subjected to scanning electron microscopy (SEM) study. The scale given by Rome et al. for the smear layer removal was used in the present study. Results: The pictures from the SEM showed that among the tested irrigants, 17% EGTA + 5% sodium hypochlorite (NaOCl) group showed the best results when compared to other groups. Conclusion: The results advocate that the sequential irrigation of the pulp canal walls with 17% EGTA followed by 5% NaOCl produced efficacious and smear-free root canal walls. PMID:27307670

  12. Structural and magnetic properties of magnesium ferrite nanoparticles prepared via EDTA-based sol-gel reaction

    NASA Astrophysics Data System (ADS)

    Hussein, Shaban I.; Elkady, Ashraf S.; Rashad, M. M.; Mostafa, A. G.; Megahid, R. M.

    2015-04-01

    Magnesium ferrite (MgFe2O4) nanoparticles have been prepared, for the first time, by ethylene diamine tetraacetic acid (EDTA)-based sol-gel combustion method. The prepared ferrite system is calcined at 400, 500 and 600 °C. Thermo-gravimetric and differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometry (VSM) were applied for elucidating the structural and magnetic properties of the prepared system. XRD patterns revealed that the prepared system have two spinel MgFe2O4 structures, namely cubic and tetragonal phases that are dependent on calcination temperature (Tc). The crystallite sizes varied from 8.933 to 41.583 nm, and from 1.379 to 292.565 nm for the cubic and tetragonal phases respectively depending on Tc. The deduced lattice parameters for the cubic and (tetragonal) systems are a=8.368, 8.365 and 8.377 and (a=7.011, 5.922, 5.908 and c=6.622, 8.456, 8.364) Å at Tc=400, 500 and 600 °C respectively. While the cation distribution of the cubic phase is found to be mixed spinel and Tc-dependent, it is an inverse spinel in the tetragonal phase where the Fe3+ ions occupy both the tetrahedral A- and octahedral B-sites in almost equal amount; the Mg2+ ions are found to occupy only the B-sites. The HRTEM and selected-area electron diffraction (SAED) revealed the detailed morphology of the nanoparticles, and confirmed their crystalline spinel structure. VSM indicated the existence of an appreciable fraction of superparamagnetic particles at room temperature, with pure superparamagnetic behavior observed for samples calcined at 400 °C. Besides, the magnetic properties are found to change by thermal treatment as a result of the varied phase concentration, cation distribution and lattice parameters. Thus, the new synthesis route used in this study by applying EDTA as an organic precursor for preparing MgFe2O4 nanoparticles at

  13. Determination of optimal sampling times for a two blood sample clearance method using (51)Cr-EDTA in cats.

    PubMed

    Vandermeulen, Eva; De Sadeleer, Carlos; Piepsz, Amy; Ham, Hamphrey R; Dobbeleir, André A; Vermeire, Simon T; Van Hoek, Ingrid M; Daminet, Sylvie; Slegers, Guido; Peremans, Kathelijne Y

    2010-08-01

    Estimation of the glomerular filtration rate (GFR) is a useful tool in the evaluation of kidney function in feline medicine. GFR can be determined by measuring the rate of tracer disappearance from the blood, and although these measurements are generally performed by multi-sampling techniques, simplified methods are more convenient in clinical practice. The optimal times for a simplified sampling strategy with two blood samples (2BS) for GFR measurement in cats using plasma (51)chromium ethylene diamine tetra-acetic acid ((51)Cr-EDTA) clearance were investigated. After intravenous administration of (51)Cr-EDTA, seven blood samples were obtained in 46 cats (19 euthyroid and 27 hyperthyroid cats, none with previously diagnosed chronic kidney disease (CKD)). The plasma clearance was then calculated from the seven point blood kinetics (7BS) and used for comparison to define the optimal sampling strategy by correlating different pairs of time points to the reference method. Mean GFR estimation for the reference method was 3.7+/-2.5 ml/min/kg (mean+/-standard deviation (SD)). Several pairs of sampling times were highly correlated with this reference method (r(2) > or = 0.980), with the best results when the first sample was taken 30 min after tracer injection and the second sample between 198 and 222 min after injection; or with the first sample at 36 min and the second at 234 or 240 min (r(2) for both combinations=0.984). Because of the similarity of GFR values obtained with the 2BS method in comparison to the values obtained with the 7BS reference method, the simplified method may offer an alternative for GFR estimation. Although a wide range of GFR values was found in the included group of cats, the applicability should be confirmed in cats suspected of renal disease and with confirmed CKD. Furthermore, although no indications of age-related effect were found in this study, a possible influence of age should be included in future studies. PMID:20452793

  14. Simultaneously degradation of 2,4-dichlorophenol and EDTA in aqueous solution by the bimetallic Cu-Fe/O₂ system.

    PubMed

    Liu, Xin; Fan, Jin-Hong; Ma, Lu-Ming

    2015-01-01

    Oxidative degradation of aqueous organic contaminants 2,4-dichlorophenol (2,4-DCP) using ethylenediaminetetraacetic acid (EDTA)-enhanced bimetallic Cu-Fe system in the presence of dissolved oxygen was investigated. The proposed process was applied for the pH range of 3~7 with the degradation efficiency of 2,4-DCP and EDTA varying within 10 %, and achieved at 100 % degradation of 40 mg L(-1) 2,4-DCP in 1 h, at the initial pH of 3, 25 g L(-1) of bimetallic Fe-Cu powder (WCu/WFe = 0.01289) and initial EDTA of 0.57 mM. However, the removal efficiency of 2,4-DCP in control tests were 7.52 % (Cu-Fe/O2 system) and 84.32 % (EDTA-enhanced Fe/O2 process), respectively, after 3 h, reaction. The proposed main mechanism, involves the in situ generation of H2O2 by the electron transfer from Fe(0) to O2 which was enhanced by ethylenediaminetetraacetic acid (EDTA), and the in situ generation of ·OH via advanced oxidation reaction. Accordingly, 2,4-DCP was attacked by ·OH to achieve complete dechlorination and low molecular weight organic acids, even mineralized. Systematic studies on the effects of initial EDTA and 2,4-DCP concentration, Cu-Fe dosing, Cu content, and pH revealed that these effects need to be optimized to avoid the excessive consumption of ·OH and new EDTA and heavy metal Cu pollution.

  15. High strength of physical hydrogels based on poly(acrylic acid)-g-poly(ethylene glycol) methyl ether: role of chain architecture on hydrogel properties.

    PubMed

    Yang, Jun; Gong, Cheng; Shi, Fu-Kuan; Xie, Xu-Ming

    2012-10-01

    This investigation was to study the connections between polymer branch architecture of physical hydrogels and their properties. The bottle-brush-like polymer chains of poly(acrylic acid)-g-poly(ethylene glycol) methyl ether (PAA-g-mPEG) with PAA as backbones and mPEG as branch architecture were synthesized and in situ grafted from silica nanoparticles (SNs) to construct hydrogels cross-linked networks in aqueous solutions. The structural variables to be discussed included molecular weight and molar ratio of branch chains, and new aspects of the formation mechanism of physical hydrogels with branch structure in the absence of organic cross-links were present. The results indicated that the differences of polymer chain architecture could be distinguished via their different interactions that are present by gelation process and mature gel properties, such as gel strength and swelling ratio. The gelation occurred at the critical polymer concentration and molecular weight, respectively, and the inorganic/organic (SNs/PAA-g-mPEG) nanoparticles began to entangle and construct the cross-linking networks afterward. The gel-to-sol transition temperature (T(g-s)) and radii of SNs that were encapsulated by polymer chains as a function of time for chains' disentanglement were monitored according to the observation of the dissolution process, and the molecular weight between two consecutive entanglements (M(e)) was calculated thereafter. This study showed that the introduction of branch chain onto the linear backbone significantly promoted the chain interactions and increased entanglement density, which contributed to the hydrogels' network integrity and rigidity, thus illustrating greater elongation at break and tensile strength than the hydrogels formulated with linear polymer chains.

  16. Polyacrylic acid attenuates ethylene glycol induced hyperoxaluric damage and prevents crystal aggregation in vitro and in vivo.

    PubMed

    Sridharan, Badrinathan; Ganesh, Rajesh Nachiappa; Viswanathan, Pragasam

    2016-05-25

    The study explores calcium oxalate crystal inhibiting characteristic of polyacrylic acid (pAA), an anionic polymer in in vitro and in vivo. Animals were divided into 5 groups where group 1 served as control, group 2 were made hyperoxaluric by supplementing with Ethylene glycol (EG) 0.75% (v/v) for 30 days. Group 3, 4 & 5 were also given with EG and treated simultaneously with 2.5, 5 & 10 mg of pAA/kg of body weight, respectively. Urine, serum and tissue analyses along with histological studies were performed at the end of the 30 days study. In vitro crystallization was significantly inhibited by pAA and further it was supported by particle size analyses, XRD and FT-IR studies. Toxicological analyses showed that pAA was safe to use in animals at concentrations below 100 mg/kg BW. In vivo anti-urolithic study showed significant improvement in urinary lithogenic factors (calcium, oxalate, phosphate, citrate & magnesium) and renal function parameters (creatinine, urea and protein). Tissue analyses on anti-oxidant enzyme activity and lipid peroxides showed maintenance of tissue antioxidant status in the pAA supplemented rats and histological studies demonstrated the nephroprotection offered by pAA and were concurrent to the biochemical analyses. Supplementation of pAA not only reduces the crystal aggregation but also regulates the expression and localization of crystal inhibiting proteins and gene expression of inflammatory cytokines in experimental animals. In summary, pAA is a potent anti-urolithic agent in rats and we can propose that 10 mg/kg body weight is the effective dosage of pAA and this concentration can be used for further studies.

  17. Synthesis and Characterization of Silicate Ester Prodrugs and Poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) Block Copolymers for Formulation into Prodrug-Loaded Nanoparticles

    NASA Astrophysics Data System (ADS)

    Wohl, Adam Richard

    Fine control of the physical and chemical properties of customized materials is a field that is rapidly advancing. This is especially critical in pursuits to develop and optimize novel nanoparticle drug delivery. Specifically, I aim to apply chemistry concepts to test the hypothesis "Silicate ester prodrugs of paclitaxel, customized to have the proper hydrophobicity and hydrolytic lability, can be formulated with well-defined, biocompatible, amphiphilic block copolymers into nanoparticles that are effective drugs." Chapter 1 briefly describes the context and motivation of the scientific pursuits described in this thesis. In Chapter 2, a family of model silicate esters is synthesized, the hydrolysis rate of each compound is benchmarked, and trends are established based upon the steric bulk and leaving group ability of the silicate substituents. These trends are then applied to the synthesis of labile silicate ester prodrugs in Chapter 3. The bulk of this chapter focuses on the synthesis, hydrolysis, and cytotoxicity of prodrugs based on paclitaxel, a widely used chemotherapeutic agent. In Chapter 4, a new methodology for the synthesis of narrowly dispersed, "random" poly(lactic-co-glycolic acid) polymers by a constant infusion of the glycolide monomer is detailed. Using poly(ethylene glycol) as a macroinitiator, amphiphilic block copolymers were synthesized. Co-formulating a paclitaxel silicate and an amphiphilic block copolymer via flash nanoprecipitation led to highly prodrug-loaded, kinetically trapped nanoparticles. Studies to determine the structure, morphology, behavior, and efficacy of these nanoparticles are described in Chapter 5. Efforts to develop a general strategy for the selective end-functionalization of the polyether block of these amphiphilic block copolymers are discussed in Chapter 6. Examples of this strategy include functionalization of the polyether with an azide or a maleimide. Finally, Chapter 7 provides an outlook for future development of

  18. The surface grafting of graphene oxide with poly(ethylene glycol) as a reinforcement for poly(lactic acid) nanocomposite scaffolds for potential tissue engineering applications.

    PubMed

    Zhang, Chunmei; Wang, Liwei; Zhai, Tianliang; Wang, Xinchao; Dan, Yi; Turng, Lih-Sheng

    2016-01-01

    Graphene oxide (GO) was incorporated into poly(lactic acid) (PLA) as a reinforcing nanofiller to produce composite nanofibrous scaffolds using the electrospinning technique. To improve the dispersion of GO in PLA and the interfacial adhesion between the filler and matrix, GO was surface-grafted with poly(ethylene glycol) (PEG). Morphological, thermal, mechanical, and wettability properties, as well as preliminary cytocompatibility with Swiss mouse NIH 3T3 cells of PLA, PLA/GO, and PLA/GO-g-PEG electrospun nanofibers, were characterized. Results showed that the average diameter of PLA/GO-g-PEG electrospun nanofibers decreased with filler content. Both GO and GO-g-PEG improved the thermal stability of PLA, but GO-g-PEG was more effective. The water contact angle test of the nanofiber mats showed that the addition of GO in PLA did not change the surface wettability of the materials, but PLA/GO-g-PEG samples exhibited improved wettability with lower water contact angles. The tensile strength of the composite nanofiber mats was improved with the addition of GO, and it was further enhanced when GO was surface grafted with PEG. This suggested that improved interfacial adhesion between GO and PLA was achieved by grafting PEG onto the GO. The cell viability and proliferation results showed that the cytocompatibility of PLA was not compromised with the addition of GO and GO-g-PEG. With enhanced mechanical properties as well as good wettability and cytocompatibility, PLA/GO-g-PEG composite nanofibers have the potential to be used as scaffolds in tissue engineering. PMID:26409231

  19. Cisplatin Loaded Poly(L-glutamic acid)-g-Methoxy Poly(ethylene glycol) Complex Nanoparticles for Potential Cancer Therapy: Preparation, In Vitro and In Vivo Evaluation.

    PubMed

    Yu, Haiyang; Tang, Zhaohui; Li, Mingqiang; Song, Wantong; Zhang, Dawei; Zhang, Ying; Yang, Yan; Sun, Hai; Deng, Mingxiao; Chen, Xuesi

    2016-01-01

    A series of novel polypeptide-based graft copolymer poly(L-glutamic acid)-graft-methoxy poly(ethylene glycol) (PLG-g-mPEG) was synthesized through a Steglich esterification reaction of PLG with mPEG. The structure of the copolymers was confirmed by nuclear magnetic resonance spectra (NMR) and gel permeation chromatography (GPC). MTT assay demonstrated that the PLG-g-mPEGs had good cell compatibility. The unreacted carboxyl groups of the PLG-g-mPEGs were used to complex cisplatin to form polymer-metal complex nanoparticles (CDDP/PLG-g-mPEG) for cancer therapy. The average hydrodynamic radius of the CDDP/PLG-g-mPEG nanoparticles was inr the range of 14-25 nm, which was beneficial for solid tumor targeting delivery. A sustained release without initial burst was achieved for the CDDP/PLG-g-mPEG nanoparticles, indicating that the CDDP-loaded nanoparticles had great potential to suppress the drug release in blood circulation before the nanoparticles had arrived at targeting tumors. The CDDP/PLG-g-mPEG nanoparticles showed a much longer blood retention profile as compared with the free CDDP. This indicated that the CDDP-loaded nanoparticles had much more opportunity to accumulate in tumor tissue by exerting the EPR effect. In vitro tests demonstrated that the CDDP/PLG-g-mPEG nanoparticles could inhibit the proliferation of HeLa, MCF-7 and A549 cancer cells. At equal dose (4 mg kg(-1)), the CDDP/PLG-g-mPEG nanoparticles showed comparable in vivo antitumor efficacy and significantly lower systemic toxicity as compared with free cis-Diaminedichloroplatinum (cisplatin, CDDP) in MCF-7 tumor bearing mice. These suggested that the CDDP/PLG-g-mPEG nanoparticle drug delivery system had a great potential to be used for cancer therapy.

  20. Hydrogen-bonding-induced complexation of polydimethylsiloxane-graft-poly(ethylene oxide) and poly(acrylic acid)-block-polyacrylonitrile micelles in water.

    PubMed

    Hu, Aijuan; Cui, Yushuang; Wei, Xiaoling; Lu, Zaijun; Ngai, To

    2010-09-21

    Polydimethylsiloxane-graft-poly(ethylene oxide) (PDMS-g-PEO) copolymers form micelles in water with PDMS as the core and PEO as the corona. The introduction of poly(acrylic acid)-block-polyacrylonitrile (PAA-b-PAN) block copolymers in water leads to the formation of micellar complexes due to the hydrogen bonding between carboxyl groups and ether oxygens among the PAA and PEO chains in the corona of the micelles. The effects of pH, molar ratios (r) of PAA/PEO, and the standing time on the directly mixing these two micelles in water have been investigated using laser light scattering (LLS) and transmission electron microscopy (TEM). Our results showed that the complexation between PAA and PEO in the corona was greatly enhanced at a pH below 3.5. For a fixed pH value, the interactions between these two micelles in water were governed by the value of r. At r < ∼0.6, mixing the two micelles in water resulted in a large floccule because the smaller PAA-b-PAN micelles act as physical cross-links, which are absorbed onto one PDMS-g-PEO micelle and simultaneously bonded to PEO chains on the other micelles, forming bridges and causing flocculation. At ∼0.6 < r < ∼1.2, the mixing led to stable micellar complexes with a layer of PAA-b-PAN micelles absorbed onto the initial PDMS-g-PEO micelles. At r > ∼1.2, the resultant micellar complexes first remained stable, but they precipitated from solution after a long time standing.

  1. Cisplatin Loaded Poly(L-glutamic acid)-g-Methoxy Poly(ethylene glycol) Complex Nanoparticles for Potential Cancer Therapy: Preparation, In Vitro and In Vivo Evaluation.

    PubMed

    Yu, Haiyang; Tang, Zhaohui; Li, Mingqiang; Song, Wantong; Zhang, Dawei; Zhang, Ying; Yang, Yan; Sun, Hai; Deng, Mingxiao; Chen, Xuesi

    2016-01-01

    A series of novel polypeptide-based graft copolymer poly(L-glutamic acid)-graft-methoxy poly(ethylene glycol) (PLG-g-mPEG) was synthesized through a Steglich esterification reaction of PLG with mPEG. The structure of the copolymers was confirmed by nuclear magnetic resonance spectra (NMR) and gel permeation chromatography (GPC). MTT assay demonstrated that the PLG-g-mPEGs had good cell compatibility. The unreacted carboxyl groups of the PLG-g-mPEGs were used to complex cisplatin to form polymer-metal complex nanoparticles (CDDP/PLG-g-mPEG) for cancer therapy. The average hydrodynamic radius of the CDDP/PLG-g-mPEG nanoparticles was inr the range of 14-25 nm, which was beneficial for solid tumor targeting delivery. A sustained release without initial burst was achieved for the CDDP/PLG-g-mPEG nanoparticles, indicating that the CDDP-loaded nanoparticles had great potential to suppress the drug release in blood circulation before the nanoparticles had arrived at targeting tumors. The CDDP/PLG-g-mPEG nanoparticles showed a much longer blood retention profile as compared with the free CDDP. This indicated that the CDDP-loaded nanoparticles had much more opportunity to accumulate in tumor tissue by exerting the EPR effect. In vitro tests demonstrated that the CDDP/PLG-g-mPEG nanoparticles could inhibit the proliferation of HeLa, MCF-7 and A549 cancer cells. At equal dose (4 mg kg(-1)), the CDDP/PLG-g-mPEG nanoparticles showed comparable in vivo antitumor efficacy and significantly lower systemic toxicity as compared with free cis-Diaminedichloroplatinum (cisplatin, CDDP) in MCF-7 tumor bearing mice. These suggested that the CDDP/PLG-g-mPEG nanoparticle drug delivery system had a great potential to be used for cancer therapy. PMID:27301173

  2. Screening of Hyaluronic Acid-Poly(ethylene glycol) Composite Hydrogels to Support Intervertebral Disc Cell Biosynthesis using Artificial Neural Network Analysis

    PubMed Central

    Jeong, Claire G.; Francisco, Aubrey T.; Niu, Zhenbin; Mancino, Robert L; Craig, Stephen L.; Setton, Lori A.

    2014-01-01

    Hyaluronic acid (HA) poly(ethylene glycol) (PEG) composite hydrogels have been widely studied for both cell delivery and soft tissue regeneration applications. A very broad range of physical and biological properties have been engineered into HA-PEG hydrogels that may differentially affect cellular “outcomes” of survival, synthesis and metabolism. The objective of this study was to rapidly screen multiple HA-PEG composite hydrogel formulations for an effect on matrix synthesis and behaviors of nucleus pulposus (NP) and anulus fibrosus (AF) cells of the intervertebral disc (IVD). A secondary objective was to apply artificial neural network (ANN) analysis to identify relationships between HA-PEG composite hydrogel formulation parameters and biological outcome measures for each cell type of the IVD. Eight different hydrogels were developed from preparations of thiolated HA (HA-SH) and PEG vinylsulfone (PEG-VS) macromers, and used as substrates for NP and AF cell culture in vitro. Hydrogel mechanical properties ranged from 70-489 kPa depending on HA molecular weight, and measures of matrix synthesis, metabolite consumption and production, and cell morphology were obtained to study relationships to hydrogel parameters. Results showed that NP and AF cell numbers were highest upon the HA-PEG hydrogels formed from the lower molecular weight HA, with evidence of higher sGAG production also upon lower HA molecular weight composite gels. All cells formed more multi-cell clusters upon any HA-PEG composite hydrogel as compared to gelatin substrates. Formulations were clustered into neurons based largely on their HA molecular weight, with few effects of PEG molecular weight observed on any measured parameters. PMID:24859415

  3. The surface grafting of graphene oxide with poly(ethylene glycol) as a reinforcement for poly(lactic acid) nanocomposite scaffolds for potential tissue engineering applications.

    PubMed

    Zhang, Chunmei; Wang, Liwei; Zhai, Tianliang; Wang, Xinchao; Dan, Yi; Turng, Lih-Sheng

    2016-01-01

    Graphene oxide (GO) was incorporated into poly(lactic acid) (PLA) as a reinforcing nanofiller to produce composite nanofibrous scaffolds using the electrospinning technique. To improve the dispersion of GO in PLA and the interfacial adhesion between the filler and matrix, GO was surface-grafted with poly(ethylene glycol) (PEG). Morphological, thermal, mechanical, and wettability properties, as well as preliminary cytocompatibility with Swiss mouse NIH 3T3 cells of PLA, PLA/GO, and PLA/GO-g-PEG electrospun nanofibers, were characterized. Results showed that the average diameter of PLA/GO-g-PEG electrospun nanofibers decreased with filler content. Both GO and GO-g-PEG improved the thermal stability of PLA, but GO-g-PEG was more effective. The water contact angle test of the nanofiber mats showed that the addition of GO in PLA did not change the surface wettability of the materials, but PLA/GO-g-PEG samples exhibited improved wettability with lower water contact angles. The tensile strength of the composite nanofiber mats was improved with the addition of GO, and it was further enhanced when GO was surface grafted with PEG. This suggested that improved interfacial adhesion between GO and PLA was achieved by grafting PEG onto the GO. The cell viability and proliferation results showed that the cytocompatibility of PLA was not compromised with the addition of GO and GO-g-PEG. With enhanced mechanical properties as well as good wettability and cytocompatibility, PLA/GO-g-PEG composite nanofibers have the potential to be used as scaffolds in tissue engineering.

  4. Enhancing radium solubilization in soils by citrate, EDTA, and EDDS chelating amendments.

    PubMed

    Prieto, C; Lozano, J C; Blanco Rodríguez, P; Tomé, F Vera

    2013-04-15

    The effect of three chelating agents (citrate, EDTA, and EDDS) on the solubilization of radium from a granitic soil was studied systematically, considering different soil pH values, chelating agent concentrations, and leaching times. For all the chelating agents tested, the amount of radium leached proved to be strongly dependent on the pH of the substrate: only for acidic conditions did the amount of radium released increase significantly relative to the controls. Under the best conditions, the radium released from the amended soil was greater by factors of 20 in the case of citrate, 18 for EDTA, and 14 for EDDS. The greatest improvement in the release of radium was obtained for the citrate amendment at the highest concentration tested (50 mmol kg(-1)). A slightly lower amount of radium was leached with EDTA at 5 mmol kg(-1) soil, but the solubilization over time was very different from that observed with citrate or EDDS. With EDTA, a maximum in radium leaching was reached on the first day after amendment, while with citrate, the maximum was attained on the fourth day. With EDDS, radium leaching increased slightly but steadily with time (until the sixth day), but the net effect for the period tested was the lowest of the three reagents.

  5. Further studies of NO sub x control in aqueous scrubbers using ferrouster dot EDTA

    SciTech Connect

    Mendelsohn, M.H.; Livengood, C.D.; Harkness, J.B.L.

    1991-01-01

    Argonne National Laboratory has been conducting research on combined nitrogen oxides (NO{sub x}) and sulfur dioxide (SO{sub 2}) control systems. The research program has recently been focused on studies of aqueous scrubber systems enhanced with chemical additives to promote NO{sub x} removal. Tests have been conducted in a laboratory-scale scrubber system using experimental conditions selected to simulate the scrubbing of flue gas from high-sulfur coal combustion. Last year we reported the first studies performed with ferrous ethylenediaminetetraacetic acid (Fe(2){center dot}EDTA) combined with an antioxidant/reducing agent in a sodium-carbonate chemistry. This year we initiated work with Fe(2){center dot}EDTA in a lime chemistry. We found that the previously studied antioxidant/reducing agents were not as effective in a lime chemistry as they were in a sodium-carbonate chemistry. Therefore, several new antioxidant candidates were identified and screened in our aqueous scrubber system. In this paper, we compare the results obtained last year for Fe(2){center dot}EDTA alone in sodium carbonate with results obtained recently in a lime scrubber chemistry. The improvements in performance possible through the use of antioxidant/reducing agents in combination with the Fe(2){center dot}EDTA will also be discussed and used as the basis for some conclusions regarding the important chemical mechanisms. 5 refs., 6 figs.

  6. Controllable synthesis of ultrathin vanadium oxide nanobelts via an EDTA-mediated hydrothermal process

    NASA Astrophysics Data System (ADS)

    Yu-Xiang, Qin; Cheng, Liu; Wei-Wei, Xie; Meng-Yang, Cui

    2016-02-01

    Ultrathin VO2 nanobelts with rough alignment features are prepared on the induction layer-coated substrates by an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal process. EDTA acts as a chelating reagent and capping agent to facilitate the one-dimensional (1D) preferential growth of ultrathin VO2 nanobelts with high crystallinities and good uniformities. The annealed induction layer and concentration of EDTA are found to play crucial roles in the formation of aligned and ultrathin nanobelts. Variation in EDTA concentration can change the VO2 morphology of ultrathin nanobelts into that of thick nanoplates. Mild annealing of ultrathin VO2 nanobelts at 350 °C in air results in the formation of V2O5 nanobelts with a nearly unchanged ultrathin structure. The nucleation and growth mechanism involved in the formations of nanobelts and nanoplates are proposed. The ethanol gas sensing properties of the V2O5 nanobelt networks-based sensor are investigated in a temperature range from 100 °C to 300 °C over ethanol concentrations ranging from 3 ppm to 500 ppm. The results indicate that the V2O5 nanobelt network sensor exhibits high sensitivity, good reversibility, and fast response-recovery characteristics with an optimal working temperature of 250 °C. Project supported by the National Natural Science Foundation of China (Grant Nos. 61274074, 61271070, and 61574100).

  7. Simulation of the mobility of metal - EDTA complexes in groundwater: The influence of contaminant metals

    USGS Publications Warehouse

    Friedly, J.C.; Kent, D.B.; Davis, J.A.

    2002-01-01

    Reactive transport simulations were conducted to model chemical reactions between metal - EDTA (ethylenediaminetetraacetic acid) complexes during transport in a mildly acidic quartz - sand aquifer. Simulations were compared with the results of small-scale tracer tests wherein nickel-, zinc-, and calcium - EDTA complexes and free EDTA were injected into three distinct chemical zones of a plume of sewage-contaminated groundwater. One zone had a large mass of adsorbed, sewage-derived zinc; one zone had a large mass of adsorbed manganese resulting from mildly reducing conditions created bythe sewage plume; and one zone had significantly less adsorbed manganese and negligible zinc background. The chemical model assumed that the dissolution of iron(III) from metal - hydroxypolymer coatings on the aquifer sediments by the metal - EDTA complexes was kinetically restricted. All other reactions, including metal - EDTA complexation, zinc and manganese adsorption, and aluminum hydroxide dissolution were assumed to reach equilibrium on the time scale of transport; equilibrium constants were either taken from the literature or determined independently in the laboratory. A single iron(III) dissolution rate constant was used to fit the breakthrough curves observed in the zone with negligible zinc background. Simulation results agreed well with the experimental data in all three zones, which included temporal moments derived from breakthrough curves at different distances downgradient from the injections and spatial moments calculated from synoptic samplings conducted at different times. Results show that the tracer cloud was near equilibrium with respect to Fe in the sediment after 11 m of transport in the Zn-contaminated region but remained far from equilibrium in the other two zones. Sensitivity studies showed that the relative rate of iron(III) dissolution by the different metal - EDTA complexes was less important than the fact that these reactions are rate controlled. Results

  8. Outer Sphere Adsorption of Pb(II)EDTA on Goethite

    SciTech Connect

    Bargar, John R

    1999-07-16

    FTIR and EXAFS spectroscopic measurements were performed on Pb(II)EDTA adsorbed on goethite as functions of pH (4-6), Pb(II)EDTA concentration (0.11 {micro}M - 72 {micro}M), and ionic strength (16 {micro}M - 0.5M). FTIR measurements show no evidence for carboxylate-Fe(III) bonding or protonation of EDTA at Pb:EDTA = 1:1. Both FTIR and EXAFS measurements suggest that EDTA acts as a hexadentate ligand, with all four of its carboxylate and both amine groups bonded to Pb(II). No evidence was observed for inner-sphere Pb(II)-goethite bonding at Pb:EDTA = 1:1. Hence, the adsorbed complexes should have composition Pb(II)EDTA{sup 2{minus}}. Since substantial uptake of PbEDTA(II){sup 2{minus}} occurred in the samples, we infer that Pb(II)EDTA{sup 2{minus}} adsorbed as outer-sphere complexes and/or as complexes that lose part of their solvation shells and hydrogen bond directly to goethite surface sites. We propose the term ''hydration-sphere'' for the latter type of complexes because they should occupy space in the primary hydration spheres of goethite surface functional groups, and to distinguish this mode of sorption from common structural definitions of inner- and outer-sphere complexes. The similarity of Pb(II) uptake isotherms to those of other divalent metal ions complexed by EDTA suggests that they too adsorb by these mechanisms. The lack of evidence for inner-sphere EDTA-Fe(III) bonding suggests that previously proposed metal-ligand - promoted dissolution mechanisms should be modified, specifically to account for the presence of outer-sphere precursor species.

  9. Ethylene, a key factor in the regulation of seed dormancy

    PubMed Central

    Corbineau, Françoise; Xia, Qiong; Bailly, Christophe

    2014-01-01

    Ethylene is an important component of the gaseous environment, and regulates numerous plant developmental processes including seed germination and seedling establishment. Dormancy, the inability to germinate in apparently favorable conditions, has been demonstrated to be regulated by the hormonal balance between abscisic acid (ABA) and gibberellins (GAs). Ethylene plays a key role in dormancy release in numerous species, the effective concentrations allowing the germination of dormant seeds ranging between 0.1 and 200 μL L-1. Studies using inhibitors of ethylene biosynthesis or of ethylene action and analysis of mutant lines altered in genes involved in the ethylene signaling pathway (etr1, ein2, ain1, etr1, and erf1) demonstrate the involvement of ethylene in the regulation of germination and dormancy. Ethylene counteracts ABA effects through a regulation of ABA metabolism and signaling pathways. Moreover, ethylene insensitive mutants in Arabidopsis are more sensitive to ABA and the seeds are more dormant. Numerous data also show an interaction between ABA, GAs and ethylene metabolism and signaling pathways. It has been increasingly demonstrated that reactive oxygen species (ROS) may play a significant role in the regulation of seed germination interacting with hormonal signaling pathways. In the present review the responsiveness of seeds to ethylene will be described, and the key role of ethylene in the regulation of seed dormancy via a crosstalk between hormones and other signals will be discussed. PMID:25346747

  10. Ethylene, a key factor in the regulation of seed dormancy.

    PubMed

    Corbineau, Françoise; Xia, Qiong; Bailly, Christophe; El-Maarouf-Bouteau, Hayat

    2014-01-01

    Ethylene is an important component of the gaseous environment, and regulates numerous plant developmental processes including seed germination and seedling establishment. Dormancy, the inability to germinate in apparently favorable conditions, has been demonstrated to be regulated by the hormonal balance between abscisic acid (ABA) and gibberellins (GAs). Ethylene plays a key role in dormancy release in numerous species, the effective concentrations allowing the germination of dormant seeds ranging between 0.1 and 200 μL L(-1). Studies using inhibitors of ethylene biosynthesis or of ethylene action and analysis of mutant lines altered in genes involved in the ethylene signaling pathway (etr1, ein2, ain1, etr1, and erf1) demonstrate the involvement of ethylene in the regulation of germination and dormancy. Ethylene counteracts ABA effects through a regulation of ABA metabolism and signaling pathways. Moreover, ethylene insensitive mutants in Arabidopsis are more sensitive to ABA and the seeds are more dormant. Numerous data also show an interaction between ABA, GAs and ethylene metabolism and signaling pathways. It has been increasingly demonstrated that reactive oxygen species (ROS) may play a significant role in the regulation of seed germination interacting with hormonal signaling pathways. In the present review the responsiveness of seeds to ethylene will be described, and the key role of ethylene in the regulation of seed dormancy via a crosstalk between hormones and other signals will be discussed.

  11. Characterization of pH-Responsive Hydrogels of Poly(Itaconic acid-g-Ethylene Glycol) Prepared by UV-Initiated Free Radical Polymerization as Biomaterials for Oral Delivery of Bioactive Agents

    PubMed Central

    Betancourt, Tania; Pardo, Juan; Soo, Ken; Peppas, Nicholas A.

    2009-01-01

    Effective oral delivery of proteins is impeded by steep pH gradients and proteolytic enzymes in the gastrointestinal tract, as well as low absorption of the proteins into the bloodstream due to their size, charge or solubility. In the present work, pH-responsive complexation hydrogels of poly(itaconic acid) with poly(ethylene glycol) grafts were synthesized for applications in oral drug delivery. These hydrogels were expected to be in collapsed configuration at low pH due to hydrogen bonding between poly(itaconic acid) carboxyl groups and poly(ethylene glycol), and to swell with increasing pH because of charge repulsion between deprotonated carboxylic acid groups. Hydrogels were prepared by UV-initiated free radical polymerization using tetraethylene glycol as the crosslinking agent and Irgacure® 2959 as the initiator. The effect of monomer ratios, crosslinking ratio and solvent amount on the properties of the hydrogels were investigated. The composition of the hydrogels was confirmed by FTIR. Equilibrium swelling studies in the pH range of 1.2 to 7 revealed that the extent of swelling increased with increasing pH up to a pH of about 6, when no further carboxylic acid deprotonation occurred. Studies in Caco-2 colorectal carcinoma cells confirmed the cytocompatibility of these materials at concentrations of up to 5 mg/ml. PMID:19536838

  12. Role of reducing agent in extraction of arsenic and heavy metals from soils by use of EDTA.

    PubMed

    Kim, Eun Jung; Jeon, Eun-Ki; Baek, Kitae

    2016-06-01

    Although many metal-contaminated sites contain both anionic arsenic and cationic heavy metals, the current remediation technologies are not effective for the simultaneous removal of both anionic and cationic elements from the contaminated sites due to their different characteristics. In this study, the role of reducing agent in simultaneous extraction of As, Cu, Pb, and Zn from contaminated soils was investigated using EDTA. The addition of reducing agents, which includes sodium oxalate (Na2C2O4), ascorbic acid (C6H8O6) and sodium dithionite (Na2S2O4), greatly enhanced the EDTA extraction of both As and heavy metals from the contaminated soils due to the increased mobility of the metals under the reduced conditions. The extent of the enhancement of the EDTA extraction was greatly affected by the reducing conditions. Strong reducing conditions (0.1 M of dithionite) were required for the extraction of metals strongly bound to the soil, while weak reducing conditions (0.01 M of dithionite or 0.1 M of oxalate/ascorbic acid) were sufficient for extraction of metals that were relatively weakly bound to the soil. An almost 90% extraction efficiency of total metals (As, Cu, Zn, and Pb) was obtained from the contaminated soils using the combination of dithionite and EDTA. Our results clearly showed that the combination of dithionite and EDTA can effectively extract As and heavy metals simultaneously from soils under a wide range of pH conditions.

  13. Quantitative Analysis of Sulfate in Water by Indirect EDTA Titration

    ERIC Educational Resources Information Center

    Belle-Oudry, Deirdre

    2008-01-01

    The determination of sulfate concentration in water by indirect EDTA titration is an instructive experiment that is easily implemented in an analytical chemistry laboratory course. A water sample is treated with excess barium chloride to precipitate sulfate ions as BaSO[subscript 4](s). The unprecipitated barium ions are then titrated with EDTA.…

  14. Ethylene: a factor in defoliation induced by auxins.

    PubMed

    Hallaway, M; Osborne, D J

    1969-03-01

    Aerial sprays of synthetic auxins defoliate many species of tropical trees. Treatment of Euonymus japonica leaves with the n-butyl ester of 2,4-dichlorophenoxyacetic acid causes premature senescence and leaf fall and stimulates ethylene production by the blade 5-to 25-fold. Exposure to ethylene alone similarly accelerates senescence and leaf fall. Evidence indicates that the defoliant action of auxin is mediated through the enhanced amounts of ethylene in the blade. PMID:5764868

  15. Ethylene: a factor in defoliation induced by auxins.

    PubMed

    Hallaway, M; Osborne, D J

    1969-03-01

    Aerial sprays of synthetic auxins defoliate many species of tropical trees. Treatment of Euonymus japonica leaves with the n-butyl ester of 2,4-dichlorophenoxyacetic acid causes premature senescence and leaf fall and stimulates ethylene production by the blade 5-to 25-fold. Exposure to ethylene alone similarly accelerates senescence and leaf fall. Evidence indicates that the defoliant action of auxin is mediated through the enhanced amounts of ethylene in the blade.

  16. Sublethal concentrations of salicylic acid decrease the formation of reactive oxygen species but maintain an increased nitric oxide production in the root apex of the ethylene-insensitive never ripe tomato mutants.

    PubMed

    Tari, Irma; Poór, Péter; Gémes, Katalin

    2011-09-01

    The pattern of salicylic acid (SA)-induced production of reactive oxygen species (ROS) and nitric oxide (NO) were different in the apex of adventitious roots in wild-type and in the ethylene-insensitive never ripe (Nr) mutants of tomato (Solanum lycopersicum L. cv Ailsa Craig). ROS were upregulated, while NO remained at the control level in apical root tissues of wildtype plants exposed to sublethal concentrations of SA. In contrast, Nr plants expressing a defective ethylene receptor displayed a reduced level of RO S and a higher NO content in the apical root cells. In wild-type plants NO production seems to be RO S(H2O2)-dependent at cell death-inducing concentrations of SA, indicating that ROS and NO may interact to trigger oxidative cell death. In the absence of significant RO S accumulation, the increased NO production caused moderate reduction in cell viability in root apex of Nr plants exposed to 10(-3) M SA. This suggests that a functional ethylene signaling pathway is necessary for the control of ROS and NO production induced by SA.

  17. Transport of Sr2+ and SrEDTA2- in partially-saturated and heterogeneous sediments.

    PubMed

    Pace, M N; Mayes, M A; Jardine, P M; McKay, L D; Yin, X L; Mehlhorn, T L; Liu, Q; Gürleyük, H

    2007-05-14

    Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr(2+) and SrEDTA(2-). The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA(2-) complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr(2+) as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr(2+) and SrEDTA(2-) suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA(2-), MnEDTA(2-), PbEDTA(2-), and unidentified Sr and Ca complexes. Displacement of Sr(2+) through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested

  18. EDTA-dependent pseudothrombocytopenia: further insights and recommendations for prevention of a clinically threatening artifact.

    PubMed

    Lippi, Giuseppe; Plebani, Mario

    2012-08-01

    Ethylenediaminetetra-acetic acid (EDTA) is widely used as anticoagulant in laboratory medicine. EDTA-dependent pseudothrombocytopenia is a rare phenomenon (i.e., around 0.1% in the general population), which is mostly due to the presence of EDTA-dependent antiplatelet antibodies that react optimally between 0°C and 4°C, recognize the cytoadhesive receptors gpIIb-IIIa, stimulate the expression of activation antigens, trigger activation of tyrosine kinase, platelet agglutination and clumping in vitro, which finally lead to a spuriously decreased platelet count. The reliable and timely identification of this artifact is essential, since there a high chance that it may be confused with other life-threatening platelet disorders, or otherwise lead to inappropriate clinical and therapeutic decision-making. Five basic criteria should be fulfilled to raise the clinical suspicion of EDTA-dependent pseudothrombocytopenia, i.e., (i) abnormal platelet count, typically <100×10(9)/L; (ii) occurrence of thrombocytopenia in EDTA-anticoagulated samples at room temperature, but to a much lesser extent in samples collected with other anticoagulants and/or kept warmed at ~37°C; (iii) time-dependent fall of platelet count in the EDTA specimen; (iv) evidence of platelet aggregates and clumps in EDTA-anticoagulated samples with either automated cell counting or microscopic analysis; (v) lack of signs or symptoms of platelet disorders. Several remedies have been proposed, such as warming the sample to 37°C or using additives or specific formulations of anticoagulants including buffered sodium citrate, heparin, ammonium oxalate, β-hydroxyethyltheophylline, sodium fluoride, CPT (trisodium citrate, pyridoxal 5'-phosphate and Tris), antiplatelet agents, potassium azide, amikacin, kanamycin or other aminoglycosides, and calcium replacement with the simultaneous addition of calcium chloride/heparin. According to available evidences, the most suitable and practical approach so far for most

  19. The delivery of poly(lactic acid)-poly(ethylene glycol) nanoparticles loaded with non-toxic drug to overcome drug resistance for the treatment of neuroblastoma

    NASA Astrophysics Data System (ADS)

    Dhulekar, Jhilmil

    Neuroblastoma is a rare cancer of the sympathetic nervous system. A neuroblastoma tumor develops in the nerve tissue and is diagnosed in infants and children. Approximately 10.2 per million children under the age of 15 are affected in the United States and is slightly more common in boys. Neuroblastoma constitutes 6% of all childhood cancers and has a long-term survival rate of only 15%. There are approximately 700 new cases of neuroblastoma each year in the United States. With such a low rate of survival, the development of more effective treatment methods is necessary. A number of therapies are available for the treatment of these tumors; however, clinicians and their patients face the challenges of systemic side effects and drug resistance of the tumor cells. The application of nanoparticles has the potential to provide a safer and more effective method of delivery drugs to tumors. The advantage of using nanoparticles for drug delivery is the ability to specifically or passively target tumors while reducing the harmful side effects of chemotherapeutics. Drug delivery via nanoparticles can also allow for lower dosage requirements with controlled release of the drugs, which can further reduce systemic toxicity. The aim of this research was to develop a polymeric nanoparticle drug delivery system for the treatment of high-risk neuroblastoma. Nanoparticles composed of a poly(lactic acid)-poly(ethylene glycol) block copolymer were formulated to deliver a non-toxic drug in combination with Temozolomide, a commonly used chemotherapeutic drug for the treatment of neuroblastoma. The non-toxic drug acts as an inhibitor to the DNA-repair protein present in neuroblastoma cells that is responsible for inducing drug resistance in the cells, which would potentially allow for enhanced temozolomide activity. A variety of studies were completed to prove the nanoparticles' low toxicity, loading abilities, and uptake into cells. Additionally, studies were performed to determine the

  20. Ethylene prunes translation.

    PubMed

    Salehin, Mohammad; Estelle, Mark

    2015-10-22

    Ethylene regulates many aspects of plant growth and development. In the presence of ethylene, the C terminus of EIN2 (EIN2C) translocates into the nucleus and activates transcription. Li et al. and Merchante et al. show that EIN2C also regulates translation through an interaction with the 3' UTRs of transcripts. PMID:26496600

  1. Plant Life without Ethylene.

    PubMed

    Voesenek, Laurentius A C J; Pierik, Ronald; Sasidharan, Rashmi

    2015-12-01

    We propose that the ability to synthesize ethylene was selectively lost in evolution when the ancestors of fully aquatic higher plants lost their terrestrial lifestyle. We suggest that there has been negative selection on ethylene in these submerged species because it might interfere with growth in permanently deluged environments.

  2. Determination of cobalt(II)-EDTA, cobalt(III)-EDTA, and cobalt(II) in an aqueous solution

    SciTech Connect

    Ayres, D.M.; Davis, A.P.

    1996-11-01

    The determination of Co-EDTA species is critical to the understanding of radionuclide migration in the environment, as well as determining efficiencies of various complexed-Co treatment technologies. A new, simple column-oxidation separation methodology was devised to determine the fraction of uncomplexed Co(II), Co(II)-EDTA, and Co(III)-EDTA in an aqueous mixture. A Dowex 50W (H{sup +}) ion-exchange resin, and the oxidative conversion of residual Co(II)-EDTA to Co(III)-EDTA using H{sub 2}O{sub 2}, allowed the separation of species fractions. Only atomic absorption spectrophotometric measurements were required after separation of the fractions. Analysis of individual Co species separated from mixtures ranging in concentration from 3 {times} 10{sup {minus}5} to 3 {times} 10{sup {minus}3} M total Co resulted in average recoveries of 97 {plus_minus} 4%. 15 refs., 2 tabs.

  3. Effect of background region of interest and time-interval selection on glomerular filtration ratio estimation by percentage dose uptake of (99m)Tc-DTPA in comparison with (51)Cr-EDTA clearance in healthy cats.

    PubMed

    Debruyn, Katrien; Vandermeulen, Eva; Saunders, Jimmy H; Dobbeleir, André A; Ham, Hamphrey R; Peremans, Kathelijne

    2013-08-01

    Evaluation of glomerular function is a useful part of the diagnostic approach in animals suspected of having renal disease. Time-interval and background region of interest (bg ROI) selection are determining factors when calculating the glomerular filtration ratio (GFR) based on percentage uptake of (99m)technetium-labelled diethylene triamine penta-acetic acid ((99m)Tc-DTPA). Therefore, three different time intervals (60-120 s, 120-180 s, 60-180 s) and three different bg ROIs (C-shape, caudolateral, cranial + caudal) were investigated. In addition, global GFRs based on percentage dose uptake of (99m)Tc-DTPA for the different time-intervals and bg ROIs were compared with the global GFR based on (51)chromium-ethylene diaminic tetra-acetic acid ((51)Cr-EDTA) plasma clearance in nine healthy European domestic shorthair cats. Paired Student's t-tests and linear regression analysis were used to analyse the data. Different time intervals seemed to cause significant variation (P <0.01) in absolute GFR values, regardless of the choice of bg ROI. Significant differences (P <0.01) between bg ROIs were only observed in the 120-180s time interval between the C-shape and cranial + caudal bg ROI, and between the caudolateral and cranial + caudal bg ROI. The caudolateral bg ROI in the 60-180 s time interval showed the highest correlation coefficient (r = 0.882) between (99m)Tc-DTPA and (51)Cr-EDTA, although a significant difference (P <0.05) was present between both techniques. PMID:23349527

  4. Amine-based extraction recovery of Cu(II) from aqueous solutions in the presence of EDTA. Equilibrium studies

    SciTech Connect

    Juang, R.S.; Chen, Y.J.; Huang, I.P.

    1999-11-01

    The distribution ratios of Cu(II) between kerosene solutions of Aliquat 336 and water containing EDTA (ethylenediaminetetraacetic acid) are measured. Experiments were performed as a function of the pH, the concentration of Cu(II), the concentration ratio of EDTA to Cu(II), and the concentration of amine. It is shown that the distribution ratios first increase with pH and then decrease with further increase in pH up to 7.0. The effect of temperature on the extraction was studied, and the enthalpy of the extraction reaction was determined. Finally, the nonideal behavior of the organic phase is discussed.

  5. Optimizing the molarity of a EDTA washing solution for saturated-soil remediation of trace metal contaminated soils.

    PubMed

    Andrade, M D; Prasher, S O; Hendershot, W H

    2007-06-01

    Three experiments were conducted to optimize the use of ethylenediaminetetraacetic acid (EDTA) for reclaiming urban soils contaminated with trace metals. As compared to Na(2)EDTA, (NH(4))(2)EDTA extracted 60% more Zn and equivalent amounts of Cd, Cu and Pb from a sandy loam. When successively saturating and draining loamy sand columns during a washing cycle, which submerged it once with a (NH(4))(2)EDTA wash and four times with deionised water, the post-wash rinses largely contributed to the total cumulative extraction of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn. Both the washing solution and the deionised water rinses were added in a 2:5 liquid to soil (L:S) weight ratio. For equal amounts of EDTA, concentrating the washing solution and applying it and the ensuing rinses in a smaller 1:5 L:S weight ratio, instead of a 2:5 L:S weight ratio, increased the extraction of targeted Cr, Cu, Ni, Pb and Zn.

  6. Effect of EDTA Conditioning and Carbodiimide Pretreatment on the Bonding Performance of All-in-One Self-Etch Adhesives

    PubMed Central

    Singh, Shipra; Nagpal, Rajni; Tyagi, Shashi Prabha; Manuja, Naveen

    2015-01-01

    Objective. This study evaluated the effect of ethylenediaminetetraacetic acid (EDTA) conditioning and carbodiimide (EDC) pretreatment on the shear bond strength of two all-in-one self-etch adhesives to dentin. Methods. Flat coronal dentin surfaces were prepared on one hundred and sixty extracted human molars. Teeth were randomly divided into eight groups according to two different self-etch adhesives used [G-Bond and OptiBond-All-In-One] and four different surface pretreatments: (a) adhesive applied following manufacturer's instructions; (b) dentin conditioning with 24% EDTA gel prior to application of adhesive; (c) EDC pretreatment followed by application of adhesive; (d) application of EDC on EDTA conditioned dentin surface followed by application of adhesive. Composite restorations were placed in all the samples. Ten samples from each group were subjected to immediate and delayed (6-month storage in artificial saliva) shear bond strength evaluation. Data collected was subjected to statistical analysis using three-way ANOVA and post hoc Tukey's test at a significance level of p < 0.05.  Results and Conclusion. EDTA preconditioning as well as EDC pretreatment alone had no significant effect on the immediate and delayed bond strengths of either of the adhesives. However, EDC pretreatment on EDTA conditioned dentin surface resulted in preservation of resin-dentin bond strength of both adhesives with no significant fall over six months. PMID:26557850

  7. Participation of Ethylene in Two Modes of Gravistimulation of Shoots

    NASA Technical Reports Server (NTRS)

    Harrison, M.

    1985-01-01

    In order to elucidate the role of ehtylene in gravitropism, detailed time courses for ethylene production in horizontal and upright plants were measured. Tomato and pea were chosen as examples of plants which exhibit different patterns of gravitropic curvature. Tomato seedlings were placed in gas-tight lucite boxes from which air was sampled and analyzed for ethylene. During the first 2 min interval after one set of plants was turned horizontal ethylene production was double the baseline. Similarly, plants rotated 3 rpm about a vertical axis transiently doubled ethylene production when the axis was shifted 90 deg. In order to clarify the role of this 2-min burst, the effect of exogenous ethylene was studied. In peas, epicotyls were excised, equilibrated until wound ethylene had subsided to a low stable level, and ethylene production was measured in vertical and horizontal segments. As for tomatoes, excised pea epicotyls increased their rate of ethylene production during the first 2 min of gravistimulation. Also, very low concentrations of exogenous ethylene slightly enhance curvature. On the other hand, higher levels of ethylene and 1-aminocyclopropane-1-carboxylic acid (ACC) inhibit overall curvature.

  8. Rpi-blb2-Mediated Hypersensitive Cell Death Caused by Phytophthora infestans AVRblb2 Requires SGT1, but not EDS1, NDR1, Salicylic Acid-, Jasmonic Acid-, or Ethylene-Mediated Signaling.

    PubMed

    Oh, Sang-Keun; Kwon, Suk-Yoon; Choi, Doil

    2014-09-01

    Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBS-LRR) motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD). To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.

  9. ACR process for ethylene

    SciTech Connect

    Baldwin, R.L.; Kamm, G.R.

    1983-01-01

    Describes how the advanced cracking reactor process, which is ready for a logical commercial application, offers total liquids feedstock flexibility from light naphthenes through vacuum gas oils in the same production unit. Several processes are presently being developed which are aimed at maintaining olefin selectivity when cracking the heaviest feeds. Addresses the problems posed by such heavy feedstocks. The following trends favor the ACR process in the 1980s: natural gas price decontrol; limited natural gas reserves; few new domestic LPG-based ethylene plants will be built; an economic recovery will create the need for more ethylene capacity; modest increases in ''real'' crude oil prices; plentiful supplies of vacuum gas oil at prices making it an attractive ethylene feedstock; and increasing supplies of light naphtha at prices making it an attractive ethylene feedstock as well. Predicts that these factors will swing the preferred feedstocks for ethylene manufacture back to crude oil distillates before the end of the decade. Argues that in this environment, the ACR process can deliver the lowest cost ethylene in the industry. ACR has full-range feedstock flexibility, high selectivity to ethylene, and less sensitivity to feedstock costs and co-product credits.

  10. Laser Monitoring Of Phytoextraction Enhancement Of Lead Contaminated Soil Adopting EDTA And EDDS

    NASA Astrophysics Data System (ADS)

    Hassan, M.; Abdelhamied, M.; Hanafy, A. H.; Fantoni, R.; Harith, M. A.

    2011-09-01

    Removal of heavy metals (HMs) such as Pb from soil, wastewater, and air is essential for environment and human health. Phytoremediation is a well established technology based on the use of certain green plants for contaminants removal from soil, wastewater as well as air. Scented geranium, Pelargonium zonal, is a flowering plant recently used in HMs removal from contaminated soil. In the present work, EDTA (ethylenediaminetetraacetic acid) and EDDS (S, S-ethylenediaminedisuccinic acid) were used as chemical assistants providing higher Pb availability for extraction by plant roots. Lead was artificially added to the planting media, peatmoss, at different concentrations. Laser induced breakdown spectroscopy (LIBS) was used to follow up Pb relative concentrations in peatmoss as well as plant shoots, at different sampling times during the experiment period. Laser induced chlorophyll fluorescence (LICF), has been also used to evaluate chlorophyll formation and photosynthetic apparatus status in geranium plants. Such measurements were performed on geranium plants grown under various Pb levels, as well as EDTA and EDDS combinations. The combined effect of EDTA and EDDS was found to enhance Pb extraction with time. Good correlation was found between LICF results and chlorophyll (a) (Chl.a) concentrations in plant tissues extracted by chemical analysis.

  11. EDTA and HEDTA effects on Cd, Cr, and Ni uptake by Helianthus annuus.

    PubMed

    Chen, H; Cutright, T

    2001-10-01

    Phytoremediation has shown great potential as an alternative treatment for the remediation of heavy-metal-contaminated soils and groundwater. However, the lack of a clear understanding pertaining to metal uptake/translocation mechanisms, enhancement amendments, and external effects on phytoremediation has hindered its full-scale application. The objective of this research was to investigate the ability of synthetic chelators for enhancing the phytoremediation of cadmium-, chromium- and nickel-contaminated soil. Ethylenediaminetriacetic acid (EDTA) and N-(2-hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA) were applied to the soil at various dosages to elevate metal mobility. Uptake into and translocation within Helianthus annuus was determined. It was found that EDTA at a rate of 0.5 g/kg significantly increased the shoot concentrations of Cd and Ni from 34 and 15 to 115 and 117 mg/kg, respectively. The total removal efficiency for EDTA was 59 microg/plant. HEDTA at the same application rate resulted in a total metal uptake of 42 microg/plant. These research demonstrated that chelator enhancement is plant- and metal-specific and is subjective to inhibition when multiple heavy metals are present. Results also showed that chelator toxicity reduced the plant's biomass, thereby decreasing the amount of metal accumulation.

  12. Transcriptional regulation of the ethylene response factor LeERF2 in the expression of ethylene biosynthesis genes controls ethylene production in tomato and tobacco.

    PubMed

    Zhang, Zhijin; Zhang, Haiwen; Quan, Ruidan; Wang, Xue-Chen; Huang, Rongfeng

    2009-05-01

    Fine-tuning of ethylene production plays an important role in developmental processes and in plant responses to stress, but very little is known about the regulation of ethylene response factor (ERF) proteins in ethylene biosynthesis genes and ethylene production. Identifying cis-acting elements and transcription factors that play a role in this process, therefore, is important. Previously, a tomato (Solanum lycopersicum [f. sp. Lycopersicon esculentum]) ERF protein, LeERF2, an allele of TERF2, was reported to confer ethylene triple response on plants. This paper reports the transcriptional modulation of LeERF2/TERF2 in ethylene biosynthesis in tomato and tobacco (Nicotiana tabacum). Using overexpressing and antisense LeERF2/TERF2 transgenic tomato, we found that LeERF2/TERF2 is an important regulator in the expression of ethylene biosynthesis genes and the production of ethylene. Expression analysis revealed that LeERF2/TERF2 is ethylene inducible, and ethylene production stimulated by ethylene was suppressed in antisense LeERF2/TERF2 transgenic tomato, indicating LeERF2/TERF2 to be a positive regulator in the feedback loop of ethylene induction. Further research showed that LeERF2/TERF2 conservatively modulates ethylene biosynthesis in tobacco and that such regulation in tobacco is associated with the elongation of the hypocotyl and insensitivity to abscisic acid and glucose during germination and seedling development. The effects on ethylene synthesis were similar to those of another ERF protein, TERF1, because TERF1 and LeERF2/TERF2 have overlapping roles in the transcriptional regulation of ethylene biosynthesis in tobacco. Biochemical analysis showed that LeERF2/TERF2 interacted with GCC box in the promoter of NtACS3 and with dehydration-responsive element in the promoter of LeACO3, resulting in transcriptional activation of the genes for ethylene biosynthesis in tomato and tobacco, which is a novel regulatory function of ERF proteins in plant ethylene

  13. Interaction of Light and Ethylene on Stem Gravitropism

    NASA Technical Reports Server (NTRS)

    Harrison, Marcia A.

    1996-01-01

    The major objective of this study was to evaluate light-regulated ethylene production during gravitropic bending in etiolated pea stems. Previous investigations indicated that ethylene production increases after gravistimulation and is associated with the later (counter-reactive) phase of bending. Additionally, changes in the counter-reaction and locus of curvature during gravitropism are greatly influenced by red light and ethylene production. Ethylene production may be regulated by the levels of available precursor (1-aminocyclopropane-l-carboxylic acid, ACC) via its synthesis, conjugation to malonyl-ACC or glutamyl-ACC, or oxidation to ethylene. The regulation of ethylene production by quantifying ACC and conjugated ACC levels in gravistimulated pea stemswas examined. Also measured was the changes in protein and enzyme activity associated with gravitropic curvature by electrophoretic and spectrophotometric techniques. An image analysis system was used to visualize and quantify enzymatic activity and transcriptional products in gravistimulated and red-light treated etiolated pea stem tissues.

  14. Ethylene and Hormonal Cross Talk in Vegetative Growth and Development.

    PubMed

    Van de Poel, Bram; Smet, Dajo; Van Der Straeten, Dominique

    2015-09-01

    Ethylene is a gaseous plant hormone that most likely became a functional hormone during the evolution of charophyte green algae, prior to land colonization. From this ancient origin, ethylene evolved into an important growth regulator that is essential for myriad plant developmental processes. In vegetative growth, ethylene appears to have a dual role, stimulating and inhibiting growth, depending on the species, tissue, and cell type, developmental stage, hormonal status, and environmental conditions. Moreover, ethylene signaling and response are part of an intricate network in cross talk with internal and external cues. Besides being a crucial factor in the growth control of roots and shoots, ethylene can promote flowering, fruit ripening and abscission, as well as leaf and petal senescence and abscission and, hence, plays a role in virtually every phase of plant life. Last but not least, together with jasmonates, salicylate, and abscisic acid, ethylene is important in steering stress responses.

  15. Ethylene-Induced Lateral Expansion in Etiolated Pea Stems 1

    PubMed Central

    Taiz, Lincoln; Rayle, David L.; Eisinger, William

    1983-01-01

    Ethylene-induced inhibition of elongation and promotion of lateral expansion in the stems of etiolated pea (Pisum sativum L. var Alaska) seedlings is not associated with any alteration of auxin-stimulated proton extrusion. Indeed, lateral expansion in response to ethylene apparently requires an acidified wall since it is prevented by strong neutral buffers and by the ATPase inhibitor orthovanadate. Ethylene treatment reduces the capacity of live and frozen-thawed sections to extend in the longitudinal direction in response to acid. The effect of ethylene on lateral acid growth capacity is more complicated. Ethylene-treated internodes do not exhibit acid-induced lateral expansion. Ethylene-treated segments which have been frozen-thawed do show an enhanced capacity to extend in the transverse direction at acid pH, but only when the inner tissues have been removed by coring. We conclude that two of the factors which control the directionality of expansion during ethylene treatment are a decrease in the sensitivity of the walls to acid longitudinally and an increase in the sensitivity of the outer cortical parenchyma walls to acid in the transverse direction. PMID:16663230

  16. Carbohydrates Stimulate Ethylene Production in Tobacco Leaf Discs 1

    PubMed Central

    Philosoph-Hadas, Sonia; Meir, Shimon; Aharoni, Nehemia

    1985-01-01

    Galactose, sucrose, and glucose (50 millimolar) applied to tobacco leaf discs (Nicotiana tabacum L. cv `Xanthi') during a prolonged incubation (5-6 d) markedly stimulated ethylene production which, in turn, could be inhibited by aminoethoxyvinylglycine (2-amino-4-(2′-aminoethoxy)-trans-3-butenoic acid) (AVG) or Co2+ ions. These three tested sugars also stimulated the conversion of l-[3,4-14C]methionine to [14C]1-amino-cyclopropane-1-carboxylic acid (ACC) and to [14C]ethylene, thus indicating that the carbohydrates-stimulated ethylene production proceeds from methionine via the ACC pathway. Sucrose concentrations above 25 mm considerably enhanced ACC-dependent ethylene production, and this enhancement was related to the increased respiratory carbon dioxide. However, sucrose by itself could directly promote the step of ACC conversion to ethylene, since low sucrose concentrations (1-25 mm) enhanced ACC-dependent ethylene production also in the presence of 15% CO2. The data suggest that the stimulation of ethylene production by sugars in tobacco leaf discs results from enhancement of ACC formation as well as from the conversion of ACC to ethylene, when both steps could be involved in regulation of ethylene biosynthesis. PMID:16664186

  17. Deposition of Metal Oxide Films from Metal-EDTA Complexes by Flame Spray Technique

    NASA Astrophysics Data System (ADS)

    Komatsu, Keiji; Sekiya, Tetsuo; Toyama, Ayumu; Hasebe, Yasuhiro; Nakamura, Atsushi; Noguchi, Masahiro; Li, Yu; Ohshio, Shigeo; Akasaka, Hiroki; Muramatsu, Hiroyuki; Saitoh, Hidetoshi

    2014-06-01

    R2O3 (R = Y, Eu, Er) metal oxides were synthesized from metal-ethylenediaminetetraacetic acid (EDTA) complexes using a flame spray technique. As this technique enables high deposition rates, films with thickness of several tens of micrometers were obtained. Films of yttria, europia, and erbia phase were synthesized on stainless-steel substrates with reaction assistance by H2-O2 combustion gas. The oxide films consisted of the desired crystalline phase with micropores. The porosity of the films was in the range of 6-15%, varying with the metal used. These results suggest that the true density of the metal oxide obtained from metal-EDTA powder through the thermal reaction process plays an important role in achieving film with the desired porosity.

  18. Poly(anhydride-esters) Comprised Exclusively of Naturally Occurring Antimicrobials and EDTA: Antioxidant and Antibacterial Activities

    PubMed Central

    2015-01-01

    Carvacrol, thymol, and eugenol are naturally occurring phenolic compounds known to possess antimicrobial activity against a range of bacteria, as well as antioxidant activity. Biodegradable poly(anhydride-esters) composed of an ethylenediaminetetraacetic acid (EDTA) backbone and antimicrobial pendant groups (i.e., carvacrol, thymol, or eugenol) were synthesized via solution polymerization. The resulting polymers were characterized to confirm their chemical composition and understand their thermal properties and molecular weight. In vitro release studies demonstrated that polymer hydrolytic degradation was complete after 16 days, resulting in the release of free antimicrobials and EDTA. Antioxidant and antibacterial assays determined that polymer release media exhibited bioactivity similar to that of free compound, demonstrating that polymer incorporation and subsequent release had no effect on activity. These polymers completely degrade into components that are biologically relevant and have the capability to promote preservation of consumer products in the food and personal care industries via antimicrobial and antioxidant pathways. PMID:24702678

  19. Scanning electron microscopy subsequent to a combined treatment of NaOCl and EDTA in some non-collagenous calcified matrixes.

    PubMed

    Kodaka, T; Sano, T; Mori, R

    2000-01-01

    Using backscattered electron (BSE) imaging and scanning electron microscopy, subsequent to a combined treatment of sodium hypochlorite (NaOCl) and ethylenediamine tetra-acetic acid (EDTA) or only with EDTA etching, we observed some structures of non-collagenous calcified matrixes with the aim of revealing the correlation of deposition between calcification degree and organic amount. In human tooth enamel, the NaOCl-EDTA method eroded more intensively the hypocalcified prisms of enamel tufts containing a relatively large amount of EDTA-insoluble organic matter than the hypercalcified normal prismatic enamel containing a small amount of the organic matter. Afibrillar cementum, one of the non-collagenous calcified tissues similar to the enamel, has been reported to consist of organic-rich and poor incremental lamellae. The BSE imaging showed an alternation pattern of hypocalcification and hypercalcification. The hypocalcified lamellae were retained by EDTA etching, while the hypercalcified lamellae showed a resistance against the NaOCl-EDTA method. In the non-collagenous calcareous concretions of human pineal body, organic-rich and poor, and hyper- and hypocalcified incremental lamellae have been reported. The deposition pattern of calcification degree and organic amount was similar to that in afibrillar cementum, and the hypercalcified lamellae showed a resistance against the NaOCl-EDTA method. In conclusion, the high and the lower calcified regions of non-collagenous calcified matrixes contained smaller and larger amounts of EDTA-insoluble organic matter respectively. Moreover, scanning electron microscopy subsequent to the NaOCl-EDTA method corresponding to the BSE imaging clearly showed fine calcified structures compared with the BSE imaging. PMID:10791437

  20. Reasons for raising the maximum acceptable daily intake of EDTA and the benefits for iron fortification of foods for children 6-24 months of age.

    PubMed

    Wreesmann, Carel Theo Jozef

    2014-10-01

    The current maximum acceptable daily intake (ADI) of ethylenediaminetetraacetic acid (EDTA) of 1.9 mg day(-1) per kilogram bodyweight (mg day(-1)  kgbw(-1) ) limits the daily intake of iron as iron EDTA [ferric sodium EDTA; sodium iron(III) EDTA] to approximately 2-2.5 mg day(-1) for children 6-24 months of age. This limit was defined by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1973 based on data from an animal-feed study published in 1963. Other animal studies indicate that this limit can be raised to 4.4 or possibly up to 21.7 mg day(-1)  kgbw(-1) , which is 2.3-11.4 times higher than the current value. For nearly 50 years, iron EDTA has been used in France in medicinal syrup for infants 1-6 months of age. The maximum recommended dosage of this drug is 37 times higher than the maximum ADI of EDTA. No adverse health effects have been reported as a result of this medicinal consumption of iron EDTA. Raising the maximum ADI of EDTA to only 4.4 mg day(-1)  kgbw(-1) would enable iron EDTA, an iron fortificant with proven bioavailability in phytate-rich meals, to be added in adequate amounts to cereal-based meals for children 6-24 months of age, who are at risk of iron deficiency.

  1. Effect of the defoliant thidiazuron on ethylene evolution from mung bean hypocotyl segments.

    PubMed

    Suttle, J C

    1984-08-01

    The effect of the defoliant thidiazuron (N-phenyl-N'1,2,3-thiadiazol-5-ylurea) on ethylene evolution from etiolated mung bean hypocotyl segments was examined. Treatment of hypocotyl segments with concentrations of thidiazuron equal to or greater than 30 nanomolar stimulated ethylene evolution. Increased rates of ethylene evolution from thidiazuron-treated tissues could be detected within 90 minutes of treatment and persisted up to 30 hours after treatment. Radioactive methionine was readily taken up by thidiazuron-treated tissues and was converted to ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC) and an acidic conjugate of ACC. Aminoethoxyvinylglycine, aminooxyacetic acid, cobalt chloride, and alpha-aminoisobutyric acid reduced ethylene evolution from treated tissues. An increase in the endogenous content of free ACC coincided with the increase in ethylene evolution following thidiazuron treatment. Uptake and conversion of exogenous ACC to ethylene were not affected by thidiazuron treatment. No increases in the extractable activities of ACC synthase were detected following thidiazuron treatment.

  2. Ethylene by Naphta Cracking

    ERIC Educational Resources Information Center

    Wiseman, Peter

    1977-01-01

    Presents a discussion of the manufacture of ethylene by thermal cracking of hydrocarbon feedstocks that is useful for introducing the subject of industrial chemistry into a chemistry curriculum. (MLH)

  3. Satellite observations of ethylene

    NASA Astrophysics Data System (ADS)

    Dolan, W.; Payne, V.; Kulawik, S. S.; Bowman, K. W.

    2015-12-01

    Ethylene (C2H4) is a trace gas commonly associated with boreal fire plumes and the petrochemical industry. It has a short lifetime (~1-2 days) in the troposphere due to its reaction with OH. Chemical destruction of ethylene in the atmosphere leads to the production of ozone precursors such as carbon monoxide (CO) and formaldehyde. The Tropospheric Emission Spectrometer (TES) is a Fourier Transform Spectrometer aboard the Aura satellite that measures thermal infrared radiances with high spectral resolution. Trace gas products retrieved routinely from TES spectra include O3, CO, H2O, HDO, CH4, NH3, HCOOH, CH3OH, with OCS and PAN to be included in the next data release. The TES spectra also includes a wealth of untapped information about other trace gasses including ethylene. Ethylene was first observed in TES spectra by Alvarado et al. (2011), though it has yet to be developed into an operational product. Our study focuses on the detection and initial quantitative estimates of ethylene in TES special observations taken in support of the 2008 ARCTAS mission. Initial observations of HCN in the spectra may provide a way to distinguish between fire plume and petrochemical derived ethylene. Results indicate a correlation between ethylene and CO in fresh fire plumes but not in older plumes, consistent with the gas's short lifetime. The approach adopted here to detect ethylene in the TES 2008 ARCTAS special observations can easily be expanded to larger datasets, including those from other thermal infrared sounders as well as to other trace gases.

  4. Ethylene-Vapor Optrodes

    NASA Technical Reports Server (NTRS)

    Tabacco, Mary Beth; Zhou, Quan

    1993-01-01

    Porous optical fibers include sensing regions filled with reagents. Optical-fiber chemical sensors (optrodes) developed to measure concentrations of ethylene in air in enclosed artificial plant-growth environments. Such measurements needed because ethylene acts as plant-growth hormone affecting growth at concentrations less than or equal to 20 parts per billion. Optrodes small, but exhibit sensitivities comparable to those of larger instruments. Operated safely in potentially explosive atmospheres and neither cause, nor susceptible to, electrical interference at suboptical frequencies.

  5. Inspecting an ethylene pipe line

    SciTech Connect

    Ramsvig, D.M. ); Duncan, J.; Zillinger, L. )

    1991-07-01

    This paper reports on the Alberta Gas Ethylene Co. (AGEC), completion of intensive internal cleaning and inspection program on their 112-mi ethylene pipe line. AGEC operates two ethylene manufacturing facilities in central Alberta, Canada. The ethylene plants are located 12.4 mi east of Red Deer, Alta., at Joffre, and supply two customers in Joffre. The remaining ethylene is shipped by the 112-mi, 12-in. line to a storage cavern near Edmonton.

  6. Luminescent and magnetic materials with a high content of Eu(3+)-EDTA complexes.

    PubMed

    Pires, G P; Costa, I F; Brito, H F; Faustino, W M; Teotonio, E E S

    2016-07-01

    Bifunctional optical magnetic materials with a high europium content have been prepared. Chelating groups were introduced on the Fe3O4 surface with organosilanes containing ethylenediaminetetraacetic acid (EDTA) derivatives, which were previously prepared via a reaction between EDTA-dianhydride and aminoalkoxysilane agents: 3-(trimethoxysilyl)propylamine (1N), N-[3(trimethoxysilyl)propyl]ethylenediamine (2N) and N(1)-(3-trimethoxysilylpropyl)diethylenetriamine) (3N). The first coordination sphere of Ln-EDTA complexes present on the modified surfaces of Fe3O4 particles was completed by addition of β-diketonate ligands (tta: thenoyltrifluoroacetone, dbm: dibenzoylmethane, bzac: benzoylacetone and acac: acetylacetone) in order to improve their luminescence properties. The materials were characterized by powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and wavelength dispersive X-ray fluorescence (WDXRF) and Fourier-transform infrared (FT-IR) spectroscopy as well as by zeta potential measurements and luminescence spectroscopy. The hybrid materials exhibited intense red emission, which can be assigned to the 4f-4f transitions of the Eu(3+) ion, indicating an efficient intramolecular ligand-to-metal energy transfer. The experimental intensity parameters (Ω2 and Ω4), lifetimes (τ), as well as radiative (Arad) and non-radiative (Anrad) decay rates of the Eu(3+) ion were determined and discussed. The strategies used to obtain these materials may contribute to the development of several bifunctional systems for practical applications. PMID:27301580

  7. An Aqueous Thermodynamic Model for the Complexation of Nickel with EDTA Valid to high Base Concentration

    SciTech Connect

    Felmy, Andrew R.; Qafoku, Odeta

    2004-09-01

    An aqueous thermodynamic model is developed which accurately describes the effects of high base concentration on the complexation of Ni2+ by ethylenedinitrilotetraacetic acid (EDTA). The model is primarily developed from an extensive data on the solubility of Ni(OH)2(c) in the presence of EDTA and in the presence and absence of Ca2+ as the competing metal ion. The solubility data for Ni(OH)2(c) were obtained in solutions ranging in NaOH concentration from 0.01 to 11.6m, and in Ca 2+ concentrations extending to saturation with respect to portlandite, Ca(OH)2. Owing to the inert nature of the Ni-EDTA complexation reactions, solubility experiments were approached from both the oversaturation and undersaturation direction and over time frames extending to 413 days. The final aqueous thermodynamic model is based upon the equations of Pitzer, accurately predicts the observed solubilities to concentrations as high as 11.6m NaOH, and is consistent with UV-Vis spectroscopic studies of the complexes in solution.

  8. Influence of phytase, EDTA, and polyphenols on zinc absorption in adults from porridges fortified with zinc sulfate or zinc oxide.

    PubMed

    Brnić, Marica; Wegmüller, Rita; Zeder, Christophe; Senti, Gabriela; Hurrell, Richard F

    2014-09-01

    Fortification of cereal staples with zinc is recommended to combat zinc deficiency. To optimize zinc absorption, strategies are needed to overcome the inhibitory effect of phytic acid (PA) and perhaps polyphenols. Five zinc absorption studies were conducted in young adults consuming maize or sorghum porridges fortified with 2 mg zinc as zinc sulfate (ZnSO4) or zinc oxide (ZnO) and containing combinations of PA or polyphenols as potential inhibitors and EDTA and phytase as potential enhancers. Fractional absorption of zinc (FAZ) was measured by using the double isotopic tracer ratio method. Adding phytase to the maize porridge immediately before consumption or using phytase for dephytinization during meal preparation both increased FAZ by >80% (both P < 0.001). Adding Na2EDTA at an EDTA:zinc molar ratio of 1:1 increased FAZ from maize porridge fortified with ZnSO4 by 30% (P = 0.01) but had no influence at higher EDTA ratios or on absorption from ZnO. FAZ was slightly higher from ZnSO4 than from ZnO (P = 0.02). Sorghum polyphenols had no effect on FAZ from dephytinized sorghum porridges but decreased FAZ by 20% from PA-rich sorghum porridges (P < 0.02). The combined inhibitory effect of polyphenols and PA was overcome by EDTA. In conclusion, ZnSO4 was better absorbed than ZnO, phytase used to degrade PA during digestion or during food preparation substantially increased zinc absorption from zinc-fortified cereals, EDTA at a 1:1 molar ratio modestly enhanced zinc absorption from ZnSO4-fortified cereals but not ZnO-fortified cereals, and sorghum polyphenols inhibited zinc absorption in the presence, but not absence, of PA. This trial was registered at clinicaltrials.gov as NCT01210794.

  9. EDTA addition enhances bacterial respiration activities and hydrocarbon degradation in bioaugmented and non-bioaugmented oil-contaminated desert soils.

    PubMed

    Al Kharusi, Samiha; Abed, Raeid M M; Dobretsov, Sergey

    2016-03-01

    The low number and activity of hydrocarbon-degrading bacteria and the low solubility and availability of hydrocarbons hamper bioremediation of oil-contaminated soils in arid deserts, thus bioremediation treatments that circumvent these limitations are required. We tested the effect of Ethylenediaminetetraacetic acid (EDTA) addition, at different concentrations (i.e. 0.1, 1 and 10 mM), on bacterial respiration and biodegradation of Arabian light oil in bioaugmented (i.e. with the addition of exogenous alkane-degrading consortium) and non-bioaugmented oil-contaminated desert soils. Post-treatment shifts in the soils' bacterial community structure were monitored using MiSeq sequencing. Bacterial respiration, indicated by the amount of evolved CO2, was highest at 10 mM EDTA in bioaugmented and non-bioaugmented soils, reaching an amount of 2.2 ± 0.08 and 1.6 ± 0.02 mg-CO2 g(-1) after 14 days of incubation, respectively. GC-MS revealed that 91.5% of the C14-C30 alkanes were degraded after 42 days when 10 mM EDTA and the bacterial consortium were added together. MiSeq sequencing showed that 78-91% of retrieved sequences in the original soil belonged to Deinococci, Alphaproteobacteria, Gammaproteobacteia and Bacilli. The same bacterial classes were detected in the 10 mM EDTA-treated soils, however with slight differences in their relative abundances. In the bioaugmented soils, only Alcanivorax sp. MH3 and Parvibaculum sp. MH21 from the exogenous bacterial consortium could survive until the end of the experiment. We conclude that the addition of EDTA at appropriate concentrations could facilitate biodegradation processes by increasing hydrocarbon availability to microbes. The addition of exogenous oil-degrading bacteria along with EDTA could serve as an ideal solution for the decontamination of oil-contaminated desert soils.

  10. Differential expression of ethylene biosynthesis genes in drupelets and receptacle of raspberry (Rubus idaeus).

    PubMed

    Fuentes, Lida; Monsalve, Liliam; Morales-Quintana, Luis; Valdenegro, Mónika; Martínez, Juan-Pablo; Defilippi, Bruno G; González-Agüero, Mauricio

    2015-05-01

    Red Raspberry (Rubus idaeus) is traditionally classified as non-climacteric, and the role of ethylene in fruit ripening is not clear. The available information indicates that the receptacle, a modified stem that supports the drupelets, is involved in ethylene production of ripe fruits. In this study, we report receptacle-related ethylene biosynthesis during the ripening of fruits of cv. Heritage. In addition, the expression pattern of ethylene biosynthesis transcripts was evaluated during the ripening process. The major transcript levels of 1-aminocyclopropane-1-carboxylic acid synthase (RiACS1) and 1-aminocyclopropane-1-carboxylic acid oxidase (RiACO1) were concomitant with ethylene production, increased total soluble solids (TSS) and decreased titratable acidity (TA) and fruit firmness. Moreover, ethylene biosynthesis and transcript levels of RiACS1 and RiACO1 were higher in the receptacle, sustaining the receptacle's role as a source of ethylene in regulating the ripening of raspberry.

  11. Effects of Kinetin, IAA, and Gibberellin on Ethylene Production, and Their Interactions in Growth of Seedlings.

    PubMed

    Fuchs, Y; Lieberman, M

    1968-12-01

    Kinetin in concentrations of 10(-8) to 10(-4)m, stimulated ethylene production in 3 and 4-day old etiolated seedlings of Alaska pea (Pisum sativum L. var. Alaska). Seedlings of other species responded similarly. The response to kinetin depended on the age of the seedlings.Kinetin alone did not influence ethylene production in 6-day old stem sections, but it greatly increased the enhancing effect of IAA.Gibberellic acid had no effect on ethylene production by pea seedlings during the first 6 days of growth. Ethylene and gibberellic acid are antagonistic in their effects on growth of the seedlings; ethylene interfered severely with the action of gibberellic acid but did not completely suppress it.The inhibitors cycloheximide, cupferron, and N-ethylmaleimide, caused considerable inhibition of kinetin-induced ethylene production but were much less effective in the endogenous ethylene-forming system. PMID:16657004

  12. A free-standing, sheet-shaped, "hydrophobic" biomaterial containing polymeric micelles formed from poly(ethylene glycol)-poly(lactic acid) block copolymer for possible incorporation/release of "hydrophilic" compounds.

    PubMed

    Moroishi, Hitomi; Yoshida, Chikara; Murakami, Yoshihiko

    2013-02-01

    Sheet-shaped materials with a large contact area relative to the drug targeting site lead to advantages over conventional particle-shaped drug carriers and have several advantages for their biomedical applications. The present study proposes a methodology for preparing a novel sheet-shaped "hydrophobic" and biocompatible biomaterial in which polymeric micelles are uniformly dispersed for the incorporation of "hydrophilic" compounds into the sheet. The methoxy-terminated poly(ethylene glycol)-block-poly(lactic acid) block copolymer (CH(3)O-PEG-b-PLA) was successfully synthesized by means of the anionic ring-opening polymerization of both ethylene oxide and dl-lactide. CH(3)O-PEG-b-PLA was self-assembled and formed stable micelle-like w/o emulsion with a hydrophilic inner core in organic solvents. A sheet-shaped material containing a hydrophilic inner space for incorporating hydrophilic compounds was obtained by spin-coating both the micelle solution and a sheet-forming polymer. Fluorescent images of the sheet proved that polymeric micelles providing hydrophilic spaces were uniformly dispersed in the hydrophobic sheet. The facile technique presented in this paper can be a tool for fabricating sheet-shaped biomaterials that have a hydrophilic inner core and, consequently, that are suitable for the sustained release of hydrophilic compounds.

  13. Regulation of epinasty induced by 2,4-dichlorophenoxyacetic acid in pea and Arabidopsis plants.

    PubMed

    Pazmiño, D M; Rodríguez-Serrano, M; Sanz, M; Romero-Puertas, M C; Sandalio, L M

    2014-07-01

    The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) causes uncontrolled cell division and malformed growth in plants, giving rise to leaf epinasty and stem curvature. In this study, mechanisms involved in the regulation of leaf epinasty induced by 2,4-D were studied using different chemicals involved in reactive oxygen species (ROS) accumulation (diphenyleniodonium, butylated hydroxyanisole, EDTA, allopurinol), calcium channels (LaCl3), protein phosphorylation (cantharidin, wortmannin) and ethylene emission/perception (aminoethoxyvinyl glycine, AgNO3). The effect of these compounds on the epinasty induced by 2,4-D was analysed in shoots and leaf strips from pea plants. For further insight into the effect of 2,4-D, studies were also made in Arabidopsis mutants deficient in ROS production (rbohD, rbohF, xdh), ethylene (ein 3-1, ctr 1-1, etr 1-1), abscisic acid (aba 3.1), and jasmonic acid (coi 1.1, jar 1.1, opr 3) pathways. The results suggest that ROS production, mainly ·OH, is essential in the development of epinasty triggered by 2,4-D. Epinasty was also found to be regulated by Ca2+, protein phosphorylation and ethylene, although all these factors act downstream of ROS production. The use of Arabidopsis mutants appears to indicate that abscisic and jasmonic acid are not involved in regulating epinasty, although they could be involved in other symptoms induced by 2,4-D.

  14. EDTA ameliorates phytoextraction of lead and plant growth by reducing morphological and biochemical injuries in Brassica napus L. under lead stress.

    PubMed

    Kanwal, Urooj; Ali, Shafaqat; Shakoor, Muhammad Bilal; Farid, Mujahid; Hussain, Sabir; Yasmeen, Tahira; Adrees, Muhammad; Bharwana, Saima Aslam; Abbas, Farhat

    2014-01-01

    Brassica species are very effective in remediation of heavy metal contaminated sites. Lead (Pb) as a toxic pollutant causes number of morphological and biochemical variations in the plants. Synthetic chelator such as ethylenediaminetetraacetic acid (EDTA) improves the capability of plants to uptake heavy metals from polluted soil. In this regard, the role of EDTA in phytoextraction of lead, the seedlings of Brassica napus L. were grown hydroponically. Lead levels (50 and 100 μM) were supplied alone or together with 2.5 mM EDTA in the nutrient culture. After 7 weeks of stress, plants indicated that toxicity of Pb caused negative effects on plants and significantly reduced growth, biomass, chlorophyll content, gas exchange characteristics, and antioxidant enzymes activities such as superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT). Exposure to Pb induced the malondialdehyde (MDA), and hydrogen peroxide (H2O2) generation in both shoots and roots. The addition of EDTA alone or in combination with Pb significantly improved the plant growth, biomass, gas exchange characteristics, chlorophyll content, and antioxidant enzymes activities. EDTA also caused substantial improvement in Pb accumulation in Brassica plants. It can be deduced that application of EDTA significantly lessened the adverse effects of lead toxicity. Additionally, B. napus L. exhibited greater degree of tolerance against Pb toxicity and it also accumulated significant concentration of Pb from media. PMID:24854501

  15. Studies of chemical reduction of Fe(III)*EDTA in an SO{sub 2}/NO{sub x} aqueous scrubber system

    SciTech Connect

    Li, W.; Keener, T.C.; Mendelsohn, M.; Harkness, J.B.L.; Livengood, C.D.

    1996-03-01

    Ferrous*EDTA has been found to be an effective scrubbing agent for nitric oxide gas. A major process problem is oxidation of the iron to the ferric species, leading to a significant decrease in NO{sub x}-removal capability. Argonne National Laboratory discovered a class of organic compounds that, when used with ferrous*EDTA in a sodium carbonate chemistry, could maintain high levels of NO{sub x} removal. However, those antioxidant/reducing agents (A/R) are not effective in a lime-based chemistry. In recent reports, it has been found that ascorbic acid and related compounds are capable of maintaining stable NO{sub x} removals of about 50% (compared with about 15% without the agent) in a lime-based FGD chemistry with Fe(II)*EDTA. It is believed that the improved performance of Fe(II)*EDTA is due to the catalytic action of ascorbate in the Fe(III)*EDTA reduction system, where Fe(III)*EDTA is reduced by ascorbate and oxidized ascorbate is then reduced back to the ascorbate by sulfite/bisulfite anions, which come from the dissolution of SO{sub 2} in the flue gas. In the present work, the kinetics of the reduction of ferric chelate by ascorbate and reduction of oxidized ascorbate by sulfite/bisulfite anions at a typical flue-gas scrubber-system operating temperature ({approximately}55 C) have been determined.

  16. Comparative in vitro studies on disodium EDTA effect with and without Proteus mirabilis on the crystallization of carbonate apatite and struvite

    NASA Astrophysics Data System (ADS)

    Prywer, Jolanta; Olszynski, Marcin; Torzewska, Agnieszka; Mielniczek-Brzóska, Ewa

    2014-06-01

    Effect of disodium EDTA (salt of ethylenediamine tetraacetic acid) on the crystallization of struvite and carbonate apatite was studied. To evaluate such an effect we performed an experiment of struvite and carbonate apatite growth from artificial urine. The crystallization process was induced by Proteus mirabilis to mimic the real urinary tract infection, which usually leads to urinary stone formation. The results demonstrate that disodium EDTA exhibits the effect against P. mirabilis retarding the activity of urease - an enzyme produced by these microorganisms. The spectrophotometric results demonstrate that, with and without P. mirabilis, the addition of disodium EDTA increases the induction time and decreases the growth efficiency compared to the baseline (without disodium EDTA). These results are discussed from the standpoint of speciation of complexes formed in the solution of artificial urine in the presence of disodium EDTA. The size of struvite crystals was found to decrease in the presence of disodium EDTA. However, struvite crystals are larger in the presence of bacteria while the crystal morphology and habit remain unchanged.

  17. Does ethylene mediate cluster root formation under iron deficiency?

    PubMed

    Zaid, H; El Morabet, R; Diem, H G; Arahou, M

    2003-11-01

    Casuarina glauca develops proteoid (cluster) roots in response to Fe deficiency. This study set out to investigate the possible involvement of ethylene in the initiation and/or the morphogenesis of cluster roots (CR). For this purpose, the effect of Ag+ added as silver thiosulfate, an inhibitor of ethylene action has been studied in plants growing hydroponically. No CR formation was observed in these growth conditions. Inhibition of ethylene biosynthesis by aminoethoxyvinylglycine, 1- aminoisobutyric acid, aminoxyacetic acid or cobalt chloride also eliminated the positive effect of Fe deficiency on CR formation in C. glauca. CR were not formed in Fe- deficient roots in the presence of ethylene inhibitors, suggesting a role for ethylene in the morphological responses to Fe deficiency. Interestingly, treatment of Casuarina plants with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid stimulated significantly the formation of CR, even if plants are supplied with Fe. However, this stimulation did not reach the level of CR obtained in Fe-deficient plants. These results suggest that an ethylene-mediated signalling pathway is involved in CR formation process in C. glauca. PMID:12967908

  18. Crystal and molecular structure of Sr{sub 2}(Edta) . 5H{sub 2}O, Sr{sub 2}(H{sub 2}Edta)(HCO{sub 3}){sub 2} . 4H{sub 2}O, and Sr{sub 2}(H{sub 2}Edta)Cl{sub 2} . 5H{sub 2}O strontium ethylenediaminetetraacetates

    SciTech Connect

    Polyakova, I. N.; Poznyak, A. L.; Sergienko, V. S.

    2009-03-15

    Three Sr{sup 2+} compounds with the Edta{sup 4-} and H{sub 2}Edta{sup 2-} ligands-Sr{sub 2}(Edta) . 5H{sub 2}O (I), Sr{sub 2}(H{sub 2}Edta)(HCO{sub 3}){sub 2} . 4H{sub 2}O (II), and Sr{sub 2}(H{sub 2}Edta)Cl{sub 2} . 5H{sub 2}O (III)-are synthesized, and their crystal structures are studied. In I, the Sr(1) atom is coordinated by the hexadentate Edta{sup 4-} ligand following the 2N + 4O pattern and by two O atoms of the neighboring ligands, which affords the formation of zigzag chains. The Sr(2) atom forms bonds with O atoms of five water molecules and attaches itself to a chain via bonds with three O atoms of the Edta{sup 4-} ligands. The Sr(1)-O and Sr(2)-O bond lengths fall in the ranges 2.520(2)-2.656(3) and 2.527(3)-2.683(2) A, respectively. The Sr(1)-N bonds are 2.702(3) and 2.743(3) A long. In II and III, the H{sub 2}Edta{sup 2-} anions have a centrosymmetric structure with the trans configuration of the planar ethylenediamine fragment. The N atoms are blocked by acid protons. In II, the environment of the Sr atom is formed by six O atoms of three H{sub 2}Edta ligands, two O atoms of water molecules, and an O atom of the bicarbonate ion, which is disordered over two positions. In III, the environment of the Sr atom includes six O atoms of four H{sub 2}Edta{sup 2-} ligands and three O atoms of water molecules. The coordination number of the Sr atoms is equal to 8 + 1. In II and III, the main bonds fall in the ranges 2.534(3)-2.732(2) and 2.482(2)-2.746(3) A, whereas the ninth bond is elongated to 2.937(3) and 3.055(3) A, respectively. In II, all the structural elements are linked into wavy layers. The O-H-O interactions contribute to the stabilization of the layer and link neighboring layers. In III, hydrated Sr{sup 2+} cations and H{sub 2}Edta{sup -} anions form a three-dimensional [Sr{sub 2}(H{sub 2}Edta)(H{sub 2}O){sub 3}]{sub n}{sup 2n+} framework. The Cl{sup -} anions are fixed in channels of the framework by hydrogen bonds with four water molecules. In

  19. Ripening-associated ethylene biosynthesis in tomato fruit is autocatalytically and developmentally regulated

    PubMed Central

    Yokotani, Naoki; Nakano, Ryohei; Imanishi, Shunsuke; Nagata, Masayasu; Inaba, Akitsugu; Kubo, Yasutaka

    2009-01-01

    To investigate the regulatory mechanism(s) of ethylene biosynthesis in fruit, transgenic tomatoes with all known LeEIL genes suppressed were produced by RNA interference engineering. The transgenic tomato exhibited ethylene insensitivity phenotypes such as non-ripening and the lack of the triple response and petiole epinasty of seedlings even in the presence of exogenous ethylene. Transgenic fruit exhibited a low but consistent increase in ethylene production beyond 40 days after anthesis (DAA), with limited LeACS2 and LeACS4 expression. 1-Methylcyclopropene (1-MCP), a potent inhibitor of ethylene perception, failed to inhibit the limited increase in ethylene production and expression of the two 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) genes in the transgenic fruit. These results suggest that ripening-associated ethylene (system 2) in wild-type tomato fruit consists of two parts: a small part regulated by a developmental factor through the ethylene-independent expression of LeACS2 and LeACS4 and a large part regulated by an autocatalytic system due to the ethylene-dependent expression of the same genes. The results further suggest that basal ethylene (system 1) is less likely to be involved in the transition to system 2. Even if the effect of system 1 ethylene is eliminated, fruit can show a small increase in ethylene production due to unknown developmental factors. This increase would be enough for the stimulation of autocatalytic ethylene production, leading to fruit ripening. PMID:19605457

  20. Comparison of acidic and neutral PH root conditioners prior to a coronally positioned flap to treat gingival recession

    PubMed Central

    Ahmadi, Roya Shariatmadar; Awwadi, Mohammd Reza; Moatazed, Shilan; Rezaei, Fatemeh; Hajisadeghi, Samira

    2014-01-01

    Background: Localized gingival recession can be treated successfully via coronally positioned flap (CPF) and additional use of root surface demineralization agents. The purpose of this study was to evaluate the effects of additional use of ethylene diamine tetraacetic acid (EDTA) and citric acid as a root conditioner in association with CPF to cover localized buccal gingival recessions. Materials and Methods: Twenty-seven patients with 66 Miller class I buccal gingival recession ≥ 2 mm on single-rooted teeth were studied. Patients were randomly assigned: CPF with EDTA gel (test 1) and CPF with saturated citric acid (test 2) or CPF alone (control). Clinical parameters were measured at baseline and 1, 2, 3 and 6 months after surgery; assessment included recession depth (RD), clinical attachment level (CAL), probing depth (PD) and height of keratinized gingiva (HKG). SPSS version-20 was used to perform all statistical analyses. Data was reported as Mean ± SD. Age, RD, CAL, PD, and HKG before treatment and after 6 months among study groups were compared by one-way ANOVA followed by the Tukey test. The level of significance was considered to be less than 0.05. Results: At 6 months, all treatment modalities showed significant root coverage and gain in CAL. RD was reduced from 2.86 ± 0.76 mm to 0.55±0.53 mm in the EDTA group and from 2.37±0.57 mm to 1.03±0.43 mm in the acid group and from 2.37±0.54 mm to 0.85±0.49 mm in the control group. The average percentage of root coverage for the EDTA, acid, and control groups were 80.73%, 52.16%, and 64.50%, respectively. At 6 months, there was a significant difference (P < 0.05) in all parameters for the EDTA group (except HKG that did not vary among the groups). Conclusion: Root preparation with EDTA was an effective procedure to cover localized gingival recessions and significantly improved the amount of root coverage obtained. PMID:25097639

  1. Recovery and purification of ethylene

    DOEpatents

    Reyneke, Rian; Foral, Michael J.; Lee, Guang-Chung; Eng, Wayne W. Y.; Sinclair, Iain; Lodgson, Jeffery S.

    2008-10-21

    A process for the recovery and purification of ethylene and optionally propylene from a stream containing lighter and heavier components that employs an ethylene distributor column and a partially thermally coupled distributed distillation system.

  2. Gravitropism in higher plant shoots. IV - Further studies on participation of ethylene

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; White, Rosemary G.; Salisbury, Frank B.

    1986-01-01

    Various hypotheses regarding the influence of ethylene on gravitropism in higher plant shoots were experimentally tested. It was found that ethylene at 1.0 and 10.0 cu cm/cu m decreased the rate of gravitropic bending in cocklebur stems, while 0.1 cm/cu m of ethylene had little effect. Treating cocklebur plants with 1.0 mmol aminoethoxyvinylglycine (AVG, an ethylene synthesis inhibitor) delayed stem bending compared with controls, but adding 0.1 cu cm/cu m ethylene in the surrounding atmosphere partially restored the rate of bending of AVG-treated plants. Virtually all newly synthesized ethylene appeared in bottom halves of horizontal stems, where ethylene concentrations were as much as 100 times those in upright stems or in top halves of horizontal stems. Auxin applied to one side of a vertical stem caused extreme bending away from that side; gibberellic acid, kinetin, and abscisic acid were without effect.

  3. Modification of electrospun polyacrylonitrile nanofibers with EDTA for the removal of Cd and Cr ions from water effluents

    NASA Astrophysics Data System (ADS)

    Chaúque, Eutilério F. C.; Dlamini, Langelihle N.; Adelodun, Adedeji A.; Greyling, Corinne J.; Catherine Ngila, J.

    2016-04-01

    Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning technique prior to surface modification with polyethylenediaminetetraacetic acid (EDTA) using ethylenediamine (EDA) as the cross-linker. The modified nanofibers (EDTA-EDA-PAN) were subsequently applied in the wastewater treatment for the removal of Cd(II) and Cr(VI). Textural and chemical characterizations of the nanofibers were carried out by analysis of the specific surface area (Brauner Emmet and Teller (BET)) and thermogravimetric analyses, scanning electron microscopy and Fourier transform infrared spectroscopy. From the adsorption equilibrium studies with Langmuir, Freundlich and Temkin isotherm models, Freundlich was found most suitable for describing the removal mechanism of the target metals as they collect on a heterogeneously functionalized polymer surface. The EDTA-EDA-PAN nanofibers showed effective sorption affinity for both Cd(II) and Cr(VI), achieving maximum adsorption capacities of 32.68 and 66.24 mg g-1, respectively, at 298 K. In furtherance, the nanofibers were regenerated by simple washing with 2 M HCl solution. Conclusively, the EDTA-EDA-PAN nanofibers were found to be efficient for the removal of Cd(II) and Cr(VI) in water effluents.

  4. Anaerobic Biotransformation and Mobility of Pu and of Pu-EDTA

    SciTech Connect

    Xun, Luying

    2009-11-20

    The enhanced mobility of radionuclides by co-disposed chelating agent, ethylenediaminetetraacetate (EDTA), is likely to occur only under anaerobic conditions. Our extensive effort to enrich and isolate anaerobic EDTA-degrading bacteria has failed. Others has tried and also failed. To explain the lack of anaerobic biodegradation of EDTA, we proposed that EDTA has to be transported into the cells for metabolism. A failure of uptake may contribute to the lack of EDTA degradation under anaerobic conditions. We demonstrated that an aerobic EDTA-degrading bacterium strain BNC1 uses an ABC-type transporter system to uptake EDTA. The system has a periplasmic binding protein that bind EDTA and then interacts with membrane proteins to transport EDTA into the cell at the expense of ATP. The bind protein EppA binds only free EDTA with a Kd of 25 nM. The low Kd value indicates high affinity. However, the Kd value of Ni-EDTA is 2.4 x 10^(-10) nM, indicating much stronger stability. Since Ni and other trace metals are essential for anaerobic respiration, we conclude that the added EDTA sequestrates all trace metals and making anaerobic respiration impossible. Thus, the data explain the lack of anaerobic enrichment cultures for EDTA degradation. Although we did not obtain an EDTA degrading culture under anaerobic conditions, our finding may promote the use of certain metals that forms more stable metal-EDTA complexes than Pu(III)-EDTA to prevent the enhanced mobility. Further, our data explain why EDTA is the most dominant organic pollutant in surface waters, due to the lack of degradation of certain metal-EDTA complexes.

  5. Selectivity enhancement of Arsenazo(III) reagent towards heavier lanthanides using polyaminocarboxylic acids: A spectrophotometric study

    NASA Astrophysics Data System (ADS)

    Matharu, Komal; Mittal, Susheel K.; Ashok Kumar, S. K.; Sahoo, Suban K.

    2015-06-01

    A new study has been conducted to quantify lanthanide(III) ions using Arsenazo III-polyaminocarboxylic acid (PACA) system. The study disclosed two different analytically important information: (i) λmax of lanthanide-Arsenazo III complexes for lighter lanthanides like Ce(III) and Nd(III) did not shift from its original position on addition of PACA and (ii) for heavier lanthanides like Dy(III), Tm(III) and Lu(III) a new λmax at 538 nm was observed, while wavelengths at 610 nm and 654 nm were disappeared in presence of ethylenediaminetertracetic acid (EDTA) and trans-1,2-Diaminocyclohexane-N,N,N‧,N‧-tetraacetic acid (DCTA), further the intensity of peak decreased with increase in lanthanide(III) ion concentration. Effect of ethylene glycol-bis(2-aminoethylether)-N,N,N‧,N‧-tetraacetic acid (EGTA) and N-(2-hydroxyethyl) ethylenediamine-N,N‧,N‧-triacetic acid (EDTA-OH) on Arsenzo(III)-Ln(III) complex is very weak and there is no analytically importance of such interaction. Moreover, this work confirms that Nd(III) and heavy lanthanides can be successfully determined wit