The Experts below are selected from a list of 411 Experts worldwide ranked by ideXlab platform
Gary D Rayson - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic parameters for Eu(III) binding to Datura Innoxia root material
BioMetals, 2013Co-Authors: Jessica L. Moore, Gary D RaysonAbstract:Plants offer the potential for selective removal and sequestration of toxic heavy metals from contaminated soil. Phytoextraction of metal ions involve their transport through the plant’s root system and into its shoots and leaves. This study investigates the thermodynamics of Eu(III) ion chemical interactions with Datura Innoxia plant root materials under solution conditions of pH 4.0 and 5.0. Both changes in enthalpies (∆H) and entropies (∆S) of metal binding were elucidated from isotherms collected under varied temperature conditions using regularized regression data analysis and conditional affinity spectra. ∆H values for binding to root materials at pH 4.0 and 5.0 were each calculated to be +30 kJ/mol. Values of ΔS for these same materials were found to be +170 and +153 J/mol K for solution conditions of pH 4.0 and 5.0, respectively. These results suggest binding to the root material to be entropically driven (∆S° > 0 and ΔH > 0) through possible displacement of waters of solvation.
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site specific eu iii binding affinities to a Datura Innoxia biosorbent
Journal of Hazardous Materials, 2010Co-Authors: Debbie D Serna, Jessica L. Moore, Gary D RaysonAbstract:Abstract The binding of Eu(III) to a biosorbent derived from cultured cells of the plant Datura Innoxia, have been investigated through elucidation of apparent affinity constants associated with different chemical environments present on the cell wall. Adsorption isotherms for separate types of binding sites were generated using metal ion luminescence measurements. Application of regularized regression analysis to these isotherm data for four chemically distinguishable sites revealed the presence of sites exhibiting both low (mean log Kapp = −0.3 to 0.6) and higher (mean log Kapp = 3.2–3.5) apparent affinities for pH conditions of 2.0, 4.0, and 5.0. Low affinity sites were observed for all pH conditions and attributed to non-specific binding of the metal ions to the negatively charged biomaterial. The pH-dependent higher affinity sites are ascribed to specific sites involving either an ion-exchange mechanism or formation of weak surface–metal ion complexes. These results differed significantly from a similar analysis of total metal binding isotherms that indicated mean log Kapp values of −0.5 to 0.25 (low affinity) and 5.6–6.0 (high affinity).
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simultaneous multi element detection of metal ions bound to a Datura Innoxia material
Journal of Hazardous Materials, 2003Co-Authors: Patrick A Williams, Gary D RaysonAbstract:Abstract An on-line detection scheme has been developed for the determination of metal ion affinities for binding to a plant-based substrate. This involves monitoring the effluent of a column packed with cell-wall fragments from the plant Datura Innoxia for 27 different elements simultaneously by coupling the column to an ICP emission spectrometer. Previously accepted procedures for removing native metal ions from biological materials by washing the material with a pH 2 solution were found to be insufficient for this material. Measurable amounts of Na, Mg, Al, Ca, Mn, Fe, Ni, Cr, Zn, Cd, Pb, Ba, Sr, and Si were all detected in an effluent from the introduction of 1.0 M HCl following washing the material in a pH 2 solution. Metal ion breakthrough curves for Cd 2+ , Zn 2+ , Ni 2+ , Cu 2+ , and Pb 2+ were found to exhibit an affinity order of Pb 2+ >Cu 2+ ⪢Zn 2+ ≅Cd 2+ >Ni 2+ for an equimolar mixture of these metal ions. This configuration also enabled the displacement of metal ions to be detected as the breakthrough curve for a subsequent metal ion was monitored. Comparison of Ni and Zn binding indicates a simple ion exchange model is insufficient to explain sequential binding of these metal ions.
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affinity distributions of lead ion binding to an immobilized biomaterial derived from cultured cells of Datura Innoxia
Advances in Environmental Research, 2002Co-Authors: Shan Lin, Lawrence R Drake, Gary D RaysonAbstract:Abstract Datura Innoxia biomass has been targeted as a potential sorbent for heavy metal remediation. Of interest in our laboratory are the binding mechanisms responsible for metal uptake. In this study, the binding behavior of Pb(II) to immobilized Datura Innoxia biomaterial was investigated under different chemical conditions, such as ionic strength, the presence of calcium, and pH. Regularized regression analysis was employed to derive the corresponding affinity distributions. Two classes of binding sites were determined, having mean affinity of approximately 200 and 105 M−1, depending on solution conditions. Variations in apparent affinity distributions with ionic strength and pH suggest the low-affinity sites involve sulfonates and carboxylates in an ion exchange process. The high-affinity sites are proposed to result from the coordination of carboxylates to Pb2+ ions.
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solid state 113cd nmr studies of metal binding to a Datura Innoxia biomaterial
Advances in Environmental Research, 2000Co-Authors: Hongying Xia, Gary D RaysonAbstract:Abstract The use of both slurry and solid-state 113 Cd NMR has been applied to the investigation of the chemical moieties involved in cadmium ion binding to a biosorbent. This material was derived from fragments of cell walls cultured from the plant Datura Innoxia . Comparison of the −14-ppm chemical shift of the bound metal ion with that of model ligands directly demonstrated the involvement of carboxylate-containing binding sites. The application of solid-state cross-polarization magic angle spinning techniques to the metal-bound material yielded a broad resonance. This was interpreted as indicative of the presence of a distribution of chemically similar sites.
Eric Gontier - One of the best experts on this subject based on the ideXlab platform.
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permeabilization of Datura Innoxia hairy roots for release of stored tropane alkaloids
Planta Medica, 1995Co-Authors: Michele Boitelconti, Eric Gontier, Jeanclaude Laberche, Corinne Ducrocq, B S SangwannorreelAbstract:The effects of tween 20 as permeabilizing agent on tropane alkaloids from Datura Innoxia Mill, hairy roots have been studied. For various tween 20 concentrations both hyoscyamine and scopolamine accumulated in the culture medium. Plant material viability could be preserved after a 24 hours-2% tween 20 concentration treatment. The time-course study of alkaloid release showed that the maximum of excretion occurred after a 20 hour contact with tween 20. At that time, a concentration of hyoscyamine superior to 25 mg/l was detected in the medium.
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Effects of calcium, alginate, and calcium-alginate immobilization on growth and tropane alkaloid levels of a stable suspension cell line of Datura Innoxia Mill.
Plant cell reports, 1994Co-Authors: Eric Gontier, B. S. Sangwan, J. N. BarbotinAbstract:A stabilized two-year old suspension of a Datura Innoxia cell line, producing small amounts of tropane alkaloids (scopolamine and hyoscyamine) was used in this study. Calcium alginate immobilization has been shown to be able to increase secondary metabolite (i. e. alkaloid) production. The effects of calcium and ungellified alginate were both beneficial for tropane alkaloid synthesis; a 10mM calcium chloride supply gave the best results, with a 10-fold yield increase.
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tropane alkaloid levels in the leaves of micropropagated Datura Innoxia plants
Planta Medica, 1993Co-Authors: Eric Gontier, J. N. Barbotin, M A Fliniaux, B S SangwannorrelAbstract:Three androgenic Datura Innoxia Mill. (Solanaceae) plants which had been characterised in regard to their tropane alkaloid levels were micropropagated through axillary buds. The alkaloid contents in the leaves of more than 300 micropropagated plants were investigated by ELISA and HPLC, after one and two culture cycles and compared to those of one of seedlings obtained from the same original line from which the androgenic plants had been produced. The plant with the higher alkaloid level yielded the population with the most alkaloids. After a second cycle of micropropagation, all the populations contained more alkaloids than those they had been derived from. All the micropropagated plant populations contained higher levels of alkaloids than plants grown from seeds.
J. N. Barbotin - One of the best experts on this subject based on the ideXlab platform.
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kinetic study of littorine rearrangement in Datura Innoxia hairy roots by 13c nmr spectroscopy
Journal of Natural Products, 2002Co-Authors: Arnaud Lanoue, J. N. Barbotin, Michele Boitelconti, Jeanclaude Laberche, Jeancharles Portais, Philippe Christen, B S SangwannorreelAbstract:The kinetics of tropane alkaloid biosynthesis, particularly the isomerization of littorine into hyoscyamine, were studied by analyzing the kinetics of carbon-13 (13C) in metabolites of Datura Innoxia hairy root cultures fed with labeled tropoyl moiety precursors. Both littorine and hyoscyamine were the major alkaloids accumulated, while scopolamine was never detected. Feeding root cultures with (RS)-phenyl[1,3-13C2]lactic acid led to 13C spin−spin coupling detected on C-1‘ and C-2‘ of the hyoscyamine skeleton, which validated the intramolecular rearrangement of littorine into hyoscyamine. Label from phenyl[1-13C]alanine or (RS)-phenyl[1,3-13C2]lactic acid was incorporated at higher levels in littorine than in hyoscyamine. Initially, the apparent hyoscyamine biosynthesized rate (vapphyo = 0.9 μmol 13C·flask-1·d-1) was lower than littorine formation (vapplitto = 1.8 μmol 13C·flask-1·d-1), suggesting that the isomerization reaction could be rate limiting. The results obtained for the kinetics of littorine bi...
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Effects of calcium, alginate, and calcium-alginate immobilization on growth and tropane alkaloid levels of a stable suspension cell line of Datura Innoxia Mill.
Plant cell reports, 1994Co-Authors: Eric Gontier, B. S. Sangwan, J. N. BarbotinAbstract:A stabilized two-year old suspension of a Datura Innoxia cell line, producing small amounts of tropane alkaloids (scopolamine and hyoscyamine) was used in this study. Calcium alginate immobilization has been shown to be able to increase secondary metabolite (i. e. alkaloid) production. The effects of calcium and ungellified alginate were both beneficial for tropane alkaloid synthesis; a 10mM calcium chloride supply gave the best results, with a 10-fold yield increase.
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tropane alkaloid levels in the leaves of micropropagated Datura Innoxia plants
Planta Medica, 1993Co-Authors: Eric Gontier, J. N. Barbotin, M A Fliniaux, B S SangwannorrelAbstract:Three androgenic Datura Innoxia Mill. (Solanaceae) plants which had been characterised in regard to their tropane alkaloid levels were micropropagated through axillary buds. The alkaloid contents in the leaves of more than 300 micropropagated plants were investigated by ELISA and HPLC, after one and two culture cycles and compared to those of one of seedlings obtained from the same original line from which the androgenic plants had been produced. The plant with the higher alkaloid level yielded the population with the most alkaloids. After a second cycle of micropropagation, all the populations contained more alkaloids than those they had been derived from. All the micropropagated plant populations contained higher levels of alkaloids than plants grown from seeds.
B S Sangwannorrel - One of the best experts on this subject based on the ideXlab platform.
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tropane alkaloid levels in the leaves of micropropagated Datura Innoxia plants
Planta Medica, 1993Co-Authors: Eric Gontier, J. N. Barbotin, M A Fliniaux, B S SangwannorrelAbstract:Three androgenic Datura Innoxia Mill. (Solanaceae) plants which had been characterised in regard to their tropane alkaloid levels were micropropagated through axillary buds. The alkaloid contents in the leaves of more than 300 micropropagated plants were investigated by ELISA and HPLC, after one and two culture cycles and compared to those of one of seedlings obtained from the same original line from which the androgenic plants had been produced. The plant with the higher alkaloid level yielded the population with the most alkaloids. After a second cycle of micropropagation, all the populations contained more alkaloids than those they had been derived from. All the micropropagated plant populations contained higher levels of alkaloids than plants grown from seeds.
Liliane Jean - One of the best experts on this subject based on the ideXlab platform.
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effect of citric acid and edta on chromium and nickel uptake and translocation by Datura Innoxia
Environmental Pollution, 2008Co-Authors: Liliane Jean, François Bordas, Cecile Gautiermoussard, Philippe Vernay, Adnane Hitmi, Jean-claude BollingerAbstract:Abstract EDTA and citric acid were tested to solubilize metals and enhance their uptake by Datura Innoxia , chosen because of its ability to accumulate and tolerate metals. Two application modes were used on an industrial soil contaminated mainly by Cr and Ni. The results showed that citric acid was the most effective at increasing the uptake of Cr and EDTA for Ni. These results are consistent with the effectiveness of both chelants in solubilizing metals from the soil. The translocation factor (TF) of Ni was 1.6- and 6.7-fold higher than the control, respectively, for one and two applications of 1 mmol kg −1 EDTA. After two applications of 5 and 10 mmol kg −1 citric acid, the TF of Cr increased 2- and 3.5-fold relative to the control. Whatever the concentration, the application of EDTA modified the plant physiology significantly. For citric acid this was only observed with the highest dose (10 mmol kg −1 ).
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mobilisation du chrome et du nickel a partir de sols contamines en presence de complexants transfert et accumulation de ces metaux chez Datura Innoxia
2007Co-Authors: Liliane JeanAbstract:La contamination des sols par des polluants metalliques issus de l’activite industrielle constitue un probleme environnemental majeur. La presente etude porte sur l’un de ces sols, l’objectif etant d’etudier l’influence de reactifs complexants sur la mobilisation du chrome et du nickel afin d’ameliorer leur extraction par Datura Innoxia. L’etude a d’abord ete realisee sur un sol artificiellement contamine constituant un systeme d’etude simplifiee, avant d’etre etendue au sol contamine par l’activite industrielle. L’EDTA et l’acide citrique sont les complexants les plus efficaces pour mobiliser, respectivement le nickel et le chrome. La mobilisation se fait par : reaction de complexation, reaction de competition et dissolution des phases porteuses du sol. Applique sur le sol, en presence de Datura Innoxia, l’EDTA ameliore l’accumulation du nickel tandis que l’acide citrique ameliore celle du chrome. L’evaluation du lessivage des metaux montre que l’utilisation des complexant doit se faire de facon controlee afin d’eviter un depart massif des metaux vers les systemes aquatiques.
