Aluminum (AI) toxicity and phosphorous (P) deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively st...Aluminum (AI) toxicity and phosphorous (P) deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions (OAs; mainly malate, citrate and oxalate) to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3+ and mobilize phosphate (Pi), while OAs synthesized in the cell can internally sequester Al^3+ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.展开更多
A novel type of molecular tweezer receptors based on deoxycholic acid has been designed and synthesized and their binding properties were examined by UV-vis spectral titration. These molecular tweezers showed a high s...A novel type of molecular tweezer receptors based on deoxycholic acid has been designed and synthesized and their binding properties were examined by UV-vis spectral titration. These molecular tweezers showed a high selectivity toward F^- over Cl^-, Br^-, I^-, AcO^-, H2PO4^-.展开更多
AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free...AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.展开更多
A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, ...A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.展开更多
The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anio...The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.展开更多
The relationship between the selectivity of six drug ion-selective electrodes with anionic species of hetero-poly acid as exchange site and the structural and thermodynamical parameters of the metal ion has been inves...The relationship between the selectivity of six drug ion-selective electrodes with anionic species of hetero-poly acid as exchange site and the structural and thermodynamical parameters of the metal ion has been investigated experimentally and theoretically. The electrode selectivity is controlled mainly by the extractibility or hydrophobicity of the metal ion, but not by the ion-association-complex formation process. Linear relationship exists between the pK<sub>ij</sub> value and the structural parameter z<sup>2</sup>/(r + 0.85) and the thermodynamic parameter of hydration (△G<sub>h</sub>) of the metal ion. Better correlation is obtained for the pK<sub>ij</sub>vs. (z<sup>2</sup>/r)<sup>-k</sup> relationship.展开更多
Anion-exchange membranes 3362W and AM-203 were evaluated for facilitating the concentration of β-Naphthalenesulfonic acid by electrodialysis. The effect of concentration, temperature, electric current and time on the...Anion-exchange membranes 3362W and AM-203 were evaluated for facilitating the concentration of β-Naphthalenesulfonic acid by electrodialysis. The effect of concentration, temperature, electric current and time on the electrodialysis process were studied. Experimental results indicated that electrodialysis was an effective method for concentrating β-Naphthalenesulfonic acid at 25℃. Higher efficiencies were not obtained at high temperature. The overall current efficiency was 80%~95%.展开更多
L-Ascorbic acid (AsA) plays an important role in plants and animals. In plants, GDP-D-mannose pyrophosphorylase (GMP) is essential in the AsA biosynthetic pathway. However, little is known about the genes encoding...L-Ascorbic acid (AsA) plays an important role in plants and animals. In plants, GDP-D-mannose pyrophosphorylase (GMP) is essential in the AsA biosynthetic pathway. However, little is known about the genes encoding GMP in soybean and here we report genetic and functional analysis of the GmGMP1 (Glycine max GDP-D-mannose pyrophosphorylase 1) gene in this species. GmGMP1 encoded a GDP-mannose pyrophosphorylase and exhibited higher transcript levels in the leaf than in the root, stem, flower, and seed. Transcript of this gene was ubiquitous in the vegetative and reproductive organs, and was induced by abiotic stress and light. Increasing expression of GmGMP1 in Arabidopsis and soybean through an overexpressing approach caused pronounced enhancement of AsA content, and was implicated in lowering the superoxide anion radical content and lipid peroxidation levels in Arabidopsis, and conferring tolerance to osmotic and high salt stresses during seed germination. The present study represents the first systematic determination of soybean genes encoding GDP-mannose pyrophosphorylase and provides useful evidence for the functional involvement of GmGMP1 in control of AsA content and conferring tolerance to osmotic and salt stress.展开更多
Based on the determined affinity series of rare earth element complexes with IMDA for the anion-exchangers, purification of macroquantities of Nd 3+ from Y 3+, Sm 3+ from Ho 3+, La 3+ from Nd 3+ and ...Based on the determined affinity series of rare earth element complexes with IMDA for the anion-exchangers, purification of macroquantities of Nd 3+ from Y 3+, Sm 3+ from Ho 3+, La 3+ from Nd 3+ and La 3+ from Pr 3+ on the weakly basic gel anion-exchanger Amberlite IRA-68 was studied. Using the presented method on 1 L of Amberlite IRA-68 in the acetate form, it is possible to obtain about 240 g Nd 2O 3 purified from Y 2O 3. Great difference in affinity of La 3+ and Nd 3+ as well as Pr 3+ complexes for this anion-exchanger in the acetate form indicates the possibility of applying this process for purification of lanthanum on the increased scale. On 1 L of Amberilte IRA-68 in the acetate form it is possible to obtain about 1125 g La 2O 3 purified from Nd 2O 3. On the basis of these results it can be assumed that unique properties of polyacrylate anion-exchangers enable their application for separation of rare earth elements.展开更多
The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to th...The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to the differences of chain sections, functional groups, eic, polyacrylic acid superplasticizer could be divided into A, B, C three parts. Among them, A chain section included sulfonic acid groups, B chain section carboxyl groups, C chain section polyester. Polyacrylic acid superplasticizers with different matching of A, B, C chain sections, different length of C chain section and different molecular weights were synthesized by acrylic acid, polyethylene glycol, sodium methyl allylsulfonate; the relation between the molecular structure and perfolxnance was also studied. The expetimental results indicate that the water-reduction ratio increases obviously with the increment of the proportion of sodium methyl allylsulfonate chain section in the molecular; the slump retention increases greatly with the increment of the proportion of acrylic acid chain section; the dispersion of cement particles increases with the increment of the chain length of polyethylene glycol; when the molecular weight is in the range of 5000, the dispersion and slump retentibity increase with the increment of the average molecular weight of polymers.展开更多
During our studies on separation of rare earth complexes with aminopolycarboxylic acids on anion-exchangers, it is found that the affinity series of these elements with IMDA (Ln 3+ ∶IMDA=1∶2) for the anion-excha...During our studies on separation of rare earth complexes with aminopolycarboxylic acids on anion-exchangers, it is found that the affinity series of these elements with IMDA (Ln 3+ ∶IMDA=1∶2) for the anion-exchanger Dowex 1 in the acetate and IMDA forms is non-typical: Dy 3+ > Ho 3+ > Gd 3+ >Eu 3+ >Er 3+ >Y 3+ >Sm 3+ >Tm 3+ >Nd 3+ >Pr 3+ >>La 3+ . In the affinity series La 3+ is characterised as the lowest affinity in comparison with other rare earth elements, which indicates possibility of purification of La 3+ from all remaining lanthanides as well as Pr 3+ in the macro-micro systems by the frontal analysis technique. In the investigations strongly basic gel anion-exchangers Dowex 1×8 (type 1) and Dowex 2×8 (type 2) and strongly basic and weakly basic macroporous anion-exchangers Dowex MSA-1 and Dowex MWA 1 were used. Macroporous ion-exchangers have a sponge-like matrix which contains pores larger than molecules in size and the exchange of large ions is faster. The studies indicate that both the gel and macroporous anion-exchangers are useful for purification of La 3+ from Pr 3+ complexes with iminodiacetic acid.展开更多
A novel anionic organotin(Ⅳ) complex {[(pClCHCH)Sn(HO)(Cl)OCOCH(O)CH(O)COSn(HO)(Cl)(p-ClCHCH)]·2(HNEt)}(1) was synthesized by the reaction of di(p-chlorobenzy)tin dichloride with the D-tartaric acid in 2:1 molar...A novel anionic organotin(Ⅳ) complex {[(pClCHCH)Sn(HO)(Cl)OCOCH(O)CH(O)COSn(HO)(Cl)(p-ClCHCH)]·2(HNEt)}(1) was synthesized by the reaction of di(p-chlorobenzy)tin dichloride with the D-tartaric acid in 2:1 molar in the presence of an organic base triethylamine. The structure was characterized by elemental analysis, IR, TG, XRD and single-crystal X-ray diffraction. It crystallizes in triclinic, P1 space group, with a = 0.7067(1), b = 1.9762(3), c = 2.2383(3) nm, α = 91.544(2)°, β = 90.075(2)°, γ = 90.110(2)°, V = 3.1247(7) nm~3, Z = 3, Dc = 1.621 g/cm~3, m(Mo Kα) = 16.29 cm–1, F(000) = 1530, R = 0.0394, wR = 0.1092,(Δρ)max = 1224 and(Δρ)min = –840 e/nm~3. The stabilities, orbital energies and composition characteristics of some frontier molecular orbitals of 1 have been carefully investigated with quantum chemistry calculation. In addition, the in vitro antitumor activity suggested that 1 had stronger inhibitory activity on H460, MCF7 than on A549.展开更多
基金financially supported by the National Natural Science Foundation of China(No.U1301212)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB15030202)
文摘Aluminum (AI) toxicity and phosphorous (P) deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions (OAs; mainly malate, citrate and oxalate) to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3+ and mobilize phosphate (Pi), while OAs synthesized in the cell can internally sequester Al^3+ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.
基金We are very grateful to the National Natural Science Foundation of China(No.20272038)for the financial support.
文摘A novel type of molecular tweezer receptors based on deoxycholic acid has been designed and synthesized and their binding properties were examined by UV-vis spectral titration. These molecular tweezers showed a high selectivity toward F^- over Cl^-, Br^-, I^-, AcO^-, H2PO4^-.
文摘AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.
基金Project(2005CB623702) supported by the National Key Basic Research Program of China
文摘A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.
文摘The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.
基金Project supported by the National Natural Science Foundation of China.
文摘The relationship between the selectivity of six drug ion-selective electrodes with anionic species of hetero-poly acid as exchange site and the structural and thermodynamical parameters of the metal ion has been investigated experimentally and theoretically. The electrode selectivity is controlled mainly by the extractibility or hydrophobicity of the metal ion, but not by the ion-association-complex formation process. Linear relationship exists between the pK<sub>ij</sub> value and the structural parameter z<sup>2</sup>/(r + 0.85) and the thermodynamic parameter of hydration (△G<sub>h</sub>) of the metal ion. Better correlation is obtained for the pK<sub>ij</sub>vs. (z<sup>2</sup>/r)<sup>-k</sup> relationship.
文摘Anion-exchange membranes 3362W and AM-203 were evaluated for facilitating the concentration of β-Naphthalenesulfonic acid by electrodialysis. The effect of concentration, temperature, electric current and time on the electrodialysis process were studied. Experimental results indicated that electrodialysis was an effective method for concentrating β-Naphthalenesulfonic acid at 25℃. Higher efficiencies were not obtained at high temperature. The overall current efficiency was 80%~95%.
基金supported by the Genetically Modified Organisms Breeding Major Projects, China (2016ZX08004)the earmarked fund for China Agriculture Research System (CARS-004-PS10)the Program for Changjiang Scholars and Innovative Research Team in University, China (PCSIRT13073)
文摘L-Ascorbic acid (AsA) plays an important role in plants and animals. In plants, GDP-D-mannose pyrophosphorylase (GMP) is essential in the AsA biosynthetic pathway. However, little is known about the genes encoding GMP in soybean and here we report genetic and functional analysis of the GmGMP1 (Glycine max GDP-D-mannose pyrophosphorylase 1) gene in this species. GmGMP1 encoded a GDP-mannose pyrophosphorylase and exhibited higher transcript levels in the leaf than in the root, stem, flower, and seed. Transcript of this gene was ubiquitous in the vegetative and reproductive organs, and was induced by abiotic stress and light. Increasing expression of GmGMP1 in Arabidopsis and soybean through an overexpressing approach caused pronounced enhancement of AsA content, and was implicated in lowering the superoxide anion radical content and lipid peroxidation levels in Arabidopsis, and conferring tolerance to osmotic and high salt stresses during seed germination. The present study represents the first systematic determination of soybean genes encoding GDP-mannose pyrophosphorylase and provides useful evidence for the functional involvement of GmGMP1 in control of AsA content and conferring tolerance to osmotic and salt stress.
文摘Based on the determined affinity series of rare earth element complexes with IMDA for the anion-exchangers, purification of macroquantities of Nd 3+ from Y 3+, Sm 3+ from Ho 3+, La 3+ from Nd 3+ and La 3+ from Pr 3+ on the weakly basic gel anion-exchanger Amberlite IRA-68 was studied. Using the presented method on 1 L of Amberlite IRA-68 in the acetate form, it is possible to obtain about 240 g Nd 2O 3 purified from Y 2O 3. Great difference in affinity of La 3+ and Nd 3+ as well as Pr 3+ complexes for this anion-exchanger in the acetate form indicates the possibility of applying this process for purification of lanthanum on the increased scale. On 1 L of Amberilte IRA-68 in the acetate form it is possible to obtain about 1125 g La 2O 3 purified from Nd 2O 3. On the basis of these results it can be assumed that unique properties of polyacrylate anion-exchangers enable their application for separation of rare earth elements.
基金the Western Region Traffic Construction Technology Program of the Ministry of Communications of China(No.2007-088)
文摘The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to the differences of chain sections, functional groups, eic, polyacrylic acid superplasticizer could be divided into A, B, C three parts. Among them, A chain section included sulfonic acid groups, B chain section carboxyl groups, C chain section polyester. Polyacrylic acid superplasticizers with different matching of A, B, C chain sections, different length of C chain section and different molecular weights were synthesized by acrylic acid, polyethylene glycol, sodium methyl allylsulfonate; the relation between the molecular structure and perfolxnance was also studied. The expetimental results indicate that the water-reduction ratio increases obviously with the increment of the proportion of sodium methyl allylsulfonate chain section in the molecular; the slump retention increases greatly with the increment of the proportion of acrylic acid chain section; the dispersion of cement particles increases with the increment of the chain length of polyethylene glycol; when the molecular weight is in the range of 5000, the dispersion and slump retentibity increase with the increment of the average molecular weight of polymers.
文摘During our studies on separation of rare earth complexes with aminopolycarboxylic acids on anion-exchangers, it is found that the affinity series of these elements with IMDA (Ln 3+ ∶IMDA=1∶2) for the anion-exchanger Dowex 1 in the acetate and IMDA forms is non-typical: Dy 3+ > Ho 3+ > Gd 3+ >Eu 3+ >Er 3+ >Y 3+ >Sm 3+ >Tm 3+ >Nd 3+ >Pr 3+ >>La 3+ . In the affinity series La 3+ is characterised as the lowest affinity in comparison with other rare earth elements, which indicates possibility of purification of La 3+ from all remaining lanthanides as well as Pr 3+ in the macro-micro systems by the frontal analysis technique. In the investigations strongly basic gel anion-exchangers Dowex 1×8 (type 1) and Dowex 2×8 (type 2) and strongly basic and weakly basic macroporous anion-exchangers Dowex MSA-1 and Dowex MWA 1 were used. Macroporous ion-exchangers have a sponge-like matrix which contains pores larger than molecules in size and the exchange of large ions is faster. The studies indicate that both the gel and macroporous anion-exchangers are useful for purification of La 3+ from Pr 3+ complexes with iminodiacetic acid.
基金Supported by the Open Fund Project innovation platform of Key Laboratory of Higher Educational Institutions of Hunan Province(GN16K01)Scientific&Technological Projects of Hengyang(2016KL03)+1 种基金Aid programs for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Provincethe Key Discipline of Hunan Province,Project funding for research and innovation experiment of university students in Hunan Province
文摘A novel anionic organotin(Ⅳ) complex {[(pClCHCH)Sn(HO)(Cl)OCOCH(O)CH(O)COSn(HO)(Cl)(p-ClCHCH)]·2(HNEt)}(1) was synthesized by the reaction of di(p-chlorobenzy)tin dichloride with the D-tartaric acid in 2:1 molar in the presence of an organic base triethylamine. The structure was characterized by elemental analysis, IR, TG, XRD and single-crystal X-ray diffraction. It crystallizes in triclinic, P1 space group, with a = 0.7067(1), b = 1.9762(3), c = 2.2383(3) nm, α = 91.544(2)°, β = 90.075(2)°, γ = 90.110(2)°, V = 3.1247(7) nm~3, Z = 3, Dc = 1.621 g/cm~3, m(Mo Kα) = 16.29 cm–1, F(000) = 1530, R = 0.0394, wR = 0.1092,(Δρ)max = 1224 and(Δρ)min = –840 e/nm~3. The stabilities, orbital energies and composition characteristics of some frontier molecular orbitals of 1 have been carefully investigated with quantum chemistry calculation. In addition, the in vitro antitumor activity suggested that 1 had stronger inhibitory activity on H460, MCF7 than on A549.