[Objective] The aim of this study was to study effects of metal ions on the protease activities in digestive tissues and gland of red-white ornamental carp（Cyprinus carpio L）.[Method] Effects of four kinds of metal ...[Objective] The aim of this study was to study effects of metal ions on the protease activities in digestive tissues and gland of red-white ornamental carp（Cyprinus carpio L）.[Method] Effects of four kinds of metal ions （K＋,Na＋,Mg2＋ and Ca2＋） on protease activities in hepatopancreas,foregut,midgut,hindgut of red-white ornamental carp were studied by enzyme analysis method.[Result] Effects of four kinds of metal ions on protease activities of red-white ornamental carp were different in the range of experimental concentration from 25 mmol/L to 150 mmol/L.K＋ could promote protease activities in hepatopancreas and hindgut at different levels.Especially,K＋ had the promoting effect at low-concentration level,but the inhibitory effect at high-concentration level in midgut and the inhibitory effect in foregut.Na＋ had the promoting effect on protease activities in hepatopancreas,foregut and hindgut at different levels,but the inhibitory effect in midgut.Mg2＋ and Ca2＋ had the inhibitory effect on protease activities in intestinal and hepatopancreas at different levels.[Conclusion] This study provides basic data and theoretical foundation for researches on the digestive physiology of red-white ornamental carp or the development and optimization of compound feed.展开更多
A new extracellular κ-carrageenase, namely CgkP, 34.0 kDa in molecular weight, was purified from Pseudoalteromonas sp. QY203. CgkP showed relatively high activity at acidities ranging from pH6.0 to pH9.0 and temperat...A new extracellular κ-carrageenase, namely CgkP, 34.0 kDa in molecular weight, was purified from Pseudoalteromonas sp. QY203. CgkP showed relatively high activity at acidities ranging from pH6.0 to pH9.0 and temperatures ranging from 30℃ to 50℃ with the highest activity at 45℃ and pH7.2. Sodium chloride increased its activity markedly, and KC1 increased its activity slightly. The divalent and trivalent metal ions including Cu^2＋, Ni^2＋, Zn^2＋, Mn^2＋, Al^3＋ and Fe^3＋ significantly inhibited its activity, while Mg^2＋ did not. CgkP remained 70% of original activity after being incubated at 40℃ for 48h, and remained 80% of the activity after being incubated at 45℃ for 1 h. It exhibited endo-κ-carrageenase activity, mainly depolymerizing the κ-carrageenan into disaccharide and tetrasaccharide. CgkP was more thermostable than most of previously reported κ-carrageenases with a potential of being used in industry.展开更多
Laccases are blue copper oxidases （E.C. 1.10.3.2 benzenediol：oxygen oxidoreductase） that catalyze the one-electron oxidation of phenolics, aromatic amines and other electron-rich substrates with the concomitant red...Laccases are blue copper oxidases （E.C. 1.10.3.2 benzenediol：oxygen oxidoreductase） that catalyze the one-electron oxidation of phenolics, aromatic amines and other electron-rich substrates with the concomitant reduction of 02 to H20. They are currently seen as highly interesting industrial enzymes because of their broad substrate specificity. The Phanerochaete flavido-alba laccase is expressed and secreted as a soluble active enzyme by Aspergillus niger （rLac-LPFA）. rLac-LPFA is easily purified to homogeneity. Metal ions like HgCI2, KC12, FeSO4 and MgSO4 at a concentration of 2 mM have inhibiting effect on recombinant and native laccase, whereas, CuSO4 and MnSO4 moderately increase both enzyme activities. Two potential inhibitors （sodium azide and EDTA） inhibited enzyme activity, whereas, urea and SDS have no effect on enzyme activity. The Km and V,,ax values for recombinant laccase are 0.65 mM and 300 U/mg respectively for 2,6-DMP as substrate.展开更多
This paper studies the reaction between alkaline metal ions Li＋, Na＋ and K＋ and ASR （alkali-silica reaction） reactive aggregates to determine whether Li＋ can substitute Na＋ and K＋ that are unified in cement pa...This paper studies the reaction between alkaline metal ions Li＋, Na＋ and K＋ and ASR （alkali-silica reaction） reactive aggregates to determine whether Li＋ can substitute Na＋ and K＋ that are unified in cement paste. Reactive aggregates use meta-sandstone from eastern Taiwan and Pyrex glass. Non-reactive aggregates use siliceous sand. The results show that the dissolved amount of SiO2 is lower when the reactive aggregates are immersed in an 80 ℃1 N LiOH＇H20 solution than in NaOH and KOH solutions. The reduced amounts of OH and Li＋ in the solution are also higher than those in the NaOH and KOH solutions. These results reveal that reactive SiO2 can react with LiOH to form a reactant with low water solubility. When the powder of the cement paste is immersed in an 80 ℃ 1 N LiOH-H2O solution, the amounts of free Na＋ and K＋ in the solution are higher than those in water. The increased amount increases with the duration of immersion. The amount of Li＋ in the solution also decreases with the duration of immersion. These results reveal that Li＋ can substitute Na＋ and K＋ that are unified in cement paste, which indicates that ASR can be prevented with the existence of Li＋.展开更多
The diffusion and mass transfer, reaction, integration and growth processes of the metal ions on the activated carbon fibers (ACFs) are discussed. Based on the diffusion film theory, the diffusion and the integration ...The diffusion and mass transfer, reaction, integration and growth processes of the metal ions on the activated carbon fibers (ACFs) are discussed. Based on the diffusion film theory, the diffusion and the integration model are developed to describe the deposition processes of metal ions from the solution to ACFs in the fluidized beds. The model of heat transfer of this process is established to expound the important role-played in deposition processes by the influence of the reaction heat released at ACFs surface and the non-uniform temperature distribution caused by hydrodynamics.展开更多
Silica gel impregnated with 1% aqueous solutions of different metal cations （Li^＋, Mg^2＋, Zn^2＋, Cu^2＋, Co^2＋, Ni^2＋, Ba^2＋and Th^4＋） has been used for the analysis of nonionic and cationic surfaetants using...Silica gel impregnated with 1% aqueous solutions of different metal cations （Li^＋, Mg^2＋, Zn^2＋, Cu^2＋, Co^2＋, Ni^2＋, Ba^2＋and Th^4＋） has been used for the analysis of nonionic and cationic surfaetants using simple aqueous acetone as mobile phase system. Co^2＋ was found the most suitable impregnant for the mutual separation of nonionic surfactants （Brij-35 and Brij-57） and cationic from nonionic surfactants （tetmdecyltrimethylammonium bromide and Cween-20）. Zinc sulphate impregnation （Zn^2＋-silica gel） shows identical chromatographic behavior and these layers are useful to separate nonionic surfactant （Brij-35） from cationic surfaetant （cetylpyridinium chloride）. The mutual separation of B J-35 and B J-57 is not influenced by the presence of optical brightener in the sample.展开更多
The aim of this work was to investigate the effect of different surfactants on the removal efficiency of heavy metals in sewage sludge treated by a method combining bio-acidification with Fenton oxidation. Four surfac...The aim of this work was to investigate the effect of different surfactants on the removal efficiency of heavy metals in sewage sludge treated by a method combining bio-acidification with Fenton oxidation. Four surfactants were adopted such as anionic surfactant(sodium dodecyl benzene sulfonate, SDBS), nonionic surfactants(tween-20 and tween-60) and cationic surfactant(hexadecyl trimethyl ammonium chloride, HTAC), respectively. The indigenous sulfur-oxidizing bacteria in bio-acidification phase were enriched and cultured from fresh activated sludge obtained from a wastewater treatment plant. It is shown that different surfactants exhibited distinct effect on the removal efficiency of heavy metals from sewage sludge. The nonionic surfactants,especially tween-60, promotes the solubilization of heavy metals, while the anionic and cationic surfactants hinder the removal of heavy metals. Copper is efficiently leached. The removal efficiency of cadium is relatively lower than that of Cu due to the demand for rigorous p H value. Lead is leached with a low efficiency as the formation of low soluble Pb SO4 precipitates.展开更多
We report here our results on the investigation of the chain dynamics of poly(acrylic acid) in aqueous solution. The concentration of poly(acrylic acid) was approximately 3.8×10^(-4) mol/L, two orders of magnitud...We report here our results on the investigation of the chain dynamics of poly(acrylic acid) in aqueous solution. The concentration of poly(acrylic acid) was approximately 3.8×10^(-4) mol/L, two orders of magnitude higher than that reported in the literature. The p H value of the solution was 3.9, and the hydrogen bonds between the intrinsic and ionized carboxylic acid groups formed dynamic networks, which captured aggregation-induced emission-active molecules(a tetra-quaternary ammonium modified tetraphenylethene derivative) inside the polymer coils and induced fluorescence emission. The hydrogen bonds can be classified as intra- or intermolecular; both can be probed based on the emission change of the tetra-quaternary ammonium modified tetraphenylethene probes. The effects of different external stimuli on the polymer chain dynamics were investigated using different metal cations(including Na^+, Li^+, Zn^(2+), Ni^(2+), Ca^(2+), and Co^(2+)), different cation concentrations(1×10^(-6) to 4×10^(-4) mol/L), different poly(acrylic acid) molecular weights(5, 240, and 450 k Da), and different copolymers. The experimental results indicate that the long poly(acrylic acid) chains(high molecular weight) tend to form dense globular coils and exclude the probe molecules outside, which are robust and unsusceptible to water-soluble metal cations. However, the shorter poly(acrylic acid) chains tend to form intermolecular hydrogen bonds, which are helpful in capturing more probe molecules inside the networks, thus inducing stronger emission. Because of the dual functions of forming hydrogen bonds with carboxylic groups and acting as an acceptor of protons from the carboxylic acid group to form cationic species, copolymerization with acrylate amide [poly(acrylic acid)-co-poly(acrylamide)] can greatly affect the chain dynamics of poly(acrylic acid) segments, which is reflected by the drastically decreased emission intensity from the fluorescent probes.展开更多
文摘[Objective] The aim of this study was to study effects of metal ions on the protease activities in digestive tissues and gland of red-white ornamental carp（Cyprinus carpio L）.[Method] Effects of four kinds of metal ions （K＋,Na＋,Mg2＋ and Ca2＋） on protease activities in hepatopancreas,foregut,midgut,hindgut of red-white ornamental carp were studied by enzyme analysis method.[Result] Effects of four kinds of metal ions on protease activities of red-white ornamental carp were different in the range of experimental concentration from 25 mmol/L to 150 mmol/L.K＋ could promote protease activities in hepatopancreas and hindgut at different levels.Especially,K＋ had the promoting effect at low-concentration level,but the inhibitory effect at high-concentration level in midgut and the inhibitory effect in foregut.Na＋ had the promoting effect on protease activities in hepatopancreas,foregut and hindgut at different levels,but the inhibitory effect in midgut.Mg2＋ and Ca2＋ had the inhibitory effect on protease activities in intestinal and hepatopancreas at different levels.[Conclusion] This study provides basic data and theoretical foundation for researches on the digestive physiology of red-white ornamental carp or the development and optimization of compound feed.
基金supported by National Science Foundation of China (31000361 and 31070712)Program for Changjiang Scholars and Innovative Research Team in University (IRT0944)+1 种基金Special Fund for Marine Scientific Research in the Public Interest (201005024)the Fundamental Research Funds for the Central Universities(201013008)
文摘A new extracellular κ-carrageenase, namely CgkP, 34.0 kDa in molecular weight, was purified from Pseudoalteromonas sp. QY203. CgkP showed relatively high activity at acidities ranging from pH6.0 to pH9.0 and temperatures ranging from 30℃ to 50℃ with the highest activity at 45℃ and pH7.2. Sodium chloride increased its activity markedly, and KC1 increased its activity slightly. The divalent and trivalent metal ions including Cu^2＋, Ni^2＋, Zn^2＋, Mn^2＋, Al^3＋ and Fe^3＋ significantly inhibited its activity, while Mg^2＋ did not. CgkP remained 70% of original activity after being incubated at 40℃ for 48h, and remained 80% of the activity after being incubated at 45℃ for 1 h. It exhibited endo-κ-carrageenase activity, mainly depolymerizing the κ-carrageenan into disaccharide and tetrasaccharide. CgkP was more thermostable than most of previously reported κ-carrageenases with a potential of being used in industry.
文摘Laccases are blue copper oxidases （E.C. 1.10.3.2 benzenediol：oxygen oxidoreductase） that catalyze the one-electron oxidation of phenolics, aromatic amines and other electron-rich substrates with the concomitant reduction of 02 to H20. They are currently seen as highly interesting industrial enzymes because of their broad substrate specificity. The Phanerochaete flavido-alba laccase is expressed and secreted as a soluble active enzyme by Aspergillus niger （rLac-LPFA）. rLac-LPFA is easily purified to homogeneity. Metal ions like HgCI2, KC12, FeSO4 and MgSO4 at a concentration of 2 mM have inhibiting effect on recombinant and native laccase, whereas, CuSO4 and MnSO4 moderately increase both enzyme activities. Two potential inhibitors （sodium azide and EDTA） inhibited enzyme activity, whereas, urea and SDS have no effect on enzyme activity. The Km and V,,ax values for recombinant laccase are 0.65 mM and 300 U/mg respectively for 2,6-DMP as substrate.
文摘This paper studies the reaction between alkaline metal ions Li＋, Na＋ and K＋ and ASR （alkali-silica reaction） reactive aggregates to determine whether Li＋ can substitute Na＋ and K＋ that are unified in cement paste. Reactive aggregates use meta-sandstone from eastern Taiwan and Pyrex glass. Non-reactive aggregates use siliceous sand. The results show that the dissolved amount of SiO2 is lower when the reactive aggregates are immersed in an 80 ℃1 N LiOH＇H20 solution than in NaOH and KOH solutions. The reduced amounts of OH and Li＋ in the solution are also higher than those in the NaOH and KOH solutions. These results reveal that reactive SiO2 can react with LiOH to form a reactant with low water solubility. When the powder of the cement paste is immersed in an 80 ℃ 1 N LiOH-H2O solution, the amounts of free Na＋ and K＋ in the solution are higher than those in water. The increased amount increases with the duration of immersion. The amount of Li＋ in the solution also decreases with the duration of immersion. These results reveal that Li＋ can substitute Na＋ and K＋ that are unified in cement paste, which indicates that ASR can be prevented with the existence of Li＋.
基金NSFC (50073029) and Natural Science Foundation of Guangdong province (970513 001276)
文摘The diffusion and mass transfer, reaction, integration and growth processes of the metal ions on the activated carbon fibers (ACFs) are discussed. Based on the diffusion film theory, the diffusion and the integration model are developed to describe the deposition processes of metal ions from the solution to ACFs in the fluidized beds. The model of heat transfer of this process is established to expound the important role-played in deposition processes by the influence of the reaction heat released at ACFs surface and the non-uniform temperature distribution caused by hydrodynamics.
文摘Silica gel impregnated with 1% aqueous solutions of different metal cations （Li^＋, Mg^2＋, Zn^2＋, Cu^2＋, Co^2＋, Ni^2＋, Ba^2＋and Th^4＋） has been used for the analysis of nonionic and cationic surfaetants using simple aqueous acetone as mobile phase system. Co^2＋ was found the most suitable impregnant for the mutual separation of nonionic surfactants （Brij-35 and Brij-57） and cationic from nonionic surfactants （tetmdecyltrimethylammonium bromide and Cween-20）. Zinc sulphate impregnation （Zn^2＋-silica gel） shows identical chromatographic behavior and these layers are useful to separate nonionic surfactant （Brij-35） from cationic surfaetant （cetylpyridinium chloride）. The mutual separation of B J-35 and B J-57 is not influenced by the presence of optical brightener in the sample.
基金Project(21276069)supported by the National Natural Science Foundation of ChinaProject(CX2012B139)supported by the Hunan Province Innovation Foundation for Postgraduate,China
文摘The aim of this work was to investigate the effect of different surfactants on the removal efficiency of heavy metals in sewage sludge treated by a method combining bio-acidification with Fenton oxidation. Four surfactants were adopted such as anionic surfactant(sodium dodecyl benzene sulfonate, SDBS), nonionic surfactants(tween-20 and tween-60) and cationic surfactant(hexadecyl trimethyl ammonium chloride, HTAC), respectively. The indigenous sulfur-oxidizing bacteria in bio-acidification phase were enriched and cultured from fresh activated sludge obtained from a wastewater treatment plant. It is shown that different surfactants exhibited distinct effect on the removal efficiency of heavy metals from sewage sludge. The nonionic surfactants,especially tween-60, promotes the solubilization of heavy metals, while the anionic and cationic surfactants hinder the removal of heavy metals. Copper is efficiently leached. The removal efficiency of cadium is relatively lower than that of Cu due to the demand for rigorous p H value. Lead is leached with a low efficiency as the formation of low soluble Pb SO4 precipitates.
基金supported by the Natural Science Foundation of Zhejiang Province(2012C32007Z4110056)the National Basic Research Program of China(2013CB834704)
文摘We report here our results on the investigation of the chain dynamics of poly(acrylic acid) in aqueous solution. The concentration of poly(acrylic acid) was approximately 3.8×10^(-4) mol/L, two orders of magnitude higher than that reported in the literature. The p H value of the solution was 3.9, and the hydrogen bonds between the intrinsic and ionized carboxylic acid groups formed dynamic networks, which captured aggregation-induced emission-active molecules(a tetra-quaternary ammonium modified tetraphenylethene derivative) inside the polymer coils and induced fluorescence emission. The hydrogen bonds can be classified as intra- or intermolecular; both can be probed based on the emission change of the tetra-quaternary ammonium modified tetraphenylethene probes. The effects of different external stimuli on the polymer chain dynamics were investigated using different metal cations(including Na^+, Li^+, Zn^(2+), Ni^(2+), Ca^(2+), and Co^(2+)), different cation concentrations(1×10^(-6) to 4×10^(-4) mol/L), different poly(acrylic acid) molecular weights(5, 240, and 450 k Da), and different copolymers. The experimental results indicate that the long poly(acrylic acid) chains(high molecular weight) tend to form dense globular coils and exclude the probe molecules outside, which are robust and unsusceptible to water-soluble metal cations. However, the shorter poly(acrylic acid) chains tend to form intermolecular hydrogen bonds, which are helpful in capturing more probe molecules inside the networks, thus inducing stronger emission. Because of the dual functions of forming hydrogen bonds with carboxylic groups and acting as an acceptor of protons from the carboxylic acid group to form cationic species, copolymerization with acrylate amide [poly(acrylic acid)-co-poly(acrylamide)] can greatly affect the chain dynamics of poly(acrylic acid) segments, which is reflected by the drastically decreased emission intensity from the fluorescent probes.
