Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu2+ at different pH values were studied in a water/alcohol two-phase system containing Cu2+ and N-n-（...Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu2+ at different pH values were studied in a water/alcohol two-phase system containing Cu2+ and N-n-（dodecyl-L-proline（A）.） The influences of the solvent sort, the pH value, the concentrations of Cu2+ and chiral ligand on the partition coefficient（K） and separation factor（α） were discussed. The experimental results show that the A formed has more stable ternary complex with D-mandelic acid enantiomer than with L-mandelic acid enantiomer. There is an important influence of the pH value on K and α. When the pH values are less than 3.5, the formation of binary complexes is thermodynamically unfavourable. K and α become maximum when pH values are above 3.5 and the molar ratio of the chiral ligand to Cu2+ is 2∶1.展开更多
Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial ...Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial acid producing metabolisms,is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes.The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions.Several alkaliphilic acid producing bacteria were isolated in this study.One strain was selected for its superior growth pattern and acid metabolism(termed EEEL02).Based on the phylogenetic analysis,this strain was identified as Bacillus thuringiensis.The optimized fermentation conditions were as follows:pH 10;NaCl concentration 5%;temperature 25℃;EEEL02 preferred glucose and peptone as carbon and nitrogen sources,respectively.Based on optimal fermentation conditions,EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test.Acetic acid,propionic acid and CO2(g)were the major acid metabolites of fermentation,suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism.This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue.展开更多
Eleven acid mine drainage （AMD） samples were obtained from southeast of China for the analysis of the microbial communities diversity, and the relationship with geochemical variables and spatial distance by using a ...Eleven acid mine drainage （AMD） samples were obtained from southeast of China for the analysis of the microbial communities diversity, and the relationship with geochemical variables and spatial distance by using a culture-independent 16S rDNA gene phylogenetic analysis approach and multivariate analysis respectively. The principle component analysis （PCA） of geochemical variables shows that eleven AMDs can be clustered into two groups, relative high and low metal rich （RHMR and RLMR） AMDs. Total 1691 clone sequences are obtained and the detrended correspondence analysis （DCA） of operational taxonomic units （OTUs） shows that, ~,-Proteobacteria, Acidobacteria, Actinobacteria, Cyanobacteria, Firmicutes and Nitrospirae are dominant species in RHMR AMDs. In contrast, a-Proteobacteria, fl-Proteobacteria, Planctomycetes and Bacteriodetes are dominant species in RLMR AMD. Results also show that high-abundance putative iron-oxidizing and only putative sulfur-oxidizing microorganisms are found in RHMR AMD. Multivariate analysis shows that both geochemical variables （r=0.429 3, P=-0.037 7） and spatial distance （r=0.321 3, P=-0.018 1） are significantly positively correlated with microbial community and pH, Mg, Fe, S, Cu and Ca are key geochemistry factors in shaping microbial community. Variance partitioning analysis shows that geochemical variables and spatial distance can explain most （92%） of the variation.展开更多
【目的】研究桃仁的抗血栓功效与成分,为桃仁预防血栓形成提供理论依据。【方法】分别用体积分数70%的乙醇和去离子水进行提取,不同色谱柱进行分离,利用大鼠的动静脉旁路血栓模型和体外抗血小板聚集试验并结合分子对接分析,筛选出桃仁...【目的】研究桃仁的抗血栓功效与成分,为桃仁预防血栓形成提供理论依据。【方法】分别用体积分数70%的乙醇和去离子水进行提取,不同色谱柱进行分离,利用大鼠的动静脉旁路血栓模型和体外抗血小板聚集试验并结合分子对接分析,筛选出桃仁抗血栓活性成分,并利用核磁共振(nuclear magnetic resonance,NMR)技术鉴定其结构。【结果】桃仁水提物经MCI柱层析得到的体积分数10%乙醇洗脱物可显著降低大鼠的血栓质量(P<0.05),再经ODS柱层析分离,纯化得到5个单体化合物,分别为扁桃酸-β-D-吡喃葡萄糖苷(化合物1)、1-β-D-葡萄糖苷亚苯基-2-β-D-葡萄糖苷酸(化合物2)、3(-3-吲哚基)丁酸(化合物3)、α-羟基丙酸(化合物4)和dl-扁桃酸(化合物5)。体外测试结果表明,化合物1、2、5均可显著抑制因二磷酸腺苷(adenosine diphosphate,ADP)诱导引起的血小板聚集(P<0.05),其中化合物5的作用最强,抑制率达到48.67%。【结论】该研究证实了dl-扁桃酸为桃仁抗血栓功效的主要活性成分。展开更多
基金Project(20376085) supported by the National Natural Science Foundation of China
文摘Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu2+ at different pH values were studied in a water/alcohol two-phase system containing Cu2+ and N-n-（dodecyl-L-proline（A）.） The influences of the solvent sort, the pH value, the concentrations of Cu2+ and chiral ligand on the partition coefficient（K） and separation factor（α） were discussed. The experimental results show that the A formed has more stable ternary complex with D-mandelic acid enantiomer than with L-mandelic acid enantiomer. There is an important influence of the pH value on K and α. When the pH values are less than 3.5, the formation of binary complexes is thermodynamically unfavourable. K and α become maximum when pH values are above 3.5 and the molar ratio of the chiral ligand to Cu2+ is 2∶1.
基金Projects(41877511,41842020)supported by the National Natural Science Foundation of ChinaProject(502221703)supported by the Innovative Project of Independent Exploration of Central South University,China
文摘Bauxite residue deposit area(BRDA)is a typical abandoned mining wasteland representing extreme hostile environment with increased alkalinity.Microbially-driven neutralization of bauxite residue,based on the microbial acid producing metabolisms,is a novel strategy for achieving rapid pH neutralization and thus improving its environmental outcomes.The hypothesis was that these extreme conditions promote microbial communities which are capable of novel ecologically relevant functions.Several alkaliphilic acid producing bacteria were isolated in this study.One strain was selected for its superior growth pattern and acid metabolism(termed EEEL02).Based on the phylogenetic analysis,this strain was identified as Bacillus thuringiensis.The optimized fermentation conditions were as follows:pH 10;NaCl concentration 5%;temperature 25℃;EEEL02 preferred glucose and peptone as carbon and nitrogen sources,respectively.Based on optimal fermentation conditions,EEEL02 induced a significant pH reduction from 10.26 to 5.62 in 5-day incubation test.Acetic acid,propionic acid and CO2(g)were the major acid metabolites of fermentation,suggesting that the pH reduction in bauxite residue may be caused by acid neutralization derived from microbial metabolism.This finding provided the basis of a novel strategy for achieving rapid pH neutralization of bauxite residue.
基金Project(2010CB630901) supported by the National Basic Research Program of ChinaProject(50621063) supported by Creative Research Group of China+2 种基金Projects(51104189, 50321402, 50774102) supported by the National Natural Science Foundation of ChinaProject (1343-77341) supported by the Graduate Education Innovative Program of Central South University, ChinaProject(DOE-ER64125) supported by the Department of Energy, Office of Science under the Environmental Remediation Science Program of USA
文摘Eleven acid mine drainage （AMD） samples were obtained from southeast of China for the analysis of the microbial communities diversity, and the relationship with geochemical variables and spatial distance by using a culture-independent 16S rDNA gene phylogenetic analysis approach and multivariate analysis respectively. The principle component analysis （PCA） of geochemical variables shows that eleven AMDs can be clustered into two groups, relative high and low metal rich （RHMR and RLMR） AMDs. Total 1691 clone sequences are obtained and the detrended correspondence analysis （DCA） of operational taxonomic units （OTUs） shows that, ~,-Proteobacteria, Acidobacteria, Actinobacteria, Cyanobacteria, Firmicutes and Nitrospirae are dominant species in RHMR AMDs. In contrast, a-Proteobacteria, fl-Proteobacteria, Planctomycetes and Bacteriodetes are dominant species in RLMR AMD. Results also show that high-abundance putative iron-oxidizing and only putative sulfur-oxidizing microorganisms are found in RHMR AMD. Multivariate analysis shows that both geochemical variables （r=0.429 3, P=-0.037 7） and spatial distance （r=0.321 3, P=-0.018 1） are significantly positively correlated with microbial community and pH, Mg, Fe, S, Cu and Ca are key geochemistry factors in shaping microbial community. Variance partitioning analysis shows that geochemical variables and spatial distance can explain most （92%） of the variation.
文摘【目的】研究桃仁的抗血栓功效与成分,为桃仁预防血栓形成提供理论依据。【方法】分别用体积分数70%的乙醇和去离子水进行提取,不同色谱柱进行分离,利用大鼠的动静脉旁路血栓模型和体外抗血小板聚集试验并结合分子对接分析,筛选出桃仁抗血栓活性成分,并利用核磁共振(nuclear magnetic resonance,NMR)技术鉴定其结构。【结果】桃仁水提物经MCI柱层析得到的体积分数10%乙醇洗脱物可显著降低大鼠的血栓质量(P<0.05),再经ODS柱层析分离,纯化得到5个单体化合物,分别为扁桃酸-β-D-吡喃葡萄糖苷(化合物1)、1-β-D-葡萄糖苷亚苯基-2-β-D-葡萄糖苷酸(化合物2)、3(-3-吲哚基)丁酸(化合物3)、α-羟基丙酸(化合物4)和dl-扁桃酸(化合物5)。体外测试结果表明,化合物1、2、5均可显著抑制因二磷酸腺苷(adenosine diphosphate,ADP)诱导引起的血小板聚集(P<0.05),其中化合物5的作用最强,抑制率达到48.67%。【结论】该研究证实了dl-扁桃酸为桃仁抗血栓功效的主要活性成分。
