Base de dados : MEDLINE
Pesquisa : G02.300 [Categoria DeCS]
Referências encontradas : 266735 [refinar]
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[PMID]:29367490
[Au] Autor:Asakawa T; Takano Y; Ohta A; Asakawa H
[Ad] Endereço:School of Chemistry, College of Science and Engineering, Kanazawa University.
[Ti] Título:Aggregation and pH Responsive Behavior of Thioester Surfactants and Formation of Disulfide Linkages in Aqueous Solutions.
[So] Source:J Oleo Sci;67(2):199-206, 2018 Feb 01.
[Is] ISSN:1347-3352
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:pH responsive surfactants, [C H N(CH ) (CH ) SCOCH ]Br (C nSAc, n = 4, 11, 12), were prepared, and their properties in aqueous solution were examined. The critical micelle concentration (cmc) and critical vesicle concentration (cvc) were determined based on changes in conductivity, as well as by fluorescence measurements, and light scattering methods. A significant increase in the light scattering intensities of the C nSAc (n=11, 12) systems suggested that the growth of aggregates was accompanied by considerable counterion binding with increasing surfactant concentration. The diameter of C 11SAc, recorded by the dynamic light scattering measurements, was about 9.6 ±1.0 nm, which was slightly smaller than that for didodecyldimethylammonium bromide (DDAB) vesicles. The thioester group was easily hydrolyzed upon the addition of NaOH, while it was hardly hydrolyzed with the addition of HCl. The time course of alkaline hydrolysis was examined by the conductivity measurements and high-performance liquid chromatography analysis. [C H N(CH ) (CH ) SS(CH ) N(CH ) C H ]2Br (2C 11SS) was generated in the C 11SAc alkaline solution because of air oxidation. The C 11SAc alkaline solution gradually became an opaque blue color with increasing light scattering at 346 nm, indicating the remarkable growth of vesicles. The chemical structure of 2C 11SS was consistent with that of a disulfide linked double tailed surfactant, similar to DDAB. The disulfide linkage between the double tailed surfactants will contribute to the stabilization and growth of vesicles.
[Mh] Termos MeSH primário: Ésteres/química
Tensoativos/química
Água/química
[Mh] Termos MeSH secundário: Dissulfetos/química
Difusão Dinâmica da Luz
Concentração de Íons de Hidrogênio
Hidrólise
Micelas
Oxirredução
Compostos de Amônio Quaternário/química
Soluções
Tensão Superficial
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Disulfides); 0 (Esters); 0 (Micelles); 0 (Quaternary Ammonium Compounds); 0 (Solutions); 0 (Surface-Active Agents); 059QF0KO0R (Water); 13146-86-6 (didodecyldimethylammonium)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180126
[St] Status:MEDLINE
[do] DOI:10.5650/jos.ess17192


  2 / 266735 MEDLINE  
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[PMID]:29367487
[Au] Autor:Lin Y; Xie X; Yuan B; Fu J; Liu L; Tian H; Chen T; He D
[Ad] Endereço:College of Food Science and Engineering, Wuhan polytechnic University.
[Ti] Título:Optimization of Enzymatic Cell Disruption for Improving Lipid Extraction from Schizochytrium sp. through Response Surface Methodology.
[So] Source:J Oleo Sci;67(2):215-224, 2018 Feb 01.
[Is] ISSN:1347-3352
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:This study is aimed to explore the optimal conditions of cell disruption in the extraction algae oil process, using alkaline protease to disrupt cell of Schizochytrium sp. to extract oil in this paper. The effects of enzymatic lysis temperature, enzymatic lysis time, enzyme dosage and pH value on oil yield and DHA yield were studied. Through the combination of single factor test and response surface design, the optimal cell disruption conditions were screened out. The fatty acid composition of algal oil was analyzed by gas chromatography-massspectrometry (GC-MS). The results showed that when the conditions were: enzymatic lysis temperature 55°C, enzymatic lysis time 9 h, enzyme dosage 3% of biomass and pH 8,oil yield and DHA yield reached the highest 14.52 g/L and 7.12 g/L, respectively. When the strains were cultured in 50 L fermentor, oil yield reached 26.27 g/L and DHA yield reached 12.89 g/L. They were 1.81 times higher than that in shake-flask cultivation. The optimization experiment provides the basis for the industrial production of Schizochytrium sp.
[Mh] Termos MeSH primário: Proteínas de Bactérias
Endopeptidases
Extração Líquido-Líquido/métodos
Óleos/isolamento & purificação
Estramenópilas/química
[Mh] Termos MeSH secundário: Ácidos Graxos/análise
Cromatografia Gasosa-Espectrometria de Massas
Concentração de Íons de Hidrogênio
Óleos/química
Estramenópilas/citologia
Temperatura Ambiente
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Fatty Acids); 0 (Oils); EC 3.4.- (Endopeptidases); EC 3.4.99.- (alkaline protease)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180126
[St] Status:MEDLINE
[do] DOI:10.5650/jos.ess17166


  3 / 266735 MEDLINE  
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[PMID]:29216817
[Au] Autor:Nivala O; Faccio G; Arvas M; Permi P; Buchert J; Kruus K; Mattinen ML
[Ad] Endereço:VTT Technical Research Centre of Finland, Ltd., P.O. Box 1000, FI-02044, Espoo, Finland. outi.nivala@helsinki.fi.
[Ti] Título:Characterization of sulfhydryl oxidase from Aspergillus tubingensis.
[So] Source:BMC Biochem;18(1):15, 2017 12 08.
[Is] ISSN:1471-2091
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Despite of the presence of sulfhydryl oxidases (SOXs) in the secretomes of industrially relevant organisms and their many potential applications, only few of these enzymes have been biochemically characterized. In addition, basic functions of most of the SOX enzymes reported so far are not fully understood. In particular, the physiological role of secreted fungal SOXs is unclear. RESULTS: The recently identified SOX from Aspergillus tubingensis (AtSOX) was produced, purified and characterized in the present work. AtSOX had a pH optimum of 6.5, and showed a good pH stability retaining more than 80% of the initial activity in a pH range 4-8.5 within 20 h. More than 70% of the initial activity was retained after incubation at 50 °C for 20 h. AtSOX contains a non-covalently bound flavin cofactor. The enzyme oxidised a sulfhydryl group of glutathione to form a disulfide bond, as verified by nuclear magnetic resonance spectroscopy. AtSOX preferred glutathione as a substrate over cysteine and dithiothreitol. The activity of the enzyme was totally inhibited by 10 mM zinc sulphate. Peptide- and protein-bound sulfhydryl groups in bikunin, gliotoxin, holomycin, insulin B chain, and ribonuclease A, were not oxidised by the enzyme. Based on the analysis of 33 fungal genomes, SOX enzyme encoding genes were found close to nonribosomal peptide synthetases (NRPS) but not with polyketide synthases (PKS). In the phylogenetic tree, constructed from 25 SOX and thioredoxin reductase sequences from IPR000103 InterPro family, AtSOX was evolutionary closely related to other Aspergillus SOXs. Oxidoreductases involved in the maturation of nonribosomal peptides of fungal and bacterial origin, namely GliT, HlmI and DepH, were also evolutionary closely related to AtSOX whereas fungal thioreductases were more distant. CONCLUSIONS: AtSOX (55 kDa) is a fungal secreted flavin-dependent enzyme with good stability to both pH and temperature. A Michaelis-Menten behaviour was observed with reduced glutathione as a substrate. Based on the location of SOX enzyme encoding genes close to NRPSs, SOXs could be involved in the secondary metabolism and act as an accessory enzyme in the production of nonribosomal peptides.
[Mh] Termos MeSH primário: Aspergillus/enzimologia
Oxirredutases/metabolismo
[Mh] Termos MeSH secundário: Dissulfetos
Estabilidade Enzimática
Glutationa/metabolismo
Concentração de Íons de Hidrogênio
Oxirredutases/química
Oxirredutases/genética
Oxirredutases/isolamento & purificação
Peptídeo Sintases
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Disulfides); EC 1.- (Oxidoreductases); EC 1.8.3.- (sulfhydryl oxidase); EC 6.3.2.- (Peptide Synthases); EC 6.3.2.- (non-ribosomal peptide synthase); GAN16C9B8O (Glutathione)
[Em] Mês de entrada:1712
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171209
[St] Status:MEDLINE
[do] DOI:10.1186/s12858-017-0090-4


  4 / 266735 MEDLINE  
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[PMID]:29184996
[Au] Autor:Liu J; Liang Y; Shen J; Bai Q
[Ad] Endereço:Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Modern Separation Science Key Laboratory of Shaanxi Province, College of Chemistry & Materials Science, Northwest University, Xi'an, Shaanxi, 710069, China. jwliu@nwu.edu.cn.
[Ti] Título:Polymeric ionic liquid-assembled graphene-immobilized silica composite for selective isolation of human serum albumin from human whole blood.
[So] Source:Anal Bioanal Chem;410(2):573-584, 2018 Jan.
[Is] ISSN:1618-2650
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Polymeric ionic liquids (PILs) with 1-vinyl-3-ethylimidazolium cations and two different anions of Br and PF were assembled onto the surface of graphene (G) nanosheets. The derived two composites, i.e., PIL(Br)-G and PIL(PF )-G, were further efficiently immobilized onto the surface of silica nanoparticles via self-assembly technique. The obtained two PIL-G/SiO nanocomposites exhibited diverse adsorption performances toward proteins through adjusting the anions of PILs. Electrostatic attractions between proteins and the nanocomposites dominated protein adsorption, while the presence of PF anions weakened electrostatic interactions and deteriorated the selective adsorption of target protein, i.e., bovine serum albumin (BSA) in this case. Specifically, PIL(Br)-G/SiO nanocomposite displayed high selectivity toward BSA and a high adsorption efficiency of ca. 98% was achieved for 100 mg L BSA in a Britton-Robinson (B-R) buffer at pH 5. HPLC analysis demonstrated the selectivity of PIL(Br)-G/SiO nanocomposite toward BSA in the presence of abundant hemoglobin and cytochrome c. The practical applicability was verified by performing selective isolation of human serum albumin (HSA) from human whole blood. Graphical abstract Selective isolation of human serum albumin from blood by polymeric ionic liquid assembled graphene immobilized silica nanocomposite with tunable anions.
[Mh] Termos MeSH primário: Grafite/química
Líquidos Iônicos/química
Polímeros/química
Albumina Sérica Humana/isolamento & purificação
Dióxido de Silício/química
[Mh] Termos MeSH secundário: Adsorção
Ânions/química
Seres Humanos
Concentração de Íons de Hidrogênio
Nanocompostos/química
Eletricidade Estática
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anions); 0 (Ionic Liquids); 0 (Polymers); 7631-86-9 (Silicon Dioxide); 7782-42-5 (Graphite); ZIF514RVZR (Serum Albumin, Human)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171130
[St] Status:MEDLINE
[do] DOI:10.1007/s00216-017-0758-z


  5 / 266735 MEDLINE  
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[PMID]:28938141
[Au] Autor:Ye X; Li H; Zhang L; Chai R; Tu R; Gao H
[Ad] Endereço:Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, 130 Changjiang West Road, Hefei 230036, China.
[Ti] Título:Amendment damages the function of continuous flooding in decreasing Cd and Pb uptake by rice in acid paddy soil.
[So] Source:Ecotoxicol Environ Saf;147:708-714, 2018 Jan.
[Is] ISSN:1090-2414
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Combinations of remediation technologies are needed to solve the problem of soil contamination in paddy rice, due to multiple potential toxic elements (PTEs). Two potential mitigation methods, water management and in-situ remediation by soil amendment, have been widely used in treatment of PTE-polluted paddy soil. However, the interactive relationship between soil amendment and water management, and its influence on the accumulation of PTEs in rice are poorly understood. Greenhouse pot experiments were conducted to examine the effects of phosphate amendment on Cd and Pb availability in soil and their influence on Cd and Pb uptake into rice, on Fe and P availability in soil, and on the alteration of Fe amount and compartment on root surface among different water management strategies. Results indicated that Cd and Pb content in the shoot and grain were significantly affected by the different water management strategies in nonamended soils, and followed the order: wetting irrigation > conventional irrigation > continuous flooding. The application of phosphate amendment significantly decreased the variations of Cd and Pb absorption in shoot and grain of rice among different water treatments. The reasons may be attributed to the enhancement of P availability and the decrease of Fe availability in soil, and the decreased variations of Fe /Fe content in root coating after the application of phosphate amendment. These results suggested that the simultaneous use of phosphate amendment and continuous flooding to immobilize Cd and Pb, especially in acid paddy soils, should be avoided.
[Mh] Termos MeSH primário: Irrigação Agrícola/métodos
Cádmio/análise
Recuperação e Remediação Ambiental/métodos
Chumbo/análise
Oryza/química
Poluentes do Solo/análise
Solo/química
[Mh] Termos MeSH secundário: Ácidos
China
Grãos Comestíveis/química
Poluição Ambiental/prevenção & controle
Concentração de Íons de Hidrogênio
Modelos Teóricos
Oryza/crescimento & desenvolvimento
Raízes de Plantas/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Acids); 0 (Soil); 0 (Soil Pollutants); 00BH33GNGH (Cadmium); 2P299V784P (Lead)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170923
[St] Status:MEDLINE


  6 / 266735 MEDLINE  
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[PMID]:28938140
[Au] Autor:Yi X; He J; Guo Y; Han Z; Yang M; Jin J; Gu J; Ou M; Xu X
[Ad] Endereço:College of Chemistry, Fuzhou University, Fuzhou 350108, China. Electronic address: 927208329@qq.com.
[Ti] Título:Encapsulating Fe O into calcium alginate coated chitosan hydrochloride hydrogel beads for removal of Cu (II) and U (VI) from aqueous solutions.
[So] Source:Ecotoxicol Environ Saf;147:699-707, 2018 Jan.
[Is] ISSN:1090-2414
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:The aim of this work was to study the removal of Cu (II) and U (VI) ions from aqueous solutions by encapsulating magnetic Fe O nanoparticles into calcium alginate coated chitosan hydrochloride (CCM) hydrogel beads. ATR-FTIR and XRD analysis data indicated that the CCM composites were successfully prepared. SEM images and EDX spectra showed that Cu and UO ions were adhered onto sorbents. Adsorption properties for removal of both copper and uranium ions under various experimental conditions were investigated. Kinetic data and sorption equilibrium isotherms were also conducted in batch process. The sorption kinetic analysis revealed that sorption of Cu (II) and U (VI) followed the pseudo-second-order model well and exhibited 3-stage intraparticle diffusion model during the whole sorption process. Equilibrium data were best described by Langmuir model, and the CCM composite hydrogel beads showed the estimated maximum adsorption capacity 143.276mg/g and 392.692mg/g for Cu (II) and U (VI), respectively. The CCM adsorbent exhibited excellent reusability for five cycles use without significant changes in the adsorption capacity and structural stability. The results demonstrated that CCM can be an effective and promising sorbent for Cu (II) and U (VI) ions in wastewater.
[Mh] Termos MeSH primário: Alginatos/química
Quitosana/química
Cobre/análise
Nanopartículas de Magnetita/química
Compostos de Urânio/análise
Poluentes Químicos da Água/análise
Purificação da Água/métodos
[Mh] Termos MeSH secundário: Adsorção
Ácido Glucurônico/química
Ácidos Hexurônicos/química
Hidrogéis/química
Concentração de Íons de Hidrogênio
Íons
Cinética
Modelos Teóricos
Soluções
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Alginates); 0 (Hexuronic Acids); 0 (Hydrogels); 0 (Ions); 0 (Magnetite Nanoparticles); 0 (Solutions); 0 (Uranium Compounds); 0 (Water Pollutants, Chemical); 789U1901C5 (Copper); 8A5D83Q4RW (Glucuronic Acid); 8C3Z4148WZ (alginic acid); 9012-76-4 (Chitosan)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170923
[St] Status:MEDLINE


  7 / 266735 MEDLINE  
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[PMID]:28865349
[Au] Autor:Li X; Zhang D; Sheng F; Qing H
[Ad] Endereço:Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Conservancy, Chengdu 610041, China.
[Ti] Título:Adsorption characteristics of Copper (â…¡), Zinc (â…¡) and Mercury (â…¡) by four kinds of immobilized fungi residues.
[So] Source:Ecotoxicol Environ Saf;147:357-366, 2018 Jan.
[Is] ISSN:1090-2414
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:This study investigated the adsorption characteristics of Copper (â…¡), Zinc (â…¡) and Mercury (â…¡) by immobilized Flammulina velutipes, Auricularia polytricha, Pleurotus eryngii and Pleurotus ostreatus residues. Lagergren model, elovich and intraparticle diffusion model were used to present the adsorption kinetics, and it was proved that Langmuir isotherm model and pseudo-second order kinetics are the best suitable model with high correlation coefficient to characterize the adsorption process of Copper (â…¡), Zinc (â…¡) and Mercury (â…¡). The results showed that adsorption process finished in 120min at pH 6.0. The adsorption rate of Cu , Zn and Hg were reached to 53.8-84.1% of total in the initial 60min, and finished in 120min. Ion exchange and complexation of F. velutipes were the main mechanisms for adsorption of metal ions by characterizations of Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). In addition the functional group of cell walls such as hydroxyl, amide, carbonyl, phosphoric played a critical role in ions adsorption of edible mushroom residues. Cu , Zn and Hg in wastewater could be efficiently removed by F. velutipes residue with removal ratio of 73.11%, 66.67% and 69.35%, respectively.
[Mh] Termos MeSH primário: Agaricales/química
Cobre/análise
Mercúrio/análise
Modelos Teóricos
Poluentes Químicos da Água/análise
Zinco/análise
[Mh] Termos MeSH secundário: Adsorção
Cobre/química
Difusão
Concentração de Íons de Hidrogênio
Íons
Cinética
Mercúrio/química
Resíduos Sólidos/análise
Termodinâmica
Águas Residuais/química
Poluentes Químicos da Água/química
Purificação da Água/métodos
Zinco/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ions); 0 (Solid Waste); 0 (Waste Water); 0 (Water Pollutants, Chemical); 789U1901C5 (Copper); FXS1BY2PGL (Mercury); J41CSQ7QDS (Zinc)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170903
[St] Status:MEDLINE


  8 / 266735 MEDLINE  
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[PMID]:28841526
[Au] Autor:Rostamian R; Behnejad H
[Ad] Endereço:Department of Physical Chemistry, School of Chemistry, University College of Science, University of Tehran, Tehran 14155, Iran.
[Ti] Título:A comprehensive adsorption study and modeling of antibiotics as a pharmaceutical waste by graphene oxide nanosheets.
[So] Source:Ecotoxicol Environ Saf;147:117-123, 2018 Jan.
[Is] ISSN:1090-2414
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:The adsorption behavior of tetracycline (TCN), doxycycline (DCN) as the most common antibiotics in veterinary and ciprofloxacin (CPN) onto graphene oxide nanosheets (GOS) in aqueous solution was evaluated. The four factors influencing the adsorption of antibiotics (initial concentration, pH, temperature and contact time) were studied. The results showed that initial pH ∼ 6 to 7 and contact time ∼ 100 - 200min are optimum for each drug. The monolayer adsorption capacity was reduced with the increasing temperature from 25°C to 45°C. Non-linear regressions were carried out in order to define the best fit model for every system. To do this, eight error functions were applied to predict the optimum model. Among various models, Hill and Toth isotherm models represented the equilibrium adsorption data of antibiotics while the kinetic data were well fitted by pseudo second-order (PSO) kinetic model (DCN and TCN) and Elovich (CPN) models. The maximum adsorption capacity (q ) is found to be in the following order: CPN >> DCN > TCN, obtained from sips equation at the same temperature. The GOS shows highest adsorption capacity towards CPN up to 173.4mgg . The study showed that GOS can be removed more efficiently from water solution.
[Mh] Termos MeSH primário: Antibacterianos/análise
Grafite/química
Modelos Teóricos
Nanoestruturas/química
Poluentes Químicos da Água/análise
Purificação da Água/métodos
[Mh] Termos MeSH secundário: Adsorção
Antibacterianos/química
Ciprofloxacino/análise
Ciprofloxacino/química
Doxiciclina/análise
Doxiciclina/química
Concentração de Íons de Hidrogênio
Cinética
Óxidos/química
Temperatura Ambiente
Tetraciclina/análise
Tetraciclina/química
Termodinâmica
Drogas Veterinárias/análise
Drogas Veterinárias/química
Poluentes Químicos da Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (Oxides); 0 (Veterinary Drugs); 0 (Water Pollutants, Chemical); 5E8K9I0O4U (Ciprofloxacin); 7782-42-5 (Graphite); F8VB5M810T (Tetracycline); N12000U13O (Doxycycline)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170826
[St] Status:MEDLINE


  9 / 266735 MEDLINE  
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[PMID]:28471389
[Au] Autor:Liu Z; Wang CZ; Zhu XY; Wan JY; Zhang J; Li W; Ruan CC; Yuan CS
[Ad] Endereço:Institute of Agricultural Modernization, Jilin Agricultural University, Changchun 130118, China. lzhiiu@126.com.
[Ti] Título:Dynamic Changes in Neutral and Acidic Ginsenosides with Different Cultivation Ages and Harvest Seasons: Identification of Chemical Characteristics for Panax ginseng Quality Control.
[So] Source:Molecules;22(5), 2017 May 04.
[Is] ISSN:1420-3049
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:In this study, dynamic changes in ginsenoside content and ratios in the root were investigated with different cultivation ages and different collection months, using high-performance liquid chromatography (HPLC). Our data indicate that changes in ginsenoside Ro and malonyl ginsenosides content were dependent on the ginseng cultivation age ( < 0.05); especially, the Ro content varied from 0.16 to 4.91 mg/g, with a difference about 30-fold. Further, we found that the samples of 5 and 6-year-old had high Ro/Re ratio, whereas two and three-year-old possessed low Ro/Re ratio. Thus, the Ro/Re ratio can be used as a characteristic marker for differentiating the age of the root. The relative content of ginsenosides Rg1 and Re were affected by the ginseng's harvest season. The Re content was higher than the Rg1 content in May and June, but lower than the Rg1 content from August to October. Thus, the Rg1/Re ratio can be used as a characteristic marker for differentiating the ginseng's harvest seasons. These results indicate that the chemical characteristics of at different cultivation ages and harvest seasons are clearly different, which may cause differences in pharmacological activities and therapeutic effects. In addition, we developed HPLC coupled with hierarchical cluster analysis and principal component analysis methods to identify the cultivation age and harvest season of using characteristic ginsenosides. Our results showed that this method can be used to discriminate the cultivation age and harvest season of
[Mh] Termos MeSH primário: Ginsenosídeos/química
Panax/química
Estações do Ano
[Mh] Termos MeSH secundário: Cromatografia Líquida de Alta Pressão
Concentração de Íons de Hidrogênio
Controle de Qualidade
Reprodutibilidade dos Testes
[Pt] Tipo de publicação:JOURNAL ARTICLE; VALIDATION STUDIES
[Nm] Nome de substância:
0 (Ginsenosides)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE


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[PMID]:28466911
[Au] Autor:Scheller JS; Irvine GW; Wong DL; Hartwig A; Stillman MJ
[Ad] Endereço:Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada. martin.stillman@uwo.ca.
[Ti] Título:Stepwise copper(i) binding to metallothionein: a mixed cooperative and non-cooperative mechanism for all 20 copper ions.
[So] Source:Metallomics;9(5):447-462, 2017 May 24.
[Is] ISSN:1756-591X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Copper is a ubiquitous trace metal of vital importance in that it serves as a cofactor in many metalloenzymes. Excess copper becomes harmful if not sequestered appropriately in the cell. As a metal ion chaperone, metallothionein (MT) has been proposed as a key player in zinc and copper homeostasis within the cell. The underlying mechanisms by which MT sequesters and transfers copper ions, and subsequently achieves its proposed biological function remain unknown. Using a combination of electrospray ionization mass spectrometry (ESI-MS), circular dichroism (CD), and emission spectroscopy, we report that the Cu(i) to human apo-MT1a binding mechanism is highly pH-dependent. The 20 relative K -values for the binding of 1 to 20 Cu(i) to the 20 cysteines of MT were obtained from computational simulation of the experimental mass spectral results. These data identified the pH-dependent formation of three sequential but completely different Cu-S clusters, as a function of Cu(i) loading. These data provide the first overall sequence for Cu(i) binding in terms of domain specificity and transient binding site structures. Under cooperative binding at pH 7.4, a series of four clusters form: Cu S , followed by Cu S (ß), then a second Cu S (α), and finally Cu S (α) (x = up to 11). Upon further addition of Cu(i), a mixture of species is formed in a non-cooperative mechanism, saturating the 20 cysteines of MT1a. Using benzoquinone, a cysteine modifier, we were able to confirm that Cu S formed solely in the N-terminal ß-domain, as well as confirming the existence of the presumed Cu S cluster in the α-domain. Based on the results of ESI-MS and computational simulation we were able to identify Cu:MT speciation that resulted in specific emission and CD spectral properties.
[Mh] Termos MeSH primário: Cobre/metabolismo
Metalotioneína/metabolismo
[Mh] Termos MeSH secundário: Sítios de Ligação
Dicroísmo Circular
Cobre/química
Seres Humanos
Concentração de Íons de Hidrogênio
Metalotioneína/química
Modelos Moleculares
Ligação Proteica
Proteínas Recombinantes/química
Proteínas Recombinantes/metabolismo
Espectrometria de Massas por Ionização por Electrospray
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (MT1A protein, human); 0 (Recombinant Proteins); 789U1901C5 (Copper); 9038-94-2 (Metallothionein)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE
[do] DOI:10.1039/c7mt00041c



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