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1.
Zhongguo Zhong Yao Za Zhi ; 44(15): 3246-3252, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31602879

RESUMO

Inula japonica was used as the research object, "3414" fertilization experiment were conducted to study the effects of nitrogen,phosphorus and potassium formula fertilizer on the growth and chemical composition content of I. japonica. The characteristics of fertilizer requirement were preliminarily revealed and the study provided fertilization guidance for artificial cultivation of I. japonica. The results showed that different nitrogen,phosphorus and potassium formula fertilizers had significant effects on plant morphology,physiological and biochemical indexes,dry matter accumulation and chemical composition content. The growth indexes and chemical components of I. japonica showed an upward trend with the increase of fertilization amount,especially the nitrogen fertilizer was the most significant. The indicators were analyzed by membership function. After comprehensive evaluation,the optimal nitrogen,phosphorus and potassium formula fertilization level was N3 P2 K2,namely high level nitrogen fertilizer,medium level phosphorus fertilizer and potassium fertilizer. I. japonica is a high fertilizer demand plant,and the rational fertilization scheme is " applying nitrogen fertilizer again and applying phosphorus and potassium fertilizer properly".


Assuntos
Fertilizantes , Inula/crescimento & desenvolvimento , Nitrogênio/química , Fósforo/química , Potássio/química , Inula/química
2.
Food Chem ; 298: 125081, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260952

RESUMO

The impact of kansui on the dough rheology and quality characteristics of chickpea-wheat composite flour-based noodles was investigated. For noodle dough, both the relative crystallinity and degree of order obtained from X-ray diffraction and Fourier transform infrared spectroscopy increased with the low level of kansui addition (0.5-1.5%), followed by a decreased trend at higher levels of alkali concentration (2.0-3.0%). Such variation was in accordance with the trend observed for G' and G″. Based on the confocal laser scanning microscopic observation for cooked noodle samples, the low concentration of kansui addition (0.5-1.5%) protected the well-embedded starch granules being disassociate from the gluten network, whereas with the increased alkali addition (2.0-3.0%), the protein network was impaired with a greater amount of ruptured starch granules being disassociated from the gluten network. The observation corresponded well with the electrophoretic profile, and the results of cooking properties, -SH content, and textural properties of cooked noodles.


Assuntos
Cicer/química , Farinha , Triticum/química , Carbonatos/química , Culinária , Qualidade dos Alimentos , Glutens/química , Microscopia Confocal , Potássio/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/química , Difração de Raios X
3.
Plant Physiol Biochem ; 141: 291-299, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31202193

RESUMO

Silicon (Si) is reported to improve salt stress tolerance of cereals, but little is known about the effects of Si on flows and partitioning of sodium (Na+), chloride (Cl-), and essential mineral ions at the tissue and cellular level. Wheat (Triticum aestivum L.) was exposed to 200 mM NaCl for 30 d in hydroponics, with or without 2 mM Si. X-ray microanalysis coupled with scanning electron microscopy (SEM) was used to quantify the cell-specific ion profiles across root and leaf cells, paralleled by measurements of wheat growth and physiological responses. Under salt stress, higher Na+ and Cl- concentrations were detected in root epidermal, cortical and stelar cells, eventually increasing their concentrations in different leaf cells, being highest in the epidermal cells and lowest in the vascular bundle cells. The potassium (K+) and magnesium (Mg2+) profiles were generally opposite to those of Na+ and Cl-. NaCl-dependent deregulation of essential nutrient homeostasis and excessive toxic ions accumulation in leaves was correlated with enhanced electrolyte leakage index (ELI), decreased chlorophyll contents, photosynthesis and other physiological parameters, and ultimately hampered plant growth. Conversely, Si addition improved the growth and physiological performance of salinized wheat by reducing Na+ and Cl- concentration in root epidermal and cortical cells, and it improved root uptake and storage of K+ and Mg2+ ions and their loading into xylem for distribution to shoots. These results suggest that Si-mediated inhibition of Na+ uptake, maintained nutrient homeostasis and improved physiological parameters to contribute to wheat growth improvement under salt stress.


Assuntos
Tolerância ao Sal , Sais/química , Silício/química , Triticum/crescimento & desenvolvimento , Biomassa , Cloretos/química , Clorofila/química , Produtos Agrícolas/crescimento & desenvolvimento , Microanálise por Sonda Eletrônica , Genótipo , Homeostase , Hidroponia , Íons , Microscopia Eletrônica de Varredura , Minerais , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Potássio/química , Salinidade , Plântula/crescimento & desenvolvimento , Sódio/química , Água/química
4.
Plant Physiol Biochem ; 141: 306-314, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207491

RESUMO

Prosopis strombulifera (Lam.) Benth. is a halophytic shrub found in highly saline soils in Argentina, with high tolerance against NaCl but strong growth inhibition by Na2SO4. In the present study, the differences in the physiological responses caused by these salts and an iso-osmotic combination thereof on photosynthesis, mineral composition and metabolism were analyzed. Na2SO4 treated plants were the most affected by salinity, showing a significant decrease in several photosynthetic parameters. Proline and cysteine accumulated significantly in the plants in response to salt stress. These results show by the first time that the SO42- anion is triggering damage in the photosynthetic apparatus and consequently affecting the photosynthetic process, which may explain the strong growth inhibition in these plants at high salinity. Moreover, the SO42- anion provoke challenges in the incorporation of nutrients, decreasing the levels of K, Ca, P and Mg, and inducing a strong antioxidant activity in P. strombulifera.


Assuntos
Fotossíntese , Prosopis/metabolismo , Cloreto de Sódio/química , Sulfatos/química , Ânions , Argentina , Cálcio/química , Clorofila/química , Grupo dos Citocromos b/metabolismo , Magnésio/química , Osmose/efeitos dos fármacos , Fósforo/química , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Potássio/química , Prosopis/efeitos dos fármacos , Ligação Proteica , Salinidade , Sódio/química
5.
Plant Physiol Biochem ; 141: 466-476, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31252252

RESUMO

The present study was aimed to investigate adaptation in physiology and biochemistry of Solanum lycopersicum seedlings under NaCl (NaCl0; 0.0 g NaCl kg-1 sand, NaCl1; 0.3 g NaCl/kg sand and NaCl2; 0.5 g NaCl/kg sand) stress, simultaneously supplemented with different (deprived; 0 mg/kg sand, LN; 105 mg/kg sand, MN; 210 mg/kg sand and HN; 270 mg/kg sand) levels of nitrogen (N). NaCl at both doses caused significant loss in growth, K+ content, K+/Na+ ratio, total chlorophyll and photosynthetic oxygen evolution. Further, N supplementation influences growth of test seedlings, that attained maximum growth in HN followed by MN, LN and deprived N conditions. N at HN level significantly declined Na+ accumulation in the cell and enhanced level of K+. NaCl treatment enhanced level of oxidative stress biomarkers: superoxide radical (O2•-), hydrogen peroxide (H2O2), MDA equivalents contents and electrolyte leakage in leaf as well as root despite enhanced activity of SOD, POD, CAT and GST, and enzymes participating in the ascorbate-glutathione cycle (AsA-GSH cycle) viz. APX, DHAR and GR. At the same time, higher contents of total AsA (AsA + DHA) and total GSH (GSH + GSSG), and maintained ratios of AsA/DHA and GSH/GSSG in HN fed seedlings were observed. Overall, the results suggest that HN supplementation was able in alleviating NaCl induced toxicity in test seedlings which was mainly due to the up-regulation of the AsA-GSH cycle, K+ and K+/Na+ ratio, which resulted into better growth performance of HN fed seedlings under NaCl stress while reverse was noticed for LN and deprive N conditions.


Assuntos
Lycopersicon esculentum/metabolismo , Nitrogênio/química , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Biomarcadores/metabolismo , Clorofila/metabolismo , Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Malondialdeído/metabolismo , Estresse Oxidativo , Oxigênio/metabolismo , Fotossíntese , Pigmentação , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Potássio/química , Plântula/metabolismo , Cloreto de Sódio/química
6.
Environ Pollut ; 251: 921-929, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31234258

RESUMO

The fast-growing production and application of carbon nanotube (CNT) materials in a variety of industrial products inevitably lead to their release to wastewater and surface water. CNT would experience oxidization in wastewater treatment plant due to the presence of large amount of disinfectants, such as H2O2 and O3, which in turn affects the environmental fates and risks of CNT. In this study, oxidized CNT materials (O-CNTs) were prepared by treating CNT with H2O2/UV and O3 (denoting as H2O2-CNT and O3-CNT, respectively). A variety of characterizations indicated that oxygen containing groups were generated on CNT surface upon the oxidation, and the O/C ratio increased in the order of pristine CNT < H2O2-CNT < O3-CNT. In the presence of Na+, K+ and Mg2+, the O-CNTs displayed better colloidal stability than the pristine CNT, and the stability increased with the oxidation degree (indicated by O/C ratio). This could be explained by the more negative surface charge and stronger hydrophilicity of the O-CNTs. Unexpectedly, in the presence of Ca2+, the most oxidized O3-CNT exhibited the poorest colloidal stability. The abundant carboxyl groups in O3-CNT provided effective binding sites for cation bridging effect through Ca2+ and led to stronger aggregation. Increasing pH was more favorable to disperse CNTs (both O-CNT and pristine CNT) in the presence of Na+, but much less effective in inhibiting the aggregation of O3-CNT in presence of Ca2+. This could be explained by the stronger cation bridging effect due to enhanced deprotonation the -COOH groups at higher pH conditions. The calculated Hamaker constants of the CNTs decreased with the oxidation degree, implying that there was lower van der Waals force between the O-CNTs. The Derjaguin-Landau-Verwey-Overbeek (DLVO) calculation confirmed that O-CNTs had to overcome higher energy barrier and thus showed better colloidal stability than the pristine CNT in the presence of Na+.


Assuntos
Coloides/química , Peróxido de Hidrogênio/química , Nanotubos de Carbono/química , Ozônio/química , Interações Hidrofóbicas e Hidrofílicas , Magnésio/química , Oxirredução , Potássio/química , Sódio/química , Águas Residuárias/química , Água/química
7.
Biochemistry (Mosc) ; 84(5): 562-569, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31234770

RESUMO

Amplification of GC-rich regions of genomic DNA is hindered either by high stability of DNA double helix or as a result of alternative structure formation by a guanine-rich DNA strand. Such potential G-quadruplex (G4) sequences are fairly common in promoters of the human genome. The efficiency of PCR amplification of promoter sequences for several human oncogenes (MYC, NRAS, TERT, KRAS, KIT) was studied. We demonstrate that the efficiency of DNA polymerase is reduced in the presence of potassium ions. The primer-extension technique localized DNA polymerase stops at the 3'-ends of potential quadruplex sequences. The structural and thermodynamic properties of short G-rich oligonucleotides corresponding to the stops of DNA polymerase were analyzed. These oligonucleotides formed stable parallel G4 in the presence of potassium ions. Correlation between the stability of G4 structure and efficiency of DNA polymerase stops was revealed. The results provide a method for detecting new G4 structures in extended genomic sequences and also clarify the mechanism of inhibition of DNA polymerase in G-rich regions of DNA.


Assuntos
DNA Polimerase Dirigida por DNA/metabolismo , Quadruplex G , Potássio/metabolismo , Dicroísmo Circular , DNA Polimerase Dirigida por DNA/química , Oligonucleotídeos/metabolismo , Reação em Cadeia da Polimerase , Potássio/química , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-myc/genética , Termodinâmica , Proteínas ras/genética
8.
Plant Physiol Biochem ; 141: 95-104, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31136935

RESUMO

Biostimulants improve yield, quality, and stress acclimation in crops. In this work, we tested the possibility of using phenolics-rich extracts from spelt (Triticum dicoccum L.) husks to attenuate the effects of salt stress (100-200 mM NaCl) in maize. Two methanolic extracts were prepared from the soluble-conjugated (SC), and the insoluble-bound (IB) phenolic acid fractions of the spelt husk, and their effects were investigated on several stress-associated biochemical parameters, such as proline, lipid peroxidation, H2O2, GSH levels, and ion content. Results show that SC and IB fractions of husk extracts behaved very differently, no doubt due to their greatly divergent chemical composition, as revealed by both GC-MS and HPLC analyses. The efficacy of treatments in mitigating salt stress was also dose- and timing-dependent. IB, even at the lower concentration tested, was able to recover the performance of stressed plants in terms of growth, photosynthetic pigments content, and levels of salt stress markers. Recovery of shoot growth to control levels and reduction of stress-induced proline accumulation occurred regardless of whether plants were pre-treated or post-treated with IB, whereas only pre-treatment with the higher dose of IB was effective in mitigating oxidative stress. Although in some cases SC and even methanol alone exerted some positive effects, they could also be deleterious whereas IB never was. Overall, results indicate that a polyphenol-containing extract obtained from spelt by-products can behave as biostimulant in maize plants and can mitigate their response to salt stress, by acting on different biochemical targets.


Assuntos
Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Estresse Salino , Triticum/química , Zea mays/química , Antioxidantes/química , Produtos Agrícolas/química , Cromatografia Gasosa-Espectrometria de Massas , Glutationa/química , Peróxido de Hidrogênio/química , Peroxidação de Lipídeos , Estresse Oxidativo , Fotossíntese , Compostos Fitoquímicos/química , Pigmentação , Folhas de Planta/química , Proteínas de Plantas/química , Potássio/química , Prolina/química , Tolerância ao Sal , Sódio/química
9.
Chemistry ; 25(39): 9287-9294, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31087418

RESUMO

The cyclic depsipeptide cereulide toxin it is a very well-known potassium electrogenic ionophore particularly sensitive to pancreatic beta cells. The mechanistic details of its specific activity are unknown. Here, we describe a series of synthetic substituted cereulide potassium ionophores that cause impressive selective activation of glucose-induced insulin secretion in a constitutive manner in rat insulinoma INS1E cells. Our study demonstrates that the different electroneutral K+ transport mechanism exhibited by the anionic mutant depsipeptides when compared with classical electrogenic cereulides can have an important impact of pharmacological value on glucose-stimulated insulin secretion.


Assuntos
Depsipeptídeos/farmacologia , Secreção de Insulina/efeitos dos fármacos , Ionóforos/química , Potássio/química , Animais , Transporte Biológico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Depsipeptídeos/síntese química , Depsipeptídeos/química , Glucose/farmacologia , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Microscopia Confocal , Potássio/metabolismo , Ratos
10.
Bioelectrochemistry ; 129: 90-99, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31132529

RESUMO

A dual magnetic-pH-sensitive hydrogel-based scaffold was studied for optimization of a cell microenvironment by scaffold mechanical deformation and its biochemical response. In particular, the positions of the seeding cells and the concentration of potassium (K+) within the scaffold were optimized by a multieffect-coupling magnetic-pH-stimuli (MECmpH) model based on (i) the threshold of the mechanical force required for a mechanotransduction effect at the cellular level, and (ii) the common biological requirement for cell growth. In this model, the physicochemical mechanisms of a magnetic hydrogel were characterized using magneto-chemo-electro-mechanical coupled effects, including hydrogel magnetization, diffusion of the solvent and ions, ionic polarization, and nonlinear deformation. After validation of the model with experimental data, it was found that a higher pH and current intensity at the electromagnet and a shorter hydrogel-magnet distance contribute to larger scaffold deformation and thus a stronger mechanical force on the cells. Moreover, the cell seeding positions within the magnetic scaffold were optimized for improved cell culture through controlled current intensity in the electromagnet. Furthermore, the physiological concentration of K+ was also optimized by the initial fixed charge density within the scaffold. We concluded that this optimized magnetic scaffold via the MECmpH model may provide an appropriate microenvironment for efficient cell growth.


Assuntos
Microambiente Celular , Hidrogéis/química , Imãs/química , Tecidos Suporte/química , Fenômenos Biomecânicos , Módulo de Elasticidade , Humanos , Concentração de Íons de Hidrogênio , Campos Magnéticos , Mecanotransdução Celular , Modelos Biológicos , Modelos Químicos , Potássio/química
11.
Luminescence ; 34(4): 402-406, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31033128

RESUMO

Photophysical phenomena associated with carbon nanoparticles in combination with biocompatibility and readily functionalizable properties have attracted significant interest for sensing and imaging applications. A potassium ion optode based on the fluorescence quenching of carbon quantum dots (CQDs) was constructed. The CQDs were synthesized using a microwave method, citric acid and 2,2'-(ethylene-dioxy)bis(ethylamine). A quantum yield of 7.1% was calculated for the synthesized CQDs. A linear dynamic range of about one-order of magnitude with a correlation coefficient of 0.99 was obtained. The optode was applied on real samples and a 0.60-1.60% error range was obtained relative to the ion-selective electrode.


Assuntos
Carbono/química , Fluorescência , Potássio/química , Pontos Quânticos/química , Eletrodos , Microscopia Eletrônica de Transmissão , Tamanho da Partícula
12.
Analyst ; 144(11): 3518-3524, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31020955

RESUMO

Mass spectrometry provides exquisite details on ligand and cation binding stoichiometries with a DNA target. The next important step is to develop reliable methods to determine the cation and ligand binding sites in each complex separated by using a mass spectrometer. To circumvent the caveat of ligand derivatization for cross-linking, which may alter the ligand binding mode, we explored a tandem mass spectrometry (MS/MS) method that does not require ligand derivatization, and is therefore also applicable to localize metal cations. By putting more negative charge states on the complexes using supercharging agents, and by creating radical ions by electron photodetachment, oligonucleotide bonds become weaker than the DNA-cation or DNA-ligand noncovalent bonds upon collision-induced dissociation of the radicals. This electron photodetachment (EPD) method allows one to locate the binding regions of cations and ligands by top-down sequencing of the oligonucleotide target. The very potent G-quadruplex ligands 360A and PhenDC3 were found to replace a potassium cation and bind close to the central loop of 4-repeat human telomeric sequences.


Assuntos
DNA/química , Quadruplex G , Potássio/química , Sequência de Bases , Sítios de Ligação , DNA/genética , DNA/metabolismo , Humanos , Ligantes , Potássio/metabolismo , Piridinas/química , Quinolinas/química , Análise de Sequência de DNA/métodos , Espectrometria de Massas em Tandem/métodos
13.
Molecules ; 24(8)2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-31018618

RESUMO

Trazodone, a well-known antidepressant drug widely used throughout the world, works as a 5-hydroxytryptamine (5-HT2) and α1-adrenergic receptor antagonist and a serotonin reuptake inhibitor. Our research aimed to develop a new method for the synthesis of trazodone and its derivatives. In the known methods of the synthesis of trazodone and its derivatives, organic and toxic solvents are used, and the synthesis time varies from several to several dozen hours. Our research shows that trazodone and its derivatives can be successfully obtained in the presence of potassium carbonate as a reaction medium in the microwave field in a few minutes. As a result of the research work, 17 derivatives of trazodone were obtained, including compounds that exhibit the characteristics of 5-HT1A receptor ligands. Molecular modeling studies were performed to understand the differences in the activity toward 5-HT1A and 5-HT2A receptors between ligand 10a (2-(6-(4-(3-chlorophenyl)piperazin-1-yl)hexyl)-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one) (5-HT1A Ki = 16 nM) and trazodone. The docking results indicate the lack of the binding of ligand 10a to 5-HT2AR, which is consistent with the in vitro studies. On the other hand, the docking results for the 5-HT1A receptor indicate two possible binding modes. Crystallographic studies support the hypothesis of an extended conformation.


Assuntos
Antagonistas Adrenérgicos/química , Antidepressivos/química , Técnicas de Química Sintética , Receptor 5-HT1A de Serotonina/química , Inibidores de Captação de Serotonina/química , Trazodona/análogos & derivados , Antagonistas Adrenérgicos/síntese química , Animais , Antidepressivos/síntese química , Sítios de Ligação , Carbonatos/química , Cristalografia por Raios X , Humanos , Ligantes , Micro-Ondas , Simulação de Acoplamento Molecular , Potássio/química , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Receptor 5-HT2A de Serotonina/química , Inibidores de Captação de Serotonina/síntese química , Homologia Estrutural de Proteína , Relação Estrutura-Atividade , Fatores de Tempo , Trazodona/síntese química
14.
J Environ Sci (China) ; 81: 136-147, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30975316

RESUMO

Potassium tungstophosphate is supported on BEA zeolite by in situ synthesis for glyphosate removal. Spectroscopic measurements identified hydrogen bonding as a primal interaction of potassium salt and BEA zeolite. Composites are evaluated for glyphosate herbicide removal and adsorption process is analyzed using two isotherm models. Obtained adsorption capacities for all prepared composites lay between 45.2 and 92.2 mg of glyphosate per gram of investigated composite. Suspension acidity revealed that glyphosate is adsorbed mainly in the zwitter-ion form at the composite surface while the amount of potassium salt in the composites is crucial for the adsorption application. Exceptional adsorption behavior is postulated to come from a high degree of homogeneity among surface active sites which is confirmed by different experimental methods. Temperature programmed desorption of glyphosate coupled with mass spectrometer detected one broad, high-temperature peak which represents overlapped desorption processes from active sights of similar strength. Introduction of potassium tungstophosphate affects active sites present in BEA zeolite for glyphosate desorption and significantly increases the amount of adsorbed pesticide in comparison to BEA zeolite. Supporting of potassium tungstophosphate on BEA zeolite via in situ synthesis procedure enables the formation of highly efficient adsorbents and revealed their perspective environmental application.


Assuntos
Modelos Químicos , Praguicidas/química , Potássio/química , Zeolitas/química , Adsorção , Glicina/análogos & derivados
15.
Molecules ; 24(7)2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-30959780

RESUMO

Hydrogenation of a lithium-potassium (double-cation) amide (LiK(NH2)2), which is generated as a product by ammonolysis of litium hydride and potassium hydride (LiH-KH) composite, is investigated in details. As a result, lithium amide (LiNH2) and KH are generated after hydrogenation at 160 °C as an intermediate. It is noteworthy that the mixture of LiH and KNH2 has a much lower melting point than that of the individual melting points of LiNH2 and KH, which is recognized as a eutectic phenomenon. The hydrogenation temperature of LiNH2 in the mixture is found to be significantly lower than that of LiNH2 itself. This improvement of reactivity must be due to kinetic modification, induced by the enhanced atomic mobility due to the eutectic interaction.


Assuntos
Amidas/química , Hidrogênio/química , Lítio/química , Potássio/química , Amônia/química , Hidrogenação , Cinética
16.
Environ Pollut ; 249: 398-405, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30913438

RESUMO

Interaction mechanisms of tetracycline (TC, as a typical antibiotic) on polystyrene microsphere (PSs, as a typical nanoplastic) were conducted by the batch, spectroscopic and theoretical techniques. The batch results showed that Na+ and K+ had no obvious effects on TC adsorption towards PSs, whereas Mg2+ significantly inhibited TC adsorption at pH > 5.0 due to its induced aggregations of PSs. The maximum TC adsorption capacity of PSs in the presence of humic acid (50.99 mg/g) was higher than that of PSs (44.77 mg/g) at pH 6.0. The highly effective adsorption was attributed to electrostatic attraction, π-π interaction and hydrophobic effect, which was determined by FT-IR and XPS analysis. According to DFT (density functional theory) calculations, the adsorption energy of TC/TC+ on PSs (1.52 eV) was significantly higher than that of negative TC- (0.57 eV), whereas minimum distance of TC on PSs (3.684 Å) was shorter than that of TC- on PSs (3.988 Å). The results of theoretical calculations indicated that TC was more preferably adsorbed on PSs with more stable configuration compared to TC-. These findings indicated that PSs can be used as a promising adsorbent for immobilization and pre-concentration of TC from aqueous solutions.


Assuntos
Antibacterianos/química , Nanosferas/química , Poliestirenos/química , Tetraciclina/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Concentração de Íons de Hidrogênio , Potássio/química , Sódio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
17.
Environ Sci Pollut Res Int ; 26(12): 12055-12070, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30827028

RESUMO

For elimination of cesium from aqueous solutions, mesoporous SBA-15 was synthesized and employed as the support for immobilization of potassium copper hexacyanoferrate. The synthesized adsorbent was characterized by various techniques and was used for adsorption of cesium. The results indicated that its adsorption capacity was 174.80 mg/g and superior to many studied adsorbents. The adsorbent represented good selectivity in the presence of some studied co-existing. The Temkin, Redlich-Peterson, Sips, Langmuir, and Freundlich isotherm models were used to evaluate the experimental data. The error analysis performed by EABS, ERRSQ, and HYBRID methods showed that the data was in good agreement with the Langmuir model indicating that the process was monoenergetic and the uptake of cesium forwarded through monolayer process. The pseudo-second-order model was recognized as the adequate model to describe the kinetic data of the adsorption process. The adsorption process was endothermic and spontaneous. The regeneration tests revealed that the adsorbent retained most of initial capacity after recovery.


Assuntos
Césio/análise , Modelos Químicos , Dióxido de Silício/química , Poluentes Químicos da Água/análise , Adsorção , Cobre/química , Ferrocianetos/química , Cinética , Potássio/química , Soluções , Termodinâmica , Água
18.
J Appl Microbiol ; 126(5): 1530-1540, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30758905

RESUMO

AIMS: The purpose of this study was to determine the positive effects of potassium-solubilizing bacteria and photosynthetic bacteria on the salt tolerance of maize. METHODS AND RESULTS: We selected the maize inbred lines USTB-265 (salt-sensitive), USTB-109 (moderately salt-tolerant) and USTB-297 (salt-tolerant) to investigate their growth characteristics, enzyme activity and gene expression in response to inoculation with photosynthetic bacteria and potassium-solubilizing bacteria under salt-stress conditions. CONCLUSIONS: Photosynthetic bacteria and potassium-solubilizing bacteria inoculation significantly enhanced the expression of antioxidant enzyme-related genes and increased the activities of the antioxidant enzymes superoxide dismutase, catalase and ascorbate peroxidase. In addition, inoculation with photosynthetic bacteria more efficiently improved maize salt tolerance than inoculation with potassium-solubilizing bacteria. While the effects of these bacteria differed among the three maize lines, both photosynthetic bacteria and potassium-solubilizing bacteria can enhance salt tolerance in maize. SIGNIFICANCE AND IMPACT OF THE STUDY: Soil salinization is one of the most critical factors affecting maize growth. These two types of bacteria (e.g. Bacillus mojavensis JK07 and Rhodopseudomonas palustris) have proven useful in salinized agricultural lands as bio-inoculants to increase crop productivity.


Assuntos
Bacillus , Potássio , Rodopseudomonas , Tolerância ao Sal/fisiologia , Zea mays , Bacillus/efeitos dos fármacos , Bacillus/metabolismo , Bacillus/fisiologia , Fotossíntese , Potássio/química , Potássio/metabolismo , Rodopseudomonas/efeitos dos fármacos , Rodopseudomonas/metabolismo , Rodopseudomonas/fisiologia , Zea mays/microbiologia , Zea mays/fisiologia
19.
ACS Comb Sci ; 21(2): 83-89, 2019 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-30602113

RESUMO

To develop a novel light-up probe and DNAzyme, we selected aptamers for N-methyl mesoporphyrin IX (NMM), a common fluorogenic analogue of coenzyme hemin, by a modified affinity chromatography-based systematic evolution of ligands by exponential enrichment (SELEX). Two truncated aptamers Nm1 and Nm2 with low micromolar dissociation constants (0.75 and 13.27 µM) were obtained after 11 rounds of selection and the final minimized 39-mer aptamer Nm2.1 showed 24-fold fluorescence enhancement for NMM at saturated concentration. Study of the interactions between aptamers and other porphyrin compounds by circular dichroism (CD) and absorption spectroscopy showed that Nm1 mainly assembled as a stem-loop structure, which exhibited a catalytic activity for the metal insertion reaction of mesoporphyrin IX with 3.3-fold rate enhancement. In contrast, the G-rich Nm2 and Nm2.1 were likely to form G-quadruplexes in the presence of alkali metal cations (K+ and Na+), which displayed excellent peroxidase activity exhibiting 19-fold higher catalytic efficiency than hemin alone. The selected aptamers could therefore be used as novel light-up fluorescent probes and DNAzymes by pairing with porphyrin compounds that have potential to construct sensors for various applications.


Assuntos
Hemina/química , Mesoporfirinas/química , Ácidos Nucleicos/química , Aptâmeros de Nucleotídeos/química , Catálise , Cátions Monovalentes , DNA Catalítico/química , Corantes Fluorescentes/química , Quadruplex G , Biblioteca Gênica , Cinética , Ligantes , Peroxidases/química , Potássio/química , Técnica de Seleção de Aptâmeros , Sódio/química , Termodinâmica
20.
Molecules ; 24(3)2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30682802

RESUMO

Desert soil is one of the most severe conditions which negatively affect the environment and crop growth production in arid land. The application of organic amendments with inorganic fertilizers is an economically viable and environmentally comprehensive method to develop sustainable agriculture. The aim of this study was to assess whether milk tea waste (TW) amendment combined with chemical fertilizer (F) application can be used to improve the biochemical properties of sandy soil and wheat growth. The treatments included control without amendment (T1), chemical fertilizers (T2), TW 2.5% + F (T3), TW 5% + F (T4) and TW 10% + F (T5). The results showed that the highest chlorophyll (a and b) and carotenoids, shoot and root dry biomass, and leaf area index (LAI) were significantly (p < 0.05) improved with all amendment treatments. However, the highest root total length, root surface area, root volume and diameter were recorded for T4 among all treatments. The greater uptake of N, P, and K contents for T4 increased for the shoot by 68.9, 58.3, and 57.1%, and for the root by 65.7, 34.3, and 47.4% compared to the control, respectively. Compared with the control, T5 treatment decreased the soil pH significantly (p < 0.05) and increased soil enzyme activities such as urease (95.2%), ß-glucosidase (81.6%) and dehydrogenase (97.2%), followed by T4, T3, and T2. Our findings suggested that the integrated use of milk tea waste and chemical fertilizers is a suitable amendment method for improving the growth and soil fertility status of sandy soils.


Assuntos
Fertilizantes/análise , Leite/química , Solo/química , Resíduos Sólidos , Chá/química , Triticum/crescimento & desenvolvimento , Agricultura , Animais , Biomassa , Carotenoides/metabolismo , Clorofila/metabolismo , Glucosidases/metabolismo , Nitrogênio/química , Nutrientes/química , Oxirredutases/metabolismo , Fósforo/química , Potássio/química , Urease/metabolismo
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