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1.
J Chromatogr A ; 1626: 461366, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797845

RESUMO

An alternative method for efficient synthesis of urea-functionalized silanes was proposed on the basis of an N, N'-carbonyldiimidazole-mediated acyl-transfer reaction between various amino-containing building blocks. The employment of different parent aminosilanes and alkylamines afforded an array of urea-containing silanes, which were subsequently immobilized onto silica gel to form corresponding urea-embedded alkyl stationary phases for high-performance liquid chromatography. The different substituents on the silicon core of the derivatized silane were found to significantly influence the final chromatographic behaviors. The comparative chromatographic characterization of thus-prepared silica packings with conventional octadecyl (C18) stationary phases revealed that the urea group was beneficial to suppress silanol activity towards basic probes, as well as to increase the water-compatibility of the alkyl stationary phases. The combination of a polar urea moiety and a non-polar long alkyl chain was favorable for an enhanced steric selectivity towards shape-constrained isomers. The polarizability-sensitive feature of such stationary phases made them good candidates for efficient separation of nitro-containing polar substances.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Silanos/química , Ureia/química , Isomerismo , Silanos/síntese química , Sílica Gel/química , Dióxido de Silício/química
2.
Nat Commun ; 11(1): 3535, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32669568

RESUMO

Macrophages are professional phagocytes known to play a vital role in controlling Mycobacterium tuberculosis (Mtb) infection and disease progression. Here we compare Mtb growth in mouse alveolar (AMs), peritoneal (PMs), and liver (Kupffer cells; KCs) macrophages and in bone marrow-derived monocytes (BDMs). KCs restrict Mtb growth more efficiently than all other macrophages and monocytes despite equivalent infections through enhanced autophagy. A metabolomics comparison of Mtb-infected macrophages indicates that ornithine and imidazole are two top-scoring metabolites in Mtb-infected KCs and that acetylcholine is the top-scoring in Mtb-infected AMs. Ornithine, imidazole and atropine (acetylcholine inhibitor) inhibit Mtb growth in AMs. Ornithine enhances AMPK mediated autophagy whereas imidazole directly kills Mtb by reducing cytochrome P450 activity. Intranasal delivery of ornithine or imidazole or the two together restricts Mtb growth. Our study demonstrates that the metabolic differences between Mtb-infected AMs and KCs lead to differences in the restriction of Mtb growth.


Assuntos
Autofagia/efeitos dos fármacos , Ornitina/farmacologia , Tuberculose/tratamento farmacológico , Ureia/química , Amônia/química , Animais , Apoptose , Arginase/química , Atropina/farmacologia , Proliferação de Células , Progressão da Doença , Feminino , Imidazóis/farmacologia , Macrófagos do Fígado/efeitos dos fármacos , Macrófagos do Fígado/microbiologia , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/microbiologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/química , Fosfatidilserinas/química , RNA Interferente Pequeno/metabolismo , Espécies Reativas de Oxigênio/química
3.
J Chromatogr A ; 1623: 461214, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505267

RESUMO

Plant hormones (PHs) are a type of pesticide that can potentially affect human health. Therefore, their quantitative detection is particularly important. In this study, a green and economic method for the simultaneous extraction and determination of four PHs, namely thidiazuron, forchlorfenuron, 1-naphthylacetic acid, and 2-naphthoxyacetic acid, in watermelon juice was developed by using m-aminophenol-urea-glyoxal resin as the adsorbent for pipette tip solid phase extraction (PT-SPE) coupled with liquid chromatography. The resin was synthesized via a simple (one pot hydrothermal synthesis) and green (ethanol as the solvent and glyoxal as crosslinking agent) process. The synthesized resin possesses multiple functional groups (hydroxyl, amino, and imino, among others), high adsorption capacity, larger specific surface area than the urea-glyoxal resin and m-aminophenol-glyoxal resin, and can be regenerated easily. The PT-SPE device is simple, cheap, and easy to obtain, and the adsorbent dosage is only 5.0 mg. The proposed method has a wide linear detection range, high recovery, good precision, and high sensitivity, and satisfies the measurement requirements for detecting trace levels of PHs in fruits and vegetables.


Assuntos
Aminofenóis/química , Citrullus/química , Sucos de Frutas e Vegetais/análise , Glioxal/química , Reguladores de Crescimento de Planta/análise , Resinas Vegetais/química , Extração em Fase Sólida/métodos , Ureia/química , Adsorção , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Ácidos Naftalenoacéticos/química , Praguicidas , Reprodutibilidade dos Testes
4.
J Chromatogr A ; 1623: 461197, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505286

RESUMO

Trifluoromethyl covalent organic framework (CF3-COF) is facilely synthesized at room temperature using for solid-phase microextraction (SPME). The CF3-COF coating displays an improved extraction performance for per- and polyfluorinated alkyl substances (PFASs) comparing to amorphous polymer coating, non-contained fluorine covalent organic framework coating and commercially available SPME coating. The fluorine affinity of trifluoromethyl in CF3-COF for PFASs is demonstrated using the density functional theory calculation. Following the microextraction with CF3-COF-coated fiber, the targeted PFASs are eluted with 1 mL acetonitrile and quantified by ultrahigh performance liquid chromatography tandem mass spectrometry. The low limits of detection are 0.1-0.7 pg g-1 for milk and 0.2-0.8 pg g-1 for milk powder, suggesting the outstanding sensitivity. The precision for the method ranges between 2.9 and 9.9%. The fiber-to-fiber repeatability is in the range of 4.2-9.5%. Under the optimum conditions, the relative recoveries are 91.0-110% with RSDs ≤ 10% for milk and 89.8-111% with RSDs ≤ 10% for milk powder.


Assuntos
Hidrocarbonetos Halogenados/isolamento & purificação , Estruturas Metalorgânicas/química , Leite/química , Microextração em Fase Sólida/métodos , Adsorção , Animais , Citrullus/química , Sucos de Frutas e Vegetais/análise , Glioxal/química , Concentração de Íons de Hidrogênio , Estruturas Metalorgânicas/síntese química , Fenóis/química , Reprodutibilidade dos Testes , Resinas Sintéticas/química , Ureia/química
5.
PLoS One ; 15(6): e0234544, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555670

RESUMO

Controlled-release and slow-release fertilizers can effectively supply nitrogen (N) while mitigating N loss. To determine the suitability of these fertilizers for plants in semi-arid environments, these fertilizers need to be evaluated under varying placement and temperature conditions. Several urea fertilizers were evaluated, including: uncoated, sulfur-coated (SCU), polymer-coated-sulfur-coated (PCSCU), and polymer-coated (PCU) with projected release timings between 45 and 180 d. Nitrogen release was measured under daily fluctuating or static temperatures applied either to the surface or buried in the soil. A second experiment consisted of two PCU sources and added a hanging bag placement comparison and low and high soil moisture treatments. For the first Experiment, the N in uncoated urea released shortly after application. The SCU and PCSCU treatments released > 80% of the N before the first sampling date. With fluctuating temperatures, the PCU 45, 75, 120, and 180 incorporated into the soil released N within +9, +9, -22, and -68 d of their expected timing. However, they released their N within 35 d when surface applied. Conversely, with static temperatures, PCU products released slowly, releasing under 80% for the entire study. The second experiment verified these results and showed no difference between low and high moisture and minimal release with fertilizer not in contact with soil. Each coated fertilizer in these studies exhibited slow/control release properties, but the PCU (surface applied) and SCU/PCSCU (surface applied or incorporated in soil) release was much more rapid than expected. Our research suggests that, although the SCU and PCSCU showed minimal slow-release properties (regardless of placement), the PCU fertilizers incorporated in the soil do have a controlled release approximate to what is expected, but have a much more rapid release when surface applied.


Assuntos
Agricultura , Preparações de Ação Retardada/farmacologia , Fertilizantes , Nitrogênio/farmacologia , Preparações de Ação Retardada/química , Nitrogênio/química , Polímeros/química , Solo/química , Enxofre/química , Temperatura , Ureia/química , Ureia/farmacologia
6.
Chem Biol Interact ; 326: 109137, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32442417

RESUMO

In the present study eighteen inhibitors of the hydrolytic enzymes of the endocannabinoid system were investigated for antioxidant activity using lipid peroxidation (LP) method. Among the assayed compounds ten belong to carbamates with phenyl [1,1'-biphenyl]-3-ylcarbamate (6), reported for the first time, and eight are retro-amide derivatives of palmitamine. Interestingly, results indicated that most of the tested compounds have good antioxidant properties. In particular, 1,3-di([1,1'-biphenyl]-3-yl)urea (3) shows IC50 = 26 ± 6 µM comparable to ones obtained for standard antioxidants trolox and quercetin (IC50 = 22 ± 6 µM and 23 ± 6 µM, respectively). Compound 3 was investigated further by means of DFT calculations, to clarify a possible mechanism of the antioxidant action. In order to estimate the capability of 3 to act as radical scavenger the structure was optimized at B3LYP/6-311++G** level and the respective bond dissociation enthalpies were calculated. The calculations in non-polar medium predicted as favorable mechanism a donation of a hydrogen atom to the free radical and formation of N-centered radical, while in polar solvents the mechanism of free radical scavenging by SPLET dominates over HAT H-abstraction. The possible radical scavenging mechanisms of another compound with potent antioxidant properties (IC50 = 53 ± 12 µM), the retro-amide derivative of palmitamine (compound 18), was estimated computationally based on the reaction enthalpies of a model compound (structural analogue to 18). The computations indicated that the most favorable mechanisms are hydrogen atom transfer from the hydroxyl group in meta-position of the benzamide fragment in nonpolar medium, and proton transfer from the hydroxyl group in ortho-position of the benzamide fragment in polar medium.


Assuntos
Compostos de Bifenilo/química , Peroxidação de Lipídeos/efeitos dos fármacos , Ureia/química , Anilidas/química , Antioxidantes/química , Benzamidas/química , Ácidos Graxos/química , Depuradores de Radicais Livres/química , Radicais Livres/química , Hidrogênio/química , Ácidos Palmíticos/química , Solventes/química
7.
Chemosphere ; 255: 126976, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32402890

RESUMO

Bentonite was modified by introducing humic acid (HA) into interlayer space of bentonite. The structural and physicochemical properties of modified bentonite were determined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray powder diffraction (XRD) and thermogravimetric analysis (TGA). The results showed that HA could enter the bentonite interlayer and increase the interlayer distance. Moreover, we were also investigated the high adsorption capacity and thermodynamics of modified bentonite to NH4+ cations in solutions. Under the same conditions, the NH4+ adsorption efficiency of modified bentonite (96.4%) was 69.2% higher compared with the natural bentonite (57.0%). The pseudo-second order kinetic model well fit the adsorption kinetics of NH4+ on modified bentonite, indicating that the adsorption type was chemical adsorption or chemisorptions. The isotherms fit well with Langmuir model, and the separation factor revealed that NH4+ on modified bentonite belonged to favorable adsorption. Compared with the natural bentonite, the modified bentonite exhibited a much lower leaching loss of NH4+-N and NO3--N in soil. Meanwhile, the loss of nitrogen caused by NH3 volatilization and N2O emission from soil could also be significantly attenuated by the combined application of modified bentonite and urea. The slower nitrogen release in the treatment combining modified bentonite and urea resulted in a greater yield and nitrogen uptake of wheat. Collectively, the modified bentonite could be used as nitrogen fertilizer synergist to enhance the nitrogen use efficiency.


Assuntos
Bentonita/química , Substâncias Húmicas , Nitrogênio/química , Adsorção , Fertilizantes , Concentração de Íons de Hidrogênio , Cinética , Solo/química , Espectroscopia de Infravermelho com Transformada de Fourier , Ureia/química
8.
Nature ; 581(7808): 339-343, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32433613

RESUMO

Cholesterol is an essential component of mammalian cell membranes, constituting up to 50% of plasma membrane lipids. By contrast, it accounts for only 5% of lipids in the endoplasmic reticulum (ER)1. The ER enzyme sterol O-acyltransferase 1 (also named acyl-coenzyme A:cholesterol acyltransferase, ACAT1) transfers a long-chain fatty acid to cholesterol to form cholesteryl esters that coalesce into cytosolic lipid droplets. Under conditions of cholesterol overload, ACAT1 maintains the low cholesterol concentration of the ER and thereby has an essential role in cholesterol homeostasis2,3. ACAT1 has also been implicated in Alzheimer's disease4, atherosclerosis5 and cancers6. Here we report a cryo-electron microscopy structure of human ACAT1 in complex with nevanimibe7, an inhibitor that is in clinical trials for the treatment of congenital adrenal hyperplasia. The ACAT1 holoenzyme is a tetramer that consists of two homodimers. Each monomer contains nine transmembrane helices (TMs), six of which (TM4-TM9) form a cavity that accommodates nevanimibe and an endogenous acyl-coenzyme A. This cavity also contains a histidine that has previously been identified as essential for catalytic activity8. Our structural data and biochemical analyses provide a physical model to explain the process of cholesterol esterification, as well as details of the interaction between nevanimibe and ACAT1, which may help to accelerate the development of ACAT1 inhibitors to treat related diseases.


Assuntos
Microscopia Crioeletrônica , Esterol O-Aciltransferase/química , Esterol O-Aciltransferase/ultraestrutura , Ureia/análogos & derivados , Colesterol/química , Colesterol/metabolismo , Histidina/química , Histidina/metabolismo , Holoenzimas/química , Holoenzimas/ultraestrutura , Humanos , Ligantes , Modelos Moleculares , Multimerização Proteica , Eletricidade Estática , Ureia/química
9.
J Chromatogr A ; 1623: 461169, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32376016

RESUMO

Artifacts due to metabolite extraction, derivatization, and detection techniques can result in aberrant observations that are not accurate representations of actual cell metabolism. Here, we show that α-ketoglutarate (α-KG) is reductively aminated to glutamate in methanol:water metabolite extracts, which introduces an artifact into metabolomics studies. We also identify pyridoxamine and urea as amine donors for α-KG to produce glutamate in methanol:water buffer in vitro, and we demonstrate that the addition of ninhydrin to the methanol:water buffer suppresses the reductive amination of α-KG to glutamate in vitro and in metabolite extracts. Finally, we calculate that glutamate levels have been overestimated by 10-50%, depending on cell line, due to α-KG reductive amination. These findings suggest that precautions to account for α-KG reductive amination should be taken for the accurate quantification of glutamate in metabolomics studies.


Assuntos
Artefatos , Ácido Glutâmico/análise , Ácidos Cetoglutáricos/química , Metabolômica , Aminação , Animais , Linhagem Celular , Ácido Glutâmico/química , Metanol/química , Ninidrina/química , Piridoxamina , Ureia/química
10.
Chemosphere ; 250: 126250, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32234618

RESUMO

Presence of even small amount of active pharmaceutical ingredients in the environment carries risks to human and animal health, presenting an important issue. The paper presents issues related to the new drug - pimavanserin (PMV). Biological treatment efficiency of pimavanserin (PMV) was evaluated using lab-scale Sequencing Batch Reactor (SBR). It has been shown to have a negative effect on aquatic organisms by classifying it as a toxic compound (EC50 = 8 mgL-1). The level of biological degradation of PMV was insufficient (37%) and intensively foam formation caused operational problems. For this reason, in this study polymers based on cyclodextrins (CDs) were synthesized and used as adsorbents alternative to active carbons to effectively separate PMV from real industrial waste streams. Crosslinked ß- and γ-CD polymers (ß- and γ-NS), obtained in reaction with 1,1'-carbonyldiimidazole (CDI), were fully characterized by physicochemical methods. The adsorption equilibrium data were interpreted using Freundlich and Langmuir models. The sorption process was fast (60 s) and the efficiency of PMV separation from model waste waters was 93% and 81% for ß- and γ-NS, respectively. Maximum polymer capacity was found at 52.08 mg g-1 for ß-NS and 23.26 mg g-1 for γ-NS. The interactions of PMV with CDs have been studied and indicate that major mechanism of the sorption is based on supramolecular interaction and capture to polymer network. Described biodegradable and reusable materials are perfect example of correctly selected adsorbent for separation of target substance from postproduction aqueous media.


Assuntos
Piperidinas/química , Ureia/análogos & derivados , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Celulose/química , Ciclodextrinas/química , Resíduos Industriais , Preparações Farmacêuticas , Polímeros/química , Ureia/química , Águas Residuárias , beta-Ciclodextrinas/química
11.
Food Chem ; 319: 126545, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32169764

RESUMO

A sol-gel urea colorimetric method was developed for the determination of urea in feedstuffs. The sol-gel platform contained p-dimethylaminobenzaldehyde (p-DMAB) as the reagent entrapped within polymer network. The urea analysis relied on the formation of Schiff base under acidic conditions. The colorimetric product was imaged with a Smartphone. Under optimized conditions, the calibration curve for urea was linear over the concentration range of 2.5-100 and 100-1000 mg L-1 with a good coefficient of determination (r2 > 0.99). The limit of detection (LOD) and limit of quantification (LOQ) were 0.1 and 0.5 mg L-1, respectively. The intra-day and inter-day precisions were 0.83-3.01%RSD and 2.20-5.47%RSD, respectively. Accuracy of urea analysis ranged from -1.15 to 2.76%. The proposed method was stable for at least 90 days. The amount of urea in feedstuff sample was determined. The developed method is easy to use with small samples and reagent consumption in field conditions for monitoring the quality of feedstuff.


Assuntos
Ureia/análise , Benzaldeídos/química , Colorimetria/métodos , Limite de Detecção , Transição de Fase , Ureia/química
12.
PLoS One ; 15(3): e0229907, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32182254

RESUMO

To investigate the effects of urea-formaldehyde (UF) resin impregnation combined heat treatment (IMPG-HT) on the pyrolysis behavior of poplar wood, the chemical composition, pyrolysis characteristics, pyrolysis kinetics, and gaseous products released during pyrolysis of untreated (control), IMPG-HT, IMPG and HT woods were analyzed. The results demonstrate that IMPG-HT changes pyrolysis behavior of poplar wood significantly. Unlike the control and HT samples, the thermogravimetric / derivative thermogravimetric (TG/DTG) curves of IMPG wood shift toward lower temperature, and the shoulder on DTG curves weaken or even disappear. The maximum mass loss rate of IMPG-HT samples decreases, and carbon residual yield increases to 23% or more and activation energy (E) increases sharply after conversion rate (α) reaching 0.80. HT improves the thermal stability of IMPG wood, which is represented by the increase of decomposition temperature (Td) and DTG peak temperature (Tpeak) and the higher E value of IMPG-HT wood. For the pyrolysis gaseous products, IMPG-HT wood produces nitrogen-containing gases (HNCO and NH3) due to the presence of UF resin, but the amounts of these gases are less than that produced by IMPG wood because the heat treatment had removed part of N elements.


Assuntos
Biomassa , Formaldeído/química , Pirólise/efeitos dos fármacos , Ureia/química , Madeira/química , Temperatura Alta , Cinética , Populus/química , Temperatura , Madeira/efeitos dos fármacos
13.
PLoS One ; 15(3): e0230057, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32142548

RESUMO

The rapid and reliable diagnostics of highly pathogenic bacteria under restricted field conditions poses one of the major challenges to medical biodefense, especially since false positive or false negative reports might have far-reaching consequences. Fluorescence in situ hybridization (FISH) has the potential to represent a powerful microscopy-based addition to the existing molecular-based diagnostic toolbox. In this study, we developed a set of FISH-probes for the fast, matrix independent and simultaneous detection of thirteen highly pathogenic bacteria in different environmental and clinical sample matrices. Furthermore, we substituted formamide, a routinely used chemical that is toxic and volatile, by non-toxic urea. This will facilitate the application of FISH under resource limited field laboratory conditions. We demonstrate that hybridizations performed with urea show the same specificity and comparable signal intensities for the FISH-probes used in this study. To further simplify the use of FISH in the field, we lyophilized the reagents needed for FISH. The signal intensities obtained with these lyophilized reagents are comparable to freshly prepared reagents even after storage for a month at room temperature. Finally, we show that by the use of non-toxic lyophilized field (NOTIFy)-FISH, specific detection of microorganisms with simple and easily transportable equipment is possible in the field.


Assuntos
Bactérias/genética , Armas Biológicas/classificação , Hibridização in Situ Fluorescente/métodos , Algoritmos , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Formamidas/química , Liofilização , Pele/microbiologia , Pele/patologia , Suínos , Temperatura , Ureia/química
14.
Nat Commun ; 11(1): 265, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31937783

RESUMO

Glucose electrolysis offers a prospect of value-added glucaric acid synthesis and energy-saving hydrogen production from the biomass-based platform molecules. Here we report that nanostructured NiFe oxide (NiFeOx) and nitride (NiFeNx) catalysts, synthesized from NiFe layered double hydroxide nanosheet arrays on three-dimensional Ni foams, demonstrate a high activity and selectivity towards anodic glucose oxidation. The electrolytic cell assembled with these two catalysts can deliver 100 mA cm-2 at 1.39 V. A faradaic efficiency of 87% and glucaric acid yield of 83% are obtained from the glucose electrolysis, which takes place via a guluronic acid pathway evidenced by in-situ infrared spectroscopy. A rigorous process model combined with a techno-economic analysis shows that the electrochemical reduction of glucose produces glucaric acid at a 54% lower cost than the current chemical approach. This work suggests that glucose electrolysis is an energy-saving and cost-effective approach for H2 production and biomass valorization.


Assuntos
Ácido Glucárico/análise , Glucose/química , Hidrogênio/análise , Biomassa , Catálise , Cloretos/química , Conservação de Recursos Energéticos , Eletrodos , Eletrólise , Compostos Férricos/química , Ácido Glucárico/química , Hidrogênio/química , Hidróxidos/química , Nanoestruturas/química , Níquel/química , Oxirredução , Ureia/química
15.
J Chromatogr A ; 1616: 460795, 2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31918849

RESUMO

Based on our previous work with "pseudostationary-ion exchanger sweeping", we use this strategy to develop a sensitive, reliable and robust method for the analysis of the newly-FDA approved hepatitis C antiviral drugs namely; sofosbuvir (SOV), daclatasvir (DAC), ledipasvir (LED) and velpatasvir (VEP) in their pure forms and co-formulated pharmaceutical dosage forms using micellar electrokinetic chromatography (MEKC) as a separation method. For the first time, a successful separation of all the investigated compounds was achieved in less than 8 min using a basic background electrolyte (BGE) composed of 25 mmol L-1 SDS + 20% (v/v) ACN (acetonitrile) in 10 mmol L-1 disodium tetraborate buffer (final apparent pH is 9.90). A special focus was given to optimize the composition of the sample matrix to maintain the solubility of the analytes within the sample zone while gaining additional benefits regarding analyte zone focusing. It was found that replacing phosphoric acid (as a sample matrix) with a zwitterionic/isoelectric buffering compound (L-glutamic acid) has a substantial positive impact on the obtained enrichment efficiency. The interplay of other enrichment principles such as the retention factor gradient effect (RFGE) is also discussed. A full validation study is performed based on the pharmacopeial and ICH guidelines. The obtained limits of detection and quantitation are as low as 0.63 and 1.3 µg mL-1; respectively for SOV and DAC and 1.3 and 2.5 µg mL-1; respectively for LED and VEP using UV-DAD as a detection method. The selectivity of the developed method for determination of the studied compounds in their pharmaceutical dosage forms or in the presence of ribavirin (RIB) or elbasvir (ELB), which are other prescribed medications in the treatment regimen of patients with hepatitis C virus infection, is demonstrated. It is shown that with acidic sample matrix and basic BGE, an efficient and precise approach was designed in which analyte adsorption on the capillary wall was minimized while keeping repeatable peak height, peak area and migration time together with the highest possible enrichment efficiency.


Assuntos
Antivirais/análise , Cromatografia Capilar Eletrocinética Micelar/métodos , Hepacivirus/efeitos dos fármacos , Sofosbuvir/análise , Adsorção , Antivirais/química , Benzimidazóis , Benzofuranos , Carbamatos/análise , Carbamatos/química , Ciclodextrinas/química , Formas de Dosagem , Eletrólitos/química , Fluorenos , Compostos Heterocíclicos de 4 ou mais Anéis/análise , Compostos Heterocíclicos de 4 ou mais Anéis/química , Humanos , Imidazóis/análise , Imidazóis/química , Limite de Detecção , Modelos Lineares , Metanol/química , Reprodutibilidade dos Testes , Sofosbuvir/química , Solubilidade , Temperatura , Ureia/química
16.
Chemosphere ; 242: 125247, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896173

RESUMO

Wood vinegar (WV) was applied alone or combined with biochar (BC) to observe their efficiency on suppressing the ammonia (NH3) volatilization from rice paddy soil. Five treatments, i.e., control (240 kg N ha-1 applied in urea), WV-5 and WV-10 (240 kg N ha-1 plus 5 and 10 t WV ha-1, respectively), and their counterparts WV-5-BC and WV-10-BC (WV-5 and WV-10 plus 7 t BC ha-1), were evaluated by a soil columns experiment. The N fertilizer was split applied as basal and two supplementary fertilizations (named BF, SF1 and SF2, respectively). The results showed that WV-5 treatment increased rice grain yield up to 11.2% compared to the control. Compared with the control, four WV-amended treatments, exhibited lower pH values of the floodwater (7.94-8.18 vs 8.47 and 7.85-7.91 vs 7.98) and the topsoil (6.52-6.76 vs 6.82 and 6.82-6.92 vs 6.99) during the BF and SF1 periods. Both WV-5 and WV-10 increased the NH4+-N contents of topsoil by 10.9-17.8% and 16.1-36.2% after BF and SF1, respectively, than control treatment. Additionally, the floodwater of the WV-amended treatments had higher NH4+-N concentration than control during the first three days after N fertilization, which can be attributed to the stimulating effect of WV on soil urease enzyme activity. WV did not effectively reduce NH3 volatilization as hypothesized. Interestingly, four WV-amended had relatively reduced the yield-scale NH3 volatilization by 13.6% than the control. It is suggested that WV needs to be applied with BC at a moderate rate to achieve optimum rice yield and mitigate NH3 volatilization.


Assuntos
Ácido Acético , Amônia/análise , Carvão Vegetal/química , Metanol , Amônia/química , Grão Comestível/química , Fertilizantes/análise , Nitrogênio/análise , Oryza/química , Solo/química , Ureia/química , Volatilização
17.
Eur J Med Chem ; 186: 111896, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31784185

RESUMO

We report here a thorough structure-activity relationship (SAR) with piperazinylureido sulfamates as inhibitors of human (h) carbonic anhydrase (CA, EC 4.2.1.1). A SAR investigation over the structure of reported anti-cancer zinc-binder CAIs such as SLC-0111 and S4 was carried out by including the urea outer nitrogen atom into a substituted piperazine ring reducing the linker flexibility. The derivatives were assessed for the inhibition of CA I, II and IV (off-target isoforms) and the tumor-associated CA IX (anticancer drug target). CA I and IV were not effectively inhibited, whereas many low nanomolar inhibitors were evidenced against CA II (KIs in the range of 1.0-705.5 nM), and IX (KIs in the range of 0.91-155.9 nM). Interestingly, a subset of CA II/IX selective inhibitors was detected which might represent interesting lead for the development of new anticancer strategies.


Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Piperazinas/farmacologia , Sulfonamidas/farmacologia , Ácidos Sulfônicos/farmacologia , Ureia/farmacologia , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/química , Relação Dose-Resposta a Droga , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Piperazinas/química , Relação Estrutura-Atividade , Sulfonamidas/química , Ácidos Sulfônicos/química , Ureia/análogos & derivados , Ureia/química
18.
Arch Microbiol ; 202(3): 645-656, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31776586

RESUMO

This study aimed to evaluate the effects of seed inoculation with Bradyrhizobium sp. and co-inoculation with Azospirillum brasilense. The seed treatments were as follows: control (without inoculation); A. brasilense (2 mL per kg-1 of seed); A. brasilense (4 mL per kg-1 of seed); Bradyrhizobium sp. (2 mL per kg-1 of seed); Bradyrhizobium sp. (4 mL per kg-1 of seed); A. brasilense + Bradyrhizobium sp. (2 mL of each strain per kg-1 of seed); and A. brasilense + Bradyrhizobium sp. (4 mL of each strain per kg-1 of seed). Peanut plants from seeds inoculated with Bradyrhizobium sp. and A. brasilense exhibited highest leaf concentration of photosynthetic pigments, carotenoids, nitrate, ammonia and amino acids. The inoculation of seeds with Bradyrhizobium sp. resulted in plants with increased concentrations of total soluble sugars, and ureides compared to the untreated plants. In contrast, seeds treated with A. brasilense alone resulted in plants exhibiting highest concentration of amino acids, which represent the highest concentration of nitrogen compounds in peanut plants. Seed inoculation with Bradyrhizobium sp. at a rate of 2 mL kg-1 was identified as the best treatment to promote increased biological nitrogen fixation and generate higher peanut yields.


Assuntos
Arachis/microbiologia , Bradyrhizobium/fisiologia , Sementes/crescimento & desenvolvimento , Ureia/metabolismo , Inoculantes Agrícolas/fisiologia , Arachis/crescimento & desenvolvimento , Arachis/metabolismo , Azospirillum brasilense/fisiologia , Fixação de Nitrogênio , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Sementes/metabolismo , Sementes/microbiologia , Ureia/química
19.
Chemistry ; 26(4): 888-899, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31696989

RESUMO

The anion-binding and transport properties of an extensive library of thiophene-based molecules are reported. Seventeen bis-urea positional isomers, with different binding conformations and lipophilicities, have been synthesized by appending α- or ß-thiophene or α-, ß-, or γ-benzo[b]thiophene moieties to an ortho-phenylenediamine central core, yielding six subsets of positional isomers. Through 1 H NMR, X-ray crystallography, molecular modelling, and anion efflux studies, it is demonstrated that the most active transporters adopt a pre-organized binding conformation capable of promoting the recognition of chloride, using urea and C-H binding groups in a cooperative fashion. Additional large unilamellar vesicle-based assays, carried out under electroneutral and electrogenic conditions, together with N-methyl-d-glucamine chloride assays, have indicated that anion efflux occurs mainly through an H+ /Cl- symport mechanism. On the other hand, the most efficient anion transporter displays cytotoxicity against tumor cell lines, while having no effects on a cystic fibrosis cell line.


Assuntos
Ânions/química , Cloretos/química , Tiofenos/química , Ureia/química , Transporte Biológico , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Transporte de Íons , Espectroscopia de Ressonância Magnética
20.
Chemistry ; 26(19): 4289-4296, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31834653

RESUMO

Cystobactamids belong to the group of arene-based oligoamides that effectively inhibit bacterial type IIa topoisomerases. Cystobactamid 861-2 is the most active member of these antibiotics. Most amide bonds present in the cystobactamids link benzoic acids with anilines and it was found that some of these amide bonds undergo chemical and enzymatic hydrolysis, especially the one linking ring C with ring D. This work reports on the chemical synthesis and biological evaluation of thirteen new cystobactamids that still contain the methoxyaspartate hinge. However, we exchanged selected amide bonds either by the urea or the triazole groups and modified ring A in the latter case. While hydrolytic stability could be improved with these structural substitutes, the high antibacterial potency of cystobactamid 861-2 could only be preserved in selected cases. This includes derivatives, in which the urea group is positioned between rings A and B and where the triazole is found between rings C and D.


Assuntos
Amidas/química , Compostos de Anilina/química , Antibacterianos/química , Bactérias/efeitos dos fármacos , Benzoatos/química , Triazóis/síntese química , Ureia/síntese química , Hidrólise , Estrutura Molecular , Triazóis/química , Ureia/química
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