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1.
Chemosphere ; 240: 124953, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574435

RESUMO

Chemical characterization of PM2.5 and PM10 is important to identify potential compounds that induce biological responses that translate into cardio-respiratory health problems. This study shows the reliability of the use of crystalline phases, identified in samples from receptor sites, as source markers, helping researchers to infer the main sources of air pollution, even without the use of receptor models. PM2.5 and PM10 samples were collected at two sites in an urban industrialized region located at southeast of Brazil and analyzed by Synchrotron X-ray Diffraction to identify crystalline compounds. Results show 5 PM10 and PM2.5 species not previously reported in the literature. We propose reaction mechanisms for these species and identify specific sources for each crystalline phase found: BaTiO3 was found in PM10 receptor samples and proved to be a vehicular marker formed during brake action; maghemite (γ-Fe2O3), pyracmonite [(NH4)3Fe(SO4)3], ammonium perchlorate (NH3OHClO4) and potassium ferrate (K2Fe2O4) were found in PM2.5 proved to be markers of industrial activities. The crystalline phases found in PM samples from receptor sites and the mechanisms of reactions showed the reliability of the use of crystalline phases as source markers in the identification of potential sources of air pollution without misinterpretation of the likely source.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Material Particulado/química , Sulfato de Amônio/análise , Compostos de Bário/análise , Brasil , Compostos Férricos/análise , Indústrias , Compostos de Ferro/análise , Tamanho da Partícula , Percloratos/análise , Compostos de Potássio/análise , Compostos de Amônio Quaternário/análise , Reprodutibilidade dos Testes , Síncrotrons , Titânio/análise , Difração de Raios X/métodos
2.
Ecotoxicol Environ Saf ; 188: 109919, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31733935

RESUMO

In this paper, a process combining biodegradation and Fenton oxidation was proposed for the removal of polydiallyldimethylammonium chloride-acrylic-acrylamide-hydroxyethyl acrylate (PDM) in aqueous phase. Biodegradation of PDM was investigated in activated sludge systems, and the effects of the solution pH, mixed liquid suspended solids (MLSS), salinity, co-substrate, and initial substrate concentration, were studied. The biodegradation process was well-described with the Monod model and the values of the kinetics parameters vmax, ks were 0.05 h-1 and 333 mg/L. The optimal biodegradation conditions in the experimental range were determined to be: pH = 7.0, 0%-0.01% (w/v) NaCl, 4000 mg/L of MLSS, and 500 mg/L of glucose as co-substrate. FT-IR analysis indicated that PDM molecules biodegradation partly. The microbial community structures and dehydrogenase activity analysis revealed that PDM showed some toxicity to microorganisms in activated sludge. The effects of several parameters, including the pH and chemical doses, were investigated for removing PDM in Fenton oxidation process. The optimal Fenton oxidation process conditions in the experimental range were pH = 2.0, Fe2+ concentration of 40 mg/L, and H2O2 dosage of 23 mL/L. PDM was treated by biodegradation and subsequent Fenton oxidation under the optimal operating conditions. The removal efficiency was 44.5% after the biodegradation process and further increased to 85.5% after Fenton oxidation. The combined process was revealed to be a promising solution for achieving effective and economical removal of PDM.


Assuntos
Peróxido de Hidrogênio/química , Ferro/química , Polietilenos/análise , Compostos de Amônio Quaternário/análise , Esgotos , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Biodegradação Ambiental , Cinética , Oxirredução , Esgotos/química , Esgotos/microbiologia
3.
Anal Chim Acta ; 1079: 73-78, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31387721

RESUMO

In this study, we developed a novel bioelectronic taste sensor for the detection of specific bitter substances. A human bitter taste receptor, hT2R4, was efficiently expressed in Escherichia coli (E. coli), which was used as the primary recognition element. A simple and low-cost electrochemical device based on ITO-based electrolyte-semiconductor (ES) structure was innovatively employed as the transducer to assess bacterial metabolic consequences of receptor activation in real time. An apparent increase in extracellular acidification rate was observed, which was resulted from the triggering of hT2R4 receptors by their target ligand of denatonium. The sensor showed dose-dependent responses to denatonuim ranging from 50 nM to 500 nM, while non-bioengineered bacteria without hT2R4 receptors exhibited negligible responses to the same stimulus. In addition, the specificity of the proposed taste biosensor was verified using other typical bitter substances such as quinine and alpha-naphthylthiourea (ANTU). This research provides a simple and inexpensive approach for the construction of bioelectronic taste sensors.


Assuntos
Escherichia coli/genética , Compostos de Amônio Quaternário/análise , Quinina/análise , Receptores Acoplados a Proteínas-G/metabolismo , Tioureia/análogos & derivados , Sequência de Bases , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Humanos , Concentração de Íons de Hidrogênio , Compostos de Amônio Quaternário/metabolismo , Quinina/metabolismo , Receptores Acoplados a Proteínas-G/genética , Tioureia/análise , Tioureia/metabolismo
4.
Artigo em Inglês | MEDLINE | ID: mdl-31230515

RESUMO

This study investigated the feasibility of the methanogenic treatment of electronic industry wastewater containing tetramethylammonium hydroxide (TMAH), monoethanolamine (MEA) and sulfate in a lab-scale mesophilic up-flow anaerobic sludge blanket reactor. Feeding a mixture of electronic industry wastewater and co-substrate organics to the reactor for smooth acclimatization of sludge gave complete degradation of each organics within five days. When the reactor was fed only electronic industry wastewater, total COD removal, TMAH removal and MEA removal were achieved over 80, 99 and 99%, respectively, at an organic loading rate of 11.5 kg-COD m-3 day-1. 173 mg-S L-1 of influent sulfate was almost reduced simultaneously with the COD removal. In order to evaluate performance stability, the TMAH shock load event was performed under the conditions of 11,000 mg-COD L-1 for 24 h. Inflow of high TMAH concentration inhibited TMAH degradation and sulfate reduction for more than one month, however, not MEA. The batch feeding experiment and specific activity measurement revealed degradation pathways of each organics. TMAH was degraded via methanogenic pathway without sulfate reduction, MEA was degraded via methanogenic pathway with sulfate reduction. The results indicated that methanogenic treatment was applicable to electronic industry wastewater by appropriate reactor handling.


Assuntos
Reatores Biológicos/microbiologia , Etanolamina/análise , Compostos de Amônio Quaternário/análise , Sulfatos/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Euryarchaeota/metabolismo , Esgotos/química , Esgotos/microbiologia
5.
Food Chem ; 294: 355-367, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126475

RESUMO

The aim of the study was to initiate an exhaustive strategy of control by implementing both targeted and non-targeted metabolomics approaches. A LC-MS/MS method including an oxidative step for most of dyes was developed and validated to target the analysis of 14 residues belonging to different families of dyes. The method was suitable for the quantitative confirmation of 13 dyes at low ppb levels. The metabolomics approach objective was to compare fingerprints between farmed fish treated with malachite green and farmed fish treated with victoria pure blue bo. Analytical information on modifications in the metabolome of muscle, liver and plasma was exploited by HRMS following by multivariate statistics and revealed some direct or endogenous metabolites among relevant mass features contributing to the constructed models. These two approaches, either appropriate biomarkers either enlarged targeted dyes are explored concomitantly to help improving the strategy for tracking new illegal practices in aquaculture.


Assuntos
Corantes/análise , Metabolômica/métodos , Espectrometria de Massas em Tandem/métodos , Animais , Aquicultura , Cromatografia Líquida de Alta Pressão , Corantes/metabolismo , Peixes/metabolismo , Músculos/química , Músculos/metabolismo , Compostos de Amônio Quaternário/análise , Compostos de Amônio Quaternário/metabolismo , Corantes de Rosanilina/análise , Corantes de Rosanilina/metabolismo
6.
Biofouling ; 35(3): 284-298, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-31014110

RESUMO

The scientific multistep approach described herein is a result of two years of research into a control method against microbial fouling and biodeterioration of historic building materials by phototrophs. A series of tests were conducted to select the best antifouling agent for eliminating 'green' coatings and protecting surfaces against biofouling. Of the seven active compounds, two with the best penetration abilities were subjected to a photosynthetic activity inhibition test using confocal microscopy. Of the two, a quaternary ammonium salt (QAC) - didecyldimethylammonium chloride (DDAC) - was found to be the most effective. Ten biocides containing QACs at different concentrations were then tested against 'green' coatings on wood, brick and plaster, with the best four being selected for further research in model conditions. As a result, biocides containing >14% (v v-1) DDAC were found to be successful antifouling agents for protecting historical materials against biodeterioration by phototrophs.


Assuntos
Incrustação Biológica , Fósforo/farmacologia , Ar , Desinfetantes/análise , Compostos de Amônio Quaternário/análise , Madeira
7.
Water Sci Technol ; 79(1): 41-50, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30816861

RESUMO

Quaternary ammonium compounds (QACs) are surface-active organic compounds common in industrial cleaner formulations widely used in various sanitation applications. While acting as effective pathogenic biocides, QACs lack selective toxicity and often have poor target specificity. As a result, adverse effects on biological processes and thus the performance of biological nutrient removal (BNR) systems may be encountered when QACs enter wastewater treatment plants (WWTPs). Because of these impacts, there is motivation to screen wastewater influents for QACs and for process engineers to consider the inhibition effects of QACs on process evaluation and design of BNR plants. This paper introduces a mathematical model to describe the fate of QACs in a WWTP via biodegradation and bio-adsorption, and the inhibitory effect of QACs on nitrifiers and ordinary heterotrophic organisms. The model was incorporated as an add-on model in BioWin 5.3 and simulations of experimental systems were used for comparison of model results to measured data reported in the literature. The model was found to accurately predict the bulk phase concentration of QAC and the inhibition of nitrification with QAC concentrations ≥2 mg/L. This work provides a preliminary framework for simulation of BNR plants receiving inhibitory substances in the influent.


Assuntos
Modelos Químicos , Compostos de Amônio Quaternário/análise , Esgotos , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Nitrogênio/análise , Fósforo/análise , Eliminação de Resíduos Líquidos/estatística & dados numéricos , Águas Residuárias , Poluição da Água/estatística & dados numéricos
8.
Chemosphere ; 221: 132-140, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30639809

RESUMO

The increasing finding of pathogens and antibiotic resistance genes (ARGs) in drinking water has become one of the most challenging global health threats worldwide. However, conventional disinfection strategies in drinking water treatment plants (DWTPs) require further optimization in combating the antibiotic resistome. Here, we show that antimicrobial resins with quaternary ammonium salts (AMRs-QAS) exhibit great potentials in diminishing specific potential pathogens that relatively resist chlorine or UV disinfection in DWTPs, and comprehensive analyses using microscopy and fluorescence techniques revealed that the antimicrobial capacity of AMRs-QAS mainly proceed via the bacterial adsorption and cell membrane dissociation. Moreover, a total of 15 among 30 selected ARGs, as well as 4 selected potential pathogens including Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli and Staphylococcus aureus were all detected in the source water. Coupling the AMRs-QAS with 0.2 mg/L chlorine resulted in higher removal efficiencies than chlorination (2 mg/L) or UV disinfection (400 mJ cm-2) for all the detected pathogens and ARGs in drinking water and significantly decreased the relative abundances of Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, as well as all the detected ARGs (p < 0.05). Co-occurrences of pathogens and ARGs were revealed by a correlation network and possibly accounts for the ARGs removal. This coupled disinfection strategy overcomes the limitations of individual disinfection methods, i.e. the enrichment of specific pathogens and ARGs among bacterial populations, and provides an alternative for minimizing health risks induced by the antibiotic resistome in DWTPs.


Assuntos
Antibacterianos , Desinfecção , Água Potável/química , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Resinas Vegetais/farmacologia , Purificação da Água/métodos , Antibacterianos/análise , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Desinfecção/métodos , Água Potável/análise , Genes Bacterianos/efeitos dos fármacos , Halogenação , Compostos de Amônio Quaternário/análise , Raios Ultravioleta
9.
J Chromatogr A ; 1592: 101-111, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-30638711

RESUMO

In this study, a modified Quick Polar Pesticides (QuPPe) method, optimized by a central composite design, was developed to determine quaternary ammonium pesticides (QUATs) residues in barley and wheat by ultra-high-performance liquid chromatographic tandem mass spectrometry (UHPLC-MS/MS) using a hydrophilic interaction chromatography (HILIC) column. Considering the high polarity of these compounds, special conditions of sample preparation and analysis are required. Different mobile phases, extraction procedure and clean-up were evaluated. An isocratic elution with aqueous solution of ammonium formate 60 mmol L-1 (pH 3.7) and acetonitrile, 40:60 (v/v), was selected. Water and acidified methanol as extraction solvent, without heating, and a clean-up with dichloromethane, chitosan and acetonitrile presented good results. The validated method presented satisfactory selectivity, linearity, matrix effect, trueness and precision, providing recoveries from 93 to 110% with RSD < 13% for barley, and 70 to 115% with RSD < 18% for wheat. The complexity of these matrices requires the calibration in matrix and the diluted standard addition calibration (DSAC) procedure has been shown to be an excellent option to compensate for the matrix effect and the losses of the analytes in the extraction. Real samples of barley and wheat were analyzed and 60% presented concentrations of paraquat above the maximum limits allowed by the European Union. The modified QuPPe method combined with DSAC and HILIC-UHPLC-MS/MS demonstrated to be an effective approach to determine QUATs in barley and wheat, and is a good alternative for routine analysis. The use of the biosorbent chitosan is effective, low cost and more ecological when compared to others conventional sorbents.


Assuntos
Cromatografia Líquida , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Hordeum/química , Praguicidas/análise , Espectrometria de Massas em Tandem , Triticum/química , Calibragem , Clormequat/análise , Diquat/análise , Paraquat/análise , Piperidinas/análise , Compostos de Amônio Quaternário/análise
10.
Nat Prod Res ; 33(9): 1322-1328, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-29781300

RESUMO

Capparis spinosa L. is a perennial plant typical of the Mediterranean flora and a multipurpose plant used for curing various human ailments. Quaternary ammonium compounds (QACs), as constituents of Capparaceae, play important roles in protecting against abiotic stress. Aim of this work was to determine QACs in root and leaves of caper from two proveniences. The presence of stachydrine, choline, glycine betaine and homo-stachydrine has been confirmed by high resolution MS, while 1H NMR was applied to quantify the main QACs in the aqueous extracts. Stachydrine was quantified at 20.2 mg/g and 32.3 mg/g on dry leaves from South of Italy and Saudi Arabia, respectively, while a minor content was in dry roots (from 10.4 to 12.5 mg/g). Choline was considerably lower both in leaves and roots (from 0.3 to 1.2 mg/g). To our knowledge, this is the first report on the determination of QACs both in root and leaves of C. spinosa.


Assuntos
Capparis/química , Folhas de Planta/química , Raízes de Plantas/química , Compostos de Amônio Quaternário/análise , Colina/análise , Cromatografia Líquida de Alta Pressão , Humanos , Itália , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Extratos Vegetais/análise , Extratos Vegetais/química , Plantas Medicinais/química , Prolina/análogos & derivados , Prolina/análise , Compostos de Amônio Quaternário/química , Arábia Saudita
11.
Biologicals ; 57: 21-28, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30447860

RESUMO

The cationic polyelectrolyte pDADMAC is widely used in biopharmaceutical industry as a flocculating agent to enhance clarification throughput and downstream filtration operations. Due to the possible toxicity, pDADMAC should be assessed for an acceptable residual level to ascertain the safety of the product to patients. The strong protein-polyelectrolyte interaction, however, can negatively affect sensitivity and accuracy of measurements. This paper reports on the application of size exclusion (SE) chromatography coupled to evaporative light scattering detector (ELSD) to the quantitative determination of pDADMAC in monoclonal antibody formulations and in process intermediates during downstream purification. The SE chromatography was performed under isocratic condition with a mobile phase consisting of 0.1% TFA in water (90%) and acetonitrile (10%) at a flow rate of 0.4 ml/min. A quantification limit (S/N = 10) of 0.85 ppm was achieved in sample matrix, which is sufficiently low for the trace analysis of this compound in protein-containing samples.


Assuntos
Anticorpos Monoclonais/análise , Cromatografia em Gel/métodos , Difusão Dinâmica da Luz/métodos , Polietilenos/análise , Compostos de Amônio Quaternário/análise , Anticorpos Monoclonais/imunologia , Humanos , Estrutura Molecular , Polietilenos/química , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/imunologia , Reprodutibilidade dos Testes
12.
São Paulo; s.n; s.n; 2019. 79 p. graf, tab, ilus.
Tese em Português | LILACS | ID: biblio-1007570

RESUMO

Compostos de amônio quaternário (QACs) têm sido amplamente utilizados como desinfetantes e antissépticos, sendo essenciais na prevenção e controle de infecções bacterianas na medicina humana e veterinária. Embora patógenos prioritários multirresistentes têm sido muito bem caracterizados quanto ao perfil de suscetibilidade e contexto genético da resistência aos antibióticos, dados de resistência aos QACs são limitados. Assim, o objetivo do presente estudo foi avaliar a atividade in vitro dos QACs de uso doméstico e hospitalar [cloreto de benzalcônio (BAC), cloreto de cetilpiridinio (CPC) e brometo de cetiltrimetilamônio (CTAB)], contra patógenos prioritários multirresistentes, identificando os principais genes de resistência associados. Foram estudadas 100 cepas multirresistentes previamente sequenciados usando as plataformas Illumina MiSeq e NextSeq representativas de diferentes hospedeiros (humanos e animais) e fontes (ambientes e alimentos). As cepas foram identificadas como Klebsiella pneumoniae (n= 24), Escherichia coli (n= 30); Pseudomonas aeruginosa (n= 10), Enterobacter spp, (n= 8), Acinetobacter baumannii (n= 11) e Salmonella spp. (n= 17). Genes de resistência aos QACs foram identificados in silico através do alinhamento dos contigs obtidos de cada cepa sequenciada com genes de referência obtidos do GenBank, utilizando o programa Geneious versão 8 (Biomatters Ltd). A identidade de cada gene foi analisada utilizando o programa BLASTx, no qual um critério baseado em ≥90% identidade resultou na identificação dos genes mdfA (77%), qacE (44%), qacEΔ1 (43%), sugE(c) (29%), emrE (21%), qacA (19%), sugE(p) (5%), qacF (7%), qacH (7%) e qacL (7%) em 85 cepas; enquanto que 15 cepas não possuíam nenhum gene de resistência aos QACs. A concentração inibitória mínima (CIM) dos QACs para as 100 cepas foi determinada pelo método de microdiluição em caldo. Os resultados sugeriram que a resistência em patógenos prioritários circulando na interface humano-ambiente-animal não é restrita aos antibióticos, uma vez que a elevada ocorrência de genes qacE, qacEΔ1 e mdfA poderia estar associada com uma redução da suscetibilidade para QACs. Consequentemente, a resistência aos QACs poderia também contribuir para a persistência e adaptação destes patógenos nos seres humanos e outros animais, assim como em ambientes impactados antropogenicamente


Quaternary ammonium compounds (QACs) have been widely used as disinfectants and antiseptics, being applied as essential compounds in the prevention and control of bacterial infections in human-and veterinary hospital medicine. Although multiresistant priority pathogens have been well characterized with respect to their susceptibility profile and their genetic context of resistance for antibiotics, studies of resistance to QACs are limited. Thus, the objective of the present study was to evaluate the in vitro activity of QACs [(benzalkonium chloride (BAC), cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CTAB)] for household and hospital use against multiresistant priority pathogens, identifying the main resistance genes associated. A hundred multiresistant isolates (previously sequenced using the Illumina MiSeq and NextSeq platforms), representative of different hosts (humans and animals) and sources (environment and food) were studied. Isolates were identified as Klebsiella pneumoniae (n=24), Escherichia coli (n=30), Pseudomonas aeruginosa (n=10), Enterobacter spp. (n=8), Acinetobacter baumannii (n=11) and Salmonella spp. (n=17). In silico analysis for identification of genes conferring resistance to QACs were performed by aligning the contigs obtained from the strains with reference genes deposited in GenBank, using the Geneious version program (Biomatters Ltd). Similarities were analyzed using the BLASTx online program, considering the alignment criteria based on ≥ 90% identity. The result of these analysis revealed the presence of the following QAC genes: mdfA (77%), qacE (44%), qacEΔ1 (43%), sugE(c) (29%), emrE (21%), qacA (19%), sugE (p) (5%), qacF (7%), qacH (7%) e qacL (7%); while 15 strains showed no resistance genes for QACs. Determination of QACs minimum inhibitory concentration (MIC) for the 100 isolates, by the broth microdilution method. These results suggest that resistance to QACs in priority pathogens, circulating at the human-environment-animal interface, is not restricted to antibiotics, since the high occurrence of genes qacE, qacEΔ1 and mdfA were associated with a reduced susceptibility to QACs. Consequently, resistance to QACs could also contribute to the persistence and adaptation of these pathogens in humans and othes animals, as well as in anthropogenically impacted environments


Assuntos
Técnicas In Vitro/instrumentação , Compostos de Amônio Quaternário/análise , Noxas , Técnicas de Laboratório Clínico/instrumentação
13.
Mar Pollut Bull ; 136: 276-281, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30509808

RESUMO

In this work, the distribution of quaternary ammonium compounds (QACs) in two dated sediment cores, collected from the Pearl River Estuary (PRE) and Tokyo Bay (TB), were investigated to understand the historical input of QACs and their diagenetic behavior in urban estuarine environments. The vertical variation profiles of QAC concentrations showed that benzylalkyldimethyl ammonium compounds (BACs) and dialkyldimethyl ammonium compounds (DADMACs) were widely used during 1970s and 1980s both in China and Japan. The declining environmental concentrations of QACs suggested a compositional change of commodities and the effectiveness of emission control strategies. For the individual QAC homologues, BAC homologues decreased significantly over time, while DADMAC compositions remained relatively stable. The differences in concentration and composition profiles of BACs and DADMACs in the sediment cores provided useful information on the patterns of use of QACs in China and Japan, as well as their diagenetic behaviors in the sediments.


Assuntos
Sedimentos Geológicos/análise , Compostos de Amônio Quaternário/análise , Poluentes Químicos da Água/análise , Baías , China , Estuários , Japão , Rios , Tóquio
14.
Sensors (Basel) ; 18(10)2018 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-30332841

RESUMO

Voltammetric DNA sensor has been proposed on the platform of glassy carbon electrode covered with carbon black with adsorbed pillar[5]arene molecules. Electropolymerization of Neutral Red performed in the presence of native or oxidatively damaged DNA resulted in formation of hybrid material which activity depended on the DNA conditions. The assembling of the surface layer was confirmed by scanning electron microscopy and electrochemical impedance spectroscopy. The influence of DNA and pillar[5]arene on redox activity of polymeric dye was investigated and a significant increase of the peak currents was found for DNA damaged by reactive oxygen species generated by Cu2+/H2O2 mixture. Pillar[5]arene improves the electron exchange conditions and increases the response and its reproducibility. The applicability of the DNA sensor developed was shown on the example of ascorbic acid as antioxidant. It decreases the current in the concentration range from 1.0 µM to 1.0 mM. The possibility to detect antioxidant activity was qualitatively confirmed by testing tera infusion. The DNA sensor developed can find application in testing of carcinogenic species and searching for new antitumor drugs.


Assuntos
Dano ao DNA , DNA/análise , Espectroscopia Dielétrica/métodos , Compostos de Amônio Quaternário/química , Animais , Calixarenos , Cobre/química , Espectroscopia Dielétrica/instrumentação , Eletrodos , Peróxido de Hidrogênio/química , Ácidos Nucleicos Imobilizados/análise , Ácidos Nucleicos Imobilizados/química , Vermelho Neutro/química , Oxirredução , Polímeros/química , Compostos de Amônio Quaternário/análise
15.
J Pharm Biomed Anal ; 159: 224-228, 2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-29990889

RESUMO

Nowadays, parabens have been replaced by domiphen bromide, which is widely used in pharmaceutical and cosmetic products. The main aim of this study was to investigate stressed degradation products of domiphen bromide by mean of a rapid, specific and reliable LC-ESI MS/MS since phenyl bromination may occur due to the oxidation of bromide counter ion under oxidative conditions. LC-ESI-MS/MS have characterized a new compound, p-bromodomiphen, as the only degradation product and structure elucidation was also confirmed by the synthesis of the standard. Notably, the resulting p-bromodomiphen bromide is more stable then domiphen bromide in oxidizing conditions since no di-bromoderivatives were detected by MS studies; both domiphen and its p-bromo derivative were tested for antibacterial activity and were more effective on Gram positive (Staphylococcus aureus ATCC25923 and Bacillus cereus DSM31) compared to Gram negative bacteria (Escherichia coli ATCC25922 and Pseudomonas aeruginosa DSM22644). In conclusion, stressed degradation studies by LC-ESI-MS/MS have characterized a new compound that comprises an alternative to domiphen bromide since its antimicrobial activity is comparable to, if not better than, the parental compound.


Assuntos
Anti-Infecciosos/análise , Anti-Infecciosos/metabolismo , Compostos de Amônio Quaternário/análise , Compostos de Amônio Quaternário/metabolismo , Espectrometria de Massas em Tandem/métodos , Anti-Infecciosos/farmacologia , Bacillus cereus/efeitos dos fármacos , Bacillus cereus/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Compostos de Amônio Quaternário/farmacologia , Espectrometria de Massas por Ionização por Electrospray/métodos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/metabolismo
16.
J AOAC Int ; 101(6): 1873-1880, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29852893

RESUMO

Background: A flow-injection MS (FI/MS) method was evaluated for the quantitation of quaternary ammonium cations (QACs) in simple food simulants. Methods: The calibration standard was dimethyldioctadecyl ammonium ion (C18-C18), and the internal standard was benzyldimethylhexadecyl (BDMHD) ammonium ion. Calibration standards based on the C18-C18 ion were prepared in ethanol with a range of 5 to 500 ppb and contained 100 ppb BDMHD. The mobile phase was 90 + 10 (v/v) acetonitrile-5 mM aqueous ammonium acetate and flowed directly into an electrospray source of the mass spectrometer. Detection was accomplished by single ion recording (SIR) in positive mode. Results: Calibration curves were linear with coefficients of determination above 0.995, and the LOQ was 5 ppb. Recoveries of four QACs derived from Arquad 2HT-75, a commercially available surfactant, were measured in common food simulants: ethanol, water, 10% (v/v) ethanol in water, and 3% (v/v) aqueous acetic acid. A solvent exchange procedure was employed for the three aqueous solvents, which included complete evaporation of the sample followed by reconstitution in ethanol prior to injection. The solvent exchange method minimized losses because of QAC adsorption on glass surfaces. Recoveries ranged from 74.4 ± 4.0 to 106.7 ± 6.6% for the two most abundant Arquad 2HT-75 component cations, dimethyldioctadecyl ammonium and dimethyloctadecyl-hexadecyl ammonium. Conclusions: This method is suitable to quantify trace levels of QACs in food simulants as part of exposure evaluations related to their use in emerging food contact materials.


Assuntos
Espectrometria de Massas/métodos , Compostos de Amônio Quaternário/análise , Ácido Acético/química , Calibragem , Etanol/química , Água/química
17.
Methods Mol Biol ; 1789: 55-63, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29916071

RESUMO

In plant cells, vacuoles are extremely important for growth and development, and influence important cellular functions as photosynthesis, respiration, and transpiration. Plant cells contain lytic and storage vacuoles, whose size can be different depending on cell type and tissue developmental stage. One of the main roles of vacuoles is to regulate the cell turgor in response to different stimuli. Thus, studying the morphology, dynamics, and physiology of vacuole is fundamentally important to advance knowledge in plant cell biology at large. The availability of fluorescent probes allows marking vacuoles in multiple ways. These may be fast, when using commercially available chemical dyes, or relatively slow, in the case of specific genetically encoded markers based on proteins directed either to the membrane of the vacuole (tonoplast) or to the vacuole lumen. Any of these approaches provides useful information about the morphology and physiology of the vacuole.


Assuntos
Proteínas de Arabidopsis/análise , Arabidopsis/citologia , Corantes Fluorescentes/análise , Microscopia Confocal/métodos , Coloração e Rotulagem/métodos , Vacúolos/ultraestrutura , Arabidopsis/química , Arabidopsis/ultraestrutura , Proteínas Luminescentes/análise , Vermelho Neutro/análise , Compostos de Piridínio/análise , Compostos de Amônio Quaternário/análise , Vacúolos/química
18.
Methods Mol Biol ; 1789: 81-99, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29916073

RESUMO

The isolation of vacuoles is an essential step to unravel the important and complex functions of this organelle in plant physiology. Here, we describe a method for the isolation of vacuoles from Catharanthus roseus leaves involving a simple procedure for the isolation of protoplasts, and the application of a controlled osmotic/thermal shock to the naked cells, leading to the release of intact vacuoles, which are subsequently purified by density gradient centrifugation. The purity of the isolated intact vacuoles is assayed by microscopy, western blotting, and measurement of vacuolar (V)-H+-ATPase hydrolytic activity. Finally, membrane functionality and integrity is evaluated by measuring the generation of a transtonoplast pH gradient by the V-H+-ATPase and the V-H+-pyrophosphatase, also producing further information on vacuole purity.


Assuntos
Catharanthus/citologia , Fracionamento Celular/métodos , Folhas de Planta/citologia , Vacúolos/metabolismo , Vacúolos/ultraestrutura , Benzenossulfonatos/análise , Western Blotting/métodos , Catharanthus/metabolismo , Ensaios Enzimáticos/métodos , Fluoresceínas/análise , Corantes Fluorescentes/análise , Hidrólise , Microscopia de Fluorescência/métodos , Vermelho Neutro/análise , Imagem Óptica/métodos , Pressão Osmótica , Folhas de Planta/metabolismo , Proteínas de Plantas/análise , Proteínas de Plantas/metabolismo , Plantas Medicinais/citologia , Plantas Medicinais/metabolismo , Protoplastos/citologia , Protoplastos/metabolismo , Protoplastos/ultraestrutura , Compostos de Piridínio/análise , Compostos de Amônio Quaternário/análise , Coloração e Rotulagem/métodos , ATPases Vacuolares Próton-Translocadoras/análise , ATPases Vacuolares Próton-Translocadoras/metabolismo
19.
Methods Mol Biol ; 1789: 101-115, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29916074

RESUMO

A series of optimized protocols to isolate vacuoles from both yeast and plant cells, and to characterize the purified organelles at a functional and structural level, are described. For this purpose, we took advantage of the combined use of cell fractionation techniques with different fluorescence-based approaches namely flow cytometry, fluorescence microscopy and spectrofluorimetry. These protocols altogether constitute valuable tools for the study of vacuole structure and function, as well as for the high-throughput screening of drug libraries to identify new molecules that target the vacuole.


Assuntos
Fracionamento Celular/métodos , Citometria de Fluxo/métodos , Microscopia de Fluorescência/métodos , Vacúolos/metabolismo , Vacúolos/ultraestrutura , Vitis/citologia , Leveduras/citologia , Laranja Acridina/análise , Compostos de Anilina/análise , Barbitúricos/análise , Cálcio/análise , Cálcio/metabolismo , Corantes Fluorescentes/análise , Isoxazóis/análise , Vermelho Neutro/análise , Compostos de Piridínio/análise , Compostos de Amônio Quaternário/análise , Coloração e Rotulagem/métodos , ATPases Vacuolares Próton-Translocadoras/análise , ATPases Vacuolares Próton-Translocadoras/metabolismo , Vacúolos/química , Vacúolos/enzimologia , Vitis/química , Vitis/enzimologia , Vitis/metabolismo , Xantenos/análise , Leveduras/química , Leveduras/enzimologia , Leveduras/metabolismo
20.
Methods Mol Biol ; 1789: 143-154, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29916077

RESUMO

Chemical compounds are useful to perturb biological functions in the same way as classical genetic approaches take advantage of mutations at the DNA level to perturb gene function. The use of bioactive chemicals currently called chemical genetic is especially valuable for cell biology. Chemical genetic approaches allow perturbations of cellular processes post-germination in a given time window controlling the severity of the effect by modifying or modulating the dose and/or the period of the treatment. Additionally, compounds can be applied directly to different mutants and translational fluorescent reporters/marker lines, expanding the repertoire of experimental setups addressing cell biology research. In this chapter, we describe standard protocols to visualize vacuole morphology and trafficking to the vacuole and the use of bioactive compounds as a proxy to study these biological processes.


Assuntos
Arabidopsis/ultraestrutura , Microscopia Confocal/métodos , Vacúolos/ultraestrutura , Arabidopsis/efeitos dos fármacos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/análise , Proteínas de Arabidopsis/metabolismo , Técnicas de Cultura de Células/métodos , Endocitose/efeitos dos fármacos , Indicadores e Reagentes , Microscopia de Fluorescência/métodos , Transporte Proteico/efeitos dos fármacos , Compostos de Piridínio/análise , Compostos de Piridínio/metabolismo , Compostos de Amônio Quaternário/análise , Compostos de Amônio Quaternário/metabolismo , Esterilização/métodos , Vacúolos/efeitos dos fármacos , Vacúolos/metabolismo
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