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1.
Water Res ; 216: 118278, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35366494

RESUMO

Cethyltrimethylammonium chloride (CTMA) is one of the most used quaternary ammonium compounds (QACs) in consumer products. CTMA and other QACs are only partially eliminated in municipal wastewater treatment and they can interact with bacteria in biological processes. Currently, there is only limited information on the antimicrobial efficiency of CTMA in matrices other than standard growth media and if and how CTMA influences conventional chemical disinfection. The results obtained in this study showed that the susceptibility of E. coli to CTMA was significantly enhanced in phosphate-buffered saline, lake water and wastewater compared to broth. In broth, a minimum inhibitory concentration (MIC) of CTMA of 20 mgL-1 was observed for E. coli, whereas a 4-log inactivation occurred for CTMA concentrations of about 4 mgL-1 in buffered ultra-purified water, a lake water and wastewater effluent. The impacts of the pre-exposure and the presence of CTMA on inactivation by ozone and monochloramine were tested with three different E. coli strains: AG100 with the efflux pump acrAB intact, AG100A with it deleted and AG100tet with it overexpressed. Pre-exposure of E. coli AG100 to CTMA led to an increased susceptibility for ozone with second-order inactivation rate constants (∼ 106 M-1s-1) increasing by a factor of about 1.5. An opposite trend was observed for monochloramine with second-order inactivation rate constants (∼ 103 M-1s-1) decreasing by a factor of about 2. For E. coli AG100tet, the second-order inactivation rate constant decreased by a factor of almost 2 and increased by a factor of about 1.5 for ozone and monochloramine, respectively, relative to the strain AG100. The simultaneous presence of CTMA and ozone enhanced the second-order inactivation rate constants for CTMA concentrations of 2.5 mgL-1 by a factor of about 3. For monochloramine also an enhancement of the inactivation was observed, which was at least additive but might also be synergistic. Enhancement by factors from about 2 to 4.5 were observed for CTMA concentrations > 2.5 mgL-1.


Assuntos
Ozônio , Purificação da Água , Compostos de Bis-Trimetilamônio , Cetrimônio/farmacologia , Cloraminas , Desinfecção/métodos , Escherichia coli , Cinética , Ozônio/química , Águas Residuárias , Água/farmacologia , Purificação da Água/métodos
2.
J Photochem Photobiol B ; 209: 111939, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32640366

RESUMO

Despite progress in the development and application of novel therapeutic agents, cancer remains a major cause of death worldwide. Therefore, there is a need for new approaches to increase therapeutic options and efficiency. The metabolism of cancer cells differs from that of non-malignant cells and their mitochondria show altered activities that can be utilized as a target for drug development. Salt 1 is a low-molecular weight heterocyclic compound of the polymethine class that accumulates in the mitochondria of cancer cells and selectively disrupts their metabolism. Salt 1 leads to a non-apoptotic form of cell death in vitro that is associated with an autophagic cellular response and eventual metabolic collapse, and inhibits human tumor xenograft growth in vivo without apparent toxicity for normal cells. As a pentamethinium compound, salt 1 exhibits intrinsic fluorescence and is a candidate for photosensitization after excitation by appropriate wavelengths of light. Herein, we report that salt 1 is a potent photosensitizer, which generates a photodynamic effect and provides enhanced cytotoxicity compared to salt 1 without light exposure. Importantly, photosensitization is optimally induced by red light, which is used clinically for photosensitization and penetrates further into tissues than lower wavelengths. Cancer cells treated with non-cytotoxic doses of salt 1 and subsequently exposed to 630 nm light show severely damaged mitochondria, manifested by reduced mitochondrial membrane potential and disintegration of the mitochondrial tubular network. As a consequence, cancer cells lose their proliferative potential and die via apoptosis in the presence of light. These findings indicate that salt 1 is a promising photosensitizer with potential to be combined with 630 nm light to strengthen its efficacy in cancer therapy.


Assuntos
Apoptose/efeitos dos fármacos , Compostos de Bis-Trimetilamônio/farmacologia , Mitocôndrias/efeitos dos fármacos , Fármacos Fotossensibilizantes/farmacologia , Linhagem Celular Tumoral , Humanos , Mitocôndrias/fisiologia , Fotoquimioterapia , Espécies Reativas de Oxigênio/metabolismo , Sais/química
3.
Int J Cosmet Sci ; 42(3): 259-269, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32037558

RESUMO

OBJECTIVES: The main objective of this paper was to optimize hair conditioner performance through variation of composition utilizing automated cosmetic formulation platform and advanced characterization techniques as well as develop understanding of how performance (wet combing and wet lubrication) of hair conditioner is affected by its rheology (i.e. yield stress) and controlled breakdown of the formulations (dilution). The experimental results show that yield stress greatly impacts rheology, stability and performance of the lamellar gels for hair conditioning. METHODS: All samples were prepared on the Chemspeed Flex Formax. A mechanical rheometer was used to measure bulk viscosity and yield stress in each sample. Dia-stron tensile tester was used to measure the lamellar gels ability to reduce combing force. Potential stronger lamellar gel network formation in the formed lamellar gels potentially leads to higher yield stress exhibited. Viscosity values were also measured after a controlled breakdown (i.e. dilution) of each sample. This was also carried out using a mechanical rheometer. RESULTS: Yield stress of the formulations was engineered through composition variation and was recorded in each system. The highest yield stress value is 251.179 Pa at a BTAC/CA ratio of 6:10, and the lowest yield stress is 50.14 Pa at a BTAC/CA ratio of 6:5. The highest yield stress value is 50.14 Pa at a CTAC/CA ratio of 6:10, and the lowest yield stress is 19.98 Pa at a CTAC/CA ratio of 2:10. The highest overall yield stress values can also be observed in the BTAC/CA system, whereas the CTAC/CA system has relatively lower yield stress values. Dilution of each formulation caused a breakdown in viscosity of each formulation with the formulations with highest yield stress maintaining higher viscosity than the other formulations. The formulations with highest yield stress in each system which also maintains the highest dilution viscosity (6% BTAC/10% CA and 6% CTAC/10% CA) have the best effect on reducing overall combing force, that is from dry hair tress to wet hair tress and after product is rinsed off. At a BTAC/CA system of ratio 6:5, there is an 89% reduction in combing force and a 95% reduction in combing force in the BTAC/CA system of ratio 6:10. At a CTAC/CA system of ratio 2:10, there is a 65% reduction in combing force and a 88% reduction in combing force in the CTAC/CA system of ratio 6:10. A 'conditioned' soft feel was observed on each hair tress as the sample was applied and after it was rinsed off. CONCLUSIONS: The overall performance of the lamellar gels for hair conditioning can be engineered through optimization of the formulation microstructure and formulation microstructure breakdown on dilution.


OBJECTIF: L'objectif principal de ce document est d'optimiser les performances des après-shampooing grâce à la variation de sa composition en utilisant une plateforme de formulation cosmétique automatisée et des techniques de caractérisation avancées, ainsi qu'en comprenant mieux comment les performances (peignage humide et lubrification humide) de l'après-shampooing sont affectées par sa rhéologie (c.-à-d. limite élastique) et répartition contrôlée des formulations (dilution). Les résultats expérimentaux montrent que la limite d'élasticité a un impact important sur la rhéologie, la stabilité et les performances des gels lamellaires pour le conditionnement des cheveux. MÉTHODÉS: Tous les échantillons ont été préparés sur le Chemspeed Flex Formax. Un rhéomètre mécanique a été utilisé pour mesurer la viscosité en vrac et la limite élastique dans chaque échantillon. Un testeur de traction Dia-stron a été utilisé pour mesurer la capacité des gels lamellaires à réduire la force de peignage. La formation d'un réseau de gel lamellaire potentiellement plus fort dans les gels lamellaires formés conduit potentiellement à une limite d'élasticité plus élevée. Les valeurs de viscosité ont également été mesurées après une dilution de chaque échantillon. Cela a également été réalisé à l'aide d'un rhéomètre mécanique. RÉSULTATS: La limite d'élasticité des formulations a été modifiée par variation de la composition et a été enregistrée dans chaque système. La limite d'élasticité la plus élevée est de 251,179 Pa à un rapport BTAC/CA de 6,10 et la limite d'élasticité la plus basse est 50,14 Pa à un rapport BTAC/CA de 6: 5. La valeur de limite d'élasticité la plus élevée est de 50,14 Pa à un rapport CTAC/CA de 6,10 et la contrainte d'élasticité la plus basse est de 19,98 Pa à un rapport CTAC/CA de 2:10. Les valeurs globales de contrainte d'écoulement les plus élevées peuvent également être observées dans le système BTAC/CA tandis que le système CTAC/CA a des valeurs de contrainte d'écoulement relativement plus faibles. La dilution de chaque formulation a provoqué une dégradation de la viscosité de chaque formulation, les formulations ayant la limite d'élasticité la plus élevée conservant une viscosité plus élevée que les autres formulations. Les formulations avec la limite d'élasticité la plus élevée dans chaque système qui maintient également la viscosité de dilution la plus élevée (6% BTAC/10% CA et 6% CTAC/10% CA) a le meilleur effet sur la réduction de la force de peignage globale, c'est-à-dire des cheveux secs aux cheveux mouillés tressées et après que le produit soit rincé. Dans un système BTAC/CA de rapport 6: 5, il y a une réduction de 89% de la force de peignage et une réduction de 95% de la force de peignage dans le système BTAC/CA de rapport 6:10. Dans un système CTAC/CA de rapport 2:10, il y a une réduction de 65% de la force de peignage et une réduction de 88% de la force de peignage dans le système CTAC/CA de rapport 6:10. Une sensation de douceur a été observée sur chaque tresse lors de l'application de l'échantillon et après le rinçage. CONCLUSION: Les performances globales des gels lamellaires pour le conditionnement des cheveux peuvent être conçues par l'optimisation de la microstructure de formulation et la décomposition de la microstructure de formulation lors de la dilution.


Assuntos
Compostos de Bis-Trimetilamônio/química , Géis/química , Preparações para Cabelo , Compostos de Amônio Quaternário/química , Reologia , Tensoativos/química , Automação , Micelas , Resistência à Tração
4.
Biosens Bioelectron ; 138: 111308, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31103013

RESUMO

Poly(ADP-ribose) polymerase-1 (PARP-1), as an original tumor marker, has aroused wide attention in recent years. However, only a few researches have been done for PARP-1 activity detection because PARP-1 is lack of optical or electrochemical property. In this work, a label-free and high-sensitive photoelectrochemical (PEC) biosensor for PARP-1 activity detection based on poly[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorenylene phenylene (PFP) has been designed. To the best of our knowledge, it is the first time that PEC has been used to monitor PARP-1 activity. PARP-1 were activated under the function of activated dsDNA, as a result, branched polymers of ADP-ribose (PAR) with plentiful negative charge were formed in the presence of nicotinamide adenine dinucleotide (NAD+). Subsequently, positively charged PFP with good photoelectrochemical properties, were absorbed on PAR via electrostatic interaction. High photocurrent was produced under light induction, which was depended on the PARP-1 activity. The biosensor has a wide linear range from 0.01 to 2 U with a detection limit of 0.007 U. The strategy has been applied in breast and ovarian cancer cells to detection PARP-1 activity with approving results, which signifies that it is a promising tool for clinical diagnosis.


Assuntos
Biomarcadores Tumorais/metabolismo , Técnicas Biossensoriais , Compostos de Bis-Trimetilamônio/química , Poli(ADP-Ribose) Polimerase-1/metabolismo , Linhagem Celular Tumoral , Técnicas Eletroquímicas , Eletrodos , Ensaios Enzimáticos/métodos , Humanos , Indóis/farmacologia , Limite de Detecção , NAD/farmacologia , Processos Fotoquímicos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Eletricidade Estática
5.
Chemistry ; 25(36): 8522-8527, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-30947361

RESUMO

One of the challenges for fluorescent sensors is to reduce their target environment size from a micrometer scale, such as biological cells, to a nanometer scale. Proton maps near membranes are of importance in bioenergetics and are the first goal in nanometer-scale analysis with fluorescent sensors. Thirty-three fluorescent photoinduced-electron-transfer pH sensors bearing an environment-sensitive benzofurazan fluorophore and having different hydrophobicity/hydrophilicity and hydrogen-bonding abilities were prepared. These sensors were scattered in nanospaces associated with anionic and cationic micelles as model membranes to indicate proton availability and polarity in local spaces. Gathering the data from the sensors allowed the successful drawing of proton maps near anionic and cationic micelles, in which electrostatic attraction/repulsion of protons by the charged head groups of micelles and dielectric suppression of protons were clearly observed.


Assuntos
Corantes Fluorescentes/química , Micelas , Compostos de Bis-Trimetilamônio/química , Transporte de Elétrons , Concentração de Íons de Hidrogênio , Prótons , Dodecilsulfato de Sódio/química , Espectrometria de Fluorescência
6.
Colloids Surf B Biointerfaces ; 180: 23-30, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31022554

RESUMO

For miltefosine (MIL), a zwitterionic alkylphospholipid approved for leishmaniasis treatment, the mechanism of action is not well established. Electron paramagnetic resonance (EPR) spectroscopy has indicated that the interaction of MIL with membrane proteins has similarities to that of ionic surfactants. A general concern about leishmanicides is their high hemolytic potential, so we decided to compare the interactions of MIL and three ionic surfactants with the erythrocyte membrane. Measurements with two different spin labels indicated that the surfactants sodium dodecyl sulfate (SDS, anionic), cetyltrimethylammonium chloride (CTAC, cationic) and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS, zwitterionic) as well as MIL increase the dynamics of erythrocyte membrane proteins in a concentration-dependent manner. SDS produced the smallest increases in protein dynamics and was also the least hemolytic for measurements in PBS and in whole blood. Spin label EPR measurements performed directly in the blood plasma detected increased albumin stiffness caused by 2.5 mM SDS due to electrostatic/hydrophobic interactions. For 10 mM concentrations of the compounds, the EPR spectra showed a fraction of albumin with greater mobility and another with the same as that of the untreated plasma. The zwitterionic compounds MIL and HPS did not present significant differences in this study.


Assuntos
Antiprotozoários/farmacologia , Membrana Eritrocítica/efeitos dos fármacos , Proteínas de Membrana/química , Fosforilcolina/análogos & derivados , Animais , Antiprotozoários/química , Compostos de Bis-Trimetilamônio/química , Compostos de Bis-Trimetilamônio/farmacologia , Bovinos , Relação Dose-Resposta a Droga , Espectroscopia de Ressonância de Spin Eletrônica , Membrana Eritrocítica/química , Hemólise/efeitos dos fármacos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Micelas , Fosforilcolina/química , Fosforilcolina/farmacologia , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/farmacologia , Soroalbumina Bovina/química , Dodecilsulfato de Sódio/química , Dodecilsulfato de Sódio/farmacologia , Marcadores de Spin , Eletricidade Estática
7.
Chemosphere ; 223: 659-667, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30802831

RESUMO

Oxygen evolution complex (OEC) in photosystem II (PSII) is sensitive to environmental stressors. However, oxidative damage mechanism in PSII-OEC is still unclear. Here, we investigated photosynthetic performance of PSII, oxidative stress and antioxidant reaction induced by reactive oxygen species (ROS) in a unicellular green alga Chlorella vulgaris (C. vulgaris) under the stress of cetyltrimethylammonium chloride (CTAC). From the changes of chlorophyll fluorescence parameters and PSII activity, it was proved that the electron transport, which occurred initially at the electron donor side of OEC, was disturbed by CTAC. Moreover, a significant decrease of the oxygen evolution rate in OEC (40.95%) while an increase of ROS (50.50%) was obtained after the exposure to 0.6 mg/L CTAC compared to the control (without CTAC), confirming that more oxygen transferred to ROS under the stress. Furthermore, the increased ROS in chloroplast and the structural destruction in thylakoid membrane were observed, respectively. These results proved that oxidative damage mechanism in PSII-OEC is mainly through the reduction of oxygen evolution and the production of excessive ROS, thus leading to the destruction of OEC performance and chloroplast structure.


Assuntos
Compostos de Bis-Trimetilamônio/toxicidade , Chlorella vulgaris/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Oxigênio/química , Complexo de Proteína do Fotossistema II/química , Transporte de Elétrons , Complexo de Proteína do Fotossistema II/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tilacoides/ultraestrutura
8.
ACS Infect Dis ; 4(10): 1468-1474, 2018 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-30067012

RESUMO

A series of vancomycin derivatives alkylated at the N-terminus amine were synthesized, including those that contain quaternary trimethylammonium salts either directly at the terminal amine site or with an intervening three-carbon spacer. The examination of their properties provides important comparisons with a C-terminus trimethylammonium salt modification that we recently found to improve the antimicrobial potency of vancomycin analogues through an added mechanism of action. The N-terminus modifications disclosed herein were well-tolerated, minimally altering model ligand binding affinities (d-Ala-d-Ala) and antimicrobial activity, but did not induce membrane permeabilization that was observed with a similar C-terminus modification. The results indicate that our earlier observations with the C-terminus modification are sensitive to the site as well as structure of the trimethylammonium salt modification and are not simply the result of nonspecific effects derived from introduction of a cationic charge.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Vancomicina/química , Vancomicina/farmacologia , Alquilação , Antibacterianos/síntese química , Anti-Infecciosos/farmacologia , Compostos de Bis-Trimetilamônio/química , Permeabilidade da Membrana Celular/efeitos dos fármacos , Glicopeptídeos/química , Glicopeptídeos/farmacologia , Humanos , Ligantes , Ligação Proteica , Vancomicina/análogos & derivados , Vancomicina/síntese química
9.
Anal Sci ; 34(7): 777-782, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29998958

RESUMO

A highly sensitive flow-injection (FI) method was developed for the determination of ascorbic acid using chemiluminescence (CL) based detection. This method involved the following processes: (1) reduction of tetrachloroaurate(III) in hydrochloric acid with ascorbic acid; (2) on-line extraction of the residual Au(III) with rhodamine B from the aqueous hydrochloric acid solution into toluene, followed by the separation of the Au(III)-containing organic phase from the aqueous phase through a microporous Teflon membrane in the flow system; and (3) the measurement of CL produced in a flow cell upon mixing of the extract stream of Au(III) in toluene with luminol in the reversed micellar medium of cetyltrimethylammonium chloride-water in 1-hexanol-cyclohexane, which was injected into a CL reagent stream. In this procedure, a reduction in the CL intensity occurred due to the addition of ascorbic acid to the Au(III) solution. The CL signal of Au(III) decreased with increasing concentration of ascorbic acid in the aqueous sample solution. The proposed procedure allowed the indirect quantitative determination of ascorbic acid in the range of 1.0 × 10-12 to 1.0 × 10-7 M with a correlation coefficient of 0.987 and relative standard deviation of 2.1% (n = 6) at 1.0 × 10-9 M. The proposed FI-CL methodology was successfully applied for quantitative determination of ascorbic acid in fruit juices and pharmaceutical samples.


Assuntos
Ácido Ascórbico/análise , Compostos de Bis-Trimetilamônio/química , Análise de Injeção de Fluxo , Sucos de Frutas e Vegetais/análise , Luminescência , Preparações Farmacêuticas/análise , Medições Luminescentes , Micelas
10.
Colloids Surf B Biointerfaces ; 161: 555-562, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29145103

RESUMO

The stability of Chlorophyll a in water during prolonged exposure, at room temperature, to a neon lamp has been investigated by means of UV-vis and fluorescence spectroscopies. In addition, the Chlorophyll a (photo)stability evaluation in presence of suitable carriers has been performed in order to investigate its reactivity under the same conditions, for possible and future applications in Antimicrobial Photodynamic Therapy. Cetyltrimethylammonium chloride was chosen to solubilize Chlorophyll a in water. While, cetyltrimethylammonium chloride-capped gold nanoparticles offer a great opportunity because combine the Chlorophyll a action, used as a photosensitizer in Antimicrobial Photodynamic Therapy, with gold nanoparticles effect used in photothermal therapy. Indeed, the latter ones have exhibited an interesting rise of temperature if irradiated with visible light. Overall, both examined systems, cetyltrimethylammonium chloride/Chlorophyll a and gold nanoparticles/Chlorophyll a, were able to induce the Reactive Oxygen Species formation fundamental for a potential application in Antimicrobial Photodynamic Therapy.


Assuntos
Compostos de Bis-Trimetilamônio/química , Clorofila/química , Portadores de Fármacos/química , Ouro/química , Nanopartículas/química , Água/química , Clorofila/administração & dosagem , Clorofila A , Luz , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/química , Espécies Reativas de Oxigênio/química , Espectrometria de Fluorescência , Espectrofotometria
11.
Electrophoresis ; 38(13-14): 1724-1729, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28418580

RESUMO

We have recently demonstrated the separation of neutral and water-insoluble linear synthetic polymers in nonaqueous capillary zone electrophoresis (NACZE) using a cationic surfactant of cetyltrimethylammonium chloride (CTAC). In this study, eight ionic surfactants were investigated for the separation of four synthetic polymers (polystyrene, polymethylmethacrylates, polybutadiene, and polycarbonate); only three surfactants (CTAC, dimethyldioctadecylammonium bromide, and sodium dodecylsulfate) caused their separation. The order of the interaction between the polymers and the surfactants depended on both the surfactant species and the composition of the electrophoretic medium. Their investigation revealed that the separation is majorly affected by the hydrophobic interactions between the polymers and the ionic surfactants. In addition, the electrophoretic behavior of polycarbonate suggested that electrostatic interaction also affects the selectivity of the polymers.


Assuntos
Eletroforese Capilar/métodos , Polímeros/química , Polímeros/isolamento & purificação , Tensoativos/química , Ânions/química , Compostos de Bis-Trimetilamônio/química , Interações Hidrofóbicas e Hidrofílicas
12.
J Agric Food Chem ; 65(2): 260-269, 2017 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-27997185

RESUMO

In the framework of this study a synthesis methodology and characterization of long alkyl herbicidal ionic liquids (HILs) based on four commonly used herbicides (2,4-D, MCPA, MCPP, and dicamba) are presented. New HILs were obtained with high efficiency (>95%) using an acid-base reaction between herbicidal acids and hexadecyltrimethylammonium, octadecyltrimethylammonium, and behenyltrimethylammonium hydroxides in alcoholic medium. Among all synthesized salts, only three compounds comprising the MCPP anion were liquids at room temperature. Subsequently, the influence of both the alkyl chain length and the anion structure on their physicochemical properties (thermal decomposition profiles, solubility in 10 representative solvents, surface activity, density, viscosity, and refractive index) was determined. All HILs exhibited high thermal stability as well as surface activity; however, their solubility notably depended on both the length of the carbon chain and the structure of the anion. The herbicidal efficacy of the obtained salts was tested in greenhouse and field experiments. Greenhouse testing performed on common lambsquarters (Chenopodium album L.) and flixweed (Descurainia sophia L.) as test plants indicated that HILs were characterized by similar or higher efficacy compared to commercial herbicides. The results of field trials confirmed the high activity of HILs, particularly those containing phenoxyacids as anions (MCPA, 2,4-D, and MCPP).


Assuntos
Herbicidas/química , Herbicidas/farmacologia , Líquidos Iônicos/química , Ácido 2,4-Diclorofenoxiacético/química , Ácido 2-Metil-4-clorofenoxiacético/química , Compostos de Bis-Trimetilamônio/química , Brassicaceae/efeitos dos fármacos , Técnicas de Química Sintética , Chenopodium album/efeitos dos fármacos , Dicamba/química , Herbicidas/síntese química , Líquidos Iônicos/síntese química , Líquidos Iônicos/farmacologia , Plantas Daninhas/efeitos dos fármacos , Polônia , Solubilidade , Relação Estrutura-Atividade , Propriedades de Superfície , Viscosidade
13.
Int J Biol Macromol ; 92: 670-681, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27456123

RESUMO

Glossoscolex paulistus hemoglobin (HbGp) is an oligomeric multisubunit protein with molecular mass of 3600kDa. In the current study, the interaction of sodium dodecyl sulfate (SDS) and cetyl trimethylammonium chloride (CTAC) surfactants with the monomer d and the whole oxy-HbGp, at pH 7.0, was investigated. For pure monomer d solution, SDS promotes the dimerization of subunit d, and the monomeric and dimeric forms have sedimentation coefficient values, s20,w, around 2.1-2.4 S and 2.9-3.2 S, respectively. Analytical ultracentrifugation (AUC) and isothermal titration calorimetry (ITC) data suggest that up to 26 DS- anions are bound to the monomer. In the presence of CTAC, only the monomeric form is observed in solution for subunit d. For the oxy-HbGp, SDS induces the dissociation into smaller subunits, such as, monomer d, trimer abc, and tetramer abcd, and unfolding without promoting the protein aggregation. On the other hand, lower CTAC concentration promotes protein aggregation, mainly of trimer, while higher concentration induces the unfolding of dissociated species. Our study provides strong evidence that surfactant effects upon the HbGp-subunits are different, and depend on the surfactant: protein concentration ratio and the charges of surfactant headgroups.


Assuntos
Hemoglobinas/metabolismo , Oligoquetos/metabolismo , Tensoativos/metabolismo , Animais , Área Sob a Curva , Compostos de Bis-Trimetilamônio/metabolismo , Calorimetria , Difusão Dinâmica da Luz , Hidrodinâmica , Íons , Modelos Moleculares , Ligação Proteica , Dodecilsulfato de Sódio/metabolismo , Soluções , Ultracentrifugação
14.
Environ Sci Pollut Res Int ; 23(18): 18552-63, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27294701

RESUMO

This study investigated the treatment performance for aging leachate containing refractory organic pollutants by TiO2-organobentonite photocatalyst combined with polyaluminum chloride (PAC) coagulant. TiO2 was immobilized on organobentonite granules as a supporter modified by cetyltrimethylammonium chloride (CTAC). The prepared catalysts were characterized by ESEM, FTIR, and XRD analysis, which showed that TiO2-organobentonite catalyst had uniform coating of TiO2 on support. Chemical oxygen demand (COD) and NH3-N removal rates by combination of TiO2-CTAC2.0 photocatalysis and PAC coagulation were evaluated, optimized, and compared to that by either treatment alone, with respect to TiO2-CTAC2.0 dose, photocatalytic contact time, pH, and PAC dose. Furthermore, higher removal rates (COD 80 %; NH3-N 46 %) were achieved by response surface methodology (RSM) when TiO2-CTAC2.0 photocatalysis was followed by PAC coagulation at optimized conditions. The optimized experimental conditions were TiO2-CTAC2.0 dosage of 5.09 g/L, at pH 5.53, photocatalytic contact time for 180 min, and PAC dosage of 1062 mg/L.


Assuntos
Compostos de Bis-Trimetilamônio/química , Eliminação de Resíduos/métodos , Titânio/química , Poluentes Químicos da Água/química , Hidróxido de Alumínio/análise , Bentonita/química , Análise da Demanda Biológica de Oxigênio , Compostos de Bis-Trimetilamônio/análise , Catálise , Cetrimônio , Compostos de Cetrimônio , Coagulantes , Poluentes Químicos da Água/análise
15.
Analyst ; 141(3): 1017-26, 2016 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-26730682

RESUMO

The study of molecular adsorption on solid surfaces is of broad interest. However, so far the study has been restricted to idealized flat smooth rigid surfaces which are rarely the case in real world applications. Here we describe a study of molecular adsorption on a complex surface of the submicron fibers of a fibrous membrane of regenerated cellulose in aqueous media. We use a cationic surfactant, cetyltrimethylammonium chloride (CTAC), as the adsorbing molecule. We study the equilibrium adsorption of CTAC molecules on the same area of the fibers by sequentially immersing the membrane in pure water, 1 mM and then a 20 mM solution of CTAC. Atomic force microscopy (AFM) is applied to study the adsorption. The force-volume mode is used to record the force-deformation curves of the adsorbed molecules on the fiber surface. We suggest a model to separate the forces due to the adsorbed molecules from the elastic deformation of the fiber. Interestingly, knowledge of the surface geometry is not required in this model provided the surface is made of elastically homogeneous material. Different models are investigated to estimate the amount of the adsorbed molecules based on the obtained force curves. The exponential steric repulsion model fits the force data the best. The amount of the adsorbed surfactant molecules and its dependence on the concentration are found to be reasonable compared to the data previously measured by means of Raman scattering done on a flat surface of silica.


Assuntos
Compostos de Bis-Trimetilamônio/química , Microscopia de Força Atômica , Tensoativos/química , Adsorção , Membranas Artificiais , Dióxido de Silício/química , Propriedades de Superfície , Água/química
16.
Electrophoresis ; 36(7-8): 1016-23, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25641038

RESUMO

We recently introduced a pressure-assisted sweeping-reversed migration-EKC (RM-EKC) method for preconcentration of neutral polar N-nitrosamines with low affinity for the micellar phase. The type of surfactant and phase ratio are dominant factors in dictating the magnitude of interactions between analyte and micellar phase, thus four surfactants (anionic and cationic) with a range of functionalities (SDS, ammonium perfluorooctanoate (APFO), bile salts, and cetyltrimethylammonium chloride (CTAC)) were evaluated for sweeping-RM-EKC of highly polar N-nitrosamines. All gave acceptable results for sweeping-RM-EKC when used in high concentrations (≥200 mM) with low EOF. While no single surfactant was superior by all measures, all but the bile salts had useful performance characteristics. APFO showed the narrowest peak widths and highest number of theoretical plates, though two species co-migrated at all concentrations (25-300 mM); SDS and the cationic surfactant CTAC also showed good separation characteristics and could resolve all peaks, but CTAC had wider separation window. Various types of capillaries coated for EOF control were compared for use with anionic and cationic surfactants. A commercial zero-EOF capillary coated with a polymer bearing sulfonic acid functional groups showed superior EOF suppression and reproducibility of migration time with all surfactants.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Eletroforese Capilar/métodos , Nitrosaminas/análise , Tensoativos/química , Compostos de Bis-Trimetilamônio/química , Nitrosaminas/química , Pressão , Reprodutibilidade dos Testes
17.
J Phys Chem B ; 119(1): 179-91, 2015 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-25490177

RESUMO

Micelles formed by amphiphiles in a protic ionic liquid (PIL), ethylammonium nitrate (EAN), were investigated using synchrotron small-angle X-ray scattering and contrasted with those that formed in water. The amphiphiles studied were cationic hexadecyltrimethylammonium chloride (CTAC) and hexadecylpyridinium bromide (HDPB) and nonionic poly(oxyethylene) (10) oleyl ether (Brij 97) and Pluronic ethylene oxide-propylene oxide-ethylene oxide block copolymer (P123). The scattering patterns were analyzed using spherical, core-shell, and cylindrical scattering models. The apparent micelle shape and size of the surfactants and the block copolymer in the PIL have been reported. At low amphiphile concentrations (<10 wt %) spherical micelles were preferentially formed for all the amphiphiles in EAN. The micelles formed by the two cationic amphiphiles in EAN and water were similar, though different scattering models were required predominantly due to the ionic nature of EAN. The two nonionic amphiphiles formed micelles with similar core radii in water and in EAN. However, the micelle shells composed of ethylene oxide groups fitted to a significantly thicker layer in water compared to EAN. At high concentrations (>10 wt %) in EAN and water, there was a preference for cylindrical micelles for CTAC, HDPB, and Brij 97; however, the P123 micelles remained spherical.


Assuntos
Líquidos Iônicos/química , Compostos de Amônio Quaternário/química , Tensoativos/química , Água/química , Compostos de Bis-Trimetilamônio/química , Micelas , Estrutura Molecular , Óleos de Plantas/química , Poloxaleno/química , Polietilenoglicóis/química , Compostos de Piridínio/química , Espalhamento a Baixo Ângulo , Síncrotrons
18.
J Phys Chem B ; 118(29): 8652-61, 2014 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-25000531

RESUMO

The interaction of three dicationic (gemini) surfactants-3,3'-[1,6-(2,5-dioxahexane)]bis(1-dodecylimidazolium) chloride (oxyC2), 3,3'-[1,16-(2,15-dioxahexadecane)]bis(1-dodecylimidazolium) chloride (oxyC12), and 1,4-bis(butane)imidazole-1-yl-3-dodecylimidazolium chloride (C4)--with bovine serum albumin (BSA) has been studied by the use of small-angle X-ray scattering (SAXS), circular dichroism (CD), and (1)H nuclear magnetic resonance diffusometry. The results of CD studies show that the conformation of BSA was changed dramatically in the presence of all studied surfactants. The greater decrease (from 56 to 24%) in the α-helical structure of BSA was observed for oxyC2 surfactant. The radii of gyration estimated from SAXS data varied between 3 and 26 nm for the BSA/oxyC2 and BSA/oxyC12 systems. The hydrodynamic radius of the BSA/surfactant system estimated from NMR diffusometry varies between 5 and 11 nm for BSA/oxyC2 and 5 and 8 nm for BSA/oxyC12.


Assuntos
Compostos de Bis-Trimetilamônio/química , Dicroísmo Circular , Espalhamento a Baixo Ângulo , Soroalbumina Bovina/química , Tensoativos/química , Síncrotrons , Difração de Raios X , Animais , Bovinos , Difusão , Espectroscopia de Ressonância Magnética , Ligação Proteica , Estrutura Secundária de Proteína , Rotação
19.
Colloids Surf B Biointerfaces ; 118: 14-24, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24717174

RESUMO

Glossoscolex paulistus (HbGp) hemoglobin is an oligomeric protein, displaying a quaternary structure constituted by 144 globin and 36 non-globin chains (named linkers) with a total molecular mass of 3.6MDa. CTAC effects on the oxy-HbGp thermal stability were investigated, by DLS and SAXS, at pH 5.0, 7.0 and 9.0. DLS data show that the oxy-HbGp-CTAC interactions induce a significant decrease of the protein thermal stability, with the formation of larger aggregates, at pH 5.0 and 7.0. In the acidic pH, oxy-HbGp 0.5mg/mL, undergoes a partial oligomeric dissociation, on going from 0.2 to 0.6mmol/L of CTAC, accompanied by a decrease in the Dh values from 27±1 to 22±1nm. It is observed, for the first time, that in the absence and in the presence of CTAC, oxy-HbGp undergoes a partial oligomeric dissociation, with increase of temperature, before denaturation and aggregation at pH values 7.0 and 5.0. SAXS data show that oxy-HbGp undergoes denaturation at 60°C, in the presence of CTAC, pH 5.0. At neutral pH 7.0, the aggregation process starts at 20°C, with increase of Rg and Dmax parameters. At both pH values, 5.0 and 7.0, the denaturation and aggregation are accompanied by the sedimentation of the aggregates. At pH 9.0, oxy-HbGp is totally dissociated at 40°C, in the presence of 0.2mmol/L of CTAC, while in the presence of 0.4mmol/L of surfactant the aggregation process starts at 20°C, with the full denaturation of protein at higher temperature. Finally, our data show, for the first time, that the oligomeric dissociation is an important step in the thermal denaturation of oxy-HbGp, in the presence of CTAC, independently of both the pH and the protein concentration.


Assuntos
Compostos de Bis-Trimetilamônio/farmacologia , Luz , Oligoquetos/química , Oxiemoglobinas/química , Espalhamento a Baixo Ângulo , Temperatura , Difração de Raios X , Animais , Hidrodinâmica , Concentração de Íons de Hidrogênio , Modelos Moleculares , Tamanho da Partícula , Estabilidade Proteica/efeitos dos fármacos
20.
Chemosphere ; 96: 39-45, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24001670

RESUMO

This study investigates the effect of sodium nitroprussiate (SNP), an exogenous NO-donor, on the joint toxicity of binary mixtures of cetyltrimethylammonium chloride (CTAC) and fluoranthene (Flu) (CTAC/Flu), which are representatives for surfactants and polycyclic aromatic hydrocarbons (PAHs) respectively, in a unicellular green alga Chlorella vulgaris (C. vulgaris). The results showed that the addition of low SNP (20µM) alleviated the CTAC/Flu combined pollution damage in C. vulgaris. Supplement of low SNP significantly increased the algae biomass, chlorophyll content, soluble protein content and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) as compared to CTAC/Flu treatment alone. SNP also reduced the content of malondialdehyde (MDA) and the reactive oxygen species (ROS), as compared with CTAC/Flu treated alone. On the contrary, the above phenomena were reversed when high concentration of SNP (100µM) was added. Our study indicated that the damage of the joint action of surfactants and PAHs on hydrobios can be alleviated through protecting against oxidant substances and increasing the activity of antioxidant enzymes with an exogenous supply of NO in certain concentration range.


Assuntos
Compostos de Bis-Trimetilamônio/toxicidade , Chlorella vulgaris/efeitos dos fármacos , Fluorenos/toxicidade , Óxido Nítrico/metabolismo , Tensoativos/toxicidade , Poluentes Químicos da Água/toxicidade , Catalase/metabolismo , Chlorella vulgaris/enzimologia , Chlorella vulgaris/metabolismo , Clorofila/metabolismo , Malondialdeído/metabolismo , Peroxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
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