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1.
Nihon Yakurigaku Zasshi ; 154(3): 115-120, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31527360

RESUMO

More than twenty years have passed since the demonstration of hydrogen sulfide (H2S) as a signaling molecule. Various roles of this molecule have been reported including neuromodulation, vascular relaxation, cytoprotection, anti-inflammation, and oxygen sensing. During the study of its effect on neuromodulation, we found TRP channels as a target of H2S, and later identified polysulfides (H2Sn) as chemical entity of the ligand. We found that H2S relaxes vasculatures in synergy with NO, and recently identified H2Sn as products produced by the chemical interaction between H2S and NO to exert the effect, suggesting that it may be a mechanism for the synergy between the two molecules. It has attracted attention that sulfite, a further metabolite of H2S and H2Sn, protects neurons from oxidative stress by a mechanism different from that by H2S and H2Sn.


Assuntos
Sulfeto de Hidrogênio/química , Transdução de Sinais , Sulfetos/química , Sulfitos/química , Humanos , Óxido Nítrico/química , Vasodilatadores/química
2.
Ecotoxicol Environ Saf ; 182: 109443, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31398782

RESUMO

The continuous presence of toxic elements in the aquatic environments around mine tailings occurs due to bioleaching or chemical extraction promoted by the mining operations. Biogenic passivation treatment of tailings dams can be a new environment-friendly technique to inhibit the solubility of heavy metals. In spite of current bioleaching researches, we tried to minimize the mobility of the trace elements in the laboratory scale through the formation of a passivation layer in the presence of a mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The X-ray diffraction (XRD) and scanning electron microscope (SEM) represented the jarosite generation as an inhibitory layer on the mineral surfaces of the tested materials. More detailed observations on electron probe micro-analyzer (EPMA) showed the co-precipitation of metals with the passivation layer. Thereby, the passivation layer demonstrates potential in elements immobilization which, in turn, can be optimized in the natural systems. Our working hypothesis was to exploit and optimize the formation of the passivation layer to maximize the immobilization of heavy metals (e.g., Cu, Cr). The optimization process of bioleaching experiments using indigenous bacteria caused a reduced solubility for Cu (from around 20% to 4.5%) and Cr (from around 30% to 10.6%) and the formation of 6.5 gr passivation layer. The analyses finally represented the high efficiency of the passivation technique to minimize metals bioleaching in comparison to earlier studies.


Assuntos
Metais Pesados/química , Mineração , Sulfetos/química , Poluentes Químicos da Água/química , Acidithiobacillus , Acidithiobacillus thiooxidans , Bactérias , Biodegradação Ambiental , Compostos Férricos , Metais Pesados/análise , Minerais , Solubilidade , Sulfatos , Sulfetos/análise , Poluentes Químicos da Água/análise
3.
Anal Bioanal Chem ; 411(21): 5437-5444, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31300858

RESUMO

To meet the need for high-throughput immunoassays, many multiplex fluorescent immunoassays have been proposed. Most of them need different kinds of fluorescent label indicators during the test. In this work, a novel indirect ELISA-inspired dual-channel fluorescent immunoassay based on 3-mercaptopropionic acid capped CdTe/ZnS quantum dots (QDs) was constructed. The ELISA wells were coated with two kinds of antigen-QD complex. When the primary antibodies were present in a sample, they mediated the binding of a secondary antibody-DNA-gold nanoparticle complex to the antigen-QD complex. Then the gold nanoparticles quenched the fluorescence of the QDs and a decrease in fluorescence intensity was observed. Thus, the amount of primary antibody could be estimated from the decrease of fluorescence intensity. Owing to the wide absorption range and the relatively narrow emission band of the QDs, the dual-channel fluorescent immunoassay system could work at the same excitation wavelength and the emission wavelengths of each channel had no interference. As a result, two different kinds of primary antibody could be detected at the same time in one ELISA well, which simplified the operation and greatly improved the efficiency. Besides, only one type of secondary antibody needs to be added to the prepared microtiter plates, which further simplified the operation during the detection procedure. This dual-channel fluorescent immunoassay system will provide new insights into high-throughput immunodetection. Graphical abstract.


Assuntos
Compostos de Cádmio/química , Ensaio de Imunoadsorção Enzimática/métodos , Imunofluorescência/métodos , Pontos Quânticos , Sulfetos/química , Telúrio/química , Compostos de Zinco/química , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão
5.
Phys Chem Chem Phys ; 21(29): 15988-16004, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31297500

RESUMO

S-Sulfhydration of cysteine to the Cys-SSH persulfide is an oxidative post-translational modification that plays an important regulatory role in many physiological systems. Though hydrogen persulfide (H2S2) has recently been established as a signaling and cellular sulfhydration reagent, the chemistry and chemical biology of persulfides remain poorly explored. We first report an extensive high-level ab initio quantum chemical investigation of (H2S2)n, (H2S2)m·H2O, and (H2O)m·H2S2 clusters (n = 1-3 and m = 1, 2) and of H2S2 complexes with 19 compounds that model the side chains of naturally-occurring amino acids. The high polarizability of S necessitates the use of large, very diffuse, basis sets for proper description of H2S2 and its complexes. H2S2 possesses a skewed equilibrium geometry, with nonpolar trans and more polar cis conformers 6 and 8 kcal mol-1 higher in energy, respectively; the skewed conformation is preserved in all neutral and cationic complexes while a cis geometry prevails in some anionic complexes. H2S2 is found to be a better H-bond donor and a poorer acceptor than H2S, and that in complexes with H2O, alcohols and amines, H2S2 is a better H-bond donor. Radical delocalization on both S atoms stabilizes the perthiyl (HSS˙) over the thiyl (HS˙) radical and results in a ∼20 kcal mol-1 lower S-H homolytic bond dissociation in H2S2, making it a potential antioxidant. A simple additive model is optimized for H2S2 and used together with the TIP3P model and the CHARMM36 all-atom force field (FF) to investigate the structure and thermodynamic properties of liquid H2S2 and the solubility of H2S2 in water, and to model H2S2-protein interactions (for which new FF parameters are further developed). Very weak H-bonding characterizes liquid H2S2 and it is found immiscible in liquid water with a trend in H-bonding strengths between H2S2 and H2O in the order O-HO ≫ S-HO > O-HS. This work does not only provide a thorough description of the structure and energetics of H2S2 and its various complexes, but also yields a reliable FF for investigating H2S2 in chemistry and biology.


Assuntos
Simulação por Computador , Modelos Químicos , Sulfetos/química , Hidrogênio/química , Ligações de Hidrogênio , Termodinâmica
6.
Nature ; 571(7766): 546-549, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31292542

RESUMO

Amide bond formation is one of the most important reactions in both chemistry and biology1-4, but there is currently no chemical method of achieving α-peptide ligation in water that tolerates all of the 20 proteinogenic amino acids at the peptide ligation site. The universal genetic code establishes that the biological role of peptides predates life's last universal common ancestor and that peptides played an essential part in the origins of life5-9. The essential role of sulfur in the citric acid cycle, non-ribosomal peptide synthesis and polyketide biosynthesis point towards thioester-dependent peptide ligations preceding RNA-dependent protein synthesis during the evolution of life5,9-13. However, a robust mechanism for aminoacyl thioester formation has not been demonstrated13. Here we report a chemoselective, high-yielding α-aminonitrile ligation that exploits only prebiotically plausible molecules-hydrogen sulfide, thioacetate12,14 and ferricyanide12,14-17 or cyanoacetylene8,14-to yield α-peptides in water. The ligation is extremely selective for α-aminonitrile coupling and tolerates all of the 20 proteinogenic amino acid residues. Two essential features enable peptide ligation in water: the reactivity and pKaH of α-aminonitriles makes them compatible with ligation at neutral pH and N-acylation stabilizes the peptide product and activates the peptide precursor to (biomimetic) N-to-C peptide ligation. Our model unites prebiotic aminonitrile synthesis and biological α-peptides, suggesting that short N-acyl peptide nitriles were plausible substrates during early evolution.


Assuntos
Evolução Química , Nitrilos/química , Nitrilos/síntese química , Origem da Vida , Peptídeos/química , Peptídeos/síntese química , Água/química , Acetileno/análogos & derivados , Acetileno/química , Dipeptídeos/síntese química , Dipeptídeos/química , Ferricianetos/química , Sulfeto de Hidrogênio/química , Concentração de Íons de Hidrogênio , Oxirredução , Compostos de Sulfidrila/química , Sulfetos/química
7.
Chemosphere ; 233: 946-953, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340422

RESUMO

Scorodite is an important mineral not only for arsenic (As) removal from industrial wastewaters but also in the mobility and final fate of As in waste rocks, contaminated soils and sediments, and mine tailings. Because of the mineral's high As-loading capacity and stability, numerous studies have been done to understand its formation. Unfortunately, most of these studies were limited to elevated temperatures (>70 °C), so the processes involved in scorodite formation under ambient conditions remain unclear. This study provides evidence of the catalytic effects of hematite on the formation of scorodite at 25 °C in a pyrite-rich natural geologic material. Scorodite peaks were detected in the XRD patterns of the leaching residues with and without hematite, but those in the former were stronger and more pronounced than the latter. These results suggest that the formation of scorodite was catalysed by hematite, a generalisation that is further supported by strong characteristic IR absorption bands of scorodite at 819 cm-1 (As-O bending vibration), 785 and 725 cm-1 (As-O stretching vibrations), and 2990 cm-1 (OH-vibration) as well as the distinct XPS binding energies of Fe(III)-As (709.7 eV), As(V)-O (44.8, 44.31 and 43.7 eV), O2- (530.5 eV) and coordinated water (531.3 eV) in scorodite. This phenomenon could be attributed to three possible mechanisms: (1) more rapid precipitation promoted by the "seeding" effect of hematite particles, (2) additional supply of Fe3+ from hematite dissolution under acidic conditions, and (3) enhanced oxidations of Fe2+ to Fe3+ and As(III) to As(V) on the surface of hematite.


Assuntos
Arsênico/química , Arsenicais/síntese química , Compostos Férricos/química , Águas Residuárias/química , Purificação da Água/métodos , Catálise , Ferro/química , Oxirredução , Poluentes do Solo/análise , Sulfetos/química , Poluentes Químicos da Água/análise
8.
Chemosphere ; 233: 252-260, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31176126

RESUMO

Although 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane (DDT) was banned in the United States in 1972, it is still often detected in sediments where pyrogenic carbonaceous matter (PCM) and sulfate-reducing bacteria (SRB) co-exist. In this study, we found that 70.2 ±â€¯0.2% of DDT disappeared in the presence of SRB and graphite powder, a model PCM, after 21 days at pH 7. Our results suggest that the observed DDT decay was due to the reaction between graphite powder and the reduced sulfur species that were produced by SRB. No biofilm formation was observed on the surface of graphite powder. Rather, the activity of SRB was inhibited by the presence of graphite powder. To understand the involvement of PCM in DDT decay, electrochemical cells and batch reactor experiments with sulfur-pretreated PCM as well as direct electrochemical reduction by a potentiostat were employed. Our results suggest that polysulfide, sulfide, sulfite, and thiosulfate could all react with PCM, forming surface-bound intermediates that subsequently led to DDT decay. The reactivity of reduced sulfur species was the highest for polysulfide, followed by sulfide, sulfite, and thiosulfate.


Assuntos
DDT/química , DDT/metabolismo , Desulfovibrio/metabolismo , Biodegradação Ambiental , Poluentes Ambientais/química , Poluentes Ambientais/metabolismo , Grafite , Sulfetos/química , Sulfetos/metabolismo , Sulfitos/química , Sulfitos/metabolismo , Tiossulfatos/química , Tiossulfatos/metabolismo
9.
Anal Bioanal Chem ; 411(20): 5277-5285, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161325

RESUMO

Rapid, highly sensitive detection of tau protein and other neurodegenerative biomarkers remains a significant hurdle for diagnostic tests for Alzheimer's disease. In this work, we developed a novel tyrosinase (TYR)-induced tau aptamer-tau-tau antibody (anti-tau) sandwich fluorescence immunoassay to detect tau protein that used dopamine (DA)-functionalized CuInS2/ZnS quantum dots as the fluorophore. CuInS2/ZnS core/shell quantum dots with high luminescence, low toxicity, and excellent biocompatibility were successfully fabricated and decorated with DA through amide conjugation. Meanwhile, TYR was conjugated with anti-tau by a click reaction. When DA-functionalized CuInS2/ZnS quantum dots were added to the sandwich system, TYR catalyzed the transformation of DA to dopamine quinone, which acted as an effective electron acceptor and triggered fluorescence quenching. The fluorescence intensity of the immunoassay based on DA-functionalized CuInS2/ZnS quantum dots shows good performance in terms of linearity with the logarithm of tau protein concentration, with a linear concentration range from 10 pM to 200 nM. This work is the first to use a TYR-induced fluorescence immunoassay for the rapid detection of tau protein, paving a new way for the detection of disease biomarkers. Graphical abstract.


Assuntos
Cobre/química , Imunofluorescência/métodos , Índio/química , Monofenol Mono-Oxigenase/química , Pontos Quânticos/química , Selênio/química , Sulfetos/química , Compostos de Zinco/química , Proteínas tau/análise , Cristalografia por Raios X , Dopamina/análogos & derivados , Dopamina/química , Microscopia Eletrônica de Transmissão , Análise Espectral/métodos
10.
Talanta ; 202: 230-236, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171175

RESUMO

Rapid and non-destructive detection of circulating tumor cells (CTCs) with no disruption of their functions is of great significance for clinical tumor therapy. However, many existing methods for CTC detection commonly rely on conventional three-color immunofluorescence identification, which damages CTCs and easily causes loss of cells. Here, we employed a method to simultaneously capture and authenticate CTCs based on immunonanocomposites (ZnS:Mn2+ QDs and Fe3O4/SiO2) equipped with permanent fluorescent and magnetic properties. A multifunctional nanocomposite was synthesized by encapsulating ZnS:Mn2+ quantum dots (QDs) and Fe3O4 nanoparticles into SiO2 nanospheres and bio-conjugating tumor-specific anti-EpCAM antibodies onto the surface. The resulting nanocomposite had a high tumor cell binding ability, and the Fe3O4 nanoparticles had a rapid magnetic response that enabled capture of circulating tumor cells from patients' blood within minutes. In addition, the cell-immunonanocomposites complexes could be directly recognized by the yellow-orange light emitted by the ZnS:Mn2+ quantum dots, thus labeling cells without utilizing the complicated and destructive procedures involved in traditional CTCs identification. We successfully achieved a high capture efficiency of up to 90.8%, and the specific fluorescence labeling of CTCs was realized in 9 clinical breast cancer patients' samples. Furthermore, this simple, convenient and cell-friendly approach is significant for solving the problems of cell viability and enables non-destructive CTC detection, which marks an advance in cancer treatment and clinical applications.


Assuntos
Nanopartículas de Magnetita/química , Manganês/química , Células Neoplásicas Circulantes/patologia , Pontos Quânticos/química , Sulfetos/química , Compostos de Zinco/química , Linhagem Celular , Humanos , Tamanho da Partícula , Propriedades de Superfície
11.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1122-1123: 58-63, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31153132

RESUMO

Imrecoxib is a specific inhibitor of cyclooxygenase-2. Its hydroxymethyl (M1) and carboxylic acid (M2) metabolites are the major circulating components in human plasma. It has been demonstrated that the anti-inflammatory activities of M1 and M2 are both equal to the parent drug. In the current study, a highly sensitive and rapid method was established and validated for the determination of imrecoxib, M1 and M2 in human plasma via liquid chromatography-tandem mass spectrometry technique. To our knowledge, this is the first study that simultaneously analyzed imrecoxib and its two active metabolites following a rapid protein-precipitation clean-up. Imrecoxib and its metabolites were separated on a reversed-C18 column (3.5 µm; 100 × 4.6 mm), and the mobile phase was optimized as 5 mM ammonium acetate: acetonitrile: formic acid (35: 65: 0.1, v/v/v), based on the pKa values of analytes. Mass spectrometric detection was conducted in a positive multiple reaction monitoring mode. The m/z transitions of imrecoxib (370.2 → 278.2), M1 (386.2 → 278.2) and M2 (400.2 → 236.2) were selected for an effective balance between sensitivity and selectivity. An excellent linearity was demonstrated over the concentration ranges of 0.100-40.0, 0.200-80.0 and 2.00-800 ng/mL for imrecoxib, M1 and M2, respectively. The method validation was carried out in agreement with the FDA guidance. Furthermore, the pharmacokinetic properties of imrecoxib and its two active metabolites were characterized in patients with moderate hepatic impairment, by using the developed and validated method.


Assuntos
Cromatografia Líquida/métodos , Pirróis , Sulfetos , Espectrometria de Massas em Tandem/métodos , Humanos , Limite de Detecção , Modelos Lineares , Hepatopatias , Pirróis/sangue , Pirróis/química , Pirróis/farmacocinética , Reprodutibilidade dos Testes , Sulfetos/sangue , Sulfetos/química , Sulfetos/farmacocinética
12.
Inorg Chem ; 58(16): 10501-10507, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31247870

RESUMO

Zinc thiolate bonds are intriguing targets of study because of their redox noninnocence and prevalence in bioinorganic sites. A five-coordinate zinc dithiolate complex [Et4N]2[LZn] (H4L = N,N'-di(2-sulfhydrylphenyl)-pyridine-2,6-dicarboxamide) was synthesized to study the oxidative reactivity of zinc thiolate bonds. Multiple chemically reversible reactions of the zinc thiolate bonds were identified. Oxidation of [Et4N]2[LZn] with iodine resulted in structural rearrangement to a bimetallic disulfide-bridged complex. In contrast, the addition of elemental sulfur to [Et4N]2[LZn] resulted in the insertion of a neutral S3 fragment into the Zn-thiolate bond to selectively form an unusual monometallic tetrasulfanido complex. When oxidized, this tetrasulfanido compound rearranged to form a bimetallic trisulfide-bridged complex. The observed diversity of zinc thiolate reactivity, particularly with sulfur, is likely important in biological contexts.


Assuntos
Complexos de Coordenação/química , Compostos de Sulfidrila/química , Sulfetos/química , Enxofre/química , Zinco/química , Modelos Moleculares , Estrutura Molecular , Oxirredução
13.
Chemosphere ; 233: 744-753, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31200134

RESUMO

In this study, the enhanced effect of pyrite (FeS2) on zero-valent iron (Fe0) corrosion for arsenic (As) removal was investigated in a combined-Fe0/FeS2 system. The effects of different Fe0/FeS2 composition, dosage and initial pH were evaluated by batch experiments. Results showed that the best combination ratio of Fe0:FeS2 (w/w) was 1:1 and the optimal dosage of mixture was 2.0 g/L. The combination of Fe0 and FeS2 in a system significantly enhanced the reactivity of Fe0 for effective As removal within a broad pH range (3.0-9.0). The effective As removal in the combined-Fe0/FeS2 system was primarily ascribed to being enhanced corrosion of Fe0 by addition of FeS2. SEM and XRD characterizations strongly verified this point. Specifically, the mechanism study (the releases of Fe2+ and total Fe ion, variations of pH values as well as XPS characterization) suggested that FeS2 in the combined-Fe0/FeS2 system could alleviate the passivation of Fe0 (pHini 3.0-5.0) and accelerate the dissolution of pristine oxide film that coated on Fe0 surface (pHini 6.8-9.0). Besides, FeS2 in combined-Fe0/FeS2 system could also accelerate the reactions between Fe0 to O2 at pHini 3.0-9.0. These phenomena were well explained by a galvanic couple between Fe0 and FeS2, where FeS2 was a cathode and Fe0 was an anode. Consequently, electrons released from Fe0 that mediated by FeS2 to oxide film, passivation layer and O2 were accelerated in combined-Fe0/FeS2 system and thereby enhanced the corrosion of Fe0 for efficient As removal. Our findings suggest that utilizing FeS2 to enhance the corrosion of Fe0 would be a promising technology for remediation of As-contaminated water.


Assuntos
Arsênico/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Arsênico/química , Corrosão , Ferro/química , Sulfetos/química , Água , Poluentes Químicos da Água/química
14.
Talanta ; 201: 309-316, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122428

RESUMO

Two different colors of water-soluble core-shell quantum dots CdTe/CdS (green and orange red) have been synthesized and characterized in this paper. The formation of core-shell quantum dots not only improves the fluorescence quantum yield, but also reduces the biological toxicity of quantum dots, and improves the fluorescence lifetime. Two novel fluorescent bioprobes, CdTe/CdS (λem = 545 nm)-5-Fu and Bio-CdTe/CdS (λem = 600 nm)-TAM, have been synthesized via the interaction of these two core-shell quantum dots with anticancer drugs (5-Fu) and P-gp inhibitors (TAM), respectively. These two fluorescent probes have been simultaneously used in fluorescence imaging of human breast cancer cells MDA-MB-231/MDR. It can be observed that under the action of P-gp inhibitors distributed on the cell membrane, anticancer drugs can be retained in cancer cells. According to the color of quantum dots on the probe, the visualization results of the action of anticancer drugs and P-gp inhibitors can be obtained. This study shows that to prepare functional bioprobes using core-shell quantum dots CdTe/CdS has great potential in the field of biomedical research such as anticancer drugs.


Assuntos
Antineoplásicos/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Corantes Fluorescentes/química , Pontos Quânticos/química , Subfamília B de Transportador de Cassetes de Ligação de ATP/antagonistas & inibidores , Cádmio/química , Cádmio/toxicidade , Compostos de Cádmio/química , Compostos de Cádmio/toxicidade , Linhagem Celular Tumoral , Fluorescência , Corantes Fluorescentes/toxicidade , Fluoruracila/farmacologia , Humanos , Pontos Quânticos/toxicidade , Solubilidade , Espectrometria de Fluorescência/métodos , Sulfetos/química , Sulfetos/toxicidade , Tamoxifeno/farmacologia , Telúrio/química , Telúrio/toxicidade , Água/química
15.
Anticancer Res ; 39(5): 2369-2375, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31092429

RESUMO

BACKGROUND/AIM: Benzo[a]pyrene (BaP), an environmental pollutant produced by combustion processes, induces expression of cytochrome P450 (CYP) 1A1 via the activation of aryl hydrocarbon receptor (AHR). Induced CYP1A1 is involved in BaP metabolism, resulting in either detoxification or metabolic activation in a context-dependent manner. The effect of diallyl trisulfide (DATS), a garlic-derived organosulfur compound, on BaP metabolism has not been investigated. MATERIALS AND METHODS: The combined effect of DATS and BaP on BaP metabolism in hepatocyte-derived HepG2 cells was examined. RESULTS: DATS enhanced BaP-induced CYP1A1 and CYP1B1 mRNA expression, BaP hydroxylation and BaP-DNA adduct formation. Combined treatment of BaP and DATS also increased reactive oxygen species levels. DATS enhanced BaP-induced AHR recruitment and histone H3 acetylation on the CYP1A1 promoter. CONCLUSION: DATS combined treatment enhances BaP metabolic activation through an AHR-modulating mechanism.


Assuntos
Compostos Alílicos/farmacologia , Benzo(a)pireno/farmacologia , Citocromo P-450 CYP1A1/genética , Receptores de Hidrocarboneto Arílico/genética , Sulfetos/farmacologia , Ativação Metabólica/efeitos dos fármacos , Compostos Alílicos/química , Adutos de DNA/efeitos dos fármacos , Adutos de DNA/genética , Alho/química , Regulação da Expressão Gênica/efeitos dos fármacos , Células Hep G2 , Humanos , Espécies Reativas de Oxigênio/metabolismo , Sulfetos/química
16.
Ultrason Sonochem ; 56: 378-385, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31101276

RESUMO

Herein, novel manganese sulfide nanoparticles (MnS NPs) decorated reduced graphene oxide (rGOS) nanocomposite have been designed through a facile ultrasound-assisted method and followed by a sonication process. After then, as-synthesized α-MnS@rGOS was characterized by HRTEM, FESEM, XPS, XRD and EIS. Furthermore, the α-MnS@rGOS nanocomposite modified SPCE (screen-printed carbon electrode) shows excellent electrochemical sensing performance towards Parkinson's disease biomarker of dopamine (DA). Moreover, the fabricated sensor showed a wide linear range for dopamine between 0.02 and 438.6 µM and nanomolar detection limit (3.5 nM). In addition, the α-MnS@rGOS modified SPCE showed selectivity towards the detection of dopamine in presence of a 10-fold higher concentration of other important biomolecules. The nanocomposite film modified SPCE sensor was good stable and reproducible towards the detection of Parkinson's disease biomarker. Furthermore, the as-synthesized α-MnS@rGOS nanocomposite modified SPCE has been applied to the determination of dopamine in human serum, rat serum and pharmaceutical samples with acceptable recoveries.


Assuntos
Dopamina/análise , Eletroquímica/métodos , Grafite/química , Compostos de Manganês/química , Nanopartículas/química , Óxidos/química , Sulfetos/química , Ondas Ultrassônicas , Biomarcadores/análise , Catálise , Técnicas de Química Sintética , Eletroquímica/instrumentação , Eletrodos , Concentração de Íons de Hidrogênio , Cinética , Compostos de Manganês/síntese química , Oxirredução , Doença de Parkinson , Sulfetos/síntese química
17.
Analyst ; 144(12): 3716-3720, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31134993

RESUMO

A photothermal immune-imaging assay was innovatively designed for the visual quantitative detection of cancer biomarkers by coupling CuxS nanocrystals with a portable infrared thermal imager on a smartphone. The rolling circle amplification (RCA) technique was used for the formation of a CuxS nanocrystal concatemer, thus opening up new territories in immunoassay development.


Assuntos
Biomarcadores Tumorais/análise , Imunoensaio/métodos , Nanocompostos/química , Antígeno Prostático Específico/análise , Smartphone , Anticorpos/imunologia , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Biomarcadores Tumorais/imunologia , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Cobre/química , DNA/química , DNA/genética , Humanos , Imunoensaio/instrumentação , Raios Infravermelhos , Masculino , Nanocompostos/efeitos da radiação , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico , Antígeno Prostático Específico/imunologia , Sulfetos/química , Temperatura Ambiente
18.
Chemosphere ; 230: 406-415, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31112863

RESUMO

Norfloxacin (NOR) is an emerging antibiotics contaminant due to its high resistance to microbial degradation and natural weathering. In this study, Fe-doped ZnS photocatalyst (Zn0.9Fe0.1S) was deposited on nickel foam (Ni-foam) to improve photocatalytic activity under visible light irradiation. The mass ratio of Zn0.9Fe0.1S and Ni-foam was optimized to be 0.03 g catalyst versus per g Ni-foam (0.03 Zn0.9Fe0.1S/Ni-foam), which led to the highest removal rate of 95%. The optimal degradation condition for NOR over 0.03 Zn0.9Fe0.1S/Ni-foam was pH at 7.0, initial NOR concentration of 5 mg L-1, and initial photocatalyst concentration of 11.7 g L-1, with the highest first-order reaction rate constant of 0.025 min-1 and mineralization rate of 63.1%. The NOR removal rate on 0.03 Zn0.9Fe0.1S/Ni-foam photocatalyst (95%) was approximately four times of that obtained on Zn0.9Fe0.1S photocatalyst (25%). The increased photocatalytic performance could be attributed to the function of Ni-foam as excellent electron collectors that provided efficient photoinduced charge separation from Zn0.9Fe0.1S. The reactive species responsible for the degradation of NOR were photo-generated holes, hydroxyl radical, and superoxide radicals. Nearly 90% of the photocatalytic efficiency was retained over seven cycles and the released metal ion concentrations were <0.3% of the total mass of photocatalyst, suggesting high stability of the photocatalyst during the photocatalytic reactions. The aqueous/solid mass transfer and intraparticle mass transfer for Zn0.9Fe0.1S/Ni-foam were not limiting factors for the degradation of NOR. Therefore the Zn0.9Fe0.1S/Ni-foam photocatalyst could be applied in the degradation of hazardous pollutants.


Assuntos
Ferro/química , Luz , Níquel/química , Norfloxacino/análise , Oxidantes Fotoquímicos/química , Sulfetos/química , Poluentes Químicos da Água/análise , Compostos de Zinco/química , Catálise , Norfloxacino/efeitos da radiação , Oxirredução , Poluentes Químicos da Água/efeitos da radiação
19.
Chemistry ; 25(39): 9191-9196, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31087690

RESUMO

Poly(amidoamine) dendrimers grafted on carbon nanotubes have been appended with iron(II)-α-keto acid (benzoylformate) complex of polypyridyl ligand to design artificial non-heme oxygenase model. This nano-enzyme was applied for selective catalytic oxidation of organic molecules. Although the carbon nanotubes serve as a robust heterogeneous platform, the amine terminals of dendrimers provide catalysts binding sites and the amide bonds provide a necessary second coordination sphere similar to the enzymatic polypeptide chains. Such a hybrid design prevented the deactivation of the primary active sites leading to 8 times faster oxidative decarboxylation rates than those of its homogeneous analogue. An electrophilic iron(IV)-oxo intermediate has been intercepted, which catalyzes the selective oxidation of alcohols to aldehydes and incorporates single oxygen atoms into sulfides and olefins by using aerial oxygen with multiple turnover numbers. The catalyst was consecutively regenerated three times by mild chemical treatment and showed negligible loss of activity.


Assuntos
Dendrímeros/química , Compostos Ferrosos/química , Cetoácidos/química , Nanotubos de Carbono/química , Catálise , Modelos Moleculares , Oxirredução , Oxigenases/química , Oxigenases/metabolismo , Sulfetos/química
20.
Int J Mol Sci ; 20(9)2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31071929

RESUMO

(1) The beneficial effects of hydrogen sulfide (H2S) on the cardiovascular and nervous system have recently been re-evaluated. It has been shown that lanthionine, a side product of H2S biosynthesis, previously used as a marker for H2S production, is dramatically increased in circulation in uremia, while H2S release is impaired. Thus, lanthionine could be classified as a novel uremic toxin. Our research was aimed at defining the mechanism(s) for lanthionine toxicity. (2) The effect of lanthionine on H2S release was tested by a novel lead acetate strip test (LAST) in EA.hy926 cell cultures. Effects of glutathione, as a redox agent, were assayed. Levels of sulfane sulfur were evaluated using the SSP4 probe and flow cytometry. Protein content and glutathionylation were analyzed by Western Blotting and immunoprecipitation, respectively. Gene expression and miRNA levels were assessed by qPCR. (3) We demonstrated that, in endothelial cells, lanthionine hampers H2S release; reduces protein content and glutathionylation of transsulfuration enzyme cystathionine-ß-synthase; modifies the expression of miR-200c and miR-423; lowers expression of vascular endothelial growth factor VEGF; increases Ca2+ levels. (4) Lanthionine-induced alterations in cell cultures, which involve both sulfur amino acid metabolism and calcium homeostasis, are consistent with uremic dysfunctional characteristics and further support the uremic toxin role of this amino acid.


Assuntos
Alanina/análogos & derivados , Cálcio/metabolismo , Insuficiência Renal Crônica/tratamento farmacológico , Sulfetos/farmacologia , Uremia/tratamento farmacológico , Alanina/química , Alanina/farmacologia , Aminoácidos Sulfúricos/efeitos dos fármacos , Aminoácidos Sulfúricos/metabolismo , Linhagem Celular , Cistationina beta-Sintase/genética , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Citometria de Fluxo , Regulação da Expressão Gênica/efeitos dos fármacos , Glutationa/metabolismo , Humanos , Sulfeto de Hidrogênio/metabolismo , MicroRNAs/genética , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/genética , Oxirredução , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/metabolismo , Sulfetos/química , Uremia/genética , Uremia/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética
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