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1.
J Chromatogr A ; 1644: 462090, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33823387

RESUMO

In this study, to selectively enrich N-glycans from complex biological samples, a novel Zr(IV) modified adenosine triphosphate (Zr(IV)-ATP) functionalized monolith was prepared through a facile approach. Well-defined macroporous structure was observed in the ATP functionalized monolith, which allows rapid mass transfer under low backpressure and is beneficial for the enrichment of N-glycans. After being modified with Zr(IV), the resulting Zr(IV)-ATP functionalized monolith could selectively capture N-glycans through the specific interactions between the sulfonate groups of 1-aminopyrene-3,6,8-trisulfonic acid (APTS) labeled N-glycans and Zr(IV). An APTS labeled maltooligosaccharide ladder was used to optimize the enrichment conditions for APTS labeled N-glycans, and capillary electrophoresis (CE) coupled with laser-induced fluorescence (LIF) detector was employed to evaluate the enrichment efficiency. The results show that the APTS labeled maltooligosaccharides could be enriched under the selected conditions and the signal amplify factors of the maltooligosaccharides were between 7.4 and 19.5 with RSDs for reproducibility from 4.0% to 8.3% (n = 3). Finally, the proposed method was successfully used for the enrichment and detection of N-glycans released from Ribonuclease B.


Assuntos
Trifosfato de Adenosina/química , Polissacarídeos/química , Zircônio/química , Eletroforese Capilar , Glucose/química , Oligossacarídeos/química , Polímeros/química , Pirenos/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
2.
Ecotoxicol Environ Saf ; 214: 112115, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33691242

RESUMO

Nanoplastics (NPs) are becoming an emerging pollutant of global concern. A potential risk of NPs is that they can serve as carriers and synergistically function with other contaminants to cause diseases. A variety of diseases such as Alzheimer's disease are related to the generation of amyloid fibrils, and insulin is typically used as a model to study the fibrillation process. In this study, we examined the fibrillation of insulin promoted by polystyrene nanoplastics (PSNPs) alone and synergistically with organic contaminants (denoted as X, X = pyrene, bisphenol A, 2,2',4,4'-tetrabromodiphenyl ether, 4,4'-dihydroxydiphenylmethane, or 4-nonylphenol) having different polarities using thioflavin T fluorescence assays, dynamic light scattering, and circular dichroism spectroscopy. The presence of PSNPs and small organic contaminants decreased the lag phase time (tlag) for insulin fibrillation from 54.6 h to 35-51 h and their combination (PS-X) enhanced this process (tlag = 21-30 h). Notably, the lag phase time for insulin fibrillation with PS-nonpolar contaminants, PS-weakly polar contaminants, and PS-polar contaminants is around 20.8, 26.7, and 30.1 h, respectively, indicating the synergistic effect of PS-nonpolar contaminants or PS-weakly polar contaminants was more obvious than that of PS-polar contaminants. Moreover, molecular dynamic simulation reveal the interactions between insulin and PSs or small organic contaminants are primarily driven by van der Waals forces and hydrophobic interactions. Overall, the findings of this study underscore the potentially significant environmental impact of small organic contaminants assisting NPs in promoting insulin fibrillation.


Assuntos
Poluentes Ambientais/química , Insulina/química , Microplásticos/química , Nanopartículas/química , Poliestirenos/química , Compostos Benzidrílicos/química , Éteres Difenil Halogenados/química , Fenóis/química , Pirenos/química
3.
Molecules ; 26(4)2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33669746

RESUMO

The new coordination polymers (CPs) [Zn(µ-1κO1:1κO2-L)(H2O)2]n·n(H2O) (1) and [Cd(µ4-1κO1O2:2κN:3,4κO3-L)(H2O)]n·n(H2O) (2) are reported, being prepared by the solvothermal reactions of 5-{(pyren-4-ylmethyl)amino}isophthalic acid (H2L) with Zn(NO3)2.6H2O or Cd(NO3)2.4H2O, respectively. They were synthesized in a basic ethanolic medium or a DMF:H2O mixture, respectively. These compounds were characterized by single-crystal X-ray diffraction, FTIR spectroscopy, thermogravimetric and elemental analysis. The single-crystal X-ray diffraction analysis revealed that compound 1 is a one dimensional linear coordination polymer, whereas 2 presents a two dimensional network. In both compounds, the coordinating ligand (L2-) is twisted due to the rotation of the pyrene ring around the CH2-NH bond. In compound 1, the Zn(II) metal ion has a tetrahedral geometry, whereas, in 2, the dinuclear [Cd2(COO)2] moiety acts as a secondary building unit and the Cd(II) ion possesses a distorted octahedral geometry. Recently, several CPs have been explored for the cyanosilylation reaction under conventional conditions, but microwave-assisted cyanosilylation of aldehydes catalyzed by CPs has not yet been well studied. Thus, we have tested the solvent-free microwave-assisted cyanosilylation reactions of different aldehydes, with trimethylsilyl cyanide, using our synthesized compounds, which behave as highly active heterogeneous catalysts. The coordination polymer 1 is more effective than 2, conceivably due to the higher Lewis acidity of the Zn(II) than the Cd(II) center and to a higher accessibility of the metal centers in the former framework. We have also checked the heterogeneity and recyclability of these coordination polymers, showing that they remain active at least after four recyclings.


Assuntos
Aldeídos/química , Cianetos/química , Micro-Ondas , Polímeros/química , Pirenos/química , Compostos de Trimetilsilil/química , Catálise , Ligação de Hidrogênio , Ligantes , Modelos Moleculares , Conformação Molecular , Polímeros/síntese química , Solventes , Termogravimetria
4.
Molecules ; 26(4)2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33673272

RESUMO

Selective recognition of nucleotides with synthetic receptors is an emerging direction to solve a series of nucleic acid-related challenges in biochemistry. Towards this goal, a new aza-cyclophane with two different dyes, naphthalimide and pyrene, connected through a triamine linker has been synthesized and studied for the ability to bind and detect nucleoside triphosphates in an aqueous solution. The receptor shows Foerster resonance energy transfer (FRET) in fluorescence spectra upon excitation in DMSO, which is diminished dramatically in the presence of water. According to binding studies, the receptor has a preference to bind ATP (adenosine triphosphate) and CTP (cytidine triphosphate) with a "turn-on" fluorescence response. Two separate emission bands of dyes allow one to detect nucleotides in a ratiometric manner in a broad concentration range of 10-5-10-3 M. Spectroscopic measurements and quantum chemical calculations suggest the formation of receptor-nucleotide complexes, which are stabilized by dispersion interactions between a nucleobase and dyes, while hydrogen bonding interactions of nucleobases with the amine linkers are responsible for selectivity.


Assuntos
Éteres Cíclicos/química , Naftalimidas/química , Nucleotídeos/química , Piperidinas/química , Pirenos/química , Trifosfato de Adenosina , Corantes Fluorescentes/química , Ligação de Hidrogênio , Estrutura Molecular , Soluções/química , Espectrometria de Fluorescência , Água/química
5.
Molecules ; 26(5)2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33670937

RESUMO

The new symmetric acyclic N,N'-bis(1-pyrenyl) squaramide (H2L) functionalized with the pyrene moiety as a fluorogenic fragment has been designed and its ability to selectively detect specific anions and metals investigated. H2L selectively binds Cl- both in solution (DMSO 0.5% H2O and MeCN) and in the solid state, and allows to selectively detect Cu2+ in MeCN with the formation of a 2:1 metal-receptor complex, with a green intense emission appreciable by naked eye under the UV lamp. The H2L copper complex preserves its emission properties in the presence of Cl-. The addition of basic anions (OH-, CN-, and F-) up to 10 equivalents caused the deprotonation of the squaramide NHs and a dramatic change of the emission properties of the H2L copper complex.


Assuntos
Complexos de Coordenação/química , Cobre/química , Pirenos/química , Quinina/análogos & derivados , Acetonitrilas/química , Ânions/química , Teoria da Densidade Funcional , Modelos Moleculares , Conformação Molecular , Quinina/química , Espectrometria de Fluorescência
6.
ACS Appl Mater Interfaces ; 13(7): 9134-9142, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33573369

RESUMO

Aromatic molecules such as pyrenes are a unique class of building units for graphene functionalization, forming highly ordered π-π stacks while peptides provide more complex, biocompatible linkers. Understanding the adsorption and stacking behavior of these molecules and their influence on material properties is an essential step in enabling highly repeatable 2D material-based applications, such as biosensors, gas sensors, and solar cells. In this work, we characterize pyrene and peptide self-assembly on graphene substrates using fluorescence microscopy, atomic force microscopy and electrolyte-gated field-effect measurements supported by quantum mechanical calculations. We find distinct binding and assembly modes for pyrenes versus peptides with corresponding distinct electronic signatures in their characteristic charge neutrality point and field-effect slope responses. Our data demonstrates that pyrene- and peptide-based self-assembly platforms can be highly beneficial for precisely customizing graphene electronic properties for desired device technologies such as transport-based biosensing graphene field-effect transistors.


Assuntos
Grafite/química , Peptídeos/química , Pirenos/química , Transistores Eletrônicos , Eletrólitos/química , Elétrons , Microscopia de Força Atômica , Microscopia de Fluorescência , Imagem Óptica , Tamanho da Partícula , Peptídeos/síntese química , Pirenos/síntese química , Propriedades de Superfície
7.
Chem Commun (Camb) ; 57(13): 1603-1606, 2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33463645

RESUMO

Herein, we have unravelled the key influence of aromatic interactions on the mechanistic pathways of peptide self-assembly by introducing suitable chromophores (pyrene vs. naphthalene). Although both self-assembled peptides are indistinguishable in their morphologies, this minor structural difference strongly affects the packing modes (parallel vs. antiparallel) and the corresponding self-assembly mechanism (cooperative vs. isodemsic).


Assuntos
Naftalenos/química , Peptídeos/química , Pirenos/química , Interações Hidrofóbicas e Hidrofílicas , Conformação Proteica
8.
Arch Biochem Biophys ; 699: 108748, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33444627

RESUMO

ApoA-I is the main protein of HDL which has anti-atherogenic properties attributed to reverse cholesterol transport. It shares with other exchangeable apolipoproteins a high level of structural plasticity. In the lipid-free state, the apolipoprotein amphipathic α-helices interact intra- and inter-molecularly, providing structural stabilization by a complex self-association mechanism. In this study, we employed a multi-parametric fluorescent probe to study the self-association of apoA-I. We constructed six single cysteine mutants spanning positions along three helices: F104C, K107C (H4), K133C, L137C (H5), F225C and K226C (H10); and labelled them with N-Maleimide Pyrene. Taking advantage of its spectral properties, namely formation of an excited dimer (excimer) and polarity-dependent changes in its fluorescence fine structure (P-value), we monitored the apoA-I self-association in its lipid-free form as a function of its concentration. Interactions in helices H5 (K133C) and H10 (F225C and K226C) were highlighted by excimer emission; while polarity changes were reported in helix H4 (K107C), as well as in helices H5 and H10. Mathematical models were developed to enrich data analysis and estimate association constants (KA) and oligomeric species distribution. Furthermore, we briefly discuss the usefulness of the multi-parametric fluorescent probe to monitor different equilibria, even at a single labelling position. Results suggest that apoA-I self-association must be considered to fully understand its physiological roles. Particularly, some contacts that stabilize discoidal HDL particles seem to be already present in the lipid-free apoA-I oligomers.


Assuntos
Apolipoproteína A-I/química , Corantes Fluorescentes/química , Sondas Moleculares/química , Multimerização Proteica , Pirenos/química , Apolipoproteína A-I/genética , Cisteína/química , Humanos , Mutação , Espectrometria de Fluorescência
9.
Food Chem ; 339: 127898, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32871303

RESUMO

In this study, lipid oxidation evaluation methods were compared for a krill-oil-in-water emulsion system. With this aim, thiocyanate and DPPP (diphenyl-1-pyrenylphosphine) fluorescence methods were comparatively examined to determine primary oxidation products. 2-thiobarbituric acid reactive substances (TBARS), hexanal and propanal formation were also monitored as secondary oxidations products. All oxidation experiments were performed via both auto-oxidation at 45 °C and light-riboflavin induced photooxidation at 37 °C. The results have shown that thiocyanate method was not suitable to measure lipid hydroperoxides by the both in auto- and photo-oxidation systems. On the other hand, fluorescence intensity of samples containing the DPPP probe increased during incubation period which indicates the formation of lipid hydroperoxides could be detected via this method. TBARS, hexanal and propanal concentrations also increased during storage period and the formation kinetics of secondary oxidation products was confirmed that the DPPP fluorescence method was accurate and reliable at different environmental conditions.


Assuntos
Emulsões/química , Euphausiacea/química , Óleos/química , Água/química , Animais , Antioxidantes/química , Euphausiacea/metabolismo , Compostos Organofosforados/química , Oxirredução , Tamanho da Partícula , Pirenos/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
10.
Biochim Biophys Acta Biomembr ; 1863(1): 183470, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32898535

RESUMO

The push-pull solvatochromic pyrene derivatives PA and PK have been applied to the study of model membrane vesicles, cells and purified human serum lipoproteins, using both confocal fluorescence microscopy and fluorescence spectroscopy. These polarity-sensitive probes provide information similar to that obtained by Laurdan or Prodan, i.e. mainly lipid order in biomembranes, but they have the essential advantage of being excitable by a standard 405 nm laser light, bypassing the use of multiphoton excitation. In addition, they are brighter and much more photostable than those dimethylamino naphthalene derivatives. Our results with model membrane spectroscopy (multilamellar vesicles) and with microscopy (giant unilamellar vesicles) showed the capacity of PA and PK to report differently on liquid-disordered, liquid-ordered and gel phase bilayers. Moreover, a ratiometric parameter, the Red/Blue Intensity Ratio (RBIR) could be used for inter-domain, inter-vesicle and even inter-technique comparison, and the appropriate microscopy-spectroscopy conversion coefficients could be estimated. In studies at the cellular level, PA probe stained almost exclusively the plasma membrane of red blood cells, revealing its high degree of lipid order. Using Chinese Hamster Ovary cells PA was shown to be an excellent probe for the detection of cytoplasmic lipid droplets, superior to Nile Red in that PA provides simultaneously a detailed information of membrane order in the whole cell, in which the lipid droplets appear with a very good contrast. Moreover, spectrofluorometric data of PA-stained serum lipoproteins indicated an essentially identical value of RBIR for lipid droplets and for high-density lipoproteins.


Assuntos
Membrana Eritrocítica , Corantes Fluorescentes , Gotículas Lipídicas , Lipoproteínas , Pirenos , Coloração e Rotulagem , Animais , Células CHO , Cricetulus , Membrana Eritrocítica/química , Membrana Eritrocítica/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Humanos , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Lipoproteínas/química , Lipoproteínas/farmacologia , Microscopia de Fluorescência , Pirenos/química , Pirenos/farmacologia
11.
Chemosphere ; 259: 127487, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650165

RESUMO

Polycyclic Aromatic Hydrocarbons (PAHs) have elicited increasing concern due to their ubiquitous occurrence in coastal marine environments and resultant toxicity in organisms. Due to their lipophilic nature, PAHs tend to accumulate in phytoplankton cells and thus subsequently transfer to other compartments of the marine ecosystem. The intrinsic fluorescence properties of PAHs in the ultraviolet (UV)/blue spectral range have recently been exploited to investigate their uptake modes, localization, and aggregation in various biological tissues. Here, we quantitatively evaluate the sorption of two model PAHs (phenanthrene and pyrene) in three marine phytoplankton species (Chaetoceros tenuissimus, Thalassiosira sp. and Proteomonas sp.) using a combined approach of UV excitation flow cytometry and fluorescence microscopy. Over a 48-h exposure to a gradient of PAHs, Thalassiosira sp. showed the highest proportion of PAH-sorbed cells (29% and 97% of total abundance for phenanthrene and pyrene, respectively), which may be attributed to its relatively high total lipid content (33.87 percent dry weight). Moreover, cell-specific pulse amplitude modulation (PAM) microscope fluorometry revealed that PAH sorption significantly reduced the photosynthetic quantum efficiency (Fv/Fm) of individual phytoplankton cells. We describe a rapid and precise hybrid method for the detection of sorption of PAHs on phytoplankton cells. Our results emphasize the ecologically relevant sub-lethal effects of PAHs in phytoplankton at the cellular level, even at concentrations where no growth inhibition was apparent. This work is the first study to address the cell-specific impacts of fluorescent toxicants in a more relevant toxicant-sorbed subpopulation; these cell-specific impacts have to date been unidentified in traditional population-based phytoplankton toxicity assays.


Assuntos
Fitoplâncton/efeitos dos fármacos , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Análise de Célula Única/métodos , Absorção Fisico-Química , Ecossistema , Citometria de Fluxo/métodos , Microscopia de Fluorescência/métodos , Fenantrenos/química , Fenantrenos/farmacocinética , Fitoplâncton/citologia , Fitoplâncton/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/farmacocinética , Pirenos/química , Pirenos/farmacocinética , Raios Ultravioleta
12.
J Phys Chem Lett ; 11(7): 2682-2688, 2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-32182072

RESUMO

Two photoswitchable compounds that can operate under visible light irradiation are prepared and investigated using spectroscopic and computational studies. These all-visible systems are based on the dimethyldihydropyrene (DHP)/cyclophanediene (CPD) photochromic couple connected either to a bipyridine (bpy) unit or to a (tris(bpy)ruthenium(II)) complex through a pyridinium bridge. In these compounds, the DHP to CPD isomerization and the reverse CPD to DHP conversion can be triggered by illumination with red (>630 nm) and blue (460 nm) lights, respectively. The unambiguous and reversible response of these systems triggered by visible light make them potential candidates for biological purposes and electronic devices.


Assuntos
Complexos de Coordenação/química , Pirenos/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/efeitos da radiação , Teoria da Densidade Funcional , Isomerismo , Ligantes , Luz , Modelos Químicos , Pirenos/síntese química , Pirenos/efeitos da radiação , Rutênio/química
13.
J Phys Chem Lett ; 11(7): 2701-2707, 2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-32191834

RESUMO

Light-matter interactions have always been a fundamentally significant topic that has attracted much attention. It is important to reveal a fluorophore-plasmon interaction on the nanoscale. However, as a powerful investigative tool, fluorescence spectroscopy still suffers from a limited spectral resolution and the susceptibility to interfering substances. In this work, excitation-emission synchronization-mediated surface-plasmon-coupled emission (EES-SPCE) is proposed to break the bottleneck. By actively screening the energy transitions for observation, an improved spectral resolution has been achieved, which is advantageous to the investigation of the fluorophore-plasmon interactions under different coupling modes. The spectral information related to the plasmonic interactions through tuning vibrational energy levels is clearly distinguished at directional emission angles. EES-SPCE is demonstrated to selectively and efficiently extract the coupled emission from the vibrational resolution, which would open up the opportunity to improve the capability of spectral feature identification and signal collection for practical applications of plasmonic fluorescence spectroscopy.


Assuntos
Antracenos/análise , Pirenos/análise , Antracenos/química , Fluorescência , Estudo de Prova de Conceito , Pirenos/química , Espectrometria de Fluorescência , Ressonância de Plasmônio de Superfície , Vibração
14.
Biosens Bioelectron ; 154: 112077, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32093895

RESUMO

The work presented herein demonstrates a hybrid bi-catalytic architecture for the complete electrochemical oxidation of ethanol. The new catalytic system contains pyrene-TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidinyl-N-oxyl) immobilized on the surface of carboxylated multi-walled carbon nanotubes (MWCNT-COOH), and oxalate decarboxylase enzyme (OxDc) immobilized onto a carbon cloth electrode. Electrolysis revealed a stable amperometric curve and an excellent current density value over a duration of 10 h. In addition, the hybrid system immobilized on the carbon electrode exhibits outstanding stability after electrolysis. Nuclear magnetic resonance (NMR) and gas chromatography (GC) demonstrate that the hybrid electrode system is able to oxidize ethanol to CO2 after 10 h of electrolysis. Overall, this study illustrates the enhancement of an enzymatic biofuel cell through the hybrid multi-catalytic systems, which exhibit high oxidation rates for all substrates involved in complete ethanol oxidation, enabling the collection of up to 12 electrons per molecule of ethanol.


Assuntos
Técnicas Biossensoriais , Dióxido de Carbono/química , Etanol/química , Nanotubos de Carbono/química , Carboxiliases/química , Catálise , Óxidos N-Cíclicos/química , Eletrólise , Enzimas Imobilizadas/química , Pirenos/química
15.
Nucleic Acids Res ; 48(7): 3975-3986, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32095808

RESUMO

Guanine-rich regions of the human genome can adopt non-canonical secondary structures. Their role in regulating gene expression has turned them into promising targets for therapeutic intervention. Ligands based on polyaromatic moieties are especially suitable for targeting G-quadruplexes utilizing their size complementarity to interact with the large exposed surface area of four guanine bases. A predictable way of (de)stabilizing specific G-quadruplex structures through efficient base stacking of polyaromatic functional groups could become a valuable tool in our therapeutic arsenal. We have investigated the effect of pyrene-modified uridine nucleotides incorporated at several positions of the thrombin binding aptamer (TBA) as a model system. Characterization using spectroscopic and biophysical methods provided important insights into modes of interaction between pyrene groups and the G-quadruplex core as well as (de)stabilization by enthalpic and entropic contributions. NMR data demonstrated that incorporation of pyrene group into G-rich oligonucleotide such as TBA may result in significant changes in 3D structure such as formation of novel dimeric topology. Site specific structural changes induced by stacking of the pyrene moiety on nearby nucleobases corelate with distinct thrombin binding affinities and increased resistance against nuclease degradation.


Assuntos
Aptâmeros de Nucleotídeos/química , Quadruplex G , Pirenos/química , Aptâmeros de Nucleotídeos/sangue , Aptâmeros de Nucleotídeos/metabolismo , Desoxirribonucleases , Dimerização , Entropia , Humanos , Termodinâmica , Trombina/metabolismo , Nucleotídeos de Uracila/química
16.
Molecules ; 25(3)2020 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-32050404

RESUMO

Density, viscosity and surface tension of Kolliphor® ELP, the nonionic surfactant aqueous solutions were measured at temperature T = 293-318 K and at 5K interval. Steady-state fluorescence measurements have been also made using pyrene as a probe. On the basis of the obtained results, a number of thermodynamic, thermo-acoustic and anharmonic parameters of the studied surfactant have been evaluated and interpreted in terms of structural effects and solute-solvent interactions. The results suggest that the molecules of studied surfactant at concentrations higher than the critical micelle concentration act as structure makers of the water structure.


Assuntos
Excipientes/química , Glicerol/química , Ácidos Oleicos/química , Polietilenoglicóis/química , Tensoativos/química , Água/química , Química Farmacêutica/métodos , Corantes Fluorescentes/química , Humanos , Pirenos/química , Soluções , Tensão Superficial , Temperatura , Termodinâmica
17.
Environ Pollut ; 260: 113984, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32041019

RESUMO

1-nitropyrene (1-NP) is a key component of diesel exhaust-sourced fine particulate matter (PM2.5). Our recent study demonstrated that gestational 1-NP exposure caused placental proliferation inhibition and fetal intrauterine growth restriction (IUGR). This study aimed to investigate the role of genotoxic stress on 1-NP-induced placental proliferation inhibition and fetal IUGR. Human trophoblasts were exposed to 1-NP (10 µM). Growth index was reduced and PCNA was downregulated in 1-NP-exposed placental trophoblasts. More than 90% of 1-NP-exposed trophoblasts were arrested in either G0/G1 or G2/M phases. CDK1 and cyclin B, two G2/M cycle-related proteins, and CDK2, a G0/G1 cycle-related protein, were reduced in 1-NP-exposed trophoblasts. Phosphorylated Rb, a downstream molecule of CDK2, was inhibited in 1-NP-exposed trophoblasts. Moreover, DNA double-strand break was observed and γ-H2AX, another indicator of DNA double-strand break, was upregulated in 1-NP-exposed trophoblasts. Phosphorylated ATM, a key molecule of genotoxic stress, and its downstream molecule Chk2 were elevated. By contrast, Cdc25A, a downstream target of Chk2, was reduced in 1-NP-exposed trophoblasts. Phenyl-N-t-butylnitrone (PBN), a free radical scavenger, inhibited 1-NP-induced genotoxic stress and trophoblast cycle arrest. Animal experiment showed that N-acetylcysteine (NAC), an antioxidant, rescued 1-NP-induced placental proliferation inhibition and fetal IUGR in mice. These results provide evidence that reactive oxygen species (ROS)-mediated cellular genotoxic stress partially contributes to 1-NP-induced placental proliferation inhibition and fetal IUGR.


Assuntos
Retardo do Crescimento Fetal , Mutagênicos/toxicidade , Pirenos/toxicidade , Trofoblastos , Animais , Ciclo Celular/efeitos dos fármacos , Dano ao DNA , Feminino , Humanos , Camundongos , Placenta , Gravidez , Pirenos/química , Espécies Reativas de Oxigênio/metabolismo
18.
Chemistry ; 26(22): 5075-5084, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32064675

RESUMO

Controlling the conformation and function of biomolecules through photoregulators holds great promise as a spatiotemporally controllable tool for disease control. In addition, introducing photoregulators into biomolecules has also found applications in constructing smart nanomaterials. In spite of the astonishing advances that have been made in the past few years, realizing highly controllable and efficient regulation over the conformation and function of biomolecules under physiological conditions is still challenging. Herein, sulfonated pyrene SPy was synthesized and used as a photoregulator to control the looping of single-stranded DNAs (ssDNAs) in aqueous solution. Due to its water solubility, SPy merits use in the study of biomolecules in aqueous solution. The looping of the doubly SPy-modified ssDNAs is stimulated by irradiation and regulated by SPy. Photoionization generates the radical cation of SPy (SPy.+ ). The association of SPy.+ with its neutral counterpart, SPy, gives rise to the dimer radical cation of SPy (SPy2 .+ ). During the association process, the stabilization energy released to form SPy2 .+ provides a driving force for the looping of ssDNAs. Conversely, the formed loop conformations were trapped by the formation of SPy2 .+ , and this allowed the looping dynamics to be investigated. The results reported herein suggest potential of SPy as a photoregulator for controlling the conformation and function of biomolecules under physiological conditions.


Assuntos
DNA/metabolismo , Pirenos/química , Compostos de Sulfidrila/química , Cátions , DNA/química , DNA de Cadeia Simples , Compostos de Sulfidrila/metabolismo
19.
Chem Commun (Camb) ; 56(10): 1501-1504, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31915759

RESUMO

A new DNA nanoprobe based on a Y-shape and pyrene-modified DNA self-assembly is developed to sensitively and specifically detect microRNA through a pyrene excimer-monomer switch. Exhibiting the capability of self-delivery and resistance to nuclease degradation, the nanoprobe has been successfully applied for microRNA imaging in live cells.


Assuntos
Sondas de DNA/química , MicroRNAs/metabolismo , Nanoestruturas/química , Linhagem Celular Tumoral , Sondas de DNA/metabolismo , Corantes Fluorescentes/química , Humanos , MicroRNAs/química , Microscopia Confocal , Pirenos/química
20.
Chemosphere ; 247: 125937, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31978665

RESUMO

This work reported the role of pyrene in formation of naturally occurring silver nanoparticles (AgNPs) via the reduction of silver ions by humic acid under the UV irradiation in the aquatic environment. An increase in temperature (25-90 °C), pH (5-9) or concentration of humic acid (2.5-15 mg/L) led to an enhanced formation of AgNPs. The TEM images indicated the formed AgNPs were spherical with an average particle size of ∼20 nm. Pyrene showed a limited capacity for the photoreduction of silver ions, and when both pyrene and humic acid were present, pyrene would compete with humic acid for the reduction of silver ions. However, the presence of pyrene would enhance the stability and suppress the antibacterial activity of natural AgNPs. The UV-vis spectra of AgNPs suspensions generated with pyrene did not change within 45 days. The inhibition rates against Escherichia coli of AgNPs generated with pyrene were 8-32% lower than those of AgNPs generated without pyrene. This study provides environmental implications on the fate and ecotoxicity of natural AgNPs with interaction of polycyclic aromatic hydrocarbons.


Assuntos
Nanopartículas Metálicas/química , Pirenos/química , Prata/química , Antibacterianos/química , Escherichia coli/efeitos dos fármacos , Substâncias Húmicas/análise , Íons , Tamanho da Partícula , Pirenos/toxicidade , Temperatura , Raios Ultravioleta
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