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1.
Int J Mol Sci ; 22(6)2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802920

RESUMO

Small molecule receptor-binding is dominated by weak, non-covalent interactions such as van-der-Waals hydrogen bonding or electrostatics. Calculating these non-covalent ligand-receptor interactions is a challenge to computational means in terms of accuracy and efficacy since the ligand may bind in a number of thermally accessible conformations. The conformational rotamer ensemble sampling tool (CREST) uses an iterative scheme to efficiently sample the conformational space and calculates energies using the semi-empirical 'Geometry, Frequency, Noncovalent, eXtended Tight Binding' (GFN2-xTB) method. This combined approach is applied to blind predictions of the modes and free energies of binding for a set of 10 drug molecule ligands to the cucurbit[n]urils CB[8] receptor from the recent 'Statistical Assessment of the Modeling of Proteins and Ligands' (SAMPL) challenge including morphine, hydromorphine, cocaine, fentanyl, and ketamine. For each system, the conformational space was sufficiently sampled for the free ligand and the ligand-receptor complexes using the quantum chemical Hamiltonian. A multitude of structures makes up the final conformer-rotamer ensemble, for which then free energies of binding are calculated. For those large and complex molecules, the results are in good agreement with experimental values with a mean error of 3 kcal/mol. The GFN2-xTB energies of binding are validated by advanced density functional theory calculations and found to be in good agreement. The efficacy of the automated QM sampling workflow allows the extension towards other complex molecular interaction scenarios.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Conformação Molecular , Teoria Quântica , Ligantes , Preparações Farmacêuticas/química , Prótons , Termodinâmica
2.
ACS Appl Mater Interfaces ; 13(2): 2269-2276, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33411497

RESUMO

Porphyrins are widely applied for imaging, diagnosis, and treatment of diseases because of their excellent photophysical properties. However, porphyrins easily tend to aggregate driven by hydrophobic interaction and π-π stacking in an aqueous medium, which causes fluorescence quenching of the porphyrins as well as limitation of cell uptake and intracellular accumulation. Herein, cucurbit[10]uril (CB[10]) was used to fully encapsulate cationic porphyrin (CPor) in the large cavity with strong binding affinity in aqueous solutions, and the CPor aggregates were efficient disassembled, companying remarkable enhancing its fluorescence intensity. The CB[10]-based host-guest complex provided excellent protection to CPor, resulting in less susceptibility to oxidation and imparting higher photostability to CPor for cell imaging. In addition, by complexation with CB[10], it was found that the fluorescence signals and photostability of CPor were also effectively improved in cells with different reactive oxygen species levels. It is highly anticipated that the large macrocyclic host cavity-triggered large-guest encapsulation strategy in this work will provide a convenient and efficient method for designing supramolecular porphyrin dyes, thus broadening the diagnosis and imaging application in cells and microorganisms.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Corantes Fluorescentes/química , Imidazóis/química , Imagem Óptica/métodos , Porfirinas/química , Células HCT116 , Células Hep G2 , Humanos , Microscopia Confocal/métodos , Fotólise , Espectrometria de Fluorescência/métodos
3.
Phys Chem Chem Phys ; 23(3): 2186-2192, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33438686

RESUMO

Subtle changes in molecular structure often lead to significant differences in host-guest interactions, which result in different host-guest recognition capabilities and dynamics behaviours in complex formation. Herein, we reveal the influence of the guest substituents on host-guest molecular recognition by molecular dynamics (MD) simulation and density functional theory (DFT) approaches. The results suggest that the binding energy barrier of acyclic cucurbit[4]uril (ACB[4]) with opiate metabolites gradually decreases. The methyl group in morphine (MOR) and morphine-3-glucuronide (M3G) strengthens the hydrophobicity of the guest, while depressing the energy loss of the desolvation of polar groups (e.g. hydroxyl) inside the ACB[4] cavity. However, in M3G, the 3-glucuronide group located outside the ACB[4] host cavity effectively alleviates the unfavourable desolvation effect of the hydroxyl and increases the binding constant by two orders of magnitude (compared with normorphine (NMOR)). Our findings stressed the essentiality of the binding mode and intermolecular noncovalent interactions in the host-guest selective binding ability.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Derivados da Morfina/química , Morfina/química , Teoria da Densidade Funcional , Ligação de Hidrogênio , Modelos Químicos , Simulação de Dinâmica Molecular
4.
J Agric Food Chem ; 69(1): 584-591, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33377764

RESUMO

According to a simple guest-replacement fluorescence turn-on mechanism, we constructed a fluorescent probe system based on cucurbit[10]uril (Q[10]) and protonated acridine (AD) to detect the pesticide dodine (DD). Formation of a homoternary inclusion complex AD2@Q[10] in both aqueous solution and solid state was studied by means of 1H NMR spectroscopy and X-ray crystallography. Although AD can emit strong fluorescence in aqueous solution, the homoternary inclusion complex AD2@Q[10] does not exhibit any fluorescence. Upon the addition of the pesticide DD into the aqueous solution of AD2@Q[10], the AD molecules in the Q[10] cavity are displaced by the pesticide DD, and strong fluorescence recovers. The fluorescent probe system based on Q[10] and AD provided a wide determination of DD from 0 to 4.0 × 10-5 mol·L-1 with a low limit of detection of 1.827 × 10-6 mol·L-1. The guest-replacement fluorescence turn-on mechanism is also confirmed by 1H NMR spectroscopy. Further, the fluorescent probe can directly detect DD residues in real agricultural products, and obvious fluorescence signal was observed under UV irradiation.


Assuntos
Acridinas/química , Hidrocarbonetos Aromáticos com Pontes/química , Guanidinas/análise , Imidazóis/química , Praguicidas/análise , Cristalografia por Raios X , Fluorescência , Corantes Fluorescentes/química , Espectroscopia de Ressonância Magnética
5.
J Am Chem Soc ; 142(40): 17024-17038, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-32926779

RESUMO

Broad-spectrum antivirals are powerful weapons against dangerous viruses where no specific therapy exists, as in the case of the ongoing SARS-CoV-2 pandemic. We discovered that a lysine- and arginine-specific supramolecular ligand (CLR01) destroys enveloped viruses, including HIV, Ebola, and Zika virus, and remodels amyloid fibrils in semen that promote viral infection. Yet, it is unknown how CLR01 exerts these two distinct therapeutic activities. Here, we delineate a novel mechanism of antiviral activity by studying the activity of tweezer variants: the "phosphate tweezer" CLR01, a "carboxylate tweezer" CLR05, and a "phosphate clip" PC. Lysine complexation inside the tweezer cavity is needed to antagonize amyloidogenesis and is only achieved by CLR01. Importantly, CLR01 and CLR05 but not PC form closed inclusion complexes with lipid head groups of viral membranes, thereby altering lipid orientation and increasing surface tension. This process disrupts viral envelopes and diminishes infectivity but leaves cellular membranes intact. Consequently, CLR01 and CLR05 display broad antiviral activity against all enveloped viruses tested, including herpesviruses, Measles virus, influenza, and SARS-CoV-2. Based on our mechanistic insights, we potentiated the antiviral, membrane-disrupting activity of CLR01 by introducing aliphatic ester arms into each phosphate group to act as lipid anchors that promote membrane targeting. The most potent ester modifications harbored unbranched C4 units, which engendered tweezers that were approximately one order of magnitude more effective than CLR01 and nontoxic. Thus, we establish the mechanistic basis of viral envelope disruption by specific tweezers and establish a new class of potential broad-spectrum antivirals with enhanced activity.


Assuntos
Antivirais/química , Antivirais/farmacologia , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Organofosfatos/farmacologia , Proteínas do Envelope Viral/efeitos dos fármacos , Fosfatase Ácida/química , Fosfatase Ácida/metabolismo , Amiloide/antagonistas & inibidores , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Arginina/química , Betacoronavirus/efeitos dos fármacos , Hidrocarbonetos Aromáticos com Pontes/química , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/virologia , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Humanos , Lipídeos/química , Lisina/química , Espectroscopia de Ressonância Magnética , Organofosfatos/química , Proteínas Secretadas pela Vesícula Seminal/química , Proteínas Secretadas pela Vesícula Seminal/metabolismo , Relação Estrutura-Atividade , Proteínas do Envelope Viral/metabolismo , Zika virus/efeitos dos fármacos
6.
J Chromatogr A ; 1626: 461361, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797840

RESUMO

The alkaloid enantiomers are well-known to have different physiological and pharmacological effects, and to play an important role in enantioselectivity metabolism with enzymes catalysis in tobacco plants. Here, we developed an improved method for simultaneous and high-precision determination of the individual enantiomers of nornicotine, anatabine and anabasine in four tobacco matrices, based on an achiral gas chromatography-nitrogen phosphorus detector (GCNPD) with commonly available Rtx-200 column using (1S)-(-)-camphanic chloride derivatization. The method development consists of the optimization of extraction and derivatization, screening of achiral column, analysis of the fragmentation mechanisms and evaluation of matrix effect (ME). Under the optimized experimental conditions, the current method exhibited excellent detection capability for the alkaloid enantiomers, with coefficients of determination (R2) > 0.9989 and normality test of residuals P > 0.05 in linear regression parameters. The ME can be neglected for the camphanic derivatives. The limit of detection (LOD) and limit of quantitation (LOQ) ranged from 0.087 to 0.24 µg g - 1 and 0.29 to 0.81 µg g - 1, respectively. The recoveries and within-laboratory relative standard deviations (RSDR) were 94.3%~104.2% and 0.51%~3.89%, respectively. The developed method was successfully applied to determine the enantiomeric profiling of cultivars and curing processes. Tobacco cultivars had a significant impact on the nornicotine, anatabine, anabasine concentration and enantiomeric fraction (EF) of (R)-nornicotine, whereas the only significant change induced by the curing processes was an increase in the EF of (R)-anabasine.


Assuntos
Alcaloides/análise , Anabasina/análise , Cromatografia Gasosa/métodos , Nicotina/análogos & derivados , Piridinas/análise , Tabaco/química , Alcaloides/química , Anabasina/química , Hidrocarbonetos Aromáticos com Pontes/química , Cloretos/química , Lactonas/química , Nicotina/análise , Nicotina/química , Piridinas/química , Estereoisomerismo
7.
Nat Biomed Eng ; 4(5): 507-517, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32393892

RESUMO

Treatment of patients with diabetes with insulin and pramlintide (an amylin analogue) is more effective than treatment with insulin only. However, because mixtures of insulin and pramlintide are unstable and have to be injected separately, amylin analogues are only used by 1.5% of people with diabetes needing rapid-acting insulin. Here, we show that the supramolecular modification of insulin and pramlintide with cucurbit[7]uril-conjugated polyethylene glycol improves the pharmacokinetics of the dual-hormone therapy and enhances postprandial glucagon suppression in diabetic pigs. The co-formulation is stable for over 100 h at 37 °C under continuous agitation, whereas commercial formulations of insulin analogues aggregate after 10 h under similar conditions. In diabetic rats, the administration of the stabilized co-formulation increased the area-of-overlap ratio of the pharmacokinetic curves of pramlintide and insulin from 0.4 ± 0.2 to 0.7 ± 0.1 (mean ± s.d.) for the separate administration of the hormones. The co-administration of supramolecularly stabilized insulin and pramlintide better mimics the endogenous kinetics of co-secreted insulin and amylin, and holds promise as a dual-hormone replacement therapy.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Composição de Medicamentos , Glucagon/metabolismo , Insulina/uso terapêutico , Polipeptídeo Amiloide das Ilhotas Pancreáticas/uso terapêutico , Animais , Hidrocarbonetos Aromáticos com Pontes/química , Difusão , Vias de Administração de Medicamentos , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Imidazóis/química , Insulina/administração & dosagem , Insulina/farmacocinética , Insulina/farmacologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/administração & dosagem , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacocinética , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacologia , Masculino , Polietilenoglicóis/química , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Suínos
8.
Chemistry ; 26(43): 9445-9448, 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32343009

RESUMO

Current drug delivery systems gain more functions with increased complexity. With the idea of less is more, we synthesized hexanoate-cucurbit[7]uril (CB[7]C5 COONa) with multiple promising features for drug delivery. The hexanoate group integrates multiple functions. It endows CB[7]C5 COONa extremely high solubility of over 600 mg mL-1 and well-defined pH-controlled release ability without sacrificing on the high binding affinity of CB[7] cavity. Based on the pH-controlled release ability, CB[7]C5 COONa can be used for controlling the bioactivity of drug molecules. We anticipate that the strategy of function integration would be useful for the design of simple yet powerful drug delivery systems.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Caproatos/química , Imidazóis/química , Preparações de Ação Retardada , Sistemas de Liberação de Medicamentos/métodos , Solubilidade
9.
Org Biomol Chem ; 18(16): 3125-3134, 2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-32255146

RESUMO

Two organoselenium compounds, both of which were modified with two primary amine groups, were designed and synthesized to mimic the catalytic properties of glutathione peroxidase (GPx). It was demonstrated that the catalytic mechanism of the diselenide organoselenium compound (compound 1) was a ping-pong mechanism while that of the selenide organoselenium compound (compound 2) was a sequential mechanism. The pH-controlled switching of the catalytic activities was achieved by controlling the formation and dissociation of the pseudorotaxanes based on the organoselenium compounds and cucurbit[6]uril (CB[6]). Moreover, the switching was reversible at pH between 7 and 9 for compound 1 or between 7 and 10 for compound 2.


Assuntos
Glutationa Peroxidase/metabolismo , Concentração de Íons de Hidrogênio , Mimetismo Molecular , Rotaxanos/metabolismo , Aminas/química , Hidrocarbonetos Aromáticos com Pontes/química , Catálise , Imidazóis/química , Compostos Organosselênicos/química
10.
Chimia (Aarau) ; 74(1): 9-17, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32200781

RESUMO

The degenerative xanthate addition transfer to alkenes allows the synthesis of a broad range of protected, and in some cases enantiopure, α, ß, and γ-amino acids, including proline and pipecolic derivatives, as well as fluorinated congeners and ß-lactams. The radical addition furnishes naturally latent mercapto-α-amino acids that are ideally equipped for native chemical ligation. Most of the amino acid structures accessible rapidly by this chemistry would otherwise require tedious multi-step syntheses.


Assuntos
Aminoácidos/química , Hidrocarbonetos Aromáticos com Pontes/química , Tionas/química , Estereoisomerismo
11.
Anal Chim Acta ; 1104: 164-171, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32106948

RESUMO

This paper demonstrated a simple and validated fluorescence enhancing method to selectively recognize and discriminate the amino acid phenylalanine (Phe). 1H NMR spectroscopy reveal that the palmatine (PAL) can be encapsulated into the cucurbit [8]uril (Q [8]) in aqueous solution to form stable 1:2 host-guest inclusion complex PAL2@Q [8], which exhibits moderate intensity fluorescence property. Interestingly, the addition of the Phe into the inclusion complex PAL2@Q [8] leads to dramatically enhancing of the fluorescence intensity. In contrast, the addition of any other natural amino acids into the inclusion complex PAL2@Q [8] gives no fluorescence variation. Furthermore, it is easy to detect the concentration of Phe in target aqueous solution according to the linear relationship between fluorescence intensity and concentration of the Phe.


Assuntos
Alcaloides de Berberina/química , Técnicas Biossensoriais/métodos , Hidrocarbonetos Aromáticos com Pontes/química , Corantes Fluorescentes/química , Imidazóis/química , Fenilalanina/análise , Calorimetria , Soluções , Espectrometria de Fluorescência , Água/química
12.
Eur J Med Chem ; 191: 112162, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32101781

RESUMO

Phospholipases are enzymes that are involved in the hydrolysis of acyl and phosphate esters of phospholipids, generating secondary messengers that have implications in various cellular processes including proliferation, differentiation and motility. As such inhibitors of phospholipases have been widely studied for their use as anti-cancer therapeutics. Phosphatidylcholine-specific phospholipase C (PC-PLC) is implicated in the progression of a number of cancer cell lines including aggressing triple-negative breast cancers. Most current studies on PC-PLC have utilised D609 as the standard inhibitor however it is known to have multiple failings, including poor stability in aqueous media. 2-Morpholinobenzoic acids were recently identified using vHTS as a potential class of lead compounds, with improvements over D609. In this work 129 analogues in this class were prepared and their PC-PLC inhibitory activity was assessed. It was found that the majority of these novel compounds had improved activity when compared to D609 with the most potent inhibitors completely inhibiting enzyme activity. It was determined that the best compound/s contained a morpholino and 2-substituted N-benzyl moieties with these findings explained using molecular modelling. The compounds reported here will allow for improved study of PC-PLC activity.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/farmacologia , Desenvolvimento de Medicamentos , Inibidores Enzimáticos/farmacologia , Tionas/farmacologia , Fosfolipases Tipo C/antagonistas & inibidores , Hidrocarbonetos Aromáticos com Pontes/síntese química , Hidrocarbonetos Aromáticos com Pontes/química , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Modelos Moleculares , Estrutura Molecular , Norbornanos , Relação Estrutura-Atividade , Tiocarbamatos , Tionas/síntese química , Tionas/química , Fosfolipases Tipo C/metabolismo
13.
Org Biomol Chem ; 18(4): 755-766, 2020 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-31912862

RESUMO

The design of small organic molecules with a predictable and desirable DNA-binding mechanism is a topical research task for biomedicine application. Herein, we demonstrate an attractive supramolecular strategy for controlling the non-covalent ligand-DNA interaction by binding with cucurbituril as a synthetic receptor. With a combination of UV/vis, CD and NMR experiments, we demonstrate that the bis-styryl dye with two suitable binding sites can involve double stranded DNA and cucurbituril in the formation of the supramolecular triad. The ternary assembly is formed as a result of the interaction of macrocyclic cucurbituril with one pyridinium fragment of the bis-styryl dye, while the second pyridinium fragment of the dye is effectively associated with DNA backbones, which leads to a change in the ligand-DNA binding mode from aggregation to a minor groove. This exciting outcome was supported by molecular docking studies that help to understand the molecular orientation of the supramolecular triad and elucidate the destruction of dye aggregates caused by cucurbituril. These studies provide valuable information on the mechanisms of DNA binding to small molecules and recognition processes in bioorganic supramolecular assemblies constructed from multiple non-covalent interactions.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Corantes/química , DNA/química , Imidazóis/química , Estirenos/química , Animais , Bovinos , Ligantes , Compostos Macrocíclicos/química , Simulação de Acoplamento Molecular
14.
Chem Commun (Camb) ; 56(15): 2296-2299, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31989125

RESUMO

We developed an epigenetically active, cooperative DNA binding transcription factor platform assisted by cucurbit[7]uril (CB7) host-guest modules. This new type of molecule termed ePIP-HoGu not only mimics the operation of transcription factors as a pair but also recruits the epigenetic modifier to a particular DNA locus.


Assuntos
DNA/química , Epigênese Genética/genética , Fatores de Transcrição/química , Hidrocarbonetos Aromáticos com Pontes/química , DNA/genética , Imidazóis/química , Estrutura Molecular , Fatores de Transcrição/síntese química , Fatores de Transcrição/genética
15.
Chem Commun (Camb) ; 56(11): 1629-1632, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31939471

RESUMO

This article presents a new label-free fluorescence assay based on supramolecular self-assembly of cucurbit[7]uril and specific peptide Gly-Pro-Phe-Gly for monitoring DPP4 activity in clinical samples. It also displays a good potential application in high-throughput screening of DPP4 inhibitors.


Assuntos
Dipeptidil Peptidase 4/sangue , Ensaios Enzimáticos/métodos , Laranja de Acridina/química , Animais , Hidrocarbonetos Aromáticos com Pontes/química , Dipeptidil Peptidase 4/química , Inibidores da Dipeptidil Peptidase IV/química , Feminino , Corantes Fluorescentes/química , Humanos , Imidazóis/química , Limite de Detecção , Masculino , Camundongos Endogâmicos C57BL , Oligopeptídeos/química , Espectrometria de Fluorescência/métodos
16.
Chem Commun (Camb) ; 56(10): 1549-1552, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31930244

RESUMO

In accordance with the rapid increase in demand for selective and spatial chemical tagging, and accurate detection of proteins of interest, we develop a sensitive protein detection method, termed "Supra-blot" capitalizing on high-affinity host-guest interaction between cucurbit[7]uril (CB[7]) and adamantylammonium (AdA). The method can directly detect chemically tagged proteins without false-positive signals caused by endogenous biomolecules. Not only a single specific protein, but also spatially localized proteins in cells were labeled with AdA, and selectively detected by a host molecule-enzyme hybrid, CB[7]-conjugated horseradish peroxidase (CB[7]-HRP) generating amplified chemiluminescence signals. This study shows the great potential of Supra-blot for accurate and reliable detection of proteins of interest in cells.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Peroxidase do Rábano Silvestre/química , Imidazóis/química , Medições Luminescentes/métodos , Amantadina/química , Compostos de Amônio/química , Células HEK293 , Histonas/química , Histonas/metabolismo , Peroxidase do Rábano Silvestre/metabolismo , Humanos
17.
Analyst ; 145(3): 1033-1040, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31834331

RESUMO

A novel fluorescent probe (OFN) based on nopinone for the detection of hypochlorite has been developed. The probe OFN exhibited a colorimetric and ratiometric response to hypochlorite with good selectivity, high sensitivity (the low detection limit is 0.136 µM) and fast response time (30 s). In response to ClO-, an obvious change was observed in both the fluorescence and absorption spectra, followed by the visible color change from colorless to yellow and the fluorescence color change from yellow to green. The sensing mechanism confirmed that the oxime group of OFN was oxidized to the aldehyde group, which was proved by HRMS and 1H NMR. What is more, the probe was used not only to detect the concentration of ClO- in water samples but also for monitoring ClO- in living cells.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Colorimetria/métodos , Corantes Fluorescentes/química , Ácido Hipocloroso/análise , Água/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Macrófagos/patologia , Camundongos , Microscopia Confocal , Teoria Quântica , Células RAW 264.7 , Espectrometria de Fluorescência
18.
Food Microbiol ; 86: 103335, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703853

RESUMO

The presence of eight common structural enterocin genes, singly or in varying combinations, in the genome of 15 antagonistic Enterococcus spp. previously isolated from artisan Greek Graviera and Galotyri retail cheeses was tested and associated with the mode of enterocin (Ent+) antilisterial activity of each isolate in three liquid culture media. The isolates were assigned to nine distinct strain genotypes of E. faecium (4 strains), E. durans (2) and E. faecalis (3). All strains were non-hemolytic, except for a cyl-positive E. faecalis genotype isolated from Galotyri cheese, which was strongly listericidal. All other strains varied from being listeriostatic to weakly listericidal in MRS and M17 broth, whereas all failed to inhibit listerial growth in skim milk. Two E. faecium strains retained strong Ent+ activity following neutralization and filter-sterilization of their MRS or M17 co-culture supernatants, whereas, all others required contact or proximity of their viable cells with L. monocytogenes cells in order to display activity. Additional studies to evaluate safety and potential synergistic effects of each strain genotype with starter LAB species in real milk environments will reveal the most active and truly harmless Enterococcus genotypes to be applied as co-starter or bioprotective adjunct cultures in traditional Greek cheese technologies.


Assuntos
Queijo/microbiologia , Enterococcus/química , Listeria monocytogenes/efeitos dos fármacos , Leite/microbiologia , Animais , Hidrocarbonetos Aromáticos com Pontes/química , Hidrocarbonetos Aromáticos com Pontes/metabolismo , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Bovinos , Meios de Cultura/química , Meios de Cultura/metabolismo , Enterococcus/genética , Enterococcus/isolamento & purificação , Enterococcus/metabolismo , Grécia , Listeria monocytogenes/crescimento & desenvolvimento
19.
Chem Commun (Camb) ; 56(3): 360-363, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31825399

RESUMO

A crystalline biohybrid with a 4 : 1 protein : cucurbituril mass ratio is presented. This result was achieved by engineering additional cucurbit[7]uril (Q7) binding sites into a ß-propeller protein. In contrast to the parent protein, Q7-controlled assembly of the engineered variant occurred in solution, as evidenced by NMR and SAXS measurements.


Assuntos
Proteínas de Bactérias/química , Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Sequência de Aminoácidos , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Hidrocarbonetos Aromáticos com Pontes/metabolismo , Imidazóis/metabolismo , Lectinas/química , Lectinas/genética , Lectinas/metabolismo , Ressonância Magnética Nuclear Biomolecular , Ralstonia solanacearum/metabolismo , Espalhamento a Baixo Ângulo , Difração de Raios X
20.
Chemistry ; 26(1): 198-205, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31643112

RESUMO

A 2D supramolecular organic framework (SOF) based on synthetic macrocycles has been constructed in water by a self-assembly strategy. Two new organic monomers of this SOF, possessing viologen and azobenzene functional groups, form a stimuli-responsive host-guest system upon cooperatively binding with cucurbit[8]uril rings. The reversible formation and dissociation of 2D SOF can be realized by the isomerization of azobenzene under ultraviolet and visible light. The light-responsive property of the SOF is highly reversible and stable for up to four cycles. Moreover, azoreductase produced by Escherichia coli can reduce the N=N double bond of azobenzene entities, resulting in fluorescence recovery of the system. As an excellent and effective fluorescent probe, the SOF can detect azoreductase activity for real-time monitoring of the growth process of Escherichia coli. The dual-stimuli responsive 2D SOF is envisioned to drive the development of responsive devices with complex functions.


Assuntos
Substâncias Macromoleculares/química , NADH NADPH Oxirredutases/metabolismo , Compostos Azo/química , Hidrocarbonetos Aromáticos com Pontes/química , Escherichia coli/metabolismo , Imidazóis/química , Isomerismo , Luz , Substâncias Macromoleculares/metabolismo , NADH NADPH Oxirredutases/química , NADH NADPH Oxirredutases/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Espectrometria de Fluorescência
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