Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 296
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Analyst ; 149(18): 4623-4632, 2024 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-39101528

RESUMEN

The "antenna effect" is one of the most important energy transfer modes in lanthanide light-emitting polymers. In this study, novel luminescent nanostructured coordination polymers (Eu-PCP) were synthesized in one step using Eu3+ as the central metal ion and 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) as the organic ligand. The unique "antenna effect" observed between Eu3+ and TCPP leads to a substantial improvement in the electrochemiluminescence (ECL) emission efficiency. Eu-PCP exhibits good cathodic ECL characteristics. Additionally, Au@SnS2 nanosheets exhibit favorable electrical conductivity, biocompatibility, and a significant specific surface area. This makes them a suitable choice as substrate materials for the modification of electrode surfaces and capturing antigens. Being well known, the development of sensitive and rapid methods to detect chloramphenicol is essential for food safety. Based on this, we report a novel competitive electrochemiluminescence immunoassay to achieve ultra-sensitive and highly specific detection of chloramphenicol. The linear range was 0.0002-500 ng mL-1 and the detection limit was 0.09 pg mL-1. Apart from that, the experimental results proved that it provided a new analytical tool for the detection of antibiotic residues in food safety.


Asunto(s)
Cloranfenicol , Técnicas Electroquímicas , Europio , Oro , Límite de Detección , Mediciones Luminiscentes , Polímeros , Porfirinas , Europio/química , Cloranfenicol/análisis , Cloranfenicol/química , Inmunoensayo/métodos , Porfirinas/química , Mediciones Luminiscentes/métodos , Técnicas Electroquímicas/métodos , Oro/química , Polímeros/química , Contaminación de Alimentos/análisis , Antibacterianos/análisis , Antibacterianos/química , Compuestos de Estaño/química , Animales , Complejos de Coordinación/química
2.
Environ Res ; 259: 119447, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-38908660

RESUMEN

The worldwide demand for antibiotics has experienced a notable surge, propelled by the repercussions of the COVID-19 pandemic and advancements in the global healthcare sector. A prominent challenge confronting humanity is the unregulated release of antibiotic-laden wastewater into the environment, posing significant threats to public health. The adoption of affordable carbon-based adsorbents emerges as a promising strategy for mitigating the contamination of antibiotic wastewater. Here, we report the synthesis of novel porous carbons (MPC) through a direct pyrolysis of MIL-53-NH2(Al) and tannic acid (TANA) under N2 atmosphere at 800 °C for 4 h. The effect of TANA amount ratios (0%-20%, wt wt-1) on porous carbon structure and adsorption performance was investigated. Results showed that TANA modification resulted in decreased surface area (1,600 m2 g-1-949 m2 g-1) and pore volume (2.3 cm3 g-1-1.7 cm3 g-1), but supplied hydroxyl functional groups. Adsorption kinetic, intraparticle diffusion, and isotherm were examined, indicating the best fit of Elovich and Langmuir models. 10%-TANA-MPC obtained an ultrahigh adsorption capacity of 564.4 mg g-1, which was approximately 2.1 times higher than that of unmodified porous carbon. 10%-TANA-MPC could be easily recycled up to 5 times, and after reuse, this adsorbent still remained highly stable in morphology and surface area. The contribution of H bonding, pore-filling, electrostatic and π-π interactions to chloramphenicol adsorption was clarified. It is recommended that TANA-modified MIL-53-NH2(Al)-derived porous carbons act as a potential adsorbent for removal of pollutants effectively.


Asunto(s)
Carbono , Cloranfenicol , Taninos , Contaminantes Químicos del Agua , Taninos/química , Adsorción , Cloranfenicol/química , Porosidad , Carbono/química , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/análisis , Antibacterianos/química , Estructuras Metalorgánicas/química , Polifenoles
3.
Mikrochim Acta ; 191(9): 552, 2024 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-39167265

RESUMEN

N-doped hollow carbon spheres (NHCSs) with different shell thicknesses are constructed using various amounts of SiO2 precursor. An interconnected framework with diminished wall thickness ensures an efficient and continuous electron transport which helps to enhance the performance of NHCS. Improvement of the electrocatalytic performance was shown in the determination of antibiotic drug chloramphenicol (CAP) due to the unique hollow thin shell morphology, ample defect sites, accessible surface area, higher surface-to-volume ratio and an synergistic effect. Boosted electrocatalytic activity of 1.5 N-doped HCS (1.5 NHCS) was applied to detect CAP with a linear range and detection limit of 1-1150 µM and 0.098 µM (n = 3), respectively, with superior storage stability and considerable sensitivity. These results suggest that the proposed work can be successfully applied to the determination of CAP in milk and water samples.


Asunto(s)
Antibacterianos , Carbono , Cloranfenicol , Técnicas Electroquímicas , Límite de Detección , Leche , Cloranfenicol/análisis , Cloranfenicol/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Carbono/química , Antibacterianos/análisis , Leche/química , Animales , Contaminantes Químicos del Agua/análisis , Electrodos , Nitrógeno/química , Dióxido de Silicio/química
4.
Drug Dev Ind Pharm ; 50(5): 446-459, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38622817

RESUMEN

OBJECTIVE: The aim of the present study was to develop and optimize a wound dressing film loaded with chloramphenicol (CAM) and ibuprofen (IBU) using a Quality by Design (QbD) approach. SIGNIFICANCE: The two drugs have been combined in the same dressing as they address two critical aspects of the wound healing process, namely prevention of bacterial infection and reduction of inflammation and pain related to injury. METHODS: Three critical formulation variables were identified, namely the ratios of Kollicoat SR 30D, polyethylene glycol 400 and polyvinyl alcohol. These variables were further considered as factors of an experimental design, and 17 formulations loaded with CAM and IBU were prepared via solvent casting. The films were characterized in terms of dimensions, mechanical properties and bioadhesion. Additionally, the optimal formulation was characterized regarding tensile properties, swelling behavior, water vapor transmission rate, surface morphology, thermal behavior, goniometry, in vitro drug release, cell viability, and antibacterial activity. RESULTS: The film was optimized by setting minimal values for the folding endurance, adhesive force and hardness. The optimally formulated film showed good fluid handling properties in terms of swelling behavior and water vapor transmission rate. IBU and CAM were released from the film up to 80.9% and 82.5% for 8 h. The film was nontoxic, and the antibacterial activity was prominent against Micrococcus spp. and Streptococcus pyogenes. CONCLUSIONS: The QbD approach was successfully implemented to develop and optimize a novel film dressing promising for the treatment of low-exuding acute wounds prone to infection and inflammation.


Asunto(s)
Antibacterianos , Vendajes , Cloranfenicol , Ibuprofeno , Cicatrización de Heridas , Ibuprofeno/administración & dosificación , Ibuprofeno/química , Ibuprofeno/farmacología , Cicatrización de Heridas/efectos de los fármacos , Cloranfenicol/administración & dosificación , Cloranfenicol/farmacología , Cloranfenicol/química , Antibacterianos/administración & dosificación , Antibacterianos/farmacología , Antibacterianos/química , Liberación de Fármacos , Humanos , Alcohol Polivinílico/química , Polietilenglicoles/química , Animales , Supervivencia Celular/efectos de los fármacos , Química Farmacéutica/métodos
5.
Proteins ; 89(9): 1193-1204, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33983672

RESUMEN

Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the first characterization of a multidrug transporter belonging to the major facilitator superfamily from the genus Salmonella. We show that several clinical Salmonella Typhi (S. Typhi) isolates constitutively express the styMdtM (STY4874) gene, which encodes a known multidrug-resistance (MDR) transporter. Guided by the structure of the Escherichia coli (E. coli) homolog, we studied two residues critical for substrate transport, Asp25 and Arg111. Mutation of Asp25 to glutamate did not affect the transport function of styMdtM, whereas mutation to alanine reduced its transport activity, suggesting that a negative charge at this position is critical for substrate translocation across the membrane. Substrate-affinity measurements by intrinsic fluorescence spectroscopy showed that the Asp25Ala mutant retained its capacity to bind substrate, albeit at a lower level. Mutation of Arg111 to alanine resulted in a decrease in secondary structure content of the transporter, and mutation to lysine completely destabilized the structure of the transporter. A homology model of styMdtM suggests that Arg111 is important for stabilizing the transmembrane domain by mediating necessary interactions between neighboring helices. Together, our studies provide new structural and mechanistic insights into the Salmonella MDR transporter styMdtM.


Asunto(s)
Antibacterianos/química , Proteínas Bacterianas/química , Cloranfenicol/química , Farmacorresistencia Bacteriana/genética , Proteínas de Transporte de Monosacáridos/química , Mutación , Sustitución de Aminoácidos , Antibacterianos/farmacología , Arginina/química , Arginina/metabolismo , Ácido Aspártico/química , Ácido Aspártico/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sitios de Unión , Transporte Biológico , Cloranfenicol/farmacología , Expresión Génica , Humanos , Cinética , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Proteínas de Transporte de Monosacáridos/genética , Proteínas de Transporte de Monosacáridos/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Salmonella typhi/efectos de los fármacos , Salmonella typhi/genética , Salmonella typhi/aislamiento & purificación , Salmonella typhi/metabolismo , Especificidad por Sustrato , Termodinámica , Fiebre Tifoidea/microbiología
6.
Biochem Biophys Res Commun ; 579: 105-109, 2021 11 19.
Artículo en Inglés | MEDLINE | ID: mdl-34597992

RESUMEN

The aptamer domain of the theophylline riboswitch was randomized to generate a library containing millions of different variants. Dual genetic selection utilizing the cat-upp fusion gene was performed for the library, which successfully led to the identification of a caffeine-specific synthetic riboswitch. When a chloramphenicol-resistance gene was expressed under control of this riboswitch, E. coli cells showed chloramphenicol resistance only in the presence of caffeine. When inserted upstream of the gfpuv or lacZ gene, the caffeine riboswitch induced the expression of green fluorescent protein or ß-galactosidase in the presence of caffeine, respectively. When tested with various concentrations of caffeine, the ß-galactosidase activity was proportional to the amount of caffeine, clearly indicating the caffeine-dependent gene regulation by the caffeine riboswitch.


Asunto(s)
Cafeína/química , Oligonucleótidos , Riboswitch , Selección Genética , Teofilina/química , Cloranfenicol/química , Resistencia a Medicamentos , Escherichia coli/metabolismo , Regulación de la Expresión Génica , Proteínas Fluorescentes Verdes/metabolismo , Pruebas de Sensibilidad Microbiana , Plásmidos/metabolismo , Proteínas Recombinantes de Fusión/química , beta-Galactosidasa/metabolismo
7.
Biochem Biophys Res Commun ; 562: 127-132, 2021 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-34051576

RESUMEN

A novel nitrogen mustard CBISC has been synthesized and evaluated as an anticancer agent. CBISC has been shown to exhibit enhanced cell proliferation inhibition properties against mutant p53 cell lines colorectal cancer WiDr, pancreatic cancer (MIAPaCa-2 and PANC-1), and triple negative breast cancer (MDA-MB-231 and MDA-MB-468). In vitro mechanism of action studies revealed perturbations in the p53 pathway and increased cell death as evidenced by western blotting, immunofluorescent microscopy and MTT assay. Further, in vivo studies revealed that CBISC is well tolerated in healthy mice and exhibited significant in vivo tumor growth inhibition properties in WiDr and MIAPaCa-2 xenograft models. These studies illustrate the potential utility of CBISC as an anticancer agent.


Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Daño del ADN , Proteínas Mutantes/metabolismo , Proteína p53 Supresora de Tumor/genética , Animales , Apoptosis/efectos de los fármacos , Sistemas CRISPR-Cas/genética , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Clorambucilo/química , Clorambucilo/farmacología , Cloranfenicol/química , Cloranfenicol/farmacología , Femenino , Ratones Desnudos , Poli(ADP-Ribosa) Polimerasas/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
8.
RNA ; 25(5): 600-606, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30733327

RESUMEN

The 70S ribosome is a major target for antibacterial drugs. Two of the classical antibiotics, chloramphenicol (CHL) and erythromycin (ERY), competitively bind to adjacent but separate sites on the bacterial ribosome: the catalytic peptidyl transferase center (PTC) and the nascent polypeptide exit tunnel (NPET), respectively. The previously reported competitive binding of CHL and ERY might be due either to a direct collision of the two drugs on the ribosome or due to a drug-induced allosteric effect. Because of the resolution limitations, the available structures of these antibiotics in complex with bacterial ribosomes do not allow us to discriminate between these two possible mechanisms. In this work, we have obtained two crystal structures of CHL and ERY in complex with the Thermus thermophilus 70S ribosome at a higher resolution (2.65 and 2.89 Å, respectively) allowing unambiguous placement of the drugs in the electron density maps. Our structures provide evidence of the direct collision of CHL and ERY on the ribosome, which rationalizes the observed competition between the two drugs.


Asunto(s)
Antibacterianos/química , Cloranfenicol/química , Eritromicina/química , Subunidades Ribosómicas/efectos de los fármacos , Thermus thermophilus/efectos de los fármacos , Antibacterianos/farmacología , Sitios de Unión , Unión Competitiva , Cloranfenicol/farmacología , Cristalografía por Rayos X , Eritromicina/farmacología , Escherichia coli/química , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Modelos Moleculares , Peptidil Transferasas/antagonistas & inhibidores , Peptidil Transferasas/química , Peptidil Transferasas/genética , Peptidil Transferasas/metabolismo , Unión Proteica , Biosíntesis de Proteínas , Conformación Proteica , Subunidades Ribosómicas/genética , Subunidades Ribosómicas/metabolismo , Subunidades Ribosómicas/ultraestructura , Thermus thermophilus/química , Thermus thermophilus/genética , Thermus thermophilus/metabolismo
9.
Mikrochim Acta ; 188(1): 22, 2021 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-33404928

RESUMEN

An electrochemical aptasensor, including the polyethyleneimine-graphite-like carbon nitride/Au nanowire nanocomposite (PEI-C3N4/AuNWs) and exonuclease-assisted signal amplification strategy was constructed for the determination of chloramphenicol (CAP). Initially, a nanocomposite with substantial electrocatalytic property was synthesized by PEI-C3N4/AuNWs. This improves the conductivity and specific surface area of the PEI-C3N4/AuNW-modified gold electrode. Next, a DNA with a complementary sequence to a CAP aptamer (cDNA) was immobilized on the PEI-C3N4/AuNW-modified electrode, followed by the CAP aptamer hybridized with cDNA. The lower signal at this time is due to the negatively charged phosphate group of the oligonucleotide and [Fe (CN)6]3-/4- electrostatically repelling each other. The presence of the CAP would cause aptamer on the electrode surface to fall off and be digested by Recjf exonuclease, which resulted in target recycling, and a significant increase in DPV signal can be observed at a potential of 0.176 V (vs. Ag/AgCl). Under optimal conditions, there is a linear relationship between the peak current and the logarithm of CAP concentration in the range 100 fM-1 µM, and the detection limit of this aptasensor is 2.96 fM (S/N = 3). Furthermore, the resultant aptasensor has excellent specificity, reproducibility, and long-term stability, and has been applied to the detection of CAP in milk samples. Graphical abstract The detection principle of the electrochemical aptasensor for CAP detection was based on PEI-C3N4/AuNWs and exonuclease-assistant signal amplification. It is based on the fact that PEI-C3N4/AuNWs nanocomposites on the surface of the electrode can effectively improve the performance of the aptasensor, and Recjf exonuclease initiates the target recycling process, causes signal amplification.


Asunto(s)
Aptámeros de Nucleótidos/química , Cloranfenicol/análisis , Exonucleasas/química , Nanocables/química , Animales , Técnicas Biosensibles/métodos , Cloranfenicol/química , Técnicas Electroquímicas/métodos , Electrodos , Contaminación de Alimentos/análisis , Oro/química , Grafito/química , Ácidos Nucleicos Inmovilizados/química , Límite de Detección , Leche/química , Compuestos de Nitrógeno/química , Polietileneimina/química , Reproducibilidad de los Resultados , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química
10.
Soft Matter ; 16(1): 162-169, 2020 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-31774104

RESUMEN

A highly stretchable nanocomposite (NC) hydrogel was fabricated via in situ free radical polymerization of acrylamide. In particular, an exfoliated two-dimensional MXene (Ti3C2) nanosheet was utilized as a crosslinker instead of traditional organic crosslinkers. The exfoliated Ti3C2 nanosheets were confirmed by atomic force microscopy (AFM) and dynamic light scattering (DLS) measurements. Compared with traditional organic crosslinked N,N-methylene bisacrylamide (BIS)/polyacrylamide (PAM) hydrogels (fracture strength of 32.0 kPa and elongation of 109.6%), the synthesized Ti3C2/PAM NC hydrogels exhibited greatly improved mechanical properties with fracture strengths of 66.5 to 102.7 kPa, compressive strengths of 400.6 to 819.4 kPa and elongations at break of 2158.6% to 3047.5% as the Ti3C2 content increases from 0.0145% to 0.0436%. The enhanced mechanical performances can be attributed to the honeycomb-like fine structure with uniform pores as well as more flexible polymer chains in NC hydrogel networks. When loaded with drugs, Ti3C2/PAM NC hydrogels exhibited good sustained-release performance, higher drug loading amounts (97.5-127.7 mg g-1) and higher percentage releases (62.1-81.4%), greatly superior to those of the BIS/PAM hydrogel (46.4 mg g-1, 45.0%). Our work reveals the application of MXene materials in the fabrication of NC hydrogels with enhanced mechanical and drug release behaviors.


Asunto(s)
Resinas Acrílicas/química , Hidrogeles/química , Nanocompuestos/química , Titanio/química , Cloranfenicol/química , Cloranfenicol/metabolismo , Portadores de Fármacos/química , Liberación de Fármacos
11.
Biochemistry (Mosc) ; 85(11): 1443-1457, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33280584

RESUMEN

Virtual screening of all possible tripeptide analogues of chloramphenicol was performed using molecular docking to evaluate their affinity to bacterial ribosomes. Chloramphenicol analogues that demonstrated the lowest calculated energy of interaction with ribosomes were synthesized. Chloramphenicol amine (CAM) derivatives, which contained specific peptide fragments from the proline-rich antimicrobial peptides were produced. It was demonstrated using displacement of the fluorescent erythromycin analogue from its complex with ribosomes that the novel peptide analogues of chloramphenicol were able to bind bacterial ribosome; all the designed tripeptide analogues and one of the chloramphenicol amine derivatives containing fragment of the proline-rich antimicrobial peptides exhibited significantly greater affinity to Escherichia coli ribosome than chloramphenicol. Correlation between the calculated and experimentally evaluated levels of the ligand efficiencies was observed. In vitro protein biosynthesis inhibition assay revealed, that the RAW-CAM analogue shows activity at the level of chloramphenicol. These data were confirmed by the chemical probing assay, according to which binding pattern of this analogue in the nascent peptide exit tunnel was similar to chloramphenicol.


Asunto(s)
Cloranfenicol/química , Escherichia coli/química , Simulación del Acoplamiento Molecular , Péptidos/química , Ribosomas/química
12.
Mikrochim Acta ; 187(9): 505, 2020 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-32815083

RESUMEN

The performance of chloramphenicol aptamer, including binding thermodynamics, structure switching, and binding domain, was investigated by isothermal titration calorimetry, circular dichroism, and molecular docking. Then, a new fluorescence aptasensor was developed with signal amplification mediated by exonuclease I-catalyzed reaction and hybridization chain reaction (HCR) for chloramphenicol detection. In this system, the aptamer-binding domain is blocked by the initiator of HCR, the aptamer undergoes structure switching in the presence of chloramphenicol, and DNA dissociation occurs. The released aptamer is subsequently recognized and cleaved by Exo I to set free chloramphenicol. With the Exo I-assisted chloramphenicol recycling, an increasing number of initiators were exposed from the digestion of the initiator-aptamer complex. Then, the chain-like assembly of FAM labeled H1 and H2 through HCR was triggered by the initiator, generating a long DNA polymer. Under optimum conditions, the aptasensor exhibited a log-linear range from 0.001 to 100 nM of chloramphenicol and a detection limit of 0.3 pM. Additionally, the designed biosensing platform was applied to determine chloramphenicol in milk and lake water with high accuracy. The current approach provides a new avenue to develop sensitive aptasensors with the assistance of binding mechanism between aptamer and target compounds. Graphical abstract.


Asunto(s)
Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Cloranfenicol/análisis , Animales , Aptámeros de Nucleótidos/metabolismo , Cloranfenicol/química , Cloranfenicol/metabolismo , ADN/química , Exodesoxirribonucleasas/química , Fluorescencia , Contaminación de Alimentos/análisis , Lagos/análisis , Límite de Detección , Leche/química , Simulación del Acoplamiento Molecular , Técnicas de Amplificación de Ácido Nucleico , Espectrometría de Fluorescencia
13.
Mikrochim Acta ; 187(6): 319, 2020 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-32394282

RESUMEN

A sensitive and selective method for the determination of the antibiotic chloramphenicol (CAP) is described, which is based on double signal amplification and GO as an efficient fluorescence quencher. The nucleic acid probe is composed of three well-defined regions, viz. the signal probe I, the signal probe II, and the capture probe. The capture probe will bind to CAP specifically and the signal probes produce a significant fluorescence signal. One end of the signal probes is labeled with the fluorophore 6-carboxyfluorescein (FAM). The labeled probes can be adsorbed on graphene oxide (GO) via π-stacking interactions, upon which the green fluorescence of FAM (measured at excitation/emission wavelengths of 490/514 nm) is quenched. On addition of CAP, the aptamer/CAP complexes are formed, and this leads to the restoration of fluorescence due to the removal of the probes from GO. The double signal probes, together with GO as quencher, improve the fluorescence signal significantly and lower the detection limit. Under optimized conditions, the assay works in the 20- to 200-ppb CAP concentration range and has a 0.3-ppb detection limit. It is also successfully applied to the determination of CAP in spiked swine urine samples. The recoveries from spiked swine urine samples are between 97.73 and 108.56%, and the repeatability (expressed as the RSD) is between 4.66 and 8.90%. Graphical abstract The constructed DNA probes form a stable structure and bind to chloramphenicol specifically. One end of signal probes was labeled with the fluorophore 6-carboxyfluorescein (FAM). The detection sensitivity of chloramphenicol was significantly enhanced by using double signal amplification, which was superior to the traditional methods. The quantities of CAP can be achieved by fluorescence increment.


Asunto(s)
Antibacterianos/orina , Cloranfenicol/orina , Grafito/química , Animales , Antibacterianos/química , Aptámeros de Nucleótidos/química , Secuencia de Bases , Cloranfenicol/química , Sondas de ADN/química , Fluoresceínas/química , Colorantes Fluorescentes/química , Ácidos Nucleicos Inmovilizados/química , Límite de Detección , Espectrometría de Fluorescencia/métodos , Porcinos
14.
Mikrochim Acta ; 187(8): 437, 2020 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-32647943

RESUMEN

Gold nanoparticles (AuNPs) conjugated with Cy3-tagged aptamer which can specifically recognize chloramphenicol (CAP) (referred to as AuNPs-AptCAP) are described. CAP can trigger the configuration change of CAP binding aptamer, and thus switching the fluorescence of AuNPs-AptCAP through changing the efficiency of the fluorescence resonance energy transfer (FRET) system with Cy3 as donors and AuNPs as recipients. AuNPs-AptCAP exhibits a linear range of CAP concentrations from 26.0 to 277 µg L-1 with a limit of detection of 8.1 µg L-1 when Cy3 was excited at 530 nm and emission was measured at 570 nm. More importantly, AuNPs-AptCAP can be utilized as signal transducers for the build-up of a series of logic gates including YES, PASS 0, INH, NOT, PASS 1, and NAND. Utilizing the principle of a metal ion-mediated fluorescence switch together with a strong metal ion chelator, the fluorescence of AuNPs-AptCAP could be modulated by adding metal ions and EDTA sequentially. Therefore, a "Plug and Play" logic system based on AuNPs-AptCAP has been realized by simply adding other components to create new logic functions. This work highlights the advantages of simple synthesis and facile fluorescence switching properties, which will provide useful knowledge for the establishment of molecular logic systems. Graphical abstract.


Asunto(s)
Aptámeros de Nucleótidos/química , Carbocianinas/química , Colorantes Fluorescentes/química , Lógica , Nanopartículas del Metal/química , Secuencia de Bases , Cloranfenicol/química , ADN/química , Ácido Edético/química , Fluorescencia , Transferencia Resonante de Energía de Fluorescencia , Oro/química , Ácidos Nucleicos Inmovilizados/química , Límite de Detección , Mercurio/química , Níquel/química
15.
Int J Mol Sci ; 21(11)2020 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-32532004

RESUMEN

Molecular imprinting technology is a promising method for detecting chloramphenicol (CAP), a broad-spectrum antibiotic with potential toxicity to humans, in animal-derived foods. This work aimed to investigate the interactions between the CAP as a template and functional monomers required for synthesizing efficient molecularly imprinted polymers for recognition and isolation of CAP based on density functional theory. The most suitable monomer, methacrylic acid (MAA), was determined based on interaction energies and Gibbs free energy changes. Further, the reaction sites of CAP and MAA was predicted through the frontier molecular orbitals and molecular electrostatic potentials. Atoms in molecules topology analysis and non-covalent interactions reduced density gradient were applied to investigate different types of non-covalent and inter-atomic interactions. The simulation results showed that CAP was the main electron donor, while MAA was the main electron acceptor. Moreover, the CAP-MAA complex simultaneously involved N-H···O and C=O···H double hydrogen bonds, where the strength of the latter was greater than that of the former. The existence of hydrogen bonds was also confirmed by theoretical and experimental hydrogen nuclear magnetic resonance and Fourier transform infrared spectroscopic analyses. This research can act as an important reference for intermolecular interactions and provide strong theoretical guidance regarding CAP in the synthesis of molecularly imprinted polymers.


Asunto(s)
Cloranfenicol/química , Metacrilatos/química , Polímeros Impresos Molecularmente/química , Teoría Funcional de la Densidad , Espectroscopía de Resonancia Magnética , Solventes/química , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática
16.
Artículo en Inglés | MEDLINE | ID: mdl-30962327

RESUMEN

This year marks the 70th anniversary since Parke-Davis and Company announced the synthesis of chloramphenicol, the first naturally occurring antibiotic to be chemically generated in vitro for large-scale production. The effort was led by the chemist Mildred Rebstock, Ph.D., (1919 to 2011), who would turn 100 years old this year. Her accomplishment, at a time when very few chemists in the United States were women, was celebrated internationally. This commentary reviews her important contribution.


Asunto(s)
Cloranfenicol/química , Cloranfenicol/síntesis química , Antibacterianos/síntesis química , Antibacterianos/química , Femenino , Humanos
17.
Bioorg Med Chem Lett ; 29(9): 1127-1132, 2019 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-30826292

RESUMEN

Chloramphenicol nitroreductase (CNR), a drug-modifying enzyme from Haemophilus influenzae, has been shown to be responsible for the conversion of the nitro group into an amine in the antibiotic chloramphenicol (CAM). Since CAM structurally bears a 4-nitrobenzene moiety, we explored the substrate promiscuity of CNR by investigating its nitroreduction of 4-nitrobenzyl derivatives. We tested twenty compounds containing a nitrobenzene core, two nitropyridines, one compound with a vinylogous nitro group, and two aliphatic nitro compounds. In addition, we also synthesized twenty-eight 4-nitrobenzyl derivatives with ether, ester, and thioether substituents and assessed the relative activity of CNR in their presence. We found several of these compounds to be modified by CNR, with the enzyme activity ranging from 1 to 150% when compared to CAM. This data provides insights into two areas: (i) chemoenzymatic reduction of select compounds to avoid harsh chemicals and heavy metals routinely used in reductions of nitro groups and (ii) functional groups that would aid CAM in overcoming the activity of this enzyme.


Asunto(s)
Cloranfenicol/metabolismo , Haemophilus influenzae/enzimología , Nitrobencenos/metabolismo , Nitrorreductasas/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacología , Cloranfenicol/química , Cloranfenicol/farmacología , Farmacorresistencia Bacteriana , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Nitrobencenos/química , Nitrobencenos/farmacología , Relación Estructura-Actividad
18.
Proc Natl Acad Sci U S A ; 113(43): 12150-12155, 2016 10 25.
Artículo en Inglés | MEDLINE | ID: mdl-27791002

RESUMEN

The first broad-spectrum antibiotic chloramphenicol and one of the newest clinically important antibacterials, linezolid, inhibit protein synthesis by targeting the peptidyl transferase center of the bacterial ribosome. Because antibiotic binding should prevent the placement of aminoacyl-tRNA in the catalytic site, it is commonly assumed that these drugs are universal inhibitors of peptidyl transfer and should readily block the formation of every peptide bond. However, our in vitro experiments showed that chloramphenicol and linezolid stall ribosomes at specific mRNA locations. Treatment of bacterial cells with high concentrations of these antibiotics leads to preferential arrest of translation at defined sites, resulting in redistribution of the ribosomes on mRNA. Antibiotic-mediated inhibition of protein synthesis is most efficient when the nascent peptide in the ribosome carries an alanine residue and, to a lesser extent, serine or threonine in its penultimate position. In contrast, the inhibitory action of the drugs is counteracted by glycine when it is either at the nascent-chain C terminus or at the incoming aminoacyl-tRNA. The context-specific action of chloramphenicol illuminates the operation of the mechanism of inducible resistance that relies on programmed drug-induced translation arrest. In addition, our findings expose the functional interplay between the nascent chain and the peptidyl transferase center.


Asunto(s)
Cloranfenicol/farmacología , Escherichia coli/efectos de los fármacos , Linezolid/farmacología , Peptidil Transferasas/antagonistas & inhibidores , Biosíntesis de Proteínas , Ribosomas/efectos de los fármacos , Aminoácidos/genética , Aminoácidos/metabolismo , Sitios de Unión , Cloranfenicol/química , Escherichia coli/genética , Escherichia coli/metabolismo , Linezolid/química , Modelos Moleculares , Peptidil Transferasas/genética , Peptidil Transferasas/metabolismo , Unión Proteica , ARN Mensajero/genética , ARN Mensajero/metabolismo , Aminoacil-ARN de Transferencia/genética , Aminoacil-ARN de Transferencia/metabolismo , Ribosomas/genética , Ribosomas/metabolismo
19.
Mikrochim Acta ; 187(1): 10, 2019 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-31797114

RESUMEN

A lateral-flow immunochromatographic assay with excellent sensitivity and wide application potential is described. The bovine serum albumin (BSA) antibody was immobilized in the test line for universality, and preincubation was introduced for high method sensitivity. Carboxy-modified CdSe/ZnS core-shell nanoparticles were used as label, and the fluorescence peaking at 605 nm was detected. The fluorescence in the test line was negative against the relevant analyte content. The chloramphenicol (CAP) and the aflatoxin M1 (AFM1) in milk were detected using the same strip to validate the universality. After optimization, the detection limit for CAP is 10 pg·mL-1, which is three times less that of a conventional assay (30 pg·mL-1). The detection limit for AFM1 was 6 pg·mL-1, which was 13 times less than that of a conventional assay (8 pg·mL-1). The method was applied in the analysis of spiked milk samples. The performance was compared with that of the commercial ELISA kit, and good agreement was observed. Graphical abstractSchematic representation of the universal and sensitive combined immunochromatographic assay (USICA) and conventional immunochromatographic assay (TICA) of chloramphenicol (CAP) and aflatoxin M1.


Asunto(s)
Aflatoxina M1/análisis , Anticuerpos Inmovilizados/química , Compuestos de Cadmio/química , Cloranfenicol/análisis , Inmunoensayo/métodos , Nanopartículas/química , Compuestos de Selenio/química , Sulfuros/química , Compuestos de Zinc/química , Aflatoxina M1/química , Anticuerpos Inmovilizados/inmunología , Cloranfenicol/química , Límite de Detección , Albúmina Sérica Bovina/inmunología
20.
Int J Mol Sci ; 20(20)2019 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-31614695

RESUMEN

Chloramphenicol (CAM) has been encapsulated into hydroxyapatite nanoparticles displaying different morphologies and crystallinities. The process was based on typical precipitation of solutions containing phosphate and calcium ions and the addition of CAM once the hydroxyapatite nuclei were formed. This procedure favored a disposition of the drug into the bulk parts of the nanoparticles and led to a fast release in aqueous media. Clear antibacterial activity was derived, being slightly higher for the amorphous samples due to their higher encapsulation efficiency. Polylactide (PLA) microfibers incorporating CAM encapsulated in hydroxyapatite nanoparticles were prepared by the electrospinning technique and under optimized conditions. Drug release experiments demonstrated that only a small percentage of the loaded CAM could be delivered to an aqueous PBS medium. This amount was enough to render an immediate bacteriostatic effect without causing a cytotoxic effect on osteoblast-like, fibroblasts, and epithelial cells. Therefore, the prepared scaffolds were able to retain CAM-loaded nanoparticles, being a reservoir that should allow a prolonged release depending on the polymer degradation rate. The studied system may have promising applications for the treatment of cancer since CAM has been proposed as a new antitumor drug.


Asunto(s)
Antibacterianos/farmacología , Cloranfenicol/farmacología , Durapatita/química , Poliésteres/química , Animales , Antibacterianos/química , Cápsulas , Línea Celular , Cloranfenicol/química , Chlorocebus aethiops , Escherichia coli/efectos de los fármacos , Nanopartículas , Tamaño de la Partícula , Staphylococcus aureus/efectos de los fármacos , Células Vero
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA