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1.
J Environ Manage ; 362: 121330, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38833927

RESUMEN

Fluoroquinolone antibiotics and antibiotic resistance genes (ARGs) regarded as emerging contaminants were poorly removed in conventional wastewater treatment plants (WWTPs). Nitrogen-containing heterocyclic organics were found to be biodegraded through denitrification co-metabolism. The feasibility to enhance antibiotics removal efficiency in WWTPs through denitrification co-metabolism needs to be further verified. Meanwhile, due to significant correlation between ARGs profiles and nitrogen removal that was previously observed, the dissemination of ARGs during denitrification was worthy of in-depth understanding. Herein, the antibiotic removal and ARGs dissemination in denitrification co-metabolism condition were investigated with different denitrifying consortiums that acclimated under different conditions in terms of carbon source and the exposure of Ofloxacin (OFL). The results suggest that the removal of OFL can be enhanced by the denitrification co-metabolism. The tolerance to OFL is different among various denitrifying communities. For the denitrifying consortiums acclimated with methanol, long-term exposure to trace OFL (1 µg/L) could reduce the capabilities of removal and tolerance to OFL. On the contrary, those acclimated with sodium acetate (NaAc), the capabilities of removal and tolerance to OFL, were enhanced by long-term exposure to trace OFL. According to the quantitative determination to 384 target genes with high-throughput quantitative PCR, the abundance of ARGs in consortiums greatly increased when exposed to OFL at the concentration of comparable to sewage, which was also much larger than that acclimated with methanol. It can be confirmed and supported by DNA sequencing results that the antibiotic removal and the dissemination of ARGs were determined by microbial community that could be shaped with carbon source. These conclusions suggest that selecting the right external carbon source can be a useful strategy for WWTPs to control antibiotics and ARGs in the effluent. From a new perspective on mitigating ARGs dissemination, NaAc was not an appropriate carbon source.


Asunto(s)
Antibacterianos , Carbono , Desnitrificación , Farmacorresistencia Microbiana , Aguas Residuales , Farmacorresistencia Microbiana/genética , Nitrógeno/metabolismo
2.
J Pharmacol Exp Ther ; 384(2): 315-325, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36396352

RESUMEN

Targeting neuronal Kv7 channels by pharmacological activation has been proven to be an attractive therapeutic strategy for epilepsy. Here, we show that activation of Kv7 channels by an opener SCR2682 dose-dependently reduces seizure activity and severity in rodent models of epilepsy induced by a GABAa receptor antagonist pentylenetetrazole (PTZ), maximal electroshock, and a glutamate receptor agonist kainic acid (KA). Electroencephalographic recordings of rat cerebral cortex confirm that SCR2682 also decreases epileptiform discharges in KA-induced seizures. Nissl and neuronal nuclei staining further demonstrates that SCR2682 also protects neurons from injury induced by KA. In Morris water maze navigation and Y-maze tests, SCR2682 improves PTZ- and KA-induced cognitive impairment. Taken together, our findings demonstrate that pharmacological activation of Kv7 by novel opener SCR2682 may hold promise for therapy of epilepsy with cognitive impairment. SIGNIFICANCE STATEMENT: A neuronal Kv7 channel opener SCR2682 attenuates epileptogenesis and seizure-induced cognitive impairment in rodent models of seizures, thus possessing a developmental potential for effective therapy of epilepsy with cognitive impairment.


Asunto(s)
Disfunción Cognitiva , Epilepsia , Ratas , Animales , Anticonvulsivantes/uso terapéutico , Roedores , Convulsiones/inducido químicamente , Convulsiones/tratamiento farmacológico , Epilepsia/inducido químicamente , Epilepsia/tratamiento farmacológico , Disfunción Cognitiva/tratamiento farmacológico , Disfunción Cognitiva/etiología , Pentilenotetrazol/toxicidad , Cognición , Modelos Animales de Enfermedad
3.
Chembiochem ; 23(7): e202100697, 2022 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-35146861

RESUMEN

The enzyme formaldehyde dehydrogenase (FalDH) from Pseudomonas putida is of particular interest for biotechnological applications as it catalyzes the oxidation of formaldehyde independent of glutathione. However, the consumption of a stoichiometric amount of nicotinamide adenine dinucleotide (NAD) can be challenging at the metabolic level as this may affect many other NAD-linked processes. A potential solution is to engineer FalDH to utilize non-natural cofactors. Here we devised FalDH variants to favor nicotinamide cytosine dinucleotide (NCD) by structure-guided modification of the binding pocket for the adenine moiety of NAD. Several mutants were obtained and the best one FalDH 9B2 had over 150-fold higher preference for NCD than NAD. Molecular docking analysis indicated that the cofactor binding pocket shrunk to better fit NCD, a smaller-sized cofactor. FalDH 9B2 together with other NCD-linked enzymes offer opportunities to assemble orthogonal pathways for biological conversion of C1 molecules.


Asunto(s)
Pseudomonas putida , Aldehído Oxidorreductasas , Citosina , Formaldehído , Simulación del Acoplamiento Molecular , NAD/química , Niacinamida/química
4.
Inorg Chem ; 61(29): 11293-11305, 2022 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-35820030

RESUMEN

Lu2(1-x)Eu2xO3 nanoscintillators (x = 0.005, 0.01, 0.03, 0.05, 0.07, and 0.10) with red emission were synthesized by a coprecipitation method. It is found that their photo- and radioluminescence intensities increase with increasing Eu3+ concentration until x = 0.05. According to their concentration-dependent luminescence intensity ratios (I610(C2)/I582(S6)), the existing energy transfer from Eu3+(S6) (occupying S6 sites) to Eu3+(C2) (occupying C2 sites) can be confirmed. Based on the spectral data and density functional theory (DFT) calculations, the origin of Lu2O3:Eu3+ persistent luminescence at low concentration might be related to the tunneling processes between Eu3+ (occupying C2 and S6 sites) and oxygen interstitials (Oi×). After dispersing afterglow-suppressed Lu2O3:Eu3+ nanoscintillators into polymethyl methacrylate (PMMA) polymer-acetone solution, flexible PMMA-Lu2O3:Eu3+ composite films with high thermal stability and radiation resistance were fabricated by a doctor blade method. As the flexible composite film was used as an imaging plate, static X-ray images with high spatial resolution (5.5 lp/mm) under an extremely low dose of ∼1.1 µGyair can be acquired. When a watch with a moving second hand was used as an object, the dynamic X-ray imaging can be realized under a dose rate of 55 µGyair·s-1. Our results demonstrate that Lu2O3:Eu3+ nanoscintillators can be regarded as candidate materials for dynamic digital radiographic imaging.


Asunto(s)
Europio , Polimetil Metacrilato , Transferencia de Energía , Luminiscencia , Rayos X
5.
AAPS PharmSciTech ; 23(5): 136, 2022 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-35534759

RESUMEN

The present work was to construct a roflumilast (ROF) cream for the treatment of psoriasis and clarify the dual roles of propylene glycol monocaprylate (PGM) in both molecular mobility of the cream, and drug-skin miscibility via drug-PGM-ceramide and drug-PGM-collagen intermolecular interaction. The cream formulation was screened through the stability study and in vitro skin administration study, optimized by Plackett-Burman and Box-Behnken design, and finally verified by the in vivo tissue distribution study. PGM demonstrated a significant drug skin retention enhancement effect (Rmax in vivo = 19.5 µg/g). It increased the molecular mobility of the oil phase of the cream by decreasing the molecular interaction of oil molecules proven by the rheology study (Ec = 3.73 × 10-4 mJ·m-3). More importantly, because of the good stratum corneum (SC) compatibility (∆H = - 403.88 J/g), PGM promoted an orderly flow of SC lipids (X-ray scattering, ΔLPP = 1.18 nm) and entered the viable epidermis/dermis (VE/DE) in large quantities (RPGM = 1186 µg/g), acting as a bridge to connect the drug to collagen through two H-bonds (LengthH-bond = 2.846 Å and 3.313 Å), thus increasing the miscibility of drug and VE/DE significantly (∆H = - 310.10 J/g, Emix = 21.66 kcal/mol). In this study, a ROF cream was developed successfully and the effect of PGM on the skin retention was clarified at molecular level.


Asunto(s)
Aminopiridinas , Piel , Aminopiridinas/farmacología , Benzamidas , Colágeno/farmacología , Ciclopropanos , Preparaciones Farmacéuticas , Propilenglicol/química , Glicoles de Propileno , Crema para la Piel
6.
Chembiochem ; 22(10): 1765-1768, 2021 05 14.
Artículo en Inglés | MEDLINE | ID: mdl-33523590

RESUMEN

The use of nicotinamide cytosine dinucleotide (NCD), a biocompatible nicotinamide adenosine dinucleotide (NAD) analogue, is of great scientific and biotechnological interest. Several redox enzymes have been devised to favor NCD, and have been successfully applied in creating NCD-dependent redox systems. However, molecular interactions between cofactor and protein have still to be disclosed in order to guide further engineering efforts. Here we report the structural analysis of an NCD-favoring malic enzyme (ME) variant derived from Escherichia coli. The X-ray crystal structure data revealed that the residues located at position 346 and 401 in ME acted as the "gatekeepers" of the adenine moiety binding cavity. When Arg346 was substituted with either acidic or aromatic residues, the corresponding mutants showed substantially reduced NCD preference. Inspired by these observations, we generated Lactobacillus helveticus derived d-lactate dehydrogenase variants at Ile177, the counterpart to Arg346 in ME, and found a similar trend in terms of cofactor preference changes. As many NAD-dependent oxidoreductases share key structural features, our results provide guidance for protein engineering to obtain more NCD-favoring variants.


Asunto(s)
Proteínas Bacterianas/metabolismo , Malato Deshidrogenasa/metabolismo , NAD/química , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Sitios de Unión , Cristalografía por Rayos X , Escherichia coli/enzimología , L-Lactato Deshidrogenasa/química , L-Lactato Deshidrogenasa/genética , L-Lactato Deshidrogenasa/metabolismo , Lactobacillus helveticus/enzimología , Malato Deshidrogenasa/química , Simulación de Dinámica Molecular , Mutagénesis Sitio-Dirigida , NAD/metabolismo , Oxidación-Reducción
7.
Metab Eng ; 66: 157-166, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33823272

RESUMEN

The chain length (CL) of fatty acids (FAs) is pivotal to oil property, yet to what extent it can be customized in industrial oleaginous microalgae is unknown. In Nannochloropsis oceanica, to modulate long-chain FAs (LCFAs), we first discovered a fungi/bacteria-originated polyketide synthase (PKS) system which involves a cytoplasmic acyl-ACP thioesterase (NoTE1). NoTE1 hydrolyzes C16:0-, C16:1- and C18:1-ACP in vitro and thus intercepts the specific acyl-ACPs elongated by PKS for polyunsaturated FA biosynthesis, resulting in elevation of C16/C18 monounsaturated FAs when overproduced and increase of C20 when knocked out. For medium-chain FAs (MCFAs; C8-C14), C8:0 and C10:0 FAs are boosted by introducing a Cuphea palustris acyl-ACP TE (CpTE), whereas C12:0 elevated by rationally engineering CpTE enzyme's substrate-binding pocket to shift its CL preference towards C12:0. A mechanistic model exploiting both native and engineered PKS and type II FAS pathways was thus proposed for manipulation of carbon distribution among FAs of various CL. The ability to tailor FA profile at the unit CL resolution from C8 to C20 in Nannochloropsis spp. lays the foundation for scalable production of designer lipids via industrial oleaginous microalgae.


Asunto(s)
Microalgas , Estramenopilos , Ácidos Grasos , Lípidos , Microalgas/genética , Sintasas Poliquetidas , Estramenopilos/genética
8.
Chembiochem ; 21(14): 1972-1975, 2020 07 16.
Artículo en Inglés | MEDLINE | ID: mdl-32175634

RESUMEN

Synthetic nicotinamide adenine dinucleotide (NAD) analogues are of great scientific and biotechnological interest. One such analogue, nicotinamide cytosine dinucleotide (NCD), has been successfully applied to creating bioorthogonal redox systems. Yet, only a few redox enzymes have been devised to favor NCD. We have engineered Lactobacillus helveticus-derived NAD-dependent d-lactate dehydrogenase (LhDLDH) to favor NCD by semirational design. Sequence alignment and structural analysis revealed that amino acid residues I177 and N213 form a "gate" guarding the NAD adenine moiety binding cavity. Saturated mutagenesis libraries were constructed by using the mutant LhDLDH-V152R as the parental sequence. Mutants were obtained with good catalytic efficiency, and NCD preference increased by up to 940-fold. Experiments showed that Escherichia coli cells expressing mutants with higher NCD preference afforded much less d-lactate, thus suggesting the potential to construct NCD-mediated orthogonal metabolism.


Asunto(s)
Lactato Deshidrogenasas/metabolismo , NAD/biosíntesis , Ingeniería de Proteínas , Secuencia de Aminoácidos , Lactato Deshidrogenasas/química , Lactato Deshidrogenasas/genética , Lactobacillus helveticus/enzimología , Modelos Moleculares , Conformación Molecular , Mutación , NAD/química , Alineación de Secuencia
9.
Chemistry ; 26(70): 16611-16615, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-32815230

RESUMEN

Formate dehydrogenase (FDH) has been widely used for the regeneration of the reduced nicotinamide adenine dinucleotide (NADH). To utilize nicotinamide cytosine dinucleotide (NCD) as a non-natural redox cofactor, it remains challenging as NCDH, the reduced form of NCD, has to be efficiently regenerated. Here we demonstrate successful engineering of FDH for NCDH regeneration. Guided by the structural information of FDH from Pseudomonas sp. 101 (pseFDH) and the NAD-pseFDH complex, semi-rational strategies were applied to design mutant libraries and screen for NCD-linked activity. The most active mutant reached a cofactor preference switch from NAD to NCD by 3700-fold. Homology modeling analysis showed that these mutants had reduced cofactor binding pockets and dedicated hydrophobic interactions for NCD. Efficient regeneration of NCDH was implemented by powering an NCD-dependent D-lactate dehydrogenase for stoichiometric and stereospecific reduction of pyruvate to D-lactate at the expense of formate.


Asunto(s)
Formiato Deshidrogenasas/química , Formiato Deshidrogenasas/metabolismo , NAD/metabolismo , Formiato Deshidrogenasas/genética , L-Lactato Deshidrogenasa/metabolismo , Oxidación-Reducción
10.
Angew Chem Int Ed Engl ; 59(8): 3143-3146, 2020 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-31845497

RESUMEN

A non-natural cofactor and formate driven system for reductive carboxylation of pyruvate is presented. A formate dehydrogenase (FDH) mutant, FDH*, that favors a non-natural redox cofactor, nicotinamide cytosine dinucleotide (NCD), for generation of a dedicated reducing equivalent at the expense of formate were acquired. By coupling FDH* and NCD-dependent malic enzyme (ME*), the successful utilization of formate is demonstrated as both CO2 source and electron donor for reductive carboxylation of pyruvate with a perfect stoichiometry between formate and malate. When 13 C-isotope-labeled formate was used in in vitro trials, up to 53 % of malate had labeled carbon atom. Upon expression of FDH* and ME* in the model host E. coli, the engineered strain produced more malate in the presence of formate and NCD. This work provides an alternative and atom-economic strategy for CO2 fixation where formate is used in lieu of CO2 and offers dedicated reducing power.

11.
Am J Physiol Renal Physiol ; 317(6): F1582-F1592, 2019 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-31532246

RESUMEN

Cisplatin is a commonly used chemotherapeutic drug for cancer treatment, but its nephrotoxicity may lead to the deterioration of renal function. Previous work has been focused on cisplatin-induced acute kidney disease, whereas the mechanism of chronic kidney disease after cisplatin chemotherapy is largely unknown. In the present study, we have characterized the mouse model of chronic kidney defects induced by repeated low-dose cisplatin treatment. We have also established a relevant cell culture model. In the animal model, C57 mice were given weekly injection of 8 mg/kg cisplatin for 4 wk. This led to a sustained decline of kidney function. These mice showed loss of kidney mass, interstitial fibrosis, continued activation of inflammatory cytokines, and appearance of atubular glomeruli. In the cell model, the BUMPT mouse proximal tubular cell line was treated four times with 1-2 µM cisplatin, resulting in low levels of apoptosis and the expression of fibrosis proteins and profibrotic factors. These data suggest that repeated treatment with low-dose cisplatin causes long-term renal pathologies with characteristics of chronic kidney disease.


Asunto(s)
Antineoplásicos/toxicidad , Cisplatino/toxicidad , Túbulos Renales/efectos de los fármacos , Riñón/efectos de los fármacos , Insuficiencia Renal Crónica/inducido químicamente , Animales , Apoptosis/efectos de los fármacos , Células Cultivadas , Citocinas , Fibrosis , Tasa de Filtración Glomerular , Riñón/patología , Pruebas de Función Renal , Glomérulos Renales/patología , Túbulos Renales/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Tamaño de los Órganos , Insuficiencia Renal Crónica/patología
12.
Bioorg Med Chem Lett ; 29(12): 1446-1449, 2019 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-31006524

RESUMEN

Many alcohol dehydrogenases (ADHs) catalyze oxidation of a broad scope of alcohols. When an NAD-dependent ADH oxidizes methanol, albeit at a poor rate, it may be treated as methanol dehydrogenase (MDH). One ADH from Geobacillus stearothermophilus DSM 2334 (GsADH) has been widely used as MDH, but its actual substrate scope remains less characterized. Here we purified recombinant GsADH from Escherichia coli and determined its crystal structure. We collected kinetics data of this enzyme towards a number of short chain alcohols, and found that isopropanol is by far the most favorable substrate. Moreover, molecular docking analysis suggested that substrate preference is mainly attributed to the conformer energy of the protein-substrate complex. Our data clarified the substrate scope of GsADH and provided structural insights, which may facilitate more efficient cofactor regeneration and rational metabolic engineering.


Asunto(s)
Alcohol Deshidrogenasa/metabolismo , Oxidorreductasas de Alcohol/metabolismo , Secuencia de Aminoácidos , Humanos , Simulación del Acoplamiento Molecular
13.
Appl Environ Microbiol ; 83(13)2017 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-28455340

RESUMEN

NAD and its reduced form NADH function as essential redox cofactors and have major roles in determining cellular metabolic features. NAD can be synthesized through the deamidated and amidated pathways, for which the key reaction involves adenylylation of nicotinic acid mononucleotide (NaMN) and nicotinamide mononucleotide (NMN), respectively. In Escherichia coli, NAD de novo biosynthesis depends on the protein NadD-catalyzed adenylylation of NaMN to nicotinic acid adenine dinucleotide (NaAD), followed by NAD synthase-catalyzed amidation. In this study, we engineered NadD to favor NMN for improved amidated pathway activity. We designed NadD mutant libraries, screened by a malic enzyme-coupled colorimetric assay, and identified two variants, 11B4 (Y84V/Y118D) and 16D8 (A86W/Y118N), with a high preference for NMN. Whereas in the presence of NMN both variants were capable of enabling the viability of cells of E. coli BW25113-derived NAD-auxotrophic strain YJE003, for which the last step of the deamidated pathway is blocked, the 16D8 expression strain could grow without exogenous NMN and accumulated a higher cellular NAD(H) level than BW25113 in the stationary phase. These mutants established fully active amidated NAD biosynthesis and offered a new opportunity to manipulate NAD metabolism for biocatalysis and metabolic engineering.IMPORTANCE Adenylylation of nicotinic acid mononucleotide (NaMN) and adenylylation of nicotinamide mononucleotide (NMN), respectively, are the key steps in the deamidated and amidated pathways for NAD biosynthesis. In most organisms, canonical NAD biosynthesis follows the deamidated pathway. Here we engineered Escherichia coli NaMN adenylyltransferase to favor NMN and expressed the mutant enzyme in an NAD-auxotrophic E. coli strain that has the last step of the deamidated pathway blocked. The engineered strain survived in M9 medium, which indicated the implementation of a functional amidated pathway for NAD biosynthesis. These results enrich our understanding of NAD biosynthesis and are valuable for manipulation of NAD homeostasis for metabolic engineering.


Asunto(s)
Escherichia coli/enzimología , NAD/biosíntesis , Nicotinamida-Nucleótido Adenililtransferasa/genética , Escherichia coli/química , Escherichia coli/genética , Escherichia coli/metabolismo , Mutación , NAD/análogos & derivados , NAD/metabolismo , Mononucleótido de Nicotinamida/análogos & derivados , Mononucleótido de Nicotinamida/metabolismo , Nicotinamida-Nucleótido Adenililtransferasa/química , Nicotinamida-Nucleótido Adenililtransferasa/metabolismo , Ingeniería de Proteínas , Especificidad por Sustrato
14.
Phys Chem Chem Phys ; 19(36): 24513-24521, 2017 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-28721421

RESUMEN

Spinel-phase Zn2Ga2.98-xGe0.75O8:Cr0.020,Prx (ZGGO:Cr3+,Pr3+) near infrared (NIR) persistent luminescence nanoparticles (PLNPs) with different amounts of Pr3+ dopant were prepared by a hydrothermal method in combination with a subsequent annealing in a vacuum. For these nanoparticles, the averaged particle size decreases from 64 to 37 nm with increasing Pr3+ doping concentration from 0 to 0.025 and Cr3+ and Pr3+ ions are uniformly doped into the interior and surface of a single nanoparticle. It can be found that Pr3+ doping leads to the appearance of more anti-site pairs () around distorted octahedral Cr3+ ions and enhanced NIR emissions around 697 nm, which originate from the 2E(2G) → 4A2(4F) and 4T2(4F) → 4A2(4F) transitions of the interior and surface Cr3+ ions in the nanoparticles. In particular, for the interior Cr3+ ions in the Pr3+ doped nanoparticles, the enhanced NIR luminescence can be attributed to the suppressed energy transfer of the excited electrons from the 4T2(4F) level to the trap level related to anti-site pairs () around the distorted octahedral Cr3+ ions. Our results suggest that Pr3+ doped ZGGO:Cr3+ PLNPs have potential applications for bio-imaging.


Asunto(s)
Técnicas Biosensibles , Nanopartículas , Cromo , Galio , Luminiscencia , Tamaño de la Partícula
15.
Phys Chem Chem Phys ; 19(20): 12647-12654, 2017 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-28352885

RESUMEN

Encaged-OH--free Ca12(1-x)Sr12xAl14O33:0.1%Gd3+ conductive phosphors were prepared through a melt-solidification process in combination with a subsequent heat treatment. Absorption spectra showed that the maximum encaged-electron concentration was increased to 1.08 × 1021 cm-3 through optimizing the doping amount of Sr2+ (x = 0.005). Meanwhile, FTIR and Raman spectra indicated that pure Ca11.94Sr0.06Al14O33:0.1%Gd3+ conductive phosphor without encaged OH- and C22- anions was acquired. For the conductive powders heat-treated in air for different times, the encaged-electron concentrations were tuned from 1.02 × 1021 to 8.3 × 1020 cm-3. ESR, photoluminescence, and luminescence kinetics analyses indicated that the emission at 312 nm mainly originated from Gd3+ ions surrounded by encaged O2- anions, while Gd3+ ions surrounded by encaged electrons had a negative contribution to the UV emission due to the existence of an energy transfer process. Under low-voltage electron-beam excitation (3 kV), enhanced cathodoluminescence (CL) of the conductive phosphors could be achieved by tuning the encaged-electron concentrations. In particular, for the encaged-OH--free conductive phosphor, the emission intensity of the CL was about one order of magnitude higher than that of the conductive phosphor containing encaged OH- anions. Our results suggested that the encaged-OH--free conductive phosphors have potential application in low-voltage FEDs.

16.
Phys Chem Chem Phys ; 18(28): 18697-704, 2016 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-27079823

RESUMEN

Conductive C12A7:0.1%Gd(3+),y%Sr(2+) powders with different Sr(2+) doping concentrations have been prepared in a H2 atmosphere by a solid state method in combination with subsequent UV-irradiation. The encaged electron concentration could be modulated through tuning Sr(2+) doping and its maximum value reaches 2.3 × 10(19) cm(-3). This is attributed to the competition between enhanced uptake and the release of the encaged anions during their formation and diffusion processes and the suppression of encaged electrons generation due to the increased encaged OH(-) anions and the decreased encaged O(2-) anions. Although there exists encaged electrons and different encaged anions (O(2-), H(-) and OH(-)) in C12A7 conductive powders prepared through the hydrogen route, a dominant local environment around Gd(3+) could be observed using electron spin resonance (ESR) detection. It can be ascribed to the stronger coupling of the encaged OH(-) to the framework of C12A7 than those of the encaged electrons, O(2-) and H(-) anions. In addition, emission of Gd(3+) ions is enhanced under UV or low voltage electron beam excitation and a new local environment around Gd(3+) ions appears through the thermal annealing in air because of the decrease of the encaged OH(-) anions and the increase of the encaged O(2-) anions. Our results suggested that Sr(2+) doping in combination with thermal annealing in air is an effective strategy for increasing the conductive performance and enhancing the emission of rare earth ions doped into C12A7 conductive phosphors for low-voltage field emission displays (FEDs).

17.
J Hazard Mater ; 465: 133490, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38228002

RESUMEN

This study indicated that the application of a novel Fe-Mn modified rice straw biochar (Fe/Mn-RS) as soil amendment facilitated the removal of sulfamonomethoxine (SMM) in soil water microcosms, primarily via activating degradation mechanism rather than adsorption. The similar enhancement on SMM removal did not occur using rice straw biochar (RS). Comparison of Fe/Mn-RS with RS showed that Fe/Mn-RS gains new physic-chemical properties such as abundant oxygenated C-centered persistent free radicals (PFRs). In the Fe/Mn-RS microcosms, the degradation contributed 79.5-83.8% of the total SMM removal, which was 1.28-1.70 times higher than that in the RS microcosms. Incubation experiments using sterilized and non-sterilized microcosms further revealed that Fe/Mn-RS triggered both the biodegradation and abiotic degradation of SMM. For abiotic degradation of SMM, the abundant •OH generation, induced by Fe/Mn-RS, was demonstrated to be the major contributor, according to EPR spectroscopy and free radical quenching experiments. Fenton-like bio-reaction occurred in this process where Fe (Ⅲ), Mn (Ⅲ) and Mn (Ⅳ) gained electrons, resulting in oxidative hydroxylation of SMM. This work provides new insights into the impacts of biochar on the fates of antibiotics in soil water and a potential solution for preventing antibiotic residues in agricultural soil becoming a non-point source pollutant.


Asunto(s)
Oryza , Sulfamonometoxina , Agua , Suelo/química , Radical Hidroxilo , Carbón Orgánico/química , Oryza/química , Radicales Libres
18.
Sci Rep ; 12(1): 12484, 2022 07 21.
Artículo en Inglés | MEDLINE | ID: mdl-35864126

RESUMEN

Enzymes with dedicated cofactor preference are essential for advanced biocatalysis and biomanufacturing, especially when employing nonnatural nicotinamide cofactors in redox reactions. However, directed evolution of an enzyme to switch its cofactor preference is often hindered by the lack of efficient and affordable method for screening as the cofactor per se or the substrate can be prohibitively expensive. Here, we developed a growth-based selection platform to identify nonnatural cofactor-dependent oxidoreductase mutants. The growth of bacteria depended on the nicotinamide cytosine dinucleotide (NCD) mediated conversion of non-metabolizable phosphite into phosphate. The strain BW14329 lacking the ability to oxidize phosphite was suitable as host, and NCD-dependent phosphite dehydrogenase (Pdh*) is essential to the selection platform. Previously confirmed NCD synthetase with NCD synthesis capacity and NCD-dependent malic enzyme were successfully identified by using the platform. The feasibility of this strategy was successfully demonstrated using derived NCD-active malic enzyme as well as for the directed evolution of NCD synthetase in Escherichia coli. A phosphite-based screening platform was built for identification of enzymes favoring nonnatural cofactor NCD. In the future, once Pdh variants favoring other biomimetic or nonnatural cofactors are available this selection platform may be readily redesigned to attain new enzyme variants with anticipated cofactor preference, providing opportunities to further expand the chemical space of redox cofactors in chemical biology and synthetic biology.


Asunto(s)
Enzimas , Fosfitos , Enzimas/química , Escherichia coli/genética , Ligasas , NAD , Niacinamida/química , Oxidación-Reducción
19.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 40(4): 446-450, 2022 Jul 25.
Artículo en Inglés, Zh | MEDLINE | ID: mdl-38596962

RESUMEN

OBJECTIVES: This study aimed to evaluate the clinical application value of 3D printed template-guided radiofrequency thermocoagulation combined with doxorubicin injection for the treatment of trigeminal neuralgia mandibular branch. METHODS: A total of 50 patients with primary trigeminal neuralgia mandibular branch in the hospital from January 2019 to September 2020 were randomly divided into two groups: 3D printed template-guided radiofrequency thermocoagulation combined with doxorubicin injection was used as the research group (n=25), and 3D printed template guided radiofrequency thermocoagulation was used as the control group (n=25). Comparative analysis of visual analogue score (VAS) was conducted before and immediately after surgery and at 1, 3, 6, and 12 months after surgery. The Brisman efficacy evaluation criteria for trigeminal neuralgia was used to evaluate the therapeutic effect of each postoperative follow-up period, and postoperative complications were observed. RESULTS: The VAS immediately after surgery and at 1, 3, 6, and 12 months after surgery in the two groups was significantly lower than that before surgery, with statistical significance (P<0.05). According to Brisman efficacy evaluation criteria for trigeminal neuralgia, no significant difference was found in the efficacy between the two groups at 1 and 3 months after surgery (P>0.05). At 6 and 12 months postoperatively, the effectiveness of the research group was higher than that of the control group, and the differences were statistically significant (P<0.05). In the research group, no recurrence occurred during the follow-up period, whereas in the control group, one, two, and four recurrences occurred 3, 6, and 12 months after surgery, respectively. No obvious complications were found in both groups. CONCLUSIONS: 3D printed template-guided radiofrequency thermocoagulation combined with doxorubicin injection for the treatment of trigeminal neuralgia mandibular branch could enhance the long-term curative effect and reduce the recurrence rate, thus worthy of clinical promotion and application.

20.
Front Immunol ; 13: 925738, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35874713

RESUMEN

Chronic inflammation contributes to maladaptive kidney repair, but its regulation is unclear. Here, we report that sirtuin 1 (SIRT1) is downregulated after repeated low-dose cisplatin (RLDC) injury, and this downregulation leads to p65 acetylation and consequent NF-κB activation resulting in a persistent inflammatory response. RLDC induced the down-regulation of SIRT1 and activation of NF-κB, which were accompanied by chronic tubular damage, tubulointerstitial inflammation, and fibrosis in mice. Inhibition of NF-κB suppressed the production of pro-inflammatory cytokines and fibrotic phenotypes in RLDC-treated renal tubular cells. SIRT1 activation by its agonists markedly reduced the acetylation of p65 (a key component of NF-κB), resulting in the attenuation of the inflammatory and fibrotic responses. Conversely, knockdown of SIRT1 exacerbated these cellular changes. At the upstream, p53 was activated after RLDC treatment to repress SIRT1, resulting in p65 acetylation, NF-κB activation and transcription of inflammatory cytokines. In mice, SIRT1 agonists attenuated RLDC-induced chronic inflammation, tissue damage, and renal fibrosis. Together, these results unveil the p53/SIRT1/NF-κB signaling axis in maladaptive kidney repair following RLDC treatment, where p53 represses SIRT1 to increase p65 acetylation for NF-κB activation, leading to chronic renal inflammation.


Asunto(s)
FN-kappa B , Sirtuina 1 , Animales , Cisplatino/efectos adversos , Citocinas/metabolismo , Inflamación/tratamiento farmacológico , Riñón/metabolismo , Ratones , FN-kappa B/metabolismo , Sirtuina 1/metabolismo , Proteína p53 Supresora de Tumor/genética
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