Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 911
Filtrar
1.
Nature ; 629(8010): 67-73, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38632409

RESUMEN

It is well established that near-field radiative heat transfer (NFRHT) can exceed Planck's blackbody limit1 by orders of magnitude owing to the tunnelling of evanescent electromagnetic frustrated and surface modes2-4, as has been demonstrated experimentally for NFRHT between two large parallel surfaces5-7 and between two subwavelength membranes8,9. However, although nanostructures can also sustain a much richer variety of localized electromagnetic modes at their corners and edges10,11, the contributions of such additional modes to further enhancing NFRHT remain unexplored. Here we demonstrate both theoretically and experimentally a physical mechanism of NFRHT mediated by the corner and edge modes, and show that it can dominate the NFRHT in the 'dual nanoscale regime' in which both the thickness of the emitter and receiver, and their gap spacing, are much smaller than the thermal photon wavelengths. For two coplanar 20-nm-thick silicon carbide membranes separated by a 100-nm vacuum gap, the NFRHT coefficient at room temperature is both predicted and measured to be 830 W m-2 K-1, which is 5.5 times larger than that for two infinite silicon carbide surfaces separated by the same gap, and 1,400 times larger than the corresponding blackbody limit accounting for the geometric view factor between two coplanar membranes. This enhancement is dominated by the electromagnetic corner and edge modes, which account for 81% of the NFRHT between the silicon carbide membranes. These findings are important for future NFRHT applications in thermal management and energy conversion.

2.
Chem Soc Rev ; 53(10): 4877-4925, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38595056

RESUMEN

Batteries play a pivotal role in various electrochemical energy storage systems, functioning as essential components to enhance energy utilization efficiency and expedite the realization of energy and environmental sustainability. Zn-based batteries have attracted increasing attention as a promising alternative to lithium-ion batteries owing to their cost effectiveness, enhanced intrinsic safety, and favorable electrochemical performance. In this context, substantial endeavors have been dedicated to crafting and advancing high-performance Zn-based batteries. However, some challenges, including limited discharging capacity, low operating voltage, low energy density, short cycle life, and complicated energy storage mechanism, need to be addressed in order to render large-scale practical applications. In this review, we comprehensively present recent advances in designing high-performance Zn-based batteries and in elucidating energy storage mechanisms. First, various redox mechanisms in Zn-based batteries are systematically summarized, including insertion-type, conversion-type, coordination-type, and catalysis-type mechanisms. Subsequently, the design strategies aiming at enhancing the electrochemical performance of Zn-based batteries are underscored, focusing on several aspects, including output voltage, capacity, energy density, and cycle life. Finally, challenges and future prospects of Zn-based batteries are discussed.

3.
J Am Chem Soc ; 146(30): 20857-20867, 2024 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-39025826

RESUMEN

Asymmetric soft-stiff patch nanohybrids with small size, spatially separated organics and inorganics, controllable configuration, and appealing functionality are important in applications, while the synthesis remains a great challenge. Herein, based on polymeric single micelles (the smallest assembly subunit of mesoporous materials), we report a dynamic surface-mediated anisotropic assembly approach to fabricate a new type of small asymmetric organic/inorganic patch nanohybrid for the first time. The size of this asymmetric organic/inorganic nanohybrid is ∼20 nm, which contains dual distinct subunits of a soft organic PS-PVP-PEO single micelle nanosphere (12 nm in size and 632 MPa in Young' modulus) and stiff inorganic SiO2 nanobulge (∼8 nm, 2275 MPa). Moreover, the number of SiO2 nanobulges anchored on each micelle can be quantitatively controlled (from 1 to 6) by dynamically tuning the density (fluffy or dense state) of the surface cap organic groups. This small asymmetric patch nanohybrid also exhibits a dramatically enhanced uptake level of which the total amount of intracellular endocytosis is about three times higher than that of the conventional nanohybrids.

4.
Mol Cancer ; 23(1): 143, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38992675

RESUMEN

BACKGROUND: Emerging evidence indicates the pivotal involvement of circular RNAs (circRNAs) in cancer initiation and progression. Understanding the functions and underlying mechanisms of circRNAs in tumor development holds promise for uncovering novel diagnostic indicators and therapeutic targets. In this study, our focus was to elucidate the function and regulatory mechanism of hsa-circ-0003764 in hepatocellular carcinoma (HCC). METHODS: A newly discovered hsa-circ-0003764 (circPTPN12) was identified from the circbase database. QRT-PCR analysis was utilized to assess the expression levels of hsa-circ-0003764 in both HCC tissues and cells. We conducted in vitro and in vivo experiments to examine the impact of circPTPN12 on the proliferation and apoptosis of HCC cells. Additionally, RNA-sequencing, RNA immunoprecipitation, biotin-coupled probe pull-down assays, and FISH were employed to confirm and establish the relationship between hsa-circ-0003764, PDLIM2, OTUD6B, P65, and ESRP1. RESULTS: In HCC, the downregulation of circPTPN12 was associated with an unfavorable prognosis. CircPTPN12 exhibited suppressive effects on the proliferation of HCC cells both in vitro and in vivo. Mechanistically, RNA sequencing assays unveiled the NF-κB signaling pathway as a targeted pathway of circPTPN12. Functionally, circPTPN12 was found to interact with the PDZ domain of PDLIM2, facilitating the ubiquitination of P65. Furthermore, circPTPN12 bolstered the assembly of the PDLIM2/OTUD6B complex by promoting the deubiquitination of PDLIM2. ESRP1 was identified to bind to pre-PTPN12, thereby fostering the generation of circPTPN12. CONCLUSIONS: Collectively, our findings indicate the involvement of circPTPN12 in modulating PDLIM2 function, influencing HCC progression. The identified ESRP1/circPTPN12/PDLIM2/NF-κB axis shows promise as a novel therapeutic target in the context of HCC.


Asunto(s)
Carcinoma Hepatocelular , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Proteínas con Dominio LIM , Neoplasias Hepáticas , FN-kappa B , ARN Circular , Proteínas de Unión al ARN , Transducción de Señal , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/metabolismo , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/metabolismo , ARN Circular/genética , Proteínas con Dominio LIM/genética , Proteínas con Dominio LIM/metabolismo , FN-kappa B/metabolismo , Ratones , Animales , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética , Línea Celular Tumoral , Progresión de la Enfermedad , Apoptosis/genética , Pronóstico , Proteínas de Microfilamentos/genética , Proteínas de Microfilamentos/metabolismo , Masculino , Femenino , Ratones Desnudos
5.
Chromosoma ; 132(4): 257-268, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37227491

RESUMEN

Transcriptional repressor B cell lymphoma 6 (Bcl6) is a major transcription factor involved in Tfh cell differentiation and germinal center response, which is regulated by a variety of biological processes. However, the functional impact of post-translational modifications, particularly lysine ß-hydroxybutyrylation (Kbhb), on Bcl6 remains elusive. In this study, we revealed that Bcl6 is modified by Kbhb to affect Tfh cell differentiation, resulting in the decrease of cell population and cytokine IL-21. Furthermore, the modification sites are identified from enzymatic reactions to be lysine residues at positions 376, 377, and 379 by mass spectrometry, which is confirmed by site-directed mutagenesis and functional analyses. Collectively, our present study provides evidence on the Kbhb modification of Bcl6 and also generates new insights into the regulation of Tfh cell differentiation, which is a starting point for a thorough understanding of the functional involvement of Kbhb modification in the differentiations of Tfh and other T cells.


Asunto(s)
Proteínas de Unión al ADN , Factores de Transcripción , Proteínas Proto-Oncogénicas c-bcl-6/genética , Lisina , Linfocitos T Colaboradores-Inductores , Diferenciación Celular
6.
Nat Methods ; 18(1): 31, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33408400

RESUMEN

Microfluidic channels provide a means to deliver barcodes encoding spatial information to a tissue, which allows co-profiling of gene expression and proteins of interest in a spatially resolved manner.


Asunto(s)
Perfilación de la Expresión Génica , Expresión Génica , Análisis de Secuencia
7.
Ann Surg Oncol ; 31(2): 774-782, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37993745

RESUMEN

BACKGROUND: Prognosis prediction of patients with gastric cancer after neoadjuvant chemotherapy is suboptimal. This study aims to develop and validate a dynamic radiomic model for prognosis prediction of patients with gastric cancer on the basis of baseline and posttreatment features. PATIENTS AND METHODS: This single-center cohort study included patients with gastric adenocarcinoma treated with neoadjuvant chemotherapy from June 2009 to July 2015 in the Gastrointestinal Cancer Center of Peking University Cancer Hospital. Their clinicopathological data, pre-treatment and post-treatment computed tomography (CT) images, and pathological reports were retrieved and analyzed. Four prediction models were developed and validated using tenfold cross-validation, with death within 3 years as the outcome. Model discrimination was compared by the area under the curve (AUC). The final radiomic model was evaluated for calibration and clinical utility using Hosmer-Lemeshow tests and decision curve analysis. RESULTS: The study included 205 patients with gastric adenocarcinoma [166 (81%) male; mean age 59.9 (SD 10.3) years], with 71 (34.6%) deaths occurring within 3 years. The radiomic model alone demonstrated better discrimination than the pathological T stage (ypT) stage model alone (cross-validated AUC 0.598 versus 0.516, P = 0.009). The final radiomic model, which incorporated both radiomic and clinicopathological characteristics, had a significantly higher cross-validated AUC (0.769) than the ypT stage model (0.516), the radiomics alone model (0.598), and the ypT plus other clinicopathological characteristics model (0.738; all P < 0.05). Decision curve analysis confirmed the clinical utility of the final radiomic model. CONCLUSIONS: The developed radiomic model had good accuracy and could be used as a decision aid tool in clinical practice to differentiate prognosis of patients with gastric cancer.


Asunto(s)
Adenocarcinoma , Neoplasias Gástricas , Humanos , Masculino , Persona de Mediana Edad , Femenino , Terapia Neoadyuvante , Neoplasias Gástricas/diagnóstico por imagen , Neoplasias Gástricas/tratamiento farmacológico , Estudios de Cohortes , Radiómica , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/tratamiento farmacológico , Estudios Retrospectivos , Análisis de Supervivencia
8.
Biomacromolecules ; 25(4): 2542-2553, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38547378

RESUMEN

Negative pressure wound therapy (NPWT) is effective in repairing serious skin injury. The dressing used in the NPWT is important for wound healing. In this paper, we develop biodegradable amphiphilic polyurethanes (PUs) and fabricate the PUs into sponges as wound dressings (Bi@e) with Janus pore architectures for NPWT. The Bi@e is adaptive to all the stages of the wound healing process. The Janus Bi@e sponge consists of two layers: the dense hydrophobic upper layer with small pores provides protection and support during negative pressure drainage, and the loose hydrophilic lower layer with large pores absorbs large amounts of wound exudate and maintains a moist environment. Additionally, antibacterial agent silver sulfadiazine (SSD) is loaded into the sponge against Escherichia coli and Staphylococcus aureus with a concentration of 0.50 wt%. The Janus sponge exhibits a super absorbent capacity of 19.53 times its own water weight and remarkable resistance to compression. In a rat skin defect model, the Janus Bi@e sponge not only prevents the conglutination between regenerative skin and dressing but also accelerates wound healing compared to commercially available NPWT dressing. The Janus Bi@e sponge is a promising dressing for the NPWT.


Asunto(s)
Terapia de Presión Negativa para Heridas , Animales , Ratas , Cicatrización de Heridas , Vendajes , Piel , Supuración
9.
J Org Chem ; 89(10): 7286-7294, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38696309

RESUMEN

Here we report a carbene-catalyzed enantio- and diastereoselective [4+2] cycloaddition reaction of cyclobutenones with isatins for the quick and efficient synthesis of spirocyclic δ-lactones bearing a chiral chlorine. A broad range of substrates with various substitution patterns proceed smoothly in this reaction, with the spirooxindole δ-lactone products afforded in generally good to excellent yields and optical purities under mild reaction conditions.

10.
Phys Chem Chem Phys ; 26(4): 2895-2906, 2024 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-38170851

RESUMEN

Ionic current rectification generated by the geometric asymmetry of conical nanochannels has gradually attracted attention, but most studies have been limited to Newtonian fluids. In this study, the ionic current rectification characteristics in conical nanochannels filled with non-Newtonian fluids are investigated by numerical simulations. Electroosmotic flow and ion transport in Sisko fluids are solved using the Poisson-Nernst-Planck equations and the Navier-Stokes equations. The effects of the Debye parameter, power-law indexes and applied voltage on the ionic current, axial potential, ion concentration, radial velocity and rectification ratio in the nanopores are investigated. When κRt = 1, the current rectification ratio increases with the increase of the power-law index. However, when κRt = 6, the current rectification ratio first increases and then decreases with the increase of the power law index, reaching the maximum value at n = 1.0. These findings have positive implications for the construction of some nanodevices such as nanofluidic diodes.

11.
Bioorg Chem ; 143: 107034, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38118299

RESUMEN

In continuation of our program to search for novel potential anti-ischemic stroke agents, a series of 1,3,4-oxadiazole and sulfoxide hybrids of phthalide derivatives was designed and synthesized in this study to evaluate their anti-ischemic stroke activity. Among them, compounds 5b, 5d, 5 l, and 5 m exhibited excellent inhibitory effects on platelet aggregation induced by adenosine diphosphate (ADP) and arachidonic acid (AA). In particular, compound 5b possessed considerable antithrombotic activity in animal models, as demonstrated by the effective alleviation of carrageenan-induced and FeCl3-induced thrombosis in tail and carotid arteries, respectively. Notably, intraperitoneal administration of compound 5b could better protect the brain from injury caused by ischemia/reperfusion in rats compared with precursor 3-n-butylphthalide. Further pharmacokinetics, liver microsomal stability, and PAMPA-BBB assays also indicated that compound 5b had relatively high bioavailability, metabolic stability, and BBB permeability. Moreover, compound 5b showed a safety profile that was superior to the clinical drugs clopidogrel, aspirin, and 3-n-butylphthalide in the mouse-tail bleeding assay. Finally, molecular docking predicted that the potential target of the antiplatelet aggregation activity of compound 5b was P2Y12 receptor. This research provides a novel candidate compound for the treatment of ischemic stroke.


Asunto(s)
Benzofuranos , Accidente Cerebrovascular Isquémico , Oxadiazoles , Inhibidores de Agregación Plaquetaria , Ratones , Ratas , Animales , Inhibidores de Agregación Plaquetaria/farmacología , Inhibidores de Agregación Plaquetaria/uso terapéutico , Simulación del Acoplamiento Molecular , Accidente Cerebrovascular Isquémico/tratamiento farmacológico
12.
Acta Pharmacol Sin ; 45(3): 502-516, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37880338

RESUMEN

Olanzapine (OLZ) is a widely prescribed antipsychotic drug with a relatively ideal effect in the treatment of schizophrenia (SCZ). However, its severe metabolic side effects often deteriorate clinical therapeutic compliance and mental rehabilitation. The peripheral mechanism of OLZ-induced metabolic disorders remains abstruse for its muti-target activities. Endoplasmic reticulum (ER) stress is implicated in cellular energy metabolism and the progression of psychiatric disorders. In this study, we investigated the role of ER stress in the development of OLZ-induced dyslipidemia. A cohort of 146 SCZ patients receiving OLZ monotherapy was recruited, and blood samples and clinical data were collected at baseline, and in the 4th week, 12th week, and 24th week of the treatment. This case-control study revealed that OLZ treatment significantly elevated serum levels of endoplasmic reticulum (ER) stress markers GRP78, ATF4, and CHOP in SCZ patients with dyslipidemia. In HepG2 cells, treatment with OLZ (25, 50 µM) dose-dependently enhanced hepatic de novo lipogenesis accompanied by SREBPs activation, and simultaneously triggered ER stress. Inhibition of ER stress by tauroursodeoxycholate (TUDCA) and 4-phenyl butyric acid (4-PBA) attenuated OLZ-induced lipid dysregulation in vitro and in vivo. Moreover, we demonstrated that activation of PERK-CHOP signaling during ER stress was a major contributor to OLZ-triggered abnormal lipid metabolism in the liver, suggesting that PERK could be a potential target for ameliorating the development of OLZ-mediated lipid dysfunction. Taken together, ER stress inhibitors could be a potentially effective intervention against OLZ-induced dyslipidemia in SCZ.


Asunto(s)
Dislipidemias , Transducción de Señal , Humanos , Olanzapina/farmacología , Estudios de Casos y Controles , Estrés del Retículo Endoplásmico , Dislipidemias/inducido químicamente , Lípidos , eIF-2 Quinasa/metabolismo , Apoptosis
13.
BMC Pediatr ; 24(1): 82, 2024 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-38279097

RESUMEN

BACKGROUND: Severe neonatal hyperbilirubinemia could lead to kernicterus and neonatal death. This study aimed to analyze the association between single nucleotide polymorphisms in genes involved in bilirubin metabolism and the incidence of severe hyperbilirubinemia. METHODS: A total of 144 neonates with severe hyperbilirubinemia and 50 neonates without or mild hyperbilirubinemia were enrolled in 3 institutions between 2019 and 2020. Twelve polymorphisms of 5 genes (UGT1A1, SLCO1B1, SLCO1B3, BLVRA, and HMOX1) were analyzed by PCR amplification of genomic DNA. Genotyping was performed using an improved multiplex ligation detection reaction technique based on ligase detection reaction. RESULTS: The frequencies of the A allele in UGT1A1-rs4148323 and the C allele in SLCO1B3-rs2417940 in the severe hyperbilirubinemia group (30.2% and 90.6%, respectively) were significantly higher than those in the controls (30.2% vs.13.0%, 90.6% vs. 78.0%, respectively, both p < 0.05). Haplotype analysis showed the ACG haplotype of UGT1A1 were associated with an increased hyperbilirubinemia risk (OR 3.122, p = 0.001), whereas the GCG haplotype was related to a reduced risk (OR 0.523, p = 0.018). CONCLUSION: The frequencies of the A allele in rs4148323 and the C allele in rs2417940 are highly associated with the incidence of severe hyperbilirubinemia in Chinese Han neonates. TRIAL REGISTRATION: Trial registration number:ChiCTR1800020424; Date of registration:2018-12-29.


Asunto(s)
Hiperbilirrubinemia Neonatal , Polimorfismo de Nucleótido Simple , Recién Nacido , Humanos , Transportador 1 de Anión Orgánico Específico del Hígado/genética , Alelos , Hiperbilirrubinemia Neonatal/genética , Glucuronosiltransferasa/genética , China/epidemiología , Miembro 1B3 de la Familia de los Transportadores de Solutos de Aniones Orgánicos/genética , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo
14.
Proc Natl Acad Sci U S A ; 118(4)2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33431650

RESUMEN

The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people ("source control") with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.


Asunto(s)
COVID-19 , Trazado de Contacto , Máscaras , SARS-CoV-2 , COVID-19/epidemiología , COVID-19/prevención & control , Humanos
15.
Chem Biodivers ; 21(3): e202400043, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38361278

RESUMEN

Four series of novel 1,3,4-oxadiazole/1,2,4-triazole hybrids of phthalide derivatives were designed and synthesized to search for novel potential antifungal agents. Preliminary antifungal activity assay results showed that compounds 4 a, 4 b, 4 m, 5 b, 5 f, 5 h, and 7 h exhibited moderate to excellent inhibitory activity against some phytopathogenic fungi. Among them, compound 5 b displayed the most outstanding antifungal effects against V. mali and S. sclerotiorum, with the EC50 mean of 3.96 µg/mL and 5.60 µg/mL, respectively, which was superior to those of commercial fungicides hymexazol and chlorothalonil. Furthermore, compound 5 b could completely suppress the spore germination of V. mali at a concentration of 10 µg/mL. Finally, molecular docking revealed that the potential target for the antifungal activity of compound 5 b was succinate dehydrogenase (SDH). This research provides novel candidate compounds for the prevention of phytopathogenic fungi.


Asunto(s)
Antifúngicos , Benzofuranos , Hongos , Oxadiazoles , Triazoles , Antifúngicos/farmacología , Relación Estructura-Actividad , Simulación del Acoplamiento Molecular
16.
Chem Biodivers ; 21(5): e202400110, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38424689

RESUMEN

Drugs with anti-platelet aggregation and neuroprotection are of great significance for the treatment of ischemic stroke. A series of edaravone and 6-phenyl-4,5-dihydropyridazin-3(2H)-one hybrids were designed and synthesized. Among them, 6g showed the most effective cytoprotective effect against oxygen-glucose deprivation/reoxygenation-induced damage in BV2 cells and an excellent inhibitory effect on platelet aggregation induced by adenosine diphosphate and arachidonic acid. Additionally, 6g could prevent thrombosis caused by ferric chloride in rats and pose a lower risk of causing bleeding compared with aspirin. It provides better protection against ischemia/reperfusion injury in rats compared with edaravone and alleviates the oxidative stress related to cerebral ischemia/reperfusion by increasing the GSH and SOD levels and decreasing the MDA concentration. Finally, molecular docking results showed that 6g probably acts on PDE3 A and plays an anti-platelet aggregation effect. Overall, 6g could be a potential candidate compound for the treatment of ischemic stroke.


Asunto(s)
Edaravona , Accidente Cerebrovascular Isquémico , Fármacos Neuroprotectores , Inhibidores de Agregación Plaquetaria , Agregación Plaquetaria , Animales , Edaravona/farmacología , Edaravona/química , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Accidente Cerebrovascular Isquémico/metabolismo , Accidente Cerebrovascular Isquémico/patología , Ratas , Inhibidores de Agregación Plaquetaria/farmacología , Inhibidores de Agregación Plaquetaria/química , Inhibidores de Agregación Plaquetaria/síntesis química , Agregación Plaquetaria/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/síntesis química , Simulación del Acoplamiento Molecular , Masculino , Ratones , Estructura Molecular , Relación Estructura-Actividad , Ratas Sprague-Dawley , Descubrimiento de Drogas , Piridazinas/farmacología , Piridazinas/química , Estrés Oxidativo/efectos de los fármacos
17.
Bioprocess Biosyst Eng ; 47(3): 355-366, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38326513

RESUMEN

Dyes in wastewater have adverse effects on the environment and human health. Dye-decolorizing peroxidase (DyP) is a promising biocatalyst to dyes degradation, but the decolorization rates varied greatly which influencing factors and mechanisms remain to be fully disclosed. To explore an effective decolorizing approach, we have studied a DyP from Rhodococcus jostii (RhDyPB) which was overexpressed in Escherichia coli to decolorize four kinds of dyes, Reactive blue 19, Eosin Y, Indigo carmine, and Malachite green. We found the decolorization rates of the dyes by purified RhDyPB were all pH-dependent and the highest one was 94.4% of Malachite green at pH 6.0. ESI-MS analysis of intermediates in the decolorization process of Reactive blue 19 proved the degradation was due to peroxidase catalysis. Molecular docking predicated the interaction of RhDyPB with dyes, and a radical transfer reaction. In addition, we performed decolorization of dyes with whole E. coli cell with and without expressing RhDyPB. It was found that decolorization of dyes by E. coli cell was due to both cell absorption and degradation, and RhDyPB expression improved the degradation rates towards Reactive blue 19, Indigo carmine and Malachite green. The effective decolorization of Malachite green and the successful application of whole DyP-overexpressed cells in dye decolorization is conducive to the bioremediation of dye-containing wastewaters by DyPs.


Asunto(s)
Antraquinonas , Colorantes , Peroxidasa , Rhodococcus , Colorantes de Rosanilina , Humanos , Colorantes/química , Carmin de Índigo , Escherichia coli/genética , Escherichia coli/metabolismo , Simulación del Acoplamiento Molecular , Peroxidasas/química , Oxidorreductasas , Aguas Residuales , Biodegradación Ambiental , Catálisis , Concentración de Iones de Hidrógeno
18.
J Asian Nat Prod Res ; 26(8): 900-909, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38753580

RESUMEN

Nine jatrophane diterpenoids were isolated from the whole plant Euphorbia helioscopia, including two new ones, helioscopnins A (1) and B (2). Comprehensive spectroscopic data analysis and ECD calculations elucidated their structures, including absolute configurations. All compounds were evaluated for bioactivity towards autophagic flux by flow cytometry using HM mCherry-GFP-LC3 cells. Compounds 1, 3, 4, 5, 8, and 9 significantly increased autophagic flux.


Asunto(s)
Autofagia , Diterpenos , Euphorbia , Euphorbia/química , Diterpenos/farmacología , Diterpenos/química , Diterpenos/aislamiento & purificación , Autofagia/efectos de los fármacos , Estructura Molecular , Humanos
19.
Angew Chem Int Ed Engl ; 63(29): e202405222, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38729920

RESUMEN

The exploration of the complex chemical diversity of bicyclo[n.1.1]alkanes and their use as benzene bioisosteres has garnered significant attention over the past two decades. Regiodivergent syntheses of thiabicyclo[4.1.1]octanes (S-BCOs) and highly substituted bicyclo[2.1.1]hexanes (BCHs) using a Lewis acid-catalyzed formal cycloaddition of bicyclobutanes (BCBs) and 3-benzylideneindoline-2-thione derivatives have been established. The first hetero-(4+3) cycloaddition of BCBs, catalyzed by Zn(OTf)2, was achieved with a broad substrate scope under mild conditions. In contrast, the less electrophilic BCB ester undergoes a Sc(OTf)3-catalyzed [2π+2σ] reaction with 1,1,2-trisubstituted alkenes, yielding BCHs with a spirocyclic quaternary carbon center. Control experiments and preliminary theoretical calculations suggest that the diastereoselective [2π+2σ] product formation may involve a concerted cycloaddition between a zwitterionic intermediate and E-1,1,2-trisubstituted alkenes. Additionally, the hetero-(4+3) cycloaddition may involve a concerted nucleophilic ring-opening mechanism.

20.
Angew Chem Int Ed Engl ; : e202408578, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38818620

RESUMEN

Bridged cyclobutanes and sulfur heterocycles are currently under intense investigation as building blocks for pharmaceutical drug design. Two formal cycloaddition modes involving bicyclobutanes (BCBs) and pyridinium 1,4-zwitterionic thiolate derivatives were described to rapidly expand the chemical space of sulfur-containing bridged cyclobutanes. By using Ni(ClO4)2 as the catalyst, an uncommon higher-order (5+3) cycloaddition of BCBs with quinolinium 1,4-zwitterionic thiolate was achieved with broad substrate scope under mild reaction conditions. Furthermore, the first Lewis acid-catalyzed asymmetric polar (5+3) cycloaddition of BCB with pyridazinium 1,4-zwitterionic thiolate was accomplished. In contrast, pyridinium 1,4-zwitterionic thiolates undergo an Sc(OTf)3-catalyzed formal (3+3) reaction with BCBs to generate thia-norpinene products, which represent the initial instance of synthesizing 2-thiabicyclo[3.1.1]heptanes (thia-BCHeps) from BCBs. Moreover, we have successfully used this (3+3) protocol to rapidly prepare thia-BCHeps-substituted analogues of the bioactive molecule Pitofenone. Density functional theory (DFT) computations imply that kinetic factors govern the (5+3) cycloaddition reaction between BCB and quinolinium 1,4-zwitterionic thiolate, whereas the (3+3) reaction involving pyridinium 1,4-zwitterionic thiolates is under thermodynamic control.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA