Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 349
Filtrar
Más filtros

País/Región como asunto
Intervalo de año de publicación
1.
Genes Dev ; 38(13-14): 675-691, 2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39137945

RESUMEN

Tumor suppressor genes play critical roles in normal tissue homeostasis, and their dysregulation underlies human diseases including cancer. Besides human genetics, model organisms such as Drosophila have been instrumental in discovering tumor suppressor pathways that were subsequently shown to be highly relevant in human cancer. Here we show that hyperplastic disc (Hyd), one of the first tumor suppressors isolated genetically in Drosophila and encoding an E3 ubiquitin ligase with hitherto unknown substrates, and Lines (Lin), best known for its role in embryonic segmentation, define an obligatory tumor suppressor protein complex (Hyd-Lin) that targets the zinc finger-containing oncoprotein Bowl for ubiquitin-mediated degradation, with Lin functioning as a substrate adaptor to recruit Bowl to Hyd for ubiquitination. Interestingly, the activity of the Hyd-Lin complex is directly inhibited by a micropeptide encoded by another zinc finger gene, drumstick (drm), which functions as a pseudosubstrate by displacing Bowl from the Hyd-Lin complex, thus stabilizing Bowl. We further identify the epigenetic regulator Polycomb repressive complex1 (PRC1) as a critical upstream regulator of the Hyd-Lin-Bowl pathway by directly repressing the transcription of the micropeptide drm Consistent with these molecular studies, we show that genetic inactivation of Hyd, Lin, or PRC1 resulted in Bowl-dependent hyperplastic tissue overgrowth in vivo. We also provide evidence that the mammalian homologs of Hyd (UBR5, known to be recurrently dysregulated in various human cancers), Lin (LINS1), and Bowl (OSR1/2) constitute an analogous protein degradation pathway in human cells, and that OSR2 promotes prostate cancer tumorigenesis. Altogether, these findings define a previously unrecognized tumor suppressor pathway that links epigenetic program to regulated protein degradation in tissue growth control and tumorigenesis.


Asunto(s)
Carcinogénesis , Proteínas de Drosophila , Proteolisis , Ubiquitina-Proteína Ligasas , Animales , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina-Proteína Ligasas/genética , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Carcinogénesis/genética , Humanos , Proteínas Supresoras de Tumor/metabolismo , Proteínas Supresoras de Tumor/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Drosophila melanogaster/embriología , Genes Supresores de Tumor , Ubiquitinación , Proteínas del Grupo Polycomb/metabolismo , Proteínas del Grupo Polycomb/genética , Complejo Represivo Polycomb 1/metabolismo , Complejo Represivo Polycomb 1/genética
2.
Mol Cell ; 83(20): 3578-3581, 2023 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-37863024

RESUMEN

Molecular Cell talks to co-first authors Meiling Wang and Wenjing Li with co-corresponding author Weixing Zhao about their paper, "Crucial roles of the BRCA1-BARD1 E3 ubiquitin ligase activity in homology-directed DNA repair" (in this issue of Molecular Cell) and what motivates their scientific pursuits.


Asunto(s)
Proteínas Supresoras de Tumor , Ubiquitina-Proteína Ligasas , Proteínas Supresoras de Tumor/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación
3.
Mol Cell ; 83(20): 3679-3691.e8, 2023 10 19.
Artículo en Inglés | MEDLINE | ID: mdl-37797621

RESUMEN

The tumor-suppressor breast cancer 1 (BRCA1) in complex with BRCA1-associated really interesting new gene (RING) domain 1 (BARD1) is a RING-type ubiquitin E3 ligase that modifies nucleosomal histone and other substrates. The importance of BRCA1-BARD1 E3 activity in tumor suppression remains highly controversial, mainly stemming from studying mutant ligase-deficient BRCA1-BARD1 species that we show here still retain significant ligase activity. Using full-length BRCA1-BARD1, we establish robust BRCA1-BARD1-mediated ubiquitylation with specificity, uncover multiple modes of activity modulation, and construct a truly ligase-null variant and a variant specifically impaired in targeting nucleosomal histones. Cells expressing either of these BRCA1-BARD1 separation-of-function alleles are hypersensitive to DNA-damaging agents. Furthermore, we demonstrate that BRCA1-BARD1 ligase is not only required for DNA resection during homology-directed repair (HDR) but also contributes to later stages for HDR completion. Altogether, our findings reveal crucial, previously unrecognized roles of BRCA1-BARD1 ligase activity in genome repair via HDR, settle prior controversies regarding BRCA1-BARD1 ligase functions, and catalyze new efforts to uncover substrates related to tumor suppression.


Asunto(s)
Neoplasias , Proteínas Supresoras de Tumor , Humanos , Proteínas Supresoras de Tumor/metabolismo , Proteína BRCA1/metabolismo , Ubiquitinación , Histonas/genética , Histonas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Reparación del ADN por Recombinación , ADN , Reparación del ADN
4.
EMBO J ; 42(15): e113565, 2023 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-37305927

RESUMEN

BRCA1/BARD1 is a tumor suppressor E3 ubiquitin (Ub) ligase with roles in DNA damage repair and in transcriptional regulation. BRCA1/BARD1 RING domains interact with nucleosomes to facilitate mono-ubiquitylation of distinct residues on the C-terminal tail of histone H2A. These enzymatic domains constitute a small fraction of the heterodimer, raising the possibility of functional chromatin interactions involving other regions such as the BARD1 C-terminal domains that bind nucleosomes containing the DNA damage signal H2A K15-Ub and H4 K20me0, or portions of the expansive intrinsically disordered regions found in both subunits. Herein, we reveal novel interactions that support robust H2A ubiquitylation activity mediated through a high-affinity, intrinsically disordered DNA-binding region of BARD1. These interactions support BRCA1/BARD1 recruitment to chromatin and sites of DNA damage in cells and contribute to their survival. We also reveal distinct BRCA1/BARD1 complexes that depend on the presence of H2A K15-Ub, including a complex where a single BARD1 subunit spans adjacent nucleosome units. Our findings identify an extensive network of multivalent BARD1-nucleosome interactions that serve as a platform for BRCA1/BARD1-associated functions on chromatin.


Asunto(s)
Nucleosomas , Proteínas Supresoras de Tumor , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Ubiquitinación , Histonas/genética , Histonas/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Cromatina
5.
Proc Natl Acad Sci U S A ; 120(38): e2310163120, 2023 09 19.
Artículo en Inglés | MEDLINE | ID: mdl-37703282

RESUMEN

Callus is a reprogrammed cell mass involved in plant regeneration and gene transformation in crop engineering. Pluripotent callus cells develop into fertile shoots through shoot regeneration. The molecular basis of the shoot regeneration process in crop callus remains largely elusive. This study pioneers the exploration of the spatial transcriptome of tomato callus during shoot regeneration. The findings reveal the presence of highly heterogeneous cell populations within the callus, including epidermis, vascular tissue, shoot primordia, inner callus, and outgrowth shoots. By characterizing the spatially resolved molecular features of shoot primordia and surrounding cells, specific factors essential for shoot primordia formation are identified. Notably, chlorenchyma cells, enriched in photosynthesis-related processes, play a crucial role in promoting shoot primordia formation and subsequent shoot regeneration. Light is shown to promote shoot regeneration by inducing chlorenchyma cell development and coordinating sugar signaling. These findings significantly advance our understanding of the cellular and molecular aspects of shoot regeneration in tomato callus and demonstrate the immense potential of spatial transcriptomics in plant biology.


Asunto(s)
Solanum lycopersicum , Solanum lycopersicum/genética , Transcriptoma , Células Epiteliales , Perfilación de la Expresión Génica , Regeneración/genética
6.
Brief Bioinform ; 24(6)2023 09 22.
Artículo en Inglés | MEDLINE | ID: mdl-37779250

RESUMEN

The microbiota-gut-brain axis denotes a two-way system of interactions between the gut and the brain, comprising three key components: (1) gut microbiota, (2) intermediates and (3) mental ailments. These constituents communicate with one another to induce changes in the host's mood, cognition and demeanor. Knowledge concerning the regulation of the host central nervous system by gut microbiota is fragmented and mostly confined to disorganized or semi-structured unrestricted texts. Such a format hinders the exploration and comprehension of unknown territories or the further advancement of artificial intelligence systems. Hence, we collated crucial information by scrutinizing an extensive body of literature, amalgamated the extant knowledge of the microbiota-gut-brain axis and depicted it in the form of a knowledge graph named MMiKG, which can be visualized on the GraphXR platform and the Neo4j database, correspondingly. By merging various associated resources and deducing prospective connections between gut microbiota and the central nervous system through MMiKG, users can acquire a more comprehensive perception of the pathogenesis of mental disorders and generate novel insights for advancing therapeutic measures. As a free and open-source platform, MMiKG can be accessed at http://yangbiolab.cn:8501/ with no login requirement.


Asunto(s)
Trastornos Mentales , Microbiota , Humanos , Inteligencia Artificial , Reconocimiento de Normas Patrones Automatizadas , Estudios Prospectivos , Encéfalo
7.
Plant Physiol ; 194(4): 2449-2471, 2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38206196

RESUMEN

Bud dormancy is a crucial strategy for perennial plants to withstand adverse winter conditions. However, the regulatory mechanism of bud dormancy in tree peony (Paeonia suffruticosa) remains largely unknown. Here, we observed dramatically reduced and increased accumulation of abscisic acid (ABA) and bioactive gibberellins (GAs) GA1 and GA3, respectively, during bud endodormancy release of tree peony under prolonged chilling treatment. An Illumina RNA sequencing study was performed to identify potential genes involved in the bud endodormancy regulation in tree peony. Correlation matrix, principal component, and interaction network analyses identified a downregulated MYB transcription factor gene, PsMYB306, the expression of which positively correlated with 9-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (PsNCED3) expression. Protein modeling analysis revealed 4 residues within the R2R3 domain of PsMYB306 to possess DNA binding capability. Transcription of PsMYB306 was increased by ABA treatment. Overexpression of PsMYB306 in petunia (Petunia hybrida) inhibited seed germination and plant growth, concomitant with elevated ABA and decreased GA contents. Silencing of PsMYB306 accelerated cold-triggered tree peony bud burst and influenced the production of ABA and GAs and the expression of their biosynthetic genes. ABA application reduced bud dormancy release and transcription of ENT-KAURENOIC ACID OXIDASE 1 (PsKAO1), GA20-OXIDASE 1 (PsGA20ox1), and GA3-OXIDASE 1 (PsGA3ox1) associated with GA biosynthesis in PsMYB306-silenced buds. In vivo and in vitro binding assays confirmed that PsMYB306 specifically transactivated the promoter of PsNCED3. Silencing of PsNCED3 also promoted bud break and growth. Altogether, our findings suggest that PsMYB306 negatively modulates cold-induced bud endodormancy release by regulating ABA production.


Asunto(s)
Ácido Abscísico , Paeonia , Ácido Abscísico/farmacología , Ácido Abscísico/metabolismo , Paeonia/genética , Paeonia/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Latencia en las Plantas/genética , Regulación de la Expresión Génica de las Plantas , Oxidorreductasas/metabolismo
8.
J Am Chem Soc ; 2024 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-39298380

RESUMEN

Electrosynthesis of multicarbon products, such as C2H4, from CO2 reduction on copper (Cu) catalysts holds promise for achieving carbon neutrality. However, maintaining a steady high current-level C2H4 electrosynthesis still encounters challenges, arising from unstable alkalinity and carbonate precipitation caused by undesired ion migration at the cathode under a repulsive electric field. To address these issues, we propose a universal "charge release" concept by incorporating tiny amounts of an oppositely charged anionic ionomer (e.g., perfluorinated sulfonic acid, PFSA) into a cationic covalent organic framework on the Cu surface (cCOF/PFSA). This strategy effectively releases the hidden positive charge within the cCOF, enhancing surface immobilization of cations to impede both outward migration of generated OH- and inward migration of cations, inhibiting carbonate precipitation and creating a strong alkaline microenvironment. Meanwhile, the ionomer's hydrophobic chains create a hydrophobic environment within the cCOF, facilitating efficient gas transport. In situ characterizations and theoretical calculations demonstrate that the cCOF/PFSA catalyst establishes a hydrophobic strong alkaline microenvironment, optimizing the adsorption strength and configuration of *CO intermediates to promote the C2H4 formation. The optimized catalyst achieves a 70.5% Faradaic efficiency for C2H4 with a partial current density over 470 mA cm-2. Notably, it delivers a high single-pass carbon efficiency of 96.5% for CO2RR and sustains an exceptional stability over 760 h. When implemented in a large-area MEA electrolyzer and a 5-cell MEA stack, the system achieves an industrial current of 15 A and continuous C2H4 production exceeding 19 mL min-1, marking a significant step toward industrial feasibility in CO2RR-to-C2H4 conversion.

9.
Development ; 148(10)2021 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-33999995

RESUMEN

The focal adhesion protein Kindlin2 is essential for integrin activation, a process that is fundamental to cell-extracellular matrix adhesion. Kindlin 2 (Fermt2) is widely expressed in mouse embryos, and its absence causes lethality at the peri-implantation stage due to the failure to trigger integrin activation. The function of kindlin2 during embryogenesis has not yet been fully elucidated as a result of this early embryonic lethality. Here, we showed that kindlin2 is essential for neural crest (NC) formation in Xenopus embryos. Loss-of-function assays performed with kindlin2-specific morpholino antisense oligos (MOs) or with CRISPR/Cas9 techniques in Xenopus embryos severely inhibit the specification of the NC. Moreover, integrin-binding-deficient mutants of Kindlin2 rescued the phenotype caused by loss of kindlin2, suggesting that the function of kindlin2 during NC specification is independent of integrins. Mechanistically, we found that Kindlin2 regulates the fibroblast growth factor (FGF) pathway, and promotes the stability of FGF receptor 1. Our study reveals a novel function of Kindlin2 in regulating the FGF signaling pathway and provides mechanistic insights into the function of Kindlin2 during NC specification.


Asunto(s)
Factores de Crecimiento de Fibroblastos/metabolismo , Proteínas de la Membrana/metabolismo , Cresta Neural/embriología , Proteínas de Xenopus/metabolismo , Xenopus laevis/embriología , Animales , Sistemas CRISPR-Cas/genética , Línea Celular , Embrión no Mamífero/metabolismo , Desarrollo Embrionario/genética , Desarrollo Embrionario/fisiología , Regulación del Desarrollo de la Expresión Génica/genética , Técnicas de Inactivación de Genes , Células HEK293 , Células HeLa , Humanos , Integrinas/metabolismo , Proteínas de la Membrana/genética , Morfolinos/genética , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/metabolismo , Transducción de Señal/genética , Proteínas de Xenopus/genética
10.
BMC Med ; 22(1): 28, 2024 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-38263021

RESUMEN

BACKGROUND: Current hypertension guidelines recommend combination of an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker with a calcium-channel blocker or thiazide diuretic as initial antihypertensive therapy in patients with monotherapy uncontrolled hypertension. However, to what extent these two different combinations are comparable in blood pressure (BP)-lowering efficacy and safety remains under investigation, especially in the Chinese population. We investigated the BP-lowering efficacy and safety of the amlodipine/benazepril and benazepril/hydrochlorothiazide dual therapies in Chinese patients. METHODS: In a multi-center, randomized, actively controlled, parallel-group trial, we enrolled patients with stage 1 or 2 hypertension from July 2018 to June 2021 in 20 hospitals and community health centers across China. Of the 894 screened patients, 560 eligible patients were randomly assigned to amlodipine/benazepril 5/10 mg (n = 282) or benazepril/hydrochlorothiazide 10/12.5 mg (n = 278), with 213 and 212 patients, respectively, who completed the study and had a valid repeat ambulatory BP recording during follow-up and were included in the efficacy analysis. The primary outcome was the change from baseline to 24 weeks of treatment in 24-h ambulatory systolic BP. Adverse events including symptoms and clinically significant changes in physical examinations and laboratory findings were recorded for safety analysis. RESULTS: In the efficacy analysis (n = 425), the primary outcome, 24-h ambulatory systolic BP reduction, was - 13.8 ± 1.2 mmHg in the amlodipine/benazepril group and - 12.3 ± 1.2 mmHg in the benazepril/hydrochlorothiazide group, with a between-group difference of - 1.51 (p = 0.36) mmHg. The between-group differences for major secondary outcomes were - 1.47 (p = 0.18) in 24-h diastolic BP, - 2.86 (p = 0.13) and - 2.74 (p = 0.03) in daytime systolic and diastolic BP, and - 0.45 (p = 0.82) and - 0.93 (p = 0.44) in nighttime systolic and diastolic BP. In the safety analysis (n = 560), the incidence rate of dry cough was significantly lower in the amlodipine/benazepril group than in the benazepril/hydrochlorothiazide group (5.3% vs 10.1%, p = 0.04). CONCLUSIONS: The amlodipine/benazepril and benazepril/hydrochlorothiazide dual therapies were comparable in ambulatory systolic BP lowering. The former combination, compared with the latter, had a greater BP-lowering effect in the daytime and a lower incidence rate of dry cough. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03682692. Registered on 18 September 2018.


Asunto(s)
Hipertensión , Hipotensión , Humanos , Antihipertensivos , Amlodipino , Hidroclorotiazida , China , Tos
11.
Nanotechnology ; 35(44)2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39111327

RESUMEN

In this work, N-doped and oxygen vacancy-rich NiCo2O4/NiO/Co3O4composites are synthesized by the direct calcination method. Noticeably, by changing the additive concentrations of urea dissolved in DMF (N-N dimethylformamide), the electromagnetic wave (EMW) absorption abilities of NiCo2O4/NiO/Co3O4composite effectively. A maximum reflection loss (RLmax) value at 12.94 GHz for a 2.8 mm thick sheet is -29.76 dB, while its effective absorption bandwidth (RL < -10 dB) reaches 4.21 GHz. In-depth research of possible mechanisms of EMW absorption enhancement. Owing to its simple preparation method and superb EMW absorption properties, the NiCo2O4/NiO/Co3O4composites have a chance to be suitable candidates for high-property EMW absorbers.

12.
Am J Otolaryngol ; 45(4): 104342, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38703609

RESUMEN

OBJECTIVE: To develop a multi-instance learning (MIL) based artificial intelligence (AI)-assisted diagnosis models by using laryngoscopic images to differentiate benign and malignant vocal fold leukoplakia (VFL). METHODS: The AI system was developed, trained and validated on 5362 images of 551 patients from three hospitals. Automated regions of interest (ROI) segmentation algorithm was utilized to construct image-level features. MIL was used to fusion image level results to patient level features, then the extracted features were modeled by seven machine learning algorithms. Finally, we evaluated the image level and patient level results. Additionally, 50 videos of VFL were prospectively gathered to assess the system's real-time diagnostic capabilities. A human-machine comparison database was also constructed to compare the diagnostic performance of otolaryngologists with and without AI assistance. RESULTS: In internal and external validation sets, the maximum area under the curve (AUC) for image level segmentation models was 0.775 (95 % CI 0.740-0.811) and 0.720 (95 % CI 0.684-0.756), respectively. Utilizing a MIL-based fusion strategy, the AUC at the patient level increased to 0.869 (95 % CI 0.798-0.940) and 0.851 (95 % CI 0.756-0.945). For real-time video diagnosis, the maximum AUC at the patient level reached 0.850 (95 % CI, 0.743-0.957). With AI assistance, the AUC improved from 0.720 (95 % CI 0.682-0.755) to 0.808 (95 % CI 0.775-0.839) for senior otolaryngologists and from 0.647 (95 % CI 0.608-0.686) to 0.807 (95 % CI 0.773-0.837) for junior otolaryngologists. CONCLUSIONS: The MIL based AI-assisted diagnosis system can significantly improve the diagnostic performance of otolaryngologists for VFL and help to make proper clinical decisions.


Asunto(s)
Inteligencia Artificial , Laringoscopía , Leucoplasia , Pliegues Vocales , Humanos , Pliegues Vocales/diagnóstico por imagen , Pliegues Vocales/patología , Laringoscopía/métodos , Masculino , Leucoplasia/diagnóstico , Leucoplasia/patología , Femenino , Persona de Mediana Edad , Anciano , Diagnóstico por Computador/métodos , Aprendizaje Automático , Diagnóstico Diferencial , Adulto , Algoritmos , Neoplasias Laríngeas/diagnóstico , Neoplasias Laríngeas/patología , Neoplasias Laríngeas/diagnóstico por imagen
13.
Heart Surg Forum ; 27(1): E048-E057, 2024 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-38286640

RESUMEN

OBJECTIVE: To explore the application effect of phase Ⅰ cardiac rehabilitation (CR-Ⅰ) combined with cognitive behavioural therapy (CBT) on patients after aortic valve replacement (AVR). METHODS: This study retrospectively analysed the data of 441 patients after AVR in our hospital from January 2020 to May 2023. A total of 38 patients who did not meet the inclusion criteria were excluded. A total of 403 patients were included. In accordance with different postoperative management schemes, the included patients were divided into the reference group (n = 202, received CR-Ⅰ) and the observation group (n = 201, received CR-Ⅰ+CBT). The cardiac function, exercise capacity and mental health of the two groups were compared. RESULTS: Before management, both groups had no significant differences in left ventricular end diastolic diameter (LVEDD), left ventricular end systolic dimension (LVESD), left ventricular ejection fraction (LVEF) and six-minute walking test (6MWT) scores (p > 0.05). At discharge and 3 months after discharge, the observation group had significantly lower LVEDD and LVESD and remarkably higher LVEF and 6MWT scores than the reference group (p < 0.001). The proportions of autonomous activity in bed within 3-4 days after surgery, autonomous out-of-bed activity within 8-10 days after surgery and autonomous walking 200 m within 12-15 days after surgery were distinctly higher (p < 0.001) and the incidence of adverse reactions was overtly lower (p < 0.001) in the observation group than in the reference group. Before management, both groups had no significant difference in their scores on the State-Trait Anxiety Inventory (STAI) (p > 0.05). At discharge and 3 months after discharge, the observation group had lower STAI scores than the reference group (p < 0.001). CONCLUSION: CR-Ⅰ combined with CBT effectively improves the cardiac function, independent exercise capacity and mental health level of patients after AVR and provides a new direction for the formulation and selection of follow-up clinical management.


Asunto(s)
Rehabilitación Cardiaca , Implantación de Prótesis de Válvulas Cardíacas , Humanos , Válvula Aórtica/cirugía , Estudios Retrospectivos , Volumen Sistólico , Función Ventricular Izquierda , Tolerancia al Ejercicio , Salud Mental , Implantación de Prótesis de Válvulas Cardíacas/métodos , Resultado del Tratamiento
14.
Nano Lett ; 23(1): 336-343, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36546719

RESUMEN

Li and Zn metal batteries are the most promising candidates to replace conventional Li-ion batteries. However, a series of issues, especially dendrites caused by uneven deposition of cations during charge-discharge cycles, hinder their practical application. Here, we proposed a facile separator modification method which combines physical and chemical forces to regulate uniform and rapid deposition of both Li+ and Zn2+. Physically, the electronegativity of modified separators drives rapid transport of metal ions via a surface diffusion mode. Chemically, the polar surface functional groups on coated separators induce uniform deposition of metal ions so that the dendrite growth is effectively inhibited. As a result, the Li and Zn metal anodes employing modified separators can cycle stably for over 1000 h under a large current density of 10 mA cm-2.

15.
Nano Lett ; 23(16): 7411-7418, 2023 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-37530698

RESUMEN

Defective two-dimensional transition metal dichalcogenides can be effective electrocatalysts for Li-S batteries, but the relationship between defect types and battery performance is unclear. In this work, we designed S vacancy-type SV-VS2 and V self-intercalated-type VI-VS2 and measured their catalytic activities in Li-S batteries. Compared with self-intercalating V atoms, S vacancies accelerated Li+ diffusion and SV-VS2 as a Li+ "reservoir" promoted the sulfur conversion kinetics significantly. In addition, the presence of sulfur vacancies promoted the lithiation behavior of SV-VS2 during discharge, leading to an enhancement of the catalytic ability of SV-VS2. However, this lithiation phenomenon weakened the catalytic activity of VI-VS2. Overall, SV-VS2 had better adsorption and catalytic activity. Li-S batteries with SV-VS2-coated separators delivered high rate performance and excellent cycling stability, with a capacity decay rate of 0.043% over 880 cycles at 1.0 C. This work provides an effective strategy for designing efficient Li-S battery electrocatalysts using defect engineering.

16.
Nano Lett ; 23(1): 42-50, 2023 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-36562792

RESUMEN

Dendrite growth and side reactions of Zn metal anodes remain unresolved obstacles for practical application of aqueous Zn ion batteries. Herein, a two-dimensional (2D) organic-inorganic heterostructure with controlled thickness was constructed as a protective layer for a Zn metal anode. The reduction of uniformly distributed polyoxometalate in the layer causes a negative charge density gradient, which can accelerate zinc ion transfer, homogenize zinc deposition, and shield sulfates at the electrode interface, while the exposed hydrophobic alkyl chain of the layer can isolate the direct contact of water with the Zn anode. As a result of the synergetic effect, this 2D organic-inorganic heterostructure enables high Zn plating/stripping reversibility, with high average Coulombic efficiencies of 99.97% for 3700 cycles at 2 mA cm-2. Under high Zn utilization conditions, a high areal-capacity full cell with hundreds of cycles was demonstrated.


Asunto(s)
Metales , Zinc , Suministros de Energía Eléctrica , Electrodos , Agua
17.
Int J Mol Sci ; 25(15)2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39126052

RESUMEN

Exopolysaccharides (EPSs) are carbohydrate polymers that are synthesized and secreted into the extracellular during the growth of microorganisms. Bacillus thuringiensis (Bt) is a type of entomopathogenic bacterium, that produces various insecticidal proteins and EPSs. In our previous study, the EPSs produced by Bt strains were first found to enhance the toxicity of insecticidal crystal proteins against Plutella xylostella. However, the response of the intestinal bacterial communities of P. xylostella under the action of EPSs is still unelucidated. In this study, 16S rRNA amplicon sequencing was used to characterize the intestinal bacterial communities in P. xylostella treated with EPSs alone, Cry1Ac protoxin alone, and both the Cry1Ac protoxin and EPSs. Compared with the control group, alpha diversity indices, the Chao1 and ACE indices were significantly altered after treatment with EPSs alone, and no significant difference was observed between the groups treated with Cry1Ac protoxin alone and Cry1Ac protoxin + EPSs. However, compared with the gut bacterial community feeding on Cry1Ac protoxin alone, the relative abundance of 31 genera was significantly changed in the group treated with Cry1Ac protoxin and EPSs. The intestinal bacteria, through the oral of Cry1Ac protoxin and EPSs, significantly enhanced the toxicity of the Cry1Ac protoxin towards the axenic P. xylostella. In addition, the relative abundance of the 16S rRNA gene in the chloroplasts of Brassica campestris decreased after adding EPSs. Taken together, these results show the vital contribution of the gut microbiota to the Bt strain-killing activity, providing new insights into the mechanism of the synergistic insecticidal activity of Bt proteins and EPSs.


Asunto(s)
Toxinas de Bacillus thuringiensis , Proteínas Bacterianas , Endotoxinas , Microbioma Gastrointestinal , Proteínas Hemolisinas , Mariposas Nocturnas , Animales , Microbioma Gastrointestinal/efectos de los fármacos , Endotoxinas/genética , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/farmacología , Mariposas Nocturnas/efectos de los fármacos , Mariposas Nocturnas/crecimiento & desarrollo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , ARN Ribosómico 16S/genética , Bacillus thuringiensis/genética , Insecticidas/farmacología
18.
J Am Chem Soc ; 145(20): 11323-11332, 2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37166387

RESUMEN

Copper (Cu) is the only known material that can efficiently electrocatalyze CO2 to value-added multicarbon products. Owing to the instability of the Cuδ+ state and microscopic structure in reactions, Cu catalysts are still facing big challenges with low selectivity and poor durability, particularly at high current densities. Herein, we report a rational one-step surface coordination approach for the synthesis of Cu dendrites with an ultrastable Cuδ+ state and hydrophobicity (Cu CF), even after exposure to air for over 6 months. As a result, Cu CF exhibited a C2 FE of 90.6% at a partial current density of 453.3 mA cm-2 in a flow cell. A 400 h stable electrolysis at 800 mA and even a ground-breaking stable operation at a large industrial current of 10 A were achieved in the membrane electrode assembly (MEA) form. We further demonstrated a continuous production of C2H5OH solution with 90% relative purity at 600 mA over 50 h in a solid-electrolyte reactor. Spectroscopy and computation results suggested that Cu(II) carboxylate coordination species formed on the surface of Cu CF, which ensured the stability of the Cuδ+ state and hydrophobicity. As a result, rich active sites and a stable three-phase interface on the catalyst surface were achieved, along with the optimized *CO adsorption strength and adsorption configuration. The mixed *CO adsorption configurations on Cu CF made the *CO dimerization process easier, which promoted the conversion of CO2 to C2 products. This work provides a promising paradigm for the design and development of Cu-based catalysts with ultrahigh stability under industrial current densities.

19.
Small ; 19(30): e2300633, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37035986

RESUMEN

The dendrite growth and side reactions of zinc metal anode in mildly acidic electrolytes seriously hinder the practical application of aqueous zinc-ion battery. To address these issues, an artificial protective layer of nitrogen-doped MXene (NMX) is used to protect the zinc anode. The NMX protective layer has high conductivity and uniformly distributed zincophilic sites, which can not only homogenize the local electric field on the electrode interface but also accelerate the kinetics for Zn deposition. As a result, the NMX protective layer induces uniform zinc deposition and reduces the overpotential of the electrode. Encouragingly, this NMX-protected Zn anode can cycle stably for 1900 h at 1 mA cm-2 and 1 mAh cm-2 . In asymmetric cells, it achieves high cycle reversibility with an average Coulomb efficiency of 99.79% for 4800 cycles at 5 mA cm-2 .

20.
Small ; 19(29): e2302105, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37189230

RESUMEN

The practical applications of aqueous zinc ion batteries are hindered by the formation of dendrites on the anode, the narrow electrochemical window of electrolyte, and the instability of the cathode. To address all these challenges simultaneously, a multi-functional electrolyte additive of 1-phenylethylamine hydrochloride (PEA) is developed for aqueous zinc ion batteries based on polyaniline (PANI) cathode. Experiments and theoretical calculations confirm that the PEA additive can regulate the solvation sheath of Zn2+ and form a protective layer on the surface of the Zn metal anode. This broadens the electrochemical stability window of the aqueous electrolyte and enables uniform deposition of Zn. On the cathode side, the Cl- anions from PEA enter the PANI chain during charge and release fewer water molecules surrounding the oxidized PANI, thus suppressing harmful side reactions. When used in a Zn||PANI battery, this cathode/anode compatible electrolyte exhibits excellent rate performance and long cycle life, making it highly attractive for practical applications.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA