Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 197
Filtrar
1.
Plant Cell ; 35(6): 2293-2315, 2023 05 29.
Artículo en Inglés | MEDLINE | ID: mdl-36929908

RESUMEN

Terpenoids constitute the largest class of plant primary and secondary metabolites with a broad range of biological and ecological functions. They are synthesized from isopentenyl diphosphate and dimethylallyl diphosphate, which in plastids are condensed by geranylgeranyl diphosphate synthases (GGPPSs) to produce GGPP (C20) for diterpene biosynthesis and by geranyl diphosphate synthases (GPPSs) to form GPP (C10) for monoterpene production. Depending on the plant species, unlike homomeric GGPPSs, GPPSs exist as homo- and heteromers, the latter of which contain catalytically inactive GGPPS-homologous small subunits (SSUs) that can interact with GGPPSs. By combining phylogenetic analysis with functional characterization of GGPPS homologs from a wide range of photosynthetic organisms, we investigated how different GPPS architectures have evolved within the GGPPS protein family. Our results reveal that GGPPS gene family expansion and functional divergence began early in nonvascular plants, and that independent parallel evolutionary processes gave rise to homomeric and heteromeric GPPSs. By site-directed mutagenesis and molecular dynamics simulations, we also discovered that Leu-Val/Val-Ala pairs of amino acid residues were pivotal in the functional divergence of homomeric GPPSs and GGPPSs. Overall, our study elucidated an evolutionary path for the formation of GPPSs with different architectures from GGPPSs and uncovered the molecular mechanisms involved in this differentiation.


Asunto(s)
Dimetilaliltranstransferasa , Diterpenos , Farnesiltransferasa/genética , Farnesiltransferasa/metabolismo , Filogenia , Dimetilaliltranstransferasa/genética , Dimetilaliltranstransferasa/metabolismo , Diterpenos/metabolismo
2.
J Am Chem Soc ; 146(6): 3675-3688, 2024 02 14.
Artículo en Inglés | MEDLINE | ID: mdl-38305736

RESUMEN

The extracellular matrix (ECM) in the tumor microenvironment (TME) and upregulated immune checkpoints (ICs) on antitumor immune cells impede the infiltration and killing effect of T cells, creating an immunosuppressive TME. Herein, a cholesterol oxidase (CHO) and lysyl oxidase inhibitor (LOX-IN-3) co-delivery copper-dibenzo-[g,p]chrysene-2,3,6,7,10,11,14,15-octaol single-site nanozyme (Cu-DBCO/CL) was developed. The conjugated organic ligand and well-distributed Cu-O4 sites endow Cu-DBCO with unique redox capabilities, enabling it to catalyze O2 and H2O2 to ·O2- and ·OH. This surge of reactive oxygen species (ROS) leads to impaired mitochondrial function and insufficient ATP supply, impacting the function of copper-transporting ATPase-1 and causing dihydrolipoamide S-acetyltransferase oligomerization-mediated cuproptosis. Moreover, multiple ROS storms and glutathione peroxidase 4 depletion also induce lipid peroxidation and trigger ferroptosis. Simultaneously, the ROS-triggered release of LOX-IN-3 reshapes the ECM by inhibiting lysyl oxidase activity and further enhances the infiltration of cytotoxic T lymphocytes (CD8+ T cells). CHO-triggered cholesterol depletion not only increases ·OH generation but also downregulates the expression of ICs such as PD-1 and TIM-3, restoring the antitumor activity of tumor-infiltrating CD8+ T cells. Therefore, Cu-DBCO/CL exhibits efficient properties in activating a potent antitumor immune response by cascade-enhanced CD8+ T cell viability. More importantly, ECM remodeling and cholesterol depletion could suppress the metastasis and proliferation of the tumor cells. In short, this immune nanoremodeler can greatly enhance the infiltration and antitumor activity of T cells by enhancing tumor immunogenicity, remodeling ECM, and downregulating ICs, thus achieving effective inhibition of tumor growth and metastasis.


Asunto(s)
Linfocitos T CD8-positivos , Neoplasias , Humanos , Proteína-Lisina 6-Oxidasa , Cobre , Peróxido de Hidrógeno , Especies Reactivas de Oxígeno , Colesterol , Línea Celular Tumoral , Inmunoterapia , Microambiente Tumoral
3.
Small ; 20(25): e2310268, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38195818

RESUMEN

Electrocatalytic nitrogen reduction reaction (NRR) paves a sustainable way to produce NH3 but suffering from the relatively low NH3 yield and poor selectivity. High-performance NRR catalysts and a deep insight into the structure-performance relationship are higher desired. Herein, a molten-salt approach is developed to synthesize tiny CeO2 nanoparticles anchored by ultra-thin MoN nanosheets as advanced catalysts for NRR. Specifically, a considerably high NH3 yield rate of 27.5 µg h-1 mg-1 with 17.2% Faradaic efficiency (FE) can be achieved at -0.3 V vs (RHE) under ambient conditions. Experimental and density functional theory (DFT) calculations further point out that the incorporation of MoN with CeO2 can promotes the enlargement of the electron deficient area of nitrogen vacancy site. The enlarged electron deficient area contributes to the accommodation of lone pair electrons of N2, which dramatically improves the N2 adsorption/activation and the key intermediates (*NNH and *NH3) generation, thus boosting the NRR performance.

4.
Angew Chem Int Ed Engl ; 63(8): e202317594, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38183405

RESUMEN

Hydrocracking catalysis is a key route to plastic waste upgrading, but the acid site-driven C-C cleavage step is relatively sluggish in conventional bifunctional catalysts, dramatically effecting the overall efficiency. We demonstrate here a facile and efficient way to boost the reactivity of acid sites by introducing Ce promoters into Pt/HY catalysts, thus achieving a better metal-acid balance. Remarkably, 100 % of low-density polyethylene (LDPE) can be converted with 80.9 % selectivity of liquid fuels over the obtained Pt/5Ce-HY catalysts at 300 °C in 2 h. For comparison, Pt/HY only gives 38.8 % of LDPE conversion with 21.3 % selectivity of liquid fuels. Through multiple experimental studies on the structure-performance relationship, the Ce species occupied in the supercage are identified as the actual active sites, which possess remarkably-improved adsorption capability towards short-chain intermediates.

5.
Angew Chem Int Ed Engl ; : e202407733, 2024 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-38735859

RESUMEN

The variability of CO2 hydrogenation reaction demands new potential strategies to regulate the fine structure of the catalysts for optimizing the reaction pathways. Herein, we report a dual-site strategy to boost the catalytic efficiency of CO2-to-methanol conversion. A new descriptor, τ, was initially established for screening the promising candidates with low-temperature activation capability of CO2, and sequentially a high-performance catalyst was fabricated centred with oxophilic Mo single atoms, who was further decorated with Pt nanoparticles. In CO2 hydrogenation, the obtained dual-site catalysts possess a remarkably-improved methanol generation rate (0.27 mmol gcat. -1 h-1). For comparison, the singe-site Mo and Pt-based catalysts can only produce ethanol and formate acid at a relatively low reaction rate (0.11 mmol gcat. -1 h-1 for ethanol and 0.034 mmol gcat. -1 h-1 for formate acid), respectively. Mechanism studies indicate that the introduction of Pt species could create an active hydrogen-rich environment, leading to the alterations of the adsorption configuration and conversion pathways of the *OCH2 intermediates on Mo sites. As a result, the catalytic selectivity was successfully switched.

6.
J Am Chem Soc ; 145(16): 8965-8978, 2023 04 26.
Artículo en Inglés | MEDLINE | ID: mdl-37058189

RESUMEN

Immunotherapy is currently the most promising treatment strategy for long-term tumor regression. However, current cancer immunotherapy shows low response rates due to insufficient immunogenicity of tumor cells. Herein, we report a strategy to keep tumor cells highly immunogenic by triggering cascade immunogenic tumor ferroptosis. We developed a six-enzyme co-expressed nanoplatform: lipoxygenase (LOX) and phospholipase A2 (PLA2)-co-loaded FeCo/Fe-Co dual-metal atom nanozyme (FeCo/Fe-Co DAzyme/PL), which can not only induce initial immunogenic tumor ferroptosis through its own multi-enzyme mimetic activities but also up-regulate arachidonic acid (AA) expression to synergize with CD8+ T cell-derived IFN-γ to induce ACSL4-mediated immunogenic tumor ferroptosis. During this process, FeCo/Fe-Co DAzyme/PL can induce lipid peroxidation (LPO) by efficiently generating reactive oxygen species (ROS) and depleting GSH and GPX4 at tumor sites. Additionally, free AA released from PLA2 catalysis is converted into arachidonyl-CoA under the activation of ACSL4 stimulated by IFN-γ, which is further incorporated into phospholipids on membranes and peroxidized with the participation of LOX. Consequently, FeCo/Fe-Co DAzyme/PL can promote irreversible cascade immunogenic ferroptosis through multiple ROS storms, GSH/GPX4 depletion, LOX catalysis, and IFN-γ-mediated ACSL4 activation, constructing an effective pathway to overcome the drawbacks of current immunotherapy.


Asunto(s)
Ferroptosis , Neoplasias , Humanos , Interferón gamma , Ácido Araquidónico/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Fosfolipasas A2 , Neoplasias/metabolismo , Línea Celular Tumoral
7.
J Am Chem Soc ; 145(4): 2264-2270, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36689604

RESUMEN

The limitations of conventional strategies in finely controlling the composition and structure demand new promotional effects for upgrading the reverse water-gas shift (RWGS) catalysts for enhanced fuel production. We report the design and synthesis of a hetero-dual-site catalyst for boosting RWGS performance by controllably loading Fe atoms at the neighboring Pt atom on the surface of commercial CeO2. The Fe-Pt/CeO2 exhibits a remarkably high catalytic performance (TOFPt: 43,519 h-1) for CO2 to CO conversion with ∼100% CO selectivity at a relatively low temperature of 350 °C. Furthermore, the catalyst retains over 80% activity after 200 h of continuous operation. The experimental and computational investigations reveal a "two-way synergistic effect", where Fe atoms can not only serve as promotors to alter the charge density of Pt atoms but also be activated by the excess active hydrogen species generated by Pt atoms, enhancing catalytic activity and stability.

8.
Small ; 19(6): e2205313, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36461734

RESUMEN

Electrochemical Nc reduction has been regarded as one of the most promising approaches to producing ammonia under mild conditions, but there are remaining pressing challenges in improving the reaction rate and efficiency. Herein, an unconventional galvanic replacement reaction is reported to fabricate a unique hierarchical structure composed of Fe3 O4 -CeO2 bimetallic nanotubes covered by Fe2 O3 ultrathin nanosheets. Control experiments reveal that CeO2 species play the essential role of stabilizer for Fe2+ cations. Compared with bare CeO2 and Fe2 O3 nanotubes, the as-obtained Fe2 O3 /Fe3 O4 -CeO2 possesses a remarkably enhanced NH3 yield rate (30.9 µg h-1 mgcat -1 ) and Faradaic efficiency (26.3%). The enhancement can be attributed to the hierarchical feature that makes electrodes more easily to contact with electrolytes. More importantly, as verified by density functional theory calculations, the generation of Fe2 O3 -Fe3 O4 heterogeneous junctions can efficiently optimize the reaction pathways, and the energy barrier of the potential determining step (the *N2 hydrogenates into *N*NH) is significantly decreased.

9.
Small ; 19(35): e2300903, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37096905

RESUMEN

Hydrogenolysis is an effective method for converting polyolefins into high-value chemicals. For the supported catalysts commonly used, the size of active metals is of great importance. In this study, it is discovered that the activity of CeO2 -supported Ru single atom, nanocluster, and nanoparticle catalysts shows a volcanic trend in low-density polyethylene (LDPE) hydrogenolysis. Compared with CeO2 supported Ru single atoms and nanoparticles, CeO2 -supported Ru nanoclusters possess the highest conversion efficiency, as well as the best selectivity toward liquid alkanes. Through comprehensive investigations, the metal-support interactions (MSI) and hydrogen spillover effect are revealed as the two key factors in the reaction. On the one hand, the MSI is strongly related to the Ru surface states and the more electronegative Ru centers are beneficial to the activation of CH and CC bonds. On the other hand, the hydrogen spillover capability directly affects the affinity of catalysts and active H atoms, and increasing this affinity is advantageous to the hydrogenation of alkane species. Decreasing the Ru sizes can promote the MSI, but it can also reduce the hydrogen spillover effect. Therefore, only when the two effects achieve a balance, as is the case in CeO2 -supported Ru nanoclusters, can the hydrogenolysis activity be promoted to the optimal value.

10.
Small ; : e2309664, 2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-38057126

RESUMEN

Nanozymes with peroxidase-mimic activity have recently emerged as effective strategies for eliminating infections. However, challenges in enhancing catalytic activities and the ability to target bacteria have hindered the broader application of nanozymes in bacterial infections. Herein, a novel nanozyme based on mesoporous CeO2 nanosphere and meso-tetra(4-carboxyphenyl)porphine (TCPP) encapsulated within pathogen-activated macrophage membranes, demonstrates photodynamic capability coupled with photo-enhanced chemodynamic therapy for selective and efficient antibacterial application against infected wounds. Interestingly, the expression of Toll-like receptors accordingly upregulates when macrophages are co-cultured with specific bacteria, thereby facilitating to recognition of the pathogen-associated molecular patterns originating from bacteria. The CeO2 not only serve as carriers for TCPP, but also exhibit intrinsic peroxidase-like catalytic activity. Consequently, Staphylococcus aureus (S. aureus)-activated macrophage membrane-coated CeO2 -TCPP (S-MM@CeO2 -TCPP) generated singlet oxygen, and simultaneously promoted photo-enhanced chemodynamic therapy, significantly boosting reactive oxygen species (ROS) to effectively eliminate bacteria. S-MM@CeO2 -TCPP specifically targeted S. aureus via Toll-like receptor, thereby directly disrupting bacterial structural integrity to eradicate S. aureus in vitro and relieve bacteria-induced inflammation to accelerate infected wound healing in vivo. By selectively targeting specific bacteria and effectively killing pathogens, such strategy provides a more efficient and reliable alternative for precise elimination of pathogens and inflammation alleviation in microorganism-infected wounds.

11.
Chemistry ; 29(49): e202300583, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37367498

RESUMEN

Electrocatalytic CO2 reduction reaction (CO2 RR) is a promising and green approach for reducing atmospheric CO2 concentration and achieving high-valued conversion of CO2 under the carbon-neutral policy. In CO2 RR, the dual-site metal catalysts (DSMCs) have received wide attention for their ingenious design strategies, abundant active sites, and excellent catalytic performance attributed to the synergistic effect between dual-site in terms of activity, selectivity and stability, which plays a key role in catalytic reactions. This review provides a systematic summary and detailed classification of DSMCs for CO2 RR, describes the mechanism of synergistic effects in catalytic reactions, and also introduces in situ characterization techniques commonly used in CO2 RR. Finally, the main challenges and prospects of dual-site metal catalysts and even multi-site catalysts for CO2 recycling are analyzed. It is believed that based on the understanding of bimetallic site catalysts and synergistic effects in CO2 RR, well-designed high-performance, low-cost electrocatalysts are promising for achieving CO2 conversion, electrochemical energy conversion and storage in the future.

12.
BMC Cancer ; 23(1): 853, 2023 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-37697257

RESUMEN

BACKGROUND: Cervical cancer is a common gynecological malignancy. Gene microarray found that TCP11 gene was highly expressed in cervical cancer. However, the effect of TCP11 gene on the proliferation, apoptosis and migration of cervical cancer cells and its underlying molecular mechanisms are unclear. METHODS: GEPIA database, tissue microarray, western blot and qRT-PCR were used to analyze the expression of TCP11 gene in cervical cancer tissues and cells and its relationship with patients' survival rate. The cell cycle and apoptosis were detected by flow cytometry, and the expressions of cell cycle and apoptosis related molecules and EMT-related molecules were detected by Western blot and qRT-PCR. RESULTS: The results showed that TCP11 gene was highly expressed in cervical cancer tissues and cells compared with normal cervical tissues and cells, and its expression was positively correlated with patients' survival rate. The results of proliferation and migration assays showed that TCP11 overexpression inhibited the proliferation and migration of HeLa and SiHa cells. The results showed that TCP11 overexpression blocked the cell cycle of HeLa and SiHa cells, decreased the expression of CDK1 and Cyclin B1, and increased the apoptosis and the expression of caspase-3, cleaved-caspase-3 and cleaved-PARP. TCP11 overexpression increased the protein and mRNA expression of EMT-related molecules ZO-1 and E-cadherin. Conversely, TCP11 knockdown promoted the proliferation of HeLa and SiHa cells and the migration of HeLa cells. CONCLUSIONS: TCP11 overexpression significantly inhibited the occurrence and development of cervical cancer cells, it may be a potentially beneficial biomarker for cervical cancer.


Asunto(s)
Proteínas de la Membrana , Neoplasias del Cuello Uterino , Femenino , Humanos , Apoptosis/genética , Caspasa 3 , División Celular , Expresión Génica , Células HeLa , Neoplasias del Cuello Uterino/genética , Proteínas de la Membrana/genética
13.
BMC Cancer ; 23(1): 79, 2023 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-36694148

RESUMEN

BACKGROUND: Cervical cancer is currently estimated to be the fourth most common cancer among women worldwide and the leading cause of cancer-related deaths in some of the world's poorest countries. C/EBPß has tumor suppressor effects because it is necessary for oncogene-induced senescence. However, C/EBPß also has an oncogenic role. The specific role of C/EBPß in cervical cancer as a tumor suppressor or oncoprotein is unclear. OBJECTIVE: To explore the role of the C/EBPß protein in cervical tumorigenesis and progression. METHODS: Quantitative RT-PCR was used to analyze C/EBPß (15 cervical cancer tissue samples and 15 corresponding normal cervical tissue samples), miR-661, and MTA1 mRNA expression in clinical samples (10 cervical cancer tissue samples and 10 corresponding normal cervical tissue samples). Immunohistochemistry was used to analyze C/EBPß (381 clinical samples), Ki67 (80 clinical samples) and PCNA ( 60 clinical samples) protein expression. MALDI-TOF MassARRAY was used to analyze C/EBPß gene methylation (13 cervical cancer tissues and 13 corresponding normal cervical tissues). Cell proliferation was analyzed by CCK-8 in cervical cancer cell lines. Western blotting and immunohistochemistry were performed to detect C/EBPß protein expression levels, and mRNA expression was analyzed by quantitative RT-PCR analysis. Flow cytometry was performed to measure cell cycle distribution and cell apoptosis. Colony formation, Transwell, cell invasion, and wound healing assays were performed to detect cell migration and invasion. RESULTS: C/EBPß protein expression was significantly reduced in cervical cancer tissues compared with cervicitis tissues (P < 0.01). Ki67 protein and PCNA protein expression levels were significantly higher in cervical cancer tissues compared with cervicitis tissues. The rate of C/EBPß gene promoter methylation of CpG12, 13, 14 and CpG19 in cervical cancer tissues was significantly increased compared with normal cervical tissue (P < 0.05). In addition, C/EBPß was overexpressed in cervical cancer cells and this overexpression inhibited cell proliferation, migration, invasion, arrested cells in S phase, and promoted apoptosis. CONCLUSIONS: We have demonstrated that C/EBPß decreased in cervical cancer tissues and overexpression of the C/EBPß gene in cervical cancer cells could inhibit proliferation, invasion and migration.


Asunto(s)
MicroARNs , Neoplasias del Cuello Uterino , Cervicitis Uterina , Femenino , Humanos , Carcinogénesis/genética , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Transformación Celular Neoplásica/genética , Regulación Neoplásica de la Expresión Génica , Antígeno Ki-67/metabolismo , MicroARNs/genética , Antígeno Nuclear de Célula en Proliferación/metabolismo , Proteínas Represoras/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transactivadores/genética , Neoplasias del Cuello Uterino/genética , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patología , Cervicitis Uterina/genética
14.
Angew Chem Int Ed Engl ; 62(28): e202302877, 2023 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-37165571

RESUMEN

Reducible oxide-supported noble metal nanoparticles exhibit high activity in catalyzing many important oxidation reactions. However, atom migration under harsh reaction conditions leads to deactivation of the catalyst. Meanwhile, single-atom catalysts demonstrate enhanced stability, but often suffer from poor catalytic activity owing to the ionized surface states. In this work, we simultaneously address the poor activity and stability issues by synthesizing highly active and durable rhodium (Rh) single-atom catalysts through a "wrap-bake-peel" process. The pre-coated SiO2 layer during synthesis of catalyst plays a crucial role in not only protecting CeO2 support against sintering, but also donating electron to weaken the Ce-O bond, producing highly loaded Rh single atoms on the CeO2 support exposed with high-index {210} facets. Benefiting from the unique electronic structure of CeO2 {210} facets, more oxygen vacancies are generated along with the deposition of more electropositive Rh single atoms, leading to remarkably improved catalytic performance in CO oxidation.

15.
Small ; 18(29): e2201271, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35726120

RESUMEN

The incorporation of a transition metal into a noble metal for the formation of nanoalloys paves a potential way to modulate the electronic structures and spatial arrangement modes, thereby manipulating the target catalysis under the desired reaction pathways. Herein, a top-down synthetic route to fabricate IrCo nanoalloys with delicately designed compositions and morphologies at an extremely low calcination temperature of 200 °C is reported, which efficiently breaks through the thermodynamic limitations caused by the large atomic radii and electronegativity discrepancies between Co and Ir. A high-performance selective hydrogenation system enabled by the synthesized IrCo nanoalloys and the light irradiation is further established. Significantly, the unique properties of IrCo alloy, involving the special capability of generating local heating rather than hot electrons under light irradiation (the hot-electron effect was considered detrimental to hydrogenation reactions), as well as the highly polarized surface which aids in the hydrogen transfer from borane-ammonia complex (AB) to 4-nitrostyrene (4-NS) are discovered.

16.
Inorg Chem ; 61(25): 9801-9807, 2022 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-35696705

RESUMEN

As an important factor affecting global agricultural output, pesticides have a significant impact on the ecosystem. It is an urgent task to accurately and conveniently detect pesticide residues after their application. Herein, a fluorescent dye@MOF platform was designed via the encapsulation of rhodamine B (RhB) into the MOF structure (named RhB@HNU-48), which can significantly enhance the sensing sensitivity of alachlor with an ultralow detection limit of 0.59 ppb. The improved sensitivity of RhB@HNU-48 to pesticides was attributed to the host-guest interactions that affect the excitation and emission spectra of the composites. Based on the sensing capability of RhB@HNU-48, a logic gate was built to evaluate the safety level of alachlor residues in rivers and soil. The preparation of photofunctionalized MOF composites through modulation of host-guest interactions offers a promising strategy for the construction of desired sensors for agricultural residues.


Asunto(s)
Elementos de la Serie de los Lantanoides , Estructuras Metalorgánicas , Plaguicidas , Acetamidas , Ecosistema , Estructuras Metalorgánicas/química
17.
Inorg Chem ; 61(1): 456-463, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34932332

RESUMEN

Developing fluorescent materials with multiple and tunable emissions under different conditions is necessary to meet the growing demand for optical anticounterfeiting technology. Different modes of fluorescence emission can be obtained by loading multiple fluorescent components into metal-organic frameworks (MOFs) and modulating the interaction among them for multiple anticounterfeiting purposes. Herein, a Cd-based MOF (HNU-60) was constructed as a host to encapsulate both lanthanide ions and carbon quantum dots. Multiple fluorescence emissions can be achieved by modulation of host-guest and guest-guest interaction, which holds promise for multiple anticounterfeiting applications. This work opens the opportunity to construct the hybrid MOF-based materials with controlled fluorescence properties for emerging anticounterfeiting applications in various fields.

18.
Int J Mol Sci ; 23(7)2022 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-35409266

RESUMEN

Orange (OR) is a DnaJ-like zinc finger protein with both nuclear and plastidial localizations. OR, and its orthologs, are highly conserved in flowering plants, sharing a characteristic C-terminal tandem 4× repeats of the CxxCxxxG signature. It was reported to trigger chromoplast biogenesis, promote carotenoid accumulation in plastids of non-pigmented tissues, and repress chlorophyll biosynthesis and chloroplast biogenesis in the nucleus of de-etiolating cotyledons cells. Its ectopic overexpression was found to enhance plant resistance to abiotic stresses. Here, we report that the expression of OR in Arabidopsis thaliana was upregulated by drought treatment, and seedlings of the OR-overexpressing (OE) lines showed improved growth performance and survival rate under drought stress. Compared with the wild-type (WT) and OR-silencing (or) lines, drought-stressed OE seedlings possessed lower contents of reactive oxygen species (such as H2O2 and O2-), higher activities of both superoxide dismutase and catalase, and a higher level of proline content. Our enzymatic assay revealed a relatively higher activity of Δ1-pyrroline-5-carboxylate synthase (P5CS), a rate-limiting enzyme for proline biosynthesis, in drought-stressed OE seedlings, compared with the WT and or lines. We further demonstrated that the P5CS activity could be enhanced by supplementing exogenous OR in our in vitro assays. Taken together, our results indicated a novel contribution of OR to drought tolerance, through its impact on proline biosynthesis.


Asunto(s)
Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis , Sequías , Regulación de la Expresión Génica de las Plantas , Proteínas del Choque Térmico HSP40 , Peróxido de Hidrógeno/metabolismo , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/metabolismo , Prolina/metabolismo , Plantones/genética , Plantones/metabolismo , Estrés Fisiológico , Dedos de Zinc
19.
Chem Soc Rev ; 49(3): 736-764, 2020 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-31922174

RESUMEN

Multicomponent nanomaterials (MCNs) fabricated by rationally coupling distinct compositions in a controlled manner have shown improved chemical and physical properties when compared to any of the individual components. Such hybridization can not only efficiently retain the respective features of each ingredient but also provide more possibilities for controlling the surface states through as-generated synergistic effects. Great demands have been placed on the innovation of synthetic strategies for efficient fabrication with precisely controlled size, shape, composition and hybridization of nanostructures. Recently, redox interaction-engaged strategies (RIESs), which are performed by manipulating distinct precursors with suitable reduction and oxidation capabilities, have attracted tremendous interest of researchers, and great achievements have been made. During the synthesis process, no mass exchange occurs, which is completely different from a classic galvanic replacement reaction (GRR). Electron transmission and particle generation occur simultaneously, resulting in the formation of strongly coupled MCNs. Herein, we attempt to offer a systematic review of current achievements based on RIESs, beginning with a detailed summary of the operational process, sphere of applications and formation mechanism. Next, we focus on the improved performance of as-fabricated materials in catalytic reactions, and a comprehensive discussion of the structure-performance relationships is also presented. Last, we end with a brief conclusion and some prospects for future development trends in this promising research area.

20.
Angew Chem Int Ed Engl ; 60(43): 23154-23158, 2021 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-34382327

RESUMEN

One of the most pressing challenges in single-atom catalysis is the manipulation of the coordination environment of central metals to maximize the catalyst performance. Herein, we fabricated a high-performance catalyst (Co-SNC) by introducing S into the neighboring position of the Co-N4 coordination. The developed ball-milling method enabled large-scale synthesis, that over 4.7 g of Co-SNC can be produced in one pot. In benzylamine coupling reaction, Co-SNC exhibited the highest conversion of 97.5 % with 99 % selectivity toward N-benzylidenebenzylamine in 10 h among various Co catalysts. Density functional theory calculations revealed the crucial role of S atoms, which serve as the active sites for O2 activation, leaving the Co atoms free to adsorb benzylamine. Consequently, the adsorption energies of O2 and benzylamine were significantly increased. Our strategy suggests a feasible approach to enhance catalytic performance by delicately integrating dual active sites into a single catalyst unit.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA