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1.
J Transl Med ; 22(1): 395, 2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38685028

RESUMEN

BACKGROUND: Current cancer therapies often fall short in addressing the complexities of malignancies, underscoring the urgent need for innovative treatment strategies. RNA interference technology, which specifically suppresses gene expression, offers a promising new approach in the fight against tumors. Recent studies have identified a novel immunostimulatory small-interfering RNA (siRNA) with a unique sequence (sense strand, 5'-C; antisense strand, 3'-GGG) capable of activating the RIG-I/IRF3 signaling pathway. This activation induces the release of type I and III interferons, leading to an effective antiviral immune response. However, this class of immunostimulatory siRNA has not yet been explored in cancer therapy. METHODS: IsiBCL-2, an innovative immunostimulatory siRNA designed to suppress the levels of B-cell lymphoma 2 (BCL-2), contains a distinctive motif (sense strand, 5'-C; antisense strand, 3'-GGG). Glioblastoma cells were subjected to 100 nM isiBCL-2 treatment in vitro for 48 h. Morphological changes, cell viability (CCK-8 assay), proliferation (colony formation assay), migration/invasion (scratch test and Transwell assay), apoptosis rate, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were evaluated. Western blotting and immunofluorescence analyses were performed to assess RIG-I and MHC-I molecule levels, and ELISA was utilized to measure the levels of cytokines (IFN-ß and CXCL10). In vivo heterogeneous tumor models were established, and the anti-tumor effect of isiBCL-2 was confirmed through intratumoral injection. RESULTS: IsiBCL-2 exhibited significant inhibitory effects on glioblastoma cell growth and induced apoptosis. BCL-2 mRNA levels were significantly decreased by 67.52%. IsiBCL-2 treatment resulted in an apoptotic rate of approximately 51.96%, accompanied by a 71.76% reduction in MMP and a 41.87% increase in ROS accumulation. Western blotting and immunofluorescence analyses demonstrated increased levels of RIG-I, MAVS, and MHC-I following isiBCL-2 treatment. ELISA tests indicated a significant increase in IFN-ß and CXCL10 levels. In vivo studies using nude mice confirmed that isiBCL-2 effectively impeded the growth and progression of glioblastoma tumors. CONCLUSIONS: This study introduces an innovative method to induce innate signaling by incorporating an immunostimulatory sequence (sense strand, 5'-C; antisense strand, 3'-GGG) into siRNA, resulting in the formation of RNA dimers through Hoogsteen base-pairing. This activation triggers the RIG-I signaling pathway in tumor cells, causing further damage and inducing a potent immune response. This inventive design and application of immunostimulatory siRNA offer a novel perspective on tumor immunotherapy, holding significant implications for the field.


Asunto(s)
Apoptosis , Glioma , ARN Interferente Pequeño , Humanos , Animales , Línea Celular Tumoral , Glioma/terapia , Glioma/patología , Glioma/genética , ARN Interferente Pequeño/metabolismo , Ratones Desnudos , Proteína 58 DEAD Box/metabolismo , Proteína 58 DEAD Box/genética , Proliferación Celular , Movimiento Celular , Ensayos Antitumor por Modelo de Xenoinjerto , Ratones , Receptores Inmunológicos/metabolismo , Receptores Inmunológicos/genética , Especies Reactivas de Oxígeno/metabolismo , Invasividad Neoplásica , Supervivencia Celular
2.
Appl Microbiol Biotechnol ; 108(1): 165, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38252275

RESUMEN

Ferulic acid (FA) and p-coumaric acid (p-CA) are hydroxycinnamic acid inhibitors that are mainly produced during the pretreatment of lignocellulose. To date, the inhibitory mechanism of hydroxycinnamic acid compounds on Saccharomyces cerevisiae has not been fully elucidated. In this study, liquid chromatography-mass spectrometry (LC-MS) and scanning electron microscopy (SEM) were used to investigate the changes in S. cerevisiae cells treated with FA and p-CA. In this experiment, the control group was denoted as group CK, the FA-treated group was denoted as group F, and the p-CA-treated group was denoted as group P. One hundred different metabolites in group F and group CK and 92 different metabolites in group P and group CK were selected and introduced to metaboanalyst, respectively. A total of 38 metabolic pathways were enriched in S. cerevisiae under FA stress, and 27 metabolic pathways were enriched in S. cerevisiae under p-CA stress as identified through Kyoto Encyclopaedia of Genes and Genomes (KEGG) analysis. The differential metabolites involved included S-adenosine methionine, L-arginine, and cysteine, which were significantly downregulated, and acetyl-CoA, L-glutamic acid, and L-threonine, which were significantly upregulated. Analysis of differential metabolic pathways showed that the differentially expressed metabolites were mainly related to amino acid metabolism, nucleotide metabolism, fatty acid degradation, and the tricarboxylic acid cycle (TCA). Under the stress of FA and p-CA, the metabolism of some amino acids was blocked, which disturbed the redox balance in the cells and destroyed the synthesis of most proteins, which was the main reason for the inhibition of yeast cell growth. This study provided a strong scientific reference to improve the durability of S. cerevisiae against hydroxycinnamic acid inhibitors. KEY POINTS: • Morphological changes of S. cerevisiae cells under inhibitors stress were observed. • Changes of the metabolites in S. cerevisiae cells were explored by metabolomics. • One of the inhibitory effects on yeast is due to changes in the metabolic network.


Asunto(s)
Ácidos Cumáricos , Saccharomyces cerevisiae , Ácidos Cumáricos/farmacología , Metabolómica , Aminoácidos
3.
Front Plant Sci ; 14: 1242089, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37636117

RESUMEN

Brown planthopper (Nilaparvata lugens Stål, BPH) is one of the most destructive pests of rice. Non-coding RNA plays an important regulatory role in various biological processes. However, comprehensive identification and characterization of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) in BPH-infested rice have not been performed. Here, we performed a genome-wide analysis of lncRNAs and circRNAs in BPH6-transgenic (resistant, BPH6G) and Nipponbare (susceptible, NIP) rice plants before and after BPH feeding (early and late stage) via deep RNA-sequencing. A total of 310 lncRNAs and 129 circRNAs were found to be differentially expressed. To reveal the different responses of resistant and susceptible rice to BPH herbivory, the potential functions of these lncRNAs and circRNAs as competitive endogenous RNAs (ceRNAs) were predicted and investigated using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. Dual-luciferase reporter assays revealed that miR1846c and miR530 were targeted by the lncRNAs XLOC_042442 and XLOC_028297, respectively. In responsive to BPH infestation, 39 lncRNAs and 21 circRNAs were predicted to combine with 133 common miRNAs and compete for miRNA binding sites with 834 mRNAs. These mRNAs predictably participated in cell wall organization or biogenesis, developmental growth, single-organism cellular process, and the response to stress. This study comprehensively identified and characterized lncRNAs and circRNAs, and integrated their potential ceRNA functions, to reveal the rice BPH-resistance network. These results lay a foundation for further study on the functions of lncRNAs and circRNAs in the rice-BPH interaction, and enriched our understanding of the BPH-resistance response in rice.

4.
Front Plant Sci ; 14: 1200014, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37404541

RESUMEN

The brown planthopper (BPH) (Nilaparvata lugens) sucks rice sap causing leaves to turn yellow and wither, often leading to reduced or zero yields. Rice co-evolved to resist damage by BPH. However, the molecular mechanisms, including the cells and tissues, involved in the resistance are still rarely reported. Single-cell sequencing technology allows us to analyze different cell types involved in BPH resistance. Here, using single-cell sequencing technology, we compared the response offered by the leaf sheaths of the susceptible (TN1) and resistant (YHY15) rice varieties to BPH (48 hours after infestation). We found that the 14,699 and 16,237 cells (identified via transcriptomics) in TN1 and YHY15 could be annotated using cell-specific marker genes into nine cell-type clusters. The two rice varieties showed significant differences in cell types (such as mestome sheath cells, guard cells, mesophyll cells, xylem cells, bulliform cells, and phloem cells) in the rice resistance mechanism to BPH. Further analysis revealed that although mesophyll, xylem, and phloem cells are involved in the BPH resistance response, the molecular mechanism used by each cell type is different. Mesophyll cell may regulate the expression of genes related to vanillin, capsaicin, and ROS production, phloem cell may regulate the cell wall extension related genes, and xylem cell may be involved in BPH resistance response by controlling the expression of chitin and pectin related genes. Thus, rice resistance to BPH is a complicated process involving multiple insect resistance factors. The results presented here will significantly promote the investigation of the molecular mechanisms underlying the resistance of rice to insects and accelerate the breeding of insect-resistant rice varieties.

5.
Front Plant Sci ; 14: 1213257, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37426975

RESUMEN

Introduction: The brown planthopper (Nilaparvata lugens Stål, BPH) is one of the most economically significant pests of rice. The Bph30 gene has been successfully cloned and conferred rice with broad-spectrum resistance to BPH. However, the molecular mechanisms by which Bph30 enhances resistance to BPH remain poorly understood. Methods: Here, we conducted a transcriptomic and metabolomic analysis of Bph30-transgenic (BPH30T) and BPH-susceptible Nipponbare plants to elucidate the response of Bph30 to BPH infestation. Results: Transcriptomic analyses revealed that the pathway of plant hormone signal transduction enriched exclusively in Nipponbare, and the greatest number of differentially expressed genes (DEGs) were involved in indole 3-acetic acid (IAA) signal transduction. Analysis of differentially accumulated metabolites (DAMs) revealed that DAMs involved in the amino acids and derivatives category were down-regulated in BPH30T plants following BPH feeding, and the great majority of DAMs in flavonoids category displayed the trend of increasing in BPH30T plants; the opposite pattern was observed in Nipponbare plants. Combined transcriptomics and metabolomics analysis revealed that the pathways of amino acids biosynthesis, plant hormone signal transduction, phenylpropanoid biosynthesis and flavonoid biosynthesis were enriched. The content of IAA significantly decreased in BPH30T plants following BPH feeding, and the content of IAA remained unchanged in Nipponbare. The exogenous application of IAA weakened the BPH resistance conferred by Bph30. Discussion: Our results indicated that Bph30 might coordinate the movement of primary and secondary metabolites and hormones in plants via the shikimate pathway to enhance the resistance of rice to BPH. Our results have important reference significance for the resistance mechanisms analysis and the efficient utilization of major BPH-resistance genes.

6.
Mol Breed ; 43(1): 1, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37312871

RESUMEN

The grain protein content (GPC) of rice is an important factor that determines its nutritional, cooking, and eating qualities. To date, although a number of genes affecting GPC have been identified in rice, most of them have been cloned using mutants, and only a few genes have been cloned in the natural population. In this study, 135 significant loci were detected in a genome-wide association study (GWAS), many of which could be repeatedly detected across different years and populations. Four minor quantitative trait loci affecting rice GPC at four significant association loci, qPC2.1, qPC7.1, qPC7.2, and qPC1.1, were further identified and validated in near-isogenic line F2 populations (NIL-F2), explaining 9.82, 43.4, 29.2, and 13.6% of the phenotypic variation, respectively. The role of the associated flo5 was evaluated with knockdown mutants, which exhibited both increased grain chalkiness rate and GPC. Three candidate genes in a significant association locus region were analyzed using haplotype and expression profiles. The findings of this study will help elucidate the genetic regulatory network of protein synthesis and accumulation in rice through cloning of GPC genes and provide new insights on dominant alleles for marker-assisted selection in the genetic improvement of rice grain quality. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01347-z.

7.
Environ Sci Technol ; 57(20): 7858-7866, 2023 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-37161886

RESUMEN

Selective catalytic reduction (SCR) of NOx with NH3 is the most efficient technology for NOx emissions control, but the activity of catalysts decreases exponentially with the decrease in reaction temperature, hindering the application of the technology in low-temperature SCR to treat industrial stack gases. Here, we present an industrially practicable technology to significantly enhance the SCR activity at low temperatures (<250 °C). By introducing an appropriate amount of O3 into the simulated stack gas, we find that O3 can stoichiometrically oxidize NO to generate NO2, which enables NO reduction to follow the fast SCR mechanism so as to accelerate SCR at low temperatures, and, in particular, an increase in SCR rate by more than four times is observed over atom-pair V1-W1 active sites supported on TiO2(001) at 200 °C. Using operando SCR tests and in situ diffuse reflectance infrared Fourier transform spectra, we reveal that the introduction of O3 allows SCR to proceed along a NH4NO3-mediated Langmuir-Hinshelwood model, in which the adsorbed nitrate species speed up the re-oxidation of the catalytic sites that is the rate-limiting step of SCR, thus leading to the enhancement of activity at low temperatures. This technology could be applicable in the real stack gas conditions because O3 exclusively oxidizes NO even in the co-presence of SO2 and H2O, which provides a general strategy to improve low-temperature SCR efficacy from another perspective beyond designing catalysts.


Asunto(s)
Amoníaco , Gases , Dominio Catalítico , Amoníaco/química , Oxidación-Reducción , Temperatura , Catálisis
8.
Int J Mol Sci ; 24(3)2023 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-36768236

RESUMEN

Cold damage is one of the most important environmental factors influencing crop growth, development, and production. In this study, we generated a pair of near-isogenic lines (NILs), Towada and ZL31, and Towada showed more cold sensitivity than ZL31 in the rice seedling stage. To explore the transcriptional regulation mechanism and the reason for phenotypic divergence of the two lines in response to cold stress, an in-depth comparative transcriptome study under cold stress was carried out. Our analysis uncovered that rapid and high-amplitude transcriptional reprogramming occurred in the early stage of cold treatment. GO enrichment and KEGG pathway analysis indicated that genes of the response to stress, environmental adaptation, signal transduction, metabolism, photosynthesis, and the MAPK signaling pathway might form the main part of the engine for transcriptional reprogramming in response to cold stress. Furthermore, we identified four core genes, OsWRKY24, OsCAT2, OsJAZ9, and OsRR6, that were potential candidates affecting the cold sensitivity of Towada and ZL31. Genome re-sequencing analysis between the two lines revealed that only OsWRKY24 contained sequence variations which may change its transcript abundance. Our study not only provides novel insights into the cold-related transcriptional reprogramming process, but also highlights the potential candidates involved in cold stress.


Asunto(s)
Respuesta al Choque por Frío , Oryza , Respuesta al Choque por Frío/genética , Plantones/genética , Oryza/metabolismo , Perfilación de la Expresión Génica , Transcriptoma , Frío , Regulación de la Expresión Génica de las Plantas
9.
Transplant Proc ; 55(2): 354-362, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36841703

RESUMEN

BACKGROUND: To investigate the social participation (SP) of renal transplantation (RT) recipients and analyze the influencing factors. DESIGN: Cross-sectional study. METHODS: Data were collected from RT recipients reviewed within the Urology Outpatient Clinic of a tertiary class-A hospital in Hebei, China between October 2018 and October 2019. RESULTS: The total mean score of an SP questionnaire for RT recipients was 37.77 ± 2.74. The mean score per item in each dimension showed that the scores for leisure, activity, and voluntary participation in social life were the highest, indicating low participation. Educational level, household income, occupation, preoperative employment, creatinine level in the transplanted kidney, medication compliance, depression, and anxiety could explain 77% of the variation in the SP level. CONCLUSIONS: There are many factors affecting the SP levels of RT recipients. Clinicians should comprehensively evaluate RT recipients before and after surgery, formulate health education programs, and improve the SP level.


Asunto(s)
Trasplante de Riñón , Humanos , Trasplante de Riñón/efectos adversos , Estudios Transversales , Participación Social , China , Riñón
10.
Angew Chem Int Ed Engl ; 61(52): e202212703, 2022 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-36321806

RESUMEN

Effective adsorption and speedy surface reactions are vital requirements for efficient active sites in catalysis, but it remains challenging to maximize these two functions simultaneously. We present a solution to this issue by designing a series of atom-pair catalytic sites with tunable electronic interactions. As a case study, NO selective reduction occurring on V1 -W1 /TiO2 is chosen. Experimental and theoretical results reveal that the synergistic electron effect present between the paired atoms enriches high-energy spin charge around the Fermi level, simultaneously rendering reactant (NH3 or O2 ) adsorption more effective and subsequent surface reactions speedier as compared with single V or W atom alone, and hence higher reaction rates. This strategy enables us to rationally design a high-performance V1 -Mo1 /TiO2 catalyst with optimized vanadium(IV)-molybdenum(V) electronic interactions, which has exceptional activity significantly higher than the commercial or reported catalysts.

11.
Chem Commun (Camb) ; 58(82): 11587-11590, 2022 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-36168912

RESUMEN

We tune the valence state of single Au atoms anchored on CeO2(100) by treating the catalyst in H2 at different temperatures and obtain a series of Au1/CeO2(100). The transition from Au1+0.9 to Au1+0.3 leads to an enhancement of the CO oxidation activity of Au1/CeO2(100) by one order of magnitude. This work is of significance for an in-depth understanding of reaction mechanisms and rational design of high-performance catalysts.

12.
PeerJ ; 10: e13587, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35910769

RESUMEN

Background: The brown planthopper (BPH), Nilaparvata lugens (Stål), is a very destructive pest that poses a major threat to rice plants worldwide. BPH and rice have developed complex feeding and defense strategies in the long-term co-evolution. Methods: To explore the molecular mechanism of BPH's adaptation to resistant rice varieties, the lncRNA expression profiles of two virulent BPH populations were analyzed. The RNA-seq method was used to obtain the lncRNA expression data in TN1 and YHY15. Results: In total, 3,112 highly reliable lncRNAs in TN1 and YHY15 were identified. Compared to the expression profiles between TN1 and YHY15, 157 differentially expressed lncRNAs, and 675 differentially expressed mRNAs were identified. Further analysis of the possible regulation relationships between differentially expressed lncRNAs and differentially expressed mRNAs, identified three pair antisense targets, nine pair cis-regulation targets, and 3,972 pair co-expressed targets. Function enriched found arginine and proline metabolism, glutathione metabolism, and carbon metabolism categories may significantly affect the adaptability in BPH when it is exposed to susceptible and resistant rice varieties. Altogether, it provided scientific data for the study of lncRNA regulation of brown planthopper resistance to rice. These results are helpful in the development of new control strategies for host defense against BPH and breeding rice for high yield.


Asunto(s)
Hemípteros , Oryza , ARN Largo no Codificante , Animales , Perfilación de la Expresión Génica , Hemípteros/genética , Oryza/genética , Fitomejoramiento , ARN Largo no Codificante/genética
13.
J Plant Physiol ; 273: 153688, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35462224

RESUMEN

Insect pests and weeds are the two major biotic factors affecting crop yield in the modern agricultural system. In this study, a brown planthopper (BPH) resistance gene (BPH9) and glufosinate tolerance gene (bar) were stacked into a single T-DNA cassette and transformed into an indica rice (Oryza sativa L.) line Guangzhan 63-4S. A stable transgenic line H23 with a single T-DNA insert was generated, with the T-DNA cassette located on chromosome 3. Field resistance trial using H23 revealed high tolerance to glufosinate and excellent resistance to BPH. These results propose H23 as valuable germplasm for BPH-resistance and glufosinate-tolerance breeding in rice.


Asunto(s)
Hemípteros , Oryza , Animales , Aminobutiratos , Oryza/genética , Fitomejoramiento
14.
Front Oncol ; 12: 836953, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35345443

RESUMEN

Glioma is the most common malignant tumor of the central nervous system (CNS), with high degree of malignancy and poor prognosis. The gut microbiome (GM) is composed of microorganisms with different properties and functions, which play an important role in human physiology and biological activities. It has been proved that GM can affect the development of glioma through natural immunity, but whether GM can affect glioma through adaptive immunity and whether there are some microorganisms in the GM that may affect glioma growth still remain unclear. In our study, we evaluated the relationship between GM and glioma. We proved that (I) glioma growth can induce structural changes of mouse GM, including the decreased abundance of Bacteroidia and increased abundance of Firmicutes. (II) GM dysbiosis can downregulate Foxp3 expression in the brain and promote glioma growth. A balanced environment of GM can upregulate the expression of Foxp3 in the brain and delay the development of glioma. (III) The increased abundance of Bacteroidia is associated with accelerated glioma progression, while its decreased abundance is associated with delayed glioma progression, which may be one of the key microorganisms affecting glioma growth. This study is helpful to reveal the relationship between GM and glioma development and provide new ideas for adjuvant therapy of glioma.

15.
PLoS One ; 16(11): e0260133, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34807926

RESUMEN

Grain shape strongly influences the economic value and grain yield of rice. Thus, identifying quantitative trait loci (QTLs) for grain shape has been a longstanding goal in rice genetic research and breeding programs. Single nucleotide polymorphism (SNP) markers are ubiquitous in the rice genome and are more abundant and evenly distributed on the 12 rice chromosomes than traditional markers. An F2 population was genotyped using the RICE6K SNP array to elucidate the mechanisms governing grain shape. Thirty-five QTLs for grain shape were detected on 11 of 12 chromosomes over 2 years. The major QTL cluster qGS7 was detected in both years and displayed strong genetic effects on grain length and width, showing consistency with GL7/GW7. Some minor QTLs were also detected, and the effects of four QTLs on seed size were then validated using BC1F6 populations with residual heterozygous lines in each QTL region. Our findings provide insights into the molecular basis of grain shape as well as additional resources and approaches for producing hybrid high-yield rice varieties.


Asunto(s)
Oryza/citología , Oryza/genética , Sitios de Carácter Cuantitativo/genética , Forma de la Célula/genética , Progresión de la Enfermedad , Grano Comestible/genética , Investigación Genética , Genotipo , Heterocigoto , Fitomejoramiento/métodos , Polimorfismo de Nucleótido Simple/genética , Semillas/citología , Semillas/genética
16.
Phys Chem Chem Phys ; 23(17): 10636-10649, 2021 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-33904542

RESUMEN

Recently, RNA aptamers activating small-molecule fluorophores have been successfully applied to tag and track RNAs in vivo. It is of significance to investigate the molecular mechanism of the fluorophore-RNA aptamer bindings at the atomic level to seek a possible pathway to enhance the fluorescence efficiency of fluorophores. In this work, multiple replica molecular dynamics (MRMD) simulations, essential dynamics (ED) analysis, and hierarchical clustering analysis were coupled to probe the effect of A22U mutation on the binding of two fluorophores, TO1-Biotin (TO1) and TO3-Biotin (TO3), to the Mango-II RNA aptamer (Mango-II). ED analysis reveals that A22U induces alterations in the binding pocket and sites of TO1 and TO3 to the Mango-II, which in turn tunes the fluorophore-RNA interface and changes the interactions of TO1 and TO3 with separate nucleotides of Mango-II. Dynamics analyses also uncover that A22U exerts the opposite impact on the molecular surface areas of the Mango-II and sugar puckers of nucleotides 22 and 23 in Mango-II complexed with TO1 and TO3. Moreover, the calculations of binding free energies suggest that A22U strengthens the binding ability of TO1 to the mutated Mango-II but weakens TO3 to the mutated Mango-II when compared with WT. These findings imply that point mutation in nucleotides possibly tune the fluorescence of fluorophores binding to RNA aptamers, providing a possible scheme to enhance the fluorescence of fluorophores.


Asunto(s)
Aptámeros de Nucleótidos/química , Biotina/química , Colorantes Fluorescentes/química , Simulación de Dinámica Molecular , Sitios de Unión , Colorantes Fluorescentes/síntesis química , Estructura Molecular
17.
Environ Sci Technol ; 55(8): 5435-5441, 2021 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-33724009

RESUMEN

Although ceria-based catalysts serve as an appealing alternative to traditional V2O5-based catalysts for selective catalytic reduction (SCR) of NOx with NH3, the inevitable deactivation caused by SO2 at low temperatures severely hampers the ceria-based catalysts to efficiently control NOx emissions from SO2-containing stack gases. Here, we rationally design a strong sulfur-resistant ceria-based catalyst by tuning the electronic structures of ceria highly dispersed on acidic MoO3 surfaces. By using Ce L3-edge X-ray absorption near edge structure spectra in conjunction with various surface and bulk structural characterizations, we report that the sulfur resistance of the catalysts is closely associated with the electronic states of ceria, particularly expressed by the Ce3+/Ce4+ ratio related to the size of the ceria particles. As the Ce3+/Ce4+ ratio increases up to or over 50%, corresponding to CeO2/MoO3(x %, x ≤ 2.1) with the particle size of approximately 4 nm or less, the non-bulk electronic states of ceria appear, where the catalysts start to show strong sulfur resistance. This work could provide a new strategy for designing sulfur-resistant ceria-based SCR catalysts for controlling NOx emissions at low temperatures.


Asunto(s)
Amoníaco , Azufre , Catálisis , Electrónica , Temperatura
18.
Nat Commun ; 12(1): 1191, 2021 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-33608540

RESUMEN

Atomic metal wires have great promise for practical applications in devices due to their unique electronic properties. Unfortunately, such atomic wires are extremely unstable. Here we fabricate stable atomic silver wires (ASWs) with appreciably unoccupied states inside the parallel tunnels of α-MnO2 nanorods. These unoccupied Ag 4d orbitals strengthen the Ag-Ag bonds, greatly enhancing the stability of ASWs while the presence of delocalized 5s electrons makes the ASWs conducting. These stable ASWs form a coherently oriented three-dimensional wire array of over 10 nm in width and up to 1 µm in length allowing us to connect it to nano-electrodes. Current-voltage characteristics of ASWs show a temperature-dependent insulator-to-metal transition, suggesting that the atomic wires could be used as thermal electrical devices.

19.
Nat Commun ; 11(1): 1532, 2020 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-32210227

RESUMEN

High-performance catalysts are extremely required for controlling NO emission via selective catalytic reduction (SCR), and to acquire a common structural feature of catalytic sites is one key prerequisite for developing such catalysts. We design a single-atom catalyst system and achieve a generic characteristic of highly active SCR catalytic sites. A single-atom Mo1/Fe2O3 catalyst is developed by anchoring single acidic Mo ions on (001) surfaces of reducible α-Fe2O3, and the individual Mo ion and one neighboring Fe ion are thus constructed as one dinuclear site. As the number of the dinuclear sites increases, SCR rates increase linearly but the apparent activation energy remains almost unchanged, evidencing the identity of the dinuclear active sites. We further design W1/Fe2O3 and Fe1/WO3 and find that tuning acid or/and redox properties of dinuclear sites can alter SCR rates. Therefore, this work provides a design strategy for developing improved SCR catalysts via optimizing acid-redox properties of dinuclear sites.

20.
Phys Chem Chem Phys ; 22(4): 2262-2275, 2020 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-31917380

RESUMEN

Recently, fatty acid binding proteins 5 and 7 (FABP5 and FABP7) have been regarded as the prospective targets for clinically treating multiple diseases related to FABPs. In this work, multiple short molecular dynamics (MSMD) simulations followed by binding free energy calculations were performed to investigate the binding selectivity of three inhibitors, namely, 65X, 8KS, and 5M8 toward FABP5 and FABP7. The RMSF analysis suggests that the structural flexibility of FABP5 is stronger than that of FABP7; moreover, the calculated molecular surface area of FABP5 is also larger than that of FABP7. Meanwhile, the results from the cross-correlation analysis show that the inhibitor bindings exert different impacts on the internal dynamics of FABP5 and FABP7. Binding free energies predicted by the molecular mechanics/generalized Born surface area (MM-GBSA) method indicate that the increase in the enthalpy changes caused by the bindings of inhibitors toward FABP7 relative to FABP5 mostly drives the binding selectivity of the inhibitors toward FABP5 versus FABP7. Hierarchical clustering analysis based on the energy contributions of separate residues and calculations of residue-based free energy decompositions were carried out by using the equilibrated MSMD trajectories. The obtained results not only recognize the hot interaction spots of inhibitors with FABP5 and FABP7, but also display that several common residues, namely, (T56, T54), (L60, F58), (E75, E73), (A76, A78), (D79, D77), (R81, R79), (R107, R109), (C120, L118), and (R129, R127) belonging to (FABP5, FABP7) induce obvious binding differences in the inhibitors toward FABP5 and FABP7. Therefore, these residues play significant roles in the binding selectivities of inhibitors toward FABP5 and FABP7.


Asunto(s)
Proteína de Unión a los Ácidos Grasos 7/antagonistas & inhibidores , Proteínas de Unión a Ácidos Grasos/antagonistas & inhibidores , Simulación de Dinámica Molecular , Proteínas Supresoras de Tumor/antagonistas & inhibidores , Sitios de Unión , Análisis por Conglomerados , Entropía , Proteína de Unión a los Ácidos Grasos 7/metabolismo , Proteínas de Unión a Ácidos Grasos/metabolismo , Humanos , Enlace de Hidrógeno , Unión Proteica , Estructura Terciaria de Proteína , Proteínas Supresoras de Tumor/metabolismo
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