Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 258
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Plant J ; 118(1): 90-105, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38113332

RESUMEN

Necrotrophic fungal plant pathogens employ cell death-inducing proteins (CDIPs) to facilitate infection. However, the specific CDIPs and their mechanisms in pathogenic processes of Sclerotinia sclerotiorum, a necrotrophic pathogen that causes disease in many economically important crop species, have not yet been clearly defined. This study found that S. sclerotiorum secretes SsXyl2, a glycosyl hydrolase family 11 xylanase, at the late stage of hyphal infection. SsXyl2 targets the apoplast of host plants to induce cell death independent of xylanase activity. Targeted disruption of SsXyl2 leads to serious impairment of virulence, which can be recovered by a catalytically impaired SsXyl2 variant, thus supporting the critical role of cell death-inducing activity of SsXyl2 in establishing successful colonization of S. sclerotiorum. Remarkably, infection by S. sclerotiorum induces the accumulation of Nicotiana benthamiana hypersensitive-induced reaction protein 2 (NbHIR2). NbHIR2 interacts with SsXyl2 at the plasma membrane and promotes its localization to the cell membrane and cell death-inducing activity. Furthermore, gene-edited mutants of NbHIR2 displayed increased resistance to the wild-type strain of S. sclerotiorum, but not to the SsXyl2-deletion strain. Hence, SsXyl2 acts as a CDIP that manipulates host cell physiology by interacting with hypersensitive induced reaction protein to facilitate colonization by S. sclerotiorum. These findings provide valuable insights into the pathogenic mechanisms of CDIPs in necrotrophic pathogens and lead to a more promising approach for breeding resistant crops against S. sclerotiorum.


Asunto(s)
Ascomicetos , Fitomejoramiento , Plantas , Virulencia , Nicotiana , Muerte Celular , Enfermedades de las Plantas/microbiología
2.
Proc Natl Acad Sci U S A ; 119(42): e2207326119, 2022 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-36215478

RESUMEN

Electrochemical conversion of CO2 into formate is a promising strategy for mitigating the energy and environmental crisis, but simultaneously achieving high selectivity and activity of electrocatalysts remains challenging. Here, we report low-dimensional SnO2 quantum dots chemically coupled with ultrathin Ti3C2Tx MXene nanosheets (SnO2/MXene) that boost the CO2 conversion. The coupling structure is well visualized and verified by high-resolution electron tomography together with nanoscale scanning transmission X-ray microscopy and ptychography imaging. The catalyst achieves a large partial current density of -57.8 mA cm-2 and high Faradaic efficiency of 94% for formate formation. Additionally, the SnO2/MXene cathode shows excellent Zn-CO2 battery performance, with a maximum power density of 4.28 mW cm-2, an open-circuit voltage of 0.83 V, and superior rechargeability of 60 h. In situ X-ray absorption spectroscopy analysis and first-principles calculations reveal that this remarkable performance is attributed to the unique and stable structure of the SnO2/MXene, which can significantly reduce the reaction energy of CO2 hydrogenation to formate by increasing the surface coverage of adsorbed hydrogen.

3.
Nano Lett ; 24(25): 7645-7653, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38875704

RESUMEN

Understanding the nucleation and growth mechanism of 3d transition bimetallic nanocrystals (NCs) is crucial to developing NCs with tailored nanostructures and properties. However, it remains a significant challenge due to the complexity of 3d bimetallic NCs formation and their sensitivity to oxygen. Here, by combining in situ electron microscopy and synchrotron X-ray techniques, we elucidate the nucleation and growth pathways of Fe-Ni NCs. Interestingly, the formation of Fe-Ni NCs emerges from the assimilation of Fe into Ni clusters together with the reduction of Fe-Ni oxides. Subsequently, these NCs undergo solid-state phase transitions, resulting in two distinct solid solutions, ultimately dominated by γ-Fe3Ni2. Furthermore, we deconvolve the interplays between local coordination and electronic state concerning the growth temperature. We directly visualize the oxidation-state distributions of Fe and Ni at the nanoscale and investigate their changes. This work may reshape and enhance the understanding of nucleation and growth in atomic crystallization.

4.
Small ; 20(21): e2307758, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38100187

RESUMEN

Metal halide nanocrystals (MHNCs) embedded in a polymer matrix as flexible X-ray detector screens is an effective strategy with the advantages of low cost, facile preparation, and large area flexibility. However, MHNCs easily aggregate during preparation, recombination, under mechanical force, storage, or high operating temperature. Meanwhile, it shows an unmatched refractive index with polymer, resulting in low light yield. The related stability and properties of the device remain a huge unrevealed challenge. Herein, a composite screen (CZBM@AG-PS) by integrating MHNCs (Cs2ZnBr4: Mn2+ as an example) into silica aerogel (AG) and embedded in polystyrene (PS) is successfully developed. Further characterization points to the high porosity AG template that can effectively improve the dispersion of MHNCs in polymer detector screens, essentially decreasing nonradiative transition, Rayleigh scattering, and performance aging induced by aggregation in harsh environments. Furthermore, the higher light output and lower optical crosstalk are also achieved by a novel light propagation path based on the MHNCs/AG and AG/PS interfaces. Finally, the optimized CZBM@AG-PS screen shows much enhanced light yield, spatial resolution, and temperature stability. Significantly, the strategy is proven universal by the performance tests of other MHNCs embedded composite films for ultra-stable and efficient X-ray imaging.

5.
J Environ Manage ; 355: 120504, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38447513

RESUMEN

Ammonia-oxidation process directly contribute to soil nitrous oxide (N2O) emissions in agricultural soils. However, taxonomy of the key nitrifiers (within ammonia oxidising bacteria (AOB), archaea (AOA) and complete ammonia oxidisers (comammox Nitrospira)) responsible for substantial N2O emissions in agricultural soils is unknown, as is their regulation by soil biotic and abiotic factors. In this study, cumulative N2O emissions, nitrification rates, abundance and community structure of nitrifiers were investigated in 16 agricultural soils from major crop production regions of China using microcosm experiments with amended nitrogen (N) supplemented or not with a nitrification inhibitor (nitrapyrin). Key nitrifier groups involved in N2O emissions were identified by comparative analyses of the different treatments, combining sequencing and random forest analyses. Soil cumulative N2O emissions significantly increased with soil pH in all agricultural soils. However, they decreased with soil organic carbon (SOC) in alkaline soils. Nitrapyrin significantly inhibited soil cumulative N2O emissions and AOB growth, with a significant inhibition of the AOB Nitrosospira cluster 3a.2 (D11) abundance. One Nitrosospira multiformis-like OTU phylotype (OTU34), which was classified within the AOB Nitrosospira cluster 3a.2 (D11), had the greatest importance on cumulative N2O emissions and its growth significantly depended on soil pH and SOC contents, with higher growth at high pH and low SOC conditions. Collectively, our results demonstrate that alkaline soils with low SOC contents have high N2O emissions, which were mainly driven by AOB Nitrosospira cluster 3a.2 (D11). Nitrapyrin can efficiently reduce nitrification-related N2O emissions by inhibiting the activity of AOB Nitrosospira cluster 3a.2 (D11). This study advances our understanding of key nitrifiers responsible for high N2O emissions in agricultural soils and their controlling factors, and provides vital knowledge for N2O emission mitigation in agricultural ecosystems.


Asunto(s)
Ecosistema , Suelo , Suelo/química , Amoníaco/química , Carbono , Oxidación-Reducción , Archaea , Nitrificación , Microbiología del Suelo
6.
Nat Mater ; 21(6): 681-688, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35606427

RESUMEN

Atomically dispersed single-atom catalysts have the potential to bridge heterogeneous and homogeneous catalysis. Dozens of single-atom catalysts have been developed, and they exhibit notable catalytic activity and selectivity that are not achievable on metal surfaces. Although promising, there is limited knowledge about the boundaries for the monometallic single-atom phase space, not to mention multimetallic phase spaces. Here, single-atom catalysts based on 37 monometallic elements are synthesized using a dissolution-and-carbonization method, characterized and analysed to build the largest reported library of single-atom catalysts. In conjunction with in situ studies, we uncover unified principles on the oxidation state, coordination number, bond length, coordination element and metal loading of single atoms to guide the design of single-atom catalysts with atomically dispersed atoms anchored on N-doped carbon. We utilize the library to open up complex multimetallic phase spaces for single-atom catalysts and demonstrate that there is no fundamental limit on using single-atom anchor sites as structural units to assemble concentration-complex single-atom catalyst materials with up to 12 different elements. Our work offers a single-atom library spanning from monometallic to concentration-complex multimetallic materials for the rational design of single-atom catalysts.

7.
Altern Ther Health Med ; 29(8): 389-395, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37632970

RESUMEN

Triple-negative breast cancer (TNBC) presents the most adverse prognosis due to its pronounced invasive and metastatic features. Existing research has highlighted that metformin, a prevalent diabetes medication, possesses strong anti-tumor properties, particularly in inhibiting tumor invasion and metastasis. This study delves deeper into the impact of metformin on TNBC by examining changes in proliferation, apoptosis, invasion, migration, and adhesion of TNBC cells, specifically MDA-MB-231, post-metformin exposure. The treatment of MDA-MB-231 with metformin in immunodeficient nude mice led to discernible changes in tumor metrics such as size, weight, lymph node engagement, and angiogenesis. Post-treatment, MDA-MB-231 cells exhibited a marked decline in proliferation, invasion, migration, and adhesion, alongside a significant rise in apoptosis. In the in vivo model with nude mice, tumors displayed notable reductions in size and weight post-metformin exposure. Furthermore, there was a pronounced decline in lymph node plasma cell proliferation and tumor angiogenesis. Through the use of both Enzyme-Linked Immunosorbent Assay and Real-Time Fluorescence Quantification, it was ascertained that the expression of Signal Transducer and Activator of Transcription 3 (STAT3) saw significant augmentation, while expressions of Matrix Metallopeptidase-2 (MMP-2), Matrix Metallopeptidase-9 (MMP-9), Interleukin-6 (IL-6), and Interleukin-7 (IL-7) decreased markedly. This suggests metformin's potential efficacy against TNBC, potentially mediated via the STAT3 signaling pathway and interleukins 6 and 7.


Asunto(s)
Metformina , Neoplasias de la Mama Triple Negativas , Humanos , Animales , Ratones , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/patología , Ratones Desnudos , Metformina/farmacología , Metformina/uso terapéutico , Proliferación Celular , Línea Celular Tumoral , Metaloproteasas/farmacología , Metaloproteasas/uso terapéutico
8.
Angew Chem Int Ed Engl ; 62(20): e202300989, 2023 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-36932632

RESUMEN

Decarbonizing N2 conversion is particularly challenging, but essential for sustainable development of industry and agriculture. Herein, we achieve electrocatalytic activation/reduction of N2 on X/Fe-N-C (X=Pd, Ir and Pt) dual-atom catalysts under ambient condition. We provide solid experimental evidence that local hydrogen radical (H*) generated on the X site of the X/Fe-N-C catalysts can participate in the activation/reduction of N2 adsorbed on the Fe site. More importantly, we reveal that the reactivity of X/Fe-N-C catalysts for N2 activation/reduction can be well adjusted by the activity of H* generated on the X site, i.e., the interaction between the X-H bond. Specifically, X/Fe-N-C catalyst with the weakest X-H bonding exhibits the highest H* activity, which is beneficial to the subsequent cleavage of X-H bond for N2 hydrogenation. With the most active H*, the Pd/Fe dual-atom site promotes the turnover frequency of N2 reduction by up to 10 times compared with the pristine Fe site.

9.
Biochem Biophys Res Commun ; 607: 166-173, 2022 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-35381387

RESUMEN

Von Willebrand Factor (VWF) can promote platelet adhesion to the post-atherosclerotic regions to initiate thrombosis. The synthesis and secretion of VWF are important functions of endothelial cells (ECs). However, the mechanism through which blood flow regulates endothelial secretion of VWF remains unclear. We utilized a parallel-plate flow apparatus to apply fluid shear stress to human umbilical vein endothelial cells (HUVECs). Compared with pulsatile shear stress that mimics laminar flow in the straight parts of arteries or upstream of atherosclerotic stenosis sites, short-term exposure to oscillatory shear stress (OS) that mimics disturbed flow increased VWF secretion independent of affecting synaptosomal-associated protein 23 (SNAP23) expression and promoted the translocation of SNAP23 to the cell membrane. Vimentin associated with SNAP23, and this association was enhanced by OS or histamine. Acrylamide, a reagent that disrupts vimentin intermediate filaments, prevented histamine/OS-induced SNAP23 translocation, as well as VWF secretion. Immunofluorescence analysis revealed that the polarity of the vimentin intermediate filament network decreased after stimulation with histamine or OS. In addition, inhibition of protein kinase A (PKA) or G protein coupled receptor 68 (GPR68) eliminated the histamine/OS-induced phosphorylation of vimentin at Ser38 and secretion of VWF. Furthermore, syntaxin 7 might assist with the translocation of SNAP23 to the cell membrane, thus playing a role in promoting VWF secretion. The GPR68/PKA/vimentin signaling pathway may represent a novel mechanism for the regulation of SNAP23-mediated VWF secretion by ECs under OS and provide strategies for the prevention of atherosclerosis-related thrombosis.


Asunto(s)
Trombosis , Factor de von Willebrand , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Histamina/metabolismo , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Filamentos Intermedios/metabolismo , Mecanotransducción Celular , Proteínas Qb-SNARE/metabolismo , Proteínas Qc-SNARE/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Estrés Mecánico , Trombosis/metabolismo , Vimentina/metabolismo , Factor de von Willebrand/metabolismo
10.
Chembiochem ; 23(21): e202200244, 2022 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-35822393

RESUMEN

Protein modulation by light illumination enables the investigation of biological function in high spatiotemporal precision. Compared to genetic methods, the small molecule approach is uniquely suited for modulating endogenous proteins. Endogenous protein modulation in live cells with small molecules and light has recently advanced on three distinctive frontiers: i) the infrared-light-induced or localized decaging of small molecules by photolysis, ii) the visible-light-induced photocatalytic releasing of small molecules, and iii) the small-molecule-ligand-directed caging for photomodulation of proteins. Together, these methods provide powerful chemical biology tool kits for spatiotemporal modulation of endogenous proteins with potential therapeutic applications. This Concept article aims to inspire organic chemists and chemical biologists to delve into this burgeoning endogenous protein modulation field for new biological discoveries.


Asunto(s)
Luz , Proteínas , Fotólisis , Ligandos
11.
Nature ; 538(7623): 79-83, 2016 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-27556943

RESUMEN

Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules, serve as model systems in studies of phase transitions in liquid systems, behave as 'colloidal surfactants' and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient, but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles, and nanoparticles with surface ripples or a 'raspberry' surface morphology. Here we demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. These patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.

12.
BMC Vet Res ; 18(1): 410, 2022 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-36411417

RESUMEN

BACKGROUND: The holin-endolysin lysis system plays an essential role in the phage life cycle. Endolysins are promising alternatives to antibiotics, and have been successfully used against Gram-positive bacteria. However, a few endolysins can externally lyse Gram-negative bacteria, due to the inaccessible peptidoglycan layer covered by the envelope. RESULTS: This study investigated the lysis system of a new Siphoviridae bacteriophage vB_Sal-S-S10 (S10), which, that was isolated from broiler farms, was found to be able to infect 51.4% (37/72) of tested S. enteritidis strains. Phage S10 genome had a classic holin-endolysin lysis system, except that one holin and one endolysin gene were functionally annotated. The orf 22 adjacent to the lysis cassette was identified as a new endolysin gene. Antibacterial activity assays showed that holin had an intracellular penetrating activity against S. enteritidis 35; both endolysins acted on the cell envelope of S. enteritidis 35 and showed a natural extracellular antibacterial activity, leading to a ~ 1 log titer decrease in 30 min. Protein characterization of lysin1 and lysin2 revealed that the majority of the N-terminus and the C-terminus were hydrophobic amino acids or positively charged. CONCLUSION: In this study, a new Salmonella phage vB_Sal-S-S10 (S10) was characterized and showed an ideal development prospect. Phage S10 has a classic holin-endolysin lysis system, carrying an overlapping holin-lysin gene and a novel lysin gene. Both endolysins coded by lysin genes could externally lyse S. enteritidis. The natural extracellular antibacterial character of endolysins would provide necessary information for the development of engineering endolysin as the antibiotic alternative against the infection with multidrug-resistant gram-negative bacteria.


Asunto(s)
Bacteriófagos , Animales , Bacteriófagos/metabolismo , Salmonella enteritidis , Pollos , Antibacterianos/farmacología , Antibacterianos/metabolismo
13.
Angew Chem Int Ed Engl ; 61(17): e202115472, 2022 04 19.
Artículo en Inglés | MEDLINE | ID: mdl-35199422

RESUMEN

The control of endogenous protein activity with light inside live cells is helpful for the high spatiotemporal probing of their dynamic roles. Herein, we report the first small-molecule-ligand-directed caging approach to control the endogenous human O6 -alkylguanine-DNA alkyltransferase (AGT) activity with light, and the caged AGT is constructed from the native intracellular AGT. The photo-responsive O6 -benzylguanine derivative O6 -NBG3 is developed to site-specifically cage the AGT's catalytic cysteine residue, and the light irradiation on-demand restores AGT's activity in vitro, in bacteria, and in mammalian cells. With O6 -NBG3, the alkylated AGT is dealkylated for the first time to recover the DNA repair activity in breast cancer MCF-7 cells by the dose-dependent light irradiation. This decaging strategy enables the localized modulation of endogenous AGT activity with high temporal precision without genetic engineering, which holds great potential for therapeutic applications.


Asunto(s)
Transferasas Alquil y Aril , Guanina , Animales , Guanina/química , Humanos , Ligandos , Mamíferos/metabolismo , O(6)-Metilguanina-ADN Metiltransferasa/química
14.
Angew Chem Int Ed Engl ; 61(52): e202212005, 2022 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-36314469

RESUMEN

Atropisomers bearing multiple stereogenic axes are of increasing importance to the field of material science, pharmaceuticals, and catalysis. However, the atroposelective construction of multi-axis atropisomers remains rare and challenging, due to the intrinsical difficulties in the stereo-control of the multiple stereogenic axes. Herein, we demonstrate a single-step construction of a new class of 1,2-diaxially chiral triaryl α-pyranones by an N-heterocyclic carbene organocatalytic asymmetric [3+3] annulation of well-designed alkynyl acylazolium precursors and enolizable sterically hindered 2-aryl ketones. The protocol features broad substrate scope (>50 examples), excellent stereo-control (most cases >20 : 1 dr, up to 99.5 : 0.5 er), and potentially useful synthetic applications. The success of this reaction relies on the rational design of structurally matched reaction partners and the careful selection of the asymmetric catalytic system. DFT calculations have also been performed to discover and rationalize the origin of the high stereoselectivity of this reaction.

15.
Environ Microbiol ; 23(2): 588-599, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32249528

RESUMEN

Viruses can affect microbial dynamics, metabolism and biogeochemical cycles in aquatic ecosystems. However, viral diversity and functions in agricultural soils are poorly known, especially in the rhizosphere. We used virome analysis of eight rhizosphere and bulk soils to study viral diversity and potential biogeochemical impacts in an agro-ecosystem. The order Caudovirales was the predominant viral type in agricultural soils, with Siphoviridae being the most abundant family. Phylogenetic analysis of the terminase large subunit of Caudovirales identified high viral diversity and three novel groups. Viral community composition differed significantly between bulk and rhizosphere soils. Soil pH was the main environmental driver of the viral community structure. Remarkably, abundant auxiliary carbohydrate-active enzyme (CAZyme) genes were detected in viromes, including glycoside hydrolases, carbohydrate esterases and carbohydrate-binding modules. These results demonstrate that virus-encoded putative auxiliary metabolic genes or metabolic genes that may change bacterial metabolism and indirectly contribute to biogeochemical cycling, especially carbon cycling, in agricultural soil.


Asunto(s)
Biodiversidad , Microbiología del Suelo , Virus/aislamiento & purificación , Agricultura , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Ecosistema , Concentración de Iones de Hidrógeno , Filogenia , Rizosfera , Suelo/química , Virus/clasificación , Virus/genética
16.
Environ Microbiol ; 23(4): 1907-1924, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-32996254

RESUMEN

Plants harbour highly diverse mycobiomes which sustain essential functions for host health and productivity. However, ecological processes that govern the plant-mycobiome assembly, interactions and their impact on ecosystem functions remain poorly known. Here we characterized the ecological role and community assembly of both abundant and rare fungal taxa along the soil-plant continuums (rhizosphere, phyllosphere and endosphere) in the maize-wheat/barley rotation system under different fertilization practices at two contrasting sites. Our results indicate that mycobiome assembly is shaped predominantly by compartment niche and host species rather than by environmental factors. Moreover, crop-associated fungal communities are dominated by few abundant taxa mainly belonging to Sordariomycetes and Dothideomycetes, while the majority of diversity within mycobiomes are represented by rare taxa. For plant compartments, the abundant sub-community is mainly determined by stochastic processes. In contrast, the rare sub-community is more sensitive to host selection and mainly governed by deterministic processes. Furthermore, our results demonstrate that rare taxa play an important role in fungal co-occurrence network and ecosystem functioning like crop yield and soil enzyme activities. These results significantly advance our understanding of crop mycobiome assembly and highlight the key role of rare taxa in sustaining the stability of crop mycobiomes and ecosystem functions.


Asunto(s)
Productos Agrícolas/microbiología , Micobioma , Ecosistema , Hongos/genética , Rizosfera , Microbiología del Suelo
17.
New Phytol ; 229(2): 1091-1104, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32852792

RESUMEN

Plant microbiomes are essential to host health and productivity but the ecological processes that govern crop microbiome assembly are not fully known. Here we examined bacterial communities across 684 samples from soils (rhizosphere and bulk soil) and multiple compartment niches (rhizoplane, root endosphere, phylloplane, and leaf endosphere) in maize (Zea mays)-wheat (Triticum aestivum)/barley (Hordeum vulgare) rotation system under different fertilization practices at two contrasting sites. Our results demonstrate that microbiome assembly along the soil-plant continuum is shaped predominantly by compartment niche and host species rather than by site or fertilization practice. From soils to epiphytes to endophytes, host selection pressure sequentially increased and bacterial diversity and network complexity consequently reduced, with the strongest host effect in leaf endosphere. Source tracking indicates that crop microbiome is mainly derived from soils and gradually enriched and filtered at different plant compartment niches. Moreover, crop microbiomes were dominated by a few dominant taxa (c. 0.5% of bacterial phylotypes), with bacilli identified as the important biomarker taxa for wheat and barley and Methylobacteriaceae for maize. Our work provides comprehensive empirical evidence on host selection, potential sources and enrichment processes for crop microbiome assembly, and has important implications for future crop management and manipulation of crop microbiome for sustainable agriculture.


Asunto(s)
Microbiota , Microbiología del Suelo , Bacterias , Raíces de Plantas , Rizosfera
18.
Opt Express ; 29(4): 5993-5999, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33726130

RESUMEN

The photonic crystal (PC) has been demonstrated to be very effective in improving the extraction efficiency of light-emitting diodes (LEDs). In this paper, high-brightness AlGaInP-based vertical LEDs (VLEDs) with surface PC (SPCLED) and embedded PC (EPCLED) were successfully fabricated. Compared with normal LED (NLED), photoluminescence intensities of SPCLED and EPCLED have been improved up to 30% and 60%, respectively. And the reflection patterns of SPCLED and EPCLED were periodic bright points array, showing the ability to control light in PC. Electroluminescent measurements show that three kinds of LEDs have similar threshold voltages. Simultaneously, the light output power (LOP) of SPCLED and EPCLED has been improved up to 24% and 11% at 200 mA, respectively, in comparison to NLEDs. But the LOP decays earlier for EPCLED due to the excessive heat production. Furthermore, it is demonstrated that the SPCLED and EPCLED luminous uniformity is better. This kind of high brightness PCLED is promising in improving the properties of all kinds of LEDs, especially mini LEDs and micro LEDs.

19.
BMC Endocr Disord ; 21(1): 92, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33933044

RESUMEN

BACKGROUND: The prevalence of diabetes is increasing worldwide. Our study aimed to estimate the changing trends in the prevalence and incidence of diagnosed type 2 diabetes mellitus (T2DM) among Xiamen residents and the floating population using real-world data. METHOD: We used real-world data from the System of Xiamen Citizens Health Information from 2014 to 2019 to estimate the changing trends in the prevalence and incidence of diagnosed T2DM. The System included the diagnosis of diabetes and the prescription of hypoglycemic drugs. Prevalent cases of T2DM were individuals who were diagnosed with T2DM and/or using hypoglycemic drugs. Incident cases were individuals with diagnosed T2DM and/or using hypoglycemic drugs in 2014 or 2019 who had not been diagnosed and/or did not use hypoglycemic drugs in the past. RESULTS: In 2014 and 2019, the prevalence of T2DM in Xiamen was 4.04 and 4.84%, respectively. In 2014 and 2019, the incidence rate of T2DM in Xiamen was 14.1 per 1000 person-year and 15.0 per 1000 person-year, respectively. There was a significant increase in both the prevalence (Prevalence difference: 0.80, 95%CI 0.76-0.83%, P < 0.001) and the incidence of T2DM (Incidence difference: 0.9, 95%CI 0.7-1.1, P < 0.001). in Xiamen. The prevalence and incidence of T2DM in people aged 18-39 increased significantly (P < 0.001), while the prevalence and incidence of T2DM in people aged 40-69 reduced significantly (P < 0.001). CONCLUSIONS: There was a significant increase in the prevalence and incidence of T2DM in Xiamen from 2014 to 2019 especially among those with younger age.


Asunto(s)
Diabetes Mellitus Tipo 2/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , China/epidemiología , Femenino , Historia del Siglo XXI , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Adulto Joven
20.
Angew Chem Int Ed Engl ; 60(1): 345-350, 2021 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-32939894

RESUMEN

The electrochemical reduction of N2 to NH3 is emerging as a promising alternative for sustainable and distributed production of NH3 . However, the development has been impeded by difficulties in N2 adsorption, protonation of *NN, and inhibition of competing hydrogen evolution. To address the issues, we design a catalyst with diatomic Pd-Cu sites on N-doped carbon by modulation of single-atom Pd sites with Cu. The introduction of Cu not only shifts the partial density of states of Pd toward the Fermi level but also promotes the d-2π* coupling between Pd and adsorbed N2 , leading to enhanced chemisorption and activated protonation of N2 , and suppressed hydrogen evolution. As a result, the catalyst achieves a high Faradaic efficiency of 24.8±0.8 % and a desirable NH3 yield rate of 69.2±2.5 µg h-1 mgcat. -1 , far outperforming the individual single-atom Pd catalyst. This work paves a pathway of engineering single-atom-based electrocatalysts for enhanced ammonia electrosynthesis.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA