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1.
Development ; 151(20)2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-38646855

RESUMO

Ecdysone-induced protein 93 (E93), known as the 'adult-specifier' transcription factor in insects, triggers metamorphosis in both hemimetabolous and holometabolous insects. Although E93 is conserved in ametabolous insects, its spatiotemporal expression and physiological function remain poorly understood. In this study, we first discover that, in the ametabolous firebrat Thermobia domestica, the previtellogenic ovary exhibits cyclically high E93 expression, and E93 mRNA is broadly distributed in previtellogenic ovarioles. E93 homozygous mutant females of T. domestica exhibit severe fecundity deficiency due to impaired previtellogenic development of the ovarian follicles, likely because E93 induces the expression of genes involved in ECM (extracellular matrix)-receptor interactions during previtellogenesis. Moreover, we reveal that in the hemimetabolous cockroach Blattella germanica, E93 similarly promotes previtellogenic ovarian development. In addition, E93 is also essential for vitellogenesis that is necessary to guarantee ovarian maturation and promotes the vitellogenesis-previtellogenesis switch in the fat body of adult female cockroaches. Our findings deepen the understanding of the roles of E93 in controlling reproduction in insects, and of E93 expression and functional evolution, which are proposed to have made crucial contributions to the origin of insect metamorphosis.


Assuntos
Metamorfose Biológica , Ovário , Reprodução , Animais , Feminino , Reprodução/genética , Metamorfose Biológica/genética , Ovário/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Vitelogênese/genética , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética
2.
Plant Cell ; 36(5): 1637-1654, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38114096

RESUMO

MicroRNAs (miRNAs) are a class of nonprotein-coding short transcripts that provide a layer of post-transcriptional regulation essential to many plant biological processes. MiR858, which targets the transcripts of MYB transcription factors, can affect a range of secondary metabolic processes. Although miR858 and its 187-nt precursor have been well studied in Arabidopsis (Arabidopsis thaliana), a systematic investigation of miR858 precursors and their functions across plant species is lacking due to a problem in identifying the transcripts that generate this subclass. By re-evaluating the transcript of miR858 and relaxing the length cut-off for identifying hairpins, we found in kiwifruit (Actinidia chinensis) that miR858 has long-loop hairpins (1,100 to 2,100 nt), whose intervening sequences between miRNA generating complementary sites were longer than all previously reported miRNA hairpins. Importantly, these precursors of miR858 containing long-loop hairpins (termed MIR858L) are widespread in seed plants including Arabidopsis, varying between 350 and 5,500 nt. Moreover, we showed that MIR858L has a greater impact on proanthocyanidin and flavonol levels in both Arabidopsis and kiwifruit. We suggest that an active MIR858L-MYB regulatory module appeared in the transition of early land plants to large upright flowering plants, making a key contribution to plant secondary metabolism.


Assuntos
Actinidia , Arabidopsis , Regulação da Expressão Gênica de Plantas , MicroRNAs , RNA de Plantas , MicroRNAs/genética , MicroRNAs/metabolismo , Actinidia/genética , Actinidia/metabolismo , Arabidopsis/genética , RNA de Plantas/genética , RNA de Plantas/metabolismo , Sementes/genética , Sementes/metabolismo , Sequência de Bases
3.
Nat Methods ; 19(1): 119-128, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34949809

RESUMO

Due to advances in automated image acquisition and analysis, whole-brain connectomes with 100,000 or more neurons are on the horizon. Proofreading of whole-brain automated reconstructions will require many person-years of effort, due to the huge volumes of data involved. Here we present FlyWire, an online community for proofreading neural circuits in a Drosophila melanogaster brain and explain how its computational and social structures are organized to scale up to whole-brain connectomics. Browser-based three-dimensional interactive segmentation by collaborative editing of a spatially chunked supervoxel graph makes it possible to distribute proofreading to individuals located virtually anywhere in the world. Information in the edit history is programmatically accessible for a variety of uses such as estimating proofreading accuracy or building incentive systems. An open community accelerates proofreading by recruiting more participants and accelerates scientific discovery by requiring information sharing. We demonstrate how FlyWire enables circuit analysis by reconstructing and analyzing the connectome of mechanosensory neurons.


Assuntos
Encéfalo/fisiologia , Conectoma/métodos , Drosophila melanogaster/fisiologia , Imageamento Tridimensional/métodos , Software , Animais , Encéfalo/citologia , Encéfalo/diagnóstico por imagem , Gráficos por Computador , Visualização de Dados , Drosophila melanogaster/citologia , Neurônios/citologia , Neurônios/fisiologia
4.
Plant Cell Physiol ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38988198

RESUMO

As a model plant for bryophytes, Marchantia polymorpha offers insights into the role of RNA silencing in aiding early land plants navigate the challenges posed by high-temperature environments. Genomic analysis revealed unique ARGONAUTE1 ortholog gene (MpAGO1) in M. polymorpha that is regulated by two species-specific microRNAs (miRNAs), miR11707.1 and miR11707.2. Comparative studies of small RNA profiles from M. polymorpha cellular and MpAGO1 immunoprecipitation (MpAGO1-IP) profiles at various temperatures, along with analyses of Arabidopsis AGO1 (AtAGO1), revealed that MpAGO1 has a low-selectivity for a diverse range of small RNA species than AtAGO1. Protein structural comparisons revealed no discernible differences in the MID domains of MpAGO1 and AtAGO1, suggesting the complexity of miRNA species specificity and necessitating further exploration. Small RNA profiling and size exclusion chromatography have pinpointed a subset of M. polymorpha miRNAs, notably miR11707, that remain in free form within the cell at 22°C but are loaded into MpAGO1 at 28°C to engage in RNA silencing. Investigations into the mir11707 gene editing (mir11707ge) mutants provided evidence of the regulation of miR11707 in MpAGO1. Notably, while MpAGO1 mRNA expression decreases at 28°C, the stability of the MpAGO1 protein and its associated miRNAs is essential for enhancing the RISC activity, revealing the importance of RNA silencing in enabling M. polymorpha to survive thermal stress. This study advances our understanding of RNA silencing in bryophytes and provides groundbreaking insights into the evolutionary resilience of land plants to climatic adversities.

5.
Plant Cell Physiol ; 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38545690

RESUMO

The miR390-derived TAS3 trans-acting short-interfering RNAs (tasiRNAs) module represents a conserved RNA silencing pathway in the plant kingdom; however, its characterization in the bryophyte Marchantia polymorpha is limited. This study elucidated that MpDCL4 processes MpTAS3 double-stranded RNA (dsRNA) to generate tasiRNAs, primarily from the 5'- and 3'-ends of dsRNA. Notably, we discovered a novel tasiRNA, tasi78A, can negatively regulate a cytochrome P450 gene, MpCYP78A101. Additionally, tasi78A was abundant in MpAGO1, and transient expression assays underscored the role of tasi78A in repressing MpCYP78A101. A microRNA, miR11700, also regulates MpCYP78A101 expression. This coordinate regulation suggests a role in modulating auxin signaling at apical notches of gemma, influencing the growth and sexual organ development of M. polymorpha and emphasizing the significance of RNA silencing in MpCYP78A101 regulation. However, phylogenetic analysis identified another paralog of the CYP78 family, Mp1g14150, which may have a redundant role with MpCYP78A101, explaining the absence of noticeable morphological changes in loss-of-function plants. Taken together, our findings provide new insights into the combined regulatory roles of miR390/MpTAS3/miR11700 in controlling MpCYP78A101 and expand our knowledge about the biogenesis and regulation of tasiRNAs in M. polymorpha.

6.
Mult Scler ; 30(1): 7-15, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37982449

RESUMO

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is a group of inflammatory diseases affecting the central nervous system, characterized by optic neuritis and myelitis. The complex nature of NMOSD and varied patient response necessitates personalized treatment and efficient patient stratification strategies. OBJECTIVE: To provide a comprehensive review of recent advances in clinical and biomarker research related to aquaporin-4 (AQP4)-immunoglobulin G (IgG)-seropositive NMOSD prognosis and identify key areas for future research. METHODS: A comprehensive review and synthesis of recent literature were conducted, focusing on demographic factors and laboratory investigations. RESULTS: Demographic factors, such as age, ethnicity, and sex, influence NMOSD prognosis. Key biomarkers for NMOSD prognosis include homocysteine, antinuclear antibodies, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, thyroid hormone levels, neurofilament light chain levels, and serum glial fibrillary acidic protein might also predict NMOSD attack prognosis. CONCLUSION: Further investigation is required to understand sex-related disparities and biomarker inconsistencies. Identification and understanding of these factors can aid in the development of personalized therapeutic strategies, thereby improving outcomes for NMOSD patients. Future studies should focus on unifying research design for consistent results.


Assuntos
Neuromielite Óptica , Humanos , Imunoglobulina G , Prognóstico , Aquaporina 4 , Biomarcadores , Autoanticorpos , Demografia
7.
Org Biomol Chem ; 22(25): 5159-5169, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38860854

RESUMO

Indoles, indolines and hydronaphthylamines are ubiquitous structural motifs in natural products, pharmaceuticals, and biologically active molecules. In this paper, we report the synthesis of aminodihydronaphthyl-substituted indoles and indolines via a Ru-catalyzed carbamoyl-directed C-H functionalization of indoles and indolines with 7-azabenzonorbornadienes. In the presence of Cu(OAc)2 and AgSbF6, [Ru(p-cymene)Cl2]2 catalyzes the reaction of 1-carbamoylindoles with 7-azabenzonorbornadienes to produce 2-(1-amino-1,2-dihydronaphthalen-2-yl)indoles. Under the same conditions, the reaction of 1-carbamoylindolines with 7-azabenzonorbornadienes affords 7-(1-amino-1,2-dihydronaphthalen-2-yl)indolines. In both cases, the reactions yield cis-configured products.

8.
Nanotechnology ; 35(26)2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38527361

RESUMO

Conjugated polymer-based organic/inorganic hybrid materials become the current research frontier and show great potential to integrate flexible polymers and rigid solid materials, which have been widely used in the field of various flexible electronics and optical devices. In this study, based on the multiple vapor phase infiltration (VPI) process, various precursor molecules (diethylzinc DEZ, trimethylaluminum TMA, H2O) are applied for thein situmodification of PBTTT-C14 films. The conductivity of the PBTTT-C14/Al2O3:ZnO (AZO) film is significantly enhanced, and the maximum value of conductivity is 1.16 S cm-1, which is eight orders of magnitude higher than the undoped PBTTT-C14 thin film. Here, the change of morphologies and crystalline states are analyzed via SEM, AFM, and XRD. And the chemical changes during the VPI process of PBTTT-C14 are characterized through Raman, XPS, and UV-vis. During the AZO VPI process, the formation of new ZnS matrix in the polymer subsurface can generate new additional electron conduction pathways through the crosslinking of polymer chains with inorganic materials, and the addition of Al2O3can bring about the increase of average grain size of ZnO crystals, which is also benefit to the conductivity increase of PBTTT-C14 thin film. Generally, the synergistic effect between the inorganic and polymer constituents results in the significantly enhancement of the conductivity of PBTTT-C14/AZO thin films.

9.
Bioorg Med Chem ; 100: 117631, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38330848

RESUMO

Acute myeloid leukemia (AML) is the most common type of blood cancer and has been strongly correlated with the overexpression of Fms-like tyrosine kinase 3 (FLT3), a member of the class III receptor tyrosine kinase family. With the emergence of FLT3 internal tandem duplication alteration (ITD) and tyrosine kinase domain (TKD) mutations, the development of FLT3 small molecule inhibitors has become an effective medicinal chemistry strategy for AML. Herein, we have designed and synthesized two series of 1H-pyrrolo[2,3-b]pyridine derivatives CM1-CM24, as FLT3 inhibitors based on F14, which we previously reported, that can target the hydrophobic FLT3 back pocket. Among these derivates, CM5 showed significant inhibition of FLT3 and FLT3-ITD, with inhibitory percentages of 57.72 % and 53.77 % respectively at the concentration of 1 µΜ. Furthermore, CM5 demonstrated potent inhibition against FLT3-dependent human AML cell lines MOLM-13 and MV4-11 (both harboring FLT3-ITD mutant), with IC50 values of 0.75 µM and 0.64 µM respectively. In our cellular mechanistic studies, CM5 also effectively induces apoptosis by arresting cell cycle progression in the G0/G1 phase. In addition, the amide and urea linker function were discussed in detail based on computational simulations studies. CM5 will serve as a novel lead compound for further structural modification and development of FLT3 inhibitors specifically targeting AML with FLT3-ITD mutations.


Assuntos
Leucemia Mieloide Aguda , Tirosina Quinase 3 Semelhante a fms , Humanos , Apoptose , Linhagem Celular Tumoral , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Mutação , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Piridinas/farmacologia
10.
Neuroradiology ; 66(3): 409-416, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38191867

RESUMO

PURPOSE: Endovascular reconstruction has emerged as a viable alternative for carotid artery dissections (CADs) that are unresponsive to antithrombotic therapy. However, high cervical and long-segment CADs pose challenges during endovascular treatment due to their distal location and tortuous anatomy. We presented our experiences using endovascular reconstruction with the Leo plus stent for this type of CAD. METHODS: We conducted a retrospective review of patients with high cervical and long-segment CADs treated using the Leo plus stent. We analyzed patient demographics, clinical presentations, procedural features, complications, and follow-up outcomes. RESULTS: A total of 17 patients (mean age, 48.1 years) with 17 CADs were identified. Seven of these dissections were accompanied by pseudoaneurysm. The mean length of the dissection was 5.7 cm, and the mean degree of stenosis was 92.3%. A single Leo plus stent was deployed in 15 patients, while another Wallstent carotid stent was used in 2 cases. All stents were successfully positioned in their intended sites. The average degree of residual stenosis was 22.2%. There were no perioperative complications. With a median follow-up duration of 29 months, no ischemic stroke events occurred. All but one Leo plus stent remained patent during follow-up, and all 7 pseudoaneurysms had disappeared at the last radiological assessment. CONCLUSION: Our experience in treating high cervical and long-segment CADs with the Leo plus stent demonstrates that this approach is practical, safe, and effective, as evidenced by long-term observations. The Leo Plus stent appears to be a suitable option for managing this type of CAD.


Assuntos
Dissecção Aórtica , Dissecação da Artéria Carótida Interna , Procedimentos Endovasculares , Humanos , Pessoa de Meia-Idade , Dissecação da Artéria Carótida Interna/diagnóstico por imagem , Dissecação da Artéria Carótida Interna/cirurgia , Constrição Patológica/complicações , Resultado do Tratamento , Stents , Estudos Retrospectivos , Artérias Carótidas
11.
Mol Med ; 29(1): 86, 2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-37400752

RESUMO

BACKGROUND: Osteoarthritis (OA) is a degenerative joint disease with lacking effective prevention targets. A disintegrin and metalloproteinase with thrombospondin motifs 12 (ADAMTS12) is a member of the ADAMTS family and is upregulated in OA pathologic tissues with no fully understood molecular mechanisms. METHODS: The anterior cruciate ligament transection (ACL-T) method was used to establish rat OA models, and interleukin-1 beta (IL-1ß) was administered to induce rat chondrocyte inflammation. Cartilage damage was analyzed via hematoxylin-eosin, Periodic Acid-Schiff, safranin O-fast green, Osteoarthritis Research Society International score, and micro-computed tomography assays. Chondrocyte apoptosis was detected by flow cytometry and TdT dUTP nick-end labeling. Signal transducer and activator of transcription 1 (STAT1), ADAMTS12, and methyltransferase-like 3 (METTL3) levels were detected by immunohistochemistry, quantitative polymerase chain reaction (qPCR), western blot, or immunofluorescence assay. The binding ability was confirmed by chromatin immunoprecipitation-qPCR, electromobility shift assay, dual-luciferase reporter, or RNA immunoprecipitation (RIP) assay. The methylation level of STAT1 was analyzed by MeRIP-qPCR assay. STAT1 stability was investigated by actinomycin D assay. RESULTS: The STAT1 and ADAMTS12 expressions were significantly increased in the human and rat samples of cartilage injury, as well as in IL-1ß-treated rat chondrocytes. STAT1 is bound to the promoter region of ADAMTS12 to activate its transcription. METTL3/ Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) mediated N6-methyladenosine modification of STAT1 promoted STAT1 mRNA stability, resulting in increased expression. ADAMTS12 expression was reduced and the IL-1ß-induced inflammatory chondrocyte injury was attenuated by silencing METTL3. Additionally, knocking down METTL3 in ACL-T-produced OA rats reduced ADAMTS12 expression in their cartilage tissues, thereby alleviating cartilage damage. CONCLUSION: METTL3/IGF2BP2 axis increases STAT1 stability and expression to promote OA progression by up-regulating ADAMTS12 expression.


Assuntos
MicroRNAs , Osteoartrite , Ratos , Humanos , Animais , Osteoartrite/metabolismo , Microtomografia por Raio-X , Células Cultivadas , Cartilagem/metabolismo , Condrócitos/metabolismo , Interleucina-1beta/metabolismo , MicroRNAs/metabolismo , Apoptose , Proteínas ADAMTS/genética , Proteínas ADAMTS/metabolismo , Metiltransferases/metabolismo , Proteínas de Ligação a RNA/metabolismo
12.
Anal Chem ; 95(28): 10512-10521, 2023 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-37406615

RESUMO

Direct-infusion Fourier transform ion cyclotron resonance mass spectrometry (DI-FTICR MS) shows great promise for metabolomic analysis due to ultrahigh mass accuracy and resolution. However, most of the DI-FTICR MS approaches focused on high-throughput metabolomics analysis at the expense of sensitivity and resolution and the potential for metabolome characterization has not been fully explored. Here, we proposed a novel deep characterization approach of serum metabolome using a segment-optimized spectral-stitching DI-FTICR MS method integrated with high-confidence and database-independent formula assignments. With varied acquisition parameters for each segment, a highly efficient acquisition was achieved for the whole mass range with sub-ppm mass accuracy. In a pooled human serum sample, thousands of features were assigned with unambiguous formulas and possible candidates based on highly accurate mass measurements. Furthermore, a reaction network was used to select confidently unique formulas from possible candidates, which was constructed by unambiguous formulas and possible candidates connected by the formula differences resulting from biochemical and MS transformation. Compared with full-range and conventional segment acquisition, 8- and 1.2-fold increases in observed features were achieved, respectively. Assignment accuracy was 93-94% for both a standard mixture containing 190 metabolites and a spiked serum sample with the root mean square mass error of 0.15-0.16 ppm. In total, 3534 unequivocal neutral molecular formulas were assigned in the pooled serum sample, 35% of which are contained in the HMDB. This method offers great enhancement in the deep characterization of serum metabolome by DI-FTICR MS.


Assuntos
Ciclotrons , Metaboloma , Humanos , Análise de Fourier , Espectrometria de Massas/métodos , Metabolômica
13.
Plant Biotechnol J ; 21(10): 1966-1977, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37392004

RESUMO

Dissecting the genetic basis of complex traits such as dynamic growth and yield potential is a major challenge in crops. Monitoring the growth throughout growing season in a large wheat population to uncover the temporal genetic controls for plant growth and yield-related traits has so far not been explored. In this study, a diverse wheat panel composed of 288 lines was monitored by a non-invasive and high-throughput phenotyping platform to collect growth traits from seedling to grain filling stage and their relationship with yield-related traits was further explored. Whole genome re-sequencing of the panel provided 12.64 million markers for a high-resolution genome-wide association analysis using 190 image-based traits and 17 agronomic traits. A total of 8327 marker-trait associations were detected and clustered into 1605 quantitative trait loci (QTLs) including a number of known genes or QTLs. We identified 277 pleiotropic QTLs controlling multiple traits at different growth stages which revealed temporal dynamics of QTLs action on plant development and yield production in wheat. A candidate gene related to plant growth that was detected by image traits was further validated. Particularly, our study demonstrated that the yield-related traits are largely predictable using models developed based on i-traits and provide possibility for high-throughput early selection, thus to accelerate breeding process. Our study explored the genetic architecture of growth and yield-related traits by combining high-throughput phenotyping and genotyping, which further unravelled the complex and stage-specific contributions of genetic loci to optimize growth and yield in wheat.


Assuntos
Estudo de Associação Genômica Ampla , Triticum , Triticum/genética , Melhoramento Vegetal , Fenótipo , Locos de Características Quantitativas/genética
14.
Opt Express ; 31(5): 8884-8896, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36859994

RESUMO

Frequency selective surfaces (FSSs), modern artificial materials, show great potential in engineering applications due to their excellent frequency selection capabilities. In this paper, we introduce a flexible strain sensor based on FSS reflection characteristics, which can be well conformally attached to the surface of an object and bear mechanical deformation from a certain load. When the FSS structure changes, the original working frequency will be shifted. By measuring the difference in electromagnetic performance, the strain degree of the object can be monitored in real-time. In this study, we designed an FSS sensor with a working frequency of 31.4 GHz and amplitude that reaches -35 dB that exhibits favorable resonance properties in the Ka-band. The quality factor of FSS is 16.2, which indicates that the sensor has excellent sensing performance. The sensor was applied in the strain detection of a rocket engine case through statics and electromagnetic simulations. The analysis showed that the working frequency of the sensor shifted by approximately 200 MHz for 1.64% radial expansion of the engine case and the frequency shift exhibits an excellent linear relationship with the deformation in diverse loads, so it can be used for accurate strain detection of the case. Based on experiments, we carried out the uniaxial tensile test of the FSS sensor in this study. The sensor's sensitivity was 1.28 GHz/mm when the FSS was stretched by 0-3 mm in the test. Therefore, the FSS sensor has high sensitivity and strong mechanical properties, which verifies the practical value of the FSS structure designed in this paper. It has a broad development space in this field.

15.
Glob Chang Biol ; 29(4): 1178-1187, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36371668

RESUMO

Multiple lines of existing evidence suggest that increasing CO2 emission from soils in response to rising temperature could accelerate global warming. However, in experimental studies, the initial positive response of soil heterotrophic respiration (RH ) to warming often weakens over time (referred to apparent thermal acclimation). If the decreased RH is driven by thermal adaptation of soil microbial community, the potential for soil carbon (C) losses would be reduced substantially. In the meanwhile, the response could equally be caused by substrate depletion, and would then reflect the gradual loss of soil C. To address uncertainties regarding the causes of apparent thermal acclimation, we carried out sterilization and inoculation experiments using the soil samples from an alpine meadow with 6 years of warming and nitrogen (N) addition. We demonstrate that substrate depletion, rather than microbial adaptation, determined the response of RH to long-term warming. Furthermore, N addition appeared to alleviate the apparent acclimation of RH to warming. Our study provides strong empirical support for substrate availability being the cause of the apparent acclimation of soil microbial respiration to temperature. Thus, these mechanistic insights could facilitate efforts of biogeochemical modeling to accurately project soil C stocks in the future climate.


Assuntos
Microbiologia do Solo , Solo , Processos Heterotróficos , Aquecimento Global , Aclimatação , Temperatura , Carbono , Respiração
16.
Glob Chang Biol ; 29(12): 3476-3488, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36931867

RESUMO

Root exudates are an important pathway for plant-microbial interactions and are highly sensitive to climate change. However, how extreme drought affects root exudates and the main components, as well as species-specific differences in response magnitude and direction, are poorly understood. In this study, root exudation rates of total carbon (C) and its components (e.g., sugar, organic acid, and amino acid) were measured under the control and extreme drought treatments (i.e., 70% throughfall reduction) by in situ collection of four tree species with different growth rates in a subtropical forest. We also quantified soil properties, root morphological traits, and mycorrhizal infection rates to examine the driving factors underlying variations in root exudation. Our results showed that extreme drought significantly decreased root exudation rates of total C, sugar, and amino acid by 17.8%, 30.8%, and 35.0%, respectively, but increased root exudation rate of organic acid by 38.6%, which were largely associated with drought-induced changes in tree growth rates, root morphological traits, and mycorrhizal infection rates. Specifically, trees with relatively high growth rates were more responsive to drought for root exudation rates compared with those with relatively low growth rates, which were closely related to root morphological traits and mycorrhizal infection rates. These findings highlight the importance of plant growth strategy in mediating drought-induced changes in root exudation rates. The coordinations among root exudation rates, root morphological traits, and mycorrhizal symbioses in response to drought could be incorporated into land surface models to improve the prediction of climate change impacts on rhizosphere C dynamics in forest ecosystems.


Assuntos
Ecossistema , Micorrizas , Raízes de Plantas/metabolismo , Secas , Florestas , Micorrizas/metabolismo , Árvores , Exsudatos e Transudatos/metabolismo , Compostos Orgânicos/análise , Aminoácidos/análise , Aminoácidos/metabolismo , Solo/química , Açúcares/análise , Açúcares/metabolismo , Exsudatos de Plantas/análise , Exsudatos de Plantas/metabolismo
17.
Phys Rev Lett ; 131(8): 086501, 2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37683154

RESUMO

Strong electron correlation under two-dimensional limit is intensely studied in the transition metal dichalcogenides monolayers, mostly within their charge density wave (CDW) states that host a star of David period. Here, by using scanning tunneling microscopy and spectroscopy and density functional theory calculations with on-site Hubbard corrections, we study the VTe_{2} monolayer with a different 2sqrt[3]×2sqrt[3] CDW period. We find that the dimerization of neighboring Te-Te and V-V atoms occurs during the CDW transition, and that the strong correlation effect opens a Mott-like full gap at Fermi energy (E_{F}). We further demonstrate that such a Mott phenomenon is ascribed to the combination of the CDW transition and on-site Coulomb interactions. Our work provides a new platform for exploring Mott physics in 2D materials.

18.
Phys Rev Lett ; 131(25): 256002, 2023 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-38181352

RESUMO

The Fe_{4}Se_{5} with a sqrt[5]×sqrt[5] Fe vacancy order is suggested to be a Mott insulator and the parent state of bulk FeSe superconductor. The iron vacancy ordered state has been considered as a Mott insulator and the parent compound of bulk FeSe-based superconductors. However, for the superconducting FeSe/SrTiO_{3} monolayer (FeSe/STO) with an interface-enhanced high transition temperature (T_{c}), the electronic evolution from its Fe vacancy ordered parent phase to the superconducting state, has not been explored due to the challenge to realize an Fe vacancy order in the FeSe/STO monolayer, even though important to the understanding of superconductivity mechanism. In this study, we developed a new method to generate Fe vacancies within the FeSe/STO monolayer in a tunable fashion, with the assistance of atomic hydrogen. As a consequence, an insulating sqrt[5]×sqrt[5] Fe vacancy ordered monolayer is realized as the parent state. By using scanning tunneling microscopy and scanning tunneling spectroscopy, the spectral evolution from superconductivity to insulator is fully characterized. Surprisingly, a prominent spectral weight transfer occurs, thus implying a strong electron correlation effect. Moreover, the Fe vacancy induced insulating gap exhibits no Mott gap-like features. This work provides new insights in understanding the high-T_{c} superconductivity in FeSe/STO monolayer.

19.
Inorg Chem ; 62(48): 19690-19697, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-38044827

RESUMO

Owing to the exterior self-trapped excitons (STEs) with adjustable fluorescence beams, low-dimensional ns2-metal halides have recently received considerable attention in solid-state light-emitting applications. However, the photoluminescence (PL) mechanism in metal halides remains a major challenge in achieving high efficiency and controllable PL properties because the excited-state energy of ns2 conformational ions varies inhomogeneously with their coordination environments. Here, a novel zero-dimensional (0D) lead-free bismuth-based Rb3BiCl6·0.5H2O crystal was reported as a pristine crystal to modulate the optical properties. By doping Sb3+ ions with 5s2 electrons into Rb3BiCl6·0.5H2O crystals, bright orange emission at room temperature was obtained with a photoluminescence quantum yield of 39.7%. Optical characterizations and theoretical studies show that the Sb3+ doping can suppress the strong exciton-phonon coupling, optimize the electronic energy band structure, improve the thermal activation energy, soften the structural lattice of the host crystals, deepen the STE states, and ultimately lead to strong photoluminescence. This work manifests a fruitful manipulation in ripening bismuth-based halides with high-efficiency PL properties, and the PL enhancement mechanisms will guide future research in the exploration of emerging luminescent materials.

20.
Nanotechnology ; 35(11)2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38081078

RESUMO

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis and lacks effective therapeutic targets. The use of gambogic acid (GA), a class of active ingredients in traditional Chinese medicine with anti-tumour potential, is limited in tumour therapy owing to its drawbacks and unclear organ toxicity. In this study, we used the pH-responsive amphiphilic block copolymer, PEOz-PCL, to create nanodrugs for GA delivery to MDA-MB-231 cells. The pH-responsive GA-loaded micelles were prepared through nanoprecipitation with a more homogeneous size. The average particle size was 42.29 ± 1.74 nm, and the zeta potential value was 9.88 ± 0.17 mV. The encapsulation rate was 85.06%, and the drug loading rate was 10.63%. The process was reproducible, and sustained release reached 80% in 96 h at acid pH 5.0. Furthermore, cellular tests using CCK-8, TUNEL, and flow cytometry revealed that pH-responsive GA-loaded micelles killed MDA-MB-231 cells more effectively and had much higher activity and targeting compared with free drugs. Metabolomic analysis of the changes in differential metabolites revealed that pH-responsive GA-loaded micelles may inhibit TNBC cells by causing amino acid anabolism, nucleotide metabolism, and glucose metabolism, as well as by affecting their energy sources. The study outcomes will help understand the mechanism of action and the therapeutic efficacy of pH-responsive GA-loaded micellesin vivo.


Assuntos
Neoplasias de Mama Triplo Negativas , Xantonas , Humanos , Micelas , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Xantonas/farmacologia , Xantonas/química , Linhagem Celular Tumoral , Concentração de Íons de Hidrogênio , Portadores de Fármacos/química
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