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1.
Cell ; 177(7): 1842-1857.e21, 2019 06 13.
Artículo en Inglés | MEDLINE | ID: mdl-31155235

RESUMEN

Mutational processes giving rise to lung adenocarcinomas (LADCs) in non-smokers remain elusive. We analyzed 138 LADC whole genomes, including 83 cases with minimal contribution of smoking-associated mutational signature. Genomic rearrangements were not correlated with smoking-associated mutations and frequently served as driver events of smoking-signature-low LADCs. Complex genomic rearrangements, including chromothripsis and chromoplexy, generated 74% of known fusion oncogenes, including EML4-ALK, CD74-ROS1, and KIF5B-RET. Unlike other collateral rearrangements, these fusion-oncogene-associated rearrangements were frequently copy-number-balanced, representing a genomic signature of early oncogenesis. Analysis of mutation timing revealed that fusions and point mutations of canonical oncogenes were often acquired in the early decades of life. During a long latency, cancer-related genes were disrupted or amplified by complex rearrangements. The genomic landscape was different between subgroups-EGFR-mutant LADCs had frequent whole-genome duplications with p53 mutations, whereas fusion-oncogene-driven LADCs had frequent SETD2 mutations. Our study highlights LADC oncogenesis driven by endogenous mutational processes.


Asunto(s)
Adenocarcinoma del Pulmón , Reordenamiento Génico , Neoplasias Pulmonares , Mutación , Proteínas de Fusión Oncogénica , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/metabolismo , Adenocarcinoma del Pulmón/patología , Femenino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Masculino , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo
2.
Cell ; 177(6): 1600-1618.e17, 2019 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-31150625

RESUMEN

Autism spectrum disorder (ASD) manifests as alterations in complex human behaviors including social communication and stereotypies. In addition to genetic risks, the gut microbiome differs between typically developing (TD) and ASD individuals, though it remains unclear whether the microbiome contributes to symptoms. We transplanted gut microbiota from human donors with ASD or TD controls into germ-free mice and reveal that colonization with ASD microbiota is sufficient to induce hallmark autistic behaviors. The brains of mice colonized with ASD microbiota display alternative splicing of ASD-relevant genes. Microbiome and metabolome profiles of mice harboring human microbiota predict that specific bacterial taxa and their metabolites modulate ASD behaviors. Indeed, treatment of an ASD mouse model with candidate microbial metabolites improves behavioral abnormalities and modulates neuronal excitability in the brain. We propose that the gut microbiota regulates behaviors in mice via production of neuroactive metabolites, suggesting that gut-brain connections contribute to the pathophysiology of ASD.


Asunto(s)
Trastorno del Espectro Autista/microbiología , Síntomas Conductuales/microbiología , Microbioma Gastrointestinal/fisiología , Animales , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/fisiopatología , Bacterias , Conducta Animal/fisiología , Encéfalo/metabolismo , Modelos Animales de Enfermedad , Humanos , Ratones , Microbiota , Factores de Riesgo
3.
Cell ; 175(7): 1744-1755.e15, 2018 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-30503208

RESUMEN

Tumor-infiltrating CD8 T cells were found to frequently express the inhibitory receptor NKG2A, particularly in immune-reactive environments and after therapeutic cancer vaccination. High-dimensional cluster analysis demonstrated that NKG2A marks a unique immune effector subset preferentially co-expressing the tissue-resident CD103 molecule, but not immune checkpoint inhibitors. To examine whether NKG2A represented an adaptive resistance mechanism to cancer vaccination, we blocked the receptor with an antibody and knocked out its ligand Qa-1b, the conserved ortholog of HLA-E, in four mouse tumor models. The impact of therapeutic vaccines was greatly potentiated by disruption of the NKG2A/Qa-1b axis even in a PD-1 refractory mouse model. NKG2A blockade therapy operated through CD8 T cells, but not NK cells. These findings indicate that NKG2A-blocking antibodies might improve clinical responses to therapeutic cancer vaccines.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Vacunas contra el Cáncer , Inmunidad Celular , Subfamília C de Receptores Similares a Lectina de Células NK , Proteínas de Neoplasias , Neoplasias Experimentales , Vacunación , Animales , Anticuerpos Antineoplásicos/inmunología , Antígenos CD/inmunología , Linfocitos T CD8-positivos/patología , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/farmacología , Línea Celular Tumoral , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Cadenas alfa de Integrinas/inmunología , Ratones , Subfamília C de Receptores Similares a Lectina de Células NK/antagonistas & inhibidores , Subfamília C de Receptores Similares a Lectina de Células NK/inmunología , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/inmunología , Neoplasias Experimentales/inmunología , Neoplasias Experimentales/patología , Neoplasias Experimentales/terapia , Antígenos HLA-E
4.
Cell ; 173(2): 355-370.e14, 2018 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-29625052

RESUMEN

We conducted the largest investigation of predisposition variants in cancer to date, discovering 853 pathogenic or likely pathogenic variants in 8% of 10,389 cases from 33 cancer types. Twenty-one genes showed single or cross-cancer associations, including novel associations of SDHA in melanoma and PALB2 in stomach adenocarcinoma. The 659 predisposition variants and 18 additional large deletions in tumor suppressors, including ATM, BRCA1, and NF1, showed low gene expression and frequent (43%) loss of heterozygosity or biallelic two-hit events. We also discovered 33 such variants in oncogenes, including missenses in MET, RET, and PTPN11 associated with high gene expression. We nominated 47 additional predisposition variants from prioritized VUSs supported by multiple evidences involving case-control frequency, loss of heterozygosity, expression effect, and co-localization with mutations and modified residues. Our integrative approach links rare predisposition variants to functional consequences, informing future guidelines of variant classification and germline genetic testing in cancer.


Asunto(s)
Células Germinativas/metabolismo , Neoplasias/patología , Variaciones en el Número de Copia de ADN , Bases de Datos Genéticas , Eliminación de Gen , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Células Germinativas/citología , Mutación de Línea Germinal , Humanos , Pérdida de Heterocigocidad/genética , Mutación Missense , Neoplasias/genética , Polimorfismo de Nucleótido Simple , Proteínas Proto-Oncogénicas c-met/genética , Proteínas Proto-Oncogénicas c-ret/genética , Proteínas Supresoras de Tumor/genética
5.
Nat Immunol ; 19(6): 583-593, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29713015

RESUMEN

The incidence of atherosclerosis is higher among patients with systemic lupus erythematosus (SLE); however, the mechanism by which an atherogenic environment affects autoimmunity remains unclear. We found that reconstitution of atherosclerosis-prone Apoe-/- and Ldlr-/- mice with bone marrow from lupus-prone BXD2 mice resulted in increased autoantibody production and glomerulonephritis. This enhanced disease was associated with an increase in CXCR3+ follicular helper T cells (TFH cells). TFH cells isolated from Apoe-/- mice had higher expression of genes associated with inflammatory responses and SLE and were more potent in inducing production of the immunoglobulin IgG2c. Mechanistically, the atherogenic environment induced the cytokine IL-27 from dendritic cells in a Toll-like receptor 4 (TLR4)-dependent manner, which in turn triggered the differentiation of CXCR3+ TFH cells while inhibiting the differentiation of follicular regulatory T cells. Blockade of IL-27 signals diminished the increased TFH cell responses in atherogenic mice. Thus, atherogenic dyslipidemia augments autoimmune TFH cell responses and subsequent IgG2c production in a TLR4- and IL-27-dependent manner.


Asunto(s)
Aterosclerosis/inmunología , Dislipidemias/inmunología , Interleucinas/inmunología , Lupus Eritematoso Sistémico/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Autoinmunidad/inmunología , Diferenciación Celular/inmunología , Células Dendríticas/inmunología , Ratones , Ratones Noqueados , Receptor Toll-Like 4/inmunología
6.
Nat Immunol ; 19(9): 1036, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29921921

RESUMEN

In the version of this article initially published, the third label along the horizontal axis of Fig. 4b (Il13a) and the middle label above each plot in Fig. 6k (Stat-/-) were incorrect, and the hash marks along the horizontal axis for Fig. 6i were spaced incorrectly. Also, the statistical results in the citation for Supplementary Fig. 5a (*P < 0.05, **P < 0.01 and ***P < 0.001 (unpaired Student's t-test)) in the fifth subsection of Results were incorrect. The correct label for Fig. 4b is Il23a and for Fig. 6k is Stat1-/-, and the right hash mark along the horizontal axis for Fig. 6i should be beneath the data points at right. The correct citation of the statistical results is as follows: "(P < 0.05 and P < 0.01 (unpaired Student's t-test); Supplementary Fig. 5a)." The errors have been corrected in the HTML and PDF version of the article.

7.
Immunity ; 54(1): 44-52.e3, 2021 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-33338412

RESUMEN

Memory T cell responses have been demonstrated in COVID-19 convalescents, but ex vivo phenotypes of SARS-CoV-2-specific T cells have been unclear. We detected SARS-CoV-2-specific CD8+ T cells by MHC class I multimer staining and examined their phenotypes and functions in acute and convalescent COVID-19. Multimer+ cells exhibited early differentiated effector-memory phenotypes in the early convalescent phase. The frequency of stem-like memory cells was increased among multimer+ cells in the late convalescent phase. Cytokine secretion assays combined with MHC class I multimer staining revealed that the proportion of interferon-γ (IFN-γ)-producing cells was significantly lower among SARS-CoV-2-specific CD8+ T cells than those specific to influenza A virus. Importantly, the proportion of IFN-γ-producing cells was higher in PD-1+ cells than PD-1- cells among multimer+ cells, indicating that PD-1-expressing, SARS-CoV-2-specific CD8+ T cells are not exhausted, but functional. Our current findings provide information for understanding of SARS-CoV-2-specific CD8+ T cells elicited by infection or vaccination.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , COVID-19/inmunología , Receptor de Muerte Celular Programada 1/metabolismo , SARS-CoV-2/inmunología , Reacción de Fase Aguda/inmunología , Reacción de Fase Aguda/virología , COVID-19/patología , COVID-19/virología , Convalecencia , Epítopos de Linfocito T , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Memoria Inmunológica , Inmunofenotipificación , Interferón gamma/metabolismo , Activación de Linfocitos , Carga Viral
8.
Cell ; 162(4): 780-94, 2015 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-26276632

RESUMEN

The transcriptional co-activators YAP and TAZ are key regulators of organ size and tissue homeostasis, and their dysregulation contributes to human cancer. Here, we discover YAP/TAZ as bona fide downstream effectors of the alternative Wnt signaling pathway. Wnt5a/b and Wnt3a induce YAP/TAZ activation independent of canonical Wnt/ß-catenin signaling. Mechanistically, we delineate the "alternative Wnt-YAP/TAZ signaling axis" that consists of Wnt-FZD/ROR-Gα12/13-Rho GTPases-Lats1/2 to promote YAP/TAZ activation and TEAD-mediated transcription. YAP/TAZ mediate the biological functions of alternative Wnt signaling, including gene expression, osteogenic differentiation, cell migration, and antagonism of Wnt/ß-catenin signaling. Together, our work establishes YAP/TAZ as critical mediators of alternative Wnt signaling.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Fosfoproteínas/metabolismo , Vía de Señalización Wnt , Animales , Proteínas de Ciclo Celular , Línea Celular , Receptores Frizzled/metabolismo , Humanos , Ratones , Ratones Transgénicos , Transactivadores , Factores de Transcripción , Proteínas Señalizadoras YAP , beta Catenina/metabolismo
9.
Nature ; 625(7996): 768-777, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38200313

RESUMEN

Cerebrospinal fluid (CSF) in the subarachnoid space around the brain has long been known to drain through the lymphatics to cervical lymph nodes1-17, but the connections and regulation have been challenging to identify. Here, using fluorescent CSF tracers in Prox1-GFP lymphatic reporter mice18, we found that the nasopharyngeal lymphatic plexus is a major hub for CSF outflow to deep cervical lymph nodes. This plexus had unusual valves and short lymphangions but no smooth-muscle coverage, whereas downstream deep cervical lymphatics had typical semilunar valves, long lymphangions and smooth muscle coverage that transported CSF to the deep cervical lymph nodes. α-Adrenergic and nitric oxide signalling in the smooth muscle cells regulated CSF drainage through the transport properties of deep cervical lymphatics. During ageing, the nasopharyngeal lymphatic plexus atrophied, but deep cervical lymphatics were not similarly altered, and CSF outflow could still be increased by adrenergic or nitric oxide signalling. Single-cell analysis of gene expression in lymphatic endothelial cells of the nasopharyngeal plexus of aged mice revealed increased type I interferon signalling and other inflammatory cytokines. The importance of evidence for the nasopharyngeal lymphatic plexus functioning as a CSF outflow hub is highlighted by its regression during ageing. Yet, the ageing-resistant pharmacological activation of deep cervical lymphatic transport towards lymph nodes can still increase CSF outflow, offering an approach for augmenting CSF clearance in age-related neurological conditions in which greater efflux would be beneficial.


Asunto(s)
Líquido Cefalorraquídeo , Vértebras Cervicales , Drenaje , Vasos Linfáticos , Animales , Ratones , Envejecimiento/metabolismo , Líquido Cefalorraquídeo/metabolismo , Vértebras Cervicales/metabolismo , Células Endoteliales/metabolismo , Fluorescencia , Genes Reporteros , Interferón Tipo I/inmunología , Interferón Tipo I/metabolismo , Vasos Linfáticos/fisiología , Miocitos del Músculo Liso/metabolismo , Óxido Nítrico/metabolismo , Nariz/fisiología , Faringe/metabolismo , Receptores Adrenérgicos alfa/metabolismo , Análisis de la Célula Individual , Transducción de Señal
10.
Nature ; 626(7999): 603-610, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38297120

RESUMEN

Humans are capable of generating extraordinarily diverse articulatory movement combinations to produce meaningful speech. This ability to orchestrate specific phonetic sequences, and their syllabification and inflection over subsecond timescales allows us to produce thousands of word sounds and is a core component of language1,2. The fundamental cellular units and constructs by which we plan and produce words during speech, however, remain largely unknown. Here, using acute ultrahigh-density Neuropixels recordings capable of sampling across the cortical column in humans, we discover neurons in the language-dominant prefrontal cortex that encoded detailed information about the phonetic arrangement and composition of planned words during the production of natural speech. These neurons represented the specific order and structure of articulatory events before utterance and reflected the segmentation of phonetic sequences into distinct syllables. They also accurately predicted the phonetic, syllabic and morphological components of upcoming words and showed a temporally ordered dynamic. Collectively, we show how these mixtures of cells are broadly organized along the cortical column and how their activity patterns transition from articulation planning to production. We also demonstrate how these cells reliably track the detailed composition of consonant and vowel sounds during perception and how they distinguish processes specifically related to speaking from those related to listening. Together, these findings reveal a remarkably structured organization and encoding cascade of phonetic representations by prefrontal neurons in humans and demonstrate a cellular process that can support the production of speech.


Asunto(s)
Neuronas , Fonética , Corteza Prefrontal , Habla , Humanos , Movimiento , Neuronas/fisiología , Habla/fisiología , Percepción del Habla/fisiología , Corteza Prefrontal/citología , Corteza Prefrontal/fisiología
11.
Nature ; 627(8003): 347-357, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38374256

RESUMEN

Type 2 diabetes (T2D) is a heterogeneous disease that develops through diverse pathophysiological processes1,2 and molecular mechanisms that are often specific to cell type3,4. Here, to characterize the genetic contribution to these processes across ancestry groups, we aggregate genome-wide association study data from 2,535,601 individuals (39.7% not of European ancestry), including 428,452 cases of T2D. We identify 1,289 independent association signals at genome-wide significance (P < 5 × 10-8) that map to 611 loci, of which 145 loci are, to our knowledge, previously unreported. We define eight non-overlapping clusters of T2D signals that are characterized by distinct profiles of cardiometabolic trait associations. These clusters are differentially enriched for cell-type-specific regions of open chromatin, including pancreatic islets, adipocytes, endothelial cells and enteroendocrine cells. We build cluster-specific partitioned polygenic scores5 in a further 279,552 individuals of diverse ancestry, including 30,288 cases of T2D, and test their association with T2D-related vascular outcomes. Cluster-specific partitioned polygenic scores are associated with coronary artery disease, peripheral artery disease and end-stage diabetic nephropathy across ancestry groups, highlighting the importance of obesity-related processes in the development of vascular outcomes. Our findings show the value of integrating multi-ancestry genome-wide association study data with single-cell epigenomics to disentangle the aetiological heterogeneity that drives the development and progression of T2D. This might offer a route to optimize global access to genetically informed diabetes care.


Asunto(s)
Diabetes Mellitus Tipo 2 , Progresión de la Enfermedad , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Adipocitos/metabolismo , Cromatina/genética , Cromatina/metabolismo , Enfermedad de la Arteria Coronaria/complicaciones , Enfermedad de la Arteria Coronaria/genética , Diabetes Mellitus Tipo 2/clasificación , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patología , Diabetes Mellitus Tipo 2/fisiopatología , Nefropatías Diabéticas/complicaciones , Nefropatías Diabéticas/genética , Células Endoteliales/metabolismo , Células Enteroendocrinas , Epigenómica , Predisposición Genética a la Enfermedad/genética , Islotes Pancreáticos/metabolismo , Herencia Multifactorial/genética , Enfermedad Arterial Periférica/complicaciones , Enfermedad Arterial Periférica/genética , Análisis de la Célula Individual
12.
Nature ; 619(7968): 78-86, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37407684

RESUMEN

The paper-folding mechanism has been widely adopted in building of reconfigurable macroscale systems because of its unique capabilities and advantages in programming variable shapes and stiffness into a structure1-5. However, it has barely been exploited in the construction of molecular-level systems owing to the lack of a suitable design principle, even though various dynamic structures based on DNA self-assembly6-9 have been developed10-23. Here we propose a method to harness the paper-folding mechanism to create reconfigurable DNA origami structures. The main idea is to build a reference, planar wireframe structure24 whose edges follow a crease pattern in paper folding so that it can be folded into various target shapes. We realized several paper-like folding and unfolding patterns using DNA strand displacement25 with high yield. Orthogonal folding, repeatable folding and unfolding, folding-based microRNA detection and fluorescence signal control were demonstrated. Stimuli-responsive folding and unfolding triggered by pH or light-source change were also possible. Moreover, by employing hierarchical assembly26 we could expand the design space and complexity of the paper-folding mechanism in a highly programmable manner. Because of its high programmability and scalability, we expect that the proposed paper-folding-based reconfiguration method will advance the development of complex molecular systems.


Asunto(s)
ADN , Conformación de Ácido Nucleico , ADN/química , MicroARNs/análisis , MicroARNs/química , Fluorescencia , Concentración de Iones de Hidrógeno
13.
Nature ; 620(7972): 137-144, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37500978

RESUMEN

Many critics raise concerns about the prevalence of 'echo chambers' on social media and their potential role in increasing political polarization. However, the lack of available data and the challenges of conducting large-scale field experiments have made it difficult to assess the scope of the problem1,2. Here we present data from 2020 for the entire population of active adult Facebook users in the USA showing that content from 'like-minded' sources constitutes the majority of what people see on the platform, although political information and news represent only a small fraction of these exposures. To evaluate a potential response to concerns about the effects of echo chambers, we conducted a multi-wave field experiment on Facebook among 23,377 users for whom we reduced exposure to content from like-minded sources during the 2020 US presidential election by about one-third. We found that the intervention increased their exposure to content from cross-cutting sources and decreased exposure to uncivil language, but had no measurable effects on eight preregistered attitudinal measures such as affective polarization, ideological extremity, candidate evaluations and belief in false claims. These precisely estimated results suggest that although exposure to content from like-minded sources on social media is common, reducing its prevalence during the 2020 US presidential election did not correspondingly reduce polarization in beliefs or attitudes.


Asunto(s)
Actitud , Política , Medios de Comunicación Sociales , Adulto , Humanos , Emociones , Lenguaje , Estados Unidos , Desinformación
14.
Cell ; 152(1-2): 290-303, 2013 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-23332761

RESUMEN

Autophagy is a stress response protecting cells from unfavorable conditions, such as nutrient starvation. The class III phosphatidylinositol-3 kinase, Vps34, forms multiple complexes and regulates both intracellular vesicle trafficking and autophagy induction. Here, we show that AMPK plays a key role in regulating different Vps34 complexes. AMPK inhibits the nonautophagy Vps34 complex by phosphorylating T163/S165 in Vps34 and therefore suppresses overall PI(3)P production and protects cells from starvation. In parallel, AMPK activates the proautophagy Vps34 complex by phosphorylating S91/S94 in Beclin1 to induce autophagy. Atg14L, an autophagy-essential gene present only in the proautophagy Vps34 complex, inhibits Vps34 phosphorylation but increases Beclin1 phosphorylation by AMPK. As such, Atg14L dictates the differential regulation (either inhibition or activation) of different Vps34 complexes in response to glucose starvation. Our study reveals an intricate molecular regulation of Vps34 complexes by AMPK in nutrient stress response and autophagy.


Asunto(s)
Autofagia , Fosfatidilinositol 3-Quinasas Clase III/metabolismo , Proteínas Quinasas/metabolismo , Quinasas de la Proteína-Quinasa Activada por el AMP , Secuencia de Aminoácidos , Animales , Proteínas Reguladoras de la Apoptosis/química , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas Relacionadas con la Autofagia , Beclina-1 , Fosfatidilinositol 3-Quinasas Clase III/genética , Glucosa/metabolismo , Ratones , Datos de Secuencia Molecular , Complejos Multiproteicos/metabolismo , Fosforilación , Proteínas Quinasas/química , Proteínas Quinasas/genética , Alineación de Secuencia , Proteínas de Transporte Vesicular/metabolismo
15.
Nature ; 603(7901): 434-438, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35296844

RESUMEN

Oxidation can deteriorate the properties of copper that are critical for its use, particularly in the semiconductor industry and electro-optics applications1-7. This has prompted numerous studies exploring copper oxidation and possible passivation strategies8. In situ observations have, for example, shown that oxidation involves stepped surfaces: Cu2O growth occurs on flat surfaces as a result of Cu adatoms detaching from steps and diffusing across terraces9-11. But even though this mechanism explains why single-crystalline copper is more resistant to oxidation than polycrystalline copper, the fact that flat copper surfaces can be free of oxidation has not been explored further. Here we report the fabrication of copper thin films that are semi-permanently oxidation resistant because they consist of flat surfaces with only occasional mono-atomic steps. First-principles calculations confirm that mono-atomic step edges are as impervious to oxygen as flat surfaces and that surface adsorption of O atoms is suppressed once an oxygen face-centred cubic (fcc) surface site coverage of 50% has been reached. These combined effects explain the exceptional oxidation resistance of ultraflat Cu surfaces.

16.
Plant Cell ; 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38869214

RESUMEN

Anthocyanins play critical roles in protecting plant tissues against diverse stresses. The complicated regulatory networks induced by various environmental factors modulate the homeostatic level of anthocyanins. Here, we show that anthocyanin accumulation is induced by brassinosteroids (BRs) in Arabidopsis (Arabidopsis thaliana) shoots and shed light on the underlying regulatory mechanism. We observed that anthocyanin levels are altered considerably in BR-related mutants, and BRs induce anthocyanin accumulation by up-regulating the expression of anthocyanin biosynthetic genes. Our genetic analysis indicated that BRASSINAZOLE RESISTANT 1 (BZR1) and PRODUCTION OF ANTHOCYANIN PIGMENT 1 (PAP1) are essential for BR-induced anthocyanin accumulation. The BR-responsive transcription factor BZR1 directly binds to the PAP1 promoter, regulating its expression. In addition, we found that intense anthocyanin accumulation caused by the pap1-D dominant mutation is significantly reduced in BR mutants, implying that BR activity is required for PAP1 function after PAP1 transcription. Moreover, we demonstrated that BZR1 physically interacts with PAP1 to cooperatively regulate the expression of PAP1 target genes, such as TRANSPARENT TESTA 8 (TT8), DIHYDROFLAVONOL 4-REDUCTASE (DFR), and LEUKOANTHOCYANIDIN DIOXYGENASE (LDOX). Our findings indicate that BZR1 functions as an integral component of the PAP1-containing transcription factor complex, contributing to increased anthocyanin biosynthesis. Notably, we also show that functional interaction of BZR1 with PAP1 is required for anthocyanin accumulation induced by low nitrogen stress. Taken together, our results demonstrate that BR-regulated BZR1 promotes anthocyanin biosynthesis through cooperative interaction with PAP1 of the MBW complex.

17.
Nature ; 598(7881): 444-450, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34671136

RESUMEN

In perovskite solar cells, the interfaces between the perovskite and charge-transporting layers contain high concentrations of defects (about 100 times that within the perovskite layer), specifically, deep-level defects, which substantially reduce the power conversion efficiency of the devices1-3. Recent efforts to reduce these interfacial defects have focused mainly on surface passivation4-6. However, passivating the perovskite surface that interfaces with the electron-transporting layer is difficult, because the surface-treatment agents on the electron-transporting layer may dissolve while coating the perovskite thin film. Alternatively, interfacial defects may not be a concern if a coherent interface could be formed between the electron-transporting and perovskite layers. Here we report the formation of an interlayer between a SnO2 electron-transporting layer and a halide perovskite light-absorbing layer, achieved by coupling Cl-bonded SnO2 with a Cl-containing perovskite precursor. This interlayer has atomically coherent features, which enhance charge extraction and transport from the perovskite layer, and fewer interfacial defects. The existence of such a coherent interlayer allowed us to fabricate perovskite solar cells with a power conversion efficiency of 25.8 per cent (certified 25.5 per cent)under standard illumination. Furthermore, unencapsulated devices maintained about 90 per cent of their initial efficiency even after continuous light exposure for 500 hours. Our findings provide guidelines for designing defect-minimizing interfaces between metal halide perovskites and electron-transporting layers.

18.
Nature ; 590(7847): 587-593, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33627807

RESUMEN

Metal halide perovskite solar cells (PSCs) are an emerging photovoltaic technology with the potential to disrupt the mature silicon solar cell market. Great improvements in device performance over the past few years, thanks to the development of fabrication protocols1-3, chemical compositions4,5 and phase stabilization methods6-10, have made PSCs one of the most efficient and low-cost solution-processable photovoltaic technologies. However, the light-harvesting performance of these devices is still limited by excessive charge carrier recombination. Despite much effort, the performance of the best-performing PSCs is capped by relatively low fill factors and high open-circuit voltage deficits (the radiative open-circuit voltage limit minus the high open-circuit voltage)11. Improvements in charge carrier management, which is closely tied to the fill factor and the open-circuit voltage, thus provide a path towards increasing the device performance of PSCs, and reaching their theoretical efficiency limit12. Here we report a holistic approach to improving the performance of PSCs through enhanced charge carrier management. First, we develop an electron transport layer with an ideal film coverage, thickness and composition by tuning the chemical bath deposition of tin dioxide (SnO2). Second, we decouple the passivation strategy between the bulk and the interface, leading to improved properties, while minimizing the bandgap penalty. In forward bias, our devices exhibit an electroluminescence external quantum efficiency of up to 17.2 per cent and an electroluminescence energy conversion efficiency of up to 21.6 per cent. As solar cells, they achieve a certified power conversion efficiency of 25.2 per cent, corresponding to 80.5 per cent of the thermodynamic limit of its bandgap.

19.
Proc Natl Acad Sci U S A ; 121(10): e2310841121, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38412134

RESUMEN

Connectomics research has made it more feasible to explore how neural circuits can generate multiple outputs. Female sexual drive provides a good model for understanding reversible, long-term functional changes in motivational circuits. After emerging, female flies avoid male courtship, but they become sexually receptive over 2 d. Mating causes females to reject further mating for several days. Here, we report that pC1 neurons, which process male courtship and regulate copulation behavior, exhibit increased CREB (cAMP response element binding protein) activity during sexual maturation and decreased CREB activity after mating. This increased CREB activity requires the neuropeptide Dh44 (Diuretic hormone 44) and its receptors. A subset of the pC1 neurons secretes Dh44, which stimulates CREB activity and increases expression of the TRP channel Pyrexia (Pyx) in more pC1 neurons. This, in turn, increases pC1 excitability and sexual drive. Mating suppresses pyx expression and pC1 excitability. Dh44 is orthologous to the conserved corticotrophin-releasing hormone family, suggesting similar roles in other species.


Asunto(s)
Proteínas de Drosophila , Neuropéptidos , Animales , Masculino , Femenino , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Neuropéptidos/metabolismo , Copulación/fisiología , Cortejo , Hormonas , Conducta Sexual Animal/fisiología
20.
Proc Natl Acad Sci U S A ; 121(21): e2321584121, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38739793

RESUMEN

We study the effect of Facebook and Instagram access on political beliefs, attitudes, and behavior by randomizing a subset of 19,857 Facebook users and 15,585 Instagram users to deactivate their accounts for 6 wk before the 2020 U.S. election. We report four key findings. First, both Facebook and Instagram deactivation reduced an index of political participation (driven mainly by reduced participation online). Second, Facebook deactivation had no significant effect on an index of knowledge, but secondary analyses suggest that it reduced knowledge of general news while possibly also decreasing belief in misinformation circulating online. Third, Facebook deactivation may have reduced self-reported net votes for Trump, though this effect does not meet our preregistered significance threshold. Finally, the effects of both Facebook and Instagram deactivation on affective and issue polarization, perceived legitimacy of the election, candidate favorability, and voter turnout were all precisely estimated and close to zero.


Asunto(s)
Política , Medios de Comunicación Sociales , Humanos , Estados Unidos , Actitud , Masculino , Femenino
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