RESUMO
Melanoma brain metastasis (MBM) frequently occurs in patients with advanced melanoma; yet, our understanding of the underlying salient biology is rudimentary. Here, we performed single-cell/nucleus RNA-seq in 22 treatment-naive MBMs and 10 extracranial melanoma metastases (ECMs) and matched spatial single-cell transcriptomics and T cell receptor (TCR)-seq. Cancer cells from MBM were more chromosomally unstable, adopted a neuronal-like cell state, and enriched for spatially variably expressed metabolic pathways. Key observations were validated in independent patient cohorts, patient-derived MBM/ECM xenograft models, RNA/ATAC-seq, proteomics, and multiplexed imaging. Integrated spatial analyses revealed distinct geography of putative cancer immune evasion and evidence for more abundant intra-tumoral B to plasma cell differentiation in lymphoid aggregates in MBM. MBM harbored larger fractions of monocyte-derived macrophages and dysfunctional TOX+CD8+ T cells with distinct expression of immune checkpoints. This work provides comprehensive insights into MBM biology and serves as a foundational resource for further discovery and therapeutic exploration.
Assuntos
Neoplasias Encefálicas , Melanoma , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/secundário , Linfócitos T CD8-Positivos/patologia , Ecossistema , Humanos , RNA-SeqRESUMO
Contractile injection systems (CISs) are cell-puncturing nanodevices that share ancestry with contractile tail bacteriophages. Photorhabdus virulence cassette (PVC) represents one group of extracellular CISs that are present in both bacteria and archaea. Here, we report the cryo-EM structure of an intact PVC from P. asymbiotica. This over 10-MDa device resembles a simplified T4 phage tail, containing a hexagonal baseplate complex with six fibers and a capped 117-nanometer sheath-tube trunk. One distinct feature of the PVC is the presence of three variants for both tube and sheath proteins, indicating a functional specialization of them during evolution. The terminal hexameric cap docks onto the topmost layer of the inner tube and locks the outer sheath in pre-contraction state with six stretching arms. Our results on the PVC provide a framework for understanding the general mechanism of widespread CISs and pave the way for using them as delivery tools in biological or therapeutic applications.
Assuntos
Photorhabdus/química , Photorhabdus/ultraestrutura , Bacteriófago T4/química , Membrana Celular/química , Microscopia Crioeletrônica/métodos , Modelos Moleculares , Photorhabdus/metabolismo , Conformação Proteica , Sistemas de Secreção Tipo VI/metabolismoRESUMO
The convergence of topology and correlations represents a highly coveted realm in the pursuit of new quantum states of matter1. Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order2-8, not possible in quantum Hall and Chern insulator systems. Here we report a new dual QSH insulator within the intrinsic monolayer crystal of TaIrTe4, arising from the interplay of its single-particle topology and density-tuned electron correlations. At charge neutrality, monolayer TaIrTe4 demonstrates the QSH insulator, manifesting enhanced nonlocal transport and quantized helical edge conductance. After introducing electrons from charge neutrality, TaIrTe4 shows metallic behaviour in only a small range of charge densities but quickly goes into a new insulating state, entirely unexpected on the basis of the single-particle band structure of TaIrTe4. This insulating state could arise from a strong electronic instability near the van Hove singularities, probably leading to a charge density wave (CDW). Remarkably, within this correlated insulating gap, we observe a resurgence of the QSH state. The observation of helical edge conduction in a CDW gap could bridge spin physics and charge orders. The discovery of a dual QSH insulator introduces a new method for creating topological flat minibands through CDW superlattices, which offer a promising platform for exploring time-reversal-symmetric fractional phases and electromagnetism2-4,9,10.
RESUMO
Mitochondria are cellular powerhouses that generate energy through the electron transport chain (ETC). The mitochondrial genome (mtDNA) encodes essential ETC proteins in a compartmentalized manner, however, the mechanism underlying metabolic regulation of mtDNA function remains unknown. Here, we report that expression of tricarboxylic acid cycle enzyme succinate-CoA ligase SUCLG1 strongly correlates with ETC genes across various TCGA cancer transcriptomes. Mechanistically, SUCLG1 restricts succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase (POLRMT). Lysine 622 succinylation disrupts the interaction of POLRMT with mtDNA and mitochondrial transcription factors. SUCLG1-mediated POLRMT hyposuccinylation maintains mtDNA transcription, mitochondrial biogenesis, and leukemia cell proliferation. Specifically, leukemia-promoting FMS-like tyrosine kinase 3 (FLT3) mutations modulate nuclear transcription and upregulate SUCLG1 expression to reduce succinyl-CoA and POLRMT succinylation, resulting in enhanced mitobiogenesis. In line, genetic depletion of POLRMT or SUCLG1 significantly delays disease progression in mouse and humanized leukemia models. Importantly, succinyl-CoA level and POLRMT succinylation are downregulated in FLT3-mutated clinical leukemia samples, linking enhanced mitobiogenesis to cancer progression. Together, SUCLG1 connects succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development.
Assuntos
Biogênese de Organelas , Succinato-CoA Ligases , Animais , Humanos , Camundongos , Acil Coenzima A/metabolismo , Acil Coenzima A/genética , Linhagem Celular Tumoral , Proliferação de Células , Progressão da Doença , DNA Mitocondrial/metabolismo , DNA Mitocondrial/genética , RNA Polimerases Dirigidas por DNA/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Leucemia/metabolismo , Leucemia/genética , Leucemia/patologia , Mitocôndrias/metabolismo , Mitocôndrias/genética , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Succinato-CoA Ligases/metabolismo , Succinato-CoA Ligases/genéticaRESUMO
The observation of the Higgs boson solidified the standard model of particle physics. However, explanations of anomalies (for example, dark matter) rely on further symmetry breaking, calling for an undiscovered axial Higgs mode1. The Higgs mode was also seen in magnetic, superconducting and charge density wave (CDW) systems2,3. Uncovering the vector properties of a low-energy mode is challenging, and requires going beyond typical spectroscopic or scattering techniques. Here we discover an axial Higgs mode in the CDW system RTe3 using the interference of quantum pathways. In RTe3 (R = La, Gd), the electronic ordering couples bands of equal or different angular momenta4-6. As such, the Raman scattering tensor associated with the Higgs mode contains both symmetric and antisymmetric components, which are excited via two distinct but degenerate pathways. This leads to constructive or destructive interference of these pathways, depending on the choice of the incident and Raman-scattered light polarization. The qualitative behaviour of the Raman spectra is well captured by an appropriate tight-binding model, including an axial Higgs mode. Elucidation of the antisymmetric component is direct evidence that the Higgs mode contains an axial vector representation (that is, a pseudo-angular momentum) and hints that the CDW is unconventional. Thus, we provide a means for measuring quantum properties of collective modes without resorting to extreme experimental conditions.
RESUMO
The occurrence of plant disease is determined by interactions among host, pathogen, and environment. Air humidity shapes various aspects of plant physiology and high humidity has long been known to promote numerous phyllosphere diseases. However, the molecular basis of how high humidity interferes with plant immunity to favor disease has remained elusive. Here we show that high humidity is associated with an "immuno-compromised" status in Arabidopsis plants. Furthermore, accumulation and signaling of salicylic acid (SA), an important defense hormone, are significantly inhibited under high humidity. NPR1, an SA receptor and central transcriptional co-activator of SA-responsive genes, is less ubiquitinated and displays a lower promoter binding affinity under high humidity. The cellular ubiquitination machinery, particularly the Cullin 3-based E3 ubiquitin ligase mediating NPR1 protein ubiquitination, is downregulated under high humidity. Importantly, under low humidity the Cullin 3a/b mutant plants phenocopy the low SA gene expression and disease susceptibility that is normally observed under high humidity. Our study uncovers a mechanism by which high humidity dampens a major plant defense pathway and provides new insights into the long-observed air humidity influence on diseases.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ácido Salicílico/metabolismo , Umidade , Proteínas Culina/genética , Proteínas Culina/metabolismo , Arabidopsis/metabolismo , Plantas/metabolismo , Fatores de Transcrição/metabolismo , Doenças das Plantas/genética , Regulação da Expressão Gênica de PlantasRESUMO
The plant immune system is fundamental for plant survival in natural ecosystems and for productivity in crop fields. Substantial evidence supports the prevailing notion that plants possess a two-tiered innate immune system, called pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). PTI is triggered by microbial patterns via cell surface-localized pattern-recognition receptors (PRRs), whereas ETI is activated by pathogen effector proteins via predominantly intracellularly localized receptors called nucleotide-binding, leucine-rich repeat receptors (NLRs)1-4. PTI and ETI are initiated by distinct activation mechanisms and involve different early signalling cascades5,6. Here we show that Arabidopsis PRR and PRR co-receptor mutants-fls2 efr cerk1 and bak1 bkk1 cerk1 triple mutants-are markedly impaired in ETI responses when challenged with incompatible Pseudomonas syrinage bacteria. We further show that the production of reactive oxygen species by the NADPH oxidase RBOHD is a critical early signalling event connecting PRR- and NLR-mediated immunity, and that the receptor-like cytoplasmic kinase BIK1 is necessary for full activation of RBOHD, gene expression and bacterial resistance during ETI. Moreover, NLR signalling rapidly augments the transcript and/or protein levels of key PTI components. Our study supports a revised model in which potentiation of PTI is an indispensable component of ETI during bacterial infection. This revised model conceptually unites two major immune signalling cascades in plants and mechanistically explains some of the long-observed similarities in downstream defence outputs between PTI and ETI.
Assuntos
Arabidopsis/imunologia , Proteínas NLR/imunologia , Imunidade Vegetal/imunologia , Receptores de Reconhecimento de Padrão/imunologia , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/metabolismo , NADPH Oxidases/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas Serina-Treonina Quinases/metabolismo , Pseudomonas syringae/imunologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/imunologiaRESUMO
Respiratory failure is the leading cause of death in patients with severe SARS-CoV-2 infection1,2, but the host response at the lung tissue level is poorly understood. Here we performed single-nucleus RNA sequencing of about 116,000 nuclei from the lungs of nineteen individuals who died of COVID-19 and underwent rapid autopsy and seven control individuals. Integrated analyses identified substantial alterations in cellular composition, transcriptional cell states, and cell-to-cell interactions, thereby providing insight into the biology of lethal COVID-19. The lungs from individuals with COVID-19 were highly inflamed, with dense infiltration of aberrantly activated monocyte-derived macrophages and alveolar macrophages, but had impaired T cell responses. Monocyte/macrophage-derived interleukin-1ß and epithelial cell-derived interleukin-6 were unique features of SARS-CoV-2 infection compared to other viral and bacterial causes of pneumonia. Alveolar type 2 cells adopted an inflammation-associated transient progenitor cell state and failed to undergo full transition into alveolar type 1 cells, resulting in impaired lung regeneration. Furthermore, we identified expansion of recently described CTHRC1+ pathological fibroblasts3 contributing to rapidly ensuing pulmonary fibrosis in COVID-19. Inference of protein activity and ligand-receptor interactions identified putative drug targets to disrupt deleterious circuits. This atlas enables the dissection of lethal COVID-19, may inform our understanding of long-term complications of COVID-19 survivors, and provides an important resource for therapeutic development.
Assuntos
COVID-19/patologia , COVID-19/virologia , Pulmão/patologia , SARS-CoV-2/patogenicidade , Análise de Célula Única , Idoso , Idoso de 80 Anos ou mais , Células Epiteliais Alveolares/patologia , Células Epiteliais Alveolares/virologia , Atlas como Assunto , Autopsia , COVID-19/imunologia , Estudos de Casos e Controles , Feminino , Fibroblastos/patologia , Fibrose/patologia , Fibrose/virologia , Humanos , Inflamação/patologia , Inflamação/virologia , Macrófagos/patologia , Macrófagos/virologia , Macrófagos Alveolares/patologia , Macrófagos Alveolares/virologia , Masculino , Pessoa de Meia-Idade , Plasmócitos/imunologia , Linfócitos T/imunologiaRESUMO
COVID-19, which is caused by SARS-CoV-2, can result in acute respiratory distress syndrome and multiple organ failure1-4, but little is known about its pathophysiology. Here we generated single-cell atlases of 24 lung, 16 kidney, 16 liver and 19 heart autopsy tissue samples and spatial atlases of 14 lung samples from donors who died of COVID-19. Integrated computational analysis uncovered substantial remodelling in the lung epithelial, immune and stromal compartments, with evidence of multiple paths of failed tissue regeneration, including defective alveolar type 2 differentiation and expansion of fibroblasts and putative TP63+ intrapulmonary basal-like progenitor cells. Viral RNAs were enriched in mononuclear phagocytic and endothelial lung cells, which induced specific host programs. Spatial analysis in lung distinguished inflammatory host responses in lung regions with and without viral RNA. Analysis of the other tissue atlases showed transcriptional alterations in multiple cell types in heart tissue from donors with COVID-19, and mapped cell types and genes implicated with disease severity based on COVID-19 genome-wide association studies. Our foundational dataset elucidates the biological effect of severe SARS-CoV-2 infection across the body, a key step towards new treatments.
Assuntos
COVID-19/patologia , COVID-19/virologia , Rim/patologia , Fígado/patologia , Pulmão/patologia , Miocárdio/patologia , SARS-CoV-2/patogenicidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Atlas como Assunto , Autopsia , Bancos de Espécimes Biológicos , COVID-19/genética , COVID-19/imunologia , Células Endoteliais , Células Epiteliais/patologia , Células Epiteliais/virologia , Feminino , Fibroblastos , Estudo de Associação Genômica Ampla , Coração/virologia , Humanos , Inflamação/patologia , Inflamação/virologia , Rim/virologia , Fígado/virologia , Pulmão/virologia , Masculino , Pessoa de Meia-Idade , Especificidade de Órgãos , Fagócitos , Alvéolos Pulmonares/patologia , Alvéolos Pulmonares/virologia , RNA Viral/análise , Regeneração , SARS-CoV-2/imunologia , Análise de Célula Única , Carga ViralRESUMO
Introducing nitrogen fixation (nif â) genes into eukaryotic genomes and targeting Nif components to mitochondria or chloroplasts is a promising strategy for engineering nitrogen-fixing plants. A prerequisite for achieving nitrogen fixation in crops is stable and stoichiometric expression of each component in organelles. Previously, we designed a polyprotein-based nitrogenase system depending on Tobacco Etch Virus protease (TEVp) to release functional Nif components from five polyproteins. Although this system satisfies the demand for specific expression ratios of Nif components in Escherichia coli, we encountered issues with TEVp cleavage of polyproteins targeted to yeast mitochondria. To overcome this obstacle, a version of the Nif polyprotein system was constructed by replacing TEVp cleavage sites with minimal peptide sequences, identified by knowledge-based engineering, that are susceptible to cleavage by the endogenous mitochondrial-processing peptidase. This replacement not only further reduces the number of genes required, but also prevents potential precleavage of polyproteins outside the target organelle. This version of the polyprotein-based nitrogenase system achieved levels of nitrogenase activity in E. coli, comparable to those observed with the TEVp-based polyprotein nitrogenase system. When applied to yeast mitochondria, stable and balanced expression of Nif components was realized. This strategy has potential advantages, not only for transferring nitrogen fixation to eukaryotic cells, but also for the engineering of other metabolic pathways that require mitochondrial compartmentalization.
Assuntos
Escherichia coli , Fixação de Nitrogênio , Fixação de Nitrogênio/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Saccharomyces cerevisiae/metabolismo , Poliproteínas/genética , Poliproteínas/metabolismo , Nitrogenase/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Nitrogênio/metabolismoRESUMO
The role of Culex mosquitoes in the transmission of Japanese encephalitis virus (JEV) is crucial, yet the mechanisms of JEV infection in these vectors remain unclear. Previous research has indicated that various host factors participate in JEV infection. Herein, we present evidence that mosquito sialic acids enhance JEV infection both in vivo and in vitro. By treating mosquitoes and C6/36 cells with neuraminidase or lectin, the function of sialic acids is effectively blocked, resulting in significant inhibition of JEV infection. Furthermore, knockdown of the sialic acid biosynthesis genes in Culex mosquitoes also leads to a reduction in JEV infection. Moreover, our research revealed that sialic acids play a role in the attachment of JEV to mosquito cells, but not in its internalization. To further explore the mechanisms underlying the promotion of JEV attachment by sialic acids, we conducted immunoprecipitation experiments to confirm the direct binding of sialic acids to the last α-helix in JEV envelope protein domain III. Overall, our study contributes to a molecular comprehension of the interaction between mosquitoes and JEV and offers potential strategies for preventing the dissemination of flavivirus in natural environments.IMPORTANCEIn this study, we aimed to investigate the impact of glycoconjugate sialic acids on mosquito infection with Japanese encephalitis virus (JEV). Our findings demonstrate that sialic acids play a crucial role in enhancing JEV infection by facilitating the attachment of the virus to the cell membrane. Furthermore, our investigation revealed that sialic acids directly bind to the final α-helix in the JEV envelope protein domain III, thereby accelerating virus adsorption. Collectively, our results highlight the significance of mosquito sialic acids in JEV infection within vectors, contributing to a better understanding of the interaction between mosquitoes and JEV.
Assuntos
Culex , Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa , Ácidos Siálicos , Ligação Viral , Animais , Camundongos , Linhagem Celular , Culex/virologia , Culex/metabolismo , Vírus da Encefalite Japonesa (Espécie)/fisiologia , Vírus da Encefalite Japonesa (Espécie)/metabolismo , Encefalite Japonesa/virologia , Encefalite Japonesa/metabolismo , Mosquitos Vetores/virologia , Neuraminidase/metabolismo , Neuraminidase/genética , Ácidos Siálicos/metabolismo , Proteínas do Envelope Viral/metabolismo , Proteínas do Envelope Viral/genética , Internalização do VírusRESUMO
The mucilage surrounding hydrated Arabidopsis thaliana seeds is a specialized extracellular matrix composed mainly of the pectic polysaccharide rhamnogalacturonan I (RG-I). Although, several genes responsible for RG-I biosynthesis have been identified, the transcriptional regulatory mechanisms controlling RG-I production remain largely unknown. Here we report that the trihelix transcription factor DE1 BINDING FACTOR 1 (DF1) is a key regulator of mucilage RG-I biosynthesis. RG-I biosynthesis is significantly reduced in loss-of-function mutants of DF1. DF1 physically interacts with GLABRA2 (GL2) and both proteins transcriptionally regulate the expression of the RG-I biosynthesis genes MUCILAGE MODIFIED 4 (MUM4) and GALACTURONOSYLTRANSFERASE-LIKE5 (GATL5). Through chromatin immunoprecipitation-quantitative PCR and transcriptional activation assays, we uncover a cooperative mechanism of the DF1-GL2 module in activating MUM4 and GATL5 expression, in which DF1 binds to the promoters of MUM4 and GATL5 through interacting with GL2 and facilitates the transcriptional activity of GL2. The expression of DF1 and GL2 is directly regulated by TRANSPARENT TESTA GLABRA2 (TTG2) and, in turn, DF1 directly represses the expression of TTG2. Taken together, our data reveal that the transcriptional regulation of mucilage RG-I biosynthesis involves a regulatory module, comprising DF1, GL2, and TTG2.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Mucilagem Vegetal , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Pectinas , Mucilagem Vegetal/metabolismo , Polissacarídeos/metabolismo , Sementes/genética , Sementes/metabolismoRESUMO
The germinal center (GC) plays a central role in the generation of antigen-specific B cells and antibodies. Tight regulation of the GC is essential due to the inherent risks of tumorigenesis and autoimmunity posed by inappropriate GC B cell processes. Gammaherpesviruses such as Epstein-Barr virus (EBV) and murine gammaherpesvirus 68 (MHV68) utilize numerous armaments to drive infected naïve B cells, independent of antigen, through GC reactions to expand the latently infected B cell population and establish a stable latency reservoir. We previously demonstrated that the MHV68 microRNA (miRNA) mghv-miR-M1-7-5p represses host EWSR1 (Ewing sarcoma breakpoint region 1) to promote B cell infection. EWSR1 is a transcription and splicing regulator that is recognized for its involvement as a fusion protein in Ewing sarcoma. A function for EWSR1 in B cell responses has not been previously reported. Here, we demonstrate that 1) B cell-specific deletion of EWSR1 had no effect on generation of mature B cell subsets or basal immunoglobulin levels in naïve mice, 2) repression or ablation of EWSR1 in B cells promoted expansion of MHV68 latently infected GC B cells, and 3) B cell-specific deletion of EWSR1 during a normal immune response to nonviral antigen resulted in significantly elevated numbers of antigen-specific GC B cells, plasma cells, and circulating antibodies. Notably, EWSR1 deficiency did not affect the proliferation or survival of GC B cells but instead resulted in the generation of increased numbers of precursor GC B cells. Cumulatively, these findings demonstrate that EWSR1 is a negative regulator of B cell responses.
Assuntos
Linfócitos B , Gammaherpesvirinae , Centro Germinativo , Infecções por Herpesviridae , MicroRNAs , Proteína EWS de Ligação a RNA , Infecções Tumorais por Vírus , Animais , Linfócitos B/imunologia , Linfócitos B/virologia , Gammaherpesvirinae/genética , Gammaherpesvirinae/fisiologia , Deleção de Genes , Centro Germinativo/imunologia , Centro Germinativo/virologia , Infecções por Herpesviridae/genética , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/virologia , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , Proteína EWS de Ligação a RNA/genética , Proteína EWS de Ligação a RNA/metabolismo , Infecções Tumorais por Vírus/genética , Infecções Tumorais por Vírus/imunologia , Infecções Tumorais por Vírus/virologia , Latência ViralRESUMO
The emergence of antibiotic and antifungal resistant microorganisms represents nowadays a major public health issue that might push humanity into a post-antibiotic/antifungal era. One of the approaches to avoid such a catastrophe is to advance rapid antibiotic and antifungal susceptibility tests. In this study, we present a compact, optical fiber-based nanomotion sensor to achieve this goal by monitoring the dynamic nanoscale oscillation of a cantilever related to microorganism viability. High detection sensitivity was achieved that was attributed to the flexible two-photon polymerized cantilever with a spring constant of 0.3 N/m. This nanomotion device showed an excellent performance in the susceptibility tests of Escherichia coli and Candida albicans with a fast response in a time frame of minutes. As a proof-of-concept, with the simplicity of use and the potential of parallelization, our innovative sensor is anticipated to be an interesting candidate for future rapid antibiotic and antifungal susceptibility tests and other biomedical applications.
Assuntos
Antibacterianos , Antifúngicos , Fibras Ópticas , Testes de Sensibilidade Microbiana , Candida albicans , Escherichia coliRESUMO
Fiber-integrated micro/nanostructures play a crucial role in modern industry, mainly owing to their compact size, high sensitivity, and resistance to electromagnetic interference. However, the three-dimensional manufacturing of fiber-tip functional structures beyond organic polymers remains challenging. It is essential to construct fiber-integrated inorganic silica with designed functional nanostructures for microsystem applications. Here, we develop a strategy for the 3D nanolithography of fiber-integrated silica from hybrid organic-inorganic materials by ultrafast laser-induced multiphoton absorption. Without silica nanoparticles and polymer additives, the acrylate-functionalized precursors can be locally cross-linked through a nonlinear effect. Followed by annealing at low temperature, the as-printed micro/nanostructures are transformed to high-quality silica with sub-100 nm resolution. Silica microcantilever probes and microtoroid resonators are directly integrated onto the optical fiber, showing strong thermal stability and quality factors. This work provides a promising strategy for fabricating desired fiber-tip silica micro/nanostructures, which is helpful for the development of integrated functional device applications.
RESUMO
IMPORTANCE: The human gammaherpesviruses Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus are etiologic agents of numerous B cell lymphomas. A hallmark of gammaherpesvirus infection is their ability to establish lifelong latency in B cells. However, the specific mechanisms that mediate chronic infection in B cells in vivo remain elusive. Cellular E3 ubiquitin ligases regulate numerous biological processes by catalyzing ubiquitylation and modifying protein location, function, or half-life. Many viruses hijack host ubiquitin ligases to evade antiviral host defense and promote viral fitness. Here, we used the murine gammaherpesvirus 68 in vivo system to demonstrate that the E3 ligase Cul4b is essential for this virus to establish latency in germinal center B cells. These findings highlight an essential role for this E3 ligase in promoting chronic gammaherpesvirus infection in vivo and suggest that targeted inhibition of E3 ligases may provide a novel and effective intervention strategy against gammaherpesvirus-associated diseases.
Assuntos
Linfócitos B , Gammaherpesvirinae , Infecções por Herpesviridae , Infecção Persistente , Animais , Camundongos , Linfócitos B/enzimologia , Linfócitos B/metabolismo , Linfócitos B/virologia , Proteínas Culina/metabolismo , Gammaherpesvirinae/fisiologia , Centro Germinativo/citologia , Centro Germinativo/virologia , Infecções por Herpesviridae/enzimologia , Infecções por Herpesviridae/virologia , Infecção Persistente/enzimologia , Infecção Persistente/virologia , Ubiquitinas/metabolismo , Latência ViralRESUMO
The apoplast of plant leaves, the intercellular space between mesophyll cells, is normally largely filled with air with a minimal amount of liquid water in it, which is essential for key physiological processes such as gas exchange to occur. Phytopathogens exploit virulence factors to induce a water-rich environment, or "water-soaked" area, in the apoplast of the infected leaf tissue to promote disease. We propose that plants evolved a "water soaking" pathway, which normally keeps a nonflooded leaf apoplast for plant growth but is disturbed by microbial pathogens to facilitate infection. Investigation of the "water soaking" pathway and leaf water control mechanisms is a fundamental, yet previously overlooked, aspect of plant physiology. To identify key components in the "water soaking" pathway, we performed a genetic screen to isolate Arabidopsis (Arabidopsis thaliana) severe water soaking (sws) mutants that show liquid water overaccumulation in the leaf under high air humidity, a condition required for visible water soaking. Here, we report the sws1 mutant, which displays rapid water soaking upon high humidity treatment due to a loss-of-function mutation in CURLY LEAF (CLF), encoding a histone methyltransferase in the POLYCOMB REPRESSIVE COMPLEX 2 (PRC2). We found that the sws1 (clf) mutant exhibits enhanced abscisic acid (ABA) levels and stomatal closure, which are indispensable for its water soaking phenotype and mediated by CLF's epigenetic regulation of a group of ABA-associated NAM, ATAF, and CUC (NAC) transcription factor genes, NAC019/055/072. The clf mutant showed weakened immunity, which likely also contributes to the water soaking phenotype. In addition, the clf plant supports a substantially higher level of Pseudomonas syringae pathogen-induced water soaking and bacterial multiplication, in an ABA pathway and NAC019/055/072-dependent manner. Collectively, our study sheds light on an important question in plant biology and demonstrates CLF as a key modulator of leaf liquid water status via epigenetic regulation of the ABA pathway and stomatal movement.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Água/metabolismo , Epigênese Genética , Ácido Abscísico/farmacologia , Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Estômatos de Plantas/metabolismo , Proteínas de Homeodomínio/genéticaRESUMO
The three-dimensional (3D) light field display (LFD) with dense views can provide smooth motion parallax for the human eye. Increasing the number of views will widen the lens pitch, however, resulting in a decrease in view resolution. In this paper, an approach to smooth motion parallax based on optimizing the divergence angle of the light beam (DALB) for 3D LFD with narrow pitch is proposed. DALB is controlled by lens design. A views-fitting optimization algorithm is established based on a mathematical model between DALB and view distribution. Subsequently, the lens is reversely designed based on the optimization results. A co-designed convolutional neural network (CNN) is used to implement the algorithm. The optical experiment shows that a smooth motion parallax 3D image is achievable through the proposed method.
RESUMO
The investigation into the spectral properties and refractive index (RI) sensitivities at low RI region of helical intermedium-period fiber gratings (HIPFGs) with varied periods ranging from 10-48â µm is presented in detail for the first time. The structure of HIPFG is optimized for RI sensing in the RI range of 1.3-1.33 by comparing the optical properties of HIPFGs with different grating periods. The HIPFG with optimized structure is demonstrated to have a high average sensitivity of 302.5â nm/RIU in the RI ranging from 1.3 to 1.33, which is two orders more elevated than the traditional long-period fiber gratings. The improved HIPFG is also experimentally applied to breath monitoring in different states. Normal breath, slow breath, fast breath, and unhealthy breath are distinguished based on breathing rate, intensity, and time of exhalation and inhalation. The fastest response time is determined to be 10â ms. The results demonstrate that the optical fiber's sensitivity in the low RI region can be increased by shortening its period, offering a special strategy for improving detection performance of HIPFGs. By verifying its performance in breathing monitoring, it is proved that the optimized HIPFG sensor has the great potential to expand medical applications.
RESUMO
Totally video-guided thorascopic cardiac surgery (TVTCS) represents one of the most minimally invasive access routes to the heart. Its feasibility and safety can be guaranteed by an experienced surgeon with skilled operative techniques under the guidance of a video signal via thoracoscopy and the imaging from transesophageal echocardiography. At present, this surgical approach has been applied for atrioventricular valve disease, atrial septum defects plus and partial anomalous pulmonary venous drainage, cardiac tumors, hypertrophic obstructive cardiomyopathy, aortic valve disease, and atrial fibrillation. Multimodality cardiovascular imaging, including echocardiography, X-ray, computed tomography (CT), magnetic resonance imaging (MRI) and cardiac catheterization, provides morphologic characteristics and function status of the cardiovascular system and a comprehensive view of the target anatomy. In this review, the benefits of multimodality cardiovascular imaging are summarized for the clinical practice of TVTCS, including the preoperative preparation, intraoperative guidance and postoperative supervision. The disease categories are also individually reviewed on the basis of multimodality cardiovascular imaging, to ensure the feasibility and safety for TVTCS. Cardiovascular imaging technologies not only confirm who is a candidate for this surgical technique, but also provide technical support during the procedure and for postop follow to assess the clinical outcomes. Multimodality cardiovascular imaging is instrumental to provide the requirements to solve the problems for conduction of TVTCS; and to provide individualized protocols with high-resolution and real-time dynamic imaging fusion.