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Gasdermin D (GSDMD)-activated inflammatory cell death (pyroptosis) causes mitochondrial damage, but its underlying mechanism and functional consequences are largely unknown. Here, we show that the N-terminal pore-forming GSDMD fragment (GSDMD-NT) rapidly damaged both inner and outer mitochondrial membranes (OMMs) leading to reduced mitochondrial numbers, mitophagy, ROS, loss of transmembrane potential, attenuated oxidative phosphorylation (OXPHOS), and release of mitochondrial proteins and DNA from the matrix and intermembrane space. Mitochondrial damage occurred as soon as GSDMD was cleaved prior to plasma membrane damage. Mitochondrial damage was independent of the B-cell lymphoma 2 family and depended on GSDMD-NT binding to cardiolipin. Canonical and noncanonical inflammasome activation of mitochondrial damage, pyroptosis, and inflammatory cytokine release were suppressed by genetic ablation of cardiolipin synthase (Crls1) or the scramblase (Plscr3) that transfers cardiolipin to the OMM. Phospholipid scramblase-3 (PLSCR3) deficiency in a tumor compromised pyroptosis-triggered anti-tumor immunity. Thus, mitochondrial damage plays a critical role in pyroptosis.
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Gasderminas , Piroptose , Proteínas de Neoplasias/metabolismo , Cardiolipinas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Inflamassomos/metabolismoRESUMO
The GATOR2-GATOR1 signaling axis is essential for amino-acid-dependent mTORC1 activation. However, the molecular function of the GATOR2 complex remains unknown. Here, we report that disruption of the Ring domains of Mios, WDR24, or WDR59 completely impedes amino-acid-mediated mTORC1 activation. Mechanistically, via interacting with Ring domains of WDR59 and WDR24, the Ring domain of Mios acts as a hub to maintain GATOR2 integrity, disruption of which leads to self-ubiquitination of WDR24. Physiologically, leucine stimulation dissociates Sestrin2 from the Ring domain of WDR24 and confers its availability to UBE2D3 and subsequent ubiquitination of NPRL2, contributing to GATOR2-mediated GATOR1 inactivation. As such, WDR24 ablation or Ring deletion prevents mTORC1 activation, leading to severe growth defects and embryonic lethality at E10.5 in mice. Hence, our findings demonstrate that Ring domains are essential for GATOR2 to transmit amino acid availability to mTORC1 and further reveal the essentiality of nutrient sensing during embryonic development.
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Complexos Multiproteicos , Serina-Treonina Quinases TOR , Animais , Camundongos , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/metabolismo , Transdução de SinaisRESUMO
Aberrant energy status contributes to multiple metabolic diseases, including obesity, diabetes, and cancer, but the underlying mechanism remains elusive. Here, we report that ketogenic-diet-induced changes in energy status enhance the efficacy of anti-CTLA-4 immunotherapy by decreasing PD-L1 protein levels and increasing expression of type-I interferon (IFN) and antigen presentation genes. Mechanistically, energy deprivation activates AMP-activated protein kinase (AMPK), which in turn, phosphorylates PD-L1 on Ser283, thereby disrupting its interaction with CMTM4 and subsequently triggering PD-L1 degradation. In addition, AMPK phosphorylates EZH2, which disrupts PRC2 function, leading to enhanced IFNs and antigen presentation gene expression. Through these mechanisms, AMPK agonists or ketogenic diets enhance the efficacy of anti-CTLA-4 immunotherapy and improve the overall survival rate in syngeneic mouse tumor models. Our findings reveal a pivotal role for AMPK in regulating the immune response to immune-checkpoint blockade and advocate for combining ketogenic diets or AMPK agonists with anti-CTLA4 immunotherapy to combat cancer.
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Proteínas Quinases Ativadas por AMP/genética , Antígeno B7-H1/genética , Neoplasias da Mama/genética , Antígeno CTLA-4/genética , Neoplasias Colorretais/genética , Inibidores de Checkpoint Imunológico , Proteínas Quinases Ativadas por AMP/imunologia , Aloenxertos , Animais , Anticorpos Neutralizantes/farmacologia , Antineoplásicos/farmacologia , Antígeno B7-H1/imunologia , Compostos de Bifenilo/farmacologia , Neoplasias da Mama/imunologia , Neoplasias da Mama/mortalidade , Neoplasias da Mama/terapia , Antígeno CTLA-4/antagonistas & inibidores , Antígeno CTLA-4/imunologia , Linhagem Celular Tumoral , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/terapia , Dieta Cetogênica/métodos , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/imunologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Imunoterapia/métodos , Proteínas com Domínio MARVEL/genética , Proteínas com Domínio MARVEL/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Pironas/farmacologia , Transdução de Sinais , Análise de Sobrevida , Tiofenos/farmacologiaRESUMO
Adenosine-to-inosine (A-to-I) editing is the most prevalent type of RNA editing in animals, and it occurs in fungi specifically during sexual reproduction. However, it is debatable whether A-to-I RNA editing is adaptive. Deciphering the functional importance of individual editing sites is essential for the mechanistic understanding of the adaptive advantages of RNA editing. Here, by performing gene deletion for 17 genes with conserved missense editing (CME) sites and engineering underedited (ue) and overedited (oe) mutants for 10 CME sites using site-specific mutagenesis at the native locus in Fusarium graminearum, we demonstrated that two CME sites in CME5 and CME11 genes are functionally important for sexual reproduction. Although the overedited mutant was normal in sexual reproduction, the underedited mutant of CME5 had severe defects in ascus and ascospore formation like the deletion mutant, suggesting that the CME site of CME5 is co-opted for sexual development. The preediting residue of Cme5 is evolutionarily conserved across diverse classes of Ascomycota, while the postediting one is rarely hardwired into the genome, implying that editing at this site leads to higher fitness than a genomic A-to-G mutation. More importantly, mutants expressing only the underedited or the overedited allele of CME11 are defective in ascosporogenesis, while those expressing both alleles displayed normal phenotypes, indicating that concurrently expressing edited and unedited versions of Cme11 is more advantageous than either. Our study provides convincing experimental evidence for the long-suspected adaptive advantages of RNA editing in fungi and likely in animals.
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Ascomicetos , RNA , Animais , Edição de RNA/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Mutação , Ascomicetos/genéticaRESUMO
Toll-like receptor 4 (TLR4) sensing of lipopolysaccharide (LPS), the most potent pathogen-associated molecular pattern of gram-negative bacteria, activates NF-κB and Irf3, which induces inflammatory cytokines and interferons that trigger an intense inflammatory response, which is critical for host defense but can also cause serious inflammatory pathology, including sepsis. Although TLR4 inhibition is an attractive therapeutic approach for suppressing overexuberant inflammatory signaling, previously identified TLR4 antagonists have not shown any clinical benefit. Here, we identify disulfiram (DSF), an FDA-approved drug for alcoholism, as a specific inhibitor of TLR4-mediated inflammatory signaling. TLR4 cell surface expression, LPS sensing, dimerization and signaling depend on TLR4 binding to MD-2. DSF and other cysteine-reactive drugs, previously shown to block LPS-triggered inflammatory cell death (pyroptosis), inhibit TLR4 signaling by covalently modifying Cys133 of MD-2, a key conserved residue that mediates TLR4 sensing and signaling. DSF blocks LPS-triggered inflammatory cytokine, chemokine, and interferon production by macrophages in vitro. In the aggressive N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease (PD) in which TLR4 plays an important role, DSF markedly suppresses neuroinflammation and dopaminergic neuron loss, and restores motor function. Our findings identify a role for DSF in curbing TLR4-mediated inflammation and suggest that DSF and other drugs that target MD-2 might be useful for treating PD and other diseases in which inflammation contributes importantly to pathogenesis.
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Alcoolismo , Dissulfiram , Animais , Camundongos , Receptor 4 Toll-Like , Lipopolissacarídeos , Transdução de Sinais , CitocinasRESUMO
Meiosis is essential for generating genetic diversity and sexual spores, but the regulation of meiosis and ascosporogenesis is not clear in filamentous fungi, in which dikaryotic and diploid cells formed inside fruiting bodies are not free living and independent of pheromones or pheromone receptors. In this study, Gia1, a non-pheromone GPCR (G protein-coupled receptor) with sexual-specific expression in Fusarium graminearum, is found to be essential for ascosporogenesis. The gia1 mutant was normal in perithecium development, crozier formation, and karyogamy but failed to undergo meiosis, which could be partially rescued by a dominant active mutation in GPA1 and activation of the Gpmk1 pathway. GIA1 orthologs have conserved functions in regulating meiosis and ascosporogenesis in Sordariomycetes. GIA1 has a paralog, GIP1, in F. graminearum and other Hypocreales species which is essential for perithecium formation. GIP1 differed from GIA1 in expression profiles and downstream signaling during sexual reproduction. Whereas the C-terminal tail and IR3 were important for intracellular signaling, the N-terminal region and EL3 of Gia1 were responsible for recognizing its ligand, which is likely a protein enriched in developing perithecia, particularly in the gia1 mutant. Taken together, these results showed that GIA1 encodes a non-pheromone GPCR that regulates the entry into meiosis and ascosporogenesis via the downstream Gpmk1 MAP kinase pathway in F. graminearum and other filamentous ascomycetes.
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Ascomicetos , Fusarium , Triticum/microbiologia , Feromônios/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fusarium/genética , Ascomicetos/genética , Ascomicetos/metabolismo , Meiose/genética , Esporos FúngicosRESUMO
The mechanistic target of rapamycin complex 1 (mTORC1) is indispensable for preserving cellular and organismal homeostasis by balancing the anabolic and catabolic processes in response to various environmental cues, such as nutrients, growth factors, energy status, oxygen levels, and stress. Dysregulation of mTORC1 signaling is associated with the progression of many types of human disorders including cancer, age-related diseases, neurodegenerative disorders, and metabolic diseases. The way mTORC1 senses various upstream signals and converts them into specific downstream responses remains a crucial question with significant impacts for our perception of the related physiological and pathological process. In this review, we discuss the recent molecular and functional insights into the nutrient sensing of the mTORC1 signaling pathway, along with the emerging role of deregulating nutrient-mTORC1 signaling in cancer and age-related disorders.
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Apple Valsa canker (AVC) is a devastating disease of apple (Malus × domestica), caused by Valsa mali (Vm). The Cysteine-rich secretory protein, Antigen 5, and Pathogenesis-related protein 1 (CAP) superfamily protein PATHOGENESIS-RELATED PROTEIN 1-LIKE PROTEIN c (VmPR1c) plays an important role in the pathogenicity of Vm. However, the mechanisms through which it exerts its virulence function in Vm-apple interactions remain unclear. In this study, we identified an apple valine-glutamine (VQ)-motif-containing protein, MdVQ29, as a VmPR1c target protein. MdVQ29-overexpressing transgenic apple plants showed substantially enhanced AVC resistance as compared with the wild type. MdVQ29 interacted with the transcription factor MdWRKY23, which was further shown to bind to the promoter of the jasmonic acid (JA) signaling-related gene CORONATINE INSENSITIVE 1 (MdCOI1) and activate its expression to activate the JA signaling pathway. Disease evaluation in lesion areas on infected leaves showed that MdVQ29 positively modulated apple resistance in a MdWRKY23-dependent manner. Furthermore, MdVQ29 promoted the transcriptional activity of MdWRKY23 toward MdCOI1. In addition, VmPR1c suppressed the MdVQ29-enhanced transcriptional activation activity of MdWRKY23 by promoting the degradation of MdVQ29 and inhibiting MdVQ29 expression and the MdVQ29-MdWRKY23 interaction, thereby interfering with the JA signaling pathway and facilitating Vm infection. Overall, our results demonstrate that VmPR1c targets MdVQ29 to manipulate the JA signaling pathway to regulate immunity. Thus, this study provides an important theoretical basis and guidance for mining and utilizing disease-resistance genetic resources for genetically improving apples.
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Ascomicetos , Ciclopentanos , Malus , Oxilipinas , Malus/genética , Malus/metabolismo , Glutamina/metabolismo , Valina/metabolismo , Transdução de Sinais , Doenças das Plantas/genéticaRESUMO
Metagenomic data plays a crucial role in analyzing the relationship between microbes and diseases. However, the limited number of samples, high dimensionality, and sparsity of metagenomic data pose significant challenges for the application of deep learning in data classification and prediction. Previous studies have shown that utilizing the phylogenetic tree structure to transform metagenomic abundance data into a 2D matrix input for convolutional neural networks (CNNs) improves classification performance. Inspired by the success of a Permutable MLP-like architecture in visual recognition, we propose Metagenomic Permutator (MetaP), which applied the Permutable MLP-like network structure to capture the phylogenetic information of microbes within the 2D matrix formed by phylogenetic tree. Our experiments demonstrate that our model achieved competitive performance compared to other deep neural networks and traditional machine learning, and has good prospects for multi-classification and large sample sizes. Furthermore, we utilize the SHAP (SHapley Additive exPlanations) method to interpret our model predictions, identifying the microbial features that are associated with diseases.
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Microbioma Gastrointestinal , Metagenômica , Metagenômica/métodos , Microbioma Gastrointestinal/genética , Humanos , Redes Neurais de Computação , Filogenia , Aprendizado de Máquina , Aprendizado Profundo , Metagenoma/genéticaRESUMO
The test-negative design (TND) is a popular method for evaluating vaccine effectiveness (VE). A "classical" TND study includes symptomatic individuals tested for the disease targeted by the vaccine to estimate VE against symptomatic infection. However, recent applications of the TND have attempted to estimate VE against infection by including all tested individuals, regardless of their symptoms. In this article, we use directed acyclic graphs and simulations to investigate potential biases in TND studies of COVID-19 VE arising from the use of this "alternative" approach, particularly when applied during periods of widespread testing. We show that the inclusion of asymptomatic individuals can potentially lead to collider stratification bias, uncontrolled confounding by health and healthcare-seeking behaviors (HSBs), and differential outcome misclassification. While our focus is on the COVID-19 setting, the issues discussed here may also be relevant in the context of other infectious diseases. This may be particularly true in scenarios where there is either a high baseline prevalence of infection, a strong correlation between HSBs and vaccination, different testing practices for vaccinated and unvaccinated individuals, or settings where both the vaccine under study attenuates symptoms of infection and diagnostic accuracy is modified by the presence of symptoms.
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INTRODUCTION: Human epidermal growth factor receptor-2 (HER-2) low expression breast malignant tumors have become a research hotspot in recent years, but it is still unclear whether HER-2 low expression represents a special subtype of breast cancer. However, this molecular type requires more effective treatment regimens in the neoadjuvant therapy stage. METHODS: This study enrolled breast cancer patients who were treated at Harbin Medical University Cancer Hospital with neoadjuvant treatment between October 2011 and May 2019 and was a single-center retrospective study. RESULTS: A total of 1,053 breast cancer patients who received preoperative therapy, including 279 (26%) HER-2 low expression patients, were included in this retrospective study. The HER-2 low expression group had a higher proportion of patients under 50 years old than the other two molecular subtype groups (p = 0.047, 62.0% vs. 57.2% and 52.5%), and the percentage of patients with Ki67 index above 15% was lower than that in HER-2-negative and HER-2-positive patients (p < 0.001, 50.2% vs. 63.6% and 71.5%). Most of the patients with HER-2 low expression were hormone receptor (HR) positive (p < 0.001, 85.7% vs. 60.4% and 36.0%), and their pathologic complete response (pCR) rate after neoadjuvant therapy was significantly lower than that of HER-2-negative and HER-2-positive patients (p < 0.001, 5.7% vs. 11.8% and 20.5%). The results of the subgroup analysis showed HR-positive patients with HER-2 low expression had a lower pCR rate (p < 0.001, 4.6% vs. 14.6%) and objective response rate (p = 0.001, 77.8% vs. 91.0%) than HER-2-positive patients and had no significant difference in these rates compared to HER-2-negative patients. There were no significant differences in overall survival (OS) and disease-free survival (DFS) up to 67 months (the median follow-up time) among HER-2 low, HER-2-negative, and HER-2-positive patients. The results of Cox hazard proportional showed that the Ki67 index and T stage (T3) were independent influencing factors for DFS. In terms of OS, Ki67 index, P53, T stage, and objective response were independent influencing factors for OS in HER-2 low expression patients. CONCLUSIONS: In general, further studies are needed to confirm that HER-2 low expression is a special breast cancer molecular subtype. The efficacy of neoadjuvant therapy in patients with HER-2 low expression is relatively poor, and the efficacy of neoadjuvant therapy can predict the prognosis of patients with HER-2 low expression.
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Neoplasias da Mama , Humanos , Pessoa de Meia-Idade , Feminino , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Terapia Neoadjuvante , Antígeno Ki-67 , Estudos Retrospectivos , Receptor ErbB-2/metabolismo , Resultado do Tratamento , Prognóstico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêuticoRESUMO
Twin-field quantum key distribution (TFQKD) overcomes the linear rate-loss limit, which promises a boost of secure key rate over long distance. However, the complexity of eliminating the frequency differences between the independent laser sources hinders its practical application. We analyzed and determined the frequency stability requirements for implementing TFQKD using frequency-stabilized lasers. Based on this analysis, we proposed and demonstrated a simple and practical approach that utilizes the saturated absorption spectroscopy of acetylene as an absolute reference, eliminating the need for fast frequency locking to achieve TFQKD. Adopting the 4-intensity sending-or-not-sending TFQKD protocol, we experimentally demonstrated the TFQKD over 502, 301, and 201 km ultralow-loss optical fiber, respectively. We expect this high-performance scheme will find widespread usage in future intercity and free-space quantum communication networks.
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Toxic ginkgolic acids (GAs) are a challenge for Ginkgo biloba-related food. Although a detection method for GAs is available, bulky instruments limit the field testing of GAs. Herein, by assembling gold nanoclusters with copper tannic acid (CuTA), CuAuTA nanocomposites were designed as peroxidase mimics for the colorimetric determination of GAs. Compared with single CuTA, the obtained CuAuTA nanocomposites possessed enhanced peroxidase-like properties. Based on the inhibitory effect of GAs for the catalytic activity of CuAuTA nanozymes, CuAuTA could be utilized for the colorimetric sensing of GAs with a low limit of quantitation of 0.17 µg mL-1. Using a smartphone and the ImageJ software in conjunction, a nanozyme-based intelligent detection platform was developed with a detection limit of 0.86 µg mL-1. This sensing system exhibited good selectivity against other potential interferents. Experimental data demonstrated that GAs might bind to the surface of CuAuTA, blocking the catalytically active sites and resulting in decreased catalytic activity. Our CuAuTA nanozyme-based system could also be applied to detect real ginkgo nut and ginkgo powder samples with recoveries of 93.12-111.6% and relative standard deviations less than 0.3%. Our work may offer a feasible strategy for the determination of GAs and expand the application of nanozymes in food safety detection.
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Colorimetria , Cobre , Ginkgo biloba , Ouro , Limite de Detecção , Nanopartículas Metálicas , Salicilatos , Cobre/química , Salicilatos/química , Ouro/química , Colorimetria/métodos , Ginkgo biloba/química , Nanopartículas Metálicas/química , Taninos/química , Nanocompostos/química , CatáliseRESUMO
BACKGROUND: Achieving a pathological complete response (pCR) after neoadjuvant therapy (NAT) is considered to be a critical factor for a favourable prognosis in breast cancer. However, discordant pathological complete response (DpCR), characterised by isolated responses in the breast or axillary, represents an intermediate pathological response category between no response and complete response. This study aims to investigate predictive factors and develop models based on peripheral blood inflammatory indexes to more accurately predict NAT outcomes. METHOD: A total of 789 eligible patients were enrolled in this retrospective study. The patients were randomized into training and validation cohort according to a 7:3 ratio. Lasso and uni/multivariable logistic regression analysis were applied to identify the predictor variables. Two Nomograms combining clinico-pathologic features and peripheral blood inflammatory indexes were developed. RESULT: Molecular Subtype, HALP, P53, and FAR were used to construct the predictive models for traditional non pCR (T-NpCR) and total-pCR (TpCR). The T-NpCR group was divided into DpCR and non pCR (NpCR) subgroups to construct a new model to more accurately predict NAT outcomes. cN, HALP, FAR, Molecular Subtype, and RMC were used to construct the predictive models for NpCR and DpCR. The receiver operating characteristic (ROC) curves indicate that the model exhibits robust predictive capacity. Clinical Impact Curves (CIC) and Decision Curve Analysis (DCA) indicate that the models present a superior clinical utility. CONCLUSION: HALP and FAR were identified as peripheral blood inflammatory index predictors for accurately predicting NAT outcomes.
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Neoplasias da Mama , Terapia Neoadjuvante , Nomogramas , Humanos , Feminino , Terapia Neoadjuvante/métodos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/sangue , Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto , Inflamação/sangue , Prognóstico , Resultado do Tratamento , Valor Preditivo dos TestesRESUMO
BACKGROUND: In small cell lung cancer (SCLC), the pathological N category is identical to it in non-small cell lung cancer (NSCLC) and remains unchanged over a decade. Here we verified the discriminability of number of involved nodal stations (nS) in SCLC and compared its efficacy in predicting survival with currently used pathological nodal (pN) staging. METHODS: We retrospectively analyzed the patients who received operations and were pathologically diagnosed as SCLC at Shanghai Pulmonary Hospital between 2009 and 2019. X-tile software was adopted to determine optimal cut-off values for nS groups. Kaplan-Meier method and Cox regression analysis were used to compare survival between different groups. Decision curve analysis (DCA) was employed to evaluate the standardized net benefit. RESULTS: A total of 369 patients were included. The median number of sampled stations was 6 (range 3-11), and the median number of positive stations was 1 (range 0-7). The optimal cutoff for nS groups was: nS0 (no station involved), nS1-2 (one or two stations involved), and nS ≥ 3 (three or more stations involved). Overall survival (OS) and relapse-free survival (RFS) were statistically different among all adjacent categories within the nS classification (p < 0.001, for both OS and RFS between each two subgroups), but survival curves for subgroups in pN overlapped (OS, p = 0.067; RFS, p = 0.068, pN2 vs. pN1). After adjusting for other confounders, nS was a prognostic indicator for OS and RFS. The DCA revealed that nS had improved predictive capability than pN. CONCLUSIONS: Our cohort study demonstrated that the nS might serve as a superior indicator to predict survival than pN in SCLC and was worth considering in the future definition of the N category.
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Neoplasias Pulmonares , Estadiamento de Neoplasias , Carcinoma de Pequenas Células do Pulmão , Humanos , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Feminino , Estudos Retrospectivos , Carcinoma de Pequenas Células do Pulmão/mortalidade , Carcinoma de Pequenas Células do Pulmão/patologia , Idoso , Estimativa de Kaplan-Meier , China/epidemiologia , Adulto , Linfonodos/patologia , Idoso de 80 Anos ou mais , Prognóstico , Metástase Linfática , Modelos de Riscos ProporcionaisRESUMO
OBJECTIVES: To enhance the de novo synthesis of SAM, the effects of several key genes on SAM synthesis were examined based on modular strategy, and the key genes were manipulated to obtain an engineered strain with high SAM production. RESULTS: In Bacillus amyloliquefaciens HSAM6, the deletion of argG gene to block aspartic acid branching degradation increased SAM titer to 254.78 ± 15.91 mg/L, up 18% from HSAM6. Subsequently, deleting the moaA gene to boost the supply of 5-methyltetrahydrofolate led to the stunted growth and the plummeting yield of SAM. Further improvement of strain growth by overexpression of the citA gene, while SAM synthesis was not significantly enhanced. Finally, the maximum SAM titer (452.89 ± 13.42 mg/L) was obtained by overexpression SAM2 gene using the multicopy plasmid. CONCLUSIONS: The deletion of argG gene and the overexpression of SAM2 gene significantly improved SAM synthesis in B. amyloliquefaciens.
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By self-assembly of MnCl2 and arginine under alkaline conditions, ultra-small MnArg nanoparticles were successfully constructed as oxidase (OXD) mimics for intelligent detection of the Ginkgo toxin 4'-O-methylpyridoxal (MPN). The obtained MnArg nanozymes possessed excellent OXD-like activity and thermal stability. Based on the inhibitory effect of MPN for the catalytic activity of MnArg, this system was utilized for the colorimetric sensing of MPN with a low limit of detection (LOD) of 2.16 µg mL-1. The detection system exhibited good selectivity against other potential interferents. FTIR data showed that the presence of MPN binds with MnArg and shields the active sites, thereby interfering with the oxidase-like activity. Combined with a smartphone and the ColorMax software, this nanozyme-based intelligent detection platform could effectively detect MPN with a LOD of 2.1 µg mL-1. Our MnArg nanozyme-based system was applied to detect real ginkgo nut samples with recoveries of 92.4-108.7%, and the relative standard deviations were less than 0.7%. This work may promote the development of novel nanozymes and expand their applications in the field of food safety detection.
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Arginina , Colorimetria , Ginkgo biloba , Limite de Detecção , Manganês , Oxirredutases , Smartphone , Arginina/química , Arginina/análogos & derivados , Colorimetria/métodos , Manganês/química , Oxirredutases/química , Oxirredutases/metabolismo , Ginkgo biloba/química , Materiais Biomiméticos/química , Nanopartículas/químicaRESUMO
We demonstrate an efficient wavelength-selectable output in the attractive deep-red spectral region from an intracavity frequency converted Nd:YLF/KGW Raman laser. Driven by an acousto-optic Q-switched 1314â nm Nd:YLF laser, two first-Stokes waves at 1461 and 1490â nm were generated owing to the bi-axial properties of KGW crystal. By incorporating intracavity sum-frequency generation and second-harmonic generation with an angle-tuned bismuth borate (BIBO) crystal, four discrete deep-red laser emission lines were yielded at the wavelengths of 692, 698, 731, and 745â nm. Under the incident pump power of 50 W and the repetition rate of 4 kHz, the maximum average output powers of 2.4, 2.7, 3.3, and 3.6 W were attained with the pulse durations of 3.4, 3.2, 4.3, and 3.7â ns, respectively, corresponding to the peak powers up to 177, 209, 190, and 245â kW. The results indicate that the Nd:YLF/KGW Raman laser combined with an angle-adjusted BIBO crystal provides a reliable and convenient approach to achieve the selectable multi-wavelength deep-red laser with short pulse duration and high peak power.
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We demonstrate the first multi-segmented Nd:YLF laser, to the best of our knowledge. The multi-segmented crystal was designed to straightforwardly aim for the minimum thermal stress without sacrificing the overall laser efficiency, with the influence of the pump beam waist position considered in particular. Integrating the enhanced thermo-mechanical resistance of multi-segmented crystal and the alleviated heat load of low quantum defect pumping, this end-pumped 1314â nm Nd:YLF laser system delivered a maximum continuous-wave output power of up to 35.5 W under a pump power of 105 W, corresponding to an optical-to-optical efficiency of 33.8%. Furthermore, by incorporating an acousto-optic modulator, an active Q-switching oscillator was accomplished, yielding a maximum average output power of 22.9 W at a pulse repetition frequency (PRF) of 20 kHz and a largest pulse energy of 13.6 mJ at a PRF of 1 kHz.
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Twin-field quantum key distribution (TF-QKD) has emerged as a promising solution for practical quantum communication over long-haul fiber. However, previous demonstrations on TF-QKD require the phase locking technique to coherently control the twin light fields, inevitably complicating the system with extra fiber channels and peripheral hardware. Here, we propose and demonstrate an approach to recover the single-photon interference pattern and realize TF-QKD without phase locking. Our approach separates the communication time into reference frames and quantum frames, where the reference frames serve as a flexible scheme for establishing the global phase reference. To do so, we develop a tailored algorithm based on fast Fourier transform to efficiently reconcile the phase reference via data postprocessing. We demonstrate no-phase-locking TF-QKD from short to long distances over standard optical fibers. At 50-km standard fiber, we produce a high secret key rate (SKR) of 1.27 Mbit/s, while at 504-km standard fiber, we obtain the repeaterlike key rate scaling with a SKR of 34 times higher than the repeaterless secret key capacity. Our work provides a scalable and practical solution to TF-QKD, thus representing an important step towards its wide applications.