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Naturally occurring (native) sugars and carbohydrates contain numerous hydroxyl groups of similar reactivity1,2. Chemists, therefore, rely typically on laborious, multi-step protecting-group strategies3 to convert these renewable feedstocks into reagents (glycosyl donors) to make glycans. The direct transformation of native sugars to complex saccharides remains a notable challenge. Here we describe a photoinduced approach to achieve site- and stereoselective chemical glycosylation from widely available native sugar building blocks, which through homolytic (one-electron) chemistry bypasses unnecessary hydroxyl group masking and manipulation. This process is reminiscent of nature in its regiocontrolled generation of a transient glycosyl donor, followed by radical-based cross-coupling with electrophiles on activation with light. Through selective anomeric functionalization of mono- and oligosaccharides, this protecting-group-free 'cap and glycosylate' approach offers straightforward access to a wide array of metabolically robust glycosyl compounds. Owing to its biocompatibility, the method was extended to the direct post-translational glycosylation of proteins.
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Técnicas de Química Sintética , Oligosacáridos , Azúcares , Radicales Libres/química , Radicales Libres/metabolismo , Glicosilación/efectos de la radiación , Indicadores y Reactivos/química , Luz , Oligosacáridos/síntesis química , Oligosacáridos/química , Oligosacáridos/metabolismo , Oligosacáridos/efectos de la radiación , Estereoisomerismo , Azúcares/síntesis química , Azúcares/química , Azúcares/metabolismo , Azúcares/efectos de la radiaciónRESUMEN
The mechanism by which cells decide to skip mitosis to become polyploid is largely undefined. Here we used a high-content image-based screen to identify small-molecule probes that induce polyploidization of megakaryocytic leukemia cells and serve as perturbagens to help understand this process. Our study implicates five networks of kinases that regulate the switch to polyploidy. Moreover, we find that dimethylfasudil (diMF, H-1152P) selectively increased polyploidization, mature cell-surface marker expression, and apoptosis of malignant megakaryocytes. An integrated target identification approach employing proteomic and shRNA screening revealed that a major target of diMF is Aurora kinase A (AURKA). We further find that MLN8237 (Alisertib), a selective inhibitor of AURKA, induced polyploidization and expression of mature megakaryocyte markers in acute megakaryocytic leukemia (AMKL) blasts and displayed potent anti-AMKL activity in vivo. Our findings provide a rationale to support clinical trials of MLN8237 and other inducers of polyploidization and differentiation in AMKL.
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Azepinas/farmacología , Descubrimiento de Drogas , Leucemia Megacarioblástica Aguda/tratamiento farmacológico , Megacariocitos/metabolismo , Poliploidía , Pirimidinas/farmacología , Bibliotecas de Moléculas Pequeñas , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/análogos & derivados , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/farmacología , Animales , Aurora Quinasa A , Aurora Quinasas , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Humanos , Leucemia Megacarioblástica Aguda/genética , Megacariocitos/citología , Megacariocitos/patología , Ratones , Ratones Endogámicos C57BL , Mapas de Interacción de Proteínas , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/metabolismo , Quinasas Asociadas a rho/metabolismoRESUMEN
Desired fertility measures are routinely collected and used by researchers and policy makers, but their self-reported nature raises the possibility of reporting bias. In this paper, we test for the presence of such bias by comparing responses to direct survey questions with indirect questions offering a varying, randomized, degree of confidentiality to respondents in a socioeconomically diverse sample of Nigerian women ([Formula: see text]). We find that women report higher fertility preferences when asked indirectly, but only when their responses afford them complete confidentiality, not when their responses are simply blind to the enumerator. Our results suggest that there may be fewer unintended pregnancies than currently thought and that the effectiveness of family planning policy targeting may be weakened by the bias we uncover. We conclude with suggestions for future work on how to mitigate reporting bias.
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Sesgo , Fertilidad , Autoinforme , Humanos , Femenino , Adulto , Nigeria , EmbarazoRESUMEN
Peroxidase-like catalysts are safe and low-cost candidates to tackle the dilemma in constructing sustainable cathodic heterogeneous electro-Fenton (CHEF) catalysts for water purification, but the elusive structure-property relationship of enzyme-like catalysts constitutes a pressing challenge for the advancement of CHEF processes in practically relevant water and wastewater treatment. Herein, we probe the origins of catalytic efficiency in the CHEF process by artificially tailoring the peroxidase-like activity of Fe3O4 through a series of acetylated chitosan-based hydrogels, which serve as ecofriendly alternatives to traditional carbon shells. The optimized acetylated chitosan wrapping Fe3O4 hydrogel on the cathode shows an impressive activity and stability in CHEF process, overcoming the complicated and environmentally unfavored procedures in the electro-Fenton-related processes. Structural characterizations and theoretical calculations reveal that the amide group in chitosan can modulate the intrinsic redox capacity of surficial Fe sites on Fe3O4 toward CHEF catalysis via the neutral hydrogen bond. This work provides a sustainable path and molecule-level insight for the rational design of high-efficiency CHEF catalysts and beyond.
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Proofreading (editing) of mischarged tRNAs by cytoplasmic aminoacyl-tRNA synthetases (aaRSs), whose impairment causes neurodegeneration and cardiac diseases, is of high significance for protein homeostasis. However, whether mitochondrial translation needs fidelity and the significance of editing by mitochondrial aaRSs have been unclear. Here, we show that mammalian cells critically depended on the editing of mitochondrial threonyl-tRNA synthetase (mtThrRS, encoded by Tars2), disruption of which accumulated Ser-tRNAThr and generated a large abundance of Thr-to-Ser misincorporated peptides in vivo. Such infidelity impaired mitochondrial translation and oxidative phosphorylation, causing oxidative stress and cell cycle arrest in the G0/G1 phase. Notably, reactive oxygen species (ROS) scavenging by N-acetylcysteine attenuated this abnormal cell proliferation. A mouse model of heart-specific defective mtThrRS editing was established. Increased ROS levels, blocked cardiomyocyte proliferation, contractile dysfunction, dilated cardiomyopathy, and cardiac fibrosis were observed. Our results elucidate that mitochondria critically require a high level of translational accuracy at Thr codons and highlight the cellular dysfunctions and imbalance in tissue homeostasis caused by mitochondrial mistranslation.
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Aminoacil-ARNt Sintetasas , Cardiomiopatías , Cardiopatías , Animales , Ratones , Especies Reactivas de Oxígeno , Puntos de Control del Ciclo Celular , Estrés Oxidativo , MamíferosRESUMEN
Plasma membrane (PM)-associated abscisic acid (ABA) signal transduction is an important component of ABA signaling. The C2-domain ABA-related (CAR) proteins have been reported to play a crucial role in recruiting ABA receptor PYR1/PYL/RCAR (PYLs) to the PM. However, the molecular details of the involvement of CAR proteins in membrane-delimited ABA signal transduction remain unclear. For instance, where this response process takes place and whether any additional members besides PYL are taking part in this signaling process. Here, the GUS-tagged materials for all Arabidopsis CAR members were used to comprehensively visualize the extensive expression patterns of the CAR family genes. Based on the representativeness of CAR1 in response to ABA, we determined to use it as a target to study the function of CAR proteins in PM-associated ABA signaling. Single-particle tracking showed that ABA affected the spatiotemporal dynamics of CAR1. The presence of ABA prolonged the dwell time of CAR1 on the membrane and showed faster lateral mobility. Surprisingly, we verified that CAR1 could directly recruit hypersensitive to ABA1 (HAB1) and SNF1-related protein kinase 2.2 (SnRK2.2) to the PM at both the bulk and single-molecule levels. Furthermore, PM localization of CAR1 was demonstrated to be related to membrane microdomains. Collectively, our study revealed that CARs recruited the three main components of ABA signaling to the PM to respond positively to ABA. This study deepens our understanding of ABA signal transduction.
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Ácido Abscísico , Proteínas de Arabidopsis , Arabidopsis , Membrana Celular , Proteínas Serina-Treonina Quinasas , Transducción de Señal , Ácido Abscísico/metabolismo , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Membrana Celular/metabolismo , Regulación de la Expresión Génica de las Plantas , Reguladores del Crecimiento de las Plantas/metabolismo , Plantas Modificadas Genéticamente , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genéticaRESUMEN
Drought is a major adverse environmental factor that plants face in nature but the molecular mechanism by which plants transduce stress signals and further endow themselves with tolerance remains unclear. Malectin/malectin-like domains containing receptor-like kinases (MRLKs) have been proposed to act as receptors in multiple biological signaling pathways, but limited studies show their roles in drought-stress signaling and tolerance. In this study, we demonstrate OsMRLK63 in rice (Oryza sativa L.) functions in drought tolerance by acting as the receptor of 2 rapid alkalization factors, OsRALF45 and OsRALF46. We show OsMRLK63 is a typical receptor-like kinase that positively regulates drought tolerance and reactive oxygen species (ROS) production. OsMRLK63 interacts with and phosphorylates several nicotinamide adenine dinucleotide phosphate (NADPH) oxidases with the primarily phosphorylated site at Ser26 in the N-terminal of RESPIRATORY BURST OXIDASE HOMOLOGUE A (OsRbohA). The application of the 2 small signal peptides (OsRALF45/46) on rice can greatly alleviate the dehydration of plants induced by mimic drought. This function depends on the existence of OsMRLK63 and the NADPH oxidase-dependent ROS production. The 2 RALFs interact with OsMRLK63 by binding to its extracellular domain, suggesting they may act as drought/dehydration signal sensors for the OsMRLK63-mediated process. Our study reveals a OsRALF45/46-OsMRLK63-OsRbohs module which contributes to drought-stress signaling and tolerance in rice.
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Oryza , Especies Reactivas de Oxígeno/metabolismo , Oryza/metabolismo , Resistencia a la Sequía , Deshidratación , Estrés Fisiológico , Plantas Modificadas Genéticamente/metabolismo , Sequías , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
Esophageal squamous cell carcinoma (ESCC) is an aggressive malignant disease with a poor prognosis. We previously found that p62 presented a marked nuclear-cytoplasmic translocation in ESCC cells as compared that in normal esophageal epithelial cells, but its effects on ESCC cells remain unclear. This study aims to clarify the impacts of different cellular localization of p62 on the function of ESCC cells and the underlying molecular mechanisms. We here demonstrated that cytoplasmic p62 enhances the migration and invasion abilities of esophageal cancer cells, whereas nuclear p62 has no effect. We further explored the interaction protein of p62 by using GST pull-down experiment and identified EPLIN as a potential protein interacting with p62. In addition, reducing EPLIN expression significantly inhibited the migration and invasion of ESCC cells, which were rescued when EPLIN expression was restored after the p62 knockdown. At a molecular level, p62 in cytoplasm positively regulated the expression of EPLIN via enhancing its protein stability. Data from the TCGA and GEO database displayed a significant up-regulation of EPLIN mRNA expression in ESCC tissues compared with corresponding paired esophageal epithelial samples. Our findings present evidence that the nuclear-cytoplasmic translocation of p62 protein contributes to an aggressive malignancy phenotype, providing candidate molecular biomarkers and potential molecular targets for the diagnosis and treatment of ESCC.
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Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Humanos , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular , Citoplasma/metabolismo , Neoplasias Esofágicas/patología , Carcinoma de Células Escamosas de Esófago/patología , Regulación Neoplásica de la Expresión Génica/genética , Invasividad Neoplásica/genética , Proteína Sequestosoma-1/genética , Proteína Sequestosoma-1/metabolismoRESUMEN
Pyridine, a widespread aromatic heterocycle, features a sp2-hybridized nitrogen atom that can readily coordinate to metals, leading to distinctive achievements in catalysis. In stark contrast, π-coordination of pyridine and derivatives with transition metals is notably scarce, and the involvement of such activation mode in catalysis remains to be developed. Herein, we present amination reactions of aminopyridines that leverages the reversible π coordination with a ruthenium catalyst as the arenophilic π acid, rather than relying on the conventional κ-N coordination. Specifically, a transient η6-pyridine complex functions as the electrophile in the nucleophilic aromatic substitution with amines, providing a diverse array of products via the cleavage of the pyridyl C-N bond. In addition, this method can be employed to incorporate chiral amines and 15N-labeled amines.
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HIV-1 is a highly host-specific retrovirus that infects humans but not most nonhuman primates. Thus, the lack of a suitable primate model that can be directly infected with HIV-1 hinders HIV-1/AIDS research. In the previous study, we have found that the northern pig-tailed macaques (NPMs) are susceptible to HIV-1 infection but show a nonpathogenic state. In this study, to understand this macaque-HIV-1 interaction, we assembled a de novo genome and longitudinal transcriptome for this species during the course of HIV-1 infection. Using comparative genomic analysis, a positively selected gene, Toll-like receptor 8, was identified with a weak ability to induce an inflammatory response in this macaque. In addition, an interferon-stimulated gene, interferon alpha inducible protein 27, was upregulated in acute HIV-1 infection and acquired an enhanced ability to inhibit HIV-1 replication compared with its human ortholog. These findings coincide with the observation of persistently downregulated immune activation and low viral replication and can partially explain the AIDS-free state in this macaque following HIV-1 infection. This study identified a number of unexplored host genes that may hamper HIV-1 replication and pathogenicity in NPMs and provided new insights into the host defense mechanisms in cross-species infection of HIV-1. This work will facilitate the adoption of NPM as a feasible animal model for HIV-1/AIDS research.
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Infecciones por VIH , VIH-1 , Virus de la Inmunodeficiencia de los Simios , Animales , Humanos , Macaca nemestrina , VIH-1/genética , Genómica , Virus de la Inmunodeficiencia de los Simios/genéticaRESUMEN
TARS2 encodes human mitochondrial threonyl tRNA-synthetase that is responsible for generating mitochondrial Thr-tRNAThr and clearing mischarged Ser-tRNAThr during mitochondrial translation. Pathogenic variants in TARS2 have hitherto been reported in a pair of siblings and an unrelated patient with an early onset mitochondrial encephalomyopathy and a combined respiratory chain enzyme deficiency in muscle. We here report five additional unrelated patients with TARS2-related mitochondrial diseases, expanding the clinical phenotype to also include epilepsy, dystonia, hyperhidrosis and severe hearing impairment. In addition, we document seven novel TARS2 variants-one nonsense variant and six missense variants-that we demonstrate are pathogenic and causal of the disease presentation based on population frequency, homology modeling and functional studies that show the effects of the pathogenic variants on TARS2 stability and/or function.
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Enfermedades Mitocondriales , Encefalomiopatías Mitocondriales , Treonina-ARNt Ligasa , Humanos , Enfermedades Mitocondriales/genética , Enfermedades Mitocondriales/patología , Encefalomiopatías Mitocondriales/genética , Mutación , Fenotipo , ARN de Transferencia de Treonina/genética , Treonina-ARNt Ligasa/genéticaRESUMEN
Vanadium oxides have aroused attention as cathode materials in aqueous zinc-ion batteries (AZIBs) due to their low cost and high safety. However, low ion diffusion and vanadium dissolution often lead to capacity decay and deteriorating stability during cycling. Herein, vanadium dioxides (VO2) nanobelts are coated with a single-atom cobalt dispersed N-doped carbon (Co-N-C) layer via a facile calcination strategy to form Co-N-C layer coated VO2 nanobelts (VO2@Co-N-C NBs) for cathodes in AZIBs. Various in-/ex situ characterizations demonstrate the interfaces between VO2 layers and Co-N-C layers can protect the VO2 NBs from collapsing, increase ion diffusion, and enhance the Zn2+ storage performance. Additional density functional theory (DFT) simulations demonstrate that CoâOâV bonds between VO2 and Co-N-C layers can enhance interfacial Zn2+ storage. Moreover, the VO2@Co-N-C NBs provided an ultrahigh capacity (418.7 mAh g-1 at 1 A g-1), outstanding long-term stability (over 8000 cycles at 20 A g-1), and superior rate performance.
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Tetherin prevents viral cross-species transmission by inhibiting the release of multiple enveloped viruses from infected cells. With the evolution of simian immunodeficiency virus of chimpanzees (SIVcpz), a pandemic human immunodeficiency virus type 1 (HIV-1) precursor, its Vpu protein can antagonize human tetherin (hTetherin). Macaca leonina (northern pig-tailed macaque [NPM]) is susceptible to HIV-1, but host-specific restriction factors limit virus replication in vivo. In this study, we isolated the virus from NPMs infected with strain stHIV-1sv (with a macaque-adapted HIV-1 env gene from simian-human immunodeficiency virus SHIV-KB9, a vif gene replaced by SIVmac239, and other genes originating from HIV-1NL4.3) and found that a single acidic amino acid substitution (G53D) in Vpu could increase its ability to degrade the tetherin of macaques (mTetherin) mainly through the proteasome pathway, resulting in an enhanced release and resistance to interferon inhibition of the mutant stHIV-1sv strain, with no influence on the other functions of Vpu. IMPORTANCE HIV-1 has obvious host specificity, which has greatly hindered the construction of animal models and severely restricted the development of HIV-1 vaccines and drugs. To overcome this barrier, we attempted to isolate the virus from NPMs infected with stHIV-1sv, search for a strain with an adaptive mutation in NPMs, and develop a more appropriate nonhuman primate model of HIV-1. This is the first report identifying HIV-1 adaptations in NPMs. It suggests that while tetherin may limit HIV-1 cross-species transmission, the Vpu protein in HIV-1 can overcome this species barrier through adaptive mutation, increasing viral replication in the new host. This finding will be beneficial to building an appropriate animal model for HIV-1 infection and promoting the development of HIV-1 vaccines and drugs.
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Antígeno 2 del Estroma de la Médula Ósea , VIH-1 , Macaca , Proteínas Virales , Liberación del Virus , VIH-1/genética , VIH-1/patogenicidad , Proteínas Virales/genética , Proteínas Virales/metabolismo , Mutación , Antígeno 2 del Estroma de la Médula Ósea/metabolismo , Ubiquitina/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Liberación del Virus/genética , Sustitución de Aminoácidos/genética , Infecciones por VIH/virología , Modelos Animales de Enfermedad , Replicación Viral/genéticaRESUMEN
IMPORTANCE: Many plant viruses are transmitted by insect vectors in a circulative manner. For efficient transmission, the entry of the virus from vector hemolymph into the primary salivary gland (PSG) is a step of paramount importance. Yet, vector components mediating virus entry into PSG remain barely characterized. Here, we demonstrate the role of clathrin-mediated endocytosis and early endosomes in begomovirus entry into whitefly PSG. Our findings unravel the key components involved in begomovirus transport within the whitefly body and transmission by their whitefly vectors and provide novel clues for blocking begomovirus transmission.
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Begomovirus , Endocitosis , Hemípteros , Animales , Begomovirus/fisiología , Clatrina/metabolismo , Endosomas , Hemípteros/metabolismo , Hemípteros/virología , Enfermedades de las Plantas , Glándulas Salivales/metabolismo , Glándulas Salivales/virologíaRESUMEN
BACKGROUND: This study developed a nomogram model using CT-based delta-radiomics features and clinical factors to predict pathological complete response (pCR) in esophageal squamous cell carcinoma (ESCC) patients receiving neoadjuvant chemoradiotherapy (nCRT). METHODS: The study retrospectively analyzed 232 ESCC patients who underwent pretreatment and post-treatment CT scans. Patients were divided into training (n = 186) and validation (n = 46) sets through fivefold cross-validation. 837 radiomics features were extracted from regions of interest (ROIs) delineations on CT images before and after nCRT to calculate delta values. The LASSO algorithm selected delta-radiomics features (DRF) based on classification performance. Logistic regression constructed a nomogram incorporating DRFs and clinical factors. Receiver operating characteristic (ROC) and area under the curve (AUC) analyses evaluated nomogram performance for predicting pCR. RESULTS: No significant differences existed between the training and validation datasets. The 4-feature delta-radiomics signature (DRS) demonstrated good predictive accuracy for pCR, with α-binormal-based and empirical AUCs of 0.871 and 0.869. T-stage (p = 0.001) and differentiation degree (p = 0.018) were independent predictors of pCR. The nomogram combined the DRS and clinical factors improved the classification performance in the training dataset (AUCαbin = 0.933 and AUCemp = 0.941). The validation set showed similar performance with AUCs of 0.958 and 0.962. CONCLUSIONS: The CT-based delta-radiomics nomogram model with clinical factors provided high predictive accuracy for pCR in ESCC patients after nCRT.
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Quimioradioterapia , Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Terapia Neoadyuvante , Nomogramas , Curva ROC , Tomografía Computarizada por Rayos X , Humanos , Masculino , Femenino , Persona de Mediana Edad , Carcinoma de Células Escamosas de Esófago/terapia , Carcinoma de Células Escamosas de Esófago/diagnóstico por imagen , Carcinoma de Células Escamosas de Esófago/patología , Neoplasias Esofágicas/terapia , Neoplasias Esofágicas/patología , Neoplasias Esofágicas/diagnóstico por imagen , Resultado del Tratamiento , Anciano , Carcinoma de Células Escamosas/terapia , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/diagnóstico por imagen , Reproducibilidad de los Resultados , Adulto , Área Bajo la Curva , Estudios Retrospectivos , RadiómicaRESUMEN
After double fertilization, zygotic embryogenesis initiates a new life cycle, and stem cell homeostasis in the shoot apical meristem (SAM) and root apical meristem (RAM) allows plants to produce new tissues and organs continuously. Here, we report that mutations in DEAD-BOX RNA HELICASE 27 (RH27) affect zygote division and stem cell homeostasis in Arabidopsis (Arabidopsis thaliana). The strong mutant allele rh27-1 caused a zygote-lethal phenotype, while the weak mutant allele rh27-2 led to minor defects in embryogenesis and severely compromised stem cell homeostasis in the SAM and RAM. RH27 is expressed in embryos from the zygote stage, and in both the SAM and RAM, and RH27 is a nucleus-localized protein. The expression levels of genes related to stem cell homeostasis were elevated in rh27-2 plants, alongside down-regulation of their regulatory microRNAs (miRNAs). Further analyses of rh27-2 plants revealed reduced levels of a large subset of miRNAs and their pri-miRNAs in shoot apices and root tips. In addition, biochemical studies showed that RH27 associates with pri-miRNAs and interacts with miRNA-biogenesis components, including DAWDLE, HYPONASTIC LEAVES 1, and SERRATE. Therefore, we propose that RH27 is a component of the microprocessor complex and is critical for zygote division and stem cell homeostasis.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Núcleo Celular/genética , Núcleo Celular/metabolismo , Desarrollo Embrionario/genética , Desarrollo Embrionario/fisiología , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , MicroARNs/metabolismo , Cigoto/metabolismoRESUMEN
The practical utilization of the hydrogen evolution reaction (HER) necessitates the creation of electrocatalysts that are both efficient and abundant in earth elements, capable of operating effectively within a wide pH range. However, this objective continues to present itself as an arduous obstacle. In this research, we propose the incorporation of sulfur vacancies in a novel heterojunction formed by MoS2@CoS2, designed to exhibit remarkable catalytic performances. This efficacy is attributed to the advantageous combination of the low work function and space charge zone at the interface between MoS2 and CoS2 in the heterojunction. The MoS2@CoS2 heterojunction manifests outstanding hydrogen evolution activity over an extensive pH range. Remarkably, achieving a current density of 10 mA cm-2 in aqueous solutions 1.0 M KOH, 0.5 M H2SO4, and 1.0 M phosphate-buffered saline (PBS), respectively, requires only an overpotential of 48, 62, and 164 mV. The Tafel slopes for each case are 43, 32, and 62 mV dec-1, respectively. In this study, the synergistic effect of MoS2 and CoS2 is conducive to electron transfer, making the MoS2@CoS2 heterojunction show excellent electrocatalytic performance. The synergistic effects arising from the heterojunction and sulfur vacancy not only contribute to the observed catalytic prowess but also provide a valuable model and reference for the exploration of other efficient electrocatalysts. This research marks a significant stride toward overcoming the challenges associated with developing electrocatalysts for practical hydrogen evolution applications.
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BACKGROUND: Portal vein system thrombosis (PVST) is a potentially fatal complication after splenectomy with esophagogastric devascularization (SED) in cirrhotic patients with portal hypertension. However, the impact of portal vein velocity (PVV) on PVST after SED remains unclear. Therefore, this study aims to explore this issue. METHODS: Consecutive cirrhotic patients with portal hypertension who underwent SED at Tongji Hospital between January 2010 and June 2022 were enrolled. The patients were divided into two groups based on the presence or absence of PVST, which was assessed using ultrasound or computed tomography after the operation. PVV was measured by duplex Doppler ultrasound within one week before surgery. The independent risk factors for PVST were analyzed using univariate and multivariate logistic regression analysis. A nomogram based on these variables was developed and internally validated using 1000 bootstrap resamples. RESULTS: A total of 562 cirrhotic patients with portal hypertension who underwent SED were included, and PVST occurred in 185 patients (32.9%). Multivariate logistic regression analysis showed that PVV was the strongest independent risk factor for PVST. The incidence of PVST was significantly higher in patients with PVV ≤ 16.5 cm/s than in those with PVV > 16.5 cm/s (76.2% vs. 8.5%, p < 0.0001). The PVV-based nomogram was internally validated and showed good performance (optimism-corrected c-statistic = 0.907). Decision curve and clinical impact curve analyses indicated that the nomogram provided a high clinical benefit. CONCLUSION: A nomogram based on PVV provided an excellent preoperative prediction of PVST after splenectomy with esophagogastric devascularization.
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Hipertensión Portal , Trombosis de la Vena , Humanos , Vena Porta/patología , Esplenectomía/efectos adversos , Cirrosis Hepática/cirugía , Complicaciones Posoperatorias/diagnóstico por imagen , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Trombosis de la Vena/diagnóstico por imagen , Trombosis de la Vena/etiología , Hipertensión Portal/cirugía , Hipertensión Portal/complicacionesRESUMEN
Mitochondrial translation is of high significance for cellular energy homeostasis. Aminoacyl-tRNA synthetases (aaRSs) are crucial translational components. Mitochondrial aaRS variants cause various human diseases. However, the pathogenesis of the vast majority of these diseases remains unknown. Here, we identified two novel SARS2 (encoding mitochondrial seryl-tRNA synthetase) variants that cause a multisystem disorder. c.654-14T > A mutation induced mRNA mis-splicing, generating a peptide insertion in the active site; c.1519dupC swapped a critical tRNA-binding motif in the C-terminus due to stop codon readthrough. Both mutants exhibited severely diminished tRNA binding and aminoacylation capacities. A marked reduction in mitochondrial tRNASer(AGY) was observed due to RNA degradation in patient-derived induced pluripotent stem cells (iPSCs), causing impaired translation and comprehensive mitochondrial function deficiencies. These impairments were efficiently rescued by wild-type SARS2 overexpression. Either mutation caused early embryonic fatality in mice. Heterozygous mice displayed reduced muscle tissue-specific levels of tRNASers. Our findings elucidated the biochemical and cellular consequences of impaired translation mediated by SARS2, suggesting that reduced abundance of tRNASer(AGY) is a key determinant for development of SARS2-related diseases.
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Aminoacil-ARNt Sintetasas , COVID-19 , Serina-ARNt Ligasa , Humanos , Ratones , Animales , ARN de Transferencia de Serina/genética , Serina-ARNt Ligasa/genética , Serina-ARNt Ligasa/metabolismo , Aminoacil-ARNt Sintetasas/genética , AminoacilaciónRESUMEN
5-Methyl-cytosine (5mC) is one of the most important DNA modifications and plays versatile biological roles. It is well known that 5mC stabilizes DNA duplexes. However, it remains unclear how 5mC affects the kinetics of DNA melting and hybridization. Here, we studied the kinetics of unzipping and rezipping using a 502-bp DNA hairpin by single-molecule magnetic tweezers. Under constant loading rates, 5mC increases the unzipping force but counterintuitively decreases the rezipping force at various salt and temperature conditions. Under constant forces, the non-methylated DNA hops between metastable states during unzipping and rezipping, which implies low energy barriers. Surprisingly, the 5mC DNA can't rezip after fully unzipping unless much lower forces are applied, where it rezips stochastically in a one-step manner, which implies 5mC kinetically hinders DNA hybridization and high energy barriers in DNA hybridization. All-atom molecular dynamics simulations reveal that the 5mC kinetically hinders DNA hybridization due to steric effects rather than electrostatic effects caused by the additional methyl groups of cytosines. Considering the possible high speed of DNA unzipping and zipping during replication and transcription, our findings provide new insights into the biological roles of 5mC.