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The prevailing approach to addressing secondary drug resistance in cancer focuses on treating the resistance mechanisms at relapse. However, the dynamic nature of clonal evolution, along with potential fitness costs and cost compensations, may present exploitable vulnerabilities-a notion that we term "temporal collateral sensitivity." Using a combined pharmacological screen and drug resistance selection approach in a murine model of Ph(+) acute lymphoblastic leukemia, we indeed find that temporal and/or persistent collateral sensitivity to non-classical BCR-ABL1 drugs arises in emergent tumor subpopulations during the evolution of resistance toward initial treatment with BCR-ABL1-targeted inhibitors. We determined the sensitization mechanism via genotypic, phenotypic, signaling, and binding measurements in combination with computational models and demonstrated significant overall survival extension in mice. Additional stochastic mathematical models and small-molecule screens extended our insights, indicating the value of focusing on evolutionary trajectories and pharmacological profiles to identify new strategies to treat dynamic tumor vulnerabilities.
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Resistencia a Antineoplásicos , Modelos Biológicos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Animales , Ensayos de Selección de Medicamentos Antitumorales , Ratones , Cromosoma Filadelfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Proteínas Proto-Oncogénicas c-bcr/análisis , Proteínas Proto-Oncogénicas c-bcr/genéticaRESUMEN
Global warming during the Last Glacial Termination was interrupted by millennial-scale cool intervals such as the Younger Dryas and the Antarctic Cold Reversal (ACR). Although these events are well characterized at high latitudes, their impacts at low latitudes are less well known. We present high-resolution temperature and hydroclimate records from the tropical Andes spanning the past ~16,800 y using organic geochemical proxies applied to a sediment core from Laguna Llaviucu, Ecuador. Our hydroclimate record aligns with records from the western Amazon and eastern and central Andes and indicates a dominant long-term influence of changing austral summer insolation on the intensity of the South American Summer Monsoon. Our temperature record indicates a ~4 °C warming during the glacial termination, stable temperatures in the early to mid-Holocene, and slight, gradual warming since ~6,000 y ago. Importantly, we observe a ~1.5 °C cold reversal coincident with the ACR. These data document a temperature change pattern during the deglaciation in the tropical Andes that resembles temperatures at high southern latitudes, which are thought to be controlled by radiative forcing from atmospheric greenhouse gases and changes in ocean heat transport by the Atlantic meridional overturning circulation.
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Chalcogenide perovskites are a class of materials with electronic and optoelectronic properties desirable for solar cells, infrared optics, and computing. The oxide counterparts of these chalcogenides have been studied extensively for their electrocatalytic and photoelectrochemical properties. As chalcogenide perovskites are more covalent, conductive, and stable, we hypothesize that they are more viable as electrocatalysts than oxide perovskites. The goal of this synthetic, experimental, and computational study is to examine the hydrogen evolution reaction (HER) activity of three Barium-based chalcogenides in perovskite and related structures: BaZrS3, BaTiS3, and BaVS3. Potential energy surfaces for hydrogen adsorption on surfaces of these materials are calculated using density functional theory and the computational hydrogen electrode model is used to contrast overpotentials with experiment. Although both experiments and computations agree that BaVS3 is the most active of the three materials, high overpotentials of these materials make them less viable than platinum for HER. Our work establishes a framework for future studies in the chemical and electrochemical properties of chalcogenide perovskites.
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Enteroaggregative Escherichia coli (EAEC) is a significant cause of acute and chronic diarrhea, foodborne outbreaks, infections of the immunocompromised, and growth stunting in children in developing nations. There is no vaccine and resistance to antibiotics is rising. Unlike related E. coli pathotypes that are often associated with acute bouts of infection, EAEC is associated with persistent diarrhea and subclinical long-term colonization. Several secreted virulence factors have been associated with EAEC pathogenesis and linked to disease in humans, less certain are the molecular drivers of adherence to the intestinal mucosa. We previously established human intestinal enteroids (HIEs) as a model system to study host-EAEC interactions and aggregative adherence fimbriae A (AafA) as a major driver of EAEC adherence to HIEs. Here, we report a large-scale assessment of the host response to EAEC adherence from all four segments of the intestine across at least three donor lines for five E. coli pathotypes. The data demonstrate that the host response in the duodenum is driven largely by the infecting pathotype, whereas the response in the colon diverges in a patient-specific manner. Major pathways altered in gene expression in each of the four enteroid segments differed dramatically, with responses observed for inflammation, apoptosis and an overwhelming response to different mucin genes. In particular, EAEC both associated with large mucus droplets and specific mucins at the epithelial surface, binding that was ameliorated when mucins were removed, a process dependent on AafA. Pan-screening for glycans for binding to purified AafA identified the human ligand as heparan sulfate proteoglycans (HSPGs). Removal of HSPG abrogated EAEC association with HIEs. These results may mean that the human intestine responds remarkably different to distinct pathobionts that is dependent on the both the individual and intestinal segment in question, and uncover a major role for surface heparan sulfate proteoglycans as tropism-driving factor in adherence and/or colonization.
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Adhesión Bacteriana/fisiología , Infecciones por Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteoglicanos de Heparán Sulfato/metabolismo , Adhesinas de Escherichia coli/genética , Escherichia coli/metabolismo , Fimbrias Bacterianas/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Factores de Virulencia/metabolismoRESUMEN
Chalcogenides in the perovskite and related crystal structures ("chalcogenide perovskites" for brevity) may be useful for future optoelectronic and energy-conversion technologies inasmuch as they have good excited-state, ambipolar transport properties. In recent years, several studies have suggested that semiconductors in the Ba-Zr-S system have slow non-radiative recombination rates. Here, we present a time-resolved photoluminescence (TRPL) study of excited-state carrier mobility and recombination rates in the perovskite-structured material BaZrS3, and the related Ruddlesden-Popper phase Ba3Zr2S7. We measure state-of-the-art single crystal samples, to identify properties free from the influence of secondary phases and random grain boundaries. We model and fit the data using a semiconductor physics simulation, to enable more direct determination of key material parameters than is possible with empirical data modeling. We find that both materials have Shockley-Read-Hall recombination lifetimes on the order of 50 ns and excited-state diffusion lengths on the order of 5 µm at room temperature, which bodes well for ambipolar device performance in optoelectronic technologies including thin-film solar cells.
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Many RNA viruses replicate in cytoplasmic compartments (virus factories or viroplasms) composed of viral and cellular proteins, but the mechanisms required for their formation remain largely unknown. Rotavirus (RV) replication in viroplasms requires interactions between virus nonstructural proteins NSP2 and NSP5, which are associated with components of lipid droplets (LDs). We previously identified two forms of NSP2 in RV-infected cells, a cytoplasmically dispersed form (dNSP2) and a viroplasm-specific form (vNSP2), which interact with hypophosphorylated and hyperphosphorylated NSP5, respectively, indicating that a coordinated phosphorylation cascade controls viroplasm assembly. The cellular kinase CK1α phosphorylates NSP2 on serine 313, triggering the localization of vNSP2 to sites of viroplasm assembly and its association with hyperphosphorylated NSP5. Using reverse genetics, we generated a rotavirus with a phosphomimetic NSP2 (S313D) mutation to directly evaluate the role of CK1α NSP2 phosphorylation in viroplasm formation. Recombinant rotavirus NSP2 S313D (rRV NSP2 S313D) is significantly delayed in viroplasm formation and in virus replication and interferes with wild-type RV replication in coinfection. Taking advantage of the delay in viroplasm formation, the NSP2 phosphomimetic mutant was used as a tool to observe very early events in viroplasm assembly. We show that (i) viroplasm assembly correlates with NSP5 hyperphosphorylation and (ii) vNSP2 S313D colocalizes with RV-induced LDs without NSP5, suggesting that vNSP2 phospho-S313 is sufficient for interacting with LDs and may be the virus factor required for RV-induced LD formation. Further studies with the rRV NSP2 S313D virus are expected to reveal new aspects of viroplasm and LD initiation and assembly.IMPORTANCE Reverse genetics was used to generate a recombinant rotavirus with a single phosphomimetic mutation in nonstructural protein 2 (NSP2 S313D) that exhibits delayed viroplasm formation, delayed replication, and an interfering phenotype during coinfection with wild-type rotavirus, indicating the importance of this amino acid during virus replication. Exploiting the delay in viroplasm assembly, we found that viroplasm-associated NSP2 colocalizes with rotavirus-induced lipid droplets prior to the accumulation of other rotavirus proteins that are required for viroplasm formation and that NSP5 hyperphosphorylation is required for viroplasm assembly. These data suggest that NSP2 phospho-S313 is sufficient for interaction with lipid droplets and may be the virus factor that induces lipid droplet biogenesis in rotavirus-infected cells. Lipid droplets are cellular organelles critical for the replication of many viral and bacterial pathogens, and thus, understanding the mechanism of NSP2-mediated viroplasm/lipid droplet initiation and interaction will lead to new insights into this important host-pathogen interaction.
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Gotas Lipídicas/metabolismo , Gotas Lipídicas/virología , Proteínas de Unión al ARN/metabolismo , Rotavirus/fisiología , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/fisiología , Animales , Línea Celular , Cricetinae , Fosforilación , Proteínas de Unión al ARN/genética , Proteínas no Estructurales Virales/genéticaRESUMEN
The efficient and low-cost way for gene mutation detection and identification are conducive for the detection of disease. Here, we report the electronic characteristics of the gene of breast cancer 1 in four common mutation types: duplication, single nucleotide variant, deletion, and indel. The electronic characteristics are investigated by the combination of density functional theory and non-equilibrium Green's function formulation with decoherence. The magnitude of conductance of these DNA molecules and mutational changes are found to be detectable experimentally. In this study, we also find the significant mutation type dependent on the change of conductance. Hence these mutations are expected to be identifiable. We find deletion type mutation shows the largest change in relative conductance (~97%), whereas the indel mutation shows the smallest change in relative conductance (~27%). Therefore, this work presents a possibility of electronic detection and identification of mutations in DNA, which could be an efficient method as compared to the conventional methods.
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Neoplasias de la Mama , Genes BRCA2 , Proteína BRCA1/genética , ADN/genética , Electrónica , Femenino , Genes BRCA1 , Humanos , MutaciónRESUMEN
DNA hydroxymethylation plays a very important role in some biological processes, such as DNA methylation process. In addition, its presence can also cause some diseases. In this paper, the electrical properties of cytosine hydroxymethylated (Chm) DNA sequences are studied. The density functional theory (DFT) and Landauer-Büttiker framework are used to study the decoherence conductance and transmission of the Chm strands in different configurations, which provides a theoretical basis for the detection of Chm. The results show that the conductance of the hydroxymethylated DNA strand is smaller than that of the native and methylated strands. The length dependence of the Chm strands is also studied. With the length increasing, the conductance becomes larger. This study shows that DNA methylation can be detected electrically.
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Citosina/metabolismo , Metilación de ADN , ADN/química , 5-Metilcitosina , Biofisica , Electrofisiología , Epigénesis Genética , Conformación Molecular , Solventes/química , TemperaturaRESUMEN
Household humidification is widely practiced to combat dry indoor air. While the benefits of household humidification are widely perceived, its implications to the indoor air have not been critically appraised. In particular, ultrasonic humidifiers are known to generate fine particulate matter (PM). In this study, we first conducted laboratory experiments to investigate the size, quantity, and chemical composition of PM generated by an ultrasonic humidifier. The mass of PM generated showed a correlation with the total alkalinity of charge water, suggesting that CaCO3 is likely making a major contribution to PM. Ion chromatography analysis revealed a large amount of SO42- in PM, representing a previously unrecognized indoor source. Preliminary results of organic compounds being present in humidifier PM are also presented. A whole-house experiment was further conducted at an actual residential house, with five low-cost sensors (AirBeam) monitoring PM in real time. Operation of a single ultrasonic humidifier resulted in PM2.5 concentrations up to hundreds of µg m-3 , and its influence extended across the entire household. The transport and loss of PM2.5 depended on the rate of air circulation and ventilation. This study emphasizes the need to further investigate the impact of humidifier operation, both on human health and on the indoor atmospheric chemistry, for example, partitioning of acidic and basic compounds.
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Contaminación del Aire Interior/estadística & datos numéricos , Humidificadores , Material Particulado , Contaminantes Atmosféricos , Monitoreo del Ambiente , Humanos , Compuestos Orgánicos , Tamaño de la Partícula , Ultrasonido , AguaRESUMEN
Human noroviruses (NoVs) are the main cause of epidemic and sporadic gastroenteritis. Phylogenetically, noroviruses are divided into seven genogroups, with each divided into multiple genotypes. NoVs belonging to genogroup II and genotype 4 (GII.4) are globally most prevalent. Genetic diversity among the NoVs and the periodic emergence of novel strains present a challenge for the development of vaccines and antivirals to treat NoV infection. NoV protease is essential for viral replication and is an attractive target for the development of antivirals. The available structure of GI.1 protease provided a basis for the design of inhibitors targeting the active site of the protease. These inhibitors, although potent against the GI proteases, poorly inhibit the GII proteases, for which structural information is lacking. To elucidate the structural basis for this difference in the inhibitor efficiency, we determined the crystal structure of a GII.4 protease. The structure revealed significant changes in the S2 substrate-binding pocket, making it noticeably smaller, and in the active site, with the catalytic triad residues showing conformational changes. Furthermore, a conserved arginine is found inserted into the active site, interacting with the catalytic histidine and restricting substrate/inhibitor access to the S2 pocket. This interaction alters the relationships between the catalytic residues and may allow for a pH-dependent regulation of protease activity. The changes we observed in the GII.4 protease structure may explain the reduced potency of the GI-specific inhibitors against the GII protease and therefore must be taken into account when designing broadly cross-reactive antivirals against NoVs.IMPORTANCE Human noroviruses (NoVs) cause sporadic and epidemic gastroenteritis worldwide. They are divided into seven genogroups (GI to GVII), with each genogroup further divided into several genotypes. Human NoVs belonging to genogroup II and genotype 4 (GII.4) are the most prevalent. Currently, there are no vaccines or antiviral drugs available for NoV infection. The protease encoded by NoV is considered a valuable target because of its essential role in replication. NoV protease structures have only been determined for the GI genogroup. We show here that the structure of the GII.4 protease exhibits several significant changes from GI proteases, including a unique pairing of an arginine with the catalytic histidine that makes the proteolytic activity of GII.4 protease pH sensitive. A comparative analysis of NoV protease structures may provide a rational framework for structure-based drug design of broadly cross-reactive inhibitors targeting NoVs.
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Arginina/metabolismo , Dominio Catalítico/genética , Histidina/metabolismo , Norovirus/metabolismo , Péptido Hidrolasas/metabolismo , Secuencia de Aminoácidos , Infecciones por Caliciviridae/metabolismo , Dominio Catalítico/fisiología , Variación Genética/genética , Genotipo , Humanos , Concentración de Iones de Hidrógeno , Norovirus/genética , Filogenia , ProteolisisRESUMEN
The somatic co-evolution of tumors and the cellular immune responses that combat them drives the diversity of immune-tumor interactions. This includes tumor mutations that generate neo-antigenic epitopes that elicit cytotoxic T-cell activity and subsequent pressure to select for genetic loss of antigen presentation. Most studies have focused on how tumor missense mutations can drive tumor immunity, but frameshift mutations have the potential to create far greater antigenic diversity. However, expression of this antigenic diversity is potentially regulated by Nonsense Mediated Decay (NMD) and NMD has been shown to be of variable efficiency in cancers. Here we studied how mutational changes influence global NMD and cytolytic immune responses. Using TCGA datasets, we derived novel patient-level metrics of 'NMD burden' and interrogated how different mutation and most importantly NMD burdens influence cytolytic activity using machine learning models and survival outcomes. We find that NMD is a significant and independent predictor of immune cytolytic activity. Different indications exhibited varying dependence on NMD and mutation burden features. We also observed significant co-alteration of genes in the NMD pathway, with a global increase in NMD efficiency in patients with NMD co-alterations. Finally, NMD burden also stratified patient survival in multivariate regression models in subset of cancer types. Our work suggests that beyond selecting for mutations that elicit NMD in tumor suppressors, tumor evolution may react to the selective pressure generated by inflammation to globally enhance NMD through coordinated amplification and/or mutation.
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Citotoxicidad Inmunológica/genética , Neoplasias/genética , Degradación de ARNm Mediada por Codón sin Sentido/fisiología , Evolución Biológica , Simulación por Computador , Citosol/metabolismo , Bases de Datos Genéticas , Evolución Molecular , Mutación del Sistema de Lectura/genética , Humanos , Aprendizaje Automático , Mutación/genética , Mutación Missense/genéticaRESUMEN
The identification of biologically significant variants in cancer genomes is critical to therapeutic discovery, but it is limited by the statistical power needed to discern driver from passenger. Independent biological data can be used to filter cancer exomes and increase statistical power. Large genetic databases for inherited diseases are uniquely suited to this task because they contain specific amino acid alterations with known pathogenicity and molecular mechanisms. However, no rigorous method to overlay this information onto the cancer exome exists. Here, we present a computational methodology that overlays any variant database onto the somatic mutations in all cancer exomes. We validate the computation experimentally and identify novel associations in a re-analysis of 7362 cancer exomes. This analysis identified activating SOS1 mutations associated with Noonan syndrome as significantly altered in melanoma and the first kinase-activating mutations in ACVR1 associated with adult tumors. Beyond a filter, significant variants found in both rare cancers and rare inherited diseases increase the unmet medical need for therapeutics that target these variants and may bootstrap drug discovery efforts in orphan indications.
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Receptores de Activinas Tipo I/genética , Colágeno Tipo III/genética , Biología Computacional/métodos , Bases de Datos Genéticas , Neoplasias Endometriales/genética , Predisposición Genética a la Enfermedad , Neoplasias Pulmonares/genética , Melanoma/genética , Síndrome de Noonan/genética , Proteína SOS1/genética , Secuencia de Aminoácidos , Línea Celular , Exoma/genética , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Femenino , Variación Genética/genética , Células HEK293 , Humanos , Mutación/genética , FosforilaciónRESUMEN
The substantial spatial and temporal heterogeneity observed in patient tumors poses considerable challenges for the design of effective drug combinations with predictable outcomes. Currently, the implications of tissue heterogeneity and sampling bias during diagnosis are unclear for selection and subsequent performance of potential combination therapies. Here, we apply a multiobjective computational optimization approach integrated with empirical information on efficacy and toxicity for individual drugs with respect to a spectrum of genetic perturbations, enabling derivation of optimal drug combinations for heterogeneous tumors comprising distributions of subpopulations possessing these perturbations. Analysis across probabilistic samplings from the spectrum of various possible distributions reveals that the most beneficial (considering both efficacy and toxicity) set of drugs changes as the complexity of genetic heterogeneity increases. Importantly, a significant likelihood arises that a drug selected as the most beneficial single agent with respect to the predominant subpopulation in fact does not reside within the most broadly useful drug combinations for heterogeneous tumors. The underlying explanation appears to be that heterogeneity essentially homogenizes the benefit of drug combinations, reducing the special advantage of a particular drug on a specific subpopulation. Thus, this study underscores the importance of considering heterogeneity in choosing drug combinations and offers a principled approach toward designing the most likely beneficial set, even if the subpopulation distribution is not precisely known.
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Antineoplásicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Heterogeneidad Genética , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Animales , Antineoplásicos/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Humanos , Ratones , Modelos Biológicos , Método de Montecarlo , Resultado del TratamientoRESUMEN
The integrative Vaccine Investigation and Online Information Network (VIOLIN) vaccine research database and analysis system (http://www.violinet.org) curates, stores, analyses and integrates various vaccine-associated research data. Since its first publication in NAR in 2008, significant updates have been made. Starting from 211 vaccines annotated at the end of 2007, VIOLIN now includes over 3240 vaccines for 192 infectious diseases and eight noninfectious diseases (e.g. cancers and allergies). Under the umbrella of VIOLIN, >10 relatively independent programs are developed. For example, Protegen stores over 800 protective antigens experimentally proven valid for vaccine development. VirmugenDB annotated over 200 'virmugens', a term coined by us to represent those virulence factor genes that can be mutated to generate successful live attenuated vaccines. Specific patterns were identified from the genes collected in Protegen and VirmugenDB. VIOLIN also includes Vaxign, the first web-based vaccine candidate prediction program based on reverse vaccinology. VIOLIN collects and analyzes different vaccine components including vaccine adjuvants (Vaxjo) and DNA vaccine plasmids (DNAVaxDB). VIOLIN includes licensed human vaccines (Huvax) and veterinary vaccines (Vevax). The Vaccine Ontology is applied to standardize and integrate various data in VIOLIN. VIOLIN also hosts the Ontology of Vaccine Adverse Events (OVAE) that logically represents adverse events associated with licensed human vaccines.
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Bases de Datos Genéticas , Vacunas/inmunología , Adyuvantes Inmunológicos , Antígenos/química , Antígenos/genética , Minería de Datos , Genes , Genómica , Humanos , Internet , Plásmidos/genética , Proteínas/inmunología , Alineación de Secuencia , Programas Informáticos , Integración de Sistemas , Vacunas/efectos adversos , Vacunas/química , Vacunas/genética , Vacunas Atenuadas/genética , Vacunas de ADN/genética , Factores de Virulencia/genética , Factores de Virulencia/inmunologíaRESUMEN
Heparan sulfate (HS) is degraded in lysosome by a series of glycosidases. Before the glycosidases can act, the terminal glucosamine of HS must be acetylated by the integral lysosomal membrane enzyme heparan-α-glucosaminide N-acetyltransferase (HGSNAT). Mutations of HGSNAT cause HS accumulation and consequently mucopolysaccharidosis IIIC, a devastating lysosomal storage disease characterized by progressive neurological deterioration and early death where no treatment is available. HGSNAT catalyzes a unique transmembrane acetylation reaction where the acetyl group of cytosolic acetyl-CoA is transported across the lysosomal membrane and attached to HS in one reaction. However, the reaction mechanism remains elusive. Here we report six cryo-EM structures of HGSNAT along the reaction pathway. These structures reveal a dimer arrangement and a unique structural fold, which enables the elucidation of the reaction mechanism. We find that a central pore within each monomer traverses the membrane and controls access of cytosolic acetyl-CoA to the active site at its luminal mouth where glucosamine binds. A histidine-aspartic acid catalytic dyad catalyzes the transfer reaction via a ternary complex mechanism. Furthermore, the structures allow the mapping of disease-causing variants and reveal their potential impact on the function, thus creating a framework to guide structure-based drug discovery efforts.
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Acetiltransferasas , Microscopía por Crioelectrón , Lisosomas , Mucopolisacaridosis III , Mucopolisacaridosis III/genética , Mucopolisacaridosis III/metabolismo , Mucopolisacaridosis III/enzimología , Humanos , Lisosomas/metabolismo , Lisosomas/enzimología , Acetiltransferasas/metabolismo , Acetiltransferasas/química , Acetiltransferasas/genética , Dominio Catalítico , Mutación , Heparitina Sulfato/metabolismo , Acetilcoenzima A/metabolismo , Acetilcoenzima A/química , Modelos Moleculares , Glucosamina/metabolismo , Glucosamina/química , Acetilación , Membranas Intracelulares/metabolismoRESUMEN
The mammalian orthoreovirus (reovirus) σNS protein is required for formation of replication compartments that support viral genome replication and capsid assembly. Despite its functional importance, a mechanistic understanding of σNS is lacking. We conducted structural and biochemical analyses of a σNS mutant that forms dimers instead of the higher-order oligomers formed by wildtype (WT) σNS. The crystal structure shows that dimers interact with each other using N-terminal arms to form a helical assembly resembling WT σNS filaments in complex with RNA observed using cryo-EM. The interior of the helical assembly is of appropriate diameter to bind RNA. The helical assembly is disrupted by bile acids, which bind to the same site as the N-terminal arm. This finding suggests that the N-terminal arm functions in conferring context-dependent oligomeric states of σNS, which is supported by the structure of σNS lacking an N-terminal arm. We further observed that σNS has RNA chaperone activity likely essential for presenting mRNA to the viral polymerase for genome replication. This activity is reduced by bile acids and abolished by N-terminal arm deletion, suggesting that the activity requires formation of σNS oligomers. Our studies provide structural and mechanistic insights into the function of σNS in reovirus replication.
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Orthoreovirus , Reoviridae , Animales , Orthoreovirus/genética , Replicación Viral , Reoviridae/genética , ARN/metabolismo , Ácidos y Sales Biliares , ARN Viral/genética , Mamíferos/genéticaRESUMEN
It is shown that structural disorder-in the form of anisotropic, picoscale atomic displacements-modulates the refractive index tensor and results in the giant optical anisotropy observed in BaTiS3, a quasi-1D hexagonal chalcogenide. Single-crystal X-ray diffraction studies reveal the presence of antipolar displacements of Ti atoms within adjacent TiS6 chains along the c-axis, and threefold degenerate Ti displacements in the a-b plane. 47/49Ti solid-state NMR provides additional evidence for those Ti displacements in the form of a three-horned NMR lineshape resulting from a low symmetry local environment around Ti atoms. Scanning transmission electron microscopy is used to directly observe the globally disordered Ti a-b plane displacements and find them to be ordered locally over a few unit cells. First-principles calculations show that the Ti a-b plane displacements selectively reduce the refractive index along the ab-plane, while having minimal impact on the refractive index along the chain direction, thus resulting in a giant enhancement in the optical anisotropy. By showing a strong connection between structural disorder with picoscale displacements and the optical response in BaTiS3, this study opens a pathway for designing optical materials with high refractive index and functionalities such as large optical anisotropy and nonlinearity.
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The lasting threat of viral pandemics necessitates the development of tailorable first-response antivirals with specific but adaptive architectures for treatment of novel viral infections. Here, such an antiviral platform has been developed based on a mixture of hetero-peptides self-assembled into functionalized ß-sheets capable of specific multivalent binding to viral protein complexes. One domain of each hetero-peptide is designed to specifically bind to certain viral proteins, while another domain self-assembles into fibrils with epitope binding characteristics determined by the types of peptides and their molar fractions. The self-assembled fibrils maintain enhanced binding to viral protein complexes and retain high resilience to viral mutations. This method is experimentally and computationally tested using short peptides that specifically bind to Spike proteins of SARS-CoV-2. This platform is efficacious, inexpensive, and stable with excellent tolerability.
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COVID-19 , Humanos , Péptidos/química , SARS-CoV-2/metabolismo , Antivirales/farmacología , Proteínas Virales , Glicoproteína de la Espiga del Coronavirus/metabolismoRESUMEN
Objective.Human activity recognition (HAR) has become increasingly important in healthcare, sports, and fitness domains due to its wide range of applications. However, existing deep learning based HAR methods often overlook the challenges posed by the diversity of human activities and data quality, which can make feature extraction difficult. To address these issues, we propose a new neural network model called MAG-Res2Net, which incorporates the Borderline-SMOTE data upsampling algorithm, a loss function combination algorithm based on metric learning, and the Lion optimization algorithm.Approach.We evaluated the proposed method on two commonly utilized public datasets, UCI-HAR and WISDM, and leveraged the CSL-SHARE multimodal human activity recognition dataset for comparison with state-of-the-art models.Main results.On the UCI-HAR dataset, our model achieved accuracy, F1-macro, and F1-weighted scores of 94.44%, 94.38%, and 94.26%, respectively. On the WISDM dataset, the corresponding scores were 98.32%, 97.26%, and 98.42%, respectively.Significance.The proposed MAG-Res2Net model demonstrates robust multimodal performance, with each module successfully enhancing model capabilities. Additionally, our model surpasses current human activity recognition neural networks on both evaluation metrics and training efficiency. Source code of this work is available at:https://github.com/LHY1007/MAG-Res2Net.