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Understanding how biophysical and biochemical microenvironmental cues together influence the regenerative activities of muscle stem cells and their progeny is crucial in strategizing remedies for pathological dysregulation of these cues in aging and disease. In this study, we investigated the cell-level influences of extracellular matrix (ECM) ligands and culture substrate stiffness on primary human myoblast contractility and proliferation within 16â h of plating and found that tethered fibronectin led to stronger stiffness-dependent responses compared to laminin and collagen. A proteome-wide analysis further uncovered cell metabolism, cytoskeletal and nuclear component regulation distinctions between cells cultured on soft and stiff substrates. Interestingly, we found that softer substrates increased the incidence of myoblasts with a wrinkled nucleus, and that the extent of wrinkling could predict Ki67 (also known as MKI67) expression. Nuclear wrinkling and Ki67 expression could be controlled by pharmacological manipulation of cellular contractility, offering a potential cellular mechanism. These results provide new insights into the regulation of human myoblast stiffness-dependent contractility response by ECM ligands and highlight a link between myoblast contractility and proliferation.
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Matriz Extracelular , Membrana Nuclear , Humanos , Antígeno Ki-67/metabolismo , Matriz Extracelular/metabolismo , Mioblastos/metabolismo , Proliferación CelularRESUMEN
Accurate chromosome segregation, monitored by the spindle assembly checkpoint (SAC), is crucial for the production of euploid cells. Previous in vitro studies by us and others showed that Mad2, a core member of the SAC, performs a checkpoint function in oocyte meiosis. Here, through an oocyte-specific knockout approach in mouse, we reconfirmed that Mad2-deficient oocytes exhibit an accelerated metaphase-to-anaphase transition caused by premature degradation of securin and cyclin B1 and subsequent activation of separase in meiosis I. However, it was surprising that the knockout mice were completely fertile and the resulting oocytes were euploid. In the absence of Mad2, other SAC proteins, including BubR1, Bub3 and Mad1, were normally recruited to the kinetochores, which likely explains the balanced chromosome separation. Further studies showed that the chromosome separation in Mad2-null oocytes was particularly sensitive to environmental changes and, when matured in vitro, showed chromosome misalignment, lagging chromosomes, and aneuploidy with premature separation of sister chromatids, which was exacerbated at a lower temperature. We reveal for the first time that Mad2 is dispensable for proper chromosome segregation but acts to mitigate environmental stress in meiotic oocytes.
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Proteínas de Ciclo Celular , Huso Acromático , Animales , Ratones , Proteínas de Ciclo Celular/metabolismo , Huso Acromático/metabolismo , Proteínas Mad2/genética , Proteínas Mad2/metabolismo , Segregación Cromosómica/genética , Oocitos/metabolismo , Cinetocoros/metabolismo , Meiosis/genéticaRESUMEN
Oocyte meiotic maturation failure and chromosome abnormality is one of the main causes of infertility, abortion, and diseases. The mono-orientation of sister chromatids during the first meiosis is important for ensuring accurate chromosome segregation in oocytes. MEIKIN is a germ cell-specific protein that can regulate the mono-orientation of sister chromatids and the protection of the centromeric cohesin complex during meiosis I. Here we found that MEIKIN is a maternal protein that was highly expressed in mouse oocytes before the metaphase I (MI) stage, but became degraded by the MII stage and dramatically reduced after fertilization. Strikingly, MEIKIN underwent phosphorylation modification after germinal vesicle breakdown (GVBD), indicating its possible function in subsequent cellular event regulation. We further showed that MEIKIN phosphorylation was mediated by PLK1 at its carboxyl terminal region and its C-terminus was its key functional domain. To clarify the biological significance of meikin degradation during later stages of oocyte maturation, exogenous expression of MEIKIN was employed, which showed that suppression of MEIKIN degradation resulted in chromosome misalignment, cyclin B1 and Securin degradation failure, and MI arrest through a spindle assembly checkpoint (SAC)-independent mechanism. Exogenous expression of MEIKIN also inhibited metaphase II (MII) exit and early embryo development. These results indicate that proper MEIKIN expression level and its C-terminal phosphorylation by PLK1 are critical for regulating the metaphase-anaphase transition in meiotic oocyte. The findings of this study are important for understanding the regulation of chromosome segregation and the prevention meiotic abnormality.
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OBJECTIVE: Cystic echinococcosis (CE) represents a profoundly perilous zoonotic disease. The advent of viral macrogenomics has facilitated the exploration of hitherto uncharted viral territories. In the scope of this investigation, our objective is to scrutinize disparities in the intestinal microbiotic ecosystems of canines dwelling in elevated terrains and those afflicted by Echinococcus infection, employing the tool of viral macrogenomics. METHODS: In this study, we collected a comprehensive total of 1,970 fecal samples from plateau dogs infected with Echinococcus, as well as healthy control plateau dogs from the Yushu and Guoluo regions in the highland terrain of China. These samples were subjected to viral macrogenomic analysis to investigate the viral community inhabiting the canine gastrointestinal tract. RESULTS: Our meticulous analysis led to the identification of 136 viral genomic sequences, encompassing eight distinct viral families. CONCLUSION: The outcomes of this study hold the potential to enhance our comprehension of the intricate interplay between hosts, parasites, and viral communities within the highland canine gut ecosystem. Through the examination of phage presence, it may aid in early detection or assessment of infection severity, providing valuable insights into Echinococcus infection and offering prospects for potential treatment strategies.
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Enfermedades de los Perros , Equinococosis , Echinococcus , Heces , Microbioma Gastrointestinal , Animales , Perros , Equinococosis/veterinaria , Enfermedades de los Perros/parasitología , Enfermedades de los Perros/microbiología , Enfermedades de los Perros/virología , China , Heces/parasitología , Heces/microbiología , Heces/virología , Echinococcus/genética , Echinococcus/aislamiento & purificación , Genoma Viral , Virus/clasificación , Virus/aislamiento & purificación , Virus/genéticaRESUMEN
Tunable phonon transport properties of two-dimensional materials are desirable for effective heat management in various application scenarios. Here, we demonstrate by first-principles calculations and Boltzmann transport theory that the lattice thermal conductivity of siligene could be efficiently engineered by forming various stacking configurations. Unlike few-layer graphene, the stacked siligenes are found to be covalently bonded along the out-of-plane direction, which leads to unique dependence of the thermal conductivity on both the stacking order and layer number. Due to the restricted flexural phonon scattering induced by the horizontal reflection symmetry, the AA stacking configuration of bilayer siligene exhibits obviously higher thermal conductivity compared with the AB stacking. In addition, we observe increasing thermal conductivity with the layer number, as evidenced by the reduced phonon scattering phase space and Grüneisen parameter. Interestingly, the Fuchs-Sondheimer model works well for the thickness-dependent thermal conductivity of stacked siligenes.
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Developing multitargeted ligands as promising therapeutics for Alzheimer's disease (AD) has been considered important. Herein, a novel class of cinnamamide/ester-triazole hybrids with multifaceted effects on AD was developed based on the multitarget-directed ligands strategy. Thirty-seven cinnamamide/ester-triazole hybrids were synthesized, with most exhibiting significant inhibitory activity against Aß-induced toxicity at a single concentration in vitro. The most optimal hybrid compound 4j inhibited copper-induced Aß toxicity in AD cells. its action was superior to that of donepezil and memantine. It also moderately inhibited intracellular AChE activity and presented favorable bioavailability and blood-brain barrier penetration with low toxicity in vivo. Of note, it ameliorated cognitive impairment, neuronal degeneration, and Aß deposition in Aß1-42-injured mice. Mechanistically, the compound regulated APP processing by promoting the ADAM10-associated nonamyloidogenic signaling and inhibiting the BACE1-mediated amyloidogenic pathway. Moreover, it suppressed intracellular AChE activity and tau phosphorylation. Therefore, compound 4j may be a promising multitargeted active molecule against AD.
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Enfermedad de Alzheimer , Péptidos beta-Amiloides , Cinamatos , Triazoles , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Animales , Triazoles/química , Triazoles/farmacología , Triazoles/síntesis química , Cinamatos/química , Cinamatos/farmacología , Cinamatos/síntesis química , Humanos , Ratones , Péptidos beta-Amiloides/metabolismo , Péptidos beta-Amiloides/antagonistas & inhibidores , Relación Estructura-Actividad , Estructura Molecular , Ésteres/química , Ésteres/farmacología , Ésteres/síntesis química , Relación Dosis-Respuesta a Droga , Acetilcolinesterasa/metabolismo , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/síntesis química , Descubrimiento de Drogas , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/síntesis química , Fragmentos de Péptidos/metabolismo , Fragmentos de Péptidos/antagonistas & inhibidores , MasculinoRESUMEN
PURPOSE: The optimal treatment strategy for oropharyngeal cancer (OPC) is undetermined. We aim to compare the survival outcomes of OPC patients treated with upfront surgery versus definitive radiotherapy (RT). METHODS: A total of 8057 cases were retrieved from the Surveillance, Epidemiology, and End Results database. Primary endpoints were cancer-specific and noncancer mortalities, which were estimated using cumulative incidence function and compared by Gray's test. Univariate and multivariate Fine-Gray subdistribution hazard models were used to estimate the effects of treatment modality on mortality. Subgroup analyses were performed in propensity-score-matched cohorts. All the analyses were conducted separately in human papillomavirus (HPV)-negative and HPV-positive cohorts. RESULTS: In the HPV-negative cohort, definitive RT was independently associated with increased risk of cancer-specific mortality (adjusted subdistribution hazard ratio [SHR], 1.31; 95% confidence interval [CI], 1.05-1.64; P = 0.017) and noncancer mortality (adjusted SHR, 1.59; 95% CI 1.13-2.25; P = 0.008). In the HPV-positive cohort, definitive RT was independently associated with increased risk of cancer-specific mortality (adjusted SHR, 1.51; 95% CI 1.23-1.85; P < 0.001) and noncancer mortality (adjusted SHR, 1.53; 95% CI 1.11-2.12; P = 0.009). CONCLUSION: Upfront surgery is a superior treatment modality compared with definitive RT in terms of lowering cancer-specific and noncancer mortality in OPC patients, regardless of HPV status. Further prospective clinical trials are needed to confirm our findings.
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Neoplasias Orofaríngeas , Programa de VERF , Humanos , Neoplasias Orofaríngeas/radioterapia , Neoplasias Orofaríngeas/mortalidad , Neoplasias Orofaríngeas/cirugía , Neoplasias Orofaríngeas/virología , Masculino , Femenino , Persona de Mediana Edad , Anciano , Medición de Riesgo , Infecciones por Papillomavirus/radioterapia , Infecciones por Papillomavirus/complicaciones , Infecciones por Papillomavirus/mortalidad , Puntaje de Propensión , Estudios Retrospectivos , Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/cirugíaRESUMEN
BACKGROUND: RNA splicing plays significant roles in fundamental biological activities. However, our knowledge about the roles of alternative splicing and underlying mechanisms during spermatogenesis is limited. RESULTS: Here, we report that Serine/arginine-rich splicing factor 2 (SRSF2), also known as SC35, plays critical roles in alternative splicing and male reproduction. Male germ cell-specific deletion of Srsf2 by Stra8-Cre caused complete infertility and defective spermatogenesis. Further analyses revealed that deletion of Srsf2 disrupted differentiation and meiosis initiation of spermatogonia. Mechanistically, by combining RNA-seq data with LACE-seq data, we showed that SRSF2 regulatory networks play critical roles in several major events including reproductive development, spermatogenesis, meiotic cell cycle, synapse organization, DNA recombination, chromosome segregation, and male sex differentiation. Furthermore, SRSF2 affected expression and alternative splicing of Stra8, Stag3 and Atr encoding critical factors for spermatogenesis in a direct manner. CONCLUSIONS: Taken together, our results demonstrate that SRSF2 has important functions in spermatogenesis and male fertility by regulating alternative splicing.
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Empalme del ARN , Espermatogénesis , Masculino , Humanos , Espermatogénesis/genética , Proteínas de Unión al ARN/genética , Empalme Alternativo , Meiosis/genética , ARN MensajeroRESUMEN
PURPOSE: Hirschsprung's disease (HSCR) is the leading cause of neonatal functional intestinal obstruction, which has been identified in many familial cases. HSCR, a multifactorial disorder of enteric nervous system (ENS) development, is associated with at least 24 genes and seven chromosomal loci, with RET and EDNRB as its major genes. We present a genetic investigation of familial HSCR to clarify the genotype-phenotype relationship. METHODS: We performed whole exome sequencing (WES) on Illumina HiSeq X Ten platform to investigate genetic backgrounds of core family members, and identified the possibly harmful mutation genes. Mutation carriers and pedigree relatives were validated by Sanger sequencing for evaluating the gene penetrance. RESULTS: Four familial cases showed potential disease-relative variants in EDNRB and RET gene, accounting for all detection rate of 57.1%. Three familial cases exhibited strong pathogenic variants as frameshift or missense mutations in EDNRB gene. A novel c.367delinsTT mutation of EDNRB was identified in one family member. The other two EDNRB mutations, c.553G>A in family 2 and c.877delinsTT in family 5, have been reported in previous literatures. The penetrance of EDNRB variants was 33-50% according mutation carries. In family 6, the RET c.1858T>C (C620R) point mutation has previously been reported to cause HSCR, with 28.5% penetrance. CONCLUSION: We identified a novel EDNRB (deleted C and inserted TT) mutation in this study using WES. Heterozygote variations in EDNRB gene were significantly enriched in three families and RET mutations were identified in one family. EDNRB variants showed an overall higher incidence and penetrance than RET in southern Chinese families cases.
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Enfermedad de Hirschsprung , Obstrucción Intestinal , Receptor de Endotelina B , Humanos , Recién Nacido , China/epidemiología , Enfermedad de Hirschsprung/genética , Incidencia , Mutación , Receptor de Endotelina B/genéticaRESUMEN
During the oocyte growth, maturation and zygote development, chromatin structure keeps changing to regulate different nuclear activities. Here, we reported the role of SMC2, a core component of condensin complex, in oocyte and embryo development. Oocyte-specific conditional knockout of SMC2 caused female infertility. In the absence of SMC2, oocyte meiotic maturation and ovulation occurred normally, but chromosome condensation showed defects and DNA damages were accumulated in oocytes. The pronuclei were abnormally organized and micronuclei were frequently observed in fertilized eggs, their activity was impaired, and embryo development was arrested at the one-cell stage, suggesting that maternal SMC2 is essential for embryonic development.
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Núcleo Celular , Cromosomas , Animales , Femenino , Ratones , Embarazo , Ciclo Celular , Núcleo Celular/fisiología , Desarrollo Embrionario/genética , Meiosis/genética , Oocitos/fisiología , CigotoRESUMEN
BACKGROUND: Inflammation of the fetal membranes is an indispensable event of labor onset at both term and preterm birth. Interleukin-33 (IL-33) is known to participate in inflammation via ST2 (suppression of tumorigenicity 2) receptor as an inflammatory cytokine. However, it remains unknown whether IL-33/ST2 axis exists in human fetal membranes to promote inflammatory reactions in parturition. METHODS: The presence of IL-33 and ST2 and their changes at parturition were examined with transcriptomic sequencing, quantitative real-time polymerase chain reaction, Western blotting or immunohistochemistry in human amnion obtained from term and preterm birth with or without labor. Cultured primary human amnion fibroblasts were utilized to investigate the regulation and the role of IL-33/ST2 axis in the inflammation reactions. A mouse model was used to further study the role of IL-33 in parturition. RESULTS: Although IL-33 and ST2 expression were detected in both epithelial and fibroblast cells of human amnion, they are more abundant in amnion fibroblasts. Their abundance increased significantly in the amnion at both term and preterm birth with labor. Lipopolysaccharide, serum amyloid A1 and IL-1ß, the inflammatory mediators pertinent to labor onset, could all induce IL-33 expression through NF-κB activation in human amnion fibroblasts. In turn, via ST2 receptor, IL-33 induced the production of IL-1ß, IL-6 and PGE2 in human amnion fibroblasts via the MAPKs-NF-κB pathway. Moreover, IL-33 administration induced preterm birth in mice. CONCLUSION: IL-33/ST2 axis is present in human amnion fibroblasts, which is activated in both term and preterm labor. Activation of this axis leads to increased production of inflammatory factors pertinent to parturition, and results in preterm birth. Targeting the IL-33/ST2 axis may have potential value in the treatment of preterm birth.
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Amnios , Nacimiento Prematuro , Animales , Femenino , Humanos , Recién Nacido , Ratones , Embarazo , Amnios/metabolismo , Fibroblastos/metabolismo , Inflamación/metabolismo , Proteína 1 Similar al Receptor de Interleucina-1/genética , Interleucina-33 , FN-kappa B/metabolismo , Parto/metabolismo , Nacimiento Prematuro/metabolismoRESUMEN
Atomic heating on single atoms (SAs) to maximize the catalytic efficiency of each active site would be a fascinating solution to break the bottleneck for the performance improvement of single-atom catalysts (SACs) but highly challenging task. Here, based on the Gd@MoS2 SACs synthesized by a facile laser molecular beam epitaxy method, high-frequency alternating magnetic field (AMF) technology is employed to induce atomic magnetic heating on Gd SAs that is meanwhile demonstrated to be the catalytic active center. Significant improvement in catalytic kinetics under AMF excitation (3.9 mT) is achieved, yielding a remarkable enhancement of hydrogen evolution reaction magnetothermal-current by ≈924%. Through theoretical calculations and spin-related electrochemical experiments, such promotion in catalyst activity can be attributed to spin flip (or canting) in Gd SAs leading to the atomic magnetic heating effect on catalytic active center. Together with the embodied high stability, the implement of AMF to the SAs field is demonstrated in this work, and the precisely atomic magnetic heating on specific SAs offers unprecedented thinking for further improvement of SACs performance in the future.
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Although (oxy)hydroxides generated by electrochemical reconstruction (EC-reconstruction) of transition-metal catalysts exhibit highly catalytic activities, the amorphous nature fundamentally impedes the electrochemical kinetics due to its poor electrical conductivity. Here, EC-reconstructed NiFe/NiFeOOH core/shell nanoparticles in highly conductive carbon matrix based on the pulsed laser deposition prepared NiFe nanoparticles is successfully confined. Electrochemical characterizations and first-principles calculations demonstrate that the reconstructed NiFe/NiFeOOH core/shell nanoparticles exhibit high oxygen evolution reaction (OER) electrocatalytic activity (a low overpotential of 342.2 mV for 10 mA cm-2 ) and remarkable durability due to the efficient charge transfer in the highly conductive confined heterostructure. More importantly, benefit from the superparamagnetic nature of the reconstructed NiFe/NiFeOOH core/shell nanoparticles, a large OER improvement is achieved (an ultralow overpotential of 209.2 mV for 10 mA cm-2 ) with an alternating magnetic field stimulation. Such OER improvement can be attributed to the Néel relaxation related magnetic heating effect functionalized superparamagnetic NiFe cores, which are generally underutilized in reconstructed core/shell nanoparticles. This work demonstrates that the designed superparamagnetic core/shell nanoparticles, combined with the large improvement by magnetic heating effect, are expected to be highly efficient OER catalysts along with the confined structure guaranteed high conductivity and catalytic stability.
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As the most abundant organelles in oocytes, mitochondria play an important role in maintaining oocyte quality. Here, we report that March5, encoding a mitochondrial ubiquitin ligase that promotes mitochondrial elongation, plays a critical role in mouse oocyte meiotic maturation via regulating mitochondrial function. The subcellular localization of MARCH5 was similar to the mitochondrial distribution during mouse oocyte meiotic progression. Knockdown of March5 caused decreased ratios of the first polar body extrusion. March5-siRNA injection resulted in oocyte mitochondrial dysfunctions, manifested by increased reactive oxygen species, decreased ATP content as well as decreased mitochondrial membrane potential, leading to reduced ability of spindle formation and an increased ratio of kinetochore-microtubule detachment. Further study showed that the continuous activation of the spindle assembly checkpoint and the failure of Cyclin B1 degradation caused MI arrest and first polar body (PB1) extrusion failure in March5 knockdown oocytes. Taken together, our results demonstrated that March5 plays an essential role in mouse oocyte meiotic maturation, possibly via regulation of mitochondrial function and/or ubiquitination of microtubule dynamics- or cell cycle-regulating proteins.
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Oogénesis , Ubiquitina-Proteína Ligasas , Animales , Ratones , Mitocondrias/metabolismo , Oocitos/metabolismo , Proteínas/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Epilepsy is a common chronic neurological disorder characterized by widespread neuronal death. The purpose of this study was to investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) m6A methylation in epilepsy. To create epileptic models, the rats were given Lithium chloride and pilocarpine, and isolated primary rat hippocampal neurons were cultured in an Mg2+ -free medium. The frequency of seizures was recorded in the epilepsy group of rats. The functional tests included TUNEL, MTT, and flow cytometry. Mechanistically, RNA degradation assay, RNA immunoprecipitation, and methylated RNA immunoprecipitation were performed. In epileptic models, Nrf2 and fat mass and obesity-associated (FTO) levels were downregulated, whereas YT521-B homology (YTH) domain family protein 2 (YTHDF2) was upregulated. Additionally, in epileptic models, there was a rise in the m6A methylation level of Nrf2 mRNA. Overexpressing FTO increased cell viability and reduced apoptosis, but Nrf2 interference reversed these effects. Meanwhile, FTO overexpression decreased the m6A methylation of Nrf2 mRNA. Moreover, YTHDF2 bound to Nrf2 mRNA and decreased its stability. Furthermore, FTO overexpression reduced seizure frequency in rats and inhibited hippocampal neuron apoptosis via lowering the m6A methylation level of Nrf2 mRNA. Overexpressing FTO reduced m6A methylation of Nrf2 mRNA, increased cell viability, suppressed apoptosis, and slowed the progression of epileptic diseases, which is linked to YTHDF2 binding to m6A-modified Nrf2 and promoting its degradation, as well as downregulating Nrf2 expression in hippocampal neurons.
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Epilepsia , Factor 2 Relacionado con NF-E2 , Ratas , Animales , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Regulación hacia Abajo , Epilepsia/metabolismo , ARN/efectos adversos , ARN/metabolismo , ARN Mensajero/metabolismo , Convulsiones/metabolismo , Neuronas/metabolismo , Hipocampo/metabolismoRESUMEN
OBJECTIVES: Sterile inflammation of fetal membranes is an indispensable event of normal parturition. However, triggers of sterile inflammation are not fully resolved. Serum amyloid A1 (SAA1) is an acute phase protein produced primarily by the liver. Fetal membranes can also synthesize SAA1 but its functions are not well defined. Given the role of SAA1 in the acute phase response to inflammation, we postulated that SAA1 synthesized in the fetal membranes may be a trigger of local inflammation at parturition. METHODS: The changes of SAA1 abundance in parturition were studied in the amnion of human fetal membranes. The role of SAA1 in chemokine expression and leukocyte chemotaxis was examined in cultured human amnion tissue explants as well as primary human amnion fibroblasts. The effects of SAA1 on monocytes, macrophages and dendritic cells were investigated in cells derived from a human leukemia monocytic cell line (THP-1). RESULTS: SAA1 synthesis increased significantly in human amnion at parturition. SAA1 evoked multiple chemotaxis pathways in human amnion fibroblasts along with upregulation of a series of chemokines via both toll-like receptor 4 (TLR4) and formyl peptide receptor 2 (FPR2). Moreover, SAA1-conditioned medium of cultured amnion fibroblasts was capable of chemoattracting virtually all types of mononuclear leukocytes, particularly monocytes and dendritic cells, which reconciled with the chemotactic activity of conditioned medium of cultured amnion tissue explants collected from spontaneous labor. Furthermore, SAA1 could induce the expression of genes associated with inflammation and extracellular matrix remodeling in monocytes, macrophages and dendritic cells derived from THP-1. CONCLUSIONS: SAA1 is a trigger of sterile inflammation of the fetal membranes at parturition.
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Amnios , Parto , Embarazo , Femenino , Humanos , Amnios/metabolismo , Medios de Cultivo Condicionados/metabolismo , Medios de Cultivo Condicionados/farmacología , Parto/genética , Parto/metabolismo , Membranas Extraembrionarias/metabolismo , Quimiocinas/metabolismo , Inflamación/metabolismo , Proteína Amiloide A SéricaRESUMEN
Two-dimensional (2D) layered palladium dichalcogenides PdX2 (X = S and Se) have attracted increasing interest due to their tunable electronic structure and abundant physicochemical properties. Recently, as the sister material of PdX2, PdSSe has received increasing attention and shows great promise for technological applications and fundamental research. In the present study, we focus on the layer-dependent geometry, electronic structure, and optical properties of PdSSe using first-principles calculations. The lattice shrinkage effect present in the 2D structure is suppressed with increasing number of layers. Attributed to the strong interlayer coupling interactions, the band gap decreases from 2.30 to 0.83 eV with increased thickness. Particularly, the dispersion of the band edges on the high symmetry path changes considerably from the monolayer to bilayer PdSSe, resulting in shifts of the conduction band minimum and valence band maximum. The multilayer PdSSe shows band convergence feature with multi-valley for the conduction band, which are maintained with reduced effective mass. Furthermore, the increasing number of layers drives a wider absorption range in the visible light region, and the light absorption capability increases from â¼10% to â¼30%. Meanwhile, the band edge positions of the multilayer PdSSe are more appropriate for photocatalytic water splitting. Our theoretical study reveals the enhanced valley convergence, conductivity and optical absorption performance of the few-layer PdSSe, which suggests its promising application in thermoelectric conversion, solar harvesting and photocatalysis.
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Due to their unique structure, abundant properties and potential applications, low-dimensional materials with covalently bonded building blocks through van der Waals (vdW) interactions have sparked widespread interest. Recently, the bulk phase NbS4 consisting of one-dimensional (1D) chains has been synthesized successfully, adding a new member to the group V metallic polychalcogenide family. In the present study, based on density functional theory calculations, we obtained a better understanding of the stability, mechanical properties, electronic structures, transport properties and optical performances of the bulk phase NbS4. Furthermore, the possibility of exfoliating 1D single-chain nanowires from the bulk phase was uncovered. Both bulk phase and 1D nanowires show dynamic, thermal, and mechanical stabilities. The bulk phase possesses an indirect band gap of 1.39 eV with high anisotropic carrier mobilities of 471.814 cm2 s-1 v-1 for electrons (along the b axis direction) and 546.92 cm2 s-1 v-1 for holes (along the a axis direction). The single-chain nanowire exhibits remarkable flexibility and can resist 24% tensile strain along the chain direction. The decreased dimension from the bulk phase to the individual 1D chain not only makes the band gap increase to 1.81 eV but also results in an indirect-to-direct band gap transition, indicating a strong quantum confinement effect. The 1D single-chain nanowire also shows high carrier mobilities of 111.91 cm2 s-1 v-1 for electrons and 316.63 cm2 s-1 v-1 for holes along the chain direction. In addition, both bulk phase and 1D nanowire display excellent visible light absorption performance along the chain direction and the absorption coefficients reach the order of 106 and 105 cm-1. These promising properties render quasi 1D NbS4 as candidate materials for nanoscale applications in high-performance optoelectronic and nanoelectronic devices. The predicted unconventional properties of NbS4 not only provide a meaningful complement to the fascinating quasi 1D material family, but also will attract extensive interest from a wide audience to explore unanticipated properties and design new nanoscale devices based on NbS4.
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Microtubule plus-end tracking proteins (+TIPs) associate with growing microtubule plus ends and control microtubule dynamics and interactions with different cellular structures during cell division, cell migration and morphogenesis. Microtubule-associated RP/EB family member 2 (MAPRE2/EB2) is a highly conserved core component of +TIPs networks, but whether this molecule is required for mammalian meiotic progression is unknown. In this study, we investigated the expression and function of MAPRE2 during oocyte maturation. Our results showed that MAPRE2 was consistently expressed from germinal vesicle (GV) to metaphase II (MII) stages and that MAPRE2 was distributed in the cytoplasm of oocytes at GV stage and along the spindle at metaphase I (MI) and MII stages. Small interfering RNA-mediated knockdown of Mapre2 severely impaired microtubule stability, kinetochore-microtubule attachment, and chromosome alignment and subsequently caused spindle assembly checkpoint (SAC) activation and cyclin B1 nondegradation, leading to failure of chromosome segregation and first polar body extrusion. This study demonstrates for the first time that MAPRE2 plays an important role during mouse oocyte meiosis.
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Meiosis , Huso Acromático , Animales , Segregación Cromosómica , Mamíferos , Metafase , Ratones , Oocitos/metabolismo , Huso Acromático/metabolismoRESUMEN
Alternating magnetic field (AMF) is a promising methodology for further improving magnetic single-atom catalyst (SAC) activity toward oxygen evolution reaction (OER). Herein, the anchoring of Co single atoms on MoS2 support (Co@MoS2), leading to the appearance of in-plane room-temperature ferromagnetic properties, is favorable for the parallel spin arrangement of oxygen atoms when a magnetic field is applied. Moreover, field-assisted electrocatalytic experiments confirmed that the spin direction of Co@MoS2 is changing with the applied magnetic field. On this basis, under AMF, the active sites in ferromagnetic Co@MoS2 were heated by exploiting the magnetic heating generated from spin polarization flip of these SACs to further expedite OER efficiency, with overpotential at 10 mA cm-2 reduced from 317 mV to 250 mV. This work introduces a feasible and efficient approach to enhance the OER performance of Co@MoS2 by AMF, shedding some light on the further development of magnetic SACs for energy conversion.