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Apurinic/apyrimidinic (AP) sites are one of the most abundant DNA lesions and are mainly repaired by AP endonucleases (APEs). While most eukaryotic genomes encode two APEs, plants usually possess three APEs, namely APE1L, APE2, and ARP. To date, the biological relevance and functional divergence of plant APEs are unclear. Here, we show that the three plant APEs have ancient origins, with the APE1L clade being plant-specific. In Arabidopsis thaliana, simultaneously mutating APE1L and APE2, but not ARP alone or in combination with either APE1L or APE2, results in clear developmental defects linked to genotoxic stress. Genetic analyses indicated that the three plant APEs have different substrate preferences in vivo. ARP is mainly responsible for AP site repair, while APE1L and APE2 prefer to repair 3'-blocked single-stranded DNA breaks. We further determined that APEs play an important role in DNA repair and the maintenance of genomic integrity in meiotic cells. The ape1l ape2 double mutant exhibited a greatly enhanced frequency of sporulation 1 (SPO11-1)-dependent and SPO11-1-independent double-stranded DNA breaks. The DNA damage response (DDR) was activated in ape1l ape2 to trigger pollen abortion. Our findings suggest functional divergence of plant APEs and reveal important roles of plant APEs during vegetative and reproductive development.
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Proteínas de Arabidopsis , Arabidopsis , Hominidae , Animales , ADN-(Sitio Apurínico o Apirimidínico) Liasa/genética , ADN-(Sitio Apurínico o Apirimidínico) Liasa/metabolismo , Reparación del ADN/genética , Daño del ADN/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Endonucleasas/genética , Hominidae/metabolismo , Proteínas de Arabidopsis/genéticaRESUMEN
Base excision repair and active DNA demethylation produce repair intermediates with DNA molecules blocked at the 3'-OH end by an aldehyde or phosphate group. However, both the physiological consequences of these accumulated single-strand DNAs break with 3'-blocked ends (DNA 3'-blocks) and the signaling pathways responding to unrepaired DNA 3'-blocks remain unclear in plants. Here, we investigated the effects of DNA 3'-blocks on plant development using the zinc finger DNA 3'-phosphoesterase (zdp) AP endonuclease2 (ape2) double mutant, in which 3'-blocking residues are poorly repaired. The accumulation of DNA 3'-blocked triggered diverse developmental defects that were dependent on the ATM and RAD3-related (ATR)-suppressor of gamma response 1 (SOG1) signaling module. SOG1 mutation rescued the developmental defects of zdp ape2 leaves by preventing cell endoreplication and promoting cell proliferation. However, SOG1 mutation caused intensive meristematic cell death in the radicle of zdp ape2 following germination, resulting in rapid termination of radicle growth. Notably, mutating FORMAMIDOPYRIMIDINE DNA GLYCOSYLASE (FPG) in zdp ape2 sog1 partially recovered its radicle growth, demonstrating that DNA 3'-blocks generated by FPG caused the meristematic defects. Surprisingly, despite lacking a functional radicle, zdp ape2 sog1 mutants compensated the lack of root growth by generating anchor roots having low levels of DNA damage response. Our results reveal dual roles of SOG1 in regulating root establishment when seeds germinate with excess DNA 3'-blocks.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Reparación del ADN/fisiología , Factores de Transcripción/metabolismo , Arabidopsis/citología , Proteínas de Arabidopsis/genética , Proteínas de la Ataxia Telangiectasia Mutada/genética , Muerte Celular/genética , Proliferación Celular/genética , ADN de Plantas/genética , ADN de Plantas/metabolismo , ADN-Formamidopirimidina Glicosilasa/metabolismo , Endonucleasas/genética , Endonucleasas/metabolismo , Regulación de la Expresión Génica de las Plantas , Pleiotropía Genética , Germinación/genética , Meristema/citología , Meristema/genética , Células Vegetales , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Semillas/fisiología , Transducción de Señal , Factores de Transcripción/genéticaRESUMEN
A flexible, tough, highly transparent and piezoelectric polyacrylamide hydrogel was fabricated induced by blue light photocuring, with camphorquinone/diphenyliodonium hexafluorophosphate (CQ/DPI) as the blue light initiator, acrylamide (AM) and N,N-dimethylacrylamide (DMAA) as monomers, polyethylene glycol diacrylate (PEGDA) as the crosslinker, lecithin as the dispersant, and BaTiO3 as the piezoelectric material. Various performance tests were carried out on the hydrogel, and the results showed that lecithin enhances the dispersion of BaTiO3 within the system and improves the tensile properties (>100% strain) of the hydrogel, and the addition of PEGDA not only improves the photopolymerization performance of the hydrogel, but also significantly improves its fracture strength (â¼0.3 MPa). In addition, BaTiO3 enables the resultant hydrogels to show excellent conductivity (>1.5) and stable response to strain. The assembled hydrogel sensor shows a sensitive response to human joint activities, which is expected to be applied in self-powered sensors and energy collection.
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Objective: To investigate the clinical value of the expression levels of tumor protein D52 (TPD52) and miR-133a on the prognosis assessment of pancreatic cancer surgery. Methods: This was a retrospective study. Ninety-seven patients who underwent radical surgery for pancreatic cancer in Cangzhou Central Hospital from January 2018 to January 2022 were selected and divided into four groups: TPD52 high expression group, TPD52 low expression group, miR-133a high expression group and miR-133a low expression group. The relationship between the expression levels of TPD52 and miR-133a and the clinicopathological features of patients with pancreatic cancer was analyzed. The COX regression model was used to analyze the risk factors affecting the prognosis of patients with pancreatic cancer. Results: The high expression rate of TPD52 and the low expression rate of miR-133a in pancreatic cancer tissues were higher than those in normal paracancerous tissues(P<0.05). Based on the comparison of prognosis and survival, the median survival time of patients with high expression of TPD52 and low expression of miR-133a was lower than that of patients with low expression of TPD52 and high expression of miR-133a, with a statistically significant difference(P<0.05). Moreover, multivariate Cox regression analysis showed that low differentiation of pancreatic cancer, III-IV stage of TNM, high expression of TPD52, as well as low expression of miR-133a were independent risk factors for postoperative survival of patients with pancreatic cancer(P<0.05). Conclusion: TPD52 is expressed at a high level whereas miR-133a at a low level in pancreatic cancer tissues, both of which together with low differentiation of pancreatic cancer and III-IV stage of TNM constitute independent risk factors affecting the surgical prognosis of patients with pancreatic cancer.
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Aspirin (ASA) is a proven chemoprotective agent for colorectal cancer, though mechanisms underlying these effects are incompletely understood. Human organoids are an ideal system to study genomic and epigenomic host-environment interactions. We use human colonic organoids to profile ASA responses on genome-wide gene expression and chromatin accessibility. Human colonic organoids from one individual were cultured and treated in triplicate with 3 mM ASA or vehicle control (DMSO) for 24 h. Gene expression and chromatin accessibility were measured using RNA- and ATAC-sequencing, respectively. Differentially expressed genes were analyzed using DESeq2. Top genes were validated by qPCR. Gene set enrichment was performed by SetRank. Differentially accessible peaks were analyzed using DiffBind and edgeR. Peak annotation and differential transcription factor motifs were determined by HOMER and diffTF. The results showed robust transcriptional responses to ASA with significant enrichment for fatty acid oxidation and peroxisome proliferator-activated receptor (PPAR) signaling that were validated in independent organoid lines. A large number of differentially accessible chromatin regions were found in response to ASA with significant enrichment for Fos, Jun, and Hnf transcription factor motifs. Integrated analysis of epigenomic and genomic treatment responses highlighted gene regions that could mediate ASA's specific effects in the colon including those involved in chemoprotection and/or toxicity. Assessment of chromatin accessibility and transcriptional responses to ASA yielded new observations about genome-wide effects in the colon facilitated by application of human colonic organoids. This framework can be applied to study colonic ASA responses between individuals and populations in future studies.
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Aspirina , Epigenómica , Humanos , Aspirina/metabolismo , Colon/metabolismo , Cromatina/metabolismo , Factores de Transcripción/metabolismo , OrganoidesRESUMEN
Klebsiella pneumoniae carbapenemase (KPC) is a crucial enzyme that causes carbapenem resistance in Enterobacterales, and infections by these "superbugs" are extremely challenging to treat. Therefore, there is a pressing need for a rapid and accurate KPC detection test to control the prevalence of carbapenem-resistant Enterobacterales (CREs). In this study, we established a novel method for detection of blaKPC, the gene responsible for encoding KPC, based on a recombinase polymerase amplification (RPA) and a CRISPR/Cas13a reaction coupled to fluorophore activation (termed RPA-Cas13a assay). We carefully selected a pair of optimal amplification primers for blaKPC and achieved a lower limit of detection of approximately 2.5 copies/µL by repeatedly amplifying a recombinant plasmid containing blaKPC. The RPA-Cas13a assay demonstrated a sensitivity of 96.5% and specificity of 100% when tested on 57 blaKPC-positive CRE strains, which were confirmed by DNA sequencing. Moreover, in 311 sputum samples, the theoretical antibiotic resistance characteristics of blaKPC-positive strains obtained by the RPA-Cas13a assay were highly consistent with the results of antibiotic susceptibility test (Kappa = 0.978 > 0.81, P < 0.01). In conclusion, the RPA-Cas13a system is a simple and one-hour efficient technology for the detection of a potentially fatal antibiotic resistance gene.
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Gammaproteobacteria , Klebsiella pneumoniae , Klebsiella pneumoniae/genética , Carbapenémicos/farmacología , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Proteínas Bacterianas/genéticaRESUMEN
DNA methylation plays key roles in transposable element (TE) silencing and gene expression regulation. DNA methylation occurs at CG, CHG and CHH sequence contexts in plants. However, the synergistic and redundant roles of CG and non-CG methylation are poorly understood. By introducing CRISPR/Cas9-induced met1 mutation into the ddcc (drm1 drm2 cmt2 cmt3) mutant, we attempted to knock out all five DNA methyltransferases in Arabidopsis and then investigate the synergistic and redundant roles of CG and non-CG DNA methylation. We found that the homozygous ddcc met1 quintuple mutants are embryonically lethal, although met1 and ddcc mutants only display some developmental abnormalities. Unexpectedly, the ddcc met1 quintuple mutations only reduce transmission through the male gametophytes. The ddcc met1+/- mutants show apparent size divergence, which is not associated with difference in DNA methylation patterns, but associated with the difference in the levels of DNA damage. Finally, we show that a group of TEs are specifically activated in the ddcc met1+/- mutants. This work reveals that CG and non-CG DNA methylation synergistically and redundantly regulate plant reproductive development, vegetative development and TE silencing in Arabidopsis. Our findings provide insights into the roles of DNA methylation in plant development.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Metilación de ADN/genética , Elementos Transponibles de ADN/genética , Regulación de la Expresión Génica de las Plantas , Desarrollo de la PlantaRESUMEN
Active vitamin D, 1α,25(OH)2D3, is a nuclear hormone with roles in colonic homeostasis and carcinogenesis; yet, mechanisms underlying these effects are incompletely understood. Human organoids are an ideal system to study genomic and epigenomic host-environment interactions. Here, we use human colonic organoids to measure 1α,25(OH)2D3 responses on genome-wide gene expression and chromatin accessibility over time. Human colonic organoids were cultured and treated in triplicate with 100 nM 1α,25(OH)2D3 or vehicle control for 4 h and 18 h for chromatin accessibility, and 6 h and 24 h for gene expression. ATAC- and RNA-sequencing were performed. Differentially accessible peaks were analyzed using DiffBind and edgeR; differentially expressed genes were analyzed using DESeq2. Motif enrichment was determined using HOMER. At 6 h and 24 h, 2,870 and 2,721 differentially expressed genes, respectively (false discovery rate, FDR < 5%), were identified with overall stronger responses with 1α,25(OH)2D3. Similarly, 1α,25(OH)2D3 treatment led to stronger chromatin accessibility especially at 4 h. The vitamin D receptor (VDR) motif was strongly enriched among accessible chromatin peaks with 1α,25(OH)2D3 treatment accounting for 30.5% and 11% of target sequences at 4 h and 18 h, respectively (FDR < 1%). A number of genes such as CYP24A1, FGF19, MYC, FOS, and TGFBR2 showed significant transcriptional and chromatin accessibility responses to 1α,25(OH)2D3 treatment with accessible chromatin located distant from promoters for some gene regions. Assessment of chromatin accessibility and transcriptional responses to 1α,25(OH)2D3 yielded new observations about vitamin D genome-wide effects in the colon facilitated by application of human colonic organoids. This framework can be applied to study host-environment interactions between individuals and populations in the future.
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Calcitriol/farmacología , Colon/metabolismo , Epigenómica/métodos , Genómica/métodos , Organoides/metabolismo , Transcriptoma/efectos de los fármacos , Cromatina/efectos de los fármacos , Cromatina/genética , Cromatina/metabolismo , Secuenciación de Inmunoprecipitación de Cromatina/métodos , Humanos , Masculino , Persona de Mediana Edad , RNA-Seq/métodos , Factores de Tiempo , Activación Transcripcional , Vitamina D3 24-Hidroxilasa/genética , Vitaminas/farmacologíaRESUMEN
BACKGROUND: Browning spot (BS) disorders seriously affect the appearance quality of 'Huangguan' pear and cause economic losses. Many studies on BS have mainly focused on physiological and biochemical aspects, and the molecular mechanism remains unclear. RESULTS: In the present study, the structural characteristics of 'Huangguan' pear with BS were observed via scanning electron microscopy (SEM), the water loss and brown spots were evaluated, and transcriptomic and metabolomics analyses were conducted to reveal the molecular mechanism underlying 'Huangguan' pear skin browning disorder. The results showed that the occurrence of BS was accompanied by a decrease in the wax layer and an increase in lignified cells. Genes related to wax biosynthesis were downregulated in BS, resulting in a decrease in the wax layer in BS. Genes related to lignin were upregulated at the transcriptional level, resulting in upregulation of metabolites related to phenylpropanoid biosynthesis. Expression of calcium-related genes were upregulated in BS. Cold-induced genes may represent the key genes that induce the formation of BS. In addition, the results demonstrated that exogenous NaH2PO4·2H2O and ABA treatment could inhibit the incidence of BS during harvest and storage time by increasing wax-related genes and calcium-related genes expression and increasing plant resistance, whereas the transcriptomics results indicated that GA3 may accelerate the incidence and index of BS. CONCLUSIONS: The results of this study indicate a molecular mechanism that could explain BS formation and elucidate the effects of different treatments on the incidence and molecular regulation of BS.
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Metabolómica , Enfermedades de las Plantas/genética , Pyrus/genética , Pyrus/metabolismo , Transcriptoma/genética , Ácido Abscísico/farmacología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Redes Reguladoras de Genes/efectos de los fármacos , Giberelinas/farmacología , Metaboloma/genética , Modelos Biológicos , Fenotipo , Pyrus/efectos de los fármacos , Pyrus/ultraestructura , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factores de Transcripción/metabolismo , Transcriptoma/efectos de los fármacosRESUMEN
Base excision repair (BER) is essential for active DNA demethylation and DNA damage repair in mammals and plants. Here, we provide genetic and biochemical evidence that APURINIC/APYRIMIDINIC ENDONUCLEASE2 (APE2) plays overlapping roles with ZINC FINGER DNA 3'-PHOSPHOESTERASE (ZDP) in active DNA demethylation and DNA damage repair in Arabidopsis thaliana Simultaneous mutation of APE2 and ZDP causes DNA hypermethylation at more than 2000 loci, most of which are not hypermethylated in ape2 or zdp single mutants. The zdp and ape2 single mutants exhibit normal development, but the zdp ape2 double mutants display pleiotropic developmental defects and are supersensitive to the DNA alkylating reagent methyl methanesulfonate. The gradual accumulation of DNA lesions in the zdp ape2 seedlings is accompanied by constitutive activation of the DNA damage response and alteration of the cell cycle. Interestingly, knockout of the key DNA demethylase REPRESSOR OF SILENCING1 reduces the magnitude of DNA lesion accumulation and the DNA damage response in the zdp ape2 mutants, suggesting that a proportion of the DNA damage in the zdp ape2 mutants arises from incomplete active DNA demethylation. Lastly, we find that APE2 has 3'-phosphatase activity and strong 3'-5' exonuclease activity in vitro. Together, our results suggest that APE2 and ZDP, two BER proteins, play overlapping roles in the maintenance of epigenome and genome stability in plants.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Reparación del ADN/genética , Endonucleasas/fisiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiología , Daño del ADN/genética , Desmetilación del ADN , Endonucleasas/genética , Epigenómica , Inestabilidad Genómica/genética , Mutación/genéticaRESUMEN
To design a stable laser vision seam-tracking system, an advanced weld image processing algorithm based on Siamese networks is investigated and proposed to resist the interference of arc and spatter in the welding process. This specially designed neural network, combined with powerful feature expression capabilities of deep learning, takes two welding images with different sizes as inputs and generates a target confidence map in a single forward pass by using the cross-correlation algorithm. To prevent the error accumulation and model drift, an online update strategy via local cosine similarity is developed. The use of metal inert-gas welding can realize real-time and precious tracking under the condition that the strong arc continuously shields the welding seam feature points.
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Obesity is an established risk factor for many diseases including intestinal cancer. One of the responsible mechanisms is the chronic inflammation driven by obesity. However, it remains to be defined whether diet-induced obesity exacerbates the intestinal inflammatory status by cytokines produced in adipose tissue or the high fat diet first alters the gut microbiota and then drives intestinal inflammation. To address this question, we fed C57BL/6 mice with a high fat diet (HF, 60%) and sacrificed them sequentially after 8, 12, and 16 weeks, and then compositions of gut microbiota and expressions of antimicrobial peptides were determined. The compositions of gut microbiota were altered at 8 wk HF feeding, followed with reduced Paneth antimicrobial peptides lysozyme and Reg IIIγ after 12 and 16 wk HF feeding (p < 0.05), whereas elevations of circulating inflammatory cytokines IFNγ and TNF-α were observed until feeding a HF diet for 16 weeks (p < 0.05). These results indicated that high fat diet may stimulate intestinal inflammation via altering gut microbiota, and it occurs prior to the potential influence by circulating inflammatory cytokines. These findings emphasized the importance of microbiota, in addition to adipose tissue per se, in driving intestinal inflammation, which may thereafter promote intestinal tumorigenesis.
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Citocinas/metabolismo , Dieta Alta en Grasa/efectos adversos , Microbioma Gastrointestinal/fisiología , Células de Paneth/metabolismo , Péptidos/metabolismo , Animales , Western Blotting , Microbioma Gastrointestinal/genética , Inmunohistoquímica , Inflamación/inmunología , Inflamación/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Muramidasa/genética , Muramidasa/metabolismo , Obesidad/inmunología , Obesidad/metabolismo , Péptidos/genética , Ribonucleasa Pancreática/genética , Ribonucleasa Pancreática/metabolismoRESUMEN
OBJECTIVE: To characterize the phenotypes of spheno-occipital synchondrosis (SOS) in Chinese patients with Crouzon syndrome. METHODS: Twelve patients with Crouzon syndrome were included in this retrospective study, and were divided into 2 groups. The first group included 5 patients (5-7-year old), whereas 7 patients were included in the second group (8-11-year old). Two age- and sex-matched control groups were constituted for comparison. All patients and controls were underwent preoperative computed tomography examinations of the craniofacial area, and the three-dimensional skull models, sagittal, and axial images were reconstructed. The density of the SOS region was also calculated. RESULTS: The SOS was partially closed in the first Crouzon patients group, whereas the SOS was open in control groups. The SOS was completely fused SOS in the second Crouzon patients group, whereas the SOS was open or partially closed in control groups. There also were short and hypoplastic sphenoid bone in both Crouzon groups when compared with controls. In addition, the average density of SOS in patients with Crouzon syndrome was higher than the control groups (Pâ<0.01). CONCLUSIONS: The SOS begins to prematurely fuse in Chinese patients with Crouzon syndrome, and there are short and hypoplastic sphenoid bone in these patients. Although a definitive role of prematurely fused SOS in Crouzon syndrome cannot be drawn, our finds provide important clues into the mechanisms, and potentially provide a treatment target for midfacial and cranial vault hypoplasia in Crouzon patients.
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Anomalías Múltiples , Suturas Craneales/anomalías , Disostosis Craneofacial/diagnóstico , Imagenología Tridimensional , Hueso Occipital/anomalías , Hueso Esfenoides/anomalías , Tomografía Computarizada por Rayos X/métodos , Niño , Preescolar , Suturas Craneales/diagnóstico por imagen , Femenino , Humanos , Masculino , Hueso Occipital/diagnóstico por imagen , Fenotipo , Estudios Retrospectivos , Hueso Esfenoides/diagnóstico por imagenRESUMEN
Resveratrol (3,5,4'-trihydroxy-trans-stilbene, RSV), a natural polyphenolic compound, is known as a promising anti-cancer agent. In this study, we showed that RSV could inhibit the growth of B16 cells via induction of apoptosis. Moreover, our results showed for the first time that RSV induced autophagy in B16 cells, which might occur through ceramide accumulation and Akt/mTOR pathway inhibition. Inhibition of autophagy by an autophagic inhibitor 3-methyladenine (3-MA) or si-Beclin 1 enhanced RSV-induced cytotoxicity and apoptosis. Thus, autophagy inhibition represents a promising approach to improve the efficacy of RSV in the treatment of patients with melanoma.
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Ceramidas/metabolismo , Melanoma Experimental/tratamiento farmacológico , Melanoma Experimental/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Estilbenos/farmacología , Serina-Treonina Quinasas TOR/metabolismo , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/genética , Autofagia , Beclina-1 , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Técnicas de Silenciamiento del Gen , Melanoma Experimental/patología , Ratones , ARN Interferente Pequeño , Resveratrol , Transducción de Señal/efectos de los fármacosRESUMEN
Tetrabromobisphenol S (TBBPS) is a brominated flame retardants (BFRs). TBBPS is widely used as a new type of BFR to replace TBBPA. Here, we used gastric cells as a model for evaluating the effect of TBBPS on the toxicology of gastric cells. Biochemical assays such as indirect immunofluorescence, cell proliferation assay were performed to analyze the toxicological effects of TBBPS on gastric cells. Cell proliferation analysis showed that TBBPS caused inhibition of gastric cell proliferation, and TBBPS induced gastric cell death. Further analysis showed that TBBPS led to ferroptosis and senescence of gastric cells by detecting ferroptosis-related marker molecules. Further work showed that TBBPS treatment resulted in lowered ferritin expression alongside heightened transferrin levels, which may be a potential molecular mechanism for TBBPS-induced ferroptosis and senescence in gastric cells. Here, our team investigates the effects of TBBPS on gastric cells in an in vitro model, and found that TBBPS caused toxicological damage to gastric cells. This study indicates potential toxic effects of TBBPS on the gastric cells, thereby providing a basis for further research into the toxicology of TBBPS.
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Proliferación Celular , Senescencia Celular , Ferroptosis , Retardadores de Llama , Sobrecarga de Hierro , Senescencia Celular/efectos de los fármacos , Retardadores de Llama/toxicidad , Ferroptosis/efectos de los fármacos , Sobrecarga de Hierro/metabolismo , Sobrecarga de Hierro/patología , Humanos , Proliferación Celular/efectos de los fármacos , Inflamación/inducido químicamente , Inflamación/patología , Inflamación/metabolismo , Mucosa Gástrica/efectos de los fármacos , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patología , Línea Celular , Bifenilos Polibrominados/toxicidad , Estómago/efectos de los fármacos , Estómago/patología , Ferritinas/metabolismoRESUMEN
Membrane with remarkable proton conductance and selectivity plays a key role in obtaining high vanadium flow battery (VFB) performance. In this work, the trade-off effect between proton conductance and vanadium ion blocking was overcome by the introduction of a cross-linking structure to prepare covalent cross-linked fluorine-containing sulfonated polyimide (CFSPI-PVA) membranes. Herein, the CFSPI-PVA-15 membrane possesses excellent comprehensive properties, including acceptable area resistance (0.21 Ω cm2), lower vanadium ion permeability (0.76 × 10-7 cm2 min-1), and remarkable proton selectivity (3.11 × 105 min cm-3) compared with the commercial Nafion 212 membrane. At the same time, the CFSPI-PVA-15 membrane exhibits higher coulomb efficiencies (97.26%-99.34%) and energy efficiencies (68.65%-88.11%) and a longer self-discharge duration (29.2 h) in contrast with the Nafion 212 membrane. Moreover, 500 cycles of the CFSPI-PVA-15 membrane at 160 mA cm-2 are also stably executed. The internal reasons for the improved chemical stability of the CFSPI-PVA-15 membrane are clarified from theoretical calculations with the mean square displacement value and fractional free volume. Therefore, the CFSPI-PVA-15 membrane exhibits great potential for application in VFB.
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With rapid urbanization and human activities exacerbating threats to the degradation of various ecosystem services in modern urban agglomerations, the exploration of the state of ecological security at the scale of urban agglomerations is of great significance. This study considered the Lanzhou-Xining Urban Agglomeration as the research area, based on the land use data in 2000, 2005, 2010, 2015, and 2020. At the same time, the landscape ecological risk index was introduced. The land use change characteristics of the Lanzhou-Xining Urban Agglomeration were analyzed by using the land use transfer matrix, the value per unit area equivalent factor method, and the bivariate spatial autocorrelation analysis method to elucidate the impacts of the changes in the ecological risk index induced by the land use transition on the value of ecosystem services. This study analyzed the land use change characteristics of the Lanzhou-Xining Urban Agglomeration and elucidated the impacts of changes in the ecological risk index on the value of ecosystem services caused by land use transformation. The results showed that:â During the period from 2000 to 2020, the land use types of the Lanzhou-Xining Urban Agglomeration were mainly dominated by grassland, cropland, and forest land. The construction land area had expanded significantly mainly from cropland and grassland, and the six land use types had strong cross-transformation. The total area of land use change was 6 646.05 km2. â¡ In terms of spatial changes, the spatial pattern of ecosystem service value in the Lanzhou-Xining Urban Agglomeration had not undergone obvious transformation. However, the regional variability was significant, generally showing the distribution characteristics of high in the northwest and low in the southeast. â¢From the perspective of temporal change, the value of ecosystem services in the Lanzhou-Xining Urban Agglomeration showed an upward trend, with the total flow of value increasing from 186.459 billion yuan to 192.156 billion yuan, with a total value-added of 5.697 billion yuan. ⣠There was a rising trend in the overall ecological risk index of the Lanzhou-Xining Urban Agglomeration over the past 20 years. Low ecological risk areas and lower ecological risk areas dominated the ecological risk areas. There was a significant positive correlation between the value of ecosystem services and the ecological risk index. This study aimed to reveal the understanding of the impacts of land-use practices on ecosystem service values and ecological risks, to provide important references for regional ecological risk management and land-use policy formulation, and thus to promote the high-quality development of the ecological environment in the Yellow River Basin.
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DNA damage, which may arise from cellular activities or be induced by genotoxic stresses, can cause genome instability and significantly affect plant growth and productivity. In response to genotoxic stresses, plants activate the cellular DNA damage response (DDR) to sense the stresses and activate downstream processes. The transcription factor SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a functional counterpart of mammalian p53, is a master regulator of the DDR in plants. It is activated by various types of DNA lesions and can activate the transcription of hundreds of genes to trigger downstream processes, including cell cycle arrest, DNA repair, endoreplication, and apoptosis. Since SOG1 plays a crucial role in DDR, the activity of SOG1 must be tightly regulated. A recent study published in Plant Cell (Chen et al., Plant Cell koad126, 2023) reports a novel mechanism by which the ATR-WEE1 kinase module promotes SOG1 translation to fine-tune replication stress response.
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To achieve China's "double carbon" goal, it is necessary to make quantitative evaluation of the power grid enterprises' contribution to carbon emission reduction. This paper analyzes the contribution of power grid enterprises to carbon emission reduction from three points: power generation side, power grid side, and user side. Then, PLS-VIP method is used to screen the key influencing factors of carbon emission reduction contribution of power grid enterprises from three aspects: consumption of clean energy emission reduction, reduction of line loss emission reduction, and substitution of electric energy. Based on GA-ELM combined machine learning algorithm, we establish an intelligent evaluation model of power grid enterprises' carbon emission reduction contribution. Furthermore, according to the distribution law of key influencing factors, this paper uses Monte Carlo simulation method to calculate the contribution of power grid enterprises to carbon emission reduction by scenario, so as to evaluate the contribution of power grid enterprises to carbon emission reduction. Finally, combined with the relevant data of power grid enterprises from 2003 to 2019, this paper makes an empirical study on the completion of carbon emission reduction contribution and the promotion path.
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Contaminación del Aire , Carbono , Electricidad , Carbono/análisis , China , Industrias , Contaminación del Aire/prevención & controlRESUMEN
In this study, a double-loop tracking control strategy is investigated to realize trajectory tracking control for a wheeled mobile robot (WMR) with unmodeled dynamics. More specifically, two nonlinear ESOs are designed to estimate disturbances from external disturbances and unmodeled dynamics. Combining with integral sliding mode control and backstepping control, a double-loop tracking controller is designed to enhance tracking accuracy for the WMR along the right angle roads. Based on Lyapunov methods, convergence analysis is given for both the nonlinear ESOs and the double-loop tracking controller. Validity of the double-loop tracking control strategy is demonstrated by experimental results on the WMR along a right angle road.