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Background and Aims Abnormalities in tryptophan (TRP) metabolism induce abdominal pain and intestinal motility disorders. The study of TRP metabolism in diarrhea-predominant-irritable bowel syndrome (IBS-D) is important for the prevention, diagnosis, and treatment of this disease. In this study, a rapid and reliable ultra performance liquid chromatography-mass spectrometry (UPLC-MS) method was established to quantify tryptophan-kynurenine (TRP-Kyn) metabolism in the colon of a rat model with IBS-D. Methods The proteins were precipitated by methanol, chromatographically separated on a Welch Ultimate® Polar RP column with a gradient elution for 12â¯min, and detected by high-resolution tandem mass spectrometry. Pure water were used as an alternative mechanism for standard calibration, and the stable structural analog 2-Cl-Phe was used as an internal standard. Results Within a certain range, the r of TRP, kynurenine (Kyn) and quinolinic acid (QA), kynurenic acid (KA) are greater than 0.99, were found to be accurate and precise. The metabolism of TRP was significantly up-regulated along the Kyn pathway in the IBS-D model rats and normalized after treatment with pivacurium bromide. Conclusion This study investigates the mechanisms of IBS-D gastrointestinal dysfunction from the perspective of colonic TRP metabolism, and also provides new directions for the diagnosis and therapeutic approach of this disease.
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OBJECTIVE: We aimed to explore the treatment effect and therapeutic mechanisms of baicalin in Alzheimer's disease (AD). METHODS: The AD rat model was established by intracerebroventricular injection of Aß1-40, with rats in the baicalin group receiving baicalin intraventricular injections. Morris Water Maze and Hematoxylin-eosin (H&E) Staining were employed to detect the successful model construction and baicalin treatment effect. The proteins extracted from the hippocampus were subjected to proteomics analysis. Bioinformatics technology was employed for differential protein screening, functional classification, and enrichment. Western Blot was employed to validate the expressions of differentially expressed proteins (DEPs) and the protein modification alternations. RESULTS: Water maze test confirmed the successful AD model construction and baicalin can improve learning and memory abilities. A total of 26 DEPs associated with 28 Gene Ontology (GO) functions were identified in the model and 32 DEPs were obtained between the baicalin group and the model. Bioinformatics analysis demonstrated that AD occurrence resulted in neuronal dysfunction and was associated with immune responses. The baicalin therapeutic effect on AD may be associated with metabolic processes, vitamin response, angiogenesis regulation, and fatty acid response. Immunoglobulin heavy constant mu (Ighm) and Immunoglobulin G2a (IgG2a) exhibited significant increases in AD and baicalin attenuated their expressions, while Fatty acid desaturase 1 (Fads1) exhibited a significantly diminished expression and baicalin could reverse the trend. Succinylation detection exhibited the differentially expressed at 35 kD between the model and baicalin group. CONCLUSION: Baicalin intervention may ameliorate cognitive impairment in AD rats by modulating the expressions of proteins and the succinylation modifications.
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Various diseases caused by harmful microorganisms and viruses have caused serious harm and huge economic losses to society. Thus, rapid detection of harmful microorganisms and viruses is necessary for disease prevention and treatment. Nanomaterials have unique properties that other materials do not possess, such as a small size effect and quantum size effect. Introducing nanomaterials into biosensors improves the performance of biosensors for faster and more accurate detection of microorganisms and viruses. This review aims to introduce the different kinds of biosensors and the latest advances in the application of nanomaterials in biosensors. In particular, this review focuses on describing the physicochemical properties of zero-, one-, two-, and three-dimensional nanostructures as well as nanoenzymes. Finally, this review discusses the applications of nanobiosensors in the detection of microorganisms and viruses and the future directions of nanobiosensors.
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Bacterias , Nanoestructuras , Virus , Animales , Nanoestructuras/química , Virus/química , Virus/aislamiento & purificación , Bacterias/química , Bacterias/aislamiento & purificación , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Microbiología de AlimentosRESUMEN
At the heart of the non-implantable electronic revolution lies ionogels, which are remarkably conductive, thermally stable, and even antimicrobial materials. Yet, their potential has been hindered by poor mechanical properties. Herein, a double network (DN) ionogel crafted from 1-Ethyl-3-methylimidazolium chloride ([Emim]Cl), acrylamide (AM), and polyvinyl alcohol (PVA) was constructed. Tensile strength, fracture elongation, and conductivity can be adjusted across a wide range, enabling researchers to fabricate the material to meet specific needs. With adjustable mechanical properties, such as tensile strength (0.06-5.30 MPa) and fracture elongation (363-1373%), this ionogel possesses both robustness and flexibility. This ionogel exhibits a bi-modal response to temperature and strain, making it an ideal candidate for strain sensor applications. It also functions as a flexible strain sensor that can detect physiological signals in real time, opening doors to personalized health monitoring and disease management. Moreover, these gels' ability to decode the intricate movements of sign language paves the way for improved communication accessibility for the deaf and hard-of-hearing community. This DN ionogel lays the foundation for a future in which e-skins and wearable sensors will seamlessly integrate into our lives, revolutionizing healthcare, human-machine interaction, and beyond.
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Lengua de Signos , Humanos , Alcohol Polivinílico/química , Monitoreo Fisiológico , Dispositivos Electrónicos Vestibles , Geles/química , Imidazoles/química , Técnicas Biosensibles , Acrilamida , Resistencia a la TracciónRESUMEN
We report the synthesis of poly(acrylamide-co-acrylic acid)/sodium carboxy methyl cellulose (PAMAA/CMC-Na) hydrogels, and subsequent fabrication of dual-network polymer hydrogels (PAMAA/CMC-Na/Fe) using as-prepared via the salt solution (FeCl3) immersion method. The created dual-network polymer hydrogels exhibit anti-swelling properties, frost resistance, high conductivity, and good mechanical performance. The hydrogel swells sightly when immersed in solution (pH = 2~11). With the increase in nAA:nAM, the modulus of elasticity experiences a rise from 1.1 to 1.6 MPa, while the toughness undergoes an increase from 0.18 to 0.24 MJ/m3. Furthermore, the presence of a high concentration of CMC-Na also contributes to the enhancement of mechanical strength in the resulting hydrogels, ascribing to enhanced physical network of the hydrogels. The minimum freezing point reaches -21.8 °C when the CMC-Na concentration is 2.5%, owing to the dissipated hydrogen bonds by the coordination of Fe3+ with carboxyl (-COO-) in CMC-Na and PAMAA. It is found that the conductivity of the PAMAA/CMC-Na/Fe hydrogels gradually decreased from 2.62 to 0.6 S/m as the concentration of CMC-Na rises. The obtained results indicates that the dual-network hydrogels with high mechanical properties, anti-swelling properties, frost resistance, and electrical conductivity can be a competitive substance used in the production of bendable sensors and biosensors.
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The utilization of solar interface evaporation technology (SIET) for freshwater production from seawater and sewage is a sustainable, green, viable, and promising approach. However, the absorption rate of sunlight, evaporation rates, and high costs still pose large-scale solar steam generation. In this paper, a novel aerogel (named SAS) was prepared by graft copolymerization with sodium alginate (SA), acrylic acid (AA) and sodium humate (SH) in aqueous solution, using N, N'-Methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator, which has high light absorption (90 %), high porosity (87.96 %), superhydrophilicity (35 ms), low thermal conductivity (0.23 W m-1 k-1). The evaporation rate of SAS aerogel can reach up to 1.66 kg m-2h-1 under 1 kW m-2 light intensity, and the reusability and reliability of SAS aerogel are verified by 10 cycles of experiments. The utilization of this SAS aerogel holds significant implications for the design and fabrication of cost-effective, high-performance solar steam evaporation systems, thereby offering promising solutions to address global freshwater shortages and enhance wastewater treatment efficiency.
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Objective@#To analyze the status of childhood bullying bystander s behaviors among pupils and the correlation with family function,so as to provide empirical support for educational intervention in campus bullying.@*Methods@#A questionnaire survey using the cluster random sampling method was administered to 1 145 pupils from a primary school in Wushan County within Chongqing City in November 2019, including Pupil Bullying Bystander Behavior Scale and Family Adaptability and Cohesion Evaluation Scale(FACES). The χ 2 test, Spearman related analysis and binary Logistic regression were used to determine the detection rate of different bullying bystander behaviors among pupils and the association with family function.@*Results@#The proportion of bullying promoters, bullying protectors, and bystanders were 4.7%, 92.1%, and 42.1%, respectively. There were statistically significant differences in the three types of bullying bystander s behaviors among the different grades pupils( χ 2=21.45, 7.98, 27.48, P < 0.05 ). There were significant correlation between family function and its dimensions with different types of bullying bystander behavior ( | r |= 0.07-0.20, P <0.05). Binary Logistic regression analysis showed that pupils family function and grade had statistically significant impact on promoting bullying behavior, protecting victim behavior, and bystander behavior ( OR =0.98, 3.33; 1.02, 1.95 ; 0.99, 0.58, 0.41, 0.61, P <0.05).@*Conclusions@#The bullying bystanders behaviors of pupils are related to grade in school and family function. Schools should implement educational interventions for pupils of different grades and focus on improving pupils family function to effectively promote the occurrence of positive bystanders behaviors in pupils.
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To meet full-field image quality requirements for extremely low aberration optical systems, an initial structure construction method for reflective optical systems based on full-field aberration correction is proposed. The aberration of the full field is used as the main evaluation criterion in this method. A multi-field evaluation function is established using the aberration values of multiple characteristic field points to represent the full-field imaging quality, and spatial ray tracing is introduced to constrain the optical system structure. Multi-objective optimization of the evaluation function is performed using a combinatorial nondominated sorting and metaheuristics algorithm; an initial optical system with a reasonable structure and corrected third-order aberrations over the full field is subsequently obtained. After optimization, an extreme ultraviolet lithography objective with a numerical aperture of 0.33 and root-mean-square wavefront error of 0.128 nm ($1/105\lambda, \lambda = 13.5\;{\rm nm}$) is obtained.
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Background: Ischemic stroke (IS) is a highly heterogeneous disease. Recent studies have shown that epigenetic variables affect the immune response. However, only a few studies have examined the relationship between IS and m6A immunoregulation. Therefore, we aim to explore the methylation of RNA mediated by m6A regulatory factor and the immune microenvironment characteristics of IS. Methods: Differentially expressed m6A regulators were detected in IS microarray datasets GSE22255 and GSE58294. We used a series of machine learning algorithms to identify key IS-related m6A regulators and validated them on blood samples of IS patients, oxygen-glucose deprivation/reoxygenation (OGD/R) microglia and GSE198710 independent data sets. Different m6A modification modes were determined and the patients were classified. In addition, we systematically associate these modification patterns with the characteristics of immune microenvironment, including infiltrating immune cells, immune function genes and immune response genes. Then we developed a model of m6A score to quantify the m6A modification in IS samples. Results: Through the analysis of the differences between the control group and IS patients, METTL16, LRPPRC, and RBM15 showed strong diagnostic significance in three independent data sets. In addition, qRT-PCR and Western blotting also confirmed that the expression of METTL16 and LRPPRC was downregulated and the expression of RBM15 was upregulated after ischemia. Two m6A modification modes and two m6A gene modification modes were also identified. m6A gene cluster A (high m6A value group) was positively correlated with acquired immunity, while m6A gene cluster B (low m6A value group) was positively correlated with innate immunity. Similarly, five immune-related hub genes were significantly associated with m6Acore (CD28, IFNG, LTF, LCN2, and MMP9). Conclusion: The modification of m6A is closely related to the immune microenvironment. The evaluation of individual m6A modification pattern may be helpful for future immunomodulatory therapy of anti-ischemic response.
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In this study, three cold-tolerant phenol-degrading strains, Pseudomonas veronii Ju-A1 (Ju-A1), Leifsonia naganoensis Ju-A4 (Ju-A4), and Rhodococcus qingshengii Ju-A6 (Ju-A6), were isolated. All three strains can produce cis, cis-muconic acid by ortho-cleavage of catechol at 12 â. Response surface methodology (RSM) was used to optimize the proportional composition of low-temperature phenol-degrading microbiota. Degradation of phenol below 160 mg L-1 by low-temperature phenol-degrading microbiota followed first-order degradation kinetics. When the phenol concentration was greater than 200 mg L-1, the overall degradation trend was in accordance with the modified Gompertz model. The experiments showed that the microbial agent (three strains of low-temperature phenol-degrading bacteria were fermented separately and constructed in the optimal ratio) could completely degrade 200 mg L-1 phenol within 36 h. The above construction method is more advantageous in bio-enhanced treatment of actual wastewater. Through the construction of microbial agents to enhance the degradation effect of phenol, it provides a feasible scheme for the biodegradation of phenol wastewater at low temperature and shows good application potential.
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Fenol , Aguas Residuales , Fenol/metabolismo , Temperatura , Fenoles/metabolismo , Frío , Biodegradación AmbientalRESUMEN
Flexible pressure sensors (FPSs) have been widely studied in the fields of wearable medical monitoring and human-machine interaction due to their high flexibility, light weight, sensitivity, and easy integration. To better meet these application requirements, key sensing properties such as sensitivity, linear sensing range, pressure detection limits, response/recovery time, and durability need to be effectively improved. Therefore, researchers have extensively and profoundly researched and innovated on the structure of sensors, and various microstructures have been designed and applied to effectively improve the sensing performance of sensors. Compared with single microstructures, multiple microstructures (MMSs) (including hierarchical, multi-layered and hybrid microstructures) can improve the sensing performance of sensors to a greater extent. This paper reviews the recent research progress in the design and application of FPSs with MMSs and systematically summarizes the types, sensing mechanisms, and preparation methods of MMSs. In addition, we summarize the applications of FPSs with MMSs in the fields of human motion detection, health monitoring, and human-computer interaction. Finally, we provide an outlook on the prospects and challenges for the development of FPSs.
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BACKGROUND AND PURPOSE: MicroRNAs (miRNAs) are highly expressed in the central nervous system and play important roles in ischaemic stroke pathogenesis. However, the role of miRNAs in cerebral ischaemia-reperfusion injury remains unclear. Here, we investigated the role of miR-140-3p in regulating oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neuronal injury in vitro to identify a new biomarker for research on ischaemic stroke. METHODS: The differential expression of miR-140-3p and Tyro3 in OGD/R-exposed N2a cells was verified by qRT-PCR. N2a cells were transfected with miR-140-3p mimic, miR-140-3p inhibitor, Tyro3 or siTyro3, and qRT-PCR, Western blotting, the Cell counting kit-8 (CCK-8) assay, Hoechst 33342/PI staining and flow cytometry analyses were performed to measure miRNA, mRNA and protein expression; cell viability; and apoptosis. RESULTS: OGD/R-exposed N2a cells exhibited increased miR-140-3p expression, decreased viability, reduced Bcl-2 protein expression and increased Bax and Caspase-3 protein expression and apoptosis; the miR-140-3p mimic markedly amplified these changes, exacerbating OGD/R-induced injury to N2a cells, while the miR-140-3p inhibitor reversed these changes and alleviated OGD/R-induced injury. OGD/R-exposed N2a cells expressed less Tyro3, and Tyro3 overexpression increased cell viability and Bcl-2 protein expression, reduced Bax and Caspase-3 protein expression, and alleviated OGD/R-induced injury. However, silencing Tyro3 reversed these changes and exacerbated OGD/R-induced injury. MiR-140-3p directly bound the Tyro3 mRNA 3'UTR. Rescue experiments indicated that the miR-140-3p mimic-induced changes in cell viability and protein expression were alleviated by Tyro3 overexpression and that the miR-140-3p inhibitor-induced changes in cell viability and protein expression were alleviated by silencing Tyro3. Tyro3 overexpression increased cell viability and PI3K and p-Akt protein expression, but these effects were weakened by the addition of LY294002. CONCLUSIONS: MiR-140-3p directly targets Tyro3 to regulate cell viability and apoptosis of OGD/R-exposed N2a cells through the PI3K/Akt pathway, suggesting that miR-140-3p is a novel biomarker and therapeutic target for ischaemic stroke.
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Isquemia Encefálica , Accidente Cerebrovascular Isquémico , MicroARNs , Daño por Reperfusión , Humanos , Apoptosis , Isquemia Encefálica/metabolismo , Caspasa 3 , Glucosa/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Oxígeno/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Proteínas Tirosina Quinasas Receptoras/farmacología , Daño por Reperfusión/metabolismo , ARN Mensajero , Accidente Cerebrovascular/patologíaRESUMEN
The present study focuses on the role of the long noncoding RNA (lncRNA) NEAT1 in regulating autophagy during the ischemiaâreperfusion (I/R) injury process and its possible regulatory mechanism based on the results of laboratory experiments. Neuro-2a (N2a) cells and BV-2 microglial cells were cultured separately, and oxygen-glucose deprivation/reoxygenation (OGD/R) was induced in vitro to mimic cerebral I/R injury. The expression of lncRNA NEAT1 was measured after reoxygenation for different durations, and the results showed that NEAT1 expression was significantly different after OGD/R for 12 h; thus, cell models of NEAT1 overexpression and knockdown were constructed. Knockdown of NEAT1 effectively relieved reperfusion injury. In an N2a and BV-2 cell coculture system, knockdown of NEAT1 reduced autophagic flow in neuronal cells after reperfusion. To clarify the mechanism of NEAT1 after neuronal I/R injury, label-free quantitative proteomics (LFQ) was used to identify the differentially expressed proteins (DEPs) in NEAT1 knockdown neurons after OGD/R for 12 h. Additionally, Gene Ontology (GO) enrichment, proteinâprotein interaction (PPI) network and parallel-reaction monitoring (PRM) quantitative analyses were carried out; the results showed that the expression levels of the autophagy-related proteins Gaa, Glb1, Prkaa1, Kif23, Sec24a and Vps25 were significantly reduced and that these proteins interact. In summary, this study shows that NEAT1 can regulate the interactions between autophagy-related proteins after neuronal I/R injury, reducing the level of autophagy and relieving neuronal reperfusion injury.
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MicroARNs , ARN Largo no Codificante , Daño por Reperfusión , Humanos , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Daño por Reperfusión/metabolismo , Reperfusión , Oxígeno/metabolismo , Proteínas Relacionadas con la Autofagia , Autofagia , Glucosa/metabolismo , Apoptosis/genética , MicroARNs/metabolismo , Proteínas de Transporte Vesicular/genéticaRESUMEN
Dopamine (DA) plays the role of the transmitter of information in the brain. Neurological diseases and depression are in close relationship with DA release. In this study, we developed a co-catalyst Zn0.2Cd0.8S@zeolitic imidazolate framework-67 (Zn0.2Cd0.8S@ZIF-67) to improve the photocatalyst efficacy of Rhodamine B (RhB) and electrochemical sensing of DA. Results show that Zn0.2Cd0.8S@ZIF-67 exhibits optimal photocatalytic activity with the addition of 80 mg ZIF-67. The degradation percentage of RhB by Zn0.2Cd0.8S@ZIF-67 reached 98.40% when the co-catalyst was 50 mg. Radical trapping experiments show that ·O2- played a significant role in the photocatalytic degradation of RhB. The catalytic mechanism of the Zn0.2Cd0.8S@ZIF-67 was found as a Z-type photocatalysis. Finally, a DA biosensor was constructed and displayed a high response and selectivity to DA. This can be attributed to the heterojunction between Zn0.2Cd0.8S and ZIF-67, which can significantly enhance the separation of e-/h+ and improve charge transfer. These findings will play a positive role in the in-situ monitoring of neurological diseases and depression.
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Aqueous lithium-ion batteries (LIBs) have attracted increasing attention because of their higher safety and nontoxicity compared to traditional LIBs. However, crucial shortcomings impede their practical applications. A narrow electrochemical window restricts the capacity of aqueous LIBs so the ultrahigh concentration electrolyte lithium bistrifluoromethosulfonimide (LiTFSI) is introduced to widen the electrochemical window in this work. With the addition of LiTFSI, the electrochemical window of the created aqueous LIBs is improved to 2 V. Moreover, the material design promotes the high density of aqueous LIBs, in which hollow Co3O4 nanocrystals obtained by the metal organic framework (MOF) template are connected with NiCo2O4 nanorods to form three-dimensional nanohybrids. The formed Co3O4/NiCo2O4 (CN) materials can provide NiCo2O4 channels for electron transfer between hollow Co3O4 which can offer more lithium-ions insertion. These effects work together synergistically to achieve aqueous LIBs with a wide electrochemical window and high energy density (93.07 W h kg-1 at 0.5 C). CN-6/LiMn2O4-based aqueous LIBs with LiTFSI as the electrolyte take into account both environmental friendliness and sustainable energy storage and exhibit great potential for producing novel clean energy storage devices from the concepts of material design and synthesis.
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2D nanomaterials show great potential in biomedical applications due to their unique physical and chemical surface properties. This review includes typical 2D nanomaterials used in bone tissue engineering (BTE), such as graphene oxide, hexagonal boron nitride, molybdenum disulfide, black phosphorus, and MXenes. Moreover, the construction methods of BTE materials with 2D nanosheets are analyzed. Before designing a BTE material, it is essential to understand the relationship between the material structure and properties. Notably, 2D nanomaterials can be hybridized with biomaterials, such as polypeptides, proteins, and polysaccharides, to improve biocompatibility and host responses. The effects of the surface properties and size of 2D nanomaterials on cellular behavior, gene expression, antibacterial properties, and cytotoxicity in BTE applications are also discussed. This work provides new design ideas and directions for constructing 2D nanomaterial-based BTE scaffolds.
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Nanoestructuras , Ingeniería de Tejidos , Nanoestructuras/química , Huesos , Materiales Biocompatibles , Andamios del TejidoRESUMEN
Hypoxia inducible factor 1α (HIF1α) has been reported to play a key role in protecting neurons from ischaemic injury. However, the exact molecular mechanisms remain largely unclear. PC12 cells were exposed to oxygen glucose deprivation/reoxygenation (OGD/R) conditions to mimic ischaemic injury in vitro. The expression of the HIF1α mRNA, miR20a5p, and kinesin family member 5A (KIF5A) mRNA was tested using qRT-PCR. Levels of the HIF1α, LC3I/II, P62, LAMP2, cathepsin B (CTSB) and KIF5A proteins were determined using western blotting. The CCK8 assay was conducted to assess PC12 cell viability. DQRedBSA and LysoSensor Green DND189 dyes were employed to measure the proteolytic activity and pH of lysosomes, respectively. The interaction between miR20a5p and HIF1α or KIF5A was verified by performing chromatin immunoprecipitation (ChIP) and/or dualluciferase reporter assays. TUNEL staining was adopted to assess PC12 cell death. GFPLC3 and RFPGFPLC3 probes were used to examine the autophagy status and autophagy flux of PC12 cells. A rat middle cerebral artery occlusionreperfusion (MCAO/R) model was established to investigate the role of the HIF1α/miR20a5p/KIF5A axis in ischaemic stroke in vivo. OGD/R exposure initiated PC12 cell autophagy and injury. HIF1α expression was substantially increased in PC12 cells after OGD/R exposure. Overexpression of HIF1α reversed the effects of OGD/R on reducing cell viability, blocking autophagy flux and inducing lysosome dysfunction. These rescue effects of HIF1α depended on KIF5A. HIF1α negatively regulated miR20a5p expression by targeting its promoter region, and miR20a5p directly targeted and negatively regulated the KIF5A mRNA. Overexpression of miR20a5p abolished the effects of HIF1α on rescuing OGD/Rinduced injury in PC12 cells. The effects of the HIF1α/miR20a5p/KIF5A axis were verified in MCAO/R rats. HIF1α protects PC12 cells from OGD/Rinduced cell injury by regulating autophagy flux through the miR20a5p/KIF5A axis.
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Isquemia Encefálica , Subunidad alfa del Factor 1 Inducible por Hipoxia , Cinesinas , MicroARNs , Daño por Reperfusión , Accidente Cerebrovascular , Animales , Apoptosis , Autofagia , Catepsina B , Supervivencia Celular , Glucosa/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Cinesinas/genética , MicroARNs/genética , Oxígeno , Células PC12 , ARN Mensajero , Ratas , Daño por Reperfusión/metabolismoRESUMEN
Dissimilatory nitrate reduction to ammonium (DNRA) can be used for nitrogen recovery. However, due to the low conversion efficiency of the DNRA process of microorganisms, the process cannot be industrially applied. Ascorbic acid (ASA) can improve DNRA efficiency of Escherichia coli sp. SZQ1 (E. coli). Experimental studies suggest that 10 g L-1 ASA promoted DNRA process of E. coli at high concentrations of nitrite (10-20 mM). In the 5 g L-1 ASA system, 9.2 mM nitrite was reduced to 8.21 mM ammonium by E. coli in 120 h. Mechanistic studies reveal that ASA reduced the oxidation-reduction potential (ORP) of the system and scavenged reactive oxygen species (ROS) in the cell of E. coli. Meanwhile, ASA was utilized by E. coli as the sole carbon source and provided electrons to DNRA process through ASA metabolic pathways. This study proposes a new strategy for increasing the efficiency of DNRA.
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Compuestos de Amonio , Compuestos de Amonio/metabolismo , Nitritos/metabolismo , Nitratos/metabolismo , Desnitrificación , Especies Reactivas de Oxígeno , Ácido Ascórbico , Escherichia coli/metabolismo , Oxidación-Reducción , Nitrógeno/metabolismo , Óxidos de Nitrógeno , CarbonoRESUMEN
Fluorescent carbon dots (CDs)-based nanomaterials exhibited promising potential in the fields of biomedicine, bioanalysis, and biosensors. In this work, multi-colored fluorescent carbonized polymer dots (CPDs) ranging from blue to red are obtained using different synthesis methods using citric acid and urea as raw materials, and the controllable synthesis of CPDs with multi-color fluorescence is successfully realized. Then, the photoluminescence (PL) mechanism of CPDs is studied using multiple characterization methods, and the key factors affecting the fluorescence emission wavelength of CPDs are discussed. It is shown that the fluorescence of the CPDs originates from three main components: the carbon nuclei in the intrinsic state, the functional groups in the surface state, and the molecular fluorophores adsorbed on the surface of the CPDs. The reaction temperature and reaction time affect the effective conjugation size of the carbon nuclei, which in turn affects the fluorescence redshift of CPDs; the reaction solvent greatly alters the surface state of CPDs (e.g. surface defects and functional groups), which leads to a significant redshift in the fluorescence of CPDs; the presence of molecular fluorophores facilitates the fluorescence redshift of CPDs. Finally, we have successfully applied the prepared red fluorescent CPDs for in vitro cell imaging. The study on the color regulation mechanism of CPDs is of great significance for the controllable preparation of high-performance fluorescent CDs and their application in the field of biomedicine.
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Polímeros , Puntos Cuánticos , Carbono , Ácido Cítrico , Fluorescencia , Colorantes Fluorescentes , Solventes , UreaRESUMEN
Drug-derived carbon dots (CDs) not only have excellent photoluminescence properties of CDs, but also maintain pharmacological effects of original drugs, so as to realize extended applications for both bioimaging and chemotherapy. In this work, metformin (Met)-derived CDs (Met-CDs) as multifunctional nanocarriers with tumor cell imaging and cancer therapy are synthesized using Met and citric acid as precursors. The created Met-CDs exhibit obvious resistance to photobleaching, significant pH sensitivity in acidic environments, good pH stability in alkaline environments, and high temperature sensitivity. In addition, we further investigate the biological activity of Met-CDs using diabetic cell models, which demonstrate the ability of Met-CDs to treat diabetes and reduce the production of reactive oxygen species in diseased cells. Subsequently, human alveolar adenocarcinoma basal epithelial cells (A549) are cultured in both normal glucose and low glucose media, and different concentrations of Met and Met-CDs are added to investigate the effect of Met-CDs on A549 cells. Finally, we successfully utilize the prepared Met-CDs to image live A549 cells in vitro in normal glucose medium. The Met-CDs prepared in this work reveal high potential to be used as both fluorescent probes and drug agents for tumor therapy, realizing controllable integrated diagnosis and treatment of diseases.