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In recent years, ultrasound has emerged as a widely used technology for modifying proteins/peptides. In this study, we focused on the intrinsic mechanism of ultrasound-induced modification of bovine liver peptides, which were treated with ultrasound power of 0, 100, 200, 300, 400, and 500 W, and their physicochemical and functional properties, as well as ultrastructures, were investigated. The results show that ultrasound mainly affects hydrogen bonding and hydrophobic interactions to change the conformation of proteins and unfolds proteins through a cavitation effect, leading to an increase in biological activity. Fourier infrared spectroscopy showed that ultrasound inhibited the formation of hydrogen bonds and reduced intermolecular cross-linking. Molecular weight distribution showed that the antioxidant components of bovine liver polypeptides were mainly concentrated in fractions of 500-1,000 Da. Maximum values of ABTS (82.66 %), DPPH (76.02 %), chelated iron (62.18 %), and reducing power (1.2447) were obtained by treating bovine liver polypeptides with 500 W ultrasound. Combined with the scanning electron microscopy results, with the intervention of ultrasound, the impact force generated by ultrasonication may lead to the loosening of the protein structure, which further promotes the release of antioxidant peptides, and these findings provide new insights into the application of ultrasound in the release of antioxidant peptides from bovine liver.
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To reveal the interaction of oxidative stress and protein S-nitrosylation on mitochondrial pathway apoptosis and tenderness development in postmortem yak meat. Herein, we selected yak longissimus dorsi muscle as the research object and treated hydrogen peroxide (H2O2) with S-nitrosoglutathione agent (GSNO) as well as Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) in mixed injections with 0.9 % saline as a control group, followed by incubation at 4 °C for 12, 24, 72, 120 and 168 h. Results showed that this interaction significantly increased mitochondrial ROS and NO content (P < 0.05) while weakening the antioxidant capacity of GSH and TRX redox response systems or accelerating the Ca2+ release process, leading to mitochondrial functional impairment and increased apoptosis rate. Notably, the H2O2 + L-NAME group showed more pronounced apoptosis. Hence, we suggest that the interaction between oxidative stress and protein S-nitrosylation could positively regulate yak meat tenderization.
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Apoptosis , Peróxido de Hidrógeno , Estrés Oxidativo , Animales , Apoptosis/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Bovinos , Peróxido de Hidrógeno/metabolismo , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , NG-Nitroarginina Metil Éster/farmacología , Músculo Esquelético/metabolismo , Músculo Esquelético/efectos de los fármacos , Óxido Nítrico/metabolismo , Carne/análisis , Cambios Post Mortem , Especies Reactivas de Oxígeno/metabolismo , S-Nitrosoglutatión/farmacología , S-Nitrosoglutatión/metabolismo , Antioxidantes/metabolismo , Antioxidantes/farmacologíaRESUMEN
In this study, based on the evaluation of fishy value and sensory evaluation, this study determined that soaking in a 1% salt solution for 60 min had a significant impact on the deodorization of beef liver (p < 0.05). The results showed that salt infiltration promoted the release of fishy substances, improving the edible and processing performance of beef liver. The identification of flavor compounds in raw and roasted beef liver via GC-IMS implies that (E)-2-octenal-M, (E)-3-penten-2-one-M, ethyl acetate-M, ethyl acetate-D, and methanethiol are closely related to improving the flavor of beef liver; among them, (E)-2-octenal-M, (E)-3-penten-2-one-M, and methanethiol can cause beef liver odor, while nonanal-M, octanal-M, benzene acetaldehyde, n-hexanol-D, butyl propanoate-M, heptanal-D, heptanal-M, and 3-methylthiopropanal-M had significant effects on the flavor formation of beef liver steak. The determination of reducing sugars revealed that salt soaking had no significant effect on the reducing sugar content of beef liver, and the beef liver steak was significantly reduced (p < 0.05), proving that reducing sugars promoted the formation of beef liver steak flavor under roasting conditions. Fatty acid determination revealed that salt soaking significantly reduced the content of polyunsaturated fatty acids in beef liver (p < 0.05), promoting the process of fat degradation and volatile flavor production in the beef liver steak. Salt plays a prominent role in salting-out and osmosis during deodorization and flavor improvement. Through controlling important biochemical and enzymatic reactions, the release of flavor substances in a food matrix was increased, and a good deodorization effect was achieved, which lays a foundation for further research on the deodorization of beef liver and the flavor of beef liver steak.
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Craniofacial sutures play a crucial role beyond being fibrous joints connecting craniofacial bones; they also serve as the primary niche for calvarial and facial bone growth, housing mesenchymal stem cells and osteoprogenitors. As most craniofacial bones develop through intramembranous ossification, the sutures' marginal regions act as initiation points. Due to this significance, these sutures have become intriguing targets in orthopedic therapies like spring-assisted cranial vault expansion, rapid maxillary expansion, and maxillary protraction. Under orthopedic tracing force, suture stem cells are rapidly activated, becoming a dynamic source for bone remodeling during expansion. Despite their importance, the physiological changes during bone remodeling periods remain poorly understood. Traditional sectioning methods, primarily in the sagittal direction, do not capture the comprehensive changes occurring throughout the entire suture. This study established a standard mouse model for sagittal suture expansion. To fully visualize bone remodeling changes post-suture expansion, the PEGASOS tissue clearing method was combined with whole-mount EdU staining and calcium chelating double labeling. This allowed the visualization of highly proliferating cells and new bone formation across the entire calvarial bones following expansion. This protocol offers a standardized suture expansion mouse model and a 3-D visualization method, shedding light on the mechanobiological changes in sutures and bone remodeling under tensile force loading.
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Desarrollo Óseo , Suturas , Animales , Ratones , Biofisica , Remodelación Ósea , Calcio , Modelos Animales de EnfermedadRESUMEN
Modified Mn-Ce/P84 catalytic filter material can be used to achieve high removal efficiency of NOx and 1,2-DCBz in bag-filtering dust precipitator synergistic removal of multiple pollutants. However, the presence of SO2 in the actual industrial flue gas has an adverse impact on the catalytic performance of the catalytic filter material. In this paper, a kind of Mn-Ce catalytic filter material was prepared by the impregnation method, which was modified by Fe, Cu, and Co, respectively. As a result, the sulfur resistance of the catalytic filter material was improved. The change of catalytic activity of the three kinds of modified catalytic filter material at different concentrations was compared in the SO2 flue gas fixed bed system. And the modified catalytic filter materials were characterized by SEM, BET, XPS, XRD, and H2-TPR. When the temperature was over 80 °C, different concentrations of SO2 were injected into the simulated flue gas to test the denitrification activity of the catalytic filter material. The results showed that under the low SO2 concentration of 150 ppm, the denitrification activity and 1,2-DCBz activity of Fe, Co, and Cu-modified filter material were increased, and the sulfur resistance of Fe was better under the flue gas conditions of 300 ppm and 450 ppm SO2. Under the condition of 450 ppm SO2 and 200 °C reaction, 93.4% denitrification efficiency and 96.1% 1,2-DCBz removal efficiency could be achieved by using modified Fe-Mn-Ce catalytic filter material.
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Catecoles , Desnitrificación , Catálisis , AzufreRESUMEN
A small-angle neutron scattering (SANS) instrument at the China Spallation Neutron Source (CSNS) is an operating instrument for studying structures and inhomogeneities with dimensions ranging from 1 to 100 nm. Preparing multiple samples at once and measuring them sequentially is a common approach in SANS experiments to reduce neutron beamline wastes and increase experimental efficiency. We present the development of an automatic sample changer for the SANS instrument, including system design, thermal simulation, optimization analysis, structure design details, and temperature control test results. It features a two-row construction that can hold 18 samples on each row. The controllable temperature range is -30 to 300 °C. Furthermore, neutron scattering experiments on SANS at CSNS proved that this instrument has good temperature control performance and low background. This automatic sample changer is optimized for usage at SANS and will be offered to other researchers through the user program.
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Neutrones , Sincrotrones , Temperatura , Dispersión del Ángulo Pequeño , Simulación por Computador , Difracción de NeutronesRESUMEN
mercury emission control from flue gas is a crucial issue for environment protection. Alumina is an important alkali metal oxide for mercury adsorption in particulate, meanwhile is the potential adsorbent for mercury removal. The cognition on mercury heterogeneous reaction mechanism with alumina in presence of hydrogen chloride is inadequate. In this work, the DFT calculation was applied to detect mercury's chlorides adsorption on α-Al2O3 (001) surface, the Bader charge analysis was used to estimate electron transfer and the transition state theory was used to clarify reaction pathway and energy barrier, besides, the kinetic analysis based on Gibbs free energy was conducted to study the impact of temperature on chemical reaction. The results show that Hg can be captured by weak chemisorption on α-Al2O3 (001) surface with the adsorption energy of -56.37 kJ/mol, HgCl, HgCl2 are intensively bonded on surface with adsorption energies of -276.90 kJ/mol and -231.87 kJ/mol, the surface unsaturated Al and O atoms are the active sites. Charge transfer and PDOS analysis prove that the forming of covalent bonding is responsible for Hg species adsorption. Two possible reaction pathways of Hg oxidization to HgCl2 are discussed, in which a smaller energy barrier of 0.1 eV implies the dominant pathway 1 via Eley-Rideal mechanism: two adsorbed HCl molecules dissociate on surface and then react with one Hg atom. High temperature can promote the reaction rate constants of pathway 1 and 2, but is only favorable for reducing energy barrier of pathway 2.
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Mercurio , Mercurio/análisis , Mercurio/química , Adsorción , Cinética , Óxidos , Óxido de AluminioRESUMEN
α-MnO2 was in-situ supported onto silica coated magnetite nanoparticles (MagS-Mn) to study the adsorption and oxidation of Hg0 as well as the effecting patterns of SO2 and O2 on Hg0 removal. MagS-Mn showed Hg0 removal capacity of 1122.6 µg/g at 150 °C with the presence of SO2. Hg0 adsorption and oxidation efficiencies were 2.4% and 90.6%, respectively. Hg0 removal capability deteriorated at elevated temperatures. Surface oxygen and manganese chemistry analysis indicated that SO2 inhibited the Hg0 removal through consumption of adsorbed oxygen and reduction of high valence manganese. This inhibiting effect was observed to be counteracted by O2 at lower temperatures. O2 tended to compete with SO2 for active sites and further create additional adsorbed oxygen sites for Hg0 surface reaction via surface dissociative adsorption rather than replenish the active sites consumed by SO2. The high valence manganese was also preserved by O2 which was essential to Hg0 oxidation. The intervention of O2 in the inhibition of SO2 on Hg0 removal was weakened at temperatures higher than 250 °C. Aa a result, Hg0 tends to be catalytic oxidized in the condition of low reaction temperatures and with the presence of O2 over α-MnO2 oriented composites.
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Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China, and its components, which include ultrafine particles (UFPs), volatile organic compounds (VOCs), and other reactive gases, such as NH3 and NOx, are the most harmful to human health. China has released various regulations and standards to address pollution from mobile and stationary sources. Thus, it is urgent to develop online monitoring technology for atmospheric pollution source emissions. This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years. These instruments have been applied to monitor emissions from motor vehicles, ships, airports, the chemical industry, and electric power generation. Not only has the level of atmospheric environment monitoring technology and equipment been improving, but relevant regulations and standards have also been constantly updated. Meanwhile, the developed instruments can provide scientific assistance for the successful implementation of regulations. According to the potential problem areas in atmospheric pollution in China, some research hotspots and future trends of atmospheric online monitoring technology are summarized. Furthermore, more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.
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Contaminantes Atmosféricos , Contaminación del Aire , Compuestos Orgánicos Volátiles , Humanos , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , China , Monitoreo del Ambiente , Material Particulado/análisis , Tecnología , Emisiones de Vehículos/análisis , Compuestos Orgánicos Volátiles/análisisRESUMEN
Mammalian teeth develop from the inductive epithelial-mesenchymal interaction, an important mechanism shared by many organs. The cellular basis for such interaction remains elusive. Here, we generate a dual-fluorescence model to track and analyze dental cells from embryonic to postnatal stages, in which Pitx2+ epithelium and Msx1+ mesenchyme are sufficient for tooth reconstitution. Single-cell RNA sequencing and spatial mapping further revealed critical cellular dynamics during molar development, where tooth germs are organized by Msx1+Sdc1+ dental papilla and surrounding dental niche. Surprisingly, niche cells are more efficient in tooth reconstitution and can directly regenerate papilla cells through interaction with dental epithelium. Finally, from the dental niche, we identify a group of previously unappreciated migratory Msx1+ Sox9+ cells as the potential cell origin for dental papilla. Our results indicate that the dental niche cells directly contribute to tooth organogenesis and provide critical insights into the essential cell composition for tooth engineering.
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Diente , Diente/crecimiento & desarrolloRESUMEN
Antibiotic resistance is increasingly becoming a challenge to public health. The regulation of bacterial metabolism by post-translational modifications (PTMs) has been widely studied. However, the mechanism underlying the regulation of acetylation in bacterial resistance to antibiotics is still unknown. Here, we performed a quantitative analysis of the acetylated proteome of a wild-type (WT) Escherichia coli (E. coli) sensitive strain and ampicillin- (Re-Amp), kanamycin- (Re-Kan), and polymyxin B-resistant (Re-Pol) strains. Based on bioinformatics analysis combined with biochemical validations, we found a common regulatory mechanism between the different resistant strains. Our results showed that protein acetylation negatively regulates bacterial metabolism to regulate antibiotic resistance and positively regulates bacterial motility. Further analyses revealed that key enzymes in various metabolic pathways were differentially acetylated. In particular, pyruvate kinase (PykF), a glycolytic enzyme that regulates bacterial metabolism, and its acetylated form were highly expressed in the three resistant strains and were identified as reversibly acetylated by the deacetylase CobB and the acetyl-transferase PatZ (peptidyl-lysine N-acetyltransferase). Results showed that PykF also could be acetylated by nonenzymatic acetyl phosphatase (AcP) in vitro. Furthermore, the deacetylation of Lys413 in PykF increased PykF enzymatic activity by changing the conformation of its ATP binding site, resulting in an increase in energy production which, in turn, increased the sensitivity of drug-resistant strains to antibiotics. This study provides novel insights for understanding bacterial resistance and lays the foundation for future research on the regulation of acetylation in antibiotic-resistant strains. IMPORTANCE The misuse of antibiotics has resulted in the emergence of many antibiotic-resistant strains which seriously threaten human health. Protein post-translational modifications, especially acetylation, tightly control bacterial metabolism. However, the comprehensive mechanism underlying the regulation of acetylation in bacterial resistance remains unexplored. Here, acetylation was found to positively regulate bacterial motility and negatively regulate energy metabolism, which was common in all antibiotic-resistant strains. Moreover, the acetylation and deacetylation process of PykF was uncovered, and deacetylation of the Lys 413 in PykF was found to contribute to bacterial sensitivity to antibiotics. This study provides a new direction for research on the development of bacterial resistance through post-translational modifications and a theoretical basis for developing antibacterial drugs.
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Escherichia coli , Lisina Acetiltransferasas , Humanos , Escherichia coli/genética , Lisina/química , Acetilación , Procesamiento Proteico-Postraduccional , Antibacterianos/farmacología , Lisina Acetiltransferasas/metabolismo , Piruvato Quinasa/metabolismo , Farmacorresistencia MicrobianaRESUMEN
In the current study, a novel kind of mixed-mode hydrophobic/hydrophilic hybrid silica material has been developed for the solid-phase extraction of hydrophobic and hydrophilic illegal additives from food samples. A hydrophobic hybrid silica material was first prepared by the sol-gel method with tetraethoxysilane, 3-aminopropyltriethoxysilane, and dimethyloctadecyl-[3-(trimethoxysilyl)propyl] ammonium chloride (DTSACl) as precursors. Subsequently, the hydrophobic hybrid silica material was activated by glutaraldehyde, followed by the covalent immobilization of polyethyleneimine (PEI). PEI and the octadecyl group of DTSACl produced the hydrophilic/hydrophobic features of the hybrid silica material. The developed material was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance, zeta potential analyzer, and laser diffraction particle size analyzer, then applied as a hydrophobic and hydrophilic sorbent for the solid-phase extraction (SPE) of benzodiazepines from ginseng amino acid oral liquid as well as melamine and cyromazine from powdered milk, followed by RPLC/HILIC-MS/MS analysis. The composition and volumes for SPE loading and elution solutions were optimized in detail. Coupled with RPLC/HILIC-MS/MS, the proposed method provided satisfactory linearity in the range from 0.9-3.2 µg kg-1 to 100-250 µg kg-1 with the coefficients of determination higher than 0.99. The limits of detection ranged from 0.3 to 1.0 µg kg-1, and the recoveries ranged from 81.1% to 109.0% with the relative standard deviations less than 8.5% (n = 3). This report offers a new mixed-mode hydrophobic/hydrophilic hybrid silica material to extract trace hydrophobic and hydrophilic additives from complex samples.
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Dióxido de Silicio , Espectrometría de Masas en Tándem , Animales , Interacciones Hidrofóbicas e Hidrofílicas , Leche , Dióxido de Silicio/química , Extracción en Fase Sólida/métodosRESUMEN
The mechanochemical (MC) brominated fly ash is a cost-effective mercury removal adsorbent, in which unburned carbon (UBC) plays an important role. The MC bromination mechanism of UBC and its mercury removal mechanism were completely studied through the density functional theory (DFT) method. Various defects on zigzag and armchair edge models were constructed at the micro-scale to simulate the MC effect on UBC at the macro-scale. The results reveal that the intact surface of zigzag and armchair can be constructed into abundant defective structures by MC action. Compared with the complete surface, bromine is more favorable to bind on the defective surface, resulting in more and stronger C-Br covalent bonds and more active sites. These defective structures also have a promoting effect on mercury adsorption. For the bromine-embedded structure, although the appropriate defective structure accounts for less, it not only can promote the adsorption and oxidation of mercury by improving adsorption ability or decreasing the oxidation energy barrier but is also easier to generate. Due to defect types formed by MC interaction on the UBC surface are much more diverse and complex, this study provides the theoretical basis for further research.
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Ceniza del Carbón , Mercurio , Adsorción , Carbono , HalogenaciónRESUMEN
Current approaches for Mechanochemical bromination (MCB) modified fly ash have been focusing on the efficiency and mechanism of mercury removal, but the MCB activation mechanism is still not clear. Selecting activated carbon (AC), hematite (He), anatase (An), and mullite (Mu) to simulate four main fly ash components, and the above samples were MCB modified by omni-directional planetary ball mill with NaBr crystal as modifier. Based on the physicochemical properties and mercury removal ability of each pure component before and after modification, the activation mechanism of MCB was obtained. The results indicate that single mechanochemical modification has almost no effect on the mercury removal ability of each component. The mercury removal ability of fly ash improved by MCB is mainly due to the C-Br generated by reaction between NaBr and AC, and the covalently bonded Br (M-Br) on He also provides a certain contribution. However, the contribution of An and Mu is a little. The MCB activation mechanism is verified that original AC and He are firstly converted into unsaturated carbon and He with surface lattice defects by MCB process, then react with Br free radicals to form C-Br and M-Br, while An and Mu do not mechanochemically react with NaBr during the MCB process.
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Ceniza del Carbón , Mercurio , Carbón Orgánico , HalogenaciónRESUMEN
Periodontal ligament stem cells (PDLSCs), as potential "seed cells" for periodontal tissue repair and regeneration, require to be expanded in vitro for a large scale. Senescence of PDLSCs occurred during long-term culture may compromise the therapeutic effects of PDLSCs. Medium supplements may be useful in antisenescence. However, the effects and mechanisms of vitamin C (Vc) treatment on PDLSCs during long-term culture are still unclear. In this study, we identified that Vc-treated PDLSCs cells maintained a slender morphology, higher growth rate and migration capacity, stemness, and osteogenic differentiation capability during a long-term culture. Moreover, we also identified that Notch3 was significantly upregulated during the cell senescence, and Vc treatment alleviated the senescence of PDLSCs through inhibition of Notch3 during long-term culture. In summary, Vc treatment suppressed PDLSCs senescence by reducing the expression of Notch3 and might be a simple and useful strategy to inhibit cellular senescence during the cell long-term culture.
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Ácido Ascórbico/administración & dosificación , Osteogénesis/genética , Ligamento Periodontal/crecimiento & desarrollo , Receptor Notch3/genética , Adolescente , Técnicas de Cultivo de Célula , Diferenciación Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Niño , Femenino , Humanos , Masculino , Ligamento Periodontal/citología , Ligamento Periodontal/metabolismo , Células Madre/citología , Células Madre/efectos de los fármacosRESUMEN
Hertwig's epithelial root sheath (HERS) plays indispensable roles in tooth root development, including controlling the shape and number of roots, dentin formation, and helping generate the cementum. Based on these characteristics, HERS cell is a potential seed cell type for tooth-related tissue regeneration. However, the application is severely limited by a lack of appropriate culture methods and small cell numbers. Methods: Here, we constructed a 3D culture method to expand functional HERS cells into spheroids, and investigated characteristics and application of dental tissue regeneration of these spheroids. HERS spheroids and HERS cells (2D monolayer culture) were compared in terms of biological characteristics (such as proliferation, self-renewal capacity, and stemness) in vitro and functions (including differentiation potential and inductive ability of dentin formation) both in vitro and in vivo. Further, transcriptome analysis was utilized to reveal the molecular mechanisms of their obvious differences. Results: HERS spheroids showed obvious superiority in biological characteristics and functions compared to 2D monolayers of HERS cells in vitro. In vivo, HERS spheroids generated more mineralized tissue; when combined with dental papilla cells (DPCs), HERS spheroids contributed to dentin-like tissue formation. Moreover, the generation and expansion of HERS spheroids rely to some degree on the HIF-1 pathway. Conclusion: HERS spheroid generation is beneficial for functional HERS cell expansion and can provide a useful cell source for further tooth regeneration and mechanistic research. Notably, HIF-1 pathway plays a critical role in HERS spheroid formation and function.
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Cultivo Primario de Células/métodos , Endodoncia Regenerativa/métodos , Esferoides Celulares/trasplante , Raíz del Diente/crecimiento & desarrollo , Animales , Diferenciación Celular/fisiología , Proliferación Celular , Autorrenovación de las Células , Dentina/metabolismo , Células Epiteliales/fisiología , Células Epiteliales/trasplante , Femenino , Factor 1 Inducible por Hipoxia/metabolismo , Modelos Animales , Odontogénesis/fisiología , Ratas , Regeneración , Esferoides Celulares/fisiología , Células Madre/fisiologíaRESUMEN
Background: The formation of dentin-pulp involves complex epithelial-mesenchymal interactions between Hertwig's epithelial root sheath cells (HERS) and dental papilla cells (DPCs). Earlier studies have identified some of the regulatory molecules participating in the crosstalk between HERS and DPCs and the formation of dentin-pulp. In the present study we focused on the role of HERS-secreted exosomes in DPCs and the formation of dentin-pulp. Specifically, we hypothesized that exosome-like vesicles (ELVs) might mediate the function of HERS and trigger lineage-specific differentiation of dental mesenchymal cells. To test our hypothesis, we evaluated the potential of ELVs derived from a HERS cell line (ELVs-H1) in inducing in vitro and in vivo differentiation of DPCs. Methods: ELVs-H1 were characterized using transmission electron microscopy and dynamic light scattering. The proliferation, migration, and odontoblast differentiation of DPCs after treatment with ELVs-H1, was detected by CCK8, transwell, ALP, and mineralization assays, respectively. Real time PCR and western blotting were used to detect gene and protein expression. For in vivo studies, DPC cells were mixed with collagen gel combined with or without ELVs and transplanted into the renal capsule of rats or subcutaneously into nude mice. HE staining and immunostaining were used to verify the regeneration of dentin-pulp and expression of odontoblast differentiation markers. Results: ELVs-H1 promoted the migration and proliferation of DPCs and also induced odontogenic differentiation and activation of Wnt/ß-catenin signaling. ELVs-H1 also contributed to tube formation and neural differentiation in vitro. In addition, ELVs-H1 attached to the collagen gel, and were slowly released and endocytosed by DPCs, enhancing cell survival. ELVs-H1 together with DPCs triggered regeneration of dental pulp-dentin like tissue comprised of hard (reparative dentin-like tissue) and soft (blood vessels and neurons) tissue, in an in vivo tooth root slice model. Conclusion: Our data highlighted the potential of ELVs-H1 as biomimetic tools in providing a microenvironment for specific differentiation of dental mesenchymal stem cells. From a developmental perspective, these vesicles might be considered as novel mediators facilitating the epithelial-mesenchymal crosstalk. Their instructive potency might be exploited for the regeneration of dental pulp-dentin tissues.
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Pulpa Dental/metabolismo , Dentina/metabolismo , Animales , Diferenciación Celular/fisiología , China , Papila Dental/metabolismo , Pulpa Dental/fisiología , Dentina/fisiología , Células Epiteliales/metabolismo , Transición Epitelial-Mesenquimal/fisiología , Exosomas/fisiología , Regeneración Tisular Guiada Periodontal/métodos , Humanos , Células Madre Mesenquimatosas , Ratones , Ratones Desnudos , Ratas , Regeneración/fisiología , Raíz del Diente/metabolismo , Vía de Señalización WntRESUMEN
Dental pulp is critical to maintain the vitality of a tooth. Regeneration of pulpo-dentinal complex is of great interest to treat pulpitis and pulp necrosis. In this study, through three-dimensional spheroid culture, a group of unique multipotent stem cells were identified from mouse dental papilla called multipotent dental pulp regenerative stem cells (MDPSCs). MDPSCs exhibited enhanced osteogenic/odontogenic differentiation capabilities and could form regenerative dentin and neurovascular-like structures that mimicked the native teeth in vivo. Further analysis revealed that CD24a was the bona fide marker for MDPSCs, and their expansion was highly dependent on the expression of a key transcriptional factor, Sp7. Last, CD24a+ cells could be detected in primary dental papilla in mice and human, suggesting that MDPSCs resided in their native niches. Together, our study has identified a previously unidentified group of multipotent pulp regenerative stem cells with defined molecular markers for the potential treatment of pulpitis and pulp necrosis.
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Diferenciación Celular , Pulpa Dental/citología , Regeneración , Células Madre/citología , Células Madre/metabolismo , Animales , Biomarcadores , Antígeno CD24/metabolismo , Niño , Femenino , Técnica del Anticuerpo Fluorescente , Perfilación de la Expresión Génica , Humanos , Inmunohistoquímica , Ratones , TranscriptomaRESUMEN
Reliable gaseous Hg(II) measurement is crucial to mercury emissions control from coal-fired flue gas, but Hg(II) sampling under SO2 condition could probably increase the uncertainty of sorbent traps. CaO-AcS synthesized from calcium acetate and porous support were previously demonstrated to be effective for Hg(II) trapping under SO2-free condition. This work further evaluated SO2 influence on its Hg(II) retention ability via integrating experimental and DFT computational studies. Increased breakthrough rate of HgCl2 was found in a two-section CaO-AcS trap under SO2 conditions. Significant basicity and porosity loss of CaO-AcS were attributed to the formation of agglomerate CaSO3. Hg0 release from CaO-AcS samples suggested potential reactions between Hg(II) and SO2. The detected HgO and Hg2SO4 species by Hg-TPD in CaO-AcS further confirmed this speculation. Moreover, both competition and reduction effects of SO2 on surface-bound Hg(II) species were substantiated by DFT calculations. SO2 showed a stronger interaction with CaO than HgCl2 because SO2 has a lower LUMO level and can accept electrons easier. Reaction pathways indicated Hg(II) was partially reduced to Hg2SO4 under SO2-deficient condition, or directly reduced to Hg0 under SO2-rich condition. This work fully proposed the SO2 influence mechanisms and improvement countermeasures for practical gaseous Hg(II) sampling.
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Manganese oxides with different crystallographic structures were investigated for gas-phase elemental mercury removal. The inherent thermal regeneration performance and mechanism of α- and γ-MnO2 were studied. The manganese dioxides were found to possess a mercury removal efficiency of higher than 96% even after 120 min mercury exposure except for ß-MnO2 which removed much less mercury than Mn2O3. The α-MnO2 was found to have a higher recyclability of mercury capture and better durability for regeneration than γ-MnO2. During the first 1 h of exposure, α-MnO2 showed an excellent mercury capacity of 128 µg/g over 5 regeneration cycles. While for γ-MnO2, the mercury capacity of the fifth cycle was reduced to 68.74 µg/g, which is much lower than 131.42 µg/g for the first cycle. The microstructure of α-MnO2 was maintained throughout regeneration cycles due to its capability to retain lattice oxygen. In comparison, γ-MnO2 experienced reconstruction and phase transformation induced by oxygen vacancies due to lattice oxygen loss during regeneration process, leading to a degradation in mercury capture. The α-MnO2 oriented composite was found to be better developed into a regenerable catalytic sorbent for mercury removal from flue gases of coal-fired power plants.