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Baccaurea ramiflora Lour. is a new kind of underutilized wild fruit tree; the metabolic reasons for its fruit flavor changes are not yet clear. In this study, the pink flesh of this excellent tasting fruit (BR) was used to reveal the metabolic causes of taste variations through five developmental stages. We identified 154 common differential metabolites of different developmental stages based on non-targeted metabolomics analysis. The accumulation of sugar and fatty acids increased significantly after 73 days, while citric acid decreased significantly. Flesh color accumulation mainly occurred 53 days ago, and vitamin accumulation occurred after 93 days. Interestingly, L-sorbose and 5-hydroxyindole-3-acetic acid were positively correlated with the sugar-acid ratio but negatively correlated with titratable acids. It indicated that L-sorbose and 5-hydroxyindole-3-acetic acid may be taste biomarkers of BR B. ramiflora. The results provided new metabolic lines of evidence for the taste variation during the ripening process of B. ramiflora.
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Artificial photoenzymes with novel catalytic modes not found in nature are in high demand; yet, they also present significant challenges in the field of biocatalysis. In this study, a chemogenetic modification strategy is developed to facilitate the rapid diversification of photoenzymes. This strategy integrates site-specific chemical conjugation of various artificial photosensitizers into natural protein cavities and the iterative mutagenesis in cell lysates. Through rounds of directed evolution, prominent visible-light-activatable photoenzyme variants were developed, featuring a thioxanthone chromophore. They successfully enabled the enantioselective [2 + 2] photocycloaddition of 2-carboxamide indoles, a class of UV-sensitive substrates that are traditionally challenging for known photoenzymes. Furthermore, the versatility of this photoenzyme is demonstrated in enantioselective whole-cell photobiocatalysis, enabling the efficient synthesis of enantioenriched cyclobutane-fused indoline tetracycles. These findings significantly expand the photophysical properties of artificial photoenzymes, a critical factor in enhancing their potential for harnessing excited-state reactivity in stereoselective transformations.
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Reação de Cicloadição , Estereoisomerismo , Indóis/química , Indóis/síntese química , Indóis/metabolismo , Processos Fotoquímicos , Biocatálise , Evolução Molecular Direcionada , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/síntese química , Luz , Escherichia coli/enzimologia , Estrutura MolecularRESUMO
Bullying victimization is widely accepted to be associated with aggression. However, the mechanisms underlying this relationship remain unknown. To examine the long-term impact of bullying victimization on aggression, the present study tested the potential mediating effects of both anger rumination and hostile automatic thoughts. A total of 809 undergraduates from four universities across China (74.80% female; Mage = 19.63 years, SD = 0.82 years) completed the survey on three occasions, with a 6-month delay between Time 1 and Time 2 and a 1-year interval between Time 2 and Time 3. A cross-lagged model of anger rumination and hostile automatic thoughts was developed to test whether they predicted one another, and two structural models were constructed to test their mediating roles in bullying victimization and aggression. Findings indicated that anger rumination and hostile automatic thoughts are mutually predictable; the correlation between bullying victimization and aggression is mediated independently by anger rumination and hostile automatic thoughts, and the chain mediation of bullying victimization predicting aggression first through anger rumination and then through hostile automatic thinking was established. In addition, an alternative mediation model is also significant, with hostile automatic thoughts as the primary mediator and anger rumination as the secondary mediator. These results highlight the significance of anger rumination and hostile automatic thoughts in the long-term effects of bullying victimization on aggression. Interventions designed to reduce undergraduate students' anger rumination and hostile automatic thoughts may help reduce their aggression.
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Baccaurea ramiflora Lour., an evergreen tree of the Baccaurea genus of the Phyllanthaceae family, is primarily distributed in South Asia, Southeast Asia, and southern China, including southern Yunnan Province. It is a wild or semi-cultivated tree species with ornamental, edible, and medicinal value, exhibiting significant development potential. In this study, we present the whole-genome sequencing of B. ramiflora, employing a combination of PacBio SMRT and Illumina HiSeq 2500 sequencing techniques. The assembled genome size was 975.8 Mb, with a contig N50 of 509.33 kb and the longest contig measuring 7.74 Mb. The genome comprises approximately 73.47% highly repetitive sequences, of which 52.1% are long terminal repeat-retrotransposon sequences. A total of 29,172 protein-coding genes were predicted, of which 25,980 (89.06%) have been annotated, Additionally, 3452 non-coding RNAs were identified. Comparative genomic analysis revealed a close relationship between B. ramiflora and the Euphorbiaceae family, with both being sister groups that diverged approximately 59.9 million years ago. During the evolutionary process, B. ramiflora exhibited positive selection in 278 candidate genes. Synonymous substitution rate and collinearity analysis demonstrated that B. ramiflora underwent a single ancient genome-wide triploidization event, without recent genome-wide duplication events. This high-quality B. ramiflora genome provides a valuable resource for basic research and tree improvement programs focusing on the Phyllanthaceae family.
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Genoma de Planta , Malpighiales , China , Sequências Repetitivas de Ácido Nucleico , Evolução Molecular , FilogeniaRESUMO
Small molecules with conformationally rigid, three-dimensional geometry are highly desirable in drug development, toward which a direct, simple-to-complexity synthetic logic is still of considerable challenges. Here, we report intermolecular aza-[2 + 2] photocycloaddition (the aza-Paternò-Büchi reaction) of indole that facilely assembles planar building blocks into ladder-shape azetidine-fused indoline pentacycles with contiguous quaternary carbons, divergent head-to-head/head-to-tail regioselectivity, and absolute exo stereoselectivity. These products exhibit marked three-dimensionality, many of which possess 3D score values distributed in the highest 0.5% region with reference to structures from DrugBank database. Mechanistic studies elucidated the origin of the observed regio- and stereoselectivities, which arise from distortion-controlled C-N coupling scenarios. This study expands the synthetic repertoire of energy transfer catalysis for accessing structurally intriguing architectures with high molecular complexity and underexplored topological chemical space.
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Different aromatic components do indeed give different tea flavors. There is still little research on whether there is a certain regularity in the combination and content of aromatic components in different aroma types of Phoenix Dancong (PDC) tea. This potential regularity may be a key factor in unraveling the relationship between reproduction and evolution in PDC tea. Here, the 5 kinds of these 4 aroma types PDC tea (Zhuye, Tuofu, Jianghuaxiang, Juduo, Yashixiang) were used as research materials in this study, the headspace solid-phase microextraction combined with gas chromatography-mass spectrometry was used to analyze the aromatic components of these PDC teas. The results showed a total of 36 aromatic components identified in this study. When conducting cluster analysis, it was found that similarity degree arrangement sequence of 5 PDC teas was Juduo, Tuofu, Yashixiang, Zhuye and Jianghuaxiang. Among these aromatic components, the 7,9-Di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione, the 2-Cyclopenten-1-one, 3-methyl-2-(2-pentenyl)-,(Z)-, the 2,4-Di-tert-butylphenol, the 3,7-dimethyl-1,5,7-Octatrien-3-ol, and the 2-Furanmethanol,5-ethenyltetrahydro-.alpha.,.alpha.,5-trimethyl-,cis- are common to 5 PDC teas. This study aims to elucidate the similarities in the aromatic components of 5 PDC teas, revealing the major aroma-endowed substances of various aroma, and providing theoretical reference for further exploring the relationship between aroma type discrimination, variety selection, and evolution of PDC teas.
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Odorantes , Compostos Orgânicos Voláteis , Odorantes/análise , Chá/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Análise por Conglomerados , Compostos Orgânicos Voláteis/análiseRESUMO
Dielectric elastomers (DEs) are widely used in soft actuation and sensing. Current DE actuators require high driving electrical fields because of their low permittivity. Most of DE actuators and sensors suffer from high viscoelastic effects, leading to high mechanical loss and large shifts of signals. This study demonstrates a valuable strategy to produce polyvinyl chloride (PVC)-based elastomers with high permittivity and low viscoelasticity. The introduction of cyanoethyl cellulose (CEC) into plasticized PVC gel (PVCg) not only confers a high dielectric permittivity (18.9@1 kHz) but also significantly mitigates their viscoelastic effects with a low mechanical loss (0.04@1 Hz). The CEC/PVCg actuators demonstrate higher actuation performances over the existing DE actuators under low electrical fields and show marginal displacement shifts (7.78%) compared to VHB 4910 (136.09%). The CEC/PVCg sensors display high sensitivity, fast response, and limited signal drifts, enabling their faithful monitoring of multiple human motions.
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'Candidatus Liberibacter asiaticus' is the bacterium associated with the citrus disease known as huanglongbing (HLB). This study evaluated the influence of 'Ca. L. asiaticus' infection on a number of key plant physiological variables concerning photosynthesis, cell integrity, reactive oxygen species scavengers' activity, and osmoregulation of two different species of citrus-the pomelo Citrus maxima and the mandarin C. reticulata 'Tankan'-relative to their measured 'Ca. L. asiaticus' infection load. Results indicated that all measured physiological variables except soluble sugar were affected by increased 'Ca. L. asiaticus' infection titers, wherein the variety C. maxima proved overall more resistant than C. reticulata. 'Ca. L. asiaticus' infection was linked in both plants to decrease in chlorophyll concentration, cell membrane permeability, and malondialdehyde, as well as increased free proline and starch contents. Chlorophyll fluorescence measurements taken 9 months after grafting the mandarin C. reticulata with 'Ca. L. asiaticus' scions revealed a significant decrease in the photosynthesis variables maximum photochemical quantum yield of photosystem II (PSII), effective photochemical quantum yield of PSII, and coefficient of photochemical fluorescence quenching assuming interconnected PSII antennae, whereas nonphotochemical fluorescence quenching increased significantly; C. maxima plants, on the other hand, did not show significant differences until the 12th month from infection exposure. The variables superoxide dismutase, catalase, peroxidase, and soluble protein initially increased and later decreased. In addition, progression of 'Ca. L. asiaticus' replication in both citrus species was accompanied by rapid changes in three reactive oxygen species scavenging enzymes in C. maxima, while the pattern was different in C. reticulata. We hypothesize that the observed interspecific differences in physiological change are related to their relative resistance against 'Ca. L. asiaticus' infection. These results provide a scaffold for better describing the pathogenesis, selecting the most resistant breeds, or even validating pertaining omics research; ultimately, these detailed observations can facilitate the diagnosis of 'Ca. L. asiaticus' infection.
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Citrus , Rhizobiaceae , Citrus/microbiologia , Liberibacter , Rhizobiaceae/fisiologia , Espécies Reativas de Oxigênio , Doenças das Plantas/microbiologia , Melhoramento Vegetal , ClorofilaRESUMO
Camellia chekiangoleosa is a popular variety of Oil-camellia that has high oil production and ornamental value. Microsatellite (SSR) markers are the preferred tool for the molecular marker-assisted breeding of C. chekiangoleosa. By focusing on the problems of the low development efficiency of polymorphic SSR markers and the lack of available functional markers in Oil-camellia, we identified 97,510 SSR loci based on the full-length transcriptome sequence of C. chekiangoleosa. An analysis of SSR characteristics showed that mononucleotide (51.29%) and dinucleotide (34.36%) SSRs were the main repeat types. The main SSR distribution areas based on proportion covered were ordered as follows: 5'UTR > 3'UTR > CDS. By comparing our data with those in databases such as GO and KEGG, we obtained functional annotations of unigene sequences containing SSR sites. The data showed that the amplification efficiency of the SSR primers was 51.72%, and the development efficiency of polymorphic SSR primers was 26.72%. Experiments verified that dinucleotide and pentanucleotide SSRs located in UTR regions could produce more polymorphic markers. An investigation into the genetic diversity of several C. chekiangoleosa populations also suggested that the developed SSR markers had higher levels of polymorphism. This study will provide a reference and high-quality markers for the large-scale development of functional SSR markers and genetic research in Oil-camellia.
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Camellia , Camellia/genética , Transcriptoma/genética , Melhoramento Vegetal , Repetições de Microssatélites/genética , Polimorfismo Genético , Etiquetas de Sequências ExpressasRESUMO
Naturally evolved enzymes, despite their astonishingly large variety and functional diversity, operate predominantly through thermochemical activation. Integrating prominent photocatalysis modes into proteins, such as triplet energy transfer, could create artificial photoenzymes that expand the scope of natural biocatalysis1-3. Here, we exploit genetically reprogrammed, chemically evolved photoenzymes embedded with a synthetic triplet photosensitizer that are capable of excited-state enantio-induction4-6. Structural optimization through four rounds of directed evolution afforded proficient variants for the enantioselective intramolecular [2+2]-photocycloaddition of indole derivatives with good substrate generality and excellent enantioselectivities (up to 99% enantiomeric excess). A crystal structure of the photoenzyme-substrate complex elucidated the non-covalent interactions that mediate the reaction stereochemistry. This study expands the energy transfer reactivity7-10 of artificial triplet photoenzymes in a supramolecular protein cavity and unlocks an integrated approach to valuable enantioselective photochemical synthesis that is not accessible with either the synthetic or the biological world alone.
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Biocatálise , Reação de Cicloadição , Enzimas , Processos Fotoquímicos , Biocatálise/efeitos da radiação , Transferência de Energia , Estereoisomerismo , Enzimas/genética , Enzimas/metabolismo , Enzimas/efeitos da radiação , Indóis/química , Especificidade por Substrato , Cristalização , Evolução Molecular Direcionada/métodosRESUMO
We report the molecular design of a novel multifunctional reagent and its application for light-controlled selective protein labeling. This molecule integrates functions of protein-ligand recognition, bioconjugation, ligand cleavage, and photoactivation by merging the photochemistries of 2-nitrophenylpropyloxycarbonyl and 3-hydroxymethyl-2-naphthol with an affinity ligand and fluorescein. Highly electrophilic o-naphthoquinone methide was photochemically released and underwent proximity-driven selective labeling with the protein of interest (e.g., carbonic anhydrases), which retains its native function after labeling.
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Anidrases Carbônicas , Membro 14 da Superfamília de Ligantes de Fatores de Necrose Tumoral , Fluoresceínas , Ligantes , Naftoquinonas , Proteínas/químicaRESUMO
BACKGROUND: Three-dimensional fluid-attenuated inversion-recovery (3 D-FLAIR) and real inversion-recovery (3 D-real IR) sequences are used to detect endolymphatic hydrops (EH), but medium inversion-time inversion-recovery imaging with magnitude reconstruction (MIIRMR) may be more sensitive. AIMS: We investigated the inner-ear visualisation success rate and EH detection rates of 3 D-FLAIR and 3 D-real IR, and whether salvage MIIRMR could improve EH detection. MATERIALS AND METHODS: Fifty-one patients (102 ears) with episodic or chronic vestibular syndrome were injected intra-tympanically with 8-fold diluted gadolinium, and 3 D-FLAIR and 3 D-real IR images obtained 24-h post-injection. If 3 D-FLAIR inner-ear visualisation failed, additional MIIRMR was performed. The success and EH detection rate increase by MIIRMR was calculated. The diagnostic performance of combined MIIRMR + 3D-FLAIR + 3D-real IR for Meniere's disease (MD) was evaluated. RESULTS: The success rates of 3 D-FLAIR and 3 D-real IR were 88.90% and 72.55%, respectively. MIIRMR increased the success and EH detection rates by 11.10% and 6.86%, respectively. In MD, MIIRMR increased these rates by 10.53% and 10.53%, respectively. 3 D-FLAIR + 3D-real IR + MIIRMR had 92.11% sensitivity, 79.68% specificity, 72.92% positive-predictive value, and 94.44% negative-predictive value for MD diagnosis. CONCLUSION AND SIGNIFICANCE: MIIRMR can improve success and EH detection rates when 3 D-FLAIR fails. Combined MIIRMR + 3D-FLAIR + 3D-real IR is more valuable for diagnosing MD than conventional sequences.
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Hidropisia Endolinfática , Doença de Meniere , Meios de Contraste , Hidropisia Endolinfática/diagnóstico por imagem , Gadolínio , Gadolínio DTPA , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética/métodos , Doença de Meniere/diagnóstico por imagemRESUMO
In this paper, we report an efficient approach for the direct fluoroalkylthiolation of indoles with iodofluoroethane in the presence of Na2S2O4. In this work, we employed readily available iodofluoroethane and Na2S2O4 as fluoroalkylthiolation reagents, featuring mild conditions and a wide range of indole substrates. In addition, fluoroalkylthiolated 2,3'-biindole derivatives can also be prepared by this method.
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Cochlear implant, as the most successful artificial auditory implant, brings tens of thousands of patients with severe or profound sensorineural hearing loss back to the world of sound every year. With the expansion of surgical indications, a large number of difficult cases bring new challenges for cochlear implantation. As a new technology, cone beam CT has the double advantages of high spatial resolution and low radiation. It is considered as the second revolution of CT technology, which shows unique value in the application of cochlear implantation. This article reviews the basic principles of cone beam CT and its application and research progress in cochlear implantation.
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Implante Coclear , Implantes Cocleares , Perda Auditiva Neurossensorial , Tomografia Computadorizada de Feixe Cônico , Perda Auditiva Neurossensorial/diagnóstico por imagem , Perda Auditiva Neurossensorial/cirurgia , Humanos , Osso Temporal/cirurgiaRESUMO
Elevated extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinase-9 (MMP-9) in oxidized low density lipoprotein (oxLDL)-induced macrophages leads to the progression of vulnerable plaques by degradation of the extracellular matrix. Our previous report showed that berberine regulates the expression of both EMMPRIN and MMP-9. In addition, P2X7 receptor (P2X7R) upregulation plays a crucial role in the development of atherosclerosis. However, it is unclear whether berberine regulated P2X7R level to inhibit both EMMPRIN and MMP-9 expession in macrophages. In the present study, we investigated the impact of berberine on P2X7R expression and the regulation of P2X7R in the expression of EMMPRIN and MMP-9 in oxLDL-induced macrophages. We found that P2X7R expression was increased, miR150-5p was reduced in oxLDL-induced macrophages, relatively. And A-438079 (a P2X7R inhibitor) or miR150-5p mimic treatment greatly reversed the upregulation of EMMPRIN and MMP-9 expression. Moreover, A-438079 significantly reduced oxLDL-induced AMP-activated protein kinase-α (AMPK-α) phosphorylation and reversed the activation of mitogen-activated protein kinase (MAPK), which in turn decreased the expression of EMMPRIN and MMP-9. These findings illustrate that P2X7R suppresses EMMPRIN and MMP-9 expression by inhibiting the AMPK-α/MAPK pathway in oxLDL-induced macrophages. Accordingly, exposure to berberine markedly upregulated miR150-5p, decreased P2X7R expression and downregulated MMP-9 and EMMPRIN levels in oxLDL-induced macrophages, resulting in AMPK-α/MAPK (JNK, p38, and ERK) inactivation. Overall, these results indicate that berberine increased miR150-5p level, subsequently inhibits P2X7R-mediated EMMPRIN and MMP-9 expression by suppressing AMPK-α and MAPK signaling in oxLDL-induced macrophages.
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Vinclozolin is a common dicarboximide fungicide used to protect crops from diseases. It is also an endocrine disruptor and is thought to be related to abnormalities of the reproductive tract. However, its mechanism of inducing abnormalities of the male reproductive tract is still unclear. The purpose of this study was to study the effect of gestational vinclozolin exposure on the development of rat fetal Leydig cells. Female pregnant Sprague-Dawley rats were exposed to vinclozolin (0, 25, 50, and 100 mg/kg body weight/day) by gavage from gestational day 14-21. Vinclozolin dose-dependently reduced serum testosterone levels at doses of 50 and 100 mg/kg and the anogenital distance at 100 mg/kg. RNA-seq, qPCR, and Western blotting showed that vinclozolin down-regulated the expression of Nr5a1, Sox9, Lhcgr, Cyp11a1, Hsd3b1, Hsd17b3, Amh, Pdgfa, and Dhh and their encoded proteins. Vinclozolin reduced the number of NR2F2-positive stem Leydig cells at a dose of 100 mg/kg and enhanced autophagy in the testes. In conclusion, vinclozolin disrupts reproductive tract development and testis development in male fetal rats via several pathways.
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Disruptores Endócrinos/toxicidade , Fungicidas Industriais/toxicidade , Organogênese/efeitos dos fármacos , Oxazóis/toxicidade , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Testículo/efeitos dos fármacos , Animais , Autofagia/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Células Intersticiais do Testículo/efeitos dos fármacos , Células Intersticiais do Testículo/metabolismo , Células Intersticiais do Testículo/patologia , Masculino , Gravidez , Ratos , Ratos Sprague-Dawley , Testículo/embriologia , Testículo/patologia , Testosterona/sangueRESUMO
SCOPE: Shellfish allergy is an important cause of food allergy, and tropomyosin (TM) is the major allergen within shellfish. Probiotics are safe bacteria that benefit host health and nutrition and is proposed as a novel approach for treating immunological diseases, including food allergies. METHODS AND RESULTS: The probiotic strain Lactobacillus casei Zhang (LcZ) isolated from koumiss is investigated for its capacity to modulate food allergy induced by TM in BALB/c mice. Oral administration of LcZ attenuated allergy symptoms and intestinal epithelial damage. Furthermore, flow cytometry, real-time quantitative PCR, and ELISA demonstrated that LcZ administration altered the development and function of dendritic cells (DCs), T cells, and B cells, finally resulting in the change of TM-specific antibody isotypes into a tolerogenic pattern. Moreover, an in vitro spleen cell culture model reveals that LcZ directly modulates regulatory tolerogenic DC and T cell development, dependent on the activation of the nuclear factor kappa B (NF-κB) signaling pathway. CONCLUSION: This work indicates the ability of LcZ to alleviate TM-induced food allergy and demonstrates the involvement of the tolerogenic immune cells and NF-κB signaling pathway, indicating LcZ to be a potential immunomodulator and immunotherapy assistor.
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Lacticaseibacillus casei , Probióticos/farmacologia , Hipersensibilidade a Frutos do Mar/tratamento farmacológico , Tropomiosina/toxicidade , Administração Oral , Proteínas Animais da Dieta/imunologia , Proteínas Animais da Dieta/toxicidade , Animais , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Células Cultivadas , Feminino , Tolerância Imunológica , Linfonodos/efeitos dos fármacos , Linfonodos/imunologia , Camundongos Endogâmicos BALB C , NF-kappa B/metabolismo , Penaeidae/química , Probióticos/administração & dosagem , Hipersensibilidade a Frutos do Mar/etiologia , Hipersensibilidade a Frutos do Mar/imunologia , Baço/efeitos dos fármacos , Baço/imunologia , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Tropomiosina/imunologiaRESUMO
Porphyra polysaccharides possess multiple pharmacological activities, such as immunoregulatory, anti-tumor and anti-inflammatory effects, but the specific underlying mechanisms are not fully understood. The present work was to investigate the immunomodulatory activity of two different Porphyra polysaccharides, PH and PY, in a BALB/c mouse model and a mouse splenic cell model. Results showed that PH and PY regulated Th1 and Th2 responses, which could be due to the proliferation of CD4+CD25+ Treg. Further investigations demonstrated that PY induced the proliferation and maturation of upstream MHC II+CD11c+ DC. Moreover, both PH and PY activate NF-κB signaling pathways in splenic cells, but the loss-of-function assay with a NF-κB inhibitor demonstrated that the direct Treg-induction activity of PH, but not PY, was mediated by NF-κB. These results suggested that PH and PY show strong immunomodulatory activity by NF-κB-dependent immunocyte maturation and differentiation, which facilitates further application of Porphyra polysaccharides as potential functional foods or immunomodulators.
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Diferenciação Celular/efeitos dos fármacos , Células Dendríticas/efeitos dos fármacos , NF-kappa B/imunologia , Extratos Vegetais/farmacologia , Polissacarídeos/farmacologia , Porphyra/química , Baço/citologia , Linfócitos T Reguladores/efeitos dos fármacos , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Células Dendríticas/citologia , Células Dendríticas/imunologia , Homeostase/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , NF-kappa B/genética , Extratos Vegetais/química , Polissacarídeos/química , Baço/efeitos dos fármacos , Baço/imunologia , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologiaRESUMO
This study presents a novel and facile strategy to fabricate a hydrophilic poly(vinylidene fluoride) (PVDF) electrolyte film with enhanced inner channels for a high-performance and cost-effective ion-exchange polymer metal composite (IPMC) actuator. The resultant PVDF composite film is composed of hierarchical micro/nanoscale structures: well-defined polymer grains with a diameter of â¼20 µm and much finer particles with a diameter of â¼390 nm, producing three-dimensional interconnected, hierarchical inner channels to facilitate ion migration of IPMC. Interestingly, the electrolyte matrix film has a high porosity of 15.8% and yields a high water uptake of 44.2% and an ionic liquid (IL, [EMIm]·[BF4]) uptake of 38.1% to make both water-driven and IL-driven IPMC actuators because of the introduction of polar polyvinyl pyrrolidone. Compared to the conventional PVDF/IL-based IPMC, both water-driven and IL-driven PVDF-based IPMCs exhibit high ion migration rates, thus effectively improving the actuation frequency and producing remarkably higher levels of actuation force and displacement. Specifically, the force outputs are increased by 13.4 and 3.0 folds, and the displacement outputs are increased by 2.2 and 1.9 folds. Using an identical electrolyte matrix, water-driven IPMC exhibits stronger electromechanical performance, benefiting to make IPMC actuator with high levels of force and power outputs, whereas IL-driven IPMC exhibits a more stable electromechanical performance, benefiting to make long lifetime IPMC actuator in air. Thus, the resultant IPMCs are promising in the design of artificial muscles with tunable electromechanical performance for flexible actuators or displacement/vibration sensors at low cost.
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Comparing with the precious metal catalysts, non-precious metal catalysts were preferred to use in microbial fuel cells (MFCs) due to the low cost and high oxygen reduction reaction (ORR) efficiency. In this study, the transmission electron microscope and X-ray diffraction as well as Raman investigation revealed that the prepared nanoscale NiO was attached on the surface of CNT. Cyclic voltammogram and rotating ring-disk electrode tests showed that the NiO/CNT composite catalyst had an apparent oxygen reduction peak and 3.5 electron transfer pathway was acquired under oxygen atmosphere. The catalyst performance was highly dependent on the percentage of NiO in the CNT nanocomposites. When 77% NiO/CNT nano-sized composite was applied as cathode catalyst in membrane free single-chamber air cathode MFC, a maximum power density of 670 mW/m(2) and 0.772 V of OCV was obtained. Moreover, the MFC with pure NiO (control) could not achieve more than 0.1 V. All findings suggested that NiO/CNT could be a potential cathode catalyst for ORR in MFCs.