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1.
Am J Hypertens ; 2024 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-38761040

RESUMO

BACKGROUND: Hypertension is a risk factor for atrial fibrillation (AF), and brain and muscle arnt-like protein 1 (Bmal1) regulate circadian blood pressure and is implicated in several fibrotic disorders. Our hypothesis that Bmal1 inhibits atrial fibrosis and susceptibility to AF in salt-sensitive hypertension (SSHT) and our study provide a new target for the pathogenesis of AF induced by hypertension. METHODS: The study involved 7-week-old male Dahl salt-sensitive that were fed either a high-salt diet (8% NaCl; DSH group) or a normal diet (0.3% NaCl; DSN group). An experimental model was used to measure systolic blood pressure (SBP), left atrial ejection fraction (LAEF), left atrial end-volume index (LAEVI), left atrial index (LAFI), AF inducibility, AF duration, and atrial fibrosis pathological examination and the expression of Baml1 and fibrosis-related proteins (TNF-α and α-SMA) in left atrial tissue. RESULTS: DSH increased TNF-α and α-SMA expression in atrial tissue, level of SBP and LAESVI, atrial fibrosis, AF induction rate and AF duration, and decreased Bmal1 expression in atrial tissue, circadian rhythm of hypertension and level of LAEF and LAFI. Our results also showed that the degree of atrial fibrosis was negatively correlated with Bmal1 expression, but positively correlated with the expression of TNF-α and α-SMA. CONCLUSIONS: We demonstrated that a high-salt diet leads to circadian changes in hypertension due to reduction Bmal1 expression, which plays a crucial role in atrial fibrosis and increased susceptibility to AF in SSHT rats.

2.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1867(12): 159221, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35981705

RESUMO

Polo-like kinase 1 (PLK1) is a serine/threonine kinase involving lipid metabolism and cardiovascular disease. However, its role in atherogenesis has yet to be determined. The aim of this study was to observe the impact of PLK1 on macrophage lipid accumulation and atherosclerosis development and to explore the underlying mechanisms. We found a significant reduction of PLK1 expression in lipid-loaded macrophages and atherosclerosis model mice. Lentivirus-mediated overexpression of PLK1 promoted cholesterol efflux and inhibited lipid accumulation in THP-1 macrophage-derived foam cells. Mechanistic analysis revealed that PLK1 stimulated the phosphorylation of AMP-activated protein kinase (AMPK), leading to activation of the peroxisome proliferator-activated receptor γ (PPARγ)/liver X receptor α (LXRα) pathway and up-regulation of ATP binding cassette transporter A1 (ABCA1) and ABCG1 expression. Injection of lentiviral vector expressing PLK1 increased reverse cholesterol transport, improved plasma lipid profiles and decreased atherosclerotic lesion area in apoE-deficient mice fed a Western diet. PLK1 overexpression also facilitated AMPK and HSL phosphorylation and enhanced the expression of PPARγ, LXRα, ABCA1, ABCG1 and LPL in the aorta. In summary, these data suggest that PLK1 inhibits macrophage lipid accumulation and mitigates atherosclerosis by promoting ABCA1- and ABCG1-dependent cholesterol efflux via the AMPK/PPARγ/LXRα pathway.


Assuntos
Aterosclerose , Proteínas de Ciclo Celular , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Animais , Apolipoproteínas E/metabolismo , Aterosclerose/metabolismo , Proteínas de Ciclo Celular/genética , Colesterol/metabolismo , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Camundongos , PPAR gama/genética , PPAR gama/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Serina , Quinase 1 Polo-Like
3.
Front Pharmacol ; 12: 690371, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34950023

RESUMO

Atrial fibrosis is the basis for the occurrence and development of atrial fibrillation (AF) and is closely related to the Warburg effect, endoplasmic reticulum stress (ERS) and mitochondrion dysfunctions-induced cardiomyocyte apoptosis. Hydrogen sulfide (H2S) is a gaseous signalling molecule with cardioprotective, anti-myocardial fibrosis and improved energy metabolism effects. Nevertheless, the specific mechanism by which H2S improves the progression of atrial fibrosis to AF remains unclear. A case-control study of patients with and without AF was designed to assess changes in H2S, the Warburg effect, and ERS in AF. The results showed that AF can significantly reduce cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate thiotransferase (3-MST) expression and the H2S level, induce cystathionine-ß-synthase (CBS) expression; increase the Warburg effect, ERS and atrial fibrosis; and promote left atrial dysfunction. In addition, AngII-treated SD rats had an increased Warburg effect and ERS levels and enhanced atrial fibrosis progression to AF compared to wild-type SD rats, and these conditions were reversed by sodium hydrosulfide (NaHS), dichloroacetic acid (DCA) or 4-phenylbutyric acid (4-PBA) supplementation. Finally, low CSE levels in AngII-induced HL-1 cells were concentration- and time-dependent and associated with mitochondrial dysfunction, apoptosis, the Warburg effect and ERS, and these effects were reversed by NaHS, DCA or 4-PBA supplementation. Our research indicates that H2S can regulate the AngII-induced Warburg effect and ERS and might be a potential therapeutic drug to inhibit atrial fibrosis progression to AF.

4.
Environ Technol ; 36(13-16): 1847-54, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25650667

RESUMO

4-Chloronitrobenzene (4-CNB) is one of the highly toxic contaminants that may lead to acute, chronic or persistent physiological toxicity to ecology and environment. Conventional methods for removing 4-CNB from aquatic environment may be problematic due to inefficiency, high cost and low sustainability. This study develops a pilot-scale bioelectrochemical system (BES, effective volume of 18 L) and examines its performance of bioelectrochemical transformation of 4-CNB to 4-chloroaniline (4-CAN) under continuous operation. The results demonstrate that the initial 4-CNB concentration in the influent and hydraulic retention time (HRT) has a significant impact on 4-CNB reduction and 4-CAN formation. Compared with the conventional anaerobic process in the absence of external power supplied, the 4-CNB conversion efficiency can be enhanced with power supplied due to microbial-mediated electron transfer at the negative cathode potential. At a voltage of 0.4 V and HRT of 48 h, the 4-CNB reduction and 4-CAN formation efficiency reached 99% and 94.1%, respectively. Based on a small external voltage applied, the pilot-scale BES is effective in the conversion of 4-CNB to 4-CAN, an intermediate that is of less toxicity and higher bioavailability for subsequent treatment. This study provides a new strategy and methods for eliminating 4-CNB, making wastewater treatment more economical and more sustainable.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Eletroquímica/instrumentação , Nitrobenzenos/isolamento & purificação , Nitrobenzenos/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/instrumentação , Reatores Biológicos/microbiologia , Eletroquímica/métodos , Eletrodos , Eletrólise/instrumentação , Eletrólise/métodos , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Projetos Piloto , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos
5.
Biosens Bioelectron ; 58: 272-5, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24657648

RESUMO

In this study, ethylenediamine tetraacetic acid (EDTA) was investigated as a new kind of non-polymeric catalyst binder to improve interfacial oxygen reduction reaction (ORR) for the cathode of microbial fuel cell (MFC). The electrochemical analysis and MFC tests show negative correlation between ORR activity and molar concentration of EDTA applied during electrode preparation. In particular, the 0.02mol/L-EDTA yields higher ORR activity than other binder materials like Nafion, water, 0.1mol/L-EDTA and 0.2mol/L-EDTA, as indicated by the strongest response of ORR current and the smallest charge-transfer resistance. Accordingly, the MFC with cathode of 0.02mol/L-EDTA produced a maximum power density of 722mW/m(2), accounting for a value approximately 42% higher than that of commercial Nafion binder (5wt%, 507mW/m(2)). The improved ORR activity should be attributed to the enhanced proton transfer from phosphate ions to EDTA-involved three-phase boundary as a result of dipole ion bonds on nitrogen atoms having unshared pair of electrons in EDTA molecule.


Assuntos
Fontes de Energia Bioelétrica , Ácido Edético/química , Eletrodos , Oxigênio/química , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Oxirredução , Propriedades de Superfície
6.
Biosens Bioelectron ; 55: 237-41, 2014 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-24384266

RESUMO

To explore efficient and cost-effective cathode material for microbial fuel cells (MFCs), the present study fabricates a new type of binder-free gas diffusion electrode made of cobalt oxide (Co3O4) micro-particles directly grown on stainless steel mesh (SSM) by using an ammonia-evaporation-induced method. In various electrochemical analyses and evaluations in batch-fed dual-chamber MFCs, the SSM/Co3O4 hybrid electrode demonstrates improved performances in terms of electrocatalytic activity, selectivity, durability and economics toward oxygen reduction reaction (ORR) in pH-neutral solution, in comparison with conventional carbon supported platinum catalyst. This study suggests a new strategy to fabricate a more effective electrode for ORR in MFCs, making it more technically and economically viable to produce electrical energy from organic materials for practical applications.


Assuntos
Bactérias Aeróbias/fisiologia , Fontes de Energia Bioelétrica/microbiologia , Cobalto/química , Eletrodos , Transferência de Energia/fisiologia , Óxidos/química , Oxigênio/metabolismo , Aço Inoxidável/química , Catálise , Desenho de Equipamento , Análise de Falha de Equipamento , Oxirredução
7.
Biosens Bioelectron ; 26(5): 2142-6, 2011 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20947329

RESUMO

This study reports the fabrication of a new membrane electrode assembly by using stainless steel mesh (SSM) as raw material and its effectiveness as gas diffusion electrode (GDE) for electrochemical oxygen reduction in microbial fuel cell (MFC). Based on feeding glucose (0.5 g L(-1)) substrate to a single-chambered MFC, power generation using SSM-based GDE was increased with the decrease of polytetrafluoroethylene (PTFE) content applied during fabrication, reaching the optimum power density of 951.6 mW m(-2) at 20% PTFE. Repeatable cell voltage of 0.51 V (external resistance of 400 Ω) and maximum power density of 951.6 mW m(-2) produced for the MFC with SSM-based GDE are comparable to that of 0.52 V and 972.6 mW m(-2), respectively obtained for the MFC containing typical carbon cloth (CC)-made GDE. Besides, Coulombic efficiency (CE) is found higher for GDE (SSM or CC) with membrane assembly than without, which results preliminarily from the mitigation of Coulombic loss being associated with oxygen diffusion and substrate crossover. This study demonstrates that with its good electrical conductivity and much lower cost, the SSM-made GDE suggests a promising alternative as efficient and more economically viable material to conventional typical carbon for power production from biomass in MFC.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Fontes de Energia Elétrica/microbiologia , Eletrodos/microbiologia , Aço Inoxidável/química , Difusão , Desenho de Equipamento , Análise de Falha de Equipamento , Gases/química
8.
Bioresour Technol ; 101(15): 6265-8, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20363119

RESUMO

This study investigated the temperature influence on intracellular absorption and extra-cellular phosphorus removal by extra-cellular polymeric substance (EPS) in enhanced biological phosphorus removal (EBPR) process. Three sequencing batch reactors (SBRs) were operated in anaerobic/aerobic sequence at 5.0, 15.0 and 25.0 degrees C. Phosphorus removed by intracellular absorption was demonstrated as the dominant part (>80%) in total phosphorus removal operated under different temperatures and the highest total phosphorus removal rate of 95% was obtained due to the highest intracellular phosphorus absorption of 18.2mg P in a typical cycle at 15.0 degrees C. Phosphorus removed by EPS removal achieved the highest value at 5.0 degrees C (2.4 mg P/cycle), which resulted in a higher total phosphorus removal rate at 5.0 degrees C (90%) than that at 25.0 degrees C (83%). Low temperature was propitious to EPS phosphorus removal, accounting for 13% of total phosphorus removal at 5.0 degrees C, which could be mainly due to magnesium phosphate precipitation.


Assuntos
Reatores Biológicos/microbiologia , Fósforo/isolamento & purificação , Fósforo/metabolismo , Esgotos/microbiologia , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Temperatura Alta , Fósforo/química , Poluentes Químicos da Água/isolamento & purificação
10.
Huan Jing Ke Xue ; 30(1): 80-4, 2009 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-19353861

RESUMO

Enhanced biological phosphorus removal (EBPR) process was operated in a laboratory-scale sequencing batch reactor (SBR) for one-month fed with acetate as the carbon source. The characteristic and the microbial population structure and space distribution dynamics of phosphate-accumulating organisms (PAOs) of start-up period were analyzed by fluorescent in situ hybridization (FISH). The relationship between enrichment of PAOs and phosphorus removal was discussed. PAOs could be enriched by recirculation activated sludge containing heterotrophs through anaerobic aerobic conditions. Portion of PAOs in the sludge increase from 11.5% to 40.48%. Bacteria population competition lasted 34 days. It started from PAOs replacing heterotrophs which cost 5 days then followed by 19 days intra-specific competition of PAOs. The last step was re-increasing of PAOs predominance. Phosphorus uptake by the enriched microbial community was not observed immediately. An accumulating-phase was necessary for PHA and poly-P storage. A lag-stage of 4-8 days existed when taking the performance of the reactor into consideration. Phosphorus removal by the predominant PAOs through intra-specific competition was achieved after accumulating-phase too. The FISH picture indicated that in the quickly growing phase PAOs cells were small and community structure was loose. The latter "accumulating-phase" cells became larger and the community structure clustered densely. This stage presented by better reactor performance.


Assuntos
Reatores Biológicos/microbiologia , Fósforo/metabolismo , Proteobactérias/genética , Proteobactérias/fisiologia , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Biodegradação Ambiental , DNA Bacteriano/análise , Hibridização in Situ Fluorescente , Fósforo/isolamento & purificação , Proteobactérias/isolamento & purificação
11.
Huan Jing Ke Xue ; 30(1): 155-9, 2009 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-19353874

RESUMO

The performance and membrane fouling of submerged membrane bioreactor were studied in the case of active sludge bulking under low temperature. The factors contributing to membrane fouling were discussed from the microorganism aspect. The results showed that COD removal efficiencies of supernatant and permeate were 85% and 92% respectively and filamentous sludge bulking had little impact on them. The sludge settleability became bad and the filament index (FI) increased from 2 to 5 during the formation of filamentous sludge bulking under low temperature. The filamentous bacteria extending from the sludge flocs formed net structure. Membrane fouling changed with time in linear under low temperature and the operation period of MBR was 15 d. However, membrane fouling was more serious in the condition of filamentous sludge bulking at low temperature, shortening the operation period of MBR to 7 d. The extracellular polymeric substances (EPS) content of bulking sludge was three times as that of normal sludge and the relative hydrophobicity (RH) of sludge flocs was decreased as FI increased. The increase of EPS and RH may cause more materials to deposit on the membrane surface, thus the membrane fouling rate improved and the operation period of MBR became short. Further analysis indicated that the mixed liquid viscosity, Zeta potential and sludge floc structure were all important factors of membrane fouling.


Assuntos
Reatores Biológicos/microbiologia , Temperatura Baixa , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Análise de Falha de Equipamento , Membranas Artificiais
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