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1.
Heliyon ; 10(4): e26630, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38434019

RESUMO

Cigars have unique aroma and style characteristics. In order to clarify the differences of aroma components between domestic and imported cigars and the material basis of the stylistic characteristics of different cigars, gas chromatography-mass spectrometry (GC-MS) and sensory evaluation were used to compare and analyze the aroma components in the mainstream smoke of four domestic cigars and two imported cigars. The GC-MS results showed that a total of 97 aroma components were measured in the smoke of the six cigars, and the types of aroma components were similar, but there were differences in their contents. In comparison with those of domestic cigars, imported cigars had suitable nicotine content, and higher contents of phytol, neophytadiene, 3-methylpentanoic acid, and (+)-δ-cadinene. To further explore the differences in the aroma components of the six cigars, GC-MS data combined with chemometrics were used to screen out 14 key aroma components based on P-value (P) < 0.05, Variable Importance Projection (VIP) > 1, and Aroma Activity Values (OAV) > 1. The key aroma components of each cigar were obtained, Snow Dream No. 5: cedrol; Wangguan Guocui: 6-methyl-5-hepten-2-one, pyridine, 2-ethyl-6-methylpyrazine; General Achileus No. 3: p-cresol, 2-methylbutyraldehyde, methyl cyclopentenolone; Montecristo No. 4: cedrol, 2-methylbutyraldehyde, guaiacol, 4-vinylguaiacol, methyl cyclopentenolone; Romeo y Julieta Wide Churchills: cedrol, 2,6-dimethylpyrazine, 2-ethyl-6-methylpyrazine, 2-heptanone, phenethyl alcohol; Great Wall No. 2: p-cresol, phenethyl alcohol, geranylacetone, methyl cyclopentenolone, dihydroactinidiolide. The odor descriptors of these compounds were consistent with the aroma profiles that were prominent in the senses of each cigar. This experiment initially explored the differences in aroma composition and style characteristics of cigars and provided data to support the quality improvement of domestic cigars.

2.
Front Bioeng Biotechnol ; 11: 1201957, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37691904

RESUMO

Introduction: Candida genus plays a crucial role in cigar fermentation, and strains from different sources might have differences in metabolic characteristics. Therefore, this study conducted directional isolation of Candida strains from cigar tobacco leaves and compared their fermentabilities to screen suitable strains for cigar fermentation, thereby improving the cigar quality. Methods: First, the Candida strains from cigars tobacco leaves in different production areas were directionally isolated by pure culture. Then, the isolated strains were screened based on chemical indexes and flavor component contents. Finally, the fermentabilities of preferred strains were verified by sensory evaluation. Results: Five strains of C. parapsilosis and four strains of C. metapsilosis were obtained through directional isolation. By comparing the physicochemical indexes of nine strains of Candida, it was found that C. parapsilosis P1 and C. metapsilosis M4 not only reduced the alkaloids content (by 25.3% and 32.6%, respectively) but also increased the flavor components content (by 25.2% and 18.9%, respectively). Among them, P1 could raise the content of chlorophyll degradation products, carotenoid degradation products, and Maillard reaction products, and enhance the beany and nutty flavor of cigars. M4 could raise the content of chlorophyll degradation products, cembranoids degradation products, and Maillard reaction products, and improve the baking, nutty, cocoa, and honey flavor of the cigar. Discussion: In this study, the Candida strains were directionally isolated from cigars tobacco leaves in different production areas, and two functional strains suitable for cigar fermentation were screened based on physicochemical indexes and sensory evaluation, which would contribute to the directed regulation of cigar quality and flavor diversification.

3.
Bioresour Technol ; 376: 128917, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36934909

RESUMO

A novel electric field membrane bioreactor (EMBR) for mariculture wastewater treatment utilizing reduced graphene oxide/polypyrrole ceramic membrane (rGO/PPy CM) was constructed and compared with MBRs using CM support and rGO/PPy CM. EMBR (rGO/PPy) obtained the highest pollutant removal rates (84.99% for TOC, 85.98% for NH4+-N), the lowest average membrane fouling rate (2.42 kPa/d) and pollutant adhesion performance by characterization. Meanwhile, the specific fluxes of characteristic foulants in EMBR were enhanced, and the total resistances were reduced by 8.12% to 62.46%. The underlying mechanisms included reduced attraction energy and improved electrostatic repulsion between contaminants in EMBR and membrane by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, DLVO model and force analysis. Therefore, this study complemented the understanding of antifouling effect and mechanism in EMBR by interaction energy and force analysis of characteristic pollutants. These findings also provided new insights into the application of EMBR for mariculture wastewater treatment.


Assuntos
Polímeros , Purificação da Água , Pirróis , Membranas Artificiais , Reatores Biológicos
4.
Ultrason Sonochem ; 78: 105750, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34544014

RESUMO

The novel system, consisting of composite oxidants (persulfate/chlorite, S2O82-/ClO2-) and stationary phase activator (zero-valent-iron foam, Fe0f) driven by ultrasonic (US) field, was applied to treat the triphenylmethane derivative effectively even at low temperature (≈ 289 K). By comparisons of sub-systems, the US roles to S2O82-, ClO2-, and Fe0f were seriatim analyzed. US made the reaction order of multi-component system tend to within 1 (leading to de-order reaction), and widened pH activating range of the Fe0f by sonicate-polishing during the process of ClO2- co-activating S2O82-. US and Fe0f were affected by fluid eddy on activating S2O82-/ClO2-. The Fe0f had slight effect on the temperature of US bubble-water interface but the addition of ClO2- lowered it. The partitioning capacity of the above US reactive zone increased during the reaction. US and ClO2- could enrich the kinds of degradation intermediates. The contributions of free radicals (ClOx-based radicals, sulfate radicals (SO4-), and hydroxyl radicals (OH)) and non-free radicals (ClO2, and O = FeIV/V from ionic Fe under "-O-O-" of S2O82- and cyclic adjustment reaction of ClO2-) processes by sonochemical induction were equally important by corresponding detection means. Especially, real-time and online high-resolution mass spectrum by self-developing further confirmed the chain transfers of different free radicals due to US role. The findings expanded the application of sono-persulfate-based systems and improved understanding on activation mechanism.

5.
Ecol Evol ; 11(16): 10892-10903, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34429888

RESUMO

Microorganisms of plant phyllosphere play an important role in plant health and productivity and are influenced by abiotic and biotic factors. In this study, we investigated the phyllosphere bacterial communities of three cigar tobacco varieties cultivated in Guangcun (GC) and Wuzhishan (WZS), Hainan, China. Metagenomic DNA was extracted from tobacco leaf samples and sequenced by 16S rDNA amplicon sequencing. Our results showed that bacterial communities of cigar tobacco phyllosphere in GC exhibited remarkably higher alpha diversity than that in WZS. There was slight effect of tobacco genotype variations on the alpha diversity in both cultivation sites, and beta diversity and structure of bacterial community were not influenced significantly by the cultivation sites and tobacco varieties. Statistical analyses of species diversity unraveled that the dominant species in bacterial communities of cigar tobacco phyllosphere among all these samples were phylogenetically affiliated to Proteobacteria and Cyanobacteria. At the genus level, the most abundant microorganism was Limnobacter, followed by Brevundimonas, unidentified_Cyanobacteria, and Pseudomonas. Additionally, environmental conditions except for humidity were negatively correlated with the relative abundance of bacterial genera. Further analyses revealed that influence of site-specific factors on tobacco bacterial community was relatively higher than genotype-specific factors. In short, this study may contribute to the knowledge base of practical applications of bacterial inoculants for tobacco leaf production.

6.
Front Cardiovasc Med ; 8: 665993, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34095256

RESUMO

Background: Exercise training has been extensively studied in heart failure (HF) and psychological disorders, which has been shown to worsen each other. However, our understanding of how exercise simultaneously protect heart and brain of HF patients is still in its infancy. The purpose of this study was to take advantage of big data techniques to explore hotspots and frontiers of mechanisms that protect the heart and brain simultaneously through exercise training. Methods: We studied the scientific publications on related research between January 1, 2003 to December 31, 2020 from the WoS Core Collection. Research hotspots were assessed through open-source software, CiteSpace, Pajek, and VOSviewer. Big data analysis and visualization were carried out using R, Cytoscape and Origin. Results: From 2003 to 2020, the study on HF, depression, and exercise simultaneously was the lowest of all research sequences (two-way ANOVAs, p < 0.0001). Its linear regression coefficient r was 0.7641. The result of hotspot analysis of related keyword-driven research showed that inflammation and stress (including oxidative stress) were the common mechanisms. Through the further analyses, we noted that inflammation, stress, oxidative stress, apoptosis, reactive oxygen species, cell death, and the mechanisms related to mitochondrial biogenesis/homeostasis, could be regarded as the primary mechanism targets to study the simultaneous intervention of exercise on the heart and brain of HF patients with depression. Conclusions: Our findings demonstrate the potential mechanism targets by which exercise interferes with both the heart and brain for HF patients with depression. We hope that they can boost the attention of other researchers and clinicians, and open up new avenues for designing more novel potential drugs to block heart-brain axis vicious circle.

7.
Chemosphere ; 275: 130098, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33676276

RESUMO

The triphenylmethane derivative malachite green (tpmMaG) despite repeated prohibitions but is frequently detected in aquatic environment and draws emerging attention because of the potential poisonous effects. The polyaniline/persulfate with ultrasound catalysis (US/PANI-PS) was developed for tpmMaG removal. The effects of 12 factors and the optimization by response surface methodology (RSM) for tpmFG removal were evaluated based on the pseudo-first-kinetics (kobs). From free radical inhibition, the ratios of active species in US/PANI-PS (δ11 = 0.355, δ12 = 0.593) were close to that in US-PS (δ21 = 0.346, δ22 = 0.586) and different to that in PANI-PS and PS systems. A possible degradation pathway (hydroxylation, N-demethylation, deamination, and open-benzene ring) was explored by gas chromatography-mass spectrometer (GC/MS) and high performance liquid chromatography-mass spectrometer (HPLC-MS). The designed reactor involving the US-driven PANI was simulated by acoustic-piezoelectric interaction. From cavitation calculations, the estimated effective-mean temperature at bubble-water interface had little increasing (from 704 K to 711 K) after adding the PANI, however, the adsorption capacity of tpmMaG in reactive zone decreased from 0.0891 µM to 0.0787 µM. The mechanism (PANI hot turbo-micromotors) with US/PANI-PS was proposed. The tpmMaG was removed with a low treatment cost of 2.81 $⋅m-3 (the EE/O value 18.29 kWh⋅m-3) by US/PANI-PS, presenting a cost-effective treating process. The reusability tests and characterizations (contact angle, X-ray diffraction (XRD), and scanning electron microscope (SEM)) further confirmed the stability of PANI.


Assuntos
Preparações Farmacêuticas , Poluentes Químicos da Água , Adsorção , Aquicultura , Ultrassom , Poluentes Químicos da Água/análise
8.
Mol Cancer ; 16(1): 60, 2017 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-28288624

RESUMO

As an atypical member of cyclin dependent kinase family, Cyclin dependent kinase 5 (Cdk5) is considered as a neuron-specific kinase in the past decade due to the abundant existence of its activator p35 in post-mitotic neurons. Recent studies show that Cdk5 participates in a series of biological and pathological processes in non-neuronal cells, and is generally dysregulated in various cancer cells. The inhibition or knockdown of Cdk5 has been proven to play an anti-cancer role through various mechanisms, and can synergize the killing effect of chemotherapeutics. DNA damage response (DDR) is a series of regulatory events including DNA damage, cell-cycle arrest, regulation of DNA replication, and repair or bypass of DNA damage to ensure the maintenance of genomic stability and cell viability. Here we describe the regulatory mechanisms of Cdk5, its controversial roles in apoptosis and focus on its links to DDR and cancer.


Assuntos
Quinase 5 Dependente de Ciclina/metabolismo , Dano ao DNA , Neoplasias/genética , Neoplasias/metabolismo , Animais , Apoptose , Pontos de Checagem do Ciclo Celular , Quinase 5 Dependente de Ciclina/antagonistas & inibidores , Quinase 5 Dependente de Ciclina/genética , Replicação do DNA , Regulação Neoplásica da Expressão Gênica , Humanos , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Ligação Proteica , Transdução de Sinais/efeitos dos fármacos
9.
J Environ Sci (China) ; 25(2): 254-61, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23596943

RESUMO

Three treatments, sediment plus lake water (S+W), sterilized sediment plus lake water (SS+W), and sediment plus filtered lake water (S+FW), were recruited to investigate the growth characteristics of algae during pre-bloom and the importance of algal inocula in the water column and sediment. The results showed that in the water column, biomass of all algae increased in all treatments when recruitment was initiated, whereas this tendency differed among treatments with further increment of temperature. The process of algal growth consisted of two stages: Stage I, the onset of recruitment and Stage II, the subsequent growth of algae. Compared with S+W, in Stage I, SS+W significantly increased the biomass of cyanophytes by 178.70%, and decreased the biomass of non-cyanophytes by 43.40%; In Stage II, SS+W notably stimulated the growth of all algae, thus incurring the occurrence of phytoplankton bloom. Further analyses revealed that both metabolic activity and photochemical activity of algae were enhanced in SS+W, which resulted from the releasing of nutrients from sediment. These results suggest that algal growth in Stage II and algal inocula in the water column can be important factors for the formation of phytoplankton bloom. In addition, possible mechanisms promoting algal recruitment and subsequent growth of algae were explored.


Assuntos
Eutrofização/fisiologia , Fitoplâncton/crescimento & desenvolvimento , China , Lagos
10.
Huan Jing Ke Xue ; 34(1): 150-5, 2013 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-23487931

RESUMO

The growth and physiology of bloom-forming cyanobacterium Microcystis aeruginosa were determined by the flow cytometry when exposed to rice straw extract for 15 d. The cell growth, cell integrity, mitochondrial transmembrane potential, and esterase activity were used to evaluate the physiological response in Microcystis aeruginosa. Rice straw extract stored for 5 days significantly inhibited the growth of Microcystis aeruginosa in a concentration-dependent way; Most of the algae cells (> 98%) remained complete membranes in all the concentration treatments; Compared with the control cultures, the rice straw induced both negative and positive effects on the esterase activity for each test within 4 days, while the inhibition exceeded the stimulation effect. After a 7 d exposure, only the inhibition effect was found. Neither the inhibited nor stimulated effects was observed after algae exposure from 10 d to 15 d. Evident changes was found in the membrane potential during 7 d experiment, whereas inhibition effect became weaker after 10 d and 15 d exposure, in consistent with the result of esterase activity. These results confirmed that the rice straw extract might provide both dominant inhibition and relatively weak stimulation effects. After a long time exposure, inhibition effect became limited while stimulation effect disappeared. The action of rice straw may be algistatic (preventing algal growth) but not algicidal (killing algae).


Assuntos
Microcystis/crescimento & desenvolvimento , Oryza/química , Feromônios/análise , Feromônios/farmacologia , Extratos Vegetais/farmacologia , Técnicas de Cultura , Potenciais da Membrana/efeitos dos fármacos , Microcystis/efeitos dos fármacos , Microcystis/fisiologia , Caules de Planta/química
11.
J Hazard Mater ; 181(1-3): 602-8, 2010 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-20576352

RESUMO

Decolorization of Acid Red GR by a newly isolated biphenyl-degrading bacterium, Dyella ginsengisoli LA-4 was presented in this paper. The optimal decolorization conditions were determined by response surface methodology (RSM) based on the rotatable central composite design. The results indicated that strain LA-4 possessed the highest decolorizing activity under anaerobic conditions with inoculation amount 6.49%, pH 7.06 and temperature 29 degrees C. Some ions such as Cu(2+), Zn(2+) could inhibit the decolorization, whereas 1 mmol/L of Mg(2+), Ca(2+), Co(2+), Fe(3+), Ni(2+) and Mn(2+) had no effects on the process. It was demonstrated that anthraquinone as a redox mediator could significantly accelerate the reduction process of azo dyes.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Rodaminas/metabolismo , Anaerobiose , Antraquinonas , Compostos de Bifenilo , Cor , Corantes Fluorescentes/metabolismo , Métodos , Oxirredução
12.
Water Sci Technol ; 61(7): 1819-27, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20371941

RESUMO

Oxygen has been so far addressed as the most preferable terminal electron acceptor in the cathodes of microbial fuel cells (MFCs). However, to reduce the oxygen reduction overpotential at the cathode surface, eco-unfriendly and costly catalysts have been commonly employed. Here, we pursued the possibility of using a high surface area electrode to reduce the cathodic reaction overpotential rather than the utilization of catalyzed materials. A dual chambered MFC reactor was designed with the use of graphite-granule electrodes and a permeable membrane. The performance of the reactor in terms of electricity generation and organic removal rate was examined under a continuous-feed manner. Results showed that the maximum volumetric power of 4.4+/-0.2 W/m(3) net anodic compartment (NAC) was obtained at a current density of 11+/-0.5 A/m(3) NAC. The power output was improved by increasing the electrolyte ionic strength. An acceptable effluent quality was attained when the organic loading rate (OLR) of 2 kgCOD/m(3) NAC d was applied. The organic removal rate seemed to be less affected by shock loading. Our system can be suggested as a promising approach to make MFC-based technology economically viable for wastewater treatment applications. This study shows that current generation can be remarkably improved in comparison with several other studies using a low-surface-area plain graphite electrode.


Assuntos
Fontes de Energia Bioelétrica , Conservação dos Recursos Naturais , Grafite/química , Eliminação de Resíduos Líquidos , Reatores Biológicos , Eletrodos , Membranas Artificiais
13.
J Hazard Mater ; 179(1-3): 729-34, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20381236

RESUMO

One high efficient biphenyl-degrading strain Dyella ginsengisoli LA-4 was inoculated into biphenyl-contaminated soil for bioaugmentation in this study. The results showed that bioaugmentation could accelerate the startup period of the biphenyl bioremediation process compared with the non-augmented one. PCR-DGGE fingerprints demonstrated that both of the diversity and pattern of microbial community were affected by the addition of strain LA-4 and biphenyl. Biphenyl-utilizing populations gradually increased and become the dominant species. The introduced strain LA-4 could be persistent and co-exist well with the indigenous populations. However, both of the strain LA-4 and indigenous microorganisms in the bioaugmented system would be partially inhibited by Zn(2+) and Ni(2+). This study suggests that it is feasible and potentially useful to remediate biphenyl-contaminated soil using bioaugmentation with D. ginsengisoli LA-4.


Assuntos
Biodegradação Ambiental , Compostos de Bifenilo/química , Recuperação e Remediação Ambiental/métodos , Microbiologia do Solo , Poluentes do Solo/química , Xanthomonadaceae/metabolismo , Análise por Conglomerados , DNA/genética , DNA/isolamento & purificação , Impressões Digitais de DNA , Eletroforese , Metais/química , População , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Xanthomonadaceae/genética
14.
Biochemistry (Mosc) ; 75(1): 101-9, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20331430

RESUMO

We demonstrate that activation of nuclear factor kappaB (NF-kappaB) in neurons is neuroprotective in response to kainic acid (KA)-induced excitotoxicity. Combination of Western blotting, immunocytochemistry, and electrophoresis mobility shift assay showed that KA exposure induced a fast but transient nuclear translocation of the NF-kappaB p65 subunit and increased DNA-binding activity of NF-kappaB in primary cultured cortical neurons. The transient NF-kappaB activity was associated with upregulation of antiapoptotic Bcl-xL and XIAP gene products revealed by real-time PCR. Knockdown of p65 decreased neuronal viability and antiapoptotic gene expression. In addition, we showed that KA-stimulated DNA-binding activity of NF-kappaB was associated with reactive oxygen species and calcium signals, using AMPA/KA receptor antagonist, calcium chelator, and antioxidant. These results suggest that the fast and transient activation of NF-kappaB initiated by calcium signals is one of the important proximal events in response to KA-induced excitotoxicity, which has neuroprotective effect against KA-induced apoptosis.


Assuntos
Sinalização do Cálcio/efeitos dos fármacos , NF-kappa B/metabolismo , Neurônios/metabolismo , Animais , Apoptose , Células Cultivadas , Ácido Caínico/toxicidade , Neurônios/citologia , Interferência de RNA , Ratos , Ratos Sprague-Dawley , Receptores de Ácido Caínico/metabolismo , Fator de Transcrição RelA/genética , Fator de Transcrição RelA/metabolismo
15.
Free Radic Biol Med ; 48(4): 597-608, 2010 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-20006702

RESUMO

Mitochondria are critical regulators of cell death, a key feature of neurodegeneration. Reactive oxygen species (ROS) are crucial to Ca(2+)-mediated effects of glutamate receptor activation leading to neuronal degeneration. Tetramethylpyrazine (TMP) is a principal ingredient of Ligusticum wallichi Franchat (a Chinese herb), used for treatment of cardiovascular and cerebrovascular ischemic diseases. However, its protection against oxidative brain injury associated with excessive activation of glutamate receptors is unknown. In this study, we demonstrate TMP neuroprotection against kainate-induced excitotoxicity in vitro and in vivo. We found that TMP could partly alleviate kainate-induced status epilepticus in rats and prevented and rescued neuronal loss in the hippocampal CA3 but not the CA1 region. The partial prevention and rescue of neuronal loss by TMP were attributable to the preservation of the structural and functional integrity of mitochondria, evidenced by maintaining the mitochondrial membrane potential, ATP production, and complex I and III activities. Stabilization of mitochondrial function was linked to the observation that TMP could function as a reductant/antioxidant to quench ROS, block lipid peroxidation, and protect enzymatic antioxidants such as glutathione peroxidase and glutathione reductase. These results suggest that TMP may protect against oxidative brain injury by stabilization of mitochondrial function through quenching of ROS.


Assuntos
Hipocampo/metabolismo , Ácido Caínico/farmacologia , Mitocôndrias/metabolismo , Pirazinas/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Antioxidantes/metabolismo , Cálcio/metabolismo , Agonistas de Aminoácidos Excitatórios/farmacologia , Peroxidação de Lipídeos , Masculino , Medicina Tradicional Chinesa , Neurônios/patologia , Estresse Oxidativo , Extratos Vegetais/farmacologia , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio
16.
Bioprocess Biosyst Eng ; 31(4): 315-21, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17909860

RESUMO

Simultaneous organics removal and bio-electrochemical denitrification using a microbial fuel cell (MFC) reactor were investigated in this study. The electrons produced as a result of the microbial oxidation of glucose in the anodic chamber were transferred to the anode, which then flowed to the cathode in the cathodic chamber through a wire, where microorganisms used the transferred electrons to reduce the nitrate. The highest power output obtained on the MFCs was 1.7 mW/m(2) at a current density of 15 mA/m(2). The maximum volumetric nitrate removal rate was 0.084 mg NO(3)(-)-N cm(-2) (electrode surface area) day(-1). The coulombic efficiency was about 7%, which demonstrated that a substantial fraction of substrate was lost without current generation.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Eletroquímica/instrumentação , Nitritos/metabolismo , Compostos Orgânicos/isolamento & purificação , Compostos Orgânicos/metabolismo , Biodegradação Ambiental , Desenho de Equipamento , Análise de Falha de Equipamento
17.
Neurosci Lett ; 403(1-2): 103-8, 2006 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-16701950

RESUMO

The AMPA receptor subunit GluR2 is downregulated in neurons following a wide range of neurological insults. Here we report that suppression of GluR2 gene promoter activity is associated with kainate (KA)-induced downregulation of GluR2 subunit levels in primary cultured cortical neurons. RT-PCR and Northern blotting showed a significant decrease in GluR2 mRNA in cultured neurons after KA exposure. Transfection of cultured neurons with an expression vector pGL3-GluR2(-298/+283), where the reporter gene firefly luciferase was driven by the GluR2 promoter, revealed that KA exposure suppressed the transcriptional activation of the GluR2 promoter. Furthermore, the expression of the RE1-silencing transcription factor (REST) was increased in KA-exposed cortical neurons; enhanced binding of REST to RE1-like silencer element in the proximal promoter of the GluR2 subunit gene was evidenced by electrophoresis mobility shift assay. Chromatin immunoprecipitation showed that suppressed activity of the GluR2 promoter in cultured neurons after KA exposure was related to deacetylation of histone H4. These results indicate that REST as a crucial factor binds to RE1-like silencer element in the GluR2 promoter, suppressing transcription of the GluR2 subunit gene during KA exposure. Our data suggest that transcriptional suppression of the GluR2 subunit gene may contribute at least in part to downregulation of GluR2 subunit protein in neurons during KA exposure. Because our experiments showed a reduction of glutamate release in KA-exposed cortical neurons, REST may play a latent role in delayed neuronal death or in seizure-induced tolerance.


Assuntos
Córtex Cerebral/metabolismo , Ácido Caínico/metabolismo , Neurônios/metabolismo , Receptores de AMPA/antagonistas & inibidores , Proteínas Repressoras/biossíntese , Fatores de Transcrição/biossíntese , Acetilação , Animais , Northern Blotting , Células Cultivadas , Córtex Cerebral/citologia , Imunoprecipitação da Cromatina , Regulação para Baixo , Ensaio de Desvio de Mobilidade Eletroforética , Genes Reporter , Histonas/metabolismo , Ácido Caínico/toxicidade , Luciferases de Vaga-Lume/antagonistas & inibidores , Luciferases de Vaga-Lume/genética , Neurônios/efeitos dos fármacos , Regiões Promotoras Genéticas , Subunidades Proteicas/antagonistas & inibidores , Subunidades Proteicas/genética , RNA Mensageiro/antagonistas & inibidores , Ratos , Ratos Sprague-Dawley , Receptores de AMPA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Elementos Silenciadores Transcricionais
18.
Neoplasia ; 6(6): 802-12, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15720807

RESUMO

8-Chloro-adenosine (8-Cl-Ado) is a potent chemotherapeutic agent whose cytotoxicity in a variety of tumor cell lines has been widely investigated. However, the molecular mechanisms are uncertain. In this study, we found that exposure of human lung cancer cell lines A549 (p53-wt) and H1299 (p53-depleted) to 8-Cl-Ado induced cell arrest in the G2/M phase, which was accompanied by accumulation of binucleated and polymorphonucleated cells resulting from aberrant mitosis and failed cytokinesis. Western blotting showed the loss of phosphorylated forms of Cdc2 and Cdc25C that allowed progression into mitosis. Furthermore, the increase in Ser10-phosphorylated histone H3-positive cells revealed by fluorescence-activated cell sorting suggested that the agent-targeted cells were able to exit the G2 phase and enter the M phase. Immunocytochemistry showed that microtubule and microfilament arrays were changed in exposed cells, indicating that the dynamic instability of microtubules and microfilaments was lost, which may correlate with mitotic dividing failure. Aberrant mitosis resulted in mitotic catastrophe followed by varying degrees of apoptosis, depending on the cell lines. Thus, 8-Cl-Ado appears to exert its cytotoxicity toward cells in culture by inducing mitotic catastrophe.


Assuntos
Adenosina/farmacologia , Ciclo Celular/efeitos dos fármacos , Inibidores do Crescimento/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Mitose/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Western Blotting , Linhagem Celular Tumoral , Citometria de Fluxo , Humanos
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