Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Cell ; 184(7): 1895-1913.e19, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33657410

RESUMO

A dysfunctional immune response in coronavirus disease 2019 (COVID-19) patients is a recurrent theme impacting symptoms and mortality, yet a detailed understanding of pertinent immune cells is not complete. We applied single-cell RNA sequencing to 284 samples from 196 COVID-19 patients and controls and created a comprehensive immune landscape with 1.46 million cells. The large dataset enabled us to identify that different peripheral immune subtype changes are associated with distinct clinical features, including age, sex, severity, and disease stages of COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was found in diverse epithelial and immune cell types, accompanied by dramatic transcriptomic changes within virus-positive cells. Systemic upregulation of S100A8/A9, mainly by megakaryocytes and monocytes in the peripheral blood, may contribute to the cytokine storms frequently observed in severe patients. Our data provide a rich resource for understanding the pathogenesis of and developing effective therapeutic strategies for COVID-19.


Assuntos
COVID-19/imunologia , Megacariócitos/imunologia , Monócitos/imunologia , RNA Viral , SARS-CoV-2/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , China , Estudos de Coortes , Citocinas/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , RNA Viral/isolamento & purificação , Análise de Célula Única , Transcriptoma/imunologia , Adulto Jovem
3.
PLoS One ; 16(2): e0246685, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33561161

RESUMO

According to the 'novel weapons hypothesis', invasive success depends on harmful plant biochemicals, including allelopathic antimicrobial roots exudate that directly inhibit plant growth and soil microbial activity. However, the combination of direct and soil-mediated impacts of invasive plants via allelopathy remains poorly understood. Here, we addressed the allelopathic effects of an invasive plant species (Rhus typhina) on a cultivated plant (Tagetes erecta), soil properties and microbial communities. We grew T. erecta on soil samples at increasing concentrations of R. typhina root extracts and measured both plant growth and soil physiological profile with community-level physiological profiles (CLPP) using Biolog Eco-plates incubation. We found that R. typhina root extracts inhibit both plant growth and soil microbial activity. Plant height, Root length, soil organic carbon (SOC), total nitrogen (TN) and AWCD were significantly decreased with increasing root extract concentration, and plant above-ground biomass (AGB), below-ground biomass (BGB) and total biomass (TB) were significantly decreased at 10 mg·mL-1 of root extracts. In particular, root extracts significantly reduced the carbon source utilization of carbohydrates, carboxylic acids and polymers, but enhanced phenolic acid. Redundancy analysis shows that soil pH, TN, SOC and EC were the major driving factors of soil microbial activity. Our results indicate that strong allelopathic impact of root extracts on plant growth and soil microbial activity by mimicking roots exudate, providing novel insights into the role of plant-soil microbe interactions in mediating invasion success.


Assuntos
Alelopatia/fisiologia , Desenvolvimento Vegetal/fisiologia , Solo/química , Biomassa , Carbono/metabolismo , Espécies Introduzidas/tendências , Microbiota/fisiologia , Nitrogênio/metabolismo , Raízes de Plantas/fisiologia , Plantas/metabolismo , Plantas/microbiologia , Rhus/metabolismo , Rhus/toxicidade , Microbiologia do Solo , Tagetes/crescimento & desenvolvimento , Tagetes/metabolismo
4.
Cancer Manag Res ; 12: 3469-3476, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32523377

RESUMO

Background: Ursolic acid (UA), a primary bioactive triterpenoid, was reported as an anti-cancer agent. However, the current knowledge of UA and its potential anti-cancer mechanisms and targets in breast cancer cells are limited. In this study, we aimed to illustrate the potential mechanisms and targets of UA in breast cancer cells MCF-7. Methods: The effect of UA on cell growth was determined in MCF-7 cells by MTT assay. The anti-tumor mechanism of UA was evaluated by microarray, CAMP, and Western blot. Moreover, the molecular docking between UA and potential receptors were predicted by iGEMDOCK software. Results: The result of MTT assay demonstrated that UA could inhibit MCF-7 cell growth with IC50 values of 20 µM. Microarray and CMAP analysis, validated by Western blot, indicated that UA significantly modulated IKK/NF-κB, RAF/ERK pathways, and down-regulated the phosphorylation level of PLK1 in MCF-7 cells. Conclusion: Our data indicated that the anti-tumor effects of UA are due to the inhibited RAF/ERK pathway and IKK/NF-κB pathway. It could also be explained by the reduced phosphorylation of PLK1 in MCF-7 cells. This study provides a new insight for deep understanding of the new anti-cancer mechanisms of UA in MCF-7 breast cancer cells.

5.
Cancer Med ; 8(18): 7774-7780, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31670906

RESUMO

BACKGROUND: Cervical cancer is one of the most common causes of cancer-associated mortality among affected women in the world. At present, treatment with weekly cisplatin plus ionizing radiation (IR) therapy is the standard regimen for cervical cancer, especially for locally advanced cervical cancer. The purpose of this study is to determine whether FEN1 inhibitors could enhance the therapeutic effect of IR therapy. METHODS: Western blot was applied to determine the expression of FEN1- and apoptosis-related proteins. Cell growth inhibition assay and colony formation assay were used to determine the effects of FEN1 inhibitor and IR exposure for Hela cells in vitro. CRISPR technology was used to knockdown FEN1 expression level of 293T cells, and tumor xenograft in nude mice was employed to determine the effects of FEN1 inhibitor and IR exposure on tumor growth in vivo. RESULTS: Our data revealed that FEN1 is overexpressed in HeLa cell and can be upregulated further by IR. We also demonstrated that FEN1 inhibitor enhances IR sensitivity of cervical cancer in vitro and in vivo. CONCLUSION: FEN1 inhibitor SC13 could sensitize radiotherapy of cervical cancer cell.


Assuntos
Inibidores Enzimáticos/farmacologia , Endonucleases Flap/antagonistas & inibidores , Tolerância a Radiação/efeitos dos fármacos , Radiossensibilizantes/farmacologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Modelos Animais de Doenças , Feminino , Endonucleases Flap/genética , Endonucleases Flap/metabolismo , Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Células HeLa , Humanos , Camundongos , Radiação Ionizante , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Anat Rec (Hoboken) ; 302(12): 2193-2200, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31569304

RESUMO

Efforts have been made to find effective medical drugs for cervical cancer treatment. The incidence of cervical cancer ranks second among women, and is a serious threat to women's health. Aberrant activation of the nonreceptor protein tyrosine kinases such as Src is commonly observed in progressive stages of human tumors. Thus, targeting Src kinase could be a promising strategy for cervical cancer therapy. In this study, we explored the potential utility of bosutinib in the treatment of cervical cancer. We found that bosutinib, as a potent dual Src/Abl inhibitor, could exert anti-tumor effects on cervical cancer. Bosutinib inhibited cervical cancer cells proliferation and colony formation ability in a dose-dependent manner, and also induced apoptosis. Mechanistically, bosutinib effectively decreased the activity of Src/NF-κB/survivin signaling pathway. Our study provided a biological rationale to test bosutinib as a valuable therapeutic option for cervical cancer patients. Anat Rec, 302:2193-2200, 2019. © 2019 American Association for Anatomy.


Assuntos
Compostos de Anilina/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Nitrilas/farmacologia , Quinolinas/farmacologia , Survivina/antagonistas & inibidores , Neoplasias do Colo do Útero/tratamento farmacológico , Quinases da Família src/antagonistas & inibidores , Apoptose , Biomarcadores Tumorais , Movimento Celular , Proliferação de Células , Feminino , Humanos , NF-kappa B/genética , NF-kappa B/metabolismo , Survivina/genética , Survivina/metabolismo , Células Tumorais Cultivadas , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia , Quinases da Família src/genética , Quinases da Família src/metabolismo
7.
Comb Chem High Throughput Screen ; 22(6): 379-386, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31272350

RESUMO

AIM AND OBJECTIVE: Flap endonuclease-1 (FEN1) plays a central role in DNA replication and DNA damage repair process. In mammals, FEN1 functional sites variation is related to cancer and chronic inflammation, and supports the role of FEN1 as a tumor suppressor. However, FEN1 is overexpressed in multiple types of cancer cells and is associated with drug resistance, supporting its role as an oncogene. Hence, it is vital to explore the multi-functions of FEN1 in normal cell metabolic process. This study was undertaken to examine how the gene expression profile changes when FEN1 is downregulated in 293T cells. MATERIALS AND METHODS: Using the RNA sequencing and real-time PCR approaches, the transcript expression profile of FEN1 knockdown HEK293T cells have been detected for the next step evaluation, analyzation, and validation. RESULTS: Our results confirmed that FEN1 is important for cell viability. We showed that when FEN1 downregulation led to the interruption of nucleic acids related metabolisms, cell cycle related metabolisms are significantly interrupted. FEN1 may also participate in non-coding RNA processing, ribosome RNA processing, transfer RNA processing, ribosome biogenesis, virus infection and cell morphogenesis. CONCLUSION: These findings provide insight into how FEN1 nuclease might regulate a wide variety of biological processes, and laid the foundation for understanding the role of other RAD2 family nucleases in cell growth and metabolism.


Assuntos
Endonucleases Flap/genética , Endonucleases Flap/metabolismo , Neoplasias/genética , Ácidos Nucleicos/metabolismo , Viroses/genética , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , Endonucleases Flap/deficiência , Perfilação da Expressão Gênica , Células HEK293 , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , RNA-Seq , Viroses/metabolismo , Viroses/patologia
8.
J Cell Biochem ; 120(11): 18600-18607, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31338882

RESUMO

Lung cancer (especially, non-small cell lung cancer [NSCLC]) is one of the most malignant cancers in the world. Hinesol is the major component of the essential oil of Atractylodes lancea (Thunb.) DC and possesses the most promising anticancer function. However, the effects and molecular mechanism of hinesol on antiproliferation in NSCLC cells has not been well understood. In this study, we found that hinesol effectively inhibited the A549 and NCI-H1299 cells in a dose- and time-dependent manner by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay. In addition, hinesol induced cell cycle arrest at G0/G1 phase and apoptosis assessed by flow cytometry in A549 cells. Furthermore, Western blot analysis showed that hinesol decreased phosphorylation of mitogen-activated protein kinase, extracellular signal-regulated kinase, IκBα, and p65 inhibited the expressions of Bcl-2, cyclin D1 and upregulated the expression of Bax. Based on these results, hinesol might be a potential drug candidate of anti-NSCLC for therapy.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Atractylodes/química , Proliferação de Células/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , NF-kappa B/metabolismo , Sesquiterpenos/farmacologia , Compostos de Espiro/farmacologia , Células A549 , Proteínas Reguladoras de Apoptose/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Estrutura Molecular , Extratos Vegetais/farmacologia , Fase de Repouso do Ciclo Celular/efeitos dos fármacos , Sesquiterpenos/química , Compostos de Espiro/química , Fatores de Tempo
9.
Reprod Toxicol ; 81: 229-236, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30125682

RESUMO

Exposure to radiofrequency fields (RF) has been reported to induce adverse effects on testosterone production and its daily rhythm. However, the mechanisms underneath this effect remain unknown. In this study, male mice were exposed to 1800 MHz radiofrequency fields (RF, 40 µW/cm2 power intensity and 0.0553 W/Kg SAR) 2 h per day for 32 days. The data suggested that RF exposure: (i) significantly reduced testosterone levels, (ii) altered the expression of genes involved in its synthesis (Star, P450scc, P450c17 and 3ß-Hsd) in testicular tissue, (iii) significantly reduced regulatory protein CaMKI/RORα. Similar observations were also made in cultured primary Leydig cells exposed in vitro to RF. However, all of these observations were blocked by CaMK inhibitor, KN-93, and ionomycin reversed the down-regulation effects on intracellular [Ca2+]i and CaMKI/RORα expression induced by RF exposure. Thus, the data provided the evidence that RF-induced inhibition of testosterone synthesis might be mediated through CaMKI/RORα signaling pathway. Capsule: CaMKI/RORα signaling pathway was involved in the inhibition of testosterone synthesis induced by RF exposure.


Assuntos
Proteína Quinase Tipo 1 Dependente de Cálcio-Calmodulina/metabolismo , Membro 1 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Ondas de Rádio , Testosterona/metabolismo , Animais , Benzilaminas/farmacologia , Proteína Quinase Tipo 1 Dependente de Cálcio-Calmodulina/genética , Células Cultivadas , Ionomicina/farmacologia , Células Intersticiais do Testículo/metabolismo , Células Intersticiais do Testículo/efeitos da radiação , Masculino , Camundongos Endogâmicos C57BL , Membro 1 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Transdução de Sinais/efeitos da radiação , Sulfonamidas/farmacologia
10.
Artigo em Inglês | MEDLINE | ID: mdl-28878185

RESUMO

The hyporheic zone regulates physicochemical processes in surface-groundwater systems and can be an important source of heavy metals in fluvial systems. This study assesses the pore water concentrations and diffusive fluxes of heavy metals with respect to the vertical water exchange flux (VWEF) and sediment grain size. Water and sediment samples were collected on August 2016 from upstream Site 1 and downstream Site 2 along the Juehe River in Shaanxi Province, China. Streambed vertical hydraulic conductivity (Kv) and the VWEF were estimated via the standpipe permeameter test method and Darcy's law. The heavy metal concentrations in the pore water were measured and the diffusive fluxes were calculated using Fick's first law. The VWEF patterns were dominated by upward flow, and Site 1 featured higher values of Kv and VWEF. Higher Cu and Zn concentrations occurred near the channel centre with coarse sand and gravel and greater upward VWEFs because coarser sediment and greater upward VWEFs cause stronger metal desorption capacity. Additionally, Cu and Zn at the two sites generally diffused from pore water to surface water, potentially due to the upward VWEF. The VWEF and sediment grain size are likely crucial factors influencing the heavy metal concentrations and diffusive fluxes.


Assuntos
Sedimentos Geológicos/análise , Metais Pesados/análise , Rios/química , Poluentes Químicos da Água/análise , China , Difusão , Monitoramento Ambiental , Água Subterrânea/análise , Tamanho da Partícula , Porosidade
11.
Chemistry ; 22(47): 16796-16800, 2016 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-27662638

RESUMO

Seven luminescent iridium(III) complexes were prepared to investigate the relationships between chemical structures and properties of protein staining. For the first time, the effect of the main ligand, the π conjugation effect of the ancillary ligand, and the charge effect of organometallic complexes on protein staining has been revealed. Most importantly, this study gives the first experimental evidence of the potential applications of charge-neutral organometallic complexes in protein staining, which could open an avenue of exploiting novel protein staining agents in the future.

12.
J Microbiol Biotechnol ; 26(4): 700-9, 2016 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-26718472

RESUMO

The mitogen-activated protein kinase HOG1 (high-osmolarity glycerol response pathway) plays a crucial role in the response of yeast to hyperosmotic shock. Trichosporonoides oedocephalis produces large amounts of polyols (,e.g., erythritol and glycerol) in a culture medium. However, the effects of HOG1 gene knockout and environmental stress on the production of these polyols have not yet been studied. In this study, a To-HOG1 null mutation was constructed in T. oedocephalis using the loxP-Kan-loxP/Cre system as replacement of the targeted genes, and the resultant mutants showed much smaller colonies than the wild-type controls. Interestingly, compared with the wild-type strains, the results of shake-flask culture showed that To-HOG1 null mutation increased erythritol production by 1.44-fold while decreasing glycerol production by 71.23%. In addition, this study investigated the effects of citric acid stress on the T. oedocephalis HOG1 null mutants and the wild-type strain. When the supplementation of citric acid in the fermentation medium was controlled at 0.3% (w/v), the concentration of erythritol produced from the wild-type and To-HOG1 knockout mutant strains improved by 18.21% and 21.65%, respectively.


Assuntos
Basidiomycota/genética , Basidiomycota/metabolismo , Eritritol/biossíntese , Deleção de Genes , Proteínas Quinases Ativadas por Mitógeno/genética , Mutação , Técnicas de Cultura Celular por Lotes , Ácido Cítrico/farmacologia , Fermentação , Regulação Fúngica da Expressão Gênica , Técnicas de Inativação de Genes , Glicerol/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Estresse Fisiológico/genética , Transformação Genética
13.
Environ Sci Pollut Res Int ; 23(6): 5763-70, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26585454

RESUMO

Bombyx mori L. (B. mori) were exposed to cadmium chloride (CdCl2) incorporated in an artificial diet (0, 6.25, 12.5, 25, and 50 mg kg(-1)) throughout the larval stage. Changes in malondialdehyde (MDA) and reduced glutathione (GSH) contents and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), as well as their corresponding messenger RNA (mRNA) levels in the testes of the fifth instar larvae were evaluated. Additionally, spermatozoon deformation in the testes was examined. Upon Cd treatment, the MDA content in the testes was significantly increased in a concentration-dependent manner. Cd-exposed larvae had increased levels of glutathione. Pearson's correlation analysis revealed that SOD and CAT activities were positively correlated (R (2) = 0.605, P = 0.017). The changing trends in the mRNA levels of these enzymes were not always consistent with those of enzymatic activities. Alterations in GSH-Px activities and mRNA levels were positively correlated (R (2) = 0.771, P < 0.01). Morphological analysis revealed that Cd deformed and affected the maturation of spermatozoa. Our results collectively support a relationship between Cd and alterations in the levels of antioxidant enzymes in B. mori testes.


Assuntos
Bombyx/efeitos dos fármacos , Cloreto de Cádmio/farmacologia , Estresse Oxidativo , Espermatogênese/efeitos dos fármacos , Testículo , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Larva/metabolismo , Masculino , Malondialdeído/metabolismo , Superóxido Dismutase/metabolismo
14.
Reprod Biomed Online ; 31(5): 638-46, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26386639

RESUMO

The aim of the present study was to elucidate whether the GATA-4/SF-1 signalling pathway is involved in the inhibitory effects of melatonin on testosterone production in both the TM3 Leydig cell line and in C57BL/6J mice. In-vitro experiments demonstrated that melatonin treatment significantly reduced testosterone levels in cell culture medium (P < 0.05 or P < 0.01); and decreased intracellular cyclic adenosine monophospha accumulation (P < 0.05 or P < 0.01) and mRNA/protein expression of GATA-4, SF-1 (NR5A1), StAR, P450SCC (CYP11A1) and 3ß-HSD (P < 0.05 or P < 0.01). These effects were blocked by N-acetyl-2-benzyltryptamin, a melatonin receptor antagonist. Similar effects of melatonin on testosterone production (P < 0.05 or P < 0.01) and down-regulation of transcription factors GATA-4 and SF-1 (P < 0.01) were also observed in mice treated with intratesticular injections of melatonin. Overall, the data suggest that the inhibitory effects of melatonin on testosterone production are mediated via down-regulation of GATA-4 and SF-1 expression.


Assuntos
Fator de Transcrição GATA4/metabolismo , Células Intersticiais do Testículo/efeitos dos fármacos , Melatonina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Fator Esteroidogênico 1/metabolismo , Testosterona/biossíntese , Animais , Linhagem Celular , AMP Cíclico/metabolismo , Regulação para Baixo/efeitos dos fármacos , Células Intersticiais do Testículo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL
15.
Chronobiol Int ; 31(1): 123-33, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24117058

RESUMO

In this study, we explored the circadian effects of daily radiofrequency field (RF) exposure on reproductive functional markers in adult male Sprague-Dawley rats. Animals in circadian rhythm (as indicated by melatonin measurements), were divided into several groups and exposed to 1800 MHz RF at 205 µw/cm(2) power density (specific absorption rate 0.0405 W/kg) for 2 h/day for 32 days at different zeitgeber time (ZT) points, namely, ZT0, ZT4, ZT8, ZT12, ZT16 and ZT20. Sham-exposed animals were used as controls in the study. From each rat, testicular and epididymis tissues were collected and assessed for testosterone levels, daily sperm production and sperm motility, testis marker enzymes γ-GT and ACP, cytochrome P450 side-chain cleavage (p450cc) mRNA expression, and steroidogenic acute regulatory protein (StAR) mRNA expression. Via these measurements, we confirmed the existence of circadian rhythms in sham-exposed animals. However, rats exposed to RF exhibited a disruption of circadian rhythms, decreased testosterone levels, lower daily sperm production and sperm motility, down-regulated activity of γ-GT and ACP, as well as altered mRNA expression of cytochrome P450 and StAR. All of these observations were more pronounced when rats were exposed to RF at ZT0. Thus, our findings indicate potential adverse effects of RF exposure on male reproductive functional markers, in terms of both the daily overall levels as well as the circadian rhythmicity.


Assuntos
Ritmo Circadiano/efeitos da radiação , Fosfatase Ácida/metabolismo , Animais , Biomarcadores/metabolismo , Epididimo/efeitos da radiação , Masculino , Melatonina/biossíntese , Ondas de Rádio , Ratos , Ratos Sprague-Dawley , Motilidade Espermática/efeitos da radiação , Espermatozoides/efeitos da radiação , Testículo/efeitos da radiação , Testosterona/biossíntese , gama-Glutamiltransferase/metabolismo
16.
J Chromatogr A ; 1294: 152-6, 2013 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-23651650

RESUMO

This work explores the potential of multi-walled carbon nanotubes as an agglomerated material for ion chromatography stationary phases for the separation of inorganic anions. Polyelectrolytes with quaternary ammonium groups were introduced onto the carbon nanotube surface, based on condensation polymerization of 1,4-butanediol diglycidyl ether (BDDE) and methylamine (MA). Quaternized multi-walled carbon nanotubes (Q-MWCNTs) were electrostatically adsorbed onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to generate the anion exchanger, which were confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A 100mm×4.0mm i.d. column was packed with Q-MWCNTs agglomerated PS-DVB particles, with a capacity of 56µequiv./column. Separation of inorganic anions, such as F(-), Cl(-), NO2(-), Br(-), NO3(-), SO4(2-) and PO4(3-) were performed. The stationary phase was rigid, chemically stable and showed good ion-exchange characteristics.


Assuntos
Cromatografia por Troca Iônica/instrumentação , Nanotubos de Carbono/química , Poliestirenos/química , Compostos de Vinila/química , Adsorção , Ânions/química , Ânions/isolamento & purificação , Cromatografia por Troca Iônica/métodos
17.
Food Chem ; 139(1-4): 144-8, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23561090

RESUMO

A single pump cycling-column-switching technique has been developed for the iodate analysis in edible salt. Homemade high exchange capacity columns were adopted for the separation of iodate and chloride. Iodate could be retained and concentrated in a homemade concentrator column after eluents passing through the suppressor. With UV detection, iodate exhibited satisfactory linearity in the range of 0.1-10.0 mg/L with a correlation coefficient of 0.9996. The detection limit (LOD) was 45.53 µg/L, based on the signal-to-noise ratio of 3 (S/N=3) and a 100 µL injection volume. Relative standard deviations (RSDs) for retention time, peak area and peak height were all less than 2.1%. Recoveries of added iodate were in the range of 98.4-101.6% for the spiked samples. The quantitative determination of iodate in edible salt was accomplished by this column-switching technique, without any pretreatment and interference. The results on six samples were statistically compared with results determined by conventional titrimetric method.


Assuntos
Cromatografia por Troca Iônica/métodos , Iodatos/análise , Iodo/análise , Cloreto de Sódio na Dieta/análise , Cromatografia por Troca Iônica/instrumentação , Limite de Detecção
18.
Asian Pac J Cancer Prev ; 14(11): 6363-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24377533

RESUMO

Atractylis lancea (Thunb.) DC. (AL), an important medicinal herb in Asia, has been shown to have anti-tumor effects on cancer cells, but the involved mechanisms are poorly understood. This study focused on potential effects and molecular mechanisms of AL on the proliferation of the Hep-G2 liver cancer cell line in vitro. Cell viability was assessed by MTT test in Hep-G2 cells incubated with an ethanol extract of AL. Then, the effects of AL on apoptosis and cell cycle progression were determined by flow cytometry. Telomeric repeat amplification protocol (TRAP) assays was performed to investigate telomerase activity. The mRNA and protein expression of human telomerase reverse transcriptase (hTERT) and c-myc were determined by real-time RT-PCR and Western blotting. Our results show that AL effectively inhibits proliferation in Hep-G2 cells in a concentration- and time-dependent manner. When Hep-G2 cells were treated with AL after 48h,the IC50 was about 72.1 µg/ mL. Apoptosis was induced by AL via arresting the cells in the G1 phase. Furthermore, AL effectively reduced telomerase activity through inhibition of mRNA and protein expression of hTERT and c-myc. Hence, these data demonstrate that AL exerts anti-proliferative effects in Hep-G2 cells via down-regulation of the c-myc/hTERT/ telomerase pathway.


Assuntos
Atractylis/química , Extratos Vegetais/farmacologia , Proteínas Proto-Oncogênicas c-myc/genética , Telomerase/genética , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Regulação para Baixo/efeitos dos fármacos , Fase G1/efeitos dos fármacos , Fase G1/genética , Células Hep G2 , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/genética , Extratos Vegetais/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Mensageiro/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Telomerase/metabolismo
19.
J Chromatogr A ; 1251: 154-159, 2012 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-22771256

RESUMO

A simple ion chromatographic method for simultaneous detection of iodide and iodate in a single running was proposed, with columns packed with homemade functionalized polystyrene-divinylbenzene (PS-DVB) resins and column-switching technique. Homemade resins were functionalized with controllable amounts of quaternary ammonium groups. The low-capacity anion-exchange column and high-capacity anion-exchange column were prepared, due to the resins having different exchange capacities. With this method, iodide and iodate in povidone iodine solution were detected simultaneously in a short time with iodide being eluted off first. A series of standard solutions consisting of target anions of various concentrations from 0.01 mg/L to 100 mg/L were analyzed. Each anion exhibited satisfactory linearity, with correlation coefficient r ≥ 0.9990. The detection limits (LODs) for iodide and iodate obtained by injecting 100 µL of sample were 5.66 and 14.83 µg/L (S/N=3), respectively. A spiking study was performed with satisfactory recoveries between 101.2% and 100.6% for iodide and iodate.


Assuntos
Cromatografia por Troca Iônica/instrumentação , Cromatografia por Troca Iônica/métodos , Iodatos/análise , Iodetos/análise , Povidona-Iodo/química , Calibragem , Limite de Detecção , Poliestirenos , Reprodutibilidade dos Testes , Soluções/química
20.
Waste Manag ; 29(4): 1347-53, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19087900

RESUMO

Ex situ nitrification and sequential in situ denitrification represents a novel approach to nitrogen management at landfills. Simultaneous ammonia and organics removal was achieved in a continuous stirred tank reactor (CSTR). The results showed that the maximum nitrogen loading rate (NLR) and the maximum organic loading rate (OLR) was 0.65gNl(-1)d(-1) and 3.84gCODl(-1)d(-1), respectively. The ammonia and chemical oxygen demand (COD) removal was over 99% and 57%, respectively. In the run of the CSTR, free ammonia (FA) inhibition and low dissolved oxygen (DO) were found to be key factors affecting nitrite accumulation. In situ denitrification was studied in a municipal solid waste (MSW) column by recalculating nitrified leachate from CSTR. The decomposition of MSW was accelerated by the recirculation of nitrified leachate. Complete reduction of total oxidized nitrogen (TON) was obtained with maximum TON loading of 28.6gNt(-1)TSd(-1) and denitrification was the main reaction responsible. Additionally, methanogenesis inhibition was observed while TON loading was over 11.4gNt(-1)TSd(-1) and the inhibition was enhanced with the increase of TON loading.


Assuntos
Reatores Biológicos , Nitrogênio/isolamento & purificação , Compostos Orgânicos/isolamento & purificação , Gerenciamento de Resíduos/métodos , Poluentes Químicos da Água/isolamento & purificação , Amônia/análise , Bactérias/metabolismo , Biodegradação Ambiental , Metano/biossíntese , Nitritos/análise , Oxigênio/análise , Resíduos/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...