Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Bioresour Technol ; 302: 122865, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32004814

RESUMO

Fermentative caproate production from wastewater is attractive but is currently limited by the low product purity and concentration. In this work, continuous, selective production of caproate from acetate and ethanol, the common products of wastewater anaerobic fermentation, was achieved in an anaerobic membrane bioreactor (AnMBR). The reactor was continuously operated for over 522 days without need for chemical cleaning. With an ethanol-to-acetate ratio of 3.0, the effluent caproate concentration was 2.62 g/L on average and the caproate ratio in liquid products reached 74%. Further raising the influent ethanol content slightly increased the effluent caproate level but lowered the product selectivity and resulted in microbial inhibition. The Clostridia (the major caproate-producing bacteria) and Methanobacterium species (which consume hydrogen to alleviate microbial inhibition) was significantly enriched in the acclimated sludge. Our results imply a great potential of utilizing AnMBR to recover caproate from the effluent of wastewater acidogenic fermentation process.


Assuntos
Reatores Biológicos , Caproatos , Anaerobiose , Bactérias Anaeróbias , Fermentação
2.
Bioresour Technol ; 297: 122448, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31771810

RESUMO

In this work, a single microbial electrochemical system was developed for multiple goals simultaneously - CO2 reduction, biogas purification, upgrading and sulfur recovery. This system consists of a methanogen-inoculated biocathode for CO2 reduction and a ferrous ion (Fe2+)-mediated abiotic anode for hydrogen sulfide (H2S) oxidation. In the cathodic chamber, methane production rate of 20.6 ± 1.0 µmol·h-1 and high upgrading level (up to 98.3% methane content) were achieved. In the anodic chamber, H2S was completely removed and selectively converted into elemental sulfur particles. The system showed stable performance during continuous operation for treating both pure CO2 and mixed gases, with a cathodic coulombic efficiency of up to 85.2%. This simple system holds a great potential for practical application for biogas upgrading and sulfur recovery from waste water/gases.


Assuntos
Biocombustíveis , Dióxido de Carbono , Metano , Enxofre , Águas Residuárias
3.
Environ Int ; 129: 273-278, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31146161

RESUMO

China's national development strategy now prioritizes environmental protection over economic growth, which has driven a rapid development of China's wastewater sector. In particular, the treatment capacity of municipal wastewater treatment plants (WWTPs) has been substantially strengthened and stricter effluent quality control enforced. However, the operating performance of most WWTPs is still poor and does not meet the sustainable development demands. In this study, the current status of WWTPs operation in China was comprehensively analyzed, the key barriers to improving the plants operating efficiency were identified by taking into account the different plant scales, geographic distribution, discrepancy between cities and counties, and the influence of environmental policies and supplementary facilities. The underdeveloped sewer network was mainly responsible for the low operating ratios (i.e., utilization degree of the designed treatment capacity) of the plants (76% in counties and 85% in cities) especially for those in north China, although the situation is plant specific because a considerable fraction of plants (19%) are still running under overload condition. Other challenges include the high energy consumption of the plants (0.313 kWh/m3), and severely lagged implementation of sludge disposal (up to 40% sludge was still improperly disposed), arising mainly from the poor management on the sewer and sludge. Lastly, several possible directions of improvement to overcome these barriers were discussed. This work may provide valuable implications for optimizing municipal wastewater management in China towards higher efficiency and sustainability.


Assuntos
Eliminação de Resíduos Líquidos , Águas Residuárias/análise , China , Esgotos , Eliminação de Resíduos Líquidos/instrumentação
4.
Sci Total Environ ; 664: 133-139, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-30739848

RESUMO

A non-radical reaction between peroxysulfates and phenolic compounds, as important structural moieties of natural organic matters, has been reported recently, implying new opportunities for environmental remediation without need for catalyst or energy input. However, this approach seems to be ineffective for halogenated aromatic compounds, an important disinfection by-products (DBPs). Here, we shed light on the interactions between peroxymonosulfate (PMS) and chlorophenols and the influential factors. The results show that the chlorophenols transformation kinetics were highly dependent on the solution pH and chlorophenol species: raising the pH significantly accelerated the chlorophenols degradation, and at alkaline pH the removal rates of different chlorophenols were in the order of trichlorophenol > dichlorophenol > chlorophenol > tetrachlorophenol. The faster degradation of pollutants with more chlorine groups was mainly due to their relatively higher dissociation degree, which favors a direct pollutant-PMS interaction to generate radicals for their degradation. The chlorophenol degradation intermediate (i.e. benzoquinone) further mediated the generation of singlet oxygen at alkaline pH, thereby contributing to accelerated pollutant removal. The slower degradation of tetrachlorophenol than other chlorophenols was likely due to its strong electrostatic epulsion to PMS which restricted the reaction. Our work unveils the chlorophenols degradation mechanisms in PMS reaction system, which may facilitate a better understanding and optimization of advanced oxidation processes for pollution control to reduce potential DBPs accumulation.

5.
Bioresour Technol ; 260: 61-67, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29614452

RESUMO

Recovery of volatile fatty acids (VFAs) from wastewater is an important route for wastewater valorization. Selective acidogenic fermentation enables an efficient production of VFAs from wastewater, whereas electrodialysis (ED) provides an effective approach to concentrate VFAs. However, these two processes have not been coupled in one single system previously. In this study, an acidogenesis-ED integrated system that coupled a continuous acidogenesis with a batch process of VFA concentration was developed for recovery of high-concentration VFAs from wastewater. Under 20.0 V voltage, the acetate was concentrated by 4-fold and the propionate and butyrate were concentrated by over 3-fold in the integrated system after 528-h operation. The declined VFAs recovery ratios at the later stage due to significant reverse diffusion indicate a need to prevent product over-accumulation. This work demonstrated the feasibility of the acidogenesis-ED integrated reactor for wastewater valorization and discussed the remaining challenges and opportunities.


Assuntos
Ácidos Graxos Voláteis , Águas Residuárias , Reatores Biológicos , Ácido Butírico , Fermentação , Concentração de Íons de Hidrogênio , Propionatos , Esgotos
6.
Artigo em Inglês | MEDLINE | ID: mdl-28880235

RESUMO

Risk of metals in urban soils is less studied, compared to that in other types of soils, hindering accurate assessment of human exposure to metals. In this study, the concentrations of five metals (As, Cd, Cr, Pb, and Hg) were analyzed in 167 surface soil samples collected from Suzhou city and their potential ecological and human health risks were assessed. The mean concentrations of As, Cd, Pb, and Hg except Cr, were higher than the background values in Jiangsu Province. Metal concentrations varied among districts, where sites of high contamination showed a punctate distribution. Principal components and correlation analyses revealed that As, Pb, and Cd could originate from the same sources. The geo-accumulation (Igeo) and potential ecological risk indices (RI) were calculated and the relatively low values of Igeo (<0) and RI (<150) suggested generally low ecological risk. The noncarcinogenic risks of the metals were relatively low for Suzhou residents (i.e., average hazard index or HI: 0.1199 for adults and 0.5935 for children, <1), while the total carcinogenic risks (TCR) of Cr and As were acceptable (TCR in the range of 1.0 × 10-6 to 1.0 × 10-4). Children faced a higher threat than adults. Results of Monte-Carlo simulations were lower than those obtained from models using deterministic parameters. Of all the uncertain parameters, the ingestion rate and body weight were the most sensitive for adults and children, respectively, while As was an important factor for both. The results as well as the factors controlling risks of metals could help better understand the risks of metals in urban soils of industrial cities in China.


Assuntos
Arsênico/análise , Metais Pesados/análise , Poluentes do Solo/análise , Adulto , Criança , China , Cidades , Monitoramento Ambiental/métodos , Humanos , Indústrias , Método de Monte Carlo , Medição de Risco
7.
Sci Total Environ ; 586: 1162-1169, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28228239

RESUMO

Municipal wastewater treatment plants (WWTPs) are an important source of pharmaceuticals released into the environment. Understanding how various pharmaceuticals are distributed and handled in WWTPs is a prerequisite to optimize their abatement. Here we investigated the spatial distribution and removal efficiencies pharmaceuticals in China's WWTPs. A total of 35 pharmaceuticals in wastewater samples from 12 WWTPs at different cities of China were analyzed. Among these detected pharmaceuticals, caffeine showed the highest concentration (up to 1775.98ngL-1) in the WWTP influent. In addition, there were significant regional differences in pharmaceutical distribution with higher influent concentrations of total pharmaceuticals detected in WWTPs in the northern cities than the southern ones. The state-of-the-art treatment processes were generally inefficient in removing pharmaceuticals. Only 14.3% of pharmaceuticals were removed effectively (mean removal efficiency>70%), while 51.4% had a removal rate of below 30%. The anaerobic/anoxic/oxic (AAO)-membrane bioreactor (MBR) integrated process and sequencing batch reactor (SBR) showed better performance than the AAO and oxidation ditch (OD) processes. Ofloxacin, erythromycin-H2O, clarithromycin, roxithromycin and sulfamethoxazole in WWTP effluents exhibited a high or medium ecological risk and deserved special attention.


Assuntos
Preparações Farmacêuticas/isolamento & purificação , Eliminação de Resíduos Líquidos , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , China , Cidades , Análise Espacial
8.
Environ Pollut ; 219: 837-845, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27521292

RESUMO

Heavy metal pollution is a global issue severely constraining aquaculture practices, not only deteriorating the aquatic environment but also threatening the aquaculture production. One promising solution is adopting aquaponics systems where a synergy can be established between aquaculture and aquatic plants for metal sorption, but the interactions of multiple metals in such aquatic plants are poorly understood. In this study, we investigated the absorption behaviors of Cu(II) and Cd(II) in water by water hyacinth roots in both single- and binary-metal systems. Cu(II) and Cd(II) were individually removed by water hyacinth roots at high efficiency, accompanied with release of protons and cations such as Ca2+ and Mg2+. However, in a binary-metal arrangement, the Cd(II) sorption was significantly inhibited by Cu(II), and the higher sorption affinity of Cu(II) accounted for its competitive sorption advantage. Ionic exchange was identified as a predominant mechanism of the metal sorption by water hyacinth roots, and the amine and oxygen-containing groups are the main binding sites accounting for metal sorption via chelation or coordination. This study highlights the interactive impacts of different metals during their sorption by water hyacinth roots and elucidates the underlying mechanism of metal competitive sorption, which may provide useful implications for optimization of phytoremediation system and development of more sustainable aquaculture industry.


Assuntos
Eichhornia/metabolismo , Metais Pesados/metabolismo , Raízes de Plantas/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Cádmio/metabolismo , Cobre/metabolismo , Troca Iônica , Água/química
9.
Exp Ther Med ; 12(2): 641-648, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27446255

RESUMO

Stem cells are used with increasing success in the treatment of renal tubular injury. However, whether mesenchymal stem cells (MSC) differentiate into renal tubular epithelial cells remains controversial. The aims of the present study were to observe the localization of human embryonic MSCs (hMSCs) in the kidneys of newborn mice, and to investigate hMSC differentiation into tubular epithelium. Primary culture hMSCs were derived from 4-7-week-old embryos and labeled with the cell membrane fluorescent dye PKH-26. The degree of apoptosis, cell growth, differentiation and localization of hMSCs with and without this label were then determined using immunohistochemical methods and flow cytometry. hMSCs and PKH26-labeled hMSCs were revealed to differentiate into chondrocytes and adipocytes, and were demonstrated to have similar proliferative capability. In the two cell types, the antigens CD34 and CD45, indicative of hematopoietic lineages, were not expressed; however, the expression of the mesenchymal markers CD29 and CD90 in MSCs, was significantly increased. During a 4-week culture period, laser confocal microscopy revealed that PKH26-labeled hMSCs in the kidneys of newborn mice gradually dispersed. Two weeks after the injection of the PKH26-labeled cells, the percentage of PKH26-labeled hMSCs localized to the renal tubules was 10±2.1%. In conclusion, PKH26 labeling has no effect on hMSC differentiation, proliferation and mesenchymal cell surface features, and hMSCs injected into the kidneys of newborn mice may transform to renal tubule epithelium.

10.
Bioresour Technol ; 149: 38-43, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24084202

RESUMO

Efficient decolorization of reactive blue 13 was achieved by a combined use of anaerobic sludge and zero-valent iron (ZVI), and the underlying mechanism of this process was elucidated, Addition of 1.0 g/L ZVI into sludge accelerated the decolorization, with the decoloration ratio after 1-h treatment increased by 29.4% compared with the sum of the individual systems, indicating a synergy between the sludge and ZVI. Meanwhile, substantial changes in sludge morphology and microbial community were observed. The increased dye removal by ZVI was mainly attributed to: (1) a directly chemical reduction and aggregation; and (2) creation of a more favorable pH and anaerobic environment for microorganisms. The acid production by acidogens also partially offset the pH rise in ZVI corrosion and would alleviate ZVI deactivation. This work might offer valuable implications for the optimization and practical application of ZVI-anaerobic sludge processes for treatment of azo dyes or other recalcitrant pollutants.


Assuntos
Compostos Azo/química , Corantes/química , Ferro/farmacologia , Naftalenossulfonatos/química , Esgotos/microbiologia , Anaerobiose/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Bactérias/genética , Sequência de Bases , Biodegradação Ambiental , Cor , Eletroforese em Gel de Gradiente Desnaturante , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Hibridização in Situ Fluorescente , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Salinidade , Análise de Sequência de DNA , Difração de Raios X
11.
Am J Med Sci ; 346(2): 113-22, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23085672

RESUMO

INTRODUCTION: The transplantation of mesenchymal stem cells (MSCs) has been reported to be a promising approach in the treatment of acute lung injury. However, the poor efficacy of transplanted MSCs is one of the serious handicaps in the progress of MSC-based therapy. Therefore, the purpose of this study was to investigate whether the pretreatment of human embryonic MSCs (hMSCs) with an antioxidant, namely N-acetylcysteine (NAC), can improve the efficacy of hMSC transplantation in lung injury. METHODS: In vitro, the antioxidant capacity of NAC-pretreated hMSCs was assessed using intracellular reactive oxygen species (ROS) and glutathione assays and cell adhesion and spreading assays. In vivo, the therapeutic potential of NAC-pretreated hMSCs was assessed in a bleomycin-induced model of lung injury in nude mice. RESULTS: The pretreatment of hMSCs with NAC improved antioxidant capacity to defend against redox imbalances through the elimination of cellular ROS, increasing cellular glutathione levels, and the enhancement of cell adhesion and spreading when exposed to oxidative stresses in vitro. In addition, the administration of NAC-pretreated hMSCs to nude mice with bleomycin-induced lung injury decreased the pathological grade of lung inflammation and fibrosis, hydroxyproline content and numbers of neutrophils and inflammatory cytokines in bronchoalveolar lavage fluid and apoptotic cells, while enhancing the retention and proliferation of hMSCs in injured lung tissue and improving the survival rate of mice compared with results from untreated hMSCs. CONCLUSIONS: The pretreatment of hMSCs with NAC could be a promising therapeutic approach to improving cell transplantation and, therefore, the treatment of lung injury.


Assuntos
Acetilcisteína/farmacologia , Bleomicina/efeitos adversos , Células-Tronco Embrionárias/efeitos dos fármacos , Pneumopatias/induzido quimicamente , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos/efeitos adversos , Antioxidantes/metabolismo , Sobrevivência Celular , Humanos , Pneumopatias/prevenção & controle , Camundongos , Camundongos Nus , Espécies Reativas de Oxigênio
12.
Reprod Biomed Online ; 25(4): 425-33, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22874064

RESUMO

As an abundant source that involves fewer ethical considerations, human abnormally fertilized zygotes are superior to oocytes as therapeutic cloning recipients of nuclear transfer. However, more effective manipulation conditions should be developed for somatic cell nuclear transfer (SCNT) studies using human abnormally fertilized zygotes as recipients. The present study found that the use of cytochalasin B was not necessary for, and even harmful to, the enucleation of human zygotes. This study also decreased the DNA methylation levels in reconstructed embryos using a DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-aza-dC), in an attempt to correct the abnormalities in DNA methylation that might play an important role in the failure of embryo development. After 5-aza-dC treatment and nuclear transfer (NT-Aza group), 32.7% of reconstructed embryos developed to the 8-cell stage, which is a much higher percentage than that of the nuclear transfer only (NT) group (11.1%). The DNA methylation level in the NT-Aza group was significantly lower than that of the NT group, as determined by 5-methylcytosine immunodetection. Based on the present results, this study recommends performing the enucleation procedure without cytochalasin B treatment and using 5-aza-dC in the culture of reconstructed embryos in human SCNT studies.


Assuntos
Azacitidina/análogos & derivados , Metilases de Modificação do DNA/antagonistas & inibidores , Ectogênese/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Técnicas de Transferência Nuclear , Zigoto/efeitos dos fármacos , 5-Metilcitosina/metabolismo , Adulto , Azacitidina/farmacologia , China , Metilação de DNA/efeitos dos fármacos , Decitabina , Feminino , Fertilização In Vitro , Humanos , Infertilidade/metabolismo , Infertilidade/patologia , Infertilidade/terapia , Cinética , Masculino , Microscopia Confocal , Microscopia de Fluorescência , Mitose/efeitos dos fármacos , Injeções de Esperma Intracitoplásmicas , Zigoto/metabolismo , Zigoto/patologia
13.
Am J Physiol Renal Physiol ; 300(1): F207-18, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20943766

RESUMO

The implantation of mesenchymal stem cells (MSC) has been reported as a new technique to restore renal tubular structure and improve renal function in acute kidney injury (AKI). Vascular endothelial growth factor (VEGF) plays an important role in the renoprotective function of MSC. Whether upregulation of VEGF by a combination of MSC and VEGF gene transfer could enhance the protective effect of MSC in AKI is not clear. We investigated the effects of VEGF-modified human embryonic MSC (VEGF-hMSC) in healing cisplatin-injured renal tubular epithelial cells (TCMK-1) with a coculture system. We found that TCMK-1 viability declined 3 days after cisplatin pretreatment and that coculture with VEGF-hMSC enhanced cell protection via mitogenic and antiapoptotic actions. In addition, administration of VEGF-hMSC in a nude mouse model of cisplatin-induced kidney injury offered better protective effects on renal function, tubular structure, and survival as represented by increased cell proliferation, decreased cellular apoptosis, and improved peritubular capillary density. These data suggest that VEGF-modified hMSC implantation could provide advanced benefits in the protection against AKI by increasing antiapoptosis effects and improving microcirculation and cell proliferation.


Assuntos
Lesão Renal Aguda/prevenção & controle , Cisplatino/efeitos adversos , Transplante de Células-Tronco Mesenquimais/métodos , Fator A de Crescimento do Endotélio Vascular/farmacologia , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células , Técnicas de Cocultura , Humanos , Camundongos , Camundongos Nus
14.
J Dermatol ; 36(7): 403-9, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19583688

RESUMO

Wound repair and functional reconstruction are two key aspects for treatment of skin injury. Research on cell source for skin repair has become a focus of study. The immune rejection induced by allograft cells and the limited source of autologous epidermal stem cells have led to more attention on the multipotent adult progenitor cells (MAPC). In this study, we examined the influence of the local environment of skin injury on the migration and differentiation of MAPC in nude mice. The homing of MAPC to the wounds and the epidermal differentiation of MAPC were investigated by detecting the expression of specific antigens of rat major histocompatibility complex I (MHC-I) antigen and the tracing markers. Three weeks after transplantation, hair follicle-like structure appeared and rat MHC-I antigen was positive in the follicles of the healed skin. PKH26-labeled cells expressing cytokeratin were found in the regenerated follicle-like structures, sebaceous glands and sweat glands. Our findings indicate that MAPC can migrate to the skin injury site and the hair follicles, and participate in skin wound healing by differentiating into epidermal cells, which contributes to the theoretical research of MAPC plasticity and provides theoretical evidence for clinical application of transplantation therapy with MAPC.


Assuntos
Células-Tronco Adultas/citologia , Células-Tronco Adultas/transplante , Células Epidérmicas , Células-Tronco Multipotentes/citologia , Células-Tronco Multipotentes/transplante , Animais , Animais Recém-Nascidos , Células da Medula Óssea/citologia , Diferenciação Celular , Movimento Celular , Antígenos de Histocompatibilidade Classe I/metabolismo , Camundongos , Camundongos Nus , Ratos , Ratos Sprague-Dawley , Regeneração , Pele/imunologia , Pele/lesões , Pele/patologia , Transplante Heterólogo , Cicatrização
15.
Ann Hematol ; 87(6): 431-8, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18338169

RESUMO

Future application of adult stem cells in clinical therapies largely depends on the successful isolation of homogeneous stem cells with high plasticity. Multipotent adult progenitor cells (MAPCs) are thought to be a more primitive stem cell population capable of extensive in vitro proliferation with no senescence or loss of differentiation capability. The present study was aimed to find a less complicated and more economical protocol for obtaining single cell-derived MAPCs and understand the molecule mechanism of multi-lineage differentiation of MAPCs. We successfully obtained a comparatively homogeneous population of MAPCs and confirmed that single cell-derived MAPCs were able to transcribe Oct4 and genes of three germ layers simultaneously, and differentiate into multiple lineages. Our observations suggest that single cell-derived MAPCs under appropriate circumstances could maintain not only characteristics of stem cells but multi-lineage differentiation potential through quantitative modulation of corresponding regulating gene expression, rather than switching on expression of specific genes.


Assuntos
Células-Tronco Multipotentes/metabolismo , Fator 3 de Transcrição de Octâmero/genética , Células-Tronco/metabolismo , Adulto , Antígenos CD/análise , Diferenciação Celular , Regulação da Expressão Gênica , Humanos , Células-Tronco Multipotentes/citologia , RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células-Tronco/citologia
16.
Zhonghua Xue Ye Xue Za Zhi ; 27(7): 474-8, 2006 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-17147252

RESUMO

OBJECTIVE: To optimize the culture conditions for clonal isolation of rat bone marrow-derived multipotential adult progenitor cells (rMAPC) and identify their surface markers and differentiation potentials. METHODS: By using a low concentration of fetal bovine serum culture medium, rMAPCs were primarily isolated from bone marrow by attachment culture and clonal-like cells were selected by single cell limiting dilution. The surface antigens of the cloned rMAPC were analyzed by flow cytometry and immunocytochemistry. Multi-differentiation capacities were evaluated by lipoblasts and osteoblasts and neuroblasts differentiation induction. The expressions of Oct-4 and three embryonic germ layer markers were detected by RT-PCR. RESULTS: Single cell-derived rMAPC could be expanded to passage 20 in vitro which still maintained active proliferation ability. The expanded rMAPCs expressed CD71, alpha-SMA and vimentin, but not CD34, CD44 and CD45. About 83% of the rMAPCs was in the resting phase(G0 + G1) of cell cycle and 17% in S + G2 + M phase. They could be induced to differentiate into adipogenic cells, osteogenic cells and neural like cells. RT-PCR demonstrated that there were expressions of oct-4 gene and three embryonic germ layer markers on the rMAPCs. CONCLUSIONS: Cloned rMAPC can maintain the phenotypes of stem cell during in vitro culturing. It might be an potential adult stem cell source for therapeutic stem cell transplanting and tissue engineering.


Assuntos
Células da Medula Óssea/citologia , Células-Tronco Mesenquimais/citologia , Animais , Técnicas de Cultura de Células , Linhagem Celular , Meios de Cultivo Condicionados , Citometria de Fluxo , Masculino , Ratos , Ratos Sprague-Dawley
17.
J Leukoc Biol ; 80(2): 424-32, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16793913

RESUMO

Hepatitis C virus (HCV) infection correlates with human immune disorders characterized by abnormal activation and proliferation of lymphocytes. Interaction of HCV major envelope protein E2 with susceptible cells occurs at an early stage of the viral infection. HCV tropism for susceptible cells may elicit cellular signaling events implicated in the viral pathogenicity, and E2 protein is known to be responsible for the tropism. We documented previously that HCV E2 protein was capable of activating extracellular signal-regulated kinase (ERK) in human hepatoma Huh-7 cells. Here, ERK and p38 mitogen-activated protein kinase (MAPK) signaling pathways were investigated in human T lymphoma cell line Molt-4 in response to HCV E2 protein. Binding of HCV E2 protein to Molt-4 cells was detectable, and such interaction was a determinant for recognition and delivery of the E2 signal to intracellular pathways. Activation of ERK and p38 MAPK was specifically induced following the HCV E2-cell interaction. CD81 and low-density lipoprotein receptor (LDLR), proposed cellular receptors for HCV, were expressed naturally on Molt-4 cells. CD81 and LDLR were shown to mediate HCV E2-induced activation of ERK and p38 MAPK. In CD81-deficient U937 cells, levels of ERK and p38 MAPK activation and cell proliferation induced by HCV E2 protein were lower than those in Molt-4 cells. Furthermore, cell proliferation and secretion of interferon-gamma and interleukin-10 by Molt-4 cells were promoted by HCV E2 protein. Therefore, ERK and p38 MAPK signaling pathways were up-regulated by HCV E2 protein without synergetic stimulation, which was accompanied by alterations of cell behavior.


Assuntos
MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Linfoma de Células T/metabolismo , Regulação para Cima , Proteínas do Envelope Viral/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Antígenos CD/genética , Linhagem Celular Tumoral , Proliferação de Células , Citocinas/metabolismo , Humanos , Receptores de LDL/fisiologia , Transdução de Sinais , Tetraspanina 28 , Proteínas do Envelope Viral/metabolismo
18.
Breast Cancer Res Treat ; 89(1): 5-14, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15666191

RESUMO

Shp-2, an src homology (SH) two-containing phosphotyrosine phosphatase, appears to be involved in cytoplasmic signaling downstream of a variety of cell surface receptors. It also plays an important role in the control of cell spreading, migration, and cytoskeletal architecture. In our study, abrogation of SHP-2 catalytic activity with a'dominant-negative mutant (SHP-2C > S) displayed an increased number of focal adhesion, high expression of E-cadhenrin and phosphorylation of the focal adhesion kinase (FAK). Interestingly, the cells expressing SHP-2C > S showed reduced IL-1beta-stimulated chemotaxis compared with either mock- or SHP-2 wild type-transfected cells. We also found that SHP-2-GFP-transfected cell lines did not express E-cadherin nearly and produced high level of the matrix metalloproteinase MMP-9 in the supernatants. The loss of E-cadherin-mediated adhesion and the increase of MMP-9-induced migration had been shown to play an important role in the transition of epithelial tumors from a benign to an invasive state. These findings have raised the possibility that SHP-2 can promote the cancer cell to invasion the distant tissues. To determine whether SHP-2 promotes invasion and metastasis, we transfected MCF-7 breast cancer cell lines with SHP-2-GFP, SHP-2C > S-GFP and analyzed the effects of the SHP-2 on cell migration, invasion, and metastasis. In vitro, SHP-2-GFP-transfected cells migrated more efficiently, showed an increased invasion of Matrigel, and adhered less efficiently to monolayers of fibroblast cells. When injected into the abdominal cavity of nude mice, SHP-2-GFP-transfected cells metastasized widely to the lung, kidney, but MCF-7 with SHP-2C > S-GFP was not observed in the these organs. These results demonstrate that SHP-2 promotes invasion and metastasis of MCF-7 with the loss of E-cadherin, the dephosphorylation of FAK and the secretion of MMP-9 induced by IL-1beta.


Assuntos
Neoplasias da Mama/fisiopatologia , Caderinas/metabolismo , Movimento Celular , Adesões Focais/química , Metaloproteinase 9 da Matriz/metabolismo , Metástase Neoplásica/fisiopatologia , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Tirosina Quinases/química , Animais , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Feminino , Quinase 1 de Adesão Focal , Proteína-Tirosina Quinases de Adesão Focal , Expressão Gênica , Técnicas In Vitro , Interleucina-1 , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Camundongos Nus , Metástase Neoplásica/genética , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Proteínas Tirosina Fosfatases/genética
19.
Mol Carcinog ; 42(2): 93-6, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15593371

RESUMO

There have been extensive observations that RNA containing repetitive elements accumulates in transformed cells and tumor tissues. In the present study, we first obtained result consistent with previous observations by in situ hybridization. Then we used primer extension analysis to determine the level of polymerase III directed Alu RNA and found an increased expression of Alu RNA in hepatocellular carcinoma.


Assuntos
Elementos Alu , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/genética , RNA Polimerase III/fisiologia , Transcrição Genética , Primers do DNA/química , Humanos , Hibridização In Situ , Dados de Sequência Molecular , RNA/metabolismo , RNA Polimerase III/metabolismo , RNA Mensageiro/metabolismo
20.
Cell Tissue Res ; 318(3): 525-31, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15578271

RESUMO

Human embryonic germ (hEG) cell is a very important alternative pluripotent stem cell resource. We describe the derivation of hEG cells from human embryonic fetal gonads over 6-8 weeks postconception. A large number of EG-like cell clumps were obtained at passage 1 and thus facilitated the following routine culture when the donor tissues were trypsinized with gentle pipetting and plated on feeder layer cells in the initial culture. Eight diploid hEG cell lines have been cultivated in vitro for extended periods while maintaining expression of markers characteristic of pluripotent stem cells. Human EG cells expressed transcription factor Oct4, a marker of pluripotency in mouse EG cells, at a high and steady level. Expression of markers indicative of differentiation along the three germ lineages was also observed in EBs. High level of alkaline phosphatase activity was shown in EG cells. These encouraging findings provide a starting point for potential applicability of hEG cells.


Assuntos
Linhagem da Célula , Embrião de Mamíferos/citologia , Células Germinativas/citologia , Células-Tronco Pluripotentes/citologia , Fosfatase Alcalina/metabolismo , Biomarcadores/análise , Diferenciação Celular , Células Cultivadas , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos/metabolismo , Técnica Indireta de Fluorescência para Anticorpo , Idade Gestacional , Humanos , Cariotipagem , Fator 3 de Transcrição de Octâmero , Células-Tronco Pluripotentes/metabolismo , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA