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1.
Genomics ; 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31226482

RESUMO

B. longum LTBL16 is a potential probiotic strain that was isolated from healthy centenarians in Bama, China. In vitro experiments show that B. longum LTBL16 has a strong antioxidant activity and the complete genome of B. longum LTBL16 was sequenced in this work. The genome consists of one 2,430,682 bp circular chromosome that is plasmid free. The circular chromosome has a GC content of 61.23% and contains 2071 coding sequences (CDSs), 4 rRNA manipulators and 55 tRNA coding genes. Genetic analysis showed that at least five protein-coding genes were associated with antioxidant activity, and the abundance of these genes may be related to free radical scavenging rates and oxygen tolerance. In addition, the safety of B. longum LTBL16 was evaluated using a virulence factor database and antibiotic resistance gene database. The results indicate that B. longum LTBL16 has the good potential for the development and utilization as a probiotic.

2.
J Agric Food Chem ; 67(19): 5361-5373, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30612424

RESUMO

During the past 20 years, many studies have focused on polyphenol compounds for their potential beneficial health effects. Flavonoids represent a large class of phenolic compounds found in fruits, vegetables, nuts, grains, cocoa, tea, and other beverages. Flavonoids have shown antioxidant and anti-inflammatory activities. Given the putative relationship between inflammation and insulin resistance, the consumption of flavonoids or flavonoid-rich foods has been suggested to reduce the risk of diabetes by targeting inflammatory signals. This is the first comprehensive review summarizing the current research progress on the inhibition of inflammation and alleviation of insulin resistance by flavonoids as well as the mechanistic link between these disorders. Laboratory and human studies on the activities of major flavonoids (flavones, isoflavones, flavonols, etc.) are discussed.


Assuntos
Flavonoides/administração & dosagem , Inflamação/tratamento farmacológico , Resistência à Insulina , Extratos Vegetais/administração & dosagem , Animais , Flavonoides/química , Humanos , Inflamação/genética , Inflamação/imunologia , Estrutura Molecular , Extratos Vegetais/química , Transdução de Sinais/efeitos dos fármacos
3.
J Funct Foods ; 46: 1-11, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30364631

RESUMO

Theaflavin-3, 3'-digallate (TF3) is a phenolic compound extracted from black tea. We previously demonstrated that TF3 selectively inhibited ovarian cancer cells. Ovarian cancer has high death rate because of acquired cisplatin resistance. We aimed to investigate the synergistic effect of TF3 and cisplatin (CDDP) against cisplatin resistant ovarian cancer cells. In the present study, combination treatment with TF3 and CDDP showed a synergistic cytotoxic effect in A2780/CP70 and OVCAR3 cells. Combination treatment showed a synergistic pro-apoptotic effect and synergistically induced G1/S phase cell cycle arrest. Synergistic apoptosis was accompanied by regulating protein expression of cleaved caspase 3/7, cytochrome c, Bax and Bcl-2. Combination treatment induced G1/S phase cell cycle arrest via regulating protein expression of cyclin A2, cyclin D1, cyclin E1 and CDK2/4. Combination treatment could synergistically down-regulate Akt phosphorylation in both cell lines. TF3 may be used as an adjuvant for the treatment of advanced ovarian cancer.

4.
Int J Mol Sci ; 19(1)2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-29301278

RESUMO

Ovarian cancer has the highest fatality rate among the gynecologic cancers. The side effects, high relapse rate, and drug resistance lead to low long-term survival rate (less than 40%) of patients with advanced ovarian cancer. Theaflavin-3,3'-digallate (TF3), a black tea polyphenol, showed less cytotoxicity to normal ovarian cells than ovarian cancer cells. We aimed to investigate whether TF3 could potentiate the inhibitory effect of cisplatin against human ovarian cancer cell lines. In the present study, combined treatment with TF3 and cisplatin showed a synergistic cytotoxicity against A2780/CP70 and OVCAR3 cells. Treatment with TF3 could increase the intracellular accumulation of platinum (Pt) and DNA-Pt adducts and enhanced DNA damage induced by cisplatin in both cells. Treatment with TF3 decreased the glutathione (GSH) levels and upregulated the protein levels of the copper transporter 1 (CTR1) in both cells, which led to the enhanced sensitivity of both ovarian cancer cells to cisplatin. The results imply that TF3 might be used as an adjuvant to potentiate the inhibitory effect of cisplatin against advanced ovarian cancer.


Assuntos
Biflavonoides/farmacologia , Catequina/análogos & derivados , Proteínas de Transporte de Cátions/metabolismo , Cisplatino/farmacologia , Glutationa/metabolismo , Neoplasias Ovarianas/metabolismo , Catequina/farmacologia , Linhagem Celular Tumoral , Adutos de DNA/metabolismo , Dano ao DNA , Sinergismo Farmacológico , Feminino , Humanos , Neoplasias Ovarianas/patologia , Regulação para Cima/efeitos dos fármacos
5.
Int J Oncol ; 51(5): 1508-1520, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29048667

RESUMO

Adverse side effects and acquired resistance to conventional chemotherapy based on platinum drive the exploration of other selective anticancer drugs. Theaflavin­3-gallate (TF2a) and theaflavin­3'-gallate (TF2b), theaflavin monomers in black tea, exhibited a potent growth inhibitory effect on cisplatin-resistant ovarian cancer A2780/CP70 cells and were less cytotoxic to normal ovarian IOSE-364 cell line. Flow cytometry analysis and western blotting indicated that TF2a and TF2b induced apoptosis and G1 cell cycle arrest in ovarian cancer A2780/CP70 cells. Hoechst 33342 staining was used to confirm the apoptotic effect. Downregulation of CDK2 and CDK4 for TF2a and CDK2 and cyclin E1 for TF2b led to the accumulation of cells in G1 phase. TF2a and TF2b induced apoptosis and G1 through p53-dependent pathways. TF2a and TF2b induced DNA damage through ATM/Chk/p53 pathway. TF2a and TF2b also induced inhibition of A2780/CP70 cells through Akt and MAPK pathways. The results of this study implied that TF2a and TF2b might help prevent and treat platinum-resistant ovarian cancer.


Assuntos
Biflavonoides/administração & dosagem , Catequina/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ácido Gálico/análogos & derivados , Neoplasias Ovarianas/tratamento farmacológico , Apoptose/efeitos dos fármacos , Biflavonoides/química , Catequina/química , Linhagem Celular Tumoral , Cisplatino/administração & dosagem , Cisplatino/efeitos adversos , Dano ao DNA/efeitos dos fármacos , Feminino , Citometria de Fluxo , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Ácido Gálico/administração & dosagem , Ácido Gálico/química , Humanos , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Proteína Oncogênica v-akt/genética , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Transdução de Sinais/efeitos dos fármacos , Chá/química
6.
J Chromatogr Sci ; 55(5): 495-496, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28203771

RESUMO

A fast ultrahigh performance liquid chromatography (UPLC) method has been developed for simultaneous analysis of caffeine and 13 index polyphenols-gallic acid, 8 primary catechins and 4 primary theaflavins in black tea. The method was evaluated in terms of linearity, precision, accuracy and recovery. The lower limits of detection and quantification were in the range of 0.05-0.91 and 0.15-3.00 mg/L, respectively. Satisfactory linearity with correlation coefficient (R2 > 0.9992), interday and intraday precision with the relative standard deviations (<2.94% and <5.06%, respectively), interday and intraday accuracy with relative errors (REs, -5.34% < REs < 4.36% and -5.36% < REs < 7.07%, respectively) and recovery (95.81-104.48%) were achieved for all target compounds. The UPLC method was applied for the analysis of the 14 compounds in 6 black tea samples.


Assuntos
Cafeína/análise , Cromatografia Líquida de Alta Pressão/métodos , Polifenóis/análise , Chá/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
7.
Molecules ; 21(12)2016 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-27941615

RESUMO

Obesity is one of the most common nutritional diseases worldwide. This disease causes health problems, such as dyslipidemia, hyperglycemia, hypertension and inflammation. There are drugs used to inhibit obesity. However, they have serious side effects outweighing their beneficial effects. Black tea, commonly referred to as "fermented tea", has shown a positive effect on reducing body weight in animal models. Black tea polyphenols are the major components in black tea which reduce body weight. Black tea polyphenols are more effective than green tea polyphenols. Black tea polyphenols exert a positive effect on inhibiting obesity involving in two major mechanisms: (i) inhibiting lipid and saccharide digestion, absorption and intake, thus reducing calorie intake; and (ii) promoting lipid metabolism by activating AMP-activated protein kinase to attenuate lipogenesis and enhance lipolysis, and decreasing lipid accumulation by inhibiting the differentiation and proliferation of preadipocytes; (iii) blocking the pathological processes of obesity and comorbidities of obesity by reducing oxidative stress. Epidemiological studies of the health relevance between anti-obesity and black tea polyphenols consumption remain to be further investigated.


Assuntos
Antioxidantes/farmacologia , Polifenóis/farmacologia , Chá/química , Perda de Peso/efeitos dos fármacos , Animais , Humanos
8.
Mater Sci Eng C Mater Biol Appl ; 62: 323-8, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26952430

RESUMO

Polydiallyldimethylammonium chloride, PDDA, was used as a stabilizer and linker for functionalized TiO2 nanotubes (TiO2 NTs). Self-assembled process with palladium nanoparticles (NPs) was successfully synthesized and used for the oxidation of glucose on glassy carbon electrodes. Based on the voltammetric and amperometric results, Pd NPs efficiently catalyzed the oxidation of glucose at -0.05 V in the presence of 0.1 M NaCl and showed excellent resistance toward interference poisoning from such interfering species as ascorbic acid, uric acid and urea. To further increase sensitivity, the Pd NPs-PDDA-TiO2 NTs/GCE was electrochemically treated with H2SO4 and NaOH, the glucose oxidation current was magnified 2.5 times than that before pretreatments due to greatly enhancing the electron transport property of the sensor based on the increased defect sites and surface oxide species. In view of the physiological level of glucose, the wide linear concentration range of glucose (4×10(-7)-8×10(-4)M) with a detection limit of 8×10(-8)M (S/N=3) was obviously good enough for clinical application.


Assuntos
Técnicas Eletroquímicas , Glucose/análise , Nanopartículas Metálicas/química , Nanotubos/química , Paládio/química , Titânio/química , Catálise , Limite de Detecção , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura , Oxirredução , Difração de Raios X
9.
Mater Sci Eng C Mater Biol Appl ; 49: 640-647, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25686993

RESUMO

In this work, a novel zinc phthalocyanine tetrasulfonic acid (ZnTsPc)-functionalized graphene nanocomposites (f-GN) was synthesized by a simple and efficient electrostatic self-assembly method, where the positive charged GN decorated by (3-aminopropyl) triethoxysilane (APTES) was self-assemblied with ZnTsPc, a two dimensional (2-D) molecules. It not only enhanced its stability for the hybrid structure, but also avoided the reaggregation of ZnTsPc or f-GN themselves. Based on layered ZnTsPc/f-GN nanocomposites modified glassy carbon electrode, a rapid and sensitive sensor was developed for the determination of bisphenol A (BPA). Under the optimal conditions, the oxidation peak current increased linearly with the concentration of BPA in the range of 5.0×10(-8) to 4.0×10(-6)M with correlation coefficient 0.998 and limits of detection 2.0×10(-8)M. Due to high absorption nature for BPA and electron deficiency on ZnTsPc/f-GN, it presented the unique electron pathway arising from π-π stackable interaction during redox process for detecting BPA. The sensor exhibited remarkable long-term stability, good anti-interference and excellent electrocatalytic activity towards BPA detection.


Assuntos
Compostos Benzidrílicos/química , Grafite/química , Indóis/química , Nanocompostos/química , Compostos Organometálicos/química , Fenóis/química , Técnicas Biossensoriais/métodos , Carbono/química , Eletrodos , Elétrons , Limite de Detecção , Oxirredução , Eletricidade Estática
10.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(11): 3161-6, 2015 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-26978928

RESUMO

In this work, cadmium nitrate hexahydrate [Cd(NO3)2 · 6H2O] is as a source of cadmium, zinc nitrate [Zn(NO3)2] as a source of zinc source, and NaHSe as a source of selenium which was prepared through reducing the elemental selenium with sodium borohydride (NaBH4). Then water-soluble Cd1₋xZnxSe ternary quantum dots with different component were prepared by colloid chemistry. The as-prepared Cd1₋xZnx Se ternary quantum dots exhibit stable fluorescent property in aqueous solution, and can still maintain good dispersivity at room temperature for four months. Powder X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) were used to analyze crystal structure and morphology of the prepared Cd1₋xZnxSe. It is found that the as-prepared ternary quantum dots are cubic phase, show as sphere, and the average of particle size is approximate 4 nm. The spectral properties and energy band structure of the as-prepared ternary quantum dots were modulated through changing the atom ratio of elements Zn and Cd. Compared with binary quantum dots CdSe and ZnSe, the ultraviolet-visible (UV-Visible) absorption spectrum and fluorescence (FL) emission spectrum of ternary quantum dots are both red-shift. The composites (Cd0.5 Zn0.5 Se@TNTs) of Cd0.5 Zn0.5 Se ternary quantum dots and TiO2 nanotubes (TNTs) were prepared by directly immerging TNTs into quantum dots dispersive solution for 5 hours. TEM image shows that the Cd0.5 Zn0.5 Se ternary quantum dots were closely combined to nanotube surface. The infrared spectra show that the Ti-Se bond was formed between Cd0.5 Zn0.5 Se ternary quantum dots and TiO2 nanotubes, which improve the stability of the composite. Compared to pristine TNTs, UV-Visible absorption spectrum of the composites is significantly enhanced in the visible region of light. And the absorption band edge of Cd0.5Zn0.5 Se@TNTs red-shift from 400 to 700 nm. The recombination of the photogenerated electron-hole pairs was restrained with the as-prepared ternary quantum dots. Therefore, the visible-light photocatalytic efficiency was greatly improved. After visible-light irradiation for 60 min, the degradation of Cd0.5 Zn0.5 Se@TNTs photocatalysts for RhB is nearly 100%, which is about 3. 3 times of that of pristine TNTs and 2. 5 times of that of pure Cd0.5 Zn0.5 Se ternary quantum dots, respectively.

11.
Mater Sci Eng C Mater Biol Appl ; 39: 92-9, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24863203

RESUMO

In this study, we reported on a low detection limit penicillin biosensor with layer-by-layer (LbL) film containing single-graphene nanosheets (SGNs) preadsorbed with hematein, ionic liquids (ILs) and penicillinase. The penicillinase catalyzes the hydrolysis of penicillin to penicilloic acid, where H(+) is liberated and monitored amperometrically with hematein as a pH indicator. The SGN-hematein/ILs/penicillinase biosensor exhibited excellent performance for penicillin in PBS with a wide range from 1.25×10(-13) to 7.5×10(-3)M, and a low detection limit of 10(-13)M (0.04ppt, S/N≥3). Furthermore, the detection of penicillin concentration in real sample (milk) had acceptable accuracy with the assay system.


Assuntos
Técnicas Biossensoriais/métodos , Grafite/química , Hematoxilina/análogos & derivados , Líquidos Iônicos/química , Penicilinase/química , Penicilinas/análise , Eletroquímica , Eletrodos , Hematoxilina/química , Concentração de Íons de Hidrogênio , Hidrólise , Limite de Detecção , Ácido Penicilânico/análogos & derivados , Ácido Penicilânico/química
12.
Mater Sci Eng C Mater Biol Appl ; 38: 39-45, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24656350

RESUMO

Hexagonal Ag nanoplates (NPs) were synthesized by polyvinylpyrrolidone (PVP) and trisodium citrate (TSC) which selectively absorbed to Ag (100) and Ag (111) surfaces, then were anchored to graphene (GN) to form novel Ag NPs/GN composite. The thickness of Ag NPs is ~4 nm and the length is 18-66 nm. Transmission electron microscopy (TEM) image shows that the plates are f-c-c crystals containing {111} facets on their two planar surfaces. Zeta potential indicated that the surface of Ag NPs/GN is negatively charged while vanillin is positively charged. Thus Ag NPs/GN modified on glass carbon electrodes (GCE) allowed abundant adsorption for vanillin and electron transfer between vanillin and Ag NPs/GN/GCE. Square wave voltammetry (SWV) results indicated that the over potential on Ag NPs/GN/GCE negatively shifts 52 mV than that on Ag NPs/GCE. Ag NPs/GN with enhanced surface area and good conductivity exhibited an excellent electrocatalytic activity toward the oxidation of vanillin. The corresponding linear range was estimated to be from 2 to 100 µM (R(2)=0.998), and the detection limit is 3.32×10(-7) M (S/N=3). The as-prepared vanillin sensor exhibits good selectivity and potential application in practical vanillin determination.


Assuntos
Benzaldeídos/análise , Técnicas Eletroquímicas/métodos , Grafite/química , Nanopartículas Metálicas/química , Prata/química , Calibragem , Carbono/química , Fenômenos Químicos , Eletrodos , Vidro/química , Nanopartículas Metálicas/ultraestrutura , Microscopia de Força Atômica , Povidona/química , Espectrofotometria Ultravioleta
13.
Asian Pac J Cancer Prev ; 15(3): 1075-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24606421

RESUMO

MicroRNA expression is a research focus in studies of tumors. This article concentrates attention on potential links between tumors caused by mouse mammary tumor virus (MMTV) and human breast cancer, in order to provide theoretical basis for using mouse model to search for miRNA effects mediated by Wnt/beta-catenin signaling in human breast cancer. By analyzing interactions between miRNAs and the Wnt/beta-catenin signaling pathway in breast cancer, we hope to casts light on more biological functions of miRNAs in the process of tumor formation and growth and to explore their potential value in cancer diagnosis, prognosis and treatment. Our endeavor aimed at providing theoretical basis for finding safer, more effective methods for treatment of human breast cancer at the miRNA molecular level.


Assuntos
Neoplasias da Mama/genética , Vírus do Tumor Mamário do Camundongo/genética , MicroRNAs/genética , Via de Sinalização Wnt/genética , Animais , Neoplasias da Mama/epidemiologia , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , MicroRNAs/biossíntese , Infecções por Retroviridae/epidemiologia , Infecções Tumorais por Vírus/epidemiologia , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , beta Catenina/genética , beta Catenina/metabolismo
14.
Mater Sci Eng C Mater Biol Appl ; 34: 304-10, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24268262

RESUMO

In this paper, we reported a simple strategy for synthesizing well-defined TiO2NTs-Au@Pd hybrid nanostructures with prior TiO2 nanotube functionalization (F-TiO2NTs). TiO2NTs with larger surface area (BET surface area is 184.9m(2)g(-1)) were synthesized by hydrothermal method, and the NTs are anatase phase with a range of 2-3µm in length and 30-50nm in diameter after calcined at 400°C for 3h. 3-Aminopropyl-trimethoxysilane (APTMS) as a coupling agent was reacted with the surface hydroxyl groups as anchoring sites for flower-shaped bimetallic Au@Pd nanostructures, self-assembling amine functionality on the surface of TiO2NTs. Note that two faces at the interface between F-TiO2NTs with (004) plane and Au@Pd nanostructures with (111) one of cubic Au and Pd nanoparticles are compatible, benefiting to the charge transfer between two components due to their crystalline coordination. The results showed that as-prepared F-TiO2NTs-Au@Pd hybrid nanostructures modified glassy carbon electrode (GCE) exhibits high electrocatalytic activity toward hydrazine (N2H4) at low potential and a linear response from 0.06 to 700µM with the detection limit for N2H4 was found to be 1.2×10(-8)M (S/N=3). Based on scan rate effect during the hydrazine oxidation, it indicates that the number of electrons transferred in the rate-limiting step is 1, and a transfer coefficient (α) is estimated as 0.73. The self-assembled F-TiO2NTs-Au@Pd hybrid nanostructures as enhanced materials present excellent electrocatalytic activity, fast response, highly sensitive and have a promising application potential in nonenzymatic sensing.


Assuntos
Técnicas Eletroquímicas/instrumentação , Ouro/química , Hidrazinas/análise , Nanopartículas Metálicas/química , Nanotubos/química , Paládio/química , Titânio/química , Aminas/química , Carbono/química , Catálise , Eletrodos , Vidro/química , Nanopartículas Metálicas/ultraestrutura , Nanotubos/ultraestrutura , Oxirredução , Difração de Raios X
15.
Virol J ; 10: 109, 2013 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-23566727

RESUMO

BACKGROUND: Canine distemper virus (CDV) infects a variety of carnivores, including wild and domestic Canidae. In this study, we sequenced and phylogenetic analyses of the hemagglutinin (H) genes from eight canine distemper virus (CDV) isolates obtained from seven raccoon dogs (Nyctereutes procyonoides) and a giant panda (Ailuropoda melanoleuca) in China. RESULTS: Phylogenetic analysis of the partial hemagglutinin gene sequences showed close clustering for geographic lineages, clearly distinct from vaccine strains and other wild-type foreign CDV strains, all the CDV strains were characterized as Asia-1 genotype and were highly similar to each other (91.5-99.8% nt and 94.4-99.8% aa). The giant panda and raccoon dogs all were 549Y on the HA protein in this study, irrespective of the host species. CONCLUSIONS: These findings enhance our knowledge of the genetic characteristics of Chinese CDV isolates, and may facilitate the development of effective strategies for monitoring and controlling CDV for wild canids and non-canids in China.


Assuntos
Vírus da Cinomose Canina/classificação , Vírus da Cinomose Canina/genética , Hemaglutininas Virais/genética , Filogeografia , Guaxinins/virologia , Ursidae/virologia , Animais , China , Análise por Conglomerados , Vírus da Cinomose Canina/isolamento & purificação , Variação Genética , Dados de Sequência Molecular , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
16.
J Hazard Mater ; 217-218: 100-6, 2012 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-22459971

RESUMO

An oriented hierarchical ZnO flower-rod arrays (FRs) were prepared on indium doped tin oxide (ITO) glass using a facile solution-based method assisted with ZnO seed layer. And the as-prepared ZnO FRs/ITO was used as a convenient photocatalytic device that recycled without centrifugation. The results show that ZnO FRs are wurtzite phase with single crystalline grown along the [001] direction. The photoluminescence (PL) spectra illustrate that there are more oxygen vacancies on the surface of ZnO FRs compared with ZnO nanoparticles (NPs). The electrochemical methods using Rhodamine B (RhB) as electrolyte are also performed to study on the photodegradation mechanism where RhB is acted as photocatalytic substrate. For ZnO FRs, the higher photoinduced currents under UV irradiation and current density prove that the recombination of electron-hole pairs is restrained with oxygen vacancies, and the lower charge transfer resistance suggest that the charges could move quickly through ZnO oriented structures. Therefore, the photocatalytic activity is enhanced by ZnO FRs compared with ZnO NPs, and RhB degradation efficiency of ZnO FRs photocatalysts is nearly 100% by UV irradiation for 1.5h.


Assuntos
Óxido de Zinco/química , Catálise , Microscopia Eletrônica de Varredura , Processos Fotoquímicos , Espectrofotometria Ultravioleta
17.
Bioresour Technol ; 100(23): 6129-32, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19640700

RESUMO

A novel gene, EG encoding enzymes involved in carboxymethyl cellulose (CMC) degradation was isolated, sequenced from the filamentous fungus Rhizopus stolonifer var. reflexus TP-02, and expressed in Escherichia coli BL21. The results showed that the gene amplified from the cDNA of the strain could be classified as the family of endoglucanase. During the fermentation process, the maximum endoglucanase activity (i.e. 0.715 IU/ml) of the recombinant bacteria was obtained at 36 h. The SDS-PAGE analysis on purified samples showed that a band with apparent molecular weight of about 40 kDa was detected after staining with Coomassie brilliant blue.


Assuntos
Celulase/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Rhizopus/enzimologia , Rhizopus/genética , Carboximetilcelulose Sódica/química , Carboximetilcelulose Sódica/metabolismo , Celulase/química , DNA Complementar/metabolismo , Eletroforese em Gel de Poliacrilamida , Fermentação , Regulação da Expressão Gênica , Vetores Genéticos , Filogenia , RNA Mensageiro/metabolismo , Fatores de Tempo
18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 27(11): 2329-32, 2007 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-18260424

RESUMO

Tetrasulfophthalocyaninatozinc/titanium dioxide (ZnTsPc/TiO2) was synthesized by a novel in-situ and self-assembly process. The prepared products, including pure TiO2 and ZnTsPc, were characterized by XRD, UV-Vis, FTIR, Zeta potential and fluorescence spectroscopic techniques. The results indicated that ZnTsPc was indeed synthesized during the in-situ method and sol-gel process. A chemical bond (--SO2--O--Ti--) was also formed between the sensitizer (ZnTsPc) and the surface of titanium dioxide particles. The photocatalyst of ZnTsPc/TiO2 reveals greatly enhanced activity for the degradation of organic pollutant, Rhodamine B, under visible-light irradiation as compared with pure TiO2 and P25. The sensitization mechanism is that photo-generated charge carriers are separated by the chemical bond between ZnTsPc and TiO2.

19.
Guang Pu Xue Yu Guang Pu Fen Xi ; 26(11): 2061-4, 2006 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-17260757

RESUMO

The meso-tetraphenylporphyrinatozinc/titanium dioxide (ZnTPP/TiO2) nanocompounds with different molar ratios were synthesized by sol-gel method at 400 degrees C, 4h. The nanocompounds were characterized by XRD, UV-Vis, FTIR and Fluorescence methods. Anatase for TiO2 in the nanocompounds was defined, and ZnTPP was also obtained during in-situ process. Photocatalystic activities of them influenced by the proportion between ZnTPP and TiO2 were discussed under visible light. The results show that a nanocompound (ZnTPP:TiO2 = 1:100 mol%) has the best photocatalystic activity, and the degradation of Rhodanmine B is up to 92% after 150 minutes under visible light irradiation. The sensitization mechanism is that the photogenerated charge carriers are separated by Zn--O bond between ZnTPP and TiO2.

20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 24(3): 261-5, 2004 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-15759970

RESUMO

In this paper, the nano-sized SO4(2-)/TiO2 solid superacid photocatalysts have been prepared by the method of hydrothermal heating the mixed solution of Ti(S04)2 and urea, heating-decomposing, wet impregnating-calcining. The middle products and the ultimate products have been characterized by XRD, BET, FTIR, DRS and FS. The degradation of rhodamine B by photocatalyst was regarded as a model reaction. The optimum condition of preparing SO4(2-)/TiO2 photocatalysts has been chosen. The results show that hydrothermal treating the solution of Ti(SO4)2 can get the anatase nano-sized TiO2 in the weak alkalinity medium; at 300 degrees C by-products of hydrothermal reaction, such as (NH4)2SO4 and so on, can be decomposed by calcining for 4 hours, avoiding much loss of H2SO4; the most important factors that influence the photocatalystic activities of SO4(2-)/TiO2 are the concentration of SO4(2-) on TiO2 and the calcination time. SO4(2-)/TiO2 photocatalysts have the best photocatalystic activities, up to the level of P-25 photocatalyst, when the concentration of SO4(2-) on TiO2 is 11% and the calcination temperature is 450 degrees C.

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