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1.
J Biotechnol ; 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31726082

RESUMO

Catalytic transformation of biomass-derived furans into value-added chemicals and biofuels has received considerable interest recently. In this work, aldehyde dehydrogenases (ALDHs) were identified from Comamonas testosteroni SC1588 for the oxidation of bio-based furans into furan carboxylic acids. Of the whole-cell biocatalysts constructed, Escherichia coli expressing a vanillin dehydrogenase (E. coli_CtVDH1) proved to be the best for the oxidation of 5-hydroxymethylfurfural (HMF). 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA) was obtained in the yield of approximately 92% within 12 h using this recombinant strain when the HMF concentration was up to 200 mM. In a fed-batch process, 292 mM of HMFCA was produced within 20.5 h, thereby providing a productivity as high as 2.0 g/L h. Other furan carboxylic acids were synthesized in the yields of 83-95%. Besides, the partially purified HMF was smoothly converted into HMFCA by this recombinant strain, with a 90% yield.

2.
J Agric Food Chem ; 67(33): 9382-9389, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31361959

RESUMO

Early stage exposure of foodborne substances, such as brightening agent titanium dioxide nanoparticles (TiO2 NPs), can cause long-term effects in adulthood. We aimed to explore the potential adverse effect of long-term dietary intake of TiO2 NPs. After feeding for 2-3 months from weaning, TiO2 NPs-exposed mice showed lower body weight and induced intestinal inflammation. However, this phenomenon was not observed in gut microbiota-removed mice. TiO2 NPs exposure rarely affected the diversity of microbial communities, but significantly decreased the abundance of several probiotic taxa including Bifidobacterium and Lactobacillus. Additionally, TiO2 NPs aggravated DSS-induced chronic colitis and immune response in vivo, and reduced the population of CD4+T cells, regulatory T cells, and macrophages in mesenteric lymph nodes. Therefore, dietary TiO2 NPs could interfere with the balance of immune system and dynamic of gut microbiome, which may result in low-grade intestinal inflammation and aggravated immunological response to external stimulus, thus introducing potential health risk.


Assuntos
Intestinos/efeitos dos fármacos , Intestinos/imunologia , Nanopartículas/metabolismo , Nanopartículas/toxicidade , Titânio/metabolismo , Titânio/toxicidade , Animais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Peso Corporal/efeitos dos fármacos , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/microbiologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Fatores de Tempo
3.
J Mol Cell Biol ; 9(3): 209-219, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28510697

RESUMO

Extraribosomal functions of ribosomal proteins (RPs) have gained much attention for their implications in tumorigenesis and progression. However, the regulations for transition between the ribosomal and extraribosomal functions of RPs are rarely reported. Herein, we identified a ribosomal protein S7-interacting partner, BCCIPß, which modulates the functional conversion of S7. Through the N-terminal acidic domain, BCCIPß interacts with the central basic region in S7 and regulates the extraribosomal distribution of S7. BCCIPß deficiency abrogates the ribosomal accumulation but enhances the ribosome-free location of S7. This translocation further impairs protein synthesis and triggers ribosomal stress. Consequently, BCCIPß deficiency suppresses the ribosomal function and initiates the extraribosomal function of S7, resulting in restriction of cell proliferation. Moreover, clinically relevant S7 mutations were found to dampen the interaction with BCCIPß and facilitate the functional transition of S7. In conclusion, BCCIPß, as a S7 modulator, contributes to the regulation of ribosomal and extraribosomal functions of S7 and has implications in cell growth and tumor development.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Sítios de Ligação , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Células HEK293 , Humanos , Imunoprecipitação , Mutação , Neoplasias , Proteínas Nucleares/química , Proteínas Nucleares/genética , Mapeamento de Interação de Proteínas , Proteínas Ribossômicas/química , Ribossomos/metabolismo , Transdução de Sinais , Eletricidade Estática , Proteína Supressora de Tumor p53/metabolismo
4.
Toxicol Res (Camb) ; 5(1): 107-115, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30090330

RESUMO

Benzo(a)pyrene (B[a]P) is a common environmental and foodborne pollutant which has been identified as a Group I carcinogen. Although the carcinogenicity of B[a]P has been illustrated, its comprehensive influence on metabolism and further relevance in adverse health outcomes are not well understood. To investigate the global metabolic effects of long-term B[a]P exposure at environmental dosage, we utilized the human SMMC-7721 cell-based B[a]P exposure models to perform a metabolomics study and network analysis. A total of 316 biochemicals were identified and 104 metabolites were found to be significantly altered. Bioinformatics analysis showed that the amino acid, carbohydrate, and lipid metabolism pathways and the nucleotide metabolism pathway were influenced by prolonged B[a]P exposure. Notably, the metabolic effects of B[a]P varied with different dosages. In addition, B[a]P exposure caused a decline in the glycolysis process but enhanced the glycolytic capability of SMMC-7721 cells in vitro. These findings establish the overall B[a]P-induced metabolic network, characterize the metabolic effects of chronic and environmental B[a]P exposure on human-relevant cells, and enhance the understanding of the adverse outcome pathway frame of B[a]P.

5.
Opt Lett ; 38(22): 4849-52, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24322148

RESUMO

Free carrier absorption (FCA) in silicon is the major obstacle toward achieving optical gain in Si nanostructure systems. In this Letter, we present experimental results of pump-induced loss for TE and TM polarization in multislot SiO2/nc-Si waveguides. Continuous wavelength and ultrafast studies of carriers excited in the nc-Si multilayers reveal strong suppression of transmission loss related to FCA in Si nanostructures for TM-polarized probe light. We demonstrate theoretically and experimentally that FCA may be reduced under TM polarization as much as 9 times compared to TE polarization.


Assuntos
Nanopartículas/química , Dióxido de Silício/química , Silício/química , Ressonância de Plasmônio de Superfície/instrumentação , Absorção , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Teste de Materiais , Nanopartículas/ultraestrutura , Espalhamento de Radiação
6.
Opt Express ; 16(12): 8623-8, 2008 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-18545575

RESUMO

Through simulations and measurements, we show that in multi-slot thin film waveguides, the TM polarized modes can be confined mostly in the low refractive index layers of the waveguide. The structure consisted of alternating layers of a-Si and SiO(2), in the thickness range between 3 and 40 nm, for which the slots were the SiO(2) layers. Simulations were performed using the transfer matrix method and experiments using the m-line technique at 1.55 mum. The dependence of the birefringence and of the power confinement in the slots was studied as a function of the waveguide thickness, the Si and SiO(2) layer thicknesses, and the SiO(2) / Si layer thickness ratio. We find a large birefringence-a refractive index difference between TE and TM modes-as large as 0.8. For TM polarized modes, up to ~ 85% of the total power in the fundamental mode can be confined in the slots.


Assuntos
Modelos Teóricos , Óptica e Fotônica/instrumentação , Refratometria/instrumentação , Dióxido de Silício/química , Silício/química , Transdutores , Birrefringência , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Refratometria/métodos , Espalhamento de Radiação
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