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1.
Cell Biol Toxicol ; 39(6): 3197-3217, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37603122

RESUMO

Wnt signaling is a principal pathway regulating the essential activities of cell proliferation. Here, we investigated the effect of Wnt/ß-catenin signaling on in vivo drug-induced renal injury through the deletion of Dact2, a Wnt antagonist, and deciphered the underlying mechanism. Wild-type (WT) and Dact2 knockout (KO) mice were administered a single intraperitoneal injection of cisplatin to induce renal injury. The injury was alleviated in Dact2 KO mice, which showed lower levels of blood urea nitrogen and creatinine. RNA sequencing revealed 194 differentially expressed genes (DEGs) between WT and Dact2 KO mouse kidney before cisplatin treatment. Among them, higher levels of Igf1, one of the Wnt target genes responsible for "Positive regulation of cell proliferation" in KO mice, were confirmed along with the induction of Ki67 expression. In RNA-seq analysis comparing WT and Dact2 KO mice after cisplatin treatment, genes related to "Apoptosis" and "Activation of mitogen-activated protein kinase (MAPK) activity" were among the downregulated DEGs in KO mice. These results were corroborated in western blotting of proteins related to apoptosis and proapoptotic MAPK pathway; the expression of which was found to be lower in cisplatin-treated KO mice. Importantly, ß-catenin was found to directly bind to and regulate the transcription of Igf1, leading to the alleviation of cisplatin-induced cytotoxicity by the Wnt agonist, CHIR-99021. In addition, Igf1 knockdown accelerated cisplatin-induced cytotoxicity, accompanied by the MAPK upregulation. Our findings suggest that Dact2 knockout could protect cisplatin-induced nephrotoxicity by inhibiting apoptosis, possibly through the regulation of the Igf1-MAPK axis associated with Wnt/ß-catenin signaling.


Assuntos
Cisplatino , beta Catenina , Camundongos , Animais , Cisplatino/farmacologia , beta Catenina/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Via de Sinalização Wnt , Apoptose
2.
Int J Mol Sci ; 24(4)2023 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-36834930

RESUMO

Obesity-induced inflammation and insulin resistance are mediated by macrophage infiltration into adipose tissue. We investigated the effects of 7,8-dihydroxyflavone (7,8-DHF), a flavone found in plants, on the inflammatory response and insulin resistance induced by the interaction between adipocytes and macrophages. Hypertrophied 3T3-L1 adipocytes were cocultured with RAW 264.7 macrophages and treated with 7,8-DHF (3.12, 12.5, and 50 µM). The inflammatory cytokines and free fatty acid (FFA) release were evaluated by assay kits, and signaling pathways were determined by immunoblotting. Coculture of adipocytes and macrophages increased inflammatory mediators, such as nitric oxide (NO), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) and FFA secretion but suppressed the production of anti-inflammatory adiponectin. 7,8-DHF counteracted the coculture-induced changes (p < 0.001). 7,8-DHF also inhibited c-Jun N-terminal kinase (JNK) activation and blocked nuclear factor kappa B (NF-κB) nuclear translocation in the coculture system (p < 0.01). In addition, adipocytes cocultured with macrophages did not increase glucose uptake and Akt phosphorylation in response to insulin. However, 7,8-DHF treatment recovered the impaired responsiveness to insulin (p < 0.01). These findings show that 7,8-DHF alleviates inflammation and adipocyte dysfunction in the coculture of hypertrophied 3T3-L1 adipocytes and RAW 264.7 macrophages, indicating its potential as a therapeutic agent for obesity-induced insulin resistance.


Assuntos
Adipócitos , Flavonas , Inflamação , Resistência à Insulina , Macrófagos , Animais , Camundongos , Células 3T3-L1 , Adipócitos/metabolismo , Técnicas de Cocultura , Inflamação/metabolismo , Insulina/metabolismo , Macrófagos/metabolismo , Obesidade/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Flavonas/metabolismo , Flavonas/farmacologia , Comunicação Parácrina
3.
Bioconjug Chem ; 31(3): 923-932, 2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-32027493

RESUMO

Nonsmall cell lung cancer (NSCLC) is a leading cause of global cancer mortality. Recently, combinatorial treatment approaches have shown promise as they better address tumor heterogeneity. However, drug pharmacokinetics and tissue distribution differences remain problematic. To overcome these issues and improve therapeutic efficacies, the use of nanomedicines has been suggested. We devised a CD44 receptor target hyaluronic acid (HA)-decorated glycol chitosan (GC) nanoparticle which is conjugated to doxorubicin (DOX) by a pH-sensitive linker and coloaded celecoxib (CXB; HA-GC-DOX/CXB). Successful chemical conjugation of GC to DOX was confirmed and HA-GC-DOX/CXB showed ∼150 nm of uniform spherical shape. HA-GC-DOX/CXB were stable at pH 7.4 but steadily increased in size and released drugs at pH 6.0 and 4.0. In vitro NSCLC cells showed that DOX and CXB combination therapy has synergism in both free drug and nanoparticle formulation. In vivo NSCLC xenograft mice showed DOX and CXB exhibited a synergistic tumor suppressive effect in HA-GC-DOX/CXB. Furthermore, HA-GC-DOX/CXB dramatically inhibited tumor growth compared to other treatments as well as suppressed inflammation and metastasis-related gene/protein in the tumor tissues. Our findings demonstrate HA-GC-DOX/CXB is a potential anticancer therapy that controlled release under acidic tumor microenvironments and enhanced CD44 overexpressed tumor target efficacy.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/patologia , Celecoxib/química , Quitosana/química , Doxorrubicina/química , Ácido Hialurônico/química , Neoplasias Pulmonares/patologia , Nanopartículas/química , Células A549 , Animais , Transporte Biológico , Celecoxib/metabolismo , Celecoxib/farmacologia , Preparações de Ação Retardada , Doxorrubicina/metabolismo , Doxorrubicina/farmacologia , Portadores de Fármacos/química , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Bioconjug Chem ; 31(3): 803-812, 2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-32069035

RESUMO

Lung cancer is diagnosed at an advanced stage due to its unrecognized symptoms, resulting in high mortality. In recent decades, research into the development of an early diagnostic method for lung cancer has expanded in order to overcome the high mortality rate. Calpain 2 (CAPN2) has been suggested as a tumor marker linked to angiogenesis, cell proliferation, and migration in non-small cell lung cancer. In this study, CAPN2 enzyme-activatable near-infrared peptide sensor linked to human serum albumin (HSA-CAPN2) was developed. Intracellular localization and strong recovered fluorescence signals of HSA-CAPN2 were observed in in vitro experiments using A549-Luc cells, and signal recovery was inhibited by ALLN (a CAPN2 inhibitor). In vivo distribution and signal recovery evaluations performed using A549-Luc cell xenograft mice revealed that HSA-CAPN2 accumulated in the tumor region and produced high fluorescent signal recovery. Three-dimensional reconstructed images using single-plane illumination microscopy after tissue clarity visualized localization of HSA-CAPN2 in tumors. In addition, ALLN pretreatment showed a significant inhibitory effect on signal recovery of HSA-CAPN2, and that inhibition was induced by downregulation of CAPN2 at the gene and protein levels followed by decreases in Ca2+ levels. Overall, the results demonstrate the potential of HSA-CAPN2 as a sensor for CAPN2-enriched cancer.


Assuntos
Técnicas Biossensoriais/métodos , Calpaína/metabolismo , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Detecção Precoce de Câncer , Neoplasias Pulmonares/diagnóstico , Nanotecnologia/métodos , Albumina Sérica Humana/metabolismo , Células A549 , Animais , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Transformação Celular Neoplásica , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Camundongos , Imagem Óptica
5.
J Ind Microbiol Biotechnol ; 47(6-7): 537-542, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32588231

RESUMO

Alizarin has been reported to have an antigenotoxic activity along with an inhibitory effect on the tumor cell growth of human colon carcinoma cells. Alizarin was biotransformed into an O-methoxide derivative using O-methyltransferase from Streptomyces avermitilis MA4680 (SaOMT2) to enhance its bioefficacy. The biotransformed product was extracted, purified, and characterized using various chromatographic and spectroscopic analyses, and confirmed to be an alizarin 2-O-methoxide. The antiproliferative activity of the compound against gastric cancer cells (AGS), uterine cervical cancer (Hela), liver cancer (HepG2), and normal cell lines was investigated. Alizarin 2-O-methoxide showed an inhibitory effect on all three cancer-cell lines at very low concentrations, from 0.078 µM, with no cytotoxicity against 267B1 (human prostate epithelial) and MRC-5 (normal human fetal lung fibroblast).


Assuntos
Antraquinonas/metabolismo , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Neoplasias/patologia , Streptomyces/enzimologia , Biotransformação , Linhagem Celular Tumoral , Escherichia coli , Células HeLa , Células Hep G2 , Humanos , Microbiologia Industrial , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Neoplasias/tratamento farmacológico
6.
Molecules ; 24(14)2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31311182

RESUMO

The very well-known bioactive natural product, resveratrol (3,5,4'-trihydroxystilbene), is a highly studied secondary metabolite produced by several plants, particularly grapes, passion fruit, white tea, and berries. It is in high demand not only because of its wide range of biological activities against various kinds of cardiovascular and nerve-related diseases, but also as important ingredients in pharmaceuticals and nutritional supplements. Due to its very low content in plants, multi-step isolation and purification processes, and environmental and chemical hazards issues, resveratrol extraction from plants is difficult, time consuming, impracticable, and unsustainable. Therefore, microbial hosts, such as Escherichia coli, Saccharomyces cerevisiae, and Corynebacterium glutamicum, are commonly used as an alternative production source by improvising resveratrol biosynthetic genes in them. The biosynthesis genes are rewired applying combinatorial biosynthetic systems, including metabolic engineering and synthetic biology, while optimizing the various production processes. The native biosynthesis of resveratrol is not present in microbes, which are easy to manipulate genetically, so the use of microbial hosts is increasing these days. This review will mainly focus on the recent biotechnological advances for the production of resveratrol, including the various strategies used to produce its chemically diverse derivatives.


Assuntos
Engenharia Metabólica/métodos , Proteínas de Plantas/genética , Plantas/química , Resveratrol/metabolismo , Vias Biossintéticas , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/crescimento & desenvolvimento , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Estrutura Molecular , Plantas/genética , Resveratrol/química , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Biologia Sintética
7.
Molecules ; 23(9)2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-30154376

RESUMO

Anthraquinones, naturally occurring bioactive compounds, have been reported to exhibit various biological activities, including anti-inflammatory, antiviral, antimicrobial, and anticancer effects. In this study, we biotransformed three selected anthraquinones into their novel O-glucoside derivatives, expressing a versatile glycosyltransferase (YjiC) from Bacillus licheniformis DSM 13 in Escherichia coli. Anthraflavic acid, alizarin, and 2-amino-3-hydroxyanthraquinone were exogenously fed to recombinant E. coli as substrate for biotransformation. The products anthraflavic acid-O-glucoside, alizarin 2-O-ß-d-glucoside, and 2-amino-3-O-glucosyl anthraquinone produced in the culture broths were characterized by various chromatographic and spectroscopic analyses. The comparative anti-proliferative assay against various cancer cells (gastric cancer-AGS, uterine cervical cancer-HeLa, and liver cancer-HepG2) were remarkable, since the synthesized glucoside compounds showed more than 60% of cell growth inhibition at concentrations ranging from ~50 µM to 100 µM. Importantly, one of the synthesized glucoside derivatives, alizarin 2-O-glucoside inhibited more than 90% of cell growth in all the cancer cell lines tested.


Assuntos
Antraquinonas/química , Antraquinonas/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Glucosídeos/química , Glucosídeos/farmacologia , Antraquinonas/metabolismo , Antineoplásicos/metabolismo , Bactérias/metabolismo , Vias Biossintéticas , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Glucosídeos/biossíntese , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas
8.
Bioconjug Chem ; 28(1): 115-123, 2017 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-27982578

RESUMO

Several types of nanoparticle-based imaging probes have been developed to replace conventional luminescent probes. For luminescence imaging, near-infrared (NIR) probes are useful in that they allow deep tissue penetration and high spatial resolution as a result of reduced light absorption/scattering and negligible autofluorescence in biological media. They rely on either an anti-Stokes or a Stokes shift process to generate luminescence. For example, transition metal-doped semiconductor nanoparticles and lanthanide-doped inorganic nanoparticles have been demonstrated as anti-Stokes shift-based agents that absorb NIR light through two- or three-photon absorption process and upconversion process, respectively. On the other hand, quantum dots (QDs) and lanthanide-doped nanoparticles that emit in NIR-II range (∼1000 to ∼1350 nm) were suggested as promising Stokes shift-based imaging agents. In this topical review, we summarize and discuss the recent progress in the development of inorganic nanoparticle-based luminescence imaging probes working in NIR range.


Assuntos
Compostos Inorgânicos/química , Elementos da Série dos Lantanídeos/química , Nanopartículas/química , Semicondutores , Espectroscopia de Luz Próxima ao Infravermelho
9.
Bioconjug Chem ; 28(1): 33-37, 2017 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-27792877

RESUMO

The use of inorganic nanoparticles (NPs) for biosensing requires that they exhibit high colloidal stability under various physiological conditions. Here, we report on a general approach to render hydrophobic NPs into hydrophilic ones that are ready for bioconjugation. The method uses peglyated polymers conjugated with multiple dopamines, which results in multidentate coordination. As proof-of-concept, we applied the coating to stabilize ferrite and lanthanide NPs synthesized by thermal decomposition. Both polymer-coated NPs showed excellent water solubility and were stable at high salt concentrations under physiological conditions. We used these NPs as molecular-sensing agents to detect exosomes and bacterial nucleic acids.


Assuntos
Técnicas Biossensoriais , Compostos Inorgânicos/química , Nanopartículas/química , Interações Hidrofóbicas e Hidrofílicas
10.
J Ind Microbiol Biotechnol ; 43(9): 1323-31, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27387419

RESUMO

Curdlan is a commercial polysaccharide made by fermentation of Agrobacterium sp. Its anticipated expansion to larger volume markets demands improvement in its production efficiency. Metabolic engineering for strain improvement has so far been limited due to the lack of genetic tools. This research aimed to identify strong promoters and to engineer a strain that converts cellobiose efficiently to curdlan. Three strong promoters were identified and were used to install an energy-efficient cellobiose phosphorolysis mechanism in a curdlan-producing strain. The engineered strains were shown with enhanced ability to utilize cellobiose, resulting in a 2.5-fold increase in titer. The availability of metabolically engineered strain capable of producing ß-glucan from cellobiose paves the way for its production from cellulose. The identified native promoters from Agrobacterium open up opportunities for further metabolic engineering for improved production of curdlan and other products. The success shown here marks the first such metabolic engineering effort in this microbe.


Assuntos
Agrobacterium/genética , Agrobacterium/metabolismo , Celobiose/metabolismo , beta-Glucanas/metabolismo , Fermentação , Engenharia Metabólica , Regiões Promotoras Genéticas
11.
Chem Soc Rev ; 44(6): 1302-17, 2015 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-25042637

RESUMO

Lanthanide-doped upconverting nanoparticles (UCNPs) have recently attracted enormous attention in the field of biological imaging owing to their unique optical properties: (1) efficient upconversion photoluminescence, which is intense enough to be detected at the single-particle level with a (nonscanning) wide-field microscope setup equipped with a continuous wave (CW) near-infrared (NIR) laser (980 nm), and (2) resistance to photoblinking and photobleaching. Moreover, the use of NIR excitation minimizes adverse photoinduced effects such as cellular photodamage and the autofluorescence background. Finally, the cytotoxicity of UCNPs is much lower than that of other nanoparticle systems. All these advantages can be exploited simultaneously without any conflicts, which enables the establishment of a novel UCNP-based platform for wide-field two-photon microscopy. UCNPs are also useful for multimodal in vivo imaging because simple variations in the composition of the lattice atoms and dopant ions integrated into the particles can be easily implemented, yielding various distinct biomedical activities relevant to magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET). These multiple functions embedded in a single type of UCNPs play a crucial role in precise disease diagnosis. The application of UCNPs is extended to therapeutic fields such as photodynamic and photothermal cancer therapies through advanced surface conjugation schemes.


Assuntos
Nanopartículas/química , Animais , Meios de Contraste/química , Humanos , Elementos da Série dos Lantanídeos/química , Imageamento por Ressonância Magnética , Microscopia de Fluorescência , Neoplasias/diagnóstico , Fótons , Tomografia por Emissão de Pósitrons , Espectroscopia de Luz Próxima ao Infravermelho , Tomografia Computadorizada por Raios X
12.
Bioconjug Chem ; 26(8): 1470-4, 2015 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-26102604

RESUMO

Star-shaped Au nanoparticles (Au nanostars, AuNS) have been developed to improve the plasmonic sensitivity, but their application has largely been limited to single-particle probes. We herein describe a AuNS clustering assay based on nanoscale self-assembly of multiple AuNS and which further increases detection sensitivity. We show that each cluster contains multiple nanogaps to concentrate electric fields, thereby amplifying the signal via plasmon coupling. Numerical simulation indicated that AuNS clusters assume up to 460-fold higher field density than Au nanosphere clusters of similar mass. The results were validated in model assays of protein biomarker detection. The AuNS clustering assay showed higher sensitivity than Au nanosphere. Minimizing the size of affinity ligand was found important to tightly confine electric fields and improve the sensitivity. The resulting assay is simple and fast and can be readily applied to point-of-care molecular detection schemes.


Assuntos
Bioensaio/métodos , Técnicas Biossensoriais/métodos , Ouro/química , Nanopartículas Metálicas/química , Nanoestruturas/química , Proteínas/análise , Campos Eletromagnéticos , Humanos , Imagem Molecular , Sondas Moleculares
13.
Mar Drugs ; 13(7): 4398-417, 2015 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-26193285

RESUMO

The Search for enzyme activities that efficiently degrade marine polysaccharides is becoming an increasingly important area for both structural analysis and production of lower-molecular weight oligosaccharides. In this study, an endo-acting fucoidanase that degrades Miyeokgui fucoidan (MF), a sulfated galactofucan isolated from the sporophyll (called Miyeokgui in Korean) of Undaria pinnatifida, into smaller-sized galactofuco-oligosaccharides (1000-4000 Da) was purified from a marine bacterium, Sphingomonas paucimobilis PF-1, by ammonium sulfate precipitation, diethylaminoethyl (DEAE)-Sepharose column chromatography, and chromatofocusing. The specific activity of this enzyme was approximately 112-fold higher than that of the crude enzyme, and its molecular weight was approximately 130 kDa (FNase S), as determined by native gel electrophoresis and 130 (S1), 70 (S2) and 60 (S3) kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature of FNase S were pH 6.0-7.0 and 40-45 °C, respectively. FNase S activity was enhanced by Mn2+ and Na+ (115.7% and 131.2%), but it was inhibited by Ca2+, K+, Ba2+, Cu2+ (96%, 83.7%, 84.3%, and 89.3%, respectively), each at 1 mM. The Km, Vmax and Kcat values of FNase S on MF were 1.7 mM, 0.62 mg·min-1, and 0.38·S-1, respectively. This enzyme could be a valuable tool for the structural analysis of fucoidans and production of bioactive fuco-oligosaccharides.


Assuntos
Glicosídeo Hidrolases/isolamento & purificação , Sphingomonas/enzimologia , Organismos Aquáticos/enzimologia , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Polissacarídeos/metabolismo , Especificidade por Substrato
14.
Biochem Biophys Res Commun ; 449(4): 438-43, 2014 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-24853804

RESUMO

Due to some severe side effects or lack of efficacy of currently used synthetic drugs, such as bisphosphonates (BPs), the search for new therapeutic agents that can more effectively prevent and treat osteoporosis (OP) has been an increasingly important topic of research. In this study, the low-molecular weight hyaluronan (LMW-HA, 50 kDa) produced by enzymatic degradation of high-molecular weight hyaluronan (HMW-HA, 1922 kDa) from Streptococcus zooepidemicus was evaluated in vitro for its anti-osteoclastogenic potentials using RAW 264.7 murine macrophage cells. LMW-HA (25-200 µg/ml) dose-dependently inhibited the receptor activator of NF-κB ligand (RANKL)-induced tartrate-resistance acid phosphatase (TRAP) activity and the formation of multinucleated osteoclasts. Western blot analysis showed that LMW-HA reduced the RANKL-induced expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), gelsolin and c-Src-proline-rich tyrosine kinase 2 suggesting that it could inhibit actin ring formation of osteoclast cells. In addition, LMW-HA inhibited the bone resorption activity of osteoclastic cells by dose-dependently attenuating the RANKL-induced expression of carbonic anhydrase II and integrin ß3. RT-PCR analysis showed that LMW-HA dose-dependently decreased the expression of osteoclast-specific genes, such as matrix metalloproteinase 9 (MMP-9) and cathepsin K, suggesting that it has potential to inhibit the differentiation of osteoclastic cells. Taken collectively, these results suggested that LMW-HA (50 kDa) has significant anti-osteoporotic activity in vitro and may be used as a potent functional ingredient in health beneficial foods or as a therapeutic agent to prevent or treat OP.


Assuntos
Ácido Hialurônico/farmacologia , Osteoporose/tratamento farmacológico , Fosfatase Ácida/metabolismo , Animais , Catepsina K/biossíntese , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Ácido Hialurônico/uso terapêutico , Isoenzimas/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Metaloproteinase 9 da Matriz/biossíntese , Camundongos , Peso Molecular , Osteoclastos/citologia , Osteoclastos/metabolismo , Ligante RANK/antagonistas & inibidores , Fator 6 Associado a Receptor de TNF/biossíntese , Fosfatase Ácida Resistente a Tartarato
15.
Nat Mater ; 12(4): 359-66, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23416726

RESUMO

Three-photon excitation is a process that occurs when three photons are simultaneously absorbed within a luminophore for photo-excitation through virtual states. Although the imaging application of this process was proposed decades ago, three-photon biomedical imaging has not been realized yet owing to its intrinsic low quantum efficiency. We herein report on high-resolution in vitro and in vivo imaging by combining three-photon excitation of ZnS nanocrystals and visible emission from Mn(2+) dopants. The large three-photon cross-section of the nanocrystals enabled targeted cellular imaging under high spatial resolution, approaching the theoretical limit of three-photon excitation. Owing to the enhanced Stokes shift achieved through nanocrystal doping, the three-photon process was successfully applied to high-resolution in vivo tumour-targeted imaging. Furthermore, the biocompatibility of ZnS nanocrystals offers great potential for clinical applications of three-photon imaging.


Assuntos
Nanopartículas/química , Sulfetos/química , Compostos de Zinco/química , Humanos , Manganês/química , Imagens de Fantasmas , Fótons , Células Tumorais Cultivadas
16.
Appl Environ Microbiol ; 80(23): 7235-43, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25239890

RESUMO

A UDP glucosyltransferase from Bacillus licheniformis was overexpressed, purified, and incubated with nucleotide diphosphate (NDP) d- and l-sugars to produce glucose, galactose, 2-deoxyglucose, viosamine, rhamnose, and fucose sugar-conjugated resveratrol glycosides. Significantly higher (90%) bioconversion of resveratrol was achieved with α-d-glucose as the sugar donor to produce four different glucosides of resveratrol: resveratrol 3-O-ß-d-glucoside, resveratrol 4'-O-ß-d-glucoside, resveratrol 3,5-O-ß-d-diglucoside, and resveratrol 3,5,4'-O-ß-d-triglucoside. The conversion rates and numbers of products formed were found to vary with the other NDP sugar donors. Resveratrol 3-O-ß-d-2-deoxyglucoside and resveratrol 3,5-O-ß-d-di-2-deoxyglucoside were found to be produced using TDP-2-deoxyglucose as a donor; however, the monoglycosides resveratrol 4'-O-ß-d-galactoside, resveratrol 4'-O-ß-d-viosaminoside, resveratrol 3-O-ß-l-rhamnoside, and resveratrol 3-O-ß-l-fucoside were produced from the respective sugar donors. Altogether, 10 diverse glycoside derivatives of the medically important resveratrol were generated, demonstrating the capacity of YjiC to produce structurally diverse resveratrol glycosides.


Assuntos
Bacillus/enzimologia , Glucuronosiltransferase/metabolismo , Glicosídeos/metabolismo , Estilbenos/metabolismo , Bacillus/genética , Carboidratos/análise , Clonagem Molecular , Citosol/química , Expressão Gênica , Glucuronosiltransferase/genética , Glucuronosiltransferase/isolamento & purificação , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Resveratrol
17.
Artigo em Inglês | MEDLINE | ID: mdl-38949109

RESUMO

There is a growing demand for research and development of advanced energy storage devices with high energy density utilizing earth-abundant metal anodes such as sodium metal. Tellurium, a member of the chalcogen group, stands out as a promising cathode material due to its remarkable volumetric capacity, comparable to sulfur, and significantly high electrical conductivity. However, critical issues arise from soluble sodium polytellurides, leading to the shuttle effect. This phenomenon can result in the loss of active materials, self-discharge, and anode instability. Here, we introduce polypyrrole-coated tellurium nanotubes as the cathode materials, where polypyrrole plays a crucial role in preventing the dissolution of polytellurides, as confirmed through operando optical microscopy. The polypyrrole-coated tellurium nanotubes exhibited an outstanding rate performance and long cycle stability in sodium-tellurium batteries. These research findings are anticipated to bolster the viability of polypyrrole-coated tellurium nanotubes as promising cathode materials, making a substantial contribution to the commercialization of sodium-ion battery technology.

18.
Chemosphere ; 352: 141233, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38266882

RESUMO

Hydrogen production from water splitting combined with renewable electricity can provide a viable solution to the energy crisis. A novel MoS2/NiS2/Ni3S4 heterostructure is designed as a bifunctional electrocatalyst by facile hydrothermal method to demonstrate excellent electrocatalytic performance towards overall water splitting applications. MoS2/NiS2/Ni3S4 heterostructure necessitates a low overpotential of 81 mV and 210 mV to attain a current density of 10 mA cm-2 during the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Consequently, the MoS2/NiS2/Ni3S4 heterostructure-based electrolyzer shows a low cell voltage of 1.54 V at 10 mA cm-2. The present work highlights the significance of the heterostructure configuration of transition metal sulfide-based electrocatalysts for electrochemical overall water splitting applications.


Assuntos
Eletricidade , Molibdênio , Hidrogênio , Oxigênio , Sulfetos
19.
J Colloid Interface Sci ; 663: 566-576, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38428114

RESUMO

Transition metal spinel oxides were engineered with active elements as bifunctional water splitting electrocatalysts to deliver superior intrinsic activity, stability, and improved conductivity to support green hydrogen production. In this study, we reported the ternary metal Ni-Fe-Co spinel oxide electrocatalysts prepared by defect engineering strategy with rich and deficient Na+ ions, termed NFCO-Na and NFCO, which suggest the formation of defects with Na+ forming tensile strain. The Na-rich NiFeCoO4 spinel oxide reveals lattice expansion, resulting in the formation of a defective crystal structure, suggesting higher electrocatalytic active sites. The spherical NFCO-Na electrocatalysts exhibit lower OER and HER overpotentials of 248 mV and 153 mV at 10 mA cm-2 and smaller Tafel slope values of about 78 mV dec-1 and 129 mV dec-1, respectively. Notably, the bifunctional NFCO-Na electrocatalyst requires a minimum cell voltage of about 1.67 V to drive a current density of 10 mA cm-2. The present work highlights the significant electrochemical activity of defect-engineered ternary metal oxides, which can be further upgraded as highly active electrocatalysts for water splitting applications.

20.
Appl Environ Microbiol ; 79(11): 3516-21, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23542617

RESUMO

A UDP-glycosyltransferase from Bacillus licheniformis was exploited for the glycosylation of phloretin. The in vitro glycosylation reaction confirmed the production of five phloretin glucosides, including three novel glucosides. Consequently, we demonstrated the application of the same glycosyltransferase for the efficient whole-cell biocatalysis of phloretin in engineered Escherichia coli.


Assuntos
Bacillus/enzimologia , Proteínas de Escherichia coli/metabolismo , Glicosiltransferases/metabolismo , Floretina/metabolismo , Cromatografia Líquida de Alta Pressão , Escherichia coli , Engenharia Genética , Glicosilação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Espectrometria de Massas em Tandem , Açúcares de Uridina Difosfato/metabolismo
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