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1.
J Enzyme Inhib Med Chem ; 36(1): 462-468, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33455472

RESUMO

To develop unique small-molecule inhibitors of hepatitis C virus (HCV), thiophen urea (TU) derivatives were synthesised and screened for HCV entry inhibitory activities. Among them, seven TU compounds exhibited portent anti-viral activities against genotypes 1/2 (EC50 < 30 nM) and subsequently, they were further investigated; based on the pharmacological, metabolic, pharmacokinetic, and safety profiles, J2H-1701 was selected as the optimised lead compound as an HCV entry inhibitor. J2H-1701 possesses effective multi-genotypic antiviral activity. The docking results suggested the potential interaction of J2H-1701 with the HCV E2 glycoprotein. These results suggest that J2H-1701 can be a potential candidate drug for the development of HCV entry inhibitors.


Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Tiofenos/farmacologia , Ureia/farmacologia , Antivirais/síntese química , Antivirais/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade , Tiofenos/síntese química , Tiofenos/química , Ureia/análogos & derivados , Ureia/química , Proteínas do Envelope Viral/antagonistas & inibidores , Proteínas do Envelope Viral/metabolismo , Internalização do Vírus/efeitos dos fármacos
2.
Sensors (Basel) ; 21(16)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34450817

RESUMO

Content-Centric Vehicular Networks (CCVNs) are considered as an attractive technology to efficiently distribute and share contents among vehicles in vehicular environments. Due to the large size of contents such as multimedia data, it might be difficult for a vehicle to download the whole of a content within the coverage of its current RoadSide Unit (RSU). To address this issue, many studies exploit mobility-based content precaching in the next RSU on the trajectory of the vehicle. To calculate the amount of the content precaching, they use a constant speed such as the current speed of the vehicle requesting the content or the average speed of vehicles in the next RSU. However, since they do not appropriately reflect the practical speed of the vehicle in the next RSU, they could incorrectly calculate the amount of the content precaching. Therefore, we propose an adaptive content precaching scheme (ACPS) that correctly estimates the predictive speed of a requester vehicle to reflect its practical speed and calculates the amount of the content precaching using its predictive speed. ACPS adjusts the predictive speed to the average speed starting from the current speed with the optimized adaptive value. To compensate for a subtle error between the predictive and the practical speeds, ACPS appropriately adds a guardband area to the precaching amount. Simulation results verify that ACPS achieves better performance than previous schemes with the current or the average speeds in terms of the content download delay and the backhaul traffic overhead.

3.
J Surg Oncol ; 115(8): 1011-1018, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28334428

RESUMO

INTRODUCTION: Accurate tumor-node-metastasis(TNM) staging of oral cavity cancer(OCC) is very important in the management of this dismal disease. However, stage migration from cTNM to pTNM was found in a portion of OCC patients. The objective of this study was to determine the possible causes of discrepancy between cTNM and pTNM in OCC and the clinical impacts of stage migration. METHODS: Clinical and pathological data of 252 OCC patients were retrospectively reviewed and compared each other. Clinical staging was determined through the multidisciplinary evaluation of pre-treatment work-ups including PET/CT. In addition, we compared the up-staged cases with those in the no-change group with the same pTNM stages to identify the clinical impacts of such change. RESULTS: Clinical staging yielded overall 82.5% diagnostic accuracy in predicting pathological tumor status, and tumor extent was under-estimated in 9.5-13.5% of cases. The main causes of T up-staging were under-estimation of surface dimension (62.5%) and deep invasion to tongue extrinsic muscles (37.5%). N up-staging was due to occult single (57.6%) and multiple (42.4%) metastases. Surprisingly, TNM up-staging in our series did not have prognostic significance under the current management protocol. CONCLUSION: Clinical under-estimation of pathological tumor extent occurred in approximately 13% of OCC, without clinical impacts on prognosis.


Assuntos
Carcinoma de Células Escamosas/patologia , Neoplasias Bucais/patologia , Estadiamento de Neoplasias , Adulto , Idoso , Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/mortalidade , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Neoplasias Bucais/diagnóstico por imagem , Neoplasias Bucais/mortalidade , Invasividade Neoplásica , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
4.
Nano Lett ; 16(11): 6746-6754, 2016 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-27704847

RESUMO

Atomically thin two-dimensional (2D) materials range from semimetallic graphene to insulating hexagonal boron nitride to semiconducting transition-metal dichalcogenides. Recently, metal-insulator-semiconductor field effect transistors built from these 2D elements were studied for flexible and transparent electronics. However, to induce ambipolar characteristics for alternative power-efficient circuitry, ion-gel gating is often employed for high capacitive coupling, limiting stable operation at ambient conditions. Here, we report reconfigurable MoTe2 optoelectronic transistors with all 2D components, where the device can be reconfigured by both drain and gate voltages. Eight different configurations for each fixed voltage are spatially resolved by scanning photocurrent microscopy. In addition, metal-insulator transitions are observed in both electron and hole carriers under 2 V due to strong Coulomb interaction in the system. Furthermore, the vertical tunneling photocurrent through multiple van der Waals layers between the gate and source contacts is measured. Our reconfigurable devices offer potential building blocks for system-on-a-chip optoelectronics.

5.
Phys Chem Chem Phys ; 16(7): 3087-94, 2014 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-24399098

RESUMO

One of the major challenges for the practical application of graphene is the large scale synthesis of uniform films with high quality at lower temperature. Here, we demonstrate the use of Ag-plated Cu substrates in the synthesis of high-quality graphene films via chemical vapor deposition (CVD) of methane gas at temperatures as low as 900 °C. Various experimental analyses show that the plated Ag diffuses into Cu to form a uniform Cu-Ag alloy that suppresses the formation of multilayer nucleation and decreases the activation energy of precursor formation, leading to a lower synthesis temperature with enhanced monolayer coverage. In addition, we also observed an unusual Ag-assisted abnormal grain growth of Cu into the cube texture with larger grain sizes and reduced grain boundaries, which is believed to provide the homogeneous environment needed for uniform graphene growth.

6.
Nat Nanotechnol ; 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38951597

RESUMO

The primary challenge facing silicon-based electronics, crucial for modern technological progress, is difficulty in dimensional scaling. This stems from a severe deterioration of transistor performance due to carrier scattering when silicon thickness is reduced below a few nanometres. Atomically thin two-dimensional (2D) semiconductors still maintain their electrical characteristics even at sub-nanometre scales and offer the potential for monolithic three-dimensional (3D) integration. Here we explore a strategic shift aimed at addressing the scaling bottleneck of silicon by adopting 2D semiconductors as new channel materials. Examining both academic and industrial viewpoints, we delve into the latest trends in channel materials, the integration of metal contacts and gate dielectrics, and offer insights into the emerging landscape of industrializing 2D semiconductor-based transistors for monolithic 3D integration.

7.
Phys Chem Chem Phys ; 15(15): 5379-85, 2013 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-23201966

RESUMO

A novel SERS-based sandwich immunoassay using DNA aptamers, silica-encapsulated hollow gold nanospheres (SEHGNs) and a gold-patterned microarray was developed for sensitive detection of VEGF (vascular endothelial growth factor) angiogenesis protein markers. Here, a DNA aptamer conjugated to SEHGN was used as a highly reproducible SERS-encoding nanoprobe, and a hybrid microarray including hydrophilic gold wells and other hydrophobic areas was used as a SERS substrate. Target specific DNA aptamers that fold into a G-quadruplex structure were used as a target recognition unit instead of VEGF antibodies. The detection sensitivity was increased by 2 or 3 orders of magnitude over the conventional ELISA method. In particular, the dynamic concentration range was 3 or 4 orders of magnitude greater than that of conventional ELISA. The results demonstrate that this sensing strategy using DNA aptamers is a powerful platform for the design of novel immune-sensors with high performance. In particular, SERS-based detection using SEHGNs provides great promise for highly sensitive biomarker sensing with unprecedented advantages.


Assuntos
Aptâmeros de Nucleotídeos/química , Ensaio de Imunoadsorção Enzimática , Ouro/química , Nanosferas/química , Dióxido de Silício/química , Fator A de Crescimento do Endotélio Vascular/análise , Biomarcadores Tumorais/análise , Quadruplex G , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Análise Espectral Raman
8.
J Clin Med ; 12(16)2023 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-37629284

RESUMO

Hangovers are uncomfortable physiological symptoms after alcohol consumption caused by acetaldehyde, a toxic substance in which alcohol is metabolized by alcohol dehydrogenase (ADH). Rapid alcohol and acetaldehyde decomposition are essential to alleviate alcohol handling symptoms. This study investigated the effects of HY_IPA combined with Mesembryanthemum crystallinum, Pueraria lobata flower, and Artemisia indica on alleviating hangovers. A randomized, double-blind, parallel-group, placebo-controlled clinical study was conducted on 80 individuals with hangover symptoms. Alcohol intake was 0.9 g/bw with 40% whiskey, adjusted proportionately to body weight. The Acute Hangover Scale total score was 5.24 ± 5.78 and 18.54 ± 18.50 in the HY_ IPA and placebo groups, respectively (p < 0.0001). All nine indicators of the hangover symptom questionnaire were significantly improved in the HY_IPA group (p < 0.01). Blood alcohol and acetaldehyde concentrations rapidly decreased from 30 min in the HY_IPA group (p < 0.05). ADH and acetaldehyde dehydrogenase (ALDH) activities in the blood of the HY_IPA group were significantly higher than those in the placebo group at 0, 1, and 2 h after alcohol consumption (p < 0.01). The rapid hangover relief was due to increased ADH and ALDH. Therefore, HY_IPA effectively relieves hangover symptoms by decomposing alcohol and acetaldehyde when consumed before alcohol consumption.

9.
Biomed Pharmacother ; 149: 112895, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35364379

RESUMO

In this study, the pharmacokinetic profiles of the bioactive components in the leaf extract of the medicinal herb, Cudrania tricuspidate, were investigated using an MS/MS-based molecular networking system. To identify the major active components of the C. tricuspidate leaf extract (CLE), HPLC-DAD analysis was conducted with a standard mixture of six flavonoids (rutin, isoquercitrin, nicotiflorin, kaempferol 3-O-glucoside, quercetin, and kaempferol). The unknown peaks were determined via molecular networking analysis using the mass dataset obtained by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). For the subsequent pharmacokinetic study, CLE (1 g/kg) was orally administered to rats, and plasma samples were collected. The product ion mass data of plasma samples using LC-QTOF/MS were obtained and subjected to molecular networking analysis. The resulting molecular networking map indicated that the glucuronide metabolites of quercetin and kaempferol were the major circulating species. Accordingly, quercetin and kaempferol were determined following ß-glucuronidase treatment, and their pharmacokinetic parameters were calculated. These findings indicate that the proposed molecular network-based approaches are potential and efficient methods for the pharmacokinetic study of herbal medicines.


Assuntos
Medicamentos de Ervas Chinesas , Moraceae , Plantas Medicinais , Animais , Cromatografia Líquida de Alta Pressão/métodos , Flavonoides/química , Quempferóis/química , Moraceae/química , Extratos Vegetais/química , Quercetina , Ratos , Espectrometria de Massas em Tandem/métodos
10.
Clin Exp Otorhinolaryngol ; 15(4): 346-353, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35835547

RESUMO

OBJECTIVES: Our previous study found that multilevel obstructive sleep apnea (OSA) surgery mitigated laryngopharyngeal reflux (LPR) symptoms in terms of the reflux symptom index (RSI), but no studies have investigated the impact of OSA surgery on laryngoscopic parameters. The aim of this study was to examine the clinical outcome of LPR improvement following OSA surgery, with a focus on both the RSI and the reflux finding score (RFS). METHODS: Prospectively collected data from 28 patients who underwent multilevel OSA surgery from 2017 to 2021 were retrospectively analyzed. Patients were asked to complete the RSI questionnaire and underwent a laryngoscopic examination to evaluate the RFS before and after surgery. Age, height, weight, body mass index (BMI), and polysomnography data before and after surgery were also reviewed. RESULTS: After surgery, the total RSI and RFS decreased significantly from 11.96±8.40 to 7.68±6.82 (P=0.003) and from 6.57±3.49 to 3.21±1.87 (P<0.001). The positive rates of RSI and RFS decreased from 28.6% to 17.9% and 32.1% to 0%, respectively. Significant improvements were found in the RSI subdomains of throat clearing, throat mucus, breathing difficulty, troublesome cough, and heartburn sensation, while all RFS subdomains except granuloma improved significantly. In subgroup analyses, no significant differences were found between subgroups based on age, OSA severity, or BMI. CONCLUSION: OSA surgery has the potential to alleviate both LPR symptoms and laryngoscopic. RESULTS: Additional research integrating more objective techniques and novel treatment strategies is required to better comprehend the clinical impact of OSA surgery on LPR.

11.
Anal Chem ; 83(5): 1603-8, 2011 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-21280615

RESUMO

In this paper, we propose a microfluidic device that is capable of generating a concentration gradient followed by parallel droplet formation within channels with a simple T-junction geometry. Linear concentration gradient profiles can be obtained based on fluid diffusion under laminar flow. Optimized conditions for generating a linear concentration gradient and parallel droplet formation were investigated using fluorescent dye. The concentration gradient profile under diffusive mixing was dominated by the flow rate at sample inlets, while parallel droplet formation was affected by the channel geometry at both the inlet and outlet. The microfluidic device was experimentally characterized using optimal layout and operating conditions selected through a design process. Furthermore, in situ enzyme kinetic measurements of the ß-galactosidase-catalyzed hydrolysis of resorufin-ß-d-galactopyranoside were performed to demonstrate the application potential of our simple, time-effective, and low sample volume microfluidic device. We expect that, in addition to enzyme kinetics, drug screening and clinical diagnostic tests can be rapidly and accurately performed using this droplet-based microfluidic system.


Assuntos
Enzimas/química , Microfluídica/métodos , Cinética
12.
Cell Tissue Res ; 345(3): 415-23, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21866312

RESUMO

Stem cell therapy requires large numbers of stem cells to replace damaged tissues, but only limited numbers of stem cells can be harvested from a single patient. To obtain large quantities of stem cells with differentiation potential, we explored a spinner culture system using human extracellular matrix (hECM) powders. The hECM was extracted from adipose tissue and fabricated into powders. Human adipose-derived stem cells (hASCs) were isolated, seeded on hECM powders, and cultivated in a spinner flask. The 3-D culture system, using hECM powders, was highly effective for promoting cell proliferation. The number of hASCs in the 3-D culture system significantly increased for 10 days, resulting in an approximately 10-fold expansion, whereas a traditional 2-D culture system showed just a 2.8-fold expansion. Surface markers, transcriptional factors, and differentiation potential of hASCs were assayed to identify the characteristics of proliferated cells in 3-D culture system. The hASCs expressed the pluripotency markers, Oct-4 and Sox-2 during 3-D culture and retained their capacity to differentiate into adipogenic, osteogenic, and chondrogenic lineages. These findings demonstrate that the 3-D culture systems using hECM powders provide an efficient in vitro environment for stem cell proliferation, and could act as stem cell delivery carriers for autologous tissue engineering and cell therapy.


Assuntos
Tecido Adiposo/citologia , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Matriz Extracelular/metabolismo , Células-Tronco/citologia , Adulto , Adesão Celular , Diferenciação Celular/genética , Linhagem da Célula/genética , Proliferação de Células , Matriz Extracelular/ultraestrutura , Citometria de Fluxo , Regulação da Expressão Gênica , Humanos , Imuno-Histoquímica , Células-Tronco Pluripotentes/citologia , Pós , Células-Tronco/ultraestrutura , Adulto Jovem
13.
Langmuir ; 27(17): 10993-9, 2011 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-21732692

RESUMO

Core-shell nanofibers are of great interest in the field of tissue engineering and cell biology. We fabricated porous core-shell fiber networks using an electrospinning system with a water-immersed collector. We hypothesized that the phase separation and solvent evaporation process would enable the control of the pore formation on the core-shell fiber networks. To synthesize porous core-shell fiber networks, we used polycaprolactone (PCL) and gelatin. Quantitative analysis showed that the sizes of gelatin-PCL core-shell nanofibers increased with PCL concentrations. We also observed that the shapes of the pores created on the PCL fiber networks were elongated, whereas the gelatin-PCL core-shell fiber networks had circular pores. The surface areas of porous nanofibers were larger than those of the nonporous nanofibers due to the highly volatile solvent and phase separation process. The porous core-shell fiber network was also used as a matrix to culture various cell types, such as embryonic stem cells, breast cancer cells, and fibroblast cells. Therefore, this porous core-shell polymeric fiber network could be a potentially powerful tool for tissue engineering and biological applications.


Assuntos
Nanofibras/química , Animais , Células Cultivadas , Eletroquímica , Gelatina/química , Humanos , Imuno-Histoquímica , Teste de Materiais , Camundongos , Tamanho da Partícula , Poliésteres/química , Porosidade , Propriedades de Superfície , Água/química
14.
Am J Chin Med ; 49(8): 1897-1912, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34961415

RESUMO

Ginsenosides of orally administered red ginseng (RG) extracts are metabolized and absorbed into blood. Here, we examined the pharmacokinetic profiles of ginsenosides Rd and Rg3 in mice orally gavaged with RG, then investigated the correlations between these and gut microbiota composition. RG water extract (RGw), RG ethanol extract (RGe), or fermented RGe (fRGe) was orally gavaged in mice. The plasma concentrations of the ginsenosides were determined, and the gut microbiota composition was analyzed. RGe and fRGe-treated mice showed higher plasma concentration levels of ginsenoside Rd compared with RGw-treated mice; particularly, ginsenoside Rd absorbed was substantially high in fRGe-treated mice. Oral administration of RG extracts modified the gut microbiota composition; the modified gut microbiota, such as Peptococcaceae, Rikenellaceae, and Hungateiclostridiaceae, were closely correlated with the absorption of ginsenosides, such as Rd and Rg3. These results suggest that oral administration of RG extracts can modify gut microbiome, which may consequently affect the bioavailability of RG ginsenosides.


Assuntos
Microbioma Gastrointestinal , Ginsenosídeos , Panax , Administração Oral , Animais , Camundongos
15.
Cancer Sci ; 101(6): 1521-8, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20331628

RESUMO

Hepatocellular carcinoma is one of the most lethal cancers worldwide. More accurate stratification of patients at risk is necessary to improve its clinical management. As epithelial-mesenchymal transition is critical for the invasiveness and metastasis of human cancers, we investigated expression profiles of 12 genes related to epithelial-mesenchymal transition through a real-time polymerase chain reaction. From a univariate Cox analysis for a training cohort of 128 hepatocellular carcinoma patients, four candidate genes (E-cadherin [CDH1], inhibitor of DNA binding 2 [ID2], matrix metalloproteinase 9 [MMP9], and transcription factor 3 [TCF3]) with significant prognostic values were selected to develop a risk score of patient survival. Patients with high risk scores calculated from the four-gene signature showed significantly shorter overall survival times. Moreover, the multivariate Cox analysis revealed that four-gene signature (P = 0.0026) and tumor stage (P = 0.0023) were independent prognostic factors for overall survival. Subsequently, the four-gene signature was validated in an independent cohort of 231 patients from three institutions, in which high risk score was significantly correlated with shorter overall survival (P = 0.00011) and disease-free survival (P = 0.00038). When the risk score was entered in a multivariate Cox analysis with tumor stage only, both the risk score (P = 0.0046) and tumor stage (P = 2.6 x 10(-9)) emerged as independent prognostic factors. In conclusion, we suggest that the proposed gene signature may improve the prediction accuracy for survival of hepatocellular carcinoma patients, and complement prognostic assessment based on important clinicopathologic parameters such as tumor stage.


Assuntos
Carcinoma Hepatocelular/patologia , Células Epiteliais/patologia , Perfilação da Expressão Gênica , Neoplasias Hepáticas/patologia , Mesoderma/patologia , Adulto , Idoso , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidade , Feminino , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Curva ROC , Risco
16.
Anal Chem ; 82(12): 5290-5, 2010 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-20503972

RESUMO

A surface-enhanced Raman scattering (SERS)-based gradient optofluidic sensor has been developed for a fast and sensitive immunoassay. In this work, a novel microfluidic sensor with functional internal structures has been designed and fabricated. This sensor is composed of three compartments consisting of the gradient channel that serially dilutes the target marker, the injection and mixing area of antibody-conjugated hollow gold nanospheres and magnetic beads, and the trapping area of sandwich immunocomplexes using multiple solenoids. Quantitative analysis of a specific target marker is performed by analyzing its characteristic SERS signals. This SERS-based gradient optofluidic sensor can replace the set of microwells or microtubes used in manual serial dilutions that have been traditionally used in enzyme-linked immunosorbent assay (ELISA)-type assays. The limit of detection for rabbit immunoglobin (IgG) is estimated to be 1-10 ng/mL. This novel SERS-based optofluidic immunoassay system is expected to be a powerful clinical tool for the fast and sensitive medical diagnosis of a disease.


Assuntos
Ouro/química , Imunoglobulina G/análise , Técnicas Analíticas Microfluídicas/instrumentação , Nanosferas/química , Análise Espectral Raman/instrumentação , Animais , Desenho de Equipamento , Imunoensaio/instrumentação , Imunoensaio/métodos , Limite de Detecção , Técnicas Analíticas Microfluídicas/métodos , Coelhos , Análise Espectral Raman/métodos
17.
J Nanosci Nanotechnol ; 20(11): 6665-6668, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32604493

RESUMO

This article describes the preparation of GeTe-based alloy films using a solution-based technique. The dissolution behavior of GeTe was initially examined by comparing the weight loss of GeTe powder in different solvents, and it was found that, unlike in the cases of n-butylamine and NH4OH, KOH fully dissolved GeTe to form an agglomerate-free solution. X-ray diffraction analysis revealed that the reaction between GeTe and KOH resulted in the formation of rhombohedral GeTe, cubic GeTe4, and hexagonal Te structures after drying. GeTe-based alloy films were then prepared by the spin coating of the GeTe-containing solutions on a silicon substrate. The surface morphology and reflectance properties of the prepared films were found to be highly dependent on the spin speed, with optimization of the spin coating parameter resulting in the deposition of a continuous and smooth film.

18.
Biomed Microdevices ; 11(3): 663-9, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19142733

RESUMO

Functional peptides from peptide libraries are frequently screened using an array format. We report here results of a feasibility study of fluorescence-based peptide screening using an array format on surface-modified glass. The surface of an amine-coated glass slide was modified to contain thiol groups by iminothiolane treatment. The epsilon-amine of the C-terminal lysine from a ligand peptide was iodinated and then spotted onto the thiolated glass surface to covalently conjugate the ligand peptide to the surface via a thioether bond. This covalent immobilization allowed the ligand peptides to withstand washing steps by tightly adhering to the glass surface and confining their subsequent binding reactions within a spotted area. Two representative peptides were used as the ligand peptides; a 'target' (positive) heptapeptide that could specifically bind to trypsin, and a 'control' (negative) hexapeptide that had no binding affinity with trypsin. When fluorescein isothiocyanate-labeled trypsin was reacted with the ligand peptides, the target peptide demonstrated distinctively higher (ca. 8.7-fold) fluorescence intensity that was easily differentiated from the control peptide by a fluorescence scanner. A separate experiment using a quartz crystal microbalance confirmed that the difference in binding mass (ca. 9.1-fold) was very close to that seen in fluorescence intensity. These results suggested a quantitative, 1:1 correlation between mass and fluorescence signals. Furthermore, a smaller spot volume and a higher ligand peptide concentration resulted in higher fluorescence signal intensity. This study provides information on the potential for using fluorescence-based screening of functional peptides on a glass array format.


Assuntos
Peptídeos/química , Peptídeos/metabolismo , Análise Serial de Proteínas/métodos , Compostos de Sulfidrila/metabolismo , Técnicas Biossensoriais , Estudos de Viabilidade , Fluoresceína-5-Isotiocianato/metabolismo , Corantes Fluorescentes/metabolismo , Vidro/química , Ouro/química , Halogenação , Ligantes , Modelos Químicos , Estrutura Molecular , Peso Molecular , Biblioteca de Peptídeos , Peptídeos/síntese química , Peptídeos/genética , Análise Serial de Proteínas/instrumentação , Ligação Proteica/genética , Estrutura Terciária de Proteína , Quartzo/química , Espectrometria de Fluorescência , Especificidade por Substrato , Tirosina/metabolismo
19.
J Biotechnol ; 133(1): 110-5, 2008 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-17961781

RESUMO

One of the major problems of wild-type lignin peroxidase (LiP) is its inactivity at the presence of excess H(2)O(2) and high concentration of aromatic compounds. Little is known about the substrate-binding site of LiP, and functionality improvement of LiP was not actively tried by genetic engineering and directed evolution. In order to improve LiPs functionality, we performed directed evolution with a colorimetric screening method. Finally, three types of LiP mutants were screened. The catalytic efficiency of the variants toward 2,4-dichlorophenol (DCP) degradation activity and the stability against H(2)O(2) was increased over the wild type. The K(m) value of the variants toward H(2)O(2) was increased, but K(m) value toward 2,4-DCP degradation was reduced. Overall, The K(cat)/K(m) values of the mutants toward 2,4-DCP was increased ca. 4-fold, and that toward H(2)O(2) was increased ca. 89-fold. Amino acid sequence analysis indicated that the most of the mutations were located on the enzyme surface. We expect that these results coupled with recombining mutation can be successfully applied to the molecular evolution cycles for screening of LiPs and other oxidative enzymes with improved functionality and stability.


Assuntos
Clorofenóis/química , Embaralhamento de DNA/métodos , Melhoramento Genético/métodos , Peróxido de Hidrogênio/química , Peroxidases/química , Saccharomyces cerevisiae/fisiologia , Biodegradação Ambiental , Ativação Enzimática , Estabilidade Enzimática , Peroxidases/genética
20.
J Chromatogr A ; 1161(1-2): 9-14, 2007 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-17543979

RESUMO

Recent technical advances in biorecognition engineering and microparticle fabrication enabled us to develop a single-step purification process using magnetic particles (MPs). The process is simple, efficacious, easy to automate, and economical. The method immobilizes the ligand molecule in a particular orientation on commercial MPs that have surface carboxyl groups. Mouse IgG and anti-mouse IgG antibody were the model capture and ligand molecules for this study. The immunobinding efficacy of anti-mouse IgG antibody using "oriented immobilization" was compared with the efficacy of a conventional amine-coupling system that results in random orientation and of another standard method, the biotin-streptavidin system. The oriented immobilization was accomplished by oxidizing the sugar moiety in the CH(2) domain of the antibody's Fc and covalently conjugating the moiety to the hydrazine-coated MP. The specific binding affinity of the oriented immobilization process was about 2.5 times that of the amine-coupling system, and selectivity from a binary mixture was about 2 times greater for the oriented immobilization method. Results were nearly identical for the biotin-streptavidin system and the oriented immobilization system, matching the calculated binding stoichiometry between mouse IgG and anti-mouse IgG antibody. The binding improvement over the amine-coupling system shown by assay was confirmed by a separate surface plasmon resonance experiment. In summary, the oriented immobilization method was as effective as the streptavidin-biotin system, yet simpler and cost-effective.


Assuntos
Anticorpos/imunologia , Animais , Anticorpos/química , Sítios de Ligação de Anticorpos , Magnetismo , Camundongos , Oxirredução , Ressonância de Plasmônio de Superfície
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