Browsing by Author "Shen, Mo-Yuan"

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Diversity of sugar acceptor of glycosyltransferase 1 from Bacillus cereus and its application for glucoside synthesis
(2016-05)
Chiu, Hsi-Ho
;
Shen, Mo-Yuan
;
Liu, Yuan-Ting
;
Fu, Yu-Lieh
;
Chiu, Yu-An
Glycosyltransferase 1 from Bacillus cereus (BcGT1) catalyzes the transfer of a glucosyl moiety from uridine diphosphate glucose (UDP-glucose) to various acceptors; it was expressed and characterized. The specificity of acceptors was found to be broad: more than 20 compounds classified into O-, S-, and N-linkage glucosides can be prepared with BcGT1 catalysis. Based on this work, we conclude that the corresponding acceptors of these compounds must possess the following features: (1) the acceptors must contain at least one aromatic or fused-aromatic or heteroaromatic ring; (2) the reactive hydroxyl or sulfhydryl or amino group can attach either on the aromatic ring or on its aliphatic side chain; and (3) the acceptors can be a primary, secondary, or even a tertiary amine. Four representative acceptors-fluorescein methyl ester, 17-beta-estradiol, 7-mercapto-4-methylcoumarin, and 6-benzylaminopurine-were chosen as a candidate acceptor for O-, S-, and N-glucosidation, respectively. These enzymatic products were purified and the structures were confirmed with mass and NMR spectra. As all isolated glucosides are beta-anomers, BcGT1 is confirmed to be an inverting enzyme. This study not only demonstrates the substrate promiscuity of BcGT1 but also showed the great application prospect of this enzyme in bioconversion of valuable bioactive molecules.
Facile Fabrication of a Sensor with a Bifunctional Interface for Logic Analysis of the New Delhi Metallo-beta-Lactamase (NDM)-Coding Gene
(2016-02)
Kuo, Tsui-Ming
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Shen, Mo-Yuan
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Huang, Shih-Ying
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Li, Yaw-Kuen
;
Chuang, Min-Chieh
Surface functionalization has attracted considerable interest from researchers because of its capability for facilitating the interface communication between an energy transducer and a biological system. We report newly synthesized N-(4-aminobenzoyl)-N\'-(4-maleimidobenzoyl)1,2-ethylenediamine (AME) to promote the modification of the surface with thiolated DNA and 3-((4-aminophenyl)dimethylammonio)propane-1-sulfonate (APSB) for the facile formation of a bifunctional interface forming an antifouling surface. Through the formation of diazonium ion, electrochemically reductive deposition of the two arylamines can fabricate simultaneously and effectively a bifunctional surface on a gold electrode and install a DNA probe to form a sensor; the sensor was applied to detect three genetic fragments of the New Delhi Metallo-beta-Lactamase (NDM)-coding gene. Effects of the diazotization and the conditions of electrochemical deposition upon the sensing signals were investigated in connection with enumerating the accessible maleimide groups and assessing the diffusion resistance of the electroactive indicator. The detection limit given by the diazonium-constructed system was improved to attain the level of 54 pM, an advance over a conventional self assembled monolayer.
Preparation of High-Performance Water-Soluble Quantum Dots for Biorecognition through Fluorescence Resonance Energy Transfer
(2012-12-01)
Huang, Chin-Ping
;
Chao, Cheng-Fu
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Shen, Mo-Yuan
;
Chen, Teng-Ming
;
Li, Yaw-Kuen
An improved method for the synthesis of high-performance and water-soluble quantum dots (QDs) involving the encapsulation of mercaptosuccinic acid coated QDs (MSA-QDs) with poly(diallyldimethylammonium chloride) (PDDA) followed by their direct photoactivation with fluorescent radiation near 295 K to yield PDDA-coated QDs (PDDA-QDs) has been demonstrated. The quantum yield (QY) of the PDDA-QDs was significantly improved from 0.6 (QY of MSA-QDs) to 48?%. By using this synthetic strategy, highly photoluminescent PDDA-QDs of varied size were readily prepared. The surface properties of PDDA-QDs and MSA-QDs were extensively characterized. The highly luminescent and positively charged PDDA-QDs serve as a useful and convenient tool for protein adsorption. With a ?5-3-ketosteroid isomerase adsorbed PDDA-QD complex, the biorecognition of steroids was demonstrated through the application of fluorescent resonance energy transfer.
Rapid construction of an effective antifouling layer on a Au surface via electrodeposition
(2014)
Li, Bor-Ran
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Shen, Mo-Yuan
;
Yu, Hsiao-Hua
;
Li, Yaw-Kuen
;
應用化學系
A new approach to immobilize zwitterionic molecules rapidly and highly efficiently on a gold surface applies aniline-based electro-deposition. The zwitterion-functionalized antifouling surface enables a decrease of the adsorption of non-specific proteins by 95% from fetal bovine serum (FBS, 10%).
Silicon nanowire field-effect-transistor based biosensors: From sensitive to ultra-sensitive
(2014-10-15)
Shen, Mo-Yuan
;
Li, Bor-Ran
;
Li, Yaw-Kuen
;
應用化學系
;
Department of Applied Chemistry
Silicon nanowire field effect transistors (SiNW-FETs) have shown great promise as biosensors in highly sensitive, selective, real-time and label-free measurements. While applications of SiNW-FETs for detection of biological species have been described in several publications, less attention has been devoted to summarize the conjugating methods involved in linking organic bio-receptors with the inorganic transducer and the strategies of improving the sensitivity of devices. This article attempts to focus on summarizing the various organic immobilization approaches and discussing various sensitivity improving strategies, that include (I) reducing non-specific binding, (II) alignment of the probes, (III) enhancing signals by charge reporter, (IV) novel architecture structures, and (V) sensing in the subthreshold regime. (C) 2014 Elsevier B.V. All rights reserved.
Water-soluble germanium nanoparticles cause necrotic cell death and the damage can be attenuated by blocking the transduction of necrotic signaling pathway
(2011-12-15)
Ma, Yu-Hsin
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Huang, Chin-Ping
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Tsai, Jia-Shiuan
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Shen, Mo-Yuan
;
Li, Yaw-Kuen
Water-soluble germanium nanoparticles (wsGeNPs) with allyamine-conjugated surfaces were fabricated and emit blue fluorescence under ultraviolet light. The wsGeNP was physically and chemically stable at various experimental conditions. Cytotoxicity of the fabricated wsGeNP was examined. KIT assay demonstrated that wsGeNP possessed high toxicity to cells and clonogenic survival assay further indicated that this effect was not resulted from retarding cell growth. Flow cytometric analysis indicated that wsGeNP did not alter the cell cycle profile but the sub-G1 fraction was absent from treated cells. Results from DNA fragmentation and propidium iodide exclusion assays also suggested that apoptotic cell death did not occur in cells treated with wsGeNP. Addition of a necrosis inhibitor, necrostatin-1, attenuated cell damage and indicated that wsGeNP caused necrotic cell death. Cell signaling leads to necrotic death was investigated. Intracellular calcium and reactive oxygen species (ROS) levels were increased upon wsGeNP treatment. These effects can be abrogated by BAPTA-AM and N-acetyl cysteine respectively, resulting in a reduction in cell damage. In addition, wsGeNP caused a decrease in mitochondrial membrane potential (MMP) which could be recovered by cyclosporine A The cellular signaling events revealed that wsGeNP increase the cellular calcium level which enhances the production of ROS and leads to a reduction of MMP, consequentially results in necrotic cell death. (C) 2011 Elsevier Ireland Ltd. All rights reserved.