Publications by authors named "David Shiuan"

Alzheimer's disease (AD) is a global health issue affecting millions of elderly people worldwide. The aim of the present study was to identify novel anti-AD peptides isolated from albumin. Anti-AD activities of the peptides were evaluated via inhibitory activities on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE).

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The objective of this work was to identify a novel ACE inhibitory peptide from myosin using a number of in silico methods. Myosin was evaluated as a substrate for use in the generation of ACE inhibitory peptides using BIOPEP and ExPASy PeptideCutter. Then the ACE inhibitory activity prediction of peptides in silico was evaluated using the program peptide ranker, following the database search of known and unknown peptides using the program BIOPEP.

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Many drugs for the treatment of hypercholesterolemia are targeting the enzymes involved in human cholesterol biosynthesis pathway. Squalene synthase, the rate-limiting enzyme located at the downstream of cholesterol synthesis pathway, has become a better candidate to develop next-generation hypocholesterolemia drugs. In the present study, we cloned and expressed the recombinant human squalene synthase (hSQS) as the lure to isolate potential peptide inhibitors from screening the conformation-constrained phage-displayed cyclic peptide c7c library.

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Many studies have demonstrated the role of elevated levels of serum cholesterol in the pathogenesis of atherosclerosis and coronary heart disease. Various drugs targeting the key enzymes involved in the cholesterol biosynthesis pathway have been investigated for the treatment of hypercholesterolemia. Human squalene synthase has been one of the most important targets for therapeutic intervention.

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Dengue is the most widespread arbovirus infection and poses a serious health and economic issue in tropical and subtropical countries. Currently no licensed vaccine or compounds can be used to prevent or manage the severity of dengue virus (DENV) infection. Honokiol, a lignan biphenol derived from the Magnolia tree, is commonly used in Eastern medicine.

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Cholesterol plays an important role in living cells. However, a very high level of cholesterol may lead to atherosclerosis. HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase is the key enzyme in the cholesterol biosynthesis pathway, and the statin-like drugs are inhibitors of human HMG-CoA reductase (hHMGR).

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α-Cyclic tripeptides (CtPs) are the most rigid members of the cyclic peptide family. However, due to their synthetic difficulty, biological activity has remained undisclosed. The incorporation of side-chain-protected natural amino acids into functional CtPs was performed to explore the potential biological functions.

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Hypercholesterolemia may lead to obesity and cardiovascular diseases. To prevent hypercholesterolemia, many drugs have been developed while searching for better drugs to treat hypercholesterolemia has never been ended. Other than small molecule drugs, peptide drugs are gaining more visibilities in many therapeutic areas.

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Enterovirus 71 (EV71), one of the major causative agents of hand, foot, and mouth disease (HFMD), is now recognized as an emerging neurotropic virus in Asia and may cause severe neurologic complications and mortalities. Laboratory diagnosis of EV71 infection must be efficient and accurate, which could be accomplished by various immunoassays. In this study we use a live EV71 isolate, Tainan/4643/98, with genotype C2 as an immunogen to sensitize BALB/c (H-2(d)) mice and then generate the EV71-specific murine monoclonal antibodies.

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The phosphoenolpyruvate phosphotransferase system (PTS) is ubiquitous in eubacteria and absent from eukaryotes. The system consists of two phosphoryl carriers, enzyme I (EI) and the histidine-containing phosphoryl carrier protein (HPr), and several PTS transporters, catalyzing the concomitant uptake and phosphorylation of several carbohydrates. Since a deficiency of EI in bacterial mutants lead to severe growth defects, EI could be a drug target to develop antimicrobial agents.

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Dendritic cells (DCs) are antigen presenting cells, which can present antigens to T-cells and play an important role in linking innate and adaptive immunity. DC maturation can be induced by many stimuli, including pro-inflammatory cytokines and bacterial products, such as lipopolysaccharides (LPS). Here, we examined the immunomodulatory effects of marine cembrane compounds, (9E,13E)-5-acetoxy-6-hydroxy-9,13-dimethyl-3- methylene-3,3a,4,5,6,7,8,11,12,14a-decahydro-2H-cyclotrideca[b]furan-2-one (1), (9E,13E)- 5-acetoxy-6-acetyl-9,13-dimethyl-3-methylene-3,3a,4,5,6,7,8,11,12,14a-decahydro-2H-cyclotrideca[b]furan-2-one (2), lobocrassin B (3), (-)14-deoxycrassin (4), cembranolide B (5) and 13-acetoxysarcocrassolide (6) isolated from a soft coral, Lobophytum crassum, on mouse bone marrow-derived dendritic cells (BMDCs).

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Antimicrobial peptides play an important role in the innate immune response and host defense mechanism. In the present study, we employed phage display technique to screen for inhibitors which may block the phosphoenolpyruvatedependent phosphotransferase system (PTS) pathway and hence retard cell growth. The recombinant histidine-containing phosphocarrier HPr protein was prepared as the target to screen for the tight binders from the phage-displayed random peptide library Ph.

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This investigation was designed to determine the inhibitory effects and mechanisms of n-butylidenephthalide (BP) from Angelica sinensis on smooth muscle cell (SMC) proliferation in vitro and in balloon injured rat carotid artery. Treatment of cultured rat aorta SMC-derived A7r5 cells with 25-100 μg/mL BP significantly inhibited the proliferation and arrested the cell cycle in G(0)/G(1) phase. BP induced the expression and migration of Nur77 from the nucleus to the cytoplasm.

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Mycoplasma hyopneumoniae colonizes at the porcine respiratory-ciliated epithelial cells and causes the enzootic pneumonia of swine. The adhesion step is crucial in the colonization process. A few adhesion molecules have been characterized, and the concurrent receptors from the porcine ciliated cells have also been suggested to recognize the adhesion molecules.

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Mycoplasma hyopneumoniae is an important pathogen of pigs causing enzootic pneumonia of swine. The pathogen remains largely enigmatic as far as the host-pathogen interactions are concerned. In the present study, the protein profiles of two strains of M.

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Association with nucleic acid has been recognized as a unique role of lysozyme and may explain why lysozyme was called a killer protein against HIV infection. In the present study, we characterized the interactions of lysozyme and its derived peptides with a biotin-labeled pUC19 plasmid DNA. Real-time detection of the macromolecular interaction was performed using the SPR (surface plasmon resonance) spectroscopy.

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Mycoplasmas in general are rarely exposed to severe environmental changes except during its colonization and infection processes. Genomic analysis indicates that Mycoplasma hyopneumoniae possesses the genes of a single sigma factor and the HrcA repressor of negative regulation of the heat-shock response. A perfect inverted repeat sequence (5'-CTGGCACTT-N(9)-AAGTGCCAA-3') upstream of the DnaK gene has also been identified.

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The protective effects of a freeze-dried extracts of vegetables and fruits (BauYuan; BY) on the hydroxyl radical-mediated DNA strand breakages and the structural integrity of human red blood cells (RBCs) were investigated. First, the supercoiled plasmid (pEGFP-C1) DNA was subjected to oxidation damage by an ascorbate-fortified Fenton reaction and the protective effects were analyzed by agarose gel electrophoresis. In the absence of BY extracts, exposure of the high-throughput .

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Antibodies with enzymatic activity were named abzymes or catalytic antibodies. In the present study, the lipolytic abzymes were selected from the phage displayed antibody libraries against a transition state analog (TSA) of lipases/esterases. After three rounds of selection, four monoclonal phage particles capable of binding significantly with the TSA were obtained.

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Biotin is an important nutritional supplement but is difficult to manufacture effectively. Here we present a trial of biotin production using the food yeast Candida utilis. In this system, we cloned the C.

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Phage display techniques have been widely employed to map the epitope structures which served as the basis for developing molecular vaccines. In the present study, we applied this technique to map the epitopes of Mycoplasma hyopneumoniae, the etiologic agent causing swine enzootic pneumonia, and evaluated directly the immune responses in mice of the selected phage-displayed epitopes (phagotopes). Two phage-displayed random peptide libraries were biopanned with the protein A-purified IgG of the rabbit anti-M.

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Current serological tests for melioidosis, using impure or uncharacterized cell antigens from Burkholderia pseudomallei, have problems in detection sensitivity and specificity. Therefore, we designed and expressed the recombinant flagellin (truncated at both the N- and C-terminal ends), and used the antigen to develop an indirect enzyme-linked immunosorbent assay (ELISA) to diagnose melioidosis. Comparison of the immunoreactivities of the full-length and truncated flagellins reveals that the truncated flagellin performed much better in detection specificity and sensitivity.

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Phage-displayed peptide systems have been used to identify the immunogenic epitopes and to develop the design of peptide-based or peptide-displaying phages themselves as vaccine candidates. To estimate the humoral immunity of phage-based vaccine, it is necessary to evaluate the antibody response specifically directed at the displayed peptide. Enzyme-linked immunosorbent assays (ELISAs) and Western blot analysis are commonly used for this purpose.

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Mycoplasma hyopneumoniae is the etiological agent of swine enzootic pneumonia, a chronic nonfatal disease affecting pigs of all ages. The goal of this study was to design DNA vaccines by constructing plasmid pcDNA3/P42, carrying the heat shock protein gene P42 of M. hyopneumoniae, and to evaluate the immune responses elicited in BALB/c mice.

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