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Find video protocols related to scientific articles indexed in Pubmed.
Genomic and transcriptomic analyses of the medicinal fungus Antrodia cinnamomea for its metabolite biosynthesis and sexual development.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-21-2014
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Antrodia cinnamomea, a polyporus mushroom of Taiwan, has long been used as a remedy for cancer, hypertension, and hangover, with an annual market of over $100 million (US) in Taiwan. We obtained a 32.15-Mb genome draft containing 9,254 genes. Genome ontology enrichment and pathway analyses shed light on sexual development and the biosynthesis of sesquiterpenoids, triterpenoids, ergostanes, antroquinonol, and antrocamphin. We identified genes differentially expressed between mycelium and fruiting body and 242 proteins in the mevalonate pathway, terpenoid pathways, cytochrome P450s, and polyketide synthases, which may contribute to the production of medicinal secondary metabolites. Genes of secondary metabolite biosynthetic pathways showed expression enrichment for tissue-specific compounds, including 14-?-demethylase (CYP51F1) in fruiting body for converting lanostane to ergostane triterpenoids, coenzymes Q (COQ) for antroquinonol biosynthesis in mycelium, and polyketide synthase for antrocamphin biosynthesis in fruiting body. Our data will be useful for developing a strategy to increase the production of useful metabolites.
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Structural insights of the ssDNA binding site in the multifunctional endonuclease AtBFN2 from Arabidopsis thaliana.
PLoS ONE
PUBLISHED: 08-26-2014
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The multi S1/P1 nuclease AtBFN2 (EC 3.1.30.1) encoded by the Arabidopsis thaliana At1g68290 gene is a glycoprotein that digests RNA, ssDNA, and dsDNA. AtBFN2 depends on three zinc ions for cleaving DNA and RNA at 3'-OH to yield 5'-nucleotides. In addition, AtBFN2's enzymatic activity is strongly glycan dependent. Plant Zn(2+)-dependent endonucleases present a unique fold, and belong to the Phospholipase C (PLC)/P1 nuclease superfamily. In this work, we present the first complete, ligand-free, AtBFN2 crystal structure, along with sulfate, phosphate and ssDNA co-crystal structures. With these, we were able to provide better insight into the glycan structure and possible enzymatic mechanism. In comparison with other nucleases, the AtBFN2/ligand-free and AtBFN2/PO4 models suggest a similar, previously proposed, catalytic mechanism. Our data also confirm that the phosphate and vanadate can inhibit the enzyme activity by occupying the active site. More importantly, the AtBFN2/A5T structure reveals a novel and conserved secondary binding site, which seems to be important for plant Zn(2+)-dependent endonucleases. Based on these findings, we propose a rational ssDNA binding model, in which the ssDNA wraps itself around the protein and the attached surface glycan, in turn, reinforces the binding complex.
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Immobilization of Brassica oleracea chlorophyllase 1 (BoCLH1) and Candida rugosa lipase (CRL) in magnetic alginate beads: an enzymatic evaluation in the corresponding proteins.
Molecules
PUBLISHED: 08-07-2014
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Enzymes have a wide variety of applications in diverse biotechnological fields, and the immobilization of enzymes plays a key role in academic research or industrialization due to the stabilization and recyclability it confers. In this study, we immobilized the Brassica oleracea chlorophyllase 1 (BoCLH1) or Candida rugosa lipase (CRL) in magnetic iron oxide nanoparticles-loaded alginate composite beads. The catalytic activity and specific activity of the BoCLH1 and CRL entrapped in magnetic alginate composite beads were evaluated. Results show that the activity of immobilized BoCLH1 in magnetic alginate composite beads (3.36±0.469 U/g gel) was higher than that of immobilized BoCLH1 in alginate beads (2.96±0.264 U/g gel). In addition, the specific activity of BoCLH1 beads (10.90±1.521 U/mg protein) was higher than that immobilized BoCLH1 in alginate beads (8.52±0.758 U/mg protein). In contrast, the immobilized CRL in magnetic alginate composite beads exhibited a lower enzyme activity (11.81±0.618) than CRL immobilized in alginate beads (94.83±7.929), and the specific activity of immobilized CRL entrapped in magnetic alginate composite beads (1.99±0.104) was lower than immobilized lipase in alginate beads (15.01±1.255). A study of the degradation of magnetic alginate composite beads immersed in acidic solution (pH 3) shows that the magnetic alginate composite beads remain intact in acidic solution for at least 6 h, indicating the maintenance of the enzyme catalytic effect in low-pH environment. Finally, the enzyme immobilized magnetic alginate composite beads could be collected by an external magnet and reused for at least six cycles.
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Incidence and predicted risk factors of pressure ulcers in surgical patients: experience at a medical center in Taipei, Taiwan.
Biomed Res Int
PUBLISHED: 03-19-2014
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To explore the context of incidence of and associated risk factors for pressure ulcers amongst the population of surgical patients.
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Acid-induced hyperalgesia and anxio-depressive comorbidity in rats.
Physiol. Behav.
PUBLISHED: 01-23-2014
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Fibromyalgia is a prevalent disorder characterized by chronic widespread pain (CWP) and complex comorbid symptoms. A CWP model is developed through repeated unilateral intramuscular injections of acid saline resulting in bilateral mechanical hyperalgesia in rats. The present study aims to evaluate whether both anxious and depressive comorbidities exist in this acid-induced pain model, similarly to patients with CWP syndromes. The anxiety-like behaviors were evaluated using the open field and elevated plus maze tests, and depression-like behaviors were measured by the forced swimming, sucrose consumption, and sucrose preference tests. The pain group receiving acidic saline displayed significantly lower paw withdrawal thresholds for 4weeks than animals in the vehicle group after repetitive intramuscular injections. The pain group showed a significantly shorter duration of exploring the central zone of the open field and the open arms of the elevated plus maze compared to the vehicle group. The pain group had a significantly lower preference for and consumption of the hedonic sucrose. Moreover, rats with chronic pain showed significantly longer immobility than the vehicle group in the forced swimming test. The results indicate that psychiatric behaviors are exacerbated in the CWP model. This study provides evidence for the validity of the acid-induced pain model analogous to patients with CWP syndromes.
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Simultaneous production of fatty acid methyl esters and diglycerides by four recombinant Candida rugosa lipase's isozymes.
Food Chem
PUBLISHED: 01-14-2014
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In this study, the catalytic efficiency of four recombinant CRL (Candida rugosa lipase) isozymes (LIP1-LIP4) towards the production of fatty acid methyl ester (FAME) was compared and evaluated as an alternative green method for industrial applications. The results indicated that the recombinant C. rugosa LIP1 enzyme exhibited the highest catalytic efficiency for FAME production compared to the recombinant C. rugosa LIP2-LIP4 enzymes. The optimal conditions were as follows: pH 7.0, methanol/soybean oil molar ratio: 3/1, enzyme amount: 2U (1.6 ?L), reaction temperature: 20°C, 22 h of reaction time, and 3 times of methanol addition (1 mol/6h), and resulted in 61.5 ± 1.5 wt.% of FAME conversion. The reaction product contained also 10 wt.% of DAG with a ratio of 1,3-DAG to 1,2-DAG of approximately 4:6, and can be potentially used in industrial applications as a food emulsifier.
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Progress in sensorimotor rehabilitative physical therapy programs for stroke patients.
World J Clin Cases
PUBLISHED: 01-02-2014
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Impaired motor and functional activity following stroke often has negative impacts on the patient, the family and society. The available rehabilitation programs for stroke patients are reviewed. Conventional rehabilitation strategies (Bobath, Brunnstrom, proprioception neuromuscular facilitation, motor relearning and function-based principles) are the mainstream tactics in clinical practices. Numerous advanced strategies for sensory-motor functional enhancement, including electrical stimulation, electromyographic biofeedback, constraint-induced movement therapy, robotics-aided systems, virtual reality, intermittent compression, partial body weight supported treadmill training and thermal stimulation, are being developed and incorporated into conventional rehabilitation programs. The concept of combining valuable rehabilitative procedures into "a training package", based on the patient's functional status during different recovery phases after stroke is proposed. Integrated sensorimotor rehabilitation programs with appropriate temporal arrangements might provide great functional benefits for stroke patients.
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Establishment of the Metabolite Profile for an Antrodia cinnamomea Health Food Product and Investigation of Its Chemoprevention Activity.
J. Agric. Food Chem.
PUBLISHED: 08-30-2013
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Antrodia cinnamomea is an edible fungus endemic to Taiwan that has been attributed with health promotion benefits. An A. cinnamomea mycelium health food product, which was produced by solid-state culture, was selected as the target for investigation in this study. Fourteen representative metabolites of A. cinnamomea mycelium (EMAC) were selected as index compounds to establish the metabolite profile for evaluation of EMAC product quality. It was also demonstrated that EMAC administration significantly reduced liver inflammation and serum oxidative stress in vivo. 4-Acetylantroquinonol B obtained by a bioactivity-guided fractionation from EMAC was able to not only inhibit LPS-induced nitric oxide formation in macrophages but also protect against ethanol-induced oxidative stress in liver cells. The results suggest this A. cinnamomea product might be a potent antioxidative and anti-inflammatory supplement for chemoprevention.
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Microfluidic one-step synthesis of Fe3O4-chitosan composite particles and their applications.
Int J Pharm
PUBLISHED: 06-20-2013
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This paper demonstrates a simple and easy approach for the one-step synthesis of Fe3O4-chitosan composite particles with tadpole-like shape. The length and diameter of the particles were adjustable from 638.3?m to ca. 798?m (length), and from 290?m to 412?m (diameter) by varying the flow rate of the dispersed phase. Mitoxantrone was used as the model drug in the drug release study. The encapsulation rate of the drug was 71% for chitosan particles, and 69% for magnetic iron oxide-chitosan particles, respectively. The iron oxide-chitosan composite particles had a faster release rate (up to 41.6% at the third hour) than the chitosan particles (about 24.6%). These iron oxide-chitosan composite particles are potentially useful for biomedical applications, such as magnetic responsive drug carriers, magnetic resonance imaging (MRI) enhancers, in the future.
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Musicians and non-musicians different reliance of features in consonance perception: A behavioral and ERP study.
Clin Neurophysiol
PUBLISHED: 02-27-2013
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The aim of this study was to compare the different features that musicians and non-musicians rely upon when they discern consonant and dissonant intervals. Previous studies have addressed this issue from the perspective of either the frequency ratio (Western music theory) or the frequency difference (psychoacoustics), but have not considered both features in a single and balanced study.
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The zona incerta modulates spontaneous spike-wave discharges in the rat.
J. Neurophysiol.
PUBLISHED: 02-27-2013
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The contribution of the zona incerta (ZI) of the thalamus on spike-wave discharges (SWDs) was investigated. Chronic recordings of bilateral cortices, bilateral vibrissa muscle, and unilateral ZI were performed in Long-Evans rats to examine the functional role of SWDs. Rhythmic ZI activity appeared at the beginning of SWD and was accompanied by higher-oscillation frequencies and larger spike magnitudes. Bilateral lidocaine injections into the mystacial pads led to a decreased oscillation frequency of SWDs, but the phenomenon of ZI-related spike magnitude enhancement was preserved. Moreover, 800-Hz ZI microstimulation terminates most of the SWDs and whisker twitching (WT; >80%). In contrast, 200-Hz ZI microstimulation selectively stops WTs but not SWDs. Stimulation of the thalamic ventroposteriomedial nucleus showed no obvious effect on terminating SWDs. A unilateral ZI lesion resulted in a significant reduction of 7- to 12-Hz power of both the ipsilateral cortical and contralateral vibrissae muscle activities during SWDs. Intraincertal microinfusion of muscimol showed a significant inhibition on SWDs. Our present data suggest that the ZI actively modulates the SWD magnitude and WT behavior.
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Paroxetine-induced Ca2+ movement and death in OC2 human oral cancer cells.
Chin J Physiol
PUBLISHED: 12-06-2011
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The effect of the antidepressant paroxetine on cytosolic free Ca2+ concentrations ([Ca2+]i) in OC2 human oral cancer cells is unclear. This study explored whether paroxetine changed basal [Ca2+]i levels in suspended OC2 cells by using fura-2 as a Ca2+-sensitive fluorescent dye. Paroxetine at concentrations between 100-1,000 microM increased [Ca2+]i in a concentration-dependent manner. The Ca2+ signal was reduced by 50% by removing extracellular Ca2+. Paroxetine-induced Ca2+ influx was inhibited by the store-operated Ca2+ channel blockers nifedipine, econazole and SK&F96365, and protein kinase C modulators. In Ca2+-free medium, pretreatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin abolished paroxetine-induced [Ca2+]i rise. Inhibition of phospholipase C with U73122 did not alter paroxetine-induced [Ca2+]i rise. Paroxetine at 10-50 microM induced cell death in a concentration-dependent manner. The death was not reversed when cytosolic Ca2+ was chelated with 1,2-bis(2-aminophenoxy)ethane-N,N,N,N-tetraacetic acid. Propidium iodide staining suggests that apoptosis plays a role in the death. Collectively, in OC2 cells, paroxetine induced [Ca2+]i rise by causing phospholipase C-independent Ca2+ release from the endoplasmic reticulum and Ca2+ influx via store-operated Ca2+ channels in a manner regulated by protein kinase C and phospholipase A2. Paroxetine (up to 50 microM) induced cell death in a Ca2+-independent manner.
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Characterization of codon-optimized recombinant candida rugosa lipase 5 (LIP5).
J. Agric. Food Chem.
PUBLISHED: 09-14-2011
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Recombinant Candida rugosa lipase 5 (LIP5) has been functionally expressed along with other isoforms in our laboratory. However, the characterization and codon optimization of LIP5 have not been done. In this work, we characterized, codon-optimized and compared LIP5 with commercial lipase. LIP5 activity on hydrolysis of p-nitrophenyl (p-NP) butyrate was optimal at 55 °C as compared with 37 °C of the commercial lipase. Several assays were also performed to determine the substrate specificity of LIP5. p-NP butyrate (C(4)), butyryl-CoA (C(4)), cholesteryl laurate (C(12)), and N-carbobenzoxy-l-tyrosine-p-nitrophenyl ester (l-NBTNPE) were found as preferred substrates of LIP5. Interestingly, LIP5 specificity on hydrolysis of amino acid-derivative substrates was shown to be the highest among any lipase isoforms, but it had very weak preference on hydrolyzing triacylglycerol substrates. LIP5 also displays a pH-dependent maximum activity of a lipase but an esterase substrate preference in general. The characterization of LIP5 along with that of LIP1-LIP4 previously identified shows that each lipase isoform has a distinct substrate preference and catalytic activity.
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Roles of Oxidative Stress, Apoptosis, PGC-1? and Mitochondrial Biogenesis in Cerebral Ischemia.
Int J Mol Sci
PUBLISHED: 08-01-2011
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The primary physiological function of mitochondria is to generate adenosine triphosphate through oxidative phosphorylation via the electron transport chain. Overproduction of reactive oxygen species (ROS) as byproducts generated from mitochondria have been implicated in acute brain injuries such as stroke from cerebral ischemia. It was well-documented that mitochondria-dependent apoptotic pathway involves pro- and anti-apoptotic protein binding, release of cytochrome c, leading ultimately to neuronal death. On the other hand, mitochondria also play a role to counteract the detrimental effects elicited by excessive oxidative stress. Recent studies have revealed that oxidative stress and the redox state of ischemic neurons are also implicated in the signaling pathway that involves peroxisome proliferative activated receptor-? (PPAR?) co-activator 1? (PGC1-?). PGC1-? is a master regulator of ROS scavenging enzymes including manganese superoxide dismutase 2 and the uncoupling protein 2, both are mitochondrial proteins, and may contribute to neuronal survival. PGC1-? is also involved in mitochondrial biogenesis that is vital for cell survival. Experimental evidence supports the roles of mitochondrial dysfunction and oxidative stress as determinants of neuronal death as well as endogenous protective mechanisms after stroke. This review aims to summarize the current knowledge focusing on the molecular mechanisms underlying cerebral ischemia involving ROS, mitochondrial dysfunction, apoptosis, mitochondrial proteins capable of ROS scavenging, and mitochondrial biogenesis.
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Closed-loop seizure control on epileptic rat models.
J Neural Eng
PUBLISHED: 07-20-2011
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In this paper numerous alternative treatments in addition to pharmacological therapy are proposed for their use in epileptic patients. Epileptic animal models can play a crucial role in the performance evaluation of new therapeutic techniques. The objective of this research is to first develop various epileptic rat models; second, develop a portable wireless closed-loop seizure controller including on-line seizure detection and real-time electrical stimulation for seizure elimination; and third, apply the developed seizure controller to the animal models to perform on-line seizure elimination. The closed-loop seizure controller was applied to three Long-Evans rats with spontaneous spike-wave discharges (non-convulsive) and three Long-Evans rats with epileptiform activities induced by pentylenetetrazol (PTZ) injection (convulsive) for evaluation. The seizure detection accuracy is greater than 92% (up to 99%), and averaged seizure detection latency is less than 0.6 s for both spontaneous non-convulsive and PTZ-induced convulsive seizures. The average false stimulation rate is 3.1%. Near 30% of PTZ-induced convulsive seizures need more than two times of 0.5 s electrical stimulation for suppression and 90% of the non-convulsive seizures can be suppressed by only one 0.5 s electrical stimulation.
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Metabolite profiles for Antrodia cinnamomea fruiting bodies harvested at different culture ages and from different wood substrates.
J. Agric. Food Chem.
PUBLISHED: 06-21-2011
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Antrodia cinnamomea is a precious edible fungus endemic to Taiwan that has long been used as a folk remedy for health promotion and for treating various diseases. In this study, an index of 13 representative metabolites from the ethanol extract of A. cinnamomea fruiting body was established for use in quality evaluation. Most of the index compounds selected, particularly the ergostane-type triterpenoids and polyacetylenes, possess good anti-inflammation activity. A comparison of the metabolite profiles of different ethanol extracts from A. cinnamomea strains showed silmilar metabolites when the strains were grown on the original host wood (Cinnamomum kanehirai) and harvested after the same culture time period (9 months). Furthermore, the amounts of typical ergostane-type triterpenoids in A. cinnamomea increased with culture age. Culture substrates also influenced metabolite synthesis; with the same culture age, A. cinnamomea grown on the original host wood produced a richer array of metabolites than A. cinnamomea cultured on other wood species. We conclude that analysis of a fixed group of compounds including triterpenoids, benzolics, and polyacetylenes constitutes a suitable, reliable system to evaluate the quality of ethanol extract from A. cinnamomea fruiting bodies. The evaluation system established in this study may provide a platform for analysis of the products of A. cinnamomea.
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Engineering the expression and biochemical characteristics of recombinant Candida rugosa LIP2 lipase by removing the additional N-terminal peptide and regional codon optimization.
J. Agric. Food Chem.
PUBLISHED: 05-31-2011
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Candida rugosa lipase (CRL), an important industrial enzyme, has been established, containing several different isoforms which were encoded by the high-identity lip gene family (lip1 to lip7). In this study, we compared the expression and biochemical characterization with three different engineered lip2 constructions in the yeast Pichia pastoris. Our results showed that lip2 (lip2) has an overall improvement of 50% higher production yield (1.446 U/mL) relative to that of nflip2 (0.964 U/mL) at 7 days of cultivation time. Codon-optimized lip2 (colip2) has a 2.3-fold higher production yield (2.182 U/mL) compared to that of lip2 (noncodon-optimized; 1.446 U/mL) and nflip2 (0.964 U/mL), with a cultivation time of 5 days. This finding demonstrated that the removal of the N-terminus and the regional codon optimization of the lip2 gene fragment at the 5 end can greatly increase the expression level of recombinant LIP2 in the P. pastoris system. The distinct biochemical properties of our purified recombinant nfLIP2 and LIP2 suggested that they are potentially useful for various industrial applications.
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Effect of intracranial administration of ethosuximide in rats with spontaneous or pentylenetetrazol-induced spike-wave discharges.
Epilepsia
PUBLISHED: 04-19-2011
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Generalized absence seizures are characterized by bilateral spike-wave discharges (SWDs), particularly in the frontoparietal cortical region. In WAG/Rij and GAERS rats with absence epilepsy, recent evidence indicates that SWDs arise first from the lateral somatosensory cortex (LSC), that is, the cortical focus theory. To further understand the cortical role in SWD generation, two epileptic rat models were assessed.
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Antroquinonol from ethanolic extract of mycelium of Antrodia cinnamomea protects hepatic cells from ethanol-induced oxidative stress through Nrf-2 activation.
J Ethnopharmacol
PUBLISHED: 04-13-2011
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In recent years, the medicinal mushroom Antrodia cinnamomea, known as "niu-chang chih" has received much attention with regard to its possible health benefits; especially its hepatoprotective effects against various drugs, toxins, and alcohol induced liver diseases. However, the molecular mechanism underlying this protective effect of Antrodia cinnamomea and its active compound antroquinonol was poorly understood. In the present study we evaluated to understand the hepatoprotective efficacy of antroquinonol and ethanolic extracts of mycelia of Antrodia cinnamomea (EMAC) in vitro and in vivo.
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Functional proteomic analysis of rice bran esterases/lipases and characterization of a novel recombinant esterase.
J. Agric. Food Chem.
PUBLISHED: 02-15-2011
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An esterase from rice ( Oryza sativa ) bran was identified on two-dimensional gel using 4-methylumbelliferyl butyrate as a substrate. The esterase cDNA (870 bp) encoded a 289 amino acid protein (designated OsEST-b) and was expressed in Escherichia coli . The molecular weight of recombinant OsEST-b (rOsEST-b) was 27 kDa, as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Biochemical characterization demonstrated that rOsEST-b was active over a broad temperature range (optimum at 60 °C) and preferred alkaline conditions (optimum at pH 9.0). The rOsEST-b showed maximum activity toward p-nitrophenyl butyrate (C(4)) among various p-nitrophenyl esters (C(4)-C(18)), indicating that rOsEST-b is an esterase for short-chain fatty acids. The kinetic parameters under optimal conditions were K(m) = 27.03 ?M, k(cat) = 49 s(-1), and k(cat)/K(m) = 1.81 s(-1) ?M(-1). The activity of rOsEST-b was not influenced by ethylenediaminetetraacetic acid, suggesting that it is not a metalloenzyme. The amino acid sequence analysis revealed that OsEST-b had a conserved pentapeptide esterase/lipase motif but that the essential active site serine (GXSXG) was replaced by cysteine (C). These results suggest that OsEST-b is distinct from traditional esterases/lipases and is a novel lipolytic enzyme in rice bran.
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A closed-loop brain computer interface for real-time seizure detection and control.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 11-25-2010
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The worldwide prevalence of epilepsy is approximately 1%, and 25% of epilepsy patients cannot be treated sufficiently by available therapies. Brain stimulation with closed-loop seizure control has recently been proposed as an innovative and effective alternative. In this paper, a portable closed-loop brain computer interface for seizure control was developed and shown with several aspects of advantages, including high seizure detection rate (92-99% during wake-sleep states), low false detection rate (1.2-2.5%), and small size. The seizure detection and electrical stimulation latency was not greater than 0.6 s after seizure onset. A wireless communication feature also provided flexibility for subjects freeing from the hassle of wires. Experimental data from freely moving rats supported the functional possibility of a real-time closed-loop seizure controller.
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Site-Specific Saturation Mutagenesis on Residues 132 and 450 of Candida rugosa LIP2 Enhances Catalytic Efficiency and Alters Substrate Specificity in Various Chain Lengths of Triglycerides and Esters.
J. Agric. Food Chem.
PUBLISHED: 09-27-2010
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The catalytic versatility of recombinant Candida rugosa LIP2 has been known to have potential applications in industry. In this study, site-specific saturation mutagenesis on residues L132 and G450 of recombinant LIP2 has been employed to investigate the impact of both residues on substrate specificity of LIP2. Point mutations on L132 and G450 were done separately using mutagenic degenerate primer sets containing 32 codons to generate two libraries of mutants in Pichia pastoris . Replacements of amino acid on these mutants were identified as L132A, L132I, G450S, and G450A. In lipase activity assay, L132A and L132I mutants showed a shift of preference from short- to medium-chain triglyceride, whereas G450S and G450A mutants retained preferences as compared to wild-type LIP2. Among mutants, G450A has the highest activity on tributyrin. However, hydrolysis of p-nitrophenyl (p-NP) esters with L132A, L132I, and G450S did not show differences of preferences over medium- to long-chain esters except in G450A, which prefers only medium-chain ester as compared to wild-type LIP2. All mutants showed an enhanced catalytic activity and higher optimal temperature and pH stability as compared to wild-type LIP2.
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Activation of calcium/calmodulin-dependent protein kinase IV and peroxisome proliferator-activated receptor ? coactivator-1? signaling pathway protects against neuronal injury and promotes mitochondrial biogenesis in the hippocampal CA1 subfield after tra
J. Neurosci. Res.
PUBLISHED: 08-28-2010
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Delayed neuronal cell death occurs in the vulnerable CA1 subfield of the hippocampus after transient global ischemia (TGI). We demonstrated previously, based on an experimental model of TGI, that the significantly increased content of oxidized proteins in hippocampal CA1 neuron was observed as early as 30 min after TGI, followed by augmentation of PGC-1? expression at 1 hr, as well as up-regulation of mitochondrial uncoupling protein 2 (UCP2) and superoxide dismutases 2 (SOD2). Using the same animal model, the present study investigated the role of calcium/calmodulin-dependent protein kinase IV (CaMKIV) and PGC-1? in delayed neuronal cell death and mitochondrial biogenesis in the hippocampus. In Sprague-Dawley rats, significantly increased expression of nuclear CaMKIV was noted in the hippocampal CA1 subfield as early as 15 min after TGI. In addition, the index of mitochondrial biogenesis, including a mitochondrial DNA-encoded polypeptide, cytochrome c oxidase subunit 1 (COX1), and mitochondrial number significantly increased in the hippocampal CA1 subfield 4 hr after TGI. Application bilaterally into the hippocampal CA1 subfield of an inhibitor of CaMKIV, KN-93, 30 min before TGI attenuated both CaMKIV and PGC-1? expression, followed by down-regulation of UCP2 and SOD2, decrease of COX1 expression and mitochondrial number, heightened protein oxidation, and enhanced hippocampal CA1 neuronal damage. This study provides correlative evidence for the neuroprotective cascade of CaMKIV/PGC-1? which implicates at least in part the mitochondrial antioxidants UCP2 and SOD2 as well as mitochondrial biogenesis in ischemic brain injury.
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Genes and biochemical characterization of three novel chlorophyllase isozymes from Brassica oleracea.
J. Agric. Food Chem.
PUBLISHED: 08-05-2010
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Three full length cDNAs (BoCLH1, 1140 bp; BoCLH2, 1104 bp; BoCLH3, 884 bp) encoding putative chlorophyllases were cloned from the cDNA pools of broccoli (Brassica oleracea) florets and characterized. The amino acid sequence analysis indicated that these three BoCLHs contained a highly conserved lipase motif (GXSXG). However, only BoCLH3 lacked the His residue which is the component of the catalytic triad (Ser-His-Asp). N-terminal sequences of BoCLH1 and BoCLH2 were predicted to have typical signal sequences for the chloroplast, whereas the plasma membrane-targeting sequence was identified in BoCLH3. The predicted molecular masses of BoCLH1, 2, and 3 were 34.7, 35.3, and 23.5 kDa, respectively. The recombinant BoCLHs were successfully expressed in Escherichia coli for the biochemical characterization. The recombinant BoCLH3 showed very low chlorophyllase activity possibly due to its incomplete catalytic triad. BoCLH1 and BoCLH2 showed significant differences in biochemical properties such as pH stability and temperature optimum. Kinetic analysis revealed that BoCLH1 preferably hydrolyzed Mg-free chlorophyll, while BoCLH2 hydrolyzed both chlorophyll and Mg-free chlorophyll at a similar level. Different characteristics between BoCLH1 and BoCLH2 implied that they may have different physiological functions in broccoli. The catalytic triad of recombinant BoCLH2 was identified as Ser141, His247, and Asp170 by site-directed mutagenesis. It suggested that the three broccoli chlorophyllase isozymes were serine hydrolases.
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Leucocyte apoptosis in patients with acute ischaemic stroke.
Clin. Exp. Pharmacol. Physiol.
PUBLISHED: 04-26-2010
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1. Inflammation and activated leucocytes are involved in the pathogenesis of acute ischaemic stroke. Leucocyte apoptosis is critical for the efficient resolution of inflammation. Little is known about the correlation between leucocyte apoptosis and acute ischaemic stroke (AIS). The objective of the present study was to evaluate the role of leucocyte apoptosis in patients with AIS. 2. Serial changes in leucocyte apoptosis and the apoptosis of leucocyte subsets (i.e. neutrophils, monocytes and lymphocytes), as determined by flow cytometry, were examined prospectively at various time-points in 50 patients with AIS and 50 controls using the APO 2.7 antibody. 3. Leucocyte apoptosis and the apoptosis of leucocyte subsets were significantly lower in stroke patients than in the control group (P < 0.01). The percentage apoptosis of total leucocytes and neutrophils was significantly lower in the group with large-artery disease than in the group with small-atery disease (P < 0.01). Leucocyte apoptosis was lowest during the acute stage of ischaemic stroke and increased thereafter. 4. Leucocyte apoptosis may reflect the inflammatory status after AIS. A better understanding of the mechanisms underlying leucocyte apoptosis in ischaemic stroke may lead to the development of new strategies to improve the outcome for stroke patients.
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Construction of chromosomally located T7 expression system for production of heterologous secreted proteins in Bacillus subtilis.
J. Agric. Food Chem.
PUBLISHED: 04-10-2010
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Bacillus subtilis is most commonly employed for secretion of recombinant proteins. To circumvent the problems caused by using plasmids, the T7 expression system known for its high efficiency was rebuilt in B. subtilis. Accordingly, a markerless and replicon-free method was developed for genomic insertion of DNAs. By the act of homologous recombination via the guide DNA, a suicidal vector carrying the gene of interest was integrated into genomic loci of bacteria. Removal of the inserted selection marker and replicon flanked by FRT sites was mediated by the FLP recombinase. By using the mentioned system, B. subtilis strain PT5 was constructed to harbor a genomic copy of the spac promoter-regulated T7 gene 1 located at wprA (encoding the cell wall-associated protease). Similarly, the T7 promoter-driven nattokinase or endoglucanase E1 of Thermomonospora fusca genes were also integrated into mpr (encoding an extracellular protease) of strain PT5. Consequently, the integrant PT5/Mmp-T7N or PT5/MT1-E1 resulted in a "clean" producer strain deprived of six proteases. After 24 h, the strain receiving induction was able to secret nattokinase and endoglucanase E1 with the volumetric activity reaching 10860 CU/mL and 8.4 U/mL, respectively. This result clearly indicates the great promise of the proposed approach for high secretion of recombinant proteins in B. subtilis.
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Cloning and characterization of the lanosterol 14alpha-demethylase gene from Antrodia cinnamomea.
J. Agric. Food Chem.
PUBLISHED: 03-26-2010
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Sterol 14alpha-demethylase (CYP51) is one of the key enzymes for sterol biosynthesis in fungi; it is widely distributed in all members of the cytochrome P450 superfamily. In this study, AcCyp51, encoding a cytochrome P450 sterol 14alpha-demethylase, was obtained from the sequences of EST libraries of Antrodia cinnamomea by using 5 RACE and genome walking methods. The open reading frame of AcCyp51 is 1635 bp and encodes 544 amino acids. The recombinant protein of AcCYP51 fused with glutathione-S-transferase from Escherichia coli revealed the demethylating activity by using lanosterol as substrate and GC-MS analysis. Gene expression levels of AcCYP51 were higher in natural basidiomes than in other cell types. Transcription of AcCYP51 increased in various culture conditions including adding squalene, lanosterol, itroconazole, and oleic acid as inducers. These reveal the important functions of AcCYP51 in basidiomatal formation and suggest that it might participate in other biological processes.
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Simultaneous production of trehalose, bioethanol, and high-protein product from rice by an enzymatic process.
J. Agric. Food Chem.
PUBLISHED: 02-06-2010
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Rice is a starch-rich raw material that can be used for trehalose production. It can be hydrolyzed with alpha-amylase, beta-amylase, and pullulanase to produce high-maltose content of rice saccharified solution for bioconversion of maltose into trehalose by trehalose synthase (TSase). For this purpose, an efficient enzymatic procedure has been successfully developed to simultaneously produce value-added trehalose, bioethanol, and high-protein product from rice as substrate. The highest maltose yield produced from the liquefied rice starch hydrolysate was 82.4 +/- 2.8% at 50 degrees C and pH 5.0 for 21-22 h. The trehalose conversion rate can reach at least 50% at 50 degrees C and pH 5.0 for 20-24 h by a novel thermostable recombinant Picrophilus torridus trehalose synthase (PTTS). All residual sugar, except trehalose, can be fully hydrolyzed by glucoamylase into glucose for further bioethanol production. The insoluble byproduct containing high yields of protein (75.99%) and dietary fiber (14.01%) can be processed as breakfast cereal product, health food, animal forage, etc. The conversion yield of bioethanol was about 98% after 64 h of fermentation time by Saccharomyces cerevisiae without any artificial culture solution addition. Ethanol can easily be separated from trehalose by distillation with a high recovery yield and purity of crystalline trehalose of 92.5 +/- 8.7% and 92.3%, respectively.
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Antrocamphin A, an anti-inflammatory principal from the fruiting body of Taiwanofungus camphoratus , and its mechanisms.
J. Agric. Food Chem.
PUBLISHED: 02-05-2010
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The fungus Taiwanofungus camphoratus is commonly used for medicinal purposes in Taiwan. It is used as a detoxicant for food poisoning and considered to be a precious folk medicine for hepatoprotection and anti-inflammation. In this study, a lipopolysaccaride (LPS)-challenged ICR mouse acute inflammation model and a LPS-induced macrophage model were used to evaluate the anti-inflammatory activity of T. camphoratus. Ethanol extract of T. camphoratus significantly inhibited expression of iNOS and COX-2 in the liver of LPS-challenged acute inflammatory mice. The ethyl acetate fraction and its isolated compound, antrocamphin A, significantly suppressed nitrite/nitrate concentration in LPS-challenged RAW 264.7 cells. Antrocamphin A showed potent anti-inflammatory activity by suppressing pro-inflammatory molecule release via the down-regulation of iNOS and COX-2 expression through the NF-kappaB pathway. This study, therefore, first demonstrates the bioactive compound of T. camphoratus and illustrates the mechanism by which it confers its anti-inflammatory activity.
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Dysregulation of Ca2+ movement in platelets from patients with acute ischaemic stroke.
Clin. Exp. Pharmacol. Physiol.
PUBLISHED: 12-16-2009
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1. Platelets play a pivotal role during acute ischaemic stroke. An increase in cytosolic Ca(2+) concentrations ([Ca(2+)](i)) triggers intracellular signal transduction, leading to platelet aggregation and thrombosis. In the present study, we examined the differences between platelets from acute ischaemic stroke patients and at-risk controls in terms of the increase in platelet [Ca(2+)](i). 2. Thirty-one patients with acute ischaemic stroke and 27 at-risk controls were enrolled in the present study. Platelet [Ca(2+)](i) was measured using the fluorescent dye fura-2 after stimulation with 100 micromol/L arachidonic acid (AA), 10 micromol/L ADP, 1 micromol/L platelet-activation factor (PAF) and 0.1 U/mL thrombin. 3. Basal [Ca(2+)](i) was higher in the stroke group compared with at-risk controls, irrespective of the presence or absence of extracellular Ca(2+). In Ca(2+)-containing medium, both PAF and ADP, but not AA and thrombin, significantly increased platelet [Ca(2+)](i) in the stroke group compared with the at-risk controls. However, in Ca(2+)-free medium, only PAF significantly increased platelet [Ca(2+)](i) in the stroke group compared with the at-risk controls. Basal [Ca(2+)](i) and PAF-induced platelet [Ca(2+)](i) increases were still higher in the stroke group at the subacute stage than in the at-risk controls. 4. The results of the present study provide direct evidence that Ca(2+) signalling in platelets from acute ischaemic stroke patients was altered in response to particular stimuli. The dysregulation of Ca(2+) movement in platelets may persist up to the subacute stage of ischaemic stroke.
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Treatment with deferiprone for iron overload alleviates bone marrow failure in a Fanconi anemia patient.
Hemoglobin
PUBLISHED: 10-10-2009
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Fanconi anemia (FA) is a rare inherited disorder characterized by congenital abnormalities, progressive bone marrow failure and cancer susceptibility. There are no reports in the literature about a specific therapy effective in treating the progressive bone marrow failure of FA except for hematopoietic stem cell transplantation (HSCT). A FA patient started to receive deferiprone (L1) therapy due to iron overload. We report here that the white blood cell counts, hemoglobin (Hb) levels and platelet counts were significantly higher during the L1-treated period than when without L1 therapy. Therefore, L1 therapy may be worth considering for FA patients who cannot undergo HSCT.
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Sequential transplants for respective relapse of Hodgkin disease and hemophagocytic lymphohistiocytosis: a treatment dilemma.
J. Pediatr. Hematol. Oncol.
PUBLISHED: 09-17-2009
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The association of hemophagocytic lymphohistiocytosis (HLH) with Hodgkin disease (HD) seems to be uncommon. A 9-year-old boy, diagnosed with HD-HLH, received chemotherapy and remained in complete remission for 21 months. Then the patient received the first autologous transplant and unfortunately died due to multiorgan failure after the second allogeneic transplant because of sequentially respective relapse of HD and HLH. The recurrence of HLH with a high Epstein-Barr virus load but without relapse of HD in the patient suggests that Epstein-Barr virus may have a major pathogenetic role in the specific disorder HLH-HD. Detailed reports relating to HLH-HD were also reviewed.
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Compound mutations in human anion exchanger 1 are associated with complete distal renal tubular acidosis and hereditary spherocytosis.
Kidney Int.
PUBLISHED: 07-22-2009
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Missense, nonsense, and frameshift mutations in the human anion exchanger 1 have been associated with inherited distal renal tubular acidosis and hereditary spherocytosis. These two disorders, however, are almost always mutually exclusive. We have found an important and unusual exception: a novel combination of heterozygous E522K and G701D mutations in the anion exchanger 1 manifested as complete distal renal tubular acidosis and severe hereditary spherocytosis in an affected patient. Analysis of protein trafficking and subcellular localization of the wild-type kidney isoform of human anion exchanger 1 and these mutants transfected into MDCK cells showed they formed homodimers or heterodimers with each other. Homodimers of the wild-type and E522K mutant were found at the plasma membrane, whereas the G701D mutant largely remained in the cytoplasm. Heterodimers of either E522K or G701D and the wild-type exchanger were located in the plasma membrane, whereas E522K/G701D heterodimers remained in the cytoplasm. Our study shows that the compound E522K/G701D mutation of human anion exchanger 1 causes a trafficking defect in kidney cells, and this may explain the complete distal renal tubular acidosis of the patient.
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Functional role of a non-active site residue Trp(23) on the enzyme activity of Escherichia coli thioesterase I/protease I/lysophospholipase L(1).
Biochim. Biophys. Acta
PUBLISHED: 06-08-2009
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Escherichia coli possesses a versatile protein with the enzyme activities of thioesterase I, protease I, and lysophospholipase L(1). The protein is dubbed as TAP according to the chronological order of gene discovery (TesA/ApeA/PldC). Our previous studies showed that TAP comprises the catalytic triad Ser(10), Asp(154), and His(157) as a charge relay system, as well as Gly(44) and Asn(73) residues devoted to oxyanion hole stabilization. Geometrically, about 10 A away from the enzyme catalytic cleft, Trp(23) showed a stronger resonance shift than the backbone amide resonance observed in the nuclear magnetic resonance (NMR) analyses. In the present work, we conducted site-directed mutagenesis to change Trp into alanine (Ala), phenylalanine (Phe), or tyrosine (Tyr) to unveil the role of the Trp(23) indole ring. Biochemical analyses of the mutant enzymes in combination with TAPs three-dimensional structures suggest that by interlinking the residues participating in this catalytic machinery, Trp(23) could effectively influence substrate binding and the following turnover number. Moreover, it may serve as a contributor to both H-bond and aromatic-aromatic interaction in maintaining the cross-link within the interweaving framework of protein.
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A novel application of the S-transform in removing powerline interference from biomedical signals.
Physiol Meas
PUBLISHED: 04-08-2009
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Powerline interference always disturbs recordings of biomedical signals. Numerous methods have been developed to reduce powerline interference. However, most of these techniques not only reduce the interference but also attenuate the 60 Hz power of the biomedical signals themselves. In the present study, we applied the S-transform, which provides an absolute phase of each frequency in a multi-resolution time-frequency analysis, to reduce 60 Hz interference. According to results from an electrocardiogram (ECG) to which a simulated 60 Hz noise was added, the S-transform de-noising process restored a power spectrum identical to that of the original ECG coincident with a significant reduction in the 60 Hz interference. Moreover, the S-transform de-noised the signal in an intensity-independent manner when reducing the 60 Hz interference. In both a real ECG signal from the MIT database and natural brain activity contaminated with 60 Hz interference, the S-transform also displayed superior merit to a notch filter in the aspect of reducing noise and preserving the signal. Based on these data, a novel application of the S-transform for removing powerline interference is established.
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Biocatalysis for the production of carbohydrate esters.
N Biotechnol
PUBLISHED: 04-06-2009
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Carbohydrate fatty acid esters are nonionic biosurfactants, which can be synthesized from the esterification of mono- or oligosaccharides by enzymatic catalysis. These esters are increasingly used as important commodity chemicals, such as low calorific sweeteners and biosurfactants in food, pharmaceutical and cosmetic industries. Recently, some of the ester derivatives have shown their therapeutic potential with antitumor activity, plant growth inhibition and antibiotic activities, which became one of the hot subjects for various biological processes. However, this potential has not been fully explored because the production of oligoesters (e.g. di-, tri- and tetra-) of sugars is a difficult problem in organic chemistry because of the abundance of hydroxyl groups in sugar molecules and the similar reactivity of most of them. Solvent engineering can be employed to improve the yields of sugar esters by using biocatalytic reactions. Protein engineering is useful in improving the catalytic efficiency, thermostability and pH stability of biocatalysts for enzymatic synthesis of sugar ester. The use of recombinant DNA technology to produce large quantities of enzymes in a heterologous host will lower the overall production cost. The cloning of key enzyme genes for the carbohydrate esters biosynthesis pathway and overexpressing these genes using strong promoters in either plants or microorganisms through metabolic engineering will be also discussed in this review.
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The value of leukocyte adhesion molecules in patients after ischemic stroke.
J. Neurol.
PUBLISHED: 03-17-2009
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Leukocyte recruitment and inflammatory response play an important patho-physiologic role after cerebral ischemia. This study aimed to evaluate whether leukocyte adhesion molecules can predict clinical outcome in patients after ischemic stroke. We prospectively examined serial changes in p-selectin glycoprotein ligand-1 (PSGL-1), macrophage antigen-1 (Mac-1), and lymphocyte function-associated antigen-1 (LFA-1) expression by leukocyte subsets using flow cytometry at various time points in 65 acute ischemic stroke patients and 60 controls. PSGL-1 expression on neutrophils and monocytes was significantly higher from day 1 to 90 after stroke as compared with control subjects (p < 0.05). The expression of monocyte Mac-1, LFA-1, and neutrophil Mac-1 were also significantly increased on days 1 and 7 after stroke than in control subjects (p < 0.05). Neutrophil PSGL-1 expression on day 1 was significantly higher in patients with early neurologic deterioration (END) (p < 0.01). Monocyte Mac-1 expression positively correlated with National Institutes of Health Stroke Scale (NIHSS) scores on admission (p = 0.013, gamma = 0.318). Underlying disease of diabetes mellitus and NIHSS score on admission were independently associated with 3-month outcome. The expressions of leukocyte adhesion molecules on admission are significantly increased in patients with acute ischemic stroke. This study shows that higher neutrophil PSGL-1 expression on admission may imply a higher risk for END and that monocyte Mac-1 expression on admission reflects the severity of ischemic stroke on admission.
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Structure of the alkalohyperthermophilic Archaeoglobus fulgidus lipase contains a unique C-terminal domain essential for long-chain substrate binding.
J. Mol. Biol.
PUBLISHED: 02-02-2009
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Several crystal structures of AFL, a novel lipase from the archaeon Archaeoglobus fulgidus, complexed with various ligands, have been determined at about 1.8 A resolution. This enzyme has optimal activity in the temperature range of 70-90 degrees C and pH 10-11. AFL consists of an N-terminal alpha/beta-hydrolase fold domain, a small lid domain, and a C-terminal beta-barrel domain. The N-terminal catalytic domain consists of a 6-stranded beta-sheet flanked by seven alpha-helices, four on one side and three on the other side. The C-terminal lipid binding domain consists of a beta-sheet of 14 strands and a substrate covering motif on top of the highly hydrophobic substrate binding site. The catalytic triad residues (Ser136, Asp163, and His210) and the residues forming the oxyanion hole (Leu31 and Met137) are in positions similar to those of other lipases. Long-chain lipid is located across the two domains in the AFL-substrate complex. Structural comparison of the catalytic domain of AFL with a homologous lipase from Bacillus subtilis reveals an opposite substrate binding orientation in the two enzymes. AFL has a higher preference toward long-chain substrates whose binding site is provided by a hydrophobic tunnel in the C-terminal domain. The unusually large interacting surface area between the two domains may contribute to thermostability of the enzyme. Two amino acids, Asp61 and Lys101, are identified as hinge residues regulating movement of the lid domain. The hydrogen-bonding pattern associated with these two residues is pH dependent, which may account for the optimal enzyme activity at high pH. Further engineering of this novel lipase with high temperature and alkaline stability will find its use in industrial applications.
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Levels and value of platelet activation markers in different subtypes of acute non-cardio-embolic ischemic stroke.
Thromb. Res.
PUBLISHED: 01-21-2009
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Platelet activation and its interaction with leukocytes are important in the pathophysiology of ischemic stroke. This study aimed to evaluate the value of platelet activation and platelet-leukocyte interaction in different subtypes of acute, non-cardio-embolic ischemic stroke.
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Integrated biocatalytic process for trehalose production and separation from rice hydrolysate using a bioreactor system.
Food Chem
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Rice starch can be hydrolyzed into maltose for trehalose bioconversion by enzymatic methods. In this study, we have successfully established an efficient production system for our recombinant PTTS in large scale. Three bio-treatments were developed to simplify the separation and purification of trehalose from complex rice saccharified liquid. The trehalose conversion rate of 64.63±4.05% at 30 °C can be reached using rice hydrolysate as the substrate in a 5l fermentor system. By 1% of raw material koji fermentation, the highest concentration of bioethanol (3.61±0.07%) was obtained at 30 °C for 36 h. After 12h of reaction time, the gluconic acid (24.47±0.33 mM) was successfully produced by glucose oxidase (40 U/g rice) using residual glucose as a substrate. After the batch/continuous ionic exchange process, the trehalose can be successfully separated, crystallized and identified as 92.6±0.02% purity and 94.2% of the recovery yield, respectively.
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Enzymatic processes for the purification of trehalose.
Biotechnol. Prog.
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A dual-enzyme process aiming at facilitating the purification of trehalose from maltose is reported in this study. Enzymatic conversion of maltose to trehalose usually leads to the presence of significant amount of glucose, by-product of the reaction, and unreacted maltose. To facilitate the separation of trehalose from glucose and unreacted maltose, sequential conversion of maltose to glucose and glucose to gluconic acid under the catalysis of glucoamylase and glucose oxidase, respectively, is studied. This study focuses on the hydrolysis of maltose with immobilized glucoamylase on Eupergit® C and CM Sepharose. CM Sepharose exhibited a higher protein adsorption capacity, 49.35 ± 1.43 mg/g, and was thus selected as carrier for the immobilization of glucoamylase. The optimal reaction temperature and reaction pH of the immobilized glucoamylase for maltose hydrolysis were identified as 40°C and 4.0, respectively. Under such conditions, the unreacted maltose in the product stream of trehalose synthase-catalyzed reaction was completely converted to glucose within 35 min, without detectable trehalose degradation. The conversion of maltose to glucose could be maintained at 0.92 even after 80 cycles in repeated-batch operations. It was also demonstrated that glucose thus generated could be readily oxidized into gluconic acid, which can be easily separated from trehalose. We thus believe the proposed process of maltose hydrolysis with immobilized glucoamylase, in conjunction with trehalose synthase-catalyzed isomerization and glucose oxidase-catalyzed oxidation, is promising for the production and purification of trehalose on industrial scales.
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Lamotrigine ameliorates seizures and psychiatric comorbidity in a rat model of spontaneous absence epilepsy.
Epilepsia
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? Lamotrigine (LTG) is an effective clinical treatment for epilepsy associated with absence seizures. However, the impact of LTG administration in studies employing various animal models of epilepsy remains controversial. This study aimed to clarify the outcomes of LTG treatment on absence seizures and comorbid anxiety and depression disorders in Long-Evans rats with spontaneous spike-wave discharges (SWDs).
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Multifunctionality and diversity of GDSL esterase/lipase gene family in rice (Oryza sativa L. japonica) genome: new insights from bioinformatics analysis.
BMC Genomics
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GDSL esterases/lipases are a newly discovered subclass of lipolytic enzymes that are very important and attractive research subjects because of their multifunctional properties, such as broad substrate specificity and regiospecificity. Compared with the current knowledge regarding these enzymes in bacteria, our understanding of the plant GDSL enzymes is very limited, although the GDSL gene family in plant species include numerous members in many fully sequenced plant genomes. Only two genes from a large rice GDSL esterase/lipase gene family were previously characterised, and the majority of the members remain unknown. In the present study, we describe the rice OsGELP (Oryza sativa GDSL esterase/lipase protein) gene family at the genomic and proteomic levels, and use this knowledge to provide insights into the multifunctionality of the rice OsGELP enzymes.
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Strategy for Stable and High-Level Expression of Recombinant Trehalose Synthase in Escherichia coli.
J. Agric. Food Chem.
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Trehalose is a nonreducing disaccharide and has a wide range of applications in food and biorelated industry. This sugar can be synthesized from maltose in one step by trehalose synthase. In this study, we attempted to overproduce trehalose synthase from Picrophilus torridus (PTTS), a thermoacidophilic archaea, in Escherichia coli . However, overproduction of PTTS was hampered when the T7 promoter-driven PTTS gene (PT7-PTTS) on a multicopy plasmid was employed in E. coli . The factors limiting PTTS production were identified in a systematic way, including the codon bias, plasmid instability, a redundant gene copy, a high basal level of PTTS, and metabolic burden resulting from the mutlicopy plasmid DNA and antibiotics. To overcome these difficulties, an E. coli strain was developed with insertion of PT7-PTTS into the chromosome and enhanced expression of genomic argU tRNA and ileX tRNA genes. Without the selective pressure, the constructed producer strain was able to produce a stable and high-level production of recombinant PTTS. Overall, we proposed a simple and effective method to address the issue that is most commonly raised in overproduction of heterologous proteins by E. coli .
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Arabidopsis ENDO2: its catalytic role and requirement of N-glycosylation for function.
J. Agric. Food Chem.
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The Arabidopsis thaliana At1g68290 gene encoding an endonuclease was isolated and designated ENDO2, which was cloned into a binary vector to overexpress ENDO2 with a C-terminal 6 × His-tag in A. thaliana. Our Arabidopsis transgenic lines harboring 35SP::ENDO2 produced stable active enzyme with high yield. The protein was affinity purified from transgenic plants, and its identity was confirmed by liquid chromatography-mass spectrometry and automatic Edman degradation. ENDO2 enzyme digests RNA, ssDNA, and dsDNA, with a substrate preference for ssDNA and RNA. The activity toward ssDNA (361.7 U/mg) is greater than its dsDNase activity (14.1 U/mg) at neutral pH. ENDO2 effectively cleaves mismatch regions in heteroduplex DNA containing single base pair mismatches or insertion/deletion bases and can be applied to high-throughput detection of single base mutation. Our data also validated that the removal of sugar groups from ENDO2 strongly affects its enzymatic stability and activity.
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EEG correlates of haptic feedback in a visuomotor tracking task.
Neuroimage
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This study investigates the temporal brain dynamics associated with haptic feedback in a visuomotor tracking task. Haptic feedback with deviation-related forces was used throughout tracking experiments in which subjects behavioral responses and electroencephalogram (EEG) data were simultaneously measured. Independent component analysis was employed to decompose the acquired EEG signals into temporally independent time courses arising from distinct brain sources. Clustering analysis was used to extract independent components that were comparable across participants. The resultant independent brain processes were further analyzed via time-frequency analysis (event-related spectral perturbation) and event-related coherence (ERCOH) to contrast brain activity during tracking experiments with or without haptic feedback. Across subjects, in epochs with haptic feedback, components with equivalent dipoles in or near the right motor region exhibited greater alpha band power suppression. Components with equivalent dipoles in or near the left frontal, central, left motor, right motor, and parietal regions exhibited greater beta-band power suppression, while components with equivalent dipoles in or near the left frontal, left motor, and right motor regions showed greater gamma-band power suppression relative to non-haptic conditions. In contrast, the right occipital component cluster exhibited less beta-band power suppression in epochs with haptic feedback compared to non-haptic conditions. The results of ERCOH analysis of the six component clusters showed that there were significant increases in coherence between different brain networks in response to haptic feedback relative to the coherence observed when haptic feedback was not present. The results of this study provide novel insight into the effects of haptic feedback on the brain and may aid the development of new tools to facilitate the learning of motor skills.
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A novel highly active recombinant glutaredoxin from Chlorella sorokiniana T-89.
J. Agric. Food Chem.
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Glutaredoxin (Grx) is a thiol/disulfide oxidoreductase that maintains the cellular thiol/disulfide ratio. A 321 bp cDNA fragment encoding a putative Grx (named CsT-89Grx) was cloned from heat-tolerant Chlorella sorokiniana T-89 and expressed in an Escherichia coli system. The sequence analysis of CsT-89Grx and site-directed mutations showed that the putative active site within the CPYC motif belonged to the dithiol superfamily. The biochemical property analyses showed that the optimal pH and temperature of CsT-89Grx are pH 8.5 and 50 ?C, respectively. The activity of CsT-89Grx showed high thermal stability (retained 70% activity at 80 ?C for 30 min) and broad pH stability (retained over 70% activity for 1 h) ranging from pH 3 to 11. The kinetic parameter kcat/Km was 20982 min-1 mM-1, which suggested that CsT-89Grx exhibited the highest catalytic efficiency in reducing disulfide bond among all the Grx reported in the related literature and is therefore potentially useful for industrial applications.
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