157 research outputs found

    Antioxidation activity and total phenolic contents of various Toona sinensis extracts

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    Products Processing Division, LRI, COA, Tainan, Taiwan. Accepted 1 August, 2012 The purpose of this study was to analyze the antioxidation activities and total phenolic contents of Toona sinensis. An extractive method of the antioxidant activities of local T. sinensis leaf extracts and various antioxidation models were analyzed. The effects of various solvent concentrations to extract the T. sinensis leaf on the antioxidation activity were compared. The results showed that the T. sinensis leaf extracts of various solvent concentrations had good antioxidant activities. The chelating abilities of ferrous ion in the T. sinensis leaf extracts obtained from various solvent concentrations were above 80%. It is concluded that T. sinensis leaf extracts could be used as biopreservatives of food products. The total antioxidant activities, chelating abilities of ferrous ions and reducing capacities of the T. sinensis leaf extracts might provide a substitute for a natural antioxidant.Keywords: Antioxidative activity, bio-preservatives, extracts, Toona sinensi

    Novel Codon-optimization Genes Encoded in Chlorella for Triacylglycerol Accumulation

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    AbstractMicroalgae have been recognized as one of the potential resources for biodiesel production based on its fast growth or its high total lipid content depending on species. Expression of Kennedy pathway genes, which encodes GPAT, LPAAT, PAP, and DGAT for increasing the metabolic flux towards the TAG storage in Chlorella sp. from 20 to 46 wt% and total lipid accumulation from 35 to 60wt.% corresponding to each specific gene combination under autotrophy, compare to the wild type (vector only). The highest TAG content was found in cells expressing a quadruple-gene construct (GPAT-LPAAT-PAP-DGAT) in the Kennedy pathway, corresponding to 46wt.% of TAG and 60wt.% of total lipid content. This work provides the optimization of TAG production in Chlorella sp. can be achieved by manipulating the selected genes, in turns making commercially producing biodiesel practical

    The discovery of potential acetylcholinesterase inhibitors: A combination of pharmacophore modeling, virtual screening, and molecular docking studies

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    <p>Abstract</p> <p>Background</p> <p>Alzheimer's disease (AD) is the most common cause of dementia characterized by progressive cognitive impairment in the elderly people. The most dramatic abnormalities are those of the cholinergic system. Acetylcholinesterase (AChE) plays a key role in the regulation of the cholinergic system, and hence, inhibition of AChE has emerged as one of the most promising strategies for the treatment of AD.</p> <p>Methods</p> <p>In this study, we suggest a workflow for the identification and prioritization of potential compounds targeted against AChE. In order to elucidate the essential structural features for AChE, three-dimensional pharmacophore models were constructed using Discovery Studio 2.5.5 (DS 2.5.5) program based on a set of known AChE inhibitors.</p> <p>Results</p> <p>The best five-features pharmacophore model, which includes one hydrogen bond donor and four hydrophobic features, was generated from a training set of 62 compounds that yielded a correlation coefficient of R = 0.851 and a high prediction of fit values for a set of 26 test molecules with a correlation of R<sup>2 </sup>= 0.830. Our pharmacophore model also has a high Güner-Henry score and enrichment factor. Virtual screening performed on the NCI database obtained new inhibitors which have the potential to inhibit AChE and to protect neurons from Aβ toxicity. The hit compounds were subsequently subjected to molecular docking and evaluated by consensus scoring function, which resulted in 9 compounds with high pharmacophore fit values and predicted biological activity scores. These compounds showed interactions with important residues at the active site.</p> <p>Conclusions</p> <p>The information gained from this study may assist in the discovery of potential AChE inhibitors that are highly selective for its dual binding sites.</p

    Uroplakin IIIb, a urothelial differentiation marker, dimerizes with uroplakin Ib as an early step of urothelial plaque assembly

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    Urothelial plaques consist of four major uroplakins (Ia, Ib, II, and III) that form two-dimensional crystals covering the apical surface of urothelium, and provide unique opportunities for studying membrane protein assembly. Here, we describe a novel 35-kD urothelial plaque-associated glycoprotein that is closely related to uroplakin III: they have a similar overall type 1 transmembrane topology; their amino acid sequences are 34% identical; they share an extracellular juxtamembrane stretch of 19 amino acids; their exit from the ER requires their forming a heterodimer with uroplakin Ib, but not with any other uroplakins; and UPIII-knockout leads to p35 up-regulation, possibly as a compensatory mechanism. Interestingly, p35 contains a stretch of 80 amino acid residues homologous to a hypothetical human DNA mismatch repair enzyme-related protein. Human p35 gene is mapped to chromosome 7q11.23 near the telomeric duplicated region of Williams-Beuren syndrome, a developmental disorder affecting multiple organs including the urinary tract. These results indicate that p35 (uroplakin IIIb) is a urothelial differentiation product structurally and functionally related to uroplakin III, and that p35–UPIb interaction in the ER is an important early step in urothelial plaque assembly

    MicroRNA-31 is required for astrocyte specification

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    Previously, we determined microRNA-31 (miR-31) is a noncoding tumor suppressive gene frequently deleted in glioblastoma (GBM); miR-31 suppresses tumor growth, in part, by limiting the activity of NF-κB. Herein, we expand our previous studies by characterizing the role of miR-31 during neural precursor cell (NPC) to astrocyte differentiation. We demonstrate that miR-31 expression and activity is suppressed in NPCs by stem cell factors such as Lin28, c-Myc, SOX2 and Oct4. However, during astrocytogenesis, miR-31 is induced by STAT3 and SMAD1/5/8, which mediate astrocyte differentiation. We determined miR-31 is required for terminal astrocyte differentiation, and that the loss of miR-31 impairs this process and/or prevents astrocyte maturation. We demonstrate that miR-31 promotes astrocyte development, in part, by reducing the levels of Lin28, a stem cell factor implicated in NPC renewal. These data suggest that miR-31 deletions may disrupt astrocyte development and/or homeostasis
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