5 research outputs found

    Acetylcholinesterase Liquid Crystal Biosensor Based on Modulated Growth of Gold Nanoparticles for Amplified Detection of Acetylcholine and Inhibitor

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    A novel acetylcholinesterase (AChE) liquid crystal (LC) biosensor based on enzymatic growth of gold nanoparticles (Au NPs) has been developed for amplified detection of acetylcholine (ACh) and AChE inhibitor. In this method, AChE mediates the hydrolysis of acetylthiocholine (ATCl) to form thiocholine, and the latter further reduces AuCl<sub>4</sub><sup>–</sup> to Au NPs without Au nanoseeds. This process, termed biometallization, leads to a great enhancement in the optical signal of the LC biosensor due to the large size of Au NPs, which can greatly disrupt the orientational arrangement of LCs. On the other hand, the hydrolysis of ATCl is inhibited in the presence of ACh or organophosphate pesticides (OPs, a AChE inhibitor), which will decrease the catalytic growth of Au NPs and, as a result, reduce the orientational response of LCs. On the basis of such an inhibition mechanism, the AChE LC biosensor can be used as an effective way to realize the detection of ACh and AChE inhibitors. The results showed that the AChE LC biosensor was highly sensitive to ACh with a detection limit of 15 μmol/L and OPs with a detection limit of 0.3 nmol/L. This study provides a simple and sensitive AChE LC biosensing approach and offers effective signal enhanced strategies for the development of enzyme LC biosensors

    Scapairrins A–Q, Labdane-Type Diterpenoids from the Chinese Liverwort <i>Scapania irrigua</i> and Their Cytotoxic Activity

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    Seventeen new labdane-type diterpenoids, scapairrins A–Q (<b>1</b>–<b>17</b>), including six pairs of diastereoisomers, and three known analogues (<b>18</b>–<b>20</b>) were isolated from the Chinese liverwort <i>Scapania irrigua</i>. The structures of <b>1</b>–<b>17</b> were determined based on a combination of the analysis of their MS and NMR spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Cytotoxicity testing showed that compounds <b>7</b>–<b>10</b> exhibited inhibitory activities against a small panel of human cancer cell lines

    Ophiosphaerellins A–I, Polyketide-Derived Compounds from the Endolichenic Fungus Ophiosphaerella korrae

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    Ophiosphaerellins A–I (<b>1</b>–<b>9</b>), the first example of bicyclo[4.1.0]­heptenones, as well as their biosynthetic relatives ophiosphaerekorrins A–B (<b>10</b>–<b>11</b>) were isolated from the endolichenic fungus Ophiosphaerella korrae. Biosynthetically, they were derived from the polyketide pathway, and their absolute configurations were determined on the basis of the combination analysis of spectral data, circular dichroism calculations, and single-crystal X-ray diffraction measurement. Preliminary test with thin-layer chromatography bioautography found that this type of compounds showed moderate acetylcholinesterase (AChE) inhibitory effects

    Ophiosphaerellins A–I, Polyketide-Derived Compounds from the Endolichenic Fungus Ophiosphaerella korrae

    No full text
    Ophiosphaerellins A–I (<b>1</b>–<b>9</b>), the first example of bicyclo[4.1.0]­heptenones, as well as their biosynthetic relatives ophiosphaerekorrins A–B (<b>10</b>–<b>11</b>) were isolated from the endolichenic fungus Ophiosphaerella korrae. Biosynthetically, they were derived from the polyketide pathway, and their absolute configurations were determined on the basis of the combination analysis of spectral data, circular dichroism calculations, and single-crystal X-ray diffraction measurement. Preliminary test with thin-layer chromatography bioautography found that this type of compounds showed moderate acetylcholinesterase (AChE) inhibitory effects

    Ophiosphaerellins A–I, Polyketide-Derived Compounds from the Endolichenic Fungus Ophiosphaerella korrae

    No full text
    Ophiosphaerellins A–I (<b>1</b>–<b>9</b>), the first example of bicyclo[4.1.0]­heptenones, as well as their biosynthetic relatives ophiosphaerekorrins A–B (<b>10</b>–<b>11</b>) were isolated from the endolichenic fungus Ophiosphaerella korrae. Biosynthetically, they were derived from the polyketide pathway, and their absolute configurations were determined on the basis of the combination analysis of spectral data, circular dichroism calculations, and single-crystal X-ray diffraction measurement. Preliminary test with thin-layer chromatography bioautography found that this type of compounds showed moderate acetylcholinesterase (AChE) inhibitory effects
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