5 research outputs found
Acetylcholinesterase Liquid Crystal Biosensor Based on Modulated Growth of Gold Nanoparticles for Amplified Detection of Acetylcholine and Inhibitor
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
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
Ophiosphaerellins
A–I (<b>1</b>–<b>9</b>), the first example
of bicyclo[4.1.0]Âheptenones, 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
Ophiosphaerellins
A–I (<b>1</b>–<b>9</b>), the first example
of bicyclo[4.1.0]Âheptenones, 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
Ophiosphaerellins
A–I (<b>1</b>–<b>9</b>), the first example
of bicyclo[4.1.0]Âheptenones, 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