2,291 research outputs found
Anti-proliferation and apoptosis effects of Camellia nitidissima C. W. Chi extract on A549 lung cancer cells
Purpose: To investigate the effect of Camellia nitidissima C. W. Chi extract (CNCE) on apoptosis and proliferation in A549 human lung cancer cells.Methods: Inverted microscope was used to examine morphological changes in A549 cells after exposure to CNCE. Trypan blue staining of living cells was applied to construct the cell growth curve after treatment with varying concentrations of CNCE. The influence of CNCE on cell proliferation, apoptosis and cell cycle were determined by MTT assay. The protein expressions of key apoptosisrelated enzymes were evaluated by immuno-cytochemical method.Results: CNCE inhibited the growth of A549 lung cancer cells at the concentration range of 20 - 160 μg/mL. Flow cytometry showed that CNCE induced apoptosis in the A549 cells. The proportion of cells in G0/G1-phase increased significantly (p < 0.01), while the proportion of cells in S-phase and G2/Mphase decreased correspondingly, indicating that the cells were in G0/G1-phase arrest. Cell cycle arrest and apoptosis-inducing effect gradually increased with increase in CNCE concentration. With increasing concentrations of CNCE, there were significant increases in the expressions of caspase-3 (p < 0.05), caspase-8 (p < 0.01) and caspase-9 (p < 0.05), and significant decreases in Ki-67 (p < 0.01) and p21 ras protein (p < 0.01).Conclusion: CNCE exerts significant inhibitory effect on the proliferation of A549 lung cancer cells, and therefore can potentially be developed for the treatment of lung cancer.Keywords: Camellia nitidissima, Antitumor activity, Lung cancer, Apoptosis, Cell cycle arrest, Caspas
Disorder effects on the quantum coherence of a many-boson system
The effects of disorders on the quantum coherence for many-bosons are studied
in a double well model. For the ground state, the disorder enhances the quantum
coherence. In the deep Mott regime, dynamical evolution reveals periodical
collapses and revivals of the quantum coherence which is robust against the
disorder. The average over variations in both the on-site energy and the
interaction reveals a beat phenomenon of the coherence-decoherence oscillation
in the temporal evolution.Comment: 4 figure
Separation and Purification of Two Flavone Glucuronides from Erigeron multiradiatus (Lindl.) Benth with Macroporous Resins
Scutellarein-7-O-β-D-glucuronide (SG) and apigenin-7-O-β-D-glucuronide (AG) are two major bioactive constituents with known pharmacological effects in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141, and D160 have been evaluated. The results confirmed that D141 resin offered the best adsorption and desorption capacities and the highest desorption ratio for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin under optimal ethanol conditions and fitted well to the Freundlich and Langmuir models (R2 > 0.95). Dynamic adsorption and desorption tests was performed on column packed with D141 resin. After one-run treatment with D141 resin, the two-constituent content in the final product was increased from 2.14% and 1.34% in the crude extract of Erigeron multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The preparative separation of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method developed can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials
Gene cloning and characterization of a novel esterase from activated sludge metagenome
A metagenomic library was prepared using pCC2FOS vector containing about 3.0 Gbp of community DNA from the microbial assemblage of activated sludge. Screening of a part of the un-amplified library resulted in the finding of 1 unique lipolytic clone capable of hydrolyzing tributyrin, in which an esterase gene was identified. This esterase/lipase gene consists of 834 bp and encodes a polypeptide (designated EstAS) of 277 amino acid residuals with a molecular mass of 31 kDa. Sequence analysis indicated that it showed 33% and 31% amino acid identity to esterase/lipase from Gemmata obscuriglobus UQM 2246 (ZP_02733109) and Yarrowia lipolytica CLIB122 (XP_504639), respectively; and several conserved regions were identified, including the putative active site, HSMGG, a catalytic triad (Ser92, His125 and Asp216) and a LHYFRG conserved motif. The EstAS was overexpressed, purified and shown to hydrolyse p-nitrophenyl (NP) esters of fatty acids with short chain lengths (≤ C8). This EstAS had optimal temperature and pH at 35°C and 9.0, respectively, by hydrolysis of p-NP hexanoate. It also exhibited the same level of stability over wide temperature and pH ranges and in the presence of metal ions or detergents. The high level of stability of esterase EstAS with its unique substrate specificities make itself highly useful for biotechnological applications
Interference of surface plasmon polaritions controlled by the phase of incident light
Interference patterns of surface plasmon polaritons(SPPs) are observed in the
extraordinary optical transmission through subwavelength holes in optically
thick metal plate. It is found that the phase of incident light can be
transferred to SPPs. We can control the destructive and constructive
interference of SPPs by modulating the relative phase between two incident
beams. Using a slightly displaced Mach-Zehnder interferometer, we also observe
a SPPs interference pattern composed of bright and dark stripes.Comment: 3pages,5figure
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