目的探讨裙带菜多糖(polysaccharides from the Undaria Pinnatifida,PUP)对胃癌细胞的增殖抑制作用及其机制。方法 MTT法分析裙带菜多糖(25、50、100μg/ml)分别作用24、48、72h后,对BGC-823细胞增殖的抑制作用;用透射电子显微镜观察...目的探讨裙带菜多糖(polysaccharides from the Undaria Pinnatifida,PUP)对胃癌细胞的增殖抑制作用及其机制。方法 MTT法分析裙带菜多糖(25、50、100μg/ml)分别作用24、48、72h后,对BGC-823细胞增殖的抑制作用;用透射电子显微镜观察不同浓度(25、50、100μg/ml)裙带菜多糖作用24h、48h、72h后凋亡细胞的结构变化;不同浓度裙带菜多糖(25、50、100μg/ml)作用48h后,用流式细胞术分析BGC-823细胞的凋亡率,RT-PCR法检测survivin基因的表达水平。结果不同浓度的裙带菜多糖均可明显抑制胃癌细胞的增殖(P均<0.05),作用24h后的IC50为38.13μg/ml。不同浓度裙带菜多糖作用48h后,均可诱导BGC-823细胞凋亡,100μg/ml的裙带菜多糖可诱导BGC-823细胞凋亡,凋亡率达69.91%,导致BGC-823细胞发生凋亡特征性超微结构改变,并使BGC-823细胞survivin mRNA表达水平明显降低(P<0.01)。结论裙带菜多糖可抑制BGC-823细胞增殖,诱导肿瘤细胞凋亡,该作用与下调细胞survivin基因表达有关。展开更多
A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patt...A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patterns showed that single phase LaMn0.8Fe0.2O3 with good crystallinity was syn‐thesized at 450℃ after 4 h. Transmission electron microscope images exhibited that the LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h possessed a porous spherical morphology com‐posed of aggregated nanocrystallites. Field emission scanning electron microscope images indicated that the growth of the porous LaMn0.8Fe0.2O3 microspheres has two stages. SEM pictures showed that a higher calcination temperature than 450？？ had an adverse effect on the formation of a po‐rous spherical structure. The LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h displayed a high BET surface area of 55.73 m2/g with a pore size of 9.38 nm. Fourier transform infrared spectra suggested that Sr2＋ions entered the A sites and induced a decrease of the binding energy between Mn and O. The CO conversion with the La1‐xSrxMn0.8Fe0.2O3 （0≤x≤0.6） samples indicated that the La0.4Sr0.6Mn0.8Fe0.2O3 sample had the best catalytic activity and stability. Further analysis by X‐ray photoelectron spectroscopy demonstrated that Sr2＋doping altered the content of Mn4＋ions, oxygen vacancies and adsorbed oxygen species on the surface, which affected the catalytic performance for CO oxidation.展开更多
文摘目的探讨裙带菜多糖(polysaccharides from the Undaria Pinnatifida,PUP)对胃癌细胞的增殖抑制作用及其机制。方法 MTT法分析裙带菜多糖(25、50、100μg/ml)分别作用24、48、72h后,对BGC-823细胞增殖的抑制作用;用透射电子显微镜观察不同浓度(25、50、100μg/ml)裙带菜多糖作用24h、48h、72h后凋亡细胞的结构变化;不同浓度裙带菜多糖(25、50、100μg/ml)作用48h后,用流式细胞术分析BGC-823细胞的凋亡率,RT-PCR法检测survivin基因的表达水平。结果不同浓度的裙带菜多糖均可明显抑制胃癌细胞的增殖(P均<0.05),作用24h后的IC50为38.13μg/ml。不同浓度裙带菜多糖作用48h后,均可诱导BGC-823细胞凋亡,100μg/ml的裙带菜多糖可诱导BGC-823细胞凋亡,凋亡率达69.91%,导致BGC-823细胞发生凋亡特征性超微结构改变,并使BGC-823细胞survivin mRNA表达水平明显降低(P<0.01)。结论裙带菜多糖可抑制BGC-823细胞增殖,诱导肿瘤细胞凋亡,该作用与下调细胞survivin基因表达有关。
基金supported by the National Science Foundation for Young Scientists of China (51202171)~~
文摘A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patterns showed that single phase LaMn0.8Fe0.2O3 with good crystallinity was syn‐thesized at 450℃ after 4 h. Transmission electron microscope images exhibited that the LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h possessed a porous spherical morphology com‐posed of aggregated nanocrystallites. Field emission scanning electron microscope images indicated that the growth of the porous LaMn0.8Fe0.2O3 microspheres has two stages. SEM pictures showed that a higher calcination temperature than 450？？ had an adverse effect on the formation of a po‐rous spherical structure. The LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h displayed a high BET surface area of 55.73 m2/g with a pore size of 9.38 nm. Fourier transform infrared spectra suggested that Sr2＋ions entered the A sites and induced a decrease of the binding energy between Mn and O. The CO conversion with the La1‐xSrxMn0.8Fe0.2O3 （0≤x≤0.6） samples indicated that the La0.4Sr0.6Mn0.8Fe0.2O3 sample had the best catalytic activity and stability. Further analysis by X‐ray photoelectron spectroscopy demonstrated that Sr2＋doping altered the content of Mn4＋ions, oxygen vacancies and adsorbed oxygen species on the surface, which affected the catalytic performance for CO oxidation.
