Cerebral Amyloid Angiopathy (CAA) occurs commonly among the elderly and almost invariably in patients with Alzheimer’s Disease (AD). The β-amyloid peptides (Aβ) are produced via the amy-loidogenic processing of β-...Cerebral Amyloid Angiopathy (CAA) occurs commonly among the elderly and almost invariably in patients with Alzheimer’s Disease (AD). The β-amyloid peptides (Aβ) are produced via the amy-loidogenic processing of β-Amyloid Precursor Protein (APP) by β-secretase-1 (BACE1) and γ- secretase. Vascular endothelial cells are lately shown to possess the molecular machinery of Aβ production, which might participate in the development of CAA. Hypercholesterolemia is considered a risk factor for AD, whereas less is known if cholesterol may modulate endothelial Aβ production. In the present study we verified the amyloidogenic capability of Human Umbilical Vein Endothelial Cells (HUVECs) in vitro and explored the effect of cholesterol exposure on their amy-loidogenic potential. Cholesterol treatments at 12.5 and 25 mg/dL significantly elevated APP, BACE1 and APP β-CTF protein levels and β-site APP cleavage activity in cell lysates, and Aβ40 levels in culture medium. However, coincubation with cholesterol at 50 and 100 mg/dL attenuated the viability of the cultured cells and diminished their amyloidogenic capability. These findings suggest that high cholesterol exposure is stressful to vascular endothelial cells, and at a certain dosage range can promote an amyloidogenic response in these cells.展开更多
Walnut dreg protein hydrolysates(WDPHs)exhibit a variety of biological activities,however,the cyclooxygenase-2(COX-2)inhibitory peptide of WDPHs remain unclear.The aim of this study was to rapidly screen for such pept...Walnut dreg protein hydrolysates(WDPHs)exhibit a variety of biological activities,however,the cyclooxygenase-2(COX-2)inhibitory peptide of WDPHs remain unclear.The aim of this study was to rapidly screen for such peptides in WDPHs through a combination of in silico and in vitro analysis.In total,1262 peptide sequences were observed by nano liquid chromatography/tandem mass spectrometry(nano LC-MS/MS)and 4 novel COX-2 inhibitory peptides(AGFP,FPGA,LFPD,and VGFP)were identified.Enzyme kinetic data indicated that AGFP,FPGA,and LFPD displayed mixed-type COX-2 inhibition,whereas VGFP was a non-competitive inhibitor.This is mainly because the peptides form hydrogen bonds and hydrophobic interactions with residues in the COX-2 active site.These results demonstrate that computer analysis combined with in vitro evaluation allows for rapid screening of COX-2 inhibitory peptides in walnut protein dregs.展开更多
Phlorizin(PHL)is a natural compound with strong antioxidant properties mainly found in apples.In this paper,the interaction mechanism of PHL with pepsin and trypsin was comparatively evaluated by computer simulation,f...Phlorizin(PHL)is a natural compound with strong antioxidant properties mainly found in apples.In this paper,the interaction mechanism of PHL with pepsin and trypsin was comparatively evaluated by computer simulation,fluorescence spectra,circular dichroism(CD),and Fourier transform infrared(FT-IR)spectra at a molecular level.Fluorescence spectra showed that PHL quenches the pepsin/trypsin by static quenching.Thermodynamic parameters indicated that PHL binds to pepsin mainly through hydrogen bonds and van der Waals forces,and that of trypsin was electrostatic forces.The ground state complexes PHL and protease have a moderate affinity of 105 L/mol PHL binds more strongly to trypsin than to pepsin.CD and FT-IR spectra results showed that pepsin/trypsin decreased theβ-sheet content and slightly changed its secondary structure upon PHL.These experimental results are mutually verified with the predicted computer-aid simulation results.Upon PHL and trypsin binding,the antioxidant capacity of PHL was elevated.Nevertheless,the antioxidant capacity of PHL was decreased after binding to pepsin.This work elucidates the binding of PHL binding mechanisms to pepsin/trypsin and provides useful information for the digestion of PHL to improve the application of PHL in food processing.展开更多
Research on human behavior has attracted increasing attention recently because of its scientific significance and potential applications.Some empirical results have indicated that the timing of many human activities f...Research on human behavior has attracted increasing attention recently because of its scientific significance and potential applications.Some empirical results have indicated that the timing of many human activities follows non-Poisson statistics.We analyze a real-life huge dataset of short message communication with 6326713 users and 37577781 records during the 2006 Chinese New Year.The results show that the number of short message sendings,the interevent time between two consecutive short message sendings and the response time all follow heavy-tailed distribution.We further observe a strongly positive correlation between the activity and the power-law exponent of the interevent time distribution.In addition,the short message communication system displays a bursty property yet no memory effects,which is in particular different from some well-studied human-activited systems such as email-sending,library-loaning and file printing.展开更多
文摘Cerebral Amyloid Angiopathy (CAA) occurs commonly among the elderly and almost invariably in patients with Alzheimer’s Disease (AD). The β-amyloid peptides (Aβ) are produced via the amy-loidogenic processing of β-Amyloid Precursor Protein (APP) by β-secretase-1 (BACE1) and γ- secretase. Vascular endothelial cells are lately shown to possess the molecular machinery of Aβ production, which might participate in the development of CAA. Hypercholesterolemia is considered a risk factor for AD, whereas less is known if cholesterol may modulate endothelial Aβ production. In the present study we verified the amyloidogenic capability of Human Umbilical Vein Endothelial Cells (HUVECs) in vitro and explored the effect of cholesterol exposure on their amy-loidogenic potential. Cholesterol treatments at 12.5 and 25 mg/dL significantly elevated APP, BACE1 and APP β-CTF protein levels and β-site APP cleavage activity in cell lysates, and Aβ40 levels in culture medium. However, coincubation with cholesterol at 50 and 100 mg/dL attenuated the viability of the cultured cells and diminished their amyloidogenic capability. These findings suggest that high cholesterol exposure is stressful to vascular endothelial cells, and at a certain dosage range can promote an amyloidogenic response in these cells.
文摘本文以76份青稞为研究对象,利用近红外光谱仪采集青稞4000~10000 cm-1波段光谱,并联合其水分、β-葡聚糖、直链淀粉、蛋白质实测含量数值,构建了基于近红外光谱技术的青稞特征营养成分含量快速检测模型。结果显示,SG卷积平滑(Savitzky Golay,SG)是水分、直链淀粉、β-葡聚糖含量的偏最小二乘法(Partial Least Squares,PLS)预测模型的最优光谱预处理方法,而SG卷积平滑+多元散射校正(Multiplicative Scatter Correction,MSC)是蛋白质含量的偏最小二乘法(PLS)预测模型的最优光谱预处理方法。为进一步提高青稞各成分含量预测模型的准确性,考察了竞争性自适应重加权法(Competitive Adaptive Reweighted Sampling,CARS)、连续投影算法(Successive Projections Algorithm,SPA)和变量组合集群分析混合迭代保留信息变量法(Variables Combination Population Analysis and Iterative Retained Information Variable,VCPA-IRIV)特征波长选择算法对模型预测结果的影响。结果表明,VCPA-IRIV处理可有效提高水分、直链淀粉、蛋白质含量预测模型的预测决定系数,降低预测均方根误差;CARS对β-葡聚糖含量预测模型优化效果显著。基于上述最优方法建立的青稞水分、β-葡聚糖、直链淀粉、蛋白质实测含量预测模型,其预测相关系数分别为0.9868、0.9808、0.9701、0.9879;预测均方根误差分别为0.2042、0.1846、0.8135、0.2095。综上,本研究建立的基于近红外光谱的青稞特征营养成分含量快速检测模型具有较高的准确性,对加工企业快速了解原料品质及高效筛选合格原料有一定指导意义。
基金supported by the Major Project of Science and Technology Department of Yunnan Province (202002AA100005 and 202102AE090027-2)the Project of Yunnan Province Food and Drug Homologous Resources Functional Food Innovation Team (A3032023057)+2 种基金the YEFICRC project of Yunnan provincial key programs (2019ZG009)Yunnan Province Ten Thousand Plan Industrial Technology Talents project (YNWR-CYJS-2020-010)the Yunnan Provincial Department of Science and Technology Agricultural Joint Special Project (202101BD070001-120)。
文摘Walnut dreg protein hydrolysates(WDPHs)exhibit a variety of biological activities,however,the cyclooxygenase-2(COX-2)inhibitory peptide of WDPHs remain unclear.The aim of this study was to rapidly screen for such peptides in WDPHs through a combination of in silico and in vitro analysis.In total,1262 peptide sequences were observed by nano liquid chromatography/tandem mass spectrometry(nano LC-MS/MS)and 4 novel COX-2 inhibitory peptides(AGFP,FPGA,LFPD,and VGFP)were identified.Enzyme kinetic data indicated that AGFP,FPGA,and LFPD displayed mixed-type COX-2 inhibition,whereas VGFP was a non-competitive inhibitor.This is mainly because the peptides form hydrogen bonds and hydrophobic interactions with residues in the COX-2 active site.These results demonstrate that computer analysis combined with in vitro evaluation allows for rapid screening of COX-2 inhibitory peptides in walnut protein dregs.
基金supported by the National Natural Science Foundation of China(21808020)the Applied Basic Research Program of Science&Technology Department of Sichuan Province(2018JY0151)。
文摘Phlorizin(PHL)is a natural compound with strong antioxidant properties mainly found in apples.In this paper,the interaction mechanism of PHL with pepsin and trypsin was comparatively evaluated by computer simulation,fluorescence spectra,circular dichroism(CD),and Fourier transform infrared(FT-IR)spectra at a molecular level.Fluorescence spectra showed that PHL quenches the pepsin/trypsin by static quenching.Thermodynamic parameters indicated that PHL binds to pepsin mainly through hydrogen bonds and van der Waals forces,and that of trypsin was electrostatic forces.The ground state complexes PHL and protease have a moderate affinity of 105 L/mol PHL binds more strongly to trypsin than to pepsin.CD and FT-IR spectra results showed that pepsin/trypsin decreased theβ-sheet content and slightly changed its secondary structure upon PHL.These experimental results are mutually verified with the predicted computer-aid simulation results.Upon PHL and trypsin binding,the antioxidant capacity of PHL was elevated.Nevertheless,the antioxidant capacity of PHL was decreased after binding to pepsin.This work elucidates the binding of PHL binding mechanisms to pepsin/trypsin and provides useful information for the digestion of PHL to improve the application of PHL in food processing.
基金by the National Natural Science Foundation of China under Grant Nos 90924011,60973069,10975126,70971089 and 70871082the China Postdoctoral Science Foundation under Grant No 201003694the Sichuan Provincial Science and Technology Department under Grant No 2010HH0002.
文摘Research on human behavior has attracted increasing attention recently because of its scientific significance and potential applications.Some empirical results have indicated that the timing of many human activities follows non-Poisson statistics.We analyze a real-life huge dataset of short message communication with 6326713 users and 37577781 records during the 2006 Chinese New Year.The results show that the number of short message sendings,the interevent time between two consecutive short message sendings and the response time all follow heavy-tailed distribution.We further observe a strongly positive correlation between the activity and the power-law exponent of the interevent time distribution.In addition,the short message communication system displays a bursty property yet no memory effects,which is in particular different from some well-studied human-activited systems such as email-sending,library-loaning and file printing.
