ERK干扰质粒的构建及对胃癌细胞株BGC823 DcR3表达的影响

目的探讨胃癌发展的分子机制,通过构建ERK1/2shRNA真核表达载体,体外研究其对人胃癌细胞株BGC823ERK1/2蛋白及DcR3表达水平的影响。方法应用PRNAT-U6.1/Neo载体构建ERK1/2基因shRNA重组质粒,经脂质体法导入BGC823细胞中,分别设置对照组、干扰组和U0126抑制剂组。Westernblot法检测转染后BGC823细胞及抑制剂使用后ERK1/2蛋白的表达变化,荧光显微镜检测质粒自带GFP基因的表达情况确认转染效率,ELISA法检测各组细胞上清中DcR3分泌蛋白的表达特点。结果成功构建ERK1/2基因shRNA重组质粒。证明了ERK1/2蛋白的表达与DcR3的分泌水平在BGC823细胞株中呈正相关。结论 ERK1/2干扰质粒明显降低BGC823细胞的ERK1/2蛋白表达水平,ERK信号通路对DcR3的分泌具有重要调控作用,为其下游调控机制的研究奠定了基础

肝癌发展中FasL及其受体Fas/DcR3的表达分析

目的研究小鼠肿瘤发生早期肿瘤坏死因子超家族成员FasL及其受体的表达特点,及其与免疫调节相关分子表达的时空关系,探讨其在诱导肿瘤免疫耐受中的作用。方法建立小鼠实体瘤模型,采用RT-PCR方法检测肿瘤组织中可溶型FasL、Fas及DcR3、TGF-β、IL-10在肿瘤发生不同时相的表达,同时,应用ELISA方法定量检测血清中TGF-β、IL-10的表达。结果在早期的肿瘤组织中,Fas的表达先于DcR3,其后DcR3大量表达,而Fas的表达则下调直至丢失,DcR3、FasL同时表达并上调,TGF-β和IL-10也随肿瘤的表达而上调。TGF-β同DcR3的表达具有空间位置的一致性。FasL、DcR3、TGF-β和IL-10的表达水平同肿瘤的生长呈正相关。结论随着肿瘤不断的生长,肿瘤局部的免疫应答逐渐趋向于负调节,FasL、DcR3在诱导肿瘤免疫耐受的过程中可能发挥着重要作用

Determination of Lead Content in Standard Materials of Lake Sediment and Tea by ID-ICP-MS

采用2种微波消解体系(HNO3-H2O2和HNO3-H2O2-HF)及3种定量模式(同位素稀释法、标准工作曲线法和标准加入法),对沉积物和茶叶标准物质中的铅进行测定,结果表明:同位素稀释质谱法的各项检测指标显著优于其它两种定量模式(茶叶中铅含量测定值为4.30μg/g),标准加入法次之(3.75μg/g),标准工作曲线法较差(3.61μg/g)。二种微波消解体系中,加HF酸优于不加HF酸,不加HF,茶叶中铅的回收率仅有89%,加入HF则上升为98%。Three different quantitative modes,namely external calibration,standard addition and isotope diluˉtion were compared for the determination of lead contents in lake sediment and tea standard materials with two digestion systems.The results showed that the isotope dilution gave the highest accuracy and precision in comˉparison with the other two modes.But the results were affected by the digestion system.For example,the reˉcoveries of lead content for tea were98%and89%for HNO 3 -H 2 O 2 -HF and HNO 3 -H 2 O 2 digesting sysˉtem,respectively.福建省重大科技项目子课题(2003Y005-04);; 厦门大学现代分析科学教育部重点实验室开放课题(B40402

Determination of lead contents in tea and vegetable samples by isotope dilution coupled with inductively coupled plasma mass spectrometry

采用同位素稀释电感耦合等离子体质谱(ID-ICP-MS)法测定了铅的含量,通过对茶叶标准物质(GBW-07605)中铅的测定,考察了方法的准确度和精密度,比较了同位素稀释法与普通外标定量法的测定结果。在5mLHNO3～0.5mLHF～1mLH2O2的消解体系中,ID-ICP-MS法测量茶叶中铅的回收率可达97.7%,相对标准偏差(RSD)小于1.2%。实验对市售的12种茶叶和10种蔬菜中Pb进行测定,铅含量符合相应国家标准的样品分别占总样品数的83%和90%。该法适合于植物样品中微量铅的测定。A method of isotope dilution coupled with inductively coupled plasma mass spectrometry (ID-ICP-MS) was applied to determine lead contents in tea and vegetable samples. The accuracy and precision of the method were validated by the measurement of tea standard reference samples, and its results were compared with those of the quantitative mode of external calibration of ICP-MS. The recovery of the ID-ICP-MS mode was 93.9% with RSDs of than 1.2% in the digesting system of 5 mL HNO3～0.5 mL HF～1 mL H_2O_2, which was superior to the external calibration mode. Lead contents in 12 kinds of commercial tea and 10 kinds of vegetable samples were determined by ID-ICP-MS. The results showed that 83% and 90% of the tea and vegetable samples accorded with the limitations for the lead contents in the National Standards of China, respectively. The method of ID-ICP-MS, with the merits of high sensitivity and precision, is suitable for the measurement of lead contents in plants.福建省重大科技项目子课题(2003Y005-04);; 厦门大学现代分析科学教育部重点实验室开放课题(B40402

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies