ERK activation by Ca2+ ionophores depends on Ca2+ entry in lymphocytes but not in platelets, and does not conduct membrane scrambling

Rapid Ca²⁺-dependent phospholipid (PL) reorganization (scrambling) at the plasma membrane is a mechanism common to hematopoietic cells exposing procoagulant phosphatidylserine (PS). The aim of this research was to determine whether activation of the extracellular signal-regulated kinase (ERK) pathway was required for PL scrambling, based on a single report analyzing both responses induced by Ca²⁺ ionophores in megakaryoblastic HEL cells. Ca²⁺ ionophore-stimulated ERK phosphorylation was induced in platelets without external Ca²⁺, whereas exogenous Ca²⁺ entry was crucial for ERK activation in Jurkat T cells. In both cells, membrane scrambling only occurred following Ca²⁺ entry and was not blocked by inhibiting ERK phosphorylation. Furthermore, ERK proteins are strongly phosphorylated in transformed B lymphoblastic cell lines, which do not expose PS in their resting state. Overall, the data demonstrated that ERK activation and membrane scrambling are independent mechanisms. A. Arachiche, I. Badirou: These authors contributed equally to this work. Received 18 June 2008; received after revision 24 September 2008; accepted 1 October 2008     

Radiolarians from the British North‐Polar Expedition (1875–1876): re‐examination of the H. B. Brady (1878) collection

The earliest report on radiolarians from the Arctic Ocean (north of the Arctic Circle) was provided by H. B. Brady (1878 Brady, H. B. 1878. On the reticularian and radiolarian Rhizopoda (Foraminifera and Polycystina) of the North‐Polar Expedition of 1875–76.. Annals and Magazine of Natural History, Series 5, 1: 425–440. [Taylor & Francis Online] , [Google Scholar]). He documented the occurrences of 10 genera from soundings in northern Baffin Bay and north of Greenland, but he did not illustrate any specimens in his report. We have re‐examined Brady's original slide collection, housed at the Natural History Museum, London (NHM), in order to refine his radiolarian identifications to species level. We have identified 11 radiolarian taxa in his slides, but some are definitely more characteristic of tropical oceans rather than high northern latitudes. We conclude that this is most likely due to sample contamination or misidentification of samples. Therefore, the actual occurrence of tropically affiliated radiolarians recorded from the Arctic is uncertain and should be regarded with suspicion.     

基于HJ-1B卫星的作物秸秆提取及其焚烧火点判定模式

作物秸秆焚烧产生的气体和颗粒物严重污染大气环境,威胁人类健康,给交通带安全带来隐患,利用遥感技术优势监管秸秆焚烧火点具有重要的现实意义.文中基于HJ-1B卫星CCD多光谱遥感数据和IRS热红外遥感数据,以中国江苏中东部为研究区,开展作物秸秆提取及其焚烧火点判定的一体化研究.根据秸秆的光谱特征研究建立了秸秆乘积指数(SMI),结合其纹理信息可从HJ-1BCCD遥感图像上快速有效的提取出秸秆分布,继之结合修正后的火点探测算法可对HJ-1BIRS遥感数据进行火点提取.在秸秆分布和火点探测结果矢量化的基础上,通过GIS技术进行火点叠置分析,可有效地判定作物秸秆火点分布,同时结合实地调研及与MODIS火点产品比对分析验证评价了本研究方法的可行性和有效性.     

结核分支杆菌Ag85B DNA疫苗构建、免疫原性及其保护效力

构建结核分支杆菌分泌蛋白Ag85B编码基因的DNA疫苗,研究其免疫原性和保护效力.构建该DNA疫苗并经鉴定后,应用Qiagen试剂盒大量纯化无内毒素的质粒DNA.将C57BL/6小鼠随机分为4组,分别3周间隔3次用生理盐水（A）、载体质粒（B）、卡介苗（C）、Ag85B DNA疫苗（D）免疫小鼠,通过ELISA方法检测血清中抗Ag85B抗体及其亚型.第三次免疫后28 d用结核分支杆菌H37Rv攻击,观察小鼠体重变化,攻击4周后检测细胞因子IFN-γ、IL-12,进行肺组织病理检查及菌落计数等.经Ag85B DNA疫苗免疫的小鼠特异性抗体IgG均显著高于对照组,而且IgG2b均高于IgG1和IgG2a.结核分支杆菌攻击后各组小鼠体重变化呈现不同趋势,A、B组小鼠体重从第3周开始下降;C组体重总体呈上升趋势;D组体重第2周开始下降,之后维持不变.MTT法检测脾淋巴细胞增殖实验中D组的刺激指数显著高于其它组;D组小鼠脾淋巴细胞转化率也显著高于A、B组.肺组织菌落计数C组最低,其次是D组.大体病理结果显示C组和D组肺组织病变较A、B组轻.A、B组肺泡腔内有较多渗出液,肺泡壁充血、水肿.C组肉芽肿数目最多.上述结果表明Ag85B DNA疫苗具有较强的免疫原性,呈TH1型细胞介导的免疫应答.Ag85B DNA疫苗的免疫保护效力不如BCG,有待进一步研究其应用价值.     

胞嘧啶脱氨基酶APOBEC1研究进展

为全面理解载脂蛋白B mRNA(ApoB mRNA)编辑酶催化多肽-1(APOBEC1)的作用机制,介绍了APOBEC1和ApoB mRNA的蛋白及核酸序列,总结并绘制了APOBEC1与不同的辅助蛋白的结合模型,阐述了APOBEC1催化ApoB mRNA第6 666位的胞嘧啶(C_(6666))脱氨基化分子机制.列举了啮齿动物APOBEC1抑制多种逆转录病毒的研究报道,介绍了兔源APOBEC1结合人类免疫缺陷病毒1(HIV-1)的病毒粒子并编辑病毒基因组的机理.同时介绍了APOBEC1通过编辑胞嘧啶或与AU富集元件(ARE)结合来调控癌症等疾病相关的细胞因子表达.     

基态HCO分子的结构与势能函数

采用B3LYP密度泛函方法计算优化出HCO分子基态的结构参数,离解能和力常数。用多体项展式理论导出基态HCO分子(2A’)的解析势能函数,其势能面正确地复现出HCO分子的平衡结构特征。     

Photocatalytic degradation kinetics of Rhodamine B catalyzed by nanosized TiO<Subscript>2</Subscript> film

A fixed bed photocatalytic reactor was designed,and dynamic fast scan of UV-Vis adsorption spectrum was adopted to study the photocatalytic degradation dynamic behavior of Rhodamine B,a kind of dye generally recognized as to be degraded difficultly ,on the surface of nanosized TiO2 thin film,The results indicate that the photocatalytic degradation process of Rhodamine B does not comply with the first-order reaction kinetic process ,As a result,a kinetic model of Rhodamine B photocataly tic degradation ,reaction is brough forward ,and the model is proved by the theoretical deduction and experiment.     

并行数据库系统PAROⅡ连接算法

提出了并行数据库系统的哈希轮转（Hash-Round-Robin）数据划分方法以及其于该划分方法的并行记录分布B^n树，给出了基于该树的并行连接算法，分析了该算法的效率，这种连接算法充分利用了数据的已有分布及B^n树的特性，还利用了哈希轮转划分的特性，提高了并行连接的效率，该算法已经在自主研制的并行数据库管理系统PAROⅡ中得到实现。     

苝二酰亚胺敏化TiO_2可见光光催化降解罗丹明B

采用水热法制备了苝二酰亚胺(PTCDI)敏化的光催化剂TiO2/PTCDI以及PTCDI和酞菁铜(CuPc)共敏化的可见光光催化剂(TiO2/PTCDI)-CuPc。利用XRD,TEM和UV-Vis光谱对催化剂进行表面形貌和结构表征。以罗丹明B的光催化降解为模型反应,考察敏化样品的可见光光催化性能。研究表明染料共敏化样品(TiO2/PTCDI)-CuPc的活性比TiO2和TiO2/PTCDI分别提高了223%和113%。应用能带结构理论,阐明了TiO2/PTCDI和(TiO2/PTCDI)-CuPc的光生电子转移路径和光催化降解机理。