Crisis-Like Behavior in China's Stock Market and Its Interpretation

In order for China to play a bigger, more positive role in the world, it is important for China to have a healthy capital market. This perception motivates us to examine the health of China''s capital market, especially the severity of the overall loss of the listed companies in China and the effects of accounting irregularities on the losses. We show the overall loss of the listed companies was very severe, in particular, crisis-like behavior emerged in the fourth quarter of 2002, 2004, 2005, and 2008. We further observe that loss in the fourth quarter was much greater than the average loss of the first three quarters in the same year. The most straightforward interpretation of this loss pattern is that companies underreported losses in the first three quarters, to boost their stock values in most time of the year. However, in the fourth quarter, accounting balance of the whole year dictated that the reported loss in the fourth quarter had to be much greater than the actual loss. Fortunately, such irregularity has been greatly reduced, thanks to the accounting reforms in China in 2007.     

转酮酶在癌症中的作用及其机制研究进展

肿瘤细胞的一大重要特征是代谢水平的改变。戊糖磷酸途径作为细胞产生NADPH和五碳糖的主要通路,在肿瘤发生发展过程中发挥着重要功能。转酮酶是戊糖磷酸途径中的关键酶之一,越来越多的研究表明其与癌症病人预后具有显著相关性。作为肿瘤诊断、治疗的潜在靶标,转酮酶具有重要的研究价值。我们就目前癌症研究中对转酮酶的研究进展做简要综述。     

骨骼肌和心肌缺血后处理对兔缺血/再灌注心肌的保护作用

目的:观察骨骼肌缺血后处理(RPostC)、心肌的缺血后处理(MPostC)对缺血/再灌注心肌保护作用是否存在差异以及两者联合后作用是否叠加。方法:健康新西兰大白兔3O只,随机分为5组(n=6):缺血对照组(Con)、假手术组(sham)、心肌缺血后处理组(MPostC)和肢体缺血后处理组(RPostC)及心肌缺血后处理联合肢体缺血后处理组(MPostC+RPostC)。采用开胸结扎冠状动脉左室支45 min,再灌注120min方法制作缺血/再灌注模型,采用短暂结扎双侧髂外动脉固定部位5 min造成骨骼肌短暂缺血。以Evans蓝标记心肌缺血区范围,以TTC法检测梗死心肌范围,并分别于缺血前、后及再灌注1、2 h测定血浆磷酸肌酸激酶(CPK)活性和乳酸脱氢酶(LDH)含量。结果:和Con组相比,MPostC和RPostC组心肌梗死范围均明显降低(P<0.05);MPostC联合RPostC组心肌梗死范围与MPostC或RPostC组相比,均进一步降低(均P<0.05)。但MPostC组及RPostC组之间心肌坏死范围未见统计学差异。再灌注120 min末血浆CPK活性及LDH含量也显示相似趋势。结论:骨骼肌缺血后处理及心肌后处理对缺血/再灌注心肌均具有明显保护作用;且两者作用可以叠加;但骨骼肌和心肌后处理之间保护作用未显示统计学差异。     

Involvement of SSAO-mediated deamination in adipose glucose transport and weight gain in obese diabetic KKAy mice

Semicarbazide-sensitive amine oxidase (SSAO) is located on outer surfaces of adipocytes and endothelial and vascular smooth muscle cells. This enzyme catalyzes deamination of methylamine and aminoacetone, leading to production of toxic formaldehyde and methylglyoxal, respectively, as well as hydrogen peroxide and ammonium. Several lines of evidence suggest that increased SSAO activity is related to chronic inflammation and vascular disorders related to diabetic complications. We found that a highly potent and selective SSAO inhibitor, (E)-2-(4-fluorophenethyl)-3-fluoroallylamine (FPFA), was capable of reducing numbers of atherosclerotic lesions as well as weight gain in obese KKAy mice fed an atherogenic diet. SSAO inhibitors cause a moderate and long-lasting hyperglycemia. Such an increase in serum glucose is a result of reduction of glucose uptake by adipocytes. SSAO-mediated deamination of endogenous methylamine substrates induces adipocyte glucose uptake and lipogenesis. Highly selective SSAO inhibitors can effectively block induced glucose uptake. The results suggest that increased SSAO-mediated deamination may be concomitantly related to obesity and vascular disorders associated with type 2 diabetes.     

8—MOP对体外培养人癌细胞的光敏灭活作用

本文根据MTT只能被活的增殖细胞中线粒体切断形成紫色甲(?)的原理,测定了8—甲氧基补骨脂素(8—MOP)对体外培养人癌细胞系HCT、KB和BEL细胞的光敏灭活作用。结果表明,8—MOP和UVA光照对这几种人癌细胞有肯定的灭活作用,该作用与8—MOP剂量和光照时间以及细胞种类有关;MTT法可以作为光敏剂活性检测的一种快捷方法。     

Optimization of sulfated modification conditions of tremella polysaccharide and effects of modifiers on cellular infectivity of NDV

Based on our previous research, sulfated modification conditions of Tremella polysaccharide (TPS), the chlorosulfonic acid to pyridine (CSA-Pry) ratio, reaction temperature and time, were optimized by L₉ (3⁴) orthogonal design taking the yield and degree of sulfation (DS) of modifiers as indexes. Two TPSs, TPS_tp and TPS_70c, were modified under optimized conditions. The effects of two modifiers, sTPS_tp and sTPS_70c, on cellular infectivity of NDV were determined by MTT method taking the non-modified TPS_tp, TPS_tc and TPS_70c as controls. The results showed that the optimized modification conditions were reaction temperature of 80 °C, CSA-Pry ratio of 1:6 and reaction time of 1.5 h. Five polysaccharides at proper concentrations could significantly inhibit the infectivity of NDV to CEF. The virus inhibitory rates of sTPS_tp at 1.563 μg mL⁻¹ group were the highest and significantly higher than those of other three non-modified polysaccharide groups in three sample-adding modes. This indicated that sulfated modification could significantly improve the antiviral activity of TPS. sTPS_tp possessed the best efficacy and would be as a component of antiviral polysaccharide drug.     

小麦TaMlo基因的原核表达、抗体制备及细胞化学分析(简报)

白粉病菌(Blumeria graminis)是一类高度专化性的寄生真菌,可侵染650多种单子叶植物和 9000多种双子叶植物,能够引起多种麦类作物的白粉病,给农业生产带来巨大的损失。由于白粉病菌生理小种多、变异快,所以利用专化性抗病基因难以解决植物的持久抗病性问题。人们在研究大麦白粉病时．发现大麦Mlo基因的隐性突变可导致大麦对绝大多数白粉病菌生理小种的高效持久的广谱抗病性。Schulze-Lefert等多家实验室合作于1997年成功克隆了野生的 Mlo基因。进一步研究表明．该基因编码一种植物特有的具有7个跨膜区和羧基端长尾的膜蛋白(Mlo),它可能对植物细胞的坏死起负调控作用。但Mlo基因如何表达及其在白粉病菌发育中的作用机制尚不清楚。     

Nuclear retention of the lncRNA SNHG1 by doxorubicin attenuates hnRNPC–p53 protein interactions

The protein p53 plays a crucial role in the regulation of cellular responses to diverse stresses. Thus, a major priority in cell biology is to define the mechanisms that regulate p53 activity in response to stresses or maintain it at basal levels under normal conditions. Moreover, further investigation is required to establish whether RNA participates in regulating p53's interaction with other proteins. Here, by conducting systematic experiments, we discovered a p53 interactor—hnRNPC—that directly binds to p53, destabilizes it, and prevents its activation under normal conditions. Upon doxorubicin treatment, the lncRNA SNHG1 is retained in the nucleus through its binding with nucleolin and it competes with p53 for hnRNPC binding, which upregulates p53 levels and promotes p53‐dependent apoptosis by impairing hnRNPC regulation of p53 activity. Our results indicate that a balance between lncRNA SNHG1 and hnRNPC regulates p53 activity and p53‐dependent apoptosis upon doxorubicin treatment, and further indicate that a change in lncRNA subcellular localization under specific circumstances is biologically significant.     

复杂疾病靶基因识别与网络重建的计算系统生物研究

复杂疾病相关靶基因的识别、构建疾病驱使相关基因网络及进行疾病机制研究,是功能基因组学研究中非常重要的科学问题。文章以计算系统生物学的观点和三维的角度,综述了基于生物谱（SNP遗传谱、芯片表达谱和2D-PAGE蛋白质谱等）的复杂疾病靶基因识别、多水平（SNPs虚拟网络、基因调控网络、蛋白质互作网络等）遗传网络逆向重构方法,及不同水平的网络之间在生物学和拓扑学上的纵向映射关系,并给出复杂疾病靶基因识别与网络关系的计算系统生物方法研究的未来展望。