Numerical simulation of two-phase non-Newtonian blood flow with fluid-structure interaction in aortic dissection

The behavior of blood cells and vessel compliance significantly influence hemodynamic parameters, which are closely related to the development of aortic dissection. Here the two-phase non-Newtonian model and the fluid-structure interaction (FSI) method are coupled to simulate blood flow in a patient-specific dissected aorta. Moreover, three-element Windkessel model is applied to reproduce physiological pressure waves. Important hemodynamic indicators, such as the spatial distribution of red blood cells (RBCs) and vessel wall displacement, which greatly influence the hemodynamic characteristics are analyzed. Results show that the proximal false lumen near the entry tear appears to be a vortex zone with a relatively lower volume fraction of RBCs, a low time-averaged wall shear stress (TAWSS) and a high oscillatory shear index (OSI), providing a suitable physical environment for the formation of atherosclerosis. The highest TAWSS is located in the narrow area of the distal true lumen which might cause further dilation. TAWSS distributions in the FSI model and the rigid wall model show similar trend, while there is a significant difference for the OSI distributions. We suggest that an integrated model is essential to simulate blood flow in a more realistic physiological environment with the ultimate aim of guiding clinical treatment.     

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。     

Targeting Hedgehog signaling pathway and autophagy overcomes drug resistance of BCR-ABL-positive chronic myeloid leukemia

The frontline tyrosine kinase inhibitor (TKI) imatinib has revolutionized the treatment of patients with chronic myeloid leukemia (CML). However, drug resistance is the major clinical challenge in the treatment of CML. The Hedgehog (Hh) signaling pathway and autophagy are both related to tumorigenesis, cancer therapy, and drug resistance. This study was conducted to explore whether the Hh pathway could regulate autophagy in CML cells and whether simultaneously regulating the Hh pathway and autophagy could induce cell death of drug-sensitive or -resistant BCR-ABL⁺ CML cells. Our results indicated that pharmacological or genetic inhibition of Hh pathway could markedly induce autophagy in BCR-ABL⁺ CML cells. Autophagic inhibitors or ATG5 and ATG7 silencing could significantly enhance CML cell death induced by Hh pathway suppression. Based on the above findings, our study demonstrated that simultaneously inhibiting the Hh pathway and autophagy could markedly reduce cell viability and induce apoptosis of imatinib-sensitive or -resistant BCR-ABL⁺ cells. Moreover, this combination had little cytotoxicity in human peripheral blood mononuclear cells (PBMCs). Furthermore, this combined strategy was related to PARP cleavage, CASP3 and CASP9 cleavage, and inhibition of the BCR-ABL oncoprotein. In conclusion, this study indicated that simultaneously inhibiting the Hh pathway and autophagy could potently kill imatinib-sensitive or -resistant BCR-ABL⁺ cells, providing a novel concept that simultaneously inhibiting the Hh pathway and autophagy might be a potent new strategy to overcome CML drug resistance.     

不同地区麦冬遗传多样性的ISSR分析

利用ISSR分子标记技术对5个地区6个麦冬居群进行遗传多样性分析。选用10条扩增带型清晰且重复性好的引物进行扩增,共获得115条带,其中89条具有多态性,多态性比例为77.39%。当遗传相似系数(GS)为0.61时,可将6个麦冬居群分为2大类群。居群的GS平均值为0.643,表明供试居群之间存在较近的亲缘关系,且地域越近的其亲缘关系关系越近。研究表明ISSR分子标记技术能够很好地用于不同地域同种物种的亲缘关系分析。     

Large-scale production of foreign proteins via the novel plant transient expression system in <Emphasis Type="Italic">Pisum sativum</Emphasis> L.

Transient expression of foreign genes by Agrobacterium infiltration is a versatile technique that can be used as a rapid tool for functional protein production in plants. A reproducible protocol of large-scale production of foreign proteins via the novel plant transient expression system in Pisum sativum L. was established in our study. Non-detached plants from soil-independent culture were used as the target organ, and vacuum infiltrating mediated by Agrobacterium tumefaciens harboring green fluorescent protein (GFP) gene was performed. Step-by-step optimization was performed and showed that the quality of plant material as well as agro-infiltration conditions were the major factors influencing the gene expression. Monitoring the transient GFP expression daily, the highest expression level was achieved on the 8th day post-infiltration. Evidence of anti-acidic fibroblast growth factor-single chain variable fragment (anti-aFGF-scFv) gene expression in pea seedling was also achieved using agro-mediated vacuum infiltration system. Our work proves that the system is suitable for the largescale production of pharmaceutical proteins. The in planta infiltration system described here provides a powerful tool to explore easily gene expression in Pisum sativum L. avoiding tissue culture steps and the labor-intensive generation of transgenic plants.     

菜籽饼肥对香蕉枯萎病的防效及其对土壤细菌的影响

研究菜籽饼肥对香蕉枯萎病的防治效果,探究菜籽饼肥施用后对土壤细菌群落的影响.设置2组实验,CN组为菜籽饼肥处理组,YN组为对照实验组.种植120d后,统计各组的发病率;利用qPCR技术检测2组中的FOC4孢子数量;采集2组土壤,利用Illumina Miseq高通量测序平台对CN处理组与YN对照组的土壤细菌群落结构和差异进行分析对比.实验研究发现:(1)施菜籽饼肥的CN处理组枯萎病发病率比YN对照组低63.33％;施用菜籽饼肥的处理土壤中FOC4的数量由2.94×104个/克土下降为1.96×103个/克土,YN对照组土壤中FOC4孢子的数量由2.94×104个/克土上升为4.55×105个/克土,CN处理组较YN对照组枯萎病菌数量下降了 2个数量级;(2)土壤细菌宏基因组微生物分类测序结果显示,CN处理组的Alpha多样性指数均优于YN对照组,这表明施用菜籽饼肥后增加了土壤细菌群落的丰度及多样性;(3)在门水平上,菜籽饼肥处理增加了变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)的相对丰度,同时也降低了酸杆菌门(Acidobact-eria)、厚壁菌门(Firmicutes)和Patescibacteria等菌门的相对丰度;在属水平,CN处理组中的不动杆菌属(Aci-netobacter)、水杆菌属(Aquabacterium)、热单胞菌属(Thermomonas)、产黄杆菌属(Rhodanobacter)、假单胞菌属(Pseudomonas)和奥托氏菌属(Ottowia)等菌属的相对丰度较YN对照组有明显提高,而酸热菌属(Acidother-mus)、Bryobacter菌属以及Acidipila等菌属相对丰度较YN对照组有所减少.施用菜籽饼肥可以改变土壤中细菌的群落结构,显著降低土壤中FOC4孢子数量,从而降低香蕉枯萎病的发病率.本研究结果为菜籽饼肥用于香蕉枯萎病综合防控提供了理论依据.     

"In vitro" protection of DNA from Fenton reaction by plant polyphenol verbascoside

The protection effect of verbascoside (Ver) against Fenton reaction on plasmid pBR322 DNA was studied using agarose gel electrophoresis and UV-visible spectroscopy. The pBR322 plasmid DNA is damaged by hydroxyl radical (OH*) generated from the Fenton reaction with H2O2 and Fe(II) or Fe(III). This DNA damage is characterized by the diminution of supercoiled DNA forms or by the increase of relaxed or linear DNA forms after oxidative attack. The UV spectrum study showed that verbascoside can form complexes with Fe(II) or Fe(III), and the complexation can be reversed by the addition of EDTA. The formation constants of verbascoside-Fe complexes were estimated as 10(21.03) and 10(31.94) M(-2) for Fe(II) and Fe(III) respectively. The inhibition of Fenton reaction by verbascoside could be partially explained by the sequestration of Fe ions.     

巴两橡胶树胶乳黄色体蛋白提取及双向电泳方法初探

巴西橡胶树(Hevea brasiliensis)的黄色体在胶乳凝固和保护植株过程中有重要作用。本文比较使用三氯醋酸/丙酮(TCA/ ACE)、Tris缓冲液、磷酸缓冲液提取橡胶树胶乳黄色体总蛋白的双向电泳效果。确定一种适合双向电泳的蛋白提取方法。结果表明Tris缓冲液提取法得到的双向电泳图谱可以达到300个,尤其是低丰度蛋白呈现性较好,适合提取黄色体蛋白以进行双向电泳。     

Overexpression of HuR, a nuclear-cytoplasmic shuttling protein, increases the in vivo stability of ARE-containing mRNAs.

The messenger RNAs of many proto-oncogenes, cytokines and lymphokines are targeted for rapid degradation through AU-rich elements (AREs) located in their 3'' untranslated regions (UTRs). HuR, a ubiquitously expressed member of the Elav family of RNA binding proteins, exhibits specific affinities for ARE-containing RNA sequences in vitro which correlate with their in vivo decay rates, thereby implicating HuR in the ARE-mediated degradation pathway. We have transiently transfected HuR into mouse L929 cells and observed that overexpression of HuR enhances the stability of beta-globin reporter mRNAs containing either class I or class II AREs. The increase in mRNA stability parallels the level of HuR overexpression, establishing an in vivo role for HuR in mRNA decay. Furthermore, overexpression of HuR deletion mutants lacking RNA recognition motif 3 (RRM 3) does not exert a stabilizing effect, indicating that RRM 3 is important for HuR function. We have also developed polyclonal anti-HuR antibodies. Immunofluorescent staining of HeLa and L929 cells using affinity-purified anti-HuR antibody shows that both endogenous and overexpressed HuR proteins are localized in the nucleus. By forming HeLa-L929 cell heterokaryons, we demonstrate that HuR shuttles between the nucleus and cytoplasm. Thus, HuR may initially bind to ARE-containing mRNAs in the nucleus and provide protection during and after their export to the cytoplasmic compartment.