八肽胆囊收缩素对内毒素休克时海马损伤的影响及其机制初探

目的：观察八肽胆囊收缩素（CCK-8）对内毒素休克（ES）时海马损伤的影响,并探讨其可能的作用机制。方法：将日本大耳白兔经静脉注入内毒素的主要活性成分脂多糖（LPS,8mg／kg）复制ES模型。动物（32只）随机分为对照组、LPS组、CCK-8＋LPS组和非特异性CCK受体拮抗剂丙谷胺（Pro）＋LPS组（n=8）。监测平均动脉压（MAP）的变化,光、电镜观察海马的组织形态学改变,比色法检测海马NOS和SOD活性、N0和MDA含量的改变．用SD大鼠（12只,同上复制模型及分组）以免疫组织化学染色法观察海马iNOS和nNOS表达的变化。结果：与对照组相比,注入LPS后出现MAP显著而持续下降（P〈0．01）;海马部位神经元损伤明显;iNOS和nNOS表达增强,NOS活性、NO和MDA含量显著升高（P〈0．05、P〈0．01和P〈0．01）,SOD活性则降低（P〈0．01）。预先注入CCK-8可明显减轻上述变化,预先注入Pro则加剧以上变化。结论：CCK-8可减轻ES时脑内海马部位的损伤。其机制可能与其抗氧化作用和抑制NO的过量生成有关。     

麻疯树脂酶全长基因克隆、表达及其蛋白质结构预测

脂酶(Lipase,EC3.1.1.3)是普遍应用于皮革、饲料及生物柴油工业的工业酶制剂,具有广泛的应用价值。目前对植物来源的脂酶研究较少。本研究用在生物柴油中具有应用前景的油料植物——麻疯树(Jatrophacurcas)作为研究对象,克隆了该物种的脂酶基因(JcLIP)。通过多序列比对并结合物种的亲缘关系设计了具有较高特异性的简并引物,通过使用RT-PCR和RACE技术,最终获得了麻疯树脂酶基因的全长序列并成功地在大肠杆菌中表达,酶活测定结果表明,麻疯树脂酶在大肠杆菌中表达在包涵体中,但是能产生具有活力的蛋白质,酶活约为0.8U.mL-1。结构预测和比较表明,JcLIP蛋白质具有脂酶的结构核心和催化活性中心,而在非核心区具有较毛霉脂酶更多的插入和随机卷曲,这可能是决定二者之间酶活差异的重要原因。     

Morphology and Phase Behavior of Two-Component Lipid Membranes

The stability and shapes of domains with different bending rigidities in lipid membranes are investigated. These domains can be formed from the inclusion of an impurity in a lipid membrane or from the phase separation within the membrane. We show that, for weak line tensions, surface tensions and finite spontaneous curvatures, an equilibrium phase of protruding circular domains or striped domains may be obtained. We also predict a possible phase transition between the investigated morphologies.     

Low Divergence of Clonorchis sinensis in China Based on Multilocus Analysis

Clonorchis sinensis, an ancient parasite that infects a number of piscivorous mammals, attracts significant public health interest due to zoonotic exposure risks in Asia. The available studies are insufficient to reflect the prevalence, geographic distribution, and intraspecific genetic diversity of C. sinensis in endemic areas. Here, a multilocus analysis based on eight genes (ITS1, act, tub, ef-1a, cox1, cox3, nad4 and nad5 [4.986 kb]) was employed to explore the intra-species genetic construction of C. sinensis in China. Two hundred and fifty-six C. sinensis isolates were obtained from environmental reservoirs from 17 provinces of China. A total of 254 recognized Multilocus Types (MSTs) showed high diversity among these isolates using multilocus analysis. The comparison analysis of nuclear and mitochondrial phylogeny supports separate clusters in a nuclear dendrogram. Genetic differentiation analysis of three clusters (A, B, and C) showed low divergence within populations. Most isolates from clusters B and C are geographically limited to central China, while cluster A is extraordinarily genetically diverse. Further genetic analyses between different geographic distributions, water bodies and hosts support the low population divergence. The latter haplotype analyses were consistent with the phylogenetic and genetic differentiation results. A recombination network based on concatenated sequences showed a concentrated linkage recombination population in cox1, cox3, nad4 and nad5, with spatial structuring in ITS1. Coupled with the history record and archaeological evidence of C. sinensis infection in mummified desiccated feces, these data point to an ancient origin of C. sinensis in China. In conclusion, we present a likely phylogenetic structure of the C. sinensis population in mainland China, highlighting its possible tendency for biogeographic expansion. Meanwhile, ITS1 was found to be an effective marker for tracking C. sinensis infection worldwide. Thus, the present study improves our understanding of the global epidemiology and evolution of C. sinensis.     

Ex vivo expansion of umbilical cord blood

The efficacy of cord blood (CB) transplantation is limited by the low cell dose available. Low cell doses at transplant are correlated with delayed engraftment, prolonged neutropenia and thrombocytopenia and elevated risk of graft failure. To potentially improve the efficacy of CB transplantation, approaches have been taken to increase the cell dose available. One approach is the transplantation of multiple cord units, another the use of ex vivo expansion. Evidence for a functional and phenotypic heterogeneity exists within the HSC population and one concern associated with ex vivo expansion is that the expansion of lower 'quality' hematopoietic progenitor cells (HPC) occurs at the expense of higher 'quality' HPC, thereby impacting the reserve of the graft. There is evidence that this is a valid concern while other evidence suggests that higher quality HPC are preserved and not exhausted. Currently, ex vivo expansion processes include: (1) liquid expansion: CD34+ or CD133+ cells are selected and cultured in medium containing factors targeting the proliferation and self-renewal of primitive hematopoietic progenitors; (2) co-culture expansion: unmanipulated CB cells are cultured with stromal components of the hematopoietic microenvironment, specifically mesenchymal stem cells (MSC), in medium containing growth factors; and (3) continuous perfusion: CB HPC are cultured with growth factors in 'bioreactors' rather than in static cultures. These approaches are discussed. Ultimately, the goal of ex vivo expansion is to increase the available dose of the CB cells responsible for successful engraftment, thereby reducing the time to engraftment and reducing the risk of graft failure.     

甜杨低温响应microRNAs的克隆与分析

MicroRNAs (miRNAs)作为一类21碱基左右的非编码小RNAs,参与植物生长发育的调控,并在植物对生物与非生物胁迫的应答过程中发挥重要作用.本研究依据miRNA高度保守特点,利用已公布的毛果杨(Populus trichocarpa)基因组序列设计引物,从甜杨(Populus suaveolens)基因组中克隆获得了12个miRNA基因座序列.序列比对结果表明,这些miRNA基因均为毛果杨低温响应miRNA基因的同源序列.同时,以低温(0℃)处理0～48 h的甜杨幼苗为试材,通过半定量RT-PCR法对miRNA基因的成熟体序列在不同处理时间下的表达谱进行分析,结果显示,大多数miRNA成熟体序列在甜杨低温胁迫下的表达模式与其在毛果杨中的表达极为相似,由此可推测这些保守性miRNAs可能在甜杨和毛果杨两物种对低温胁迫的应答反应中发挥相似的功能,而miR168a、miR168b和miR475a在两物种间表达现象的差异,表明它们可能通过调控多种靶基因而发挥不同作用.本文结果将为进一步研究甜杨基因功能提供基础.     

中国葡萄属植物叶片气孔特征的研究

对起源于中国的葡萄属(Vitis L.)20个种或变种叶片气孔特性进行了观察研究。结果表明:气孔纵径对葡萄属种的分类有较大的价值;气孔比密度(叶片上所有气孔复合体面积与叶片面积之比)与叶片大小呈极显著正相关;气孔密度与气孔纵径呈极显著负相关;所有观察种类的叶片气孔类型均为不规则型。     

单粒干燥大豆种子基因组DNA提取的有效方法

大豆基因组DNA的提取是进行大豆分子生物学研究的基础.以大豆干燥的种子为材料,将SDS法和CTAB法结合在一起并进行了一定的改进,有效的提取了基因组DNA.通过电泳、紫外分光光度计检测和ISSR标记分析验证这种方法是提取大豆干种子基因组DNA的有效方法.     

Depletion of activated hepatic stellate cell correlates with severe liver damage and abnormal liver regeneration in acetaminophen-induced liver injury

Hepatic stellate cells (HSCs) are important part of the local 'stem cell niche' for hepatic progenitor cells (HPCs) and hepatocytes. However, it is unclear as to whether the products of activated HSCs are required to attenuate hepatocyte injury, enhance liver regeneration, or both. In this study, we performed 'loss of function' studies by depleting activated HSCs with gliotoxin. It was demonstrated that a significantly severe liver damage and declined survival rate were correlated with depletion of activated HSCs. Furthermore, diminishing HSC activation resulted in a 3-fold increase in hepatocyte apoptosis and a 66% decrease in the number of proliferating hepatocytes. This was accompanied by a dramatic decrease in the expression levels of five genes known to be up-regulated during hepatocyte replication. In particular, it was found that depletion of activated HSCs inhibited oval cell reaction that was confirmed by decreased numbers of Pank-positive cells around the portal tracts and lowered gene expression level of cytokeratin 19 (CK19) in gliotoxin-treated liver. These data provide clear evidence that the activated HSCs are involved in both hepatocyte death and proliferation of hepatocytes and HPCs in acetaminophen (APAP)-induced acute liver injury.