构树种质资源遗传多样性SRAP分子标记研究

构树（Broussonetia papyrifera L.）为桑科（Moraceae）构树属（Broussonetia）落叶乔木，广泛分布于亚洲东部及太平洋岛屿。它是我国重要的经济林木，具有重要的经济价值，其树皮纤维品质优良，自古就是造纸的优良原料；叶片可用作饲料；果实具有重要的药用价值；环境适应性强，是迅速绿化荒山、荒滩和盐碱地的理想树种。因此对构树这些特性的深入研究和开发利用具有非常重要的实际应用价值。本研究以日本和国内构树主要分布区域的的10种生态型及杂交构树共23份材料，摸索并改进了构树DNA的提取方法，建立了稳定的SRAP分子标记体系，以杂交构树组培苗为材料从120对引物组合中筛选出条带信息较高的17对SRAP引物，以这些引物对23份构树材料进行PCR扩增和标记分析。 本研究取得的主要结果如下： （1）本实验首次将SRAP技术应用于构树的研究中，建立起构树稳定的SRAP-PCR反应体系；实验中对影响扩增的5个主要因素进行了优化，确定20 μL PCR反应体系中各因素最适浓度：模板DNA浓度80 ng/(20 μL)，Mg2+浓度2.0 mM，dNTP浓度0.6 mM，引物浓度0.8 mM，Taq 酶浓度1.5 U/(20 μL)。 （2）从120对引物组合中筛选出来的17对SRAP引物对21份不同生态型构树样本（21份材料指的是除两份杂交构树材料外的其它生态型构树，以下同）进行PCR扩增，共扩增出439条带，平均每对引物25.5条，其大小介于100～1,000 bp之间，其中多态性条带319条，占总数的72.67%。 （3）用Popgene1.32软件进行分析，计算出Shannon信息指数（I）值为0.2275（0.2042），物种水平的Nei基因多样性（H）值为0.1336（0.1436），表明各生态型构树之间的平均遗传多态性不高，中国大陆各生态型构树Shannon信息指数（I）值仅为0.1675（0.2271），物种水平的Nei基因多样性（H）值为0.1039（0.1540），群体遗传多样性较低，构树的遗传分化主要存在于中国和日本之间。 （4）用NTSYS-2.10e软件进行聚类分析，发现不同生态型构树按距离关系远近及分布区域可划分为不同类群。在遗传相似系数0.57附近，对21份材料进行聚类分析发现其可分为两个群体，一类为日本生态型，另一类为中国生态型，表明日本构树与中国野生种构树种源遗传相似性较小。中国各生态型构树在遗传相似系数0.91处可分为5类，总体而言，中国各地区之间的构树遗传相似度较高。对杂交构树分析表明，其亲缘关系与日本构树（母本）更接近。 （5）日本及杂交构树的SCAR标记。本研究找到两条日本及杂交构树的特异性条带，回收、测序，再根据序列往里重新设计引物，转变成稳定性更好，更直观的SCAR标记，这为挑选性状优良的日本及杂交构树提供重要的参考，对其育种有一定的指导意义。其中一条片段经与NCBI数据库比对发现与拟南芥磺基转移酶家族基因具有较高的同源性。

中华鳃(acipenser sinensis)个体间的长度变异与个体内的长度异质性

用技术扩增中华鲜, , 线粒体控制区一时, 发现中华鳃天然群体内存在个体间和个体内的长度变异现象。测序表明, 长度 变异发生在仆靠近月刀的位置, 由长约碱基对的重复序列串联形成 的。由个体内长度变异造成的异质性个体比例为, 非异质性同质性个体的比 例为。非异质性个体间的的大小也不一样, 存在长度变异。在非异质性个体 中, 有、、、个串联重复序列形成的种分子类型的情况, 其重复序列出现的频率从高到低 的循序是一一一。在异质性个体中, 同一个体由种不同分子组合的异质体最普通, 占 。种不同分子组合的频率次之, 占。种不同分子组合的异质体比例最少, 占 。没有发现由种不同分子组合的异质体。对所有异质体混合分析表明, 各种类型的重 复序列出现的比例与非异质体的类似, 即分子大小含重复序列数从高到低的顺序为一 一一一。对尾中华鲜的个体内和个体间的遗传多样性指数分析发现, 有遗传变异 表现在群体内的个体间, 有的遗传变异表现在个体内。由长度异质性造成的个 体内的多样性是中华鲜物种遗传多样性的另一途径。

Genetic evidence for an East Asian origin of domestic dogs

The origin of the domestic dog from wolves has been established, but the number of founding events, as well as where and when these occurred, is not known. To address these questions, we examined the mitochondrial DNA (mtDNA) sequence variation among 654

Pharmacokinetics of sifuvirtide, a novel anti-HIV-1 peptide, in monkeys and its inhibitory concentration in vitro

Aim: To study the pharmacokinetics of sifuvirtide, a novel anti-human immunodeficiency virus (HIV) peptide, in monkeys and to compare the inhibitory concentrations of sifuvirtide and enfuvirtide on HIV-1-infected-cell fusion. Methods: Monkeys received 1.2 mg/kg iv or sc of sifuvirtide. An on-line solid-phase extraction procedure combined with liquid chromatography tandem mass spectrometry (SPELC/MS/MS) was established and applied to determine the concentration of sifuvirtide in monkey plasma. A four-I-127 iodinated peptide was used as an internal standard. Fifty percent inhibitory concentration (IC50) of sifuvirtide on cell fusion was determined by co-cultivation assay. Results: The assay was validated with good precision and accuracy. The calibration curve for sifuvirtide in plasma was linear over a range of 4.88-5000 mu g/L, with correlation coefficients above 0.9923. After iv or sc administration, the observed peak concentrations of sifuvirtide were 10626 +/- 2886 mu g/L and 528 +/- 191 mu g/L, and the terminal elimination half-lives (T,12) were 6.3 +/- 0.9 h and 5.5 +/- 1.0 h, respectively. After sc, T-max was 0.25-2 h, and the absolute bioavailability was 49% +/- 13%. Sifuvirtide inhibited the syncytium formation between HIV-1 chronically infected cells and uninfected cells with an IC50 of 0.33 mu g/L. Conclusion: An on-line SPE-LC/MS/MS approach was established for peptide pharmacokinetic studies. Sifuvirtide was rapidly absorbed subcutaneously into the blood circulation. The T-1/2 of sifuvirtide was remarkably longer than that of its analog, enfuvirtide, reported in healthy monkeys and it conferred a long-term plasma concentration level which was higher than its IC50 in vitro.

云南省鸟类新纪录——反嘴鹬、玉带海雕

2007年12月5日,笔者在云南省香格里拉县纳帕海自然保护区进行水禽调查时发现并拍摄到反嘴鹬Recurvirostra avosetta2只,后又于2009年10月12日,在该县属都湖拍摄到

A review on slip models for gas microflows

Accurate modeling of gas microflow is crucial for the microfluidic devices in MEMS. Gas microflows through these devices are often in the slip and transition flow regimes, characterized by the Knudsen number of the order of 10-2∼100. An increasing number of researchers now dedicate great attention to the developments in the modeling of non-equilibrium boundary conditions in the gas microflows, concentrating on the slip model. In this review, we present various slip models obtained from different theoretical, computational and experimental studies for gas microflows. Correct descriptions of the Knudsen layer effect are of critical importance in modeling and designing of gas microflow systems and in predicting their performances. Theoretical descriptions of the gas-surface interaction and gas-surface molecular interaction models are introduced to describe the boundary conditions. Various methods and techniques for determination of the slip coefficients are reviewed. The review presents the considerable success in the implementation of various slip boundary conditions to extend the Navier-Stokes (N-S) equations into the slip and transition flow regimes. Comparisons of different values and formulations of the first- and second-order slip coefficients and models reveal the discrepancies arising from different definitions in the first-order slip coefficient and various approaches to determine the second-order slip coefficient. In addition, no consensus has been reached on the correct and generalized form of higher-order slip expression. The influences of specific effects, such as effective mean free path of the gas molecules and viscosity, surface roughness, gas composition and tangential momentum accommodation coefficient, on the hybrid slip models for gas microflows are analyzed and discussed. It shows that although the various hybrid slip models are proposed from different viewpoints, they can contribute to N-S equations for capturing the high Knudsen number effects in the slip and transition flow regimes. Future studies are also discussed for improving the understanding of gas microflows and enabling us to exactly predict and actively control gas slip. © Springer-Verlag 2012.

Rhythmic stabilization of periodic orbits in a wedge

The paper addresses the rhythmic stabilization of periodic orbits in a wedge billiard with actuated edges. The output feedback strategy, based on the sole measurement of impact times, results from the combination of a stabilizing state feedback control law and a nonlinear deadbeat state estimator. It is shown that the robustness of both the control law and the observer leads to a simple rhythmic controller achieving a large basin of attraction. Copyright © 2005 IFAC.

Stabilization of periodic orbits in a wedge billiard

This paper introduces a stabilization problem for an elementary impact control system in the plane. The rich dynamical properties of the wedge billiard, combined to the relevance of the associated stabilization problem for feedback control issues in legged robotics make it a valuable benchmark for energy-based stabilization of impact control systems.