A glimpse of life science research at Tsinghua

<正>Life Science at Tsinghua University has a long and eventful history.The Biology Department,founded in 1926,was among the oldest and most prestigious in China.In 1952,the Biology Department,together with other natural science departments,were eliminated from the University by order of the central government.In 1984,the Department of Biological Science and Biotechnology was re-established,with Professor Poo Mu-ming being the founding Director.In the ensuing 25 years,the Department went through rapid transformations and gained national and international recognition.In September 2009,the Department of Biological Science and Biotechnology was replaced by the School of Life Sciences.     

Collagen scaffolds modified with collagen-binding bFGF promotes the neural regeneration in a rat hemisected spinal cord injury model

Nerve conduit is one of strategies for spine cord injury(SCI)treatment.Recently,studies showed that biomaterials could guide the neurite growth and promote axon regeneration at the injury site.However,the scaffold by itself was difficult to meet the need of SCI functional recovery.The basic fibroblast growth factor(bFGF)administration significantly promotes functional recovery after organ injuries.Here,using a rat model of T9 hemisected SCI,we aimed at assessing the repair capacity of implantation of collagen scaffold(CS)modified by collagen binding bFGF(CBD-bFGF).The results showed that CS combined with CBD-bFGF treatment improved survival rates after the lateral hemisection SCI.The CS/CBD-bFGF group showed more significant improvements in motor than the simply CS-implanted and untreated control group,when evaluated by the 21-point Basso-Beattie-Bresnahan(BBB)score and footprint analysis.Both hematoxylin and eosin(H&E)and immunohistochemical staining of neurofilament(NF)and glial fibrillary acidic protein(GFAP)demonstrated that fibers were guided to grow through the implants.These findings indicated that administration of CS modified with CBD-bFGF could promote spinal cord regeneration and functional recovery.     

不同控制模式对毕赤酵母表达IL-2-HSA的比较研究

以溶氧（DO）和甲醇浓度作为控制指标,分别考察了诱导表达阶段DO和甲醇浓度对毕赤酵母高密度发酵表达白介素-2-白蛋白融合蛋白（IL-2-HSA）的影响。通过实验比较得出：诱导阶段控制DO对IL-2-HSA表达影响不明显,而甲醇浓度对IL-2-HSA影响很大。高甲醇浓度（15～25g／L）有利于IL-2-HSA的表达,发酵结束时的表达量约是低甲醇浓度（5～8g／L）诱导下的2倍。此外,在诱导阶段,通过限制性添加甘油可以有效提高菌体的呼吸活性,促进菌体生长。     

利用文本提取工具构建乳杆菌肽聚糖特异性免疫调节网络

目的探索乳杆菌肽聚糖免疫调节作用的机制。方法BALB／c小鼠腹腔注射乳杆菌肽聚糖,从腹腔巨噬细胞和脾淋巴细胞提取RNA,基因芯片分析基因表达情况,利用Medscan从pubmed文献摘要提取肽聚糖相关基因网络,映射芯片数据获得乳杆菌肽聚糖特异基因网络。结果乳杆菌肽聚糖主要通过TLR2-NF-κB信号通路激活炎性细胞因子的表达,但是PGRP-L可能通过降解肽聚糖对此通路有负调节作用,NF-κB的激活可能诱导NOD2表达,对此通路进行负调节。结论乳杆菌肽聚糖通过与多种受体作用诱导独特的免疫反应,维持机体免疫稳态。     

DXS6804/DXS9896/GATA144D04基因座在中国汉族群体中的遗传多态性及其法医学应用Genetic

为了调查X染色体上DXS6804、DXS9896和 GATA144D04等3个STR基因座在中国汉族群体的遗传多态性及其法医学应用价值,来用PCR和聚丙烯酰胺凝胶电泳对X染色体3个STR基因座进行分型,并检验女性基因型频率分布是否符合Hardy-Weinberg平衡,计算法医学常用各种概率。DXS6804、DXS9896和 GATA144D04的非父排除率分别为0.5990、0.6220、0.4280,表明3个STR基因座在中国汉族群体均具有遗传多态性,χ2检验表明女性的基因型频率分布符合Hardy-Weinberg平衡。X染色体上的基因座DXS6804、DXS9896和 GATA144D04在中国汉族群体中具有较高的遗传多态性,可应用于法医学检验和群体遗传学分析。 Abstract： To investigate the genetic polymorphisms of three short tandem repeats loci of chromosome X in Chinese Han population in Chengdu area and its use in forensic science. Three X-chromosome linked short tandom repeat loci were analyzed by PCR followed by polyacrylamide gel electrophoresis. Hardy-Weinberg equilibrium was tested and forensic interested value was calculated .The power of exlcution of DXS6804、DXS9896和 GATA144D04 is 0.5990、0.6220、0.4280,respectively. The result showed that all the three STR loci were polymorphic among 100 unrelated females and 120 unrelated males from Chinese Han population. χ2 tests demonstrated that genotype frequencies in females did not depart from Hardy-Weinberg equilibrium. Three X-chromosome linked short tandem repeat loci have high polymorphism, they can be applied to forensic medicine and population genetics.     

Critical Role of Cys168 in Noggin Protein's Biological Function

Previous studies have indicated that noggin exerts its neural inducing effect by binding andantagonizing bone morphogenetic protein 4(BMP4).In order to further clarify the relationship between thestructure and the function of noggin,and elucidate the possible mechanism responsible for noggin-BMP4interaction,we generated three noggin mutants,C168S,C174S and C197S,by using a site-directed mu-tagenesis method.Ectopic expression of wild-type(WT)noggin,C174S or C197S,in Xenopus animal caps(ACs)by mRNA injection converted the explants(prospective ectoderm)into neural tissue,as indicated bythe neural-like morphology and expression of the neural cell adhesion molecule(NCAM)in the ACs.Incontrast,ACs expressing C 168S suffered an epidermal fate similar to the control caps.Similarly,among the threemutants,only C 168S lost the dorsalizing function.These studies highlight the critical role played by Cys168in noggin's biological activities.It probably participates in the formation of an intermolecular disulfide bridge.     

二棱大麦数量性状相关遗传力和选择指数的分析

以15个二棱大麦品种(系)材料,用相关遗传力研究大麦数量性状的相关遗传,并计算分析籽粒产量和产量构成性状所组合的各种选择指数。结果表明:各性状与单株粒重的相关遗传力均低于单株粒重的遗传力,故仅利用一个性状作间接选择的效率比对单株粒重作直接选择的效率低;在构成大麦产量的三要素中,着重提高单株穗数对产量的选择效率最大; 高产育种同时考虑与产量显著相关的性状比单纯对产量选择的效果好,其中以单株穗数、每穗粒数和籽粒产量结合起来选择的效果最佳。本文并对相关遗传力在相关遗传变异分析中的应用进行了讨论。     

Species identification refined by molecular scatology in a community of sympatric carnivores in Xinjiang,China

Many ecological studies and conservation management plans employ noninvasive scat sampling based on the assumption that species’ scats can be correctly identified in the field. However, in habitats with sympatric similarly sized carnivores, misidentification of scats is frequent and can lead to bias in research results. To address the scat identification dilemma, molecular scatology techniques have been developed to extract DNA from the donor cells present on the outer lining of the scat samples. A total of 100 samples were collected in the winter of 2009 and 2011 in Taxkorgan region of Xinjiang, China. DNA was extracted successfully from 88% of samples and genetic species identification showed that more than half the scats identified in the field as snow leopard(Panthera uncia) actually belonged to fox(Vulpes vulpes). Correlation between scat characteristics and species were investigated, showing that diameter and dry weight of the scat were significantly different between the species. However it was not possible to define a precise range of values for each species because of extensive overlap between the morphological values. This preliminary study confirms that identification of snow leopard feces in the field is misleading. Research that relies upon scat samples to assess distribution or diet of the snow leopard should therefore employ molecular scatology techniques. These methods are financially accessible and employ relatively simple laboratory procedures that can give an indisputable response to species identification from scats.