Effects of oriented substrates on cell morphology, the cell cycle, and the cytoskeleton in Ros 17/2.8 cells

Absence of gravity or microgravity influences the cellular functions of bone forming osteoblasts. The underlying mechanism, however, of cellular sensing and responding to the gravity vector is poorly understood. This work quantified the impact of vector-directional gravity on the biological responses of Ros 17/2.8 cells grown on upward-, downward- or edge-on-oriented substrates. Cell morphology and nuclear translocation, cell proliferation and the cell cycle, and cytoskeletal reorganization were found to vary significantly in the three orientations. All of the responses were duration-dependent. These results provide a new insight into understanding how osteoblasts respond to static vector-directional gravity.

来自易变山羊草抗禾谷孢囊线虫基因的克隆与序列分析

禾谷孢囊线虫（Heterodera avenae）是严重危害禾谷类作物的病原线虫之一,它广泛分布于澳大利亚、欧洲、北美、印度和中国等世界主要小麦产区,使作物严重减产,造成巨大的经济损失。目前最有效的防治措施之一是将外源抗性基因导入栽培小麦(Triticum aestivum L.)，培育抗禾谷孢囊线虫的新品种。但迄今为止抗禾谷孢囊线虫基因克隆研究的相关报道却很少。 本实验根据此前从抗禾谷孢囊线虫材料E-10扩增得到的与来自节节麦（Aegilops tauschii）的抗禾谷孢囊线虫基因Cre3高度同源的序列Rccn4,设计出三条嵌套引物,采用SON-PCR(single oligonucleotide nested PCR)方法,从E-10基因组DNA中得到一个长为1264 bp的扩增产物(命名为Rccn-L),测序比对结果显示,这一序列将Rccn4的3’端延伸了1209 bp,与抗禾谷孢囊线虫Cre3基因核苷酸同源性为86﹪，核苷酸编码区长1026 bp，含一个不完整的开放阅读框,一个终止密码子，没有起始密码子和内含子结构,编码一个342个氨基酸残基的蛋白质。该蛋白质等电点为5.19，分子量为38112.6Da。从序列的第113位开始到第332位是NBS-LRR类抗病性基因LRR区,呈现XXLXXLXXL重复。LRR编码区内亮氨酸残基的含量达17﹪，与抗禾谷孢囊线虫Cre3基因LRR编码区的核苷酸和氨基酸同源性分别为89﹪和78﹪。本实验首次将SON-PCR成功地运用于植物基因克隆，为植物基因克隆提供了又一有效方法。 此外,还根据Cre3基因及其他的NBS-LRR类植物抗性基因的NBS和LRR区保守序列设计了两对特异性引物，从禾谷孢囊线虫抗性材料易变山羊草基因组DNA中扩增到两个相应的目标条带。测序分析结果表明，它们的长度分别为532bp和1175bp，构成了一个有32bp的共同序列的NBS-LRR编码区。其序列总长为1675bp（命名为RCCN），含有一个不完整的开放阅读框，没有起始密码子、终止密码子和内含子结构。其中编码序列为1673bp，可编码一个557个氨基酸的蛋白质，等电点（pI）为5.39，分子量为63537.5Da。与Cre3的核苷酸和氨基酸同源性分别为87.8﹪和77﹪。RCCN氨基酸序列中含有已知抗病基因NBS区域的几个保守模体：kinase2区的ILDD、kinase3的（ⅰ）ESKILVTTRSK，（ⅱ）KGSPLAARTVGG，（ⅲ）RRCFAYCS及EGF。RCCN NBS区与Cre3 NBS区的核苷酸和氨基酸的同源性分别为96.4﹪和94﹪。从氨基酸序列的274位到548位为LRR保守区，呈现不规则的aXXLXXLXXL（其中a代表I，V，L，F或M）重复，其中亮氨酸的含量为15.6﹪。该区域与Cre3的LRR区的核苷酸和氨基酸同源性分别为80.8﹪和74﹪。推测该序列可能为一个抗禾谷孢囊线虫的新基因。 本文对抗禾谷孢囊线虫基因的克隆研究，为进一步克隆基因全序列，探索其结构与功能，和研究该基因表达与调控提供了关键信息。同时也为通过基因工程途径将抗性基因向优良小麦品种高效、定向转移，最终培育出小麦抗禾谷孢囊线虫新品种奠定了基础。 Cereal cyst nematode (CCN) is a damaging pathogen of broad acre cereal crops in Australia, Europe, North America, India and China. It affects wheat, barley, oat and triticale and causes yield loss of up to 80%. At present, Transferring resistance genes against CCN into wheat cultivars and breeding varieties are considered one of the most effective methods for controlling the CCN. However, there are very limited reports concerning the cloning studies of resistance genes against the cereal cyst nematode. According to the sequence of Rccn4 which had high similarity to the nucleotide binding site (NBS) coding region of cereal cyst nematode resistance gene, Cre3， We designed three 3’ nested primers. Using single oligonucleotide nested PCR (SON-PCR) we successfully amplified one band, Rccn-L, of 1264bp from E-10 which is the wheat-Ae.variabilis translocation line containing the cereal cyst nematode resistance gene of Ae.variabilis. We found that this band of interesting is the 3’ flanking sequence of 1209bp in size of Rccn4. The coding region was 1026bp, which contained an incomplete open reading frame and a terminator codon, without initiation codon and intron, encoding a peptide of 342 amino acid residues, and shared 86﹪nucleotide sequence identity with Cre3. This peptide had a conserved LRR domain, containing the imperfect repeats,XXLXXLXXL, which contains 17﹪ leucine residues and shares, respectively, 89﹪ nucleotide sequence and 78﹪ amino acid sequence identity with the LRR sequence of Cre3 locus. This research firstly used SON-PCR in the research of plant genome successfully, which indicated that SON-PCR is another method of cloning plant gene. At the same time, According to the conversed motif of NBS and LRR region of cereal cyst nematode resistance gene Cre3 from wild wheat (Triticum tauschlii L.) and the known NBS-LRR group resistance genes, we designed two pairs of specific primers for NBS and LRR region respectively. One band of approximately 530bp was amplified using the specific primers for conversed NBS region and one band of approximately 1200bp was amplified with the specific primers for conversed LRR region. After sequencing, we found that these two sequences included 32bp common nucleotide sequence and have 1675 bp in total, which was registered as RCCN in the Genbank. RCCN contained a NBS-LRR domain and an incomplete open reading frame without initiation codon, terminator codon and inxon. Its exon encodes a peptide of 557 amino acid residues. The molecular weight of the protein from the amino acid was 63.537 KDa. The amino acid sequence of RCCN contained conserved motif: ILDD, ESKILVTTRSK, KGSPLAARTVGG, RRCFAYCS, EGF，LRR. RCCN shares 87.8﹪ nucleotide sequence and 77﹪ amino acid sequence identity with cereal cyst nematode gene Cre3. It might be a novel cereal cyst nematode resistance gene. These research results of cloning the resistance genes against cereal cyst nematode bring a great promise for transferring resistance genes into wheat cultivars and breeding new wheat varieties against cereal cyst nematode by gene engineering. And these results also lay the hard foundation for the expressing researches of these genes.

激发态~(17)Ne双质子2p发射的实验

<正>在中国科学院近代物理研究所放射性束流装置RIBLL上完成了17Ne+197Au的实验,采用硅条探测器与CsI(Tl)+PIN探测器阵列进行运动学完全测量,研究了17Ne双质子发射的机制。实验选用

~(17)B的晕结构特征

实验利用束流衰减法测量了43.7AMeV丰中子核17B与C靶反应的总截面σR=(1724±93)mb.用零程Glauber计算,假定17B具有核芯15B和两个价中子结构,输入GG和GO密度分布,计算的激发函数曲线与该实验数据很好符合,输入描述稳定核双参数Fermi密度分布,不能得到与实验数据符合的结果,表明17B是核芯15B+2n的假定是合理的.并且中子密度分布表现较大空间扩展-晕结构特征.

丰中子奇异核~(17)B的实验研究

在兰州重离子加速器国家实验室(HIRFL)放射性次级束流线(RIBLL)上,用束流透射法测量了丰中子奇异核17B与C靶反应的总截面.假定17B具有15B(核芯)+2n结构,采用Gauss+HO形式的密度分布和零力程Glauber模型进行计算的结果可以很好地拟合实验数据,并得出17B的密度分布有一个很大的弥散,表明17B是双中子晕核.

小角度范围内弱束缚核~(17)F弹性散射微分截面的奇异行为(英文)

在兰州放射性束流线(RIBLL)上完成了17F／17O+208Pb的弹性散射微分截面角分布测量．分析了17F／17O弹性散射产物微分截面的对数(ln(dσ／dθ))随散射角平方(θ2)的依赖关系．结果表明,在所测量的角度范围内(6°-20°),17O的这一依赖关系可以用一条直线很好地拟合,而17F的这一依赖关系需要两条不同斜率的直线才能拟合．17F数据拟合中的这种斜率改变可能起因于17F的奇异结构．对其他实验组数据的分析支持以上的结论,即在一定的角度范围内,弱束缚核与稳定核相比,弹性散射产物微分截面的对数与散射角平方的依赖关系有明显的差异,这可以作为深入研究“晕核”和“皮核”的一个新探针．

质子滴线核~(17)Ne在Si靶上反应总截面的测量

描述了在兰州放射性次级束流线上用 80MeV/u的2 0 Ne轰击Be靶产生出理论上预言有奇异结构的17Ne的次级束流 ,并用它轰击Si靶 ,测量它的反应总截面并与其相邻的核相比较 ,发现截面值没有增大的现象 .利用微观的Glauber模型进行了计算 ,理论计算和实验结果符合很好 ,确认其没有奇异结构 .

Mid-Holocene climate variations recorded by palaeolake in marginal area of east Asian monsoon: A multi-proxy study

IEECAS SKLLQG

高电荷态离子Ar~(17+)与Mo表面作用过程中的X射线发射

观测了低速 (小于Bohr速度 )高电荷Ar17+离子与金属Mo表面相互作用的X射线发射 ,以及ArKα ,KβX射线强度随入射离子动能的变化 .

~(17)N+~(197)Au反应中碎片与中子的符合测量

在 3 3 .4MeV/u17N束轰击197Au靶产生的反应中 ,利用放置于不同角度组合的 1 7个中子探测器 ( 4°— 83°)和 1 4个半导体望远镜 ( 2 .3°— 9.0°)对反应产物碎片与中子进行了符合测量 .经对所得实验角分布积分得到Z =3— 6元素的同位素产额分布 .在参加者 -旁观者模型框架下 ,采用17N原子核内部的不同密度分布计算了同位素产额分布并与实验数据做比较

~(17)F和~(18)Ne与质子的弹性散射角分布

采用逆运动学方法对放射性核束17F和18Ne与质子进行弹性散射实验 ,得到了实验测量微分截面 .用较准确描述放射性核素性质的CH89参数化的光学势为初始光学势 ,用扭曲波玻恩近似的理论计算程序DWUCK4和自动参数搜索程序ABOD对实验数据进行光学势参数理论拟合 ,得到了与实验数据相符合的光学势参数 .将得到的光学势参数进行分析 ,得到了17F和18Ne实势相互作用均方根半径分别为 3 2 3 9fm和 3 3 1 7fm .