Analysis of DNA methylation variation in wheat genetic background after alien chromatin introduction based on methylation-sensitive amplification polymorphism

During the process of alien germplasm introduced into wheat genome by chromosome engineering, extensive genetic variations of genome structure and gene expression in recipient could be induced. In this study, we performed GISH （genome in situ hybridization） and AFLP （amplified fragment length polymorphism） on wheat-rye chromosome translocation lines and their parents to detect the identity in genomic structure of different translocation lines. The results showed that the genome primary structure variations were not obviously detected in different translocation lines except the same 1RS chromosome translocation. Methylation sensitive amplification polymorphism （MSAP） analyses on genomic DNA showed that the ratios of fully-methylated sites were significantly increased in translocation lines （CN12, 20.15%; CN17, 20.91%; CN18, 22.42%）, but the ratios of hemimethylated sites were significantly lowered （CN12, 21.41%; CN17, 23.43%; CN18, 22.42%）, whereas 16.37% were fully-methylated and 25.44% were hemimethylated in case of their wheat parent. Twenty-nine classes of methylation patterns were identified in a comparative assay of cytosine methylation patterns between wheat-rye translocation lines and their wheat parent, including 13 hypermethylation patterns （33.74%）, 9 demethylation patterns （22.76%） and 7 uncertain patterns （4.07%）. In further sequence analysis, the alterations of methylation pattern affected both repetitive DNA sequences, such as retrotransposons and tandem repetitive sequences, and low-copy DNA.     

小麦易位系基因组DNA甲基化分析中MSAP体系建立及应用

DNA甲基化在真核生物生长发育过程中起着重要调控作用.依据对DNA甲基化敏感程度不同的同裂酶,在AFLP(amplified fragment length polymorphism)基础上发展而来的MSAP(methylationsensitive amplification polymorphism)技术可以方便的检测全基因组DNA胞嘧啶甲基化模式及程度.本文以一套高代分离的小麦黑麦1RS/1BL易位系及其亲本材料为研究对象,采用EcoRⅠ和HpaⅡ(或MspⅠ)双酶切建立适合于小麦易位系基因组的MSAP技术体系,针对研究中出现的问题提出解决方法,并对酶切位点的甲基化模式进行分析,检测易位系及亲本材料间的甲基化多态性,为进一步的基础研究和育种应用提供理论依据.     

人工诱导虹鳟三倍体的细胞遗传学鉴定

采用一种简便有效的染色体制备方法,成功地制作和观察了人工诱导的三倍体虹鳟(Oncorhynchus mykiss)中期染色体.实验结果表明,虹鳟二倍体的核型2n=60,人工诱导的虹鳟有88%的个体为三倍体,核型3n=90,且大部分都为中着丝粒染色体.     

Epidemic spreading behavior in local-world evolving networks

The susceptible-infected-susceptible （SIS） epidemic model is presented which can be used to study the epidemic spreading behavior in the local-world evolving network model. Local-world evolving model displays a transition from the exponential network to the scale-free network with respect to the connectivity distribution. From theoretical analyses and numerical simulations, we find that the epidemic spreading behavior on local-world networks also takes on some kind of transitional behaviors. The transitional behavior is further verified by comparing the spreading behavior of local-world network with that of random and scale-free networks. Some feasible control strategies are also orooosed to keeo from the eoidemic spreading on networks.     

基于再度感染的SIS传播模型研究

提出了复杂网络上一种基于再度感染的SIS传播模型.在具有树状分支结构的网络中,针对某个染病节点,在考虑其感染子节点的同时,也考查其再次感染祖先节点的情况.分别在小世界网络和无标度网络上进行仿真分析,结果表明,对于小世界网络,基于再度感染的SIS传播模型的稳态感染密度比传统的SIS传播模型的要大,而且感染周期越短,稳态感染密度越大;而对于无标度网络,虽然基于再度感染的SIS传播模型的稳态感染密度也比传统的SIS传播模型的要大,但是,感染周期对于稳态感染密度的影响微乎其微,甚至可以忽略.     

论博尔赫斯小说《女海盗金寡妇》中郑一嫂的故事流传

通过对博尔赫斯小说《女海盗金寡妇》故事载体的写作背景研究,可以确认女海盗郑一嫂的故事并非博尔赫斯的完全杜撰。进一步进行书面渊源的考证可以发现：郑一嫂的故事来源于菲利普.戈斯的《海盗史》对中国清代史料《靖海氛记》的间接转述。郑一嫂的故事流传经历了翻译、改编和作者的再创作的过程。通过对文本的形成变化过程的细节比较可以看出,不同作者的写作目的的变化应该是故事情节变化的直接原因;同时,上一位作者的取舍也在一定程度上影响到了后人的创作。     

Chromosomal localization of the locus PGM (phosphoglucomutase) inDrosophila buzzatii

Summary The locus PGM ofD. buzzatii is localized in the linkage group of chromosome 4, outside the region blocked by the inversion 4s and with a recombination percentage of about 16% from the inversion breakpoint.     

秋水仙素诱导水稻幼穗愈伤组织创制同源四倍体种质的研究

以普通二倍体水稻亲本为材料,用秋水仙素进行水稻的多倍体化诱导,创制同源四倍体水稻三系亲本材料并对其进行鉴定. 结果表明在MS+2,4 D 1.0 mg/L+ KT0.2 mg/L+ IAA0.2 mg/L 和500 mg/L的秋水仙素处理下,水稻愈伤组织染色体加倍效果最好,平均加倍频率可达25.26%.其中,材料CDR22和IR26诱导较易成功,加倍频率分别达到75%和26.5%;相对材料94109 1.3%加倍频率和冈46B 10.8%加倍频率,诱导率差异极显著. 对水稻四倍体材料进行形态学鉴定结果表明     

一种新的无线传感器网络危害传播模型

研究了无线传感器网络中的危害传播问题,提出了一种新的危害传播模型.针对随机图模型存在的不足,利用随机几何图来构造无线传感器网络的拓扑,分析无线传感器网络中的危害传播,并与随机图构造的网络拓扑下的危害传播进行比较.结果表明,采用随机几何图拓扑网络比随机图拓扑网络能够更有效地减缓整个网络的危害爆发.     

舰艇防火分区内火灾蔓延数值模拟

为了建立多舱室间烟气蔓延模型,计算舰艇防火分区内各舱室的火灾烟气温度、高度随时间的变化,并用计算结果指导舰艇防火决策.首先假设防火分区内起火舱室的烟气沉降符合双层区域模型,而烟气经过通风口蔓延到相邻舱室时没有卷吸现象发生;然后运用质量、能量守恒和气体状态方程建立防火分区内多舱室烟气蔓延模型.应用该模型对某舰艇防火分区的按照t2发展的火灾场景进行计算,计算结果比美国的CFAST软件计算的结果略高出10%,主要原因是CFAST中考虑了下层冷空气温度变化.