论《史记》“同心圆”式传记结构法

司马迁撰写《史记》时,深知“谋篇布势,是一段最大功夫”。而本文论及的《史记》人物传记的“同心圆”式结构,便是他独具匠心的精巧布局之一。“同心圆”在几何学中是指同一平面上圆心相重合而半径不同的圆。在此则借指为司马迁构思传记结构的一条规律性笔法。其特征为:人物传记开篇先以精当的素描方法勾勒出传主发迹之初的一段生活轶事或性格特征。细琐小事,生活插曲,看似闲笔。然后,继之以长篇叙写,详言传主一生大是大非,成败荣枯之事。篇首素描即如“同心圆”之内圆。篇中详叙即如“同心圆”之外圆。这二者被司马迁牢牢固定在对传主一生评价的历史圆心上。内圆是外圆性格衍生的基因,外圆则是其性格基因的逻辑延伸。

生动如歌的作家传记——读《不醉不说 乔羽的大河之恋》

传记作家周长行在继《乔羽"恋"歌》(1999年出版)之后,于2007年又创作了风格迥异的《不醉不说乔羽的大河之恋》,给读者还原了一个更加真实而有个性的乔羽形象。作者采用生动有趣的文字表达方式,平民化的语言将名人的距离与读者拉近,使读者获得一种畅快的阅读感受,让读者更加接近乔羽的凡人一面,立体鲜活的传主形象在书中呼之欲出。与《乔羽"恋"歌》相比较,《不醉不说》在文体结构和内容上都有很大的改进和创新,除了每一章末尾的乔羽采访实录"不醉不说"是其特有之外,作者对传记内容也进行了全面改进,对乔羽生平的表述更加科学,将《乔羽恋歌》中部分内容进行了删减的同时增加了大量的新内容。

Population Genetic Structure in Apricot (Prunus armeniaca L.) Cultivars Revealed by Fluorescent-AFLP Markers in Southern Xinjiang,China

Population-wide genetic structure was studied using fluorescent-AFLP markers on 85 apricot （Prunus armeniaca L.） cultivars collected from Kuche, Kashi, Hetian in the Tarim Basin, southern Xinjiang Uygur Autonomous Region of China. The purpose of this study was to determine the genetic structure and genotypic diversity among the different eco-geographical populations. Based on the results from this study, 8 pairs of fluorescent-AFLP primers showed clear electrophoregram and high polymorphism amongst the 64 pairs of EcoR Ⅰ/Mse Ⅰ （Mse Ⅰ - a FAM fluorescent marked primer） primers screened. There was a significant polymorphic difference for the same primer pair in different populations and for the same population with different primer pairs. The percentage of polymorphic loci （P） at species level was higher than Kuche, Hetian, Kashi population levels, respectively. The Nei＇s gene diversity index （H） and Shannon＇s information index （I） at species level were higher than those of Kuche, Hetian, and Kashi at population level, respectively. H and I of Kuche population were the highest amongst the three populations. Apricot population genetic diversity was found mainly within the population, Genetic differentiation coefficient between populations （GST） was 0.0882. Gene flow Nm between the populations was 5.1689. Population genetic identity was between 0.9772-0.9811 and genetic distance was between 0.0191-0.0232. These results further indicated that the similarity between populations was higher and the genetic distance between populations was smaller. The UPGMA cluster analysis indicates that the geographical populations at Kuche, Kashi, Hetian were relatively independent Mendelian populations. Concurrently, there was also partial gene exchange between the populations. All the evidences indicated that the genetic diversity in Kuche population was the highest, suggesting that it could be a transition population from wild apricot to cultivated apricot. There were abundant genetic diversities in apricot cultivar populations in southern Xinjiang, China, which provide promising germplasm for further breeding and theoretical basis for biodiversity conservation and utilization for apricot population in this area.

Genetic Structure of Malus sieversii Population from Xinjiang,China,Revealed by SSR Markers

One hundred and nine Malus sieversii accessions from four geographical populations located at Kuerdening in Mohe town, Gongliu County, Jiaowutuohai, in Xinyuan County, Daxigou in Houcheng County of Ily State, and Baerluke Mountain in Yumin County of Tacheng State, Xinjiang Uygur Autonomous Region of China were studied by SSR markers. The purpose of the study was to determine the genetic structure and diversity in these eco-geographical populations with eight pair SSR primers of apple. The results indicated that： an average of 16 bands was detected in the four populations. The percentage of polymorphic bands in Gongliu population （89.06%） was the highest in the four populations. The average Nei＇s gene diversity index was 0.257 for all the loci. Totally, 128 polymorphic loci were detected and the percentage of polymorphic loci （P） was 100%, 88.28%, 84.83%, 87.50%, and 87.12%, respectively, at the species level and Gongliu, Xinyuan, Huocheng, and Yumin population levels. The Nei＇s gene diversity index （H = 0.2619） and Shannon＇s information index （1 = 0.4082） in the species level were higher than in the population level. The Nei＇s gene diversity index and Shannon＇s information index in the four populations were Gongliu 〉 Huocheng 〉 Xinyuan 〉 Yumin. Gongliu population and Xinyuan population were the highest in genetic identity and the closest in genetic distance. Gene flow between the populations was 7.265 based on genetic differentiation coefficient （GST = 0.064）. The UPGMA cluster analysis indicated that the genetic relationships between the Gongliu and Xinyuan population were the closest, and the Yumin population were the farthest with the other three populations. The UPGMA cluster analysis indicated that the four geographical populations located in Gongliu, Xinyuan, Huocheng, and Yumin were relatively independent populations. Concurrently, there was also mild gene exchange between the populations. On the basis of the study of population genetic structure and the highest genetic diversity, Gongliu population should be given a high priority consideration in Malus sieversii population＇s in situ germplasm conservation.

The comparison between allozyme and RAPD makers for the population genetic structure analysis of scallop Chlamys farreri

To compare genetic markers for population genetics analysis, allozyme electrophoresis and random amplified polymorphic DNA （RAPD） were used to detect the genetic structure of scallop Chlamysfarreri population. Thirteen enzymes （MDH, ME, IDH, GPI, PGM, PEP-LG, PEP-pp, ACP, AK, PK, AAT, SOD, EST） in three butter systems （TC, pH6.9; TMME, pH 7.4; and EBT, pHS.9） were selected and 22 loci were used for the analysis, among them 7 loci （Gpi, Pgm, Pep.m-l, Pep.pp. Aat-2, Est-2, Est-3） were polymorphic which attributed 31.82% to the total. The average of heterozygosity was 0.113 and most of the studied loci showed heterozygote deficiencies. The same specimens were investigated using 10 arbitrarily selected primers （10-base）. Twenty two of 54 RAPD fragments were polymorphic with average heterozygosity of 0.194. The result indicated that the two types of markers reflected a consistent trend in the parameter values of genetic diversity of the population, but RAPD revealed more information of genetic variation than allozyme electrophoresis.

Coordinated regulation of active and repressive histone methylations by a dual-specificity histone demethylase ceKDM7A from Caenorhabditis elegans

H3K9me2 and H3K27me2 are important epigenetic marks associated with transcription repression, while H3K4me3 is associated with transcription activation. It has been shown that active and repressive histone methylations distribute in a mutually exclusive manner, but the underlying mechanism was poorly understood. Here we identified ceKDM7A, a PHD （plant homeodomain）- and JmjC domain-containing protein, as a histone demethylase specific for H3K9me2 and H3K27me2. We further demonstrated that the PHD domain of ceKDM7A bound H3K4me3 and H3K4me3 co-localized with ceKDM7A at the genome-wide level. Disruption of the PHD domain binding to H3K4me3 reduced the demethylase activity in vivo, and loss of ceKDM7A reduced the expression of its associated target genes. These results indicate that ceKDM7A is recruited to the promoter to demethylate H3K9me2 and H3K27me2 and activate gene expression through the binding of the PHD domain to H3K4me3. Thus, our study identifies a dual-specificity histone demethylase and provides novel insights into the regulation of histone methylation.

The analysis of Wang Anshi＇s prose named ＂reading ＇The biography of Meng Changjun＇＂

The paper has analysed on Wang Anshi＇ s prose named ＂reading ＇The biography of Meng Changjun＇ ＂ comprehensively and objectively. It points out that there are three characteristics in it. The first characteristic is the innovative conception, and the profound sustenance. The second characteristic is the concise style and the tight structure. And the third characteristic is that there are some deviations in the logic and ideas.