铁屑修复地浸采铀地下水中硝酸盐污染的研究

以废铁屑为原料,对地浸采铀地下水中的硝酸盐氮污染进行修复实验,研究了溶液pH、地下水中主要共存离子以及不同柱填料对NO-3-N去除率的影响,同时结合粉煤灰预处理技术,对实验条件下铁屑去除硝酸盐的污染进行了探讨。结果表明:铁屑可有效去除地下水中的NO-3-N,其去除率随pH的降低而逐渐升高;溶液中共存的Ca2 、Mg2 对NO-3-N的去除影响不大,而SO42-、HCO-3的存在可明显降低NO-3-N去除效果;实验室条件下,单独采用铁屑去除地浸采铀地下水中的NO-3-N,反应5h去除率为93%,经粉煤灰预处理后,反应4h,NO3--N去除率可达到98.6%。     

Study on polymorphisms of microsatellite DNA of six Chinese indigenous sheep and goat breeds

The genomes of six populations were screened using microsatellites as molecular markers, including Ujmuqin sheep, small-tailed Han sheep, Tan sheep, Hu sheep, Tong sheep and Yangtse River Delta (YRD) white goat. A total of seven microsatellite markers were used and genetic diversity and genetic distance were also determined. The results showed that there were 224 alleles in six populations, all seven loci showed polymorphism in all populations. The average heterozygosity of all populations was 0.949 9, and the mean polymorphism information content (PIC) of all six populations was 0.842 5–0.929 4. The six sheep (goat) popualtions were lowly differentiated with all loci, and the coefficient of phaenotype differentiation (Fst) was 2.6%, which was consistent with the coefficient of gene differentiation (Gst). The global heterozygote deficit across of all populations (Fit) amounted to 0.5%. The overall significant deficit of heterozygotes because of inbreeding within breeds (Fis) amounted to −2.2%. Two Unweighted Pair-group Method using Arithmetic Averages (UPGMA) dendrograms were constructed on the basis of Nei’s standard genetic distance (DS) and Nei’s genetic distance (DA) respectively. Hu sheep and Tong sheep were grouped at first, Ujmuqin sheep and small-tailed Han sheep clustered and then clustered with Tan sheep. Finally, Yangtse River Delta white goat joined in with all above. From this study, Ujmuqin sheep belongs to “Mongolia sheep” group, which corresponds with the historical records exactly. Ujmuqin sheep and small-tailed Han sheep, Tan sheep, Hu sheep and Tong sheep all vest in the “Mongolia sheep” group.     

聚醚类离子载体N95对山羊瘤胃代谢的影响

取来自于３头装有永久性瘤胃瘘管山羊的瘤胃液，在体外厌氧条件下以干草粉（占７５％）和混合精料粉（占２５％）为底物进行培养。在培养液中加入离子载体Ｎ９５，培养液中Ｎ９５质量浓度分别为０．２５、０．５０、１．００、２．５０和５．００ｍｇ·Ｌ－１。试验表明：Ｎ９５对培养液中ＴＶＦＡ（ｔｏｔｌｅｖｏｌａｔｉｌｅｆａｔｙａｃｉｄ）无明显影响，但显著降低了乙酸与丙酸的比例（从２．７０５降到１．５９４）以及培养液中氨氮（ＮＨ３－Ｎ）的质量浓度（从６９．０９下降到６１．０３ｍｇ·Ｌ－１，Ｎ９５使培养液中ＭＣＰ（Ｍｉｃｒｏｂｉａｌｃｒｕｄｅｐｒｏｔｅｉｎ）质量浓度从５５．６９上升到６５．６８ｍｇ·Ｌ－１（Ｐ＜０．０５），而使ＴＤＴＡ（ｔｏｔｌｅｄｅｈｙｄｒｏｇｅｎａｓｅ）质量浓度从３３６．５降至１５０．４μｇ·Ｌ－１（Ｐ＜０．０５）。结果显示了离子载体Ｎ９５改善了瘤胃发酵类型     

Sequential establishment of stripe patterns in an expanding cell population

Periodic stripe patterns are ubiquitous in living organisms, yet the underlying developmental processes are complex and difficult to disentangle. We describe a synthetic genetic circuit that couples cell density and motility. This system enabled programmed Escherichia coli cells to form periodic stripes of high and low cell densities sequentially and autonomously. Theoretical and experimental analyses reveal that the spatial structure arises from a recurrent aggregation process at the front of the continuously expanding cell population. The number of stripes formed could be tuned by modulating the basal expression of a single gene. The results establish motility control as a simple route to establishing recurrent structures without requiring an extrinsic pacemaker.     

相关序列扩增多态性(SRAP)一种新的分子标记技术

SRAP是一种新的DNA分子标记,具有简便、稳定、中等产率和容易得到选择条带序列的特点。SRAP是一种基于PCR技术的新的分子标记技术,其利用独特的引物设计对ORFs进行扩增,上游引物长17bp,对外显子进行特异扩增,下游引物长18bp,对内含子区域、启动子区域进行特异扩增,因个体不同以及物种的内含子、启动子与间隔长度不等而产生多态性。扩增产物用变性的聚丙烯酰胺凝胶分离,然后用放射自显影检测。本文在阐述SRAP的原理和流程后,详细论述了SRAP标记目前在植物遗传图谱构建、遗传多样性、基因定位、比较基因组学、杂种优势预测等方面的研究进展及应用前景。     

农业水费调整对农业节水的影响

针对我国农业节水与农业水费的现状 ,分析了二者之间的关系。从理论上阐述了调整农业水费对促进我国农业节水事业进一步发展的重要作用 ,并利用水利经济原理推算出有利于农业节水发展的节水水价。     

景观破碎带GPSRTK监测理论、技术方法及空间模型

由于自然或人为作用形成的景观破碎带不仅影响景观的观赏价值 ,还会引起水土流失和破坏生物多样性 .因此 ,对城乡景观破碎带的定量监测不仅有学术意义 ,更有应用价值 .该项目通过对各类景观破碎带的GPSRTK技术定量监测建立各类景观破碎带的空间分布数学模型 ,并精确监测其地图 (投影 )面积、临空面积、土方体积及其变动 ,为治理景观破碎带提供基础信息 .     

茶树与土壤中铅的存在形态与分布

茶树体内铅主要以草酸铅和磷酸氢铅、磷酸铅等难溶于水的磷酸盐的形态存在，其次为果胶酸铅、与蛋白质呈结合态或吸附态的铅，依次为水溶性有机酸铅和磷酸铅、硝酸铅和氯化铅为主的无机物及氨基酸铅。其中，在茶树的根、茎、叶中2种主要形态的铅含量分别为全铅量的97．34％、98．35％和99．65％。根细胞中的铅，主要分布在细胞壁和细胞核中，茎细胞中的铅主要分布在细胞核中，而叶片细胞中的铅主要分布在细胞质和细胞壁中。在未加入铅处理时，土壤中铅的存在形态及对应的铅含量大小顺序为硫化物残渣态〉碳酸盐结合态〉吸附态〉有机结合态〉交换态〉水溶性铅，加入外源铅后，变化顺序为硫化物残渣态〉交换态〉碳酸盐结合态〉有机结合态〉吸附态〉水溶性铅，硫化物残渣态和交换态的铅含量相对较高。     

Chromosome segregation errors as a cause of DNA damage and structural chromosome aberrations

Various types of chromosomal aberrations, including numerical (aneuploidy) and structural (e.g., translocations, deletions), are commonly found in human tumors and are linked to tumorigenesis. Aneuploidy is a direct consequence of chromosome segregation errors in mitosis, whereas structural aberrations are caused by improperly repaired DNA breaks. Here, we demonstrate that chromosome segregation errors can also result in structural chromosome aberrations. Chromosomes that missegregate are frequently damaged during cytokinesis, triggering a DNA double-strand break response in the respective daughter cells involving ATM, Chk2, and p53. We show that these double-strand breaks can lead to unbalanced translocations in the daughter cells. Our data show that segregation errors can cause translocations and provide insights into the role of whole-chromosome instability in tumorigenesis.