棉花高频体细胞胚胎发生及再生体系建立

棉花的体细胞胚胎发生率低,限制了转基因棉花的发展。为了扩大可再生棉花的基因型,发展新疆优质棉花的特点,以新疆的主要栽培品种新陆早33为材料,以下胚轴为外植体,使用葡萄糖,麦芽糖作为主要碳源,用Phytagel固化,对不同激素的浓度组合和培养条件进行探索,对棉花胚性愈伤的诱导到体细胞胚胎的发生阶段进行优化,体细胞胚胎成熟以后进行萌发培养可以获得正常的植株。通过试验证明,有利于棉花的愈伤组织生长的激素浓度为KT 0.1 mg/L,2,4-D 0.1 mg/L,下胚轴的中部诱导愈伤形态最好。体细胞胚胎发生阶段以KT,IBA组合,以低盐培养基进行子叶胚的成苗,建立了再生体系。     

Structural analysis of the exopolysaccharide produced by <Emphasis Type=Italic>Streptococcus thermophilus</Emphasis> ST1 solely by NMR spectroscopy

The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT experiments. The EPS is composed of hexasaccharide repeating units with the following structure: → 3)[α-d-Glcp-(1 → 4)]-β-d-Galp-(1 → 4)-β-d-Glcp-(1 → 4)[β-d-Galf-(1 → 6)]-β-d-Glcp-(1 → 6)-β-d-Glcp-(1 →, in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined using translational diffusion experiments which resulted in M_w = 62 kDa, corresponding to 64 repeating units in the EPS.     

High Genetic Differentiation of Hippophae rhamnoides ssp. yunnanensis (Elaeagnaceae), a Plant Endemic to the Qinghai-Tibet Plateau

RAPD markers were used to detect genetic diversity and population genetic differentiation of Hippophae rhamnoides ssp. yunnanensis, a sea buckthorn endemic to the Qinghai-Tibet plateau. The genetic parameters of percentage of polymorphic bands (92.86%), Nei’s gene diversity (h, 0.255), and Shannon’s index (I, 0.397) indicated high genetic diversity in this subspecies. The subpopulation differentiation suggested that 45.9% of genetic variation was among populations. High genetic differentiation among populations was also detected using AMOVA (47.02%). The main factors responsible for high genetic differentiation are probably related to natural geographic barriers among populations, gene drift, and limited gene flow caused by restricted pollen flow and seed flow. A Mantel test indicated that geographic distances were significantly correlated with genetic distances. The UPGMA phenogram based on Nei’s unbiased genetic distances and the result of three-dimensional model plots performed by principal coordinate analysis also supported the correlation. Altitude, however, did not have any clear effect on genetic differentiation.     

农药诱导害虫再猖獗的研究

害虫再猖獗是化学防治的3个负效应之一。农药的使用剂量、次数、使用方式以及导致植物营养变化等因素都可能引发害虫再猖獗。文章重点论述产生害虫再猖獗的原因和研究现状,并讨论再猖獗的今后研究方向。期望在害虫综合治理中能对再猖獗问题引起足够的重视。     

引致蝉若虫地方病的蝉棒束孢种群遗传结构

采用ISSR分子标记技术对在3个不同地区引起蝉若虫地方病的蝉棒束孢种群遗传结构进行研究.结果表明: 3个地方病种群均表现出较高的遗传多样性,其中敬亭山种群的遗传多样性最高,石台种群最小.UPGMA聚类分析表明,不同地方病种群无优势性,均为多系的异质种群,遗传谱系与地理来源无关.敬亭山不同采集时间的菌株表现出明显的时间异质性.种群(亚种群)间的遗传分化系数G_st为0.2153,而基因流N_m为0.9110(N_m＜1), 暗示低水平的基因交流是种群内遗传变异的主要原因之一.因此,蝉棒束孢种群水平的高异质性和低优势性是维持蝉若虫地方病的遗传结构特征.     

中水技术污水处理工艺去除病毒的效果

中水技术开发既可缓解水资源的紧缺,又能改善城市环境。本文报道用石英粉吸附/洗脱和浓缩棒脱水的二步浓集水病毒技术(回收率为25.4～37.3％),研究中水技术不同处理工艺去除病毒的效果。结果,二级处理可去除掺入病毒的98.9％,结合三级处理的混凝沉淀和过滤,可去除99.976％,再加活性炭吸附或加氯消毒,所得中水分别去除掺入病毒的99.986％和99.991％。经首都机场中水道试验厂水样检测表明,中水中未检测到病毒(<0.23PFU/L)。     

葡萄SBP基因家族生物信息学分析

SBP(squamosa promoter binding protein,SBP)基因家族是植物所特有的一类重要转录因子,广泛参与植物生长、发育以及多种生理生化反应的信号传导。葡萄是继拟南芥、水稻和杨树之后完成全基因组测序的第四种开花植物,因此葡萄逐渐成为分子生物学研究的重点对象,进行葡萄基因组信息挖掘与分析对于葡萄功能基因组学的发展具有重要意义。本文利用生物信息学方法对葡萄家族45条SBP蛋白序列的系统发生和SBP基因组定位进行分析,然后对其氨基酸组成成分、理化性质以及二级和三级结构进行预测和分析,同时还分析了葡萄与拟南芥的SBP基因家族之间的联系。结果显示这45条蛋白序列与拟南芥16个SBP基因蛋白序列一起分成了3个亚族,说明拟南芥与葡萄SBP基因间具有较高的保守性;进一步的基因组定位结果发现其分布在14条染色体上,较拟南芥在染色体上的分布更为分散。研究还发现不同亚家族间氨基酸数目、氨基酸序列间的疏水性存在一定的差异;而二级结构预测结果发现,41条氨基酸序列以随机卷曲为主要组成部分,这与拟南芥相似,且45条氨基酸序列三维结构十分相似。本文实验结果均为葡萄SBP基因家族的进一步功能分析提供了重要研究基础。