棉花种子特异性启动子的克隆及序列分析

启动子是基因表达的重要顺式调控元件,在基因工程中,种子特异性启动子可以调控外源基因在种子中特异表达,提高表达效率,增强转基因的效果。本试验根据棉花LEA蛋白D34基因序列设计引物,以海岛棉基因组DNA为模板,通过touch down PCR技术,获得D34基因的种子特异性启动子片段。测序结果表明该片段长1 384 bp,与已发表的D34基因序列相似度为94.87%。该片段除了含有启动子的基本元件TATA框、CAAT框外,还含有种子特异性启动子元件E-box、G-box、B-box、AACA基序等。此外,对其顺式元件做了生物学功能分析。     

Dactylospongia elegans—A Promising Drug Source: Metabolites,Bioactivities, Biosynthesis,Synthesis, and Structural-Activity Relationship

Marine environment has been identified as a huge reservoir of novel biometabolites that are beneficial for medical treatments, as well as improving human health and well-being. Sponges have been highlighted as one of the most interesting phyla as new metabolites producers. Dactylospongia elegans Thiele (Thorectidae) is a wealth pool of various classes of sesquiterpenes, including hydroquinones, quinones, and tetronic acid derivatives. These metabolites possessed a wide array of potent bioactivities such as antitumor, cytotoxicity, antibacterial, and anti-inflammatory. In the current work, the reported metabolites from D. elegans have been reviewed, including their bioactivities, biosynthesis, and synthesis, as well as the structural-activity relationship studies. Reviewing the reported studies revealed that these metabolites could contribute to new drug discovery, however, further mechanistic and in vivo studies of these metabolites are needed.     

对十八届三中全会《中共中央关于全面深化改革若干重大问题的决定》有关农村改革几个重大问题的解读

35年来,中国的农业农村发展在政策指引下取得了历史性跨越,当前的农村改革发展面临新情况、新矛盾.十八届三中全会《中共中央关于全面深化改革若干重大问题的决定》就推进农村改革发展作了重要战略部署,再次将农村改革推向新起点.文章从8个方面深入解读了有关农村改革的几个重大问题.     

油桃新品种‘红雨’

‘红雨’油桃是从‘中油桃9号’变异中选出的早熟黄肉新品种。果实近圆形;平均单果质量152g,最大达223g;果顶微凹,缝合线中深;果柄粗短,梗洼深广;完全成熟后果面80%以上鲜红,底色黄绿,果肉橙黄;硬溶质,肉质细脆,风味甜酸,可溶性固形物9.45%,去皮硬度9.46 kg·cm~(-2),粘核,不裂果;果实货架期较‘中油桃9号’长3~5 d。在砀山地区露地栽培,6月10日左右果实成熟,果实发育期约75 d。适合保护地栽培。     

基于改进新息序列的组合导航系统缓变故障检测方法

针对传统的残差χ~2检测法未充分考虑缓变故障渐进变化的特点,而导致对缓变故障检测失效的问题,提出了一种改进的新息序列故障检测方法。该算法在传统新息序列检测法的基础上,通过模糊隶属函数构造检验统计量函数,并利用加权平均算法将落在有故障和无故障概率密度曲线交迭区域的检验统计量纳入故障信息检验中,以增加判断缓变故障的信息,从而更早地检测到缓变故障,而又不会增加虚警。仿真实验结果表明,将该方法应用到联邦滤波组合导航系统中,能够有效提高农业机械组合导航系统对缓变故障的容错能力。     

桃芽变品种的RAPD分析

为了从遗传学基础上对9个桃品种进行分类及亲缘关系研究。利用随机扩增多态性DNA(RAPD)技术对其基因组DNA进行标记,并应用SPSS11.0软件进行聚类分析。聚类分析结果表明：不同桃品种在欧氏距离平方系数阈值为2.0~6.0时,聚为两大类,第一大类由‘满园红’、‘中油4号’、‘中油9号’和07-9-6组成,均为油桃;第二大类由97-6-83、NJC83、‘皖83’、NJC19和07-9-19组成,均为黄桃。在欧氏距离平方系数阈值为1.0~2.0时,所有品种聚为4类,‘NJC83’和其营养系变异97-6-83、‘皖83’聚为一类,NJC19和其变异07-9-19聚为一类,‘中油4号’和其营养系变异‘满园红’聚为一类,‘中油9号’和其变异09-6-9聚为一类。RAPD分析认为：母本与营养系变异间的遗传距离短,具有很近的亲缘关系,其在DNA水平上产生了一定量的变异性条带,出现了较大范围的变异。     

‘砀山酥梨’芽变‘97-05-9’的RAPD分析

利用RAPD分子标记技术对37份梨种质资源进行了遗传亲缘关系及分类研究。从80个随机引物中筛选出27个引物进行扩增,应用SPSS11.0软件进行聚类分析。聚类分析结果表明:不同梨品种之间存在明显的遗传差异,‘砀山酥梨’与营养系变异‘97-05-9’具有很近的亲缘关系,归为一类。且‘砀山酥梨’与其营养系变异‘97-05-9’有14个引物扩增出18条特异性条带,变异位点较多。     

Assessment of tolerance to NaCl salinity of five olive cultivars,based on growth characteristics and Na and Cl exclusion mechanisms

Changes caused by NaCl-induced salinity on several growth parameters and ions accumulation have been measured in five olive (Olea europaea L.) cultivars (‘Chemlali’, ‘Chetoui’, ‘Koroneiki’, ‘Arbequina I18’, and ‘Arbosana I43’) growing in a greenhouse in nutrient solution pot experiment. One-year-old plants were transplanted to sand–perlite (1:1) culture, and were irrigated with half-strength Hoagland nutrient solution containing NaCl at various levels (0.5, 50, 100 and 200 mM). Salinity induced significant decrease in growth parameters, but to a different extent in each cultivar. Leaf growth and total leaf area per plant were significantly affected by all salinity treatments in all studied cultivars, being ‘Arbequina I18’ the most sensitive cultivar. Leaf drop phenomenon was observed from 60 days after salt application at high salinity treatments, mainly in Arbequina I18. Contrary to leaf area, leaf thickness increased progressively during the experiment. ‘Chemlali’ developed thicker leaves at the two highest salinity treatments when compared to the other cultivars. Na⁺ and Cl⁻ concentrations were higher in roots than in shoots and leaves in most of the cultivars investigated. The effectiveness of Na⁺ exclusion mechanism in the roots differed significantly among studied cultivars, working effectively in ‘Chemlali’ (by inhibiting translocation of Na⁺ to the aerial part) and being much less efficient in ‘Arbequina I18’. Furthermore, leaf abscission can be considered as an additional tolerance mechanism of olive cultivars allowing the elimination of leaves that had accumulated Na⁺ and Cl⁻ ions. Tolerance to salinity stress was as follows: ‘Chemlali’ > ‘Chetoui’ > ‘Arbosana I43’ > ‘Koroneiki’ > ‘Arbequina I18’. This order of salt tolerance was indicated by lower reduction in plant growth parameters (shoot elongation, trunk diameter, total plant dry weight, internodes length, and total leaf area), the increase of leaf thickness, and by the effectiveness of the exclusion mechanism of Na⁺ and Cl⁻ in the root system.     

雌雄同体鱼类性别分化及性转变研究进展

在脊椎动物中,鱼类具有多样的性别分化方式,大致可分为雌雄异体、雌雄同体以及单性生殖3类.一般情况下,鱼类性别决定后,性腺可分化为卵巢或精巢,并且在整个生命周期内保持不变.而在雌雄同体鱼类,其性别可以从雌性转变为雄性、雄性转变为雌性或者在雌雄两种性别间进行多次转变.雌雄同体鱼类具有多种性别转变形式,是研究脊椎动物性别决定...     

基于机器学习的农用飞行器路径规划系统设计

基于作业空间模型及更新和飞行器机动性能约束,搭建了农用飞行器路径规划环境模型,并采用改进人工势能的机器学习算法,结合农用飞行器路径规划环境模型和障碍物检测模块,实现了农用飞行器路径规划的最优化。MatLab仿真结果表明:农用飞行器路径规划系统能够识别障碍物的位置和边界信息,并能快速制定出最优的飞行路径,指引农用飞行器顺利到达目标点。