基于特征提取的飞机结冰严重程度识别

飞机结冰会影响飞机飞行的各项性能指标,严重威胁飞行安全,但是飞机的结冰信息难以全面获取,因此提出一种基于特征和支持向量机的飞机结冰严重状态分类的算法。获取多个结冰传感器的信息构成测量向量并提取其特征,采用主要飞行参数构造飞机结冰严重状态特征空间,并建立多个支持向量机进行飞机结冰状况分类。该方法建立测量向量与飞机结冰严重状态之间的联系,能对飞机空中结冰严重程度作出较好的识别。     

Intragenic vectors for gene transfer without foreign DNA

The intragenic vector system involves identifying functional equivalents of vector components from the genome of a specific crop species (or related species to which it can be hybridised) and using these DNA sequences to assemble vectors for transformation of that plant species. This system offers an attractive alternative to current genetic engineering strategies where vectors are based on DNA sequences that usually originate from bacteria. The construction of intragenic vectors enables the well-defined genetic improvement of plants with all transferred DNA originating from within the gene pool already available to plant breeders. In this manner genes can be introgressed into elite cultivars in a single step without linkage drag and without the incorporation of foreign DNA. The resulting plants are non-transgenic, although they are derived using the tools of molecular biology and plant transformation. The use of intragenic vectors for the transfer of genes from within the gene pools of crops may help to alleviate some of the major public concerns over the deployment of GM crops in agriculture, notably the ethical issue associated with the transfer of DNA across wide taxonomic boundaries. This paper reviews the progress toward the development and use of intragenic vectors and the implications of their use for the genetic improvement of crops. Dedicated to the late Hans Sandbrink for his enthusiasm in helping to develop intragenic vectors     

Evidence for phenotypic assortative mating for flower colour in periwinkle

Two experiments were conducted with periwinkle, Catharanthus roseus, to determine the extent of natural outcrossing. Three white-flowered, fully self-fertile, monogenic recessive mutants, namely, dwarf, wavy leaf margin and curved leaf were used, together with their parental white-flowered variety, ‘Nirmal’, and a normal pink-flowered variety, PS-1. The extent of total outcrossing ranged from 43.4 to 79.3% among mutants. Outcrossing between white × white-flowered plants ranged from 28.3 to 65.3% and was two to four times greater than that between white × pink-flowered plants in the three mutants. The extent of out-crossing between white × pink-flowered plants was similar “02.2-15.0%” in all mutants and also similar to that in the normal white-flowered variety,‘Nirmal’(00.4%), where white × white flower out-crossing could not be estimated. There were no large differences in the number of seeds per fruit, percentage fruit set and germination percentage of seeds obtained from self, white × white and white × pink flower crosses made in the glasshouse. There were also no significant differences in the number of flowers produced by the genotypes used in the study. The observed higher frequency of white × white flower matings compared with white × pink flower matings appeared to be due to the constancy of flower colour exhibited by the butterfly pollinators Pachliopta hector and Catopsilia pyranthae during their flower visits. Observations made on the occurrence of natural self-pollination revealed that automatic self-pollination did not occur in periwinkle.     

基于递归纹理特征消除的WorldView-2树种分类

利用遥感影像识别树种是一个尚未解决的科学难题,传统方法在高分辨率影像树种分类中存在着诸多不适宜问题。本文通过提取WorldView-2影像的纹理特征构造高维数据,利用递归特征消除降低数据维数,逐步解除最大似然分类的休斯现象,并将有代表性的纹理特征集合与光谱特征结合,对树种进行分类。结果显示:在递归消除8个纹理特征后,最大似然的休斯现象达到了很好的规避;在结合光谱特征后,分类的总体精度达到了86.39%,Kappa系数达到了0.8410,比基于光谱特征的总体精度和Kappa系数高12.32%和0.1436。研究表明,在高维数据中通过递归特征消除规避最大似然分类的休斯现象,充分结合影像纹理与光谱信息对树种分类可以取得更为理想的结果。      

大豆抗病相关基因SR1正反义植物表达载体的构建及遗传转化研究

实验构建了CaMV35S启动子控制下的大豆抗病相关基因SR1的正反义植物双元表达载体pBISR1( )和pBISR1(-).通过根癌农杆菌叶盘转化法,将正义和反义SR1基因导入烟草Ha-vana 425,经卡那霉素筛选,获得了抗性植株.经PCR和PCR-Southern印迹分析,证明抗性植株中整和了SR1基因,RT-PCR分析进一步表明正义和反义基因皆能转录为完整的mRNA,经疫霉根腐接种及抗病性鉴定表明,转反义基因株系和未转基因株系均轻微感病,而转正义基因株系始终没有出现感病症状.     

Bartonellae are Prevalent and Diverse in Costa Rican Bats and Bat Flies

Species in the bacterial genus, Bartonella, can cause disease in both humans and animals. Previous reports of Bartonella in bats and ectoparasitic bat flies suggest that bats could serve as mammalian hosts and bat flies as arthropod vectors. We compared the prevalence and genetic similarity of bartonellae in individual Costa Rican bats and their bat flies using molecular and sequencing methods targeting the citrate synthase gene (gltA). Bartonellae were more prevalent in bat flies than in bats, and genetic variants were sometimes, but not always, shared between bats and their bat flies. The detected bartonellae genetic variants were diverse, and some were similar to species known to cause disease in humans and other mammals. The high prevalence and sharing of bartonellae in bat flies and bats support a role for bat flies as a potential vector for Bartonella, while the genetic diversity and similarity to known species suggest that bartonellae could spill over into humans and animals sharing the landscape.     

酵母双杂交表达载体pGBKT7_NPR1与pGADT7_NPR1的构建及酵母菌的转化

NPR1是水杨酸介导的系统获得性抗性（SAR）途径中不可或缺的一个转录辅助因子。在SA诱导下,NPR1被转运至细胞核内并与一些转录因子结合,以启动下游基因的表达。本研究通过PCR扩增获得拟南芥中NPR1基因CDS序列,经过限制性内切酶酶切后在T4连接酶作用下分别克隆至pGBKT7与pGADT7酵母表达载体上,并成功将其转化至Gold酵母菌株中。为利用酵母双杂交筛选NPR1参与形成的转录复合体中其它可能存在的蛋白质并阐明其在植物防御信号传导途径中的互作模式奠定了基础。     

烟草马铃薯Y病毒病相关基因eIF4E的片段克隆及RNAi载体构建

以感病烟草品种为材料,提取总RNA,根据已报道的eIF4E基因cDNA的序列,在保守区域和差异区域分别设计特异性引物,采用RT-PCR克隆出eIF4E基因的目的片段。以中间载体pKANNIBAL和表达载体pART27为基础,构建成以CaMV35S启动子为驱动的含有“正向eIF4E目的片段-pdk intron-反向eIF4E目的片段”的RNAi烟草表达载体,构建的RNAi载体将抑制eIF4E基因表达,为了解其基因功能和烟草抗病毒育种打下基础。     

木薯淀粉分支酶基因双价块根特异性反义表达载体的构建

淀粉分支酶(starch branthing enzyme,SBE)是高等植物淀粉生物合成的关键酶之一,包括分支酶I(SBEI)和分支酶II(SBEII)两种类型,调控着支链淀粉的合成.利用DNA重组技术,将这两种分支酶反义基因片段构建在一个植物表达载体中,形成双价反义表达载体p1301-SBEII-Spo-SBEI,其中SBEI反义基因置于CaMV35S启动子之后,SBEI反义基因置于块根特异型启动子.Sporamin之后,两者具有各自的Nos终止子.通过反复冻融法,将双价表达载体转入农杆菌EHA105,并采用PCR技术对所构建的农杆菌工程菌株进行了鉴定分析.