南农87C-38大豆优质11S球蛋白Gy7基因克隆及序列分析

大豆种子不仅富含蛋白质,而且赖氨酸含量较高,利用大豆高赖氨酸基因能够弥补谷类作物种子赖氨酸含量的不足.运用现代分子生物学技术,从高蛋白大豆南农87C-38中克隆11S球蛋白Gy7全基因及cDNA序列.经生物公司测序后,利用vector NTI软件将所克隆的Gy7全基因及cDNA序列与Genbank(AF319776和AF319777)报道的序列进行比对分析,同源性分别为99%和99.6%.序列比对结果显示,Gy7基因cDNA与Genbank报道的序列之间所有的核苷酸差异都位于第3外显子.由此推测,第1、第2和第4外显子编码的氨基酸对于G7多肽形成特定高级结构可能具有非常重要的作用,它们在进化过程中受到的选择压力可能比第3外显子更强.根据遗传密码表推测,克隆的Gy7与Genbank报道的cDNA序列所编码的多肽,两者存在2个氨基酸组成的差异.大豆球蛋白Gy7优质基因的获得为今后利用转基因技术改良水稻、小麦等谷类作物的营养品质奠定了基础.     

某SUV车内轰鸣声问题的解决

NVH性能是影响车辆舒适性的重要因素之一。对某SUV车型加速过程中当发动机转速为1 300 r/min和1 600 r/min时的轰鸣声问题进行排查研究,通过阶次分析、模态分析、工作变形分析,发现两个转速下的轰鸣声均是由车架局部模态引起。为此,通过采取在对应位置加装动力吸振器的措施,有效抑制车架局部模态,道路试验结果表明车内轰鸣声得到明显改善,主观评价可接受,车内噪声整体降低7 dB(A)左右。     

基于ANSYS Workbench的FSEC车架有限元分析

以华南农业大学FSEC方程式(Formula Student Electric China)赛车为对象,利用三维建模软件CATIA建立车架CAD模型,通过有限元分析软件ANSYS对其进行静态强度以及运动学模态分析,分析该车架在多种工况下的应力和扭转刚度及不同阶数的固有频率和振型,验证了该车架设计的合理性,从而确保赛车能够安全参赛。     

Hybridization of Sinapis alba L. and Brassica napus L. via Embryo Rescue

Embryo rescue techniques were used to obtain hybrids between Sinapis alba L. (white mustard) and Brassica napus L. (oilseed rape) with the goal of improving the disease tolerance of oilseed rape. Hybrid plants with 31 or 43 chromosomes were only recovered, when S. alba, was used as the female parent. One hybrid was obtained from the cross S. alba L. cv. ‘Kirby’×B. napus L. cv. ‘Topas’, while 26 hybrids were obtained, when various S. alba L. cultivars were pollinated with the rapid cycling B. napus line CrGC 5006. All F₁, hybrid plants were male sterile; however, the first generation backcross to B. napus L., also obtained by embryo rescue, produced plants with 50 chromosomes and 61–84 % pollen viability. Second backcross generation seed was produced by normal sexual crossing. Preliminary cytological analyses of pollen mother cells of hybrid plants suggests the possibility of genetic exchange between the two species.     

Classification of a world collection of white clover cultivars

Summary Morphology, flowering, cyanogenesis and leaf markings of 109 white clover (Trifolium repens L.) cultivars, grown as spaced plants and in small plots, were measured. Principal component analysis and cluster analysis were used to compare cultivars. Cultivars were classified into four broad groups. The most important criteria for distinguishing between groups were leaf size, cyanogenesis and combinations of these. Group I, termed small, included small-leaved, prostrate cultivars; Group II, termed intermediate, included the majority of the cultivars which were characterised by medium sized leaves and relatively low cyanogenesis levels; Group III, termed large, included the large-leaved highly cyanogenic cultivars; and Group IV, termed ladino, included large-leaved acyanogenic cultivars.     

火鸡传染性法氏囊病病毒YL株VP2基因的克隆和序列比较

参考GenBank发表的传染性法氏囊病毒(IBDV)基因组序列,设计并合成了一对特异扩增IB-DVVP2基因的引物。以广西玉林发病火鸡群分离的IBDV野毒YL株为材料,以其基因组为模板利用RT-PCR技术扩增出了1.5kb的cDNA产物,将VP2基因克隆于PUC119质粒上,得到重组PUC119质粒。并对VP2基因全序列测定、分析和聚类表明,YL株与欧洲超强毒株非常相似,而与经典强毒株、弱毒株和变异株相差较大。     

Evaluation of an Indian germplasm collection of the medicinal plant Bacopa monnieri (L.) Pennell by use of multivariate approaches

Twenty seven accessions of Bacopa monnieri collected from semi-temperate, subtropical and tropical environments at geographically distinct locations in India were examined for genetic variability carried in them at Lucknow, India in a semi-temperate environment. The accessions were grown in earthen pans, arranged in completely random block design, replicated four times, and observed for 13 qualitative and 24 quantitative characters, including bacoside-A content of herbage. On the basis of principal component and canonical variable analyses, the accessions could be grouped into seven clusters, of 2 to 6 accession sizes. The metroglyph analysis using five qualitative traits, cluster analysis and dendrogram drawn using D² data separated the clusters IV and V and cluster VII from all the others. The bacoside-A content of the herbage was found to be usually low in clusters of accessions possessing vigorous vegetative growth such as in cluster VII. It was also observed that some of the clusters included accessions having wide geographical origins. It was inferred that both the gross agroclimatic environment of a region and microenvironment in the vicinity of water bodies where a Bacopa monnieri genotype occurred must have interacted for the natural selection of the concerned genotype. This revised version was published online in July 2006 with corrections to the Cover Date.     

Modal Analysis and Vibration Control of Benfield Frame

There is a low frequency and great amplitude on Benfield frame of Jianfeng chemical plant. With finite element modal, the reasons and mechanism of the vibration on Benfield frame are analyzed and confirmed. And a method of vibration control about the main vibration resource (100V10) is proposed to reduce the amplitude of Benfield frame vibration.     

不同材质仿生凸齿镇压器滚动件的模态分析

为了探讨由不同材质组成的仿生凸齿滚动件,在镇压作业时对脱土和土壤表面微形貌加工性能的影响,利用Autodesk Algor Simulation软件,对铸铁材料和UHMWPE—铸铁组合材料仿生结构滚动部件进行了模态分析。取前8阶模态,对2种滚动部件的固有频率和最大振幅做出对比,并考察滚动部件不同位置处的振幅。结果表明,UHMWPE—铸铁组合材料滚动部件在前8阶模态下各阶模态的最大振幅均大于铸铁材料滚动部件,增幅为5.716～30.077mm;UHMWPE—铸铁组合材料滚动部件更容易在相对较低的频率下获得更大振幅;在靠近辐板圈中部,即传递到牵引机构件处,UHMWPE—铸铁材料滚动部件平均振幅比铸铁材料滚动部件小0.213mm。由此可得出以下结论:相对于铸铁材料滚动部件,UHMWPE—铸铁组合材料滚动部件可在更好地保证牵引稳定性的前提下,在镇压作业时,能增强其仿生凸齿尖端处的脱土潜力,并保障对土壤表面所加工微形貌的强度。这为仿生凸齿镇压器材料的选择、牵引装置行驶速度的设定以及滚动部件上激励装置的设置提供了参考。