危害新疆西瓜的一种线状病毒的研究

从新疆染病的西瓜分离到一种线状病毒,该病毒可经汁液传播侵染属于６个科的１７种草本植物;染病的西瓜、哈密瓜和西葫芦引起植株生长阻滞、叶片皱缩、褪绿、泡斑、黄花叶以至坏死等系统侵染症状;该病毒可经桃蚜以非持久性方式传播;该病毒的病毒粒子为长约７５０ｍｍ的线形病毒粒子,在染病组织中形成风轮状内含体,证明该病毒属于马铃薯Ｙ病毒组;染病组织粗汁液提纯病毒制备物在ＳＤＳ双向免疫扩散试验中与小西葫芦黄花叶病毒抗     

The climatic variations and development of yellow soil in Beibei since the Holocene epoch

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家蚕限性黄茧品种与白茧品种组配四元杂交种研究

用改良成对家蚕限性黄茧品种 (中黄 B× 0 2、中黄 4×日黄 1)与现行强健、丝质优的成对白茧品种 (932× 75 32、芙蓉×湘晖 ) ,按现行四元杂交种的组配方式组配成四元杂交种 ,并进行饲养试验。结果表明 ,在正常季节 ,由 1对限性黄茧品种 (中黄 B× 0 2 )与 1对白茧品种 (“932× 75 32”或“芙蓉×湘晖”)组配成的四元杂交种 (“932 .中黄 B× 75 32 .0 2”或“芙蓉 .中黄 B×湘晖 .0 2”)与 2对白茧品种组配的四元杂交种“932 .芙蓉×75 32 .湘晖” (对照 )相比较 ,虫蛹率相似 ,万头产茧量增加 2 .2 2 %～ 4.2 8% ,万头茧层量增加 1.2 1%～ 3.86 %。白茧的一茧丝长、解舒率与对照相似 ,黄茧的一茧丝长 10 0 0 m左右 ,比对照短 10 0 m左右 ,解舒率比白茧差 2 0 %～ 30 %。说明成对限性黄茧种与成对白茧种组配的四元杂交种 (简称“2限黄 2白四元杂交种”)的综合经济性状可达到或超过现行实用四元白茧品种 (932 .芙蓉× 75 32 .湘晖 )的水平。“2限黄 2白四元杂交种”的杂交原种 8种组合中 ,有 4种组合 (即“限性黄茧 .白茧”)是雌茧黄色 ,雄茧白色 ,良种繁殖过程中利用这一特点鉴别雌雄工效比现行白茧品种提高 5倍左右 ,比斑纹限性品种提高 3倍左右 ,雌雄鉴别的准确率为 10 0 %。     

大麦黄花叶病毒抗性突破株系的分子变异

通过大麦黄花叶病毒 (Ba YMV)抗性突破株系的核酸 RNA1全序列分析并与野生株系比较表明 ,抗性突破株系在病毒复制酶或转运蛋白区域 (6K2 )和核酸 RNA复制酶区域 (NIb)存在二个变异位点 .在这二个位点上抗性突破株系核酸分子编码的氨基酸分别为脯氨酸 (Pro)和苏氨酸 (Thr) ,而野生株系分别为缬氨酸(Val)和丙氨酸 (Ala) .对该两种酶蛋白质二级结构分析显示 ,氨基酸的变异可能导致了蛋白质的结构、功能与性质的改变 ,并且此种变异与抗 Ba YMV冬大麦中抗性基因 ym4的功能丧失有关 ,同时也说明了大麦品种田间致病性的差异与病毒核酸分子中的点突变关系密切 .     

Generation of transgenic wheat resistant to wheat yellow mosaic virus and identification of gene silence induced by virus infection

The plasmid containing the promoter Act1, the coat protein (cp) gene of wheat yellow mosaic virus (WYMV) and the selectable bar gene, was delivered via particle bombardment, directly into immature embryos of a wheat cultivars. PCR and PCR-RFLP were employed to screen the existence of the cp gene in T0 and T1 generations. Seeds from the positive T1 plants were sowed in fields heavily contaminated with WYMV to detect their resistance. In field trial of virus infection, one of the transgenic wheat lines, P8-T2, exhibited highly disease-resistance. Western blot and RT-PCR analysis showed that the expression level of cp gene in the resistant transgenic line was reduced greatly compared to those susceptible to WYMV infection. This provided evidence to presume that the resistance obtained by the transgenic wheat line was stimulated by the mechanism of the virus induced gene silencing.     

Malvastrum yellow vein virus,a new Begomovirus species associated with satellite DNA molecule

Virus isolate Y47 was obtained from Malvastrum coromandelianum showing yellow vein symptom in Honghe, Yunnan Province. The complete nudcotide sequence of DNA-A was determined, it contains 2731 nuclcotides,having typical genomic organiTation of a begomovirns, encoding 6ORFs with 2ORFs [AVI(CP) and AV2] in virionsense DNA and 40RFs (ACl-AC4) in complementary-sense DNA. Comparisons show that the total DNA-A of Y47 has the highest sequence identity (77%) with that of Okra yellow vein mosaic virus-[201] (AJ002451), while less than 76% identities are found when compared with other begomoviruses. The molecular data show that virus isolate Y47 is a distinct begomovirns species, for which the name Maivastrum yellow vein vorus is proposed. Satellite DNA molecule (Y47β) was found to be associated with Y47 using the primers (beta01 and beta02) specific for DNAβ Y47β consists of 1348 nuclcotides, with a functional ORF (CI) in complemen-tary-sense DNA.Y47β has 62%--67% sequence identity with DNAβ molecule associated with Cotton leaf curl Muitan virus or Cotton leaf curl Rajasthan virus, while lower than 46% sequence identities are found when compared with other reported DNA[~ molecules. Relationship dendrograms show that DNAβ molecules are co-evolved with their help begomoviruses.     

黄河砂与沙漠砂胶砂强度及微观机理

针对天然砂料日趋枯竭的问题,采用黄河砂和沙漠砂分别全部替代天然砂配置砂浆,通过扫描电镜(scanning electron microscope, SEM)、X-射线能量光谱(energy dispersive spectrometer, EDS)和背散射电子(back scatter electrons, BSE)及元素扫描微观表征手段并联合力学强度试验,从宏微观角度揭示两种砂浆强度发展机理。结果表明：沙漠砂体系中胶砂界面处的钙矾石(AFt)和水化硅酸钙(C-S-H)发育完善,养护前期大量层状Ca(OH)₂紧密堆积,强化了胶砂界面结构;沙漠砂砂浆中的Ca/Si随龄期增加1.64,黄河砂砂浆的钙硅比增加0.52,有效保证其强度稳定性;沙漠砂颗粒黏结性强,充分填充砂浆界面孔隙,优化了砂浆结构的密实性,从而提升了其力学强度。     

花尾胡椒鲷人工育苗技术的初步研究

１９９７,１９９８年４－７月在厦门集美进行了花尾胡椒鲷人工育苗技术的初步研究。选取网箱养殖的成熟亲鱼,采用ＬＲＨ－Ａ２,ＨＣＧ和ＤＯＭ进行人工催产并进行人工授精;以６０ｍ＾３的室内水泥池作育苗池,将受精卵置于育苗池中孵化,并进行鱼苗培育,后期培育移到海上网箱进行。     

浅谈不良工程地质洞段施工经验在引黄工程中的应用

通过对比分析"山西省万家寨引黄工程北干线1号隧洞前期准备工程Ⅰ标"工程遇到的各种不良工程地质洞段施工方案,从中得到了一些有益的施工经验:松散土质的土洞段在一次支护方式的选择上宜采用钢支撑配合喷混凝土的支护方式;水工隧洞的防渗和排水宜采用"堵""截""排"综合处理的措施进行治理。     

Obtained transgenic wheat expressing pac1 mediated by Agrobacterium is resistant against Barley yellow dwarf virus-GPV

In fission yeast （Schizosaccharomyces pombe）, pacl gene was cloned with 99.3% nucleotide sequence similarity with published pacl in GenBank. In pET-5α expression system, the expression product of cloned pacl in E. coil showed activity to degrade the double-strand RNA. Harboring the binary vector pBI121, which contains pacl gene, Agrobacterium tumefaciens strain LBA4404 was used to transform the wheat immature embryos precultured 7-10 d. After preregeneration, regeneration and selection culture stage, totally 41 G418 resistant plants were obtained, in which 25 lines were proved to integrate with transgene and express transgene normally by PCR, Dot blot, RT-PCR and ELISA detection. Antivirus test carried out on 25 positive lines with high dose of Barley yellow dwarf virus-GPV revealed that 12 lines had resistance to BVDV-GPV in low level, another 12 lines had resistance to BVDV- GPV in middle level, and 1 line showed resistance to BVDV-GPV in high level. However, both low and middle level of resistance plants showed no symptoms when infected by viruses at low dose, which suggested the dose-dependent effect of the resistance mediated by pacl to BYDV-GPV.