Study on the origin and taxonomic status of yak (Poephagus) using cytochrome b gene of mitochondrial DNA

There still exists a remarkable difference on the yak’s taxonomic status in Bovinae. Primers designed according to the mitochondrial gene sequences of Bos taurus reported were used to amplify and sequence the yak’s cytochrome b gene, and the whole sequence of cytochrome b gene was finally obtained. Using Ovis aries as outgroup taxa, the phylogeny about the representative species of Bovinae was analyzed. Results showed that among the different species, the ratio of transition/transversion (Ts/Tv) of Cytochrome b gene was 4.9, suggesting that the mutation was not saturation. The percentage nucleotide sequence divergence between yak and Bovinae was 8.0%–8.6%, which was higher than that of yak and Bison bison. Phylogeny analysis found that Poephagus grunniens and Poephagus mutus clustered first before gathering with Bison bison, indicating higher genetic comparability than that of Bos. The results sustained the idea that Poephagus grunniens and Poephagus mutus shared one ancestor—the primitive yak. The approximate divergence time between these two species was 0.55 million years. The data also supported the viewpoint that the yak is classified into Poephagus of Bovinae, including two species of Poephagus grunniens and Poephagus mutus. Translated from Acta Veterinaria et Zootechnica Sinica, 2006, 37(11): 1128–1123 [译自: 畜牧兽医学报]     

马铃薯种薯质量对生长和产量的影响Ⅰ .种薯大小

对影响马铃薯的几个主要因素及相互作用进行研究,结果表明,当播种密度一定时,种薯大小无一例外地显著影响产量,即种薯越大产量越高,而其他因素包括品种、来源、季节和海拔不同程度地影响生长和产量。播种时,单位面积的种薯出芽数调整为相同时,种薯大小对单位面积产量不产生影响。证明了种薯单位面积产生的主茎数对产量起决定性作用,特别是单株结薯较少的品种和秋冬作。     

高校如何从源头上预防和治理腐败

惩治和预防腐败教育是基础,制度是保障,监督是手段。高校反腐倡廉应从源头抓起,健全内容与形式相统一的预警机制,发挥纪检、监察、审计等职能部门的作用,建立群众监督网络,拓宽监督渠道,营造拒腐防变的氛围。     

关于蔓越桔种间起源关系的过氧化物酶同工酶研究

作者通过对过氧化物酶同工酶的研究,提出了大果蔓越桔(Vaccinium caycocus L.)和六倍体蔓越桔[V.hagerupii(L.& L.)Ahokas]起源于小果蔓越桔[V.microcatpus(Turcz)Hook]及小果蔓越桔和美国蔓越桔(V.macrocarpon Ait.)平行起源的假设。     

土壤起源与宜居地球的形成

在各种成土因素交互作用下,地球土壤起源和演变历经变化的环境和多种成土过程。研究表明最早的古风化壳出现在太古宙;而随着地球生物演进,生物因素加入风化成土作用与成土过程,土壤学家眼中的土壤形成、发育于寒武纪。漫长的地质历史时期不同的成土环境发育有各种类型土壤,这些土壤发育与演化过程又反作用于景观、地形、生态系统、气候系统,改变大气成分组成和地球化学循环,影响、反馈、调节全球或地区的表层系统,土壤圈的形成是宜居地球形成的重要标志。     

微波辅助萃取气质联用仪测定动物性食品中氯霉素残留量

运用微波辅助萃取技术,进行提取,结合气相色谱-质谱联用仪检测,建立动物性食品中氯霉素残留量的检测方法,该检测方法的回收率为76.2%-94.7%,相对标准偏差为6.1%-8.6%,最低检测浓度为0.1μg/kg。     

中华牛文化的起源、兴盛与时代变迁

中华牛文化源远流长,内涵丰富,这与汉民族早期的农耕生活、文化传统和认知心理有密切联系。但是,随着农耕文化的衰落,传统的牛文化也在迅速发生着时代变迁。本文简述了中国牛文化的起源 丰富多彩的中华牛文化与时代变迁。     

Molecular breeding for the BaMMV/BaYMV resistance gene ym4 in winter barley

The aim of this investigation was to develop a procedure for the largescale molecular breeding for ym4, allowing resistance to BaMMV/BaYMV to be fixed in early breeding generations of winter barley. A codominant STS marker derived from the restriction fragment length polymorphism marker MWG838 for the ym4 resistance gene was combined with a new and easy procedure for preparing leaf samples for polymerase chain reaction (PCR), theoretically allowing one person to extract DNA from 5000 samples in a single day. In the procedure for molecular breeding for ym4, all steps, including leaf sampling, DNA extraction, PCR amplification and digestion with restriction enzyme were assembled in microtitre plates allowing multipipetting throughout the procedure, including the loading of gels. The method is amenable to further automation with the aid of a robot arm. Double haploid (DH) lines, as well as F₂ and F₄ breeding lines were analysed and, based on markers, homozygous and heterozygous BaMMV/BaYMV resistant plants were identified for further breeding. The winter barley breeding programmes were modified to include marker-based selection for BaMMV/BaYMV resistance on DH or on F₂ individuals, which had been preselected for mildew and leaf rust resistance.     

关于‘白花山碧’桃亲缘关系的研究

该文对７０年代末发现并命名的‘白花山碧’桃进行了形态学分析、花粉扫描电镜观察、花粉败育现象分析与花粉母细胞减数分裂观察．研究发现,‘白花山碧’桃花粉严重败育,其花粉形态与‘白花’山桃（Ｐｒｕｎｕｓｄａｖｉｄｉａｎａｃｖ．Ａｌｂａ）和‘单白’桃相似．花粉母细胞减数分裂在１２月初至第二年２月中旬,其间有两次分裂高峰．根据上述研究结果及其它研究资料,提出‘白花山碧’桃与‘白花’山桃和‘单白’桃亲缘关系密切．     

细胞和病毒起源问题研究的进展

评价了有关生物起源的主要学说．提出代谢对生物分子,蛋白质对ＲＮＡ基因,细胞对病毒的同步起源假说,将各种观点综合为统一的细胞和病毒起源的进程．