2007年第18届国际生物学奥林匹克竞赛(7)

问题46～48.下图示不同物质以不同方式通过生物膜。问题46.将图中的字母代号填到相应的空格内。(4分)运输机制     

肠道病毒71型研究进展

1概述肠道病毒71型(Human enterovirus 71,EV71)于1969年首次从美国加利福尼亚患有中枢神经系统疾病的婴儿粪便标本中分离出来[1],之后多次引起的世界性的暴发流行,尤其在欧洲和亚洲国家或     

高粱A_1型质核互作雄性不育性的遗传及建立恢复系基因型鉴别系可能性的商榷

通过研究发现,高粱A_1型质核互作雄性不育系与恢复系杂交的F_2,可育与不育的分离比有的组合呈3:1;另一些组合呈15:1。因此,我们认为不育系的基因型应是S(ms_1ms_1ms_2ms_2),其相应保持系的基因型应是F(ms_1ms_1ms_2ms-2),而恢复系的核内基因型则有(Ms_1Ms_1Ms_2Ms_2)、(Ms_1Ms_1ms_2ms_2)和(ms_1ms_1Ms_2Ms_2)等三种。从高梁的遗传、育种和品种资源研究出发,有必要将这三种恢复系的基因型予以区别。本文从理论上阐述了建立这种恢复系基因型鉴别系的可能性,和大家商榷。     

Entry into midgut epithelial cells is a key step in the selection of genotypes in a nucleopolyhedrovirus

An isolate of the Spodoptera frugiperda multiple nucleopolyhedrovirus comprises a stable proportion of deletion genotypes (e.g., SfNIC-C), that lack pif1 and pif2 rendering them noninfectious per os, and that survive by complementation with a complete genotype (SfNIC-B) in coinfected cells. To determine whether selection for particular ratios of complete and deletion genotypes occurs mainly during the establishment of the primary infection in insect midgut cells or during subsequent systemic infection, we examined genotype frequencies in insects that fed on OBs comprising different co-occluded mixtures of genotypes. Dramatic changes in genotype frequencies were observed between the OB inoculum and budded virus (BV) samples taken from larvae inoculated with OBs comprising 10% SfNIC-B + 90% SfNIC-C indicating that a marked reduction of SfNIC-C genotype had occurred in the insect midgut due to the immediate elimination of all OBs that originated from cells that had been infected only by SfNIC-C. In contrast, immediate changes were not observed in OBs comprising mixtures of 50% SfNIC-B + 50% SfNIC-C or those comprising 10% SfNIC-B + 90% SfNIC-C as most of the OBs in these mixtures originated from cells that had been infected by both genotypes. Subsequent changes in genotypic frequencies during five days of systemic infection were fairly small in magnitude for all genotypic mixtures. We conclude that the prevalence of defective genotypes in the SfNIC population is likely determined by a balance between host selection against OBs produced in cells infected by SfNIC-C alone and within-host selection for fast-replicating deletion genotypes. The strength of intra-host selection is likely modulated by changes in MOI during the infection period.     

怎样阅读微生物的基因型符号

怎样阅读微生物的基因型符号郑仲承（中国科学院上海生物化学研究所，上海２０００３１）关键词微生物，基因型符号微生物在生命科学研究中起着非常重要的作用，选用合适的微生物有时是取得良好实验结果的关键。在描述一个微生物的品系时，最重要的事就是区分它的基因型和...     

关于GSK公司的染色体组药理学战略采访Allen Roses 基因样本在全世界达到8万人添加信息提高竞争力

支撑GSK公司的开发流力线的，是拥有8万人样本的染色体组药理学（PGx）研究。利用添加了根据基因型选择患者的信息的“小型炸弹”来占领整个市场。[编者按]     

确定生物基因型的遗传学方法归纳

生物的表现型由基因型决定，而生物的基因型是无法通过肉眼分辨或物理、化学的方法鉴定的．它只能由一定的遗传学方法加以分析，其分析内容主要包括基因的载体是常染色体还是X染色体，相应性状的显隐情况等等。