人工雄性不育基因及恢复基因表达载体的构建

结合Cre／loxp定位重组系统和杂种一代的育种特点,构建了雄性不育基因表达载体pCABARTABn和相应的恢复基因表达载体pBINPLUSCre。将位于质粒pTTABn中的雄性不育基因表达盒(含TA29启动子、barnase基因及Nos终止子)切下插入中间克隆载体pGloxp2个同向lox位点之间,再将上述表达盒连同lox位．占、切下插入pCAMBar,获得以除草剂Basta为筛选剂的雄性不育基因表达载体pCABARTABn。PCR方法从溶原菌BM25．8基因组DNA扩增出Cre基因,克隆测序验证无误后插入PBI 525 CaMV 35 S-35S双启动子和Nos终止子之间,再将表达盒切下插入pBINPLUS质粒相应位点,得到恢复基因植物表达载体pBINPLUSCre。     

番茄早熟新品种──“农大早红”的选育

“农大早红”是以早粉２号作母本，沈农２号作父本，通过有性杂交、基因重组，优良性状互补，育成的高产、优质番茄早熟新品种。该品种植株长势中等，第１花序着生第６至第７位，花序间隔１～２片叶，三穗果封顶，属矮自封顶类型．耐寒力较强，座果率高，物候期早，果实发育快，定植后５２ｄ始收，比双亲提早４～６ｄ，前期产量超标２２．８％，总产量超标２６．９％果实近园形，红色，平均单果重１１９．２ｇ，果实酸甜适度，风味好，果皮略厚，不裂果，可溶性固形物含量４．５％～５％．适于日光温室，大、中、小棚覆盖和露地早熟栽培，单干整枝，９株／ｍ￣２以上，常年产量为５．２～６．０ｋｇ／ｍ￣２．     

RNA病毒的重组机制及其研究进展

RNA重组是RNA病毒普遍存在的变异方式之一,但仍有很多关键性问题尚未阐释清楚。目前认为重组机制主要有两种,复制型重组机制即模板转换（template-switch）,又称为copy-choice机制;另一种为非复制型重组机制,即断裂连接机制（breakage-religation）和类似于剪接的反酯作用（splicing-like transesterification）机制。由于重组在病毒进化变异过程中发挥着不同的作用,阐明重组机制有助于研究病毒进化变异和复制转录等生命周期过程。本文拟就RNA重组类型、重组机制、对RNA病毒重组的研究、重组的生物学意义及应用4个方面,综述RNA病毒重组机制及其研究进展。     

咖啡色水貂的培育

利用引进的黑十字水貂中偶然发现的 1只咖啡色十字公貂 ,运用毛色遗传规律 ,经过精心选配、繁育 ,成功地分离、重组了 1 2 0余只双隐性基因型纯合的咖啡色水貂 (bbss)。同时建立起一批具有重要育种价值的携带咖啡色基因的咖啡十字水貂 (杂合型bbSs,纯合型bb SS) ;携带咖啡色基因的黑十字水貂 (BbSS)基础兽群。本文阐述了繁育咖啡色水貂所采用的 7种选配方案。     

Different recombination frequencies in wheat doubled haploid populations obtained through maize pollination and anther culture

This study compared the meiotic recombination frequency between wheat doubled haploid (DH) populations obtained through two different methods, maize pollination (MP♀) and anther culture (AC♂). The comparison was based on a genetic linkage analysis, performed with DNA markers. Thirty-five polymorphic markers (15 SSR, 15 AFLP, 5 RAPD) were screened in MP♀ and AC♂ doubled haploids populations, derived from the same hybrid genotype (F₁ of ‘Eta’ × ‘Darkhan 15’). Nine linkage groups, comprising 35 loci (the MP♀ lines) and 31 loci (the AC♂ lines), were constructed. The linkage groups in both DH populations showed identical orders of markers, except for one group mapping to chromosome 6B. The MP♀ and AC♂ linkage maps differed significantly in recombination frequencies for corresponding intervals. In total, the AC♂ linkage map (495.5 cM) was 40.5% longer than the MP♀ map (352.8 cM), indicating a significantly higher meiotic recombination rate in pollen mother cells. The enhancement in recombination was visible in five of nine linkage groups, and in 7 intervals between individual loci out of 19 compared. Moreover, for 6 other intervals a lack of linkage was observed in the AC♂ population, as compared to the MP♀ map.     

AFLP analysis of genetic diversity in populations of <Emphasis Type="Italic">Botrytis elliptica</Emphasis> and <Emphasis Type="Italic">Botrytis tulipae</Emphasis> from the Netherlands

The objective of this study was to assess the genetic diversity and to infer the mode of reproduction of Botrytis elliptica and B. tulipae in the Netherlands. First, three molecular typing methods were compared for their ability to differentiate isolates of B. tulipae, B. elliptica, and B. cinerea. The methods compared were multilocus sequencing, restriction analysis of the ribosomal intergenic spacer (IGS) region, and amplified fragment length polymorphism (AFLP) analysis. AFLP fingerprinting provided the most efficient method to differentiate isolates within each Botrytis species and therefore this method was used for population analyses of B. elliptica and B. tulipae. Isolates of both species were sampled during successive growing seasons in experimental field plots in Lisse and other locations in the Netherlands. Among 174 B. elliptica isolates, 105 genotypes could be discriminated and 87 genotypes were found only once, reflecting high genotypic variation. Clonal genotypes were found only within growing seasons and in one location. Linkage disequilibrium analyses indicated that between 9.4% and 19.3% of the loci in clone-corrected samples were linked. The multilocus association index provided no evidence for random mating. We conclude that sexual recombination occurs in the B. elliptica population. Among the 170 B. tulipae isolates, 25 genotypes could be discriminated and four genotypes were found only once, reflecting a low genotypic variation. Clonal genotypes were frequently found in different growing seasons and different locations. Linkage disequilibrium analyses indicated that between 25.2% and 48.6% of the loci in clone-corrected samples were linked. We conclude that the B. tulipae population is mainly clonal with some recombination.     

白灵侧耳交配型遗传研究

控制白灵侧耳（Pleurotus nebrodensis）担孢子单核体交配行为的交配系统由A、B两个互不连锁的因子组成.在白灵侧耳的有性生殖过程中,除可按孟德尔定律产生标准的四种交配型的担孢子外,构成B因子的遗传单位还可以发生因子内的遗传重组,产生两种新的、不同于亲本的B因子,重组率为14.1%.未发现重组型A因子.     

添加前缀对重组蛋白生物学特性影响的预测分析

利用分子生物学软件DNASTAR对DAB389-αMSH和含有亲和标记、Xa factor识别序列、连接肽的DAB389（Gly4Ser）2-αMSH的表位、亲水性、等电点等生物学特性进行了预测分析。结果显示：DAB389（Gly4Ser）2-αMSH的表位为0.8,DAB389-αMSH为2.1;亲水性为2.7,高于DAB389-αMSH的1.96;两者的等电点均为5.9。His.Tag、Xa factor识别序列使重组蛋白的亲水性增强,表位降低;重组蛋白氨基端前70个氨基酸中不存在信号肽;DAB389（Gly4Ser）2-αMSH的表达量低于DAB389-αMSH2%左右,前缀对蛋白表达量有一定的影响。     

重组猪干扰素α的纯化工艺研究

[目的]研究重组猪干扰素α的纯化工艺,为进一步研究该蛋白的分子结构及rPoIFN-α标准品的制备奠定基础。[方法]将含重组菌E.coliBL21诱导表达后得到的粗制rPoIFN-α,分别用2种方案进行纯化。方案1,依次用GST亲和层析法、DEAE阴离子交换法及分子筛法层析三步法进行纯化;方案2,依次用GST亲和层析和分子筛法层析两步法进行纯化。纯化结果用SDS-PAGE及Western-blot进行纯度检测及鉴定。[结果]诱导表达后的表达产物经SDS-PAGE检测,发现在45Kd分子量处有目的条带,Western-blot检测有特异性条带。通过两步法纯化后的rPoIFN-α纯度达96%,蛋白得率为42.8%,三步纯化纯度为98.8%。[结论]两步法得到的蛋白纯度非常接近三步法,但与三步法相比工艺更为简单方便。