白杨派杂种无性系生根特性研究

通过对采用杂交育种方法选育出的白杨无性系生根性状进行研究。结果表明,新无性系在最早生根时间、主侧根总数量、主侧根总长度等指标上均存在极显著差异,说明各无性系的生根能力具有显著差异。主根平均根数和侧根平均根数两个性状的遗传方差均大于环境方差,其重复力分别可达95％和87％。进一步分析结果表明易生根的无性系根原基数量最多,平均每段插穗约14．7～7．3个．而较难生根的无性系平均每段插穗约5．5～6．8个,难生根的毛白杨根原基数量最少,平均每段插穗约3．3个。通过层次分析法(AHP)对各无性系生根特性的综合评价结果表明：9606、9603、9608、9607、9614、9610、9602等7个无性系生根能力均优于其亲本和毛白杨。     

Expression and stability of amplified genes encoding 5-enolpyruvylshikimate-3-phosphate synthase in glyphosate-tolerant tobacco cells

Two distinct cDNAs for 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) were obtained from a glyphosate-tolerant tobacco cell line. The cDNAs were 89% identical and the predicted sequences of the mature proteins were greater than 83% identical with EPSPS proteins from other plants. Tobacco EPSPS proteins were more similar to those from tomato and petunia than Arabidopsis. One cDNA clone, EPSPS-1, represented a gene that was amplified in glyphosate-tolerant cells, while the gene for EPSPS-2 was unaltered in these cells. Consequently, EPSPS-1 mRNA was more abundant in tolerant than unselected cells, whereas EPSPS-2 mRNA was at relatively constant levels in these cell lines. Exposure of unselected cells and tobacco leaves to glyphosate produced a transient increase in EPSPS mRNA. However, glyphosate-tolerant cells containing amplified copies of EPSPS genes did not show a similar response following exposure to glyphosate. A significant proportion of the EPSPS gene amplification was maintained when tolerant cells were grown in the absence of glyphosate for eight months. Plants regenerated from these cells also contained amplified EPSPS genes.     

香蕉胁迫相关蛋白基因的克隆及其表达分析

通过随机克隆测序的方法从香蕉根系cDNA文库中获得胁迫相关蛋白基因,命名为MaSAP1(GenBank登录号为AGH14257.1)。扩增获得的cDNA序列与质粒OZ092的目的片段序列一致,表明MaSAP1是香蕉SAP基因编码框全长cDNA,包含一个510bp的最大开放阅读框,编码一个长169个氨基酸的蛋白质。蛋白质序列同源比对发现其含有完整的A20和AN1基序结构。系统进化树比对分析表明,MaSAP1与水稻和獐茅的亲缘关系较近。组织特异性研究表明,MaSAP1基因在香蕉根和果实中的表达量较高,在茎中的表达量最低。实时荧光定量PCR分析表明MaSAP1响应激素的处理,同时也响应干旱、低温、高盐和枯萎病菌的侵染等胁迫。可见,MaSAP1基因在植物生长发育和植物响应逆境中具有重要作用。     

Molecular typing of Bacillus thuringiensis serovars by RAPD-PCR

One hundred and twenty-six strains of Bacillus thuringiensis representing 57 serovars were allocated to 58 genomic types using random amplified polymorphic DNA (RAPD)-PCR patterns. Serovars darmstadiensis, israelensis, kenyae, kumamotoensis, kurstaki, morrisoni, pakistani, sotto, thuringiensis and tolworthi each encompassed identical or closely related strains. Despite this genomic homogeneity, most of these serovars also included at least one variant strain. Serovars aizawai, canadensis, entomocidus and sotto biotype dendrolimus, on the other hand, were genomically heterogeneous. Of the 57 serovars examined, 31 contained at least one strain with a closely related or identical RAPD pattern to a strain from a different serovar. We conclude that while the species is genomically diverse, the homogeneous serovars represent clonal lineages of successful insect pathogens.     

大头蛙Sox基因的克隆与序列分析

参考人SRY基因HMC—box的保守区序列,设计一对特异引物,采用PCR技术扩增了大头蛙的Sox基因,并对扩增产物进行了克隆与测序。结果在雌雄个体中均扩增出217bp的基因片段,与人对照相同。序列分析表明,大头蛙雌雄个体之间Sox序列没有差异,与人SOX基因的同源性达到88％,与其它各类动物的Sox基因也都有非常高的相似性。结果支持Sox基因在进化上十分保守的结论。     

Glutamate Dehydrogenase Activity Is Markedly Higher in a "Golgi-Bergmann"-Like Glial Clone than in Other Astroglial Cell Lines

Glutamate appears to be the neurotransmitter of granule cells, the major neuronal population of the cerebellar cortex. To determine the role of astroglial cells in the synthesis of glutamate, we have measured the specific activity of glutamate dehydrogenase (GDH) in clonal cell lines that might be the in vitro equivalents of the different cerebellum astroglial cell types. In conditions where GDH operates in the direction of glutamate synthesis, the specific activity of GDH measured in the "Golgi-Bergmann"-like clone was 4-6 times higher than in the "velate protoplasmic"- or "fibrous-like" astrocytic clones. These data correlate well with the intense immunoreactivity to GDH in Golgi-Bergmann astrocytes in vivo that has been recently reported.     

钛合金和钴铬合金表面白色念珠菌粘附的研究

目的比较钛合金(Ti-6Al-4V)和钴铬合金(Chromium-Cobaltalloy)表面白色念珠菌粘附能力的大小,研究表面粗糙度与细菌粘附的关系。方法将不同表面粗糙度的钛合金和钴铬合金试件进行白色念珠菌体外粘附试验,采用菌落形成计数法测定试件表面的细菌粘附量。结果各钛合金试件组的细菌粘附量均少于相同表面粗糙度的钴铬合金试件组,两种金属试件表面的细菌粘附量均随表面粗糙度的增大而增加。结论钛合金较钴铬合金更能减少由白色念珠菌引起的义齿性口炎等并发症,同时修复体表面严格的研磨抛光也能有效减少这些并发症。     

Oral administration of antigen does not influence the proliferation and IFN-γ production of responsive CD8+ T cells but enables to establish T cell clones with different lymphokine production profile.

Feeding of a whole casein diet, which abolished the α_s1-casein-specific proliferation and IFN-γ productivity of CD⁴⁺ T cells, did not affect the proliferative response of CD8⁺ T cells with regard to the antigen dose response, cell dose response, kinetics of the proliferation and epitope specificity, as well as IFN-γ production. To assess the characteristics of the CD8⁺ T cells, we established α_s1-casein-specific CD8⁺ T cell clones from both casein-fed and control mice. The established clones produced different amount of IFN-γ and IL-10, and one clone derived from the casein-fed mice produced a remarkable amount of IL-10. The clones from casein-fed mice produced considerable amounts of TGF-β, while those from control mice produced only small amounts. The possible role of CD8⁺ T cells in oral tolerance is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Generation and characterization of an estrogen receptor alpha‐iCre knock‐in mouse

Two estrogen receptors, ESR1 and ESR2, are responsible for the classical actions of estrogens in mammalian species. They display different spatiotemporal expression patterns and nonoverlapping functions in various tissues and physiological conditions. In this study, a novel knock‐in mouse line that expresses codon‐improved Cre recombinase (iCre) under regulation of the natural Esr1 promoter (Esr1–iCre) was developed. Functional characterization of iCre expression by crossing them with reporter lines (ROSA26‐lacZ or Ai9‐RFP) showed that iCre is faithfully expressed in Esr1‐lineage cells. This novel transgenic mouse line will be a useful animal model for lineage‐tracing Esr1‐expressing cells, selective gene ablation in the Esr1‐lineage cells and for generating global Esr1 knockout mice.