亚麻遗传转化体系的建立及几丁质酶基因导入的研究

报道了亚麻遗传转化体系的建立和几丁质酶基因对亚麻遗传转化的研究。亚麻下胚轴切段培养在不同激素浓度的ＭＳ培养基上,诱导分化出不定芽。最佳的激素组合是ＭＳ＋ＢＡ１ｍｇ／Ｌ＋ＩＡＡ０．５ｍｇ／Ｌ,分化频率可达９７％。亚麻的下胚轴经带有几丁质 根癌农杆菌感染后,在含有１００ｍｇ／Ｌ卡那霉素的选择分化培养基上,１４￣２１ｄ就能产生抗生小芽,小芽进一步伸长后可在１００ｍｇ／Ｌ卡那霉素的ＭＳ选择生根培养基（ＭＳ     

种群动力学模型解的振动性和渐近性

本文考虑当环境的容纳量为单调或者振动时,单种群增长模型解的振动性和渐近性,所得定理推广了文献[5］中的结果．     

Next-generation sequencing to generate interactome datasets

Next-generation sequencing has not been applied to protein-protein interactome network mapping so far because the association between the members of each interacting pair would not be maintained in en masse sequencing. We describe a massively parallel interactome-mapping pipeline, Stitch-seq, that combines PCR stitching with next-generation sequencing and used it to generate a new human interactome dataset. Stitch-seq is applicable to various interaction assays and should help expand interactome network mapping.     

一类包虫病传播动力学模型的研究

研究了一类具有终宿主产卵期和中间宿主虫卵成熟期两时滞的包虫病传播动力学模型,得到了决定系统动力学行为的阈值R_0,当R_0〈1时,证明了未感染平衡点是局部渐近稳定的;当R_0〉1时,得到了感染平衡点是局部渐近稳定的充分条件。通过数值仿真验证了理论结果并探讨了时滞对系统动力学行为的影响,且发现若时滞在一定的范围内系统存在周期解.     

Clioquinol targets zinc to lysosomes in human cancer cells

A panel of 52 murine monoclonal antibodies was found to recognize antigenic determinants that had been conserved among all major genetic subgroups of the H5N1 avian influenza virus prevalent since 1997. We screened a phage display library for peptides recognized by one such antibody (8H5). We analysed the specificity of 8H5 for reactive peptides presented as fusion proteins of HBc (hepatitis B core protein) and HEV (hepatitis E virus) structural protein, p239. This was then related to the specificity of the native HA (haemagglutinin) molecule by virtue of the capacity of fusion proteins to compete for 8H5 binding with different strains of H5N1 virus and the reactivity of antisera generated against fusion proteins to bind native HA molecules, and to inhibit haemagglutination and arrest infection by the virus. Nine reactive peptides of different amino acid sequences were identified, six of which were also reactive with the antibody in association with HBc and four were in association with p239. Binding occurred with the dimeric form of the four p239-fusion proteins and one of the HBc-fusion proteins, but not with the monomeric form. The HBc-fusion proteins blocked 8H5 binding with four strains of H5N1 influenza virus. Mouse antisera generated against fusion proteins bound to HA molecules, but did not inhibit haemagglutination or arrest H5N1 infection. Our findings indicate that 8H5 recognizes discontinuous sites presented by secondary and possibly higher structural orders of the peptides in spatially favourable positions for binding with the antibody, and that the peptides partially mimic the native 8H5 epitopes on the H5N1 virus.     

基于社区发展的生物多样性保护策略——以浑善达克沙地生态恢复为例

生物多样性保护,必须考虑保护与发展这一对矛盾的合理解决,如果要同时满足保护和发展的要求,两者的利益都应考虑。基于社区发展的生物多样性保护(Community-basedconservation,CBC)策略就是在这一理念指导下应运而生的,它强调社区居民在保护行动中的主动参与,使他们的意见和利益能在土地利用决策中得到重视,在社区经济发展的基础上达到保护的目的。该模式在全球生物多样性保护中发挥了重要作用,但这种模式是多学科交叉的产物,其成功关键在于资源管理权力的转移,对有关问题进行了分析。在我国浑善达克沙地退化生境恢复和生物多样性保护实践中,采用CBC模式,通过政府、科学家以及社区居民共同参与,对当地自然条件和社会经济基础综合分析,使大面积的退化沙地草地得以恢复。具体地,在有水分、电力、肥料、交通等有保证的土地上进行高效集约化利用,腾出大量退化土地进行封育,借助自然力恢复受损的生境。同时积极建设生态小城镇,提高社区居民的生活水平,使生物多样性得到保护和草地资源得到可持续利用,在环境改善的同时促进了经济发展。     

长野芽孢杆菌普鲁兰酶基因在枯草芽孢杆菌中的表达及酶学性质研究

根据NCBI上报道的基因序列设计引物,以长野芽孢杆菌(Bacillus naganoensis)ATCC53909的染色体DNA为模板,PCR扩增普鲁兰酶编码基因pulB。将此基因与表达载体pWB980连接构建重组质粒pWB-pulB,并转化枯草芽孢杆菌WB600。SDS-PAGE结果显示,在100 kD处有特异性条带,经测定重组转化子粗酶液酶活力达10.94 U/mL。酶学性质分析表明,其最适反应温度为60℃,最适反应pH为5.0,且在温度30-60℃及pH4.0-6.0范围内稳定,适合淀粉加工行业的应用。     

Pyrazolo[3,4-d]pyrimidine derivatives containing a Schiff base moiety as potential antiviral agents

A series of pyrazolo[3,4-d]pyrimidine derivatives containing a Schiff base moiety were synthesized, characterised, and evaluated for their activity against tobacco mosaic virus (TMV). Biological assays indicated that several of the derivatives exhibited significant activity against TMV. In particularly, compounds 5y and 5aa displayed excellent inactivating activity against TMV, with half maximal effective concentration (EC₅₀) values of 70.3 and 53.65?μg/mL, respectively, which were much better than that of ribavirin (150.45?μg/mL), and 5aa was superior to ningnanmycin (EC₅₀?=?55.35?μg/mL). Interactions of compounds 5y and 5aa with TMV coat protein (TMV-CP) were investigated using microscale thermophoresis and molecular docking. Compounds 5y and 5aa displayed strong binding capability to TMV-CP with dissociation constant (K_d) values of 22.6 and 9.8?μM, respectively. These findings indicate that pyrazolo[3,4-d]pyrimidine derivatives containing a Schiff base may be potential antiviral agents.     

Pretreatment efficiency and structural characterization of rice straw by an integrated process of dilute-acid and steam explosion for bioethanol production

The combined pretreatment of rice straw using dilute-acid and steam explosion followed by enzymatic hydrolysis was investigated and compared with acid-catalyzed steam explosion pretreatment. In addition to measuring the chemical composition, including glucan, xylan and lignin content, changes in rice straw features after pretreatment were investigated in terms of the straw's physical properties. These properties included crystallinity, surface area, mean particle size and scanning electron microscopy imagery. The effect of acid concentration on the acid-catalyzed steam explosion was studied in a range between 1% and 15% acid at 180°C for 2 min. We also investigated the influence of the residence time of the steam explosion in the combined pretreatment and the optimum conditions for the dilute-acid hydrolysis step in order to develop an integrated process for the dilute-acid and steam explosion. The optimum operational conditions for the first dilute-acid hydrolysis step were determined to be 165°C for 2 min with 2% H(2)SO(4) and for the second steam explosion step was to be carried out at 180°C for 20 min; this gave the most favorable combination in terms of an integrated process. We found that rice straw pretreated by the dilute-acid/steam explosions had a higher xylose yield, a lower level of inhibitor in the hydrolysate and a greater degree of enzymatic hydrolysis; this resulted in a 1.5-fold increase in the overall sugar yield when compared to the acid-catalyzed steam explosion.     

大肠杆菌ptsHI-crr基因的敲除及其对苯丙氨酸生产的影响

L-苯丙氨酸(L-phenylalanine)是重要的食品和医药中间体。利用大肠杆菌发酵葡萄糖生产苯丙氨酸时,对葡萄糖转运起重要作用的磷酸烯醇丙酮酸糖磷酸转移酶系统(PTS)对苯丙氨酸产量有很大影响。由ptsHI-crr操纵子编码的磷酸组氨酸载体蛋白(HPr),酶I(EI)和酶IIAGlc是PTS的必要组分,通过敲除ptsHI-crr得到PTS缺陷菌株,可以使葡萄糖代谢更多地流向苯丙氨酸生物合成。采用Red同源重组技术将大肠杆菌染色体上的ptsHI-crr基因替换为四环素抗性基因,得到PTS缺陷菌株。该菌株在以葡萄糖为惟一碳源的培养基中摇瓶培养,菌密度为对照菌株的2.7倍,苯丙氨酸产量为对照菌株的6.3倍。