一种基因工程改造的NADH高亲和力木糖还原酶突变基因可促进酿酒酵母发酵木糖生成乙醇

在导入表达毕赤酵母(Pichia stipitis)木糖还原酶(xylose reductase,XR)和木糖醇脱氢酶(xylitol dehydrogenase,XDH)基因的重组酿酒酵母中,木糖还原酶活性主要依赖辅酶NADPH,木糖醇脱氢酶活性依赖辅酶 NAD+,两者的辅助因子不同导致细胞内电子氧化还原的不平衡,是造成木糖醇积累,影响木糖代谢和乙醇产量的主要原因之一.将经过基因工程改造获得的NADH高亲和力的木糖还原酶突变基因m1,与毕赤酵母木糖醇脱氢酶(PsXDH)基因xyl2共转染酿酒酵母AH109,以转染毕赤酵母木糖还原酶(PsXR)基因xyl1和xyl2重组质粒的酵母细胞为对照菌株,在SC/-Leu/-Trp营养缺陷型培养基中进行筛选,获得的阳性转化子分别命名为AH-M-XDH和AH-XR-XDH.重组酵母在限制氧通气条件下对木糖和葡萄糖进行共发酵摇瓶培养,HPLC检测发酵底物的消耗和代谢产物的产出情况.结果显示,与对照菌株AH-XR-XDH相比,AH-M-XDH的木糖利用率明显提高,乙醇得率增加了16%,木糖醇产生下降了41.4%.结果证实,通过基因工程改造的木糖代谢关键酶,可用于酿酒酵母发酵木糖生产乙醇,其能通过改善酿酒酵母细胞内氧化还原失衡的问题,提高木糖利用率和乙醇产率.     

DNA损伤反应性蛋白参与中心体调控

中心体是动物细胞有丝分裂期微管组织中心,对于细胞有丝分裂期形成纺锤体、正常分裂及染色体精确分离至关重要. 中心体失调控常造成遗传物质错误分配,最终诱发肿瘤形成.因此,对中心体结构及数量的精密调控将对细胞命运起着决定 作用.目前发现,中心体至少包含100多种调节蛋白,这些蛋白在细胞内的功能各异.最近很多研究显示,多种DNA损伤修复及 应答通路的激酶或磷酸酶定位于中心体,并且参与中心体调控.本文将对中心体结构、中心体复制、中心体分离、中心体扩 增、DNA损伤与中心体异常及DNA损伤反应性蛋白在中心体调控中的功能作一综述.     

组蛋白乙酰化对成体干细胞生物学性状的影响

成体干细胞（adult stem cells,ASCs）是指存在于一种已经分化组织中的未分化细胞,它们可以再生修复损伤的组织和器官,是组织工程和细胞治疗的理想细胞。但是ASCs在体外扩增过程中容易发生自主分化和衰老,影响其在临床的广泛应用。组蛋白乙酰化作为表观遗传调节的重要机制,参与细胞分化、衰老及凋亡等众多细胞活动的调控。该文就组蛋白乙酰化对成体干细胞生物学性状的影响进行综述。     

Comparison of Influenza Outbreaks in the Republic of Kazakhstan and Russia Induced by 2009 Yearly New Variant of А(H1N1) Influenza Virus

The aim of the work is the comparison of the epidemiology of influenza and acute respiratory virus infections (ARVI) in the Republic of Kazakhstan with the corresponding influenza epidemic in Russia induced by influenza pandemic virus A/California/07/2009 in 2009.Data on influenza and ARVI from the Republic of Kazakhstan and Federal Center of influenza was collected and investigated over the course of several weeks from hospitalized patients with the same diagnosis among all population and in age groups on ...     

胡瓜钝绥螨对日光大棚茄子上烟粉虱的控制作用

为了评价胡瓜钝绥螨在我国日光大棚中对茄子上烟粉虱虱的控制作用。笔者研究了在24～34℃下胡瓜钝绥螨以烟粉为猎物时的发育历期,并在我国山东省寿光市的蔬菜基地上开展了利用胡瓜钝绥螨控制日光大棚茄子上烟粉虱的研究与应用。结果表明:胡瓜钝绥螨能够取食烟粉虱的卵、成虫、若虫及伪蛹;利用胡瓜钝绥螨能有效地控制烟粉虱成虫、卵、若虫种群数量的增长。根据胡瓜钝绥螨和烟粉虱的生物学特性,结合大棚茄子栽培过程中的环境条件,笔者提出了在日光大棚中应用胡瓜钝绥螨控制茄子上烟粉虱的策略:(1)在茄子的整个生长季节(250d)中需释放胡瓜钝绥螨4～6次,苗期每次每株释放5～10头,结果期每次每株释放20～40头;(2)释放胡瓜钝绥螨的生防区比常规化防区减少农药使用18次;(3)安装防虫网、适时释放胡瓜钝绥螨是生防成功之关键,生防区配合使用黄板效果更好。     

Detrimental effects of environmental tobacco smoke in relation to asthma severity

Background

Environmental tobacco smoke (ETS) has adverse effects on the health of asthmatics, however the harmful consequences of ETS in relation to asthma severity are unknown.

Methods

In a multicenter study of severe asthma, we assessed the impact of ETS exposure on morbidity, health care utilization and lung functions; and activity of systemic superoxide dismutase (SOD), a potential oxidative target of ETS that is negatively associated with asthma severity.

Findings

From 2002–2006, 654 asthmatics (non-severe 366, severe 288) were enrolled, among whom 109 non-severe and 67 severe asthmatics were routinely exposed to ETS as ascertained by history and validated by urine cotinine levels. ETS-exposure was associated with lower quality of life scores; greater rescue inhaler use; lower lung function; greater bronchodilator responsiveness; and greater risk for emergency room visits, hospitalization and intensive care unit admission. ETS-exposure was associated with lower levels of serum SOD activity, particularly in asthmatic women of African heritage.

Interpretation

ETS-exposure of asthmatic individuals is associated with worse lung function, higher acuity of exacerbations, more health care utilization, and greater bronchial hyperreactivity. The association of diminished systemic SOD activity to ETS exposure provides for the first time a specific oxidant mechanism by which ETS may adversely affect patients with asthma.     

Junker: An Intergenic Explorer for Bacterial Genomes

In the past few decades, scientists from all over the world have taken a keen interest in novel functional units such as small regulatory RNAs, small open reading frames, pseudogenes, transposons, integrase binding attB/attP sites, repeat elements within the bacterial intergenic regions (IGRs) and in the analysis of those junk regions for ge- nomic complexity. Here we have developed a web server, named Junker, to facilitate the in-depth analysis of IGRs for examining their length distribution, four-quadrant...     

Bacterial Phosphoproteomic Analysis Reveals the Correlation Between Protein Phosphorylation and Bacterial Pathogenicity

Increasing evidence shows that protein phosphorylation on serine, threonine and tyrosine residues is a major regulatory post-translational modification in the bacteria. This review focuses on the implications of bacterial phosphoproteome in bacterial pathogenicity and highlights recent development of methods in phosphoproteomics and the connectivity of the phosphorylation networks. Recent technical developments in the high accuracy mass spectrometry have dramatically transformed proteomics and made it possible the characterization of a few exhaus- tive site-specific bacterial phosphoproteomes. The high abundance of tyrosine phosphorylations in a few bacterial phosphoproteomes suggests their roles in the pathogenicity, especially in the case of pathogen-host interactions; the high abundance of multi-phosphorylation sites in bacterial phosphoprotein is a compensation of the relatively small phosphorylation size and an indicator of the delicate regulation of protein functions.     

聚乙二醇介导鹅掌楸悬浮细胞与CdSe／ZnS量子点纳米颗粒共孵育的互作特征

利用纳米材料介导的药物靶向治疗和动物细胞转基因等相关研究,日益受到人们的关注．但植物因存在细胞壁的障碍,无论原位还是离体细胞培养条件下,利用纳米技术进行基因转移均存在很大难度．因此设想,如通过纳米颗粒材料物理尺寸的改变和表面化学修饰,能改变纳米颗粒与植物细胞壁界面上的生物物理或生物化学特征,从而有利于纳米颗粒材料穿越植物细胞壁进入植物细胞,将对推动纳米技术在植物转基因领域中的应用产生重要意义．根据以上设想,研究了不同的共孵育时间和温度等条件下,杂交鹅掌楸的胚性悬浮细胞与经不同表面化学修饰的CdSe／ZnS纳米颗粒之间相互作用过程的细胞生物学特征,以及CdSe／ZnS量子点的细胞毒性．结果表明,在共孵育后3h以内,激光共聚焦显微镜和电子扫描显微镜下,均可观察到经表面后修饰带正电荷的CdSe／ZnS纳米颗粒．同时,胞吞进入细胞内部的表面携带正电荷的CdSe／ZnS纳米颗粒的量明显与共培养时间、温度有明显的依赖关系,表明它们可以通过细胞的液相胞吞作用进入杂交鹅掌楸细胞内,且不影响细胞的活性;而表面带负电荷的CdSe／ZnS纳米颗粒则主要聚集在细胞外壁附近．在培养溶液中添加20％（质量比）聚乙二醇,可进一步提高鹅掌楸细胞胞吞CdSe／ZnS纳米颗粒的量和减轻CdSe／ZnS纳米颗粒的细胞毒性．本研究表明,以表面携带正电荷的CdSe／ZnS量子点纳米材料作为基因载体,在植物悬浮细胞的转基因研究和应用中具有广泛的前景．