一类种群进食速度与时间有关的排序问题

本文考虑了工件的加工速度随交货期的接近不断加快的排序模型,给出了初始速度不为零情况下最小化加工时间的最优算法.并讨论了不完全信息情形下工件的最大延迟比该模型的研究结果可应用在种群对食物的最优收寻问题中.     

大豆种子萌发过程中的差异蛋白质组研究

运用蛋白质组学技术对大豆(Glycinemax)N2899种子萌发0h、8h、36h、60h4个时期蛋白质的差异表达情况进行了研究.结果发现,在考马斯亮蓝染色的双向电泳pH3～10胶上,PDQuest图像分析软件可识别的点约350个,其中表达量变化2.5倍以上的蛋白质点有24个,而绝大部分大豆种子贮藏蛋白在萌发期尚未降解.在萌发的第一阶段,24个差异表达蛋白中有10个蛋白质的丰度发生变化.第二阶段,差异表达蛋白的种类和量增加,其中15个蛋白质是动态变化的,14个蛋白质在胚根突破种皮时表达量达到峰值,表明吸胀后种子内的生命活动越来越强.对这24个蛋白质点进行胶内酶解,用基质辅助激光解析电离飞行时间质谱测定均获得肽质量指纹图谱.搜索大豆的UniGene库初步鉴定出6个蛋白质,分别是核苷二磷酸激酶、热激蛋白、硫氧还蛋白、35ku种子成熟蛋白及种子成熟蛋白PM36.对这些蛋白质在种子萌发过程中可能的作用进行了讨论.     

Isolation and characterization of a SEP- like gene from <Emphasis Type="Italic">Alpinia hainanensis</Emphasis> (Zingiberaceae)

A cDNA clone, AhSEP3 was isolated from the young inflorescences of Alpinia hainanensis. AhSEP3 cDNA is 891 bp long with an open reading frame of 726 bp that encodes a 241-amino acid protein. Sequence comparisons showed that AhSEP3 is very similar to SEP3 homologues. Phylogenetic analyses indicated that AHSEP3 is a new member of AGL2 subfamily. In situ hybridization analyses showed the expression pattern of the AhSEP3 is very similar to those of SEP3 and SEP3 homologs in other plant species, i.e. the signals of AhSEP3 are present in the inner three whorl of the floral organ.     

Denaturing gradient gel electrophoresis analysis with different primers of subgingival bacterial communities under mechanical debridement

DGGE of 16S rDNA is one of the most frequently used methods to study microbial communities. In this study, the DGGE profiles of different 16S rDNA regions of the periodontal pathogens Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella nigrescens were investigated. The results suggested that V3-V5 and V6-V8 fragments may be suitable for community analysis of subgingival bacteria. Further analysis of subgingival samples with V3-V5 and V6-V8 regions as target fragments suggested that, in chronic periodontitis, re-colonization by periodontal bacteria with a population very similar to the baseline may occur by 6 weeks after mechanical debridement.     

木酮糖激酶基因整合表达载体构建及在酿酒酵母中的过表达

【目的】以载体p406ADH1为构建骨架,构建一个酿酒酵母(Saccharomyces cerevisiae)工业菌株的整合表达载体。【方法】通过酶切连接的方式,将4个元件片段:作为筛选标记的G418抗性基因KanR,用于基因表达的ADH1终止子片段,酿酒酵母W5自身木酮糖激酶基因,18S rDNA介导的同源整合区,插入到骨架质粒p406ADH1中,得到多拷贝整合表达载体pCXS-RKTr。将该载体线性转化酿酒酵母后,对转化子中木酮糖激酶酶活进行测定,检测其表达情况。【结果】重组质粒在酿酒酵母体内实现了木酮糖激酶的高水平稳定表达,其酶活力是初始菌株的2.87倍。【结论】本实验构建了一个酿酒酵母工业菌株整合表达载体,并用此载体过表达了其自身的木酮糖激酶基因。该重组质粒载体的构建可以有效解决酿酒酵母中自身木酮糖激酶酶活较低的情况,这为利用木糖高产乙醇酿酒酵母基因工程菌株的构建和其它酵母重组质粒载体的构建奠定基础。     

大豆体细胞胚系培养及其微卫星DNA稳定性研究(简报)

植物离体培养是植物基因操作中的重要一环,也是植物个体发育研究中基因表达研究的有益参考体系。在继代培养过程中发生的遗传变异有时会使再生植株丧失优良的性状而需加以控制和避免。为此,首先需要了解培养过程中的遗传变异情况。     

穴位注射速尿治疗肝硬化腹水的疗效观察

目的:观察穴位注射速尿治疗肝硬化腹水的临床效果,寻求治疗肝硬化腹水的理想的治疗方式。方法:取穴足三里、三阴交、肾俞注射速尿20-40mg。结果:疗效显著经。统计学处理P<0.05据有显著差异。讨论:穴位注射速尿治疗肝硬化腹水,操作简单且用药剂量小,副作用小,安全性高疗效显著。     

Structural characterization of the cell wall binding domains of Clostridium difficile toxins A and B; evidence that Ca2+ plays a role in toxin A cell surface association

Clostridium difficile (C.difficile) is a nosocomially acquired intestinal bacillus which can cause chronic diarrhea and life-threatening colitis. The pathogenic effects of the bacillus are mediated by the release of two toxins, A and B. The C-terminal portions of both toxins are composed of 20 and 30 residue repeats known as cell wall binding (CWB) domains. We have cloned and expressed the CWB-domains of toxins A and B and several truncated CWB-domain constructs to investigate their structure and function. The smallest CWB-domain that folded in a cooperative manner was an 11 repeat construct of toxin A. This differentiates the C-terminal domains of toxins A and B from the CWB-domain of Streptococcus pneumoniae LytA, which only requires six repeats to fold. The 11 repeat toxin A construct bound Ca2+ directly with millimolar affinity and interacted with mammalian cell surfaces in a concentration and Ca2+-dependent fashion. Millimolar Ca2+ levels also accelerated toxin mediated CHO cell killing in an in vitro cell assay. Together, the data suggest a role for extracellular Ca2+ in the sensitization of toxin A/cell-surface interactions.