Assessing the redundancy of MADS-box genes during carpel and ovule development

Carpels are essential for sexual plant reproduction because they house the ovules and subsequently develop into fruits that protect, nourish and ultimately disperse the seeds. The AGAMOUS (AG) gene is necessary for plant sexual reproduction because stamens and carpels are absent from ag mutant flowers. However, the fact that sepals are converted into carpelloid organs in certain mutant backgrounds even in the absence of AG activity indicates that an AG-independent carpel-development pathway exists. AG is a member of a monophyletic clade of MADS-box genes that includes SHATTERPROOF1 (SHP1), SHP2 and SEEDSTICK (STK), indicating that these four genes might share partly redundant activities. Here we show that the SHP genes are responsible for AG-independent carpel development. We also show that the STK gene is required for normal development of the funiculus, an umbilical-cord-like structure that connects the developing seed to the fruit, and for dispersal of the seeds when the fruit matures. We further show that all four members of the AG clade are required for specifying the identity of ovules, the landmark invention during the course of vascular plant evolution that enabled seed plants to become the most successful group of land plants.     

Biomimic organ architectures and functions by assembling organoid models

An artificial organ is a synthetic device implanted into the living body as a substitute for a diseased organ.It is a long-term dream toward prolonging life by ...     

生物信息学在搜索水稻新基因及其功能预测中的运用

为了利用生物信息学探索网上克隆基因与预测基因功能的新方法,用本实验室原有的一段626bp片段在genebank的核酸数据库中进行同源性分析,并对blast所得的序列运用genscan等软件进行序列分析并预测新基因,由在网上数据库中的验证可知预测得到的新基因功能与水稻抗性相关.将该序列翻译成蛋白质并利用网上数据库进行功能预测,初步断定该蛋白是与水稻抗性相关的穿膜蛋白.同时也验证了用生物信息学预测新基因及其功能是极为有效和简便的一种方法.     

论B2C与C2C两种模式的融合和发展趋势

目前电子商务流行B2C和C2C两种模式。通过对当当网和淘宝网的分析,不难发现,B2C和C2C这两种模式各有优缺点,具有很强的互补性。从发展趋势来看,伴随而来的将是一种全新的电子商务运营模式,一个跨模式的全方位电子商务平台很快就会诞生;融合B2C和C2C,不仅可能,而且将是未来电子商务发展的必然趋势。     

B_(13)C_2和B_7C_8低压缩性的第一性原理计算研究

采用基于密度泛函理论的第一性原理计算方法,研究了B13C2(B12CBC)中B12二十面体极地位置的所有B原子被C原子取代后材料的性质变化.通过对比计算研究发现,取代后每个B6C6二十面体中赤道原子同赤道原子间、极地原子同极地原子间的电荷密度减小﹑Mulliken布局数由正值变为负值,说明它们由成键态转变为反键态,相互作用减弱;而极地原子同赤道原子间,以及相邻二十面体极地原子间的电荷密度相对增加﹑化学键长变短﹑sp轨道杂化进一步显著,说明它们的相互作用增强.结果造成材料的体弹模量增大、剪切模量减小;材料由半导体性过渡到金属性;电荷密度由B12二十面体相对均匀分布,转为向两极集中局域,而使主要影响材料理论硬度的最弱化学键等的计算硬度减弱、材料的理论硬度减小.     

C60的热力学函数与分子结构

在已获得的C     

Primary structure and expression of a product from cut, a locus involved in specifying sensory organ identity in Drosophila

In the absence of cut gene activity in Drosophila, external sensory organs are transformed into chordotonal organs. Here we show that the cut locus encodes a large protein containing a homoeodomain and is expressed in nuclei of cells in external sensory organs but not in cells within chordotonal organs.     

Morphogenetic genes C and Nu3 overlap in bacteriophage lambda

In bacteriophage lambda, genes C and Nu3, two of the four cistrons which are essential for normal prohead formation, have overlapping nucleotide sequences. These genes are translated in the same reading frame so that the Nu3 protein is identical to the COOH-terminal one-third of the C protein. This structural relationship may provide for the functional interaction of the C and Nu3 proteins through their regions of structural homology during prohead assembly. The in-phase overlapping organisation of genes may constitute a general strategy to facilitate the mutual interaction of a pair of proteins through their common structural domains.     

C3S-C2.75B1.25A3S--C2S-C3A-B2O3体系熟料组成与性能的研究

设计了C3S-C2．7581．25A3S-C2S-C3A-B2O3体系组成的水泥熟料,实验以分析纯化学试剂为原料,在1350℃煅烧并保温1h。结果表明,在该熟料体系中阿利特、硫铝酸钡钙、贝利特和铝酸三钙等矿物的最佳组成分别为50％、10％、25％和15％,B2O3的适宜掺量为2％。在最佳组成和制备工艺条件下,所制的阿利特-硫铝酸钡钙水泥的1d、3d和28d抗压强度分别达到21．3MPa、48．1MPa和80．8MPa,展现良好的早期力学性能。同时还研究了氟化钙对该体系水泥熟料的影响,并利用SEN-EDS、XRD等测试手段对熟料的组成、结构及性能进行了分析研究。     

C18B2的结构和稳定性

本文利用密度泛函理论(DFT),在B3LYP/6-31G 水平上对C18B2的三种构型(单环,碗状和fullerene)的37个异构体进行了几何优化计算,得到了C18B2的最稳定构型为具有fullerene结构的F1＿3结构,比较了C20和C18B2的电荷布居,发现C18B2的稳定性与电荷布居数和两个硼原子沿化学键的距离密切相关.     

Hepatitis B virus genes and their expression in E. coli.

A composite DNA sequence of regions of hepatitis B virus, determined from a series of recombinant plasmids, reveals the genes for the surface antigen and the core antigen of the virus. The sequence of the core antigen shows it to be a DNA binding protein. The core antigen gene is expressed in Escherichia coli and when injected into rabbits the bacterial product induces antibodies which react with core antigen isolated from human sources.     

Risk Analysis and Consumer Protection in B2C Transactions

Recent studies have shown that the perceived lack of security is a major obstacle to the wider acceptance of e-commerce. To overcome this barrier, businesses need to implement comprehensive consumer protection systems that protect consumers during every stage of the purchasing process. This paper used the consumer behaviour model as the basis for analysing risks in Bussiness-to-Consumer (B2C) transactions. Four categories of risks were identified: information, agreement, payment and delivery risk. By combining these risk categories with the three dimensions of management, technology and legislation, a comprehensive B2C consumer protection framework is developed.     

基于B/C/S模式的MIS系统构建及应用

对C/S模式和B/S模式的工作特点进行了分析,并根据MIS系统中用户对信息处理的实际要求,给出了基于B/C/S模式的信息管理系统的构建方法,该方法充分利用了C/S模式和B/S模式各自的优势。最后,通过实例展示了这一方法在学籍管理系统中的具体应用。     

H2分子X1∑+g,B1∑+u和C1∏u态的势能函数

使用SAC/SAC-CI方法,利用D95++**、6-311++g**以及cc-PVTZ等基组,对H2分子的基态X1+∑+g、第二激发态B1∑u+u及第三简并激发态C1∏u的平衡结构和谐振频率进行了优化计算.通过对三个基组的计算结果的比较,得出了cc-PVTZ基组为三个基组中的最优基组的结论;使用cc-PVTZ基组,利用SAC的GSUM(Group Sum of Operators)方法对基态X1∑+g、SAC-CI的GSUM方法对激发态B1∑+u和C1∏u进行单点能扫描计算,用正规方程组拟合Murrell-Sorbie函数,得到了相应电子态的完整势能函数;从得到的势能函数计算了与基态X1∑+g、第二激发态B1∑+u和第三简并激发态C1∏u相对应的光谱常数(Be,αe,ωe和ωeχe),结果与实验数据基本一致.     

H2分子X1∑+g,B1∑+u和C1∏u态的势能函数

使用SAC/SAC-CI方法,利用D95 **、6-311 g**以及cc-PVTZ等基组,对H2分子的基态X1 ∑ g、第二激发态B1∑u u及第三简并激发态C1∏u的平衡结构和谐振频率进行了优化计算.通过对三个基组的计算结果的比较,得出了cc-PVTZ基组为三个基组中的最优基组的结论;使用cc-PVTZ基组,利用SAC的GSUM(Group Sum of Operators)方法对基态X1∑ g、SAC-CI的GSUM方法对激发态B1∑ u和C1∏u进行单点能扫描计算,用正规方程组拟合Murrell-Sorbie函数,得到了相应电子态的完整势能函数;从得到的势能函数计算了与基态X1∑ g、第二激发态B1∑ u和第三简并激发态C1∏u相对应的光谱常数(Be,αe,ωe和ωeχe),结果与实验数据基本一致.     

B282C电子商务模式与基于J2EE设计架构的电子商务平台

B282C电子商务模式是互联网信息时代市场新型商务交易需求与电子信息技术开发利用的产物．基于J2EE电子商务平台开发技术架构的B282C电子商务平台具有稳定运行、交互性能高、易于维护、可扩展和安全性良好的特点,可以较好地满足当前电子商务交易复杂的企业级应用需要．