Novel gene expressed during early embryogenesis of zebrafish identified by mRNA differential display

Following the revelation of the molecular mechanism of morphogenesis in fruitfly, research on the molecular mechanism of morphogenesis in vertebrate becomes the focus of developmental biology. The isolation of genes controlling the embryogenesis of zebrafish, a vertebrate model animal, is considered as an initial step toward investigating this issue. There are several approaches that can be used to isolate developmental genes, each of which is suited to a particular situation. In this note, mRNA differential display was utilized to demonstrate the mRNA differences among zebrafish embryos at 4, 5 and 6 h post fertilization (28.5℃, corresponding to oblong, dome and shield stages, respectively, called blastula, gastrula and neurula in this note). One cDNA tag that was specific to embryos at neurula stage was cloned and sequenced. After sequence comparison in Genbank, we found that this cDNA tag represents a novel gene. The expression of this gene in the developing zebrafish embryos was examined by whole mount in situ hybridization. The hybridization results confirmed that this gene was specifically expressed in zebrafish neurula embryos.     

Establishment of developmental precision and proportions in the early Drosophila embryo

During embryonic development, orderly patterns of gene expression eventually assign each cell in the embryo its particular fate. For the anteroposterior axis of the Drosophila embryo, the first step in this process depends on a spatial gradient of the maternal morphogen Bicoid (Bcd). Positional information of this gradient is transmitted to downstream gap genes, each occupying a well defined spatial domain. We determined the precision of the initial process by comparing expression domains in different embryos. Here we show that the Bcd gradient displays a high embryo-to-embryo variability, but that this noise in the positional information is strongly decreased ('filtered') at the level of hunchback (hb) gene expression. In contrast to the Bcd gradient, the hb expression pattern already includes the information about the scale of the embryo. We show that genes known to interact directly with Hb are not responsible for its spatial precision, but that the maternal gene staufen may be crucial.     

Proteome survey reveals modularity of the yeast cell machinery

Protein complexes are key molecular entities that integrate multiple gene products to perform cellular functions. Here we report the first genome-wide screen for complexes in an organism, budding yeast, using affinity purification and mass spectrometry. Through systematic tagging of open reading frames (ORFs), the majority of complexes were purified several times, suggesting screen saturation. The richness of the data set enabled a de novo characterization of the composition and organization of the cellular machinery. The ensemble of cellular proteins partitions into 491 complexes, of which 257 are novel, that differentially combine with additional attachment proteins or protein modules to enable a diversification of potential functions. Support for this modular organization of the proteome comes from integration with available data on expression, localization, function, evolutionary conservation, protein structure and binary interactions. This study provides the largest collection of physically determined eukaryotic cellular machines so far and a platform for biological data integration and modelling.     

真核基因选择性剪接机理的初步研究

真核基因表达调控是生命科学研究的前沿、热点。RNA的选择性剪接在真核基因表达调控中起着十分重要的作用。该文从已有数据出发 ,对真核基因的剪接机制以及选择性剪接的机制进行了初步的研究。结果表明 ,在真核基因的剪接过程中 ,可能存在一种“粗定位—细定位”的过程 ,即在剪接过程中首先有一粗略的定位过程 ,根据序列的嘌呤、嘧啶浓度特征寻找出剪接位点的大致位置 ;然后在这一基础上 ,根据几个保守碱基所提供的信息找到准确的剪接位点。这一结果对于进一步研究真核基因的剪接机制 ,特别是选择性剪接发生的机理有很大的启发。     

Drosophila RNAi screen identifies host genes important for influenza virus replication

All viruses rely on host cell proteins and their associated mechanisms to complete the viral life cycle. Identifying the host molecules that participate in each step of virus replication could provide valuable new targets for antiviral therapy, but this goal may take several decades to achieve with conventional forward genetic screening methods and mammalian cell cultures. Here we describe a novel genome-wide RNA interference (RNAi) screen in Drosophila that can be used to identify host genes important for influenza virus replication. After modifying influenza virus to allow infection of Drosophila cells and detection of influenza virus gene expression, we tested an RNAi library against 13,071 genes (90% of the Drosophila genome), identifying over 100 for which suppression in Drosophila cells significantly inhibited or stimulated reporter gene (Renilla luciferase) expression from an influenza-virus-derived vector. The relevance of these findings to influenza virus infection of mammalian cells is illustrated for a subset of the Drosophila genes identified; that is, for three implicated Drosophila genes, the corresponding human homologues ATP6V0D1, COX6A1 and NXF1 are shown to have key functions in the replication of H5N1 and H1N1 influenza A viruses, but not vesicular stomatitis virus or vaccinia virus, in human HEK 293 cells. Thus, we have demonstrated the feasibility of using genome-wide RNAi screens in Drosophila to identify previously unrecognized host proteins that are required for influenza virus replication. This could accelerate the development of new classes of antiviral drugs for chemoprophylaxis and treatment, which are urgently needed given the obstacles to rapid development of an effective vaccine against pandemic influenza and the probable emergence of strains resistant to available drugs.     

一种小功率开关稳压电源设计

本文设计了一种以电流型PWM控制器5L0380为控制核心的单端反激式开关稳压电源。重点给出EMI滤波器、整流电路、变压器、控制电路、反馈电路的参数设计。实验结果表明,所制作的电源具有稳压性能优良、纹波小、电压调整率和负载调整率小等优点。     

Function of Rieger syndrome gene in left-right asymmetry and craniofacial development.

Rieger syndrome, an autosomal dominant disorder, includes ocular, craniofacial and umbilical abnormalities. The pitx2 homeobox gene, which is mutated in Rieger syndrome, has been proposed to be the effector molecule interpreting left-right axial information from the early embryonic trunk to each organ. Here we have used gene targeting in mice to generate a loss-of-function allele that would be predicted to result in organ randomization or isomerization. Although pitx2-/- embryos had abnormal cardiac morphogenesis, mutant hearts looped in the normal direction. Pitx2-/- embryos had correctly oriented, but arrested, embryonic rotation and right pulmonary isomerism. They also had defective development of the mandibular and maxillary facial prominences, regression of the stomodeum and arrested tooth development. Fgf8 expression was absent, and Bmp4 expression was expanded in the branchial-arch ectoderm. These data reveal a critical role for pitx2 in left-right asymmetry but indicate that pitx2 may function at an intermediate step in cardiac morphogenesis and embryonic rotation.     

溴化锂制冷机在工程应用中的分析与探讨

通过对各种常用的溴化锂吸收式制冷机在应用中存在的问题进行分析，提出了以溴化锂吸收式制冷机为冷源的中央空调工程的设计及运行管理中应注意的几个问题．     

电机通风系统风量问题的新型迭代解法

研究了含风压源的复杂风网中风量的求解方法，提出了统一的风网矩阵模型和迭代公式，并给出了两个算例。结果表明，在迭代初值任意选取的情况下，经过几次迭代就可使各支路的风量收敛于稳定值，模型适用于复杂通风结构电机的风量计算。     

Research on transformation from UML statechart to interface automata

This paper studies the problem of deriving an interface automata model from UML statechart, in which, interface automata is a formaliged model for describing component behavior in an open system, but there is no universal criterion for deriving behavior from component to construct the model. UML is a widely used modeling standard, yet it is very difficult to apply it to system verification and testing directly for its imprecise semantics. After analyzing the expression ability of the two models, several transformation rules are defined and each step of transformation is described in detail, after that, the approach is illustrated with an example. The paper provides a method for acquiring interface automata and lays the foundation for related research.     

2－机器FlowShop随机调度问题

本文讨论了２－机器ＦｌｏｗＳｈｏｐ调度问题，在假定同一工件在不同机器上的加工时间为同分布的随机变量且加工时间在随机意义下可以排序时，给出了等待时间差的绝对值总和的期望最小的最优排序的若干性质。     

癌症基因表达数据的熵度量分类方法

基因芯片技术的出现和发展为生物医学领域带来了深远影响,运用分类方法研究其产生的海量数据对癌症的分类及治疗有重要意义.该文提出一种利用熵度量作为指标进行癌症基因表达数据特征提取的方法.首先对基因表达数据进行筛选并计算各个基因的熵,然后提取出熵最大的若干基因作为特征基因,并用支持向量机进行分类.对前列腺癌基因表达数据的留一法以及分组法实验都证明了该方法的有效性.     

A Step Motor Driver For the Let-off Mechanism of Looms

It is simple with good quality,and versatile with low costto use a step motor drive for the let-off mechanism ofweaving machines.This paper deals with the investiga-tion of this mechanism about the warp tension detectingand the design of the step motor drive system,which ispracticable,reliable and with low power consumption.So it is worthwhile to spread and push forward its appli-cation.     

Predictive models of molecular machines involved in Caenorhabditis elegans early embryogenesis

Although numerous fundamental aspects of development have been uncovered through the study of individual genes and proteins, system-level models are still missing for most developmental processes. The first two cell divisions of Caenorhabditis elegans embryogenesis constitute an ideal test bed for a system-level approach. Early embryogenesis, including processes such as cell division and establishment of cellular polarity, is readily amenable to large-scale functional analysis. A first step toward a system-level understanding is to provide 'first-draft' models both of the molecular assemblies involved and of the functional connections between them. Here we show that such models can be derived from an integrated gene/protein network generated from three different types of functional relationship: protein interaction, expression profiling similarity and phenotypic profiling similarity, as estimated from detailed early embryonic RNA interference phenotypes systematically recorded for hundreds of early embryogenesis genes. The topology of the integrated network suggests that C. elegans early embryogenesis is achieved through coordination of a limited set of molecular machines. We assessed the overall predictive value of such molecular machine models by dynamic localization of ten previously uncharacterized proteins within the living embryo.     

Expression of a transfected human c-myc oncogene inhibits differentiation of a mouse erythroleukaemia cell line

The Friend-virus-derived mouse erythroleukaemia (MEL) cell lines represent transformed early erythroid precursors that can be induced to differentiate into more mature erythroid cells by a variety of agents including dimethyl sulphoxide (DMSO). There is a latent period of 12 hours after inducer is added, when 80-90% of the cells become irreversibly committed to the differentiation programme, undergoing several rounds of cell division before permanently ceasing to replicate. After DMSO induction, a biphasic decline in steady-state levels of c-myc and c-myb messenger RNAs occurs. Following the initial decrease in c-myc mRNA expression, the subsequent increase occurs in, and is restricted to, the G1 phase of the cell cycle. We sought to determine whether the down-regulation is a necessary step in chemically induced differentiation. Experiments reported here indicate that expression in MEL cells of a transfected human c-myc gene inhibits the terminal differentiation process.     

汽轮发电机组故障诊断的并行关联模型

提出了一种新的汽轮发电机组故障诊断模型－并行关联诊断模型（ＰＲＤＭ）。ＰＲＤＭ将复杂问题分解成为相对简单又相互关联的子问题,再根据各个子问题的具体特性由多个相对独立的子系统并行协同工作,简化了求解的复杂程度。和传统的诊断专家系统相比,ＰＲＤＭ具有知识维护容易,推理机制灵活,推理效率高的优点,智能化程度有了进一步提高,适用于大型复杂系统的故障诊断。ＰＲＤＭ已经成功地应用于汽轮发电机组的故障诊断。