Phase variation in Bordetella pertussis by frameshift mutation in a gene for a novel two-component system

Bordetella pertussis, the aetiological agent of whooping cough, coordinately regulates the expression of many virulence-associated determinants, including filamentous haemagglutinin, pertussis toxin, adenylyl cyclase toxin, dermonecrotic toxin and haemolysin. The coordinate regulation is apparent in the repression of synthesis of these determinants in response to environmental stimuli; a phenomenon known as antigenic or phenotypic modulation. B. pertussis also varies between metastable genetic states, or phases. There is a virulent phase in which virulence-associated determinants are synthesized, and an avirulent phase in which they are not. Previous studies have shown that a genetic locus, vir, is required for expression from many virulence-associated loci, and that replacing the cloned vir locus in trans can restore the virulent phase phenotype to spontaneously occurring avirulent phase strains. Here, we show that phase variation in one series of strains is due to a frameshift mutation within an open reading frame that is predicted to code for a Vir protein product. The deduced protein sequence is similar to both components of the 'two-component' regulatory system which control gene expression in response to environmental stimuli in a range of bacterial species.     

A frameshift mutation in NOD2 associated with susceptibility to Crohn's disease

Crohn's disease is a chronic inflammatory disorder of the gastrointestinal tract, which is thought to result from the effect of environmental factors in a genetically predisposed host. A gene location in the pericentromeric region of chromosome 16, IBD1, that contributes to susceptibility to Crohn's disease has been established through multiple linkage studies, but the specific gene(s) has not been identified. NOD2, a gene that encodes a protein with homology to plant disease resistance gene products is located in the peak region of linkage on chromosome 16 (ref. 7). Here we show, by using the transmission disequilibium test and case-control analysis, that a frameshift mutation caused by a cytosine insertion, 3020insC, which is expected to encode a truncated NOD2 protein, is associated with Crohn's disease. Wild-type NOD2 activates nuclear factor NF-kappaB, making it responsive to bacterial lipopolysaccharides; however, this induction was deficient in mutant NOD2. These results implicate NOD2 in susceptibility to Crohn's disease, and suggest a link between an innate immune response to bacterial components and development of disease.     

Salen-金属配合物与DNA中碱基的相互作用

参照文献方法,合成了N,N’-双(2-羟基-1-萘甲醛)缩邻苯二胺、乙二胺和1,3-丙二胺的3种Salen配体及其与Mn(Ⅲ)、Co(Ⅲ)形成的6种配合物,探究了它们对碱基的荧光猝灭效应.结果表明,对于同一碱基来说,Mn(Ⅲ)配合物比Co(Ⅲ)更易使碱基发生荧光猝灭;同种配合物与不同的碱基作用时,其猝灭强度大小顺序为胞嘧啶腺嘌呤鸟嘌呤,呈现出配合物对碱基作用的选择性;配合物的结构对荧光的猝灭也有影响.     

异羟肟酸过渡金属配合物仿加氧酶研究进展

综述了异羟肟酸过渡金属配合物仿加氧酶研究进展新进展,重点综述了异羟肟酸过渡金属配合物的结构对其二氧加合性能、催化苯乙烯环氧化性能以及催化乙苯、二甲苯和异丙苯均相氧化性能的影响.     

水杨醛缩氨基酸、联吡啶配合物的电化学合成

以水杨醛缩L-苯丙氨基酸Schiff碱和2,2'-联吡啶为配体的非水溶剂中,用金属Cu、Zn、Ni为"牺牲"阳极,用电化学方法电解合成了Cu(Ⅱ)、Zn(Ⅱ)、Nj(Ⅱ)配合物.讨论了电化学合成的主要影响因素.通过元素分析、红外光谱、紫外光谱、热分析等对配体和配合物进行了表征,确定了配合物的化学组成,同时测定了Ni(Ⅱ)配合物的电化学性质.     

乙二醛邻氨基苯甲酸希夫碱过渡金属配合物的合成和表征

研究了过渡金属钴（Ⅱ）、镍（Ⅱ）、铜（Ⅱ）、锌（Ⅱ）与乙二醛双邻氨基苯甲酸希夫碱（H2L）配合物的合成,并用元素分析、摩尔电导、红外光谱、紫外-可见光谱、X-射线衍射物相分析、热重分析等测试手段进行了表征.结果表明,这是一类新的配合物,其组成为*4H2O(M=Co、Ni、Cu、Zn,L=乙二醛双邻氨基苯甲酸根),中心金属离子与希夫碱配体中的亚胺氮和羧酸根中的氧原子发生配位,配位数为4.     

基于基矩阵和基矩阵集合的分离网络优化模型

分离网络综合问题因其巨大的搜索空间导致优化计算的高复杂性。为提高分离网络综合问题的求解效率,该文提出了基矩阵和基矩阵集合的概念,建立了分离网络优化模型。列队竞争算法因其具有快速搜索到全局最优解或近似全局最优解的优点,而被用来求解该分离网络优化模型。用该文提出的方法对两个较大规模的分离网络综合问题进行了求解。计算结果证明:该方法能有效减少变量数,提高全局最优解的搜索效率。     

水杨醛希夫碱配合物及其修饰MCM-41的合成及表征

目的　用γ 氨丙基修饰的介孔分子筛MCM 41合成几种配合物并进行了组装。方法　通过XRD,UV Vis,IR对合成的配合物表征。结果　过渡金属Mn(Ⅲ),Fe(Ⅲ)的N,N 双 5 溴水杨醛缩乙二胺(5Br H2salen),N,N 双 5 溴水杨醛缩邻苯二胺(5Br H2salphen),N,N 双 5 氯水杨醛缩邻苯二胺(5Cl H2salphen)的Schiff碱配合物[FeCl(5Br salen)]·H2O,[MnCl(5Br salen)]·H2O,[FeCl(5Br salphen)]·H2O和[MnCl(5Cl salphen)]·H2O组装进入了MCM 41分子筛。结论　γ 氨丙基修饰了的介孔分子筛MCM 41有利于希夫碱配合物的组装。     

稀土水杨醛缩苯丙氨酸盐邻菲咯啉配合物的合成、表征及抗菌活性

以稀土氯化物、席夫碱水杨醛缩苯丙氨酸和邻菲咯啉为配体,在无水乙醇溶液中反应,制备了一类新型稀土三元配合物,通过元素分析、摩尔电导、红外光谱、紫外光谱和热重一差热分析,确定了该配合物的化学组成：RE（L）（Phen）Cl（H2O）（RE=Pr^3＋,Nd^3＋,Er^3＋;L=席夫碱水杨醛缩苯丙氨酸）．通过抗菌实验对其抑菌效果进行研究,结果表明配合物对大肠杆菌、金黄色葡萄球菌有较强的抑制作用,抗菌谱广．     

N-亚水杨基甘氨酸席夫碱与稀土亚硒酸盐配合物的合成与表征

在水溶液中合成了通式为Ｌｎ２（Ｓａｌ－Ｇｌｙ）２ＳｅＯ３．２Ｈ２Ｏ（Ｌｎ＝Ｌａ,Ｎｄ,Ｇｄ;Ｓａｌ＝亚水杨基;Ｇｌｙ＝甘氨酸）、亚硒酸根参与配位的氨基酸稀土配合物,用元素分析、摩尔电导、红外光谱、紫外－可见光谱和差热－热重分析对其组成和性质进行了研究。     

新型硫代磷酰肼席夫碱及其金属配合物的合成与生物活性

合成了5，5—二甲基—1，3—二氧杂己内硫代磷酰肼缩邻香草醛席夫碱及其Cu(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)和Co(Ⅱ)的金属配合物，用元素分析、IR、摩尔电导和电子光谱对所有化合物进行了表征，对席夫碱配体还进行了^1H NMR和MS结构表征，给出了化合物可能的空间结构,测定了化合物对水稻幼苗POD酶活力的影响。     

改良土填筑过渡段基床底层的动力特性分析

通过动三轴试验及拟合参数法获得软岩改良土的动强度,以允许动强度为标准,评判软岩改良土可以作为基床底层以及路堤本体填料.同时,基于D'Alembert原理的能量弱变分和整体Lagrange格式,建立路桥过渡段半空间垂向耦合的动力计算模犁,进一步分析不同列车速度下路桥过渡段的动态响应特征,并通过现场实测数据对比验证模型的正确性.研究结果表明:在列车荷载下,竖向动位移幅值波动范围为0.05-0.35 mm,小于控制值;弹性应变幅值小于3×10~(-5),处于小变形阶段;竖向动应力幅值波动范围为15.5～19.5 kPa,远小于改良土的动强度;采用刚性过渡较合理,掺入5%水泥的改良土可用于其基床底层及路基本体的填筑.     

Synthesis, structure and superoxide dismutase activity of two self-assembly transition metal complexes containing a tridentate amino-Schiff base deviating from salicylaldehyde with glycine

Two new transition metal （Cu, Ni） complexes with amino-Schiff base ligand, （CgH7NO3）Cu（C14H12N2）.H2O （1） and （C9HTNO3）Ni（C3H4N2）3.H2O （2）, have been designed and synthesized in ethanol solution at room temperature. Both of the complexes have been characterized by elemental analysis, IR spectra, UV-vis spectroscopy and X-ray single crystal diffraction. For complex 1, the coordination environment of the central copper atom is a distorted square pyramid, and one-dimensional chain is formed through the inter-molecular hydrogen bonds （O4-H2W…O3, O4…H2W…O3#1 （#1： -x＋1, y, -z＋3/2）） and weak interactions （∏-∏ stacking interaction） between the phenyl rings. For complex 2, the nickel atom is 6-coordinated and in a distorted octahedral environment, and a discrete hydrogen-bond cluster （four molecules are connected by hydrogen bonds into a group） is formed via two types of intra-molecular hydrogen bonds （O-H...O, N-H...O） and inter-molecular hydrogen bonds （O-H...O, N-H...O）.     

矿山地质环境数据库建设

论述了矿山地质环境数据库建设的策略,建库应遵循的基本原则,重点阐述了矿山地质环境数据库建设的总体方案.     

Bundling strategies for platforms with an installed base

As an emerging platform, hardware/software platforms differ from traditional retail platforms because they require consumers to spend a certain amount of money accessing them. Therefore, an installation base is created. Considering the game console as an example, only consumers with an installation base can purchase a third-party game product on the platform. Otherwise, consumers will be unable to play games. It is generally believed that the existence of an installed base will benefit third-party content providers, and at the same time, it will not benefit platform manufacturers. Therefore, it can be observed that game platforms often bundle new consoles with third-party content, forcing consumers with installed bases to purchase a new console. Thus, building a model to study the impact of the installation based on the bundling strategy of the video game platform and to analyze the optimal pricing and profit under different bundling strategies is meaningful. Our study analyzed the impact of the installed base under different bundling strategies and found that the installed base dose not always have a positive impact on platform manufacturers. The study also analyzed the equilibrium of competing platform manufacturers and found that, under certain conditions, both the bundling-bundling strategy and the unbundling-unbundling strategy may exist as equilibrium.     

3-氯苯甲醛丙氨酸席夫碱及其3d-过渡金属配合物的研究

合成了3－氯苯甲醛丙氨酸席夫碱及其与Cu（Ⅱ），Ni（Ⅱ）、Co（Ⅱ）、Zn（Ⅱ）离子所形成的配合物；以元素分析、摩尔电导、热重、红外光谱、^1HNMR谱等手段研究了化合物的组成和配位环境；对所合成的化合物进行了抑制超氧自由基的初步实验，发现3－CACu、3－CANi有较强的抑制超氧离子自由基的作用，但与SOD相比相差较远，其余化合物几乎没有作用。