sFcγRⅡb蛋白结合肽的筛选与鉴定

FcγRⅡb是免疫球蛋白G受体( FcγR)中唯一的抑制型受体,在免疫反应的负性调节方面发挥重要作用.为了筛选sFcγRⅡb的蛋白结合肽,以重组sFcγRⅡb蛋白为靶分子,采用噬菌体肽库展示技术对sFcγRⅡb结合肽进行筛选.利用ELISA鉴定每轮洗脱噬菌体与sFcγRⅡb蛋白亲和力,经过4轮筛选,挑取40个噬菌体克隆进行序列测定,获得28种不同的12肽序列.经ELISA法鉴定噬菌体与sFcγRⅡb蛋白结合活性,得到sFcγRⅡb蛋白高特异性、高亲和力结合肽FHKMPWYMSMYY,为进一步研究FcγRⅡb的作用机制和探索结合肽的功能提供实验基础.     

纤锌矿氮化物半导体椭球形量子点杂质态

考虑纤锌矿结构氮化物半导体材料的单轴异性后,在有效质量近似下,利用变分法研究了无限高势垒近似下GaN,AlN和InN椭球形量子点中的杂质态,导出了杂质态结合能随量子点半径和椭球率变化的关系.数值计算结果发现,杂质态结合能随着量子点半径和椭球率的增加而减小.     

双阴离子吗啉型离子液体结构性能的量子化学研究

用密度泛函理论在B3LYP/6-31G*的计算水平上研究了同种阳离子不同阴离子或同种阴离子不同阳离子的吗啉型离子液体对其优化结构和结合能的影响.结果表明:同一种离子液体形成两种构型(mon构型和orth构型),阴阳离子间主要通过6个氢键相互作用,除了乙醇N-甲基吗啉二氯中最强的氢键是Cl-与O原子上的H原子形成的氢键外,其他两种阳离子,卤素离子与吗啉环上3位和4位碳上的氢质子之间的氢键作用最强;所有的反应均是放热反应,阴阳离子之间的相互作用能非常大,说明阴阳离子之间均形成较强的相互作用,不同的阴离子和阳离子对其结合能都有影响.     

浅谈木门生产中手糊薄木的工艺及其利弊

手糊薄木工艺是利用加热蒸发水分,使乳白胶产生胶结合作用的基本原理来完成的。本文主要从加工工艺及其利弊方面进行了简单的阐述。并总结工厂中的生产经验,简单的论述了其检验方法和不合格产品的处理方法。以便更大的提高产品的质量。     

卟啉衍生物TMPyP4与单链DNA的结合机理研究

通过圆二色谱、稳态吸收光谱、稳态荧光光谱和皮秒时间分辩荧光光谱研究了meso-四(4-(N-甲基吡啶基))卟啉(TMPyP4)与端粒DNA5′-TTAGGG-3′(S6)的结合机理.稳态光谱实验结果表明,在没有金属离子的Tris-HCl缓冲溶液中,S6DNA以单链的形式存在,TMPyP4与单链DNA的结合常数为1.51×106(mol/L)-1,饱和结合数为1.2.通过时间分辨荧光光谱对二者相互作用的机理进行了进一步研究,推测了TMPyP4与单链S6DNA之间的结合模式.     

Isolation of a strong matrix attachment region (MAR) and identification of its function in vitro and in vivo

Inclusion of MARs in transgene cassettes enhances their expression and reduces position-effect variations in the transgenic host. Four new MARs (TM2, TM3, AM1 and AM2) were isolated from tobacco and Arabidopsis by PCR method. The nuclei isolated from suspensioncultured cells of rice were used to prepare nuclear matrix. With a characterized MAR (TM1) as a positive control, the Matrix-MAR interactions were tested by an in vitro binding assay to identify the DNA sequences as MARs and their binding strength to nuclear matrix in vitro was compared. The results showed that TM2 and TM3 had stronger binding strength than TM1. To determine the functions of the four new MARs in vivo, binary vectors pBI121 carrying a uidA GUS reporter gene were modified with direct repeat MARs inserted on both sides of the reporter gene cassette and were transferred into tobaccos via Agrobacterium-mediated transformation procedure. Quantitative GUS assays of the transgenic tobaccos showed that when flanking a GUS reporter gene TM1, TM2, TM3 and AM1 increased uidA GUS gene expression level approximately 1.5-fold, 5-fold, 1.35-fold, 1.3-fold respectively and AM2 has no effect on gene expression. TM2 was found to be a strong MAR that could effectively increase gene expression level and could be used as an effective enhancing element to construct high efficient expression vectors. In this note the relations among the sequence features, binding strength in vitro and function in vivo of the five MARs were analyzed, and the potential significance of TM2 in plant genetic engineering was discussed.     

施主离子对抛物阱中束缚极化子的影响

从电子-声子相互作用的哈密顿量出发,采用改进的LLP方法研究了无限深抛物阱中束缚极子的极化势和结合能随施主离子位置z0的变化关系.结果表明,电子与施主离子间的距离不同,则极化势随施主离子位置的变化关系也不同.对于给定的阱宽,随着施主离子远离阱中心,束缚极化子的结合能迅速减小;阱宽不同,束缚极化子的结合能减小的程度不同.     

Ambiquitous behavior of rabbit liver lactate dehydrogenase

Summary Rabbit liver mitochondrial fraction shows lactate dehydrogenase activity. The enzyme can be released from particles by increasing the pH and the ionic strength of the medium. There is a narrow range of pH (6.8–7.4) and ionic strength (20–50 mM NaCl) in which the solubilization sharply increases. It has been shown that divalent anions (SO ₄ ^2– ) and cations (Mg²⁺, Ca²⁺) are highly effective specific solubilizing agents. NADH (1.5 mM) and ATP (1.0 mM) were effective in solubilizing 50% of the enzyme bound, whereas the same concentrations of the analogs NAD⁺ and ADP had little effect. Cytosolic lactate dehydrogenase bound to the mitochondrial fraction and a saturation of particles by enzyme was observed in all experiments performed. The in vitro binding requires a short period of incubation between the enzyme and particles and the binding is independent of the temperature in the 0–37°C range. Binding was prevented by 0.15 M NaCl. The bound enzyme is approximately 20% less active than the soluble one. The results described give support to the proposal that rabbit liver lactate dehydrogenase has an ambiquitous behavior, like other glycolytic enzymes, which have not a fixed intracellular localization.     

符号结构的关联网络构造与检索

本文用动态符号结构造一个数据递归分布表示的关联网络，以精馏中Ｎ＿组分分离方法生成为例，论述了关联网络构造的有关准则、定义、符号变量的约束函数；引入了模式映象的概念；对不定的ｍ＿枝与或图的检索给出了动态的递归算法．实验结果表明与期望相符．