一种具有抗肿瘤活性的新型尿激酶原Kringle结构域变体蛋白的研究

利用PCR技术获得人尿激酶原Kringle结构域基因,将其克隆至具有T7启动子的表达质粒pET29a中,并进而插入plasminogen Kringle 5一段16肽片段构建了其变体,重组质粒转化至大肠杆菌BL21中,经IPTG诱导表达,其产物以包涵体形式存在．通过体外复性,得到可溶性的prourokinase Kringle及其变体．所得蛋白质经过动物肿瘤模型测活,确定变体蛋白具有抑制肿瘤生长作用．     

Generation of mutants with developmental defects in zebrafish by ENU mutagenesis

As a good model for studying early development of vertebrates, zebrafish (Danio rerio) is attracting more and more attention. Following ENU mutagenesis, 320 F2 families were established. Mutants, which showed defects in epiboly, axis, somite, head, and cardiac and blood systems, were identified by observing morphological changes in F3 embryos. So far, 35 mutant lines have been established, the majority of which showed anomalies in axis and somite formation. These mutant lines provide useful genetic resources for cloning of the mutant genes and for studying mechanisms of early development of vertebrate embryos.     

一种限定记忆的自适应扩展Kalman滤波器

为解决扩展卡尔曼滤波器(EKF)鲁棒性差,且无法实时精确跟踪系统突变状态的问题,研究一种基于限定记忆滤波的自适应EKF算法。算法将EKF与限定记忆滤波器相融合,减小旧量测数据对滤波效果的影响,提高估计精度;引入自适应因子与渐消因子,通过实时调节新旧滤波增益阵以及预测状态值,精确地跟踪系统突变状态。仿真实例表明,强跟踪算法与经典EKF算法相比,自适应EKF算法鲁棒性好,滤波精度高,能够有效地跟踪系统突变状态。     

Crystallization and preliminary crystallographic analyses of human insulin mutant B9(Ser→Asp) in different aggregation forms

B9(Ser→Asp) insulin, one of the fast-acting insulin mutants produced by protein engineering, has been crystallized. Three crystal forms have been obtained, which belong to or-thorhombic, tetragonal and rhombohedral system, respectively. Each crystal form contains different aggregation units of the mutant, i.e. dimer or hexamer. The diffraction data of the former two have been collected beyond 0.2 nm resolution. The structural analyses and comparisons will provide some information about insulin' s self-association and the structural basis of the fast absorption produced from the mutation.     

基于门控循环单元神经网络的浆液pH的预测建模

吸收塔内浆液的PH值是影响燃煤电厂湿法脱硫系统效率的重要参数。燃煤电厂的湿法脱硫系统具有大滞后、非线性、强耦合等特征,因而其吸收塔浆液的PH值很难实现精准控制。本文利用门控循环单元（gated recurrent unit, GRU）神经网络在处理时间序列数据的优越性,对吸收塔内的浆液PH值进行预测建模,通过将燃煤电厂采集的影响浆液PH值的变量数据作为模型的输入,对模型进行训练处理,获得吸收塔内浆液PH值的预测模型。将预测模型应用于辽宁省华能营口电厂600MW机组湿法脱硫智能控制系统中吸收塔内浆液PH值的预测。结果表明相比于反向传播（back propagation, BP）神经网络模型、径向基函数（radial basis function, RBF）神经网络、循环神经网络（recurrent neural network, RNN）和长短期记忆（long and short term memory, LSTM）神经网络,该模型精确度更高,实用性更强。     

大肠杆菌DH5α及其耐乙酸突变株DA19在碳源限制培养基中乙酸的积累

在碳源限制的基本培养基和复合培养基中分别对大肠杆菌DH5α及其耐乙酸突变株DA19进行分批培养,两者在复合培养基中的乙酸产量均明显高于基本培养基,相同培养基中DH5α的乙酸产量高于DA19。基本培养基中分批培养的物料衡算显示:DH5α通过三羧酸(TCA)循环和呼吸链提供能量的葡萄糖低于DA19,通过乙酸形成途径的量则增加,表明DA19的TCA循环或电子传递链氧化能力有所提高,而DH5α的TCA循环或电子传递链的能力限制使更多的葡萄糖通过形成乙酸来提供能量。能量需求的计算结果表明:在碳源限制的复合培养基中,有机氮源的异化代谢提供了部分能量,在丙氨酸和谷氨酸为碳氮源的基本培养基中的分批培养也表明氨基酸的异化代谢对乙酸产生的影响。     

黑曲霉的紫外诱变及其液体发酵产木聚糖酶

黑曲霉A,为出发菌株,经紫外线诱变处理,采用平板培养筛选,获得一产木聚糖酶活力高的茵株.实验通过氮源含量,碳源含量,培养基含量和发酵时间对液体发酵产木聚糖酶的影响分析,得出产木聚糖酶的最优条件,即培养时间60 h,接种量5 mL细胞浓度为5×10°个/mL孢子悬液,温度为28℃,氮源质量浓度4 g/L,底物量为0.55 g,培养液70 mL,此条件下生产的木聚糖酶活力可达到58.305 u/mL.     

Tauroursodeoxycholic acid prevents E22Q Alzheimer’s Aβ toxicity in human cerebral endothelial cells

The vasculotropic E22Q mutant of the amyloid-β (Aβ) peptide is associated with hereditary cerebral hemorrhage with amyloidosis Dutch type. The cellular mechanism(s) of toxicity and nature of the AβE22Q toxic assemblies are not completely understood. Comparative assessment of structural parameters and cell death mechanisms elicited in primary human cerebral endothelial cells by AβE22Q and wild-type Aβ revealed that only AβE22Q triggered the Bax mitochondrial pathway of apoptosis. AβE22Q neither matched the fast oligomerization kinetics of Aβ42 nor reached its predominant β-sheet structure, achieving a modest degree of oligomerization with a secondary structure that remained a mixture of β and random conformations. The endogenous molecule tauroursodeoxycholic acid (TUDCA) was a strong modulator of AβE22Q-triggered apoptosis but did not significantly change the secondary structures and fibrillogenic propensities of Aβ peptides. These data dissociate the pro-apoptotic properties of Aβ peptides from their distinct mechanisms of aggregation/fibrillization in vitro, providing new perspectives for modulation of amyloid toxicity. Received 20 November 2008; received after revision 12 December 2008; accepted 12 January 2009     

卫星搭载凤仙花诱发的院3突变株后代小孢子的染色体数目变化研究

凤仙花种子经"神舟"4号卫星搭载后,在SP1代中发现一个减数分裂异常和小孢子内染色体数目非减半突变株,本文对其后代的花色变化和染色体数目变化进行了研究。发现粉红花和红花突变系小孢子染色体在7条左右,而蓝紫色突变系则平均在10以上,二者有较大差异。在花粉粒大小方面则有相似的结果。     

幼叶黄化油菜(Brassica napus L.)突变体Cr3529叶绿体超微结构观察

对油菜Cr3529叶片细胞中的叶绿体数目及结构进行了显微及亚显微观察。结果显示，突变与野生型细胞中叶绿体的数目没有显著性的差异，但叶绿体的结构有较大的差异，较之正常油菜，Cr3529油菜叶绿体基粒类囊体数较少，基质类囊体数较多，而且，在基粒类囊体中基粒片层数也较少，大部分基粒只有几个片层，基粒的平均片层数为5．46，约为野生型的一半，作者认为，较少的基粒片层数可能是引起Cr3529油菜叶绿素含量减少，并最终导致植株显著减产的重要原因。