红细胞聚集的微观力学分析

红细胞聚集是一种细胞间表面电荷群决定的互相吸附 ,是由分散的单个细胞发展而成的三维网络结构 ,是血液流变学中一个重要的研究课题。从微观力学角度对红细胞的聚集进行了分析 ,讨论了影响血液屈服应力的因素     

河蟹大眼幼体至Ⅲ期幼蟹对蛋白质、脂肪、复合矿物盐及维生素适宜需求量的初步研究

采用四因子三水平的正交实验法,研究了河蟹大眼幼体至Ⅲ期幼蟹阶段对饲料中蛋白质、脂肪、矿物盐及复合维生素的适宜需求量.结果表明,影响河蟹大眼幼体至Ⅲ期幼蟹成活率的因素主次顺序为蛋白质＞矿物盐＞脂肪＞维生素,其最优水平分别为蛋白质35.50 %;矿物盐6 %;脂肪17.39 %;复合维生素1 %.河蟹从大眼幼体发育到Ⅲ期幼蟹,对饲料中蛋白质的适宜需要量有逐渐减少的趋势,即从45.52 %减至35.50 %;对矿物盐适宜添加量的要求有逐渐上升的趋势,即由2 %升至6 %;而对复合维生素适宜添加量的要求则有下降的趋势,即由3 %降至4 %;但对脂肪的适宜需要量一直是较稳定且较调换,即为17.39 %.     

转牛酪蛋白基因(α_(s1)—CaseinB)cDNA花生后代的种子蛋白质及叶片Gus酶活性检测

对花生转牛酪蛋白基因cDNA子二代 ,1 4株种子胚和子叶全蛋白的SDS—PAGE电泳分析表明 ,与对照比较 7株子二代中均有一条新的蛋白质带 ,并在子叶和胚中大量表达 .对 3株子二代及对照花生幼苗叶片的Gus酶活性检测表明 :1株 ( 2 0 1 1 )Gus酶活性较强     

营养元素调控热休克蛋白研究进展

热休克蛋白(Heat Shock Protein,HSP)是生物体在受热或其他不利环境因素刺激下应激合成的一组特殊蛋白质.HSP的生物学功能广泛,不仅表现在热应激条件下参与细胞的抗损伤、修复和热耐受过程,保护细胞生命活动,而且在蛋白质折叠、跨膜运输、细胞骨架及核骨架稳定等方面发挥重要作用.由于机体的营养状况与应激能力密切相关,本文主要综述了营养元素对HSP合成的调控作用.     

Evolutionary Mode of Metallothioneins Inferred from Cd-MT Genes of Tetrahymena

From Tetrahymena thermophila （strain BF5）, the coding region of Cd-MT gene was cloned and sequenced. and identified as MTT1 isoform. A serial duplicate structure is discovered in its amino acid sequence, which separates the coding region into three parts （Part 1：7-61; Part 2：64-118; Part 3：122-162）. The alignments among them and comparison with the corresponding parts of MT1 isoform suggest that MT1 and MTT1 isoforms both come from the same ancient gene that is homologous to Part 1, and Cd-MTs of Tetrahymena are aroused by such ancient gene duplication. The prediction of secondary structures and the analysis of the disulfide-bonding state of cysteine show that there are a lot of differences between MT1 and MTT1 isoforms, which maybe relate to their function mechanism.     

Prediction of β -turns using double BP network with novel coding schemes of amino acids

Protein structure prediction is one of the most important problems in structural biology. β-turns are always at the turn of a protein tertiary structure and thus β-turn’s prediction is a key step in tertiary structure prediction. There are some methods to predict β-turns based on machine learning techniques such as k-nearest method, neural networks and support vector machine. In this paper, we construct a classifier using double BP networks and put forward two novel methods to code amino acids in the second network. When trained and tested on different datasets, they achieve more accuracy than other coding methods.      

Albumin resuscitation protects against traumatic/hemorrhagic shock-induced lung apoptosis in rats

Objective： To determine the effects of albumin administration on lung injury and apoptosis in traumatic/hemorrhagic shock （T/HS） rats. Methods： Studies were performed on an in vivo model of spontaneously breathing rats with induced T/HS; the rats were subjected to femur fracture, ischemia for 30 min, and reperfusion for 20 min with Ringer＇s lactate solution （RS） or 5% （w/v） albumin （ALB）, and the left lower lobes of the lungs were resected. Results： Albumin administered during reperfusion markedly attenuated injury of the lung and decreased the concentration of lactic acid and the number of in situ TdT-mediated dUTP nick-end labelling （TUNEL）-positive cells. Moreover, immunohistochemistry performed 24 h after reperfusion revealed increases in the level of nuclear factor κB （NF-κB）, and phosphorylated p38 mitogen-activated protein kinase （MAPK） in the albumin-untreated group was down-regulated by albumin treatment when compared with the sham rats. Conclusion： Resuscitation with albumin attenuates tissue injury and inhibits T/HS-induced apoptosis in the lung via the p38 MAPK signal transduction pathway that functions to stimulate the activation of NF-κB.     

单细胞蛋白固态发酵系统的总氮平衡与功效评价

对ＳＳＦ法生产ＳＣＰ系统中的生物量，总糖、总氮等因素进行了动态分析。揭示了反应过程中总氮平衡的基本性质。讨论了同化作用，转化作用、分解作用等３种氮代谢反应方式以及物料收率降低引起蛋白含量升高的浓缩效应。同时分析了蛋白净增量和蛋白含量之间的相互关系。表明蛋白净增量是评价系统功效的合理指标。     

Structural view of cadherin-mediated cell-cell adhesion

Following the multiplication of biochemical, biophysical and structural studies describing cadherin molecules and their interactions, several ideas have emerged to explain the mechanisms of cadherin-mediated cell adhesion. Although different models were proposed for cadherin interactions, a consensus has come forth considering lateral dimerization of cadherins as being a central component of the cell-cell adhesion process. This review summarizes the recent development in structural studies of cadherins. Received 14 September 1998; received after revision 14 November 1998; accepted 16 November 1998     

非规则梁的弯曲刚度及其对钢框架柱计算长度的影响

针对钢结构非规则梁柱体系弹性分岔屈曲失稳的特点,认为普通钢框架考虑梁、柱线刚度比值关系确定刚架柱计算长度的方法仍适用于非规则框架中的框架柱。运用虚功原理推导了两种典型的非规则梁的弯曲刚度,并分析了其对钢框架柱计算长度的影响。