50 ku keratin-like protein and -microtublin coexist in higher plant cells

IF-like proteins have been obtained from suspension cells of Nicotiana tabacum by selective extraction. Western blot analysis shows that the major components of IF-like proteins are 6 keratin-like proteins of 64, 58, 55, 54, 50 and 45 ku. Specially the 50 ku protein also reacts with polyantibody against microtublin. Two-dimensional gel electrophoresis shows that the 50 ku protein is composed of two different proteins and their amino acid sequences have been determined. Part of the sequence of one protein is identical to that of -microtublin and the other protein's sequence has no significant homologue, which should be a new sequence-unknown protein. These results suggest that 50 ku keratin-like protein and -microtublin coexist in higher plant cells, and that may lead to the phenomenon of co-distribution of IF and microtuble in plant cells.     

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     

不同生境拟穴青蟹螯足肌肉营养品质评价

为探究不同生境、不同食物源拟穴青蟹(Scylla paramamosain，以下简称“青蟹”)的螯足肌肉营养品质的差异，本研究通过采集5种不同生境青蟹(生态青蟹、藤壶青蟹、天然青蟹、混饵养殖青蟹和单饵养殖青蟹)，取其螯足肌肉组织测定基本营养成分、氨基酸含量和脂肪酸含量，并通过必需氨基酸指数(EAAI)、支链氨基酸与芳香族氨基酸含量的比值(F)进行分析。结果表明，生态青蟹的蛋白质含量略高于天然青蟹和混饵养殖青蟹；藤壶青蟹的含水率最高，蛋白质含量最低；5种青蟹的粗脂肪和总灰分含量差异均不显著。生态青蟹的总氨基酸含量和必需氨基酸含量均最高，藤壶青蟹的鲜味氨基酸含量最高；藤壶青蟹的EAAI (112.48)和F (2.36)最高，生态青蟹的EAAI (95.35)和F (1.95)分别与天然青蟹的EAAI (96.15)和F (1.90)基本一致；单饵养殖青蟹的EAAI (72.00)和F (1.53)均最低。生态青蟹的单不饱和脂肪酸、多不饱和脂肪酸含量最高，其二十二碳五烯酸+二十二碳六烯酸(EPA+DHA)显著高于天然青蟹，且部分不饱和脂肪酸含量显著高于天然青蟹、混饵养殖青蟹和单饵养殖青蟹。从蛋白质、总氨基酸、必需氨基酸和不饱和脂肪酸的含量来看，生态青蟹的含量最高；从EAAI和F来看，藤壶青蟹的评价最高，说明2种红树林生态修复产出的青蟹品质较好。