Regulation of cellular and molecular functions by protein phosphorylation

Modification of proteins by phosphorylation is the major general mechanism by which many cellular functions in eukaryotic cells such as cell division, malignant transformation, differentiation, signal transduction etc. are controlled by external physiological stimuli. At the molecular level protein phosphorylation-dephosphorylation can alter various properties of the substrate molecules such as enzymatic activity, sub-Cellular location, ligand binding, interaction with other proteins, DNA binding and some other functional properties. The changes in molecular properties of proteins brought about by protein phosphorylation play a critical role in regulating various cellular functions.     

人类新基因HBVDNAPTP1结合蛋白的生物信息学分析

[目的]应用生物信息学分析人类新基因乙型肝炎病毒(HBV)DNA聚合酶(Polym erase)反式调节蛋白(HBVDNAPTP1)结合蛋白(HBVDNAPTP1BP).[方法]利用生物信息学技术分析HBVDNAPTP1BP基因的染色体定位与组织表达,以及编码蛋白的化学物理性质与结构特征.[结果]HBVDNAPTP1BP基因染色体定位于1号染色体短臂3区5带1亚带,可在组织中低表达,但在多个组织中无表达.HBVD-NAPTP1BP的相对分子量为11 905.6,理论pI为7.72,不同条件下的消光系数为14 230 M-1cm-1或13 980M-1cm-1(280 nm),在体外哺乳动物网状细胞中的半寿期为30 h,并且无卷曲螺旋区域,但具有3个较强的疏水区域.HBVDNAPTP1BP无特殊二级结构,仅有1个蛋白激酶C磷酸化位点,不具有跨膜螺旋结构,无信号肽序列,定位于细胞核中.[结论]应用生物信息学对HBVDNAPTP1BP进行了分析,为进一步研究其生物学功能及其在乙型肝炎、肝细胞癌中的作用机制提供了依据和线索.     

Leading Change in Schools in Difficulty

School improvement is a complex undertaking for any school but for schools in challenging or difficult circumstances it presents extra problems. Not only do schools in challenging circumstances often face acute levels of socio-economic deprivation, but also, improvement or change efforts can be extremely fragile in these volatile school contexts. This article focuses upon the process of leading change in a group of schools in challenging circumstances in England. It draws upon empirical data and focuses particularly on the process of leading change in schools in difficulty by exploring three leadership themes. The article concludes by arguing that while the quality of leadership is undoubtedly important in these school contexts it is simply not sufficient to combat the stubborn relationship between social disadvantage and underachievement. This relationship is more likely to be broken through structural change and localised and community-based action rather than through the forces of standardization or accountability.     

Investigating Interaction Between Biochanin A and Human Serum Albumin by Multi-spectroscopic and Molecular Simulation Methods

Biochanin A(BCA), the most abundant isoflavone in chickpeas, presents a wide range of biological activities, such as hypolipidaemic, anti-oxidative, antiproliferative, and estrogen-like effects. We investigated the interaction between BCA and human serum albumin(HSA) via several techniques. UV–Vis absorption spectroscopy verified the conformational variation of HSA after BCA addition, and fluorescence spectroscopy revealed the relevant binding parameters. Circular dichroism spectroscopy was used to estimate the secondary structural changes of HSA with and without BCA. Molecular docking and dynamics simulations were then applied to study the characteristics of HSA with BCA. Energy decomposition analysis was used to prove that Trp214 in subdomain ⅡA of HSA is the most likely binding site of BCA. Van der Waals forces and hydrophobic interactions may play important roles during the binding process. All of our results showed that BCA presents significant binding affinity to HSA, thus confirming that the role of HSA has as an efficient transporter of biomolecules.     

活动革新信息技术教材——活动学习视野下信息技术教材的建构研究

《基础教育课程改革纲要(试行)》强调学生学习方式的转变,倡导自主学习、合作学习、探索学习等学习方式,学生的主体地位得到了极大关注。活动学习观视学习过程为一种特殊的活动过程,强调通过活动促进学生的主动发展,与基础教育改革所倡导的学习观不谋而合。以活动建构教材,将改变以往教材重"知识"轻发展、重"物"轻"人"的思想,以活动的形式变革信息技术教材。     

端粒酶和癌症的关系

端粒酶是由RNA和蛋白质亚基组成的一种逆转录酶,具有维持和控制端粒长度的功能,其活性变化与细胞癌变有密切关系,在癌细胞的恶性转化过程中,端粒酶的活化是一个重要步骤.抑制端粒酶活性在肿瘤治疗方面有着广阔的前景.     

Visualizing protein interactions and dynamics: evolving a visual language for molecular animation

Undergraduate biology education provides students with a number of learning challenges. Subject areas that are particularly difficult to understand include protein conformational change and stability, diffusion and random molecular motion, and molecular crowding. In this study, we examined the relative effectiveness of three-dimensional visualization techniques for learning about protein conformation and molecular motion in association with a ligand-receptor binding event. Increasingly complex versions of the same binding event were depicted in each of four animated treatments. Students (n = 131) were recruited from the undergraduate biology program at University of Toronto, Mississauga. Visualization media were developed in the Center for Molecular and Cellular Dynamics at Harvard Medical School. Stem cell factor ligand and cKit receptor tyrosine kinase were used as a classical example of a ligand-induced receptor dimerization and activation event. Each group completed a pretest, viewed one of four variants of the animation, and completed a posttest and, at 2 wk following the assessment, a delayed posttest. Overall, the most complex animation was the most effective at fostering students' understanding of the events depicted. These results suggest that, in select learning contexts, increasingly complex representations may be more desirable for conveying the dynamic nature of cell binding events.     

蛋白质的连接模型及机理研究

蛋白质是通过与其他蛋白质或生物分子的识别和连接来发挥功能的,阐明连接的驱动力及机理对理解蛋白质的功能发挥有很大帮助。文章对三种蛋白质连接的模型进行了描述和比较,对三种模型的驱动力和机理进行了研究,强调了蛋白质的连接是由热力学的熵焓互补平衡控制的过程。     

不同植被恢复模式对石漠化地区土壤多酚氧化酶的影响

多酚氧化酶是一种重要的土壤酶,对土壤环境的变化比较敏感,可作为土壤肥力变化和生态恢复的监测指标。为了深入了解桂西北石漠化地区生态恢复的现状,作者对广西宜州、平果等地进行了实地调查和取样,并从不同植被恢复的角度,对桂西北石漠化地区封山育林、吊丝竹(D.minor(McClure) Chia et H.L.Fung)、任豆(Zenia insignis Chun)等不同植被恢复模式样地的土壤多酚氧化酶及其与土壤有机质、全N、全P、有效N、有效P的相关性等方面进行了比较分析,试图了解不同植被恢复模式对石漠化地区生态恢复过程中土壤多酚氧化酶活性的影响,结果表明,以豆科植物为优势种或与豆科植物混交的植被恢复模式,其土壤多酚氧化酶活性较高,其他相关的土壤肥力测试指标也较高,因此,可以将之作为石漠化土地植被恢复的优化模式。     

儒家人文精神与当代道德建设

以儒家思想为代表的中国传统文化蕴藏着丰厚的人文精神,是当代道德建设的源头活水。面对科学技术迅猛发展和经济全球化带来的深刻变化,深入研究和开发儒学人文精神的思想资源,无论是在全球化进程中重建普世伦理,还是对于我国在社会体制转型期加强道德建设,都有重要而深远的意义。     

Activity and Behavioral Development in Stunted and Nonstunted Children and Response to Nutritional Supplementation

It is frequently assumed that undernutrition in young children leads to poor development through reduced activity. 3 groups of 26 1-year-old stunted children were studied: nutritional supplementation, supplementation with psychosocial stimulation, and controls. 26 nonstunted comparison children were also studied. Activity levels were measured by extensive observations in the homes, and development using 4 subscales of the Griffith's Mental Development Scales. Initially, stunted children were less active than nonstunted ones ( p < .01), but after 6 months they caught up regardless of treatment. The mental ages of the stunted children were lower than those of the nonstunted children initially, and improved with either treatment. Initially, activity levels made a significant contribution to the variance in the locomotor subscale only, but not 6 months later. Activity did not predict change in development over 6 or 12 months, nor did change in activity over 6 months predict change in development over 12 months.     

葡聚糖为筛分介质的无胶筛分毛细管电泳相互作用分析

本文利用线性高分子聚合物葡聚糖对大分子物质的筛分作用,通过改变大分子蛋白的电泳淌度,扩大迁移时间窗口,将无胶筛分毛细管电泳成功地运用于相互作用分析中,测定了伊贝沙坦与牛血清白蛋白之间的结合常数,建立了测定具有相似淌度的药物与蛋白之间结合常数的模型,进一步发展了毛细管电泳相互作用分析方法.     

切语初探

切语长期流传于民间,主要流传于盲人之中。它是一种秘密口语,其方法是将每个汉字的声母、韵母拆开,按一定规律分别再加上韵母和声母,由一个音节变成两个音节来说。切语有顺说、例说之别。顺说流传极广,例说知之者甚少,是一处独特的社会和口语现象。它传播过程中的盛衰,反映出深刻的社会原因。     

文化资本视角下的农村教师补充困境研究

对作为农村教师主要来源的农村籍大学生来说,当下农村社会的教育环境使得教师的文化资本日益异化于教师而存在。文凭资本一方面难以转换为经济资本和社会身份资本;另一方面,受结构性的社会、教育环境因素影响,文凭资本难以与工作的意义和价值建立联系,这是影响教师补充困境的深层原因。只要农村教育与以知识、技能为最主要凝结物的文化资本的弱势地位得不到改变,农村教师在入职、工作状态上的不利局面就很难得以根治。     

Identification of novel catalytic features of endo-β-1,4-glucanase produced by mulberry longicorn beetle Apriona germari

Mulberry longicorn beetle, Apriona germari, has been reported to produce two endo-β-l,4-glucanases or AgEGases (accession Nos. Q6SS52 and Q5XQD1). AgEGase sequence contains catalytic motif (amino acid residues 37～48), which is the characteristic of family Glycohydrolase 45 and is identified as the substrate binding site. The application of bioinformatics approaches includes sequence analysis, structural modeling and inhibitor docking to relate the structure and function of AgEGases.We have dissected the sequence and structure of AgEGase catalytic motif and compared it with crystal structure of Humicola insolens endoglucanases Ⅴ. The results show an involvement of sulfur containing amino acid residues in the active site of the enzyme. Cys residues and position of disulfide bonds are highly conserved between the two structures of endoglucanases of A.germari. Surface calculation of AgEGase structure in the absence of Cys residues reveals greater accessibility of the catalytic site to the substrate involving Asp42, a highly conserved residue. For the inhibition study, tannin-based structure was docked into the catalytic site of AgEGase using ArgusLab 4.0 and it resulted in a stable complex formation. It is suggested that the inhibition could occur through formation of a stable transition state analog-enzyme complex with the tannin-based inhibitor, as observed with other insect cellulases in our laboratory.     

Parents’ past experiences as a mediational tool for understanding their child’s current mathematical learning

This article explores the ways in which parents use their own past experiences as a mediational tool for understanding their child’s current school learning. Following a sociocultural approach parents’ past experiences were examined drawing on the notions of (1) heterochronicity, which looks at the partially overlapping histories of the individual and society and (2) prolepsis whereby the imagined future mediates and constrains the world of the present. The analysis draws on 22 interviews with parents whose children were from three primary multiethnic schools in a town in the Southeast of England. The findings brought to light the means by which parents can either intentionally or unintentionally use the past to inform their current representations and practices. Thus at times they use their past experiences to mediate internalisation (reproduction of the experience), at other times they use them to promote externalisation (change brought about by the experience). It is within this process that parents projected a future ideal for their child, which was either congruent or discordant with their own past.     

HTML中JavaScript的一些应用探讨

JavaScript是一种描述性的脚本语言 (ScriptLanguage) ,它可以非常自由地被嵌入到HTML (HypertextMarkupLanguage)的文件之中。使用JavaScript就是对网页浏览者当前所触发的事件进行处理或对网页进行初始化工作。这是事先在网页中编写好代码 (或叫做“脚本”) ,然后此代码伴随Html文件一起传送到客户端的浏览器上 ,由浏览器对这些代码进行解释执行 ,而其执行期间并没有使用服务器处理 ,从而减轻了服务器的负担。作者对JavaScript的应用作了一些讨论。     

Computational prediction of cleavage using proteasomal in vitro digestion and MHC I ligand data

Proteasomes are responsible for the production of the majority of cytotoxic T lymphocyte (CTL) epitopes. Hence, it is important to identify correctly which peptides will be generated by proteasomes from an unknown protein. However, the pool of proteasome cleavage data used in the prediction algorithms, whether from major histocompatibility complex (MHC) I ligand or in vitro digestion data, is not identical to in vivo proteasomal digestion products. Therefore, the accuracy and reliability of these models still need to be improved. In this paper, three types of proteasomal cleavage data, constitutive proteasome (cCP), immunoproteasome (iCP) in vitro cleavage, and MHC I ligand data, were used for training cleave-site predictive methods based on the kernel-function stabilized matrix method (KSMM). The predictive accuracies of the KSMM+pair coefficients were 75.0%, 72.3%, and 83.1% for cCP, iCP, and MHC I ligand data, respectively, which were comparable to the results from support vector machine (SVM). The three proteasomal cleavage methods were combined in turn with MHC I-peptide binding predictions to model MHC I-peptide processing and the presentation pathway. These integrations markedly improved MHC I peptide identification, increasing area under the receiver operator characteristics (ROC) curve (AUC) values from 0.82 to 0.91. The results suggested that both MHC I ligand and proteasomal in vitro degradation data can give an exact simulation of in vivo processed digestion. The information extracted from cCP and iCP in vitro cleavage data demonstrated that both cCP and iCP are selective in their usage of peptide bonds for cleavage.     

微透析法研究金属离子镉与人血清蛋白的相互作用

本文建立了一种新的方法──微透析法用于研究金属离子铺与人血清蛋白（Ｈｕｍａｎ Ｓｅｒｕｍ Ａｌｂｕｍｉｎ，简称ＨＳＡ）的相互作用．测定了金属离子Ｃｄ２＋与ＨＳＡ之间的结合位点数为１．８１和结合常数３．５５×１０５Ｍ－１微透析回收率Ｃｄ２＋为５８．３６％（Ｒ．Ｓ．Ｄ２．１％，ｎ＝６）．通过各种离子之间的竞争结合建立了通用的判定金属离子的共同结合位点及相对结合强度的方法．证明在ＨＳＡ上Ｃｄ２＋和Ｚｎ２＋有共同的第一结合位点，它们在ＨＳＡ上有一多元素的共同结合位点．应用本实验方法可以节约蛋白３／４以上，并具有精确、快速、方便等特点．