反义bcl-2逆转录病毒表达载体的构建

凋亡是一种不同于坏死且受基因控制的主动性细胞自我消亡过程,亦是许多抗癌药物作用的主要机理之一。Bcl-2是一种凋亡负控制的重要基因,其蛋白产物能抑制细胞的凋亡或程序性细胞死亡过程。我们构建了反义bcl-2逆转录病毒表达载体导入多发性骨髓瘤细胞株来调节Bcl-2基因表达,从而诱导细胞凋亡或增加细胞对凋亡诱导剂的敏感性,来探讨与多发些骨髓瘤的关系。     

B细胞淋巴瘤/白血病-2蛋白家族与细胞凋亡

近年来 ,细胞凋亡已成为生物医学研究领域中的一个热点 ,细胞凋亡过程复杂 ,有许多因子参与其中 ,Bcl- 2蛋白家族是细胞凋亡研究中最受关注的蛋白类群 ,它是细胞凋亡信号转导的主要调节物 ,在细胞凋亡过程中发挥重要的作用。B细胞淋巴瘤 /白血病 - 2 (B -celllymphoma/leukemia- 2 ,Bcl- 2 )基因是第一个被发现的能抑制多种细胞凋亡的原癌基因 ,它是Bcl- 2蛋白家族基因的原型。Bcl- 2基因最初是从人的滤泡性B细胞淋巴瘤中分离出来的 ,通常它定位于人的第 18号染色体。Bcl - 2蛋白由 2 39个氨基酸组成 ,分子量为 2 5～2 6KD。大多数Bcl-…     

细胞凋亡的形态特征与分子机制概述

细胞凋亡是细胞的主动死亡过程,涉及一系列基因的表达和调控。在细胞的正常发育过程中,约有半数细胞通过凋亡途径被清除。凋亡蛋白酶在细胞凋亡中具有不同功能,可以将其分为两类：第一类直接对细胞的功能蛋白进行水解并导致细胞解体,称为效应凋亡蛋白酶;第二类参与上游事件的调节并启动蛋白酶解级联反应,称为启动凋亡蛋白酶。在细胞凋亡过程中,作为传感器的细胞表面凋亡受体接受由凋亡配体发出的凋亡信号,并传递到胞内,激活凋亡蛋白酶家族成员,借助凋亡信号结构域相继激活凋亡蛋白酶,进而降解特定的靶蛋白,最终导致细胞死亡。     

运动与细胞凋亡

细胞凋亡是由基因调控的细胞死亡过程,它对于多细胞生物的生存和发展以及维持其自身的稳定有极其重要的作用。近几年来,细胞凋亡已成为运动医学界研究的热点。本文通过查阅资料,对各种实验模型中运动或类似运动而引起的细胞凋亡进行总结,试图从中发现运动性与细胞凋亡的关系,以便为运动性疲劳的判断和恢复,运动损伤的尽快修复提供一定的指导。     

胰岛β细胞凋亡与一氧化氮

胰岛β细胞对各种促凋亡刺激非常敏感,β细胞凋亡在1、2型糖尿病的发病过程中起了重要作用.近年研究发现,β细胞凋亡过程涉及诸多方面,目前人们的研究主要集中在自身免疫、Fas/FasL系统、Caspase、细胞因子、过氧化等方面.一氧化氮作为一个新发现的免疫因子,参与多种因素诱导的β细胞凋亡的过程,其具体作用机制还不十分清楚.     

运动性疲劳与肌细胞凋亡的研究

细胞凋亡是由基因控制的细胞死亡过程,它对于多细胞生物的生存和发展以及维护其自身的稳定有极其重要的作用.从细胞凋亡的机制及运动性疲劳与凋亡的关系入手.综述了国内外在这方面的研究进展,以便为寻找新的运动性疲劳的判断和消除手段,提供一些新的思路.     

大强度运动过程中的细胞凋亡与基因调控

探讨运动诱导细胞凋亡的基因调控机制。运用文献综述的方法对这一涉及基因调控的分子事件进行探讨。运动训练可引起多种组织细胞的凋亡基因表达发生变化,这一变化可引起细胞发生凋亡和抑制凋亡的发生。同时,细胞凋亡是一个复杂的细胞变化过程,还有多种因素参与了这一过程。     

CASPASE与细胞凋亡

细胞凋亡是细胞生命的基本特征之一,凋亡过程中可分为启动期、效应期和降解期。其效应期中Caspase激活是一重要生化事件,本文就Caspase酶的家族成员、作用底物、激活及调控等作一简单探讨。     

放线菌素D诱导HeLa细胞凋亡形态学观察

凋亡是细胞在一定的生理或者病理条件下按照自身的程序结束其生存，是由基因决定的自动结束生命的主动过程，是受到严格的遗传机制决定的程序性调控。细胞凋亡对于多细胞生物个体的胚胎发育、维持器官组织细胞数目相对平衡、自我平衡的保护以及抵御外界因素的干扰有着重要意义。阐述观察放线菌素D诱导HeLa细胞凋亡形态的方法和观察结果，以及对结果的分析讨论。     

浅谈细胞凋亡

细胞凋亡是指细胞接受某种信号或某种因素刺激后为了维持自身内环境稳定而发生的一种主动性消亡过程。近年来的研究表明细胞凋亡的方式在机体的许多生理病理过程中都起作用，因此细胞凋亡的研究正成为一个国际上研究的新热点。     

基于密码子偏好特征的原核基因组多拷贝基因序列分析

基因重复是普遍存在的现象,与基因组进化密切相关,是基因组和遗传系统分化的重要推动力.目前针对原核基因组中蛋白质编码基因序列中的重复基因的系统研究还很少.本文以四种具有不同GC%含量的原核生物基因组为研究对象,用CodonW软件对各基因组中完全相同的功能基因的密码子使用偏好进行分析,用CD-hit软件对各基因组中以80%为阈值的重复蛋白编码基因进行分析.结果表明四个基因组的蛋白编码基因中普遍存在基因重复序列,其比例占到2.77%~7.03%.对序列完全相同的功能已知基因的分析表明其序列长度分布在50bp到1000bp左右的范围,多数长度在500bp以下;功能分析表明所研究基因组中大部分重复基因与转座酶有关,还有少量的编码转移酶、水解酶、跨膜蛋白、阻遏蛋白等.对各基因组中重复基因中序列完全相同的基因的密码子偏好性分析表明这些多拷贝基因坐落在基因组中某一特定区域并集中分布,展现出明显的共性特征.本文的尝试性工作将为今后原核基因组研究提供新思路.     

Generalist Genes: Genetic Links Between Brain, Mind, and Education

ABSTRACT— Genetics contributes importantly to learning abilities and disabilities—not just to reading, the target of most genetic research, but also to mathematics and other academic areas as well. One of the most important recent findings from quantitative genetic research such as twin studies is that the same set of genes is largely responsible for genetic influence across these domains. We call these "generalist genes" to highlight their pervasive influence. In other words, most genes found to be associated with a particular learning ability or disability (such as reading) will also be associated with other learning abilities and disabilities (such as mathematics). Moreover, some generalist genes for learning abilities and disabilities are even more general in their effect, encompassing other cognitive abilities such as memory and spatial ability. When these generalist genes are identified, they will greatly accelerate research on general mechanisms at all levels of analysis from genes to brain to behavior.     

Reading and Generalist Genes

ABSTRACT— Twin-study research suggests that many (but not all) of the same genes contribute to genetic influence on diverse learning abilities and disabilities, a hypothesis called generalist genes . This generalist genes hypothesis was tested using a set of 10 DNA markers (single nucleotide polymorphisms [SNPs]) found to be associated with early reading ability in a study of 4,258 7-year-old children that screened 100,000 SNPs. Using the same sample, we show that this early reading SNP set also correlates with other aspects of literacy, components of mathematics, and more general cognitive abilities. These results provide support for the generalist genes hypothesis. Although the effect size of the current SNP set is small, such SNP sets could eventually be used to predict genetic risk for learning disabilities as well as to prescribe genetically tailored intervention and prevention programs.     

第17号染色体短臂杂合性缺失与肿瘤的研究进展

抑癌基因是人类正常细胞中所具有的一类基因，对细胞的增殖分化有调节作用。染色体体臂上某一区域非随机杂合性缺失导致抑癌基因的丧失，从而促使肿瘤发生。本文总结了第17号染色体短臂(17p)杂合性缺失与肿瘤发生关系的研究进展，该研究不仅为我们定位新的抑癌基因提供了基础，为肿瘤的预防、早期发现和诊断提供了依据，同时也使我们能更好理解肿瘤的分子进展。     

Fitting into Our Genes: Evolutionary Theory of the Health Benefits of Physical Activity

ABSTRACT

There is ample evidence that regular physical activity can prevent or delay a large number of chronic health conditions in humans, and the evolutionary theory of the health benefits of physical activity may provide insight into this phenomenon. Because the physical activity of tracking/hunting game and constantly searching for other food, water, and resources was necessary for the survival of our Paleolithic (hunter-gatherer) ancestors, evolutionary selective pressure ensured the propagation of genes that optimally supported acute and repeated bouts of physical activity. In contrast, genes that did not optimally respond to physical activity were lost to natural selection over millions of years. The Neolithic (agrarian) descendants of the hunter-gatherers also led lives of high physical exertion, to which their inherited genes (programmed to expect physical activity) responded in a healthy fashion. Unfortunately, modern sedentary behavior promotes the unhealthy expression of physical activity-responsive genes, thus precipitating chronic disease and premature mortality. As the modern-day chronic disease epidemic expands seemingly unchecked, it is increasingly important to reintroduce widespread physical activity to a species genetically pre-programmed to thrive on it, thus fitting into our genes.     

Analysis of the 3' ends of tRNA as the cause of insertion sites of foreign DNA in Prochlorococcus

The purpose of this study was to investigate the characteristics of transfer RNA(tRNA) responsible for the association between tRNA genes and genes of apparently foreign origin(genomic islands) in five high-light adapted Prochlorococcus strains.Both bidirectional best BLASTP(basic local alignment search tool for proteins) search and the conservation of gene order against each other were utilized to identify genomic islands,and 7 genomic islands were found to be immediately adjacent to tRNAs in Prochlorococcus marinus AS9601,11 in P.marinus MIT9515,8 in P.marinus MED4,6 in P.marinus MIT9301,and 6 in P.marinus MIT9312.Monte Carlo simulation showed that tRNA genes are hotspots for the integration of genomic islands in Prochlorococcus strains.The tRNA genes associated with genomic islands showed the following characteristics:(1) the association was biased towards a specific subset of all iso-accepting tRNA genes;(2) the codon usages of genes within genomic islands appear to be unrelated to the codons recognized by associated tRNAs;and,(3) the majority of the 3' ends of associated tRNAs lack CCA ends.These findings contradict previous hypotheses concerning the molecular basis for the frequent use of tRNA as the insertion site for foreign genetic materials.The analysis of a genomic island associated with a tRNA-Asn gene in P.marinus MIT9301 suggests that foreign genetic material is inserted into the host genomes by means of site-specific recombination,with the 3' end of the tRNA as the target,and during the process,a direct repeat of the 3' end sequence of a boundary tRNA(namely,a scar from the process of insertion) is formed elsewhere in the genomic island.Through the analysis of the sequences of these targets,it can be concluded that a region characterized by both high GC content and a palindromic structure is the preferred insertion site.     

How to Understand the Gene in the Twenty-First Century?

It is widely acknowledged in the literature on philosophy of biology and, more recently, among biologists themselves that the gene concept is currently in crisis. This crisis concerns the so-called “classical molecular concept”, according to which a gene is a DNA segment encoding one functional product, which can be either a RNA molecule or a polypeptide. In this paper, we first describe three categories of anomalies that challenge this way of understanding genes. Then, we discuss proposals for revising the gene concept so as to accommodate the increasingly known complexity of genomic architecture and dynamics. Our intention is to provide an informative overview of recent proposals concerning how we should conceive of genes, which are probably not very familiar to many science educators and teachers, but can bring relevant contributions to genetics teaching, in particular, to a more critical treatment of genes and their role in living systems.