细胞凋亡的信号传导通路

本文从细胞凋亡的基本分子机制、凋亡信号的跨膜传导和细胞内凋亡信号传导三个方面综述了细胞凋亡的细胞外和细胞内的信号传导通路。     

线粒体相关物质与细胞凋亡

“凋亡”一词源于希腊文,意为“花瓣或树叶的枯落”,是1972年由病理学家Kerr等首先提出的一个不同于坏死的死亡概念,指由体内外因素触发细胞内预存的死亡程序而导致的程序性细胞死亡（programmed cell death,PCD）。凋亡细胞中可出现各种生化改变如内源性核酸内切酶激活、     

细胞坏死及细胞程序性死亡和细胞凋亡

细胞死亡是细胞生物学研究的基本问题,细胞死亡机理的研究对多种疾病的治疗及探索衰老原因等方面有很重要的意义。本简要综述了当前对细胞死亡方式的基本认识及研究细胞死亡的意义和前景。     

细胞凋亡与细胞死亡及细胞程序性死亡的区别

细胞凋亡 (Ａｐｏｐｔｏｓｉｓ)概念是 1972年由美国病理学家Ｋｅｒｒ等人首次提出的。近十几年来已成为生物学界研究的热点问题之一。在讨论该问题时 ,往往把它和细胞程序性死亡 (Ｐｒｏｇｒａｍｍｅｄｃｅｌｌｄｅａｔｈ ,ＰＣＤ)、细胞坏死性死亡联系在一起 ,有时导致几个概念的混淆。本文简要介绍细胞凋亡与细胞程序性死亡及细胞死亡的区别。1　细胞凋亡和细胞死亡细胞凋亡 (Ａｐｏｐｔｏｓｉｓ)是生物界广泛存在的一种现象 ,与其它的生命现象一样具有同等重要的生理学或病理学意义。尽管其最终结果也是导致细胞死亡 ,但其诱导因素、发…     

细胞凋亡的调控因素

细胞凋亡是细胞与生俱来的一种机制，是最常见的细胞生理性死亡形式。高浓度的活性氧是启动细胞凋亡的信号。它是在电子传给末端氧化酶之前漏出呼吸链与氧反应生成的。活性氧水平的升高使线粒体上非特异性的通透性转运孔道开放，于是原来位于线粒体膜间隙的某些与凋亡有关的活性物质释放到细胞液中，激活胱天蛋白酶，引起细胞凋亡。位于凋亡后期的效应因子也可被不同的凋亡前期信使分子所激活，而IAP蛋白则能通过直接抑制胱天蛋白酶家族蛋白的活化过程而抑制凋亡的发生。     

线粒体与细胞凋亡及临床疾病

线粒体是哺乳动物细胞内唯一含有核外遗传物质的细胞器，由于其自身的特征及其所处的环境，使线粒体DNA(mtDNA)较核DNA(nDNA)更易损伤或突变：通过线粒体外膜释放凋亡活性物质和通透性转换孔开放，可促进细胞凋亡；mtDNA的损伤和突变与人类衰老、神经退行性疾病、糖尿病及肿瘤等疾病的发生均有关系。     

线粒体与细胞凋亡

细胞凋亡又称细胞程序性死亡 ,是各种内外信号激活细胞死亡程序后发生的一种自杀行为 ,是生物体维持正常生长发育的自稳机制。通过正常的细胞凋亡可清除体内衰老的、磨损的或已完成功能的细胞 ,如胚胎细胞、胸腺细胞、蝌蚪变态时尾巴细胞等 ;并能清除具潜在危险的畸变细胞 ,如自身反应性淋巴细胞、突变细胞、肿瘤细胞等。体内自然凋亡途径若发生紊乱 ,可导致发育异常和一些疾病 ,如细胞凋亡过低而导致的癌症、细胞凋亡过渡导致的神经变性紊乱、局部缺血等。1　多种因素参与细胞凋亡细胞凋亡是一个复杂的过程 ,当细胞因子耗尽、基因毒物伤害…     

线粒体与细胞凋亡

随着近年来对线粒体研究的深入，发现线粒体与细胞凋亡有着密切的关系。它通过释放细胞色素C、凋亡诱导因子AIF，或者通过产生氧自由基等多种途径导致细胞凋亡。     

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。     

线粒体与细胞凋亡

细胞编程性死亡即细胞凋亡是健康个体中的一个正常过程．近年来发现细胞凋亡与线粒体的结构与功能有着密切的关系．线粒体氧化磷酸化过程中生成活性氧，使线粒体上PT孔道开放，削弱了线粒体膜两侧的质子梯度，导致ATP合成下降；同时向细胞液释放了与凋亡有关的活性物质，激活Caspases，引起细胞凋亡．     

CD33分子信号传递及其功能的研究进展

CD33分子为一种跨膜受体,主要存在于血液、骨髓和淋巴细胞中.它属于免疫球蛋白超家族成员,并且是能够结合唾液酸的免疫球蛋白样的凝集素家族成员.在这一膜受体内部存在免疫受体酪氨酸抑制基序(ITIM).由于ITIM能够特异性的与酪氨酸磷酸酶shp-1和shp-2结合并向胞内传递抑制性信号,从而达到抑制细胞活性的目的,所以CD33分子主要在临床上作为一种靶位点用于急性骨髓系白血病(AML)的治疗.     

Effect of resveratrol treatment on apoptosis and apoptotic pathways during boar semen freezing

Resveratrol (3,5,4'-trihydroxystilbene, RSV) has been widely used in mammalian cells, but whether it can be used during freezing boar semen is still unknown. The effects of RSV treatment during boar semen freezing on its anti-freezing ability, apoptosis, and possible apoptotic pathways were observed in this study. Sperm motility, mitochondrial membrane potential (ΔΨm), adenosine triphosphate (ATP) content, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)-positive apoptotic state, and messenger RNA (mRNA) expression levels of apoptotic genes involved in different apoptotic pathways after freezing with or without RSV treatment were tested. The results showed that: (1) Compared with fresh sperm, the motility, normal acrosome rate, and plasma membrane integrity rate of frozen boar sperm decreased significantly (P<0.05), and RSV did not significantly increase the sperm motility (0.44 vs. 0.40, P>0.05), but it did significantly improve the normal acrosome rate (57.65% vs. 47.00%, P<0.05) and plasma membrane integrity rate (46.67% vs. 38.85%, P<0.05). (2) After freezing, most boar sperm showed low mitochondrial ΔΨm. RSV treatment could increase the rate of high mitochondrial ΔΨm of boar sperm. (3) RSV treatment significantly decreased reactive oxygen species (ROS) levels (58.65% vs. 88.41%, P<0.05) and increased the ATP content (0.49 μmol/L vs. 0.25 μmol/L, P<0.05) of boar sperm during freezing. (4) The apoptotic rate of the freezing group (80.41%) with TUNEL detection increased significantly compared to the fresh group (9.70%, P<0.05), and RSV treatment greatly decreased the apoptotic rate (68.32%, P<0.05). (5) Real-time polymerase chain reaction (RT-PCR) showed that not only the genes from the death receptor-mediated apoptotic pathway (tumor necrosis factor-α (TNF-α), Fas ligand (FasL), and Caspase-8), but also the genes from the mitochondria-mediated apoptotic pathway (manganese superoxide dismutase (MnSOD), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and Caspase-9) were both significantly changed after freezing. RSV treatment during freezing greatly changed their expression levels. Although RSV treatment during boar semen freezing did not significantly increase motility after thawing, it still played an efficient antioxidant role, which could enhance the mitochondrial function and decrease the apoptotic level induced by both the death receptor- and mitochondria-mediated apoptotic pathways.

     

Toxoplasma gondii infection induces cell apoptosis via multiple pathways revealed by transcriptome analysis

Journal of Zhejiang University-SCIENCE B - Toxoplasma gondii is a worldwide parasite that can infect almost all kinds of mammals and cause fatal toxoplasmosis in immunocompromised patients....     

Ineffective pathways and the price of conjecture

The inclusion of children with special educational needs into mainstream schools needs effort and cooperation by all those involved. Both educators and medical professions need to be skilled in identifying and supporting neurodiversity. This study explores the cross-professional understanding and support of four of the most prevalent neurodiversities: autism spectrum condition, attention deficit hyperactivity disorder, developmental coordination disorder and dyslexia, to evaluate the efficiency of the diagnostic pathway and the subsequent support. Questionnaires were distributed throughout a number of training events for medical and educational practitioners asking what a condition was, and how it could be supported. Using a thematic analysis, data from 189 responses were examined and cross-referenced with diagnostic criteria, in addition to identifying the overarching themes of support. Results show a serious gap in awareness and knowledge of neurodiversity in both medical and educational sectors, followed by a cacophony of intervention, breaking the pathway for diagnosis before it begins and ultimately failing children and their families.     

Estimation of relative elasticities of substitution and relative compensation for part-time faculty

Part-time workers have become a visible and noticeably larger component of the labor force in recent years. From an economic perspective, relative compensation changes may be a major factor determining the growth of the part-time sector. Yet, surprisingly little has been done to explore the effects of these changes on the relative rates of growth in part- and full-time labor markets. In part, this is because of the difficulty in obtaining data on the compensation paid to part-timers. In this paper, we suggest a methodology for deriving such data through statistical estimation and use survey data of over 2,100 institutions of higher education, conducted by the American Association of University Professors.     

阶跃信号在信号处理中的开拓功能

利用广义函数的方法,修正了指数信号和指数衰减的Fourier变换公式,探讨了阶跃信号在信号处理方法——Fourier变换中的开拓功能,得出了在Laplace变换中通过解析开拓才能得到的相同结论,从而为进一步改变人们在Fourier变换认识方面的偏见提供了理论依据。     

信号与系统教学浅探

信号与系统是电子信息类专业学生在大学阶段的基础专业理论课。这门课主要学习如何使用科学的方法描述生活中的信息以及信号的分析和处理过程。课程内容是学生从中学阶段的被动式学习过渡到高等教育阶段的主动式学习的关键节点,包含了培养学生进行更高层次的科学理论学习和培养具备科学理论创新能力的基础理论知识。然而,在这门课的教和学的过程中一直存在很多的问题,使得很多大学生没有及时掌握这门课的内容,为后续的知识学习造成了困难。为了使学生能够快速地接受和掌握该门课程内容,文章从信号与系统课程内容特点分析和探讨这门课的一些教学思路。     

氧化性、还原性相对强弱的判断

根据氧化、还原反应的特点，可用多种不同形式进行比较，以达到判断物质的氧化、还原性强弱的目的。     

论第三信号

第一信号是具体可感物体产生的刺激。第二信号是第一信号的信号,是由语言、文字、符号、密码等构成,是具体可感刺激物的代表。人类有了第二信号这个得力工具以后,使科学技术、人类文明获得了有效的记录、传承和发展,使人类大大超越了其他高等动物。第三信号是第二信号的代表,第三信号将大大提高信息传播的速度,压缩第二信号的符号数量,扩充信息存储的空间,提高工作效率。探讨了三种信号间的关系,探讨了创制第三信号的策略及第三信号的发展趋势。指出第三信号的创制,让须符合简约、明了、形象、易识、易写、高涵盖的要求。