细胞器与细胞凋亡

细胞凋亡是由基因控制的有序生理过程,细胞内各组分在这一过程中相互协调,组成了精细的调控系统。除细胞核外,线粒体是近年发现与凋亡密切相关的细胞器,它经多种因子诱发可以释放细胞色素c等因子参与到凋亡途径中。进一步的研究发现,在一定条件下,内质网、溶酶体等也与凋亡活动有关。这些细胞器在细胞凋亡中的作用及其机制是目前的研究热点。     

Tunicamycin and brefeldin a induce in plant cells a programmed cell death showing apoptotic features

Summary The recent identification ofDAD (defender against apoptotic death) gene in plants suggests that the N-linked glycosylation of proteins could be an important control point of plant programmed cell death. In this paper we describe the effects of Tunicamycin, an inhibitor of N-linked protein glycosylation, and Brefeldin A, an inhibitor of protein trafficking from the Golgi apparatus, on sycamore (Acer pseudoplatanus L.) cell cultures. These two chemicals proved able to induce a strong acceleration of the cell death; changes in cell and nucleus morphology; an increase in DNA fragmentation, detectable by a specific immunological reaction; and the presence of oligonucleosomal-size fragments (laddering) in DNA gel electrophoresis. Moreover, Brefeldin A, but not Tunicamycin, strongly stimulated the production of hydrogen peroxide. These results indicate that also in plants chemicals interfering with the activities of endoplasmic reticulum and of Golgi apparatus strongly induce a form of programmed cell death showing apoptotic features.     

蛇毒与细胞凋亡

简要介绍了细胞凋亡的形态学变化和生物化学等特性,及其主要的定性、定量检测方法,综述了蛇毒在细胞凋亡和肿瘤研究中的发展概况和国外最新进展。     

Possible involvement of the mitochondrial alternative pathway in ethylene-induced apoptosis in tomato protoplasts

In this study, a monoclonal antibody to the terminal oxidase of the alternative pathway from Sauromatum guttatum was used to detect the expression of alternative oxidase (AOX) protein in tomato mitochondria. The results show that there was an obvious correlation between the ethylene-induced apoptosis and the levels of AOX protein in tomato cells undergoing ethylene-induced apoptosis. In addition, when tomato protoplasts were preincubated with 2 mM salicylhydroxamic acid (SHAM), an inhibitor of the alternative pathway, before their exposure to ethylene, the TUNEL positive reaction and DNA fragmentation were obviously accelerated. We suggest that AOX may play an important role in protecting tomato protoplasts against ethylene-induced apoptosis.     

不同月龄大鼠空肠粘膜上皮细胞的形态、增殖及凋亡

为研究雄性大鼠空肠在发生、发育和衰老过程中上皮细胞增殖与凋亡形态学的变化,本实验采用增殖细胞核抗原(PCNA)免疫细胞化学染色、原位末端标记(TUNEL)法检测了不同生长发育阶段SD大鼠空肠绒毛粘膜上皮及小肠腺上皮的细胞增殖、凋亡的变化情况,并统计测量了不同发育阶段大鼠空肠绒毛的高度、肌层厚度及绒毛杯形细胞、肠腺杯形细胞的数量变化。观察到大鼠空肠肠腺隐窝增殖细胞的阳性着色表达从出生后开始增强,到3月龄时达最高峰,12月龄时增殖细胞阳性染色又减弱;凋亡细胞主要分布于固有层,凋亡阳性细胞数在3月龄最多;大鼠空肠绒毛的高度从初生后开始增加,到3月龄达顶峰,而后开始变矮;空肠肌层在3周龄、12月龄较厚;杯形细胞数量于生后3周迅速增长,不同发育阶段的大鼠空肠肠腺隐窝的杯形细胞数量与年龄呈正相关。     

HSF2 mRNA在热应激和大剂量11酸睾酮诱导恒河猴生精细胞凋亡中的表达变化

为了探讨HSF2 mRNA在热应激和超生理剂量睾酮诱导恒河猴生精细胞凋亡中的表达变化,我们建立了手术诱导单侧隐睾和注射大剂量11酸睾酮（TU）恒河猴动物模型,应用3′末端标记分析（TUNEL）和原位杂交方法,检测睾丸细胞的凋亡信号和HSF2的表达变化。TUNEL结果显示热应激和超生理剂量睾酮能够诱导生精细胞出现凋亡信号,它分别于处理后第5天和第30天达到最强,表明热应激和睾酮干扰精子发生可能是通过生精细胞凋亡的方式来实现的。HSF2 mRNA水平在生精细胞凋亡早期（凋亡信号达到最强以前）略有降低,而在凋亡高峰期之后其表达急剧下降。Hsf2基因与我们以前研究的Hsp70-2基因的表达具有时间上的相关性,表明HSF2蛋白可能调控Hsp70-2基因的表达,而且HSF2可能通过多种方式影响精子的发生以及抑制生精细胞的凋亡。     

Sequence and functional similarities between pro-apoptotic Bid and plant lipid transfer proteins

Pro-apoptotic proteins of the Bcl-2 family are known to act on mitochondria and facilitate the release of cytochrome c, but the biochemical mechanism of this action is unknown. Association with mitochondrial membranes is likely to be important in determining the capacity of releasing cytochrome c. The present work provides new evidence suggesting that some pro-apoptotic proteins like Bid have an intrinsic capacity of binding and exchanging membrane lipids. Detailed analysis indicates a significant sequence similarity between a subset of Bcl-2 family proteins including Bid and Nix and plant lipid transfer proteins. The similar structural signatures could be related to common interactions with membrane lipids. Indeed, isolated Bid shows a lipid transfer activity that is even higher than that of plant lipid transfer proteins. To investigate the possible relevance of these structure-function correlations to the apoptotic action of Bid, cell free assays were established with isolated mitochondria, recombinant Bid and a variety of exogenous lipids. Micromolar concentrations of lysolipids such as lysophosphatidylcholine were found to change the association of Bid with mitochondria and also stimulate the release of cytochrome c promoted by Bid. The changes in mitochondrial association and cytochrome c release were enhanced by the presence of liposomes of lipid composition similar to that of mitochondrial membranes. Thus, a mixture of liposomes, mitochondria and key lysolipids could reproduce the conditions enabling Bid to transfer lipids between donor and acceptor membranes, and also change its reversible association with mitochondria. Bid was also found to enhance the incorporation of a fluorescent lysolipid, but not of a related fatty acid, into mitochondria. On the basis of the results presented here, it is hypothesised that Bid action may depend upon its capacity of exchanging lipids and lysolipids with mitochondrial membranes. The hypothesis is discussed in relation to current models for the integrated action of pro-apoptotic proteins of the Bcl-2 family.     

细胞凋亡机制的研究进展

以线虫和哺乳动物为实验材料,综述近年来对细胞凋亡机制的研究进展。     

吐温80合并温热诱导BGC-823胃癌细胞凋亡及对Hsp70,Bcl-2和Bax表达的影响

目的　观察膜活化剂吐温 80合并温热作用对BGC 82 3人胃癌细胞生长、凋亡及对Hsp70、Bcl 2、Bax表达的影响。方法　应用MTT法、荧光染色及DNA琼脂糖凝胶电泳 ,测定 0 1%吐温 80与 4 2℃ 10 0min合并作用对BGC 82 3细胞的抑制效应和诱导细胞凋亡的影响 ;应用免疫细胞化学染色 ,观察合并作用后不同时间 (0h、 8h、 16h、 2 4h)BGC 82 3细胞Hsp70、Bcl 2、Bax的表达改变。结果　①吐温 80合并 4 2℃温热作用对细胞具有明显的抑制效应 (P <0 0 0 1)。②合并作用后 2 4h ,可见大量肿瘤细胞凋亡。③合并作用可明显抑制BGC 82 3细胞Hsp70的表达 ;Bcl 2、Bax的表达均增加 ,且Bax的表达强于Bcl 2 ,并全部分布在胞浆。结论　吐温 80合并 4 2℃温热可通过诱导细胞凋亡来抑制肿瘤细胞生长 ,其对细胞Hsp70表达的抑制和对Bcl 2、Bax表达及分布的影响可能与凋亡的发生有关     

胡桃楸提取液诱导Hela细胞凋亡的研究

目的：初步探讨胡桃揪提取液对Hela细胞的凋亡诱导作用。方法：通过形态学观察,琼脂糖凝胶电泳及流式细胞术（FCM）检测凋亡细胞。结果：形态学观察发现核固缩、出现凋亡小体。琼脂糖凝胶电泳可见DNA ladder条带。流式细胞仪检测有凋亡峰。结论：胡桃揪提取液可诱导Hela细胞凋亡。