Induction of Apoptosis in Protoplasts and Suspension Cultures of Plant Cells

IntroductionApoptosisisacellularautodestructionprocessfortheactiveeliminationofunwantedcells[1].Apoptosishasbeenobservedinmanyanimaltissuesandwasfoundtoplayavitalroleinnormaldevelopment,maintenanceofhomeostasisandpathologicalprocessesassociatedwithvariousdiseases[2,3].Thereismoreandmoreevidenceshowingthatapoptosisalsooccursinhigherplants[4].However,comparedwiththeresearchinanimals,thestudyofapoptosisinplantsisstillinitsinitialstage.Ourstudyinvestigatestheapoptosis-inducingeffectsofsomeabiotic…     

端粒酶高表达对Bcl-2的负调节使用

端粒酶和Bcl-2均对调控细胞凋亡有重要作用，端粒酶的活化及Bcl-2的表达失调还与肿瘤的形成密切相关。端粒酶与Bcl-2之间的确切联系目前仍不清楚。研究活化的端粒酶对Bcl-2表达的影响，首先发现在端粒酶阳性的肿瘤细胞或转化细胞中，Bcl-2的表达明显低于端粒酶阴性或活性低的细胞。进而，在外源性端粒酶催化亚基基因转化的成纤维细胞中，重新表达端粒酶的同时，Bcl-2的表达受到明显的抑制。进一步提示，端粒酶表达与Bcl-2的表达存在某种内在联系，前者的高表达可能对Bcl-2的表达起负调节作用。     

小鼠胸腺退化过程中多胺含量的变化动态

近年来,越来越多的研究表明,衰老与有机体的免疫系统,特别是细胞免疫系统活性的下降有密切关系。由于胸腺作为中央淋巴器官在免疫系统中的特殊地位,关于胸腺退化与衰老关系的研究自然会受到特别的重视。     

p-氟代苯丙氨酸对日本牵牛开花的光周期诱导的抑制作用

诱导暗期中施用0.04mol/1 p-氟代苯丙氨酸(FPA)于日本牵牛子叶,可抑制其开花诱导。在诱导暗期的第8h施用,开花反应(包括每株花芽数和开花植株百分数)的抑制     

Apoptosis Induced by High Concentrations of Nicotinamide in Tobacco Suspension Cells

As an inhibitor of poly(ADP-ribose) polymerase (PARP), nicotinamide has a restraining effect on apoptosis at certain low concentrations. In our present study, apoptosis induced by high concentrations of nicotinamide was observed in tobacco suspension cells. When cells were preincubated with 250 mmol/L nicotinamide for 24 h, the hallmarks of apoptosis were detected, including DNA fragments increasing in size by multiples of 180-200 bp，the condensation and peripheral distribution of nuclear chromatin, and a positive reaction to the TUNEL assay. At the same time, the degradation of PARP and the reduction in the potential of the inner membrane of mitochondria appeared in apoptotic cells induced by high concentrations of nicotinamide. This result indicates that apoptosis induced by high concentrations of nicotinamide is associated with caspase-3-1ike activity and with the opening of mitochondrial permeability pores. These results partially support the hypothesis that high concentrations of PARP inhibitor could force cells to enter an apoptotic pathway by delay of DNA repair in replicating cells.     

极谱法测定植物中聚(ADP-核糖基)聚合酶活性

建立了一种简便,灵敏,可信的ＰＡＲＰ活性测定的非同位素方法,即用线性扫描极谱法测出植物中ＰＡＲＰ酶促反应产物烟酰胺的含量,从而测定了ＰＡＲＰ的活性。ＮＩＣ的检测限达０．０３μｍｏｌ／Ｌ,线性关系为０．０６－５μｍｏｌ／Ｌ,相关系数ｒ＝０．９９９,ＮＩＣ的回收率约达９２％－９８％,相对标准偏差小于６．６％《     

植物非细胞凋亡体系的构建

为了研究植物细胞的的凋亡机制,利用热激诱导凋亡的烟草细胞中的胞质溶胶,构建了植物非细胞凋亡体系,温育在此体系中的正常烟草细胞核,出现染色持固缩,形成凋亡小体等典型的细胞凋亡的形态学特征,ＤＮＡ电泳分析观察到核小体间ＤＮＡ断裂所形成的梯状条带,将细胞核进行了彗星电泳观测到彗星状的核ＤＮＡ片段的迁移,抑制剂研究发现ｐｅｐｓｔａｔｉｎＡ,ｌｅｕｐｅｐｔｉｎ及ＥＤＴＡ均不能抑制上述形态学变化及生化变化,而     

丁酸钠诱导HeLa细胞凋亡过程中端粒酶活性及端粒长度的变化

研究了丁酸钠诱导的ＨｅＬａ细胞凋亡过程中端粒酶活性和端粒长度的变化。丁酸钠处理４８ｈ后,ＨｅＬａ细胞表现出明显的凋亡特征：染色质凝集,形成凋亡小体,ＤＮＡ在核小体间断裂并降解产生梯状电泳图谱。凋亡细胞中端粒酶活性无显著改变,端粒长度却急剧缩短;抑制端粒酶活性后,细胞对凋亡刺激的易感性增强,端粒的降解加快。以上结果表明,丁酸钠诱导的细胞凋亡与端粒长度密切相关,但不影响端粒酶的活性。端粒酶则可以通过保     

热激诱导烟草悬浮细胞的凋亡

烟草细胞经４８℃处理４ｈ再正常培养可出现典型的细胞凋亡的变化。ＤＮＡ梯状条带检测结果显示,４８℃处理４ｈ的样品,其基因组ＤＮＡ被降解形成明显的ＤＮＡ梯状条带,表明热激诱发了ＤＮＡ的核小体间的断裂,从而表现出典型的凋亡细胞的生化特征,而同样温度处理２和９ｈ的样品虽然仍可观察到ＤＮＡ梯状条带,但远不如处理４ｈ的清晰。对处理４ｈ的样品进行核ＤＮＡ断裂的原位检测,多数细胞显示极强的ＴＵＮＥＬ阳性,表明其细