Isolation, characterization and functional analysis of a cdc48 homologue from tobacco BY-2 cells

The fission yeast Schizosaccharomyces pombe was used to identify genes from tobacco BY-2 cells that may play roles in cell cycle regulation. A cDNA encoding a protein homologous to the yeast CDC48 was isolated and the gene was designated as NtCDC48 . The cDNA contains an open reading frame coding for a predicted protein of 808 amino acids which comprises of two typical ATPase modules (aa 245-374 and aa 518-646) . Overexpression of NtCDC48 in tobacco BY-2 cells led to an increase in the mitotic index as well as to the formation of diffused mitotic spindles. NtCDC48-GFP fusion proteins are distributed ubiquitously through Gl to M phases, yet their subcellular localization varied regularly along with the cell cycle progression. These results indicate that NtCDC48 may play an important role in the regulation of cell cycle in BY-2 cells.     

活体烟草BY-2悬浮细胞微丝骨架的标记

微丝骨架是细胞骨架的重要成员,在细胞的多项生理活动中发挥着重要作用.本论文利用荧光标记鬼笔环肽技术和GFP融合蛋白技术,对活体烟草BY-2悬浮细胞中微丝骨架的标记方法进行了探索,结果表明,10nmol/L的Alexa488-Phalloidin为细胞微丝骨架标记的最佳浓度,利用PCR等技术构建pPZP-NtFABD2-GFP植物表达载体后,转化烟草BY-2悬浮细胞,激光共聚焦扫描显微镜观察发现,NtFABD2-GFP融合蛋白能够清晰地显示活体烟草悬浮细胞内的微丝骨架.这些结果为进一步深入研究微丝骨架在活体植物细胞中的功能奠定了基础.     

烟草悬浮系培养与细胞器的分离

通过诱导BY-2型烟草叶片愈伤组织,进一步建立烟草细胞悬浮系．酶解去壁从细胞悬浮系中获得原生质体,用含有0．5％Triton X-100的CSK缓冲液破裂细胞膜,释放出细胞器,再通过不连续的蔗糖,Percou梯度进行速率区带离心,分离纯化出细胞核和叶绿体,通过分离、纯化细胞核的对照实验证明不同培养条件对烟草细胞悬浮系的生长和周期具有显著影响。     

6-溴异香兰素诱发人宫颈癌上皮细胞纺锤体损伤及有丝分裂灾变死亡

 研究香兰素衍生物中的6-溴异香兰素（6-溴-5-羟基-4-甲氧基苯甲醛,BVAN08）对人宫颈癌上皮（HeLa）细胞纺锤体结构、有丝分裂的影响,及杀死癌细胞的相关机制,为开发新的抗癌药物提供理论依据。研究发现BVAN08对体外培养的人HeLa细胞具有剂量依赖性致死效应。通过抗?琢-微管蛋白抗体和抗?茁-微管蛋白抗体免疫荧光标记和激光共聚焦显微镜观察发现其机制是：BVAN08对细胞纺锤体结构造成破坏,诱发产生大量的多中心体细胞,使细胞阻滞在有丝分裂期。异常多极纺锤体细胞的百分率与BVAN08呈浓度依赖效应关系。荧光染料Hoechst33258染色观察到多微核或细胞核割裂和染色质凝集现象,也证实BVAN08诱发Hela细胞有丝分裂灾变死亡。同时免疫印迹实验还发现,BVAN08可导致细胞周期转录调节因子FoxM1（Forkhead box）及其下游靶分子CyclinB1的降解,参与有丝分裂的FoxM1蛋白失活,这表明BVAN08通过抑制FoxM1蛋白的表达是导致细胞纺锤体装配异常、细胞发生有丝分裂灾变死亡的分子机制之一。研究结果提示BVAN08诱发Hela细胞新的死亡方式,具有被开发为新型抗癌药物的潜力。     

桑叶对乳腺癌肿瘤血管内皮细胞抑制作用的研究

本文通过流式细胞仪(FCM)和酶联免疫吸附法(ELISA)来研究桑叶对乳腺癌肿瘤血管内皮细胞(ECs)细胞凋亡、细胞周期及内皮细胞生长因子受体-2(VEGFR-2)的影响.FCM分析表明,桑叶中有效成分能够诱导异常增殖的内皮细胞凋亡,使细胞周期停滞在DNA合成期,有效阻止内皮细胞的有丝分裂(P0.05);ELISA法结果表明,VEGFR-2的表达受到明显的抑制(P0.05).以上结果证实桑叶能够有效促进乳腺癌肿瘤血管内皮细胞的凋亡、影响其细胞周期的分布、抑制乳腺癌肿瘤血管内皮细胞生长因子受体-2的表达,对其增殖具有抑制作用.     

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.     

拟南芥中一个经典阿拉伯半乳糖蛋白的亚细胞定位

为确定拟南芥中一个经典阿拉伯半乳糖蛋白(arabinogalactan-protein,AGP)的亚细胞定位,克隆了这个基因的编码区,与绿色荧光蛋白(GFP)基因构建融合表达载体,经农杆菌介导转化烟草BY-2悬浮细胞.利用激光扫描共聚焦显微镜,在稳定转化的BY-2细胞表面观察到绿色荧光.研究结果表明,此AGP分布在细胞膜表面.     

烟草悬浮培养细胞的建立及其对机械刺激的敏感性研究

文章以幼嫩烟草茎髓为实验材料进行愈伤组织的诱导,确定了建立烟草悬浮培养细胞初期愈伤组织和液体培养基的最佳配比,以及烟草悬浮培养细胞的最佳继代量和继代时间,并以此为材料研究了烟草悬浮培养细胞对机械刺激的敏感性。     

生物量对黄花蒿悬浮培养细胞生长的影响

黄花蒿细胞悬浮培养过程中，分别以１０、３０、６０、８０ｇ／Ｌ的接种量进行细胞生长的对比实验．在所述培养条件下的最适起始细胞浓度为鲜重６０ｇ／Ｌ培养基．起始培养的细胞浓度直接影响细胞的生长周期增殖倍数．起始浓度越高，细胞生长周期越短，但细胞的增殖倍数越小．起始细胞浓度对黄花蒿悬浮培养细胞对数生长期的比生长速率影响不大．     

机械刺激对烟草悬浮培养细胞耐盐和重金属胁迫的影响

机械刺激(mechanical stimulation,MS)是自然界中普遍存在但又易被忽视的一种非生物胁迫因子.用提高摇床转速的方式对烟草悬浮细胞施加机械刺激,发现机械刺激可提高烟草悬浮培养细胞在盐和重金属胁迫下的存活率和再生能力,缓解盐和重金属胁迫下的细胞活力丧失和丙二醛( malonaldehyde,MDA)含量的积累.这些结果表明机械刺激可诱导烟草悬浮细胞耐盐和重金属胁迫耐性的形成.     

Apoptosis induced by （DIPP-L-Leu）2-L-Lys-OCH3 in K562 cells

Apoptosis as a mechanism of deleting cells from tissues plays an important role in physiological and varieties of pathological situations, especially cancer conditions. In order to search for tumor cells apoptosis inducers, the inhibition effects on K562 cells of N-phosphoryl dipeptide methyl esters were studied by MTT assays, and (DIPP-L-Leu)2-L-Lys-OCH3 was the compound which had the best activity. From the studies of the typical apoptotic morphologic changes, DNA agarose gel electrophoresis, and flow cytometry analysis, it could be concluded that (DIPP-L-Leu)2-L-Lys-OCH3 could induce apoptosis of K562 cells in a dose-dependent manner, and the IC50 was 22.66 μmol/L according to MTT assays.     

埃克替尼对人涎腺腺样囊性癌ACC-M细胞周期的影响

分别应用0、10、20、40μmol/L盐酸埃克替尼(icotinib hydrochloride)处理体外培养的人涎腺腺样囊性癌ACC-M细胞,采用流式细胞仪分析药物作用24、48、72h后ACC-M细胞周期变化;同时应用间接免疫荧光联合流式细胞技术与免疫细胞化学方法,检测其对ACC-M细胞CyclinD1、P21蛋白表达的影响.结果显示,G0/G1期细胞比例随着盐酸埃克替尼浓度与作用时间的增加而增加,经统计学分析,G0/G1期阻滞作用与盐酸埃克替尼浓度、作用时间成正相关;盐酸埃克替尼作用于ACC-M细胞后,CyclinD1蛋白表达降低,P21蛋白表达增加.实验结果表明,盐酸埃克替尼可能通过下调CyclinD1蛋白的表达,上调P21蛋白的表达,改变ACC-M细胞周期分布,诱导ACC-M细胞周期阻滞于G0/G1期.     

东北红豆杉细胞悬浮培养研究

东北红豆杉（Taxus cuspidata sieb et zucc)幼茎诱导的愈伤组织经多次继代培养,选择生长旺盛,紫杉醇含量高的愈伤组织进行细胞悬浮培养,建立了东北红豆杉细胞悬浮系,同时,对影响愈伤组织进行细胞悬浮培养,建立了东北红豆杉细胞悬浮系,同时,对影响愈伤组织继代培养及细胞悬浮培养的条件进行了研究,确定了适合愈伤组织生长的条件以及影响细胞悬浮培养的主要因素。     

百草枯对人肝HepG2细胞生长和周期的影响

为全面理解百草枯(PQ)对人肝的毒性效应,寻找新的方法增强肝对PQ的解毒能力,本文采用显微观察和流式细胞术分析了PQ处理24h对人肝HepG2细胞生长和周期的影响.结果显示,7.21mg/L的PQ处理即可抑制部分HepG2细胞的生长,23.36mg/L的PQ可导致HepG2细胞周期停滞,S期细胞明显减少、G1和G2期细胞明显增多,且细胞生长抑制和周期受阻程度与PQ处理浓度呈正相关.该结果表明,PQ对HepG2细胞的生长和周期具有明显阻滞作用,生长因子类或促增殖类药物可能有助于增强人肝对PQ的解毒能力.