Calcium-Mediated Mitochondrial Permeability Transition Involved in Hydrogen Peroxide-Induced Apoptosis in Tobacco Protoplasts

In the present study, we focused on whether Intracellular free Ca^2＋ （[Ca^2＋],） regulates the formation of mltochondrlal permeability transition pore （MPTP） In H2O2-induced apoptosis In tobacco protoplasts. It was shown that the decrease In mltochondrlal membrane potential （△ψm） preceded the appearance of H2O2-Induced apoptosls; pretreatment with the specific MPTP Inhibitor cyclosporine A, which also Inhibits Ca^2＋ cycling by the mitochondria, effectively retarded apoptosls and the decrease In △ψm. Apoptosls and decreased △ψm were exacerbated by CaCl2, whereas the plasma membrane voltage-dependent Ca^2＋ channel blocker lanthanum chloride （LaCl3） attentuated these responses. Chelation of extracellular Ca^2＋ with EGTA almost totally Inhibited apoptosls and the decrease In △ψmInduced by H2O2. The time-course of changes In [Ca^2＋]l In apoptosls was detected using the Ca^2＋ probe Fiuo-3 AM. These studies showed that [Ca^2＋]1 was Increased at the very early stage of H2O2-Induced apoptosls. The EGTA evidently Inhibited the Increase In [Ca^2＋]1 Induced by H=O=, whereas It was only partially Inhibited by LaCl3. The results suggest that H2O2 may elevate cytoplasmic free Ca^2＋ concentrations In tobacco protoplasts, which mainly results from the entry of extracellular Ca^2＋, to regulate mltochondrlal permeability transition. The signaling pathway of [Ca^2＋]1-medlated mltochondrlal permeability transition was associated with H2O2-Induced apoptosis In tobacco protoplaete.     

蛋白质结构信息内蕴含商机

武田制药公司投入大约21亿人民币收购美国Syrrx公司。日本最大的制药公司出资收购这家解析蛋白质立体结构的风险企业，表明了武田公司为推进新药研究而重视对立体结构信息利用的姿态。其他制药企业也开始积极将结构信息应用到新药开发中去。另一方面，一些风险企业也以自主研发的技术为王牌进军蛋白质结构解析的商业领域，新药研制的事业基础得到不断巩固，已有不少成功的例子。蛋白质立体结构信息这个技术瓶颈的解决，终于使停滞不前的基因组新药开发动起来。[编者按]     

西部建成最大放射治疗中心

第四军医大学唐都医院继医用直线加速器和头部、体部X刀之后,新引进的世界最先进的头部伽玛刀和体部伽玛刀,最近通过了国家卫生部和解放军总后卫生部组织的验收。专家们认为,唐都医院如此集中具有世界先进水平的大型放射治疗设备,可以满足各种脑部、体部肿瘤及其他病变患者的不同需要,已成为西部最大的放射治疗研究中心。     

新信号通路可控制神经定向生长

中国科学院遗传与发育生物学研究所黄勋实验室和丁梅实验室以线虫头部的RME神经为模型,通过遗传筛选的方法,找到了一条保守的Wnt信号通路控制RME神经轴突前后轴的生长。     

碳离子辐射诱导的远隔效应

放射治疗诱导的远隔效应能够抑制非辐射区域内肿瘤的生长，目前已有临床和临床前研究表明，常规放疗射线（X射线、γ射线）能够诱导远隔效应的发生，但是对于其发生的机理以及碳离子诱导的远隔效应研究较少。与常规放疗射线相比，碳离子束具有高传能线密度、高相对生物效应、低氧增强比以及复杂DNA损伤等优势，并且具有激活肿瘤细胞更强免疫原性的潜力。本文综述了常规放疗以及碳离子放射治疗诱导的远隔效应及其机理，为寻找更有效的癌症放疗方法提供参考。