Ligularia intermedia growing at different altitudes were used to investigate the mechanism of ultraviolet (UV) resistance on physiological aspects in the field. The tests compared the absorbance of the UV absorbin...Ligularia intermedia growing at different altitudes were used to investigate the mechanism of ultraviolet (UV) resistance on physiological aspects in the field. The tests compared the absorbance of the UV absorbing compound, the content of chlorophyll a, chlorophyll b, and carotenoids, and the activities of peroxidase (POX) and superoxide dismutase (SOD) in Ligularia intermedia growing at three different altitudes on Dongling Mountain in northern China. There were no significant differences between the plants growing at 1160 m and 1820 m. However, all of these factors increased dramatically at 2190 m. The results indicate that the UV resistance of the plants mainly depends on the mechanism of filtering the radiation and preventing the reactive oxygen species (ROS) damage produced by UV B展开更多
文摘TGF-β/Nodal信号通路在斑马鱼胚胎背腹分化过程中发挥重要作用。为了进一步探究该信号通路的功能及作用机制,文章采用酵母双杂交的方法,以斑马鱼Smad2/3a为诱饵蛋白筛选得到一系列Smad2/3a的互作蛋白,其中之一为Rbb4l(Retinoblastoma binding protein 4,like)。已有的报道表明,Rbb4l的人类同源蛋白RBBP4(Retino blastoma binding protein 4)是染色质修饰相关的复合体的组成成分,但它在脊椎动物胚胎发育过程中的作用还知之甚少。文章通过体外及体内的一系列实验表明,Rbb4l能直接与Smad3a互作,增强TGF-β/Nodal信号。在斑马鱼胚胎中过表达rbb4l导致胚胎的背部化,伴随着背部标记基因表达区域的扩大和腹部标记基因表达区域的缩小。相反,在胚胎中下调rbb4l的表达,可以导致胚胎在24 hpf(hours post-fertilization)左右出现腹部化的表型。文章进一步通过一系列的挽救实验,证明在缺少Nodal信号的情况下,rbb4l的过表达不能引起胚胎的背部化。综上所述,Rbb4l可以增强Nodal/Smad2/3信号,并且这种正向调节的功能依赖于Nodal信号本身。
基金Supported by the Students Research Training(SRT) (No. 2 S0 0 5 ) and the Modern L ife Science Experimental Education Center of Tsinghua U niversit
文摘Ligularia intermedia growing at different altitudes were used to investigate the mechanism of ultraviolet (UV) resistance on physiological aspects in the field. The tests compared the absorbance of the UV absorbing compound, the content of chlorophyll a, chlorophyll b, and carotenoids, and the activities of peroxidase (POX) and superoxide dismutase (SOD) in Ligularia intermedia growing at three different altitudes on Dongling Mountain in northern China. There were no significant differences between the plants growing at 1160 m and 1820 m. However, all of these factors increased dramatically at 2190 m. The results indicate that the UV resistance of the plants mainly depends on the mechanism of filtering the radiation and preventing the reactive oxygen species (ROS) damage produced by UV B
