Characterization of (68)Zn uptake, translocation, and accumulation into developing grains and young leaves of high Zn-density rice genotype

Zinc (Zn) is an essential micronutrient for humans, but Zn deficiency has become serious as equally as iron (Fe) and vitamin A deficiencies nowadays. Selection and breeding of high Zn-density crops is a suitable, cost-effective, and sustainable way to improve human health. However, the mechanism of high Zn density in rice grain is not fully understood, especially how Zn transports from soil to grains. Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique. At seedling stage, IR68144 showed higher ⁶⁸Zn uptake and transport rate to the shoot for the short-term, but no significant difference was observed in both genotypes for the long-term. Zn in xylem sap of IR68144 was consistently higher, and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient (2.0 μmol/L) or surplus (8.0 μmol/L) Zn supply level. IR64 and IR68144 showed similar patterns of ⁶⁸Zn accumulation in new leaves at seedling stage and in developing grains at ripening stage, whereas ⁶⁸Zn in new leaves and grains of IR68144 was consistently higher. These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains.     

蛋白激酶Cα-EGFP及其突变体真核表达载体的构建和在C2C12细胞中的表达

目的研究PKCα结构与转位的关系.方法用PCR的方法构建了4个PKCα突变体,在DNA连接酶的作用下与pEGFP-N1结合后转移至质粒中,构建PKCα突变体-EGFP真核表达载体.观察它们在C2C12细胞中的表达及转位情况.结果pPKCα-EGFP-N1转染C2C12肌细胞24h后,细胞内表达的PKCα-GFP融合蛋白主要定位于细胞浆,细胞核中未见分布.pPKCα-βI-EGFP-N1、pPKCβI-α-EGFP转染C2C12细胞24h的表达产物集中在胞浆.pPKCα(-)-EGFP-N1、pPKCα(m)-EGFP-N1转染C2C12细胞24h的定位与野生型明显不同.结论PKCα的调节区(C1V1C2)尤其是RACK结合区(C2)、PKCα的催化区(C3V4C4)尤其是ATP结合位点与PKCα的转位密切相关.     

花样滑冰男子自由滑勾手跳跳跃动作的三维运动学分析

使用三台数码摄像机对2003年北京世界花样滑冰大奖赛的11名男子运动员(其中3名为中国运动员)进 行拍摄,本文选取了高松、瑞斯特考特、张民三名运动员的勾手跳跳跃动作的图像,采用美国爱利尔运动解析软件 系统处理得到其运动学参数,最后结合勾手跳跳跃技术动作的原理对数据进行分析得出结论。     

农村剩余劳动力转移:困境与对策

本文从我国的农村潜在的巨大就业压力形成的原因出发,分析了我国农村剩余劳动力转移困境,探讨农村剩余劳动力转移的方法和对策。