间硝基苯甲酸稀土配合物与大肠杆菌作用的热动力学研究

用TAMair微量热仪测定间硝基苯甲酸钐与邻菲罗啉配合物[Sm(m-NBA)3phen]2·2H2O在37.00℃时与大肠杆菌作用的产热曲线,进而算出在各种浓度配合物的作用下,大肠杆菌生长代谢的最大发热功率Pmax、速率常数κ、传代时间tG、抑制率I和半抑制浓度cI,50等热动力学参数.结果表明:在低浓度下[Sm(m-NBA)3phen]2·2H2O对大肠杆菌有刺激作用,高浓度下为抑制作用,即稀土配合物对微生物的生长具有双向生物效应,也称为Hormesis效应.     

Effect of microcystin-LR on protein phosphatase 2A and its function in human amniotic epithelial cells

Due to their toxicity, the increased distribution of microcystins (MCs) has become an important worldwide problem. MCs have been recognized as inhibitors of protein phosphatase 2A (PP2A) through their binding to the PP2A catalytic subunit. However, the exact mechanism of MC toxicity has not been elucidated, especially concerning the cellular response and its autoregulation. To further dissect the role of PP2A in MC-induced toxicity, the present study was undertaken to determine the response of PP2A in human amniotic epithelial (FL) cells treated with microcystin-LR (MCLR), one of the MC congeners. The results show that a low-dose treatment of MCLR in FL cells for 6 h induced an increase in PP2A activity, and a high-dose treatment of MCLR for 24 h decreased the activity of PP2A, as expected. The increased mRNA and protein levels of the PP2A C subunit may explain the increased activity of PP2A. Furthermore, MCLR altered microtubule post-translational modifications through PP2A. These results further clarify the underlying mechanism how MCLR affects PP2A and may be helpful for elucidating the complex toxicity of MCLR.     

低剂量农药对绿萝生长的Hormesis效应

研究低剂量百菌清、吡蚜酮对绿萝生长的刺激效应。结果表明：0.1mg·kg^-1、0.2mg·kg^-1吡蚜酮处理后35天,能显著促进绿萝株高增长,同对照相比,绿萝株高分别增加51.91%与82.13%;32mg·kg^-1、64mg·kg^-1百菌清处理后35天,对绿萝根长增长有显著促进作用,分别增加72.72%、67.54%;吡蚜酮可诱导绿萝茎叶重量增长的Hormesis效应。