镧和铈对两种细菌生长的影响及胞内DNA的荧光光谱分析

为了研究镧，铈对细菌生长及核酸的影响，用光电比浊法测定了镧，铈和钙调蛋白抑制剂(氯丙嗪)存在时两种细菌的生长曲线，并用荧光光谱法研究了镧，铈对小牛胸腺DNA和细菌胞内DNA结构的影响。结果显示适当浓度(200 mg·L-1)稀土元素可以促进细菌的生长和繁殖，比对照提前进入对数期，扫描电镜观察也显示镧，铈可以促进枯草芽孢杆菌个体的生长，菌体体积比对照更大，但促进繁殖的作用会被氯丙嗪抑制，表明镧，铈促进细菌生长的机理可能与钙调蛋白的功能有关;荧光光谱分析显示镧，铈会使小牛胸腺DNA荧光增强，镧、铈浓度分别为5和10 mg·L-1时荧光增强作用最大;但镧使细菌胞内DNA荧光猝灭，铈使其荧光增强，结论认为镧，铈对核酸的影响远比想象的要复杂。

Effect of REE on Growth of Bacteria and Fluorescence spectrum of DNA

Growth curve of bacteria treated by the rare earth elements and calmodulin inhibitor (chlorpromazine) was studied, and the effect of REE on calf thymus-DNA and intracellular DNA in bacteria was studied by fluorescence spectrum. The results showed that the logarithmic phase of growth and fission of bacteria can be advanced by REE, so they grew faster than contrast. At the same time, Bacillus subtilis was found bigger by SEM. But growth and fission was inhibited by chlorpromazine, indicating that the mechanism about growth and fission of bacteria by REE was connected with calmodulin inhibitor. Fluorescence of ct-DNA can be enhanced by REE. But intracellular DNA in bacteria was different, it can be enhanced by Ce(NO₃)₃, quenched by La(NO₃)₃. so we think that the function of REE to biological materials was very complicated.