铀和铅对枯草杆菌毒性的研究

Toxic effects of uranium and lead to B. subtilis

采用3种方法研究了铀和铅对枯草杆菌的毒性：（1）试纸法测抑菌圈的直径；（2）血球计数板测细菌菌数；（3）高倍显微镜下观察细菌形态和密度的变化。实验考察铀和铅的质量浓度为1～2000mg／L。结果表明：铀和铅对枯草杆菌的生长繁殖有显著影响；铀和铅对枯草杆菌的最大无作用剂量均小于1mg／L；铀对枯草杆菌的致死质量浓度为500mg／L，铅对枯草杆菌的致死质量浓度为1000mg／L。同时，对以上3种方法进行了比较，确定了其各自的应用范围，为重金属对微生物毒性研究方法的选择提供了参考。

The toxic effects of uranium and lead to B. subtilis were evaluated based on three quantitative parameters- diameter of the circle of bacteriostasis, bacterial population measured by Heamacytometer, and changes in shape and density of the bacteria. Both uranium and lead were found to inhibit the growth of B. subtilis at 1 mg/L or lower;the lethal concentration of U and Pb to B. subtilis was 500 mg/L and 1 000 mg/L,respectively. The change in bacterial population was the most sensitive of the three parameters as a simple indicator of the metals＇ toxic effects.