稀土元素镝对大肠杆菌生长效应研究

Study of rare-earth element Dy on growth of E.coli

采用酶标仪监测大肠杆菌的生长速度,研究培养液中稀土元素Dy^(3+)浓度对大肠杆菌生长的影响。培养液中添加的Dy^(3+)浓度系列为0~12.8mg/L,培养时间为0~9h。实验结果显示:培养时间为2~3h,任何一个Dy^(3+)浓度的培养液均对大肠杆菌呈现生长刺激作用;3h后,Dy^(3+)浓度低于6.4mg/L的培养液继续保持生长刺激作用,而高于9.6mg/L的培养液则对大肠杆菌生长产生抑制作用;随着培养时间的延长,无论是刺激还是抑制作用均呈现逐渐减弱的趋势;在全浓度范围内,大肠杆菌表现出一致性地随Dy^(3+)浓度升高生长对数期内细胞分裂最活跃的时间点逐渐延后的现象。

In order to study the effect of REE（rare-earth element） Dy3＋ in different concentration on the growth of E. coli,the growth rate of E. coli cultured in broths is monitored by a microplate reader. There are a series of broths containing 0-12.8 mg/L Dy3＋ used in the 9-hours cultivation. The result shows that at the first 2- 3 hours, the whole Dy3＋ concentration series can show a growth-stimulating effect on E. coli; with the beginning of the 3rd hour,Dy3＋ stimulates growth with a concentrations not higher than 6.4 mg/L,and inhibits when the concentration raises to 9.6 mg/L or above; both inhibition and stimulation show a gradual weakening trend with time. In addition,in the whole concentration range,the logarithm of the growth of E. coli consistent delaying with Dy3＋ concentration increases.