基于luxAB标记菌株的发光定量分析及其在镉毒性检测方面的应用

Quantitative Analysis of Luminescence Based on LuxAB-Marked Strain and Its Application in Detection of Cadmium Toxicity

以E.coli(pHN102)为研究对象,探讨了luxAB标记菌株的发光定量方法以及影响其发光测定的相关因素.结果表明,该标记菌株在癸醛诱导发光后存在动态变化的发光曲线,发光强度随时间变化先升后降.增大癸醛浓度会提高发光强度,当癸醛浓度达到1%时出现最大发光值;供试菌株在35℃和pH6条件下的发光强度最大,与E.coli的最适生长条件相一致.应用此标记菌株检测镉(Cd)毒性,其相对发光度与Cd浓度存在负相关,线性回归分析可达到1%显著水平.Cd在LB培养基、M9培养基和水中的EC50值分别为4.27mmol/L、34.8mmol/L和62μmol/L,说明Cd在水介质中的毒性远大于在LB、M9培养基中的毒性.

Quantitative analysis of luminescence based on luxAB-marked strain was made using Escherichia coli （pHN102）. The marked strain showed a typical luminescence response profile, which featured a peak decreased rapidly. A maximum light intensity was observed in the presence of ≥1% decanal concentration. The optimal temperature and pH for light intensity were 35℃ and 6, respectively, which was consistent with the optimal growth condition for E. coll. There was a significant linear relationship between relative light intensity and cadmium concentration. EC50 values of cadmium in LB medium, M9 medium and water were 4.27 mmol/L, 34.8 mmol/L and 62 μmol/L, respectively. The results suggested that cadmium in water was much more toxic than that in LB medium and M9 medium. Fig 6, Tab 2, Ref 16.