[Objective] To determine the resistance of urea hydrolytic bacteria to Hg2+ using single injection isothermal titration calorimetry (SIITC).[Methods] The tolerance of urea hydrolytic bacterium Staphylococcus succinus to Hg2+ toxicity was assessed by SIITC in comparison with the traditional cell growth curves and pH change curves.The correlation between SIITC and the traditional methods was examined.[Results] The maximum heat flux rate and the accumulated heat of adsorption and hydrolysis of urea by S.succinus decreased with increasing Hg2+ concentration up to 10 μmol/L.The maximum heat flux rate decreased from-45 μJ/s for the control to-20 μJ/s for 10 μmol/L Hg2+ treated cells and the accumulated heat decreased from-1 291.90 μJ for the control to-535.75 μJ for 10 μmol/L Hg2+ treated cells.The decreases of heat flux rate and accumulated heat well correlated with the change of solution pH (r=0.928) and cell growth rate OD600 (r=0.955).[Conclusion] SIITC is a potential method to detect tolerance of bacteria to Hg2+.%[目的]利用单针注射等温微量量热滴定法(SIITC)检测尿素水解菌对Hg2+的耐受性.[方法]与传统的细胞生长曲线法和基于尿素水解的pH变化曲线相对比,应用SIITC研究耐盐尿素水解菌Staphylococcus succinus对不同浓度Hg2+的耐受性,通过相关性分析验证SIITC检测细菌对重金属胁迫耐受性的可行性.[结果]S.succinus菌吸附水解尿素的最大热量交换速率和累积热量值随Hg2+浓度升高而降低.最大热量交换速率由不含Hg2+的-45 μJ/s降至10 μmol/L Hg2+处理的-20 μJ/s,吸收热量由-1 291.90 μJ下降到-535.75μJ;不同浓度Hg2+胁迫下S.succinus菌吸附水解尿素的反应热量值与溶液pH以及OD600的相关系数r分别达到0.928和0.955.[结论]SIITC可用来检测Hg2+对尿素水解菌S.succinus的毒性.
展开▼
