Cu(Ⅱ)、Fe(Ⅲ)和Cr(Ⅲ)在弱酸性条件下对大肠杆菌的毒性和致毒机制  

Toxicity and mechanism of Cu(Ⅱ),Fe(Ⅲ) and Cr(Ⅲ) against Escherichia coli under weak acidic conditions

作　　者：徐芳芳[1,2] 黄满红[1] 陈亮[1] 柿井一男 

机构地区：[1]东华大学环境科学与工程学院,上海201620 [2]日本宇都宫大学材料与环境化学系

出　　处：《环境化学》2012年第12期1840-1848,共9页Environmental Chemistry

基　　金：国家自然科学基金(21007010);教育部博士点基金项目(20090075120007);上海科委项目(09230500200);交通运输部科技项目(2010353343290);湖南省交通厅科研项目(200908)资助

摘　　要：比较了弱酸性条件下Cu(Ⅱ)、Fe(Ⅲ)和Cr(Ⅲ)单独或加入抗坏血酸(L-AscA)对大肠杆菌(E.coli)的毒性,深入分析了Cu(Ⅱ)/L-AscA体系的特性;通过电子自旋共振(ESR)定量分析羟基自由基(.OH)浓度以分析其毒性机理.结果表明,pH 4.0下L-AscA促进了Cu(Ⅱ)、Fe(Ⅲ)而非Cr(Ⅲ)的毒性,三者毒性Cu(Ⅱ)>Cr(Ⅲ)>Fe(Ⅲ).通常被认为无毒的Cr(Ⅲ)却在0.2 mmol.L-1,pH 4.0时表现出了很高的杀菌率.与0.01%L-AscA共存时,Cu(Ⅱ)为200、20μmol.L-1和2、0.2μmol.L-1下,E.coli的存活率分别在30 min和2 h内迅速降至零,且该体系对自然水体中分离所得的其它7种菌株同样具有明显的制御作用.ESR结果表明L-AscA的加入使200μmol.L-1Cu(Ⅱ)反应体系的.OH浓度约提高两倍,.OH浓度呈Cu(Ⅱ)浓度依赖.但在Fe(Ⅲ)、Cr(Ⅲ)/L-AscA体系中未检测到.OH,表明三者对细胞的致毒机制存在明显差异.Toxicity of three transition metal ions investigated under weakly acidic conditions, Furthermore, their cell killing mechanisms resonance （ESR）. L-AscA enhanced Cu（ Ⅱ）, Fe （ Ⅲ ） and Cr（ Ⅲ ） against Escherichia coli was both in the presence and absence of ascorbic acid （L-AscA）. which showed great difference, were studied by electron spin ） and Fe（ Ⅲ ） but not Cr（ Ⅲ） bactericidal efficiency at pH 4.0, under which all cell death was shown in 30 minutes after full contact with 200 μmol · L-1, 20 μmol · L-1 Cu（I1） based on viable cell counting, and 2 hours with 2 μmol · L-1, 0.2 μmol · L-1 Cu（ Ⅱ ）. Cr（Ⅲ） alone, which is widely recognized as innocuous and stable, at 0.2 mmol · L-1, pH 4. 0, also showed surprisingly high disinfection capability. Toxicity in the presence of L-AscA was as follows ： Cu（Ⅱ） 〉Or（Ⅲ） 〉 Fe （ Ⅲ ）. Furthermore, their cell killing mechanisms turned out to be different. Hydroxyl radical produced by Fenton-like reaction was involved in Cupric toxicity, which has been proved by ESR using the spin trapping 3,3,5,5-tetramethyl-l-pyrroline-N-oxide （M4PO）. L-AscA almost doubled .OH concentration produced by 200 μmol· L- 1 Cu （ Ⅱ ）, and OH concentration was positively related to Cu （ Ⅱ ）. In the case of Fe （ Ⅲ） and Cr（ Ⅲ ）, no ·OH was detected by ESR. Their toxic mechanism is complicated and remains to be elucidated.

关 键 词：过渡金属 抗坏血酸 毒性 ESR 

分 类 号：X172[环境科学与工程—环境科学]