Ag（Ⅰ）对大肠杆菌抑制作用影响因素的分析

通过测定在各种条件下Ag（Ⅰ）对大肠杆菌Escherichia coli的生长的抑制作用,系统分析了各参数对Ag（Ⅰ）毒性的影响。结果表明：好氧、厌氧状态下,Ag（Ⅰ）对E.coli的抑制能力基本相同;在LB培养基、氨基酸基本培养基和标准基本培养基中Ag（Ⅰ）开始抑制E.coli生长的浓度差异较大,分别为10、0.5、0.1μmol/L;LB组分中的酵母粉的加入完全消除了Ag（I）对E.coli的抑制作用;此外,菌体浓度越高抑制其生长所需的Ag（Ⅰ）浓度也越高。因此Ag（I）对E.coli生长的抑制作用与氧化应激无关,而与培养基种类、培养基组分及菌体浓度高度相关。

Influencing factor analysis of Escherichia coli inhibition by Ag（Ⅰ）

Ag（Ⅰ） inhibition against Escherichia coli（E.coli） was observed under different conditions,based on which the influencing factors of Ag（Ⅰ） toxicity were analyzed systematically.Toxicity of Ag（Ⅰ） against E.coli was investigated in LB,case-amino acid minimum medium（CAA） and standard minimum medium（MM） both aerobically and anaerobically with different Ag（Ⅰ） concentrations.The influence of branched amino acid and cell concentration to the silver inhibition were also discussed.Results indicated that E.coli was similarly inhibited by Ag（Ⅰ） both aerobically and anaerobically.Inhibition showed high medium dependent,10,0.5,0.1 μmol/L Ag（Ⅰ） were required to initiate toxicity in LB,CAA and MM medium respectively.Sensitivity was completely suppressed in LB medium due to yeast chelation of Ag（Ⅰ）.Furthermore,higher cell density required higher Ag（Ⅰ） concentration to be toxic.Hence,toxicity of Ag（Ⅰ） against E.coli didn’t involve reactive oxygen species,but depended on medium,medium components and cell concentration.