大肠杆菌的直流电场刺激过程

Electrolytic Stimulation of Escherichia coli by a Direct Current

摘要:

以钛网电极和铂网电极对培养瓶中大肠杆菌生长过程进行加电刺激, 研究其在直流电场作用下的生长情况, 并结合循环伏安扫描、恒电流、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)及测定菌体ATP酶活力等技术对大肠杆菌的直流电场刺激过程进行研究。结果表明, 在0?0.2275 mA/cm2范围内, 随着电流密度的增加, 直流电场对大肠杆菌生长量的增长促进作用逐渐增加, 而0.0455 mA/cm2的电场则是获得最大活菌量的最适电流密度; 通过对析氢活性不同的铂网电极与钛网电极通加相同电流密度的电场, 发现铂电极培养体系菌体生长优于钛电极培养体系菌体的生长。经验证发现引起这种变化的原因主要是水的阴极电解产物吸附氢和氢气比例的不同引起的; 同时发现在0.091 mA/cm2电流密度下, 直流电场能有效提高ATP酶的活力, 在8 h时通电菌样酶活为不通电菌样酶活的3.2倍; 通过对0.0455 mA/cm2直流电场刺激后的菌体蛋白进行SDS-PAGE分析发现加电菌体在分子量25 kD与35 kD左右多肽表达量明显高于不加电菌体的多肽表达量, 而在分子量为66.2 kD左右时多肽表达量低于不加电菌体多肽表达量。

Abstract:

Growth behavior of Escherichia coli (E. coli) under the exposure to direct current (DC) was studied in this paper, with electrolytic stimulation on the culture flask of E. coli using gauze titanium and platinum electrodes. The electric field-activated mechanism was also investigated by cyclic voltammestry technique, constant direct current technique, SDS-PAGE as well as enzyme activity assay of ATPase. The results show that direct current can promote the growth of E. coli under the current density of 0.2275 mA/cm2, and the growth speed is gradually accelerated with increasing current density, but 0.0455 mA/cm2 is the optimal current density to obtain the maximum viable cells. When the same current density electric field is applied to Pt electrodes and Ti electrodes, the Pt electrode culture system is superior to Ti electrode culture system. The cathode electrolysis products of water are the primary factor for the difference, which include adsorbed hydrogen and H2. It is also found that the 0.091 mA/cm2 direct current can promote ATPase activity effectively, with 3.2 times at most after 8 hours. Bacterial proteins about 25 kD and 35 kD are expressed higher while proteins of 66.2 kD are expressed lower after (under) electrolytic stimulation of 0.0455 mA/cm2 direct current.