Minakami H, Kitzler J W, Fridovich I
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710.
J Bacteriol. 1990 Feb;172(2):691-5. doi: 10.1128/jb.172.2.691-695.1990.
Retention of paraquat by Escherichia coli B was greatest after exposure at pH 9.0 and was progressively less after exposure at pH 7.0 and 5.0, respectively. This retained paraquat was capable of persistent growth inhibition. Uptake and retention of paraquat by E. coli B was dependent upon a carbon source, such as glucose. Under comparable conditions E. coli K-12 did not retain paraquat. The lethality of paraquat was seen in TSY medium but not in VB medium. The addition of Soytone, tryptone, or yeast extract, to the VB medium allowed the lethality of paraquat to be seen. A variety of chelating agents, including EDTA, 8-hydroxyquinoline, and o-phenanthroline, prevented the lethal effect of paraquat in TSY medium. Although EDTA protected against the lethality of paraquat, it did not protect against its bacteriostatic effect.
在pH 9.0条件下暴露后，大肠杆菌B对百草枯的保留量最大，而在pH 7.0和5.0条件下暴露后，保留量逐渐减少。这种保留的百草枯能够持续抑制生长。大肠杆菌B对百草枯的摄取和保留取决于碳源，如葡萄糖。在可比条件下，大肠杆菌K-12不保留百草枯。百草枯在TSY培养基中具有致死性，但在VB培养基中则不然。向VB培养基中添加大豆蛋白胨、胰蛋白胨或酵母提取物后，百草枯的致死性就会显现出来。包括乙二胺四乙酸（EDTA）、8-羟基喹啉和邻菲罗啉在内的多种螯合剂可防止百草枯在TSY培养基中的致死作用。虽然EDTA可防止百草枯的致死作用，但它并不能防止其抑菌作用。
