Cherepenko E, Karpenko O
Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kiev.
Biosci Rep. 1999 Feb;19(1):43-9. doi: 10.1023/a:1020198007883.
The uptake of the aminoacid biosynthesis inhibitor, used as the broad-spectrum herbicide ingredient, glyphosate (N-[phosphonomethyl]-glycine) was investigated in E. coli as a model to study mechanisms of cell resistance to antimetabolites as drugs and pesticides. Unlike the glyphosate-degrading Arthrobacter sp. strain for which the first successful measurement of glyphosate uptake and its inhibition by orthophosphate was reported, E. coli K-12 cannot take up this inhibitor either in the presence of orthophosphate, or after a prolonged starvation for it. However, cells made "competent" after an overnight cold CaCl2 exposure followed by dimethyl sulfoxide (DMSO) treatment could take up this compound (Km for glyphosate uptake, 274 microM). Neither amino acids, belonging to a single transport system, nor orthophosphate gave essential inhibition of glyphosate uptake by these cells.
作为广谱除草剂成分的氨基酸生物合成抑制剂草甘膦（N-（膦酰甲基）甘氨酸）的摄取，在大肠杆菌中进行了研究，以此作为研究细胞对抗代谢物（作为药物和农药）抗性机制的模型。与首次成功测量草甘膦摄取及其被正磷酸盐抑制的草甘膦降解节杆菌菌株不同，大肠杆菌K-12无论是在存在正磷酸盐的情况下，还是在长期缺乏正磷酸盐的饥饿状态后，都不能摄取这种抑制剂。然而，经过过夜冷氯化钙暴露随后用二甲基亚砜（DMSO）处理而变得“感受态”的细胞能够摄取这种化合物（草甘膦摄取的Km为274微摩尔）。属于单一转运系统的氨基酸和正磷酸盐都没有对这些细胞摄取草甘膦产生实质性抑制。
