Iron mediates paraquat toxicity in Escherichia coli.
Iron mediates paraquat toxicity in Escherichia coli.
复制标题
铁介导百草枯对大肠杆菌的毒性。
DOI：
10.1016/s0021-9258(18)67111-x
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
M. Chevion
中科院分区：
文献类型：
--
作者：
P. Korbashi;R. Kohen;J. Katzhendler;M. Chevion
在细菌系统中研究了铁离子在百草枯毒性中的作用。结果表明，添加亚铁可增强杀菌作用，而添加螯合剂，如三乙酸氮酯和去铁胺，其毒性作用显著降低，直至完全消除。细菌杀灭率与百草枯和铁的浓度成正比，符合速率方程：dN/dt=-k[百草枯][Fe2+]。铁的杀伤常数k比铜的相应值小24倍。甘露醇，一种OH。清除剂，在1-50 mM的浓度范围内具有部分保护作用：15-35%。另一方面，组氨酸提供了一种更有效的保护，这可能是由于各种影响的组合。内源性超氧化物歧化酶和过氧化氢酶的诱导提供了部分保护(约25%)。这些发现，连同早期关于铜在百草枯毒性中的作用的研究(Kohen，R.和Chevion，M.(1985)Free Rad)。[中英文摘要]Re.Commun.1，79-88)表明过渡金属在百草枯有害作用的产生中起中心催化作用，可能是通过氧化还原循环和产生羟基。通过特定部位的芬顿反应。
The role of iron ions in paraquat toxicity was studied in bacterial system. We show that addition of ferrous iron led to an enhancement of the bacterial killing, whereas addition of chelating agents, such as nitrilotriacetate and desferrioxamine, markedly reduced, up to a total abolishment, the toxic effects. The calculated rates of bacterial killing are proportional to both paraquat and iron concentrations, and conform to the rate equation: dN/dt = -k[paraquat] [Fe2+]. The killing constant for iron, k, is 24-fold smaller than the corresponding value for copper. Mannitol, an OH. scavenger, has a partial protective effect: 15-35% at concentrations range of 1-50 mM, respectively. Histidine, on the other hand, provided a more efficient protection that may be due to a combination of various effects. Induction of endogenous superoxide dismutase and catalase provided partial protection (about 25%). These findings, together with an earlier study on the role of copper in paraquat toxicity (Kohen, R., and Chevion, M. (1985) Free Rad. Res. Commun. 1, 79-88) indicate that transition metals play a central catalytic role in the production of the deleterious effects of paraquat, probably by redox cycling and producing OH. via the site-specific Fenton reaction.