Paraquat toxicity is increased in Escherichia coli defective in the synthesis of polyamines.

AUTOR(ES)

Minton, K W

RESUMO

We have shown that toxicity of paraquat for Escherichia coli is increased over 10-fold in strains defective in the biosynthesis of spermidine compared to isogenic strains containing spermidine. The increased sensitivity of these spermidine-deficient mutants to paraquat is eliminated by growth in medium containing spermidine or by endogenous supplementation of spermidine by the use of a speE+D+ plasmid. No paraquat toxicity is seen in the absence of oxygen, even in amine-deficient strains, indicating that superoxide is the agent responsible for the increased toxicity. However, the specific mechanisms responsible for the increased paraquat toxicity in the spermidine-deficient mutants remain to be determined. The marked sensitivity to paraquat of E. coli deficient in spermidine is of particular interest, since such mutants have no other phenotypic properties that can be easily assayed. This increased sensitivity has been used as the basis of a convenient method for scoring for mutants in polyamine biosynthesis and for the detection of plasmids containing the biosynthetic genes.

Documentos Relacionados

• Formation of a compensatory polyamine by Escherichia coli polyamine-requiring mutants during growth in the absence of polyamines.
• Stabilization of erythrocyte membranes by polyamines.
• Endonuclease IV of Escherichia coli is induced by paraquat.
• The non-enzymatic hydrolysis of oligoribonucleotides VI. The role of biogenic polyamines.
• The Toxicity of Paraquat