Contrasting fates of the paraquat monocation radical in Escherichia coli B and in Dunaliella salina

Haim D. Rabinowitch, Gerald M. Rosen, Irwin Fridovich*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Anaerobic cultures of Escherichia coli exposed to paraquat (PQ2+) accumulated the corresponding monocation radical PQ{plus sign, dot below} both within the cells and in the suspending medium. The green alga, Dunaliella salina, which is susceptible to a light- and O2-dependent toxicity of PQ2+, was nevertheless unable to cause accumulation of PQ{plus sign, dot below}when illuminated anaerobically and could, moreover, discharge the ESR signal and the blue color of PQ{plus sign, dot below} accumulated by E. coli. Spin trapping allowed demonstration of the photoproduction of O-2 within D. salina and of the augmentation of that O-2 production by PQ2+. D. salina appears to contain an electron sink and a heat-labile mechanism for transferring electrons from PQ{plus sign, dot below} to that sink. This mechanism was demonstrable anaerobically but did not prevent PQ{plus sign, dot below}-mediated O-2 production under aerobic conditions.

Original languageEnglish
Pages (from-to)352-356
Number of pages5
JournalArchives of Biochemistry and Biophysics
Volume257
Issue number2
DOIs
StatePublished - Sep 1987
Externally publishedYes

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