Abstract
Summary
The effects of the herbicide paraquat, 1,1′-dimethyl-4,4′-bipyridirium dichloride (Gramoxone W and Weedol), were studied in Escherichia coli B/r and E. coli Bs-1, which are, respectively, radiation-resistant and radiation-sensitive derivatives of E. coli B.
It was found that paraquat is powerfully bacteriostatic against E. coli. In the range of 10-5 to 10-3 M, paraquat showed similar dose-dependent inhibitory effects on growth rate, synthesis of DNA, RNA, messenger RNA, protein, and glucose utilization. At these concentrations, no significant effect on the bacterial membrane was observed as measured by the release of intracellular phosphate pools. However, approximately 90% of the exposed bacteria, both the radiation-resistant and-sensitive strain and T1 bacteriophage were killed at 10-2 M. A limited study on the HeLa cell indicated that these mammalian cells were also more sensitive to this latter concentration.
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