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Trimethoprim-resistant mutants of E. coli K12: preliminary genetic mapping

Published online by Cambridge University Press:  14 April 2009

A. S. Breeze ,
P. Sims  and
K. A. Stacey

Summary

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Trimethoprim-resistant mutants of E. coli K12 have been isolated by-serial subculture in progressively higher concentrations of trimethoprim. High-level resistance depends on the accumulation of several mutational changes. Transduction with bacteriophage P1 has shown that all the mutations involved in resistance are associated with a locus, to be called tmr, between pyr A and pdxA and closely linked to pdxA. Resistance is accompanied by, and presumably due to, an increased activity of the target enzyme, dihydrofolate reductase. The tmr locus may include the structural gene for dihydrofolate reductase but the only mutations that have so far been observed are concerned with regulation.

Type
Research Article
Information
Genetics Research , Volume 25 , Issue 3 , June 1975 , pp. 207 - 214
Copyright
Copyright © Cambridge University Press 1975

References

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