M.S. (Master of Science)
Department of Biological Sciences
Escherichia coli--Genetics; Mutagenesis; Operons; Gene fusion
In Gram negative bacteria a number of iron-responsive gene products are regulated by the Fur protein. Mutations in the fu r gene are reported to be pleiotropic. In this study, fu r mutants were isolated by mini-transposon mutagenesis of an entC-lacZ operon fusion strain followed by direct selection on MacConkey agar. The majority of the mutants were not pleiotropic. However, two of the mutants showed slow growth on succinate, fumarate and acetate, and a third on acetate alone as carbon sources. Revertants that regained the ability to use these carbon sources were obtained with ease; these revertants retained th e-fur phenotype. The fu r mutants produced from 1.5 to 3-fold higher levels of enterobactin when grown in iron sufficiency compared to iron deficiency. The pleiotropy attributed to fu r is probably due to secondary mutations induced by the selection procedure combined with the high rate of appearance of spontaneous mutations.
Park, Sungkyung, "Direct selection of non-pleiotropic fur mutants by mini-transposon mutagenesis of Escherichia coli with an entC-lacZ operon fusion" (1998). Graduate Research Theses & Dissertations. 2247.
Northern Illinois University
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