M.S. (Master of Science)
Department of Biological Sciences
Bacterial growth; Methionine sulfoxide; Escherichia coli
Escherichia coli grew anaerobically in a complex medium with glycerol as the carbon source and methionine sulfoxide (MetSO) as the terminal electron acceptor. MetSO reductase activity, measured with NADPH as the electron donor, was present only when the particulate and supernatant fractions of extract preparations were present. NADH and sodium dithionite could also serve as electron donors for MetSO reduction. MetSO reductase activity was shown to be constitutive and not repressed by oxygen. Mutants of E^ coli blocked in the biosynthesis of menaquinone (men) were unable to use MetSO as an electron acceptor to glycerol complex media. Growth of men mutants could be restored by the addition of menaquinone intermediates in the medium. MetSO reductase activity in extracts of men mutants was absent unless cells used to prepare extracts were grown in the presence of menaquinone precursors. The requirement of a molybdenum cofactor in MetSO reduction was shown by the inability of chi mutants, known to be defective in molybdenum processing, to grow in glycerol plus MetSO media. It is known that anaerobic growth of chlD mutants with nitrate as the electron acceptor can be restored by high concentrations (10 mM) of molybdate. Growth of the chlD mutant in glycerol MetSO media could be restored by high concentrations of molybdate, reductase activity in extracts of chi mutants was but activity in extracts of the chlD mutant could MetSO absent be restored by growth of the cells in 10 mM molybdate.
Sanchez, Benjamin A., "Methionine sulfoxide as an electron acdeptor [sic] for the anaerobic growth of escherichia coli" (1985). Graduate Research Theses & Dissertations. 3956.
Northern Illinois University
Rights Statement 2
NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.