Publication Date

1992

Document Type

Dissertation/Thesis

First Advisor

Meganathan, Rangaswamy

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

LCSH

Bacteria--Cytochemistry; Escherichia coli

Abstract

Escherichia coli K-12, when grown anaerobically on glycerol, can utilize dimethyl sulfoxide (DMSO) and trimethylamine N-oxide (TMAO) as terminal electron acceptors. TMAO reductase and DMSO reductase are the two enzymes involved in the reduction of these compounds. The overlapping substrate specificities of these enzymes have led to confusion as to their in vivo role. We have isolated transposon TnlO insertion and deletion mutants in the dins operon. These mutants failed to grow on glycerol/DMSO but their growth on glycerol/TMAO was unaffected. These mutants also retained the ability to utilize other N-oxides such as nicotinamide N-oxide (NAMO), nicotinic acid N-oxide (NAO)and adenine N-oxide (ANO) as terminal electron acceptors. To further clarify these results, we heated cell-free extracts from wild type cells of E. coli at 70°C for 15 min resulting in selective inactivation of DMSO reductase activity with TMAO reductase activity unaffected. These results indicate that TMAO reductase, and not DMSO reductase, is the major enzyme involved in TMAO reduction.

Comments

Includes bibliographical references (pages 20-23)

Extent

vi, 23 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

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.

Media Type

Text

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