English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Under anaerobic conditions Escherichia coli is unable to grow in minimal medium with non-fermentable substrates unless an electron acceptor such as nitrate or fumarate is provided. Mutants defective in the nitrate reductase system have been isolated by several methods. Direct selection for chlorate resistance has been used because the anaerobic sensitivity of E. coli to chlorate depends on the presence of a functional nitrate reductase which reduces chlorate to chlorite with lethal consequences (Piechaud et al., 1967). Mutants defective in nitrate respiration have been isolated by an indirect selection based on their failure to grow anaerobically on an amino acid-enriched lactate plus nitrate medium (Venables & Guest, 1968). They have also been isolated by screening colonies directly for their inability to reduce nitrate to nitrite with formate as the electron donor (Ruiz-Herrera, Showe & DeMoss, 1969). Some seven distinct classes of mutants deficient in the reduction of nitrate have been defined. They have all been designated chl mutants (chlA-F) although some are chlorate-sensitive and others show different degrees of resistance. Furthermore, the selections based either on chlorate resistance or on the inability to reduce nitrate yield entirely different distributions of mutant types (Glaser & DeMoss, 1972). Failure to grow anaerobically on a glycerol plus fumarate medium has been used to isolate E. coli mutants ( f rd ) deficient in fumarate reductase (Spencer & Guest, 1973). This communication reports how attempts to use an analogous lactate plus fumarate medium for isolatingfid mutants led to thediscovery that selection for the ability to grow on this medium provides a new method for the direct selection for chlorate-resistant mutants (chl).

A Novel Method for Isolating Chlorate-resistant Mutants of Escherichia coli K12 by Anaerobic Selection on a Lactate plus Fumarate Medium