Functional genomics via metabolic footprinting: monitoring metabolite secretion by Escherichia coli tryptophan metabolism mutants using FT–IR and direct injection electrospray mass spectrometry

Authors

  • Naheed N. Kaderbhai,

    1. Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, Wales, UK
    Search for more papers by this author
  • David I. Broadhurst,

    1. Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, Wales, UK
    Search for more papers by this author
  • David I. Ellis,

    1. Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, Wales, UK
    Search for more papers by this author
  • Royston Goodacre,

    1. Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, Wales, UK
    Current affiliation:
    1. Department of Chemistry, UMIST, Faraday Building, Sackville Street, Manchester M60 1QD, UK.
    Search for more papers by this author
  • Douglas B. Kell

    Corresponding author
    1. Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, Wales, UK
    Current affiliation:
    1. Department of Chemistry, UMIST, Faraday Building, Sackville Street, Manchester M60 1QD, UK.
    • Department of Chemistry, UMIST, Faraday Building, Sackville Street, Manchester M60 1QD, UK.
    Search for more papers by this author

Abstract

We sought to test the hypothesis that mutant bacterial strains could be discriminated from each other on the basis of the metabolites they secrete into the medium (their ‘metabolic footprint’), using two methods of ‘global’ metabolite analysis (FT–IR and direct injection electrospray mass spectrometry). The biological system used was based on a published study of Escherichia coli tryptophan mutants that had been analysed and discriminated by Yanofsky and colleagues using transcriptome analysis. Wild-type strains supplemented with tryptophan or analogues could be discriminated from controls using FT–IR of 24 h broths, as could each of the mutant strains in both minimal and supplemented media. Direct injection electrospray mass spectrometry with unit mass resolution could also be used to discriminate the strains from each other, and had the advantage that the discrimination required the use of just two or three masses in each case. These were determined via a genetic algorithm. Both methods are rapid, reagentless, reproducible and cheap, and might beneficially be extended to the analysis of gene knockout libraries. Copyright © 2003 John Wiley & Sons, Ltd.

Ancillary