Metabolomics aims to answer biological questions using analytical chemistry tools by measuring alterations in intracellular metabolite levels. In conjunction with their rates of change, a temporal snapshot of how these small molecules fluctuate in major cellular pathways can also be assembled. Using these metabolomic approaches, it is possible to elucidate how genetic mutations cause a global metabolomic shift in the model organism, Escherichia coli. E.coli MG1655 was modified by removing a key enzyme in the tricarboxylic acid cycle (TCA), making a total of eight strains, each with a unique TCA gene deleted. High resolution mass spectrometry was utilized to gather information on hundreds of metabolites in a single untargeted analysis. Specifically, the metabolomic and lipidomic profiles were collected as well as a metabolite flux analysis via 13C-labeled glucose incorporation rates into metabolites over time. Data analysis tools such as heat maps and partial least squares discriminant analysis plots were used to determine how specific gene mutations affected the entire metabolome and associated pathways. The analysis revealed drastic changes in the mutant strains versus the wild type within the pyrimidine synthesis pathway, energy production, and amino acid metabolism. Additionally, specific mutations impacted the composition of lipid species present, showing the acnB mutants had decreased levels of phosphatidylethanolamines. Despite each strain having a mutation in the same pathway, they adjusted their metabolic profiles uniquely in order to continue to survive.

Analyzing global metabolite variation based on mutations in the tricarboxylic acid cycle of Escherichia Coli using high resolution mass spectrometry

253rd National Meeting (2017)

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