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dc.contributor.advisorSaghatelian, Alan
dc.contributor.authorVinayavekhin, Nawaporn
dc.date.accessioned2013-02-08T16:17:49Z
dash.embargo.terms2013-06-21en_US
dc.date.issued2013-02-08
dc.date.submitted2012
dc.identifier.citationVinayavekhin, Nawaporn. 2012. Metabolomics Strategies for Discovery of Biologically Active or Novel Metabolites. Doctoral dissertation, Harvard University.en_US
dc.identifier.otherhttp://dissertations.umi.com/gsas.harvard:10150en
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:10288438
dc.description.abstractAlong with genes and proteins, metabolites play important roles in sustaining life. There remains much to be learned about the in vivo roles of metabolites. Metabolomics is a comparative tool to study global metabolite levels in samples under various conditions. This dissertation describes the development and application of metabolomics strategies for discovery of biologically active or novel metabolites with priori knowledge about genes, proteins, or phenotypes. The power of metabolomics for discovery of novel metabolites from genes is demonstrated through the work with the pyochelin (pch) gene cluster. Comparison of the extracellular metabolomes of pch gene cluster mutants to the wild-type Pseudomonas aeruginosa (strain PA14) identified 198 ions regulated by the pch genes. In addition to known metabolites, a pair of novel metabolites were characterized as 2-alkyl-4,5-dihydrothiazole-4-carboxylates (ATCs). Subsequent assays revealed that ATCs bind iron and that their production is regulated by iron levels and dependent on pchE gene in the pch gene cluster. Metabolomics can also facilitate discovery of active metabolites from proteins, as shown in the work with orphan nuclear receptor Nur77. We applied a metabolomics platform for detected protein-metabolite interactions to identify lipids that bind to Nur77. Using this approach, we discovered that the Nur77 ligand-binding domain (Nur77LBD) enriched unsaturated fatty acids (UFAs) in tissue lipid mixtures. Subsequent biophysical and biochemical assays indicate that UFAs bind to Nur77LBD to cause changes in the conformation and oligomerization of the receptor. Last, analogous to classic fractionation experiments, metabolomics can also be applied to discover active metabolites from phenotypes. Using combination of genetics, biochemistry, and metabolomics, we identified three phenazine compounds produced by Pseudomonas aeruginosa that are toxic to the nematode Caenorhabditis elegans. 1-hydroxyphenazine, phenazine-1-carboxylic acid (PCA), and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of PCA and pyocyanin are strictly pH-dependent at non-overlapping pH ranges. The diversity within a class of metabolites can be used to modulate bacterial toxicity in different environmental niches.en_US
dc.description.sponsorshipChemistry and Chemical Biologyen_US
dc.language.isoen_USen_US
dash.licenseMETA_ONLY
dc.subjectliquid chromatography-mass spectrometryen_US
dc.subjectmetabolitesen_US
dc.subjectmetabolomicsen_US
dc.subjectchemistryen_US
dc.subjectorganic chemistryen_US
dc.subjectbiochemistryen_US
dc.titleMetabolomics Strategies for Discovery of Biologically Active or Novel Metabolitesen_US
dc.typeThesis or Dissertationen_US
dash.embargo.until10000-01-01
thesis.degree.date2012en_US
thesis.degree.disciplineChemistryen_US
thesis.degree.grantorHarvard Universityen_US
thesis.degree.leveldoctoralen_US
thesis.degree.namePh.D.en_US
dc.contributor.committeeMemberLiu, Daviden_US
dc.contributor.committeeMemberKahne, Danielen_US


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