Studying mutualism and pathogenesis using UPLC-HRMS based metabolomics

In this thesis, mutualistic and pathogenic relationships between Galleria mellonella, Steinernema carpocapsae, and Xenorhabdus nematophila were studied. Using Ultra Performance Liquid Chromatography in tandem with High Resolution Mass Spectrometry (UPLC-HRMS), metabolite intensities were measured. In the first experiment, Galleria mellonella was infected with entomopathogenic Steinernema carpocapsae nematodes and the progress of infection was analyzed using metabolomics. In a mutualistic relationship, Steinernema carpocapsae nematodes transport Xenorhabdus nematophila bacteria into the host and kill the insect for nematode development. Metabolomics analysis of Galleria mellonella showed statistical significant differences in metabolite intensities as infection progressed in both known and unknown spectral features.In the second experiment, the metabolic profile of two strains of Xenorhabdus nematophila were studied for differences in colonization abilities induced by the nematode intestinal location (nil) locus. The nil locus was deleted in both strains, but the control strain was complemented for the deletion. Metabolomics analysis using UPLC-HRMS was performed on both whole cell samples and supernatant samples with an interest in known and unknown spectral features. Of metabolites detected, 18 more were detected in the whole cell samples verses the supernatant samples. Unknown spectral features were analyzed with 1301 more spectral features being detected in the whole cell samples. After reduction by statistical significance, unknown spectral features were analyzed for database matches by exact mass.