The Impact of Bacterial Metabolism on the Response to High Glucose Diets in C. elegans

Norton, Connor

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The Impact of Bacterial Metabolism on the Response to High Glucose Diets in C. elegans

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The plasma membrane is an essential structure that protects the cell from the environment, provides structure, regulates the movement of materials, and carries signals and receptors for cellular communication. Previous work has shown changes in the lipid profile of Caenorhabditis elegans under glucose stress. There are increased concentrations of saturated fats and increased turnover of monomethyl branched-chain fatty acids (mmBCFAs) following glucose exposure. In these studies, C. elegans incorporated glucose by consuming OP50 bacteria grown on glucose-enriched culture media. Here, we wanted to investigate if bacteria are essential agents for digesting glucose and generating glucose-related phenotypes. This comparison allowed us to define whether the lipid changes are a result of nematode or bacterial metabolism and would allow for a further understanding of the response to glucose stresses. For these studies, we examined the lipid population by mass spectrometry which revealed that polyunsaturated fatty acids in PE lipids decreased after 12 hours of 100mM glucose exposure, while monounsaturated fatty acids increased. When presented with the same concentration of glucose, C. elegans that were fed heat-killed bacteria did not exhibit the same decreases in polyunsaturated fatty acids. We conclude that most changes in PC and PE species in high glucose environments require a living bacterial diet. We propose that as C. elegans consume the glycosylated products from OP50, reactive oxygen species are generated that attack the double bonds present on PE lipids of the inner plasma membrane. The loss of these double bonds reduces the fluidity of the membrane and hinders the growth and development of the nematode.

This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its website without editorial or peer review.

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