Presenter: Nicole Mullen – Neuroscience
Faculty Mentor(s): Karen Guillemin, Steph VanBeuge
Session: (Virtual) Poster Presentation
Resident gut bacteria have the capacity to influence aspects of animal metabolism. Previous research in the Guillemin lab showed that in zebrafish, gut bacteria promote the expansion of insulin- producing cells (IPC) in the pancreas through a secreted bacterial protein, Beta-cell expansion factor A (BefA). This research investigates the role of gut bacteria and BefA to promote IPC development in the fruit fly, Drosophila melanogaster. In Drosophila, there are ~7 IPCs located in each lobe of the brain. Our first aim was to test the effect of germ-free (GF) rearing on IPC numbers in Drosophila. Our second aim tested whether feeding flies BefA could restore IPC numbers in GF flies. We compared the number of IPCs present in GF, conventionally-reared (CV), and GF flies fed BefA. Tissue-specific GAL4UAS/GFP in all groups made IPCs visible after dissection. Our results showed that GF flies have fewer IPCs per lobe than CV flies, indicating that microbiota is required for normal IPC numbers. Further, feeding BefA caused a statistically significant increase in IPC numbers in GF larvae compared to CV. However, transgenic expression of BefA, using the UAS/GAL4 system, yielded a trending but not a significant expansion of IPCs in GF flies. This could be due to the low levels of BefA produced through transgenic expression. These results indicate that the microbiota has a powerful effect on metabolic pathways, and cell development, and can influence the normal development of the fly brain.