In partial fulfillment of the requirements for the degree of
Master of Science in Biology
in the
School of Biological Sciences
Benton Jaco
Will defend his thesis
METABOLOMIC ANALYSIS OF PREDATOR URINE FOR ENHANCING OYSTER SHELL STRENGTH AND ECOLOGICAL IMPLICATIONS
13, December 2024
2:00 PM
Thesis Advisor:
Dr. Julia Kubanek
School of Biological Sciences
Georgia Institute of Technology
Committee Members:
Dr. Marc Weissburg
School of Biological Sciences
Georgia Institute of Technology
Dr. Facundo Fernandez
School of Chemistry and Biochemistry
Georgia Institute of Technology
Abstract:
This thesis explores the role of metabolites in blue crab urine that enhance oyster shell strength, with downstream opportunity to address the ecological and economic challenges posed by declining oyster (Crassostrea virginica) populations in the Gulf of Mexico gulf oyster. Gulf oysters are essential to Gulf Coast ecosystems, providing water filtration, carbon sequestration, and coastal protection while supporting a significant industry. However, populations have declined by up to 85% due to overfishing, habitat loss, pollution, disease, predation, and climate change.
Using integrated spectroscopic analyses and database matching, along with oyster growth assays, the study identified a metabolite in blue crab urine that promotes oyster shell strengthening. The study focused on the metabolite most important for oyster shell strengthening based on prior partial least squares regression analysis of mass spectrometric metabolomic data. 3-(1-methyl-1H-imidazol-4-yl) propanoic acid was identified as the primary contributor to this effect, with structurally similar molecules, 3-(1-methyl-1H-imidazol-2-yl) propanoic acid and 3-(1-methyl-1H-imidazol-5-yl) propanoic acid observed in aquarium oyster growth assays to induce similar levels of shell strengthening. This generalized strengthening response reflects oysters’ adaptive strategy as r-selected species, which respond broadly to predator-associated cues.
The findings suggest that applying these chemical cues in oyster hatcheries could help produce a robust oyster spat more resistant to predation. Additionally, the study highlights the increasing power of metabolomic techniques to identify natural products in complex biological samples. Future research should employ and enhance these methods to enable the rapid identification of unknown compounds, which could be applied to conservation efforts to assist in the restoration of populations such as gulf oyster populations.
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