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Marine organisms such as Mytilus edulis L (the blue mussel), Crassostrea virginica (the eastern oyster), and Mercenaria mercenaria (the hard shell clam) produce structural proteins and peptides that are critical in adhesive strategies as well as the formation of new shell. The unique properties of these proteins and peptides are induced by their specific amino acid composition. One unique catecholic amino acid is of utmost importance: L 3,4-dihydroxyphenylalanine (L-dopa), which has been implicated in the enzymatically catalyzed sclerotization (or cross-linking) of these proteins that can form moisture-resistant adhesive bonds to a variety of substrates, or the formation of an insoluble organic matrix that plays a vital role in biomineralization and shell formation. The exact origin and role of L-dopa found in these structural proteins is still a source of debate within the biomineralization community. Therefore, the focus of this research was to determine the origin and possible role of L-dopa containing proteins involved in the process of biomineralization and the formation of new shell in the three bivalve mollusks previously mentioned. Studies were performed to determine the origin and relative abundance of L-dopa throughout the process of shell growth and regeneration by inducing a cellular response at the shell growth margin and harvesting serum contained within the adductor muscle. Induction of localized shell growth was achieved by notching the shell; the serum was collected from the adductor muscle closest to the notch at a regular time interval, beginning at time of induction. The serum was centrifuged and hemocytes were harvested and rinsed in filtered sea water; the resulting serum supernatant, hemocytes and rinses were analyzed for amino acid composition. Freshly regenerated shell was also harvested from the shell notch and analyzed. All amino acid analysis has been done using liquid chromatography. Preliminary results indicate that L-dopa is produced within the hemocytes of these three organisms.
Douglas C. Hansen
Primary Advisor's Department
Materials Degradation and Electrochemical Engineering (Research Institute-Materials Engineering)
Stander Symposium poster
Tidball, Wesley D., "The Origin and Possible Role Of L-dopa Containing Proteins in Biomineralization Processes" (2013). Stander Symposium Posters. 361.