Discovery of Blood Protein Biomarkers of Domoic Acid Toxicosis in California Sea Lions, (Zalophus californianus)

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Ferrante, Jason Allan
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As Pseudo-nitzschia spp. blooms continue to increase in size, range and frequency along the west coast of the United States, increasing occurrences of domoic acid toxicosis (DAT) in California sea lions is expected to co-occur. Current methods to diagnose sea lions that do not display symptoms of DAT at the time of stranding are time consuming and often inconclusive. Domoic acid is estimated to clear the body of a sea lion in 24 hours, making direct detection difficult. This thesis describes the use of proteomic techniques to explore the blood proteome of the California sea lion in order to discover protein biomarkers of DAT. Three aims were addressed. The first was to optimize a methodology for the depletion of high abundance proteins from plasma prior to performing two-dimensional gel electrophoresis (2DGE). The second aim was utilize the methodology from the first aim to compare the plasma proteomes of sea lions with and without DAT. The final aim was to target a smaller segment of the proteome (cytokines) for comparison with a commercially available assay. The ProteoMiner column was used to normalize plasma protein concentration prior to 2DGE. Comparison of the plasma proteomes of the sea lions yielded 25 proteins that were significantly different. Haptoglobin has been identified as one of the 25, and combined with its putative dominant charge forms, shows promise as a candidate biomarker. Serum cytokine concentrations, when assessed as a group using a neural network model, can remove DAT from the differential diagnosis of a sea lion.
California sea lion -- Ecology -- Pacific Coast (U.S.); Domoic acid -- Toxicology; Pseudo-nitzschia.