This document summarizes research characterizing prostaglandins in the Pacific oyster Crassostrea gigas and their role in the oyster's immune response. The researcher identified gene fragments involved in prostaglandin biosynthesis, including a prostaglandin E2 receptor gene that is upregulated after exposure to the pathogen Vibrio tubiashii. Experiments exposing oysters and hemocytes to this pathogen found increased prostaglandin levels and receptor expression. This suggests prostaglandins play a role in the oyster's immune response. The researcher proposes further studies on how environmental stressors may affect prostaglandin regulation and physiology.

1. Characterization of prostaglandins in the Pacific oyster Crassostrea gigas : evidence for a role in immune response Mackenzie Gavery, M.S. Student Roberts Lab

2. Molecules with Diverse Functions Vertebrates Mediate swelling and inflammation (COX inhibitors) Inducing fever Maintaining pregnancy/reproductive timing Regulating ion transport

3. Molecules with Diverse Functions Invertebrates Ion transport Reproduction Immune Response recently discovered a gene encoding prostaglandin E 2 receptor in Pacific oysters significantly upregulated after exposure to Vibrio tubiashii Roberts et al

4. What are prostaglandins? Eicosanoids: a family of biologically active metabolites of C20 polyunsaturated fatty acids. Prostaglandins biosynthesis begins with the from arachidonic acid, an omega-6 fatty acid. prostaglandin E2:

5. Arachidonic Acid Cascade PGE receptor

6. Outline Characterize molecules in prostaglandin pathway ID gene fragments using ESTs Tissue distribution of oyster Isolate complete ORF of oyster COX gene Challenge Experiments Applied research

7. Arachidonic Acid Cascade PGE receptor

8. Sequences PGE receptor ESTs: snail, mussel ESTs: oyster!,mussel AM856036 ESTs: ongoing ESTs: EW777722

9. Data PGE receptor

10. Full-length Sequence PGE receptor STATS : Size: 1700 bp pred. # introns: 10 Amino acids: 587

11. COX Gene Similarities

12. Outline Characterize molecules in prostaglandin pathway ID gene fragments from genomics database Tissue distribution of oyster Isolate complete ORF or oyster COX gene Challenge Experiments Applied research

13. Experiments Vibrio tubiashii exposures whole organism plated hemocytes

14. Analytical Results PGE (ELISA) Receptor (PCR) PGE receptor

15. Vibrio exposure-ELISA results PGE conjugate PGE sample 100% 0%

16. Gill Tissue/Vibrio– qPCR PGE receptor

17. Plated hemocytes/Vibrio - qPCR

18. Outline What are prostaglandins? Characterization of genes involved in biosynthesis of prostaglandins Experiments and Results Applied research

19. Applied Research Physiological Processes: Immune Response Ion transport Reproduction Homeostasis temperature pathogen exposure acidification pesticides

20. Applied Research Prostaglandins appear to play a role in the immune response of oysters. In vitro hemocyte cultures may be a good experimental model to study physiological responses to disruptions of this pathway how would changes in environmental conditions (pollutants, temperature, pH) affect the regulation of arachidonic acid metabolism? What physiological effects might this have?

21. Acknowledgements Advisor, Steven Roberts Research scientist, Sam White Friedman and Seeb Lab