UC San Diego

Bioluminescence, the production and emission of visible light from a chemical reaction in living organisms, is found in almost every major phylum in the marine ecosystem, but only a few bioluminescent mechanisms are well understood today. The luminous brittlestar Ophiopsila californica produces intense green luminescence from its long arms when mechanically stimulated. Distinctively, the light producing cells (photocytes) of O. californica appear to be of neural origin. Understanding the mechanism of light production in this species could identify novel chemistry and cellular biology for biological light production, which could have additional applied uses in a wide range of fields including neuroscience, other biomedical research, and commercial usages. O. californica bioluminescence is produced by a photoprotein that requires calcium ions as a cofactor. However, previous studies in the Deheyn lab showed that bioluminescence can also be triggered in the absence of calcium in the extracellular environment, thus indicating the possibility that intracellular calcium is somehow involved in the light production mechanism. The goal of my thesis was to investigate whether ryanodine receptors (a type of calcium channel) are involved in the bioluminescence mechanism of O. californica photocytes. I applied pharmacological agents known to activate or inhibit ryanodine receptors from other species on isolated cell suspensions enriched in photocytes and assessed their effect on bioluminescence. My results suggested that ryanodine receptors are not involved in the process. Further research is needed to unveil the cellular mechanisms underlying bioluminescence production by O. californica.