Meeting Abstract
The Portuguese Man of War (Physalia physalis) is a cnidarian that lives at the surface of the ocean and travels by catching wind in a sail filled with carbon monoxide. A number of aspects of its physiology remain enigmatic, including how it is able to tolerate high levels of UV-radiation (UVR) to minimize cellular and genomic damage. To better understand the mechanism by which Physalia survives under regimes of high UVR, we used UV photography to determine the differential UV-absorbing capabilities of Physalia tissue types. We extracted and characterized Physalia’s UV-absorbing molecules using HPLC-tandem mass spectrometry. One class of UV-absorbing molecules are the mycosporine amino acids. Mycosporine amino acids are derived from the same biochemical pathway used to synthesize aromatic amino acids. Enzymes necessary for the synthesis of both aromatic and mycosporine amino acids are thought to be absent in metazoans. Therefore, metazoans must obtain these amino acids from their diet or symbionts. By sequencing Physalia’s genome, we provide evidence that some of the enzymes for mycosporine amino acid synthesis are present and expressed across most tissues. Additionally, analysis of new cnidarian genome sequence data provides evidence that several other cnidarians endogenously possess enzymes employed in mycosporine amino acid synthesis. Endogenous production of mycosporine amino acids may be one way that Physalia manages to thrive under high UVR conditions.
