Red Sea Moses Sole

The finless sole secretes a milky ichthyotoxin from the base of its dorsal and cloacal fins. This secretion contains pardaxin, a lipophillic peptide that causes severe plasma membrane disruption resulting in cell leakage. The pardaxin-containing secretion is used as a defensive mechanism against predators including sharks. Pardaxin is irritating to predator fish, particularly affecting the sensitive gills. Eugenie Clark conducted much of the early work on the species. There is much biotechnological interest in pardaxin: early interest focused on potential shark repellent applications while newer research focuses on antimicrobial and neurotoxic potential of pardaxin and its analogues. One toxin produced, pardaxin-1, does have unusual shark repellent and surfactant properties. It created voltage-dependent, ion-permeable channels in membranes and at high concentration it causes lysis in cell membranes. This toxin has been demonstrated to be 5–10 times more toxic, cytolytic and active in the formation of pores in cell membranes than the other toxin exuded, pardaxin-2. Mimic octopuses have been known to mimic the finless sole by adapting its shape, colour and texture; these octopuses can also mimic venomous sea snakes and fish.