Pardachirus marmoratus

Pardaxin, a marine neurotoxic polypeptide isolated from the secretion of the flatfish Pardachirus marmoratus or synthesized by the solid phase method, is a single chain, acidic, amphipathic polypeptide with... 

Figure 1. Pardachirus marmoratus fish and the morphology of the toxin secretory glands.

Obviously not all marine toxins arise from adventitious contamination. Marine species also utilise endogenously synthesized toxins for both defensive and offensive strategies. The Red Sea flatfish, Pardachirus marmoratus, secretes a slime which contains the toxin pardaxin. This is a linear 33-residue polypeptide which, upon binding to cells, spontaneously forms pores in the plasma membrane leading to cytolysis and cell death. Interestingly, it has been foimd that pardaxin is an effective shark repellent. 

Lazarovici, P., Primor, N., and Moew, L.M. (1986) Purification and pore-forming activity of two hydrophobic polypeptides from the secretion of the Red Sea Moses sole Pardachirus marmoratus).]. Biol. Chem., 261, 16704-16713. 

OREN z, SHAi Y. A class of highly potent antibacterial peptides derived from pardaxin, a pore-forming peptide isolated from Moses sole fish Pardachirus marmoratus. Ear J Biochem 1996 Apr 1 237(1) 303-10. 

---