Elysia rufescens

The receptors of ecological interactions are still not well understood. In fact, many ecological studies have failed to demonstrate well-defined roles for natural products (Pawlik 1993). Most experimental evidence for natural product receptors derives from biomedical applications. Kahalalide F, for example, is a potent cytotoxic depsipeptide (see Sect. 1.3.2.3) initially found in the sacoglossan mollusc Elysia rufescens and later in the green alga it feeds upon (Hamann and Scheuer... 

Hamann, M. T. and Scheuer, P. J., Kahalide F a bioactive depsipeptide from the sacoglossan mollusk Elysia rufescens and the green alga Bryopsis sp., J. Am. Chem. Soc., 115, 5825, 1993. 

The Hawaiian sacoglossan Elysia rufescens sequesters the depsipeptide metabolite kahalalide F 184 from its algal diet Bryopsis sp. Both algal and mollusk extracts were deterrent when tested against natural populations of reef fish, as was the peptide metabolite.208 Kahalalide F shows potent cytotoxicity against a range of tumor cell lines.209... 

Kalahalide D (41) has been isolated from the marine mollusk Elysia rufescens and from the alga Bryopsis sp. and identified by analysis of spectroscopic data, chemical degradations, and chiral HPLC, GC, and TEC [65]. 

Hamann, M.T. Otto, C.S. Scheuer, P.J. Dunbar, D.C. Kahalalides Bioactive Peptides from a Marine MoIIusk Elysia rufescens and Its Algal Diet Bryopsis sp. J. Org. Chem.1996, 61, 6594-6600. 

Depsipeptide antibiotic. Isol. from the mollusc Elysia rufescens and the alga Bryopsis sp. Cytotoxic. White powder, [a] —8 (c, 4.32 in MeOH). 

Goetz, G., Nakao, Y, and Scheuer, P.J. (1997) Two acydic kahalalides from the sacoglossan mollusk Elysia rufescens. J. Nat. Prod., 60, 562-567. 

---