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Alkaloids and ascidian chemical defense: Evidence for the ecological role of natural products from Eudistoma olivaceum

Journal Article


Abstract


  • The surface of the colonial ascidian Eudistoma olivaceum (Van Name) is almost completely free of fouling organisms. I provide evidence that this epibiont-free surface is maintained by the alkaloids, Eudistomins G and H. These alkaloids were extracted from colonies collected in the shallow subtidal of Indian River Lagoon, Florida. USA, in November 1987. Concentrations of less than one-fifth of those found in the living ascidian inhibited the settlement of the larvae of five invertebrate species relative to appropriate controls in laboratory and field trials. Standard pharmacological assays have revealed that Eudistomins G and H were not the most biologically active of the eudistomins, indicating that these standard assays are not necessarily good predictors of antifouling activity. In an examination of possible alternate roles for these eudistomins, they proved ineffective as a fish antifeedant. Pinfish Lagadon rhomboides consumed agar pellets to which Eudistomins G and H had been added at concentrations 10- to 100-fold higher than those effective against settling larvae. These findings indicate that biologically active marine natural products may serve specific ecological roles. © 1991 Springer-Verlag.

Publication Date


  • 1991

Citation


  • Davis, A. R. (1991). Alkaloids and ascidian chemical defense: Evidence for the ecological role of natural products from Eudistoma olivaceum. Marine Biology, 111(3), 375-379. doi:10.1007/BF01319409

Scopus Eid


  • 2-s2.0-0001052603

Start Page


  • 375

End Page


  • 379

Volume


  • 111

Issue


  • 3

Abstract


  • The surface of the colonial ascidian Eudistoma olivaceum (Van Name) is almost completely free of fouling organisms. I provide evidence that this epibiont-free surface is maintained by the alkaloids, Eudistomins G and H. These alkaloids were extracted from colonies collected in the shallow subtidal of Indian River Lagoon, Florida. USA, in November 1987. Concentrations of less than one-fifth of those found in the living ascidian inhibited the settlement of the larvae of five invertebrate species relative to appropriate controls in laboratory and field trials. Standard pharmacological assays have revealed that Eudistomins G and H were not the most biologically active of the eudistomins, indicating that these standard assays are not necessarily good predictors of antifouling activity. In an examination of possible alternate roles for these eudistomins, they proved ineffective as a fish antifeedant. Pinfish Lagadon rhomboides consumed agar pellets to which Eudistomins G and H had been added at concentrations 10- to 100-fold higher than those effective against settling larvae. These findings indicate that biologically active marine natural products may serve specific ecological roles. © 1991 Springer-Verlag.

Publication Date


  • 1991

Citation


  • Davis, A. R. (1991). Alkaloids and ascidian chemical defense: Evidence for the ecological role of natural products from Eudistoma olivaceum. Marine Biology, 111(3), 375-379. doi:10.1007/BF01319409

Scopus Eid


  • 2-s2.0-0001052603

Start Page


  • 375

End Page


  • 379

Volume


  • 111

Issue


  • 3