Some aspects of chemical ecology of the sponges of the Caribbean, Axinyssa ambrosia and Aplysina insularis

Abstract:

[en] Axinyssamine hydrochloride (compound 1) was recently found in the marine sponge Axinyssa ambrosia at concentrations in the order of 10 mg/ml. Lethality assays using compound 1 against the coral Madracis mirabilis allowed determining that the mentioned compound is lethal to coral polyps at the natural concentration present in the sponge. Additionally, by performing exudation experiments in aquaria and chemical detection by HRGC-MS (scan and sim modes) it was found that the compounds ll-formamide-7β-H-eudesm-5-ene (2) and 4 α-formamidogorgon-ll-ene (3) are continually exuded by Axinyssa ambrosia creating a protective chemical barrier around the sponge. Exudation rates increase 3.80 and 2.47 fold respectively for each compound, under stress conditions or aggression. These results suggest that the sponge Axinyssa ambrosia may use the above-mentioned three metabolites as chemical defenses. Other experiments were carried out with the sponge Aplysina insularis in situ, under ecologically relevant conditions, with the purpose of determining if the chemical composition (Brominated metabolites) changes over variable time periods after inflicting wounds on the sponge surface. Metabolites were detected and identified by LC-MS. No evidence of chemical transformation of high molecular weight compounds into the compounds Aeroplysinin-l (4) and/or the dibromo cyclohexadienone (5) was obtained as a consequence of tissue damage, both in short (2, 5 minutes) and long duration experiments (120 minutes). These results suggest that the conversion of high molecular weight compounds into small, active forms does not …

Año de publicación:

2002

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