Exometabolites from the Mediterranean sponge Agelas oroides: where is oroidin?
Résumé
Sponges are filter-feeding sessile marine animals that are keystone species of various benthic ecosystems. They are known to produce a plethora of structurally diverse metabolites. Some of them are part of their toolbox for defense and communication strategies. When released, these (exo)metabolites may contribute to distant species interactions (Hay 2009; Santonja et al. 2018). In the course of our studies on the chemical
diversity of exometabolites from sponges, we wanted to know whether Agelas oroides (Schmidt, 1864), a rather dominant species of Mediterranean marine ecosystems, releases its characteristic bromo-pyrrole alkaloids. A series of captures and enrichment experiments were performed in aquaria and in situ (Mauduit et al. 2023). MS-based metabolomics revealed the paucity of bromo-pyrrole alkaloids as exometabolites. Oroidin was not detected in seawater despite being the most abundant compound in A. oroides extract (Fig. 1), and as opposed to published results with Agelas conifera (Richelle-Maurer et al. 2003).
Such findings prompted us to explore the fate of oroidin from the sponge biomass to the seawater. The
presentation will delve into these experimentations, and illustrate how examining organisms in their
ecosystems can lead to new discoveries even for extensively studied species.