Planta Med 2016; 82(S 01): S1-S381
DOI: 10.1055/s-0036-1596656
Abstracts
Georg Thieme Verlag KG Stuttgart · New York

Defensive chemistry of the Irish nudibranch Archidoris psuedoargus (Gastropoda opisthobranchia)

RM Young
1   School of Chemistry, National University of Ireland Galway, Galway, Republic of Ireland
2   Department of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, 33620, FL, USA
,
BJ Baker
1   School of Chemistry, National University of Ireland Galway, Galway, Republic of Ireland
2   Department of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, 33620, FL, USA
› Author Affiliations
Further Information

Publication History

Publication Date:
14 December 2016 (online)

 

Historically, marine natural products from the Republic of Ireland have been greatly underrepresented in the literature despite having a coastline of over 4500 miles. Archidoris pseudoargus is a soft-bodied, slow moving Dorid nudibranch which inhabits the coastal waters of Ireland and the United Kingdom. Nudibranchs are a good source of new chemical diversity, employing these secondary metabolites to deter predation. In this study we have identified new chemistry as well as used a metabolomics approach to identify the origin of said chemistry as well as trends in morphologically different individuals. From our initial findings the individual organisms group together into several clusters based on their metabolomic profiles (Figure 1 right). The major metabolites isolated thus far from these organisms are diterpene glycerides (e.g., 1 and 2) which have been shown to be icthyotoxins [1] suggesting these metabolites are the nudibranchs method of defense against predation.

In early Spring, mature adults come together to reproduce and shortly thereafter to oviposit on the subtidal rocky shoreline. These egg sacs can be brightly coloured and are readily exposed to predation, yet none of the many surrounding predators appear to feed on these nutrient rich egg masses. Using UPLCMS-MS on standards isolated from the bulk A. psuedoargus extraction, we have shown that the same diterpenes present in the mantle tissue of the adults is transferred into the egg masses from the parent organism which in turn protects them against predators.

Zoom Image
Fig. 1: Left: Representative A. psuedoargus chemistry. Right: MDS plot showning differences in metabolomic profiles of the diterpenoids (30 < C > 20) of individials collected from the same location. Solid (> 50%) and broken lines (> 60%) indicate varing degrees of similarity between data points.

Acknowledgements: Beaufort Marine Research Award: This Beaufort Marine Research Award is carried out under the Sea Change Strategy and the Strategy for Science Technology and Innovation (2006 – 2013), with the support of the Marine Institute, funded under the Marine Research Sub-Programme of the National Development Plan 2007 – 2013.

Keywords: nudibranch, diterpenes, metabolomics, defensive chemistry.

References:

[1] Cimino G, Gavagnin M, Sodano G, Puliti R, Mattia CA, Mazzarella L. Verrucosin-a and -b, ichthyotoxic diterpenoic acid glycerides with a new carbon skeleton from the dorid nudibranch Doris verrucosa. Tetrahedron 1988; 44, 2301 – 2310