Inhibition of byssal thread formation of Limnoperna fortunei by natural products isolated from the brown alga Dictyota dichotoma

GARCÍA, M.; SILESS, G.; PEREZ, M.; STUPAK, M.; PALERMO, J.

Newcastle, Inglaterra

Congreso; 15th International Congress on Marine Corrosion and Fouling (15th ICMCF),; 2010

Newcastle University

The Asiatic freshwater mollusk, Limnoperna fortunei (golden mussel), is an introduced species of bivalve.  Since their discovery in 1991, they have spread rapidly throughout Río de la Plata basin, colonizing Paraná, Paraguay and Uruguay rivers, and Pantanal (Central West Brazil). The golden mussels attach using their glue-like byssal threads to almost any hard surface and can form thick mats of several hundred thousand individuals per square meter. These mussels spend their adult lives attached to hard substratum such as rock and cobble, as well as concrete, iron, polyvinyl chloride, plastic, and fiberglass. Piping systems at public and private facilities that use raw water are particularly susceptible to golden mussel infestations. For this reason, there is great interest in devising non-toxic methods to control mussel settlement.  It is well known that many marine algae and invertebrates remain remarkably free from settlement by fouling organisms. It has been suggested that they have biologically active compounds that prevent other marine organisms from settling and attaching to their bodies. Some investigations showed that secondary metabolites of seaweed Dictyota dichotoma are responsible of the antifouling activity on marine organisms. We hypothesized that three pure compounds, pachydictyol, dictyotadiol and dictyoxide, isolated from the alga Dictyota dichotoma could be employed against the establishment of the mussel Limnoperna fortunei. For this purpose, a laboratory screening method for the evaluation of byssal thread formation was used [1]. Briefly, the number of byssal thread attached inside a circle embedded of the test compound vs a control at the end of 24 hours was recorded. Experiments indicated that pachydictyol and dityoxide have strong inhibition activity on byssal thread production in concentrations as low as 6.7µg/cm2.  In contrast, dictyotadiol is not a good candidate for new antifouling treatment because golden mussels were not affected on byssal threads production. These findings represent the first report of the use of secondary metabolites from a marine alga to avoid Limnoperna fortunei settlement. Results suggest the potential utility of these compounds for the development of antifouling technology.