The Effect of Aplysina Red Band Syndrome on Secondary Metabolite Production in the Sponge Aplysina cauliformis

Sponges on Caribbean reefs represent tremendous biomass and biodiversity, perform numerous critical ecological roles and produce an array of biologically active secondary metabolites. Thus, the health of sponges on coral reefs is important to the overall condition of these coral reef communities. In recent years, newly emerging diseases of sponges have been reported with increasing frequency. Aplysina Red Band Syndrome (ARBS) is a recently described disease affecting Caribbean rope sponges. Although the etiologic agent for this disease has not yet been characterized, it is believed to be a filamentous cyanobacterium, which forms a red band that progresses along the sponge, leaving necrotic tissue behind. Some sponges produce antimicrobial chemical defenses that may protect them from pathogens. To investigate whether differences in chemical defenses may explain why some individual sponges are susceptible to ARBS and others are not, we compared chemical profiles from healthy and diseased sponges. Several metabolites are produced in significantly different concentrations by healthy and diseased sponges. In addition, qualitative differences were observed. Since both healthy and diseased sponges were feeding deterrent, these compounds may represent antimicrobial chemical defenses that inhibit pathogenesis.