NEW METABOLITES FROM MARINE SPONGES - ARE SYMBIONTS IMPORTANT

It has frequently been suggested that symbionts may produce marine natural products obtained from sponges. A critical examination of this hypothesis reveals little supporting data although there may be circumstantial evidence favouring the involvement of symbionts. Examination of the relationship between the sponge Dysidea herbacea and the blue-green alga Oscillatoria spongeliae has revealed that the polychlorinated amino-acid derivatives are localized in and presumably produced by O. spongeliae. Preliminary research on lithistid sponges suggests that the cyclic peptides found in these sponges may be produced by filamentous micro-organisms that are found in great abundance within the sponge tissues.