Localisation of bioactive metabolites in marine sponges

Marine natural product chemists have often proposed that bioactive sponge metabolites are produced by symbiotic micro-organisms. This paper discusses the rationale for these proposals, reviews the strengths and weaknesses of methods that are available to test such hypotheses and reports some experimental studies. The conclusion reached from the research to date is that it is too early to make generalisations concerning either the role of symbionts in the biosynthesis of sponge metabolites or even the best techniques for studying the cellular localisation of bioactive metabolites.