Developing a new resource for drug discovery: marine actinomycete bacteria

Natural products are both a fundamental source of new chemical diversity and an integral component of today's pharmaceutical compendium. Yet interest in natural-product drug discovery has waned, in part owing to diminishing returns from traditional resources such as soil bacteria. The oceans cover 70% of the Earth's surface and harbor most of the planet's biodiversity. Although marine plants and invertebrates have received considerable attention as a resource for natural-product discovery, the microbiological component of this diversity remains relatively unexplored. Recent studies have revealed that select groups of marine actinomycetes are a robust source of new natural products. Members of the genus Salinispora have proven to be a particularly rich source of new chemical structures, including the potent proteasome inhibitor salinosporamide A, and other distinct groups are yielding new classes of terpenoids, amino acid-derived metabolites and polyene macrolides. The continued development of improved cultivation methods and technologies for accessing deep-sea environments promises to provide access to this significant new source of chemical diversity.