Drug Discovery on ocean floor

The deep ocean may be the next frontier in drug discovery. Analyses of sediment samples from beneath the ocean floor found evidence of life, primarily fungi, which could harbor as-yet undiscovered antibiotics or other potential drugs.

There’s life down there, deep beneath the ocean floor. Recently reported from scientists at Woods Hole Oceanographic Institute where they collected and analyzed sediment samples at depths up to 50 meters below the sea floor[1]. This news brings a certain “wow factor” that there is so much life at these depths, and the hope that the finding will fuel new drug discovery.

We have long looked to Mother Nature for help with drug discovery[2]. Aspirin came from the bark of a willow tree. Penicillin, the great antibiotic of our time, derives from the fungus Penicillium.  Turning to nature for drug discovery has been more productive than sophisticated drug-screening technologies developed in the lab[3], and has yielded a surprising diversity of drugs to add to our chemical arsenal. Taxol®, one of the strongest cancer drugs on the market, is derived from the bark of the Pacific Yew tree. A Caribbean sea sponge turned out to be the source of Cytosar-U®, a widely used drug against leukemia and lymphoma. Because of these past successes, the pharmaceutical industry is keen to find new sources of biological specimens to mine for drug discovery.

To find life beneath the ocean floor, scientists analyzed sediment samples for ribosomal RNA (rRNA)[1]. Unlike DNA, which can stick around in dead cells or even extracellularly, rRNA is less stable and more likely to be associated with metabolically active organisms. They found more diversity in samples closer to the sea floor, with metazoans, protists, plant matter, and green algae.  In the deepest samples, fungi predominated.

As best, they can tell these fungi are unique creatures. Fungal spores are often carried along in the wind from Africa, Asia, and the Middle East, only to be deposited in the ocean. But few of the fungal genra carried in the winds were represented in the collected samples. We don’t know where these fungi came from, but the environmental pressures they experience deep beneath the ocean floor and their physical isolation likely means there are novel species down there. Perfect for new drug discovery!

References

  1. Orsi W, Biddle JF, Edgcomb V (2013) Deep Sequencing of Subseafloor Eukaryotic rRNA Reveals Active Fungi across Marine Subsurface Provinces. PLoS ONE 8(2): e56335. doi:10.1371/journal.pone.0056335
  2. Medicines by Design: Drugs from Nature, Then and Now. National Institute for General Medical Sciences.
  3. 70% of New Drugs Come from Mother Nature, Mongabay.  March 20, 2007.