Research Highlight: Scientists Crack the Code of Potent Sea Organism

When we think of the Bahamas we think of sun, vacation, and paradise. The last thing that comes to mind for most of us is the mud found at the bottom of the ocean.

Scientists at Scripps Institution of Oceanography at UC San Diego, on the other hand, have been putting lots of thought into Bahamian sediment after a 1991 discovery by William Fenical and Paul Jensen of a marine bacterium called Salinispora that’s shown potential in producing compounds that could treat diseases such as cancer. One such compound is in human clinical trials by Nereus Pharmaceuticals for treatment against plasma cell cancer and solid tumors.

In June, at the same time Fenical’s team was preparing to return to Bahamian waters in search of other new potent organisms, a Scripps team led by Bradley Moore and Daniel Udwary, in partnership with the Joint Genome Institute, announced they had sequenced the genome of the species Salinispora tropica.

Much of the hope for Salinispora comes from its potential to be a new source of antibiotics at a time in which many pathogenic bacteria strains are becoming drug-resistant. Currently terrestrially based Salinispora relatives called Streptomyces are responsible for producing more than half of the natural antibiotics used clinically.

After solving the genome, Moore and his colleagues were surprised at what they saw. Instead of finding that 6 to 8 percent of the genome is dedicated to producing antibiotic and anticancer agents, as with similar organisms, the Salinispora tropica genome revealed a surprising 10 percent.

With the genome map in hand, Moore and his colleagues are now able to investigate the potential of the organism’s ability to naturally produce compounds with disease-fighting potential. In the wild, the organism uses such molecules as a chemical defense and for nutrient scavenging.

Sequencing the Salinispora tropica genome will open the door to new engineering possibilities, including manipulating the genome to derive other potentially powerful compounds and finding ways to increase compound manufacturing capabilities.

“If we know the genetic roadmap of their potential, we can read the sequence and the DNA to predict what chemicals are being made,” said Moore. “This is a way to mine the genomes for new chemical structures and new biology, with potential in a human health context.”

The achievement will be published in an upcoming edition of the Proceedings of the National Academy of Sciences.

--Mario C. Aguilera