Wednesday 25 September 2013 at 11:00am

Title: “The extraordinary biology of shipworms and their endosymbionts: a reservoir of cellulases and antimicrobials”

Speaker: Roberta O'Connor, Ph.D.
Research Scientist, Ocean Genome Legacy

Abstract:
Shipworms are marine bivalves that burrow into and eat wood. Like most xylophagous animals, this lifestyle is enabled by a community of cellulolytic symbiotic bacteria. In the shipworm, however, the symbiont community is found cloistered within the cells of gill, sequestered away from the digestive tract. In contrast, the caecum, the primary site of wood digestion, is nearly free of bacteria. Using a combination of metagenomics, genomics, proteomics, bioinformatics and old fashioned protein chemistry, we have shown that the gill endosymbionts, despite their location, provide the enzymes for the wood digestion in the gut. Thus the shipworm caecum is a natural “bioreactor” that may provide valuable information to improve commercial biofuel production. In addition to celluolytic enzymes, the genomes of shipworm symbionts also display a significant investment in secondary metabolite synthesis. This capacity, combined with the ability of shipworm symbionts to produce compounds that move through multiple cellular compartments and influence processes distant from their living quarters, suggested a reservoir of unusual anti-microbial compounds worthy of investigation. We tested this hypothesis by screening symbionts for activity against the apicomplexan parasites Toxoplasma and Cryptosporidium, and discovered a symbiont that secretes a compound inhibitory to intracellular growth of both these pathogens. These results suggest that mining shipworms symbionts for bioactive compounds could open up a new area of anti-parasitic drug discovery and potentially identify new molecular targets for drug development.

Host: Russell Hill, Ph.D.