Presenter: Marina Gerton
Authors: Marina Gerton, Bailey Miller, Eric Schmidt
Faculty Advisor: Eric Schmidt
Institution: University of Utah
Shipworms are wood-digesting marine bivalves that rely upon symbiotic bacteria for cellulose digestion. These symbiotic bacteria, which grow intracellularly in the gill tissue, produce cellulases that are then transported to the shipworm’s cecum. It has also been hypothesized that the bacteria produce antibiotics, exported to the cecum with the cellulases, to prevent microbial glucose scavenging upon cellulose digestion, thus making the bacteria medicinally interesting. While various species of bacteria can form symbioses with shipworms, the most well-characterized is Teredinibacter turnerae, in part due to the success of in-lab culturing. Nonetheless, the lab growth conditions are significantly different from the in-situ environment, as the physical conditions of intracellular growth are incredibly difficult to replicate with flask or fermenter culturing and the chemical conditions would require complex and potentially expensive media. Since physical and chemical growth conditions will both affect microbial metabolism, these conditions will also affect growth patterns and secondary metabolite production. To investigate these effects, various growth conditions (such as temperature, presence of cytosolic compounds, and carbon source, among others) were manipulated to study how they might impact secondary metabolite production of the bacteria. Compounds produced by the bacteria are isolated, purified via HPLC, and analyzed using NMR and mass spectrometry. By more closely replicating the growth conditions found in the bacteria’s natural environment, and generally changing conditions known to impact metabolic activity, it may be possible to promote the production of antibiotics not seen under standard culture conditions. Given that some compounds previously isolated from T. turnerae have demonstrated activity against gram-negative bacteria, and even some antibiotic-resistant strains, any novel isolated bioactive compounds from these experiments have the potential to be incredibly useful medicinally, and the experiments as a whole can provide an indication of what growth conditions might effectively promote silent gene clusters of particular interest.