Establishing cultures of toxic dinoflagellate Dinophysis species and their prey

Donald M. Anderson, Biology

Grant Funded 2008

The dinoflagellate genus Dinophysis is of significant scientific and social importance. Many species in this genus produce toxins that accumulate in shellfish and cause diarrhetic shellfish poisoning (DSP) – a syndrome that heavily impacts public health and fisheries resources in many parts of the world. Interestingly, there is a large disparity in the areas of the world that are affected – while North America is virtually free of this poisoning syndrome, it is a major problem in Europe, South America, and Asia. Key aspects of Dinophysis physiology, toxicity, biogeography, and genetics have remained intractable due to the inability to grow and maintain these organisms in laboratory cultures. However, as a result of a recent breakthrough, this obstacle has been partly removed - cultures of a Woods Hole strain of Dinophysis have been growing at high rates in the PI’s laboratory for over one year at this writing. The key was the discovery that a three-stage culture system was needed – a cryptophyte alga is grown in unialgal culture and then is fed to the ciliate Myrionecta, which is in turn fed to the Dinophysis cells. Now that cultures are possible, a host of questions can be addressed, one of the most important being the reason behind the general lack of toxicity of North American strains of Dinophysis compared to other parts of the world.  Some obvious experiments are needed – to grow North American Dinophysis with ciliates and cryptophytes from toxic areas of the world, and vice versa – to grow toxic strains of Dinophysis (from Europe, for example) on ciliates and cryptophytes from Woods Hole. To explore this issue, the PI has submitted two proposals to NSF that have been declined for one major reason – our inability to demonstrate that we can culture toxic Dinophysis strains from outside the US. In effect, we have one part of the experimental system needed to advance this research, but lack the full complement of cultures. In the interim, we have spent considerable time and effort having plankton tow material shipped to us from Ireland, Sweden, and Chile, in hopes that the organisms we need to isolate will survive, but this has not worked. The NSF panel was correct – it is not a trivial undertaking. We thus propose a modest project that will provide funds for a member of the PI’s laboratory to travel to Europe to spend several weeks isolating cells and ciliates, after which the isolates can be carefully transported to the US. Once we have these cultures established, major funding from NSF is highly likely. There is thus considerable leveraging potential.
It has taken many years to reach the point where we can manipulate Dinophysis species in the laboratory. This one obstacle remains, and we hope that OLI support can make it possible to move this important line of research forward. Once we have the full culture system in place, with toxic and non-toxic culture systems, we can begin to answer longstanding questions in dinoflagellate physiology, ecology, toxicity, and evolution while also providing valuable information on a significant public health and economic problem.