Characterization of an Algicidal Agent Produced by Shewanella sp.

             Dinoflagellates are a group of algae that include many toxic species, such as those that cause “red tides” in the Gulf of Mexico and also those that are responsible for paralytic and neurotoxic shellfish poisonings. Dinoflagellate blooms in the mid-Atlantic region also pose a serious threat to human health and marine life, yet there are no measures in place for rapid response and mitigation of harmful dinoflagellate blooms in this region. In previous research at UD, Hare et al. (2004) described a bacterium that specifically inhibited the growth of dinoflagellates. Ongoing research on the algicidal bacterium in Coyne’s laboratory demonstrated that direct contact between the bacterium and the dinoflagellate is not required for algicidal activity, and the algicidal agent (IRI-160AA) has no impact on the growth of other classes of phytoplankton. Our data suggest that IRI-160AA may be an effective tool for controlling dinoflagellate growth, precisely targeting these species without impacting other algal groups.

            While this algicidal compound may someday provide a means to control or even prevent harmful dinoflagellate blooms, more work is needed before it can be safely used in the environment.  In this project, we are continuing to characterize the activity of IRI-160AA on dinoflagellate physiology and toxicity, and also evaluating the effect of this compound on microalgae in mixed culture experiments, and on microbial community structure and function in natural community experiments. 

        Investigators: Kathryn J. Coyne ( & Mark E. Warner ( Funded by a grant from the National Oceanic and Atmospheric Administration (NOAA).

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