BACTERIA‐INDUCED MOTILITY REDUCTION IN LINGULODINIUM POLYEDRUM (DINOPHYCEAE)1 |
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| Authors: | Xavier Mayali Peter J S Franks Yuji Tanaka Farooq Azam |
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| Institution: | 1. Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093‐0202, USA;2. Author for correspondence: e‐mail .;3. Tokyo University of Marine Science and Technology, 4‐5‐7, Konan, Minato‐ku, Tokyo, 108‐8477, Japan |
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| Abstract: | Biotic factors that affect phytoplankton physiology and behavior are not well characterized but probably play a crucial role in regulating their population dynamics in nature. We document evidence that some marine bacteria can decrease the swimming speed of motile phytoplankton through the release of putative protease(s). Using the dinoflagellate Lingulodinium polyedrum (F. Stein) J. D. Dodge as a model system, we showed that the motility‐reducing components of bacterial‐algal cocultures were mostly heat labile, were of high molecular weight (>50 kDa), and could be partially neutralized by incubations with protease inhibitors. We further showed that additions of the purified protease pronase E decreased dinoflagellate swimming speed in a concentration‐dependent manner. We propose that motility can be used as a marker for dinoflagellate stress or general unhealthy status due to proteolytic bacteria, among other factors. |
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| Keywords: | algicidal bacteria dinoflagellate motility protease |
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