Photoregulation in a Kleptochloroplastidic Dinoflagellate, Dinophysis acuta.
Some phagotrophic organisms can retain chloroplasts of their photosynthetic prey as so-called kleptochloroplasts and maintain their function for shorter or longer periods of time. Here we show for the first time that the dinoflagellate Dinophysis acuta takes control over "third-hand" chloroplasts obtained from its ciliate prey Mesodinium spp. that originally ingested the cryptophyte chloroplasts. With its kleptochloroplasts, D. acuta can synthesize photosynthetic as well as photoprotective pigments under long-term starvation in the light. Variable chlorophyll fluorescence measurements showed that the kleptochloroplasts were fully functional during 1 month of prey starvation, while the chlorophyll a-specific inorganic carbon uptake decreased within days of prey starvation under an irradiance of 100 μmol photons m(-2) s(-1). While D. acuta cells can regulate their pigmentation and function of kleptochloroplasts they apparently lose the ability to maintain high inorganic carbon fixation rates.
Marine Biological Section, Department of Biology, University of Copenhagen Helsingør, Denmark.
Per J
PJ
Hansen
Marine Systems Institute, Tallinn University of Technology Tallinn, Estonia.
Karin
K
Ojamäe
Marine Biological Section, Department of Biology, University of CopenhagenHelsingør, Denmark; Centre for Ocean Life, DTU Aqua National Institute for Aquatic Resources, Technical University of DenmarkCharlottenlund, Denmark.
Terje
T
Berge
Marine Biological Section, Department of Biology, University of Copenhagen Helsingør, Denmark.
Erik C L
EC
Trampe
Centre for Ocean Life, DTU Aqua National Institute for Aquatic Resources, Technical University of Denmark Charlottenlund, Denmark.
Lasse T
LT
Nielsen
Marine Systems Institute, Tallinn University of Technology Tallinn, Estonia.
Inga
I
Lips
Marine Biological Section, Department of Biology, University of CopenhagenHelsingør, Denmark; Plant Functional Biology and Climate Change Cluster, University of Technology SydneySydney, NSW, Australia.
Michael
M
Kühl
Dinophysis; acquired phototrophy; kleptochloroplasts; photoregulation; photosynthesis