抄録
Coral bleaching is a recognized phenomenon of the biological impacts of global warming on marine ecosystems. Currently, the exact mechanism involved in the heat induced-coral bleaching phenomenon is still unclear. A recent study has suggested an implication of nitric oxide (NO) in the mechanism leading to the expulsion of symbiotic algae from the coral host. Here we show that the dinoflagellate Symbiodinium microadriaticum produces NO when supplemented with either nitrite or L-arginine as a substrate. This production of NO was confirmed by electrochemical and fluorimetric techniques. When S. microadriaticum were exposed to an acute heat stress (from 27 to 41 °C), an increase in NO production was observed along with a decrease in photosynthetic efficiency, thereby suggesting that excessive NO production upon heat stress could be detrimental to the cells. The implications of these findings are discussed in the light of the coral bleaching phenomenon.
